MCBÜ Açıkerişim Sistemi :: Browsing by Author "Varol T."

Browsing by Author "Varol T."

Now showing 1 - 13 of 13

The effect of gravity on the living organisms; [Yerçekimi deǧişikliklerinin canlilar üzerine etkileri: Mikroyerçekiminde ne ofmaktadir?]
(2000) Varol T.
The terrestrial animals are continuously under the effect of gravity. Gravity plays a role as an environmental factor, which determinates the process of intrauterine and postnatal development starting from fertilisation to every stage of life. The effect of gravity on the living organisms has become more important since space travelling with human and the possibility of colonisation in the space. There is great research on the effect of microgravity as an altered environmental factor in the space and in the planet which has smaller mass than earth. The progressive decreased bone mass occurs in the microgravity environment. This space osteoporosis which is similar to postmenopausal osteoporosis associates especially in the sponges part of weight bearing bones. It has been explained by the sensitivity of the osteoblast against the gravity and has been shown by the studies, which the number and the function of these cells were decreased in the microgravity environment. Rapid skeletal muscle atrophy and decrease of the neuronal activation in the CNS can be seen in the microgravity environment. There is also clear decrease of the number of T lymphocyte in microgravity conditions but it has not yet shown that this is a dangerous risk for human health. Other clinical symptoms like moderate hypothyroidism, decrease of insulin sensitivity, anaemia due to decrease of the erithropoietin levels in this conditions are still remains unclear, however, it seems that they are originated from the decrease of mobility and the decrease of energy requirement. In contrast, there is increase of cathecholamine activity that seems parodoxal. The negative effect of microgravity on the fertilisation and embryogenesis has not been shown yet and it does not effect lactation and maternal behaviour. Microgravity results in changes in the vestibular otolith organs and in the processing of inputs from otolith receptors and in alterations in the gain of vestibular influences on cardiovascular control which may produce orthostatic hypotension. The results of studies in the simulation of microgravity in the world and/or in the space laboratory shows that locomotor system, vestibular system and endocrine system are more effected by the microgravity environment. Although, these studies are still far away from the clear answers of the scientific questions for this matter but the life in microgravity and the possibility of alternative treatment using microgravity are not impossible and not a dream.
Heights of the cerebral falx: Surgical and clinical implications
(2004) Kayalioglu G.; Erturk M.; Varol T.
Objectives: Variations in the shape and size of the cerebral falx can embarrass the surgical treatment of lesions in and around the falx. In this study, anatomy and morphometry of the cerebral falx in adult cadaveric specimens were examined to enable easy approach during sucgery. Methods: Fifty-two adult cadaver cerebral hemispheres with dura from the cadaver collection of the Department of Anatomy, Ege University, Faculty of Medicine were examined in 2003. The cerebral falx was observed in 3 different types. The heights of the cerebral falx and the heights of interspace between the lower margin of the cerebral falx and corpus callosum were measured. Results: The most frequently observed type of cerebral falx was Type I based on the classification of Jiang and Jia. The average heights of the cerebral falx measured 21.3 mm anteriorly, 25.7 mm in the middle and 45.6 mm posteriorly in Type I; 27.9 mm anteriorly, 30.5 mm in the middle and 47 mm posteriorly in Type II; 28.7 mm anteriorly, 36.5 mm in the middle and 44.1 mm posteriorly in Type III. The average heights of the interspace between the lower margin of the cerebral falx and corpus callosum were 14.1 mm anteriorly, 12.4 mm in the middle and 2.1 mm posteriorly in Type I; 6.3 mm anteriorly, 7.2 mm in the middle and 1 mm posteriorly in Type II; 2.3 mm anteriorly, 1.8 mm in the middle and 0.6 mm posteriorly in Type III. Natural defects were found on the cerebral falx in 12 (23%) specimens. Conclusion: Measurements of the cerebral falx provide useful information for neurosurgeons in treatment of lesions involving the region. This study presents more detailed data compared to those reported in the few previously published papers, results differing due to differences of the populations investigated.
