Effect of vitamin preparations on epileptic activity

It has been shown in experiments on mice and rats that daily administration of subthreshold doses of pentylenetetrazol led to a progressive increase in the sensitivity to the action of the epileptogen, augmentation of brain epileptization and development of the pharmacological kindling. Single administration of nicotinamide in doses of 250, 500 and 1000 mg/kg and alpha-tocopherol in a dose of 100 mg/kg exerted a pronounced antiepileptic effect under the conditions of over kindling. On combined use of nicotinamide and pyridoxal-5-phosphate, nicotinamide, pyridoxal-5-phosphate and alpha-tocopherol the antiepileptic action was more demonstrable. Daily administration of a complex of the drugs (nicotinamide, pyridoxal-5-phosphate, alpha-tocopherol) produced a substantial reduction in epileptic activity under the conditions of overt kindling. The possibility has been demonstrated of preventing the development of epileptic activity with nicotinamide under kindling.     

Effect of pantogam, nicotinamide, and phenazepam on seizure activity

Effects of different doses of nicotinamide, pantogam, pnenazepam, and their combined actions on generalized seizures induced by pentylenetetrazole (60-100 mg/kg) were studied in acute experiments on mice. It was shown that pantogam (500 mg/kg) doubled the latent period of seizures, considerably attenuated the intensity of attacks and lethality, whereas given in a dose of 1000 mg/kg it completely prevented the animals' death. Nicotinamide (250-500 mg/kg) increased the latent period of seizures without affecting the intensity of seizures or lethality. Nicotinamide (1000 mg/kg) prevented the development of clonico-tonic attacks and lethality. The antiseizure effects of nicotinamide depended on the time of its injection. Phenazepam (1.4 mg/kg) abolished seizures and in a dose of 0.1-0.7 mg/kg protected the animals from death and considerably relieved seizure manifestations. During combined injections of these compounds, the antiseizure effect was more pronounced and could be attained by decreasing the drug doses.     

Studies on lidocaine-induced kindling.

Lidocaine HCl, injected 5 times weekly, produces pharmacological kindling in rats. The aims of the present study were to: 1) approximate the threshold dose for the effect in mice and 2) determine if injections given less frequently than 5 times weekly produces kindling. Mice were injected (IP) either 5 times weekly for 4 weeks or 2 times weekly for 10 weeks, with doses ranging from 30 to 50 mg/kg. Kindling was defined as the appearance of convulsions on each of 5 consecutive injections. The estimated threshold dose for kindling was approximately 40 mg/kg, as suggested by the observation that 2 of 8 and 8 of 8 mice were kindled at 40 and 50 mg/kg respectively when injected 5 times each week. Whether mice were injected (50 mg/kg) 5 times weekly, or, only twice weekly, 80% of them were kindled by the fifteenth injection. Thus, it would appear that pharmacological kindling might be as much a function of number of injections as it is of frequency of injections.     

Verapamil contributes to the clastogenic effects of acrylamide, cyclophosphamide, and dioxidine on somatic cells of BALB/C and C57BL/6 mice

The chromosome aberration assay of metaphase bone marrow cells was used to study the clastogenic effects of acrylamide, cyclophosphamide, dioxidine, and their combinations with Verapamil (a calcium antagonist) in male BALB/C and C57BL/6 mice. Verapamil gavage at single (5 mg/kg) and repeated doses (2.5 and 5 mg/kg five times at 24-h intervals) significantly enhanced the clastogenic activity of acrylamide (50 and 100 mg/kg intraperitoneally) in BALB/C mice; in C57BL/6 mice, this effect was only observed when they received Verapamil at doses of 2.5 mg/kg for 5 days. Verapamil administered repeatedly (2.5–10 mg, gavage) significantly increased the clastogenic activity of cyclophosphamide (10 mg/kg intraperitoneally) in C57BL/6 mice. In BALB/C mice, this effect of Verapamil was only observed at a dose of 10 mg/kg (gavage). When injected intraperitoneally at a single dose of 0.1–0.4 mg/kg, Verapamil significantly enhanced the clastogenic activity of cyclophosphamide in mice of both strains. This calcium antagonist produced identical effects when administered to BALB/C mice intraperitoneally (2.5 and 5 mg/kg) and by gavage (5 mg/kg) and to C57BL/6 mice intraperitoneally (5 and 10 mg/kg) and by gavage (2.5 mg/kg). Repeated administration of Verapamil (at all doses tested) promoted the clastogenic effect of dioxidine (100 mg/kg intraperitoneally) on C57BL/6 mice, having no such influence on BALB/C mice. These results demonstrate the co-clastogenic activity of Verapamil in mice and suggest that its specific manifestations depend on the dose, method, and route of drug administration and the genotype of test animals.     

