Browsing by Author "Ozkan, Burak"

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35-year Onset of a Squamous Cell Carcinoma Originating from Sacral Pilonidal Sinus
(2019) Ozkan, Burak; Cologlu, Harun; Uysal, Cagrı A.; Ertas, Nilgun M.; 32537300
Aesthetic Surgery in Transplant Patients: A Single Center Experience
(2018) Ozkan, Burak; Albayati, Abbas; Eyuboglu, Atilla Adnan; Uysal, Ahmet Cagri; Ertas, Nilgun Markal; Haberal, Mehmet; 0000-0003-3093-8369; 0000-0003-2806-3006; 0000-0002-9805-9830; 0000-0001-6236-0050; 0000-0002-3462-7632; 29528026; AAI-5063-2020; AAC-3344-2021; AIC-3493-2022; AAJ-2949-2021; AAJ-8097-2021
Objectives: Transplant patients, like the nontransplant population, can have surgical interventions for body shape disorders. Studies on aesthetic surgeries in transplant patients are scarce. Our aim was to share our experiences with various aesthetic procedures in solid-organ transplant recipients. Materials and Methods: Six (5 female, 1 male) transplant patients who received surgical corrections of the aging face, ptosis and lipodystrophy of the breast, and abdomen at the Baskent University Plastic Reconstructive and Aesthetic Surgery Department between 2010 and 2017 were included. Five patients had renal transplants, and 1 patient had liver transplant. Minimal aesthetic procedures, including botulinum toxin, dermal filler injections, and scar revisions, were excluded. All patients were consulted to transplant team preoperatively and hospitalized in the transplant inpatient clinic. Results: Mean age was 46 years. Aesthetic surgeries included breast reduction (2 patients), high suprasuperficial musculoaponeurotic system face lift (1 patient), blepharoplasty (2 patients), and dermofat grafting (1 patient). Mean hospitalization duration was 2.5 days. Four patients had no minor or major complications. One patient had skin flap necrosis, which healed with secondary intention. Another patient had ectropion after lower lid blepharoplasty, which was corrected with another procedure. Conclusions: Transplant patients are a special group of patients who receive long-term immunosuppressive treatment and medications like high-dose steroids. These treatments can lead to dermal atrophy and cause pseudo-skin laxity. Removal of excess skin and fat tissue should be considered. Efforts should be made to avoid complications such as skin necrosis and unpredictable wound healing problems when resetting the excess tissue. Preoperative consultation with transplant surgeons and keeping operative times short are other important factors. Body dysmorphologies that interfere with normal life activities and demand for younger appearance are the main reasons of aesthetic procedures. Transplant patients can be operated safely with preoperative planning, consultation with transplant surgeons, and close follow-up.
Augmented Reality-assisted Planning of Midpalmar Space Infection of the Hand
(2021) Ozkan, Burak; Akinci, Kadri; Savran, Suleyman; Uysal, Ahmet Cagri; Ertas, Nilgun Markal
Bilateral Isolated Blowout Fracture Due to Airbag Deployment
(2021) Ozkan, Burak; Akinci, Kadri; Uysal, Cagri Ahmet; Ertas, Nilgun Markal
The airbag is a lifesaver innovation in automobile industry, but the impact of airbag deployment may cause maxillofacial fractures. Airbag deployment in traffic accidents is a rare etiology of orbital fractures. Although there are reports about airbag-induced orbital fractures in the literature, isolated bilateral blowout fractures have not been published yet. We present a case of isolated bilateral blowout fracture due to airbag deployment in a traffic accident and its management in this study.
