Biomedical subjects

B Turan

Publications and source records attributed to B Turan.

At least 19 recordsLinked to original sources

PubMed2003

Sympathetic skin response and R-R interval variation in cases with rheumatoid arthritis.

To investigate the autonomic nervus system involvement in cases with rheumatoid arthritis (RA) by assesing sympathetic skin response (SSR) and R-R interval variation (RRIV), 14 healthy women and 10 women with RA, all of them without clinic dysautonomies were examined. SSR's were recorded palmar surface of both hands and soles of both feet, after stimulating median and tibial nerves individually. RRIV's were assessed at rest and during six deep breathing in one minute with electrodes placed on dorsal surfaces of both hands. SSR could not be obtained from lower extremities of one case with RA. We could not find any significant difference between two groups in terms of SSR latencies. RRIV values obtained during deep breathing to those recorded at rest (D%/R%) was found to be significantly lower in RA cases than healthy controls. RRIV values increased with deep breathing in healthy subjects, while they decreased in 50% of the RA cases. We conclude that assessment of SSR and RRIV are valuble methods for revelation of subclinical autonomic involvement in cases with RA.

Adult↗

PubMed2003

Vegetable oils used as vitamin E vehicle affect the electrical activity of the rat heart.

The aim of this study is to define the possible effects of vegetable oils used as vitamin E vehicle on the electrical activity of the rat heart. To test the possible effects of vitamin E vehicles we studied the effect of i.p. injected corn oil, hazelnut oil or peanut oil on the action potential parameters recorded in both papillary and left atrial muscle strips. Four experimental groups were used. The control group was injected (i.p.) with distilled water, while the three remaining groups received injections of corn oil, hazelnut oil, or peanut oil for five weeks (in a dose of 0.4 ml/kg/day--minimum amount of oil in which vitamin E could be dissolved). We used borosilicated (15-20 megaohms) capillary electrodes and intracellular action potentials (AP) were recorded in isolated papillary and left atrium muscle strips. While administration of three different types of vegetable oil had no significant effect on AP parameters of papillary muscle, they significantly prolonged the repolarization phase of AP in atrial strips. These results show that vegetable oils used as vitamin E vehicles may alter the electrical activity of the heart in a tissue-dependent manner. The present data indicate that the possible effect of vegetable oil vehicles should be kept in mind while evaluating the possible effects of in vivo vitamin E administration.

Action Potentials↗

PubMed2002

The role of coping with disease in adherence to treatment regimen and disease control in type 1 and insulin treated type 2 diabetes mellitus.

BACKGROUND: Coping is defined as the behavioral and cognitive efforts used in an attempt to deal with stressful events. The objective of this study was to explore the relationship between coping with diabetes and the following outcome variables in type 1 and insulin treated type 2 diabetes mellitus: glycemic control, microangiopathic complications, adherence to self monitoring of blood glucose, adherence to insulin injections, and adherence to diet. METHODS: Subjects were 196 insulin treated adult diabetes patients visiting an outpatient clinic at a government university hospital in Istanbul, Turkey. Coping with disease was measured with the Turkish version of the Diabetes Coping Measure and adherence to treatment regimen was measured with a questionnaire adapted from the subscales of the Summary of Diabetes Self-Care Activities Questionnaire. Data on patients' HbA(1c) levels and severity of microangiopathic complications were obtained from their medical records. RESULTS: Partial correlations controlling for background variables suggested that coping was a good predictor of outcome for both type 1 and insulin treated type 2 diabetes mellitus. These associations were more pronounced for type 1 patients when compared to type 2 patients. Regressing the outcome variables on the two second-order coping factors (obtained by a factor analysis) also supported the hypothesis that coping is an important construct in explaining the outcome variables. Finally, the effect of coping on HbA(1c) was only partially mediated by adherence. CONCLUSION: Coping with diabetes-related issues is an important factor in both types of diabetes, with type 1 patients showing slightly stronger associations. Therefore, training and education programs for diabetic adults might benefit from including a component that is aimed at improving coping with issues specific to diabetes.

