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Biomedical subjects

M Tapia

Publications and source records attributed to M Tapia.

43 records · Page 3Linked to original sources
PubMedDate not supplied

Progressive latissimus dorsi muscle denervation for free-flap dynamic cardiomyoplasty.

BACKGROUND: The creation of free muscle grafts for surgical myoplasty is limited by the dependence of muscle on its original nerve supply. The aim of this study was to develop a model of gradual denervation of a large skeletal muscle (latissimus dorsi) and evaluate the possibility that atrophic degeneration and loss of function would be reduced using progressive nerve compression instead of surgical division of the nerve. The effects of chronic stimulation prior to, and after, denervation were also evaluated. METHODS: Electrodes connected to a myostimulator were implanted on 24 latissimus dorsi muscles of 12 goats. Denervation of these muscles was achieved either by sectioning of the nerve by progressive compression using ameroid rings placed around the nerve. Electrostimulation of the muscle started either 5 weeks before (prestimulation), or immediately after the denervation. RESULTS: The model of gradual nerve compression was successfully created and did have less atrophy and loss of function at mid-term when compared with nerve division. Chronic electrostimulation of the muscle after nerve division had a beneficial effect on function and on the atrophic process. Chronic electrostimulation in our model of gradual nerve compression did not mirror these beneficial results. Detrimental results were observed in groups in which chronic electrostimulation was applied prior to nerve division or constriction.

Animals↗
PubMedDate not supplied

An outbreak of hantavirus pulmonary syndrome, Chile, 1997.

An outbreak of 25 cases of Andes virus-associated hantavirus pulmonary syndrome (HPS) was recognized in southern Chile from July 1997 through January 1998. In addition to the HPS patients, three persons with mild hantaviral disease and one person with asymptomatic acute infection were identified. Epidemiologic studies suggested person-to-person transmission in two of three family clusters. Ecologic studies showed very high densities of several species of sigmodontine rodents in the area.

Adult↗
PubMedDate not supplied

[Human brain activity in response to emotional visual stimuli: open issues and recent data].

INTRODUCTION: The traditional circumplex model on the structure of emotion postulates that this process is organized in two basic dimensions: valence (positive negative) and activation (relaxing activating). This model assumes that the valence activates a single evaluative system. With regard to cerebral activity, two ideas are derived from this assumption: 1) a single set of mechanisms and neural circuits becomes activated in response to both positive and negative events, 2) the faculty of response to adverse and pleasant responses (i.e., latency and intensity with which the neural structures involved can respond) is potentially balanced. DEVELOPMENT: We describe the debates on these two issues and, subsequently, the current data regarding them are also described. These data indicate that, in response to aversive stimuli (often noxious), neural systems characterized by their ability to produce an immediate response are preferentially activated. On the other hand, pleasant stimuli (which lead to an approaching behavior towards the stimulus) preferentially activate systems associated with more intense and precise information processing. This is a slower but longer lasting type of activity. CONCLUSION: The data suggest that there are separate mechanisms for the evaluation and preparation of a response according to whether the stimulus is negative or positive.

Affect↗
PubMedDate not supplied

[Retrospective study of 50 ileostomies at the Salvador Zubirán National Institute of Nutrition].

OBJECTIVES: To establish the diseases that motivated an ileostomy and the short and long-term morbi-mortality of the procedure. METHODS: Retrospective analysis of 50 consecutive cases of ileostomies performed from 1989-1993 at a referral center in Mexico City. RESULTS: Most ileostomies were temporary (92%); the most frequent diagnoses were multiple familial polyposis, inflammatory bowel disease, and diverse intra-abdominal inflammatory complications. Operative mortality was 22%, caused mainly by the severity of the disease that motivated the ileostomy. A reoperation was required in 14% of the cases because of stomal complications (stricture, prolapse); 6% presented peristomal dermatitis, 4% high output, and 4% associated depression. With a mean time interval of three months, 32 patients were subjected to intestinal reconnection with a morbidity of 19% but no mortality. CONCLUSIONS: Ileostomy remains a necessary procedure mainly on a temporary basis. It is convenient to prevent complications by means of adequate surgical techniques, and a better rehabilitation by a multidisciplinary team.

Adult↗