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  • Articles  (861)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 32 (1993), S. 71-73 
    ISSN: 1436-6215
    Keywords: Rat ; glutamate-induced obesity ; postprandial thermogenesis ; Ratte ; Glutamat-induzierte Adipositas ; postprandiale Thermogenese
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Bei 4 Monate alten Ratten mit Glutamat-induzierter Adipositas wurde die postprandiale Thermogenese über 8 h nach Fütterung von 300, 450 und 600 kJ/kg0,75 einer Pellet-Diät mittels indirekter Kalorimetrie in computergesteuerten Stoffwechselkäfigen mit offenem Kreislauf bestimmt. Bei den adipösen Tieren war die postprandiale Thermogenese nach Aufnahme von 600 kJ/kg0,75 (oberhalb des Energieerhaltungsbedarfs) signifikant auf 40% der Thermogenese der Kontrolltiere reduziert (12,0 gegenüber 31,5 kJ/kg0,75×8 h). Es wird geschlußfolgert, daß die Ratte mit Glutamat-induzierter Adipositas als ein Tiermodell mit beeinträchtigter fakultativer Thermogenese anzusehen ist, die hauptsächlich durch eine Verminderung der sympathischen adrenergen Aktivität verursacht ist.
    Notes: Summary Postprandial thermogenesis was estimated in 4-month-old male rats with glutamate induced obesity after being fed with 300, 450 and 600 kJ/kg0.75 of a pellet diet, respectively by indirect calorimetry in computer-controlled open circuit metabolic cages over 8 h. After an intake of 600 kJ/kg0.75 (above the maintenance energy requirement) postprandial thermogenesis was significantly reduced in the obese animals to about 40% of control rats (12.0 versus 31.5 kJ/kg0.75×8 h). It is concluded that the glutamate obese rat can be accepted as an animal model with impaired facultative thermogenesis, mainly caused by a reduction of sympathetic adrenergic activity.
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  • 2
    ISSN: 1435-604X
    Keywords: Brain tumour ; Rat ; Detection ; Fluorescence ; Laser ; Haematoporphyrin derivative
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Laser-induced fluorescence has been used for the identification of brain tumours in rats, which have been previously given tumour-seeking haematoporphyrin derivative. A pulsed nitrogen laser (λ=337 nm) was used in conjunction with an optical multichannel analyzer. For both inoculated RG-2 and TCVC rat-brain-tumour models, the blue autofluorescence was strongly reduced in the tumour compared with normal brain tissue, and at the same time the characteristic red-drug signal increased. The contrast between tumour and normal tissue was strongly enhanced by forming the ratio between the two signals. Implications for possible improvement of tumour delineation in brain tumour surgery are discussed.
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  • 3
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    Cellular and molecular life sciences 40 (1984), S. 1004-1006 
    ISSN: 1420-9071
    Keywords: Rat ; adrenocortical responsiveness ; ACTH ; plasma ; corticosterone ; plasma ; corticotropin releasing factor (CRF)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the course of studying the plasma adrenocorticotropic hormone (ACTH) and corticosterone responses to synthetic corticotropin releasing factor (CRF), we noted some disparity in the responses. A higher dose (20 μg compared with 5 μg per rat i.a.) produced an equal plasma ACTH but greater plasma corticosterone response in adult male rats. Thus, we examined the possibility that CRF increases adrenocortical responsiveness to ACTH. CRF significantly (p〈0.0005) increased the plasma corticosterone response to ACTH in rats pretreated with dexamethasone. Thus, synthetic CRF increases corticosterone secretion in rats not only by stimulating ACTH secretion, but also by increasing the adrenocortical responsiveness to ACTH.
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  • 4
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    Cellular and molecular life sciences 41 (1985), S. 265-266 
    ISSN: 1420-9071
    Keywords: Rat ; hydrochlorothiazide ; pain threshold ; antinociceptive activity ; analgesic activity ; morphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hydrochlorothiazide, acutely injected in rats, has a weak analgesic activity per se and potentiates and prolongs the antinociceptive effect of morphine.
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  • 5
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    Cellular and molecular life sciences 46 (1990), S. 457-458 
    ISSN: 1420-9071
    Keywords: Rat ; carnitine ; lipolysis ; exercise ; glycogen ; triglycerides ; muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise.
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  • 6
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    Cellular and molecular life sciences 40 (1984), S. 974-975 
    ISSN: 1420-9071
    Keywords: Rat ; prostaglandins ; gastric lesion ; intragastric distension model ; stress model ; indomethacin ; somatostatin preventive effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The inhibition of endogenous prostaglandin synthesis by indomethacin treatment blocks the somatostatin preventive effect on the gastric lesions induced in a stress model and has no preventive effect on an intragastric distension model.
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  • 7
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    Calcified tissue international 10 (1972), S. 82-90 
    ISSN: 1432-0827
    Keywords: Calcium ; Phosphate ; Precipitation ; Kinetics ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La cinétique de la formation et de la transformation des précipités de phosphate de calcium, obtenus en mélangeant de volumes égaux de solutions à 6×10−3 M de calcium total et/ou phosphate total est étudiée à 25°C. Les solutions de phosphate sont préajustées à un pH de 7.4. Les changements de pH et de turbidité des solutions sont suivis simultanément en fonction du temps. Les précipités sont isolés à des intervalles de temps variables et caractérisés par diverses méthodes physico-chimiques. Initialement un précipité avec un rapport molaire Ca/P de 1.5, amorphe aux rayons X et en diffraction électronique, est formé. Le spectre IR indique la présence de PO 4 3− et de HPO 4 2− . Après une période métastable, on observe la précipitation d'un matériel cristallin dans ou sur la phase amorphe. Vingt quatre heures après préparation de l'échantillon les précipités présentent surtout les caractères du phosphate octocalcique.
    Abstract: Zusammenfassung Die Kinetik der Bildung und Transformation von Calciumphosphat-Niederschlägen wurde bei 25°C untersucht. Es wurden dazu gleiche Volumen von Lösungen gemischt, bei einer Konzentration von 6×10−3M totales Calcium und/oder totales Phosphat. Die Phosphatlösungen wurden zuerst auf pH 7,4 eingestellt. Veränderungen des pH und Trübung der Lösungen wurden gleichzeitig als eine Funktion der Zeit aufgezeichnet. Niederschläge wurden in verschiedenen Zeitintervallen isoliert und mit verschiedenen physiko-chemischen Methoden charakterisiert. Am Anfang wurde ein Niederschlag mit einem molaren Ca/P-Verhältnis von 1,5, im Röntgenbild und in der Elektronendiffraktion amorph, gebildet. Infrarotspektren deuteten die Anwesenheit von PO 4 3− - und HPO 4 2− -Ionen an. Nach einer metastabilen Periode erfolgte ein Niederschlag aus kristallinem Material innerhalb oder auf der amorphen Substanz. 24 Std nach der Herstellung der Proben zeigten die Niederschläge in der Hauptsache die Charakteristiken von Octocalciumphosphat.
    Notes: Abstract The kinetics of the formation and transformation of calcium phosphate precipitates obtained by mixing equal volumes of solutions, 6×10−3 M in total calcium and/or total phosphate was investigated at 25°. The phosphate solutions were preadjusted to pH 7.4. Changes of the pH and turbidity of the solutions were followed simultaneously as a function of time. Precipitates were isolated at various time intervals and characterized by different physicochemical methods. Initially a precipitate with a molar Ca/P ratio of 1.5, amorphous to X-ray and electron diffraction was formed. IR spectra indicated the presence of PO 4 3− and HPO 4 2− ions. After a period of metastability, precipitation of a crystalline material within or upon the amorphous matter occurred. Twenty four hours after sample preparation the precipitates showed mainly the characteristics of octacalcium phosphate.
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  • 8
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    Calcified tissue international 10 (1972), S. 238-251 
    ISSN: 1432-0827
    Keywords: Growth ; Bone ; Rat ; Tetracycline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La vitesse de croissance normale en longueur de la métaphyse proximale du tibia est déterminée chez le rat Sprague-Dawley entre les âges de 20 et 100 jours, en utilisant la méthode à la tétracycline. Le taux de croissance ne varie que légèrement dans les groupes d'âges différents. Il est plus élevé chez les animaux jeunes et décroit considérablement en fonction de l'augmentation de l'âge. Les rats mâles présentent une croissance plus élevée que les femelles. Cette étude a pour but de mettre au point une méthode permettant de déterminer les facteurs expérimentaux, liés à la croissance en longueur du rat.
    Abstract: Zusammenfassung Die normale Längenwachstums-Geschwindigkeit der proximalen Wachstumsplatte der Tibia wurde bei Sprague-Dawley-Ratten in einem Alter zwischen 20 und 100 Tagen mittels der Tetracyclinmethode gemessen. Die Wachstumsgeschwindigkeit variierte nur wenig innerhalb der einzelnen Altersgruppen. Die Geschwindigkeit war bei jungen Tieren am höchsten und nahm mit zunehmendem Alter beträchtlich ab. Männliche Ratten wuchsen schneller als weibliche. Diese Arbeit dient als Grundlage, um die experimentelle Beeinflussung des Längenwachstums der Ratte abschätzen zu können.
    Notes: Abstract The rate of normal growth in length from the proximal growth plate of the tibia in the Sprague-Dawley rat was measured between 20 and 100 days of age using the tetracycline method. The growth rate varied only slightly within different age groups. The rate was highest in young animals and decreased considerably with increasing age. Male rats grew faster than female. This study is intended to provide a base for an evaluation of experimental influence on the growth in length of the rat.
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  • 9
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    Calcified tissue international 16 (1974), S. 145-152 
    ISSN: 1432-0827
    Keywords: EHDP ; Bone ; Chemistry ; Serum ; Rabbits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The effects of disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) on bone and serum chemistry were investigated in adult rabbits. EHDP was administered by subcutaneous injection at doses of 0.25, 2.5 and 10 mg/kg body weight/day for of 28 days. Blood samples were obtained weekly from each rabbit and serum levels of total calcium, ionized calcium, inorganic phosphate and alkaline phosphatase were determined. At the end of the treatment period all rabbits were sacrificed and the tibiae removed for chemical analysis and histological evaluation. The effect of EHDP administration on serum chemistry was both dose- and time-related. The highest of the three doses, 10 mg/kg/day, resulted in a time-related decrease in total serum calcium. This dose also caused a rapid but transient reduction in serum ionized calcium. The effect of EHDP on serum inorganic phosphate was biphasic. Administration of 2.5 mg/kg/day resulted in a time-related elevation in this parameter, whereas the 10 mg/kg/day dose resulted in a time-related hypophosphatemic response. There were no significant drug-related changes in tibial fat-free dry weight, ash weight, total calcium or total phosphorus values. However, administration of 2.5 and 10 mg/kg/day EHDP resulted in increased osteoid tissue as measured histologically. These results are compared with data from other EHDP studies, and discussed in relation to the maturity and growth-state of the experimental animals.
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  • 10
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    Calcified tissue international 3 (1969), S. 96-99 
    ISSN: 1432-0827
    Keywords: Calcium metabolism ; Strontium metabolism ; Fracture ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La relation entre la résorption du85Sr et du47Ca était mesuré au tibia et fémur des rats 24 heures après l'injection. La différence entre les manches et les bouts était, remarquable, mais pas entre les os séparates; en les tibiae, qui etait fracturé depuis 7 semaines et guéries, la relation etait identique à celui des tibiae manches normals. On a présumé que la découverte était due à des différences qualitatives plustot que quantitatives entre les procédé de minéralisation dans l'os cortical et trabeculair.
    Abstract: Zusammenfassung Das Verhältnis zwischen der Abnahme von85Sr und47Ca wurde von der Tibia und Femur 24 Std nach der Injektion bei Ratten gemessen. Man fand einen signifikanten Unterschied zwischen den Schaften und den Enden, aber nicht zwischen den verschiedenen Knochen. In 7 Wochen alten, verheilten Tibiafrakturen war das Verhältnis genau so wie in einem normalen Tibiaschaft. Das Resultat berechtigte zu der Annahme, daß der Unterschied in dem Mineralisierungsprozeß zwischen corticalen und spongiösen Knochen wahrscheinlich qualitativ und nicht quantitativ ist.
    Notes: Abstract The ratio between the uptake of85Sr and47Ca was measured in the tibiae and femora of rats 24 h after injection of the tracers. There was a significant difference between shafts and ends but not between the different bones; in healed tibial fractures, 7 weeks old, the ratio was identical to that of normal tibial shafts. The findings were interpreted to be related to qualitative rather than quantitative differences in mineralization between cortical and trabecular bone.
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  • 11
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    Calcified tissue international 23 (1977), S. 161-170 
    ISSN: 1432-0827
    Keywords: Bone ; Growth ; Rat ; Remodeling ; Tetracyclines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Cortical bone remodeling along the femur diaphysis was determined in normal female rats (Sprague-Dawley) with the tetracycline technique. Three segments on the cortical bone circumference (the anterolateral, the medial, and the posterior) were found to be most suitable for the study of the remodeling process. Oxytetracycline was administered at age 60 and 75 days, and groups of animals were killed at age 75, 85, 95, and 105 days. The accumulated endosteal growth during age 60 to 75 days in the anterolateral segment was found to increase uniformly in the distal direction along the femur diaphysis. A method is described where this accumulated endosteal growth is used. This method eliminates the use of calipers to determine the section level and makes it possible to study comparable sections even after varying periods of time. The proximal part of the diaphysis showed periosteal apposition in all three segments. The periosteal apposition turned into resorption in the distal part of the diaphysis in the anterolateral and medial segments, whereas the periosteal appsition increased in the posterior segment. The endosteal growth increased in the distal direction in the anterolateral and medial segments. Irregular OTC bands made measurements of endosteal remodeling in the posterior segment impossible. The cortical width decreased in the distal direction along the femoral shaft. Comparison between the different age groups is described and also the relation between the accumulated endosteal growth and the diameter of the medullary cavity.
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  • 12
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    Calcified tissue international 23 (1977), S. 13-17 
    ISSN: 1432-0827
    Keywords: Dental calculus ; Glycopeptide ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A method is described for the isolation and purification of a sulphated glycopeptide from human supragingival calculus. The compound was isolated after using EDTA treatment, 2 M CaCl2 extraction, proteolytic digestion, ethanol precipitation, and finally purified by DEAE cellulose chromatography. It migrated as a single component on cellulose acetate electrophoresis, and chemical and infrared spectral analysis showed the presence of covalently attached sulphate groups. The sulphated glycopeptide was distinguished from being a sulphated glycosaminoglycan.
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  • 13
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    Calcified tissue international 27 (1979), S. 161-164 
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Ovary ; Rat ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Fifty adult female rats were used to study the effect of 1-alpha-hydroxyvitamin D3 (1α-OH-D3)on bone after oophorectomy. The experimental period was 6 months. At the end of the experiment the femurs and the tibias were investigated for bone mass and composition. Significant signs of osteopenia occurred as a result of oophorectomy. The treatment with 1α-OH-D3 induced only minor changes in blood chemistry but increased bone mass significantly. The findings support the view that 1α-OH-D3 may be a valuable tool in the treatment of osteoporosis resulting from ovarian insufficiency.
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  • 14
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    Calcified tissue international 50 (1992), S. 524-526 
    ISSN: 1432-0827
    Keywords: Verapamil ; Bone ; Osteopenia ; Rat ; Female ; Intestinal calcium absorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Verapamil inhibits the intestinal absorption of calcium (Ca) and increases serum parathyroid hormone in rats. The effects of verapamil on bone tissue after long-term treatment is, however, not well described. Adult female and male Sprague-Dawley rats received verapamil in their drinking water at a dosage of 0.075 mg/ml (low dose) or 0.75 mg/ml (high dose) for 12 weeks; control rats received only drinking water. All rats were fed a diet containing 0.1% Ca and 0.5% P. In female rats, the amount of bone ash per volume was significantly reduced from 0.742 g/ml in controls to 0.713 g/ml after low-dose treatment of verapamil, and to 0.667 g/ml following high-dose treatment (P〈0.01). The tibial length was increased from 39.7 mm in controls to 40.3 mm or to 40.7 mm after low or high doses (P〈0.01). The tibial volume increased from 0.385 ml in controls to 0.397 ml after low doses and to 0.429 ml after high doses (P〈0.01). In contrast, in male rats the amount of bone ash per volume was significantly increased from 0.578 g/ml in controls to 0.580 g/ml after low doses and to 0.620 g/ml after high doses of verapamil (P〈0.01). The tibial bone volume in males as decreased from 0.633 ml in controls to 0.641 ml after low doses and to 0.583 ml after high doses (P〈0.05). The tibial length in the males was not changed by verapamil. The intestinal absorption of Ca was reduced in male rats from 5.28 in controls to 4.03 (serosa/mucosa) after low-dose treatment and to 2.46 after high-dose treatment with verapamil (P〈0.05). In female rats, the intestinal absorption of Ca did not change after verapamil treatment. Thus, chronic treatment with verapamil in female rats induced osteopenia whereas in male rats bone growth was inhibited.
