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Biomedical subjects

S Moreno

Publications and source records attributed to S Moreno.

At least 73 records · Page 4Linked to original sources
PubMed2001

Genotoxic damage in free-living Algerian mouse (Mus spretus) after the Coto Doñana ecological disaster.

The Doñana National Park (Spain), one of the most important wildlife sites in the West of Europe, was affected (25 April 1998) by the spill of acidic waste rich in toxic metals (mainly zinc, lead, copper, etc.), arsenic and aromatic amines from the Aznalcollar mine accident. Micronuclei test with May Grunwald-Giemsa and with CREST-antikinetocore staining using DAPI as counter-staining were performed on peripheral blood erythrocytes from Algerian mice to evaluate genotoxic damage. Animals were collected in four locations each differently affected by the disaster. Higher frequencies of micronuclei and CREST-positive micronuclei were observed in the sites, which were reached by toxic sludge and contaminated water in comparison with those located within the park. The results obtained applying the two methods indicate that DAPI staining is more sensitive in detecting micronuclei. Genotoxic biomonitoring should be further carried out in the area to control the mutagenetic level in natural populations.

Animals↗
PubMed2001

Neuropsychological test performance in Aruaco Indians: an exploratory study.

A sample of 20 right-handed Aruaco Indians (12 male, 8 female; age 8-30 years) from the Sierra Nevada de Santa Marta (Colombia) participated in this study. A brief neuropsychological test battery (visuoconstructive and visuoperceptual abilities, memory, ideomotor praxis, verbal fluency, spatial abilities, concept formation) was individually administered. In addition, a handedness questionnaire was included. In some neuropsychological tests performance was virtually perfect (Recognition of Overlapped Figures and Ideomotor Praxis Ability test), whereas performance in other tests was impossible (e.g., Block Design using a time limit). It was proposed that two types of variables were significantly affecting performance: (1) educational level; and (2) cultural relevance. Some tests appeared significant and meaningful whereas others were meaningless and even impossible to understand. The appropriateness of current neuropsychological instruments for cross-cultural assessment is discussed.

Adult↗
PubMed2001

Immunocytochemical localization of acyl-CoA oxidase in the rat central nervous system.

Peroxisomal beta-oxidation, consisting of four steps catalysed by an acyl-CoA oxidase, a multifunctional protein and a thiolase, is responsible for the shortening of a variety of lipid compounds. The first reaction of this pathway is catalysed by a FAD-containing acyl-CoA oxidase, three isotypes of which have been so far recognised. Among these, straight-chain acyl-CoA oxidase (ACOX) acts on long and very long chain fatty acids, prostaglandins and some xenobiotics. We investigated ACOX localisation by means of a sensitive, tyramide based, immunocytochemical technique, thus obtaining a complete distribution atlas of the enzyme in adult rat CNS. Granular immunoreaction product was found in the cytoplasm of neuronal and glial cells, both in the perikarya and in the cell processes. ACOX immunoreactive neurons were present to variable extent, in either forebrain or hindbrain areas. Specifically, the strongest signal was detected in the pallidum, septum, red nucleus, reticular formation, nuclei of the cranial nerves, and motoneurons of the spinal cord. We then compared the ACOX immunoreactivity pattern with our previous distribution maps of other peroxisomal enzymes in the adult rat brain. While ACOX appeared to colocalise with catalase in the majority of cerebral regions, some differences with respect to d-amino acid oxidase were noted. These observations support the hypothesis of heterogeneous peroxisomal populations in the nervous tissue. The wide distribution of the enzyme in the brain is consistent with the severe and generalised neurological alterations characterising the peroxisomal disorder caused by ACOX deficiency (pseudo-neonatal adrenoleukodystrophy).

Acyl-CoA Oxidase↗
PubMed2001

Are conjunctive inferences easier than disjunctive inferences? A comparison of rules and models.

We report four experiments investigating conjunctive inferences (from a conjunction and two conditional premises) and disjunctive inferences (from a disjunction and the same two conditionals). The mental model theory predicts that the conjunctive inferences, which require one model, should be easier than the disjunctive inferences, which require multiple models. Formal rule theories predict either the opposite result or no difference between the inferences. The experiments showed that the inferences were equally easy when the participants evaluated given conclusions, but that the conjunctive inferences were easier than the disjunctive inferences (1) when the participants drew their own conclusions, (2) when the conjunction and disjunction came last in the premises, (3) in the time the participants spent reading the premises and in responding to given conclusions, and (4) in their ratings of the difficulty of the inferences. The results support the model theory and demonstrate the importance of reasoners' inferential strategies.

Cognition↗
PubMed2001

Visceral leishmaniasis in human immunodeficiency virus (HIV)-infected and non-HIV-infected patients. A comparative study.

