PubMed Health⌕ Search

Biomedical subjects

G Sexton

Publications and source records attributed to G Sexton.

50 records · Page 3Linked to original sources
PubMed1991

Chronic blood hyperviscosity in subjects with acute stroke, transient ischemic attack, and risk factors for stroke.

The origin and significance of blood hyperviscosity in subjects with acute stroke has been controversial. It has been argued that viscous abnormalities simply reflect either elevated hematocrit or an acute-phase response to the stroke itself. To address these issues, we measured the factors that determine blood viscosity in a cross-sectional study of 430 subjects, including 135 with acute stroke, 89 with acute transient ischemic attacks of the brain, 115 with recognized risk factors for stroke, and 91 healthy controls. The at-risk group was balanced with the acute stroke group for types of risk factors and medication usage, and all four groups were balanced for age. The viscosity of whole blood at low rates of shear and the plasma viscosity were significantly elevated in both groups with cerebrovascular symptoms and in the at-risk group compared with the healthy controls. The severity of hyperviscosity was stroke group greater than transient ischemic attack group greater than at-risk group greater than healthy controls. Increased viscosity of whole blood was associated with an elevated plasma fibrinogen concentration and with a decreased albumin/globulin ratio. This study provides evidence that blood hyperviscosity is present not only in subjects with acute brain infarction, but also in those with risk factors for stroke, and that these abnormalities are, to a considerable degree, chronic.

Acute Disease↗
PubMed1990

The rate of bone mineral loss in normal men and the effects of calcium and cholecalciferol supplementation.

OBJECTIVE: To determine the rate of bone loss in normal men, and to examine the effects of dietary calcium and cholecalciferol supplementation on bone loss in men. DESIGN: Double-blinded, placebo-controlled 3-year trial of supplementation with calcium (1000 mg/d) and cholecalciferol (25 micrograms/d). SETTING: Clinical research center at a university medical facility. SUBJECTS: Normal men 30 to 87 years old, recruited from the Portland community. MEASUREMENTS AND MAIN RESULTS: Radial bone mineral content (assessed by single-photon absorptiometry) fell by 1.0%/y (95% CI, -1.3% to 0.7%) at a proximal radial site and 1.0%/y (95% CI, -1.4% to -0.6%) at a distal radial site. Vertebral bone mineral content (assessed by dual-energy quantitative computed tomography) declined by 2.3%/y (95% CI, -2.8% to -1.8%). In these healthy men with a high basal dietary calcium intake (1159 mg/d), calcium and cholecalciferol supplementation did not affect bone loss at any site. CONCLUSIONS: Normal men experience a substantial bone loss at both axial and appendicular sites that is not prevented by calcium and vitamin D supplementation in a well-nourished population.

Adult↗
PubMed1990

Elevated plasma homocyst(e)ine concentration as a possible independent risk factor for stroke.

Homocyst(e)ine refers to the sulfur-containing amino acids homocysteine, homocystine, and homocysteine-cysteine mixed disulfide, which normally exist in plasma in both the free and protein-bound forms. Marked hyperhomocyst(e)inemia is associated with well-recognized complications of occlusive thrombotic events and a characteristic syndrome. It is less clear whether mild to moderate elevations in plasma homocyst(e)ine concentrations (i.e., 1.5-5-fold increases) also represent a risk factor for stroke and, if so, whether it is independent of other recognized risk factors. To examine these questions we compared the plasma homocyst(e)ine levels in 41 patients with acute strokes, 27 patients with transient ischemic attacks, 31 patients with recognized risk factors for but no recent symptoms of cerebrovascular disease, and 31 normal volunteers (controls). Plasma homocyst(e)ine concentration was moderately but significantly higher in the patients than in the controls (p less than 0.0001). Approximately 30% of the patients had homocyst(e)ine levels higher than the controls. No relation was found between homocyst(e)ine concentration and other recognized stroke risk factors or stroke type; however, a positive correlation was found between serum uric acid and plasma homocyst(e)ine levels. These data suggest that a moderately elevated plasma homocyst(e)ine concentration may be an independent risk factor for cerebrovascular disease.

Cerebrovascular Disorders↗
PubMed1989

The hypolipidemic effects of gemfibrozil in type V hyperlipidemia. A double-blind, crossover study.

Thirteen patients with phenotypic type V hyperlipidemia were treated with either gemfibrozil (Lopid) or a placebo in a randomized, double-blind, crossover study for two 8-week periods. A 4-week baseline period of a low-fat diet preceded the study and served as a dietary control period. A 4-week washout period followed the two 8-week periods. Compared with the placebo phase, gemfibrozil produced a significant reduction in the concentrations of total plasma triglycerides (21.03 vs 5.50 mmol/L) and very low-density lipoprotein triglycerides (14.40 vs 4.59 mmol/L) as well as in total plasma cholesterol levels (10.88 vs 5.62 mmol/L) and very low-density lipoprotein cholesterol (6.66 vs 2.15 mmol/L). Chylomicronemia was virtually abolished by the drug treatment. As expected in treated patients with type V hyperlipidemia, concentrations of low-density lipoprotein cholesterol rose after therapy with gemfibrozil (3.08 mmol/L) as compared with placebo (1.84 mmol/L); high-density lipoprotein cholesterol also increased (0.85 mmol/L after therapy with gemfibrozil, 0.62 mmol/L after placebo). The previously very low values for both of these lipoproteins increased at the same time that the total plasma cholesterol value decreased. We conclude that gemfibrozil is a well-tolerated and effective hypolipidemic agent for the treatment of patients with severe hypertriglyceridemia when used in conjunction with a low-fat diet.

