Subacute toxicity of Basalin in rats

Basalin, a herbicide, was administered orally to male rats at doses ranging from 60 mg to 1.92 g/kg for 13 weeks. Oral LD50 of the compound was 1.65 g/kg. Toxic effects included hyperexcitability and tremors. The cumulative lethal dose (CLD50) at the end of week 13 was 135 mg/kg with a cumulative toxicity factor (CTF) of 12.22. At 1.92 g/kg, no animals survived to 13 weeks. At 60 and 120 mg/kg, there were no significant changes in body weight gain compared with the controls and a significant decrease in total leukocyte count (TLC), erythrocyte sedimentation rate (ESR) and Hb was observed. There was a decrease in spermatogenesis and infiltration of mononucleated cells in the liver.     

Safety evaluation studies on oxisuran,a differential inhibitor of cell-mediated hypersensitivity

Preclinical toxicity studies were conducted on oxisuran, 2-[(methylsulfinyl) acetyl]-pyridine, an immunosuppressant with selective inhibition of cell-mediated hypersensitivity. Oral LD50 values were 5280 and 6610 mg/kg in female mice and rabbits, respectively, and 6550 mg/kg in female and male rats. An LD50 could not be established in dogs because of emesis at a dose of 5000 mg/kg. Intravenous LD50 values were 2510 mg/kg for mice and 1800 mg/kg for female and male rats. Feeding the drug in the diet to rats at dosages of 20, 100, 300, and 1000 mg/kg for 13 weeks caused a slight reduction in food consumption and body weight gain at the higher dosages. At doses of 100, 300, and 1000 mg/kg, cloudy swelling and fatty infiltration of the liver and hyperplasia of the thyroid occurred in dose-related patterns (mild to moderate) in many animals. No significant changes were found in thyroid function studies which included thyroid uptake (¹²⁵I) and T₃ and T₄ determinations. The thyroid hyperplasia seen at 13 weeks disappeared within a few days of drug withdrawal. Oral daily administration of 20, 125, 500, and 2000 mg/kg of oxisuran to dogs for 13 weeks produced a decrease in food consumption and body weight in the latter phase of the study in the males treated with the high dose. Serum glutamic-pyruvic transaminase was mildly elevated in dogs given 2000 mg/kg. At this dose, some animals showed slightly increased thyroid and liver weights. Histologically, thyroid hyperplasia was moderate in females (2000 mg/kg) and mild to moderate in males (125, 500, and 2000 mg/kg). The liver, in the animals of the high-dose group showed a slight degree of vacuolar changes and bile retention. Thyroidal radioiodine uptake (¹²⁵I), PBI, TI, and serum cholesterol were slightly below normal values. The histology and function tests of the thyroid were within normal ranges at 4 weeks post-treatment.     

醋氨己酸锌动物安全性评价的实验研究

醋氨己酸锌（１）小鼠ｉｖ和ｉｇ的急性ＬＤ５０分别为２４．５４ｍｇ／ｋｇ和３．６０ｇ／ｋｇ。大鼠口服９０ｄ的长期毒性实验表明，１的主要毒性靶器官是胃，可引起胃粘膜壁细胞减少或空泡变性，脾小体体积缩小，红髓内红细胞减少。这些表现与剂量有关，停药后可恢复。犬口服９０ｄ的长期毒性实验未见明显毒性。提示临床使用该药，在一定剂量范围内是安全的。     

Acute and subchronic toxicity studies of the new quinolone antibacterial agent irloxacin in rodents.

