A. Aydan Köse

Protective effect of Fucoidin (a neutrophil rolling inhibitor) on ischemia reperfusion injury: Experimental study in rat epigastric island flaps

The objective of this study was to examine whether a decrease in neutrophil-mediated tissue injury using Fucoidin, a nontoxic neutrophil rolling inhibitor, would improve flap survival in an island flap model after ischemia–reperfusion. Myeloperoxidase activity (an indirect index of tissue neutrophil count) and malondialdehyde (an indicator of lipid peroxidation), the degree of neutrophil infiltration by direct counting, and macroscopic flap survival were assessed in the flap after arterial ischemia–reperfusion. Epigastric island skin flaps were elevated in 56 rats. The first group of 21 rats was subjected to 6 hours of arterial ischemia. The second group of 21 rats was subjected to 10 hours of arterial ischemia, and the rest of the rats were used as nonischemic controls (sham flaps). For inhibiting neutrophil rolling, a nontoxic polysaccharide agent—Fucoidin—was used. Each ischemic group was divided further into three subgroups: Subgroup I (control rats) received saline, subgroup II received 10 mg per kilogram Fucoidin, and subgroup III received 25 mg per kilogram Fucoidin before reperfusion. The results were evaluated as tissue neutrophil counts, tissue malondialdehyde content, tissue myeloperoxidase activity, and flap survival. Neutrophil counts and tissue myeloperoxidase activity were decreased significantly (p <0.001) in subgroup III, but lipid peroxidation by means of tissue malondialdehyde content was not affected by Fucoidin administration. The authors conclude that administration of Fucoidin before reperfusion can limit tissue injury apparently by inhibiting neutrophil rolling in a dose-dependent manner.

Effects of rolling inhibition on smoke inhalation injury

Inhalation of chemical and particulate products of smoke is one of the principal determinant of mortality following burn injury. Inflammatory responses have been implicated in the pathogenesis of lung injury after smoke inhalation. In the current study, we tested the inhibitory effect of Fucoidin on the neutrophil rolling stage of inflammatory response and determined the degree of pulmonary injury. Fifteen rats were divided into three groups: sham group (N: 5) of rats inhaled room air; control group (N: 5) inhaled smoke, and experimental group inhaled smoke and received Fucoidin. All the rats were sacrificed 24h after smoke inhalation. The trachea and lungs were removed totally; samples for histopathological and biochemical (myeloperoxidase (MPO)) analysis were taken from each lung and trachea. Morphologic studies using light and electron microscopes showed a decrease in lung parenchymal and tracheoepithelial injury in the experiment group of rats. Also, biochemical analysis of tissue MPO was significantly lower in test group than in control group. These results suggest that the inhibition of neutrophil rolling leads to a reduction of neutrophil invasion to pulmonary parenchyma and trachea, which may be beneficial for attenuating neutrophil mediated inhalation injury.

Effects of ischemic preconditioning protocols on skeletal muscle ischemia-reperfusion injury.

BACKGROUND Ischemic preconditioning (IPC) is described as brief ischemia-reperfusion (I/R) cycles to induce tolerance to subsequent in response to longer I/R insults. Various IPC protocols can be performed in four combinations as follows: at early or late phases and on local or distant organs. Although many experimental studies have been performed on IPC, no consensus has been established on which IPC protocol is most effective. The aims of the present study were as follows: (1) to compare the variables of preconditioning in different combinations (in early versus late phases; local versus remote organ implementations) and (2) to determine the most therapeutic IPC protocol(s). MATERIALS AND METHODS A subtotal hind limb amputation model with clamping an intact femoral pedicle was used for I/R injury. IPC was induced using hind limb tourniquet with 3 × 10 min I/R cycles before longer I/R insult. Forty-nine rats were divided into seven groups (n = 7), sham, IsO (ischemia only), I/R, early ischemic preconditioning (e-IPC), late ischemic preconditioning (l-IPC), early remote ischemic preconditioning (e-RIPC), and l-RIPC (late-remote) groups, respectively. In the sham group, pedicle occlusion was not performed. Six hours ischemia was challenged in the IsO group. Three hours ischemia followed by 3 h reperfusion was performed in the I/R group. The e-IPC group was immediately preconditioned, whereas the l-IPC group was preconditioned 24 h before I/R injury on the same hind limb. In the e-RIPC and l-RIPC groups, the same protocols were performed on the contralateral hind limb. At the end of the experiments, skeletal muscle tissue samples were obtained for biochemical analysis (Malondialdehyde [MDA], catalase, myeloperoxidase [MPO], and nitric oxide end products [NOx]), light microscopy, and caspase-3 immunohistochemistry for determination of apoptosis. RESULTS Tissue biochemical markers were improved in nearly all the IPC groups compared with IsO and I/R groups (P < 0.05). Similarly, the histologic damage scores were decreased in all the IPC groups (P < 0.05). The lowest damage score was in the e-RIPC group followed by the l-RIPC, e-IPC, and l-IPC groups, respectively. The apoptosis scores were significantly high in the I/R group compared with the e-RIPC and l-RIPC groups (P < 0.05). Although apoptosis scores of the e-IPC and l-IPC groups were lower than the I/R group, this finding was not statistically significant (P > 0.05). CONCLUSIONS All IPC protocols were effective in reducing I/R injury. Among these protocols, e-RIPC achieved most protection.

