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Biomedical subjects

B Erbas

Publications and source records attributed to B Erbas.

At least 37 records · Page 2Linked to original sources
PubMed1993

Short-term effects of somatostatin analogue (SMS 201-995) on left ventricular function in healthy persons: a scintigraphic study.

Since somatostatin has been reported to have a negative inotropic and chronotropic effect on atria and positive inotropic effect on ventricle, present study was designed to investigate the acute effects of somatostatin analogue SMS 201-995 infusion on the left ventricular function in healthy volunteers. After labeling the autologous red blood cells with 750-1000 MBq 99mTc-pertechnetate, ECG-gated radionuclide ventriculography was performed. Using Fourier analysis of the left ventricular time-activity curve, ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), time to end-systole (TES) and normalized TES/T values were calculated. Study group consisted of 12 healthy volunteers. Somatostatin analogue SMS 201-995 infusion was given at a rate of 100 micrograms/h during 2h. Baseline, 1st, 2nd h and 4th h imagings were done using the same protocol. Simultaneously heart rate and blood pressure were recorded. The difference between parameters was tested using Kruskall-Wallis test. The mean heart rate, systolic and diastolic blood pressures and did not show any statistically significant change during the somatostatin analogue infusion and 2h later in comparison to baseline values. The mean PER and PFR had a slight decrease at the first hour of infusion, but the change was not significant. However, the significant correlation of PER values with heart rate, EF and TES observed at baseline study were disappeared during the infusion. These results indicate that somatostatin analogue infusion does not appear to change the left ventricular systolic and diastolic function in healthy persons significantly.

Adult↗
PubMed1993

Scintigraphic evaluation of reduced-size liver transplant from living related donor in Byler's disease.

Byler's syndrome is a rare form of autosomal recessive intrahepatic cholestasis that is fatal in children. A 10-year-old girl diagnosed with Byler's syndrome underwent reduced-size liver transplantation using lateral segments of her living mother's liver. The donor's and the recipient's liver functions after transplantation were evaluated using Tc-99m disofenin and Tc-99m SC to investigate morphology, liver perfusion, and hepatobiliary function.

Child↗
PubMed1993

Quantification of central benzodiazepine receptor binding potential in the brain with 123I-iomazenil SPECT: technical and interobserver variability.

Factors contributing to the quantification of the central benzodiazepine receptor binding potential in vivo using 123I-iomazenil and single photon emission computed tomography (SPECT) were analysed in phantom studies and in volunteers. SPECT was performed with the SME810 multidetector system. The Hoffman three-dimensional brain phantom was used to investigate linearity and reproducibility of SPECT results using different 123I activity concentrations. Dynamic and multislice SPECT scans were performed in nine healthy volunteers between 0 and 270 min after injection of 110 MBq 123I-iomazenil. Displacement studies were performed in three volunteers using 1 mg flumazenil administered intravenously (i.v.) at 250 min postinjection (p.i.). Regions of interest (ROIs) over the cerebral cortex and various subcortical nuclei were either fixed areas based on a stereotaxic brain atlas, or manually drawn, based on 60% isocontour lines. Interobserver variability of the ROI data and ratios derived from those data were estimated for two independent observers. The brain phantom measurements showed linearity with respect to 123I concentration and good reproducibility. The interobserver study showed a reasonable interobserver reliability for the large fixed ROIs. The displacement study showed about 50% displacement in all ROIs. Concentrations of 123I-iomazenil in the brain can be measured reliably with the SME810. Large fixed ROIs based on a stereotaxic atlas may be used reliably for quantification. The level of 4 cm above the cantomeatal line does not provide a useful reference region with a very low central benzodiazepine receptor binding potential.

Adult↗
PubMed1993

Scintigraphic evaluation of functional renal reserve using angiotensin-converting enzyme inhibition in patients with type II diabetes mellitus.

