Nurten Dikmen

Homocysteine effects on cellular glutathione peroxidase (GPx-1) activity under in vitro conditions

Hyperhomocysteinemia is associated with a lot of diseases including cardiovascular diseases and neural tube defect, but it has not been clarified exactly which mechanism is responsible for occurence disease. Here, homocysteine (Hcy) and cysteine (Cys), which are thiol containing amino acids, were examined for their effect on glutathione peroxidase (GPx) activity. İt was observed that the GPx-1 activity was inhibited under severe hyperhomocysteinemia (50–500 μM Hcy) conditions, especially at low glutathione concentrations but that cysteine increased GPx-1 activity at low glutathione concentrations and inhibition clearly appeared at 500 μM Cys concentration.

A biomimetic growth factor delivery strategy for enhanced regeneration of iliac crest defects.

The importance of provision of growth factors in the engineering of tissues has long been shown to control the behavior of the cells within the construct and several approaches were applied toward this end. In nature, more than one type of growth factor is known to be effective during the healing of tissue defects and their peak concentrations are not always simultaneous. One of the most recent strategies includes the delivery of a combination of growth factors with the dose and timing to mimic the natural regeneration cascade. The sequential delivery of bone morphogenetic proteins BMP-2 and BMP-7 which are early and late appearing factors during bone regeneration, respectively, was shown in vitro to enhance osteoblastic differentiation of bone marrow derived mesenchymal stem cells. In the present study, the aim was to study the effectiveness of this delivery strategy in a rabbit iliac crest model. 3D plotted poly(ε-caprolactone) scaffolds were loaded with BMP carrying nanoparticles to achieve: (a) single BMP-2 or BMP-7 delivery, and (b) their combined delivery in a simultaneous or (c) sequential (biomimetic) fashion. After eight weeks of implantation, computed tomography and biomechanical tests showed better mineralized matrix formation and bone-implant union strength at the defect site in the case of sequential delivery compared to single or simultaneous delivery modes. Bone mineral density (BMD) and push-out stress were: 33.65±2.25 g cm(-3) and 14.5±2.28 MPa, respectively, and almost 2.5 fold higher in comparison to those without growth factors (BMD: 14.14±1.21 g cm(-3); PS: 6.59±0.65 MPa). This study, therefore, supports those obtained in vitro and emphasizes the importance of mimicking the natural timing of bioavailability of osteogenic factors in improving the regeneration of critical-sized bone defects.

Effects of Sodium Valproate on Renal Functions in Rats

In recent years, it has been reported that sodium valproate occasionally can cause renal tubular impairment. This study was designed to demonstrate the renal tubular and glomerular functions in rats given sodium valproate as monotherapy, as well as to determine any reversibility of dysfunctions. Female rats were randomly allocated to three groups: group 1 received sodium valproate 500 mg/kg/d intraperitoneal for six weeks; after the same injection period, group 2 was housed for another six weeks, after which laboratory investigations were completed; and group 3 served as a control group made up of 20 healthy rats living in same condition without any treatment. Serum ALT, total protein, uric acid, ALP, phosphorus, sodium levels, and urine Ca/cr ratio were significantly different between groups 1 and 3 (p < 0.025), but this difference was not seen between groups 2 and 3. On the other hand, other parameters such as TRP, Ccr, NAG, and MDA were not significantly different among the three groups ( p > 0.025) These results suggest that SV does not have a significant dose- or time-related side effect on renal functions. Minor biochemical dysfunctions related to long-term sodium valproate therapy is reversible, and the minimal renal fibrosis that showed histopathologically is not clinically important. The renal tissues of rats are known to show similar metabolic and histological patterns with human renal tissues. No renal dysfunction was expected in humans because there were no clinically statistically significant renal side effects in this study.

Three new G6PD variants, G6PD Adana, G6PD Samandağ, and G6PD Balcali in Cukurova, Turkey.

SummaryGlucose-6-phosphate dehydrogenase (G6PD) enzyme from cases known to be completely or mildly deficient were analyzed. The enzymes were purified from blood samples by utilizing DEAE-52 cellulose pH 7.0 column chromatography and ammonium sulphate precipitation. Biochemical and electrophoretic properties of G6PD were studied in these partially purified enzymes. In this study wer report three new variants from Çukurova, named Adana, Samandağ, and Balcali. Variant I (G6PD Adana) had a high Km for G6P (210 μM) and NADP (13μM). Utilization of 2d-G6P was 38%. It had a slow electrophoretic mobility, a biphasic pH optimum curve, and abnormal heat stability. Variant II (G6PD Samandağ) had a low Km for G6P (25μM) and a high Km for NADP (18μM). The rate of utilization of 2d-G6P was normal. G6PD Samandağ deviated from the normal enzyme by its biphasic pH optimum curve and its slow electrophoretic mobility. Variant III (G6PD-Balcali) had a normal Km G6P, NADP and rate of utilization of 2d-G6P. However, it showed a biphasic pH optimum curve and slow electrophoretic mobility.

