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Biomedical subjects

M Molina

Publications and source records attributed to M Molina.

At least 91 records · Page 5Linked to original sources
PubMed1996

Incidence of Vibrio cholerae O1 diarrhea in children at the onset of cholera epidemic in periurban Lima, Peru.

OBJECTIVE: To determine the incidence of Vibrio cholerae O1-associated diarrhea in children during the onset of the 1991 cholera epidemic in Peru. METHODS: Stool cultures were obtained from children (mean age, 26 months) participating in a prospective community-based study of diarrhea in a periurban community in Lima between February and May, 1991. RESULTS: Of the 409 diarrheal episodes cultured V. cholerae O1 was isolated in 14 (3.4%) episodes. This represented an incidence of 0.11 episode per child year, higher than previously reported rates in children from endemic cholera areas. Most cases were mild; only 1 case required hospitalization. CONCLUSIONS: Our study indicates that from the beginning of this epidemic, V. cholerae O1 caused diarrhea in children as well as adults and should therefore be considered as one of the possible pathogens when children from a cholera-affected area develop diarrhea.

Bacterial Infections↗
PubMed1996

[Extrathoracic sarcoidosis with giant splenomegaly and cranial osteolysis].

Isolated extrathoracic sarcoidosis is a rare entity. We present a 25-year old woman with recurrent episodes of fever of unknown origin in the 10 years previously, with a new episode of fever with hepatosplenomegaly, abdominal adenopathies and cranial osteolysis without pulmonary or mediastinal affectation. With the suspicion of linfoproliferative disease we have resected the spleen with a weight of 1500 g. and multiple non caseous granulomata also in the liver and adenopathies. The clinical presentation is compatible with an atypical sarcoidosis without thoracic affectation and with two rare associated clinical manifestation namely giant splenomegaly and sarcoidosis of the skull.

Adult↗
PubMed1995

Glutamine transport by vesicles isolated from tumour-cell mitochondrial inner membrane.

Mitochondrial-inner-membrane vesicles, isolated from Ehrlich ascites carcinoma cells by titration with detergents, accumulated L-glutamine by a very efficient transport system. The vesicles lack any phosphate-activated glutaminase activity, allowing measurement of transport rates without interference by L-glutamine metabolism. The time course of the transport was linear for the first 60 s, reaching a steady state after 120 min. L-Glutamine transport showed co-operativity, with a Hill coefficient of 2.2; the kinetic parameters S0.5 and Vmax had values of 5 mM and 26 nmol/30 s per mg of protein respectively. The pH-dependence curve showed a bell shape, with a pH optimum about 8.0. The uptake of L-glutamine was not affected by the presence of a 50-fold molar excess of D-glutamine, L-cysteine, L-histidine, L-alanine, L-serine and L-leucine, whereas L-glutamate behaved as a poor inhibitor. The structural analogue L-glutamate gamma-hydroxamate (5mM) inhibited the net uptake by 68%; interestingly, other analogues (6-diazo-5-oxo-L-norleucine, acivicin and L-glutamate gamma-hydrazide) were ineffective. The impermeant thiol reagent p-chloromercuriphenylsulphonic acid (0.5mM) completely abolished the mitochondrial L-glutamine uptake; in contrast, other thiol reagents (mersalyl and N-ethylmaleimide) did not significantly affect the transport. These data confirm the existence of a specific transport system with high capacity for L-glutamine in the mitochondrial inner membrane, a step preceding the highly operative glutaminolysis in tumour cells.

Amino Acids↗
PubMed1995

Conformational structure of bombesin as studied by vibrational and circular dichroism spectroscopy.

