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PubMed1994

Effects of weaning and enterotoxigenic Escherichia coli on net absorption in the small intestine of pigs.

The purpose of this study was to measure the net absorption of fluid, sodium, potassium and chloride in the small intestine of weaned pigs and of their unweaned littermates and to correlate these values with villus height and crypt depth. Five pairs of segments of the small intestine were prepared in each of 80 pigs; the cranial segment of each pair was injected with an enterotoxigenic strain of Escherichia coli and the caudal segment with a control solution. Net absorption was measured on the day of weaning and four, seven, 11 and 14 days after weaning. In unweaned pigs the net absorption of fluid, potassium and chloride did not vary with time. In weaned pigs the net absorption of fluid in the control segments was significantly less on days 4, 7 and 14 after weaning and of sodium and chloride on days 4 and 7 than in unweaned littermates. In infected segments of weaned pigs the net absorption of fluid was significantly less than in unweaned littermates on day 11 and 14, of sodium and potassium on day 11 and of chloride on days 4 and 11 after weaning. Net absorption was negatively correlated with villus height but only in the infected segments of weaned pigs; no other correlations were found. It was concluded that after weaning the net absorption of fluid and electrolytes in the small intestine of pigs is temporarily decreased, a condition that may initiate diarrhoea.

Chlorides↗
PubMed1990

Solute-coupled liquid absorption from the pleural space.

The occurrence of a solute-coupled absorption of liquid from the pleural space was studied by measuring in anesthetized rabbits the volume of liquid of the right pleural space 1 h after injecting into it 2 ml of Ringer solution or of Ringer with an inhibitor of a Na(+)-Cl- coupled transport or of the Na+/K+ pump. Volume collected after Ringer was 1.56 +/- 0.08 ml. Initial volume being 2.2 ml, net absorption rate was 0.64 ml/h. Volume collected after disulfonic stilbene (0.1 mM) or bumetanide (0.1 mM) was 2.01 +/- 0.06 and 2.01 +/- 0.05 ml, respectively; net absorption rate was reduced to 0.19 ml/h. This suggests the occurrence of Na(+)-Cl- coupled transports. Volume collected after ouabain (0.5 mM) was 2.08 +/- 0.08 ml; net absorption rate was reduced to 0.12 ml/h. This suggests the occurrence of the Na+/K+ pump. The marked reduction in the hydrothorax absorption produced by the inhibitors shows the occurrence of a solute-coupled liquid absorption from the pleural space. Liquid absorbed through the visceral pleura by the solute-coupled transport should be removed by the Starling forces of pulmonary capillaries. Solute-coupled absorption of liquid through the parietal pleura should oppose the filtration caused by the Starling forces.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1983

Malathion percutaneous absorption after repeated administration to man.

Prediction of exposure and toxic potential of pesticides such as malathion are routinely based upon acute exposure and single-dose percutaneous absorption determination. What has become obvious with pesticide exposure such as the malathion spraying for the medfly is that chronic daily exposure is the more relevant situation. Our objective was to determine the percutaneous absorption of chronically applied malathion in man and to compare chronic absorption to single-dose absorption. The experimental design was to first topically apply [14C]malathion to human male volunteers. This procedure was followed by repeated administration of nonradioactive malathion to the same site of application (ventral forearm). [14C]Malathion was reapplied (Day 8) when urinary excretion of radioactivity from the first application reached minimum detectable levels. The first [14C]malathion absorption was compared to the second [14C]malathion application. The percutaneous absorption from the first [14C]malathion application was 4.48 +/- 1.3% (SD) of the applied dose. The absorption from the second [14C]malathion administration was 3.53 +/- 1.0%, a value not significantly (p greater than 0.05) different from the first application. Therefore, for malathion the single-dose application data are relevant for predicting the toxic potential for longer-term exposure.

Administration, Topical↗
PubMed1986

Influence of iron on plutonium absorption by the adult and neonatal rat.

