Browsing by Author "Sayin, Refah"

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Atypical Virchow-Robin Spaces: Report of Seven Cases
(Ortadogu Ad Pres & Publ Co, 2010) Avcu, Serhat; Sayin, Refah; Unal, Ozkan; Cogen, Etem Emre; Tombul, Temel
The term "Virchow-Robin spaces" (VRS) refers to the extension of the subarachnoid space accompanying a vessel penetrating the cerebral cortex. In case of widening, they can be seen on magnetic resonance imaging as round, oval, or curvilinear well-defined cystic lesions with smooth margins, isointense to cerebrospinal fluid. Although dilated VRS are normal findings that may be seen at all ages, big and atypical forms are rare. Although they have associated mass effect, they should not be mistaken for neoplasm or other disease. We report seven patients whose ages were between 7 and 66 (mean: 35.8) years showing unilateral or bilateral cerebral intraparenchymal extensive cystic dilations corresponding to atypical VRS (two with Type-I and five with Type-II VRS), with clinical and radiological findings.
Autonomic Symptoms in Migraineurs: Are They of Clinical Importance
(Galenos Yayincilik, 2011) Milanlioglu, Aysel; Tombul, Temel; Sayin, Refah; Odabas, Omer Faruk; Sahin, Musa
Aim: The aim of this study was to evaluate the presence of autonomic symptoms in migraine patients with and without aura and to investigate whether there is an association between expression of autonomic symptoms and disease duration, headache side, attack duration and frequency. Methods: The study sample comprised 82 subjects in headachefree phase including 20 migraine with aura patients and 62 - without aura; 61 were females (74.39%) and 21 were males (25.61%). The mean headache frequency was 2.63 +/- 1.29 per month and the mean duration of headache occurrence was 10.04 +/- 7.26 years from the first episode. The subjects were asked whether or not they had autonomic symptoms like diaphoresis, diarrhea, eyelid oedema, pallor, flushing, syncope or syncope-like episode, constipation, palpitation, diuresis, blurred vision, sensation of chills and coldness during each migraine headache. Results: Of all 82 migraine patients, 50 (60.98%) experienced at least one of the autonomic symptoms during the attack periods. The most common symptom was flushing (39.2%). Among the autonomic symptoms, syncope or syncope-like episode was significantly more in patients without aura compared to those with aura (p< 0.05). In this study, patients who experienced autonomic symptoms during their headache attack had statistically significantly higher attack frequency (p= 0.019). Conclusion: This result indicate that migraine patients with autonomic nervous system involvement have more frequent headaches, therefore these patients should be particularly and cautiously investigated.
Bilateral Brachial Plexus Palsy and Right Horner Syndrome Due To Congenital Cervicothoracal Syringomyelia
(Elsevier Science Bv, 2010) Cagan, Eren; Sayin, Refah; Dogan, Murat; Peker, Erdal; Cagan, Havva Hasret; Caksen, Hueseyin
Syringomyelia (SM) is a disorder in which a cyst forms within the spinal cord. This cyst, called a syrinx, expands and elongates over time, destroying the center of the cord. Horner syndrome is an infrequent illness caused by a lesion of the cervical sympathetic nerve fiber. Its clinical features are facial anhidrosis, ptosis, miosis, and hypochromia iridis of the affected side. A full-term male newborn infant was admitted with weakness in bilateral upper extremities and narrowing of the palpebral fissure on the right side. Ophthalmologic examination revealed a smaller right pupil. Muscle power in bilateral upper limbs was 1/5. Chest X-ray and cranial magnetic resonance imaging were normal. Magnetic resonance imaging of the cervicothoracic spine showed SM at C4-T2 level. Electromyographic examination revealed bilateral brachial plexus palsy. The diagnosis was of brachial plexus palsy and congenital Homer syndrome due to congenital cervicothoracic SM. According to our best knowledge, this association has not been reported in the literature. (C) 2009 Elsevier B.V. All rights reserved.