Visceral leishmaniasis is an endemic infection in Mediterranean countries, where it has become a frequent complication of acquired immunodeficiency syndrome (AIDS). The incidence of visceral leishmaniasis is increasing in Spain due to human immunodeficiency virus (HIV)-related cases, but some aspects of its epidemiology, clinical features, and management remain unknown. In addition, no comparative clinical studies about the disease in HIV-infected and non-HIV-infected patients have been reported. During a 24-year period, 120 cases of visceral leishmaniasis were diagnosed at our institution and 80 (66%) were associated with HIV infection. The mean age at diagnosis was higher in HIV-infected that in non-HIV-infected patients (33.2 versus 23.2 yr; p = 0.002), but the male/female ratio was similar in both groups. The main risk factor for HIV infection was intravenous drug abuse (78.7%). The clinical presentation of leishmaniasis was similar in both groups, but HIV-infected patients had a lower frequency of splenomegaly than HIV-negative individuals (80.8% versus 97.4%; p = 0.02). HIV-infected patients had a greater frequency and degree of leukopenia, lymphocytopenia, and thrombocytopenia. Most of them were profoundly immunosuppressed (mean CD4+ lymphocyte count, 90 cells/mm3) at the time of diagnosis of leishmaniasis, and 53.7% had AIDS. The sensitivity of serologic studies for Leishmania was significantly lower in HIV-infected than in non-HIV-infected patients (50% versus 80%; p < 0.001), but the diagnostic yield of bone marrow aspirate (67.1% versus 79.4%) and bone marrow culture (62.9% versus 66.6%) was similar in both groups. After initial treatment, the response rate was significantly lower in HIV-infected than in non-HIV-infected individuals (54.8% versus 89.7%; p = 0.001). The relapse rate was 46.2% and 7.5%, respectively (p < 0.001). Secondary prophylaxis with antimonial compounds or amphotericin B seems to be useful in preventing relapses in HIV-infected patients. The mortality rate was higher (53.7% versus 7.5%; p < 0.001) and the median survival time shorter (25 versus > 160 mo; p < 0.001) in AIDS patients than in HIV-negative individuals. Although leishmaniasis could contribute to death in a significant number of HIV-infected patients, it was the main cause of death in only a few of them. The CD4+ lymphocyte count and the use of highly active antiretroviral therapy and secondary prophylaxis for leishmaniasis were the most significant prognostic factors for survival in AIDS patients. Visceral leishmaniasis behaves as an opportunistic infection in HIV-infected individuals and should be considered as an AIDS-defining disease.

AIDS-Related Opportunistic Infections↗
PubMed2001

Azotobacter vinelandii aldehyde dehydrogenase regulated by sigma(54): role in alcohol catabolism and encystment.

Encystment in Azotobacter vinelandii is induced by n-butanol or beta-hydroxybutyrate (BHB). We identified a gene, encoding an aldehyde dehydrogenase, that was named aldA. An aldA mutation impaired bacterial growth on n-butanol, ethanol, or hexanol as the sole carbon source. Expression of aldA increased in cells shifted from sucrose to n-butanol and was shown to be dependent on the alternative sigma(54) factor. A mutation in rpoN encoding the sigma(54) factor also impaired growth on alcohols. Encystment on n-butanol, but not on BHB, was impaired in aldA or rpoN mutants, indicating that n-butanol is not an inducer of encystment by itself but must be catabolized in order to induce encystment.

1-Butanol↗
PubMed2001

The global regulators GacA and sigma(S) form part of a cascade that controls alginate production in Azotobacter vinelandii.

Transcription of the Azotobacter vinelandii algD gene, which encodes GDP-mannose dehydrogenase (the rate-limiting enzyme of alginate synthesis), starts from three sites: p1, p2, and p3. The sensor kinase GacS, a member of the two-component regulatory system, is required for transcription of algD from its three sites during the stationary phase. Here we show that algD is expressed constitutively throughout the growth cycle from the p2 and p3 sites and that transcription from p1 started at the transition between the exponential growth phase and stationary phase. We constructed A. vinelandii strains that carried mutations in gacA encoding the cognate response regulator of GacS and in rpoS coding for the stationary-phase sigma(S) factor. The gacA mutation impaired alginate production and transcription of algD from its three promoters. Transcription of rpoS was also abolished by the gacA mutation. The rpoS mutation impaired transcription of algD from the p1 promoter and increased it from the p2 sigma(E) promoter. The results of this study provide evidence for the predominant role of GacA in a regulatory cascade controlling alginate production and gene expression during the stationary phase in A. vinelandii.

Azotobacter vinelandii↗
PubMed2001

Fission yeast mfr1 activates APC and coordinates meiotic nuclear division with sporulation.

