Mehmet Özçelik - Academia.edu (original) (raw)
Papers by Mehmet Özçelik
PubMed, May 1, 2013
Background: Preoperative radiotherapy in colorectal cancers is being used as an adjuvant therapy ... more Background: Preoperative radiotherapy in colorectal cancers is being used as an adjuvant therapy with increasing frequency. Postoperative complications in early and late periods in various ratios are reported. It has also been shown that radiation has a delaying effect on wound healing and this effect is dose-dependent. Aim: This study investigated the effects of the Amifostine on healing of the irradiated colonic anastomosis. Materials and methods: 30 female Wistar rats were divided randomly into three groups equally (n=10). Colonic anastomosis were performed to all rats. Group I served as a control. 800 rad abdominopelvic irradiation on the 5th day of preoperation was given to group II and III. Rats in the group III, prior to radiation, were given Amifostine at a dose of 200 mg/kg. On the 5th postoperative day all the rats were sacrificed and the healing of anastomosis was measured with bursting pressure, hydroxyproline levels and histopathological evaluations. Statistical analyses were expressed by analysis of variance (ANOVA) test and p < 0.05 was regarded as significant. Results: In group II, all parameters were found lower compared with control group and Amifostine+Radiation group. As compared with hydroxyproline values and the anastomotic wound healing scores, except group II, no significantly difference were determined between the two other groups. In bursting pressure levels, Group I and III were higher than group II, but not statistically significant (p > 0.05). In group III (Amifostine+Radiation group), the hydroxyproline levels and anastomotic wound healing scores were found significantly higher than group II (p < 0.05), and no significant difference were found between the control group. Conclusions: It is determined that radiation given on the 5th preoperative day has a negative effect on anastomotic wound healing and administered Amifostine prevent this negative effect. In the light of these data, the Amifostine may have a positive effect on preoperative irradiated colonic anastomosis and may play an important role in future on the supporting of the colonic anastomosis.
Turkish Journal of Trauma and Emergency Surgery, 2020
Surgery Today, 1993
Esophagectomy without opening the thoracic cavity--transhiatal esophagectomy--(THE) were performe... more Esophagectomy without opening the thoracic cavity--transhiatal esophagectomy--(THE) were performed in 47 patients with malignant tumors localized at various levels of the esophagus. Pulmonary function studies were performed in all patients and they are categorized as low, moderate, or high risk for probable postoperative pulmonary complications according to the risk category system. Nine of these patients were classified as high risk, seven as moderate risk, and the rest as low risk. In all patients but four, reconstruction was accomplished by using their stomachs as a substitute. In the remaining patient, intestinal continuity was established by a left and right colonic interposition. Three patients were lost in the early postoperative period. Two patients categorized as low risk died from pulmonary thromboembolism and cardiac failure, respectively. One patient categorized in the high risk group died of coronary thrombosis. Postoperative complications included transient hoarseness due to recurrent laryngeal nerve paresis in one patient, right pleural effusion in one patient, pneumothorax in two patients, and thrombophlebitis in one patient. In the high risk patient group, there were no pulmonary complications. This clinical study demonstrated the protective effect of THE in patients with serious pulmonary problems.
American Journal of Surgery, Feb 1, 2004
Turkish Journal of Trauma and Emergency Surgery
Turkish Journal of Colorectal Disease
Turkish Journal of Medical Sciences, 1996
Konuralp Tıp Dergisi, 2021
Objective: To investigate the emergency department admissions, the general surgery consultation r... more Objective: To investigate the emergency department admissions, the general surgery consultation request, and the necessity of immediate treatment of patients despite the fact that the society did not leave the house unless necessary during the pandemic period. Methods: The files of patients who admitted to the emergency department and whose general surgery consultation was requested due to urgent surgical treatment were retrospectively scanned between March-May 2020, which is the Covid 19 pandemic period and March-May 2019, as a time period in which normal social life continues. Age, gender, complaints, comorbid diseases, the necessity of truly emergency surgical treatment as well as the socioeconomic level scale for each individual were recorded and analyzed. Results: The rate of request for consultation was 2.7% (n = 170) in the pandemic period, and 3.1% (n = 316) in the non-pandemic period. In both periods, no statistically significant difference was found in the distribution of ...
