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Sofia, Bulgaria

Vitcheva V.,Medical University-Sofia
Current Medicinal Chemistry | Year: 2012

Cocaine belongs to the group of psychostimulants and together with amphetamines has been recognized as one of the most significant examples of drug abuse. Cocaine abuse is due to intense feelings of euphoria, friendliness, empathy, and hyperactivity, which result from its potent inhibitory effects on presynaptic dopamine and noradrenaline re-uptake. Misuse of cocaine can induce severe toxic effects, including neurotoxicity, cardiotoxicity, hepatotoxicity. There are a number of data, both experimental and clinical, regarding its hepatotoxic effects, associated with lipid peroxidation-induced oxidative damage. The oxidative metabolism of cocaine to reactive oxygen species (ROS) like nitrogen peroxide and superoxide anion radicals are thought to be responsible for the cocaine associated liver injury. This review summarizes the present information on cocaine hepatic biotransformation and the possible role of its oxidative metabolism in cocaine-induced hepatic injury. © 2012 Bentham Science Publishers. Source

Popova E.,Medical University-Sofia
Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology | Year: 2014

Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences. © 2014 Springer-Verlag Berlin Heidelberg. Source

The effects of dopamine receptor blockade by sulpiride (D2-class antagonist) and sulpiride plus SCH 23390 (D1-class antagonist) on the V - log I function of the electroretinographic (ERG) b- and d-waves were investigated in light-adapted frog eyes. Sulpiride significantly decreased the absolute sensitivity of the b- and d-waves. The amplitude of the both waves was diminished over the whole intensity range studied. A similar effect on the b-, but not d-wave amplitude was seen during the perfusion with sulpiride plus SCH 23390. The effect on the d-wave amplitude depended on stimulus intensity. The threshold of the d-wave was not significantly altered. The suprathreshold d-wave amplitude was enhanced at the lower stimulus intensities and remained unchanged at the higher ones. The results obtained indicate that the action of endogenous dopamine on the photopic ERG shows clear ON-OFF asymmetry. Participation of different classes of dopamine receptors is probably responsible for this difference. © 2013 Springer-Verlag Wien. Source

Introduction. Diabetic neuropathy (DN) is one of the key pathogenetic factors for diabetic erectile dysfunction (DED). Aim. The aim of this study was to compare the effect of the first intake of tadalafil and vardenafil in men with DN and DED. Methods. In this comparative prospective randomized study were included 49 phosphodiesterase type 5 (PDE5) inhibitor-naïve men (80% type 2 diabetes). DN was assessed by a modified Neuropathy Disability Score (NDS≥3). Each patient received two pills containing 20mg of either tadalafil (N=24) or vardenafil (N=25). They had to be taken after discharge from the hospital at a time interval of at least 3 and 1day, respectively, and 1 to 6 hours before the intended sexual activity. Main Outcome Measures. The treatment efficacy was evaluated by the changes in the erectile domain of International Index of Erectile Function (IIEF), Sexual Encounter Profile Question 2 (SEP2) and 3 (SEP3), and the Global Assessment Question (GAQ). Results. For all patients, IIEF increased from 12.6±6.8 to 19.6±9.0 (P<0.001) points after treatment. The number of men with positive answers on SEP2 increased from 27 (55.1%) to 38 (77.6%), on SEP3 from 7 (14.3%) to 30 (61.2%). Thirty-one (63.3%) evaluated the effect of the drugs as beneficial (GAQ). No significant efficacy difference between tadalafil and vardenafil was observed. The initial indicators for DED, as well as the treatment efficacy, correlated highly significant with NDS. Both PDE5 inhibitors were well tolerated. Before entering the study, 28% of men have seen a physician, but only 57.1% of them have started treatment. Conclusions. In this study design, tadalafil and vardenafil are equally effective with the first intake in patients with diabetes and DN. Baseline indicators of erectile dysfunction and the ones verifying the effect of the treatment show significant correlation with the DN indicator-NDS. Tadalafil and vardenafil are well tolerated with no serious side effects. © 2010 International Society for Sexual Medicine. Source

STUDY DESIGN.: Randomized prevention trial. OBJECTIVE.: To compare the long-term effect of strengthening versus flexibility exercises and to evaluate the additional effect of abdominal bracing in recurrent low back pain ( LBP). SUMMARY OF BACKGROUND DATA.: No conclusions could be made regarding appropriate exercise types or parameters in recurrent LBP. Abdominal bracing increases trunk stiffness; however, its long-term effect has not been evaluated in recurrent LBP yet. METHODS.: Six hundred patients with recurrent LBP participated. They were randomized into 4 groups-150 patients ( age: 42.5 ± 12.7) performed strengthening exercises; 150 patients ( age: 41.3 ± 11.5) performed flexibility exercises; 150 patients ( age: 41.0 ± 13.2) performed strengthening exercises and used abdominal bracing in daily activities/ exercises; and 150 patients ( age: 40.6 ± 12.3) performed flexibility exercises and used abdominal bracing in daily activities/exercises. At the beginning of the study and at the end of 10 consecutive years were recorded 6 outcomes-frequency, intensity, and duration of pain, as well as frequency, intensity, and duration of exercises. RESULTS.: Regarding the first 4 outcomes-all groups showed improvement from the beginning to the second year, but worsening from the second to the 10th year; there was no difference between strengthening and flexibility groups; bracing groups showed better results versus nonbracing groups. Intensity, frequency, and duration of the pain correlated with each other and with frequency of the exercises, but not with exercise duration or intensity. CONCLUSION.: The exercise frequency is more important than the type, duration, or intensity of the exercise. Abdominal bracing adds to the exercise effect. It could be considered as a "preliminary muscle back belt on demand" increasing the trunk stiffness and the frequency of the trunk muscle contractions/cocontractions without interruption of daily activities, which may remind/convince the patients to exercise more frequently. Frequent exercising and bracing seems effective long-term prevention advices in recurrent LBP. © 2014, Lippincott Williams and Wilkins. Source

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