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Biomedical subjects

M Lluch

Publications and source records attributed to M Lluch.

At least 19 recordsLinked to original sources
PubMed1992

[Tuberculous meningitis with atypical presentation in a patient with human immunodeficiency virus infection].

A 32 years old male patient is described with infection by the human immunodeficiency virus (HIV) on stage IV C1 and with positive Ag p24 who developed tuberculous meningitis of atypical presentation. A persistent liquoral neutrophilia and low adenosindeaminase values were observed in cerebrospinal fluid of purulent appearance. The patient responded badly to tuberculostatic treatment and died. In the antibiogram carried out resistance to Mycobacterium tuberculosis was observed to rifampicine and isoniazide, two of the five drugs the patient had received. The peculiarities of the clinical form of presentation similar to purulent bacterian meningitis are discussed, and the possible influence of HIV infection and the antibiotic multiresistance observed in the bad evolution of the tuberculous meningitis which the patient developed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Methylmalonic aciduria with homocystinuria: biochemical studies, treatment, and clinical course of a Cbl-C patient.

A patient with infantile onset methylmalonic aciduria and homocystinuria (Cbl-C mutant) is described. Therapy with hydroxycobalamin, folate and vitamin B6 improved his condition. As hypomethioninaemia and homocystinaemia persisted, he was treated with intramuscular methylcobalamin, but without success. Treatment with betaine started at 25 months of age, normalized plasma methionine and elicited disappearance of homocystinaemia. Results of biochemical studies in cultured fibroblasts paralleled those described for other Cbl-C patients except that methylmalonyl-coenzyme A mutase activity in disrupted fibroblasts was in the normal range.

Betaine↗
PubMed1989

Allergic contact dermatitis from 3-(aminomethyl)-pyridyl salicylate.

2 patients with acute allergic contact dermatitis from 3-(aminomethyl)-pyridyl salicylate are described. Both patients were females with histories of urticaria and showed cross-sensitization to substances of the para group. Clinical manifestations included eczema, angioedema and respiratory effects. In 1 patient, airborne elicitation was suspected. A lymphocyte transformation test confirmed the allergy, with an extremely high response index. 35 normal controls were negative.

Aminopyridines↗
PubMed1989

Inhibition of sugar and amino acid transport across rat jejunum by cadmium, copper and mercury.

Cd2+, Cu2+ and Hg2+ (0.5 mM) inhibit the absorption of D-galactose (1 mM) across rat jejunum in vivo. The inhibition increases by 3-5 min previous exposure of the mucosa to the heavy metals, and is appreciably reversed by washing the intestinal lumen with 10 mM EDTA, and in higher proportion with 10 mM dithioerythritol. The metals do not affect the passive absorption of galactose (sugar transport blocked by 0.5 mM phlorizin), or that of L-sorbose. In vitro accumulation of D-galactose by jejunum rings is also inhibited by Cd and Cu. This inhibition is reversed by washing more readily than in vivo. The metals do not affect sugar entry into the tissues in the presence of 0.5 mM phlorizin. The inhibition of the transport component follows a non-competitive kinetics. Cd and Cu inhibit also the L-phenylalanine accumulation by the jejunum rings, but they do not modify the passive entry (in the presence of 40 mM methionine) or that in the absence of Na+. Heavy metals appear to inhibit sugar and amino acid intestinal absorption by their binding to proteins (prevailing to thiol groups) of the luminal membrane of enterocytes, which pertain or are functionally related to the corresponding Na(+)-substrate cotransport system.

Animals↗
PubMed1988

Actions of vanadate on vascular tension and sodium pump activity in cat isolated cerebral and femoral arteries.

1. The mechanisms involved in the responses induced by sodium vanadate (Va3 VO4) on cat cerebral and femoral arteries were studied. The possibility that these responses were due to Na+, K+-ATPase inhibition was investigated by measuring the effect of vanadate on [3H]-ouabain binding to arterial membrane fractions, K+-induced vasodilatation and ouabain-sensitive 86Rb+ uptake. 2. The vanadium compounds (Na3VO4, VOSO4, VCl3 and O5V3) induced similar, concentration-dependent contractions in each kind of artery, the cerebral vessels being the most sensitive to these compounds. 3. Exposure of the arteries to a low-Na+ (25 mM) solution suppressed the contraction caused by vanadate in femoral but not in cerebral arteries. 4. Vanadate-induced contractions were reduced in Ca2+-free medium but remained unaffected by 3 x 10(-6) M phentolamine, reserpine pretreatment or 3 x 10(-6) M verapamil in both kinds of artery. 5. The addition of 7.5 mM K+ to the arteries immersed in a K+-free solution induced vasodilatation, which was not modified by 10(-3) M vanadate. 6. The consecutive administration of ouabain (10(-4) M) and vanadate (10(-3) M) (or vice versa), or the simultaneous administration of both agents (10(-8) to 10(-3) M) appeared to produce an additive contraction in both types of artery. 7. Vanadate (10(-7) to 10(-3) M) did not displace the [3H]-ouabain binding to arterial membrane fractions of these arteries, whereas 10(-4) M ouabain did. 8. In both kinds of artery, total 86Rb+ uptake was reduced by ouabain (10(-8) to 10(-3) M), in a concentration-dependent manner, whereas it was not modified by vanadate (10(-8)-10(-3) M). 9. These results suggest that vanadate induces contraction in both types of artery by a mechanism unrelated to Na+, K+-ATPase inhibition. Such a mechanism is likely to be related to inhibition of the Ca2-ATPase of the cell membrane and/or the sarcoplasmic reticulum.

