scholarly journals Effects of lα-hydroxylated metabolites of cholecalciferol on intestinal radiocalcium absorption in goats

1984 ◽  
Vol 51 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Knut Hove
Keyword(s):  
Fatty Acid ◽  
Oral Administration ◽  
Intestinal Absorption ◽  
Plasma Concentrations ◽  
Rumen Degradation ◽  
Hydroxylated Metabolites ◽  
Naturally Occurring ◽  
Isotope Technique ◽  
Dose Dependent ◽  
Double Isotope

1. Intestinal absorption of 47Ca was measured by a double-isotope technique in goats treated with 1, 5 or 25 μg of 1,25-dihydroxycholecalciferol (1,25(OH)2D3). The effects of giving 1,25(OH)2D3 by intravenous (iv) infusion for 30–36 h were compared at each dose level with the effects obtained by oral administration of 1,25(OH)2D3 either in ethanol or protected against rumen degradation in fatty acid pellets.2. Dose-dependent increments in absorption followed the treatments, with a doubling of absorption at the 1 μg dose and three- to fivefold increases with the 5 and 25 μg doses. 47Ca absorption was equally stimulated 2 and 6 d after treatment but had returned to pretreatment levels 12–14 d after treatment.3. Intravenous and protected oral administration of 1,25(OH)2D3 stimulated 47Ca absorption to the same extent, in spite of two- to fivefold higher plasma concentrations of 1,25(OH)2D3 after iv treatment. Somewhat lower increments in 47Ca absorption were seen using ethanol as the vehicle for oral administration.4. The naturally occurring metabolites 1,24(R),25-trihydroxycholecalciferol and 1,25(S),26-trihydroxy-cholecalciferol had only one-tenth to one-fifteenth the potency of 1,25(OH)2D3 in stimulating 47Ca absorption, while synthetic lα-hydroxycholecalciferol appeared to be twice as effective as 1,25(OH)2D3 when tested at a high (10μg) dose.

REVERSAL OF BETAMETHASONE-INDUCED INHIBITION OF INTESTINAL CALCIUM ABSORPTION BY 1α-HYDROXYCHOLECALCIFEROL

1978 ◽  
Vol 78 (2) ◽  
pp. 187-194 ◽  
Author(s):  
J. FOX ◽  
A. D. CARE ◽  
D. H. MARSHALL
Keyword(s):  
Absorption Coefficient ◽  
Oral Administration ◽  
Intestinal Absorption ◽  
Calcium Absorption ◽  
Mean Value ◽  
Intestinal Calcium Absorption ◽  
Control Value ◽  
Isotope Technique ◽  
Intravenous And Oral Administration ◽  
Double Isotope

SUMMARY The intestinal absorption of calcium has been studied in conscious, unstressed pigs, using a modification of the double isotope technique. The oral administration of betamethasone (1 mg/day) to four pigs (25–33 kg) for 4 weeks reduced the calcium absorption coefficient, calculated after the intravenous and oral administration of 47Ca2+, by a mean value of 66%. The oral administration of 1α-hydroxycholecalciferol (2 μg/day) in combination with betamethasone (1 mg/day) for a further 4 weeks returned the absorption coefficient to the control value.

scholarly journals Enhanced Intestinal Absorption and Pharmacokinetic Modulation of Berberine and Its Metabolites through the Inhibition of P-Glycoprotein and Intestinal Metabolism in Rats Using a Berberine Mixed Micelle Formulation

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 882
Author(s):  
Mihwa Kwon ◽  
Dong Yu Lim ◽  
Chul Haeng Lee ◽  
Ji-Hyeon Jeon ◽  
Min-Koo Choi ◽  
...  
Keyword(s):  
Oral Administration ◽  
Intestinal Absorption ◽  
Mixed Micelle ◽  
Oral Absorption ◽  
Plasma Concentrations ◽  
Tween 80 ◽  
Rat Plasma ◽  
Intestinal Metabolism ◽  
Plasma Exposure ◽  
P Glycoprotein

