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Biomedical subjects

R C Oliveira

Publications and source records attributed to R C Oliveira.

18 recordsLinked to original sources
PubMed2006

Respiratory viruses in children younger than five years old with acute respiratory disease from 2001 to 2004 in Uberlândia, MG, Brazil.

The main viruses involved in acute respiratory diseases among children are: respiratory syncytial virus (RSV), influenzavirus (FLU), parainfluenzavirus (PIV), adenovirus (AdV), human rhinovirus (HRV), and the human metapneumovirus (hMPV). The purpose of the present study was to identify respiratory viruses that affected children younger than five years old in Uberlândia, Midwestern Brazil. Nasopharyngeal aspirates from 379 children attended at Hospital de Clínicas (HC/UFU), from 2001 to 2004, with acute respiratory disease, were collected and tested by immunofluorescence assay (IFA) to detect RSV, FLU A and B, PIV 1, 2, and 3 and AdV, and RT-PCR to detect HRV. RSV was detected in 26.4% (100/379) of samples, FLU A and B in 9.5% (36/379), PIV 1, 2 and 3 in 6.3% (24/379) and AdV in 3.7% (14/379). HRV were detected in 29.6% (112/379) of the negative and indeterminate samples tested by IFI. RSV, particularly among children less than six months of life, and HRV cases showed highest incidence. Negative samples by both IFA and RT-PCR might reflect the presence of other pathogens, such as hMPV, coronavirus, and bacteria. Laboratorial diagnosis constituted an essential instrument to determine the incidence of the most common viruses in respiratory infections among children in this region.

Acute Disease↗
PubMed2005

Bone morphogenetic proteins: from structure to clinical use.

Bone morphogenetic proteins (BMPs) are multi-functional growth factors belonging to the transforming growth factor ss superfamily. Family members are expressed during limb development, endochondral ossification, early fracture, and cartilage repair. The activity of BMPs was first identified in the 1960s but the proteins responsible for bone induction were unknown until the purification and cloning of human BMPs in the 1980s. To date, about 15 BMP family members have been identified and characterized. The signal triggered by BMPs is transduced through serine/threonine kinase receptors, type I and II subtypes. Three type I receptors have been shown to bind BMP ligands, namely: type IA and IB BMP receptors and type IA activin receptors. BMPs seem to be involved in the regulation of cell proliferation, survival, differentiation and apoptosis, but their hallmark is their ability to induce bone, cartilage, ligament, and tendon formation at both heterotopic and orthotopic sites. This suggests that, in the future, they may play a major role in the treatment of bone diseases. Several animal studies have illustrated the potential of BMPs to enhance spinal fusion, repair critical-size defects, accelerate union, and heal articular cartilage lesions. Difficulties in producing and purifying BMPs from bone tissue have prompted the attempts made by several laboratories, including ours, to express these proteins in the recombinant form in heterologous systems. This review focuses on BMP structure, molecular mechanisms of action and significance and potential applications in medical, dental and veterinary practice for the treatment of cartilage and bone-related diseases.

Animals↗
PubMed2004

Study of hantavirus infection in captive breed colonies of wild rodents.

Wild sigmondontine rodents are known to be the reservoir of several serotypes of New World hantaviruses. The mechanism of viral transmission is by aerosol inhalation of the excreta from infected rodents. Considering that the captive breed colonies of various wild mammals may present a potential risk for hantaviral transmission, we examined 85 specimens of Thrichomys spp. (Echimyidae) and 17 speciemens of Nectomys squamipes (Sigmodontinae) from our colony for the presence of hantavirus infections. Blood samples were assayed for the presence of antibodies to Andes nucleocapsid antigen using enzyme-linked immunosorbent assay (ELISA). Additionally, serum samples from workers previously exposed to wild rodents, in the laboratories where the study was conducted, were also tested by ELISA to investigate prevalence of anti-hantavirus IgG antibodies. All blood samples were negative for hantavirus antibodies. Although these results suggest that those rodent's colonies are hantavirus free, the work emphasizes the need for hantavirus serological monitoring in wild colonized rodents and secure handling potentially infected rodents as important biosafety measures.

Animals↗
PubMed2001

The distribution of Biomphalaria spp. in different habitats in relation to physical, biological, water contact and cognitive factors in a rural area in Minas Gerais, Brazil.

