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Biomedical subjects

C Rodriguez

Publications and source records attributed to C Rodriguez.

At least 217 records · Page 12Linked to original sources
PubMed1986

Bioenergetic and cardiovascular responses to exercise in residents at 2.850 m, with asymptomatic Chagas' disease.

Cardiovascular and energetic responses at rest, during 30 min of exercise (mechanical output: 125 watts) and for a subsequent recovery period of 5 min were compared in two groups, each comprising 21 residents at an altitude of 2.850 m. One group was in the asymptomatic phase of Chagas' disease with positive serological tests for T. cruzi, whereas the other was without Chagas' disease (negative serological tests). The two groups were similar as regards age, weight-for-height, blood parameters, nutritional status and heart and lung functions, including heart rate and frontal plane QRS axis determinations. At rest, they differed in that maximal and minimal arterial blood pressures were slightly but significantly lower in the group with Chagas' positive serological tests than in the controls. During exercise and recovery, the only differences between them and the controls were that their minimal diastolic arterial blood pressure was significantly lower. In absolute values, the rises in arterial pressure due to exercise were exactly the same in the two groups. Maximal O2 uptake was identical in both groups, as was exercise steady state VO2. These findings indicate that the asymptomatic subjects with Chagas' disease had a normal work capacity and were not affected by high altitude.

Adult↗
PubMed1986

Turbidimetry of rheumatoid factor in serum with a centrifugal analyzer.

We describe the simple, rapid turbidimetry of IgM rheumatoid factor in human serum by use of the Cobas-Bio centrifugal analyzer. Heat-aggregated human IgG is used as the antigen. The immunoturbidimetric reaction is monitored at 340 nm for 300 s, and the changes in absorbance after the antigen is added are used to prepare the standard curve. Test results are calculated from the stored curve and reported in int. units/mL, based on comparison with the WHO reference serum for rheumatoid factor. There is no interference from bilirubin (up to 340 mumol/L) or hemoglobin (up to 5600 mg/L). Serum samples with a triglyceride concentration greater than 2.20 mmol/L must be cleared of lipids before analysis. The standard curve is linear from 30 to 500 int. units/mL. Precision, accuracy, linearity, and sensitivity are quite acceptable. The CV was generally less than 5% for different concentrations of rheumatoid factor. Results agree well with those by a rate-nephelometric procedure on the Beckman ICS system (rs = 0.932). However, both correlate poorly with a modified classical Waaler-Rose test. Of 47 patients with rheumatoid arthritis, 34 had IgM rheumatoid factor in their serum, but the measured value did not reflect the activity of the disease.

Adult↗
PubMed1985

Measurement of urinary catecholamines and their catechol metabolites and precursor by liquid chromatography with column-switching and on-line fluorimetric and electrochemical detection.

A new method is described for the determination of catecholamines and their precursor (3,4-dihydroxyphenylalanine), and separately of their catechol metabolites (3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylethylene glycol and 3,4-dihydroxyphenylethanol) in urine. After a two-step pretreatment involving ethyl acetate extraction and adsorption onto alumina, the separation is performed by ion-pair reversed-phase high-performance liquid chromatography. A column-switching system enables complete separation of the most polar compounds without increase in the total analysis time. The column eluates are monitored with both fluorimetric and amperometric detectors, the relative responses of which are used as an index of peak purity. Reference values for twelve healthy adults are given.

Adult↗
PubMed1985

Major surface protein of Toxoplasma gondii (p30) contains an immunodominant region with repetitive epitopes.

Four monoclonal antibodies (mAb) against surface antigens of tachyzoites of Toxoplasma gondii were produced. Immunoprecipitation of extracts of 125I-labeled tachyzoites identified the same polypeptide with apparent molecular weight of 30 000 (p30). A competition binding assay indicated that a single region of p30 was recognized by all 4 of the mAb. Furthermore, we found that single mAb inhibited 25-50% of the specific binding of antibodies of patients with toxoplasmosis to the antigenic extract of tachyzoites. It appears, therefore, that p30 is the most immunogenic constituent of tachyzoites, and that a single region of this molecule contains most of the immunogenic activity. Finally, a two-site/one-antibody immunoradiometric assay with the same mAb indicated that the p30 molecule is multivalent with respect to the expression of a single epitope.

Animals↗
PubMed1985

Toxoplasma gondii: redistribution of monoclonal antibodies on tachyzoites during host cell invasion.

Immunodetection of protein P30, a major surface antigen of Toxoplasma gondii tachyzoites, by a specific monoclonal antibody has demonstrated a homogenous distribution of this antigen on the surface of intra- and extracellular tachyzoites at all stages of their endodyogenic development. On living zoites, no redistribution of anti-P30 was obtained, contrasting with the capping obtained with antiserum to T. gondii. Upon invasion of a host cell, however, most of the coat of anti-P30 was shed from preincubated zoites at the level of the moving junction governing the entry of the parasite into the host cell.

Animals↗
PubMed1985

Influence of hormones and undernutrition on brain development in newborn rats.

High L-thyroxine (T4) and cortisol doses given to rats during the first 8 days of life and on the first day only respectively, produce decrease of body and brain weight and perturbances to brain energy substrates, i.e. glucose and ketone bodies. The same alterations are found in the undernourished rats from the prenatal period. The pituitary GH and TSH is decreased in the T4- and cortisol-injected animals. The plasma ACTH is decreased in the treated cortisol animals at 8, 12 and 22 days of life. The pituitary TSH content is reduced with respect to controls in the undernourished animals from 14 to 70 days of life. From the exposed experiments we suggest an alteration in the hypothalamic-pituitary complex in T4- and cortisol-treated rats, and describe the similarities between the three experimental models.

