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Biomedical subjects

J A Morrison

Publications and source records attributed to J A Morrison.

143 records · Page 8Linked to original sources
PubMed1975

The management of radioactive wastes resulting from emergency situations on land and sea.

The term 'emergency' applies to unplanned events that have generated, or had the potential to generate, radioactive wastes that could not be handled locally. Reports of past emergencies form the basis for discussion of future trends in emergency situations, the factors that influence waste management, the technology of waste management and personnel requirements. The number of past emergencies has been small and these have not increased the volume of radioactive wastes significantly. The majority of future emergencies are likely to be associated with reactors as they have been in the past. Little change in the nature of the waste is expected, although the greater use of separated plutonium may create some new problems. The factors that influence emergency waste management fall into two categories, those that are concerned with the location of the emergency event, and those concerned with the characteristics of the wastes. As in the past, it can be expected that in most emergencies proven waste management techniques will be adapted to suit the local circumstances but there is a need for simpler and more economic methods. Trained personnel and comprehensive planning are cited as key factors in successful waste management operations.

Accidents↗
PubMed1974

Analysis of alpha-lipoprotein cholesterol in 50 microl of plasma.

A micromethod for quantitation of alpha-lipoprotein cholesterol was devised for gas-liquid chromatography to minimize plasma sample size and facilitate lipid studies using capillary blood from children or small animals. alpha-Lipoprotein cholesterol was measured by gas-liquid chromatography in 20 micro l of the centrifuged supernate obtained after addition of 5 micro l of mixed heparin-manganese chloride solution 1:1 (v/v) to 50 micro l of plasma. Comparison of venous alpha-lipoprotein cholesterol measured by gas-liquid chromatography with venous alpha-lipoprotein cholesterol measured by conventional heparin-manganese precipitation and ferric chloride (colorimetric) cholesterol determination gave a correlation coefficient of 0.98 for 80 plasma samples. Capillary alpha-lipoprotein cholesterol and venous alpha-lipoprotein cholesterol were closely correlated in 31 patients (r = 0.97).

Adult↗
PubMed1974

Quantitative analysis of cholesterol in 5 to 20 microliter of plasma.

A gas-liquid chromatographic micromethod for quantitation of cholesterol in 20 micro l of plasma was developed using 5alpha-cholestane as an internal standard, saponification with tetramethylammonium hydroxide-isopropanol, and extraction with tetrachloroethylene-methyl butyrate. Cholesterol levels in plasma samples were calculated by comparing cholesterol-cholestane peak height ratios with those of preassayed reference plasma. Over a plasma cholesterol range of 44 to 468 mg/100 ml, the gas-liquid chromatographic micromethod and the automated ferric chloride colorimetric method gave nearly identical results (r = 0.99) in duplicate aliquots of 131 plasma samples.

Adult↗
PubMedDate not supplied

Assessing the body composition of 6-17-year-old Black and White girls in field studies.

The purpose of the study was to develop ethnic-specific equations for fat-free mass (FFM) from selected anthropometric dimensions and bioelectrical impedance measures of resistance (R) and reactance (Xc) for use in the NHLBI Growth and Heath Study. Using dual-energy X-ray absorptiometry measures of body composition as the dependent variable and field measures of body composition by anthropometry and bioelectrical impedance as the explanatory variables, ethnic-specific prediction equations were developed on a sample of girls representing a wide range of ages and BMI. The equations were cross-validated using (1) the Prediction of Sum of Squares (PRESS) statistic and (2) an independent sample of 20 girls of each race from a study conducted at the National Institute of Child Health and Human Development (NICHD). Subjects were 65 White and 61 Black girls 6-17 years of age. The best race-specific equations for FFM each explained 99% and 97% of the variance in the White and Black girls, respectively. Root mean square errors (RMSE) ranged from 1.14 to 1.95 kg. The equation for Black girls used Stature2/Resistance (R), weight, and reactance (Xc) as predictor variables; the equation for White girls used Stature2/R, weight, and triceps skinfold thickness. The results indicate that (1) equations to predict FFM in girls should be ethnic-specific and that (2) accurate values for TBF and %BF can be calculated from the predicted FFM.

Adolescent↗
PubMedDate not supplied

Studies of blood pressure in hyperlipidemic school children.

To assess determinants of blood pressure and racial differences in blood pressure in hyperlipidemic children, and to compare blood pressure in hyperlipidemic and random recall groups of children, studies were carried out on 513 school children (ages 6 through 19 years), and 309 adults (ages 20 through 64), recalled by virtue of elevated cholesterol or triglyceride levels in the Cincinnati Lipid Research Clinic's Princeton School prevalence study. For systolic and diastolic blood pressure in children, there were positive simple correlations with plasma triglyceride and inverse correlations with plasma high density lipoprotein cholesterol. Race did not enter the multiple regression equations as a significant explanatory variable for children's systolic or diastolic blood pressures, but was a significant variable for adults' blood pressures; blacks had higher pressures. Major explanatory variables for systolic blood pressure in children included weight, pulse, and age; 46% of the variance was explained. Major variables for diastolic blood pressure in children included age, pulse, and Quetelet index; 25% of the variance was explained. After covariance adjusting for Quetelet index, blood pressures within race did not differ between the hyperlipidemic and the random recall groups. Quetelet index was the covariable that related positively to blood pressure and plasma triglycerides, and negatively to high density lipoprotein cholesterol. Although relative ponderosity does not appear to be an independent coronary heart disease risk factor variable, its inverse relationship to high density lipoprotein cholesterol and positive association with triglyceride and blood pressure in school children should provide a basis for prudent, early, therapeutic approaches to overweight children and those with persistently elevated blood pressure. (Arteriosclerosis 1981; 1:280-286).

