Transmission electron microscopy findings in the respiratory epithelium of guinea pigs exposed to the polluted air of southwest Mexico City.

We evaluated the nature and the extent of the damage to the respiratory epithelium of guinea pigs after a 4-month exposure to the mixture of air pollutants in southwest Mexico City. Guinea pigs were placed outdoors on the roof of our facility, 8 hours daily, from February to May 1995. At the same time, control guinea pigs were kept indoors breathing filtered air. Air pollutants, temperature, and humidity data were obtained from the nearest station of the Environmental Monitoring Net. The airways and lung parenchyma were analyzed after 120 days using transmission electron microscopy (TEM). During the 4-month exposure period, ozone (O3) exceeded the norm during 511 hours, and suspended particles less than 10 microm in diameter (PM10) during 52 hours. Both pollutants reached peak levels of more than twice the norm. TEM revealed no important abnormalities in the control group. In the exposed group, there was loss of cilia, detachment of epithelial cells, and eosinophil and macrophage migration toward alveolar spaces through type I pneumocytes with destruction of their basal membranes. In six guinea pigs in the exposed group, we noted bacteria along the airways, with associated inflammatory response. We explain the colonization of the respiratory epithelium by bacteria as the result of the impairment on the defense mechanism caused by the exposure to environmental O3 and PM10.

[Bacterial vaginosis. Relation between the vaginal flora and the vaginal epithelial cells under different treatments. Ultrastructural study]. / Vaginosis bacteriana. Relación de la flora vaginal con las células epiteliales de vagina, con diferente tratamiento. Estudio ultraestructural.

At this study we analyzed morphologic relation with vaginal ephitelium, in women with bacterial vaginosis, in pre-treatment; first post-treatment and second post-treatment using metronidazol (oral), and clindamycine (intra-vaginally). From 20 patients with bacterial vaginosis, 10 received oral metronidazol, 500 mg/b.i.d. during seven days; the other patients received, clindamycine 2% intravaginal, once a day, during seven days. Couples received metronidazol. In pre-treatment, cellular prolongations produced greater adhesion of bacteria, and rests of cellular unions with adhered bacteria. There was penetration of some bacteria to epithelial cells, confirming this with serial cuts and discarding superposition in the cells. This penetration was found in five cases y persisted during the first and second post-treatment. In the first post-treatment, cellular groups without bacteria, were found. The presence of lactobacillus was low, increasing afterwards. The presence of yeasts was in the first post-treatment, and in some cases persisted. It is important to differentiate intracellular bacteria and to know the related characteristics with bacterial penetration, for an adequate prescription and a better use of medication, avoiding possible damage. The presence of bacteria may be one of the causes for bacterial vaginosis reincidence.

[Ultrastructure of the tracheal epithelium in preterm neonates treated with mechanical ventilation]. / Ultraestructura del epitelio traqueal en recién nacidos pretérmino sometidos a ventilación mecánica.

Tracheal epithelial damage, was evaluated in prematures that where intubated and with mechanical ventilation; biopsies were taken in seven preterm neonates; weight was 1100 to 2350; five were by cesarean section, y one via vaginal. Bronchial culture was negative in five, in one Lysteria monocitogena, and in another one Pseudomonas spiralis; biopsy was taken at different times o intubation. Five died because of pneumonia associated to other diseases. In optical and ultrastructural study it was found that with one day of intubation there was cilia loss; with three days of ventilation there was ciliary cells loss, and not ciliary cellular death and there were no cellular unions. In one case with three days of ventilation and 17 days of post-extubation with infection by Pseudomonas, ulcerated zones and edema were found. At 14 days there necrosis zones, increase in collagene. At 17 days there were ulcerated zones to the muscular layer with fibrosis and cellular rests at tracheal path. So, mechanical ventilation and the presence of a catheter, damage bronchial epithelium since the first 24 hours.

[Comparative study of the placenta from HIV+ mothers. Ultrastructural analysis]. / Estudio comparativo de la placenta de madres seropositivas a VIH. Análisis ultraestructural.

