Efficacy, safety and tolerability of vidofludimus in patients with inflammatory bowel disease: the ENTRANCE study

BACKGROUND

Vidofludimus (SC12267) is a novel oral immunomodulator inhibiting dihydroorotate dehydrogenase (DHODH) and the expression of proinflammatory cytokines including interleukin-17 (IL17A and IL17F) and interferon-gamma. The objective of the study was to explore the efficacy, safety and tolerability of vidofludimus in steroid-dependent inflammatory bowel disease (IBD).

METHODS

The open label uncontrolled ENTRANCE study (ClinicalTrials.gov NCT00820365) has been conducted at 13 study centers in Germany, Bulgaria and Romania. Thirty-four steroid-dependent patients with a confirmed diagnosis of Crohn's disease (CD) or ulcerative colitis (UC) were treated with a once daily 35mg oral dose of vidofludimus over 12weeks. Steroids were tapered during the first 8weeks followed by a steroid-free treatment period of 4weeks. Complete response was defined as steroid-free clinical remission at week 12; partial response was defined as being in remission at steroid dose equal or lower than the individual patient's threshold dose for relapse.

RESULTS

Of the thirty-four patients enrolled in this trial 26 were evaluable for primary efficacy assessment. After completion of the 12weeks treatment phase 8 out of 14 (57.1%) patients with CD and 6 out of 12 (50.0%) patients with UC were in steroid-free remission (complete responders). Another 4 (28.6%) patients in CD and 5 (41.7%) patients in UC were partial responders. Vidofludimus was well tolerated, no drug-related serious adverse events were observed.

CONCLUSIONS

This trial provides first evidence of clinical efficacy of vidofludimus in IBD. Although the safety and tolerability profile seems favorable, long-term controlled studies are needed to further investigate its potential as novel IBD therapy.

Localized eczema herpeticum with unilateral ocular involvement

We report a case of eczema herpeticum with unilateral ocular involvement in a 16-year-old boy. The patient has had a mild form of atopic dermatitis (AD) since early childhood. Why AD patients are prone to herpes simplex virus (HSV) infections is still unclear. Ocular pathologic findings in these cases are rarely reported.

Dose-dependent effects of caffeine on behavior and thermoregulation in a chronic unpredictable stress model of depression in rats

The effects of the non-selective adenosine A(1)/A(2) receptor antagonist caffeine on behavior and thermoregulation in chronic unpredictable stress (CUS) model of depression was studied in Wistar rats. In the open field (OF) test, caffeine dose-dependently increased motor activity while decreased grooming and time spent in the corner. Five-week exposure to CUS procedure had the opposite effect in rats. Caffeine reversed CUS-induced effects on the above mentioned parameters. Caffeine (40 mg/kg) increased the motor activity in plus maze (PM) test while at doses of 20 and 40 mg/kg it decreased the number of entries in the open arms. Whereas CUS did not change the level of anxiety, caffeine (2, 20 and 40 mg/kg) administered after CUS diminished it by increasing the time in open arms. Caffeine dose-dependently decreased the immobility time while CUS had the opposite increasing effect in forced swimming test (FST). Caffeine at doses of 20 and 40 mg/kg reversed the effect of CUS on immobility in FST. Caffeine produced dose-dependent rice of body temperature in both non-treated and CUS-treated rats. The hyperthermic effect in normal rats pretreated with caffeine lasted about 90 min while in caffeine-pretreated rats exposed to CUS it lasted about 150 min. High dose of caffeine (100mg/kg) induced significant hypothermia between 90th and 150th minute in control rats and hyperthermia between 30th and 60th minute in CUS-treated rats. These results suggest a putative role of this methylxanthine in the adaptive responses to chronic unpredictable stress stimuli.

Estrogen replacement therapy and Alzheimer's disease

Estrogen replacement therapy (ERT) is increasingly recommended for postmenopausal women due to its numerous beneficial effects on bone, cardiovascular system, brain function and quality of life. Data from retrospective epidemiological studies have shown that ERT has a potential to reduce the risk for developing Alzheimer's disease (AD) and to delay its progression. In addition, recent clinical studies have reported improvement of cognitive functions in women with AD. Findings from basic science indicated that the possible mechanisms of action by which estrogen may affect AD include interaction with cholinergic neurotransmitter system, cholinergic neurotrophic and neuroprotective effect, improvement of learning and memory, improvement of cerebral blood flow and metabolism, antioxidant and antiinflammatory action, and interference with beta-amyloid protein metabolism and toxicity. Estrogen use in postmenopausal women may offer a new approach for improving cognitive functions in nondemented and demented women, delaying the onset and progression of AD and reducing its occurrence. However, prospective clinical trials are required to establish the efficacy of ERT for prevention and treatment of AD.

[Adult respiratory distress syndrome--etiology and pathogenesis]

Adult respiratory distress syndrome (ARDS) is not a specific lung disease. It represents an acute respiratory insufficiency syndrome in patients with non-injured lung as a result of severe multiple lung lesions of different etiology and pathogenesis. ARDS is provoked by a great number of etiologic factors of two main groups: 1) etiologic factors directly injuring the alveolo-capillary wall and 2) etiologic factors indirectly injuring the alveolo-capillary wall. ARDS develops in three phases: phase of exudation, phase of injury of the alveolocapillary wall and phase of proliferation (chronic phase).

[Interleukins and endocrine function]

Views and experimental data on the role of interleukins in the regulation of the endocrine functions of hypothalamus, pituitary gland, thyroid gland, suprarenal gland and pancreas are presented. The role of interleukin-1 and interleukin-6 in the regulation of normal and pathological processes is examined. Data on cellular and molecular operation mechanisms of some interleukins on functions of the endocrine glands are included in the survey. The clarification of these mechanisms leads to new pharmacotherapeutical approaches to endocrine diseases treatment.

