Biomedical subjects

P Ochoa

Publications and source records attributed to P Ochoa.

18 recordsLinked to original sources

PubMed2001

Effect of parasite burden on the detection of Fasciola hepatica antigens in sera and feces of experimentally infected sheep.

The effect of Fasciola hepatica parasite burden on the detection of excretory/secretory (E/S) antigens in sera and feces of experimentally infected sheep was evaluated using a double antibody-based capture enzyme-linked immunosorbent assay (ELISA). Four groups of five sheep each were used. The first three groups were infected with 50, 100 and 200 metacercariae of F. hepatica, and the fourth group remained as non-infected control. On the day of infection and weekly thereafter, serum and fecal samples were taken. ELISA detected F. hepatica E/S antigen levels in serum from the first week post-infection (wpi) and in fecal supernatant from the fourth wpi, which were significantly (p<0.05) higher than controls. F. hepatica eggs were not detected until after the eighth wpi. The correlation between absorbance of E/S antigens in serum with the fluke burden was 0.77 (p<0.0001) and in feces 0.76 (p<0.0001) at 12th wpi. The sensitivity of the assay to detect E/S antigens in serum was 86.6% and in feces 93.3%. It is concluded that the ELISA technique used in this study offers a diagnostic alternative for detecting early infections of F. hepatica in sheep.

Animals↗

PubMed2001

Identification of a proximal promoter region critical for the expression of the beta-F1-ATPase gene during Drosophila melanogaster development.

We have studied the spatio-temporal pattern of expression of the gene encoding the H(+) adenosine triphosphate (ATP) synthase beta subunit (beta-F1-ATPase) during Drosophila melanogaster development. The beta-F1-ATPase mRNA is stored in the egg; as development proceeds it is distributed in most embryonic cellular territories, including the mesoderm, and in late embryos it is highly abundant in the ventral cord and midgut. Using a combination of transfection assays in Schneider cells and P-element transformation in flies, we have identified a proximal 5' upstream region of 258 bp essential for the transcriptional activity of the gene during D. melanogaster embryogenesis that is virtually inactive in adult tissues. Electrophoretic mobility shift assays using specific DNA fragments from the 258-bp region detect in embryonic nuclear extracts a complex set of DNA binding proteins that are largely absent in adults. The transcription factor CF2-II has been identified as a potential candidate in the regulation of the beta-F1-ATPase gene.

Journal Article↗

PubMed2001

Accuracy and repeatability of the Yale physical activity survey in assessing physical activity of older adults.

The purpose of this study was to extend the initial evaluation of the Yale Physical Activity Survey to assess physical activity in older adults. The survey yields three indicators of physical activity reflecting activities performed during a typical week of the previous month (Total Time, Total Energy Expenditure) and the past month (Total Activity Summary Index). Questionnaire validity was studied in 56 men and women, ages 56 to 86 years, by comparing the average of 3- or 7 day 24-hr. physical activity records (n=56), predicted maximal oxygen consumption (VO2 max) (n = 23) and the sum of three skinfold measurements. Two-week repeatability was estimated by calculating an intraclass coefficient using an analysis of variance with repeated measures. Spearman rhos were used to study questionnaire validity. Analysis showed the survey was easily administered and scored and exhibited moderate-to-good repeatability. For the first administration the Total Energy Expenditure Index was significantly associated with the physical activity diary (r = .27). On the second administration, correlations were significant for the physical activity diary with the Total Energy Expenditure Index (r = .30), the Total Activity Summary Index (r = .36), and the Total Time Index (r = .27), and for VO2 max and the Total Time Index (r = .49) and Total Activity Summary Index (r = .64). Relative to the criterion measures used in this study, some validity was evident for the second administration in this relatively active and healthy sample of older adults.

Aged↗

PubMed1998

Comparison of three ELISA tests for seroepidemiology of bovine fascioliosis.

