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Biomedical subjects

Biray Caner

Publications and source records attributed to Biray Caner.

10 recordsLinked to original sources
PubMed2005

Losartan renography for the detection of renal artery stenosis: comparison with captopril renography and evaluation of dose and timing.

PURPOSE: Radionuclide renography with angiotensin converting enzyme (ACE) inhibition plays an important role in the diagnosis of haemodynamically significant renal artery stenosis. Angiotensin receptor antagonists inhibit the renin angiotensin system at different levels from ACE inhibitors by selectively blocking the binding of angiotensin II to AT1 receptors. The AT1 angiotensin receptor antagonist losartan has recently been used clinically in the treatment of hypertension. However, the available data on the use of losartan with renography for the detection of renovascular hypertension are limited and contradictory. The purpose of this prospective study was to compare the effectiveness of losartan renography and captopril scintigraphy in revealing renal artery stenosis. METHODS: A total of 61 renal units in 32 patients with hypertension were studied in two groups based on the losartan dosage (50 mg in group A and 100 mg in group B). Group A consisted of 17 patients, in whom 19 renal units had angiographically proven renal artery stenosis (>or=50%). In group B, there were 15 patients, in whom 20 renal arteries were stenotic. All of the patients underwent three renographies (baseline, captopril renography and early losartan renography). Early losartan renography was performed at 1 h after oral losartan administration in both groups. In group B, seven patients underwent additional losartan renography (late losartan) performed 3 h after oral losartan administration; these patients composed group B1. RESULTS: The sensitivities of captopril and losartan studies were 63.2% and 42% in group A, 65% and 65% in group B and 55.6% and 66.6% in group B1, respectively. CONCLUSION: From our preliminary results, we conclude that losartan is not superior to captopril renography for the detection of haemodynamically significant renal artery stenosis. However, a high dose (100 mg) of losartan provided higher sensitivity than the lower dose (50 mg). Late losartan scintigraphy provided similar diagnostic efficacy to early losartan renography.

Adolescent↗
PubMed2004

Prospective study of combined modality treatment or radiotherapy alone in the management of early-stage adult Hodgkin's disease.

PURPOSE: To determine the efficacy and toxicity of combined modality treatment (CMT) or radiotherapy (RT) alone in the management of clinical Stage I-IIA adult Hodgkin's disease patients. METHODS AND MATERIALS: Forty-seven patients with supradiaphragmatic clinical Stage I-IIA Hodgkin's disease without bulky mediastinal lymphadenopathy were enrolled into this prospective study between September 1997 and February 2002. Patients with very favorable criteria presenting with one or two nonbulky nodal areas involved, an erythrocyte sedimentation rate of <50 mm/h, age <40 years, and either lymphocyte predominant or nodular sclerosing histologic findings were treated by RT alone. Patients missing any of these favorable criteria were classified as the other favorable group and were treated with three courses of doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy followed by involved-field RT. The median age was 36 years (range, 19-53 years). Of the 47 patients, 15 were women and 32 were men. Only 3 patients were classified as the most favorable group and treated with mantle RT alone; the remaining 44 were treated with CMT. RESULTS: The median follow-up was 51 months (range, 20-74 months). Only 2 patients developed recurrence, both out of the irradiated field, one in the contralateral neck and the other in the abdomen. The 5-year relapse-free and overall survival rate was 95.4% and 97.8%, respectively. Although none of the prognostic factors were statistically significant for relapse-free survival, a trend was noted for the response to chemotherapy (p = 0.06). Only 2 patients developed treatment-related complications. One patient treated with mantle RT alone developed severe ischemic heart disease and one in the CMT arm developed subclinical hypothyroidism. CONCLUSION: Despite the short follow-up, CMT or RT alone tailored according to the clinical prognostic factors were successful in terms of disease control in clinical Stage I-IIA Hodgkin's disease. Longer follow-up is required to make definitive conclusions.

Adult↗
PubMed2004

Lung hilar Ga-67 uptake in patients with lymphoma following chemotherapy.

Scintigraphic characteristics of lung hilar Ga-67 uptake (HU) and their relationship with the etiology (benign vs. malignant) of the hilar lesions in lymphoma patients following chemotherapy were retrospectively investigated. A total of 161 lymphoma patients were included in the study. The presence/absence of HU and if present, symmetry/asymmetry and intensity of HU (on the basis of a 3 scale grading system) were visually and semiquantitatively assessed on transaxial sections of thorax Ga-67 SPECT. By drawing ROIs over right and left hilum, asymmetry index (AI%) was also calculated. HU was categorized as benign or malignant depending on the radiological correlation and clinical follow-up. In the malignant group, the majority of patients (85.7%) had grade 2 or grade 3 uptake and all had asymmetric pattern. However, in the benign group, grade 1 uptake was more common (66%) and was mainly symmetric (94.6%) in appearance. AI% in the malignant group (73.7 +/- 36.6) was significantly higher than in the benign group (5.7 +/- 4.9) confirming the marked asymmetry in malignant patients.

Adolescent↗
PubMed2003

Stripe sign in pulmonary embolism: a review of the causes.

The most common indication for radionuclide imaging of lungs is the evaluation of suspected pulmonary thromboembolism (PE). Scintigraphically PE classically produces ventilation/perfusion mismatch, that is perfusion defects in areas showing normal ventilation. Stripe sign refers to the visualization a stripe at normally perfused lung interposed between a defect and adjacent pleural surfaces as originally described by Gottschalk. In the present case the authors describe a patient with a ventilation/perfusion scan suggesting PE. She also had a stripe sign on the perfusion scan with normal ventilation. On the follow-up perfusion scintigraphy, normal perfusion was seen in the corresponding area. The literature on stripe sign is also reviewed.