Animals↗
PubMed1987

Action of mercury on sugar transport across rat small intestine, in vivo.

Absorption of galactose from in vivo perfused rat jejunum was inhibited by 0.1-0.5 mM Hg2+. A few minutes' delay was required for maximal inhibition values. The effects remained after saline solution washing but were in part reversed by EDTA and in higher proportion by dithioerythritol. Absorption inhibition could be ascribed to impairment of the sugar-Na phlorizin-sensitive cotransport component: The passive apparently diffusional component that remains under 0.5 mM phlorizin and absorption of L-sorbose were unaffected by the metal. Hg action is explained as due to its binding to thiol and perhaps other chemical groups of proteins, at different depths in the membrane, which are directly or indirectly related to the sugar transport system.

Animals↗
PubMed1986

Effect of luminal Na+ on the kinetics of intestinal absorption of sugars in vivo.

The effect of sodium concentration on the absorption kinetics of glucose, galactose and 3-o-methyl-glucose in rat and hamster jejunum in vivo has been studied. In consecutive 1 min periods the total absorption and absorption in presence of 0.5 mM phlorizin were measured. The difference between them was taken as the active transport rate. The perfusion rate value was 5.6 ml X min-1 and sugar concentrations in the perfusion solution ranged from 1 to 10 mM. The results for the different sodium concentrations show a nearly common Vmax for the same sugar and animal species, while the apparent KT values increase when the sodium concentration in the lumen decreases, mimicking a pure affinity-type activation system. The absorption of sugar when solutions without Na+ are perfused, is greater than that entering passively in the presence of phlorizin. An explanation may be that appreciable amounts of endogenous Na+ find their way to the intestinal lumen in favour of the gradient, making Na+-sugar cotransport possible.

Animals↗
PubMed1979

Effect of the pH on intestinal absorption of sugars in vivo.

Influence of the pH on the absorption rate of sugars by rat intestine in vivo has been revised by means of a technique for intestinal lumen perfusion with 1 minute absorption periods. Absorption at pH 2.5, 5, 7, 8.5, and 10 has been comparied in each animal. Absorption rate of D-glucose, D-galactose and D-fructose is highest at pH 7 and decreases at the lower or higher pH values. The pH does not affect the absorption of D-arabinose. The pH effect is attributed to changes in the transport system for sugars.

Animals↗
PubMed1979

Method for successive absorptions with intestinal perfusion in vivo.

A simple technique to study intestinal absorption in vivo, a modification of that of SOLS and PONZ (34), is described. It uses a perfusion pump, with or without recycling of the solution along the intestinal lumen, and allows the carrying out of a series of successive absorption periods with high comparative value on the same intestinal segment. The technique is applied to sugar absorption in rat and hamster, but it can be extended to other substrates and other animal species. For each concentration of sugar, the intestinal absorption rate of glucose remains constant along a number of 1 min successive periods.

Animals↗
PubMed1979

Kinetics of intestinal sugar transport, in vivo.

Sugar absorption by the small intestine has been studied in rat and hamster in vivo, with luminal perfusion, during 1 minute successive periods. Transport is calculated as the difference between absorption and diffusion. The diffusion component is evaluated in the presence of phlorizin or as absorption of sorbose. The resulting KT values for glucose and galactose (rat: 7.7 and 10 mM; hamster: 10 and 14 mM) and 3-0-methyl-glucose (hamster: 25-33 mM) are quite lower than those previously obtained in vivo, but still higher than those in vitro. The physiological levels of glucose in the intestine of normally fed animals imply that the diffusion component plays an important role in the proximal regions of the small intestine, especially in rat.

Animals↗
PubMed1979

Influence of luminal Na+ on the intestinal absorption of sugars in vivo.

The effect of substituting Na+ with Tris, Li+, K+ or mannitol on the intestinal absorption of sugars, in successive periods of 1 minute duration, has been studied in rat and hamster in vivo. The absorption of 2 mM D-glucose, D-galactose, 3-0-methyl-D-glucose and D-fructose is clearly inhibited in the absence of Na+, up to 70-80%, and returns to its normal value of restoring Na+. The degree of inhibition varies with the sugar, increases on lowering Na+ concentration, reaches maximum values with mannitol as substituent, and minimum with Tris, D-arabinose absorption is not affected by Na+. These results prove once more how important Na+ is in sugar intestinal transport in vivo, while they reveal additional influences of the different substituents on the transport system.

Animals↗
PubMed1975

[Effect of various coumarins on the intestinal absorption of galactose in vivo (author's transl)].

The effect of various coumarins on the active transport of galactose by small intestine in chick and rat was studied, using the in vivo technique of sucessive absorptions. A 10(-4) M concentration of the different coumarins inhibits the absorption of galactose in the chick. This effect persists in successive absorptions without coumarin. In rat, inhibition of galactose active transport by coumarins was observed at 10(-3) M concentration.

Animals↗