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C Y Valenzuela

Publications and source records attributed to C Y Valenzuela.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Annual rhythm of menarche in Medellín, Colombia].

Hypotheses on seasonal, phylogenetic and ontogenetic factors or imprinting that may produce menarcheal rhythm were tested in a sample of school girls from Medellín, Colombia. The questionnaire included a net of important religious or national feasts and periods of vacation or study to prevent memory biases. European, Asian and Chilean samples showed peaks of menarche in December and January, but a few samples showed a second one in June, July and August. The winter short photoperiod and low temperature were assumed to be the cause of the winter peak in most European samples. However, this seasonal hypothesis was refuted when a Chilean sample also showed a peak in December, January and February (Summer). In the present study performed in a sample from a tropical country we found two peaks of menarche, one in July and the other in November, December and January; thus, the seasonal bypothesis can be hardly supported. Moreover, this sample showed a high coincidence between the month of menarche and the month of birth, and a different pattern of menarche when menarches are distributed according to their coincidence with the gestational development. Both facts affirm the ontogenetic hypothesis, because they were also found in several samples. Since this population is different from those already studied and its monthly distribution of menarches and births is also different from those other ones, the hypothetical phylogenetic factors find additional support. The possible influence of school stress and other environmental factors in the menarcheal rhythm are discussed.

Adolescent↗
PubMed1996

Gm and Km allotypes and typhoid fever.

Gm and Km allotypes of immunoglobulins were determined in children with typhoid fever (Cases), in children without infectious diseases (Con-1), and in children with fever but no Salmonella in their blood or bone marrow (Con-2). Children were sampled from the urban population of Santiago; and they belonged to the low and low-middle socioeconomic strata. Cases had a higher frequency of [f;(-);b1,b3 or 3;(-);5,13] G1m, G2m, G3m haplotype than Con-1 and Con-2. Con-1 and Con-2 did not differ in their Gm haplotype or Km allele frequencies, but they differed in phenotype distribution. Con-1 deviated from Hardy-Weinberg equilibrium for Km due to a lack of Km 1-1 homozygotes. The relationship among these results, the ethnic origin of Chileans, and the differential susceptibility to typhoid fever are discussed.

Adolescent↗
PubMed1996

Idiopathic epilepsy with generalized tonic clonic seizures in Antioquia, Colombia: is the joint Amerindian and Negroid racial admixture the cause of its high prevalence?

Most Colombian populations stem from the admixture of Caucasians, Amerindians and Negroids. In the world, these two latter ethnical groups show a significantly higher prevalence of epilepsy than the former one. We tested the hypothesis that the high prevalence of idiopathic epilepsy with generalized tonic clonic seizures found in the Antioquian population (Paisas), from Colombia, is due to their possible joint Negroid and Amerindian ethnic components. We have previously demonstrated that inheritance is the principal factor for developing epilepsy in this community. Analyses of racial admixture, heterogeneity between populations, genetic distance, and phyletic relationships were performed among epileptic and non epileptic samples from the Antioquian community. Also Caucasians, Spaniards, Basques, Jews, Chileans, Negroids, Amerindians and Mongoloids were included in the analysis. Four highly polymorphic blood systems were used as genetic markers: RH, MNS, ABO and FY. They were chosen because of their high discriminant power in these ethnic groups. In the population affected with idiopathic epilepsy, the estimated Negroid and Amerindian rates of admixture were low (3% and 14%, respectively). Although, these degrees of admixture can be explained due to common ancestral origins, the estimated proportion of Amerindian admixture in the epileptic affected population, was significantly higher than the estimated for the Non affected Antioquian population. The latter finding is consistent with the analysis of heterogeneity between populations that discriminated epileptic population from non epileptic Antioquian population (p < 0.05). Epileptic and non epileptic Paisas clustered in topology with Caucasians, very close to Spaniards and Basques and highly distant from Negroids and Amerindians. Thus, far, the origin of the high prevalence of idiopathic epilepsy in the Antioquian (Paisa) population cannot be explained by the hypothetical joint Negroid and Amerindian ethnical admixture, but using additional genetic markers and other methods of racial estimation of admixture it is necessary to corroborate if the Amerindian admixture component is significantly higher in the epileptic population than in the non epileptic Paisa population.

Black People↗
PubMed1996

A model of complete random molecular evolution by recurrent mutation.

