PubMed Health⌕ Search

Biomedical subjects

J M González

Publications and source records attributed to J M González.

At least 19 recordsLinked to original sources
PubMed2006

Novel chemolithotrophic, thermophilic, anaerobic bacteria Thermolithobacter ferrireducens gen. nov., sp. nov. and Thermolithobacter carboxydivorans sp. nov.

Three thermophilic strains of chemolithoautotrophic Fe(III)-reducers were isolated from mixed sediment and water samples (JW/KA-1 and JW/KA-2(T): Calcite Spring, Yellowstone N.P., WY, USA; JW/JH-Fiji-2: Savusavu, Vanu Levu, Fiji). All were Gram stain positive rods (approximately 0.5 x 1.8 microm). Cells occurred singly or in V-shaped pairs, and they formed long chains in complex media. All utilized H(2) to reduce amorphous iron (III) oxide/hydroxide to magnetite at temperatures from 50 to 75 degrees C (opt. approximately 73 degrees C). Growth occurred within the pH(60C) range of 6.5-8.5 (opt. pH(60C) 7.1-7.3). Magnetite production by resting cells occurred at pH(60C) 5.5-10.3 (opt. 7.3). The iron (III) reduction rate was 1.3 mumol Fe(II) produced x h(-1) x ml(-1) in a culture with 3 x 10(7) cells, one of the highest rates reported. In the presence or absence of H(2), JW/KA-2(T) did not utilize CO. The G + C content of the genomic DNA of the type strain is 52.7 +/- 0.3 mol%. Strains JW/KA-1 and JW/KA-2(T) each contain two different 16S rRNA gene sequences. The 16S rRNA gene sequences from JW/KA-1, JW/KA-2(T), or JW/JH-Fiji-2 possessed >99% similarity to each other but also 99% similarity to the 16S rRNA gene sequence from the anaerobic, thermophilic, hydrogenogenic CO-oxidizing bacterium 'Carboxydothermus restrictus' R1. DNA-DNA hybridization between strain JW/KA-2(T) and strain R1(T) yielded 35% similarity. Physiological characteristics and the 16S rRNA gene sequence analysis indicated that the strains represent two novel species and are placed into the novel genus Thermolithobacter within the phylum 'Firmicutes'. In addition, the levels of 16S rRNA gene sequence similarity between the lineage containing the Thermolithobacter and well-established members of the three existing classes of the 'Firmicutes' is less than 85%. Therefore, Thermolithobacter is proposed to constitute the first genus within a novel class of the 'Firmicutes', Thermolithobacteria. The Fe(III)-reducing Thermolithobacter ferrireducens gen. nov., sp. nov. is designated as the type species with strain JW/KA-2(T) (ATCC 700985(T), DSM 13639(T)) as its type strain. Strain R1(T) is the type strain for the hydrogenogenic, CO-oxidizing Thermolithobacter carboxydivorans sp. nov. (DSM 7242(T), VKM 2359(T)).

Anti-Bacterial Agents↗
PubMed2006

Evaluation of IFN-gamma production by CD8 T lymphocytes in response to the K1 peptide from KMP-11 protein in patients infected with Trypanosoma cruzi.

The cellular response mediated by MHC class I restricted CD8+ T cells has been shown to be crucial in the control of Chagas disease. The K1 peptide derived from T. cruzi KMP-11 protein has a high binding affinity to the HLA-A*0201 molecule. Nevertheless, it is not known whether this peptide is processed and displayed as an MHC class I epitope during natural infection by T. cruzi. The aim of this study was to evaluate, by ELISPOT assay, the ability of K1 peptide to activate CD8+ T lymphocytes to produce IFN-gamma. Therefore, CD8+ T lymphocytes from 22 HLA-A*0201+ individuals, 12 chronic chagasic patients and 10 uninfected controls, were analysed. The results revealed that two of the chagasic patients had IFN-gamma-secreting CD8+ T cells that were able to respond to K1 peptide with a relative frequency of 110 and 230 per million CD8+ T cells. In contrast, none of HLA-A*0201+ uninfected controls responded to K1 peptide. Responses to HLA-A*0201 restricted peptide from the influenza matrix protein were found in six chagasic patients and four uninfected controls with an average frequency of 175 and 111 cells per million CD8+ T cells, respectively. Moreover, a flow cytometric assay for degranulation showed that chagasic responders had K1-specific cytotoxic CD8+ T cells. It is shown here for the first time that the K1 peptide is efficiently processed, presented and recognized by CD8+ T lymphocytes during the natural course of Chagas disease.

