Cigdem Elmas | Gazi University (original) (raw)

Papers by Cigdem Elmas

Research paper thumbnail of Effects of chitosan and platelet-rich plasma on facial nerve regeneration in an animal model

European Archives of Oto-Rhino-Laryngology, 2021

Purpose There is still no widely-accepted local agent proven to be effective in nerve regeneratio... more Purpose There is still no widely-accepted local agent proven to be effective in nerve regeneration. We aimed to investigate the effects of chitosan gel and platelet-rich plasma Materials and methods Electrophysiological measurements were performed before and immediately after injury. The injured nerves were covered with spongostan impregnated with the following agents: Group 1 (Control Group): Saline at a dose of 50 µl; Group 2: Chitosan (CHT) at a dose of 50 µl; Group 3: PRP at a dose of 50 ml; and Group 4: a solution of CHT with PRP (1:1). The final measurements were performed after 3 weeks and the injured nerve of each rat was removed. Results There were statistically-significant differences between the groups regarding the measurements of the after-treatment values of stimulus threshold (p < 0.05). The best improvement in electrophysiological measurement and histopathological evaluation was found in Group 4 (CHT-PRP). Conclusion Chitosan gel has a positive effect on nerve healing and applying it along with PRP can enhance the effect of chitosan.

Research paper thumbnail of Is there any link between oxidative stress and lung involvement due to inflammatory bowel disease: an experimental study

Hepato-gastroenterology

Lung involvement due to inflammatory bowel disease (IBD) is frequent, however the pathogenic mech... more Lung involvement due to inflammatory bowel disease (IBD) is frequent, however the pathogenic mechanism is still debatable. Although the evidence of inflammation in colonic and lung tissue has been documented, the possible effect of oxidative stress in lung tissue has not been evaluated to date. We sought to assess the effects of oxidant/antioxidants on lung tissue in a model of experimental colitis. Colitis was induced with intra-colonic administration of 4% acetic acid. Control group received isotonic saline. Serum and lung tissue markers of oxidative stress were explored. Serum total oxidant status was significantly higher in the colitis group than the controls while total antioxidant status was similar. The determinants of oxidants including lipid peroxidation assay and myeloperoxidase activity were significantly higher in the lung tissue of the colitis group whereas the indicators of antioxidant capacity determined as superoxide dismutase, catalase, glutathione and glutathione p...

Research paper thumbnail of Ultrastructural Damage in Vascular Endothelium in Rats Treated with Paclitaxel and Doxorubicin

Ultrastructural Pathology, 2006

Endothelium is the first physiological barrier between blood and tissues and can be injured by ph... more Endothelium is the first physiological barrier between blood and tissues and can be injured by physical or chemical stress, particularly by the drugs used in the cancer therapy. Paclitaxel and doxorubicin are frequently used anticancer drugs and their cardiac side effects are well observed in clinical setting. Their side effects on the endothelium are still not clear enough. There are few investigations assessing the damages elicited by the combination use of chemotherapy agents in animal experimental models. The purpose of this study was to examine and compare the side effects of doxorubicin and paclitaxel on endothelium in vivo. The drugs were administered weekly to rats via intraperitoneal injections singly or in combinations. Lastly, aorta endothelium was examined. The most familiar parts of the aorta endothelium are the nucleus, free ribosomes, Weibel-Palada granules, plasmalemmal vesicles, and clear basement membrane. Examination of the endothelium and the related structures revealed some clear degenerative findings. Notably, administration of a paclitaxel and doxorubicin combinations caused the most dramatic change in ultrastructure, which may disrupt many functions of the endothelium.

Research paper thumbnail of 253 Caspase 3 Activity in HCG Treated Descended and Undescended Rat Testes

The Journal of Urology, 2011

Research paper thumbnail of Motor Neurotization by Segmental Epineurectomy and Implantation: Lateral Muscular Neurotization

Journal of Reconstructive Microsurgery, 2008

In this study, we aimed to develop a new muscular neurotization technique, in which transection o... more In this study, we aimed to develop a new muscular neurotization technique, in which transection of the donor nerve is avoided. We investigated the outcome of insertion of the donor nerve within the denervated muscle following segmentary epineurectomy (lateral muscular neurotization). Thirty-five male Wistar rats were evaluated in five groups, including sham control, denervation control, denervation combined with segmentary epineurectomy, direct muscular neurotization, and lateral muscular neurotization. Electromyography, muscle weight measurements, and histological evaluations were performed at postoperative months 2 and 3. The denervation group was statistically successful for denervation as compared with the sham control group for all parameters. The lateral neurotization group was successful in preventing muscle atrophy and gaining reinnervation in electromyographic, histological, and weight parameters. The direct neurotization group was also successful in histological and weight parameters. Lateral muscular neurotization is promising because it does not interrupt the fascicular integrity and is successful in reinnervation; therefore, it seems to be a good alternative for direct muscular neurotization.

