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Biomedical subjects

D Knox

Publications and source records attributed to D Knox.

31 records · Page 2Linked to original sources

Bilateral gaze paralysis with positive computerized tomography findings. A clinicoanatomic correlation.

The subacute development of an almost isolated bilateral gaze paralysis in a patient with mycosis fungoides allowed a unique opportunity for in vivo clinicoanatomical correlation when enhanced computerized tomography (CT) scan revealed two extremely small lesions of the pontine tegmentum. The larger lesion involved the region occupied by the medial longitudinal fasciculus and the paramedian pontine reticular formation (PPRF) bilaterally, and was alone sufficient to account for the eye movement disorder.

Brain Neoplasms↗

Studies on the nutrition of marine flatfish. The pyridoxine requirement of turbot (Scophthalmus maximus).

1. Diets containing graded levels of pyridoxine hydrochloride (to supply 0.26--30 mg pyridoxine/kg) were given to seven duplicate groups of turbot (Scophthalmus maximus) for 12 weeks and their growth rate was measured during this period. 2. Good growth was obtained on all treatments except those groups given less than 1.0 mg pyridoxine/kg diet. These fish grew normally until weeks 8--10 but thereafter their weight gain was significantly less than that for other treatments. 3. Measurements of aspartate aminotransferase (EC 2.6.1.1) in muscle and liver and of alanine amino-transferase (EC 2.6.1.2) in liver of the turbot showed that the activities of these enzymes increased with increasing dietary pyridoxine intake up to a level of 2.5 mg pyridoxine/kg. The activities of these enzymes were not further enhanced by additional dietary pyridoxine. 4. Percentage stimulation of these enzymes by pre-incubation of extracts with pyridoxal phosphate was minimal with those groups of turbot given 2.5 mg pyridoxine/kg diet or more. 5. It is concluded that the dietary requirement of turbot for vitamin B6 can be safely met with a diet containing between 1.0 and 2.5 mg pyridoxine/kg. 6. An eighth group of turbot given the pyridoxine antagonist 4-deoxypyridoxine hydrochloride (20 mg/kg) showed retarded growth after 2 weeks, together with a high mortality rate.

Alanine Transaminase↗

Alloxan diabetic neuropathy: electron microscopic studies.

Peripheral nerves of diabetic rats were studied 2 years after alloxan injection. We observed demyelination and remyelination, axonal degeneration and regeneration, reduplication of basal laminae around vessels and Schwann's cells, as well as onion bulb formation by proliferated Schwann's cells. Crystalline deposits composed of aggregates of fibrillary electron dense material often occurred in vessel walls and endoneurium of diabetic animals but rarely were seen in nerves from age-matched control animals. Glycogen accumulated in myelinated and unmyelinated axons within mitochondria. Axoplasmic inclusions resembling Lafora's bodies and the inclusions of glycogenosis type IV were frequent and often were accompanied by deposits of particulate glycogen. The findings suggest that the neuropathy in alloxan diabetes is caused by metabolic impairment of anxons, Schwann's cells, and vessels, leading to segmental demyelination and axonal degeneration.

Animals↗

Coping with fatherhood: the first year.

Fantasy (thinking back to prebaby times) and holidays (going out alone with the wife) are examined here as methods of coping with parenthood for 93 white, first-time fathers. Results suggest that only the holiday coping mechanism is associated with maintaining or improving marital satisfaction. The use of fantasy actually decreases marital satisfaction. These data suggest that the discrepancies in the conclusions of previous "parenthood as crisis" studies may be accounted for through the analysis of coping mechanisms that various fathers utilize.

Adaptation, Psychological↗

Studies on the nutrition of marine flatfish. The thiamin requirement of turbot (Scophthalmus maximus).

1. Seven groups of young turbot (Scophthalmus maximus) were given diets containing graded levels of thiamin (0-19--50 mg/kg) for 16 weeks and their growth rate was measured during this period. 2. Good growth was obtained on all these treatments except in the group given the lowest dietary thiamin level (0-19 mg/kg). These fish grew normally until the 12th week but thereafter their weight did not increase. 3. Measurements of erythrocyte transketolase (sedoheptulose-7-phosphate: D-glyceraldehyde-3-phosphate glycolaldehydetransferase; EC 2.2.1.1) activity at the end of the experiment and of percentage stimulation of erythrocyte transketolase by thiamin pyrophosphate indicated that the apoenzyme was saturated with coenzyme at a dietary thiamin level of 2-6 mg/kg, but not at 1-1 mg/kg. 4. An 8th group of turbot given the thiamin antagonist pyrithiamin (40 mg/kg diet) grew normally for 6 weeks. Thereafter mortalities began to occur and all fish died by the 10th week. No clear-cut signs of thiamin deficiency were observed. 5. The dietary thiamin requirement of turbot is much lower than published requirements of freshwater fish other than carp (Cyprinus carpio) and appears to be between 0-6 and 2-6 mg/kg diet.

Animal Nutritional Physiological Phenomena↗

Long term studies of pancreas transplantation in experimental diabetes mellitus.

Alloxan diabetes was induced in inbred rats that then were divided into four groups consisting of unoperated diabetic controls, sham-operated diabetic controls, rats given pancreaticoduodenal isografts, and rats given duct-ligated pancreas isografts. The animals were studied for from 18 months (controls) to two years (transplants) and the following important results were obtained: 1) In striking contrast to the diabetic controls, pancreas transplants of both types produced immediate and permanent relief of hyperglycemia, immediate and lasting elevation of serum insulin levels, a normal weight and growth curve, and good health for two years. Removal of the graft was followed by recurrence of severe diabetes. 2) Pancreas transplants of both types prevented the widespread and severe renal, ophthalmic and neural lesions of diabetes that were found in the diabetic controls. 3) The duct-ligated pancreas graft and pancreaticoduodenal transplant were equally effective in controlling diabetes. Ligation of the pancreatic duct was not followed by significant morphologic or clinical evidence of pancreatitis or by loss of endocrine function. 4) Portal venous drainage of the pancreas transplant was unnecessary for good endocrine function.

Animals↗