EFFECTS OF HYDROXYLATED DERIVATIVES OF VITAMIN D3 AND OF AQUEOUS EXTRACTS OF SOLANUM MALACOXYLON ON THE ABSORPTION OF CALCIUM, PHOSPHATE, SODIUM, POTASSIUM AND WATER FROM THE JEJUNUM OF PIGS

1979 ◽  
Vol 82 (3) ◽  
pp. 417-424 ◽  
Author(s):  
J. FOX ◽  
A. D. CARE
Keyword(s):  
Vitamin D ◽  
Calcium Phosphate ◽  
Time Course ◽  
Intestinal Loop ◽  
Delayed Response ◽  
Aqueous Extracts ◽  
Sodium Potassium ◽  
Solanum Malacoxylon ◽  
Derivatives Of ◽  
Sodium And Potassium

The effects of hydroxylated derivatives of vitamin D3 and aqueous extracts of Solanum malacoxylon on the intestinal absorption of calcium, phosphate, sodium, potassium and water have been studied in unstressed vitamin D-replete pigs each of which was surgically prepared beforehand with a Thirty–Vella loop of jejunum. The addition, for six 1 h periods of perfusion, of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) or 1α-hydroxycholecalciferol at similar concentrations (3·6–3·75 pmol/ml) to the solution used to perfuse the intestinal loop caused a rapid increase in the absorption of calcium but increased the absorption of phosphate only after a delay of at least 12 h. The absorption of both calcium and phosphate reached a maximum on the day following the addition of the vitamin D derivative to the perfusate. The addition of 25-hydroxycholecalciferol (25-(OH)D3) at a concentration of 3·75 pmol/ml was without effect on absorption except for a small increase in the absorption of phosphate on the following day. However, at higher concentrations (> 250 pmol 25-(OH)D3/ml) the absorptions of calcium and phosphate were both increased rapidly. 24,25-Dihydroxycholecalciferol was without effect on absorption at the concentration tested (3·6 pmol/ml). Aqueous extracts (1%) of the leaf of S. malacoxylon showed similar effects on absorption to those of 1,25-(OH)2D3. However, there was one point of difference; the absorption of phosphate was stimulated with a similar time course to that of calcium in contrast to its delayed response to 1,25-(OH)2D3. The absorption rates of water, sodium and potassium were not consistently affected by 1,25-(OH)2D3 or S. malacoxylon. However, the major effects of these derivatives were usually seen on the day following the day of addition to the perfusate. In contrast, 25-(OH)D3 at high concentrations had a marked effect on the absorption of water, sodium and potassium on the day of addition.

Bone resorption and mineral excretion in rats during spaceflight

1983 ◽  
Vol 244 (3) ◽  
pp. R327-R331 ◽  
Author(s):  
C. E. Cann ◽  
R. R. Adachi
Keyword(s):  
Neutron Activation Analysis ◽  
Bone Resorption ◽  
Time Course ◽  
Large Change ◽  
Sodium Potassium ◽  
Total Body Calcium ◽  
Mineral Excretion ◽  
Synchronous Control ◽  
Total Body ◽  
Sodium And Potassium

Bone resorption was measured directly in flight and synchronous control rats during COSMOS 1129. Continuous tracer administration techniques were used, with replacement of dietary calcium with isotopically enriched 40Ca and measurement by neutron activation analysis of the 48Ca released by the skeleton. There is no large change in bone resorption in rats at the end of 20 days of spaceflight as has been found for bone formation. Based on the time course of changes, the measured 20–25% decrease in resorption is probably secondary to a decrease in total body calcium turnover. The excretion of sodium, potassium, and zinc all increase during flight, sodium and potassium to a level four to five times control values.

scholarly journals Time Course of ECG Depolarization and Repolarization Changes during Ischemia in PTCA Recordings

2004 ◽  
Vol 43 (01) ◽  
pp. 43-46 ◽  
Author(s):  
J. García ◽  
G. Wagner ◽  
R. Bailón ◽  
L. Sörnmo ◽  
P. Laguna ◽  
...  
Keyword(s):  
Time Course ◽  
Wave Amplitude ◽  
Temporal Evolution ◽  
Delayed Response ◽  
S Wave ◽  
Ecg Changes ◽  
T Complex ◽  
Karhunen Loeve Transform ◽  
Low Amplitude ◽  
Electrocardiogram Ecg