Namık Kemal Tıp Dergisi, 2021
Aim: Esophageal cancer is a fatal disease where the majority of patients are diagnosed at an adva... more Aim: Esophageal cancer is a fatal disease where the majority of patients are diagnosed at an advanced stage. In this study, we aimed to present the demographic and clinicopathological characteristics of patients who were operated for esophageal cancer. Materials and Methods: A total of 847 patients who underwent surgery, chemoradiotherapy, or palliative procedures for esophageal pathology between the years of 1985 and 2018 were retrospectively analyzed. Age, gender, tumor location, histopathology, surgical technique, and chemoradiotherapy history of patients were analyzed. Results: In the study, 488 patients were male (60.5%) and 319 were female (39.5%). The ratio of males and females was 1.52. The average age was 58.6 years, and 80.1% were older than 50 years. The most common pathological material obtained was squamous cell carcinoma (67.5%), followed by adenocarcinoma (27.7%). Total esophagectomy was performed in 435 patients; distal esophagectomy was performed in 38 patients. Tra...
Annals of Medical Research, 2021
Anaesthesia, 2021
SummaryPeri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this stu... more SummaryPeri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS‐CoV‐2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre‐operative SARS‐CoV‐2 infection were compared with those without previous SARS‐CoV‐2 infection. The primary outcome measure was 30‐day postoperative mortality. Logistic regression models were used to calculate adjusted 30‐day mortality rates stratified by time from diagnosis of SARS‐CoV‐2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre‐operative SARS‐CoV‐2 diagnosis. Adjusted 30‐day mortality in patients without SARS‐CoV‐2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre‐operative SARS‐CoV‐2 diagnosis, mortality was increased in patients having surgery wi...
British Journal of Surgery, 2021
Background This study aimed to determine the impact of pulmonary complications on death after sur... more Background This study aimed to determine the impact of pulmonary complications on death after surgery both before and during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Methods This was a patient-level, comparative analysis of two, international prospective cohort studies: one before the pandemic (January–October 2019) and the second during the SARS-CoV-2 pandemic (local emergence of COVID-19 up to 19 April 2020). Both included patients undergoing elective resection of an intra-abdominal cancer with curative intent across five surgical oncology disciplines. Patient selection and rates of 30-day postoperative pulmonary complications were compared. The primary outcome was 30-day postoperative mortality. Mediation analysis using a natural-effects model was used to estimate the proportion of deaths during the pandemic attributable to SARS-CoV-2 infection. Results This study included 7402 patients from 50 countries; 3031 (40.9 per cent) underwent surgery be...
Anaesthesia, 2021
SummarySARS‐CoV‐2 has been associated with an increased rate of venous thromboembolism in critica... more SummarySARS‐CoV‐2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri‐operative or prior SARS‐CoV‐2 were at further increased risk of venous thromboembolism. We conducted a planned sub‐study and analysis from an international, multicentre, prospective cohort study of elective and emergency patients undergoing surgery during October 2020. Patients from all surgical specialties were included. The primary outcome measure was venous thromboembolism (pulmonary embolism or deep vein thrombosis) within 30 days of surgery. SARS‐CoV‐2 diagnosis was defined as peri‐operative (7 days before to 30 days after surgery); recent (1–6 weeks before surgery); previous (≥7 weeks before surgery); or none. Information on prophylaxis regimens or pre‐operative anti‐coagulation for baseline comorbidities was no...
British Journal of Surgery, 2021
To support the global restart of elective surgery, data from an international prospective cohort ... more To support the global restart of elective surgery, data from an international prospective cohort study of 8492 patients (69 countries) was analysed using artificial intelligence (machine learning techniques) to develop a predictive score for mortality in surgical patients with SARS-CoV-2. We found that patient rather than operation factors were the best predictors and used these to create the COVIDsurg Mortality Score (https://covidsurgrisk.app). Our data demonstrates that it is safe to restart a wide range of surgical services for selected patients.
… Klinikleri Journal of …, 1997
... 15:48) Ömer Özkan'dan ... 13:23) Twitter'da canlı canlı açık kalp ... Medical Resea... more ... 15:48) Ömer Özkan'dan ... 13:23) Twitter'da canlı canlı açık kalp ... Medical Research Year: 1997 / Volume: 15 / No: 1. Repair Of Stomach Defects By Dehydrated Dura Mater Patch İn The Rat Salih PEKMEZCİ a , M.Faik ÖZÇELİK a , Ediz ALTINLI a , Süha GÖKSEL b , Murat VARDAR ...
