Nifedipin ublažava djelovanje kokaina na enzimsku aktivnost u mozgu i jetri te smanjuje njegovo izlučivanje putem mokraće

The aim of this study was to see how nifedipine counters the effects of cocaine on hepatic and brain enzymatic activity in rats and whether it affects urinary excretion of cocaine. Male Wistar rats were divided in four groups of six: control, nifedipine group (5 mg kg-1 i.p. a day for five days); cocaine group (15 mg kg-1 i.p. a day for five days), and the nifedipine+cocaine group. Twenty-four hours after the last administration, we measured neuronal nitric oxide synthase (nNOS) activity in the brain and cytochrome P450 quantity, ethylmorphine-N-demethylase, and anilinehydroxylase activity in the liver. Urine samples were collected 24 h after the last cocaine and cocaine+nifedipine administration. Urinary cocaine concentration was determined using the GC/MS method. Cocaine administration increased brain nNOS activity by 55 % (p<0.05) in respect to control, which indicates the development of tolerance and dependence. In the combination group, nifedipine decreased the nNOS activity in respect to the cocaine-only group. In the liver, cocaine significantly decreased and nifedipine significantly increased cytochrome P450, ethylmorphine-N-demethylase, and anilinehydroxylase in respect to control. In combination, nifedipine successfully countered cocaine effects on these enzymes. Urine cocaine excretion in the cocaine+nifedipine group significantly dropped (by 35 %) compared to the cocaine-only group. Our results have confirmed the effects of nifedipine against cocaine tolerance and development of dependence, most likely due to metabolic interactions between them.Cilj je ovoga istraživanja bio utvrditi kako nifedipin ublažava djelovanje kokaina na enzimsku aktivnost u mozgu i jetri Wistar štakora te utječe li na njegovo izlučivanje putem mokraće. Mužjaci su podijeljeni u četiri skupine po šest jedinki: kontrolnu skupinu, nifedipinsku skupinu koja je pet dana intraperitonealno primala nifedipin u dozi od 5 mg kg-1; skupinu koja je pet dana primala kokain u dozi od 15 mg kg-1 na dan te skupinu koja je zajedno primala nifedipin i kokain u odgovarajućim dozama. Dvadeset i četiri sata nakon posljednje doze izmjerena je enzimska aktivnost sintaze dušičnoga oksida (nNOS) u mozgu, razina citokroma P450 te aktivnosti enzima etilmorfi n-N-demetilaze i anilinhidroksilaze u jetri štakora. Uzorci mokraće prikupljeni su 24 sata nakon posljednje doze kokaina odnosno kombinacije nifedipina i kokaina. Koncentracija kokaina u mokraći izmjerena je s pomoću vezanog sustava plinske kromatografi je i spektrometrije masa. Kokain je povećao aktivnost nNOS-a u mozgu za 55 % (p<0,05) u odnosu na kontrolnu skupinu, što upućuje na stvaranje tolerancije i ovisnosti. U kombiniranoj skupini nifedipin je značajno smanjio aktivnost nNOS-a u odnosu na skupinu koja je primila samo kokain. Kokain je značajno snizio, a nifedipin značajno povisio razinu citokroma P450 u jetri te aktivnost etilmorfi n-N-demetilaze i anilinhidroksilaze u odnosu na kontrolnu skupinu. U kombiniranoj skupini nifedipin je uspješno ublažio djelovanje kokaina na aktivnost spomenutih enzima. Izlučivanje kokaina putem mokraće u kombiniranoj skupini bilo je značajno manje (35 %) nego u skupini koja je primala samo kokain. Ovi rezultati potvrđuju da nifedipin štiti od djelovanja kokaina i stvaranja ovisnosti, najvjerojatnije zbog interakcija u metabolizmu dvaju spojeva

Protection by the NDI1 Gene against Neurodegeneration in a Rotenone Rat Model of Parkinson's Disease

It is widely recognized that mitochondrial dysfunction, most notably defects in the NADH-quinone oxidoreductase (complex I), is closely related to the etiology of sporadic Parkinson's disease (PD). In fact, rotenone, a complex I inhibitor, has been used for establishing PD models both in vitro and in vivo. A rat model with chronic rotenone exposure seems to reproduce pathophysiological conditions of PD more closely than acute mouse models as manifested by neuronal cell death in the substantia nigra and Lewy body-like cytosolic aggregations. Using the rotenone rat model, we investigated the protective effects of alternative NADH dehydrogenase (Ndi1) which we previously demonstrated to act as a replacement for complex I both in vitro and in vivo. A single, unilateral injection of recombinant adeno-associated virus carrying the NDI1 gene into the vicinity of the substantia nigra resulted in expression of the Ndi1 protein in the entire substantia nigra of that side. It was clear that the introduction of the Ndi1 protein in the substantia nigra rendered resistance to the deleterious effects caused by rotenone exposure as assessed by the levels of tyrosine hydroxylase and dopamine. The presence of the Ndi1 protein also prevented cell death and oxidative damage to DNA in dopaminergic neurons observed in rotenone-treated rats. Unilateral protection also led to uni-directional rotation of the rotenone-exposed rats in the behavioral test. The present study shows, for the first time, the powerful neuroprotective effect offered by the Ndi1 enzyme in a rotenone rat model of PD

