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Biomedical subjects

B Pinto

Publications and source records attributed to B Pinto.

At least 19 recordsLinked to original sources
PubMed1992

Responsiveness of tumorigenic and non-tumorigenic CHEF18 Chinese hamster cells to 1-beta-D-arabinofuranosylcytosine treatment.

In cultured mammalian cells, sister chromatid exchanges are easily induced by agents that perturb the scheduled timing of DNA replication. In this work a blockage of DNA synthesis induced by 1-beta-D-arabinofuranosylcytosine was applied to non-tumorigenic and tumorigenic CHEF18 Chinese hamster cells, and their responsiveness was compared. The data show that both the induction of sister chromatid exchanges and the reduction of the colony-forming ability were less extensive in non-tumorigenic than in tumorigenic CHEF18 cells. The results suggest that a tight control of the scheduled timing of DNA replication is present in non-tumorigenic CHEF18 cells and perhaps this feature avoids the generation of those chromosomal structures that are responsible for the abnormal induction of sister chromatid exchanges and for the elevated cytotoxicity seen in tumorigenic cells.

Animals↗
PubMed1991

Reduction of proliferative heterogeneity of CHEF18 Chinese hamster cell line during the progression toward tumorigenicity.

Doubling time and generation time represent two parameters by which the proliferation of cultured mammalian cells can be monitored. In this study we report the characterization of CHEF18 Chinese hamster cell line during the progression toward tumorigenicity by analysis of doubling time and generation time. The two parameters reveal that the proliferation was initially different, indicating the presence of a proliferative heterogeneity among the cycling cells. The progressive reduction up to the disappearance of this discrepancy suggests that a modification of the length of some phases of the cell cycle may have occurred during the progression toward tumorigenicity. However, the hypothesis that the shortening of doubling time might be due to a continuous coming out of cells from the cell cycle rather than to a shortening of the cell cycle is presented.

Animals↗
PubMed1991

Training breast self-examination: a research review and critique.

Despite an increase in knowledge about breast cancer, a relatively low percentage of women practice breast self-examination (BSE) regularly and competently. This article reviews the BSE literature with a focus on training of BSE components, discrimination training, and the effectiveness of training procedures. Methodological issues such as the absence of control groups, lack of criteria for termination of training and reliance on self-reports of BSE frequency are identified weaknesses of BSE training studies. A theoretical analysis of BSE highlights potential difficulties in maintaining regular practice of BSE. Recommendations regarding training of proficient BSE skills and promoting regular practice of BSE are offered, and suggestions for further refinement of BSE training and directions for future research are discussed. Promising avenues of research in BSE training technology include discrimination training (on real or simulated breast tissue) together with computerized assessment of skill proficiency.

Adolescent↗
PubMed1991

Preliminary investigation of suitable bacteria strains for the detection of bacteriophages in environmental polluted surface waters.

Different host-specific bacteriophages were monitored in several water systems together with the usual faecal contamination indicator bacteria (thermotolerant coliforms). The host bacteria used for the plaque assay were E. coli K12, E. coli K12 Hfr, E. coli CHfr and S. typhimurium LT2F+. S. typhimurium LT2F+ showed significantly lower phage counts than the three E. coli strains. The phages specific for E. coli K12 (somatic phages) were in high correlation (r = 0.86, r = 0.91; P less than 0.001) with other coliphages, but not with phages specific for S. typ. LT2F+ (r = 0.33; P less than 0.05). There was an high degree of correlation among phages of E. coli K12 Hfr, E. coli C Hfr and S. typhimurium LT2F+ (pilus F-carrying bacteria) (r = 0.96, r = 0.73, r = 0.75; P less than 0.001). Good correlation was seen between faecal coliforms and male-specific phages but not among faecal coliforms and E. coli K12-specific phages (r = 0.30; P less than 0.05). The relative suitability of host strains when using phages in the evaluation of faecal and viral pollution of aquatic environments is discussed.

Coliphages↗
PubMed1990

Hepatic alcohol dehydrogenase activity in alcoholic subjects with and without liver disease.

