Özden Palaoğlu

The possible role of benzodiazepine receptors in morphine analgesia.

Diazepam within its therapeutic dose range, was shown to have no effect on nociception, but was shown to antagonize the analgesic action of morphine. This antagonism was found to be statistically significant at 0.5 mg/kg diazepam. To elucidate the mechanism of this inhibitory action of diazepam against morphine analgesia, Ro 15-1788, the specific antagonist of benzodiazepine receptors was used. As a result, Ro 15-1788 was found to partially reverse the inhibitory action of diazepam against morphine analgesia. This overall interaction between the supramolecular GABA receptor complex and morphine is discussed.

Perceptions of Students in Different Phases of Medical Education of Educational Environment: Ankara University Faculty of Medicine

Abstract The present study was undertaken to identify the perceptions of students about their educational environment in a newly restructured curriculum. The Turkish version of the DREEM questionnaire (total score: 200) was used to diagnose the strengths and weaknesses of the curriculum which is known to be a major determinant of educational environment. Five hundred fifty three students (years 1, 3, 5) voluntarily replied to the questionnaire. The mean DREEM score was found to be 117.63 (58.8%). The mean scores for the whole DREEM questionnaire and the five essential domains were found to be significantly different in different phases of medical education. The scores were found to be highest (123.65) for year 3 students and lowest (109.39) for year 5 students. The results are the first data of a curriculum reform obtained from the students about the educational environment and give important feedback to curriculum planners and change managers of the faculty for necessary improvement.

Interleukin-6 levels and HPA axis activation in breast cancer patients with major depressive disorder

An association or a casual link has been proposed between the neuroendocrinological and neuroimmunological changes attributed to either depression or cancer. This study investigated whether breast cancer patients with and without major depression exhibit plasma interleukin-6 abnormalities and dexamethasone suppression test results. Four groups, each consisting of 30 women (1--healthy women, 2--patients with major depression, 3--breast cancer patients without major depression, 4--breast cancer patients with major depression), were compared to each other. Psychiatric evaluations were made by structured clinical interview for DSM-IV. Severity of depression was measured with the Hamilton Depression Rating Scale. Plasma levels of interleukin-6 were measured. A dexamethasone suppression test was applied. Breast cancer patients with major depression had markedly higher plasma levels of interleukin-6 than the other group. All breast cancer patients with depression had abnormal dexamethasone suppression test results. These findings suggest a hypothalamo-pituitary-adrenal axis activation and plasma levels of interleukin-6 and plasma interleukin-6 elevation and plasma levels if interleukin-6 and plasma levels of post cortisol concentrations. Evidence for a casual link or association of major depression with immune and endocrinological activation needs to be investigated further.

Melatonin as a free radical scavenger in experimental head trauma

Head trauma causes two kinds of injury in the neural tissue. One is the primary injury which occurs at the time of impact. The other one is a secondary injury and is a progressive process. Free radicals are produced during oxidative reactions formed after trauma. They have been thought to be responsible in the mechanism of the secondary injury. Some studies have been conducted to demonstrate the role of free oxygen radicals in neuronal injury. The alterations in the free radical level during the early posttraumatic period and the effect of a free radical scavenger on these alterations have not been studied as a whole. We aimed to demonstrate the free oxygen radical level changes in the early posttraumatic period and the effect of melatonin, which is a potent free radical scavenger, on the early posttraumatic free radical level. A two-staged experimental head trauma study was designed. In stage one, posttraumatic free radical level changes were determined. In the second stage, the effect of melatonin on the free radical level changes in the posttraumatic period was studied. Two main groups of rats each divided into four subgroups were studied. Rats in one of the main groups underwent severe head trauma, and malondealdehyde (MDA) levels were measured in the contused cerebral tissue at different time points. Rats in the other main group also underwent the same type of trauma, and melatonin was injected intraperitoneally at different time points after trauma. The MDA level alteration in the tissue was determined after the injection of melatonin. The MDA level increased rapidly in the early posttraumatic period. But in time, it decreased in the groups with only trauma. In the melatonin-treated group, the MDA level decreased after the injection of melatonin, when injected in the early posttraumatic period, compared to the control and trauma groups. However, melatonin increased MDA to a higher level than in the groups with only trauma and the control group when injected later than 2 h after trauma. The MDA level increases in the very early posttraumatic period of cerebral trauma and decreases in time. Melatonin, which is the most potent endogenous free radical scavenger, when injected intraperitoneally to the cerebral traumatized rats in the very early posttraumatic period, causes a significant decrease in the MDA level. But, melatonin, when injected more than 2 h after trauma, increases the MDA level in experimental cerebral trauma in rats.

