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Biomedical subjects

E Vanninen

Publications and source records attributed to E Vanninen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Comparison of HPLC, TLC and minicolumn for measuring the radiochemical purity of 99Tcm-Q12.

TechneScan Q12 (99Tcm-Q12) is a new agent for clinical myocardial perfusion imaging. A product with high radiochemical purity is essential for high-quality imaging. We compared three methods of radiochemical purity analysis for 99Tcm-Q12: thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and minicolumn. Thin-layer chromatography resulted in lower purity (87 +/- 8%) than the minicolumn method (aluminium oxide minicolumn, ethanol) (95 +/- 4%). The HPLC method resulted in the lowest purity (79 +/- 11%). The main impurity was a polar compound, but three further impurities were found using HPLC. Using HPLC, we found the percentage of the parent compound (99Tcm-Q12) in plasma at 40-90 min post-injection to be 19.3 +/- 6.2%. We suggest that gradient HPLC is the most effective method for the analysis of the radiochemical purity of 99Tcm-Q12, and that it can be used to determine the concentration of 99Tcm-Q12 in plasma.

Chromatography, High Pressure Liquid↗
PubMed1998

Acute neurohumoral and cardiovascular effects of idarubicin in leukemia patients.

Idarubicin has been shown to have similar or superior antileukemic activity to daunorubicin with less cumulative cardiotoxicity. However, data of acute cardiovascular effects of idarubicin are scanty but may have clinical significance in predicting late cardiovascular complications. In the present study we evaluated prospectively acute neurohumoral and cardiovascular effects of idarubicin containing induction chemotherapy in 10 patients with newly diagnosed AML or MDS. Idarubicin was administered intravenously 12 mg/m2 on d 1, 3 and 5 as a part of the induction chemotherapy. Serial measurements of plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were performed at baseline and the day following each idarubicin infusion. Echocardiography was performed to assess cardiac systolic and diastolic function. Signal averaged electrocardiography (ECG) was recorded to observe myocardial late potentials associated with possible myocardial injury. In addition, ambulatory ECG recording was performed to assess arrhythmias. Plasma concentrations of ANP increased from 18.2 +/- 1.5 pmol/l to 27.8 +/- 3.5 pmol/l (p = 0.011), to 30.2 +/- 3.0 pmol/l (p = 0.002) and to 40.8 +/- 6.0 pmol/l (p = 0.006) after the first, second and third doses of idarubicin, respectively. Similarly, plasma concentration of BNP increased from 6.2 +/- 1.9 to 9.0 +/- 1.8 pmol/l (p = 0.049) and 17.5 +/- 8.1 pmol/l (p = 0.203) after the first and third idarubicin infusion. Concomitantly, there was a trend towards an increase in left ventricular end diastolic diameter (LVEDD) (50.2 +/- 1.8 to 54.4 +/- 2.2 mm, p = 0.070). The increase in plasma BNP concentrations correlated significantly with the increase in LVEDD (r = 0.624; p = 0.002). No significant ECG changes or arrhythmias were associated with idarubicin infusions except in 1 patient who developed abnormal myocardial late potentials. Our results show that idarubicin causes acute neurohumoral activation associated with increased LVEDD indicating subclinical myocardial dysfunction. Whether these acute changes predict late clinical cardiomyopathy should be evaluated in prospective studies with larger number of patients and with higher cumulative anthracycline doses.

Antibiotics, Antineoplastic↗
PubMed1998

Age and gender dependency of baroreflex sensitivity in healthy subjects.

