Effect of Propolis on Neurological Recovery After Experimental Spinal Cord Injury.

AIM: To examine the effect of propolis on the healing process in terms of both electrophysiological and ultrastructural parameters in a rat model of experimental spinal cord injury. MATERIAL AND METHODS: Thirty rats were divided into control, spinal cord trauma, and treated trauma groups with 10 rats per group. The rats were sacrificed after 10 days. Before sacrifice, all rats were neurologically assessed by electrophysiological monitoring, and immediately after sacrifice, the spinal cord was examined ultrastructurally by transmission electron microscopy (TEM). RESULTS: According to the electrophysiological examination, the treatment group was statistically significantly different from the trauma group. However, no statistically significant difference was found between the control and treatment groups. In terms of the TEM examination, the treatment group was significantly different from the trauma group. CONCLUSION: In this study, propolis was administered just before the induction of trauma, and the findings suggest that the use of propolis has a positive effect on the healing process. This implies that in order to prevent postoperative deficits, this treatment may be preferably applied before spinal cord surgery for trauma.

Therapeutic efficacy of folate receptor-targeted amphiphilic cyclodextrin nanoparticles as a novel vehicle for paclitaxel delivery in breast cancer.

PURPOSE: The aim of this study is to test folate-conjugated cyclodextrin nanoparticles (FCD-1 and FCD-2) as a vehicle for reducing toxicity and increasing the antitumor efficacy of paclitaxel especially for metastatic breast cancer. METHODS: For the evaluation of PCX-loaded FCD nanoparticles, animal studies were realised in terms of survival rate, tumour size, weight change, metastazis and histopathological examination. RESULTS: FCD-1 displayed significant advantages such as efficient targeting of folate receptor positive breast cancer cells and having considerably lower toxicity compared to that of Cremophor®. When loaded with paclitaxel, FCD-1 nanoparticles, which have smaller particle size, neutral zeta potential, high encapsulation efficiency and better loading capacity for controlled release, emerged as an effective formulation in terms of cytotoxicity and high cellular uptake. In an experimental breast cancer model, anticancer activity of these nanoparticles were compatible with that of paclitaxel in Cremophor® however repeated administrations of FCD-1 nanoparticles were better tolerated by the animals. These nanoparticles were able to localise in tumour site. Both paclitaxel-loaded FCD-1 and FCD-2 significantly reduced tumour burden while FCD-1 significantly improved the survival. CONCLUSIONS: Folate-conjugated amphiphilic cyclodextrin nanoparticles can be considered as promising Cremophor®-free, low-toxicity and efficient active drug delivery systems for paclitaxel.

Novel Anatomic Mapping of Pelvic Plexus at Prostatic and Periprostatic Region on Fresh Frozen Cadaveric Setting.

PURPOSE: We aimed to investigate the exact localization of neural pathway and the frequency of nerve fibers, which are located in the pelvic facial layers in the prostate and periprostatic regions. MATERIALS AND METHODS: We used four fresh frozen cadavers in this trial. Anatomical layers of anterior rectus fascia and abdominal rectus muscle were dissected to reach the retropubic area. Prostate, visceral and parietal pelvic fascia, levator ani muscle and puboprostatic ligaments were identified. Nine tissue samples, each 1x1 cm in size, were obtained from each cadaver and grouped separately. The locations of these samples are as follows. Group G I from 12 o'clock (apical region), G II from right prostatic apex, G III from 2 o'clock, G IV from right far pelvic lateral, G V from 5 o'clock, G VI from 7 o'clock, GVII from left far pelvic lateral, G VIII from 10 o'clock and G IX from left prostatic apex. Nerve distribution, frequency and diameters of these 9 groups were compared to each other. RESULTS: 36 specimens were obtained from 4 cadavers. Mean number of nerve fibers was 14.1. The number of nerve fibers in each location were not statistically different from each other (P = .9). Mean nerve diameter was 89.1 µm. Mean diameter of nerves was statistically different between groups II, III IV and VI and VIII (P = .001). No difference was seen amongst others. CONCLUSION: The distributions of nerve fibers at prostate and peri-prostatic region were homogeneous while the nerve diameters varied amongst the different regions.

