Induction of ethylenediamine hypersensitivity in the guinea pig and the development of ELISA and lymphocyte blastogenesis techniques for its characterization

Ethylenediamine (EDA) is reported to be a poorly characterized iatrogenic and occupational contact sensitizer. To better characterize EDA hypersensitivity, a guinea pig model was employed in which the animals were exposed epicutaneously to simulate conditions of human exposure, and selected immune parameters were measured. Induction of hypersensitivity was by the Buehler occluded patch method (6 hr application/day, once a week for 3 consecutive weeks) to 10, 20, 30, or 40% EDA, using either an ethanol or acetone/corn oil vehicle. Fourteen days after the last induction, guinea pigs were challenged by patch application of 2% EDA (nonirritating). The incidence of responders for erythema in the 10% EDA (ethanol) treatment group was 83 and 50% at 24 and 48 hr, respectively. In the 10% EDA (acetone/corn oil) group the corresponding values were 50 and 17%. For 20, 30, and 40% EDA, in either vehicle, the incidence of erythema was 83 to 100%. Severity grades (scale = 0-3) for cutaneous reactions to increasing concentrations of EDA in ethanol ranged from 0.8 to 2.5; those for EDA in acetone/corn oil ranged from 0.6 to 2.8. Using an enzyme-linked immunosorbent assay developed to detect the predominant serum antibodies to EDA, it was shown that guinea pigs treated by patch application did not produce the main allergic antibody IgG specific for EDA. However, intradermal administration of an EDA-guinea pig serum albumin conjugate (EDA-GSA) to guinea pigs presensitized by patch application resulted in antibody production by 39 and 86% of the animals, at the initial and second dosing, respectively. An in vitro blastogenesis assay, using peripheral blood lymphocytes from EDA-sensitized guinea pigs, was developed to identify specific chemical allergens implicated in vivo sensitization. Maximum tritiated thymidine ([3H]TdR) incorporation by lymphocytes stimulated in vitro with EDA-GSA was observed on Day 7. Optimal antigen concentration for maximum lymphocyte proliferation ranged from 5 to 50 micrograms/ml, the major variation being attributable to interanimal differences. These results indicate that epicutaneous application of EDA in the guinea pig induces a Type IV delayed hypersensitivity; immunological memory to the hapten is maintained in cultured lymphocytes, suggesting the potential usefulness of the lymphocyte transformation test for in vitro diagnosis of chemically induced hypersensitivity in humans.

Action of some amides of substituted ethylenediamines on central nervous system

Five of the substituted ethylenediamine amides (LMG I to V) were tested for various CNS attributes and for acute toxicity (24 hr mortality). All compounds were potent analgesics in various animal tests, LMG V being most potent. All reduced spontaneous activity of mice and potentiated ether anaesthesia. However, CAR was not altered and anti-MES were not pronounced in rats. Compounds appear to have a wide safety margin considering ED50 and LD50 in mice.

Overcoming drug resistance in cancer cells with synthetic isoprenoids

A cultured subline (P388/ADM) of mouse P388 leukemia resistant to doxorubicin, vinblastine, vincristine, dactinomycin, and daunorubicin became sensitive again when treated with noncytotoxic doses of either of two synthetic isoprenoids: N-solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine (SDB-ethylenediamine) and N-(p-methylbenzyl)decaprenylamine X HCI (PMB-decaprenylamine). The isoprenoids also reversed resistance to doxorubicin and vincristine in a cultured vincristine-resistant P388 leukemia subline (P388/VCR). Median lethal doses (LD50) for PMB-decaprenylamine and SDB-ethylenediamine administered ip were 123 and 350 mg/kg against mice, whereas the LD50 for verapamil, another modifier of cellular drug resistance, was about 7.6 mg/kg. In vivo experiments with P388/VCR-bearing mice showed that both SDB-ethylenediamine and verapamil overcame vincristine resistance, but PMB-decaprenylamine showed only slight activity. SDB-ethylenediamine was especially effective, overcoming the vincristine resistance at 1 mg drug/kg. Since the structure of SDB-ethylenediamine resembles that of verapamil, a calcium-blocking agent that overcomes drug resistance, it was checked for calcium-blocking activity. However, calcium channel-blocking activity was not observed with 20 micrograms isoprenoid/ml, whereas calcium channel activity was completely blocked by 1 microgram verapamil/ml.

