Structuring a clinical learning environment for a hybrid-PBL dental curriculum

The standard noninvasive test to assess the severity of peripheral arterial occlusive disease (PAOD) is the ankle/brachial systolic blood pressure index (ABI). While ankle systolic blood pressure is obtained by the Doppler ultrasound technique, brachial systolic blood pressure can be obtained by the Doppler, auscultatory, or oscillometric (Dinamap 1846 SX) methods. The purpose was to determine whether the three methods yielded similar brachial systolic blood pressure values, and consequently similar ABI values, in PAOD patients with intermittent claudication. Fifty patients who had a history of intermittent claudication of 2.3 +/- 2.0 blocks for a duration of 5.7 +/- 5.8 years were recruited. Following 10 minutes of supine rest, brachial systolic blood pressure was measured in the right arm by the three techniques in a randomized order, and ankle systolic blood pressure (87.3 +/- 28.9 mmHg) was measured in the more symptomatic leg with the Doppler technique. Brachial systolic blood pressure was not significantly different (p=0.954) among the Doppler (128.5 +/- 18.4 mmHg), auscultatory (128.4 +/- 17.4 mmHg), and oscillometric (128.2 +/- 17.1 mmHg) methods. Corresponding ABI values also were similar (p=0.922) among the three respective methods (0.68 +/- 0.22, 0.68 +/- 0.22, and 0.68 +/- 0.21), indicating that ABI did not vary according to the technique used to obtain brachial systolic blood pressure. It is concluded that the accuracy of determining ABI in PAOD patients with intermittent claudication was minimally affected by the method chosen to obtain brachial systolic blood pressure.     

Decreased plasma and extracellular volume in growth hormone deficient adults and the acute and prolonged effects of GH administration: a controlled experimental study

OBJECTIVE: There are few data on the endocrine mechanisms underlying the body fluid changes in GH deficiency and their subsequent alteration following GH replacement. We have therefore investigated the time effects of GH on body fluid distribution and fluid regulating hormones in GH deficient adults. DESIGN: The patients underwent in random order four study periods: (1) saline, a 42-hour infusion following 3 weeks without GH, (2) acute GH, a 42-hour GH infusion following 3 weeks without GH, (3) 3 days GH, a 42-hour GH infusion preceded by 3 weeks without GH and 3 days pretreatment with subcutaneous GH injections, (4) 3 weeks GH, a 42-hour GH infusion after at least 3 weeks GH therapy. SUBJECTS: Seven GH deficient adult males and 8 healthy control subjects. MEASUREMENTS: During each infusion period 24-hour blood pressure was recorded, bioimpedance was repeatedly measured and blood samples were obtained every 6 hours. After 41 hours extracellular and plasma volumes were determined isotopically. Extracellular volume, plasma volume and bioimpedance were measured in the control group. RESULTS: GH increased extracellular volume (saline 16.45 +/- 0.79 vs acute GH 16.83 +/- 0.87; vs 3 days GH 17.58 +/- 0.71; vs 3 weeks GH 17.92 +/- 0.88 l, P = 0.01). After 3 weeks of GH, extracellular volumes in the patients and in the control group were identical (control 17.94 +/- 0.32). Plasma volume was increased only after 3 weeks GH treatment (saline 2.93 +/- 0.16 vs acute GH 3.04 +/- 0.22; vs 3 days GH 3.06 +/- 0.07; vs 3 weeks GH 3.37 +/- 0.18 l, P = 0.03), and was decreased compared to the control group (control 3.56 +/- 0.03 l, P < 0.01). Bioimpedance decreased significantly in all treatment periods and was significantly increased compared to the control group. Plasma renin increased during GH administration (saline 16.2 +/- 1.9 vs acute 19.0 +/- 1.9; vs 3 days GH 30.8 +/- 3.0; vs 3 weeks GH 27.0 +/- 3.0 mU/l, P = 0.03), whereas aldosterone and atrial natriuretic factor (ANF) levels remained unaffected by GH. GH caused an increase in systolic blood pressure (BP) and heart rate, whereas diastolic BP remained unaffected. CONCLUSIONS: The present data show that GH deficiency is associated with decreased plasma volume and extracellular volume. GH exposure acutely increases extracellular volume, whereas substitution for a longer time was required to normalize both extracellular and plasma volumes. Renin seems to be involved in these fluid volume regulating effects of GH.     

