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Biomedical subjects

S Moreno

Publications and source records attributed to S Moreno.

At least 181 records · Page 10Linked to original sources
PubMed1992

Pneumococcal pneumonia in adult hospitalized patients infected with the human immunodeficiency virus.

PURPOSE: To determine the attack rate; clinical, radiologic, and laboratory characteristics; and outcome of pneumococcal pneumonia in patients infected with the human immunodeficiency virus (HIV) and to compare these characteristics with those of pneumococcal pneumonia in the general population. PATIENTS AND METHODS: This is a retrospective (13-month), prospective (14-month) study. All adult hospitalized patients with pulmonary infiltrates and isolation of Streptococcus pneumoniae in blood, pleural fluid, transtracheal aspirate, or respiratory secretions obtained by plugged telescoped catheter (counts greater than 10(3) colony-forming units per milliliter) are included. MAIN RESULTS: We identified 22 HIV-infected patients and 84 HIV-seronegative patients with pneumococcal pneumonia (76% and 56%, respectively, were bacteremic). The estimated attack rate was 5.9 per 1000 for HIV-infected patients and 0.31 per 1000 for HIV-seronegative patients. Pneumococcal pneumonia was the first manifestation of HIV infection in 48% of cases. Seventy-two percent of patients younger than 40 years of age with pneumococcal pneumonia were HIV infected. No predisposing factors for pneumococcal pneumonia were identified in 76% and 2% of HIV seropositive and seronegative patients, respectively. Clinical and radiologic presentation was similar in the two populations. Of all S pneumoniae isolates, 35% were resistant to penicillin and 10% to erythromycin, without differences in the two groups. Prognosis was good, with only one infection-related death in the HIV-infected group (10 patients died in the other group). No relapses were documented in HIV-infected patients. CONCLUSION: The HIV-infected patient is at increased risk for pneumococcal pneumonia and bacteremia. Patients younger than 40 years of age who present with pneumococcal pneumonia should be considered for HIV testing, since it may be the first manifestation of HIV infection. Specific antimicrobial therapy is curative in the majority of HIV-infected patients.

AIDS Serodiagnosis↗
PubMed1992

Autophosphorylation of Mucor rouxii cAMP-dependent protein kinase and its role in holoenzyme activation.

Two phosphoproteins of 53,000 and 63,000 mol. wt detected in partially purified preparations of Mucor rouxii cAMP-dependent protein kinase submitted to phosphorylation conditions with [gamma-32P]ATP are demonstrated to be the result of the autophosphorylation of its regulatory subunit, according to the following criteria: (1) linearity of phosphate incorporation with enzyme sample; (2) independence of phosphate incorporation on temperature; (3) correlation of the phosphoproteins with enzymatic activity in a DEAE-Sepharose chromatography; (4) specific elution of the phosphorylated proteins from cAMP-agarose; (5) phosphorylation of the purified regulatory subunit. Antibodies specific against Mucor regulatory subunit detected an intact subunit of 72,000 mol. wt in crude extracts. Autophosphorylation of the fungal protein kinase A promotes activation of the holoenzyme by cAMP since: (1) under conditions of partial activation, increase of activity is observed when using the phosphoform of the enzyme; (2) release of free catalytic subunit from cAMP-agarose is enhanced when the holoenzyme is previously phosphorylated.

Adenosine Triphosphate↗
PubMed1992

Phenotype of a Rhizobium leguminosarum ntrC mutant.

A Tn5 insertion mutant, strain CFN2012, of Rhizobium leguminosarum biovar phaseoli devoid of glutamine synthetase II (GSII) activity was analysed. It was shown to contain Tn5 within an 11-kb BamHI DNA fragment, which was isolated (pSM261) from the wild-type strain and, when introduced into strain CFN2012, was shown to complement the absence of GSII activity. The DNA sequence of the corresponding region from the wild-type allele revealed the presence of an ntrC regulatory gene, and restriction analysis indicated that the mutant allele carried the Tn5 insertion within it. Further analysis of strain CFN2012 indicated that this mutant has reduced levels of the PII regulatory protein and that, in contrast to ntrC mutants of other Rhizobiaceae, it grows on nitrate as the sole nitrogen source.

Bacterial Proteins↗
PubMed1992

Group B Streptococcus: a cause of urinary tract infection in nonpregnant adults.

Group B Streptococcus (GBS) is a well-known cause of infection in the perinatal and puerperal periods, but its role as a urinary tract pathogen of adults in nonobstetric situations has not yet been defined. We carried out a prospective 19-month study of all nonpregnant adult patients with significant GBS bacteriuria. This microorganism accounted for 2% of positive urine cultures. Our series included 60 patients, 85% of whom were women and 95% of whom had at least one underlying condition. Urinary tract abnormalities (60%) and chronic renal failure (27%) were among the most frequent underlying problems. The infection was community acquired in 65% of cases. Clinical manifestations were related equally to the upper and the lower urinary tract (37% and 38% of cases, respectively). The clinical outcome was poor in 18% of episodes despite treatment. All isolates were sensitive to all antibiotics tested except gentamicin. We conclude that GBS is a significant urinary pathogen in nonpregnant adults and that its presence signals a need for screening for urinary tract abnormalities.

