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Biomedical subjects

G Oztürk

Publications and source records attributed to G Oztürk.

At least 19 recordsLinked to original sources
PubMed2006

Nitric oxide levels during erythroid differentiation in K562 cell line.

Nitric oxide (NO) is endogenous mediator of numerous physiological processes that range from regulation cardiovascular function and neurotransmission to antipathogenic and tumoricidal responses. This study was designed to investigate the possible role of NO during erythroid differentiation in K562 erythroleukemia cells. The chronic myelogenous leukemia (K562) cell line can be triggered in culture to differentiate along the erythrocytic pathway, in response to a variety of stimulatory agents. In this study, K562 cells were induced to synthesize hemoglobin by hemin. We investigated NOx (nitrate+nitrite) levels in uninduced (control) and hemin-induced K562 cell lysates during erythroid differentiation. Our results showed that NO levels decreased significantly on fourth and sixth day both in hemin-induced and control cells; the decrease was, however, more in hemin-induced group than in control group.

Biochemistry↗
PubMed2005

Effect of leukemia inhibitory factor in experimental cisplatin neuropathy in mice.

In this study, the effect of leukemia inhibitory factor (LIF) on cisplatin (CDDP)-induced neuropathy was evaluated. Mice were treated with CDDP, 2 mg/kg i.p. twice a week nine times. During the last week some of the mice were also injected with LIF, 2 mug/kg s.c. every other day for a total of four injections. Development of neuropathy was evaluated with changes in tail flick latency and sensory nerve conduction velocity (NCV). At the end of the treatment period dorsal root ganglia (DRG) were microscopically examined. Some of the DRGs were explanted into extracellular matrix, covered with culture medium and incubated for 3 days. During and at the end of the incubation, cellular migration and axonal outgrowth from the DRGs were quantified. LIF proved effective in reversing the increase in tail flick latency (p<0.05) and improving the reduction in NCV induced by CDDP. CDDP led to smaller nuclear and somatic size in neurons, while with LIF, the latter was restored to control values (p<0.01). No apoptotic nucleus was observed among DRG neurons while very few and moderate numbers detected among satellite and Schwann cells, respectively. With LIF, none of the cells had apoptosis. CDDP caused a decrease in the number of migrating cells and in the length of outgrowing axons while LIF treatment restored both capacities (p<0.05) In conclusion, in CDDP-induced neuropathy, LIF was found to be effective in correcting some functional and morphological deteriorations related with major involvement of Schwann cells.

Analysis of Variance↗
PubMed2005

Spontaneous rupture of hepatocellular carcinoma: a case report and review of literature.

Hepatocellular carcinoma (HCC) has a tendency for fatal spontaneous rupture leading to massive haemorrhage. A 64-year-old man presented with sudden, severe epigastric pain for 6 h. Systolic blood pressure was 80/50 mmHg, and pulse rate was 100/min. The patient's history did not reveal any operation or disease up to date. Contrast enhancement-axial computed tomography (CT) scan showed a tumoral lesion with a necrotic centre measuring 6 x 5 cm within 6th segment of the liver and a fluid collection (haemoperitoneum) at the periphery of the liver. At exploratory laparotomy, the liver was found to be cirrhotic, and an actively bleeding tumour confirmed in 6th segment of the liver. The tumour was resected. Post-operative recovery was unremarkable, and the patient was discharged on the 14th post-operative day. Ruptured HCC should be included in the differential diagnosis of non-traumatic intra-abdominal haemorrhage.

Carcinoma, Hepatocellular↗
PubMed2005

The effect of short-term treatment with atorvastatin on E-selectin levels in severely burned patients.

Cellular adhesion molecules are expressed by activated endothelial cells in severe bum. The release of these molecules can lead to organ damage. We measured E-selectin levels in the blood of 20 severe-burn patients. Then the patients were divided into two groups of 10 patients each. In the study group, atorvastatin 20 mg/day was administered orally for 14 days. In the control group, an equal volume of placebo was administered orally for 14 days. In both groups, following the last dose of the agents, serum E-selectin levels were measured again. Mean burn size and the percentage of third-degree bums of total burned area were not significantly different between the groups. Serum E-selectin level obtained at the beginning of the treatment was 23.69 +/- 2.71 ng/ml in the atorvastatin group and 18.08 +/- 0.97 ng/ml in the control group. Serum E-selectin level obtained at the end of the treatment was 10.86 +/- 1.36 ng/ml in the atorvastatin group and 21.69 +/- 2.11 ng/ml in the control group. The difference between the two groups was statistically significant (p < 0.05). In the comparison of early and late serum E-selectin levels in the atorvastatin group, a significant decrease was obtained (p < 0.05). In the control group, serum E-selectin levels were found to be increased in the late period. However, the difference between the early and late values was nonsignificant (p > 0.05). We concluded that atorvastatin is effective in the prevention of E-selectin release in severely burned patients.