Adult↗
PubMed2005

Phosphorylation and subcellular localization of transmissible gastroenteritis virus nucleocapsid protein in infected cells.

The nucleocapsid (N) protein is the only phosphorylated structural protein of the coronavirus Transmissible gastroenteritis virus (TGEV). The phosphorylation state and intracellular distribution of TGEV N protein in infected cells were characterized by a combination of techniques including: (i) subcellular fractionation and analysis of tryptic peptides by two-dimensional nano-liquid chromatography, coupled to ion-trap mass spectrometry; (ii) tandem mass-spectrometry analysis of N protein resolved by SDS-PAGE; (iii) Western blotting using two specific antisera for phosphoserine-containing motifs; and (iv) confocal microscopy. A total of four N protein-derived phosphopeptides were detected in mitochondria-Golgi-endoplasmic reticulum-Golgi intermediate compartment (ERGIC)-enriched fractions, including N-protein phosphoserines 9, 156, 254 and 256. Confocal microscopy showed that the N protein found in mitochondria-Golgi-ERGIC fractions localized within the Golgi-ERGIC compartments and not with mitochondria. Phosphorylated N protein was also present in purified virions, containing at least phosphoserines 156 and 256. Coronavirus N proteins showed a conserved pattern of secondary structural elements, including six beta-strands and four alpha-helices. Whilst serine 9 was present in a non-conserved domain, serines 156, 254 and 256 were localized close to highly conserved secondary structural elements within the central domain of coronavirus N proteins. Serine 156 was highly conserved, whereas no clear homologous sites were found for serines 254 and 256 for other coronavirus N proteins.

Amino Acid Sequence↗
PubMed2003

A comparative sequence analysis to revise the current taxonomy of the family Coronaviridae.

The Coronaviridae family, comprising the Coronavirus and Torovirus genera, is part of the Nidovirales order that also includes two other families, Arteriviridae and Roniviridae. Based on genetic and serological relationships, groups 1, 2 and 3 were previously recognized in the Coronavirus genus. In this report we present results of comparative sequence analysis of the spike (S), envelope (E), membrane (M), and nucleoprotein (N) structural proteins, and the two most conserved replicase domains, putative RNA-dependent RNA polymerase (RdRp) and RNA helicase (HEL), aimed at a revision of the Coronaviridae taxonomy. The results of pairwise comparisons involving structural and replicase proteins of the Coronavirus genus were consistent and produced percentages of sequence identities that were distributed in discontinuous clusters. Inter-group pairwise scores formed a single cluster in the lowest percentile. No homologs of the N and E proteins have been found outside coronaviruses, and the only (very) distant homologs of S and M proteins were identified in toroviruses. Intragroup sequence conservation was higher, although for some pairs, especially those from the most diverse group 1, scores were close or even overlapped with those from the intergroup comparisons. Phylogenetic analysis of six proteins using a neighbor-joining algorithm confirmed three coronavirus groups. Comparative sequence analysis of RdRp and HEL domains were extended to include arterivirus and ronivirus homologs. The pairwise scores between sequences of the genera Coronavirus and Torovirus (22-25% and 21-25%) were found to be very close to or overlapped with the value ranges (12 to 22% and 17 to 25%) obtained for interfamily pairwise comparisons, but were much smaller than values derived from pairwise comparisons within the Coronavirus genus (63-71% and 59-67%). Phylogenetic analysis confirmed toroviruses and coronaviruses to be separated by a large distance that is comparable to those between established nidovirus families. Based on comparison of these scores with those derived from analysis of separate ranks of several multi-genera virus families, like the Picornaviridae, a revision of the Coronaviridae taxonomy is proposed. We suggest the Coronavirus and Torovirus genera to be re-defined as two subfamilies within the Coronavirdae or two families within Nidovirales, and the current three informal coronavirus groups to be converted into three genera within the Coronaviridae.