Research paper thumbnail of The effect of surgical and chemical denervation on ischaemia/reperfusion injury of skeletal muscle

Journal of Plastic, Reconstructive & Aesthetic Surgery, 2012

Research paper thumbnail of Effect of Platelet-Rich Plasma and Fibrin Glue on Healing of Critical-Size Calvarial Bone Defects

Journal of Craniofacial Surgery, 2009

Despite the insufficient number of experimental studies, platelet-rich plasma (PRP) including hig... more Despite the insufficient number of experimental studies, platelet-rich plasma (PRP) including high amounts of growth factors is introduced to clinical use rapidly. The aim of this study was to compare the effects of PRP and platelet-poor plasma (PPP) on healing of critical-size bone defects.Bilateral full-thickness, critical-size bone defects were created in the parietal bones of 32 rabbits, which had been studied in 4 groups. Saline, thrombin solution, PPP, and PRP were applied to the created defects before closure. Radiologic defect area measurement results at 0, 4, and 16 weeks were compared between the groups. In addition, densities of the newly formed bones at 16th week were studied. Histologic parameters (primary and secondary bone trabecula, neovascularization, and bone marrow and connective tissue formation) were compared between 4- and 16-week groups.More rapid decrease in defect size was observed in groups 3 and 4 than in groups 1 and 2, both in the 4th and 16th weeks. Newly formed bone densities were also found to be higher in these 2 groups. New bone formation was detected to be more rapid considering histologic parameters, in groups 3 and 4 at 4th and 16th weeks.Study demonstrates that PRP and PPP might have favorable effects on bone healing. Although we cannot reveal any statistical difference between these 2 substances considering osteoinductive potential, PRP group has demonstrated superior results compared with fibrin glue group. Higher platelet concentrations may expose beneficial effects of PRP.

Research paper thumbnail of What Wrapped Perichondrial and Periosteal Grafts Offer as Regenerators of New Tissue

Journal of Craniofacial Surgery, 2006

The major goals in contour restoration procedures are to re-establish the desired contour with th... more The major goals in contour restoration procedures are to re-establish the desired contour with the use of resilient and durable materials that can be easily found and harvested. Cartilage grafts are commonly used for these purposes though they often possess a problem of donor site morbidity and shortage of quantity. The neo-cartilage formation capacities of both perichondrium and periosteum are well-known. We aimed to optimize both the amount and quality of the newly forming tissue from perichondrial and periosteal grafts. For this purpose the grafts were wrapped on themselves. Placement of oxidized regenerated cellulose (ORC) within graft layers was performed in two groups with the aim of giving support to the regenerating tissue, and increasing the connective tissue formation within the graft layers. Three-month-old New Zealand white rabbits were used. Group 1 ear perichondrial, and Group 2 calvarium periosteal grafts of 1.4 x 2.4 cm were harvested, folded on themselves, and sutured at the edges to create closed pockets. 0.8 x 0.8 cm sized ORC sheets were placed inside the pockets before wrapping in Group 3 perichondrial and Group 4 periosteal grafts. 0.2-mL autogenous blood was injected in each pocket. All grafts were transplanted under the abdominal muscle fascia, and harvested after 6 weeks. Volumes and weights of wrapped perichondrial grafts were higher than their periosteal counterparts either with or without the inclusion of ORC. Grafts with ORC (Groups 3 and 4) were heavier than the grafts lacking ORC (Groups 1 and 2), in a statistically significant manner (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/= 0.01). Histologically, the inclusion of ORC in both perichondrial and periosteal grafts resulted in an increased amount of fibrosis, yet did not preclude neo-cartilage formation.

Research paper thumbnail of Could nephrotoxicity due to colistin be ameliorated with the use of N-acetylcysteine?

Intensive Care Medicine, 2011

Research paper thumbnail of An ultrastructural investigation in stomach epithelial cells of mice during pregnancy and early lactation

Acta gastro-enterologica Belgica

In this study, stomach epithelial cells from adult nonpregnant, pregnant lactating mice were exam... more In this study, stomach epithelial cells from adult nonpregnant, pregnant lactating mice were examined by histochemical, immunohistochemical and ultrastructural methods. Tissue samples taken from different groups were stained with haematoxylin-eosin and PAS-alcian blue and semithin sections were stained with toluidin blue for light microscopic examination. For ultrastructural examination ultrathin sections were stained with uranyl acetate and lead citrate. Additionally, by applying immunoperoxidase method, the distribution of EGF receptors of all groups was studied. We concluded that in the pregnant mice, stomach surface had lower mucus than the nonpregnant group. The acid content was balanced in active and inactive parietal cells. Examination results of lactating mice were similar to the results obtained from nonpregnant and pregnant mice.

