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Biomedical subjects

A M García

Publications and source records attributed to A M García.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Genetic and molecular study of cystinuria in the Valencian community].

BACKGROUND: The aim of this study has been to know the prevalence of the four most common mutations reported in SLC3A1 gene involved in human cystinuria, and to estimate the association with different phenotypic manifestations of this disease in population of the Valencian Community, Spain. PATIENTS AND METHODS: We have carried out a cross-sectional study with a control group in 16 families with one or more members diagnosed as cystinuric patients. 149 subjects (38 cystinuric patients, 39 relatives and 72 controls) were studied. Genetic analyses were carried out using PCR (polymerase chain reaction), RFLPs (restriction fragment length polymorphisms) and sequencing of PCR products. Parametric and non parametric tests were applied in the statistical analyses. RESULTS: None of the four mutations studied were found in the control group. M467T mutation was the most prevalent in cystinuric patients as well as in relatives, showing and allelic frequency of 0.06 and 0.03 respectively. Regarding to the association analysis between genotype and phenotype, we found that, in cystinuric subjects, urinary excretion of some dibasic amino acid was higher in those who carried M467T mutation (p < 0.05). The formation of cystine crystals was also higher in cystinuric patients who carried this mutation (p < 0.05). CONCLUSIONS: Prevalences of recurrent mutations reported up to now in SLC3A1 gene are very low in cystinuric subjects of the Valencian Community, Spain. Only mutation M467T has been found, without differences between cystinuric and their relatives, although in the first ones was associated with a more accurate phenotype manifestation of the disease.

Adolescent↗
PubMed1999

Identification of peptides presented by HLA class I molecules on cervical cancer cells with HPV-18 infection.

In this work we eluted peptides from purified class I MHC molecules, isolated from a novel human cervical carcinoma cell line (INBL), generated in our laboratory and positive for HPV-18 infection. A fraction of these peptides was capable of stimulating T lymphocytes obtained from a donor matched for HLA-Cw4 and who was also HPV-18+. Direct N-terminal Edman degradation of these peptides, revealed the sequence (XQFPIFLQF) that matched 85% with the sequence NVFPIFLQM localized in between the 54 and 62 residues of the HPV-18 L1 protein. After stimulation with the synthetic peptide NVFPIFLQM, T lymphocytes from the donor were capable to lyse INBL cells. Our results provide evidence of the existence of naturally occurring viral epitopes presented on cervical cancer cells by the HLA-Cw4 allele, that could be useful for immunotherapy on this type of patient.

Amino Acid Sequence↗
PubMed1999

Parental agricultural work and selected congenital malformations.

The authors conducted a case-control study in Comunidad Valenciana, Spain, to assess the relation between occupational exposure to pesticides, mainly as a result of agricultural work, and the prevalence of congenital malformations. A total of 261 cases and 261 controls were selected from those infants born in eight public hospitals during 1993-1994. The cases were those who were diagnosed with selected defects (nervous system, cardiovascular, oral clefts, hypospadias/epispadias, musculoskeletal, and unspecified anomalies) during their first year of life. Information on occupational exposures and potential confounding variables was collected from the parents. For the mothers who were involved in agricultural activities during the month before conception and the first trimester of pregnancy, the adjusted odds ratio was 3.16 (95% confidence interval 1.11-9.01) primarily due to an increased risk for nervous system defects, oral clefts, and multiple anomalies. Paternal agricultural work did not increase the risk, although fathers who reported ever handling pesticides had an adjusted odds ratio of 1.49 (95% confidence interval 0.94-2.35) mainly related to an increased risk for nervous system and musculoskeletal defects. Although the power of this study regarding some associations is limited, the results justify further attention to maternal agricultural work and paternal pesticide exposure.

Adult↗
PubMed1999

Reference values of urinary excretion of cystine and dibasic aminoacids: classification of patients with cystinuria in the Valencian Community, Spain.

