Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BLOOD”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed2001

Delta(9)-THC, 11-OH-Delta(9)-THC and Delta(9)-THCCOOH plasma or serum to whole blood concentrations distribution ratios in blood samples taken from living and dead people.

The recreational use and abuse of Cannabis is continuously increasing in Switzerland. Cannabinoids are very often detected alone or in combination with other drugs in biological samples taken from drivers suspected of driving under the influence of drugs. Moreover, they are also frequently found in blood specimens from people involved in various medico-legal events, e.g. muggings, murders, rapes and working accidents as well. In order to assess the influence of Cannabis exposure on man behavior and performances, it is often needed to estimate the time of Cannabis use. For that purpose two mathematical models have been set up by Huestis and coworkers. These models are based on cannabinoids concentrations in plasma. Because plasma samples are rarely available for forensic determinations in our laboratory, it could be useful to assess the time-laps since Cannabis use through these models from whole blood values. One prerequisite to the use of these models from whole blood values is the knowledge of the plasma to whole blood concentrations distribution ratios of cannabinoids. In this respect, the Delta(9)-THC, 11-OH-Delta(9)-THC and Delta(9)-THCCOOH concentrations were measured in plasma and whole blood taken from eight volunteers who smoke Cannabis on a regular basis. Cannabinoids levels were also determined in "serum" and whole blood samples taken from six corpses. The values of the plasma to whole blood distribution ratios were found to be very similar and their individual coefficient of variation relatively low suggesting that plasma levels could be calculated from whole blood concentrations taken into account a multiplying factor of 1.6. The data obtained postmortem suggest that the distribution of cannabinoids between whole blood and "serum" is scattered over a larger range of values than those determined from living people and that more cannabinoids (mean value of the serum/whole blood concentrations ratios=2.4) can be recovered from the "serum" fraction. The successful use of the mathematical models of Huestis and coworkers may, therefore, rely in part upon the selection of the appropriate blood sample, i.e. plasma. When plasma is not available, whole blood values could be considered with some caution taken into account a multiplying factor of 1.6 to calculate plasma concentrations from blood values. In the case of blood samples taken after death, the use of these models to assess the time of Cannabis use is not recommended.

Dronabinol↗
PubMedDate not supplied

Analysis of forensic specimens for cannabinoids. II. Relationship between blood delta 9-tetrahydrocannabinol and blood and urine 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid concentrations.

Data from five years of gas chromatographic/mass spectrometric (GC/MS) quantitation of blood, or blood and matched (i.e. concurrently collected) urine specimens, for cannabinoids have been used for two distinct evaluations. In the present study, we assessed the relationship of blood delta 9-tetrahydrocannabinol (THC) with blood and urine 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (COOH-THC) concentrations. Cannabinoid-containing (i.e. positive) forensic blood specimens (298, 135 with matched urines) were used to test for correlations and other relationships between these analytes. No correlation was found between blood THC and blood or urine COOH-THC concentrations. Significant correlations were found between the log blood and log urine COOH-THC concentration (r = 0.65). The correlations, however, were neither high nor consistent enough to suggest their use in extrapolations of urine to blood concentrations. Others have suggested that a urine COOH-THC concentration in excess of 100 ng/mL may indicate impairment. We observed this would result in 17% of individuals with blood THC less than 1 ng/mL being classified as impaired. The rate of inaccurate interpretations would increase if higher concentrations of blood THC were considered characteristic of impairment. It has been suggested that a ratio of blood COOH-THC/THC less than 4:1 is an indicator of impairment. In this study, the percentage of bloods with a ratio less than 4:1 increased as THC concentrations increased. However, THC concentrations in excess of 10 ng/mL were required before a majority (70%) of the specimens fell below this ratio, suggesting limitations to its use. Blood metabolic ratios (THC/COOH-THC) displayed a bimodal distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Cannabinoids↗
PubMed1975

Prevention of blood transfusion-induced immunization against transplantation antigens by treatment of the blood with antibody.