Research paper thumbnail of Effect of platelet-rich plasma on peripheral nerve regeneration

Journal of Reconstructive Microsurgery

Activated platelets release various growth factors, some of which are recognized to improve nerve... more Activated platelets release various growth factors, some of which are recognized to improve nerve regeneration. This study evaluated the effect of platelet-rich plasma (PRP) in end-to-end neurorrhaphy. A total of 45 Wistar rats were used, with the initial five used for PRP preparation. The right hind limbs were used as experimental, with the left as control. The animals were treated in five groups. Group A (n = 4): The right sciatic nerve was dissected only from the sciatic notch to the bifurcation. In all other groups, the nerve was sharply transected and repaired with: group B (n = 8): two sutures; group C (n = 8): six sutures; group D (n = 10): two sutures and PRP; and group E (n = 10): six sutures and PRP. Groups D and E were compared with groups B and C, respectively. Group E had a shorter latency time in electromyography ( P < 0.01) and a thicker myelin layer in the histological evaluation ( P < 0.003) in comparison with group C. These positive effects of PRP were not de...

Research paper thumbnail of Transmission and scanning electron microscopy confirm that bone microstructure is similar in osteopenic and osteoporotic patients

The objective was to confirm the finding of "Bone microstructure is similar in osteopenic an... more The objective was to confirm the finding of "Bone microstructure is similar in osteopenic and osteoporotic patients with femoral neck fracture." obtained in previous "light microscopy study", which was new and important data. Fourteen patients (5 males, 9 females) who were admitted with proximal femoral fracture following low energy trauma (patients who participated in the light microscopy study) were included. The patients were divided into two groups based on the bone mineral density (BMD) measurement, including osteopenic group (n=7, mean age 69 years; range 63 to 74 years) and osteoporotic group (n=7, mean age 74.1 years; range 67 to 78 years). Cortical and trabecular bone samples were taken from the patients who underwent endoprosthesis during partial hip arthroplasty and these samples were analyzed using transmission electron microscopy and scanning electron microscopy evaluations which are more sophisticated higher resolution techniques. The mean cortical ...

Research paper thumbnail of Effect of a chloride channel inhibitor, 5-nitro-2- (3-phenylpropylamino)-benzoate, on endothelin-1 induced vasoconstriction in rabbit basilar artery

Turkish neurosurgery, 2009

Endothelin-1 (ET-1) has been implicated in the pathophysiology of cerebral vasospasm. Chloride (C... more Endothelin-1 (ET-1) has been implicated in the pathophysiology of cerebral vasospasm. Chloride (Cl-) channels exist in vascular smooth muscle and activation of these channels leads to depolarization and contraction. The aim of the present study was to test the effect of 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), a Cl- channel antagonist, on the ET-1-induced cerebral vasospasm in rabbit basilar artery and thus investigate the contribution of Cl- channels. Thirty rabbits were divided into five groups and received intra-arterial injection of isotonic saline (Group I, n=6), ET-1 (group II, n=6), ET-1 plus NPPB (Group III, n=6), dimethylsulfate (DMSO4) (Group IV, n = 6) and NPPB (Group V, n=6). Pre and post injection basilar artery diameters were measured in each group and transmission electron microscopic investigations on basilar arteries were performed. The mean pre-injection and post-injection vessel diameters were 0.8833 mm and 0.7000 mm in ET-1 group, 0.6833 mm and 0.8500 mm ...

Research paper thumbnail of The immunohistochemical approach to determine the origin and possible function of the juxtaoral organ in dogs

Saudi medical journal, 2005

In this study, we applied immuno- histochemical techniques on the functionally little known organ... more In this study, we applied immuno- histochemical techniques on the functionally little known organ of Chievitz (juxtaoral organ [JOO]) in dogs to determine its origin and possible function. The term abortive materials of 6 Doberman dogs were used for experimental procedures in July 2002 to June 2003 at Gazi University Faculty of Medicine, Ankara, Turkey, after routine light microscopic tissue preparation, the sections were stained with Masson's trichrome stain. In order to elucidate the function-related origin of the organ, we used epidermal growth factor (EGF-r), transforming growth factor (TGF-alpha) and nerve growth factor (NGF-beta) immunohistochemical stains. We observed a very strong and widespread immunoreactivity of EGF-r and TGF-alpha on simple squamous capsular cells. We detected nerve growth factor-beta positivity in granular form both in simple squamous capsular cells and in neighboring connective tissue. However, we did not detect EGF-r reactivity on parenchymal cell...

