Evaluation of Citrinin Toxicity on the Immune Functions of Mice 1

Citrinin, a nephrotoxic fungal metabolite produced by several species of Penicillium and Aspergillus , has been found to contaminate foods used by humans and animals. The present study investigated potential effects of this compound on the immune system. Male CD-1 mice received 0, 0.12, 0.6 or 3.0 mg of citrinin/kg i.p. every other day for 2-4 weeks. Food consumption and body or organ weights were not affected but kidneys were enlarged. Splenic cells from mice exposed to citrinin for 2 or 4 weeks were cultured with or without the mitogens, phytohemagglutinin (PHA), pokewecd mitogen (PWM) or lipopolysaccharide (LPS). Exposure to citrinin stimulated splenic lymphocyte proliferation. Antibody production by splenic cells in animals sensitized to sheep red blood cells (SRBC) increased in the two highest dose groups. Delayed hypersensitivity reaction, measured as a foot-pad swelling, in response to SRBC sensitization and subsequent challenge were not affected by citrinin treatment. In vitro addition of citrinin (>1 × 10^-5M) to splenic lymphocytes was cytotoxic. These findings suggest that citrinin mildly stimulates the immune system but does not have consistent immunotoxic effects at the doses tested.

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.

Persistence of vanadium compounds in lungs after intratracheal instillation in rats

Translocation and tissue distribution of two different forms of vanadium compounds, orthovanadate (soluble) and vanadium pentoxide (less soluble), were investigated. Groups of randomly selected rats were injected intratracheally with radiolabeled vanadium (48V) compounds and the animals were sacrificed at 1, 7 and 28 days after treatment. Blood, lungs and other major organs and tissues, namely liver, kidney, spleen, heart, testes, brain, muscle, and bone were sampled and the vanadium contents determined by gamma spectrometry. The less soluble form of vanadium (vanadium pentoxide) was eliminated from the lungs at a slow but exponentially linear rate, whereas the soluble form was translocated rapidly from this organ and exhibited a non-linear decline. Compared to the less soluble form, significantly less vanadium was retained in lungs 7 and 28 days after intratracheal instillation of vanadate. One day after treatment significantly higher concentrations (approximately 4 times) of vanadium after orthovanadate were observed in liver, kidney, spleen and bone compared to the pentoxide. However, tissue residues at 7 and 28 days indicated that both forms of vanadium were rapidly eliminated, except from bone and lungs. Results suggest a prolonged retention of less soluble forms of vanadium and possible health effects following repeated occupational exposure.

Alteration of humoral and cellular immunity in manganese chloride-treated mice

Immunological effects of manganese chloride (MnCl2) were determined in male CD-1 mice injected (ip) daily with MnCl2 (0, 1, 3, or 10 mg/kg) for 4 wk. Liver and spleen weights increased in the 10-mg/kg MnCl2 treatment group. The weights of thymus, kidney, and adrenal glands were not affected by MnCl2 treatment. No significant differences in peripheral erythrocyte or leukocyte counts were observed; however, packed cell volumes decreased in the medium- and high-dose groups. Manganese treatment significantly increased the uptake of [3H]thymidine (3H-TdR) by cultured splenic cells. The lymphoproliferative responses to phytohemagglutinin (PHA) and concanavalin A (Con A) increased at all levels of MnCl2 exposure. No differences in the responses to lipopolysaccharide (LPS) were observed. Mixed lymphocyte responses increased significantly with exposure to 10 mg MnCl2/kg. Another immunological alteration induced by MnCl2 was a dose-dependent immunosuppressive effect on the development of antibody-forming cells. The production of anti-sheep red blood cell antibody (alpha-SRBC) nearly ceased following exposure to 10 mg MnCl2/kg. This effect was apparently reversible, as the number of plaque-forming cells in the 10-mg/kg treatment group increased after MnCl2 treatment had been halted for 2 wk. The alpha-SRBC titer also decreased significantly in the 10-mg/kg treatment group, corresponding to the reduction of antibody producing cells. MnCl2 treatment was immunomodulatory to the reduction of antibody producing cells. MnCl2 treatment was immunomodulatory in male CD-1 mice, as indicated by the increase in mitogen and mixed lymphocyte responses and decrease in antibody production.

Effects of repeated doses of aspartame on serotonin and its metabolite in various regions of the mouse brain

Following a finding that single doses (approximating to average intakes and to potential 'over-use') of aspartame administered orally to mice caused significant increases in norepinephrine and dopamine concentrations in various brain regions, the effect of repeated exposure to aspartame was studied. Male CD-1 mice were given a daily oral dose of 0, 13, 133 or 650 mg/kg for 30 days and 1 day after the last dose the animals were decapitated and their brain regions were quickly isolated. Analyses of the different regions for catecholamine and indoleamine neurotransmitters and their major metabolites indicated that the increases in adrenergic chemicals observed shortly after a single exposure were not apparent after repeated dosing. In contrast, concentrations of serotonin and its metabolite, 5-hydroxyindoleacetic acid, were decreased in several regions. An increased supply of phenylalanine may be responsible for a decrease in tryptophan uptake by the brain tissue or for a depression in tryptophan conversion to serotonin.