A total of 256 sites in 11 habitats were surveyed for Biomphalaria in Melquiades rural area (State of Minas Gerais) in August and November 1999 and in March 2000. Of the 1,780 Biomphalaria collected, 1,721 (96.7%) were B. glabrata and 59 (3.3%) B. straminea. Snails were found in all habitats except in wells, with the largest mean numbers in tanks, seepage ponds and canals, and the smallest numbers in springs, rice fields and fishponds. People's knowledge of the occurrence of Biomphalaria at the collection sites and the presence of Biomphalaria ova were strongly correlated with the occurrence of snails, and distance between houses and collection sites, as well as water velocity were inversely correlated with Biomphalaria occurrence (p < 0.001). The strongest predictor o f Biomphalaria occurrence was the presence of tilapia fish in fishponds. Fourteen Biomphalaria (0.8% of all snails) found at 6 sites were infected with Schistosoma mansoni. Suggestions are made for the utilization of local people's knowledge in snail surveys and further studies are recommended on the possible use of tilapia for biological control of Biomphalaria in fishponds, as well as modeling of S. mansoni transmission and reinfection.

Animals↗
PubMed2001

Epidemic of jungle yellow fever in Brazil, 2000: implications of climatic alterations in disease spread.

Seventy-seven human cases of sylvatic yellow fever were reported in Brazil during the period January-June 2000. The first cases were reported 1 week after New Year's day and originated at Chapada dos Veadeiros, a tourist canyon site in Goiás state, near Brasília, the Brazilian capital. The laboratory procedures used for diagnoses included serology with an IgM capture assay and plaque reduction neutralization test, virus isolation in suckling mice and C6/36 cells, and immunohistochemistry. All cases were diagnosed by at least two different laboratory procedures, with the exception of the first three fatal cases, which were diagnosed on the basis of clinical and epidemiological information. The cases were reported in eight Brazilian states as follows: Goiás with 64.9% (50 cases); Amazonas (1); Bahia (10); Distrito Federal (1); Mato Grosso (4); Minas Gerais (2); Pará (1); São Paulo (2); and Tocantins (6). Patient ages were within the following ranges: 13-74 years old (mean 34.3), 64 (84.4%) were male, especially agricultural workers (n = 30), but tourists (n = 11), carpenters (n = 4), fishermen (n = 4), students (n = 3), truck drivers (n = 3), and other people (n = 22) were also sickened. The case fatality rate was 50.6% (39/77). In Bahia state, a serologic survey that was carried out has suggested a symptomatic/asymptomatic coefficient of 1:4. Field studies developed in Distrito Federal, Goiás, and São Paulo states showed that Haemagogus janthinomys was the mosquito species associated with the transmission. A single strain was also obtained from Aedes scapularis in Bahia. Epizootic occurrence (monkey mortality) was observed in 49 municipalities mainly in Goiás state, where 40 municipalities made reports, 21 of which also diagnosed human cases. Data obtained by the National Institute of Meteorology in Brazil showed an increase in temperature and rain in December 1999 and the first 3 months of 2000 in Goiás and surrounding states, which perhaps has contributed to the intense and widespread transmission of the yellow fever virus. The relatively small number of cases probably reflects the extensive use of yellow fever 17D-vaccine during the last 3 years, in which about 45 million doses were used. During the last months of 1999, 16 and 11 yellow fever cases were reported in Tocantins and Goiás states, respectively. It is noteworthy that the last reported autochthonous cases of sylvatic yellow fever in São Paulo and Bahia, both states outside the endemic/enzootic area, had occurred in 1953 and 1948, respectively.

Adolescent↗
PubMed1999

Periarthritis promotes gait disturbance in zymosan-induced arthritis in rats.

