Arif Kursad Ayan

The role of carnitine on ovariectomy and inflammation-induced osteoporosis in rats

This study was carried out to assess the protective bone-sparing effect of carnitine with anti-inflammatory properties on chronic inflammation-induced bone loss in ovariectomised (OVX) rats. A total of 64 rats were divided into eight groups. Sixteen rats were sham-operated (SH) while the others were ovariectomised (OVX). (1) SH, (2) sham + inflammation (SHinf), (3) OVX, (4) ovariectomy + inflammation (OVXinf), (5) OVX + CAR1, (6) OVX + CAR2, (7) OVXinf + CAR1, (8) OVXinf + CAR2. After the ovariectomy surgery, all the groups (3, 4, 5, 6, 7, and 8) were allowed to recover for two months. Sixty days after the OVX, inflammation was induced by subcutaneous injections of talc in groups 2, 4, 7, and 8. Group 5 and 7 were given 50 mg/kg CAR; Group 6 and 8 were given 100 mg/kg CAR from the 60th to the 80th day. Serum levels of TNF-α, IL-1, IL-6, OP, and OC were assessed to determine inflammation and to evaluate osteoblastic activity. Bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry in femur bones of rats. Carnitine administration was able to restore BMD up to values measured in both the OVX and the SH animals. The serum levels of TNF-α, IL-1β, and IL-6 were increased significantly in the OVXinf rats compared with the SH group. In OVX rats, inflammation which is evaluated by serum cytokine levels exacerbated this bone loss, as supported by values of BMD of the total femur. The two different doses of carnitine reduced bone loss and improved inflammatory biomarkers.

Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

INTRODUCTION Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN). METHODS The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period. RESULTS In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05). CONCLUSIONS This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

Treatment with Carnitine Enhances Bone Fracture Healing under Osteoporotic and/or Inflammatory Conditions

The aim of this study was to examine the effects of carnitine on bone healing in ovariectomy (OVX) and inflammation (INF)‐induced osteoporotic rats. The rats were randomly divided into nine groups (n = 8 animals per group): sham‐operated (Group 1: SHAM); sham + magnesium silicate (Mg‐silicate) (Group 2: SHAM + INF); ovariectomy (Group 3: OVX); ovariectomy + femoral fracture (Group 4: OVX + FRC); ovariectomy + femoral fracture + Mg‐silicate (Group 5: OVX + FRC + INF); ovariectomy + femoral fracture + carnitine 50 mg/kg (Group 6: OVX + FRC + CAR50); ovariectomy + femoral fracture + carnitine 100 mg/kg (Group 7: OVX + FRC + CAR100); ovariectomy + femoral fracture + Mg‐silicate + carnitine 50 mg/kg (Group 8: OVX + FRC + INF + CAR50); and ovariectomy + femoral fracture + Mg‐silicate + carnitine 100 mg/kg (Group 9: OVX + FRC + INF + CAR100). Eight weeks after OVX, which allowed for osteoporosis to develop, INF was induced with subcutaneous Mg‐silicate. On day 80, all of the rats in groups 4–9 underwent fracture operation on the right femur. Bone mineral density (BMD) showed statistically significant improvements in the treatment groups. The serum markers of bone turnover (osteocalcin and osteopontin) and pro‐inflammatory cytokines (tumour necrosis factor α, interleukin 1β and interleukin 6) were decreased in the treatment group. The X‐ray images showed significantly increased callus formation and fracture healing in the groups treated with carnitine. The present results show that in a rat model with osteoporosis induced by ovariectomy and Mg‐silicate, treatment with carnitine improves the healing of femur fractures.

Evaluation of bone metastasis as the first presentation of hepatocellular carcinoma using 18-fluorodeoxyglucose positron emission tomography-computed tomography.

We report a case of a patient with hepatocellular carcinoma (HCC) who presented with back pain related to bone metastasis. HCC metastasizes by hematogenous and lymphatic routes commonly to the lungs, regional lymph nodes, kidney, bone marrow and adrenals. In this extremely rare case, the patient had no known liver disease, but presented with liver lesions and multiple bone lesions involving vertebrae, ribs, pelvic bones and left femur with associated expansile soft-tissue components. These bone lesions were first detected from a positron emission tomography scan. Pathological examination of biopsy material taken from the left eighth rib confirmed metastatic HCC. In conclusion, if a patient has expansile osteolytic bone lesions, bone metastasis from HCC should be included in the differential diagnosis.

