Drowning in Jalisco: 1983-1989]

The objective of this work was to identify which preventive factors are involved in drowning. Files of 895 autopsies from 1983 through 1989 by the coroner site office were reviewed. During this seven year period, the annual mortality for drowning was 2.6 per 100,000 population. Males had a higher annual mortality rate (4.2 per 100,000) than females (1.1 per 100,000). The age group between one and four years old had the highest mortality rate (7.6 per 100,000). Deaths tend to cluster around summer. Most of the deaths occurred in house cisterns (19.3%), dams/lakes (16.9%), rivers/canals (14.3%), water wells (12.5%) and swimming pools (10.1%). A third of the deaths occurred at home. The relationship alcohol-drowning starts to stand out in the age group between 10 and 14 years old but get its highest percentage in the age group 35-39 (74%). There are two important findings that is necessary to point out: drowning occurring at home and the relationship between drowning and alcohol ingestion.     

Structure and function of the long terminal repeat of the chimpanzee foamy virus isolates (SFV-6)

Summary The complete long terminal repeat (LTR) nucleotide sequence of the chimpanzee foamy virus isolate SFV-6 was determined. Its 1761-bp size makes it the longest LTR reported to date among all retroviruses. Since the length of its LTR is similar to that of other simian isolates while its sequence homology is closer to that of HFV, SFV-6 genetic structure appears to be intermediate between simian and human foamy viruses. Transient expression assays demonstrate that SFV-6 encodes a transactivator of viral gene expression directed either by its own LTR or by heterologous promotors like HFV and HIV-1 LTRs. Our data also provide evidence for cross-transactivation between SFV-6 and HFV.     

Smooth muscle differentiation in cultured human breast gland stromal cells

We analyzed in cultures from the human breast the potential of stromal cells resembling fibroblasts to undergo smooth muscle differentiation. The cellular components of the breast tissue from 10 biopsies were disaggregated by collagenase digestion and further purified by differential centrifugation into suspensions of single cells and intact blood vessels. These two fractions of stromal cells were plated in culture and their phenotypic traits analyzed within 24 hours. During this time, the blood vessel fraction gave rise to stromal cells with smooth muscle differentiation as judged immunocytochemically using monoclonal antibodies to alpha-/gamma-muscle actins, to alpha-smooth muscle actin, to type IV collagen, and to laminin. Furthermore, the cells of this fraction resembled smooth muscle cells based on 2D gel electrophoresis and immunoblotting determination of isoactin content. After 24 hours in culture, the single-cell fraction consisted of an almost pure population of cells not exhibiting smooth muscle differentiation but rather resembling fibroblasts. Maintenance of fibroblast-like cells without smooth muscle differentiation was possible for more than 14 days on chemically defined medium. These cells remained quiescent, as measured by cell quantification and immunoreactivity to the proliferation-associated antigen, Ki-67. Growth of these cells could be stimulated by adding serum at any time during the experimental period. Single-cell fractions from seven biopsies were allowed to grow exponentially in the presence of serum for up to 10 days, and the kinetics of smooth muscle differentiation were monitored immunocytochemically and biochemically. These experiments showed that alpha-smooth muscle actin synthesis was induced in 10 to 80% of the fibroblast-like cells after 4 to 11 days in culture. Both the final number of alpha-smooth muscle actin-positive cells and the onset of synthesis varied with the initial seeding density. Dose-response experiments (at constant cell density) revealed that serum exerted maximal effect at concentrations above 10%. It was therefore concluded that elements of smooth muscle differentiation may arise in non-smooth muscle stromal cells taken directly from human breast tissue.     

NCAM in developing mouse gonads and ducts

Summary The expression of theNeuralCell AdhesionMolecule, NCAM, in mouse gonads and ducts was studied from fetal life to maturity. The methods used were immunocytochemical staining and Western blotting. The immunocytochemical studies showed that the only structures that remain NCAM-positive throughout life were the mesonephric-derived rete ovarii and rete testis. Also in the fetal gonads some somatic cell lining the groups of differentiating germ cells were stained. In the immature as well as in the mature ovary the granulosa cells and oocytes of growing and large follicles — but not of small follicles — were stained. A particularly strong staining of the cytoplasm of the oocyte, healthy as well as atretic, was seen. All cells of the testis remained negative except for weakly stained residual bodies and late spermatids. At all ages the male ducts showed only weak staining, whereas in the female Müllerian duct the epithelium became strongly positive at puberty. The stroma of the Müllerian duct was positive during a transitory period around day 16 of fetal life in both sexes. One-dimensional gel immunoblotting of total protein from gonads, rete and ducts from immature and mature mice showed that only the two largest isoforms of NCAM (NCAM-A and NCAM-B) were present. The gonads and the rete of both sexes and the adult uterus expressed only NCAM-B, whereas NCAM-A was also detected in the adult epididymis. The present findings suggest that NCAM may be involved in the normal development and formation of both the gonads and ducts. In particular, NCAM may play a part in sustaining the integrity of the rete testis, thus ensuring the pathway for spermatozoa from the testis to the epididymis. Furthermore this cell adhesion molecule may also be important for follicular growth and differentiation.     