Age-related and vasomotor stimuli-induced changes in renal vascular resistance detected by Doppler ultrasound

Indirect measurement of renal vascular resistance by duplex Doppler waveform analysis was evaluated in relation to aging and some pathophysiological conditions. Baseline renal resistive index (RRI) (peak systolic frequency shift - lowest diastolic frequency shift/peak systolic frequency shift) was measured in healthy controls aged 20 to 85 years by analyzing the blood flow velocity waveform of interlobar arteries. RRI changes induced by sympathetic activation (cold pressor test and handgrip test) or by fluid load were evaluated. Both repeatability and reproducibility were very good, as the intra and interoperator variations were all less than their reproducibility coefficients. RRI showed a significant increase with aging (ANOVA P < .001), particularly evident in subjects older than 50 years. Both the cold pressor test and handgrip test induced in all the subjects (n = 16) a significant increase in RRI (P < .001), from 0.59 +/- 0.04 to 0.69 +/- 0.04 (12 +/- 6%) for the cold pressor test and from 0.57 +/- 0.03 to 0.66 +/- 0.03 (15 +/- 2%) for the handgrip test. In eight subjects intravenous fluid load (0.25 mL/kg/min of 0.9% NaCl for 120 min) caused a significant decrease in RRI (P < .001), from 0.62 +/- 0.02 to 0.53 +/- 0.01 (17 +/- 2%), which was inversely related to mean blood pressure rise (r = 0.71, P < .001). These data show that pulsed wave Doppler analysis is an accurate method for an indirect evaluation of changes in renal vascular resistance induced by common vasomotor stimuli.     

Cerebral circulation dysfunction and hemodynamic abnormalities in syncope during upright tilt test

OBJECTIVE: To assess the hemodynamic features, including monitoring of cerebral circulation, blood pressure and heart rate, in syncope patients during upright tilt test. DESIGN: Nonrandomized sequential patients with history of syncope of uncertain etiology compared with healthy subjects. SETTING: Noninvasive hemodynamic laboratory of a tertiary referral centre. PATIENTS: Twenty patients with history of syncope and 10 controls without syncope. PROCEDURES: Transcranial Doppler measurement or middle cerebral artery flow velocity, noninvasive and invasive blood pressure monitoring, electrocardiography and pulse oximetry monitoring during upright tilt testing. Measurements were taken in patients at the height of symptoms in supine and upright posture. MAIN RESULTS: Ten patients, while still normotensive, had a drop of 53 +/- 10% (mean +/- SD) in cerebral bloodflow velocity (P = 0.0001) and an increase in heart rate by 58 +/- 35%. The remaining 10 patients had a 58 +/- 15% reduction in cerebral bloodflow velocity (P = 0.0001), a drop in blood pressure of 33 +/- 8% (P = 0.0001) and no change in heart rate. The controls showed no significant changes in cerebral bloodflow velocity and a 25 +/- 12% increase in heart rate (P = 0.0002). CONCLUSIONS: Transcranial Doppler monitoring of cerebral bloodflow velocity during upright tilt testing may improve insight into the complex physiology of syncope.     

Cerebral oxygenation during paediatric cardiac surgery: identification of vulnerable periods using near infrared spectroscopy

OBJECTIVE: To determine the accuracy of three indirect blood pressure monitoring techniques (oscillometric technique [OS], Doppler [DOP], and optical plethysmography [OP] [blood pressure determined with a pulse oximeter waveform]) when compared with direct arterial pressure measurement in cats. STUDY DESIGN: Prospective study. ANIMAL POPULATION: Eight healthy (five female, three male), domestic short-hair cats weighing 3.5 +/- 0.8 kg METHODS: Cats were anesthetized with isoflurane. The inspired concentration of isoflurane was adjusted to produce mild hypotension (80 to 100 mm Hg direct systolic), moderate hypotension (60 to 80 mm Hg direct systolic), and severe hypotension (< 60 mm Hg direct systolic). Indirect pressure measurements were obtained from the thoracic limb and compared with concurrent direct measurement using regression analysis and a modification of Bland and Altman's technique. RESULTS: All three techniques underestimated systolic pressure. OS produced the best prediction of systolic pressure with a bias +/- precision of -15.9 +/- 8.1 mm Hg. DOP and OP were relatively inaccurate with a bias +/- precision of -25 +/- 7.4 mm Hg and -25 +/- 7.5 mm Hg. All three techniques correlated well with direct pressure with r values of 0.81, 0.88, and 0.88 for OS, DOP, and OP. DOP and OP provided an accurate prediction of direct mean arterial pressure with a bias +/- precision of -0.8 +/- 6 mm Hg and 0.6 +/- 5.5 mm Hg. Correlation was good between DOP and mean arterial pressure with r = 0.89. Correlation was also good between OP and mean arterial pressure with r = 0.90. CONCLUSIONS: OS provided the most accurate prediction of direct systolic pressure. DOP and OP provided a good prediction of mean arterial pressure in the cat. CLINICAL RELEVANCE: All three of these techniques are useful for detecting trends. Direct monitoring of blood pressure should be considered if accurate blood pressure measurement is required.     

