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Biomedical subjects

J E Bernal

Publications and source records attributed to J E Bernal.

18 recordsLinked to original sources
PubMed1992

Study of the etiology of deafness in an institutionalized population in Colombia.

To identify causative factors we screened 1,715 deaf individuals from 16 schools for the deaf in Colombia. We found evidence of environmental causation in 579 (33.8%) cases, genetic in 608 (35.4%), and in 528 (30.8%) we were unable to identify the etiology. The degree of hearing loss was severe to profound in 1,238 (72.2%), although in 987 (57.5%) of the deaf population studied the hearing impairment was not noticed until 2 to 5 years of age. The frequent association of deafness with other anomalies underscores the importance of a careful clinical and ophthalmologic evaluation in individuals with hearing loss. Our observations also emphasize the need for programs directed towards the prevention of hearing loss, including primary prevention as well as early diagnosis, investigation of possible genetic causes, and rehabilitation of deaf individuals.

Adolescent↗
PubMed1992

Coexistence of human T-lymphotropic virus types I and II among the Wayuu Indians from the Guajira Region of Colombia.

High prevalences of human T-lymphotropic virus type II (HTLV-II) infection have been found recently among certain Amerindian groups in North, Central, and South America. To determine if the Amerindians of Colombia are similarly affected, 523 sera, collected between 1987 and 1990 from nine culturally distinct Indian groups from widely separated regions, were tested for IgG antibodies against HTLV-I/II using enzyme-linked immunosorbent assay (ELISA) and Western blot. In addition, 243 sera from five non-Indian (black) and mixed-Indian (mestizo) populations were studied. Of the 766 individuals tested, 44 were ELISA positive, but of these, only four were Western blot positive. Three of the individuals confirmed positive by Western blot were infected with HTLV-II and one was infected with HTLV-I, as determined by differential ELISA. All four seropositive individuals belonged to a group of 62 Wayuu Indians, giving overall HTLV-I and HTLV-II seroprevalences of 1.6% and 4.8%, respectively. The coexistence of HTLV-I and HTLV-II in this Amerindian group provides an opportunity to study the factors governing transmission of these retroviruses.

Blotting, Western↗
PubMed1991

Usher syndrome: results of a screening program in Colombia.

Otological, ophthalmological and genetic studies were performed in 46 patients with Usher syndrome, identified through a screening program in Colombia. Of them, 69.6% had Usher syndrome type I, 26.1% type II, and 4.3% type III. Thirty-three patients showed profound deafness (71.7%), while 13 (28.3%) had moderate to severe hearing loss. The ophthalmologic manifestations showed marked variability. Although the majority of the patients had serious ocular impairment before age 20, 32.6% had good central visual acuity. The prevalence of Usher syndrome in Colombia, estimated at 3.2/100,000, warrants the implementation of screening programs in schools for the deaf and for the blind. Our study confirms that Usher syndrome shows no geographic or racial variation and that the disorder has a wide variability of expression and genetic heterogeneity. The large size of the families we have detected may provide important opportunities for further genetic studies, particularly in terms of the assignment of the locus and gene mapping.

Colombia↗
PubMed1990

Actinic prurigo among the Chimila Indians in Colombia: HLA studies.

The Chimila, a Colombian Amerindian group that lives at a low altitude, have a high incidence of actinic prurigo. We present the human lymphocyte antigen (HLA) findings of 43 Chimilas with the disease and of 62 control subjects and show an association of actinic prurigo with the Cw4 antigen.

Adult↗
PubMed1989

Polymorphism of serum proteins (C3, BF, HP and TF) of six populations in Colombia.

Five hundred and eighty-five serum samples from six populations in Colombia (Baranoa, Choco, Uitoto Indians, Subachoque, Pasto and Urban Bogotan) were investigated for four genetic markers. For the HP, C3 and BF systems but not for TF there is a wide range of gene frequency variation and these differences are compared with those in the few previous studies.

Black People↗
PubMed1988

Human lymphocyte antigen in actinic prurigo.

Thirty-one patients with actinic prurigo were human lymphocyte antigen (HLA)-typed. The results showed an association of this disease with the alleles B40 and Cw3, both usually found in linkage disequilibrium in most populations. Because these two antigens are more frequent in Amerindians than in whites, it is suggested that they may partly account for the restricted ethnic distribution of this disease.

Adult↗
PubMed1988

HLA antigens in the Uitoto Indians and an urban population of Colombia.

One hundred individuals from the city of Bogota and 32 Uitoto Indians from the Colombian Amazonia were HLA-typed. The results showed that the two populations differ significantly in the frequencies of the alleles A28, B15, B39, Bw51, Cw2, Cw3 and DRw52. In general, the Uitoto Indians resemble, in their histocompatibility antigens, other Latin-American Indians so far studied.

Colombia↗
PubMed1986

C3 variants and disease.

The distribution of C3 variants in dermatitis herpetiformis, thyroid cancer, spinal muscular atrophy, multiple sclerosis and psoriasis was studied, and also the Bf phenotype distribution in thyroid cancer. In thyroid cancer there was a significant deficit of heterozygotes for the C3 locus, a possible decrease in the C3F allele frequency and a significant elevation of frequency of the BfF allele. The possible involvement of these alleles in susceptibility to thyroid cancer appears worth further examination.

Alleles↗
PubMed1984

Genetic polymorphism of glutamate-pyruvate transaminase and glyoxalase I in Colombia.

Genetic polymorphism of red cell enzymes glutamate-pyruvate transaminase (GPT) and glyoxalase I (GLO) was investigated in five villages of the Colombian Andes. The GPT1 and GLO1 gene frequencies show a considerable range, but compatible to the range of European populations. In both the systems there is slight excess of observed homozygosity suggesting that the infrastructure of the subpopulations may be influenced by inbreeding.

Alanine Transaminase↗
PubMed1980

Cord serum AFP and the immunological status of the mother: a lack of correlation.

Cord serum from 139 newborns was analysed for alpha-fetoprotein and immunoglobulin G and the results correlated with the obstetric records of the mothers. No significant correlation was found in comparing either alpha-fetoprotein or immunoglobulin G levels with the previous obstetric experiences of the mothers. A previously reported sex difference of alpha-fetoprotein levels at birth was not found in this study. These results are discussed in the light of the possible immunosuppressive effects of alpha-fetoprotein.

Birth Weight↗
PubMed1979

C3 polymorphism in some Indian populations.

The distribution of C'3 phenotypes was studied in one tribal and three urban populations from India. The C'3F gene was found low in frequency compared to European and West Asian populations. Quantitatively also, the concentration of the C3 component in the Indian region was found significantly low to the European and West Asian populations reported previously.

Asia, Western↗
PubMedDate not supplied

Genetic and environmental influences on serum levels of human C4.

In a family study, levels of the C4 component of complement measured in 195 individuals show a continuous normal distribution. There is a slight but significant age effect, especially in females. Heritability is estimated at 62%. The effect of environment, however, remains substantial, and it is suggested that at some time during development the mechanism controlling the C4 levels establishes a general steady-state level whose effects remain after the divergence of sib environments with the approach of adulthood.

Adult↗
PubMedDate not supplied

Complement polymorphism in Colombia.

The polymorphism of complement component C3, BF and C4 was studied in an urban population of Bogota, Colombia and for C3 and BF, genetic heterogeneity was further examined among the five villages of the Colombian Andes. For both C3 and BF systems there is considerable variation of allele frequencies among the five villages and overall there is significant heterogeneity among the six population groups studied.

Alleles↗