Effect of a single oral dose of pp?DDT on the absorption of nutrients in vitro and on brush border enzymes in rat intestine

1982 ◽  
Vol 49 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Pradeep K. Dudeja ◽  
Akhtar Mahmood
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Brush Border ◽  
Rat Intestine ◽  
Brush Border Enzymes

Control of Brush Border Enzymes by Dexamethasone in the Fetal Rat Intestine Cultured In Vitro

1982 ◽  
Vol 1 (2) ◽  
pp. 257-266 ◽  
Author(s):  
P. M. Simon-Assmann ◽  
M. Kedinger ◽  
J. F. Grenier ◽  
K. Haffen
Keyword(s):  
Brush Border ◽  
Rat Intestine ◽  
Brush Border Enzymes ◽  
Fetal Rat

Effect of Aspirin on the Thrombelastogram of Human Blood

1973 ◽  
Vol 30 (03) ◽  
pp. 494-498 ◽  
Author(s):  
G de Gaetano ◽  
J Vermylen
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Platelet Function ◽  
Human Blood ◽  
Platelet Rich Plasma ◽  
Plasma Samples ◽  
Release Reaction ◽  
Platelet Release

SummaryThrombelastograms of both native blood and re-calcified platelet-rich plasma samples taken from subjects given a single oral dose of aspirin (1 gram) were not significantly different from the pretreatment recordings. Aspirin also did not modify the thrombelastogram when preincubated in vitro with platelet-rich plasma at concentrations inhibiting the platelet “release reaction” by collagen. Thrombelastography therefore cannot evaluate the effect of aspirin on platelet function.

Cubilin and megalin expression and their interaction in the rat intestine: effect of thyroidectomy

2001 ◽  
Vol 281 (5) ◽  
pp. E900-E907 ◽  
Author(s):  
Raghunatha R. Yammani ◽  
Shakuntla Seetharam ◽  
Bellur Seetharam
Keyword(s):  
Brush Border ◽  
Intrinsic Factor ◽  
Immunoblot Analysis ◽  
Rat Intestine ◽  
Complement Components ◽  
Protein Levels ◽  
Intestinal Brush Border ◽  
Molecular Masses ◽  
Epidermal Growth

Cubilin is a 460-kDa multipurpose, multidomain receptor that contains an NH2-terminal 110-residue segment followed by 8 epidermal growth factor (EGF)-like repeats and a contiguous stretch (representing nearly 88% of its mass) of 27 CUB (initially found in complement components C1r/C1s, Uegf, and bone morphogenic protein-1) domains. Cubilin binds to intrinsic factor (IF)-cobalamin (cbl, vitamin B12) complex and promotes the ileal transport of cbl. The 460-kDa form of cubilin is the predominant form present in the apical brush-border membranes of rat intestine, kidney, and yolk sac, but a 230-kDa form of cubilin is also noted in the intestinal membranes. In thyroidectomized (TDX) rats, levels of intestinal brush-border IF-[57Co]-labeled cbl binding, 460-kDa cubilin protein levels and tissue (kidney) accumulation of cbl were reduced by ∼70%. Immunoblot analysis using cubilin antiserum of intestinal total membranes from TDX rats revealed cubilin fragments with molecular masses of 200 and 300 kDa. Both of these bands, along with the 230-kDa band detected in the total membranes of control rats and unlike the 460-kDa form, failed to react with antiserum to EGF. Mucosal membrane cubilin associated with megalin was reduced from ∼12% in control to ∼4% in TDX rats, and this decreased association was not due to altered megalin levels. Thyroxine treatment of TDX rats resulted in reversal of all of these effects, including an increase to nearly 24% of cubilin associated with megalin. In vitro, megalin binding to cubilin occurred with the NH2-terminal region that contained the EGF-like repeats and CUB domains 1 and 2 but not with a downstream region that contained CUB domains 2–10. These studies indicate that thyroxine deficiency in rats results in decreased uptake and tissue accumulation of cbl caused mainly by destabilization and deficit of cubilin in the intestinal brush border.

