Modeling the Catalytic Activity and Kinetics of Lipase(Glycerol-Ester Hydrolase)

Demirer, Goksel N.,Duran, Metin,Tanner, Robert D. The Korean Society for Biotechnology and Bioengine 1996 Biotechnology and Bioprocess Engineering Vol.1 No.1

In order to design industrial scale reactors and proceises for multi-phase biocatalytic reactions, it is essential to understand the mechanisms by which such systems operate. To il-lustrate how such mechanisms can be modeled, the hydrolysis of the primary ester groups of triglycerides to produce fatty acids and monoglycerides by lipased (glycerol-ester hydrolase) catalysis has been selected as an example of multiphase biocatalysis. Lipase is specific in its behavior such that it can act only on the hydrolyzed (or emulsified) part of the substrate. This follows because the active center of the enzyme is catalytically active only when the substrate contacts it in its hydrolyzed form. In other words, lipase acts only when it can shuttleback and forth between the emulsion phase and the water phase, presumably within an interphase or boundary layer between these two phases. In industrial applications lipase is employed as a fat splitting enzyme to remove fat stains from fabrics, in making cheese, to flavor milk products, and to degrade fats in waste products. Effective use of lipase in these processes requires a fundamental understanding of its kinetic behavior and interactions with substrates under various environmental conditions. Therefore, this study focuses on modeling and simulating the enzymatic activity of the lipase as a step towards the basic understanding of multi-phase biocatalysis processes.

Effects of postoperative parenteral nutrition with different lipid emulsions in patients undergoing major abdominal surgery

Seher Demirer,Ali Sapmaz,Ahmet Serdar Karaca,Ilknur Kepenekci,Semih Aydintug,Deniz Balci,Pinar Sonyurek,Kenan Kose 대한외과학회 2016 Annals of Surgical Treatment and Research(ASRT) Vol.91 No.6

Purpose: This study was designed to investigate the effects of total parenteral nutrition (PN) using different lipid emulsions in patients undergoing major abdominal surgery. Methods: Fifty-two patients were randomized to receive soybean oil + medium chain triglycerides (MCT) (group I), soybean oil + olive oil (group II), soybean oil + olive oil + fish oil (group III) as a lipid source. PN was started on postoperative day 1 and patients were maintained on PN for a minimum period of 4 days. Laboratory variables (CRP, prealbumin, transferrin) were measured before surgery and on postoperative days. Results: Three treatment groups were included in the study. Patients in group I received long chain triglycerides (LCT) + LCT/MCT emulsion (%75 LCT + %25 LCT/MCT); Patients in group II received olive oil based emulsion (80% olive oil + 20% soybean oil, ClinOleic); Patients in group III received fish oil in addition to olive oil based emulsion (%85 ClinOleic + %15 Omegaven; Fresenius Kabi). The following 14 parameters were assessed: body weight, CRP, prealbumin, transferrin, tumor necrosis factor-α, interleukin-6, total antioxidant status, thiobarbituric acid reactive substances, oxidized low density lipoprotein-2, complete blood cell, international normalized ratio, D-dimer, activated partially thromboplastin time, prothrombin time. All other parameters showed no differences among the groups. Conclusion: The results of our trial demonstrate a potential beneficial effect of soybean oil/olive oil based lipid emulsions for use in PN regarding inflammatory response and oxidant capacity in the treatment of patients.

