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Biomedical subjects

A Clarke

Publications and source records attributed to A Clarke.

At least 253 records · Page 14Linked to original sources
PubMed1987

Genetic control of susceptibility to atherosclerosis (with special emphasis on the role of the macrophage).

The pathogenesis of atherosclerosis involves a complex interplay of arterial endothelium, multiple cellular constituents, and circulating lipo/apolipoproteins. Early work implicated a single etiology--either excess of circulating lipids, disruption of endothelial integrity, or clonal proliferation of smooth muscle cells. However, current research supports a hypothesis unifying endothelial disruption with lipid imbibation. The macrophage is recognized as having an integral role in atherogenesis due to its capacity to adhere to endothelium, internalize and metabolize lipids, and liberate proteases, apolipoproteins, and mitogens. Genetically determined susceptibility or resistance to atherosclerosis has long been described in animals and man, and differences in lipo/apolipoproteins have been proposed to explain these variations. Genetically defined variants of inbred mice have been used to pursue hereditary influences in atherogenesis. Strain variations in lipid metabolism have been advanced as one possibility to explain a polygenic mode of inheritance--those strains most replete in cholesterol-enriched lipoproteins demonstrating the greatest susceptibility. However, there is now a substantial body of evidence suggesting that the diverse functions of the macrophage may be the mechanism underlying the genetic polymorphism in atherosclerosis. Recombinant inbred strains of mice may serve as a vehicle through which this concept can be explored.

Animals↗
PubMed1986

Duodenal delivery of levodopa for on-off fluctuations in parkinsonism: preliminary observations.

The pathogenesis of on-off motor fluctuations in parkinsonism remains incompletely understood, but slowed or erratic gastric emptying of orally administered levodopa may be involved. In 3 patients with resistant on-off fluctuations, direct duodenal continuous infusion of levodopa via a nasoduodenal tube resulted in a heightened therapeutic effect, including a reduction in motor fluctuations. In 1 of these patients, continuous duodenal levodopa infusion produced greater benefit than did intermittent duodenal levodopa administration. Direct duodenal delivery of levodopa lessens the problems with gastric emptying and may be suitable for long-term therapy in selected patients with resistant on-off motor fluctuations.

Adult↗
PubMed1986

Facilitating comprehension of discharge medication in elderly patients.

Provision of adequate information is well established as an important determinant of patient compliance with taking medication. Elderly patients, who constitute a large proportion of patients discharged from hospital on medication, may be particularly at risk of unintentional noncompliance due to inadequate or forgotten information. This study demonstrates that counselling provided to the elderly by a clinical pharmacist significantly improved knowledge about medication and, therefore, the opportunity for compliance at home.

Aged↗
PubMed1986

Use of a medical 'schema' in facilitating access to understanding in psychology.

Cognitive models in psychology suggest that knowledge can only be fully comprehended and recalled within the framework of existing schemata. Two experiments are reported which demonstrate how psychological principles may be taught within the schemata available to preclinical medical students. It is suggested that the provision of appropriate schemata makes psychological knowledge more accessible to medical students, and more easily recalled as they move into clinical practice. Increasing the impact of psychology in this way may also encourage greater interest and integration of the subject in the medical curriculum.

Adult↗
PubMed1986

Duchenne muscular dystrophy with adrenal insufficiency and glycerol kinase deficiency: high resolution cytogenetic analysis with molecular, biochemical, and clinical studies.

A syndrome of Duchenne muscular dystrophy (DMD), adrenal hypoplasia, glycerol kinase deficiency, and mental retardation has been recognised. We report a further case ascertained from a history of DMD, severe mental retardation, and an Addison-like disorder. Cytogenetic analysis of the proband revealed an interstitial deletion of the short arm of the X chromosome. from Xp21.1 to Xp22.11, comprising about 9% of the length of the normal X chromosome. His mother was heterozygous for the deletion, but his maternal grandmother and sister both had two normal X chromosomes. DNA probe analysis confirmed the existence of a deletion in the affected boy, as probes 754, C7, XJ1-1, and pERT87 consistently failed to hybridize to his DNA. His sister was heterozygous for the RFLP associated with 754, thus confirming that she had two normal X chromosomes. There was no evidence of chronic granulomatous disease, other immunological defect, or retinitis pigmentosa in this case. Biochemical studies revealed gross glyceroluria and hyperglycerolaemia, indicating glycerol kinase deficiency which has been confirmed enzymatically. We have subsequently screened 21 other boys with DMD for glyceroluria and found one other case. Cytogenetic analysis has also been performed in nine other families, where a boy with DMD has been shown to have a deletion of DNA sequences localised to the region Xp21. None of these cases demonstrated any cytogenetic abnormality, nor has their clinical course been unusual.

Adolescent↗
PubMed1984

Cholesteryl esters in human gallbladder bile and mucosa.

Cholesteryl esters, identified by thin-layer and gas-liquid chromatography followed by mass spectroscopy in a few cases, were found in all human bile samples analysed. The amount varied extensively both in absolute concentration and when expressed as a percentage of the total cholesterol present. In about 30% of samples, the percentage of ester exceeded 4% of total cholesterol but there was no clear association with the presence of cholesterol gallstones or pigment stones, nor was there any association with the lithogenicity of bile.

Bile↗
PubMed1984

Familial intracranial gliomas.

The pedigree of two interrelated families with 10 affected members suffering from malignant supratentorial gliomas is reported. In addition, three other unrelated families with two members each who were treated for different types of brain tumors are described. Genetic implications are discussed.

Adolescent↗
PubMed1984

Child life intervention in the emergency department.