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  • 15
    ISSN: 1432-0827
    Keywords: Rat ; Osteoblast-like culture ; Ovariectomy ; Estrogens ; Bone blood supply
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Ovariectomy in the rat induces a rapid osteopenia associated with an elevated bone turnover. One hundred and twenty-day-old rats were ovariectomized (OVX) or sham-operated (n=6–8 per group and per time period studied). 45Ca accretion rate and bone blood flow (microspheres trapping technique) in the femurs were determined at 28, 42, 84, and 119 days after ovariectomy. Both parameters were markedly increased by 84 days and subsided thereafter. At the 42nd day, when bone turnover was maximal, bone marrow and trabecular bone cultures were obtained from shamoperated and ovariectomized animals (n=10/group). Proliferation rate of bone marrow cells and trabecular osteoblast-like cells estimated by fibroblast colony-forming units (FCFU) efficiency and cell counting was markedly increased in primary and secondary cultures in ovariectomy. These data fitted well with the enhanced number of osteoblasts observed in situ in the long bone metaphyses of estrogen-depleted animals. As estrogens were shown in the literature to inhibit proliferation of the red cell line and of other hemopoietic lines, it is possible that estrogens, through a general mechanism, inhibit hemopoietic and stromal lines and also the proliferation of bone marrow-derived trabecular bone cells.
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  • 16
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    Calcified tissue international 52 (1993), S. 361-364 
    ISSN: 1432-0827
    Keywords: Calcitonin ; Sustained release ; Copolymer depot ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Studies were carried out to determine whether monolithic depot formulations, prepared using lactide:glycolide copolymers, could be used to administer salmon calcitonin (sCT) to rats in vivo. Formulations containing 2, 5, or 10% (w/w) sCT were administered subcutaneously to female Wistar strain rats. Release of sCT was determined by measurement of peptide in plasma using a specific radioimmunoassay and by measurement of residual sCT in the depots after recovery at postmortem. Plasma calcium concentrations and cumulative weight gain of the animals were used to measure pharmacological effects of the released sCT. Release of sCT from the depots was controlled by the copolymer and was sustained for periods up to 10 days. However, the release of sCT from the depots did not significantly alter plasma calcium concentrations, and effects on cumulative weight gain were small and transient. Peptide loading of the formulations was shown to modify sCT release. Maximal release of sCT from depots containing 10% peptide occurred over a 7 to 14-day period postadministration, with 5% sCT release occurred between days 11 and 14, and with 2% sCT, the period of maximal release was between days 11 and 18. Release of peptide from the depots was essentially complete by 21 days postadministration irrespective of the peptide loading. These data suggest that lactide:glycolide copolymer depots may have application for the convenient clinical administration of sCT in metabolic bone diseases.
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  • 17
    ISSN: 1432-0827
    Keywords: Bone ; Nandrolone decanoate ; Ovariectomy ; Bone mechanics ; IGF-I ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Nandrolone decanoate (ND) is an anabolic steroid with a positive effect on bone mass in osteoporotic patients. The mechanism of action, (i.e., reduction of bone resorption and/or Stimulation of bone formation), the ultimate effect on mechanical properties, and the most effective dosage are not yet clear. To address these issues, dose-related effects of the long-term effect of ND on Serum and bone biochemistry, bone mineral content, and bone mechanical properties in ovariectomized (OVX) rats (12 weeks old at the Start of the experiment) were Studied for 6 months. The results were compared with those obtained in agematched, intact, and OVX rats. OVX caused in the femur a significant increase in net periosteal bone formation and net endosteal bone resorption of bone collagen content and torsional strength, and of Serum alkaline phosphatase, osteocalcin, and insulin-like growth factor-I (IGF-I) levels, whereas cortical bone density and calcium/creatinine and phosphorus/creatinine in 24-hour urine were Significantly reduced. Treatment of OVX rats with 1 mg ND/14 days resulted in a Significant increase in periosteal bone formation, femur length, cortical and trabecular bone mineral content and density, torsion stiffness and Strength, and bone IGF-I content, and a decrease in Serum osteocalcin, urinary calcium/creatinine levels, and bone collagen content compared with OVX controls. The higher ND dosage of 2.5 mg/14 days did not improve the results. ND treatment did not reverse all changes induced by OVX to the level of the intact controls. These results indicate that ND acts as an antiresorptive drug and as a bone formation Stimulating drug. Furthermore, the increased bone mass and bone mineral density is associated with improved bone Strength and stiffness and the presence of an increased amount of IGF-I. IGF-I is a growth factor considered to play a role in the maintenance of normal skeletal balance by a paracrine or autocrine mechanism.
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  • 18
    ISSN: 1432-0827
    Keywords: Hyperthyroidism ; Osteopenia ; Bisphosphonate ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Hyperthyroidism, either endogenous or iatrogenic, leads to increased bone turnover and osteopenia. This study was conducted to examine (1) whether thyroid hormone excess in rats causes bone changes similar to those seen in patients with hyperthyroidism, and (2) the effects of the aminobisphosphonate alendronate on the thyroid hormone-induced bone changes. Sprague-Dawley male rats, divided into four groups, received L-thyroxine (T4) 250 μg/kg/day (+T4) or vehicle (-T4) subcutaneously six times per week and alendronate 1.75 mg/kg (+ALN) or vehicle (-ALN) orally twice a week. Rats were sacrificed after 3 weeks of treatment, blood samples were analyzed for serum T4, triiodo-L-thyronine (T3), and osteocalcin, and the proximal tibiae were processed for histomorphometric analysis. Serum T4 and T3 levels measured 20–24 hours after the last injection were 2 to 2.5-fold higher in +T4 groups than in-T4 groups. Serum osteocalcin was significantly (P 〈 0.05) higher in +T4/-ALN group than in the other groups, which were not statistically different from each other. T4 treatment (+T4/-ALN) significantly decreased the amount of cancellous bone volume (-45%) and increased osteoid surface (+254%), osteoblast surface (+111%), and osteoclast surface (+176%) relative to control values. Alendronate increased the bone volume above control values in both T4-treated (+ T4/ +ALN) and untreated (-T4/ +ALN) rats, and prevented the T4-induced increase in bone turnover in +T4/+ALN rats. It is concluded that (1) excess thyroid hormone induces cancellous bone loss associated with high bone turnover in the rat, and (2) this bone loss can be prevented by alendronate through the inhibition of osteoclastic activity.
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  • 19
    ISSN: 1432-0983
    Keywords: Ribosomal protein ; Immunological homology ; Yeast ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Polyclonal antibodies raised against ribosomal protein (r-protein) L2 of Schizosaccharomyces pombe were used to check for cross-reaktions with total r-proteins of rat liver. Using this procedure, the rat liver r-proteins, L4 and L24, were identified as being immunologically related to yeast L2. In addtional, homologies between rat liver L4 and L24 were detected. The possible implications for the regulation of r-protein synthesis are discussed.
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  • 20
    ISSN: 1432-0975
    Keywords: Key words Otolith ; Chemistry ; ICP-MS ; Stock discrimination ; Epinephelus striatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract  We examined the utility of otolith minor and trace element chemistry, assayed with inductively coupled plasma mass spectrometry (ICP-MS), as a means of delineating population structure in the Nassau grouper (Epinephelus striatus). We characterized the elemental composition of otoliths collected in 1993 from three locations in Exuma Sound, Bahamas and from Glover Reef, Belize in 1995. A single location in Exuma Sound was sampled in 1994 to test temporal variability in otolith composition. Five elements (Ca, Zn, Sr, Ba and Pb) were routinely detected, at levels significantly above background, by solution-based ICP-MS. Results from analysis of variance of elemental data, expressed as a ratio to Ca, indicated that there were no significant differences among the Exuma locations for any element, but significant variability was found between Glover Reef and the pooled Exuma localities for Zn/Ca, Sr/Ca and Ba/Ca ratios. Significant inter-annual differences at one Exuma Sound location was restricted to Ba/Ca ratios. Discriminant function analysis correctly classified 86% and 95% of the Belize and pooled Exuma sites, respectively. Otoliths from Belize were characterized by low Zn/Ca and high Ba/Ca and Pb/Ca ratios compared to otoliths from fish collected in Exuma Sound. Although differences in Ba levels may be related to upwelling at Glover Reef, more data are needed to definitely link otolith composition with regional differences in water chemistry.
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    Journal of molecular evolution 15 (1980), S. 79-101 
    ISSN: 1432-1432
    Keywords: Molecules ; Interstellar ; Chemistry ; Isotopes ; Solar system
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    Topics: Biology
    Notes: Summary The study of interstellar molecules broadly includes two areas of interest. One area uses the unique ability of molecules to act as probes of the physical conditions in the cold, dense, visually opaque component of the interstellar medium. The physical properties of this and other components of the interstellar medium are summarized. The other area deals with the chemistry of interstellar molecules, recent aspects of which are emphasized in this review. Gas-phase chemistry, shock chemistry, and grain surface chemistry are discussed in the context of recent observations. No present observations suggest that surface reactions are relevant, but neither can they be ruled out. Ion-molecule reactions are clearly operative, at least for the simpler species. Chemical isotope fractionation is reviewed, andd it is concluded that the complexities of the chemistry allow no cosmological conclusions to be drawn from observations of deuterium in interstellar molecules, while the presence of13C in interstellar molecules permits an estimate of the12C/13C ratio which is consistent with the current concepts of the nucleosynthesis history of the Galaxy. Possible connections between interstellar molecules and the early molecular history of the solar system are discussed.
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  • 22
    ISSN: 1432-1432
    Keywords: Carcinoembryonic antigen ; Evolution ; Gene family ; Human ; Rat ; Synonymous substitutions ; Silent molecular clock ; Evolutionary trees
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    Topics: Biology
    Notes: Summary Various rodent and primate DNAs exhibit a stronger intra- than interspecies cross-hybridization with probes derived from the N-terminal domain exons of human and rat carcinoembryonic antigen (CEA)-like genes. Southern analyses also reveal that the human and rat CEA gene families are of similar complexity. We counted at least 10 different genes per human haploid genome. In the rat, approximately seven to nine different N-terminal domain exons that presumably represent different genes appear to be present. We were able to assign the corresponding genomic restriction endonuclease fragments to already isolated CEA gene family members of both human and rat. Highly similar subgroups, as found within the human CEA gene family, seem to be absent from the rat genome. Hybridization with an intron probe from the human nonspecific cross-reacting antigen (NCA) gene and analysis of DNA sequence data indicate the conservation of noncoding regions among CEA-like genes within primates, implicating that whole gene units may have been duplicated. With the help of a computer program and by calculating the rate of synonymous substitutions, evolutionary trees have been derived. From this, we propose that an independent parallel evolution, leading to different CEA gene families, must have taken place in, at least, the primate and rodent orders.
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    Journal of molecular evolution 33 (1991), S. 442-449 
    ISSN: 1432-1432
    Keywords: Humans ; Mouse ; Rat ; Codon usage ; Mutation bias ; Selection
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    Topics: Biology
    Notes: Summary A new statistical test has been developed to detect selection on silent sites. This test compares the codon usage within a gene and thus does not require knowledge of which genes are under the greatest selection, that there exist common trends in codon usage across genes, or that genes have the same mutation pattern. It also controls for mutational biases that might be introduced by the adjacent bases. The test was applied to 62 mammalian sequences, the significant codon usage biases were detected in all three species examined (humans, rats, and mice). However, these biases appear not to be the consequence of selection, but of the first base pair in the codon influencing the mutation pattern at the third position.
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  • 24
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    Journal of comparative physiology 170 (1992), S. 645-650 
    ISSN: 1432-1351
    Keywords: Milk ejection reflex ; Positive pressure oscillations ; Motor activity of pups ; Tactile stimulation of nipples ; Rat
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    Topics: Biology , Medicine
    Notes: Summary Changes of positive pressure exerted by pups on nipples during sucking were investigated using anesthetized, lactating dams. It was found that, every 50–60 s, individual pups performed bouts of pressure oscillations (3/s) of high amplitude which lasted about 10–12 s and coincided with periods of increased motor activity. During the intervals, when pups were quiet, series of low-amplitude oscillations (3/s) were also observed. Using a strain measuring method to record the activity of sucking pups, synchronization of activity of two or more pups was found to occur periodically every 25–30 s and, most frequently, 10–30 s before the reflex increase of milk pressure. In further experiments, artificial tactile stimulation was applied to the dam's nipples using the joint action of suction and positive pressure. Following a short-term (10–20 s) increase in frequency and amplitude of artificial nipple stimulation, 60%–80% of all reflexive peaks of milk pressure were elicited with a latency of 19 ± 5 s. This suggests that there are specific conditions under which the stimulation of nipples by pups may trigger the formation of the milk ejection reflex in the rat.
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    Journal of comparative physiology 171 (1992), S. 657-664 
    ISSN: 1432-1351
    Keywords: Inferior olivary complex ; Cerebellum ; 3-acetylpyridine ; Harmaline ; Learning ; Memory ; Rat
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    Topics: Biology , Medicine
    Notes: Summary DA/HAN-strained male rats (pigmented rats) were submitted to two experimental tasks consisting of spatial learning (water-escape) and a passive avoidance conditioning. Both these tasks were performed by different animals. In order to destroy the inferior olivary complex, the animals were injected with 3-acetylpyridine either 9 days prior to the initial learning session or 24 h after completion of the learning task. They were retested (retrieval test) 10 days after the initial learning was achieved. Learning and retention were compared to those noted in control rats. Administration of 3-acetylpyridine before the initial learning did not prevent the spatial learning but the scores were greatly altered and the number of trials needed to reach the fixed learning criterion was much greater than in controls. However, 10 days later the animals had memorized their initial experience. Injection of 3-acetylpyridine after the initial learning session impaired memory: the animals had completely forgotten their initial learning. It can therefore be concluded that lesion of the afferent climbing fibres to the cerebellar cortex alters learning and retention of a spatial task. Such a lesion does not interfere with learning and retention of a passive avoidance conditioning, since in this condition the experimental animals injected with 3-acetylpyridine either before or after the initial learning behave similarly to controls. The effects of the inferior olivary complex lesion are obviously different according to the task to be learnt, suggesting that these two tasks do not require the integrity of the same nervous structures.
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    Journal of molecular evolution 24 (1987), S. 260-271 
    ISSN: 1432-1432
    Keywords: Mouse ; Rat ; Two-dimensional electrophoresis ; Quantitative variability of proteins ; Qualitative variability of proteins ; Protein classes ; Membrane proteins ; Organ-specific proteins ; Regulatory genes ; Speciation
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    Topics: Biology
    Notes: Summary Proteins of membranes and cytosols were extracted from the livers and brains of mice (inbred strain DBA/6J) and rats (inbred strain DA/Han) and separated by two-dimensional electrophoresis (2-DE). The 2-DE patterns were compared with regard to qualitative (spot position) and quantitative (spot intensity) characteristics of the proteins of these two species. The following results were obtained: (1) Brain had more (higher percentage) conservative proteins (proteins found in both mice and rats) than liver; (2) plasma membranes had more conservative proteins than the cytosols; (3) organ-unspecific proteins contained more conservative proteins than relatively organ-specific proteins; (4) the pattern of distribution of genetic variability among different classes of proteins represented by findings 1–3 was the same for the qualitative and quantative characteristics of the proteins; and (5) some observations indicated that quantitative variability occurred more frequently among proteins than did qualitative variability. Our conclusion is that regulatory sequences in the DNA (regulatory genes) are subjected to functional constraints that differ in strength among different classes of proteins by the same ratios as the constraints acting on the structural genes. The overall effect of the selective pressure is, however, less stringent for regulatory genes than for structural genes. The results obtained here by comparing two different species are very similar to previous results we obtained by studying different subspecies (inbred strains of the mouse). From this finding arises a new concept: the study of molecular evolution on the basis of different classes of proteins. Our results were compared with data from the literature that were obtained in part from studies on cultured cells. The comparison suggested that cultured cells have lost their tissue-specific proteins, and so generate predominantly extremely conservative proteins.
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    European journal of nutrition 26 (1987), S. 43-51 
    ISSN: 1436-6215
    Keywords: Dietary protein ; Vitamin A ; Rat
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    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Es wurde der Einfluß von Qualität und Quantität von Nahrungsproteinen auf die Verteilung einer einzigen massiven Dosis von Vitamin A in verschiedenen Organen wachsender Wistar-Ratten untersucht. Die Untersuchungen wurden mit Casein- und Bengal-Gram-Diäten mit 20 % und 10 % Proteingehalt und auch mit radioaktiv markiertem Retinylacetat durchgeführt. Die Ergebnisse zeigen, daß die Leberspeicherung sowohl von Vitamin A aus der Nahrung als auch die einer einzigen starken Vitamin-A-Gabe (20 000 I.U.) stark herabgesetzt war bei Ratten, die nach der Bengal-Gram-Diät gefüttert wurden, verglichen mit Ratten, die auf Casein-Diät gesetzt waren. Im Gegensatz zur Leberspeicherung ist das Vitamin-A-Niveau im Plasma in allen Gruppen vergleichbar. Füttern niedriger Protein-Qualität reduzierte die Gewebeverteilung von [3H]-Retinylacetat sowohl bei Kontrollratten als auch bei solchen, denen eine massive Dosis Vitamin A gegeben wurde. Diese Untersuchung läßt vermuten, daß sowohl schlechte Qualität als auch unzureichende Mengen von Nahrungsproteinen nachteilige Einflüsse auf den Vitamin-A-Zustand wachsender Ratten haben.