The aim of the present study was to compare the sensitivity, specificity and usefulness of the DIG-ELISA, DOT-ELISA and Indirect ELISA tests for determining the seroprevalence of fasciolosis in cattle under tropical conditions in Mexico. To standardize the tests, positive and negative sera to F. hepatica from 88 Holstein Freisian adult cows located in an enzootic area of fascioliosis and 88 crossbred adult cattle from a fluke-free area were used. For the epidemiological study, 85 crossbred cattle between 1 to 7 years of age were used. Animals were bled every two months, from March 1995 to September 1996 and the sera obtained were stored at -70 degrees C, until used. Indirect ELISA showed a sensitivity of 96.5% and a specificity of 98.8%, DIG-ELISA 97.5% and 80.0% and DOT-ELISA 93.1% and 95.4%, respectively. During 1995, Indirect ELISA yielded the highest levels of IgG anti-F. hepatica antibodies. However, in 1996, after animal treatment with triclabendazole, DIG-ELISA tended to show higher percentages of antibody-positive animals, but it was not significantly different (p>0.05) from the other tests. Comparisons made in parallel to the faecal sedimentation test demonstrated that all serological tests detected higher percentages of positive animals. Only one serum out of ten (10%) of Paramphistomum spp. cross-reacted with the DOT-ELISA test, but no cross-reaction was observed with sera from animals with other parasites. All ELISA tests were highly sensitive and specific; they may be recommended for use in seroepidemiological surveys for F. hepatica.

Animals↗

PubMed1998

Mitochondrial gene expression and respiratory enzyme activities in cardiac diseases.

Respiratory enzyme activities and steady-state level of two mitochondrial-encoded transcripts were quantified in heart muscle biopsies from patients suffering various types of cardiomyopathies unrelated to mitochondrial primary disorders. We have found that although the mitochondrial DNA copy number and the concentration of COI and ND4 transcripts remain fairly constant, there is an important increase (up to 6-fold) in respiratory enzyme activities affecting to several oxidative phosphorylation complexes. Idiopathic dilated cardiomyopathy shows the greatest increase, followed by ischemic heart and ventricular hypertrophy due to aortic stenosis. The results suggest an energetic compensatory mechanism in the heart muscle, in the absence of mitochondrial proliferation or activation of mitochondrial gene expression.

DNA, Mitochondrial↗

PubMed1996

[The assessment of functional status in hospitalized elderly patients: the Plutchik scale].

BACKGROUND: To study the usefulness of the Plutchik Scale to measure functional capacity in daily activities of hospitalized elderly patients. PATIENTS AND METHODS: A sample of 300 patients stratified by age and sex (111 male and 189 female), mean age 81 years, hospitalized in the Geriatric Unit, was selected from all the patients admitted to our Unit along the year 1994 (n = 974, mean length of stay in acute beds 15 days, in convalescent beds 57 days, total 19 days). Scores of patients in the Plutchik Scale, Katz Activities of Daily Living and Barthel ADL Index were obtained. Ninety seven of the subjects were rated by two independent observers. RESULTS: The kappa statistic of interrater reliability in Plutchik Scale scoring was high (0.807). There was a good correlation between the three instruments at cut-points for autonomy/dependence: 0.824 for cut-points 4/5 in Plutchik Scale and 2/3 in Katz Activities of Daily Living; 0.846 for cutpoints 4/5 in Plutchik Scale and 55/60 in Barthel ADL Index (p < 0.01). The coefficient alpha (Cronbach) in Plutchik Scale was 0.876 and the standardized alpha 0.868, which reflect that the Plutchik Scale is internally consistent. By factor analysis one factor was obtained explaining 58% of the variance. The factor showed the highest correlation with "washing/dressing" (0.861) and lowest with "vision" (0.349). CONCLUSIONS: The Plutchik Scale is a good instrument for measuring functional capacity in hospitalized elderly patients.

Activities of Daily Living↗

PubMed1996

Mitochondrial differentiation during the early development of the brine shrimp Artemia franciscana.

