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Biomedical subjects

W H Pan

Publications and source records attributed to W H Pan.

At least 73 records · Page 4Linked to original sources
PubMed1993

Power spectral analysis of the electroencephalographic and hemodynamic correlates of propofol anesthesia in the rat: intravenous infusion.

Based on the tail-flick response to noxious thermal stimuli, we determined in the present study that effective antinociception could be achieved in adult male Sprague-Dawley rats 15 min after intravenous infusion of propofol at 60 mg/kg/h. Simultaneous power spectral analysis of the electroencephalographic (EEG) and systemic arterial pressure signals further revealed a concomitant depression of the activity of all EEG frequency bands (delta, theta, alpha, beta), alongside hypotension, negative inotropic and chronotropic actions, and attenuated baroreceptor reflex and vasomotor activity. These effects were congruent with a plasma concentration of propofol in the arterial blood of 1.70 +/- 0.13 micrograms/ml, as determined by high-performance liquid chromatography.

Anesthesia↗
PubMed1993

Power spectral analysis of the electroencephalographic and hemodynamic correlates of propofol anesthesia in the rat: intravenous bolus administration.

Based on the tail-flick response to noxious thermal stimuli, we determined in the present study that the minimal effective antinociceptive dose of propofol in adult, male Sprague-Dawley rats, given in an intravenous bolus manner, was 10 mg/kg. Simultaneous power spectral analysis of the electroencephalographic (EEG) and systemic arterial pressure signals further revealed a concomitant transient suppression of the EEG activity, primarily in the theta and sigma bands, alongside minor hypotensive and negative inotropic and chronotropic actions, but with maintained vasomotor tone. These alterations followed a time course that paralleled the plasma concentration of propofol in the arterial blood, as detected by high-performance liquid chromatography.

Anesthesia, Intravenous↗
PubMed1993

Vitamin A, Vitamin E or beta-carotene status and hepatitis B-related hepatocellular carcinoma.

A case-control study was carried out in 59 patients with newly diagnosed hepatocellular carcinoma and 101 control subjects, who were all male hepatitis B carriers. The odds ratios of hepatocellular carcinoma occurring among hepatitis B carriers in the lowest quartile and those highest quartile of dietary and serum status were 5.3 (1.9 to 15.0) and 86.9 (20.0 to 377.2), respectively. The odds ratios for hepatitis B carriers in the lowest quartile and those in the highest quartile of dietary and serum beta-carotene status were 1.7 (0.7 to 4.1) and 5.0 (1.9 to 13.2). Vitamin E status did not differ in case patients and control subjects. Low education level, heavy consumption of alcohol, and smoking status were also associated with increased odds of hepatocellular carcinoma. Serum retinol, positively associated with dietary retinol, demonstrated an independent effect on hepatocellular carcinoma. This effect may reflect changes in the physiologic condition of the patients at the time of entering the hospital.

Adult↗
PubMed1993

Hemostatic factors and blood lipids in young Buddhist vegetarians and omnivores.

A comparison was made between the hemostatic and lipid profiles of 55 young Chinese Buddhist vegetarians (23 men, 32 women) and 59 Chinese medical students (20 men, 39 women) aged 20-30 y. The modern Buddhist vegetarian diet is high in carbohydrate (63% of energy in men, 58% in women) and has a high polyunsaturated-saturated fatty acid ratio, with moderate fat content (25% for men, 30% for women). Rice and soybean proteins are the major protein sources. This study demonstrated that the major beneficial effects of a modern Buddhist vegetarian diet are on blood concentrations of cholesterol, the ratio of apolipoprotein A-I to apolipoprotein B, glucose, and uric acid, but not on most hemostatic factors studied, which included fibrinogen, factor VIIc, factor VIIIc, and plasminogen. Vegetarian men had significantly higher concentrations of antithrombin III than nonvegetarian men.

Adult↗
PubMed1993

No significant effect of calcium and vitamin D supplementation on blood pressure and calcium metabolism in elderly Chinese.