Research paper thumbnail of 60: Fresh and Stored Botulinum Toxin-A on Muscle and Nerve Ultrastructure: An Electron Microscopic Study

Plastic and Reconstructive Surgery, 2006

Research paper thumbnail of High frequency resonant DC link PWM inverter

Proceedings of MELECON '94. Mediterranean Electrotechnical Conference, 1994

PWM inverters have been used in industry to control voltage, frequency and harmonics. However the... more PWM inverters have been used in industry to control voltage, frequency and harmonics. However the switching devices used in PWM inverters have high switching losses due to the hard switching configuration. Therefore, high frequency resonant DC link inverters have been proposed to reduce the switching losses of power devices. This paper reports a simulation developed for the use of PWM

Research paper thumbnail of Nonlinear modelling of a switched reluctance drive based on neural networks

Proceedings of MELECON '94. Mediterranean Electrotechnical Conference, 1994

Abstruct -Switched Reluctance Motors (SRMs) are almost always operated within the saturation regi... more Abstruct -Switched Reluctance Motors (SRMs) are almost always operated within the saturation region for a very large operation region. This yields very strong nonlineardies, which makes it very difF~cult to derive a comprehensive mathematical model for the behaviour of the machine. Artificial Neural Networks (ANNs) are have been used to overcome such problems. This paper preseots ANN as a new tool to handle one of the key problems in an SRM based drive system. A back propagation algorithm is used to train the network. To explore the validay of the proposed technique, the results of A N N s were canpared with tbe m l y " I results. The comparison between these results have validated the applicability of the proposed method.

Research paper thumbnail of Modelling of a nonlinear switched reluctance drive based on artificial neural networks

Proceedings of 5th International Conference on Power Electronics and Variable-Speed Drives, 1994

Switched Reluctance Motors (SRMs) are increasingly popular machines in electrical drives, whose p... more Switched Reluctance Motors (SRMs) are increasingly popular machines in electrical drives, whose performances are directly related to their operating condition. Their dynamic characteristics vary as condition change. Recently, several methods of modelling of the magnetic saturation of SRMs have been proposed. However, the SRM is nonlinear and cannot be adequately described by such models. Artificial Neural Networks (ANNs) may be used to overcome this problem. This paper presents a method which uses backpropagation algorithm to handle one of the modelling problems in an switched reluctance motor. The simulated waveforms of a phase current are compared with those obtained from a real switched reluctance commercial motor. Experimental results have validated the applicability of the proposed method.

Research paper thumbnail of Dose-related immunohistochemical and ultrastructural changes after oral methylphenidate administration in cerebrum and cerebellum of the rat

World Journal of Biological Psychiatry, 2009

Methylphenidate is a piperidine derivative and is the drug most often used to treat attention def... more Methylphenidate is a piperidine derivative and is the drug most often used to treat attention deficit/hyperactivity disorder of children and young adults. Our aim is to investigate dose-dependent dopamine-2 receptor and glial fibrillary acidic protein expression and ultrastructural changes of the rat brain, to demonstrate possible toxicity of the long-term and high dose use of the methylphenidate. In this study, 27 female prepubertal Wistar albino rats, divided into three different dose groups (5, 10 and 20 mg/kg) were treated orally with methylphenidate dissolved in saline solution for 5 days per week during 3 months. At the end of the third month, tissues were removed and sections were collected for immunohistochemical and ultrastructural studies. We believe that methylphenidate causes dose-related activation of the dopaminergic system in several brain regions especially in ventral tegmental area and also causing neuronal degeneration and capillary wall structural changes such as basal membrane thickness and augmentation of the pinostatic vesicle in the endothelial cells. Also, increased dose of Ritalin is inducing astrocytes hypertrophy especially astrogliosis in pia-glial membrane and this is the result of the degenerative changes in prefrontal cortex region due to high dose methylphenidate administration. The dose-related accumulation of the astrocytes in capillary wall might well be a consequence of the need for nutrition of the neuronal tissue, due to transport mechanism deficiency related to neuronal and vascular degeneration. Thus, we believe that the therapeutic dose of methylphenidate must be kept in minimum level to prevent ultrastructural changes.

Research paper thumbnail of Innervation of the Rat Anterior Abdominal Wall as Shown by Modified Sihler’s Stain

Medical Principles and Practice, 2006

The purpose of this study was to use the modified Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;... more The purpose of this study was to use the modified Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s staining technique to demonstrate detailed distribution of the rat anterior abdominal wall nerves and test the value of Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s technique in demonstrating such a complex muscle-nerve relationship. The anterior abdominal walls of 5 Wistar rats were isolated by making a deep incision from the costal arches on each side down to the inguinal region and processed using a modified Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s stain technique. This technique was successfully applied to visualize the innervation of the anterior abdominal wall muscles of the rat. The segmental nerves of T6-L1 and their terminal branches were shown and possible motor and sensory fibers identified. This technique is valuable in understanding the complex nature of final branching of the nerve endings, and it may be useful for studying experimental nerve models.

