| For medical practitioners and the general public - High Blood Pressure Journal Article Catalog. |
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| High spontaneous fluctuation in arterial blood pressure improves the assessment of cerebral autoregulation Liu, J., D. M. Simpson, et al. (2005), Physiol Meas 26(5): 725-41. Abstract: Cerebral autoregulation maintains a relatively constant blood flow despite changes of blood pressure in the brain. Linear models have been extensively applied to identify this mechanism, using spontaneous arterial blood pressure (ABP) fluctuation as input and cerebral blood flow velocity (CBFV) change as output. Although valuable measurements have been achieved by these models, accuracy and consistency are of great concern due to the large variability of results. We therefore investigated whether more reliable measurements can be achieved by selecting only those recordings (or parts of recordings) with relatively high spontaneous variability of ABP. Twenty-four recordings, 7 from hypercapnia and 17 from normocapnia, of ABP and CBFV from 9 healthy adults were analyzed. Two conventional autoregulatory parameters were used to assess cerebral autoregulation. In the absence of a 'gold' standard for the study of dynamic cerebral autoregulation, lower variability of the parameters and higher correlation with pCO(2) were considered as criteria for identifying improved measures of autoregulation. Both significantly lower variability of the parameters, and higher correlation between the parameters and pCO(2) were achieved from the data with higher variability of blood pressure. We therefore conclude that ABP with high variability may effectively stimulate regulatory response in blood flow resulting in improved assessment of cerebral autoregulation. |
| High stress responsivity predicts later blood pressure only in combination with positive family history and high life stress Light, K. C., S. S. Girdler, et al. (1999), Hypertension 33(6): 1458-64. Abstract: High cardiovascular responsivity to stressors has not consistently improved prediction of later blood pressure increases beyond the predictive effects of baseline pressure. Animal models suggest that genetic susceptibility to hypertension and frequent stress exposure are important modulating factors in stress-related hypertension. Thus in 103 men originally tested at age 18 to 22 years and reassessed 10 years later, interactive effects of genetic susceptibility (defined as 1 or more hypertensive parents) with high stress responsivity (defined as top 25% on the basis of blood pressure and cardiac responses during both reaction time and cold pressor tasks) were examined in relation to follow-up systolic and diastolic levels and to change in blood pressure status from normal (diastolic<80 mm Hg) to marginally elevated (diastolic 85 to 95 mm Hg). Men with the combination of high stress response and hypertensive parents demonstrated higher systolic (P<0.05) and diastolic levels (P<0.05) at follow-up, and they showed a 7-fold increase (7.5, 95% confidence intervals 2.3, 24.3; P<0.001) in relative risk of change in blood pressure status versus men with no family history and a 3-fold increase (3.8, confidence intervals 1.5, 9.6; P<0.004) versus less stress-responsive men who also had hypertensive parents. In 65 men who also provided ratings of daily stress, family historyxstress responsivityxdaily stress interactions were significant in predicting follow-up systolic and diastolic levels (P<0.006 and 0.03, respectively), with highest pressure levels seen when high life stress was reported by high stress responders and/or men with hypertensive parents. In conclusion, results suggest that stress responsivity as a long-term predictor is modulated by both genetic and environmental factors. |
| High sucrose diets increase blood pressure of both salt-sensitive and salt-resistant rats Preuss, H. G., J. J. Knapka, et al. (1992), Am J Hypertens 5(9): 585-91. Abstract: We examined the effects of a diet relatively high in sugar and low in protein content on systolic blood pressure (SBP) in rats with known pressure responses to salt (NaCl) in order to compare "sugar/protein sensitivity" to "salt sensitivity." Dahl salt-sensitive (DSS) and salt-resistant (DSR) rats were fed one of two low salt diets containing either high sugar (sucrose 51.5% w/w)/low protein (14.6% w/w) or low sugar (sucrose 12.5% w/w)/high protein (52.2% w/w) content. After 3 weeks, the DSS ingesting the high sugar diet/low protein diet developed significantly elevated SBP relative to DSR eating the same high sugar/low protein diet and the DSS and DSR consuming the low sugar/high protein diet. After 2 to 3 months, the SBP of DSR eating the high sugar diet began to rise markedly and eventually both DSS and DSR ingesting the high sugar/low protein diet maintained similarly elevated SBP, significantly higher than DSS and DSR ingesting the low sugar/high protein diet. When Fischer 344 rats, a normotensive, salt-resistant rat strain, were fed the high sucrose/low protein diet, SBP also rose significantly into hypertensive ranges over 2 to 3 months. Since the SBP of DSR and Fischer 344 rats are not influenced to any great extent by high salt intake, even after prolonged exposure, the SBP rise associated with the high sugar/low protein diet may be via a mechanism different from salt-induced hypertension. However, it is also possible that the high sugar/low protein diet creates in DSS and DSR the situation responsible for salt induction in DSS.(ABSTRACT TRUNCATED AT 250 WORDS) |
| High systolic blood pressure in newborn infants and its relation with age, sex, weight, glycemia, hematocrit and method of delivery Menghetti, E. (1980), Panminerva Med 22(4): 229-30. |