Verapamil contributes to the clastogenic effects of acrylamide, cyclophosphamide, and dioxidine on somatic cells of BALB/C and C57BL/6 mice

The chromosome aberration assay of metaphase bone marrow cells was used to study the clastogenic effects of acrylamide, cyclophosphamide, dioxidine, and their combinations with Verapamil (a calcium antagonist) in male BALB/C and C57BL/6 mice. Verapamil gavage at single (5 mg/kg) and repeated doses (2.5 and 5 mg/kg five times at 24-h intervals) significantly enhanced the clastogenic activity of acrylamide (50 and 100 mg/kg intraperitoneally) in BALB/C mice; in C57BL/6 mice, this effect was only observed when they received Verapamil at doses of 2.5 mg/kg for 5 days. Verapamil administered repeatedly (2.5-10 mg, gavage) significantly increased the clastogenic activity of cyclophosphamide (10 mg/kg intraperitoneally) in C57BL/6 mice. In BALB/C mice, this effect of Verapamil was only observed at a dose of 10 mg/kg (gavage). When injected intraperitoneally at a single dose of 0.1-0.4 mg/kg, Verapamil significantly enhanced the clastogenic activity of cyclophosphamide in mice of both strains. This calcium antagonist produced identical effects when administered to BALB/C mice intraperitoneally (2.5 and 5 mg/kg) and by gavage (5 mg/kg) and to C57BL/6 mice intraperitoneally (5 and 10 mg/kg) and by gavage (2.5 mg/kg). Repeated administration of Verapamil (at all doses tested) promoted the clastogenic effect of dioxidine (100 mg/kg intraperitoneally) on C57BL/6 mice, having no such influence on BALB/C mice. These results demonstrate the co-clastogenic activity of Verapamil in mice and suggest that its specific manifestations depend on the dose, method, and route of drug administration and the genotype of test animals.     

Changes of the dehydrogenase activity in the hippocampus in the korazol-induced kindling phenomenon

The activity of glutamate, succinate, malate and lactate dehydrogenases in neuronal and glial hippocampal cells during corazol kindling has been cytophotometrically assessed in the experiments on (CBA X C57BL/6)F1 mice. The kindling was induced by regular intraperitoneal corazol injections in subliminal dose of 30 mg/kg. Histochemical investigations were performed 30 min, 24 hours and 30 days after the corazol injections were discontinued. The changes in the enzymatic activity revealed suggest the biphasic nature of the disturbances in energy metabolism. During the first phase (24 hours after the last injection) the enzymatic changes do not have a noticeable influence on the predominant aerobic type of oxidation. In the second phase (30 days after the last injection) lactate dehydrogenase activity significantly increases, while the activity of other enzymes under study reduces.     

Effect of a combination of mild-temperature hyperthermia and nicotinamide on the radiation response of experimental tumors