Adaptation, Psychological↗

PubMed2001

Adenosine triphosphate alters the selenite-induced contracture and negative inotropic effect on cardiac muscle contractions.

Selenium is known to play an important role in the physiology of many different cell types and extracellular application of selenite causes cellular dysfunction in many different types of tissues. In a previous study, we have shown that in rat ventricles, sodium selenite (> or = 1 mM) caused an increase in the resting tension and a decrease in contractile force, in a time-dependent manner. In the present study, we have shown that sodium selenite caused a contracture state both in Langendorff perfused hearts and isolated papillary muscles. We also showed that the application of extracellular ATP (0.1 mM) markedly reduced this detrimental effect of sodium selenite on ventricular contraction in Langendorff perfused hearts and delayed it in isolated papillary muscle preparations. In contrast, isoproterenol (0.1 microM) did not seem to influence this action of sodium selenite in papillary muscle preparations. Possible reasons for this protective effect of ATP to selenite-induced contracture are also discussed.

Adenosine Triphosphate↗

PubMed2001

A comparative study on effect of dietary selenium and vitamin E on some antioxidant enzyme activities of liver and brain tissues.

Since selenium and vitamin E have been increasingly recognized as an essential element in biology and medicine, current research activities in the field of human medicine and nutrition are devoted to the possibilities of using these antioxidants for the prevention or treatment of many diseases. The present study was aimed at investigating and comparing the effects of dietary antioxidants on glutathione reductase and glutathione peroxidase activities as well as free and protein-bound sulfhydryl contents of rat liver and brain tissues. For 12-14 wk, both sex of weanling rats were fed a standardized selenium-deficient and vitamin E-deficient diet, a selenium-excess diet, or a control diet. It is observed that glutathione reductase and glutathione peroxidase activities of both tissues of the rats fed with a selenium-deficient or excess diet were significantly lower than the values of the control group. It is also shown that free and bound sulfhydryl concentrations of these tissues of both experimental groups were significantly lower than the control group. The percentage of glutathione reductase and glutathione peroxidase activities of the deficient group with respect to the control were 50% and 47% in liver and 66% and 61% in the brain, respectively; while these values in excess group were 51% and 69% in liver and 55% and 80% in brain, respectively. Free sulfhydryl contents of the tissues in both experimental groups showed a parallel decrease. Furthermore, the decrease in protein-bound sulfhydryl values of brain tissues were more pronounced than the values found for liver. It seems that not only liver but also the brain is an important target organ to the alteration in antioxidant system through either a deficiency of both selenium and vitamin E or an excess of selenium alone in the diet.

Animal Nutritional Physiological Phenomena↗

PubMed2000

A biomechanical and spectroscopic study of bone from rats with selenium deficiency and toxicity.

Selenium, being an essential mineral in the mammalian diet, is important in providing protection against oxidative damage. Numerous in vitro studies of selenium compounds reveal a very high correlation between catalytic activity of selenium compounds and toxicity. The present study was designed to investigate the effects of dietary selenium on the biomechanical properties of bone. New born rats of both sexes were fed with either a control, or a selenium- and vitamin E-deficient, or a selenium-excess and vitamin E-adequate diet. We obtained the stiffness (modulus of elasticity) of bones (femur and tibia) by tensile test for all groups considered. Both the deficient and the excess groups have decreased biomechanical strength with respect to the control group. To support our biomechanical results for both experimental groups, X-ray diffraction analysis and FTIR spectroscopic study were performed on the femurs and tibiae. The X-ray diffraction analysis showed that the intensities of the peak observed at around 2theta degrees = 31.820, in the control femur and tibia are stronger than the intensities of the corresponding peak of two experimental groups. In FTIR spectroscopy, the disappearance and/or reduction of the intensities of some carbonate bands in the two experimental groups indicate that there is a decrease in crystallinity and mineral contents which, together with X-ray diffraction analysis, correlate very well with the biomechanical data.

Animals↗

PubMed2000

Dietary selenium and vitamin E intakes alter beta-adrenergic response of L-type Ca-current and beta-adrenoceptor-adenylate cyclase coupling in rat heart.