| High systolic blood pressure increases cardiovascular risk SoRelle, R. (2004), Circulation 109(13): e9033-4. |
| High systolic blood pressure increases prevalence and severity of retinopathy in NIDDM patients Cignarelli, M., M. L. De Cicco, et al. (1992), Diabetes Care 15(8): 1002-8. Abstract: OBJECTIVE--To determine whether the severity of retinopathy is higher in a group of NIDDM patients with sBP greater than or equal to 140 mmHg compared with NIDDM patients with sBP less than 140 mmHg. RESEARCH DESIGN AND METHODS--Ophthalmoscopy and FAG were conducted among a group of NIDDM patients with either a sBP above (n = 54) or below (n = 55) 140 mmHg. The groups were matched according to diabetes duration, metabolic control (HbA1c), and AER. RESULTS--Patients with sBP greater than 140 mmHg had a higher prevalence of retinopathy, as established according to a rating scale (4.9 +/- 3.8 vs. 3.2 +/- 3.3, P less than 0.02); furthermore, their BMI values were higher (28.1 +/- 4.5 vs. 24.9 +/- 4.1 kg/m2, P less than 0.001). The group of normotensive subjects showed the highest rate of low grading (0-2) values. However, the highest prevalence rates of 8-10 grading values (proliferative retinopathy) were found in the hypertensive group. CONCLUSIONS--These data suggest that sBP values greater than or equal to 140 mmHg favor the onset of retinopathy in NIDDM patients during their 1st 10 yr of disease. |
| High triglycerides and low HDL cholesterol and blood pressure and risk of ischemic heart disease Jeppesen, J., H. O. Hein, et al. (2000), Hypertension 36(2): 226-32. Abstract: Treatment of high blood pressure (BP) has not produced the expected reduction in risk of ischemic heart disease (IHD). Subjects with high BP often have the metabolic syndrome X, an aggregation of abnormalities in glucose and lipid metabolism. We tested the hypothesis that the BP level would be less predictive of risk of IHD in those with high triglycerides (TG) and low HDL cholesterol (HDL-C), the characteristic dyslipidemia in the metabolic syndrome than in those without. Baseline measurements of fasting lipids, systolic BP (SBP), diastolic BP (DBP), and other risk factors were obtained in 2906 men, age 53 to 74 years, free of overt cardiovascular disease. High TG/low HDL-C was defined as TG >1.59 mmol/L and HDL-C <1.18 mmol/L. Within an 8-year period, 229 men developed IHD. In men with high TG/low HDL-C, the incidence of IHD according to SBP (<120, 120 to 140, >140 mm Hg) was 12.5%, 12.9%, and 10.0% (P=NS), respectively, and according to DBP, the incidence of IHD was (<75, 75 to 90, >90 mm Hg) 13.7%, 10.6%, and 13.7% (P=NS), respectively. The corresponding figures for other men were 5.2%, 8. 0%, and 9.7% for SBP (P<0.001), and 6.1%, 7.5%, and 9.9% for DBP (P<0.03). In conclusion, the BP level did not predict the risk of IHD in those with high TG/low HDL-C. This finding may explain the reason lowering BP has not produced the expected reduction in IHD. |
| High-carbohydrate diet: antinatriuretic and blood pressure response in normal men Affarah, H. B., W. D. Hall, et al. (1986), Am J Clin Nutr 44(3): 341-8. Abstract: The hypothesis that high-carbohydrate feeding leads to increased insulin secretion, sodium retention, and elevation in blood pressure was examined in seven healthy men. A baseline 7-day balance study on low (13%) or high (52%) carbohydrate was followed by a 2-wk balance on the alternate diet and a 1-wk balance on the baseline diet. Results indicated that changing carbohydrate intake caused a rapid (2-3 day) inverse change in urinary sodium excretion and balance. By the second week, however, urinary-sodium level returned to baseline accompanied by an inverse change in plasma aldosterone. No significant rise in blood pressure was detected throughout the study. High-carbohydrate feeding promotes sodium retention in normal subjects, but the effect is counterregulated by a reduction in plasma aldosterone. A high-carbohydrate diet in healthy subjects does not cause a significant short-term increase in blood pressure. |
| High-density lipoprotein cholesterol levels increase with age, body mass index, blood pressure and fasting blood glucose in a rural Uygur population in China Yan, W., D. Gu, et al. (2005), J Hypertens 23(11): 1985-1989. Abstract: OBJECTIVES: To investigate the distribution of the serum high-density lipoprotein cholesterol (HDLC) levels and its relationship with obesity, hypertension and diabetes in a Uygur case-control study on hypertension. DESIGN: A case-control (339 hypertensive cases, 272 normotensive controls) study on hypertension was conducted, and obesity, hypertension, lipid profiles and fasting blood glucose were analyzed. METHODS: The demographic data, history of disease and lifestyles, including diet, smoking and salt intake, were recorded and three measurements of blood pressure were obtained by trained observers. The fasting serum lipid profiles and glucose were determined. RESULTS: The HDLC levels of hypertensive participants were significantly higher than normotensive participants after adjustment for age and gender (1.145 versus 1.117 mmol/l, P = 0.001, power = 0.867). After adjustment for related variables, the HDLC levels slightly increased with age, body mass index and fasting glucose (all P = 0.001, power > 0.80) in normotensive participants and only increased with age among hypertensive participants (P = 0.0001, power = 0.971). CONCLUSIONS: The serum HDLC levels in Uygur normotensive participants increased with age, body mass index, blood pressure and fasting glucose levels. This was inconsistent with the previous studies and the reason remained unclear. Further study is needed to elucidate both the environmental and genetic determinants of the novel distribution of the HDLC levels and their association with coronary heart disease in the Uygur population. |