Bilateral Propeller Flap Closure of Large Meningomyelocele Defects
(2014) Cologlu, Harun; Ozkan, Burak; Uysal, Ahmet Cagri; Cologlu, Ozlem; Borman, Huseyin; https://orcid.org/0000-0002-8605-9032; https://orcid.org/0000-0003-3093-8369; https://orcid.org/0000-0001-6236-0050; 24918736; AAO-4286-2020; AAI-5063-2020; AAJ-2949-2021
Background: Meningomyelocele is a defect of the spinal cord, vertebral spine, and overlying skin and is the most common form of spinal dysraphism. Multiple methods of soft tissue closure for larger myelomeningocele defects have been described, including skin grafting, random fasciocutaneous flaps, skin undermining with relaxing incisions, and musculocutaneous flaps. Most current methods for closure of defects of 8 cm and greater and kyphotic spines usually remains inadequate. In this study, we present our clinical experience with a new surgical procedure, bilateral propeller (BP) flaps based on dorsal intercostal and lumbar artery perforator, for the closure of large thoracolumbar meningomyelocele defects. Patients and Method: Between January 2011 and April 2012, 7 newborns (5 males and 2 females) with thoracolumbar large meningomyelocele were included in the study. Six patients had lumbar kyphosis. Myelomeningocele defects with a mean size of 89.3 cm(2) (range, 58.9-136.8) were closed with BP flaps. Results: All flaps survived; hematoma, seroma, wound dehiscence, flap necrosis, or infection was not observed. No patients required any surgical revisions. The patients had a follow-up of 4 to 16 months with a mean of 10 months, and no long-term complications, including necrosis of flap edges, wound breakdown, or instability, have been apparent in our series. Conclusions: We believe that the BP flaps represent a useful tool in the management of soft tissue defects associated with especially kyphotic large thoracolumbar and lumbosacral myelomeningoceles.
Clinical Experiences with Closed Incisional Negative Pressure Wound Treatment on Various Anatomic Locations
(2020) Ozkan, Burak; Ertas, Nilgun Markal; Bali, Ulas; Uysal, Cagri A.; 0000-0003-3093-8369; 0000-0001-6236-0050; AAI-5063-2020; AAJ-2949-2021
Background Closed incisional negative pressure wound treatment (ciNPWT) is one of the promising methods for the prevention of complications in surgical incisions. The mechanisms of ciNPWT have previously been elucidated and in this series, we demonstrate various, as of yet, underreported uses for the technology. Our aim is to share our experience with ciNPWT on various anatomic sites with novel indications. Materials and methods ciNPWT was used in 24 patients. The mean age was 49.6. All the incisions were sutured, clean, and non-infected. Patients' sex, age, comorbidities, anatomic location of the wound, and the indications for ciNPWT were recorded. Results The mean number of applications was three per patient. One suture dehiscence after one session of ciNPWT was encountered in a flap donor site of an infant operated for meningomyelocele. Late-term seroma and hematoma formation were encountered in two patients. No surgical site infection, wound dehiscence, and ciNPWT related complications were seen in other patients. The majority of the applications were on the trunk, lower extremity, pelvis, upper extremity, and scalp respectively. Indications for ciNPWT utilization were preventing dehiscence, seroma, and hematoma formation in the majority of the patients. Conclusion ciNPWT is reliable and effective in the prevention of post-operative wound dehiscence and surgical site infections. It can be used safely in various locations and different indications for preventing complications such as preventing dehiscence in revision surgeries, cerebrospinal fluid (CSF) fistula formation in the scalp, and wound breakdown in chronic corticosteroid use,
A Custom-Made Nostril Retainer for Adult Population
(2020) Ozkan, Burak; Albayati, Abbas; Akinci, Kadri; Uysal, Cagri A.; Ertas, Nilgun M.; 0000-0001-6236-0050; 32371700
Elongation of the stylohyoid process or calcification of the stylohyoid ligament is known as the Eagle syndrome. Mostly, it is seen incidentally on imaging or with extreme suspicion and usually patients are asymptomatic. Surgery is the preferred method in symptomatic patients. Transcervical or transoral methods may be preferred as surgical route. A 28-year-old female patient who had formerly underwent tonsillectomy presented with throat and ear pain. A neck computed tomography was performed, and the patient was diagnosed as Eagle Syndrome. Surgery was recommended. Patient developed transient velopharyngeal insufficiency on postoperative day 4. Ventilation exercise and follow-up was recommended. Complaints of the patient decreased on the 15th day. It should be kept in mind that stylohyoid ligament may be calcified in young age group and middle age group patients with dysphagia or odynophagia, and differential diagnosis should be performed. Another issue is the condition of velofaringeal insufficiency which may occur due to the damage of the pharynx muscles by deep dissection during surgery.
