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At least 433 records · Page 24Linked to original sources
PubMed2002

Histopathological changes in the tissues under a denture base in experimental osteoporosis with a non-pressure covering or bearing continuous pressure.

In this study, the experimental denture base on the hard palate of the molar region of osteoporotic rats was designed to cover without any mechanical pressure or to load continuous pressure (0.5, 1.5 or 3.4 kPa). Experimental osteoporosis was induced by ovariectomy and feeding on a low calcium diet. Histopathological changes induced by non-pressure covering or continuous pressure in the tissues under the experimental denture bases were examined. Regarding the histological changes induced by continuous pressure, this was evaluated in relation to the time course of the intensity of the continuous pressure. In the tissues under the denture base in osteoporotic condition with non-pressure covering, no histopathological changes caused by non-pressure covering were observed except for a transient slight proliferative reaction in the epithelial ridge. The following histopathological changes were observed in the tissues under the denture base in the osteoporotic condition bearing continuous pressure; (i) bone resorption was induced on the periosteal surface (Ps) in the osteoporotic-3.4 kPa group, and on the pressure side of the endocortical surface (p-Ec) in the osteoporotic-1.5 and -3.4 kPa group, (ii) the appearance of osteoclasts on the p-Ec in the osteoporotic-3.4 kPa group was earlier than that on the Ps in a same group, (iii) bone resorption on the pressure side of the Ec in the osteoporotic-3.4 kPa group manifested at the earlier stage than that in the osteoporotic-1.5 kPa group, (iv) bone formation following bone resorption on the p-Ec was observed more markedly than that on the Ps and (v) histopathological changes in the tissues under the denture base in experimental osteoporosis bearing continuous pressure had an intimate relationship with the initial intensity and the time course of continuous pressure.

Animals↗
PubMed1993

Interaction between intrinsic positive end-expiratory pressure and externally applied positive end-expiratory pressure during controlled mechanical ventilation.

OBJECTIVE: To assess the interaction between intrinsic and externally applied positive end-expiratory pressure (intrinsic PEEP and administered PEEP) in mechanically ventilated patients. DESIGN: Prospective study. SETTING: Intensive care unit of a university hospital. PATIENTS: Twelve consecutive critically ill patients. INTERVENTIONS: Application of an external PEEP of the same value as the intrinsic PEEP. MEASUREMENTS AND MAIN RESULTS: We found that when the administered PEEP was increased from 0 to the baseline value of intrinsic PEEP, mean intrinsic PEEP decreased from 6.5 +/- 4.2 (SD) to 1.3 +/- 0.7 cm H2O (p = .001). The mean end-inspiratory pressure was increased from 20.3 +/- 4.6 to 23.1 +/- 6.1 cm H2O (p < .05). The difference between the modification of intrinsic PEEP and the change in the end-inspiratory pressure was not significantly > 0 cm H2O. Thus, the increase in end-inspiratory pressure may be directly attributable to the increase in total PEEP (administered PEEP plus intrinsic PEEP). None of the other measurements of pulmonary mechanics changed (peak pressure, inspiratory resistance, compliance, and trapped-gas volume). CONCLUSIONS: The administration of positive end-expiratory pressure equal to the intrinsic positive end-expiratory pressure causes the almost total disappearance of the intrinsic positive end-expiratory pressure. When the administered positive end-expiratory pressure does not exceed the intrinsic positive end-expiratory pressure, the former is applied almost in its entirety to the patient's external circuit. The administration of positive end-expiratory pressure without prior quantification of the intrinsic positive end-expiratory pressure results in an overestimation of the beneficial effects of the administered positive end-expiratory pressure on the quasi-static compliance.

Adult↗
PubMed1996

Changes in average blood pressure and incidence of high blood pressure 1983-1984 to 1987-1988 in four population cohorts in the People's Republic of China. The PRC-USA Cardiovascular and Cardiopulmonary Epidemiology Research Group.