| Higher incidence of high blood pressure in Germans as compared with South European and Turkish guest workers Kornhuber, H. H. and G. Lisson (1982), Med Welt 33(22): 817-9. |
| Higher triglycerides, lower high-density lipoprotein cholesterol, and higher systolic blood pressure in lipoprotein lipase-deficient heterozygotes. A preliminary report Sprecher, D. L., B. V. Harris, et al. (1996), Circulation 94(12): 3239-45. Abstract: BACKGROUND: Heterozygous lipoprotein lipase (LPL) deficiency has been associated with familial hypertriglyceridemia and familial combined hyperlipidemia. Studies of heterozygotes with LPL gene defects at amino acid residues 188 and 207 showed higher triglycerides (TG) and lower HDL cholesterol (HDL-C), with no elevation in LDL cholesterol (LDL-C). Other LPL defects may reveal alternate clinical phenotypes. METHODS AND RESULTS: We evaluated three families with defects at amino acid residues 64, 194, and 188. Thirty-eight heterozygotes (8 with defect 64, 14 with defect 194, and 16 with defect 188) and 95 family members without defects were studied. Plasma lipid, lipoprotein, and apolipoprotein (apo) values were measured, as well as blood pressure. Pooled carriers demonstrated higher systolic blood pressure (SBP) (127 versus 116 mm Hg, P <.0001) and TG (160 versus 125 mg/dL, P =.004) and lower HDL-C (44 versus 52 mg/dL, P =.001) than did noncarriers. A comparison of the 188 carriers and noncarriers revealed the most striking phenotypic characteristics, with lower HDL-C (36 versus 51 mg/dL, P <.0001) and HDL-C/(apo A-I + apo A-II) (0.21 versus 0.24, P =.002) and higher TG (206 versus 123 mg/dL, P =.0003), SBP (132 versus 116 mm Hg, P =.0004), and apo B/LDL-C (1.12 versus 0.93, P <.0001). CONCLUSIONS: These data confirm past observations that LPL deficient heterozygotes trend toward lower HDL-C and higher TG levels while potentially expressing higher SBP. These data also implicate the specific LPL gene defect as a contributing factor to the variable expression of HDL-C, TG, and SBP. |
| High-fat diet elevates blood pressure and cerebrovascular muscle Ca(2+) current Wilde, D. W., K. D. Massey, et al. (2000), Hypertension 35(3): 832-7. Abstract: Dietary fat contributes to the elevation of blood pressure and increases the risk of stroke and coronary artery disease. Previous observations have shown that voltage-gated Ca(2+) current density is significantly increased in hypertension and can be affected by free fatty acids (FAs). We hypothesized that a diet of elevated fat level would lead to an increase in blood pressure, an elevation of L-type Ca(2+) current, and an increase in saturated FA content in vascular smooth muscle cell membranes. Male Osborne-Mendel rats were fed normal rat chow or a high-fat diet (Ob/HT group) for 8 weeks. Blood pressures in the Ob/HT group increased moderately from 122.5+/-0.7 to 134.4+/-0.8 mm Hg (P<0.05, n=26). Voltage-clamp examination of cerebral arterial cells revealed significantly elevated L-type Ca(2+) current density in the Ob/HT group. Voltage-dependent inactivation of the Ob/HT L-type channels was significantly delayed. Total serum FA contents were significantly elevated in the Ob/HT group, and HPLC analyses of fractional pools of FAs from segments of abdominal aorta revealed that arachidonic acid levels were elevated in the phospholipid fraction in Ob/HT. No differences in vascular membrane cholesterol contents were noted. Plasma cholesterol was significantly elevated in portal venous and cardiac blood samples from Ob/HT rats. These findings suggest that an elevation of plasma FAs may contribute to the development of hypertension via a process involving the elevation of Ca(2+) current density and an alteration of channel kinetics in the vascular smooth muscle membrane. |
| High-frequency pressure fluctuations: their significance in the documentation of turbulent blood flow Sabbah, H. N., E. F. Blick, et al. (1977), Cathet Cardiovasc Diagn 3(4): 375-84. |
| Highlights of the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure Carter, B. L. (1998), Am J Health Syst Pharm 55(4): 382-8. |
| High-meat, low-carbohydrate diet in pregnancy: relation to adult blood pressure in the offspring Shiell, A. W., M. Campbell-Brown, et al. (2001), Hypertension 38(6): 1282-8. Abstract: To examine the hypothesis that a high-animal protein, low-carbohydrate diet in pregnancy is associated with raised blood pressure in the adult offspring, we performed a follow-up study of 626 men and women in Motherwell, Scotland, whose mothers' food intake had been recorded during pregnancy. The mothers had taken part in a dietary intervention in which they were advised to eat 1 lb (0.45 kg) of red meat per day and to avoid carbohydrate-rich foods during pregnancy. The offspring were followed up at age 27 to 30 years, and their systolic and diastolic blood pressures were measured. Women who reported greater consumption of meat and fish in the second half of pregnancy had offspring with higher systolic blood pressure in adult life (regression coefficient, 0.19 mm Hg per portion per week; 95% confidence interval, 0.04 to 0.35; P=0.02). High maternal consumption of fish, but not meat, was associated with higher diastolic blood pressure in the offspring (regression coefficient, 1.00 mm Hg per portion per week; 95% confidence interval, 0.18 to 1.82; P=0.02). These associations were independent of maternal blood pressure, body size, and smoking habits during pregnancy. Although we cannot exclude confounding by maternal saturated fat or salt intake, the findings support those of a study in Aberdeen showing higher blood pressure in men and women whose mothers had eaten a high-animal protein, low-carbohydrate diet in late pregnancy. These associations may reflect the metabolic stress imposed on the mother by an unbalanced diet in which high intakes of essential amino acids are not accompanied by the nutrients required to utilize them. |