To determine how iron affects plutonium absorption, adult rats were gavaged with 238Pu nitrate (pH 2) after they had been fed an iron-deficient diet or treated with iron supplements. Neonatal rats born to dams on an iron-deficient diet were also gavaged with 238Pu. An iron-deficient diet resulted in enhanced 238Pu absorption both in the adults and in neonates born to iron-deficient dams. Ferric iron increased 238Pu absorption 12-fold in adult rats; injected iron-dextran reduced that increase; gavaged ferrous iron reduced 238Pu absorption to one-third of the control value. Rat neonates absorbed 30 to 40 times as much 238Pu as adults; absorption was lowered in groups that received iron supplements: Iron-dextran caused a 50% reduction; ferric iron, 95%; and ferrous iron, greater than 95%. The results demonstrate an effect of the oxidation state of iron on plutonium absorption in adult rats different from that observed in suckling rats. The results suggest that the high rate of 238Pu absorption by neonatal animals is due not only to the permeability of their intestines but also to their high demand for iron.

Animals↗
PubMed1979

Critical appraisal of oral calcium load test for indirect assessment of intestinal calcium absorption.

Two methods of oral calcium load or tolerance test for the indirect assessment of calcium absorption were compared. In 16 patients in whom the diagnosis of absorptive hypercalciuria was made independently, an exaggerated urinary total calcium excretion during four hours following calcium load, indicative of increased calcium absorption according to the method of Pak et al., was found in 15 patients. An abnormally high increment in urinary calcium during third and fourth hours post-calcium load, suggestive of enhanced calcium absorption by the criteria of Broadus et al., was encountered in 14 patients. However, an exaggerated urinary total calcium following calcium load was found in all 7 patients with renal hypercalciuria, whereas only 4 were shown to have an enhanced increment in calcium excretion. It is concluded that both methods are equally reliable in the detection of increased calcium absorption in absorptive hypercalciuria. However, the technique of Broadus et al. is probably superior to that of Pak et al. in the disclosure of increased calcium absorption in renal hypercalciuria.

Administration, Oral↗
PubMed1983

The influence of tin, nickel, and cadmium on the intestinal absorption of iron.

The influence of increasing doses of cadmium, nickel, and tin on the net absorption of fluid as well as upon the absorption of 59Fe, administered as 59Fe-(FeSO4), from tied-off jejunal segments of male Sprague-Dawley rats were investigated. The three metals examined decreased the net absorption of fluid from the jejunal segments progressively with increasing metal doses. Cadmium was the most potent inhibitor of fluid absorption followed by tin and nickel. Tin, cadmium, and nickel diminished the absorption of 59Fe with increasing doses. The content of 59Fe of the jejunal tissue was not statistically significantly influenced by nickel, whereas tin as well as cadmium diminished the content of 59Fe significantly. Cadmium decreased the content of 59Fe to a greater extent than tin. Obviously nickel influences the rate-limiting process of iron absorption, i.e., the transfer of iron from mucosal cells into blood. Tin and cadmium appear to interact with the process of iron uptake on the surface within the mucosal cells as well as with the iron-releasing process at the contraluminal side. Cadmium as compared with tin is a stronger inhibitor for the processes involved in iron absorption.

Animals↗
PubMed1992

The absorption of hydrophobic chemicals across perfused rainbow trout gills: methodological aspects.

The absorption rates of 4-bromophenol, 2,4-dibromophenol, 3,4,5-trichloroguaiacol, and tetrachloroveratrol across fish gill epithelium have been measured in a perfused gill preparation from rainbow trout (Oncorhynchus mykiss). In additional experiments the absorption rate of tetrachloroveratrol was measured in free swimming fish. The absorption rates were perfusion limited in gills perfused with a saline containing 2% polyvinylpyrrolidone MW 40,000 (PVP-40) as a plasma protein substitute. Replacement of PVP-40 with 2% bovine serum albumin increased the absorption rates 5-10 times, and in this case rates were not perfusion limited. Furthermore, they were not ventilation limited at ventilatory water flow rates between 0.45 and 1.5 liter/(min 100 g). Our observations suggest that the absorption rates in the presence of albumin are limited by diffusion in the epithelial cell layers. The rates measured in the perfused gills are in close agreement with those measured in vivo. We conclude that the preparation is well suited to investigate the mechanisms behind the absorption of hydrophobic compounds across fish gills and how the absorption rate is related to the physicochemical properties of the compounds, as well as to environmental factors.

