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Biomedical subjects

G Sahin

Publications and source records attributed to G Sahin.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of some probable antioxidants on selenite-induced cataract formation and oxidative stress-related parameters in rats.

The effect of several natural and synthetic compounds on selenite-induced cataract was investigated in rat pups. Simultaneous determination of glutathione S-transferase (GST), selenium dependent glutathione peroxidase (Se-GPx), catalase (CAT), superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels were carried out in the lens, erythrocyte and plasma. The results showed that propolis, diclofenac, vitamin C (Vit-C) and quercetin prevented cataract formation to the extent of 70, 60, 58.4, and 40%, respectively. Standardized extract of Ginkgo biloba (Egb 761) did not affect the cataract formation. Selenite treatment caused a significant decrease in the activity of erythrocyte SOD. This was accompanied by a simultaneous increase in the levels of MDA either in lens and in plasma. A significant increase was shown in erythrocyte GST (substrate ethacrynic acid; eaa), and GPx activities and lens GST (substrate chlorodinitro benzene; cdnb) activity. Antioxidant treatment caused significant changes in enzyme activities and MDA levels. There was no effect of selenite and antioxidants on total body weight increase during the course of the study. Blood parameters did not correlate to lens parameters following selenite treatment. Our results suggest that antioxidant supplementation following selenite exposure may prevent the cataract formation and may enhance antioxidant defence of blood and lens.

Animals↗
PubMed1999

Osteoarthricular involvement of brucellosis in Turkey.

The aim of this study was to determine the rates, types, clinical features and treatment of osteoarthricular involvement of brucellosis in Turkey. In a restrospective study in adults, we investigated 238 patients diagnosed with brucellosis over a period of 6 years. A diagnosis of brucellosis was established by isolation of Brucella species in blood or by a compatible clinical picture together with a standard tube agglutination titre of > or = 1/160 of antibodies for brucellosis and/or demonstration of an at least four-fold rise in antibody titre in serum specimens taken over 2 or 3 weeks. Osteoarthricular involvement was defined by inflammatory signs in peripheral joints or by unrelieved pain at rest together with radiological alterations and/or radionuclide uptake in any deep joint. Eighty-seven patients (36.5%) had osteoarthricular involvement (58.6% female, 41.4% male), 47 (54.1%) of whom were reported to consume unpasteurised dairy products. The mean age was 32.3 +/- 16 years. Sacroiliitis was the most common involvement (n = 53, 60.9%) followed by peripheral arthritis (n = 17, 19.5%), spondylitis (n = 12, 13.8%) and bursitis (n = 5, 5.7%). During the observation period, 60 (69%) patients with osteoarthricular involvement and radiographic abnormalities. A bone scan was positive in 15 patients with no radiographic abnormalities. All patients received merely medical treatment and relapse occurred in five (5.7%) patients. Sacroiliitis has been determined as the most frequently observed type of osteoarthricular involvement in brucellosis in Turkey.

Adolescent↗
PubMed1999

The in vitro effects of new non-steroidal antiinflammatory compounds on antioxidant system of human erythrocytes.

It has been reported by our group that some benzoxazolone and benzothiazolone derivatives showed significant antinociceptive and anti-inflammatory activity [DOGRUER et al. 1997]. It has been speculated that nonsteroidal anti-inflammatory drugs (NSAIDs) can act as the free radical scavengers and possess antioxidant activity. It is also well documented that oxidative stress can play an important role in the side effects of many xenobiotics including NSAIDs. Therefore, in the present study, the effects of six of the above mentioned benzoxazolone and benzothiazolone derivatives bearing 2-pyridylaminocarbonylmetyl moiety at the position 3 (I) on the antioxidant system-related parameters of human erythrocytes have been investigated. Diclofenac and nimesulid were also tested in the same systems as the control, because they are commonly used as NSAIDs. Our results showed that these compounds made significant changes in the antioxidant system of human erythrocyte.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

In vivo effects of non-steroidal antiinflammatory drugs on oxidative stress-related parameters of human erythrocytes.

