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Biomedical subjects

H L Taylor

Publications and source records attributed to H L Taylor.

At least 19 recordsLinked to original sources
PubMed1989

HIV infection in England and Wales: a changing pattern.

Of 32,983 specimens from 307 sources in England and Wales tested in the Virus Reference Laboratory for anti-HIV between 1984 and 1987, 6491 (20%) were positive. Ninety-five per cent of the positive subjects were male and 44% of them were from three London genito-urinary medicine clinics. In 1987 the numbers of newly diagnosed HIV infections decreased in homosexual men and haemophiliacs and increased in injecting drug abusers; 148/1199 (12%) of all the positive findings in 1987 were in females. Between 1984 and 1987 the proportion of anti-HIV positive individuals who were asymptomatic fell by nearly 10% and the proportion with AIDS/ARC rose by nearly 10%. Of the requests leading to positive results 1280 (20%) were recognized as duplicates of previous positive results, while for 34% of the requests no clinical information was provided. These deficiencies in the data compromise HIV surveillance based on diagnostic testing, and supplementary bias-free data are needed.

Adolescent↗
PubMed1989

Leukaemia and residence near electricity transmission equipment: a case-control study.

A population-based case-control study of leukaemia and residential proximity to electricity supply equipment has been carried out in south-east England. A total of 771 leukaemias was studied, matched for age, sex, year of diagnosis and district of residence to 1,432 controls registered with a solid tumour excluding lymphoma; 231 general population controls aged 18 and over from one part of the study area were also used. The potential for residential exposure to power frequency magnetic fields from power-lines and transformer substations was assessed indirectly from the distance, type and loading of the equipment near each subject's residence. Only 0.6% of subjects lived within 100 m of an overhead power-line, and the risk of leukaemia relative to cancer controls for residence within 100 m was 1.45 (95% confidence interval (CI) 0.54-3.88); within 50 m the relative risk was 2.0 but with a wider confidence interval (95% CI 0.4-9.0). Over 40% of subjects lived within 100 m of a substation, for which the relative risk of leukaemia was 0.99. Residence within 25 m carried a risk of 1.3 (95% CI 0.8-2.0). Weighted exposure indices incorporating measures of the current load carried by the substations did not materially alter these risks estimates. For persons aged less than 18 the relative risk of leukaemia from residence within 50 m of a substation was higher than in adults (PR = 1.5, 95% CI 0.7-3.4).

Electromagnetic Fields↗
PubMed1979

Effect of submaximal exercise on vulnerability to fibrillation in the canine ventricle.

The risk of instantaneous death due to ventricular fibrillation was compared in resting and exercised dogs. Three weeks before testing, all dogs had bipolar left ventricular stimulating electrodes implanted and a reversible snare was placed around the anterior descending coronary artery. The dogs were randomly assigned to either an exercise (13 dogs) or a control (12 dogs) group. We measured ventricular fibrillation thresholds (VFTs) in all dogs before and after inducing ischemia by tightening the snare while the dogs stood at rest. The next day, nonischemic and ischemic VFTs were redetermined for control dogs at rest and for the exercise group during a treadmill run. No statistically significant changes were noted within and between groups in nonischemic or in ischemic VFTs at rest. In five exercise dogs, spontaneous ventricular fibrillation occurred during the first 8 minutes of the ischemic run, For the eight other exercise dogs, running increased the mean drop in VFTs during coronary occlusion by 23% (p less than 0.01). These data suggest that moderate dynamic exercise may greatly enhance the risk of ventricular fibrillation and sudden death in the presence of myocardial ischemia. In the absence of ischemia, exercise does not appear to increase vulnerability to ventricular fibrillation.

Animals↗
PubMed1978

A method for assessing volunteer bias and its application to a cardiovascular disease prevention progamme involving physical activity.

Studies of chronic disease may require long-term observation of volunteer participants. This is a characteristic of investigations of primary or secondary prevention of cardiovascular disease by increased level of physical activity. Activation of sedentary, middle-aged, high risk men requires a substantial personal commitment on their part to a long-term programme. Because of self-selection, individuals who volunteer for such programmes cannot be assumed to be representative of the populations from which they come. To the best of our knowledge, there has been no systematic investigation of such self-selection based upon a study designed for that purpose. We found little consistent tendency for vouunteering behaviour to be associated with serum cholesterol, blood pressure, relative weight, level of activity at work, or Type A hehaviour variables.

