Changes in phospholipid metabolism dependent on calcium-regulated myoblast fusion

1988 ◽  
Vol 66 (10) ◽  
pp. 1110-1118 ◽  
Author(s):  
Victor S. Sauro ◽  
Gregory A. Brown ◽  
Michael R. Hamilton ◽  
Craig K. Strickland ◽  
Kenneth P. Strickland
Keyword(s):  
Calcium Content ◽  
Phospholipid Metabolism ◽  
Myoblast Fusion ◽  
Myoblast Differentiation ◽  
Phospholipid Content ◽  
Phospholipid Synthesis ◽  
Normal Medium ◽  
Low Calcium ◽  
High Calcium ◽  
Fusion Competent Myoblasts

Fusion-competent myoblasts can be prevented from fusing (differentiating) by reducing medium calcium concentrations from 1.65 mM to less than 50 μM. Fusion is completely retarded after 24 h but is noticeable after 48 h and significant after 72 h in low-calcium medium. After 24 h in low-calcium medium, a rapid, synchronous fusion can be initiated by return to normal (high-calcium) medium. Calcium content increases over threefold during myoblast differentiation and closely parallels the fusion process. Phospholipid content is also dependent upon the state of differentiation. Myotubes (fused myoblasts) have an almost twofold greater content of lipid phosphate per milligram of protein compared with that of myoblasts; this increase is localized to increased contents of phosphatidylcholine and pooled phosphatidylinositol – phosphatidylserine. Phospholipid synthesis (32Pi incorporation) is markedly stimulated four- to five-fold when myoblasts grown in low-calcium medium are switched to normal medium. These significant increases are observed in all the major phospholipids studied, predominantly in phosphatidylcholine and pooled phosphatidylinositol – phosphatidylserine, and most noticeably in phosphatidylinositol 4,5-bisphosphate. Furthermore, we show that phosphatidylinositol 4,5-bisphosphate prelabelled with myo-[2-3H]inositol is rapidly degraded after switching from low-calcium medium to normal medium. These changes are not observed in myotubes treated similarly, which suggests that the changes in phospholipid metabolism may be fusion related. These results support a proposal by another author, which suggests that phosphatidylinositol 4,5-bisphosphate breakdown may play an important regulating role in myoblast differentiation.

Adrenalectomy decreases NaCl intake of rats fed low-calcium diets

1996 ◽  
Vol 270 (1) ◽  
pp. R11-R21 ◽  
Author(s):  
M. G. Tordoff
Keyword(s):  
Salt Intake ◽  
Calcium Content ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium ◽  
High Salt Intake ◽  
High Calcium ◽  
Bone Content ◽  
Adrenocortical Hormone ◽  
Intact Rats

Five studies were conducted to characterize the effects on NaCl intake of the interaction between adrenalectomy (ADX) and dietary calcium. Intact rats fed low-calcium diets (0 or 25 mmol Ca2+/kg diet) approximately quadrupled intake of 300 or 500 mM NaCl solution relative to intact rats fed diets with moderate or high calcium content (125, 150, or 500 mmol Ca2+/kg diet) ADX approximately doubled NaCl intake of rats fed moderate or high-calcium diets but decreased NaCl intake of rats fed low-calcium diets to levels similar to those of ADX rats fed moderate of high-calcium diets. Aldosterone replacement (2.4 micrograms/day sc) reduced NaCl intake of ADX rats fed control diets to below levels of intact controls, but the same treatment to ADX rats fed low-calcium diet had no effect on NaCl intake. The reduction in NaCl intake produced by ADX in rats fed low-calcium diet could not be attributed to general debilitation, damage to the adrenal medulla, or altered metabolism of sodium or calcium (i.e., plasma concentration, bone content, or balance). It is proposed that an adrenocortical hormone other than aldosterone mediates the high salt intake of the calcium-deprived rat, and thus the adrenal has both inhibitory and excitatory actions on NaCl intake.

scholarly journals An Appraisal of Compressive Strength of Concrete Incorporated with Chemically Different Fly Ashes