Adult↗
PubMed1991

Phosphorylation at Thr167 is required for Schizosaccharomyces pombe p34cdc2 function.

Eukaryotic cell cycle progression requires the periodic activation and inactivation of a protein-serine/threonine kinase which in fission yeast is encoded by the cdc2+ gene. The activity of this gene product, p34cdc2, is controlled by numerous interactions with other proteins and by its phosphorylation state. In fission yeast, p34cdc2 is phosphorylated on two sites, one of which has been identified as Tyr15. Dephosphorylation of Tyr15 regulates the initiation of mitosis. To understand more completely the regulation of p34cdc2 kinase activity, we have identified the second site of phosphorylation as Thr167, a residue conserved amongst all p34cdc2 homologues. By analysing the phenotypes of cells expressing various position 167 mutations and performing in vitro experiments, we establish that Thr167 phosphorylation is required for p34cdc2 kinase activity at mitosis and is involved in the association of p34cdc2 with cyclin B. Dephosphorylation of Thr167 might also play a role in the exit from mitosis.

Amino Acid Sequence↗
PubMed1991

Leuconostoc species as a cause of bacteremia: two case reports and a literature review.

Two new cases of significant bacteremia caused by Leuconostoc spp. are reported and five others described in the literature are reviewed. Four of the seven patients were under one year old and presented with prolonged diarrhea related to gastrointestinal disorders. The remaining three patients were over 50 years of age and being treated in intensive care units. Six patients had nosocomially acquired catheter-related bacteremia. Leuconostoc spp. are naturally resistant to vancomycin, and five patients had received this antibiotic for prior bacteremia caused by methicillin-resistant staphylococci. The majority of patients presented with fever without severe complications. Penicillin is the treatment of choice and there is no report of any death directly attributable to infection by these microorganisms. Infection with Leuconostoc spp. should be suspected if "vancomycin-resistant streptococci" are isolated from the blood, and recorded as a potential cause of bacteremia in patients with indwelling intravenous catheters.

Age Factors↗
PubMed1991

Latent Haemophilus influenzae pneumonia in patients infected with HIV.

Pneumonia caused by common pyogenic bacteria occurs frequently in HIV-infected patients. Its clinical presentation has been described as being similar to that seen in non-immunosuppressed hosts but clearly different to that of opportunistic pneumonias. An atypical presentation has rarely been seen. In a 10-month period, we saw 12 HIV-infected patients who presented with Haemophilus influenzae pneumonia which was clinically and radiologically indistinguishable from Pneumocystis carinii pneumonia. Ten of the patients were intravenous drug users and were in different stages of HIV disease. The clinical picture was characterized by a prolonged course (median 4 weeks), non-productive cough, dyspnoea, and absence of findings usually present in bacterial pneumonia. Laboratory data frequently showed absence of leukocytosis, increased lactate dehydrogenase levels, hypoxaemia, and decreased CD4+ cell counts. All presented with interstitial or mixed bilateral infiltrates. Resistance to ampicillin and trimethoprim-sulphamethoxazole were each found in seven cases. Eleven patients were cured with antibiotic therapy, although five relapsed. H. influenzae pneumonia should be considered in HIV-infected patients who present with pulmonary symptoms and bilateral infiltrates of subacute or chronic onset. Clinical resolution of pneumonia is the usual outcome, but recurrences of infection are frequent.

Adult↗
PubMed1991

Formation of Rhizobium phaseoli symbiotic plasmids by genetic recombination.

We report here the formation of symbiotic plasmids (pSyms), by genetic recombination between rearranged pSyms, which lack symbiotic information, and resistance plasmids carrying parts of different symbiotic plasmids (R's). This recombination was found to occur both between plasmids derived from different Rhizobium phaseoli isolates, and between plasmids derived from strains obtained from the same original isolate. We also present evidence on the formation of a functional symbiotic plasmid by recombination of an R', carrying nif and nod genes from strain CFN42, and an indigenous plasmid present in this strain (pCFN42e), which was thought to be unrelated to its symbiotic plasmid (pCFN42d). These data are discussed with respect to the stability and transfer of Rhizobium symbiotic information.

Drug Resistance, Microbial↗
PubMed1990

Complementation of the mitotic activator, p80cdc25, by a human protein-tyrosine phosphatase.

The onset of M phase requires the activation of the pp34 protein kinase in all eukaryotes thus far examined. In Schizosaccharomyces pombe, pp34 is phosphorylated on Tyr15, and dephosphorylation of this residue regulates the initiation of mitosis. In this study, it is shown that dephosphorylation of Tyr15 triggered activation of the pp34-cyclin complex from fission yeast, that a human protein-tyrosine phosphatase can catalyze this event both in vitro and in vivo, and that activation of fission yeast pp34 does not require threonine dephosphorylation. The complementary DNA that encoded the tyrosine phosphatase replaced the mitotic activator p80cdc25, closely associating the cdc25(+)-activating pathway with tyrosine dephosphorylation of pp34.

