Hakan Buyukhatipoglu

The Effects of Exogenous Melatonin on Peripheral Nerve Regeneration and Collagen Formation in Rats

BACKGROUND Peripheral nerve damage that requires surgical repair does not result in complete recovery because of collagen scar formation, ischemia, free oxygen radical damage, and other factors. To date, the best treatment method has not yet been determined. In this study, we designed an experimental peripheral nerve injury model, and researched the possible effects of melatonin hormone, based on evidence of its strong antioxidant and cell-protective effects via mimicking the effects of calcium channel blockers. MATERIALS AND METHODS We randomized 24 healthy female albino rats into three groups: the pinealectomy group, melatonin group, and control group. In the pinealectomy group, craniotomy, pinealectomy, sciatic nerve transection, and coaptation were performed, and 0.9% NaCl was injected intraperitoneally. In the melatonin group, craniotomy (without pinealectomy), sciatic nerve dissection, and coaptation were performed, and melatonin was injected intraperitoneally, instead of NaCl. In the control group, craniotomy (without pinealectomy), sciatic nerve dissection and coaptation, and intraperitoneal NaCl injection were performed. In each group, nerve recovery was evaluated histologically, functionally, and electrophysiologically. Functional and electrophysiologic evaluations were conducted before surgery and at 4 and 12 wk. RESULTS At 4 wk, no significant difference was observed between the groups. However, at 12 wk, significant electrophysiologic and functional improvement was observed only in the melatonin group. CONCLUSIONS Melatonin seems to have a beneficial effect on nerve recovery. However, this effect is not effective at physiologic doses. Future comparative studies with melatonin versus other nerve-regenerating agents are necessary to determine the clinical utility of melatonin hormone.

Effects of pulse methylprednisolone and oral methylprednisolone treatments on serum levels of oxidative stress markers in Graves' ophthalmopathy

Background  Recent evidence has shown that oxidative stress may play a role in the pathogenesis of autoimmune diseases, and this is an issue of considerable research interest in the field of infiltrative ophthalmopathy. Therefore, we evaluated both the relationship between Graves’ ophthalmopathy (GO) and serum levels of certain indicators of oxidative stress, and the effects of methylprednisolone treatment on serum malondialdehyde (MDA) and glutathione (GSH) levels in patients with euthyroid GO.

Oxidative Stress Increased in Healthcare Workers Working 24-Hour On-Call Shifts

Introduction:Long work hours, night shifts, stressful situations and insufficient social support increase levels of anxiety and depression and decrease motivation to perform among healthcare professionals. In this study, we evaluated oxidative stress levels in medical residents working 24-hour on-call shifts, and in nurses, relative to non-healthcare hospital staff in sedentary positions. We also measured serum prolidase activity, a measure of collagen turnover, as an objective proxy for level of physical activity. Methods:Fifty-five male and 15 female medical residents on 24-hour, in-house, on-call duty, and 45 nurses and 30 (15 male/15 female) non-healthcare staff working 8-hour shifts were recruited. All were healthy nonsmokers. Parameters of oxidative stress and serum prolidase activity were measured twice for each subject, upon arising at 8 am after an overnight fast; and then again near the end of the work shift, or after 16 hours of consecutive work (at 12 pm) for residents. Results:After hours of continuous work, serum total oxidative status and the oxidative stress index increased significantly, whereas total antioxidant status decreased (all P < 0.0001) in healthcare staff (nurses, male and female residents). All these variables remained virtually unchanged in non-healthcare staff. Similarly, serum prolidase activity increased in healthcare staff (P < 0.0001), but failed to increase statistically in non-healthcare staff. Conclusions:Healthcare workers suffer increased oxidative stress after prolonged work hours, especially while still on duty. Possible mechanisms for this include increased workload and, perhaps, psychological stress as well. However, long-term studies are needed to clarify the effects of sustained exposure to oxidative stress.

Serum prolidase activity in idiopathic and ischemic cardiomyopathy patients.

Idiopathic and ischemic dilated cardiomyopathies (DCM) are the most common types of DCM, and both exhibit the same histopathological feature of fibrosis. Prolidase is an enzyme that serves a rate‐limiting function in collagen turnover. Several studies have shown increased prolidase activity in fibrosis, though controversy persists. In this study, we measured prolidase enzyme activity in patients with idiopathic or ischemic DCM and in healthy controls, making this, to our knowledge, the first study to do so. What we found is that serumprolidase activity was significantly lower in both DCM groups relative to healthy volunteers and lower in ischemic DCM than idiopathic. These intriguing results could be attributed either to decreased collagen turnover in the heart tissues in which DCM develops, a result of diminished functional heart tissue, or to decreased physical activity levels among DCM patients stemming from their heart failure. Either way, further studies are needed to verify and clarify our results. J. Clin. Lab. Anal. 24:213–218, 2010.