Since 1979, the Child Life Department of the Children's Hospital of Eastern Ontario has provided 75 hours per week of Child Life intervention for children and parents in the emergency department. Factors that would influence a child's ability to master an emergency experience have been identified through a review of the literature. The protocol for Child Life intervention in frequent emergency situations is described. Practical approaches to Child Life programs in Emergency and evaluation of effects of Child Life intervention are discussed.

Child↗
PubMed1984

Women and the economics of aging.

Economic and policy arrangements assure the maintenance of gender-based inequities throughout the life cycle. To understand the economics of aging requires consideration of the problems of women of all ages, commencing early in the adult life cycle when the different social roles and opportunity structures available to men and women take effect. Because the economic inequities suffered by women in old age derive principally from inequities suffered earlier as wives and workers, public policy focused on redressing income in old age does nothing to alter the structural basis of inequity. This article examines factors underlying the economics of aging for older women in the United States; delineates the relation between women's roles, social policy, and income; and raises salient policy questions for younger and older women.

Aged↗
PubMed1983

Social and exploratory behaviour in the rat after septal administration of ORG 2766 and ACTH4-10.

The time spent in active social interaction by pairs of male rats in a dimly-lit, familiar test arena, was decreased significantly after intraseptal injection of ACTH4-10 (250-500 ng). In contrast, the time spent in active social interaction was increased significantly after intraseptal injection of the tri-substituted ACTH4-9 analogue ORG 2766 (250-500 pg). Neither ACTH4-10 (250 ng) nor ORG 2766 (250 pg) affected exploration or locomotor activity measured in a holeboard, after intraseptal injection. Intraseptally administered ACTH4-10 (250 ng) increased aggression measured in a colony intruder model, but ORG 2766 (250 pg) was without effect.

Adrenocorticotropic Hormone↗
PubMed1983

Morphological, total nucleic acid and total protein analyses of rat embryos cultured in supplemented and unsupplemented human serum.

Culture of explanted 9 1/2 day rat conceptuses for 48 hours (i.e. until 11 1/2 days) in 100% human serum supplemented only with glucose does not result in growth and development comparable to those conceptuses cultured for the same period in 100% rat serum. Significant differences were observed in the yolk sac diameter, crown-rump length, morphological score and total embryonic nucleic acid content. No difference was observed in the total embryonic protein content. A large proportion of the embryos cultured in glucose-supplemented human serum (100%) exhibited abnormalities of the neural tube. Supplementation of the human serum with glucose and 10% rat serum resulted in embryos showing higher indices of embryonic growth and differentiation (in all criteria of assessment) than those cultured in pure rat serum; no abnormalities were observed. The significance of better growth and differentiation of the conceptuses in human serum supplemented with glucose and 10% rat serum is discussed.

Animals↗
PubMed1982

Characterization of glycoprotein antifreeze biosynthesis in isolated hepatocytes from Pagothenia borchgrevinki.

Incorporation of 14C-leucine and 3H-alanine into TCA-precipitable protein. TCA-soluble protein, and antifreeze glycoproteins (AFGP) was measured in isolated hepatocytes from Pagothenia borchgrevinki Boulenger following acclimation to -1.5 degrees C and +4 degrees C. the rate of 3H-alanine incorporation into AFGP followed Michaelis-Menten kinetics with a Vmax of 4.8 nM X mg protein-1 X h-1 at -1.5 degrees C and 7.5 nM X mg protein-1 X h-1 at +4 degrees C. Km values were 27.9 microM and 41.7 microM at -1.5 degrees C and +4 degrees C, respectively. Incorporation of 14C-leucine into TCA-precipitable protein also showed Michaelis-Menten kinetics with a Vmax of 20 nM X mg protein-1 X hr-1 at 1.5 degrees C and 32.3 nM X mg protein-1 X hr-1 at +4 degrees C. Km values were 83.3 microM at -1.5 degrees C and 125 microM at +4 degrees C. AFGP synthesis was monitored over a 120-h period by radioimmunoassay in cultures of hepatocytes from cold acclimated fish (-1.5 degrees C) incubated at both -1.5 degrees C and +4 degrees C. The estimated Q10 for AFGP from these data is 3.23. Polyacrylamide gel electrophoresis of antifreeze glycoproteins produced by isolated hepatocytes showed that all four antifreeze fractions normally present in the serum of P. borchgrevinki are also synthesized by isolated hepatocytes. The two major conclusions from these experiments were that 1) P. brochgrevinki, unlike many northern fishes, does not show thermal acclimation, and 2) environmental factors responsible for modification of peptide antifreeze synthesis in northern fishes do not elicit changes in AFGP synthesis in P. borchgrevinki.

Acclimatization↗
PubMed1982

Selective neurotoxin lesions of the lateral septum: changes in social and aggressive behaviours.

Bilateral microinjection of 5,7-dihydroxytryptamine into the lateral septum resulted in a behavioural profile in the Social Interaction test of anxiety similar to that seen after chronically-administered benzodiazepines. In contrast, bilateral microinjection of 6-hydroxydopamine into this locus did not alter the profile of rats tested in this model. In a colony-intruder model of aggression, the 5,7-dihydroxytryptamine lesioned rats showed decreased dominance, while the 6-hydroxydopamine lesioned rats showed increased dominance and reduced subordination. The results suggest that lateral septal 5-hydroxytryptamine, but not catecholamines, is important in the control of anxiety, whereas both lateral septal 5-hydroxytryptamine and catecholamines are involved in the control of aggression.

5,7-Dihydroxytryptamine↗