| High-normal blood pressure and early diabetic nephropathy Chase, H. P., S. K. Garg, et al. (1990), Arch Intern Med 150(3): 639-41. Abstract: The relationship between high-normal blood pressure (BP) levels and early diabetic nephropathy is currently unknown. Blood pressure levels were checked longitudinally for a mean of 6.6 years in 230 subjects to determine their relationship to early diabetic nephropathy as monitored by microalbuminuria. High-normal BP level correlated with the presence of microalbuminuria. Microalbuminuria was 2.8 times as common in subjects with high-normal BP levels compared with those subjects with BP levels below the 90th percentile for their age. The elevated microalbumin excretion was primarily associated with high-normal diastolic BP levels. Our data suggest that either microalbuminuria or high-normal BP levels can precede the other. In a logistics model, diastolic BP and mean HbA1 (over 6.6 years) entered the model at similar levels, followed by duration of diabetes. When the influence of mean HbA1 was removed using logistic regression, the diastolic BP level remained a significant associated factor for the presence of microalbuminuria. |
| High-normal blood pressure and microalbuminuria Knight, E. L., H. M. Kramer, et al. (2003), Am J Kidney Dis 41(3): 588-95. Abstract: BACKGROUND: High-normal blood pressure (BP) is associated with increased cardiovascular risk compared with optimal BP, but no study has specifically examined the association between high-normal BP and microalbuminuria, an established predictor of future cardiovascular events. METHODS: This was a cross-sectional study of normotensive (systolic BP SBP < 140 mm Hg, diastolic BP DBP < 90 mm Hg) individuals without diabetes with no hypertension history enrolled in the Third National Health and Nutrition Examination Survey. BP was categorized as high normal (SBP, 130 to 139 mm Hg or DBP, 85 to 89 mm Hg), normal (SBP, 120 to 129 mm Hg or DBP, 80 to 84 mm Hg), and optimal (SBP < 120 mm Hg and DBP < 80 mm Hg). We also separately examined SBP, DBP, mean arterial pressure (MAP), and pulse pressure. Microalbuminuria was defined using sex-specific cutoff values (urine albumin-creatinine ratio > or = 17 and < or = 250 microg/mg > or =1.0 and < or =28 mg/mmol for men and > or = 25 and < or = 355 microg/mg for women > or =3 and < or =40 mg/mmol). We used multivariate logistic regression to analyze the association between different BP measurements and microalbuminuria. RESULTS: Compared with optimal BP, high-normal BP was significantly associated with increased odds of microalbuminuria (odds ratio OR, 2.13; 95% confidence interval CI, 1.51 to 3.01). Similarly, MAP (OR, 1.41; 95% CI, 1.15 to 1.74 per 10-mm Hg increment), SBP (OR, 1.27; 95% CI, 1.09 to 1.48 per 10-mm Hg increment), and DBP (OR, 1.29; 95% CI, 1.06 to 1.57 per 10-mm Hg increment) were significantly associated with microalbuminuria. CONCLUSION: High-normal BP is significantly associated with microalbuminuria compared with optimal BP and may be a biomarker of the increased cardiovascular risk observed in this population. |
| High-normal blood pressure progression to hypertension in the Framingham Heart Study Leitschuh, M., L. A. Cupples, et al. (1991), Hypertension 17(1): 22-7. Abstract: This study sought to determine if individuals with high-normal blood pressure (diastolic blood pressure of 85-89 mm Hg) progress to hypertension more frequently than those with normal blood pressure (diastolic blood pressure less than 85 mm Hg), thus advancing to a higher cardiovascular risk category. Individuals from the Framingham Heart Study were placed in normal and high-normal blood pressure categories and followed for 26 years for the development of hypertension. With hypertension defined as a diastolic blood pressure of 95 mm Hg or greater or the initiation of antihypertensive therapy, 23.6% of men and 36.2% of women with normal blood pressure developed hypertension compared with 54.2% of men and 60.6% of women with high-normal blood pressure. The relative risk for the development of hypertension associated with high-normal blood pressure was 2.25 for men (95% confidence interval CI, 1.8-2.8; p less than 0.0001) and 1.89 for women (95% CI, 1.5-2.3; p less than 0.0001). The age-adjusted relative risks estimated by the proportional hazards model were 3.36 for men and 3.37 for women (p less than 0.001). Among those risk factors examined, baseline systolic and diastolic blood pressure, Metropolitan relative weight, and change in weight over time were significant predictors of future hypertension in men and women whose initial blood pressure was normal. For men with high-normal blood pressure, systolic blood pressure and change in weight were identified as risk factors for future hypertension. These results indicate that the probability of individuals with blood pressure in the high-normal range developing hypertension is twofold to threefold higher than in those with normal blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS) |
| High-normal blood pressure--more "high" than "normal" Panza, J. A. (2001), N Engl J Med 345(18): 1337-40. |
