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Biomedical subjects

A Castro

Publications and source records attributed to A Castro.

At least 523 records · Page 29Linked to original sources

H-1 and X14 parvovirus antibodies in women with abortions or still-births.

Antibodies against H-1 and X14 parvoviruses were found 13.71 and 9.14%, respectively, of 350 sera from women affected by repeated abortions or still-births. On the contrary, only 2.66 and 1.66% of 300 control sera were positive to the two viruses. The difference in the incidence of antibodies appears highly significant (p greater than 0.001). Therefore a possible role of the parvoviruses in inducing abortions or still-births in humans is suggested.

Abortion, Spontaneous↗

Comparative determination of phenytoin by spectrophotometry, gas chromatography, liquid chromatography, enzyme immunoassay, and radioimmunoassay.

Sera from patients being treated with phenytoin were analyzed for the drug by spectrophotometry, gas chromatography, radioimmunoassay, enzyme immunoassay, and liquid chromatography. The essay values obtained were intercompared statistically. Enzyme immunoassay and liquid chromatography appear to be attractive alternatives to the more traditional methods of spectrophotometry and gas chromatography. Our radioimmunoassay data correlated poorly with results by the four other methods.

Chromatography, Gas↗

A direct enzyme-linked immunosorbent assay (ELISA) for detection of antibodies for rubella virus in human sera.

A direct enzyme-linked immunoassay (ELISA), based on the "sandwich" principle on an antigen-coated plastic disc, was used for the rapid detection of rubella antibody. Results were obtained the same day, and the prior adsorption of sera to remove non-specific inhibitors was not necessary. The ELISA was compared to the hemagglutination-inhibition (HAI) test on 500 serum samples. There was general agreement between the two methods; most discrepancies occurred with low-titered HAI positive sera. There was excellent correlation between the tests with serum samples negative for rubella antibodies and those samples with HAI titers greater than or equal to 1:40.

Animals↗

Immunochemical studies of 5-bromodeoxyuridine.

Specific antibodies for BrdUrd and IdUrd have been produced and characterized by immunochemical studies. Studies as determined by hapten-inhibition showed a cross reactivity of less than 0.001% to thymidine, and no cross reactivity to bromodeoxycytidine, uridine or methyl cytosine. The equilibrium constant determination for anti-BrdU and IdUrd was 4.2 x 10(8)M-1. Unfractionated antiserum, produced under the conditions herein described, can be employed for the specific cytological detection of DNA replication.

Animals↗

A totally automated system for enzyme immunoassay of theophylline in serum.

We describe a procedure for enzyme immunoassay of theophylline (1,3-dimethylxanthine) in which all phases of the assay are totally automated in a Kinetic Analyzer (KA-150). This system permits assay of 75 10-mul samples per hour, with results available at 30-s intervals after initial sample preparation and preincubation. We compared results for 138 clinical samples by an ultraviolet method (x) and the present method (y). The slope of the comparison curve was 0.902, the y-intercept 0.402, and the correlation coefficient 0.984. The coefficient of variation for samples run in duplicate on the same day was 4.9%; it was 8.1% for samples run on different days. Specificity, sensitivity, simplicity, speed, and small reagent requirement all make this an attractive alternative to chromatographic procedures.

Autoanalysis↗

Comparison of prothrombin time and activated partial thromboplastin time on Dade Auto-FI and Bio-Quest Fibrometer.

Plasma assay results for prothrombin time and activated partial thromboplastin time obtained on the fully automated Dade Auto-FI were compared with those obtained on the more traditional semi-automated Bio-Quest Fibrometer. The precision data showed in a majority of cases the superior reproducibility of the Auto-FI over the fibrometer. However, we found that results of APTT utilizing both methodologies were not at present interchangeable.

Blood Coagulation Tests↗

Decreased rat hepatic guanylate cyclase activity in streptozotocin-induced diabetes mellitus.

