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Biomedical subjects

J Howard

Publications and source records attributed to J Howard.

At least 253 records · Page 14Linked to original sources
PubMed1981

201Thallium stress myocardial imaging: an evaluation of fifty-eight asymptomatic males.

The possible value of myocardial imaging with 201thallium as a screening procedure for the detection of latent disease has not been previously shown. Fifty-eight asymptomatic men underwent exercise 201thallium imaging together with a risk score profile based on the Framingham criteria for predicting future coronary events. Six subjects (10%) developed perfusion defects compatible with myocardial ischemia. The risk score for the population with an abnormal test was 7.7 +/- 2.9%, compared to 2.0 +/- 2.2% (p less than 0.001) for those men with normal tests. Three of the subjects with abnormal scans underwent selective coronary arteriograms; all three had normal coronary arteries. During a 30-month follow-up, all individuals remained physically active and free of cardiac symptoms. Exercise myocardial imaging is not a cost-effective means of detecting coronary artery disease in an asymptomatic population and should not be used as a screening procedure.

Adult↗
PubMed1981

Protecting the scientific integrity of a clinical trial: some ethical dilemmas.

Physicians who participate in clinical trials are mandated or encouraged to adhere to fundamental conditions than enhance the scientific validity of medical research. In some situations compliance with the study protocol may threaten the delivery of optimal care and raise ethical dilemmas among the staff. Moral conflicts may occur with respect to recruitment, control groups, randomization, blind assignments, patient withdrawals, and the use of supplementary therapies that could weaken statistical power. In designing and managing clinical trials, steps can be taken to reduce the likelihood of conflict between scientific inquiry and medical practice. Special means of protecting patients in the study can be introduced. Recognizing the existence of ethical dilemmas is a necessary prelude to the quest for objective solutions.

Clinical Trials as Topic↗
PubMed1981

Misonidazole enhancement of radiation-induced growth delay in rat rhabdomyosarcoma tumours exposed to accelerated carbon and neon ions.

The response of a rat rhabdomyosarcoma tumour was assessed by measurements of radiation-induced growth delay resulting from administration of the hypoxic cell sensitizer misonidazole in combination with single and fractionated doses of X-rays and charged-particle radiation. Enhancement ratios of 1.8--2.1 were obtained following single doses of misonidazole (500 mg/kg i.p.) and 225 kV X-rays. Single doses of misonidazole with either carbon-ion or neon-ion radiation in the 4 cm extended-peak ionization region led to enhancement ratios of 1.2--1.3. When combined misonidazole (300 mg/kg i.p.) and X-ray treatments were given in four daily fractions, the enhancement ratios decreased to 1.2--1.5. However, a four-fraction schedule using either carbon-ion or neon-ion radiation in combination with misonidazole gave enhancement ratios of 1.1--1.3, which are similar to the values obtained for single-dose schedules with the sensitizer and charged-particle radiation.

Animals↗
PubMed1981

The expression and possible origins of depression in male adolescent delinquents.

The literature on adolescent delinquent behaviour and psychopathy contains the view that much of the delinquent behaviour is masking a depressive underlay, and that psychopaths may be in a chronic state of helplessness which they defend against through their anti-social behaviour. The current study examined the levels of trait depression in two groups of adolescent male offenders in a state training school. The group classified as anti-social personalities showed higher levels of trait depression than a group of first committals. The role of a perceived lack of paternal care, and, to a lesser extent, maternal over-protection emerged as the main variables explaining the variance in the trail depression scores. The quality of parental care appeared more important than continuity, with perceived affectionless control being significantly related to high trait depression scores. The importance of the mother in the development of persistent anti-social behaviour was highlighted as was the role of the father in relation to trait depression and overall delinquent development.

Acting Out↗
PubMed1981

A phase II evaluation of m-AMSA, 4'-(9-acridinylamino) methanesulfon-m-anisidide, in patients with breast cancer.

A phase II study of m-AMSA, 4'-(9-acridinylamino) methanesulfon-m-anisidide was carried out in 40 patients with metastatic carcinoma of the breast. The drug, at a dose of 120 mg/m2, was given as a single intravenous injection every 3 weeks. One patient achieved a partial remission of 4 months duration; three patients experienced minor response. This study suggests that the true major response rate of advanced breast cancer to m-AMSA given in this manner is less than 13% at the 95% confidence level.

Adult↗
PubMed1980

Chromosome findings in 2,500 second trimester amniocenteses.

We have analyzed the chromosome abnormalities found in 2,500 amniocenteses for prenatal diagnosis; 1,887 (75%) were performed because the maternal age was 34 years or more. Chromosome abnormalities were detected in 1.80% of those referred for advanced maternal age, 1.2% between ages 34 and 39 years and 4.6% 40 years and over. Of these, four occurred in women who would have been 34 years at delivery (2.9%). Trisomy 21 accounted for 50% of the chromosome abnormalities; sex chromosome abnormalities, for 25%; the remaining 25% was divided equally between trisomy 18 and partial trisomies and mosaics. Unexpected translocations were found in 0.4%, of which two-thirds were balanced and identified in one parent. The accuracy was 99.6%.

Amniocentesis↗
PubMed1980

Hospital variations in metastatic breast cancer.

Data from the tumor abstracts of 25,535 female breast cancer patients in California were analyzed to measure hospital differences in the rates of metastatic disease at diagnosis. For white patients the metastatic rates varied from 38 to 68 per cent as hospital affiliation varied, and for blacks they ranged from 48 to 76 per cent. Tests for normality showed that the distribution of rates for white patients in private facilities was not merely due to random variation. The metastatic rates for both racial groups tended to be inversely related to the proportion of whites among the patient populations and positively related to total patient load. Hospitals affiliated with medical schools had relatively high rates for white private patients. Several explanations of the data are suggested. They consider the possible effects of patient and physician health care practices and host vulnerability to the spread of breast cancer.

Black or African American↗
PubMed1980

Dissociation between plasma triglyceride concentration and tissue lipoprotein lipase deficiency in insulin-deficient rats.

Insulin deficiency was produced by streptozotocin in young (5-6 wk old) male rats, and measurements were made of plasma triglyceride and glucose concentrations and of lipoprotein lipase (LPL) activity of adipose tissue (epididymal) and muscle (gastrocnemius and soleus). Rats with streptozotocin-induced diabetes underwent a significant reduction in adipose tissue LPL activity (both total and heparin releasable), but the fall in LPL activity in these rats bore little relationship to their rise in plasma triglyceride concentration. Furthermore, muscle LPL activity was essentially unchanged in diabetic rats. Qualitatively similar changes were observed when measurements were made at either 8 a.m. (after the normal evening access to food) or 2 p.m. (6 h after food withdrawal). It is concluded that the hypertriglyceridemia that occurs secondary to insulin deficiency is not a simple function of decreased tissue LPL activity.

Adipose Tissue↗