ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Calcium  (61)
  • Springer  (61)
  • American Physical Society
  • MDPI Publishing
  • 1975-1979  (45)
  • 1965-1969  (16)
  • 1935-1939
Collection
Keywords
Publisher
  • Springer  (61)
  • American Physical Society
  • MDPI Publishing
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Intestinal calcium binding protein in uremia (1979)
    Springer
    Calcified tissue international 27 (1979), S. 205-210 
    Details
    ISSN: 1432-0827
    Keywords: Intestine ; Calcium ; Binding ; Protein ; Uremia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In order to assess the usefulness of intestinal biopsies as indicators of end-organ responsiveness to vitamin D in uremic patients, calcium binding activity and calcium binding protein (CaBP) content were measured in intestinal biopsies from 12 uremic patients (glomerular filtration rate〈5.0 ml/min) and 12 adult controls. Values for both were found to vary with the site of biopsy, highest values being obtained in the duodenal bulb, with lower values distally. Values for activity correlated with values for CaBP content in both normals and uremics and no difference was observed between groups. Levels of calcium binding activity and content of CaBP did not correlate with serum immunoreactive parathormone levels, but were directly related to circulating 25-hydroxycholecalciferol (25-OHD) levels. The data show that intestinal CaBP is normal in activity, quantity, and affinity for calcium in malabsorbing uremic patients, and are consistent with the hypothesis that calcium malabsorption in uremia is unrelated to deficiency of intestinal calcium binding protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441187
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Precipitation of calcium phosphates from electrolyte solutions V. The influence of citrate ions (1979)
    Springer
    Calcified tissue international 28 (1979), S. 131-136 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Phosphate ; Citrate ; Precipitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The influence of citrate ions on the precipitation of crystalline apatitic precipitates with low Ca/P molar ratios [octacalcium phosphate (OCP) and calcium-deficient apatites (DA) (system A)] and of the intercrystalline mixtures of calcium hydrogen phosphate dihydrate (DCPD) and DA (system B) was investigated. Samples were prepared by direct mixing of calcium chloride solutions (A, 6·10−3 mol dm−3; B, 1·10−1 mol dm−3) and sodium phosphate solutions (A, 6·10−3 mol dm−3; B, 2·10−2 mol dm−3) containing citrate (0–2·10−3 mol dm−3) and preadjusted to pH 7.4. In the presence of citrate ions: (a) crystal growth of OCP and DA was slowed down; (b) habit modification of DCPD crystals occurred; and (c) equilibration in intercrystalline mixtures of DCPD and DA's was slowed down. All phenomena were caused by surface adsorption of negatively charged ions, most probably CaC6H5O7-, which is the prevalent calcium citrate species under the given experimental conditions. Habit modification of DCPD was induced by preferential adsorption at the (001) crystal plane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441231
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Disordered mineral metabolism produced by ketogenic diet therapy (1979)
    Springer
    Calcified tissue international 28 (1979), S. 17-22 
    Details
    ISSN: 1432-0827
    Keywords: Anticonvulsant ; Ketogenic diet ; Calcium ; Vitamin D ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Vitamin D and mineral metabolism status was examined in five children maintained chronically on combined ketogenic diet-anticonvulsant drug therapy (KG), and the results compared to those obtained in 18 patients treated with anticonvulsant drugs alone (AD) and 15 normal controls. KG patients exhibited biochemical findings of vitamin D deficiency osteomalacia: decreased serum 25-hydroxyvitamin D (25OHD) and calcium concentrations, elevated serum alkaline phosphatase and parathyroid hormone concentrations, decreased urinary calcium and increased urinary hydroxyproline excretion, and decreased bone mass. Although the KG and AD groups demonstrated similar reductions in serum 25OHD concentration, the KG patients exhibited a significantly greater reduction in bone mass. In response to vitamin D supplementation (5000 IU/day), mean bone mass in the KG group increased by 8.1±0.9% (P〈0.001) over a 12-month period. These results suggest that ketogenic diet and anticonvulsant drug therapy have additive deleterious effects on bone mass and that these effects are partially reversible by vitamin D treatment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441213
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Precipitation of calcium phosphates under conditions of double diffusion in collagen and gels of gelatin and agar (1979)
    Springer
    Calcified tissue international 27 (1979), S. 171-176 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Phosphate ; Precipitation ; Double diffusion ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary One-dimensional double diffusion was applied to determine critical concentrations at which the precipitation of calcium phosphates occurs in reconstituted connective tissue collagen and agar gels at 37°C and in gelatin gels at 25°C. Experiments were performed in the presence of unbuffered 0.15 mol dm−3 NaCl, or 0.15 mol dm−3 NaCl-veronal adjusted to pH 7.4. It was found that critical concentrations of precipitation of both precipitating components, CaCl2 and phosphate buffer (pH 7.4), were equimolar and independent of the ratios of initial concentrations of the components. Critical concentrations of precipitation were not affected by the concentrations and kinds of gels used. The first-formed precipitates showed amorphous structure by X-ray diffraction analyses. Infrared (IR) spectra of the precipitates indicated CaHPO4 · H2O to be their predominant species. The molar Ca/P ratio obtained by chemical analyses was 1.08. This precipitate transformed in time into octacalcium phosphate. In all experiments, two very thin membranes of precipitate were formed in the gel column at the onset of precipitation simultaneously on both sides of the actual disc of precipitate. IR spectra and chemical analyses showed that both membranes were identical to the actual precipitation discs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441181
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Factors affecting parathyroid hormone-induced hypophosphatemia and32P specific activity in thyroparathyroidectomized rats (1979)
    Springer
    Calcified tissue international 27 (1979), S. 239-246 
    Details
    ISSN: 1432-0827
    Keywords: Parathyroid hormone ; Calcium ; Plasma phosphate ; Bone phosphate ; Plasma32P ; Specific activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Plasma changes in calcium, phosphate, and their radionuclides were studied in thyroparathyroidectomized (TPTX) rats treated with parathyroid hormone (PTH) for 8 h, this treatment starting 10 h after injection of45Ca and32P. Prior to intravenous infusion or hourly injections of PTH (10 mU/g/h), rats were maintained in one of three ways: on an extended fast (24 h); on a partial fast (10 h); or provided with 10% glucose and 1% calcium lactate overnight as a substitution for solid food. The pattern of change for plasma calcium,45Ca, and45Ca specific activity (S.A.) produced by PTH was not affected by these dietary conditions. The changes in phosphate were as follows: During the experimental (8 h) period, the rate of loss of32P from plasma in control rats was proportional to the length of the fast. This suggests that32P was released into plasma during the experimental period proportional to the ready availability of soft tissue glucose. In rats on an extended fast, PTH was phosphaturic, hypophosphatemic, and increased the rate of loss of32P from plasma without affecting32P S.A. values. In rats fasted for only 10 h, PTH produced similar effects on plasma phosphate and plasma32P values, but also caused a significant fall in plasma32P S.A. After glucose and calcium lactate treatment, PTH-induced phosphaturia was temporarily lost and the marked hypophosphatemia was replaced with a slight hyperphosphatemia. Plasma32P values also rose slightly; therefore, no effect on32P S.A. was produced. It is concluded from these studies that as the result of the phosphaturia caused by PTH, the hypophosphatemia which is produced automatically changes the phosphate gradient between various body compartments, causing phosphate entry into plasma. The authors postulate that this phosphate entering plasma is withdrawn primarily from bone fluid and bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441192
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Anticonvulsant drug-induced osteomalacia: Alterations in mineral metabolism and response to vitamin D3 administration (1979)
    Springer
    Calcified tissue international 27 (1979), S. 13-18 
    Details
    ISSN: 1432-0827
    Keywords: Anticonvulsants ; Calcium ; Vitamin D ; Parathyroid hormone ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Parameters of mineral metabolism were examined in 6 patients with moderately severe anticonvulsant drug-induced osteomalacia. Compared to 15 matched controls, the patients exhibited significantly reduced serum calcium, inorganic phosphate, and 25-hydroxyvitamin D concentration, elevated serum alkaline phosphatase and immunoreactive parathyroid hormone (iPTH) concentration, reduced intestinal47Ca absorption, reduced urinary calcium and increased urinary hydroxyproline excretion, and reduced forearm bone mass. Intestinal absorption of vitamin D3 was normal. Following 4 months of treatment with vitamin D3 (4000 units/day), serum 25-OHD concentration was increased to 3 times mean normal values and all parameters except serum iPTH, urinary calcium excretion, and forearm bone mass were returned to levels not significantly different from normal. Serum iPTH concentration was reduced by 39% (P〈0.05); 24-h urinary calcium excretion rose by 98% (P〈0.001), and forearm bone mass increased by 5.6% (P〈0.05). It is concluded that moderate-dose vitamin D3 supplementation is effective in normalizing parameters of mineral metabolism in this disorder, despite evidence of resistance to the biologic effects of vitamin D.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441155
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The calciuria of increased fixed acid production in humans: Evidence against a role for parathyroid hormone and 1,25(OH)2-vitamin D (1979)
    Springer
    Calcified tissue international 28 (1979), S. 233-238 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; PTH ; 1,25(OH)2D ; Acid ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We measured mineral and acid balances, serum iPTH, urinary cAMP/creatinine, and plasma concentrations of 25OHD and 1,25(OH)2D in 7 healthy adults during control conditions and during increased fixed acid production achieved either by the administration of NH4Cl (N=3) or by increased dietary protein intake (N=4). When acid production was increased, the subjects were in positive acid balance and negative Ca balance because of increased urinary Ca excretion. Serum iPTH fell slightly but urinary cAMP and the plasma levels of vitamin D metabolites did not change. We conclude that the accelerated skeletal and urinary losses of Ca that occur when fixed acid production is increased are not contributed to nor compensated for by the parathyroid-vitamin D endocrine systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02441241
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Vaterite, a constituent of the eggshells of the nonparasitic cuckoos,Guira guira andCrotophagi ani (1979)
    Springer
    Calcified tissue international 29 (1979), S. 63-69 
    Details
    ISSN: 1432-0827
    Keywords: Vaterite ; Calcium ; Eggshells ; Cuckoos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The crystalline spherules occurring in patches on the outer surface of the eggshells ofGuira guira and the bloom on the entire outer surface of those ofCrotophagi ani were shown by X-ray diffraction analysis to be vaterite.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408056
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Regulation of calcium transport in isolated periosteal cells, effects of hormones and metabolic inhibitors (1979)
    Springer
