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Biomedical subjects

V Henderson

Publications and source records attributed to V Henderson.

At least 19 recordsLinked to original sources

Angiographic yield in penetrating extremity trauma.

Indications for angiography in the evaluation of penetrating extremity trauma remain controversial. Our experience was reviewed to determine the yield of angiography in penetrating extremity trauma and to correlate clinical findings with angiographic results. During an 81-month period from 1983 through 1989, 284 extremity arteriograms were carried out in 268 patients. The angiographic yield in patients with abnormal clinical findings was 51%. The angiographic yield in patients when proximity of the injury to major vessels was the only indication was 6% (7% with gunshot wounds and 0% with stab wounds). Neurologic deficit alone as an indication for angiography accounted for 55% of the angiograms interpreted as "negative" and none of those interpreted as "positive". We conclude that the use of angiography in patients with gunshot wounds to the extremity with "proximity injuries" to major vessels should continue, its use is not warranted in extremity stab wounds when proximity is the sole indication, and abnormal neurologic findings in the absence of other findings are a poor predictor of vascular injury.

Adolescent

Linkage to Tourette syndrome is excluded for red-cell acid phosphatase (ACP1) and flanking markers on chromosome 2pter-2p23.

A recent linkage study of Tourette syndrome with markers in the distal region of chromosome 2p gave a contradictory result with red-cell acid phosphatase (ACP1) compared to the nearby anonymous DNA markers. A modifier gene that is suspected of leading to reduced penetrance of the gene that causes the degenerative neurologic disorder Joseph disease has been hypothesized to lie on chromosome 2p25 near the ACP1 locus. Because Tourette syndrome (TS) has also been shown to have reduced sex-specific penetrance, ACP1 typings were performed on 12 families segregating TS, and pair-wise linkage analysis was carried out. Linkage was excluded for nearly 15 cM on either side of the ACP1 locus. Unpublished exclusion data from several laboratories permit exclusion of a linkage group extending from 2pter to 2p23. Furthermore, no support for the presence of any type of modifier of TS gene expression could be seen in these data.

Acid Phosphatase

Lung dust analysis in the assessment of past exposure of man-made mineral fibre workers.

In the cohort of American MMMF workers reported by ENTERLINE et al. [Ann. occup. Hyg. 31, 625-656 (1987)] autopsies were recorded in 652 (13.5%) of 4840 deaths. Lung tissue samples were sought from all pathologists and obtained in 145 (22.2%), together with similar samples from 124 matched referents. Lung fibre counts by phase contrast microscopy were 60% higher (P less than 0.05) in workers than referents. Electron microscopy (ATEM) also showed more fibres of all kinds--MMMF, asbestos and other--but no convincing excess of any one type. Lung samples of only 26% of workers contained any MMMF, almost all siliceous in nature and in low concentration. There were too few cases of lung cancer (19) for any useful conclusion; however, in the plant with the highest lung cancer SMR (200), and a probable mesothelioma, amosite at greater than 1.0 fibres per micrograms (f micrograms-1) was found in four of six workers but in none of their matched referents. Although our findings contribute little to the interpretation of the results obtained by ENTERLINE et al. they indicate the potential value of tissue analyses in monitoring epidemiological studies of MMMF exposure.

Cohort Studies

Mortality of workers potentially exposed to epichlorohydrin.

An epidemiological study was undertaken to determine whether the animal carcinogen, epichlorohydrin (ECH), produces cancer in man. A total of 863 workers with probable exposure to ECH at two chemical plants during 1948-65 were followed up for deaths up to 1983. Twenty years or more after first exposure the all cancer SMR was 112.2 (22 deaths) and the SMR for leukaemia was 500.0 (three deaths), which is statistically significant. All cancer, leukaemia, and most other causes of death were related to estimated levels of exposure to ECH, except violence. The most consistent (both plants) relation was between exposure level and heart disease. Overall, the heart disease SMR 20 years or more after first exposure was 39.2 (five deaths) for low exposure and 105.4 (17 deaths) for high exposure. Limited evidence of a cardiovascular disease relation to ECH production in one other epidemiological study is supported by this study. Allyl chloride used in the production of ECH may play a part. The relation of heart disease and exposure does not appear to be an artifact, although the fact that many other causes of death were also related to exposure argues against a causal relation.

Cardiovascular Diseases

Excellence in nursing. 1969.

We talk a great deal about excellence in nursing and commit ourselves to this quality in stated philosophies and goals. When it comes to defining or measuring excellence, however, a variety of views emerge. In this article, a nurse--one who is universally considered among the excellent because of her inspired teaching, her many-faceted contributions to nursing philosophy and literature, and her abiding concern for patient care--describes her personal concept of excellence.

Education, Nursing

Visual evoked potentials in dementia: a meta-analysis and empirical study of Alzheimer's disease patients.

A meta-analytic review of flash and pattern reversal visual evoked potential research indicates that elderly demented patients have longer P100 latencies than age-matched control subjects. In the present empirical research, patients with research diagnoses of probable Alzheimer's disease were compared with sex- and age-matched control subjects using P100 latencies of visual evoked potentials (VEP) elicited by flash and pattern reversal. As compared to control subjects, Alzheimer's disease patients showed significantly longer P100 latencies of the VEP elicited by pattern reversal; the flash P100 only marginally distinguished them. These findings are discussed within the context of VEP recording practices, patient selection, sex and age matching of control subjects, and the visual system.

