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Biomedical subjects

M Adamson

Publications and source records attributed to M Adamson.

18 recordsLinked to original sources

Indian childhood cirrhosis in an American child.

Indian childhood cirrhosis is a fatal liver disease characterized by a striking accumulation of copper-containing granules within hepatocytes. A two-year-old American boy, the product of a third-cousin marriage, with clinical, biochemical, and histological signs of Indian childhood cirrhosis was studied. Liver biopsies at 22 and 30 months of age revealed a rapid progression from fibrosis to micronodular cirrhosis, with many of the remaining hepatocytes staining strongly for copper and copper-binding proteins. Electron microscopy showed characteristic dense granules containing copper and sulfur by electron probe analysis. Hepatic copper content was 1500 micrograms/g dry weight (normal, 20-50). Urinary copper was 3.6 mumol/d (229 micrograms/24 hours; normal, 15-20), and serum ceruloplasmin was 352 mg/L (normal, 150-320). The case suggests that both genetic and environmental components contribute to the manifestations of Indian childhood cirrhosis, and that the diagnosis of Indian childhood cirrhosis should be considered even in non-Indian infants with progressive liver disease.

Copper

The relationship of age, gender, and exercise practices to measures of health, life-style, and self-esteem.

A study of 478 adults from a rural-urban region was conducted to determine differences in health and life-style measures based on age, gender, and exercise involvement that would provide data to incorporate in healthy-living programs. Pender's Health Promotion Model provided the framework for the study. Significant results related to age, gender, exercise, and initiation and maintenance of health-promoting practices were found.

Adolescent

Absence seizures in children: clinical and electroencephalographic features.

The clinical and electroencephalographic (EEG) features of absence seizures in children were evaluated using EEG frequency modulation radiotelemetry and videotape monitoring. The only seizures evaluated were those with a spike-and-wave or multiple spike-and-wave duration lasting at least 3 seconds. A total of 926 absence seizures (426 typical, 500 atypical) were reviewed in 54 patients. Abnormal interictal EEGs, multiple seizure types, mental retardation, or developmental delay were more likely in patients with atypical absence seizures than in patients with typical absence seizures. Both types of absence seizures usually had a clear onset and cessation. Atypical absence seizures lasted significantly longer than did typical absence seizures. Automatisms occurred more frequently in typical absence seizures than in atypical ones, while decreases in postural tone or tonic activity occurred more frequently in atypical absence seizures. Receptive and expressive speech were retained in some patients during both types of seizures. This study demonstrates that typical and atypical absence seizures are not discrete entities but rather form a continuum. No single clinical feature can adequately distinguish the two seizure types.

Adolescent

Polygraphic studies.

Polygraphic recordings have provided new information about the wide ranges of normality in various diseases and the process of maturation from birth to childhood. New techniques will help to document clinical events accurately, improve diagnosis, and evaluate treatment.

Child

Biochemical phenotyping of a single sibship with both cystinosis and Fabry disease.

Two lysosomal storage diseases, cystinosis and Fabry disease, were diagnosed clinically in different members of a single sibship. The possibility that the affected sister and brother might have related disorders with disparate manifestations was pursued. The four principal family members were tested for heterozygote status with respect to serum and leukocyte alpha-galactosidase A activity, urinary trihexosylceramide excretion, and the capacity to engage in cystine counter-transport across leukocyte lysosome membranes. Results were consistent with classical autosomal recessive inheritance in the case of cystinosis and X-linked inheritance for Fabry disease, confirming that this family represents an example of two rare disorders occurring in the same sibship.

Adolescent

[Survey on Schistosomes of man and livestock in Senegal using specific identification given by chetotaxy of cercaria. I. New arguments for the validation of S. curassoni Brumpt, 1931, parasite of man and domestic Bovidae].

Study of Senegal cercariae emitted by naturally infected snails or by snails experimentally infected using eggs from human urine or from sheep liver, and study of the corresponding eggs. The relative position of the dorsal sensillae of cercariae is described by an "AD index" and the ratio length/width of eggs by an "L/l index." At the present time, we have not finished the epidemiological studies, certain experiments are imperfect and the isoenzyme analysis of the corresponding adults is incomplete. Nevertheless information given by the indices AD and L/l agree and lead us to admit the existence of a Schistosome different to mattheei, haematobium and bovis and which, following Brumpt and Gretillat we refer to as Schistosoma curassoni. If one relies on the indices, the study indicates that: a) S. mattheei has not been found in Senegal, b) S. bovis is quite rare, c) S. haematobium apparently exists in pure infections in Casamance and in mixed infections with S. curassoni in man in the north and in the east, d) S. curassoni is apparently the dominant species in domestic ruminants and in man in the north and in the east, e) Bulinus umbilicatus is the principal vector of S. curassoni and S. haematobium.

Animals

The fracture toughness (KIC) of amalgam.

The fracture toughness (KIC) has been measured (at 1 week) for a selection of sixteen amalgam products. This included low copper (i.e. Cu less than 6%) and high copper (both single component and admixed) products in milled and spherical powder forms. The results have shown that the fracture toughness decreases progressively as the copper content increases. The admixed high copper products possess superior fracture toughness to those containing a single component powder. These results have been attributed to differences in the microstructures produced by changes in composition and form in which the copper addition is made.

Copper

Lactoperoxidase binding to streptococci.

There have been conflicting reports regarding the binding of lactoperoxidase to bacterial cell surfaces. We describe here the effects of cell-bound lactoperoxidase on acid production by suspensions of Streptococcus mutans (NCTC 10449) in the presence of hydrogen peroxide and thiocyanate. Saline suspensions of log-phase bacteria were treated with 0.1 mg of lactoperoxidase per ml and were then washed thoroughly. The addition of hydrogen peroxide and thiocyanate markedly reduced the acid production of these lactoperoxidase-treated bacteria but had no effect on the acid production of untreated controls. After a 3-h incubation in saline, the lactoperoxidase-treated bacteria produced acid in the presence of hydrogen peroxide and thiocyanate at the same rate as untreated bacteria. These observations suggest that lactoperoxidase is initially bound to the cell surface in an enzymatically active form at a concentration sufficient to inhibit acid production. The lactoperoxidase is slowly degraded or desorbed as the bacteria stand in saline suspension.

Cell Membrane

Enzyme activity of salivary lactoperoxidase adsorbed to human enamel.

Human saliva was incubated with human enamel powder, and the lactoperoxidase activity of the saliva was measured before and after incubation. Liquidphase lactoperoxidase activity was reduced in direct proportion to the weight of enamel powder added. Lactoperoxidase molecules were adsorbed to the enamel surface in an enzymatically active conformation, and this enamel-bound lactoperoxidase activity was also measured. The adsorption of lactoperoxidase was irreversible and produced at least a 40% increase in the concentration of lactoperoxidase in the enamel surface phase as compared with its concentration in the liquid phase. Enamel-bound lactoperoxidase, as well as the free enzyme, was capable of inactivating the key glycolytic enzyme hexokinase. The implications of the adsorption phenomenon for bacterial colonization are discussed.

Adsorption

Foetal breathing.

This article looks at the current thinking about foetal breathing. Initially, animal studies are discussed and factors affecting foetal breathing defined. These studies are then correlated with preliminary human foetal studies, leading to the possible role that breathing movements may play in defining hypoxaemia in the foetus a risk.

Anesthesia