Journal of Hepato-Biliary-Pancreatic Surgery, 2002
Journal of Surgical Research, 2008
Background. The aim of this paper is to assess the effects of halofuginone, a specific inhibitor ... more Background. The aim of this paper is to assess the effects of halofuginone, a specific inhibitor of synthesis of collagen Type 1, on fibrogenetic process in an experimental model of early pancreatic fibrosis. Methods. Thirty rats were divided into three equal groups: group 1, sham laparotomy; group 2, severe hyperstimulation and obstruction pancreatitis (SHOP) with no treatment; group 3, SHOP with halofuginone treatment group. SHOP model was induced by complete pancreatic duct obstruction and daily cerulein hyperstimulation (50 g/kg, intraperitoneally). Halofuginone was administered daily from the operative day (5 mg/kg, intraperitoneally). All of the animals were sacrificed, and blood and pancreatic tissue samples were obtained for biochemical and histopathological examination on the 5th postoperative day. Results. No mortality was observed in any group. Serum amylase, lipase, hyaluronic acid, and nitric oxide levels were significantly higher in groups 2 and 3 compared with group 1 (P < 0.05), but were significantly lower in group 3 compared with group 2 (P < 0.05). No significant differences were observed regarding serum malondialdehyde and glutathione levels between groups 1 and 3. Tissue hydroxyproline levels were found to be significantly higher in groups 2 and 3 compared with group 1 (P < 0.001), but were significantly lower in group 3 compared with group 2 (P < 0.001). Although tissue hydroxyproline levels were significantly higher in the halofuginone treatment group compared with the control group, histopathological evaluation did not reveal a significant difference between these groups regarding collagen deposition. When group 3 was compared with group 2, halofuginone significantly reduced inflammation and acinar atrophy in the pancreas as well (P < 0.05). Conclusion. Halofuginone was found to be effective in reducing SHOP-related inflammation, acinar atrophy, and fibrosis in the pancreas.
PubMed, May 1, 2013
Background: Preoperative radiotherapy in colorectal cancers is being used as an adjuvant therapy ... more Background: Preoperative radiotherapy in colorectal cancers is being used as an adjuvant therapy with increasing frequency. Postoperative complications in early and late periods in various ratios are reported. It has also been shown that radiation has a delaying effect on wound healing and this effect is dose-dependent. Aim: This study investigated the effects of the Amifostine on healing of the irradiated colonic anastomosis. Materials and methods: 30 female Wistar rats were divided randomly into three groups equally (n=10). Colonic anastomosis were performed to all rats. Group I served as a control. 800 rad abdominopelvic irradiation on the 5th day of preoperation was given to group II and III. Rats in the group III, prior to radiation, were given Amifostine at a dose of 200 mg/kg. On the 5th postoperative day all the rats were sacrificed and the healing of anastomosis was measured with bursting pressure, hydroxyproline levels and histopathological evaluations. Statistical analyses were expressed by analysis of variance (ANOVA) test and p < 0.05 was regarded as significant. Results: In group II, all parameters were found lower compared with control group and Amifostine+Radiation group. As compared with hydroxyproline values and the anastomotic wound healing scores, except group II, no significantly difference were determined between the two other groups. In bursting pressure levels, Group I and III were higher than group II, but not statistically significant (p > 0.05). In group III (Amifostine+Radiation group), the hydroxyproline levels and anastomotic wound healing scores were found significantly higher than group II (p < 0.05), and no significant difference were found between the control group. Conclusions: It is determined that radiation given on the 5th preoperative day has a negative effect on anastomotic wound healing and administered Amifostine prevent this negative effect. In the light of these data, the Amifostine may have a positive effect on preoperative irradiated colonic anastomosis and may play an important role in future on the supporting of the colonic anastomosis.