We evaluated the correlates of baroreflex sensitivity (BRS) in healthy subjects. The study consisted of 117 healthy, normal-weight, nonsmoking male and female subjects aged 23-77 yr. Baroreflex control of heart rate was measured by using the phenylephrine bolus-injection technique. Frequency- and time-domain analysis of heart rate variability and an exercise test were performed. Plasma norepinephrine, epinephrine, insulin, and arginine vasopressin concentrations and plasma renin activity were measured. In the univariate analysis, BRS correlated with age (r = -0.65, P < 0.001), diastolic blood pressure (r = -0.47, P < 0.001), exercise capacity (r = 0.60, P < 0.001), and the high-frequency component of heart rate variability (r = 0.64, P < 0.001). There was also a significant correlation between BRS and plasma norepinephrine concentration (r = -0.22, P < 0.05) and plasma renin activity (r = 0.32, P < 0.001). According to the multivariate analysis, age and gender were the most important physiological correlates of BRS. They accounted for 52% of interindividual BRS variation. In addition, diastolic blood pressure and high-frequency component of heart rate variability were significant independent correlates of BRS. BRS was significantly higher in men than in women (15.0 +/- 1.2 vs. 10.2 +/- 1.1 ms/mmHg, respectively; P < 0.01). Twenty-four percent of women > 40 yr old and 18% of men > 60 yr old had markedly depressed BRS (< 3 ms/mmHg). We conclude that physiological factors, particularly age and gender, have significant impact on BRS in healthy subjects. In addition, we demonstrate that BRS values that have been proposed to be useful in identifying postinfarction patients at high risk of sudden death are frequently found in healthy subjects.

Adult↗
PubMed1998

Regional cerebral blood flow in aneurysmal subarachnoid hemorrhage: single photon emission tomography evaluation of endovascular versus surgical treatment.

Since February 1995, 59 patients with recent aneurysmal SAH have been randomised in our study program, either for surgical aneurysm clipping or for endovascular treatment with Guglielmi detachable coils, to compare the safety and long-term efficacy of these methods. Patients with expansive haematomas or those in a moribund state were excluded, as well as those with aneurysms unsuitable for treatment with both methods. We used single photon emission tomography (SPET) to compare regional cerebral blood flow (rCBF) in surgically and in endovascularly-treated patients. In a sub-study presented in this paper, we analysed the data of patients in Grade I-III (Hunt & Hess) with anterior circulation aneurysms (n = 21). When changes between the pre- and post-treatment rCBF were compared, the surgically treated group showed a tendency towards improved rCBF (change in different vascular territories varied from +4% to +12%) while the endovascularly-treated group showed no consistent change (changes varied from -3% to +6%). There was, however, no significant statistical difference between the changes in the groups. Our results are preliminary, but they suggest that endovascular treatment of anterior circulation aneurysms may not have any advantage over surgical treatment in respect to disturbances in the rCBF.

Cerebrovascular Circulation↗
PubMed1997

Cardiac sympathetic denervation in patients with coronary artery disease without previous myocardial infarction.

Myocardial infarction damages sympathetic nerve fibers coursing through the infarct zone. In this study we investigated whether coronary artery disease without myocardial infarction results in sympathetic denervation. We examined 12 patients without a history of previous myocardial infarction and 19 postinfarction patients. 1-123 metaiodobenzylguanidine (MIBG) and technetium-99m sestamibi (MIBI) single-photon emission tomography were conducted at rest to determine the extent of denervated myocardium and the extent of myocardium with reduced perfusion, respectively. In addition, myocardial perfusion during exercise was assessed with MIBI. A MIBG or MIBI defect was determined as being regional uptake of < or =30% of the maximal myocardial activity. All but 1 patient without previous infarction had MIBG defects. MIBG defects (10.3 +/- 8.5% of left ventricular mass) were significantly larger than MIBI defects at rest (2.4 +/- 3.2%, p <0.001) and during exercise (4.8 +/- 6.1%, p <0.05). In multiregression analysis, the size of an MIBG defect was associated with severity of coronary stenoses (> or =90% of lumen diameter; p <0.05), but not with age, number of significant stenoses (> or =50% of lumen diameter), left main disease, functional class, left ventricular ejection fraction, angina pectoris, maximal ST depression, or mean workload during exercise test. MIBG and MIBI defects were significantly larger in patients with severe coronary stenoses than in patients with moderate stenoses (50% to 89% of lumen diameter) (16.4 +/- 8.9% vs 6.0 +/- 5.2% [p <0.05] and 5.0 +/- 3.1% vs 0.6 +/- 1.3% [p <0.001], respectively). The size of MIBG (16.1 +/- 8.9%) and MIBI defects (7.3 +/- 6.5%) at rest in postinfarction patients did not differ from patients with severe stenoses. Our study demonstrates that cardiac adrenergic tissue is very sensitive to ischemia and that regional cardiac sympathetic denervation can occur in patients with stable coronary artery disease without previous myocardial infarction.

