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  • Bone  (45)
  • Chromatographie, Dünnschicht  (39)
  • Immunocytochemistry  (34)
  • Auxin  (30)
  • Springer  (148)
  • 1995-1999
  • 1980-1984
  • 1975-1979  (148)
  • 1925-1929
  • 1978  (67)
  • 1977  (81)
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  • Springer  (148)
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  • 1995-1999
  • 1980-1984
  • 1975-1979  (148)
  • 1925-1929
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  • 1
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    Calcified tissue international 22 (1977), S. 303-313 
    ISSN: 1432-0827
    Keywords: Osteoclasts ; Sedimentation ; Isolation ; Cells ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract A method is presented for separating osteoclasts from the heterogeneous population of bone and marrow cells. Cell suspensions were prepared from femora of young rabbits by mechanical dispersion. The starting cell suspension typically contained only 1.0%±0.5 osteoclasts. Following an initial 45 min of unit gravity sedimentation in a lucite chamber osteoclasts were primarily distributed in fractions 2–5. A second 45-min sedimentation of these pooled fractions yielded cell suspensions containing greater than 30% osteoclasts (as much as a 50-fold increase over starting percentages). Linear scan analysis, however, revealed that osteoclasts accounted for 73.14%±0.58 of the cell colume. Subsequent in vitro experiments demonstrated linear incorporation of3H-leucine into TCA precipitable protein for cells comprising the osteoclast fraction. Concomitant radiautographs revealed radioactive label in isolated osteoclasts.
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  • 2
    ISSN: 1432-0827
    Keywords: Bone ; Diphosphonates ; Bone resorption ; Bone formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Male rats weighing 100 g were assigned to groups and injected daily for 10 days with vehicle (control), 0.4, 2.0, 4.0, 10.0, or 20.0 mg/kg/day of ethane-1-hydroxy-1,1-diphosphonate (EHDP) or dichloromethylene diphosphonate (Cl2MDP). The proximal tibial metaphysis and epiphysis were assayed for changes in percentage of hard tissue and bone formation parameters. From the data, information about hard tissue resorption was deduced. All doses of Cl2MDP and doses of 2.0 mg EHDP/kg/day and greater caused significant increases in percentage of hard tissues with Cl2MDP being more effective than similar doses of EHDP in decreasing bone resorption. Osteoclast population parameters were increased with all doses of both Cl2MDP and EHDP with Cl2MDP having a greater effect than similar doses of EHDP. Decreases in the proliferation of the osteoprogenitor pool parallel the decreases in osteoblasts and bone formation parameters. These decreases in osteoprogenitor pool proliferation do not account for the increases with diphosphonates in osteoclast population parameters.
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  • 3
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    Calcified tissue international 23 (1977), S. 283-289 
    ISSN: 1432-0827
    Keywords: Bone ; Resorption ; Osteoclast ; Quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The stimulation of bone resorption, assessed by the release of45Ca from prelabeled bones, was associated with an increase in number of osteoclasts per bone section in parathyroid hormone (PTH)-treated bones, but not in lipopolysaccharide (LPS)-treated bones. By contrast the number of nuclei per osteoclast increased following LPS treatment, but was not affected by PTH. LPS-treated bones had more multinucleated cells, some having as many as 27 nuclei per osteoclast. More osteoclasts were adjacent to the bone collar in bones treated with LPS or PTH than in control bones. In LPS-treated bones this area also contained the largest osteoclasts, as determined by the greatest number of nuclei per osteoclast. The results suggest that LPS and PTH stimulate osteoclastic resorption by different mechanisms.
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  • 4
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    Calcified tissue international 23 (1977), S. 303-305 
    ISSN: 1432-0827
    Keywords: Albumin ; Bone ; Hydroxyapatite ; Plasma protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The extractability of125I-labelled plasma albumin from bone pieces and from powdered bone has been compared after both in vivo and in vitro incorporation. The results show that albumin is more readily extracted from bone pieces than from bone powder which implies that tissue disruption exposes additional protein adsorption sites. It is suggested that incorporation of plasma albumin into calcified matrix during bone formation occurs mainly as a result of its strong interaction with bone mineral.
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  • 5
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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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  • 6
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    Calcified tissue international 23 (1977), S. 1-5 
    ISSN: 1432-0827
    Keywords: Water ; Bone ; Homeostasis ; Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A short review is given of the water in bone. Various analyses of bone water content are discussed, and its possible location is considered in relation to the behaviour of water in isolated components of bone. Some of the difficulties encountered in examining such microscopic phenomena as water structure in a heterogeneous system such as bone are also discussed.
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  • 7
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    Calcified tissue international 24 (1977), S. 41-46 
    ISSN: 1432-0827
    Keywords: Lead salt ; Bone ; Mobilization ; Hypercalcemia ; Hyperphosphatemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The present study is an investigation of the mechanism of hypercalcemia and hyperphosphatemia induced by the intravenous injection of lead acetate (Pb-Ac). A total of 118 male rats were injected with 30 mg/kg of Pb-Ac, or with 16.5 mg/kg of sodium acetate as the control. The levels of serum calcium, phosphorus and lead were then determined at various time periods after the injections. Serum calcium and phosphorus levels increased with time after Pb-Ac injection and the maximum values of calcium (17 mg%) were found after 1 h and of phosphorus (13.5 mg%) after 30 min. Both calcium and phosphorus levels reverted to the normal range after 12 h. The maximum net rates of increase of calcium and phosphorus were found immediately after Pb-Ac injection. At that time, deposition of lead at the calcifying sites of bone and incisor dentin was demonstrated by a histochemical examination. In other experiments the changes in the calcium and phosphorus contents in the medium after shaking bone powder in serum with Pb-Ac in an in vitro system were studied. It was confirmed that the calcium and phosphorus were displaced from the bone mineral, the extent of the displacement being correlated with the concentration of the Pb-Ac added to the medium, and that these displacements were very rapid reactions. These results suggest that hypercalcemia and hyperphosphatemia following Pb-Ac injection results from a direct action of lead on the bone mineral.
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  • 8
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    Calcified tissue international 24 (1977), S. 209-214 
    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Plasma calcium ; Radiocalcium ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The net rate of loss of45Ca from plasma was monitored in normal, thyroparathyroidectomized (TPTX), and nephrectomized rats. Also studied was the effect of a 24 h intravenous infusion of PTH in TPTX rats. The45Ca was injected after an overnight fast and 1 to 4 h prior to the time the first blood sample was obtained. In normal rats, the net rate of loss of45Ca from plasma was slower than in TPTX rats for at least 12 h after radionuclide injection. Nephrectomy did not affect this difference between control and TPTX rats until 8 h after45Ca injection or about 18 h after nephrectomy. At this time a reversal occurred and the net rate of plasma45Ca loss in nephrectomized rats with parathyroids became faster than in TPTX nephrectomized rats. When PTH was infused at a constant rate (3 mU/g body weight/h) plasma calcium concentrations rose gradually for approximately 12 h after which a constant plasma calcium level was maintained with continued PTH infusion. During the period when plasma calcium concentrations were rising, the net rate of loss of45Ca from plasma was slower than in TPTX controls infused only with saline. However, when plasma levels stabilized, plasma45Ca disappearance rates changed such that the rate loss of45Ca from plasma became faster in PTH-infused than in TPTX controls. It is concluded that PTH increases calcium efflux from the same compartment in bone which receives calcium from plasma, thereby returning some recently deposited45Ca to plasma. In the non-equilibrated state, this returns additional45Ca to plasma causing anet decrease in the rate of loss of45Ca from plasma. However, in the equilibrated condition, when both calcium efflux from bone and influx into bone are in balance but at higher flux rates, PTH stimulates the diffusion of45Ca into other bone compartments.
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  • 9
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    Calcified tissue international 26 (1978), S. 47-49 
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; Calcospherites ; Mineralization ; Bone ; Dentin ; Cartilage ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Mineral particle cluster, corresponding to calcospherites or matrix vesicle-initiated clusters in calcifying cartilage and dentin and to collagen bundle-related mineralization in lamellar bone, have been isolated from NaOCl solutions used to dissolve the organic matrix in preparation of anorganic mineralizing fronts for scanning electron microscopy.
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  • 10
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    Calcified tissue international 26 (1978), S. 81-84 
    ISSN: 1432-0827
    Keywords: Osteoclasts ; Bone ; Resorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Osteoclastic bone resorption involves the solubilization of the mineral salts and the degradation of noncollagen bone matrix and collagen fibrils. As no recognizable collagen fibrils have ever been reported within cytoplasmic vacuoles in osteoclasts, it is generally assumed that the collagen fibrils are digested extracellularly in the resorption zone. The extent to which lysis occurs extracellularly and whether or not the osteoclasts phagocytose the degradation products remain to be established. In the present communication, a hypothesis is presented suggesting the possibility that osteoclastic resorption of bone involves the participation of two different cell types. According to this hypothesis, osteoclastic bone resorption is initiated by osteoclasts that demineralize areas of bone and degrade noncollagen bone matrix. After the osteoclasts have moved away or become partially detached from the demineralized site, the exposed collagen fibrils are phagocytosed by mononuclear, fibroblast-like or monocyte-derived cells.
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  • 11
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    Calcified tissue international 26 (1978), S. 155-161 
    ISSN: 1432-0827
    Keywords: Plasma protein ; Glycoprotein ; Bone ; Glucosamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Plasmaα 2HS-glycoprotein is specifically accumulated in calcified tissues. In the present studies this glycoprotein was isolated from plasma and after iodination with iodine-125 was injected intravenously into young rabbits. The tissue distribution and plasma disappearance rate of this radioactively labeled material were determined. Of the various tissues studied, bone showed the greatest retention of labeled glycoprotein expressed as percentage of the injected dose per gram tissue relative to the plasma content. The rate of loss of iodinatedα 2HS-glycoprotein from plasma was similar to that ofα 2HS-glycoprotein labeled endogenously by using14C-glucosamine or3H-glucosamine. The uptake of exogenously labeled3I-α 2HS-glycoprotein into bone tissue expressed as a percentage of the injected dose was similar to that of endogenously labeled14C-α 2HS-glycoprotein. These results suggest that the125I-labeled material can be used to study further the metabolism ofα 2HS-glycoprotein by bone tissue.
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  • 12
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    Calcified tissue international 26 (1978), S. 209-213 
    ISSN: 1432-0827
    Keywords: Mithramycin ; Bone ; β-Glucuronidase ; KT medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Mithramycin suppresses bone resorption. Its effect on the synthesis and release of β-glucuronidase (a referent for lysosomal enzymes) in mouse calvarial explants was studied in an in vitro culture system. A newly described medium (designated as KT medium) was introduced in this specific study. Mithramycin initially inhibited the release of β-glucuronidase into the medium and resulted in an ultimate accumulation of this enzyme in the bone. These results suggest that inhibition of bone resorption by mithramycin may be attributed to interference in release of lysosomal enzymes from bone cells.
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  • 13
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    Calcified tissue international 23 (1977), S. 185-188 
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; Bone ; Ultracrytomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Matrix vesicles were observed in femurs of 8-day-old chick embryos prepared by ultracryotomy. Some of the sections were subjected to ultramicroincineration. The unfixed tissues never came into contact with solutions, and thereby artifacts due to dissolution, redistribution, or rearrangement of the mineral constituents were avoided. In the osteoid, electron dense objects with the size and appearance of matrix vesicles were seen, although limiting membranes were not visible. After ultramicroincineration the vesicles were observed to contain small crystals and a less dense amorphous mineral material which may be the precursor of bone mineral. In addition, a ring of ash enclosed the crystalline and amorphous mineral and appeared to occupy the position of the vesicle membrane as seen in conventionally prepared material.
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  • 14
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    Calcified tissue international 24 (1977), S. 93-98 
    ISSN: 1432-0827
    Keywords: Magnesium ; Bone ; Mineral ; Chick embryo ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Using bone organ culture techniques, three concentrations of magnesium were evaluated for their effects on the mineral mass of embryonic chick tibiae incubated for 3 days with or without a metabolic inhibitor (1 mM iodoacetic acid) added to the media. Varying the medium Mg level from 0.3 to 3.0 mM had little effect on the net increase in mineral in live bones (without the inhibitor), but in dead tibiae (with the inhibitor) there was a marked net decrease in mineral deposition with increasing Mg concentration. Bone Mg mass varied directly with the level of Mg in the medium regardless of whether or not the tibiae were inhibited. Responsiveness to parathyroid hormone (PTH) with regard to mineral loss and increased lactate production was not affected by Mg even in tibiae incubated in Mg-free media. However, PTH-treated bones cultured in Mg-free media had a significantly elevated Mg mass, suggesting that the hormone may have a Mg-conserving effect on bone during severe Mg deficiency. The findings of this study support the hypothesis that bone cells regulate the level of Mg to which newly forming mineral is exposed and that PTH-responsiveness in embryonic chick tibiae is not dependent on the ambient Mg concentration.
