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PubMedDate not supplied

Transperitoneal absorption of intralipid in rats: total serum fatty acids and triglyceride after absorption.

Intralipid 20% was injected percutaneously into the peritoneum of 58 female rats. The rats were divided into seven groups (with an additional control group of 35 rats). To measure transperitoneal absorption, we determined the serum fatty acid and triglyceride concentrations at 3-hr intervals for 24 hr, and found a considerable increase in all of the levels measured, with a maximum at about 6 hr. The serum triglyceride levels never rose above a mean value of 200 mg/100 ml. A second and smaller rise was seen after 15 hr, declining again to the initial values. The relative proportions of the different fatty acids changed, but not drastically.

Absorption↗
PubMed1991

Absorption and disposition of epithiosteroids in rats (2): Avoidance of first-pass metabolism of mepitiostane by lymphatic absorption.

1. Absorption of mepitiostane (MP) from the gastrointestinal tract was examined using thoracic duct-cannulated rats. 2. When 14C-MP was administered into the small intestine, 34% of the radioactivity was recovered in the 6-h thoracic duct lymph. More than 90% of this radioactivity was due to unchanged MP and most of the MP in the lymph was carried in the lipid core of the chylomicrons and VLDL. 3. Radioactivity in the portal blood was extensively extracted by the liver and excreted into bile as polar metabolites. Thus, most unchanged MP which entered the systemic circulation following oral administration was drug absorbed via the intestinal lymphatics. 4. MP avoids the first-pass effect by lymphatic adsorption.

Androstanols↗
PubMed1976

Thiamine absorption in the rat. IV. Effects of caffeic acid (3,4-dihydroxycinnamic acid) upon absorption and active transport of thiamine.

The effects upon thiamine absorption in-vitro and in-vivo by caffeic acid (a thiamine antagonist isolated from bracken) was studied, partly using 14C-thiamine. It was again shown that caffeic acid reduced the quantity of thiochrome positive thiamine, dependant upon the concentration ratio caffeic acid/thiamine. Caffeic acid was able to pass across the intestinal wall and to exert its antithiamine effect in the serosal incubation fluid. When caffeic acid was present in the mucosal fluid the amount of thiochrome positive thiamine passed to the serosal side was diminished according to the mucosal caffeic acid concentration. In-vitro studies with 14C-thiamine revealed, however, that thiamine modified and turned into a thiochrome negative form by caffeic acid was absorbed similarly to unaffected thiamine. Active transport in-vitro of thiamine was significantly inhibited by the presence of caffeic acid.

Animals↗
PubMedDate not supplied

[Mechanisms of calcium absorption and absorption modifiers based in the elaboration of a low-cost diet for osteoporosis patients].

This article contemplates recent investigations about calcium absorption and offers inexpensive alternatives to enhance dietary calcium bioavailability, also focused in bone mass loss, which may lead to osteoporosis. Recent data about risk factors, calcium metabolism, economical data, and nutrition tables were collected, to get a general overview of the problem, and expose it to health care and food manufacture professionals. We conclude: a) osteoporosis has an expensive socioeconomical cost, b) most of the actual therapies are expensive and have a limited therapeutical benefit, c) the typical mexican diet is calcium rich, but has poor bioavailability, d) it is easier to prevent bone mass loss than recover it, e) a rich calcium diet with a good bioavailability through life, specially in childhood, will attain a peak bone mass, f) improvement of calcium bioavailability is technically possible by food processing. G) by following a few principles calcium bioavailability can be improved in a normal diet at a low cost. Considering all of this, in theory, it could be possible to reduce the morbidity-mortality rate caused by osteoporosis in mexican people.

Bone Density↗
PubMed1975

Carbohydrate absorption. Studies on the glucose transport by isolated brush border membranes. A contribution towards an understanding of the molecular mechanism of sugar absorption.

