Plasma exchange in myasthenia gravis.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to P M Coates.
Explore the source record for details and available documents.
In the resting state, 3T3-L1 fibroblasts become adipose converted and increase their fatty acid and triglyceride synthetase. We have found that they contain four times the neutral lipase activity and 1.5 times the acid lipase activity of logarithmically dividing cells. The activities of lysosomal acid beta-galactosidase and N-acetyl-beta-D-glucosaminidase were the same in the adipose converted and logarithmically dividing cells. The data suggest a possible relation between the increased neutral lipase activity in 3T3-L1 cells and their adipose conversion and demonstrates that the adipose converted 3T3-L1 fibroblasts, unlike true adipose cells, contain high levels of lysosomal acid hydrolases.
A butyryl esterase, designated B4, has been purified from human liver and some of its properties described. The activity of this enzyme comprises 0.48% of the total butyryl esterase activity found in human liver. Esterase B4 has been distinguished from other butyryl esterases by its preference for the esters of the fluorogenic compounds 4-methyl umbilliferone and fluorescein over naphthyl esters as substrates. Other distinguishing features of this esterase include a relatively high pI (pH 8.7) A monomeric structure of low molecular weight (20 000) and high solubility in solutions of ammonium sulphate.
Lysosomal acid lipase (LAL) activity was measured using a new fluorometric assay in cultured skin fibroblasts from eight control subjects, two obligate heterozygotes for Wolman's disease (WD), one patient with WD, and one patient with cholesteryl ester storage disease (CESD). The LAL activities (mean+/-SD) were 25.8+/-8.2, 13.2+/-0.1,1.1, and 1.4 nmol 4-methylumbelliferyl oleate (4-MUO) hydrolyzed/min/mg protein, respectively. These results compare favorably with those obtained using standard radioassays. The LAL activities of two cultures of amniotic fluid cells were 12.1 and 10.5. The LAL activity (mean+/-SD) of peripheral leukocytes obtained from 34 laboratory volunteers (19 females, 15 males) was 4.0+/-1.8. Partially purified lymphocytes contained about 25 times as much LAL activity as did granulocytes. Cellogel electrophoresis, followed by staining with 4-MUO, showed at least two bands of LAL (A and B) from normal fibroblasts, amniotic fluid cells, and lymphocytes. Band A was absent from WD and CESD fibroblasts and was reduced in fibroblasts of the WD heterozygotes.
1. The esterase isozymes of human tissues have been investigated using the technique of starch-gel electrophoresis. Conventional naphthyl-azo dye linked stains and new fluorogenic staining methods were used to detect the isozymes. 2. Multiple isozymes were identified in every tissue and they were characterized in terms of their electrophoretic mobility, tissue distribution, developmental changes in utero, substrate specificity, inhibition properties and molecular weight. On these criteria 13 sets of esterase isozymes were identified, in addition to the esterase isozymes due to cholinesterase and carbonic anhydrase. 3. The data suggest that the 13 sets of isozymes are determined by at least nine different structural gene loci. 4. No electrophoretic variants were identified in a limited population survey of post-mortem tissues from adults and foetuses, except for the previously described esterase D (ESD) phenotypes.
A method for solubilization of human erythrocyte membranes was developed and used to survey 70 unselected human blood samples for isozymic variation of stromal acetylcholinesterase. Three variants were observed. Pedigrees of families studied by this method indicated that this variation represented the phenotypic expression of two codominant alleles at a single locus.
The clinical and pathologic findings in 12 patients with medium-chain acyl CoA dehydrogenase deficiency and three patients with long-chain acyl CoA dehydrogenase deficiency are summarized. Although these inborn errors of intramitochondrial beta-oxidation of fatty acids present with similar findings to Reye's syndrome, there are clinical, laboratory and hepatic histologic differences. Younger age at presentation, history of unexplained sibling death, a previous episode of lethargy, hypoglycemia or acidosis precipitated by fasting stress and only mildly elevated serum transaminases with normal or only mildly prolonged prothrombin time may all suggest an acyl CoA dehydrogenase deficiency. Long-chain acyl CoA dehydrogenase deficiency is differentiated from medium-chain acyl CoA dehydrogenase deficiency by younger age at presentation, more profound cardiorespiratory depression, evidence of cardiomyopathy, and sequelae of muscle weakness, hypotonia and developmental delay. Definitive diagnosis is made by assay of medium-chain or long-chain enzyme activity in cultured skin fibroblasts or in leukocytes. Hepatic light microscopic alterations are essentially limited to steatosis, which may be either macro- or microvesicular. The cases with microvesicular steatosis can be differentiated morphologically from Reye's syndrome by electron microscopy, showing the absence of the mitochondrial changes characteristic of Reye's. Four of seven cases of acyl CoA dehydrogenase deficiency showed some variations from normal in the appearance of the hepatocyte mitochondria. The relationship of these variations to the basic metabolic defect(s) remains to be determined.