Absorption↗
PubMed1995

Effects of intracerebral injections of VIP on jejunal alanine absorption and gastric acid secretion in rats.

The effects of intracerebral injections of VIP on jejunal alanine absorption and gastric acid secretion, and its association with vagal outflow were examined in Sprague-Dawley rats. Intracerebroventricular injection of VIP (2 ng) decreased significantly (P < 0.05) alanine absorption across the jejunum, whereas similar injections in vagotomized rats did not show further decrease in absorption beyond that noticed by vagotomy only. Moreover, VIP injected in the Nucleus Tractus Solitarius-Dorsal Motor Nucleus (NTS-DMN) complex (1 ng) produced also a significant inhibition of Ala absorption which was reduced but remained significant (P < 0.05) after vagotomy. Water movement was not affected by VIP injection in the lateral ventricle, while VIP injections in the NTS-DMN inhibited significantly (P < 0.05) jejunal water absorption by 10-12%. Vagotomy increased water absorption by 15-20% above control (P < 0.05) which was not altered by injecting VIP in the NTS-DMN complex. On the other hand, VIP injection in the NTS-DMN produced a 25.7% increase in gastric acid output in the first hour of the experiment followed by a non-significant decrease (P > 0.05) in the second hour. Same injections done in vagotomized animals produced similar effects to those elicited by vagotomy only. It can be suggested that NTS-DMN complex could be a site of action of VIP since injection of VIP in it produced a more pronounced inhibitory effect on water and Ala absorption than that produced by VIP injection in the LV. These effects were reduced or abolished by vagotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine↗
PubMed1985

Comparison of percutaneous absorption of fragrances by humans and monkeys.

The percutaneous absorption of two cosmetic fragrance materials, safrole and cinnamyl anthranilate, as well as of cinnamic alcohol and cinnamic acid, has been measured at occluded and non-occluded application sites. Absorption values were determined in the rhesus monkey in vivo. Absorption through human skin was measured by using excised skin in diffusion cells. Because of the insolubility in water of safrole and cinnamyl anthranilate, a nonionic surfactant solution (6% oleth 20) was used in the receptor chamber of the diffusion cell in order to facilitate the partitioning of the compounds from the skin into the receptor fluid. The relative volatility of the compounds was determined in order to aid in the interpretation of the absorption results. The greatest difference between in vivo and in vitro absorption values occurred with safrole, which was the least well absorbed and the most volatile compound. Cinnamic acid absorption through non-occluded human skin (17.8 +/- 4.9%, mean +/- SEM) was significantly lower than through monkey skin (38.6 +/- 8.3%). The values for absorption through human and monkey skin did not differ significantly for cinnamyl anthranilate (24.0 +/- 5.1% v. 26.1 +/- 2.3%) or cinnamic alcohol (33.9 +/- 7.3% v. 25.4 +/- 4.4%). Occlusion of the skin resulted in greater permeation of all of the compounds; a significant difference in permeability between the two types of skin occurred only with safrole. The fragrances were absorbed well, but their volatility must be considered in a toxicity evaluation. There was reasonable agreement between the values obtained from the studies of the human skin in vitro and the monkey skin in vivo.

Animals↗
PubMed1992

Percutaneous absorption of nicotinic acid, phenol, benzoic acid and triclopyr butoxyethyl ester through rat and human skin in vitro: further validation of an in vitro model by comparison with in vivo data.