Conserved Sequence↗
PubMed2003

[Delays in the diagnosis of lung cancer].

OBJECTIVE: To study the clinical and demographic factors associated with delays in the diagnosis of lung cancer. PATIENTS AND METHODS: A 2-year prospective study of patients admitted to the respiratory medicine ward with a suspected diagnosis of lung cancer. We studied demographic factors, health care received, place of residence, and delays in carrying out diagnostic procedures. The following diagnostic time periods were defined: consultation (from first symptom to first medical visit), middle period (from first medical visit to hospital admission) and diagnostic (from hospital admission to histological diagnosis and clinical staging). RESULTS: One hundred thirteen patients with a mean age of 65 years (range, 36-90), 103 men and 10 women, were studied. The most frequent symptoms leading to consultation were coughing (10.6%), hemoptysis (19.5%), chest pain (26.5%), and shortness of breath (9.7%). First visits were to a primary care physician for 72%, to the hospital emergency room for 22%, or to a pulmonologist for 6%. Forty-four percent of the patients visited the doctor 2 or 3 times. The mean SD, numbers of days for the different time periods were as follows: consultation, 30.3 60; diagnosis, 18.6 19; middle period 37.9 63. The mean total time from first symptom to diagnosis was 85.7 87 days. The middle period, the time in hospital until diagnosis, and the total time were shorter when patients were referred by the primary care physician to the emergency room or were directly admitted to the hospital (P<.001). Only 25.7% of the staged lung cancers were operable. CONCLUSIONS: Delays in lung cancer diagnosis are long. The attitudes of primary care physicians and their relations with specialized care providers are crucial for reducing delays.

Adult↗
PubMed2003

[Optimization of an individualized LASIK surgery. Geometric ray tracing model].

PURPOSE: To develop an objective calculation method that is able to provide a customized surgical correction that allows the patient to reach the emmetropia and the maximum visual acuity after the surgery. METHODS: The study included 187 eyes with myopia or myopic astigmatism that underwent LASIK. The optical characterization of each eye was developed by a complete theoretical model based in Le Grand eye, in which the measured values of radii and thicknesses of the different surfaces have been substituted. By means of a geometric ray tracing, the surgery has been simulated by changing the anterior corneal radius and the corneal thickness within the optical zone to obtain its influence in the ocular image and the visual acuity. We considered the surgery to be < > when the residual equivalent refraction was between 0 and +0.5 D. RESULTS: An interval for the final corneal radius is proposed for each eye in order to reach the best visual acuity (optimal interval). The position of the post-surgical radius in this interval has been related with the success of the surgical process. CONCLUSIONS: An objective method for LASIK has been proposed: i) it calculates a personalized surgical plan that allows the patient to reach the best visual quality, and ii) it can be used as a reference by the surgeon to design his nomogram and to decrease his learning curve.

Adult↗
PubMed2001

Disseminated infection and colonization by Scedosporium prolificans: a review of 18 cases, 1990-1999.

Scedosporium prolificans infection was analyzed in 18 patients from whom the fungus was isolated during the period 1990-1999. Of these 18 patients, 12 had some predisposing factor and either unconfirmed infection or colonization, and 6 patients had confirmed disseminated infection: 4 patients with leukemia died, 1 patient with breast cancer who underwent autologous bone marrow transplantation survived, and 1 patient with advanced acquired immunodeficiency syndrome died, although the fungal infection did not seem to affect his clinical symptoms.

