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Biomedical subjects

J R Wilson

Publications and source records attributed to J R Wilson.

At least 235 records · Page 13Linked to original sources

Neuronal and synaptic structure of the dorsal lateral geniculate nucleus in normal and monocularly deprived Macaca monkeys.

The dorsal lateral geniculate nucleus (dLGN) of Macaca monkeys was studied by Golgi and quantitative electron microscopic (EM) methods to determine if differences in neuronal morphology exist which might correlate with the known physiological separation of X-type cells into the parvocellular and Y-type cells into the magnocellular laminae. Monocularly lid-sutured Macaca monkeys were also studied by quantitative EM methods to compare the synaptic organization within laminae innervated by the deprived and nondeprived retinae. We have divided our sample of Golgi-impregnated neurons into three groups: Types A, B, and C. Type A neurons comprise the majority of the projections cells and are quite heterogeneous in their overall morphology. Type B neurons have long dendrites with multiple appendages; some have a locally ramifying beaded axon Type C neurons are characterized by dendrites which are mainly restricted to the interlaminar zones. We found Type A and B neurons in both the parvocellular and magnocellular laminae. The cell bodies of Type C neurons lay within the interlaminar zones or the parvocellular laminae. All three types contributed dendrites to the interlaminar zones. No significant differences in Golgi morphology other than overall size were found in parvocellular or magnocellular laminae that would explain the previously demonstrated electrophysiological differences. Terminal profiles and synapses in the parvocellular, magnocellular, and interlaminar zones were classified and counted using quantitative EM methods. RSD and F terminals were most numerous in all three zones. RLP terminals were rare in the interlaminar zones. A new type of terminal, RMD was found in the magnocellular interlaminar zones. The laminar and interlaminar zones have the same overall synaptic density, but differed in types of synaptic terminals. The only quantitative difference between any of these regions was in the magnocellular laminae where the counts showed 70% more F terminals per unit area. The same quantitative methods were applied to the laminar and interlaminar zones of dLGNs from monocularly lid-sutured monkeys. We found no qualitative or quantitative difference between the synaptology of zones receiving input from the deprived retina compared to the open eye retina, nor between any regions of the dLGN in deprived monkeys compared to normal monkeys.

Animals↗

Further evidence of an early critical period in the development of the cat's dorsal lateral geniculate nucleus.

The concept of an early postnatal critical period of development for the lateral geniculate nucleus was assessed by determining in adult cats whether previously established properties of geniculate neurons could be altered by varying the cat's visual experience. The analysis was limited to lamina A1 and the binocular segment of lamina A, and the properties studied were the percentage of physiologically recorded Y-cells and cell soma size. Eleven experimental cats in four groups were studied, and three cats reared normally plus three cats reared with continuous monocular lid suture served as controls. Two cats raised first with monocular suture followed by a prolonged period in adulthood with both eyes open had cell size distributions and Y-cell proportions that were indistinguishable from cats raised with continuous monocular suture. Four cats raised first with one eye sutured underwent a reverse suture procedure in adulthood (i.e., the originally sutured eye opened and the other closed) and were maintained in this fashion for a prolonged period. These cats also had geniculate cell size distributions and Y-cell proportions that were indistinguishable from cats raised with continuous monocular suture. Two cats were raised first with binocular suture followed by a prolonged period in adulthood with one eye opened. Their geniculate cell size distributions and Y-cell proportions showed no effect on the adult monocular deprivation and were indistinguishable from previously published data concerning cats raised with continuous binocular suture. Finally, three normally raised cats underwent a prolonged period of monocular suture in adulthood. Their geniculate cell size distributions and Y-cell proportions showed no effects on the adult monocular deprivation. From these data, we conclude that an early critical period of development occurs for geniculate cell sizes and Y-cell proportions. Adult visual environments, whether normal or abnormal, had no detectable effect on geniculate neurons for these previously developed properties, whether normal or abnormal.

Age Factors↗

Evaluation of M-mode echographic estimates of left ventricle function: relationship of selected ultrasonic and hemodynamic parameters.

