PubMed Health⌕ Search

Biomedical subjects

E Bakan

Publications and source records attributed to E Bakan.

At least 19 recordsLinked to original sources
PubMed2006

Effects of type 2 diabetes mellitus on plasma fatty acid composition and cholesterol content of erythrocyte and leukocyte membranes.

Insulin resistance is a major factor in the pathogenesis of type 2 diabetes mellitus (T2DM) and is related to the fatty acid profile of the plasma membranes. The purpose of the present study was to investigate fatty acid composition and cholesterol content of cell membranes in patients with type 2 diabetes and, thus, to evaluate the possible factors leading to the alteration of plasma membrane fluidity. The study was performed in 20 healthy control subjects and 32 patients with type 2 diabetes. The fatty acid profiles and cholesterol content of the erythrocyte (RBC) and leukocyte (WBC) membranes were determined by a gas chromatographic method. When one considers the membrane constituents increasing fluidity and the ones decreasing it, the diabetics had a membrane composition decreasing fluidity compared to controls. On the other hand, when compared to control subjects, type 2 diabetic patients showed a significantly higher proportion of C16:0 components in erythrocyte and leukocyte membranes and plasma samples (25.4+/-3.1% vs. 31.1+/-4%; 23.3+/-2.4% vs. 29.3+/-5.2%; 27.6+/-3.9% vs. 34.5+/-5.7%; p<0.005, p<0.01 and p<0.005, respectively). Our results suggest that the ratio of saturated:unsaturated fatty acids changes in plasma and cell membranes of patients with type 2 diabetes. This situation may cause, at least in part, RBC-WBC function abnormalities and insulin resistance because of inconvenient membrane fluidity.

Adult↗
PubMed2005

Hyperhomocysteinaemia as a risk factor for deep-vein thrombosis.

OBJECTIVE: Several studies have shown a relation between hyperhomocysteinaemia and vascular disease. To assess the risk of deep-vein thrombosis (DVT) associated with hyperhomocysteinaemia, we studied plasma homocysteine levels in patients with deep-vein thrombosis and in normal control subjects. MATERIALS AND METHODS: We measured plasma homocysteine levels in 48 patients with deep-vein thrombosis and in 33 healthy controls matched to the patients according to age and sex. Plasma homocysteine levels were measured with high performance liquid chromatography and fluorescence detection. Hyperhomocysteinaemia was defined as a plasma homocysteine level about 15 micromol/L in both groups. The diagnosis of all patients with deep-vein thrombosis (n=48) was verified by Doppler ultrasonography. RESULTS: Plasma homocysteine levels were found to be increased in the deep-vein thrombosis group compared the control group (p<0.001, t-test). The mean plasma homocysteine level in the patients was 17.1 SD 5.13 micromol/L (range 6.4-31.3), and that in the controls was 9.0 SD 1.27 micromol/L (range 6.0-11.5). The association between elevated homocysteine levels and venous thrombosis was stronger among men than among women. CONCLUSIONS: The increased plasma homocysteine levels we have observed may have a causative role in the development of deep-vein thrombosis.

Adult↗
PubMed2005

Changes in nitric oxide levels in striated muscles of rats following different types of death.

BACKGROUND: Nitric oxide is a signal molecule regulating the organism functions in living bodies. The aim of this study was to investigate the NO levels of striated muscles after different types of death in rats. METHODS: Nitric oxide levels in the muscles of masseter, triceps, and quadriceps obtained from right and left sides of 24 Spraque-Dawley rats following death were investigated. The rats were divided into three groups as cervical dislocation (control) group, electric shock group, and drowning group. After applying a light anesthesia, the rats were killed by cervical dislocation, electric shock and drowning. The samples were taken immediately and 120 minutes after death. RESULTS: In all muscle types of all groups, NO concentrations were lower in samples obtained 120 minutes after death than in those obtained immediately after death. NO concentrations were lower in the electric shock and drowning group than in the control group for both times. CONCLUSION: We can conclude that the type of death may affect the occurrence of rigor mortis and NO measurement may give an important clue in evaluation the mode of death.

Animals↗
PubMed2002

Lipid peroxidation, some extracellular antioxidants, and antioxidant enzymes in serum of patients with rheumatoid arthritis.

The aims of our study were to assess whether the increased oxidative stress in inflamed joints is reflected by serum lipid peroxidation and also to check alterations in the levels of extracellular antioxidants and antioxidant enzyme activities in patients with rheumatoid arthritis. Serum malondialdehyde and ceruloplasmin levels and the activity of CuZn superoxide dismutase were higher, while transferrin levels and the activities of glutathione peroxidase and catalase were lower in patients (n = 37) than in healthy controls (n = 30). Disease activity score correlated positively with serum malondialdehyde level and CuZn superoxide dismutase activity. Probably, superoxide radicals in serum could be dismutated to produce hydrogen peroxide by increased CuZn superoxide dismutase activity, but hydrogen peroxide could not have been detoxified due to decreased activities of serum glutathione peroxidase and catalase. Hydrogen peroxide possibly converted to hydroxyl radical by iron due to lower transferrin level might have led to increased serum lipid peroxidation in patients with rheumatoid arthritis.