Adult↗
PubMed2001

Cloning and sequence analysis of the LEU2 homologue gene from Pichia anomala.

The Pichia anomala LEU2 gene (PaLEU2) was isolated by complementation of a leu2 Saccharomyces cerevisiae mutant. The cloned gene also allowed growth of a Escherichia coli leuB mutant in leucine-lacking medium, indicating that it encodes a product able to complement the beta-isopropylmalate dehydrogenase deficiency of the mutants. The sequenced DNA fragment contains a complete ORF of 1092 bp, and the deduced polypeptide shares significant homologies with the products of the LEU2 genes from S. cerevisiae (84% identity) and other yeast species. A sequence resembling the GC-rich palindrome motif identified in the 5' region of S. cerevisiae LEU2 gene as the binding site for the transcription activating factor encoded by the LEU3 gene was found at the promoter region. In addition, upstream of the PaLEU2 the 3'-terminal half of a gene of the same orientation, encoding a homologue of the S. cerevisiae NFS1/SPL1 gene that encodes a mitochondrial cysteine desulphurase involved in both tRNA processing and mitochondrial metabolism, was found. The genomic organization of the PaNFS1-PaLEU2 gene pair is similar to that found in several other yeast species, including S. cerevisiae and Candida albicans, except that in some of them the LEU2 gene appears in the reverse orientation.

3-Isopropylmalate Dehydrogenase↗
PubMed2001

Sociodemographic factors and trends on overweight prevalence in children and adolescents in Aragón (Spain) from 1985 to 1995.

From 1985 to 1995, the Aragón School Health Examination Surveys staff has surveyed the whole population of children (age 6-7 years) and adolescents (age 13-14 years). A total of 90,997 children (age 6-7 years) were examined in the nine cross-sectional surveys conducted between 1985 and 1995. A total of 106,284 adolescents (age 13-14 years) were also examined. We defined overweight when the body mass index was > or = 95th percentile. The measure of association between overweight and the other variables studied was the odds ratio, which was calculated by logistic regression. In the children and adolescents studied, the probability to be overweight was higher in the rural than in the urban areas. In the adolescents, the probability to be overweight was higher in the public than in the private schools. Our results also show a significant increase in the prevalence of overweight children in the region of Aragón (Spain) during the 1985-1995 decade, especially in males. Prevention of overweight in the populations at risk would help reduce social inequality in health, a major challenge for public health policy.

Adolescent↗
PubMed2001

Determination of physical properties of bitumens by use of near-infrared spectroscopy with neural networks. Joint modelling of linear and non-linear parameters.

The fact that bitumens behave as non-Newtonian fluids results in non-linear relationships between their near-infrared (NIR) spectra and the physico-chemical properties that define their consistency (viz. penetration and viscosity). Determining such properties using linear calibration techniques [e.g. partial least-squares regression (PLSR)] entails the previous transformation of the original variables by use of non-linear functions and employing the transformed variables to construct the models. Other properties of bitumens such as density and composition exhibit linear relationships with their NIR spectra. Artificial neural networks (ANNs) enable modelling of systems with a non-linear property-spectrum relationship; also, they allow one to determine several properties of a sample with a single model, so they are effective alternatives to linear calibration methods. In this work, the ability of ANNs simultaneously to determine both linear and non-linear parameters for bitumens without the need previously to transform the original variables was assessed. Based on the results, ANNs allow the simultaneous determination of several linear and non-linear physical properties typical of bitumens.

Journal Article↗
PubMed2001

Rigid gas permeable contact lens and corneal topography.