Adult↗
PubMed1977

Acute ethanol poisoning: a two-year study of deaths in North Carolina.

A 24-month study of fatalities in North Carolina with high blood ethanol levels (300 mg/100 ml or over) revealed 502 cases with either acute alcoholism or the effects of this range of blood ethanol concentration having caused or contributed to death. This investigation reassessed the criteria for ethanol poisoning, including its cause and manner of death, and revealed recurrent patterns common to this syndrome. This inquiry also contrasted the frequency of ethanol poisoning in different areas of the country.

Acute Disease↗
PubMed1976

Chronic measurement of epidural pressure with an induction-powered oscillator transducer.

An induction-powered oscillator transducer (IPOT) was designed for the chronic measurement of epidural pressure. The transducer was completely implantable so all pressure measurements were made through the intact skin. The IPOT had a linear pressure range from -50 to +200 cm H2O, was sensitive to 1 mm H2O and had a zero drift of less than 1 mm H2O/day under full load. Zero drift was minimized by using a hermetically-sealed metal bellows transducing element which was chemically treated to prevent corrosion and creep. The correlation between epidural pressure and intraventricular pressure was determined during the first 24 hours after implantation in six dogs. Epidural pressure was found to be a linear function of intraventricular fluid pressure. Epidural pressure and intraventricular pressure were essential equal provided the epidural wedge pressure was minimized by proper insertion of the transducer. The correlation between epidural pressure and intraventricular pressure was determined after chronic implantation in five dogs. Epidural pressure was a linear function of intraventricular pressure in the chronically implanted dogs, but epidural pressure was not equal to intraventricular pressure. After chronic implantation, the epidural pressure transducer was not responsive to changes in intraventricular pressure because of mechanical changes in the dura. The dura became stiff and non-compliant. Maximum correlation between epidural pressure and intraventricular fluid pressure in chronic implantations will depend on judicious material selection and mechanical design at the transducer-dura interface.

Animals↗
PubMed1975

Vascular access for hemodialysis by bovine graft arteriovenous fistulas.

A technique has been developed for vascular access in chronic dialysis using bovine graft arteriovenous fistulas in the forearm. Indications for use of bovine arteriovenous fistulas are failures of arteriovenous shunts and standard arteriovenous fistulas at the wrist or as a primary procedure in the event that arterial inflow or venous outflow are inadequate. Choice of either a straight or loop graft is dictated by the vascular anatomy. Loop grafts, orginating from the brachial artery, should be used for inflow problems; straight grafts, originating from an artery at the wrist, should be used for outflow problems. Results have been excellent in this series of 39 grafts in 36 patients observed from two months to one year with a follow-up average of six months. Ninety per cent of the grafts continue to function or functioned until successful transplantation or the death of the patient. Advantages of bovine graft arteriovenous fistulas compared with other fistulas include ease of access, high flows and decreased incidence of hematomas. The major complication has been thrombosis, and this incidence, most likely, can be decreased by more careful selection of the type of graft placement according to the vascular anatomy.

Adolescent↗
PubMed1975

Ventricular premature beats in a population sample. Frequency and associations with coronary risk characteristics.

In a large epidemiological survey, 10,880 men aged 35 to 57 years were screened for ectopic ventricular activity and estimated risk of future coronary heart disease death. A 2-minute lead I electrocardiogram (ECG) was recorded for each man, together with measurement of serum cholesterol, blood pressure, and the number of cigarettes currently smoked. Ventricular premature beats (VPB) occurred in 540 (4.96%) men; of these 459 (4.21%) were uniform, while complex forms were detected in only 7/1000 men. VPB occurring with a frequency of greater than or equal to 10 in the 2-min recording were also rare, occurring in 9/1000 men. No relation was found between the frequency of simple or complex VPB and estimated coronary risk status or between the prevalence of VPB and the individual risk factors of diastolic blood pressure, cholesterol, or cigarette smoking. There was, however, a strong positive association between VPB and the level of systolic blood pressure, and between VPB and increasing age. The lack of association between VPB and overall coronary risk status indicates that myocardial "ischemic" changes in high-risk men may not have progressed sufficiently to alter ventricular excitability or to increase the frequency of VPB.

Adult↗