Meiosis is the developmental program by which sexually reproducing diploid organisms generate haploid gametes. In yeast, meiosis is followed by spore morphogenesis. These two events are normally coordinated in such a way that spore formation is dependent upon completion of the meiotic nuclear divisions. Here we describe a meiosis-specific protein, mfr1, that is involved in this coordination. mfr1 is an activator of the anaphase-promoting complex (APC), which is necessary for the rapid degradation of the cdc13 cyclin at the end of meiosis II, prior to the formation of spores. An mfr1 null mutant completes meiosis II but remains with high levels of cdc13 and cdc2 kinase activity and has considerably delayed spore formation. By analogy with the mitotic cell cycle, where proteolysis and inactivation of cdc2 kinase are necessary to trigger mitotic exit and cytokinesis, we propose that at the end of meiosis rapid and timely proteolysis of cyclins is required to switch on the differentiation program that eventually leads to the formation of haploid gametes.

Amino Acid Sequence↗
PubMed2001

Flp1, a fission yeast orthologue of the s. cerevisiae CDC14 gene, is not required for cyclin degradation or rum1p stabilisation at the end of mitosis.

In Saccharomyces cerevisiae, the phosphoprotein phosphatase Cdc14p plays a central role in exit from mitosis, by promoting B-type cyclin degradation and allowing accumulation of the cyclin-dependent kinase inhibitor Sic1p. Cdc14p is sequestered in the nucleolus during interphase, from where it is released at the end of mitosis, dependent upon mitotic exit network function. The CDC14 gene is essential and loss-of-function mutants arrest at the end of mitosis. We have identified a fission yeast orthologue of CDC14 through database searches. A Schizosaccharomyces pombe flp1 (cdc fourteen-like-phosphatase) null mutant is viable, divides at a reduced size and shows defects in septation. flp1p is not the essential effector of the S. pombe septation initiation network, but may potentiate signalling of the onset of septation. In contrast to S. cerevisiae Cdc14p, flp1p is not required for the accumulation or destruction of the B-type cyclin cdc13p, the cyclin-dependent kinase inhibitor rum1p, or for dephosphorylation of the APC/C specificity factor ste9p in G1. Like its budding yeast counterpart, flp1p is restricted to the nucleolus until mitosis, when it is dispersed through the nucleus. In contrast to S. cerevisiae Cdc14p, flp1p is also present on the mitotic spindle and contractile ring. The potential roles of flp1p in cell cycle control are discussed.

Cell Cycle Proteins↗
PubMed2001

[Estimating the supply of medical specialists in Colombia by using the capture-recapture method].

OBJECTIVE: Given that it is not known how many medical doctors there are in Colombia and that, without that datum, studies of demand are simply theoretical exercises, we proposed to estimate the supply of 12 medical specialties in Colombia, using the capture-recapture technique, which was developed by zoologists to estimate wild-animal populations. METHODS: Three lists, or "captures," were used: 1) university degrees obtained abroad and graduates of postgraduate programs in Colombia, 2) members of medical societies, and 3) specialists in the principal health care enterprises. To estimate the total population we used the CAPTURE software program. RESULTS: A total of 24,910 records were obtained: 8,397 from the university records, 6,561 from the scientific societies, and 9,952 from the health care businesses. More than half of the physicians have entered the labor market during the last decade. The estimated number of physicians (with the 95% confidence interval) for each specialty was: anesthesiology, 1,753 (1,727 to 1,789); cardiology, 607 (598 to 624); dermatology, 517 (514 to 525); obstetrics and gynecology, 2,338 (2,290 to 2,400); pulmonary disease, 304 (297 to 320); neurosurgery, 324 (319 to 334); neurology, 321 (296 to 369); ophthalmology, 1,049 (1,042 to 1,061); orthopedics, 1,217 (1,212 to 1,227); otolaryngology, 634 (628 to 645); psychiatry, 855 (838 to 879); and urology, 452 (452 to 458). CONCLUSIONS: The capture-recapture technique is useful in the study of human resources. In Colombia the number of specialists doubled in less than a decade. There are specialties that are already oversupplied, such as neurosurgery. All the other specialties show growth rates that indicate a future over-supply for the health care system.

Colombia↗
PubMed2001

Risk factors for nosocomial transmission of multidrug-resistant tuberculosis due to Mycobacterium bovis among HIV-infected patients.

