Biomedical subjects

E Kökoğlu

Publications and source records attributed to E Kökoğlu.

At least 19 recordsLinked to original sources

PubMed2000

Carbohydrate-deficient transferrin and sialidase levels in coronary heart disease.

Transferrin is a N-glycosylated glycoprotein and plays an important role in iron transport from sites of absorption and storage to sites of utilization. The main component of normal serum transferrin contains two biantennary glycans, each consisting of 2 mol of sialic acid (Tetrasialo transferrin). Normal serum also contains small amounts of tri- and disialotransferrin. We have undertaken this study to investigate the levels of serum carbohydrate-deficient transferrin (Desialotransferrin) and sialidase levels in patients with coronary heart disease. In patient group, serum desialotransferrin and sialidase levels were found to be significantly higher than control group (p < 0.01 and p < 0.001, respectively). We conclude that increased activity of sialidase may be responsible for increased desialotransferrin in patients with coronary heart disease. Serum desialotransferrin levels may be useful critaria to diagnosis and pathogenesis of coronary heart disease.

Adult↗

PubMed1999

Total acid soluble and insoluble carnitine levels in human brain tumors.

Carnitine has two main functions, i.e., transporting long-chain fatty acids into the mitochondrial matrix for beta-oxidation to provide cellular energy and modulating the rise in intramitochondrial acyl-CoA/CoA ratio, which relieves the inhibition of many intramitochondrial enzymes involving glucose and amino acid catabolism. The present study examined the acid soluble carnitine (ASCAR) acid insoluble carnitine (AICAR) and total carnitine (TCAR) concentrations of 50 human brain tumor tissues and 11 normal brain tissues. The ASCAR levels significantly higher in gliomas and meningiomas than brain, however similar to brain in metastatic adenocarcinomas. AICAR levels were lower than brain in all tumors with the exception of a medullablastoma. TCAR levels were similar to brain in all tumor types. Decreased AICAR levels may be due to increased utilization of lipids or enhanced phospholipid and cholesterol synthesis which is need for increased membrane synthesis or formation of eicosanoids. Also decreased concentrations may be a reflection of camitine and its acylesters role in preserving the physiologic membrane structure function from oxidative damage.

Adenocarcinoma↗

PubMed1998

Prostaglandin E2 levels in human brain tumor tissues and arachidonic acid levels in the plasma membrane of human brain tumors.

Arachidonic acid is stored in the cell membrane and released when the cell is activated by appropriate stimuli. It is the substrate for prostaglandins. Both experimental and human tumors often synthesize high levels of prostaglandins, most notably prostaglandin E2 (PGE2). Some experiments suggest that these compounds increase tumor growth through their actions on host immunocytes. In this study, 22 patients with various brain tumors and 12 control brain tissues were studied. PGE2 levels in tissue samples were measured by ELISA. Arachidonic acid levels in the plasma membrane of tissue samples were analyzed by capillary gas chromatography. The levels of PGE2 were significantly higher in gliomas (n = 10) and meningiomas (n = 7) compared with control tissues (P = 0.000 and P = 0.000, respectively). Also, PGE2 levels in meningiomas were significantly higher than in gliomas (P = 0.000). Arachidonic acid levels in the plasma membrane of gliomas (n = 9) and meningiomas (n = 6) were significantly higher than in the control tissues (P = 0.000 and P = 0.000, respectively). These results suggest that the increased production of PGE2 may suppress the immune system and play an important role in tumor growth.

Arachidonic Acid↗

PubMed1998

Alterations in superoxide dismutase activities, lipid peroxidation and glutathione levels in thinner inhaled rat lungs: relationship between histopathological properties.

Paint thinner has widespread use in industry. The use of thinner among children as a narcotic agent has become a social and health problem. There is some evidence that organic solvents may express their toxicity by the way of reactive oxygen species (ROS) induced cell damage. ROS has been shown to induce lipid peroxidation in biological membranes. This study examined peroxidative and histopathological changes in the rat lung, during 5 weeks of thinner inhalation. Significant increases were found in lipid peroxidation (MDA+4-DHA) levels related to the duration of inhalation. As opposed to increases in the lipid peroxidation levels, significant decreases in superoxide dismutase activities and glutathione levels were observed from the third inhalation week to the end of the fifth week. At the beginning of the inhalation slight inflammatory changes, intraalveolar and interstitial extravasation and oedema in lung parenchyma were noted. As the inhalation period extended, chronic inflammatory changes, alveolar epithelial proliferation, collapse, emphysematous changes and interstitial fibrosis in lung were detected.