The experiments reported show that alloantisera directed against the transplantation antigens of allogeneic blood will completely suppress (1) the lymphocytotoxic antibody response to the blood and (2) its ability to sensitize against renal allografts. AS (Ag-B1) rats injected i.v. with 1 ml of August (Ag-B5) blood gave a strong primary (mainly IgM) and secondary (IgG) lymphocytotoxin response. If the August blood was mixed with AS anti-August serum in vitro before injection, the lymphocytotoxin response was completely suppressed. However, rats given the blood-antiserum mixture gave a primary IgM response upon rechallenge with blood. Rats previously primed with blood had substantial but only partial suppression of the secondary response if the secondary stimulus was given as a blood-antiserum mixture. An AS anti-Wistar (Ag-B2) serum, which showed only weak serological cross-reaction with August lymphocytes, could suppress the lymphocytotoxin response to August blood. A protocol of widely spaced injections of August blood was found to sensitize AS rats to (AS X August)F1 renal allografts. If the blood injections were given as a blood-antiserum mixture, sensitization was prevented. In addition, the blood-antiserum mixtures were found to induce a slight degree of immunosuppression. The clinical application of this approach to preventing blood transfusion-induced sensitization is discussed.

Animals↗
PubMed2000

Prognostic significance of reverse transcriptase-polymerase chain reaction measurement of carcinoembryonic antigen mRNA levels in tumor drainage blood and peripheral blood of patients with colorectal carcinoma.

BACKGROUND: The objective of this study was to assess the prognostic value of detecting circulating tumor cells in the tumor drainage blood and peripheral blood of patients with colorectal carcinoma. METHODS: A total of 53 patients with advanced colorectal carcinoma were studied. Tumor drainage blood and peripheral blood samples that were obtained during surgery were examined for carcinoembryonic antigen (CEA) mRNA using reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: In spiking experiments, the assay indicated a sensitivity limit of 1 carcinoma cell per 10(6) cells. CEA mRNA was detected in the tumor drainage blood of 36 of 53 patients (68%) and in the peripheral blood of 18 of 53 patients (34%). The rate of detection in both tumor drainage blood and peripheral blood was significantly higher in patients with lymph node metastasis, lymphatic invasion, or vascular invasion (P < 0.05). Among those patients who underwent potentially curative resection, the 2-year disease free survival rate of patients whose tumor drainage or peripheral blood was negative for CEA mRNA was significantly better than that of patients who showed CEA mRNA positivity of either sample (tumor drainage blood: 100% vs. 57%; P < 0.05; peripheral blood: 74% vs. 50%; P < 0.01), although the follow-up thus far has been only 9-30 months. CONCLUSIONS: The presence of CEA mRNA in the blood is a useful indicator of circulating tumor cells, and it is one of the determinant prognostic factors for patients with colorectal carcinoma. Moreover, the absence of CEA mRNA in tumor drainage blood was found to be a superior marker for disease free survival compared with that in peripheral blood.

Adult↗
PubMed2002

Umbilical cord blood for unrelated bone marrow replacement; Asia bank and Japan cord blood bank network update.

Cord blood offers many advantages including a high concentration of hematopoietic stem cells, a large number of potential donors, and ease of harvest. Furthermore, since there is no risk for either the mother or baby, few people refuse to donate. There is thought to be a low risk for virus contamination and also probably a low incidence and severity of GVHD. Cord blood can be obtained quickly without the assistance of a coordinator and one or 2 locus-mismatched HLA is usually acceptable. In Japan, there are 10 cord blood banks supported by the government. Between 1996 and June 2002, 9,500 units were registered with the Japan cord blood bank network (JCBBN). 630 units were delivered and most of these were transplanted. The status of registered cord blood units worldwide is shown. 59,081 units have been registered by NETCORD. The Japan cord blood bank network accounts for 13% of these units. I will discuss the Tokyo cord blood tank (TCBB). The bank at Tokyo, to which we belong, is one of the largest banks in Japan. We helped to establish Asia CORD in 2000 and have held annual conferences and meetings in Tokyo to exchange information. So far, China, Korea, Taiwan, Thailand, Viet Nam and Japan have participated. We accepted three trainees from the Ho Chi Minh City Blood Transfusion and Hematology Center for training in cord blood transplantation in May 2001. In January 2002, a patient with ALL received cord blood and was successfully engrafted at Ho Chi Minh City Blood Transfusion and Hematology Center. We present here the clinical outcome of these patients through Tokyo cord blood bank and Japan cord blood bank network. First, the number of CB units stored and registered at JCBBN and TCBB has increased rapidly over the past two years. Second, the survival rate of acute leukemia patients in release was significantly lower than that in patients in CR. Third, the engraftment rate in patients with metabolic disease (50%) was lower than that in patients with leukemia. Fourth, there was no significant difference in the incidence of acute GVHD greater than grade II between patients with a 1-locus and 2-locus mismatch. Finally, the incidence of acute GVHD was relatively low, and there were no deaths related to acute GVHD.