| High-peak-power microwave pulses: effects on heart rate and blood pressure in unanesthetized rats Jauchem, J. R. and M. R. Frei (1995), Aviat Space Environ Med 66(10): 992-7. Abstract: INTRODUCTION: Exposure sources capable of generating high-peak-power microwave pulses, with relatively short pulse widths, have recently been developed. Studies of the effect of these sources on the cardiovascular systems of animals have not been reported previously. METHODS: We exposed 14 unanesthetized male Sprague-Dawley rats to 10 high-peak-power microwave pulses generated by a transformer-energized megawatt pulsed output (TEMPO) microwave source, at frequencies ranging from 1.2-1.8 GHz. Peak power densities were as high as 51.6 kW/cm2. At 14 d prior to irradiation, the animals were implanted with chronic aortic cannulae. With appropriate shielding of the transducer, blood pressure recordings were obtained during microwave pulsing. RESULTS: In a preliminary series of exposures at 1.7-1.8 GHz (peak power density 3.3-6.5 kW/cm2), an immediate but transient increase in mean arterial blood pressure (significant) and decrease in heart rate (non-significant) were observed. A loud noise was associated with each pulse produced by the TEMPO; this factor was subsequently attenuated. In a second series of exposures at 1.2-1.4 GHz (peak power density 14.6-51.6 kW/cm2), there were no significant changes in mean arterial blood pressure or heart rate during microwave exposure. CONCLUSIONS: The earlier significant increase in blood pressure that occurred during microwave exposure appeared to be related to the sharp noise produced by the TEMPO source. After appropriate sound attenuation, there were no significant effects of exposure to the microwave pulses. |
| High-performance hemodiafiltration and blood pressure stability Takenaka, T., Y. Tsuchiya, et al. (1997), Nephron 75(1): 30-5. Abstract: In the present study, we have estimated plasma nonrefilling rate and assessed its relationship to blood pressure stability during hemodialysis (HD) with normal or high sodium dialysate and during high flux hemodiafiltration (HDF). In standard HD, the greater plasma nonrefilling rate resulted in the larger decrease in blood pressure (alpha = -6.7 +/- 0.2 mm Hg/%, p < 0.01, n = 75). When compared to standard HD, high flux HDF (n = 6) altered neither plasma refilling nor blood pressure stability. Finally, the restrictive usage of high sodium dialysate reduced plasma nonrefilling rate (21 +/- 3 vs. 16 +/- 2%, p < 0.05, n = 10) and the magnitude of decrease in blood pressure (16 +/- 6 vs. 9 +/- 4 mm Hg, p < 0.05) without increase in interdialytic weight gain. Our data indicate relative safety of high performance HDF, and warrant judicious use of high sodium dialysate for the HD patients with hypotensive episodes. |
| High-pressure liquid chromatographic analysis of cimetidine, a histamine H2-receptor antagonist, in blood and urine Randolph, W. C., V. L. Osborne, et al. (1977), J Pharm Sci 66(8): 1148-50. Abstract: A method is described for extraction of cimetidine, a histamine H2-receptor antagonist, from whole blood and urine with subsequent analysis by high-pressure liquid chromatography (HPLC). The drug is extracted from biological fluids with 1-octanol and back-extracted into dilute acid and then into a small volume of ethanol by saturation with potassium carbonate. HPLC analysis is performed on a column of 5-micrometer silica with a mixed mobile phase consisting primarily of acetonitrile. The method measures concentrations of cimetidine as low as 0.05 microgram/ml and is reproducible. Blood levels and urinary excretion data obtained with the analytical procedure are given for a group of human subjects who received 200-mg oral doses of cimetidine. |
| High-pressure liquid chromatographic analysis of diazepam, oxazepam and N-desmethyldiazepam in human blood Kabra, P. M., G. L. Stevens, et al. (1978), J Chromatogr 150(2): 355-60. Abstract: We describe a rapid method for precisely measuring concentrations of diazepam, oxazepam and N-desmethyldiazepam in blood by high-pressure liquid chromatography. The drugs, together with an internal standard, prazepam, are extracted from 2 ml of blood and analyzed isocratically on a reversed-phase column with a mobile phase consisting of acetonitrile-0.01 M sodium acetate buffer (35:65 v/v). The eluted drugs are detected by their absorption at 240 nm. The sensitivity of this method is 30 microgram/l for oxazepam and N-desmethyldiazepam, 40 microgram/l for diazapam, for 2-ml blood samples. Relative recovery of added drugs to blood varies from 91 to 110%. The day-to-day precision (coefficient of variation) established by 10 replicate analyses was 2.8 to 9.6%. |
| High-pressure liquid chromatographic analysis of triflubazam and its metabolites in human and animal blood and urine Huettemann, R. E. and A. P. Shroff (1975), J Pharm Sci 64(8): 1339-42. Abstract: A high-pressure liquid chromatographic method is described for analyzing triflubazam 1-methyl-5-phenyl-7-trifluoromethyl-1H-1,5-benzodiazepine-2,4(3H,5H)-dion e and its primary metabolites in blood and urine. Adsorption chromatography, using pellicular silica gel as the stationary phase and dioxane-isooctane as the mobile phase, permitted rapid sample analysis. After extraction of blood and urine samples with toluene, quantitation is achieved using liquid chromatography with an internal standard. The method is sensitive above 50 ng/ml of triflubazam and its known metabolites. Recoveries for all compounds from blood or urine averaged above 95 percent. The specificity of the method was established by collecting samples separated by liquid chromatography and characterizing them by mass spectrometry. Human and animal data are presented to illustrate the utility of the method. |