Antigen-independent acquisition of MHC class II molecules by human T lymphocytes

We report here that human T lymphocytes have the capacity of acquiring large amounts of MHC class II molecules from various types of antigen-presenting cells (APC) in an antigen-independent manner. The transfer of MHC class II molecules from APC to T cell required direct cell-to-cell contact and appeared to involve the interaction of numerous adhesion molecules between these cells. Depletion of cholesterol from the plasma membrane reduced the amount of MHC class II transferred onto the T cells. Most significantly, the newly acquired MHC class II molecules were capable of efficiently presenting antigen to T helper cells. These results suggest that T cells are able to interact with other T cells to regulate immune responses by presenting MHC peptide complexes that have been snatched away from nearby APC.     

The stimulatory effect of α‐melanotropin on progesterone release from rat granulosa cells is inhibited by interleukin‐1β and by tumour necrosis factor‐α

Aim: Several studies have shown that a variety of peptides and cytokines are involved in ovarian regulatory mechanisms; however, their exact function is still unclear. In this work we study whether the administration of peptide α‐melanotropin and the cytokines interleukin‐1β (IL‐1β) and tumour necrosis factor‐α (TNF‐α) on their own modify the release of progesterone in cultured granulosa cells (GC) from pro‐oestrous rats. We also investigate an interaction between these cytokines and α‐melanotropin in the modulation of progesterone secretion. Methods: Granulosa cells were collected from the ovaries of female Wistar rats and cultured for up to 24 h in the presence of different concentrations of α‐melanotropin, cytokines or a combination of both. Progesterone concentration was measured by radioimmunoassay. Results: The addition of α‐melanotropin in a dose of 0.01 and 0.1 mm had no effect on progesterone release, whereas a dose of 1 mm significantly increased progesterone release (P < 0.01) compared with the control culture. Progesterone release was not modified when different concentrations of interleukin‐1β or TNF‐α were added to the cell cultures. However, when interleukin‐1β or TNF‐α were added simultaneously with 1 μm α‐melanotropin, a significant reduction (P < 0.01 for interleukin‐1β and P < 0.05 for TNF‐α) of the steroid release was found with respect to the α‐melanotropin‐treated group. Conclusions: These results lead us to suggest that, although α‐melanotropin stimulates progesterone release in pre‐ovulatory GC, this effect is blocked by the presence of interleukin‐1β or TNF‐α.     

Lymphangioma of the spermatic cord

We report a new case of spermatic cord lymphangioma in a infant 2 years old. The initial diagnosis was funicular hydrocele. The treatment was the local excision of tumor and the diagnostic was histological. Postoperative course was excellent. Must be explored the transillumination of the mass which would have led us to think other the diagnosis different from that of the cord hydrocele before the operation since it would have given negative. During the operation, must the assured that the cystic anomaly is limited to spermatic cord, to evite recurrences in the postoperative course.     

Identification and characterization of a T-helper peptide from carcinoembryonic antigen.

PURPOSE: The purpose of this research was to identify promiscuous T-helper cell determinants (THd) from carcinoembryonic antigen (CEA) to be used to prime T-cell help for cancer therapy. CEA was selected because this antigen is expressed in an important variety of carcinomas. EXPERIMENTAL DESIGN: Potential promiscuous THd from CEA were predicted using available computer algorithms. Predicted peptides were synthesized and tested in binding experiments to different HLA-DR molecules. Binder peptides were then used to prime T-cell responses both in vitro and in vivo. RESULTS: Twenty 15-mer peptides from CEA were predicted to bind to different HLA-DR molecules. The promiscuous character of these peptides was demonstrated in binding experiments. Fifteen of 20 peptides tested were able to bind to HLA-DR4, but only CEA (625-639) was shown to be presented after processing of recombinant CEA. CEA (625-639) was also found to be presented by HLA-DR53. Moreover, immunization of HLA-DR4 transgenic mice with CEA (625-639) in conjunction with class I epitope OVA (257-264), induced a CTL response specific of OVA (257-264). CONCLUSIONS: CEA (625-639) might be a relevant promiscuous THd peptide for cancer therapy.