Vanadate-dependent oxidation of pyridine nucleotides in rat liver microsomal membranes

An enzymatic Na3VO4-dependent system for the oxidation of reduced pyridine nucleotides in purified rat liver microsomes was characterized. The system has a pH optimum of 6.5, and appears to be specific for vanadate, since activity in the presence of a related transition metal, molybdate, was not detected. Vanadate-dependent oxidation occurred with a concomitant consumption of O2 and, contrary to previous reports, preferred NADPH over NADH. At pH 6.5, the NADPH/NADH oxidase activity ratio was greater than 2:1. Sodium vanadate-dependent oxidation of NADH was inhibited by rotenone, antimycin A, NaN3, and NaCN. Conversely, Na3VO4-dependent NADPH oxidation was slightly affected by rotenone, but was insensitive to antimycin A, NaN3, NaCN, or quinacrine. Vanadate-dependent oxidation of either pyridine nucleotide was inhibited by the addition of either superoxide dismutase or catalase, indicating that both superoxide and hydrogen peroxide may be intermediates in the process. Linear sucrose gradient purification of the microsomes showed that the vanadate-dependent system for NADPH oxidation resides primarily in the endoplasmic reticulum. These studies indicate the existence of separate and distinct enzymatic systems for vanadate-stimulated oxidation of NADPH and NADH in mammalian microsomal membranes, and argue against an exclusive role of endogenous superoxide in the process.

Portal hypertension workup by DSA

To provide information for preoperative planning, combined, selective intravenous (IV) and intraarterial (IA) digital subtraction angiography (DSA) studies were performed on 42 portal hypertension patients scheduled for portal systemic shunt procedures. Selective IV-DSA was performed to demonstrate the hepatic venous system, left renal vein, and inferior vena cava. Portal venous anatomy, direction of flow, and portal systemic collaterals were evaluated by selective IA-DSA. In addition, selective IA-DSA was performed postoperatively on 8 patients to assess shunt patency. Technically adequate DSA studies, suitable for surgical planning or postoperative assessment, were obtained in all of the 50 patients examined. Patient or internal organ motion was not a limiting factor in any study. Such use of DSA represents an efficacious, safe, and cost-effective alternative to conventional film-screen angiography for the evaluation of patients with portal hypertension.

Studies of immune function of CD-1 mice exposed to aflatoxin B1

The immunotoxic potential of aflatoxin B1 (AFB1), a secondary metabolite of Aspergillus flavus and a known animal hepatocarcinogen, was evaluated in CD-1 mice. Male mice received 0, 0.03, 0.145 or 0.70 mg/kg of AFB1 orally every other day for 2 weeks in a corn oil:ethanol vehicle. Splenic lymphocytes were cultured in the presence of lipopolysaccharide (LPS), phytohemagglutinin (PHA), or pokeweed mitogen (PWM). A dose-related inhibition of [3H]thymidine uptake in lymphocyte cultures, with or without the above mitogens, was observed after 2 weeks of AFB1 exposure. Synthesis of DNA was decreased in mixed lymphocyte cultures. Primary antibody production by splenic cells, from animals challenged with a T-dependent antigen (sheep red blood cells), was affected by AFB1. No effects were observed, however, when animals were challenged with a T-independent antigen (LPS). A dose-related suppression of a delayed-type hypersensitivity reaction to keyhole limpet hemocyanin was observed. The results suggested that AFB1 was immunotoxic in CD-1 mice.

Dose and time related effects of T-2 toxin on mitogenic response of murine splenic cells in vitro

The effects of T-2 toxin in vitro on murine splenic cells were investigated. Cells from syngeneic male NFS/N mice were cultured with three concentrations of either lipopolysaccharide (LPS), pokeweed mitogen (PWM), phytohaemagglutinin (PHA), or concanavalin A (Con A), for 48 h. T-2 toxin (10(-12)-10(-8)M) was added at the beginning or 24 h after initiation of the cultures. Exposure to T-2 toxin (10(-11)-10(-10)M) after 24 h increased 3H-thymidine uptake by splenic cells. Stimulation by PWM increased dramatically while the response to LPS was increased to a lesser extent in this system. Conversely, exposure to T-2 toxin decreased T-cell responses to both PHA and Con A. Exposing cells to T-2 toxin at the initiation of culture increased Con A stimulation; LPS and PWM responses decreased following 48 h exposure. When splenic cells were pre-treated for 60 or 90 min at 0 degrees C with 10(-9)M T-2 toxin the responses to both PWM and LPS increased. Increased 3H-thymidine uptake was also observed following 90 min exposure to T-2 toxin alone at either 0 or 37 degrees C. The increased PWM response and the mitogenic phenomenon observed when cells were exposed only to T-2 toxin were consistent with previously observed effects of in vivo T-2 toxin exposure.

Balloon dilation of the femoral vein expediting percutaneous Greenfield vena caval filter placement

A balloon angioplasty catheter was used to dilate the femoral vein puncture site before placement of a Greenfield vena caval filter in nine patients. Compared with the conventional use of serial coaxial dilators, this technique expedites filter placement with minimal trauma and bleeding at the puncture site.

Superior vena cava obstruction: evaluation with digital subtraction angiography

Superior vena cava (SVC) obstruction is an uncommon but dramatic clinical presentation that often requires immediate treatment. We present a technique for evaluation of SVC syndrome using small-gauge butterfly needles and intravenous digital subtraction angiography, and we report our results in ten patients. We find this technique superior to conventional venography since it is rapid, easy, safe, and more cost-effective to perform.

Effect of cyanogenic glycosides and protein content in cassava diets on hamster prenatal development

Cassava is a staple food for 450-500 million people in 26 tropical countries. Groups of pregnant hamsters were fed diets consisting of cassava meal:laboratory chow (80:20) during Days 3-14 of gestation. One low cyanide (sweet) cassava meal and one high cyanide (bitter) cassava meal were studied. One additional group was fed a diet which resembled cassava in nutritional value, but which lacked the cyanogenic glycosides. Thiocyanate concentrations increased significantly in the urine and blood of dams fed cassava diets. Increased tissue thiocyanate concentrations were observed in fetuses recovered from cassava-fed dams. Cassava-fed dams gained significantly less weight than did control animals and their offspring showed evidence of fetotoxicity. Reduced fetal body weight and reduced ossification of sacrocaudal vertebrae, metatarsals, and sternebrae were associated with cassava diets. High cyanide cassava diets were also associated with a significant increase in the numbers of runts compared to litters from dams fed either low protein or laboratory stock diets.