2020 ◽  
Vol 14 (1) ◽  
pp. 188-199
Author(s):  
Atsushi Suzuki ◽  
Dinil Pushpalal ◽  
Hiroo Kashima
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Physical Properties ◽  
Calcium Content ◽  
Fly Ashes ◽  
Fly Ash Concrete ◽  
Low Calcium ◽  
High Calcium ◽  
Applicable Range ◽  
Compressive Strength Of Concrete

Introduction: Generally, the compressive strength of fly ash concrete differs depending on the properties of fly ash. This strength difference causes difficulties for concrete engineers to guarantee the strength of supplied concrete. Methods: This research firstly carried out the compressive strength tests on the concrete incorporated with fly ash possessing various chemical composition, which are high and low calcium fly ashes. The linear and nonlinear regression analyses were adopted to build the strength prediction model. Results: The chemical and physical properties of procured fly ash with high and low calcium contents have been quantified. Specifically, the compressive strength of concrete with high calcium fly ash demonstrates a strong correlation with calcium content, rather than physical properties such as the surface area and loss of ignition. Therefore, the compressive strength on 28th day can be assessed by a simple formula, taking CaO content of fly ash as an independent variable. In further, the strength on an arbitrary day can be predicted based on the 28th day strength and the replacement rate of fly ash. Conclusion: The two-step framework proposed in this research enables concrete engineers to evaluate the compressive strength of fly ash concrete with an error rate of less than 30%, within the applicable range addressed in this research.

Variasi Penambahan Tepung Daun Kelor (Moringa Oleifera Lam.) pada Pembuatan Flakes Ditinjau dari Sifat Fisik, Sifat Organoleptik dan Kadar Kalsium

2017 ◽  
Vol 19 (1) ◽  
pp. 31-35
Author(s):  
Frieda Rosita Majid ◽  
Nur Hidayat ◽  
Waluyo Waluyo
Keyword(s):  
Physical Characteristic ◽  
Nutritional Value ◽  
Calcium Content ◽  
Organoleptic Characteristics ◽  
High Calcium ◽  
Randomized Experimental Design ◽  
Leaf Powder ◽  
The Difference ◽  
The Tropics ◽  
Moringa Oleifera Lam

Background:Moringa (Moringaoleifera Lam.) Is a plant of high nutritional value, grows scattered in the tropics and sub-tropics, but utilization is still low. Each section has its benefits Moringa one part is the Moringa leaves contain a high calcium. In 100 grams of material, fresh Moringa leaves contain as much as 440 mg of calcium in the form of flour whereas if it contains as much as 2,003 mg of calcium. One of its use in the manufacture of flakes added. Objective: Know the difference physical harateristi, organoleptic characteristic and calcium levels in flakes variations addition of Moringa leaf powder. Methods: The study is a randomized experimental design with simple, includes four kinds of treatments, two replications with two experimental units. Observations of physical characteristic were analyzed by descriptive, the organoleptic characteristic of data analysis using statistical test Kruskal-Wallis continued Mann-Whitney and methods of test calcium content using permanganometri then the data were analyzed descriptive. Results: The physical characteristics of flakes greenish-yellow, slightly fragrant aroma typical of flakes, rather unpleasant taste typical of Moringa leaves and a slightly crunchy texture. Organoleptic characteristics the color of flakes with moringa leaf powder 5%, the aroma of the flakes without addition moringa leaf powder, the flavour of flakes with additions moringa leaf powder 5% and the texture of flakes with additions moringa leaf powder 7,5% most prefered panelist and high levels calcium of flakes with additions 10% moringa leaf powder. Conclusion: There is a difference variations addition of moringa leaf powder on physical, organoleptic characteristic (color) and the level of calcium flakes.Flakes with the addition of 5% moringa leaf powder is the most prefered panelist.   Keywords:Moringa Leaf Flour, Flakes, Physical characteristic, organoleptic, Calcium