Blood Banks↗
PubMed1985

Disposition of ethanol in maternal blood, fetal blood, and amniotic fluid of third-trimester pregnant ewes.

The disposition of ethanol in maternal arterial blood, fetal arterial blood, and amniotic fluid of nine conscious, cannulated pregnant ewes (128 to 137 days' gestation) was determined for 1-hour maternal intravenous infusion of ethanol, 1 gm/kg maternal body weight. The maternal arterial blood and fetal arterial blood ethanol concentration-time curves were virtually superimposable up to 14 hours. The apparent zero-order ethanol elimination rates for maternal arterial blood and fetal arterial blood were similar. There was a time lag in the transfer of ethanol into amniotic fluid relative to fetal arterial blood, and the peak ethanol concentration in amniotic fluid was significantly lower than the concentrations in maternal arterial blood and fetal arterial blood. The apparent zero-order ethanol elimination rate for amniotic fluid was slower, but not significantly so, compared with the ethanol elimination rates for maternal arterial blood and fetal arterial blood. Ethanol-derived acetaldehyde was found in maternal arterial blood, fetal arterial blood, and amniotic fluid at concentrations at least 1000-fold lower than the respective ethanol concentrations. The data indicate that, for administration of this ethanol dosage regimen to the third-trimester pregnant ewe, there is rapid, bidirectional placental transfer of ethanol; elimination of ethanol from the fetus is regulated primarily by maternal elimination of ethanol; the amniotic fluid may serve as a reservoir for ethanol in utero; and there is appreciable acetaldehyde-metabolizing capacity.

Acetaldehyde↗
PubMed1990

Blood flow and blood volume in a transplanted rat fibrosarcoma: comparison with various normal tissues.

Blood flow measurements following i.v. infusion of iodo-antipyrine labelled with 14C(14C-IAP) and blood volume measurements following i.v. injection of 125I human serum albumin and 51Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14C-IAP was found to be 0.79 +/- 0.07 which is similar to most of the normal tissues studied. The solubility of 14C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours less than 1000 mm3 was found to be 17.9 +/- 4.0 ml blood 100 g tissue-1.min-1. These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. The haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125I-HSA could have accounted for this difference.

Animals↗
PubMed2004

Use of whole blood directly for single-cell gel electrophoresis (comet) assay in vivo and white blood cells for in vitro assay.

The present study investigated the use of whole blood from humans and rats directly for single-cell gel electrophoresis (comet) assay. As little as 20 microl of whole blood was sufficient for comet assay, and the comet images obtained from whole blood were not different from those obtained from isolated lymphocytes. The DNA remained intact up to 4 h at 4 degrees C after isolation and had no observable strand breakage, when whole blood was cryopreserved (at -80 degrees C) in 10% pre-cooled DMSO up to 60 days. To demonstrate that the whole-blood technique could be applied to in vivo studies, we injected rats with a known carcinogen Fe/NTA and measured DNA strand breaks in whole blood in comparison with isolated lymphocytes. We showed that Fe/NTA injection resulted in similar extent of DNA strand breakage in both whole blood and lymphocytes, indicating that whole-blood method can be used for in vivo genotoxic studies. One disadvantage of the whole-blood technique is that whole blood cannot be used for in vitro studies because of the interferences from red blood cell (RBC) components. However, this problem can be overcome by prior hemolysis of RBCs and a brief centrifugation to obtain white blood cells (WBCs), which can then be used for in vitro incubation with genotoxic compounds before comet assay. Overall, this whole-blood technique for comet assay is expected to provide a simple, rapid, and cost-effective alternative for the existing comet assay using isolated lymphocytes in situations such as when time and cost are limiting factors.

Animals↗
PubMed1994

Current role of automated ambulatory blood pressure and self-measured blood pressure determinations in clinical practice.

