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Biomedical subjects

S Aytaç

Publications and source records attributed to S Aytaç.

At least 19 recordsLinked to original sources
PubMed2002

Effect of submaximal and incremental upper extremity exercise on platelet function and the role of blood shear stress.

INTRODUCTION: Platelets are involved in the pathogenesis of atherosclerosis. Although physical exercise is recommended to prevent atherosclerosis, the effect of exercise on platelet function and the underlying mechanisms of these effects are not completely understood. Accordingly, we aimed to examine the effect of different intensities acute arm exercises on platelet function. In addition, we evaluated the effect of lipid peroxidation and fluid shear rate on platelet response. MATERIALS AND METHODS: Twenty four healthy sedentary male volunteers aged 18-24 years performed submaximal and incremental exercises by upper extremity ergometer. The shear rate in the right artery was measured by Power Doppler Ultrasound (US) at rest and immediately after exercise. Pre and postexercise maximum intensities of ADP and collagen-induced platelet aggregation were measured using the impedance technique. Bioluminescent detection of thrombin-induced platelet ATP release and measurement of thromboxane B(2) (TxB(2)) levels (as a marker of thromboxane A(2) (TxA(2)) formation) by enzyme-linked immunoassay were performed before and after exercise. RESULTS AND CONCLUSION: Shear rate increased after both submaximal and incremental exercise. Collagen-induced platelet aggregation increased after submaximal exercise, while ADP-induced aggregation and thromboxane B(2) levels did not alter with this protocol. Incremental exercise caused increased collagen and ADP-induced platelet aggregation and thromboxane B(2) levels. Neither of the protocols altered platelet ATP release. It was shown that acute upper extremity exercise increased platelet aggregation, without an increase in platelet release. Collagen-induced signalling pathways were more sensitive than those induced by ADP. The increase in thromboxane B(2) after incremental exercise implied increase in thromboxane A(2) formation and lipid peroxidation. Despite a significant correlation between platelet aggregation and thromboxane B(2) levels at rest, we found no clear-cut relationship between thromboxane A(2) formation, blood shear rate and platelet response to exercise.

Adenosine Diphosphate↗
PubMed1999

Multimodality demonstration of primary splenic angiosarcoma.

Angiosarcomas are rare, accounting for only 1-2% of all soft tissue sarcomas. Primary abdominal angiosarcomas usually arise in the liver or spleen. We report the first color Doppler findings of a rare, low-grade splenic angiosarcoma in a 52-year-old woman.

Female↗
PubMed1999

Effect of transurethral electrovaporization of the prostate on serum prostate specific antigen concentration.

OBJECTIVE: To assess the effect of transurethral electrovaporization of the prostate (TUVP) on serum prostate specific antigen (PSA) concentration. PATIENTS AND METHODS: Twenty-five men (mean age 61.7 years) with symptoms of prostatism underwent TUVP. Serum PSA levels were determined before any prostatic manipulation, and again at 1 and 24 h after TUVP. In the first 6 weeks after TUVP, serum PSA was measured every week. Prostatic size was measured by transrectal ultrasonography before and again at 6 weeks after TUVP. RESULTS: The mean serum PSA concentration was significantly higher at 1 and 24 h after TUVP (P<0.001) than before. The PSA level returned to less than the value before TUVP at 2, 3 and 4 weeks afterwards in eight (32%), 13 (52%) and 20 (80%) patients, respectively; five (20%) patients reached the baseline value 6 weeks after TUVP. The mean reduction in prostatic volume 6 weeks after TUVP was 42% and the reduction in tissue volume was significantly correlated with the decrease in serum PSA concentration at 6 weeks (P<0.05). CONCLUSION: TUVP increases serum PSA levels, the transient elevation persisting for up to 6 weeks but then declining to a stable, low PSA concentration. Therefore, it is important to wait at least 6 weeks to obtain an accurate and meaningful serum PSA level after TUVP.

Biomarkers↗
PubMed1998

A prospective randomized study of transurethral resection of the prostate and transurethral vaporization of the prostate as a therapeutic alternative in the management of men with BPH.