Influence of dietary supplementation with thiamine on lead intoxication in rats

The influence of dietary supplementation with thiamine on lead (Pb) contents in blood and tissues, blood δ-aminolevulinic acid dehydratase (δ-ALAD) activity, and urinary excretion of δ-aminolevulinic acid (δ-ALA) was evaluated in male Sprague-Dawley rats. Groups of randomly selected animals were given a thiamine-deficient diet, a diet containing normal thiamine (20 mg/kg), or a thiamine-supplemented diet (50 mg/kg), along with control drinking water or water containing 100 ppm Pb, for 4 mo. Animals fed the thiamine-supplemented diet (50 mg/kg) and Pb showed decreased urinary excretion of δ-ALA and a decreased inhibition of δ-ALAD activity in blood compared to those given Pb with normal thiamine diet. The liver, kidney, and blood of rats receiving supplemental thiamine also contained significantly less Pb than the other two treatment groups given Pb-containing water. The protective effect of thiamine against Pb toxicity may be attributed to its interference with retention of the metal in body tissue, possibly resulting from the formation of excretable thiamine-lead complexes.

Effects of excess dietary selenite on lead toxicity in sheep

The hypothesis that excess dietary selenite ameliorates lead (Pb) toxicosis in domestic sheep was tested. Twenty 6-8-yr-old ewes fed alfalfa pellets were assigned to the following treatments: (1) control; (2) 9.8 mg Pb/kg body weight (b.w.)/d as PbCO3; (3) 3 mg Se/animal/d as Na2SeO3·5H2O; or (4) a combination of treatments 2 and 3. The gelatin-encapsulated salts were given orally. The study was terminated on d 104, by which time three animals in the Pb group and all five animals in the Pb+Se group had died. All remaining animals were slaughtered on d 104. Lead and Se concentrations were determined in six biweekly-collected blood samples and in soft tissues and bone. Sheep on the control and Se treatments had similar feed intakes, body weights, and tissue Pb levels. Those in the Pb+Se group had lower feed intake, but higher blood Pb values compared with the Pb group. Feeding either element increased (P<0.05) the concentration of that element in blood, kidney, liver, spleen, and bone. Muscle-Pb concentrations were not affected (P<0.05) by treatment. Selenium concentrations in kidney, liver, and muscle were greater (P<0.05), whereas those in heart were less (P<0.05) for the Pb+Se group than for the Se Group. Clinical signs associated with Pb toxicosis noted in other animals were not observed in the poisoned sheep in this study. Selenite did not protect sheep against Pb toxicity and likely served as a synergistic factor.

Comparative metabolism of linamarin and amygdalin in hamsters

Rates of cyanide liberation resulting from hydrolysis of the cyanogenic glycosides linamarin, amygdalin and prunasin by a crude beta-glucosidase prepared from hamster caecum were studied in vitro. In addition, hamster blood cyanide and thiocyanate concentrations were determined at 0.5, 1, 2, 3 and 4 hr after an oral dose of 0.44 mmol linamarin or amygdalin/kg body weight. Plots of cyanide liberated v. time for linamarin and prunasin yielded straight lines. A similar plot for amygdalin was curvilinear, with the rate of cyanide release increasing with time. At 10(-3) M substrate concentrations, the average rates of hydrolysis of prunasin, amygdalin and linamarin were 1.39, 0.57 and 0.13 nmol/min/mg protein, respectively. Lineweaver-Burk plots yielded apparent Km and Vmax values of 3.63 X 10(-5) M and 0.35 nmol/min/mg protein, respectively, for amygdalin, and 7.33 X 10(-3) M and 1.04 nmol/min/mg protein, respectively, for linamarin. Blood cyanide concentrations following amygdalin treatment reached their highest level (130 nmol/ml) 1 hr after dosing and remained elevated until 3 hr after treatment. Blood cyanide concentrations following linamarin treatment reached their highest level (116 nmol/ml) after 3 hr and then declined immediately. Area under the blood cyanide concentration-time curve was 395 nmol-hr/ml for amygdalin and 318 nmol-hr/ml for linamarin. The results suggest a faster rate of enzymatic hydrolysis and cyanide absorption for amygdalin than for linamarin.

Neurobiochemical alterations induced by the artificial sweetener aspartame (NutraSweet)

The dipeptide aspartame (NutraSweet) is a newly approved and widely used artificial sweetener in foods and beverages. Consumption of aspartame (ASM) has been reported to be responsible for neurologic and behavioral disturbances in sensitive individuals. Unfasted male CD-1 mice were dosed orally with 13, 130, or 650 mg/kg ASM in corn oil, while control animals received corn oil alone. Three hours after dosing, the animals were killed, and the concentrations of the catecholamines norepinephrine (NE) and dopamine (DA), catecholamine metabolites 3-methoxy-4-hydroxymandelic acid (VMA), homovanillic acid (HVA), and dihydroxyphenylacetic acid (DOPAC), the indoleamine serotonin (5-HT), and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were determined by electrochemical high-performance liquid chromatography in six brain regions. ASM exerted its primary effect on adrenergic neurotransmitters in various brain regions. In the hypothalamus, the region richest in NE, increases in NE concentrations of 12, 49, and 47% were found in the low, medium, and high dose groups, respectively, relative to control. Significant increases of NE in the medulla oblongata and corpus striatum were also observed. Increases of the catecholamine DA and catecholamine metabolites VMA, HVA, and DOPAC were seen in various regions. The indoleamine serotonin and its metabolite 5-HIAA were unaffected by ASM treatment. These findings are consistent with ASM-induced increases in the brain catecholamine precursor amino acids phenylalanine and tyrosine, as reported earlier. Such observed alterations in brain neurotransmitter concentrations may be responsible for the reported clinical and behavioral effects associated with ASM ingestion.

