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Biomedical subjects

A Işimer

Publications and source records attributed to A Işimer.

At least 19 recordsLinked to original sources
PubMed2003

Effect of vitamin E treatment on the oxidative damage occurring in Henoch-Schönlein purpura.

AIM: To evaluate the role of reactive oxygen molecules (ROMs) in the pathogenesis of Henoch-Schönlein purpura and the effect of vitamin E on oxidative damage. ROMs have been suggested to contribute in many pathological conditions including renal diseases and vasculitis. METHODS: The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as antioxidant enzymes were measured, and the level of malondialdehyde (MDA) as an indicator of lipid peroxidation in 27 children with Henoch-Schönlein purpura at the onset of the disease and during the remission period. The results of this study were compared with those of 11 healthy children studied as a control group. RESULTS: With regard to all the oxidative damage parameters such as SOD, GSH-Px and MDA, significant differences were detected between the patients and the control group in both the acute and remission periods. But no such differences were detected between patients with and those without renal involvement. In 15 patients receiving vitamin E treatment, oxidative damage parameters and clinical course showed no improvement despite significant increases in plasma vitamin E levels. CONCLUSION: Oxidative damage and lipid peroxidation may play an important part in the pathogenesis of Henoch-Schönlein purpura but vitamin E given after initiation of lipid peroxidation, which is the last phase of cellular damage, is of no use in breaking down the oxidative chain reactions that have already been triggered.

Adolescent↗
PubMed2001

Effects of neomycin on the development of tolerance to morphine antinociception.

The effects of neomycin on the development of tolerance to morphine antinociception were examined in mice. Because neomycin did not readly cross blood brain barrier, we examined the effects of neomycin following systemic, intracerebroventricular (i.c.v.) and intrathecal (i.t.) injections on the morphine tolerance. Daily subcutaneous (s.c.), i.c.v. and i.t. injections of morphine produced tolerance regardless of route of administration. Both i.c.v. and i.t. neomycin, which alone produced no changes in the basal tail flick latencies, significantly attenuated the development of tolerance to antinociception produced by repeated systemic morphine, while intraperitoneal (i.p.) administration of neomycin did not affect morphine tolerance. Further, i.c.v. and i.t. neomycin attenuated the development of tolerance to antinociception produced by repeated i.c.v. and i.t. morphine, respectively, which were not attenuated by systemic neomycin. This results indicate a potential role for neomycin-sensitive Ca2+ channels on the development of tolerance to the morphine antinoception.

Analgesics↗
PubMed2001

Correlation between lead exposure indicators and sister chromatid exchange (SCE) frequencies in lymphocytes from inorganic lead exposed workers.

Inorganic lead exposure was studied in 31 volunteers employed in storage battery plant. The genotoxicity of lead was measured in terms of sister chromatid exchange (SCE). Erythrocyte delta-aminolevulinic acid dehydrogenase (ALAD) activity, urinary delta-aminolevulinic acid (U-ALA), and blood lead levels (PbBs) were also determined to evaluate some possible relations between these lead exposure indicators and the observed SCE frequencies. Blood lead concentration of 36.31 microg/dl was determined as an average level in the workers. Consequently decreased ALAD activity in erythrocytes and increased U-ALA excretion was observed in statistically higher PbBs when compared with the control group. A statistically significant correlation was observed between the PbBs and SCE frequencies (p < 0.05). Moreover, the correlation between U-ALA excretion and SCE frequencies (p < 0.01) was relatively higher than the correlation between PbBs and SCE frequencies. These results might indicate a possible mechanism of ALA mediation in the genotoxic effects of lead.

Adult↗
PubMed2001

Oxidative stress and nitric oxide related parameters in type II diabetes mellitus: effects of glycemic control.

OBJECTIVES: The aim of this study is to investigate the status of oxidative stress and nitric oxide related parameters in type II diabetes mellitus (DM) patients in which heart disease, atherosclerosis, retinopathy, and nephropathy commonly occur, and also to determine the effect of glycemic control on these parameters. DESIGN AND METHODS: Erythrocyte copper zinc-superoxide dismutase (CuZn-SOD), erythrocyte and plasma selenium dependent glutathione peroxidase (Se-GPx), erythrocyte catalase (CAT) activities, erythrocyte and plasma thiobarbituric acid reactive substances (TBARS) levels; nitrite/nitrate (NO(2)(-)/NO(3)(-)), cyclic guanosine monophosphate (cGMP) and nitrotyrosine levels in plasma of type II DM patients were measured. RESULTS: Erythrocyte CuZn-SOD activities in type II DM were significantly higher than those of the control subjects (p < 0.05). TBARS levels in type II DM were significantly higher than the control subjects (p < 0.001). Plasma NO(2)(-)/NO(3)(-) levels in type II DM patients both during poor glycemic control and after three months of oral antidiabetic treatment were significantly higher than those of the control subjects (p < 0.001). Plasma cGMP levels in type II DM patients during poor glycemic control were significantly lower than those of control subjects (p < 0.001). CONCLUSION: These results indicate that oxidative status and nitric oxide metabolism are affected in type II DM patients. We found high CuZn-SOD activity in type II DM patients. This increased activity could not protect the patients against the reactive oxygen species (ROS), since lipid peroxidation (defined by erythrocyte and plasma TBARS levels) still occurs in DM patients. After the therapy with oral antidiabetic agents for three months, erythrocyte SE-GPx and CAT activities were found to be decreased below the control values. Our results suggested that the low cGMP levels in the study may be a good marker of endothelium dysfunction in DM.

