Immunologic studies of poisonous Anacardiaceae: oral desensitization to poison ivy and oak urushiols in guinea pigs.

Poison ivy and oak urushiols or their components were compared with the respective esterified derivatives for efficacy in oral desensitization of Hartley guinea pigs sensitized to urushiols. The esterified derivatives produced a significantly greater degree of hyposensitization than did free urushiol counterparts. Suppression produced by esterified urushiols was of longer duration than that produced by free urushiols. Groups of sensitized guinea pigs were given high (100 mg/kg) or low (10 mg/kg) doses of a mixture of acetylated, saturated urushiol congeners over a 1-, 2-, or 3-week period. High doses produced a greater degree of hyposensitization regardless of the dosage schedule used. Low doses did not produce significant hyposensitization unless given over a shorter (1 week) schedule. Large single booster doses (33 mg/kg/week) of the acetate derivatives produced a rebound in responsiveness when given, 2 weeks following the last dose of the initial series, to animals hyposensitized with 10 mg/kg. No such rebound in sensitivity occurred in animals given a series of high initial doses.

Immunologic studies of poisonous Anacardiaceae: I. Production of tolerance and desensitization to poison Ivy and oak urushiols using esterified urushiol derivatives in guinea pigs.

The development of contact sensitivity to poison ivy urushiol in Hartley guinea pigs was inhibited by i.v. injection of the diacetate esters of poison ivy and oak urushiols into guinea pigs 2 weeks prior to attempted sensitization with homologous antigen. Immune tolerance to urushiols of poison ivy and oak developed in 80% or more of the treated animals and persisted for the duration of the study, 8 weeks. The tolerance was immunologically specific for urushiols since the tolerant animals were sensitizable to the unrelated sensitizer 2, 4-dinitrochlorobenzene. Guinea pigs already sensitive to urushiol were also desensitized or hyposensitizied by i.v. injection of urushiol acetates in successively increasing doses. After receiving the equivalent of 16 mg of poison ivy and oak urushiols in the acetate form over a period of 12 weeks, 54% of a group of guinea pigs were desensitized to poison ivy. all of the remaining 46% of the guinea pigs still sensitive to poison ivy were substantially hyposensitized (no longer responded to 1.5 or 0.80 microgram test doses of PDC). A control group of guinea pigs was not hyposensitized by injection of vehicle, and remained highly sensitive throughout the 15 week study. The majority of treated animals (less than 80%) were also hyposensitized to poison sumac and cashew nut shell liquid allergens.

Analogues of poison ivy urushiol. Synthesis and biological activity of disubstituted n-alkylbenzenes.

The total synthesis of different isomers and analogues of poison ivy urushiol is described. These include the positional isomers 1-5 and the nitrogen-containing analogues 6 and 8 and their mesylamino derivatives 7 and 9. 3,4-Dimethoxybenzaldehyde, m-dimethoxybenzene, resorcinol, and p-dimethoxybenzene were used as starting materials for compounds 1, 2, 3, and 4, respectively. Compound 5 is prepared by catalytic hydrogenation of bilobol isolated from Ginkgo biloba. Compounds 6 and 7 were prepared from anacardic acid as the starting material while compounds 8 and 9 were prepared from phenol as the starting material. Compounds 1-9 were tested for their ability to cross-react with poison ivy urushiol in sensitized guinea pigs. Compounds 6 and 8 were reactive at the 10-microgram dose level when applied topically, while compound 1 was a skin irritant at that dose. On the other hand, compounds 2-5, 7, and 9 showed no cross-reactivity up to the 30-micrograms dose level. Structural requirements for cross allergenicity are discussed.

Conformational aspects of the antifibrillatory activity of procaine.

The effects of procaine and four semi-rigid conformational analogs (compounds 1,2,3 and 4) were tested and compared on isolated rabbit atria. Procaine and the four analogs produced positive inotropic effects at all dose levels tested. The antifibrillatory activity of procaine and its analogs arranged in decreasing order of activity was compound 4 greater than 3 greater than 2 greater than 1 greater than procaine. The antifibrillatory activity of the compounds correlated to the distance between the ring nitrogen and the ester oxygen; that is, as the N-O distance increased the concentration required to reduce the following frequency decreased. However, the compound became more toxic as the N-O distance increased. Our data do not confirm the commonly regarded direct relationship between local anesthetic activity and antifibrillatory activity of procaine. Differences in activity displayed by the isomers of procaine could reflect differences in the ability of these analogs to bind to receptors responsible for the respective actions.

Toxicological evaluation of poison oak urushiol and its esterified derivative.