    Calcified tissue international 29 (1979), S. 155-161 
    Details
    ISSN: 1432-0827
    Keywords: Periosteal cells ; Calcium ; PTH ; CT ; Metabolic inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Calcium transport was studied in cells isolated from cultured periostea of 18-day-old chick embryos. Net calcium uptake was stimulated by iodoacetate (IAA) and inhibited by dinitrophenol (DNP). Calcium efflux from the intracellular compartment was inhibited by IAA. Changes in the extra-or intracellular sodium concentration had only minor effects on calcium transport. This indicates that calcium efflux from periosteal cells is probably directly dependent on ATP hydrolysis, whereas calcium-sodium exchange is of less importance. The cation ionophore A23187 stimulated calcium uptake during short incubations but was inhibitory in long incubations. The possible involvement of the mitochondria in this effect is discussed. Parathyroid hormone (PTH) and calcitonin (CT) stimulated the net uptake of calcium in relatively low doses (both 0.01 U/ml or higher). The effects of the hormones on net calcium uptake were not additive. Calcium efflux was not changed in the presence of PTH or CT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408071
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Phytochrome-mediated uptake of calcium in Mougeotia cells (1979)
    Springer
    Planta 146 (1979), S. 31-39 
    Details
    ISSN: 1432-2048
    Keywords: Autoradiography ; Calcium ; Mougeotia ; Phytochrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ca2+ is proposed to function as a messenger in such phytochrome-mediated responses as localized cell growth, intracellular movements, and control of plasma membrane properties. To test this hypothesis, the uptake of Ca2+ in irradiated and non-irradiated regions of individual threads of the green alga Mougeotia was studied with the aid of 45Ca2+ and low temperature autoradiography: 10–20 cells within 40–60 cell-long threads were irradiated for up to 1 min, transferred to darkness for 3 to 10 min, submersed in a radioactive medium for 1 min, washed in an unlabelled medium for 30 min, and then autoradiographed at-80° C for several days. The autoradiographs show that those cells which had been pre-irradiated with red light did take up 2–10 times more Ca2+ than the adjacent non-irradiated cells of the same thread. Cells pre-irradiated with farred light or red light followed by far-red light showed no enhanced uptake of Ca2+. These results might be interpreted to indicate, firstly, that phytochrome-Pfr is involved in the enhanced uptake of Ca2+ and secondly, that the accumulation of radioactive Ca2+ in red light irradiated cells is an expression of an increased intracellular concentration of Ca2+. This interpretation is based on the data that (i) the dark interval between irradiation and labelling precluded the involvement of photosynthesis, (ii) the effect of red light was reversible with far-red light, and (iii) the accumulation of Ca2+ persisted during the long wash-out period. We speculate, that the red light-enhanced accumulation of Ca2+ in Mougeotia cells is caused by a Pfr-mediated increase of the Ca-permeability of the plasma membrane, and perhaps by a Pfr-impeding of an active Ca2+-extrusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381252
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Forced calcium entry and polarized growth of Funaria spores (1979)
    Springer
    Planta 144 (1979), S. 401-406 
    Details
    ISSN: 1432-2048
    Keywords: A23187 gradients ; Calcium ; Germination (moss spores) ; Electric fields-Funaria ; Ionophore gradient ; Moss spores-Polarization ; Spores (moss)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have used both steady electric fields, and gradients of the divalent ionophore, A23187, to control the point at which rhizoids emerge from spores of the common moss Funaria hygrometrica. The spores were grown in a medium containing calcium nitrate as the only major salt. Spores tend to form rhizoids towards the positive electrode, with a half maximal response to a difference of 4–8 mV across each cell. They also tend to form rhizoids towards the end of higher ionophore concentration in response to A23187 gradients. Both of these responses are the same at pH 5.5 and 8.0. Our tentative explanation is that Funaria spores tend to form rhizoids where most calcium enters. However, the point of chloronema emergence is scarcely affected by steady fields of up to 45 mV/cell. Moreover, when steady fields are applied across already developed rhizoids or chloronemata, their subsequent growth is directed towards the negative electrode in both cases, with rhizoids giving a 50% response at only 3—5 mV/cell, and chloronemata being less responsive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380114
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Interaction of bovine rhodopsin with calcium ions (1979)
    Springer
    European biophysics journal 5 (1979), S. 33-41 
    Details
    ISSN: 1432-1017
    Keywords: Rhodopsin ; Calcium ; Reaction kinetics ; Regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The formation of metarhodopsin II in various bovine rhodopsin preparations (rod outer segment (ROS) suspensions and rhodopsin-detergent solutions) was measured by means of flash spectrophotometry. The half-lifetime and formation of metarhodopsin II in ROS did not depend on the calcium concentration in the range of less than 10−9 M (using EGTA or EDTA) to 15×10−3 M calcium at pH values of 5.0, 7.1, and 9.0 (Table 1). The regeneration of rhodopsin from opsin by adding 11-cis retinal to ROS-suspensions and rhodopsin digitonin solutions was measured spectrophotometrically. It was not substantially different in either saline, one containing less than 10−7 M calcium (by adding EGTA), the other containing 10−3 M calcium (Table 2).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535771
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    The effects of Mn2+ and Ca2+ on the prolonged depolarising after-potential in barnacle photoreceptor (1979)
    Springer
    European biophysics journal 5 (1979), S. 223-230 
    Details
    ISSN: 1432-1017
    Keywords: Prolonged depolarising after-potential (PDA) ; Visual pigment ; Invertebrate photoreceptor ; Manganese ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract We have studied the effects on the PDA of modifying intracellular and extracellular concentrations of Ca2+ and Mn2+. The effect of decreased Ca2+ concentration or addition of EGTA is mainly an increase in the PDA amplitude and length. Raising Ca2+ concentration using ruthenium red or high external Ca2+ has the opposite effect. The effect of Mn2+ is much more striking: In the presence of 50–100 mM Mn2+ the PDA is initially greatly depressed but can rise slowly for up to 20 or 30 s (in the dark) until it approaches its original amplitude and time course. Bridge measurements showed that the depression of the PDA corresponds to a depressed conductance and so is not due to an increase in K+ conductance. The Mn2+ effect is potentiated by decreased Ca2+. Appropriate stimulation suppresses the rising PDA as promptly as it does a normal PDA, suggesting that if lateral diffusion is the source of the slow rise, the PDA and PDA-depressing processes must be spatially linked. The action of the anti-PDA is apparently prolonged by both Ca2+ and Mn2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535450
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Effect of external factors on phototaxis of Chlamydomonas reinhardtii (1979)
    Springer
    Archives of microbiology 123 (1979), S. 93-99 
    Details
    ISSN: 1432-072X
    Keywords: Movement ; Phototaxis ; Cations ; Chlamydomonas ; Calcium ; Lanthanum ; Circadian rhythms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of several cations on phototaxis of Chlamydomonas reinhardtii have been studied with the aid of an automated phototaxis monitoring device, coupled with a continuous culture. Sodium, potassium and magnesium ions, if added to the complete nutrient medium, have only slight effects on phototaxis at lower concentrations (10-3 mol), but inhibit at higher concentrations (10-2 mol). This inhibitory effect is not specific because motility is also impaired. Addition of 10-3 mol calcium enhances the phototactic reaction for some hours, but then the stimulation decreases gradually. Addition of 10-2 mol calcium causes strong inhibition. However, the reactivity recovers gradually during the following hours. If 10-3 mol potassium which does not influence phototaxis if added alone is applied simultaneously with calcium, the stimulation by calcium is enhanced. By the addition of 5·10-4—2·10-3 mol Ca2+ or Ca2++K+ cicadian rhythms with an average period length of 24 h are initiated which damp out after 1–2 weeks. If the cells are grown in a calcium deficient medium or if calcium is removed, phototactic activity decreases to very low reaction values or to zero, but is drastically increased immediately after the addition of calcium. The stimulatory effect of Ca2+ ions is specific. Ca2+ cannot be fully substituted by Ba2+ or Sr2+, and phototaxis is reversibly inhibited by lanthanum which is known to inhibit the calcium pump.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403506
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Calcium binding sites in the vesicles of the carotid and aortic body chief cells (1979)
    Springer
    Cell & tissue research 199 (1979), S. 145-151 
    Details
    ISSN: 1432-0878
    Keywords: Carotid body ; Aortic body ; Calcium ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Chief cells of the carotid and aortic body chemoreceptors possess numerous cytoplasmic dense-core vesicles which are known to contain primarily dopamine. Following fixation in solutions containing 50 mM CaCl2, a 20–30 nm electron-dense particle (EDP) is often observed eccentrically located in many of the vesicles. Approximately 44 % of the carotid body and 16 % of the aortic body vesicles contain an EDP. The EDP probably represents the Ca+ + binding site critical to the stimulus-secretion coupling events culminating in exocytosis of these vesicles. The presence of Ca+ + in the cytoplasmic vesicles was verified by electron probe X-ray microanalysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237734
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    The influence of humidity on the mineral composition of tomato plants with special reference to calcium distribution (1979)
    Springer
    Plant and soil 52 (1979), S. 427-435 
    Details
    ISSN: 1573-5036
    Keywords: Ash alkalinity ; Calcium ; Cation distribution ; Humidity ; Magnesium ; Mineral composition ; Oxalate ; Pectate ; Tomato
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Tomato plants grown in water culture under two different humidity regimes (50% R.H. and 95% R.H.) were harvested at intervals over the growth period and cation uptake and calcium distribution investigated. The following results were obtained: 1. Plants in the high humidity regime initially grew faster but at the final harvest after 22 days, dry matter yields were the same. 2. In the high humidity treatment particularly towards the end of the experiment, the growth of the young leaves was disturbed and the plants showed symptoms resembling Ca or B deficiency. Analysis revealed that these tissues were lower in Ca than comparative tissues of the low humidity plants. The converse was true for B. 3. Cation uptake was little affected by the humidity treatment. However, the distribution of calcium within the plant was markedly influenced by humidity. In the high humidity treatment the level of Ca in the young leaves was very low and Ca accumulated in the stems. A high proportion of both Ca and Mg in these younger Ca deficient leaves was found to be associated with pectate. The same trend was observed in the stems, more of the Ca and Mg in this case being bound to oxalate as well as pectate. These results further indicate the possible significance of exchange movement of Ca particularly under low transpiration conditions when Ca transport by mass flow is restricted. 4. Xylem sap analysis showed a close cation-anion balance in all samples. NO3-ion was the predominant anion and the two major cations were K and Ca. This provides further evidence that the upper plant parts provide the major site of NO3-reduction in the tomato plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185585