Influence of 2,5-hexanedione on rat brain amine synthesis and metabolism

Sprague-Dawley derived rats were gavaged with daily doses of 2,5-hexanedione, a neurotoxic metabolite of both methyl n-butyl ketone and n-hexane. Seven daily doses of 0, 30, 100 or 300 mg 2,5-hexanedione/kg caused neuromuscular incoordination at the highest dose level while no effect was seen at the lowest level. Intravenous injections of either tritiated tyrosine or tryptophan, followed by exact time-interval sacrifices, facilitated the determination of synthesis rates and metabolism of various brain amines. At a cumulative dose of 210 mg 2,5-hexanedione/kg, the dopamine turnover rate was significantly increased, while precursor and metabolite levels were unchanged. Levels of serotonin as well as the serotonin synthesis rate remained unchanged, but levels of 5-hydroxyindoleacetic acid increased significantly in a dose dependent manner. The rise in 5-hydroxyindoleacetic acid levels inconjunction with no effects on other indoleamione parameters in 2,5-hexanedione-fed animals, suggests a possible inhibition of the energy-dependent 5-hydroxyindoleacetic acid efflux system in the brain.

Creeping Eruption At an Unusual Site

A 9 year old female child developed creeping eruption on the neck which is an unusual site.

Effects of dietary vanadium exposure on levels of regional brain neurotransmitters and their metabolites

Adult male CD-1 mice were treated with various levels of vanadate in drinking water for 30 days. The levels of catecholamine and indoleamine neurotransmitters and their major metabolites were measured in six different brain regions. Vanadium caused a dose-related decrease in norepinephrine (NE) levels in hypothalamus, the region rich in this biogenic amine. Levels of the NE metabolite, vanillylmandelic acid (VMA), correspondingly decreased in the same region. Although hypothalamic dopamine (DA) also showed a significant decline, vanadium had little effect on DA metabolites. Levels of 5-hydroxytryptamine (5-HT) and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were not influenced. Levels of DA were not affected in the corpus striatum, where the highest levels of this amine are observed. Effects of vanadium on various biogenic amines and their metabolites were only marginal in other brain regions. Results suggest that vanadium has a selective effect on adrenergic pathways, and effects on other hypothalamic amines appear to be secondary. These observations support the pro-oxidant potential of vanadate ion on catecholamines suggested earlier.

Pulmonary clearance of soluble and insoluble forms of manganese

Manganese is an essential metal of toxicologic concern primarily because of exposure via inhalation. Environmental forms of Mn exist mainly as insoluble oxides, yet much of the research information available relates to the soluble salts. In the present study, adult male Sprague-Dawley rats were intratracheally instilled with either soluble MnCl2 or insoluble Mn3O4 labeled with 54Mn. Lungs and other major organs were sampled over a span of 3 mo after dosing with the respective chemicals, which were equivalent to 8 mu Ci and 1 mumol of manganese in 0.2 ml of buffer. There was rapid clearance of Mn from the lungs in the case of both chemicals; the chloride cleared at an initial rate of nearly four times that of the oxide. Despite this early difference, the amount of 54Mn remaining in the lungs after 2 wk was similar for both compounds. The level of 54Mn in the liver, kidney, spleen, and testes peaked at the 3-d sampling point in the case of the oxide, whereas the chloride peaked in these organs within 4 h. At 1 wk after administration, however, the 54Mn activity was comparable for both compounds in most organs sampled. Mn uptake in the brain was also more rapid with the chloride form, but both compounds remained at high levels for several weeks.

Vanadium accumulation and subcellular distribution in relation to vanadate induced cytotoxicity in vitro

A bovine kidney cell culture system was used to assess the relationship of vandium uptake and subcellular distribution to orthovanadate induced cytotoxicity. Twenty-four hr incubations with 20-1000 microM vanadium elicited 15-75% cytotoxicity. Concentration-related morphological changes from the control polygonal shape to the treated biopolar appearance were detected. Vanadium accumulated in cells via a multiphasic process; peak accumulation was achieved by 1 hr post-treatment and was followed by apparent decline, completed by 3 hr. A slower second phase of accumulation occurred during the remainder of the 24 hr incubation period. A concentration-dependent accumulation resulted in a 50-fold increase in cellular vanadium content. Near maximum toxicity was achieved at a cellular vanadium burden of approximately 5 nmoles/10(6) cells; further accumulation (up to 35 nmoles/10(6) cells) resulted in only a slight increase in the degree of toxicity. Subcellular distribution studies indicated 90% accumulation of vanadium in the soluble supernatant fraction (105,000xg supernatant) at varying stages of cytotoxicity. It was concluded that the multifaceted dependency of vanadium cytotoxicity on its cellular content may have resulted from a cellular balancing between proposed regulatory functions for vanadium and the interactions incurred with an excessive content.

