[Twenty-eight day repeated dose toxicity test of dicyclopentadiene in F344 rat]

A twenty-eight day repeated dose toxicity test of dicyclopentadiene (DCPD) was carried out in male and female F344 rats at the dose levels of 200, 40, 8 or 0 mg/kg/day. Thirty six animals of both sexes were divided into 6 groups of equal number. All groups were treated i.g. administration for 28 days daily, and two groups of them, at the dose levels of 200 and 0 mg/kg, were used for investigation of recovery. Inhibition of body weight gain was observed in the 200 mg/kg groups in both sexes and the 40 mg/kg group in male, but in female this inhibition was recovered at day 17 of the treatment. Increases in liver and adrenal gland weights, and decrease in thymus weight were noted in the 200 mg/kg groups in both sexes, and increase in kidney weight was also observed in the 200 and 40 mg/kg groups in male. On histopathological examination, hypertrophy of the adrenal cortex, and foamy cytoplasm in hepatocytes were observed in the 200 mg/kg groups of both sexes. Repair of histopathological lesions occurred within 14 days resting period. Based on these findings, it was concluded that the No Observed Effect Level of DCPD would be 8 mg/kg/day.

Synthesis and CNS activity of some new substituted indeno [1,2-c] pyrazoles

Some new 1-(6'-substituted-4'-methylquinol-2'-yl)-3-methyl-indeno[1,2- c]pyrazoles (Va-d) have been synthesized by the condensation of 2-acetylindane-1,3-dione (I) with 2-hydrazino-4-methyl-6-substituted quinolines (IIa-d), followed by cyclodehydration with polyphosphoric acid and Wolff-Kishner reduction. Compounds (IVa-d) showed noticeable CNS activity.

Central effects of the neurotropic mycotoxin fumitremorgin A in the rabbit (I). Effects on the spinal cord

Effects of a potent neurotropic mycotoxin, fumitremorgin A (FTA), on the spinal cord were studied, using rabbits lightly anesthetized with urethane and chloralose. Spontaneous discharges of L7 spinal ventral roots and common peroneal nerves were increased after intravenous injection of 100-200 micrograms/kg of FTA. Their abnormal discharge pattern represented the convulsive effect of FTA. Spinal monosynaptic reflexes became irregular in amplitude, with a slight predominance of smaller reflexes. Polysynaptic reflexes were inhibited in many cases. These FTA-induced changes in ventral root discharges and spinal reflexes were abolished by spinal transection at a segment of the upper level. These results suggest that FTA may have no direct facilitatory action on spinal motoneurons and that its remarkable motor effect has its origin in the supraspinal central nervous system.

New congeners of antihypertensive and antithrombotic 7-amino or 7-acetyl-aminosubstituted-4,4a-dihydro-5H-indeno (1,2-c)pyridazin-3-ones

New congeners of the antihypertensive and antithrombotic 7-amino-(I b) and 7-acetylamino-4,4a-dihydro-5H-indeno(1,2-c)pyridazin-3-one (I c) have been synthesized and evaluated pharmacologically. Compounds (I k) (R = 7-NHCH3), (I l) (R = 7-N(CH3)COCH3) and (I m) (R = 7-N(CH3)COC2H5) exhibited an antihypertensive effect similar to that of (I b) and (I c), though short lasting. The antithrombotic activity of six compounds was found comparable to or higher than that of acetylsalicilic acid. In particular, (I l) and (I m) fully protected mice against thrombosis, as did the reference compound (I c).

Structure-toxicity relationships of the tetramethylated tetralin and indane analogs of retinoic acid

The teratogenicity of retinoids containing either tetramethylated tetralin (Ro 13-6307 or Ro 13-2389) or tetramethylated indane (Ro 13-4306) ring system substitutions was compared to the teratogenic potency of all-trans-retinoic acid. Single oral doses, administered to Syrian Golden hamsters at 10:00 A.M. on day 8 of gestation, induced a syndrome of malformations identical to that induced by treatment with all-trans-retinoic acid. These retinoids failed to induce signs of maternal hypervitaminosis A at doses associated with a significant teratogenic response. The tetramethylated tetralin retinoids and indane retinoid were 18 and 2.4 times as embryotoxic on a molar basis, respectively, as all-trans-retinoic acid. Introduction of a supplementary ring in the side-chain restricted polyene chain flexibility and maintained the hydrophobic plane of the chain. The present results are consistent with previous studies showing that the presence of or biotransformation to a free acid congener was necessary for retinoid teratogenic activity in hamsters and that increasing conformational restriction of acidic retinoids increased teratogenic potency.

