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Biomedical subjects

D L McGee

Publications and source records attributed to D L McGee.

At least 55 records · Page 3Linked to original sources
PubMed1991

Induction of skin tanning by subcutaneous administration of a potent synthetic melanotropin.

UNLABELLED: OBJECTIVE--To determine the efficacy of short-term administration of a synthetic analogue of alpha-melanotropin, [Nle4D-Phe7] (NDP)-alpha-melanocyte-stimulating hormone (MSH), in darkening (tanning) human skin. DESIGN--Randomized, placebo-controlled, double-blind clinical trial. SETTING--Clinical research unit of a university medical center. SUBJECTS--Twenty-eight healthy white men with a history of either poor tanning (skin type I or II) or good tanning (skin type III or IV) recruited from advertisements and paid to participate in the study. METHODS--Each subject received 10 subcutaneous injections of either a purified NDP preparation or saline over 12 days. They were followed up for 7 weeks after therapy was completed. All subjects used a high-potency sunscreen during the trial. MAIN OUTCOME MEASURE--Skin darkening was quantified by serial chromaticity measurements prior to, during, and after therapy. RESULTS: -A significant parabolic curve of skin darkening activity was noted in subjects with skin type I or II (P less than .001) and with skin type III or IV (P much less than .001) who were given NDP. No darkening occurred in the subjects who were given a placebo. Peak changes were seen 1 to 3 weeks after therapy was completed. CONCLUSION--Human skin darkens as a response to a synthetic melanotropin given by subcutaneous injection. Skin tanning appears possible without potentially harmful exposure to ultraviolet radiation.

Adult↗
PubMed1991

Cytogenetic profile of 109 lipomas.

Cytogenetic analysis of short-term cultures was carried out on 109 lipomas from 92 patients. Clonal chromosomal abnormalities were present in 50% of the tumors analyzed. Based on the results, three main cytogenetic groups were identified and included: (a) tumors with normal karyotypes, (b) tumors with abnormalities involving region q13-15 on chromosome 12, and (c) tumors with other clonal aberrations. Within each of these groups, cytogenetic subgroups could be identified, each characterized by a specific anomaly. Tumors with abnormalities of 12q included specific subgroups with t/ins(1;12)(p32-33;q13-15), t(2;12)(p21-22;q13-14), t(3;12)(q28;q14), t(12;21)(q13;q21), complex, and nonrecurrent aberrations. The group containing heterogeneous clonal aberrations included subgroups with del(13)(q12q22), der(6)(p21-23), der(11)(q13), and nonspecific aberrations. Chromosome bands 1p36, 1p32-33, 2p21-22, 3q27-28, 6p21-23, 11q13, 12q13-15, 13q12, 13q22, 17p13, 17q21, and 21q21-22 were preferentially involved in structural rearrangements in lipomas. The identification of these sites of nonrandom rearrangements may serve to identify genes (at or near the junctions of chromosomal aberrations) involved in normal cellular growth control. Statistical analysis of the data revealed a correlation among karyotypic abnormalities and clinical data, such as age and sex of the patient, and tumor depth, site, and size.

Chromosome Aberrations↗
PubMed1990

Relation of cytogenetic abnormalities and clinical outcome in metastatic melanoma.

The value of chromosomal analysis is well established in human hematologic neoplasms. In contrast, the relation between chromosomal abnormalities and clinical outcome in solid tumors in humans has received little study. We undertook this study to determine whether chromosomal abnormalities could provide information on the survival of patients with malignant melanoma. Chromosome-banding analysis was performed on tumor-biopsy samples from 62 patients with metastatic melanoma, and recurring cytogenetic abnormalities were correlated with survival. Patients with structural abnormalities of chromosome 7 or 11 had significantly shorter survival than patients without these abnormalities. We conclude that cytogenetic analysis may provide useful prognostic information about patients with metastatic melanoma.

Chromosome Aberrations↗
PubMed1990

Quantitation of vitamin K in human milk.

A quantitative method was developed for the assay of vitamin K in human colostrum and milk. The procedure combines preparative and analytical chromatography on silica gel in a nitrogen atmosphere followed by reversed phase high performance liquid chromatography (HPLC). Two HPLC steps were used: gradient separation with ultraviolet (UV) detection followed by isocratic separation detected electrochemically. Due to co-migrating impurities, UV detection alone is insufficient for identification of vitamin K. Exogenous vitamin K was shown to equilibrate with endogenous vitamin K in the samples. A statistical method was incorporated to control for experimental variability. Vitamin K1 was analyzed in 16 pooled milk samples from 7 donors and in individual samples from 15 donors at 1 month post-partum. Vitamin K1 was present at 2.94 +/- 1.94 and 3.15 +/- 2.87 ng/mL in pools and in individuals, respectively. Menaquinones, the bacterial form of the vitamin, were not detected. The significance of experimental variation to studies of vitamin K in individuals is discussed.

Adult↗
PubMed1990

Estimating the number of suicides among Vietnam veterans.