Superoxide Dismutase as a Prognostic Criterion in Nephrotic Syndrome

Aytül Noyan, MD, Cevat Yurdakul Cad. 54/14, TR-01120 Adana (Turkey) Dear Sir, SOD It has long been speculated that certain types of human renal disease, in particular those affecting the glomerulus, appear to be mediated by immunological mechanisms. However, little is known about the particulars of this mediation. There is evidence that phagocytes accumulate in the glomeruli and are the source of the mediators that are responsible for much of the glomerular injury. What these mediators are, on the other hand, is not clear. Recently, oxygen radicals have been reported to be responsible for glomerular injury and subsequent proteinuria [1, 2]. Several recent studies indicated that the superoxide radical (O2) played a major role in the inflammatory process, and that the enzyme, superoxide dismutase (SOD) might prove to be highly effective in the management of glomerulonephritis [3, 4]. Superoxide (O2) is an oxygen radical, which is formed by the addition of one electron to the oxygen molecule. Some superoxide is formed ‘accidentally’, when certain molecules in the body react directly with oxygen to form superoxide. Examples include the catecholamines, tetrahydrofolates etc. In addition, some superoxide is formed as a byproduct of certain immunological processes. For instance, activated phagocytes generate large amounts of superoxide as a part of the mechanism by which foreign organisms are killed. During chronic inflammation, this normally protective mechanism becomes damaging, and is in part responsible for the tissue damage which accompanies the inflammatory process. As is well known, SOD converts superoxide to hydrogen peroxide (H2O2). H202 + 02 Based on the above, we postulated that SOD levels could be used as a measure of inflammation and consequently as a prognostic criterion of the nephrotic syndrome. In this communication the preliminary data from our study are presented. The study group consisted of 20 children with nephrotic syndrome in relapse. Ten children were steroid-responsive with good prognosis and formed the first group. The remaining 10 children, which were steroid-resistant, formed the second group. When we compared the SOD levels of these groups, we found a statistically significant difference (t = 2,17, p < 0.05) as shown in table 1. Our preliminary data clearly demonstrate that SOD levels in the steroid-resistant

COMET, TUNEL, and TEM analysis of an infertile male with short tail sperm.

Male infertility is correlated with sperm morphology and sperm DNA damage, which are completely different from that of fertile individuals. An accurate sperm DNA damage analysis and ultrastructural examination of the ejaculate provide important support in the clinical evaluation. It is supposed that in the near future, the fertilization rate, pregnancy rate, and miscarriages could be predicted using the combination of these types of tests in assisted reproductive technologies (ARTs). For this purpose, we report a very rare case of an infertile man having short tail sperm. The infertile man and his wife underwent in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). During this process, we examined the ultrastructure of the ejaculated sperm with transmission electron microscopy (TEM) and calculated the sperm DNA damage with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and COMET assays. Then, we evaluated the association between sperm DNA damage and embryo quality.

Fluctuation of "sperm DNA integrity" in accordance with semen parameters, and it's relationship with infertility.

PurposeNowadays sperm analysis is used routinely to assess infertile men, but it’s predictive value is still restricted. For this reason, new markers are needed for diagnosis and guide treatment. A DNA damage evaluation method, which is easily applicable for routine analysis is described in this paper to provide an important support in clinical evaluation.MethodsIn this study, DNA damage evaluation was planned in infertile males with the COMET assay, a method which is simple, cheap, sensitive and reliable. For this purpose, the sperm DNA damage of normospermic, oligospermic, asthenospermic and teratospermic cases were investigated and the relationship between sperm parameters (sperm count, motility, morphology) and DNA damage was assessed.Results and conclusionAccording to our results we suggest that the factors to blame for sperm DNA damage and semen quality are the same. Also it was found that the infertile males possess substantially more sperm DNA damage than fertile men do. Improving and using the DNA damage evaluation tests seem to improve the results in ART clinics.

DNA Hasar Analizinde Tek Hücre Jel Elektroforezi (Komet Yöntemi)

qSingle cell gel electrophoresis (SCGE)q, also called qComet Assayq, is a sensitive, reliable and rapid technique for quantifying and analyzing DNA damage in individual cells. The comet assay is widely used in living cells, researches and the applications on comet assay is becoming broader day by day. To date, the comet assay has been used for a variety of applications, including genotoxic and cytotoxic agent analyses, environmental toxicology, cancer research, and radiation biology. Briefly, in comet assay, fully frosted microscope slides were first covered with 0.5% normal melting point agarose (NMA) and air-dried at the room temperature then cells were mixed with 0.5% low melting point agarose (LMA) at 37oC to form a cell suspension which was spread onto the slide surface and let it solidified. A third layer of 0.5% low melting point agarose was then added and again allowed to solidify. After preparing the three layer agarose the slides were immersed in lysing solution at least for an hour. The slides were then placed in an electrophoresis tank which contained neutral or alkaline buffer solution and kept in there for a short while prior to electric field application. After electrophoresis, the slides were washed with neutralization solution or PBS and stained with a DNA-specific fluorescent dye and analyzed using a fluorescent microscope.

The Effect of Parathion-methyl and Antidotes on Parotid and Pancreatic Glands: A Pilot Experimental Study

The objective of this study is to investigate the functions of parotid and pancreatic glands in response to intoxication with parathion-methyl (PM) and the effects of treatment in rats. Seventy-five male Wistar rats were divided equally into five groups: Group I, control; group II, received atropine and pralidoxime (2-PAM) for 24 h, but no PM; group III, oral PM but no atropine and 2-PAM; group IV, PM and atropine for 24 h and 2-PAM; group V, PM and atropine for 96 h and 2-PAM. After the administration of the chemicals, blood samples were drawn to test for amylase, lipase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), while pancreatic and parotid glands of each rat were removed for light microscopic examination. Amylase levels were found significantly elevated in groups II, III, IV, and V, whereas lipase levels were supranormal in groups III, IV, and V. The blood levels of AChE were decreased in groups III and IV and BChE were decreased in II, III, IV, and V. No evidence of pancreatitis and parotitis was identified in the histopathologic evaluation in any group in 96 h; however, hyperchromasia, irregularity in nuclei, and binuclear cells were observed in all parotid glands in group V. Parotitis and pancreatitis were not evident; however, hyperamylasemia and hyperlipasemia were found, whereas various histologic changes in parotid glands were documented in the groups that were administered organophosphate and treatment.