Can Erzik | Marmara University (original) (raw)

Papers by Can Erzik

Naunyn-Schmiedeberg's archives of pharmacology, May 15, 2024

Capecitabine is recommended as one of the first-line chemotherapy treatments for advanced or meta... more Capecitabine is recommended as one of the first-line chemotherapy treatments for advanced or metastatic colorectal cancer. Researches have been conducted on capecitabine's impact on the viability of human colon cancer cells and its potential to induce apoptosis. However, even in cases initially responsive to treatment, the development of acquired resistance significantly limits its efficacy. Challenges still exist in effectively treating patients with chemotherapy, and developing new cytotoxic drugs is hindered by drug resistance. Fisetin alters the cell cycle, inducing apoptosis, inhibiting cancer cell proliferation, and enhancing the therapeutic effectiveness of chemotherapy drugs. This work aims to create a plan for reversing capecitabine resistance. For this purpose, the role of capecitabine and/or fisetin combinations in cell proliferation and apoptosis has been determined in both wild-type and capecitabine-resistant HT29 cells (CR/HT29). We developed capecitabine-resistant cell line from wild-type HT29 cells. This study demonstrated the effects of capecitabine, fisetin, and their combinations on both resistant and wild-type cells through experiments including cell survival skills, cell proliferation, wound healing, colony formation, hoechst staining, and western blot analysis. We established capecitabine-resistant cell lines. P-gp expression increased in CR/HT29 cells. Capecitabine effects on a CR/HT29 cells less than wild-type HT29 cells. The combination of fisetin and capecitabine in cell proliferation caused greater reductions in wild-type HT29 cells than in capecitabine-resistant cells. Fisetin has also additive effects on the apoptotic pathway in CR/HT29 cells. This study provides new perspectives on the combination of capecitabine and/or flavonoid treatment in resistant cells. Keywords Capecitabine-resistance • HT29 cell • Fisetin • Apoptosis • Wound-healing Highlights • Fisetin reduces capecitabine resistance in HT29 cell proliferation. • P-gp expression increases in CR/HT29 cells. • Fisetin slows down HT29 cell migration.

DergiPark (Istanbul University), May 20, 2014

As the population ages, it is important to recognize the health problems of the elderly in relati... more As the population ages, it is important to recognize the health problems of the elderly in relation to individual and public health issues. Our aim was to determine the daily habits and health-related behaviours of an aging population concerning factors such as nutritional status, physical and social activity levels and chronic health problems. Patients and Methods: This is a cross-sectional study. The study included 175 participants over 60 years of age that were mentally healthy and living in different nursing homes. A minimental test, a study questionnaire, a geriatric depression scale and an activities of daily living (ADL, physically dependent on others) scale were applied to the participants face to face. Results: Eighty-five (48.6%) of the participants were male. 42.3% of the participants did not do any regular physical exercise in their life time. The frequency of regular physical exercise was higher in the physically non-dependent to others (p=0.005) group in the ADL scale. Depression and ADL scores increased with increasing body mass index (BMI) (p= 0.012 and p= 0.010, respectively). In continuous medication users depression is quite high when compared to those who do not use medication constantly (p= 0.002). With increasing working years, there was a tendency to a decrease in scores of the physically dependent on others group in ADL. Conclusion: Regular physical exercise and an active work history both have a negative correlation on dependency in ADL in later years. Depression is more common among individuals who are on medication due to chronic health problems. A greater BMI was related to a higher frequency of depression and to dependency in ADL.