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  • 15
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    Calcified tissue international 22 (1977), S. 9-17 
    ISSN: 1432-0827
    Keywords: Bone ; Fluoride ; Calcium ; Phosphorus ; Mechanical Strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Four groups of weanling rats were fed for 2 weeks on a diet sufficient or insufficient in calcium and/or phosphorus. Each group was divided into four subgroups which were offered distilled water supplemented with 0, 50, 75, or 150 ppm fluoride. High levels of fluoride in drinking water inhibited weight gain. This inhibition was less in rats deficient in phosphorus than when normal-phosphorus diets were offered. At a low level, fluoride was without any effect on bone ash, thickness of femoral cortical bone, and mechanical strength, as measured by maximal load, ultimate stress to breaking, and limit of elasticity. Modulus of elasticity was decreased. At higher levels fluoride tended to decrease most of these parameters, except in rats deprived of both calcium and phosphorus. The effect of fluoride was modified by lack of dietary calcium and/or phosphorus and appeared to be weaker in rats deficient in these nutrients. Lack of dietary calcium and/or phosphorus decreased bone strength more than did fluoride content of water and of bone mineral. Concentration of bone ash and thickness of femoral cortical bone were closely correlated with parameters of mechanical strength.
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  • 16
    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Plasma calcium ; Radiocalcium ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Acute changes in plasma calcium and45Ca were studied in young adult male thyroparathyroidectomized (TPTX) rats injected with moderate doses of parathyroid hormone (PTH). For plasma calcium changes, comparison was made between rats fasted or fed prior to PTH injection. For plasma45Ca changes, the effect of the time of administration of the radionuclide was also studied; this included rats injected with PTH 1 h after radionuclide (“1 h45Ca”), 18 h later (“18 h45Ca”) and more than 6 days later (“6 day45Ca”). The results can be summarized as follows: (1) Plasma calcium changes were greater when PTH was injected into “fed” rather than into “fasted” rats. (2) PTH always produced a relative increase (compared to controls tested concurrently) in plasma45Ca concentrations. This increase was the same in the “1 h45Ca” and the “18 h45Ca” groups. (3) Plasma45Ca rose at least temporarily following PTH injection in the “18 h45Ca” group. (4) The45Ca rise following PTH was always greater in “fed” than in “fasted” groups. (5) Plasma45Ca specific activities (S.A.) tended to rise in the “6 day45Ca” group and to fall in the “18 h45Ca” group, following PTH injection. However, the45Ca S.A. was always higher in fed than fasted groups. (6) In a few experiments in which32P was injected with45Ca, specific activity changes in plasma45Ca following PTH injection werenot accompanied by similar changes in32P specific activity. These results could not be adequately explained by PTH effects on bone resorption, but the data supported the postulate that PTH controls plasma calcium concentrations by increasing transport of calcium through the osteocyte-lining cell (osteoblast) bone cell complex from the bone fluid compartment to the ECF.
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  • 17
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    Calcified tissue international 22 (1977), S. 275-284 
    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Collagen ; Dentine ; Phosphoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Calcium-binding and biochemical studies have been applied to characterize the state of the carboxylate and protein-bound phosphate groups in the EDTA-demineralized matrices of rat bone and dentine. The organic phosphate and carboxylate content of demineralized bone is virtually identical to that of purified steer skin collagen whereas demineralized dentine has a significantly higher phosphate and carboxylate content, presumably due to the presence of an acidic non-collagenous phosphoprotein. Two classes of calcium-binding sites can be detected in demineralized bone, demineralized dentine, and purified, reconstituted collagen. The number of strong calcium-binding sites correlates with the number of protein-bound phosphate groups. Depending on the preparative procedure, seven to nine such sites (per collagen molecule) are present in dentine, and one to two in the purified reconstituted collagen and in bone. The binding constant for the dentinal sites (1.1×104 M−1), however, is 20 times greater than that for bone or reconstituted collagen fibrils from skin. We tentatively conclude that the strong calcium-binding site in bone and reconstituted collagen is of the form protein-PO 4 − Ca++ whereas in dentine it is of the form the weak binding sites in bone and dentine are of the form protein-COO-Ca++; and that approximately 160 of the 217 carboxylate groups of the collagen molecules of dentine or bone are present as electrostatic linkages of the form protein-COO−+H3N-protein.
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  • 18
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    Calcified tissue international 22 (1977), S. 315-327 
    ISSN: 1432-0827
    Keywords: Bone ; Bioelectricity ; Strain ; Locomotion ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Using wet dead specimens it was possible to show that the size and form of strain-related electrical potentials on the surface of sheep radii were related both to the amount of strain, and the strain rate, over the range of these recorded during locomotion. Using the same electrode and amplifier system in vivo changes in surface strain and surface charge were recorded from the radius of three sheep during locomotion. During slow locomotion electrical changes were negligible. At medium speed they were most variable, and profoundly influenced by small alterations in the timing and pattern of strain change. When locomotion was fast the electrical waveform reflected fairly faithfully the changes in strain on the bone surface.
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  • 19
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    Calcified tissue international 22 (1977), S. 329-331 
    ISSN: 1432-0827
    Keywords: Bone ; Fracture ; Mineral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The bone mineral content was measured by gamma absorptiometry in patients who had sustained fractures of the upper limb. Measurements were taken on the shafts of the forearm and in the trabecular bone immediately proximal to the wrist. Fractures of the surgical neck of the humerus and fractures of the shaft of the humerus did not significantly influence the bone mineral content of the ipsilateral forearm. Fracture of the radius and the ulna, however, caused a 15% loss of the bone mineral content in the trabecular bone proximal to the wrist, whereas the mineral content on the shafts of the fractured forearms increased or decreased depending on the fracture site. The findings suggest that measurements of bone mineral content of the forearm are not necessarily invalidated if there has been a fracture of the same limb. Only if the forearm itself is fractured should measurements on this site be avoided.
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  • 20
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    Calcified tissue international 25 (1978), S. 37-43 
    ISSN: 1432-0827
    Keywords: ESR ; Radiation free radicals ; CO3-Apatites ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Exposure of bone mineral to X-rays generates free radicals. These are usually very labile, but can be stabilized at liquid nitrogen temperatures for study by electron spin resonance spectroscopy. The free radicals thus detected in the present study included one with resonances arising from an electron excess center and 2 species with electron-deficit centers: a phosphate anion radical and a radical associated with carbonate. Each of these radicals seemed to be located chiefly at the mineral surface and was sensitive to the surface environment. Presence of an organic phase, as in whole bone, modified free radical production in a manner that suggests interference with the formation of electron deficit centers. Comparison with other synthetic minerals suggests that precipitated carbonateapatites are good models for bone mineral.
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  • 21
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    Calcified tissue international 23 (1977), S. 215-223 
    ISSN: 1432-0827
    Keywords: Amorphous mineral ; Bone ; Electron microscopy ; Ultracryotomy ; Ultramicro-incineration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The fine structure of the extracellular phase of avian medullary bone and embryonic chick femur was examined in thin sections prepared by ultracryotomy and ultramicroincineration. Since contact with solutions was completely avoided, little or no loss or dislocation of mineral constituents could occur. Amorphous bone mineral (ABM) was present in two forms: as 15–30 nm spheres and as a structure-free haze. Removal of all organic material by low temperature ashing left the ABM intact. Crystals were usually associated with the ABM. In newly ossifying regions clusters or nodules of randomly oriented crystals and ABM appeared to coalesce when they reached approximately 1 μm in diameter. In highly calcified regions crystals appeared to be oriented along collagen fibers. ABM did not appear to be associated with collagen. Unmineralized collagen was visible in osteoid after staining with dry OsO4 vapor and it appeared to be diverted around nodules. Structures which resembled matrix vesicles were present. Selected area electron diffraction patterns indicated the presence of hydroxyapatite.
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  • 22
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    Calcified tissue international 25 (1978), S. 227-232 
    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Bone ; Calcium ; Chick embryo ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The purpose of this study was to measure in an in vitro system the movement of Ca and phosphate (Pi) out of bone when treated with parathyroid hormone (PTH). Tibiae from 13-day chick embryos were incubated for up to 8 h in a defined medium containing 1.8 mM Ca. Medium samples were collected every 2 h and were analyzed for Ca, Pi and lactate. Net effluxes from the bones were calculated. When bones were incubated with PTH in the medium (1 U/ml), net Ca efflux was increased 44, 60 and 100% at 4, 6 and 8 h, respectively. At no time was net Pi efflux affected by the hormone. The well known PTH-stimulated lactate production was not seen until 8 h. Lower doses of PTH (0.1 and 0.3 U/ml) were also effective. Comparing PTH (1 U/ml) responsiveness at higher (2.2 mM) and lower (0.9 mM) medium Ca concentrations, showed that with 2.2 mM Ca no increased Ca efflux was seen, while with 0.9 mM Ca significant elevation in medium Ca occurred 2 h sooner than in the experiments using 1.8 mM Ca. In another experiment, varying the medium Pi level from 1 to 2 mM had no effect on the Ca response to PTH. In neither experiment was Pi release affected by PTH. The results of this study have led to the following conclusions: (1) PTH acts on bone to cause an early dose related increase in net Ca efflux; (2) the effect is specific for Ca, since it is not accompanied by an increased Pi efflux, and may be saturated by raising the medium Ca level; and (3) PTH-stimulated Ca efflux in this system is not correlated with, and is probably not a result of increased lactate production.
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  • 23
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    Calcified tissue international 25 (1978), S. 233-240 
    ISSN: 1432-0827
    Keywords: Bone ; Bone resorption ; Albumin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A fraction (brA), which causes resorption of fetal rat bones in vitro, has been concentrated from bovine serum albumin by anion exchange column chromatography on DEAE Sephadex. This active fraction has also been prepared using DEAE Sephadex A-50 by a batch method with a 0.09M NaCl, 0.1M TRIS buffer, pH 8.35. BrA was 10–30 times more potent than the original albumin. The retained material, which constitutes the bulk of the protein and has less activity than the original albumin, elutes with 0.45M NaCl. Similar treatment of serumα,β or γ globulins does not yield brA. Further enhancement of the bone resorbing activity of brA can be obtained with (NH4)2SO4 fractionation or extraction with CH3OH∶CHCl3. Heating at 55° C for 2 h or at 100° C for 10 min does not affect the activity; overnight incubation with protease destroys the bone resorbing effect. The bone resorbing activity is not removed by dialysis and does not correlate with the protease activity of the fraction. The action of brA is inhibited by 3 mM PO4, 1 μg/ml calcitonin or glucagon, 10−7 M dexamethasone or 0.02 μg/ml actinomycin D. The bone resorbing activity of brA is partially inhibited by 10−7–10−5 M indomethacin. PTH did not elicit bone resorption when added to cultures incubated in chemically defined medium supplemented with 0.1 mg/ml brA. However, brA did not inhibit PTH-induced resorption.
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  • 24
    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Strontium ; Apposition ; Tracer analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract 1. Evidence has accumulated that the rate of acceretion (A) of calcium to bone is the sum of two fluxes; apposition involving the laying down of new bone and augmentation which is the result of slow exchange of non-surface bone calcium with plasma calcium pools as the result of solid state diffusion. 2. A method has been devised for separating A into its two components. It requires the use of45Ca or, for clinical studies,85Sr as a calcium tracer. Studies which are initiated with a combined accretion rate-calcium balance study, are concluded with an estimate of the exponent of the power function which has been found to describe the whole body retention of tracer from the second month onward. 3. The impulse response function of the skeleton for the tracer is then calculated, making the assumption that in any uniform volume of bone, osteoclastic resorption is a first order process. Making in addition certain simplifying assumptions, which are shown to have a modest influence on the final results, a mean rate of bone resorption can be calculated using a development of the well known Stewart-Hamilton formula. The apposition rate is calculated as the sum of the resorption rate and the calcium balance. Augmentation and diminution, defined as equal and opposite exchange processes, are given by the difference between A and the apposition rate. 4. The results of our first thirteen studies in normal subjects and patients with metabolic bone disease are presented, together with analyses of some data from the literature. It is concluded that the development of an atraumatic method for measuring rates of bone formation and resorption in the whole body would be an important advance in the study of metabolic bone disease, and this work is presented so that critical comparisons may be initiated between this tracer method and independent histological methods for measuring these parameters.
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  • 25
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    Calcified tissue international 25 (1978), S. 249-254 
    ISSN: 1432-0827
    Keywords: Bone ; Oestrogens ; Oestrogen receptors ; Binding proteins
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    Topics: Biology , Medicine , Physics
    Notes: Summary Attempts were made to demonstrate the presence of specific oestrogen binding proteins (“receptors”) in bone cells. High speed cytosol preparations of bone were incubated with several concentrations of radioactive oestradiol alone and with radioactive oestradiol in the presence of a specific antioestrogen, Nafoxidine. Separation of bound and free oestradiol was carried out by dextran coated charcoal treatment and by sucrose gradient ultracentrifugation. Several types of bones likely to be oestrogen-sensitive were investigated: human femoral heads, human phalanx, rat and rabbit calvaria, humeri and femora of female rats. In all experiments we were unable to demonstrate the presence of specific oestrogen receptors in bone cell cytosol indicating that the direct effect of oestrogens on bone, if present, is not mediated by specific oestrogen receptors.
