Mehmet Kaya

Effect of magnesium, MK-801 and combination of magnesium and MK-801 on blood–brain barrier permeability and brain edema after experimental traumatic diffuse brain injury

Abstract Objective: Glutamate antagonists are very attractive drugs in laboratory works to protect neural tissue against ischemia. In this work, the effects of magnesium, MK-801 and combination of magnesium and MK-801 on blood–brain barrier (BBB) and brain edema after experimentally induced traumatic brain injury are evaluated. Methods: A standard closed head injury was induced on the rats by a controlled impact device using a 450-g free falling mass from a height of 2 m onto a metallic disc fixed to the intact skull. One of the following was injected to animals intraperitoneally 30 minutes after injury: saline, magnesium, MK-801 and magnesium plus MK-801. To quantify the brain edema, the specific gravity of the brain tissue was determined. To demonstrate the alteration of the BBB permeability, Evans blue dye was used as a tracer. Results: In all treatment groups, the specific gravity of brain tissue values was significantly higher compared with the control group. Evans blue dye content in the brain tissue was significantly reduced in all three treatment groups with respect to the control group. There was no significant difference of effect between the groups of magnesium alone and MK-801 alone when compared with each other and when compared with their combination. Conclusion: The present data demonstrate that treatment with magnesium, MK-801 and combination of magnesium and MK-801 can reduce formation of brain edema and can help restore BBB permeability after experimental diffuse brain injury.

Effects of trapidil on ATPase, lipid peroxidation, and correlation with ultrastructure in experimental spinal cord injury

Abstract The present study was performed to investigate the effect of trapidil on ischemic damage of cells after spinal cord injury. The injury was produced by extradural clip compression of the exposed spinal cord in rats according to Rivlin and Tator. The ten rats in group 1 were used to determine normal findings without any surgery or medication. On the 15 rats in group 2, only six-level laminectomy was performed to determine the influence of the total laminectomy on the biochemical factors measured and the light and ultrastructural findings. The 15 rats each in groups 3 and 4 were used as trauma and trapidil (40 mg/kg) treatment groups, respectively. The injury actually produced a significant decrease in Na+–K+/Mg+2 ATPase activity of the injured segments as early as 10 min after trauma. Trapidil attenuated Na+–K+/Mg+2 ATPase inactivation in the traumatized rats for 120 min after treatment (P<0.05) and significantly reduced the malone dialdehyde content below that in the traumatized group at all determined times (P<0.05). Light and electron microscopic findings supported the biochemical results.

Correlation of alterations on Na+-K+/Mg+2 ATPase activity, lipid peroxidation and ultrastructural findings following experimental spinal cord injury with and without intravenous methylprednisolone treatment

The sodium-potassium activated and magnesium dependent adenosine-5′-triphosphatase (Na+−K+/Mg+2 ATPase EC 3.6.1.3.) activity and lipid peroxidation and early ultrastructural findings are determined in rat spinal cord at the early stage of trauma produced by a surgical clip on the thoracal 2–7 segments. The effect of treatment with intravenous methylprednisolone (MP) was evaluated the basis of these biochemical alterations and ultrastructural findings in the same model. The specific activity of the membrane bound enzyme Na+−K+/Mg+2 ATPase was promptly reduced in as early as ten minutes following spinal cord injury and remained at a level lower than the levels in the control group and in the sham-operated group. Methylprednisolone treatment immediately after the trauma attenuated the inactivation of Na+−K+/Mg+2 ATPase. On the other hand, there was significant difference in lipid peroxide content between the sham-operated and the injured animals. Methylprednisolone treatment reduced thiobarbituric acid reactive substance (TBARS) content in Group IV. We determined a positive relationship among membrane-bound enzyme Na+ K+/Mg+2 ATPase activity, malondialdehyde (MDA) content and early ultrastructural changes in the traumatized and treated groups.These data provide evidence for a beneficial effect of methylprednisolone on the activation of Na+−K+/Mg+2 ATPase and lipid peroxidation and early ultrastructural changes in spinal cord injured rats. The possible mechanism of methylprednisolone effects on the membrane function and lipid peroxidation, and the correlation of biochemical changes with ultrastructural findings are briefly discussed.