Adult↗
PubMed2002

Serum lipoprotein(a) level and its clinical significance in patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a classic autoimmune disease characterised by the production of autoreactive T cells and autoantibodies that may affect every organ system. It has long been established that there is a close association between cholesterol- rich lipoproteins (such as low-density lipoprotein-cholesterol) and cardiovascular disease in patients with SLE. In this study, we evaluated total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, VLD-cholesterol, apolipoprotein A-1, apolipoprotein B, and cholesterol-rich serum lipoprotein(a) [Lp(a)], which is accepted to be an independent risk factor for cardiovascular disease and for atherosclerosis, in 24 patients (mean age +/- SD 31.4 +/- 9.7 years, range 16-47, 22 F) with active SLE. Twenty-six healthy age- and sex-matched (mean age +/- SD 29.7 +/- 11.3 years, range 18-49 years, 22 F) subjects were included as a control group. In patients with SLE Lp(a) levels, total cholesterol, triglycerides and VLDL-cholesterol were found to be higher and HDL-cholesterol, apolipoprotein A-1 to be lower than those of controls. In conclusion, because serum Lp(a) levels are significantly higher (P<0.01) in patients with SLE, these patients have a risk of developing cardiovascular disease and atherosclerosis. Patients with SLE should be followed up with this in mind.

Adolescent↗
PubMed2001

The activities of carbonic anhydrase and alkaline phosphatase in ancient human bones. Purification and characterization of outer peripheral, cytosolic, inner peripheral, and integral CA.

In the present study, bone carbonic anhydrase was isolated from ancient human bones and its characteristic features were determined. For this purpose, the skull bone of about 3000 years age was used. The purification was performed in four steps. Four different isoenzymes of CA, including outer peripheral, inner peripheral, integral, and cytosolic were purified and characterized. Affinity chromatography using Sepharose-4B-L-tyrosyn sulfanilamide as a support material was used in its purification. Two different methods were used for enzymatic activity determination: a) hydratase, and b) esterase methods. Bradford and Coomassie Brillant Blue methods were used for protein determination. Optimal pH, temperature, and molecular weight determinations were performed by conventional methods. The purification degree and the subunits, if present, were determined by SDS-PAGE. The effects of some chemicals on the enzyme were also investigated. The most cardinal finding was that the enzymatic activity has been found in antique human bone, showing some other enzymatic activity. That the alkaline phosphatase activity has been determined in the same sample supports the finding of carbonic anhydrase.

Alkaline Phosphatase↗
PubMed2000

Purification and characterization of carbonic anhydrase from bovine erythrocyte plasma membrane.

Carbonic anhydrase (CA) was purified from bovine erythrocyte plasma membrane and characterized in this study. For this purpose, the blood taken from young animals was hemolysed, the membrane fraction was separated, and this fraction was repeatedly washed. The enzyme (CA) was removed from the membrane with buffered TritonX-100 (1%); it could be purified at a factor of 22.8 by affinity chromatography. The CA obtained from erythrocyte membrane has an esterase activity as well as hydratase activity. The Vmax and Km of the enzyme for the substrate (p-nitrophenyl acetate) are 1.948x10(-3) mM/L x dak, and 3.596 mM, respectively. The purification degree of the enzyme was controlled by SDS-PAGE (3-10), which showed two distinct bands. It was determined that the enzyme had activity within the pH range of 4.5-9.5 and that the optimal pH was 7.5. The temperature at which it showed activity was 20-60 degrees C and optimal temperature was 37 degrees C. Molecular weight of CA was found to be 29844 and 61706 Dalton by gel filtration. On the other hand, sulfanilamide and acetazolamide affected the enzyme.

Animals↗
PubMed1997

A different structural feature for carbonic anhydrases in human erythrocytes.

This study presents a different structural feature for carbonic anhydrase in human erythrocytes. Carbonic anhydrase isozymes (CA-I and CA-II) were purified from an erythrocyte pool of 20 healthy subjects. For purification, Sepharose-4B-L-tyrosine-sulfanilamide affinity column was used. Resnets from 3-10% discontinuous SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed a single band for CA-I and two distinct bands for CA-II. The molecular weights of the two bands were similar. One peak for CA-I and two peaks for CA-II were obtained in gel filtration. The enzymatic activities of the bands in question were also of different value. Native electrophoresis showed two bands for CA-I, and it showed three bands for CA-II. It can be concluded that CA-I is a polymer composed of a single promoter and CA-II has three different polymers composed of two distinct promoters, suggesting a new structural feature of human erythrocyte carbonic anhydrase isozymes.