| High-pressure liquid chromatographic determination of amitriptyline and its major metabolites in human whole blood Smith, G. A., P. Schulz, et al. (1982), J Pharm Sci 71(5): 581-3. Abstract: A sensitive, specific, high-pressure liquid chromatographic method using an internal standard was developed for the determination of amitriptyline and its major metabolites in whole blood. Analysis was carried out on a microparticulate silica column with a mobile phase consisting of acetonitrile-methanol-aqueous ammonium hydroxide (93:7:0.4). Linear calibration curves ranging to 250 ng/ml were obtained for all compounds using UV absorbance detection at 220 nm. The lower limit of detection was 2 ng/ml for amitriptyline and 10-hydroxyamitriptyline, and 6 and 16 ng/ml for nortriptyline and its 10-hydroxylated metabolite, respectively. Human whole blood samples collected after single intravenous and single oral doses can be analyzed using this procedure. |
| High-pressure liquid chromatographic determination of benfurodil hemisuccinate in blood and urine (author's transl) Turcant, A., M. Patay, et al. (1979), J Chromatogr 164(2): 195-203. Abstract: A sensitive and reliable method for quantitative determination of benfurodil hemisuccinate and benfurodil in plasma by high-pressure liquid chromatography on a Zorbax SIL column with a mean particle size of 7 micrometer and UV detection at 254 nm is described. Benfurodil hemisuccinate is stable in plasma but not in aqueous solutions. This is explained by its great fixation to plasma proteins which has been shown by equilibrium dialysis. |
| High-pressure liquid chromatographic determination of cimetidine sulphoxide in human blood and urine Lee, R. M. and P. M. Osborne (1978), J Chromatogr 146(2): 354-60. |
| High-pressure liquid chromatography/electrochemical detection method for monitoring MDA and MDMA in whole blood and other biological tissues Michel, R. E., A. B. Rege, et al. (1993), J Neurosci Methods 50(1): 61-6. Abstract: The drug Ecstasy (3,4-methylenedioxymethamphetamine (MDMA)) is one of several hallucinogenic amphetamine derivatives reported to be serotonergic neurotoxins. The following is a description of a new high-pressure liquid chromatographic (HPLC) analytical method for the analysis of MDMA, 3,4-methylenedioxyamphetamine (MDA) and N-ethyl-3,4-methylenedioxyamphetamine (MDE) from whole blood. Upon separation of MDMA, MDA and MDE by HPLC, quantitation is achieved by use of electrochemical detection. Retention times for MDA, MDMA, and MDE are 6.5, 9.2, and 10.3 min, respectively, allowing for a complete chromatographic run every 15 min. The sensitivity of the method is 1 ng/ml which allows for measurement of MDA, MDMA, or MDE in microsamples of whole blood. The volume of blood required is very small (200 microliters); therefore, there is minimal blood loss in repeated blood sampling from small animals. Assay linearity was demonstrated from 1 ng/ml to at least 1 microgram/ml. The coefficients of variation for both intra-assay and inter-assay comparisons were less than 9%. Other HPLC methods have been previously described for the analysis of amphetamine derivatives, but this new method offers greater sensitivity, rapid turn-around time and ease of use. |
| High-rate cardiac pacing increases blood pressure and decreases right atrial pressure in patients with hemodynamic significant acute right ventricular myocardial infarction and bradyarrhythmia Vrouchos, G. T., A. Kiulpalis, et al. (1997), Clin Cardiol 20(1): 41-6. Abstract: BACKGROUND: In an 84-year-old patient with acute right ventricular myocardial infarction (RVI), complete heart block, and low cardiac output, a significant increase in blood pressure (BP) and decrease in right atrial pressure (RAP) were accidentally observed during the performance of high-rate ventricular pacing. METHODS: Based on that observation, the acute effects of high-rate cardiac pacing (VVI or AAI) on BP and RAP were studied in 15 consecutive patients (67.4 +/- 7.7 years), with hemodynamically significant RVI. Ten had advanced heart block and five had sinus bradycardia. Cardiac pacing with simultaneous recording of BP and RAP at intrinsic rhythm and at heart rates of 70, 90, 110, 130 beats/min was performed. RESULTS: Systolic BP (SBP) increased significantly from 94.6 +/- 15 mmHg during intrinsic rhythm to 101.9 +/- 13.8 mmHg-127 +/- 12.2 mmHg at heart rates 70-130 beats/min (p < 0.0001). Diastolic BP (DBP) also increased from 48.2 +/- 8.7 to 53.9 +/- 3.7-69.1 +/- 3 mmHg at heart rates 70-130 beats/min, (p < 0.014-0.0001). Mean RAP decreased from 14.5 +/- 5 to 14.1 +/- 5 mmHg-11.1 +/- 4.1 mmHg at heart rates 70-130 beats/min (p = 0.16-0.0001). Significant elevation of SBP (p < 0.007), DBP (p < 0.0075), and decrease of RAP (p < 0.038) were also detected by comparing the usual pacing rate at 70 beats/min with pacing rates at 90-130 beats/min. CONCLUSIONS: These findings, if demonstrated over a prolonged period during the acute state of RVI, may influence the management of patients with RVI to include high-rate cardiac pacing, probably in the range of 80-110 beats/min. |
| High-rate transcranial magnetic stimulation: influence on short-term-memory, heart rate and blood pressure changes Claus, D., A. Foerster, et al. (1999), Electroencephalogr Clin Neurophysiol Suppl 50: 408-12. |
| High-resolution mapping of the blood pressure QTL on chromosome 7 using Dahl rat congenic strains Cicila, G. T., M. R. Garrett, et al. (2001), Genomics 72(1): 51-60. Abstract: It was previously shown using Dahl salt-sensitive (S) and salt-resistant (R) rats that a blood pressure quantitative trait locus (QTL) was present on rat chromosome 7. In the present work, this QTL was localized to a region less than 0.54 cM in size on the linkage map using a series of congenic strains. This region was contained in a single yeast artificial chromosome that was 220 kb long. This small segment still contained the primary candidate locus Cyp11b1 (11beta-hydroxylase), but the adjacent candidate genes Cyp11b2 (aldosterone synthase) and Cyp11b3 were ruled out. It is concluded that 11beta-hydroxylase, through its known genetic variants altering the production of 18-hydroxy-11-deoxy corticosterone, is very likely to account for the blood pressure QTL on chromosome 7 in the Dahl rat model of hypertension. This QTL accounts for about 23 mm Hg under the condition of 2% NaCl diet for 24 days. |