    Notes: Summary The influence of the quality and the quantity of dietary proteins on the distribution of a single massive dose of vitamin A in various organs of growing Wistar strain rats has been studied by using casein and bengal gram diets at 20 % and 10 % protein levels. The distribution of [3H]-retinyl acetate in various tissues was also investigated in these dietary conditions. The results show that the hepatic storage of dietary as well as a single massive dose (20,000 I.U.) of vitamin A was profoundly decreased in the rats fed on bengal gram diets as compared to those fed on casein diets. Regardless of hepatic stores, the plasma vitamin A levels were comparable in all the groups. Feeding of low quality of protein reduced the tissue distribution of [3H]-retinyl acetate in control as well as rats given a massive dose of vitamin A. This study suggests that both the poor quality and the inadequate quantity of dietary protein are detrimental influences on the vitamin A status of the growing rats.
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    Mycopathologia 123 (1993), S. 149-154 
    ISSN: 1573-0832
    Keywords: Ascending pyelonephritis ; Candida albicans ; Experimental model ; Rat
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    Topics: Biology , Medicine
    Notes: Abstract We developed a new experimental model of ascendingCandida pyelonephritis in female rats with leukopenia and vesicoureteral reflux. Rats were treated transperitoneally with cyclophosphamide (200 mg/kg) to induce leukopenia 3 days before and transurethrally with diluted acetic acid solution to induce vesicoureteral reflux 1 day before inoculation ofCandida albicans strain, ATCC 10259 (containing 107 cells). Microscopy revealed acute pyelonephritis in whichCandida cells invaded from the fornix and/or papilla into the medulla within 3 days after inoculation. Between 7 and 28 days after inoculation, chronic pyelonephritis reached the cortex. The incidence of pyelonephritis increased gradually and was approximately 80% after 7 days.Candida colony counts of bladder urine specimens obtained by direct puncture were significantly greater in rats with pyelonephritis extending into the parenchyma than in those with pyelonephritis located along the pelvis (p〈0.01). These results suggest that this rat model shows the characteristic feature of ascending pyelonephritis due toC. albicans and that the severity ofCandida pyelonephritis can be estimated fromCandida counts of bladder urine.
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    Mycopathologia 55 (1975), S. 53-55 
    ISSN: 1573-0832
    Keywords: Rubratoxine B ; Mitochondria ; Rat
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    Topics: Biology , Medicine
    Notes: Abstract The in vitro effect of rubratoxin B on the electron transport system of rat liver mitochondria was investigated. This mycotoxin depressed oxygen consumption in ADP-lacking mitochondria and in ADP-coupled mitochondria, using succinate or β-hydroxybutyrate as substrats. Rubratoxin B is neither an oxidative-phosphorylation inhibitor nor uncoupling agent. Its effect is compared with aflatoxin B1.
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  • 30
    ISSN: 1573-0603
    Keywords: Endothelial cells ; Isolation ; Culture ; Mesentery ; Rat ; Rabbit
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    Topics: Biology
    Notes: Abstract Methods are described for the enzymatic isolation of endothelial cells from rat and rabbit mesenteric arteries and veins. The mesenteric vascular bed is incubated with an enzyme solution containing collagenase, deoxyribonuclease, papain, dithiothreitol and bovine serum albumin for 45 min at 37 °C in a shaking waterbath. After the 45 min digestion, cells are centrifuged and plated. This method yields an endothelial cell population with a high plating efficiency which is relatively free of smooth muscle contamination.
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    ISSN: 1573-0603
    Keywords: Brain ; Histology ; Organotypic culture ; Patch clamp recording ; Rat
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    Topics: Biology
    Notes: Abstract The goal of the current research was to define an in vitro system that can replace in vivo experimentation but reflects as far as possible aspects of the intact situation of the developing nervous system of mammals. Tissue slices of postnatal rat hippocampi were continuously moved between the medium and gas phase. Under these conditions the complex cytoarchitecture was preserved for many weeks. Lactate dehydrogenase assay, cell size analysis and neuron- and glial cell specific immunocytochemical markers were employed to illuminate explant development in vitro. By scanning electron microscopy the explant surface was analysed in order to determine the conditions suitable for patch clamp recording. Electrophysiological analysis revealed a pronounced spontaneous activity showing the neurons to be functionally active. These data indicate that organotypic roller cultures reflect to a large extent the in vivo situation of the mammalian nervous system. The culture system provides a promising model system for developmental physiology, neurotoxicology and pharmacology.
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    Journal of biomedical science 1 (1994), S. 201-203 
    ISSN: 1423-0127
    Keywords: Hypertension ; Eicosanoid ; Rat ; Genetics ; Kidney
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    Topics: Biology , Medicine
    Notes: Abstract The present paper reviews the evidence for a possible involvement of renal eicosanoids in the pathophysiology of high blood pressure in genetically hypertensive rats of the Lyon strain. Both in vivo and in vitro experiments suggest that an increased ability to synthesize the vasoconstrictor prostaglandin H2 and/or thromboxane A2 in renal vessels (1) acts as an autocrine amplifier of pressor agents and (2) may contribute to resetting the pressure natriuresis curve which is a prerequisite for the development and maintenance of hypertension.
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    Development genes and evolution 194 (1985), S. 429-432 
    ISSN: 1432-041X
    Keywords: Tail bud ; Tail gut ; Gut ; Organogenesis ; Rat
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    Topics: Biology
    Notes: Summary The formation of the tail portion of the primitive gut was investigated by light and electron microscopy in 10- and 11-day rat embryos. The observations permit the conclusion that the tail gut does not form as a posterior extension of the hindgut but originates from the tail bud mesenchyme by mechanism analogous to the secondary neurulation. It includes cell condensation, aquisition of apicobasal polarity and the radial, rosette-like arrangement around a central cavity. These cells bear the cytological characteristics of both the absorptive epithelial cells and the mesenchymal cells at their apical (adluminal) and abluminal ends respectively.
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    Pure and applied geophysics 118 (1980), S. 128-151 
    ISSN: 1420-9136
    Keywords: Galactic cosmic rays ; Solar proton events ; Particle precipitation ; Chemistry
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    Topics: Geosciences , Physics
    Notes: Abstract An assessment is made of the relative contribution of certain classes of energetic particle precipitation to the chemical composition of the middle atmosphere with emphasis placed on the production of odd nitrogen and odd hydrogen species and their subsequent role in the catalytic removal of ozone. Galactic cosmic radiation is an important source of odd nitrogen in the lower stratosphere but since the peak energy deposition occurs below the region where catalytic removal of O3 is most effective, it is questionable whether this mechanism is important in the overall terrestrial ozone budget. The precipitation of energetic solar protons can periodically produce dramatic enhancement in upper stratospheric NO. The long residence time of NO in this region of the atmosphere, where catalytic interaction with O3 is also most effective, mandates that this mechanism be included in future modelling of the global distribution of O3. Throughout the mesosphere the precipitation of energetic electrons from the outer radiation belt (60°≲Λ≲70°) can sporadically act as a major local source of odd hydrogen and odd nitrogen leading to observable O3 depletion. Future satellite studies should be directed at simultaneously measuring the precipitation flux and the concomitant atmosphere modification, and these results should be employed to develop more sophisticated models of this important coupling.
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  • 35
    ISSN: 1420-9071
    Keywords: Rat ; cerebrospinal fluid, human ; analgesia ; naloxone ; pain indifference, congenital ; opiates, endogenous
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    Topics: Biology , Medicine
    Notes: Summary CSF from a patient with congential indifference to pain was found to produce analgesia in the rat following intracerebroventricular injections. The analgesic effect was attenuated by pretreatment with naloxone suggesting the involvement of hyperactive endogenous opiate mechanisms in this patient.
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    Cellular and molecular life sciences 40 (1984), S. 1368-1369 
    ISSN: 1420-9071
    Keywords: Rat ; kidney ; hypertensive ; prostaglandin dehydrogenase ; hexokinase
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    Topics: Biology , Medicine
    Notes: Summary 15-Hydroxyprostaglandin dehydrogenase (PGDH) surged in hypertensive (SHR) and normotensive (WKY) rat kidney at 8 days of age, is greatest in SHR. Hexokinase fell in SHR at 17 days of age, but thereafter was similar to WKY. This suggests multisystem enzymatic abnormalities in SHR kidney during development of hypertension.
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  • 37
    ISSN: 1420-9071
    Keywords: Rat ; alloxan diabetes ; intestinal villus ; alkaline phosphatase ; sucrase ; epithelial cells ; villus-crypt axis
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    Topics: Biology , Medicine
    Notes: Summary The sucrase activity in enterocytes isolated from the villus crypt axis was found to increase in all regions of the villus from day 2 after induction of diabetes, and the increase continued until day 4. In contrast, alkaline phosphatase activity increased mainly in the apical one-third of the villus-crypt column, and the increase occurred abruptly on day 4 with increase in food intake.
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    Cellular and molecular life sciences 42 (1986), S. 169-171 
    ISSN: 1420-9071
    Keywords: Rat ; olfactory pathway selective lesions ; plasma corticosterone ; lactacidemia ; adrenal glands
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    Topics: Biology , Medicine
    Notes: Summary In comparison to control rats, basal plasma corticosterone level and lactacidemia significantly increased in rats submitted to a bilateral lesion of the lateral olfactory tract and/or the anterior branch of the anterior commissure. Only the anterior branch of the anterior commissure induced hyperglycemia; that of the lateral olfactory tract exerted an opposite effect.
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    Aquatic sciences 51 (1989), S. 108-128 
    ISSN: 1420-9055
    Keywords: Chemistry ; mountain lakes ; silica ; acidity ; sediment
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    Topics: Biology
    Notes: Abstract Alpine lakes in siliceous catchments of Tyrol and Carinthia (Austria) show signs of acidification. About 9% of the studied lakes have no alkalinity, more than 20% are below pH 6. About two thirds of all lakes have acid neutralizing capacities below 100 μeq 1−1. In spite of moderate precipitation acidity, some lakes show considerable concentrations of dissolved reactive aluminum during or shortly after snowmelt. High altitude lakes of the Alps are definitely more acidic than high mountain lakes in remote areas. Large differences in water and soil chemistry of nearby situated lakes were attributed to heterogeneities of bedrock geology. Paleolimnological investigations on former pH values of five lakes, based on diatom assemblages in the sediment, showed different developments: recent and past acidification, stable conditions, and alkalinization.
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    Accreditation and quality assurance 5 (2000), S. 409-413 
    ISSN: 1432-0517
    Keywords: Key words Metrology ; Comparisons ; Chemistry ; Standards
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    Topics: Chemistry and Pharmacology
    Notes: Abstract  After stressing the importance in the modern world of accurate and reproducible measurements, the actions taken by the Bureau International des Poids et Mesures to set up, together with the regional metrology organizations, a series of key comparisons are described. They are the technical foundation of a mutual recognition of national measurement standards arrangement prepared in conjunction with the National Metrology Institutes (NMIs). This arrangement also includes the recognition of calibration and measurement certificates issued by these institutes. Then, the consequences of this arrangement for trade are described. The case of chemical analysis is illustrated by the application of the Kyoto protocol on the reduction of greenhouse gases. But the global workload to be taken up by the International Committee of Weights and Measures, its Consultative Committee for Amount of Substance and the NMIs is huge.
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  • 41
    ISSN: 1432-041X
    Keywords: Inner cell mass ; Blastocyst ; Morula ; Implantation ; Rat
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    Topics: Biology
    Notes: Summary The number of trophectoderm (TE) and inner cell mass (ICM) cells was determined by complementmediated lysis and differential staining in rat embryos collected at different times during in vivo preimplantation development. At 90 h after fertilization, two groups of morulae were discriminated according to the presence or absence of detectable ICM cells, and the analysis of their total cell number indicated that acquisition of a permeability seal between TE cells begins at the 14-cell stage. On the other hand, our data confirmed that blastocoele formation occurs after the fourth cleavage division in the rat. The total cell number increased exponentially with time in blastocysts recovered between 90 h and 127 h but the cell kinetics of TE and ICM cells were different. The proportion of ICM cells consequently varied throughout blastocyst development, with a peak value for expanded blastocysts at 103 h. Finally, a linear-quadratic relationship was found between the numbers of TE and ICM cells when all the embryos with a detectable ICM were analysed together.
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    Cellular and molecular life sciences 40 (1984), S. 1008-1010 
    ISSN: 1420-9071
    Keywords: Rat ; ethanol preference ; acetaldehyde self-administration
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    Topics: Biology , Medicine
    Notes: Summary Peripherally self-injected acetaldehyde in interaction with environmental and nutritional variables significantly enhances alcohol drinking in rats and suggests an involvement of acetaldehyde in voluntary alcohol intake.
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    Cellular and molecular life sciences 41 (1985), S. 273-275 
    ISSN: 1420-9071
    Keywords: Rat ; embryo ; embryo ; rat ; β-hydroxybutyrate ; diabetes ; maternal ; fetal malformation ; malformation ; fetal ; ketone bodies
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    Topics: Biology , Medicine
    Notes: Summary In order to investigate further the relationship between maternal diabetes and fetal malformation, rat embryos were grown in vitro in the presence of β-hydroxybutyrate, one of the ketone bodies produced by diabetics. At 10 mM, β-hydroxybutyrate produced minor abnormalities and at 20 mM it produced major abnormalities in rat embryos.
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    Calcified tissue international 14 (1974), S. 283-289 
    ISSN: 1432-0827
    Keywords: Sodium fluoride ; Osteoporosis ; Bone ; Strength ; Rat
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    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'utilisation thérapeutique de fluorure de sodium a été recommandée dans le traitement de diverses maladies osseuses ostéopéniques. Cet emploi est basé principalement sur les effects ostéosclérotiques bien connus du fluorure de sodium, mais on connait mal son effet sur la force de résistance osseuse. L'influence de diverses concentrations de fluorure de sodium sur la force de résistance osseuse de jeunes rats soumis à des régimes riches et pauvres en calcium a été étudiée. L'administration de fluorure de sodium augmente le diamètre osseux, indiquant une stimulation de la formation de l'os périosté, mais la force de résistance osseuse est réduite ou non modifiée par l'ingestion de fluor.
    Abstract: Zusammenfassung Die therapeutische Verwendung von Natriumfluorid ist für eine Anzahl von Knochenmangel-Krankheiten empfohlen worden. Die Empfehlungen basieren hauptsächlich auf den bekannten osteosklerotischen Wirkungen von Natriumfluorid; über dessen Effekt auf die Knochenstärke ist wenig bekannt. In dieser Arbeit wurde der Einfluß verschiedener Konzentrationen von Natriumfluorid auf die Knochenstärken von wachsenden Ratten mit hoher und niederer Calciumeinnahme untersucht. Die Verabreichung von Natriumfluorid erhöhte den Knochendurchmesser, was auf eine Stimulierung der Periostbildung hinwies, die Knochenstärke wurde jedoch durch Fluorideinnahme herabgesetzt oder nicht beeinflußt.
    Notes: Abstract The therapeutic use of sodium fluoride has been recommended in a variety of osteopenic bone diseases. The recommendations are based mainly on the known osteosclerotic effects of sodium fluoride and little information is available as to its effect on bone strength. The influence of various concentrations of sodium fluoride on bone strength in growing rats on high and low calcium diets was studied. The administration of sodium fluoride increased bone diameter, indicating stimulation of periosteal bone formation, but bone strength was reduced or not affected by fluoride ingestion.
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    Calcified tissue international 13 (1973), S. 113-129 
    ISSN: 1432-0827
    Keywords: Kinetics ; Growth ; Epiphyses ; Hypophysectomy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La largeur de la métaphyse tibiale, la zone indifférenciée, la zone sériée et les cellules en dégénerescence ont été observées chez des rats Sprague-Dawley normaux et hypophysectomisés. La production cellulaire de la métaphyse est déterminée sur la base de la croissance osseuse longitudinale déterminée par l'oxytétracycline et la taille des cellules en dégénérescence. La diminution de la croissance osseuse longitudinale, en fonction de l'augmentation de l'âge et après hypophysectomie, est due partiellement, à la diminution de production cellulaire et partiellement à une décroissance de la taille des cellules en dégénérescence dans la métaphyse. L'influence de la production cellulaire et de l'activité mitotique prédomine.
    Abstract: Zusammenfassung Die Breite der proximalen Wachstumsplatte der Tibia, deren undifferenzierter und säulenförmiger Zone und die Größe der nahe bei der Metaphyse auftretenden degenerativen Zellen wurden in normalen und hypophysektomierten Sprague-Dawley-Ratten bestimmt. Die Zellproduktion in der Wachstumsplatte wurde aus dem longitudinalen Knochenwachstum berechnet, welches mittels Oxytetracyclin und der Größe der degenerativen Zellen bestimmt wurde. Es wurde festgestellt, daß die Abnahme des longitudinalen Knochenwachstums bei zunehmendem Alter und nach Hypophysektomie zum Teil einem Rückgang in der Zellproduktion, zum Teil einer Verminderung der Größe der degenerativen Zellen in der Wachstumsplatte zuzuschreiben ist. Der Einfluß der Zellproduktion, und somit der mitotischen Aktivität, herrscht vor.