Effect of repeated dietary exposure of aflatoxin B1 on brain biogenic amines and metabolites in the rat

Male Sprague-Dawley rats were treated po twice weekly for 3 weeks with a low (32.8 micrograms/kg) and high dose (327.9 micrograms/kg) of aflatoxin B1 (AFB1) in corn oil. A control group received corn oil only. At the end of the experiment the rats were killed, and the concentrations of the brain catecholamines, norepinephrine (NE) and dopamine (DA), catecholamine metabolites, 3-methoxy-4-hydroxymandelic acid (VMA), homovanillic acid (HVA), and dihydroxyphenylacetic acid (DOPAC), and the indoleamine serotonin (5-HT) and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were determined by high-pressure liquid chromatography in five brain regions. The major effects were found in striatal dopamine and serotonin concentrations, with decreases of 37 and 29%, respectively. A corresponding decline was observed in the dopamine metabolites, homovanillic acid (44%) and dihydroxyphenylacetic acid (30%). Concentrations of these neurotransmitters and metabolites were only marginally altered in cerebral cortex, cerebellum, hypothalamus, and medulla oblongata. It appears that a major effect of AFB1 is on dopaminergic pathways, possible by selectively perturbing the conversion of tyrosine to biogenic catecholamine neurotransmitters.

Clearance and excretion of intratracheally and orally administered aflatoxin B1 in the rat

The pharmacokinetic disposition of intratracheally (i/t) and orally administered [3H]AFB1 was studied in male Sprague-Dawley rats. Blood, urine and faeces were collected at selected intervals following administration of a single i/t or oral dose of AFB1 (600 micrograms/kg) in saline. Blood-concentration data from both groups approximated a two-compartment open model. The time-to-peak for the i/t group (hr) was less than that for the oral group (3 hr), but the disappearance of label from the blood followed a nearly identical course in both groups. The plasma half-lives (t1/2) were 87.7 and 91.8 hr for the i/t and oral groups, respectively. In addition, urinary and faecal excretion profiles were similar. By day 23, urinary excretion of label had accounted for 16.4 and 15.0% of the dose in the i/t and oral groups, respectively, and faecal excretion for 56.0 and 54.6%. At this time, however, significantly more label was recovered from the lungs and upper airways of the rats of the i/t group than in those treated orally.

Short term disposition of soluble vs. insoluble forms of cadmium in rat lung after intratracheal administration: an autoradiographic assessment

An autoradiographic study was undertaken to compare the initial distribution patterns of soluble and less soluble forms of cadmium in the rat lung after intratracheal (i.t.) instillation. Male Sprague--Dawley rats were divided into 2 groups, each group received either soluble or a less soluble cadmium (109Cd) i.t. in 0.1 ml buffered saline. At 5, 30 and 90 min post-instillation, rats were sacrificed and processed for autoradiography, and radioactivity estimation of lung sections. 109Cd was unevenly distributed in the lungs at 5 min for both forms of Cd. At 90 min post-instillation, 109Cd was almost evenly distributed in the lung instilled with the soluble form; in case of the less soluble form a spotty distribution of 109Cd in the bronchi was observed. 109Cd was mainly translocated to the liver and stomach, followed by the kidney and intestine. It is apparent that the initial translocation of instilled 109Cd from the lung is relatively slow in the case of less soluble form as compared with the soluble form.

Cytotoxicity-related alterations of selected cellular functions after in vitro vanadate exposure

A bovine kidney cell line was used to monitor select cellular functions for toxicity-dependent alterations in an effort to examine the cellular response to vanadium insult. The vanadium concentrations utilized ranged between 20 and 500 microM Na3VO4 (V) and elicited 15-60% cytotoxicity. Cytotoxicity-related decreases in thymidine incorporation into DNA and leucine incorporation into protein were noted. Paradoxically, V-treated cultures exhibited increased protein and DNA content, suggestive of a decrease in precursor transport. K+-dependent phosphatase (KP), acid phosphatase (AP) and succinate dehydrogenase (SDH) were monitored in surviving cells and in a cell-free system. Significant inhibitions were detected for KP and AP; SDH exhibited slight enhancement. In the cell-free system, KP was inhibited significantly at 10(-7) M V, while AP and SDH were either unchanged or sensitive only at concentrations of 10(-4) M V or greater. Measurement of reduced glutathione (GSH) in surviving cells revealed toxicity-dependent increases of up to 500% of control values. When compared to the cellular V content, the GSH:V molar ratio decreased from 1.7 to 0.5 as cell survival decreased.

In vitro and in vivo effects of vanadate on K+-dependent phosphatase activities from subcellular fractions of brain, kidney and liver

Inhibition of K+-dependent phosphatases by sodium orthovanadate was studied in the subcellular fractions of brain, kidney and liver from male Sprague-Dawley rats. The concentration required to produce an in vitro phosphatase inhibition of 50% ranged from a low of 0.2 microM in the kidney 900 X g fraction to a peak of 400 microM in the brain soluble fraction. The concentrations required to produce 50% inhibition occurred in the micromolar range for most fractions studied. Injection of sodium vanadate (i.p., 8 mg/kg) produced phosphatase inhibition in several of the fractions, but not as pronounced as the in vitro treatment. The results indicate that vanadate is a potent inhibitor of phosphatase activity in vitro, and may have similar potential in vivo.

Mycotic aneurysms in intravenous drug abusers: the utility of intravenous digital subtraction angiography

Two-hundred thirteen intravenous digital subtraction angiographic (DSA) examinations were performed on 195 intravenous drug abusers to rule out the possibility of a mycotic aneurysm in a groin, neck, or upper extremity infection. Twenty-three surgically proved cases of mycotic aneurysm were correctly identified with no false positive results. In addition, six cases of major venous occlusion were documented. We present the results of our experience and conclude that DSA is an effective and cost-efficient method of examining this high risk patient population.