Toxicity of internalized laser generated pure silver nanoparticles to the isolated rat hippocampus cells.

Silver nanoparticles (AgNPs) are the most commonly used nanoparticles (NPs) in medicine, industry and cosmetics. They are generally considered as biocompatible. However, contradictory reports on their biosafety render them difficult to accept as 'safe'. In this study, we evaluated the neurotoxicity of direct AgNP treatment in rat hippocampal slices. We produced pure uncoated AgNPs by a pulsed laser ablation method. NP characterization was performed by Ultraviolet (UV) visible spectrophotometer, scanning electron microscope, transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy. Rat hippocampal slices were treated with AgNPs for an hour. AgNP exposure of hippocampal tissue resulted in a significant decrease in cell survival in a dose-dependent manner. Our TEM results showed that AgNPs were distributed in the extracellular matrix and were taken into the cytoplasm of the neurons. Moreover, we found that only larger AgNPs were taken into the neurons via phagocytosis. This study showed that the pure AgNPs produced by laser ablation are toxic to the neural tissue. We also found that neurons internalized only the large NPs by phagocytosis which seems to be the major mechanism in AgNP neurotoxicity.

Dipyrone attenuates cerebral vasospasm after experimental subarachnoid hemorrhage in rabbits.

BACKGROUND: The purpose of this study was to evaluate the effect of the systemic administration of dipyrone in a triple subarachnoid hemorrhage (SAH) model of cerebral vasospasm in rabbits. METHODS: Experimental subarachnoid hemorrhage was induced in rabbits by injecting autologous arterial blood into the cisterna magna. Digital subtraction angiographies (DSA) were performed before and after the first experimental SAH, and at 30, 45, 60 minutes and 72 hours after the first drug administration to measure the diameter of basilar artery. Intracisternal blood injections were repeated 24 and 48 hours after the first injection. Dipyrone (N.=20) or 0.9% NaCl (N.=20) was administered intravenously after initial SAH induction and repeated at 8-hour intervals intramuscularly. After sacrificing by perfusion-fixation, basilar arteries were removed and sectioned for transmission electron microscopic (TEM) examination. RESULTS: The average basilar artery diameter measured by DSA was 724±19 µm in the control, and 686±29 µm in treatment group before SAH. After SAH, mean basilar artery diameters decreased to 71% and 68% of their basal values, respectively. Dipyrone significantly attenuated the basilar artery diameter at one and 72 hours after the first drug administration, in comparison to the control group. TEM studies showed more edema in the endothelial cells of the basilar arteries of the control group when compared to the treatment group. CONCLUSIONS: Dipyrone showed a beneficial effect in autologous blood-induced basilar artery vasospasm in rabbits. These data support the idea that dipyrone can be a potential candidate drug to be tested in patients suffering from cerebral vasospasm secondary to subarachnoid hemorrhage.

Histologic alterations in tetralogy of Fallot.

BACKGROUND: This study was performed to investigate the pre-existing histologic alterations at the time of complete repair in patients with tetralogy of Fallot (TOF) and evaluate their effects on the early postoperative outcomes. METHODS: Fourteen patients, seven with acyanotic TOF (SO2 > 90, group I) and seven with cyanotic TOF (SO2 < 90, group II), undergoing complete repair, were enrolled. Right ventricular biopsies were examined for cardiomyocyte injury and fibrosis by light microscopy and mitochondrial injury by electron microscopy. The association of the severity of histologic alterations and postoperative inotrope use, intensive care unit, and in-hospital stays were evaluated. RESULTS: Compared with group I, patients in group II had a higher inotrope score (p = 0.03) and longer intensive care unit (p = 0.01) and in-hospital stays (p = 0.04). Cardiomyocyte injury and mitochondrial damage scores were higher in group II (p = 0.01 and p = 0.02, respectively). Fibrosis was detected in all specimens but was more severe in group II (p < 0.001). However, we could not demonstrate any correlation between histologic alterations and early surgical outcomes. The history of spell was significantly associated with worse early surgical outcomes (p < 0.05). CONCLUSIONS: Pre-existing cardiomyocyte injury accompanied by mitochondrial damage and fibrosis were more pronounced in cyanotic TOF patients. Early repair may prevent the development of histopathologic alterations in these patients.