Diagnosis, Differential↗
PubMed2003

Increased intra-abdominal pressure results in both obstructive and nonobstructive types of impairments of renal pelvic excretion.

UNLABELLED: An experimental study has been conducted to evaluate the effects of increased intra-abdominal pressure (IAP) on the excretion function from renal pelvis into the ureter. METHODS: Sixteen adult male New Zealand rabbits were randomly allocated in two groups after obtaining basal scintigraphies. Group I consisted of 8 rabbits which were subjected to an increased IAP for ten day period. In Group II an other 8 rabbits were subjected to an increased IAP for 60 day period. At the end of the periods of increased IAP the post-pressure scintigraphic evaluations of both groups were carried out. Time to maximum activity (Tmax), T1/2 and T2/3 values of the radiopharmaceutical in the kidneys and down slope parameters (DS1/2, DS2/3) were calculated from the renogram curves of both right and left kidneys. Comparison of basal and post-pressure scintigrapies and the mean difference of the renogram parameters between groups were performed. RESULTS: All basal scintigraphies were normal. Post-pressure scintigraphies revealed an obvious delay in the excretion phase in both groups. Both kidneys of a rabbit in group I revealed a non-obstructive pattern through responding well to administration of diuretic. Furthermore both kidneys of a rabbit from group II have revealed an obstructive pattern. T1/2 and T2/3 values were significantly elevated and mean DS1/2, DS2/3 were significantly decreased in post-pressure scintigraphies of the both groups without revealing a statistically significant difference between groups I and II. The mean difference of Tmax was significantly increased in group II. CONCLUSION: The increases in IAP, through the compressive effect upon ureters together with a concomitant increase in intravesical pressure, may impair the passage of urine from renal pelvis into ureter. The impaired passage may play a role in the development of hydronephrosis which may either reveal a nonobstructive and/or obstructive pattern.

Abdomen↗
PubMed2003

Biological reactions to a poly(L-lactide)-hydroxyapatite composite: a study in canine mandible.

In this study, bone response, possible use and ultimate fate of a chemically-synthesized poly(L-lactide)-hydroxyapatite (PLLA-HA) composite was experimented in canine mandible. Bilateral mandibular second premolars were extracted in four dogs. The PLLA-HA composite was placed into left surgical sites, and right extraction sites were used as controls. After three months of healing, bone specimens were harvested from each animal and processed for histological evaluation. Bone uptake of methylene diphosphonate (99mTc-MDP) was calculated as indicators of osteoblastic activity in the surgical sites. Histological evaluation and the amount of 99mTc-MDP uptake showed that all surgical sites had similar levels of cellular activity and the material was biocompatible. The experimental PLLA-HA composite studied is safe to be used as a small-defect filler in applications such as repair of alveolar defects, ridge augmentations, and sinus lift procedures.

Animals↗
PubMed2002

Bone SPECT imaging of patients with internal derangement of temporomandibular joint before and after splint therapy.

OBJECTIVE: Temporomandibular joint (TMJ) patients with disc displacement without reduction have a misaligned disc-condyle structural relation. As the condition becomes chronic, painful osteoarthritic changes may occur. For these patients, splint therapy may help to position the condyle to a more structurally compatible and functional position and to decrease the loading force of articular surfaces. The aim of this study was (1). to evaluate osseous reactions and pain relief in patients with disc displacement without reduction after splint therapy and (2). to use single photon emission tomography (SPECT) bone imaging to compare the results with the opposite joint of the patient. STUDY DESIGN: Twelve patients, who presented with pain involving the TMJ and limited mouth opening and were confirmed by soft tissue imaging as having disc displacement without reduction, were included in the study. Each patient underwent bone SPECT imaging, after which semiquantitative evaluation of transaxial images was conducted. The ratios of affected TMJ to nonaffected TMJ, affected TMJ to occipital bone, and nonaffected TMJ to occipital bone were calculated. After 6 months of splint therapy, bone SPECT examinations were repeated. RESULTS: Before splint therapy, the ratios of affected TMJ to nonaffected TMJ and of affected TMJ to occipital bone were found to be significantly higher than the ratios after splint therapy (P < 0.005). CONCLUSION: Six-month splint therapy has a positive effect on the osseous reaction and pain related to internal derangements of TMJs.

Adolescent↗
PubMedDate not supplied

Thrombus localization by using streptokinase containing vesicular systems.

Our research focused on the preparation of vesicular drug delivery systems, such as liposomes, noisomes, and sphingosomes, for achieving slow release of entrapped proteins in the circulation to increase half-life, to mask immunogenic properties, and to protect against loss of enzymatic activity. We prepared, characterized, and monitored the biodistribution of three types of vesicular systems (liposomes, niosomes, and sphingosomes) containing streptokinase. For biodistribution stuides, radiolabelled streptokinase dispersions were injected into the ear vein of female rabbits in the weight of 2.5-3 kg weight. Following the application, rabbits were sacrificed, then organs of these animals were removed and radioactivity of organs was measured by well-type gamma counter. The comparison of the biodistribution results of the free streptokinase with the streptokinase vesicles showed that incorporation of the enzyme into the vesicles changed the biodistribution of the drug and by the entrapment of the streptokinase in the vesicles, thrombus uptake and imaging quality were improved.

Animals↗