OBJECTIVE: To discuss the clinical indications for use of automated indirect blood pressure measurement (ABPM) and self-monitoring of blood pressure. DESIGN: Available equipment, variations in blood pressure, and settings in which ABPM may be useful are reviewed. RESULTS: Measurement of blood pressure in the physician's office may not reflect the usual blood pressure in other nonmedical environments, such as at work, at home, or during sleep. Self-measurement of blood pressure at home and work and ABPM can provide this additional information. These procedures can be useful not only for determining the presence of office or "white-coat" hypertension but also for assessing patients with both borderline hypertension in the office and target organ damage, those with drug resistance, and cases of episodic hypertension or hypotension. ABPM can also be used to assess very abrupt changes in blood pressure (hypertension or hypotension) and changes in heart rate and blood pressure during sleep. An abbreviated (6-hour) ABPM can be used to confirm increased office blood pressure measurements. Thus, a 6-hour ABPM has the potential to decrease the misclassification of subjects with hypertension or normotension and to limit costs. CONCLUSION: Accurate self-monitored blood pressure measurements can be integrated with office blood pressure determinations to assist in the management of many patients with hypertension. Both ABPM and self-monitoring of blood pressure can improve blood pressure control and practice efficiencies.

Adult↗
PubMed1997

Gastric inhibitory polypeptide and splanchnic blood perfusion: augmentation of the islet blood flow increase in hyperglycemic rats.

The aim of the study was to investigate how the incretin candidate hormone gastric inhibitory polypeptide (GIP) affects splanchnic blood flow, especially pancreatic islet blood flow. For this purpose, male Sprague-Dawley rats were injected intravenously with either saline or GIP (5 or 15 micrograms/kg body weight) 10 min before blood flow measurements by a microsphere technique. Furthermore, 3 min before the blood flow measurements, 1 ml of either saline or 30% D-glucose was given intravenously. All glucose-injected animals were markedly hyperglycemic (> 20 mmol/liter) at the time of the blood flow measurements. Both doses of GIP potentiated basal and glucose-stimulated insulin release. In the normoglycemic rats, the lowest dose of GIP did not affect the blood perfusion to any of the investigated organs. The highest dose of GIP decreased whole pancreatic and duodenal blood flow, whereas islet blood flow was unaffected. As a result, fractional islet blood flow was increased. In the hyperglycemic rats, where the islet blood flow was increased compared with control animals, both doses of GIP further enhanced islet blood flow. No effect on pancreatic, fractional islet, or duodenal blood flow was seen after GIP administration to hyperglycemic animals. It is concluded that administration of GIP can further augment the glucose-induced stimulation of islet blood flow. This may contribute to facilitating release of insulin from the islets.

Animals↗
PubMed2006

Increased plasma angiotensin II in postural tachycardia syndrome (POTS) is related to reduced blood flow and blood volume.

POTS (postural tachycardia syndrome) is associated with low blood volume and reduced renin and aldosterone; however, the role of Ang (angiotensin) II has not been investigated. Previous studies have suggested that a subset of POTS patients with increased vasoconstriction related to decreased bioavailable NO (nitric oxide) have decreased blood volume. Ang II reduces bioavailable NO and is integral to the renin-Ang system. Thus, in the present study, we investigated the relationship between blood volume, Ang II, renin, aldosterone and peripheral blood flow in POTS patients. POTS was diagnosed by 70 degrees upright tilt, and supine calf blood flow, measured by venous occlusion plethysmography, was used to subgroup POTS patients. A total of 23 POTS patients were partitioned; ten with low blood flow, eight with normal flow and five with high flow. There were ten healthy volunteers. Blood volume was measured by dye dilution. All biochemical measurements were performed whilst supine. Blood volume was decreased in low-flow POTS (2.14 +/- 0.12 litres/m2) compared with controls (2.76 +/- 0.20 litres/m2), but not in the other subgroups. PRA (plasma renin activity) was decreased in low-flow POTS compared with controls (0.49 +/- 0.12 compared with 0.90 +/- 0.18 ng of Ang I.ml(-1).h(-1) respectively), whereas plasma Ang II was increased (89 +/- 20 compared with 32 +/- 4 ng/l), but not in the other subgroups. PRA correlated with aldosterone (r = +0.71) in all subjects. PRA correlated negatively with blood volume (r = -0.72) in normal- and high-flow POTS, but positively (r = +0.65) in low-flow POTS. PRA correlated positively with Ang II (r = +0.76) in normal- and high-flow POTS, but negatively (r = -0.83) in low-flow POTS. Blood volume was negatively correlated with Ang II (r = -0.66) in normal- and high-flow POTS and in five low-flow POTS patients. The remaining five low-flow POTS patients had reduced blood volume and increased Ang II which was not correlated with blood volume. The data suggest that plasma Ang II is increased in low-flow POTS patients with hypovolaemia, which may contribute to local blood flow dysregulation and reduced NO bioavailability.