We aimed to develop a berberine formulation to enhance the intestinal absorption and plasma concentrations of berberine through the inhibition of P-glycoprotein (P-gp)-mediated efflux and the intestinal metabolism of berberine in rats. We used pluronic P85 (P85) and tween 80, which have the potential to inhibit P-gp and cytochrome P450s (i.e., CYP1A2, 2C9, 2C19, 2D6, and 3A4). A berberine-loaded mixed micelle formulation with ratios of berberine: P85: tween 80 of 1:5:0.5 (w/w/w) was developed. This berberine mixed micelle formulation had a mean size of 12 nm and increased the cellular accumulation of digoxin via P-gp inhibition. It also inhibited berberine metabolism in rat intestinal microsomes, without significant cytotoxicity, up to a berberine concentration of 100 μM. Next, we compared the pharmacokinetics of berberine and its major metabolites in rat plasma following the oral administration of the berberine formulation (50 mg/kg) in rats with the oral administration of berberine alone (50 mg/kg). The plasma exposure of berberine was significantly greater in rats administered the berberine formulation compared to rats administered only berberine, which could be attributed to the increased berberine absorption by inhibiting the P-gp-mediated berberine efflux and intestinal berberine metabolism by berberine formulation. In conclusion, we successfully prepared berberine mixed micelle formulation using P85 and tween 80 that has inhibitory potential for P-gp and CYPs (CYP2C19, 2D6, and 3A4) and increased the berberine plasma exposure. Therefore, a mixed micelle formulation strategy with P85 and tween 80 for drugs with high intestinal first-pass effects could be applied to increase the oral absorption and plasma concentrations of the drugs.

Calcium Metabolism in Children Suffering from Homozygous ß-Thalassaemia after Oral Administration of 47Ca

1976 ◽  
Vol 15 (02) ◽  
pp. 77-79 ◽  
Author(s):  
D. Liakakos ◽  
P. Ylachos ◽  
Ch. Anoussakis ◽  
C. Constantinides ◽  
I. Tsakalosos
Keyword(s):  
Oral Administration ◽  
Intestinal Absorption ◽  
Calcium Metabolism

SummaryThe study of calcium metabolism in ten thalassaemic children comperatively with controls after oral administration of 47Ca has shown diminished intestinal absorption. It is suggested that this finding is propably related in part with the pathogenesis of the osteoporosis in thalassaemia.

The Measurement of Heparin and Other Therapeutic Sufphated Polysaccharides in Plasma, Serum and Urine

1985 ◽  
Vol 54 (03) ◽  
pp. 630-634 ◽  
Author(s):  
J Dawes ◽  
C V Prowse ◽  
D D Pepper
Keyword(s):  
Biological Fluids ◽  
Anticoagulant Activity ◽  
Dose Range ◽  
Plasma Concentrations ◽  
Heparin Therapy ◽  
Competitive Binding Assay ◽  
First Order Kinetics ◽  
Activity Measurements ◽  
Heparin Activity ◽  
Dose Dependent

SummaryThe competitive binding assay described will specifically and accurately measure concentrations of administered heparin in biological fluids with a sensitivity of 60 ng ml-1. Neither endogenous glycosaminoglycans, nor plasma proteins such as ATIII and PF4 interfere in the assay. Semi-synthetic highly sulphated heparinoids and LMW heparin can also be measured. Using this assay heparin clearance followed simple first-order kinetics over the dose range 100-5,000 units, but the half-life was strongly dose-dependent. There was good correlation with heparin activity measurements by APTT and anti-Xa clotting assays. Plasma concentrations were measurable for at least 5 h following subcutaneous injection of 10,000 units of heparin. Excretion in the urine could be followed after all but the lowest intravenous dose. This assay, used in conjunction with measurements of heparin anticoagulant activity, will be valuable in the elucidation of mechanisms of action of heparin and the heparinoids, and in the assessment and management of problems related to heparin therapy.

STUDIES ON THYROIDAL COLLOID PINOCYTOSIS USING A DOUBLE ISOTOPE TECHNIQUE

1972 ◽  
Vol 70 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Mario A. Pisarev ◽  
Noe Altschuler ◽  
Leslie J. DeGroot
Keyword(s):  
Acid Phosphatase ◽  
Thyroid Hormone ◽  
Trichloroacetic Acid ◽  
Specific Activity ◽  
Acid Precipitation ◽  
Solvent System ◽  
Blood Stream ◽  
Radioactive Materials ◽  
Isotope Technique ◽  
Double Isotope

ABSTRACT The process of secretion of the thyroid hormone involves several steps: pinocytosis of thyroglobulin, fusion of the colloid droplets with the lysosomes, digestion of thyroglobulin by a cathepsin, dehalogenation of tyrosines and release of thyronines into the blood stream. The present paper describes a double isotope technique for studying the first two steps. Thyrotrophin (TSH) administration to rats increased the radioactivity present in all fractions, specially in the 15 000 × g pellet. When the subcellular distribution of acid phosphatase was determined, the highest specific activity was found in this fraction, thus indicating the presence of lysosomes. The content of radioactive materials in the 15 000 × g pellet was analyzed by trichloroacetic acid precipitation and by ascending paper chromatography using n-butanol:ethanol:ammonium hydroxide (5:1:2;v/v) as solvent system. The results obtained showed that 90% of the radioactivity was protein bound and strongly suggest that this material is thyroglobulin.