Summary Objectives: In this work we studied the temporal evolution of changes in the electrocardiogram (ECG) as a consequence of the induced ischemia during prolonged coronary angioplasty, comparing the time course of indexes reflecting depolarization and those reflecting repolarization. Methods: We considered both local (measured at specific points of the ECG) and global (obtained from the Karhunen-Loève transform) indexes. In particular, the evolution of Q, R and S wave amplitudes during ischemia was analyzed with respect to classical indexes such as ST level. As a measurement of sensitivity we used an Ischemic Changes Sensor (ICS), which reflects the capacity of an index to detect changes in the ECG. Results: The results showed that, in leads with low-amplitude ST-T complexes, the S wave amplitude was more sensitive in detecting ischemia than was the commonly used index ST60. It was found that in such leads the S wave amplitude initially exhibited a delayed response to ischemia when compared to ST60, but its performance was better from the second minute of occlusion. The global indexes describing the ST-T complex were, in terms of the ICS, superior to the S wave amplitude for ischemia detection. Conclusions: Ischemic ECG changes occur both at repolarization and depolarization, with alterations in the depolarization period appearing later in time. Local indexes are less sensitive to ischemia than global ones.

scholarly journals Efficacy of weekly administration of cholecalciferol on parathyroid hormone in stable kidney-transplanted patients with CKD stage 1–3

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Stefania Sella ◽  
Luciana Bonfante ◽  
Maria Fusaro ◽  
Flavia Neri ◽  
Mario Plebani ◽  
...  
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Calcium Phosphate ◽  
Serum Calcium ◽  
Chronic Kidney Disease Stage ◽  
Serum Vitamin ◽  
Disease Stage ◽  
Weekly Administration ◽  
Ckd Stage ◽  
Stage 1

AbstractObjectivesKidney transplant (KTx) recipients frequently have deficient or insufficient levels of serum vitamin D. Few studies have investigated the effect of cholecalciferol in these patients. We evaluated the efficacy of weekly cholecalciferol administration on parathyroid hormone (PTH) levels in stable KTx patients with chronic kidney disease stage 1–3.MethodsIn this retrospective cohort study, 48 stable KTx recipients (37 males, 11 females, aged 52 ± 11 years and 26 months post-transplantation) were treated weekly with oral cholecalciferol (7500–8750 IU) for 12 months and compared to 44 untreated age- and gender-matched recipients. Changes in levels of PTH, 25(OH) vitamin D (25[OH]D), serum calcium, phosphate, creatinine and estimated glomerular filtration rate (eGFR) were measured at baseline, 6 and 12 months.ResultsAt baseline, clinical characteristics were similar between treated and untreated patients. Considering the entire cohort, 87 (94.6%) were deficient in vitamin D and 64 (69.6%) had PTH ≥130 pg/mL. Serum calcium, phosphate, creatinine and eGFR did not differ between groups over the follow-up period. However, 25(OH)D levels were significantly higher at both 6 (63.5 vs. 30.3 nmol/L, p < 0.001) and 12 months (69.4 vs. 30 nmol/L, p < 0.001) in treated vs. untreated patients, corresponding with a significant reduction in PTH at both 6 (112 vs. 161 pg/mL) and 12 months (109 vs. 154 pg/mL) in treated vs. untreated patients, respectively (p < 0.001 for both).ConclusionsWeekly administration of cholecalciferol can significantly and stably reduce PTH levels, without any adverse effects on serum calcium and renal function.

scholarly journals A phosphate and calcium-enriched diet promotes progression of 5/6-nephrectomy-induced chronic kidney disease in C57BL/6 mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Radloff ◽  
N. Latic ◽  
U. Pfeiffenberger ◽  
C. Schüler ◽  
S. Tangermann ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Calcium Phosphate ◽  
Kidney Disease ◽  
Renal Fibrosis ◽  
Time Course ◽  
Bone Mineralization ◽  
Fibroblast Growth Factor 23 ◽  
Functional Decline ◽  
Left Ventricular ◽  
Normal Diet