We examined the relationship between echocardiographic and hemodynamic parameters in 48 patients with left ventricular ejection fractions less than 50% without primary valvular disease. Pulmonary wedge pressure (PWP) correlated with the PR-AC interval (r = -0.62) and with left atrial dimension (r = 0.64) but not with left ventricular diastolic dimension. A PR-AC interval less than or equal to 60 msec was observed in 26 of 29 (90%) patients with a PWP greater than or equal to 14 mm Hg versus 1 of 10 (10%) patients with a PWP less than 14 mm Hg. The correlation between PWP and the PR-AC interval was substantially better in patients with a PR interval less than or equal to 200 msec (r = -0.79) than in patients with a PR interval greater than 200 msec (r = -0.55). The PR-AC interval also correlated with the ejection fraction (r = 0.47). A left atrial dimension greater than or equal to 4.0 cm was observed in 29 of 35 (83%) patients with a PWP greater than or equal to 14 mm Hg versus 0 of 9 (0%) patients with a PWP less than 14 mm Hg. Stroke volume (SV) correlated with aortic root excursion (r = 0.71) and with SV calculated from formulas based on mitral valve motion (r = 0.76) or aortic valve motion (r = 0.62). However, no echo formula provided valid estimates of cardiac output. We conclude that M-mode echocardiography provides a relatively useful noninvasive method of assessing left ventricular filling pressure in patients with reduced ejection fraction and no valvular disease.

Adult↗

Effects of isosorbide dinitrate and hydralazine on regional metabolic responses to arm exercise in patients with heart failure.

The reduced exercise capacity of patients with heart failure is thought to be due in part to impaired skeletal muscle oxygen delivery. To determine if hydralazine and isosorbide dinitrate improve skeletal muscle oxygen delivery in such patients, the effects of these agents on regional metabolic responses to forearm exercise were examined in 16 patients with heart failure. Arm oxygen extraction and branchial venous lactate concentration were measured at rest and during 3 minutes of rhythmic handgrip and then remeasured after administration of oral hydralazine (nine patients) or sublingual isosorbide dinitrate (nine patients). Hydralazine increased mean (+/- standard deviation) cardiac output at rest from 3.5 +/- 0.5 to 4.9 +/- 1.0 liters/min (p less than 0.01) and decreased arm oxygen extraction from 39 +/- 8 to 33 +/- 10 percent (probability [p] less than 0.01), suggesting improved resting limb oxygen delivery. However, hydralazine did not reduce arm oxygen extraction during exercise (control 63 +/- 4, hydralazine 60 +/- 12 percent; p = not significant [NS]) or venous lactate during exercise (control 16.6 +/- 7.8, hydralazine 17.1 +/- 4.8 mg/100 ml; p = NS). Isosorbide dinitrate increased the cardiac output from 3.6 +/- 0.7 to 4.5 +/- 0.7 liters/min (p less than 0.01) but had no effect on arm oxygen extraction at rest (control 40 +/- 11, isosorbide dinitrate 38 +/- 11 percent; p = NS) and during exercise (control 66 +/- 5, isosorbide dinitrate 64 +/- 8 percent; p = NS) or on venous lactate during exercise (control 17.9 +/- 6.4, isosorbide dinitrate 17.1 +/- 3.9 mg/100 ml; p = NS). These data suggest that hydralazine and isosorbide dinitrate do not improve skeletal muscle oxygen delivery during exercise in patients with heart failure.

Adult↗

Circulatory improvement after hydralazine or isosorbide dinitrate administration in patients with heart failure. Effect on metabolic responses to submaximal exercise.

Hydralazine and isosorbide dinitrate can increase the cardiac output during submaximal exercise in patients with heart failure but whether this increase improves oxygen delivery to underperfused exercising muscle is uncertain. To investigate this question, we measured three systemic markers of skeletal muscle oxygen availability--exercise VO2, mixed venous lactate concentration and oxygen debt--during submaximal exercise in 15 patients with heart failure both before after hydralazine (nine patients) or isosorbide dinitrate (eight patients) administration. Hydralazine increased the cardiac output during exercise from 4.9 +/- 1.2 liter/min to 6.5 +/- 1.8 liter/min (p less than 0.01) but had no effect on exercise VO2 (control, 531 +/- 135 ml/min; hydralazine, 489 +/- 102 ml/min), peak lactate concentration (control, 18.3 +/- 4.2 mg/dl; hydralazine, 17.9 +/- 3.6 mg/dl) or oxygen debt (control, 474 +/- 213 ml; hydralazine, 465 +/- 170 ml) (all p greater than 0.10). Isosorbide dinitrate increased the cardiac output during exercise from 4.6 +/- 0.9 liter/min to 5.3 +/- 0.8 liter/min (p less than 0.01) but also did not change exercise VO2 (control, 488 +/- 62 ml/min; isosorbide, 473 +/- 44 ml/min), peak lactate concentration (control, 19.2 +/- 6.0 mg/dl; isosorbide, 21.4 +/- 8.2 mg/dl) or oxygen debt (control, 522 +/- 154 ml; isosorbide, 445 +/- 147 ml) (all p less than 0.10). We conclude that short-term administration of hydralazine or nitrates to patients with heart failure can substantially improve circulatory function during exercise but that this improvement probably does not enhance skeletal muscle nutritional flow.

Adult↗

Effect of diuresis on the performance of the failing left ventricle in man.