Effects of Ginkgo biloba Extract Ingestion on the Pharmacokinetics of Talinolol in Healthy Chinese Volunteers

2009 ◽  
Vol 43 (5) ◽  
pp. 944-949 ◽  
Author(s):  
Lan Fan ◽  
Gong-You Tao ◽  
Guo Wang ◽  
Yao Chen ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Ginkgo Biloba ◽  
High Performance ◽  
Plasma Concentrations ◽  
Ginkgo Biloba Extract ◽  
Maximum Plasma ◽  
Time Curve ◽  
P Glycoprotein

Background Ginkgo biloba extract (GBE), the best selling herbal medicine in the world, has been reported to inhibit P-glycoprotein in vitro. However, the effects of GBE on P-glycoprotein activity in humans have not been clarified. Objective To investigate the effects of single and repeated GBE ingestion on the oral pharmacokinetics of talinolol, a substrate drug for P-glycoprotein in humans. Methods Ten unrelated healthy male volunteers were selected to participate in a 3-stage sequential study. Plasma concentrations of talinolol from 0 to 24 hours were measured by high-performance liquid chromatography after talinolol 100 mg was administrated alone, with a single oral dose of GBE (120 mg), and after 14 days of repeated GBE ingestion (360 mg/day). Results A single oral dose of GBE did not affect the pharmacokinetics of talinolol. Repeated ingestion of GBE increased the talinolol maximum plasma concentration (Cmax) by 36% (90% CI 10 to 68; p = 0.025), the area under the concentration-time curve (AUC)0-24 by 26% (90% CI 11 to 43; p = 0.008) and AUC0-∞ by 22% (90% CI 8 to 37; p = 0.014), respectively, without significant changes in elimination half-life and the time to Cmax. Conclusions Our results suggest that long-term use of GBE significantly influenced talinolol disposition in humans, likely by affecting the activity of P-glycoprotein and/or other drug transporters.

scholarly journals The enterocyte microvillus is a vesicle-generating organelle

2009 ◽  
Vol 185 (7) ◽  
pp. 1285-1298 ◽  
Author(s):  
Russell E. McConnell ◽  
James N. Higginbotham ◽  
David A. Shifrin ◽  
David L. Tabb ◽  
Robert J. Coffey ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Surface ◽  
Intestinal Lumen ◽  
Intestinal Alkaline Phosphatase ◽  
Brush Border Enzymes ◽  
Membrane Surface Area ◽  
Catalytically Active ◽  
The Right

For decades, enterocyte brush border microvilli have been viewed as passive cytoskeletal scaffolds that serve to increase apical membrane surface area. However, recent studies revealed that in the in vitro context of isolated brush borders, myosin-1a (myo1a) powers the sliding of microvillar membrane along core actin bundles. This activity also leads to the shedding of small vesicles from microvillar tips, suggesting that microvilli may function as vesicle-generating organelles in vivo. In this study, we present data in support of this hypothesis, showing that enterocyte microvilli release unilamellar vesicles into the intestinal lumen; these vesicles retain the right side out orientation of microvillar membrane, contain catalytically active brush border enzymes, and are specifically enriched in intestinal alkaline phosphatase. Moreover, myo1a knockout mice demonstrate striking perturbations in vesicle production, clearly implicating this motor in the in vivo regulation of this novel activity. In combination, these data show that microvilli function as vesicle-generating organelles, which enable enterocytes to deploy catalytic activities into the intestinal lumen.

scholarly journals Probenecid inhibits SARS-CoV-2 replication in vivo and in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jackelyn Murray ◽  
Robert J. Hogan ◽  
David E. Martin ◽  
Kathy Blahunka ◽  
Fred D. Sancilio ◽  
...  
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Virus Replication ◽  
Mammalian Cells ◽  
Clinical Utility ◽  
Plasma Concentrations ◽  
Hamster Model ◽  
Potential Clinical Utility

AbstractEffective vaccines are slowing the COVID-19 pandemic, but SARS-CoV-2 will likely remain an issue in the future making it important to have therapeutics to treat patients. There are few options for treating patients with COVID-19. We show probenecid potently blocks SARS-CoV-2 replication in mammalian cells and virus replication in a hamster model. Furthermore, we demonstrate that plasma concentrations up to 50-fold higher than the protein binding adjusted IC90 value are achievable for 24 h following a single oral dose. These data support the potential clinical utility of probenecid to control SARS-CoV-2 infection in humans.

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