    Notes: Abstract The width of the proximal growth plate of the tibia, its undifferentiated and columnar zone and the size of the degenerative cell close to the metaphysis, were determined in normal and hypophysectomized Sprague-Dawley rats. The cell production in the growth plate was calculated from the longitudinal bone growth determined with oxytetracycline and the degenerative cell size. It was found that the decrease in longitudinal bone growth with increasing age and after hypophysectomy, is due partly to a decrease in cell production, and partly to a decrease in degenerative cell size in the growth plate. The influence of cell production and thus the mitotic activity predominates.
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  • 46
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    Calcified tissue international 14 (1974), S. 3-14 
    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Mineral ; Phase ; Chemistry ; Synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des diagrammes de phase d'équilibre ont été déterminés pour le système CaO-P2O5-H2O en utilisant des techniques de synthèse hydrothermique au cours de variatio nsde température allant de 300–600° et 2 Kb H2O de pression. De l'hydroxyapatite bien cristallisé a été synthétisé et caractérisé. De faibles variations de paramètres de la maille cristalline, liées à la température de synthèse et composition globale du matériel initial, ont été déterminées. Des conditions chimiques précises sont nécessaires pour obtenir de l'apatite, en tant que seule phase solide en équilibre dans la solution. Les résultats de diagramme de phase d'équilibre sont comparés avec ceux obtenus dans des milieux synthétiques.
    Abstract: Zusammenfassung Es wurden Gleichgewichts-Phasendiagramme für das System CaO-P2O5-H2O bestimmt, indem hydrothermale Synthese-Techniken im Temperaturbereich von 300–600° und bei einem Druck von 2 Kb H2O verwendet wurden. Es wurde gut-kristallisiertes Hydroxyapatit erzeugt und charakterisiert. Es wurden geringe Unterschiede in den Parametern der Zelleinheiten festgestellt, welche von der angewandten Temperatur und der Zusammensetzung des Startmaterials abhingen. Es waren genaue chemische Bedingungen nötig, um Apatit als die einzige feste Phase im Gleichgewicht mit der Lösung zu erhalten. Die Resultate der Gleichgewichts-Phasendiagramme werden mit früheren Untersuchungen mit der Synthesetechnik verglichen.
    Notes: Abstract Equilibrium phase diagrams have been determined for the system CaO-P2O5-H2 using hydrothermal synthesis techniques in the temperature range 300–600° and 2 Kb H2O pressure. Well-crystallized hydroxyapatite has been produced and characterized. Small variations in unit cell parameters dependent on temperature of synthesis and bulk composition of the starting materials have been determined. Precise chemical conditions were required to obtain apatite as the only solid phase in equilibrium with solution. Equilibrium phase diagram results are compared with previous synthetic investigations.
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  • 47
    ISSN: 1432-0827
    Keywords: Rat ; Calvarium ; Electron microscopy ; Preosteoclasts ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This is a study of the fine structure of cells of the 20-day fetal rat calvarium. Special attention is given to identifying and characterizing preosteoclasts. These cells are relatively common and located largely, but not exclusively, at the endocranial bone surface. The preosteoclasts are characterized by abundant mitochondria, an incomplete perinuclear Golgi apparatus, and variable-shaped dense granules. The dense granules are unique in appearance in that they contain an internal dense matrix surrounded by a clear halo. Most granules are circular in shape but some are elongate or tubular in form. Granules with identical appearance are observed in osteoclasts. The preosteoclasts are mononucleate, or occasionally binucleate. It is suggested that because preosteoclasts are morphologically distinctive and relatively abundant, it should be feasible to separate these cells from a heterogeneous cell isolate.
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  • 48
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    Calcified tissue international 34 (1982), S. 211-213 
    ISSN: 1432-0827
    Keywords: Rat ; incisor ; ameloblasts ; enamel ; 45Ca autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Rats were injected with45Ca and horseradish peroxidase to determine the patterns of45Ca incorporation into incisor enamel and the morphological types of the overlying maturation ameloblasts.45Ca autoradiography showed no differences in the patterns of incorporation into enamel between routinely embedded and freeze-dried specimens. Enamel overlaid by ruffle-ended ameloblasts was much more heavily labeled while that overlaid by smooth-ended ameloblasts showed only moderate labeling. The observations lend further support to the hypothesis that the ruffle-ended cells are very active in mineralizing enamel and that the smooth-ended cells are in a passive, restorative phase.
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  • 49
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    Calcified tissue international 51 (1992), S. 137-142 
    ISSN: 1432-0827
    Keywords: Swimming exercise ; Bone histomorphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To specify the exercise-induced changes on different skeletal sites, the effect of a 5-week endurance swin training was studied in rats. Eighteen Lyon strain (Sprague-Dawley) 5-week old female rats were divided into nine sedentary and nine swimming rats. Each swim training session was increased by 15 minutes from 2–6 hours per day. A histomorphometric study was performed at the primary and secondary spongiosa of the distal femur and at the secondary spongiosa of lumbar and thoracic vertebral bodies. After training, bone loss was observed in the secondary spongiosa of lumbar vertebral bodies (24.7%) and in the primary spongiosa of distal femur (15.2%). A tendency to bone loss was also detected in the secondary spongiosa of distal femur (10.8%), whereas no change was detected in thoracic vertebral bodies. In secondary spongiosa, bone loss was accompanied with a thinning of trabeculae. Total eroded surfaces and osteoid surfaces were significantly decreased in the three studied skeletal sites, suggesting a decreased bone turnover. The decreased thickness of osteoid seams in both lumbar vertebrae and distal femur could mean that the osteoblastic activity has also been altered at the cell level, leading to thinning of trabeculae. Five-week swim training with such duration and intensity of exercise appears unable to increase bone volume in rats and, therefore, causes adverse effects. The three studied bones seemed to adapt differently to experimental conditions. The lack of ground reaction forces induced by water immersion might have contributed to the observed bone loss. “Normal” gravity would be an important cofactor in the osteogenic effects of exercise.
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  • 50
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    Calcified tissue international 7 (1971), S. 150-162 
    ISSN: 1432-0827
    Keywords: Uranium ; Bone ; Distribution ; Fission ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une concentration moyenne de 2.4×10−8 g U/g de cendre a été obtenue à partir de l'os humain normal. La microdistribution de l'uranium dans l'os indique que cet élément est surtout limité à surface de l'endoste et, en particulier, aux surfaces de l'os lamellaire et aux parois des canaux de Havers, ouverts dans l'os corticol. Cette répartition suggère que l'uranium se présente sous une forme chimique impropre à son incorporation dans l'apatite osseux: il ne semble donc pas exister une distribution diffuse significative de l'uranium dans l'os.
    Abstract: Zusammenfassung Eine mittlere Konzentration von 2,4×10−8 g Uran/g Asche wurde in normalen menschlichen Knochen gefunden. Die Feinverteilung von Uran im Knochen zeigt, daß dieses Element hauptsächlich an der endostalen Oberfläche vorkommt, insbesondere an der Oberfläche des trabeculären Knochens und an den Wänden der offenen Haversschen Kanäle im kortikalen Knochen. Diese Verteilung läßt vermuten, daß Uran in einer chemischen Form vorliegt, welche sich für den Einbau in das Knochenapatit nicht eignet. Daraus folgt, daß keine signifikante diffuse Verteilung des Urans innerhalb des Knochens vorliegt.
    Notes: Abstract A mean concentration of 2.4×10−8 g U/g ash has been obtained for normal human bone The microdistribution of uranium in bone indicates that this element is mainly restricted to endosteal surfaces; in particular the surfaces of trabecular bone and the walls of open Haversian canals in cortical bone. This distribution suggests that uranium is present in a chemical form that is not acceptable for incorporation into bone apatite and consequently there does not appear to be a significant diffuse distribution of uranium throughout bone.
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  • 51
    ISSN: 1432-0827
    Keywords: Morphology ; Glycosaminoglycans ; Cartilage ; Chemistry ; Audioradiography ; Healing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Une perte de substance ostéo-cartilagineuse, de taille limitée et identique, est réalisée chez le lapin adulte et la cicatrisation est étudiée histologiquement et par autoradiographie après marquagein vitro au35S-sulfate. Une analyse microchimique est pratiquée pour le contenu et la composition en glycosaminoglycanes. 1. Entre la première semaine et la 4ème et 8ème semaine, un tissu conjonctif non-métachromatique se différencie en un cartilage métachromatique et la quantité de sulfate de chondroitine augmente de façon significative aux dépens des glycoprotéines. 2. Jusqu'à la 4ème semaine, la perte de substance est surtout comblée par de l'os néoformé: après cette période, la région est comblée au delà de la limite de la surface articulaire. 3. Le cartilage hyalin, ressemblant morphologiquement, autoradiographiquement et chimiquement au cartilage articulaire, en ce qui concerne la distribution en glycosaminoglycanes, constitute la surface articulaire de la perte de substance comblée dans un tiers des cas après 8 semaines. Le cartilage hyalin s'observe surtout dans les régions où de l'os néoformé a comblé la cavité médullaire. 4. Dans les deux tiers des cas, après 8 semaines, les surfaces articulaires des zones comblées comportent, non seulement du cartilage, mais aussi du tissu fibreux se formant essentiellement sur les parties latérales et dans les régions, où la cavité médullaire, fliant face, à la surface articulaire, n'a pas été comblée par du tissue osseux. La fraction glycoprotéique augmente par rapport à la fraction chondroitine sulfate. 5. Dans la majorité des cas, après 20 semaines, le cartilage néoformé subit des phénomènes dégénératifs, qui se traduisent par une diminution en chondroitine sulfate.
    Abstract: Zusammenfassung Bei ausgewachsenen Kaninchen wurde ein begrenzter, standardisierter, osteochondraler Defekt hervorgerufen, und das regenerierte Gewebe wurde histologisch und autoradiographisch durch Markierung in vitro mit35S-Sulfat und durch mikrochemische Bestimmung des Gehaltes und der Zusammensetzung der Glykosaminglykane untersucht. Die wichtigsten Befunde waren: 1. Zwischen 1 und 4–8 Wochen veränderte sich nichtmetachromatisches Bindegewebe zu metachromatisch gefärbtem Knorpel, und der Anteil an Chondroitin-Sulfat nahm auf Kosten der Glykoproteine signifikant zu. 2. Bis zu 4 Wochen war der Hauptteil des defekten Gebietes mit neugebildetem Knochen gefüllt; nach dieser Zeit lag dieser Bezirk oberhalb der Verknöcherungsgrenze in Richtung der Gelenkoberfläche. 3. Nach 8 Wochen bestand die Gelenkoberfläche des defekten Gebietes in einem Drittel der Fälle aus hyalinem Knorpel, der morphologisch, autoradiographisch und chemisch dem Gelenkknorpel in Bezug auf die Verteilung von Glykosaminoglykanen glich. Hyaliner Knorpel wurde hauptsächlich an Stellen beobachtet, wo neugebildeter Knochen die Markhöhle geschlossen hatte. 3. Nach 8 Wochen bestand die Gelenkoberfläche des defekten Gebietes in einem Drittel der Fälle aus hyalinem Knorpel, der morphologisch, autoradiographisch und chemisch dem Gelenkknorpel in Bezug auf die Verteilung von Glykosaminoglykanen glich. Hyaliner Knorpel wurde hauptsächlich an Stellen beobachtet, wo neugebildeter Knochen die Markhöhle geschlossen hatte. 4. Nach 8 Wochen bestanden Teile der Gelenkoberfläche des Defektes in zwei Dritteln der Fälle nicht nur aus Knorpel, sondern auch aus fibrösem Gewebe, welches vor allem in den seitlichen Teilen des Defektes und an Stellen vorlag, wo die Markhöhle gegenüber der Gelenkoberfläche nicht mit Knochengewebe verschlossen worden war. Die Glykoproteinfraktion nahm im Vergleich zur Chondroitin-Sulfatfraktion zu. 5. Nach 20 Wochen zeigten sich in den meisten Fällen bei neugebildetem Knorpel degenerative Veränderungen, welche durch eine gewisse Abnahme des Chondroitin-Sulfats wiedergegeben wurden.
    Notes: Abstract A limited, standardized osteochondral defect was created in adult rabbits and the regenerated tissue was examined histologically and autoradiographically after labellingin vitro with35S-sulphate, and microchemically for its content and composition of glycosaminoglycans. The principal findings were: 1. Between 1 week and 4 to 8 weeks, non-metachromatic connective tissue differentiated to metachromatically stained cartilage, and the proportion of the chondroitin sulphate increased significantly at the expense of the glycoproteins. 2. Up to 4 weeks, the major part of the defect area was filled with newly formed bone; after this time, the area lay above the level of the “tidemark”, towards the articular surface. 3. Hyaline cartilage with morphological, autoradiographic and chemical resemblance to the articular cartilage in terms of the distribution of glycosaminoglycans constituted the articular surface of the defect area in one-third of the cases at observation times after 8 weeks. Hyaline cartilage was observed mainly in areas where newly formed bone had closed the medullary cavity. 4. In two-thirds of the cases, after 8 weeks, parts of the articular surface of the defect consisted not only of cartilage but also of fibrous tissue, occurring mainly in the lateral parts of the defect and in areas where the medullary cavity facing the articular surface had not been sealed by bone tissue. The glycoprotein fraction increased relative to the chondroitin sulphate fraction. 5. In most cases after 20 weeks, newly-formed cartilage underwent degenerative changes, which were reflected in some reduction of the chondroitin sulphate.
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  • 52
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    Calcified tissue international 8 (1971), S. 228-236 
    ISSN: 1432-0827
    Keywords: Skin ; Calcinosis ; Keratin ; Chemistry ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des études histologiques antérieures ont montré que le follicle pileux est particulièrement susceptible de se calcifier, lorsque la peau de rats hypercalcémiques est lésée. Des analyses chimiques et par diffraction aux rayons X du follicule ont confirmé ce résultat. — En se basant sur l'augmentation du calcium et du phosphore, les calcifications débutent dans le tissue folliculaire 6–12 h après une blessure d'intensité moyenne de la peau de rats, ayant reçu du dihydrotachysterol (DHT), et 24–48 h après une blessure similaire chez des rats non injectés. Les diagrammes de diffraction aux rayons X sont diffus. Trois heures après la blessure, on note une augmentation du calcium du tissu folliculaire qui ne semble pas en rapport avec le DHT qui traduit probablement une liaison de calcium plutôt qu'un dépot minéral.
    Abstract: Zusammenfassung Frühere histologische Untersuchungen haben gezeigt, daß der Haarfollikel besonders anfällig für Verkalkungen ist, wenn die Haut von hypercalcämischen Ratten verletzt wird. Dieses Resultat wurde nun durch direkte chemische Bestimmungen und Röntgendiffraktions-analysen von Follikelgewebe bestätigt. Aufgrund der erhöhten Calcium- und Phosphatwerte kann gesagt werden, daß nach einer leichten Quetschung der Haut von Ratten, die mit Dihydrotachysterol (DHT) behandelt wurden, im Haarfollikelgewebe nach 6–12 Std Mineral-ablagerungen stattfanden, wogegen Kontrollratten mit der gleichen leichten Hautverletzung diese Ablagerungen erst nach 24–48 Std zeigten. Röntgendiffraktionsanalysen ergaben ein diffuses Apatit-Muster. Innerhalb 3 Std nach der Verletzung wurde ein Anstieg des Calcium-gehaltes im Follikelgewebe beobachtet, der nicht im Zusammenhang mit der DHT-Behandlung stand, also nicht eine Mineralablagerung, sondern eher eine Bindung von Calcium widerspiegelte.
    Notes: Abstract Previous histological investigations have shown that the hair follicle is particularly susceptible to mineralization when the skin of hypercalcaemic rats is injured. Direct chemical and X-ray diffraction analyses of follicle tissue have now confirmed this finding. As judged by increases in both calcium and phosphorus, mineral deposits began to form in hair follicle tissue 6–12 h after a mild crush injury to the skin of rats dosed with dihydrotachysterol (DHT), and 24–48 h after a similar injury to the skin of non-dosed rats. X-ray diffraction gave a diffuse apatite pattern. Within 3 h of injury there was a rise in the calcium content of follicle tissue which was not related to DHT-dosing and which was probably a reflection of calcium binding rather than mineral deposition.
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  • 53
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    Calcified tissue international 8 (1971), S. 304-319 
    ISSN: 1432-0827
    Keywords: Chemistry ; Calcium ; Phosphate ; Solubility ; Computer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un programme d'ordinateur a été mis au point pour calculer les activités ioniques du calcium et l'orthophosphate dans un grand nombre de solutions. Dans le cas de solutions synthétiques, les calculs sont vérifiés en comparant les valeurs de pH, obtenues par ordinateur, avec celles observées expérimentalement. Des essais de ce type, avec des solutions possèdant des concentrations de calcium et d'orthophosphate trouvées dans les liquides biologiques et à des valeurs de pH variant de 3.00 à 10.00, indiquent que le programme est adapté pour des applications biologiques. Le programme n'est pas effectif pour des solutions, dans les lesquelles l'ion bromure est la source principale de la force ionique, sans doute, par manque d'équation étendue de Debye-Hückel dans ces circonstances. Aucune formation de complexe de phosphate de sodium n'a été notée à des concentrations biologiques normales.
