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Biomedical subjects

J F Taylor

Publications and source records attributed to J F Taylor.

At least 145 records · Page 8Linked to original sources
PubMed1985

Systematic environmental, direct, and service sire effects on conception rate in artificially inseminated Holstein cows.

Result of insemination was verified for 329,314 artificial inseminations by 882 service sires to 97,245 Holstein cows in 1,075 herds between May 1970 and December 1983. Estimates of systematic environmental and genetic components of cow and service sire components of conception rate were obtained preliminary to development of a fertility monitoring system. Conception rate was 2.9% higher in stanchion than loose housed herds and 2.3% higher in grade than registered cows. Fall months were superior to winter months, the greatest difference being 6.1% between October and January. Conception rate increased with herd milk production, decreased with both increased cow age, and increased herd size in mature and old cows. Regions and inseminators within regions were highly variable. Conception may be influenced by semen price; however, week day of insemination and duration of semen storage had no effect. Conception rate decreased for semen by bulls 8 yr and older, was lowest for semen harvested in June, but no season of collection effect was detected. No genetic trends for cow and service sire conception rate were found; heritability and repeatability were .08 and .06, respectively. Genetic correlations between cow and service sire conception rate and these components with first lactation production and semen output measures were all near zero. Therefore, the relationship between sire fertility and daughter fertility is near zero.

Animals↗
PubMed1985

Decision making in the definitive repair of the heart with a small right ventricle.

Data from 51 patients with small right ventricle who underwent a definitive repair were analyzed retrospectively. The repair was considered complete (29 patients) when it resulted in relief of the right ventricular outflow tract obstruction by closure of intracardiac (atrial septal defect) and extracardiac (when present) shunts. The repair was considered a definitive palliation when the intracardiac and the extracardiac shunts were left open (11 patients). A complete separation of the systemic and pulmonary circulations was established with the use of the Fontan procedure in another 11 patients. The outcome in these patients correlated with the preoperative size of the right ventricular cavity as assessed by measurement of the tricuspid valve diameter and by consideration of the right ventricular morphology (based on the tripartite right ventricular concept). If the tricuspid valve of a tripartite right ventricle has a diameter above the lower 99% confidence limit of the normal mean it can be safely incorporated in a complete repair (p less than .01). This also applies for a right ventricle without a trabecular portion, provided the criteria of the Fontan operation are fulfilled. Right ventricles with tricuspid valve diameters smaller than the lower 99% confidence limit of the normal mean cannot sustain total pulmonary blood flow. Definitive palliation should be reserved for use in patients whose right ventricles are too small for complete repair and who are not suitable candidates for Fontan's procedure.

Adolescent↗
PubMed1984

The radiological evaluation of multiple pin fixation of the femoral head.

Following pin fixation of the femoral neck, extrusion of a pin tip into the joint space cannot be excluded with conventional bi-plane radiography. A per-cervical pin was allowed to extrude from the head of a dried femur. Anteroposterior and lateral photographs and roentgenograms of this preparation, simulating corresponding intra-operative radiology, demonstrated misleadingly that the pin tip was wholly within the head. Careful intra-operative and post-operative screening is considered important to detect unwanted joint penetration and so avoid avascular necrosis and late degenerative change.

Adolescent↗
PubMed1984

Management of critical aortic stenosis in infancy.

Critical aortic valvular stenosis presents in infancy with severe congestive heart failure. Clinical assessment and electrocardiography are of value, but cardiac catheterization with angiography has been considered mandatory prior to surgical treatment. With cross-section echocardiography an accurate diagnosis of aortic stenosis and associated lesions is possible. Over the past 2 years, we have established a protocol according to which, if a clinical diagnosis of critical aortic stenosis is confirmed by cross-sectional echocardiography in the absence of major associated cardiac anomalies, infants are submitted for aortic valvotomy under inflow occlusion without invasive studies. This protocol was used in an effort to decrease the mortality rate by avoiding the preoperative stress of cardiac catheterization and angiography, as well as the hazards of cardiopulmonary bypass in the severely ill infant. Eight infants with critical aortic stenosis have been operated upon, five without prior cardiac catheterization. Ages at operation ranged from 2 days to 7 months, with six children less than 2 weeks of age. The noninvasive diagnosis was confirmed at operation in each case. There was one early postoperative death and one late death. No death has been related to the technique of inflow occlusion. A decision tree for the noninvasive assessment of suspected critical aortic stenosis based on the clinical features and echocardiographic findings is presented.

Aortic Valve↗
PubMed1983

Perthes' disease of the hip in Liverpool.

