Browsing by Author "Abbas, Ozan Luay"

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Anthropometric Measurement and Analysis of the Lower Face in Turkish Rhinoplasty Patients
(2015) Abbas, Ozan Luay; Kurkcoglu, Ayla; Pelin, Can; Yazici, Ayse Canan; 0000-0003-0901-8883; 0000-0002-3132-242X; AEJ-3035-2022; AAS-6810-2021
Background Lower face dimensions have a great impact on the perception of nasal beauty. For this reason, evaluation of the lower face is important in patients applied for rhinoplasty. In this study, we aimed to describe the values of lower face anthropometric measurements in Turkish patients who applied for rhinoplasty and to compare these values with measurements of individuals who are pleased with their nasal appearance. Methods A Turkish population of 252 rhinoplasty-negative individuals and 171 rhinoplasty patients were included in this study as the control and rhinoplasty groups. Using the preoperative photographs of the facial profile, seven vertical measurements were taken and seven indices were used to determine the relationships between measurements of the lower face. Results In the rhinoplasty group, most vertical profile measurements were greater in males. The only variables with no gender differences were lower and upper vermilion heights. Only variables with a significant difference between two groups were upper lip vermilion height in females and upper lip height in males. Conclusions This study provides objective reference material for the evaluation of the lower face when planning for rhinoplasty. Besides, the differences found between two groups emphasize the importance of the nasolabial region when planning for rhinoplasty.
Enhancement of Vascular Endothelial Growth Factor's Angiogenic Capacity by the Therapeutic Modulation of Notch Signalling Improves Tram Flap Survival in Rats Submitted to Nicotine
(2017) Abbas, Ozan Luay; Terzi, Yunus Kasim; Ozatik, Orhan; Ozatik, Fikriye Yasemin; Turna, Gamze; Nar, Rukiye; Musmul, Ahmet; 0000-0001-5612-9696; 0000-0002-4662-6493; 0000-0002-8422-2975; 28277073; B-4372-2018; GXA-2381-2022; HOH-8201-2023
Background: Smoke of cigarettes, and specifically nicotine, has been shown to diminish pedicled transverse rectus abdominis musculocutaneous (TRAM) flap survival. Considering that Notch signalling through its ligand Delta-like 4 (Dll4) functions as anti-angiogenic factor by inhibiting the pro-angiogenic effects of vascular endothelial growth factor (VEGF), it is hypothesised that inhibition of the Notch would promote angiogenesis and increase TRAM flap survival in rats submitted to nicotine. Methods: Twenty rats were treated with nicotine for 28 days preoperatively. Thereafter, a pedicled TRAM flap was created in all animals. The Notch inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine-t-butyl-ester was administered in animals of the treatment group. Animals in the control group were given the same amount of solvent. Five days after the surgery, viable flap areas were determined. Skin samples were evaluated for VEGF and Dll4 mRNA levels. Immunohistochemical analysis was used for the assessment of endothelial Dll4 expression. Vascular density was determined histologically. Plasma levels of VEGF and Dll4 were measured. Results: A significant improvement in TRAM flap surviving area was observed in the treatment group (53.5014.25%) compared with the controls (32.20 +/- 9.15%). Immunohistochemical analysis revealed a significant increase in the number of Dll4 stained vessels in animals of the treatment group (9.2 +/- 1.6) in comparison with the controls (5.7 +/- 1.9). VEGF mRNA levels (0.22 +/- 0.08) in the treatment group were significantly lower than those in the control group (0.36 +/- 0.09). Conclusion: Notch inhibition significantly improved TRAM flap survival in animals exposed to nicotine by promoting VEGF-induced angiogenesis.
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.
The Notch Signaling System Is Involved in the Regulation of Reparative Angiogenesis in the Zone of Stasis
(2017) Abbas, Ozan Luay; Ozatik, Orhan; Terzi, Yunus Kasim; Ozatik, Fikriye Yasemin; Nar, Rukiye; Turna, Gamze; https://orcid.org/0000-0001-5612-9696; 28319529; B-4372-2018
The Notch pathway ligand Delta-like 4 (Dll4) functions as an antiangiogenic factor, inhibiting vascular endothelial growth factor (VEGF)-induced angiogenesis. This function is documented in tumor and embryonic vasculature. However, its implication in burn wounds remains unexplored. Our objective was to explore the involvement of the Notch in the healing of zone of stasis burns. We hypothesized that anti-Dll4 therapy would prevent progressive necrosis in the stasis zone by promoting angiogenesis. Burns were created in 21 rats using the comb burn model. The Notch inhibitor N-[N-(3,5-difluorophenacetyl)1- alanyl]-S-phenylglycine-t-butyl-ester was administered in the treatment group. Controls were given the same amount of solvent. Seven days after the burn, skin samples were evaluated for VEGF and Dll4 gene expressions. Immunohistochemical analysis was used for the assessment of vascular density, endothelial Dll4 expression, and apoptosis count. Histologic grading of tissue damage was performed. Circulating levels of VEGF and Dll4 were determined. VEGF and Dll4 mRNA levels were found to be simultaneously induced after the burn. In the treatment group, a significant increase in the number of vessels was observed. However, gross evaluation documented an expansion of necrosis to the zone of stasis with marked activation of apoptosis. Histologic assessment showed that the resultant vascular overgrowth was accompanied by extensive edema and abundant infiltration of leukocytes. We provide evidence for the involvement of Notch in the regulation of angiogenesis in zone of stasis burns.
Perception of Symmetry in Aesthetic Rhinoplasty Patients: Anthropometric, Demographic, and Psychological Analysis
(2017) Abbas, Ozan Luay; Kurkcuoglu, Ayla; Aytop, Cigdem Derya; Uysal, Cengiz; Pelin, Can; https://orcid.org/0000-0003-0901-8883; 28614976; AEJ-3035-2022
Visual perception of symmetry is a major determinant of satisfaction after aesthetic rhinoplasty. In this study, we sought to investigate the existence of any relationship between anthropometric characteristics of the face and visual perceptions of asymmetry among rhinoplasty patients and to evaluate tools that can shed light on patients who appear at high risk for exaggerating potential asymmetries. In the first part, 168 rhinoplasty patients were asked to fill out the demographic questionnaire, nasal shape evaluation scale, and the somatosensory amplification scale. In the second part, we examined the relationship between anthropometric characteristics of the face and visual perceptions of asymmetry using standardized photographs of 100 medical students. In the third part, patients answered the rhinoplasty outcome evaluation questionnaire 6 months after the surgery. Objectively, no symmetrical face was observed in the anthropometric evaluation. Subjectively, only 73% and 54% of the faces were considered asymmetrical by the rhinoplasty and the control groups, respectively. The rate of asymmetry perception was significantly greater in revision patients when compared with primary rhinoplasty patients. The relationship between the rate of subjective perception of asymmetry and the somatosensory amplification scale scores was statistically significant. We found a significant inverse relationship between the rate of asymmetry perception and the rhinoplasty outcome evaluation scores. Plastic surgeons should be aware of this high selectivity in asymmetry perception, which is associated with poor postoperative satisfaction. Somatosensory amplification scale may help identify rhinoplasty patients at a high risk for exaggerating potential asymmetries.