A descriptive study of facial lacerations presenting to pediatric emergency in Turkey
(2021) Albayati, Abbas; Ozkan, Burak; Eyuboglu, Atilla; Uysal, Cagri A.; Ertas, Nilgun M.; https://orcid.org/0000-0003-2806-3006; https://orcid.org/0000-0001-6236-0050; 33394475; AAC-3344-2021; AAJ-2949-2021
BACKGROUND: Soft tissue trauma of the face is considered a leading cause of presentation and referral to the pediatric emergency department. The present study aims to evaluate the demographics properties of facial injuries presenting to the pediatric emergency. METHODS: In this study, 1160 patients presented with a simple facial laceration to the pediatric emergency department of Baskent University were reviewed from 2011 to 2017. Patients up to 18 years of age were included. We evaluated demographics about patients' age, sex, the cause of injury, the location of laceration and timing of the injury. Age was categorized according to the National Institute of Child Health and Human Development (NICHD) pediatric terminology into five groups as follows: 0-12 months, 12 months-2 years, 2-5 year, 6-11 year, and 12-18 years. The following analyses were performed to each age group: a number of cases, male to female predominance, timing of injury (e.g., early morning, afternoon, evening, late evening and at night), the place that the injury has occurred (e.g., at home, at school, in sport hall), the cause of injury (fall, hitting a hard subject, sports-related), the location of laceration (forehead, periorbital area, cheek, perioral area, nose, submental area) and the incidence according to the season. RESULTS: Number and relative percentages of cases were as follows: 0-12 months (n=127, 10.9%), 12-24 months (n=113, 9.7%), 3-5 years (n=385, 33.1%), 6-11 years (n=403, 34.7%) and 12-17 years (n=132, 11.3%). The average age of children was 6.5 year (range, 5 month - 17.9 year). The age group 6-11 showed a higher incidence compared to other age groups (n=403, 34.7%). Fifty-three percent of the population was younger than six years and there was a male predominance in all age groups. CONCLUSION: The demographic data provided in this study can be useful in trauma prevention programs which are effective in reducing the incidence, nature and severity of facial lacerations. Parents should be reminded of age-specific preventive measures in injury avoidance.
Does methylene blue increases capsular contracture in immediate breast reconstruction with silicone implant? An experimental study
(2020) Albayati, Abbas; Ozkan, Burak; Atilgan, Alev O.; Sencelikel, Tugce; Uysal, Cagri A.; Ertas, Nilgun M.; 0000-0003-2806-3006; 0000-0001-8595-8880; 0000-0001-6236-0050; 0000-0003-3093-8369; 33030384; AAC-3344-2021; AAK-3333-2021; AAJ-2949-2021
Recently, most of the immediate breast reconstructions following mastectomy are being carried out with the use of silicone implants. In these patients, methylene blue is being used for the detection of sentinel lymph nodes. This experimental study was performed to determine the effect of methylene blue on capsular contracture around breast implants. Thirty-two Sprague Dawley rats were divided into 4 groups. Custom made silicone blocks were placed on the back of animals. In group 1, the incision was closed without performing any additional procedure. In group 2 (control), 0.1 mL of 0.9% normal saline was instilled into the pocket. Group 3 and 4 (study groups) received 0.1 and 0.2 mL of 1% methylene blue, respectively. On postoperative day 60, implants and capsular tissue were extracted. Capsule formation was evaluated both macroscopically and microscopically. The histological evaluation included capsule thickness, inflammation, neovascularization, and fibrosis gradients. Regarding capsule thickness, there were statistically significant differences between groups 1-3, 1-4, 2-3, and 2-4. Although there were more moderate and severe inflammation gradients in groups III and IV, there was no significant difference regarding inflammation severity between control and study groups. In respect of vascular proliferation, there was a statistically significant difference between control and study groups. Similarly, fibrosis gradients were higher in both groups 3 and 4. The study showed that the injection of methylene blue around silicone implants enhanced the formation of capsular contracture. In this case, the degree of contracture was independent of the dose given.