Previously we have shown that both insufficient (combined with vitamin E deficiency) and excess intake of selenium (Se) impairs isoproterenol (ISO)-induced contractions of rat papillary muscle. In the present study, we used patch-clamp and biochemical techniques to investigate mechanisms of this effect in rats fed a Se- and vitamin E-deficient, a Se-excess or a normal diet. Whole-cell configuration of patch-clamp technique was used to investigate L-type Ca(2+) currents (I(Ca,L)) and their regulation by beta-adrenergic receptor stimulation in enzymatically isolated single rat ventricular myocytes. Alteration of Se and vitamin E intake did not affect peak I(Ca,L), but the threshold potential of activation was significantly different among groups. Maximal I(Ca,L) responses to ISO were depressed in both experimental groups, but the EC(50) values were not affected. In the Se-deficient group, basal, ISO- or forskolin-induced adenylate cyclase (AC) activity, measured in cardiac membrane preparations, was reduced when compared to the control, whereas 5' guanylyimidodphosphate (GppNHp) stimulated activity was unaffected. Decreased beta-adrenoceptor density and reduced GppNHp-induced affinity shift in ISO binding were also observed in the deficient group. No such differences were present in the excess group. These results suggest that combined Se and vitamin E deficiency interferes with beta-adrenoceptor-AC coupling, whereas excess intake of Se does not affect it. Thus, in the deficient group, the impairment of I(Ca) responses to ISO may be a result of a defect in beta-adrenoceptor-AC pathway. Impairment of I(Ca) response in the excess group, however, appears to have a different underlying mechanism.

Adenylyl Cyclases↗

PubMed2000

Disulfonic stilbene prevents selenite-induced cataract in rat pup lens.

It is known that the subcutaneous injection of a single dose of sodium selenite into suckling rats results in the development of large nuclear opacities. The intracellular transport of selenite in various cells, except lens cells, occurs via the Cl/HCO3 exchanger. The aim of the present study is to investigate the possible role of the anion-exchange inhibitor, disulfonic stilbene (SITS), in the selenite-induced catarogenesis in the rat pups. Wistar albino rats (8-10 d old) were separated into three groups: one control and two experimental. The first experimental group was injected subcutaneously with a single dose of 30 nmol sodium selenite/g body weight. The second experimental group was injected with a single dose of 10 nmol SITS/g body weight 15 min before the same dose selenite injection. The control group did not have any injections. The stage of cataract development was examined on d 7 postinjection with slit-lamp photographs. In SITS pretreated group, all eyes remained transparent (considered as stage 0), whereas in the selenite-injected group, the animals did have different stage of nuclear cataract; 8 animals have stage 5, 10 animals have stage 4, and 4 animals have stage 3. A pretreatment of SITS completely prevented cataract formation of the selenite-induced cataract model in rat pups.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗

PubMed2000

Prevention of selenite-induced opacification and biochemical changes in the rat pup lens through amiloride pretreatment.

PURPOSE: To determine the effects of amiloride on selenite-induced cataracts, to identify this agent's role as an anti-oxidant, and to study related effects on ion levels in the rat lens. METHODS: Wistar albino rat pups were assigned to one of three groups, one control and two experimental. The first experimental group (Group 1; n = 22) received a subcutaneous injection of sodium selenite (30 nmol/g body weight) on postpartum day 10. The second experimental group (Group 2; n = 21) received a subcutaneous injection of amiloride (1 nmol/g body weight) 15 minutes before the sodium selenite injection. The control group (n = 22) received no injection. The pups in each group were observed during three weeks after the injection date. At the end of this period, the stage of cataract development was identified by comparison with slit lamp photographs and then the pups were sacrificed and their lenses were removed intracapsularly using a posterior approach. Cation analysis was carried out and glutathione and malondialdehyde levels were measured for each group. RESULTS: Cataract stage in Group 1 was significantly higher than Group 2. Mean cataract stages in Groups 1 and 2 were 3.8+/-0.12 and 1.6+/-0.25 respectively. None of the control animals developed cataracts. Amiloride-pretreated group contained significantly higher glutathione levels than Group 1. The level of malondialdehyde in Group 1 lenses was approximately twice that in the lenses of the Group 2 amiloride+selenite-treated animals. The Ca(2+) level was significantly higher in Group 1 lenses compared to the amiloride-pretreated rats, but there was no significant difference between Groups 1 and 2 with regard to Na(+) and K(+) levels. CONCLUSION: Amiloride was very effective in preventing cataract formation in the selenite-induced cataract model. This protective effect of amiloride was accompanied by higher glutathione levels and lower malondialdehyde levels in the rat pups' lenses compared to levels in animals that received selenite alone. These results suggest an anti-oxidant role for this agent, in addition to its effects on lens ion homeostasis.