Guanylate cyclase is found in virtually all cells, but its physiologic role and the effect of hormones on its activity have not been clarified. Hepatic soluble guanylate cyclase activity (37,000 g supernatant) in rats with diabetes-mellitus-like syndrome induced by streptozotocin, 65 mg./kg. i.v., was 140 +/- 8 pmoles accumulated/mg. protein/10 min. (n = 13 rats) as against 279 +/- 16 pmoles accumulated/mg. protein/10 min. (n = 12 rats) in normal rats. The average blood sugar for the 12 normal rats was 100 +/- 4 mg./100 ml. and 546 +/- 32 mg./100 ml. for 13 diabetic rats. The decreased soluble hepatic guanylate cyclase activity in diabetic rats was completely restored to normal with 10 U. regular insulin, i.p. The maximum increase in guanylate cyclase activity was observed as early as five minutes and as late as two hours after insulin administration. Insulin restoration of guanylate cyclase was dose-related over a range of 1 U. to 10 U., i.p. Hepatic cyclic GMP levels in vivo paralleled in-vitro guanylate cyclase activity, being 29 +/- 0.4 pmoles/gm. wet weight in normals, 17 +/- 0.4 pmoles/gm. wet weight in streptozotocin-diabetic rats, and 38 +/- 0.4 pmoles/gm. wet weight two hours after the injection of 10 U. regular insulin. We conclude that rat hepatic guanylate cyclase is decreased in streptozotocin-induced diabetes and that insulin modulates this enzyme. The administration of exogenous insulin in normal animals did not further augment hepatic guanylate cyclase activity.

Animals↗

Nucleic acid biosynthesis in rat embryo cells infected with X14 or H-1 parvovirus.

Nucleic acid biosynthesis was studied in rat embryo cell (REC) cultures 48 hours after infection with X14 or H-1 parvovirus. The incorporation of 14C-formate and [6-(14C]-orotic acid into purines and pyrimidines of various was lowered after infection with these parvoviruses. 14C-Formate incorporation into acid-soluble thymine was greatly inhibited in H-1 virus-infected cells whereas it was slightly inhibited in X14 virus-infected cells. These results suggest that X14 virus-infected cells can carry out the biosynthesis of thymidylic acid utilizing some endogenous pyrimidine nucleotide (e.g. deoxycytidylic acid, via deoxyuridylic acid). In the infected cells, the nucleoplasmic RNA polymerase activity was strongly inhibited. This results suggests an interference by the two viruses with hosts RNA synthesis.

Adenine↗

Enzyme immunoassay of hepatitis associated antigen (HAA).

Due to its high sensitivity, radioimmunoassay has become of great importance in the detection and measurement of levels of proteins and steroids in body fluids. However, this method involves the use of expensive equipment and radioactive material. Herein is described an alternate method to radioimmunoassay, which uses an enzyme-labeled rather than a radioactively-labeled antibody. An enzyme immunoassay procedure, the Cordia HAA-enzyme Immunoassay, for the detection of hepatitis-associated antigen has been evaluated. With this technique a sandwich type immunoassay with an alkaline phosphatase tagged second antibody is used. The presence of antigen is detected by the p-nitrophenyl phosphotase activity of the bound enzyme. In 1083 clinical samples from patients of Jackson Memorial Hospital, only 19 discrepant results were found when tested by both the Cordia and the Ausria II methods. Eight had sufficient sera for retesting, yielding two positive Cordia, negative Austia; one negative Cordia, positive Ausria; one borderline positive; and four unconfirmed false positives by Cordia.

Animals↗

Radioimmunoassays of drugs of abuse in humans: a review.

Only recently has radioimmunoassay been used for the detection of drugs of abuse in body fluids. While conventional assay methods are time-consuming, relatively insensitive, and require a larger sample volume, the radioimmunoassay method is rapid, sensitive, specific, and can be performed with a minimum of sample. Performance of individual assays is identical, and requires about 1 hour to complete. Herein are reviewed the radioimmunoassays which have been developed for measurement of drugs of abuse in humans. These new techniques are of importance in screening and in further research into the effect of these drugs on the functions of the human body.

Amphetamines↗

Serum biochemistry values in normal pygmy goats.

Blood serum of pygmy goats (both sexes, and castrated males) was analyzed to establish biochemical reference values. Influence of age on reference values was also studied. Serum biochemical analyses were made for urea nitrogen, creatinin, bilirubin, lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, glucose, uric acid, and total lipids. These serum values for pygmy goats were similar to those reported for man, except as follows: Aspartate aminotransferase activities were slightly higher than those reported for man. Glucose concentrations in pygmy goats were slightly lower than in human beings, and uric acid levels were significantly lower than the values for man. Female and castrated male goats had lower total lipid concentrations than did human beings, whereas intact males had higher concentrations. Thus, of the 9 measured variables for pygmy goats, 5 were comparable to human values. This, together with other attributes, including the small size which conduces to economics of maintenance and enhances the desirability of using pygmy goats in research.