Enhanced sensitivity of insulin-resistant adipocytes to vanadate is associated with oxidative stress and decreased reduction of vanadate (+5) to vanadyl (+4)

Vanadate (sodium orthovanadate), an inhibitor of phosphotyrosine phosphatases (PTPs), mimics many of the metabolic actions of insulin in vitro and in vivo. The potential of vanadate to stimulate glucose transport independent of the early steps in insulin signaling prompted us to test its effectiveness in an in vitro model of insulin resistance. In primary rat adipocytes cultured for 18 h in the presence of high glucose (15 mm) and insulin (10(-7) m), sensitivity to insulin-stimulated glucose transport was decreased. In contrast, there was a paradoxical enhanced sensitivity to vanadate of the insulin-resistant cells (EC(50) for control, 325 +/- 7.5 microm; EC(50) for insulin-resistant, 171 +/- 32 microm; p < 0.002). Enhanced sensitivity was also present for vanadate stimulation of insulin receptor kinase activity and autophosphorylation and Akt/protein kinase B Ser-473 phosphorylation consistent with more effective PTP inhibition in the resistant cells. Investigation of this phenomenon revealed that 1) depletion of GSH with buthionine sulfoximine reproduced the enhanced sensitivity to vanadate while preincubation of resistant cells with N-acetylcysteine (NAC) prevented it, 2) intracellular GSH was decreased in resistant cells and normalized by NAC, 3) exposure to high glucose and insulin induced an increase in reactive oxygen species, which was prevented by NAC, 4) EPR (electron paramagnetic resonance) spectroscopy showed a decreased amount of vanadyl (+4) in resistant and buthionine sulfoximine-treated cells, which correlated with decreased GSH and increased vanadate sensitivity, while total vanadium uptake was not altered, and 5) inhibition of recombinant PTP1B in vitro was more sensitive to vanadate (+5) than vanadyl (+4). In conclusion, the paradoxical increased sensitivity to vanadate in hyperglycemia-induced insulin resistant adipocytes is due to oxidative stress and decreased reduction of vanadate (+5) to vanadyl (+4). Thus, sensitivity of PTP inhibition and glucose transport to vanadate is regulated by cellular redox state.

[Macrolides: pharmacology and clinical use]

Members of macrolides are Erythromycin, Oleandomycin, Spiramycin, Roxithromycin, Josamycin, Midecamycin, Clarithromycin, Azithromycin and Dirithromycin. This review present mechanism of action, pharmacokinetic, adverse drug reactions and main clinical uses of the macrolides.

Alzheimer's disease therapy - an update

The 5th International Geneva/Springfield Symposium on Advances in Alzheimer Therapy focused on new therapeutic approaches for the treatment of Alzheimer 's disease (AD) based on the latest basic science data. The two major pharmacological principles of cholinergic therapy are 1) reduction of acetylcholine hydrolysis by means of acetylcholinesterase (AChE) inhibitors; and 2) direct stimulation of nicotinic or muscarinic receptors with selective agonists. Currently used AChE inhibitors are tacrine, donepezil hydrochloride, rivastigmine and metrifonate. In the area of muscarinic and nicotinic receptor modulation, studies were presented on AF-102B and AF-150(S), BIBN-99, CI-1017, RJR-2403, ABT-418, ABT-089, GTS-21 and SIB-1553A. Based on evidence of inflammatory mechanisms in the pathogenesis of AD, selective COX-2 inhibitors for the prevention and treatment of AD are a target of several pharmaceutical companies. Concerning known antiinflammatory drugs, results from controlled trials are expected soon. Estrogen replacement has been reported to produce cognitive and affective improvement in women with AD, and results from a number of studies were presented. Age-associated increases in oxidative stress may play a role in AD and thus antioxidants may also have a place in the therapy of this disease. The antioxidants vitamin E and selegiline are being investigated. Other drugs under investigation are propentofylline, Cerebrolysin, citicoline sodium, CDP-choline, memantine, Egb-761, calagualine and AIT-082. Iododoxorubicin may represent a new class of compounds able to interfere with the beta-amyloid cascade in AD and other brain amyloid diseases. Future preventive strategies in AD include genotype analysis and screening, presymptomatic diagnosis and avoidance of environmental risk factors.

Antiamyloid strategies for the treatment of Alzheimer's disease

Although the specific causes of Alzheimer's disease have not yet been determined, considerable circumstantial evidence implicates beta-amyloid, an insoluble polypeptide made up of 39 to 42 amino acids, in the continuing destruction of brain cells that results in the progressive deterioration of the patient's mental ability. The toxic actions of beta-amyloid appear to be due to free radicals generated by a portion of the beta-amyloid molecule. These free radicals damage various parts of the neuron and lead to increased intracellular calcium which is also toxic. beta-Amyloid is formed by the aberrant processing of a much larger precursor protein that is made when cells are damaged. The normal processing of this precursor protein not only prevents the formation of beta-amyloid, but produces a soluble protein that regulates the entry of calcium into neurons and has cytoprotective actions. Interventions to prevent the destruction of neurons and the disruption of brain function by beta-amyloid include the administration of antioxidants and free radical scavengers to reduce further neural damage from deposits of beta-amyloid, the activation of various growth factors to repair damaged cells and restore their functions, and the stimulation of the normal processing of the precursor protein not only to aid in neural repair but more importantly to prevent the formation of additional beta-amyloid.

Evaluation of an ion-selective electrolyte analyzer: Microlyte 6

Microlyte 6 (Kone, Finland) is an ion-selective analyzer designed to measure simultaneously the concentration of six important electrolyte parameters--potassium, sodium, chloride, ionized calcium, ionized magnesium and pH in whole blood, serum and plasma. Two values are obtained in analyzing the ionized fractions of magnesium and calcium--one at the actual pH and another at a recalculated measurement for pH = 7.4. Direct determination of ionized calcium and ionized magnesium simultaneously with that of the other electrolytes is of great clinical significance. It is only recently that ion-selective analysis of ionized magnesium has been proposed. The analytical reliability of the results and the operational characteristics of the Microlyte 6 ion-selective analyzer were evaluated for approximately one year. The coefficient of variation of the results in the reference and pathological range was 0.49%-2.23%, and 0.68%-4.42% for the within-run and between-run series, respectively. The inaccuracy of the results expressed by d% was from -4.23% to +4.06%. The comparative evaluation of the results for potassium, sodium, chloride, and ionized calcium between Microlyte-6 and the clinical chemistry analyzer Dynamic (Kone) showed a high correlation (correlation coefficient in the range 0.9868-0.9970). The correlation between the results for the ionized fraction and those obtained for total magnesium was consistent with that generally given in the literature.