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    The intestinal handling of calcium by the rat in vivo, as affected by cortisol. Effect of dietary calcium supplements (1978)
    Springer
    Calcified tissue international 25 (1978), S. 1-6 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Intestine ; Growth ; Cortisol ; Hydroxyproline ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary This paper reports the effects of cortisol on intestinal management of calcium and on related changes on bone metabolism. Five groups of 12 rats each fed a standard diet (0.8% Ca) received 2, 6, 16, 32, and 128 mg/kg/day of cortisol hemisuccinate, subcutaneously. After 16 days, intestinal absorption and excretion of Ca were measured with the aid of45Ca. True Ca absorption increased as a function of dose up to 16 mg/kg/day and remained high with the larger doses. Endogenous fecal Ca excretion increased exponentially as a function of the dose from 16 mg/kg/day onwards. Therefore, a dual effect was observed: (a) an increase in true Ca absorption at low cortisol doses (which increased net Ca absorption); and (b) an increase in endogenous fecal Ca excretion at high doses (which reduced net Ca absorption). In no case was a depression of true Ca absorption observed. Growth rate and food conversion efficiency were depressed only with a cortisol dose of 128 mg/kg/day. The urinary excretion of hydroxyproline, pyrophosphate, and aminopolysaccharides decreased with low doses and increased above normal levels with the highest dose. When animals treated with 128 mg/kg/day of cortisol were fed Ca-enriched diets, net Ca absorption improved. Simultaneously, growth rate and food conversion efficiency approached normal values. In these experiments, net absorption of Ca was found to be inversely related to urinary excretion of hydroxyproline. The urinary rate of excretion of hydroxyproline is suggested as an indicator of the effect of a Ca supplement on cortisol affected connective tissue turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010743
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Effects of a single dose of fluoride on calcium metabolism (1978)
    Springer
    Calcified tissue international 26 (1978), S. 199-202 
    Details
    ISSN: 1432-0827
    Keywords: Fluoride ; Calcium ; Phosphate ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Fluoride 27 mg was given perorally to 14 subjects. It was found that the serum fluoride concentration increased followed by a decrease to normal levels during 24 h. Serum concentrations of calcium and phosphate decreased initially whereas those of serum immunoreactive parathyroid hormone increased. After 24 h the measured quantities were within normal limits. The results are discussed with reference to mineralization of hard tissues and to fluoride treatment of osteoporotic patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013258
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Potentiation of the effects ofSolanum malacoxylon extracts on rat intestinal phosphate and calcium absorption by incubation with ruminal fluid (1978)
    Springer
    Calcified tissue international 26 (1978), S. 215-219 
    Details
    ISSN: 1432-0827
    Keywords: Solanum malacoxylon ; Vitamin D metabolites ; Rickets ; Phosphate ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of a partially purified aqueous extract ofSolanum malacoxylon (SM) leaves and of an SM extract incubated with ruminal fluid (RF) prior to administration on intestinal phosphate and calcium absorption in rachitic rats were compared with 1α, 25-dihydroxy-vitamin D3[1α,25-(OH)2-D3] using a duodenal loop in situ method. The time course responses elicited by both extracts were qualitatively similar to that of 1α, 25-(OH)2-D3. However, a single dose of SMRF was significantly more effective in stimulating32P absorption than an equivalent dose of SM. Part of this difference can be accounted for by incomplete saturation of the phosphate transport system with the level of SM employed. Treatment with rumen potentiated the effects of SM on45Ca absorption to a lesser extent. Extraction of SMRF with nonpolar organic solvents and purification of the lipid extract by chromatography on Silica Gel G thin-layer plates and on Sephadex LH-20 columns yield two fractions which promote intestinal32P absorption. The bioactive fraction eluting first from the Sephadex LH-20 column migrates similarly as 1α,25-(OH)2-D3. The greater effectiveness of SMRF extracts on intestinal phosphate and calcium absorption may be tentatively attributed to the release of 1α,25-(OH)2-D3 from the corresponding glycoside, shown previously to be present in SM, and to steroid modification during incubation with rumen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013261
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Selective stimulation of net calcium efflux from chick embryo tibiae by parathyroid hormone in vitro (1978)
    Springer
    Calcified tissue international 25 (1978), S. 227-232 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010774
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Influence of partially purified extracts ofSolanum malacoxylon on bone resorption in organ culture (1978)
    Springer
    Calcified tissue international 26 (1978), S. 39-45 
    Details
    ISSN: 1432-0827
    Keywords: Solanum malacoxylon ; Bone culture ; Resorption ; Calcium ; Osteoclasts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The water-soluble active principle of the plantSolanum malacoxylon (SM) was partially purified by column chromatography, and its bone-resorbing activity was tested by using an organ culture system of 18-day fetal mouse fibulae prelabeled with45Ca. Three series of experiments were performed. In the first series, the aqueous extract of SM was submitted to Sephadex G-25 chromatography to separate the active substances. From six collected fractions only two exhibited reproducible bone-resorbing activity as indicated by an increased release of45Ca from bone rudiments. In the second series, the active fractions were combined and lyophilized to a powder which was dissolved in the culture media to obtain the concentrations of 5, 25, 50, and 100 μg/ml. The addition of this saltfree material resulted in a dose-related accentuation of45Ca release from fetal mouse bones into the medium. Histologically, the treated fibulae showed greater numbers of osteoclasts than the controls and a disappearance of bone trabeculae. In the third series, the active material was further purified on Sephadex LH-20 column. From four collected fractions, only one showed bone-resorbing activity in vitro. It is concluded that the purified active factor of SM exerts a direct effect on bone. It stimulates the mobilization of bone calcium in vitro by increasing the population of osteoclasts. The nature of the active principle remains unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013232
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    A proposed cellular mechanism for calcium transport in the intestinal epithelial cell (1978)
    Springer
    Calcified tissue international 26 (1978), S. 71-79 
    Details
    ISSN: 1432-0827
    Keywords: Absorption ; Calcium ; Mitochondria ; Intestinal epithelium ; Potassium-pyroantimonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Intracellular transport of calcium from the apical to the basal-lateral region of the intestinal epithelial cell was invetigated in duodenum from normal fed, fasted, and calcium-loaded rats. The process was followed with time using electron microscopy with potassium pyroantimonate to precipitate calcium. The observations made were subjected to morphometric analysis. The specificity of the method was demonstrated in the villus cell by resistance to micro-incineration and by absence of deposits following exposure to EGTA. Using this method calcium was seen in cells from calcium-fed rats at the microvillus border, in the Golgi zone, and within the internal compartments of the mitochondria. In cells from fasted rats calcium was not seen. Mitochondria were found largely at the apex of the cell and were free of detectable calcium. By 5 min, in the cells of fasted rats given a calcium load, the calcium had reached the Golgi apparatus and the inner mitochondrial compartment. After 15 min mitochondria were heavily loaded with calcium and had moved to the basal region of the cell. These observations suggest that mitochondria play an important role in absorption of calcium and appear to transport this ion from the apex to the basal region of the cell where entry into the capillaries takes place.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013237
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Calcium uptake and survival of Bacillus stearothermophilus (1978)
    Springer
    Archives of microbiology 119 (1978), S. 17-24 
    Details
    ISSN: 1432-072X
    Keywords: Thermophilic bacteria ; Bacillus stearothermophilus ; thermostability ; Calcium ; Transport ; Survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The calcium transport in resting vegetative cells of Bacillus stearothermophilus was studied by determining the retention of 45Ca in a membrane filter assay. The kinetics of death by vegetative cells, when suspended in buffer at 55°C, was also investigated. The calcium influx required the presence of an energy source, e.g. glucose-1-phosphate and the system exhibited saturation kinetics. The requirements for survival of the thermophilic cells reflected those of the calcium transport system. Thus, cells treated with nitrogen gas showed an increased thermal stability and a decreased efflux of calcium. The initial velocity of calcium influx correlated linearly with the survival of the cells after 1 min heating at 55° C. Lanthanum inhibited calcium influx and reduced survival. Magnesium did not inhibit calcium influx but could replace calcium as a stabilizing agent. The results suggest that the thermophilic cells are not intrinsically heat stable but survive due to a high cellular concentration of divalent ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407922
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Catharanthine: A novel stimulator of pancreatic enzyme release (1978)
    Springer
    Cell & tissue research 192 (1978), S. 277-284 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas ; Calcium ; Vinca alkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The plant alkaloid, catharanthine, was shown to stimulate release of amylase from pancreatic fragments and to cause extensive degranulation of pancreatic acinar cells with accumulation of membrane material in the Golgi region. The extent and time course of maximal catharanthine stimulation was comparable to that induced by the cholinergic analog bethanechol. Antimycin inhibited the action of catharanthine while atropine did not. Removal of Ca2+ from the incubation medium inhibited amylase release induced by catharanthine but did not affect release induced by bethanechol. Catharanthine induced a delayed release of 45Ca2+ from prelabeled pancreatic fragments as compared to bethanechol. It is suggested therefore that catharanthine activates the physiological pathway controlling amylase release by causing a rise in cytoplasmic Ca2+ but the mechanism by which this occurs is different from that caused by physiological secretagogues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220745
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Cold-induced insulin release in vitro: Evidence for exocytosis (1978)
    Springer
    Cell & tissue research 194 (1978), S. 387-398 
    Details
    ISSN: 1432-0878
    Keywords: Isolated pancreatic islets ; Temperature ; Exocytosis ; Insulin ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Exposure of isolated pancreatic islets (mouse or rat) to low temperature (2° C) evoked a threefold increase in insulin release irrespective of the glucose concentration in the incubation medium. Cold-induced release was transient and rewarming to 37° C restored the sensitivity of B-cells to glucose stimulation. In islets cooled to 2° C, exocytotic profiles could easily be detected both by thin-section and freeze-fracture electron microscopy. As revealed by the freeze-fracture technique, the number of exocytotic profiles per membrane area was increased three-to fourfold as compared to islet cells incubated at 20° C. This was paralleled by intracellular fusion of secretory vesicles. Cold-induced insulin release was not affected by theophylline, cytochalasin B, omission of extracellular Ca++ or D600. Replacement of extracellular Na+ with choline or sucrose suppressed the increase in insulin release and in frequency of exocytotic profiles recorded after exposure to 2° C. It is suggested that a redistribution of Ca++ from intracellular stores, possibly mediated by an increase in intracellular Na+, triggers exocytosis of insulin granules upon exposure to cold.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236160