To examine the effects of calcium and vitamin D supplementation on blood pressure and calcium metabolism, we conducted a randomized, double-blind, 2 x 2 factorial intervention study in 58 institutionalized elderly persons. The subjects were randomly allocated into four groups to receive: (1) calcium (800 mg/day) + vitamin D3 placebo, (2) vitamin D3 (5 micrograms/day) + calcium placebo, (3) calcium + vitamin D3, or (4) placebo treatment. Blood pressure was measured and a 24-h urine specimen and an 8-h fasting blood sample were collected at the time of recruitment before treatment and after 2 and 11 weeks of treatment. The changes in urinary calcium levels and plasma vitamin D concentrations were highly correlated with the corresponding treatments in each group, indicating good compliance. Mean systolic blood pressure decreased slightly during intervention in the group given calcium supplements, but increased slightly in the group given calcium + vitamin D. The data suggest that oral supplements of 800 mg calcium or 5 micrograms vitamin D daily produce no significant effect on blood pressure in the elderly in 11 weeks.

Aged↗
PubMed1992

Foods predictive of nutrient intake in Chinese diet in Taiwan: I. Total calories, protein, fat and fatty acids.

Dietary consumption data obtained by food weighing for 539 households in Taiwan in 1980-1981 were used to search for foods predictive of nutrient intake. The average per capita nutrient intake in each household was calculated for total calories, protein, fat and fatty acids (saturated fatty acids, oleic acid and unsaturated fatty acids). Stepwise multiple regression analysis was carried out to reveal the relative importance of each of 405 food items in the dietary survey data for predicting nutrient intake. We found that as few as seven to 20 food items could account for a large proportion of the variability of macronutrient intake in this population. These lists of foods were the minimum needed to categorize an individual's nutrient intake for epidemiological studies in Taiwan. The types and amounts of cooking oils (important predictors of fat and calories) added to the dishes were found to vary from family to family, and should be considered in designing dietary questionnaires for Chinese in other societies.

Adolescent↗
PubMed1992

Foods predictive of nutrient intake in Chinese diet in Taiwan: II. Vitamin A, vitamin B1, vitamin B2, vitamin C and calcium.

Dietary consumption data obtained by food weighing for 539 households in Taiwan in 1980-1981 were used to search for predictor foods of individual intake of several vitamins and calcium. Stepwise multiple regression analysis was carried out on food items that were univariately and significantly associated with nutrient intakes, to screen for the important predictors. Less than ten foods were enough to explain more than 90% of the interperson variation for vitamin A, vitamin B1, and vitamin B2. For vitamin C and calcium, 20 food items could explain only 87% of the variation. Salt, brown sugar, and soy bean sauce were selected among calcium predictors. The information on foods predictive of nutrient intake is useful in designing food frequency questionnaires and materials for nutrition education. Although this paper provides such information for Chinese living in Taiwan, some issues described (such as the need to assess spices) may have been overlooked and could be generalized to populations using stir-frying as a major cooking method.

Ascorbic Acid↗
PubMed1992

Correlates of blood pressure differ in high and in low plasma renin groups.

It has been proposed that the aetiology, pathophysiological status, and effective treatment of hypertensives depends on concomitant plasma renin levels. Epidemiological data are scarce on the interrelations of plasma renin activity (PRA), BP and correlates of BP in the general population. Therefore, profiles of BP correlates were compared between low PRA groups and high PRA groups in a relatively healthy population of 321 Chinese government employees working in the Taipei area, in the summer of 1987. The characteristics of the two PRA groups were similar in body mass index, urinary sodium, chloride, calcium excretion and fasting parathyroid hormone. However, the high PRA group was younger, smoked more, and had a higher mean urinary potassium excretion. Fasting plasma glucose, uric acid, and creatinine levels were lower in the low PRA group. Positive relationships between BP and urinary sodium, chloride, potassium, calcium, plasma cholesterol, triglyceride, and glucose, independent of age and body mass index, were demonstrated in the low PRA group, where a volume expansion state may exist. However, in the high PRA state, uric acid, haemoglobin concentration, insulin and parathyroid hormone level were correlated more closely with BP than in the low PRA state. Further studies are needed to examine whether the differing associations between BP and risk factors in the high and low PRA groups reflect different compensatory mechanisms or aetiological factors.