Double Layer Reconstruction of Exposed Cardiac Implantable Electronic Devices in Elderly Patients
(2021) Ozkan, Burak; Albayati, Abbas; Yilmaz, Kerem C.; Ciftci, Orcun; Ozin, Bulent; Uysal, Cagri A.; Ertas, Nilgun Markal; 0000-0001-8926-9142; 33542888; AAJ-1331-2021; W-5233-2018
Background Elderly patients with multiple comorbidities may not be candidates for cardiac implanted electronic device (CIED) explantation in cases of exposition. Excision of all unhealthy and inflamed scar tissue results in a skin defect that must be covered. Small- to moderate-sized local skin flaps and subpectoral placement of CIEDs have been described in the literature. However, these techniques still could not eliminate the risk of recurrence. In terms of minimizing the recurrence risk, we aim to increase the flap dimensions for getting better circulation and tension-free closure after subpectoral placement. Material and methods Six patients who were operated for a dual-layer reconstruction of exposed cardiac implants between 2017 and 2020 were included in the study. All patients were referred to plastic surgery as soon as the wound biopsy culture results were negative after systemic and topical antibiotic treatment by cardiology department. Results No flap loss or wound dehiscence was seen with a mean duration of 11 months follow-up. Early hematoma was encountered in a patient who was managed with irrigation and drain renewal. One patient developed suture abscess in the second month postoperatively. Knots were removed and wound healed without further intervention. Conclusion Double layer closure of exposed cardiac implants with large breast fasciocutaneous flap after subpectoral placement of pulse generator and leads suggest durable and reliable coverage in elderly patients with multiple comorbidities.
The Effect of Adipose Derived Stromal Vascular Fraction on Flap Viability in Experimental Diabetes Mellitus and Chronic Renal Disease
(2022) Ozkan, Burak; Eyuboglu, Atilla Adnan; Terzi, Aysen; Ozturan Ozer, Eda; Tatar, Burak Ergun; Uysal, Cagri A.; 0000-0003-3093-8369; 35450516
Background The presence of chronic renal disease(CRD) concurrently with diabetes mellitus(DM) increases the flap failure. Adipose derived stromal vascular fraction (SVF) is known to enhance skin flap viability in both healthy and diabetic individuals. The aim of this experimental study was to investigate the effect of SVF on skin flap viability in rats with DM and CRD. Methods 48 Sprague-Dawley rats were separated into four groups as follows: group I (control), group II (diabetes mellitus), group III (chronic renal disease), and group IV (diabetes with chronic renal disease).Two dorsal flaps were elevated. Flaps on left side of all groups received 0.5 cc of SVF, while same amount of plasma-buffered saline (PBS) was injected into right side. On postoperative day 7, flaps were harvested for macroscopic, histopathologic and biochemical assessments. Areas of flap survival were measured macroscopically. Blood level of vascular endothelial growth factor (VEGF) was measured after injection of SVF. Results Macroscopically, SVF has significantly improved flap viability (p < 0.05). Flap viability percentage was lower in DM and CRD groups when compared with healthy control group. In respect of new capillary formation, there was a statistically significant difference between SVF injected flaps and PBS injected sides (p < 0.05). Similarly, VEGF levels were higher in all study groups and there was a significant difference in comparison to control group (p < 0.05). Conclusions The study showed that injection of SVF increased flap viability via endothelial differentiation and neovascularization. In vivo function of stem cells might be impaired due to uremia and diabetes-related microenviromental changes.
