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Biomedical subjects

P Beaudry

Publications and source records attributed to P Beaudry.

53 records · Page 3Linked to original sources
PubMed1983

Energy needs and growth in children with cystic fibrosis.

Children with cystic fibrosis (CF) frequently have growth retardation. Standard growth velocity is dependent on an adequate supply of energy. The effect of dietary counselling and high energy food supplementation on the growth of eight children (aged 4 to 9 years) with CF was determined. The 2-year study was divided into control and test periods each lasting 1 year. Only during the test period did the mean energy intake reach or exceed 100% of the recommended energy requirements. When energy intake increased, weight growth increased significantly (p less than 0.05). Even with pancreatic enzyme replacement, the CF subjects had increased fecal energy losses. Thus, since dietary energy intake would overestimate energy available for metabolism, absorbed energy was determined. There was a positive linear relationship between absorbed energy and weight gain (p less than 0.01). Normal rates of weight gain were seen once absorbed energy intakes reached 100-110% of requirements. The children grew in height and weight at normal rates during the test period, whereas they showed retarded growth during the control period. Our data provide evidence that children with CF have inadequate energy intakes. Furthermore, we have shown that absorbed energy intake is the principal factor limiting the growth of CF children in the age group studied. Finally, it is possible to promote normal growth in CF children with dietary counselling and high energy supplements.

Body Height↗
PubMed1979

Cation-induced regulatory mechanism of GTPase activity dependent on polypeptide initiation factor 2.

Initiation factor IF-2 ribosome dependent GTP hydrolysis (uncoupled GTPase) presents a bell-shaped pH profile which is shifted by changes in ionic strength. At low ionic strength (I = 25 mM) the maximal hydrolytic activity occurs at pH 7.5; when the ionic strength is increased the pH optimum of the reaction is shifted toward more acidic values. Such behavior can be satisfactorily explained as the effect of an electrostatic potential developed by a neighboring polyanion, presumably RNA, on the catalytic site. The addition of fMet-tRNAfMet or AcPhe-tRNAPhe and messenger RNA (coupled GTPase) changes the ionic strength--pH characteristics of the reaction. Thus there is an effect, direct or indirect, of components located at the ribosomal P site. Investigation of the effect of neighboring polyanions on the catalytic activity of the factor-dependent ribosomal GTPases can be seen to provide information about their functional significance that is complementary to that gained from direct structural studies.

Escherichia coli↗
PubMed1978

Protons and Mg2+ cations as probes in investigating the role of GTP in initiation complex formation.

fMet-tRNAfMet binding to both 30-S subunits and to 70-S particles is dependent on both pH AND Mg2+ concentration: for fMet-tRNAfMet binding to 70-S particles, variations of pH and Mg2+ concentration are tightly interdependent. This behavior can be interpreted by the polyelectrolyte theory as a direct consequence of the fact that the binding occurs in a polyanionic micro-environment. The pH-dependent binding to 70-S particles clearly shows the involvement of two prototropic groups which appear to be those carrying out GTP hydrolysis, therefore directly linked to initiation complex formation; in the presence of a non-hydrolyzable analogue to GTP, guanosine 5'-[beta, gamma-imido]triphosphate, the binding of fMet-tRNAfMet shows much less interdependence between variation of pH and Mg2+ concentration.

Binding Sites↗
PubMed1977

Antithrombin III and Factor VIII in patients with neoplasms.

Possible increased activation of the coagulation pathway was measured in a group of patients with neoplastic diseases. In addition to standard tests, the thromboplastin generation test, thrombin generation test and immunologic and coagulant activities of both Factor VIII and antithrombin III were utilized in the evaluation. The correlation between immuno-Factor VIII (VIII-Ag) and its clotting activity (VIII-C1) was good (r = 0.83). In contrast, this was not the situation for antithrombin III-Ag and its clotting activity. Thromboplastin generation was accelerated in 60% and thrombin generation was accelerated in 40% of the patients. Fibrinogen was elevated in half the cases: in most of these patients, thrombin times were slightly prolonged. These results indicate that some patients who have cancer have abnormal clotting patterns and are often in a potentially hypercoagulable state that is reflected by the thromboplastin generation test, thrombin generation test, and high levels of Factor VIII (both VIII-Ag and VIII-C1).

Adolescent↗
PubMed1975

Relationship of arterial-alveolar nitrogen tension to alveolar-arterial oxygen tension, lung volume, flow measurements, and diffusing capacity in cystic fibrosis.

Pulmonary function in children with cystic fibrosis was assessed by the arterial-alveolar PN2 difference adjusted to sublingual temperature. The resulting values were compared with the alveolar-arterial PO2 difference, arterial PCO2, and standard measurements of lung volume, flow, and diffusing capacity. The arterial-alveolar PN2 difference was nearly one half of the PO2 difference, both early in the disease and at a more advanced stage. Analysis taking into account the O2 dissociation curve and the possibility that alveolar temperature is higher than sublingual temperature suggested that all of the PO2 difference could be explained in terms of ventilation-perfusion imbalance in gas-filled units of the lung. Reduction of fractional CO uptake with increasing PN2 difference suggested that the decrease in diffusing capacity in cystic fibrosis may be explained by ventilation-perfusion inequality. A significant relationship between arterial PCO2 and the PN2 difference supported the view that ventilation-perfusion inequality is the cause of CO2 retention when present. The PN2 and PO2 differences were abnormal before the standard tests of lung volume and flow, but in general, the correlation was excellent. Because the PN2 difference was not superior to the PO2 difference in detecting early disease, and because the technical problems in its measurement are considerable, it is not recommended as a routine measurement.

Adolescent↗
PubMedDate not supplied

14-3-3 protein, neuron-specific enolase, and S-100 protein in cerebrospinal fluid of patients with Creutzfeldt-Jakob disease.

We explored simultaneously 14-3-3 protein, neuron-specific enolase (NSE), and one astroglial protein, S-100, recently proposed as Creutzfeld-Jakob disease (CJD) markers, in the cerebrospinal fluid (CSF) of 129 patients with suspected CJD. Cutoff values for NSE and S-100 were established at 25 and 2.5 ng/ml, respectively. The highest sensitivity was observed for S-100 (94.2%) followed by 14-3-3 (89.8%) and NSE (79.7%), while the highest specificity in CJD diagnosis was obtained with 14-3-3 protein (100%) as compared with NSE (91.5%) and S-100 (85.4%). No influence of sex, genotype at codon 129 of the prion protein gene, time between sampling, and death or disease duration has been found. Based on 90 cases initially referred as 'probable' or 'possible' CJD, with 14-3-3, NSE, or S-100 we could correctly discriminate between 'CJD' or 'non-CJD' categories in 94.4, 86.5, and 90% of the cases, respectively. When limited to 'possible CJD' cases, diagnosis based on one of the three CSF proteins was accurate in 98, 90.7 and 87.3%, respectively. In view of the fact that the CSF 14-3-3 protein test alone has the highest specificity and good sensitivity, it appears that there is no additional advantage at the moment to include NSE and/or S-100 protein in the exploration of clinically suspected CJD cases.

14-3-3 Proteins↗