Blood Pressure↗
PubMed1991

The non-iron-deficiency-related difference in hemoglobin concentration distribution between blacks and whites and between men and women.

The relation of hemoglobin concentration to transferrin saturation had two distinct phases in the data of adult men and women (aged 18-44 years) collected in the first National Health and Nutrition Examination Survey (NHANES I): 1) a stable, linear phase of hemoglobin concentration in the range of normal transferrin saturation, and 2) a dramatic fall in hemoglobin concentration as the degree of transferrin saturation decreased below the linear range. This study confirmed that over the linear range of the hemoglobin concentration-transferrin saturation curve, where subjects were adequately iron-nourished, whites had systematically higher hemoglobin concentration values than blacks (0.61 g/dl); also, males had higher values than females (1.895 g/dl). The effects of race and sex on hemoglobin concentration were additive. The variance of the hemoglobin distribution in blacks was also greater than that in whites. Socioeconomic status and smoking status could not explain the above race and sex differences. The impact on the prevalence estimate of reducing the hemoglobin cut-off by 0.5 g/dl is substantial enough to justify a separate standard for blacks.

Adolescent↗
PubMed1991

[Clinical assessment of laryngeal mask airway in general anesthesia with spontaneous breathing].

The laryngeal mask airway (LMA) is a new form of oropharyngeal airway that provides an alternative to endotracheal intubation and face mask anesthesia in certain cases. Once the patient is adequately anesthetised, it can be inserted blindly without recourse to laryngoscopy. The advantages over standard mask anesthesia are: better airway control, minimal leakage of anesthetic gases, and it frees the anesthetist's hands, as no mandibular support is needed. LMA does not guarantee against the risk of aspiration and it is not recommended for use in patients who may have risk of gastric regurgitation. Our preliminary study revealed that a clear and clinical satisfactory airway was obtained in 98.2% of patients. According to the intraoperative respiratory minute volume and arterial blood gases, the patency of the airway did not deteriorate during the course of the anesthesia. Blood pressure and heart rate were compared on induction in group I and II. Succinylcholine 1 mg/kg, thiopentone 4-6 mg/kg and fentanyl 2 micrograms/kg were used in group I while using the same dosage of succinylcholine and thiopentone without fentanyl for group II. We found no significant differences in vital signs between the two groups.

Anesthesia, General↗
PubMed1991

Blood pressure levels, related factors, and hypertension control status of Japanese and Americans.

Blood pressure levels and related factors in Japanese, US whites and US blacks aged 30 to 74 years were compared, using data from the similarly designed national survey of each country in a similar period, i.e., the National Survey on Circulatory Disorders of Japan, 1980 (10,897 persons from all over Japan) and the second National Health and Nutrition Survey of the US, 1976 to 1980 (NHANES-II) (16,204 persons from all over the USA). Data collection methods were judged to be comparable. Data were stratified by age (30-39, 40-49, 50-59, 60-69, 70-74 yrs) and sex. Age-specific and age-adjusted mean systolic BPs of Japanese were generally higher than those of US whites; mean diastolic pressures were similar in the two populations in both men and women. Mean weight and body mass index (BMI) and their standard deviations were lower for Japanese than Americans. In US blacks, BP was higher than in Japanese or in US whites for diastolic in men, and for both systolic and diastolic in women. Systolic BP levels of black men were between those of Japanese and US whites. At specific levels of BMI, Japanese systolic BPs were markedly higher than those of US whites in all age-sex groups, and diastolic pressures were higher in Japanese than in US whites, slightly so at younger ages and more so at ages 60 and over in both sexes. The proportions of all persons with high BP who were receiving antihypertensive treatment and who were controlled were similar in most age-sex groups of the Japanese and US white populations; they were lower in US black men and higher in US black women. In linear regression analyses of BP on BMI controlled for age, slopes were similar for Japanese and Americans. However, given the lower mean BMI and smaller BMI standard deviation (less overweight), partial correlation coefficients between BMI and BP were smaller for Japanese than Americans. These results indicate that overweight plays a lesser role in Japanese than Americans in producing high prevalence rates of hypertension and that other factors are critically involved (e.g., intake of sodium, potassium, calcium, alcohol).