Acute effects of 20 mg oral enalapril (E), and angiotensin-converting enzyme inhibitor, on renal function and the renin-angiotensin-aldosterone system were investigated in 13 patients with type II diabetes mellitus (8 female, 5 male) and 10 hypertensive controls using a radionuclide method. Plasma glucose control was evaluated with fructosamine (F) determinations. After intravenous administration of 370 MBq 99mTc-DTPA, sequential images were recorded. Glomerular filtration rate (GFR), perfusion index (PI), time to maximum activity and reno index values of the kidneys were calculated. Two days later, renal scintigraphy was repeated after oral administration of E. Plasma levels of renin, angiotensin II and aldosterone were analyzed using RIA. Basal GFR values (mean: 92.6 ml/min) correlated with F (r = 0.364; p < 0.05). In the diabetic group, 5 patients had a decrease in GFR and an increase in PI after oral E. The mean percent change of GFR was 12 +/- 32 for patients and 20 +/- 12 for controls, respectively. Percent change of GFR had a slightly negative correlation with F values (r = -0.51; p < 0.05) and with PI (r = -0.65; p < 0.001). The patients with good metabolic control had an increase in GFR and a decrease in PI indicating an increase in renal blood flow and glomerular filtration. In patients with proteinuria and poorly controlled diabetes, in response to E-induced efferent arteriolar dilation, there is a decrease in GFR and an increase in PI which indicates a fall in filtration and renal blood flow. This glomerular hemodynamic pathology precedes morphological changes due to diabetes.

Adult↗
PubMed1993

Scintigraphic evaluation of the short- and long-term renal effects of oral felodipine using technetium-99m-mercaptoacetyl triglycine.

The short- and long-term effect of felodipine on renal perfusion and tubular function was investigated using a new renal tubular imaging agent, 99mTc-mercaptoacetyl triglycine (99mTc-MAG3). Twelve patients with essential hypertension (mean age = 49 +/- 8 years) were studied. Renal scintigraphies with 180 MBq 99mTc-MAG3 were performed at baseline, at the 2nd hour following oral administration of 5 mg felodipine and 4 weeks later on 5-10 mg daily felodipine therapy. The time-activity curves of each kidney were obtained following background subtraction. The 99mTc-MAG3 clearance value was measured for each kidney. In addition, perfusion index (PI), reno index, time to maximum, half-maximum and two thirds of maximum activity values of each kidney were calculated. Systolic and diastolic blood pressures were significantly lowered with long-term administration of felodipine (from 159 +/- 12/105 +/- 5 to 141 +/- 11/87 +/- 7 mm Hg, p = 0.01 and p = 0.002, respectively). Heart rate did not change significantly. Initially, a decrease in PI indicating an increase in renal blood flow (from 246 +/- 96 to 194 +/- 54, p = 0.01) was observed, whereas no change was noted during the chronic administration (to 230 +/- 69, p = NS). Total clearance of 99mTc-MAG3 was decreased nonsignificantly following the initial dose of felodipine (from 361 +/- 93 to 351 +/- 91 ml/min, p = NS). During long-term therapy, felodipine did not alter the perfusion and tubular function of the kidneys. Our results indicated that felodipine causes a significant increase in renal blood flow initially, even with a nonsignificant change in systemic blood pressure.

Administration, Oral↗
PubMed1993

Alterations in left ventricular function in patients with Behçet's disease using radionuclide ventriculography and Doppler echocardiography.

Behçet's syndrome is a multisystem disease; however, cardiac involvement in this disorder has been relatively less recognized. Noninvasive imaging methods may reveal a cardiac disorder which has not manifested itself clinically. In this study, radionuclide ventriculography and Doppler echocardiography were performed in 24 patients with Behçet's disease to assess the left ventricular systolic and diastolic function. Patients had neither known heart disease nor cardiac symptoms. Radionuclide ventriculography was performed using 99mTc-labeled red blood cells. Ejection fraction (EF), EF fraction in the first 100 ms (EFV), peak ejection rate, time to peak ejection, 1/3 EF, time to end systole, peak filling rate (PFR), time to peak filling and 1/3 filling fraction (1/3 FF) values were computed using Fourier analysis of the time activity curve of the left ventricle with 3 harmonics. Doppler echocardiography (DE) has described impairment of diastolic compliance using analysis of mitral flow. The mean EF (54.7 +/- 9%), EFV (11.6 +/- 3.6%), PFR (2.49 +/- 0.58 EDC/s) and 1/3 FF (33.64 +/- 14%) values were significantly lower in patients than those of the control group. Nine (37.5%) patients demonstrated an impairment of diastolic function and 3 (12.5%) had abnormal systolic function observed by the radionuclide method. DE showed abnormal ventricular compliance in 13.6% of patients. As a conclusion, noninvasive imaging methods such as radionuclide ventriculography and DE may be valuable to detect diastolic impairment as an early sign of cardiac involvement in Behçet's disease.