Developmental toxicity of the cyanogenic glycoside linamarin in the golden hamster

Cassava, a staple food in many tropical countries, has been suspected as a cause of human congenital defects. Ingestion of the material during pregnancy has been reported to induce limb defects, microcephaly, open eye, and growth retardation in rats. Linamarin is a natural cyanogenic glycoside that occurs in high concentrations in cassava. In the present study, pregnant hamsters received an oral dose of 70,100, 120 or 140 mg/kg linamarin or an equivalent volume of isotonic saline during the early primitive streak stage of gestation. A dose of 120 or 140 mg/kg of the glycoside was associated with an increased incidence of vertebral and rib anomalies as well as the production of encephaloceles in the offspring. These larger doses of linamarin also resulted in obvious maternal toxicity. Linamarin treatment had no effect on fetal body weight, ossification of fetal skeletons, embryonic mortality, or litter size. Although ingestion of the cyanogenic glycoside was associated with a significant teratogenic response, the effects occurred only at doses that elicited signs of maternal intoxication.

Cranioschisis aperta with encephaloschisis in cephalothoracopagus hamster twins

The results of gross and histopathological study of a near-term male hamster exencephalic lateral cephalothoracopagus are presented. There was minimal duplication of the internal organs to the point of division at the abdomen. The appendicular skeleton was relatively unaffected by the severe malformations of the axial skeleton. The studies suggested that the lateral relationship of the skull to the spinal columns was a consequence of the presence of two embryonic neural tubes; the chordomesodermal systems of the right and left twins apparently contributed the tissues for the right and left cephalic neural folds, respectively. Anomalies of the vertebral bodies and neural arches were not related to failure of closure of the neural tube as there was no evidence for rachischisis in either body half. Rather, the anomalous axial skeletal elements were apparently the result of competing fields of development by two chordomesodermal systems. The twins were recovered from a dam maintained on a diet consisting of 80% cassava, a cyanide-containing staple consumed by humans in tropical countries. Because the numbers of resorbed implantation sites and malformed litermates were low and the failure to produce conjoined twins in other litters recovered from dams given cassava diets, it appears unlikely that the malformation was related to the composition of the diet.

Cytotoxicity related changes in biochemical cell function following in vitro cadmium treatment

In an effort to examine cellular responses to cadmium insult a bovine kidney cell line was used to monitor select cell functions for toxicity related alterations. Cadmium concentrations used ranged between 0.2 and 2.5 microM CdCl2 and elicited 0-85% cytotoxicity (cell attachment); 24-h incubations were used for all studies. Toxicity related inhibition of leucine incorporation into cellular protein and thymidine incorporation into DNA was noted. Decreases in protein synthesis activity closely paralleled the cytotoxicity profile; DNA synthesis was a less sensitive indicator to toxicity. K+-dependent phosphatase (KP), acid phosphatase (AP) and succinate dehydrogenase (SDH) were monitored in surviving cells and in a cell-free system. Significant inhibitions were detected for all enzyme activities following a 24 h culture with cadmium. KP and AP were most sensitive. In the cell-free system KP was significantly inhibited with 0.1 microM cadmium; AP and SDH were either unchanged or sensitive only at concentrations of 100 microM cadmium or greater. Reduced glutathione (GSH) concentration in surviving cells was elevated up to 7-fold over control cultures. The elevation occurred in a progressive toxicity-related manner.

Interactions of cis-platinum with cellular zinc and copper in rat liver and kidney tissues

In the present study the effects of cis-diamminedichloroplatinum II (cis-DDP) on tissue and subcellular concentrations of endogenous Zn and Cu was investigated in liver and kidneys of rats injected i.p. with 5 mg/kg of cis-DDP. The binding of Pt to cytosolic ligands and its effect on Zn and Cu binding was also investigated. cis-DDP significantly reduced cellular Zn (20%) and Cu (23%) levels particularly in the kidneys. Intracellularly, these decreases were largely reflected in the corresponding cytosolic fractions, with 64% decrease in Zn and 56% in Cu concentrations. At 24 h following cis-DDP injection, in both liver and kidneys, about 50% of cytosolic Pt was present as low molecular weight (LMW) species and the remainder as protein-bound. A small proportion of cellular Pt was bound to a metallothionein-like protein in the liver as well as the kidneys. The binding of renal Zn to cytosolic proteins and LMW Zn-binding ligands was significantly decreased by cis-DDP. In the liver cytosol, there was a marked redistribution of Zn and Cu from LMW Zn/Cu-binding ligand to the MT-like proteins.

Gold concentrations and toxicity during oral gold treatment with auranofin

The concentrations of gold in whole blood, serum, urine and blood cells of patients with rheumatoid arthritis were measured during 6 months of oral treatment either with Auranofin or placebo. Any adverse effects attributable to the treatments were also recorded. Although the time course of gold during Auranofin therapy was similar to that of injected gold, the blood and serum gold concentrations were significantly lower than those measured in patients receiving injected gold. Between 45 and 58% of Auranofin gold in the blood was associated with blood cells. In comparison, following injections of gold thiomalate, only about 4% of the gold was present in the blood cells. During the 6-month period, 2 patients receiving Auranofin withdrew because of diarrhoea and another because of rash. 1 placebo patient withdrew because of headaches. No laboratory evidence of haematological, renal or hepatic abnormality was encountered. It is suggested that the markedly lower concentrations of gold in the body sustained during treatment with Auranofin may be the critical factor towards a greater tolerance of the drug in the treatment of rheumatoid arthritis.

