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Biomedical subjects

J L Wilson

Publications and source records attributed to J L Wilson.

At least 91 records · Page 5Linked to original sources
PubMed1988

Unusual scalp recorded somatosensory evoked potentials after removal of a large intraventricular meningioma.

Very unusual scalp recorded SEPs were seen in a case after removal of a large intraventricular meningioma. One day before death (ten days after surgery) when the patient was moribund, SEPs from the clinically and radiologically affected hemisphere in which a hematoma and thalamic infarct were found, had a normal latency and were decreased in amplitude. SEPs from the clinically and radiologically nonaffected hemisphere, where only minimal findings were seen, had an abnormally short latency (16.9 msec) and the CCT was only 3.1 msec. We do not offer any logical explanation of these unusual SEP findings from both hemispheres shortly before death.

Cerebral Ventricle Neoplasms↗
PubMed1988

Correlation of broiler breeder male semen production and testes morphology.

Broiler breeder males were fed either a 9, 12, or 15% protein diet (2,819 kcal/kg metabolizable energy) from 6 to 50 wk of age. From 48 through 49 wk of age semen volume (VOL) and concentration (CONC) and number of spermatozoa per ejaculate (NSE) were determined, and at 50 wk of age body weight (BWT) and testes weight (TWT) were measured. Spermatogenic activity was evaluated histologically by a) a computer-aided assessment of seminiferous epithelial area (SEA), tubular diameter (TD), and epithelial height (EH); and b) visual appraisal of seminiferous tubular size and maturity of cell types (testes score-TS). Relationships among NSE, TS, SEA, TD, EH, BWT, and TWT were determined. Dietary protein had no significant effect on VOL, CONC, NSE, BWT, TWT, TS, SEA, EH, or TD. Significant positive correlation coefficients were observed among NSE, TS, SEA, TD, and EH, indicating moderate effectiveness of these methods in evaluating reproductive state. Low correlations between NSE and other variables may have resulted from 25% of the males having high TS but failing to ejaculate semen. Body weight and TWT, as well as BWT and NSE, were positively correlated. The SEA and TD had higher correlations with TWT than with BWT.

Animals↗
PubMed1988

Diverticular disease of the colon.

Diverticular disease of the colon has been called a "deficiency disease of the Western Civilization" and has become increasingly more common in industrialized countries during this century. Diets low in fiber predispose the patient to the development of this condition, and adding fiber to the diet is effective in prevention and treatment. Most patients with the condition are asymptomatic, but many patients experience pain and bowel disturbance along with other symptoms. Complications include infection, bowel obstruction and bleeding, and they may be life threatening. Medical and/or surgical management are indicated.

Diagnosis, Differential↗
PubMed1987

Semen and carcass evaluation of broiler breeder males fed low protein diets.

At 43 days of age, 246 broiler breeder males were randomly assigned to either a 9, 12, or 15% protein diet (isocaloric) fed on a restricted basis until birds were 50 wk of age. Birds fed the 15% protein diet served as the control group for maintaining body weight. All groups received equal quantities of feed. Semen production was monitored weekly from 17 through 49 wk of age. Semen was evaluated for volume, concentration, and number of spermatozoa per ejaculate during four periods: 25 through 30, 36 through 37, 42 through 43, and 48 through 49 wk of age. Carcass composition and testes weight were sampled at 22 and 28 wk; at 50 wk of age all remaining males were analyzed. The dietary protein effect on body weight was linear (P less than .05). Birds fed the 9% protein diet had the lowest weights, while birds fed 12 and 15% protein became similar in body weight with increasing age. Semen volume, concentration, number of spermatozoa per ejaculate, and testes weight were unaffected by dietary protein level. The percentage of males that produced semen when fed the 9% protein diet was greater (P less than or equal to .09) with males fed 12 and 15% dietary protein. Dietary protein had a significant negative linear effect (P less than or equal to .001) on percent carcass fat at 50 wk of age but no effect on percentage carcass protein. Reducing dietary protein to 9% decreased male body weight slightly, increased carcass fat, and had no adverse effects on semen production through 50 wk of age.