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  • 26
    ISSN: 1432-0827
    Keywords: Electron spin resonance ; Crystallinity ; Bone ; Osteons
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    Notes: Summary Several groups containing 10–15 isolated osteons differing in their degree of maturity were analysed. Samples were isolated from undecalcified human and bovine bone sections. The crystallinity coefficient, defined as the ratio of the number of radiation-induced paramagnetic defects in the crystalline lattice of hydroxyapatite to the total ash content, was calculated. The results were compared with measurements performed on fragments of total cortical bone, primary periosteal bone, and inner circumferential lamellar bone. The results show a higher crystallinity of fully calcified osteons as compared with that found at the initial stage of calcification. No differences in the ash content were observed between human osteons, from different stages of calcification evaluated morphologically and by X-ray absorption. These differences were evident when bovine osteons differing in their stage of calcification were compared. Human fully calcified osteons contain 60% ash and their crystallinity coefficient is 52.1. Human osteons at the initial stage of calcification contain 57% ash and their crystallinity coefficient is 40.6. The same parameters for fully calcified bovine osteons and for bovine osteons at the initial stage of calcification are 59% ash, 62.6 crystallinity coefficient and 46% ash, 43.0 crystallinity coefficient, respectively.
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  • 27
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    Calcified tissue international 24 (1977), S. 65-72 
    ISSN: 1432-0827
    Keywords: Bone ; Strength ; Tension ; Microstructure ; Osteon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Standardized human and beef femoral compact bone specimens were tested in tensile impact and the dynamic mechanical properties were determined. The microstructure of 45 beef and 47 human bone specimens were examined histologically to determine if there is a structural basis to account for strength differences in the bone samples. Strong negative correlations were obtained between the maximum stress and the percentage area of secondary osteons in each specimen. For human bone samples, the energy absorption capacity and the modulus of elasticity were also found to have strong negative correlations with the percentage area of secondary osteons present in each specimen. Linear regression equations were obtained describing the impact strength properties in terms of the percentage areas of secondary osteons and cavities in the samples. Fracture surfaces of the tested bone specimens were examined in a scanning electron microscope. Most surfaces exhibited a fairly rough texture indicating a quasi-cleavage type of failure. Fractographic analysis of bone fracture surface was helpful in understanding the micromechanics of bone fracture.
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  • 28
    ISSN: 1432-0827
    Keywords: Bone ; Density ; Composition ; Renal osteodystrophy ; Dogs
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    Notes: Summary Bone density and composition were studied in trabecular and cortical bone from control 2 and 4 year old beagles and those which had various degrees of renal failure as a result of perinatal irradiation. Changes in the two types of bone were qualitatively similar but consistently greater in trabecular bone. In a group identified as markedly uremic, the decrease (P〈0.025) from control levels in specific gravity was about 4 times greater in trabecular than in cortical samples. The decrease (P〈0.025) in grams of ash/ml was 9% in trabecular bone and 2% in cortical bone. These changes were associated with an increase (P〈0.001) in water content and, on a percent by volume basis, approximately equal decreases in ash (P〈0.025) and combustible matter (P〈0.025). In a mildly uremic group there were similar trends in mean values but the only significant difference was an increase (P〈0.001) in trabecular bone water.
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  • 29
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    Calcified tissue international 24 (1977), S. 201-208 
    ISSN: 1432-0827
    Keywords: Calcitonin ; Plasma calcium ; Radiocalcium ; Bone
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    Topics: Biology , Medicine , Physics
    Notes: Summary The effect of intravenous salmon calcitonin (SCT) infusion on the net rate of loss from plasma of recently injected45Ca has been studied in conscious fasted rats, some of which had been previously thyroparathyroidectomized (TPTX). The45Ca was injected 10 h prior to or 1 or 2 h after the initiation of the infusion. Salmon calcitonin (0.05–0.2 MRC mU/g body weight/h) infusion produced the expected hypocalcemia and hypophosphatemia. The drop in plasma calcium levels produced by the hormone was lowered further by the addition of phosphate to the infusate. Plasma45Ca changes, during SCT infusion, followed a biphasic pattern when the radionuclide injection preceded SCT infusion by 10 h. During the first part of the infusion, the rate of loss of45Ca from plasma was greater in SCT-treated than in control rats. Later, this pattern reversed, and the rate of loss of45Ca from plasma became slower in SCT-treated animals. If45Ca was injected after SCT infusion was initiated only the second phase of the biphasic effect was observed; i.e., disappearance of45Ca from plasma was slower in SCT-infused than in control rats. These data are considered to support the hypothesis that rapid and opposing calcium fluxes exist between bone fluid and plasma, and that calcitonin acts by decreasing the calcium efflux from bone fluid. The calcium moved in this efflux system includes some that has only recently entered bone fluid from plasma. This is the explanation given for the initial decrease in plasma45Ca concentrations following SCT infusion. The reverse effect in the second phase can be explained as the result of a secondary reduction in calcium influx to bone fluid from plasma.
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  • 30
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    Calcified tissue international 23 (1977), S. 113-114 
    ISSN: 1432-0827
    Keywords: Bone ; Absorption Spectra ; Collagen ; Hydroxyapatite
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    Topics: Biology , Medicine , Physics
    Notes: Summary Absorption spectra of human bone and its two major constituents (collagen and apatite) were obtained in the wavelength region extending from 2000 to 12,000 Å. In the last two cases a, minimum transmission (maximum absorption) was uniformly observed in the ultraviolet region. The two samples after exposure to ultraviolet radiations show a shift in the peak positions. Absorption peaks in the total bone spectra are not reproducible in its two constituents. After exposure to UV radiations the position of maximum absorption is displaced. A possible interpretation of the observed results is presented.
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  • 31
    ISSN: 1432-0827
    Keywords: Parathyroidectomy ; Diphosphonates ; Bone ; Collagen ; Hydroxyproline
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    Notes: Summary Disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) may impair mineralization and reduce turnover of bone. However, its administration has been shown to lead to an accumulation of osteoid in both man and the rat. Using rats, the effects of surgical parathyroidectomy and administration of EHDP (30 mg EHDP/kg body weight by subcutaneous injection daily for 5 days) upon bone composition, uptake of3H-proline into hydroxyproline in bone and the subsequent urinary excretion of labelled and unlabelled hydroxyproline have been compared. Both parathyroidectomized (PTX) rats and EHDP-treated animals accumulated more hydroxyproline in bone and excreted less total urinary hydroxyproline than sham-PTX control animals, the changes induced by EHDP being of greater magnitude than those induced by surgical parathyroidectomy. Skeletal buildup of hydroxyproline was associated with decreased catabolism of mature collagen rather than enhanced synthesis of hydroxyproline in bone. EHDP administration, although decreasing urinary excretion of newly synthesised hydroxyproline, did not alter the skeletal synthesis of hydroxyproline as measured by uptake of3H-proline. In all parameters measured, responses to EHDP were similar in PTX and sham-PTX rats. It is concluded that depression of parathyroid hormone mediated bone turnover may have contributed to, but did not fully account for, the lowering of bone turnover and changes in bone composition induced by EHDP in sham-PTX rats in the present experiment.
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  • 32
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    Calcified tissue international 26 (1978), S. 85-89 
    ISSN: 1432-0827
    Keywords: Bone ; Histology ; Microradiography ; Densitometry ; Computer
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    Topics: Biology , Medicine , Physics
    Notes: Summary A comparatively simple quantitative method for assessing bone morphology has been evolved. Microradiographs of thin sections of mandible have been scanned with a Joyce-Loebl double beam recording microdensitometer with a scanning autodensidater attachment, using a white beam. For each image the optical densities for all the pixels (picture elements) were divided into 10 groups. The limits of the division were fixed by the maximum and minimum densities occurring within the image. A computer generated map was produced which indicated the spatial distribution of the pixels within each group to which an arbitrarily chosen shading was attached. The number of pixels within each group is also shown on the map. The computer map was compared with the photomicrograph and, where necessary, the original section. The fractional area of hard tissue was then readily determined using the numerical values of each group of pixels.
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  • 33
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    Calcified tissue international 26 (1978), S. 139-142 
    ISSN: 1432-0827
    Keywords: Chemisorption ; Surface area ; Hydroxyapatite ; Bone ; Enamel
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    Topics: Biology , Medicine , Physics
    Notes: Summary The surface areas of three different samples of hydroxyapatite, samples of deproteinized bone, and samples of whole and deproteinized enamel were determined by adsorption of an adduct (the diglycidyl ether of bisphenol A with N-phenylglycine) from methylene chloride solution. In all cases, the surface areas of these samples agree well with those obtained by the BET (N2) method.
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  • 34
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    Calcified tissue international 25 (1978), S. 105-110 
    ISSN: 1432-0827
    Keywords: Progesterone ; 17β estradiol ; Testosterone ; Tissue culture ; Bone
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    Topics: Biology , Medicine , Physics
    Notes: Summary Although sex steroids are known to affect skeletal metabolism, their effects on bone collagen synthesis have not been studied. We have examined the direct effects of progesterone, 17β estradiol, testosterone, 5α dihydrotestosterone and dehydroepiandrosterone on bone collagen and noncollagen protein synthesis in cultures of calvaria obtained from 21-day fetal rats. Bones were incubated for 24 to 168 h and3H-proline was added for the last 2 h of culture. Incorporation of the label into collagenase-digestible protein (CDP)1 and noncollagen protein (NCP) was determined using repurified bacterial collagenase. Progesterone caused a dose dependent inhibition of the labeling of CDP at concentrations of 3×10−7 M to 10−5 M after 96 h of culture. A smaller inhibitory effect was observed on NCP. The inhibitory effect was slow in onset and persisted when bones were incubated for 48 h with progesterone and then transferred to control medium for 48 h. Progesterone also inhibited the incorporation of3H-thymidine and3H-uridine into fetal rat calvaria. After 24 h of culture, 17β estradiol and testosterone had no effects on the labeling of CDP and NCP. After 96 h, 17β estradiol had a small and inconsistent stimulatory effect on the labeling of CDP but testosterone had no effect. Neither hormone altered the inhibitory effects of parathyroid hormone, cortisol and progesterone. Dihydrotestosterone and dehydroepiandrosterone had no effects after 24 h and 96 h of culture. 17β estradiol, testosterone and dihydrotestosterone did not affect the incorporation of3H-uridine or3H-thymidine into fetal rat calvaria. Our studies indicate that progesterone is an inhibitor of bone collagen synthesis and estrogens and androgens are not major regulators of bone formation in vitro.
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  • 35
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    Calcified tissue international 22 (1977), S. 27-33 
    ISSN: 1432-0827
    Keywords: Protein ; Bone ; Blood plasma ; Dentine
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    Topics: Biology , Medicine , Physics
    Notes: Abstract The spectrum of plasma proteins present in human cortical bone and permanent dentine has been determined. One plasma glycoprotein, theαHS-glycoprotein, was found to be present at a high concentration in both bone and dentine and was shown to be concentrated in the mineralized tissues with respect to the other plasma proteins by factors of between 30 and 100. In this respect theαHS-glycoprotein is analogous to the G2B-glycoprotein and α-glycoprotein of bovine and rabbit b one, respectively. The binding ofαHS-glycoprotein and albumin to calcium phosphates generated within serum samples has been studied at different serum: precipitate ratios. In each case all theαHS-glycoprotein was removed from the samples and theαHS-glycoprotein was concentrated with respect to albumin by factors ranging from 370 at the highest serum: precipitate ratio to 25 at the lowest ratio. The plasmaαHS-glycoprotein concentrations of patients with Paget's disease of bone were shown to be substantially lower than the normal range, with significant negative correlation between theαHS-glycoprotein concentration and the plasma alkaline phosphatase activity.
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  • 36
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    Calcified tissue international 22 (1977), S. 183-189 
    ISSN: 1432-0827
    Keywords: Calcium ; Strontium ; Bone ; Mathematical modelling
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    Topics: Biology , Medicine , Physics
    Notes: Abstract 1. A method has been devised for comparing the impulse response functions of the skeleton for two or more boneseeking tracers, and for estimating the contribution made by measurement errors to the differences between any pair of impulse response functions. 2. Comparisons were made between the calculated impulse response functions for47Ca and85Sr obtained in simultaneous double tracer studies in sixteen subjects. Collectively the differences between the47Ca and85Sr functions could be accounted for entirely by measurement errors. 3. Because the calculation of an impulse response function requires fewera priori assumptions than other forms of mathematical analysis, and automatically corrects for differences induced by recycling of tracer and non-identical rates of excretory plasma clearance of tracer, it is concluded that differences shown in previous in vivo studies between the fluxes of*Ca and*Sr into bone can be fully accounted for by undetermined oversimplifications in the various mathematical models used to analyse the results of those studies.85Sr is therefore an adequate tracer for bone calcium in most in vivo studies.
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  • 37
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    Calcified tissue international 22 (1977), S. 219-226 
    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Bone ; X-ray Diffraction
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    Notes: Abstract Evidence relating to the existence of crystalline bone mineral in vivo is considered, and bone apatite crystal structure investigated using an x-ray powder diffraction technique. Specimens of femoral compacta excised post-mortem from male and female subjects ranging from 3 1/2 years to 87 years of age have been studied. Values of the ratio c/a of bone apatite crystal cell axes for females are significantly higher (p〈0.05) than for males. Moreover, significant change of c/a with age is observed for males (p=0.0005) but not for females (p=0.30). Differences in c/a are interpreted as indicating substitution of constituent ions in the bone apatite crystals.