OBJECTIVE AND DESIGN: We studied the contribution of periarthritis and synovitis to gait disturbance in zymosan (Zy)-induced arthritis. METHODS: Sixty Wistar rats were subjected to injection of Zy (1 mg) into their right knee joints. A first group of animals (GI) had Zy injected through the intact skin. A second group (GII) had Zy injected directly into the articular cavity after excision of the skin and subcutaneous tissue surrounding the joint. Gait disturbance was evaluated using the rat-knee joint incapacitation test. Increase in vascular permeability and cell influx were assessed in joint fluids and joint histology was performed. RESULTS: Zy injection induced a dose-dependent gait disturbance which was maximal at the third/fourth hour of arthritis, being significantly greater in GI rats, whereas cell influx (neutrophils > or = 80%) was maximal at the sixth hour. Cell influx and increase in vasopermeability did not differ between both groups. Histology revealed no significant difference between GI and GII. A third group (GIII), subjected to immune-complex arthritis, that received anti-bovine serum albumin (BSA) antibodies intra-articularly and BSA i.v., did not present gait disturbance, despite the increase in cell counts. CONCLUSIONS: Vascular permeability increase and cell influx are phenomena independent of gait disturbance. Neutrophils do not seem to contribute to development of gait disturbance in Zy arthritis. Sensitization of specific pain receptors in periarticular rather than in synovial tissue is responsible for gait disturbance in Zy-induced arthritis.

Animals↗
PubMed1996

Pressor action of angiotensin I at the ventrolateral medulla: effect of selective angiotensin blockade.

In this study we explored the possibility that angiotensin-(1-7) (Ang-(1-7)) is involved in the control of blood pressure at the rostral ventrolateral medulla (RVLM) by determining the effect of angiotensin antagonists (DuP 753 and A-779) and the effect of the angiotensin converting enzyme inhibitor, ramiprilat on the pressor action produced by angiotensin I (Ang I). The pressor effect produced by bilateral microinjection of Ang I into the RVLM of anesthetized rats was not significantly altered by DuP 753 or by the ACE inhibitor ramiprilat. Conversely, the Ang-(1-7) antagonist, A-779, reduced significantly the pressor effect produced by Ang I. These data suggest that in our experimental condition Ang I was preferentially converted to Ang-(1-7) at RVLM, or that Ang I and/or one of its fragments acts through a receptor blocked by A-779.

Angiotensin I↗
PubMed1992

Familial aggregation of arterial blood pressure and possible genetic influence.

The aggregation of arterial blood pressure, weight, and height were compared between family members of children and adolescents with blood pressure percentiles at or above 95 (group 1) and at or below 50 (group 2). Weight, height, and systolic and diastolic blood pressures were significantly higher in siblings and target individuals of group 1 (p less than 0.001). Weight and systolic and diastolic blood pressures were significantly higher in mothers of group 1 (p less than 0.001). Covariant analysis comparing the average systolic and diastolic blood pressures of both groups controlled by age, age and weight, and age and Quetelet index revealed that the arterial blood pressure of mothers, siblings, and target individuals remained higher in group 1 (p less than 0.05 to p less than 0.001). These observations show a strong familial aggregation of arterial blood pressure not dependent only on physical development and also raise the question of a genetic basis as a possible mechanism of systemic arterial hypertension.

Age Factors↗
PubMed1989

Patterns of marihuana smoking among Brazilian students.

Changes in frequency of marihuana smoking over time were investigated by interviewing forty-seven Brazilian students from São Paulo between 18 and 24 years old, of both sexes. From their report, it was concluded that the course of smoking frequency follows two predominant patterns. In one of them, the 'Stable Pattern', subjects report increasing consumption up to a peak frequency where they remain for a relatively long and stable period of time. In the other one, the 'Descending Pattern', subjects report a gradual increase up to a peak, followed by a clear decline in rate of use. Two other patterns were also detected in a small number of subjects. The diversity of patterns identified stresses the difficulty in predicting the course of marihuana smoking frequency by young people. The relationship between marihuana smoking and the use of other drugs was also investigated. The only drugs that were reported to be regularly consumed by the majority of subjects were alcohol and tobacco, while 90% of the subjects reported having tried at least one other illegal drug.

Adult↗
PubMedDate not supplied

Dissociation of antibody responses during human schistosomiasis and evidence for enhancement of granuloma size by anti-carbohydrate IgM.