Age Factors↗
PubMed1986

Determination of the spatial and intensity properties of atrial repolarization potentials in the dog.

Body surface electrical potentials generated by atrial repolarization (Ta wave) normally extend from the P wave into or through the QRS complex. Thus, the Ta wave is partially obscured by the QRS complex and, conversely, the QRS complex is composed of atrial recovery as well as ventricular depolarization forces. To better study the spatial patterns and magnitudes of the Ta wave, transient atrioventricular (AV) block was induced in 15 dogs by atrial pacing using surgically implanted left or right atrial electrodes. ECG potentials were registered from 84 torso electrodes, and cycles with normal and with blocked AV conduction were segregated. In blocked cycles, the duration of the Ta wave measured 248.0 +/- 25.3 msec with right and 256.0 +/- 38.4 msec with left atrial stimulation. In all cases, the Ta wave extended into the QRS and, in 75% of cases, it extended into the S-T segment. Peak Ta magnitudes, measuring 50.7 +/- 17.9 and 51.8 +/- 21.7 uV RMS with right and left atrial stimulation, respectively, occurred during the P-R segment in all cases. The effect of Ta wave superposition on the QRS complex was assessed by subtraction of patterns in cycles with blocked AV conduction from those with intact AV conduction. Differences between directly recorded QRS waveforms and those computed by subtraction of the Ta wave were small; correlation coefficients exceeded 0.96 and differences in instantaneous RMS potential were less than 6%. Thus, the atrial recovery waveform does extend into the QRS and into the S-T segment in most cases, but the effect of this superposition of Ta on QRS waveforms is quantitatively small.

Animals↗
PubMed1986

R and S wave changes produced by experimental nontransmural and transmural myocardial infarction.

Electrocardiographic R and S wave changes occur after transmural myocardial infarction. It was the purpose of this study to define the spatial characteristics of these changes and their pathologic determinants after nontransmural as well as transmural necrosis. Twenty-six dogs were studied after occlusion of the left circumflex coronary artery for 60 to 240 minutes, followed by reperfusion. Electrocardiographic potentials were recorded before and 1 week after infarction using an 84 electrode array to compute maximal and root-mean-square R and S wave voltages. Infarct size was quantitated by computer-aided evaluation of heart slices stained by triphenyltetrazolium chloride. R and S wave amplitudes after infarction varied widely from one torso site to another in a pattern generally consistent with the inferoposterior location of the infarcted zones. Although changes in peak R and S wave potentials did not significantly correlate with infarct size, differences in pre- and postocclusion root-mean-square R and S wave amplitudes did, with correlation coefficients of -0.79 and -0.63, respectively. Root-mean-square values increased for small lesions and decreased for larger ones. These data indicate that nontransmural as well as transmural infarction can produce R and S wave changes that are dependent on overall lesion size and the specific lead studied. Such changes may represent useful methods to quantitate lesion size.

Animals↗
PubMed1986

Regional blood flow correlates of ST segment depression in tachycardia-induced myocardial ischemia.

Tachycardia produces subendocardial ischemia and ST segment abnormalities after coronary obstruction. To determine whether a quantitative relationship exists between these ST shifts and transmural blood flow, 19 dogs were studied. Coronary obstruction was produced by ameroid constriction of the left circumflex artery, and tachycardia was generated by atrial pacing at 90 to 210 beats/min. ST shifts were studied by body surface isopotential mapping with an 84-electrode torso grid, and blood flow was quantitated by serial radiolabeled microsphere injections. Isopotential maps at each paced rate, 40 msec into the ST segment, were classified as normal or ischemic based on spatial patterns of voltages. Pacing after 3 weeks of ameroid constriction reduced endocardial/epicardial flow ratios in 11 dogs from 1.16 +/- 0.22 at rest to 0.41 +/- 0.18 at 210 beats/min. Abnormal ST depression developed in these dogs at a rate of 184.0 +/- 16.5 beats/min. Endocardial/epicardial ratios with ST depression (0.45 +/- 0.15) were lower than at those without ST depression (1.05 +/- 0.19; p less than .01). Logistic regression analysis demonstrated that ST depression corresponded to an endocardial/epicardial ratio of 0.67 or less (p less than .01). With this model, 95.5% of data sets were correctly classified. Neither heart rate nor perfusion bed size were significant independent predictors of an ischemic electrocardiographic response. The magnitude of abnormal ST segment shift was significantly correlated (r = .87) with the transmural flow ratio. Thus development of electrocardiographic changes indicative of ischemia corresponds to a predictable degree of flow redistribution and the magnitude of the ST shift is correlated with the intensity of the flow abnormality.