Preliminary toxicity findings in dogs and rodents given the iron chelator ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) (EDHPA)

Because of a projected pilot study with EDHPA in Cooley's anemia patients, animal studies with emphasis on reversibility of potential toxic signs were performed. Young dogs were treated iv with 6-18 mg/kg or orally with 30-240 mg/kg for 14 days followed by a 16-day recovery period. Drug-induced emesis, elevated BUN changes in kidney, spleen, and thymus weights diminished during recovery. One deceased dog exhibited nephrotoxicity consisting of tubular necrosis and deposition of the iron-EDHPA complex. The latter was observed in the excreta of survivors but kidney damage was not evident. Atrophy of the spleen and thymus in the deceased dog was consistent with less intense organ weight changes in recovered survivors. In the absence of morphologic changes after recovery, the precise effect on the immune system is unknown. The iv LD50 was 53 mg/kg for rats and mice. No rodent deaths occurred at an oral dose of 6000 mg/kg. An elevated BUN and changes in kidney, spleen, and thymus weights were confirmed in rodents given iv doses of 5-20 mg/kg or oral doses of 150-600 mg/kg for 5 days. It is cautioned that during the use of EDHPA derivatives that the functions of the renal and immune systems be monitored.

Antimalarial activities and subacute toxicity of RC-12, a 4-amino-substituted pyrocatechol

RC-12 [1,2-dimethoxy-4-(bis-diethylaminoethyl)-amino-5-bromobenzene] was evaluated for prophylactic, radical curative, and suppressive activities against infections with Plasmodium cynomolgi and subacute toxicity in rhesus monkeys. Applied as a prophylactic agent, RC-12, administered in doses of 6.25 to 25.0 mg/kg daily throughout the incubation period, provided near-complete to complete protection against 10(5) to 10(6) times the minimum infective dose of sporozoites. Applied as a suppressive agent, daily doses of 100.0 mg of RC-12 per kg did not eradicate blood schizonts regularly; hence, the need for concomitant administration of a blood schizonticide, such as chloroquine, in assessments of radical curative activity. In such appraisals, daily doses of 6.25 to 25.0 mg of RC-12 per kg for 14 days, in combination with 2.5 mg of chloroquine per kg daily for 7 days, effected cure of 69 and 93% of established infections, respectively. The curative activity of RC-12 was related to the total dose and could be achieved with a regimen as brief as 4 days. With respect to outward expressions of toxicity, daily doses of 50.0 mg/kg or lower for 15 to 225 days evoked no reactions. Doses of 100.0 or 200.0 mg/kg, scheduled for 15 days, evoked convulsions and depression and were, respectively, lethal to 4 of 17 and 7 of 7 recipients. Doses of 25.0 mg/kg or lower evoked no discrete reactions. Doses of 50.0 mg/kg and higher evoked hepatomegaly, vacuolation of hepatocytes, and elevations of glutamic oxalacetic and glutamic pyruvic transferase activities in serum, reactions related in intensity to dose but not duration of dosage.

Dermal oncogenicity studies on ethylenediamine in male C3H mice

The dermal oncogenic potential of ethylenediamine (EDA) was assessed by applying 25 microliter of a 1% solution in deionized water to the skin of 50 male C3H/HeJ mice. This was the highest concentration not producing irritation or weight changes in a preliminary 2-week study. Two EDA samples (Nos. 1 and 2) from different production sources were tested. Applications were made thrice weekly until the death of the animals. A negative control group received deionized water only. This group and the EDA-treated groups were individually housed. A fourth group of 40 mice, housed 5 per cage, received 0.1% 3-methylcholanthrene (MC) in acetone as a positive control substance. A fifth group of 40 mice, housed 5 per cage, also received deionized water to determine the effect of group housing on survival. No skin tumors were observed in the EDA-treated groups. In the positive control group, however, 39 animals (98%) had skin tumors including 37 (92%) with confirmed squamous cell carcinomas. Eleven mice (22%) which received EDA No. 1 had dermal fibrosis indicative of probable skin irritation in this group; there was no such lesion in the controls. The mean survival times were 639, 626, and 598 days for the EDA No. 1, water control, and EDA No. 2 groups, respectively. The survival time of the EDA No. 2 group was significantly reduced compared to the individually housed water controls by one of two statistical tests. Irrespective of this difference, the study is considered to be a valid assessment of the oncogenic potential of EDA No. 2 because the magnitude of the difference in mean survival time was small.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-generation reproduction study of ethylenediamine in Fischer 344 rats

Ethylenediamine dihydrochloride (EDA X 2 HCl) was incorporated in the diet of Fischer 344 rats at dosage goals of 0.50, 0.15, 0.05, or 0 g/kg/day in a two-generation reproduction study. The parent generation (F0) and the F1 generation were each bred once. Parameters examined included indices of fertility, gestation of dams, gestation survival, 0- to 4-, 4- to 14- and 4- to 21-day survival of pups, number of pups born alive, and number of pups weaned per litter. Furthermore, observations were made on mortality, diet consumption, and body weight of the adult rats in F0 and F1 generation. Randomly selected F1 weanlings and adults and F2 weanlings were sacrificed and organ weights were obtained; in addition, gross and histologic examinations were conducted on these rats. No reproductive toxicity was observed in this study. Some effects were observed in both sexes for the F0 and F1 parent rats. These effects were mainly associated with the high dosage level and included reduction of body weight gain and changes in liver (decrease) and kidney (increase) weights in the adult rats. The only microscopic lesion observed was hepatocellular pleomorphism in the high level F1 adult males and females; a greater prevalence and severity of this lesion was seen in the female rats.