Clinical and Prognostic Features of Erionite-Induced Malignant Mesothelioma

Ersin Demirer,Elamin M. Elamin,Christian F. Ghattas,Mohamed O. Radwan 연세대학교의과대학 2015 Yonsei medical journal Vol.56 No.2

This review analytically examines the published data for erionite-related malignantpleural mesothelioma (E-MPM) and any data to support a genetically predisposedmechanism to erionite fiber carcinogenesis. Adult patients of age ≥18 years with erionite-related pleural diseases and genetically predisposed mechanisms to erionite carcinogenesis were included, while exclusion criteria included asbestos- or tremolite-related pleural diseases. The search was limited to human studies though not limited to a specific timeframe. A total of 33 studies (31042 patients) including 22 retrospective studies, 6 prospective studies, and 5 case reports were reviewed. E-MPM developed in some subjects with high exposures to erionite, though not all. Chest CT was more reliable in detecting various pleural changes in E-MPM than chest X-ray, and pleural effusion was the most common finding in E-MPM cases, by both tests. Bronchoalveolar lavage remains a reliable and relatively less invasivetechnique. Chemotherapy with cisplatin and mitomycin can be administered either alone or following surgery. Erionite has been the culprit of numerous malignantmesothelioma cases in Europe and even in North America. Erionite has a higher degree of carcinogenicity with possible genetic transmission of erionite susceptibilityin an autosomal dominant fashion. Therapeutic management for E-MPM remains very limited, and cure of the disease is extremely rare.

Evaluation of Quality of Life with the Chronic Obstructive Pulmonary Disease Assessment Test in Chronic Obstructive Pulmonary Disease and the Effect of Dyspnea on Disease-Specific Quality of Life in These Patients

OguzhanOkutan,Dilaver Tas,Ersin Demirer,ZaferKartaloglu 연세대학교의과대학 2013 Yonsei medical journal Vol.54 No.5

Purpose: The chronic obstructive pulmonary disease (COPD) assessment test (CAT) was recently introduced for use in assessing disease-specific quality of life and follow-up of patients with COPD. The purpose of this study was to evaluate the effect of the dyspnea on disease-specific quality of life detected by CAT score in patients with COPD. Materials and Methods: In this study, 90 stable patients with COPD as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria were included. The level of dyspnea was assessed with the Medical Research Council (MRC) dyspnea scale, and disease-specific quality of life was assessed with CAT score. Results: The mean±SD age was 68.5±10.9 (range 41-97) years. A significant relationship was established between CAT score, MRC dyspnea scale score and GOLD stage in patients with COPD. There was also a positive correlation between dyspnea scale scores and GOLD stage in the patients (p<0.001), as well as positive correlation between CAT score and dyspnea scale score (p<0.001). CAT score showed a significant correlation with hospitalization and exacerbations (p<0.05). Conclusion: Dyspnea is an important symptom that may impact quality of life in patients with COPD. CAT was shown to be a simple, fast and intelligible measurement of disease-specific quality of life, and was correlated with levels of dyspnea in patients with COPD.

Periodontal Status of Chronic Renal Failure Patients Receiving Hemodialysis

Ismail Marakoglu,Ulvi Kahraman Gursoy,Serhat Demirer,Hafize Sezer 연세대학교의과대학 2003 Yonsei medical journal Vol.44 No.4

Host factors such as systemic diseases, genetic polymorphism or drug usage play a major role in the pathogenesis of periodontal disease by modifying the host response to periodontal infection or altering the susceptibility to infection by periodontal organisms. This study was designed to evaluate the clinical response of patients receiving hemodialysis to existing microbial dental plaque. Gingival Index (GI) and Plaque Index (PI) scores and probing depths (PD) were recorded for the entire dentition on 36 chronic renal failure patients receiving hemodialysis (H) and 36 systemically healthy individuals (C), matched with the patient group, based on age and extent of plaque accumulation. No statistically significant difference was observed in the clinical parameters between the two groups (PI: t=1.69 p= 0.096; GI: t=1.057 p=0.294; PD: t=0.01 p=0.99). In the present study, H patients revealed a similar response to existing bacterial plaque and their periodontal status was comparable to that of the control group. Although patients receiving hemodialysis have been suggested to present a certain degree of immunosuppression, based on the findings of the present study chronic renal failure does not seem to be an additional risk factor for more severe periodontal destruction. Host factors such as systemic diseases, genetic polymorphism or drug usage play a major role in the pathogenesis of periodontal disease by modifying the host response to periodontal infection or altering the susceptibility to infection by periodontal organisms. This study was designed to evaluate the clinical response of patients receiving hemodialysis to existing microbial dental plaque. Gingival Index (GI) and Plaque Index (PI) scores and probing depths (PD) were recorded for the entire dentition on 36 chronic renal failure patients receiving hemodialysis (H) and 36 systemically healthy individuals (C), matched with the patient group, based on age and extent of plaque accumulation. No statistically significant difference was observed in the clinical parameters between the two groups (PI: t=1.69 p= 0.096; GI: t=1.057 p=0.294; PD: t=0.01 p=0.99). In the present study, H patients revealed a similar response to existing bacterial plaque and their periodontal status was comparable to that of the control group. Although patients receiving hemodialysis have been suggested to present a certain degree of immunosuppression, based on the findings of the present study chronic renal failure does not seem to be an additional risk factor for more severe periodontal destruction.

