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Biomedical subjects

M L Machado

Publications and source records attributed to M L Machado.

7 recordsLinked to original sources
PubMed1997

Occupational respiratory allergic disease induced by Passiflora alata and Rhamnus purshiana.

BACKGROUND: There has been an increase in the incidence of occupational asthma along with better understanding of its pathophysiologic mechanisms and etiologic factors. There are no reports of patients with asthma and rhinitis to Passiflora alata (passion flower) and Rhamnus purshiana (cascara sagrada). METHODS: We describe two substances of plant origin as causal agents of occupational allergic respiratory diseases in a patient who worked in a pharmacy devoted to the manual preparation of products. RESULTS: Skin testing and Western blot confirmed the sensitization of the patient to these plant extracts in vivo and in vitro, respectively. Bronchial challenge confirmed the cause-effect relationship between the allergen exposure and the diseases. CONCLUSIONS: We conclude that Passiflora and cascara sagrada are two new etiologic agents of IgE-mediated occupational asthma and rhinitis. The present study also serves to alert physicians to the risks associated with work in pharmacies devoted to manual preparation of plant extracts, emphasizing the importance of the use of protective measures in these environments.

Adult↗
PubMed1993

Evaluation of the relationship between PAH content and mutagenic activity of fumes from roofing and paving asphalts and coal tar pitch.

Fume condensates from asphalt and coal tar pitch were evaluated to determine if polycyclic aromatic hydrocarbon (PAH) composition, crude oil source, or temperature at which the fume was generated correlated with mutagenic activity. The fume condensates were tested for mutagenic activity using a modified Ames Test. Benzo[a]pyrene (BP) and other PAHs were detected in all samples. The concentration of BP in coal tar pitch was 18,100 ppm while the concentration in asphalt was less than 6 ppm. Coal tar fumes contained between two and three orders of magnitude more BP, as well as other PAH species, than asphalt fumes. Coal tar fume condensates were also approximately 100 times more mutagenic than those of asphalt. Generation temperature, crude oil source, and/or process conditions affected the PAH concentrations but not the mutagenicity in roofing asphalt fume condensates. With paving asphalt fumes, PAH content and mutagenicity varied with crude oil source but not with processing conditions; due to limited data, it was not possible to determine the effect of generation temperature. Coal tar pitch fumes generated at 316 degrees C contained significantly higher concentrations of PAHs than those generated at 232 degrees C and the mutagenic activity generally paralleled the PAH content. A subset of the paving asphalts demonstrated good correlation between mutagenicity and three- to seven-ring PAH content. These results indicate that asphalt fumes are far less mutagenic than coal tar fumes. Asphalt fumes differ in their ability to induce mutagenic activity, and, most likely, in their potential carcinogenicity.

Air Pollutants, Occupational↗
PubMed1990

Distal monosomy of the long arm of chromosome 6 (6q25----6qter) inherited by maternal translocation t(6q;17q)

Two half-sisters with distal monosomy of the long arm of chromosome 6 (q25----qter) inherited by maternal translocation t(6q;17q) were investigated. The clinical manifestations of these patients are compared with eight cases reported in the literature for further characterization of the 6q-syndrome. The cytogenetic diagnosis of alterations involving small chromosome fragments and the different origins of this type of deletion are also discussed.

Abnormalities, Multiple↗
PubMed1986

Application of modified Salmonella/microsome prescreen to petroleum-derived complex mixtures and polynuclear aromatic hydrocarbons (PAH)

In some cases, the Salmonella mutagenicity assay may fail to predict the carcinogenic potential of PAH (and of complex mixtures containing PAH) because of nonoptimal in vitro metabolic activation parameters. In this study, 7 petroleum-derived complex mixtures, as well as a number of individual PAH which were representative constituents of such mixtures, were tested in a Salmonella prescreen using quadrant plates with rat or hamster S9 at concentrations approximately 2-8 times those used in the standard assay. Some PAH (perylene, quinoline, benzo[b]chrysene, phenanthrene, anthracene) were optimally activated to mutagens by S9 at 400 microliters/plate. Rat S9 was similar to hamster S9 for most tested PAH, but anthracene and quinoline mutagenicity was enhanced by hamster S9. All 7 complex mixtures were more mutagenic with 200-400 microliters/plate S9; rat was generally slightly more efficient than hamster. Modifying this assay to include a prescreen using a range of S9 concentrations (and perhaps from species other than rat) may improve prediction of the potential carcinogenicity of complex petroleum-derived mixtures.

Animals↗
PubMed1985

Petroleum distillates suppress in vitro metabolic activation: higher [S-9] required in the Salmonella/microsome mutagenicity assay.

To determine if standard conditions used in the Salmonella/mammalian microsome mutagenicity assay could reliably screen complex petroleum samples, two high-boiling (700-1,070 degrees F) distillates and their separated aromatic fractions were tested. The initial mutagenic activities were inconsistent with the samples' known polyaromatic hydrocarbon (PAH) contents and observed potencies in a dermal carcinogenesis bioassay. A significant mutagenic response was observed only at S-9 concentrations 5 to 10 times higher than those used in the standard assay, supporting the use of elevated levels of S-9 in the Salmonella/microsome assay to assess the carcinogenic potential of petroleum-derived materials. All four samples masked the expected mutagenic activity of added PAHs (benzo[a]pyrene and perylene). Data suggested that petroleum distillates suppress the functional efficacy of the S-9; possible mechanisms are discussed.

Animals↗
PubMedDate not supplied

[Surgical treatment of hepatocarcinoma in cirrhosis].

In 1986, our institution published the first results of surgical résection of hepatocarcinoma in cirrhotic patients. The aim of this paper is to present long term results of this surgical management. From April 1978 to February 1992, 74 patients were operated on at the surgical clinic of University Medical Center of Rennes (35000) France. There were 60 hepatectomies and 14 transplantations. The mean age was 60.2 years-9 years and the sex ratio: 70 males and 4 females. The etiology was alcoholic in 43 patients (58%), post hepatitis (B and C) in 22 patients (30%) and due to hemochromatosis in 9 patients (12%). According to the Child Pugh classification, 48 patients were Child A, 11 Child B and one Child C in the hepatectomy group and 9 patients Child A and 5 Child B in transplantation group. The operative mortality was 10% in hepatectomy group and 35.7% in liver transplantation group. Overall survival was 61.8% at 1 year, 47.1% at 2 years, 38.2% at 3 years and 20% at 5 years. 5 year survival is 21.4% after transplantation and 18.5% after resection. This difference is not significant. In conclusion, according to 5 years survival and to operative mortality the treatment of choice is hepatectomy in HCC in cirrhotic patients. However the best treatment is the prevention of cirrhosis.

Actuarial Analysis↗