The clinical utility of a six-minute walk test in peripheral arterial occlusive disease patients

OBJECTIVES: To determine the test-retest reliability of the distance covered and the steps taken to complete a 6-minute walk test by peripheral arterial occlusive disease (PAOD) patients with intermittent claudication. To determine the relationship between the total distance and steps covered during the 6-minute walk test and clinical measures of PAOD severity. DESIGN: Cross-sectional design. SETTING: The Claude Pepper Older Americans Independence Center at the University of Maryland at Baltimore. PARTICIPANTS: Sixty-four PAOD patients between the ages of 45 and 88 years (age = 68 +/- 7 years, ankle/brachial index (ABI) = .61 +/- .19) were recruited from the Vascular Clinic at the Baltimore Veterans Affairs Medical Center and from radio and newspaper advertisements. MEASUREMENTS: Patients were assessed on a 6-minute walk test and a treadmill graded exercise test. A second 6-minute walk test was administered approximately 1 week later. Patients also were characterized in regard to blood pressure in the arms and legs, ABI, anthropometry, body composition, and physical activity. RESULTS: The distances walked during the two 6-minute walk tests were similar (350 +/- 78 m vs 360 +/- 73 m), resulting in a high reliability coefficient (R = .94) and a low coefficient of variation (10.4%). The total steps taken during the 6-minute walk test also were similar (562 +/- 113 steps vs 587 +/- 107 steps), resulting in a high reliability coefficient (R = .90) and a low coefficient of variation (11.7%). Furthermore, the 6-minute walking distance correlated with the distances to onset (r = .346, P = .007) and with maximal claudication pain (r = .525, P < .001) during the treadmill test as well as with ABI (r = .552, P < .001). CONCLUSION: The 6-minute walk test yields highly reliable measurements, which are related to the functional and hemodynamic severity of PAOD, in patients with intermittent claudication.     

Lower extremity arterial evaluation: are segmental arterial blood pressures worthwhile?

PURPOSE: Physiologic observations with blood flow waveform analysis and pressure measurements can document the severity of lower extremity arterial disease. Segmental blood pressures (SEGPs) taken at the thigh, calf, and ankle are commonly used, but their utility has seldom been studied. We quantified improvements in accuracy compared with arteriography when ankle pressures alone (ABI) or SEGP data were added to velocity waveforms obtained by Doppler ultrasound. METHODS: Continuous-wave Doppler velocity waveforms were recorded at common femoral (CFA), popliteal (POP), and dorsal pedal and posterior tibial (TIB) arterial levels. Systolic SEGP data were obtained with appropriately sized upper thigh, upper calf, and ankle cuffs. Waveforms, waveforms plus ABI, and waveforms plus SEGP data from 81 patients were randomly interpreted by 14 technologists or physicians from four institutions blinded to clinical and arteriographic data. Arteriograms were assigned negative or significant, severe (>75% diameter stenosis) values for four segments: iliofemoral (CFA), superficial femoral (SFA), popliteal (POP), and infrapopliteal (TIB) arteries. A total of 9072 segmental interpretations were analyzed. RESULTS: Compared with arteriography, the accuracy of waveform analysis was 83% for severe disease at and proximal to the CFA, 79% for SFA disease, 64% for POP disease, and 73% for TIB disease. Adding ABI improved the accuracy significantly (p < 0.01) to 88% (CFA), 86% (SFA), 70% (POP), and 85% (TIB). Accuracy was inferior when SEGP data replaced ABI: 86% (CFA), 85% (SFA), 70% (POP), and 80% (TIB). CONCLUSIONS: ABIs significantly improved Doppler waveform accuracy at all levels. Compared with ABI, the addition of segmental pressure to waveform data failed to improve accuracy. Pressure measurements above the ankle may lack cost effectiveness and clinical utility.     

Accuracy of a new wrist cuff oscillometric blood pressure device: comparisons with intraarterial and mercury manometer measurements

