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Biomedical subjects

G Howard

Publications and source records attributed to G Howard.

At least 145 records · Page 8Linked to original sources
PubMed1991

Correlations between urinary nicotine or cotinine and urinary mutagenicity in smokers on controlled diets.

Cigarette smokers have been reported to void urine that is more mutagenic, as measured in the Salmonella/microsome assay, than urine voided by nonsmokers. Several previous studies have attempted to correlate indices of tobacco smoke exposure (e.g. nicotine, cotinine, tar intake) with urinary mutagenicity, with conflicting results. These studies generally involved small numbers of smokers and did not carefully control diet, which is known to affect urinary mutagenicity markedly. Our objective was to conduct a controlled study to determine clearly if there were a correlation between urinary nicotine, cotinine, or nicotine + cotinine and urinary mutagenicity and to determine if nicotine or its major metabolite plays a role in the mutagenicity of urine from cigarette smokers. We used a large number of smokers (31), each of whom smoked both a tobacco-burning cigarette and a tobacco-heating cigarette on consecutive weeks, and we prepared and served identical diets to all subjects. Nicotine and cotinine concentrations were determined in small aliquots from urine samples collected over 24 hr, and the remaining urine sample was extracted and concentrated on XAD-2 resin for mutagenicity assays in the Salmonella/microsome test. Nicotine, cotinine, and nicotine + cotinine were statistically correlated with mutagenicity of urine from smokers of the tobacco-burning cigarette, but there was no correlation between nicotine, cotinine, or nicotine + cotinine and mutagenicity of urine from smokers of the tobacco-heating cigarettes. Thus, although urinary nicotine and cotinine concentrations correlate with urinary mutagenicity in smokers of tobacco-burning cigarettes, the present results indicate that nicotine and its metabolite are not responsible for the mutagenicity of smokers' urine.

Cotinine↗
PubMed1991

The community hospital-based stroke programs in North Carolina, Oregon and New York--V. Stroke diagnosis: factors influencing the diagnostic evaluation of patients following acute stroke.

Among the 4129 patients of the Community Hospital-based Stroke Program, 30% had an unspecified stroke diagnosis. Since specific diagnosis and, perhaps, eventual treatment, derives in part from diagnostic testing, we examined the effect of clinical condition, geographic and demographic factors on the incidence of certain diagnostic tests after acute stroke. In this multivariable analysis, race, sex, history of hypertension and history of diabetes did not influence the chance of having any test, but older age strongly reduced the chances of receiving extensive evaluation. When CT scanning was available, the utilization of a CT as well as other diagnostic studies including cerebral angiography, radionuclide brain scan, EEG and EKG was increased. The odds of receiving a CT scan increased if the patient was married, and decreased with a history of previous stroke. A history of previous TIA increased the chance of having a cerebral angiogram while a history of cardiac disease decreased the chance. There were striking regional geographic differences in the use of CT, radionuclide brain scanning and cerebral angiography which may, in part, reflect differences between the availability of these technologies in urban and rural hospitals. These results indicate that evaluation of stroke patients remains heterogenous.

Aged↗
PubMed1991

Transactivation of pancreas-specific gene sequences in somatic cell hybrids.

Enhancer/promoter elements from two pancreas-specific genes, those encoding amylase and elastase, were ligated to the bacterial GPT gene. The resulting construct can be used to select for expression of gene products which activate these pancreas-specific promoters in hybrid cells. The selectable GPT construct was stably transferred into several cell lines either directly or by cotransfection with pSV2Neo. GPT was expressed when transferred to pancreatic cell lines but not when transferred to GPT-fibroblast (L) cells or hepatoma cells. When the transformed L cells and hepatoma cells were fused with pancreatic cell lines, GPT was activated in the hybrid cells. Endogenous pancreas-specific genes from the L-cell and hepatoma parents were also activated in the hybrids. In addition, a pancreas-specific nuclear protein, PTF1, was produced in pancreatic and hybrid cells, correlating with GPT expression. The transformed L cells and hepatoma cells thus contained a nonexpressed construct which could be activated in trans by factors present in pancreatic cells. The hepatoma hybrid also continued to produce albumin, demonstrating the coexpression of liver and pancreas-specific genes in the hybrid-cell population. Cell lines carrying the amylase/elastase/GPT construct may be useful as a selection system for cloning of pancreatic transcription activators.

Albumins↗
PubMed1991

Relationship of hospitalized stroke rate and in-hospital mortality to the decline in US stroke mortality.

