Carboxymethyl chitin-glucan enriched diet exhibits protective effects against oxidative DNA damage induced in freshly isolated rat cells.

The connection between dietary intake of carboxymethyl chitin-glucan (CM-CG, approximately 200 mg/kg body weight, during 21 days) and the response of freshly isolated rat cells to genotoxic treatment with a combination of photosensitizer Methylene Blue and visible light (MB+VL) was evaluated in presented study. Blood lymphocytes, testicular cells, and hepatocytes were isolated from rats fed by a standard or CM-CG enriched diet and in ex vivo conditions challenged with oxidative agent. Induced DNA damage was assessed using a modified comet assay. When added to the diet, CM-CG itself did not induce any negative effect on the health condition of animals or on level of DNA breaks in rat cells. Moreover, the cells isolated from CM-CG fed animals were more resistant to oxidative stress induced by visible light-excited Methylene Blue. In conclusion, we have demonstrated that carboxymethyl chitin-glucan represents a natural fungal polysaccharide that is able to exert antimutagenic properties upon application in diet.

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water.

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

Sibutramine in the treatment of obesity in type 2 diabetic patients and in nondiabetic subjects.

Obesity is considered a chronic disease requiring treatment. The effect of sibutramine combined with hypocaloric diet and exercise on body weight, body fat mass, lipids, glycemic control, insulin secretion and insulin resistance was evaluated in a randomized, controlled, open-label study. A total of 44 obese type 2 diabetic patients (aged 45.2+/-5.2 years, BMI 33.62+/-2.2 kg/m(2)) and 49 obese nondiabetic subjects (aged 41.9+/-5.7 years, BMI 34.3+/-2.6 kg/m(2)) were treated with sibutramine for 3 months. Moreover, 39 age-matched obese type 2 diabetic patients and 41 obese nondiabetic subjects only on hypocaloric diet and exercise served as control groups. Insulin secretion was estimated during intravenous glucose tolerance test; insulin resistance was assessed by the HOMA index. There was a significant reduction in body weight in both sibutramine-treated diabetic patients (7.1%) and nondiabetic subjects (9.1%), accompanied by a significant reduction in body fat mass. HbA1c decreased significantly in the diabetic patients after sibutramine treatment. There was a significant improvement of lipid parameters in the two groups. Insulin resistance decreased by 21.9% in the sibutramine-treated diabetic patients and by 38.5% in the nondiabetic group. Weight loss was accompanied by an increase of 43.8% in first phase insulin secretion in the sibutramine-treated diabetic group; in the treated nondiabetic subjects there was a decrease in first and second phase insulin secretion and the area under the curve for total insulin secretion. In conclusion, sibutramine leads to a significant reduction in body weight, body fat mass and waist and hip circumferences; it improves insulin sensitivity, insulin secretion, glycaemic control and lipid parameters in both diabetic and nondiabetic obese subjects.

Diet containing fungal (1-->3)-beta-D-glucan derivative exhibits protective effects against DNA lesions induced in freshly isolated rat cells.

Dietary effect of water-soluble derivative - carboxymethyl chitin-glucan (CM-CG) on the level of DNA lesions induced by hydrogen peroxide (H2O2) was examined in ex vivo experiments. Lymphocytes, testicular cells, alveolar macrophages and epithelial II cells were isolated from Sprague Dawley rats fed a common or CM-CG enriched diet (200 mg/kg of body weight) during 21 days. Freshly isolated cells were in in vitro conditions exposed to H2O2 and the levels of DNA breaks were evaluated by single cell gel electrophoresis. A dose-dependent increase of DNA breaks was observed after treatment with hydrogen peroxide in all studied cell types. The levels of DNA breaks in cells isolated from CM-CG supplemented animals were lower compared to the levels of DNA breaks in cells isolated from animals fed a common diet. Intake of CM-CG enriched diet did not increase the level of DNA damage in different kinds of freshly isolated rat cells and equipped the cells with resistance to the treatment with hydrogen peroxide.

Repair of oxidative DNA lesions in blood lymphocytes isolated from Sprague-Dawley rats; the influence of dietary intake of lignin.

