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Experiments were carried out to examine the effects of a Fusarium contaminated wheat (10 mg deoxynivalenol and 0.76 mg zearalenone, ZON, per kg dry matter) and of a detoxifying agent (Mycofix Plus, Biomin GmbH, Herzogenburg, Austria) on the growing performance of bulls, carry-over of ZON and its metabolites into body fluids and tissues, and on nutrient digestibility in wethers. The experiments were designed according to a complete two by two factorial approach which meant that both the uncontaminated control wheat and the Fusarium toxin contaminated wheat were tested both in the absence and presence of Mycofix Plus. The growing experiment with bulls (n = 14 per treatment) covered the live weight range between 244 kg and 460 kg. The respective wheat batches were included in the concentrate portion at 65%. Concentrates were fed according to plan whereas maize silage was offered for ad libitum consumption. Daily dry matter intake and live weight gain [kg per animal and day] were 7.40, 7.52, 7.51 and 7.49 and 1.367, 1.296, 1.380 and 1.307 for bulls fed the unsupplemented control wheat, the supplemented control wheat, the unsupplemented and Fusarium toxin contaminated wheat and the supplemented Fusarium toxin contaminated wheat, respectively. ZON and its metabolites were not detected in edible tissues. The most striking effects of feeding the Fusarium toxin contaminated wheat on carcass characteristics were a reduced dressing percentage, an increased weight of the emptied gastro-intestinal tract and a reduced weight of the testicles. No effect of the detoxifying agent was seen for these parameters whereas heart weight increased independently of Fusarium toxin contamination of the concentrates. Nutrient digestibility of the two wheat batches, unsupplemented or supplemented with Mycofix Plus was evaluated according to the difference method using wethers. Presence of Fusarium toxins in wheat did not influence its feeding value. The effects of the addition of the detoxifying agent were mycotoxin unspecific and resulted in an increase in apparent digestibility of crude protein and a decrease in crude fiber digestibility. It is concluded that feeding of Fusarium toxin contaminated wheat did not adversely affect performance of growing bulls (approximately 2.2 mg DON and 0.1 mg ZON per kg complete ration at a reference dry matter content of 88%) or nutrient digestibility in wethers. The effects of the detoxifying agent Mycofix Plus on growing performance and on nutrient digestibility were rather Fusarium toxin unspecific. The slightly negative effects on growing performance needs to be examined further.

Three hundred sixty, 1-d-old male broiler chicks were fed diets containing grains naturally contaminated with Fusarium mycotoxins for 56 d. The four diets included control (0.14 mg/kg deoxynivalenol, 18 mg/ kg fusaric acid, < 0.1 mg/kg zearalenone), low level of contaminated grains (4.7 mg/kg deoxynivalenol, 20.6 mg/kg fusaric acid, 0.2 mg/kg zearalenone), and high level of contaminated grains without (8.2 mg/kg deoxynivalenol, 20.3 mg/kg fusaric acid, 0.56 mg/kg zearalenone) and with (9.7 mg/kg deoxynivalenol, 21.6 mg/kg fusaric acid, 0.8 mg/kg zearalenone) 0.2% esterified-glucomannan polymer derived from Saccharomyces cerevisiae1026 (E-GM). Body weight gain and feed consumption responded in a significant quadratic fashion to the inclusion of contaminated grains during the finisher period. Efficiency of feed utilization, however, was not affected by diets. The feeding of contaminated grains in the finisher period also caused significant linear increases in blood erythrocyte count and serum uric acid concentration and a significant linear decline in the serum lipase activity. Dietary inclusion of contaminated grains resulted in a significant quadratic effect on serum albumin and y-glutamyltransferase activity. Blood hemoglobin and biliary IgA concentrations, however, responded in significant linear and quadratic fashions. Supplementation of E-GM counteracted most of the blood parameter alterations caused by the Fusarium mycotoxin-contaminated grains and reduced breast muscle redness. It was concluded that broiler chickens may be susceptible to Fusarium mycotoxicoses when naturally contaminated grains are fed containing a combination of mycotoxins.

These studies determined (1) the time course for sphingoid base elevation in the small intestines, liver, and kidney of mice following a single 25 mg/kg body weight (bw) oral dose (high dose) of fumonisin B(1) (FB(1)), (2) the minimum threshold dose of FB(1) that would prolong the elevated sphingoid base concentration in kidney following the single high dose, and (3) the importance of the balance between the rate of sphingoid base biosynthesis and degradation in the persistence of sphingoid base accumulation. Following the high dose of FB(1), there was an increase in sphinganine in intestinal cells and liver that peaked at 4 to 12 h and declined to near the control level by 48 h. In kidney, sphinganine peaked at 6-12 h but remained elevated until 72 h, approaching control levels at 96-120 h. Oral administration of 0.03 mg FB(1)/kg bw (low dose) for 5 days had no effect on the sphingoid bases in kidney. However, following an initial high dose, daily administration of the low dose prolonged the elevation in kidney sphinganine compared to mice receiving a single high dose. Thus, a single exposure to a high dose of FB(1) followed by daily exposure at low levels will prolong the elevation of sphinganine in kidney. In cultured renal cells FB(1) was rapidly eliminated, but elevated sphinganine was persistent. This persistence in renal cells was rapidly reversed in the presence of the serine palmitoyltransferase inhibitor (ISP-1), indicating that the persistence was due to differences in the rates of sphinganine biosynthesis and degradation. The in vivo persistence in kidney may be due to similar differences.