Cerebral Venous Sinus Thrombosis Presentation in Emergency Department in Van, Turkey
(Pakistan Medical Assoc, 2014) Karadas, Sevdegul; Milanlioglu, Aysel; Gonullu, Hayriye; Sayin, Refah; Aydin, Mehmet Nuri
Objective: To exmaine the distribution of age, gender, time between onset and presentation, clinical findings, predisposing factors, platelet distribution width, mean platelet volume values and neuroimaging findings, together with the treatment regime and the outcome for patients of cerebral venous sinus thrombosis. Methods: The retrospective, descriptive cross-sectional study was conducted at Yuzuncu Yil University, Medical Faculty Hospital in Van, Turkey, comprising 51 cases diagnosed with cerebral venous sinus thrombosis between January 2008 and September 2011. The diagnosis was based on the results of clinical evaluation, cranial magnetic resonance imaging and venography. SPSS 16 was used for statistical analysis. Results: Overall, 43 (84.3%) of the cases were female, and 8(15.7%) were male. The average age was 32 +/- 11.13 years. The most frequent symptom was headache in 41 (80.4%) cases. The postpartum period was one of the most observed predisposing factors in 17 (33.3%) patients. The magnetic resonance imaging was normal in 35 (68.6%) cases, but in all of the cases, magnetic resonance venography was abnormal. Topographically, the most frequent involvement was transverse sinus in 40 (78.4%) cases. Besides, 50 (98%) patients were discharged following full recovery or mild sequela and only 1 (2%) case had severe sequela. Conclusion: Patients presenting with headache should be examined carefully in the emergency department. Early diagnosis and treatment with clinical and neuroimaging techniques for such patients is recommended.
Chronic Paroxysmal Hemicrania Responsive To Lamotrigine
(Professional Medical Publications, 2011) Milanlioglu, Aysel; Tombul, Temel; Sayin, Refah
This report details a 45-year-old woman who has been suffering right-sided temporal and orbital headache attacks during last five years. The pain is characteristically associated with ipsilateral lacrimation, ptosis and rhinorrhoea. The frequency and duration of pain increased dramatically within last two years. Detailed neurological, physical and clinical examinations as well as routine blood tests revealed no abnormality. Magnetic resonance imaging of brain was normal. The patient was clinically diagnosed as chronic paroxysmal hemicrania and initially treated with indomethacin. Due to appearance of epigastric pains indomethacin treatment was replaced with lamotrigine which successfully resolved the symptoms.
Clinical and Perinatal Outcomes in Eclamptic Women With Posterior Reversible Encephalopathy Syndrome
(Springer Heidelberg, 2015) Kurdoglu, Zehra; Cetin, Orkun; Sayin, Refah; Dirik, Deniz; Kurdoglu, Mertihan; Kolusari, Ali; Sahin, H. Guler
Purpose To compare the clinical and perinatal outcomes in eclamptic women with and without posterior reversible encephalopathy syndrome (PRES). Methods This single-center, retrospective, cohort study was conducted between 2008 and 2013. The clinical and perinatal outcomes of eclamptic patients were obtained from hospital records. Magnetic resonance imaging was used for the diagnosis of PRES. Eighty-one eclamptic women were divided into two groups: 45 and 36 patients were included in the PRES and non-PRES groups, respectively. Results In the PRES group, headache and visual impairment together (60.0 %) were the most common presenting symptoms. In the non-PRES group, only headache was the most common (50 %) presenting symptom. Occipital and parietal lobes were the most frequently affected areas in the PRES group. Women in the PRES group had a higher body mass index value (p = 0.005), longer hospitalization time (p = 0.001), and higher level of proteinuria (p = 0.012) than those in the non-PRES group. Women in the non-PRES group had higher Apgar scores (p = 0.002) than those in the PRES group. Conclusions This study indicates that PRES manifests predominantly with headache and visual impairment together. Adverse neonatal outcomes are also common in these patients.
