Abdurrahman Coskun

Publications (17)33.96 Total impact

• Article: Relationship between pregnancy-associated plasma protein-A and lung cancer.

  Ismet Bulut, Abdurrahman Coskun, Abdullah Ciftci, Erdogan Cetinkaya, Gundeniz Altiay, Tuncay Caglar, Erim Gulcan
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  ABSTRACT: : Pregnancy-associated plasma protein-A (PAPP-A) has insulin-like growth factor (IGF)-dependent IGFBP-4 protease activity and plays an important role in amplifying local IGF-1 activity in wound healing, vascular repair, and bone remodeling. We postulated that PAPP-A may contribute to the availability and activity of IGFs, which affect lung cancer. Therefore, we determined the levels of PAPP-A in patients with lung cancer and their possible clinical significance. : The study population consisted of 83 patients with lung cancer and 33 healthy subjects as a control group. Serum PAPP-A levels were determined using an ultrasensitive enzyme-linked immunosorbent assay. : The serum PAPP-A levels were higher in patients with lung cancer [median (interquartile range) 10.7 (7.6-14.2) ng/mL] than in the control group [6.2 (5.2-9.8) ng/mL, P < 0.001]. There was a significant negative correlation between the serum PAPP-A levels and Karnofsky performance status (r = -0.330; P < 0.001) and a positive correlation with patient age (r = 0.358; P < 0.001). : PAPP-A is a proatherosclerotic metalloproteinase that is also thought to be an inflammatory marker. We found that the serum PAPP-A levels increased in patients with lung cancer and postulated that PAPP-A levels may be a prognostic factor in such cases.
  The American Journal of the Medical Sciences 04/2009; 337(4):241-4. · 1.39 Impact Factor
• Article: The effect of different preparations of hormone therapy on tumor necrosis factor-alpha levels in women with surgical menopause.

  Asli Somunkiran, Abdurrahman Coskun, Fuat Demirci, Oguz Yucel
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  ABSTRACT: The aim of the present prospective controlled study was to examine the influence of 17beta-estradiol and tibolone on tumor necrosis factor-alpha (TNF-alpha) levels in healthy women with surgical menopause. Forty-five surgically menopausal women were included in the study. Thirty women were randomized to receive tibolone 2.5 mg or 17beta-estradiol 2 mg daily for 16 weeks. Fifteen surgically menopausal women who refused hormone therapy served as controls. Serum was collected from the subjects at baseline and at the end of the study for TNF-alpha assay. Neither tibolone nor 17beta-estradiol showed a significant influence on TNF-alpha level at the end of 16 weeks in comparison with baseline. Although tibolone induced a trend toward decreased level of TNF-alpha (3.30 +/- 0.42 vs. 2.56 +/- 1.94 microg/dl), this was non-significant. The slight increase observed in TNF-alpha level in the control group was also insignificant (3.60 +/- 1.20 vs. 4.10 +/- 0.70 microg/dl). Overall, these results demonstrate no significant effects of either tibolone or 17beta-estradiol on circulating TNF-alpha level in surgically menopausal women. However, the significant difference achieved between the tibolone and control group after treatment is promising and needs to be investigated in trials with longer treatment periods.
  Gynecological Endocrinology 03/2008; 24(2):79-83. · 1.58 Impact Factor
• Article: High-sensitivity C-reactive protein levels in cerebrospinal fluid and serum in severe head injury: relationship to tumor necrosis factor-alpha and interleukin-6.