Adenoids and otitis media with effusion : A morphological study

PURPOSE Adenoidectomy, especially for the treatment of suppurative otitis media, has been used for a very long time. In this study, the role of adenoids in the origin of otitis media with effusion was investigated by using light microscopy, immunocytochemistry, enzyme chemistry, and electron microscopy. MATERIALS AND METHODS A group of 28 children with otitis media with effusion (OME) was identified. Ages ranged from 3 to 12 years. A control group of 10 age-matched children without any middle ear and upper respiratory tract infection served as the basis for comparison. Specimens obtained at surgeries from both groups were divided into groups for light microscopy, immunocytochemistry, enzyme cytochemistry, and electron microscopy and then all were examined blindly. Also, quantitative analysis of antigen-presenting cells was performed blindly on 10 patients and 10 controls. RESULTS There was an increase in the number of lymphocytes, mast cells, plasma cells, macrophages, dendritic cells, and M cells in the adenoids of patients with OME when compared with the normal cases. Stratified squamous epithelial areas, collagenous fibers, and fibrocytes were also increased in the patient group. Antigen-presenting functions of epithelial cells are shown by major histocompatibility complex (MHC) class II positivity of some ciliated-columnar epithelial cells in the patient group. CONCLUSION Adenoid tissues of patients with OME in this study seem to be infectious foci, aggravating immune reactions, which might attack the middle ear through an ascending route.

Changes of Middle Ear Mucosa in Secretory Otitis Media Treated with Ventilation Tubes

The present study was designed to obtain the precise ultrastructural status of the middle ear mucosa of patients to whom ventilation tubes were applied for the treatment of secretory otitis media (SOM). This study comprised 14 children with SOM aged 5-11. Normal epithelium obtained from otosclerotic patients as controls was composed of three main cell types; basal, ciliated, and secretory. Electron microscopic observations revealed that ciliated cells were almost completely absent in the epithelium of patients with SOM. Secretory cells, on the other hand, were noted to be increased in number with cytoplasmic features indicating active secretory phase; abundant secretory granules in these cells featured both serous and mucoid characteristics. Following the application of ventilation tubes, the micrographs exhibited a vast number of ciliated cells. Furthermore, the secretory cells were less conspicuous and the secretory granules were mostly serous in type. The ultrastructural findings of this investigation strongly suggest that the application of ventilation tubes in cases of SOM stimulates ciliated cell regeneration, inhibits secretion of mucoid material, and activates serous secretion; all of which eventually shorten the recovery period.

The effects of the pretreatment of intravenous high dose methylprednisolone on Na(+)-K(+)/Mg(+2) ATPase and lipid peroxidation and early ultrastructural findings following middle cerebral artery occlusion in the rat.

SummaryThe sodium-potassium activated and magnesium dependent adenosine-5′-triphosphatase (Na+-K+/Mg+2 ATPase EC.3.6.1.3.) activity and lipid peroxidation and early ultrastructural findings were determined in rat brain at the acute stage of ischaemia produced by permanent unilateral occlusion of the middle cerebral artery (MCA). The effects of the pretreatment with intravenous high-dose methylprednisolone (MP) on these biochemical indices and ultrastructural findings were also evaluated in the same model. The rats were divided into four groups. In group I, 10 rats were used to determine Na+-K+/Mg+2 ATPase activity and the extent of lipid peroxidation by measuring the malondialdehyde (MDA) content and normal ultrastructural findings. In group II on 20 rats, only subtemporal craniectomy was done in order to determine the effects of the surgical procedure on these indices and findings. This group was treated intravenously with saline solution before occlusion. In group III with MCA occlusion, saline solution was administered intravenously to 20 rats in the same amount of methylprednisolone used in group IV, ten minutes before the occlusion. In Group IV, a single high-dose (30 mg/kg) of methylprednisolone was administered intravenously, ten minutes before occlusion in 20 rats. After occlusion of the middle cerebral artery, Na+-K+/Mg+2 ATPase activity was decreased promptly in the first ten minutes in the ischaemic hemisphere and remained at a lower level than the contralateral hemispheres in the same group and the normal levels in group I, during 120 minutes of ischaemia. A single dose methylprednisolone pretreatment prohibited the inactivation of Na+-K+/Mg+2 ATPase. On the other hand, there was significant difference in malondialdehyde content between group I and group III. Malondialdehyde levels were significantly increased following ischaemia and a non-significant increase was observed in the contralateral hemisphere. Methylprednisolone treatment significantly decreased malondialdehyde content on the side of the ischaemic hemisphere. We conclude that there is a positive relationship between membrane-bound enzyme Na+-K+/Mg+2 ATPase activity, malondialdehyde content and early ultrastructural changes in the treated group with MP.These data suggest that the pretreatment injection of high doses (30 mg/kg) methylprednisolone contribute to the protection of the brain from ischaemia with stabilization of the cell membrane by effecting the lipid peroxidation and the activation of Na+-K+/Mg+2 ATPase.