The cranio-orbital foramen, the groove on the lateral wall of the human orbit, and the orbital branch of the middle meningeal artery
(2005) Erturk M.; Kayalioglu G.; Govsa F.; Varol T.; Ozgur T.
The cranio-orbital foramen, a foramen in the lateral wall of the orbit, contains an anastomosis between the anterior branch of the middle meningeal artery and the lacrimal artery. Previous workers have speculated that the groove starting either from the cranio-orbital foramen or the lateral extremity of the superior orbital fissure contains the anastomotic artery. We investigated the cranio-orbital foramen and the groove on the lateral wall of the orbit in a series of 170 dried adult human skulls, and the course of the orbital branch of the middle meningeal artery in 74 specimens from 37 cadavers. We observed the cranio-orbital foramen in 141 skulls (82.9%). It was unilateral in 55 (32.4%) and bilateral in 86 (50.6%) skulls. The groove on the lateral wall of the human orbit was observed in 122 skulls (71.8%). It was unilateral in 40 (23.5%) and bilateral in 82 (48.2%). The groove on the lateral wall of the orbit started from the cranio-orbital foramen in 20 skulls (11.8%). The orbital branch of the middle meningeal artery was found in 48 cadaveric specimens (64.9%): 32 (43.2%) passed through the cranio-orbital foramen and 12 (16.2%) passed through the superior orbital fissure. In four specimens (5.4%), orbital branches of the middle meningeal artery passed through both the superior orbital fissure and the cranio-orbital foramen. The anatomy of the cranio-orbital foramen and the course of the orbital branch should be well known by surgeons reconstructing the anterior base of the skull, the orbit after orbital base surgery, and during excision of meningiomas. © 2004 Wiley-Liss, Inc.
Variations in sphenoid sinus anatomy with special emphasis on pneumatization and endoscopic anatomic distances
(2005) Kayalioglu G.; Erturk M.; Varol T.
Objectives: The purpose of this study was to present the morphometry and pneumatization of the sphenoid sinus in detail for the neurosurgeon for transnasal approach to the hypophyseal tumors and especially for functional endoscopic sinus surgery. Methods: One hundred and eighty midsagittal magnetic resonance images, 48 bones and 29 hemi-sectioned cadaveric heads obtained from Ege University, Faculty of Medicine, Departments of Anatomy and Radiology were used in 2003. The sphenoid sinuses were classified into sellar, pre-sellar, conchal and post-sellar types according to the extent of their posterior limits. Different measurements based on the surgical approach and sinus size were performed. Results: Conchal type sinus was observed in 1.9%, pre-sellar type 9%, sellar type 52.9% and post-sellar type 36.2% of the specimens. Conchal type sphenoid sinus was not observed in males, but in 1.7% of females. Pre-sellar type was observed in 5.6% of males and 2.8% of females. Sellar type was found in 24.4% of males and 23.9% females, and post-sellar type in 19.5% of males and 22.2% of females. The sphenoid sinus length at the upper and lower parts was 13.51±3.25mm and 24.57±6.65mm. The sphenoid sinus height at the anterior and posterior parts was 21.27±4.25mm and 14.5±4.07mm. Distance from the ostium to limen was 56.6±5.6mm and from ostium to sill was 64.6±6.11mm in cadaveric specimens. In MR images, distance from the ostium to the sill was 68.7±5.9mm and from sella to sill 82.8±6.2mm. Conclusion: Sphenoid sinus variations observed in pneumatization, size, localization and shape are important in providing a better surgical approach and avoiding surgical complications.
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.
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.
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.
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.
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.
Assessment of lung toxicity caused by bleomycin and amiodarone by Tc-99m HMPAO lung scintigraphy in rats
(2013) Gumuser G.; Vural K.; Varol T.; Parlak Y.; Tuglu I.; Topal G.; Sayit E.
