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Biomedical subjects

J L Lopes

Publications and source records attributed to J L Lopes.

At least 19 recordsLinked to original sources
PubMed2004

Organ donation and transplantation in Brazil: university students' awareness and opinions.

This study was aimed at assessing university students' awareness and opinions about aspects of the law no. 10.221/01. This exploratory study was performed among students at the São Paulo Federal University-UNIFESP, from 2001 to July 2002, including 1284 undergraduates in the following courses: nursing, medicine, speech and language therapy, biomedicine, and ophthalmic technology. That data show that 47.7% (333) of undergraduates are aware of the kind of donation established by the new law. Among the adolescents of first and second grades, and courses, there was a difference on the awareness about the kind of donation (P =.000). Most undergraduates (57.6%, 402) agree with consented donation. However, the high percentage--35.1% (245)--that chose the alternative "I don't know" is remarkable. Results show that many undergraduates are unaware of the specifications of the technical files for transplants; only 48.3% (337) of them chose the correct answer, and 79.4% (554) do not believe that the order in the waiting list for transplants is respected. The conclusion is that it is worth emphasizing is that there are different opinions and levels of awareness among students, considering age, religion and religious practice, and course and level at school. In spite of unawareness and lack of belief in the principles of distribution of organs and tissue, most students are willing to be donors (68.2%).

Adult↗
PubMed2001

Genotoxic action of the sesquiterpene lactone centratherin on mammalian cells in vitro and in vivo.

Centratherin is a sesquiterpene lactone known for its antimicrobial, anti-inflammatory, and trypanocidal activities. The aim of this study was to determine the clastogenic and cytotoxic potential of centratherin in human lymphocytes and in mice. Human lymphocytes in culture were submitted to either continuous treatment or treatment during G(2) phase of the cell cycle. After continuous treatment the 0.2 microg/ml concentration induced a significant increase in total of chromosomal aberrations (CA) and sister chromatid exchange compared to control, and it reduced the mitotic index (MI). In the treatment during G(2) phase, centratherin induced a significant increase in the frequency of CA for all concentrations tested (0.1, 0.3, and 0.5 microg/ml). In the in vivo test system all three concentrations tested in mice (3.3, 6.7, and 13.3 mg/kg b.w.) induced a significant increase in CA compared to the negative control. On the basis of these results, centratherin showed clastogenic and cytotoxic activity on in vitro and in vivo mammalian systems.

Animals↗
PubMed2001

Acoustic transmission across a roughened fluid-fluid interface.

A set of tank experiments was performed to investigate acoustic transmission across a roughened fluid-fluid interface with the intention to test heuristic Bragg scattering predictions used to explain observations of anomalous transmission in field experiments. In the tank experiments, two immiscible fluids (vegetable oil floating on glycerin) formed the layers. Small polystyrene beads were floated at the interface to simulate roughness. An array of hydrophones placed in the bottom layer (glycerin) was used to measure the acoustic levels transmitted across the interface. This array was also employed as a beamformer to determine the apparent angle and sound speed of the scattered signals. Data were acquired at subcritical grazing angles in the frequency range of 100-200 kHz for three different bead diameters and for various configurations in which the locations of the beads floating on the interface were varied. Results of these measurements demonstrated that a significant amount of acoustic energy can be scattered into the bottom layer by beads floating at the interface. The scattered levels increased with increasing bead diameter. However, discrepancies occurred between observed propagation properties and the Bragg predictions. By comparing the processed tank data to a computer simulation of the same it was determined that these discrepancies are a consequence of near-field reception of the scattering by the bead array and ignoring the directionality of the scattering by the beads. Consequences to observations made in field experiments are discussed.

Journal Article↗
PubMed2000

A study of the trypanocidal and analgesic properties from Lychnophora granmongolense (Duarte) Semir & Leitão Filho.