OBJECTIVE: To assess comparative changes in systolic and diastolic blood pressure and incidence of high blood pressure over 4 years, and factors related to these changes, in northern and southern, urban and rural adults in the People's Republic of China. SETTING: This is a prospective study of populations surveyed by standardized methods in 1983-1984 and 1987-1988 in north China, Beijing area steel mill workers and farmers, and south China, Guangzhou area shipyard workers and farmers. SUBJECTS: The subjects were 8805 men and women aged 35-54 years at baseline (1983-1984), of whom 7338 were non-hypertensive (systolic blood pressure < 140, diastolic blood pressure < 90 mmHg, not being administered antihypertensive drugs). MAIN OUTCOME MEASURES: The main outcome measures were 4-year changes in systolic and diastolic blood pressures and the 4-year incidence of high blood pressure in persons not hypertensive at baseline. RESULTS: At baseline, the average systolic and diastolic blood pressures were higher for Beijing than for Guangzhou cohorts. At resurvey the average systolic blood pressure had increased for seven of eight sex-city-setting cohorts (all but Guangzhou urban men). The Beijing urban cohorts had the greatest increases (men 6.2 mmHg, women 4.9 mmHg, slopes of 1.6 and 1.2 mmHg/year). The incidence of high blood pressure was higher for Beijing than for Guangzhou cohorts in all four comparisons (men and women, urban and rural). Beijing men, urban and rural, had the highest incidence rates (about 21%). In multiple logistic analyses by sex, variables significantly related to 4-year high blood pressure incidence were city, baseline systolic blood pressure and body mass index, change in weight, and, for men, baseline alcohol use and heart rate. CONCLUSION: Modifiable lifestyle traits, previously shown to be related to blood pressure and high blood pressure in cross-sectional studies, also relate to the incidence of hypertension.

Adult↗
PubMed1998

Home blood pressure measurement has a stronger predictive power for mortality than does screening blood pressure measurement: a population-based observation in Ohasama, Japan.

OBJECTIVE: To compare the predictive powers of self-measurement of blood pressure at home (home blood pressure measurement) and casual (screening) blood pressure measurement for mortality. DESIGN: A prospective cohort study. SUBJECTS AND METHODS: We obtained home and screening blood pressure measurements for 1789 subjects aged > or = 40 years who were followed up for a mean of 6.6 years. The prognostic significance of blood pressure for mortality was determined by the Cox proportional hazards regression model adjusted for age, sex, smoking status, past history of cardiovascular disease, and the use of antihypertensive medication. RESULTS: When the home blood pressure values and the screening blood pressure values were simultaneously incorporated into the Cox model as continuous variables, only the average of multiple (taken more than three times) home systolic blood pressure values was significantly and strongly related to the cardiovascular mortality risk. The average of the two initial home blood pressure values was also better related to the mortality risk than were the screening blood pressure values. CONCLUSIONS: Home blood pressure measurement had a stronger predictive power for mortality than did screening blood pressure measurement for a general population. This appears to be the first study in which the prognostic significances of home and screening blood pressure measurements have been compared.

Adult↗
PubMed2000

Monitoring of intragraft pressure of rejecting organs: increased tissue pressure can be reduced by hyaluronidase therapy.

BACKGROUND: The present study was undertaken in order to: (a) develop a new technique for measurement of interstitial pressure, (b) study the intragraft pressure of rejecting and non-rejecting organs, and (c) study the effect of treatment with the hyaluronan-degrading enzyme hyaluronidase on intragraft pressure. Treatment with hyaluronidase has previously been demonstrated to result not only in reduction of tissue hyaluronan but also in ameliorated interstitial edema, and we suggested that the diminished edema would lead to a reduced interstitial pressure as well. METHODS: At day 5 after syngeneic or allogeneic rat heterotopic heart transplantation, the interstitial pressure of the cardiac grafts was measured using a microtip pressure sensor. Subsequently, the allogeneically grafted animals received a continuous intravenous infusion of either hyaluronidase (total dose: 60,000 U/kg) or vehicle during 2 hr; meanwhile, the interstitial pressure was monitored. RESULTS: The intragraft pressure measurement technique was found to give reproducible results. The interstitial pressure of the rejecting (allogeneic) grafts was considerably higher than that of the non-rejecting (syngeneic), i.e., 12.3+/-1.6 mmHg vs. 1.1+/-0.6 mmHg (P<0.001). Hyaluronidase infusion effectively reduced the interstitial pressure as compared with vehicle treatment. By 20 min, the pressure had been reduced by 28% (P<0.01 compared with vehicle treatment); after 1 hr, by 49% (P<0.001); and after 2 hr, by 68% (P<0.01). CONCLUSIONS: By using modern technology for tissue pressure measurements, we found that the strongly increased interstitial pressure of rejecting organs can be instantly reduced by intravenous administration of the hyaluronan-degrading enzyme hyaluronidase.