Adult↗
PubMed1989

Prevalence of hyperhomocyst(e)inemia in patients with peripheral arterial occlusive disease.

A micromethod adapted for automated determinations was used to measure basal plasma levels of homocyst(e)ine [H(e)]. These levels included the sum of free and bound forms of homocysteine, its disulfide oxidation product, homocystine, and the homocysteine-cysteine-mixed disulfide. Two groups of subjects were studied: apparently healthy individuals (n = 103) and patients with peripheral arterial occlusive disease (PAOD) (n = 47). Because age in PAOD patients was higher than in control subjects, the control subjects were subdivided into younger and older groups (aged 60 years or less and more than 60 years, respectively). The H(e) levels in the younger groups were 11.18 +/- 3.58 (mean +/- SD, expressed as homocysteine) and 8.58 +/- 2.82 nmol/ml in men and women, respectively; in the older groups, the levels were 10.74 +/- 2.16 and 9.04 +/- 2.16 nmol/ml in men and women, respectively. There was a positive correlation of H(e) levels with age in the younger control women (r = 0.373; p less than 0.02); no significant correlations were present in the other three control groups. Levels of H(e) in PAOD patients (15.44 +/- 5.76 and 17.04 +/- 8.26 nmol/ml in men and women, respectively) were significantly higher than those indicated above in the older controls. Next, the PAOD patients were assigned to two subgroups: 1) those with normal levels of H(e) (within two standard deviations of the mean of the control values) and 2) those with elevated levels of H(e). Age, cholesterolemia, and the prevalence of smoking and diabetes were similar in both subgroups. These results suggest that elevated plasma H(e) is an independent risk factor for arterial occlusive disease.

Age Factors↗
PubMed1984

Knowledge of and attitudes toward coronary heart disease and nutrition in Oregon families.

In an effort to examine knowledge about heart disease and nutrition and attitudes toward dietary change, 754 women and 125 men were interviewed. The majority of respondents recognized the association between coronary heart disease and various risk factors, including dietary cholesterol. Although they acknowledged the value of dietary change in reducing risk, the majority denied that the food they now eat increases their risk for heart disease, which suggests a lack of perception about possible benefits to be derived from dietary change. The importance of addressing perceived barriers to change is discussed.

Adult↗
PubMed1984

The family heart dietary intervention program: community response and characteristics of joining and nonjoining families.

A random sample of 501 eligible families was selected from a designated neighborhood in Portland, Oregon, and given the opportunity to join a 5-year intervention program promoting a low-fat and low-cholesterol eating pattern designed to reduce risk for coronary heart disease. Participation entailed three baseline assessments of clinical, dietary, and psychological indices, periodic follow-up measurements, and monthly small group meetings led by psychologists and nutritionists. A prior home health survey allowed comparisons of respondents from joining and nonjoining families in terms of reported health status, health beliefs, health locus of control, knowledge about health and nutrition, and demographic characteristics. Almost half (47%) of all invited families agreed to join this long-term nutrition intervention program and completed the necessary baseline assessments. Factors discriminating joiners and nonjoiners were not generally consistent with the health belief model of preventive health behavior. Joiners were similar to nonjoiners in terms of perceived susceptibility to disease, family health histories, and reports of elevated plasma cholesterol levels in the family. However, families with hypertensive members were less likely to join this heart disease prevention program. Positive predictors of participation included higher occupational status, greater knowledge about heart disease, a more internal health locus of control, and the belief that there are few barriers preventing the adoption of a healthier low-fat eating pattern. These findings indicate that there is widespread community interest in optimal nutrition, and they also provide suggestions as to what motivates the general public to take preventive health actions.

Adolescent↗
PubMed1984

The effects of familial relationships, age, body weight, and diet on blood pressure and the 24 hour urinary excretion of sodium, potassium, and creatinine in men, women, and children of randomly selected families.

Two hundred thirty-three randomly selected families provided a population for studying the effects of familial relationships, age, diet, body weight, and urinary electrolyte excretion on blood pressure. There was a strong familial component for urinary sodium, potassium, and creatinine excretion and for systolic blood pressure. In individuals, age, heart rate, and body weight were independently related to blood pressure. In women, urinary sodium and potassium levels were related to diastolic blood pressure. These individual relationships persisted when age was accounted for but were no longer significant after adjusting for both age and body weight, suggesting that heavier people eat more food, which in our culture means greater sodium intake. In fact, our randomly selected families were eating as much sodium (130 to 170 meq/day) and as little potassium (50 to 70 meq/day) as consumed by Americans several decades ago. Furthermore, this study again documented the rise in blood pressure with age, which may represent the effect of environmental influences on blood pressure over time. The familial aggregation of urinary sodium, potassium, and creatinine excretion, along with the well-established familial aggregation of body weight, emphasizes the importance of the entire family in the treatment and prevention of hypertension.

