Scintigraphic evaluation of graft and native liver function after heterotopic liver transplantation.
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Biopsy, Needle↗
Biomedical subjects
A Aktaş
Publications and source records attributed to A Aktaş.
Impact of radiotherapy on normal brain tissue: semi-automated quantification of decrease in perfusion.
PURPOSE: We attempted to ascertain the impact of Co-60 conventional external radiotherapy (cRT) on the perfusion of normal brain tissue in relation to the radiation doses delivered to the tumors in patients with primary brain tumors. MATERIALS AND METHODS: After surgery 18 patients (pts) were due to undergo cRT with a total dose of 5400- 6400 cGy. All the patients had a Tc-99m-HMPAO SPECT study prior to cRT (basal), 15th and 30th days of cRT as well as 1 (in 6 pts), 3 (in 9 pts), and 6 (in 3 pts) months after cRT. For quantitative evaluation, the entire set of transverse slices were divided into 4 regions as frontal, parietal, occipital and temporal regions by means of a computer software program. Semi-automated quantification was performed on a total of 1392 regions in 87 studies to determine left to right ratios. An interregional difference of at least 10% was considered abnormal. RESULTS: After elimination of tumor sites, 80 normal brain regions showed decreased perfusion after cRT. The percent decrease in perfusion was (mean 22.5+/-9.9) significantly higher in areas irradiated with doses > 3000 cGy (p < 0.05). CONCLUSION: cRT has adverse effects on the perfusion of normal brain tissue for doses > 500 cGy. Our findings justify treating patients with small and limited lesions with stereotactic radiotherapy in order to minimize the adverse effects of cRT on normal tissues.
Adolescent↗
[Evaluation of nasolacrimal duct function in chronic paranasal sinus infections with 99mTc dacryoscintigraphy].
BACKGROUND: Paranasal sinus infections and nasolacrimal duct obstructions are commonly encountered problems. However the relationship between these two conditions is not yet clear. Trauma, surgery, tumors, and systemic diseases are among the causes of acquired nasolacrimal duct obstructions but most of the cases are idiopathic. In this study patients diagnosed with chronic paranasal sinus infection were examined with 99mTc lacrimal dacryoscintigraphy to assess their nasolacrimal duct function. METHODS: Twenty-four patients diagnosed with chronic paranasal sinus infection are included in the study. These patients were observed for at least three months awaiting surgical treatment following unsuccessful medical treatment. The control group included 16 persons admitted to the ophthalmology department without any nasolacrimal duct disease. Nasal endoscopy and paranasal sinus CT revealed normal findings. The age of the patients with chronic paranasal sinus infection and examined in regard to nasolacrimal duct function was between 15 to 17 with a mean age of 34.2 years. Fourteen patients were male and 10 patients were female. The control group included 9 male and 7 female patients between 18 to 60 years with a mean of 30.5 years. RESULTS: The dacryoscintigraphic examination of 48 nasolacrimal ducts in 24 patients with chronic paranasal sinus infection revealed 7 complete and 18 partial obstructions of the duct, and 23 normal findings. In the control group with 32 nasolacrimal ducts of 16 patients, there was no complete obstruction. Partial obstruction (10.6, 12.0, 14.7 minutes) was be observed in three cases. The statistical workup resulted in a significant difference between paranasal sinus patients and control group (x2 = 15,840 p < 0.001). The paranasal sinus CTs of the patients with paranasal sinus disease were staged using the Lund-Mackay staging system: There is no correlation between the staging score of the paranasal sinus infection and the degree of the obstruction the nasolacrimal duct. CONCLUSION: This study shows that chronic paranasal sinus disease plays an important role in the pathogenesis of nasolacrimal duct obstructions. The presence of infection has an influence on the nasolacrimal drainage system, but the distribution (staging) of the infection does not appear to correlate with the degree of nasolacrimal duct obstruction. Partial obstruction cases that may progress to complete obstruction may be detected by dacryoscintigraphy, and the treatment of chronic paranasal sinus disease may help to overcome the lacrimal drainage problems in these cases.
Adolescent↗
The relation between the degree of gastro-oesophageal reflux and the rate of gastric emptying.
In this study, we evaluated the relationship between the degree of gastro-oesophageal reflux and the rate of gastric emptying and determined the variability of gastric emptying in children. The reproducibility of radionuclide imaging for the presence and grading of gastro-oesophageal reflux was also examined. Twenty-eight children less than 2 years of age participated in the study. For assessment of variability, all subjects underwent two scintigraphic studies. For each study, the number of reflux episodes and gastric emptying half-times were recorded. The amount of reflux was graded according to the classification suggested by Blumhagen. Patients with grade 1 reflux were considered low-grade refluxers, while patients with grade 2 or 3 reflux were considered high-grade refluxers. The level of reflux for each patient was based on the highest reflux grade recorded in either study. Of the 28 patients, 19 had reflux in at least one study. Ten patients had high-grade and nine patients low-grade reflux. All patients but one with high-grade reflux had the same grade of reflux in both studies (90%). Of nine patients with low-grade reflux, three had the same grade in both studies. The mean half-time was significantly higher for high-grade than for low-grade refluxers (P < 0.05). For subjects with low-grade reflux, this value did not differ significantly from that of non-refluxers (P > 0.05). Our results show that patients with high-grade gastro-oesophageal reflux had prolonged gastric emptying. The inter- and intra-subject variability of gastric emptying in children appeared to be low. Reproducibility for the presence and grading of gastro-oesophageal reflux by the radionuclide method was good, with the highest value being for the diagnosis of high-grade gastro-oesophageal reflux.