Immunoglobulin (Ig) G and IgM antibody levels to soluble egg antigens (SEA), adult worm glycoproteins (AWGP), carbohydrate antigens (CHO) and cationic exchange fraction 6 (CEF6) were measured in serum specimens taken from Brazilian patients with acute, intestinal, hepato-intestinal and hepatosplenic schistosomiasis mansoni. The antibody levels varied among the groups, with the highest anti-egg antigen responses in the acute patients and the highest anti-adult worm responses in patients with chronic disease. The responses to the component parts of the egg antigens were dissociated, with anti-carbohydrate IgG and IgM responses being highest in the acute infection group and anti-CEF6 IgG responses being uniform among the clinical groups. The possibility of a direct role for anti-CHO antibody responses in egg-induced pathology was investigated using the mouse lung model. The anti-carbohydrate monoclonal antibody NIMP/M45 significantly enhanced granuloma formation. Mice given NIMP/M45 produced granulomas larger than those of naive mice or mice given an unrelated monoclonal antibody, and as large as those produced by mice which had been presensitized to egg antigens. The independent regulation of responses to egg antigens may indicate that such responses are minimized to reduce the pathological consequences of infection whilst allowing the development of protective anti-worm responses.

Acute Disease↗
PubMedDate not supplied

The value of an enzyme-linked immunosorbent assay for the diagnosis of schistosomiasis mansoni myeloradiculopathy.

The role of serological tests on cerebrospinal fluid (CSF) in the diagnosis of neuroschistosomiasis has not been fully elucidated; the condition is essentially diagnosed on the basis of circumstantial evidence, which may lead to an erroneous diagnosis, especially in highly endemic areas. We therefore carried out a prospective case-control study in which we compared the concentrations of immunoglobulin G (IgG) specific for schistosome soluble egg antigen (SEA) present in the CSF of 54 patients with schistosomiasis mansoni myeloradiculopathy (SMMR) with those observed in a control group consisting of 41 patients with epidemiological and serological evidence of exposure to schistosomes, and with other neurological disorders that result in mild to moderate impairment of the blood-brain barrier. Anti-SEA IgG was estimated by an enzyme-linked immunosorbent assay. The sensitivity, specificity and positive and negative predictive values were 56%, 95%, 94% and 62% respectively. Likelihood ratios and the corresponding post-test probabilities were determined for 4 levels of anti-SEA IgG in CSF. A value below 0.1 micrograms/mL practically excluded the possibility of SMMR (post-test probability < 5%), a value above 1.4 micrograms/mL practically confirmed the diagnosis of SMMR (post-test probability > 96%), values of 0.1 to 0.5 microgram/mL had no diagnostic value (post-test probability approximately 45%), and values of 0.6 to 1.4 micrograms/mL were useful in some situations (post-test probability approximately 70%). We conclude that the estimation of anti-SEA IgG in the CSF is useful for the diagnosis of SMMR.

Adolescent↗
PubMedDate not supplied

[Search of antimeasles antibodies in HIV-infected children after basic immunization]

OBJECTIVE: To determine the presence of antimeasles antibodies in children perinatally infected with HIV and properly immunized. METHODS: A retrospective cohort study conducted in Belo Horizonte by the Universidade Federal de Minas Gerais, between 1995 and 1996. Twenty one children perinatally infected with HIV and 29 immunocompetent noninfected children were included in the study. Information about measles vaccination was obtained from patientś immunization charts. The presence of neutralizing antibodies against the measles was determined by the plaque reduction neutralization test and IgM was measured by ELISA. The level of significance was set at 5% in all the performed statistical analyses. RESULTS: Median age was 44.5 months for HIV-infected patients and 62.0 months for noninfected children (P=0.64). Both groups received on average two doses of antimeasles vaccine. All HIV-seronegative patients presented antimeasles antibody titers greater than 50 mIU/ml, whereas 57.1% of infected children presented titers above this value (P=0.0001). The geometric mean titer of neutralizing antibodies was significantly lower in the group of HIV-infected children (433.5 mIU/ml) than in noninfected children (1,668.1 mIU/ml), P=0.001. All patients in both groups were negative for antimeasles IgM. CONCLUSION: In the present study, HIV-infected children showed a lower seroprevalence of antimeasles antibody after immunization than noninfected children. These results emphasize the risk of acquisition of measles virus and the need to evaluate alternatives to the vaccination of HIV-infected children in an attempt to maximize the protection against the measles in this group of patients.

Journal Article↗