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Biomedical subjects

R D Machado

Publications and source records attributed to R D Machado.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Angiotensin-II-induced angiogenesis in sponge implants in mice.

Stimulators of angiogenesis hold potential in promoting the development of collateral circulation in ischaemic tissue and accelerating would healing, but promote pathological vasoformation in angiogenesis-dependent diseases (solid tumours, atherosclerosis). The renin-angiotensin system is implicated in both beneficial angiogenesis and pathological vascular growth. We investigated the angiogenic activity of angiotensin II (AII) in a sponge implant model in mice; this peptide enhanced angiogenesis, as well as glycosaminoglycan (GAG, chondroitin sulfate proteoglycan) and protein synthesis in sponge matrix in mice in a dose-dependent fashion. Extensive angiogenesis was achieved with AII (1 microgram), which gave no significant increase in wet weight and protein and only a small effect on GAG. In the implants treated with AII (2 micrograms) no further increase in angiogenesis was observed, whereas a marked effect was shown in wet weight (326 +/- 15 vs. 424 +/- 27 mg), total protein (18 +/- 1 vs. 25 +/- 1 micrograms/ww) and GAG (98 +/- 10 vs. 160 +/- 13 ng/ww). The local blood flow has been determined by measuring the washout rate of 133Xe injected into the implants, correlated with histological evidence of vessel growth. This model of angiogenesis has allowed sequential studies of fibrovascular tissue infiltration simultaneously with histological and biochemical parameters of angiogenesis.

Angiotensin II↗
PubMedDate not supplied

Epidemiological aspects of the Brazilian spotted fever: serological survey of dogs and horses in an endemic area in the State of São Paulo, Brazil.

In order to obtain information on Brazilian spotted fever, a study in domestic animals was performed in the County of Pedreira, State of São Paulo, Brazil, where 17 human cases had been notified. Serum samples obtained from animals were tested by indirect immunofluorescence for detectable antibodies to spotted fever-group rickettsiae. Seropositivity was revealed in 12 (36.4%) of 33 dogs and seven (77.8%) of nine horses from the endemic area. For comparison, blood samples from dogs and horses from non endemic area were tested and four (12.9%) of 31 dogs and three (27.3%) of 11 horses were positive. The highest titers of antibodies by IFA (IgG > or = 1:1024) were found only in three dogs and six horses from endemic area. The results suggest that dogs as horses may serve as environmental sentinels for establishing the prevalence of foci of spotted fever in Brazil.

Animals↗
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Epidemiological aspects of the Brazilian spotted fever: seasonal activity of ticks collected in an endemic area in São Paulo, Brazil.

Ticks were collected from vegetation and animals at monthly intervals during one year (1993-1994) in an endemic area of Brazilian spotted fever in the Country of Pedreira, State of São Paulo. Six species of ticks were identified Amblyomma cajennense, Amblyomma cooperi, Amblyomma triste, Anocentor nitens, Rhipicephalus sanguineus and Boophilus microplus. Only the first species was sufficiently numerous to permit a quantitative study with seasonal activity, although the distribution and source of capture of other species were observed and are reported. This information is correlated with the epidemiology of tick-borne rickettsiosis.

Animals↗
PubMedDate not supplied

[Isolation of Corynebacterium diphtheriae from sperm fluid].

The isolation of toxigenic Corynebacterium diphtheriae from sperm is reported. The organism was identified through the investigation of fluorescence under the UV light, the presence of pirazinecarboxilamidase enzyme (Pyz), in vitro and in vivo and virulence methods (single radial immunodiffusion, cell culture, guinea pig intradermic test). The strain was initially considered nontoxinogenic by single radial immunodiffusion, but its virulence was observed afterwards, when we applied the tests already mentioned. The strain could be considered a "Diphtheroid" without adequate specification.

Corynebacterium diphtheriae↗
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Comparative evaluation of a simple and sensitive assay for detection of orthomyxo and paramyxoviruses.

Studies were done to evaluate comparatively the traditional HA assay and a more recently introduced lectin-neuraminidase (LN) methodology in search of a simple and sensitive assay for virus detection during laboratorial diagnosis. The results proved the value of LN assay as a sensitive methodology for detection of virus particles, presenting results at least equal to those obtained by HA (hemagglutination) assay, with significant values of accumulated frequencies for LN/HA factors (ratios between LN and HA titers) higher than two. The accumulated values of frequencies for LN/HA factors as high as four were very significant, 72.7% for influenzavirus and 60.7% for Newcastle disease virus (NDV), moreover accumulated frequencies for LN/HA factors even as high as 32 were due to influenzavirus (45.4%) and NDV (7.2%) samples. After the storage period, most of those concentraded samples that even did not present HA titers could be detected through LN assay, demonstrating a lower threshold for virus detection.

Animals↗
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Rocky Mountain spotted fever in an endemic area in Minas Gerais, Brazil.

Only one species of spotted fever-group rickettsiae that is pathogenic for humans has been isolated in Brazil, where few physicians are familiar with this disease. In order to obtain information on tick-borne rickettsiosis, a study was performed in the County of Santa Cruz do Escalvado, State of Minas Gerais, Brazil, where a fatal clinical case confirmed by specific immunofluorescence had been reported. Serum samples obtained from 679 humans and 96 dogs were tested by indirect immunofluorescence for detectable antibodies to spotted fever-group rickettsiae, the criterion for a positive result being a titer > or = 1:64. Seropositivity was detected in 7.14% of the humans sera examined and 13.68% of the dogs. We discuss the significance of these findings and formulate some questions, emphasizing the need for further investigation.

Adolescent↗
PubMedDate not supplied

Primary isolation of spotted fever group rickettsiae from Amblyomma cooperi collected from Hydrochaeris hydrochaeris in Brazil.

This paper reports the first isolation of a spotted fever group rickettsia from an Amblyomma cooperi ixodid collected from a capybara (Hydrochaeris hydrochaeris) in an endemic area of spotted fever in the County of Pedreira, State of São Paulo, Brazil. Isolation was performed in Vero cell culture and submitted to immunofluorescence, using antibody from Rickettsia rickettsii-positive human serum.

Animals↗
PubMedDate not supplied

Rickettsiae-infected ticks in an endemic area of spotted fever in the State of Minas Gerais, Brazil.

A study on tick-borne rickettsiosis was developed in the county of Santa Cruz do Escalvado, State of Minas Gerais, Brazil, where a clinical case of the disease, confirmed by necropsy, had been reported. Of the 1,254 ticks collected, 1,061 belonged to the Amblyomma genus, 57 to the Rhipicephalus sanguineus species, 81 to Boophilus microplus, and 46 to Anocentor nitens. The hemolymph test associated with Giménez staining showed that 18 of the 221 A. cajennense specimens, 1 of the 16 R. sanguineus, 1 of the 22 B. microplus, 3 of the A. nitens, and 1 of the A. ovale contained rickettsia-like microorganisms. Only 3 A. cajennense ticks were positive under direct immunofluorescence. A. cajennense was the only species found on humans.

Animals↗