Data from the National Hospital Discharge Survey was used to estimate the admission rate and in-hospital mortality for US stroke patients from 1970 to 1987. Over this period the hospital admission rate increased from 5.0 per 1,000 population to 5.5 per 1,000, while the in-hospital mortality fell from 18.6 to 10.0% of discharges. When patients experiencing general or late effects or transient ischemic attacks were excluded, the hospital admission rate increased from 2.8 to 4.8 per 1,000 and in-hospital mortality fell from 26 to 12% of discharges. Admission rates increased from 1970 to 1987 for both hemorrhagic strokes and cerebral infarctions, but fell for ill-defined cerebrovascular events, presumably reflecting increased use of computed tomography and magnetic resonance imaging during this period. Mortality for hemorrhagic strokes decreased from 45 to 30% of discharges, mortality for infarctions decreased from 24 to 13% and mortality for ill-defined events fell from 24 to 17%. There are several limitations with the use of the National Hospital Discharge Survey data to estimate changes in hospital admission rates and in-hospital mortality. However, these data suggest a greater role for decreasing case fatality in explaining nationwide declines in stroke mortality rates than has generally been acknowledged.

Acute Disease↗
PubMed1991

Cerebral infarction verified by cranial computed tomography and prognosis for survival following transient ischemic attack.

Of 564 consecutive patients with transient ischemic attack, 350 (62%) had cranial computed tomography performed. Except for date of admission and smoking history, there were few differences between the patients evaluated with computed tomography and the 214 who were not. Cerebral infarcts were found in 59 (17%) of the 350 tomographic evaluations. Previous clinically diagnosed stroke, older age, and male sex were all significantly associated with the occurrence of tomographically verified infarcts (p less than 0.05). After controlling for stroke history and other important covariates, patients with tomographically verified infarcts had significantly shorter survival times than did patients without evidence of infarction on computed tomography (p = 0.035). Thus, cranial computed tomography findings appear to have important prognostic value for estimating survival following transient ischemic attack.

Cerebral Angiography↗
PubMed1991

Reevaluation of transient ischemic attacks as a risk factor for early mortality.

The prevailing belief that transient ischemic attack is a risk factor for cardiovascular morbidity and mortality is based primarily on comparisons of survival of patients after transient ischemic attacks to that of an age-, race-, and sex-adjusted general population. Concomitant conditions that carry a high risk of premature mortality or morbidity, such as ischemic heart disease, hypertension, and diabetes, are very prevalent among patients with transient ischemic attacks. Hence, the poor prognosis of such patients may be attributable to these factors rather than their transient ischemic attack per se, which may only serve to bring patients into the medical system. We compared the survival of 336 patients after transient ischemic attack to that of a control group with a similar risk factor profile consisting of 6,710 patients evaluated for cardiac catheterization. Survival estimates, both unadjusted and adjusted for risk factors, did not differ between the two groups. Three-year survival estimates, after adjustment to the mean value of covariates, were 94% for the patients with transient ischemic attacks and 91% for the controls. These results suggest that the transient ischemic attack may not be an independent risk factor for mortality, although it may identify patients already at increased risk from coexisting conditions.

Cardiac Catheterization↗
PubMed1991

Medical reports and the law.

Over the past few months several serious and potentially disturbing cases have been raised by occupational health nurses concerning their employers' requests for access to or control over the medical records of their employees. In this, the first of two articles, Gillian Howard examines the legal and ethical issues surrounding the keeping, obtaining and disclosure of medical records and reports.

Confidentiality↗
PubMed1991

Vicarious liability of employers explained.

The law on vicarious liability was brought sharply into focus in July when the Court of Appeal reviewed the liability of an employer for the actions of an employee in a contempt of court action. Gillian Howard looks at some recent cases and offers useful advice on how companies can avoid liability in future.

Employment↗
PubMed1991

Pregnancy discrimination: European court rulings.

1 Dismissal for pregnancy, childbirth or absence on maternity leave is automatically in breach of the Equal Treatment principle without having to consider what treatment would have been given to a man. Any public sector employees may enforce this principle against their employers without any service qualification (so said the ECJ in Foster -v- British Gas [1990] IRLR 353). Employees in the private sector, must rely on the Sex Discrimination Act or Section 60 of the Employment Protection (Consolidation) Act 1978. But the latter case requires two years' service. 2 The UK leaves itself open to infringement proceedings for inadequate implementation of the requirements of the Directive. 3 Tribunals and courts in the United Kingdom are bound to follow these two decisions in any future similar cases.

Civil Rights↗