To determine the effect of diuresis on the performance of the failing left ventricle, we measured cardiac output, pulmonary wedge pressure and M-mode echo left ventricular diastolic dimension before and after diuresis in 13 patients with heart failure. Diuresis increased stroke volume (43 +/- 23 ml to 50 +/- 18 ml (p less than 0.05)) and decreased pulmonary wedge pressure (28 +/- 3 mm Hg to 19 +/- 5 mm Hg (p less than 0.01)), mean blood pressure (100 +/- 14 mm Hg to 88 +/- 10 mm Hg (p less than 0.01)) and systemic vascular resistance (2,059 +/- 622 dynes-sec-cm-5 to 1,783 +/- 556 dynes-sec-cm-5 (p less than 0.05)). Echo left ventricular diastolic dimension was not changed by diuresis (6.0 +/- 0.8 cm to 6.0 +/- 0.8 cm). Percent change in stroke volume correlated with systemic vascular resistance (r = 0.60, p less than 0.05) and with left ventricular diastolic dimension (r = 0.62, p less than 0.05) but not with pulmonary wedge pressure (r = 0.12) or right atrial pressure (r = 0.04). Thus, diuresis improved the performance of the failing ventricle and reduced afterload, but it did not alter left ventricular diastolic dimension, an index of preload. These data suggest that diuresis improves ventricular function by decreasing afterload.

Aged↗

Viability and sensorimotor development of mice exposed to prenatal short-term ethanol.

The identification of the fetal alcohol syndrome in man has led to an abundant, but sometimes contradictory body of research examining the effects of prenatal ethanol exposure in animals. The present study examines the early sensorimotor development of heterogenous stock mice after ethanol exposure during one of two time periods in gestation, days 8--12, or days 14--18. Animals received either a liquid diet containing 20% ethanol derived calories, an isocalorically balanced yoked control diet or a lab chow control diet. Results indicated no apparent effects due to administration of alcohol during the middle of gestation, but a marked decrease in offspring viability, birthweight, and growth due to administration during the last part of gestation. The late gestation treatment group also showed a slight delay in the rate of development of the grasping and horizontal screen tasks. Overall, animals that survived showed relatively normal sensorimotor development.

Aging↗

Behavioral and physiological measures for studying ethanol dependence in mice.

In the initial experiment, 20 male and 20 female heterogeneous stock (HS) mice were divided randomly into experimental and control groups. Ethanol was administered in liquid diet form to the experimental group in increasing dosages for a 9-day period followed by behavioral and physiological tests to determine differences between groups and genders 6 to 7 hr post-withdrawal. Analysis of data showed significant differences between the ethanol-treated and control groups for at least six of the measures. In addition, significant gender differences and significant interactions between gender ant treatment group were found for four of the measures; in all of these cases, females appeared to exhibit a less severe withdrawal syndrome than males. In a second experiment, no gender difference in rate of ethanol disappearance from the blood could be found in 36 HS mice tested at 1 to 3 hr post-withdrawal.

Alcoholism↗

Effects of respiratory alkalosis on coronary vascular dynamics and myocardial energetics in patients with coronary artery disease.

To determine if respiratory alkalosis produces hemodynamically significant coronary vasoconstriction in coronary artery disease (CAD), we studied the effects of hyperventilation on coronary sinus blood flow (CSBF), myocardial O2 uptake, and lactate extraction in 13 CAD patients. No patient developed chest pain or ischemic ECG changes during hyperventilation. Hyperventilation increased pressure-rate product (myocardial O2 consumption index, MVO2) minimally did not change global CSBF, coronary vascular resistance or lactate extraction. However, hyperventilation increased global myocardial O2 uptake from 14.5 plus or minus 3.2 to 18.7 plus or minus 17.2 ml/min (p less than 0.01) principally due to increased myocardial O2 extraction (65.0 plus or minus 7.4 to 71.6 plus or minus 6.2%, p less than 0.01). The increased pressure-rate product was not sufficient to account for increased myocardial O2 uptake. We conclude that respiratory alkalosis increases myocardial O2 extraction but does not produce hemodynamically significant coronary vasoconstriction in CAD patients.

Adult↗

Partition coefficients of some aromatic alcohols in an n-heptane/water system and their relationship to minimum inhibitory concentration against Pseudomonas aeruginosa and Staphylococcus aureus.

The partition coefficients of the homologous series of aromatic alcohols were determined in an n-heptane/water system. The minimum inhibitory concentrations of benzyl alcohol, 2-phenylethanol, 3-phenylpropanol, 4-phenylbutanol and 5-phenylpentanol were elucidated against Pseudomonas aeruginosa and Staphylococcus aureus. The linear relationship log1/C = a log P + b postulated by Hansch was found to apply.