    Abstract: Zusammenfassung Es wurde ein Computer-Programm ausgearbeitet, um die Ionenaktivitäten von Calcium und Orthophosphat in einer breiten Varietät von Lösungen zu berechnen. Die Berechnungen wurden bei synthetischen Lösungen durch Vergleiche zwischen den auf diese Weise errechneten pH-Werten und den experimentell gefundenen kontrolliert. Diese Art Kontrollen mit Calcium-und Orthophosphatkonzentrationen, wie sie in biologischen Flüssigkeiten gefunden werden, und mit pH-Werten zwischen 3,0 und 10,0 wies darauf hin, daß das Programm für biologische Anwendungen geeignet war. Das Programm konnte nicht benützt werden für solche Lösungen, bei welchen hauptsächlich das Bromidion zur Einstellung der Ionenstärke verwendet wurde, vermutlich weil die erweiterte Debye-Hückel-Gleichung unter diesen Umständen nicht anwendbar ist. Die Bildung eines Natriumphosphat-Komplexes unter normalen biologischen Konzentrationen konnte nicht nachgewiesen werden.
    Notes: Abstract A computer program has been designed to calculate the ionic activities of calcium and orthophosphate in a wide variety of solutions. In the case of synthetic solutions the calculations were checked by comparing the computed pH values with those observed experimentally. Tests of this type with solutions having the concentrations of calcium and orthophosphate found in biological fluids and with pH values ranging from pH 3.0–10.0 indicated that the program was suitable for biological applications. The program was not effective for solutions in which the bromide ion was a principal source of ionic strength probably because of the failure of the extended Debye-Hückel equation under those circumstances. No evidence for the formation of any sodium phosphate complex at normal biological concentrations could be found.
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  • 54
    ISSN: 1432-0827
    Keywords: Connective Tissue ; Vitamin D deficiency ; Hydroxyproline excretion ; Glycosaminoglycan excretion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The urinary excretion of two connective tissue metabolites was studied in both control and vitamin D deficient rats. Hydroxyproline (HyPRO) excretion was determined after 2, 13 and 22 months (experiment I). It decreased with aging in animals receiving the control diet. On the contrary, this excretion increased as a function of age in vitamin D deficient animals. At the age of 22 months, HyPRO excretion was respectively 31 and 1708 µg a day in control and deficient animals. HyPRO and glycosaminoglycans (GAG) excretion was measured on a group of both control and vitamin D deficient rats at the age of 21 months (experiment II). These results confirm the high excretion of HyPRO in deficient animals. On the contrary, the GAG excretion was higher in control animals than in deficient ones, the mean excretion being respectively 412 and 234 µg a day.
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  • 55
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    Calcified tissue international 10 (1972), S. 171-197 
    ISSN: 1432-0827
    Keywords: Amorphous ; Crystalline ; Calcium phosphate ; Chemistry ; Composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des échantillons non lavés de phosphate de calcium amorphe (ACP) contiennent une fraction labile, non remplaçable, riche en phosphate acide avec un rapport Ca/P faible: cette fraction est perdue de façon irréversible au cours du lavage. De l'ACP frais, précipité entre pH 6.6–10.6, varie dans un rapport molaire Ca/P de 1.18 à 1.50 et dans un rapport HPO 4 2− /P total de 33.0% à 10.1%. A pH 7.40, de l'ACP frais a un rapport molaire Ca/P de 1.36±0.02 et contient 22.8 (±2.2)% HPO 4 2− . Les résultats obtenus avec du précipité non lavé ne peuvent s'expliquer par du Ca2+ emprisonné et de l'HPO 4 2− ou du Na+, Cl− et CO 3 2− exogènes. Les phosphates de calcium amorphes constituent une classe de sels ayant des caractères chimiques variables et des propriétés physiques identiques, comparables au verre. Le CaHPO4·xH2O non cristallin peut être un ACP, surtout au cours des phases précoces de formation. A des pH physiologiques, l'ACP se transforme en petits cristaux applatis contenant de fortes quantités de phosphate acide facilement remplaçable. Le fait de laver la couche de surface produit un changement chimique dans les nouveaux cristaux: des cristaux non lavés donnent des diagrammes de diffraction d'apatite peu cristallins, ainsi que des spectres infra-rouges peu nets, intermédiaires entre des apatites et du phosphate octocalcique. Des explications structurales sont proposées et les compositions minérales amorphe/cristalline de l'os et du cartilage sont recalculées.
    Abstract: Zusammenfassung Ungewaschene Proben von amorphem Calciumphosphat (ACP) enthalten eine unersetzliche labile Fraktion, welche reich an saurem Phosphat ist und ein niederes Ca/P-Verhältnis hat und welche während des Waschprozesses unwiderruflich verloren geht. Natives ACP, welches im pH-Bereich 6,6–10,6 ausgefällt wurde, variierte im molaren Ca/P-Verhältnis zwischen 1,18 und 1,50 und in HPO 4 2− /totales P zwischen 33,0 und 10,1%. Bei pH 7,40 hatte natives ACP ein molares Ca/P-Verhältnis von 1,36±0,02 und enthielt 22,8 (±2,2)% HPO 4 2− . Die Werte beim ungewaschenen Niederschlag rühren weder von aus dem Überstand aufgenommenem Ca2+ und HPO2−, noch von außen kommendem Na+, Cl− und CO 3 2− her. Die amorphen Calciumphosphate werden als eine Klasse von Salzen erkannt, welche veränderliche chemische, aber identische glasartige physicochemische Eigenschaften haben. Nicht kristallines CaHPO4·xH2O kann auch ein ACP sein, besonders in den frühen Bildungsstadien. Bei physiologischem pH verwandelt sich ACP in kleine plattenförmige Kristalle, welche große Mengen von leicht ersetzbarem saurem Phosphat enthalten. Das Waschen dieser Oberflächenschicht erzeugte chemische Veränderungen in den resultierenden Kristallen; ungewaschene Kristalle zeigten ein Diffraktionsmuster, das nur schwach demjenigen des kristallinen Aspatites glich, aber ein schlecht aufgelöstes Infrarotspektrum, welches zwischen Apatit und Octocalciumphosphat war. Es werden strukturelle Erklärungen für alle diese Phenomena diskutiert, und revidierte amorph/kristalline Mineralzusammensetzungen von Knochen und Knorpel wurden neu berechnet.
    Notes: Abstract Unwashed samples of amorphous calcium phosphate (ACP) contain an irreplaceable labile fraction, rich in acid phosphate and low in Ca/P ratio, which is irreversibly lost during the washing process. Native ACP precipitated in the pH range 6.6–10.6 varied in Ca/P molar ratio from 1.18 to 1.50 and in HPO 4 2− /total P from 33.0% to 10.1%. At pH 7.40, native ACP had a Ca/P molar ratio of 1.36±0.02 and contained 22.8 (±2.2)% HPO 4 2− . Unwashed precipitate data could not be attributed to either trapped supernatant Ca2+ and HPO 4 2− or extraneous Na+, Cl−, and CO 3 2− . The amorphous calcium phosphates are recognized as a class of salts having variable chemical but identical glass-like, physicochemical properties. Non-crystalline CaHPO4·xH2O may also be an ACP, especially during early formative stages. At physiological pH, ACP transforms to small platy crystals containing large amounts of readily-replaceable acid phosphate. Washing this surface layer produced chemical alterations in the resultant crystals; unwashed crystals had poorly-crystalline apatitic diffraction patterns but exhibited poorly-resolved infrared spectra intermediate between apatite and octacalcium phosphate. Structural explanations for all these phenomena are discussed, and revised bone and cartilage amorphous/crystalline mineral compositions have been re-calculated.
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    Calcified tissue international 25 (1978), S. 75-83 
    ISSN: 1432-0827
    Keywords: Rat ; Fluorosis ; Enamel ; Scanning electron microscopy ; Low temperature incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Sixteen 58-day-old male rats of Wistar strain, with a mean body weight of 179 g, were divided into two equal groups. Each group of eight animals was maintained for 70 days on drinking water, ad lib., containing no fluorine (control group) and 100 ppm of fluorine (experimental group). All specimens examined were obtained from the incisal portions of the incisors. The following types of enamel specimens were prepared for scanning electron microscopy: (1) acid-etched specimens; (2) acid-etched specimens followed by low temperature microincineration; and (3) fractured specimens. The enamel formed during high fluoride exposure showed marked hypocalcification, that is, the crystallite density in the prism core and interprismatic region was lower than that of control animals. The organic substances appeared to increase in these regions. These changes were prominent in the outer and middle enamel layers. Such changes following fluoride administration appear to indicate an inhibition of enamel maturation, that is, an inhibition of the mineral deposition and/or an inhibition of organic matrix withdrawal.
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    Calcified tissue international 23 (1977), S. 39-44 
    ISSN: 1432-0827
    Keywords: Dental cementum ; Collagen ; Protein ; Chemistry
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    Notes: Summary Cyanogen bromide (CNBr) peptides were prepared of the insoluble collagen of bovine dental cementum. Following chromatographic separation, the peptides were identified by their amino-acid composition. Type I collagen ([α1(I)]2α2) accounted for more than 90% of the organic matrix, while Type III collagen ([α1(III)]3) was present at a level of approximately 5%. Amino-acid analyses revealed that the CNBr peptides from α1(I) and α2 chains of cementum closely resembled the corresponding peptides from calf skin. The only systematic difference was a higher level of hydroxylation of prolyl and lysyl residues of the cementum peptides.
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  • 58
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    Calcified tissue international 23 (1977), S. 87-94 
    ISSN: 1432-0827
    Keywords: Calcium ; Osteoporosis ; Lactation ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The calcium homeostatic mechanism was challenged in adult female rats by feeding them a calcium-deficient diet containing oxalate, and by subjecting them to pregnancy and lactation. The regimen caused a substantial weight loss, especially in those animals which reared their young well. Severe hypocalcaemia was observed in the lactating rats. Serum-P was slightly elevated. The content of hydroxyproline in serum was considerably elevated, reflecting the degree of calcium deprivation. Serum proteins were least influenced. The calcium depriving regimen reduced the growth of long bones, but did not stop it. The ash content of the bones was considerably reduced, the degree of reduction depended on the degree of calcium deprivation. Ash as percentage of total bone organ was reduced, but not to the same extent as total ash. Analyses of different parts of femur showed that the proximal and distal parts had lost more bone mineral than the diaphyseal shaft. The ash content of cortical bone tissue from the femur was estimated by a volumetric method. No differences were observed between test groups and controls, indicating that no measurable amounts of bone mineral had been removed from the walls of the vascular canals or by osteocytic osteolysis. Planimetric determinations on cross sections from femora disclosed that a great amount of bone had been removed from the endosteal surface of the diaphysis, while the periosteal surface demonstrated reduced bone apposition.
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  • 59
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    Calcified tissue international 32 (1980), S. 63-68 
    ISSN: 1432-0827
    Keywords: Rat ; Bone formation ; Fluorochrome ; Microphotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A method for quantitative studies of the formation rate of bone has been developed. After vital staining with calcein, the fluorescence of a bone section was measured with a microphotometer controlled by a mini computer. After staining the bone structure with alizarin red S in a second step, the section was measured in transmitted light. The two data sets were combined and the shortest distances between the bone surface and the fluorescence lines were computed. With this information the distance distribution and the bone area between the label and the surface could be calculated in two different ways: with the single labeling and the continuous labeling techniques. The advantages and disadvantages of the two methods are discussed and compared with those of other techniques.
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  • 60
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    Calcified tissue international 32 (1980), S. 113-122 
    ISSN: 1432-0827
    Keywords: Rat ; Bone ; Metaphysis ; Quantitative ; Aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purpose of this work was to analyze the proximal tibial metaphysis of the 170 g rat in a quantitative histologic fashion which would allow some relation to tissue age to be established. Stained 3 µm thick tissue sections were analyzed with the aid of a Merz grid on an eyepiece reticule and a light microscope. Tissue mass and cell distribution were studied in all areas. The rate of change in tissue mass during aging of the metaphysis was calculated. Two regions of the metaphysis were identified. One, corresponding to the primary spongiosa, less than 4.45 days of age, is a region of high turnover of hard tissue and high numbers of osteoblasts and osteoprogenitor cells. The other, corresponding to the secondary spongiosa, is a region of relatively low net tissue turnover and low numbers of osteoblasts and osteoprogenitor cells. Osteoclasts were found relatively more uniformly distributed through the metaphysis than were osteoblasts and osteoprogenitor cells. The rate of bone formation in the primary spongiosa is 50 times that found in the Haversian bone of the rib of 5-year-old humans and about 500 times that found at the cortical-endosteal surface of ribs of 5-year-old humans. It is argued that both cell distribution and tissue distribution in the metaphysis support the concept that osteoblasts and osteoclasts, rather than osteocytes, are responsible for the maturation of the metaphysis. The inhomogeneous distribution of both cells and tissue in the metaphysis has definite meaning for the interpretation of findings concerning the incorporation of radionuclides into the skeleton.
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  • 61
    ISSN: 1432-0827
    Keywords: Rat ; Hypophysectomy ; Dietary phosphorus deprivation
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    Notes: Summary The demands of growth are known to exacerbate the effect of phosphorus deprivation (PD). We examined whether changes associated with PD could be prevented in young rats in which growth and growth hormone (GH) were eliminated by hypophysectomy (HPX) and whether PD in normal intact rats (INT) was associated with increased secretion of GH. INT or thyroxine- and ACTH-replaced HPX rats were fed one of the three diets: 0.31% P (NP); 0.027% P (LP), and 0.31% P, pair-fed with LP-mates (NP-PF). The results indicate that HPX did not qualitatively alter several physiologic responses to PD: (a) serum and urinary phosphorus (P) decreased and urinary calcium (Ca) increased; (b) net intestinal Ca retention fell and duodenal sac uptake of45Ca rose; and (c) external P balance was restored and duodenal sac uptake of32P-phosphate increased. Only the hypercalcemia seen in INT, LP rats was prevented by HPX. In INT rats serum immunoassayable GH levels, measured in single samples, were not different between different dietary groups while pituitary bioassayable GH was reduced in both LP and NP-PF rats when compared to the NP rats. Thus, except for hypercalcemia, the physiologic responses associated with PD are not prevented by the elimination of growth and GH, and the development of these responses in INT rats was not associated with a consistent or specific alteration in GH secretion.
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  • 62
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    Keywords: Cortisol ; Cortical bone ; Bone biomechanics ; Rat ; Femur
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    Notes: Summary Doses of 8, 16 (low), 32, 48, 64 (medium), and 150 (high) mg/kg/day of cortisol were administered to groups of 8 growing rats each during 16 days, and their femurs were then submitted to 3-point bending tests at low strain rate. Low doses had no effect. Medium doses, previously shown to improve calcium (Ca) balance and weight gain in the species, augmented diaphyseal elastic and ultimate strength, stiffness, and plastic-to-elastic deformation ratio with respect to untreated controls. This effect was achieved either by enhancing bone mass (volume, sectional moment of inertia, wall/lumen ratio) without changes in material quality parameters (32 mg/kg/day) or, conversely, by increasing bone tissue mechanical properties (stress, modulus of elasticity) not affecting bone geometry (48 and 64 mg/kg/day). The highest dose, known to depress Ca balance and weight gain, impaired diaphyseal mechanical performance in controls by substantially reducing bone mass without major variation in bone material properties, that is, developing a true osteopenic state in mechanical terms. The energy elastically absorbed per unit volume (proportional to the risk of comminute fractures) was greater with the highest dose because of enhanced deformability and diminished bone mass. The biphasic dose-response curves obtained, grossly parallel to those previously demonstrated for metabolic actions of cortisol in the same species, showed that biomechanical repercussion of this treatment on bone depends on different, dose-dependent effects which vary independently in temporal course, intensity, and sign.
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  • 63
    ISSN: 1432-0827
    Keywords: Loading ; Strain ; Modeling ; Rat ; Ulna
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    Notes: Abstract Adaptive changes in bone modeling in response to noninvasive, cyclic axial loading of the rat ulna were compared with those using 4-point bending of the tibia. Twenty cycles daily of 4-point bending for 10 days were applied to rat tibiae through loading points 23 and 11 mm apart. Control bones received nonbending loads through loading points 11 mm apart. As woven bone was produced in both situations, any strain-related response was confounded by the response to direct periosteal pressure. Four-point bending is not, therefore, an ideal mode of loading for the investigation of strain-related adaptive modeling. The ulna's adaptive response to daily axial loading over 9 days was investigated in 30 rats. Groups 1–3 were loaded for 1200 cycles: Group 1 at 10 Hz and 20 N, Group 2 at 10 Hz and 15 N, and Group 3 at 20 Hz and 15 N. Groups 4 and 5 received 12,000 cycles of 20 N and 15 N at 10 Hz. Groups 1 and 4 showed a similar amount of new bone formation. Group 4 showed the same pattern of response but in reduced amount. The responses in Groups 2 and 3 were either small or absent. Strains were measured with single-element, miniature strain gauges bonded around the circumference of dissected bones. The 20 N loading induced peak strains of 3500–4500 μstrain. The width of the periosteal new bone response was proportional to the longitudinal strain at each point around the bone's circumference. It appears that when a bone is loaded in a normal strain distribution, an osteogenic response occurs when peak physiological strains are exceeded. In this situation the amount of new bone formed at each location is proportional to the local surface strain. Cycle numbers between 1200 and 12,000, and cycle frequencies between 10 and 20 Hz have no effect on the bone's adaptive response.