Poison oak urushiol was compared with its esterified derivative for toxicity after oral administration to rats and guinea pigs. No hematological or pathological changes were noted and there were no differences seen in clinical chemistry measurements when compared to clinical biochemical and hematological reference values of normal experimental animals. Comparative LD50 studies in mice and tissue reactivity studies in rabbits indicated that acetylated urushiols were substantially less toxic than free urushiols. However, neither poison oak urushiol or poison oak urushiol acetate appeared to produce any tissue toxicity not related to a direct irritant effect. The free urushiol produced a much greater degree of skin irritation than did the urushiol acetate. Whether or not an animal had been sensitized to urushiol apparently had no effect on organ toxicity.

Cutaneous irritation in the topical application of 30 antineoplastic agents to New Zealand white rabbits.

Of 30 antineoplastic agents studied for their primary irritation potential in rabbits, 9 showed some potential for irritation. Five of these 9 agents produced a significant dermal irritation. None of the irritation observed was considered to be irreversible skin damage. The study further showed a strong correlation between irritation observed by the Draize method and acute inflammation evaluated histopathologically. There was a tendency toward increased epidermal thickness of irritated skin sites. None of the agents produced gross or microscopically visible lesions in the internal organs observed.

Allergenic properties of naturally occurring cannabinoids.

The guinea pig maximization test was used to determine the potential of seven cannabinoids to produce allergic contact dermatitis. delta 9-Tetrahydrocannabinol and cannabinol were found to be extreme (Grade V) sensitizers. Cannabidiol, delta 8-tetrahydrocannabinol, and cannabichromene were moderate (Grade III) sensitizers. Cannabigerol and cannabinol methyl ether were not sensitizers. Most of the cannabinoids were found to be allergenically cross-reactive. Additionally, it was shown that the presence of a free 1'-hydroxyl group was required for sensitization, but not to elicit a response in sensitive animals.

Synthesis and antiallergenic properties of 3-n-pentadecyl- and 3-n-heptadecylcatechol esters.

A synthetic procedure is described for the preparation of 3-n-pentadecyl- and 3-n-heptadecylcatechols and their acetate and alaninate esters. The Wittig reagent prepared from 2,3-dimethoxybenzyltriphenylphosphonium bromide (III) was coupled with 1-tetradecanal or 1-hexadecanal to give the olefins IV and V, respectively. Catalytic reduction of IV and V followed by demethylation with boron tribromide afforded VIII and IX. The acetates were prepared using acetic anhydride and pyridine, while the alaninates were prepared using N-(tert-butoxycarbonyl)-L-alanine and dicyclohexylcarbodiimide followed by removal of the tert-butoxycarbonyl group with hydrogen chloride gas. The esters were active in guinea pigs in the production of tolerance and desensitization or hyposensitization to poison ivy-type contact dermatitis.

Immunological studies of poisonous anacardiaceae: production of tolerance in guinea pigs using 3-n-pentadecylcatechol-"modified" autologous blood cells.

The development of contact sensitivity to poison ivy urushiol in guinea pigs was prevented by intravenous injection of 3-n-pentadecylcatechol (I) coupled to autologous blood cells. Hartley, line-bred, guinea pigs were treated with pentadecylcatechol-"modified" blood cells or sham-treated blood cells 2 weeks prior to attempted topical sensitization with I. Skin testing of all guinea pigs with 3-, 1-, and 0.3-microgram doses of I applied in 5 microliter of acetone to abdominal skin sites was begun 2 weeks after attempted sensitization and repeated at 2- or 4-week intervals thereafter for 6 months or until study termination. Profound tolerance to I was observed at all skin testing intervals in the group receiving haptenated red cells and did not weaken with time. Contact sensitivity to I in control animals, however, waned with time; the study was terminated at 6 months because of the low sensitivity level of the control animals at that period. Complete or partial tolerance was induced in approximately 80% of the treated animals. The immune tolerance obtained by the single injection of pentadecylcatechol-associated red blood cells was of long duration and urushiol specific. This treatment also conferred tolerance to three unsaturated congeners of I. The allergenic potencies of the pentadecylcatechols declined with increasing saturation of the alkyl side chain. Binding studies using tritiated pentadecylcatechol showed that 81% of the activity incorporated into the red cell was membrane associated and that 19% was cell sap associated.

Biological effects of nonalkaloid-containing fractions of Erythroxylon coca.