Adult↗
PubMed1990

Positive relationship between urinary sodium chloride and blood pressure in Chinese health examinees and its association with calcium excretion.

The relationships between salt, urinary calcium and blood pressure were studied in 401 middle-aged Chinese men. Seven overnight urine samples were collected. Three consecutive blood pressure measurements were made on two occasions. The 24-h urinary sodium estimate was positively associated with both mean systolic and diastolic blood pressure (P less than 0.001), controlled for age and body mass index. Urinary chloride was also positively associated with blood pressure (P less than 0.001) at a magnitude similar to that of sodium. Potassium was not related to blood pressure. Urinary calcium was significantly correlated to sodium (r = 0.46) and was positively associated with systolic (P less than 0.001) and diastolic (P less than 0.01) blood pressure. The relationship between calcium and blood pressure was partly explained by salt intake. Similar findings were obtained using electrolyte to creatinine ratios. These results confirm the positive relationship between salt and blood pressure within a Chinese population living in Taipei and indicate a possible, positive relationship between blood pressure and urinary calcium excretion, either dependent or independent of salt intake.

Age Factors↗
PubMed1987

The role of relative weight in the positive association between age and serum cholesterol in men and women.

With advancing age from youth on, there is an increase in mean serum cholesterol level of populations in "western" industrialized countries. Since serum cholesterol is one of the established major risk factors for premature coronary heart disease, it is important to explore the degree to which this age trend is physiologic or due to modern life styles. This study used cross-sectional data for 19,730 white men and 13,872 white women from the Chicago Heart Association Detection Project in Industry to investigate one aspect of this question: does weight explain the association between age and serum cholesterol, in particular whether older age is associated with higher serum cholesterol in the absence of overweight. The relationships among age, relative weight, and serum cholesterol were examined through assessment of mean serum cholesterol levels in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, 55-64) and by relative weight (less than 100, 100-109, 110-119, 120-134, greater than or equal to 135). Age and serum cholesterol were positively associated with each other. In women, it was a simple, linear relationship. In men, the degree of this positive association was less in people over age 35-44 than people in younger ages. These age-cholesterol patterns were present in men and women at desirable weight. However, in men aged 18-54, the positive association between age and prevalence of marked hypercholesterolemia (serum cholesterol greater than or equal to 250) was lower in people at desirable relative weight in comparison to those at higher relative weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Blood pressure response of two types of Goldblatt hypertensive rats to enalapril.

Enalapril (MK-421), a new angiotensin converting enzyme inhibitor, reduces the blood pressure in one-kidney, one-clip hypertensive rats at 30 mg/kg p.o. (n = 12). On the fifth day and during the fifth week after renal artery constriction, systolic blood pressure decreased from 196 +/- 4 and 240 +/- 5 mm Hg pretreatment to 159 +/- 8 and 225 +/- 3 mm Hg, respectively (p less than 0.001 and 0.05, respectively) and was maintained at this level for about 8 h. Serum angiotensin converting enzyme activity was significantly inhibited by enalapril. Similarly, enalapril (30 mg/kg p.o.) in two-kidney, one-clip hypertensive rats (n = 18) on the fifth day and during the fifth week after operation resulted in a decrease in blood pressure from 162 +/- 5 and 217 +/- 5 mm Hg to 117 +/- 6 and 120 +/- 7 mm Hg, respectively, to the preoperative normotensive level (113 +/- 1 mm Hg). These results indicate that the renin-angiotensin system may play an important role in the pathogenesis of two-kidney, one-clip hypertensive rats. However, in the pathogenesis of one-kidney, one-clip hypertensive rats, other mechanisms seem to be involved besides the renin-angiotensin system.

