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Biomedical subjects

M Tuncer

Publications and source records attributed to M Tuncer.

At least 73 records · Page 4Linked to original sources
PubMed1999

ATP-MgCl2 utilization for spinal cord protection during experimental thoracic aortic occlusion.

BACKGROUND: In this experimental study we investigate the effect of intravenous ATP-MgCl**2 administration for prevention of spinal cord injury occurring due to ischemia induced by aortic cross clamping. METHODS: Ten rabbits were studied. The abdominal aorta is ligated below the left renal artery. Five rabbits served as a control group and received no medication during 30 minutes of ischemic period. The other 5 rabbits received during 30 minutes of aortic occlusion ATP-MgCl2 solution (100 micromol/ml for each). Distal and proximal aortic pressures are measured during the procedure and incisions are closed. Rabbits are observed for 24 hours for their neurological status and scored accordingly. Specimens from the spinal cord are taken for electron microscopic investigations. RESULTS: All of the control group rabbits were paraplegic. One of the ATP-MgCl2 group rabbits was paraparesic and the others were normal Distal aortic pressure was 9+/-3 mmHg for the control group and was 17+/-4 mmHg for the ATP-MgCl2 group (p<0.05). Electron microscopic studies showed the preserved ultrastructure for ATP-MgCl2 group. CONCLUSIONS: ATP-MgCl2 administration during spinal cord ischemia reduces spinal cord injury. This may be an alternative modality for the protection of the spinal cord during aortic surgery.

Adenosine Triphosphate↗
PubMed1999

Response to triple treatment with omeprazole, amoxicillin, and clarithromycin for Helicobacter pylori infections in continuous ambulatory peritoneal dialysis patients.

In this study, the response to triple treatment with omeprazole, amoxicillin, and clarithromycin was investigated in continuous ambulatory peritoneal dialysis (CAPD) patients with Helicobacter pylori (Hp) infections. The study enrolled 20 CAPD patients (11 male, 9 female) who had dyspeptic complaints. The mean age of the patients was 46 (range: 21-65). The study also enrolled, as a control group, 124 patients (66 male, 58 female) who had no systemic disease, but who had upper gastrointestinal endoscopy for dyspeptic complaints. The mean age of the patients in the control group was 47 years (range: 20-74 years). Upper gastrointestinal endoscopy, rapid urease test (CLO test), and direct histologic examination were carried out to detect Hp infection. Hp infection was detected in 10 cases (50%) in the CAPD group and in 53 cases (43%) in the control group. In both groups, patients with Hp infection received the triple treatment of omeprazole 20 mg twice daily for 30 days, amoxicillin 500 mg thrice daily for 15 days, and clarithromycin 500 mg thrice daily for 15 days. To assess response to treatment, upper gastrointestinal endoscopy, CLO test, and direct histologic examination were repeated 3 months after initiation of the treatment. Hp was eradicated in all of the 11 CAPD patients (100%), and in 42 of the control patients (92%). Our results suggest that the triple treatment with omeprazole, amoxicillin, and clarithromycin for Hp infection is as effective in CAPD patients as in the normal population.

Adult↗
PubMed1998

Congenital erythropoietic porphyria successfully treated by allogeneic bone marrow transplantation.

The long-term biochemical and clinical effectiveness of allogenic bone marrow transplantation (BMT) was shown in a severely affected, transfusion-dependent 18-month-old female with congenital erythropoietic porphyria (CEP), an autosomal recessive inborn error of heme biosynthesis resulting from mutations in the uroporphyrinogen III synthase (URO-synthase) gene. Three years post-BMT, the recipient had normal hemoglobin, markedly reduced urinary porphyrin excretion, and no cutaneous lesions with unlimited exposure to sunlight. The patient was homoallelic for a novel URO-synthase missense mutation, G188R, that expressed less than 5% of mean normal activity in Escherichia coli, consistent with her transfusion dependency. Because the clinical severity of CEP is highly variable, ranging from nonimmune hydrops fetalis to milder, later onset forms with only cutaneous lesions, the importance of genotyping newly diagnosed infants to select severely affected patients for BMT is emphasized. In addition, the long-term effectiveness of BMT in this patient provides the rationale for future hematopoietic stem cell gene therapy in severely affected patients with CEP.