Amiloride↗

PubMed1999

Cardiac dysfunction induced by low and high diet antioxidant levels comparing selenium and vitamin E in rats.

The present study was designed to investigate and compare the effects of dietary antioxidants on the mechanical characteristics of the rat heart. Both sex weanling rats were fed for 12 to 14 weeks a standardized selenium (Se)- and vitamin E-deficient diet, a Se-excess diet, or a control diet. Deficiency or toxicity of Se was verified by direct (tissue Se analysis and histopathological investigations) methods. The hearts of both experimental groups revealed some alterations in contractile performance with increased heart rate and coronary perfusion pressure. The average peak contractile force of the electrically stimulated papillary muscle measured in both experimental groups was not significantly different from the control values. When expressed as a percentage, the maximal increase in the peak contractile force of papillary muscle (PCF) that was obtained with 100 nM isoproterenol, respectively, was less in both experimental groups (26% in PCF of deficient group; 34% in PCF of rich group) than in the control group (80% in PCF). A decreased stimulation of contractile force of papillary muscle strips by a beta-adrenergic agonist seems to be in agreement with possible alterations in the response to inotropic agents due to a modification of the receptor function.

Animals↗

PubMed1999

Normative data of sympathetic skin response and RR interval variation in Turkish children.

Sympathetic skin response (SSR) and RR interval variation (RRIV) are used commonly for the assessment of sympathetic and parasympathetic nervous system function, respectively. We determined the normal values of SSR and RRIV in 23 (14 females, nine males) Turkish children aged 5 to 14 (mean 9.86, SD 2.48) years. SSR was recorded on the hands and feet during the electrical stimulation of both median and posterior tibial nerves, respectively. Similar response was elicited on both feet during the stimulation of the right median nerve. RRIV testing was performed during rest on the supine position and deep inspiration at a frequency of 6 times/min. The SSR was elicited in all children. The mean SSR latencies recorded on the feet during the stimulation of median or posterior tibial nerve were significantly more prolonged than those recorded at the hands (P < 0.001). There was no significant difference between the mean latencies of SSR recorded at the ipsilateral and contralateral palms or soles. The mean latencies recorded at the sole during stimulation of the median nerve were not significantly different compared to those that recorded at the sole during the posterior tibial nerve (P > 0.05). The SSR amplitudes were not assessed because of great variability and rapid habituation. The mean RRIV (46.54+/-11.29%) during deep breathing was significantly increased as compared to that (35.90+/-10.63%) during rest (P < 0.003). As a result, SSR and RRIV are preferred non-invasive tests for evaluation of autonomic nervous system in children. The SSR is useful and reliable if it is obtained in the optimum technical conditions. Further research is necessary to establish strict criteria for abnormality.

Adolescent↗

PubMed1999

The influence of wrist thickness on amplitudes of sensory nerve action potentials.

Normal values of sensory nerve action potential (SNAP) amplitudes vary widely. There are many factors which can influence the amplitude of the SNAP, such as the type of recording techniques, temperature, distance between recording electrodes, skin impedance, etc. In this study, we investigated the correlation between wrist thickness (palmar to dorsum diameter) and amplitudes of the SNAP of median and ulnar nerves of 20 healthy subjects. Ring electrodes were placed on the second and the fifth fingers and a surface block electrode was placed at the wrist between the flexor carpi radialis and the palmaris longus tendon and just radial to the flexor carpi ulnaris tendon, for testing the median and ulnar nerves, respectively. Both orthodromic and antidromic techniques were used. Depending on the technique, either ring or surface block electrodes could be the stimulating or the recording electrodes. By supramaximal intensity stimulation, the amplitude of the SNAP was measured from peak to peak. The results revealed that SNAP amplitudes and wrist thickness are reversely correlated, with statistical significance (p < or = 0.005) by using the antidromic technique. The influence of wrist thickness on SNAP amplitudes should be recognized when performing an electrodiagnostic study to determine axonal degeneration by using the SNAP amplitude parameter.