Carbonic Anhydrases↗
PubMed1995

Maximal airway response in mature and immature rabbits during tidal ventilation.

Airway closure during maximal methacholine (MCh) challenge was evaluated using alveolar capsules in eight immature and eight mature anesthetized rabbits in vivo during imposed tidal ventilation. Changes in airway opening and alveolar pressures (delta PA) and pulmonary resistance (RL) were measured during MCh challenge at a positive end-expiratory pressure of 5 cmH2O. In immature rabbits, delta PA remained > 3 cmH2O in all animals, indicating no detectable airway closure. This contrasts to our previous study of isolated immature rabbit lungs under static conditions in which delta PA was < 0.1 cmH2O during maximal MCh challenge, findings consistent with airway closure. Airway closure also did not occur in mature animals during tidal ventilation in vivo; however, the frequency of closure in isolated lungs under static conditions was very low. With increasing MCh, end-expiratory PA increased in immature but not in mature rabbits. RL did not reach a plateau in immature rabbits during MCh, whereas a plateau was reached in mature rabbits. Immature rabbits also had greater increases in RL. These results suggest that tidal ventilation can limit bronchoconstriction in immature rabbits and prevent airway closure during maximal MCh challenge. Tidal ventilation may limit bronchoconstriction by inhibitory effects of stretch on airway smooth muscle contraction and also by causing hyperinflation and thereby increasing transpulmonary pressure.

Aging↗
PubMed1993

Pendred's syndrome.

Although 5% of all cases of congenital deafness are caused by Pendred's syndrome, there are few reports in the literature. Seven patients with Pendred's syndrome in three families living in the same village were detected. For that reason, the syndrome is reviewed in light of the literature. The sex distribution of the patients with Pendred's syndrome and their families was recorded. We tested for thyroxine, triiodothyronine, thyroid-stimulating hormone, triiodothyronine resin uptake, and perchlorate, and performed caloric testing. In one patient, subtotal thyroidectomy was performed. In the histopathologic study, a thyroid nodule filled with colloid was found. Chromosome studies showed no anomalies in any patient. Five of the patients were deaf-mutes. We observed that the parents were cousins in all three families. These families also had healthy children, and the existence of the syndrome in both sexes points to an autosomal recessive trait.

Adolescent↗
PubMed1993

Bilateral parotid duct fistula. Case report.

Parotid duct fistulas (PDFs) are rare and have various causes such as gunshot wounds and human and animal bites; they may also be congenital. We have not found previous publications on bilateral PDF. Our patient, although young, also had generalized pigmentation characteristic of aging and thick, dry, wrinkled skin, as well as pyoderma. Biochemical analysis was performed on discharge from the patient's face, and histopathologic and immunologic studies were done. The fistulas were treated by intraoral fistulization. Cephalosporins were given to the patient for 5 days postoperatively to treat the pyoderma.

Child↗
PubMed1993

Grasp reflex strength from right and left hands is associated with pH stressor from the umbilical arterial blood in human newborns: handedness and sex-related differences.

Grasp reflex and its asymmetry was studied in relation to pH of the umbilical blood in human newborns, to examine whether the degree of acidity in fetal blood (birth stress) is associated with cerebral laterality. Low pH values were considered as an index for birth stress. Grasp-reflex strength was found to be directly related to pH in total sample. There were sex-related differences. Namely, this correlation was true only for female newborns, not for males. Right minus left grasp-reflex strength linearly increased with pH, i.e., low pH values were associated with left-hand dominance, but only in males. The grasp-reflex asymmetry was not related to pH in females. It was concluded that blood pH may be associated with motor asymmetry and motor development in human newborns, but show sex-related differences; female brain seemed to be more sensitive to pH changes than male brain. The results partly supported the Bakan's hypothesis that birth stress may be associated with left-handedness.

Dominance, Cerebral↗
PubMed1993

An enzymatic method for zinc determination in serum.

In this study, serum Zn(2+) content was determined by a new enzymatic method. The method depends on the reactivation of apocarbonic anhydrase proportional to the Zn(2+) content of the sample. Carbonic anhydrase was purified from bovine erythrocytes by affinity chromatography. The Zn(2+) in its structure was removed by dialysis against pyridine 2,6-dicarboxylic acid, resulting in a pure apoenzyme with a yield of 100%. The activity of the enzyme was determined by its esterase effect on 4-nitrophenyl acetate. Zn(2+) levels were determined in the serum samples obtained from 100 healthy subjects, 10 patients with cirrhosis, 12 diabetic patients and 15 patients with chronic renal failure by this enzymatic method and by atomic absorption for comparison. There was a good correlation between the two methods in all patients and controls and intraassay CV% was 2.4 and 4.2 for enzymatic and atomic absorption methods, respectively and interassay CV% as 3.9 and 6.1 respectively.

