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Biomedical subjects

J Pearce

Publications and source records attributed to J Pearce.

At least 73 records · Page 4Linked to original sources

The group of hypotonic schizophrenics.

The physical and psychological characteristics of hypotonic schizophrenic children are described. It is hypothesized that hypotonic schizophrenia constitutes a homogeneous subgroup within the schizophrenic spectrum. The criteria for diagnosing hypotonic schizophrenia are stated. By selecting a homogeneous subgroup of schizophrenic patients, investigators may improve the probability of identifying a common biochemical etiology within this subgroup.

Autistic Disorder

Presynaptic dense bars at neuromuscular synapses of the lobster, homarus americanus.

The three dimensional ultrastructure of presynaptic dense bars was examined by serial section electron microscopy in the excitatory neuromuscular synapses of the accessory flexor muscle in the limbs of larval, juvenile, and adult lobsters. The cross-sectional profile of the dense bar resembles an asymmetric hourglass, the part contacting the presynaptic membrane being larger than that projecting into the terminal. The bar has a height of 55-65 nm and varies in length from 75-600 nm. In its dimensions it resembles the dense projections in the synapses of the CNS of insects and vertebrates. The usual location of these dense bars is at well defined synapses, though a few are found at extrasynaptic sites either in the axon or terminal. In the latter case the bars are close to synapse-bearing regions, particularly in the larval terminals, suggesting that the extrasynaptic bars denote early events in synapse formation, In all cases the bars are intimately associated with electron lucent, synaptic vesicles located on either side, in the indentation of its hourglass-shaped cross sectional profile. The vesicles occur along the length of the bar and contact the presynaptic membrane. Consequently the dense bar may serve to align the vesicles at the presynaptic membrane prior to exocytosis. A similar role has been suggested for the presynaptic dense bodies at the neuromuscular junction of the frog, where synaptic vesicles form a row on either side of this structure.

Animals

The response of liver enzymes to feed restriction and subsequent ad lib. feeding in the laying hen.

1. The effects of restricted feeding, and ad lib. feeding following food restriction, on hepatic carbohydrate and lipid metabolism in the laying hen were studied. 2. The birds were allocated to four groups and given either 92, 84 or 75 g/d or allowed ad lib. access to food. 3. Food restriction significantly reduced liver total lipid content compared with ad lib.-fed control birds and this was reflected in reduced hepatic lipogenic enzyme activities. 4. When birds from the restricted regimens were allowed free access to food they initially consumed more food than the control group but after 2 weeks of ad lib. feeding the food consumptions of the birds in all the groups were similar. 5. Concomitant with the increase in food intake there were also increases in liver lipid content and hepatic lipogenic enzyme activities. After 18 d of ad lib. feeding these measurements were similar in the previously restricted birds and the ad lib.-fed control group. 6. Despite these effects on lipid metabolism, food restrictio, and the subsequent release from food restriction, had no significant effects on the specific activities of the glycolytic enzymes examined. 7. Although there were large increases in liver lipid content following release from feed restriction no birds died from, or showed any of the symptoms of, fatty liver-haemorrhagic syndrome. This suggests that, in the absence of any other factor which may be involved in the syndrome, these high liver lipid contents were not, alone, sufficient to cause FLHS. The results also indicate that free access to food following food restriction is unlikely to be a major factor in initiating the syndrome.

Animals

The effects of diet on some hepatic enzyme activities in the pre-ruminant and ruminating calf.

Three mild-replacer diets containing different amounts of lipid with differing fatty acid compositions were fed to pre-ruminant calves. These diets did not affect the specific activities of the hepatic enzymes, involved in carbohydrate and lipid metabolism, which were studied. With the onset of rumination there was a general decrease in the activities of the glycolytic enzymes and glucose-6-phosphate dehydrogenase (EC 1.1.1.43) and an increase in the activity of acetyl CoA synthetase (EC 6.2.1.1). In the ruminating calf the specific activities of some of the enzymes of carbohydrate metabolism were substantially greater on the concentrate diet than on the pelleted dried grass. In the case of glucose-6-phosphate dehydrogenase, this difference attained statistical significance. This may be related to the amount of glucose absorbed as such from the small intestine in animals on the different diets.

Animal Feed

The influence of sex, age and strain of chicken on liver biotin content.

Liver biotin concentrations were substantially lower in 2 to 4-week old broilers than in similarly aged layer-type chicks. Liver biotin concentrations plateauxed at 3 weeks of age. No consistent effect of sex was observed on liver biotin concentrations. The results are discussed in terms of susceptibility to biotin deficiency and fatty liver and kidney syndrome.

Aging

Lactate administration and fatty liver and kidney syndrome development in biotin-deficient chicks.

Two experiments were carried out to determine whether administration of lactate to biotin-deficient chicks induced fatty liver and kidney syndrome (FLKS). 2. The results suggest that increased serum lactate concentrations are a consequence of the syndrome rather than a contributory factor in its incidence. 3. The increase in liver lipids of birds affected by FLKS was not associated with an increase in the specific activity of the hepatic lipogenic enzyme acetyl CoA carboxylase accept when birds developed FLKS spontaneously in experiment 2. 4. Some biotin-deficient chicks did not show physical symptoms of deficiency although mean liver biotin concentrations were low (0.31 microgram/g liver).

Acetyl-CoA Carboxylase

Values education: extending the view.

A number of values education strategies have recently been developed for use in the classroom. The Shaver model described here incorporates a rational decision-making process based on basic moral values. That process involves identifying and clarifying values, value labeling and generalization, examining the possible consequences of value decision, recognizing and resolving value conflict, and forming qualified decisions. It is not, however, necessary to proceed through that exact sequence of steps. For example, values discussion may begin with the teacher helping a students to recognize a value conflict. From that point, the discussion may move the identification and labeling of values. Consequently, there is flexibility in how this model may be used in the classroom. This model is developed on the premise that people who use such a process in making decisions relating to social-ethnical issues enhance their functioning within a democratic society. It is suggested that people who utilize this process in relation to health issues can likewise enhance the effectiveness of their health-related decisions. Hopefully, there will be a yield of postive health behaviors.

Child

Biotin deficiency and liver metabolism in relation to fatty liver and kidney syndrome.

Varying degrees of biotin deficiency were induced by adding freeze-dried, raw egg white to the diet of broiler chicks. Aspects of liver metabolism were studied with reference to fatty liver and kidney syndrome. Mortality was low with 11.8 g egg white/kg diet, or less, but with 17.7 g/kg or more, mortality was very high. High mortality was observed with less than 0.33 microgram biotin/g liver. Associated with low concentrations of liver biotin were substantial increases in liver weight and lipid content in starved birds. The increased liver lipid content was not observed in birds fed ad libitum. The increased liver lipid content in biotin-deficient, starved birds was not reflected in the specific activities of hepatic lipogenic enzymes or hepatic lipogenesis in vivo measured by the incorporation of tritium from 3H-labelled water into liver lipid. Biotin deficiency affected the specific activities of the biotin-requiring enzymes, pyruvate carboxylase and acetyl CoA carboxylase, differently; the latter was unaffected whereas the former decreased concomitantly with liver biotin concentration.

Animals

Symptomatic Parkinsonism.

Parkinson's disease, 'paralysis agitans', is characterized by a number of abnormalities. A similar clinical picture may be symptomatic of other disturbances: these are briefly described and the differential diagnosis is discussed.

Adolescent