Adolescent↗
PubMed1999

Relationship between systemic blood pressure, airway blood flow and plasma exudation in guinea-pig.

Plasma exudation in the airways is mainly dependent on microvascular permeability of the tracheobronchial circulation and may be affected by local blood flow. Aortic blood pressure provides the major inflow pressure to tracheobronchial circulation. Therefore, systemically administered vasoconstrictors, in doses enough to increase systemic blood pressure, may theoretically increase the blood flow in the tracheobronchial circulation by enhancing inflow pressure. Consequently, this may influence plasma exudation induced by inflammatory mediators in the airways. To test this hypothesis, we used guinea-pigs to study: (1) the effects of i.v. vasoconstrictors (methoxamine and angiotensin II) on blood flow in the tracheal mucosa and in the leg skeletal muscle (Laser-Doppler flowmetry); (2) the effects of i.v. vasoconstrictors on plasma exudation induced by tracheal administration of the inflammatory mediator bradykinin (150 nmol). We found that i.v. methoxamine and angiotensin II significantly increase tracheal mucosa blood flow and systemic blood pressure. The increase in tracheal mucosa blood flow was, in the case of angiotensin II, found to be significantly related to the increase in systemic blood pressure. In separate experiments, pre-treatment with i.v. methoxamine and angiotensin II significantly potentiates Evan's Blue dye exudation induced by bradykinin in the trachea and main bronchi. We conclude that i.v. methoxamine and angiotensin II potentiate bradykinin-induced plasma exudation in the guinea-pig airways, possibly by increasing the local blood flow. The increase in the local blood flow is most likely induced by enhanced systemic blood pressure (inflow pressure), owing to a redistribution of the total body blood flow.

Angiotensin II↗
PubMed2006

The effect of glucose added to the dialysis fluid on blood pressure, blood glucose, and quality of life in hemodialysis patients: a placebo-controlled crossover study.

BACKGROUND: Risk for hypoglycemia increases during hemodialysis sessions. The compensatory homeostatic response to hypoglycemia may increase the risk for abnormal blood pressure regulation. The purpose is to determine blood pressure and blood glucose levels and variability in these variables during dialysis with and without glucose in the dialysis fluid. METHODS: In a randomized, placebo-controlled, unblinded, crossover study of 44 hemodialysis patients, 34 patients without diabetes and 10 patients with diabetes were allocated to treatment with and without glucose in the dialysis fluid during two 10-week periods. Blood pressure and blood glucose levels were determined 5 to 8 times at each dialysis session during both periods. Quality of life was estimated by using the 36-Item Short-Form Health Survey questionnaire at the end of both treatment periods. RESULTS: With glucose in the dialysis fluid, blood pressure was significantly lower (systolic, 144 +/- 20 versus 149 +/- 21 mm Hg; P < 0.003; diastolic, 73 +/- 10 versus 76 +/- 10 mm Hg; P < 0.001), blood glucose level was higher (125 +/- 25 versus 110 +/- 26 mg/dL [6.96 +/- 1.36 versus 6.08 +/- 1.47 mmol/L]; P < 0.001), and quality of life was the same. Variations in systolic and diastolic blood pressures and blood glucose levels were the same during both treatments. In the subgroup of patients with diabetes, variation in blood glucose levels decreased significantly with glucose in the dialysis fluid (mean, 30 versus 37 mg/dL [1.66 versus 2.03 mmol/L]; P = 0.008). CONCLUSION: Systolic and diastolic blood pressures decreased with glucose in the dialysis fluid in patients with chronic renal failure, presumably because of insulin-induced vasodilatation in patients without diabetes. Blood glucose level regulation improved in the diabetic subgroup, and blood glucose levels were not greater in patients with diabetes with glucose in the dialysis water. Quality of life was not changed.

Adult↗
PubMed2005

Autologous blood donation in cardiac surgery: reduction of allogeneic blood transfusion and cost-effectiveness.

