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Biomedical subjects

M F Costa

Publications and source records attributed to M F Costa.

At least 19 recordsLinked to original sources
PubMed2005

Serologic immunoreactivity to Neospora caninum antigens in dogs determined by indirect immunofluorescence, western blotting and dot-ELISA.

Neospora caninum, is a coccidian protozoan known as a major cause of bovine abortion and canine neuropathies. The aim of the present study was to develop a reliable and quick test to detect antibodies to N. caninum in dog sera. Sixty-five serum samples from dogs, including 35 positive and 30 negative for N. caninum antibodies were used for standardization of the test. In parallel, immunoreactivity of the sera to Toxoplasma gondii antigens was investigated using a passive agglutination test. A dot-ELISA test, using soluble extract of N. caninum tachyzoites on nitrocellulose ester membranes, was developed and standardized. SDS-PAGE and complementary analysis of reactivity by Western blotting were used for the characterization of the immunoreactive fractions of all tested sera. The sensitivity and specificity of the dot-ELISA were 94 and 73%, respectively, compared to IFAT at a cut-off of 1:50, and 87 and 100% compared to IFAT at a cut-off of 1:25. Among the sera that tested positively for both IFAT and dot-ELISA, only 8.6% were reactive to T. gondii. The most immunoreactive fractions in Western blots were the 14-, 33-, 42- and 55 kDa bands, with percentages of 42, 60, 42 and 37%, respectively. The 60 kDa band showed a non-specific reaction in 43% of neosporosis-negative animals by both dot-ELISA and IFAT. These results indicate that the dot-ELISA using N. caninum antigen present good sensitivity and specificity, and might be used as a screening test to detect antibodies to N. caninum in dogs.

Animals↗
PubMed2004

Contrast sensitivity threshold measured by sweep-visual evoked potential in term and preterm infants at 3 and 10 months of age.

Although healthy preterm infants frequently seem to be more attentive to visual stimuli and to fix on them longer than full-term infants, no difference in visual acuity has been reported compared to term infants. We evaluated the contrast sensitivity (CS) function of term (N = 5) and healthy preterm (N = 11) infants at 3 and 10 months of life using sweep-visual evoked potentials. Two spatial frequencies were studied: low (0.2 cycles per degrees, cpd) and medium (4.0 cpd). The mean contrast sensitivity (expressed in percentage of contrast) of the preterm infants at 3 months was 55.4 for the low spatial frequency (0.2 cpd) and 43.4 for the medium spatial frequency (4.0 cpd). At 10 months the low spatial CS was 52.7 and the medium spatial CS was 9.9. The results for the term infants at 3 months were 55.1 for the low spatial frequency and 34.5 for the medium spatial frequency. At 10 months the equivalent values were 54.3 and 14.4, respectively. No difference was found using the Mann-Whitney rank sum T-test between term and preterm infants for the low frequency at 3 or 10 months or for the medium spatial frequency at 3 or 10 months. The development of CS for the medium spatial frequency was equally fast for term and preterm infants. As also observed for visual acuity, CS was equivalent among term and preterm infants, suggesting that visual experience does not modify the development of the primary visual pathway. An earlier development of synapses in higher cortical visual areas of preterm infants could explain the better use of visual information observed behaviorally in these infants.

Contrast Sensitivity↗
PubMed2004

[Not Available].

Explore the source record for details and available documents.

Editorial↗
PubMed2004

[A hierarchical model for analysis of socio-economic variables and water contact patterns associated with the hepatosplenic form of schistosomiasis].

A study of factors associated with the hepatosplenic clinical form of schistosomiasis was carried out in an endemic area (Comercinho, Minas Gerais) where prevalence of Schistosoma mansoni infection was 70.4%. Of the 1,408 inhabitants aged two years and over, 1,162 (82.5%) participated in the study. Socio-demographic characteristics and reasons for water contacts of individuals with the hepatosplenic form (n = 73) were compared to those who did not present splenomegaly and eliminated (positive controls; n + 804) or did not eliminate S. mansoni eggs in stools (negative controls; n = 285). Multivariate analysis was performed, considering the existence of colinearity among socio-economic status of the family, running water in the household, and bathing in streams. The hepatosplenic form in children was strongly associated with occupation of the head of the family (manual workers) (OR = 11.4; 95% CI = 1.4 - 91.8), absence of running water in the household (OR = 7.7; 95% CI = 2.6 - 23.1), and bathing in streams (OR and 95% CI 7.6; 2.5-22.9 and 5.7; 1.3-25.5 for frequencies > weekly and <= weekly, respectively); bathing in streams, which implies intense contacts, was a consequence of the first two factors. Our results suggest that running water in the household can decrease morbidity from schistosomiasis because it reduces the need for intense contacts with streams.