β-1, 3-Glucan attenuated chronic unpredictable mild stress induced cognitive impairment in rodents via normalizing corticosterone levels

2020 ◽  
Vol 20 ◽  
Author(s):  
Saniya Hashim Khan ◽  
Sheraz Khan ◽  
Inamullah Khan ◽  
Narmeen Hashim
Keyword(s):  
Water Maze ◽  
Memory Impairment ◽  
Glucocorticoid Receptors ◽  
Therapeutic Potential ◽  
Mild Stress ◽  
Chronic Unpredictable Mild Stress ◽  
Neuroprotective Effects ◽  
Injurious Effect ◽  
Naturally Occurring ◽  
Dose Dependent

Background: Chronic stress elevates the cortisol beyond normal levels, which affects cognition including learning & memory. This injurious effect is primarily mediated via over excitation of metabotropic glucocorticoid receptors (mGR). Methods: The present study was aimed appraise the neuroprotective effects of naturally occurring molecule β-1,3-glucan by interfering with stress-cortisol-mGR axis. Our data of virtual screening (in silico) exhibited the promising interactions of βglucan with the mGR. Therefore, the study was extended to evaluate its efficacy (2.5, 5 and 10 mg/kg/ i.p) in an animal model of chronic unpredictable mild stress (CUMS, 28 days) induced memory impairment. Results: Results of the current study revealed the β-glucan provided dose dependent protection against deleterious effects of stress on learning and memory associated parameters observed in Morris water maze (MWM) task. At higher tested doses, it has also significantly antagonized the stress induced weight loss and corticosterone elevation. Conclusion: From these findings, it can be deduced that the β-glucan possesses therapeutic potential against stress induced memory impairment, and this effect can be attributed to its normalizing effect on corticosterone levels.

scholarly journals Cochleate formulations of amphotericin b designed for oral administration using a naturally occurring phospholipid

2021 ◽  
pp. 120688
Author(s):  
Antonio Lipa-Castro ◽  
Valérie Nicolas ◽  
Angelina Angelova ◽  
Ghozlene Mekhloufi ◽  
Bastien Prost ◽  
...  
Keyword(s):  
Oral Administration ◽  
Amphotericin B ◽  
Naturally Occurring

scholarly journals Effect of Photosensitization Mediated by Curcumin on Carotenoid and Aflatoxin Content in Different Maize Varieties

2021 ◽  
Vol 11 (13) ◽  
pp. 5902
Author(s):  
Rafael Nguenha ◽  
Maral Seidi Damyeh ◽  
Anh D. T. Phan ◽  
Hung T. Hong ◽  
Mridusmita Chaliha ◽  
...  
Keyword(s):  
Health Risks ◽  
Carotenoid Content ◽  
Naturally Occurring ◽  
Maize Varieties ◽  
Food And Feed ◽  
Maize Kernels ◽  
Dose Dependent ◽  
Preservation Technique ◽  
Scanning Electron

Mycotoxins are naturally occurring toxins produced by certain types of fungi that contaminate food and feed, posing serious health risks to human and livestock. This study evaluated the combination of blue light with curcumin to inactivate Aspergillus flavus spores, its effect on aflatoxin B1 (AFB1) production and maintaining carotenoid content in three maize varieties. The study was first conducted in vitro, and the spore suspensions (104 CFU·mL−1) were treated with four curcumin concentrations (25 and 50 µM in ethanol, 1000 and 1250 µM in propylene glycol) and illuminated at different light doses from 0 to 130.3 J·cm−2. The photoinactivation efficiency was light-dose dependent with the highest photoinactivation of 2.3 log CFU·mL−1 achieved using 1000 µM curcumin at 104.2 J·cm−2. Scanning electron microscopy revealed cell wall deformations as well as less density in photosensitized cells. Photosensitization of maize kernels gave rise to a complete reduction in the viability of A. flavus and therefore inhibition of AFB1 production, while no significant (p > 0.05) effect was observed using either light or curcumin. Moreover, photosensitization did not affect the carotenoids in all the studied maize varieties. The results suggest that photosensitization is a green alternative preservation technique to decontaminate maize kernels and reduce consumer exposure to AFB1 without any effect on carotenoid content.

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