Animals↗
PubMed1986

Relationship of clinical diabetes and asymptomatic hyperglycemia to risk of coronary heart disease mortality in men and women.

This epidemiologic study explored the sex differential in risk of death from coronary heart disease in persons with or without clinically diagnosed diabetes or asymptomatic hyperglycemia. Use was made of 9-year follow-up data from the Chicago Heart Association Detection Project in Industry for 11,220 white men and 8,030 white women aged 35-64 years at entry to the Project (November 1967-January 1973). Both clinically diagnosed diabetes and asymptomatic hyperglycemia were associated with an increased risk of death from coronary heart disease. The extent of this association was greater in women than in men in regard to relative risk. However, absolute excess risk for both diabetics and those with asymptomatic hyperglycemia was larger for men than for women. Clinical diabetes appeared to be an independent risk factor for coronary heart disease in both men and women based on multivariate Cox regression analyses. On the other hand, for men, no significant independent effect of asymptomatic hyperglycemia was apparent. Women with asymptomatic hyperglycemia had significantly higher coronary heart disease death rates than normoglycemic women, with adjustment for major coronary heart disease risk factors; in multivariate analyses, the relationship of asymptomatic hyperglycemia to risk of coronary heart disease was of borderline significance (p = 0.054). This study indicates the independent associations of diabetes and possibly asymptomatic hyperglycemia with coronary heart disease mortality, with greater relative significance in women than in men.

Adult↗
PubMed1986

The role of weight in the positive association between age and blood pressure.

This study used cross-sectional data for 19,704 white men and 13,895 white women from the Chicago Heart Association Detection Project in Industry (November 1967 to January 1973) to investigate whether weight explains the association between age and blood pressure, and in particular, whether age is associated with blood pressure and hypertension in the absence of overweight. The relations among age, relative weight, and blood pressure were examined through assessment of mean blood pressure levels and prevalence of hypertension in 25 subgroups stratified by age (18-24, 25-34, 35-44, 45-54, and 55-64 years) and by relative weight (less than 100%, 100-109%, 110-119%, 120-134%, and greater than or equal to 135%). For all five relative weight groups, for both men and women, mean diastolic blood pressure was higher at successive ages. This phenomenon was also seen for systolic blood pressure after ages 35-44 years for men, and after ages 25-34 years for women. On the other hand, the higher the relative weight was, the higher the blood pressure was. Regression analysis demonstrated that the observed relation between age and blood pressure was consistent for all five relative weight groups, including those at desirable weight. These data indicate that for US subjects, age and blood pressure are generally associated in the absence of overweight.

Adolescent↗
PubMed1986

Time trends in the US racial difference in hypertension.

This paper explores time trends in racial differences in hypertension and in mortality from complications from hypertension in the United States. Mortality data were derived from death certificate data compiled by the National Center for Health Statistics and presented in the 1981 Report of the Working Group on Arteriosclerosis. Prevalence data were obtained from five populations--6,672 people screened in 1960-1962 by the National Health Examination Survey (NHES); 20,749 screened in 1971-1975 by the Health and Nutrition Examination Survey (HANES I); 158,539 screened in 1973-1974 by the Hypertension Detection and Followup Program (HDFP); 1 million persons screened in 1973-1975 by the Community Hypertension Evaluation Clinics (CHEC); and 20,325 screened in 1976-1980 by the second Health and Nutrition Examination Survey (HANES II). Mortality data indicate that the nonwhite/white ratios for mortality from complications of hypertension increased between 1940 and 1967 and decreased between 1968 and 1978. Prevalence data show a corresponding recent decrease in black minus white mean blood pressure. Some of the decrease appears to be due to a greater improvement in hypertension control for blacks than for whites. Time trends in the black/white ratio in prevalence of hypertension were examined with differential treatment effects controlled by inclusion as hypertensive those on drug therapy. The results indicate that in addition to differential changes in therapy, the ratio of black/white prevalence of hypertension may also be decreasing. Additional studies are needed to confirm this finding and to explore time changes in racial patterns of risk factors for hypertension.

Black People↗