Adolescent↗
PubMed2004

A novel amperometric biosensor based on artichoke (Cynara scolymus L.) tissue homogenate immobilized in gelatin for hydrogen peroxide detection.

A biosensor for specific determination of hydrogen peroxide was developed by using homogenized artichoke (Cynara scolymus L.) tissue in combination with a dissolved oxygen probe and applied in determination of hydrogen peroxide in milk samples. Artichoke tissue, which has catalase activity, was immobilized with gelatine by means of glutaraldehyde and fixed on a pretreated teflon membrane. The electrode response was maximum when 0.05 M phosphate buffer was used at pH 7.0 and at 30 degrees C. Upon addition of hydrogen peroxide, the electrode gives a linear response in a concentration range of 5.0-50 x 10(-5) M with a response time of 3 min. The method was also applied to the determination of hydrogen peroxide in milk samples.

Animals↗
PubMed2003

Hepatoprotective effect of Foeniculum vulgare essential oil.

Hepatoprotective activity of Foeniculum vulgare (fennel) essential oil (FEO) was studied using carbon tetrachloride (CCl(4)) induced liver injury model in rats. The hepatotoxicity produced by acute CCl(4) administration was found to be inhibited by FEO with evidence of decreased levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin. The results of this study indicate that FEO has a potent hepatoprotective action against CCl(4)-induced hepatic damage in rats.

Alanine Transaminase↗
PubMed2001

Effects of leukemia inhibitory factor on galanin expression and on axonal growth in adult dorsal root ganglion neurons in vitro.

Synthesis of leukemia inhibitory factor (LIF) is increased in lesioned peripheral nerves and it is thought that this may cause increased expression of galanin (GAL) in axotomized dorsal root ganglia (DRG) neurons and also to promote axonal regeneration. We therefore compared effects of LIF and nerve growth factor (NGF) on galanin expression and axonal growth using cultured intact DRGs of adult mice. In control lumbar DRGs cultured for 3 days, only 16% of neurons were immunoreactive for GAL, but this was increased to 38% in preparations cultured with LIF. NGF by itself had no effect on GAL expression, but the proportion of GAL-positive neurons in cultures incubated with LIF and NGF together (22%) was less than that observed in DRGs cultured with LIF alone. Similar results were obtained using thoracic DRGs. In collagen gels, NGF caused marked increases in the numbers and lengths of outgrowing axons as observed in previous studies. In contrast, LIF did not stimulate axonal outgrowth but increased the proportions of axons which were immunoreactive for GAL. The results indicate that expression of LIF in lesioned nerves may affect expression of neuropeptides such GAL rather than stimulating axonal regeneration.

Animals↗
PubMed2001

Synthesis of 4(1H)-pyridinone derivatives and investigation of analgesic and antiinflammatory activities.

This paper describes recent results of a research program aimed at the synthesis and pharmacological evaluation of new 4(1H)-pyridinone derivatives belonging to the 1,3-disubstituted series (4-11). These compounds were structurally planned by applying the molecular hybridization strategy on previously described 1,2-disubstituted-4(1H)-pyridinone derivatives, considered as lead compounds, which present potent analgesic properties (M.D. Aytemir, T. Uzbay, D.D. Erol, Arzneim. Forsch. (Drug Res.) 49 (1999) 250). Their chemical structures have been proved by means of their IR and 1H NMR data and by elemental analysis. The analgesic profile of the title compounds (4-11), evaluated by the model of abdominal constrictions induced by acetic acid, showed that all the 4(1H)-pyridinone derivatives were active, exhibiting an analgesic activity comparable with that of aspirin (acetyl salicylic acid) used as a standard. The antiinflammatory profile of the synthesized compounds, evaluated by the model of carrageenan rat paw edema, showed that all compounds were active and were comparable with indomethacin used as a standard.