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    The effect of the ionophore A23187 on amylase release, cellular integrity and ultrastructure of mouse pancreatic acini (1978)
    Springer
    Cell & tissue research 186 (1978), S. 287-295 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas ; Calcium ; Ionophore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of the Ca2+ ionophore A 2317 on pancreatic amylase and lactate dehydrogenase (LDH) release, cellular electrolyte balance and ultra-structure were studied with the use of incubated pancreatic fragments. A 23187 (0.3 μM) in the presence of Ca2+, increased amylase release but at higher concentrations (1–10 μM) also increased LDH release and increased uptake of 14C-sucrose with concomitant loss of tissue K+ and gain in Na +. The ultrastructure of the majority of acini appeared normal and showed depletion of zymogen granules. Microtubules and microfilaments which have been implicated in the release process were normal or increased in number. In the absence of Ca+ the ionophore had no effect on secretion, cellular integrity or ultrastructure. It is concluded that A 23187 in the presence of Ca2+ increases amylase release by a mechanism comparable to the terminal steps in stimulussecretion coupling induced by physiological secretagogues. This provides further evidence that amylase release is mediated by a rise in cell Ca2+ although the mechanisms of the ionophore- and physiological secretagogue-induced rise in Ca+ are probably different. High concentrations of ionophore (〉 1 μM) also induce Ca2+ dependent damage in a fraction of the cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225538
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Calcium and sulphur in neurosecretory granules and calcium in mitochondria as determined by electron microscope X-ray microanalysis (1978)
    Springer
    Cell & tissue research 186 (1978), S. 453-463 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretory granules (Insects) ; Mitochondria ; Calcium ; Sulphur ; Microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sections of neurosecretory cells fixed in glutaraldehyde and osmium tetroxide were studied by means of an EMMA-4 analytical microscope. Secretory granules in neurosecretory cells of the corpus cardiacum and of the brain, both in the desert locust Schistocerca and in the blowfly Calliphora, as well as neurosecretory granules in posterior pituitaries of the frog Rana and of the albino rat all contain a high concentration of calcium. A distinct sulphur peak was also a constant feature. In neurosecretory cells of the corpus cardiacum of Schistocerca the chromatin contained a high concentration of calcium. The mitochondria also contained much calcium, but part of this disappeared during preparation except when fixative and wash contained calcium chloride. By block staining with uranyl acetate most calcium is displaced from the mitochondria, whereas most of the calcium remains in the neurosecretory granules. Since the calcium peaks in spectra from neurosecretory granules appear of similar size, regardless of variations in the preparative procedure, this calcium must be firmly bound. The possible role of the calcium bound to the neurosecretory substance is discussed. The presence of sulphur in insect neurosecretory granules indicates the presence of a protein besides the hormone, i.e., an insect neurophysin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224934
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    The temperature dependency of45Ca diffusion in bovine enamel (1977)
    Springer
    Calcified tissue international 24 (1977), S. 173-177 
    Details
    ISSN: 1432-0827
    Keywords: Enamel ; Calcium ; Diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The diffusion of45Ca ions in sound bovine enamel at pH 7.0 was studied as a function of temperature in the range 20°–40°C. The experimental data show that the diffusion is governed by two processes with activation energies of about 0.7 and 1.3 eV respectively. These values are considerably larger than the activation energy of calcium ion diffusion in water (0.2 eV). The diffusion process with the activation energy of 1.3 eV is dependent upon the calcium concentration in solution. A model based on the complex pore structure of enamel and on interactions of diffusing ions with the enamel constituents is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223312
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Diffusion of45Ca in bovine enamel (1977)
    Springer
    Calcified tissue international 24 (1977), S. 59-64 
    Details
    ISSN: 1432-0827
    Keywords: Enamel ; Calcium ; Exchange ; Diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The penetration of45Ca ions into whole bovine enamel from an aqueous solution was studied as a function of the Ca content in the solution. A sectioning technique was employed to measure the penetration of45Ca into the enamel. Probably only Ca ions occupying surface positions in the hydroxyapatite crystallites participate in the exchange process at the solution-enamel interface. The fraction of Ca ions participating in the exchange was 2% of the total number of Ca ions. Two different diffusion processes occur; firstly, a process governed by a diffusion coefficient, D1 ranging from about 5×10−14 to 2×10−12 cm2/s and strongly dependent on the calcium concentration in the solutions; and secondly a process with a concentration-independent diffusion coefficient, D2, with a value of 2.8×10−12 cm2/s. It is assumed that the 2 diffusion types correspond to intra-and interprismatic transport, respectively. A model based on the pore structure of dental enamel and on surface charges on hydroxyapatite crystallites is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223297
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    The measurement of Ca2+ effluxes from bone (1977)
    Springer
    Calcified tissue international 24 (1977), S. 113-117 
    Details
    ISSN: 1432-0827
    Keywords: Bone membrane ; Calcium ; Ion fluxes ; Calvarium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary To facilitate the study of membrane function in the control of the flow of ions into and out of bone, it was desirable to develop a system for the direct quantitation of unidirectional effluxes of calcium and phosphate from bones. Based on a mathematical analysis of the problem, a specially designed Ussing chamber was developed which proved successful. Calvaria from 2-day-old rat pups, 3-day chicks and adult mice were evaluated. Calcium influxes which exceeded the corresponding effluxes were observed in the neonatal calvaria but not with those from adult mice. Also, an asymmetry in efflux was observed in rat calvaria, the inner side of the skull showed a higher efflux than did the external side. no such asymmetry was seen with calvaria from chicks or mice. This new technology should permit a further exploration of the role of the bone membrane in electrolyte homeostasis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    The effect of fluoride on bone of rats fed diets deficient in calcium or phosphorus (1977)
    Springer
    Calcified tissue international 22 (1977), S. 9-17 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010341
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    On the state of anionic groups of demineralized matrices of bone and dentine (1977)
    Springer
    Calcified tissue international 22 (1977), S. 275-284 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010366
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    A new tracer method for the calculation of rates of bone formation and breakdown in osteoporosis and other generalised skeletal disorders (1977)
    Springer
    Calcified tissue international 22 (1977), S. 191-206 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010358
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Calcium deficiency, pregnancy, and lactation in rats (1977)
    Springer
    Calcified tissue international 23 (1977), S. 87-94 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Osteoporosis ; Lactation ; Chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The calcium homeostatic mechanism was challenged in adult female rats by feeding them a calcium-deficient diet containing oxalate, and by subjecting them to pregnancy and lactation. The regimen caused a substantial weight loss, especially in those animals which reared their young well. Severe hypocalcaemia was observed in the lactating rats. Serum-P was slightly elevated. The content of hydroxyproline in serum was considerably elevated, reflecting the degree of calcium deprivation. Serum proteins were least influenced. The calcium depriving regimen reduced the growth of long bones, but did not stop it. The ash content of the bones was considerably reduced, the degree of reduction depended on the degree of calcium deprivation. Ash as percentage of total bone organ was reduced, but not to the same extent as total ash. Analyses of different parts of femur showed that the proximal and distal parts had lost more bone mineral than the diaphyseal shaft. The ash content of cortical bone tissue from the femur was estimated by a volumetric method. No differences were observed between test groups and controls, indicating that no measurable amounts of bone mineral had been removed from the walls of the vascular canals or by osteocytic osteolysis. Planimetric determinations on cross sections from femora disclosed that a great amount of bone had been removed from the endosteal surface of the diaphysis, while the periosteal surface demonstrated reduced bone apposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02012771
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    The early mineralization of enamel (1977)
    Springer
    Calcified tissue international 24 (1977), S. 271-274 
    Details
    ISSN: 1432-0827
    Keywords: Enamel ; Mineralization ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The potassium pyroantimonate technique was used to study the cellular distribution of calcium during the early mineralization of enamel in rat molar tooth germs at the electron microscope level. Differing patterns of calcium distribution were observed in the ameloblast seemingly associated with the appearance of Tomes' process. In the early secretory ameloblast calcium pyroantimonate deposits were observed within the Golgi apparatus, within coated vesicles, within mitochondria and associated with the inner aspect of the cell membrane. However, with the development of Tomes' process the ameloblasts no longer demonstrated these discrete deposits of calcium pyroantimonate. Instead they showed a diffuse cytoplasmic staining pattern with no preference for any particular organelle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223327
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    A model-independent comparison of the rates of uptake and short term retention of47Ca and85Sr by the skeleton (1977)
    Springer
    Calcified tissue international 22 (1977), S. 183-189 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Strontium ; Bone ; Mathematical modelling
    Source: Springer Online Journal Archives 1860-2000
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02010357
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Localisation histochimique du calcium dans la colloïde des vésicules thyroïdiennes du rat (1977)
    Springer
    Calcified tissue international 24 (1977), S. 275-278 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Thyroid ; Calcium ; Thyroïde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les auteurs utilisent une solution de Glyoxal bis 2-hydroxyanil à basse température pour localiser le calcium dans la thyroïde. Grâce à cette technique qui limite les mouvements ioniques, ils observent que le calcium situé principalement dans la colloïde est résorbé en même temps qu'elle lors d'une stimulation par le froid.