From investigations, mainly on intact in vitro preparations of small intestine, it has been established that the epithelial cell carries out digestion as well as absorption of carbohydrates, i.e. the luminal (brush border) plasma membrane contains di- and poly-saccharidases for the degradation of carbohydrates to monosaccharides as well as transport systems for monosaccharides. Recently, an intact glucose transport system has been demonstrated in isolated membranes from rat intestinal brush borders. In the isolated membranes, glucose transport has the characteristics expected for 'facilitated diffusion' of glucose coupled to Na+ translocation. The Na+-dependent uptake of glucose can be influenced by electrical potentials across the brush border membrane, which indicates that the positive charge of Na+, associated with sugar uptake, is not compensated by the counter-movement of another cation, e.g. K+, or by the co-movement of an anion via the same glucose 'carrier'. In other words, the Na+-coupled D-glucose transport is linked to a charge translocation - it is electrogenic. The apparent Na+ independence of glucose transport in vivo and the accumulation of glucose against a glucose as well as a Na+ concentration gradient by isolated epithelial cells may be explained by the 'ion gradient' model of Crane and Schultz and Zalusky provided the electrical membrane potential is high under these conditions and the electrochemical potential of Na+ serves as driving force for 'active' glucose transport.

Animals↗
PubMed1975

Thiamine absorption in the rat. III. Effect of ethyl alcohol on active absorption of thiamine in-vitro.

The effect of ethanol on active thiamine absorption in-vitro was studied in everted sacs of rat small intestines. Non-adapted, normally fed rats were used which had not previously been treated with alcohol. It was found that ethanol at 1% final concentration significantly increased active transport of thiamine to approximately fourfold. It is suggested that increased permeability of the intestinal wall plays a major role in phenomenon.

Animals↗
PubMed1991

An in vitro evaluation of metabolism and poor membrane permeation impeding intestinal absorption of leucine enkephalin, and methods to increase absorption.

The goals of this study were to evaluate how metabolism and poor membrane permeability act as barriers to absorption of a model peptide, leucine enkephalin (YGGFL), and how those barriers can be overcome. The in vitro everted rat intestine method was used. YGGFL was rapidly metabolized when exposed to the mucosa of the jejunum, and destyrosyl leucine enkephalin was formed. Metabolism was slower for ileal intestinal segments, however, and was almost absent when colonic segments were used. The aminopeptidase inhibitor boroleucine, an aminoboronic acid derivative, reduced the YGGFL metabolism rate 2-fold at 1/100th the concentration of substrate when the intestine was simultaneously exposed to substrate and inhibitor. Pretreatment of the intestine with boroleucine further reduced the metabolism rate. Thiorphan, an inhibitor of endopeptidase 24.11, had additive inhibitory effects with boroleucine. Inhibition of metabolism alone did not enable YGGFL to permeate the membrane. The permeability enhancer, sodium glycocholate, also did not alone enable membrane permeation. Substantial YGGFL permeated the membrane only when metabolism was inhibited and permeability was enhanced. EDTA had both these effects.

Animals↗
PubMed1977

In vitro studies of intestinal endotoxin absorption. I. Kinetics of absorption in the isolated everted gut sac.

Previous studies have shown in a qualitative manner that endotoxin can cross gut epithelium, but precise quantitation has not been possible. The present studies were undertaken to measure quantitatively the mucosal to serosal unidirectional flux of endotoxin with the use of an in vitro rat gut sac preparation. 51Cr-Labeled endotoxin was placed in the mucosal bath in concentrations ranging from 0.05 to 2.0 mg per ml. Over a 2-hr period of time, a small amount of endotoxin was transported transmurally, which was shown chromatographically to be similar to the starting material and which retained its toxic and immunogenic properties. It was first shown that the presence of 2.0 mg per ml of endotoxin in the mucosal bath did not significantly alter the tissue's histology or permeability to 3-O-methyl-D-glucose. When unidirectional fluxes were measured, it was found that the flux was not proportional to the endotoxin concentration as would be expected with a passively permeable solute, but rather its transport system became "saturated," displaying a maximum transport rate of 4.72 (mug per cm) per 2 hr and a Km of 0.425 mg per ml. The isolated gut sac provides an excellent model for the precise study of factors involved in endotoxin absorption.

Animals↗
PubMed1986

Digestion of bentiromide and absorption of xylose in healthy cats and absorption of xylose in cats with infiltrative intestinal disease.

The digestion of bentiromide and the absorption of D-xylose was measured in 17 clinically healthy cats. The plasma xylose concentrations of the healthy cats were compared with values from 9 cats with diffuse infiltrative intestinal disease. The cats were administered 16.7 mg of bentiromide/kg and 0.5 g of xylose/kg via a stomach tube. Plasma samples were obtained before administration and 30, 60, 90, and 120 minutes after administration. The maximum mean plasma p-aminobenzoic acid concentration occurred at 60 minutes, with a value of 386 +/- 134 micrograms/dl (mean +/- SD). The maximum mean plasma xylose concentration also occurred at 60 minutes, with a value of 26.0 +/- 9.2 mg/dl. Plasma concentrations of p-aminobenzoic acid and xylose were lower in healthy cats than those reported for healthy dogs. There was no significant difference between xylose concentrations in healthy cats and cats with infiltrative intestinal disease.