Adult↗
PubMed1997

Striatal and extrastriatal imaging of dopamine D2 receptors in the living human brain with [123I]epidepride single-photon emission tomography.

The iodine-123 labelled ligand benzamide epidepride was evaluated as a probe for in vivo imaging of striatal and extrastriatal dopamine D2 receptor sites in the human brain. Four healthy males were imaged with a high-resolution single-photon emission tomography scanner. Striatal radioactivity peaked at 3 h after injection. The specific binding in the striatum was 0.91+/-0.03 at 3 h and this ratio steadily increased with time. Extrastriatal radioactivity was highest in the thalamus, in the midbrain and in the temporal cortex, and peaked at 45-60 min after injection of tracer. A smaller amount of radioactivity was found in the parietal, frontal and occipital cortices. Two radioactive metabolites were observed, of which one was more lipophilic than the parent compound. The radiation burden to the patient was 0.035 mSv/MBq (effective dose equivalent). The preliminary results showed that [123I]epidepride can be used for imaging striatal and extrastriatal dopamine D2 receptor sites in the living human brain.

Adult↗
PubMed1997

Abnormal myocardial kinetics of 123I-heptadecanoic acid in subjects with impaired glucose tolerance.

Increased triglyceride accumulation has been observed in the diabetic heart, but it is not known whether the abnormalities in myocardial fatty acid metabolism differ between insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetic patients or whether they are present even prior to overt diabetes. Therefore, we studied myocardial fatty acid kinetics with single-photon emission tomography using 123I-heptadecanoic acid (HDA) in four groups of men: impaired glucose tolerance (IGT) (n = 13, age 53 +/- 2 years, mean +/- SEM), IDDM (n = 8, age 43 +/- 3 years), NIDDM (n = 10, age 51 +/- 2 years) and control subjects (n = 8, age 45 +/- 4 years). Echocardiography and myocardial perfusion scintigraphy (IGT and NIDDM groups) were performed to study cardiac function and flow. In the IGT subjects, myocardial HDA beta-oxidation index was reduced by 53% (4.6 +/- 0.4 vs 9.7 +/- 1.0 mumol .min-1.100 g-1, p < 0.01) and HDA uptake by 34% (3.7 +/- 0.2 vs 5.6 +/- 0.3% of injected dose 100g, p < 0.01) compared with the control subjects. The fractional HDA amount used for beta-oxidation was lower in the IGT compared with the control subjects (43 +/- 4 vs 61 +/- 4%, p < 0.05). NIDDM patients also tended to have a lowered HDA beta-oxidation index, whereas IDDM patients had similar myocardial HDA kinetics compared to the control subjects. Myocardial perfusion imaging during the dipyridamole-handgrip stress was normal both in the IGT and NIDDM groups, indicating that abnormal myocardial perfusion could not explain abnormal fatty acid kinetics. In conclusion, even before clinical diabetes, IGT subjects show abnormalities in myocardial fatty acid uptake and kinetics. These abnormalities may be related to disturbed plasma and cellular lipid metabolism.

Adult↗
PubMed1997

Relationship of metabolic variables to abdominal adiposity measured by different anthropometric measurements and dual-energy X-ray absorptiometry in obese middle-aged women.