During the early development of Artemia there is an increase in mitochondrial enzyme activities of about one order of magnitude, whereas the activities of two cytoplasmic enzymes tested as controls remain unaltered. The mitochondrial enzyme activation correlates with (i) large changes in mitochondrial morphology, (ii) a 5-fold increase in the amount of the H+-ATP synthase beta-subunit and (iii) a dramatic increase in the steady-state level of mitochondrial mRNAs, whereas mitochondrial rRNA concentrations remain mostly unchanged. In contrast, the level of mitochondrial DNA does not change significantly during the first 20 h after resumption of development. After hatching, the mitochondrial DNA content increases twice in parallel with one round of cellular division, thus indicating that mitochondrial and nuclear replication are coupled in Artemia postgastrular development. The data presented strongly suggest that mitochondrial maturation in the absence of significant mitochondrial proliferation is responsible for the dramatic increase in mitochondrial function that takes place after resumption of development in Artemia.

Adenosine Triphosphatases↗

PubMed1995

Role of glycosyl-phosphatidylinositol hydrolysis as a mitogenic signal for epidermal growth factor.

We have investigated the role of the hydrolysis of glycosyl-phosphatidylinositol (GPI) as one of the signalling pathways elicited after interaction of epidermal growth factor (EGF) with its specific plasma membrane receptor (EGFR). Endogenous GPI was characterized in both NIH 3T3 mouse fibroblast cells and in EGFR-transfected NIH 3T3 cells (designated EGFR T17). GPI molecules isolated from both cell lines were identical and they incorporated radioactivity from both sugar and fatty acid substrates. Incubation of EGFR T17 cells with EGF, produced a rapid and transient hydrolysis of GPI. Maximum hydrolysis occurred after a 1-min incubation with 50 nM EGF. No such effects of EGF were observed in the parental cell line. Both inositol phosphoglycan (IPG)- and EGF-induced cell proliferation was inhibited in the presence of an IPG-antibody to different extents. The relationship between GPI hydrolysis and the activity of the EGFR was studied using the tyrosine kinase inhibitors tyrphostin (RG50864) and genistein. These agents were able to significantly inhibit EGF-mediated cell proliferation, EGF-dependent hydrolysis of GPI and EGF-regulated autophosphorylation of the EGFR. It is concluded that GPI hydrolysis is one of the earliest intracellular events generated in response to EGF.

3T3 Cells↗

PubMed1994

Evidence of hypertrophic osteoarthropathy in human skeletal remains from pre-Hispanic Mesoamerica.

Hypertrophic osteoarthropathy is one of the earliest recognized disease entities in the history of medicine. It has a peculiar periosteal proliferation distinctive from other bone diseases. In its advanced stage, it leaves an indelible mark on the skeleton. It has been recently shown that digital clubbing is accompanied by a bone remodeling process of the underlying phalanges. Thus, theoretically, this entity can be recognized in ancient human skeletal remains. We studied part of the collection of skeletal remains from pre-Hispanic Mesoamerica preserved at the National Museum of Anthropology of Mexico City. We examined 1000 specimens and found 2 skeletons with widespread, bilateral, symmetric periosteal proliferation of the tubular bones in addition to the bone remodeling changes of the distal phalanges. One of the specimens was from the Formative period (2000 B.C. to 100 A.D.). We conclude that hypertrophic osteoarthropathy can be recognized in ancient human skeletal remains and that this disease was present in Mesoamerica near the time of the original description of clubbing by Hippocrates about 2500 years ago.

Central America↗

PubMed1992

Role of the glycosylphosphatidylinositol/inositol phosphoglycan system in human fibroblast proliferation.

The involvement of the glycosylphosphatidylinositol/inositol phosphoglycan (gly-PtdIns/IPG) system in the stimulation of macromolecular syntheses in human fibroblasts has been investigated. The study demonstrates that an insulin sensitive gly-PtdIns/IPG system is present in human fibroblasts, that IPG can significantly stimulate DNA, RNA, and protein synthesis, and that the action of insulin on DNA synthesis as well as that of IPG can be significantly reduced by a specific anti-IPG antibody. These results strongly support the hypothesis that the gly-PtdIns/IPG system is involved in the signal transduction pathway leading to the stimulation of cell proliferation.