Turkish Journal of Trauma and Emergency Surgery, 2020
Surgery Today, 1993
Esophagectomy without opening the thoracic cavity--transhiatal esophagectomy--(THE) were performe... more Esophagectomy without opening the thoracic cavity--transhiatal esophagectomy--(THE) were performed in 47 patients with malignant tumors localized at various levels of the esophagus. Pulmonary function studies were performed in all patients and they are categorized as low, moderate, or high risk for probable postoperative pulmonary complications according to the risk category system. Nine of these patients were classified as high risk, seven as moderate risk, and the rest as low risk. In all patients but four, reconstruction was accomplished by using their stomachs as a substitute. In the remaining patient, intestinal continuity was established by a left and right colonic interposition. Three patients were lost in the early postoperative period. Two patients categorized as low risk died from pulmonary thromboembolism and cardiac failure, respectively. One patient categorized in the high risk group died of coronary thrombosis. Postoperative complications included transient hoarseness due to recurrent laryngeal nerve paresis in one patient, right pleural effusion in one patient, pneumothorax in two patients, and thrombophlebitis in one patient. In the high risk patient group, there were no pulmonary complications. This clinical study demonstrated the protective effect of THE in patients with serious pulmonary problems.
American Journal of Surgery, Feb 1, 2004
Turkish Journal of Trauma and Emergency Surgery
Turkish Journal of Colorectal Disease
Turkish Journal of Medical Sciences, 1996
Konuralp Tıp Dergisi, 2021
Objective: To investigate the emergency department admissions, the general surgery consultation r... more Objective: To investigate the emergency department admissions, the general surgery consultation request, and the necessity of immediate treatment of patients despite the fact that the society did not leave the house unless necessary during the pandemic period. Methods: The files of patients who admitted to the emergency department and whose general surgery consultation was requested due to urgent surgical treatment were retrospectively scanned between March-May 2020, which is the Covid 19 pandemic period and March-May 2019, as a time period in which normal social life continues. Age, gender, complaints, comorbid diseases, the necessity of truly emergency surgical treatment as well as the socioeconomic level scale for each individual were recorded and analyzed. Results: The rate of request for consultation was 2.7% (n = 170) in the pandemic period, and 3.1% (n = 316) in the non-pandemic period. In both periods, no statistically significant difference was found in the distribution of ...
Namık Kemal Tıp Dergisi, 2021
Aim: Esophageal cancer is a fatal disease where the majority of patients are diagnosed at an adva... more Aim: Esophageal cancer is a fatal disease where the majority of patients are diagnosed at an advanced stage. In this study, we aimed to present the demographic and clinicopathological characteristics of patients who were operated for esophageal cancer. Materials and Methods: A total of 847 patients who underwent surgery, chemoradiotherapy, or palliative procedures for esophageal pathology between the years of 1985 and 2018 were retrospectively analyzed. Age, gender, tumor location, histopathology, surgical technique, and chemoradiotherapy history of patients were analyzed. Results: In the study, 488 patients were male (60.5%) and 319 were female (39.5%). The ratio of males and females was 1.52. The average age was 58.6 years, and 80.1% were older than 50 years. The most common pathological material obtained was squamous cell carcinoma (67.5%), followed by adenocarcinoma (27.7%). Total esophagectomy was performed in 435 patients; distal esophagectomy was performed in 38 patients. Tra...
Annals of Medical Research, 2021
Anaesthesia, 2021
SummaryPeri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this stu... more SummaryPeri‐operative SARS‐CoV‐2 infection increases postoperative mortality. The aim of this study was to determine the optimal duration of planned delay before surgery in patients who have had SARS‐CoV‐2 infection. This international, multicentre, prospective cohort study included patients undergoing elective or emergency surgery during October 2020. Surgical patients with pre‐operative SARS‐CoV‐2 infection were compared with those without previous SARS‐CoV‐2 infection. The primary outcome measure was 30‐day postoperative mortality. Logistic regression models were used to calculate adjusted 30‐day mortality rates stratified by time from diagnosis of SARS‐CoV‐2 infection to surgery. Among 140,231 patients (116 countries), 3127 patients (2.2%) had a pre‐operative SARS‐CoV‐2 diagnosis. Adjusted 30‐day mortality in patients without SARS‐CoV‐2 infection was 1.5% (95%CI 1.4–1.5). In patients with a pre‐operative SARS‐CoV‐2 diagnosis, mortality was increased in patients having surgery wi...
British Journal of Surgery, 2021
Background This study aimed to determine the impact of pulmonary complications on death after sur... more Background This study aimed to determine the impact of pulmonary complications on death after surgery both before and during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Methods This was a patient-level, comparative analysis of two, international prospective cohort studies: one before the pandemic (January–October 2019) and the second during the SARS-CoV-2 pandemic (local emergence of COVID-19 up to 19 April 2020). Both included patients undergoing elective resection of an intra-abdominal cancer with curative intent across five surgical oncology disciplines. Patient selection and rates of 30-day postoperative pulmonary complications were compared. The primary outcome was 30-day postoperative mortality. Mediation analysis using a natural-effects model was used to estimate the proportion of deaths during the pandemic attributable to SARS-CoV-2 infection. Results This study included 7402 patients from 50 countries; 3031 (40.9 per cent) underwent surgery be...