The effect of tacrolimus on facial nerve injury: Histopathological findings in a rabbit model.

HYPOTHESIS: Tacrolimus helps healing of facial nerve injury. BACKGROUND: Positive effects of tacrolimus on axon regeneration and healing of injured peripheral nerves (eg. sciatic nerve) have been reported in the literature. Tacrolimus may be an additional treatment method that could improve the nerve healing after surgical treatment of cut injury of facial nerve. METHODS: 20 New Zealand rabbits were randomly separated into control and study groups of 10. In control group, no medical treatment was given after facial nerve anastomosis, and the animals were followed up for 2months. In the study group rabbits were given 1mg/kg/day tacrolimus subcutaneously for 2months after the facial nerve anastomosis. The histopathologic findings of axon regeneration like axon myelination were analyzed in both groups under electron and light microscopy. The data obtained in the groups were compared. RESULTS: Greater axon diameters, thicker myelin sheaths, and higher total number of myelinated axons were found in the tacrolimus group, suggesting better regeneration in this group when compared to the control group. There was less vacuolar degeneration in the study group. All these findings suggest that tacrolimus positively affects healing after facial nerve anastomosis. CONCLUSION: The results of this study indicate that tacrolimus has favorable effects on the healing process of the facial nerve after end-to-end anastomosis. Tacrolimus may be a promising agent in the future for nerve regeneration following traumatic facial paralysis surgery.

Antitumor Efficacy of Bacillus Calmette-Guerin Loaded Cationic Nanoparticles for Intravesical Immunotherapy of Bladder Tumor Induced Rat Model.

For bladder cancer, intravesical chemo/immunotherapy is widely used as adjuvant therapy after surgical transurethral resection. Bacillus Calmette-Guerin (BCG) is a live attenuated Mycobacterium of the same family as tuberculosis, that is capable of inducing a local inflammatory response upon instillation into the bladder. Intravesical therapy with BCG has proved to be more effective in the prophylaxis and treatment of superficial bladder tumors than most chemotherapeutic agents used for the same indication. However, compared to intravesical chemotherapy, BCG immunotherapy provokes more pronounced local and systemic reactions. In addition to the commonly induced granulomatous inflammatory changes in the bladder, which produce irritative symptoms, this therapy may cause systemic side effects varying from mild malaise and fever to, in rare instances, life-threatening or fatal sepsis. Nanoparticles with positive surface charge and mucoadhesive properties were developed to overcome these side effects. Hence, the aim of this study was to optimize and evaluate cationic chitosan (CS) nanoparticles encapsulating BCG in terms of antitumor efficacy after intravesical administration in bladder tumor, induced in rat model. It was found that nanoparticle formulations of 269-375 nm in size can be produced with 42% encapsulation efficiency. The zeta potential was positive and was suitable for intravesical administration. Antitumor efficacy was determined over the parameters of histopathological evaluation, survival rate and mean bladder weight in comparison to treatment with commercial BCG solution. Concerning survival rates, BCG-loaded chitosan nanoparticles resulted in significantly longer survival than BCG commercial product (up to 86 days of survival with no systemic side effects). When compared to healthy bladder weight averages, all groups (especially BCG commercial solution) showed higher bladder weights confirming tumor formation. Histopathological findings confirmed antitumor activity in all treatment groups and optimum findings were observed in groups treated with CS nanoparticles encapsulating BCG. At the same time, significant nanoparticle accumulation in bladder tissues was observed especially for BCG-loaded CS group. In this study, it was clearly observed that cationic CS nanoparticles provide a significantly improved perspective in intravesical immunotherapy of bladder tumors.

Evaluation of the effect of changes in dose rate on rat lung cells.

