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Biomedical subjects

L Cifuentes

Publications and source records attributed to L Cifuentes.

At least 55 records · Page 3Linked to original sources
PubMed1993

[MN blood group and congenital malformations].

This work analyzes the mother-son segregation of MN blood group in malformed and normal newborns. MN blood group was measured in 90 malformed, 70 paired normal newborns and their respective mothers, at the Maternity of the University of Chile Clinical Hospital. The expected values for the different mother-child pairs were calculated according to the ITO matrix method, using maximally probable appraisers. Among malformed newborns, there was an excess of heterozygous sons when the mother was homozygous for the MN system. Among malformed males, there was an excess of MM-MN and MN-MM mother-son pairs. Among control newborns, no distortions were found. These results suggest that there is a strong association between MN heterozygosis, sex and congenital malformations.

Congenital Abnormalities↗
PubMed1992

[Cleft lip and cleft palate: cephalometric characteristics of affected individuals, their relatives and a control population].

Eight cephalometric parameters were determined in individuals affected with cleft lip and cleft palate, their parents and siblings and a sample of normal individuals. No differences were found in males in any group. In contrast, affected females had lower measurements than their female relatives, and these lower latter in turn had measurements than control females. Although differences between groups were significant enough overlap existed and therefore genetic counseling based on these measurements would be uncertain.

Adolescent↗
PubMed1992

[Familial association of epilepsy and cleft palate: an expression of predisposed common genetic factors or a teratogenic effect of the epilepsy genotype?].

The familial association of epilepsy and cleft lip with or without cleft palate (CL (P)) is analyzed assuming both entities share common genetic predisposing factors. The genealogical data stemming from 169 CL (P) probands and 168 epileptic probands yielded information on the prevalence rates of cleft and epileptic relatives. The working hypothesis assumes that the relatives of epileptic and cleft probands should have a greater liability to CL (P) and epilepsy, respectively. The results obtained do not support the hypothesis of an etiologic association given that a greater joint prevalence of epileptic and cleft relatives is only observed when the proband is epileptic and not with a cleft proband. This situation seems to reflect a teratogenic effect of the epileptic genotype which expresses itself in those individuals which simultaneously present a greater liability to cleft.

Cleft Lip↗
PubMed1992

[Paternity study in Chilean families using DNA fingerprints and erythrocyte blood markers].

In the last decade, the electromorphic phenotype corresponding to extremely polymorphic zones of DNA, that include variable number of tandem repeat loci (VNTR) of oligonucleotide sequences, have been added to classical markers to elucidate the problems of parenthood identification and ascription in human beings. Using VNTR of several loci, a band profile practically unique for each individual is obtained (DNA-fingerprints). Since the pattern of VNTR electrophoretic bands is inherited from parents in a proportion of 50% from each one, this system is extremely useful for paternity ascription or exclusion. Nine nuclear families were studied, randomly selected from a group of 170 families that were analyzed using 5 erythrocyte genetic markers and with VNTRs detected using the multi locus probe (CAC)5, aiming to explore the concordance of both methods. Results were similar for both methods; however for VNTR, there is no information available on population frequency of polymorphisms.

Blood Group Antigens↗
PubMed1992

[Epidemiologic study of factors associated with hypospadias].

From August 60 to December 90, 103 male newborns with hypospadias were diagnosed among 124 588 consecutive newborns examined (8.3 per 10,000). Mortality among them was 1.94%. The annual incidence rate increased significantly over the study period (p < 0.001. Hypospadias was an isolated finding in 92% of cases, and its was associated to other non genital malformation in 8.7%. Location of hypospadias was distal in 73% and proximal in 15.5%. There was no seasonal variation in the incidence rate. Weight of affected individuals did not differ from that of controls. Older age of parents among affected individuals was not statistically significant.

Abnormalities, Multiple↗
PubMed1991

Quantitative analysis of genetic differentiation among European and Chilean strains of Drosophila subobscura.

An analysis of the interpopulational differences observed between four European and four Chilean stocks of Drosophila subobscura, with regard to wing size, egg-to-adult development time and preadult viability, shows highly significant differences between the eight stocks irrespective of the continent from which the flies are derived. The divergence of the local populations with regard to the quantitative traits described here, supplements other evidence of interpopulational differences in mating activity, chromosomal and enzyme polymorphisms. These together indicate that the evolutionary process that promotes race formation is relatively rapid, bearing in mind that D. subobscura was detected for the first time in South America in 1978.