Ototoxicity of indacrinone is stereospecific

Indacrinone (MK-196) is a loop diuretic which consists of a racemic mixture. The purpose of this study was to evaluate the individual enantiomers in the chinchilla model to determine whether these compounds affect auditory function and whether a difference in ototoxic potency exists. Very little change of endocochlear potential (EP) or compound action potential (CAP) was noted in animals receiving the (+)-enantiomer. On the other hand, chinchillas injected with the (-)-enantiomer were found to have a dose related reduction in both CAP and EP. These findings suggest the possibility that the diuretic receptor in the kidney and the receptor mediating ototoxicity in the cochlea, may have similar steric requirements for interacting with loop diuretics.

The effects of sulindac and its metabolites on acute stress-induced gastric ulcers in rats

Rats were given a single intragastric administration of the prodrug sulindac (4.0 mg/kg) or its sulfide (1.0, 2.0, 4.0, or 8.0 mg/kg) or sulfone (1.0, 2.0, 4.0, or 8.0 mg/kg) metabolites and were then subjected to acute stress in the form of immobilization for 3 hr in a cold environment. Control rats received an equal volume of propylene glycol vehicle or nothing po. Other rats received 200 mg/kg acetylsalicylic acid (ASA) with or without stress, to compare the gastrointestinal effects of sulindac metabolites with those of a known non-steroidal anti-inflammatory agent. The sulfide metabolite exacerbated stress-induced gastric glandular ulcer incidence and severity in a dose-related manner relative to all groups except the ASA-stress group, which exhibited the greatest amount of gastric damage. The sulfone metabolite did not potentiate ulcer incidence or severity beyond control (stress only) levels at lower doses. However, at 4.0 and 8.0 mg/kg, the observed ulceration was greater than that seen in stressed but otherwise untreated animals. Sulindac, vehicle, and otherwise untreated rats exhibited a similar degree of stress-induced gastric damage. It appears that the prodrug does not significantly enhance stress-related gut disease, but that the active sulfide metabolite does. Although the clinical literature suggests that the sulfone metabolite is inactive, the present results suggest otherwise. While this metabolite did not, by itself, induce gastric damage at higher doses, sulfone did exacerbate stress ulcer formation. This is the only report of which we are aware, indicating a possible toxic effect of the sulfone metabolite.

Analgesic and anti-inflammatory activity of 10-amino-11H-indeno [1,2-b] quinolin-11-one derivatives

Ten novel derivatives of 11H-indeno [1,2-b] quinolin-11-one (1-10) were synthesized and pharmacologically screened. All compounds showed analgesic activity. Anti-inflammatory activity was found only for alkylamine derivatives 1-6. The most active 10-ethylamine derivative 2 showed also ulcerogenic properties. The LD50/UD50 and UD50/ED50 values for compound 2 were less satisfactory than those for ibuprofen.

Evaluation of the antiabortifacient and embryotoxic effects of methylenedioxyindene and methylenedioxyindan calcium antagonists

Calcium channel blockers have been advocated as potential therapeutic agents in the management of premature labor. In the present study, the class of intracellular calcium antagonistic methylenedioxyindenes (MDIs) was investigated for potential antiabortifacient activity in mice. Pretreatment of pregnant mice from day 15 of gestation with the MDIs did not afford protection against the abortifacient effect of prostaglandin F2alpha administered from day 17 of gestation. The MDIs demonstrated embryotoxic and fetotoxic activity as shown by a significant increase in the incidence of resorptions and stillbirths. Similar embryotoxicity was previously reported for the calcium channel blockers. It appears doubtful that any of the calcium antagonists so far examined will be clinically useful in the management of premature labor.

Histologic and cytogenetic effects of redentin on the spermiogenesis and bone marrow cells of the mouse, an in vivo experiment

The chromosomes in bone marrow cells and spermatocytes of Redentin (1 X 20 mg/kg, po)-treated CFLP strain male mice were examined. Spermiogenesis was checked histologically. On the basis of the results, it can be stated that Redentin, at this experimental dosage, did not induce chromosome aberrations nor did it damage spermiogenesis.