Aim: The purpose of the study was to determine the lung toxicity caused by amiodarone (AD) and bleomycin (BLM) in rats, by means of Tc-99m HMPAO lung scintigraphy. Methods: Thirty albino rats were randomly divided into five groups. After AD or BLM was dissolved with isotonic saline (SF), a 0.5 ml solution was applied to the right bronchus via a catheter. Group 1 (n = 5 rats) received a single dose of AD, group 2 (n = 5) received two doses of AD, group 3 (n = 9) received BLM, group 4 (n = 3) received hydrochloric acid (HCl), and group 5 (n = 8) received SF. Rats in groups 1, 2, 3 and 5 were given 37 MBq Tc-99m HMPAO from the tail vein on days 7, 14, 21 and 28, and at 4 and 24 h in group 4. Static images of 10 min duration were obtained at 30 and 60 min by a double-headed gamma camera (Infinia, GE, Tirat Hacermel, Israel) on 256 × 256 matrix. Regular regions of interests were drawn over the right lung (RL), left lung (LL) and the liver (Li), and lung/liver (L/Li) ratios were calculated. After the scintigraphic imaging procedures were completed, rats were killed. Lung tissues were evaluated on a scale of (+) to (+++++) for edema, alveolar structural integrity and infiltration by inflammatory cells. Results: Groups 2 and 3 showed statistically significant differences in RL/Li and LL/Li ratios, whereby RL/Li was higher than LL/Li (p < 0.05). There were no significant differences in RL/Li and LL/Li ratios in group 5 (p > 0.05). In histopathological examination, minimal damage or artifacts were observed in group 5. In group 4, almost all pathological findings were present in the right lung. Statistically significant (p < 0.01) histological differences were found when groups 1 and 5 were compared. More significant (p < 0.001) pathological effects were noted when groups 2 and 3 were compared to both groups 5 and 1. Injury was more prominent in the lung tissues of the control rats that were given HCl. Increased RL/Li ratios and histopathological findings were consistent. Conclusion: Tc-99m HMPAO lung scan are found to be useful in the identification of patients with lung toxicity. The simplicity of the procedure and lower radiation exposure are the advantages of Tc-99m HMPAO lung scan. © 2013 The Author(s).
Relation between foot pain and plantar pressure in pregnancy
(Turkiye Klinikleri Journal of Medical Sciences, 2017) Varol T.; Göker A.; Cezayırlı E.; Özgür S.; Tuç Yücel A.
Background/aim: Hormonal and structural changes that occur during pregnancy cause alterations in body biomechanics. These alterations reach their peak in the last trimester. Adaptive changes that appear in the foot result in pain in the foot and ankle. Pedobarography is a noninvasive measurement method that can be used to understand the origin of such pain. Materials and methods: One hundred and thirty-one pregnant women who did not have a foot or ankle problem prior to pregnancy volunteered to take part in the study. Pain was quantified by a visual analog scale (VAS). A cut-off value of 2.95 was taken to divide the subjects into two groups: Group 1 (n = 70) with VAS scores of <2.95 and Group 2 (n = 61) with VAS scores of ≥2.95. Plantar pressure measurements were taken by Tekscan HR Mat using midgait protocol. Results: Forces experienced by the total right foot area, right forefoot, and the midfoot for both feet were significantly higher in Group 2 (P < 0.05). Contact area was significantly larger in Group 2 (P < 0.05). Conclusion: Results indicate that presence and severity of foot pain during pregnancy are related to the force distribution along the foot, especially at midfoot and the contact area. © TÜBİTAK.
Anxiety sensitivity, stress, and postural control: their implications on archery performance in 11–14-year-olds
(Wroclaw University of Health and Sport Sciences, 2023) Tokmakci H.H.; Özgür S.; Varol T.