Animals↗
PubMedDate not supplied

Blood pressure reactions to stress and the prediction of future blood pressure: effects of sex, age, and socioeconomic position.

OBJECTIVE: This epidemiological study examined whether the magnitude of blood pressure reactions to mental stress was associated with future blood pressure and whether the strength of association was affected by sex, age, and socioeconomic position. MATERIALS AND METHODS: Resting blood pressure was recorded at initial baseline and in response to mental stress. Five-year follow-up resting blood pressure data were available for 990 (68%) of the participants; 333 were 23 years old at the time of stress testing, 427 were 43, and 230 were 63. There were 541 women and 449 men; 440 came from manual and 550 from nonmanual occupation households. RESULTS: Systolic blood pressure reactions to stress correlated positively with follow-up systolic blood pressure; no association was found for diastolic blood pressure reactions and follow-up diastolic blood pressure. In multivariate tests, systolic reactivity remained predictive of follow-up systolic blood pressure and accounted for 2.3% of the variance not explained by age, body mass index, and initial baseline systolic blood pressure. Systolic and diastolic reactivity predicted 5-year upward drift in systolic and diastolic blood pressure respectively, accounting for an additional 3.6% and 2.9% of variance, respectively, in multivariate models. The predictive value of reactivity was greater for participants from manual occupation households and tended to be greater for men. CONCLUSIONS: The results of this study indicate that blood reactions to mental stress predict future blood pressure status and the increase in resting blood pressure over time. The magnitude of the prediction appears to vary with socioeconomic position and sex.

Adult↗
PubMed1994

Proteins under pressure. The influence of high hydrostatic pressure on structure, function and assembly of proteins and protein complexes.

Oceans not only cover the major part of the earth's surface but also reach into depths exceeding the height of the Mt Everest. They are populated down to the deepest levels (approximately 11,800 m), which means that a significant proportion of the global biosphere is exposed to pressures of up to 120 MPa. Although this fact has been known for more than a century, the ecology of the 'abyss' is still in its infancy. Only recently, barophilic adaptation, i.e. the requirement of elevated pressure for viability, has been firmly established. In non-adapted organisms, increased pressure leads to morphological anomalies or growth inhibition, and ultimately to cell death. The detailed molecular mechanism of the underlying 'metabolic dislocation' is unresolved. Effects of pressure as a variable in microbiology, biochemistry and biotechnology allow the structure/function relationship of proteins conjugates to be analyzed. In this context, stabilization by cofactors or accessory proteins has been observed. High-pressure equipment available today allows the comprehensive characterization of the behaviour of proteins under pressure. Single-chain proteins undergo pressure-induced denaturation in the 100-MPa range, which, in the case of oligomeric proteins or protein assemblies, is preceded by dissociation at lower pressure. The effects may be ascribed to the positive reaction volumes connected with the formation of hydrophobic and ionic interactions. In addition, the possibility of conformational effects exerted by moderate, non-denaturing pressures, and related to the intrinsic compressibility of proteins, is discussed. Crystallization may serve as a model reaction of protein self-organization. Kinetic aspects of its pressure-induced inhibition can be described by a model based on the Oosawa theory of molecular association. Barosensitivity is known to be correlated with the pressure-induced inhibition of protein biosynthesis. Attempts to track down the ultimate cause in the dissociation of ribosomes have revealed remarkable stabilization of functional complexes under pseudo-physiological conditions, with the post-translational complex as the most pressure-sensitive species. Apart from the key issue of barosensitivity and barophilic adaptation, high-pressure biochemistry may provide means to develop new approaches to nonthermic industrial processes, especially in the field of food technology.

Bacterial Proteins↗
PubMed1988

Investigations into the origin of the high pressure neurological syndrome: the interaction between pressure, strychnine and 1,2-propandiols in the mouse.