AbstractC57BL/6 mice are known to be rather resistant to the induction of experimental chronic kidney disease (CKD) by 5/6-nephrectomy (5/6-Nx). Here, we sought to characterize the development of CKD and its cardiac and skeletal sequelae during the first three months after 5/6-Nx in C57BL/6 mice fed a calcium- and phosphate enriched diet (CPD) with a balanced calcium/phosphate ratio. 5/6-NX mice on CPD showed increased renal fibrosis and a more pronounced decrease in glomerular filtration rate when compared to 5/6-Nx mice on normal diet (ND). Interestingly, despite comparable levels of serum calcium, phosphate, and parathyroid hormone (PTH), circulating intact fibroblast growth factor-23 (FGF23) was 5 times higher in 5/6-Nx mice on CPD, relative to 5/6-Nx mice on ND. A time course experiment revealed that 5/6-Nx mice on CPD developed progressive renal functional decline, renal fibrosis, cortical bone loss, impaired bone mineralization as well as hypertension, but not left ventricular hypertrophy. Collectively, our data show that the resistance of C57BL/6 mice to 5/6-Nx can be partially overcome by feeding the CPD, and that the CPD induces a profound, PTH-independent increase in FGF23 in 5/6-Nx mice, making it an interesting tool to assess the pathophysiological significance of FGF23 in CKD.

scholarly journals Changes in the Membrane Permeability of Frog's Sartorius Muscle Fibers in Ca-Free EDTA Solution

1963 ◽  
Vol 47 (2) ◽  
pp. 379-392 ◽  
Author(s):  
H. Kimizuka ◽  
K. Koketsu
Keyword(s):  
Membrane Permeability ◽  
Chloride Content ◽  
Chloride Ions ◽  
Sartorius Muscle ◽  
Constant Field ◽  
Sodium Influx ◽  
Sodium Potassium ◽  
Edta Solution ◽  
Frog Sartorius ◽  
Sodium And Potassium

The changes in the membrane permeability to sodium, potassium, and chloride ions as well as the changes in the intracellular concentration of these ions were studied on frog sartorius muscles in Ca-free EDTA solution. It was found that the rate constants for potassium and chloride efflux became almost constant within 10 minutes in the absence of external calcium ions, that for potassium increasing to 1.5 to 2 times normal and that for chloride decreasing about one-half. The sodium influx in Ca-free EDTA solution, between 30 and 40 minutes, was about 4 times that in Ringer's solution. The intracellular sodium and potassium contents did not change appreciably but the intracellular chloride content had increased to about 4 times normal after 40 minutes. By applying the constant field theory to these results, it was concluded that (a) PCl did not change appreciably whereas PK decreased to a level that, in the interval between 10 and 40 minutes, was about one-half normal, (b) PNa increased until between 30 and 40 minutes it was about 8 times normal. The low value of the membrane potential between 30 and 40 minutes was explained in terms of the changes in the membrane permeability and the intracellular ion concentrations. The mechanism for membrane depolarization in this solution was briefly discussed.

Effects of acute and chronic treatment with glucocorticoids on the intestinal absorption of calcium and phosphate and on plasma 1,25-dihydroxyvitamin D levels in pigs

1985 ◽  
Vol 69 (5) ◽  
pp. 553-559 ◽  
Author(s):  
John Fox ◽  
Richardus Ross ◽  
Anthony D. Care
Keyword(s):  
Intestinal Absorption ◽  
Plasma Levels ◽  
Time Course ◽  
Chronic Treatment ◽  
Intestinal Loop ◽  
Phosphate Absorption ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Young Pigs ◽  
Proximal Small Intestine

1. We have used young pigs, each prepared surgically with a Thiry-Vella loop of proximal small intestine, to study the time course of changes in the intestinal absorption of calcium, phosphate, sodium, glucose and water and on the plasma levels of 1,25-dihydroxyvitamin D after treatment of the animals with glucocorticoids. 2. Perfusion of the intestinal loop for 6 h with a solution containing hydrocortisone or betamethasone was without effect on the absorption of calcium or phosphate. 3. The oral administration of betamethasone stimulated the absorption of calcium and phosphate by 15–20% for 2–3 days before the trend was reversed and absorption was progressively reduced. 4. Chronic treatment with betamethasone inhibited only the active component of calcium and phosphate absorption. 5. Treatment with betamethasone was associated with a sustained 25–50% increase, to a maximum by 2 days, in the absorption of sodium, glucose and water. 6. Plasma levels of 1,25-dihydroxyvitamin D were reduced within 2 days of the start of treatment and reached a minimum (40–50% decrease) in 4–6 days. 7. We conclude that the initial stimulation of calcium and phosphate absorption is caused by the increased absorption of water. The long-term decrease in absorption may not be caused solely by the decreased circulating levels of 1,25-dihydroxyvitamin D since absorption continued to fall for several weeks after 1,25-dihydroxyvitamin D levels had reached a minimum.

