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Biomedical subjects

H E McKean

Publications and source records attributed to H E McKean.

At least 19 recordsLinked to original sources
PubMed1991

Polymorphisms in oxidative drug metabolism: relationship to food preference.

To determine whether a correlation exists between polymorphisms of oxidative drug metabolism and dietary preference, 29 poor metabolizers of dextromethorphan, 18 poor metabolizers of mephenytoin and 134 extensive metabolizers of both drugs were screened for their preferences for various food items. Poor metabolizers of dextromethorphan showed a diminished stated preference for cauliflower and coconut, and poor metabolizers of mephenytoin showed a diminished stated preference for spinach and cabbage.

Adult↗
PubMed1990

The association between Type A behavior and change in coronary risk factors among young adults.

The association of Type A/B behavior pattern and changes in blood pressure, total serum cholesterol, serum triglyceride, body mass, and smoking was estimated in a cohort of 375 young Black and White men and women from a rural county in Central Kentucky between 1978-79 and 1985-88. Type A participants experienced significant increases in systolic (2.90 +/- 1.29 mmHg) and diastolic (3.80 +/- 1.17 mmHg) blood pressure and in cigarette smoking (3.26 +/- 0.89 cigarettes per day) over the eight-year follow-up period, but Type B participants experienced no change. Type A and B individuals showed similar changes in total serum cholesterol, serum triglyceride, or body mass. Differences between behavioral types in blood pressure were present for women but not men, and for Blacks but not for Whites. These findings suggest a possible significance of the Type A pattern for the development of cardiovascular risk of young adults.

Adult↗
PubMed1989

Blood pressure trends associated with changes in height and weight from early adolescence to young adulthood.

In children, blood pressure is more closely related to height and indices of maturation than to age. This study extends observations on the relationship between height, weight, maturation and blood pressure during early adolescence into young adulthood. Standardized measurements of blood pressure, height, and weight were initially obtained in all 14-15 year old adolescents (N = 304) in a rural Kentucky school system. Measurements were repeated 5 and 8 years later. Adolescents with relatively high blood pressures continued to have higher blood pressures as young adults. Increases in systolic and diastolic blood pressure over time were related to increases of relative weight in both sexes (p less than 0.0001 and p less than 0.005, respectively), and in males increases of systolic blood pressure were related to increases of height (p less than 0.005). However, males who attained their full height at younger ages had higher blood pressures both during adolescence and subsequently, as young adults. Thus blood pressure of young adults is related to blood pressure in adolescence, relative weight and change in relative weight since adolescence, and in males to age of maturation as determined by the age at which adult height is attained.

Adolescent↗
PubMed1989

The role of atmospheric pressure variation in the development of spontaneous pneumothoraces.

It has been postulated that spontaneous pneumothoraces (SP) develop because of rupture of subpleural blebs, and that atmospheric pressure changes (delta AP) may be contributory. A 5-year retrospective analysis of SP admissions was carried out to determine if delta AP do play a role in SP development. Using a 36-yr record of hourly delta AP, a normative background for delta AP was constructed. A fall in AP below the fifth, or a rise above the ninety-fifth percentile during these time periods, was classed as "unusual." Atmospheric pressure changes in the 4 days prior to SP were analyzed. The expected frequency of SP occurring by chance, if no relationship to delta AP existed, was also calculated. A total of 192 cases of SP was analyzed. Traumatic pneumothoraces were excluded. The majority of cases (72%) had been exposed to at least one "unusual" delta AP in the 4 days prior to onset of symptoms. Among those with four or more "unusual" exposures, SP occurrence was significantly more frequent than expected by chance alone (p less than 10(-10]. A strong positive association between delta AP and SP was not found in all cases, as delta AP are unlikely to be the only causative factor for SP. This finding of a relationship with ambient pressure changes lends support to the theory that SP develop as a result of rupture of subpleural blebs.

Adult↗
PubMed1986

Impact of a rural high blood pressure control program on hypertension control and cardiovascular disease mortality.