Cadmium accumulation and subcellular distribution in relation to cadmium chloride induced cytotoxicity in vitro

A bovine kidney cell culture system was used to assess what relationship cadmium (Cd) uptake and subcellular distribution had to cadmium chloride induced cytotoxicity. Twenty-four hour incubation with 0.1-10 microM Cd elicited 0-90% cytotoxicity. Fifty percent cytotoxicity was estimated to result from 0.8 microM Cd. A concentration-related Cd accumulation paralleled the cytotoxicity profile. The time-course for Cd accumulation was linear for the first 6 h of exposure and plateaued by 18 h post-exposure. When the degree of cytotoxicity was compared with the cellular Cd burden at 24 h post-treatment a least-squares linear regression analysis (r = 0.93) indicated a direct relationship. Subcellular distribution studies indicated greater than 90% Cd recovery from the soluble supernatant (105 000 g) at all levels of cytotoxicity studied. Metallothionein sequestered less than 25% of the cellular Cd. As a result of the correlation of the degree of cytotoxicity with the cellular Cd burden and the independence of subcellular distribution from cytotoxicity, a cumulative mechanism of toxicity for Cd in MDBK cells was suggested.

Comparative pharmacokinetics of trypan blue in female Sprague-Dawley and Long-Evans rats

Administration of trypan blue to pregnant Sprague-Dawley or Long-Evans rats, during an identical stage of embryogenesis, has been associated with malformations in 97 and 17% of the offspring, respectively (Gunberg, Anat. Rec. 1958, 130, 310). In the present study the comparative pharmacokinetics of trypan blue in the two strains were investigated. Female Sprague-Dawley and Long-Evans rats were injected sc with 10 mg trypan blue/rat [0.5 ml 2% (w/v) trypan blue in distilled water]. Blood samples were collected from the post-orbital plexus at times ranging from 5 min to 480 hr after dosing. The peak serum concentration of trypan blue was greater in Sprague-Dawley rats. Pharmacokinetic analyses of concentrations of trypan blue in serum resulted in fitting a two-compartment open model, with first order absorption, for both strains. Elimination of trypan blue from the central compartment was faster in Sprague-Dawley rats. This phenomenon was associated with a net movement out of the central compartment, predicted by the ratio of intercompartment rate constants. It is possible that the reported differences between the two strains in the teratogenic effects of trypan blue could be attributable, in part, to these observed pharmacokinetic dissimilarities.

Effect of repeated locoweed feeding on peripheral lymphocytic function and plasma proteins in sheep

Seven healthy, adult, crossbred yearling ewes were given (orally) 340 g of locoweed (Astragalus lentiginosus) every day for 10 weeks. Another 7 ewes were not fed the plant, but were housed similarly (controls). Blood samples were obtained once a week to evaluate the mitogen-induced lymphocytic responsiveness. For the locoweed-exposed ewes, there was decreased activity in the presence of phytohemagglutinin (a T-cell mitogen). This effect, although not statistically significant at all times, was consistent and became significant after 7 weeks. A similar response was observed in the blood cell cultures in the presence of pokeweed mitogen, but the differences were not statistically significant at most time points. For the locoweed-exposed ewes there also were gradual numerical decreases in total leukocyte and lymphocytes in peripheral blood. Peripheral leukocytes had cytoplasmic vacuolation. The results indicated that a selective effect may occur on cell-mediated immune responses. Serum proteins and gamma-globulins were not affected by locoweed treatment. Locoweed, certain species of Astragalus and Oxytropis, causes considerable economic loss to the livestock industry of western United States. Locoweed consumption by livestock can result in neurologic problems, emaciation, habituation, and reproductive alterations. The reproductive alterations include abortions, birth defects, and some interference with spermatogenesis and oogenesis. Signs of poisoning are CNS depression, rough dry coat, dull eyes, irregular gait, and excitement when stressed. The microscopic lesions are neurovisceral cytoplasmic vacuolations. Microscopic lesions are also observed in the fetuses and newborns of dams which were fed locoweed.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue distribution and pharmacokinetics of 3H-butylated hydroxyanisole in female mice

Butylated hydroxyanisole (BHA), a commonly used food additive, is a phenolic antioxidant. While metabolism of BHA has been studied in dog, man, rabbit and rat, information on tissue distribution is limited to rat and dog. Time dependent distribution and elimination of 3H-BHA following a single oral dose of 50 mg/kg body weight in female Swiss-Webster mice were investigated. Animals were sacrificed at time intervals up to 168 h after dosing. Levels of 3H were determined by liquid scintillation counting in the following tissues: brain, blood, serum, fat, heart, kidney, liver, lung, skeletal muscle and spleen. In most tissues the decline of BHA (log) was nonlinear with respect to time; a biphasic, post-absorptive aspect was observed. The highest 3H activity was noted in kidney and liver 15 min after dosing. The lowest activity was in fat. In addition, a peak 3H activity was recorded at 3 and 10 h after dosing for the blood and brain, respectively. Distribution of the 3H-BHA in mouse organs is similar to that in rat.

Cisplatinum: effect of zinc acetate pretreatment on cellular uptake and interactions with cytosolic ligands

Wistar rats were injected (i.p.) either with 5 mg cis-diamminedichloro-platinum-II (cis-DDP)/kg, or pretreated with Zn-acetate and then injected with cis-DDP. The Zn-pretreatment significantly increased the binding of Zn and Cu to both the renal and hepatic metallothioneins (MT), but the proportion of cytosolic Pt associated with MT in the kidney tissue was slightly reduced, and that in the liver showed no difference in comparison to rats treated with cis-DDP only. The results indicate that an increased MT biosynthesis by Zn-pretreatment may not correspondingly increase the binding of intracellular Pt to MT. In the Zn-acetate pretreated rats, the renal tissue and subcellular Pt levels were significantly lower (P less than 0.01) than that in untreated rats, although the liver levels showed practically no difference. It is suggested that Zn-acetate pretreatment prior to cis-DDP injection, may significantly reduce the cellular burden of Pt in the critical organ, the kidneys.