  Merih Is, Abdurrahman Coskun, Galip Zihni Sanus, Taner Tanriverdi, Ali Metin Kafadar, Hakan Hanimoglu, Necmettin Tanriover, Ferruh Gezen, Mustafa Uzan
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  ABSTRACT: Recent studies have demonstrated the role of high-sensitivity C-reactive protein (hsCRP) in inflammatory diseases; however, it is unclear whether this molecule has a role after severe head injury (SHI). Our aim was to evaluate the levels of hsCRP in both cerebrospinal fluid (CSF) and serum from patients after SHI. The study focused on 11 patients with SHI, and evaluated CSF and serum levels of hsCRP, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in a 10-day period following the head trauma. The values were compared with those from nine control patients, who had normal pressure hydrocephalus. In the CSF and serum of the patients after SHI, HsCRP was found to be significantly higher, at all times, than in the controls; TNF-alpha and IL-6 levels were also higher in these patients. However, hsCRP levels did not correlate with either TNF-alpha or IL-6. TNF-alpha and IL-6 increased during the period immediately following the SHI, and intrathecal levels were always higher than those of the serum. This study demonstrates for the first time that hsCRP reaches high levels in both CSF and serum in patients with SHI, and it may therefore be used as an inflammatory index. This finding suggests a need for further studies in this area, which are larger in scope than the present study.
  Journal of Clinical Neuroscience 01/2008; 14(12):1163-71. · 1.25 Impact Factor
• Article: Prolonged elevation of magnesium in the cerebrospinal fluid of patients with severe head injury.

  Ali Metin Kafadar, Galip Zihni Sanus, Merih Is, Abdurrahman Coskun, Taner Tanriverdi, Hakan Hanimoglu, Mustafa Uzan
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  ABSTRACT: Several works have investigated the role of serum magnesium (Mg) concentrations in traumatic brain injury. However, there is restricted information about cerebrospinal fluid (CSF) levels of Mg in patients with severe head injury (SHI). We assessed the changes of Mg concentrations in CSF and serum in patients with SHI during the first 10 days after the trauma. Eleven patients with SHI were studied prospectively on days 1-3, 5 and 10 with analysis of CSF and serum levels of Mg and Ca. The control group consisted of nine patients with hydrocephalus. CSF levels of Mg were significantly higher in patients than controls in the corresponding time points except on days 5 and 10 of trauma. The CSF Mg levels tended to decrease and the highest level was found on day 1 after trauma (2.81 +/- 0.65 mg/dl). In the control group, the CSF level of Mg was 1.95 +/- 0.66 mg/dl. No significant difference can be detected between controls and patients regarding serum Mg and Ca levels. In addition, significantly higher values of Ca in the CSF were observed in all time points after trauma in patients with SHI than in the controls. There was no correlation between the CSF and serum levels of Mg and Ca levels. Our study demonstrates that in patients with SHI, CSF levels of Mg and Ca are elevated during the whole observation period. Further works should be designed in order to show the role and importance of CSF levels of ionized Mg in outcome of patients with SHI.
  Neurological Research 01/2008; 29(8):824-9. · 1.52 Impact Factor
• Article: Do Turkish adults really have lower serum levels of high-density lipoprotein cholesterol?

  Sadik Duran, Ramazan Memisogullari, Abdurrahman Coskun, Ozlem Yavuz, Hatice Yuksel
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  ABSTRACT: Coronary heart disease is the leading cause of death in Turkey. The Turkish Heart Study and TEKHARF study have been carried out at various times and in different parts of Turkey and have suggested that the Turkish population has a low high-density lipoprotein-cholesterol (HDL-C) level. However, in our daily practice, mean HDL-C levels were not as low as previously reported. Here, we investigated the lipid profile, especially the HDL-C level, in the population of the Duzce region of northwest Turkey. Serum triglyceride, total cholesterol, and HDL-C levels were measured in 674 healthy volunteers (398 women and 276 men); low-density lipoprotein cholesterol (LDL-C) levels were calculated using the Friedewald equation. The mean serum HDL-C level was 46.1 +/- 9.8 mg/dl in men and 53.2 +/- 10.7 mg/dl in women; these values are higher than expected based on the Turkish Heart Study. The mean serum total cholesterol level was 196.7 +/- 43.2 mg/dL in men and 198.4 +/- 43.9 mg/dL in women; the mean LDL-C level was 119.6 +/- 34.9 mg/dL in men and 118.7 +/- 34.1 mg/dL in women; and the mean serum triglyceride level was 151.4 +/- 80.9 mg/dL in men and 132.1 +/- 68.9 mg/dL in women. Our finding that the HDL-C level in this population was higher than the previously reported levels in Turkey indicates that HDL-C levels may not be as low as previously thought. We believe that lower HDL-C levels that were previously reported might be due to the difference between techniques of analysis, nutritional status, and percent of subjects who were fasting in the day of analysis or improper subject inclusion which did not reflect the Turkish population causing selection bias.
  Acta cardiologica 11/2007; 62(5):453-9. · 0.61 Impact Factor
• Article: Does l-carnitine have any effect on cold preservation injury of non-fatty liver in the University of Wisconsin solution?