Water soluble nonalkaloid fractions of Erythroxylon coca were screened in mice for their effects on oxygen utilization and central nervous system (CNS) activity. The fractions were screened in dogs for cardiovascular, blood glucose, and respiratory changes. No CNS effects were demonstrated in mice; however, there was a reduction in the oxygen utilization rate. Intravenous administration of the extract to dogs produced hyperglycemia, a reduction in heart rate, and a decrease in blood pressure. No substantial change in the respiratory rate and tidal or minute volumes were observed.

Immunological studies of poisonous anacardiaceae: effect of vehicle on absorption of 3-n-pentadecylcatechol and its diacetate ester derivative after oral feeding in rats.

Tritium-labeled 3-n-pentadecylcatechol and its diacetate ester were fed to Sprague-Dawley rats. Both compounds were dissolved in ethanol and in corn oil vehicles and administered by gavage. The rats were placed in metabolic cages, and the urine and feces was determined by liquid scintillation counting, and the percentage of the administered dose was utilized as a measure of absorption. While there was no difference between the absorption of either compound, absorption was affected by the vehicle. Approximately 30% of the administered radioactivity appeared in the urine when ethanol was the vehicle, but about half that amount (14%) was excreted in the urine when the compounds were dissolved in corn oil. A subsequent bile cannulation study showed that the balance of the radioactivity found in the feces was not a result of biliary excretion. The majority of the activity recovered from urine and feces was eliminated within 48 hr after dosing. These data indicate that oil is a poor vehicle for GI absorption of urushiol components.

Spectrophotometric evaluation of carboxyhemoglobin in blood of mice after exposure to marijuana or tobacco smoke in a modified Walton horizontal smoke exposure machine.

Carboxyhemoglobin (COHb) values were determined in mice exposed to varying amounts of marijuana and tobacco cigarette smoke utilizing a spectrophotometric technique. Mice were exposed to smoke inhalation in a modified Walton horizontal smoke exposure machine, whereby rodents can be exposed to multiples of 1-min smoke exposure cycles. Smoke exposure was intermittent; during the first 30 sec of each 1-min cycle, the subjects were exposed to smoke diluted either 1:10 or 1:5 with air. During the second half of the cycle the animals were given fresh air. There was a positive linear relationship between COHb values obtained and the number of puffs of marijuana smoke administered via either 2, 4, 6, or 8 "puffs" of marijuana smoke. COHb levels in plasma did not increase in animals given multiple 8-puff episodes of smoke daily as long as a 60-min period was interposed between smoking episodes. COHb values in mice exposed to tobacco smoke were significantly higher than those in mice receiving equal numbers of exposures to marijuana smoke. Mean COHb values of mice receiving 8 consecutive puffs of marijuana smoke were 18.6 and 22.0% saturation, but CO was rapidly cleared from the blood. This rapid clearance suggests that the binding affinity of CO for mouse hemoglobin may be be weaker than that of human hemoglobin. Mice similarly exposed to 6 or 8 puffs of tobacco smoke had mean COHb values of 24.6 and 28.5% saturation, respectively. No acute lethal effects were observed in mice receiving multiple daily episodes of 8 puffs per episode of marijuana smoke, whereas mice exposed to a single 8-puff episode of tobacco smoke suffered about 50% acute lethal effects.

The effect of marijuana smoke exposure on murine sarcoma 180 survival in Fisher rats.

Fisher rats were treated for 28 or 60 days to multiple exposures to the smoke of marijuana or marijuana placebo cigarettes. Primary, secondary and in some instances tertiary tumor implants were performed. Murine sarcoma 180 tumor cells (7.5 x 10(7)) were implanted subcutaneously on day 1, 14 and 28 following initiation of smoke exposure (28 day studies) or on day 1, 14 after cessation of smoke exposure (60 day studies). Tumor areas were measured on alternate days beginning on the second or third day after implantation for 13 or 14 days. Exposure to both marijuana and placebo smoke for 28 days (6, 9 and 18 cigarettes per day) resulted in suppressed growth of secondary and tertiary implants. Administration of delta 9 tetrahydrocannabinol (50 mg/kg, i.p., 20 days) failed to suppress the growth of primary and secondary tumors. This suggests that noncannabinoid constituents of the smoke may contribute to the suppression of tumor growth. Exposure of rats to 9, but not 4 or 6, marijuana or placebo cigarettes per day for 60 days suppressed the growth of primary but not secondary tumors. Thus, the effects of smoke exposure appear to be lost by two weeks after cessation of treatment. The possible existence of a non-cannabinoid immunostimulant in the smoke is discussed.

The effect of subacute marijuana smoke inhalation on experimentally induced dermonecrosis by S. aureus infection.