The aim of this study is to evaluate the effect of dose rate (DR) on lung tissue. The rats included in the study were randomly grouped into 3 groups: Group (G) 1 was defined as control group, and in this group rats were sham irradiated. G2 was the group receiving a single dose of 12 Gy in DR of 300 monitor unit (MU)/min. G3 was the group receiving a single dose of 12 Gy in DR of 600 MU/min. Radiotherapy (RT) was applied under general anesthesia with 6-MV photon beams to both lungs. At the 6th and 16th week of the RT, animals from each group were killed for light and electron microscopy evaluation. We evaluated the scores of each group in the 6th and the 16th week and found that in G2, there were significant increases in the perivascular fibrosis (P = .018), interstitial fibrosis (P = .002), total inflammation (P = .040), and total fibrosis (P = .003) scores. In G3, we found statistically significant increases in perivascular fibrosis (P = .001), interstitial fibrosis (P = .002), and total fibrosis scores (P = .029). There was no significant difference in the total inflammation score in G3 (P = .225). When we compare G2 and G3 in the 6th week, we found significant increase in the interstitial thickening (P = .039) and total inflammation (P = .035) scores in G3. Dose rate per fraction may have an impact on normal tissue toxicity. The prominent effect of increased DR in lung tissue is fibrosis which should be kept in mind, especially in cases where higher doses per fraction are used.

An experimental comparison of the effects of propolis, curcumin, and methylprednisolone on crush injuries of the sciatic nerve.

BACKGROUND: Propolis and curcumin have antioxidant, anti-inflammatory, immunomodulatory, and neuroprotective features. The goal of this study was to determine the effects of propolis and curcumin on nerve healing in rat sciatic nerve crush injuries and to compare these effects with results obtained using steroid treatment. METHODS: In the sham group, the right sciatic nerves of rats were dissected and exposed, and the skin was closed without any additional manipulation. In the control group (group C), after the right sciatic nerves of rats were exposed, crush damage was inflicted using a surgical clamp. In the control-methylprednisolone group, crush injuries were inflicted on sciatic nerves as in group C. After injury, 1-mg/kg methylprednisolone was administered daily for 6 days and was then tapered for 4 days. In the curcumin group, crush injuries were inflicted on sciatic nerves as in group C. Then, 100-mg/kg curcumin was given every day. In the propolis group, crush injuries were inflicted on sciatic nerves as in group C. Then, 200-mg/kg propolis was given every day. Rats were evaluated after 28 days using functional (walking track analysis and electrophysiological measurements), histomorphometric, electron microscopic, and muscle weight measurements. RESULTS: Compared to the control groups, the curcumin and propolis groups had better functional (walking track analysis and electrophysiological) results after experimental peripheral nerve crush injury. CONCLUSIONS: Curcumin and propolis, 2 traditional drugs, had a positive effect on nerve crush injuries. We are convinced that they can be used to support routine treatment in such nerve injuries.

Cationic core-shell nanoparticles for intravesical chemotherapy in tumor-induced rat model: safety and efficacy.

Mitomycin C (MMC) has shown potent efficacy against a wide spectrum of cancers and is clinical first choice in superficial bladder tumors. However, intravesical chemotherapy with MMC has been ineffective due to periodical discharge of the bladder and instability of this drug in acidic pH, both resulting in high rate of tumor recurrence and insufficiency to prevent progression. Nanocarriers may be a promising alternative for prolonged, effective and safe intravesical drug delivery due to their favorable size, surface properties and optimum interaction with mucosal layer of the bladder wall. Hence, the aim of this study was to evaluate and optimize cationic core-shell nanoparticles formulations (based on chitosan (CS) and poly-ϵ-caprolactone (PCL)) in terms of antitumor efficacy after intravesical administration in bladder tumor induced rat model. Antitumor efficacy was determined through the parameters of survival rate and nanoparticle penetration into the bladder tissue. Safety of the formulations were evaluated by histopathological evaluation of bladder tissue as well as observation of animals treated with MMC bound to nanoparticles. Results indicated that chitosan coated poly-ϵ-caprolactone (CS-PCL) nanoparticles presented the longest survival rate among all treatment groups as evaluated by Kaplan-Meier plotting. Histopathological evaluation revealed that cationic nanoparticles were localized and accumulated in the bladder tissue. As intravesical chemotherapy is a local therapy, no MMC was quantified in blood after intravesical instillation indicating no systemic uptake for the drug which could have subsequently led to side effects. In conclusion, core-shell type cationic nanoparticles may be effective tools for the intravesical chemotherapy of recurrent bladder tumors.