OBJECTIVE: Cystinuria is an autosomal-recessive disorder of the kidneys and small intestine affecting a luminal transport mechanism shared by cystine, ornithine, arginine, and lysine. Three different types of cystinuria can be distinguished according to the excretion of these amino acids in urine samples. We propose cutoff values from our population as references and we present a classification of cystinuric patients using quantitative amino acid chromatography in first morning urine samples. DESIGN AND METHODS: A random sample of forty healthy subjects belonging to general population of the Valencian Community were selected as control subjects. Cystine, lysine, arginine, and ornithine were quantified by reverse-phase HPLC. Seventy-two subjects, diagnosed previously as cystinuric by the cyanide-nitroprusside test were classified. Probands excreting more than 113.12 micromol cystine per mmol of creatinine (i.e., 1,000 micromol cystine per gram of creatinine) were classified as homozygotes. Parents of homozygotes in whom excretion of amino acids were normal were classified as heterozygotes type I. Those probands showing the excretion of at least one amino acid and the sum of urinary cystine plus the basic amino acids higher than the corresponding references ranges in our population were classified as heterozygotes type II or type III (heterozygotes non-type 1). RESULTS: We identified 24 homozygotes, 39 non-type I heterozygotes and 3 type I heterozygotes. The remaining 6 probands could not be classified. Means for cystine, lysine, arginine ornithine and their sum in homozygotes and heterozygotes non-type I were significantly (p < 0.001) in excess of the respective reference ranges. Moreover, means values in homozygotes were statistically different (p < 0.001) from heterozygotes non-type I. CONCLUSION: Urinary excretion of cystine per mmol creatinine allow us to distinguish heterozygotes from homozygotes. However, the best discriminator to distinguish non-type I heterozygotes from normal population might be the excretion of lysine per mmol creatinine. Additional studies including characterization of appropriate haplotypes should be carried out for a more precise identification of types of cystinuria.

Adolescent↗
PubMed1998

Flow cytometric DNA analysis and p53 protein expression show a good correlation with histologic findings in patients with Barrett's esophagus.

BACKGROUND: There is a considerable degree of subjectivity and, therefore, substantial interobserver and intraobserver disagreement in the diagnosis and grading of dysplastic lesions in Barrett's esophagus (BE). The aim of this study was to evaluate the usefulness of DNA flow cytometry and immunohistochemical staining for p53 protein as objective methods to complement the conventional histologic diagnosis of dysplasia in patients with this disease. The most common problems and the possible advantages of using these procedures are analyzed briefly in this article. METHODS: Formalin fixed, paraffin embedded tissue from 55 patients diagnosed with BE were processed for flow cytometric measurements (ploidy and proliferation index) and p53 immunostaining. RESULTS: Both the cytometric data and the positivity of staining for p53 revealed a statistically significant increase throughout the following sequence: no dysplasia --> indefinite for dysplasia --> low grade dysplasia --> high grade dysplasia --> adenocarcinoma. There was also a highly significant correlation between the results of the cytometric study and the positivity of staining for p53. CONCLUSIONS: In the future, the use of this procedure could play an important role in the evaluation of patients with BE. Considering that staining for p53 is technically simple, economical, and quick, and the materials required are available to most pathology laboratories, this method appears to be a firm candidate for application as a biomarker in BE. The authors have shown that it is possible to obtain adequate results for cytometric analysis with small formalin fixed, paraffin embedded biopsies if a strict protocol for the acceptance of tissue samples and/or histograms is observed.

Adenocarcinoma↗
PubMed1998

Bone regeneration after radicular cyst removal with and without guided bone regeneration.

In order to determine the degree of bone regeneration after removal of radicular cysts using guided bone regeneration (GBR), a prospective, controlled and randomized clinical study was performed. Thirty patients with radicular cysts were divided into three groups. One group, the control group (n=10 patients), was treated by enucleation and primary closure. The other two groups were treated by enucleation and primary closure but GBR was used in addition, using a resorbable membrane (n=10) and a nonresorbable membrane (n=10). The membranes were fixed with nonresorbable Memfix System screws. The residual volume and the density of the newly formed tissue was measured by computer-assisted tomography and computer-assisted digital image analysis before enucleation and three and six months postoperatively. No statistical significance was found in density and residual volume between the three treatment groups after six months. These results suggest that GBR using membranes does not contribute to increased bone regeneration.