Unconfirmed reports that 50,000 or more Vietnam veterans have committed suicide give the impression that these veterans are at exceedingly high risk of suicide compared with other veterans and nonveterans of the same age. On the basis of projections from two population-based mortality studies, the authors estimate that fewer than 9,000 suicides occurred among all Vietnam veterans from the time of discharge through the early 1980s. The sixfold or greater relative risk of suicide implied by the unsubstantiated suicide death tolls is also demonstrated to be incompatible with the findings of epidemiologic studies of mortality risk among Vietnam veterans.

Adult↗
PubMed1989

A mechanism for the development of fixed primary (essential) hypertension: insights from population-based studies using echocardiography.

Two recent observations based on echocardiographic studies in large population-based studies may have far-reaching implications: The concentric form of left ventricular hypertrophy emerges prominently in white Framingham (MA) men aged 40-49 years, and ten years later in white Framingham women. This parallels the pattern of emergence of fixed primary hypertension in white Framingham adults. Normotensive black teenage boys in Bogalusa have an echocardiographic profile that parallels more closely the profile of middle-aged white Framingham men and women than white teenage boys and girls. As noted, the former echocardiographic profiles are strongly associated with fixed primary hypertension in older adults and may be the harbingers of the premature development of fixed primary hypertension in the young black boys. These findings fit into a chain of observations that: (1) give new insight into the mechanism for premature development of primary hypertension and that should ultimately lead to closing the loop needed to characterize the cause of such hypertension: (2) may ultimately help to explain the excess of premature cardiovascular, renal, and cerebrovascular morbidity and mortality in the U.S. black population compared with the white population; and (3) may lead to new, more effective strategies for reducing such excess morbidity and mortality.

Adolescent↗
PubMed1989

A model for comparison of left ventricular mass and systolic blood pressure as risk factors for stroke.

Electrocardiographic left ventricular hypertrophy (increased left ventricular mass) is a known risk predictor of stroke independent of blood pressure level. However, electrocardiography is an insensitive index of such hypertrophy. To assess the potential risk associated with increased left ventricular mass via continuous measurement (as is becoming available with echocardiography), published longitudinal data from the Framingham study were used to estimate risk of stroke associated with various levels of increased left ventricular mass. This model predicts that left ventricular mass is at least as powerful as, if not more powerful than, systolic blood pressure levels for predicting risk of stroke.

Cardiomegaly↗
PubMed1989

New perspectives on left ventricular hypertrophy: anatomy, physiology, and significance.

The advent of echocardiography has added an important and sensitive tool for assessment of left ventricular hypertrophy (increased left ventricular mass). Recent echocardiographic studies in large population-based samples suggest an epidemic of left ventricular hypertrophy. Preliminary data suggesting important prognostic importance for such left ventricular hypertrophy (independent of standard risk factors) has fueled interest in the development, determinants, and other features of the hypertrophy. Hemodynamic and neurohumoral factors are the most prominent stimuli to adaptive (physiologic) myocardial hypertrophy, which can progress to maladaptive (pathologic) hypertrophy. The overall blood pressure experience, overweight, the cardiovascular response to recurrent psychosocial stress and physical activity level are four important correlates and potential determinants of left ventricular mass in various urban-suburban populations. Determination of the relative contributions and interrelations of these and other factors (such as heredity) to various forms of left ventricular hypertrophy found in various demographic groups warrants intensive investigation.

Cardiomegaly↗
PubMed1989

A model-based approach to the imputation of missing data: home injury incidences.

Missing or incomplete data cases are a problem in all types of statistical analyses. In disease surveillance, this problem inhibits determining the actual incidence of a disease event and monitoring the disease occurrence. Several statistical techniques have been developed to impute values for incomplete data cases. We present a model-based approach to the imputation of missing data elements as applied to determining the incidence of home injury deaths.

Accidents, Home↗
PubMed1989

Estimating trends in the effectiveness of seat belts in saving lives, 1975-1985.

We examine the effectiveness of seat-belt systems for preventing mortality in automobile crashes. In particular, we examine whether seat-belt effectiveness has been constant over this period and conclude that there has been a trend toward an increased effectiveness of seat-belt systems. The relative odds of death associated with wearing seat belts dropped from 0.80 in 1975 to 0.34 in 1985. This trend results from improvements in both the type and design of seat belts and from additional design changes, such as padded dashboards and collapsible steering columns, that protect occupants at the time of collision.

Accidents, Traffic↗
PubMed1989

Is coffee consumption a contributor to cardiovascular disease? Insights from the Framingham Study.