Bone Marrow Transplantation↗
PubMed1998

Vasodilatation induced by nicotine in the isolated perfused rat kidney.

1. In isolated perfused rat kidney, under a constant flow of 8-10 ml/min, mean basal perfusion pressure was found to be 82.57 +/- 8.96 mm Hg (n = 70). 2. After a bolus injection of 10 micrograms/0.1 ml phenylephrine (PE) which causes maximum vasopressor response, a 93.27 +/- 0.56 mm Hg increase in basal perfusion pressure was recorded (n = 70). In control experiments, a submaximum dose of PE (3 x 10(-6) M) caused a 68.37 +/- 0.47 mm Hg (n = 5) increase in perfusion pressure. 3. Nicotine, at a dose of 100 micrograms/0.1 ml, decreased the perfusion pressure raised by submaximum dose of PE. This nicotine-induced dilatation was 24.97 +/- 3.27% of maximum PE constriction (n = 5). 4. Nicotine-induced dilatation was not affected by atropine, guanethidine, hexamethonium, tetrodotoxin, capsaicin, indomethacin, quinacrine, NG-nitro-L-arginine, methylene blue, glibenclamide, tetraethylammonium, 4-aminopyridine and ouabain (n = 5).

Animals↗
PubMed1998

Attenuation of ischemia--reperfusion injury by enalapril maleat.

1. The aim of this study was to investigate the effects of enalapril maleate on ischemia-reperfusion injury of the myocardium, after cardioplegic arrest in isolated guinea pig hearts, in a modified Langendorff model. 2. Animals were subjected to 90 min of normothermic global ischemia, followed by 30 min of reperfusion. Cardioplegic arrest was achieved by administering St. Thomas Hospital cardioplegic solution (STHCS). 3. The hearts were randomly allocated into four groups (n=8 in each group). The first group was utilized as control. In the second group, oral pretreatment was made (0.2 mg/kg enalapril maleat was given twice a day for 10 days). In the third group, enalapril maleat (1 micromol/l) was added to STHCS. In the fourth group, hearts were arrested with enalapril maleat-enriched STHCS, and enalapril maleat-enriched (1 micromol/l) Krebs-Henseleit solution was applied during the reperfusion period. 4. Although the study groups showed better recovery of contractility than did the control group, in the last group, the hearts had the best recovery of left ventricular systolic function, where dp/dt maximum was 89.7+/-6.9% of the preischemic values. Group 1, group 2 and group 3 achieved 44.2+/-4.5%, 79.4+/-5.8% and 68.1+/-6.7% of their preischemic dp/dt values. A similar observation was found for left ventricular developed pressure (LVDP); LVDP values were 52.4+/-2.1% (in group 1), 79.6+/-2.8% (in group 2), 72.8+/-4.6% (in group 3) and 86.7+/-5.8% (in group 4) of control after reperfusion. Creatine kinase leakage was significantly lower and postischemic coronary flows were significantly higher in group 4. 5. We concluded that usage of enalapril maleat in the reperfusion period was more effective for improving myocardial recovery after cardioplegic arrest. The additional protective effects of enalapril maleat not only were by angiotensin-converting-enzyme-inhibition-dependent coronary vasodilation and thiol-dependent limitation of oxidative injury, but could also be related to an oxygen-free-radical-scavenging effect.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

The possible role of endothelin(s) in cyclosporine A preparations--induced contraction of guinea pig isolated gallbladder strips.

1. In guinea-pig isolated gallbladder strips, both cyclosporine A (CyA) preparations and their vehicles (10(-7) M-4 x 10(-5) M) caused stable, long-lasting and concentration-dependent contractions. 2. Some gallbladder strips showed spontaneous rhythmic activity. CyA and its vehicles increased this rhythmic activity. Furthermore, they elicited rhythmic activity in the strips that did not show any spontaneous rhythmic activity. 3. Bosentan (10(-5) M) and verapamil (10(-5) M) partly but significantly inhibited the contractions due to CyA preparations and their vehicles except the effect of verapamil on Labrafil-induced contraction. 4. Neither parenteral and oral solutions of CyA nor their vehicles caused any contractile response on the sphincter of Oddi preparations.