Serum Soluble Urokinase Plasminogen Activator Receptor Levels in Chronic Hepatitis B and C Patients and Relationship with Clinical Parameters

( Ali Pekcan Demiröz ),( Reyhan Öztürk ),( Şener Barut ),( Salih Cesur ),( Semanur Ayyıldız ),( Vildan Fidancı ),( Osman Demir ),( Ferdi Güneş ),( Laser Şanal ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Chronic hepatitis B (CHB) and C (CHC) are leading causes of liver cirrhosis and hepatocellular cancer. Defining of inflammatory activity and severity of disease is important for commencing antiviral treatment and monitoring the patient. Currently noninvasive serological markers to define disease activity are of great interest. In this study we aimed to determine soluble urokinase plasminogen activator receptor (suPAR) levels of patients with CHB and CHC, compare its levels with those of controls and to find if suPAR levels correlated with some laboratory parameters, histologic activity index (HAI) and fibrosis stage. Methods: Twenty-eight patients with CHB, 11 patients with CHC and 41 healthy subjects, eighty subjects in total, were included in the study. suPAR levels of all subjects were determined using commercial ELISA kits according to manufacturer’s instructions. Correlation between suPAR levels and parameters including AST, ALT, leukocyte count, thrombocyte count and liver histology scores were statistically analyzed. Results: Fifty percent of CHB patients were on oral antiviral treatment. Serum suPAR levels of both CHB and CHC patients were higher than controls (p< 0,001). Age, suPAR, HAI, AST, ALT, leukocyte and thrombocyte counts of subjects in different groups (CHB, CHC patients and controls) were shown in table 1. When we divided patients into two groups according to HBV DNA, suPAR levels were not different between patients with HBV DNA >1000 IU/ml and those with HBV DNA<1000 IU/ml. suPAR levels were not found to be correlated with AST, ALT levels, thrombocyte and leukocyte counts or histologic findings. Conclusions: In both CHB and CHC patients, suPAR levels were determined to be higher than healthy controls although suPAR was not found to be correlated with diseae activity or severity related parameters. However new wide scale studies are needed to investigate the relation between suPAR and disease activity or fibrosis stage.

Strengthening of RC beams with prefabricated RC U cross-sectional plates

Demir, Ali,Tekin, Muhammed,Turali, Tezcan,Bagci, Muhiddin Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.6

The topic of this study is to strengthen cracked beams with prefabricated RC U cross-sectional plates. The damaged beams were repaired by epoxy based glue. The repaired beams were strengthened using prefabricated plates. The strengthening plates were bonded to the bottom and side faces of the beams by anchorage rods and epoxy. The strengthened beams were incrementally loaded up to maximum load capacities. The experimental results were satisfactory since the load carrying capacities of damaged beams were increased approximately 76% due to strengthening. It was observed that strengthening plates had a dominant effect on the performance of beams in terms of both the post-elastic strength enhancement and the ductility. The experimental program was supported by a three-dimensional nonlinear finite element analysis. The experimental results were compared with the results obtained from the beam modeled with ANSYS finite element program.