The Effect of Adipose Stromal Vascular Fraction on the Viability of Transverse Rectus Abdominis Myocutaneous Flap after Abdominoplasty: An Experimental Study
(2021) Coskun, Erhan; Ozkan, Burak; Terzi, Aysen; Ozer, Eda Ozturan; Uysal, Cagri Ahmet; Borman, Huseyin; Ertas, Nilgun Markal; 0000-0002-1225-1320; F-7546-2013
Introduction: A prior abdominoplasty is considered as an absolute contraindication to transverse rectus abdominis musculocutaneous (TRAM) flap surgery. The aim of this study is to investigate the effect of nonexpanded adipose stromal vascular fraction (ASVF) on the viability of TRAM flap after abdominoplasty. Materials and Methods: Thirty-five male Sprague Dawley rats were divided into five groups. Reverse abdominoplasty model was used in all groups except Group 1. TRAM flap was performed 2 weeks after abdominoplasty in Groups 2 and 4 and 4 weeks after in Groups 3 and 5. ASVF cells were injected during abdominoplasty in Groups 4 and 5. The viable flap area (VFA) percentage and newly formed perforators were assessed. Capillary density and fibrosis gradient and plasma vascular endothelial growth factor (VEGF) levels were measured. Results: The mean VFA to total flap area was measured as 82.90% +/- 7.59%, 3.31% +/- 3.29%, 9.40% +/- 6.18%, 31.92% +/- 9.29%, and 64.98% +/- 10.95% in Group 1, Group 2, Group 3, Group 4, and Group 5, respectively (P < 0.05). The number of newly formed musculocutaneous perforating arteries was 0.29 +/- 0.49, 1.14 +/- 0.69, and 2 +/- 0.82 for Groups 3, 4, and 5, respectively (P < 0.05). The mean capillary density was 6.86 +/- 0.50, 0.67 +/- 0.13, 2.79 +/- 0.53, 3.71 +/- 0.47, and 7.01 +/- 0.70 in Groups 1, 2, 3, 4, and 5, respectively (P < 0.05). There was a statistically significant increase between the baseline VEGF values and the second VEGF values in Groups 4 and 5. Conclusions: The study showed that local injection of ASVF increases the viability of TRAM flap after abdominoplasty.
Effect of long-term intermittent hypothermia on random skin flap viability and new vessel formation
(2020) Caglar, Ibrahim Baris; Ozkan, Burak; Albayati, Abbas; Uysal, Ahmet Cagri; Ertas, Nilgun Markal; 0000-0001-6236-0050; 0000-0003-2806-3006; AAJ-2949-2021; AAC-3344-2021
Background: Preconditioning is the improving the overall viability of the flaps before surgery. Hypothermia is one of preconditioning methods. In literature, the effect of short time hypothermia in skin flap viability has been studied. However, there is no information about the effects of long-term application of hypothermia on skin flap viability. In this study, we investigated the effect of long-term local hypothermia on flap viability and new vessel formation on random pattern skin flaps. Materials and Methods: Thirty-six adult male Sprague-Dawley rats were used. The flap model was, 3 cm x 9 cm sized random pattern skin flap. Three groups were composed as control group, continuous hypothermia induction group with ice bags, and intermittent hypothermia induction with chloroethyl spray. Flaps were raised on the 15th day of hypothermia sessions. Flap viability was measured in the software program. Microangiography and blood vascular endothelial growth factor (VEGF) levels were assessed for the detection of new vessel formation. Results: Average flap viabilities were found to be 64.87% in Group I, 57.69% in Group II, and 62.22% in Group III. The difference between Group II and other groups were statistically significant. When microangiographies were examined macroscopically, diameters, and amount of vascular branches of vessels in Group II were found to be higher than other groups. The difference between blood VEGF levels day 1 values among groups was not statistically significant. When day 4 values were compared to baseline values difference in Group III was statistically significant. At days 7 and 15, differences between groups and corresponding baseline values were not statistically significant. Conclusion: Continuous long-term application of hypothermia with ice-water bags causes a significant increase in neovascularization in random pattern skin flaps without an increase in skin flap viability. Hence, we can say that 2 weeks of hypothermia on random pattern skin flaps is not an efficient preconditioning method in clinical use.