The possible modulation of morphine analgesia by the supramolecular GABA receptor complex

In the present study, the mechanism of the antagonistic action of 0.5 mg/kg diazepam on the analgesic effect of morphine was investigated. While Ro 15-1788, a benzodiazepine receptor antagonist, was found to partially reverse the inhibitory action of diazepam on morphine analgesia, a chloride channel blocking agent, picrotoxin, produced complete antagonism of the action of diazepam. Furthermore, picrotoxin potentiated the partial antagonistic effect of Ro 15-1788 at a normally ineffective dose to affect the 0.5 mg/kg diazepam-morphine dose-response curve. These overall effects of picrotoxin on the supramolecular GABA receptor complex are discussed.

The effects of flumazenil on two way active avoidance and locomotor activity in diazepam-treated rats

The present study was undertaken to determine the effects of chronic flumazenil treatment alone and simultaneously with diazepam on acquisition performance in an active-avoidance task and on locomotor activity in rats. Flumazenil (5, 10 and 20 mg/kg) and diazepam (0,5, 1.0 and 2.0 mg/kg) were administered intraperitoneally to rats before each daily training session for 5 days. The baseline of avoidance performance was set to approximately 50% and responses were expressed as acquisition rate. Locomotor activity of the rats was simultaneously recorded but only following the first training session. Diazepam decreased acquisition rate between the dose range used. Flumazenil had no effect on the acquisition rate of naive rats but reversed low dose diazepam-induced learning and memory impairment. Diazepam induced locomotor depression within the same dose range that decreased acquisition rate. Flumazenil had no effect on locomotor activity, but reversed the locomotor depressant effect of diazepam. The striking contradiction with previous data that flumazenil has no effect on learning-memory processing is discussed.

Behavioural assessment of pinealectomy and foetal pineal gland transplantation in rats: Part II

SummaryPineal gland is an endocrine organ which exerts regulatory effects on the activity of various organs and systems. The present study was undertaken to highlight in experimental animals the possible integrative function of this endocrine organ on a behavioural pattern. Pinealectomy and foetal pineal gland transplantation to a subpial cortical area close to the pinealectomized region was performed. Behaviour was defined through motor activity induced by low (2 mg/ kg) and high (10 mg/kg) doses of amphetamine in rats.It was shown that pinealectomy produced significantly different patterns of behaviour induced by low and high doses of amphetamine. In sham operated animals low dose amphetamine induced a significant locomotor stimulation but without stereotyped activity. High dose amphetamine induced stereotyped activity. After pinealectomy even low dose amphetamine preoduced the behavioural pattern of stereotyped activity resembling a high dose amphetamine-induced behaviour. This differential effect of amphetamine, seen in pinealectomized rats, was completely restored after transplantation.On the other hand, melatonin treatment did not generate a significant alteration of behavioural profile either in the control or pinealectomized group of rats.Results are discussed with regard to the general regulatory function of the pineal gland.

How we derived a core curriculum: from institutional to national—Ankara University experience

As the first phase of a major curricular change in a large medical school the core curriculum had to be determined. The criteria for the inclusion of topics in the core curriculum were defined for both clinical and basic sciences. A large group of faculty members have worked in 11 sub-groups to determine the core knowledge, skills and attitudes for undergraduate medical students. During this work 608 clinical topics have been reviewed. Four-hundred and eighty five of them (79%) have been included in the core curriculum. Clinical and basic science knowledge, skills and attitudes relevant to these topics have been defined and classified. A total of 1610 cognitive, 428 psychomotor skills and 247 attitudes have been named. Thus the core curriculum defined is not just a set of diseases, conditions and symptoms but also includes the details of each and every topic. Starting from this point the medical school has participated actively in defining the national core curriculum, which has also been determined according to the same criteria.

Segmental and age-dependent changes of histamine's affinity in the rabbit aorta

Affinities of contractile responses to histamine and H1-receptor agonists thiazolylethylamine (TEA) and pyridylethylamine (PEA) were evaluated in three segments of rabbit aorta and increase of affinity in the caudal direction was found. α-adrenergic afflnity of noradrenaline did not possess such differentiation. Evaluation of the data with histamine receptor agonists and antagonists suggested H1-receptor liability of the phenomena.Affinities of histamine and noradrenaline were also investigated in relation to body weight which reflects age. Histamines affinity was found to be age dependent, decreasing with the increase of age, while no correlation was found for noradrenaline between two parameters.Results are suggesting the presence of histamine specific vascular function in the rabbit which is receded by the advance of age.

The Art of Scientific Presentation

While scientific research data can only become widespread by scientific communication, scientists generally underestimate the importance of communicating effectively. The present article is a current informational review of the guidelines for effective oral and poster presentation for young scientists. Emphasis has been given not only to effective structuring of the content but to effective verbal and non-verbal presentation techniques as well. References are mostly Internet sources, thus, have not been cited throughout the article but given at the end as a whole.