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  • 38
    ISSN: 1432-0827
    Keywords: Diphosphonate ; Bone ; Osteoclasts ; Autoradiography
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    Topics: Biology , Medicine , Physics
    Notes: Abstract Male rats weighing 100 g were injected with vehicle (control group), 0.4 or 4.0 mg/kg/day of ethane-1-hydroxy-1,1-diphosphonate (EHDP). Beginning after 6 days of EHDP treatment all rats received six subcutaneous injections of3H-thymidine at 8 h intervals. The multiple labeling index of autoradiographically defined labeled cells was determined for the osteoprogenitor cells of the primary spongiosa of the proximal tibial metaphysis. The osteoclasts in the proximal tibial metaphysis were assayed for population parameters and incorporation of labeled nuclei at sequential intervals after the administration of3H-thymidine. After 6 days of EHDP pre-treatment the multiple labeling index of the osteoprogenitor cells was reduced with 4.0 mg/kg/day dose of EHDP. At the beginning of the experimental kinetic sampling period, after the 6 days of EHDP pre-treatment, EHDP treatment resulted in significant increases in the numbers of osteoclasts, nuclei per osteoclast profile, and total osteoclast nuclei. During the sampling period, the 4.0 mg/kg/day dose of EHDP caused further increases in the number of total osteoclasts. EHDP treatment caused a marked increase in the rate of incorporation and accumulation of3H-thymidine-labeled nuclei in osteoclasts. Thus, EHDP causes an accelerated rate of osteoclast production from precursor cells in spite of its ability to slow bone resorption. Although the origin of osteoclast nuclei is not clear, the kinetic data from this study suggests that osteoclast nuclei are not arising from osteoprogenitor cells or osteocytes in the EHDP-treated animals.
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  • 39
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    Calcified tissue international 23 (1977), S. 103-112 
    ISSN: 1432-0827
    Keywords: Albumin ; Polyvinylpyrrolidone ; Tissue fluid ; Bone
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    Topics: Biology , Medicine , Physics
    Notes: Summary The passage of tissue fluid through cortical bone has been investigated using radioactively labelled macromolecules as markers. The results suggest that in the cortex of young rabbit femur the movement of tissue fluid is in the same net direction as blood, mainly from the endosteal to the periosteal surface. Some albumin is incorporated from extravascular tissue fluid into calcified matrix at sites of bone formation. Polyvinylpyrrolidone, average molecular weight 35,000 is able to pass through extravascular tissue fluid in bone but isnot incorporated into calcified matrix. In rabbits made vitamin D deficient, much less albumin is retained in regions of bone formation than is the case with controls. Albumin adsorbs to the surface of calcium phosphate precipitates and it is suggested that this mechanism may be mainly responsible for its incorporation into bone.
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  • 40
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    Calcified tissue international 24 (1977), S. 143-149 
    ISSN: 1432-0827
    Keywords: Bone ; Periodontal ligament ; Bone resorption ; Aryl sulfatase ; Mineralization
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    Topics: Biology , Medicine , Physics
    Notes: Summary The distribution of aryl sulfatase in the rat periodontal ligament was investigated by ultrastructural histochemistry. In the periodontal ligament aryl sulfatase was localized specifically in osteoclasts and in vicinal perivascular macrophages. Macrophages associated with bone formation did not stain. The authors interpret this specificity as a potential marker for osteoclast differentiation from macrophages — or as a further indication of the capacity of macrophages to modulate their enzymatic complement in response to the environment. To explain the absence of aryl sulfatase in areas of bone formation we suggest that different sulfate esters are mobilized from resorbing and mineralizing matrices, and that only the enzyme associated with bone resorption is histochemically detectable with the artificial substrates currently used.
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  • 41
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    Calcified tissue international 24 (1977), S. 223-229 
    ISSN: 1432-0827
    Keywords: Enamel-cementum-morphology ; Immunocytochemistry ; Biochemistry
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    Topics: Biology , Medicine , Physics
    Notes: Summary The continuously erupting rabbit incisor tooth is normally thought of as having an enamel covered “crown” on its labial surface and a cementum covered “root” on its lingual surface. We have examined both surfaces of continuously erupting rabbit incisor teeth taken from near term embryos by a variety of means, including transmission and scanning electron microscopy, biochemical fractionation, and immunohistochemistry. In all cases, we could detect no qualitative difference in the early extracellular matrices taken from the labial and lingual surfaces of the teeth. Both matrices were shown to be composed of dentin and enamel, although the thickness and geometry of the enamel matrix on the lingual surface was somewhat different from that on the labial surface.
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  • 42
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    Calcified tissue international 24 (1977), S. 243-248 
    ISSN: 1432-0827
    Keywords: Paracrystallinity ; Hydroxyapatite ; Bone
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    Topics: Biology , Medicine , Physics
    Notes: Summary X-ray diffraction patterns from oriented bone sections show that the crystalline apatite content of untreated mature cortical bovine bone has, in fact, a paracrystalline structure (i.e., no long range order). There is anisotropy in both lattice distortions and the sizes of the coherently diffracting domains. The paracrystalline mean distance fluctuations, (g) were found to be 1.5 (±0.1)% and 2.9 (±0.2)% for the basal and prism planes respectively, the corresponding paracrystalline sizes being 220 (±20) and 70 (±10) Å. The paracrystalline structure became more ordered above 600°C, suggesting the association of hydroxyl and possibly carbonate and other ions with the paracrystalline structure. The paracrystalline model for bone apatite helps explain anomalies between X-ray and electron microscope measurements of crystal size and also some of the biological functions of the crystalline apatite.
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  • 43
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    Calcified tissue international 25 (1978), S. 29-35 
    ISSN: 1432-0827
    Keywords: Albumin ; Bone ; Growth retardation ; Osteomalacia
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    Topics: Biology , Medicine , Physics
    Notes: Summary 125I-labeled rat albumin injected intravenously into rats was taken up by growing bone. Some of this radioactive albumin could be removed from bone by washing with saline, the proportion so removed decreasing from 82.5% at 1 day to 7.4% at 8 days. Both the total radioactivity, and that remaining in bone after saline wash, were reduced when growth was slowed by alteration or restriction of the diet. Although the amount of125I albumin in rachitic bone was reduced, autoradiography showed that radioactivity was present in rachitic osteoid. Immunoprecipitation using anti-rat-albumin serum showed that about half of the radioactivity released from normal bone by EDTA was still attached to albumin. These results suggest that albumin plays some part in the growth of bone.
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  • 44
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    Planta 134 (1977), S. 145-149 
    ISSN: 1432-2048
    Keywords: Affinity labels ; Auxin ; Cell membranes ; Hormone Receptors ; Receptors ; Zea mays
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    Topics: Biology
    Notes: Abstract Two auxin analogues have been tested as affinity labels for auxin binding sites in coleoptile membranes of Zea mays L. Reacting the membranes at pH 8–9 with the diazonium salt of CAPA (2-chloro-4-aminophenoxyacetic acid) reduces their subsequent ability to bind NAA(1-naphthylacetic acid). Diazo-Chloramben (2,5-dichloro-3-aminobenzoic acid) is also effective in inhibiting NAA binding capacity and this inhibition is largely independent of reaction pH over the range pH 6–9. Similar experiments with sulphydryl reagents have shown that reaction of the membranes with p-mercuribenzoate (PMB) strongly inhibits subsequent auxin binding activity. Prior addition of NAA protects the binding sites against the action of diazo-Chloramben or PMB when the reactions are carried out at pH 6. From these results and from other considerations, several of the amino acid residues in the binding site environment have been tentatively assigned.
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  • 45
    ISSN: 1432-2048
    Keywords: Auxin ; Avena ; Helianthus ; pH drop ; Pisum ; Protoplast suspension
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    Topics: Biology
    Notes: Abstract Several indoleacetic acids, substituted in the benzene ring, were compared in the Avena straight growth bioassay. 4-Chloroindoleacetic acid, a naturally occurring plant hormone, is one of the strongest hormones in this bioassay. With an optimum at 10-6 mol l-1, it is more active than indoleacetic acid, 2,4-dichlorphenoxyacetic acid and naphthaleneacetic acid. 5-Chloro- and 6-chloroindoleacetic acids are very strong auxins as well. Other derivatives tested have a lower activity. 5,7-Dichloro- and 5-hydroxyindoleacetic acids have very low auxin activity at 10-4 mol l-1 and may be anti-auxins. Some of the derivatives were compared for their effect on pH decline in stem protoplast suspensions of Helianthus annuus L. and Pisum sativum L. The change of pH occurs without a lag period or with only a very short one. Derivatives which are very active in the Avena straight growth assay cause a larger pH decline than indoleacetic acid, while inactive derivatives cause effectively no pH decline.
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  • 46
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    Planta 140 (1978), S. 107-109 
    ISSN: 1432-2048
    Keywords: Auxin ; Leaf movement ; Phaseolus ; Pulvinus ; Turgor movement
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    Topics: Biology
    Notes: Abstract Auxin application to the upper side of the pulvinus of primary leaves of Phaseolus vulgaris L. promoted bending away from the place of application. The effect had a latency of less than 20 min and was specifically induced by substances known as active auxins in growth tests (indoleacetic and 1-naphthaleneacetic acid) but not by inactive auxin analogs (2-naphthaleneacetic, 3-indolepropionic and benzoic acid); 2,4-dichlorophenoxyacetic acid, and L-(-)-2,4-dichlorophenoxyisopropionic acid were of intermediate activity. Auxin-promoted bending was reversible and presumably caused by turgor increase in the treated cells.
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  • 47
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    Planta 140 (1978), S. 201-211 
    ISSN: 1432-2048
    Keywords: Auxin ; Cell elongation ; Coleoptiles ; Fusicoccin ; Zea
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    Topics: Biology
    Notes: Abstract To analyze early effects of auxin application, an apparatus was developed which continuously and simultaneously registered the curvature of 10 individual maize (Zea mays L.) coleoptiles. Resolution was less than 5 μm over a range of ±0.5 mm. The data were evaluated and plotted via paper tape and Hewlett-Packard-computer. Unilateral application of 3×10-5 M indoleacetic acid (IAA) resulted in a transient inhibition of growth on the side of application for ca. 10 min (Phase I), followed by a strong stimulation (Phase II). The phytotoxin fusicoccin (FC) caused an immediate stimulation of elongation. The initial negative reaction of Phase I is auxin-specific. Only active auxins such as IAA and 1-naphtaleneacetic acid produced this initial inhibition; chemical analogs-inhibitory or neutral in long-term growth tests, e.g. phenylacetic acid-did not show any significant effects on Phase I. When the coleoptiles were symmetrically preloaded with different levels of auxin, only a large step-up of subsequent unilateral auxin application resulted in a negative phase I; a small step-up led to an immediate positive reaction. The results are discussed in context with the parallel kinetics for various other auxin-induced reactions of coleoptile cells which have already been published.
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    Planta 136 (1977), S. 97-102 
    ISSN: 1432-2048
    Keywords: Acid growth ; Auxin ; Ethylene ; Fusicoccin ; Growth inhibition ; Lens ; Root growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both acid pH (4.0) and fusicoccin (FC) strongly stimulate root elongation in intact lentil (Lens culinaris Med.) seedlings. FC-induced elongation is apparently mediated by FC-enhanced H+ secretion since the toxin induces massive secretion of H+ in these roots after a latent period of less than 5 min. Auxin (indole-3-acetic acid) strongly inhibits elongation in control roots as well as acid-induced and FC-induced root elongation. Treatment of apical root segments with auxin causes only a slight apparent uptake of H+ and has no inhibitory effect on FC-induced H+ secretion, whether the hormone is given before or after the toxin. Auxin induces ethylene production in excised roots of lentil but the latent period is at least 30 min while inhibition of root elongation by IAA is maximal within 30 min. It is concluded that the inhibitory action of auxin on acid-and fusicoccin-induced root elongation is a direct effect, independent of auxin-induced ethylene production or auxin-mediated modification of cell-wall pH.
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  • 49
    ISSN: 1432-2048
    Keywords: Abelmoschus ; Auxin ; Gibberellin ; Root formation
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    Topics: Biology
    Notes: Abstract Indole-3-acetic acid (IAA) and gibberellic acid (GA3) enhanced the formation of roots on the stem cuttings of Abelmoschus esculentus. The effect increased considerably when both IAA and GA3 were applied together.
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  • 50
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    Planta 138 (1978), S. 107-110 
    ISSN: 1432-2048
    Keywords: Auxin ; Nitrogen fixation (asymbiotic) ; Pisum ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Treatment of epicotyls of dark-grown pea (Pisum sativum L.) seedlings with indole-3-acetic acid causes swelling of the tissue. Application of Rhizobium to the cut surface of the swollen tissue results in the development of an “infection”. The infection spreads in the cortical cells and proceeds 2–3 mm deep into the stem within 3–4 days. An acetylene reduction assay used for detecting nitrogen-fixation capacity of the infected tissue was negative at 10% [O2]; however, if [O2] was reduced to below 1%, some activity could be detected. Ultrastructural observations indicate that the cytoplasmic contents of the infected cells are destroyed and no membrane structure around the bacteria is formed during this infection. Rhizobium does not appear to have developed any symbiotic relationship with the host. Failure to develop symbiosis appears to result in a parasitic or saprophytic association and the nitrogen fixed under such conditions may not be of any use to the plant.