Alcohol dehydrogenase activity was measured in samples of liver tissue from a group of alcoholic and non-alcoholic subjects to determine whether decreased liver alcohol dehydrogenase activity is a consequence of ethanol consumption or liver damage. The alcoholic patients were classified further into the following groups: control subjects with no liver disease (group 1), subjects with non-cirrhotic liver disease (group 2), and subjects with cirrhotic liver disease (group 3). The non-alcoholic subjects were also divided, using the same criteria, into groups 4, 5, and 6, respectively. The analysis of the results showed no significant differences when mean alcohol dehydrogenase activities of alcoholic and non-alcoholic patients with similar degrees of liver pathology were compared (groups 1 v 4, 2 v 5, and 3 v 6. Alcohol dehydrogenase activity was, however, severely reduced in patients with liver disease compared with control subjects. Our findings suggest that alcohol consumption does not modify hepatic alcohol dehydrogenase activity. The reduction in specific alcohol dehydrogenase activity in alcoholic liver disease is a consequence of liver damage.

Alcohol Dehydrogenase↗
PubMed1979

Different types of hypercalciuria in patients with renal lithiasis and evidence of the calcium renal waste.

A study of normal subjects and patients with hypercalciuria and recurrent renal stones has identified three main types of hypercalciuria: complex, absorptive and renal. Complex hypercalciuria is a combination of absorption, renal leak and resorption factors. Absorption and renal leak were examined by means of a 45Ca test. Resorption is defined as an increase of the urinary calcium:creatinine ratio while the subjects are being maintained on an intake of 400 mg of calcium per 24 h.

Calcium↗
PubMed1978

Diethylaminoethanol-cellulose in the treatment of absorptive hyperoxaluria.

There were 22 patients in whom oxalate stones formed and who had absorptive hyperoxaluria treated with diethylaminoethanol-cellulose. In more than 2 years this form of treatment did not seem to have any serious side effects. It achieved a decrease of urinary oxalate values in all patients in whom oxalate hyperabsorption had been found. Diethylaminoethanol-cellulose is an anionic exchanger capable of retaining oxalate in vitro and in vivo.

Absorption↗
PubMed1978

Oxalate transport by the human small intestine.

Oxalate was transported in vitro by intestinal brush border cells from rabbit and human by a non-energy-dependent diffusion mechanism. An oxalate-binding protein that had an approximate molecular weight of 73,000 was identified in the human intestine (ileum), was localized in the cytosol cell fraction, and was affected by calcium and magnesium, which increased the oxalate binding.

Animals↗
PubMed1977

Interaction of uricine with uric acid and its effect on uric acid precipitation.

Uricine is a yellow-red pigment isolated from uric acid stones where it is always found. It binds to the uric acid, as shown by gel chromatography, at constant uric acid elution. It also increases the capacity of the uric acid to form larger aggregates and therefore the capacity of the uric acid to precipitate is enhanced. The uric acid-uricine aggregates may be separated by high speed sucrose centrifugation gradients.

Binding Sites↗
PubMed1977

Urinary excretion of uricine.

The excretion of uricine or yellowish-red pigment from uric acid stones and its binding by uric acid seems to affect the precipitation of uric acid. Uricine was determined by ion exchange chromatography followed by measurement of the alkaline fluorescence emission. The uricine urinary excretion and the uricine-uric acid potential binding were determined in 11 control subjects, 20 recurrent uric acid stone formers, seven calcium stone formers with hyperuricuria, and five gouty patients without urinary stone formation. Uricine excretion was increased in 11 uric acid stone formers, whereas it was normal in the rest of the patients. Uricine-uric acid potential binding was increased in many uric acid stone formers, despite the absence of uric acid urinary hyperexcretion, whereas it was normal in most of the calcium stone formers and was moderately increased in the gouty patients.

Adult↗
PubMed1976

Isolation and characterization of uricine from uric acid stones.

Uricine was found to be present in all uric acid stones tested, although another physiochemically related pigment was occasionally present. Uricine is of low molecular weight (28.2) and a preliminary analysis of its structure suggests that it is formed by two pyrrolic rings. It is a yellow pigment whose color is pH-dependent, shifting from reddish-yellow to green at pH 1.0. It is water soluble, but its solubility increases in alkaline solutions. Preliminary evidence suggests that uricine is related metabolically to bilirubin-like compounds.

Chemical Phenomena↗