Irloxacin (6-fluorine-7-(pyrrol-1-yl)-1-ethyl-1, 4-dihydro-4-oxo-quinolone-3-carboxylic acid, CAS 91524-15-1), a new quinolone antibacterial agent, was administered as a single dose to rats and mice both by oral and intraperitoneal route in oder to study its acute toxicity. Its oral subchronic toxicity was also assessed by treating rats for 4 and 13 weeks. The results obtained showed that irloxacin was well tolerated after single administration in mice and rats, with LD50 values above 2000 and 5000 mg/kg for intraperitoneal and oral administration, respectively. In the oral subchronic toxicity studies, the histopathological examination performed after the 13-week treatment period confirmed the kidney as the target organ for toxicity. Increased presence of lipofuscin in the kidneys was observed in animals receiving 2000 or 450 mg/kg/d, and degeneration and/or dilatation of proximal renal tubules and chronic interstitial nephritis in males receiving these dosages. No histopathological findings were observed in the kidneys of animals receiving 100 mg/kg/d for 13 weeks. Other relevant findings were, presence of dark or cloudy urine with slightly lower pH in animals receiving dosages of 450 mg/kg/d and above, increased urinary protein concentration in animals receiving 2000 or 450 mg/kg/d, and increased plasma urea concentration in those receiving 2000 mg/kg/d. Moreover, increased plasma phospholipids and total cholesterol concentration, and increased liver and kidney weights were observed among treated animals. As a summary, the results have shown that irloxacin has a low acute toxicity in both mice and rats. For repeat oral administration in rats, 100 mg/kg can be considered as the non-toxic effect level after a treatment period of 13 weeks.     

The curative power of 4-(2:6-diaminopyrimidin-4-ylamino) phenylarsine oxide (compound 12,065) in infections of Trypanosoma rhodesiense in laboratory animals

The toxicity to laboratory animals of 4-(2:6-diaminopyrimidin-4-ylamino)phenylarsine oxide (compound 12,065), and its ability to cure laboratory infections of Trypanosoma rhodesiense were investigated. The intramuscular LD50 to mice was 22 mg./kg.; rats were more susceptible. Monkeys tolerated two daily doses of 6 mg./kg., but not two daily doses of 10 mg./kg. The intramuscular CD50 to mice was about 6 mg./kg. with two strains of T. rhodesiense recently isolated from human patients, and 2 mg./kg. with a strain of T. rhodesiense which had been maintained by cyclical transmission through tsetse flies in the laboratory for about 17 months. These results are compared with those reported by Ainley and Davey (1958) for a strain of T. rhodesiense which had been maintained in the laboratory by cyclical transmission for about 12 years and then by syringe transmission for about 10 years. The syringe-transmitted strain was at least 20 times more susceptible to the drug than the recently isolated strains. The potencies of compound 12,065 and melarsen oxide/BAL in curing T. rhodesiense infections in mice were compared: the CD50 for compound 12,065 was 6.5 mg./kg. and for melarsen oxide/BAL was 3.7 mg./kg. The ratios LD50/CD50 for the drugs were about 4 and 6 respectively.     

Lack of effect of single high doses of buprenorphine on arterial blood gases in the rat.

High dose buprenorphine, a potent semisynthetic agonist-antagonist for opiate receptors, is now used in substitution treatment of human heroin addiction. Deaths have been reported in addicts misusing buprenorphine. We determined the median lethal dose (LD(50)) and studied the effects of high doses of intravenous buprenorphine on arterial blood gases in rats. Male Sprague-Dawley rats were administered buprenorphine intravenously to determine the LD(50) using the up-and-down method. Subsequently, catheterized groups of 10 restrained rats received no drug, saline, acid-alcohol aqueous solvent (required to dissolve buprenorphine at a high concentration), or 3, 30, or 90 mg/kg of buprenorphine intravenously. Serial arterial blood gases were obtained over 3 h. The LD(50) determined in triplicate was 146.5 mg/kg (median of 3 series, range: 142.6-176.5). The mean dose received by surviving animals was 96.9 +/- 46.7 mg/kg. There was a significant effect of the acid-alcohol aqueous solvent on arterial blood gases. Excluding the solvent effect, 3, 30, and 90-mg/kg buprenorphine doses had no significant effects on arterial blood gases. The toxicity of intravenous buprenorphine in adult rats, assessed by the LD(50), is low. These data are consistent with a wide margin of safety of buprenorphine. The mechanism of death after the intravenous administration of a lethal dose of buprenorphine remains to be determined.     

Reproductive, acute and subacute toxicity studies with nefopam in laboratory animals.