Gastroenterology, May 1, 2023

Marmara Medical Journal, 2000

Journal of the American Podiatric Medical Association, Mar 1, 2006

A 19-year-old woman presented with pain at the lateral side of the fifth toe of her left foot, wh... more A 19-year-old woman presented with pain at the lateral side of the fifth toe of her left foot, which was separated from the adjacent toe. Initial examination suggested dislocation of the fifth metatarsophalangeal joint due to a past fracture. Radiographs showed a mass arising from the proximal phalanx of the little toe, with no medullary and cortical continuity. Excisional biopsy of the mass was performed, and a histologic diagnosis of bizarre parosteal osteochondromatous proliferation of bone (Nora’s lesion) was made. (J Am Podiatr Med Assoc 96(2): 158–161, 2006)

Turkish Neurosurgery, 2023

AIM: Niacin is a water-soluble vitamin. The effects of niacin on inflammation, oxidative stress a... more AIM: Niacin is a water-soluble vitamin. The effects of niacin on inflammation, oxidative stress and apoptotic processes observed after mild traumatic brain injury (TBI) were studied in this study. MATERIAL and METHODS: Wistar albino male rats were randomly divided into control (n=9), TBI + Placebo group (n=9), TBI + niacin (500 mg/kg; n=7) groups. Mild TBI was performed under anesthesia by dropping a 300 g weight from a height of 1 meter onto the skull. Behavioral tests were applied before and 24 hours after TBI. Luminol and lucigenin levels and tissue cytokine levels were measured. Histopathological damage was scored in brain tissue. RESULTS: After mild TBI, luminol (p<0.001) and lucigenin (p<0.001) levels were increased, and their levels were decreased with niacin treatment (p<0.01-p<0.001). An increased score was obtained with trauma in the tail suspension test (p<0.01), showing depressive behavior. The number of entries to arms in Y-maze test were decreased in TBI group compared to pre-traumatic values (p<0.01), while discrimination (p<0.05) and recognition indices (p<0.05) in object recognition test were decreased with trauma, but niacin treatment did not change the outcomes in behavioral tests. Levels of the anti-inflammatory cytokine IL-10 were decreased with trauma (p<0.05) and increased with niacin treatment (p<0.05). The histological damage score (p<0.001) was increased with trauma, and decreased with niacin treatment in the cortex (p<0.05) and hippocampal dentate gyrus region (p<0.01). CONCLUSION: Niacin treatment after mild TBI inhibited trauma-induced production of reactive oxygen derivatives and elevated the anti-inflammatory IL-10 level. Niacin treatment ameliorated the histopathologically evident damage.

European Journal of Pediatrics, Nov 25, 2019

Although physiologic and neurologic consequences of micronutrient deficiencies have been addresse... more Although physiologic and neurologic consequences of micronutrient deficiencies have been addressed extensively, less is known about their impact on developing gut microbiota. Vitamin B12 deficiency is a common micronutrient deficiency in infants. We aimed to analyze the gut microbial composition of exclusively breastfed infants aged between 4 and 6 months with and without vitamin B12 deficiency by 16S rRNA gene sequencing. In a subgroup of infants with vitamin B12 deficiency, stool samples are recollected and reanalyzed after vitamin B12 supplementation. A total of 88 infants' stool samples (median age 4 months [IQR 4-5], 50% males) were analyzed, of which 28 (31.8%) were vitamin B12 sufficient and 60 (68.2%) were vitamin B12 insufficient. Comparisons between vitamin B12-sufficient and vitamin B12-insufficient infants revealed no evidence of differences in the microbiota. Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes were the most abundant phyla in all groups. There was no difference between the pre-and post-treatment composition of gut microbiota. Conclusion: Vitamin B12-deficient infants have similar gut microbial composition as vitamin B12-sufficient infants. Since the samples were collected at an early period of life and the exposure to deficiency was relatively short, it may be possible that the effects were not fully established. What is Known: • Vitamin B12 is an essential vitamin for humans and also a crucial compound for human gut microbiota. • Vitamin B12 deficiency is common in exclusively breastfed infants. • In contrast to the adult gut microbiota, infant gut microbiota has been shown to have decreased capacity for de novo synthesis of vitamin B12 and depend on dietary source of vitamin B12. What is New: • There is no difference in the gut microbial composition of vitamin B12-deficient and vitamin B12-sufficient infants.