4-Aminobenzoic Acid↗
PubMed1985

[Absorption, distribution, metabolism and excretion of bacmecillinam. I. Absorption, distribution, metabolism and excretion of 14C-bacmecillinam following oral administration to rats].

The pharmacokinetics of bacmecillinam (KW-1100), a new semisynthetic penicillin, was studied. Plasma levels, tissue distribution, metabolites and urinary and biliary excretion of mecillinam after oral administration of KW-1100 were studied in rats given a dose of 20 mg/kg (as mecillinam). The absorption of 14C-KW-1100 was so rapid that the level in blood was found to reach the peak 30 minutes after administration. 14C-KW-1100 was distributed widely into various tissues and relatively high distribution was noted in liver, kidney, adrenal gland and spleen. No accumulation of 14C-KW-1100 in any tissue was found. It was excreted rapidly from each tissue. Within 24 hours after administration of KW-1100, approximately 86% of the given dose was excreted. And within 72 hours, approximately 97% of the dose was excreted. Excretions in urine and feces within 72 hours after KW-1100 administration were 39.5 and 57.4% of the given dose, respectively. Biliary excretion was 2.0% of the given dose within 24 hours after administration of KW-1100. The major metabolite in the plasma at peak time (30 minutes) was mecillinam (50.5%). The major metabolite in the urine (0 approximately 8 hours) was mecillinam (52.2%), too. The minor metabolites were 5,5-dimethyl-2-(1'-formamidomethyl)-thiazolidine-1',4-dicarboxylat e(M-1), 6-beta-[(hexahydro-1H-azepin-1-yl)-methyleneamino]-penicilloic acid (M-6) and M-4.

Administration, Oral↗
PubMed1980

[Studies on the absorption, excretion and distribution of aclacinomycin A: absorption, excretion and distribution of aclacinomycin A in mice, rabbits and dogs by photometric assay (author's transl)].

An anthracycline antitumor antibiotic, aclacinomycin A, was given to mice, rabbits or dogs intravenously to study the pharmacokinetics by photometric assay based on the absorption of anthracycline ring. The drug was rapidly eliminated from the blood in these animals. Drug levels were much higher in the blood cells than in the plasma. Tissue levels in dogs were 50 approximately 100 times higher than the blood levels, which showed the drug was rapidly transferred from the blood to tissues after administration. Higher levels were observed in the lungs, spleen and lymph nodes, where the drug was present as aclacinomycin A itself and the glycoside-type metabolites that were biologically active. The active form was also detected in the pancreas, heart, thymus, bone marrow and gastrointestinal tract. In the liver and kidneys, biologically inactive aglycone-type metabolites were observed. About 2 approximately 4% of the drug given to rabbits or dogs was recovered in the urine by 72 hours after administration, in which only 10% of the excreted drug was active form in rabbits but about 65% in dogs. The rest was inactive aglycone-type metabolites that were excreted almost in the conjugated form. Biliary excretion also contributed to the total clearance of the drug. Aclacinomycin A was absorbed even by oral administration in rabbits and dogs. Tissue distribution of the drug orally given to dogs was similar to that in intravenous administration, except that higher levels of active form were detected in the gastrointestinal tract and of inactive form in the liver.

Absorption↗
PubMed1987

5 K extended X-ray absorption fine structure and 40 K 10-s resolved extended X-ray absorption fine structure studies of photolyzed carboxymyoglobin.

A previous extended X-ray absorption fine structure (EXAFS) study of photolyzed carboxymyoglobin (MbCO) [Chance, B., Fischetti, R., & Powers, L. (1983) Biochemistry 22, 3820-3829; Powers, L., Sessler, J. L., Woolery, G. L., & Chance, B. (1984) Biochemistry 23, 5519-5523] has provoked much discussion on the heme structure of the photoproduct (MbCO). The EXAFS interpretation that the Fe-CO distance increases by no more than 0.05 A following photodissociation has been regarded as inconsistent with optical, infrared, and magnetic susceptibility studies [Fiamingo, F. G., & Alben, J. O. (1985) Biochemistry 24, 7964-7970; Sassaroli, M., & Rousseau, D. L. (1986) J. Biol. Chem. 261, 16292-16294]. The present experiment was performed with well-characterized dry film samples in which MbCO molecules were embedded in a poly(vinyl alcohol) matrix [Teng, T. Y., & Huang, H. W. (1986) Biochim. Biophys. Acta 874, 13-18]. The sample had a high protein concentration (12 mM) to yield adequate EXAFS signals but was very thin (40 micron) so that complete photolysis could be easily achieved by a single flash from a xenon lamp. Although the electronic state of MbCO resembles that of deoxymyoglobin (deoxy-Mb), direct comparison of EXAFS spectra indicates that structurally MbCO is much closer to MbCO than to deoxy-Mb.(ABSTRACT TRUNCATED AT 250 WORDS)