Central effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) in mice

The central effects of endothelin-1 (ET-1, 0.5, 1, 2.5 and 10 pmol/mouse) and endothelin-3 (ET-3, 2.5, 5, 10, 20 and 25 pmol/mouse) have been studied after intracerebroventricular (i.c.v.) administration in mice. The following methods were used: behavioral observations, rotarod, spontaneous and amphetamine-stimulated motor activity, and hexobarbital-induced narcosis. ET-1 and ET-3 evoked a dose-dependent behavioral syndrome with a short excitatory period in the higher doses lasting for 5-10 min, followed by a prolonged depressive phase (about 90 min). ET-1 and ET-3 produced central depressive effects demonstrated by depressive behavior signs, decrease of the spontaneous and amphetamine-stimulated motor activity, and prolongation of the hexobarbital-induced narcosis.

Involvement of Ca2+ and alpha 1-adrenoceptors in endothelin-1 effects on the tone and electrically evoked contractions of rabbit ear central artery

Endothelin-1 (ET-1) is a neuropeptide strongly involved in the functions of the cardiovascular system. The aim of the present study was to reveal the role of alpha1-adrenoceptors and of Ca2+ in the effects of ET-1 on blood vessels. Preparations isolated from the proximal part of ear central arteries (REA) of male Chinchilla rabbits were used. A 30-40 mm long segment, cannulated at both ends, was fixed in an organ bath with Krebs-Henseleit solutions aerated with 95% O2 and 5% CO2. The preparations were perfused at a rate of 3.0 ml/min maintaining the arterial pressure in the range of 40-60 HPa and were allowed a 120-min adaptation at 37.5 degree C. Contractions were induced by low-frequency electrical stimulation (ES) and the effects of ET-1 (applied intralumenally or extralumenally) on the arterial tone and on the Es-evoked contractions were studied. Extralumenal ET-1 (1 x 10(-12)M-1 x 10(-9)M) did not change the tone and ES evoked contractions of REA. In concentrations of 1 x 10(-8)M-1 x 10(-7)M ET-1 slightly increased arterial tone and moderately potentiated ES contractions. ET-1, in concentrations higher than 1 x 10(-7)M, sharply, strongly and long-lastingly increased the smooth muscle tone and slightly enhanced the ES contractions. A 100 microM bolus injection with ET-1 (1 x 10(-9)M-1 x 10(-8)M) resulted in potentiation of the ES contractions and the arterial tone was not markedly affected. 100 microM of 1 x 10(-7)M ET-1 increased more than 2-fold the tone of the segments and moderately reduced the ES-evoked contractions. A 30-min perfusion with ET-1 (1 x 10(-12)M-1 x 10(-9)M) strongly increased the arterial tone and completely abolished the ES contractions. Perfusion with 1 x 10(-8)M ET-1 resulted in a 3-fold increase of the tone of the isolated segments. A 30-min perfusion with 1 x 10(-6)M prazosin (PRZ) did not affect the arterial tone and prevented the ES-evoked contractions. PRZ markedly reduced the contractile effects of 1 x 10(-12)M-1 x 10(-9)M ET-1 and the effect of 1 x 10(-8)M ET-1 on REA tone was even enhanced by PRZ. Under the same conditions 1 x 10(-6)M flunarizine (FLU) inhibited the ES-induced contractions of the isolated preparations and decreased their tone. FLU reduced the contractile effects of ET-1 (1 x 10(-12)M-1 x 10(-8)M). Applied extralumentally 1 x 10(-6)M FLU also decreased EG-1 effects on REA. The results obtained strongly support the assumption that alpha1-receptors and Ca2+ are involved in ET-1 contractile effects on blood vessels smooth muscles.

L-NAME augments the antinociceptive effects of intracerebroventricularly applied ET-1 and ET-3

The interaction between endothelin-1 (ET-1) (5 pmol/mouse, i.c.v.) and endothelin-3 (ET-3) (5 pmol/mouse, i.c.v.) with NG-nitro-L-arginine methyl ester (L-NAME) (5 mg/kg i.p., 30 min pretreatment) was investigated in mice by the use of two experimental procedures: hot plate and tail flick tests in mice. L-NAME showed slight insignificant antinociceptive action, but augmented significantly the antinociceptive effects of i.c.v. administered ET-1 and ET-3 in both experimental tests.

Antinociceptive effect of centrally administered endothelin-1 and endothelin-3 in the mouse

The antinociceptive effects of centrally administered (i.c.v.) endothelin-1 (ET-1) and endothelin-3 (ET-3) were studied in mice by the use of 3 experimental procedures: hot plate, tail flick and acetic acid writhing tests. ET-1 (0.625-5 pmol/mouse) and ET-3 (2.5-25 pmol/mouse) produced statistically significant increase of the hot plate and tail flick latencies with duration of about 120 min. ET-3 showed weaker antinociceptive effect. ET-1 inhibited acetic acid-induced writhings with ED50 = 1.9 (1.1-2.7) pmol/mouse. With ET-3 a maximum effect of 45.2% suppression of the writhing response was achieved at 5 pmol/mouse. The antinociception due to ET-1 and ET-3 was not antagonized by naloxone and is thus independent of endogenous opioid release.

Endothelin-1 exacerbates focal cerebral ischemia without exerting neurotoxic action in vitro

In a model of focal cerebral ischemia in mice, intracisternal injection of 5 and 10 pmol/mouse endothelin-1 significantly increased the infarcted surface area by 15.5% and by 23.5%, respectively. Endothelin-1 (0.01, 1, and 100 nmol/l) added to the primary neuronal cultures of chick embryo cerebral hemispheres for 1 h and 24 h did not influence the viability of the neurons or the protein content of the cultures. When applied simultaneously with 1 mmol/l sodium cyanide for 30 min, endothelin-1 (0.01, 1, and 100 nM) did not modify the hypoxia-induced changes. The results show that exogenously applied endothelin-1 could exacerbate cerebral ischemia, probably due to its vasoconstrictive properties and not to a direct neurotoxic effect.