Adult↗
PubMed1993

Changes in the circulating endothelin and atrial natriuretic peptide levels during coronary artery bypass surgery.

To evaluate the behavior of circulating endothelin and atrial natriuretic peptide (ANP) during coronary artery bypass graft (CABG) surgery, blood samples from patients with coronary artery disease (n = 8) were investigated before, during and after operation. Plasma levels of endothelin and ANP were determined using the radioimmunoassay method. Baseline plasma levels were compared to those of normal volunteers (n = 6). Left ventricular function at rest and as a response to isometric exercise was evaluated using radionuclide ventriculography before and after coronary bypass surgery. The mean endothelin value was found to be within normal limits, however the mean ANP value was slightly higher than control. Patients had significantly improved left ventricular systolic and diastolic function after surgery. The mean endothelin level was higher than initial values immediately after extra-corporeal circulation and returned to initial values in two hours. However, ANP values were increased and remained higher than initial values. Baseline endothelin values were negatively correlated with systolic function parameters, whereas endothelin and heart rate had a positive correlation before extra-corporeal circulation. Coronary artery bypass graft surgery may cause an increase in the circulating endothelin level either due to endothelial injury or due to myocardial ischemia and hypothermia. Following surgery, increased endothelin levels returned to normal values immediately.

Aldosterone↗
PubMed1993

Comparison of metoclopramide and erythromycin in the treatment of diabetic gastroparesis.

OBJECTIVE: To compare the effects of erythromycin and metoclopramide on gastric emptying and symptoms of gastroparesis in diabetic patients with delayed gastric emptying. RESEARCH DESIGN AND METHODS: The study group consisted of 13 patients with symptoms of severe gastroparesis and delayed gastric emptying. Gastric emptying was evaluated using a radionuclide method, and gastrointestinal symptoms were scored. The patients were given either erythromycin (250 mg 3 times/day) or metoclopramide (10 mg 3 times/day) in random order for 3 wk, and after a washout period of 3 wk they were crossed-over to the other medication for another 3 wk. Parameters of gastric emptying were assessed before treatment and after both erythromycin and metoclopramide administration. RESULTS: The half-time of gastric emptying in diabetic subjects was 110 (77-120) min before treatment. At 60 and 90 min, the median value of residual isotope activity was 66.5 (55-83.5) and 55% (43-74.3), respectively. The half-time decreased to 55 min (28.6-115) after 3 wk of treatment with erythromycin and percentages of meal retention in the stomach at 60 and 90 min were 49.9 (38.4-70) and 40.5% (29.7-60), respectively. After taking metoclopramide, the median value of half-time was 67 min (15-115) and percentages of meal retention at 60 and 90 min were 51 (34.5-93.9) and 42% (24-71.2), respectively. When compared with baseline values a significant difference in gastric emptying parameters was found after both erythromycin and metoclopramide. A significant improvement of the total score for gastrointestinal symptoms was observed with both drugs, but this improvement was more pronounced with erythromycin. CONCLUSIONS: Erythromycin, a macrolide antibiotic and a motilin receptor agonist, appears to stimulate intestinal motility and seems to be an alternative agent for the treatment of gastroparesis caused by diabetic autonomic neuropathy.

Administration, Oral↗
PubMed1992

Uterine technetium-99m mercaptoacetyltriglycine and diethylene triamine penta-acetic acid uptake in the scintigraphic evaluation of transplanted kidneys.

An anuric 35-year-old woman with a renal transplant underwent serial renal scintigraphy studies to screen the kidney function. A hypervascular pelvic mass in the region of the bladder was identified during technetium-99m mercaptoacetyltriglycine (MAG3) and also during 99mTc diethylene triamine penta-acetic acid (DT-PA) scintigraphy. She was in the secretory phase of the uterine cycle during the study and had no gynaecological problem to explain the radioactivity accumulation. The accumulation of 99mTc-MAG3 mimicking the bladder was considered as uterine activity. To our knowledge, this is the first case of uterine visualization with 99mTc-MAG3.

