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H Villegas

Publications and source records attributed to H Villegas.

18 recordsLinked to original sources
PubMed2001

Electron microscopic studies of ion- and H2O-transporting epithelial cells in the horizontal ampulla of the pigeon.

Earlier morphological studies of the epithelial structure in the semicircular canals of mammals have focused on the sensory cells of the crista ampullaris. This report draws attention to the fact that there exist at least seven further cell types in the horizontal ampulla walls of pigeon with various functions; the role of ion- and H2O-transporting epithelial cells is dealt with here in detail. While the dark cells appear to play a decisive role in the regulation of ionic composition, the cells in the planum semilunatum may transport H2O and assist in the regulation of endolymph volume. In addition, protein-secreting structures are located in the apical region of the cells of the planum semilunatum. The question whether the proteins are dispersed in the endolymph or contribute to cupula formation remains unclear. The morphology and possible functions of these two cell types are discussed on the basis of electron microscopic results.

Animals↗
PubMed1996

[Ultrastructural analysis of placentas with villitis. Retrospective study].

A villitis is a focal or multifocal inflammatory reaction of chorionic villi with infiltration of mononuclear cells and usually is associated with fibrinoid necrosis. The aetiology of villitis could be a transplacental infection of the fetus, especially with virus (VIV), in normal placentae however, the presence of villitis is referred as villitis of unknown ethiology (VED). This study was designed to characterize villitis lesions of 11 placentae, four VIV and seven VED, ultrastructural descriptive comparisons of both types of villitis are discussed. Biopsies were processed with the conventional optic and electronic microscopy techniques. Our ultrastructural observations confirmed the presence of virus in four placentae whereas no virus or bacteria were found in seven placentae. Microvilli were absent or markedly diminished, this finding was associated to the presence of fibrinoid necrosis in the stroma and clinically to intrauterine growth retardation, 4 preterm pregnancies and one obitus. Trophoblast alterations were found in both types of villitis, basal membrane thickness, is some cases associated to electrodense material similar to calcium deposites, vascuolization and the presence of edema in the stroma was observed. In some cases we noted the presence of focal fibrin deposits associated to necrosis zones in the stroma, calcium precipitates and mielinic bodies. Fetal vessels obliteration and intravascular thrombi were found in the syncitiotrophoblast placentae with viral particles CMV or rubivirus associated to an increment in Hofbauer cells and basal membrane calcifications. From our ultrastructural observations, we conclude that both types of villitis are associated to a typic immunologic reaction that induce lose of trophoblast microvilli, mononuclear infiltration and edema. This placental alterations reduce dramatically the maternofetal exchange of gases, nutrients and other active peptides and could be the cause of fetal growth retardation, inmadurity or death.

Chorionic Villi↗
PubMed1978

[Human fetal growth in Costa Rica, 1970-1975].

Costa Rica has experienced a marked reduction in infant mortality--both in the neonatal and post-neonatal components--in the last decade. The decline could be related to improvements in the pattern of fetal growth. The present report analyses the birth weight of newborns from a random sample of all births in the Republic of Costa Rica during 1970 and 1975. While the average birth weight in that period was 3100 grams, the prevalence of low birth weight neonates decreased from 9 to 7 per cent in five years. The provinces of Limon and San Jose exhibited the highest frequency of low birth weight. Women 20 to 29 years old had babies with better or optimal body weight. Age, marital status and occupation of the mother appeared correlated with birth weight. A relationship between changes in fetal growth and changes in maternal, perinatal and neonatal mortality is apparent. The present situation of birth weight places Costa Rica among the countries in transition with a clearer perspective to attain an even higher infant survival in the near future. In this regard, several measures oriented toward prevention of low birth weight are recommended.

Adolescent↗
PubMed1977

Extension of health service coverage in Costa Rica.

Costa Rica's National Health Plan for 1971-1980 has given top priority to extension of health coverage--focusing especially on marginal rural and periurban areas. By June 1977 implementation of this plan had provided coverage for over 80 per cent of Costa Rica's scattered rural population. Community participation was being encouraged, together with an integrated approach to the problems of these marginal regions.

Community Health Services↗
PubMedDate not supplied

Electron microscopy of Chlamydia trachomatis infection of the male genital tract.

Semen specimens and testicular and epididymis biopsy from a patient of an infertile marriage were examined by transmission electron microscopy. Intraepithelial vesicles containing C. trachomatis were present in remaining cytoplasmic droplets in spermatozoa, desquamated epithelial cells, and stereocilia from epididymis. Elementary bodies were demonstrated in connective tissue from testes and in Leydig cells. The association between the microorganisms and spermatozoa contribute to the decreased motility and necrospermia. The morphologic alterations in epididymis are responsible for decreased sperm maturation. The damage to Leydig cells can be demonstrated only by electron microscopy.

Adult↗
PubMedDate not supplied

Ultrastructural characteristics of Gardnerella vaginalis infection in the heterosexual couple.

Adhesion and penetration of Gardnerella vaginalis into the male urethral and female vaginal epithelial cells were evaluated in a prospective cohort study of infected females and their sexual partners. Vaginal secretions of 10 women with culture proven G. vaginalis infection and semen samples of their asymptomatic husbands were analyzed with conventional optical and electron microscopy. G. vaginalis was isolated in 50% of the male sexual partners of women harboring the microorganism. G. vaginalis adheres to the plasmatic membrane and penetrates into the cytoplasm of both vaginal and urethral epithelial cells. The ability of G. vaginalis to colonize the male lower genital tract may have clinical relevance with respect to the role of the male partner in the reinfection of women.

Bacterial Adhesion↗
PubMedDate not supplied

[Prevalence of microscopic coronary atheroma in young adults from Mexico City].

The prevalence of microscopic atheroma in the proximal left anterior descending coronary artery was studied in thirty young males aged 20 to 29 years, living in Mexico City, who died in urban accidents. All of them were either unemployed or labor workers with a socioeconomical status considered to be representative of the majority of young males living in Mexico City. It was found that coronary atheroma was present in 11 of them (33%) with variable degrees of luminal obstruction. In two of them the luminal obstruction was greater than 75%. The prevalence found in this group was significantly different to that found in younger and older males who also died in accidents. Since the prevalence of coronary atheroma was not related to ventricular hypertrophy, valvular or congenital heart disease our findings indicate that in Mexico City as in other geographical regions, coronary atherosclerosis is not an unusual finding in males in the third decade of life, with a low socioeconomical status.

Accidents↗