Comparison of herbal-based and synthetic hemostatic agents for efficacy on a rat partial nephrectomy model. Experimental study.

OBJECTIVE: To compare the efficacy of herbal based and synthetic hemostatic agents in partial nephrectomy. METHODS: Our experimental study was carried out at the Ankara Training and Research Hospital, Ankara, Turkey between May and November 2012. Twenty rats were randomly divided into 4 groups. Intracorporeal sutures (group K), TachoSil (group T), HaemoCer (group H), and Ankaferd Blood Stopper (group A) were used to achieve hemostasis in partial nephrectomy. Warm ischemia time (WIT), hemostasis time (HT), and blood loss for all groups were measured. The specimens were examined histopathologically and electron microscopically after sacrificing the rats. RESULTS: The fastest hemostasis was detected in group T, followed by group H, and group A. The WIT and HT were significantly different for all groups (p<0.001). The greatest blood loss was found in group K. The histopathologic examination revealed that the giant cell reaction in group K was significantly more than in group H and group A (p<0.001). No pathologic findings were observed in the ultrastructural examination of specimens taken from group K. On ultrastructural examination of group T, tubule cells had many vacuoles in their cytoplasm with marked intracellular edema. Ultrastructural findings for groups H and A were similar. CONCLUSION: At the histopathologic and ultrastructural levels, herbal-based hemostatic agents had a positive impact on renal tissue and glomerular function when applied during partial nephrectomy.

Alterations of the anterior lens capsule in vitrectomized eyes with silicone oil tamponade.

BACKGROUND AND OBJECTIVE: To investigate the electron microscopic findings of the anterior lens capsule in vitrectomized eyes with silicone oil tamponade. PATIENTS AND METHODS: Ten eyes of 10 consecutive patients aged 39 to 74 years who had cataract surgery combined with silicone oil removal from December 2006 to May 2009 were included in the study. The control group included 10 patients with cataract extraction and intraocular lens implantation without history of systemic or other ocular disease. All anterior capsules underwent electron microscopic examination of the anterior lens capsule. RESULTS: During the capsulorhexis, the anterior lens capsule was removed. In the silicone oil tamponade group, silicone oil droplets were detected on the posterior surface of the anterior lens capsule in 5 cases (50%) and surface irregularities, pits, and depressions were present in the posterior surface of the anterior lens capsules in all cases. CONCLUSION: Silicone oil droplets may infiltrate the lens capsule, especially in diabetic patients. Surface irregularities may be associated with posterior fibrous pseudometaplasia produced by lens epithelial cells under the anterior lens capsule.

Methothrexate attenuates early neutrophil infiltration and the associated lipid peroxidation in the injured spinal cord but does not induce neurotoxicity in the uninjured spinal cord in rats.

BACKGROUND: The goal of most acute therapies for spinal cord injury (SCI) in humans include attenuation of the early inflammatory response and may limit the extent of tissue injury and the consequent disability. OBJECTIVE: The purpose of this study was to investigate the early effects of methothrexate (MTX) treatment on myeloperoxidase (MPO) activity, malondialdehyde (MDA) level, and ultrastructural findings in the injured and uninjured spinal cords of rats. The effects of MTX treatment were also compared with methylprednisolone sodium succinate (MPSS) treatment. METHODS: Wistar rats were divided into seven groups: control; trauma alone (50 g/cm weight drop trauma); SCI + MPSS (30 mg/kg); SCI + low-dose (0.5 mg/kg) MTX (LDMTX); SCI + higher-dose (1 mg/kg) MTX (HDMTX); non-trauma + LDMTX; non-trauma + HDMTX. RESULTS: Administration of MTX and MPSS treatments significantly decreased MPO activity (p < 0.05) and MDA level (p < 0.05) in the first 24 h. The MTX treatments, particularly HDMTX, were more effective than MPSS in reducing MPO activity, and MTX treatments were also more effective than MPSS in reducing MDA level (p < 0.05). The MTX treatment was more protective on large- and medium-diameter myelinated axons in minimizing ultrastructural changes in the spinal-cord-injured rats, but did not induce neurotoxicity in normal spinal cord. CONCLUSION: The results of this study indicate that MTX treatment has a beneficial effect by reducing early neutrophil infiltration and the associated lipid peroxidation, and has significantly protective effects on the injured spinal cord tissue in the first 24 h after SCI. Given the anti-inflammatory properties of MTX, a single dose of MTX a week is used for non-neoplastic disease in humans, and MTX may have a beneficial role in the immediate management of acute SCI.