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  • 51
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    Planta 138 (1978), S. 181-184 
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Auxin ; Cannabis ; Cytokinin ; Flowers (sex) ; Gibberellin ; Sex expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Application, through the root system, of growth regulators to hemp (Cannabis sativa L.) plants having 2–3 pairs of visible leaves caused pronounced shifts of sex expression in the adult individuals. Treatment with gibberellic acid (25 mg/l) resulted in more than 80% of the plants being male, i.e. having staminate flowers (controls, ca. 30%). Treatment with 6-benzylaminopurine and with indole-3-acetic acid (in either case, 15 mg/l) resulted in all plants being either female (pistillate flowers) or intersexes (bisexual flowers); treatment with abscisic acid (10 mg/l) had a similar but somewhat less pronounced effect.
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  • 52
    ISSN: 1432-2048
    Keywords: Auxin ; Ethylene ; Root formation ; Vigna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rooting responses and ethylene production by hypocotyl cuttings from etiolated mung-bean seedlings treated with the auxins α-naphthaleneacetic acid, γ-(indole-3)-n-butyric acid (IBA) and 2,4,5-trichloro-phenoxypropionic acid were determined. There was no relationship between the abilities of the auxins to induce root formation and their capacities for inducing ethylene production. Studies with mixtures of 3-indoleacetic acid, a poor stimulator of rooting but an effective inducer of ethylene production, and IBA, an effective rooting stimulator but a poor inducer of ethylene production, exposure of cuttings to ethylene or (2-chloroethyl) phosphonic acid (Ethephon), hypobaric storage (150 mb) of treated cuttings, and exposure of auxin-treated cuttings to 7% CO2 also indicated that ethylene is not directly involved in initiation of adventitious roots in this plant material.
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  • 53
    ISSN: 1432-2048
    Keywords: Auxin ; Fusicoccin ; Glucose transport ; Proton flux ; Roots ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Auxin and fusicoccin (FC) stimulate the active uptake of 3-O-methyl glucose (3-O-MG) in those materials in which they have been shown to activate an electrogenic proton extrusion (Pisum sativum L. stems, Zea mays L. coleoptiles and roots). In maize roots the curve relating 3-O-MG influx to external concentrations indicated that the values of the apparent Km increase in the 3-O-MG concentration range between 2×10-5 mol l-1 and 2×10-2 mol l-1. FC did not alter the Km values and its stimulating effect was nearly constant at all 3-O-MG concentrations tested. Basal and FC-induced uptake of 3-O-MG appeared associated with a transient proton influx suggesting that also in maize roots a sugar-proton contransport occurs. Diethyl stilbestrol, which inhibits proton extrusion, inhibited also basal and FC-induced 3-O-MG uptake. The data support the view that the stimulation by FC of 3-O-MG uptake is closely related to that of proton extrusion. The stimulation by FC of 3-O-MG uptake cannot be replaced by increasing extracellular proton concentration, nor may be explained only by the FC-induced hyperpolarization of transmembrane potential difference. The hypothesis is proposed that the effect of FC on 3-O-MG uptake depends on an increase of cytoplasmic pH, following the activation of the proton extruding system.
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  • 54
    ISSN: 1432-2048
    Keywords: Avena ; Immunocytochemistry ; Phytochrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Phytochrome of oat (Avena sativa L., cv. Garry) coleoptile cells in the red-light-absorbing form, Pr, is diffusely distributed while after conversion to the far-red-light-absorbing form, Pfr, it is observed only in very small areas within the cell. Comparison of phytochrome photoversibility measurements to the distribution of the pigment within the cell indicates that the spectral assay is not influenced by the observed compartmentalization of the chromoprotein. However, the observed compartmentalization of phytochrome is correlated with a loss in spectrophotometrically detectable Pr.
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  • 55
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    Planta 141 (1978), S. 179-181 
    ISSN: 1432-2048
    Keywords: Auxin ; Maize ; Root tip ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract [5-3H]Indol-3yl-acetic acid (IAA) applied to the shoot apices of intact 6-day-old maize (Zea mays L.) plants moved into the primary root and accumulated at the root apex. IAA from the shoot could partially satisfy the requirement of the primary root for IAA for growth.
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  • 56
    ISSN: 1432-2048
    Keywords: AMO-1618 ; Antiauxin ; Auxin ; Bromodeoxyuridine ; Cell (fiber) growth ; Gibberellin ; Gossypium ; Ovules (in-vitro culture)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of 5-bromo-2-deoxyuridine (BUdR, thymidine analogue), AMO-1618 (2-isopropyl-4-dimethylamino-5-methylphenyl-1-piperidine carboxylate methyl chloride), a growth retardant, and p-chlorophenoxyisobutyric acid (PCIB, an antiauxin) on growth (dry weight increase) and fiber development in unfertilized cotton (Gossypium hirsutum L.) ovules grown in vitro have been studied. BUdR (5 μM) causes about 70% inhibition of fiber production, with little effect on ovule growth, if applied during the first 6 d of culture in the presence of GA3 and IAA. AMO-1618, when used with GA3 alone, causes only a small reduction in both dry weight and fiber production, but when used with IAA alone reduces both fiber production and dry weight, the effect on the latter being predominant. In the presence of both IAA and GA3, AMO-1618 causes a small decrease in fiber production but a major decrease in dry weight. PCIB completely inhibits fiber growth but has little effect on dry weight, especially when GA3 is present. These results indicate that GA3 mainly promotes ovule growth while IAA is largerly responsible for fiber growth.
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  • 57
    ISSN: 1432-2048
    Keywords: Auxin ; Chlorophyll content ; Chloroplast ; Photosynthetic rate ; Raphanus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dark-grown radish seedlings (Raphanus sativus L.) were sprayed with 10-3 mol·l-1 2,4-dichlorophenoxyacetic acid and then were exposed to a 14:10 light: dark cycle. Cotyledon samples from these seedlings and unsprayed controls were taken for electron microscopy, chlorophyll determinations, and photosynthetic rate measurements at regular intervals for 72 h. A normal development of etioplasts to chloroplasts with formation of typical grana-fret work system was observed in the control cotyledons. The chloroplasts in the 2,4-D-treated cotyledons showed changes in the organization of the grana thylakoids; these thylakoids being more appressed to each other than in the controls. The chlorophyll content of treated plants was less than that of controls but the rate of chlorophyll biosynthesis was unaffected. The photosynthetic rate/mg chlorophyll was considerably higher for treated plants suggesting that 2,4-D treatment resulted in decreased size of the photosynthetic unit.
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  • 58
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    Planta 144 (1978), S. 39-47 
    ISSN: 1432-2048
    Keywords: Aquatic plants ; Auxin ; Cell elongation ; Ethylene ; Ethylene biosynthesis ; Silverions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Elongation of the shoots of three aquatic plants (Hydrocharis morsus-ranae, Regnellidium diphyllum and Ranunculus sceleratus) is stimulated by treatment with ethylene or IAA. The effects of the two hormones are additive, and experiments with an ethylene biosynthesis inhibitor and silver ions indicate that the mechanisms by which ethylene and IAA stimulate growth may be different. Hydrocharis and Ranunculus leaf discs synthesize [14C]ethylene from [14C]methionine, but no [14C]ethylene is formed by Regnellidium, suggesting the existence of an alternative pathway of ethylene biosynthesis in the fern.
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  • 59
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    Planta 136 (1977), S. 173-180 
    ISSN: 1432-2048
    Keywords: Auxin ; Immunoassay ; Nicotiana ; Radioimmunoassay
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    Topics: Biology
    Notes: Abstract We have developed a specific radioimmunoassay [RIA] for indole-3-acetic acid (IAA) in the 0.2 ng to 12 ng range which, in principle, can be extended to other indole auxins as well. Methods are presented for obtaining suitable antibody, for the RIA procedure, and for measuring IAA in methanolic extracts of plant tissues. Antibody specific for IAA was obtained from rabbits immunized with IAA bound to bovine serum albumin by formaldehyde treatment. In assays with this antibody, 2,4-dichlorophenoxyacetic acid and indoles structurally related to IAA reacted from 300- to 3000-fold less than did IAA itself. However, α-and β-naphthaleneacetic acid reacted significantly and hence interfered with the assay. Extracts of tobacco (Nicotiana tabacum L.) tissue were immunoassayed after partial purification by buffer-ether partition. Crown-gall tumor tissue, which is auxin-autotrophic, and pith tissue depleted of auxin by the diffusion method contained, respectively, 26.7 ng and 〈0.5 ng extractable IAA per gram fresh weight.
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  • 60
    ISSN: 1432-2048
    Keywords: Auxin ; Calcium ions ; Cell growth ; Gibberellin ; Membrane permeability ; Membrane potential ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The membrane potential difference of dwarf maize coleoptile cells is increased by both 10-5moll-1 gibberellic acid (GA3) and indoleacetic acid (IAA) a few minutes after application. A final level is reached after 10–20 min. The membrane permeability ratio P Na:P K is altered by both hormones during the first 15 min after application, indicating a rapid effect on the membrane. Elongation growth of coleoptile segments, however, is only stimulated by IAA. The auxin-induced growth as well as the auxin effect on membrane permeability depends on the calcium ion concentration of the medium. It is concluded that IAA acts via a proton extrusion pump that is electrically balanced by a potassium ion uptake, driven by the electromotive force of the pump. The mode of action of GA3 on elongation growth is assumed to involve a process that depends on the physiologic state of the tissue and/or metabolic energy.
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  • 61
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    Planta 140 (1978), S. 31-35 
    ISSN: 1432-2048
    Keywords: Auxin ; Coleoptiles ; Electrical Potential ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Following asymmetric application of indoleacetic acid to maize (Zea mays L.) coleoptiles the early time course of changes in lateral electrical potential was externally monitored with static-drop electrodes. First, an early negative potential change of ca.-1 mV was measured at the surface on the side of a strong auxin application. This negative auxin effect ended after ca. 15 min and was followed by a strong and lasting auxin stimulation of a positive lateral potential up to +12 mV at the auxin-treated side. The initial auxin effect appeared to depend on the size of the step-up in auxin concentration.
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  • 62
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    Planta 140 (1978), S. 137-142 
    ISSN: 1432-2048
    Keywords: Auxin ; Cell elongation ; Proton secretion ; Triticum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth of Triticum aestivum L. cv. Cappelle Desprez coleoptiles is promoted by 5.7×10−5 M indole acetic acid (IAA) as effectively in pH 3.4 buffer as in water, but IAA is not effective in the presence of buffer at pH 3.0 or 3.2 A combination of 5.7×10−5 M IAA and pH 3.4 buffer promotes growth to a greater extent than pH 3.2 buffer alone, which is optimal for acid-induced growth. IAA employed at 10−7 M is still effective at promoting growth in the presence of pH 3.4 buffer, moreover, IAA at 10−7 M interacts synergistically with the acidic buffer to promote growth. It is concluded that IAA and acid promote growth via separate mechanisms, and that IAA does not promote cell wall loosening by rendering the cell wall more acid.
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  • 63
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    Planta 144 (1978), S. 79-84 
    ISSN: 1432-2048
    Keywords: Auxin ; Cell elongation ; Lead ; Triticum
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    Topics: Biology
    Notes: Abstract In vitro studies of IAA-induced cell elongation in Triticum aestivum have demonstrated that lead causes a large reduction in elongation. Inhibition of elongation can be reduced by increasing the concentration of IAA, or by the addition of calcium. The inhibitory effect appears to be linked with changes in the properties of the cell walls. Experiments are described which show that lead becomes bound strongly to certain chemical substances involved in cell wall architecture.
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  • 64
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    Planta 142 (1978), S. 207-210 
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Auxin ; Cytokinin ; Flowers (sex) ; Gibberellin ; Sex expression ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When 7-d-old plantlets of spinach (Spinacia oleracea L.) were immersed with their roots for 24 h in 25 mg/l gibberellic acid (GA3), or 15 mg/l 6-benzylaminopurine (6-BAP), or 15 mg/l indole-3-acetic acid (IAA), or 10 mg/l abscisic acid (ABA) and subsequently grown on long (18-h) days, the ratio of plants with male and female flowers, which in the controls was almost 1:1 (48 and 52%, respectively), was greatly altered. The treatments with 6-BAP, IAA and ABA raised the percentage of female plants to 88, 76 and 71%, respectively; the GA3 treatment increased the percent of male plants to 79%. When young, vegetative spinach plants (3 visible leaves) grown in 18-h days were cut a the root neck, and the shoots grown with their bases in nutrient solution, with adventitious roots either being allowed to develop or being systematically removed, 85% of the plants without roots became males, 85% of those with roots became females. But if the cut shoots were first, for 28 h, placed in a 15-mg/l 6-BAP solution and then grown in the absence of roots, the percent of female plants was restored to 84. These results fully agree with those obtained previously with hemp, namely, that plant growth regulators exert a regulating effect on the sex expression of dioecious plants when applied through the roots in early stages of development; that the root system plays an important role in determining the sex of these plants, that this role of the roots is associated with the synthesis of cytokinins in them. Dioecious short- and long-day plants do not differ in these respects.