Molecular localization of copper and zinc in rat fetal liver in dietary and drug-induced copper deficiency

The teratogenicity of copper deficiency is well known, but underlying mechanisms have not been delineated. One method of studying the biochemical lesions of copper deficiency is the use of chelating drugs with different chemical characteristics. The teratogenicity of a copper deficient diet and of diets containing either D-penicillamine or triethylenetetramine is quite different, although all three diets result in decreased fetal liver copper levels. Feeding D-penicillamine can result in decreased fetal liver zinc, while feeding triethylenetetramine can result in increased fetal liver zinc. The effect of these three diets on fetal liver copper and zinc molecular localization was determined. Gel filtration showed that fetal liver copper and zinc in controls was localized in 3 fractions with MWs of greater than 50,000 (H), 30,000 (I) and 8-10,000 (L). Independent of dietary treatment, as liver copper diminished, copper was missing first from the L peak, then the I peak and with severe deficiency, from the H peak. Drug induced increases and decreases in fetal liver zinc were reflected in the L peak. These data suggest that the absolute levels of copper in the liver of the term fetus determines the distribution of the element among its binding ligands.

Assessment of genotoxic potential of ethylenediamine: in vitro and in vivo studies

Ethylenediamine (EDA) was evaluated for potential genotoxic activity using a battery in vitro and in vivo mammalian tests. The tests employed were the Chinese hamster ovary (CHO) gene mutation assay, the sister-chromatid exchange (SCE) test with CHO cells, unscheduled DNA synthesis (UDS) assays with primary rat hepatocytes and a dominant lethal study with Fischer 344 rats. EDA did not produce a positive, dose-related, mutagenic effect in either the CHO mutation assay or in the SCE test when evaluated both with and without the addition of a rat-liver S9 activation system. With hepatocytes, no positive effects of EDA upon UDS values were noted in 2 separate studies using either a scintillation counting procedure or an autoradiographic method to determine UDS activity. In a dominant lethal study, male rats fed for 23 weeks with dietary levels of EDA X 2HCl of 0, 0.05, 0.15 or 0.50 g/kg/day, and mated with 1 virgin female/week for 3 consecutive weeks, showed no dose-related or statistically significant effects upon fertility, total number of implantations/female, or the number of living and dead implants per female; marked effects upon the incidence of dominant lethal mutations were noted in the positive control group injected intraperitoneally with one dose of 0.25 mg/kg triethylenemelamine. We conclude that EDA was not genotoxic in the in vitro and in vivo mammalian test systems employed.

Acute and subchronic toxicity of ethylenediamine in laboratory animals

As part of a comprehensive toxicology program on ethylenediamine (EDA), acute, short-term repeated and subchronic toxicity studies were conducted. Ethylenediamine dihydrochloride (EDA X 2HCl) was used in these studies. EDA X 2HCl was slightly to moderately toxic to laboratory rats, mice or rabbits in the following acute tests: Peroral intubation, percutaneous administration, primary skin irritation and eye injury. Following dietary inclusion of EDA X 2HCl for 7 days at up to 2.70 g/kg/day to Fischer 344 rats or B6C3F1 mice, body weight gain and some organ weights of the animals were depressed in both sexes at the highest dose level. When Fischer 344 rats were fed EDA X 2HCl at 0, 0.05, 0.25, 1.00 g/kg/day for 3 months, marked decreases in body weight gain were observed in both sexes at the highest dose level. Other dose-related effects observed in either or both sexes primarily at the highest dose level, and for some at the intermediate dose level, included organ weight changes and alterations in some clinical chemistry, hematology and urinalysis parameters. No deaths occurred during the exposure period, nor were there any significant gross lesions in any of the animals. Histologic findings indicate a dose-related increase in hepatocellular pleomorphism and mild hepatocellular degeneration.

Teratogenesis and low copper status resulting from triethylenetetramine in rats

The teratogenicity of triethylenetetramine (TETA) was studied using the Sprague-Dawley rat. TETA was fed during pregnancy at levels of 0 (control), 0.17, 0.83, or 1.66% in a complete purified diet. The frequency of resorptions and the frequency of abnormal fetuses at term increased with increasing levels of the drug. Maternal and fetal tissue copper levels were significantly lower in the TETA groups than in controls, with levels decreasing in a dose-related manner. Maternal kidney and fetal liver zinc levels increased within the TETA groups in a dose-related manner. Maternal liver iron was increased in the high-dose group compared to controls. Fetal iron concentration and maternal and fetal manganese level were not significantly affected by the drug. These results show that TETA can be a teratogenic agent. Furthermore, the results suggest that the teratogenicity of the drug may be due in part to induction of copper deficiency, and perhaps through induction of zinc toxicity.