Cell Division↗

PubMed1991

The role of cysteine-150 in the structure and activity of rat liver S-adenosyl-L-methionine synthetase.

The present paper reports the tryptic digestion of N-ethylmaleimide-treated S-adenosyl-L-methionine synthetase (high- and low-Mr forms) and the isolation of the modified peptides by h.p.l.c. There is only one site modified after 5 min incubation, and the modification at this site correlates with the main activity decrease. The amino acid composition of this peptide was determined, and its localization in the sequence shows the modified residue as cysteine-150, which is located close to the putative ATP-binding site. Modification of the enzyme for 20 min led to the appearance of a second labelled peptide, which seems to be responsible for about a further 10% of the activity loss. The modification by N-ethylmaleimide of the enzyme was partially prevented in the presence of adenosine 5'-[beta gamma-imido]triphosphate and methionine, further supporting the hypothesis that the modified residues lie within the active site. Urea treatment of the enzyme, followed by modification with N-ethylmaleimide, produces the modification of 7 of the 10 cysteine residues present in the sequence. The results obtained were the same for either of the isoforms.

Amino Acids↗

PubMed1991

Inhibition of glutathione synthesis in the liver leads to S-adenosyl-L-methionine synthetase reduction.

The hepatic levels of glutathione in rats treated with buthionine sulfoximine (4 mmol/kg), an inhibitor of glutathione synthesis, were 72.5% +/- 4.9% of those determined in control animals. This decrease in glutathione concentration was prevented by the administration of glutathione monoethyl ester (7.5 mmol/kg). S-Adenosyl-L-methionine-synthetase activity in the liver of rats treated with buthionine sulfoximine was 39.4% +/- 6.5% of that determined in control animals. Again, glutathione monoethyl ester prevented the effect of buthionine sulfoximine on S-adenosyl-L-methionine-synthetase activity. There was a close correlation (r = 0.936) between the hepatic levels of glutathione and S-adenosyl-L-methionine-synthetase activity. The hepatic concentration of S-adenosyl-L-methionine in buthionine sulfoximine-treated animals was 59.7% +/- 3.7% of that measured in control rats. Contrasting with the protective effects mentioned above, glutathione monoester had no preventive action on buthionine sulfoximine-induced S-adenosyl-L-methionine depletion. Electron microscopic examination of liver samples of rats after buthionine sulfoximine administration showed evidence of liver degeneration, which was attenuated by glutathione monoethyl ester treatment. Glutathione (7.5 mmol/kg) treatment was less effective than glutathione monoethyl ester in attenuating buthionine sulfoximine effects on hepatic S-adenosyl-L-methionine metabolism and morphology. The reduction of S-adenosyl-L-methionine-synthetase activity observed after treatment with buthionine sulfoximine and its prevention by glutathione monoethyl ester, as well as the correlation between the activity of this enzyme and glutathione levels, indicate that glutathione plays an important role in maintaining S-adenosyl-L-methionine-synthetase activity in the liver.

Acetaminophen↗

PubMed1975

Regional and cellular localization of glycosyltransferases in rat small intestine. Changes in enzymes with differentiation of intestinal epithelial cells.

Optimal assay conditions were determined for four glycosyltransferases in rat small intestinal mucosal homogenates and the regional distribution and cellular localization of these enzymes was studied. For each glycosyltransferase, similar levels of activity were found in duodenal, proximal jejunal and distal ileal segments; activities of the galactosyltransferases were lower in the distal jejunal-proximal ileal segment. Planar section studies indicated that the undifferentiated crypt cells had significantly higher levels of sialyltransferase activities in the jejunum and ileum than the mature villus cells. A similar crypt to villus gradient was found for a galactosyltransferase in the ileum. These data suggest that glycoprotein synthesis may be active in the undifferentiated crypt cells and that certain glycosyltransferases may serve as marker enzymes for cellular differentiation in the intestine.

Animals↗

PubMed1974