Accurate measurement of arterial blood pressure is of great importance for the diagnosis and treatment of hypertension. Because of the chronic nature of antihypertensive drug therapy, the involvement of the patient in blood pressure control is desirable. Such an involvement, however, is only feasible if simple, user-friendly, and precise blood pressure measurement devices are available. In this study we tested a new wrist cuff oscillometric blood pressure measurement device in 100 consecutive patients undergoing cardiac catheterization. Blood pressures were simultaneously taken intraarterially (axillary artery) and with a mercury manometer and stethoscope or noninvasive measurement device (OMRON R3). Intraarterial measurements were directly compared with two measurements taken in random order with either an arm cuff mercury manometer or the wrist cuff device. Systolic and diastolic blood pressure as assessed with the mercury manometer was higher, especially when compared with the intraarterial and the wrist cuff values, which were comparable. Correlations of blood pressure values with intraarterial measurement were 0.86 systolic and 0.75 diastolic (P < .01) for the wrist cuff and 0.84 systolic (P < .01) and 0.59 diastolic (P < .05) for the mercury manometer measurements. Reproducibility of both measurements was good for the wrist cuff device ([systolic/diastolic]: r = 0.94/0.92; P < .01) and the mercury manometer (r = 0.97/0.88; P < .01). Both methods overestimated high diastolic values, whereas only the wrist cuff underestimated high systolic values. Thus, the new oscillometric wrist cuff blood pressure measurement device measures arterial blood pressure with great accuracy and reproducibility. As compared with intraarterial values, the wrist cuff device overestimated high diastolic and underestimated high systolic blood pressure values. Blood pressure values as measured by the mercury manometer were higher than intraarterial values and those of the wrist cuff. Both noninvasive devices overestimated high diastolic values.     

Ambulatory 24-h blood pressure monitoring in healthy, middle-aged smokeless tobacco users, smokers, and nontobacco users

Ambulatory 24-h blood pressure monitoring was conducted in 135 healthy, normotensive, middle-aged (35 to 60 years) men, with no antihypertensive medication, to study the influence of habitual smokeless tobacco use (n = 47) and smoking (n = 29) on diurnal blood pressure and heart rate. Comparisons were made with nonusers of tobacco (n = 59). Adjustments were made for differences in age, body mass index, waist-hip ratio, physical fitness, and alcohol intake. Daytime ambulatory heart rates were significantly (P < .05) elevated in both smokeless tobacco users and smokers compared with nonusers (69 +/- 14 and 74 +/- 13 beats/min, respectively, versus 63 +/- 12 beats/min). In subjects > or = 45 years old, ambulatory daytime diastolic blood pressures were significantly elevated, on average by 5 mm Hg, in both smokeless tobacco users and smokers (P < .001) compared with nonusers. Clinical measurements of heart rate and systolic blood pressure in smokers were significantly lower compared with the ambulatory mean values. Nighttime measurements showed only minor differences between the tobacco habit groups. The higher heart rates and blood pressures noted during the daytime in smokers and smokeless tobacco users were most likely due to the effects of nicotine. A strong positive relationship was found between cotinine (major nicotine metabolite) and blood pressure in smokeless tobacco users (systolic blood pressure, r = 0.48, P < .001; diastolic blood pressure, r = 0.41, P = .005), whereas an inverse relationship was found in smokers (systolic blood pressure, r = -0.12, P = .47; diastolic blood pressure, r = -0.03, P = .84), indicating additional and more complex influences on vascular tone in smokers than the influence of nicotine in smokeless tobacco users.     

Metabolic myopathy as a cause of the exercise limitation in lung transplant recipients

BACKGROUND: Cardiopulmonary exercise (CPEx) studies of lung transplant (LTx) recipients have found low maximum oxygen consumptions because of an as yet unexplained mechanism. Although it is likely that a significant problem resides within the mitochondria, this study determines whether a defect in oxygen uptake or utilization is present. METHODS: Six LTx recipients and six age- and sex-matched, healthy control subjects were studied to assess the possibility of a mitochondrial myopathy in LTx recipients. We used standard CPEx testing in conjunction with near-infrared spectroscopy (NIRS), a noninvasive optical technique to assess peripheral oxygen uptake in exercising muscle. NIRS analyzes the absorption spectra of hemoglobin and myoglobin at 760 and 850 nm to determine the relative oxygen saturation of these compounds during exercise with respect to baseline values. Relative changes in oxygen saturation are determined from the application of Beers law to changes in absorbance to compute changes in optical density (deltaOD). The LTx recipients and control subjects performed maximal noninvasive CPEx studies with NIRS analysis of the vastus lateralis muscle. RESULTS: All subjects had a circulatory limitation to exercise. The LTx group had a significantly lower percent predicted maximum oxygen consumption than the control group (45.3%+/-14% vs 100.8%+/-15.6%, [mean +/- SD] P < .001) and earlier onset of the anaerobic threshold (30.3%+/-7.6% vs 60.3%+/-8.0% of predicted VO2max, P < .0001) The LTx recipients demonstrated a significantly smaller deltaOD at maximum exercise as determined by NIRS analysis (0.024+/-0.005 deltaOD vs 0.054+/-0.03 deltaOD, P < .05). CONCLUSIONS: LTx recipients have an impaired maximal exercise capacity because of a disorder of peripheral oxygen utilization. This may be caused by a cyclosporine-induced mitochondrial myopathy.     

