Search results for "Intestine"

Active contractility of the lymphangion and coordination of lymphangion chains

1976

In Situ Study of the Effect of Naringin, Talinolol and Protein-Energy Undernutrition on Intestinal Absorption of Saquinavir in Rats

2011

To study the potential interactions of naringin (NAR), talinolol (TAL) and protein-energy undernutrition (PEU) in the absorption process of saquinavir (SQV), perfusion experiments were performed in the small intestine of rats at different SQV concentrations. The results obtained demonstrated that SQV intestinal absorption was described by simultaneous passive diffusion (kdif = 3.44 hr) and saturable absorption (Vma = 127.31 lM ⁄ hr; Kma =1 0.50lM) together with a capacity-limited efflux (Vms = 270.53 lM ⁄ hr; Kms =2 3.44lM). The competitive inhibition constants of NAR on the SQV input and efflux processes were (IC50)a =3 .98l Ma nd(IC50)s = 5.00 lM, respectively. NAR significantly decreased…

Nonlinear intestinal absorption kinetics of cefuroxime axetil in rats.

1997

Cefuroxime is commercially available for parenteral administration as a sodium salt and for oral administration as cefuroxime axetil, the 1-(acetoxy)ethyl ester of the drug. Cefuroxime axetil is a prodrug of cefuroxime and has little, if any, antibacterial activity until hydrolyzed in vivo to cefuroxime. In this study, the absorption of cefuroxime axetil in the small intestines of anesthetized rats was investigated in situ, by perfusion at four concentrations (11.8, 5, 118 and 200 microM). Oral absorption of cefuroxime axetil can apparently be described as a specialized transport mechanism which obeys Michaelis-Menten kinetics. Parameters characterizing absorption of prodrug in free solutio…

Synthese, Verteilung und Ausscheidung von 14C markiertem 2-Phenyl-3-methyl-tetrahydro-1,4-oxazin (Preludin)

1958

A radioactive preludin preparation, C14 labelled on the 2-carbon of the tetrahydrooxazine ring, was injected into mice in doses of 100 mg/kg s.c. and rats in doses of 10 mg/kg i.v. The radioactivity of the tissues and excreta was followed for 48 hours. An activity concentration surpassing the average body concentration was obtained for a short time in the lungs and for a longer time in kidneys, liver and in the wall of stomach and small intestine. 95–99% of the total activity is found in the urine. The kidney excretion is virtually finished at the end of 8 hours; 1–5% appear after the 8th hour in faeces. No radioactivity was obtained from the expired CO2. The main excretion organs are kidne…

A new gene superfamily of pathogen-response (repat) genes in Lepidoptera: Classification and expression analysis

2012

Repat (REsponse to PAThogens) genes were first identified in the midgut of Spodoptera exigua (Lepidoptera: Noctuidae) in response to Bacillus thuringiensis and baculovirus exposure. Since then, additional repat gene homologs have been identified in different studies. In this study the comprehensive larval transcriptome from S. exigua was analyzed for the presence of novel repat-homolog sequences. These analyses revealed the presence of at least 46 repat genes in S. exigua, establishing a new gene superfamily in this species. Phylogenetic analysis and studies of conserved motifs in these hypothetical proteins have allowed their classification in two main classes, αREPAT and βREPAT. Studies o…

Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly’s midgut environment

2021

Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse’s ability to transmit trypanosomes by strengthening the fly’s natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse’s PM in order to establish an infection in the fly, and PM struc…

Colorectal Cancer Stem Cells: From the Crypt to the Clinic

2014

Since their first discovery, investigations of colorectal cancer stem cells (CSCs) have revealed some unexpected properties, including a high degree of heterogeneity and plasticity. By exploiting a combination of genetic, epigenetic, and microenvironmental factors, colorectal CSCs metastasize, resist chemotherapy, and continually adapt to a changing microenvironment, representing a formidable challenge to cancer eradication. Here, we review the current understanding of colorectal CSCs, including their origin, relationship to stem cells of the intestine, phenotypic characterization, and underlying regulatory mechanisms. We also discuss limitations to current preclinical models of colorectal …

Technical characteristics can make the difference in a surgical linear stapler. Or not?

2015

Background Anastomotic leak (AL) after gastrointestinal surgery is a severe complication associated with relevant short- and long-term sequelae. Most of the anastomosis are currently performed with a surgical stapler that is required to have appropriate characteristics to guarantee good performances. The aim of our study was to evaluate, in the laboratory, pressure resistance and tensile strength of anastomosis performed with different surgical linear staplers, available in the market. Materials and methods We have been studying three linear staplers, with diverse cartridges and staple heights, of three different companies, used for gastrointestinal anastomosis and gastric or intestinal clo…

In vitro models for the prediction of in vivo performance of oral dosage forms: Recent progress from partnership through the IMI OrBiTo collaboration

2019

The availability of in vitro tools that are constructed on the basis of a detailed knowledge of key aspects of gastrointestinal (GI) physiology and their impact on formulation performance and subsequent drug release behaviour is fundamental to the success and efficiency of oral drug product development. Over the last six years, the development and optimization of improved, biorelevant in vitro tools has been a cornerstone of the IMI OrBiTo (Oral Biopharmaceutics Tools) project. By bringing together key industry and academic partners, and by linking tool development and optimization to human studies to understand behaviour at the formulation/GI tract interface, the collaboration has enabled …

Lovastatin attenuates ionizing radiation-induced normal tissue damage in vivo.

2009

Abstract Background and purpose HMG-CoA-reductase inhibitors (statins) are widely used lipid-lowering drugs. Moreover, they have pleiotropic effects on cellular stress responses, proliferation and apoptosis in vitro . Here, we investigated whether lovastatin attenuates acute and subchronic ionizing radiation-induced normal tissue toxicity in vivo . Materials and methods Four hours to 24h after total body irradiation (6Gy) of Balb/c mice, acute pro-inflammatory and pro-fibrotic responses were analyzed. To comprise subchronic radiation toxicity, mice were irradiated twice with 2.5Gy and analyses were performed 3weeks after the first radiation treatment. Molecular markers of inflammation and f…