Nefopam hydrochloride, a compound with non-narcotic analgesic activity, was evaluated for its acute and subacute toxicity in mice, rats, and dogs. Potential teratogenic effects in mice and rabbits and its effect on general reproduction and postnatal development in rats were also studied. The LD50 by various routes of administration showed that in all three species oral LD50 values (80–178 mg/kg) were greater than im LD50 values (30–57 mg/kg) which were higher than iv LD50 values (20–45 mg/kg). A comparative oral acute toxicity study did indicate a strain difference in rats. Repeated daily administration of nefopam hydrochloride to rats and dogs at doses up to 10 mg/kg/day parenterally and 80 mg/kg/day orally revealed no toxic effects except for mild tissue irritation at injection sites and slight weight loss in some dogs receiving the high dose. Reproduction studies did not reveal any effects on fertility, lactation, or pup development and viability.     

3-乙酰乌头碱的毒性和致畸性

小鼠ig 3-乙酰乌头碱的LD_(50)为3.09mg/kg,其他各种注射途径的LD_(50)在0.40-0.70mg/kg间,约为ig的13-23％;大鼠LD_(50)为小鼠的53-74％。在亚急性毒性实验中,3-乙酰乌头碱中毒剂量可致大鼠呼吸抑制而死亡,家兔除有呼吸抑制外尚出现ECG的异常。组织病理学变化主要为心肌细胞变性,肝细胞轻度损伤。阿托品加人工呼吸对3-乙酰乌头碱所致的大鼠和兔的呼吸抑制有较好的对抗效果。致畸实验未见胎仔畸形。     

苯环喹溴铵喷鼻剂的大鼠毒性作用研究

目的探讨苯环喹溴铵喷鼻剂对大鼠的急性毒性和慢性毒性作用。方法通过鼻黏膜给药,以Bliss法求出药物的半数致死量（LD50）;并以LD50的1／100,1／200,1／400作为大（3．00mg／kg）、中（1．50mg／kg）、小（0．75mg／kg）剂量,另设溶剂对照组,观察药物对大鼠的慢性毒性作用。结果大鼠鼻黏膜给药的LD50为300．38mg／kg,95％可信限为263．58～342．31mg／kg;各剂量组大鼠连续经鼻给药6个月,其一般体征、精神状态、毛发、体重、脏器系数、肾功能、肝功能、血液生化、血液学、大体解剖、组织病理学检查均未见明显毒性发生。用药期间大剂量组和中剂量组某些观察指标有些异常,但停药2周后均恢复。结论苯环喹溴铵喷鼻剂连续给药6个月,在设定剂量下,大、中剂量有一定的毒性反应出现,小剂量则无明显改变。     

The effects of repeated low-dose sarin exposure

This project assessed the effects of repeated low-dose exposure of guinea pigs to the organophosphorus nerve agent sarin. Animals were injected once a day, 5 days per week (Monday-Friday), for 2 weeks with fractions (0.3x, 0.4x, 0.5x, or 0.6x) of the established LD(50) dose of sarin (42 microg/kg, s.c.). The animals were assessed for changes in body weight, red blood cell (RBC) acetylcholinesterase (AChE) levels, neurobehavioral reactions to a functional observational battery (FOB), cortical electroencephalographic (EEG) power spectrum, and intrinsic acetylcholine (ACh) neurotransmitter (NT) regulation over the 2 weeks of sarin exposure and for up to 12 days postinjection. No guinea pig receiving 0.3, 0.4 or 0.5 x LD(50) of sarin showed signs of cortical EEG seizures despite decreases in RBC AChE levels to as low as 10% of baseline, while seizures were evident in animals receiving 0.6 x LD(50) of sarin as early as the second day; subsequent injections led to incapacitation and death. Animals receiving 0.5 x LD(50) sarin showed obvious signs of cholinergic toxicity; overall, 2 of 13 animals receiving 0.5 x LD(50) sarin died before all 10 injections were given, and there was a significant increase in the angle of gait in the animals that lived. By the 10th day of injection, the animals receiving saline were significantly easier to remove from their cages and handle and significantly less responsive to an approaching pencil and touch on the rump in comparison with the first day of testing. In contrast, the animals receiving 0.4 x LD(50) sarin failed to show any significant reductions in their responses to an approaching pencil and a touch on the rump as compared with the first day. The 0.5 x LD(50) sarin animals also failed to show any significant changes to the approach and touch responses and did not adjust to handling or removal from the cage from the first day of injections to the last day of handling. Thus, the guinea pigs receiving the 0.4 and 0.5 x LD(50) doses of sarin failed to habituate to some aspects of neurobehavioral testing. Spectral analysis of EEG data suggested that repeated sarin exposure may disrupt normal sleeping patterns (i.e., lower frequency bandwidths). While these EEG changes returned to relative normalcy 6 days after the last injection in animals receiving 0.4 x LD(50) sarin, these changes were still observed in the animals that received 0.5 x LD(50) sarin. Ten to twelve days after the last sarin injection (in 0.4 x LD(50) group only), neurochemical data showed that striatal choline levels were reduced in comparison to the saline group. At this time, atropine sulfate (5 mg/kg, i.p.) challenge resulted in a transient elevation in striatal ACh levels in animals exposed to repeated 0.4 x LD(50) sarin as well as in control animals. No evidence of brain or heart pathology was found in any guinea pig that survived all 10 sarin injections.     