Gastric Emptying↗
High frequency of sister chromatid exchanges in lymphocytes of the patients with Behçet's disease.
Behçet's disease (BD) (OMIM 109650) is an immunogenetically based multisystem disease, characterized by iridocyclitis, arthritis, orogenital ulcerations and pustular skin lesions. Viral and autoimmune etiologies have been suggested and HLA-B5 has been found to predominate in BD. The disease is most seen in Turkey and Japan. Although familial cases have been reported, the mode of inheritance is not clear. To determine the genetic instability in BD, sister chromatid exchange (SCE) analysis has been performed on peripheral lymphocytes in 23 patients and 20 healthy controls. We found significantly higher SCE rates in the patient group (p < 0.0001). Our results may indicate that genetic impairment and genetic instability may play an important part in the etiology of BD.
Adult↗
Brain dead donors for organ transplantation.
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Adult↗
Sensitivity of radionuclide imaging, Doppler, and gray-scale ultrasound to detect acute rejection episodes, based on the pathologic grade of acute rejection.
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Acute Disease↗
99Tcm-glutathione for imaging inflammatory lesions.
The purpose of this study was to demonstrate the accumulation of 99Tcm-glutathione (GSH) in experimental abscesses. The biodistribution of 99Tcm-GSH was determined in mice with turpentine-induced abscesses in comparison with 99Tcm-human immunoglobulin (HIG) at 1, 3, 6 and 24 h. Arthritis was induced by intra-articular injection of ovalbumin in the right front knees of 16 rabbits. Each radiopharmaceutical (RP) was administered intravenously to eight rabbits. Scintigrams were obtained and regions of interest (ROIs) over the involved and contralateral knees were compared. Blood clearance of both RPs was studied in 10 normal rabbits. Biodistribution studies indicated accumulation of 99Tcm-GSH in abscesses. Abscess to liver, muscle, intestine and blood ratios were higher at all time points compared to 99Tcm-HIG. The maximum abscess:muscle ratios were 7.57 +/- 0.73 and 5.98 +/- 1.17 at 24 h for 99Tcm-GSH and 99Tcm-HIG, respectively. Scintigraphic images demonstrated both the abscesses and arthritic joints very well. 99Tcm-GSH is superior to 99Tcm-HIG due to clearance predominantly via kidneys, no significant accumulation in any other organs, high target-to-nontarget ratios attained a few hours after administration, low cost and in-house preparation by a simple procedure.
Abscess↗
Accumulation of 99mTc-glutathione in head and neck tumors.
Glutathione labelled with 99mTc was used to study blood clearance and normal distribution in 3 healthy volunteers and in 10 patients with biopsy-proven tumors in the head and neck region. Static scintigrams were obtained at 1, 3, 6, and 24 h. ROIs over tumors and normal soft tissues were compared to obtain T/N ratios. In normal subjects blood clearance reached a plateau at 6 h; no radio-activity accumulation in the head and neck region was observed. Only the cardiac blood pool, the liver, the kidneys and the urinary bladder were evident. Excretion was via the kidneys. Malignant tumors and metastases were well visualized in 7 patients (true-positive), starting at 1 h. The mean T/N ratio was 2.69 +/- 0.77. The best images were obtained at 3-6 h. 1 false-positive (granulamatous reaction), 1 false-negative (malignant epithelial tumor in the radix of tongue) and 1 true-negative (angiofibroma) results were obtained. 99mTc-GSH is a potential radiopharmaceutical for the scintigraphic visualization of head and neck tumors. Further clinical studies are warranted to show its sensitivity and accuracy.
Adult↗
Serum E-selectin and beta 2-microglobulin levels in Behçet's disease.
Behçet's disease is a systemic vasculitis of unknown aetiology. Endothelial cell injury plays an important role in the pathogenesis and immunopathology of systemic vasculitises, but an immunopathogenic basis is also probable in Behçet's disease. E-selectin is an indicator of endothelial injury, and beta 2-microglobulin (beta 2M) is increased in immunological disorders. The serum concentrations of these two markers were determined in 40 patients with active Behçet's disease and 40 healthy controls. E-selectin was determined by enzyme-linked immunosorbent assay and beta 2M was determined by the nephelometric method. The mean (+/- SD) serum concentration of E-selectin was 122.13 +/- 62.32 ng/ml and that of beta 2M was 0.31 +/- 0.05 mg/dl. Both concentrations were statistically significantly increased in patients with Behçet's disease compared with controls. More comprehensive studies are needed to determine whether these parameters are useful indicators of the activity of Behçet's disease.
Adolescent↗