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Biomedical subjects

C de Souza

Publications and source records attributed to C de Souza.

11 recordsLinked to original sources
PubMed2001

Ixodes (Haemixodes) longiscutatum Boero (new status) and I. (H.) uruguayensis Kohls & Clifford, a new synonym of I. (H.) longiscutatum (Acari: Ixodidae).

Females of Ixodes (Haemixodes) uruguayensis Kohls & Clifford, 1967, a species whose adults were unknown until the present, were obtained in the laboratory from engorged nymphs collected on rodents (Scapteromys tumidus and Oxymycterus nasutus) in the counties of Maldonado and San José, Uruguay. Morphological characters of these females were identical to those given in the description of the female of Ixodes longiscutatum Boero, 1944. I. uruguayensis is, thus, relegated to a junior subjective synonym of I. longiscutatum. However, because of the unique morphological characters of the immature stages, the validity of the subgenus Haemixodes Kohls & Clifford, 1967 is not questioned. Therefore, the new status of Ixodes (Haemixodes) uruguayensis Kohls & Clifford, 1967 is Ixodes (Haemixodes) longiscutatum Boero, 1944.

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↗
PubMed1996

A well-type ionization chamber geometric correction factor.

To correct for the influence of source configuration on the measured activity of spherical and cylindrical brachytherapy sources, a geometric correction factor was calculated for the Standard Imaging HDR-1000 well-type ionization chamber. A Fortran program modelled each source as a lattice of point sources. Because of the cylindrical symmetry of the well chamber, it could be uniquely modelled by point detectors along the perimeter of the radial plane of the detection volume. Path lengths were calculated and attenuation factors were applied to each source-detector point combination individually. The total dose rate at each detection point was found through a Sievert summation of the point source contributions. For 137Cs sources with identical activities, a correction factor of 0.965 +/- 0.005 was calculated, equal to the ratio of the dose rate of the cylindrical source to that of the sphere. Experimental verification using a Nuclear Associates 67-809 series cylindrical sources and an Amersham spherical 137Cs source yielded a correction factor of 0.958 +/- 0.016.

Brachytherapy↗
PubMed1994

The stapedial reflex in cephalic tetanus.

Three patients are presented with cephalic tetanus following injuries to the face. Two were adults and one a child. All three had bilateral VIIth cranial nerve involvement and one patient also presented with involvement of the IIIrd, IVth and VIth cranial nerves. The patients initially an ipsilateral VIIth cranial nerve weakness which later in the course of the illness developed into hyperactivity of the VIIth cranial nerve. The contralateral VIIth cranial nerve demonstrated a similar pattern. The stapedial reflex was tested serially. The stapedius muscle activity preceded that of the muscles of the face thus serving as an indicator of improvement or impending deterioration. Deflections measuring more than 1 cm, on stapedial reflex threshold testing, were indicative of stapedial reflex spasm. In the stapedial reflex decay test, both ill-sustained (intermittent) and sustained spasms of the stapedius muscle were seen.

Acoustic Impedance Tests↗
PubMed1992

Effects of three compounds extracted from Morinda lucida on Plasmodium falciparum.

The effects of three compounds, digitolutein (1), rubiadin 1-methyl ether (2) and damnacanthal (3) extracted from the stem bark and the roots of Morinda lucida Benth. on the growth of Plasmodium falciparum in vitro were investigated. The number of parasites (schizonts) decreased significantly in a dose-dependent manner, and 100% of inhibition was obtained with 30 to 40 micrograms of each compound tested. The IC50 values were calculated.

Animals↗
PubMed1989

Antimalarial effects of eight African medicinal plants.

Crude hot water extracts from eight medicinal plants collected in Togo, West Africa, were examined for antimalarial properties against Plasmodium falciparum using an in vitro test. The activity differed with the plant species with extracts of Cassia siamea, Jatropha gossypiifolia and Pavetta crassipes capable of 100% inhibition.

Animals↗