Trimethyltin disrupts acoustic startle responding in adult rats

Trimethyltin (TMT) is a limbic-system toxicant which also produces sensory dysfunction in adult animals. In the present experiment, we examined the effects of TMT on the acoustic startle response. Adult male, Long-Evans rats (N = 12/dose) received a single i.p. injection of either 0, 4.0, 5.0 or 6.0 mg/kg TMT hydroxide as the base. The number of responses, latency and peak amplitude of the startle response to a 13 kHz, 120 dB tone were measured 2 h, 2 weeks, and 4 weeks after dosing. For each test session, 10 stimuli were presented at each of three background noise levels (50, 65 and 80 dB). By 2 h after dosing, the number of responses and response amplitude were decreased following 4.0-6.0 mg/kg TMT; these treatment effects persisted through 4 weeks after dosing. Increases in latency were also seen following all dosages of TMT. These data suggest that TMT produces disruption of function within the acoustic-startle pathway.     

7种化合物细胞毒性与小鼠急性毒性的相关性研究

目的：为减少实验动物的使用,利用化学物质的体外细胞毒性数据对体内急性毒性进行预测。方法：MTT比色法检测7种新化学实体对CHL细胞的毒性作用,利用RC（Registry of Cytotox-icity）预测模型对急性毒性LD50值进行预测,并使用小鼠急性毒性上下法进行验证。结果：各化合物（1～7）细胞毒性IC50值分别为0.43、0.49、0.18、0.67、3.03、1.68、1.79mg/mL;根据RC预测模型,急性毒性LD50的预测值分别为2376.4、2478.3、1574.8、2087.6、4897.3、3331.8、3300.7mg/kg。经上下法检测,4号化合物的LD50值为1634.0mg/kg,其余6种化合物的LD50值均大于2000.0mg/kg。分别以预测值和实测值为依据对化合物毒性进行分级,二者相比,仅3号和4号化合物毒性分级略有差异,其它5种化合物的毒性分级基本一致。结论：体外细胞毒性数据可用来预测体内急性毒性,减少实验动物使用。     

Acute and repeat-dose toxicity studies of the (6-maleimidocaproyl)hydrazone derivative of doxorubicin (DOXO-EMCH), an albumin-binding prodrug of the anticancer agent doxorubicin