Clinical Features and Prognosis With Guillain-Barre Syndrome
(Wolters Kluwer Medknow Publications, 2011) Akbayram, Sinan; Dogan, Murat; Akgun, Cihangir; Peker, Erdal; Sayin, Refah; Aktar, Fesih; Caksen, Huseyin
Background: Guillain-Barre syndrome (GBS) is an acute inflammatory polyneuropathy commonly characterized by rapidly progressive, symmetric weakness and areflexia. Materials and Methods: We retrospectively assessed the clinical manifestations, results of electrodiagnostic tests, functional status and prognosis of 36 children diagnosed with GBS. Results: Based on clinical and electrophysiological findings, the patients were classified as having acute inflammatory demyelinating polyradiculoneuropathy (AIDP) (n = 25), acute motor axonal neuropathy (AMAN) (n = 10) and acute motor-sensory axonal neuropathy (AMSAN) (n = 1). Twenty (55.5%) patients were males and 16 (44.5%) patients were females. The mean age of the 36 patients was 68.1 +/- 45.01 months (range, 6-180 months). Five (13.8%) patients were younger than 2 years. The most common initial symptoms were limb weakness, which was documented in 34 (94.4%) patients. In our study, 18 patients (51.4%) showed albuminocytological dissociation (raised protein concentration without pleocytosis) on cerebrospinal fluid (CSF) examination. Three patients (8.3%) required mechanical ventilation therapy during hospitalization. Unfortunately, three (8.3%) patients died; one patient had AIDP and two patients had axonal involvement (one case was AMAN and another case was AMSAN). When we compared the cases of residual sequel/dead and cases of complete recovery for neural involvement type including AIDP, AMAN and AMSAN, we did not find a statistically significant difference between the groups (P > 0.05). Conclusion: Our findings showed that cases of GBS was not uncommon in children younger than 2 years of age, and CSF protein level might be found high in the first week of the disease in about one half of the patients, with a higher rate of morbidity and mortality in patients with axonal involvement than in those with AIDP.
Clinical Overlap of Multiple Sclerosis and Autoimmune Hepatitis: Three Cases
(Coll Physicians & Surgeons Pakistan, 2016) Sayin, Refah; Gokgul, Alper; Ebinc, Senar; Dulger, Ahmet Cumhur; Tombul, Temel
Multiple sclerosis (MS) is an autoimmune, inflammatory disease characterized by demyelination and axonal degeneration in the central nervous system. MS is the second major cause of disability following trauma, and is mostly seen between the ages of 20 - 40 years and in women. Autoimmune hepatitis (AH) is a chronic disease characterized by hypergammaglobulinemia, high levels of transaminases, presence of antibodies, and histologically by the necroinflammatory process with interface hepatitis. In AH, the etiological agent of the disease and the cause of liver injury remain unknown. MS may be associated with AH, autoimmune thyroiditis, and type 1 diabetes mellitus (DM). In literature, 8 cases with overlap of MS and AH have been reported. In this report, we present 3 cases which were detected with overlap of MS and AH, and are very rare condition in literature.
Coexistence of the Poems Syndrome With Hepatitis B: a Rare Case Report
(Springer Wien, 2016) Celik, Yilmaz; Aslan, Mehmet; Sayin, Refah; Cifci, Adem; Canbaz, Esra Turan; Kucukoglu, Mehmet Emin; Dulger, Ahmet Cumhur
POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) is a rare multisystemic disease of unknown pathogenesis. Proinflammatory and proangiogenic cytokines play important roles in its pathogenesis. POEMS syndrome is a rare cause of ascites. Until now, the coexistence of POEMS syndrome and hepatitis B has not been reported. In this case report, we present a 48-year-old male patient who presented with malaise, fatigue, diarrhea, and abdominal swelling. Organomegaly, endocrinopathy, ascites, skin changes, and polyneuropathy were identified, and we arrived at a diagnosis of POEMS syndrome. The patient was administered methylprednisolone 64 mg/day, lamivudine 100 mg/day, calcium 1.5 g/day, and calcitriol 0.5 A mu g/day. The patient's clinical manifestations had moderately resolved at the follow-up visits. At the end of 6 months of follow-up, his ascites was minimally reduced, and his neurologic manifestations had not lessened. The present case shows that accurate diagnosis is required for the management of patients with coexisting POEMS syndrome and hepatitis B.