OBJECTIVE: The common goals of new surgical treatment for benign prostatic hyperplasia (BPH) are to improve subjective and objective symptoms, to decrease the risk of postoperative complications and short hospitalization. Transurethral electrovaporization of the prostate (TUVP) is a new, minimally invasive and a promising alternative to standard transurethral resection of the prostate (TURP) in the treatment of BPH. The aim of this study is to compare the efficacy and safety of these two treatment alternatives. METHODS: A prospective randomized trial of 60 patients with symptomatic BPH was performed. Preoperative and postoperative International Prostate Symptom Score (IPSS), maximum flow rates (Qmax) and complications were recorded in each patient. The volume of the prostate was measured preoperatively and postoperatively using transrectal ultrasound. RESULTS: Of the 30 patients who underwent TURP, mean hospital stay was 4.5 days. The Foley catheter was removed on postoperative day 4 following surgery. IPSS decreased from 21.6 to 5.2, Qmax increased from 9.2 to 19.2 ml/s at 3 months. Mean prostatic volume at 3 months decreased from 51.7 to 26.2 g, a 49.3% reduction. Of 30 patients undergoing TUVP, mean hospital stay was 2.5 days and the catheter was removed within 2 days following surgery. Postoperative urinary retention did not occur in any patient. IPSS decreased from 19.4 to 4.1 and Qmax increased from 7.9 to 17.7 ml/s at 3 months. Mean prostatic volume decreased from 48.9 to 27.8 g, a 43.1% reduction at 3 months. In the TUVP group, none of the patients required blood transfusions or developed clinical transurethral resection syndrome. There were no major complications. Sphincteric incontinence, urethral strictures or bladder neck contractures were not recorded. At 3 months postoperatively, 13 patients in the TURP group and 7 patients in the TUVP group had retrograde ejaculation. CONCLUSION: Our initial experience of TUVP suggests advantages over conventional TURP through reduced blood loss and shorter hospital stay. It appears to be an effective treatment for BPH; however, long-term results should be evaluated.

Electrosurgery↗
PubMed1997

Abscess formation due to dropped gallstone after laparoscopic cholecystectomy.

Laparoscopic cholecystectomy is a popular treatment modality of symptomatic gallstones with decreased major complications and shortened hospital stay. Complications following laparoscopic cholecystectomy, most of them involving strictures of biliary tract have been well described in recent reports. However, there are only a few reported cases about dropped gallstones after the procedure, all of which were opaque and easily demonstrated with multiple imaging modalities. An unusual complication of laparoscopic cholecystectomy; abscess formation due to a dropped non-opaque gallstone is described in which diagnosis was suggested with the combination of ultrasound and computed tomography findings and confirmed by surgery.

Abdominal Abscess↗
PubMed1997

Pseudotumour due to surgical sponge: gossypiboma.

The plain-film, ultrasonography and computed tomography findings of retained surgical sponges (gossypibomas) are described in three patients. When a mass with hyperechoic wavy structures and posterior acoustic shadowing is seen on ultrasonography, the history of previous surgery must be questioned. Gossypiboma should be included in the differential diagnosis of such cases with a previous surgery. Plain film and computed tomography examinations should be obtained for correct pre-operative diagnosis.

Adult↗
PubMed1995

Retroperitoneal fibrosis: evaluation by ultrasonography and color Doppler imaging.

Delay in diagnosis is common in retroperitoneal fibrosis because of the non-specific clinical presentation. Ultrasonography combined with color Doppler imaging is a rapid and practical method in the early diagnosis and during follow-up. We describe 3 cases with retroperitoneal fibrosis, emphasizing the ultrasonographic and color Doppler features of the disease.

Female↗
PubMed1994

Umbilical artery blood flow characteristics in normal pregnancies.

585 pregnant women were investigated with both conventional sonographic examination and color Doppler examination. The cases with intrauterine growth retardation, preeclampsia, twin pregnancies, congenital malformations and diabetes were excluded. The remaining 550 cases (between ages 16 and 40) were investigated in the first trimester and gestational ages were compatible with the last menstrual date. In order to evaluate fetal development, biparietal diameter, femur length, abdominal circumference, and estimated fetal weight were calculated by conventional ultrasonographic method. The application of Doppler ultrasound to the study of fetal umbilical arterial blood flow velocity is a relatively new technique. The failure to obtain useful Doppler signals was about 18-22% with pulse-wave Doppler system. Recently, color Doppler technology solved this problem. We used an ALOKA 680-SSD ultrasonography device and color Doppler ultrasonography technique and recorded umbilical arterial Doppler signals from every case and calculated classical Doppler indices--systolic/diastolic (S/D) ratio, pulsatility index (PI), Pourcelot index or resistive index (RI). Statistical comparisons were made by SPSS program. Correlation coefficient and R2 values between gestational age and other indices were calculated. The aforementioned values were r:-0.79; R2:0.63 0.63; r:-0.71; R2:0.50, r:-0.64; R2:0.41, for S/D, PI, RI, respectively.