scholarly journals Assessment of Biochemical and Densitometric Markers of Calcium-Phosphate Metabolism in the Groups of Patients with Multiple Sclerosis Selected due to the Serum Level of Vitamin D3

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Natalia Niedziela ◽  
Krystyna Pierzchała ◽  
Jolanta Zalejska-Fiolka ◽  
Jacek T. Niedziela ◽  
Ewa Romuk ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Vitamin D ◽  
Calcium Phosphate ◽  
Serum Level ◽  
Clinical Stage ◽  
Phosphate Metabolism ◽  
Disability Status ◽  
Relapsing Remitting ◽  
Relapsing Remitting Multiple Sclerosis ◽  
Calcium Phosphate Metabolism

Background. In addition to the widely known effect of vitamin D3 (vitD3) on the skeleton, its role in the regulation of the immune response was also confirmed. Aim. The assessment of biochemical and densitometric markers of calcium-phosphate metabolism in the groups of patients with relapsing-remitting multiple sclerosis (RRMS) selected due to the serum level of vitamin D3. Methods. The concentrations of biochemical markers and indices of lumbar spine bone densitometry (DXA) were determined in 82 patients divided into vitamin D3 deficiency (VitDd), insufficiency (VitDi), and normal vitamin D3 level (VitDn) subgroups. Results. The highest level of the parathyroid hormone (PTH) and the highest prevalence of hypophosphatemia and osteopenia were demonstrated in VitDd group compared to VitDi and VitDn. However, in VitDd, VitDi, and VitDn subgroups no significant differences were observed in the levels of alkaline phosphatase (ALP) and ionized calcium (Ca2+) and in DXA indices. A negative correlation was observed between the level of vitamin D3 and the Expanded Disability Status Scale (EDSS) in the whole MS group. The subgroups were significantly different with respect to the EDSS scores and the frequency of complaints related to walking according to the EQ-5D. Conclusions. It is necessary to assess calcium-phosphate metabolism and supplementation of vitamin D3 in RRMS patients. The higher the clinical stage of the disease assessed with the EDSS, the lower the level of vitamin D3 in blood serum. Subjectively reported complaints related to difficulties with walking were reflected in the EDSS in VitDd patients.

Cardiovascular and renal effects of hypoxia in conscious carotid body-denervated rats

1993 ◽  
Vol 74 (6) ◽  
pp. 2795-2800 ◽  
Author(s):  
R. Behm ◽  
H. Mewes ◽  
W. H. DeMuinck Keizer ◽  
T. Unger ◽  
R. Rettig
Keyword(s):  
Carotid Body ◽  
Normobaric Hypoxia ◽  
Sodium Potassium ◽  
Water Excretion ◽  
Excretory Function ◽  
Arterial Blood ◽  
Peripheral Arterial ◽  
Renal Responses ◽  
Arterial Po2 ◽  
Sodium And Potassium

The contribution of peripheral arterial chemoreceptors to cardiovascular and renal responses to acute hypocapnic hypoxia is currently not well understood. We compared the effects of normobaric hypoxia on mean arterial blood pressure (MABP), heart rate, glomerular filtration rate (GFR), renal blood flow (RBF), and renal volume and electrolyte excretion in conscious unilaterally nephrectomized carotid body-denervated (n = 10) and sham-operated (n = 10) control rats. Thirty minutes of normobaric hypoxia (12.5% O2) resulted in significant reductions in arterial PO2 and PCO2 as well as decreases in MABP, GFR, RBF, and renal sodium, potassium, and water excretion. These effects occurred more rapidly and/or were significantly more pronounced in carotid body-denervated than in sham-operated rats. These data indicate that moderate acute hypocapnic hypoxia has profound effects on systemic and renal hemodynamics as well as on renal excretory function in conscious rats. We conclude that stimulation of the peripheral arterial chemoreceptors can partially offset the hypoxia-induced decreases in MABP, RBF, GFR, urine flow, and urinary sodium and potassium excretion, thereby helping to maintain cardiovascular as well as fluid and electrolyte homeostasis.

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