Studies on the effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) in brain hypoxia and on the participation of brain prostanoids in their actions

The effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) in brain hypoxia have been studied in mice using the following experimental models: hypobaric hypoxia induced by low atmospheric pressure, histotoxic hypoxia induced by 12.5 mg/kg KCN i.p., and complete ischemia induced by decapitation. ET-1 and ET-3 were injected intracerebroventricularly (i.c.v.) 15 min before the tests. Forebrain tissue concentrations of 6-keto-PGF1 alpha and thromboxane B2 (TxB2) were measured 15 min following i.c.v. administration of ET-1 (5 pmol/mouse) and ET-3 (10 pmol/mouse). ET-1 (1-5 pmol/mouse) and ET-3 (5-25 pmol/mouse) showed a dose-dependent increase in the survival/gasping time in all models of hypoxia. The effect reached its maximum between 15 and 30 min after ET administration and lasted for about 120 min. ET-1 and ET-3 did not significantly change the brain levels of 6-keto-PGF1 alpha and TxB2. The protective effect of ET-1 and ET-3 was unexpected, because endothelins (ETs) are the most potent vasoconstrictors known, and in doses close to those used in this study they cause vasoconstriction and decrease in cerebral blood flow. The protection was not likely to be due either to stimulation of the endogenous release of prostacyclin (PGI2) or to a decrease in the deleterious prostanoid thromboxane A2 (TxA2). Additional experiments are necessary to explain the cerebroprotective effects of ET-1 and ET-3.

Effects of intracerebroventricular endothelin-1 on CNS and cerebral hypoxia/ischemia and their modification by cinnarizine

The central effects of endothelin-1 (ET-1) and their modification by the calcium entry blocker cinnarizine have been investigated using CNS and hypoxia/ischemia tests. CNS tests comprised behavior, horizontal and vertical motor activity and hot plate test. Hypoxia/ischemia tests used were hypobaric hypoxia and complete ischemia by decapitation. ET-1 was injected intracerebroventricularly (i.c.v.) in a volume of 0.01 ml at doses of 1.25, 2.5 and 5 pmol/mouse 15 min before the tests. Cinnarizine (10 mg/kg, i.p.) was administered 60 min prior to ET-1. The i.c.v. ET-1 at all the doses used decreased horizontal and vertical motor activity and produced barrel-rolling. Survival/gasping time of mice subjected to hypoxia/ischemia increased dose-dependently. ET-1 showed an antinociceptive effect. Cinnarizine attenuated the appearance of barrel-rolling, did not antagonize disturbances in motor activity and reversed the antinociceptive effect of ET-1. In hypobaric hypoxia and decapitation cinnarizine antagonized the effects of 5 pmol/mouse ET-1 and potentiated that of 1.25 pmol/mouse. The pharmacological modification of the ET-1 effects by cinnarizine strongly suggests that the CNS actions of ET-1 might be due to multiple mechanisms triggered by an increased influx of extracellular Ca2+ into the brain cells.

Clinical meaning of GGT activity in follow-up of patients with alcohol-related liver injury and cholestasis

The dynamics of GGT was investigated in three groups of patients after removing some primary causes of GGT increase. Group A included 34 patients with alcohol-related liver disease, group B included 16 patients with alcoholic liver injury and cholestasis, caused by concomitant alcoholic pancreatitis and group C included 17 patients with extrahepatic cholestasis, caused by choledocholithiasis. Follow-up assays of GGT were performed on the 7th, 14th and 30th days. Our results showed that the dynamics of GGT was more rapid after removing the cause for cholestasis than in stopping alcohol consumption in patients with chronic liver diseases. On the 14th day more than a 50% decrease in GGT activity was noted in 20% of the patients from groups A and B and in almost all cases from group C. On the 30th day, the reference range of GGT was not attained by any of the patients with liver disease nor in five patients from group C. No significant correlation was found between the severity of liver damage and the extent of GGT increase at the beginning and at the end of the follow-up period.

Intracerebroventricular endothelin-1 (ET-1) produces Ca(2+)-mediated antinociception in mice

Intracerebroventricular (i.c.v.) administration of endothelin-1 (ET-1) at doses of 0.313, 0.625, 1.25, 2.5 and 5 pmol/mouse produced a strong antinociceptive effect as evaluated by hot plate method in mice. The effect was dose-dependent and lasted for more than 120 min. The opioid receptor antagonist naloxone did not antagonize, and the cyclooxygenase inhibitors indomethacin and diclofenac slightly inhibited the ET-1 effect. The calcium overload blocker cinnarizine antagonized the antinociceptive effect of ET-1, suggesting that the ET-1 effect might be Ca(2+)-mediated.

Study on the cerebral effects of sabeluzole

The cerebral effects of subeluzole have been studied using the following methods: hypobaric hypoxia in mice, complete ischemia by decapitation in mice, anoxic hypoxia in mice, hemic hypoxia in rats, incomplete ischemia by bilateral carotid ligation in rats, anoxic hypoxia in rats and asphyxic hypoxia in cats. Sabeluzole was active in all the models used: it increased the survival time in hypobaric hypoxia (maximum at 40 mg/kg--by 92.0%, p less than 0.001), survival time in anoxic hypoxia in mice (maximum at 40 mg/kg--by 27.2%, p less than 0.001), gasping in decapitation model (maximum at 20 mg/kg--by 155.4%, p less than 0.001) and survival in hemic hypoxia (maximum at 2.5 mg/kg--by 21.1%, p less than 0.05). The duration of the effect as evaluated in the decapitation model was about 6 h. In incomplete ischemia in rats, however, it showed a weak effect. In anoxic hypoxia in rats, sabeluzole (5 mg/kg i.v.) increased the time latency between onset of anoxia and negative DC-shift by 20.5% and the K+e-threshold by 25.7%. In asphyxic hypoxia in cats, sabeluzole (0.5 mg/kg i.v.) counteracted the hypoxia-induced decrease of the fast-wave amplitudes during the cortical resistance period and the hypoxia-induced decrease of the slow-wave and increase of the fast wave amplitudes during the cortical recovery period.