Adult↗
PubMed1998

Maternal occupation in the leather industry and selected congenital malformations.

OBJECTIVES: Data from a hospital based case-control study were analysed to assess the relation between maternal occupation in the leather industry and several groups of congenital defects (nervous system, cardiac defects of closure, oral cleft, epispadia or hypospadia, and multiple anomalies). METHODS: Cases and controls were selected from eight public hospitals in Comunidad Valenciana, Spain, in 1993 and 1994. Cases were located from the hospital discharge records, including children born and diagnosed in some of the selected hospitals during their first year of life. Controls were selected from births without congenital defects in the same hospitals and dates of the cases (ratio 1:1). Both parents of selected children were interviewed (mainly by phone) and information about potential confounding variables and occupational history during the three years before the birth was collected in structured questionnaires. RESULTS: A total of 261 cases and the same number of controls were included in the study. Adjusted odds ratios (ORs) were estimated for maternal occupation in the leather industry in the period between three months before the conception and the birth of the child (n = 22), and each selected group of congenital malformations: nervous system defects (OR 1.02, 95% confidence interval (95% CI) 0.12 to 8.51), cardiac defects of closure (OR 1.78, 95% CI 0.44 to 7.17), oral clefts (OR 6.18, 95% CI 1.48 to 25.69), for epispadia or hypospadia (OR 4.05, 95% CI 0.77 to 21.44), and multiple anomalies (OR 3.14, 95% CI 0.82 to 12.00). CONCLUSION: These data are compatible with an increased risk for oral clefts in the offspring of women working in the leather industry. Some other categories of defect could have an increased risk as well, although for these our data cannot exclude random error as an explanation. Given these results and previous findings in similar studies, some precautionary recommendations regarding maternal exposure in leather industries, probably in relation to solvents, would be justified.

Case-Control Studies↗
PubMed1998

Paternal exposure to pesticides and congenital malformations.

OBJECTIVES: A case-referent study with 261 matched pairs was carried out in 8 hospitals of Comunidad Valenciana, Spain, to assess the relation between occupational exposure to pesticides and selected congenital malformations. In this paper, the results concerning paternal exposure are presented. METHODS: The parents of the case patients and the referents were interviewed to collect information about exposure to pesticides and potential confounding variables. Detailed information on direct involvement in the handling of pesticides was collected for the interviewees involved in agricultural activities during a previously defined period in relation to conception and pregnancy. Exposure data were reviewed by 2 experts who assigned ordinal scores for the probability and intensity of exposure to pesticide classes and active ingredients. RESULTS: The dichotomous analysis of exposure (absent, present) yielded some increased risks, although not statistically significant, for aliphatic hydrocarbons [adjusted odds ratio (adjusted OR) 2.05, 95% confidence interval (95% CI) 0.62-6.80], inorganic compounds (adjusted OR 2.02, 95% CI 0.53-7.72), and glufosinate (adjusted OR 2.45, 95% CI 0.78-7.70), and a significant association for pyridil derivatives (adjusted OR 2.77, 95% CI 1.19-6.44). The analysis based on the experts' scores (2 levels of exposure) showed some consistent associations for these compounds. CONCLUSIONS: This research indicates a possible risk of congenital malformations for paternal exposure to some pesticides, notably, pyridils, aliphatic hydrocarbons, inorganic compounds, and glufosinate. It did not find an increased risk for paternal exposure to pesticides in the classes of organophosphates, carbamates, organochlorines, chloroalkylthio fungicides and organosulfurs. These findings warrant further investigation.

Agriculture↗
PubMed1998

Occupational exposure to pesticides and congenital malformations: a review of mechanisms, methods, and results.