Adult↗
PubMed2000

Clarithromycin targeting to lung: characterization, size distribution and in vivo evaluation of the human serum albumin microspheres.

Microspheres of clarithromycin have been prepared from human serum albumin using the emulsion polymerization technique. Albumin microspheres containing the active substance were injected into the tail vein of mice. Mice were sacrificed at intervals and microspheres collected from lungs and livers. The clarithromycin amount in microspheres was determined by reversed phase high performance liquid chromatographic (HPLC) method from the mice organs. Morphological and histopathological observations were also reported. The microsphere accumulation began at 10 min, and increased gradually until 6 h, then a decrease was observed. The microspheres were still present after 24 h. In the liver sample, no microsphere accumulation was observed at any time.

Albumins↗
PubMed2000

Improvement of water solubility and in vitro dissolution rate of gliclazide by complexation with beta-cyclodextrin.

Inclusion complexes of gliclazide with beta-cyclodextrin were prepared using different two methods: neutralization and recrysstalization. Host-guest interactions were studied in the solid state by X-ray diffractometry and infrared spectroscopy. The stability constant between gliclazide and beta-cyclodextrin was calculated from the phase solubility diagram. It was found that the neutralization technique and a solid complex of gliclazide with beta-cyclodextrin in a molar ratio of 1.5:1 could be used to prepare the amorphous state of drug inclusion complexes. The dissolution rates of gliclazide from the inclusion complex made by neutralization was much faster than the pure drug, physical mixture of drug and cyclodextrin, recyristalization system and also comparable to the data reported in literature. Results of this report indicate that beta-cyclodextrin could be useful for the solid gliclazide formulations as it may results in a more rapid and uniform release of the drug.

Cyclodextrins↗
PubMed2000

Effects of agmatine on ethanol withdrawal syndrome in rats.

Effects of agmatine, which is an endogenous polyamine metabolite formed by decarboxylation of L-arginine, have been investigated on the ethanol withdrawal syndrome in rats. Adult male Wistar rats were used in the study. Ethanol (7.2% v/v) was given to the rats by a liquid diet for 21 days. Agmatine (20, 40, 80 and 160 mg/kg) and saline were injected to rats intraperitoneally 30 min before ethanol withdrawal testing. After 30th min, 2nd and 6th h of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs which included locomotor hyperactivity, agitation, stereotyped behavior, wet dog shakes and tremor were recorded or rated. A second series of injections was given at 6 h after the first one, and subjects were then tested for audiogenic seizures. Agmatine caused dose-dependent and significant inhibitory effects on stereotyped behaviors, wet dog shakes and tremors during the observation period. It did not cause any significant change in motor coordination of naive (not ethanol-dependent) rats. Our results suggest that agmatine attenuates withdrawal syndrome in ethanol-dependent rats; thus, this drug may be beneficial in the treatment of ethanol dependence.

Agmatine↗
PubMed1999

In vitro corrosion behaviour and microhardness of high-copper amalgams with platinum and indium.

Samples prepared from Luxalloy, GS-80, Permite-C and Logic and polished after 24 h by traditional methods were stored in polypropylene tubes containing phosphate-buffered saline solutions (pH 3.5 and 6.5) and distilled water. The amounts of mercury, silver, tin, copper, zinc, platinum and indium in the test solutions were determined at the first, second, eighth, 52nd and 78th week by atomic absorption spectrometry. At the end of the eighth week the amalgam samples were removed from solutions and evaluated by Rockwell Super Scial Microhardness tester. Statistically significant low amounts of metal ions were measured for Permite-C containing indium and Logic containing platinum. The microhardness test results showed that there were statistically significant increases in the microhardness of Permite-C and Logic. As a result it was shown that the amalgam samples were affected from corrosion conditions to different degrees. Sample of the Logic group that was stored in distilled water, showed smoother surface properties than other amalgam samples containing high copper. However, it was observed that samples of Permite-C group had the smoothest surface properties.