Rheoencephalographic and electroencephalographic studies on flunarizine

The effect of flunarizine on the rheoncephalogram (REG) and on spontaneous electroencephalographic activity (EEG) was studied in acute experiments in cats. The following REG parameters were assayed: amplitude, anacrotic section of the curve and its relative part, and dicrotic index. EEG spectra were derived from 10-sec samples of EEG and the relative amplitudes were estimated at 2 Hz-intervals from 0-40 Hz. The REG study showed that flunarizine (2.5 and 5 mg/kg i.v.) caused an increase of the amplitude and a decrease of the anacrote, of its relative part, and the dicrotic index, changes indicating a lowering of the cerebrovascular resistance. EEG study showed a decrease of the amplitudes of the alpha-frequency band, and an increase of the fast-waves amplitudes, most pronounced at 5 mg/kg, changes showing enhancement of the activation processes in the brain cortex.

Cerebroprotective effect of flunarizine

The cerebroprotective effect of flunarizine was studied using the following methods: hypobaric hypoxia in mice, complete ischemia by decapitation in mice, anoxic hypoxia in mice, hemic hypoxia in rats, incomplete ischemia by bilateral carotid ligation in rats and asphyxic hypoxia in cats. Piracetam, meclofenoxate, nicergoline, naftidrofuryl, cinnarizine and nifedipine were studied as reference drugs. Flunarizine increased the survival time in all survival models. Its effect was most pronounced in complete ischemia model, and considerably higher than that of reference drugs. In asphyxic hypoxia flunarizine increased cortical resistance and shortened cortical recovery. The EEG frequency-amplitude analysis during asphyxic hypoxia showed a significant decrease of the slow-waves amplitudes of delta and theta range, and an increase of the fast-waves amplitudes of beta-2 range, changes indicating protective action.

Rheoencephalographic and electroencephalographic studies on nicergoline

The effect of nicergoline on the rheoencephalogram (REG) and on spontaneous electroencephalographic activity (EEG) was studied in acute experiments in cats. The following REG parameters were assayed: amplitude, anacrotic section of the curve and its relative part and dicrotic index. EEG spectra were derived from 10-sec samples of ECoG and the relative amplitude was estimated at 2 Hz-intervals from 0-44 Hz. The REG study showed that nicergoline (0.05 mg/kg i.v.) caused an increase of the amplitude, and a decrease of the anacrote, of the relative part of the anacrote and the dicrotic index - changes indicating a lowering of cerebrovascular resistance. EEG study showed a decrease of the slow activities (theta and delta), and an increase of the fast activities (alpha and beta-1).

Eicosanoids in rat brain during ischemia and reperfusion--correlation to DC depolarization

The effects of complete ischemia on cerebral arachidonic acid (AA) metabolism were investigated in the isolated perfused rat brain. During 12.5 min of ischemia, AA, 5-hydroxy-6,8,11,14-eicosatetraenoic acid, and 15-hydroxy-5,8,11,13-eicosatetraenoic acid increased 129-, 4-, and 10-fold, respectively, while subsequent reperfusion for 30 min resulted in normalized levels independently of the duration of preceding ischemia. Prostaglandin (PG) F2 alpha, PGE2, PGD2, 6-keto-PGF1 alpha, and thromboxane (Tx) B2 remained at preischemic levels during 12.5 min of complete ischemia. However, at the end of subsequent reperfusion for 30 min, the levels of the prostanoids PGF2 alpha, PGE2, PGD2, 6-keto-PGF1 alpha, and TxB2 increased according to the preceding ischemic time. The levels reached a maximum after 7.5 min of ischemia and were elevated by 7-, 14-, 48-, 3-, and 30-fold, respectively. A prolongation of ischemia of up to 12.5 min was not associated with further increases of prostanoids at the end of reperfusion. The mechanisms underlying the metabolism of eicosanoids are discussed in relation to the changes of cortical direct current potential.

Effects of nicergoline in experimental models related to pathogenesis of migraine

The effect of nicergoline on cerebral blood flow (CBF), cerebrovascular resistance, the constriction of cerebral vessels caused reflectorily or by 5-hydroxytryptamine (5-HT) and on the transport of 5-HT in rat brain synaptosomes was studied using different experimental models. Nicergoline reduced cerebrovascular resistance in the carotid and vertebrobasilar system. The drug decreased carotid blood flow and local cortical CBF, preceded in some experiments by short-lasting CBF increase. Nicergoline almost completely inhibited brain vessels responses in the carotid and vertebrobasilar systems after tibial nerve stimulation. Simultaneously, inhibition of reflectory discharges of the sympathetic nerves was observed. Nicergoline showed an antiserotonin action by antagonizing the 5-HT effect on the cerebral circulation and inhibiting 5-HT-induced constriction of isolated rabbit basilar artery. The inhibition of uptake and enhancement of the release of 5-HT from brain synaptosomes indicates its ability to affect neuronal transmission in serotoninergic neurons. The effects of nicergoline are probably involved in the realization of its antimigraine action.

Streptozotocin-induced diabetes in rat. III. Antioxidant protection of vascular complications by flunarizine and aligeron

In rats with streptozotocin-induced diabetes antioxidant protection of diabetic angiopathy was performed by flunarizine (10 mg/kg/day) and aligeron (10 mg/kg/day), applied intraperitoneally during 2.5 months of diabetes. Diabetic vascular complications were assessed by morphologic determination of PAS-positive mucopolysaccharides and measurement of vascular wall thickness in addition to quantitative estimation of lipid hydroperoxides, thromboxane A2/prostacyclin disbalance and plasma beta-thromboglobulin changes. Both drugs prevented development of diabetic angiopathy in rats by inhibition of lipid peroxidation, prostanoid synthesis and platelet activity, but the effect of flunarizine was more pronounced, which could be explained by its additional blocking effect of abnormal calcium flux into vascular cells. The free radical scavenging action of flunarizine and aligeron was investigated.