Administration, Inhalation↗

PubMed1998

The distribution of tissue fibronectin and sialic acid in human breast cancer.

Our findings indicate that sialic acid and fibronectin levels in breast tumors are higher than those in normal tissues. The mean tissue fibronectin and sialic acid concentrations for patients with breast cancer were 30.90 +/- 9.68 microg/mg protein and 21.60 +/- 9.35 microg/mg protein, respectively, and for normal controls were 12.47 +/- 5.69 microg/mg protein, respectively. Tissue fibronectin and sialic acid can be important markers for human breast cancer.

Adult↗

PubMed1998

Profiles of the fatty acids in the plasma membrane of human brain tumors.

Several studies demonstrated that certain fatty acids have specific effects on tumor cells. n-3 series fatty acids (alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid) may suppress the carcinogenesis, whereas n-6 series fatty acids (arachidonic acid, linoleic acid) may exert tumor promoting effects. In this study, 19 patients with various brain tumors and 12 control brain tissues were studied. n-3, n-6, n-9 unsaturated fatty acids and certain saturated fatty acids levels were measured in the plasma membrane of tumor or control brain tissues by capillary gas chromatography. We found that the level of docosahexaenoic acid from n-3 series fatty acids was significantly lower in gliomas and meningiomas than controls (p = 0.000). Total n-3 fatty acids level was also significantly lower in tumors than controls (p = 0.000). The levels of linoleic acid, arachidonic acid and dihomogamma linolenic acid from n-6 series were significantly higher in gliomas and meningiomas compared with controls (p = 0.000). Total n-6 fatty acids level was also significantly higher in tumors than controls (p = 0.000). Furthermore, in total n-9 fatty acids, total unsaturated fatty acids and total saturated fatty acids levels, there were no significant differences in gliomas and meningiomas compared with controls (p = 0.6840, p = 0.4388 and p = 0.4343, respectively). This findings suggest that n-6 fatty acids can act as a tumor-promoting agent in human brain tumors.

Brain Chemistry↗

PubMed1997

The importance of Lp(a)-fibronectin interaction in atherogenesis.

An elevated concentration of lipoprotein (a) (Lp(a)) in serum has been considered a risk factor for coronary heart disease by various investigators. The apo(a) portion of Lp(a) binds to the carboxyterminal heparin binding domain of fibronectin. Lp(a) bound to fibronectin is internalized through the fibronectin receptor pathway and thereby causes increased accumulation of lipid and foam cell formation. In the present study, fibronectin and Lp(a) concentrations have been assayed in patients with coronary heart disease (CHD) and healthy subjects. Serum total cholesterol, triglyceride, LDL, VLDL and HDL cholesterol levels in patients with coronary heart disease were significantly different from the control group (p < 0.001). Plasma fibronectin (p < 0.05) and serum Lp(a) (p < 0.001) levels were found to be significantly elevated when compared with the control group.

Adult↗

PubMed1996

Plasma Lp(a) and t-PA-PAI-1 complex levels in coronary heart disease.

In this study we investigated serum Lp(a) and plasma t-PA-PAI-1 complex levels in patients with coronary heart disease (CHD). Serum total cholesterol, triglyceride, LDL and VDL cholesterol levels (p < 0.001) and HDL cholesterol levels (p < 0.01) in patients group were found to be significantly different from those in control group. The mean Lp(a) and t-PA-PAI-1 complex levels in patients with coronary heart disease were significantly higher as compared to control group (p < 0.001). This data indicate that the elevated levels of serum Lp(a) and plasma t-PA-PAI-1 complex may play an important role in the pathogenesis of coronary atherosclerosis.

Adult↗

PubMed1996

The prognostic importance of fibronectin and sialic acid levels in human pituitary adenomas.

