Biomedical subjects

V Chavez

Publications and source records attributed to V Chavez.

6 recordsLinked to original sources

PubMed2000

Distribution of domestic triatominae and stratification of Chagas Disease transmission in Oaxaca, Mexico.

Mexico has 18 species of Triatomine bugs (Hemiptera: Reduviidae) reported to be vectors of Trypanosoma cruzi. Chagas Disease is widespread in Mexico, with up to 3.5% seropositivity of human transfusion blood. The State of Oaxaca has the longest history of endemic Chagas Disease, based on acute and chronic case reports, and of entomological surveys in the country. However, the State health care services need more information on current risks of vector transmission. In order to identify and characterize areas of transmission in Oaxaca and to stratify the vector potential, the distribution of domestic Triatominae was surveyed during 1996-98 in collaboration with the primary health care services and local communities. Villages were studied in 11% of 570 municipalities in Oaxaca. Eight triatomine species were found in domestic and peri-domestic habitats: Triatoma barberi Usinger, T. bolivari Carcavallo et al., T. dimidiata (Latreille), T. mazzottii Usinger, T. nitida Usinger, T. pallidipennis (Stal), T. phyllosoma (Burmeister) and Rhodnius prolixus Stal. For each triatomine species in Oaxaca, the range of distribution and habitat characteristics are described. Habitat partitioning, principally based on altitude and mean annual precipitation, limited the overlap of distribution between species. Relatively consistent altitude of human settlements facilitates the dispersion of individual species within microregions. Entomological indices of house infestation were used to estimate that approximately 50% of the human population (1,874,320 inhabitants) would be at risk of vector transmission, with a minimum of 134,320 infected people and 40,280 chronic cases of Chagas Disease currently in Oaxaca.

Adolescent↗

PubMed1997

Youth and violence on local television news in California.

OBJECTIVES: This study explores how local television news structures the public and policy debate on youth violence. METHODS: A content analysis was performed on 214 hours of local television news from California. Each of the 1791 stories concerning youth, violence, or both was coded and analyzed for whether it included a public health perspective. RESULTS: There were five key findings. First, violence dominated local television news coverage. Second, the specifics of particular crimes dominated coverage of violence. Third, over half of the stories on youth involved violence, while more than two thirds of the violence stories concerned youth. Fourth, episodic coverage of violence was more than five times more frequent than thematic coverage, which included links to broader social factors. Finally, only one story had an explicit public health frame. CONCLUSIONS: Local television news provides extremely limited coverage of contributing etiological factors in stories on violence. If our nation's most popular source of news continues to report on violence primarily through crime stories isolated from their social context, the chance for widespread support for public health solutions to violence will be diminished.

Adolescent↗

PubMed1996

Microsurgical anatomy of the infratentorial trabecular membranes and subarachnoid cisterns.

The understanding of the anatomy of the subarachnoid cisterns and trabecular membranes is of paramount importance in the surgical treatment of pathology of the posterior fossa. Aneurysms, arteriovenous malformations, and some tumors should be approached through the subarachnoid space. The subarachnoid cisterns provide natural pathways to approach neurovascular and cranial nerve structures. The microsurgical anatomy of the infratentorial subarachnoid cisterns was studied in twenty adult brains, using the 'immersion technique'. Air was injected into the subarachnoid cisterns and brains were dissected under the operative microscope. Six main compartmental trabecular membranes were identified in the infratentorial level. They divide the subarachnoid space into six cisterns. Cisternal divisions and the disposition of the trabecular membranes were closely related to the vascular divisional patterns of the principal arteries. Thorough knowledge of the microsurgical anatomy of the subarachnoid space will aid neurosurgeons during the surgical approach of many vascular and tumoral lesions located in the posterior fossa.

Adult↗

PubMed1996

Microsurgical anatomy of the arachnoidal trabecular membranes and cisterns at the level of the tentorium.

A clear and thorough understanding of the neuroanatomical structures of the subarachnoid cisterns is important because they provide natural pathways to intracranial arteries, veins, and nerves during microvascular procedures without disturbing surrounding important brain structures. Using a surgical microscope, we examined the microsurgical anatomy of the trabecular membranes and subarachnoid cisterns in 20 adult cadaver brains. The brains were immersed in Ringer's solution and air was injected into the subarachnoid cisterns while the brains remained submerged in solution. We identified seven trabecular membranes that limit six cisterns. We specifically looked at the anatomical relationship between the trabecular membranes and cisterns and their corresponding vessels and cranial nerves. The cistern divisions and the dispositions of trabecular membranes were closely related to the vascular division patterns of the principal brain arteries.

Adolescent↗

PubMed1994

Microsurgical anatomy of the supratentorial arachnoidal trabecular membranes and cisterns.

We examined the microsurgical anatomy of the supratentorial subarachnoid cisterns with a surgical microscope in 20 brains prepared using the immersion technique. The adult brains were immersed in Ringer's solution and air was injected into the subarachnoid cisterns while the brains remained submerged in solution. We identified nine trabecular membranes that limit the 15 cisterns. We specifically looked at the anatomical relationship between the supratentorial trabecular membranes and cisterns to their corresponding vessels and cranial nerves. The cistern divisions and the dispositions of trabecular membranes were closely related to the vascular division patterns of the principal brain arteries. A clear and thorough understanding of the neuroanatomical structures of the subarachnoid cisterns is important because they provide natural pathways to neurovascular and cranial nerve structures. These pathways allow access to intracranial arteries, veins, and nerves during microvascular procedures without disturbing surrounding important brain structures.

Adolescent↗

PubMed1992

CD23 expression in aged rats.

CD23 is considered as an activation marker. Its expression on lymphocytes was studied during aging by using 1- to 142-week-old rats. Before analysis, all animals were injected with monoclonal IgE, in order to detect their full expression of CD23 molecules on their lymphocyte surface membranes. In elderly rats, a decrease was observed in the percentages of CD23+ lymphocytes from mesenteric lymph nodes, spleen, Peyer's patches and peripheral blood. In addition, these lymphocytes expressed significantly fewer CD23 molecules per cell. Almost all CD23+ cells belonged to the B lineage and were bearing both IgM and IgD on their membranes. It is suggested that a decrease in the number of both IgM+IgD+CD23+ lymphocytes and CD23 molecules per cell may contribute to immune deficiency in the elderly.

Aging↗