Kentucky is a predominantly rural state with relatively high death rates from hypertension and cardiovascular disease. We report the results of a community-based high blood pressure control educational program undertaken in two rural counties of southeastern Kentucky. In the intervention counties, systolic and diastolic blood pressures of both men and women decreased despite the five-year increase in age; moreover, hypertension was better controlled after the program, and substantial decreases in deaths due to cardiovascular disease were seen. These differences were greater among men in the two regions than among women. The results of this program suggest that, in sparsely populated rural areas, existing resources and programs can be successfully utilized in a communitywide cardiovascular disease risk reduction educational program.

Adolescent↗
PubMed1983

Blood pressure related echocardiographic changes in adolescents and young adults.

In 1973, standardized blood pressure measurements were obtained in 837 high school students in Bourbon County, Kentucky, a rural county with a high prevalence of individuals with systemic hypertension. In 1978, follow-up measurements of blood pressure were performed in selected individuals who were in the high, intermediate, and low ranges of the initial sex-specific blood pressure distributions. Relative rank order of initial blood pressure measurements over the five-year period was maintained. The results of this population-based study provided an opportunity to evaluate the cardiac status in young adults with relatively high blood pressures maintained over five years. Standard m-mode echocardiographic examinations were, therefore, performed over five years. Standard m-mode echocardiographic examinations were, therefore, performed at the time of follow-up. In individuals in the low and intermediate ranges for systolic blood pressure, indices of ventricular hypertrophy were directly correlated with blood pressure level. Among individuals with higher values for systolic blood pressure, after adjusting for the effects of relative body size, indices of ventricular hypertrophy were not significantly different from those noted in the intermediate group. Indices of cardiac performance and estimated left ventricular systolic wall stress were, however, significantly elevated in this "high" blood pressure group. Early in the course of systemic hypertension increased wall stress, rather than hypertrophy, appears to be the primary cardiac manifestation of elevated systolic blood pressure.

Adolescent↗
PubMed1982

Improved prediction of fetal lung maturity in diabetic pregnancies: a comparison of chromatographic methods.

Following planned termination of pregnancy, infants of diabetic mothers have shown a continued vulnerability to the respiratory distress syndrome (RDS), suggesting false positive results on fetal lung maturity testing. We studied the adequacy of the standard one-dimensional chromatographic lecithin/sphingomyelin (L/S) ratio for predicting RDS in 56 diabetic and 50 nondiabetic pregnancies. An exceptionally low incidence of RDS was noted for the study (0.95%) as well as for diabetic pregnancies alone (1.85%). The clinical results were further compared to a new method for determining L/S ratios and identifying other pulmonary phospholipids by two-dimensional chromatography. Values for two-dimensional L/S ratios were significantly lower from 36 through 38 weeks' gestation (P less than 0.01), suggesting improved accuracy and a lessened risk for false positive results in preterm deliveries. Positive identification of amniotic fluid phosphatidylglycerol (PG) was related to increasing L/S ratios (P = 0.001), but only 50% of nondiabetic and 16.7% of diabetic amniotic fluid samples contained PG when the L/S was 2:1 or greater (P = 0.02). The identification of PG serves to confirm fetal lung maturity, but the L/S ratio remains the best available indicator of fetal lung maturity for all high-risk pregnancies.

Chromatography↗
PubMed1982

Blood pressure of young mothers and their children after hypertension in adolescent pregnancy: six- to nine-year follow-up.

To determine if gestational hypertension during adolescent pregnancy is associated with subsequently elevated blood pressure, blood pressures were measured in young mothers 3-6 years and again at 6-9 years after their first pregnancy. Follow-up study groups were selected from an original study population of 409 pregnant adolescent women followed at the university of Kentucky Medical Center between 1971 and 1974 in a specially designated Young Mothers' Program. Blood pressures measured during the first and second follow-up surveys were highly correlated. Compared to matched control subjects who remained normotensive throughout pregnancy (n = 54), women with a history of hypertension during pregnancy (n = 70) were heavier, maintained higher blood pressure, and had a greater incidence of hypertension in subsequent pregnancies. At the second follow-up survey, systolic blood pressure and body weight of male children born to women who experienced gestational hypertension were greater than respective values in males born to women with normotensive pregnancies. Blood pressures of female children of the two groups of young mothers did not differ. Overall, blood pressures and body weights of young mothers correlated with blood pressures and body weights of both their children and their own mothers. The results suggest that gestational hypertension may unmask a tendency for hypertension.

