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Biomedical subjects

C L Clow

Publications and source records attributed to C L Clow.

At least 37 records · Page 2Linked to original sources
PubMed1982

Prevention of mental retardation in offspring of hyperphenylalaninemic mothers.

Maternal hyperphenylalaninemia constitutes a potential hazard to the fetus for whom the risks of postnatal mental retardation, microcephaly, and congenital malformations are elevated. Preconception and intragestational dietary treatment can apparently improve the outcome of such pregnancies. In the absence of predictive mechanisms for pregnancies at risk and preventive measures involving reproductive counseling and treatment, there could be a rebound in the population frequency of mental retardation related to disorders of phenylalanine metabolism in subsequent generations. We describe a program serving a population of six million that includes screening, diagnosis, treatment, and counseling of the hyperphenylalaninemias. The program has recently added a simple dedicated register for males and females with hyperphenylalaninemia to supplement traditional methods for continuous surveillance of probands. We registered 153 patients: 43 females and 56 males with phenylketonuria, 23 females and 31 males with benign hyperphenylalaninemia, of which 22, 7, 27 and 5, respectively, had reached their 12th birthday in an 1981. Regional centers in the program provided counseling about the consequences of maternal hyperphenylalaninemia and the options to prevent them. No family has rejected the principle or fact of the Register and its goals.

Adolescent↗
PubMed1981

Outcome of early and long-term management of classical maple syrup urine disease.

The outcome of 8,400 treatment days in the lives of four patients with classical maple syrup urine disease (MSUD) (present ages: 1 3/12, 5 7/12, and 8 11/12 years) are described. Each diagnosis was made by clinical signs rather than by newborn screening. Acute-phase treatment beginning on the 11th day of life comprised peritoneal dialysis, intravenous lipid, and early intestinal alimentation. Mean age at discharge from hospital was 29 days. There were 16 readmissions to the hospital for the group (89 days, 1.05% treatment days) without any serious neurologic symptoms. The mean level of plasma leucine for the group (for levels below 1 mM) during treatment was 0.42 mM (normal for age range, 0.077 +/- 0.021 mM [mean +/- SD]). Plasma leucine exceeded 1 mM during 1.02% of treatment days (representing 8.6% of 1,042 measurements. Mean levels of plasma valine and isoleucine were 60% and 70% of the plasma leucine value for the group. Tolerance for dietary leucine did not exceed 620 mg/day in any patient. Somatic growth was normal and the mean current IQ/development quotient (DQ) score is 101 (range 89 to 117); the three oldest patients attend regular schools. A characteristic EEG pattern resembling the teeth of a comb was observed in three patients during the acute phase in the newborn period but not during long-term treatment. These results were obtained in an ambulatory program with home visiting.

Child↗
PubMed1979

Observations on the composition of milk-substitute products for treatment of inborn errors of amino acid metabolism. Comparisons with human milk. A proposal to rationalize nutrient content of treatment products.

We tabulated and compared the stated compositions of four milk-substitute products, now in wide use for the treatment of various inborn errors of amino acid metabolism, and the known composition of human milk. Variations between the treatment products is great not only in the content of amino acids but also in minerals and vitamins, for example. Different source materials and rationales for their manufacture appear to explain these differences. All four products deviate in many ways from the composition of human milk. Although the existing treatment products are quite effective clinically, we propose that a more rational approach to the feeding of young infants whose nutrition is compromised by inborn errors of metabolism would begin with a synthetic product based on the composition of human milk that could be modified specifically to fit the needs and tolerance of the individual patient.

Amino Acid Metabolism, Inborn Errors↗
PubMed1978

Genetics and Medicine: an evolving relationship.

The rapid expansion of knowledge in human and medical genetics has revealed at least 6 percent average heterozygosity per structural gene locus, in excess of 2300 Mendelian (single gene) variants and several hundred chromosomal variants in man. This means that with the exception of monozygous twins, no two individuals are alike in their phenotype. Therefore, each person has a relative state of health, and genetic factors contribute significantly to disease. The ubiquity of genetic diversity requires the development of services for genetic screening, diagnosis, and counseling to prevent and treat a major portion of disease in modern society. Specific programs in Quebec and Canada illustrate how individuals and populations can be served by such services. Better education of citizens and health professionals in human genetics is essential for the further improvement of genetics services in society.

Blood Chemical Analysis↗
PubMed1977

Knowledge about and attitudes toward genetic screening among high-school students: the Tay-Sachs experience.

High school students (ages 15 to 18 years; No. = 930) taking biology in their curriculum were surveyed (the first survey), in the classroom, for their knowledge and attitudes about Tay-Sachs disease and other "public" issues in genetics. High-school students now constitute 38.9% of those screened for the Tay-Sachs gene in the Montreal program and the participation rate is 75% among eligible Jewish students. Knowledge and attitudes about the screening experience were also surveyed (the second survey) in a sample (No. = 120) containing equal numbers of carriers and noncarriers matched for sex and age. The response rate was 75% in the second survey. The first survey revealed that the level of knowledge about Tay-Sachs disease is high among students, only 28% percent of whom were Jewish. Students have a very positive attitude toward genetic screening in general. These findings are associated with an effort to expand the human genetics content in the biology curriculum. The second survey revealed a favorable attitude toward the screening experience and the self-knowledge obtained among screened students. The screening clinic in the schools, and literature provided by the screening authority, was an effective source of knowledge about the significance of Tay-Sachs heterozygosity. Carriers experienced initial anxiety; later attitudes were similar in carrier and noncarriers. Self-image was unchanged in 90% and diminished in 10% of carriers and enhanced in 10% of noncarriers. Heterozygous students perceive information about their genetic status as useful to themselves and 95% want to know the gennotype of an intended spouse; 88.4% would marry a carrier and only 11.6% would "reconsider." These findings encourage us to emphasise high-school screening as the preferred program in our community and to offer it as an effective aid to the physician faced with increasing demands in medical genetics. It is also an effective model for teaching some genetics and human biology in the schools.

Adolescent↗
PubMed1975

Neonatal hypertyrosinemia and evidence for deficiency of ascorbic acid in Arctic and subarctic peoples.

Hypertyrosinemia tyrosine concentration in whole blood greater than 0.42 mmol/l or 7.5 mg/dl is prevalent among lnuit newborn of the Canadian Eastern Arctic. The rate was 14.8 per 100 newborn between January 1970 and December 1972 (first survey period) and 6.2/100 between January 1973 and September 1974 (second survey period); the corresponding rates among Indian newborn of Nouveau Quebec were 2.6 and 2.2%. Among Anglo-Saxons the rate was less than 0.5% and in French Canada it commonly exceeded 0.94%. Serum concentrations of ascorbic acid were low (less than or equal to 0.25 mg/dl) in the pregnant and age-matched adult lnuit when measured by Nutrition Canada during the first survey period. The percentages of inuit children (up to 4 years old) and pregnant women at "high risk" for scurvy (serum concentration of ascorbic acid less than 0.2 mg/dl) were 14.8 and 47.1, respectively; the corresponding national percentages were 3.0 and 2.2, respectively. Deficiency of ascorbic acid in pregnant women is probably the cause of the unusual prevalence of neonatal hypertyrosinemia among the native Arctic and subarctic peoples because ascorbic acid is required to maintain optimal activity of p-hydroxyphenylpyruvic acid hydroxylase and to permit normal oxidation of tyrosine.

Adolescent↗