Browsing by Author "Cezayirli E."
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Item Ischemic preconditioning - Association of reperfusion and brain damage with metabolic state; [İskemik ön tanitim-reperfüzyon ve beyin hasarinin metabolik durumu ile ilişkisi](2005) Tuǧlu I.; Vural K.; Cezayirli E.; Varol T.; Özbilgin K.Stroke and cardiac arrest, which are major causes of death and disability, affect millions of individuals around the world and are responsible for the leading health care costs of all diseases. The ischemia-induced neuronal death is an energy dependent process and is the result of activation of cascades of detrimental biochemical and histological events that include perturbion of calcium homeostasis leading to increased excitotoxicity, malfunction of endoplasmic reticulum and mitochondria, elevation of oxidative stress causing DNA damage, alteration in proapoptotic gene expression, and activation of the effector caspases and endonucleases leading to the final degradation of the genome. Ischemic preconditioning of the brain describes the neuroprotection induced by a short, conditioning ischemic episode to a subsequent severe ischemic episode. The tolerance of the brain to an ischemic injury depends not only on the duration and severity of insufficient blood flow but also on various pre- and post-ischemic factors that are able to influence the post ischemic outcome. Recent experimental studies focus on the preischemic factors, that can increase the ischemic tolerance, among which the suppression of metabolic rate, the increase of brain tissue energy reserves and the inhibition of membrane permeability of cations are of particular importance. During the induction phase, aspartate and adenosine receptors, and oxygen free radicals and conservation of energy metabolism are required. Protein kinases, transcription factors, and immediate early genes appear to transduce the signal into a tolerant response. The brain succumbs to ischemic injury as a result of loss of metabolic stores, excessive intracellular calcium accumulation, oxidative stress, and potentiation of the inflammatory response. Neurons can also die via necrotic or apoptotic mechanisms, depending on the nature and severity of the insult. While it has been widely held that ischemia is notable for cessation of protein synthesis, brain regions with marginal reduction in blood supply are especially capable of expressing a variety of genes, the functions of many of which are only beginning to be understood. Gene expression is also upregulated upon reperfusion and reoxygenation. Brain extracellular levels of glutamate, aspartate, GABA and glycine increase rapidly following the onset of ischemia, remain at an elevated level during the ischemia, and then decline following reperfusion. In the early stages neuronal responses to ischem ia are dependent on the modulation of ion channels. Reactive oxygen species generated during ische-mia-reperfusion contribute to the injury. Oxygen free-radicals serve as important signalling molecules that trigger inflammation and apoptosis. The use of appropriate animal models is essential to predict the value and effect of therapeutic approaches in human subjects. Animal models should be used to determine dosage and duration of therapy, which will vary with the pharmacokinetic properties of different agents. Finally, physiological monitoring for the metabolic condition such as cerebral blood flow, blood pressure and gazes, body temperature, glycemia, etc., should be performed to eliminate confounding variables and to observe adverse systemic effects. Therefore, it is very important to know the experimental process, survey of animals, neurologic scoring, histological methods which highly affect the explanation of the results. In this review, we discuss mechanisms of ischemic brain damage and reperfusion related to metabolic condition and histology.Item Cell division and cellular morphology of the chick retinal pigmented epithelial cells in culture. A time-lapse analysis(2005) Tuglu I.; Cezayirli E.; Vural K.; Gungor K.; Varol T.; Bekir N.Objective: To investigate the patterns of cell division, movement and shape during early stages of development of the chick embryo retinal pigmented epithelial (RPE) cells and to evaluate the morphology of dissociated embryonic cells with regard to their proliferation capacity. Methods: We conducted this study at the Department of Histology and Embryology, Celal Bayar University, Manisa, Turkey, between 2002 and 2003. We isolated the cells from chick embryos. We analyzed the images of the embryonic cells originated from neuroepithelia using a computer-based time-lapse acquisition system attached to a differential interference contrast microscope. Results: Retinal pigmented epithelial cells, despite being dissociated, depict a colony-type growth. Cells in the periphery of the colony and those outside the colony showed a tendency to proliferate and migrate and retained contact with the neighboring cells during division. Characteristics of cytokinesis were separation from the neighboring cell while retaining an attachment point, became rounded, moved up and started to shake and ascend to disseminate to the substrate to complete the division. The round-up stage was non-significantly shorter when the cell was closer to the center of the colony. Cells that were in the periphery of, or outside the colony had a round-up time of over one hour while cytokinesis-to-adhesion time was around 5 minutes. However, when we found the cells in the center of the colony, the times were half-an-hour and 1.5 hours for the daughter cells, a 2-fold difference between daughter cells with regard to the duration of attachment. Conclusion: Cell division, migration and proliferation are complex procedures influenced by growth factors, cell adhesion, matrix molecules underneath and the signal mechanisms and can be studied in detail using time-lapse microscopy, immunohistochemistry and confocal microscopy.Item Comparative morphometry of the lower lumbar vertebrae: Osteometry in dry bones and computed tomography images of patients wtih and without low back pain(SAGE Publications Ltd, 2006) Varol T.; Iyem C.; Cezayirli E.; Erturk M.; Kayalioglu G.; Hayretdag C.Various factors affect the development of the vertebral canal. The dimensions of