BACKGROUND: Although there is consensus that prevention of cardiovascular diseases is a worthwhile activity and that these efforts should begin in childhood, some controversies remain about the efficacy and timing of preventive efforts. OBJECTIVE: To differentiate the cardiovascular risk factors that have a potential to respond to environmental and lifestyle modification. METHODS: The sample consisted of 56 monozygotic and 29 same-sex dyzogotic twin pairs, equally distributed by gender with a mean age of 12.62 years. Systolic and diastolic blood pressure, triceps skinfold thickness, body mass, and fasting blood specimens for lipid profiles were collected during home visits. Teachers rated the subjects' Type A behaviors using the Matthews Youth Test for Health. RESULTS: Statistically significant estimates of genetic variance were obtained for cholesterol, triglycerides, high-density lipoprotein cholesterol, systolic and diastolic blood pressure, and body mass index. Compared with the previous phase of this longitudinal study, higher estimates of genetic variance were observed for components of the lipid profile and blood pressure and lower estimates were observed for Type A behavior variables. CONCLUSIONS: Overall, the genetic influence on risk factors was moderate, leading to the conclusion that the potential to modify risk profiles during the transition from childhood to adolescence is substantial. Attitudes, behaviors, and environmental inducements that establish and maintain healthy lifestyles over long period should be the focus of interventions and further research.
With an appropriate protocol for collection, storage, and sample analysis, it should be possible to ensure correct diagnosis of disorders of fatty acid oxidation presenting to the pathologist. Appropriate counseling of affected families will lead to presymptomatic sibling diagnosis of these frequently treatable disorders, which, in turn, can prevent the catastrophic metabolic consequences of the disorders.
Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is an inherited disorder of fatty acid oxidation associated with sudden death in infants and, in its fulminant form(s), a Reye-like syndrome. In an 18-month-old female who died suddenly and unexpectedly, the postmortem diagnosis of MCAD deficiency was made by analysis of organic acids, acylglycines, and acylcarnitines and by analysis of the most common mutation causing MCAD deficiency (A985G) in a sample of heart blood obtained at autopsy and frozen at -20 degrees C for 8 months. The patient was homozygous for A985G and metabolites characteristic of MCAD deficiency were identified. Parents and an older sibling were heterozygous for A985G. The mother was 6 months pregnant when the results were known. At the birth of her male infant, blood spot cards and urine were obtained. The infant was homozygous for A985G by analysis of DNA extracted from blood spots and he excreted metabolites characteristic of MCAD deficiency. These results demonstrate the use of novel molecular and metabolite analysis in making the postmortem diagnosis of MCAD deficiency. The neonatal diagnosis of an affected sib permits the institution of appropriate dietary measures to prevent potentially fatal episodes of illness.
The heritability of Type A behavior and other cardiovascular risk factors was investigated in twin school-age children. The purpose was to differentiate those risk factors that have the potential to respond to environmental and life-style changes. The sample consisted of 71 monozygotic and 34 same-sex, dizygotic twin pairs 6 to 11 years old residing in the Philadelphia metropolitan area. Systolic and diastolic blood pressure, triceps skinfold thickness, body mass, and fasting blood specimens for lipid profiles were collected during home visits. Teachers rated the children's Type A behavior and two of its subcomponents, impatience-aggression and competitive achievement-striving, using the Matthews Youth Test for Health. Statistically significant heritability estimates were found for Type A behavior and its subcomponents, triglycerides, systolic blood pressure, and body mass. Nevertheless, there was substantial environmental influence on these risk factors. The greatest environmental influence was observed for HDL-cholesterol, LDL-cholesterol, apolipoprotein-B and diastolic blood pressure.
The relationship of Type A behavior pattern (TABP) and its components to physiological cardiovascular disease (CVD) risk factors of blood pressure, obesity, and lipids and lipoproteins was examined in 112 pairs of twin children. Blood pressure, triceps skinfold thickness, and fasting venous specimens for lipid profiles were collected during a home visit. Teachers rated children's Type A-B behaviors using the Matthews Youth Test for Health (MYTH) (Matthews & Angulo, 1980). For statistical analyses, one member of each twin pair was assigned to Group I and the co-twin to Group II. In Groups I and II, significant, p less than or equal to .01, negative correlations between the impatience-aggression component of TABP and atherogenic lipids were observed before and after covariate adjustments. Children were classified as MYTH Type A or B on the basis of a median-split. Marginally significant differences (B greater than A) were found between the mean lipid levels of Type A and Type B children. No significant A-B differences in blood pressure or measures of obesity were observed in either group. Multivariate analysis of variance results suggested that lipid profiles in Group I differed significantly, p less than or equal to .02, by Type A-B classification. The results of this study suggest that TABP and its components are not positively associated with physiological risk factors for CVD; and the impatience-aggression component of TABP is associated with lower levels of atherogenic lipids.
Matched-pair analyses of twins were used to examine nongenetic influences of obesity on the lipid profile and systolic and diastolic blood pressure (cross-sectionally) during two phases of development--the school-age years (n = 73 twin pairs) and adolescence (n = 56 twin pairs)--and (longitudinally) in the transition between these two developmental phases. Data were collected during an early morning home visit. Results of the matched-pair t tests indicated significant environmental influences on obesity in both phases and in the transition (change in obesity) between these two phases. Intraindividual associations of obesity (kg/m3) and atherogenic lipids (total and LDL cholesterol) emerged during the school-age years. In adolescence, obesity was associated with HDL cholesterol and total triglyceride. Change in obesity (kg/m3) from the school-age years to adolescence was associated with total triglyceride. Results suggest an emphasis on obesity as part of CVD risk factor management in children and point to the importance of primary prevention early in life.