Hormone Receptor, HER2/NEU and EGFR Expression in Ovarian Carcinoma - is here a Prognostic Phenotype?

Demir, Lutfiye,Yigit, Seyran,Sadullahoglu, Canan,Akyol, Murat,Cokmert, Suna,Kucukzeybek, Yuksel,Alacacioglu, Ahmet,Cakalagaoglu, Fulya,Tarhan, Mustafa Oktay Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Purpose: We aimed to evaluate the effects of hormone receptor, HER2, and epidermal growth factor receptor (EGFR) expression on epithelial ovarian cancer (EOC) prognosis and investigate whether or not phenotypic subtypes might exist. Materials and Methods: The medical records of 82 patients who were diagnosed with EOC between 2003 and 2012 and treated by platinum-based chemotherapy were retrospectively evaluated. Expression of EGFR, oestrogen (ER), progesterone (PR), and cerbB2 (HER2) receptors were assessed immunohistochemically on paraffin-embedded tissues of these patients. Three phenotypic subtypes were defined according to ER, PR, and HER2 expression and associations of these with EGFR expression, clinicopathologic features, platinum sensitivity, and survival were investigated. Results: When we classified EOC patients into three subtypes, 63.4% had hormone receptor positive (HR(+)) (considering breast cancer subtypes, luminal A), 18.3% had triple negative, and 18.3% had HER2(+) disease. EGFR positivity was observed in 37 patients (45.1%) and was significantly more frequent with advanced disease (p=0.013). However, no significant association with other clinicopathologic features and platinum sensitivity was observed. HER2(+) patients had significantly poorer outcomes than HER2(-) counterparts (triple negative and HR positive patients) (p=0.019). Multivariate analysis demonstrated that the strongest risk factor for death was residual disease after primary surgery. Conclusions: Triple negative EOC may not be an aggressive phenotype as in breast cancer. The HER2 positive EOC has more aggressive behaviour compared to triple negative and HR(+) phenotypes. EGFR expression is more frequent in advanced tumours, but is not related with poorer outcome. Additional ovarian cancer molecular subtyping using gene expression analysis may provide more reliable data.

THE SNOWFLAKE CURVE AS AN ATTRACTOR OF AN ITERATED FUNCTION SYSTEM

Demir, Bunyamin,Ozdemir, Yunus,Saltan, Mustafa Korean Mathematical Society 2013 대한수학회논문집 Vol.28 No.1

Although the snowflake curve, the boundary of the Koch snowflake, is one of the well-known fractals, there is no iterated function system (IFS) for it in the literature. In this study, we give an IFS for this familiar closed curve.

Effects of Distant Reiki On Pain, Anxiety and Fatigue in Oncology Patients in Turkey: A Pilot Study

Demir, Melike,Can, Gulbeyaz,Kelam, Ayhan,Aydiner, Aydin Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.12

Background: Fatigue, stress and pain are common symptoms among cancer patients, affecting the quality of life. The purpose of the present study was to determine the effect of distant Reiki on pain, anxiety and fatigue in oncology patients. Materials and Methods: Participants in the control group received usual medical and nursing care during their stay. The intervention group received usual care plus five distant Reiki sessions, one each night for 30 min. A face to face interview was performed and patient personal and illness related characteristics were evaluated using the Patient Characteristics form. Pain, stress and fatigue were evaluated according to a numeric rating scale. Results: The experimental group was predominantly composed of women (71.4%), married individuals (40%), and primary school graduates (40%). The control group was predominantly male (72.7%), married (60%), and primary school graduates (60%). The control group demonstrated greater levels of pain (p=0.002), stress (p=0.001) and fatigue (p=0.001). The Reiki group pain score (p <0.0001), stress score (p <0.001) and fatigue score were also significantly lower. Conclusions: The results of this study indicate that Reiki may d ecreasepain, anxiety and fatigue in oncology patients.