The effect of copper supplementation on the teratogenic effects of triethylenetetramine in rats

Previous research from this laboratory has shown that triethylenetetramine (TETA) fed to rats throughout pregnancy at 0.83% or 1.67% of the diet is teratogenic and results in low copper and high zinc levels in material and fetal tissues. These results suggested that the teratogenic effects of TETA were due to copper deficiency and/or zinc toxicity induced by the drug. In the present study, dams were fed TETA in a control (5 micrograms copper/gm) or copper supplemented (50 micrograms copper/gm) diet throughout pregnancy. Fetuses were removed on day 21 of gestation and examined for abnormalities. Copper supplementation reduced the teratogenicity of TETA; the reduction was correlated with an increase in maternal and fetal tissue copper levels. Copper supplementation did not alter the effects of TETA on tissue zinc levels. Thus TETA teratogenicity appears to be due primarily to induced copper deficiency, which may be reduced by dietary copper supplementation.

Chemical and biological studies of Tc-99m N,N'-bis(mercaptoacetamido)-ethylenediamine: a potential replacement for I-131 iodohippurate

The tetradentate chelating agent N,N'-bis(benzoylmercaptoacetamido)ethylenediamine was synthesized for evaluation as a potential technetium-99m renal-function radiopharmaceutical. Complexes were prepared using different reducing agents and analyzed by high-performance liquid chromatography. Biological studies were performed in mice, rats, and rabbits and indicated that the new agent is cleared by the kidneys significantly faster than Tc-99m DTPA (p less than 0.01) and slightly slower than I-131 o-iodohippuric acid (p greater than 0.05). There was no evidence of significant renal retention. Renal excretion in all species studied was 70--75% of the injected dose in 30 min; biliary excretion in rats was 7% in animals with normal renal function and 18% in 90 min in the absence of renal function. We conclude that limited clinical trials are warranted.

Central action of Craviten (M-71)

Craviten (M-71) or 2S, 2'S) N, N'-dimethyl-N, N'-bis [1-(3', 4', 5' -trimethoxy-benzoyloxy)-butyl-2]-ethylenediamine dihydrochloride an agent with a strong antiarrhythmic action has practically no effect on the central nervous system of rats and mice. It exerts no effect on the spontaneous motor activity, on amphetamine-stimulated hyperactivity, on rota-red performance, it has no analgesic and anticonvulsant action and does not change the hexobarbital sleeping time. No effects of Craviten were observed on the body temperature in rats and mice. It decreased the arterial blood pressure in rats and stimulated slightly respiration. The hypotensive effect was dose-dependent. The LD50 of the preparation is: rats: 142 mg/kg ip, 15 x 8 mg/kg iv; mice: 550 mg/kg ip; rabbits: 5 x 1 mg/kg iv.

The chronic toxicity of the preparation M-71 (Craviten)

The studies of chronic toxicity of the preparation M-71 (Craviten) were carried out on rats and mice. The body weight, absolute and relative weight or organs, haematocrit, the number of erythrocytes and leukocytes, the proportional content of leukocytes, OB value, activity of aminotransferases (AspAT and AlAT), the level of glucose in the blood serum and the histopathology of some organs were investigated. Moreover, in rats receiving M-71 intraperitoneally, the amount of electrolytes and the daily excretion of urine was studied. The results suggest that M-71 did not change the investigated parameters.

Iron tissue and excreta changes induced by ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) in dogs

The use of EDBPHA as a potential iron chelator in cases of hemochromatosis provided impetus for investigating its toxicology. Because a reddish coloration of excreta was observed during subchronic administration of the drug to dogs, measurements of iron concentrations in blood, excreta, and hematopoietic tissues were made. Groups of beagle dogs of both sexes were injected i.v. with EDBPHA doses of 6, 12, or 18 mg/kg or were given capsules containing doses of 30, 100, or 240 mg/kg for 14 days. Control dogs received either saline i.v. or empty gelatin capsules orally. In addition to the monitoring of toxicological effects, iron levels in plasma, urine, feces, liver, spleen, and kidney were monitored before drug, at the end of treatment, and after a 16-day recovery period. In the absence of hemoglobin and hematocrit changes, i.v. EDBPHA reduced renal iron 40% and hepatic iron 15% to 25% without altering splenic iron. Serum iron rose 34% to 54%, urinary iron 80% to 119%, and fecal iron 23% to 41%. Oral EDBPHA did not induce changes in tissue iron or excreta iron, but serum iron was increased 22% to 29%. These alterations in iron concentrations were transient and may be related to iron redistribution and inactivation of drug by liver.