Nanoparticle silver ion coatings inhibit biofilm formation on titanium implants.

The formation of bacterial biofilm on the surface of implanted metal objects is a major clinical problem. The antibacterial and antifungal effect of silver ions has been long known, and seems to give silver the capability to inhibit biofilm formation. To test the effect of silver ions, 20 New Zealand rabbits had bacteria applied to a screw insertion site at the iliac crest, and were then randomly divided into two groups: Group I, which had silver-coated screws applied, and Group II, which had uncoated titanium screws. After the rabbits were sacrificed on day 28, we examined the screws, the bone adjacent to the screws, and the liver, kidneys, brain and corneas of both groups under transmission (TEM) and scanning electron microscopy (SEM). We also analysed microbiological samples from the screw holes. All silver-coated screws, but only 10% of uncoated titanium screws, were sterile. All tissue samples appeared ultrastructurally normal in both groups. Biofilm formation was inhibited on all silver-coated screws, but all uncoated screws developed a biofilm on their surfaces. Our findings suggest that nanoparticle silver ion-coated implants are as safe as uncoated titanium screws and that they can help prevent both biofilm formation and infection.

Local administration of chitosan microspheres after traumatic brain injury in rats: a new challenge for cyclosporine--a delivery.

The major aim of this study was to evaluate the efficiency of chitosan microspheres containing cyclosporine-A (Cs-A) on mitochondrial damage in traumatic brain injury (TBI) animal model. Trauma was introduced to male Sprague-Dawley (SD) rats similar to that of modified Feeney Method. Briefly, after craniectomy in the left parietal region (5 mm). Trauma was performed by dropping 24 g metal sterile rods through a teflon guide tube (9.3 cm) on a foot plate placed over the duramater. Just after the trauma, 20 mg/kg Cs-A (Sandimmune) has been administered to the traumatised SD rats intraperitoneally (i.p.). On the other hand, only chitosan microspheres containing 10 mg/kg was implanted at the craniectomy area locally after trauma in Group E. A small piece of surgicell was placed over the craniectomy hole and the scalp incision was sutured. 24 h after injury and the brain tissues were removed intact. The results were evaluated through lipid peroxidation ratio and ultrastructural grading system. The statistical comparisons were evaluated by using Mann Whitney- U test at the significance level p = 0.05. The lipid peroxidation ratios of sham (78.4 +/- 6.0 nmol/g tissue) and vehicle (80.2 +/- 10.6 nmol/g tissue) were significantly increased 24 h after TBI. However, for treatment groups (i.p. Cs-A; 20 mg/kg) and (10 mg/kg Cs-A in microspheres), statistically significant lower lipid peroxidation ratios were determined as 53.5 +/- 9.7 and 47.9 +/- 8.1 nmol/g tissue, respectively (p < 0.05). The mitochondrial damage scores of the treatment groups were recorded as 21.7 +/-2.6 and 19.4 +/- 3.9 for Group D and Group E, respectively. Both of these scores of the treatment groups were found as significantly different from the sham and vehicle groups' scores individually. The implantation of microsphere formulation has provided a better efficiency in keeping the uniformity of mitochondrial structure in this complex cascade of events after TBI.

Effect of granulocyte-colony stimulating factor on spinal cord tissue after experimental contusion injury.