Sulindac hepatotoxicity: a case report and review

A 44 year old female, previously on propranolol, phenytoin and phenobarbital, developed hepatotoxicity while on sulindac and acetaminophen containing analgesic. A limited review of hepatotoxicity and drug interactions of sulindac is presented. The possible mechanism of hepatotoxicity and its treatment is suggested.

Comparison of anticonvulsive properties of eboracin and phenytoin in mice

The in vivo effects of phenytoin (diphenylhydantoin, Dilantin) and the experimental anticonvulsant, eboracin, a substituted indenopyrrole, were compared in mice. Pretreatment with varying dosages of either agent followed by challenge with the chemoconvulsant pentylenetetrazol (Metrazol) indicated that eboracin provided slightly less protection against seizures than phenytoin and was much less toxic. Intermediate doses of either agent led to a form of clonic status epilepticus which persisted for an average of 18 min in phenytoin-treated and 58 min in eboracin-treated mice. Pretreatment with higher or lower doses did not lead to these manifestations. Animals in which this syndrome had been induced should be of value in studies of the chemistry and physiology of the clonic state.

Abnormal behavioral effects elicited by a neurotropic mycotoxin, fumitremorgin A in mice

Fumitremorgin A (FTA), a neurotropic mycotoxin induced dose-dependent abnormal behaviors, including tremor, clonic convulsion, kangaroo posture and tonic extensor convulsion in the mouse. FTA-induced tonic extensor convulsion was markedly suppressed by anticonvulsant, e.g. phenobarbital, phenytoin. Phenobarbital, trimethadione, valproic acid and mephenesin decreased the occurrence of abnormal behaviors induced by FTA. Although pentylenetetrazol-induced tonic extensor convulsion was not affected by antipsychotic drugs (dopaminergic drugs) except chlorpromazine, FTA-induced abnormal behaviors were inhibited by antipsychotic drugs, e.g. chlorpromazine, haloperidol. Chlordiazepoxide, diazepam and muscimol inhibited FTA-induced abnormal behaviors. These findings suggest that both dopaminergic and gamma-aminobutyric acid (GABA)-ergic systems are involved in FTA-induced abnormal behaviors. FTA-induced abnormal behaviors may be useful as a common experimental model for the primary evaluation of anticonvulsants, antipsychotic drugs and anxiolytic drugs.

Biochemical investigation on the abnormal behaviors induced by fumitremorgin A, a tremorgenic mycotoxin to mice

The relationships between behavioral responses and levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in brain of mice were investigated after intravenous injection of fumitremorgin A (FTA). The latent periods to the onset of tremor, clonic convulsion, tonic convulsion and death induced by FTA are observed in a dose-dependent fashion. However, the dose-dependency is not observed between levels of 5-HT and 5-HIAA and activities of 5-HT metabolizing enzymes in brain of FTA-treated mice. Insignificant participation of serotonergic mechanism in modulation of those behavioral states elicited by FTA is conclusively suggested.

Evaluation of the embryotoxicity of JP-10 in the rat

The effect of JP-10, the major component of cruise missile fuel, on the development of embryonic rats was evaluated. Pregnant females were exposed via inhalation to 600 ppm or orally dosed with 250, 500 or 1000 mg JP-10/kg on gestation days 6-15. In a separate experiment both fetal and maternal blood levels of JP-10 were monitored during an inhalation exposure. Moderate signs of toxicity including tremors and convulsions were observed in the pregnant females receiving the higher doses. JP-10 was not selectively embryotoxic in the rat when administered by gavage or inhalation. Blood levels of JP-10 in the fetuses were about one half the maternal blood levels at steady state.

[Manifestations of the neurotoxicity of the organochlorine pesticide dilor during the postnatal period in the rat]

When pregnant rats are administered chlororganic pesticide dilor, certain ultrastructural changes are observed in neurocytes and in myelin fibers, in the spinal cord, that demonstrates some disorders in cellular and tissue metabolism. In the newborn spinal cords a retarded differentiation is observed against the background of an intense cellular metabolism. By means of the electron paramagnetic resonance technique, an increasing concentration of free radicals in the brains and spinal cords of the pregnant animals and in their one-month-old offsprings is demonstrated. The investigation on fatty acid composition of lipids in pregnant test animals demonstrates a decrease in cholysterine, steroids and some fatty acids in myelin fractions and in synaptosomic membranes.