Living organisms possess a variety of self-protective mechanisms which decrease the free radical attack on DNA and so reduce the risk of cancer. Protection of DNA by endogenous antioxidant systems may be significantly increased by numerous exogenously administered antioxidants. Many of them represent important dietary factors. Biopolymer lignin with its phenolic structure can be included into this group of micronutrients. The aim of the present work was to investigate: 1. the effect of biopolymer lignin, given to Sprague-Dawley (SD) rats in diet, on the level of oxidative DNA lesions induced by oxidative stress in freshly isolated peripheral blood lymphocytes in vitro and 2. the influence of lignin on kinetics of rejoining of DNA strand breaks induced in lymphocytes under these conditions. As model oxidative agents were used H2O2 and visible light in the presence of the photosensitizer Methylene Blue. We found out that dietary intake of lignin caused a significant decrease of H2O2-induced DNA strand breaks and visible light-induced oxidative DNA lesions in freshly isolated rat lymphocytes, but it did not influence the kinetics of rejoining of DNA strand breaks.

Involvement of nitric oxide in the nociception of kyotorphin, TYR-CAV and MIF-s analogues in the rat spinal cord.

The spinal analgesic effects of Kyotorphin (Kyo) and Melanocyte-inhibiting factor (MIF-l) were studied during acute pain in rats chronically implanted with intrathecal (i.t.) cannulas. Kyo (5 micrograms), t-Cav (5 micrograms), Tyr-Cav (5 micrograms), L-NAME (1500 micrograms), MIF-Cav (200-400 micrograms) and MIF-sLeu (200 micrograms) exerted antinociceptive effects in both tests. The coadministration of Kyo + L-NAME enhanced the nociceptive effect compared with L-NAME (PP) or Kyo alone (PP, TF). The combination of Tyr-Cav + L-NAME enhanced the antinociceptive effect compared with L-NAME (PP) or Tyr-Cav alone (TF, PP). MIF-l (200 micrograms) had a weak antinociceptive effect in both tests. The coadministration of MIF-Cav + L-NAME enhanced the nociceptive effect compared with L-NAME (TF) or MIF-Cav alone (TF). The combination of MIF-sLeu + L-NAME enhanced the antinociceptive effect compared with L-NAME (TF) or MIF-sLeu alone (TF, PP). The results suggest that nitric oxide (NO) is involved in the antinociceptive effects of neuropeptides in the rat spinal cord.

Effects of the calcium antagonists verapamil and nitrendipine on carbamazepine withdrawal.

This study was aimed at examining the effects of two frequently used Ca2+ antagonists, nitrendipine and verapamil, on withdrawal after cessation of long-term treatment with the anticonvulsant drug carbamazepine in rats. The 48-h interruption of long-term (21 days) carbamazepine treatment led to the appearance of withdrawal characterized by increases in seizure intensity, the percentage of rats with tonic seizures and mortality. Oral treatment with the two calcium antagonists in combination with carbamazepine abolished the signs of carbamazepine withdrawal. Seizure intensity, the percentage of rats with tonic seizures and mortality in the groups treated with the combinations of carbamazepine + verapamil and carbamazepine + nitrendipine were significantly lower than those of the group of rats treated with carbamazepine alone. In conclusion, some Ca2+ antagonists could attenuate the manifestations of anticonvulsant withdrawal and thus could be used as adjuvants in long-term anticonvulsant therapy.

Effects of non-peptide angiotensin II-receptor antagonists on pentylenetetrazol kindling in mice.

The effects of non-peptide AT1- and AT2-receptor antagonists DuP 753 (losartan) and PD 123319 on the intensity of pentylenetetrazol (PTZ)-kindled seizures in mice were studied. PTZ was injected intraperitoneally at a subconvulsive dose of 40 mg/kg at 48 h until the appearance of clonic seizures. DuP 753 administered intracerebroventricularly (i.c.v.) tended to decrease seizure intensity. Successive administration of ineffective doses of DuP 753 (losartan) and AT2 (angiotensin II) significantly decreased seizure intensity. PD 123319 (i.c.v.) decreased seizure intensity. Combination of ineffective doses of PD 123319 and AT2 also significantly decreased seizure intensity. The results suggest the role of AT2 receptor and its subtypes in PTZ-kindled seizures as well as an action of DuP 753 and PD 123319 similar to the action of AT2, an AT2-receptor agonist.

Effect of dotarizine on electroconvulsive shock or pentylenetetrazol-induced amnesia and on seizure reactivity in rats.

Dotarizine (DOT), a compound performing both as calcium antagonist and as 5-HT2 receptor antagonist, was evaluated for its ability to protect against electroconvulsive shock (ECS)- and pentylenetetrazol (PTZ)-induced performance deficit in a passive avoidance "step-down" task in rats. Its effect on electric and PTZ seizure models was also studied. DOT administered orally at a dose of 50 mg/kg for 5 days before learning had no significant effect on retention tests given 3 h, 24 h and 7 days after the training session. It should be noted, however, that DOT completely prevented ECS- and PTZ-induced amnesia in passive avoidance situation. DOT had a pronounced protective effect against electric seizures but did not affect PTZ seizures. The present results provide additional evidence for the role of serotonergic neurotransmitter system and calcium homeostasis for memory and seizure reactivity and may be important in the development of effective treatment strategies for memory dysfunction.