Research paper thumbnail of Effects of chitosan and platelet-rich plasma on facial nerve regeneration in an animal model

European Archives of Oto-Rhino-Laryngology, 2021

Purpose There is still no widely-accepted local agent proven to be effective in nerve regeneratio... more Purpose There is still no widely-accepted local agent proven to be effective in nerve regeneration. We aimed to investigate the effects of chitosan gel and platelet-rich plasma Materials and methods Electrophysiological measurements were performed before and immediately after injury. The injured nerves were covered with spongostan impregnated with the following agents: Group 1 (Control Group): Saline at a dose of 50 µl; Group 2: Chitosan (CHT) at a dose of 50 µl; Group 3: PRP at a dose of 50 ml; and Group 4: a solution of CHT with PRP (1:1). The final measurements were performed after 3 weeks and the injured nerve of each rat was removed. Results There were statistically-significant differences between the groups regarding the measurements of the after-treatment values of stimulus threshold (p < 0.05). The best improvement in electrophysiological measurement and histopathological evaluation was found in Group 4 (CHT-PRP). Conclusion Chitosan gel has a positive effect on nerve healing and applying it along with PRP can enhance the effect of chitosan.

Research paper thumbnail of Is there any link between oxidative stress and lung involvement due to inflammatory bowel disease: an experimental study

Hepato-gastroenterology

Lung involvement due to inflammatory bowel disease (IBD) is frequent, however the pathogenic mech... more Lung involvement due to inflammatory bowel disease (IBD) is frequent, however the pathogenic mechanism is still debatable. Although the evidence of inflammation in colonic and lung tissue has been documented, the possible effect of oxidative stress in lung tissue has not been evaluated to date. We sought to assess the effects of oxidant/antioxidants on lung tissue in a model of experimental colitis. Colitis was induced with intra-colonic administration of 4% acetic acid. Control group received isotonic saline. Serum and lung tissue markers of oxidative stress were explored. Serum total oxidant status was significantly higher in the colitis group than the controls while total antioxidant status was similar. The determinants of oxidants including lipid peroxidation assay and myeloperoxidase activity were significantly higher in the lung tissue of the colitis group whereas the indicators of antioxidant capacity determined as superoxide dismutase, catalase, glutathione and glutathione p...

Research paper thumbnail of Ultrastructural Damage in Vascular Endothelium in Rats Treated with Paclitaxel and Doxorubicin

Ultrastructural Pathology, 2006

Endothelium is the first physiological barrier between blood and tissues and can be injured by ph... more Endothelium is the first physiological barrier between blood and tissues and can be injured by physical or chemical stress, particularly by the drugs used in the cancer therapy. Paclitaxel and doxorubicin are frequently used anticancer drugs and their cardiac side effects are well observed in clinical setting. Their side effects on the endothelium are still not clear enough. There are few investigations assessing the damages elicited by the combination use of chemotherapy agents in animal experimental models. The purpose of this study was to examine and compare the side effects of doxorubicin and paclitaxel on endothelium in vivo. The drugs were administered weekly to rats via intraperitoneal injections singly or in combinations. Lastly, aorta endothelium was examined. The most familiar parts of the aorta endothelium are the nucleus, free ribosomes, Weibel-Palada granules, plasmalemmal vesicles, and clear basement membrane. Examination of the endothelium and the related structures revealed some clear degenerative findings. Notably, administration of a paclitaxel and doxorubicin combinations caused the most dramatic change in ultrastructure, which may disrupt many functions of the endothelium.

Research paper thumbnail of 253 Caspase 3 Activity in HCG Treated Descended and Undescended Rat Testes

The Journal of Urology, 2011

Research paper thumbnail of Motor Neurotization by Segmental Epineurectomy and Implantation: Lateral Muscular Neurotization

Journal of Reconstructive Microsurgery, 2008

In this study, we aimed to develop a new muscular neurotization technique, in which transection o... more In this study, we aimed to develop a new muscular neurotization technique, in which transection of the donor nerve is avoided. We investigated the outcome of insertion of the donor nerve within the denervated muscle following segmentary epineurectomy (lateral muscular neurotization). Thirty-five male Wistar rats were evaluated in five groups, including sham control, denervation control, denervation combined with segmentary epineurectomy, direct muscular neurotization, and lateral muscular neurotization. Electromyography, muscle weight measurements, and histological evaluations were performed at postoperative months 2 and 3. The denervation group was statistically successful for denervation as compared with the sham control group for all parameters. The lateral neurotization group was successful in preventing muscle atrophy and gaining reinnervation in electromyographic, histological, and weight parameters. The direct neurotization group was also successful in histological and weight parameters. Lateral muscular neurotization is promising because it does not interrupt the fascicular integrity and is successful in reinnervation; therefore, it seems to be a good alternative for direct muscular neurotization.

