Biomedical subjects

L B Oliveira

Publications and source records attributed to L B Oliveira.

8 recordsLinked to original sources

PubMed2005

GABA(A) receptor activation in the lateral parabrachial nucleus induces water and hypertonic NaCl intake.

Inhibitory serotonergic and cholecystokinergic mechanisms in the lateral parabrachial nucleus and central GABAergic mechanisms are involved in the regulation of water and NaCl intake. In the present study we investigated if the GABA(A) receptors in the lateral parabrachial nucleus are involved in the control of water, NaCl and food intake in rats. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the lateral parabrachial nucleus were used. Bilateral injections of muscimol (0.2 nmol/0.2 microl) into the lateral parabrachial nucleus strongly increased 0.3 M NaCl (20.3+/-7.2 vs. saline: 2.6+/-0.9 ml/180 min) without changing water intake induced by the treatment with the diuretic furosemide combined with low dose of the angiotensin converting enzyme inhibitor captopril s.c. In euhydrated and satiated rats, bilateral lateral parabrachial nucleus injections of muscimol (0.2 and 0.5 nmol/0.2 microl) induced 0.3 M NaCl intake (12.1+/-6.5 and 32.5+/-7.3 ml/180 min, respectively, vs. saline: 0.4+/-0.2 ml/180 min) and water intake (5.2+/-2.0 and 7.6+/-2.8 ml/180 min, respectively, vs. saline: 0.8+/-0.4 ml/180 min), but no food intake (2+/-0.4 g/240 min vs. saline: 1+/-0.3 g/240 min). Bilateral lateral parabrachial nucleus injections of the GABA(A) antagonist bicuculline (1.6 nmol/0.2 microl) abolished the effects of muscimol (0.5 nmol/0.2 microl) on 0.3 M NaCl and water intake. Muscimol (0.5 nmol/0.2 microl) into the lateral parabrachial nucleus also induced a slight ingestion of water (4.2+/-1.6 ml/240 min vs. saline: 1.1+/-0.3 ml/240 min) when only water was available, a long lasting (for at least 2 h) increase on mean arterial pressure (14+/-4 mm Hg, vs. saline: -1+/-1 mm Hg) and only a tendency to increase urinary volume and Na+ and K+ renal excretion. Therefore the activation of GABA(A) receptors in the lateral parabrachial nucleus induces strong NaCl intake, a small ingestion of water and pressor responses, without changes on food intake.

Analysis of Variance↗

PubMed2004

Energy conservation and CO2 emission reductions due to recycling in Brazil.

The present paper aims to make the energy saving potential provided by waste recycling in Brazil evident by pointing out more specifically the benefits regarding climate change mitigation. In this case, based on the energy saved due to the recycling process of an exogenous amount of waste, we have built two scenarios in order to show the potential for indirectly avoiding CO2 emissions in the country as a result of the recycling process. According to the scenario, 1 Mt and 3.5 Mt of CO2, respectively, would be avoided per year due to solid waste recycling. The international context for greenhouse gas emissions reduction, such as the United Nations Framework Convention on Climate Change and its Kyoto Protocol has been taken into account.

Air Pollutants↗

PubMed2001

Dispase facilitates posterior vitreous detachment during vitrectomy in young pigs.

PURPOSE: To evaluate the role of intravitreal dispase in conjunction with pars plana vitrectomy to facilitate the creation of a posterior vitreous detachment (PVD) in young pig eyes. METHODS: Twenty-four eyes of 24 animals were randomized to receive an intravitreal injection of dispase (50 microg/0.05 mL) or phosphate buffered saline (PBS) immediately after core vitrectomy and before attempted creation of a posterior cortical vitreous detachment. Following a 15-minute waiting period, surgical creation of a posterior vitreous separation was attempted by aspiration of the posterior vitreous immediately adjacent to the optic disk. Eyes were evaluated postoperatively by clinical examination (1, 4, and 8 weeks) and electroretinography (4 and 8 weeks), after which they were enucleated for light, scanning, and transmission electron microscopy. RESULTS: Based on intraoperative findings and postoperative scanning electron microscopy, eyes receiving intravitreal dispase exhibited a higher incidence of PVD compared to eyes receiving PBS (P = 0.029). Electroretinographic responses recorded at postoperative weeks 4 and 8 were similar in both dispase and PBS eyes compared to the unoperated fellow eyes. Clinical examinations, including indirect ophthalmoscopy, were indistinguishable between the PBS eyes and 11 of 12 eyes in the dispase group. Light and transmission electron microscopy demonstrated no differences in the retina between the dispase eyes and the PBS operated controls. CONCLUSION: Dispase is a useful adjunct in facilitating surgical creation of a PVDin young pig eyes.

Animals↗

PubMed2000

Early loss of synaptic protein PSD-95 from rod terminals of rhodopsin P347L transgenic porcine retina.

