Ali Sahin

The effect of alpha-lipoic acid in ovariectomy and inflammation-mediated osteoporosis on the skeletal status of rat bone

Osteoporosis is a high mortality and morbidity ranged skeletal disease and results in high costs of medical care in the European Union. We evaluated the possible protective effect of alpha-lipoic acid (ALA) on rat bone metabolism in ovariectomy and inflammation-mediated osteoporosis models. Groups were designed as: (1) sham; (2) sham+inflammation; (3) ovariectomy (OVX); (4) ovariectomy+ALA-25mg/kg; (5) ovariectomy+ALA-50mg/kg; (6) ovariectomy+inflammation; (7) ovariectomy+inflammation+ALA-25mg/kg; and (8) ovariectomy+inflammation+ALA-50mg/kg groups. OVX groups were allowed to recover for two months. Then, inflammation was induced in inflammation groups by subcutaneous talc injection. ALA-25mg/kg and 50mg/kg were administered to drug groups chronically. The skeletal response was assessed by bone mineral density (BMD), osteopontin and osteocalcin measurements. Pro-inflammatory cytokine measurements (interleukin (IL)-1 beta, interleukin-6, and tumor necrosis factor-alpha) were performed to observe inflammatory process. In OVX, INF and OVX+INF groups, BMD levels were lowest and osteocalcin, osteopontin, IL-1 beta, IL-6, and TNF-alpha levels were highest when compared to sham group. ALA administration increased BMD levels and decreased osteocalcin, osteopontin, IL-1 beta, IL-6, and TNF-alpha levels versus OVX and OVX+INF control groups. Both in senile and postmenopausal osteoporosis, the balance in coupling were destroyed on behalf of bone resorption. ALA had a protective effect on both senile and postmenopausal osteoporosis. The positive effect of this drug in these osteoporosis models might originate from its positive effects on bone turnover markers and cytokine levels. From this perspective, ALA may be a candidate for radical osteoporosis treatment both in senile and postmenopausal types clinically at the end of advanced studies.

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.

The effects of vitamin E and selenium on blood flow to experimental skin burns in rats using the 133Xe clearance technique

The aim of the present experimental study was to determine and to compare the effects of vitamin E and of selenium on the blood flow to a wound region in rats, using the xenon-133 (133Xe) clearance technique. Burn wounds were made on the right thighs of rats followed by oral administration of vitamin E or selenium for a period of 10 days. The effect of vitamin E and of selenium individually on blood flow in the wound region was assessed before and after oral administration using the 133Xe clearance technique. Both vitamin E and selenium significantly increased the blood flow in the wound region (P<0.05). Our results in rats suggest that both vitamin E and selenium have beneficial effects on the skin wound healing process by increasing the skin blood flow.

On debonding of graded thermal barrier coatings

Thermal barrier coatings generally consist of a metallic substrate which is the primary structural component, a metallic bond coat which serves as oxygen diffusion barrier, a very thin layer of thermally grown oxide and a ceramic top coat that provides the main thermal shielding. Homogeneous ceramic coatings as top coats appear to have certain undesirable features such as high residual and thermal stresses, generally low toughness and relatively poor bonding strength. The new concept of compositional grading of the top coat may help to overcome some of these shortcomings by eliminating the material property discontinuities. A common mode of failure in thermal barrier coatings seems to be the debonding of the top coat. In this study the related interface crack problem for a graded ceramic/metal top coat is considered. It is assumed that the thermophysical properties of the top coat continuously vary between that of the bond coat at the top coat-bond coat interface and that of the ceramic at and near the free surface. The main objective of the study is to examine the influence of the material nonhomogeneity parameters and relative dimensions on the stress intensity factors and the crack opening displacements.

Two-point iterative methods for solving nonlinear equations

In this study, a new root-finding technique for solving nonlinear equations is proposed. Then, two new more algorithms are derived from this new technique by employing the Adomian decomposition method (ADM). These three algorithms require two starting values that do not necessarily bracketing the root of a given nonlinear equation, however, when the starting values are closed enough or bracketed the root, then the proposed methods converge to the root faster than the secant method. Another advantage over all iterative methods is that; the proposed methods usually converge to two distinct roots when the handled nonlinear equation has more than one root, that is, the odd iterations of the new techniques converge to a root and the even iterations converge to another root. Some numerical examples, including a sine-polynomial equation, are solved by using the proposed methods and compared with the secant method; perfect agreements were found.

DIFFERENCES BY SEX AND HANDEDNESS IN RIGHT AND LEFT FEMUR BONE MINERAL DENSITIES

Left-handedness was reported to be a risk factor for accident-related injuries, head injuries, traumatic brain injuries, sport-related injuries, and bone breaks and fractures. As decreased bone mineral density is a good marker of bone fractures, the femoral bone mineral densities of normal left-handed university students were compared with those of right-handed students. Hand preference of 66 men and 47 women was assessed using the Edinburgh Handedness Inventory. Measures of bone mineral density with a Hologic QDR-4500W (S/N 48403) densitometer showed bone mineral densities of both right and left proximal femur regions were higher in right-handed than in left-handed students. These results are consistent with the claim that left-handed participants had higher trauma and injury risk. Also, these results may explain the sex-related differences by handedness for susceptibility in accident-related injuries such as bone fractures.

Heart and soft-tissue uptake of Tc-99m MDP in a hemodialysis patient

Metastatic calcification related to renal failure has been well described. There is uptake of bone-scanning agents at extraskeletal sites in metastatic calcification. A 34-year-old man with end-stage renal failure was treated with hemodialysis. He noticed a painful lump over his right shoulder. Anterior and posterior whole-body bone scintigraphy images revealed markedly increased uptake in the heart, right shoulder, and medial part of the left shoulder. A biopsy of the right shoulder area showed metastatic calcium deposition.

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.

The effect of sodium pertechnetate human carbonic anhydrase I and II

The inhibitory effects of Na99mTcO4 (Sodium pertechnetate) on human erythrocyte carbonic anhydrase I and II activity were investigated. For this purpose, hCA I was initially purified 114,29-fold at a yield of 69,19 % and hCA II was initially purified 710,82-fold at a yield of 71,72 % using sepharose 4B-tyrosine-sulfanilamide affinity gel chromatography. The in vitro effect of this compound on hCA I and II isoenzyme were studied. It was detected in in vitro studies that the hCA I and II enzymes are inhibited due to Na99mTcO4.

In vitro effects of radioactive properties of 99mTc and 99mTc-MDP on human glucose 6-phosphate dehydrogenase activity

The inhibitory effects of Na99mTcO4 (Sodium pertechnetate) and Na99mTcO4-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 compounds on hG6PD enzyme were studied. It was detected in in vitro studies that the hG6PD enzyme is inhibited due to Na99mTcO4 and Na99mTcO4-metilendifosfonat (MDP).