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Biomedical subjects

M L Silva

Publications and source records attributed to M L Silva.

At least 55 records · Page 3Linked to original sources
PubMed1993

Oral ciprofloxacin for treatment of severe infections.

Twenty adult patients with severe infections were treated with oral ciprofloxacin, 500 or 750 mg twice daily. Treatment ranged from 8 to 25 days. Efficacy was good: 14 patients (70%) were cured, four (20%) improved and there were only two (10%) failures. Tolerance was very satisfactory, the most common side-effects being mild gastrointestinal symptoms (three patients). Only one adverse laboratory result was observed: a transient rise in blood urea nitrogen and creatinine levels. None of the adverse effects led to discontinuation of treatment. Thus, ciprofloxacin presents as a promising drug for treatment of severe infections caused by susceptible organisms when ambulatorial therapy, at least during a large part of the treatment, is possible and desirable.

Administration, Oral↗
PubMed1992

Inhibition of enteropathogenic Escherichia coli adherence to HeLa cells by immune rabbit sera.

We have studied the effect of immune rabbit sera on the localized (LA) and diffuse (DA) adherence to HeLa cells of 10 enteropathogenic Escherichia coli (EPEC) strains belonging to serogroups O55, O86, O111, O119, and O142. Anti-La1 serum, obtained by rabbit immunization with an E. coli strain harboring a cloned DNA fragment from an EPEC LA plasmid, strongly inhibited the adherence of all serogroups but one (O142). Similar results were obtained with anti-LA2 serum, which is anti-O111 serum absorbed with a non-adherent O111:H- EPEC strain. In contrast, non-absorbed anti-O55 and anti-O111 sera showed an inhibitory effect mainly on the adherence of homologous strains. Except for one experiment diffuse adherence was not inhibited by any antiserum used. The inhibitory effect of immune sera on localized adherence does not seem to be correlated with plasmid curing since adherence plasmid pMS49 proved to be stable after treatment with anti-O55 and anti-O111 sera. The cross-inhibition of adherence by anti-LA sera suggests that localized adherence-related adhesins of the O55, O86, O111, and O119 strains share similar antigens.

Animals↗
PubMed1992

Late marrow allograft rejection following alpha-interferon therapy for hepatitis in a patient with paroxysmal nocturnal hemoglobinuria.

We describe a case of allograft rejection that occurred 23 months after successful bone marrow transplantation for severe aplastic anemia in a patient with paroxysmal nocturnal hemoglobinuria. The allograft rejection appears to have been induced by recombinant alpha-interferon (rINF-alpha) treatment for non-A, non-B hepatitis that developed 11 months after transplantation. During the 9 months of active hepatitis, the donor graft functioned normally; however, 3 months after rINF-alpha therapy was started, pancytopenia and a chimeric hematopoietic state developed. rINF-alpha was discontinued, cyclosporin A was reintroduced, and autologous bone marrow recovery followed. rINF-alpha treatment may be detrimental to some recipients of allogeneic bone marrow transplants.

Adult↗
PubMed1991

CD7+, CD4-/CD8- acute leukemia with t(11;14)(p15;q11) in a child.

A t(11;14)(p15;q11) was the sole chromosome abnormality observed in the malignant cells of a 10-year-old boy with acute leukemia. Morphologically, these cells were classified as L1 by the criteria of the French-American-British Working Group. Cytochemical analysis revealed that the leukemic cells were negative for Sudan Black B, periodic acid Schiff, and esterases, and positive for acid phosphatase. Immunophenotyping disclosed that the cells expressed a very immature antigenic profile [CD34+, CD7+, cytoplasmic CD3+, membrane CD3-, CD4-, and CD8-]. In spite of very intensive chemotherapy, complete remission was never induced, and the child died of progressive disease. The relationship of this case to other reported cases of acute leukemia arising from immature pluripotent hematopoietic cells is discussed.