Analysis of Variance↗
PubMed1999

Dihydropteridine reductase activity and neopterin levels in leukemias and lymphomas: is there any correlation between these two parameters?

Urinary neopterin levels, blood dihydropteridine reductase activity as well as other frequently used clinical parameters were evaluated in 110 patients suffering from various types of lymphomas and leukemias. Among them neopterin was detected as the most sensitive marker representing the severity of malignancy (p<0.00001). All patients with active diseases had significantly raised urinary neopterin levels compared to those in remission and healthy controls. Of 69 patients with active disease 66 (96%) were above the upper limit seen in healthy subjects. In addition, the highest neopterin excretion was found in patients with active chronic myeloid leukemia (1469+/-479 micromol/mol creatinine n=16). In contrast, only 1 of 41 patients in stable responsive disease and remission (2.4%) had increased urinary neopterin levels above the upper limit. Dihydropteridine reductase (DHPR) activities were also detected in all patients and control groups. In active disease slightly reduced (DHPR) activities were evident (3.42+/-0.37 for controls, 2.92+/-0.39 in active disease and 3.28+/-0.42 nmol red cytochrome C/min/5 mm diameter disc in remission patients). However in patients under medication this was strengthened. This data also suggest that DHPR activity can be effected by chemotherapy. The results of the present study support the fact that urinary neopterin levels may be an useful and reliable early prognostic marker for neoplasia when used together with other prognostic indicators. Our data also suggest that reductions in DHPR activities may also be an underlying cause for the neurological disorders that are commonly seen in patients with haematological malignancies.

Biomarkers, Tumor↗
PubMed1998

Antioxidative metabolism in Down syndrome.

Down syndrome is the most common cause of mental retardation, affecting 1 in 700-800 liveborn infants. Although numerous biochemical abnormalities accompanying the syndrome have not yet been completely clarified, the antioxidant defense system enzymes have shown to be altered due to increased gene dosage on chromosome 21 and overproduction of superoxide dismutase (SOD-1 or Cu/Zn SOD). The purpose of this study was to investigate the activities of SOD-1 and glutathione peroxidase (GSH-Px) enzymes and the levels of their cofactors zinc (Zn), copper (Cu) and selenium (Se) in plasma of 20 Down syndrome patients. In comparison with age and sex-matched controls (n = 15), plasma GSH-Px, SOD, and Cu levels were significantly decreased in the patient group, but Zn and Se concentrations remained unchanged.

Adolescent↗
PubMed1997

Analgesic effects of amlodipine and its interaction with morphine and ketorolac-induced analgesia.

1. The antinociceptive effects of amlodipine, administered subcutaneously (s.c.), intracerebroventricularly (i.c.v.) and intrathecally (i.t.) were examined with the acetic acid writhing and tail-flick tests in mice. Amlodipine was also tested in combination with morphine and ketorolac. Isobolographic analyses were used to define the nature of functional interactions between amlodipine and morphine or ketorolac. 2. The s.c. (0.1, 1.25, 2.5, 5 and 10 mg/kg), i.c.v. (2.5, 5, 10 and 20 micrograms/mice) and i.t. (2.5, 5, 10 and 20 micrograms/mice) administration of amlodipine exhibited a dose-dependent antinociceptive effect in the writhing test but had no effect on the tail-flick latency. Isobolographic analyses revealed an additive interaction between amlodipine and morphine or ketorolac in the writhing test. 3. These results suggest that amlodipine induces antinociception and increases antinociceptive action of morphine and ketorolac, possibly through a decrease in cellular calcium availability.

Acetic Acid↗
PubMed1997

Aluminum in enteral nutrition formulas and parenteral solutions.

BACKGROUND: To examine the aluminum content of several commercially available enteral nutrition formulas and parenteral solutions. METHODS: Twelve enteral nutrition formulas and 10 parenteral solutions were commonly used in routine clinical care of patients and obtained from different medical companies in Turkey. The aluminum contents were determined by electrothermal atomic absorption spectrophotometry. RESULTS: We found that aluminum concentration in the enteral nutrition formulas and the parenteral solutions to range from 87.6 to 961.2 ng/mL and 58.4 to 1232.0 ng/mL, respectively. CONCLUSIONS: Careful clinical and biochemical monitoring are warranted to determine whether it will be necessary to eliminate aluminum contamination of enteral and parenteral preparations used in patients, particularly infants, with reduced kidney function who may be at risk for aluminum intoxication.

Albumins↗
PubMed1996

Four novel cycloartane glycosides from Astragalus oleifolius.