Research paper thumbnail of The effect of surgical and chemical denervation on ischaemia/reperfusion injury of skeletal muscle

Journal of Plastic, Reconstructive & Aesthetic Surgery, 2012

Research paper thumbnail of Effect of Platelet-Rich Plasma and Fibrin Glue on Healing of Critical-Size Calvarial Bone Defects

Journal of Craniofacial Surgery, 2009

Despite the insufficient number of experimental studies, platelet-rich plasma (PRP) including hig... more Despite the insufficient number of experimental studies, platelet-rich plasma (PRP) including high amounts of growth factors is introduced to clinical use rapidly. The aim of this study was to compare the effects of PRP and platelet-poor plasma (PPP) on healing of critical-size bone defects.Bilateral full-thickness, critical-size bone defects were created in the parietal bones of 32 rabbits, which had been studied in 4 groups. Saline, thrombin solution, PPP, and PRP were applied to the created defects before closure. Radiologic defect area measurement results at 0, 4, and 16 weeks were compared between the groups. In addition, densities of the newly formed bones at 16th week were studied. Histologic parameters (primary and secondary bone trabecula, neovascularization, and bone marrow and connective tissue formation) were compared between 4- and 16-week groups.More rapid decrease in defect size was observed in groups 3 and 4 than in groups 1 and 2, both in the 4th and 16th weeks. Newly formed bone densities were also found to be higher in these 2 groups. New bone formation was detected to be more rapid considering histologic parameters, in groups 3 and 4 at 4th and 16th weeks.Study demonstrates that PRP and PPP might have favorable effects on bone healing. Although we cannot reveal any statistical difference between these 2 substances considering osteoinductive potential, PRP group has demonstrated superior results compared with fibrin glue group. Higher platelet concentrations may expose beneficial effects of PRP.

Research paper thumbnail of What Wrapped Perichondrial and Periosteal Grafts Offer as Regenerators of New Tissue

Journal of Craniofacial Surgery, 2006

The major goals in contour restoration procedures are to re-establish the desired contour with th... more The major goals in contour restoration procedures are to re-establish the desired contour with the use of resilient and durable materials that can be easily found and harvested. Cartilage grafts are commonly used for these purposes though they often possess a problem of donor site morbidity and shortage of quantity. The neo-cartilage formation capacities of both perichondrium and periosteum are well-known. We aimed to optimize both the amount and quality of the newly forming tissue from perichondrial and periosteal grafts. For this purpose the grafts were wrapped on themselves. Placement of oxidized regenerated cellulose (ORC) within graft layers was performed in two groups with the aim of giving support to the regenerating tissue, and increasing the connective tissue formation within the graft layers. Three-month-old New Zealand white rabbits were used. Group 1 ear perichondrial, and Group 2 calvarium periosteal grafts of 1.4 x 2.4 cm were harvested, folded on themselves, and sutured at the edges to create closed pockets. 0.8 x 0.8 cm sized ORC sheets were placed inside the pockets before wrapping in Group 3 perichondrial and Group 4 periosteal grafts. 0.2-mL autogenous blood was injected in each pocket. All grafts were transplanted under the abdominal muscle fascia, and harvested after 6 weeks. Volumes and weights of wrapped perichondrial grafts were higher than their periosteal counterparts either with or without the inclusion of ORC. Grafts with ORC (Groups 3 and 4) were heavier than the grafts lacking ORC (Groups 1 and 2), in a statistically significant manner (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/= 0.01). Histologically, the inclusion of ORC in both perichondrial and periosteal grafts resulted in an increased amount of fibrosis, yet did not preclude neo-cartilage formation.

Research paper thumbnail of Could nephrotoxicity due to colistin be ameliorated with the use of N-acetylcysteine?

Intensive Care Medicine, 2011

Research paper thumbnail of An ultrastructural investigation in stomach epithelial cells of mice during pregnancy and early lactation

Acta gastro-enterologica Belgica

In this study, stomach epithelial cells from adult nonpregnant, pregnant lactating mice were exam... more In this study, stomach epithelial cells from adult nonpregnant, pregnant lactating mice were examined by histochemical, immunohistochemical and ultrastructural methods. Tissue samples taken from different groups were stained with haematoxylin-eosin and PAS-alcian blue and semithin sections were stained with toluidin blue for light microscopic examination. For ultrastructural examination ultrathin sections were stained with uranyl acetate and lead citrate. Additionally, by applying immunoperoxidase method, the distribution of EGF receptors of all groups was studied. We concluded that in the pregnant mice, stomach surface had lower mucus than the nonpregnant group. The acid content was balanced in active and inactive parietal cells. Examination results of lactating mice were similar to the results obtained from nonpregnant and pregnant mice.