Antigens, CD↗
PubMed1991

Stability and expression of enteropathogenic Escherichia coli adherence plasmid pMS49 in the presence of human colostrum.

Adhesion of enteropathogenic Escherichia coli (EPEC) to HeLa cells is inhibited by human colostrum. In the present study we investigated the effect of colostrum on the stability of pMS49, an EPEC adherence plasmid coding for localized adhesion and ampicillin (Ap) resistance. The plasmid was highly stable after serial passage of bacterial cultures in Tryptic Soy Broth containing 67%, 50%, 10% (v/v) or no human colostrum. A few variants (0.4%) with a low adherence were observed regardless of the treatment given. Human colostrum did not enhance their emergence. No bactericidal or bacteriostatic effect of colostrum was observed under the experimental conditions used. A specific process regulating plasmid expression is supposed to occur in EPEC strains, giving rise to variants with a lower concentration of the outer-membrane adherence-related protein and consequently lower adherence ability. This process seems to also occur for Ap-resistance genes coded in the same plasmid.

Ampicillin Resistance↗
PubMed1990

[Tuberous sclerosis associated with left ventricle rhabdomyoma].

Female infant, presenting with flexion spasms, skin hypochromatic spots and systolic ejection murmur. A clinical diagnosis of tuberous sclerosis, supported by computerized brain tomography and neurosonographic data, was made. Echocardiographic and cineangiocardiographic studies disclosed an associated tumor in left ventricle outlet. After resection of the rhabdomyoma, the patient is asymptomatic with neural manifestations controlled under valproic acid.

Echocardiography↗
PubMed1986

Plasmids coding for drug resistance and localized adherence to HeLa cells in enteropathogenic Escherichia coli O55:H- and O55:H6.

Plasmids coding for drug resistance and localized adherence (LA) to HeLa cells were found in two enteropathogenic Escherichia coli strains belonging to serotypes O55:H- and O55:H6. Strain 49-81 HSJ (O55:H-) carries two plasmids, one coding for both ampicillin resistance (Apr) and LA (pMS49). Strain 71-82 HSJ (O55:H6) harbors only one plasmid, coding for resistance to sulfadiazine, chloramphenicol, kanamycin, ampicillin, and LA (pMS71). Plasmids pMS49 and pMS71 were transferred to E. coli K-12 711 and from this strain to E. coli K-12 J53. Curing with acridine orange of an Apr LA+ transconjugant showed that both characteristics were lost simultaneously. The plasmids have a molecular weight of approximately 55 X 10(6) and are the first naturally recombinant plasmids coding for adherence and drug resistance described in enteropathogenic E. coli.

Adhesiveness↗
PubMed1985

Correlation between adherence to HeLa cells and serogroups, serotypes, and bioserotypes of Escherichia coli.

Four hundred fifty Escherichia coli strains of 45 O serogroups and subgroups and 112 serotypes were studied to determine their patterns of adherence to HeLa cells. Adherence was exhibited by strains of 17 O serogroups and subgroups, but within these groups more than one adherence pattern was frequently observed. However, within each serotype, the adherence pattern was highly consistent. Localized adherence (LA) was observed much more frequently in serotypes that we considered to be enteropathogenic E. coli serotypes (93%) than in other serotypes (14%), whereas diffuse adherence (DA) occurred predominantly among nonenteropathogenic E. coli strains. Determination of biochemical characteristics showed that within O serogroups, nonmotile strains tended to have the same behavior as motile strains with the LA adherence pattern, suggesting that they were derived from these motile strains. LA and non-LA strains of the same serotype differed biochemically. LA appears to be a property of most E. coli commonly considered to be enteropathogenic and should assist attempts to determine which E. coli are enteropathogenic and to elucidate their pathogenic mechanisms.

Adhesiveness↗
PubMed1984

Distinctive patterns of adherence of enteropathogenic Escherichia coli to HeLa cells.