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  • 65
    ISSN: 1432-2048
    Keywords: Auxin ; Benzoxazolinones ; Receptors ; Supernatant factor ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A naturally-occurring material termed ‘supernatant factor’ [Ray, P.R., Dohrmann, U., Hertel, R.: Plant Physiol. 59. 357–364 (1977)], which has the property of modifying the binding affinity of auxins to receptor sites, has been isolated from corn (Zea mays L.) and characterised as a mixture of 6-methoxy-2-benzoxazolinone (MBOA) and 6,7-dimethoxy-2-benzoxazolinone (DMBOA). DMBOA is about 50 times more active than MBOA in inhibiting binding of the auxin 1-naphthylacetic acid to membrane-bound or solubilised receptors. The activity of these compounds and the parent analogue in inhibiting auxin binding is correlated with their ability to inhibit auxin-induced growth.
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  • 66
    ISSN: 1432-2048
    Keywords: Auxin ; Compartmental analysis ; Ion fluxes ; Petroselinum ; Suspension culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transport of 86Rb+/K+, 22Na+, 36Cl−, and [3H]indole acetic acid (IAA) has been studied on suspension-cultured cells of the parsley, Petroselinum crispum (Mill) Nym. By compartmental analysis two intracellular compartments of K+, Na+, and Cl− have been identified and ascribed to the cytoplasm and vacuole; half-times of exchange were around 200 s and 5 h, respectively. According to the Ussing-Teorell flux equation, active transport is required for the influx into the cytoplasm at the plasmalemma (K+, Cl−) and the tonoplast (K+, Na+, Cl−). The plasmalemma permeability pattern, PK:PNa:PCl=1.00:0.24:0.38, features an increased chloride permeability compared with cells from higher plant tissues. IAA uptake showed an exponential timecourse, was half-maximal after 10 min, and a linear function of the IAA concentration from 10−9 to 10−5 M. IAA and 2,4-dichlorophenoxy acetic acid reduce the apparent influx of K+, Na+, Cl− during the initial 30 min after addition and subsequently accelerate both in- and efflux of these ions. We discuss that auxins could affect the ion fluxes in a complex way, e.g. by protonophorous activity and by control of the hypothetical proton pump.
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  • 67
    ISSN: 1432-2048
    Keywords: Auxin ; Cytokinin ; 5-Fluorouracil ; Helianthus ; Ribosome synthesis and activity ; Tuber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In order to examine the relation of protein synthesis to the onset of growth, changes in ribosome content and activity were compared in aged, metabolically active Jerusalem artichoke (Helianthus tuberosus L.) slices incubated in water or 2,4-dichlorophenoxyacetic acid+kinetin. In water, cells do not grow or divide and rRNA and protein levels remain constant. The percentage membrane-bound (mb) ribosomes drops from 25% to 16% during 24h. At the same time the proportion of ribosomes active in protein synthesis in both free and mb populations declines from about 69% to 54%. In auxin+kinetin, cell expansion occurs and is accompanied by a 3-fold increase in rRNA and a 50% increase in total protein content. The percentage mb ribosomes remains at 25% throughout 48 h of growth. During the first 24h of growth 70% of ribosomes in both free and mb populations are active; this value declines to near water levels at 48 h. Considering the large increase in total ribosomes the number of synthetically active ribosomes is substantially increased during growth. 5-Fluorouracil (5-FU) does not inhibit hormone induced growth but does depress total rRNA content by about one-third. It also reduces [3H]uridine incorporation into ribosomes by 70% and the newly made ribosomes are mostly inactive in protein synthesis. On the other hand, the inhibitor does not significantly affect the proportion of total ribosomes active in protein synthesis and only partially reduces protein accumulation during the second 24 h of growth. It is suggested that while ribosome production is reduced in 5-FU, ribosome turnover is also retarded resulting in retention of near normal capacity for protein synthesis and growth.
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  • 68
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    Planta 135 (1977), S. 289-295 
    ISSN: 1432-2048
    Keywords: Antiauxin ; Auxin ; Meristem differentiation ; Riella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During the development of the unistratose gemmae of Riella helicophylla, the single intercalary meristem of the very young gemmae is subdivided into two lateral meristems. The duration of the cell reproduction cycle increases from the margin to the median part of the gemmae. This polarization within the meristem disappears after addition of the antiauxin PCIB to the culture medium. PCIB leads to a retardation or blockage of the cell cycle during the light period of the culture. Under the influence of PCIB the amount of starch in the chloroplasts is strikingly increased, probably because of a reduction of starch degradation. Addition of sugars compensates the effect of PCIB on the cell cycle. The effects of PCIB are counteracted by auxin. The results are taken as evidence that auxin plays a role in directing the transport of substances needed for the continuation of the cell reproduction cycle between adjacent cells of the meristem.
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  • 69
    ISSN: 1432-2048
    Keywords: Auxin ; Cambium ; Gibberellin ; Picea ; Tracheids-wood production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diameter and wall thickness of tracheids produced after indoleacetic acid treatment were not significantly different from those of the intact controls, for the first few weeks after treatment of disbudded shoots of Picea abies Karst. and Picea sitchensis (Bong.) Carr. However, lateral application of indoleacetic acid (IAA) to intact shoots increased both tracheid diameter and wall thickness; it is suggested that IAA acted synergistically with another endogenous growth regulator, which was also removed by disbudding. Increase in wall thickness after exogenous IAA was associated with increase in duration of the wall thickening phase of tracheid differentiation; this is discussed in relation to the seasonal change from early to latewood. Cambial dormancy was induced by disbudding during active wood production. Since this occurred with or without the presence of current leaves, it is concluded that in Picea continued cambial activity depends upon supply of auxin from the buds, and cannot be supplied from expanded leaves or from the internode itself. Neither indoleacetic acid nor gibberellic acid stimulated renewed cambial activity when applied after the cessation of wood production. With both disbudded and intact shoots, the effectiveness of exogenous IAA declined with time, probably due to decreasing penetration through callus developing at the wounded surface. It is suggested that this apparent change in IAA effectiveness may explain some discrepancies between the results of previous observers.
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  • 70
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    Planta 134 (1977), S. 295-299 
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Apical dominance ; Auxin ; Gibberellin ; Hormone transport ; Phaseolus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Abscisic acid (ABA) in lanolin, applied to the internode of decapitated runner bean plants enhances the outgrowth of lateral buds. The optimum concentration of the paste is 10-5 M. The effect of ABA is counteracted by indoleacetic acid (IAA) but not by gibberellic acid (GA3). There is no effect when ABA is applied to the apical bud or lateral buds of intact plants. However, 13.2 ng given to the lateral buds of decapitated plants stimulate their growth, whereas higher concentrations are inhibitory. Consequently, ABA enhances growth of lateral buds directly, but only when apical dominance is already weakened. The growth of the decapitated 2nd internode was not affected by ABA. Radioactivity from [2-14C] ABA, applied to nonelongating 2nd internode stumps of decapitated runner bean plants moves to the lateral buds, whereas [1-14C]IAA-and [3H]GA1-translocation is much weaker. ABA transport is inhibited if IAA or [3H]GA1 is applied simultaneously. In elongating internodes [14C]ABA is almost completely immobile. [14C]IAA-and [3H]GA1-translocation is not affected by ABA. The amount of radioactivity from labelled ABA, translocated to the lateral buds, is highest during the early stages of bud outgrowth.
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  • 71
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    Planta 135 (1977), S. 207-212 
    ISSN: 1432-2048
    Keywords: Auxin ; Cytokinin ; Explants ; Helianthus ; Tuber (explants) ; Xylem differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract the culture of Jerusalem artichoke (Helianthus tuberosus L.) tuber explants on filter paper discs moistened with liquid medium resulted in rapid and consistent xylem differentiation. The number of tracheary elements increased in discrete steps, the first at 48 h with a second at 56–58 h, following partially synchronous mitoses at 20 and 30 h. Factors favouring xylem cell differentiation were optimum levels of both an auxin and a cytokinin, low medium nitrogen concentrations, small volumes of medium, and high culture temperatures. A cell counting method employing Feulgen-stained nuclei and suitable for quantifyings small numbers of immature tracheary elements is described.
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  • 72
    ISSN: 1432-2048
    Keywords: Auxin ; Avena ; Cell elongation ; Ion uptake ; Malate synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The short-term effects of auxin (indole-3-acetic acid) and fusicoccin (FC) on Rb+ uptake and malate accumulation in Avena sativa L. coleoptile sections have been investigated. FC stimulates 86Rb+ uptake within 1 min while auxin-enhanced uptake begins after a 15–20-min lag period. Auxin has little or no effect on 86Rb+ uptake at external pHs of 6.0 or less, but substantial auxin effects can be observed in the range of pH 6.5 to 7.5. Competition studies indicate that the uptake mechanism is specific for Rb+ and K+. After 3 h of auxin treatment the total amount of malate in the coleoptile sections is doubled compared to control sections. FC causes a doubling of malate levels within 60 min of treatment. Auxin-induced malate accumulation exhibits a sensitivity to inhibitors and pH which is similar to that observed for the H+-extrusion and Rb+-uptake responses. Both auxin- and FC-enhanced malate accumulation are stimulated by monovalent cations but this effect is not specific for K+.
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  • 73
    ISSN: 1432-2048
    Keywords: Abscisic acid ; Auxin ; Cambium ; Picea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Indole-3-acetic acid (IAA) and abscisic acid (ABA) were identified by combined gas chromatography-mass spectrometry (GCMS) in fractions obtained by diffusion and extraction from bark peelings of Sitka spruce. A procedure is described for the quantitative analysis of IAA and ABA levels in the same extract using the GCMS technique of single-ion current monitoring. This procedure was used to measure the diffusible, free, and bound fractions of IAA and ABA in the cambial region of Sitka spruce throughout one year; the range in concentration for these fractions was 0.06–0.30, 0.46–3.85, and 0.04–0.20 μg/g oven-dry weight, respectively, for IAA, and 0–0.08, 0.03–2.21, and 0.13–0.66 μg/g oven-dry weight, respectively, for ABA. Movement in the cambial region was found to be polar for endogenous IAA and nonpolar for endogenous ABA. Recoveries of [14C]IAA internal standards showed that 73–99.5% of the IAA was lost during purification, and that there could be up to 5-fold differences in recovery between purifications, indicating that IAA loss shold be measured in quantitative analyses.
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  • 74
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    Planta 135 (1977), S. 1-5 
    ISSN: 1432-2048
    Keywords: Auxin ; Cell elongation ; Elongation ; Root growth ; Zea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of indole-3-acetic acid (IAA) on the elongation rates of 2 mm corn (Zea mays L.) root segments induced by citrate-phosphate buffer (or unbuffered) solutions of pH 4.0 and 7.0 was studied. At pH 7.0, auxin initially reduced the elongation rate in both buffered and unbuffered solutions. Only in buffer at pH 7.0 was auxin at a concentration of 0.1 μM found to promote the elongation rate though briefly. THis promoted rate represented only ca. 20% of the rate achieved with only buffer at pH 4.0. Auxin in pH 4.0 buffered and unbuffered solutions only served to reduce the elongation rates of root segments. Some comparative experiments were done using 2 mm corn coleoptile segments. Auxin (pH 6.8) promoted the elongation rate of coleoptile segments to a level equal or greater than the maximal H ion-induced rate. The two responses of root segments to auxin are compared to auxin action in coleoptile growth.
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  • 75
    ISSN: 1432-0878
    Keywords: Pituitary ; Dexamethasone ; ACTH ; Autoradiography ; Immunocytochemistry
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    Topics: Biology , Medicine
    Notes: Summary 3H-Dexamethasone (10 μg/kg) was injected intravenously in adrenalectomized rats and after survival times of 5, 30, 60, and 180 min its uptake within the pituitary was studied by autoradiography. Radioactivity was concentrated in cell nuclei in the pars nervosa and pars distalis. Within the pars intermedia, only cells of the marginal zone were labeled. In the pars distalis, some cells showed a weak nuclear accumulation of radioactivity as early as 5 min after injection. The tissue radioactivity was nearly maximal at 5 min, and the proportion of radioactivity in nuclei reached a maximum of 60–70% by 30 min. In competition experiments, non-radioactive steroids (1 mg/kg) were injected 5 min before 3H-dexamethasone and sacrifice was 30 min later. Dexamethasone markedly diminished the nuclear accumulation in the pars distalis, but corticosterone and progesterone did not. In the pars nervosa, corticosterone and progesterone competed for nuclear uptake of 3H-dexamethasone, although less effectively than dexamethasone itself. Different cell types in the pars distalis were characterized by treating autoradiograms with an immuno-peroxidase bridge procedure. Cells treated with anti-ACTH 17–39 had the greatest nuclear concentration of radioactivity, and those stained with anti-TSH were least heavily labeled. Cells treated with antisera to GH, PRL, and hCG were moderately labeled.