Research paper thumbnail of Effect of platelet-rich plasma on peripheral nerve regeneration

Journal of Reconstructive Microsurgery

Activated platelets release various growth factors, some of which are recognized to improve nerve... more Activated platelets release various growth factors, some of which are recognized to improve nerve regeneration. This study evaluated the effect of platelet-rich plasma (PRP) in end-to-end neurorrhaphy. A total of 45 Wistar rats were used, with the initial five used for PRP preparation. The right hind limbs were used as experimental, with the left as control. The animals were treated in five groups. Group A (n = 4): The right sciatic nerve was dissected only from the sciatic notch to the bifurcation. In all other groups, the nerve was sharply transected and repaired with: group B (n = 8): two sutures; group C (n = 8): six sutures; group D (n = 10): two sutures and PRP; and group E (n = 10): six sutures and PRP. Groups D and E were compared with groups B and C, respectively. Group E had a shorter latency time in electromyography ( P < 0.01) and a thicker myelin layer in the histological evaluation ( P < 0.003) in comparison with group C. These positive effects of PRP were not de...

Research paper thumbnail of Transmission and scanning electron microscopy confirm that bone microstructure is similar in osteopenic and osteoporotic patients

The objective was to confirm the finding of "Bone microstructure is similar in osteopenic an... more The objective was to confirm the finding of "Bone microstructure is similar in osteopenic and osteoporotic patients with femoral neck fracture." obtained in previous "light microscopy study", which was new and important data. Fourteen patients (5 males, 9 females) who were admitted with proximal femoral fracture following low energy trauma (patients who participated in the light microscopy study) were included. The patients were divided into two groups based on the bone mineral density (BMD) measurement, including osteopenic group (n=7, mean age 69 years; range 63 to 74 years) and osteoporotic group (n=7, mean age 74.1 years; range 67 to 78 years). Cortical and trabecular bone samples were taken from the patients who underwent endoprosthesis during partial hip arthroplasty and these samples were analyzed using transmission electron microscopy and scanning electron microscopy evaluations which are more sophisticated higher resolution techniques. The mean cortical ...

Research paper thumbnail of Effect of a chloride channel inhibitor, 5-nitro-2- (3-phenylpropylamino)-benzoate, on endothelin-1 induced vasoconstriction in rabbit basilar artery

Turkish neurosurgery, 2009

Endothelin-1 (ET-1) has been implicated in the pathophysiology of cerebral vasospasm. Chloride (C... more Endothelin-1 (ET-1) has been implicated in the pathophysiology of cerebral vasospasm. Chloride (Cl-) channels exist in vascular smooth muscle and activation of these channels leads to depolarization and contraction. The aim of the present study was to test the effect of 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), a Cl- channel antagonist, on the ET-1-induced cerebral vasospasm in rabbit basilar artery and thus investigate the contribution of Cl- channels. Thirty rabbits were divided into five groups and received intra-arterial injection of isotonic saline (Group I, n=6), ET-1 (group II, n=6), ET-1 plus NPPB (Group III, n=6), dimethylsulfate (DMSO4) (Group IV, n = 6) and NPPB (Group V, n=6). Pre and post injection basilar artery diameters were measured in each group and transmission electron microscopic investigations on basilar arteries were performed. The mean pre-injection and post-injection vessel diameters were 0.8833 mm and 0.7000 mm in ET-1 group, 0.6833 mm and 0.8500 mm ...

Research paper thumbnail of The immunohistochemical approach to determine the origin and possible function of the juxtaoral organ in dogs

Saudi medical journal, 2005

In this study, we applied immuno- histochemical techniques on the functionally little known organ... more In this study, we applied immuno- histochemical techniques on the functionally little known organ of Chievitz (juxtaoral organ [JOO]) in dogs to determine its origin and possible function. The term abortive materials of 6 Doberman dogs were used for experimental procedures in July 2002 to June 2003 at Gazi University Faculty of Medicine, Ankara, Turkey, after routine light microscopic tissue preparation, the sections were stained with Masson's trichrome stain. In order to elucidate the function-related origin of the organ, we used epidermal growth factor (EGF-r), transforming growth factor (TGF-alpha) and nerve growth factor (NGF-beta) immunohistochemical stains. We observed a very strong and widespread immunoreactivity of EGF-r and TGF-alpha on simple squamous capsular cells. We detected nerve growth factor-beta positivity in granular form both in simple squamous capsular cells and in neighboring connective tissue. However, we did not detect EGF-r reactivity on parenchymal cell...