Animals↗
PubMed1998

Beneficial effect of captopril against ischaemia-reperfusion injury in isolated guinea pig hearts.

The study was designed to clarify whether captopril, an angiotensin-coverting enzyme inhibitor, will reduce the injury of global ischaemia and reperfusion after cardioplegic arrest in isolated guinea pig hearts, in a modified Langendorff model. The hearts were randomly allocated into four groups (n = 10 in each) and subjected to 90 min of normothermic global ischemia, followed by 30 min of reperfusion; in all groups, cardioplegic arrest was achieved by administering St. Thomas's Hospital cardioplegic solution (STHCS). The first group was utilized as the control group. In the second group, captopril (200 mumol/L) was added to STHCS. In the third group, oral pretreatment was carried out (0.3 mg/kg captopril was given twice a day for 10 days). In the fourth group, oral pretreatment was achieved and captopril-enriched solution was applied in the first 5 min of reperfusion. Although the study groups showed better recovery of contractility than the control group, in the fourth group the hearts had the best left ventricular contractile function, where contractile force (g contractility/g heart weight) was 55.4% +/- 3.8% of the preischameic values. Groups I, II, and III achieved 31.0% +/- 3.2%, 41.6% +/- 3.8%, and 48.3% +/- 3.9% of their preischaemic contractile force values. Creatine kinase leakage was significantly lower and postischaemic coronary flows, too, were significantly higher in the fourth group. Coronary flow after reperfusion increased from 48.5 +/- 6.7 to 65.2 +/- 7.1 ml/min g heart in group 4 (p < 0.05). Myocardial lipid peroxides and glutathione contents showed that there was a correlation between the depletion of myocardial glutathione content and increased lipid peroxidation. These preliminary results showed that: the addition of captopril to reperfusion solution and oral preconditioning improved post-ischameic myocardial function and decreased myocardial injury.

Administration, Oral↗
PubMed1998

Allogeneic bone marrow transplantation in Fanconi anemia from Turkey: a report of four cases.

Bone marrow transplantation (BMT) is currently the treatment of choice for patients with Fanconi anemia (FA) if a suitable donor is available. Four children with FA underwent allogeneic BMT from HLA-identical siblings during the period from 1995 to 1996. Pretransplant conditioning was Cyclophosphamide (Cy) (20 mg/kg) + Thoracoabdominal irradiation (TAI) (500 cGy) +/- Antithymocyte globulin (ATG) (2 mg/kg/day x 3). Cyclosporin A (CsA) was used as GvHD prophylaxis. The time of neutrophil (ANC>500) and platelet (>50,000) recovery were at 11-14 and 17-25 days, respectively. One patient with a pretransplant history of multiple transfusions experienced graft rejection and died at day +29 with infection and bleeding. Although three patients sustained engraftment one developed donor originated acute lymphoblastic leukemia (ALL) 18 months after BMT and died with CNS hemorrhage and infection at +25 months following 7 months of chemotherapy. None of the patients developed grade 3-4 acute GvHD. Cytotoxicity included grade II mucositis in all and severe gastroenteritis in one patient. During a follow-up period of 10 months and 2 years, two patients are well with normal blood count, recovering immune function and have a Karnofsky score of 90%.

Adolescent↗
PubMed1997

Protective effect of antioxidant vitamins on red blood cell lipoperoxidation induced by SO2 inhalation.

The aim of this research was to determine whether administration of antioxidant vitamins can reduce oxidant damage in erythrocytes induced by sulfur dioxide (SO2) inhalation. Meth- and sulfhemoglobin ratios, malonyldialdehyde (MDA) levels, osmotic fragility ratios and hematological parameters of a total of 28 rats were compared. SO2 was given at 10 ppm, 1 hour daily, for 45 days in a specially designed chamber. DL-alpha-Tocopherol acetate (40 mg/kg) and Na-ascorbate (200 mg/kg) treatments, initiated 3 days before SO2 exposures, were applied intraperitoneally 3 times a week for 45 days. Meth- and sulfhemoglobin ratios, MDA levels and osmotic fragility ratios were significantly higher in the SO2-treated group (p < 0.05). Significant decreases in MDA levels and osmotic fragility ratios were observed in the antioxidant-treated group (p < 0.05). SO2 inhalation resulted in higher MDA levels and osmotic fragility ratios, which can be reduced by vitamin E + C combination.