1. The effects of a variety of structural isomers of the centrally acting muscle relaxant mephenesin on the high pressure neurological syndrome have been investigated. Threshold pressures for the onset of the behavioural signs, tremors and convulsions, were established. The effects of these compounds on the response to pressure were also compared with their ability to antagonize the convulsive action of strychnine. 2. The dose-response relationships for strychnine and picrotoxin were investigated at fixed pressures. Additionally, the dose-response relationship of strychnine, in the presence of mephenesin, at pressure was investigated. 3. All the isomers of mephenesin protected against the effects of both pressure and strychnine. The relative potency was found to be identical with respect to both. Mephenesin was clearly the most effective; it raised the threshold pressure for tremors by 2.5 times, that for convulsions elicited by pressure by 1.5 and the ED50 for strychnine convulsions by 1.6 times. Strychnine was found to be strictly additive with pressure whereas picrotoxin exhibited gross deviations from additivity. Mephenesin ameliorated the combined effects of pressure and strychnine equally. 4. The marked dependence on structure of the anticonvulsant activity of the mephenesin isomers can be interpreted as evidence that pressure acts not by some general perturbation of the membranes of excitable cells but rather via some specific interaction. The finding that strychnine and pressure are strictly additive supports the idea of specificity and also indicates that they may share a common mechanism in the production of convulsions. By analogy with the established mechanism of action of strychnine, it is suggested that the hyperexcitability associated with pressure might arise from an action on glycine-mediated inhibitory processes.

Animals↗
PubMed2003

Venous cuff pressures from 30 mmHg to diastolic pressure are recommended to measure arterial inflow by plethysmography.

Venous occlusion strain gauge plethysmography (VOP) is based on the assumption that the veins are occluded and arterial inflow is undisturbed by the venous cuff pressure. Literature is not clear concerning the pressure that should be used. The purpose of this study was to determine the optimal venous occlusion pressure at which the highest arterial inflow is achieved in the forearm, calf, and leg by using VOP. We hypothesized that, for each limb segment, an optimal (range of) venous cuff pressure can be determined. Arterial inflow in each limb segment was measured in nine healthy individuals by VOP by using pressures ranging from 10 mmHg up to diastolic blood pressure. Arterial inflows were similar at cuff pressures between 30 and 60 mmHg for the forearm, leg, and calf. Arterial inflow in the forearm was significantly lower at 10 mmHg compared with the other cuff pressures. In addition, arterial inflows at 20 mmHg tended to be lower in each limb segment than flow at higher cuff pressures. In conclusion, no single optimum venous cuff pressure, at which a highest arterial inflow is achieved, exists, but rather a range of optimum cuff pressures leading to a similar arterial inflow. Venous cuff pressures ranging from 30 mmHg up to diastolic blood pressure are recommended to measure arterial inflow by VOP.

Adult↗
PubMed1988

Transmitral pressure-flow velocity relation. Importance of regional pressure gradients in the left ventricle during diastole.

Effects of regional diastolic pressure differences within the left ventricle on the measured transmitral pressure-flow relation were determined by simultaneous micromanometric left atrial (LAP) and left ventricular pressure (LVP) measurements, and Doppler echocardiograms in 11 anesthetized, closed-chest dogs. Intraventricular pressure recordings at sites that were 2, 4, and 6 cm from the apex were obtained. Profound differences between these sites were noted in the transmitral pressure relation during early (preatrial) diastolic filling. In measurements from apex to base, minimum LVP increased (1.6 +/- 0.7 to 3.1 +/- 0.8 mm Hg, mean +/- SD); the time interval between the first crossover of transmitral pressures and minimum LVP increased (31 +/- 3 to 50 +/- 17 msec); the slope of the rapid-filling LVP wave decreased (74 +/- 13 to 26 +/- 5 mm Hg/sec); the maximum forward (i.e., LAP greater than LVP) transmitral pressure gradient decreased (3.6 +/- 1.3 to 2.1 +/- 0.7 mm Hg); the time interval between the first and second points of transmitral pressure crossover increased (71 +/- 9 to 96 +/- 13 msec); and the area of reversed (i.e., LVP greater than LAP) gradient between the second and third points of transmitral pressure crossover decreased (101 +/- 41 to 40 +/- 33 mm Hg.msec). During atrial contraction, significant regional ventricular apex-to-base gradients were also noted. The slope of the LV A wave decreased (26 +/- 10 to 16 +/- 4 mm Hg/sec); LV end-diastolic pressure decreased (8.1 +/- 2.0 to 7.4 +/- 2.0 mm Hg), and the upstroke of the LV A wave near the base was recorded earlier than near the apex. All differences were significant at the 0.05 level. Simultaneous transmitral Doppler velocity profiles and transmitral pressures were measured at the 4-cm intraventricular site. The average interval between the first and second points of pressure crossover and between the onset of early rapid filling and maximum E-wave velocity were statistically similar (81 +/- 13 vs. 85 +/- 12 msec; NS); and the average area of the forward transmitral pressure gradient associated with acceleration of early flow was significantly greater than the area of reversed gradient associated with deceleration of early flow (133 +/- 36 vs. 80 +/- 46 msec.mm Hg; p less than 0.025).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2005

Genome-wide linkage analysis for loci affecting pulse pressure: the Family Blood Pressure Program.