Adult↗
PubMed1992

Assessment of changes in regional cerebral blood flow in patients with major depression using the 99mTc-HMPAO single photon emission tomography method.

Regional cerebral blood flow was investigated in 14 patients with major depression diagnosed according to the DSM-III-R criteria (six patients with single and eight patients with recurrent episodes) and in ten healthy volunteers. The mean ages of the patients and the controls were 33.5 +/- 2.7 and 31.6 +/- 2.6 years, respectively. The severity of the depression was assessed using the 17-item Hamilton Depression Scale (mean: 23.2 +/- 1.5). None of the patients was under medication. After administration of 500 MBq technetium-99m hexamethylpropylene amine oxime, a single photon emission tomography study was performed and then transaxial, sagittal and coronal slices were obtained. For the semiquantitative analysis of the data, the ratios of the mean counts/pixel to the whole slice were calculated for 24 regions on three consecutive transaxial slices in the orbitomeatal plane. Additionally, left/right and frontal/occipital ratios were calculated. Both sides of the temporal region had a significantly decreased cerebral blood flow (CBF) when compared to the controls. The left/right ratio of the prefrontal region was also significantly lower in the patients than in the controls. The Hamilton score had a negative correlation with blood flow in the anterofrontal and left prefrontal regions. According to our results, regional CBF seems to be decreased in the left prefrontal and in both temporal regions in major depression. The severity of depression is correlated with the reduction in CBF in the regions of the anterofrontal and left prefrontal cortex.

Adult↗
PubMed1992

Dual radioisotopic study: a technique for the evaluation of vasculogenic impotence.

Arterial and venous systems are the main points for the evaluation of vasculogenic impotence. To evaluate both of these systems in the same study we propose a dual radioisotopic study in which 99mtechnetium (99mTc) and 133xenon (133Xe) were used. The changes in 99mTc and 133Xe radioactivities administered intravenously and intracavernously, respectively, were monitored before and after intracavernous papaverine injection. These changes were determined as time activity curves, which were generated from the region of interest over the penis. A 99mTc penogram index derived from the 99mTc time activity curve was significantly different in the control and arteriogenic impotence groups (131.67 +/- 74.6 versus 62.94 +/- 51.6, p less than 0.01). A meaningful correlation between 99mTc penogram index results and duplex ultrasonographic findings were observed (r = 0.905). 133Xe penogram index, derived from the 133Xe washout curve was significantly different in the control and venogenic impotence groups (-25.65 +/- 24.9 versus -56.09 +/- 13.4, p less than 0.01). Also, a meaningful correlation was obtained between pharmacocavernosometry and 133Xe penogram index results of venogenic impotent patients (r = 0.86). These findings suggest that the dual radioisotopic study will be a useful technique in the evaluation of the entire vascular system of the penis, since it is a noninvasive method.

Adult↗
PubMed1992

Regional cerebral blood flow changes in chronic alcoholism using Tc-99m HMPAO SPECT. Comparison with CT parameters.

Twenty-eight patients were studied for regional cerebral blood flow changes as a result of chronic alcoholism. After the administration of 550 to 600 MBq Tc-99m HMPAO, tomographic slices were obtained using a SPECT camera. Eight regions per hemisphere were drawn on each transaxial section, and tracer redistribution was calculated for each region. Region-to-whole slice ratios were determined for each patient. Patients had significantly decreased frontal/whole slice (1 +/- 0.02) ratios in comparison with a normal group (p less than 0.01). Twenty-four out of 26 patients (85.7%) demonstrated abnormal rCBF. Eighteen out of 28 (64.3%) showed activity lower in the left hemisphere than in the right. Using CT parameters, 60% of the patients had either sulcal widening and/or ventricular enlargement. The frontal region and the left hemisphere were more affected by alcohol than other regions. More cerebral blood flow changes than morphologic changes were found caused by alcoholism.

Adult↗
PubMed1992

Assessment of left ventricular dysfunction in acromegalic patients using radionuclide ventriculography parameters.