English Abstract↗
PubMed2000

[Multiple sclerosis, spinal cord ependymoma and intracranial meningioma: case report].

We report the association a multiple sclerosis (MS), spinal cord tumour and intracranial tumor in a 63 years-old female patient with a 10 years history of relapsing/remitting MS. Symptoms usually remitted in response to costicosteroid therapy. In 1997 the patient presented with paraparesis and paresis of right arm which did not respond to corticotherapy. A spinal RMI revealed in the cervical spinal an intra spinal cord tumour, further diagnosed as ependymoma, and a parietal region meningioma. We call attention to this rare association of central nervous system tumour and MS, enphasizing the need for investigation of new and uncommon symptoms during the evolution of MS.

Brain Neoplasms↗
PubMed2000

The Bambuí health and ageing study (BHAS): methodological approach and preliminary results of a population-based cohort study of the elderly in Brazil.

OBJECTIVE: A cohort study has been designed to identify predictors of adverse health events in the elderly. The methodology of the study and preliminary descriptive results are presented. METHODS: The study population comprises all residents of Bambuí (Minas Gerais, Brazil), aged 60 or more years (n=1.742). From these, 92.2% were interviewed and 85.9% underwent clinical examination, consisting of haematological and biochemical tests, serology for Trypanosoma cruzi, anthropometric and blood pressure measures and electrocardiogram. Aliquots of serum, plasma and DNA were stored for future investigations. The baseline interview included sociodemographic characteristics, self-referred health condition and history of selected diseases, medication use, health service use, source of medical care, physical activities, smoking, drinking and eating habits, reproductive history, physical functioning, life events, social support and mental health. Individuals are being followed up annually. RESULTS: The following characteristics predominated among participants: women (60,0%), married (48.9%) or widowed (35.4%), people living in households with up to 2 residents (73.8%), heads of family (76.7%), people with monthly income between 1.00 and 2.99 Brazilian minimum wages (62.0%) and people with up to 4 years of schooling (89.1%). The median age was 68 years. Among the cohort members, only 1.7% were lost in the first follow-up. CONCLUSIONS: In general, the characteristics of the study population were very similar to those from other epidemiological studies of the elderly based on large Brazilian cities. The small number of losses to follow-up indicates that the choice of Bambuí was adequate, assuring the feasibility of a long term cohort study.

Aged↗
PubMed1998

Emergency physician's diagnosis of stroke subtype. An accuracy study.

OBJECTIVE: To evaluate the accuracy of clinical unstructured and structured diagnosis of acute stroke subtypes--cerebral haemorrhage (CH), cerebral infarction (CI), subarachnoid haemorrhage (SAH). METHODS: Sixty consecutive patients with acute stroke admitted to the Emergency Ward of a Brazilian University Hospital were examined by emergency physicians and computerised tomography (CT). We also compared it (physician's unstructured diagnosis) to two published clinical scoring systems (structured diagnosis--Guy's Hospital and Siriraj Hospital) applied to three other populations--regarding the operational characteristics of the tests. RESULTS: In our personal data, among 9 variables that could discriminate CH and CI, three have statistically significant difference (p < 0.05): headache (p = 0.0002) and vomiting (p = 0.02) occurred more frequently in CH patients, but previous stroke in those with CI (p = 0.04). Unstructured diagnosis proved valid for SAH, with a +LHR = 39.7; and to a smaller degree for CI (-LHR = 0.1). However, it exhibited low sensitivity for the diagnosis of CH. Structured tests (Guy's Hospital and Siriraj Hospital) also failed to confidently diagnose stroke subtypes, especially CH. CONCLUSIONS: Both clinical diagnosis (made by emergency physicians) and the available diagnostic tests fail to confidently discriminate CH and CI.