Raman and Fourier transform infrared (FTIR) spectroscopies and circular dichroism (CD) have been applied to investigate the secondary structure of bombesin in the solid state and in phosphate buffer solution (pH 3.8). At concentrations around 10(-5) M, circular dichroism reveals that bombesin exists as an irregular or disordered conformation. However, the secondary structure of the peptide appears to be a mixture of disordered structure and intermolecular beta-sheets in 0.01 M sodium phosphate buffer when the peptide concentrations are higher than around 6.5 mM. The tendency of bombesin to form aggregated beta-sheet species seems to be originated mainly in the sequence of the residues 7-14, as supported by the Raman spectra and beta-sheet propensities (P beta) of the amino-acid residues. It is the hydrophobic force of this amino-acid sequence, and not a salt bridge effect, that is the factor responsible for the formation of peptide aggregates.

Amino Acid Sequence↗
PubMed1995

Ambulatory 24-hour manometric and pH metric evidence of permanent impairment of clearance capacity in patients with esophageal atresia.

Dysphagia and gastroesophageal reflux (GER) probably caused by structural disorganization of the esophagus occur frequently after repair of tracheoesophageal fistula (TEF), and the extent to which they may improve beyond childhood is not known. The aim of the present study is to assess by combined ambulatory 24-hour manometry and pH-metry the esophageal peristaltic activity and acid clearing capacity in adolescents and adults who had been operated on for TEF at birth. Twenty-two patients, aged 17.1 +/- 4.5 years (mean +/- SD), were examined with combined three-channel manometry and two-channel pH-metry followed by endoscopy and biopsy. Although they considered themselves healthy, on careful interrogation, 16 (72%) were found to have dysphagia, 13 (59%) had heartburn, 10 (45%) had foreign body impaction, and 7 (31%) had chronic respiratory tract disease. GER was detected in 12 (54%) patients (5 with histological esophagitis), 10 of whom had a pattern of prolonged nocturnal episodes with very slow clearance. All patients had diminished contractile activity with low-amplitude and short-duration waves that decreased from 0.53 +/- 0.35 waves per minute to 0.28 +/- 0.2 waves per minute during sleep. Propulsive activity was uniformly disorganized, with peristaltic sequences being few (less than 50% overall) and incomplete (above 80%). Finally, the acid-clearing capacity was nil; the proportions of ineffective sequences were above 90% for all periods considered, including sleep and mealtimes. The motor behavior of nonrefluxing and refluxing patients was identical despite the differences in esophageal acid exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Characterization of domains in the yeast MAP kinase Slt2 (Mpk1) required for functional activity and in vivo interaction with protein kinases Mkk1 and Mkk2.

MKK1/MKK2 and SLT2 (MPK1) are three Saccharomyces cerevisiae genes, coding for protein kinases, that have been postulated to act sequentially as part of the Pkc1p signalling pathway, a phosphorylation cascade essential for cell integrity. By using the 'two-hybrid system' and co-purification experiments on glutathione-agarose beads, we have shown that Slt2p interacts in vivo and in vitro with both Mkk1p and Mkk2p, thus confirming a previous suggestion based on epistasis experiments of the corresponding genes. Plasmid constructs of the SLT2 gene, deleted in the whole C-terminal non-kinase region or part of it, and therefore containing all of the conserved kinase subdomains, were still functional in complementation of the slt2 lytic phenotype and in vivo interaction with Mkk1p and Mkk2p. In contrast, the Slt2p C-terminal domain (162 residues) that carries a glutamine-rich fragment followed by a 16 polyglutamine tract, was shown to be dispensable for complementation and in vivo association with Mkk1p and Mkk2p. We have also demonstrated that the N-terminal putative regulatory domain of these two MAP kinase activators is the main region involved in the interaction with Slt2p.

Base Sequence↗
PubMed1995

[Adrenal gland insufficiency associated with primary antiphospholipid syndrome].

A 32 year old man with previously generalized convulsive episodes developed after one acute infectious process multiple venous and arterial thrombosis and an acute adrenal insufficiency probably due to bilateral adrenal hemorrhage. The clinical picture was considered to be a primary antiphospholipid syndrome with positive IgG anticardiolipin antibodies, and was successfully managed with anticoagulants and steroids.

Adrenal Gland Diseases↗