The (6-maleimidocaproyl)hydrazone derivative of doxorubicin (DOXO-EMCH) is an albumin-binding prodrug of doxorubicin with acid-sensitive properties that demonstrates superior antitumor efficacy in murine tumor models, and has been evaluated in a phase I study. In order to establish the toxicity profile of this prodrug, acute and repeat-dose toxicity studies were performed with DOXO-EMCH in CD1-mice, Sprague-Dawley rats and Beagle dogs. Although the objective of the acute toxicity studies was not the determination of LD50 values, the LD50 of DOXO-EMCH was >60 mg/kg doxorubicin equivalents in both male and female mice (the LD50 of doxorubicin in CD-1 mice is -12 mg/kg). In Sprague-Dawley rats, the LD50 was 23.4 and 45.9 mg/kg doxorubicin equivalents for males and females, respectively. For comparison, the LD50 of doxorubicin in Sprague-Dawley rats is -10.5 mg/kg. The major clinical sign noted following intravenous administration of DOXO-EMCH in mice and rats was a dose-dependent peripheral neuropathy which, in general, developed as a delayed toxicity 1-3 weeks after application. The observed neurotoxicity has been well documented for Sprague-Dawley rats treated with doxorubicin at a dose of 5 and 10 mg/kg. In Beagle dogs, LD10 was not reached for DOXO-EMCH at 4.5 mg/kg doxorubicin equivalents. A four-cycle intravenous study with DOXO-EMCH at dose levels of 4 x 2.5, 5.0 or 7.5 mg/kg doxorubicin equivalents in rats revealed approximately three-fold less side effects on the hemolymphoreticular system when compared to 4 x 2.5 mg/kg doxorubicin dose, whereas effects on the testes/oligospermia seem to be comparable between both drugs at equitoxic dose. A No Observable Adverse Effect Level (NOAEL) for DOXO-EMCH of 4 x 2.5 mg/kg doxorubicin equivalents was established in this study. This dose is equivalent to the maximum tolerated dose (MTD) of doxorubicin in rats. In a two-cycle study over a period of 6 weeks in Beagle dogs (intravenous administration of DOXO-EMCH at dose levels of 1.5, 3.0 or 4.5 mg/kg doxorubicin equivalents), dose-related systemic histamine-like reactions within the first 3 hours after injection were noted in all treated groups. Only transient and temporary effects on hematology, urinary function, as well as on histopathology in mid- and/or high-dose animals, were observed. The low dose of 2 x 1.5 mg/kg was considered to be the NOAEL in this study, which is equivalent to twice the MTD o f doxorubicin i nBeagle dogs. In summary, the toxicity studies with DOXO-EMCH in mice, rats or dogs have not identified any other special toxicity when compared to the toxicity data for doxorubicin. Preclinical tolerance of DOXO-EMCH was higher in mice, rats and dogs compared to doxorubicin. A dose of 20 mg/m2 doxorubicin equivalents was recommended as the starting dose for a phase I study with DOXO-EMCH.     

氢溴酸樟柳碱注射液大鼠单次和重复给药毒性试验研究

目的 通过SD大鼠的单次和重复静脉给药毒性试验,评价氢溴酸樟柳碱注射液的安全性。方法 单次给药毒性试验采用最大耐受量法,观察大鼠的死亡情况和毒性反应。重复给药毒性试验：将大鼠随机分为溶媒对照组和氢溴酸樟柳碱10、50、200 mg/kg剂量组,每组30只,尾iv给药,连续13周,停药恢复4周。进行各项毒理学指标检测。结果 急性毒性试验：氢溴酸樟柳碱注射液在364.5~504.5 mg/kg对大鼠产生明显毒性,症状有给药时尖叫、俯卧、后肢无力、颤抖、抽搐、惊厥、瞳孔散大、尾部发绀等,甚至造成个别动物死亡。重复给药毒性试验：50、200 mg/kg剂量组出现体质量增长减缓,摄食下降,给药后尖叫,鼻端、眼周异常分泌物增多,皮肤脱毛、结痂,耳廓溃疡、缺损,瞳孔散大,尾部发绀,血红蛋白（HGB）、红细胞压积（HCT）、Cl-浓度升高等症状,200 mg/kg剂量组还出现给药后肌张力减退、颤抖、抽搐、呼吸困难、皮下炎性包块等表现。溶媒对照组和200 mg/kg剂量组动物注射部位均出现静脉炎及静脉周围炎,严重程度无差异,停药4周后病变减轻。结论 氢溴酸樟柳碱注射液SD大鼠静脉单次给药的最大耐受量（MTD）为428.8 mg/kg,约相当于临床剂量的2 573倍;重复给药毒性试验未见明显毒性反应剂量（NOAEL）为10 mg/kg,约相当于临床剂量的60倍。     