Inflammation, Dec 3, 2008

To evaluate the role of ALA treatment on the healing of acetic acid-induced gastric ulcer, rats w... more To evaluate the role of ALA treatment on the healing of acetic acid-induced gastric ulcer, rats were given ALA (35 mg/kg/day) or saline for 3 days before the induction of ulcer and the treatment was continued twice daily for 2 days (early) or 10 days (late) until they were decapitated. Gastric ulcer index, microscopic score, elevated DNA fragmentation and chemiluminescence levels of the saline-treated ulcer groups were all reduced by ALA treatment. Likewise, ALA treatment inhibited chemiluminescence levels in both early and late ulcer groups. Marked reduction in glutathione levels of the saline-treated early ulcer group was reversed by ALA treatment, while ALA treatment was effective in depressing gastric myeloperoxidase activity in the late ulcer group. In conclusion, ALA treatment shows protective role in the healing of acetic acid-induced gastric injury in rats via the suppression of neutrophil accumulation, preservation of endogenous glutathione, inhibition of reactive oxidant generation and apoptosis.

Cardiology, 2006

Effect of hormone replacement (HRT) therapy on plasma lipoproteins and apolipoproteins, endotheli... more Effect of hormone replacement (HRT) therapy on plasma lipoproteins and apolipoproteins, endothelial function and myocardial perfusion in postmenopausal women with estrogen receptor-α (ER-α) IVS1–397 C/C genotype and established coronary artery disease. Background/Aims: Associations between various ER-α polymorphisms and clinical phenotypes have been studied, including lipid levels and coronary atherosclerosis. We studied 48 postmenopausal women to determine the effect of ER-α IVS1–397 polymorphism on the response to treatment with HRT. Methods: The study had a randomized, double-blind, placebo-controlled and crossover design. Patients were divided into two groups according to ER-α IVS1–397 polymorphism: CC genotype (n = 9); CT or TT genotype (n = 39). HRT was given continuously for 4 weeks, with 4-week washout periods between the treatment periods. Brachial artery Doppler and Tl-201 scintigraphy were performed at the end of each treatment period. Results: HRT lowered total cholesterol, LDL-c and Apo-B levels from baseline values (all p < 0.05) and to a similar degree in CC and CT/TT genotype patients. HRT increased estradiol, HDL-c and Apo A-1 levels relative to baseline values, but to a greater degree in CC patients (p = 0.04, 0.05 and 0.04 by ANOVA, respectively). HRT increased peak forearm blood flow, brachial artery diameter during reactive hyperemia and endothelium-dependent dilation in both groups, but to a greater degree in CC patients (p = 0.03, 0.03 and 0.04 by ANOVA, respectively). Summed stress and rest scores were also more markedly reduced in CC patients (p = 0.04 and 0.05, respectively). The increase in estradiol levels was strongly correlated with the improvement in endothelium-dependent dilation (r = 0.66, p < 0.01), which in turn showed negative correlation with summed stress (r = –0.62, p < 0.01) and rest scores (r = –0.52, p < 0.05) in the CC genotype group. Conclusion: These data suggest that the improvement in endothelium-dependent dilation and the reduction in perfusion abnormalities by increasing estradiol levels with HRT in postmenopausal women with coronary artery disease may differ with respect to different genotypes, the effect being more prominent in those patients with ER-α IVS1–397 CC genotype.