Accuracy of portal and forearm blood flow measurements in the assessment of the portal pressure response to propranolol

BACKGROUND/AIMS: The portal pressure response to propranolol varies significantly in individual patients with cirrhosis. At present, propranolol responders can be identified only by measuring the hepatic venous pressure gradient. The aims of this study were: 1) to investigate whether the noninvasive monitoring of portal blood flow by pulsed Doppler ultrasound and forearm blood flow by strain-gauge plethysmography can predict the hepatic venous pressure gradient response to propranolol in patients with cirrhosis, and 2) to analyze the factors that may influence this response. METHODS: Hemodynamic measurements were undertaken in 80 patients with cirrhosis before and after receiving propranolol (0.15 mg/kg i.v., n = 60) or placebo (n = 20). RESULTS: No changes were observed in the placebo group. Propranolol lowered (p < 0.01) hepatic venous pressure gradient from 17.6 +/- 3.8 to 14.7 +/- 3.8 mmHg, portal blood flow from 1122 +/- 363 to 897 +/- 332 ml/min and forearm blood flow from 7.52 +/- 3.1 to 6.12 +/- 2.3 ml/min%. Changes in hepatic venous pressure gradient were correlated (p < 0.01) with those of portal blood flow (r = 0.82) and forearm blood flow (r = 0.54). The reduction in hepatic venous pressure gradient was > 20% in 23 patients ("responders"). The accuracy of portal Doppler flowmetry in identifying responders was higher than that of forearm plethysmography (88.3 vs. 68.3%, p < 0.05). Multivariate analysis proved that previous variceal bleeding was the only factor independently associated with a lack of response to propranolol (relative risk 3.42, 95% CI 1.5-7.4, p < 0.01). Hepatic venous pressure gradient reduction by propranolol was higher in non-bleeders than in bleeders (-19.9 +/- 9.4 vs. -11.3 +/- 8.6%, p < 0.01). CONCLUSIONS: Portal Doppler ultrasound can be used as a reliable surrogate indicator of the hepatic venous pressure gradient response to acute propranolol administration. In addition, our study indicates that this response is mainly influenced by previous variceal hemorrhage.     

Lead levels in deciduous teeth of children from urban and suburban regions in Ankara (Turkey)

PURPOSE: To determine whether hyperglycemia affects pancreatic islet microcirculation in vivo and whether nitric oxide is a mediator. METHODS: Islet blood flow was measured before and after infusion of glucose during in vivo microscopy of mouse pancreatic islet. The pancreas of male BALB/c mice was exteriorized and viewed under the microscope utilizing monochromatic transmitted light. The carotid artery and tail vein were cannulated and systemic blood pressure was monitored continuously. Under fluorescent light, a 0.02 mL bolus of 2% fluorescein isothyocyanate (FITC-albumin) was injected intra-arterially and the first pulse of FITC-albumin through an islet capillary was videorecorded. Following equilibration, either glucose or normal saline 300 mg/g of body weight was given intravenously. Five minutes later, a second bolus was given and the second pulse was videorecorded. The study was repeated in the presence of N omega-nitro-L-arginine methyl ester (L-NAME). The FITC-albumin bolus mean transit time (TT) and observed cross time (OCT) through the islet were calculated using slow-motion video analysis of the recorded images. RESULTS: Infusion of glucose resulted in a significant increase in islet blood flow with no change in systemic blood pressure: baseline TT was 20 +/- 1.3 pixel/0.03 sec and baseline OCT was 0.6 +/- 0.04 seconds; during hyperglycemia, TT was 16.1 +/- 1 pixel/0.03 sec, and OCT was 0.48 +/- 0.03 seconds (n = 11, P < 0.05 versus basal via paired t-test). Continuous infusion of L-NAME negated the effect of hyperglycemia on islet blood flow: baseline TT was 20 +/- 1.8 pixel/0.03 sec and OCT was and 0.6 +/- 0.05 seconds; during hyperglycemia, TT was 20 +/- 1.1 pixel/0.03 sec and OCT was 0.6 +/- 0.33 seconds (n = 10; P < 0.05 versus glucose via unpaired t-test).     