Effect of nicergoline on learning and memory

The anti-amnestic action of nicergoline was studied using the following experimental methods for learning and memory impairment, based on passive avoidance response: amnesia induced by maximal electroshock in mice, scopolamine-induced amnesia in mice and amnesia by paradoxical sleep deprivation in rats. Piracetam, meclofenoxate, pyritinol, deanol and phenazepam were used as reference drugs. The results show that nicergoline demonstrates well-expressed anti-amnestic effect manifested by reducing the amnestic effect of maximal electroshock, scopolamine or paradoxical sleep deprivation, its effect being equal to or more pronounced than piracetam, meclofenoxate, pyritinol, deanol and phenazepam.

Effect of piracetam on the electrocorticogram after traumatic brain oedema in cats

The effect of piracetam on the electrocorticogram changes caused by experimentally-induced traumatic brain oedema in cats has been studied. The trauma was evoked by sticking a needle through the parietal associative cortical area. The electrocorticogram amplitude and frequency depression of the injured cortical area was eliminated and the bioelectrical activity restored to a normal pattern 22.4 +/- 10.3 min after a single dose of piracetam (100 mg/kg i.v.). The results indicate that piracetam recovered the cortical bioelectrical activity disturbed by experimentally-induced traumatic oedema. The beneficial effect of piracetam is probably due to an optimization of the functional state of the brain since piracetam acts as a nonspecific activator of brain excitability.

Antagonistic activity of aligeron and papaverine against different smooth muscle stimuli

The antagonistic action of aligeron as compared to that of papaverine against different smooth muscle stimuli was studied in experiments in vitro. Three series of experiments were conducted: study of the antagonistic action against experimental spasms of isolated organs caused by different spasmogens; determination of the type of antagonism to adrenaline in isolated vas deferens preparation; and study of the antagonistic action against vasoconstrictor effects of noradrenaline and adrenaline in isolated perfused rabbit renal artery. Aligeron showed a broad spectrum of antagonistic action against different spasmogens in different isolated organs. Its effect was more pronounced than that of papaverine. The antagonism was of the non-competitive type. The experiments on isolated perfused rabbit artery showed the antagonistic action of aligeron against the vasoconstrictor effects of noradrenaline and adrenaline. The results suggest the clinical use of aligeron in conditions associated with increased release of these vasoactive substances.

Anti-hypoxic effect of centrally and systemically administered prostacyclin (PGI2)

Prostacyclin (PGI2) induced a dose-dependent prolongation of survival time of mice subjected to hypoxic and anoxic hypoxia, when administered either intracerebroventricularly (i.c.v., 0.001-10 micrograms/mouse), intravenously (i.v., 0.5-500 micrograms/kg) or intraperitoneally (i.p., 50-500 micrograms/kg). The effects of a single dose of 50 micrograms/kg i.v. or i.p. and of 1 microgram/mouse i.c.v. persisted for about 30 min. The anti-hypoxic effect of PGI2 is most likely due to an action upon the CNS.

Inhibition of phospholipase A2 in vitro by some anti-hypoxic drugs

The effect of the anti-hypoxic drugs piracetam, nicergoline, papaverine, cinnarizine and aligeron on the activity of bee venom phospholipase A2 was studied in experiments in vitro. The pH-stat titration method of Grossmann et al. was used. All the drugs studied inhibited to a various degree the activity of phospholipase A2 in vitro. The most potent drug was nicergoline and the least potent was papaverine. Taking into account that the activity of phospholipase A2 is stimulated in hypoxia, the results make us believe that the inhibition of phospholipase A2 might play a certain role in the anti-hypoxic effect of the drugs studied.

Anti-hypoxic effect of piracetam and its interaction with prostacyclin

The anti-hypoxic effect of piracetam was studied using the following experimental methods: hypobaric and anoxic hypoxia in mice, complete ischemia by decapitation in mice, incomplete ischemia by bilateral carotid occlusion in rats and hemic hypoxia in rats. Cinnarizine and vinpocetine were used as reference drugs. In hypobaric hypoxia, anoxic hypoxia, and complete ischemia by decapitation the interaction of piracetam with the effect of prostacyclin (PGI2) was investigated. Piracetam showed anti-hypoxic effect in all the methods used. Its effect was greater than that of cinnarizine and similar to that of vinpocetine. Piracetam potentiated the effect of PGI2 shifting the anti-hypoxic dose-response curve of PGI2 to the left.

Arachidonic acid cascade and anti-hypoxic drugs

The anti-hypoxic effect of drugs that inhibit different steps of arachidonic acid metabolism was studied using an experimental model of acute hypobaric hypoxia in mice. The drugs investigated were chloroquine, betamethasone, chlorpromazine (phospholipase A2 inhibitors), ketoprofen (cyclo-oxygenase inhibitor) and imidazole (TxA2 synthetase inhibitor). Prostacyclin (PGI2) and PGF2 alpha were also studied. The results show that all the inhibitors of arachidonic acid metabolism manifest an anti-hypoxic effect of a various degree. PGF2 alpha had a deleterious effect, and PGI2 showed a marked anti-hypoxic effect. The results suggest that it is advantageous to search for anti-hypoxic drugs among the blockers of arachidonic acid cascade.

Study on the anti-hypoxic effect of cinnarizine and its interaction with prostacyclin

The anti-hypoxic effect of cinnarizine was studied using the following experimental methods: hypobaric and anoxic hypoxia in mice, complete ischemia by decapitation in mice and hemic hypoxia in rats. Papaverine, xanthinol nicotinate and naftidrofuryl were used as reference drugs. In hypobaric and anoxic hypoxia the interaction of cinnarizine with the effect of prostacyclin (PGI2) was investigated. Cinnarizine showed an anti-hypoxic effect in all the methods used. It was more effective in hypobaric and anoxic hypoxia, in incomplete ischemia by decapitation, and less effective in hemic hypoxia. Cinnarizine potentiated the effect of PGI2 shifting the anti-hypoxic dose-response curve of PGI2 to the left. Suggestions as to the possible mechanism of anti-hypoxic action of cinnarizine are made.