Further evidence for the interactions between angiotensin II and GABAergic transmission in pentylenetetrazol kindling seizures in mice.

The effects of the GABAergic drugs nipecotic acid, Gabrene, baclofen and metatolylcarbamide (MTC), when given alone or in combination at subthreshold doses with AT II also at a subthreshold dose effective on PTZ-kindling in mice were studied. PTZ-kindling was provoked by intraperitoneal (i.p.) injections of PTZ (40 mg/kg) every other day in male albino mice until clonic seizures appeared. Nipecotic acid (100 and 200 micrograms/mouse intracerebroventricularly [i.c.v.]) tended to decrease seizure intensity. Gabrene (25, 50, 100 and 250 mg/kg i.p.) inhibited PTZ-kindled seizures. Baclofen at a doses of 2.5 and 5 mg/kg i.p. tended to decrease seizure intensity and at a dose of 10 mg/kg was ineffective at all. MTC (50 and 75 mg/kg i.p.) tended to decrease and at a dose of 100 mg/kg significantly decreased seizure intensity. Combinations of subthreshold dose of AT II (0.05 micrograms/mouse i.c.v.) and subthreshold doses of nipecotic acid (100 micrograms/mouse) or Gabrene (10 mg/kg) or baclofen (10 mg/kg) or MTC (50 mg/kg) significantly decreased the intensity of PTZ-kindled seizures in mice. The observed potentiation of the anticonvulsive activity on PTZ-kindling suggests interactions of AT II receptors with GABA receptors (GABAA, GABAB or both), effected through allosteric mechanisms.

Effects of cytidine diphosphate choline on rats with memory deficits.

The effects of cytidine diphosphate choline (CDP-choline, CAS 987-78-0) on learning and memory in rats with memory deficits were examined using behavioral methods of active avoidance with punishment reinforcement (shuttle-box), passive avoidance with punishment reinforcement (step-through and step-down), and active avoidance with positive (alimentary) reinforcement (staircase-maze). In the majority of experiments CDP-choline was applied orally at doses of 10-50 or 100 mg/kg daily for 7 days before the training session. The experiments were carried out on young-adult (aged 5 months) and old (aged 22 months) rats and on rats with a low capability for retention of learned behavior. Memory deficits were induced by the muscarinic cholinoceptor antagonist scopolamine (in young and old rats and mice), by the alpha 2-adrenoceptor agonist clonidine, by electroconvulsive shock, and by hypoxy. Memory deficits were also induced in rats offspring of dams that had been exposed to alcohol during pregnancy and lactation. The results suggest that CDP-choline acts as a memory-enhancing drug and that its effect is particularly pronounced in animals with memory deficits.

Stimulation of 5-HT1A receptors in the dorsal hippocampus impairs acquisition and performance of a spatial task in a water maze.

8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a potent 5-HT1A receptor agonist, was infused in the dorsal hippocampus of rats and its effect on acquisition and performance of a 2-platform spatial discrimination task was studied using a water maze. The infusion (0.5 microliter/min) of 2 but not 0.4 microgram 8-OH-DPAT in the CA1 region of the dorsal hippocampus impaired rats' accuracy with no effect on latency (except day 3). At 5 micrograms 8-OH-DPAT impaired rats' accuracy and significantly increased choice latencies from day 2 to day 5 of the training period. The dose of 2 micrograms significantly increased the errors of omissions on the first day of training and animals which had received 5 micrograms 8-OH-DPAT made significantly more errors of omission on the first and second days of training. Intrahippocampal administration of 1 microgram spiroxatrine, a 5-HT1A receptor antagonist, antagonized the effect of 5 micrograms 8-OH-DPAT on accuracy and choice latency with no significant effect on the errors of omission on days 1 and 2 of training. Infusion of 2 and 5 micrograms 8-OH-DPAT in the dorsal hippocampus also impaired accuracy in well-trained rats. The results suggest that stimulation of 5-HT1A receptors in the CA1 region of the dorsal hippocampus causes an impairment of spatial discrimination in rats.

Behavioral effects of stem-leaves extract from panax ginseng C.A. Meyer.