OBJECTIVES: To investigate how abdominal adiposity assessed by different anthropometric measurements and dual-energy X-ray absorptiometry measurements is associated with metabolic risk factors for cardiovascular disease and non-insulin-dependent diabetes mellitus in obese women. DESIGN: Cross-sectional study. SUBJECTS: Forty-three healthy, obese, middle-aged women (age: 29-64 y, BMI: 28-42 kg/m2). MEASUREMENTS: (1) Anthropometry: waist circumference, waist-to-hip ratio, waist-to-height ratio, abdominal sagittal and transverse diameters and their ratio. (2) Dual-energy X-ray absorptiometry: the amount of total and regional abdominal fat. (3) Metabolic measurements: serum total, VLDL, LDL, HDL cholesterol, triglycerides, fasting and postglucose serum insulin and glucose. RESULTS: After adjustment for age and BMI, all the anthropometric measurements except waist-to-hip ratio and waist-to-height ratio related significantly to HDL and LDL cholesterol. On the other hand, waist-to-hip ratio and waist-to-height ratio showed an association with triglycerides. In addition, all the anthropometric measurements except transverse diameter correlated significantly with fasting insulin and fasting glucose. Waist-to-hip ratio was the only measure that associated with 2 h glucose concentration. The differences between the correlation coefficients were not statistically significant in the z-transformed correlation coefficient test. As to dual-energy X-ray absorptiometry results, the region from the dome of diaphragm to the top of femur ('abdominal fat') and the area between the first and the fourth lumbal vertebrae ('upper lumbal fat') inversely related to HDL cholesterol and positively to triglycerides. Both of these regions correlated significantly with fasting insulin, and "upper lumbal fat' associated also with fasting glucose even after adjustment for age and BMI. CONCLUSION: None of the anthropometric measurements (waist circumference, waist-to-hip ratio, waist-to-height ratio or sagittal diameter) was significantly superior to others to assess the metabolic risk profile. 'Upper lumbal fat' (the area between the first and the fourth lumbal vertebrae) measured by dual-energy X-ray absorptiometry discerned obese women with elevated fasting insulin and fasting glucose.

Absorptiometry, Photon↗
PubMed1997

Are three-dimensional surface-shaded SPET images better than planar and coronal SPET images in the assessment of regional pulmonary perfusion?

Although single photon emission tomographic (SPET) imaging has been shown to be more sensitive than planar imaging in the diagnosis of pulmonary embolism, it has yet to be used routinely in clinical practice. The aims of this study were (1) to compare a new three-dimensional surface-shaded version of SPET (3-D SPET) with conventional planar imaging and coronal SPET slices, and (2) to evaluate observer agreement among these three modalities in the assessment of regional pulmonary perfusion. Compared with a consensus score (based on revised PIOPED criteria) of 29 cases, including nine with a clinical diagnosis of pulmonary embolism, 3-D SPET showed the highest number of normal scans, suggesting better specificity than planar or coronal SPET images. Five observers evaluated the three image sets twice within a 3-6 month period. Agreement with the consensus score was slightly better for the second reading and the average perfect agreement was 71-76%. No one image set was superior to any other in this respect. In conclusion, the number of normal scans using 3-D SPET is significantly greater relative to planar and coronal SPET scans as defined by the consensus view. Observer agreement rates are very similar with all three modalities.

Adult↗
PubMed1997

Periprosthetic bone loss and regional bone turnover in uncemented total hip arthroplasty: a prospective study using high resolution single photon emission tomography and dual-energy X-ray absorptiometry.

Single photon emission computed tomography (SPECT) at 6 and 12 months and dual-energy X-ray absorptiometry (DXA) at 0, 6, and 12 months were performed prospectively in 15 patients who had undergone uncemented total hip arthroplasty (THA) without any complications. Periprosthetic bone mineral density (BMD) decreased significantly in all regions of interests (ROIs) during 1 year of follow-up. The greatest annual decrease was found in the lesser trochanter region (22.1%). From 6-12 months, SPECT activity in the operated side decreased significantly (10-24%) in all ROIs, with the exception of the medial cortex ROI. In contrast, increases (8-36%) were found in the contralateral side. At 12 months, the operated versus control difference was still 10% in the lesser trochanter ROI, but as much as about 70% in the greater trochanter and tip ROIs. The decrease in BMD was significantly related to an increase in SPECT activity in the lesser trochanter region (r = -0.589, p < 0.05). In conclusion, increased periprosthetic SPECT activity seems to be associated with increased bone loss. We suggest that increased SPECT activity and subsequent bone loss reflect altered stress distribution and bone remodeling in the femur after prosthesis implantation.