Crude extracts from the aerial parts of Lychnophora granmongolense (Asteraceae) were bioassayed for trypanocidal (trypomastigote forms of Trypanosoma cruzi) and analgesic (writhing test) activities. The crude ethyl acetate extract from the leaves plus inflorescences exhibited trypanocidal activity but no analgesic activity in the writhing model of pain. The bioassay-guided fractionation of this extract yielded three trypanocidal compounds: the sesquiterpene lactones centratherin (lychnophorolide A) and goyazensolide and the flavonoid eriodictyol. The flavonoids homoeriodictyol, eriodictyol 7, 3'-dimethyl ether, velutin, chrysoeriol, dihydroisorhamnetin, rhamnazin and the sesquiterpene lactone lychnophorolide B were also isolated from the ethyl acetate extract. Such flavonoids did not show any trypanocidal activity. The isolated amount of lychnophorolide B was not enough to account for the full activity against T. cruzi.

Acetic Acid↗
PubMed1998

Effect of naturally occurring flavonoids on lipid peroxidation and membrane permeability transition in mitochondria.

The ability of eight structurally related naturally occurring flavonoids in inhibiting lipid peroxidation and mitochondrial membrane permeability transition (MMPT), as well as respiration and protein sulfhydryl oxidation in rat liver mitochondria, was evaluated. The flavonoids tested exhibited the following order of potency to inhibit ADP/ Fe(II)-induced lipid peroxidation, estimated with the thiobarbituric acid assay: 3'-O-methyl-quercetin > quercetin > 3,5,7,3',4'-penta-O-methyl-quercetin > 3,7,3',4'-tetra-O-methyl-quercetin > pinobanksin > 7-O-methyl-pinocembrin > pinocembrin > 3-O-acyl-pinobanksin. MMPT was estimated by the extent of mitochondrial swelling induced by 10 microM CaCl2 plus 1.5 mM inorganic phosphate or 30 microM mefenamic acid. The most potent inhibitors of MMPT were quercetin, 7-O-methyl-pinocembrin, pinocembrin, and 3,5,7,3',4'-penta-O-methyl-quercetin. The first two inhibited in parallel the oxidation of mitochondrial protein sulfhydryl involved in the MMPT mechanism. The most potent inhibitors of mitochondrial respiration were 7-O-methyl-pinocembrin, quercetin, and 3'-O-methyl-quercetin while the most potent uncouplers were pinocembrin and 3-O-acyl-pinobanksin. In contrast 3,7,3',4'-tetra-O-methyl-quercetin and 3,5,7,3',4'-penta-O-methyl-quercetin showed the lowest ability to affect mitochondrial respiration. We conclude that, in general, the flavonoids tested are able to inhibit lipid peroxidation on the mitochondrial membrane and/or MMPT. Multiple methylation of the hydroxyl substitutions, in addition to sustaining good anti-lipoperoxidant activity, reduces the effect of flavonoids on mitochondrial respiration, and therefore, increases the pharmacological potential of these compounds against pathological processes related to oxidative stress.

Animals↗
PubMed1992

Organochlorine pesticide residues in human milk in the Ribeirão Preto region, state of São Paulo, Brazil.

Thirty-seven samples of human milk (colostrum) from donors living in the Ribeirão Preto region were analyzed to determine the levels of organochlorine pesticide residues. Donors were classified into two groups, i.e., occupationally exposed and non-exposed to pesticides. Other factors such as age, previous lactations, race, smoking habit, occupation, family income and educational level were also considered. Analysis was performed by preliminary lipid extraction followed by fractional partition on a column and finally by gas chromatography with an electron capture detector. Lindane was found in 32% of the samples in amounts of less than 0.001 mg/kg; heptachlor was found in 65% of the samples at mean levels of 0.001 mg/kg, i.e., a level five-fold lower than that established by FAO/WHO (1970) for cow's milk. Aldrin and endrin were not detected in any of the samples. Dieldrin was detected in only one sample at a level of 0.038 mg/kg, which is considered high. DDT and DDE amounts are reported as total DDT and at least one of these compounds was present in every sample. Amounts detected in donors occupationally exposed to pesticides ranged from 0.008 to 0.455 mg/kg (mean, 0.149 mg/kg), i.e., three times the limit established by FAO/WHO (1970), while values for donors who had not been exposed ranged from 0.002 to 0.072 mg/kg (mean, 0.025 mg/kg), i.e., half the limit. Considering the level of acceptable daily intake proposed by FAO/WHO (1973), lactents ingested 1% of the acceptable intake of lindane (all donors), 30% of the acceptable intake of heptachlor (all donors), 60% of the acceptable intake of DDT (non-exposed donors), and 3.7 times the acceptable intake of DDT (exposed donors).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Anodontites trapesialis: a biological monitor of organochlorine pesticides.

