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Biomedical subjects

R Charbonneau

Publications and source records attributed to R Charbonneau.

At least 37 records · Page 2Linked to original sources
PubMed1987

Variants of Alport's syndrome.

Variants of Alport's syndrome include mainly those associated with hereditary macrothrombocytopenia (and occasionally leukocyte inclusions) or with esophageal, tracheobronchial and genital leiomyomatosis. Within Alport's syndrome there appears to be no justification for differentiating those with nephritis and deafness from those with nephritis alone. However, in indirect immunofluorescence studies using the mouse monoclonal antibody, MCA-P1, which recognizes the glomerular basement membrane (GBM), reduced or absent binding was found in 20 of 42 cases of hereditary nephritis. Most of these showed typical ultrastructural GMB changes. These results suggest that there is probably a subset of patients characterized by typical GBM lesions and an absence, inaccessibility or abnormality of the GBM antigen recognized by MCA-P1.

Humans↗
PubMed1987

Relationship between in vitro digestion of proteins and in vivo assessment of their nutritional quality.

The relationship between the nature of in vitro digestion products and protein quality evaluation in rats was established. Eleven protein sources of animal and vegetable origin and of various purities were digested by pepsin then by pancreatin in a dialysis bag of 1,000 molecular weight cutoff. Animal proteins were generally better digested in vitro than vegetable proteins. Amino acid release partly reflected enzyme specificity and varied depending on the nature of the protein. Essential amino acids were generally released rapidly at the expense of non-essential amino acids. The composition of protein hydrolysis products was thus markedly different from that of the protein before digestion. Digestibility determination in rats showed much less variation between proteins than the in vitro method; the two digestibility measurements did not correlate. However, by using stepwise multiple regression analysis, the amino acid composition of in vitro digestion products was found to correlate with the protein efficiency ratio (PER) more accurately than protein composition (R2 = 0.981 and 0.934, respectively). A regression analysis with net protein ratio (NPR) gave lower R2 coefficients than with PER (0.941 and 0.921, respectively). When regression equations were employed to predict the PER and digestion products were used instead of protein composition, an improvement was seen for almost all the test proteins, especially beef, rapeseed and wheat gluten. Better evaluation of protein quality by the use of protein digestion products demonstrates the possible impact of amino acid availability on protein quality.

Amino Acids↗
PubMed1985

Structure and biological activity of polysomes stained with Coomassie blue.

Polysomes prestained with Coomassie blue were fractionated on sucrose density gradients giving rise to visible bands corresponding to different size classes of aggregates. Coomassie blue staining enhanced the capacities of brain and liver polysomes to synthesize proteins in vitro, including the synthesis of neuron-specific enolase. This positive action of the dye was restricted to polysomes and was not manifested when mRNAs isolated from prestained polysomes were tested in in vitro translation or reverse transcription, indicating that the action of the dye consists in stabilization of polysomal structure.

Animals↗
PubMed1985

Quantitative determination of catalase activity produced by Neisseria gonorrhoeae, Staphylococcus epidermidis, Neisseria meningitidis and other bacterial strains using the Catalasemeter.

The conventional catalase test only gives qualitative or semi-quantitative information of the amount of catalase activity produced. Using such a method, we have selected two strong catalase activity producers (Neisseria gonorrhoeae G-10, Staphylococcus epidermidis 66) and a weak producer (Neisseria meningitidis 34702). Quantitative determination of the catalase activity produced by these strains was done by the disk-flotation method using the Catalasemeter. The production of catalase activity in liquid culture by N. gonorrhoeae, S. epidermidis and N. meningitidis occurred mainly during the logarithmic growth phase. The maximum concentration of catalase activity found in these cultures was, for both strong producers, 160 units (U)/ml while it was around 20 U/ml for the weak producer. Some of the other bacteria tested showed high concentrations of catalase activity (130-162 U/ml) and these were: N. gonorrhoeae strain PR 77112 (penicillin resistant), Staphylococcus strain 7 (coagulase negative), Micrococcus sp. strains 2 and 42.

Bacteria↗
PubMed1981

Quantitative clinicopathologic study of cerebral amyloid angiopathy.

A rapid screening method is described for detecting amyloid angiopathy (AA) in the meningeal vessels with the use of thioflavin-S and fluorescence microscopy. AA was found most frequently in the brains of patients in whom senile degeneration of the Alzheimer type was complicated by severe arteriosclerosis, vascular hyalinosis and multiple infarcts (73 percent). In 69 randomly drawn mental hospital patients over the age of 55, the degree of AA was significantly correlated with the degree of organic symptomatology (r = .417, p less than .001). Multiple regression analysis, however, revealed that AA as a predictor of clinical symptoms was highly dependent upon another predictor, i.e., the quantity of senile plaques in the brain. In contrast, a highly significant and independent correlation was found between the clinical symptoms and AA in a control sample of 21 patients who had mental illnesses other than senile dementia (r = .683, p less than .001). In these patients the plaque count was very low and arteriosclerosis was prevalent. Among the clinical symptoms, Affect Lability was consistently most highly correlated with AA, whereas Disorientation was most highly correlated with the quantity of plaques.

Aged↗
PubMed1981

Quantitative clinicopathologic study of senile dementia.

In a randomized blind study of 69 mental hospital patients over 50 years of age, a highly significant correlation was observed between the clinical symptoms of organic brain disease and the quantity of senile plaques found in the brains at autopsy. A stepwise multiple regression analysis indicated that independent significant predictors of the quantity of plaques were the level or disorientation and the age of the patient. Additional clinical tests for intellectual deterioration, affect lability, and impairment of memory and judgment did not improve the predictive ability. The correlation between incidental pathologic changes unrelated to the senile form of cerebral degeneration and the clinical symptoms was highly significant, though not obvious. Only after removal of the effect of the quantity of plaques on the clinical symptoms (multiple regression analysis) did the effect of other pathologic processes become evident. A significant one-way fixed-effect relationship was noted between increasing quantity of symptoms and increasing quantity of plaques in 48 cases of senile dementia correctly diagnosed by the psychiatry staff. In the control group of 21 patients without senile dementia, the quantity of plaques was correlated with the age of the patients but not with their clinical symptoms.

Aged↗