The Effects of Adipose Derived Stromal Vascular Fraction and Platelet-Rich Plasma on Bone Healing of a Rat Model With Chronic Kidney Disease
(2020) Eyuboglu, Atilla Adnan; Arpaci, Enver; Albayati, Abbas; Uysal, Ahmet Cagri; Terzi, Aysen; Bozalioglu, Sema; Turnaoglu, Hale; Balcik, Cenk; Ozkan, Burak; Ertas, Nilgun Markal; 0000-0002-0781-0036; 0000-0003-2806-3006; 0000-0001-6236-0050; 32784349; AAK-8242-2021; AAC-3344-2021; AAJ-2949-2021
Background Chronic kidney disease (CKD) impairs osteoblast/osteoclast balance and damages bone structure with diminished mineralization and results in bone restoration disorders. In this study, we investigate the effects of adipose-derived stromal vascular fraction and platelet-rich plasma (PRP) on bone healing model in rats with CKD. Methods Sprague-Dawley rats were separated into 4 groups. All groups except group I (healthy control) had CKD surgery using 5/6 nephrectomy model. All groups had intramedullary pin fixation after receiving bone fracture using drilling tools. Group II rats were used as control group for CKD. Group III rats received PRP treatment on fracture site. Group IV rats received PRP and stromal vascular fraction treatment on fracture site. Weight loss and blood samples were followed at the time of kidney surgery, third, sixth, and 12th weeks. Bone healing and callus formations were compared, biomechanically, radiologically, histopathologically, and immunohistochemically. Osteoblastic transformation of stem cells was assessed with DiI staining. Results Negative effects of CKD on bone healing were reduced by increasing mechanical, histological, radiological, and biochemical properties of the bone with stromal vascular fraction and PRP treatments. Although thickness of callus tissue delayed bone healing process, it also enhanced biomechanical features and bone tissue organization. Conclusions Platelet-rich plasma and adipose-derived stromal vascular fraction treatments were effective for bone healing in animal model, which can be promising for clinical trials.
Escharotomy for the Face: Facial Aesthetic Subunit Principle-Based Approach
(2021) Ozkan, Burak; Ertas, Nilgun M; Uysal, Cagri A.; Haberal, Mehmet; 0000-0002-3462-7632; 0000-0003-3093-8369; 32845003; AAJ-8097-2021
Escharotomy is the relaxation of an eschar through longitudinal or horizontal incisions in order to protect regional perfusion. In peripheral areas, such as limbs, trunk, and neck, eschar pressure poses significant issues; it causes circulatory disorder in limbs and potential limb loss, inadequate thoracic expansion in the thorax, and perfusion and oxygenation problems in the neck. To prevent complications, a basic rule of burn surgery is to perform escharotomy incisions quickly and without hesitation. However, the face is not an area in which eschar formation is commonly seen due to its robust vascular supply and patients' protection reflex. Although descriptive drawings and guides for facial escharotomy have yet to be published, relaxation of axial arteries in terms of compression from eschar formation may be needed. Here, we present a case of escharotomy based on facial subunit principles.
Extraocular Sebaceous Carcinoma in Muir-Torre Syndrome
(2022) Albayati, Abbas; Ozkan, Burak; Ayva, Ebru Sebnem; Uysal, Ahmet Cagri; Ertas, Nilgun Markal; 0000-0003-2806-3006; 36092191; AAC-3344-2021
Giant Basal Cell Carcinoma Causing Axillary Contracture: A Case Report of an Unusual Localization of an Advanced Case
(2023) Albayati, Abbas; Ozkan, Burak; Tepeoglu, Merih; Uysal, Cagri A.; 0000-0003-2806-3006; 0000-0003-3093-8369; 0000-0001-6236-0050; 38061706; AAC-3344-2021
Basal cell carcinoma (BCC) is the most common type of non-melanoma skin cancer. Although BCC arises most commonly in sun-exposed areas of the body, such as the head and neck, it infrequently can be seen in sun-protected parts as well. Axilla is one of the least encountered areas of BCC. Delay in the diagnosis or management alongside negligence of the patient can lead to a tumor reaching a giant size. We report a case of giant axillary BCC in a 59-years old female patient with no known risk factors for skin cancers. The tumor was excised with wide margins, and the tissue defect was reconstructed with latissimus dorsi musculocutaneous flap. A 3-year follow-up did not show any sign of recurrence or metastasis.