Do local anesthetics have antibacterial effect on Staphylococcus aureus under in vivo conditions? An experimental study.

OBJECTIVE The antimicrobial properties against Staphylococcus aureus of some common local anesthetic preparations such as prilocaine, bupivacaine, articaine, and combinations were evaluated in a live rat surgical wound model. METHODS This study was conducted at the animal research laboratory of Eskisehir Osmangazi University in 2003. Clean surgical wounds were created after local anesthetic application and inoculated with S. aureus (102 colony forming units/mL). Four days later, tissue cultures were harvested from control animals and animals given local anesthetic to determine the quantity of bacteria. RESULTS The tissue cultures demonstrated that none of the local anesthetics used in the study showed any inhibitory or bactericidal activity on S. aureus. There was no statistical difference in bacterial count between the local anesthetic–treated and control group wounds. CONCLUSION The results of the present study did not show any antimicrobial activity of above‐mentioned local anesthetics in surgically created wounds of rats. The authors have indicated no significant interest with commercial supporters.

Neuroprotective Effect of Genistein In Peripheral Nerve Injury.

AIM To investigate the effects of genistein in a rat model of sciatic nerve crush injury and complete sciatic nerve transection. The effects of genistein were compared with those of gabapentin, which is widely used in clinical practice for peripheral nerve injury. MATERIAL AND METHODS Forty-eight rats were randomly divided into six groups (8 rats in each group): group 1 (sham); group 2, sciatic nerve crush injury (control); group 3, sciatic nerve crush injury+genistein 20 mg/kg; group 4, sciatic nerve crush injury+gabapentin 90 mg/kg; group 5, sciatic nerve transection+genistein 20 mg/kg; group 6, sciatic nerve transection+gabapentin 90 mg/kg. The effects of genistein and gabapentin were assessed with immunohistochemical staining for growth associated protein-43 (GAP-43) and myelin basic protein (MBP). Interleukin-1β and tumor necrosis factor α levels in the injured nerve specimens were assessed as a measure of inflammatory response; walking track analysis and sciatic function index for neurological recovery and the paw mechanical withdrawal threshold were examined for neuropathic pain. RESULTS On histopathological examination, genistein use was associated with a greater immunoreactivity for GAP-43 and MBP compared with that associated with gabapentin. Genistein and gabapentin had similar effects on anti-inflammatory activity, functional recovery, and neuropathic pain. CONCLUSION Genistein and gabapentin exhibit positive effects on histopathology, inflammation, and clinical findings of peripheral nerve injury. When the systemic side effects of gabapentin are considered, genistein (a basic soy isoflavone that has no side effects) can be used as an alternative to medical treatment in peripheral nerve injury.

LYOPHILISED POLYURETHANE MEMBRANE DRESSING FOR SURGICALLY-SEPARATED PSEUDOSYNDACTYLY IN EPIDERMOLYSIS BULLOSA

The results of paraffin gauze dressing and lyophilised polyurethane membrane dressing were studied in a patient with surgically-separated pseudosyndactyly of dystrophic epidermolysis bullosa. Polyurethane membrane dressing decreased the time to epithelialisation and the need for anaesthesia.