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    Calcified tissue international 55 (1994), S. 33-37 
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Rat ; Orchidectomy ; Exercise ; Strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The effect of exercise on castration-induced osteoporosis in 3-month-old male rats weighing 264±4 g at the beginning of the experiment was studied. A testosterone deficiency was induced by orchidectomy (ORC), and the exercise group ran 10 m/minute for 1 hour a day on a treadmill at 0% grade. There were seven groups of eight rats (n=56) randomized into a control group killed at time 0, and sham, ORC and ORC and exercise groups killed at 4 and 8 weeks. ORC reduced body weight gain (with analysis of variance (ANOVA) P〈0.001), and at 4 weeks the body weight was 343±14 g in ORC group and 301±4 g in the ORC and exercise group (P〈0.01). The increase in femoral length was slower in the ORC+exercise groups. The ash weight of the tibia did not decrease significantly after ORC or ORC+ exercise. ORC did not affect 45Ca incorporation, but exercise slightly increased it in the whole tibia 8 weeks after ORC (with ANOVA P=0.057). ORC had significantly lowered the trabecular bone volume in the secondary spongiosa of the distal femur at 4 and 8 weeks, and exercise did not prevent this. This is an opposite finding to our previous study with ovariectomized female rats [12]. ORC also significantly had reduced the osteoblast-lined trabecular bone surface and the number of osteoclasts by 8 weeks after the operation. Exercise increased the osteoblast-lined surface and the number of osteoclasts. The mechanical strength of the femoral neck also was reduced after ORC and this was not prevented by exercise either. In conclusion, ORC reduces bone growth and turnover which leads to osteopenia in growing rats. Moderate treadmill exercise does not reverse the ORC-induced loss of trabecular bone and the reduced mechanical strength of the femoral neck, although it has a positive effect on the osteoblast and osteoclast indices and on calcium incorporation into bone.
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    Calcified tissue international 56 (1995), S. 42-48 
    ISSN: 1432-0827
    Keywords: Phenytoin ; Bone formation ; Osteocalcin ; Alkaline phosphatase ; Osteogenesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Long-term use of phenytoin for the treatment of epilepsy has been associated with increased thickness of craniofacial bones. The aim of the present study was to evaluate the possibility that low doses of phenytoin are osteogenic in vivo by measuring the effects of phenytoin administration on serum and bone histomorphometric parameters of bone formation in two rat experiments. In the first experiment, four groups of adult male Sprague-Dawley rats received daily I.P. injections of 0, 5, 50, or 150 mg/kg/day of phenytoin, respectively, for 47 days. Serum alkaline phosphatase (ALP) and osteocalcin were increased by 5 and 50 mg/kg/day phenytoin. The increases in osteocalcin and ALP occurred by day 7 and day 21, respectively. The tibial diaphyseal mineral apposition rate (MAR) at sacrifice (day 48) was significantly increased in rats receiving 5 mg/kg/day phenytoin. At a dose of 150 mg/kg/day, the increase in serum ALP, osteocalcin and MAR was reversed. No significant differences in serum calcium, phosphorus, or 1,25(OH)2D3 levels were seen. In a second experiment, three groups of rats received daily I.P. injection of lower doses of phenytoin (i.e., 0, 1, or 5 mg/kg/day, respectively) for 42 days. Phenytoin also did not affect the growth rate or serum calcium, phosphorus, and 25(OH)D3 levels. Daily injection of 5 mg/kg/day phenytoin significantly increased several measures of bone formation, i.e., serum ALP and osteocalcin, bone ALP, periosteal MAR, and trabecular bone volume. However, rats receiving lower doses of phenytoin (i.e., 1 mg/kg/day) did not show significant increases in the serum bone formation parameters. In contrast, metaphyseal osteoblast surface, osteoblast number, osteoid thickness, surface, and volume were all significantly increased in rats treated in 1 mg/kg/day but not with 5 mg/kg/day phenytoin, suggesting that the tibial diaphysis and metaphysis bone formation parameters might have different dose-dependent responses to phenytoin treatment. Administration of the test doses of phenytoin did not significantly affect the histomorphometric bone resorption parameters. In conclusion, these findings represent the first in vivo evidence that phenytoin at low doses (i.e., between 1 and 5 mg/kg/day) is an osteogenic agent in the rat.
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    Calcified tissue international 8 (1971), S. 197-210 
    ISSN: 1432-0827
    Keywords: Fluorescence ; Calcium ; Collagen ; Chemistry ; Bone ; Dentine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des composants fluorescents de l'os et la dentine sont séparés des hydrolysats alcalins de leur marice sur des colonnes Sephadex C25 CM d'échange cationique. Les concentrations en fluorescence et le spectre d'excitation (λ max 330 nm) et d'émission (λ max 395 nm) sont les mêmes que ceux observés au niveau des matrices intactes et gélatinisées. Les paramètres de fluorescence ne sont pas altérés par hydrolyse. La filtration sur gel à l'aide de colonnes Sephadex G 10 perment de différencier le matériel isolé en deux composants, ayant la même fluorescence et la même absorption UV. La fluorescence est indépendante de pH de 3.5–9.5. Des études de dialyse et de filtration sur gel de matrices gélatinisées indiquent une association étroite du matériel fluorescent avec les chaines polypeptidiques de collagène.
    Abstract: Zusammenfassung Fluorescierende Bestandteile aus Knochen und Dentin wurden in Sephadex C25 CM Kationen-Austauschersäulen von alkalischen Hydrolysaten ihrer Matrices getrennt. Die Fluorescenzintensitäten sowie die Erregungs- (λ max 330 nm) und Emissions- (λ max 395 nm) Spektren waren dieselben wie bei intakten und gelatinisierten Matrices. Die Fluorescenzparameter wurden durch die Hydrolyse nicht verändert. Eine Gelfiltration über Sephadex-G10-Säulen trennte das isolierte Material in 2 Komponenten auf, welche gleiche Fluorescenz- und UV-Absorptionseigenschaften zeigten. Im pH-Bereich zwischen 3,5 und 9,5 war die Fluorescenz unabhängig vom pH. Dialysierversuche sowie Gelfiltrationsexperimente mitden gelatinisierten Matrices zeigten eine starkgefügte Bindung des fluorescierenden Materials mit den Polypeptidketten des Kollagens.
    Notes: Abstract Fluorescent components in bone and dentine were separated from alkaline hydrolysates of their matrices on Sephadex C25 CM cationic exchange columns. The fluorescence levels, and the excitation (λ max 330 nm) and emission (λ max 395 nm) spectra, were the same as those observed in the intact and gelatinised matrices. The fluorescence parameters were unaltered by the hydrolysis procedure. Gel filtration on Sephadex G. 10 columns further resolved the isolated material into two components with the same fluorescence and UV absorption properties. The fluorescence was independent of pH over the range 3.5–9.5. Dialysis and gel filtration studies on the gelatinised matrices indicated a firmly-bonded association of the fluorescent material with the collagen polypeptide chains.
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    Calcified tissue international 33 (1981), S. 223-231 
    ISSN: 1432-0827
    Keywords: Protein deficiency ; Bone formation ; Skeletal development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Protein deficiency was produced by freely feeding young rats a 1% lactalbumin diet for 12 weeks in order to study the effects of protein-calorie malnutrition on skeletal development. During the experiment the food and caloric intake and weight of the experimental animals decreased, while those parameters of the control animals progressively increased. However, when gross caloric intake was expressed as a function of the metabolic size of the animal, the caloric consumption was similar for both groups of animals. The protein-deficient animals exhibited micro-radiographic and histological features of an abnormal pattern of endochondral bone formation. Appositional bone growth, as determined by the daily appositional rate and the percentage of endosteal surfaces undergoing active bone formation, was significantly decreased in these animals, as was the percentage of periosteal surfaces exhibiting resorption. Both chemical analyses of the whole bone and electron probe microanalysis in the specific area of actively calcifying bone revealed no significant differences between the mineral content of control and protein-deficient animals. This study distinguishes the effects of protein deficiency from that of combined protein-calorie deprivation and demonstrates that the abnormal skeletal development observed was the result of a decrease in the quantity of bone formed rather than an altered mineral content.
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  • 68
    ISSN: 1432-0827
    Keywords: Rat ; Incisor ; Amelogenesis ; Acid phosphatase ; Ferritin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Acid phosphatase was localized in rat incisor ameloblasts without prior decalcification. Whenβ-glycerophosphate was used as the substrate, an intense reaction was observed in the supranuclear region of the secretory ameloblasts. But the reaction was dramatically reduced at the transitional stage and was very weak in the maturation ameloblasts. Whenp-nitrophenylphosphate was the substrate, the reaction product was consistently seen in the Golgi cisternae and the vesicular components of the ameloblasts at all stages of enamel development. These observations suggest that there are two acid phosphatases in ameloblasts. One is in the secretory ameloblasts and the other in the transition and maturation ameloblasts. X-ray micro-analyses for Fe and Pb showed that Fe and acid phosphatase were in the ferritin-containing vesicles at the later stage of enamel maturation. This evidence suggests that ferritin is digested in these vesicles for the release of the Fe pigment to the enamel. An increase in the number of intercellular bridges between ameloblasts was correlated with the dramatic decrease in height of ameloblasts at the pigment release stage. The ameloblast membranes were acid phosphatase positive at the intercellular bridges whenp-nitrophenylphosphate was the substrate. This activity may be involved in the reduction in the surface area of the ameloblast membranes.
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    Calcified tissue international 12 (1973), S. 125-136 
    ISSN: 1432-0827
    Keywords: Mineralization ; Molt ; Isopod ; Chemistry ; Light microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Au cours de la phase inhabituelle de mue d'un isopode d'eau courante,Lirceuts brachyrus, la moitié postérieure de l'exosquelette est éliminée 24 heures avant la moitié antérieure. A ce stade, une reminéralisation se développe dans la partie postérieure alors que la partie antérieure est dans un stade de pré-mue. Le pourcentage de différence en calcium dans les deux moitiés à mi-mue et mue complète est respectivement de 22% (p〈0.01) et 33% (p〈0.01), indiquant une complexation du calcium pendant la mue. La rapidité de la reminéralisation est illustrée par le fait que le contenu minéral total double dans la partie postérieure entre la mi-mue et la mue totale et dans la partie antérieure entre la fin de la mue et un jour après. Le carbonate de calcium, sous forme de calcite, a pu être identifié par diffraction électronique de coupes fines des téguments.
    Abstract: Zusammenfassung Während der ungewöhnlichen Häutungssequenz des Frischwasser-IsopodenLirceus brachyurus (Harger) wird die hintere Hälfte des äußeren Skeletts 24 Std vor der vorderen Hälfte abgestoßen. In der halbgehäuteten Phase erfolgt Remineralisation im hinteren Teil, während der vordere Teil in einem Vorhäutungszustand ist. Der prozentuale Unterschied des Calciums in den zwei Hälften bei Halb- und Vollhäutungszustand ist 22% (p〈0,01) bzw. 33% (p〈0,01), was andeutet, daß Calcium während der Häutung abgesondert wird. Die Geschwindigkeit der Remineralisation erhellt aus der Tatsache, daß sich der Gesamtmineralgehalt im hinteren Teil zwischen Halt- und Vollhäutung, in der vorderen Hälfte jedoch zwischen Endhäutung und einem Tag nach der Häutung verdoppelt. Calciumcarbonat in kristalliner Calcitform wurde mittels Elektronendiffraktion von dünnen Hautschnitten nachgewiesen.
    Notes: Abstract During the unusual molt sequence of the fresh-water isopod,Lirceus brachyrus (Harger), the posterior half of the exoskeleton is shed 24 hours before the anterior half. At the half-molt stage, occurs in the posterior part while the anterior portion is in a pre-molt condition. The percentage difference in calcium in the two halves at half-molt and full-molt is22 (p〈0.01) and33 (p〈0.01) respectively, an indication that calcium is sequestered during The rapidity of remineralization is illustrated by the fact that the total mineral content doubles in the posterior part between half and full molt and in the anterior half between the end of molt and one day after ecdysis. Calcium carbonate in the calcite cystalline form was demonstrated by electron diffraction of thin sections of the integument.
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    Calcified tissue international 13 (1973), S. 259-270 
    ISSN: 1432-0827
    Keywords: Fluorapatite ; Exchange ; Chemistry ; Crystallography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Un échantillon minéral provenant de Burgess, Canada s'est révélé être un speciment exceptionnellement pur de fluoroapatite après analyse chimique et cristallographique. La composition globale de cet échantillon est la suivante: $$(Ca^2 )9.98(Sr^{2 + } ,Na^ + ,K^ + ,Mg^{2 + } )0.02(PO_4^{3 - } )5.98(HCO_3^ - ,CO_3^{2 - } )0.02(F^ - )2$$ . L'axe cristallographique C est de 6.865 A et l'axe a de 9.374 A. Des expériences d'échanges réalisés à l'aide de45Ca,32P et18F indiquent la présence de gros cristallites de surface spécifique de l'ordre de 1 m2/g. Il apparait que l'interprétation physique des processus d'échange ne nécessite pas l'existence de compartiments séparés, avec chacun son propre facteur cinétique, les échanges semblent être simplement liés à un changement exponentiel dans l'énergie libre de la réaction. Pour la réaction suivante: $$(Ca)_5 (PO_4 )_3 OH solide + (F^ - ) \rightleftarrows (Ca)_5 (PO_4 )_3 F solide + (OH^ - )$$ , la constante thermodynamique de 101.26 a été calculée, suggérant que le fluorapatite se forme toujours aux dépens de l'hydroxyapatite dans des conditions physiologiques. Cette transformation se continue en abaissant le pH.
    Abstract: Zusammenfassung Eine Mineralprobe aus Burgess, Kanada, erwies sich nach chemischer und kristallographischer Analyse als außergewöhnlich reines Fluorapatit. Die Gesamtzusammensetzung entspricht: $$(Ca^{2 + } )_{9,98} (Sr^{2 + } ,Na^ + ,K^ + ,Mg^{2 + } )_{0,02} (PO_4^{3 - } )_{5,98} (HCO_3^ - ,CO_3^{2 - } )_{0,02} (F^ - )_2 $$ . Die kristallographische c-Achse wurde bestimmt und ergab 6,865 Å, und die a-Achse ergab 9,374 Å. Austauschwerte, welche durch Anwendung von45Ca,32P und18F erhalten wurden, deuteten auf große Kristalliten mit einer spezifischen Oberfläche von ca. 1 m2/g. Die Befunde deuten darauf hin, daß für die physikalische Erklärung des Austauschvorganges keine separaten Kompartimente mit eigenen kinetischen Faktoren nötig sind, sondern daß der Austausch mit dem exponentiellen Wechsel in der freien Energie der Reaktion in einfacher Beziehung steht. Für die Reaktion $$(Ca)_5 (PO_4 )_3 OH_{in fester Form} + (F^ - ) \rightleftarrows (Ca)_5 (PO_4 )_3 F_{in fester Form} + (OH^ - )$$ wurde als thermodynamische Konstante 101,26 errechnet, was darauf deutet, daß unter physiologischen Bedingungen immer Fluorapatit auf Kosten von Hydroxyapatit entsteht. Diese Umwandlung wird erhöht, wenn das pH erniedrigt wird.
    Notes: Abstract A mineral specimen from Burgess, Canada, proved upon chemical and crystallographic analyses to be an exceptionally pure sample of fluorapatite. The over-all composition corresponds to $$(Ca^{2 + } )_{9.98} (Sr^{2 + } ,Na^ + ,K^ + ,Mg^{2 + } )_{0.02} (PO_4^{3 - } )_{5.98} (HCO_3^ - ,CO_3^{2 - } )_{0.02} (F^ - )_2 $$ . The crystallographic c-axis was determined to be 6.865 Å, and the a-axis 9.374 A. Exchange data obtained by employing45Ca,32P, and18F indicate the presence of large crystallites with a specific surface of the order of 1 m2/g. It is indicated that the physical interpretation of the exchange process does not require the existence of separate departments, each with its own kinetic factor, but that the exchange may be simply related to the exponential change in the free energy of the reaction. For the reaction $$(Ca)_5 (PO_4 )_3 OH_{solid} + (F^ - ) \rightleftarrows (Ca)_5 (PO_4 )_3 F_{solid} + (OH^ - )$$ the thermodynamic constant has been calculated to be 101.26, implying that fluorapatite always will form at the expense of hydroxyapatite under physiologic conditions. This transformation will be furthered by lowering the pH.
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    Calcified tissue international 22 (1977), S. 77-84 
    ISSN: 1432-0827
    Keywords: Fluoride ; Blood plasma ; Enamel mineralization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract It is postulated that tissue fluid F concentrations are the primary determinants of fluoride effects on bones and developing teeth and that these concentrations are dependent on, or mirrored by, blood plasma F. It has earlier been shown that the plasma F levels are dependent on the dietary F supply as well as on skeletal F concentration. Fasting and post-ingestion or postinjection plasma F levels have been determined in rats on F doses that cause different degrees of enamel fluorosis. The results indicate that temporary peak values rather than elevated fasting values are responsible for the occurrence of enamel fluorosis and that the peak values must approach about 10 μM in order to block enamel formation by the ameloblasts. The diagnostic and prognostic importance of plasma F determinations is discussed.