The in vitro percutaneous absorption of three model compounds, nicotinic acid, phenol and benzoic acid, and the herbicide triclopyr butoxyethyl ester (triclopyr BEE) has been investigated in flow-through diffusion cells using skin from male Fischer 344 rats and humans. After the application of the four chemicals to the epidermal surface of unoccluded full-thickness rat skin, the absorption of each compound across the skin and into the receptor fluid at 72 hr reached 3.7 +/- 0.3, 5.7 +/- 0.6, 26.7 +/- 3.7 and 48.3 +/- 1.2% (mean +/- SD, n = 2-7) of the applied dose for triclopyr BEE, nicotinic acid, phenol and benzoic acid, respectively. After the application of the four chemicals to the epidermal surface of unoccluded full-thickness human skin, the absorption of each compound across the skin and into the receptor fluid at 72 hr was significantly (P < 0.05) less than through rat skin, reaching 0.7 +/- 0.1, 0.7 +/- 0.2, 18.8 +/- 1.3 and 37.8 +/- 6.9% (mean +/- SD, n = 2-7) of the applied dose for triclopyr BEE, nicotinic acid, phenol and benzoic acid, respectively. Occlusion of the skin surface with teflon caps often significantly (P < 0.05) enhanced the percutaneous absorption of the model compounds, although this effect was not uniform, varying with the compound under study and the skin (rat or human) used. When rat skin was occluded with teflon caps, the extent of absorption at 72 hr reached 8.6 +/- 0.8, 36.2 +/- 1.7 and 51.8 +/- 3.3% (mean +/- SD, n = 3-4) for nicotinic acid, phenol and benzoic acid, respectively. Corresponding values for human skin occluded with teflon caps were 3.3 +/- 1.6, 47.1 +/- 0.5 and 65.5 +/- 7.1% (mean +/- SD, n = 3-4). The experiments on the absorption of each model compound through rat and human skin were repeated and there was generally good agreement between the results from the two sets of experiments. The in vitro data reported compare favourably with data obtained by other workers using both in vitro and in vivo methodologies. The in vitro: in vivo correlation supports the use of the flow-through diffusion cell system as a model for the prediction of percutaneous absorption in vivo in the rat and in humans.

Absorption↗
PubMed1987

Absorption of electrolytes and water by the jejunum and colon in milk-fed lambs.

Net absorption of electrolytes (Na, Cl, K, Ca) and water from ligated loops was studied at various intestinal sites in milk-fed lambs. The unidirectional fluxes of Na across the intestinal mucosa were also investigated using 22Na. Net Na and water absorption in the mid-jejunum were about two-fold higher than in the proximal and distal jejunum and the colon descendens. With the exception of the proximal jejunum, Na and Cl absorption did not differ significantly. The unidirectional Na fluxes in both directions were much higher in the proximal and mid-jejunum than in the distal jejunum and colon descendens. K was also absorbed most efficiently from the mid-jejunum. In the colon descendens mean net K absorption was about zero. Ca absorption in the upper and mid-jejunum exceeded that of the distal jejunum and colon descendens, where the values were close to zero. The results show that in the whole jejunum of young milk-fed lambs net absorptive fluxes of Na, Cl, K, Ca and water occur, whereas the colon descendens appears to play a role only in Na, Cl and water absorption.

Animals↗
PubMed1984

Absorption of experimentally administered materials by the hepatopancreas cells of the crayfish, Procambarus clarki.

After long term starvation, the crayfish, Procambarus clarki was administered protein silver, iron lactate and olive oil, and its hepatopancreas was subsequently examined by electron microscopy. The reserve cells showed changes suggesting the absorption of these materials from the acinar lumen had taken place. In contrast, the hindgut of crayfish seemed to have no absorptive ability. In crustaceans the hepatopancreas is the largest gland in the body. The chief functions of this gland are the secretion of digestive juice into the stomach and absorption of digested food. It is also where materials which are necessary for hardening of animals that have undergone ecdysis are stored. Although these roles are commonly accepted, the absorptive ability of the gland has been rarely studied. Yonge (1924) and van Weel (1955) attempted to obtain evidence for the absorptive function of hepatopancreas cells of Nephrops norvegicus and Atya spinides using iron lactate and iron saccharate, and obtained some positive results. They used the histochemical Prussian blue test to demonstrate absorbed iron. Vonk (1960) referred to the results of a few authors who had tried to show fat deposits in reserve cells of the hepatopancreas after the administration of olive oil to the animals. But because starvation did not affect the quantity of stored fat in the hepatopancreas cells, the attempt failed to reveal the absorption of fat by the hepatopancreas. In the present paper, the authors describe the results of studies on the absorption of experimentally administered materials by hepatopancreas cells of the crayfish, Procambarus clarki, using electron microscopy.

Animals↗
PubMed1990

Ascorbic acid safety: analysis of factors affecting iron absorption.