Aged

Development of NADPH diaphorase-positive pedunculopontine nucleus neurons.

Nicotinamide adenine dinucleotide phosphate (NAD-PH) diaphorase histochemistry was used to localize cholinergic neurons in the pedunculopontine nucleus of neonatal and adult rats. Measurements of cell body areas revealed an average area around 200 microns2 at birth, followed by a significant increase to approximately 500 microns2 by 2 weeks of age. Thereafter, there was a decrease in cell area such that by 5 weeks of age the neurons had attained their adult size of around 300 microns2. The marked increase in cell size at the end of 2 weeks of age is discussed in relation to significant events in the development of locomotor and other rhythmic function control systems.

Aging

Effect of tetrahydrouridine on the clinical pharmacology of 1-beta-D-arabinofuranosylcytosine when both drugs are coinfused over three hours.

When 1-beta-D-arabinofuranosylcytosine (ara-C), 25 mg/m2, is infused over 3 h together with tetrahydrouridine (THU) at 10 to 350 mg/m2 to heavily pretreated patients with solid tumors, Michaelis-Menten type kinetic values are observed with leveling off of delta area under the curve, delta ara-C levels at 3 h, and delta total body clearance after 150 mg/m2 of THU. When the ara-C dose was increased to 50, 75, and 100 mg/m2 coinfusion of 250 or 350 mg/m2 of THU significantly increased plasma ara-C at peak and area under the curve. In contrast, total body clearance and volume of distribution decreased significantly. At 100 mg/m2 of ara-C coinfused with high doses of THU, i.e., at 350 mg/m2, the pharmacokinetics of plasma ara-C was changed from a biphasic decay of plasma ara-C at peaks (control) to a curve similar or identical to a monophasic curve, indicating that THU not only inhibits deamination but also changes the distribution of ara-C. This combination provides plasma ara-C levels (greater than or equal to 10 microM) comparable to high dose ara-C at 1 g/m2. Such plasma ara-C levels are considered to be sufficient for saturation of the kinases catalyzing the production of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate. This reduced ara-C dose necessary to achieve saturation of kinases also reduces plasma 1-beta-D-arabinofuranosyluracil levels substantially. Toxicity of this combination was predominantly confined to bone marrow and gastrointestinal toxicity.

Adult

Direct methods of obtaining information on cigarette smoking in occupational studies.

Many occupational epidemiology studies require complete and accurate information on tobacco use to control for confounding by smoking and to assess interactions of smoking with workplace exposures. This paper reviews and evaluates the availability, reliability, validity, and efficiency of the various data sources and techniques for obtaining individual smoking data, including existing records, biological markers, and surveys. Emphasis is placed on the highly problematic issue of obtaining retrospective smoking histories. In general, the survey technique is currently deemed the most feasible approach for obtaining lifetime smoking histories. Both theoretical and practical aspects of smoking surveys are discussed in detail and are illustrated with a review of the recent literature and with data from two recent retrospective cohort studies conducted at the University of Pittsburgh. Several recommendations involving both the use of smoking data and areas for future methodologic research are presented. These include (1) justification for collecting smoking data in occupational studies based primarily on the potential for smoking to act as an effect modifier rather than solely as a confounder, (2) checks for reliability and validity in all studies which involve the collection of smoking data, (3) more methodologic research to better understand the impact that missing, unreliable, and invalid smoking data may have on the ability to detect and quantify important smoking-exposure interactions, and (4) an assessment of the correlation between biological markers and cigarette carcinogen exposure.

Epidemiologic Methods

Asbestos and cancer: a cohort followed up to death.

The mortality experience of 1074 white men who retired from a United States asbestos company during the period 1941-67 and who were exposed to asbestos working as production and maintenance employees for the company is reported to the end of 1980 when 88% of this cohort was known to be dead. As noted in earlier reports the mortality for respiratory and gastrointestinal cancer was raised. A more detailed examination of causes of death shows that the excess in gastrointestinal cancer was largely due to a statistically significant excess in stomach cancer. A statistically significant excess was also noted for kidney cancer, cancer of the eye, and non-malignant respiratory disease. Eight deaths from malignant mesothelioma were observed, two of which were peritoneal. Asbestos exposures for these mesothelioma cases were low relative to other members of the cohort. Continuing follow up of this cohort shows a dose response relation for respiratory cancer that has become increasingly linear. Standardised mortality ratios peaked 10 to 15 years after retirement and were relatively constant at around 250 in each five year interval starting in 1950. This excess might have been detected as early as 1960 but certainly by 1965. The mortality experience of this cohort reflects the ultimate effects of asbestos since nearly all of the cohort has now died.

Aged

The influence of cataract types on potential acuity meter results.

The records of 100 patients who had cataract surgery were reviewed to compare preoperative potential acuity meter (PAM) results with postoperative visual acuity. A PAM acuity was obtainable in 95 patients. In 82 of the 95 patients (86%), the PAM levels were within three lines of the outcome. Potential acuity meter results substantially lower (less than or equal to four Snellen lines) than outcome generally occurred when posterior subcapsular (PSC) or PSC plus diffuse cortical or nuclear changes were present. We believe that the PAM projection can usually go around or through the nuclear sclerosis to give an accurate prediction. However, with PSC or mixed type, one may not always find a window in the cataract. Also, PSC or diffuse cortical cataracts may be particularly disruptive to the paracentral diffracted light that is an important factor in PAM acuity.

Cataract Extraction