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Biomedical subjects

A Lopez

Publications and source records attributed to A Lopez.

At least 271 records · Page 15Linked to original sources
PubMed1986

Effect of sex, age, number of bronchoalveolar lavages and quantitation methods on the bronchoalveolar cell counts in rats.

This study was conducted to investigate the effect of sex, age, number of bronchoalveolar lavages and method of quantitation on the number of bronchoalveolar cells in rats. Forty Long Evans rats were divided into four age-sex subgroups of ten animals each. Nine consecutive bronchoalveolar lavages were done in every rat and the number of bronchoalveolar cells/mL in lavages 1-3 (L1), 4-6 (L2) and 7-9 (L3) were determined by hemocytometer and electronic cell counts (Coulter Counter). The sex or age of the rats did not show a significant effect (p less than 0.05) in the number of bronchoalveolar cells recovered from the lungs; however, there was a significant difference (p less than 0.05) in the number of cells/mL among lavages 1-3, 4-6 and 7-9 (L1 approximately equal to L2 greater than L3). A discrepancy of approximately 8% in the counts of bronchoalveolar cells was found between the hemocytometer and the Coulter Counter; however, these two methods of cell quantitation showed a significant (p less than 0.01) positive correlation (r = 0.89). No significant (p greater than 0.05) differences were found in the percentage of fluid recovery (overall mean = 94.5%) among lavages L1, L2 and L3. It was concluded that the electronic cell counting of bronchoalveolar cells is as reliable as manual counting. Although sex or age did not significantly affect the number of cells recovered from the lung, caution should be used in the number of lavages done per rat since this variable may significantly affect the results.

Age Factors↗
PubMed1986

Effect of sex and age on the activities of lactate dehydrogenase and alkaline phosphatase in the lungs of rats.

Since toxicity studies among different laboratories generally involve rats of different sex and age, this study was conducted to investigate the effect of sex, age and animal to animal variation in the activities of lactate dehydrogenase and alkaline phosphatase from bronchoalveolar lavage fluid, bronchoalveolar cell lysate and lung homogenate. Correlation between numbers of bronchoalveolar cells recovered from lungs and enzyme activity in bronchoalveolar cell lysate or lung homogenate supernatant were also investigated. Male rats showed significantly (p less than 0.05) higher activities of alkaline phosphatase in the bronchoalveolar lavage fluid and lung homogenate. Animal to animal variation for lactate dehydrogenase and alkaline phosphatase was higher in lungs than in serum. The number of bronchoalveolar cells recovered from lungs revealed a significant (p less than 0.01) positive correlation with the activities of both enzymes in the supernatant of cell lysates but not in the bronchoalveolar fluid. These results indicated that in an inhalation study interindividual variation in the levels of pulmonary enzymes should be considered in order to minimize the numerous possible sources of experimental error.

Age Factors↗
PubMed1985

The binding of [3H]oestradiol-receptor complex to hypothalamic chromatin of male and female mice.

Histones and masking acidic proteins were removed from hypothalamic chromatin in order to evaluate/measure the number of available acceptor sites for the [3H]oestradiol-receptor complex. This number increases after dehistonizing and unmasking and is lower than published values for comparable preparations. No sex-related difference in [3H]oestradiol-receptor binding to hypothalamic chromatin in vitro was observed. Failure to observe such a difference suggests that sexual differentiation and steroid sensitivity cannot be attributed to marked differences in the degree of chromatin masking.

Animals↗
PubMed1985

Symptomatic root compression by a free fat transplant after hemilaminectomy. Case report.

The authors report a case in which a free fat graft, placed at the operative site after hemilaminectomy for lumbar disc herniation, was forced into the spinal canal by action of the paraspinal muscles and behaved as a symptomatic space-occupying lesion. The patient recovered satisfactorily after the graft was removed. The pathogenetic mechanism is discussed and guidelines to avoid this complication are outlined.

Adipose Tissue↗
PubMed1985

[Comparative study between alkaline phosphatase and gamma-glutamyltranspeptidase in the diagnosis of hepatic metastases].

Diagnostic values of alkaline phosphatases (AP) and gamma-glutamyl-transpeptidase (GGT) in hepatic metastases were compared in 48 patients with digestive carcinomas. The study was a prospective one conducted under blind conditions. The AP was less sensitive (0.50) than the GGT (0.86) but was more specific (0.96 as against 0.88). Diagnostic value of GGT (0.87) was therefore greater than of AP (0.75). Positive predictive value of AP was 0.70 and of GGT 0.57. The risk of detecting hepatic metastases was 9% if the AP was normal and 2% if the GGT was normal.

Adult↗
PubMed1985

Correlations of values of micronutrients in sera with gastric pathology.

Sera were collected in a high-risk area for stomach cancer in Colombia from 857 residents who had been gastroscoped. The levels of 6 micronutrients (retinol, beta-carotene, ascorbic acid, vitamin E, prealbumin, retinol-binding protein) were measured and the mean values correlated with the presence of gastric pathology thought to represent precursors of stomach cancer. Two micronutrients showed important variations in mean levels by gastric pathology: beta-carotene and vitamin E. Beta-carotene levels were low in patients with dysplasia, but no differences were detected for retinol levels.

Adolescent↗
PubMed1985

Complete urinary excretion profile of 5-fluorouracil during a six-day chemotherapeutic schedule, as resolved by 19F nuclear magnetic resonance.

