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Biomedical subjects

R J Oliveira

Publications and source records attributed to R J Oliveira.

7 recordsLinked to original sources
PubMed2005

Developmental exposure to fenproporex: reproductive and morphological evaluation.

This study was designed to evaluate the maternal toxicity and teratogenicity of fenproporex, one of the most widely-used anorectic drugs in many countries, including Brazil. Three periods of exposure were evaluated: (a) 30 days before mating; (b) from gestational day (GD) 0 to 14; and (c) 30 days before mating and during pregnancy, until GD 14. Female mice from experimental groups received, by gavage, 15 mg/kg of fenproporex. Treatment with fenproporex increased ambulation of dams in the open-field test and did not influence the mobility in the forced-swimming test. There was no significant difference in maternal weight gain between the controls and fenproporex-treated groups, although fenproporex treatment reduced the gravid uterus weight. No significant difference was observed in postimplantation loss, fetal viability and sex ratio. In addition, this compound did not impair intra-uterine growth. The reduction in the number of implantations in the groups receiving fenproporex indicates that this drug may have an adverse effect on implantation. Fenproporex treatment also increased the number of fetuses presenting small kidneys and cervical ribs. The present results indicate that fenproporex, in the dose and exposure periods tested, appears to exhibit a low maternal toxicity and teratogenic potential in mice.

Amphetamines↗
PubMed1997

The active earcanal.

In the past, the human earcanal has primarily been thought of as a passive conduit for sound. Several studies, reported here, explored evidence of how active the earcanal is. The "active earcanal" is conceptualized and aspects of it are viewed through three timeframes: jaw-induced canal change in seconds/minutes, cerumen production in weeks/months, and aging in years. The influence of each of these aspects on hearing aid performance and resulting patient satisfaction is explored. A new self-assessment tool, a Profile of Hearing Aid Physical Fit, is proposed that focuses on measuring patients' perceptions of those benefits that depend on the interface between earcanal and hearing aid.

Aged↗
PubMed1996

Migration of vesicular stomatitis virus glycoprotein to the nucleus of infected cells.

A new means of direct visualization of the early events of viral infection by selective fluorescence labeling of viral proteins coupled with digital imaging microscopy is reported. The early phases of viral infection have great importance for understanding viral replication and pathogenesis. Vesicular stomatitis virus, the best-studied rhabdovirus, is composed of an RNA genome of negative sense, five viral proteins, and membrane lipids derived from the host cell. The glycoprotein of vesicular stomatitis virus was labeled with fluorescein isothiocyanate, and the labeled virus was incubated with baby hamster kidney cells. After initiation of infection, the fluorescence of the labeled glycoprotein was first seen inside the cells in endocytic vesicles. The fluorescence progressively migrated to the nucleus of infected cells. After 1 h of infection, the virus glycoprotein was concentrated in the nucleus and could be recovered intact in a preparation of purified nuclei. These results suggest that uncoating of the viral RNA occurs close to the nuclear membrane, which would precede transcription of the leader RNA that enters the nucleus to shut off cellular RNA synthesis and DNA replication.

Animals↗
PubMed1992

A look at ear canal changes with jaw motion.

Two procedures were used with one subject to examine changes in the ear canal with jaw motion. Silicone ear impressions were examined to measure the effect of jaw position. Magnetic resonance imaging was used to define the three-dimensional structure of the canal and visualize key underlying tissue. Results showed that inexpensive impressions can detail changes in the cartilaginous region of the canal. Approximately a 25% change in this subject's ear canal with different jaw positions was observed in the anterior/posterior plane with essentially no change in the superior/inferior plane. This is likely related to asymmetric stress from action of the mandibular condyle on neighboring cartilaginous tissue. Solutions to jaw motion-induced feedback problems are suggested.

Ear Canal↗