In this study, fibronectin and sialic acid levels were determined in human pituitary adenomas. The mean fibronectin and sialic acid levels for human pituitary adenomas were found to be 31.64 +/- 15.82 microgram/mg protein and 21.90 +/- 9.82 microgram/mg protein, respectively, versus 6.30 +/- 2.96 microgram/mg protein and 9.88 +/- 2.81 microgram/mg protein for the normal brain tissues. Fibronectin and sialic acid levels were significantly higher (P < 0.001) in human pituitary adenomas than the normal brain tissues. In human infiltrative and non-infiltrative pituitary adenomas, the mean fibronectin and sialic acid levels were found to be 40.87 +/- 15.90 microgram/mg protein, 27.59 +/- 11.10 microgram/mg protein and 22.40 +/- 9.51 microgram/mg protein, 16.21 +/- 3.20 microgram/mg protein, respectively. Fibronectin and sialic acid levels were slightly elevated (P < 0.05) in human infiltrative pituitary adenomas compared with non-infiltrative adenomas.

Adenoma↗

PubMed1996

Tissue sialic acid and fibronectin levels in human prostatic cancer.

We investigated the tissue concentration of sialic acid and fibronectin in patients with prostatic cancer. The mean sialic acid and fibronectin levels in patients with prostatic cancer were 19.02 +/- 6.30 micrograms/mg protein, respectively versus 13.01 +/- 4.53 micrograms/mg protein and 11.77 +/- 6.74 micrograms/mg protein for normal prostatic tissues. Sialic acid and fibronectin levels in cancerous patients were significantly higher than in the control group (P < 0.05).

Biomarkers, Tumor↗

PubMed1996

The relationship between the electrophoretic mobility of lipoproteins and coronary heart disease.

Low density lipoproteins (LDL) in patients with coronary atherosclerosis have a substantially lower content of sialic acid when compared with the LDL from healthy subjects. Desialylated LDL have smaller sizes and greater electrophoretic mobilities than sialylated ones. Desialylated LDL may be responsible for the accelerated development of foam cells in atherosclerosis. In the present study, we investigated a relationship between the electrophoretic mobility of lipoproteins and the number of significantly obstructed vessels in patients with coronary heart disease (CHD). Our findings indicate that when the number of significantly obstructed vessels is increased, the electrophoretic mobility of lipoproteins is high. We also investigated the possible role of serum sialidase activity on lipoprotein desialylation in patients with coronary heart disease. In patients with single vessel disease (p < 0.01) and double-triple vessel disease (p < 0.001) the mean serum sialidase activity was significantly higher than in the control group.

Adult↗

PubMed1995

Fibronectin and sialic acid levels in human meningiomas and gliomas.

In this study, fibronectin and sialic acid levels have been assayed in human meningiomas and gliomas. The mean fibronectin and sialic acid levels for human meningiomas were 22.01 +/- 9.70 micrograms/mg protein and 19.58 +/- 4.89 micrograms/mg protein, respectively, and for human gliomas were 27.30 +/- 13.70 micrograms/mg protein and 25.67 +/- 11.60 micrograms/mg protein, respectively, versus 9.23 +/- 5.40 micrograms/mg protein and 13.50 +/- 4.30 micrograms/mg protein for normal brain tissues. Fibronectin and sialic acid levels were significantly higher in human meningiomas (P < 0.01 and P < 0.05) and gliomas (P < 0.001 and P < 0.01) than control group. Also the mean fibronectin and sialic acid levels were found to be 18.27 +/- 7.08 micrograms/mg protein and 17.04 +/- 6.25 micrograms/mg protein in Grade I-II and 32.60 +/- 15.00 micrograms/mg protein and 29.50 +/- 11.60 micrograms/mg protein in Grade III-IV gliomas, respectively. Fibronectin and sialic acid levels were significantly higher in Grade III-IV gliomas than Grade I-II gliomas (P < 0.05).

Biomarkers, Tumor↗

PubMed1995

Plasma fibronectin and sialic acid levels in various types of human brain tumors.