    Notes: Summary With a Glyoxal bis 2-hydroxyanil alcoholic solution at −25°C, the calcium was localized in frozen thyroid slices. The limited ionic movement permits seeing that the calcium situated principally in the colloid is resorbed at the same time by a low temperature stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02223328
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Our present knowledge of calcium or hydrogen ions as transmitters in the vertebrate rod outer segments (1977)
    Springer
    European biophysics journal 3 (1977), S. 55-58 
    Details
    ISSN: 1432-1017
    Keywords: Rhodopsin ; Rods ; Phototransduction ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Difficulties in testing the possible role of calcium as a Transmitter in the R.O.S. are discussed. A comparison is made with the Sarcoplasmic Reticulum system where calcium flux are easily measured. The latest results reviewed on intact cellular structures are highly indicative but not yet conclusive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00536454
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Calcium ion, a putative intracellular messenger for light-adaptation in Limulus ventral photoreceptors (1977)
    Springer
    European biophysics journal 3 (1977), S. 141-143 
    Details
    ISSN: 1432-1017
    Keywords: Calcium ; Limulus ; Photoreceptors ; Adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Calcium ion fulfills several criteria for identifying an intracellular messenger for light-adaptation in Limulus photoreceptors. Direct injection of Ca++ mimicks two aspects of light-adaptation; sequestration of intracellular calcium tends to prevent light-adaptation; and light induces an increase in intracellular Ca++ as demonstrated by two independent techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535809
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    On the mechanism of conductance control of the arthropod visual cell membrane (1977)
    Springer
    European biophysics journal 3 (1977), S. 145-151 
    Details
    ISSN: 1432-1017
    Keywords: Visual cell membranes ; Invertebrates ; Ion channels ; Activation of light channels ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract It is assumed that “dark channels” determine a permanent dark conductance of the arthropod visual cell membrane. The light stimulus causes a transient opening of “light channels”. The ion selectivity of dark channels and light channels is roughly described. Factors influencing the activation of light channels, as membrane energy metabolism, membrane potential and adjusted calcium ion concentration are specified. The mechanism of the action of calcium ions on the conductance of the visual cell membrane is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535810
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    The sarcoplasmic reticulum and associated plasma membrane of trunk muscle lamellae in Branchiostoma lanceolatum (Pallas) (1977)
    Springer
    Cell & tissue research 181 (1977), S. 169-196 
    Details
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Branchiostoma lanceolatum ; Fibre types ; Sarcoplasmic reticulum ; Sarcolemma ; Calcium ; X-ray micro-analysis ; Freeze-fracturing ; Replica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The trunk muscle lamellae of Amphioxus is made up of cross-striated lamellae about 1 μm thick. Transverse tubules are absent, but numerous subsarcolemmal vesicles are found in both tissue blocks and minced samples after aldehyde and osmium fixation, embedding and sectioning. The vesicles contain a granular matrix, range in diameter from 30 to 200 nm and constitute about 3 to 6% of the muscle fibre volume. 8 out of 10 vesicles are found above the Z and I-bands. In the presence of oxalate, electron dense precipitates form within the vesicles. Energy-dispersive X-ray microanalysis reveals the presence of Calcium in these precipitates. The area of the plasma membrane is about 2 μm2/μm3 muscle fibre volume. The corresponding area of sarcoplasmic membrane is ca. 1 μm2/μm3. About 20% of the plasma membrane is directly overlaid and coupled to the sarcoplasmic vesicles. A thin surface coat is present all over the lamellae, but ruthenium red staining indicates that the coat is slightly concentrated above the sarcoplasmic vesicles. Freeze-fracture replicas reveal tightly packed coarse granular material in the vesicular membrane and less concentrated and smaller particles in the plasma membrane. The latter particles are seen somewhat less commonly above the vesicles than on the rest of the plasma membrane. Likewise, direct replicas of lamella spread on glass slides and freeze-dried, reveal a distinct pattern in the surface coat or its underlying structures, corresponding to the Z and I-bands. In the scanning electron microscope the general arrangement of the sarcoplasmic vesicles could be examined. In addition, numerous defects in the plasma- and vesicular membranes indicate a strong adhesion between the two. It is concluded that the trunk muscle lamellae of Amphioxus have a sarcoplasmic reticulum consisting of subsarcolemmal vesicles with calcium sequestrating properties at Z and I-level. Further that the plasma membrane and its surface coat is probably specialized above the vesicles as compared to the rest of the surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219979
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Effect of calcium depletion and subsequent repletion on parathyroids, parafollicular (C) cells and bone in the growing pig (1976)
    Springer
    Cell & tissue research 168 (1976), S. 373-384 
    Details
    ISSN: 1432-0878
    Keywords: Calcium ; Bone ; Parathyroid ; Parafollicular cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the chief cells of the parathyroid gland and thyroid parafollicular (C) cells and the morphology of bone in calcium depletion and subsequent repletion were examined in young growing pigs. A low calcium diet resulted in osteopenia, increased removal of the cartilaginous core, osteoclasia and osteocytic osteolysis. Subsequent repletion quickly returned bone to normal. In pigs fed the low calcium diet, there was a marked depletion of secretory granules but a striking increase in the number of microtubules in chief cells. Increasing the calcium content of the diet to normal quickly returned the ultrastructural appearance of chief cells to apparent normal. In the initial response to calcium repletion, chief cells exhibited large number of lysosomes and occasionally prominent paracrystalloid bodies. Electron microscopic examination of parafollicular (C) cells of the thyroid gland failed to reveal differences in ultrastructure between test and control pigs. These findings support the view that bone resorption following calcium deficiency may be the result of a secondary hyperparathyroidism rather than of calcium deficiency per se.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215314
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    The subcellular localization of calcium in vertebrate smooth muscle: Calcium-containing and calcium-accumulating structures in muscle cells of mouse intestine (1976)
    Springer
    Cell & tissue research 169 (1976), S. 221-231 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Calcium ; Sarcoplasmic reticulum ; Mitochondria ; Microprobe analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intracellular localization of calcium by means of cytochemical techniques was studied in smooth muscle cells of mouse intestine. When the lead acetate method according to Carasso and Favard (1966) was used calcium was found in mitochondria and sarcoplasmic reticulum and occasionally between the myofilaments. The active ATP-dependent accumulation of calcium into cell structures was investigated by the oxalate method (Heumann and Zebe, 1967). After appropriate treatment the only structures of smooth muscle cells which contained calcium oxalate (identified by microprobe analysis) were elements of the sarcoplasmic reticulum. The results are discussed in relation to the role of calcium in the control of muscle activity during the contraction-relaxation cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214210
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    The effect of the ionophore A23187 on the ultrastructure and electrophysiological properties of frog skeletal muscle (1976)
    Springer
    Cell & tissue research 173 (1976), S. 193-209 
    Details
    ISSN: 1432-0878
    Keywords: Muscle ; Ionophore A23187 ; Calcium ; Muscular dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The divalent cation ionophore A23187 has three major effects on the thin cutaneous pectoris muscle of frog: (1) The membrane potential is depolarized, an action that is found only when the [Ca2+] of the bathing saline is very low. (2) It causes an increase in resting tension and the development of contraction. This action is produced at both normal and low values of [Ca2+]o and is, therefore, independent of Ca2+ entry and of changes in Em. The ionophore is believed to act primarily by releasing Ca2+ from intracellular stores. (3) It causes major ultrastructural damage to the muscle filaments. It is believed that this damage is the result of the action of A23187 on the sarcoplasmic reticulum and the elevation of [Ca2+]i and we suggest that the action of this ionophore may serve as a useful model for the study of certain myopathies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221375
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Ultrastructural evidence for a direct connection between the myocardial granules and the sarcoplasmic reticulum in the cardiac ventricle of Myxine glutinosa (L.) (1975)
    Springer
    Cell & tissue research 163 (1975), S. 353-363 
    Details
    ISSN: 1432-0878
    Keywords: Specific heart granules (Cyclostome) ; Atrial granules ; Calcium ; Uranophilic core substance ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The occurrence of structural connections between myocardial granules and tubular elements of the sarcoplasmic reticulum in the cardiac ventricle of the Atlantic hagfish is described. The core substance of the myocardial granules is shown to be uranophilic and in this respect similar to the granular cores within the lumen of the sarcoplasmic reticulum. After application of CaCl2-containing fixatives, the ultrastructure of the core substance of these organelles resembles that described for calcium-containing structures in vertebrate glial cells. Incidences of uranophilic core substance in the extracellular space suggest a secretory function of the myocardial granules. Possible implications of the sarcoplasmic reticulum and the myocardial granules in storage, intracellular transport, and secretion of bound calcium are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219469
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Are mitochondria directly involved in biological mineralisation? (1969)
    Springer
    Calcified tissue international 3 (1969), S. 103-105 
    Details
    ISSN: 1432-0827
    Keywords: Mitochondrion ; Calcium ; Excretion ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058652
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Skeletal uptake of simultaneously ingested fluoride and calcium in the rat (1969)
    Springer
    Calcified tissue international 3 (1969), S. 340-347 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Calcium ; Fluoride ; Ingestion ; compatibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des expériences ont été faites sur le rat afin de tester les possiblités d'ingestion perorale simultanée de fluor (F) et de calcium (Ca) en proportions calculées pour traitement de certaines ostéopénies humaines. F sous forme de Na2PO3F et Ca sous forme de gluconate de calcium (CaGluc) n'influençaient pas l'un l'autre quant à l'utilisation par le squelette (fémur). Une viscosité élevée, produite par l'addition d'amidon ou de cellulose carboxyméthylée (CMC) à la solution ou dilution ingérée, augmentait l'utilisation du F même si CaGluc était remplacé par citrate de calcium, qui en soi avait un effet réducteur modéré sur l'utilisation du F. Le glycérophosphate de calcium réduisait fortement l'utilisation du F même en présence de CMC. L'utilisation du F comme NaF était fortement réduite par CaGluc, même en présence de CMC. Les concentrations testées de Na2PO3F, NaF ou CMC n'influençaient pas l'utilisation squelettique de Ca comme CaGluc.
    Abstract: Zusammenfassung Es wurden Rattenexperimente mit markierten Substanzen durchgeführt, um die Auswirkung simultaner peroraler Gaben von Fluor (F) und von Calcium (Ca) zu prüfen, und zwar in einem Verhältnis, das für die Behandlung gewisser menschlicher Osteopenien berechnet wurde. Fluor in Form von Na2PO3F und Ca in Form von Calciumgluconat (CaGluc) interferieren gegenseitig nicht bei der Verwertung durch das Skelet (Femur). Eine hohe Viscosität der eingegebenen Lösung oder der Aufschlämmung, die durch Zusatz von Stärke oder Carboxymethylcellulose (CMC) erzielt wurde, erhöhte die Verwertbarkeit von F sogar wenn CaGluc durch Calciumcitrat ersetzt wurde, welches die F-Verwertung leicht reduzierte. Calcium-glyzerophosphat verminderte die Fluoraufnahme in den Knochen stark, sogar in Anwesenheit von CMC. Die Verwertung von F als NaF war stark herabgesetzt durch CaGluc, selbst beim Vorhandensein von CMC. Die untersuchten Konzentrationen von Na2PO3F, NaF oder CMC hatten keinen Einfluß auf die Calciumaufnahme im Skelet in Form von CaGluc.
    Notes: Abstract Rat experiments with labelled compounds were carried out in order to test the possibilities of simultaneous peroral supply of fluorine (F) and calcium (Ca) in proportions calculated for treatment of certain human osteopenias. F in the form of Na2PO3F and Ca in the form of calcium gluconate (CaGluc) did not interfere with each other's utilisation by the skeleton (femur). A high viscosity produced by adding starch or carboxymethyl cellulose (CMC) to the ingested solution or slurry increased the utilisation of F even when CaGluc was replaced by calcium citrate, which moderately reduced F utilisation. Calcium glycerophosphate strongly reduced F utilisation even in the presence of CMC. The utilisation of F as NaF was strongly reduced by CaGluc, even in the presence of CMC. The tested concentrations of Na2PO3F, NaF or CMC did not influence the skeletal utilisation of Ca as CaGluc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058676
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Relationship between iron, calcium and phosphate during experimental cutaneous calcinosis (1969)
    Springer
    Calcified tissue international 4 (1969), S. 224-230 
    Details
    ISSN: 1432-0827
    Keywords: Calcinosis ; Calcium ; Iron ; Phosphate ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La calcification de la peau (calciphylaxie) provoquée par l'administration sous-cutanée de chlorure de fer chez des rats sensibilisés par le dihydrotachystérol (DHT) est précédée par une déposition sélective de fer (décelable à la microscopie électronique) à la surface des fibres collagènes. Les analyses à la microsonde prouvent que les taux de calcium et de phosphore sont augmentés à l'endroit de l'injection du chlorure de fer même sans l'administration préalable de DHT; cependant, l'apatite ne se forme que chez les animaux prétraités par le DHT. La quantité et le degré de cristallinité de la matière inorganique sont presque identiques au sixième et au trentième jour de l'expérience.
    Abstract: Zusammenfassung Durch elektronenmikroskopische Untersuchungen wurde festgestellt, daß die durch subcutane Verabreichung von Eisenchlorid bei Dihydrotachysterin-sensibilisierten Ratten herbeigeführte Hautverkalkung durch eine selektive Eisenablagerung auf der Oberfläche der Kollagenfibrillen eingeleitet wird. Die Röntgenmikroanalyse zeigt an, daß die lokale Calciumund Phosphorkonzentration bereits nach Eiseninjektion allein ansteigt, während Apatitbildung nur in den mit DHT vorbehandelten Tieren erfolgt. Ausmaß und Menge der Kristallisation sind am 6. und 30. Tage nach Versuchsbeginn fast gleich.
