Calcium Regulation in the Freshwater Mollusc Limnaea Stagnalis (L.) (Gastropoda: Pulmonata)

1971 ◽  
Vol 54 (3) ◽  
pp. 609-620 ◽  
Author(s):  
PETER GREENAWAY
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Calcium Regulation ◽  
Fresh Tissue ◽  
Blood Calcium ◽  
Freshwater Mollusc ◽  
Net Uptake ◽  
Tissue Calcium ◽  
Limnaea Stagnalis ◽  
Calcium Loss

1. Three major calcium compartments have been identified in L. stagnalis: the shell, the blood and the fresh tissues. 2. The distribution of 45Ca, absorbed from the medium, in the tissues of L. stagnalis has been studied. Absorbed calcium appears first in the blood and then in the shell and other tissues. 3. 30% of the total fresh tissue calcium and about 20% of mantle calcium exchanges with blood calcium. A continual exchange between shell and blood calcium occurs. 4. During net calcium loss from L. stagnalis a net movement of calcium from shell to blood occurs at a rate similar to the rate of net loss. During net calcium uptake, the reverse movement from blood to shell at a rate similar to the rate of net uptake occurs. 5. A simple mechanism which might account for the control of blood calcium concentration has been proposed.

scholarly journals Calcium Regulation in the Freshwater Mollusc, Limnaea Stagnalis (L.) (Gastropoda: Pulmonata)

1971 ◽  
Vol 54 (1) ◽  
pp. 199-214 ◽  
Author(s):  
PETER GREENAWAY
Keyword(s):  
Calcium Concentration ◽  
Calcium Regulation ◽  
Calcium Balance ◽  
Calcium Depletion ◽  
Uptake Mechanism ◽  
Freshwater Mollusc ◽  
Net Uptake ◽  
Limnaea Stagnalis ◽  
Sodium Regulation ◽  
Linear Manner

1. Calcium regulation in normal and calcium-depleted snails has been investigated. 2. L. stagnalis has an uptake mechanism with a high affinity for calcium ions and shows a positive calcium balance in media containing more than 0.062 mM Ca/l. 3. Influx and net uptake of calcium are related to external calcium concentration in a non-linear manner. The uptake mechanism is half-saturated and near-saturated in external media containing 0.3 and 1.0-1.5 mM Ca/l respectively. 4. Calcium uptake from external concentrations of less than 0.5 mM Ca/l is against a small electrochemical gradient whereas from external concentrations greater than 0.5 mM Ca/l there is no adverse gradient. 5. Calcium depletion does not significantly alter the normal influx or net uptake rate of calcium from 1.0 mM Ca/l. 6. The calcium concentration in the blood remains constant during net uptake from, and net loss to, the medium. 7. A comparison is made between the mechanisms of sodium regulation and calcium regulation in L. stagnalis.

Calcium Regulation in the Freshwater Crayfish Austropotamobius Pallipes (Lereboullet)

1972 ◽  
Vol 57 (2) ◽  
pp. 471-487
Author(s):  
PETET GREENAWAY
Keyword(s):  
Active Transport ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Calcium Regulation ◽  
Freshwater Crayfish ◽  
Calcium Balance ◽  
Electrochemical Gradient ◽  
Austropotamobius Pallipes ◽  
Calcium Loss ◽  
Normal Calcium

1. Calcium regulation in normal and in calcium-depleted specimens of Austropotamobius pallipes in the intermoult condition has been investigated. 2. Calcium turnover was very low and the normal calcium balance was negative for much of the winter intermoult stage. 3. Calcium uptake was against a small electrochemical gradient, at least part of the influx occurring by active transport. 4. Most of the calcium loss occurred across the gills, and the urine contribution was small. 5. Calcium-depleted animals showed only a small fall in haemolymph calcium concentration and calcium uptake was not significantly increased by depletion.

scholarly journals Calcium transport in intact human erthrocytes.

1976 ◽  
Vol 68 (1) ◽  
pp. 29-41 ◽  
Author(s):  
G Plishker ◽  
H J Gitelman
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Calcium Content ◽  
Ion Composition ◽  
Inhibitory Effects ◽  
Sodium Potassium ◽  
Tetramethylammonium Chloride ◽  
Low Concentrations ◽  
Net Uptake ◽  
External Calcium

Intact human erythrocytes can be readily loaded with calcium by incubation in hypersomotic media at alkaline pH. Erythrocyte calcium content increases from 15-20 to 120-150 nmol/g hemoglobin after incubation for 2 h at 20 degree C in a 400 mosmol/kg, pH 7.8 solution containing 100 mM sodium chloride, 90 mM tetramethylammonium chloride, 1 mM potassium chloride, and 10 mM calcium chloride. Calcium uptake is a time-dependent process that is associated with an augmented efflux of potassium. The ATP content in these cells remains at more than 60% of normal and is not affected by calcium. Calcium uptake is influenced by the cationic composition of the external media. The response to potassium is diphasic. With increasing potassium concentrations, the net accumulation of calcium initially increases, becoming maximal at 1 mM potassium, then diminishes, falling below basal levels at concentrations above 3 mM potassium. Ouabain inhibits the stimulatory effect of low concentrations of potassium. The inhibitory effects of higher concentrations of potassium are ouabain insensitive and independent of the external calcium concentration. Sodium also inhibits calcium uptake but this inhibition can be modified by altering the external concentration of calcium. The effux of calcium from loaded erythrocytes is not significantly altered by changes in osmolality, medium ion composition, or ouabain. It is concluded that hypertonicity increases the net uptake of calcium by increasing the influx of calcium and that some part of the sodium potassium transport system is involved in this influx process.

scholarly journals Short communication: Test of the relationship between prepartum milk leakage and blood calcium concentration in Holstein cows—An observational study