Clinical, biological, and immunophenotypical characteristics of B-cell chronic lymphocytic leukemia with trisomy 12 by fluorescence in situ hybridization

Intra-aortic balloon pumping is frequently used in patients with cardiogenic shock when oliguria persists despite maximal pharmacologic support. The objective of this study was to measure the effect of intra-aortic balloon pumping on renal blood flow, renal oxygen delivery, and renal oxygen consumption in such patients. Central hemodynamics, renal blood flow, and oxygen transport were measured in 10 patients in low cardiac output states. Measurements were made with and without intra-aortic balloon counterpulsation. Renal blood flow was measured by continuous renal vein thermodilution. Small improvements were observed in cardiac output (3.1 +/- 0.8 vs 3.5 +/- 0.8 L/min, P < .01) and pulmonary capillary wedge pressure (22 +/- 5.6 vs 19 +/- 5.3 mmHg, P < .05), but mean arterial blood pressure was unchanged (69 +/- 11 vs 69 +/- 5 mmHg, not significant). Baseline renal blood flow was reduced to approximately 37%, renal oxygen delivery to 31%, and renal oxygen consumption to 60% of normal values. No significant improvement was seen in single-kidney renal blood flow (184 +/- 108 vs 193 +/- 107 mL/min), renal oxygen delivery (28 +/- 16 vs 30 +/- 16 mL/min), or renal oxygen consumption (4.9 +/- 2.0 vs 4.7 +/- 2.5 mL/min) in response to 1:1 counterpulsation. In comparison with measurements made during short-term suspension of counterpulsation, 1:1 aortic balloon pumping failed to result in an increase in renal blood flow, oxygen delivery, or oxygen consumption from the low levels observed in these patients.     

Effect of long-term cocaine administration to pregnant ewes on fetal hemodynamics, oxygenation, and growth

OBJECTIVE: To assess uterine and fetal blood flows by Doppler velocimetry and fetal growth and oxygenation in pregnant ewes treated daily with cocaine and to determine whether cocaine impairs fetal cardiac and cerebral reactivity. METHODS: The study groups received 70 mg (n = 7) or 140 mg (n = 7) of cocaine and the control group (n = 7) received placebo injected intramuscularly daily on days 60-134. Hemodynamic data were measured at rest and during two acute hypoxic tests at cesarean delivery performed on day 134. RESULTS: The fetal heart rate (FHR) and umbilical and uterine resistance indices (RIs) were higher in the cocaine groups than in the control group (FHR: 187 +/- 8 and 166 +/- 8 beats per minute at 83 and 123 days, respectively, in controls and 9-11% higher in cocaine groups; umbilical RI: 0.79 +/- 0.06, 0.60 +/- 0.04, and 0.52 +/- 0.06, at 83, 105, and 123 days, respectively, in controls and 11-17% higher in the cocaine groups [P < .01]; and uterine RI: 0.40 +/- 0.05, 0.40 +/- 0.04, and 0.37 +/- 0.04, at 83, 105, and 123 days, respectively, in controls and 13-35% higher in cocaine groups [P < .05]). At delivery on day 134, the following characteristics were found to be different in the cocaine groups: fetal weight (4.03 +/- 0.2 kg in controls and 15-21% lower in the cocaine groups [P < .02]), partial pressure of oxygen (26.5 +/- 1.4 mmHg in controls and 15-16% lower in cocaine groups [P < .05]), umbilical RI (0.40 +/- 0.03 in controls and 11-17% higher in cocaine groups [P < .01]), cerebral RI (0.61 +/- 0.03 in controls and 9-15% lower in cocaine groups [P < .01]), and cerebral-umbilical ratio (1.52 +/- 0.04 in controls and 22-23% lower in cocaine groups [P < .001]). During the hypoxic tests, the cerebral RI (P < .05) and the cerebral-umbilical ratio (P < .05) decreased significantly less in the two cocaine groups. The FHR response was reduced significantly in the two cocaine groups (P < .05). CONCLUSION: Long-term exposure to cocaine induces uterine and fetal blood flow disorders, fetal growth restriction, and hypoxia. It reduces the capability of the cerebral vessels to vasodilate and the heart rate to increase during acute hypoxia.     

Interactions of lead, calcium, vitamin D, and nutrition in lead-burdened children

This study was undertaken to evaluate relationships between blood or serum levels of lead (Pb), calcium, and 25-hydroxyvitamin D (25-OHD), within the framework of a nutritional survey of lead-burdened children. The results demonstrate that: regardless of blood Pb concentration and season of the year, serum 25-OHD concentration reflects vitamin D intake; high blood Pb (greater than or equal to 60 microgram/dl) was associated with decreased levels of 25-OHD (18+/--1 ng/ml vs. 32+/- in controls, P less than .001); concentrations Pb and calcium were inversely correlated in control and lead-burdened children; and children in the high blood Pb group (greater than or equal to 60 microgram/dl) had lower mean daily intakes of both calcium (610 +/- 20 mg vs. 770 +/- 20 in controls, P less than .001) and vitamin D (210 +/- 17 IU vs. 325 +/- 20 in controls, P less than .001). These data indicate that, in Pb-burdened children, multiple factors modify the absorption and toxicity of Pb, and relative vitamin D deficiency, not excess, is associated with high blood Pb levels. Assessment of nutrition, calcium metabolism, and vitamin D status is recommended in evaluating children known to have undue absorption of Pb.     