Electrophysciological Analysis of Entrapment Neuropathies Developed in Acute and Subacute Period in Paretic and Non-Paretic Extremities in Patients With Stroke
(Pakistan Medical Assoc, 2012) Odabas, Faruk Omer; Sayin, Refah; Milanlioglu, Aysel; Tombul, Temel; Cogen, Etem Emre; Yildirim, Gokhan
Objective: To investigate entrapment neuropathies in stroke patients in a hospital in Turkey with Medical Research Council (MRC) score <= 2/5 and in those with MRC score >= 3/5. Methods: The study comprising 40 patients from January 2008 to June 2009 in the Stroke Unit of the Department of Neurology, Yuzuncu Yil University in Van, Turkey, entailed electrophysiological analysis of median, ulnar, radial nerves, peroneal, tibial and sural nerves in paretic and nonparetic upper and lower extremities. National Institute of Health Stroke scale was used for the evaluation of neurological deficient, while nerve conduction studies were performed for the diagnosis of entrapment neuropathies (EN). The patients were divided into two groups based on their initial Medical Research Council (MRC) score: < 2/5 and > 3/5. Both groups had 20 patients each. The readings were compared in the control phase 45 to 50 days after the stroke. Paired samples test and t-test using SPSS version 15 were used for statistical analysis. Results: Carpal tunnel syndrome (CTS) at wrist was found in 7 (35%) patients, cubital tunnel syndrome at elbow in 3 (15%) patients, and evident reduction in motor action potential values of peroneal, median and ulnar nerve in 10 (50%) patients in the control studies for conduction on our patients with Medical Research Council (MRC) score of <= 2/5, unlike the initial findings, in the paretic side. Among the patients, in the other group, 2 (10%) developed bilateral Camel tunnel syndrome, and it was also detected in the healthy upper extremities in 2 (10%) more patients. In the control studies for conduction in patients with Medical Research Council score of >= 3/5, Camel tunnel syndrome was detected in the healthy side in 4 (20%) patients and in the affected side in 3 (15%) patients. Conclusion: In patients with severe paresis, if the affected extremity is not functional, symptoms of entrapment neuropathy are easy to occur.
Evaluation of Several Classification Methods in Carpal Tunnel Syndrome
(Pakistan Medical Assoc, 2017) Sayin, Refah; Keskin, Siddik; Hamamci, Mehmet
Objective: To investigate the performance and effectiveness of 4 classification methods including support vector machine, naive Bayes, classification tree, and artificial neural network in the detection of carpal tunnel syndrome. Methods: This retrospective study was conducted at Yuzuncu Yil University, Van, Turkey, and comprised record of patients suspected of having carpal tunnel syndrome between January and December 2013. The evaluations included age, gender, and 6 electromyography variables, including right/left median nerve sensory velocity, right/left fourth finger peak latency difference, and right/left median nerve motor distal latency. We investigated the performance of classification methods such as support vector machine, naive Bayes, classification tree and artificial neural network in the patients using data obtained from electromyography scan. A total of 6 criteria were used for the assessment of performance, including: true positive rate, false positive rate, true negative rate, false negative rate, accuracy, and preciseness. Results: Of the 109 patients, 88(80.7%) were women and 21(19.3%) men. Besides, 67(61.5%) participants had carpal tunnel syndrome and 42(38.5%) did not have it. On classification tree, only 2 variables, i.e. left fourth finger peak latency difference and right/left median nerve sensory velocity, were found to be statistically significant (p<0.001). Naive Bayes had the highest detection score (91.04%), followed by support vector machine (89.55%). Conclusion: Naive Bayes yielded better performance than all the other methods in the diagnosis of carpal tunnel syndrome, followed by support vector machine.
Guillain-Barre Syndrome Following Spinal Anaesthesia
(Coll Physicians & Surgeons Pakistan, 2013) Sayin, Refah; Kati, Ismail; Isik, Yasemin; Gunes, Mustafa
Guillain-Barre Syndrome (GBS) is the most common disease resulting in acute diffuse flaccid paralysis. It is an autoimmune disease that can occur at any age. The clinical course is characterized by weakness in the arms and legs, areflexia and the progression of muscle weakness from the lower limbs to the upper limbs. The most common causes of GBS include infections, vaccinations, surgery and some medicines. We present the case of a 48 years old male patient, who developed GBS after undergoing surgery for renal calculus, under spinal anaesthesia. In this case report, we presented a rather rare case of GBS occurring following spinal anaesthesia.
Hot Water Epilepsy in a Pregnant Woman: a Case Report
(Hindawi Ltd, 2010) Milanlioglu, Aysel; Tombul, Temel; Sayin, Refah
Hot water epilepsy is a unique form of reflex epilepsy precipitated by the stimulus of bathing with hot water poured over the head. It is mostly seen in infants and children, with a predominance in males. Unlikely, we present a 32-year-old pregnancy woman with the incipient of reflex seizures triggered by pouring hot water over the head while having a bath during the gestation period and treated successfully with carbamazepine 400mg/day therapy. Hot water epilepsy is known as a benign and self-limited reflex epilepsy, by firstly avoiding hot water or long showers and secondly using intermittent benzodiazepines or conventional antiepileptic drugs, may be sufficient to be seizure-free.