Ogawa, A., Griffin, R. J. and Song, C. W. Effect of a Combination of Mild-Temperature Hyperthermia and Nicotinamide on the Radiation Response of Experimental Tumors. The effect of mild-temperature hyperthermia and nicotinamide individually or combined on tumor radiosensitivity was investigated with SCK tumors grown s.c. in the right hind limbs of A/J mice. An i.p. injection of nicotinamide at 50-250 mg/kg slightly enhanced the cell killing caused by 10-20 Gy of ionizing radiation as determined by the in vivo/in vitro tumor excision assay. Treatment of tumors with mild-temperature hyperthermia at 41.5 degrees C for 60 min prior to tumor irradiation was significantly more effective than nicotinamide and the combination of nicotinamide and hyperthermia was far more effective than nicotinamide or hyperthermia alone in enhancing radiation-induced cell killing. Radiation-induced tumor growth delay was enhanced by a factor of 1.2 by 50 mg/kg nicotinamide, 2.1 by hyperthermia, and 3.6 by the combination of nicotinamide and hyperthermia. Taking these results and those of our previous studies together, we conclude that mild-temperature hyperthermia increases tumor blood flow and oxygenation and that combining mild-temperature hyperthermia and nicotinamide is more effective than either of these alone in increasing tumor radiosensitivity.     

Influence of ginger rhizome (Zingiber officinale Rosc) on survival, glutathione and lipid peroxidation in mice after whole-body exposure to gamma radiation

The radioprotective effect of the hydroalcoholic extract of ginger rhizome, Zingiber officinale (ZOE), was studied. Mice were given 10 mg/kg ZOE intraperitoneally once daily for five consecutive days before exposure to 6-12 Gy of gamma radiation and were monitored daily up to 30 days postirradiation for the development of symptoms of radiation sickness and mortality. Pretreatment of mice with ZOE reduced the severity of radiation sickness and the mortality at all doses. The ZOE treatment protected mice from GI syndrome as well as bone marrow syndrome. The dose reduction factor for ZOE was found to be 1.15. The optimum protective dose of 10 mg/kg ZOE was 1/50 of the LD50 (500 mg/kg). Irradiation of the animals resulted in a dose-dependent elevation in the lipid peroxidation and depletion of GSH on day 31 postirradiation; both effects were lessened by pretreatment with ZOE. ZOE also had a dose-dependent antimicrobial activity against Pseudomonas aeruginosa, Salmonella typhimurium, Escherichia coli and Candida albicans.     

Effect of sesamol on radiation-induced cytotoxicity in Swiss albino mice

The radio-protective ability of sesamol (SM) at various doses viz., 0, 10, 25, 40, 50, 70 and 100mg/kg bw, administered intraperitoneally 30min prior to 9.5Gy whole-body gamma-irradiation was studied in Swiss albino mice. Radiation toxicity and mortality were observed during a period of 30 days and the percentage mortality was calculated. SM pretreatment with 50mg/kg bw was found to be the most effective dose in maintaining body weight and in reducing the percentage mortality, while 100mg/kg bw was found to be more effective in maintaining the spleen index and in stimulation of endogenous spleen colony-forming units. Pretreatment with SM (50mg/kg bw) in mice irradiated with 15Gy significantly reduced dead, inflammatory, mitotic and goblet cells in irradiated jejunum. SM at 50mg/kg bw also increased crypt cells, maintained villus height, and prevented mucosal erosion. Nuclear enlargement in epithelial cells was found less in SM-treated mice compared with the irradiated control. The radiation-induced decrease in endogenous antioxidant enzymes (GSH, GST, catalase) and the increase in lipid peroxidation were also reduced by pretreatment with SM [50 and 100mg/kg bw] at all monitored post-irradiation intervals. There was no protection at a dose less than 25mg/kg bw.     

Inhibiting effects of nicotinamide on urethane-induced malformations and tumors in mice

