Montreal Children's Hospital

About: Montreal Children's Hospital is a healthcare organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 3842 authors who have published 4816 publications receiving 200198 citations.

Developmental aspects of glutathione S-transferase B (ligandin) in rat liver.

Abstract: The postnatal development in male Sprague-Dawley rats of hepatic glutathione S-transferase B (ligandin) in relation to the other glutathione S-transferases is described. The concentration of glutathione S-transferase B in 1-day-old male rats is about one-fifth of that in adult animals. The enzyme reaches adult concentrations 4-5 weeks later. When assessed by substrate specificity or immunologically, the proportion of transferase B relative to the other glutathione S-transferases is high during the first week after birth. At this age, 67.5% of the transferase activity towards 1-chloro-2,4-dinitrobenzene is immunoprecipitable by anti-(transferase B), compared with about 50% in adults and older pups. Between the second and the fifth postnatal week, the fraction of transferase B increases in parallel fashion with the other transferases in hepatic cytosol. Neither L-thyroxine nor cortisol induce a precocious increase in glutathione S-transferase activity. Phenobarbital did induce transferase activity towards 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene in both pups and adults. The extent of induction by phenobarbital was a function of basal activity during development such that the percentage stimulation remained constant from 5 days postnatally to adulthood.

Mitochondrial methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase, and formyltetrahydrofolate synthetases.

Abstract: Folate‐mediated metabolism involves enzyme‐catalyzed reactions that occur in the cytoplasmic, mitochondrial, and nuclear compartments in mammalian cells. Which of the folate‐dependent enzymes are expressed in these compartments depends on the stage of development, cell type, cell cycle, and whether or not the cell is transformed. Mitochondria become formate‐generating organelles in cells and tissues expressing the MTHFD2 and MTHFD1L genes. The products of these nuclear genes were derived from trifunctional precursor proteins, expressing methylenetetrahydrofolate dehydrogenase–methenyltetrahydrofolate cyclohydrolase, and formyltetrahydrofolate synthetase activities. The MTHFD2 protein is a bifunctional protein with dehydrogenase and cyclohydrolase activities that arose from a trifunctional precursor through the loss of the synthetase domain and a novel adaptation to NAD rather than NADP specificity for the dehydrogenase. The MTHFD1L protein retains the size of its trifunctional precursor, but through the mutation of critical residues, both the dehydrogenase and cyclohydrolase activities have been silenced. MTHFD1L is thus a monofunctional formyltetrahydrofolate synthetase. This review discusses the properties and functions of these mitochondrial proteins and their role in supporting cytosolic purine synthesis during embryonic development and in cells undergoing rapid growth.

Plasma amino acids in 3/sec spike-wave epilepsy

Abstract: Plasma levels of 14 amino acids were determined in 44 probands with 3/sec spike-wave epilepsy, 27 of their first-degree relatives, and 22 controls. Six ratios of metabolically related amino acids were also calculated. Statistically significant differences were found for 7/20 variables when the experimental and control probands were compared, and for 6/20 variables when the relatives were compared with controls. Tau, Asp, and Tau/Glu were decreased and Glu was increased in both the experimental probands and their first degree relatives. When discriminant analysis was used, age- and sex-matched epileptic probands could be distinguished from the age- and sex-matched control probands with 100% accuracy employing only 3 amino acids (Asp, Glu, Val) and one ratio (Thr/Ser).

The significance of electroencephalographic abnormality in behaviour-problem children.

Abstract: The study of 200 problem children, 100 with abnormal EEG. tracings and 100 with normal records showed: 1. There was a high correlation between abnormal EEG.s and developmental delay, poor control of impulses, poor motor co-ordination and inadequate social adaptation. 2. Relations between EEG. tracings and thumb sucking, nail biting, hearing deficit, hostility, lying, stealing, percepto-motor disturbance and hyperactivity were significant. 3. The locations of abnormal EEG. records in the temporal lobe and subcortical regions and the diffuse type stand out as the overwhelming majority compared to other locations and types of EEG. The significance of these areas in the C.N.S. integrative function and particularly in behaviour, is well established. 4. Some of the signs and symptoms may be interpreted as direct consequences of developmental immaturity in the C.N.S. (e.g. thumb sucking, poor motor co-ordination, percepto-motor co-ordination disturbance, hyperactivity etc.), while others such as inadequate social adaptation, hostility, stealing, lying are the result of poor integrative ability of a C.N.S. handicapped by dysfunction, which is minimal as revealed by EEG. record. Four nosological groups and nine signs and symptoms were statistically significant out of ten nosological groups and sixty signs and symptoms respectively. In view of this result it could be assumed that the majority of cases are not the result of predisposed C.N.S. but possibly due to various environmental influences.