In this study, fibronectin and sialic acid concentrations were determined in plasma from patients with pituitary adenoma, meningioma and glioma, and, from controls. The mean plasma fibronectin levels in patients with pituitary adenoma, meningioma and glioma (p < 0.001) appeared to be significantly lower than controls. On the contrary, the mean plasma sialic acid values in patients with pituitary adenoma (p < 0.01), and glioma (p < 0.001) were significantly higher as compared to normal plasmas. The mean plasma sialic acid values in patients with meningioma were not different from those in controls. Also, the mean fibronectin levels in patients with glioma were found to be significantly higher than those in patients with meningioma (p < 0.05).

Adenoma↗

PubMed1995

Tissue fibronectin levels of human prostatic cancer, as a tumor marker.

In this study, tissue fibronectin levels have been assayed in human prostatic cancer, benign prostatic hyperplasia and normal prostatic tissue. The mean tissue fibronectin levels for prostatic cancer, benign prostatic hyperplasia and normal groups were found to be 20.22 +/- 8.66 micrograms/mg protein and 11.77 +/- 6.74 micrograms/mg protein, respectively. In the malignant group, the mean fibronectin concentrations, appeared to be significantly higher than normal, (p < 0.05). On the other hand, fibronectin levels of benign prostatic hyperplasia were found to be statistically insignificant in comparison to the normal group (p > 0.05).

Biomarkers, Tumor↗

PubMed1994

Alterations of serum lipids and lipoproteins in breast cancer.

Serum triglycerides, total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low density lipoprotein (VLDL) cholesterol levels were quantified in Stage I and Stage IV breast cancer patients in order to evaluate the changes in serum lipids and lipoproteins in the early and advanced stages of the disease. When compared with data from age-matched healthy females, fasting serum triglycerides and VLDL cholesterol levels were found to be significantly increased and HDL cholesterol levels significantly decreased in patients with breast cancer. Furthermore, a significant increase in triglycerides and VLDL cholesterol and decreases in total, HDL and LDL cholesterol levels were demonstrated in patients with Stage IV disease when compared to those with Stage I breast cancer. No significant difference was found in total and LDL cholesterol between Stage I breast cancer patients and healthy controls.

Breast Neoplasms↗

PubMed1994

Elevated serum Lp(a) levels in the early and advanced stages of breast cancer.

Recently, lipoprotein (a) [Lp (a)] levels were found to be elevated in various types of cancer. This study was designed to evaluate the role of serum Lp (a) in early and advanced stages of breast cancer. Fasting venous blood samples were collected from 18 patients with Stage I, and 21 patients with Stage IV disease and were analysed for Lp (a). The results were compared with data from 22 healthy female controls. Patients with both Stage 1 and Stage IV disease had significantly higher (p < 0.001) Lp (a) concentrations than did healthy controls. Lp (a) was also found to be significantly elevated in Stage IV patients when compared with the Stage I group. Our data suggest that there is a highly significant association between Lp (a) and the presence and progression of breast cancer, and the serum Lp (a) determination may provide an aid in patients with breast cancer for both diagnostic purposes and the follow-up of the disease.

Adult↗

PubMed1992

Tissue lipid composition of human gliomas and meningiomas.

This study is a comparative analysis of some lipid fractions in human brain tumors and normal brain tissue. Gliomas and meningiomas were studied and in these tumors while total lipid, total and free cholesterol and total phosphoglyceride levels were found to be significantly lower than in normal controls, the difference in esterified cholesterol levels was found to be insignificant. No significant differences in lipid fractions existed between gliomas and meningiomas except total and esterified cholesterol values.

Cholesterol↗

PubMed1992

Sialic acid levels in various types of cancer.

Serum or plasma total sialic acid (TSA) and lipid bound sialic acid (LSA) are useful markers for human cancer. In this study, sialic acid levels have been demonstrated in various types of human cancer including brain, thyroid and Hodgkin's. TSA was found to be significantly elevated in various human brain tumors, especially in the microsomal fraction. Also serum and tissue LSA levels indicated significant increases when compared to the normals in various brain and thyroid tumors. TSA levels were significantly higher in the plasma and leucocyte in patients with Hodgkin's. The results show that sialic acid can be advisable as a beneficial marker for detecting malignancies. But it can not be used as a criteria for identifying tumor types.

Adult↗