Alcohols↗

Serum levels of glycosyltransferases and related glycoproteins as indicators of cancer: biological and clinical implications.

Many studies have suggested that malignant transformation is associated with fundamental changes in the cell surface; similar changes have been described for normal stem cells and cells of embryonic or fetal origin. There is now evidence that the tumor cell secretes or sheds glycoproteins and glycosyltransferases into the surrounding medium and into serum. There are claims that some of these serum glycoproteins and glycosyltransferases are associated with, or specifically related to, the extent of tumor growth and may serve as a cancer marker. A cancer-associated galactosyltransferase isoenzyme (GT-II) has been described and purified. Different isoelectric forms of fucosyltransferase have also been described as indicative of malignancy. The articles to be published in CRC Critical Reviews in Clinical Laboratory Sciences will analyze the evidence for the association of these membrane factors with tumor growth. In order to better understand the possible significance of altered glycoproteins and of increased or different forms of glycosyltransferases during tumor growth, recent data on glycoprotein synthesis will be discussed including the new concepts on the control of glycoprotein synthesis through lipid intermediates. The possible mechanisms whereby malignant transformation could alter glycoprotein synthesis will be discussed with particular emphasis on the significance of these alterations to the biology of the malignant cell. Changes in surface membrane glycoproteins have long been implicated in the ability of a cell to metastasize. Secretion and/or shedding of the cell surface may also be important in the process of metastasis and in altering the host immune response. Detection and the study of these "shed" materials in patients appear to be indicating a new approach to cancer biology detection and therapy.

Animals↗

Fertility, maternal care, and offspring behavior in mice prenatally treated with tobacco smoke.

Female mice from lines selectively bred for differences in open-field activity were exposed to tobacco smoke during gestation. Smoke-treated females were less likely than controls to have produced litters by 23 days after observation of a vaginal plug. Within the high-active line, fewer pups of smoke-treated dams survived to weaning. Regardless of treatment, fewer high-active than low-active offspring survived to weaning. Results of a 4-day series of open-field activity tests administered to offspring beginning at 28 days of age indicated that tobacco smoke administered prenatally and/or during testing depresses open-field activity in both lines. Other activity tests administered at 50 days of age gave similar results. Tissue nicotine levels after nicotine injection tended to be higher in high-active and control groups than in low-active and smoke-treated groups, respectively. Liver weight expressed as percentage of body weight was 11.9% greater in smoke-treated animals than in controls.

Animals↗

Noninvasive assessment of load reduction in patients with asymptomatic aortic regurgitation.

Afterload reduction in chronic asymptomatic aortic regurgitation might retard left ventricular enlargement and hypertrophy and, consequently, delay the onset of myocardial dysfunction and the need for surgical intervention. Since afterload is best expressed as wall stress, the effect of nitroglycerin on wall stress was determined in 10 normal subjects and in eight asymptomatic subjects with aortic regurgitation and normal left ventricular and circulatory function. Peak and end-systolic wall stress were estimated using a noninvasive echocardiographic technique. At rest, despite significantly larger left ventricular dimensions in the subjects with aortic regurgitation, peak systolic wall stress in this group (134 +/- 29 X 10(3) dynes/cm2) was similar to that in normal subjects (134 +/- 26 X 10(3) dynes/cm2). In contrast, end-systolic wall stress was higher in aortic regurgitation (84 +/- 12 versus 59 +/- 15 X 10(3) dynes/cm2) (P less than 0.01). Following the administration of nitroglycerin, the subjects with aortic regurgitation had larger reductions in left ventricular end-diastolic (3.5 mm) and end-systolic (3.1 mm) dimensions than did the normal subjects (0.6 and 1.1 mm, respectively), despite similar changes in blood pressure. This resulted in normalization of end-systolic wall stress and in reduction of peak systolic wall stress below normal in aortic regurgitation. We conclude that (1) nitroglycerin offers a simple and effective means of acutely reducing afterload in asymptomatic aortic regurgitation; (2) left ventricular dimensional changes after the administration of nitroglycerin are larger in subjects with aortic regurgitation than in normal subjects. Consequently, unloading therapy may be effective in protecting the left ventricle in this disorder.

Adolescent↗

Ergonomics and product liability.

This article discusses the implications for ergonomists of proposed changes in the civil law on product liability. It also considers the ergonomic approach to the prevention of product liability actions. This is the promotion of consumer safety through safe product design. Safety performance testing and standards are examined in the light of the future requirements of manufacturers. The article is based largely upon a paper entitled "The prevention of product liability actions" read at the CBI Conference, Product Safety and Liability for Defects, held at the Inn on the Park, London, September, 1977.

Journal Article↗