Absorptiometry, Photon↗
PubMed1996

Measurement of myocardial accumulation of 123I-metaiodobenzylguanidine for studying cardiac autonomic neuropathy in diabetes mellitus.

The association of myocardial 123I-metaiodobenzylguanidine (MIBG) accumulation and autonomic neuropathy, as well as factors known to affect autonomic nervous function, were studied in a group of 12 diabetic patients representing different degrees of autonomic failure. The early myocardial uptake phase of 123I-MIBG was measured by calculating the peak net influx rate for the first 30 min after the 123I-MIBG injection and by single photon emission computed tomography (SPECT) imaging 1 h after the injection. The retainment of 123I-MIBG in the myocardium was measured using SPECT imaging 6 h after the injection, and myocardial uptake and the myocardium/liver uptake ratio were calculated. The 6-h myocardium/liver uptake ratio of 123I-MIBG was significantly (p < 0.05) lower in the diabetic patients with clinically evident autonomic neuropathy compared with those without autonomic neuropathy. Greater body mass index was associated with lower peak net influx rate and 1-h myocardial uptake of 123I-MIBG, and greater diastolic blood pressure was associated with lower 1-h myocardial uptake of 123I-MIBG, whether or not the patients had diabetic autonomic neuropathy. In conclusion, reduction in the 6-h myocardium/liver uptake ratio of 123I-MIBG is related to diabetic autonomic neuropathy. Because the early 123I-MIBG accumulation in myocardium is reduced in diabetic patients with greater body mass index and diastolic blood pressure, irrespective of autonomic neuropathy, our results encourage the use of the late myocardial accumulation of 123I-MIBG for studying sympathetic neuropathy in the diabetic heart.

3-Iodobenzylguanidine↗
PubMed1996

Athletic heart: a metabolic, anatomical, and functional study.

Previous studies have suggested a reduced glucose uptake by the athlete's heart at rest. To examine whether there is a compensatory increase in the myocardial fatty acid utilization, we studied nine male endurance-trained athletes (age 26 +/- 2 yr, VO2max 60 +/- 1 ml.kg-1.min-1, mean +/- SEM) and eight sedentary subjects (age 26 +/- 1 yr, VO2max 38 +/- 2 ml.kg-1.min-1) by single photon emission tomography using 123I-heptadecanoic acid (HDA) and mathematical modeling. Magnetic resonance imaging (MRI) and echocardiography were performed for the measurements of cardiac dimensions and left ventricular (LV) mass. No significant differences were found in the myocardial HDA beta-oxidation index (5.2 +/- 2.0 vs 7.4 +/- 1.6 mumol.min-1.100 g-1, P = NS) between endurance-trained and sedentary subjects. Fractional amounts of HDA beta-oxidation, backdiffusion, and esterification were also similar. In MRI study, LV mass was greater in the trained subjects (213 +/- 9 vs 179 +/- 10 g, P < 0.01) and in particular, LV long-axis diameter measured from the mitral valve level to the apex was increased (102 +/- 2 vs 88 +/- 2 mm, P < 0.001, trained vs sedentary subjects). VO2max correlated with LV long-axis diameter (r = 0.77, P < 0.001). In contrast to our hypothesis, myocardial HDA utilization was not enhanced in endurance-trained athletes at rest. Increases in LV mass and especially in LV long-axis diameter were observed in the athletes, indicating LV longitudinal remodeling.

Adult↗
PubMed1996

Haemodynamic effects of acetazolamide in patients with cardiovascular disorders: correlation with calculated cerebral perfusion reserve.