  Abdurrahman Coskun, Omer Gunal, Ibrahim Sahin, Arif Aslaner, Umran Yildirim, Ozlem Yavuz
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  ABSTRACT: Aim: To evaluate the protective effect of l-carnitine on liver tissue preserved in University of Wisconsin (UW) solution. Methods: Twenty Wistar Albino rats were divided into two groups, a control (UW) group and a UW plus l-carnitine group. Retrieved liver grafts were preserved in UW and UW plus l-carnitine solutions at +4 degrees C. Preservation solution samples were assessed at 2, 24, 36, and 48 h to measure alanine aminotransferase and acid phosphatase activity. Tissue injury was scored on paraffin sections. Results: No micro or macrovacuolar fat droplets were observed in the tissue slices. l-Carnitine effectively decreased enzyme release when added to UW solution (P < 0.05). Conclusion: In addition to fatty liver, l-carnitine might be a metabolic adjunct in preservation solutions for non-fatty liver within UW solution.
  Hepatology Research 09/2007; 37(8):656-60. · 2.20 Impact Factor
• Article: Is there a relationship between cord blood pregnancy-associated plasma protein-A and birth weight and length?

  Dursun A Senses, Abdurrahman Coskun, Mine Kiseli, Murat Berberoglu, Omer Kandemir, Serdar Yalvac, Sadik Duran
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  ABSTRACT: Infants whose mothers had low serum pregnancy-associated plasma protein-A (PAPP-A) in the first trimester were observed to have intrauterine growth retardation. Suggesting that PAPP-A plays an important role in the availability and activity of insulin-like growth factors (IGFs), which affect growth, we aimed to investigate cord blood PAPP-A levels of infants with different birth lengths and weights. STUDY DESIGN AND OUTCOME MEASURES: The study included 97 full-term, live-birth neonates. After birth, their lengths and weights were measured. Cord blood PAPP-A levels were measured with an ultra sensitive enzyme-linked immunosorbent assay (ELISA). There was a significant negative correlation between cord blood PAPP-A levels and birth weight (r=-0.23; P=0.023) and length (r=-0.24; P=0.016). Using the classification made according to their length, it was found that newborns with short lengths had significantly higher mean PAPP-A levels than neonates with normal and long lengths (P=0.022; P=0.002, respectively), whereas the difference between infants with normal lengths and infants with long lengths was not found to be statistically significant (P>0.05). On the other hand, there was a difference between the mean PAPP-A levels of the neonate groups classified according to weight; however, these differences were not statistically significant (P>0.05). We concluded that increased cord blood PAPP-A levels were associated with birth length and weight decreases; however, PAPP-A levels affected birth length more than birth weight.
  Early Human Development 08/2007; 83(7):479-82. · 2.05 Impact Factor
• Article: High serum homocysteine levels correlate with a decrease in the blood flow velocity of the ophthalmic artery in highway toll collectors.