We investigated the effect of high Dk daily wear rigid gas permeable contact lenses on corneal topography. Eight young myopic subjects wore hard contact lenses for 21 days. Corneal topography was monitored using the EyeSys system. It was measured every day during the next 21 days after the fitting. We recorded the corneal radius of curvature at 16 peripheral points approximately 1, 2, 3 and 4 mm along the four principal meridians (nasal, superior, inferior and temporal). Our study showed that daily wear RGP Forum 210 does not produce significant alterations of the corneal curvature as a function of time.

Adult↗
PubMed2001

Relevance of 99mTc-MIBI rest uptake, ejection fraction and location of contractile abnormality in predicting myocardial recovery after revascularization.

The aim of this study was to analyse the influence of rest technetium-99m-methoxy-isobutyl-isonitrile (99mTc-MIBI) uptake, left ventricular ejection fraction (EF) and dysfunctional location in the prediction of myocardial viability. Rest 99mTc-MIBI single photon emission computed tomography (SPECT) was analysed in 82 patients (59+/-9 years, 70 men, 12 women) with one or more segments showing severe hypokinesia, akinesia or dyskinesia who had undergone coronary revascularization. Before and within 3-6 months after the revascularization, gated blood pool scintigraphy was performed. In the post-revascularization control, contractile recovery was observed in 48.7% (155/318) of the segments with severe hypokinesia, akinesia or dyskinesia. Significant increases in sensitivity (53%, 72% and 91%, P<0.0001) and negative predictive value (62%, 68% and 79%, P = 0.01) were observed with decreasing rest uptake 99mTc-MIBI levels of 50%, 40% and 30%, respectively. The decrease in specificity was also significant (67%, 53% and 32%, P<0.0001). The negative predictive value was higher than the positive predictive value mainly in patients with EF < or = 0.35 and with anterior dysfunction. In logistic regression analysis, uptake levels and EF were independent variables that influenced sensitivity and specificity. The negative predictive value was influenced by EF and the positive predictive value only by dysfunctional location. This study suggests that the negative predictive value of 99mTc-MIBI SPECT is higher than the positive predictive value, mainly in patients with EF < or = 0.35, and that the rest uptake level, EF and dysfunctional location are factors that must be considered when results of 99mTc-MIBI SPECT are analysed.

Aged↗
PubMed2001

Carboxydobrachium pacificum gen. nov., sp. nov., a new anaerobic, thermophilic, CO-utilizing marine bacterium from Okinawa Trough.

A new anaerobic, thermophilic, CO-utilizing marine bacterium, strain JMT, was isolated from a submarine hot vent in Okinawa Trough. Cells of strain JMT were non-motile thin straight rods, sometimes branching, with a cell wall of the Gram-positive type, surrounded with an S-layer. Chains of three to five cells were often observed. The isolate grew chemolithotrophically on CO, producing equimolar quantities of H2 and CO2 (according to the equation CO+H2O-->CO2+H2) and organotrophically on peptone, yeast extract, starch, cellobiose, glucose, galactose, fructose and pyruvate, producing H2, acetate and CO2. Growth was observed from 50 to 80 degrees C with an optimum at 70 degrees C. The optimum pH was 6.8-7.1. The optimum concentration of sea salts in the medium was 20.5-25.5 g l(-1). The generation time under optimal conditions was 7.1 h. The DNA G+C content was 33 mol %. Growth of isolate JMT was not inhibited by penicillin, but ampicillin, streptomycin, kanamycin and neomycin completely inhibited growth. The results of 16S rDNA sequence analysis revealed that strain JMT belongs to the Thermoanaerobacter phylogenetic group within the Bacillus-Clostridium subphylum of Gram-positive bacteria but represents a separate branch of this group. On the basis of morphological and physiological features and phylogenetic data, this isolate should be assigned to a new genus, for which the name Carboxydobrachium is proposed. The type species is Carboxydobrachium pacificum; the type strain is JMT (= DSM 12653T).

Bacteria, Anaerobic↗