In this study, we evaluated the effects of commonly used non-steroidal anti-inflammatory drugs (NSAIDs) on oxidative stress and anti-oxidant system. Sixteen healthy volunteers and 35 patients diagnosed as one of musculoskeletal disorders were included in the study. Patients were treated with one of the three NSAIDs (i.e. naproxen, tiaprofenic acid, acemetacin) or paracetamol for 15 days. Erythrocyte glutathione S-transferase, erythrocyte and plasma glutathione peroxidase, and erythrocyte catalase (CAT) activities and plasma malondialdehyde level as lipid peroxidation index were detected in the blood samples of the patients, at the beginning of the study (0 week), after treatment for 15 days (2nd week), and at the end of 1 week-washout period (3rd week). The most affected enzyme by NSAIDs was erythrocyte catalase, which tended to increase at the end of 2 weeks treatment, and decrease at the end of 1 week-washout period. In the groups treated with acemetacin, naproxen and tiaprofenic acid, plasma malondialdehyde levels were decreased at some extent, but at the end of washout period a rebound increase was observed in acemetacin group. Our results suggest that NSAIDs have different influences on oxidative stress and anti-oxidant system related parameters. These effects seem to be related with the mechanisms of some of the adverse effects, which are not well understood yet. Further studies with larger groups are needed to illuminate the relationship between adverse effects of NSAIDs and the effects of these drugs on anti-oxidant system, and to clarify their mechanisms of therapeutic action, as well.

Adult↗
PubMed1999

Aluminum content of vaccines used in Turkey.

Aluminum salts have been used in the preparation of a number of vaccines, toxoids, and allergen injectants as an adjuvant for many years. Although aluminum allergy is rare, there are many reported cases caused by aluminum-precipitated vaccines or hyposensitization therapy. Therefore, determination of the aluminum content of these vaccines is necessary information regarding adverse reactions related to these vaccines. In the present study, the aluminum contents of several vaccines (n = 19) routinely used in Turkey were, determined by electrothermal atomic absorption spectrophotometry. We found that aluminum levels in the vaccines ranged from 0.0 to 1438 mg/L.

Aluminum↗
PubMed1999

Chemical control of laryngeal vascular resistance in anesthetized dogs.

The branch of the cranial superior thyroid artery that supplies the larynx was perfused unilaterally at a constant flow rate in dogs anesthetized with pentobarbitone sodium (30 mg.kg-1, i.v.). Laryngeal vascular resistance (RLv) was calculated. Intraluminal laryngeal pressure (PL) was determined. Asphyxia caused a diminution in PL (-27.7 +/- 4.2%) (p < 0.01) and an initial decrease followed by an increase in RLv (-10.9 +/- 2.3% and +12.8 + 2.8%) (p < 0.001). Following vagotomy, asphyxia decreased PL (-17.1 +/- 4.2%) and increased RLv (+45.5 +/- 11.0%). Systemic hypoxia induced by breathing 8% O2-N2 increased RLv (+8.4 +/- 1.3%) (p < 0.001) and decreased PL (-24.9 +/- 3.7%) (p < 0.001). In chemodenervated dogs, the response of PL to hypoxia was abolished while that of RLv was similar to that in intact animals. Breathing of 7% CO2 in air caused an increase in RLv (+6.1 +/- 1.6%) (p < 0.001) and a decrease in PL (-20.9 +/- 3.2%) (p < 0.001). Following chemodenervation, hypercapnia still increased RLv (+11.3 +/- 3.2%) (p < 0.01) and diminished PL (-29.9 +/- 2.5%). Bilateral vagotomy reduced the response of PL to hypercapnia (-13.3 +/- 6.9%) (p < 0.05). Local intra-arterial injection of KCN produced an increase in RLv and PL (+7.0 +/- 1.2%, +9.0 +/- 1.0%). After peripheral chemodenervation KCN injection slightly increased PL (+2.0 +/- 0.9%). The response of RLv was almost abolished. In conclusion, laryngeal vasoconstriction in response to systemic hypoxia after chemodenervation is probably mediated by increased sympathetic discharge to the larynx due to hypoxia of the CNS. Laryngeal responses to hypercapnia may be due to the action of central chemoreceptors.

Animals↗
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

The aluminum content in some patch test allergens.

The Al content of 18 patch test allergens were measured by electrothermal atomic absorption spectrophotometry. It was found that these preparations contained Al in various amounts. We conclude that the presence of Al in patch test allergens may interfere with the diagnosis and evaluations of patients to whom the test is applied.

Allergens↗
PubMed1998

Urinary neopterin excretion and dihydropteridine reductase activity in rheumatoid arthritis.