Dermonecrosis was induced in ICR mice by subcutaneous implantation of Staphylococcus aureus absorbed onto sterile cotton pellets. This model was used to assess the effects of marijuana smoke, marijuana placebo smoke and delta 9-tetrahydrocannabinol (delta 9-THC) on the local immune response to bacterial infection. Mice were exposed to 40 or 80 "puffs" of marijuana smoke, marijuana placebo smoke or air daily for 4 consecutive days. The estimated dose of delta 9THC per day generated from 40 or 80 puffs of marijuana smoke was 3.2 and 6.4 mg/kg, respectively. A group of sentinel (Shelf) control mice were included in each experiment. The necrotic index (NI) of mice exposed to 40 or 80 puffs of marijuana smoke were 67% and 44% of control, respectively. Air exposed mice showed a necrotic index comparable to the shelf control group. In chronically (60 days) exposed mice (80 puffs per day) the necrotic index was about 12% of control, while air-exposed mice were about 40% of control. Placebo marijuana smoke exposed mice had a NI comparable to that of marijuana smoke exposed mice which suggested that the reduction in NI was unrelated to the pychomimetic component delta 9THC. To further explore which of the constituents of marijuana were responsible for the decreased NI, the ethanol extract from marijuana leaves was partioned between water (cannabinoid free) and chloroform (cannabinoid rich). Injection of the cannabinoid free fraction produced comparable decrease in the NI as observed with whole marijuana smoke, while the cannabinoid rich fraction produced no effect. delta 9THC at a dose of 10 mg/kg per day did not alter the NI.

Single dose parenteral hyposensitization to poison ivy urushiol in guinea pigs.

Studies were carried out in guinea pigs to evaluate the potential for single dose hyposensitization to poison ivy urushiol dermatitis. Sensitization was induced by topical application of 1 mg of poison ivy urushiol to the back of the neck. In the first series of studies, three different analogs of poison ivy urushiol were studied: 1) a mixture of pentadecyl and heptadecyl catechols (PDC/HDC), the saturated side chain analog of the natural urushiol mixture; 2) a mixture of the diacetate esters of PDC and HDC (PDC/HDC Ac), the esterified form of the saturated sidechain analogs; 3) 2-n-pentadecyl hydroquinone diacetate (HQ Ac). Each of these compounds was administered as 5 mg of the free catechol i.m. each week for three weeks. A vehicle group received only corn oil injections. Reactivity to poison ivy urushiol (PIU) challenge was evaluated in skin tests at 1 and 5 weeks post-treatment. PDC/HDC Ac induced a marked reduction in both the incidence and the severity of lesions induced by PIU at both 1 and at 5 weeks post-treatment. Other analogs were ineffective at 5 weeks post-treatment, and were less effective than PDC/HDC Ac at 1 week post-treatment. In a second series of experiments, the efficacy of PDC/HDC Ac was evaluated in both single and multiple dose regiments. One treatment group received 5 mg of PDC/HDC Ac intramuscularly each week for 4 weeks, while another treatment group received a single dose of 20 mg PDC/HDC Ac i.m. Corresponding vehicle control groups were also included. At 1 week post-treatment in the single dose group, the PDC/HDC Ac was only modestly effective, with some reduction of severity of lesions at the higher challenge doses of PIU. However, at 4 and 7 weeks post-treatment, both the incidence and the severity of the lesions at all challenge doses were reduced. In the multiple dose group, the incidence and severity of lesions are reduced at 1 week and 4 weeks post-treatment (4 weeks and 7 weeks after the initial dose) but were not significantly different from the single dose group. These findings indicate that the diacetate ester of PDC/HDC is an effective hyposensitizer to poison ivy urushiol, and that this hyposensitization can be reasonably accomplished in a single dose treatment regimen.

In vivo efficacy of antifungal oxoaporphine alkaloids in experimental disseminated candidiasis.

The efficacy of three antifungal oxoaporphine alkaloids, liriodenine, liriodenine methiodide, and oxoglaucine methiodide, was determined in a mouse model of disseminated candidiasis. Mice infected with a lethal dose of Candida albicans NIH B311 were administered varying doses of each drug intraperitoneally or intravenously 7 hr postinfection. Reductions in the number of colony-forming units (CFU) recovered per milligram of kidney tissue were observed in drug-treated animals compared to vehicle-treated control mice. Significance was determined by the Wilcoxon nonparametric rank sum test. Intravenous administration of both liriodenine and liriodenine methiodide resulted in a significant reduction in the number of recovered CFU, while there was no significant response to treatment with oxoglaucine methiodide.