    Notes: Abstract Calcification of the skin (calciphylaxis) induced by the subcutaneous administration of iron chloride to dihydrotachysterol (DHT)-sensitized rats is preceded by the selective deposition of iron (visible with electron microscopic techniques) on the surface of collagen fibrils. Electron probe X-ray microanalysis indicates that the injectionof iron alone suffices to increase local concentrations of calcium and phosphorus; however, apatite formation occurs only in animals pretreated with DHT. The amount and degree of crystallinity of the inorganic material is very similar on the sixth and thirtieth day after the beginning of the experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279125
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Mitochondrial granules in chondrocytes (1969)
    Springer
    Calcified tissue international 3 (1969), S. 184-193 
    Details
    ISSN: 1432-0827
    Keywords: Mitochondria ; Calcification ; Calcium ; Chondrocytes ; Growth plate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des cultures d'épiphyse prélevées sur des rats et des souris ont été étudiées sous le microscope électronique. Un profile de granules mitochondriques de densité électronique a été trouvé. Les chondrocytes dans la zone proliférative avaint peu de granules, alors que ceux des zones successives ont montré une augmentation progressive de leur nombre et densité jusqu'à ce que la zone de calcification provisoire ait été atteinte. Cette zone a montré une distribution périphérique de mitochondries et une réduction du nombre et de la densité des granules mitochondriques. Du calcium isotopique 47 a été utilisé autoradiographiquement pour déterminer la location de calcium dans ces cellules. Des grains ont été trouvés sur les membranes R.E. et sur la plupart des mitochondries. La preuve d'un profile de ces granules et de leur rapport spatial avec la face de minéralisation indique une action éventuelle de mitochondries dès le début de la calcification de la matrice.
    Abstract: Zusammenfassung Epiphysekulturen von Ratten und Mäusen wurden unter dem Elektronenmikroskop untersucht. Ein Profil von mitochondrischen Körnchen mit elektronischer Dichte wurde gefunden. Chondrozyten in der Proliferationszone wiesen wenig Körnchen auf, während die der nachfolgenden Zonen allmählich an Zahl und Dichte zunahmen, bis die Zone der provisorischen Verkalkung erreicht wurde. Diese Zone zeigte eine periphere Verteilung der Mitochondrien und eine Abnahme in Zahl und Dichte der mitochondrischen Körnchen. Isotopes Kalzium 47 wurde autoradiographisch verwendet, um die Lage des Kalziums in diesen Zellen zu bestimmen. Körnchen wurden auf den E.R.-Membranen und auf einem Großteil der Mitochondrien gefunden. Der Nachweis eines Profils dieser Körnchen und ihres räumlichen Verhältnisses zur Mineralisierungsfläche weist auf einen möglich Einfluß der Mitochondrien mit Beginn der Matrixverkalkung hin.
    Notes: Abstract Rat and mice epiphyseal growth plates were studied with the electron microscope. A gradient of mitochondrial electron-dense granules was found. Chondrocytes in the proliferative zone had few granules, while those of the succeeding zones showed a gradual increase in number and density until the zone of provisional calcification was reached. This zone showed a peripheral distribution of mitochondria and a decrease in the number and density of mitochondrial granules. Isotopic47calcium was used autoradiographically to determine the location of calcium in these cells. Grains were found over the endoplasmic reticulum membranes and over most mitochondria. The demonstration of a gradient of these granules and their spatial relation to the mineralization front suggests a possible involvement of mitochondria in the onset of matrix calcification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058661
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Strontium and calcium contents of bone density fractions (1969)
    Springer
    Calcified tissue international 4 (1969), S. 174-179 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Strontium ; Bone ; Mineral
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La proportion Sr/Ca dans l'os est à peu près la même que dans le sérum tandis que les poudres d'hydroxyapatite suspendues dans des solution physiologiques font une distinction contre le strontium. On trouva que la proportion Sr/Ca des fractions de différentes densités d'os compact de tibia de rat en forme de poudre augmentait avec augmentation de la densité jusqu'à une valeur un peu supérieure à celle observée dans le sérum. L'explication pourrait être qu'une barrière cellulaire ôte le calcium par préférence au strontium du fluide d'os ou bien qu'une accentuation précoce de la proportion Sr/Ca dans l'os se réfléchit dans les fractions de densité supérieure.
    Abstract: Zusammenfassung Das Verhältnis Sr/Ca im Knochen ist annähernd dasselbe wie es im Serum vorliegt, während in einer physiologischen Lösung von pulverisiertem Hydroxyapatit das Sr zugunsten des Ca benachteiligt wird. Es wurde festgestellt, daß das Sr/Ca-Verhältnis von Fraktionen verschiedener Dichte von pulverisierten Rattentibiae mit zunehmender Dichte anstieg, und zwar bis zu einem Wert, der etwas höher lag als der im Serum beobachtete. Dies ließe sich so erklären, daß eine Zellbarriere beim Entzug aus der Knochenflüssigkeit Ca dem Sr vorzieht; oder aber daß sich eine frühzeitige Betonung des für den Knochen typischen Sr/Ca-Verhältnisses in den Fraktionen höherer Dichte widerspiegelt.
    Notes: Abstract The Sr/Ca ration in bone is approximately the same as in serum, whereas hydroxyapatite powders suspended in physiological solutions discriminate against strontium. It was found that the Sr/Ca ratio of various density fractions of powdered compact bone of rat tibia increased with increasing density to a value slightly higher than that observed in the serum. The explanation could be that a cellular barrier removes calcium preferentially to strontium from the bone fluid, or that early accentuation of the bone Sr/Ca ration is reflected in the higher density fractions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279118
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Serum calcium and phosphate changes in thyroidectomized dogs (1969)
    Springer
    Calcified tissue international 4 (1969), S. 188-192 
    Details
    ISSN: 1432-0827
    Keywords: Serum ; Calcium ; Phosphate ; Calcitonin ; Thyroidectomy ; Metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Après ablation des glandes thyroïdes de chiens, sans lèser les glandes parathyroïdiennes supérieurs, les taux en calcium et phosphate sériques et la gravité spécifique sont comparées avec des valeurs d'un groupe de chiens, chez lesquels une intervention simulée est réalisée. Immédiatement après thyroïdectomie, le taux de phosphate est plus élevé que le taux de calcium. Ce taux de phosphate se maintient plus longtemps à un niveau élevé que le taux de calcium, après thyroïdectomie. Le rapport entre l'augmentation du phosphate et le taux initial de phosphate sérique chez chaque animal indique des variations normales de la calcitonine d'un animal à l'autre.
    Abstract: Zusammenfassung Bei Hunden wurde die Thyreoidea entfernt, ohne die Parathyreoidea zu verletzen. Der Gehalt des Serums an Calcium und Phosphat sowie sein spezifisches Gewicht wurden mit den Werten verglichen, welche nach einer Scheinoperation bei einer Kontrollgruppe von Hunden bestimmt wurden. Unmittelbar nach der Thyreoidektomie war der Phosphatspiegel höher als jener des Calciums. Der Phosphatspiegel blieb nach der Thyreoidektomie länger hoch als der Calciumspiegel. Das Verhältnis zwischen dem Phosphatanstieg und dem Ausgangswert des Serumphosphates bei jedem Tier wies auf normale Variationen der Calcitonin-Konzentration bei verschiedenen Tieren hin.
    Notes: Abstract The thyroid glands were removed from dogs without interfering with the superior parathyroid glands. Levels of serum calcium, phosphate, and specific gravity were measured subsequently for 24 hours, and these values were compared with values obtained from a control group of dogs in which a mock operation was done. Immediately after thyroidectomy, the level of phosphate was greater than the calcium level. The phosphate level remained high longer after thyroidectomy than did the calcium level. The relationship between the increase in phosphate level and the initial serum phosphate value in each animal indicated normal variations in calcitonin levels in different animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279121
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    The relationship of dietary calcium intake to radiographic bone density in normal and osteoporotic persons (1969)
    Springer
    Calcified tissue international 4 (1969), S. 245-256 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Densitometry ; X-ray ; Diet ; Calcium ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'ingestion quotidienne de calcium of été déterminée en interrogeant 398 individus, âgés de 15 à 90 ans. Le rapport entre l'ingestion de calcium et la minéralisation vertébrale, mesurée par densitométrie radiographique quantitative, est fiable mais cependant significatif. Chez 53 personnes, atteintes d'ostéoporose, comparées à un nombre égal d'individus, d'âges similaires, les valeurs de la minéralisation vertébrale sont 60 pour cent plus faibles que celles du groupe témoin. L'ingestion totale moyenne de calcium est plus faible de 21 per cent chez les ostéoporotiques. Chez les sujets, à ingestion unique de calcium, les patients du groupe témoin ingèrent preque le double de calcium que le groupe des ostéoporotiques. Une diminution moyenne de l'ingestion calcique est notée avec l'âge. Il semble qu'il existe une diminution de l'absorption calcique avec l'âge, l'ostéoporose ou les deux, ainsi qu'un besoin plus grand en calcium chez les sujets âgés pour assurer l'équilibre en calcium. Indépendamment de l'homéostase calcique, un équilibre négatif en calcium augmente la résorption osseuse, et diminue l'ostéogenèse. De nombreux facteurs interviennent dans l'étiologie et la pathogénie de l'ostéoporose: les résultats de cette étude indique que la présence de calcium alimentaire est l'un de ces facteurs.
    Abstract: Zusammenfassung Die tägliche Calciumeinnahme wurde anhand einer Befragung von 398 Personen im Alter von 15–90 Jahren geschätzt. Die Korrelation der Calciumeinnahme und der Mineralisation der Wirbelsäule, wie sie röntgenologisch durch quantitative Messung der Dichte festgestellt wurde, war niedrig, aber durchwegs signifikant. Bei 53 Osteoporose-Patienten, die mit 53 Kontrollpersonen gleichen Alters verglichen wurden, waren die Mineralisationswerte der Wirbelsäule um 60% niedriger als jene der Kontrollgruppe, und die durchschnittlich geschätzte Gesamt-Calciumeinnahme der Osteoporotiker war um 21% tiefer. Von den Exploranden, die Angaben über eine gleichmäßige Calciumaufnahme machten, nahmen die Kontrollpersonen beinahe doppelt so viel Calcium ein als diejenigen mit Osteoporose. Im Durchschnitt wurde eine Verminderung der Calciumeinnahme mit fortschreitendem Alter festgestellt. Es ergibt sich deutlich, daß die Calciumabsorption mit dem Alter, bei Osteoporose oder in der Kombination dieser beiden Faktoren abnimmt, und daß eine größere Calciumeinnahme bei älteren Personen nötig wäre, um eine positive Calciumbilanz aufrechtzuerhalten. Ungeachtet der Komplexität der Calciumhomöostase, kann eine negative Calciumbilanz schließlich dazu führen, daß mehr Knochen resorbiert als gebildet wird. Demzufolge sollte bei erkanntem Bedürfnis eine adäquate Calciumeinnahme gesichert sein. Es ist eine Tatsache, daß viele Faktoren an der Ätiologie und Pathogenese der Osteoporose beteiligt sind; die Resultate dieses Berichtes unterstützen die Wahrscheinlichkeit, daß das Calciumangebot in der Nahrung einer dieser Faktoren ist.