Reported coffee consumption during 1954 to 1958 and 1971 to 1973 was used to test for association with cardiovascular disease (CVD) incidence and lipid values in the Framingham cohort. Multivariate analysis was employed, regressing CVD on age, systolic pressure, cigarette use, body mass index, total cholesterol, and coffee intake. In pooled analyses (2648 men with 549 CVD cases and 3566 women with 462 CVD cases) coffee intake was not associated with CVD incidence in either smokers or nonsmokers, irrespective of sex. Similarly, multivariate analyses for individuals with existing cardiovascular disease showed no association between coffee intake and subsequent cardiovascular disease. In men significant negative associations between coffee and total cholesterol, and very-low-density lipoprotein cholesterol were seen, whereas in women positive associations with low-density lipoprotein cholesterol were observed. Although inconsistent effects on the lipid profile were seen, no increase in primary or secondary CVD was seen with coffee drinking.

Adult↗
PubMed1987

Nonspecific electrocardiographic abnormality as a predictor of coronary heart disease: the Framingham Study.

The risk of developing overt coronary heart disease is examined in relation to occurrence of non-specific electrocardiographic S-T and T-wave abnormalities (NSA-ECG) in the Framingham Study. In the course of follow-up, 14% of the 5127 men and women had or developed NSA-ECG without clinically apparent intervening coronary heart disease. During 30 years of surveillance, 760 men and 578 women developed a first overt clinical manifestation of coronary heart disease. NSA-ECG appears to be a hallmark of a compromised coronary circulation which predicted the occurrence of every clinical manifestation of coronary heart disease independently of known risk factors including hypertension, its chief determinant. Coronary morbidity and mortality was increased twofold in each sex. The more common T-wave abnormality alone carried a significant increased risk, although the combination of S-T and T-wave seemed most hazardous. Persons who develop NSA-ECG without other explanation warrant vigorous preventive management against coronary heart disease.

Adult↗
PubMed1987

Reduction of hypertension-associated heart disease and stroke among black Americans: past experience and new perspectives on targeting resources.

Over the past two decades, national hypertension-control programs and policies have focused on early diagnosis and management. Measured by intermediate results--such as percentages of cases now taking medication--these efforts have been markedly successful, especially among black hypertensives. The ultimate measure of success--reduction in hypertension-associated disease and death--must address the one-third excess prevalent among blacks. Biologic and age-specific variables in diagnosis and treatment must be accommodated. Future gains in efficient use of resources and equity in outcome will require use of new technologies and models of targeting.

Adult↗
PubMed1987

Composite scoring--methods and predictive validity: insights from the Framingham Study.

After three decades of epidemiologic research at Framingham and elsewhere, the risk factor concept is now firmly established. Atherosclerotic cardiovascular disease can now be predicted and highly vulnerable candidates identified from profiles derived from ordinary office procedures and simple laboratory tests [1]. Risk can be estimated over a 20--30-fold range, and close to half of the cardiovascular events are found to occur in a tenth of the population at highest multivariate risk. Categorical risk assessments focusing on the number of "risk factors" present also identify high-risk subjects but tend to overlook high-risk individuals with multiple marginal abnormalities. Multivariate cardiovascular risk profiles made up of the major cardiovascular risk factors can predict all of the major cardiovascular events, even in advanced age, with reasonable efficiency. Such multivariate risk assessments can be made convenient by reproduction of handbooks and use of small programmed calculators, software for personal computers, and slide rules to facilitate office and public health assessments. The sensitivity and specificity of these risk profiles can probably be improved by more detailed lipid information, including HDL-cholesterol [12], vital capacity determination, and other ECG abnormalities. General cardiovascular risk profiles can be devised to predict efficiently all of the major cardiovascular events.

Adult↗
PubMed1986

A program for logistic regression on the IBM PC.

Logistic regression is one of the most frequently used tools of epidemiologic analyses. This paper describes a program to accomplish interactive logistic analysis on the IBM PC and compatibles by using the disk operating system. The program provides most statistics of interest to epidemiologists, including confidence intervals for estimated coefficients and estimated odds ratios.

Computers↗
PubMed1985

Hyperuricemia as a risk factor of coronary heart disease: The Framingham Study.

Uric acid values were obtained on subjects of the original Framingham cohort at their fourth and 13th biennial examinations. The mean uric acid value for men was 5.0 mg/dl at the fourth examination and 5.7 mg/dl at examination 13 and was 3.9 mg/dl and 4.7 mg/dl, respectively, for women. This secular trend was due to both "laboratory drift" and increasing use of diuretics. Serum uric acid values were consistently higher in subjects of both sexes who were taking antihypertensive drugs at both examinations. Serum uric acid values correlated with systolic and diastolic blood pressure in both sexes; the relationship was stronger in women than in men and for systolic than for diastolic pressure. Correlations were stronger at examination 4 than at examination 13 when more antihypertensive treatment was used. Examination 4 serum uric acid predicted the subsequent development of coronary heart disease, in general, and myocardial infarction, in particular, but not angina pectoris. The uric acid relationship with myocardial infarction was equally strong in both sexes, even correcting for antihypertensive treatment. However, in multivariate analysis, including age, systolic blood pressure, relative weight, cigarette smoking, and serum cholesterol, serum uric acid did not add independently to the prediction of coronary heart disease.

Age Factors↗