Analgesics, Non-Narcotic↗
PubMed2001

Impact of stress, gender and menstrual cycle on immune system: possible role of nitric oxide.

Stress is a factor found to be involved in the etiology of many diseases. Gender and menstrual cycle phases are other factors affecting the predisposition of individuals for certain diseases. Results from animal and human studies suggest that the distribution of immune system cells may change at different phases of the menstrual cycle. Acute mental stress in humans alters immune variables, too. The increase in the number of natural killer (NK) cells is the most consistent finding among the immune variables, though there are controversies for the other lymphocyte groups. Nitric oxide (NO) as an immune mediator has an unsettled role whether it causes the redistribution of the immune cells, or is an end product of lymphocyte activation. This study was planned to investigate the effect of mental stress on lymphocyte subtypes and the role of NO, for men and women at different phases of the cycle. For this purpose, healthy men (n = 10) and women (n = 10), during the follicular and luteal phases underwent Stroop colour-word interference and cold pressor tests. The immune system responses before and after the tests were determined by cell counts with the flowcytometer. Menstrual cycle phase was ascertained by plasma estrogen and progesterone measurements. Stress response was evaluated by blood pressure (BP) and heart rate (HR) measurements throughout the tests and plasma cortisol and urinary metanephrine and vanillylmandelic acid (VMA) measurements before and after the tests. Plasma and urinary NO determinations were performed before and after the test was completed. All the results were analysed with the appropriate statistical methods. The luteal phase differed from the other groups due to the presence of suppressed immune response to acute stress, including decreased CD4/CD8 ratio and NK cell percentage. On the other hand, acute stress caused a shift from cellular to humoral immunity in men. As indicated by these results, individual reaction towards stress is affected by gender and menstrual cycle phase. NO appears to be a possible effector molecule for these differences.

Adult↗
PubMed2001

Natural killer cell activity, serum immunoglobulins, complement proteins, and zinc levels in patients with psoriasis vulgaris.

The role of the immune system in patients with psoriasis vulgaris (PV) was investigated. The genetic and immunological basis for psoriasis is still unknown. Because of the reports of immunological defects in this disease, we investigated serum levels of immunoglobulins IgG, IgM, IgA, complement proteins C3, C4, serum zinc (Zn) levels and natural killer (NK) cell activities. Skin lesions of the psoriatic patients involved in the study comprised less than 10 % of the total body and the disease was in a stationary period. Zn levels were measured by atomic absorption spectrophotometry. NK cell activity was measured by 51Cr (Na2 51CrO4). IgG, IgA, IgM, C3 and C4 assays were done by liquid-phase immunoprecipitation assay with nephelometric endpoint detection. IgG, IgA, C3 and C4 levels were significanty higher in patients with PV than in healty controls (p < 0.05). However, NK cell activity, serum Zn and IgM levels did not show significant differences between these two groups. There are changed immunological responses, which may play an important role in the pathogenesis of the disease. Many controversial results have been related to immunological parameters in psoriatic patients. Therefore, more detailed studies in this field need to be done to determine the relationship between psoriasis and the immune system.

Adolescent↗
PubMed2001

Vitamin C decreases intracellular calcium level in human lymphoid cells.

Human lymphocytes have low levels of many antioxidant enzymes however they are know to concentrate vitamin C. Cell injury, including oxidative stress effects, is associated with calcium influx so the influence of vitamin C on the maintenance of calcium levels in leukocytes was studied. Incubation of Molt-3 human lymphoblastoid cells with physiologically relevant concentrations of vitamin C and the calcium ionophore A23187 reversed the calcium influx and increased nuclear protein level associated with the ionophore alone. It is concluded that intracellular vitamin C can inhibit calcium influx into leukocytes so helping to minimise cell damage.

Antioxidants↗
PubMed2000

National survey of hemapheresis practice in Turkey (1998).