    Notes: Abstract Lifetime daily calcium intake was estimated through interview of 398 individuals from 15 to 90 years of age. The correlation of calcium intake with vertebral mineralization as determined by quantitative radiographic densitometry was low but persistently significant. In 53 persons with osteoporosis matched by age with 53 individuals from the control group, vertebral mineralization values were 60% lower than those of the control group, and the mean estimated total calcium intake in osteoporotics was 21% lower. In those persons reporting a single lifetime calcium intake, the control patients ingested almost twice as much calcium as those with osteoporosis. A mean decrease in calcium intake with advancing years has been shown. Evidence points to a decrease in calcium absorption with age, osteoporosis, or both, as well as a greater need for calcium intake in the elderly to maintain a positive calcium balance. Regardless of the intricacies of calcium homeostasis, a negative calcium balance leads eventually to greater bone resorption than formation, hence the rationality of insuring an adequate calcium intake with recognized nutritional needs. Evidence suggests that many factors are involved in the etiology and pathogenesis of osteoporosis; the data in this report support the likelihood that availability of calcium in the diet is one of them.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279127
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Are mitochondria directly involved in biological mineralisation? (1969)
    Springer
    Calcified tissue international 3 (1969), S. 100-102 
    Details
    ISSN: 1432-0827
    Keywords: Mitochondria ; Calcium ; Mineralisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058651
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Effect of high dietary strontium levels on bone and egg shell calcium and strontium (1969)
    Springer
    Calcified tissue international 4 (1969), S. 180-184 
    Details
    ISSN: 1432-0827
    Keywords: Strontium ; Calcium ; Bone ; Shell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Des poules ont été nourries avec une alimentation riche en strontium stable. Des concentrations de strontium de 3000 p.p. m. à 50000 p.p.m. montre une augmentation nette en strontium du tibia, alors que le contenu en calcium n'est pas modifié. Les concentrations en calcium sérique diminue, lorsque le strontium alimentaire augmente. Le calcium des coquilles d'oeufs diminue progressivement avec l'augmentation du strontium alimentaire, alors que le contenu en strontium des coquilles présente une augmentation correspondante. Des analyses de diffraction par rayons X des os et des coquilles ne permettent pas de déterminer sous quelle forme le strontium est déposé.
    Abstract: Zusammenfassung Die Resultate einer Verfütterung von hohen stabilen Strontiumdosen an Hühnern werden erläutert. Strontiumzusätze zur Nahrung in der Höhe von 3000–50000 p.p.m. führten zu einer signifikanten Zunahme des Strontiumgehaltes der Tibia und verursachten keine wesentlichen Änderungen des Calciumgehaltes. Die Calciumkonzentration im Plasma verminderte sich, wenn der Nahrung ansteigende Strontiummengen zugegeben wurden. Mit zunehmendem Strontiumzusatz zur Nahrung zeigte der Calciumgehalt der Eischale eine fortlaufende Abnahme, während sich der Strontiumgehalt entsprechend erhöhte. Durch Röntgendiffraktionsanalysen der stark Strontium-haltigen Knochen und Eischalen konnte nicht festgestellt werden, in welcher Form das Strontium abgelagert wurde.
    Notes: Abstract The results of feeding high dietary levels of stable strontium to hens are reported. Dietary levels of strontium from 3,000 p.p.m. to 50,000 p.p.m. showed a significant increase in strontium content of the tibia bone and essentially no change in the calcium content. Plasma calcium concentration was shown to decrease with increasing dietary strontium treatment. Egg shell calcium showed a progressive decrease with increasing dietary strontium treatment, whereas the strontium content has a corresponding increase. X-ray diffraction analyses of bones and shells containing large amounts of strontium were unsuccessful in evaluating the from in which strontium was deposited.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279119
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    An electron microscope and autoradiographic study of the calciferous glands of the earthworm,Lumbricus terrestris (1969)
    Springer
    Calcified tissue international 4 (1969), S. 193-201 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Carbonate ; Gland ; Ultrastructure ; Spherolith
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Les cellules activement sécrétantes des glandes riches en calcium deLumbricus terrestris ont une forme en dôme. La partie basale de la cellule présente de nombreux prolongements ramifiés. Ces prolongements contiennent de nombreuses mitochondries, ainsi que des invaginations de la membrane formant des vésicules qui migrent dans diverses parties de la cellule. Le noyau irrégulier est en position centrale. La région supranucléaire contient surtout de l'ergastoplasme, plusieurs appareils de Golgi et de nombreuses granules provenant de l'appareil de Golgi. Ces granules augmentent de taille et sont rejetées dans le sinus de la glande, où elles se modifient et se calcifient pour donner des sphérolithes. Des radioautographics glandulaires, obtenues 1/2 heure après injection de Ca45, montrent une localisation isotopique, située presque exclusivement dans les cellules; 4–24 heures après, l'isotope se localise dans les sphérolithes de la cavité glandulaire. Ces cellules semblent assurer deux fonctions liées à la production de sphérolithes: 1. absorption et transport de calcium de la région basale vers la surface cellulaire et 2. formation d'une matrice protéique qui se calcifiera.
    Abstract: Zusammenfassung Die aktivsezernierenden Zellen der calcifizierenden Drüsen vonLumbricus terrestris sind annähernd kuppelförmig gestaltet. Der untere Teil dieser Zellen besteht aus unzähligen ineinandergreifenden Zellfortsätzen. Diese Fortsätze enthalten zahlreiche Mitochondrien und membranöse Einstülpungen, welche Bläschen bilden, die zu den verschiedenen Regionen der Zelle wandern. Der Zellkern ist unregelmäßig und zentral angeordnet. Die supranukleäre Region ist zu einem großen Teil mit grobem endoplasmatischem Reticulum und mehreren Golgi-Komplexen sowie zahlreichen Granula, die von den Golgi-Komplexen stammen, ausgefüllt. Diese Granula vergrößern sich und werden in den Drüseninus ausgestoßen, wo sie schließlich reorganisiert und mineralisiert werden, um Sphärolithen zu bilden. 1/2 Std nach Injektion von Ca45 wurde die Drüse entfernt; eine Radioautographie zeigte, daß das Isotop beinahe ausschließlich in den Zellen lokalisiert war; 4–24 Std später befand sich das Isotopin den Sphärolithen der Drüsenhöhlung. Diese Zellen sind anscheinend an zwei für die Bildung von mineralisierten Sphärolithen notwendigen Funktionen beteiligt: 1. an der Calcium-Absorption und deren Transport von der Basalregion bis zur Zelloberfläche; 2. an der Bildung einer Proteinmatrix, in welcher die Mineralisation stattfindet.
    Notes: Abstract The actively-secreting cells of the calciferous glands ofLumbricus terrestris are roughly dome shaped. The basal part of the cell consists of numerous interdigitating cell processes. These processes contain numerous mitochondria and membranous infoldings, forming vesicles which migrate to various regions of the cell. The nucleus is irregular and centrally located. The supranuclear region is occupied to a great extent by the rough endoplasmic reticulum, several Golgi complexes and numerous granules derived from the Golgi complexes. These granules enlarge and are extruded into the gland sinus, where they eventually become reorganized and mineralized to give rise to spheroliths. Radioautographs of glands removed 30 min following injection of45Ca showed uptake of the isotope located almost exclusively in the cells; 4–24 h later the isotope was located in the spheroliths in the gland cavity. These cells apparently perform two functions necessary for the production of mineralized spheroliths, 1, absorption and transport of calcium from the basal region to the cell surface and 2, the elaboration of a protein matrix in which mineralization occurs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279122
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Measurement of growth and resorption of bone in rats fed meat diet (1969)
    Springer
    Calcified tissue international 4 (1969), S. 291-304 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Fluorescence ; Resorption ; Deposition ; Calcium ; Microradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Divers agents chimiques, colorés, fluorescents et se localisant dans les os, à savoir la tétracycline, l'alazazine rouge S et le DCAF, ont été administré en série à des rats sevrés et on a mesuré le taux de la formation et de la résorption osseuse sur les coupes transversales du tiers supérieur de la diaphyse. Ici la formation osseuse périostale s'effectue progressivement avec peu de changement endostéal. Avec alimentation carnée, la croissance des rats est significativement restreinte pendant la première semaine, mais se rétablit ensuite. Bien qu'il y ait croissance des os, ceux-ci ne se minéralisent pas normalement et ils deviennent rapidement fragiles et amincis. La résorption osseuse est lente d'abord, puis s'accelère pendant 2–3 semaines pour atteindre un taux de 15μ par jour, après quoi elle se ralentit de nouveau. Bien que le taux de formation osseuse soit réduit, en comparaison avec celui des os normaux, la résorption s'effectue environ deux à trois fois plus rapidement que la croissance osseuse. Des études microradiographiques sur des rats à régime carné mais carencés en calcium ont permis la constatation suivante: tandis que la résorption s'effectue à la marge endostéale et que la formation osseuse a lieu sur l'aspect périostéal, la matière osseuse nouvellement formée est moins calcifiéc que chez les témoins.
    Abstract: Zusammenfassung Einige farbige, fluoreszierende, knochensuchende Chemikalien, z. B. Tetracyclin, Alazarin-Rot S und CDAF, wurden nacheinander an entwöhnten Ratten verabreicht, worauf man die Knochenbildungs- und Knochenresorptionswerte an hartgeschliffenen Schnitten des oberen Drittels der Diaphyse gemessen hat. Hier findet fortschreitend periostale Knochenbildung statt, mit geringer Veränderung des Endosteums. Bei Fleischdiät wird das Körperwachstum während der ersten Woche erheblich beschränkt; danach aber normalisiert es sich wieder. Obwohl die Knochen noch wachsen, zeigen sie keine normale Mineralisierung und werden schnell zerbrechlich und dünn. Die Knochenresorption ist anfangs langsam, dann beschleunigt sie sich während einer Zeitspanne von 2–3 Wochen bis auf 15 μ pro Tag, um sich dann wieder zu verlangsamen. Während die Knochenbildungsgeschwindigkeit relativ zum Normalwert heruntergesetzt wird, verläuft die Resorption ungefähr 2–3mal so schnell wie die Knochenbildung. Mikroradiographische Untersuchungen an mit Fleisch ernährten Ca-armen Ratten haben bestätigt, daß während die Resorption am Endosteumrande stattfindet und sich die Knochenbildung an der Periostenfläche fortsetzt, die neugebildete Knochensubstanz weniger kalzifiziert ist, als die der Kontrolltiere.