Action Potentials↗

PubMed1999

The effects of long-term heparin application on ACh-induced isolated ileum contractility and structure.

The present study was designed to investigate the side-effects of long-term (one and two months), overdoses (1000 and 2000 IU/kg/day) heparin (Liquamine) applications on the isolated ileum contractility and the histopathological alterations in the ileal tissues. The histopathology of tissues was investigated by using light microscopy. Isolated ileum contractility was measured by using the conventional organ bath system with standard and Ca-free Tyrode perfusion solutions. Ileum preparations were initially contracted with ACh maximally and these contraction amplitudes were given as% values. The average amplitude of these contractions of all experimental groups were found to be increased significantly with respect to control group, in both perfusion solutions. Under light microscopy, in the preparations treated with 1000 IU/kg/day heparin, we have observed edema in the ileal mucosa and neutrophil infiltration in the villi. In addition, the glandular tissue degeneration was also seen in 2000 IU/kg@day group. We can suggest that most probably, the binding of heparin to the receptor on the cell membrane results Ca-release.

Acetylcholine↗

PubMed1998

The effect of altered selenium and vitamin E nutritional status on learning and memory of third-generation rats.

It has been proposed that selenium (Se) and Vitamin E (Vit E) are involved synergistically in protection of cell membrane lipids from peroxidation. However, little is known about the effect of both deficiencies of Se and Vit E and toxic status of those antioxidants on the peroxidation potentiality of the brain. We aimed to study the effects of both Se and Vit E inadequate diet and Se rich diet on the learning and memory processes of third-generation young rats. Their ancestors were also fed by the same diets starting from their births. To test the learning and memory, the rats aged 60 days were trained by using automated two ways active avoidance shuttle box. The acquisition tests were terminated with training the rat from each group to be 25 trials per day during three days. Ten days after the last acquisition test, the retention test was performed and the acquisition of the conditioned avoidance responses (CAR) of the rats were evaluated. It is demonstrated that the CAR of all rats from three groups showed a significant increase in three consecutive days while the differences observed in CAR of same sessions was not significantly different among three groups. The memory process of these young rats also was not affected significantly by two types of diets. Under the light of our results one can suggest that, in the case of alterations in antioxidant defense status, the learning and the memory mechanisms seems to be not affected. Further researches are needed to be able to explain the possible role of oxidative stress on the mechanisms of learning and memory.

Animals↗

PubMed1998

The effect of selenium and vitamin E on microvascular permeability of rat organs.

The effects of dietary sodium selenite and vitamin E on the microvascular permeability of rat organs such as heart, brain, kidney, liver and eye were investigated by using the Evans blue leakage method. Combined deficiency of selenium and vitamin E caused an increase in the permeability of the heart and eye with respect to their controls while it had no considerable effect on the permeability of other organs. On the other hand, toxic levels of selenium (4.2 mg/kg) in diet decreased the permeabilities in kidney, liver, and eye whereas this parameter of brain increased in the same animal group. These results suggested that low or high sodium selenite and vitamin E contents in diet could alter the microvascular permeability of different organs in different manners. It might be important to give reasonable explanations for the pathophysiology of some diseases that are characterized with organ damage and/or disfunction originated from selenium deficiency or toxicity.

Animals↗

PubMed1998

Tissue and concentration-dependent effects of sodium selenite on muscle contraction.