The potential for excessive iron absorption by subjects ingesting ascorbic acid doses above the recommended dietary allowance (60 mg) was evaluated by examining published literature (24 studies, 1412 subjects) in which ascorbic acid was part of a test meal given to determine effects on iron absorption. Three parameters associated with iron absorption were identified: (1) a relatively shallow slope for the dose-response curve relating ascorbic acid dosage (1-1000 mg) and percent iron absorption; (2) no significant effect of ascorbic acid on the absorption of high (60 mg) iron doses; and (3) an inverse relationship between iron absorption and plasma transferrin saturation. Ascorbic acid did not increase the incidence of 'high' iron absorbers (greater than 2 SD from population mean) above control levels; limited data for ascorbic acid doses greater than 100 mg/d indicated no change in the distribution of iron absorption values.

Adult↗
PubMedDate not supplied

The effects of acute stress on ethanol absorption in LS and SS mice.

Previously, our laboratory demonstrated that naive long-sleep (LS) mice absorb ethanol faster than short-sleep (SS) mice when administered 6.0 g/kg ethanol intragastrically (IG). We also demonstrated that the removal of the adrenal glands results in decreased absorption in both lines of mouse. The present study was designed to assess whether acute short-term elevations of corticosterone produced by exposure to a mild stressor could also alter ethanol absorption in LS and SS mice. Because a difference in ethanol absorption rates was observed in LS mice as a function of time of day, all stress experiments were performed in the morning. CCS elevation was induced by exposure to an elevated plus-maze for 45 min. LS mice demonstrated greater CCS release in response to this stressor than SS mice. This exposure to a mild stressor produced an increase in ethanol absorption in both lines of mice receiving a 6.0 g/kg intragastric dose of ethanol. Although this effect of stress on ethanol absorption could be prevented by adrenalectomy in SS mice, adrenalectomy alone did not completely block these effects of stress on ethanol absorption in LS mice. Dexamethasome treatment at the time of adrenalectomy was required to block the effects of stress on ethanol absorption in LS mice. These results suggest that exposure to mild stressors may alter ethanol pharmacokinetic parameters but that genetic factors may play a role in this response via regulation of the hypothalamic-pituitary-adrenal axis.

Absorption↗
PubMed1995

Calcium absorption, endogenous excretion, and endocrine changes during and after long-term bed rest.

Negative calcium balance is a known consequence of bed rest, and is manifested in elevated urine and fecal calcium (Ca). Elevated fecal Ca can result from either decreased absorption, increased endogenous fecal excretion, or both. We measured the Ca absorption and endogenous fecal excretion in eight healthy male volunteers before and during 4 months of bed rest. Dual isotope (n = 6) or single isotope (n = 2) methods in conjunction with Ca balance were used to calculate true and net Ca absorption and endogenous fecal excretion. Stool Ca increased from 797 mg/day (mean intake 991 mg/day) to 911 mg/day during bed rest, whereas urine Ca excretion increased from 174 to 241 mg/day. True Ca absorption decreased from 31 +/- 7% of Ca intake pre-bed rest to 24 +/- 2% during bed rest, (p < 0.05) and returned toward pre-bed rest values within 5-6 weeks following reambulation. Endogenous fecal excretion did not change significantly, and therefore, most of the increased fecal Ca resulted from changes in absorption. However, in one individual, endogenous fecal Ca excretion was the major contributor to Ca loss. Ionized Ca and pyridinium crosslinks increased and 1,25(OH)2 vitamin D decreased during bed rest, similar to the decrease in Ca absorption; parathyroid hormone (PTH), calcitonin, serum albumin, phosphorus, and total serum Ca were unchanged. Although alkaline phosphatase, osteocalcin, and PTH were unchanged during bed rest, they were elevated during reambulation. These changes accompanied by increased Ca absorption and balance and decreased ionized and total serum Ca suggest a rebound in bone formation following immobilization.

Absorption↗
PubMed2003

A role for Ca(v)1.3 in rat intestinal calcium absorption.