Air Pollutants↗
PubMed1997

Clinical effects of diflunisal and paracetamol in impacted mandibular third molar surgery.

A double-blind, randomized, cross-over study to compare diflunisal and paracetamol for postoperative pain, swelling and trismus relief following impacted mandibular third molar surgery was designed. 25 patients received one of the drugs at one visit and the alternative at the other visit. First doses were given two hours preoperatively and continued twice daily for five days. The study was carried out to determine the effect of preoperatively used diflunisal on postoperative pain after surgical removal of the third molars as compared to paracetamol used in a similar manner. The degree of impaction, pain, swelling and mouth opening were assessed by standardized methods and possible adverse effects were also recorded separately. Statistical analysis was carried out by "Student's t test". (p < 0.01 statistically significant).

Acetaminophen↗
PubMed1996

Hypertension increases the contractions to sumatriptan in the human internal mammary artery.

BACKGROUND: The internal mammary artery is the graft of choice for myocardial revascularization. The tendency to spasm increases toward the distal end of the internal mammary artery, which is the portion generally used for anastomosis. The distal internal mammary artery is more pharmacologically responsive to 5-hydroxytryptamine and several other vasoconstrictor agents than its midsection. METHODS: We examined the effects of 5-hydroxytryptamine and a 5-hydroxytryptamine1-like receptor agonist sumatriptan on internal mammary artery segments (length, 3-4 mm) obtained from patients undergoing coronary artery bypass grafting. To unmask a 5-hydroxytryptamine1-like receptor-mediated contractile response, threshold concentrations of potassium chloride were used. RESULTS: 5-Hydroxytryptamine induced concentration-dependent contractions in all, quiescent and potassium chloride precontracted, preparations. Sumatriptan induced marked contraction in some of the quiescent internal mammary artery rings, whereas it elicited marked and concentration-dependent contractions in all of the preparations given a moderate tone by a threshold concentration of potassium chloride. The sensitivity to sumatriptan was higher in potassium chloride-precontracted distal arteries than it was for the quiescent distal segments. Additionally, the sensitivity to and the efficacy of sumatriptan were much more markedly potentiated by precontraction in the preparations taken from hypertensive patients. CONCLUSIONS: The more marked potentiation of the responses in arteries from hypertensive patients may be one of the factors influencing the patency rates.

Aged↗
PubMed1996

Effects of Androctonus crassicauda scorpion venom on endothelium-dependent and -independent vascular responses of rabbit aorta.

The effects of Androctonus crassicauda scorpion venom on acetycholine (ACh)-induced relaxations and contractions of rabbit thoracic aorta were studied. Endothelium-dependent relaxations induced by ACh in phenylephrine-precontracted arteries were enhanced by the scorpion venom. ACh-induced contractions in endothelium-intact open aortic rings were less than those obtained in denuded preparations (n = 6, P < 0.05, ANOVA). Venom (5, 10 and 30 micrograms/ml) potentiated ACh-induced contractions in intact and denuded segments. In the denuded segments, this potentiation was inhibited by indomethacin (10 microM). Thromboxane synthase inhibitor, BW 149H (100 microM) and thromboxane A2 (TXA2) receptor antagonist, R 68070 (10 microM) partly inhibited venom-induced potentiation. NG-nitro-L-arginine (100 microM) increased venom-potentiated ACh responses in intact arterial segments. Venom increased the basal tone by 25-35% at 30 micrograms/ml. These results suggest that A. crassicauda venom may release a relaxing factor from endothelium and contracting factor from the smooth muscle of rabbit isolated thoracic aorta. The contracting factor may be a cyclooxygenase-like product, most likely TXA2. The increase in basal tone by 30 micrograms/ml venom was inhibited by phentolamine (10 microM) and guanethidine (10 microM), indicating a venom-induced release of a neurotransmitter from adrenergic nerve endings.

Acetylcholine↗