We determined the urinary excretion of 5-fluorouracil (5FU) and its metabolites during six days of chemotherapy, using the non-invasive approach of 19F nuclear magnetic resonance. With this method, which requires no labeled drug, one can study the biological sample directly and simultaneously identify and quantify all the fluorinated metabolites. The daily urinary excretion of 5FU and its metabolites was high (94.8% of 5FU administered) and nearly constant all during the treatment. By far the major excreted catabolite was alpha-fluoro-beta-alanine, which made up 78.9% of the total. Unchanged 5FU (10.8% of dose injected) was found only during the first 2 h after injection. We observed neither accumulation of 5FU nor modifications in its metabolism during the treatment.

Fluorine↗
PubMed1984

New approach to metabolism of 5'-deoxy-5-fluorouridine in humans with fluorine-19 NMR.

The metabolism of 5'-deoxy-5-fluorouridine (5'dFUrd), an antitumor fluoropyrimidine, has been investigated in human biofluids (blood, plasma, urine) using a new method: fluorine-19 NMR spectrometry. This method allows direct study of the biological sample and simultaneous identification of all the fluorinated metabolites. In the blood of a patient treated with 5'dFUrd during a 6-h continuous perfusion, we observed unmetabolized 5'dFUrd, 5-fluorouracil, 5,6-dihydrofluorouracil, and another metabolite which has not previously been reported alpha-fluoro-beta-alanine. The two major metabolites in urine are unmetabolized 5'dFUrd and alpha-fluoro-beta-alanine.

Antineoplastic Agents↗
PubMed1984

Modification of plant proteins by immobilized proteases.

A potential application of plant proteins could be a replacement of animal proteins now in use in the food industry on the basis of certain specific functional properties plant proteins have. Modification of the chemical structure of selected plant proteins is needed to replace more expensive animal proteins as food ingredients that have specific functional characteristics. Structure modification may be achieved by physical, chemical, or microbiological methods, or by a combination of these. Immobilized enzyme techniques offer significant advantages for protein modification. Knowledge of the molecular properties of plant proteins is essential to understand the basis of protein functionality, to modify proteins so that they acquire desirable functional properties, and to predict potential applications of modified plant proteins. This paper reviews all the above mentioned aspects of plant protein chemistry and potential utilization.

Amino Acids↗
PubMed1984

Effects of polyamines on platelet aggregation.

Polyamines, spermine and spermidine in the micromolar range (1-100 mumol/l) increase ADP and epinephrine-induced platelet aggregation in vitro. The possible rôle of polyamines as regulating factors of platelet aggregation in physiological and pathological states is discussed.

Adenosine Diphosphate↗
PubMed1984

Fluosol 43 intravascular persistence in mice measured by 19F nmr.

Quantitative determination of the intravascular persistence of F-tri-n-butylamine (FC 43 as Fluosol 43) in mice was carried out using 19F nmr spectroscopy. The method allows the direct study of whole blood, neither separation nor extraction of the sample being required. Accuracy (reproducibility) is better than +/- 3%, and is comparable to that of the gas chromatographic (gc) method. The sensitivity of detection is less than that of the gc method but is sufficient for this biological study. It was observed that the intravascular elimination of F-tri-n-butylamine follows a non-linear kinetic and becomes faster about 40 h after the injection. This phenomenon may be explained by the size-increase of the FC 43 droplets in the emulsion. Indeed, at about 40 h after injection, the level of Pluronic F-68 in the bloodstream was no longer sufficient to maintain the stability of the FC-43 droplets. They therefore tended to coalesce forming larger droplets that were phagocytosed more rapidly by the histiocytes of the reticuloendothelial system.

Animals↗
PubMed1984

Effects of long-term amiodarone treatment on thyroid function.

Serum determinations of total T4, total T3, reverse T3, free T3 index, free T4, free T4 index, TBG, T4/TBG ratio, TSH and cholesterol were carried out on 18 euthyroid patients with coronary heart disease. Serum samples were obtained before treatment and after 15 days, 2, 4, 6, 8, 10, 12, 14 and 16 months of treatment with amiodarone (400 mg/day). Patients were divided into two groups, according to patterns of TSH response to thyrotrophin-releasing hormone (TRH): (I) patients with normal responses (n = 12), and (II) patients with subnormal responses (n = 6). Patients of group I showed total T4, free T4 and reverse T3 increments and total T3 and free T3 index decreases, whereas patients of group II were distinguished by the absence of T3 decreases and a rise in free T4 levels that showed a significant correlation with a drop in serum cholesterol (r = -0.767; p. less than 0.001). No patient of either group showed clinical signs of thyroid dysfunction. These results show that the appearance of hormonal patterns of hyperthyroidism is unpredictable and very frequent in patients with no previous thyroid abnormalities undergoing long-term treatment with the drug.

Aged↗
PubMed1984

[Scanning radiographic evaluation of cleft lip and palate].

The works of Paul Tessier, M.D., have shown the frequent association of facial and cranial clefts. After studying eleven cases of cleft palate which could be associated to encephalic anomalies, we conclude that we cannot systematize an evaluation by CAT-scan for low and isolated cleft palates. On the other hand, as soon as an association exists with: a psychomotor deficit (even slight); neurologic symptoms; a participation of the eye or the socket, the scanner evaluation becomes necessary.

Adolescent↗