Retinitis pigmentosa (RP), a type of retinal degeneration involving first rod and then slow cone photoreceptor degeneration, can be caused by any of a number of mutations in different genes. In the cases of mutations affecting rod-specific genes such as rhodopsin, it is unclear how the mutations may cause degeneration of cones. We have used the porcine retina, which is rod-dominated and has an abundance of cones, to study the mutation-induced changes in both rod and cone photoreceptors. Like patients with the same mutation, rhodopsin P347L transgenic swine manifest rod-cone degeneration. In addition, the rod bipolar cells fail to form synaptic connections with rods; instead, they form ectopic synapses with cones. The mechanisms that prevent the formation of the rod-rod bipolar cell synaptic connection are not known. We used specific antibodies and immunocytochemistry to show that the synaptic protein, PSD-95, is present in both normal and transgenic porcine retinas. During neonatal development, however, PSD-95 is lost from rod terminals in the transgenic swine. This loss is virtually complete (90%) by postnatal day 5, at a time when greater than 80% of rod cell bodies still remain. Furthermore, the remaining rods retain their outer segments and their gross morphology appears relatively normal. In contrast, PSD-95 expression continues in cone terminals, even in 10-month-old transgenic swine, where the rods have all disappeared and the cones show signs of severe degeneration. These results suggest that loss of PSD-95 may not be a general consequence of the deteriorating cell. Rather, the very early and selective loss of PSD-95 from the rod terminals may be causally related to the absence of rod-rod bipolar cell synapses in the rhodopsin P347L transgenic retina.

Animals↗

PubMed1995

Lack of effect of oral hygiene training on periodontal disease progression over 3 years in adolescents.

A comprehensive new oral hygiene training program has lately been described and found effective in controlling dental plaque formation and in significantly reducing the incidence of approximal dental caries and gingivitis in adolescents. This study investigated the long-term effect of plaque control on the progression of periodontal diseases in adolescents. A group of 227 Brazilian schoolchildren were followed up over a period of 3 years. The children were divided randomly into 3 groups. The first group was given a needs-related intensive program which combined detailed information to parents and children pertaining to the etiology and prevention of dental diseases, instructions in self-diagnosis of plaque and gingivitis, and a detailed oral hygiene training based on individual needs, together with continued feedback and motivation during the entire 3 years. The second group was given a similar program, but through shorter sessions and with no motivation and feedback and no training in self-diagnosis. A control group received no motivation sessions or oral hygiene training. The 3 groups were examined radiographically at baseline and annually at 3 subsequent occasions. The data were analyzed with a multi-level variance analysis. The frequency of subjects showing sites with alveolar bone loss increased steadily during the entire period in all groups. Neither of the training programs had a significant effect on the alveolar bone level during 3 years compared to the control group. Generally, girls demonstrated higher proportions of approximal tooth surfaces showing radiographic bone loss, though not statistically significant. In this population the supragingival plaque control lacked any significant effect on periodontal disease progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Effect of two preventive programs on oral health knowledge and habits among Brazilian schoolchildren.

The effect upon dental health knowledge and dental health behavior of a comprehensive and a less comprehensive preventive program was compared in a 3-yr follow up study. The comprehensive program included active participation of the students and parental involvement. The study group consisted of 186 Brazilian schoolchildren 13 yr of age at the start of the program. A reference group from another school of similar socioeconomic level was included in the analyses. The data were collected from questionnaires filled in by the children under surveillance after the completion of the program. Significant differences in knowledge as well as in reported behavior were observed. The children enrolled in the comprehensive program in general scored higher in dental health knowledge than did those in the less comprehensive program. However, the latter group of children seemed to have acquired more correct knowledge during the period than had the control and reference children. Similar results were obtained concerning reported dental health behavior.

Adolescent↗

PubMedDate not supplied

In vivo effectiveness of laser fluorescence compared to visual inspection and radiography for the detection of occlusal caries in primary teeth.

The purpose of this study was to evaluate the in vivo effectiveness of laser fluorescence compared to visual inspection and radiography for the detection of occlusal caries in primary teeth. Fifty sites from 30 molars in 29 patients were selected and evaluated under standardized conditions by 2 previously trained examiners according to the 3 diagnostic methods. Histological examination served as gold standard after exfoliation or extraction. Values obtained for sensitivity, specificity and accuracy were 0.60, 0.90 and 0.73 for laser fluorescence, 0.82, 0.85 and 0.84 for visual inspection and 0.62, 0.73 and 0.67 for radiography, respectively. Considering only dentinal caries, values were 0.73, 0.95 and 0.90 for laser fluorescence, 0.61, 1.00 and 0.90 for visual inspection and 0.96, 0.81 and 0.85 for radiography, respectively. We conclude that for the detection of occlusal caries in primary molars laser fluorescence presents a similar accuracy when compared to visual inspection and radiography, although visual inspection showed better values for sensitivities for both enamel and dentin lesions.

Child↗

PubMedDate not supplied

Congenital hyperthyroidism: autopsy report.

We report the autopsy of a stillborn fetus with congenital hyperthyroidism born to a mother with untreated Graves' disease, whose cause of death was congestive heart failure. The major findings concerned the skull, thyroid, heart, and placenta. The cranial sutures were closed, with overlapping skull bones. The thyroid was increased in volume and had intense blood congestion. Histological examination showed hyperactive follicles. The heart was enlarged and softened, with dilated cavities and hemorrhagic suffusions in the epicardium. The placenta had infarctions that involved at least 20% of its surface, and the vessels of the umbilical cord were fully exposed due to a decrease in Wharton's jelly. Hyperthyroidism was confirmed by the maternal clinical data, the fetal findings of exophthalmia, craniosynostosis, and goiter with signs of follicular hyperactivity. Craniosynostosis is caused by the anabolic action of thyroid hormones in bone formation during the initial stages of development. The delayed initiation of treatment in the present case contributed to the severity of fetal hyperthyroidism and consequent fetal death.

Adult↗