Moloney Darn Repair Versus Lichtenstein Mesh Hernioplasty for Open Inguinal Hernia Repair

PurposeTo compare two tension-free techniques of inguinal hernia repair: the Moloney darn repair (MDR) and Lichtenstein mesh hernioplasty (LMH).MethodsThe subjects of this study were 651 patients from a total 732 who underwent open inguinal herniorrhaphy at our clinic between January 2000 and January 2006. We evaluated and compared analgesic requirement in the first 24 h, operative time, hospital stay, early postoperative complications, time until return to work, and recurrence, between patients who underwent MDR (group A) and patients who underwent LMH (group B).ResultsGroup B patients required less analgesia in the first 24 h than group A patients. Conversely, the mean operative time and postoperative hospital stay were shorter in group A. Early postoperative complication rates and the time until return to work did not differ significantly between the two groups. During follow-up, recurrences developed in three patients from group A and four from group B. The cost of MDR was significantly less than that of LMH.ConclusionsBoth MDR and LMH resulted in rapid recovery and low recurrence rates; however, the advantage of the MDR lies in the fact that it does not require mesh, so it is much less expensive.

Effect of prostacyclin and adenosine triphosphate on vasospasm of canine basilar artery

Cerebral vasospasm is one of the most important factors influencing morbidity and mortality of intracranial operations or diseases. Platelet aggregation and adhesion is increased in spastic vessels. Degradation of platelets liberates mediators, which in turn increase vasospasm, thus creating a vicious cycle. Healthy vessels cope with this by increasing the synthesis of prostacyclin. The purpose of this study was to increase experimentally the levels of arterial prostacyclin and adenosine triphosphate (ATP) in animals through intraarterial injection of these substances because they are lower in spastic vessels. Prostacyclin promotes antiaggregation and dilatation, increases blood flow, inhibits thromboxane A2, and prevents synthesis of angiotensin II. Most of these effects were done by increasing cyclic adenosine monophosphate (cAMP). After injecting autogenous blood into the cisterna magna of male dogs, both the acute and chronic phases of vasospasm and the degenerative changes in the arterial wall were observed. Injecting ATP increased the severity of vasospasm. During vasospasm it was found that when prostacyclin is used intraarterially, vasodilatation began, but degeneration of the arterial wall could not be prevented. In the group of animals in which both ATP and prostacyclin were used, there was no degeneration of the arterial wall and the basilar artery was seen to be normal when viewed under the electron microscope.

Experimental evaluation of peritoneum and pericardium as dural substitutes

Although many substances have been tested in the search for an ideal dural substitute, an entirely satisfactory material has still not been found. The authors report an experimental study involving the closure of dural defects in rabbits with biomaterials developed from pig peritoneum and pericardium. Macroscopic and histologic examination, performed over a period between 15 and 45 days after implantation showed slight or no adhesion between the graft material and the cortex. No infection, CSF leakage, fistula or toxicity was noticed. The results demonstrated that these biomaterials could be used as satisfactory dural substitutes.

Effects of Methotrexate on the Tubal Morphology of Rabbits: Evaluation by Electron Microscopy

Background/Aims: To evaluate by electron microscopy the effects of methotrexate on the tubal morphology of rabbits. Methods: Biopsies were taken from the isthmic portion of both tubes of 4 rabbits in the control group. 1 mg/kg methotrexate was injected in the left tubes and as a control, a 14-gauge fine needle was used to puncture the right tubes of 10 rabbits in the study group. One month later, tubal biopsies were taken from both tubes of every rabbit in the study group. To mimic pregnancy, 100 IU hCG was injected intramuscularly to every rabbit 24 h before every surgery. On examination by electron microscopy, the effects of methotrexate and of the damage with the fine needle on the tubes were compared to the control group. Results: Young epithelial cells of the methotrexate-injected fallopian tubes kept their normal structure, but others contained important ultrastructural changes. These were: nuclear pyknosis, cytoplasmic vacuolization, dilatation of endoplasmic reticulum cisternae, increased cytoplasmic density and compound cilia. Conclusion: Degenerative changes on epithelial cells caused by the temporary blockage of mitotic activity associated with local methotrexate injection are reversible through the formation of new epithelial cells.