Animals↗
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↗
PubMed1991

[Increase of incidence of Down syndrome and its possible relation with increased maternal age].

Among 47,458 consecutive births taking place between july 1977 and december 1989, we found 83 newborns with Down syndrome, for a 1.74/1000 live births incidence rate. This compares to a rate of 1.39 rate observed at the same maternity from 1971 to 1977 (NS). The mean age of all mothers was 25.9 years as compared to 31.87 for mothers of children with Down syndrome (p < 0.00001). The mean maternal age has increased from 24.34 in 1977 to 27.38 in 1988 (p < 0.0001), mostly due to a greater proportion of the 25 to 29 year-old group of mothers. These data support, although not conclusively, that the increased incidence of Down syndrome in our population is related to older maternal age.

Adolescent↗
PubMed1990

[Incidence of malformations of the central nervous system: 1978-1988].

During the period Jan 1978 to Dec 1988, 41,867 deliveries took place at the University of Chile Hospital. Among them, 148 babies were found to have malformations of the central nervous system, an incidence of 3.6 per 1000 live births. A longitudinal study from 1969 to 1988 suggests a yearly increment of 0.1% in the incidence rate of these malformations. The comparison of some quantitative variables, such as gestational age, birthweight, number of previous abortions and some risk factors like maternal illness, bleeding, radiation exposure, drug ingestion during the first trimester of pregnancy and instructional level of both parents show significant differences between the malformed and the control newborns. No significant differences were found for maternal age, sex nor seasonal variation.

Abnormalities, Drug-Induced↗
PubMed1989

[Incidence of congenital malformations in Chile from 1969 to 1986. Results of a Latin-American collaborative study].

At present, congenital malformations contribute more to infant mortality, given the significant decrease in overall infant mortality rate observed in Chile. A significant and steady increase in the prevalence of congenital malformations was demonstrated at the Clinical Hospital, University of Chile, from 1969 to 1986. Better epidemiologic surveillance is needed to accurately estimate the magnitude of this problem and give orientation for preventive measures.

Chile↗
PubMed1989

[Congenital malformations: a model predictive based on risk factors].

Several risk factors were studied in regard to congenital malformations. Malformed newborns (n = 1200) and controls (n = 1200) seen at the Universidad de Chile Hospital between 1969 and 1979 were examined. Their mothers were asked about possible risk factors. Parenteral age and birth order was significantly higher for malformed newborns than for controls. A family history of congenital malformations was more frequent in malformed newborns. Infertility, metrorrhagia and maternal diseases during pregnancy were more frequent in malformed newborns than in controls. A function that discriminates between controls mothers and mothers of malformed newborns was obtained by a logistic regression model. This function correctly predicted 65% of cases.

Congenital Abnormalities↗
PubMed1979

Microenvironmental arginine depletion by macrophages in vivo.

Since the tumour-selective cytotoxic activity of activated macrophages in vitro can be attributed to depletion of the culture medium of L-arginine by macrophage arginase, a series of experiments was designed to determine whether such a mechanism could operate in vivo. Extracellular fluid obtained from Gullino chambers within established tumours contained high levels of arginase, no detectable arginine and high levels of ornithine. When tumours were disaggregated into single-cell suspensions, arginase was readily detected within tumour macrophages but not within malignant cells. Inflammatory ascites induced in mice by Corynebacterium parvum was rich in arginase, depleted of L-arginine and cytotoxic in vitro to L5178Y and V79 cells. High levels of arginase in the ascites fluid were associated with resistance to challenge with syngeneic L5178Y cells. Lymph collected from the cisterna chyli in rats bearing a macrophage-rich sarcoma on the small bowel contained elevated levels of arginase, was depleted of arginine and contained increased concentrations of ornithine. We conclude that in sites of macrophage infiltration there is microenvironmental arginine depletion due to the action of arginase, and that arginase release could represent an important macrophage effector mechanism against a variety of targets, including malignant cells, virus-infected cells, fungi and parasites.

Animals↗