The antipellagratic vitamin, nicotinamide, significantly suppressed urethane-induced malformations, when it was given intraperitoneally to pregnant JCL:ICR mice immediately after a single subcutaneous injection of urethane (1.0 mg/g) on the 9th day of gestation. The level of inhibition increased with the doses of nicotinamide: 33.0, 55.8, and 70.0% at doses of 0.1, 0.3, and 0.5 mg/g, respectively. Polydactyly and tail anomalies were markedly suppressed by the post-treatment with nicotinamide, while cleft palates were less effectively suppressed. Nicotinamide was still effective, when it was given during the period of 24-48 h after urethane treatment. Furthermore, dietary administration of nicotinamide also reduced urethane-induced malformations. The level of inhibition was 39.4 and 61.1% at 0.5 and 1.0% of nicotinamide in the diet, respectively. Higher doses of nicotinamide (3 and 5% in diet) also inhibited urethane-induced malformations, but not so effectively as lower doses. The inhibiting effects of nicotinamide on the spontaneous incidence of cleft lips and palates in CL/Fr mice were significant at a low dose (0.5% in diet), but not at a higher dose (1.0%). When [carbonyl-14C]nicotinamide was given to pregnant mice, nicotinamide and small amounts of nicotinamide adenine dinucleotide (NAD+), but not nicotinic acid, were detected chromatographically in the fetus and placenta, indicating that nicotinamide or NAD+ acts directly on the fetus to suppress urethane-induced malformations. A preliminary study revealed that urethane-induced lung tumorigenesis in JCL:ICR mice was also inhibited by post-treatment with nicotinamide in the diet. The level of inhibition was proportional to the dose of nicotinamide, that is, 35.0 and 62.8% at 1.0 and 2.5% of nicotinamide in the diet, respectively.     

Effect of Different Gentamicin Dose on the Plasticity of the Ribbon Synapses in Cochlear Inner Hair Cells of C57BL/6J Mice

Faithful information transfer at the hair cell afferent synapse requires synaptic transmission to be both reliable and temporally precise. The release of neurotransmitter must exhibit both rapid on and off kinetics to accurately follow acoustic stimuli with a periodicity of 1?ms or less. To ensure such remarkable temporal fidelity, the cochlear hair cell afferent synapse undoubtedly relies on unique cellular and molecular specializations. To study effects of different doses of gentamicin on the changes of synaptic ribbons of cochlear inner hair cells (IHCs) in mice, the availability of genetic information, transgenic and knock-out animals make the C57BL/6J mouse a primary model in biomedical research. Aminoglycoside ototoxicity, however, has rarely been studied in mature mice because they are considered highly resistant to the drugs. This study presents models for gentamicin ototoxicity in adult C57BL/6J mouse strains. Five-week-old mice were injected intraperitoneally once daily with 50?C300?mg gentamicin base/kg body weight for 7?days. Higher doses of gentamicin appear to be associated with earlier hearing damage in C57BL/6J mice, although not necessarily with more severe damage. At 200?mg/kg, gentamicin appears to induce significant hearing damage while not significantly affect the animal??s general condition. Therefore, 200?mg/kg may be an ideal dose for ototoxicity modeling in C57BL/6J mice using gentamicin. In the early period of different dose of gentamicin effect, when the number of hair cells had not changed, the number changes of IHC ribbon synapses had taken place. Through the number of ribbon synapses changing, IHCs increased or decreased connections with spiral ganglion nerves (SGNs). The ribbon synapses played a compensatory role for gentamicin ototoxicity, while this effect was not sufficient to maintain the normal threshold of hearing.     

Mutagenic action of cadmium on the sex cells of male mice

Possible mutagenic effect of cadmium chloride was studied by determining the frequency of dominant lethal mutations induced in germ cells of male mice. Water solution of CdCl2 was injected intraperitoneally to male mice at doses of 1.0, 2.0 and 4.0 mg/kg. The results obtained did not reveal any mutagenic effect of this compound. The dose of 4.0 mg/kg CdCl2 resulted in the death of spermatocytes and spermatogonia and the sterility of male mice. Cadmium chloride at a dose of 2.0 mg/kg did not affect the frequency of dominant lethal mutation induced by gamma-rays 60Co at a dose of 450 r in germ cells of male mice.     

Novel nicotinamide analog as inhibitor of nicotinamide N-methyltransferase

Nicotinamide N-methyltransferase (NNMT) has been linked to obesity and diabetes. We have identified a novel nicotinamide (NA) analog, compound 12 that inhibited NNMT enzymatic activity and reduced the formation of 1-methyl-nicotinamide (MNA), the primary metabolite of NA by ～80% at 2?h when dosed in mice orally at 50?mg/kg.     