A survey of Perthes' disease of the hip in three regions of England showed a higher incidence in the Mersey region compared with Trent or Wessex. To explore this further a case register was set up in Liverpool. Analysis of all new cases that occurred in Liverpool and adjacent parts of Knowsley and Sefton during 1976-81 showed a steep gradient with social class, ranging from 7.7/100 000 children in the higher classes to 26.3/100 000 in social class V. The inner city of Liverpool, which has been shown to be underprivileged, had the highest yearly incidence of the disease ever reported--21.1 cases/100 000 children aged 14 years and under. The associations with poverty support the hypothesis that undernutrition is a causative factor in the disease.

Child↗
PubMed1983

Activity-induced morphologic changes in rat soleus nerve.

The effects of 8 to 12 weeks of intense running or swimming on the morphology of the soleus nerve of the adult male albino rat were investigated. Nerve fiber diameter and number, axon diameter, and myelin area were determined. Mean fiber diameter (5.50 +/- 0.47) of the trained rats was smaller (P less than 0.05) than for sedentary control rats (6.19 +/- 0.27). The decrease in fiber size in the trained rats appeared to be reflected by a combination of smaller (P greater than 0.05) mean axon diameter and myelin area. Total fiber number was not different in the control (means = 113 +/- 6) and trained (means = 108 +/- 4) rats. These results provide further evidence that a chronic, intense but physiologic exercise can impose a functional demand on peripheral nerves that can alter morphologic features that are closely related to conduction velocity and commonly are associated with neuronal cell size.

Animals↗
PubMed1983

Congenital heart disease in the neonate: results of surgical treatment.

All 212 neonates undergoing cardiac surgery at this hospital during the 5-year period from 1976 to 1980 inclusive were reviewed. Forty required open heart surgery with 23 (57%) deaths. One hundred and seventy-four neonates underwent non-bypass procedures and could be divided into three groups: group 1 (82 patients) had inadequate pulmonary blood flow, group 2 (33 patients) had increased pulmonary blood flow or inadequate mixing, and group 3 (59 patients) had coarctation of the aorta, alone or with associated lesions. Forty-four (25%) of the neonates undergoing non-bypass procedures died. Two required bypass surgery later in the first month of life. Metabolic acidosis and the need for preoperative respiratory support were appreciably greater in non-surviving patients. The spectrum of diagnoses encountered and types of operative procedures performed are analysed.

Cardiac Surgical Procedures↗
PubMed1983

Costodesis and contralateral rib release in the management of progressive scoliosis.

This paper reports on 41 immature patients whose scoliosis was treated by fixation of ribs on the convexity. All had progressive scoliosis, the curve deteriorating at more than 10 degrees p.a., or the rib-vertebra angle difference being greater than 20 degrees. Of the 24 with infantile idiopathic scoliosis examined 5 years after operation, 10 maintained the improvement obtained at operation and in a further 19 the rate of deterioration had been slowed. Factors leading to a favourable outcome included: 1) An initial rib-vertebra angle difference of less than 30 degrees. 2) Success in achieving convex rib fusion. 3) The use of the operation in patients with infantile idiopathic scoliosis. There was a less favourable outcome in congenital and adolescent scoliosis. Spirometric volumes were diminished immediately after operation. Costodesis is therefore contraindicated in patients with precarious respiratory function.

Child↗
PubMed1983

Differential effects of running and weight-lifting on the rat coronary arterial tree.

Twenty-four postpubertal male albino rats were assigned randomly to sedentary-control (C), endurance-running (ER), and weight-lifting (WL) groups to study the effects of different chronic-exercise regimens on precapillary vascularity in the heart. The exercise routines were administered 5 d/wk. At the end of either 8 or 16 wk of treatments, half of the animals in each group were anesthetized. A 12% vinyl acetate solution was injected into the coronary arteries of each anesthetized animal at a pressure of 300-350 mmHg, through the ascending aorta. The injected hearts were removed and weighed. A 10% potassium hydroxide solution was used to digest tissues from the vinyl cast of each coronary arterial tree. No differences in absolute or relative heart weights were observed between the control and trained groups. When compared to the control group, the ER animals had heavier left and total coronary cast weights and higher total cast weight-to-heart weight ratios (P less than 0.05). Although an overall increase in precapillary vascularity of the heart was evident in the endurance-trained ER animals, none was found in the strength-trained WL group. However, the WL animals had significantly increased right coronary cast weights, and their ratios of right coronary cast weight to total cast weight also were higher than those of the control animals (P less than 0.05).

Animals↗
PubMed1983

Use of a subpulmonary ventricular chamber in the Fontan circulation.