Perinatal vertical transmission has increased in all the world; it is considered that at the present time there are about one million of children with HIV. Variation goes from 12 to 40%, at different countries. During the last years antiretroviral drugs as AZT, ddI and others have been used to diminish the virus passage via transplacentary. Eighteen placentaes from HIV seropositive women, three corresponded to first trimester, and 15 to the third trimester of gestation; in four cases they were treated with AZT in weeks fourteen (two patients), 26 and 35 of gestation; and one patient received AZT and ddI at week 28. Control group was with ten normal placentaes. Ultraestructural analysis and immuno-peroxidase and immuno-oro with antibody anti gp 41, were done. Ultraestructurally there were different localizations of HIV virus, at sincitiotrophoblast, decidual cells and umbilical vessels (six cases). In 13 cases there was hyperplasia and hypertrophy of macrophages containing a great amount of lysosomes. In one case, where a girl was seropositive many viriones HIV, were identified in macrophages. With immuno-oro viral proteins were seen in cytoplasm an plasmatic membrane, in endothelium of fetal capillars and trophoblast. With immunoperoxidase, four cases were positive. Placentaes with antiretroviral treatment since week 14, trophoblast was more dense by philaments increment. Placentaes with treatment during the third trimester, showed normal morphology with slight increase of philaments. In the cases treated with AZT and ddI, there were not macrophages hyperplasia and hypertrophy, nor viral particles. It is concluded that in seropositive mothers without treatment, the virus may be present in any part of chorionic villi, and in patients with treatment, virus is not identified, but a viral proteins synthesis.

[Ultrastructural and immunocytochemical analysis of the synaptonemal complex at the initiation of synapsis]. / Análisis ultraestructural e immunocitoquímico del complejo sinaptonémico al inicio de la sinapsis.

The synaptonemal complexes (SCs) are nuclear structures specific for meiosis. They have a central role in homolog chromosomes coupling; they are essential in crossing over events and chromosomic segregation during the first meiotic division. When its joining ends in pakiteno stage, each synaptonemal extends along the bivalent joining the ends to nuclear wrapping. The SCs are characterized by the presence of two lateral elements and a central region. The lateral elements are parallel and equidistant. The chromatine of homolog chromosomes fixes in a series of loops to these elements. The central region is between the lateral elements. It is formed by the latero-medial fibers and the medial element. The first ones are perpendicularly oriented to the longitudinal axis of CS and connect lateral elements with the medial element. The recombination modules have an active role in recombination processes and quiasma formation, they are associated, at intervals, with the central region among the homolog chromosomes. The localization and function of nucleic acids in formation and coupling of synaptonemal complex is little known, so methodologic alternatives are looked for to resolve this type of problems. In this work, ADN distribution in chicken ovocytes in cigotene, using techniques for electronic microscopy of immuno-oro, were studied. Besides, cytochemical techniques, were used as preferential contrast for ADN or preferential for ribonucleoproteins (RNPs). The combination of preferential tincture for RNPs and immunolocalization of ADN show that chromatin accumulates jointly with ribonucleoproteins in nor coupled lateral elements and the presence of numerous RNPs fibers distributed around lateral elements. Recombination nodules were found among lateral elements during the coupling, these nodules are PTA positives, which means ADN presence, and so, ADN presence among lateral elements. THe presence of a bridge of marked fibers with coloidal gold (ADN) uniting not coupled lateral elements, suggests ADN as a sort of macromollecule forming synapsis sites.

[Gardnerella vaginalis infection in heterosexual couples. Ultrastructural study of desquamation cells of the stratified epithelium]. / Infección por Gardnerella vaginalis en parejas heterosexuales. Estudio ultraestructural en células de descamación del epitelio estratificado.

Bacterial vaginosis is one of the most frequent infections during the woman's reproductive age. Lactobacilli normal flora is substituted by relatively elevated Gardnerella vaginalis (GV), anaerobic bacteroids, Mobiluncus and Mycoplasma. The purpose of this study is to perform a morphological analysis of possible mechanisms for adhesion and penetration of GV in the heterosexual couple, in squamous epithelium at vaginal wall, as well as in seminal fluid. Ten couples with positive GV culture with three to four days of abstinence, were studied. The women presented with at least three of the four Amsel's criteria. Samples were obtained from vaginal lateral walls and from seminal fluid; these were divided in two parts: 1. To realize cultures for GV. Ureaplasma urealyticum and Mycoplasma hominis; and 2. For an ultrastructural analysis. Samples were processed with common techniques for electronic microscopy. In vaginal cells, bacteria similar to GV free form fixed to plasmatic membrane and inside the cellular cytoplasm. In the seminal fluid there were found numerous urethral cells of desquamation, which presented, as well as in woman, free form bacteria, fixed to plasmatic membrane and inside the cytoplasm. In four cases, bacteria similar to Mycoplasma, were found; and one case with particles suggesting cytomegalovirus. It is concluded in this study that: 1. The male presents with urethral cells similar to vaginal "guide cells". 2. GV colonizes urethral epithelium in the male. 3. Male is capable of infecting and/or re-infecting the woman.