the vertebral canal and the intervertebral foramen can be altered by these factors before or after birth. Sex differences in dimensions have also been reported. When there is a stenosis of the vertebral canal or the intervertebral foramen, neural structures confined within them can be affected easily, resulting in symptoms. Using computed tomography images, we compared vertebral canal dimensions in 100 patients with low back pain and/or radiculopathy with those in 40 healthy, non-symptomatic controls. We also measured the dimensions of 275 dry bones. We found significant correlations among the variables in the live subjects. We found significant differences between patients and controls in the variables that were measured. Stenoses were more prevalent in females. Dry bone measurements showed some sex differences, and stenosis mainly in vertebrae L4, L5 and S1. Copyright © 2006 Cambridge Medical Publications.Item Effects of sex and age on regional prefrontal brain volume in two human cohorts(2007) Cowell P.E.; Sluming V.A.; Wilkinson I.D.; Cezayirli E.; Romanowski C.A.J.; Webb J.A.; Keller S.S.; Mayes A.; Roberts N.This study examined interactive effects of sex and age on prefrontal brain anatomy in humans. It specifically targeted ranges of the adult life span and regions of cortex that previously showed male-female differences. Participants were 68 healthy human males and females aged 20-72 years. Data collection and analysis were conducted in parallel across two cohorts (laboratories) to investigate reproducibility of effects in relation to sex and age. Volumes for four regional prefrontal subfields per hemisphere were obtained from high-resolution MRI. Regional sex by age interactions were replicated across cohorts. In men, age effects were greatest in medial prefrontal volume, with decreases in dorsal medial and orbital medial regions. In women, age-related changes in medial prefrontal regions were limited to the dorsal volume, with additional decreases observed in lateral subfields. Cohort and Cohort x Age effects in total brain and total prefrontal volume were linked to a combination of methodological and sampling-related factors. Findings indicated that neuroanatomical changes throughout adulthood unfold along different time scales in men and women. Results also showed that sex differences in ageing localized to medial prefrontal regions were particularly robust to variation across cohorts. © The Authors (2007).Item Morphometry of the cervical vertebral pedicles as a guide for transpedicular screw fixation(2007) Kayalioglu G.; Erturk M.; Varol T.; Cezayirli E.Anatomical measurements of the cervical pedicle in a large series of human cervical vertebrae from 48 individuals were obtained to reduce the incidence and severity of complications caused by transpedicular screw placement. The greatest pedicle length was at C-3 and the greatest pedicle width was at C-6. Pedicle width and lateral mass thickness gradually increased from C-3 to C-6. Pedicle height and interpedicular distance increased from C-3 to C-5, and decreased slightly at C-6. The lateral mass-pedicle length was greatest at C-4. The present study found right-left differences for the pedicle-spinous process distance at C-6 (p < 0.05). Pedicle width and height were smaller than those reported in earlier studies, especially at C-3 and C-4, whereas the increasing pedicle widths at C-5 and C-6 were appropriate for pedicle screw fixation.Item In vitro effects of culture medium and serum on germ cells in testis and epididymis of male wistar rats; [Erkek wistar ratlarda kültür medyumunun ve serumun testis ve epididimis germinal hücreleri üzerine in-vitro etkileri](2009) Cezayirli E.; Tuǧlu M.I.; Vural K.; Varol T.The present study was designed to examine the influence of culture media and serum on survival of in vitro rat sperms. The effects of different culture media with or without 10% fetal bovine serum (FBS) on spermatids and spermiums of Wistar rats were assessed in vitro between 2004 and 2005. Spermatozoa were cultured in Gamete-20, RPMI-1640, alphaMEM (AMEM), Dulbecco's modified Eagle's medium (DMEM) and Eagle's MEM (MEM). The number and morphology of cells was recorded at 4 and 24 h. Under all conditions the number and the viability of the cells decreased with time but parameters were positively affected by the presence of FBS. Viability rates of spermatids and spermatozoa reduced at 24 h of culturing. The survival and morphology were the best in RPMI with serum and worst in MEM without serum. These results indicate that different composition of culture media and FBS are important for maturation and survival of spermatozoa. Carefully selected culture media can play important roles in the generation of functional sperms as well as in the success of in-vitro fertilization (IVF) procedures.Item Comparison of blood brain barrier permeability in normal and ovariectomized female rats that demonstrate right or left paw preference(2012) Kutlu N.; Mutlu F.; Vural K.; Cezayirli E.We explored the relations among paw preference, cerebral asymmetry and asymmetrical disruption of blood-brain barrier (BBB) permeability in normal and ovariectomized female rats with known paw preference. A high dose of pentylenetetrazol was used to disrupt the BBB and induce acute hypertension. To determine the areas of macroscopic infarct, samples were stained with 2,3,5-triphenyltetrazolium chloride. Histological staining techniques were used to show the areas of infarct microscopically on paraffin sections. Sixty-two percent of the rats demonstrated right paw preference, 24% demonstrated left paw preference and 14% were ambidextrous. Areas of infarct, which indicated destruction of the BBB, were determined microscopically and macroscopically in rats that demonstrated right and left paw preference. We found a relation between permeability of the BBB and paw preference. There may be a relation between paw preference, cerebral asymmetry and asymmetrical destruction of the BBB in rats. Asymmetrical destruction of the BBB in experimental rats was similar to the control group, which had asymmetrically disrupted BBB with respect to paw preference. Like the control rats, asymmetrical areas of infarct consistent with cerebral asymmetry were observed in ovariectomized rats. © 2012 The Biological Stain Commission.