In order to study the usefulness of incorporating a subpulmonary ventricular chamber (SPVC) in the Fontan circulation, we compared the hemodynamics of 18 patients who underwent an atriopulmonary connection with those of 17 patients with an atrioventricular connection. Early postoperatively, regardless of whether an SPVC was incorporated or not, the mean pulmonary artery pressure was not higher than the mean right atrial pressure in any of our patients. The stroke work of the right heart was at best zero, and pressure tracings showed an a wave in the pulmonary artery (right atrium-dependent circulation). If an additional gradient was interposed between the right atrium and pulmonary artery, the effective stroke work of the right heart might be negative and the work curve have a negative slope. This can occur irrespective of the use of an SPVC. In the long term, if it grows sufficiently, an SPVC can sometimes provide a right ventricle-dependent pulmonary circulation with a more normal hemodynamic pattern (mean right atrial pressure less than mean pulmonary artery pressure). We concluded that an SPVC should be used in Fontan's circulation, provided that an obstruction-free atrioventricular connection can be established.

Adolescent↗
PubMed1983

Surgery for congenital heart defects diagnosed with cross-sectional echocardiography.

Between August 1980 and July 1982, 70 children were operated on for congenital heart defects without the use of cardiac catheterization and/or angiocardiography (7.5% of the total of 929 operations). The diagnosis was established by clinical examination, chest x-ray, electrocardiography, and comprehensive cross-sectional echocardiography. The following lesions were repaired: coarctation of the aorta in infancy (n = 28), total anomalous pulmonary venous drainage (n = 6), aortic valvular/subvalvular lesions (n = 11), mitral and tricuspid valve lesions (n = 4), simple transposition of the great arteries (n = 3), vegetations (n = 3), persistent truncus arteriosus (n = 2), and others (n = 13). Three diagnostic errors occurred, and in four children the initial diagnosis was not complete. No child died as a consequence of an error or incomplete diagnosis, and in only one instance was an inappropriate operation carried out (abdominal coarctation of the aorta). We conclude that operation on selected patients can be safely performed on the basis of noninvasive investigation.

Aortic Coarctation↗
PubMed1982

Isolated anterior mitral cleft. Two dimensional echocardiographic assessment and differentiation from "clefts" associated with atrioventricular septal defect.

Five patients with isolated clefts in the anterior leaflet of the mitral valve, unassociated with atrioventricular septal defects, are described. All had significant mitral regurgitation, with the cleft being the only abnormality in three. Two patients had an associated ventricular septal defect, one with a straddling right atrioventricular valve. Angiocardiography in four showed moderate regurgitation, but was not able to delineate the aetiology. Two dimensional echocardiography showed a constant defect in the anterior leaflet, pointing towards the left ventricular outflow tract. This differed from 30 cases with atrioventricular septal defects where the "cleft" pointed towards the interventricular septum and was situated between the anterior and posterior bridging leaflets. All cases with isolated clefts had surgical correction, with minimal residual regurgitation on follow-up examination in two cases. Our current policy in patients with uncomplicated isolated cleft involves non-invasive assessment of these children and surgical correction if the regurgitation is significant.

Diagnosis, Differential↗
PubMed1982

Pulmonary atresia and intact ventricular septum: surgical management based on a revised classification.

Sixty patients with pulmonary atresia and intact ventricular septum (PA:IVS) presenting from 1970 to 1980 are reviewed. Three groups of patient are discussed: those with tripartite right ventricles, those with no trabecular portion to the cavity, and those with neither trabecular nor infundibular portions. The decrease in early mortality for neonates with PA:IVS since 1977 (one death in 15 patients) supports our current management policy of preoperative prostaglandin E1 infusion with transpulmonary valvotomy (for patients with an infundibular cavity) combined with a left modified Blalock-Taussig shunt using a Gore-Tex prosthesis. Tricuspid valve growth, estimated by serial angiograms in 12 patients, was greater if right ventricle-to-pulmonary artery continuity was established. Later definitive repair was attempted in nine patients, with two early deaths; five underwent right ventricular outflow tract reconstruction and four had modified Fontan procedures. Neonates with critical pulmonary stenosis are also discussed. Their neonatal mortality (nine deaths in 20 patients) was similar to that of comparable patients with PA:IVS, but their actuarial survival at 5 years (55%) was superior (36% at 5 years).

Blood Pressure↗
PubMed1982

Acute infective pericarditis in infancy.

Infective pericarditis is rare; the characteristic presenting illness in 3 children, each aged under one year, is recorded. Early diagnosis is important since surgical drainage of the pericardium is often necessary in addition to antibiotic therapy. The clinical features may suggest pericarditis, but diagnosis is readily and reliably confirmed by echocardiography.

Acute Disease↗