  Ramazan Memişoğullari, Harun Yüksel, Abdurrahman Coskun, Hatice Kurt Yüksel, Omer Yazgan, Cahit Bilgin
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  ABSTRACT: Highway workers, such as policemen, automotive service companies, and toll collectors, are placed at risk of the accelerated atherosclerotic process, since recent studies have suggested that exposure to exhaust particles and ambient air pollution increases carotid intima-media thickness and reduces ocular blood flow velocity. Therefore, we assessed the relationship between serum homocysteine, a potential parameter for atherosclerosis, and the ocular blood flow velocity and the resistivity index in highway toll collectors. The peak systolic and end diastolic flow velocities and the resistivity index were measured in 22 toll collectors and 24 control subjects by color Doppler ultrasonography. The resistivity index, which is an indirect measure of the atherosclerotic process, was calculated: resistivity index = (peak systolic velocity - end diastolic velocity)/peak systolic velocity. Serum homocysteine levels were determined by fluorometric high-performance liquid chromatography. In the highway toll collectors, the serum homocysteine level (14.4 +/- 4.8 micromol/l; p < 0.005) and the resistivity index of the ophthalmic artery (0.741 +/- 0.015; p < 0.05) were higher and the ophthalmic blood flow velocity (33.0 +/- 3.0 cm/s; p < 0.001) was lower than those in the controls (10.6 +/- 3.1 micromol/l; 0.728 +/- 0.023; 36.8 +/- 2.2 cm/s; respectively). There were significant correlations between the serum homocysteine level and ophthalmic artery resistivity index in both highway toll collectors (p < 0.001) and controls (p < 0.005). Exposure to exhaust particles might increase the serum homocysteine level, which in turn could lead to the decreased ocular blood flow and the increased resistivity index.
  The Tohoku Journal of Experimental Medicine 07/2007; 212(3):247-52. · 1.24 Impact Factor
• Article: Six Sigma and laboratory consultation.

  Abdurrahman Coskun
  Clinical Chemistry and Laboratory Medicine 02/2007; 45(1):121-3. · 2.15 Impact Factor
• Article: Pregnancy-associated plasma protein A in dialysis patients.

  Abdurrahman Coskun, Zerrin Bicik, Sadik Duran, Aytekin Alcelik, Zeki Soypacaci, Ozlem Yavuz, Sukru Oksuz
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  ABSTRACT: Pregnancy-associated plasma protein A (PAPP-A) was recently described as a new marker of cardiovascular events and of inflammation in uremic patients. The aim of this study was to determine levels of PAPP-A in chronic dialysis patients and its possible relationships with renal osteodystrophy. A total of 99 adult chronic hemodialysis patients, 14 peritoneal dialysis patients and 41 control subjects were included in the study. Serum PAPP-A, intact parathormone (iPTH), calcium, phosphorus and alkaline phosphatase (ALP) were measured. The correlations between PAPP-A and iPTH, calcium, phosphorus and ALP were determined. PAPP-A levels were significantly higher in peritoneal dialysis [4.5 (3.2-6.7) mU/L, median (interquartile range)], and hemodialysis patients [4.7 (3.8-6.5) mU/L] in comparison to control subjects [3.4 (3.0-5.0) mU/L] (p<0.05). In hemodialysis patients, post-dialysis PAPP-A levels [6.2 (4.7-9.4) mU/L] were significantly higher than pre-dialysis levels [4.7 (3.8-6.5) mU/L] (p<0.05). There was a weak but statistically significant positive correlation between serum PAPP-A and iPTH (r=0.216; p=0.041) and ALP (r=0.205; p=0.044) in the hemodialysis group. Correlation between the duration of dialysis therapy and PAPP-A levels was also significant (r=0.267; p=0.008) in the hemodialysis group. PAPP-A levels are elevated in acute coronary syndromes and are closely related to inflammation and oxidative stress. We conclude that PAPP-A levels are increased in dialysis patients and may reflect a greater degree of chronic inflammation than osteodystrophy in uremic patients.
  Clinical Chemistry and Laboratory Medicine 02/2007; 45(1):63-6. · 2.15 Impact Factor
• Source

  Available from: clinchem.org

  Article: Six Sigma and calculated laboratory tests.