Pesticides are chemicals that are widely used all over the world. Human beings can be exposed through environmental contamination and/or occupational use of pesticides. Although there is substantial information on the acute toxicity of many of these chemicals, available knowledge on delayed effects is much more limited. This paper reviews epidemiological studies on occupational exposure to pesticides, mainly in agricultural workers, and risk of congenital malformations. The discussion includes postulated mechanisms for birth defects from paternal or maternal exposure, a detailed review of method of the studies carried out so far on the relationship between occupational exposure to pesticides and congenital malformations, and a summary of main results obtained. From available information, it seems reasonable to conclude that, to date, there is inadequate evidence for either establishing a relationship between pesticides exposure in human beings and birth defects or for rejecting it. Avoiding the main limitations of previous studies, some of the key elements for future research are presented.

Abnormalities, Drug-Induced↗
PubMed1997

Stereoselective inhibition of rat brain cyclooxygenase by dexketoprofen.

Although it has been assumed that the effects of nonsteroidal antiinflammatory drugs (NSAIDs) are mainly the result of their action on local synthesis of prostaglandins, there is growing evidence to suggest that they may also exert a central analgesic action. Some authors have suggested that inhibition of prostaglandin synthesis in the brain could contribute to the analgesic action. The effect of dexketoprofen trometamol (tromethamine salt of the enantiomer (+)-S-ketoprofen) on prostaglandin synthesis was investigated in rat brain fragments and in cyclooxygenase preparations from rat brain microsomes. Effects of the (-)-R-enantiomer and the racemic mixture were also evaluated. Significant levels of prostaglandin F2 alpha (PGF2 alpha) were synthesized in rat brain fragments after 10 min of incubation at 37 degrees C. Dexketoprofen was found to be a potent inhibitor of this PGF2 alpha production in rat brain (IC50 = 6.2 nM), and it completely suppressed PGF2 alpha production at 1 microM concentration. In addition, inhibition of PGF2 alpha synthesis by dexketoprofen was highly stereoselective since the enantiomer (-)-R-ketoprofen was significantly less potent (IC50 = 294 nM); with this enantiomer, even at high concentrations such as 1 microM, less than 60% inhibition was achieved. These results correlated with those obtained in the study of racemic ketoprofen and its enantiomers on cyclooxygenase activity of rat brain microsomes, where dexketoprofen also inhibited enzymatic activity stereoselectively. IC50 values obtained for dexketoprofen, (-)-R-ketoprofen, and rac-ketoprofen were 3.5 microM, 45.3 microM, and 5.8 microM, respectively. The above results could be related to the potent analgesic effect of dexketoprofen observed in vivo, which was also stereoselective. Taken together, these findings suggest that prostaglandin synthesis inhibition in rat brain by dexketoprofen could be associated, at least in part, with the analgesic effect of this NSAID.

Animals↗
PubMed1996

Molecular cloning, nucleotide sequencing, and characterization of a 27-kDa antigenic protein from Paracoccidioides brasiliensis.

A gene encoding a 27-kDa antigenic protein from Paracoccidioides brasiliensis was cloned, sequenced, and characterized. A cDNA library of the mycelial phase was produced and packed in Uni-Zap-XR vector, lambda Zap II synthesis kit (Stratagene, La Jolla, Ca). The screening of the library was carried out using a pool of sera from paracoccidioidomycosis patients that had proven reactive in serological testing. Among 44,000 immuno-screened clones from the library, 2 were positive (clones 2 and 3). The former was not characterized further. The latter has a 1-kb DNA insert with an open reading frame encoding a protein of 259 amino acids with a predicted molecular mass of 28.6 kDa (27 kDa by SDS-PAGE). This protein corresponds to a 25-kDa protein in antigenic preparations of P. brasiliensis as determined by Western blot analysis. Comparison of the transcribed sequence with different gene banks failed to reveal a high degree of homology with other proteins. The cloned DNA fragment was easily expressed in Escherichia coli without the need of induction by isopropyl-beta-D-thiogalactopyranoside. These findings suggest that the gene encodes a P. brasiliensis-specific protein.

