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Biomedical subjects

R Blanco

Publications and source records attributed to R Blanco.

At least 181 records · Page 10Linked to original sources
PubMed1985

Estriol radioimmunoassay in plasma and urine.

A specific radioimmunoassay of estriol has been developed using an antiserum obtained by immunization of rabbits against 1,3,5 (10)-Estratrien -3, 16 alpha 17 beta-triol-6 one 6 carboximethyl oxime: BAS (Estriol 6-CMO-BSA). The tracer used was Estriol (2, 4, 6, 4, 3H (N)). This assay does not require prior hydrolysis, extraction or purification. Either plasma, serum or urine can be used. Urine only requires 100 microliter (1:5) dilution and 100 microliter in serum or plasma. An incubation time of 60 minutes is requires; a linear standard curve is obtained by logit-log extrapolation and a good correlation was obtained (r = 0.063) with estriol determination by comparison to a generally accepted colorimetric method. The detection range is from 100 pg to 50,000 pg in plasma or serum and urine. The specificity of the antibody was determined by studies of cross reactivity with other steroids. The sensitivity (100 pg) and accuracy were proven to be highly satisfactory. This method is simple, rapid and accurate.

Animals↗
PubMed1984

Fibrinogen and fibrin interaction with concanavalin A dimer and its influence on coagulation.

Concanavalin A dimer interacts with fibrinogen and soluble fibrin at pH 5.2 Analysis of the binding data shows that there are in both cases four binding sites per molecule and that the dissociation constant does not change by removal of fibrinopeptides A and B. Ultracentrifugal studies show that no aggregates of fibrinogen or fibrin are formed through concanavalin A binding and that up to four molecules of concanavalin A dimer can bind to one molecule of fibrinogen or fibrin. These results imply that the four carbohydrate chains in the molecule are accessible to concanavalin A dimer. There is a diminution in the coagulation of fibrinogen by thrombin at low relative lectin concentrations and an increase at high concentrations. However, the lectin always favours the aggregation of fibrin monomers and does not have any inhibitory effect on the release of fibrinopeptides. We conclude that the electric charge in the neighbourhood of the carbohydrate in both chains, B beta and gamma plays an important role in the attraction between monomeric fibrin and fibrinogen-monomeric fibrin. The different effect of concanavalin A on the coagulation, depending on the relative concentration of the lectin, would be the result of the screening of this electric charge favouring either the interaction of fibrinogen-monomeric fibrin or the polymerization of monomeric fibrin.

Blood Coagulation↗
PubMed1979

A requirement for ATP for beta-galactoside transport by Bacillus alcalophilus.

Lactose-grown cells of Bacillus alcalophilus actively transported methylthio-beta, D-galactoside (TMG) in a range of pH values from 7.5 to 10.5 with a pH optimum at 8.5. The TMG was accumulated in a chemically unmodified form, and cell extracts failed to catalyze either ATP or P-enolpyruvate-dependent phosphorylation of TMG. At pH 8.5, the lactose-grown cells exhibited a transmembrane proton gradient (deltapH) of 1.38 units, interior acid, and a transmembrane electrical potential (delta psi) of -132 mV. Accordingly, the total protonmotive force at this pH was very low, -51mV. Several lines of evidence indicate that the protonmotive force or delta psi did not directly energize TMG transport but, rather, that ATP was directly required: (a) in cells treated with arsenate so that the delta psi was unaffected and cellular ATP levels were markedly lowered, TMG transport was inhibited in proportion to the reduction of cellular ATP, while electrogenic alpha-aminoisobutyric acid transport was not; (b) when a valinomycin-induced potassium diffusion potential was established in starved cells, alpha-aminoisobutyric acid transport, but not TMG transport, was stimulated; and (c) in a series of experiments in which the delta psi was rapidly abolished by treatment with gramicidin, ATP levels declined slowly and the rate of TMG transport correlated directly with ATP levels rather than with the delta psi. Consumption of cellular ATP concomitant with TMG transport could be demonstrated.

Adenosine Triphosphate↗
PubMed1976

The genetics of shovel shape in maxillary central incisors in man.

From dental casts of 94 parent-offspring and 127 full-sib pairs, sampled from two Chilean populations, shovelling indices are computed to measure the degree of shovelling of maxillary central incisors quantitatively. Genetic correlations are computed to determine the role of genetic factors in explaining the variation in this trait. Assuming only hereditary factors to be responsible for the transmission of shovel shape, 68% of total variability is ascribed to the additive effect of genes.

Anthropology, Physical↗
PubMed1976

Malignant duodenocolic fistula: report of two cases, each with one or more other synchronous gastointestinal cancers.

Two patients had duodenocolic fistulas, each following a carcinoma of the colon in the area of the hepatic flexure that had perforated into the duodenum. The first patient was treated by a radical pancreatoduodenectomy with right colectomy; the second by subtotal colectomy with excision of the duodenal wall and suture. Both patients are alive and without evidence of recurrent disease. In addition, the first patient had two other primary carcinomas, in the cecum and in the stomach, and the second patient had another primary in the sigmoid. The definitive procedure had to be adjusted to encompass all lesions. The radical operation in one stage seems to be the preferred procedure and certainly is most satisfactory as a cancer operation. Our patient treated by this procedure has survived more than 11 years. An intestinal fistula related to colonic carcinoma, evan though rare, should not be considered as a separate entity. Treatment of the cancer with an en-bloc resection of the communicating organs should be employed if possible.

Adenocarcinoma↗
PubMed1975

Genetic distance analysis of twenty-two South American Indian populations.

Extent of genic variability among 22 tribal groups of South American Indians in terms of net codon differences per locus has been studied on the basis of determinations on ten genetic systems. The possibility of more than one (other than the north-south route, considered by others) migrational pattern is discussed in the light of the existing genetic variability among the Andean highland and the jungle populations. Genic similarities (as measured by gene identity) are related with geographic proximities which reflect the importance of random genetic drift in creating the present genic divergence among these population groups. Although the materials used in this paper form probably only a non-random sample of structural genome, intralocus variance (sampling) is found to contribute only a little in the variabilities of heterozygosity or genetic distance.

Bolivia↗
PubMed1975

Consanguinity and demography in some Chilean populations.

Spatial and temporal changes in the rates and the patterns of consanguinity are studied in some (indigenous as well as admixed) populations of Chile. Relationship between the variation of infant mortality and late fetal death rates with the degree of inbreeding is also explored. The need of a temporal study of these demographic variables is also emphasized to elucidate the influence of marriage structure or determined reproductive patterns on the genetic and demographic aspects within these populations.

Birth Rate↗