Pulse pressure, the difference between systolic and diastolic blood pressure, is an independent risk factor for cardiovascular disease. Increased pulse pressure reflects reduced compliance of arteries and is a marker of atherosclerosis. To locate genes that affect pulse pressure, a genome-wide linkage scan for quantitative trait loci influencing pulse pressure was performed using variance components methods as implemented in sequential oligogenic linkage analysis routines. The analysis sample included 10 798 participants in 3320 families who were recruited as part of the Family Blood Pressure Program and were phenotyped with an oscillometric blood pressure measurement device using a consistent protocol across centers. Pulse pressure was adjusted for the effects of sex, age, age2, age-by-sex interaction, age2-by-sex interaction, body mass index, and field center to remove sources of variation other than the genetic effects related to pulse pressure. Significant linkage was observed on chromosome 18 (logarithm of odds [LOD]=3.2) in a combined racial sample, chromosome 20 (LOD=4.4), and 17 (LOD=3.6) in Hispanics, chromosome 21 (LOD=4.3) in whites, chromosome 19 (LOD=3.1) in a combined sample of blacks and whites, and chromosome 7 (logarithm of odds [LOD]=3.1) in blacks from the GenNet Network. Our genome scan shows significant evidence for linkage for pulse pressure in multiple areas of the genome, supporting previous published linkage studies. The identification of these loci for pulse pressure and the apparent congruence with other blood pressure phenotypes provide increased support that these regions contain genes influencing blood pressure phenotypes.

Adult↗
PubMed1991

Independence of pressure reactivity from pressure levels in Tecumseh, Michigan.

The relation between blood pressure level and reactivity to mental arithmetic and isometric exercise was investigated in 169 men and 120 women (average age, 32.3 years) from the village of Tecumseh, Mich. In the entire population, the correlation between baseline blood pressure and blood pressure response to both stressors was not significant. Blood pressure reactivity to both stressors was not increased in participants with borderline hypertension (one clinic reading of more than 140 mm Hg systolic and/or 90 mm Hg diastolic). When subjects were classified according to blood pressure response (below and above the 80th percentile), the hyperreactors to mental and physical stress had normal baseline blood pressure values. The hyperreactors also had clinic-to-home blood pressure differences similar to those of the rest of the population. Participants who had borderline hypertension at age 32 years had significantly elevated blood pressures at ages 5, 8, 12, 21, and 22 years. Those who were hyperreactors at age 32 years had normal blood pressures as children and young adults. Results of the present study lend no support to an association between higher blood pressures and blood pressure hyperreactivity. Study participants in Tecumseh will be recalled for future examinations. The independence of blood pressure levels from blood pressure reactivity offers a unique opportunity to prospectively evaluate their separate effects on cardiovascular morbidity.

Adolescent↗
PubMed1988

Coronary pressure-function and steady-state pressure-flow relations during autoregulation in the unanesthetized dog.

The present study was intended to define the interrelation among endocardial flow, endocardial function, and coronary arterial pressure during spontaneous autoregulation in the left ventricle of chronically instrumented unanesthetized dogs. Steady-state sonomicrometric measurements of regional function and epicardial coronary artery pressure were used to determine the lower pressure limit of endocardial autoregulation while global indexes of myocardial demand remained constant. Transmural wall thickening in the circumflex bed remained unchanged (+/- 5% of control values) until coronary pressure fell below 39 +/- 5.6 (SD) mm Hg. Endocardial segment shortening was similarly constant until coronary pressure fell below 42 +/- 7.4 mm Hg. There was no significant change in endocardial flow as coronary pressure was reduced over the autoregulatory plateau from 84 to 49 mm Hg (1.05-0.99 ml/min/g, p = NS). Below the critical pressure limits, small additional reductions in pressure were associated with marked reductions in both endocardial flow and function. The coronary pressure-function relation was linear as well as steep in this range for both wall thickening (r = 0.94 +/- 0.05) and segment shortening (r = 0.96 +/- 0.03). Although the relation between endocardial flow and function showed more variability than pressure-function relations at low pressures, wall thickening reductions and endocardial flow reductions related on a nearly one-to-one basis. The present study establishes that the coronary pressure-function relation can be used to define the lower limit of endocardial autoregulation. It also indicates that the lower pressure limit of endocardial autoregulation is considerably less than in anesthetized animals (40 vs. 70 mm Hg) and that steady-state flow above this limit is controlled more tightly. Although these differences may relate to systemic hemodynamics, it seems likely that general anesthesia and/or acute surgical instrumentation alter coronary autoregulation under at least some experimental circumstances.