Anaesthesia, 2021
SummarySARS‐CoV‐2 has been associated with an increased rate of venous thromboembolism in critica... more SummarySARS‐CoV‐2 has been associated with an increased rate of venous thromboembolism in critically ill patients. Since surgical patients are already at higher risk of venous thromboembolism than general populations, this study aimed to determine if patients with peri‐operative or prior SARS‐CoV‐2 were at further increased risk of venous thromboembolism. We conducted a planned sub‐study and analysis from an international, multicentre, prospective cohort study of elective and emergency patients undergoing surgery during October 2020. Patients from all surgical specialties were included. The primary outcome measure was venous thromboembolism (pulmonary embolism or deep vein thrombosis) within 30 days of surgery. SARS‐CoV‐2 diagnosis was defined as peri‐operative (7 days before to 30 days after surgery); recent (1–6 weeks before surgery); previous (≥7 weeks before surgery); or none. Information on prophylaxis regimens or pre‐operative anti‐coagulation for baseline comorbidities was no...
British Journal of Surgery, 2021
To support the global restart of elective surgery, data from an international prospective cohort ... more To support the global restart of elective surgery, data from an international prospective cohort study of 8492 patients (69 countries) was analysed using artificial intelligence (machine learning techniques) to develop a predictive score for mortality in surgical patients with SARS-CoV-2. We found that patient rather than operation factors were the best predictors and used these to create the COVIDsurg Mortality Score (https://covidsurgrisk.app). Our data demonstrates that it is safe to restart a wide range of surgical services for selected patients.
… Klinikleri Journal of …, 1997
... 15:48) Ömer Özkan'dan ... 13:23) Twitter'da canlı canlı açık kalp ... Medical Resea... more ... 15:48) Ömer Özkan'dan ... 13:23) Twitter'da canlı canlı açık kalp ... Medical Research Year: 1997 / Volume: 15 / No: 1. Repair Of Stomach Defects By Dehydrated Dura Mater Patch İn The Rat Salih PEKMEZCİ a , M.Faik ÖZÇELİK a , Ediz ALTINLI a , Süha GÖKSEL b , Murat VARDAR ...
Journal of Hepato-Biliary-Pancreatic Surgery, 2002
Journal of Surgical Research, 2008
Background. The aim of this paper is to assess the effects of halofuginone, a specific inhibitor ... more Background. The aim of this paper is to assess the effects of halofuginone, a specific inhibitor of synthesis of collagen Type 1, on fibrogenetic process in an experimental model of early pancreatic fibrosis. Methods. Thirty rats were divided into three equal groups: group 1, sham laparotomy; group 2, severe hyperstimulation and obstruction pancreatitis (SHOP) with no treatment; group 3, SHOP with halofuginone treatment group. SHOP model was induced by complete pancreatic duct obstruction and daily cerulein hyperstimulation (50 g/kg, intraperitoneally). Halofuginone was administered daily from the operative day (5 mg/kg, intraperitoneally). All of the animals were sacrificed, and blood and pancreatic tissue samples were obtained for biochemical and histopathological examination on the 5th postoperative day. Results. No mortality was observed in any group. Serum amylase, lipase, hyaluronic acid, and nitric oxide levels were significantly higher in groups 2 and 3 compared with group 1 (P < 0.05), but were significantly lower in group 3 compared with group 2 (P < 0.05). No significant differences were observed regarding serum malondialdehyde and glutathione levels between groups 1 and 3. Tissue hydroxyproline levels were found to be significantly higher in groups 2 and 3 compared with group 1 (P < 0.001), but were significantly lower in group 3 compared with group 2 (P < 0.001). Although tissue hydroxyproline levels were significantly higher in the halofuginone treatment group compared with the control group, histopathological evaluation did not reveal a significant difference between these groups regarding collagen deposition. When group 3 was compared with group 2, halofuginone significantly reduced inflammation and acinar atrophy in the pancreas as well (P < 0.05). Conclusion. Halofuginone was found to be effective in reducing SHOP-related inflammation, acinar atrophy, and fibrosis in the pancreas.