Effects of organic calcium antagonists and magnesium on the development of corazol kindling

In experiments on rats it was shown that i.p. administration of finoptin (verapamil), magnesium sulfate or ryodipine (an 1,4-dihydropyridine) 15 min before each daily injection of pentylenetetrazole (PTZ) in a subconvulsive dose (30 mg/kg i.p.) significantly (for 10-12 days delayed the development of pentylenetetrazole-induced kindling and attenuated kindled seizure reaction as compared with the controls. In animals sensitive to PTZ which were selected on the test of their reaction to previous single PTZ injection in a dose of 40 mg/kg finoptin, magnesium or finoptin + magnesium resulted in suppression of kindling development at late stages (after 2-week administration of drugs together with PTZ). After the withdrawal of the drugs there was a tendency to an increase of seizure reaction to the testing PTZ dose (30 mg/kg). The enhanced seizure susceptibility to test PTZ dose has being persisted during all observation period (8 months). Finoptin administered 15 min prior to PTZ had no effect on the severity of seizure reaction of fully kindled animals which had not received the drugs. The results obtained show that organic Ca-antagonists and magnesium delay the development of kindling induced seizure susceptibility, but cannot completely prevent it. The results also suggest that mechanisms of the chronic epileptogenesis (development of kindling induced seizure susceptibility) and those of the acute convulsive reaction to the epileptogen are not similar.     

Effect of parenterally injected benzimidazole compounds on Echinococcus multilocularis and Taenia crassiceps metacestodes in laboratory animals.

In mice infected with metacestodes of Taenia crassiceps, the following compounds were at least partially effective when injected intraperitoneally at the dosage indicated: cambendazole (500 mg/kg), mebendazole (6.25 mg/kg), oxibendazole (500 mg/kg), 5-benzamido-2(4-thiazolyl)benzimidazole (500 mg/kg), 2-carboethoxyamino benzimidazole (125 mg/kg), and 2-carbomethoxyamino benzimidazole (500 mg/kg). The following were inactive at the dosage indicated: parbendazole (500 mg/kg), thiabendazole (1,000 mg/kg), and fenbendazole (1,000 mg/kg). Mebendazole, which showed some activity at 6.25 mg/kg, was highly active as a single intraperitoneal dose at 25 mg/kg. When injected subcutaneously, mebendazole was much less active than when given intraperitoneally. In mice infected with metacestodes of Echinococcus multilocularis, intraperitoneal injection of mebendazole at 75 to 150 mg/kg, daily for 3 days, was highly effective (95 to 100% reduction in cyst mass). In contrast, oral administration at 1,000 mg/kg, daily for 3 days, was only partially effective. The drug was also effective when given intraperitoneally to infected cotton rats. A water-soluble benzimidazole, carboxymethyleneamino cambendazole, was approximately 50% effective in mice when injected daily for 3 days at a dosage of 75 or 150 mg/kg. The results suggest that, in metacestode infections of medical importance, it may be possible to kill the parasite by delivering a drug to its immediate vicinity, and so to reduce the required dosage with respect to the host.     

Effect of sesamol on radiation-induced cytotoxicity in Swiss albino mice

The radio-protective ability of sesamol (SM) at various doses viz., 0, 10, 25, 40, 50, 70 and 100 mg/kg bw, administered intraperitoneally 30 min prior to 9.5 Gy whole-body γ-irradiation was studied in Swiss albino mice. Radiation toxicity and mortality were observed during a period of 30 days and the percentage mortality was calculated. SM pretreatment with 50 mg/kg bw was found to be the most effective dose in maintaining body weight and in reducing the percentage mortality, while 100 mg/kg bw was found to be more effective in maintaining the spleen index and in stimulation of endogenous spleen colony-forming units. Pretreatment with SM (50 mg/kg bw) in mice irradiated with 15 Gy significantly reduced dead, inflammatory, mitotic and goblet cells in irradiated jejunum. SM at 50 mg/kg bw also increased crypt cells, maintained villus height, and prevented mucosal erosion. Nuclear enlargement in epithelial cells was found less in SM-treated mice compared with the irradiated control. The radiation-induced decrease in endogenous antioxidant enzymes (GSH, GST, catalase) and the increase in lipid peroxidation were also reduced by pretreatment with SM [50 and 100 mg/kg bw] at all monitored post-irradiation intervals. There was no protection at a dose less than 25 mg/kg bw.     