  Abdurrahman Coskun
  Clinical Chemistry 05/2006; 52(4):770-1. · 7.91 Impact Factor
• Article: Modified Levey-Jennings charts for calculated laboratory tests.

  Abdurrahman Coskun
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  ABSTRACT: In clinical laboratories, many test results such as low-density lipoproteins can be calculated using the results of specifically measured tests. However, quality control programs deal with only measured tests and there is no quality control procedure for calculated tests. I aimed to modify the Levey-Jennings chart for calculated tests as part of a total quality system. I developed a method using a Taylor series expansion and alternative equations to obtain the standard deviation of calculated tests and then prepared Levey-Jennings charts for these tests. Preparation of Levey-Jennings charts for low-density lipoproteins (and other calculated tests) was simple, and using this chart increased the reliability of calculated test results. Checking only measured tests by quality control procedures before reporting patient results may be inadequate. Preparation of Levey-Jennings charts for calculated tests as part of total quality management will increase the reliability of test results.
  Clinical Chemistry and Laboratory Medicine 02/2006; 44(4):387-90. · 2.15 Impact Factor
• Article: Westgard multirule for calculated laboratory tests.

  Abdurrahman Coskun
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  ABSTRACT: In clinical laboratories, many test results such as low-density lipoprotein (LDL)-cholesterol can be calculated using the results of specifically measured tests. However, quality control programs deal only with measured tests and there is no adequate quality assessment procedure for calculated tests. I aimed to apply the Westgard multirule to calculated tests as a part of routine quality procedures. I prepared a Levey-Jennings chart for calculated tests and all their measured components (Equation chart) and then applied the Westgard multirule to these tests. Applying the Westgard multirule to calculated LDL-cholesterol (and other calculated tests) was simple, and increased the reliability of the results of the calculated tests. Checking the reliability of only measured tests by quality control procedures before reporting patient results may be inadequate. Applying the Westgard multirule to calculated tests as part of total quality management will increase the reliability of test results.
  Clinical Chemistry and Laboratory Medicine 02/2006; 44(10):1183-7. · 2.15 Impact Factor
• Article: The reliability of calculated laboratory results.

  Abdurrahman Coskun
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  ABSTRACT: In clinical laboratories, patient results can be obtained in two ways: (i) by direct determination of requested tests using various chemical methods, (ii) by calculation of unknown test results, based on relationships between measured tests. The reliability of measured tests can be checked by various quality control rules. However, no test is performed to check the reliability of calculated data. In this study we develop a method using Taylor series expansion and an alternative equation to obtain the standard deviation of calculated laboratory tests and discuss the reliability of calculated data. To obtain reliable test results by calculation instead of being measured by chemical methods, the standard deviation of each measured component of the equation must be thoroughly analyzed and then the standard deviation of the equation must be determined. We conclude that the analytical coefficient of variation of any measured component must be lower so as to obtain an acceptable analytical coefficient of variation for calculated tests. Otherwise we should measure the concentration of requested tests by chemical methods instead of calculation by equation using specified components.
  Clinical Chemistry and Laboratory Medicine 02/2005; 43(8):880-2. · 2.15 Impact Factor
• Source

  Available from: duzce.edu.tr

  Article: Pregnancy-associated plasma protein-A and asthma.

  Abdurrahman Coskun, Oner Balbay, Sadik Duran, Ali Nihat Annakkaya, Ismet Bulut, Ozlem Yavuz, Emel Kurt
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  ABSTRACT: Pregnancy-associated plasma protein-A (PAPP-A) is potentially a proatherosclerotic metalloproteinase and a new inflammatory marker. Investigators sought to evaluate the significance of PAPP-A in patients with asthma. Blood samples were collected from 35 patients and 20 control subjects. Serum PAPP-A was determined by enzyme-linked immunosorbent assay. PAPP-A levels of patients with asthma (8.1+/-5.0 mU/L) were higher than those of the control group (4.9+/-2.1 mU/L) (P<.01). A significant correlation was noted between serum PAPP-A concentration and asthma severity (r=.581; P<.01). Investigators concluded that PAPP-A may contribute to airway smooth muscle hyperplasia as an insulin-like growth factor-dependent insulin-like growth factor-binding protein-4 protease in patients with asthma.
  Advances in Therapy 24(2):362-7. · 2.11 Impact Factor
• Article: Does pregnancy-associated plasma protein A have a role in allergic rhinitis?