Blood pressure measurement in epidemiological studies: a comparative analysis of two methods. Data from the EPIC-Potsdam Study. European Prospective Investigation into Cancer and Nutrition

OBJECTIVE: To investigate the impact of a device replacement in blood pressure measurement in epidemiological studies on comparison and interpretation of epidemiological data by replacing traditional aneroid manometry with automated oscillometric devices. DESIGN: Within the context of a continuing epidemiological study (EPIC-Potsdam Study), blood pressure measurements were performed simultaneously with an aneroid sphygmomanometer and an automated oscillometric device for each subject. We randomly selected 400 men and women from the main study population and one observer performed three consecutive blood pressure measurements for each subject according to a standardized procedure. In total, 10 oscillometric devices of the same type were used. Demographic and anthropometric data for each subject were obtained by trained interviewers. RESULTS: The mean difference between the aneroid and the oscillometric measurements of systolic blood pressure was 0.2 +/- 5.6 mmHg (aneroid value greater, NS), whereas the mean difference in diastolic blood pressure, 0.5 +/- 3.5 mmHg (aneroid value smaller), attained statistical significance (P = 0.0001). Estimates of prevalence for hypertension differed by 0.4% for women, and by 2.9% for men. Associations with the differences between methods were observed with age, blood pressure, lean body mass, upper arm circumference and specific devices without indicating a strong and consistent pattern. CONCLUSIONS: The use of automated oscillometric devices in epidemiological studies introduces a bias of very small magnitude compared with use of the aneroid method. The effect of the change to this automated measurement procedure on prevalence estimates is small but might affect comparability of data. Minor differences in measurement performance between devices of one type might affect population parameters.     

Effect of xuefuzhuyu pill on patients with carotid atherosclerosis by colour Doppler ultrasonography

OBJECTIVE: To observe the effect of Xuefuzhuyu Pill (XFZYP) on carotid atherosclerosis. METHODS: The patients were randomly divided into XFZYP group and aspirin control group. The status of the carotid plaque vessel wall and blood flow were observed by colored Doppler ultrasonography. RESULTS: (1) Plaque of 6 cases regressed, of 6 cases unchanged, of 1 case progressed after treatment of XFZYP. The area of plaques between baseline and after treatment decreased 0.11 +/- 0.05 cm and that of thickness reduced for 0.09 +/- 0.04 cm2 (P < 0.05) in XFZYP group. While plaque of 3 cases regressed, of 6 unchanged, of 2 cases progressed after treatment of aspirin. The area and thickness of plaque were reduced to 0.05 +/- 0.04 cm and 0.04 +/- 0.03 cm respectively. There were no statistic difference in aspirin group. (2) The intima-media thickness of common carotid artery decreased 0.13 +/- 0.03 mm in XFZYP group (P < 0.001 versus baseline), but there were no significant change after treatment of aspirin (P > 0.05). (3) There were no distinct change about peak systole, minimal diastole time average peak, pulsative index, resistive index in common carotid artery and internal carotid artery after treatment of XFZYP and aspirin. CONCLUSION: Colour Doppler ultrasonography of carotid artery provide a noninvasive, safe and valid opportunities for clinical trail. XFZYP can be useful for the treatment of carotid atherosclerosis.     

Comparative accuracy of three automated techniques in the noninvasive estimation of central blood pressure in men

Automated devices have regularly replaced manual sphygmomanometry for the determination of blood pressure not only in homes and clinics, but also in emergency and critical care settings. Few studies exist that correctly assess the accuracy of these devices, and even fewer that specifically compare commercially available units that rely on different physiologic events for measurement. Six hundred pressure measurements were obtained from 120 subjects using 1 of 3 randomly selected blood pressure monitors. In addition, central arterial pressure measurements were obtained simultaneously and directly from the ascending aorta of each subject. Overall, these devices tended to overestimate diastolic (+2.5 mm Hg, p < 0.0001) and mean (+3.8 mm Hg, p < 0.0001) pressures, but not systolic (+0.7 mm Hg, p = NS) pressure. Compared with the other 2 devices, device I, relying on oscillometric detection, demonstrated a significantly smaller mean absolute error for diastolic pressure (4.9 +/- 3.0 vs 7.0 +/- 4.8 and 6.2 +/- 5.3 mm Hg, p < 0.0001) and mean pressure (4.0 +/- 3.2 vs 7.8 +/- 5.9 and 8.6 +/- 7.5 mm Hg, p < 0.0001), and a trend toward smaller error with systolic pressure (6.8 +/- 6.5 vs 7.3 +/- 6.8 and 8.0 +/-5.6 mm Hg, p = 0.19). Clinically significant (+/-10 mm Hg) errors were common with each device (24.8% overall), but serious (+/-20 mm Hg) errors were unusual (3.2%) and did not occur at all with device I during diastolic and mean pressure measurement. All of the devices tested could be expected to perform satisfactorily in most clinical settings provided that an average error of 4.0 to 8.6 mm Hg is tolerable. This level of accuracy typically extended throughout the range of pressures anticipated in most noncritical clinical situations. As implemented in the devices tested, noninvasive measurement by oscillometry with stepped deflation is more accurate than automated auscultation.     