Investigation of inhibition of human glucose 6-phosphate dehydrogenase by some 99mTc chelators by in silico and in vitro methods

Abstract The inhibitory effects of methoxyisobutylisonitrile (MIBI), diethylene triamine pentaacetic acid (DTPA), dimercaptosuccinic acid (DMSA) and metilendifosfonat (MDP) on human erythrocyte glucose 6-phosphate dehydrogenase (hG6PD) activity were investigated. For this purpose, hG6PD was initially purified 557-fold at a yield of 51.43% using 2′,5′-adenosine diphosphate (ADP) sepharose 4B affinity gel chromatography. The in vitro effects of these chelators on hG6PD enzyme were studied. IC50 values of MIBI, DTPA, DMSA and MDP were 0.056, 0.172, 0.274 and 0.175 mM, of hG6PD, respectively. It was detected in in vitro studies that the hG6PD enzyme is inhibited due to these radiopharmaceutical chelators. In addition to in vitro studies, in order to better understand the molecular mechanism of studied compounds, combined in silico approaches, including molecular docking and molecular dynamics (MD), simulations were successfully performed. MD simulations shed light on inhibition mechanisms of the individual inhibitors into the ligand-binding pocket of hG6PD. Essential amino acids for binding are also investigated using per-residue interaction analysis studies.

The Importance of FDG-PET/CT in Cogan’s Syndrome

The present study gives a detailed report of a patient with atypical Cogan’s syndrome with uveitis and sensorineural hearing loss. Cogan’s syndrome is characterized by nonsyphilitic interstitial keratitis and audiovestibular dysfunction. This syndrome can be divided into two groups, typical and atypical, based on the presence of interstitial keratitis. It may sometimes be associated with systemic vasculitis. Fluoro-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) scanning was used to investigate the presence of vasculitis. With FDG-PET/CT scanning, there is no pathological involvement in the walls of the arteries; thus the patient is protected from aggressive and long term immunosuppressive treatment’s side effects. Hence, we can conclude that FDG-PET/CT may play an important role in excluding the presence of vasculitis.

Evaluation of salivary gland function in allergic rhinitis patients by [99mTc] pertechnetate salivary gland scintigraphy

The purpose of this study was to compare the quantitative parameters of salivary gland functions in patients with allergic rhinitis and healthy volunteers using [99mTc] pertechnetate salivary gland scintigraphy. Thirty-six patients with allergic rhinitis (14 males and 22 females, mean age 30.6 ± 5.2 years) and thirty-nine healthy controls (18 males and 21 females, mean age 32.2 ± 5.6 years) were evaluated. Dynamic salivary gland scintigraphy was performed after intravenous administration of 185 MBq (5 mCi) of [99mTc] pertechnetate for 25 minutes. Lemon juice was used to stimulate the salivary glands. On the basis of the time-activity curves, the following glandular function parameters were calculated for the parotid and submandibular salivary glands: uptake ratio, maximum accumulation, and ejection fraction. Statistically, all the functional parameters of the parotid and submandibular glands obtained for the allergic rhinitis patients were significantly lower than those of the healthy controls group (p < 0.05). This study demonstrated that there was a significant difference in salivary gland function between patients with allergic rhinitis and healthy controls, which can easily be evaluated by [99mTc] pertechnetate salivary gland scintigraphy.

Vesicoureteral reflux in a nonfunctioning kidney detected by 99mTc-DTPA study

Vesicoureteral reflux (VUR) is a well-recognized condition in the pediatric population, but is less well described in the adult population, and its prevalence decreases with increasing age. We describe the case of a 53-year-old male with nonfunctional kidney in which accumulation of radioactivity was observed in the ureter and renal pelvis owing to VUR, which was detected by technetium-99m diethylenetriamine pentaacetic acid dynamic renal scintigraphy.