  Ender Güçlü, Abdurrahman Coskun, Abdurrahman Tokmak, Sadik Duran, Ozcan Oztürk, Nermin Akkan, Erol Egeli
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  ABSTRACT: Pregnancy-associated plasma protein A (PAPP-A), also known as insulin-like growth factor binding protein 4 protease, is postulated to be a new inflammatory marker in various clinical situations such as cardiovascular events, dialysis, renal transplantation, and asthma. PAPP-A also is produced in high concentrations by trophoblasts during pregnancy. We evaluated PAPP-A levels in allergic rhinitis patients and compared these with levels in healthy subjects. Thirty-one newly diagnosed allergic rhinitis patients and 29 healthy controls were included in the study. Serum PAPP-A, IgE, urea, creatinine, aspartate aminotransferase, creatine kinase (CK), CK-MB isoenzyme, total cholesterol, and triglyceride levels were determined. The serum PAPP-A level was significantly higher (p = 0.013) in the allergic rhinitis group (6.1 +/- 2.9 mU/L) than in the control group (4.5 +/- 1.7 mU/L). The PAPP-A level in patients with allergic rhinitis and asthma (6.1 +/- 2.3 mU/L) was not significantly different (p = 0.959) from that in patients with allergic rhinitis alone (6.1 +/- 3.3 mU/L). The serum PAPP-A level in allergic rhinitis patients who had turbinate hypertrophy (6.9 +/- 2.2 mU/L) had a tendency to be higher than that in patients who had no turbinate hypertrophy (5.5 +/- 3.2 mU/L); however, this difference was not statistically significant (p = 0.151). Increased PAPP-A activity may be involved in the inflammation and tissue remodelling that occurs in allergic rhinitis.
  American Journal of Rhinology 22(3):219-22. · 1.36 Impact Factor
• Article: High-sensitivity C-reactive protein levels in cerebrospinal fluid and serum in severe head injury: Relationship to tumor necrosis factor-α and interleukin-6

  Merih Is, Abdurrahman Coskun, Galip Zihni Sanus, Taner Tanriverdi, Ali Metin Kafadar, Hakan Hanimoglu, Necmettin Tanriover, Ferruh Gezen, Mustafa Uzan
  [show abstract] [hide abstract]
  ABSTRACT: Recent studies have demonstrated the role of high-sensitivity C-reactive protein (hsCRP) in inflammatory diseases; however, it is unclear whether this molecule has a role after severe head injury (SHI). Our aim was to evaluate the levels of hsCRP in both cerebrospinal fluid (CSF) and serum from patients after SHI. The study focused on 11 patients with SHI, and evaluated CSF and serum levels of hsCRP, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in a 10-day period following the head trauma. The values were compared with those from nine control patients, who had normal pressure hydrocephalus. In the CSF and serum of the patients after SHI, HsCRP was found to be significantly higher, at all times, than in the controls; TNF-α and IL-6 levels were also higher in these patients. However, hsCRP levels did not correlate with either TNF-α or IL-6. TNF-α and IL-6 increased during the period immediately following the SHI, and intrathecal levels were always higher than those of the serum. This study demonstrates for the first time that hsCRP reaches high levels in both CSF and serum in patients with SHI, and it may therefore be used as an inflammatory index. This finding suggests a need for further studies in this area, which are larger in scope than the present study.
  Journal of Clinical Neuroscience.