The mussel Anodontites trapesialis (Lam, 1819) was used as an indicator of organochlorine pollutants in the Pardo River, located in the municipality of Ribeirão Preto (21 degrees 07'S and 47 degrees 45'W), State of São Paulo, Brazil. Biological monitoring was performed for one year at the site of a sugar cane grove on the left bank of the river. Forty-three animals were placed in two aluminum enclosures on the river bottom at this site and 4 animals of each enclosure were sacrificed for pesticide analysis at 3-month intervals, each collection corresponding to one season of the year. The animals were found to have been exposed to DDT, lindane, heptachlor, aldrin and dieldrin. Endrin was not detected in any of the analyses.

Animals↗
PubMed1991

Sesquiterpene lactones from Vernonia.

Some informations about the sesquiterpene lactones isolated from Brazilian species of Vernonia are described, as well the results of tests developed with such compounds with respect to their anti-feedant, molluscicide, antimicrobial and analgesic properties.

Animals↗
PubMed1991

Biological monitoring of organochlorides using the limnic bivalves Anodontites trapesialis (Lam., 1819).

The mussel Anodontites trapesialis (Lam, 1819) was used as an indicator of organochloride pollutants in the Canoas River, located in the municipality of Mococa (21 degrees 25'08''S and 47 degrees W), State of São Paulo, Brazil. Biological monitoring was performed for one year at the site of an orange grove on the left bank of the river. Forty-five animals were placed in aluminum enclosures on the river bottom at this site and 4 animals were sacrificed for pesticide analysis at 3-month intervals, each corresponding to one season of the year. Pesticides were extracted by the method of Bedford et al., (1968), modified, and the analyses were performed by gas phase chromatography equipped with an electron capture detector. The animals were found to have been exposed to DDT, Lindane and Heptachlor. Variation in Aldrin and Dieldrin levels was not significant enough to permit inferences. Endrin was not detected in any of the analyses.

Animals↗
PubMed1991

Antimalarial activity of crude extracts from Brazilian plants studied in vivo in Plasmodium berghei-infected mice and in vitro against Plasmodium falciparum in culture.

1. Ninety-five crude extracts obtained with either organic solvents or water from 48 Brazilian plants or parts of plants were evaluated experimentally as blood schizontocides. Seventy-three extracts were obtained from 33 plants randomly collected using an empirical approach, and 22 from 15 "medicinal" plants. 2. The crude extracts were screened in vivo at up to 1.0 g/kg, po, for 4 days in mice infected with blood forms of Plasmodium berghei and parasitemia was determined on the fifth day. 3. Six plants, 2 randomly collected, Vernonia brasiliana and Eupatorium squalidum, and 4 "medicinal" plants, Acanthospermum australe, Esenbeckia febrifuga, Lisianthus speciosus, and Tachia guianensis, were partly active against the rodent malaria, i.e., they showed 40-50% inhibition of P. berghei multiplication. Forty-two plants whose extracts presented no antimalarial activity are reported. 4. Four extracts with antimalarial activity were also tested in vitro using P. falciparum cultures and two of them, V. brasiliana and A. australe, were active. Extracts of V. brasiliana caused about 50% inhibition of parasite multiplication at relatively low doses (40 ng/ml) as compared to chloroquine (30 ng/ml) and quinine (50 ng/ml). 5. The relatively high percentage of positive results obtained here for "medicinal" plants vs randomly chosen plants demonstrates the effectiveness of the ethnopharmacological approach to drug testing.

Animals↗
PubMed1984

[Chemoprophylaxis of schistosomiasis: molluscacidal activity of natural products--assays with adult snails and oviposition].

Data concerning the molluscicidal activity of 159 extracts from 84 Brazilian plants on Biomphalaria glabrata, the most important intermediate host of Schistosoma mansoni in Brazil, are presented. Seventy eight extracts (49,0%) showed activity against snails or eggs, but only twenty nine (18.2%) were active on both, snails and eggs. Extracts of two species (Mikania hirsutissima and Qualea multiflora) have shown to be lethals to adult snails at 10 ppm concentration.

Animals↗