Hydrocephaly Secondary To Central Vein Thrombosis in a Hemodialysis Patient
(Professional Medical Publications, 2012) Emre, Habib; Soyoral, Yasemin Usul; Erdur, Fatih Mehmet; Begenik, Huseyin; Sayin, Refah
Neurological disorders can be observed in hemodialysis patients due to uremic encephalopathy, electrolyte imbalance, infection, medications, glucose intolerance, hypoxia and psychiatric disorders. We present a case of hydrocephalus consequent to central vein thrombosis that is rarely seen in an adult hemodialysis patient and which causes neuro-psychiatric symptoms.
The Neurological Monitoring and Treatment of a Case Diagnosed With Postpartum Cerebellar Infarction
(Professional Medical Publications, 2012) Sayin, Refah; Kamaci, Mansur; Sahin, Hanim Guler; Kurdoglu, Zehra; Aksin, Serif
A 32-year-old female patient with a'previous history of cesarean section, who was referred to our clinic due to pre-eclampsia, was administered a cesarean section due to fetal distress. Consultation with the Neurologic Department was performed upon the development of complaints including headache, dizziness and blurred vision. Upon detection of acute infarction in the left cerebellar region on cerebral diffusion magnetic resonance imaging (MRI), she was referred to the Neurology Clinic. To investigate the etiology of stroke occurring at an early age, various biochemicals, hematological analyses, vasculitis, infection markers and radiological imaging methods (carotis, vertebral artery color Doppler ultrasonography, cerebral arteriography-venography MR angiography, and cervical MR angiography) were used. Treatment included anti-lipid and anti-aggregant therapies for hypertriglyceridemia and infarction respectively. The patient was discharged upon improvement in her complaints.
Polyneuropathy Due To Cyclosporine a in Patients With Renal Transplantation: a Case Report
(Taylor & Francis Ltd, 2011) Sayin, Refah; Soyoral, Yasemin Usul; Erkoc, Reha
Background: Calcineurin inhibitor cyclosporine A (CsA) is a potent immunosuppressive agent. The side effects of CsA include nephrotoxicity, hypertension, hypertrichosis, infection, hyperpotassemia, and, to a lower extent, neuropathy. Objectives: In this case report, we aimed to present a renal transplant patient with polyneuropathy (PNP) due to the use of CsA and with improvement when switched to rapamycin. Methods: In electromyography, axonal sensory PNP was detected. CsA was stopped and rapamycin was begun. Results: His complaints rapidly improved after using rapamycin. Conclusions: Patients using CsA should be closely monitored for peripheral neuropathy and in case of toxicity, alternative immunosuppressive agents should be considered.
Randomised, Controlled Blink Reflex in Patients With Migraine and Tension Type Headache
(Pakistan Medical Assoc, 2011) Yildirim, Gokhan; Sayin, Refah; Cogen, Etem Emre; Odabas, Faruk Omer; Tombul, Temel
Objectives: To investigate the latencies, amplitudes of R1, R2i and R2k responses and R2 habituation; to compare the groups with each other and with the placebo group and to demonstrate new evidences on migraine and tension-type headache TTH mechanisms. Methods: This analytical study was carried out among 40 migraine patients who were admitted to Yuzuncu Yil University, Medical Faculty, Neurology Clinics between May 2009 and December 2009, with or without aura according to the diagnostic criteria of International Headache Society 2004 classification. Forty TTH patients, who were diagnosed with TTH were included, and 40 control group subjects were formed according to the same demographic data. SPSSv13 was used for Chi-square test, one-way ANOVA and Pearson correlation coefficients was used for the determination of the relation between the groups and categorical. Results: Mean age was 33.04 +/- 9.07 years. An average of RR2k latency was significantly high in migraine group comparing with TTH and the control groups,, and in TTH group comparing with the control group. Similarly, the average of LR2k latency was found to be significantly higher in migraine group than TTH and the control groups, and significantly higher in TTH group than the control group. Conclusion: Our findings demonstrated that brainstem and trigeminovascular connections play an important role in migraine pathogenesis and that central mechanisms play a role in TTH and concerning these two diseases.