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    Cell & tissue research 178 (1977), S. 17-38 
    ISSN: 1432-0878
    Keywords: Myosin ; Immunocytochemistry ; Adrenal medulla ; Exocytosis ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myosin was isolated in high purity from the bovine adrenal medulla by gel filtration and ion exchange chromatography. The purified myosin was analyzed by electrophoresis in gels containing SDS and found to contain a 200,000 molecular weight heavy chain and major light chains of molecular weights 20,000 and 17,000 in a 1∶1∶1 molar ratio. At high ionic strength the myosin had high Ca-ATPase and K-EDTA-ATPase activities and low Mg-ATPase activity. At low ionic strength, the Mg-ATPase was activated to a low level by rabbit muscle actin. The myosin was found to decorate F-actin in the absence, but not the presence of ATP. In low ionic strength solutions, the myosin assembled into characteristic bipolar filaments. The distribution of this myosin in the adrenal medulla and of cross-reacting myosin in several other bovine tissues was determined with the use of antimedullary myosin immunoglobulin G as a specific stain that was detected by direct and indirect immunofluorescence. In the medulla strong staining was seen between the chords of chromaffin cells indicating the presence of a highly muscular vasculature that may perform functions analogous to those of the myoepithelium of exocrine glands. The chromaffin cells showed weak positive staining around the nuclei and in a pattern radiating toward adjacent blood vessels. Cells of the inner zone of the adrenal cortex showed strong staining in the peripheral cytoplasm while cells in the intermediate and outer zones did not stain. In a blood smear, platelets and the cytoplasm of leukocytes stained strongly while erythrocytes did not stain. In striated muscle and the gray and white matter of the cerebrum only the capillaries and larger vessels stained. In the liver the phagocytic cells bordering vascular sinuses stained strongly while the hepatocytes were separated from one another by a 2 micron trilaminar band possibly representing the microfilament web surrounding the bile canaliculi and associated with junctional complexes. The results suggest that myosin is present in several highly differentiated, non-motile tissue cells where it may play a role in secretion or other specialized functions.
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    Fresenius' Zeitschrift für analytische Chemie 292 (1978), S. 381-384 
    ISSN: 1618-2650
    Keywords: Best. von Aminen, aromat. ; Chromatographie, Dünnschicht ; Remissionsmessung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird eine Methode zur quantitativen Bestimmung von aromatischen Aminen beschrieben. Diese werden dünnschicht-chromatographisch auf Kieselgel 60 F254 Fertigplatten in den Laufmitteln n-Propanol/Methanol/Wasser/Eisessig (65∶15∶15∶20; Vol.) oder n-Butanol/Wasser/Eisessig (66∶17∶17; Vol.) von den Begleitstoffen abgetrennt. Die getrennten Aminflecke werden entweder im Ultraviolett-Bereich oder nach Diazotierung im sichtbaren Bereich mit dem Chromatogramm-Spektralphotometer PMQ II nach der Remissionsmethode gemessen und anhand der auf derselben Platte aufgestellten Eichgerade ausgewertet. Die quantitative Bestimmung wird anhand der beiden Amine 5-Amino-2,4,6-trijod-isophthalsäurebis-(2,3-dihydroxy-propyl-N-methylamid) (I) und 2,4,6-Trijod-3-aminobenzoesäure (II) in Röntgenkontrastmittelpräparaten (RKP) demonstriert. Sowohl im UV- als auch im sichtbaren Bereich, läßt sich in 3000 μg RK-Säure (RKS) noch 0,1 μg freies aromatisches Amin, das sind 0,003%, bezogen auf die eingesetzte Menge RKS, mit einer maximalen relativen Standardabweichung von 4% bestimmen. Diese Methode ist spezifischer und empfindlicher als die der Diazotierung in Lösung.
    Notes: Summary The aromatic amines are separated from impurities by thin-layer chromatography on silica gel 60 F254 precoated plates in the mobile solvents n-propanol/methanol/water/glacial acetic acid (65∶15∶15∶20; vol.) or n-butanol/water/glacial acetic acid (66∶17∶17; vol.). The separated amine spots are measured by the remission method by means of the TLC densitometer PMQ II, either in the u.v. region or, after diazotization, in the visible region, and evaluated on the basis of the linear calibration curve set up on the same plate. Quantitative determination is demonstrated by means of the two amines, 5-amino-2,4,6-triiodoisophthalic acid-bis-(2,3-dihydroxypropyl-N-methylamide) (I) and 2,4,6-triiodo-3-aminobenzoic acid (II), in radiopaque contrast media (RCM). Both in the u.v. and visible regions, it is still possible to determine 0.1 μg of free aromatic amine in 3000 μg of radiopaque contrast medium acid (RCA), or 0.003% in terms of the amount of RCA used, with a maximum relative standard deviation of 4%. This method is more specific and more sensitive than that of diazotization in solution.
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    Fresenius' Zeitschrift für analytische Chemie 293 (1978), S. 135-137 
    ISSN: 1618-2650
    Keywords: Analyse von Desodorantien, Phenolderivaten in Kosmetika ; Chromatographie, Dünnschicht
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Phenolische Desodorantien in kosmetischen Präparaten lassen sich durch Umsetzung mit Echtrotsalz Al (Anthrachinondiazonium-chlorid-1) in wäßrig-alkalischer Lösung, Extraktion des gebildeten Azofarbstoffes mit einem organischen Lösungsmittel und anschließender Dünnschicht-Chromatographie schnell identifizieren. In den meisten Fällen ist die Abhängigkeit zwischen der Extinktion der Farbstofflösung und der eingesetzten Menge des betreffenden Desodorants linear, wodurch dann auch quantitative Bestimmungen möglich sind.
    Notes: Summary Phenolic compounds, used as deodorants in cosmetic products can be identified quickly by reaction with anthraquinonediazonium chloride-1 (Echtrotsalz Al) in aqueous alkaline medium, extraction of the azo dye with an organic solvent and separation by thinlayer chromatography. The relation between the absorbance of the coloured solution and the concentration of the deodorant concerned is generally linear; in these cases quantitative determinations are always possible.
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    Fresenius' Zeitschrift für analytische Chemie 291 (1978), S. 366-368 
    ISSN: 1618-2650
    Keywords: Nachw. von N-Heterocycl. Verbindungen ; Chromatographie, Dünnschicht ; CuSO4-imprägnierte Schichten, Fluorescenz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Durch die charakteristischen Fluorescenzfarben und die Fluorescenz-Thermochromie der CuJ-Komplexe lassen sich N-Heterocyclen auf Chromatogrammen meist einwandfrei identifizieren. Eine wesentliche Vereinfachung wird durch die Verwendung CuSO4-imprägnierter Kieselgelschichten erreicht. Die Nachweisempfindlichkeiten insbesondere bei tiefer Temperatur ändern sich im Vergleich zur ursprünglichen Technik kaum.
    Notes: Summary N-Heterocycles can usually be identified with certainty through the characteristic fluorescence colours and fluorescence-thermochromism of the CuI-complexes. The use of CuSO4-impregnated silica gel layers facilitates the procedure considerably, and scarcely reduces the sensitivity of detection, particularly at low temperature.
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    Fresenius' Zeitschrift für analytische Chemie 292 (1978), S. 415-416 
    ISSN: 1618-2650
    Keywords: Trenn. von Anorgan. Ionen ; Chromatographie, Dünnschicht ; mit p-Toluidin imprägnierte Schichten
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    Cell & tissue research 186 (1978), S. 399-412 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Dog ; Pars distalis ; Thyrotropin (TSH) ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the immunoperoxidase technique and antisera to the specific beta (β) subunits of bovine and rat TSH1, selective immunocytochemical staining was localized in a specific cell population in the pars distalis of the dog pituitary gland. These TSH cells were found to be positive to aldehyde fuchsin, alcian blue, periodic acid-Schiff (PAS) and aniline blue. With the performic acidalcian blue (pH 0.2) -PAS-orange G procedure these cells stained blue-purple, demonstrating FSH/LH cells (blue or turquoise), ACTH/MSH cells (redpurple) and PRL cells (orange-red). The TSH cells were further differentiated from other functional cell types of the pars distalis on the basis of their typical cytological features, intraglandular distribution and by immunocytochemical double staining. In the pars distalis of adult male dogs the TSH cells were mostly shown to be smaller in size and less numerous than in bitches in the anestrous phase of the sexual cycle. Moreover, cytological alterations in the immunoreactive thyrotrophs in the pituitary of male and female dogs generally paralleled the spontaneous changes in thyroid function associated with thyroid atrophy and/or pituitary insufficiency, and thyroid hyperplasia or goiter. In conclusion, because of their specificity and high potency, the antisera to the β-subunits of bovine and rat TSH represent an effective tool for the selective immunocytochemical localization of TSH in the dog pituitary. This allows the study of the morphology and function of TSH cells under different physiological, pathological and experimental conditions.
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    Cell & tissue research 188 (1978), S. 99-106 
    ISSN: 1432-0878
    Keywords: LHRH-neurosecretion ; Avian hypothalamus ; Vasotocin neurosecretion ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A fluorescent technique applying specific LHRH and vasotocin antisera was used for the immunocytochemical localization of the respective neurosecretory systems in the hypothalamus of gonadectomized, testosteronetreated and/or serotonin injected male domestic ducks. An immunoreactive (IR) LHRH-producing system, with perikarya located in the preoptic nucleus, could be traced through the ventral hypothalamus down to the external layer of the rostral and caudal ME, in close vicinity to the hypophysial portal system. An IR-vasotocin system originating in the paraventricular and supraoptic nuclei ran through the ventral hypothalamus, but terminated in (i) the external layer of the rostral ME, and (ii) in the posterior lobe of the hypophysis.
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    Cell & tissue research 188 (1978), S. 119-132 
    ISSN: 1432-0878
    Keywords: Neurophysin ; Paraventricular nucleus ; Supraoptic nucleus ; Sheep ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antiserum cross-reactive against ovine neurophysins-I-II and -III has been used in conjunction with the immunoperoxidase histochemical procedure to localize the cells of the sheep paraventricular (PVN) and supraoptic nuclei (SON). In order to describe the topographical distribution of the SON and PVN a study was made on the serial sections cut (a) transversely from rostral to caudal positions and (b) sagittally from lateral to medial positions of the hypothalamus. The cells of the SON, when examined in the transverse aspect, extended approximately 1900 μ caudally and when examined in the sagittal plane were contained within a lateral-medial distance of 4830 μ. In each case the SON cells lay adjacent to the optic chiasm. As sections were cut transversely, the cells of the PVN first appeared in a rostral position defined as 0 μ and close to the ventral lining of the third ventricle. This general ventral and ventro-lateral distribution of cells maintained up to a caudal distance of approximately 840 μ. From positions 1260–2310 μ there was a dramatic dorsal shift of the PVN cells which by this time had also extended laterally. The total rostral-caudal distance occupied by the PVN cells was 3150 μ. That the lateral-medial distance occupied by the PVN was small (1050 μ) was determined on examining the magnocellular nuclei in sagittal section.
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    Cell & tissue research 188 (1978), S. 259-264 
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Human fetus ; Oxytocin ; Neurophysin ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The use of antibodies against oxytocin or neurophysin enabled the detection by immunocytochemistry of oxytocin-neurophysin neurons in the hypothalamus in the human fetus. The perikarya of these neurons are located in the paraventricular and supraoptic nuclei. Immunoreactive neurons occur in the median eminence. The neurophysin immunoreactive neurons were more numerous than the oxytocin immunoreactive neurons. The specificity of the immunocytological reaction was controlled. The first oxytocin-neurophysin neurons are seen as early as the 14th week of gestation.
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  • 85
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    Cell & tissue research 185 (1977), S. 465-479 
    ISSN: 1432-0878
    Keywords: Somatostatin cells ; Pancreas ; Gut ; Immunocytochemistry ; Comparative study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Somatostatin cells are numerous in the pancreas and digestive tract of mammals as well as birds. In the pancreas of chicken, cat and dog they occur in both the exocrine parenchyma and in the islets. In the rat and rabbit, somatostatin cells have a peripheral location in the islets, whereas in the cat, dog and man the cells are usually more randomly distributed. In the stomach of rabbits and pigs, somatostatin cells are more numerous in the oxyntic gland area than in the pyloric gland area, whereas the reverse is true for the cat, dog and man. In the cat, pig and man, somatostatin cells are fairly numerous in the duodenum, whereas in the rat, rabbit and dog they are few in this location. In the remainder of the intestines somatostatin cells are few but regularly observed. Somatostatin cells are numerous in the human fetal pancreas and gut. In the fetal rat, somatostatin cells first appear in the pancreas and duodenum (at about the 16–17th day of gestation) and subsequently in the remainder of the intestine. Somatostatin cells do not appear in the gastric mucosa until after birth. Three weeks after birth, somatostatin cells show the adult frequency of occurrence and pattern of distribution. In the chicken, somatostatin cells are numerous in the proventriculus, absent from the gizzard, abundant in the gizzard-duodenal junction (antrum), infrequent in the duodenum and virtually absent from the remainder of the intestines. No immunoreactive cells can be observed in the thyroid of any species nor in the ultimobranchial gland of the chicken. In the chick embryo, somatostatin cells are first detected in the pancreas and proventriculus (at about the 12th day of incubation). They appear in the remainder of the gut much later, in the duodenum at the 16th day, in the antrum at about the 19th day and still later in the lower small intestine. The ultrastructure of the somatostatin cells was studied in the chicken, rat, cat and man; the cells were identified by the consecutive semithin/ultrathin section technique. The somatostatin cells display the properties of the D cell. There was no difference in granule ultrastructure between somatostatin cells in the gut and the pancreas. The granules, which are the storage site of the peptide, are round, supplied with a tightly fitting membrane and have a moderately electron-dense, fine-granulated core. The mean diameter of the somatostatin granules is smallest in rat (155–170 nm) and largest in the chicken (270–290 nm).