Evaluation of Oxidative Stress Parameters and Urinary Deoxypyridinoline Levels in Geriatric Patients with Osteoporosis

[Purpose] To evaluate the oxidative stress parameters and urinary deoxypyridinoline levels in geriatric patients with osteoporosis. [Subjects and Methods] Eighty geriatric patients aged over 65 years were recruited. Patients were divided into two groups: Group 1 (n=40) consisted of patients with osteoporosis, and Group 2 (n=40) consisted of patients without osteoporosis. Bone mineral density measurements were performed for all patients using DEXA. Oxidative stress parameters were analyzed in blood samples, and deoxypyridinoline levels were analyzed in 24-hour urinary samples. [Results] Compared to Group 2, the total antioxidant status and oxidative stress index levels of Group 1 were not significantly different; however, total oxidant status and 24-hour urinary deoxypyridinoline levels were significantly higher. Pearson correlation coefficients indicated that OSI and urinary deoxypyridinoline levels were not correlated with any biochemical parameters. ROC-curve analysis revealed that urinary deoxypyridinoline levels over 30.80 mg/ml predicted osteoporosis with 67% sensitivity and 68% specificity (area under the curve = 0.734; %95 CI: 0.624–0.844). [Conclusion] Our results indicate that oxidative stress would play a role in the pathogenesis of osteoporosis, and that urinary deoxypyridinoline levels may be a useful screening test for osteoporosis.

Acute renal failure with the combined use of rosuvastatin and fenofibrate

Among the lipid-lowering drugs, the statins and fibrates are the most commonly used agents. Either class of drug is considered relatively safe. Though a variety of albeit uncommon adverse side effects have been observed with both classes, most of these therapeutic complications can be managed without discontinuation of the offending drug. Sometimes, especially in patients with extremely high cholesterol and/or triglyceride levels, a combination regimen is deemed necessary. However, the combined use of lipid-lowering drugs increases the incidence and severity of adverse events. In this article, we report an unusual case of acute renal failure (ARF) in a patient who had been prescribed both a statin (rosuvastatin) and a fibrate (fenofibrate).

Effect of combined angiotensin‐converting enzyme and aldosterone inhibition on plasma plasminogen activator inhibitor type 1 levels in chronic hypertensive patients

Aim:  A possible link between the renin–angiotensin–aldosterone system (RAAS) and fibrinolysis has recently been suggested. Systemic infusion of angiotensin II results in an increase in plasminogen activator inhibitor type 1 (PAI‐1) levels and angiotensin‐converting enzyme inhibitors (ACEI) have been shown to decrease PAI‐1 levels. Moreover, recent data indicated that plasma aldosterone levels were positively correlated with plasma PAI‐1 levels. This study was designed to compare the effects of an ACEI with an ACEI in combination with an aldosterone antagonist on PAI‐1 levels in chronic hypertensive patients.

Plasma Plasminogen Activator Inhibitor 1 (PAI-1) and p-Selectin Levels in Urgent Hypertension: Effect of Single Dose Captopril and Nifedipin on Fibrinolytic Activity

In this study, we primarily aimed to identify the acute effects of hypertension on fibrinolytic function in previously untreated urgent hypertensive patients and to evaluate the influence of two commonly used, short-acting, anti-hypertensive agents, captopril and nifedipine, in these patients. Patient groups were selected homogeneously, i.e., only previously untreated patients amidst an urgent hypertensive episode and having no co-morbid disease were included–and randomly assigned to receive either captopril or nifedipine for immediate management. These two treatment groups were matched for age, gender, and mean arterial blood pressure. Study results demonstrated that lowering blood pressure with either agent improved fibrinolytic function; however, in those patients given captopril, this beneficial effect was more prominent, providing evidence supporting the preferential use of short-acting, angiotensin-converting enzyme (ACE) inhibitors in this setting.

Impaired Fibrinolytic and Blunted Nitric Oxide Response to Phlebotomy in Cigarette Smoking Healthy Blood Donors

This study was designed to investigate the effects of smoking on endothelial function in 88 healthy blood donors: 48 smokers and 40 non-smokers. Two markers of endothelial dysfunction, plasminogen activator inhibitor-1 (PAI-1) and nitric oxide (NO) levels, were measured at baseline and after phlebotomy. It has been proposed that phlebotomy acutely activates the renin–angiotensin–aldosterone system, thereby activating endothelial activity and increasing PAI-1 and NO expression. At baseline there were no significant differences between smokers and non-smokers in terms of PAI-1 expression and NO levels. After phlebotomy, both PAI-1 and NO levels were significantly increased in both groups. The increase in PAI-1 was more pronounced in smokers and the increase in NO was more pronounced in non-smokers. These findings suggest that smoking causes endothelial dysfunction, even in healthy smokers, which may remain silent until a clinically evident disorder develops.

Crohnic kidney disease: Recurrent acute kidney failure in a patient with Crohn's disease

Context: Short bowel syndrome is a rare and devastating complication in chronic inflammatory bowel disease following functional or anatomic loss of extensive segments of the intestine. Case Report: A 60-year-old male patient with Crohns disease had undergone multiple resections of the intestine and developed short bowel syndrome. Despite up to 4-5 liters of orally fluid, sufficient calcium and magnesium intake, he suffered from recurrent acute kidney injury due to profound volume depletion and those electrolyte deficiencies. Administration of intravenous fluid and electrolyte repleacement treatment at regular intervals prevented further kidney injuries. Conclusion: We present a case of recurrent acute kidney failure in a patient with Crohns disease, and aimed to remark importance of receiving sufficient parenteral fluid and electrolyte support in those with short bowel syndrome.