The behavioral effects of extracts from ginseng stem and leaves (GL), standardized with respect to the total saponines, and from ginseng roots (G115), standardized with respect to the content of ginsenosides were examined in experiments on rats with undisturbed memory and in rats with experimentally-impaired memory (electroconvulsive shock) using the methods for active avoidance (shuttle-box) and passive avoidance (step-down, step-through), the water-maze method and the method for studying exploratory behavior. On multiple administration G115 exerted favorable effects on learning and memory and on the higher nervous activity as a whole. These effects greatly varied with the dose and administration schedules, with the rat strain, with the rat's ability to perform adequately in any particular learning task, and with the behavioral method. The extract from the overground part of ginseng (GL) had, in the majority of cases, an effect weaker than that of G115 or was without effect at all. Based on previous and present results, we discuss the role of the changes in brain biogenic monoamines induced by the extracts for their mechanism of action.

Interactions between angiotensin II, diazepam, clonazepam and di-n-propylacetate in pentylenetetrazol kindling seizures in mice.

The effects of AT II alone and in combinations with the anticonvulsants diazepam, clonazepam and di-n-propylacetate (depakine) on PTZ-kindling in mice were studied. PTZ-kindling was provoked by intraperitoneal (i.p.) injections of PTZ (40 mg/kg) every other day in male albino mice until clonic seizures appeared. AT II in doses 0.1 and 1 microgram/mouse intracerebronventricularly (i.c.v.) decreased the intensity of seizures in PTZ-kindled mice. Diazepam (0.25 and 1 mg/kg i.p.), clonazepam (0.05 and 0.1 mg/kg i.p.) and depakine (75 mg/kg) inhibited PTZ-kindled seizures. Combinations of ineffective doses of AT II (0.05 microgram/mouse) and ineffective doses of diazepam (0.1 mg/kg) or clonazepam (0.01 mg/kg) or depakine (50 mg/kg) significantly decreased the intensity of seizures in PTZ-kindled mice. The seizure-decreasing effect of diazepam, clonazepam and depakine on PTZ-kindling in mice, which was potentiated by AT II, suggests interactions of AT II receptors with GABA and benzodiazepine receptors or with the GABA-benzodiazepine receptor-ionophore complex, probably effectuated through alsoteric mechanisms. A more efficient coupling of the GABA-benzodiazepine receptor-ionophore complex with AT II receptors might also be the reason for the decrease of the intensity of seizures in PTZ-kindled mice.

Memory effects of a group of newly-synthesized pyrrolidine derivatives with putative nootropic effect.

The original pyrrolidine derivatives with putative nootropic effect: para-chloro-phenoxyacetyl-2-pyrrolidinone (Mf-P), 1-adamantanyl-2-pyrrolidinone (A-P), 2-oxo-1-pyrrolidine-3,7-dimethylxanthine (A-T) and para-benzoyl-1,4-dipyrrolidinone (p-P), were studied. Toxicological screening performed on mice demonstrated the low toxicity of the compounds. Five- or seven-day oral administration of the substances to rats in a dose of 100 mg/kg weight facilitated the learning process and improved the memory of the rats with most of the conditioned-reflex methods used. Application of Mf-P to 2- and 24-month-old rats for 8 days induced changes in the levels of some biogenic monoamines in the brain structures studied. The results obtained, as well as the results of other studies in this laboratory, show that the pyrrolidine derivatives studied, which can be considered to be original new aniracetam analogues, improve the memory process. This effect varies strongly depending on the regime of application of the compounds studied, on the memory capacity of the experimental animals and on the experimental method used. The changes in the brain neurotransmission induced by the substances studied play an essential role in their mechanism of action.

Comparative studies on the influence of ONK (N(5-hydroxynicotinoil) glutamic acid), piracetam and meclofenoxate on the learning- and memory-impairing effect of scopolamine, clonidine, and methergoline.

The effects of the new compound N(5-hydroxynicotinoil)glutamic acid (ONK) in comparison with the well-known nootropic drugs piracetam and meclofenoxate on cognitive functions impaired by scopolamine, clonidine or methergoline were examined in albino rats and mice. The changes in learning and memory were studied by the two-way active avoidance "shuttle-box", passive avoidance "step-down" in rats and passive avoidance "step-through" in mice. The present results showed that ONK (50 mg/kg) injected intraperitoneally (i. p.), piracetam (800 mg/kg) and meclofenoxate (100 mg/kg) administered orally once daily for 5 days before training completely antagonized the scopolamine-provoked amnesia in step-through-trained mice. ONK (50 mg/kg) administered i. p., piracetam (600 mg/kg) and meclofenoxate (100 mg/kg) administered orally once daily for 5 days before training abolished the memory-impairing effect of clonidine in shuttle-box-trained rats and the amnestic effect of methergoline in step-down trained rats. The observed antiamnestic effects of the nootropic drugs studied are probably realised through their influence on cholinergic, noradrenergic and serotoninergic neurotransmission. The favourable effect of ONK on cognition might be of interest for therapeutic practice.