Research Square (Research Square), Apr 14, 2023

Research Square (Research Square), May 7, 2021

Background: Plasminogen activator inhibitor-1 (PAI-1) antagonists are known for their neuroprotec... more Background: Plasminogen activator inhibitor-1 (PAI-1) antagonists are known for their neuroprotective effects. In this study, it was aimed to investigate the possible protective effects of PAI-1 antagonists in a rat mild traumatic brain injury (TBI) model. Method: Sprague Dawley male rats were grouped as sham (n=7), TBI (n=9), TBI + PAI-1 antagonist (5 and 10 mg/kg TM5441 and TM5484; n=6-7). Under anesthesia, TBI was induced by dropping a metal 300gram weight from a height of 1 meter on the skull. Before and 24-hour after trauma neurological examination, tail suspension, Y-maze, novel object recognition tests were performed. Twenty-four hours after TBI, the rats were decapitated and activities of myeloperoxidase, nitric oxide release, luminol-and lucigenin-enhanced chemiluminescence were measured. Also, interleukin-1b, interleukin-6, tumor necrosis factor, interleukin-10, tumor growth factor-b, caspase-3, cleaved caspase-3, and PAI levels were measured with the ELISA method in the brain tissue. Brain injury was graded histopathologically following hematoxylin-eosin staining. Western blot and immunohistochemical investigation for low-density lipoprotein receptor, matrix metalloproteinase-3 and nuclear factor-kB were also performed. Data were analyzed using GraphPad Prism 8.0 (GraphPad Software, San Diego, CA, USA) and expressed as means ± SEM. Values of p < 0.05 were considered to be statistically signi cant. Results: Higher levels of myeloperoxidase activity in the TBI group (p<0.05) were found to be suppressed in 5 and 10 mg/kg TM5441 treatment groups (p<0.05-p<0.01). The tail suspension test score was increased in the TBI group (p<0.001), and decreased in all treatment groups (p<0.05-0.001). The histologic damage score was increased statistically signi cantly in the cortex, dentate gyrus, and CA3 regions in the TBI group (p<0.01-0.001), decreased in the treatment groups in the cortex and dentate gyrus (p<0.05-0.001). Conclusion: PAI antagonists, especially TM5441, has antioxidant and anti-in ammatory properties against mild TBI in the acute period. Behavioral test results were also improved after PAI antagonist treatment after mild TBI. Highlights After mild TBI, PAI-1 antagonists TM5441 and TM5484 was used for the rst time in the literature. PAI-1 inhibition reduced oxidative stress, in ammation and neuronal damage in a TBI model. PAI antagonist treatment also improved corticospinal pathway functions and behavioral results.

DergiPark (Istanbul University), Dec 3, 2016

Objective: H enoch S chonlein P urpura (H SP) is the m ost co m m o n benign va scu litis occurri... more Objective: H enoch S chonlein P urpura (H SP) is the m ost co m m o n benign va scu litis occurring during childhoo d. M orbidity and m ortality rates rise w hen there is organ system involvem ent. W e aim ed to re tro sp e ctive ly e va lu a te H SP ca ses in o u r clin ic a ccording to organ involvem ent, clinical and lab o ra to ry findings.

Marmara Medical Journal, May 31, 2022

Objective: The aim of this study is to determine the perceptions, attitudes, and behaviour of med... more Objective: The aim of this study is to determine the perceptions, attitudes, and behaviour of medical students and lecturers regarding the lectures and their effects on students' learning behaviour. Materials and Methods: This was a qualitative study including multi-methods. Researchers observed lecture ambiance and activities in two courses. Lectures were observed and slide-presentations were evaluated. Additionally, in-depth and focus group interviews were conducted. Results: Two researchers attended and observed 75 lectures. The average number of attendees was 51.21. Eighty percent of lecturers did not introduce any activities to attract attention and prepare students for the lecture. Only 12% of lectures were taught interactively. Of the evaluated 43 (69.80%) slide-presentations, sufficient association or integration was not made between clinical and basic sciences. Conclusion: This study revealed that the lectures created negative feelings and thoughts in students and lecturers, and led to undesirable attitudes and behaviour. It is essential to focus on giving interactive lectures which aim at developing reasoning, decisionmaking, and evaluation competencies. The most significant factors determining students' attendance and appraisal of the lectures were related to the preparation of the lecturers, the intensity of the content, integration between basic science and clinical science, and the presentation skills.