Amino Acid Sequence↗
PubMed1996

Effect of manoalide on human 5-lipoxygenase activity.

The marine natural product manoalide (MLD) has been described to inactivate phospholipase A2 (PLA2) from several sources as well as to inhibit synthesis of eicosanoids in human polymorphonuclear leukocytes (HPMNL). MLD also reduces chemically-induced inflammation in vivo. In this investigation we have examined the effect of MLD on A23187-induced generation of leukotriene B4 (LTB4) and thromboxane B2 (TXB2) in HPMNL as well as 5-lipoxygenase (5-LO) activity from HPMNL sonicated preparations. In the intact cell system, MLD inhibited with similar potency biosynthesis of LTB4 and TXB2 (IC50 1.7 and 1.4 microM, respectively). In order to discern if inhibition of 5-LO is involved in the effect of MLD, we examined the action of this compound on 5-LO activity from 10,000 x g and 100,000 x g supernatants of sonicated HPMNL homogenates. The enzymatic activity was not affected at concentrations of MLD up to 50 microM. These data indicate that MLD is not a direct inhibitor of 5-LO activity from HPMNL and support the hypothesis that its anti-inflammatory action could be related with a reduction of eicosanoid biosynthesis via inhibition of PLA2.

Arachidonate 5-Lipoxygenase↗
PubMed1996

Erythrocyte alkaline phosphatase in patients with myotonic muscle disorders.

The allosteric behaviour of the p-nitrophenyl-phosphatase (E.C.3.1.3.1.) from membrane erythrocytes was investigated in the following multisystemic diseases: myotonic dystrophy, limb-girdle muscular dystrophy, Charcot-Marie-Tooth and juvenile spinal muscular atrophy; in myotonia congenita, which is not a multisystemic disease, and in healthy controls. The Hill coefficient in F inhibition in controls was different from that in multisystemic diseases patients but not from that in myotonia congenita patients. Changes in the cooperative type kinetics would suggest that the interaction membrane-enzyme in controls and in patients with neuromuscular disorders is only different for multisystemic diseases.

Alkaline Phosphatase↗
PubMed1996

[Description of a population with four associated cardiovascular risk factors and the relationship of these with basal insulinemia].

OBJECTIVES: To describe patients who have four cardiovascular risk factors linked: hypertension, carbohydrate metabolic disturbances, overweight and dyslipaemia. To determine basal insulin levels. DESIGN: A descriptive crossover study. SETTING: Tórtola Health Centre, East Valladolid. PARTICIPANTS: Of the 6,950 patients with medical records and over 45, 76 cases met the 4 factors. An appointment was made by phone to determine basal insulinaemia. RESULTS: Average age was 64.38; 75% were women. 92.1% were non-smokers and 26.3% moderate consumers of alcohol. 43.4% were intolerant; the rest, diabetics. 52.6% received no drugs treatment. The commonest monotherapy was sulfonylureas and insulin. Mean BMI was 30.20, and obesity, 63.2%. The commonest hypertension drugs were ACEIs and diuretics, as monotherapy: both together was the commonest association. All the patients were hypercholesterolaemic. 25% were on antilipaemiant treatment, the commonest fibrates. All the patients were on a prescribed diet. 34.2% had hyperuricaemia. Mean insulinaemia was 12.63. There were 5 cases with high values. CONCLUSIONS: There is 1.09% prevalence of the four cardiovascular risk factors linked. High levels of basal insulin were only found in 5 patients. Biguanidines were not used in treatment of DM II. There were more obese patients vs those with overweight. Failure of diet to control dyslipaemias. Insulin should not be systematically determined in primary care because it is of little use.

Aged↗
PubMed1995

Sb(III) and Sb(V) separation and analytical speciation by a continuous tandem on-line separation device in connection with inductively coupled plasma atomic emission spectrometry.