OBJECTIVE: To identify risk factors for transmission of multidrug-resistant tuberculosis (MDR-TB) among hospitalized human immunodeficiency virus (HIV) infected patients exposed during a nosocomial outbreak. DESIGN: Case control study. Cases were HIV-infected patients with MDR-TB due to Mycobacterium bovis (MDR-TBMb) who acquired the disease after exposure to an MDR-TBMb patient in an hospital ward. Controls were HIV-infected patients exposed to a case of MDR-TBMb in an hospital ward but who did not develop MDR-TBMb during the follow-up. RESULTS: Nineteen cases and 31 controls were included. CD4 cell counts were significantly lower among cases. Exposure in the infectious diseases ward or exposure to the index patient were associated with development of MDR-TBMb, while exposure during a single-room hospital stay and exposure in the respiratory isolation ward were associated with non-development of MDR-TBMb. A multiple regression logistic model showed that only a CD4 cell count below 50/microL and exposure to the index patient increased the risk of developing MDR-TBMb (P < 0.05). Hospitalization in a single room seemed to protect HIV-infected patients from developing nosocomial MDR-TBMb (P = 0.052). CONCLUSIONS: Over classic risk factors, such as length of exposure or sharing a room with a case, severe immunosuppression independently increases the risk of MDR-TB transmission in the context of a nosocomial MDR-TB outbreak among HIV-infected patients. This information must be considered in the management of tuberculosis outbreaks. Patients with CD4 cell counts below 50/microL should be the principal group targeted for prevention strategies in nosocomial outbreaks.

Adult↗
PubMed2000

Familial choanal atresia with maxillary hypoplasia, prognathism, and hypodontia.

We report on two sibs and a cousin with bilateral choanal atresia. At 2 months, one sib died of complications following surgical correction of her defects. We evaluated her brother and cousin at age 7 and 9 years, respectively. Both had a tall forehead, maxillary hypoplasia, prognathism, and absence of certain deciduous and permanent teeth. Psychomotor development was appropriate for age. Roentgenocephalometric analyses of several relatives showed that one grandfather of these children and two of the five uncles and aunts also had maxillary hypoplasia and/or prognathism. To our knowledge, this condition has not been described previously and may represent a newly recognized autosomal dominant condition with incomplete penetrance and variable expressivity caused by a defect of neural crest development.

Adult↗
PubMed2000

Human p8 is a HMG-I/Y-like protein with DNA binding activity enhanced by phosphorylation.

We have studied the biochemical features, the conformational preferences in solution, and the DNA binding properties of human p8 (hp8), a nucleoprotein whose expression is affected during acute pancreatitis. Biochemical studies show that hp8 has properties of the high mobility group proteins, HMG-I/Y. Structural studies have been carried out by using circular dichroism (near- and far-ultraviolet), Fourier transform infrared, and NMR spectroscopies. All the biophysical probes indicate that hp8 is monomeric (up to 1 mm concentration) and partially unfolded in solution. The protein seems to bind DNA weakly, as shown by electrophoretic gel shift studies. On the other hand, hp8 is a substrate for protein kinase A (PKA). The phosphorylated hp8 (PKAhp8) has a higher content of secondary structure than the nonphosphorylated protein, as concluded by Fourier transform infrared studies. PKAhp8 binds DNA strongly, as shown by the changes in circular dichroism spectra, and gel shift analysis. Thus, although there is not a high sequence homology with HMG-I/Y proteins, hp8 can be considered as a HMG-I/Y-like protein.

Amino Acid Sequence↗
PubMed2000

Structural and functional analysis of the cAMP binding domain from the regulatory subunit of Mucor rouxii protein kinase A.

The cAMP binding domain of the regulatory subunit (R) of Mucor rouxii protein kinase A was cloned. The deduced amino acid sequence was highly homologous in sequence and in size to the corresponding region in fungal and higher eukaryotic regulatory subunits (47-54%), but particularly homologous (62%) to Blastocladiella emersonii, a fungus classified in a different phylum. Amino acids reported to be important for interaction with cAMP, for cooperativity between the two cAMP binding domains, in the general folding of the domain, and for interaction with the catalytic subunit were conserved in all the fungal sequences. Based on either sequence or functional behavior, the M. rouxii R subunit cannot be classified as being more similar to RI or RII of mammalian systems. The M. rouxii protein sequence was modeled using as template the coordinates of the crystallized bovine regulatory subunit type Ialpha. The quality of the model is good. The two backbones could be perfectly overlapped, except for two loop regions of high divergence. The alpha helix C of domain A, proposed to have a strong interaction with the catalytic subunit, contains a leucine replacing a basic residue (arginine or lysine) commonly found in RI or RII. The domains A and B of the M. rouxii regulatory subunit were overexpressed as fusion proteins with GST. GST domain B protein was inactive. GST domain A was active; the kinetic parameters of affinity toward cAMP analogs, site selectivity, and dissociation kinetics of bound cAMP were analogous to the properties of the domain in the whole regulatory subunit.

Amino Acid Sequence↗