The purpose of this study was to investigate the early effects of granulocyte-colony stimulating factor (G-CSF) on myeloperoxidase (MPO) activity, lipid peroxidation (LPO) and ultrastructural findings in rats after spinal cord injury (SCI). We also compared the effects of G-CSF and methylprednisolone sodium succinate (MPSS). Wistar rats were divided into four groups: control, SCI alone (50 g/cm weight drop trauma), SCI+MPSS (30 mg/kg), and SCI+G-CSF (50 µg/kg). Administration of G-CSF and MPSS significantly decreased LPO (p < 0.05) and MPO activity (p < 0.05) in the first 24 hours. MPSS was more effective than G-CSF in reducing LPO (p < 0.05) and in minimizing ultrastructure changes. The results of this study indicate that G-CSF exerts a beneficial effect by decreasing MPO activity and LPO and may reduce tissue damage in the first 24 hours after SCI. Our findings do not exclude the possibility that G-CSF has a protective effect on spinal cord ultrastructure after the first 24 hours following SCI.

Effect of use of slow release of bone morphogenetic protein-2 and transforming growth factor-Beta-2 in a chitosan gel matrix on cranial bone graft survival in experimental cranial critical size defect model.

Bone grafts, used for providing structural integrity of cranial vault remodeling, could not always integrate with the remaining bone structures. All efforts are focused on increasing incorporation of the applied bone grafts. Allografts were covered by chitosan so that slow release of bone morphogenetic protein-2 (BMP-2) and Transforming growth factor-beta-2 (TGF-beta-2) was achieved. Two hundred forty Wistar-Albino rats were distributed equally in 8 study groups. Study groups were designed as; defect group, autograft group, allograft group, chitosan group, allograft + chitosan, TGF-beta-2 group, BMP-2 group, and TGF-Beta-2 +BMP-2 group. Bone biopsies were obtained at second, eight, and 14th weeks. Bone regeneration was evaluated by morphologic studies detecting histologic bone healing and radiologic studies detecting bone density. Histologic findings were evaluated in 2 categories; tissue response to the implant and defect healing. Additionally, scanning electron microscopy for detailed morphologic evaluation was done. Bone density of the applied scaffold and the parietal bone at the same computed tomography section were measured in Hounsfield scale and this ratio was used for densitometry evaluations. Kruskal-Wallis test was used to analyze difference among groups according to the histologic and radiologic data. Pairwise comparisons were done using Mann-Whitney U test with Bonferroni correction. P < 0.05 was considered significant. In the morphologic studies, bone regeneration in BMP-2 group was found to be compatible with bone regeneration in gold standard autograft group and even better than it within 15 days. Chitosan is a biocompatible material. TGF-Beta-2 alone is not effective enough in bone regeneration; BMP-2 alone has a positive effect in every step of bone regeneration. Combining TGF-Beta-2 with BMP-2 does not lead to a better bone regeneration than using BMP-2 alone. A synergistic effect is not obtained by using these 2 factors together.

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

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.

Ultrastructural evaluation of Pulsed Radiofrequency and Conventional Radiofrequency lesions in rat sciatic nerve.

BACKGROUND: PRF treatment has recently been described as minimally neurodestructive alternative to radiofrequency heat lesions. Patients with some pain syndromes in whom the pain could not be controlled by alternative techniques may be treated using PRF. In the present study, our main goal was to evaluate and compare the ultrastructure of peripheral nerve tissue that was heated by PRF, CRF with 42 degrees C, and CRF with 70 degrees C. METHODS: Forty-five male rats were divided into 5 groups. In PRF group and CRF with 42 degrees C group, the sciatic nerve was heated at a temperature of 42 degrees C for 120 seconds. As a positive control, some rat sciatic nerves were treated with CRF lesions at 70 degrees C. The rats were kept alive for 21 days and then killed. Tissue was evaluated with transmission electron microscope, and grading was done to the groups. RESULTS: The unmyelinated nerve fibers were ultrastructurally normal in all groups. The results of myelinated axons indicated that PRF group had better grades, and CRF with 70 degrees C group had the worst grade. Especially, comparison of the group of PRF and CRF with 42 degrees C revealed significant difference. In PRF group, none of the myelinated axons showed severe degeneration findings, and most of the damaged myelinated axons showed only separation in myelin configuration. CONCLUSIONS: PRF treatment may cause separation in myelinated axons. However, it seems that all changes were reversible. The present study supports the hypothesis that pulsed RF treatment does not rely on thermal injury of neurologic tissue to achieve its effect.