Individual responses of cerebral blood flow to acetazolamide are highly variable. We hypothesized that this may be due to interactions with cardiovascular diseases and medication. Therefore, we measured the haemodynamic effects of acetazolamide in patients with various cardiovascular disorders and evaluated whether these had any correlation with calculated cerebral perfusion reserve. Ten male patients aged 58 +/- 9 years (mean +/- S.D.) were studied with first-pass radionuclide ventriculography and echocardiography before and 20 min after the administration of 1 g acetazolamide. Systolic blood pressure fell from 133 +/- 21 to 128 +/- 19 mmHg (P < 0.05) and the cardiac output to total blood volume ratio increased from 0.85 +/- 0.18 to 0.92 +/- 0.11 (P = 0.05), indicating a 14% reduction in peripheral vascular resistance. In a further study, 15 patients aged 60 +/- 7 years (22 studies) were studied simultaneously with a nuclear stethoscope and 99Tc(m)-hexamethylpropyleneamine oxime single photon emission tomography before and after acetazolamide administration. The cardiac output ratio increased from 0.81 +/- 0.17 to 0.89 +/- 0.17 (P < 0.05) and showed a significant inverse correlation with calculated cerebral perfusion reserve. In conclusion, acetazolamide increases the cardiac output ratio and reduces systolic blood pressure, indicating reduced peripheral vascular resistance in patients with various cardiovascular diseases and medication. The increase in the cardiac output ratio is inversely related with calculated cerebral perfusion reserve. This helps to explain the high individual variability in calculated cerebral perfusion reserve.

Acetazolamide↗
PubMed1996

Cardiac sympathovagal balance during sleep apnea episodes.

The main acute cardiovascular effects of obstructive sleep apnea syndrome (OSAS) are elevation of blood pressure and reflectory bradycardia, which are followed by an abrupt tachycardia on resumption of breathing. This haemodynamic instability is related to hypoxemia and arousal, and may lead to increased risk from cardiac arrhythmias and sudden cardiac death, as well as to the development of chronic arterial hypertension, in these patients. The aim of this study was to apply frequency domain analysis of heart rate variability (HRV) measured from continuous electrocardiogram (ECG) recordings to evaluate how cardiac autonomic function, and especially cardiac sympathovagal tone, changes during sleep apnea episodes. We identified 41 apneas leading to more than 4%-unit arterial oxygen desaturation in 12 patients (11 men, 1 woman (correction for women), age range 27-67 years). Frequency domain analysis of HRV was performed from ECG recordings using 4 min epochs starting 20 min before apnea began and lasting 20 min after the beginning of apnea. The mean (+/-SEM) fall in oxygen saturation during the apnea was 6.8 +/- 0.6%-units. While high frequency band (HF, reflects cardiac vagal activity) remained unchanged, low frequency band (LF, mainly sympathetic activity) showed a constant increase, leading to significant change in the sympathovagal balance (LF/HF ratio). In conclusion, concordantly with previous peripheral sympathetic-nerve recordings, frequency domain analysis of HRV is able to detect sympathetic activation during sleep apnea episodes, leading to marked change in the sympathovagal balance.

Adult↗
PubMed1996

Ventricular repolarization is correlated with metabolic control in newly diagnosed type 2 diabetes.

Good metabolic control may improve cardiac function in diabetic patients. It is not known, however, whether this functional improvement is associated with concomitant electrocardiographic changes. The aim of the present prospective study was to evaluate the quantitative electrocardiographic and vectorcardiographic correlates of metabolic control, left ventricular function and dimensions, and autonomic nervous function in patients with newly diagnosed Type 2 diabetes. We studied 35 patients (20 men, 15 women; age 52 +/- 6 years (mean +/- SD) with normal electrocardiograms at 1.5 and 15 months after the diagnosis of Type 2 (non-insulin-dependent) diabetes. During the follow-up, body weight decreased, and significant improvement was observed in metabolic control, cardiac function and autonomic nervous function. Concomitantly, maximal spatial vector of T wave increased from 238 +/- 122 to 284 +/- 141 microV (P < 0.01), and this increase was correlated with a decrease in glycosylated haemoglobin A1C (r = -0.45, P < 0.01) and plasma insulin (r = -0.46, P < 0.01). In addition, duration of QRS complex shortened from 94 +/- 9 to 92 +/- 8 ms (P < 0.05), and this shortening was correlated with an increase in heart rate variability (r = -0.34; P < 0.05) and a decrease in peak early to late left ventricular filling flow velocity (r = 0.35, P < 0.05). These changes were most prominent in patients with co-existing hypertension and coronary artery disease. In conclusion, improving metabolic control of diabetes is associated with changes in ventricular repolarization and shortening of QRS complex duration.