Effect of 2 anti-arrhythmic drugs aprindine and moxaprindine on the replication capacity of murine and human haemopoietic cells

Aprindine, a potent anti-arrhythmic agent, occasionally seems responsible for agranulocytosis. In order to study its potential haematological toxicity, 3 different in vitro tests were used: (a) the capacity of human and mice bone marrow to incorporate tritiated thymidine (3HTdR), (b) the capacity of stimulated human blood lymphocytes to incorporate 3HTdR and (c) the capacity of human granulocyte-macrophage stem cells to form colonies in agar. For all these tests aprindine was found to be toxic at concentrations close to the clinical therapeutic serum concentration. Moxaprindine, chemically very close to aprindine exhibits also an anti-arrhythmic activity. It was examined in the same tests in parallel with the study af aprindine. Moxaprindine also exhibited haematological toxicity in the tests but at a significantly higher concentration, approximately twice that of aprindine. Assuming that these in vitro tests are relevant to the in vivo haematological toxicity, moxaprindine could be considered a clinically safer anti-arrhythmic agent than aprindine.

Toxicologic evaluation of diisopropyl methylphosphonate and dicyclopentadiene in cattle

Diisopropyl methylphosphonate (DIMP), and dicyclopentadiene [3a,4,7,7a-tetrahydro-4,7-methyanoindene] (DCPD), were found as contaminants of groundwater in Colorado. Since there was a potential for cattle to be exposed to these chemicals by drinking well water, a study of their effects was initiated. Eight-to-ten week old calves were given a single dose of either DIMP at 62.5, 125, 250, 500 and 1000 mg/kg of body weight (b.w.) or DCPD at 250, 500, 1000 or 2000 mg/kg of b.w. The calves given DIMP developed tympanitis and ataxia, followed by depression, prostration, and death within two hr after dosing. A slight but significant increase in activated partial thromboplastin time was the only change observed in any of the clinical pathologic parameters. The only gross pathologic changes were acute gastroenteritis with hemorrhages in calves given 1000 mg/kg of b.w. Mild signs of intoxication, ataxia and excess salivation, were observed in calves given 250 mg of DCPD/kg of b.w. At higher doses, these signs were intensified; in addition, calves fell and, while prostrate, exhibited running movements and tonic, clonic spasms. The severity of the signs observed increased as the dose of DCPD increased. All calves given 2000 mg/kg of b.w. and one calf given 1000 mg/kg of b.w. died before seven days after dosing. The only clinical pathologic changes found were increased serum levels of creating phosphokinase, glutamic-oxalacetic transaminase, and glutamic pyruvic transaminase. The only consistent gross pathologic change was congestion in a variety of tissues in calves given 2000 mg/kg of b.w. A variety of histologic changes were observed in tissues from calves treated with both chemicals. However, these changes were not consistent for any one dose level and were not dose dependent. DIMP was slightly toxic for calves, since no signs of intoxication were observed at doses less than 1000 mg/kg of b.w. DCPD exerted detrimental effects on calves at 250 mg/kg of b.w. and was classified as moderately toxic.

Drug-induced histological changes in rat seminiferous tubular epithelium

It is proposed to divide antispermatogenic compounds into four main groups on the basis of the morphological changes which they cause: a) Radiomimetic substances (e.g., Busulfan). These have a direct effect on spermatogonia and hence also on later sperm development. b) Substances inhibiting the meiotic and postmeiotic phases of spermatogenesis. These cause the seminal epithelium to disappear rapidly except for spermatogonia and Sertoli cells, which apparently remain intact (e.g., 20-438, an indenopyridine derivative). c) Substances acting hormonally (via pituitary). These severely damage Leydig cells, and there is a particularly pronounced degeneration of later stage spermatids. Sertoli cells are also affected. The tunica propria becomes thicker. The weights of the accessory sex glands decrease, and the pituitary weight increases. The peritubular tissue in the epididymis becomes thicker (e.g., 17 beta-estradiol). d) Vasoactive substances (e.g., cadmium chloride). These cause spot-like necrosis. Whole tubuli are destroyed (similar to infarction) whereas others can remain intact. Leydig cells also degenerate, and there is fibroblastic proliferation in the interstitium. The peritubular tissue in the epididymis becomes thicker and the secretion of clear cells is affected. Accessory glands lose weight.