Animals↗
PubMed1992

Relationship of serum zinc levels to hand preference, skull length and serum gonadal hormone levels in right-handed young adults.

The association between serum zinc (Zn) level and the degree of hand preference was studied in right-handed young adults. Hand preference was scored by the Waterloo Handedness Questionnaire. Serum Zn level was determined by the flow injection analysis-atomic absorption technique. Zinc was found to be positively linearly and significantly correlated with the degree of right hand preference in the sample of males with familial sinistrality (FS+) and FS- females with right eye and right foot preference. There was a negative linear correlation between these variables in FS+ females. Skull length showed a significant negative linear correlation with zinc in FS+ males and females, but a positive linear correlation in FS- females. In FS- females, there was a significant positive linear correlation between serum gonadal hormone binding globulin (GBG) and serum Zn levels. In FS+ males, there was a significant negative linear correlation between serum GBG and Zn levels, and a significant positive linear correlation between serum free testosterone level and serum Zn level. It was suggested that zinc may influence the degree of the right hand preference by hormonal mechanisms according to genetically established brain organization.

Adolescent↗
PubMed1991

Plasma atrial natriuretic peptide and its relation to the renin-angiotensin-aldosterone system in patients with chronic renal failure.

To determine the relationship between plasma immunoreactive atrial natriuretic peptide (i-ANP) and renin-angiotensin-aldosterone system (RAAS), plasma i-ANP, plasma renin activity (PRA) and plasma aldosterone (PA) were assayed in 29 patients (19 hypertensive and 10 normotensive) with chronic renal failure (CRF), and in 10 healthy subjects. Hypertensive patients had higher i-ANP values than normotensive patients and controls (P less than 0.05 and P less than 0.01 respectively). There was no significant correlation between plasma i-ANP and creatinine concentrations in hypertensive patients, whereas this correlation was statistically significant in normotensive patients (r = 0.70, P less than 0.01). Other positive correlations were between plasma i-ANP and systolic blood pressure in hypertensive patients (r = 0.69, P less than 0.01) and between plasma ANP and mean arterial pressure in normotensive patients (r = 0.63, P less than 0.01). There was significant negative correlation between plasma ANP and fractional sodium excretion (FENa) in hypertensive patients (r = -0.47, P less than 0.05), though there was significant positive correlation in normotensive patients (r = 0.80, P less than 0.01). Hypertensive patients, with the exception of one anuric patient and another with atrial fibrillation, had a significant negative correlation between FENa and systolic arterial blood pressure (r = 0.64, P less than 0.01). The patient group had increased PRA and PA values (P less than 0.01 and P less than 0.001 respectively) and showed positive correlation with mean arterial pressure (MAP) (r = 0.71, P less than 0.001 and r = 0.58, P less than 0.01 respectively). These results show that increased concentrations of immunoreactive ANP circulate in CRF together with activated RAAS. We demonstrate that elevated ANP cannot affect blood pressure and natriuresis in hypertensive patients with CRF, whose RAAS is activated.

Adult↗
PubMed1989

Kinetic parameters of serum and lung tissue angiotensin-converting enzyme in patients with lung cancer.

Angiotensin-converting enzyme activity and its kinetic parameters were determined in both serum and lung tissue samples obtained from 17 patients with lung cancer and 21 control subjects, regardless of ethical base. The specific activities for cancerous and normal lung tissues were 67.2 +/- 27.3 (mean +/- SD) U/g protein and 28.5 +/- 5.4 U/g protein, respectively (P less than 0.001). Serum enzyme activity, on the other hand, was found to be higher in controls (198 +/- 42 U/L) than in patients (237 +/- 68 U/L) (P less than 0.01). The effects of chloride and zinc ions, pH and temperature on the enzyme activity were investigated as kinetic parameters in both serum and tissue samples.

Chlorides↗
PubMed1988

Serum zinc and angiotensin-converting enzyme levels in patients with lung cancer.

Forty-two patients with lung cancer and 72 healthy subjects were studied in order to determine a possible relationship between serum zinc and angiotensin-converting enzyme (ACE), a peptidyl dipeptide hydrolase. Serum zinc levels were 105 +/- 21 micrograms/dl in control subjects and 50 +/- 19 micrograms/dl in patients, and angiotensin-converting enzyme activity was 296 +/- 28 U/l in the former and 240 +/- 55 U/l in the latter using hippurylglycylglycine as a substrate. The findings obtained show that the decreased levels of angiotensin-converting enzyme may be related to decreased serum zinc levels and that the primary defect may be the zinc deficiency in these patients.

Adult↗