OBJECTIVE: The purpose of this study was to assess transfusion requirements in patients undergoing cardiac surgery with and without autologous blood donation and to calculate the costs of predonation from the hospital perspective. DESIGN: Observational study. SETTING: Single university hospital. PARTICIPANTS: Four thousand three hundred twenty-five patients undergoing elective cardiac surgery with and without autologous blood donation. INTERVENTIONS: Eight hundred forty-nine patients (20%) underwent autologous blood donation, whereas 3,476 (80%) did not. Perioperative allogeneic blood transfusion was recorded as the primary endpoint. To avoid selection bias, patients were stratified according to their preoperative risk score. A decision model was derived from acquired data for the optimization of autologous blood donation. MEASUREMENTS AND MAIN RESULTS: Allogeneic blood transfusion rate was 13% in patients with predonation versus 48% without predonation (p < 0.05). This difference remained statistically significant even after risk stratification. The predonation of 1, 2, or 3 units reduced the probability of receiving allogeneic blood to 24%, 14%, and 9%, respectively. An efficient program of predonation within the department of anesthesiology allowed keeping the costs of predonation low. Decision-tree analysis revealed that predonation of 2 autologous units of blood saved the most allogeneic blood for the smallest increase in costs. Incremental cost for male patients predonating 2 units was dollars 33 (US), whereas for females predonation could be done at no extra cost in comparison to patients without predonation. CONCLUSION: Autologous blood donation significantly reduces allogeneic blood requirement in cardiac surgery. If adjusted for diagnosis and gender, autologous blood donation is a cost-effective alternative to reduce allogeneic blood consumption.

Adult↗
PubMed2000

Influence of blood viscosity on blood flow in the forebrain but not hindbrain after carotid occlusion in rats.

That cerebral blood flow remains unchanged at an increased blood viscosity, as long as the vascular supply is not compromised, was tested. To induce a reduced blood supply of some parts of the brain and to keep the supply unchanged in others both carotid arteries were occluded in anesthetized, ventilated rats. By this procedure, blood supply to the rostral brain, but not to the brainstem and cerebellum, was compromised. Blood viscosity was increased by intravenous infusion of 20% polyvinylpyrrolidone (high viscosity group) or decreased by infusion of 5% albumin (low viscosity group). Cerebral blood flow was measured by the [14C]iodoantipyrine method in 50 complete coronal sections of the rostral brain and 22 complete coronal sections of the brainstem and cerebellum in each rat. In the high viscosity group, mean cerebral blood flow of the rostral brain was significantly lower (46 +/- 7 mL/100 g(-1) x min(-1)) than in the low viscosity group (82 +/- 18 mL/100 g(-1) x min(-1)). No differences could be observed in brainstem and cerebellum between both groups (162 +/- 29 mL/100 g(-1) x min(-1) vs. 156 +/- 18 mL/100 g(-1) x min(-1)). Local analysis of cerebral blood flow in different brain structures of the coronal sections showed the same identical results; i.e., in 29 of the 31 brain structures analyzed in rostral brain, local cerebral blood flow was lower in the high viscosity group, whereas no differences could be observed in the 11 brain structures analyzed in the brainstem and cerebellum. It is concluded that under normal conditions cerebral blood flow can be maintained at an increased blood viscosity by a compensatory vasodilation. When the capacity for vasodilation is exhausted by occlusion of supplying arteries, an increased blood viscosity results in a decrease of cerebral blood flow.

Animals↗
PubMed2004

Wrist blood pressure overestimates blood pressure measured at the upper arm.

OBJECTIVE: Whether blood pressure (BP) measured at the wrist differs from blood pressure measured at the arm is not well known. The aim of this study was to compare the BP readings obtained at the arm with those obtained at the forearm and to assess whether the wrist-arm discrepancies were related to subjects' clinical characteristics. METHODS: We measured blood pressure at the forearm and at the upper arm in 85 subjects using conventional sphygmomanometry. Wrist-arm blood pressure discrepancies were assessed in relation to gender, age, body mass index, skin-fold thickness, arm size, blood pressure level, and arterial compliance measured with the HDI/Pulsewave CR-2000. RESULTS: Blood pressure measured at the wrist consistently overestimated blood pressure taken at the arm with a mean (+/-SD) discrepancy of 8.2 +/- 9.7/9.2 +/- 6.4 mmHg. The systolic blood pressure differences were greater in men than in women (p=0.006) and, among the men, varied according to arm adiposity (positive association, p=0.01). In men, diastolic blood pressure differences correlated with diastolic blood pressure level (negative association, p=0.01). Among the women, only age (p=0.04) was a significant positive independent predictor of the wrist-arm diastolic BP differences. CONCLUSIONS: These results indicate that forearm blood pressure measurement markedly overestimates upper arm blood pressure and that the between-site difference may vary from subject to subject. Wrist blood pressure measurement is not a valid alternative to traditional measurement at the arm and its use should be discouraged.