Heme↗
PubMed1977

Absorption, plasma transport, and cellular retention of cobalamin analogues in the rabbit. Evidence for the existence of multiple mechanisms that prevent the absorption and tissue dissemination of naturally occurring cobalamin analogues.

Analogues of cobalamin (Cbl; vitamin B(12)) are prevalent in nature as a result of bacterial synthesis, and are of additional interest because of their potential use as antimetabolites and chemotherapeutic agents. We have synthesized 14 Cbl analogues containing (57)Co and have compared their gastrointestinal absorption, plasma transport, and cellular retention to that of [(58)Co]Cbl in rabbits. Many of the Cbl analogues were bound with low affinity by intrinsic factor, and none of these [(57)Co]Cbl analogues were taken up by the ileum or absorbed into the body in amounts comparable to that of [(58)Co]Cbl. The Cbl analogues that were bound by intrinsic factor with high affinity were taken up by the ileum but, in many cases, they were retained there in significant amounts. Most of the Cbl analogues were bound by plasma transcobalamin II with high affinity and all of these transcobalamin II-[(57)Co]Cbl analogue complexes were taken up by a variety of tissues in a manner that was indistinguishable from that of transcobalamin II-[(58)Co]Cbl. The few analogues that were bound by transcobalamin II with low affinity were taken up by tissues in lesser amounts, and 20-70% of these analogues was rapidly excreted in the urine as occurs with native Cbl when it is present in plasma in unbound form. All of the Cbl analogues were bound by the granulocyte R-type Cbl-binding protein with high affinity and all of the R-type protein-[(57)Co]Cbl analogue complexes were cleared rapidly from plasma exclusively by hepatocytes as occurs with R-type protein-[(58)Co]Cbl. Some Cbl analogues were released back into the plasma and were disseminated among a variety of tissues via transcobalamin II as occurs with native Cbl. Other Cbl analogues were retained in the liver and eventually excreted in the feces and urine without accumulating in other tissues. These studies indicate that intrinsic factor and the ileum prevent certain Cbl analogues from entering the body and that the granulocyte R-type protein and hepatocytes prevent the dissemination of certain Cbl analogues that may gain entry such as during infections with Cbl analogue-producing bacteria. The fact that transcobalamin II binds and transports a large number of Cbl analogues indicates that these protective mechanisms can be circumvented and supports the feasibility of using Cbl analogues as antimetabolites in vivo.

Animals↗
PubMed1997

[Determination of trace silver in surface water samples by flame atomic absorption with continuous flow on-line absorption preconcentration].

In a continuous flow on-line preconcentration system, trace silver was adsorbed onto activated carbon particles packed in micro colum at pH 1, eluted with 0.3 ml of 10 g/L Na2S2O3 solution and determined by flame atomic absorption spectrometry. For surface water samples, 25 ml sufficed precise determination of silver at level of microgram/L. The relative standard deviation of 10 parallel sample determinations was 6.9%. The proposed method was successfully applied to water samples with recoveries ranging from 93.2% to 104.6% and a throughout of 7-8 sampling/h.

Silver↗
PubMed1978

Atomic absorption spectrophotometry of chromium in serum and urine with a modified Perkin-Elmer 603 atomic absorption spectrophotometer.

Modification of a Perkin-Elmer 603 atomic absorption spectrophotometer by adding a high-intensity tungsten-halogen lamp for background correction significantly improved the detection limit for elements that have analytical wavelengths in the near-ultraviolet and visible regions. Chromium in human serum and urine can be measured, with a simplified sample-handling technique, in concentrations of less than 0.1 microgram/liter. For comparison, the mean value for chromium in the serum of eight men was 0.14 microgram/liter.

Chromium↗