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Biomedical subjects

A Rubino

Publications and source records attributed to A Rubino.

At least 109 records · Page 6Linked to original sources
PubMed1984

Effects of loperamide on intestinal ion transport.

The synthetic opiate loperamide (LPMD) is an antidiarrheal compound which affects both intestinal motility and the transport of water and electrolytes. We have investigated its effects on ion transport in the stripped ileal mucosa of rabbits, mounted in Ussing chambers in vitro. Addition of LPMD to serosal bathing medium resulted in a dose-dependent decrement of short-circuit current (Isc). LPMD (50 microM) significantly increased net Cl absorption (JClnet) and JRnet (assumed to represent HCO3 secretion). LPMD also inhibited the Isc increments evoked either by agents that increase 3',5'-cyclic adenosine monophosphate (cAMP) content (theophylline and prostaglandin E2) or by the Ca2+ ionophore A23187; the opiate, however, did not prevent the Isc change induced by 3',5'-cyclic guanosine monophosphate (cGMP)-related agents such as 8-Br-cGMP and Escherichia coli heat-stable enterotoxin. LPMD did not alter basal or secretagogue-stimulated tissue cAMP. In contrast, LPMD caused a small increase in cGMP content of stripped ileal mucosa, but not in that of isolated enterocytes. The role of Ca2+ in LPMD action is suggested by the significantly different effect of the drug on JClnet in the presence and in the absence of Ca2+ in the serosal solution.

Animals↗
PubMed1983

In vitro effects of conalbumin on iron transport by rat intestinal mucosa.

The possible effects of conalbumin (a glycoprotein closely resembling lactoferrin) on iron transport across the brush border of intestinal cells of the rat were evaluated in vitro. Iron influx was measured in proximal and distal tracts of small intestine from either normal or iron-deprived rats, both in the presence of 1 or 10 mg/ml conalbumin and in its absence. Conalbumin did not affect iron uptake at any concentration and in any intestinal segment, either in normal or in iron-deprived animals. It was concluded that the luminal presence of conalbumin, even at a relatively high concentration, does not interfere with iron intestinal transport.

Animals↗
PubMed1979

Influx of glycyl-proline and free amino acids across intestinal brush border of phenobarbital-treated rats.

In a previous study the authors have shown that treatment with phenobarbital in the rat is followed by a generalized increase of amino acid concentration in the plasma. In order to better clarify this phenomenon, the effect of phenobarbital on intestinal protein absorption was now studied by measuring the influxes of Glycyl-L-Proline, L-Phenylalanine, L-Lysine and L-Glutamic acid across the brush border of jejunum and ileum in rats treated with phenobarbital for two or four days. No significant changes of these influxes were observed in the treated animals as compared to the controls, hence suggesting that the effect of phenobarbital on plasma levels of free amino acids is not mediated by an effect on intestinal absorption. The rate of Glycyl-Proline influx as compared to those of amino acid influxes suggests the occurrence of a carrier-mediated transport process for this dipeptide in the rat intestine as previously shown in the rabbit.

Amino Acids↗
PubMed1977

Dipeptide transport in the intestinal mucosa of developing rabbits.

Influxes of glycyl-L-proline (a dipeptide which is not hydrolysed in the membrane and is transported intact across the brush border) and of glycyl-L phenylalanine (a dipeptide which has affinity for the peptide transport system and is hydrolysed at the brush border membrane) have been studied in the small intestine of fetal, newborn and suckling rabbits. For glycyl-L-phenylalanine, transport as the intact dipeptide and 'membrane hydrolysis + amino acid transport' have been measured separately by using glycyl-L-proline and L-leucine as selective inhibitors of each pathway. For comparison, uptake of free glycine and of free phenylalanine has also been studied. The intestine of newborn rabbits is shown to have a translocation process for intact dipeptides which is saturable with a low Kt and stimulated by sodium ions, and which is not shared by free amino acids. This process resembles that described in adult animals, except that the maximal velocity is much higher in newborns. The developmental pattern of this uptake process for dipeptides differs markedly from that of free glycine, thus providing a new type of evidence for the distinction between amino acid and dipeptide transport processes. The developmental pattern of the free phenylalanine uptake process also differs from the development of the 'superficial hydrolysis + amino acid transport' component of glycl-L-phenylalanine uptake. These data suggest that the advantage of mucosal uptake of peptides, compared to the uptake of free amino acids, is much greater in the early stages of postnatal life than in the adult.

Aging↗
PubMed1977

The management of portal hypertension in cystic fibrosis.

We have found that with proper selection and preoperative preparation, a major portosystemic shunt can be done with considerable safety in a majority of cystic fibrosis patients and thus provide them with significant palliation and improved quality of life.

Child↗
PubMed1977

[Hazards involved in the working stages of a plant for the manufacture of cement-asbestos].

During a research into a factory for the manufacture of cement-asbestos pipes and slabs in which 533 workers were employed the AA. have taken an interest, over all, in the working risks related to dusts, suggesting the more suitable defence principles in various working places. We can consider the remarks, though effected in different conditions, sure in the environment conditions (of atmosphere, work and materials) in which they were carried out. More reliable results could be obtained with various measurements taken from time to time. About the entity of the dust risks and especially in relation to a priority production of preventive measures, we must consider, before all, the dusts of asbestos, then the ones of cement-asbestos and at last, the ones of cement; naturally for the dusts of the same type the greatest risk is tied to the manufactures that produce them in greater amount.

Adult↗