2018 ◽  
Vol 101 (4) ◽  
pp. 3579-3582
Author(s):  
Ehsan Mahjoubi ◽  
Davood Zahmatkesh ◽  
Mehdi Hossein-Yazdi ◽  
Mohammad Hadi Khabbazan ◽  
Mohammad Reza Samadian
Keyword(s):  
Observational Study ◽  
Calcium Concentration ◽  
Short Communication ◽  
Holstein Cows ◽  
Blood Calcium ◽  
The Relationship

On-farm use of a water hardness test kit to assess total blood calcium level in dairy cattle

2020 ◽  
Vol 87 (1) ◽  
pp. 56-59
Author(s):  
Filippo Fiore ◽  
Raffaella Cocco ◽  
Daniele Musina ◽  
Nicoletta Spissu
Keyword(s):  
Dairy Cattle ◽  
Calcium Concentration ◽  
Water Hardness ◽  
Hardness Test ◽  
Total Serum ◽  
Total Blood ◽  
Predictive Values ◽  
Blood Calcium ◽  
Test Kit ◽  
On Farm

AbstractIn this Research Communication we report the measurement of total blood calcium concentration with a water hardness test kit (WHTK) in dairy cattle and compare the results to a reference method. The study was carried out on 107 Holstein Friesian cows from three commercial dairy farms in Sardinia (Italy). Blood samples were collected ≤7 d from calving and total serum calcium concentration was determined using a biochemical analyzer and a WHTK. The relationship between the laboratory results and the WHTK results was investigated using Spearman's rank correlation test and simple linear regression was determined. Sensitivity, specificity, negative and positive predictive values, intra and inter-assay coefficient of variation were also calculated. The test values were highly correlated with the laboratory values (R2 = 0.72, P < 0.001). Sensitivity and specificity were respectively 88 and 83% for the WHTK and intra and inter-assay coefficients of variation were 7.3 and 11.3% respectively. The WHTK was identified as a potential on-farm tool for monitoring early postpartum Ca concentrations at herd level.

Invariance of Stoichiometry of the Sarcoplasmic Reticulum Calcium Pump at Physiological Calcium Concentrations – a Reevaluation

1985 ◽  
Vol 40 (7-8) ◽  
pp. 571-575 ◽  
Author(s):  
Wilhelm Hasselbach ◽  
Andrea Migala
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Level ◽  
Calcium Concentration ◽  
Calcium Uptake ◽  
Atp Hydrolysis ◽  
Calcium Pump ◽  
Oxalate Precipitation ◽  
Sarcoplasmic Reticulum Calcium ◽  
Internal Calcium ◽  
External Calcium

Abstract The decline of the transport ratio of the sarcoplasmic calcium pump observed in a recent study (A. results from the retardation of calcium oxalate precipitation at low calcium/protein ratios. The prevailing high internal calcium level supports a rapid calcium backflux and a compensatory ATP hydrolysis during net calcium uptake which reduces the transport ratio. Yet, the determined calcium back­ flux does not fully account for the decline of the transport ratio. A supposed modulation of the stoichiometry of the pump by external calcium (0.1 μм) is at variance with results of previous studies showing a constant transport ratio of two in the same calcium concentration range.

The Effect of Calcium Concentration on Calcium Uptake by Bone Cells Treated with Thyrocalcitonin (TCT) Hormone

Endocrinology ◽  
1973 ◽  
Vol 92 (2) ◽  
pp. 550-555 ◽  
Author(s):  
ARIEH HARELL ◽  
ITZHAK BINDERMAN ◽  
GIDEON A. RODAN
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Bone Cells

Secretion of calcium by rat submandibular gland

1959 ◽  
Vol 196 (3) ◽  
pp. 645-648 ◽  
Author(s):  
Robert H. Dreisbach
Keyword(s):  
Submandibular Gland ◽  
Calcium Concentration ◽  
Total Serum ◽  
Transient Phase ◽  
Secretory Rate ◽  
Total Serum Calcium ◽  
The Mean ◽  
Rat Submandibular Gland ◽  
Calcium Loss ◽  
Mean Concentration

The mean concentration of calcium in rat submandibular gland saliva after maximal pilocarpine stimulation was initially 3.2 µEq/gm and gradually fell during the 1st hour to 0.93 µEq/gm. The final concentration was approximately 30% of the concentration of calcium in the serum ultrafiltrate whether the total serum calcium was normal or elevated threefold by the infusion of calcium chloride. At the end of the transient phase, the gland calcium concentration was from 28 to 57% less than the initial gland concentration depending upon the type of anesthesia used. The calcium loss from the gland correlated well with the excess calcium secreted in the saliva during the transient phase. After the initial transient phase was ended, the saliva calcium concentration bore an inverse relationship to the secretory rate and was directly proportional to the serum ultrafiltrate calcium concentration.

Solution calcium concentration and application date effects on pod calcium uptake and distribution in florunner and tifton‐8 peanut

1989 ◽  
Vol 12 (1) ◽  
pp. 37-52 ◽  
Author(s):  
Halina Smal ◽  
Craig S. Kvien ◽  
Malcolm E. Sumner ◽  
Alexander S. Csinos
Keyword(s):  
Calcium Concentration ◽  
Calcium Uptake ◽  
Application Date

905 Roles of the ventromedial nucleus of the hypothalamus on blood calcium regulation

1993 ◽  
Vol 18 ◽  
pp. S96
Author(s):  
Shuji Aou ◽  
Katsuhiko Shiramine ◽  
Nobuyoshi Nozawa ◽  
Takashi Matsumoto ◽  
Tetsuro Hori
Keyword(s):  
Calcium Regulation ◽  
Ventromedial Nucleus ◽  
Blood Calcium
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