Adult↗
PubMed1996

Demonstration of regional sympathetic denervation of the heart in diabetes. Comparison between patients with NIDDM and IDDM.

OBJECTIVE: Global myocardial uptake of 123I-metaiodobenzylguanidine (MIBG) has been shown to be decreased in diabetic patients with autonomic neuropathy, indicating cardiac sympathetic dysfunction. However, possible differences in myocardial MIBG distribution between NIDDM and IDDM diabetic patients are not known. RESEARCH DESIGN AND METHODS: Regional myocardial distribution of 123I-MIBG was studied in seven male IDDM patients (age 45 +/- 2 years, duration of diabetes 30 +/- 3 years, means +/- SE) and 13 NIDDM patients (8 men, 5 women, age 59 +/- 2 years, duration of diabetes 10 +/- 1 years). A dual-tracer single-photon emission tomography was carried out with 123I-MIBG and 99mTc-methoxyisobutylisonitrrile to asses simultaneously myocardial sympathetic innervation and perfusion at rest. Conventional autonomic nervous function tests, power spectral analysis of heart rate variability, and echocardiography were performed for assessments of autonomic function and cardiac dimensions and function. RESULTS: Autonomic nervous function tests and echocardiography showed similar results in IDDM and NIDDM patients. Despite this, global myocardial MIBG uptake (0.43 +/- 0.04 vs. 0.59 +/- 0.06, P = 0.03) and MIBG heart-to-liver ratio (0.59 +/- 0.03 vs. 0.68 = 0.03, P = 0.05) were lower in NIDDM compared with IDDM patients. Regional distribution of MIBG uptake and regional MIBG/perfusion ratio revealed significantly reduced uptake in NIDDM patients especially in the inferoposterior segments of the left ventricle compared with IDDM patients. Difference in age between NIDDM and IDDM patients did not explain the results. CONCLUSIONS: Reduced myocardial MIBG uptake was found in NIDDM patients compared with the uptake in IDDM patients, particularly involving inferoposterior segments. Regional sympathetic damage not detectable with conventional autonomic function tests is relatively common in NIDDM.

3-Iodobenzylguanidine↗
PubMed1995

Effect of posture on baroreflex sensitivity in healthy subjects.

In this study we investigated whether body position has significant effects on baroreflex sensitivity in healthy subjects. Baroreflex sensitivity was calculated from pressure overshoot after the release of a Valsalva strain in the supine and sitting positions in 10 subjects. At rest, no difference was found in supine and sitting mean R-R intervals (837 +/- 82 and 858 +/- 86 ms, respectively), whereas systolic and diastolic blood pressures were lower in the supine position (111.3 +/- 24.6 vs. 141.2 +/- 12.6 mmHg, P < 0.01 and 54.8 +/- 14.7 vs. 75.6 +/- 13.4 mmHg, P < 0.001, respectively). Baroreflex sensitivity in the supine (9.0 +/- 4.1 ms x mmHg-1) and sitting positions (8.8 +/- 4.9 ms x mmHg-1) did not differ significantly from each other. The correlation between supine and sitting baroreflex sensitivity was 0.96 (P < 0.001) and in 9 out of 10 subjects the discrepancy between supine and sitting baroreflex sensitivity was < 2.0 ms x mmHg-1. We conclude that baroreflex sensitivity measured in the supine and sitting positions do not differ significantly from each other.

Adult↗