Cell Cycle Proteins↗
PubMed1990

[Mucormycosis. The disease spectrum in 13 patients].

Mucormycosis is an uncommon infection caused by fungi of the order Mucorales. During an 8-year period, mucormycosis was diagnosed in 13 patients from three Madrid hospitals. There were 8 males and 5 females, with ages ranging from 21 to 75 years (mean 45 years). There were several underlying diseases, and 4 patients had more than one. Five had diabetes mellitus, 4 chronic renal failure, 2 acute myeloblastic leukemia, 2 were narcotic abusers and were infected by the human immunodeficiency virus (HIV), 1 had non-Hodgkin's lymphoma, 1 was a carrier of a renal allograft and 1 had systemic necrotizing vasculitis. There were different clinical presentations: rhino-orbital in 3, paranasal in 2, cutaneous in 2, pulmonary in 2, primary cerebral in 2, rhinocerebral in 1, and peritoneal in 1. The diagnosis was made during the first week in 6 patients, in the second week in 4, and it was delayed for more than one month in 2. Fresh examination of clinical samples was carried out in 3 patients and hyphae were visualized in all 3. Cultures were taken in 10 patients and they were positive in 7. All isolates were identified as Rhizopus sp. One patient died within 24 hours without being treated, 12 were treated with amphotericin B and 9 received surgical therapy. Six patients (46%) died. The involvement of central nervous system and the absence of surgical therapy were associated with a poor outcome. These results indicate that mucormycosis can develop in several clinical contexts and has a varying clinical presentation. It is a potentially curable infections when early diagnosed and appropriately treated.

Adult↗
PubMed1990

Purification and characterization of the invertase from Schizosaccharomyces pombe. A comparative analysis with the invertase from Saccharomyces cerevisiae.

Invertase (EC 3.2.1.26) was purified to homogeneity from exponentially growing cells of Schizosaccharomyces pombe fully de-repressed for synthesis of the enzyme, and was shown to be a high-molecular-mass glycoprotein that can be dissociated in the presence of 8 M-urea/1% SDS into identical subunits with an apparent molecular mass of 205 kDa. The carbohydrate moiety, accounting for 67% of the total mass, is composed of equimolar amounts of mannose and galactose. There is a small amount of glucosamine, which is probably involved in the linkage to the protein moiety, since the enzyme is sensitive to treatment with endoglycosidase H. The composition of the carbohydrate moiety resembles that found in higher-eukaryotic glycoproteins and differs from glycoproteins found in Saccharomyces cerevisiae. The protein portion of each subunit is a polypeptide of molecular mass 60 kDa, very similar to the invertase of Sacch. cerevisiae. Both proteins cross-react with antibodies raised against the protein fractions of the other, indicating that the two enzymes are similar.

Carbohydrates↗
PubMed1990

Regulation of mitosis by cyclic accumulation of p80cdc25 mitotic inducer in fission yeast.

The coordination of somatic cell division with cell size must be accomplished by the accumulation of mitotic inducers or the dilution, in the course of cell growth, of mitotic inhibitors. In fission yeast (Schizosaccharomyces pombe), cell size at mitosis is determined by expression of the cdc25+ and nim1+ inducer genes and of the inhibitor gene wee1+, which between them regulate the M-phase protein kinase p34cdc2. We now report that both the phosphoprotein product of cdc25+ (p80cdc25, with apparent relative molecular mass 80,000) and the corresponding messenger RNA increase in concentration as cells proceed through interphase, peaking at mitosis. We propose that the cell-cycle timing of mitosis in somatic cells is regulated by the cyclic accumulation of the cdc25 mitotic inducer, which on reaching a critical level results in activation of p34cdc2 protein kinase. Accumulation of this inducer could play a part in coordinating cell division with growth.

Cell Cycle Proteins↗
PubMed1990

A previously unrecognized glutamine synthetase expressed in Klebsiella pneumoniae from the glnT locus of Rhizobium leguminosarum.

Using glnT DNA of Rhizobium meliloti as a hybridization probe we identified a R. leguminosarum biovar phaseoli (R. l. phaseoli) locus (glnT) expressing a glutamine synthetase activity in Klebsiella pneumoniae. A 2.2 kb DNA fragment from R. l. phaseoli was cloned to give plasmid pMW5a, which shows interspecific complementation of a K. pneumoniae glnA mutant. The cloned sequence did not show cross-hybridization to glnA or glnII, the genes coding for two glutamine synthetase isozymes of Rhizobium spp. While in previous reports on glnT of R. meliloti and Agrobacterium tumefaciens no glutamine synthetase activity was detected, we do find activity with the glnT locus of R. l. phaseoli. The glutamine synthetase (GSIII) activity expressed in a K. pneumoniae glnA strain from pMW5a shows a ratio of biosynthetic to transferase activity 10(3)-fold higher than that observed for GSI or GSII. GSIII is similar in molecular weight and heat stability to GSI.

Cloning, Molecular↗