In this study, we demonstrated that sodium selenite with high doses (> or = 10(-3) M) were potent in inducing a contracture type effect on heart and smooth muscles. Selenite (Se), at a concentration of 10(-3) M, caused a contracture effect in heart preparations. Also, low Se concentrations did not have any significant effect. Although low concentrations of Se (> or = 10(-5) M) had a biphasic effects on acetylcholine (ACh) induced and spontaneous ileum contractions, 10(-3) M selenite enhanced once more a contracture effect similar to that of the heart preparations. Replacing Ca2+ concentration of the bathing solution by twofold Ca2+ or Ca2+-free did not change the effects of selenite (10(-5) M) on contractility of ileum preparations. In vascular smooth muscle, low concentration of selenite (< 10(-4)) had no significant effects on KCl, and phenylephrine-induced contractions and acetylcholine-induced endothelium-dependent relaxations of isolated rabbit aorta. However, the contractions induced by phenylephrine and the relaxations induced by acetylcholine in rabbit aorta were depressed significantly by high concentration of selenite (10(-3) M). The results obtained by selenite exposure from these three different types of tissue preparations first suggest that the high concentration of selenite exposure induces some alterations in the functions of muscles and endothelium in a tissue- and dose-dependent manner. Second, this observed irreversible type of dysfunction of tissues induced by 10(-3) M selenite is not directly dependent on the Ca2+ entrance into the cytosol, but might be induced by the increase of intracellular Ca2+ with the disturbance of Ca2+ regulation.

Acetylcholine↗

PubMed1998

Ultrasound therapy effect in carpal tunnel syndrome.

OBJECTIVE: To investigate the overall effect of repeated ultrasound treatment in carpal tunnel syndrome (CTS). DESIGN: Patient-blinded, placebo-controlled, before-after treatment trial. SETTING: University hospital PM&R department outpatient clinic and neurology department electromyography laboratory. PATIENTS: Eighteen women with diagnosis of CTS in 30 hands. INTERVENTIONS: Three groups, each with 10 cases of CTS, were randomly established. Continuous ultrasound therapy, with intensities of 1.5W/cm2 (group A), 0.8W/cm2 (group B), and 0.0W/cm2 (group C), was applied to palmar carpal tunnel area for 5 minutes, 5 days a week, for 2 weeks. OUTCOME MEASURES: Patients were evaluated clinically and electrophysiologically before and after the treatment. RESULTS: At the end of treatment, statistically significant improvement was obtained in clinical parameters in all groups: pain (p < .05), pain/paresthesia at night/day (p < .05), and frequency of awakening at night (p < .05). Although there was no statistically significant before-after difference in electrophysiologic studies, slightly decreased motor nerve conduction velocity and increased motor distal latency were noted in groups A and B, but not in group C. CONCLUSION: Ultrasound therapy in CTS was comparable to placebo ultrasound in providing symptomatic relief, and the probability of a negative effect on motor nerve conduction needs to be considered.

Adult↗

PubMed1997

Effect of dietary selenium and vitamin E on the biomechanical properties of rabbit bones.

It is generally agreed that combined deficiency of selenium and vitamin E leads to several abnormalities including Kashin-Beck disease which is an endemic and chronic degenerative osteoarthrosis. The abnormalities can be reversed by the administration of various forms of selenium and vitamin E. The present study was designed to investigate the effects of dietary selenium and vitamin E on bone tissue and on the biomechanical properties of bone. Young rabbits of both sexes were fed with either a selenium- and vitamin E-adequate diet (control group), or a selenium- and vitamin E-deficient diet or a selenium-excess diet. The selenium-deficient diet resulted in a significant decrease in plasma selenium level and the selenium-excess diet resulted in a significant increase in the plasma selenium level with respect to the corresponding control values (p < 0.05). The diets did not affect the blood cell counts considerably but erythrocyte glutathione peroxidase activity increased (decreased) relatively when the plasma selenium level increased (decreased) (p < 0.05). The light microscopic investigations of the bone tissues of the two experimental groups indicate that the findings of the present work are compatible with osteomalacia. The biomechanical properties of the bones from the three groups were determined experimentally with bending tests. Both the Se- and vitamin E-deficient diet and the Se-excess diet decreased the biomechanical strength of the bones significantly while the bones belonging to the control group always had the largest modulus of elasticity (p < 0.05).

Animals↗