The left ventricular function of 14 acromegalic patients was investigated using radionuclide ventriculography. After labeling the red blood cells with 750-1,000 MBq 99mTc-pertechnetate, ECG-triggered left anterior oblique images were recorded. Fourier analysis was then performed on the time-activity curve of the left ventricle. The ejection fraction (EF), peak ejection rate, time to peak ejection (TPE), time to end-systole (TES), peak filling rate (PFR), time to peak filling (TPF), 1/3 EF, 1/3 filling fraction (FF), TPE/T, TPF/T and TES/T values (T: time interval for one heart beat) were calculated for each patient. Five patients (35.7%) had clinical cardiovascular symptoms. A decreased EF was observed in 28.5% of the patients. In comparison to the control group, the EF (53.5 +/- 5.5 vs. 60.8 +/- 5% p less than 0.009), 1/3 EF (14.45 +/- 3 vs. 20 +/- 4%, p less than 0.001), 1/3 FF (28.5 +/- 10.6 vs. 41 +/- 11%, p less than 0.02), TPE (158 +/- 33 vs. 132 +/- 35 ms, p less than 0.01), TPE/T (20.2 +/- 5 vs. 16 +/- 3.7, p less than 0.01) and PFR (2.4 +/- 0.5 vs. 2.9 +/- 0.4 EDC/s, p less than 0.005) were significantly different. It was found that TPE was prolonged and the early ejection function was decreased. Diastolic dysfunction was found in 5 (35.7%) patients; 21.4% of the patients had decreased PFR values although they had no cardiac symptom, hypertension and/or cardiomegaly. Scintigraphic parameters did not correlate with the presence of hypertension, cardiomegaly or cardiovascular symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed1992

Scintigraphic evaluation of left ventricular function and correlation with autonomic cardiac neuropathy in diabetic patients.

Left ventricular function of 20 diabetic patients was investigated at rest and during hand-grip test using radionuclide ventriculography. The aim of the study was to discuss the correlation of cardiac function with autonomic cardiac neuropathy (ACN) in diabetic subjects. ACN was tested using heart rate response to valsalva maneuver, standing up, deep breathing; blood pressure response to standing up, sustained hand-grip, and additionally corrected QT (QTc) measurements. Plasma glucose regulation was screened with fructosamine levels. Ejection fraction (EF), peak ejection (PER) and filling rates (PFR), times to peak ejection (TPE) and filling (TPF), time to endsystole (TES), TES/T, TPE/T, TPF/T, 1/3 PER, 1/3 PFR, 1/3 EF, 1/3 FF (filling fraction) we calculated. Thirteen patients had ACN. Six patients (30%) had a low EF at rest. As a response to hand-grip, 14 patients (70%) showed a decrease in EF (9 ACN). PFR was low in 10 patients (50%) at rest and in 12 (60%) during hand-grip. The mean rest PER value of ACN+ patients (4.4 +/- 1.3) was significantly higher than that of controls (2.9 +/- 0.5) and patients without ACN (3.4 +/- 0.4; p < 0.05) as well as the mean 1/3 PER value (1.7 +/- 0.5 vs. 1.3 +/- 0.5; p < 0.05). Fourteen patients (70%) had a fall in PER 10 ACN) as a response to hand-grip. The mean TES/T value of patients with ACN (0.44 +/- 0.05) was significantly higher than of those without ACN (0.38 +/- 0.05; p < 0.05). In conclusion, diastolic dysfunction was detected frequently at rest. Systolic parameters were markedly impaired as a response to hand-grip in patients with ACN. Sympathetic overactivity was noted in ACN+ group at rest. Our results indicated that the patients with diabetes and ACN have subclinical left ventricular diastolic dysfunction and symphatic overactivity.

Adult↗
PubMed1991

Brain death: determination with brain stem evoked potentials and radionuclide isotope studies.

Thirty-three patients fulfilling the clinical criteria for brain death were tested by Brainstem Auditory Evoked Potentials (BAEP) and Radionuclide Cerebral Angiography and Brain Perfusion Studies. There was a significant correlation between the BAEP and radionuclide study outcomes. All patients with absence of BAEP showed no cerebral perfusion. These findings, added to the clinical findings, resulted in a final diagnosis of brain death in all patients. It is concluded that BAEP and Radionuclide Cerebral Perfusion studies are useful adjuncts for proving that brain death has really occurred.

Adolescent↗