A model for random molecular evolution based on recurrent mutation is proposed. Recurrent mutation replaces completely any original base in a nucleotidic site. This occurs if more than four times the number of reproductive cycles equal to the reciprocal of the mutation rate happen; no matter the population size, the number of nucleotides a genome has, or the taxa at which it belongs. The main results are: i) the expected distribution of DNA bases in a site is an isotetranomial distribution, where Adenine (A), Guanine (G), Cytosine (C) and Thymine (T) occur with probability equal to 0.25; ii) the distribution of bases in a site is independent from the distribution of bases in other sites. Several expected consequences that can be contrasted with actual data are generated. Species or operational taxonomic units (OTUs) that evolved in big populations should present distances equal to zero and similarities equal to one. OTUs evolving in small populations should present distances equal to 3/4 and similarities equal to 1/4. Thus, random molecular evolution by recurrent mutation cannot yield a tree at all. The only possible tree is that produced by random fluctuations of distances according to their variances (stochastic tree). Some consequences of the model on the expected primary structure of proteins are also analyzed. There are sufficient generations for any DNA segment evolving apart during the last four hundred million years, to reach those expected base distributions.

Chymotrypsinogen↗
PubMed1996

New evidence of non seasonal factors in the menarche rhythm.

The phylogenetic, ontogenetic and seasonal hypotheses on the annual periodicity of menarche were tested. Data from European, Asian (Caucasian, Mongolian and Caucaso-Mongolian people from the northern hemisphere) and Chilean (Caucaso-Amerindian from the southern hemisphere) populations were compared with data from Hungary (Caucaso-Mongolian Europeans from a northern temperature zone) and Madras, India (a complex ethnically originated people from a tropical northern area). Chileans were compared with those Caucaso-Mongolian people because Amerindians belong also to the Mongolian group. Hungarian girls showed peaks of menarche in the month of January (winter), June, July and August (summer), in contradiction with most European Caucasians who showed peaks only in winter months; and in agreement with Finns who showed both peaks. Indian girls had peaks in April, May and June (summer) and more extreme peaks and troughs than the Finnish girls (from a temperature arctic zone). These findings do not agree with the seasonal hypothesis, but they do with the phylogenetic hypothesis. Indian girls had a peak of menarche in the same month of birth and the arrangement of data according to the gestational-menarche coincidence showed a significant heterogeneity for the monthly peaks of menarche; thus, the ontogenetic hypothesis was also supported.

Adolescent↗
PubMed1995

Rh--plasma iron binding capacity association. New evidence.

The relationship between Rh phenotypes and the total iron binding capacity (TIBC) of plasma was studied in a sample from Medellín, Colombia. In a previous report from Santiago, Chile, children carrying the C Rh specificity had a higher level of TIBC than those having the specificity. The same association was found in young people from Medellín.

Chile↗
PubMed1994

Epistemic restrictions in population biology.

Biologists have believed that the application of statistical or mathematical models to population biology has always been a correct and helpful tool to acquire knowledge. The present article demonstrates that the standard interpretation of statistical results yielded by the application of mathematical models to some populational processes, not only hides knowledge, but may lead to wrong knowledge. These epistemic restrictions (type I and II errors). A new more versatile conditional interpretation of statistical results is proposed.

Genetics, Population↗
PubMed1993

[Psychosocial sexual phenotypes. A proposition and their ontogeny].

A proposition of operational phenotypes and ontogeny for psychic and social sex is presented. These phenotypes are defined according to the three major theories of Biology: cell, inheritance and evolution. Sexuality is defined, for species, as the ability to produce individuals in creative genetical process by means of genetical recombination associated with reproduction. Sex is defined, for individuals, as the set of characters (phenotypes) that allow those gene recombinative and reproductive processes. The Psychic Sex includes: the Sexual configuration of identity, the Sexual appetizing configuration, the Genital connection, the Somatoerogenic connection, the Integration of psychic sex into personality and the Sexual psychomotor form. The Social sex includes those individual behaviors performed isolately or collectively that realize sexual processes in the species. The ontogeny of these phenotypes considers that they are the product of the interaction between the genotypes and environments. The endogenous neuroendocrine differentiation, mainly due to genetic factors., interacts with the familial and social environment, which presents a set of sexual polar semiotic factors. The endogenous differentiation makes more or less probable to acquire further sexual differentiations yielded by co-living (interactions that are brought about by living together) with that differentiator (that produces differentiation) polar environment.

Genetics, Medical↗
PubMed1992

[Typhoid fever in children: association with blood phenotypes ABO, Rh and MNSs].