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  • 72
    ISSN: 1432-0827
    Keywords: Bacterial amphophile ; Purification ; Chemistry ; Resorption ; Ca influx ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The bone resorptive factor and amphipathic antigen (AcA) previously identified by us in preparations fromActinomyces viscosus have been partially purified, characterized chemically, and compared. They elute at the same location on chromatography with Ac 22. The fatty acid composition of AcA and the bone resorptive factor is the same. Some differences in carbohydrate composition are observed. TheActinomyces factor does not affect calcium influx or cyclic AMP in isolated bone cells. Therefore it is concluded that AcA stimulates resorption either by gaining entrance into bone cells or by way of a yet undetermined second messenger.
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  • 73
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    Calcified tissue international 34 (1982), S. 376-381 
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; Bone ; Actin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Preliminary indications of the occurrence of actin and myosin in crude matrix vesicle preparations have been reported previously. In the present study extracellular matrix vesicles from rat alveolar bone were isolated. They were further purified by a sucrose density gradient. SDS-polyacrylamide gel electrophoresis of the purified vesicles revealed the presence of a polypeptide with a molecular weight of 43 K daltons and with electrophoretic mobility identical to that of blood platelet actin. The limited proteolysis of both 43 K dalton vesicular polypeptide and actin byStaphylococcus aureus-V8-protease revealed three fragments with identical electrophoretic mobility. In addition, the vesicular preparations inhibited the activity of DNase I, a property typical of actin monomers. Filamentous material extracted from matrix vesicles showed ultrastructural features of F-actin. Reaction of this material with heavy meromyosin resulted in arrowhead formation, which is characteristic of acto-heavy meromyosin. The occurrence of actin in extracellular matrix vesicles may account for their budding from the osteoblastic plasma membrane, their possible motility in the matrix, and maintenance of the spherical shape.
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  • 74
    ISSN: 1432-0827
    Keywords: Bone alkaline phosphatase ; Rat ; Vitamin D ; Sorbitol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In the femoral extremities of the adult rat containing the metaphysis, the epiphyseal cartilage, and the epiphysis, four alkaline phosphatase (AP) forms were distinguished on polyacrylamide gel electrophoresis. Two soluble forms were present in the 160,000 g supernatant: one of Mr 165 kDa and another of Mr 110–115 kDa, which exhibited a strong catalytical activity. Moreover, from the pellet, three membrane-bound forms of Mr 130, 110–115, and 100 kDa could be extacted with sodium deoxycholate. When denaturated AP was visualized by postelectrophoretic autoradiography of the phosphorylated intermediates, subunits always appeared as three monomers of Mr 75–80, 60–70, and 50–60 kDa. As four native forms but only three types of subunits were found to be present in the femur, it seems that, apart from homodimers, some heterodimers could also occur. Three types of diets were administered to three groups of rats for 5 weeks. Two are known to disturb bone mineralization: (1) a vitamin D3-deficient diet, and (2) the same as (1) but enriched with 12% sorbitol. The third was a normal diet containing vitamin D3. Concerning the effects on AP of dietary sorbitol and the vitamin D3-deficient diet, it was found that rats receiving the diet supplemented with sorbitol showed a substantial rise in the activity of the Mr 165 kDa form with the concomitant appearance of a new monomer of Mr 100 kDa. In contrast, rats fed the vitamin D3-deficient diet always displayed an increase in enzyme activity, principally of the Mr 100 and 110 kDa forms. In conclusion, the femur extracts of normal rats contained different forms of AP: either soluble 110–115 and 165 kDa forms or membrane-bound 130, 110–115, and 100 kDa forms. The administration of sorbitol-enriched diet induced a marked increase of the 165 kDa form whereas the administration of vitamin D3-deficient diet increased the 100 and 110 kDa forms.
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  • 75
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    Calcified tissue international 35 (1983), S. 107-110 
    ISSN: 1432-0827
    Keywords: Calcium ; Glucocorticoid ; Vitamin D ; Osteoporosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Eighty-eight adult male Sprague-Dawley rats were given a diet with either (a) 0.5% Ca and 0.6% P or (b) 0.01% Ca and 0.6% P. Osteopenia was created by adding prednisolone to the diet. The prophylactic effect of oral 1,25(OH)2D3 on the osteopenia was studied. It was found that prednisolone osteopenia in the rat was associated with defective Ca absorption. By giving an oral dose of 1,25(OH)2D3, it was possible to maintain normal Ca absorption during prednisolone treatment and to prevent the bone loss. No significant hypercalcemia or any kidney calcifications were seen. These results are in contrast to earlier findings, in which subcutaneous administration of 1,25(OH)2D3 failed to prevent prednisolone osteopenia because of its tendency to increase bone resorption.
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  • 76
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    Calcified tissue international 51 (1992), S. 30-34 
    ISSN: 1432-0827
    Keywords: PTHRP ; Anabolic ; Rat ; Bone ; Potency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Parathyroid hormone-related protein (PTHRP) has recently been purified from human tumors associated with the syndrome of humoral hypercalcemia of malignancy. The gene encoding PTHRP has been cloned, and based on predicted amino acid sequence, polypeptides comprising the first 36 [36Tyr(1–36) PTHRP amide] and 74 [(1–74)PTHRP] amino acids have been synthesized. Human (h) PTHRP (1–36) and (1–74) are potent bone-resorbing agents, and are catabolic for bone in vivo when given continuously at high doses. Bovine parathyroid hormone (bPTH) (1–34) is also catabolic for bone at high dose levels, but when given in low doses for weeks to months, it is anabolic. Although PTHRP possess several PTH-like properties in bone, hPTHRP (1–34) is reported to be only weakly anabolic in vivo. As polypeptide length influences PTHRP action, we evaluated hPTHRP(1–74) as an anabolic agent for bone in vivo. Twenty-four 4-week-old male Sprague-Dawley rats were given daily subcutaneous injections of hPTHRP(1–74) (1 and 2 nmol/100 g body weight, bw), bPTH(1–34) (4 nmol/100 g bw) or vehicle. Rats were sacrificed on day 12, and serum calcium, phosphorus, and 1,25 dihydroxyvitamin D and femoral bone dry weight, calcium content, and hydroxyproline content were measured. Serum calcium and phosphorus were equivalent in all groups. A significant increase in dry bone weight was observed in both PTHRP-treated groups compared with controls. PTHRP also caused a significant, dose-dependent increase in bone calcium and hydroxypro-line content. Results of these studies indicate that PTHRP (1–74) is anabolic for bone in vivo when administered at low-dosage levels for a prolonged period.
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  • 77
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    Calcified tissue international 54 (1994), S. 150-154 
    ISSN: 1432-0827
    Keywords: Vitamin D analog ; KH1060 ; Kidney transplantation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract KH1060 is a new 20-epi-vitamin D3 analog, which has exerted a considerable immunosuppressive potency in vitro. We have tested in vivo the effect of KH1060 on the suppression of renal allograft rejection in the rat. Allogenic kidney transplantation from DA donor rats to Lewis recipient rats treated intraperitoneally with KH1060 in doses from 0.2 to 6 μg/kg/day, or saline (placebo group), or CyA 10 mg/kg/day for 10 days (positive control group), was performed. Median graft survival time in KH1060-treated groups was 7–9 days, in the placebo group 6 days, whereas CyA led to long-term graft survival, 34 days in 50% of rats and 〉100 days in 50% of rats. In vivo, KH1060 failed to prolong renal allograft survival considerably, and led to development of hypercalcemia. Our results stress the existence of a large discrepancy between the in vitro and in vivo immunoregulatory effects of this vitamin D analog.
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  • 78
    ISSN: 1432-0827
    Keywords: Bone mechanics ; Bone composition ; Vitamin D3 ; Corticosteroid ; Rat
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    Topics: Biology , Medicine , Physics
    Notes: Abstract The effects of 1α-vitamin D3 were studied for 6 months in 2-month-old male and female rats on a moderately low calcium diet with or without low-dose prednisolone treatment. Both cortical bone mechanical and biochemical properties were examined. Femoral bone specimens were subjected to torsional loading tests. With age, bone strength and stiffness increased in both sexes, accompanied by an increased degree of mineralization (bone ash and calcium concentrations). During growth, strength and stiffness increased more in male than in female rats. When 1α-vitamin D3 (0.5 μg/kg/day) was given alone, bone mechanical competence improved significantly whereas insulin-like growth factor-I (IGF-I) and calcium concentrations in the bone matrix were significantly reduced. Treatment with low-dose prednisolone (0.5 mg/kg/day) alone did not influence bone mechanical properties compared with intact control rats (without prednisolone) although a significant reduction in calcium concentration and an increased phosphorus concentration were measured. A combined therapy with prednisolone and 1α-vitamin D3 significantly increased bone strength, toughness, and stiffness compared with control bones. Both mineralization degree (ash and calcium concentration) and IGF-I concentration were decreased. We conclude that (1) mechanical properties of rat cortical bones improve relatively more in males compared with agematched females during growth which is related to increased bone mass and size, (2) low-dose prednisolone treatment does not change mechanical properties in males, and altered them only nonsignificantly in females despite a change in mineralization degree in both sexes; (3) treatment with 1α-vitamin D3 results in a consistent increase in mechanical competence of the bone accompanied by a significant decrease in IGF-I concentration in the bone matrix.
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  • 79
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    Calcified tissue international 56 (1995), S. 83-87 
    ISSN: 1432-0827
    Keywords: Immunoradiometric assay ; Parathyroid hormone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Measurement of parathyroid hormone (PTH) in the rat is most often performed with competitive ligand radioimmunoassays (RIA) utilizing heterologous antibodies. We report here the validation of a newly developed homologous immunoradiometric assay (IRMA) for rat PTH. Two different goat antibodies to the amino-terminal sequence of rat PTH are utilized; one is immobilized onto plastic beads to capture the PTH molecules and the other is radiolabeled for detection. To test this new IRMA, 30 Sprague-Dawley rats were randomized into three treatment groups to receive by intraperitoneal injection: (1) saline 1 ml/kg (control); (2) calcium chloride 40 mg/kg (hypercalcemic); and (3) EDTA 300 mg/kg (hypocalcemic). Blood samples were taken at 0, 30, 60, 180, and 300 minutes after administration of the assigned treatment for measurement of ionized calcium (Ca2+) and serum PTH. Most of the variance in PTH levels was found to be due to changes in Ca2+ (r2=0.780, P〈0.0001). There was also a close temporal relationship between the two, with the highest levels of PTH occurring at the same measured time points as the lowest Ca2+, and vice versa. The measured detection limit of the IRMA was 3 pg/ml with intra-and interassay coefficients of variation of 1.74% and 3.07%, respectively. Serial dilutions with pooled rat serum, synthetic rat PTH-(1–34), and synthetic human PTH-(1–34) showed good parallelism with increased specificity for the pooled and synthetic PTH, despite a degree of crossreactivity with hPTH. The assay is able to quantitate rapid changes in PTH, providing all the advantages of IRMA methodology including technical simplicity and speed of performance, and is likely to become a useful tool in investigations of bone, mineral, and renal homeostasis using the rat.
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  • 80
    ISSN: 1432-0827
    Keywords: Fluoride ; Bone ; Defluoridation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The aim of this work was to explore the reduction of fluoride concentrations in the skeleton after stopping experimental fluoride administration. Fluoride was administered to the rats at varying doses (0, 50, 100 ppm in drinking water) and for different lengths of time (4, 13, 25 weeks). A series of fluoride concentrations across the full thickness of humerus, parietal bone, and vertebra arch in rats were measured by means of an abrasive micro-sampling technique. The distribution profiles of fluoride from periosteal to endosteal surfaces, which were apparently related to the histological structure of these bones, were U shaped in the humerus, V shaped in the parietal bone, and W shaped in the vertebra arch. The average fluoride concentrations in the bones increased significantly with each increasing dose and length of fluoride administration. The relative increments were similar between the different regions or the different bones. After stopping fluoride administration, on the other hand, the relative reduction of the average fluoride concentrations in the bones were 30–100%. They were greatly related to the length after stopping fluoride administration and the dose and length of fluoride administration, but also dependent upon the type of bone and the region examined.
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  • 81
    ISSN: 1432-1211
    Keywords: Key words Vβ13 ; CD4/CD8 ratio ; Rat ; Tcrb ; Polymorphism
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    Topics: Biology , Medicine
    Notes: Abstract. Three rat BV13S1 alleles (T-cell receptor β-chain variable gene 13) were characterized by new BV13S1-allele specific monoclonal antibodies (18B1 and 17D5) and sequence analysis of expressed and genomic BV13S1. Two alleles were functional and designated BV13S1A1 present in strains LEW, BUF, PVG, and BV13S1A2 present in BN and WF. Their products differed by six amino acids, two of them in complementarity-determing region (CDR)1 and one in CDR2. A third nonfunctional allele, BV13S1A3P, was found in strains F344 and DA. Apart from a single nucleotide insertion, it was identical to BV13S1A2. All 12 rat strains tested showed association of TCRBC1 with BV8S2/4 alleles but not with the BV13S1 alleles, which may reflect a different gene order of the rat BV compared to mouse. BV13S1A1-encoded T-cell receptors (TCRs) which bind both monoclonal antibody (mAb) 18B1 and mAb 17D5 are over-represented in the CD4 lymphocyte subset. BV13S1A2-encoded TCRs which are stained by mAb 18B1 but not by mAb 17D5 show a slight CD8-biased expression. Preferential usage of BV13S1A1-positive TCRs by CD4 but not by CD8 cells in (LEW×WF)F1 hybrids and cosegregation of BV13SA1 and increased frequency of BV13S1 TCR-positive CD4 cells in a (LEW×BN)×BN backcross suggest structural differences of the two allelic products as the reason for their contrasting CD4/CD8 subset bias.
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  • 82
    ISSN: 1432-1211
    Keywords: Key words CD1 ; Rat ; Gene ; Organization ; Polymorphism
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    Topics: Biology , Medicine
    Notes: Abstract  The non-major histocompatibility complex (MHC)-encoded CD1 family has recently emerged as a new antigen-presenting system that is distinct from either MHC class I or class II molecules. In the present study, we determined the genomic structure of the rat CD1 locus. It was extremely similar to mouse CD1 genes, especially to CD1D1. The 5′ flanking region of the CD1 gene contained the binding motifs for two cytokine-inducible transcription factors, NF-IL2-A and NF-IL6. Some regulatory elements found in MHC class I genes (enhancer A, enhancer B, and the IFN response element) were absent. It is of interest that a tyrosine-based motif for endosomal localization found in the human CD1b cytoplasmic tail was encoded by a single short exon which was conserved in all CD1 molecules except for CD1a. Southern blot and direct sequencing analyses of inbred rat strains suggested very limited polymorphism in the 5′ region where a hydrophobic ligand-binding groove is encoded; a single base substitution resulted in amino acid alteration of alanine (GCT) to valine (GTT) at codon 119. Comparison of the overall exon-intron organization of CD1 genes revealed that the length of the intron was also characteristic to each of the two classes of CD1 genes, classic CD1 and CD1D; such categorization has hitherto been made according to the sequence similarity of the coding region. This finding provides further support for the hypothesis that the two classes have different evolutionary histories. In contrast to the complete absence of the classic CD1 in rats and mice, the entire region of nonpolymorphic CD1D has been conserved through mammalian evolution. Similar functional properties of rodent CD1 and human CD1d are implied.
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  • 83
    ISSN: 1432-1211
    Keywords: Key words Class II MHC sequence ; Rat ; Cloning ; RT-PCR ; Polymorphism
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  • 84
    ISSN: 1432-1211
    Keywords: Key words RT1.S3 ; Grc ; MHC ; Class I ; Rat
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  • 85
    ISSN: 1432-119X
    Keywords: Endothelin-A receptor ; Endothelin-B receptor ; Rat ; Pulmonary fibrosis ; Immunohistochemistry ; Quantitative PCR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: AbstractPulmonary fibrosis is characterized by excessive extracellular matrix deposition with concomitant loss of gas exchange units, and endothelin-1 (ET-1) has been implicated in its pathogenesis. Increased levels of ET-1 from tissues and bronchoalveolar lavage have been reported in patients with pulmonary fibrosis and in animal models after intratracheal bleomycin. We characterized the cellular distribution of alveolar ET receptors by immunohistochemistry in bleomycin-induced pulmonary fibrosis in the rat and determined the regulation by bleomycin of ET receptor mRNA expression in isolated alveolar macrophages and rat lung fibroblasts. We found significant increases in the numbers of fibroblasts and macrophages at day 7 compared to day 28 and control animals. ETB receptor immunoreactivity was observed on fibroblasts and invading monocytes. Isolated fibroblasts expressed both ETA and ETB receptor mRNA, and ETA receptor mRNA was upregulated by bleomycin. Isolated resident alveolar macrophages expressed neither ETA nor ETB receptor mRNA which were also not induced by bleomycin. We conclude that, while ETB receptor stimulation of fibroblasts and monocytes recruited during bleomycin-induced lung injury exerts antagonistic effects on fibroblast collagen synthesis, the observed increase in the number of fibroblasts in vivo and upregulation of fibroblast ETA receptor mRNA by bleomycin in vitro point to a predominance of the profibrotic effects of ET receptor engagement.