Immunotoxicologic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rabbits

Male white New Zealand rabbits were exposed orally to 0, 0.01, 0.1, 1 and 10 micrograms/kg/wk of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for a period of 8 weeks. After 4 and 6 weeks of first TCDD administration, the rabbits were inoculated with a mixture of tetanus toxoid and Freund's adjuvant. TCDD exposure reduced the serum antitoxin titers, skin sensitivity to tuberculin, and the number of antibody producing cells in popliteal lymph nodes. At the end of the treatment period serum IgG levels were increased at the lowest dose of TCDD treatment while a marked depression was noticed at the highest dose level. An increase in the thymidine uptake by splenic lymphocytes in culture was noted at all levels of TCDD treatment whereas the response of these cells to phytomitogens was decreased at high levels of TCDD exposure. All different immunologic effects were not altered at the lowest TCDD treatment but both humoral and cell-mediated immune responses were depressed at the highest level of TCDD exposure.

Triethylphosphine gold: cellular uptake and disposition after single and repeated oral doses in rats

The tissue and subcellular pharmacokinetics of gold following single and repeated oral doses of triethylphosphine gold (auranofin) has been studied in rats. After a single dose, the tissue and subcellular gold levels were 5-10 times lower than those reached with injectable gold compounds. In the liver tissues, gold concentrations peaked within 24 h followed by a biphasic clearance, with an initial rapid phase (t1/2 32 h) and a slow terminal phase (t 1/2 11 days). Renal gold concentrations continued to increase for 3 to 5 days and then decreased exponentially with a first order t 1/2 of about 7 days. Intracellularly, between 60-80% of hepatic and 50-70% of renal gold was present in the cytosol. In rats given repeated doses of auranofin, the hepatic and renal gold concentrations were 3-5 times higher than those measured after a single dose. The proportion of cellular gold present in the cytosol was markedly lower, with 43% in the liver and 30% in kidney tissues. In both the liver and kidney, gold concentrations were dose-dependent, whereas in the gastrointestinal tissues the increases as a function of dose were minimal.

Chemical interactions and compromised immune system

Only a limited number of reports are available on interactions between chemicals in relation to their effects in modifying immune functions. In many cases the exact site of chemical immunotoxicity is not well understood because immune functions are highly complex and multifaceted. Chemical interactions that have been proposed are difficult to investigate. In several cases the immunotoxicity of one chemical has been modified by a second chemical that alters xenobiotic metabolism. Immunomodulation by drugs having opposite effects on the immune system has been reported. Metals can either enhance or suppress immune responses and studies involving interactions of metals suggest both synergistic and antagonistic effects on immune responses. Various environmental chemicals that modify the immune functions may also interact with chemical carcinogens, especially since several carcinogens are also immunosuppressive.

Role of metallothionein in cellular uptake and disposition of gold sodium thiomalate

Rat liver and kidney tissue uptake of gold and its localization in the cytosol was studied following various doses of gold sodium thiomalate (GST). The timecourse of gold incorporation into intracellular gold-binding ligands following repeated injections of GST was also investigated (11 injections, one dose/week). Results show that between 30 and 60% of the hepatic and renal gold was localized in the cytosol over a wide range of GST doses. This was also true following repeated doses. In the kidney, the binding of gold to high molecular weight (HMW) proteins was saturated after the third GST dose, while incorporation into the metallothioneins (MT) continued to increase, accounting for as much as 50% of cytosolic gold. On the other hand the binding to hepatic MT was about 10x lower, and the proportion of cytosolic gold incorporated into the MT, decreased from 30% (after first 3 GST injections) to about 15% (following the last 3 injections). The results show that the stimulation of MT biosynthesis in different tissues as a response to the injected GST is not the same and varies within each organ with the dose and/or the duration of repeated exposure. In the liver, the ability of gold to induce MT synthesis was limited and the importance of MT in the cellular uptake and disposition of gold may largely be confined to the kidneys. It is suggested that besides playing a possible role in the detoxification of cellular gold, particularly in the kidney, MT may also contribute towards the retention and localization of gold in the tissues.

The halomethylketone derivative L-Glu-gamma-DL-Ala-CH2Cl and N-methyl-D-aspartate as selective antagonists against L-glutamate and kainate excitation respectively on Retzius cells of the leech, Hirudo medicinalis

Intracellular recordings were made from leech Retzius cells. The action of a range of putative antagonists was examined on the excitatory responses to dicarboxylic amino acids which were applied via a diffusion electrode. The halomethylketone derivative, L-Glu-gamma-DL-Ala-CH2Cl was found to block preferentially the L-glutamate response compared to the kainate response. This compound had no effect on the response to carbachol. N-Methyl-D-aspartate was found to block the response to kainate while having no effect on the responses to L-glutamate, ibotenate or carbachol. This compound had no direct action on the cell. N-Methyl-D-aspartic acid also reduced the excitatory responses to methyltetrahydrofolate and 3- carboxymethylpyrrolidine -2,4-dicarboxylic acid ( CMPDA ). gamma-D-Glutamyl-amino methyl-sulphonate ( GAMS ), while partially blocking the action of kainate, had no effect on the response to ibotenate. gamma-D-Glutamylglycine was found to reduce the response to L-glutamate, ibotenate, kainate, quisqualate and CMPDA . CMPDA , a tricarboxylic acid derivative of kainate, was found to be approximately equipotent with kainate on leech Retzius cells. This compound was partially blocked by N-methyl-D-aspartate. The present study demonstrates that it is possible to differentially block L-glutamate and kainate on leech Retzius cells and indicates that they are acting on separate components of the membrane.