Adolescent↗
PubMed1994

Multidisciplinary evaluation of diabetic impotence.

Patients referring to the Urology and/or Endocrinology Departments of Ankara Medical School with complaints of diabetes mellitus (DM) and related complications were evaluated during the last year. A detailed history was obtained and all of the patients were questioned especially about sexual function problems. Following this evaluation, all patients were divided into two main groups, i.e. patients with sexual disorders, and those with normal sexual function. Factors such as BPH, cerebrosclerosis and other important vascular-neurologic pathologies which may play a role in the etiology of impotence were excluded from the study and 38 patients with sexual dysfunction and 15 with normal sexual activities have undergone further evaluation. Following routine blood and urine analyses, serum hormone levels (testosterone, FSH, LH, prolactin) were determined. Penile color-flow doppler analysis, cavernosometry, cavernosography, bulbocavernous reflex latency time and evaluation of somatosensory evoked potentials were performed. Additionally, all patients were evaluated from the psychiatric aspect using the Hamilton depression scale and MMPI questionnaire. The presence of vascular or neurologic pathology in 89.4% of our patients and of both pathologies in 39.4% of the patients, indicated the importance of multifactorial evaluation of diabetic impotence in order to plan a complete and efficient therapy program.

Adult↗
PubMed1993

Characterisation of renal masses with colour flow Doppler ultrasonography.

Colour flow Doppler ultrasonography (US) was used in 24 renal masses (12 benign, 12 malignant) to investigate the vascularity of the lesion and thus to characterise the mass. A colour flow Doppler US device (Toshiba 270 A) with a convex probe of 3.75 MHz was used. Colour flow and the peak-systolic Doppler shift frequency obtained from the renal mass were used to distinguish between benign and malignant lesions. Ten of 12 malignant lesions demonstrated colour flow together with Doppler signals greater than 2.5 kHz (mean 3.5 kHz). None of the 12 benign renal masses demonstrated colour flow or tumour signals. The majority of malignant lesions give rise to neovascularisation and so high frequency Doppler-shifted signals. Thus colour flow Doppler sonography is the most reliable means of differentiating benign from malignant renal masses.

Adult↗
PubMed1991

Multiparametric evaluation of testicular atrophy due to varicocele.

63 men with palpable left varicoceles were evaluated by semen analysis, scrotal ultrasonography, Doppler sonography, scrotal contact thermography, and radionuclide scanning. 11 (17.4%) patients had bilateral varicoceles detected by scrotal ultrasonography as compared with an incidence of 3.1% by scrotal palpation. Testicular atrophy was found in 29 (46%) patients by scrotal ultrasonography. This was found to be 39.6% by scrotal palpation alone. In this study using advanced diagnostic procedures, the incidences of bilateral varicocele and testicular atrophy due to varicocele were found to be much higher than when scrotal palpation alone was performed.

Adolescent↗
PubMed1991

Sialographic and ultrasonographic analyses of major salivary glands.

Seventy patients with major salivary gland diseases (60 parotis, 10 submandibular) were examined both with sialography and ultrasonography. The clinical and histopathological results were compared with radiological interpretations. Sialography was found to be 60% accurate for the diagnosis of salivary gland tumors and cysts and 63% for the diagnosis of inflammatory diseases. Ultrasonography diagnosed 95% of the tumors and 63% of inflammatory diseases accurately.

Adolescent↗
PubMed1980

A case of Whipple's disease complicated by fatal hepatitis.

Whipple's disease was diagnosed in a 42-year-old woman by the histological examination of a mesenteric lymph node taken at laparotomy, and the electron microscopic examination of a peroral intestinal biopsy specimen. She responded well to tetracycline therapy, but succumbed to fatal hepatitis ten weeks after the diagnosis of Whipple's disease

Adult↗