Four novel cycloartane-type triterpene glycosides, macrophyllosaponins A-D (1-4) were isolated from the roots of Astragalus oleifolius. By means of chemical (acetylation, alkaline hydrolysis) and spectroscopic methods (IR, 1D- and 2D-NMR, FABMS), their structures were established as 3-O-alpha-L-rhamnopyranosyl-24-O-(4"-O-acetyl)-beta-D-xylopyranosyl-1 alpha,3 beta,7 beta,24(S), 25-pentahydroxycycloartane (1), 3-O-alpha-L-rhamnopyranosyl-24-O-beta-D-xylopyranosyl-1 alpha,3 beta, 7 beta,24(S), 25-pentahydroxycycloartane (2), 3-O-alpha-L-rhamnopyranosyl-25-O-beta-D-glucoyranosyl-1 alpha, 3 beta,7 beta,24(S),25-pentahydroxycycloartane (3), and 3-O-alpha-L-rhamnopyranosyl-24-O-(2-O-beta-D-xylopyranosyl) -beta-D-xylopyranosyl-1 alpha,3 beta,7 beta,24(S), 25-pentahydroxycycloartane (4).

Carbohydrate Sequence↗
PubMed1996

Serum and pleural fluid selenium, copper, zinc, and magnesium levels in malignant and nonmalignant pleural diseases.

In the present study, selenium (Se), copper (Cu), zinc (Zn), and magnesium (Mg) levels in serum and pleural fluid from patients with malignant and nonmalignant pleural diseases were measured and compared with serum concentrations in healthy subjects. Serum/pleural fluid ratios were also calculated for each element. The purpose of this study was to evaluate the diagnostic value of trace metals, especially Se, in neoplastic and nonneoplastic pleural diseases. Serum Cu and Mg levels were significantly higher in both malignant and nonmalignant groups of patients when compared with control subjects (p < 0.05). However, serum levels of these elements did not show a significant difference between malignant and nonmalignant cases (p > 0.05). The serum/pleural fluid ratio of Zn was significantly lower in patients with malignant effusions than in benign conditions (p = 0.05). Serum and pleural fluid Se, Cu, Zn and Mg levels were not significantly different between the two groups (p > 0.05). Thus, Se, Cu, Zn, and Mg seem to have no diagnostic value for distinguishing malignant from nonmalignant effusions.

Adult↗
PubMed1995

Aluminum content of infant formulas used in Turkey.

In the past few years, there has been an upsurge of interest in aluminum (Al) and human health. The well-recognized manifestations of systemic Al toxicity include fracturing osteomalacia, dialysis encephalopathy, and microcytic hypochromic anemia. The role of Al in causing childhood diseases is also becoming clearer, but the safe plasma level still remains to be determined in newborns, especially in premature newborns, implying that it should be kept low. Premature infants receiving iv fluid therapy show evidence of Al loading. Additionally, the infant-feeding mixtures, especially the soy-based infant formulas, tested may be a significant additional source of Al in the diet of infants with low birthweights, and in infants and in young children with impaired renal function. Careful clinical and biochemical monitoring is warranted to determine whether it will be necessary to eliminate Al contamination of both oral and parenteral preparations used in infants and children who may be at risk for Al intoxication. In this present study, the Al content of infant feeds was measured by electrothermal atomic absorption spectrophotometry, and also compared with those of breast milk, cow's milk, milk powder, and some starches that are commonly used for preparation of infant feed in Turkey. Our results show that Al content of commercially available powdered infant formulas, most of which are imported from Europe, ranged from 1.211 to 10.925 micrograms/g. The mean value was higher than that of breast milk. It was also found that the Al content of cow's milk in various containers was higher than that of breast milk. The highest Al level among cow's milk samples was in the aluminized carton box.

Aluminum↗
PubMed1995

Plasma trace element, plasma glutathione peroxidase, and superoxide dismutase levels in epileptic children receiving antiepileptic drug therapy.

Some antiepileptic drugs (AEDs) may alter trace element metabolism and free radical scavenging enzyme activities in humans and experimental animals. We investigated the effect of long-term AED therapy on copper (Cu), zinc (Zn), manganese (Mn), selenium (Se), magnesium (Mg), glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD) in the plasma in children with epilepsy. During treatment with valproate (VPA) or carbamazepine (CBZ) monotherapy plasma Cu, Zn, Mn, Se, and Mg concentrations of patients were not statistically different from those of control subjects. The level of serum VPA weakly correlated with the increase in plasma Zn level. Recent studies suggest that membrane lipid peroxidation may be causally involved in some forms of epilepsies, and the decreased free radical scavenging enzyme activity is believed to cause the increased risk of an idiosyncratic drug reaction encountered in the management of epilepsy. Because GSH-PX and SOD are the most important members of antioxidant defense mechanisms, we quantitated the activities of these enzymes in plasma of children with epilepsy receiving VPA or CBZ. Only plasma GSH-PX activities in VPA group were higher than those of the control group, and the difference was statistically significant.

Adolescent↗