Effect of phorbol myristate acetate on secretion of parathyroid hormone

1988 ◽  
Vol 254 (1) ◽  
pp. E63-E70 ◽  
Author(s):  
J. J. Morrissey
Keyword(s):  
Protein Kinase C ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Membrane Fraction ◽  
Hormone Secretion ◽  
Myristate Acetate ◽  
Kinase C ◽  
Low Calcium ◽  
Protein Kinase C Activity ◽  
High Calcium

The influence of phorbol myristate acetate (PMA), an activator of protein kinase c, on the secretion of parathyroid hormone from collagenase-dispersed bovine parathyroid cells was tested. The cells were incubated at low (0.5 mM) or high (2.0 mM) concentrations of calcium in the medium, and the hormone secreted into the medium was measured by a radioimmunoassay that recognizes both intact and C-terminal fragments of hormone. At low calcium, the secretory rate averaged 32 +/- 3.8 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA did not affect secretion. At high calcium there was a significant suppression of secretion by 38% to 19.8 +/- 3 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA significantly stimulated hormone secretion to 35.8 +/- 8 ng.h-1.(10(5) cells)-1, a rate indistinguishable from low calcium. This stimulatory effect of PMA at high calcium was seen at PMA concentrations as low as 1.6 nM, did not occur with a biologically inactive 4 alpha-isomer of phorbol ester, and was independent of changes in cellular adenosine 3',5'-cyclic monophosphate levels. Examination of 32P-labeled phosphoproteins by two-dimensional gel electrophoresis revealed acidic proteins of approximately 20,000 and 100,000 Da that were phosphorylated at low and high calcium + 1.6 microM PMA but not at high calcium alone. The protein kinase c activity associated with the membrane fraction of parathyroid cells significantly decreased 40% when the cells were incubated at high vs. low calcium. The data suggest that calcium may regulate parathyroid hormone secretion through changes in protein kinase c activity of the membrane fraction of the cell and protein phosphorylation.

scholarly journals Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools

1979 ◽  
Vol 83 (3) ◽  
pp. 521-528 ◽  
Author(s):  
JJ Morrissey ◽  
DV Cohn
Keyword(s):  
Cyclic Amp ◽  
Half Life ◽  
Calcium Concentration ◽  
Hormone Secretion ◽  
Ionized Calcium ◽  
Dibutyryl Cyclic Amp ◽  
Low Calcium ◽  
High Calcium ◽  
Parathormone Secretion

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.

Variants of the Circle of Willis as seen on magnetic resonance angiography and carotid siphon calcifications in community-dwelling older adults

2021 ◽  
pp. 197140092110428
Author(s):  
Oscar H Del Brutto ◽  
Bettsy Y. Recalde ◽  
Robertino M Mera
Keyword(s):  
Older Adults ◽  
Magnetic Resonance ◽  
Calcium Content ◽  
Circle Of Willis ◽  
Community Dwelling ◽  
Anatomical Variants ◽  
Study Results ◽  
High Calcium ◽  
Independent Association ◽  
Community Dwelling Older Adults

Background and purpose Information on the association between anatomical variants of the Circle of Willis (CoW) and intracranial atherosclerotic disease (ICAD) is limited and results are controversial. In this population-based study, we aimed to assess whether an incomplete CoW is associated with high calcium content in carotid siphons (a reliable biomarker of ICAD) in community-dwelling older adults of Amerindian ancestry. Methods Individuals aged ≥60 years enrolled in the Three Villages Study received a head computed tomography (CT) and magnetic resonance angiogram (MRA) of intracranial vessels. The CoW was classified in complete or incomplete according to the presence or absence of one A1 segment of the anterior cerebral artery or one or both P1 segments of posterior cerebral arteries. Calcium content in carotid siphons was rated as low or high. A multivariate logistic model was fitted to assess the independent association between incompleteness of the CoW and high calcium content in carotid siphons, after adjusting for demographics and cardiovascular risk factors. Results A total of 581 individuals were enrolled (mean age: 71 ± 8.4 years; 57% women). MRA revealed an incomplete CoW in 227 (39%) individuals, and high-resolution CT disclosed high calcium content in carotid siphons in 185 (32%). A risk factor logistic regression model showed no independent association between incompleteness of the CoW and high calcium content in carotid siphons (odds ratio: 0.91; 95% confidence interval: 0.62–1.34; p = 0.631). Conclusion Study results disclosed no association between anatomical variants of the CoW and the presence of high calcium content in carotid siphons.