Animals↗
PubMed1985

Effects of experimental myocardial infarction on the ST segment response to tachycardia.

Prior studies have shown that tachycardia results in ST segment depression in dogs with chronic, gradual coronary occlusion. This response was compared with that produced by acute, total occlusion of the left anterior descending artery. Ten dogs served as controls; in another 10 dogs, an ameroid constrictor was implanted about the left anterior descending artery. This artery was acutely ligated in a third set of 10 animals, and in a final set of 10, the distal left anterior descending coronary vasculature was embolized by latex injection. Tachycardia was produced by atrial pacing from rates of 90 to 250 beats/min using implanted atrial electrodes. Electrocardiographic signals registered from 84 torso electrodes were used to construct body surface isopotential maps during the ST segment. In normal dogs, pacing increased repolarization potentials without shifts in spatial features. New and abnormal anterior negativity, correlating with significant ST depression, appeared at rates of 170 beats/min or faster in dogs with ameroid constriction. However, in both groups with acute occlusion that produced transmural myocardial infarction, tachycardia resulted in increases in anterior ST elevation and reciprocal ST depression. Specific findings demonstrated the lead dependency of the response to tachycardia and the greater than normal increase in potential magnitudes after infarction than in control cases. The similarity of the response with acute occlusion and with embolization suggested that the response to tachycardia after infarction was not dependent on coronary collateral function but may represent a direct electrophysiologic effect of rate. Thus, these acute occlusion models simulate exercise-induced ST segment elevation as it may be seen clinically.

Animals↗
PubMed1985

Electrocardiographic effects of experimental nontransmural myocardial infarction.

Clinical and experimental data have documented the ability of nontransmural myocardial infarction to produce abnormal Q waves on both the epicardial and body surfaces. We undertook this study to define the anatomic determinants of such Q wave development. Thirty dogs were studied before and after occlusion-reperfusion (26 dogs) or latex embolization (four dogs) of the left circumflex coronary artery. Occlusion was maintained for 60 to 240 min before reperfusion to produce nontransmural lesions of various sizes. Electrocardiographic data were registered from 84 torso electrodes by body surface mapping techniques before and 1 week after infarction. Infarct size was quantitated by computer analysis of heart slices stained with triphenyl tetrazolium chloride. Six dogs did not develop infarction. Of the remaining 24, 10 did and 14 did not develop significant changes in body surface Q wave duration and width. The incidence of Q wave changes was not different in dogs with nontransmural and those with transmural lesions. Infarct size (expressed as a percentage of the left ventricle infarcted), the percentage of endocardium subjacent to infarction, the average depth of necrosis, the percent of the four outer fifths of the ventricular wall infarcted, and the duration of occlusion were significantly (p less than .05) greater in dogs with than in those without Q wave changes. Logistic regression modeling demonstrated that only two anatomic parameters--percentage of left ventricle infarcted and average lesion depth--significantly and independently predicted Q wave development. A model including only these two variables accurately classified all 24 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Effects of light and feeding space on leg abnormalities in broilers.