Piracetam and brain excitability. An electrophysiological study in cats

The effect of piracetam on the excitability of the brain has been examined in cats by electrophysiological approaches: spontaneous electrocorticogram (ECoG), visual evoked potentials (VEPs) and their recovery cycles in some brain structures (visual and associative cortex, lateral geniculate body, centrum medianum thalami and mesencephalic reticular formation). Piracetam (100 mg/kg i.v.) increased the spectral power of ECoG and particularly in the associative cortex for the frequency bands of 10-12 and 19-22 Hz. Piracetam decreased the early components and facilitated the late components of VEPs predominantly in the associative cortex. Changes were found in the recovery cycles too, namely, facilitation and shortening of recovery in all structures studied except in lateral geniculate body. The data suggest that piracetam acts as a non-specific activator on the excitability thus optimizing the functional state of the brain.

Anti-hypoxic effect of indomethacin and its interaction with prostacyclin

The anti-hypoxic effect of indomethacin (1-10 mg/kg) was studied using the following experimental methods: asphyxic anoxia in cats, hypobaric and anoxic hypoxia in mice, incomplete ischemia by bilateral carotid occlusion and hemic hypoxia in rats. In hypobaric and anoxic hypoxia the interaction of indomethacin with the effect of prostacyclin (PCl2) was investigated. Indomethacin showed an anti-hypoxic effect in all the methods used: it enhanced anoxia resistance index in asphyxic anoxia and significantly increased survival of rats and mice subjected to experimental hypoxia. Indomethacin potentiated the effect of PGl2, shifting the anti-hypoxic dose-response curve of PGl2 to the left. The possible mechanism of action of indomethacin in relation to cyclo-oxygenase inhibition is discussed.

Study on the anti-hypoxic effect of some drugs used in the pharmacotherapy of cerebrovascular disease

The anti-hypoxic effect of some agents used in the pharmacotherapy of cerebrovascular disease was studied using the following methods: incomplete ischemia by bilateral carotid ligation in rats, anoxic hypoxia by inhalation of argon in mice, and hemic hypoxia induced by injection of sodium nitrite (120 mg/kg s.c.) in rats. The following drugs were studied: piracetam, orotic acid, centrophenoxine, pentobarbital, vincamine, vinpocetine, cinnarizine, aligeron, xanthinol nicotinate and papaverine. The most pronounced anti-hypoxic effect was shown primarily with the metabolic acting drugs, such as orotic acid, centrophenoxine, piracetam and pentobarbital, followed by the preparations with combined metabolic and vasoactive properties (vincamine and vinpocetine). The predominantly vasoactive drugs were less effective in anoxic hypoxia, but showed more pronounced effect in incomplete ischemia.

Effect of prostacyclin (PGI2) on the mechanical activity of isolated longitudinal and circular muscle strips of guinea-pig stomach

Muscle strips isolated in longitudinal and circular directions from the fundus, corpus and antrum, and from the pyloric sphincter of the guinea-pig stomach were placed in organ baths for recording their spontaneous contractility. Concentrations of the order of 10(-9) to 10(-6) M of prostacyclin (PGI2) were tested and compared with the effect of PGE1, PGE2, PGF2 alpha and acetylcholine. Furthermore, a modification of PGI2 effect was studied in the presence of adrenergic and cholinergic blocking agents, tetrodotoxin, indomethacin and the PG antagonist SC-19220. Like PGE1, PGE2, PGF2 alpha and acetylcholine, PGI2 increased the tone of the longitudinal strips from fundus, corpus and antrum, its effect being less potent than the effects of PGE1 and PGE2 and more potent than the effects of PGF2 alpha and acetylcholine. All the PGs inhibited the phasic contractions of the circular muscle of antrum and pyloric sphincter in a dose-dependent manner. These effects were not significantly changed in the presence of adrenergic and cholinergic blocking agents, nor in the presence of tetrodotoxin, and could therefore be interpreted as being myogenic in nature. Indomethacin exerted effects opposite to those of PGI2. It shifted the log concentration-effect curve for PGI2 to the right suppressing the maximum response of PGI2 by about 50%. SC-19220 reversibly inhibited the spontaneous tone and the excitatory responses of the gastric muscle to PGI2. The concentration-effect curves for PGI2 were shifted to the right in the presence of SC-19220. Analysis of the data gave the pA2 value for PGI2 5.3, the slope of Schild plot being 1.23, which suggests that SC-19220 is a competitive antagonist.

Effect of piracetam in some models of general and local depression of the cortical bioelectrical activity in cats

The effect of piracetam (100 mg/kg i.v.) on general and local depression of the cortical bioelectrical activity was studied in acute experiments on cats. Asphyxic anoxia and hypoventilation hypoxia were used as models of general depression. Local depressions were caused by topical application of potassium chloride (KCl), adenosine monophosphate (AMP) and pentobarbital on the cortex. In the models of general depression piracetam increased cortical resistance to hypoxia and accelerated the recovery of the cortical bioelectrical activity. In KCl- and AMP-induced depressions piracetam diminished their degree and duration and completely protected the cortex against pentobarbital-caused depression.

1,4-Benzodiazepines. VIII - Central depressive activity and spasmolytic action of isoquino-[2,1-d] [1,4] benzodiazepines. Structure-activity relationships

The pharmacological activity of four new groups of isoquino [2,1-d] ((1,4]benzodiazepines, i.e. the 6-oxo-12,13-dimethoxy-5H-7H--9,10-dihydroisoquino [2,1-d] [1,4]benzodiazepinium bromides (I); 5,9,10,14b--tetrahydroisoquino [2,1-d] [1,4]benzodiazepin-7H-6-ones (II); 6-phenyl-12,13--dimethoxy-7,9,10,14b-tetrahydroisoquino [2,1-d] [1,4]benzodiazepines (III) and 6-phenyl-12,13-dimethoxy-7H-9,10-dihydroisoquino [2,1-d] [1,4]benzodiazepinium bromides (IV) was studied. All the compounds studied are biologically active. They show a depressive effect on the central nervous system, which is most pronounced in (II). It was established that the presence of alkyl substituents in the position-7 of the structure (II) as well as the chlorine atom in position-2 resulted in an increase of activity. Most of these compounds possess a mild or strong antinociceptive effect. Some of them exhibited an antireserpine activity as well. The spasmolytic effect of (IV) was strong while the rest of the compounds exerted a very weak spasmolytic effect. All the compounds tested on the autonomous nervous system possess the characteristics of weak sympathomimetics.