Aging↗
PubMed1984

Different monoclonal antibodies against the component 5 specific for Trypanosoma cruzi.

Three murine monoclonal antibodies (I-35/67, II-190/30, III-160/18) produced by immunization against total epimastigote extract or component 5-enriched fractions of Trypanosoma cruzi (Tehuantepec strain) have been demonstrated to recognize the component 5 specific for T. cruzi. By immunofluorescence studies, one of these monoclonal antibodies (I-35/67) was shown to bind to the epimastigote cell surface, and the two others (II-190/30 III-160/18) were preferentially directed against internal subcellular organelles. Immunoprecipitation using these monoclonal antibodies followed by SDS-PAGE analysis, has led to identification of four molecules with apparent molecular weights of 72 Kd, 51 Kd, 43 Kd, and 24 Kd in T. cruzi epimastigotes. Potential uses of these monoclonal antibodies in serological tests and immunochemical analysis of target antigens are discussed.

Animals↗
PubMed1983

'Osmosin' in rheumatoid arthritis: interim results.

The interim results of an on-going trial in patients with active rheumatoid arthritis are reported. The findings from 17 patients so far treated and followed-up for 4 to 6 weeks suggest that 'Osmosin' (105 mg sodium indomethacin trihydrate), given once daily for the first 2 weeks and twice daily thereafter, is effective in reducing the inflammatory activity of joint disease, as assessed by visual analogue and 5-point semantic severity scales. Analysis showed that there was a strong association between the assessments on the two scales and this was stronger if patients were not conditioned by being allowed to see their previous visual analogue scale assessment.

Arthritis, Rheumatoid↗
PubMed1983

Testing of two score systems for the diagnosis of malnutrition.

Two score systems, one for the diagnosis of obesity and another for diagnosing undernutrition were tested in thirteen overweight and seven underweight children aged five years and preliminarily classified as malnourished. These score-systems included indicators grouped into three categories, those which evaluate total body mass changes (one-point group); those which assess fatness (two-point group); and those which assess fatness and/or body composition through complex indices (three-point group). Indicators such as Energy/Protein Index, AKS Index, Somatotype ratings, and Somatotype Dispersion Distances were included in the third group and played an important role in the final score. A subject was classified as malnourished if he reached 80% of the maximum possible score. According to these criteria, only six among the thirteen overweight children could be considered obese and none of the seven underweight ones could be classified as undernourished. Mild or moderate overweight or underweight may be misleading and an incorrect diagnosis of either obesity or undernutrition can be made if the possibility of constitutional corpulence or thinness is not taken into account.

Anthropometry↗
PubMed1982

[Production of monoclonal antibody anti-antigen 5 for Trypanosoma cruzi].

Monoclonal antibodies against Trypanosoma cruzi have been produced by fusion of Sp 2/0 myeloma cells and splenic lymphocytes from BALB/c Mice immunized with a T. cruzi antigenic fraction. Antigenic studies of these monoclonal antibodies have led to the identification of IgG 1 antibody against the component 5 specific for T. cruzi (cellular clone II 190/151). These monoclonal antibodies will give rise not only to new diagnostic and epidemiological perspectives but will also aid in achieving a better understanding of the biological role of this antigen.

Animals↗
PubMed1982

Total and cell wall phosphorus content in Bacillus megaterium in phosphate-limited media.

A comparative study of the amount of total and cell wall phosphorus in Bacillus megaterium ATCC 33085, grown in media with or without phosphate limitation was carried out. The phosphorus levels were investigated during six successive subcultures. A progressive decrease in total phosphorus was found in cells cultivated in a phosphate-limited medium. A decline in the cell wall phosphorus level was observed starting only from the third subculture in phosphate-limited medium, and no phosphorus was detected in the walls of cells in the fifth subculture.

Agar↗
PubMed1982

Assessing obesity with body weight and height.

Anthropometric measurements in one hundred girls and one hundred boys from 4.6 to 5.5 years of age were carried out in order to study the correspondence between the criteria of obesity according to weight for stature (BW-HT) and according to the magnitude of fat body mass (FM calculated of two different regression equations, one developed starting from body weight (BW), height (HT) and two skinfolds, and another one, using only BW and HT. Employing the criterion of obesity based upon BW-HT above 120%, a number of heavy but not fatty subjects (mainly boys) were included as obese, and three of the girls studied were fatty but not overweight. Conversely, if we calculate FM using the regression equation based on BW and HT, and the criterion of obesity based upon body fat percent, the incidence of obesity could be underestimated. The best results were given by regression equations which include BW, HT and two skinfolds (triceps and subscapular). Though the usefulness of BW and HT in nutritional assessment is not discussed, the diagnostic limitations of these measurements used alone or in combination are evident and therefore it is necessary to include skinfold measurements if we wish to obtain a correct diagnosis of obesity.

Adipose Tissue↗
PubMed1982

Rapid learning of visual and auditory spatial task in binocularly deprived cats.

Visually deprived and non-deprived cats were trained in a task involving a directional alimentary response spatially contiguous with a visual or an auditory cue. Both visual and auditory tasks were learned much faster by deprived cats. In these cats targeting reflexes evoked by the cues were stronger. When the modality of the cue was changed (from visual into auditory or vice versa), the learning was rapid in both non-deprived and deprived cats.

Animals↗