Modulation of the effects on learning and memory of nootropic drugs and central stimulants when applied together.

In experiments on rats using passive avoidance with punishment reinforcement (step-through) and two-way active avoidance with punishment reinforcement (shuttle-box), we examined the effects on acquisition and retention of different combinations of the nootropic drugs meclofenoxate (Mf), citicholine (CCh), piracetam (Pc), the structural analogues of aniracetam p-P and p-F, standardized extract from ginseng roots (PG) and the psychostimulants caffeine (Caf) and amphetamine (Amph). Favorable effects (more pronounced improvement of learning and/or memory as compared to that caused by the drugs when given alone) were in some cases obtained by the combination Mf+Caf, Pc+Caf, CCh+Caf, p-F+Caf, Mf+CCh, as well as by the combination Mf+PG applied to rats with electroconvulsive shock-induced amnesia. However, in some cases the combined administration of two drugs with favorable effects on memory did not led to summation or potentiation but rather to disappearance of these effects. This was observed under certain experimental conditions with some combinations of Caf and CCh, Mf, Pc and p-P and with some combinations of Amph and Mf. Based on our earlier results and data in the literature, we present some considerations about the role of the neurotransmitter mechanisms of action of the drugs tested as neurochemical correlates of their effects on memory. It is suggested that the unfavorable results obtained in some cases with combinations of nootropics and psychostimulants are due to the possible disturbance of selective acquisition by the psychostimulant drug.

Influence of nootropic drugs on the learning- and memory-impairing effect of diethyldithiocarbamate in albino rats.

The effects of four nootropic drugs (piracetam, aniracetam, meclofenoxate and fipexide) on the impaired cognitive functions by the dopamine-beta-hydroxylase inhibitor diethyldithiocarbamate (DDC) were investigated in albino rats. The changes in learning and memory were studied by the two-way active avoidance with punishment reinforcement (shuttle box). DDC injected intraperitoneally at a dose of 300 mg/kg in the course of the 5-day shuttle box training significantly impaired learning and retention. The 10-day treatment (5 days before and 5 days during training) with piracetam 600 mg/kg, aniracetam 50 mg/kg, meclofenoxate 100 mg/kg and fipexide 10 mg/kg completely abolished the learning- and memory-impairing effect of DDC. The role of the NA-ergic neurotransmitter system for the DDC-induced disturbances in cognition as well as for the protective effects of nootropic drugs was discussed.

Effect of meclofenoxate on pentylenetetrazol kindling in albino rats.

The effects of a single and 5-day treatment of male albino rats with meclofenoxate in a dose of 100 mg/kg on the clonic-tonic convulsions during the kindling phenomenon, induced by multiple injection of a subconvulsive dose (40 mg/kg) pentylenetetrazol (PTZ) were tested. Its effects on convulsions, induced by a single convulsive dose of 100 mg/kg, were investigated for the sake of comparison. Meclofenoxate, introduced in a single dose of 100 mg/kg, lowered the intensity of the convulsions in PTZ-kindled rats. Meclofenoxate treatment for 5 days had an even more pronounced inhibitory effect on PTZ kindling. As regards the convulsions induced by a single injection of a convulsive PTZ dose, meclofenoxate only tends to decrease the percentage of rats with tonic convulsion and the lethality. On the basis of the results of earlier studies, the role of the serotoninergic neurotransmitter system for the observed inhibitory effect of meclofenoxate on PTZ kindling in albino rats is discussed.

Effects of meclofenoxate and Extr. Rhodiolae roseae L. on electroconvulsive shock-impaired learning and memory in rats.

In experiments on albino rats, the authors studied the effects of meclofenoxate and Extr. Rhodiolae roseae on the memory-impairing action of convulsant electroshock. "Step-down" passive avoidance training with negative reinforcement was used to trace the changes in memory. Meclofenoxate administered i.p. in a dose of 100 mg/kg body weight for five days prevented the retrograde amnesia observed after convulsant electroshock upon retention testing on the 3rd and 24th hr after the end of the training session. The Rhodiola extract administered orally in a dose of 0.10 ml/rat for 10 days, which in other experimental approaches improved learning and memory, remained ineffective here. The role of biogenic monoamines in the learning- and memory-improving effects of meclofenoxate is considered on the basis of earlier studies by the authors.