The Turkish Apheresis Group has maintained a national registry for apheresis activities since 1997. The hemapheresis practice of Turkey in 1998 is summarized in brief detail in this article. A total of 30, 136 apheresis procedures were performed at 31 different apheresis centers. At 10 centers, 145 peripheral blood stem cell (PBSC) apheresis were performed on 82 patients in allogeneic setting and at 17 centers, 981 PBSC apheresis were performed on 271 patients in autologous setting. Frequently observed adverse effects during PBSC apheresis were mild tremor and chills, paresthesia and nausea in 15% of the patients and donors. Vascular access complications, particularly observed in autologous setting due to central venous catheters were encountered in 10% of the procedures. Eight hundred and sixty-nine therapeutic plasma exchange procedures were performed at 21 centers on 172 patients, most commonly for neurological disorders and thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS). Therapeutic cytapheresis procedures like leukapheresis, plateletapheresis and erythrocyte apheresis were performed especially for cytoreduction in myeloproliferative disorders. A total of 204 cytapheresis procedures (66% leukapheresis, 33% plateletapheresis and 1% erythrocytapheresis) were performed on 134 patients in 15 centers. Donor plateletapheresis was the most used apheresis procedure, reaching a total of 28.016 in 1998. Many university hospitals and a few state hospitals are performing above-mentioned apheresis procedures with great success and acceptable side effects. According to these data we are planning prospective trials and will establish National Standards of Practice.

Adolescent↗
PubMed2000

Thrombosis during all-trans-retinoic acid therapy in a child with acute promyelocytic leukemia and factor VQ 506 mutation.

Acute promyelocytic leukemia (APL) is often associated with a severe hemostatic disorder, caused by the release of procoagulant and fibrinolytic substances from leukemic blasts. The coagulation profile may exhibit disseminated intravascular coagulation and fibrinolysis or proteolysis. Therefore, heparin and antifibrinolytic agents alone or in combination have been used to prevent severe bleedings. Remission induction with all-trans-retinoic acid (ATRA) is accompanied with rapid correction of hemostatic abnormalities. Thrombosis is a rare complication of APL and may be due to the alterations in hemostasis caused by the disease itself as well as ATRA and antifibrinolytics. Here, the occurrence of thrombosis during induction treatment with ATRA combined with aprotinin and chemotherapy is described in a patient who is homozygous for factor VQ 506 mutation.

Adolescent↗
PubMed2000

A viable residual spinal hydatid cyst cured with albendazole. Case report.

Spinal hydatid disease is a rare entity that frequently yields to severe, acute-onset neurological deficits. Although the gold standard treatment is total surgical removal of the cysts without inducing any spillage, it may not be possible to perform this in patients with multiple and fragile cysts. In such cases, the neural structures should be adequately decompressed and albendazole should be administered promptly. The authors describe the case of a 13-year-old girl who was admitted with a history of back pain and acute-onset lower-extremity weakness. Magnetic resonance imaging scans demonstrated severe spinal cord compression caused by multiple cysts involving T-4 and the mediastinum. The patient underwent surgery, and the cysts were removed, except for one cyst that was hardly exposed. Following histopathological confirmation of spinal hydatid disease, she was treated with albendazole for 1 year. One year postoperatively, the residual cyst had gradually shrunk and had almost disappeared. Although a single case is not sufficiently promising, we believe that administration of albendazole is efficient to prevent recurrences in cases in which it is not possible to obtain total removal of the cysts without inducing spillage.

Adolescent↗
PubMed2000

The effect of steroid and intravenous immunoglobulin on thrombopoietin levels in pediatric patients with immune thrombocytopenic purpura.

Thrombopoietin (TPO), which is the main regulator of megakaryo/thrombopoiesis, has been recently cloned and purified, and shown to be useful in discriminating thrombocytopenia due to decreased production or increased platelet destruction. However, there are no detailed investigations about the drug effects on TPO levels during childhood. This study was conducted to measure the TPO levels of children with immune thrombocytopenic purpura (ITP) during steroid and immunoglobulin treatment. Twelve patients with acute ITP were treated with high-dose methyl prednisolone and five patients were treated with intravenous immunoglobulin. Neither steroids nor immunoglobulin were found to have any effect on TPO levels.

Acute Disease↗
PubMed1999

[Cowden syndrome (multiple hamartoma syndrome). Role of the dentist in early detection].

First lesions of Cowden syndrome appear in the oral cavity and on the skin. Malignant transformation is a late, common event in thyroid and breast. The early diagnosis of Cowden disease prior to the development of internal malignancy, particularly of the breast and the thyroid gland, is very important. We emphasize that the dentist may be the first health care professional who recognizes the syndrome, and this is a crucial step in the prevention and cure of the predictable malignancy. This article presents a typical case of Cowden disease.

Adult↗