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  • 86
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    International journal of biometeorology 32 (1988), S. 17-20 
    ISSN: 1432-1254
    Keywords: Epilepsy ; Electromagnetic fields ; Rat ; Audiogenic seizure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract In order to study the possible association between epileptic seizures and natural electromagnetic fields, 32 female audiogenic seizure (AGS)-susceptible rats were exposed to simulated 10 kHz and 28 kHz atmospherics and to a sinusoidally oscillating magnetic field with a frequency of 100 Hz and field strength of 1 A/m. After the electromagnetic exposure, seizures were induced in the rats with a sound stimulus. The severity of the seizure was determined on an ordinal scale, the audiogenic response score (ARS). The time from the beginning of the sound stimulus to the onset of the seizure (seizure latency) and the duration of the convulsion was measured. No differences from the control experiments were found in the experiments with simulated atmospherics, but the 100 Hz magnetic field increased the seizure latency by about 13% (P〈0.02). The results do not support the hypothesis that natural atmospheric electromagnetic signals could affect the onset of epileptic seizures, but they suggest that AGS-susceptible rats may be a useful model for studying the biological effects of electromagnetic fields.
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  • 87
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    International journal of biometeorology 41 (1998), S. 101-104 
    ISSN: 1432-1254
    Keywords: Key words Space flight ; Rat ; Plantaris muscle ; GLUT-4 ; Citrate synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract  The effects of 14 days of space flight on the glucose transporter protein (GLUT-4) were studied in the plantaris muscle of growing 9-week-old, male Sprague Dawley rats. The rats were randomly separated into five groups: pre-flight vivarium ground controls (PF-VC) sacrificed approximately 2 h after launch; flight groups sacrificed either approximately 5 h (F-R0) or 9 days (F-R9) after the return from space; and synchronous ground controls (SC-R0 and SC-R9) sacrificed at the same time as the respective flight groups. The flight groups F-R0 and F-R9 were exposed to micro-gravity for 14 days in the Spacelab module located in the cargo bay of the shuttle transport system – 58 of the manned Space Shuttle for the NASA mission named ”Spacelab Life Sciences 2”. Body weight and plantaris weight of SC-R0 and F-R0 were significantly higher than those of PF-VC. Neither body weight nor plantaris muscle weight in either group had changed 9 days after the return from space. As a result, body weight and plantaris muscle weight did not differ between the flight and synchronous control groups at any of the time points investigated. The GLUT-4 content (cpm/µg membrane protein) in the plantaris muscle did not show any significant change in response to 14 days of space flight or 9 days after return. Similarly, citrate synthase activity did not change during the course of the space flight or the recovery period. These results suggest that 14 days of space flight does not affect muscle mass or GLUT-4 content of the fast-twitch plantaris muscle in the rat.
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  • 88
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    International journal of biometeorology 34 (1990), S. 24-27 
    ISSN: 1432-1254
    Keywords: Cold-induced thermogenesis ; Peripheral nervous system ; Respiratory quotient ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract Cold-exposed rats show a reduction in the respiratory quotient which is indicative of a relative shift from carbohydrates to lipids as substrates for oxidative metabolism. In the present study, the effects of food deprivation and cold exposure on the respiratory quotient were observed. In addition, the involvement of the three main branches of the peripheral nervous system (sympathetic, parasympathetic, and somatic) was investigated by means of synaptic blockade with propranolol, atropine, and quinine, respectively. Both propranolol and quinine blocked the cold-induced decrease in respiratory quotient and increase in heat production, whereas atropine had only minor and very brief effects. It is concluded that both the sympathetic and somatic branches are involved in the metabolic changes associated with cold-induced thermogenesis and that the increase in metabolic heat production involves a shift from carbohydrate to lipid utilization irrespective of which of the two branches is activated.
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  • 89
    ISSN: 1432-1254
    Keywords: Atmospherics ; Carrageenan inflammation ; Rat ; Susceptibility ; Correlations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract Between the mean daily density of 28 kHz atmospherics and the onset of epileptic fits there is a highly significant correlation coefficient (r) of 0.30; there is a negative coefficient of −0.20 between the fits and the mean daily density of 10 kHz atmospherics. The onset of heart infarction is correlated with 28 kHz atmospherics (r=0.15). Furthermore, we have discovered that sudden deafness is also correlated with certain configurations of atmospherics. In this paper we report the following correlation coefficients between the inflammatory reaction of rats to a carrageenan injection (rci) into a hind paw and the mean daily pulse rate of atmospherics of the same day:r=0.49 for the 8 kHz atmospherics (P〈0.02) andr=0.44 for the 10 kHz atmospherics (P〈0.04). The correlations between rci reaction and other atmospherics (12 and 28 kHz) are smaller and not significant. By the method of multiple linear regression we found a multipleR=0.54 between rci reaction and the 8 and 10 kHz atmospherics (the regression function for the rci reaction is 0.15+0.004×8 kHz+0.002×10 kHz,P〈0.05).
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  • 90
    ISSN: 1432-1211
    Keywords: Key words CD4 ; Rat ; LEC ; thid ; Chromosomal mapping
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  • 91
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    Current genetics 23 (1993), S. 15-18 
    ISSN: 1432-0983
    Keywords: Yeast ; Rat ; Ribosomal protein ; 60S Ribosomal subunit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This communication reports on a single-copy gene of Saccharomyces cerevisiae which is homologous to the rat ribosomal protein gene L21. The yeast and the rat genes show 59% identity in DNA sequences and in the predicted protein sequences. This yeast gene is, therefore, assumed to code for an as yet unassigned ribosomal protein (URP1). The URP1 open reading frame is 480 nucleotides long and can encode a protein of about Mr 18 200. Like most of the other known ribosomal protein genes, URP1 is interrupted by an intron in its 5′ terminal part and it is preceeded by upstream sequence elements which usually regulate transcription of these genes. Northern blot analysis reveals that the URP1 gene is actually expressed in vivo.
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  • 92
    ISSN: 1432-1351
    Keywords: Rat ; Melatonin ; Circadian rhythm ; 5-hydroxytryptophan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The rhythm in melatonin production in the rat is driven by a circadian rhythm in the pineal N-acetyltransferase (NAT) activity. Rats adapted to an artificial lighting regime of 12 h of light and 12 h of darkness per day were exposed to an 8-h advance of the light-dark regime accomplished by the shortening of one dark period; the effect of melatonin, triazolam and fluoxetine, together with 5-hydroxytryptophan, on the reentrainment of the NAT rhythm was studied. In control rats, the NAT rhythm was abolished during the first 3 cycles following the advance shift. It reappeared during the 4th cycle; however, the phase relationship between the evening rise in activity and the morning decline was still compressed. Melatonin accelerated the NAT rhythm reentrainment. In rats treated chronically with melatonin at the new dark onset, the rhythm had already reappeared during the 3rd cycle, in the middle of the advanced night, and during the 4th cycle, the phase relationship between the evening onset and the morning decline of the NAT activity was the same as before the advance shift. In rats treated chronically with melatonin at the old dark onset or in those treated with melatonin 8 h, 5 h and 2 h after the new dark onset during the 1st, 2nd and 3rd cycle, respectively, following the advance shift, the NAT rhythm reappeared during the 3rd cycle as well but in the last third of the advanced night only. Neither triazolam nor fluoxetine together with 5-hydroxytryptophan administered around the new dark onset facilitated NAT rhythm reentrainment after the 8-h advance of the light-dark cycle.
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  • 93
    ISSN: 1432-1211
    Keywords: Key words Eotaxin ; Chemokine ; Eosinophil ; Lung ; Rat
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  • 94
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    Astrophysics and space science 224 (1995), S. 81-84 
    ISSN: 1572-946X
    Keywords: Chemistry ; Depletions ; Shocks ; IRAS 05338-0624 ; NGC 1333 IRAS 4
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High resolution interferometer and single-dish observations of young, deeply embedded stellar systems reveal a complex chemistry in the circumstellar environments of low to intermediate mass stars. Depletions of gas-phase molecules, grain mantle evaporation, and shock interactions actively drive chemical processes in different regions around young stars. We present results for two systems, IRAS 05338-0624 and NGC 1333 IRAS 4, to illustrate the behavior found and to examine the physical processes at work.
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    Astrophysics and space science 216 (1994), S. 153-154 
    ISSN: 1572-946X
    Keywords: Chemistry ; Molecular Hydrogen ; Cloud Models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Observations of the CO J=1-0 line are commonly used as a tracer for molecular material in clouds. The ratio of the H2 column density to the integrated intensity of this line,X, is often taken to be constant, despite theoretical and observational uncertainty. We have tried to identify how this ratio depends on cloud parameters, testing a simple theoretical argument suggesting its invariance with respect to density. The apparent constancy can be understood if clouds are clumpy on scales of Av ≈ 1-2 mag.
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  • 96
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    Boundary layer meteorology 85 (1997), S. 197-222 
    ISSN: 1573-1472
    Keywords: Turbulence ; Chemistry ; Closure ; Convective boundary layer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We study the interactions of chemistry and turbulent mixing of tracersin the convective boundary layer with a second-order closure model,including higher order chemistry terms. In order to limit the number of predictive equations we prescribe the profiles for ¯w¯Θ, ¯w¯θ ¯θ and the lengthscale l. However, for model validation we treat temperature and humidity asinert tracers, and compare the results with profiles observed during theAir Mass Transformation Experiment, and with similarity expressions for thesurface layer. We find good agreement of the mean profiles, but the (co-)variances are slightly underpredicted. Furthermore, the model usesdiagnostic equations expressing third moments of concentration in terms ofsecond moments and their vertical derivatives. They are compared withlarge-eddy model results, showing good agreement and, therefore, thesimplifications are justified. The model is applied to the transport of two gases subject to one bimolecular reaction. The importance of concentration correlations on themean transformation rate is studied. For two gases diffusing in oppositedirections we find for moderate and fast chemistry a 50% and90% decreased transformation rate due to the negatively correlatedconcentrations. These values are similar to large-eddy results of Schumannand Sykes et al. For two bottom-up tracers we find that the covariance ofboth reactive species is either positive or negative, increasing or reducingthe effective transformation rate depending on the Damköhler number (the ratio of the turbulent and the chemistry timescale). A significantdirect influence of chemistry on the flux divergence is found in bothcases. According to the model the effective transport to mid-levels of theboundary layer is increased when two reactive tracers diffuse in oppositedirections, and decreased in the case of two bottom-up tracers.
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  • 97
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    Springer
    Cell & tissue research 110 (1970), S. 97-107 
    ISSN: 1432-0878
    Keywords: Muscle Spindles ; Different types of sensory endings ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In einer Muskelspindel der Ratte, die an einer Serie alternierender Semidünn- und Ultradünnquerschnitte untersucht wurde, wurden zwei benachbart an „nuclear chain“-Fasern gelegene Nervenendformationen unterschiedlicher Bauweise festgestellt. Die beiden Endformationen sind mit ein und derselben Nervenfaser der Gruppe II verbunden und daher als Bestandteile einer sekundären sensorischen Endigung zu betrachten. Die Nervenendformation an einer der beiden „nuclear chain“-Fasern hat anulo-spirale Form. Die Nervenendformation an der anderen „nuclear chain“-Faser weist am Querschnittsbild eine Anzahl von Axonen auf, die zwischen Plasmalemm und Basalmembran der intrafusalen Muskelfaser eng aneinanderliegen. Nicht alle Axonquerschnitte stehen in direktem Kontakt mit der intrafusalen Faser. Das terminale Axon scheint sieh nach Eintritt unter die Basalmembran der intrafusalen Faser mehrfach in relativ dünne Äste unregelmäßigen Verlaufs zu teilen. Diese Form der Endigung könnte ein Korrelat der sog. „flower spray“-Endigung im Sinne Ruffinis (1898) darstellen. Die beiden morphologisch unterschiedlichen Endformationen innerhalb der sekundären Endigung gleichen einander und den Endformationen der primären Endigung bezüglich folgender Ultrastrukturmerkmale: 1. Es besteht synaptischer Kontakt zwischen Axon und intrafusaler Muskelfaser (synaptischer Spalt durchschnittlich 200 Å) ohne Zwischenlagerung von Basalmembranmaterial; 2. die terminalen Axonabschnitte liegen direkt unter der Basalmembran der intrafusalen Muskelfaser und sind nicht von Schwannschen Zellen bedeckt; 3. Mangel an synaptischen Bläschen; 4. desmosomenartige Verhaftungen zwischen Zellmembranen von Axon und intrafusaler Faser; 5. dyadenartige Anlagerungen des sarkoplasmatischen Retikulums an die Zellmembran der intrafusalen Faser im Bereich des synaptischen Spaltes. Nach unseren derzeitigen Vorstellungen sprechen diese Ultrastrukturmerkmale für eine rezeptorische Natur der beschriebenen Nervenendigungen.
    Notes: Summary In a rat muscle spindle transversally cut into a series of alternating semithin and ultrathin sections, two different forms of nerve terminations were found on two neighbouring nuclear chain fibres. The two nerve terminations were connected to the same group II nerve fibre and are consequently constituents of one particular secondary sensory ending. The nerve termination on one of the two nuclear chain fibres is of the anulo-spiral type. The nerve termination on the second nuclear chain fibre shows a number of axons lying closely together between plasma membrane and basement membrane of the intrafusal muscle fibre. Not all of these axons are in direct contact with the intrafusal fibre. The terminating nerve fibre seems to be divided into several branches of rather small diameters and irregular courses. It is suggested that this kind of termination could be a correlate of the so-called “flower spray” type of sensory endings in muscle spindles. The two morphologically different nerve terminations in the secondary ending have the following ultrastructural characteristics in common with those of the primary ending: 1) Synaptic contact between axon and intrafusal muscle fibre (synaptic gap about 200 Å) without interposition of basement membrane material; 2) terminal axons located beneath the basement membrane layer of intrafusal muscle fibres without covering by Schwann cells; 3) lack of synaptic vesicles; 4) desmosome-like structures between plasma membranes of axon and intrafusal muscle fibre, and 5) dyads of the sarcoplasmic reticulum adjacent to the synaptic cleft. According to present knowledge these features indicate that all of these endings are sensory ones.
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  • 98
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    Springer
    Cell & tissue research 116 (1971), S. 151-156 
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Innervation ; Receptors ; Rat ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the adrenal cortex of the rat and the pig is investigated with the electron microscope. Nerve fibers containing synaptic and two types of dense-cored vesicles come into contact with endocrine cells. There are no specialized pre- and postsynaptic membranes. The synaptic cleft is about 200 Å wide. Generally the basement membrane between nerve and cell is absent. These observations are discussed on the base of more recent experimental findings. Small fibers having an average diameter of about 0.2 to 0.5 μ and containing only tubules and filaments are considered to represent parts of an afferent nervous system.
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  • 99
    ISSN: 1432-0878
    Keywords: Adrenergic neurons ; “Short” and “long” systems ; Pre- and postnatal development ; Peripheral organs ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The adrenergic innervation in the submaxillary gland, heart, kidney, small intestine, and accessory male genital organs and the development of the adrenal chromaffin cells and the sympathetic ganglia were studied in the rat from 15 days post coitum to 16 days post partum using the fluorescence histochemical method of Falck and Hillarp. The postnatal development of the noradrenaline concentrations in the heart and vas deferens was followed by fluorometric determinations. At about 15 days post coitum, the anlagen of the sympathetic chains were well visible in the form of two dorsal segmented columns of small branching sympathicoblasts exhibiting an intense catecholamine fluorescence. In the midline, ventrally to these two anlagen, another column of sympathicoblasts developed; this seemed to give rise to the prevertebral ganglia and to the short adrenergic neurons supplying the internal genital organs. At the level of the adrenal anlagen, small intensely fluorescent chromaffin cells were collected in two bilateral groups which became enclosed by adreno-cortical cells. This enclosure was, however, not complete even at two weeks post partum. Bundles of growing sympathetic nerves were visible in the periphery of the various organs studied at 19–21 days post coitum. A terminal innervation of the organs suggestive of a functional transmitter mechanism did not start to establish until at or immediately after birth. The final pattern of innervation was usually reached at about one week post partum, and the following development proceeded largely in the form of a quantitative increase in the number of nerves participating in the innervation apparatus. The adult level of noradrenaline in the heart and vas deferens was reached three to five weeks after birth. The small intestine was an exception in that the final pattern of innervation in the wall was attained immediately after birth. There was no overt difference in the rate of development of the terminal sympathetic innervation in organs supplied by short adrenergic neurons (accessory male genital organs) compared to the innervation of the submaxillary gland, heart and kidney, which receive classical long adrenergic neurons.
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  • 100
    Electronic Resource
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    Springer
    Cell & tissue research 119 (1971), S. 58-67 
    ISSN: 1432-0878
    Keywords: Ovary ; Rat ; Fowl ; Granulosa cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The granulosa cells of the ovarian follicle of the rat and the domestic fowl have been studied with the light and electron microscope. The nuclei of the granulosa cells were irregular with indentations and large in proportion to the cytoplasm of the cell. The mitochondria had a dense, dark matrix with only few cristac. The Golgi apparatus was moderately developed, located towards the oocyte in a juxtanuclear position. The endoplasmic reticulum was rather sparse. Lipid droplets were only occasionally encountered. Microtubules were regularly observed. The functions of the granulosa cells are discussed. Compared with the steroid-producing cells of the theca interna of the same follicles, the granulosa cells primarily are the nursing cells for the growing oocyte and mainly have the characteristics of protein forming cells.
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