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D Davis

Publications and source records attributed to D Davis.

At least 271 records · Page 15Linked to original sources
PubMed1982

Morphometric evaluation of the hypothalamic-ovarian axis of the ketonuric, diabetic Chinese hamster: relationship to the reproductive cycle.

The relationship between diabetes and the morphological alterations which occur in hypothalamic and ovarian tissue was examined in the long-term, ketonuric-diabetic Chinese hamster. Matched diabetic and non-diabetic control hamsters were inspected daily for changes in the reproductive cycle by vaginal lavage. On dioestrus, animals were perfused, the hypothalamus and ovaries collected, prepared for microscopy and morphometrically analyzed. The nuclei in the medial basal hypothalamus of diabetic hamsters exhibited a decreased area (p less than 0.01) and neuronal population (p less than 0.05-0.01) compared with controls. The ovaries of the diabetic animals had a reduced follicular population (p less than or equal to 0.05) and an increased atresia rate (p less than or equal to 0.05) compared with controls. In addition, all diabetic hamsters were acyclic. In diabetic animals, the corpora luteal cells contained a reduced lipid content (p less than or equal to 0.001) which was possibly functionally related to a significant decline in serum progesterone levels (p less than or equal to 0.01). Based on these results it is suggested that the hypothalamic-ovarian axis is both morphologically and functionally impaired in the diabetic hamster.

Animals↗
PubMed1982

A comparison of the effects of lactose and of two chemically modified waxy maize starches on mineral metabolism in the rat.

Diets containing 30% by weight of waxy maize starch, lactose monohydrate, acetylated distarch phosphate (EEC No. 1414) or acetylated distarch adipate (EEC No. 1422) were fed to weanling female Specified Pathogen-Free Sprague-Dawley rats for 1 yr and to similar 9-month-old rats for 34 wk. Behaviour and general health were unaffected by the different diets and there were no diet-related differences in food consumption. AT the end of the experiment with 9-month-old rats the mean body weight of the animals receiving lactose was significantly lower than that of the controls receiving starch. The animals receiving the modified starches were slightly but not significantly heavier than the controls at the end of both experiments. The main treatment-related changes in rats on the three test diets were (1) caecal enlargement, (2) increased urinary excretion of calcium, (3) increased renal calcification as measured by chemical analysis of renal tissue obtained at autopsy and (4) increased medullary and pelvic nephrocalcinosis as assessed histopathologically. Acetylated distarch adipate had a slightly greater effect on the above parameters than acetylated distarch phosphate but both modified starches had less effect than lactose. The calcium content of the kidneys, as measured by chemical analysis or histopathology, increased with age, even in the animals receiving the control diet. This change may be due to excessively high concentrations of calcium and phosphorus in all the diets, including the control diet. Cortico-medullary mineral deposits were not a feature in these studies possibly because the diets were not deficient in magnesium. The importance of correct dietary formulation in long-term toxicity studies is emphasized.

Animals↗
PubMed1982

Diazepam and lidocaine plasma protein binding in renal disease.

The plasma protein binding of diazepam and lidocaine was measured in patients with renal disease (those with uremia, nephrotic syndrome, or who had received a transplant) and in age- and sex- matched control subjects. Percentage unbound diazepam in plasma was increased over control in all three groups of patients as follows: uremic patients 3.23%, control, 1.64% (P less than 0.001), nephrotic patients, 3.55%, control, 1.63% (P less than 0.001); and transplant recipients, 2.11%, control 1.50% (P less than 0.001). The binding ratio (molar concentration of bound to unbound drug) in patients was related to albumin concentration (r = 0.609, P less than 0.001). Percentage of unbound lidocaine did not differ substantially from control in nephrotic patients (34.2%, control 30.8%), but was reduced in the uremic patients (20.8%, control 30.7%, P less than 0.001) and transplant recipients (24.6%, control 33.7%, P less than 0.005). These increases were associated with increases in alpha 1-acid glycoprotein (AAG) concentration (uremic patients 134.9 mg/dl, control 66.3, P less than 0.001; transplant recipients 106.5, control 65.6, P less than 0.001). The binding ratio of lidocaine was closely related to the AAG concentration in patients (r = 0.933, P less than 0.001) and controls (r = 0.719, P less than 0.001). Thus, the binding of basic drugs may be increased or decreased in patients with renal disease, depending on the relative contribution of the individual plasma to the total binding and the type of disease.

Adult↗
PubMed1982

The McMaster CME Society.