The influence of two management factors on the incidence and severity of leg abnormalities was studied in three experiments utilizing a total of 7200 male broiler chickens. Birds provided intermittent illumination (IL) had significantly fewer and less severe leg abnormalities than birds under continuous illumination. Broilers given 2.94 cm of feeding space per bird had more but less severe leg defects than birds given 1.47 cm of feeding space. Bird activity was greater under IL and is deemed to be at least partially responsible for the stronger legs recorded among broilers under this management practice.

Animal Husbandry↗
PubMed1982

Myocardial infarction in dogs with acute and gradual occlusion of the circumflex or right coronary arteries.

This study was designed to quantitate and describe the incidence and magnitude of myocardial infarction in the canine heart following acute and gradual occlusion of the circumflex or right coronary arteries. In animals with acute occlusion, the circumflex artery was ligated just distal to the bifurcation of the left coronary artery for 4 hr (seven dogs). Gradual occlusion was produced by placing an Ameroid occluder on the circumflex artery for 1 month (nine dogs), 3 months (nine dogs), and 5 months (eight dogs) and on the right coronary artery for 3 months (nine dogs). Ten dogs served as controls. At the end of the experiments the dogs were sacrificed, and identification of myocardial infarction was made with an enzyme-mapping technique in dogs with acute occlusion and with histological methods in dogs with gradual occlusion. The volume of ventricular infarction was determined with the use of an Apple II Computer and graphics tablet. After 3 months, gradual occlusion of the right coronary artery produced a 22% incidence of infarction which was significantly less (P less than .01, chi 2) than the 67% incidence observed with 3 months of gradual circumflex occlusion. The average infarct volume produced by gradual right coronary occlusion was 0.94 + 0.69%. The average volume of left ventricular infarction in animals with circumflex acute occlusion was 15.6% + 6.6 and the incidence of infarction was 100%. With gradual occlusion of the circumflex artery for 1, 3, and 5 months, average left ventricular infarction was 2.02 +/- 1.01%, 3.13 +/- 1.53%, and 2.96 +/- 1.35%, respectively. There were no significant differences in the amount of damage observed among the three groups with gradual occlusion, and the average incidence of infarction for these three groups was 76%. In the 1-, 3- or 5-month animals with circumflex occlusion, no additional areas of necrosis subsequent to the original damage were found, indicating that infarction is a single event in this model of gradual occlusion. These results suggest that infarct size is determined primarily by factors at the time of total occlusion and that gradual occlusion allows sufficient time for collateral growth, thereby limiting the extent of myocardial injury.

Acute Disease↗
PubMed1982

Cytoreductive surgery and systemic bacillus Calmette-Guerin therapy in metastatic renal cancer: a phase II trial.

A phase II trial has been conducted to determine the effect upon survival of cytoreductive surgery (nephrectomy) and adjuvant active immunotherapy (bacillus Calmette-Guerin) in patients with stage IV renal cancer. A total of 20 patients underwent removal of the primary tumor and received bacillus Calmette-Guerin therapy (adjuvant group). The results were compared to those obtained in 20 historical controls treated with conventional methods (hormones, chemotherapy and radiotherapy with or without nephrectomy) and 16 concurrent controls. All patients in the historical control group were dead within 4 years after the diagnosis of metastases. Seven patients (35 per cent) in the adjuvant group were alive 2 to 5 years after documentation of metastatic disease and onset of therapy. The ratio of observed to expected deaths in the adjuvant group was 0.59 compared to 1.6 in the historical controls. This superior survival was statistically significant (p less than 0.01). A difference in survival between the adjuvant group and concurrent controls also was present but was not statistically significant (0.10 less than p less than 0.20). Other factors suspected to influence survival were investigated. We found that in addition to bacillus Calmette-Guerin therapy a prolonged interval free of disease and better performance status had a better prognosis. Location of metastases, nephrectomy, age and sex are of no significant prognostic value. Definitive answers on the therapeutic value of bacillus Calmette-Guerin and the influence on survival of various biological factors can only be provided by large, controlled, randomized and stratified (phase III) trials.

Adenocarcinoma↗