Изучение фармакокинетического профиля лекарственного препарата Гидазепам®, таблетки, 50 мг в исследовании биоэквивалентности

Aim. The primary aim of this study was to evaluate the pharmacokinetic parameters and confirm the bioequivalence of drugs containing gidazepam, namely Gidazepam® (Valenta Pharm, Russia) and Gidazepam VIC (VIVA Pharm, Republic of Kazakhstan), after a single administration of 1 tablet (50 mg) to healthy volunteers under fasting conditions. The secondary aim was a comparative analysis of safety profiles (adverse events) after a single administration of the studied drugs.Materials and methods. An open, randomized, crossover, two-period comparative study of pharmacokinetics and bioequivalence with adaptive design was conducted in healthy volunteers. Blood sampling was performed 15 minutes before and 20 min, 40 min, 1 h, 2 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 6 h, 8 h, 12 h, 24 h, 48 h, and 72 h after drug administration. High-performance liquid chromatography-tandem mass spectrometry was used for the evaluation of gidazepam and its metabolite (desalkylgidazepam) concentration with the subsequent calculation of pharmacokinetic parameters.Results. From both formulations, gidazepam was quickly absorbed and biotransformed into an active metabolite. Studied drugs had similar pharmacokinetic profiles, as 90% confidence intervals for the ratio of geometric means for Cmax and AUC(0-72) were within the bioequivalence acceptance range of 80.00–125.00 %. No adverse events were recorded as a result of clinical, laboratory or instrument evaluations during the study.Conclusion. Study drugs are considered bioequivalent and show comparable tolerability after a single administration under fasting conditions.Цель исследования. Изучение фармакокинетики и подтверждение биоэквивалентности препаратов, содержащих гидазепам: Гидазепам® (АО «Валента Фарм», Россия) и Гидазепам VIC (ТОО «ВИВА ФАРМ», Республика Казахстан) при однократном приёме 1 таблетки (50 мг) здоровыми добровольцами натощак. Дополнительной целью исследования являлся сравнительный анализ данных о нежелательных явлениях при однократном приёме изучаемых препаратов.Материал и методы. Проведено открытое, рандомизированное, перекрёстное, двухпериодное с адаптивным дизайном исследование сравнительной фармакокинетики и биоэквивалентности с участием здоровых добровольцев. Отбор образцов крови осуществляли за 15 мин до приёма и через 20 мин, 40 мин, 1 ч, 2 ч, 3 ч, 3,5 ч, 4 ч, 4,5 ч, 5 ч, 6 ч, 8 ч, 12 ч, 24 ч, 48 ч и 72 ч после приёма лекарственных препаратов. С помощью метода высокоэффективной жидкостной хроматографии с тандемной масс-спектрометрией определяли концентрацию гидазепама и его метаболита (дезалкилгидазепама) для последующего расчёта фармакокинетических показателей.Результаты исследования. Гидазепам в составе двух сравниваемых лекарственных препаратов характеризовался быстрой абсорбцией и биотрансформацией с образованием активного метаболита. Препараты исследования обладали эквивалентным фармакокинетическим профилем, поскольку 90 % доверительные интервалы для отношения геометрических средних величин параметров Cmax и AUC(0–72) не выходили за установленные пределы 80,00–125,00 %. По данным клиниколабораторного и инструментального наблюдения за время проведения исследования у добровольцев не было зарегистрировано ни одного нежелательного явления.Заключение. Сравниваемые препараты являются биоэквивалентными и демонстрируют одинаковый профиль переносимости при однократном приёме натощак

Time to Switch to Second-line Antiretroviral Therapy in Children With Human Immunodeficiency Virus in Europe and Thailand.

Background: Data on durability of first-line antiretroviral therapy (ART) in children with human immunodeficiency virus (HIV) are limited. We assessed time to switch to second-line therapy in 16 European countries and Thailand. Methods: Children aged <18 years initiating combination ART (≥2 nucleoside reverse transcriptase inhibitors [NRTIs] plus nonnucleoside reverse transcriptase inhibitor [NNRTI] or boosted protease inhibitor [PI]) were included. Switch to second-line was defined as (i) change across drug class (PI to NNRTI or vice versa) or within PI class plus change of ≥1 NRTI; (ii) change from single to dual PI; or (iii) addition of a new drug class. Cumulative incidence of switch was calculated with death and loss to follow-up as competing risks. Results: Of 3668 children included, median age at ART initiation was 6.1 (interquartile range (IQR), 1.7-10.5) years. Initial regimens were 32% PI based, 34% nevirapine (NVP) based, and 33% efavirenz based. Median duration of follow-up was 5.4 (IQR, 2.9-8.3) years. Cumulative incidence of switch at 5 years was 21% (95% confidence interval, 20%-23%), with significant regional variations. Median time to switch was 30 (IQR, 16-58) months; two-thirds of switches were related to treatment failure. In multivariable analysis, older age, severe immunosuppression and higher viral load (VL) at ART start, and NVP-based initial regimens were associated with increased risk of switch. Conclusions: One in 5 children switched to a second-line regimen by 5 years of ART, with two-thirds failure related. Advanced HIV, older age, and NVP-based regimens were associated with increased risk of switch