    Notes: Abstract Different coloured, fluorescent bone-seeking chemicals, viz., tetracycline, Alizarin Red S, and DCAF, have been administered sequentially to weanling rats and the rate of formation and resorption of bone measured from hard-ground cross sections of the upper third of the diaphysis of the femur. On a meat diet, bodily growth is significantly restricted for the first week and then recovery occurs. While bones grow they fail to mineralize normally and rapidly become fragile and rarefied. Resorption of bone is at first slow, then accelerates for a period of 2–3 weeks to about 15μ/day and then slows again. While the rate of bone formation is reduced relative to normal bone, resorption proceeds at approximately two to three times the rate of bone growth. Microradiographic studies confirm tht while resorption occurs on the endosteal margin and formation proceeds on the periosteal aspect of meat fed Ca-deficient rats, new bone is less calcified than that in control animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279132
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Calcium binding by a lipid extract ofBacterionema matruchotii (1968)
    Springer
    Calcified tissue international 2 (1968), S. 296-298 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Lipid ; Bacteria ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé On a fait ce travail pour determiner si le facteur responsable pour la liaison de calcium par un calcifableBacterionema matruchotii est dans la fraction lipide de la cellule. Des cellules congelees et sechees ont ete extraites par le chloroform-methanol. La fraction de chloroform-methanol, les cellules extraites et les cellules non traitees ont ete examinees pour la liaison de calcium. La fraction du chloroform-methanol et les cellules non traitees avaient la liaison de calcium. Les cellules extraites n'en avaient pas.
    Abstract: Zusammenfassung Diese Arbeit wurde durchgeführt um festzustellen, ob sich der Faktor für die Calcium-bindung, durch das calcifizierendeBacterionema matruchotii, in der Lipoidfraktion befindet. Die lyophiilisierten Zellen wurden mit Chloroform-Methanol extrahiert. Die Chloroform-Methanol-Fraktion, die extrahierten Zellen, sowie die nicht behandelten Zellen wurden auf eine Calciumbindung hin untersucht. Die Chloroform-Methanol-Fraktion und die nicht behandelten Zellen demonstrierten eine Calciumbindung. Die extrahierten Zellen hingegen nicht.
    Notes: Abstract This work was done to determine whether the factor responsible for calcium binding by a calcifiableBacterionema matruchotii is in the lipid fraction of the cell. Freeze-dried cells were extracted with chloroform-methanol. The chloroform-methanol fraction, the extracted cells and untreated cells were examined for calcium binding. The chloroform-methanol fraction and the untreated cells bound calcium. The extracted cells did not.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279217
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Inhibition of local calcergy by topical application of calciphylactic challengers (1968)
    Springer
    Calcified tissue international 2 (1968), S. 67-76 
    Details
    ISSN: 1432-0827
    Keywords: Calcergy ; Calciphylaxis ; Calcium ; Metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Chez le rat, des expériences ont montré que, sauf de rares exceptions, les calcifications produites au site d'injection d'acétate de plomb, de chlorure de cérium, chlorure de calcium ou de permanganate de potassium sont complètement prévenues ou fortement inhibées par l'application locale simultanée de provocateurs calciphylactiques, mais non par des agents non provocateurs. Malgré quelques exceptions (attribuées à des interrelations chimiques spécifiques entre certaines des substances utilisées), cette curieuse corrélation entre l'efficacité calciphylactique provocatrice et le pouvoir anticalcergique est, d'après le test χ2, hautement significative (P〈0,001).
    Abstract: Zusammenfassung Nach subcutaner Injektion von Bleiacetat, Ceriumchlorid, Calciumchlorid oder Kaliumpermanganat tritt an der Injektionsstelle eine starke Verkalkung auf. Bis auf sehr wenige Ausnahmen kann diese durch gleichzeitige lokale Anwendung von calciphylaktischen Provokatoren verhütet oder weitgehend unterdrückt werden. In dieser Beziehung sind nicht provolatorisch wirkende Stoffe inaktiv. Trotz der wenigen Ausnahmen (die wahrscheinlich auf spezifische, chemische Wechselwirkungen zwischen manchen der untersuchten Substanzen beruhen) ist dieser merkwürdige Zusammenhang zwischen calciphylaktisch provozierender und anticalcergischer Aktivität, nach dem χ2-Test berechnet, statistisch hochsignifikant (P〈0,001).
    Notes: Abstract Experiments on rats indicate that, with very few exceptions, the calcification which occurs at subcutaneous sites of treatment with lead acetate, cerium chloride, calcium chloride or potassium permanganate is completely blocked or severely inhibited by simultaneous topical application of calciphylactic challengers but not of non-challengers. Despite the few exceptions (which are thought to depend upon specific chemical interactions between some of the compounds tested) this singular correlation between calciphylactic challenging and anticalcergic potency, is highly significant by the Chi-square-test (P〈0.001).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279195
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Calcium binding by chondroitin sulfate (1968)
    Springer
    Calcified tissue international 2 (1968), S. 253-261 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Ion ; Binding ; Chondroitin ; Cartilage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La liaison du calcium par le sulfate de chondroitin C a été étudiée en utilisant des méthodes biologiques et physicochimiques pour la détermination quantitative du calcium ionique. Les valeurs moyennes pour logK j, le logarithme de la constante de formation non corrigée d'un complexe calcium-sulfate de chondroitin C, sont 1,64 par la technique de cœur de grenouille, 1,55 par la méthode de murexide, 1,39 par l'ultrafiltration et 1,04 par l'électrode sélective du calcium. L'ordre de grandeur de ces valeurs suggèrent que le sulfate de chondroitin C a une capacité de liaison pour calcium relativement élevée, mais les valeurs calculées pour un paramètre d'échangeK p indiquent que le calcium a une affinité faible pour le polysaccharide.
    Abstract: Zusammenfassung Die Bindung von Calcium mit Chondroitinsulfat C wurde untersucht mittels biologischer und physikalisch-chemischer Methoden für die quantitative Bestimmung des ionischen Calciums. Im Durchschnitt ergab logK j, der Logarithmus der unkorrigierten Formationskonstante für einen Calciumchondroitinsulfatkomplex, 1,64 mit der Technik des Froschherzens, 1,55 mit der Murexidmethode, 1,39 mittels Ultrafiltration und 1,04 mit den Calciumselektiven Elektroden. Die Größe dieser Werte zeigt, daß Chondroitinsulfat eine relativ hohe Bindungskapazität für Calcium hat, die berechneten Werte für einen AustauschparameterK p jedoch, daß Calcium eine kleine Affinität für Polysaccharide hat.
    Notes: Abstract The binding of calcium by chondroitin sulfate C was studied by employing biological and physicochemical methods for the quantitative determination of ionic calcium. Mean values for logK j, the logarithm of the uncorrected formation constant for a calcium-chondroitin sulfate complex, were 1.64 with the frog heart technique, 1.55 with the murexide method, 1.39 with ultrafiltration and 1.04 with the calcium selective electrode. The magnitude of these values suggests that chondroitin sulfate has a relatively high binding capacity for calcium, but calculated values for an exchange parameterK p indicate that calcium has a low affinity for the polysaccharide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279213
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Calcium transport by the intestine: A model and comment on vitamin D action (1968)
    Springer
    Calcified tissue international 2 (1968), S. 301-313 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Absorption ; Vitamin D
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279219
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Effect of disuse osteoporosis on bone composition: the fate of bone matrix (1968)
    Springer
    Calcified tissue international 2 (1968), S. 20-29 
    Details
    ISSN: 1432-0827
    Keywords: Bone Atrophy ; Bone Resorption ; Calcium ; Collagen ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé Atrophie osseuse d'immobilisation était induite par section de la plexus brachial et/ou désarticulation de la coude. Après 9 bis 12 semaines de désuétude huméri intactes furent examinés par rayons X et leur qualités physiques déterminés. Les humérientiers furent isolés, dégraissés, desséchés au poids constant, et leur teneur en cendre d'os et collagène déterminés. Huit des 10 huméri immobilisés monstrérent radiodensité diminué. La jambe inusitée monstra perte parallèle en poids sec et poids sans gras (−23.2%), en collagène (−25.3%), et en cendre d'os (−26.1%) en comparaison de la jambe normale. Les données monstrèrent que la portion plus grande du tissu osseux perdu en atrophie osseuse d'immobilisation est remplacée par de l'eau, du gras, et des autres matériels organiques inconnus plutôt que par tissu fibreux, et que collagène est perdu en proportion du minéral. La perte proportionellement plus grande du collagène et de la cendre d'os que du poids sec et poids san gras semble dû à une augmentation du matériel organique, non-collagéne, non-lipide, kprobablement protéine.
    Abstract: Zusammenfassung Immobilisations-Knochenatrophie wurde in 10 erwachsenen Hunden herbeigeführt durch Brachialplexusschnitt und/oder Ellenbogenexartikulation. Nach 9–12 Wochen der Immobilisation wurden die intakten Humeri unter Röntgenstrahlen untersucht und ihre physischen Eigenschaften bestimmt. Derintakte Humerus wurde isoliert, entfettet, zu konstantem Gewicht getrocknet und der Knochenaschengehalt und Kollagengehalt bestimmt. Acht der 10 experimentellen (immobilisierten) Humeri demonstrierte Beweis von verringerter Röntgendichte. Die immobilisierte Extremität zeigte ähnlichen Verlust in trockenem, fettfreiem Gewicht (−23,2%) in Kollagen (−25.3%) und Knochenasche (−26,1%) im Vergleich zur normalen Extremität. Die Date deuten an, daß der Hauptanteil des Verlustes des Knochengewebes (bei Immobilisations-Knochenatrophie) von Wasser, Fett und anderen unidentifizierten organischen Substanzen ersetzt wird, als von Faserngewebe und daß Kollagen und Knochenasche im gleichen Verhältnis verloren gehen. Der größere, proportionale Verlust an Kollagen und Knochenasche, eher als der Verlust an fettfreiem Gewicht, scheint in der Zunahme an nicht kollagener, nicht lipoider, organischer Substanz, vermutlich Protein, zu liegen.
    Notes: Abstract Disuse bone atrophy was induced in 10 adult dogs by means of brachial plexus section and/or elbow disarticulation. After 9 to 12 weeks of disuse intact humeri were examined by X-ray, and their physical properties determined. Thewhole humeri were isolated, defatted, dried to constant weight, and their mineral and collagen content determined. Eight out of 10 experimental (non-used) humeri demonstrated evidence of decreased radiodensity. The non-used limb demonstrated parallel loss in dry, fat-free weight (−23.2%), in collagen (−25.3%), and in mineral (−26.1%), as compared to the normal limb. The data indicated that the major portion of the lost bone tissue in disuse osteoporosis is replaced by water, fat, and other unidentified organic materials rather than fibrous tissue, and that collagen is lost in equal proportion to mineral. The proportionatelly greater loss of collagen and mineral than of dry, fat-free weight appears to be due to an increase of non-collagenous, non-lipid organic material, presumably protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279190
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...