The curative power of 4-(2:6-diaminopyrimidin-4-ylamino)phenylarsine oxide (compound 12,065) in infections of trypanosoma rhodesiense in laboratory animals

The toxicity to laboratory animals of 4-(2:6-diaminopyrimidin-4-ylamino)phenylarsine oxide (compound 12,065), and its ability to cure laboratory infections of Trypanosoma rhodesiense were investigated. The intramuscular LD50 to mice was 22 mg./kg.; rats were more susceptible. Monkeys tolerated two daily doses of 6 mg./kg., but not two daily doses of 10 mg./kg. The intramuscular CD50 to mice was about 6 mg./kg. with two strains of T. rhodesiense recently isolated from human patients, and 2 mg./kg. with a strain of T. rhodesiense which had been maintained by cyclical transmission through tsetse flies in the laboratory for about 17 months. These results are compared with those reported by Ainley and Davey (1958) for a strain of T. rhodesiense which had been maintained in the laboratory by cyclical transmission for about 12 years and then by syringe transmission for about 10 years. The syringe-transmitted strain was at least 20 times more susceptible to the drug than the recently isolated strains. The potencies of compound 12,065 and melarsen oxide/BAL in curing T. rhodesiense infections in mice were compared: the CD50 for compound 12,065 was 6.5 mg./kg. and for melarsen oxide/BAL was 3.7 mg./kg. The ratios LD50/CD50 for the drugs were about 4 and 6 respectively.     

Lithium-methomyl induced seizures in rats: a new model of status epilepticus?

Behavioral, electroencephalographic (EEG) and neuropathological effects of methomyl, a carbamate insecticide reversibly inhibiting acetylcholinesterase activity, were studied in naive or lithium chloride (24 h, 3 mEq/kg, s.c.) pretreated male Wistar rats. In naive animals, methomyl with equal potency produced motor limbic seizures and fatal status epilepticus. Thus, the CD50 values (50% convulsant dose) for these seizure endpoints were almost equal to the LD50 (50% lethal dose) of methomyl (13 mg/kg). Lithium pretreated rats were much more susceptible to convulsant, but not lethal effect of methomyl. CD50 values of methomyl for motor limbic seizures and status epilepticus were reduced by lithium pretreatment to 3.7 mg/kg (a 3.5-fold decrease) and 5.2 mg/kg (a 2.5-fold decrease), respectively. In contrast, lithium pretreatment resulted in only 1.3-fold decrease of LD50 value of methomyl (9.9 mg/kg). Moreover, lithium-methomyl treated animals developed a long-lasting status epilepticus, which was not associated with imminent lethality observed in methomyl-only treated rats. Scopolamine (10 mg/kg) or diazepam (10 mg/kg) protected all lithium-methomyl treated rats from convulsions and lethality. Cortical and hippocampal EEG recordings revealed typical epileptic discharges that were consistent with behavioral seizures observed in lithium-methomyl treated rats. In addition, convulsions induced by lithium-methomyl treatment were associated with widespread neurodegeneration of limbic structures. Our observations indicate that lithium pretreatment results in separation between convulsant and lethal effects of methomyl in rats. As such, seizures induced by lithium-methomyl administration may be an alternative to lithium-pilocarpine model of status epilepticus, which is associated with high lethality.     

The effects of acrylamide given acutely or in repeated doses on fore- and hindlimb function of rats.

Male, albino rats of the Fischer strain were given 50 to 250 mg/kg acrylamide orally. The LD50 (and 95% confidence intervals) was estimated to be 251 mg/kg (203–300) at 24 hr postdosing and 175 mg/kg (159–191) at 168 hr postdosing. Rats given 50, 100, and 200 mg/kg acrylamide orally were tested for muscular dysfunction at 12 and 168 hr post-dosing. At 12 hr after dosing, acrylamide produced marked deficits in hindlimb motor functioning, as measured by the hindlimb extensor test and performance on the inclined screen. Recovery of hindlimb function was complete at 168 hr after dosing. Forelimb grip strength was not affected at either test period. In a 4-week repeated dosing experiment, rats given 10 or 20 mg/kg/day, 5 days per week, showed hindlimb dysfunction at a cumulative dose of 50 to 100 mg/kg while rats receiving up to 400 mg/kg over a period of 4 weeks showed no signs of diminished forelimb grip strength. Recovery of hindlimb motor function was evident, but not complete, 2 weeks after cessation of dosing. The tests of motor function used in this study were sensitive to and capable of detecting specific motor deficits in rats treated with relatively low doses of acrylamide. The rapidity and ease with which the tests can be used in experiments involving repeated measures suggest their use in assessing other chemicals for potential neurotoxicity.     