Purpose. Archery, a sport based on individual performance, requires postural stability, concentration and the ability to cope with stress. The effect of stress on success, however, is not clear in the adolescent age group. The present study investigates the association between stress and trait anxiety levels and postural control and shooting performance in young adolescent archers. Methods. Included in the study were a total of 22 licensed archers (6 female; 16 male) aged between 11 and 14 who were evaluated using the ‘Anxiety Sensitivity Index-3’ and ‘Trier Social Stress Test’ (child version, arithmetic component) to measure their trait anxiety status and susceptibility to stress, respectively. Stress was measured based on the number of heartbeats per minute. An evaluation of static postural control was made using a pedobarography device before arrow release, with and without subjecting the archer to stress. To assess performance, 10 arrows were shot at a target 18 metres away, twice – before and after subjecting the participant to stress.. Results. Postural control showed no significant change under stress. However, the participants’ trait anxiety status inversely correlated with shooting success. Post-stress shooting scores correlated with total ASI-3 score (r = –0.513; p = 0.021) and its social sub-group (r = –0.634; p = 0.003). Conclusions. A moderately inverse correlation can be noted between the trait anxiety state and shooting success in young adolescent archers subjected to stress. Furthermore, stress was observed to have a detrimental effect on the shooting success of people with a high level of trait anxiety. © Wroclaw University of Health and Sport Sciences.
Effects of Efflux Pump Inhibitors and Antileishmanial Drug Combinations on Leishmania tropica and Leishmania infantum Isolates; [Dışa Atım Pompa İnhibitörleri ve Antilayşmanyal İlaç Kombinasyonlarının Leishmania tropica ve Leishmania infantum İzolatlarına Etkisi]
(Ankara Microbiology Society, 2025) Yener Ö.; İbrahim Ç.; Varol T.; Tülay A.; Mehmet Ü.; Ahmet Ö.
Drug resistance, one of the most important public health problems facing humanity, necessitates new strategies and approaches in the development of antileishmanial agents. Although developments regarding efflux pump inhibitors (EPIs) and other candidate agents are promising, the search continues to increase the duration of use and efficacy of existing antileishmanials. The aim of this study was to investigate the antileishmanial effects of three EPIs, namely reserpine, berberine and verapamil. The antileishmanial activities of EPIs, pentostam and miltefosine against Leishmania tropica and Leishmania infantum strains were determined by broth microdilution method. Minimum parasiticidal concentration (MPC) values were determined by inverted microscope and IC50 values were determined by MTT viability assay method. The effects of EPIs with determined antileishmanial activities on miltefosine and pentostam were investigated by checkerboard method. The MPC values of antileishmanial drugs miltefosine and pentostam for L.tropica and L.infantum were determined as 64 and 196 µg/mL at 24 and 48 hours, respectively. The MPC values of EPIs reserpine and berberine were determined as 314 and 64 µg/mL for the same incubation times and for verapamil, they were determined as 80 µg/mL at 24 hours and 40 µg/mL at 48 hours. Among anti-leishmanials, the IC50 values of miltefosine were calculated as 4.91/3.47 and 4.05/2.91 µg/mL for L.tropica and L.infantum at 24 and 48 hours, respectively and that of pentostam were calculated as 34.58/59.86 and 18.48/40.63 µg/mL at the same incubation times, respectively.The IC50 values of EPIs, reserpine, berberine, and verapamil were calculated as 74.05/50.61, 7.27/6.1, and 12.52/4.53 µg/mL for L.tropica at 24/48 hours, respectively and 64.52/51.72, 8.21/8.01, and 11.59/7.69 µg/mL for L.infantum. When miltefosine was combined with reserpine, berberine or verapamil, synergistic interactions were observed at 24 and 48 hours of incubation. When pentostam was combined with reserpine, partial synergy was observed at 24 hours and synergy was observed at 48 hours. When pentostam was combined with berberine or verapamil, synergistic interactions were observed at both incubation conditions. Synergy results were found to be the same in both L.tropica and L.infantum strains. In recent years, the speed of research on the discovery of new antimicrobials has significantly decreased and it has become necessary to investigate new molecules that can affect resistance mechanisms. It is thought that EPIs may be a promising approach that can increase the clinical performance of antileishmanial agents and reduce the level of side effects in the fight against drug resistance. © 2025 Ankara Microbiology Society. All rights reserved.

Browsing by Author "Varol T."

Results Per Page

Sort Options