Adult↗
PubMed1997

[Knowledge and practices regarding stroke at a university hospital: Part 1. Education of the nursing staff: priorities for the treatment of cerebral infarction].

BACKGROUND AND PURPOSE: This study was undertaken to evaluate professionals working at a university hospital as to their knowledge and attitudes towards stroke. METHODS: Individuals working in the hospital were divided in two groups, health care workers (HCW) and non-health care workers (NHCW), and further subdivided according to level of schooling, resulting in seven strata. A closed questionnaire addressing epidemiology, risk factors, pathophysiology, typical symptoms, treatment, clinical course and personal attitudes towards smoking and blood pressure control, was applied to a random sample of each stratum (total n = 309). Kruskal-Wallis test for multiple comparisons of non-parametric data was used. RESULTS: Significant differences between the seven groups were found. Knowledge was strongly associated with being a HCW and with level of formal education (p < 0.001), even after excluding physicians from the analysis (p < 0.001). In NHCW groups, knowledge was not associated with level of education (p = 0.421). In these groups, personal fear of suffering a stroke was the only variable predictive of knowledge. Smoking and poor monitoring of blood pressure levels were also more common in strata with the lowest levels of education and among NHCW. CONCLUSION: Poor knowledge and wrong attitudes towards stroke are frequent among individuals working in a Brazilian university hospital. Although these results are not necessarily applicable to the general population, they will certainly be useful for the development of educational programs on stroke.

Cerebral Infarction↗
PubMed1997

[Knowledge and practices regarding stroke at a university hospital: Part 2. Medical education in the new era of treatment of cerebral infarction].

BACKGROUND AND PURPOSE: This study was undertaken to evaluate professionals working at a University Hospital as to their knowledge and attitudes towards stroke. METHODS: Individuals working in the hospital were divided in two groups, Health care workers (HCW) and non-Health care workers (NHCW), and further subdivided according to level of schooling, resulting in seven strata. A closed questionnaire addressing epidemiology, risk factors, pathophysiology, typical symptoms, treatment, clinical course and personal attitudes towards smoking and blood pressure control, was applied to a random sample of each stratum (total n = 309). The physicians group included 48 individuals. Kruskal-Wallis test for multiple comparisons of non-parametric data was used. Special attention was given to the wrong answers. RESULTS: Physicians correctly answered 92.6% of the questions. Their performance was superior to that of all other groups in all subgroups of questions. However, a large number of errors was found in questions addressing mortality and hospital mortality following stroke and the intimate relation between coronary and cerebral atherosclerosis. Treatment options in cerebral infarction are also poorly recognised. CONCLUSIONS: Although physicians general knowledge about stroke is good, they frequently do not perceive it as a critical disease requiring urgent hospital evaluation and care. The importance of a thorough cardiac evaluation following stroke and of the intimate relation between cardiac and cerebral ischemic disease is also unclear to this group. More hours of stroke teaching and practical training in stroke could possibly fill these gaps.

Cerebral Infarction↗
PubMed1992

Relationships between titers of antibodies immunoreacting against glycolipid antigens from Mycobacterium leprae and M. tuberculosis, the Mitsuda and Mantoux reactions, and bacteriological loads: implications in the pathogenesis, epidemiology and serodiagnosis of leprosy and tuberculosis.

Analysis of cell-mediated immunity [(CMI) as judged from the Mantoux, Fernandez, and Mitsuda reactions and the presence of granulomas in biopsy material] against humoral immunity (measurements of anti-PGL-I, PGL-Tb1, and SL-IV IgG and IgM antibody titers by ELISA) were performed in selected human populations. The investigations yielded data indicating that humoral (B-cell) responses preceded protective CMI in both tuberculosis and leprosy. The B-cell responses were unrelated to (unfavorable) cell-mediated delayed-type hypersensitivity (DTH). Notwithstanding the difficulty in inferring sequential events from studies in humans, it was shown that in humoral responses there was an initial rise of specific IgM immunoglobulins that switched afterward to IgG production during subclinical tuberculosis and leprosy infections. In patent tuberculosis disease the IgM-to-IgG switch was observed in the majority of patients; in patent leprosy disease the switch was impaired in the majority of patients. The clinical, immunological, and laboratory data indicated that the B-cell responses were suppressed as protective CMI was re-established in the patients during the protracted subclinical infection. According to the data, the diagnosis of subclinical tuberculosis and leprosy may be accomplished using ELISA. The yearly risk of tuberculosis in apparently healthy persons but with significant antibody titers was estimated at 44%; the yearly risk for leprosy has not yet been established. The clinical, epidemiologic, and diagnostic implications of these findings are discussed.