| High-salt-induced increase in blood pressure: role of capsaicin-sensitive sensory nerves Li, J. and D. H. Wang (2003), J Hypertens 21(3): 577-82. Abstract: OBJECTIVE: To test the hypothesis that sensory afferents are significant functional components in preventing salt-induced increases in blood pressure. DESIGN AND METHODS: Neonatal Wistar rats were subcutaneously injected with 50 mg/kg capsaicin or vehicle on the first and second days of life. After weaning, male rats were divided into three groups and treated for 4 weeks with: control plus normal (0.5%, CON-NS) or high (4%, CON-HS) sodium diet, and capsaicin pretreatment plus HS diet (CAP-HS). Mean arterial pressure (MAP) and its response to bolus injection of calcitonin gene-related peptide (CGRP) and its antagonist, CGRP(8-37), were measured by carotid arterial catheterization. Radioimmunoassay was used to measure CGRP levels in plasma and dorsal root ganglia (DRG). Expression of components of the CGRP receptor, calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein 1 (RAMP1), was determined by the use of Western blot analysis. RESULTS: Baseline MAP was increased in CAP-HS compared with CON-HS and CON-NS rats, and it was higher in CON-HS than in CON-NS rats. MAP response to exogenous CGRP was enhanced in CAP-HS and CON-HS than in CON-NS rats, but MAP response to CGRP(8-37) was increased only in CON-HS rats. Plasma CGRP levels were not different among three groups, but CGRP content in DRG was decreased in CAP-HS compared with CON-HS and CON-NS rats. CRLR expression in mesenteric resistance arteries was upregulated in CAP-HS and CON-HS compared with CON-NS rats, but RAMP1 content was not different among these groups. CONCLUSION: Chronic high-salt intake upregulates expression of mesenteric CGRP receptors without altering CGRP levels in plasma and DRG. Increased expression of mesenteric CGRP receptors may play a counter regulatory role in attenuating salt-induced increases in blood pressure. |
| High-sodium intake prevents pregnancy-induced decrease of blood pressure in the rat Beausejour, A., K. Auger, et al. (2003), Am J Physiol Heart Circ Physiol 285(1): H375-83. Abstract: Despite an increase of circulatory volume and of renin-angiotensin-aldosterone system (RAAS) activity, pregnancy is paradoxically accompanied by a decrease in blood pressure. We have reported that the decrease in blood pressure was maintained in pregnant rats despite overactivation of RAAS following reduction in sodium intake. The purpose of this study was to evaluate the impact of the opposite condition, e.g., decreased activation of RAAS during pregnancy in the rat. To do so, 0.9% or 1.8% NaCl in drinking water was given to nonpregnant and pregnant Sprague-Dawley rats for 7 days (last week of gestation). Increased sodium intakes (between 10- and 20-fold) produced reduction of plasma renin activity and aldosterone in both nonpregnant and pregnant rats. Systolic blood pressure was not affected in nonpregnant rats. However, in pregnant rats, 0.9% sodium supplement prevented the decreased blood pressure. Moreover, an increase of systolic blood pressure was obtained in pregnant rats receiving 1.8% NaCl. The 0.9% sodium supplement did not affect plasma and fetal parameters. However, 1.8% NaCl supplement has larger effects during gestation as shown by increased plasma sodium concentration, hematocrit level, negative water balance, proteinuria, and intrauterine growth restriction. With both sodium supplements, decreased AT1 mRNA levels in the kidney and in the placenta were observed. Our results showed that a high-sodium intake prevents the pregnancy-induced decrease of blood pressure in rats. Nonpregnant rats were able to maintain homeostasis but not the pregnant ones in response to sodium load. Furthermore, pregnant rats on a high-sodium intake (1.8% NaCl) showed some physiological responses that resemble manifestations observed in preeclampsia. |
| Hoe 140 abolishes the blood pressure lowering effect of taurine in high fructose-fed rats Nandhini, A. T. and C. V. Anuradha (2004), Amino Acids 26(3): 299-303. Abstract: High fructose feeding induces moderate increases in blood pressure of normal rats, associated with hyperinsulinemia, insulin resistance and impaired glucose tolerance. Increased vascular resistance, and sodium retention have been proposed to contribute to the blood pressure elevation in this model. Taurine, a sulphur-containing amino acid has been reported to have antihypertensive and antinatriuretic actions. In addition, taurine is shown to increase the excretion of nitrite and kinin availability and hence would be expected to improve the vascular tone. In the present study, the involvement of kinins in the blood pressure lowering effect of taurine was investigated by coadministration of Hoe 140, a kinin B(2) receptor antagonist along with taurine. The effects of taurine on plasma and urinary concentrations of sodium and tissue kallikrein activity were studied in high fructose-fed rats. Fructose-fed rats had elevated blood pressure and decreased levels of sodium in urine. Treatment with 2% taurine in drinking water prevented the blood pressure elevation and coadministration of Hoe 140 abolished this effect of taurine in high fructose-fed rats. The findings confirm the antinatriuretic action of taurine and also suggest a role for the kinins in the mechanism of taurine action in diet-induced hypertension. |