The hypothesis that blood phenotype B is associated to typhoid fever either directly or interacting with other phenotypes of the Rh or MNSs blood systems was tested. 256 children from the Northern Area of Santiago (Chile) with bacteriologically confirmed typhoid fever and 329 afebrile controls matched by age and gender from the same population, were studied. Association was found between phenotype RH3 and protection against disease for the whole group (OR = 0.67; p < 0.042) and for males (OR = 0.05; p = 0.014) although the gender-RH3 interaction was at the limit of significance. RH8 and Ss phenotypes were associated to increased susceptibility (OR = 1.83; p < 0.034 and OR = 1.56; p = 0.01, respectively). Controlling RH3 and Ss phenotypes by B, increased their effects (OR = 0.26; p = 0.04 and OR = 3.42; p = 0.026, respectively), but interactions did not reach statistical significance. These results show a susceptibility cline whose implications and applicability deserve further studies. A high proportion of S. paratyphi B (23.8%) appeared in this series, which may imply sample heterogeneity. The meaning of these findings need further epidemiological and genetic studies.

Blood Group Antigens↗
PubMed1992

[Study of the Widal test phenotypic expression of blood groups ABO, Rh and MNSs in patients with typhoid fever].

The significance of the Widal test (WT) as a phenotypical expression was investigated in a cross-sectional study of 244 children from the Northern Area of Santiago (Chile) with bacteriologically confirmed typhoid fever (TF) due to S. typhi (183 cases) and S. paratyphi B (61 cases). The working hypothesis was that if the parasite-host relationships were similar for these two agents the immune response, as measured by the Widal test, should be similar. An association between test response and etiology was found consisting of a significantly higher proportion of positive response, in cases due to S. paratyphi B as compared with those due to S. typhi, (OR = 2.13; 95 Cl% = 1.06, 4.32; p = 0.02). Stratified analysis showed that although the association between etiologic agent and Widal test response persisted within all strata, significant interactions could be shown as evidenced by the magnitude of the associations, which varied according to blood phenotypes as well as gender (Mantel-Haenszel test for heterogeneity for 0, p < 0.034; for RH5 p < 0.033; for SS, ss p < 0.056; and gender p < 0.033). These results support the hypothesis that the Widal test response is a phenotypical marker eventually useful for studying human genetic heterogeneity in typhoid fever. The implications of these findings regarding previous study results and the possible role of S. paratyphi B in typhoid fever and its related conditions are discussed.

Adolescent↗
PubMed1992

ABO segregation distortion in Visakhapatnam, India.

Distortions in mother-infant, mother-child and father-child segregation for the ABO system as well as in the sex of offspring are described in a sample from a maternity service and from families of Visakhapatnam, India. Some distortions follow the expected fetomaternal incompatibility depression, others the expected feto-maternal induction of tolerance, and some remain unexplained. A differential action of selective factors on male and female fetuses, infants and children was also found, but no hypothesis could be postulated to explain it. The mother-infant matrix was found to be different from the mother-child matrix probably due to the inclusion of the reproductive time only in the mother-infant matrix. Unexpectedly, father-child segregation distortions were also found.

ABO Blood-Group System↗
PubMed1991

Association between Rh and plasma iron binding (transferrin).

In order to establish the mechanism involved in the maintenance of the Rh polymorphism and fetomaternal compatibility relationships, we examined a sample of children from the North Area of Santiago (Chile), with respect to their growth and development patterns since 1973. This sample had shown large sib-sib segregation distortions for the Rh system. Metric variables, such as plasma protein fractions and iron, academic performance at the end of the last secondary grade and adult stature, were studied in relation to genetic markers, viz., sex, ABO, Xg, MN, Rh, haptoglobins, phosphoglucomutase, and esterase D, by means of unbalanced one way analyses of variance. Highly significant results were found for Rh phenotypes and total iron binding capacity (TIBC, transferrin). However, plasma iron did not differ significantly among Ph phenotypes. Children with the C (Rh) specificity had higher values of TIBC than non-C or c individuals (P less than 0.00001). Evolutionary considerations regarding iron transport and erythroblastosis, relationships between Rh and the transferrin receptor at the plasma membrane, and the location of the Blym-I oncogene (that shares common sequences with transferrins) close to Rh in chromosome 1 are discussed. Less significant results were found between phosphoglucomutase and stature, gamma globulin level and sex, and academic performance (history) and sex.

Analysis of Variance↗
PubMed1991

Segregation distortions of the ABO and Rh systems in malformed newborns.

This study compares the segregation of the ABO and Rh systems between malformed newborns and a control group with two purposes: (1) to evaluate the participation of genetic factors associated with these blood groups in the production of congenital malformations, and (2) to prove, indirectly, the existence of reproductive losses associated with congenital malformations. The newborns and their mothers were typed for ABO and Rh groups. Gene frequencies were similar in malformed and control newborns. In the female malformed newborns, an excess of O-B pairs and a deficit of B-B pairs in the ABO system, and an excess of Rh(-)-Rh- pairs in the Rh system were found.

ABO Blood-Group System↗