Freestyle Perforator-Based Fasciocutaneous Flap Reconstruction in Nicolau Syndrome-Related Tissue Necrosis.

The actual pathology of the Nicolau syndrome (NS) is still unknown. It is thought to involve direct vascular damage and vasospasm. Many NS cases were reported in the literature but a treatment protocol is still not established. However, after demarcation of the necrotic tissue, surgical intervention is mandatory. Five NS cases with extensive tissue necrosis on the upper lateral gluteal region were analyzed retrospectively. Operative technique was described in details for freestyle perforator-based fasciocutaneous flaps from the gluteal region to reconstruct defects of NS-related tissue necrosis. Freestyle perforator-based fasciocutaneous flaps were used for defect closure in all patients. All flaps survived totally. No complications occurred during the follow-up period. Although rare, NS is a serious complication of inadvertent intramuscular injections. Prevention is the best treatment. However, in case of large-tissue necrosis, freestyle perforator-based fasciocutaneous flaps harvested from the gluteal region is a satisfactory option for reconstruction.

Can a Small Intestine Segment Be an Alternative Biological Conduit for Peripheral Nerve Regeneration

Background: Autologous nerve grafts are used to bridge peripheral nerve defects. Limited sources and donor site morbidity are the major problems with peripheral nerve grafts. Although various types of autologous grafts such as arteries, veins and muscles have been recommended, an ideal conduit has not yet been described. Aims: To investigate the effectiveness of a small intestinal conduit for peripheral nerve defects. Study Design: Animal experimentation. Methods: Twenty-one rats were divided into three groups (n=7). Following anaesthesia, sciatic nerve exploration was performed in the Sham group. The 10 mm nerve gap was bridged with a 15 mm ileal segment in the small intestinal conduit group and the defect was replaced with orthotopic nerve in autologous nerve graft group. The functional recovery was tested monthly by walking-track analysis and the sciatic functional index. Histological evaluation was performed on the 12th week. Results: Sciatic functional index tests are better in autologous nerve graft group (-55.09±6.35); however, during follow-up, progress in sciatic functional index was demonstrated, along with axonal regeneration and innervation of target muscles in the small intestinal conduit group (-76.36±12.08) (p<0.05). In histologic sections, distinctive sciatic nerve regeneration was examined in the small intestinal conduit group. The expression of S-100 and neurofilament was observed in small intestinal conduit group but was less organised than in the autologous nerve graft group. Although the counted number (7459.79±1833.50 vs. 4226.51±1063.06 mm2), measured diameter [2.19 (2.15-2.88) vs. 1.74 (1.50-2.09) µm] and myelin sheath thickness [1.18 (1.09-1.44) vs. 0.66 (0.40-1.07) µm] of axons is significantly high in the middle sections of autologous nerve graft compared to the small intestinal conduit group, respectively (p<0.05), the peripheral nerve regeneration was also observed in the small intestinal conduit group. Conclusion: Small intestinal conduit should not be considered as an alternative to autologous nerve grafts in its current form; however, the results are promising. Even though the results are no better than autologous nerve grafts, with additional procedures, it might be a good alternative due to harvesting abundant sources without donor site morbidity.

NERVE TİSSUE PREFABRİCATİON İNSİDE THE RAT FEMORAL BONE: DOES İT WORK?

AIM To investigate whether nerve regeneration can be induced in the tubular bone between distal and proximal cut nerve ends. MATERIAL AND METHODS Twenty adult Wistar rats were used for the study. Rats were divided into three groups; femoral bone conduit group, nerve transection group, sham group. The sciatic nerve was surgically cut and from both ends inserted into the adjacent femoral bone tunnel in the femoral bone conduit group. The sciatic nerve was cut transversely in the nerve transection group. In the Sham group, only sciatic nerve exploration was performed, without a nerve cut. The groups were evaluated functionally and morphologically. RESULTS All results showed that axonal growth existed through the osseous canal. CONCLUSION To the best of our knowledge, this is the first study to evaluate neural regeneration inside the bone. We can speculate that the bone marrow provides a convenient microenvironment for peripheral nerve regeneration. In addition to prefabricating peripheral nerves, this novel model may help to establish further strategies for engineering of other tissues in the bone marrow.