Animals↗
PubMed2001

Carotid pressure is a better predictor of coronary artery disease severity than brachial pressure.

The mechanisms relating pulse pressure to cardiovascular outcome may include surrogacy for coronary disease severity. Although pulse pressure is typically measured at the brachial artery, central pulse pressure and its principal determinant, large-artery stiffness, may relate more closely to disease severity. This study aimed to determine the relationships between large-artery stiffness and carotid and brachial blood pressures and coronary artery disease severity. One hundred fourteen male patients with coronary artery disease (age 60+/-8 years, mean+/-SD) and 57 age-matched healthy male controls (age 59+/-9 years) were recruited. Patients were classified into 2 groups based on the magnitude of their maximum coronary stenosis: moderate (50% to 89%) and severe (>/=90%). Large-artery stiffness was assessed as systemic arterial compliance and carotid-femoral pulse wave velocity. Mean pressure was not different between the 3 groups. Systemic compliance and carotid pulse pressure were significantly different between all 3 groups, with compliance lowest and pressure highest in the severe group (P<0.05). Pulse wave velocity was higher in patients with severe stenosis than in those with moderate stenosis (P<0.01) and those in the control group (P<0.001). Brachial pulse pressure was higher in patients than in controls (P<0.05), but there was no difference between the 2 disease groups. In separate multivariate analyses, carotid pressures and systemic arterial compliance were determinants of coronary artery disease severity, independent of age, smoking status, body mass index, mean arterial pressure, heart rate, cholesterol levels (total, LDL, and HDL), triglycerides, and beta-antagonist and lipid-lowering therapy (P<0.001), whereas brachial pressures and pulse wave velocity were not. In conclusion, central blood pressures and systemic arterial compliance are more sensitive markers of coronary artery disease severity than brachial pressures.

Aged↗
PubMedDate not supplied

[Circadian rhythm of blood pressure and obesity--blood pressure variation and obesity].

INTRODUCTION: The association between obesity and arterial hypertension has been established in a great number of studies. Our objective was to investigate whether circadian rhythm of blood pressure is disturbed among obese people. MATERIAL AND METHODS: In this cros-sectional, randomized study, Schiller BR-102 device was used for ambulatory blood pressure monitoring. One hundred and twenty outpatients were divided into three randomized groups: obese body mass index 30 kg/m2 (52 patients), overweight (28 patients), with body mass index 25.0-29.9 kg/m2 and normal weight (control group) (48 patients), with body mass index 18.5-24.9 kg/m2. In all patients we investigated the following blood pressure parameters: average blood pressure (total, day-time and night-time), maximal blood pressure and dipping or non-dipping blood pressure pattern during night (for systolic and diastolic blood pressure, respectively). RESULTS: In body mass index beyond 30 kg/m2 only systolic blood pressure parameters were significantly higher--average blood pressure--during daytime (P = 0.034) and during night (P = 0.014); maximal blood pressure (P = 0.001). In body mass index beyond 30 kg/m2, absence of normal blood pressure during night was significantly more often registered (P = 0.007). DISCUSSION AND CONCLUSION: The non-dipping blood pressure pattern and increase of systolic blood pressure only reveal hyperactivation of sympathetic nervous system as a leading patophysiological mechanism causing arterial hypertension in obese patients.

Blood Pressure↗
PubMed1992

Definitions and characteristics of salt-sensitivity and resistance of blood pressure: should the diagnosis depend on diastolic blood pressure?