Adolescent↗
PubMed1982

Low renin-aldosterone in "prehypertensive" young adults.

PRA is suppressed in approximately 25% of patients with essential hypertension. To determine if renin suppression precedes the onset of hypertension, PRA and plasma aldosterone were measured before and after treadmill exercise in 129 young adults with relatively high, intermediate, or relatively low blood pressures sustained over 5 yr. PRA and aldosterone responses to exercise were lower (P less than 0.01) in the high blood pressure group. In contrast, plasma renin substrate was lower (P less than 0.01) in the low blood pressure group. Unrelated to blood pressure, PRA, but not aldosterone, was lower in black than in white subjects both before and after exercise. In conclusion, renin suppression precedes the onset of hypertension and may be an appropriate response to higher levels of arterial pressure.

Adolescent↗
PubMed1981

Influence of potassium cardioplegia versus ischemic arrest on regional left ventricular diastolic compliance in humans.

To compare the effects of hypothermic ischemic arrest versus hypothermic potassium cardioplegia, regional left ventricular performance was monitored in 20 adult male patients undergoing saphenous vein bypass operation. Twelve patients received ischemic arrest (Group 1), and 8 received potassium cardioplegia (Group 2). Groups 1 and 2 did not differ in left ventricular ejection fraction (0.62 versus 0.60), number of bypassed vessels (3.7 versus 3.4), mean cross-clamp time (75 versus 63 minutes), or mean cardiopulmonary bypass time (182 versus 170 minutes). Before cardiopulmonary bypass was begun, a pair of ultrasonic crystals was secured in the left ventricular anterior myocardium to measure segment motion and a micromanometer-tipped catheter was placed in the left ventricular chamber. All patients received a saphenous vein bypass graft to a vessel supplying the anterior left ventricular wall in the region of the ultrasonic crystals. Comparison of changes in systolic measurements revealed no significant differences between Groups 1 and 2. After saphenous vein bypass grafting, the left ventricular end-diastolic pressure (11.4 to 17.0 mm HG) and modulus of left ventricular segment stiffness (0.37 to 0.67, p less than 0.02) were elevated in Group 1 but no changes were observed in Group 2 (14.0 to 15.6 mm Hg, and 0.16 to 0.24, respectively). Compared with hypothermic ischemic arrest, hypothermic potassium cardioplegia is not associated with an increased left ventricular diastolic stiffness shortly after saphenous vein bypass grafting in humans.

Angina Pectoris↗
PubMed1981

Nicotine exposure and Parkinson disease.

The observed inverse relationship between smoking and Parkinson disease has prompted suggestions that nicotine, a centrally active agent, might protect against the disease. In this case-control study, cases were found to have ever regularly smoked cigarettes significantly less frequently than sex-, race-, and age-matched neighbors. This report analyzes the detailed smoking histories of cases and neighbors to see if these histories support the nicotine protection hypothesis. Estimated nicotine exposure before age at onset of symptoms for smoking cases was 186.1 g; for smoking controls it was 208.3 g (p = 0.34). Among the cases, severity of disease was not related to the extent of nicotine exposure before disease onset. Age at onset of symptoms for smoking cases (52.7 years) was not delayed (57.8 years for nonsmoking cases). Since the study was unable th find further support for the nicotine protection hypothesis, it is concluded that the observed inverse relationship between smoking and Parkinson disease is likely explainable by other factors, such as selective mortality or pre-morbid behavioral and/or constitutional changes.