Adolescent↗
PubMed2006

Use of 24-h ambulatory blood pressure monitoring to assess blood pressure control: a comparison of olmesartan medoxomil and amlodipine besylate.

OBJECTIVE: Olmesartan medoxomil is an angiotensin II receptor blocker with similar antihypertensive efficacy as the calcium channel blocker amlodipine besylate in patients with mild-to-moderate hypertension. In addition to a drug's ability to lower blood pressure, the effectiveness of the agent in enabling patients to achieve specific blood pressure targets is an important clinical consideration. This secondary analysis of a randomized, double-blind study compared the efficacy of olmesartan medoxomil with that of amlodipine besylate in achieving ambulatory blood pressure goals among patients with mild-to-moderate hypertension. METHODS: Following a 4-week placebo run-in, 440 study participants aged >or=18 years were randomized to olmesartan medoxomil (20 mg/day), amlodipine besylate (5 mg/day), or placebo for 8 weeks. The proportion of participants achieving specific systolic and diastolic ambulatory blood pressure goal levels was calculated by dividing the number of participants who had achieved a particular blood pressure goal by the total number of patients in the intent-to-treat population. RESULTS: After 8 weeks of treatment, a mean 24-h ambulatory blood pressure of <130/80 or <130/85 mmHg was achieved by significantly more participants in the olmesartan medoxomil group (18.1 and 30.4%, respectively) than in the amlodipine besylate (7.0 and 14.0%, respectively) or placebo (1.9% for both) groups. The target daytime ambulatory blood pressure of <135/85 mmHg was achieved by more participants in the olmesartan medoxomil group than in the amlodipine besylate group (15.8 vs. 5.8%, respectively; P<0.01). CONCLUSION: In a previous publication of the same study, we demonstrated that starting doses of olmesartan medoxomil and amlodipine besylate produced similar mean reductions in blood pressure. In this subanalysis of the blood pressure data from that primary publication, however, olmesartan medoxomil therapy was shown to result in a greater proportion of patients achieving specific ambulatory blood pressure goals than therapy with amlodipine besylate. As blood pressure goal attainment may be of more direct clinical relevance than numerical blood pressure lowering, the achievement of blood pressure goals should be a key efficacy parameter assessed in clinical trials of antihypertensive medications.

Amlodipine↗
PubMedDate not supplied

A comparison of simultaneously collected arterial, mixed venous, jugular venous and cephalic venous blood samples in the assessment of blood-gas and acid-base status in the dog.

Blood samples were collected simultaneously from the pulmonary artery, jugular vein, cephalic vein, and carotid artery in awake dogs. Blood-gas and acid-base values were measured from these blood samples in normal dogs and in dogs after production of metabolic acidosis and metabolic alkalosis. The values obtained from each of the venous sites were compared with those obtained from arterial blood to determine if venous blood from various sites accurately reflected acid-base balance and could therefore be used in the clinical patient. The results of this study demonstrated significant differences between the blood from various venous sites and the arterial site for PCO2 and pH in all acid-base states. Significant differences for standard bicarbonate (SHCO3) were found only when jugular and cephalic venous blood were compared with arterial blood in dogs with a metabolic acidosis. No significant differences were found for BE when blood from the venous sites was compared with arterial blood. The values for pH, HCO3, TCO2, BE, and SHCO3 measured on blood collected at the various venous sites were found to correlate well with those obtained from arterial blood, with a correlation coefficient of 0.99 for HCO3, TCO2, BE, and SHCO3. These correlation coefficients, together with similar values in BE at all collection sites, indicate that, in the dog with normal circulatory status, blood from any venous site will accurately reflect the acid-base status of the patient.

Acetazolamide↗