Antibodies, Bacterial↗
PubMed1985

Further characterization of [3H] flunitrazepam binding sites on cultured mouse astroglia.

Astroglial cells in primary cultures bind [3H]flunitrazepam with a high affinity on a single type of site and on a number of binding sites which increased during astroglial growth and differentiation. These binding sites show a particular pharmacological spectrum characterized by an inhibition of high affinity by RO-5-4864 (4'-chlorodiazepam), an anticonvulsant of the benzodiazepine family and by an inhibition of binding of lower affinities by diazepam clonazepam and clobazam. RO-5-4864 and clonazepam compete for the same binding site in astroglia. The heat stability and the hormonal modulation by thyroxine are similar for astroglia and neuronal-cells. Benzodiazepines modulate the astroglial 5-HT receptor. Such an effect could be a possible physiological response to benzodiazepines for astroglial cells in primary cultures.

Animals↗
PubMed1982

Uptake and binding of serotonin by primary cultures of mouse astrocytes.

Primary cultures of glia contain a high glial fibrillary acidic protein level and exhibit important glutamine synthetase activity. They take up serotonin via a high affinity carrier-mediated system with a Km of micromolar range. The Km of this transport process does not vary during cell growth or maturation; however, during the last period of morphological change induced by dibutyryl cyclic AMP, an increase in Vmax is observed. Chlorimipramine, fluoxetine and fenfluramine at 10-4 M inhibit this uptake. 3H-5-HT still binds to partially purified astrocytic membranes on a single type of site. During growth, neither KD nor Bmax were modified. During the maturation period, KD decreased to about 50% of its control level. Methysergide inhibits that binding.

Animals↗
PubMed1982

Partial characterization of temperature-sensitive mutants of foot-and-mouth disease virus, O1 caseros strain.

The preliminary characterization of four temperature-sensitive (ts) mutants of the O1 Caseros strain of foot-and-mouth disease virus is described. Two mutants, ts 6 and ts 40, showed a very low RNA synthesis rate at nonpermissive temperature and were classified phenotypically as RNA(-). Shift-up experiments demonstrated an incapacity to organize the RNA replicative process at nonpermissive temperature. Another mutant (ts 139) behaved phenotypically as RNA(+) and its virions were more thermolabile than the wild type virus, so the defect in this mutant is likely to be in one of its structural proteins. Finally, mutant ts 5 was phenotypically RNA(+); its leak production at nonpermissive temperature was high, and the shift-up experiment showed a defect that was expressed either late in the replicative cycle or continuously.

Animals↗
PubMed1981

Benzodiazepine receptors on primary cultures of mouse astrocytes.

Benzodiazepines bind to glial membranes on a single type of site, with a high affinity (KD = 5 x 10(-9) M) on about 100 fmol of sites per mg protein. The number of binding sites is increased when the membranes are treated with Triton X-100. Antiepileptic drugs such as clonazepam and phenobarbital and hypnotic drugs such as Ro-11-3128 and Ro-11-6896 are able in pharmacological concentrations to displace [3H]flunitrazepam from its glial binding sites.

Animals↗
PubMedDate not supplied

Effect of ventilation systems on prevalence of symptoms associated with "sick buildings" in Brazilian commercial establishments.

In this questionnaire study, the authors compared the prevalence of certain symptoms and signs associated with Sick Building Syndrome and perceptions relative to environmental discomfort of employees in a central-air-conditioned dropping center and in natural-ventilation commercial shops located on the streets of Niteroi, Rio de Janeiro, Brazil. There was a statistically significant higher prevalence of symptoms (e.g., water and itching of eyes, sore throat, nose irritation, difficulty breathing, skin irritation, sneezing) that were characteristic of Sick Building Syndrome in the air-conditioned building than in the naturally ventilated stores. The results indicated that there exists a continuing need for further research in Brazilian work environments.

Adult↗