Active Ca(2+) absorption through epithelial Ca(2+) channels TRPV5/6 in duodenum is activated by hyperpolarisation. However, when diet and Ca(2+) are plentiful, digestion products cause depolarisation. We therefore used homology-based PCR from a rat jejunal mucosal cDNA preparation to reveal the presence of the neuroendocrine L-type isoform Ca(v)1.3alpha(1). Immunocytochemical labelling and immunoblotting localised Ca(v)1.3 alpha(1) protein in apical membrane from proximal jejunum to mid ileum. Perfusion studies in vivo with 1.25 mM luminal Ca(2+) revealed L-type channel activity. Inhibition of glucose absorption with phloridzin strongly inhibited 45Ca(2+) absorption; absorption was inhibited by nifedipine and Mg(2+) and activated by Bay K 8644, none of which affect TRPV5/6. At 10mM Ca(2+), nifedipine inhibited 45Ca(2+) absorption with a time course similar to that at 1.25 mM Ca(2+): absorption was therefore channel-mediated rather than paracellular. We suggest that in times of dietary sufficiency, Ca(v)1.3 may mediate a significant route of Ca(2+) absorption into the body.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2004

Segment-selective absorption of lysozyme in the intestine.

Absorption of fluorescein isothiocyanate-labeled lysozyme (FITC-lysozyme) was examined in rat small intestine. Messenger RNA of megalin, an endocytic receptor for lysozyme in the kidney, was expressed in the lower but not in the upper intestine. In in situ closed loop and recirculation methods, absorption of FITC-lysozyme from the upper intestine was much higher than from the lower intestine. The absorption rate of FITC-lysozyme in the upper intestine was significantly higher than FITC-dextran and was inhibited by unlabeled lysozyme in a concentration-dependent manner. The absorption of FITC-lysozyme was also inhibited by spermine and phenylarsine oxide. These results indicate that the intestinal absorption of lysozyme is segment-selective and occurs preferentially from the upper intestine. Megalin expressed in the lower intestine appears not to have a significant role in the absorption of lysozyme. In the upper intestine, lysozyme appears to be absorbed by an endocytic pathway, and cationic charge may be important for lysozyme absorption.

Animals↗
PubMed2006

Dexamethasone increases fluid absorption via Na+/H+ exchanger (NHE) 3 activation in normal human middle ear epithelial cells.

The proper homeostasis of the liquid lining the surface of the middle ear cavity is vitally important for maintaining a fluid-free middle ear cavity. Disruption of this homeostasis leads to fluid collection in the middle ear cavity and results in otitis media with effusion. We demonstrated the molecular and functional expression of the Na+/H+ exchanger (NHE)s in normal human middle ear epithelial (NHMEE) cells. We also evaluated the role of NHEs in fluid absorption and the effect of dexamethasone on NHE function and NHE-dependent fluid absorption in NHMEE cells. Western blot analysis was performed for NHE1, -2, and -3 in NHMEE cells. The fluid absorption rate was measured after liquid application on the luminal surface of the cells. Intracellular pH (pHi) was measured using the pH-sensitive fluorescent probe bis-(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-AM. NHE activity was determined as Na+-induced pHi recovery from an acid load achieved by luminal exposure to 40 mmol/l NH4Cl. NHE1, -2 and -3 were all expressed in the NHMEE cells. The pHi recovery rate was suppressed by inhibition of NHE2 and -3 with HOE694 at concentrations greater than 50 microM. Inhibition of NHE3 with 650 microM of HOE694 or S3226 significantly decreased the fluid absorption rate. Dexamethasone increased the Na+-induced pHi recovery rate which was reversed by the inhibition of NHE3 with 650 microM of HOE694. Dexamethasone treatment up-regulated NHE3 expression in a dose-dependent manner. The fluid absorption rate was increased by treatment with dexamethasone (10(-7) M) and reversed by the inhibition of NHE3. In summary, we have shown that NHE3 are involved in the regulation of both pHi and fluid absorption on the luminal surface of NHMEE cells. Dexamethasone stimulates NHE3 expression and NHE3-dependent fluid absorption in NHMEE cells. These findings provide a new insight into mechanisms that regulate periciliary fluid and the therapeutic mechanisms behind steroid treatment of otitis media with effusion.

Absorption↗