Study on the prostaglandin antagonistic activity of aligeron and piracetam

The interaction of aligeron and piracetam with the effects of prostaglandin F2 alpha (PGF2 alpha) E2 (PGE2) was studied using in vitro and in vivo tests for evaluation of PG antagonistic activity. Aligeron was found to be a non-selective PG antagonist in isolated guinea-pig stomach smooth muscle preparations. It antagonized the PGF2 alpha and PGE2-induced fall in blood pressure in cats prevented diarrhoea induced by PGF2 alpha in mice, inhibited rat paw oedema induced by PGE2 in rats, but did not modify the PGF2 alpha induced bronchoconstriction in guinea-pigs. Piracetam did not antagonize the smooth muscle contractile effects of PGF2 alpha and PGE2 and in the in vivo tests it inhibited only the rat paw oedema induced by PGE2. It is concluded that aligeron is active in vitro and in vivo as an antagonist of some of the actions of PGs studied. Its effect in vitro lacks selectivity and is probably due to interference with the action of Ca2+. The probable clinical implication of these results will be discussed. Piracetam can not be considered a PG antagonist.

Protective effect of piracetam against PGF2 alpha-impaired cerebral resistance to hypoxia

The protective effect of piracetam against PGF2 alpha-impaired cerebral resistance to hypoxia was investigated by EEG study in relaxed and artificially ventilated cats. Asphyxic anoxia was performed after 5 min of intracarotid (i.c.) or i.v. infusion of 10 micrograms/kg/min PGF2 alpha before and 30 min after piracetam (100 mg/kg i.v.). The following parameters were determined: cortical resistance (CRs)--as time between stopping the ventilation and the extinction of EEG; cortical recovery (CRc) - as time between restitution of ventilation and reappearance of brain activity; anoxia resistance index (ARI) - as the ratio between these two parameters (CRs/Crc). Both the i.c. and i.v. infusion of PGF2 alpha led to a significant decrease in CRs and lengthening of CRc which resulted in a decrease in ARI. Piracetam reverses the PGF2 alpha-induced changes in asphyxic anoxia. The possible mechanism of piracetam's effect and the probable therapeutic value of the latter are considered.

Effect of prostaglandin F2 alpha and prostacyclin on asphyxic anoxia in cats

The effects of exogenously applied prostaglandin F2 alpha (PGF2 alpha) and prostacyclin (PGI2) on asphyxic anoxia was studied in curarized and artificially ventilated cats. Anoxia was induced by stopping the ventilation and checking the changes in the EcoG. Cortical resistance (CRs) was evaluated as time between stopping the ventilation and the extinction of ECoG. Cortical recovery (CRc) was expressed as time between restitution of ventilation and reappearance of brain activity. Anoxia resistance index (ARI) was defined as the ratio between these two parameters (CRs/CRc). PGF2 alpha was applied by 5 minute i.v. and intracarotid (i.c.) infusion in a dose of 10 micrograms/kg/min, and PGI2 in a dose of 250 ng/kg/min for 15 minutes intracarotidly. The results show that both the i.c. and i.v. infusion with PGF2 alpha led to a significant decrease of CRs and prolongation of CRc resulting in decrease of ARI. The changes are more expressed at i.v. infusion, PGI2 does not improve the ECoG changes evoked by hypoxia. Suggestions for the possible mechanism of PGF2 alpha action and for the failure of PGI2 to protect the brain are made.

Effect of aligeron on the cerebral venous outflow and cerebrospinal fluid pressure in dogs

The effect of Aligeron (1-benzhydril-4-allyl-piperazine dihydrochloride) on the cranial circulation was studied in dogs under chloralose-urethan anaesthesia. The parameters followed were: venous outflow from the confluence of the cerebral sinusses (CVO), cerebrospinal fluid pressure in cysterna magna (CSFP), systemic arterial blood pressure (BP) and pulse rate (PR). CVP was measured using the technique of Rapela and Green (1964). Aligeron was applied at doses of 5 and 10 mg/kg i.v. Papaverine hydrochloride was used as a reference compound. aligeron administration at a dose of 5 mg/kg led to quick increase of the CVO with a duration of the effect approximately 30 min. CSFP also increased in a similar way. BP and PR showed insignificant changes. The administration of 10 mg/kg did not lead to an increase of its effect on CVO. Papaverine (1 mg/kg i.v.) had a weaker effect than that of Aligeron. According to the classical concepts the changes observed in our experiments were due to the cerebral vasodilator effect of Aligeron which caused a fall in cerebrovascular resistance and an increase of the intracranial blood volume. Our experiments suggest that Aligeron influenced the resistance vessels more than the capacitance ones.

Experimental rheoencephalographic and electroencephalographic investigations on piracetam

The influence of piracetam (2-oxo-1-pyrrolidine-acetamide, Pyramem) on the cerebral circulation and brain bioelectrical activity of cortex and mesencephalic reticular formation (RF) was studied in acute experiments on cats which were encéphale isolé preparations. The methods of local cerebral rheoencephalography (REG) and electroencephalography (EEG) were used. The following REG parameters were assayed: anacrotic section of the curve and its relative part, amplitude and duration of the wave. The arterial blood pressure was followed continuously. The results show that upon piracetam administration (150 mg/kg i.v.) an improvement of the REG parameters of the cortex and RF is observed-an increase of the amplitude and decrease of the values of the anacrotic section of the curve and its relative part. The changes observed indicate a cerebro-vascular resistance decrease and give indirect evidence of cerebral blood volume increase. EEG data are characterized mainly by an increase of alpha-waves, both of cortex and RF. Suggestions for possible mechanism of action of piracetam are made.