Alkaline Phosphatase↗

Hematologic values in normal pygmy goats.

Pygmy goat blood was analyzed to determine hematologic base-line values. Male, female, and castrated male goats were used in this investigation. Influence of age on these variables was also studied. Most of the hematologic values of pygmy goats were similar to the reference values reported for several other ruminant species and for man. Values significantly different from reference values in man were as follows: Erythrocyte counts were slightly higher than for human beings. The relative lymphocyte count was comparable to that in infants, but significantly greater than values in adult human beings. Also, although not of statistical significance, hemoglobin levels in goats were slightly lower than in both infants and adult human beings, and the leukocyte count was just slightly higher than the usual values for infants and adult human beings. Thus, of 9 hematologic variables, only 1 was significantly different from those in man, and 2 were slightly different. The fact that pygmy goats have hematologic responses similar to those of man, and the similarity of hematologic values to reference values in man, further enhances the pygmy goat for use as an experimental animal.

Animals↗

Automated turbidimetry of amylase activity by use of a discrete kinetic analyzer.

We adopted an automated turbidimetric rate method for determining amylase activity to the KA-150 Kinetic Analyzer. In the method, an insoluble amylopectin substrate is used with activity determined by the rate of decrease in turbidity. Run-to-run CV for 59 samples with activities up to 400 units (arbitrary amylase units per 100 ml of sample) was 2.8%. A comparison with a similar method, performed by nephelometry, for 104 sera, showed a correlation coefficient (r) of 0.992, with a slope of 1.02. In an additional comparison with an amyloclastic method, for 52 sera r was 0.997, with a slope of 1.01. Day-to-day precision for control sera with activities near the upper limit of normal (279 and 216 units) averaged 2.5% during two months. Measured and calculated activity were linearly related to well above the upper limit of normal (normal range, 60-200 arbitrary units), showing a deviation from linearity of about 10% at 450 units. Commercial reagents available for the Perkin-Elmer Model 91 Amylase Lipase Analyzer can be used with the KA-150.

Amylases↗

Serum electrolytes in normal pygmy goats.

Serum from pygmy goats was analyzed to determine normal base lines for electrolytes. Animals of both sexes were used. Influence of age on these variables was also investigated. The electrolyte values were as follows: sodium, 147 +/- 6.0 mEq/L; potassium, 5.6 +/- 1.0 mEq/L; chloride, 106.0 +/- 4.2 mEq/L; calcium, 4.9 +/- 0.3 mEq/L; magnesium, 2.1 +/- 0.3 mEq/L; and inorganic phosphorus, 4.8 +/- 0.9 mEq/L. Most of the serum electrolyte values for pygmy goats were similar to reports for other ruminant species and human beings.

Aging↗

Serum proteins and protein electrophoretic pattern in normal pygmy goats.

The values of total protein and protein electrophoretic patterns for pygmy goats were studied to establish normal basic values. The values obtained in the present study were as follows: alpha1-globulin, 0.6 +/- 0.1 mg/dl; alpha2-globulin, 1.0 +/- 0.3 mg/dl; beta-globulin, 0.5 +/- 0.1 mg/dl; gamma-globulin, 1.6 +/- 0.1 mg/dl; total protein, 7.3 +/- 0.7 mg/dl; albumin, 3.2 +/- 0.6 mg/dl; A/G ratio, 0.8 +/- 0.3 mg/dl; and globulin, 4.5 +/- 0.6 mg/dl. Goats were divided into groups on the basis of age and sex to determine if any significant differences were present in these groups. Of the 8 variables studied, only albumin and A/G ratio showed significantly different values due to sex; castrated males showed significantly lower values than thos for intact males and females (P less than 0.05). Also, A/G ratio values for females and castrated male pygmy goats were significantly lower than those for intact males (P less than 0.05). Total serum protein values studied in female pygmy goats at various ages were also significantly different (P less than 0.05).

Aging↗