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Biomedical subjects

J M Vargas

Publications and source records attributed to J M Vargas.

6 recordsLinked to original sources
PubMed2006

Short term oral minocycline treatment of meibomianitis.

AIM: To evaluate the clinical impact, aqueous tear parameters, and meibomian gland morphology in patients with primary meibomianitis before, during, and 3 months after a course of oral minocycline. METHODS: 16 patients were prospectively enrolled, 11 male and five female (mean age 69 years old). Each patient received routine clinical evaluations before, after 3 months therapy, and at 6 month study follow up visit. The clinical appearance, tear volume, flow and turnover, evaporation, Schirmer I test, meibomian gland dropout, lissamine green staining, and bacteriology wer evaluated. RESULTS: Improvement was observed in clinical signs of meibomianitis at the second and third visits. Microbial culture findings improved. Decreased aqueous tear volume and flow, and increased evaporation rate range at 35-45% relative humidity (RH) (p < 0.05) were also detected. Other related tear parameters did not change. Meibomian gland dropout showed no improvement. CONCLUSIONS: 3 months of oral minocycline resulted in clinical improvements in all meibomianitis signs that persisted for at least 3 months after discontinuation despite decreased aqueous tear volume and flow with increased evaporation (35-45% RH). However, there was improvement in the turbidity of secretions. Short term minocycline therapy probably has efficacy in the management of meibomianitis that extends beyond eradication of bacteria.

Administration, Oral↗
PubMed1999

Symmetry breaking and adaptation: evidence from a 'toy model' of a virus.

We argue that an induced breaking of the genetic synonym symmetry due to the action of genetic operators such as mutation can enhance the adaptability of a species to changes in the environment. In the case of a virus, the claim is that the codon bias in the neutralization epitope improves the virus' ability to generate mutants that evade the induced immune response. We support our claim with a simple 'toy model' of a viral epitope evolving in competition with the immune system. The effective selective advantage of a higher mutability leads to a dominance of codons that favor non-synonymous mutations. As further evidence we present a simple model for a genetic regulatory network that leads to adaptive evolution in a population of giraffes by means of an induced symmetry breaking rather than through any direct selective advantage.

Adaptation, Physiological↗
PubMed1990

[Surgery for infectious endocarditis].

OBJECTIVE: to assess the experience of both departments in the surgical therapy of infective endocarditis--indications and results. DESIGN: retrospective analysis on clinical data, surgery and follow up. SETTING: patients (pts) studied in the Cardiology Department and Cardiothoracic Surgery Department of the Santa Marta Hospital in Lisbon. PATIENTS AND INTERVENTIONS: sequential sample of 28 patients (11 females, 17 males, mean age 39 years) submitted to surgery between 1978 and 1987 for infective endocarditis. MEASUREMENTS AND RESULTS: the indications for surgery were: heart failure (15 pts), "resistant" infection (8 pts), emboli (4 pts) and "large" vegetations shown by echocardiography (2 pts). Surgical mortality -27.5%. Four patients developed periprosthetic leaks. There was an improvement in functional class of the survivals. CONCLUSION: the indications for surgery were heart failure, "resistant" infection, emboli and "large" vegetations. There was a high surgical mortality, namely in the patients with resistant infection, severe heart failure and periprosthetic leaks. In the follow up there was a net improvement of functional class. The morbidity is due to the periprosthetic leaks, which induced most of the reoperations.

Adolescent↗