Adolescent↗
PubMed1982

The effects of age, body wight and family relationships on plasma lipoproteins and lipids in men, women and children of randomly selected families.

Two hundred thirty-three families were randomly selected from a designated population base. Data from 619 persons ages 6--65 years had distributions of lipid and anthropometric values typical for the U.S. population. The typical rise in plasma cholesterol and triglyceride with age was also demonstrated. The plasma cholesterol and low-density lipoprotein (LDL) correlated more strongly with age than body weight, whereas the plasma triglyceride was more related to body weight than to age. High-density lipoprotein (HDL) was inversely correlated with weight and plasma triglyceride. Family membership accounted for approximately 20% of the variability in cholesterol, LDL, HDL and weight. Related family members (father-child, mother-child and siblings) had strong correlations for plasma cholesterol, LDL and HDL. These measurements did not correlate in the spouse pairs. The plasma triglyceride did not correlate for the family as a whole nor for the individual family members. This study indicates the importance of both chronic environmental factors and genetic family relationships on plasma lipids and lipoproteins.

Adolescent↗
PubMed1981

Criteria for cessation of CPR in the emergency department.

Specific criteria have been proposed for the cessation of cardiopulmonary resuscitation (CPR) in the emergency department. Using these criteria and others, we developed a survey which was completed by 78 physicians practicing emergency medicine. The physicians surveyed did not make decisions to cease CPR that were consistent with any such criteria which might guide them in clinical decision making. In this survey, the type of residency training, the size of city in which the physician practiced, and the number of years an individual had practiced emergency medicine significantly correlated with how he made the decision to cease CPR. Based on a review of the current literature, and due to the fact that considerable and variable ethical and psychological factors weigh in each clinical circumstance, the authors recommend that no criteria be followed for ceasing CPR.

Adult↗
PubMedDate not supplied

Methylphenidate increases the motor effects of L-Dopa in Parkinson's disease: a pilot study.

We determined whether methylphenidate, a dopamine transporter blocker, modifies motor, cognitive, or affective responses to L-Dopa in Parkinson's disease (PD). Five patients who reported benefit from L-Dopa/carbidopa and motor fluctuations were admitted and withdrawn from their usual antiparkinsonian medications. On 3 consecutive days in a randomized double-blinded fashion, they took 0.2 mg/kg oral methylphenidate or placebo followed 30 minutes later by a 1-hour intravenous L-Dopa (2 mg/kg per h) or placebo infusion. Vital signs, tapping, walking, dyskinesias, mood, anxiety, concentration, and arousal were monitored every 30 minutes. Cognitive testing was performed before and following the infusion. Methylphenidate combined with L-Dopa led to greater peak right-hand tapping speed than either alone. Dyskinesia severity increased most when methylphenidate and L-Dopa were co-administered. There were no differences between conditions on the Stroop test, digit ordering, simple reaction time, or covert orienting of attention validity effect. Methylphenidate alone led to improvement in choice reaction time. Change in self-assessed analogue ratings of mood, anxiety, arousal, or concentration did not differ between conditions. Methylphenidate increased the motor effects of L-Dopa with minimal effects on cognitive or affective functions, suggesting a physiologic role for the dopamine transporter in patients with PD with motor fluctuations.

Aged↗
PubMedDate not supplied

Type A behavior and physiologic coronary risk factors in children of the family heart study: results from a 1-year follow-up.

Although Type A behavior is recognized as an independent risk factor for coronary heart disease, little is known about its antecedents. The present study investigated relationships of Type A behavior as assessed by the Hunter-Wolf rating scale to physiologic coronary risk factors in children ranging from 8 to 15 years of age. In addition, gender differences and the stability of Type A behavior and physiologic risk factors were examined. Consistent with data based on adult samples, Type A behavior was generally unrelated to physiologic coronary risk factors and appears to be as stable as the other risk factors. There were no gender differences in either Type A behavior or other coronary risk factors.

Adolescent↗
PubMedDate not supplied

The role of type A behavior and hostility in an elevation of plasma lipids in adult women and men.

Hostility, Type A behavior, and plasma lipids were assessed in a community sample of 352 women and men. After the contribution of age and body mass index to the variation in plasma lipid and lipoproteins were controlled for, persons scoring high on Type A behavior as well as hostility had elevated levels of plasma and low-density lipoprotein (LDL) cholesterol. These findings were replicated in a 1-year follow-up, suggesting that psychosocial factors may have an effect on plasma lipids in typical adults living in the United States.

Adolescent↗