A sensitive, precise and automated non-chromatographic method for Sb(III) and Sb(V) analytical speciation based on a continuous tandem on-line separation device in connection with inductively coupled plasma-atomic emission (ICP-AES) detection is proposed. Two on-line successive separation steps are included into this method: a continuous liquid-liquid extraction of Sb(III) with ammonium pyrrolidine dithiocarbamate (APDC) into methylisobuthylketone (MIBK), followed by direct stibine generation from the organic phase. Both separation steps are carried out in a continuous mode and on-line with the ICP-AES detector. Optimization of experimental conditions for the tandem separation and ICP-AES detection are investigated in detail. Detection limits for Sb(III) were 3 ng.mL(-1) and for Sb(V) 8 ng.mL(-1). Precisions observed are in the range +/- 5%. The proposed methodology has been applied to Sb(III) and Sb(V) speciation in sea-water samples.

Journal Article↗
PubMed1994

Effects of physicochemical factors on the growth of mandibular condyles in vitro.

Cartilage growth and remodeling are known to be influenced by the biochemical and mechanical environment of the tissue. Previous investigators have shown that chemical factors that are relevant to mechanical loading, such as osmotic pressure and pH, induce changes in cartilage metabolism in vitro. Using a neonatal rat mandibular condyle culture system, the objectives of the work reported here were to determine (1) how the growth is influenced by osmotically applied mechanical loads; and (2) whether changes in intratissue osmotic pressure or pH cause metabolic changes in the cartilage which are then reflected by altered growth behavior. High molecular weight (MW) uncharged macromolecules polyvinylpyrrolidone (PVP) and Ficoll (presumed unable to penetrate the tissue matrix) were used to examine the effect of osmotic loading on tissue growth; concentrations corresponding to osmotic pressures of up to 100 kPa resulted in a dose-dependent depression in growth and matrix accumulation. Raffinose (which can penetrate the matrix but not the cells) had no significant effect on growth for osmotic pressures of up to 87 kPa, suggesting that compression-induced changes in intratissue osmotic pressure are unlikely to provide a signal by which cells sense and respond to mechanical compression. By contrast, changes in medium pH resulted in dose-dependent changes in growth behavior. Specifically, slight alkalinity (acidity) greatly enhanced (diminished) growth and matrix accumulation; the sensitivity to pH suggests that intratissue pH could provide a mechanism for cells to sense local glycosaminoglycan concentration and mechanical compression.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Protein synthesis in the developing rat liver: participation of initiation factors eIF-2 and eIF-2B.

We studied the decline in protein synthesis in the developing liver in suckling rats (4 to 10 days) and adult rats (2 mo). The rate of protein synthesis was measured with a cell-free system and compared with the activity of two initiation factors, eukaryotic initiation factor-2 and eukaryotic initiation factor-2B, and with casein kinase II, which phosphorylates both factors in vitro. The specific activity of the three parameters decreased in adult rats compared with suckling rats and in parallel to the rate of protein synthesis. Quantification of eukaryotic initiation factor-2 in the ribosomal salt wash and in the postmicrosomal supernatant showed that both the specific activity and the levels of eukaryotic initiation factor-2, are much higher in the ribosomal salt wash fractions than in postmicrosomal supernatants, but no differences were found between the two age groups. The eukaryotic initiation factor-2/ribosome ratio was higher in adult rats than in suckling rats, and this parameter seems to be inversely proportional to the rate of protein synthesis. The phosphorylation state of eukaryotic initiation factor-2 alpha, as determined by isoelectric focusing followed by protein immunoblotting, revealed very low and equal levels of phosphorylation in the two animal groups. The lack of changes in eukaryotic initiation factor-2 levels and phosphorylation status suggests that a decrease in the activity or levels of eukaryotic initiation factor-2B could be responsible for the decrease in eukaryotic initiation factor-2 activity and account for, at least in part, the differences observed in the rates of protein synthesis.

Aging↗