Tremorgenic Toxin from Penicillium verruculosum

A new mycotoxin that produces severe tremors and acute toxicity when administered orally or intraperitoneally (ip) to mice and 1-day-old cockerels was obtained from a strain of Penicillium verruculosum Peyronel isolated from peanuts. The ip 50% lethal dose (LD(50)) of this tremorgen was 2.4 mg/kg in mice and 15.2 mg/kg in chickens. Orally administered LD(50) values for the toxin were 126.7 mg/kg in mice and 365.5 mg/kg in chickens. The trivial name "verruculogen" is proposed for this tremorgenic mycotoxin. Physical and chemical characteristics of the mycotoxin are described.     

Radiosensitization by nicotinamide in vivo: a greater enhancement of tumor damage compared to that of normal tissues

In this report we describe various aspects of tumor and normal tissue radiosensitization by nicotinamide. The LD50 for a single injection of nicotinamide in C3H mice was found to be 2050 mg/kg. When a large nonlethal dose (1000 mg/kg) was injected into tumor-bearing mice, peak plasma and tumor levels were reached 30-60 min after injection and decayed with a half-life of about 3 h. This dose of nicotinamide enhanced radiation-induced cell killing in three different tumor models (EMT6, Lewis Lung, and RIF-1) when injected at least 1 h before irradiation and produced enhancement ratios (ERs) of between 1.2 and 1.7. The ER in the EMT6 tumor was dependent on the dose of nicotinamide injected, but even at doses as low as 25% of the LD50 value an ER greater than 1.5 could still be observed. In two normal tissue assays (jejunum crypt cell survival and mean skin reaction) ERs of less than 1.2 were obtained. These results, and the fact that high levels can be tolerated in humans, suggest that nicotinamide, or a structurally related compound, could be a likely candidate for development in clinical trials.     

The evaluation of the radioprotective effect of Triphala (an ayurvedic rejuvenating drug) in the mice exposed to γ-radiation

The effect of 0, 5, 6.25, 10, 12.5, 20, 25, 40, 50 and 80 mg/kg b. wt. of aqueous extract of triphala (an Ayurvedic herbal medicine) administrered intraperitoneally was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of triphala consecutively for five days before irradiation delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. The highest protection against GI (gastrointestinal) death was observed for 12.5 mg/kg triphala, where a highest number of survivors were reported up to 10 days post-irradiation. While 10 mg/kg triphala i.p. provided the best protection as evidenced by the highest number of survivors after 30 days post-irradiation in this group when compared with the other doses of triphala. Toxicity study showed that triphala was non-toxic up to a dose of 240 mg/kg, where no drug-induced mortality was observed. The LD50 dose i.p. of triphala was found to be 280 mg/kg b. wt. Our study demonstrates the ability of triphala as a good radioprotective agent and the optimum protective dose of triphala was 1/28 of its LD50 dose.     

Colchicine blocks the action of parathyroid hormone but not nicotinamide on renal phosphate transport

Nicotinamide, like parathyroid hormone, is a rapidly acting specific inhibitor of Na+-dependent transport of phosphate (Pi) across the brush-border membrane of the proximal tubule of the mammalian kidney. Pretreatment of rats with colchicine (0.7 mg/kg body weight) for 1 h led to a significantly diminished phosphaturic response to parathyroid hormone (synthetic 1-34 fragment, 4 micrograms/kg). In contrast, the same dose of colchicine had no effect on the renal response to nicotinamide (1.0 g/kg), measured both as the change in urinary Pi excretion and as Na+-dependent Pi uptake by isolated brush-border membrane vesicles. These data suggest indirectly that the intracellular mechanism that mediates the inhibitory effects of nicotinamide on renal Pi transport does not require intact microtubules.