Transmission of hepatitis C virus to infants of human immunodeficiency virus-negative intravenous drug-using mothers: rate of infection and assessment of risk factors for transmission

The acute effects of a newly synthesized thromboxane dual blocker (KDI-792), a combined thromboxane synthase inhibitor and receptor antagonist, on lower limb circulation were examined using two-dimensional color and pulse Doppler ultrasonography and laser Doppler flowmetry. A randomized single-masked, placebo-controlled trial was performed on 36 type 2 diabetic patients with minimally impaired baseline flow. The anatomical cross-sectional area (CSA), maximum flow velocity (MFV) and flow volume index (FVI) in the right dorsal pedis artery (DPA) and right femoral artery (FA) were determined by Doppler ultrasonography before and 45 and 90 minutes after the administration of either 100 or 200 mg of KDI-792 to the dose groups or placebo to the control group. Periflux blood flow (PBF) in the right foot was determined simultaneously by laser Doppler flowmetry. Both CSA and MFV in the dose groups were significantly increased in both the FA and DPA. FVI was markedly increased from 21.4 +/- 3.7 to 68.3 +/- 26.8 in the DPA (M +/- SD, P < 0.01) and from 365.4 +/- 35.3 to 771.7 +/- 75.7 in the FA (P < 0.01) in the 200 mg dose group. In the 100 mg dose group, FVI was markedly increased from 20.0 +/- 8.7 to 68.3 +/- 26.8 (P < 0.01) in the DPA and from 372.5 +/- 130.0 to 677.5 +/- 187.8 (P < 0.01) in the FA. PBF was also increased in both dose groups (from 4.15 +/- 1.4 to 7.0 +/- 4.0 ml/min/100 g tissue in the 200 mg dose group, P < 0.01), whereas there were no significant changes in either measurement in the control group. There were no significant changes in pulse rate or blood pressure after administration in either the dosage group or the placebo group. These and previous findings indicate that a single administration of KDI-792 markedly increases lower limb blood flow and might have a more potent vasodilating effect than that of prostaglandin I2 derivatives.     

Familial hypertrophic cardiomyopathy. Cardiac ultrasonic abnormalities in genetically affected subjects without echocardiographic evidence of left ventricular hypertrophy

AIMS: It is not known whether the apparent normality of echocardiographic examination results, in subjects bearing a mutation for hypertrophic cardiomyopathy but without ultrasonic left ventricular hypertrophy, is due to incomplete phenotypic expression, or inaccurate echocardiographic criteria. The aim of this study was to search for echocardiographic abnormalities in these patients. METHODS AND RESULTS: Echocardiography was performed in 100 subjects from two families with a mutation in the beta-MHC (720) or My-BPC (714) genes. We compared genetically affected subjects with an apparently normal left ventricle (thickness < 13 mm) (20 patients), and nonaffected first-degree relatives (61 normal subjects). (1) Patients had a thicker left ventricular wall (9.7 +/- 1.4 vs 8.9 +/- 1.4 mm, P = 0.03), a greater indexed mass (107 +/- 18 vs 97 +/- 17 g. m-2, P = 0.03), a larger left atrium (27 +/- 9 vs 23 +/- 10 mm3, P = 0.09) and lower wall stress (78 +/- 11 vs 89 +/- 15 10(3) dynes. cm-2, P = 0.002); these differences were highly significant after adjustment for height, age and systolic blood pressure either for wall thickness (P = 0.000003), mass (P = 0.005) or atrial volume (P = 0.001), and the ventricular systolic dimension appeared smaller (P = 0.01); (2) results remained significant (P < 0.01) when a lower cut-off value (< or = 11 mm) or only adults (> or = 18 years) were considered; (3) a subanalysis of Family 714 (13 patients, 25 normals matched for sex, age and height) showed the same trends. CONCLUSION: In familial hypertrophic cardiomyopathy, genetically affected subjects with an apparently normal heart by echocardiography show slight ultrasonic structural and functional left ventricular modifications, suggesting that the phenotype of the disease is a continuous spectrum from normal structure to typical hypertrophy.