Age Factors↗
PubMedDate not supplied

Familial associations of lipids and lipoproteins in families of hypercholesterolemic probands.

We used the Princeton School Family Study hypercholesterolemic recall group to assess whether, and to what degree, the identification of hypercholesterolemic subjects could be improved through the phenomenon of familial lipid and lipoprotein aggregation. A second aim was to assess whether within-family lipid and lipoprotein correlations outlasted the period of shared family environment. Approximately twice as many (as expected) siblings and offspring of hypercholesterolemic probands had plasma total and low density lipoprotein cholesterol levels greater than the 90th and 75th percentiles respectively, emphasizing how identification of hypercholesterolemic subjects can be facilitated by use of the phenomenon of familial aggregation of plasma total and low density lipoprotein cholesterol. After exclusion of the hypercholesterolemic probands from calculations of within-family correlations, and use of natural log transformations for the probands' first-degree relatives' lipids as required, most father/pediatric offspring and mother/pediatric offspring correlations for lipids and lipoprotein cholesterols were significant, while most parent/adult offspring correlations were not significant. All pediatric sibling correlations for lipids and lipoprotein cholesterols were significant; most adult sibling correlations were not significant. The loss of significance and consistency in sibling and parent/offspring lipid and lipoprotein correlations in adults who no longer shared a common household environment points to environmental influences on total, high, and low density lipoprotein cholesterol in kindreds with a hypercholesterolemic proband.

Adult↗
PubMedDate not supplied

Relationships of nutrient intake to lipids and lipoproteins in 1234 white children. The Lipid Research Clinics Prevalence Study.

Using the geographically and socioeconomically varied collaborative Lipid Research Clinics Prevalence Study data, this report focuses upon relationships between dietary intake and plasma lipids and lipoproteins in 1234 white children, 661 boys and 573 girls, aged 6-19 years who were sampled in a random recall (Visit 2) from large populations in six Lipid Research Clinics. Using multiple regression analysis, we found that in 6- to 12-year-old boys the dietary polyunsaturated-to-saturated fat ratio was inversely associated with plasma total and low density lipoprotein cholesterol and dietary cholesterol was positively associated with plasma high density lipoprotein cholesterol. In 13- to 19-year-old boys, high density lipoprotein cholesterol and the ratio of high density lipoprotein cholesterol to total cholesterol were inversely related to sucrose intake. In 6- to 12-year-old girls, plasma triglycerides were positively related to dietary sucrose. Using analysis of covariance in children having the lowest, middle, and top decile nutrient intakes, we found that higher carbohydrate intakes were associated with lower plasma total cholesterol in boys. The highest polyunsaturated fat intake (in 6- to 12-year-old girls) was associated with the lowest plasma cholesterol and very low density lipoprotein cholesterol. The highest cholesterol intake (in 6- to 12-year-old boys) was associated with the highest high density lipoprotein cholesterol levels. In girls, the highest sucrose intakes were associated with the highest plasma triglyceride levels. We conclude that the weak, but statistically significant, associations that we observed were meaningful relative to etiologies of nutrient-lipoprotein interrelationships, and should be useful in forming new hypotheses for focused metabolic ward studies.

Adolescent↗
PubMedDate not supplied

Family aggregation of high density lipoprotein cholesterol. Collaborative lipid research clinics program family study.

High density lipoprotein cholesterol data on a population-based random sample of 858 white and 72 black probands and their 3935 white and 205 black relatives were collected from nine North American clinics using a common protocol and standardized methodology. Familial associations were examined within clinics for whites and pooled across clinics for blacks. The influence of covariates and varying family size on correlations was examined using several sets of transformed and adjusted values and a variety of weighting schemes. Parent-offspring and sibling correlations were significant in most cases, but spouse correlations were not, suggesting a stronger influence of shared genes than shared environment on high density lipoprotein cholesterol. Adjustment for covariates tended to weaken the correlations, but the effect of variable family size was imperceptible. Although pairs involving pediatric offspring or siblings tended to show higher correlation than their adult counterparts, the differences were not significant. All correlations except father-daughter and brother-brother were homogeneous across clinics in whites. There was no asymmetry in parent-child correlations by the sex of the offspring, but the pooled mother-child correlation was significantly higher than father-child values, suggesting a possible maternal influence on high density lipoprotein cholesterol. No heterogeneity in correlations in high density lipoprotein cholesterol was detected between blacks and whites except for mother-son pairs.

Adolescent↗