Electrokinetic Phenomena and Surface Characteristics of Fly Ash Particles

1984 ◽  
Vol 43 ◽  
Author(s):  
R. I. A. Malek ◽  
D. M. Roy
Keyword(s):  
Fly Ash ◽  
Surface Characteristics ◽  
Ionic Species ◽  
Point Of Zero Charge ◽  
Fly Ashes ◽  
Electrokinetic Phenomena ◽  
Zeta Potentials ◽  
Low Calcium ◽  
High Calcium

AbstractThe zeta-potentials of two fly ashes were studied (high-calcium and low-calcium). It was found that they possess a point of charge reversal at pH = 10.5 to 12. The point of zero charge (low-calcium fly ash) was found to be at pH = 5. Furthermore, it shifted to more acidic values after the fly ash is aged in several calcium-containing solutions. The surficial changes that could happen when mixing fly ashes with cement and concrete were further evaluated by aging fly ashes in different solutions: Ca(OH)2, CaSO4·2H2O, NaOH and water solutions. Information from analyses for different ionic species in the solutions and characterization of the solid residues (XRD and SEM) was used in tentative explanations for the different behavior of the two types of fly ash in cementitious mixtures and concrete.

Extraction and Atomic Absorption Analysis of Lead in Plant and Animal Products

1969 ◽  
Vol 52 (4) ◽  
pp. 708-714 ◽  
Author(s):  
William L Hoover ◽  
John C Reagor ◽  
Julianne C Garner
Keyword(s):  
Atomic Absorption ◽  
Ammonium Carbonate ◽  
Calcium Content ◽  
Atomic Absorption Spectrophotometry ◽  
Animal Tissue ◽  
Good Recovery ◽  
Animal Products ◽  
Absorption Spectrophotometry ◽  
Strontium Sulfate ◽  
High Calcium

Abstract Samples of plant or animal tissue are digested in a mixture of HNO3, H2SO4, and HClO4. Lead released in the digestion is entrained with strontium sulfate. The sulfate precipitate is separated from the digest and then converted to the carbonate by agitation with ammonium carbonate solution. The carbonate precipitate is dissolved in 1N HNO3, and lead is determined by atomic absorption spectrophotometry. Good recovery of lead (100 ± 3%) was observed except in samples with high calcium content (> 1%). For the latter samples, good recoveries were obtained after separation of the calcium from the digested samples. Moderate quantities of the following elements do not interfere: Al, Fe, P, Sn, Ca, Bi, and Tl. Most elements are soluble as sulfates and, hence, do not interfere. The procedure is rugged. Dry samples containing from 0.5 ppm to 1% lead can be routinely analyzed.

Electrotonic and chemical effects on minimal gradient requirements for cardiac muscle

1962 ◽  
Vol 202 (2) ◽  
pp. 245-248 ◽  
Author(s):  
Junji Ushiyama ◽  
Chandler McC. Brooks
Keyword(s):  
Cardiac Muscle ◽  
Chemical Effects ◽  
Low Calcium ◽  
High Calcium ◽  
Minimal Gradient

The thresholds to rectangular pulses and the minimal gradient requirements for excitation of trabecular muscles from dog hearts were determined. Catelectrotonus lowered thresholds and shortened the minimal gradient or lambda (λ). Anelectrotonus raised thresholds and greatly prolonged lambda. Low calcium lowered threshold and increased lambda, whereas high calcium raised the threshold and shortened lambda. Quinidine and dinitrophenol had little effect on threshold but prolonged lambda. Cyanide also had little effect on threshold but shortened lambda. Urethan and cocaine slightly raised thresholds and shortened lambda. There is thus no correlation between changes in threshold and changes in minimal gradient (λ). The significance of lambda is not known.

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