Adult↗
PubMed1980

Cigarette smoking and Parkinson disease: 1. Comparison of cases with matched neighbors.

In previous studies, there were fewer cigarette smokers among persons with Parkinson disease than among other patients. We reinvestigated this phenomenon, using nonpatient controls. In home interviews with 237 Parkinson patients and 474 age-, sex-, and race-matched neighbors, we inquired about consumption of tobacco, coffee, tea, and alcohol. All Parkinson patients were diagnosed by a neurologist, had two or more cardinal features of parkinsonism, and had not received chronic phenothiazine therapy. One hundred fifty (63%) of 237 cases and 224 (47%) of 474 controls never smoked cigarettes (p < 0.0001). Significantly different smoking rates were also preset at 10 and 20 years before the onset of parkinsonism.

Adult↗
PubMed1980

Maternal perception of fetal movement and perinatal outcome.

The maternal perception of fetal activity was studied in 306 clinic patients who counted for 2 predetermined hours each day. "Alarming" and "reassuring" fetal movement patterns were defined from statistical analysis. All reassuring fetal movement patterns were followed by reactive nonstress tests (NSTs), and the 2 nonreactive NSTs were preceded by alarming fetal activity. No relationship between urinary estriol determinations and prior fetal activity was present. Excluding congenital anomalies, perinatal distress was infrequent with prior reassuring fetal activity and arose primarily from intrapartum factors. An alarming fetal movement pattern was twice as frequent in high-risk pregnancies and was associated with a significantly greater risk of subsequent perinatal distress (P less than .0001). Clinical applications of the proposed technique are discussed.

Adult↗
PubMed1977

Double-blind study to investigate methods to prevent cephalothin-induced phlebitis.

Methods which might be useful in preventing cephalothin-induced phlebitis following intravenous administration of the buffered drug were investigated. One hundred and twenty adult orthopedic patients were assigned randomly to either a control group or one of five treatment groups. The treatment regimens studied were: addition of hydrocortisone phosphate 10 mg to each liter of intravenous fluid; addition of heparin 1,000 units to each liter of intravenous fluid; addition of heparin 500 units and hydrocortisone phosphate 1 mg to each liter of intravenous fluid; addition of heparin 1,000 units and hydrocortisone phosphate 10 mg to each liter of intravenous fluid; and filtration of intravenous solutions through a 0.22-mum inline filter. All patients in the study received intravenous buffered cephalothin at a dosage of 1 g every six hours for a minimum of 48 hours. Phlebitis was assessed every 12 hours according to predetermined criteria. Significant differences were found in the incidence of phlebitis at 48 hours between the control group and the last three study groups (see above). It is concluded that postinfusion phlebitis following cephalothin administration can be reduced by the concomitant addition of heparin and hydrocortisone to the intravenous solution or by the use of an inline 0.22-mum final filter.

Adolescent↗
PubMed1976

Bias of the cover test in the diagnosis of alternating tropia.

In the evaluation of patients with alternating tropia, all errors tends to falsely overclassify the fixation pattern as free alternation and underestimate monocular fixation. This bias is particularly undesirable in infants when the cover test is used because more direct measurements of visual acuity are not possible.

Fixation, Ocular↗
PubMed1975

Filtration and infusion phlebitis: a double-blind prospective clinical study.

The effect of final filtration on the incidence of infusion phlebitis was studied in a prospective, double-blind investigation involving 146 postoperative patients. The incidence of infusion phlebitis was found to be significantly reduced when an inline, 0.45-mum membrane filter was used. The greatest reduction of infusion phlebitis was in the filter groups receiving unbuffered solutions and no set change over the 72 hours of therapy. Buffering the infusion fluid or 24-hour change of the administration set did not have any effect on reducing the incidence of phlebitis. Antibiotic therapy appeared to have a slightly beneficial effect only when inline filters were employed. A significant rise in white blood cell count and an increase in sedimentation rate were observed in the patients receiving unfiltered fluids. It is recommended that inline final filters should be a part of routine intravenous therapy.

Adolescent↗