Research paper thumbnail of 60: Fresh and Stored Botulinum Toxin-A on Muscle and Nerve Ultrastructure: An Electron Microscopic Study

Plastic and Reconstructive Surgery, 2006

Research paper thumbnail of High frequency resonant DC link PWM inverter

Proceedings of MELECON '94. Mediterranean Electrotechnical Conference, 1994

PWM inverters have been used in industry to control voltage, frequency and harmonics. However the... more PWM inverters have been used in industry to control voltage, frequency and harmonics. However the switching devices used in PWM inverters have high switching losses due to the hard switching configuration. Therefore, high frequency resonant DC link inverters have been proposed to reduce the switching losses of power devices. This paper reports a simulation developed for the use of PWM

Research paper thumbnail of Nonlinear modelling of a switched reluctance drive based on neural networks

Proceedings of MELECON '94. Mediterranean Electrotechnical Conference, 1994

Abstruct -Switched Reluctance Motors (SRMs) are almost always operated within the saturation regi... more Abstruct -Switched Reluctance Motors (SRMs) are almost always operated within the saturation region for a very large operation region. This yields very strong nonlineardies, which makes it very difF~cult to derive a comprehensive mathematical model for the behaviour of the machine. Artificial Neural Networks (ANNs) are have been used to overcome such problems. This paper preseots ANN as a new tool to handle one of the key problems in an SRM based drive system. A back propagation algorithm is used to train the network. To explore the validay of the proposed technique, the results of A N N s were canpared with tbe m l y " I results. The comparison between these results have validated the applicability of the proposed method.

Research paper thumbnail of Modelling of a nonlinear switched reluctance drive based on artificial neural networks

Proceedings of 5th International Conference on Power Electronics and Variable-Speed Drives, 1994

Switched Reluctance Motors (SRMs) are increasingly popular machines in electrical drives, whose p... more Switched Reluctance Motors (SRMs) are increasingly popular machines in electrical drives, whose performances are directly related to their operating condition. Their dynamic characteristics vary as condition change. Recently, several methods of modelling of the magnetic saturation of SRMs have been proposed. However, the SRM is nonlinear and cannot be adequately described by such models. Artificial Neural Networks (ANNs) may be used to overcome this problem. This paper presents a method which uses backpropagation algorithm to handle one of the modelling problems in an switched reluctance motor. The simulated waveforms of a phase current are compared with those obtained from a real switched reluctance commercial motor. Experimental results have validated the applicability of the proposed method.

Research paper thumbnail of Dose-related immunohistochemical and ultrastructural changes after oral methylphenidate administration in cerebrum and cerebellum of the rat

World Journal of Biological Psychiatry, 2009

Methylphenidate is a piperidine derivative and is the drug most often used to treat attention def... more Methylphenidate is a piperidine derivative and is the drug most often used to treat attention deficit/hyperactivity disorder of children and young adults. Our aim is to investigate dose-dependent dopamine-2 receptor and glial fibrillary acidic protein expression and ultrastructural changes of the rat brain, to demonstrate possible toxicity of the long-term and high dose use of the methylphenidate. In this study, 27 female prepubertal Wistar albino rats, divided into three different dose groups (5, 10 and 20 mg/kg) were treated orally with methylphenidate dissolved in saline solution for 5 days per week during 3 months. At the end of the third month, tissues were removed and sections were collected for immunohistochemical and ultrastructural studies. We believe that methylphenidate causes dose-related activation of the dopaminergic system in several brain regions especially in ventral tegmental area and also causing neuronal degeneration and capillary wall structural changes such as basal membrane thickness and augmentation of the pinostatic vesicle in the endothelial cells. Also, increased dose of Ritalin is inducing astrocytes hypertrophy especially astrogliosis in pia-glial membrane and this is the result of the degenerative changes in prefrontal cortex region due to high dose methylphenidate administration. The dose-related accumulation of the astrocytes in capillary wall might well be a consequence of the need for nutrition of the neuronal tissue, due to transport mechanism deficiency related to neuronal and vascular degeneration. Thus, we believe that the therapeutic dose of methylphenidate must be kept in minimum level to prevent ultrastructural changes.

Research paper thumbnail of Innervation of the Rat Anterior Abdominal Wall as Shown by Modified Sihler’s Stain

Medical Principles and Practice, 2006

The purpose of this study was to use the modified Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;... more The purpose of this study was to use the modified Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s staining technique to demonstrate detailed distribution of the rat anterior abdominal wall nerves and test the value of Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s technique in demonstrating such a complex muscle-nerve relationship. The anterior abdominal walls of 5 Wistar rats were isolated by making a deep incision from the costal arches on each side down to the inguinal region and processed using a modified Sihler&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s stain technique. This technique was successfully applied to visualize the innervation of the anterior abdominal wall muscles of the rat. The segmental nerves of T6-L1 and their terminal branches were shown and possible motor and sensory fibers identified. This technique is valuable in understanding the complex nature of final branching of the nerve endings, and it may be useful for studying experimental nerve models.