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    Medical & biological engineering & computing 15 (1977), S. 72-74 
    ISSN: 1741-0444
    Keywords: Bone ; Elasticity ; Mechanical strength
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The mechanical properties of canine long bones have been determined. The mean and standard deviation of the maximum load supported by six fresh canine femurs in 3-point bending was 1366±253 N. In all cases, the bones sustained a considerable amount of plastic deformation before failure. The modulus of elasticity (GN/m2), ultimate tensile stress (MN/m2) and yield stress (MN/m2) were 13·86, 108·3 and 88·3 for six humeral specimens and 13·88, 142·1 and 104·0 for 13 tibial specimens, respectively. The tibial specimens showed a statistically significant higher ultimate strength than the humeral specimens.
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    Medical & biological engineering & computing 15 (1977), S. 207-208 
    ISSN: 1741-0444
    Keywords: Bone ; Instrumentation ; Tensile strength
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    Topics: Biology , Chemistry and Pharmacology , Medicine
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    Cell & tissue research 186 (1978), S. 551-558 
    ISSN: 1432-0878
    Keywords: C-cells ; Thyroid gland ; Immunocytochemistry ; Calcitonin antibody ; Mammals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the thyroid glands of the horse, pig, deer, mole, and rat, C-cells could be demonstrated by means of the immunocytochemical PAP-technique using rabbit antisera against human calcitonin. Only in ruminants, the crossreaction between the intracellularly stored antigen and the antibodies used appeared to be incomplete.
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    Cell & tissue research 177 (1977), S. 317-323 
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Lamprey ; Vasotocinergic system ; Adenohypophysis ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary With the use of the unlabeled antibody peroxidase-antiperoxidase (PAP) technique at the light microscopic level, it was shown that the preoptico-hypophysial neurosecretory system of the adult migrating Lampetra fluviatilis is a vasotocinergic system. It does not synthesize vasopressin. The results are entirely consistent with earlier chromatographic and pharmacological indications that it produces little or no oxytocin-like peptide hormone. In the adenohypophysis, immunoreactive neurohypophysial peptidergic fibres are absent.
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  • 90
    ISSN: 1432-0878
    Keywords: Pars intermedia of hypophysis ; Rana temporaria ; Mesotocinergic and vasotocinergic fibres ; Immunocytochemistry ; Electron microscopy
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    Notes: Summary With the use of the unlabeled antibody peroxidase-antiperoxidase (PAP) method at the electron microscopic level, it has been shown that the pars intermedia of the hypophysis of Rana temporaria contains a diffuse intercellular network of separate mesotocinergic and vasotocinergic nerve fibres.
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    Cell & tissue research 179 (1977), S. 211-224 
    ISSN: 1432-0878
    Keywords: Somatostatin (rat) ; Hypothalamus ; Fibers and perikarya ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the immunoenzyme bridge-technique at the light and electron microscopic levels, somatostatin can be demonstrated in the perikarya of the anterior periventricular nucleus, in the median eminence and in the parvocellular hypothalamic nuclei of the rat. In the latter regions the perikarya are negative, whereas a positive reaction for somatostatin is found in a delicate network of fibers and middle-sized granules of very small axons. In light of these results, the double function of somatostatin — as release inhibiting hormone and as transmitter — is discussed. The positive staining reaction in the organum vasculosum laminae terminalis of male and female rats as well as in the subfornical organ, the nucleus dorsalis thalami and the nucleus medialis habenulae in female controls and pregnant rats is not due to somatostatin-containing structures, but partly to substance P and partly to a substance which could not be defined.
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  • 92
    ISSN: 1432-0878
    Keywords: External region of median eminence (Rat) ; Vasopressinergic and oxytocinergic fibres ; Hypothalamic lesions ; Adrenalectomy ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The origin of the vasopressinergic and oxytocinergic nerve fibres of the external region of the rat median eminence was investigated by means of hypothalamic lesions, adrenalectomy and immunocytochemistry. The results obtained in bilaterally adrenalectomized animals with complete, or incomplete, destruction of the suprachiasmatic nuclei showed that, at least, the great majority of the vasopressinergic and oxytocinergic nerve fibres of the external region of the rat median eminence do not originate from the suprachiasmatic nuclei. From the observations obtained in bilaterally adrenalectomized animals with total or subtotal destruction of both paraventricular hypothalamic nuclei, it appears that the paraventricular nuclei must be the origin of (nearly) all the vasopressinergic and oxytocinergic nerve fibres of the external region of the rat median eminence. The results strongly suggest that both types of fibres originate from all parts of the paraventricular nuclei.
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    Cell & tissue research 180 (1977), S. 491-503 
    ISSN: 1432-0878
    Keywords: Pig ; Oxytocin ; [8-Lysine]-Vasopressin ; Specific localization ; Immunocytochemistry ; One hormone, One Neurophysin
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary Synthetic oxytocin and [8-arginine]-vasopressin conjugated to bovine thyroglobulin were used to induce specific antibodies in rabbits. The specificity of the anti-oxytocin serum, and the suitability of the anti-[8arginine]-vasopressin serum for the detection of [8-lysine]-vasopressin, was evaluated by immunofluorescent studies of the respective hormones bound to Sepharose 4B particles. Oxytocin and [8-lysine]-vasopressin were specifically localized in the paraventricular (PVN) and supraoptic (SON) nuclei of the pig hypothalamus using the immunoperoxidase staining technique. After an examination of serial transverse and sagittal sections stained for either of the hormones we observed that: 1. In the rostral SON, oxytocin and vasopressin containing neurons were uniformly distributed; 2. In the caudal SON, most of the neurons contained oxytocin, but there were still a few ‘vasopressin’ neurons; 3. In the rostral PVN, the two hormones were evenly spread in neurons close to the third ventricle; 4. In the caudal PVN, the oxytocin and vasopressin containing neurons were differentially distributed, with ‘oxytocin’ neurons adjacent to the third ventricle, and ‘vasopressin’ neurons lateral to these and concentrated in the dorso-caudal PVN. In the cells of the PVN, there was evidence that the distribution of oxytocin and vasopressin is similar to the distribution of porcine neurophysin-II and porcine neurophysin-I respectively. This similarity is consistent with the one hormone — one neurophysin concept in the pig.
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    Cell & tissue research 184 (1977), S. 15-27 
    ISSN: 1432-0878
    Keywords: Human hypothalamus ; Magnocellular neurosecretory nuclei ; Suprachiasmatic nuclei ; Vasopressinergic and oxytocinergic neurons ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Summary The human hypothalamic-neurohypophysial hormone-producing nuclei were investigated with the unlabeled antibody peroxidase-antiperoxidase complex (PAP) technique at the light microscopic level. The size, shape and location of the supraoptic, paraventricular, accesssory supraoptic and suprachiasmatic nuclei were determined. It was demonstrated in the human hypothalamus, as well as in the hypothalamus of other mammals, that vasopressin and oxytocin are synthesized in separate neurons. In each of the nuclei of the magnocellular neurosecretory system, the distribution, ratios and structural features of the vasopressinergic and oxytocinergic neurons were determined. It was shown that the human suprachiasmatic nuclei contain numerous neurophysin-vasopressin-producing neurons.
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  • 95
    ISSN: 1432-0878
    Keywords: Endocrine cells ; Gut ; Neurotensin ; Immunocytochemistry ; Comparative studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Endocrine cells displaying neurotensin immunoreactivity are found scattered in the jejuno-ileum of all mammals studied, including man. They are rather scarce in rat, guinea pig, rabbit and pig and fairly numerous in cat, dog and man. In most mammals the neurotensin cells predominate on the villi. Only in the dog are they more numerous in the crypts. In the chicken, neurotensin cells occur all along the intestinal tract. They are particularly numerous in the zone that joins the gizzard with the duodenum. The ontogeny of the neurotensin cells in the gut was studied in rats and chickens. In the rat, the cells are first observed in the jejuno-ileum immediately before birth. The adult frequency is reached 4–5 days later. In the chicken, neurotensin cells first appear in the colon in the 18 day old embryo and in the small intestine two days later (i.e. one or two days before hatching). A few days after hatching, the gut has achieved the adult number of neurotensin cells per unit area.
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  • 96
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 184 (1977), S. 491-497 
    ISSN: 1432-0878
    Keywords: Somatostatin ; Immunocytochemistry ; Human hypothalamus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to identify clearly the nervous structures containing somatostatin in the human hypothalamus, an immunohistochemical localization of this neurohormone was performed at light-microscopic level. Using a antiserum specific to somatostatin and the unlabeled antibody peroxidase-antiperoxidase technique, we have found somatostatin in neurons with cell bodies in an area in the anterior hypothalamus corresponding to the infundibular nucleus. Somatostatin-containing fibers were also detected in the neurovascular zone of the pituitary stalk, suggesting that somatostatin is released in that region to reach the capillaries in the pituitary portal plexus. A large bundle of somatostatin fibers extending from the anterior part of the paraventricular nucleus up to the posterior portion of the mammillary bodies has also been detected. The role of these fibers still remains to be clarified.
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  • 97
    ISSN: 1432-0878
    Keywords: Thyroid gland ; Immunocytochemistry ; Thyroglobulin ; Petromyzon marinus L
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antibodies made against thyroglobulin (TG) were used in an immunocytochemical study for the light and electron microscopic localization of TG in the thyroid gland of the anadromous sea lamprey, Petromyzon marinus, during its upstream migration. TG was found in the follicular lumen and in some colloid droplets within the follicular cells. Except for an immunoreactive product observed in a small portion of the interstitial connective tissue, the location of TG in the lamprey was similar to that in the thyroid of the rat.
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  • 98
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Dipnoi (Protopterus) ; Neurohypophysial hormones ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using the unlabeled antibody peroxidase-antiperoxidase complex (PAP) technique at the light microscopic level, it has been shown that, in the dipnoan preoptico-hypophysial neurosecretory system, vasotocin and mesotocin are synthesized in separate neurons. In the preoptic nuclei, the perikarya of these two types of neurosecretory neurons are not located preferentially. The two types of neurosecretory perikarya give rise to separate vasotocinergic and mesotocinergic axons, respectively. The dipnoan median eminence and neural lobe contain separate vasotocinergic and mesotocinergic nerve fibres, the general distribution of which is described. In the pars distalis and the pars intermedia of the hypophysis, neurohypophysial hormone-containing nerve fibres have not been found.
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  • 99
    ISSN: 1432-0878
    Keywords: Cyproterone acetate ; d-Norgestrel ; Progesterone ; Pars distalis ; adenohypophysis ; Immunocytochemistry ; Dog (Beagle)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of short-term (8 weeks) treatment with different doses of cyproterone acetate (CPA), d-norgestrel (d-N) and progesterone on cells of the pars distalis, as revealed by the immunoperoxidase technique, were studied in cycle-synchronized beagle bitches (first anoestrus). Pituitary glands from non-treated primiparous beagle bitches at the 6th and 9th week of pregnancy were also included. For immunochemical staining specific antisera to the following hormones were used: canine GH, canine PRL, porcine ACTH, bovine TSHβ, bovine LHβ and human FSHβ. Morphological features of high secretory activity in GH cells were evident even after the human oral contraceptive doses of CPA and d-N, and after a dose as low as 0.1 mg/kg/day subcutaneously (s.c.) of progesterone. In contrast, PRL cells did not show any significant treatment-related effects except in those animals which received the highest dose of d-N (0.5 mg/kg/day per os). In this group, as well as in all pregnant bitches, hyperplasia and hypertrophy of PRL cells were found. In the animals treated with the highest doses of CPA (4.0 mg/kg/day per os) and progesterone (42.5 mg/kg/day s.c.) as well as in pregnant bitches, ACTH/MSH and TSH cells showed marked atrophy and regressive changes. Similar morphological signs of depressed secretory activity were also observed in the cells shown to contain FSHβ and/or LHβ as a result of treatment with the highest dose of progesterone and at the 9th week of pregnancy. These structural responses indicate that quantitative and/or qualitative differences may exist between progesterone, the synthetic progesterone derivative CPA and the nortestosterone type progestagen d-N with regard to their effect on pituitary hormone secretion in the beagle bitch.
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 194 (1978), S. 79-102 
    ISSN: 1432-0878
    Keywords: Duodenum ; Endocrine cells ; Differentiation ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development and cytodifferentiation of endocrine cells that produce the gastrointestinal hormones gastrin, cholecystokinin and secretin have been studied by a combined fluorescence-cytochemical, immunocytochemical and ultrastructural approach. The results show that, during development, several ultrastructurally distinct cell types exhibit COOH-terminal gastrin and cholecystokinin immunoreactivity. Furthermore, some cells simultaneously contain both gastrin- and cholecystokinin-specific antigenic determinants. Studies on the time course of development of gastrin and cholecystokinin cells, together with the above-mentioned data, suggest that gastrin cells may be converted into cholecystokinin cells in development. During this period, gastrin, cholecystokinin and secretin cells store the biogenic monoamine, 5-hydroxytryptamine a feature not displayed by the adult counter-parts of these cells. In the adult duodenum, characteristic enterochromaffin (EC) cells store 5-hydroxytryptamin for which, evidence for a possible hormonal role has been presented. Taken together, our data indicate that the differentiation of duodenal endocrine cells occurs in distinct steps, each involving a restriction in the biosynthetic repertoire of the cell.
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