We showed that Escherichia coli strains attach to HeLa cells in two different patterns. In one, the bacteria cover the whole surface of the cell (diffuse adherence), and in the other, attachment is limited to one or a few sites of the cell surface (localized adherence). Among the enteropathogenic strains, serogroups O55, O86, O11ab, O119, O125, O128ab, and O142 usually showed localized adherence when tested in the presence of D-mannose. Localized adherence was not shown either by E. coli strains isolated from urine or by enteroinvasive and enterotoxigenic E. coli strains. Some of these strains showed diffuse adherence. Some strains of serogroups O55, O111, and O119 showed both localized and diffuse adherence in the same preparation. Mannose-resistant adherence was not related to colonization factor antigens.

Adhesiveness↗
PubMed1983

Plasmid coding for drug resistance and production of heat-labile and heat-stable toxins harbored by an Escherichia coli strain of human origin.

In a study of enterotoxigenic strains of Escherichia coli isolated from children with diarrhea in São Paulo, Brazil, a new enterotoxin and antibiotic resistance plasmid that carries heat-labile toxin, heat-stable toxin, and drug resistance genes was found. This is the first such plasmid to be found in a human strain of E. coli. The plasmid is nonconjugative, has a molecular weight of at least 54 x 10(6), and is mobilized by the R plasmid present in the host strain.

Anti-Bacterial Agents↗
PubMed1978

Isolation and characterization of enterotoxin-deficient mutants of Escherichia coli.

The genes controlling the production of two types of enterotoxin of Escherichia coli, one heat-labile (LT) and the other heat-stable (ST), are found on plasmids. The absence of a direct selection procedure has made it difficult to isolate mutants affecting toxin production. However, the availability of a naturally occurring "recombinant" plasmid, carrying genes for LT and ST formation and also for resistance to tetracycline, streptomycin, and sulfonamides, made it possible to use comutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine to enrich for such mutants. We have isolated and characterized 58 LT- mutants and 7 ST- mutants. Among the LT- group we found amber mutants, temperature-sensitive mutants (most of which produce unusually heat-labile LT), and "leaky" mutants with reduced LT activity. The majority of the tested LT- mutants produced immunologically crossreacting material, in most cases in wild-type amounts. Among all 17 of the LT- mutants that could be transferred, the mutation was found to be on the plasmid. In contrast, only one of four transferrable ST- mutants appeared to be a plasmid mutant.

Bacterial Toxins↗
PubMed1978

[Glucose-6-phosphate dehydrogenase deficiency in a general hospital of Salvador, Bahia, Brazil (author's transl)].

Eight hundreds and fifteen patients of the Prof. Edgard Santos Hospital, Salvador, Bahia, were studied for G6PD deficiency by the spot test. The frequencies of deficients were 11,39% for the blacks, 7,85% for the dark mulattoes and 6,98% for the medium mulattoes. There was no difference in the percentage of deficients between out patients and patients in the wards. Also, there was no difference in the means for hematocrit, hemoglobin, frequency of hospitalization and type of disease between patients with the deficiency and the control patients. However, a past history for jaundice was significantly more frequent among the deficient patients (22,22%) than among the control patients (12,76%) (x 2(1) = 4,43; p less than 0,03). These results suggest that, in Northeastern Brazil, G6PD deficiency is not severe enough to require hospitalization but is able to cause clinically detectable jaundice.

Black People↗
PubMed1977

Susceptibility of Planorbarius metidjensis from Portugal and Spain to Schistosoma bovis from Salamanca, Spain.

The susceptibility of Planorbarius metidjensis from Portugal and Salamanca (Spain) to Schistosoma bovis from Salamanca was studied. The degree of susceptibility as measured by positivity rate, number of cercariae, pre-patent period and survival rate, showed that P. metidjensis from Portugal and Spain are very susceptible to S. bovis from Salamanca. The role of P. metidjensis as a host of S. haematobium is questioned and further studies are shown to be necessary. To determine if the disease exists in Portugal, the bovine and snail populations on the border with Salmanaca and Algarve are beginning to be screened.

Animals↗