Inferior Gluteal Artery Perforator Flap for Closure of Sacral Defects after Pilonidal Sinus Surgery
(2019) Bali, Zulfikar Ulas; Ahmedov, Anvar; Ozkan, Burak; Mazican, Mustafa; Kececi, Yavuz; 0000-0003-3093-8369; AAI-5063-2020
Introduction: The aim of the current study was to introduce the use of the inferior gluteal artery perforator flap (IGAPF) as a new alternative surgical technique for closure of sacral defects after pilonidal sinus surgery. Patients and Methods: Inferior gluteal artery perforators were used on 15 male patients operated in the plastic and reconstructive surgery deportment of our tertiary care centers between March 2014 and May 2017. Age, size of the defect, duration of follow-up, complications, and recurrence rate were assessed. Results: The average age was 30.2 (range: 17-54) years, and the mean duration of follow-up was 8.2 (range: 7-16) months. No recurrence was detected within the follow-up period, and the only remarkable complication reported was total flap necrosis attributed to venous congestion in one patient. The mean size of the defects after excision was 21.6 cm(2). Conclusion: Our preliminary results imply that IGAPF can be a safe and effective alternative for closure of large defects after pilonidal sinus surgery. Further controlled trials on larger series are warranted to establish the advantages and disadvantages of this alternative technique.
Inhibition of the Notch Pathway Promotes Flap Survival by Inducing Functional Neoangiogenesis
(2015) Abbas, Ozan Luay; Borman, Huseyin; Terzi, Yunus K.; Terzi, Aysen; Bayraktar, Nilufer; Ozkan, Burak; Yazici, Ayse C.; 0000-0002-7886-3688; 0000-0003-3093-8369; 0000-0002-1225-1320; 0000-0002-3132-242X; 0000-0001-5612-9696; 25180956; Y-8758-2018; AAI-5063-2020; F-7546-2013; AAS-6810-2021; B-4372-2018
Objective The Notch pathway seems to function as an antiangiogenic factor, negatively regulating the sprouting effect of vascular endothelial growth factor (VEGF). This function is well defined in embryonic and tumor vasculature. However, little is known about its function in ischemia-induced angiogenesis. In the first part of this study, we investigated the role of Notch in reparative angiogenesis after ischemia. In the second part, we hypothesized that anti-Notch therapy will result in increased angiogenic sprouting. We analyzed the effect of Notch inhibition in the induction of angiogenic sprouting. Methods In the first part, we investigated the effect of ischemia on the Notch ligand delta-like ligand 4 (DLL4). Twenty rats were divided equally into 2 groups. In the surgery group, dorsal skin flap was used as model of ischemia. In the control group, no surgical procedure was performed. DLL4 and VEGF gene expressions were assessed. Immunohistochemical staining was used for detection of DLL4 in tissue materials. Plasma levels of VEGF and DLL4 were measured. In the second part, we investigated the effect of Notch inhibition using a gamma-secretase inhibitor (GSI) on inducing neoangiogenesis. Twenty rats were assigned to 2 equal groups. In all animals, dorsal skin flap was raised and sutured back into its bed. Animals in the GSI-treated group received GSI intravenously after surgery for 3 days. Saline was administered in the control group. Necrotic area measurements, microangiography, and histologic evaluations were performed to compare groups. Results In the first part, VEGF and DLL expressions increased in ischemic tissues (P < 0.01). Immunohistochemical analysis revealed that DLL4 expression was upregulated in capillary endothelial cells after ischemia. Plasma levels for VEGF and DLL4 were higher in the animals that underwent surgery (P < 0.01). In the second part, GSI treatment resulted in higher flap survival rates (P < 0.05). Microscopic analysis exhibited increase in the number of microvascular structures after GSI treatment (P < 0.05). Microangiographic evaluation showed that neovascularization increased in the GSI-applied flaps. Conclusions We present an evidence for the importance of the Notch pathway in the regulation of ischemia-induced angiogenesis. Notch inhibition promotes flap survival by creating a neovasculature that has an increase in vascular density.
Non Melanoma Skin Cancers in Solid Organ Transplant Recipients: A Single Center Experience
(2018) Ertas, Nilgun Markal; Uysal, A. Cagri; Albayati, Abbas; Ozkan, Burak; Haberal, Mehmet; 0000-0003-2806-3006; 0000-0003-3093-8369; 0000-0002-3462-7632; AAC-3344-2021; AAI-5063-2020; AAJ-8097-2021