Search results for "Absorption"
showing 10 items of 2701 documents
Comparison of segmental-dependent permeability in human and in situ perfusion model in rat.
2017
Abstract Nowadays, alternative methods have been developed to predict intestinal permeability values in human as in vitro, in situ or ex vivo methods. They were developed by the necessity to avoid the problems of the human permeability experiments. However, determination of human permeability is needed to properly validate the alternative methods. For this reason, recently, Dahlgren et al. published an indirect method based on a deconvolution technique to estimate the human permeability in different gastrointestinal segments (jejunum, ileum and colon). Therefore, the objective of this research was to demonstrate that Doluisio technique is a useful method to predict the human permeability in…
Influence of a Commercial Lead Apron on Patient Skin Dose Delivered During Oral and Maxillofacial Examinations under Cone Beam Computed Tomography (C…
2017
The purpose of this paper is to investigate the impact of a commercial lead apron on patient skin dose delivered during maxillofacial CBCT in five critical regions by means of solid-state-dosimetry. Five anatomical regions (thyroid gland, left and right breast, gonads, back of the phantom torso) in an adult female anthropomorphic phantom were selected for dose measurement by means of the highly sensitive solid-state dosimeter QUART didoSVM. Ten repeated single exposures were assessed for each patient body region for a total of five commercial CBCT devices with and without a lead apron present. Shielded and non-shielded exposures were compared under the paired Wilcoxon test, with absolute an…
Pharmacokinetics and bioavailability of diclofenac in the rat.
1991
Diclofenac sodium is a widely used drug with interesting absorption and disposition features when administered to laboratory animals. The present study was undertaken to assess the pharmacokinetics of the drug after iv and gastrointestinal dosing to rats. Renal excretion of unchanged drug was negligible, but biliary excretion of the drug (unchanged and conjugated) was detected in bile duct-cannulated rats; it accounted for 27.2 and 31.2% of the total dose following iv and intraduodenal administration, respectively. Most of the drug excreted in the bile was conjugated diclofenac; unchanged drug accounted for only 4.7 and 5.4% of total diclofenac excreted in the bile after iv and intraduodena…
The influence of active secretion processes on intestinal absorption of salbutamol in the rat.
2001
Abstract Salbutamol was perfused in the small intestine of rat using a standard rat gut ‘in situ’ preparation: (1) in inhibitor-free solution at seven different concentrations (0.15, 0.29, 1.20, 5.0, 9.0, 13.0 and 18.0 mM); (2) at a 0.29 mM concentration – thought to be close to the allometric dose in man – in the presence of a non-specific enzyme inhibitor, sodium azide (0.3, 3.0 and 6.0 mM); and (3) at 0.29 mM in the presence of a selective secretion inhibitor, verapamil (10.0 and 20.0 mM). In free solution, the mixed-order rate constants, k ′ a , of salbutamol increase as the solute concentration increases until an apparent asymptotic value is reached. This could be due to the saturation…
Carnitine transport into muscular cells. inhibition of transport and cell growth by mildronate
2000
Carnitine is involved in the transfer of fatty acids across mitochondrial membranes. Carnitine is found in dairy and meat products, but is also biosynthesized from lysine and methionine via a process that, in rat, takes place essentially in the liver. After intestinal absorption or hepatic biosynthesis, carnitine is transferred to organs whose metabolism is dependent on fatty acid oxidation, such as heart and skeletal muscle. In skeletal muscle, carnitine concentration was found to be 50 times higher than in the plasma, implicating an active transport system for carnitine. In this study, we characterized this transport in isolated rat myotubes, established mouse C2C12 myoblastic cells, and …
Steatocrit test after a standard fatty meal: A new simple and sensitive test to detect malabsorption
1991
The steatocrit test, a simple semiquantitative method for determining fat content in stool, was performed after a standard fatty meal to detect malabsorption in patients with celiac disease. Thirty-seven children (mean age 2.6 +/- 2.1 years) with total atrophy of the intestinal villi and 79 controls (mean age 3.5 +/- 2.8 years) were studied. All subjects underwent a small-bowel biopsy, a D-xylose absorption test, a rapid triglyceride absorption test, and a steatocrit determination first on an uncontrolled diet and then again after a standard fatty meal. The steatocrit test after a fatty meal did not detect any false-positive or false-negative results, while the D-xylose test showed two fals…
Coeliac disease: Oral ulcer prevalence, assessment of risk and association with gluten-free diet in children.
2008
Aims. Oral mucosal lesions may be markers of chronic gastrointestinal disorders, such as those causing malabsorption. Our objectives were to assess the prevalence of recurrent oral aphthous-like ulcers in coeliac disease patients living in the Mediterranean area, and to evaluate the impact of a gluten-free diet. Methods. A test group of 269 patients (age range 3-17 years) with coeliac disease confirmed both serologically and histologically was compared with a control group of 575 otherwise clinically healthy subjects for the presence, or a positive history of aphthous-like ulcers. Coeliac disease patients with aphthous-like ulcers were re-evaluated 1-year after starting a gluten-free diet. …
Bioavailability of nevirapine in rats after oral and subcutaneous administration, in vivo absorption from gastrointestinal segments and effect of bil…
2011
Abstract Nevirapine is a non-nucleoside reverse transcriptase inhibitor of human immunodeficiency virus type-1. The usual dosing regimen is 200 mg twice/day. Reducing the dosing frequency would significantly improve treatment adherence and quality of life of patients. To study new forms of administration, it is necessary to do pre-clinical studies and know the absorption characteristics of nevirapine in laboratory animals. However, there are no studies about its bioavailability in rats and hardly any about its pharmacokinetic. The objectives of this study were to describe the pharmacokinetics of nevirapine in rats after intravenous, oral and subcutaneous administration, to assess its absorp…
Pancreatic dysfunction and its association with fat malabsorption in HIV infected children
1998
Background—Nutrient malabsorption frequently occurs in HIV infected children, but very few studies have investigated exocrine pancreatic digestive capacity in these cases.Aims—To investigate pancreatic function in HIV infected children and to determine whether faecal fat loss, a prominent feature of intestinal dysfunction, is associated with pancreatic dysfunction.Patients—Forty seven children with HIV infection without apparent pancreatic disease and 45 sex and age matched healthy controls.Methods—Pancreatic function was evaluated by measuring elastase 1 concentration and chymotrypsin activity in stools by ELISA and colorimetric methods, respectively. Intestinal function was evaluated by m…
Immunologic and absorptive tests in celiac disease: can they replace intestinal biopsies?
1993
The sensitivity and specificity of several immunologic and absorption tests were determined in infants with celiac disease (31 male, 39 female; median age, 2.6 years) in different phases of the disease and in a group of control subjects with chronic diarrhea of different etiologies (32 male, 28 female; median age, 1.2 years). Intestinal biopsy was performed both in the patients and in the controls as a 'gold standard' for the diagnosis. The anti-gliadin antibody (AGA) IgG values showed a sensitivity of 89% and a specificity of 47%; AGA IgA were 69% sensitive and 92% specific; anti-endomysial antibodies (EmA) were 100% sensitive and 97% specific; the xylose test was 71% sensitive and 53% spe…