To elucidate the importance of diastolic blood pressure in the definition of salt-sensitive hypertension, we studied 54 male subjects, 36 of whom had untreated, mild essential hypertension. The subjects received a 120 mmol/d Na (as the chloride salt) diet for six days. Thereafter they received a 10 mmol/d Na diet for eight days followed by a 400 mmol/d Na diet for another 8 days. Blood pressure was measured hourly "around the clock" on the last day of each diet; the averaged systolic, diastolic and mean blood pressure values were compared. In 22 subjects diastolic blood pressure increased, when salt intake was increased from 10 to 400 mmol/d. In 18 of these 22 subjects systolic blood pressure increased as well. In 20 subjects, systolic blood pressure increased with salt loading while diastolic blood pressure decreased. In 13 subjects both systolic and diastolic blood pressure decreased with increased salt intake. We defined those subjects showing an increase in diastolic blood pressure as salt-sensitive. If mean blood pressure were used to define salt-sensitivity, 8 of our subjects would have been labeled as salt-sensitive who actually decreased their diastolic blood pressure with salt loading. We suggest that consideration of systolic and diastolic blood pressure responses gives better insight into identifying volume and resistance-related phenomena in salt-sensitive hypertension, than does the consideration of mean blood pressure alone. The definition of salt-sensitivity may require reassessment.

Adult↗
PubMedDate not supplied

Comparison of right atrial pressure and central venous pressures measured at various anatomical locations in children.

PURPOSE: To compare the right atrial pressure to the central venous pressures measured at different points in spontaneously breathing children and try to find a formula to estimate right atrial pressure by central venous pressure measurement. METHODS: Fifty-one children, aged 5 +/- 4.7 years, who underwent right heart catheterization were studied. All patients were sedated and breathed naturally. The mean pressure was the electronic mean of nine heart beats calculated by Philips BC4000 digital angiographic system. Mean pressure of the right atrium was compared to those measured at the high superior vena cava (SVC), low SVC, high inferior vena cava (IVC) (T10-11), middle IVC (L1-2), low IVC (L3-4), and iliac vein (L5-S1). RESULTS: Mean pressures of central veins were significantly higher than that of the right atrium (all p<0.01). Adjusted central venous pressures of SVC-0.5, high IVC-1.5, middle IVC-2, low IVC-2.5, and iliac vein-3 (mmHg) had a good agreement with the right atrial pressure. CONCLUSIONS: Central venous pressures are significantly higher than the right atrial pressure in spontaneously breathing children. Adjusted pressures of SVC-0.5, high IVC-1.5, middle IVC-2, low IVC-2.5, and iliac vein-3 (mmHg) can accurately reflect the right atrial pressure.

Atrial Function, Right↗
PubMed2006

[Measurement and evaluation of home blood pressure monitoring with particular emphasis on evaluating anti-hypertensive effects using a home blood pressure distribution diagram].

Tight blood pressure control over a long period is important to prevent end-organ damage to the brain, heart, and kidneys, and to avoid the complications of hypertension. Control requires an accurate evaluation of treatment through an appropriate monitoring of home blood pressure. In this study, we evaluated a method of home blood pressure monitoring, in which we propose a home blood pressure distribution diagram to evaluate the effectiveness of anti-hypertensive therapy. 1 ) In home blood pressure measurements, the first reading was high, while the second and third readings were essentially similar and thus stable. 2 ) Home blood pressure showed great daily variations, thus necessitating the use of the mean blood pressure over a fixed period, and not the individual blood pressure readings. The mean (morning, mid-day, and evening) over a one-week period was unstable, while the readings were stable over a three-week period. 3 ) The diagrams showing the distribution of home blood pressure measurements obtained in the morning and at night over a long period allowed the degree of early morning hypertension and the effectiveness of long-term blood pressure control to be assessed, and thus were useful for selecting anti-hypertensive agents. 4 ) In elderly patients, a mid-day systolic pressure of 100 mmHg or less (particularly 90 mmHg or less) resulted in the onset of symptoms of excessive hypotensive effects, such as lightheadedness and fainting, which affected ADL and QOL. 5 ) Because of great daily variations, it is difficult to achieve the blood pressure target of 130/80 mmHg or less in patients with hypertension associated with diabetes mellitus or renal insufficiency. 6 ) The home blood pressure distribution diagram facilitated an understanding of the status of anti-hypertensive therapy by patients, and was useful for motivating patients to continue treatment.

Aged↗