An overview of in vivo toxicological profile of thymoquinone

Abstract

Thymoquinone (TQ) is a naturally occurring quinone derivative and its metabolism may produce reactive oxygen species which in turn may lead to various adverse effects. Here, we discuss in vivo data concerning toxicological effects of TQ. Previous studies showed LD50 values of 250–794?mg/kg in rats and 300–2400?mg/kg in mice for oral TQ but 57?mg/kg in rats and 90.3–104?mg/kg in mice for intraperitoneal TQ. In subacute toxicity evaluations, NOAEL was about 10?mg/kg. Though TQ has been found as an almost safe chemical, detailed studies are required before introducing TQ as a therapeutic agent for human use.     

Toxicological study of pyridoxal isonicotinoyl hydrazone: acute and subchronic toxicity.

Pyridoxal isonicotinoyl hydrazone (PIH) is a highly effective iron chelator. Acute toxicity testing was performed in mice and rats of both sexes, with 10 mice or rats/sex/group. The LD50 values of PIH in both species were 5 and 1 g/kg given orally and intraperitoneally, respectively. Microscopic examination of tissues from the highest oral dose (6 g/kg) animals that survived 7 days revealed fatty degeneration in the liver. Subchronic toxicity was tested in rats of both sexes, with 8 males and 8 females/group. PIH doses of 100, 400 and 800 mg/kg were given orally for 90 consecutive days. Water was given to the control group. Hematocrit and blood chemistries were analysed at weeks 3, 6, 10 and 13. There were no changes in hematocrit and BUN. PIH at doses of 800 mg/kg caused a significant increase in serum alkaline phosphatase and transaminase levels at week 13. Microscopic examination showed hepatic degeneration in a dose-related fashion. Vascular congestion of the kidney and spleen was also found. No histopathological changes were detected in sections from the stomach and intestine.     

Antiviral effect of 1-morpholinomethyl-tetrahydro-2(1H)-pyrimidinone (DD-13) in experimental alphaviral infections in white mice

1-Morpholinomethyl-tetrahydro-2(1H)-pyrimidinone (DD-13), a selective inhibitor of the alphaviral reproduction in vitro, manifests a pronounced antiviral activity in experimental infections with Semliki forest virus (SFV) and Sindbis virus in white mice (intraperitoneally inoculated with 10-10 000 LD50). Introduced subcutaneously in mice infected with SFV the compound was effective within the dose range of 4.7-300 mg/kg. The effective dose (ED)50 value of DD-13 is about 18.7 mg/kg and the maximum effect is reached with a 150-300 mg/kg dose. The protection index reached 80% and the mean survival time from approximately 7 days in the placebo group was lengthened to 26 days. This high antiviral effect is distinguished by its high selectivity, the selectivity ratio (LD50/ED50) being 385 (LD50 = 7200 mg/kg) and is manifested in infections with massive viral inocula (100-1000 LD50). The effective treatment schedule was determined: two divided daily doses of 37.5-150 mg/kg, beginning on the 3rd day after infection to the 8th day. After intravenous administration of DD-13 in mice infected with SFV a high protective effect was also observed, which was equal to that of the subcutaneous application, but with doses several times lower: in the 3-40 mg/kg. ED50 is about 3.5 mg/kg and the optimal effective dose is 10-20 mg/kg, i.e. 1/12-1/6 of LD50 (116 mg/kg). The selectivity ratio is about 33. The most effective treatment course is accomplished by a 10-20 mg/kg daily dose (in two applications) starting on the 2nd day after the virus inoculation up to the 8th day.(ABSTRACT TRUNCATED AT 250 WORDS)