The Role of Atrial Fibrillation on Mortality and Morbidity in Patients With Ischaemic Stroke
(Pakistan Medical Assoc, 2013) Cogen, Etem Emre; Tombul, Temel; Yildirim, Gokhan; Odabas, Faruk Omer; Sayin, Refah
Objective: To investigate the impact of atrial fibrillation on mortality and morbidity in ischaemic stroke patients. Methods: The retrospective study was conducted at the Neurology Clinic, Faculty of Medicine, Yuzuncu Yil University, Van, Turkey, and comprised records of ischaemic stroke patients hospitalised between January 2006 and September 2009. SPSS 13 was used for statistical analysis. Results: Of the 404 patients in the study, 69 (17.1%) had atrial fibrilation. The mean age of such patients was 66.78 +/- 12.23 years compared to 61.01 +/- 15.11 years for the rest. Besides 47 (68.1%) of these patients were females. According to the modified Rankin Scale scores, the degree of disability was significantly higher at the time of arrival and discharge, and mortality rates were significantly higher also (p < 0.01). Conclusion: Atrial fibrillation affected the prognosis of ischaemic stroke adversely in terms of mortality and morbidity.
Serum Levels of Trace Elements and Heavy Metals in Patients With Acute Hemorrhagic Stroke
(Springer, 2014) Karadas, Sevdegul; Sayin, Refah; Aslan, Mehmet; Gonullu, Hayriye; Kati, Celal; Dursun, Recep; Demir, Halit
Trace elements are essential components of biological structures, but alternatively, they can be toxic at concentrations beyond those necessary for their biological functions. Changes in the concentration of essential trace elements and heavy metals may affect acute hemorrhagic stroke. The aim of this study was to measure serum levels of essential trace elements [iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), and magnesium (Mg)] and heavy metals [cobalt (Co), cadmium (Cd), and lead (Pb)] in patients with acute hemorrhagic stroke. Twenty-six patients with acute hemorrhagic stroke and 29 healthy controls were enrolled. Atomic absorption spectrophotometry (UNICAM-929) was used to measure serum Fe, Cu, Pb, Cd, Zn, Co, Mn and Mg concentrations. Serum Cd, Pb and Fe levels were significantly higher in patients with acute hemorrhagic stroke than controls (p < 0.001), while serum Cu, Zn, Mg and Mn levels were significantly lower (all p < 0.001). However, there was no significant difference between the groups with respect to serum Co levels (p > 0.05). We first demonstrate increased Cd, Pb, and Fe levels; and decreased Cu, Zn, Mg, and Mn levels in patients with acute hemorrhagic stroke. These findings may have diagnostic and prognostic value for acute hemorrhagic stroke. Further studies are required to elucidate the roles of trace elements and heavy metals in patients with acute hemorrhagic stroke.
Serum Prolidase Enzyme Activity and Oxidative Stress Levels in Patients With Diabetic Neuropathy
(Springer, 2014) Sayin, Refah; Aslan, Mehmet; Kucukoglu, Mehmet Emin; Luleci, Arda; Atmaca, Murat; Esen, Ramazan; Demir, Halit
Previous studies have suggested that prolidase and nitric oxide (NO) regulate many processes, such as collagen synthesis and matrix remodeling. Oxidative stress plays an important role in the development of microvascular complications in diabetic patients. Data on serum prolidase activity in patients with diabetes mellitus or diabetic neuropathy (DN) are limited and conflicting. The aim of this study was to measure serum prolidase activity, NO, total antioxidant status (TAS), and malondialdehyde (MDA) levels in patients with DN. Forty-five patients with DN and 40 healthy controls were enrolled. Serum prolidase activity, TAS, MDA, and NO levels were determined. Serum MDA and NO levels were significantly higher in DN patients than controls (p = 0.002, p = 0.001, respectively), while prolidase activity and TAS levels were lower (p = 0.003, p = 0.001, respectively). Prolidase activity was negatively correlated with NO and MDA (r = -0.911, p < 0.001; r = -0.905, p < 0.001, respectively), while positively correlated with TAS (r = 0.981, p < 0.001) in DN patients. The current study is the first showing the decreased serum prolidase enzyme activity. Our results suggest that decreased collagen turnover may occur in DN patients, who have increased oxidative stress and increased NO levels. Decreased prolidase activity seems to be associated with increased NO levels and oxidative stress along with decreased antioxidant levels in DN. Therefore, decreased prolidase activity may play a role in pathogenesis of DN. Prospective clinical studies are necessary to confirm these findings.