Neopterin and biopterin are two products of the pteridine pathway. Even though their roles and interrelationships have not been exactly clarified, neopterin is known as a biomarker of cell-mediated immunity. In this case, the highly elevated neopterin levels are parallel to the slightly elevated biopterin levels. On the other hand, the reduced form of biopterin-tetrahydrobiopterin is an essential cofactor of aromatic monoxygenases that leads to synthesis of tyrosine, tryptophan and dopamine neurotransmitters and its concentration in body fluids and tissues is maintained by the enzyme dihydropteridine reductase (DHPR). Increased numbers of activated lymphocytes can be found in peripheral blood, in the synovial fluid and synovial membranes or patients with rheumatoid arthritis (RA). Since the present study was undertaken to evaluate the role of the pteridine pathway in RA, we measured urine neopterin levels and dried blood DHPR activities in 36 patients with RA and in 20 healthy volunteers, in parallel with other clinical parameters. We found that neopterin excretion was significantly increased in RA patients compared with controls. The means were 433 +/- 216, 153 +/- 43 and 111 +/- 34 mumol/mol creatinine for patients in active stage, in remission and controls, respectively. Our results suggest that urine neopterin levels were strongly dependent on the stage and activity of RA. Either as an effect of the disease itself or of drug administration, slightly reduced DHPR activities were detected (3.484 +/- 0.304 for control, 2.974 +/- 0.255 in active stage RA, and 3.048 +/- 0.302 red cytochrome C/min/5 mm disc in remission).

Adult↗
PubMed1998

Infantile muscle phosphorylase-b-kinase deficiency. A case report.

A Turkish girl is described who showed a severe floppy infant syndrome and respiratory failure at birth. She suffered upper respiratory tract infections and pneumonia. She was ventilated and had hypercapnoea secondary to bradypnoea. Biochemical analysis of skeletal muscle revealed a slightly increased glycogen content, and enzymatic analysis revealed a muscle phosphorylase-b-kinase deficiency. The infant succumbed after 140 days due to persistent apnoea and asystole. Isolated muscle phosphorylase-b-kinase deficiency should be considered as a possible diagnosis in floppy infants.

Brain Diseases, Metabolic↗
PubMed1998

The effect of central and peripheral administration of acetylcholine and epinephrine on respiration.

The experiments were conducted in dogs anesthetized with Na-pentobarbital i.v. tidal volume (VT) and respiratory frequency (f min-1) were recorded. The central effects of acetylcholine (Ach) and epinephrine on respiration were investigated after injections of these substances directly into the cerebrospinal fluid by atlanto-occipital punction. The peripheral effects of Ach and epinephrine on respiration were studied after i.v. injections. Both central and peripheral administration of epinephrine caused significant increase in f min-1 and VT. After vagotomy the effects of centrally and peripherally administered epinephrine on f min-1 were abolished. The effect of central injection of epinephrine on VT persisted after vagotomy. The increase in VT in response to peripheral epinephrine administration was abolished by vagotomy. Both central and peripheral injection of Ach increased f min-1. In VT an initial decrease was followed by an increase. The initial decrease in VT was abolished by atropine. After vagotomy the effects of central and peripheral administration of Ach on f min-1 were abolished. The effects of central injection of Ach on VT persisted after vagotomy. Vagotomy abolished the effects of peripheral administration of Ach on VT.

Acetylcholine↗
PubMed1997

Protective effect of magnesium supplementation on experimental 3-methyl cholanthrene-induced fibrosarcoma and changes in tissue magnesium distribution during carcinogenesis in rats.

In this study, we wanted to examine the effect of magnesium (Mg2+) supplementation on the experimental 3-methyl cholanthrene (3-MC)-induced fibrosarcoma and alterations in (Mg2+) distribution in several tissues of the rats, during carcinogenesis. It was determined that serum and tissue (Mg2+) levels of the rats in (Mg2+)-supplemented diet group were higher than those of the rats in the (Mg2+)-nonsupplemented and control groups. The mean time of fibrosarcoma development for (Mg2+)-supplemented group was longer than (Mg2+)-nonsupplemented group (p < 0.05). Symptoms of hypermagnesemia were not observed in any of the rats. These results suggests that dietary (Mg2+) supplementation may have a partial anti-carcinogenic effect on experimental 3-MC-induced fibrosarcoma by prolongation of the latent period of carcinogenesis.