| Home monitoring of blood pressure in pregnancy at high risk of pre-eclampsia Waugh, J., P. Bosio, et al. (2001), Eur J Obstet Gynecol Reprod Biol 99(1): 109-11. Abstract: The early detection of pre-eclampsia is a major challenge in obstetric care. We report a case where pre-eclampsia was detected by home blood pressure monitoring between routine antenatal visits. This novel management approach allows early diagnosis and optimises antenatal care in fulminating disease. |
| Home versus office monitoring of blood pressure: a European multicentre study of high blood pressure Clement, D. L. (1989), J Hypertens Suppl 7(3): S49-51. Abstract: A prospective multicentre study has been set up to examine the following primary questions: (1) Is there a better correlation between blood pressure and mortality, morbidity or organ damage when blood pressure is measured by ambulatory recordings rather than by the usual office method? (2) Is there a difference in the rates of mortality, morbidity and organ damage when treatment is guided by ambulatory values instead of by office values? The aim is to study 2000 patients with primary hypertension, aged 35-70 years, for 5 years. Ambulatory recordings will be made every 6 months. Treatment will be based at random on either office or ambulatory blood pressure readings at each centre. |
| Homeostasis model assessment of insulin resistance, quantitative insulin sensitivity check index, and oral glucose insulin sensitivity index in nonobese, nondiabetic subjects with high-normal blood pressure Kanauchi, M., S. Yamano, et al. (2003), J Clin Endocrinol Metab 88(7): 3444-6. Abstract: To investigate the relationships between high-normal blood pressure (BP) and insulin resistance, we examined insulin sensitivity in 306 nonobese and nondiabetic Japanese subjects with various BP categories (optimal BP, normal BP, high-normal BP, and hypertension). Insulin sensitivity was measured from fasting plasma glucose and insulin values and those during a 75-g oral glucose tolerance test by five formulas: the homeostasis model assessment of insulin resistance (HOMA-R), the quantitative insulin sensitivity check index (QUICKI), the oral glucose insulin sensitivity (OGIS) index, and two insulin sensitivity indexes (ISI-composite and ISI-stumvoll). The HOMA-R was significantly higher, and the QUICKI was significantly lower in subjects with hypertension than in subjects with optimal BP. Both HOMA-R and QUICKI values showed that high-normal BP patients had a higher (but not significant) degree of insulin resistance than optimal BP patients. The OGIS index was significantly lower in subjects with high-normal BP or hypertension than in subjects with optimal BP. The ISI-composite was significantly lower in subjects with high-normal BP or hypertension than in subjects with optimal BP, and it was also significantly lower in subjects with hypertension than in subjects with normal BP. The ISI-stumvoll was significantly lower in subjects with high-normal BP or hypertension than in subjects with optimal BP. The OGIS index, ISI-composite, and ISI-stumvoll significantly decreased with increasing severity of BP status among the normotensive groups (optimal BP, normal BP, and high-normal BP). These findings indicate that insulin resistance is present even in the high-normal BP categories of nonobese and nondiabetic Japanese individuals. |
| Hormonal contraceptives and high blood pressure (author's transl) Coderch Gimeno, J. M. and A. Roca-Cusachs Coll (1979), Med Clin (Barc) 73(2): 77-82. Abstract: The aim of this report is to offer an explanation for the high incidence of arterial hypertension in women taken hormone contraceptives. The real incidence of this association has been considered in women initially having a normal blood pressure and in others who had high blood pressure before using these contraceptives. The estrogen and progestogen components in hormone contraceptives were analyzed individually in various studies. The most recent investigations seem to indicate that progestogen is the main cause of high blood pressure. Different mechanism that could link hormone contraceptives to high blood pressure were investigated. The renin-angiotensin-aldosterone axis involving the action of estrogens and progestogens on the renin substrate, plasma renin, angiotensin II and aldosterone were analyzed. Another possible mechanism could involve glucocorticoids, altering the metabolism of glucose, pyruvate, cholesterol, and triglycerides, Kidney disease involving renal function, microangiopathic anemia, and renal thromboembolism; hyperactivity of the sympathetic nervous system (noraepinephrine and dopamine-beta-hidroxylase blood levels); prostaglandins; genetic mechanism; and individual mechanism were all taken into consideration. Lastly the priorities of the different systems linking high blood pressure to hormone contraceptives and the relationships between them are analyzed. |
| Hormonal responses to treatment of high blood pressure with low-salt diet alone and combined with added potassium Os, I., S. E. Kjeldsen, et al. (1986), Acta Med Scand Suppl 714: 93-7. Abstract: One week strict sodium depletion in essential hypertensive men (n = 17) decreased blood pressure and body weight. Plasma renin concentration increased four-fold (p less than 0.001), plasma noradrenaline with 38% (p less than 0.001), plasma dopamine with 58% while plasma adrenaline remained unchanged. The urinary excretion of vasopressin was reduced with 50% (p less than 0.001). Extra potassium induced only small changes when already sodium depleted. Thus, vasopressin was the only pressor hormone which varied directly with sodium intake, blood pressure and body weight during sodium depletion. |
| Hormonally maintained high blood pressure following adrenalectomy in rats with adrenal-regeneration hypertension and its possible significance in the etiology of that disorder Hall, C. E., O. B. Holland, et al. (1968), Can J Physiol Pharmacol 46(2): 269-74. |