Registration for continuing medical education (CME) at McMaster University Faculty of Health Sciences may be achieved in two ways: by separate registration for each course or by prepaying an annual fee that enables the physician to attend all or parts of any CME activities in a 12-month period. The latter method also provides membership in the McMaster Continuing Medical Education Society. This society, in operation at McMaster for the past three years, was conceived with the following objectives: to decrease the cost per course to the physician; to allow for selectivity in course material; and, perhaps most importantly, to increase the motivation of physicians to attend CME activities. Achievement of the objectives has provided a funding base on which to build CME events and has permitted the use of input of members of the society as a planning guide.

Canada↗
PubMed1982

Volume averaging limitations of computed tomography.

A simple volume averaging model was shown to be inadequate for predicting effective computed tomographic attenuation values of mixtures of bone or air with soft tissue. Computed tomographic values derived from scanning stratified sub-slice thickness objects were shown theoretically and experimentally to have a non-linear dependency on relative fractional content and a surprisingly large dependency on spatial extent of the stratified substances. The mode was applied to the problem of computed tomographic values in thin, flat structures such as pools of blood in the subarachnoid space. The results show only small deviations from simple volume averaging theory for layers of low contrast substances such as blood and soft tissue, but potentially large deviations for layers of substances with high contrast differences such as bone, air, and tissue. This phenomenon explains certain artifacts and demonstrates rather fundamental problems in the accuracy of analytic reconstruction techniques. It may justify postprocessing correction or iterative approaches.

Mathematics↗
PubMed1982

Depression.

Explore the source record for details and available documents.

Adult↗
PubMed1981

Effect of antimicrobial agents on human polymorphonuclear leukocyte microbicidal function.

The effect of 19 antimicrobial agents on human polymorphonuclear leukocyte function was evaluated by chemiluminescence assays, yeast phagocytosis and killing, and lactate dehydrogenase release. Tetracycline and trimethoprim inhibited chemiluminescence and reduced killing at therapeutic concentrations of 2 microgram/ml. Cephalothin inhibited yeast killing at a concentration of 20 microgram/ml, but a significant depression of polymorphonuclear leukocyte chemiluminescence was encountered only at higher levels of 200 microgram/ml. The inhibition shown by these drugs was reversible. None of the other antimicrobial agents tested demonstrated inhibition of chemiluminescence, phagocytosis, or killing at usual clinical serum levels. No antimicrobial agent tested caused release of lactate dehydrogenase from polymorphonuclear leukocytes. The results suggest that therapeutic concentrations of tetracycline, trimethoprim, and cephalothin may inhibit optimal polymorphonuclear leukocyte microbicidal function.

Anti-Infective Agents↗
PubMed1980

Effect of hemodialysis on hallucinations.

A patient with chronic schizophrenia had two hemodialyses and two sham dialyses in a single-blind design. There was no change in the patient's affect after either procedure, but her auditory hallucinations disappeared after both hemodialysis and sham dialysis, with hemodialysis inducing a much longer partial remission.

Adult↗
PubMed1980

Hemodialysis and schizophrenia: a double-blind study.

Partial or total remission of schizophrenic symptoms after exchange transfusion or hemodialysis have been reported in the literature. Although the results of these reports are encouraging, they have not been confirmed by controlled studies. We have conducted a double-blind placebo-controlled study to evaluate the effect of hemodialysis on chronic schizophrenia. Our data seem to indicate that some schizophrenic symptoms improve after hemodialyses.

Adult↗
PubMed1980

Cryosurgical ablation of the atrioventricular node-His bundle: long-term follow-up and properties of the junctional pacemaker.

We used a cryosurgical technique to ablate the atrioventricular (AV) node-His bundle in twenty-two selected patients with disabling supraventricular tachyarrhythmias unresponsive to medical management. Successful AV block was achieved in seventeen. There was no intraoperative mortality and significant surgical complications were not encountered. Electrophysiologic studies performed 7-10 days after surgery revealed that the subsidiary pacemaker had a narrow QRS complex morphology and a mean cycle length of 1244 msec. Isoproterenol (1-4 microgram/min i.v.) significantly increased (p less than 0.01) the rate of the subsidiary pacemaker (mean maximum response 1008.3 msec); atropine (2 mg i.v.) had no effect on its rate. The cycle length of the subsidiary pacemaker during long-term follow-up (mean 14.8 months) showed a small but significant (p = 0.024) increase (mean cycle length 1430 msec). Treadmill exercise in seven patients did not result in the subsidiary pacemaker exceeding the rate of the implanted demand pacemaker set at 70 beats/min. The properties of the subsidiary pacemaker suggest an intra-Hisian site of impulse formation.

Adult↗