Animals↗
PubMed1997

Colchicine derivatives inhibit neopterin production in human peripheral blood mononuclear cells (PBMC).

Colchicine is a microtubule disrupting agent, mostly used as treatment in various kinds of inflammatory diseases such as acute familial Mediterranean fever and Behcet's disease, as well as gout. In patients with familial Mediterranean fever treatment with colchicine induces a decline of urinary neopterin concentrations which indicates a decrease of cell-mediated immune activation. In this study, we investigated a potential effect of colchicine on the T cell/macrophage system in vitro. The human myelomonocytic cell line THP-1 and PBMC were treated with colchicine or the colchicine derivative, colcemide, in the presence or absence of 250 U/ml interferon-gamma (IFN-gamma) or 10 microg/ml lipopolysaccharide (LPS) for 48 h or 96 h. Colchicine and colcemide increased neopterin/protein production in unstimulated THP-1 cells, but no such effect was apparent in cells stimulated with IFN-gamma. By contrast, when PBMC were treated with colchicine or colcemide a significant reduction in neopterin formation was evident in cells without and with prestimulation by IFN-gamma or LPS. In parallel, reduced production of IFN-gamma was observed in PBMC. These data suggest that colchicine and colcemide are able to inhibit T cell activation within the cellular immune response.

Biopterins↗
PubMed1997

Central and peripheral effects of the non-neural substances on respiration before and after vagotomy.

The central effects of capsaicin, veratrine, histamine and bradykinin were studied by injecting them directly into the oerebrospinal fluid and their peripheral effects were examined by injecting into femoral vein. Our experiments were performed in Na-pentobarbital-anaesthetized dogs. Tidal volume (VT), respiratory frequency (f/min), systemic arterial pressure (BP) were recorded. A significant increase in f, and an initial apnea or hypoventilation followed by a significant increase in VT were observed with central and peripheral capsaicin. Vagotomy removed the peripheral VT response, but not the central one. While central capsaicin administration increased BP, peripheral administration decreased. After vagotomy, a significant increase was observed in BP for both administrations. Respiratory responses to central and peripheral administrations of veratrine were similar to those of capsaicin. Significant increases were observed in f and VT of the intact group in response to central and peripheral administration of histamine. Response to peripheral administration disappeared after vagotomy. While central and peripheral bradykinin increased VT significantly, there was no significant change in f. Vagotomy only removed the increase in VT in response to peripheral administration. In conclusion, respiratory responses to central administration of capsaicin and veratrine are due to direct effects of these substances on respiratory neurons. In peripheral administration, disappearance of the responses after vagotomy indicate that the responses are brought about by stimulation of the lung receptors.

Animals↗
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↗
PubMed1997

[Value of preoperative diagnosis in struma surgery].

To determine the usefulness of so-called routine diagnostic procedures prior to thyroid operations, in 2007 consecutive patients undergoing thyroid surgery from 1976 until 1991, the results of 1833 scintigraphy examinations, 1358 tracheal X-rays, 773 ultrasound examinations, 302 fine-needle aspiration biopsies (FNAB), and 73 frozen sections (FS) performed during operation were evaluated. Scintigraphy and ultrasound showed similar positive predictive values, ranging between 85% and 95%, in detecting thyroid nodules. The sensitivity of FNAB and FS were 44% and 83%, respectively. Mechanical alteration of the trachea was found to correlate to a high degree with severe postoperative respiratory disorders, requiring prolonged ventilation or tracheotomy either during primary surgery or as a secondary procedure.

Biopsy, Needle↗
PubMed1996

The effect of intraumbilical oxytocin on the third stage of labour.

The umbilical vein administration of oxytocin in saline was compared with umbilical vein saline alone and the traditional management of the third stage of labour. Seventy-two women were randomized to 3 groups. Group 1 received intraumbilical 20 IU of oxytocin diluted to 40 mL with saline. Group 2 received intraumbilical vein 40 mL of saline while subjects in group 3 were managed according to the standard protocol without any intraumbilical injection. No significant differences were found in terms of the length of the third stage, the blood loss in the third stage and postpartum haematocrit differences among the 3 groups. The administration of diluted oxytocin or saline do not seem to have any superiority to the traditional management of the third stage of labour.

Adult↗