The content of zearalenone and its metabolites in urine and tissue samples from pigs fed zearalenone-contaminated oats was established by analytical methods combining solid-phase extraction cleanup of the samples with highly selective liquid chromatography-mass spectrometry (LC-MS)/MS detection. Investigation of the urine samples revealed that approximately 60% of zearalenone was transformed in vivo to alpha-zearalenol and its epimer beta-zearalenol in a mean ratio of 3:1. Zeranol and taleranol as further metabolites could only be detected in trace amounts. Zearalanone was identified at considerable concentrations, though only in a couple of samples. In contrast, liver samples contained predominantly alpha-zearalenol, and to a minor extent beta-zearalenol and zearalenone, with a mean ratio of alpha-/beta-zearalenol of 2.5:1, while zeranol, taleranol, or zearalanone could not be identified in any of the investigated samples. The degree of glucoronidation was established for zearalenone as 27% in urine and 62% in liver; for alpha-zearalenol as 88% in urine and 77% in liver; and for beta-zearalenol as 94% in urine and 29% in liver. Analyses of muscle tissue revealed relatively high amounts of nonglucuronidated zeranol and alpha-zearalenol together with traces of taleranol and zearalenone, indicating that the metabolism of zearalenone and its metabolites is not restricted to hepatic and gastrointestinal metabolic pathways.

Secalonic acid D (SAD), a teratogenic mycotoxin, induces cleft palate (CP) in the offspring of exposed mice by inhibiting palatal shelf growth. Since reduced proliferation, increased apoptosis, and/or decreased extracellular matrix (ECM) synthesis of palatal mesenchymal cells (PMC) can all contribute to smaller shelf size, the hypothesis that teratogenically relevant concentrations (0 to 120 microg/ml) of SAD will have adverse effects on one or more of these cellular processes was tested, using primary murine PMC cultures. Exposure to SAD resulted in significant and dose-dependent decreases in mesenchymal cell number, uptake of (3)H-thymidine, and expression of proliferating cell nuclear antigen (PCNA). Trypan blue dye exclusion assay, however, revealed significant cell death only at higher doses, suggesting that the decrease in cell number at lower (more realistic) doses is likely a consequence of reduced cell proliferation and not cell death. Further, negative results in the DNA fragmentation analysis following SAD exposure suggested that cell death caused by higher levels of SAD was unrelated to apoptosis. Similarly, results of (3)H-glucosamine uptake assay indicated inhibitory effect of SAD on accumulation of hyaluronic acid (HA) or sulfated glycosaminoglycans (sGAG) only at the highest dose tested. Also, SAD affected neither extracellular nor cell-associated fibronectin expression at any dose tested. Taken together, these data suggest that the pathogenesis of CP by SAD is likely a result of a reduction in the size of the palatal shelf caused by SAD-induced inhibition of mesenchymal cell proliferation.

ICR:CD-1 male mice were orally administered with Nivalenol(NIV) at the dose levels of 5, 10 and 15 mg/kg body weight, and examined at 12, 24 and 48 hours after inoculation (HAI), respectively, to elucidate the process of development of apoptosis in the thymus, spleen and Peyer's patch. There were no signs of clinical disorders and no changes in body and organ weights until 48 HAI except for that the thymus weight significantly decreased at 48 HAI. Immunohistochemically, the number of apoptotic lymphocytes evaluated by in situ detection for fragmented DNA showed a dose-dependent increase at 12 HAI in both the thymus and the Peyer's patch, while it became to increase at 24 HAI in the spleen. Dead lymphocytes in the thymus, spleen and Peyer's patch showed ultrastructural characteristics of apoptosis. Moreover, the DNA ladder was first detected by agarose gel electrophoresis at 12 HAI in the thymus of 15 mg/kg-group. The results clearly indicate that NIV is able to induce apoptosis in the lymphoid tissues of mice.

Ochratoxin A is a typical cereal contaminant with strong nephrotoxic activity. To estimate the quantity of ochratoxin A that can be taken in by a child in the weaning period, several samples of cereal-based baby foods were analysed. Although most samples analysed contained ochratoxin A in undetectable amounts or below the Italian legal limit of 0.5 microg kg(-1), some irregular products were found. In particular, the analyses of the 119 batches (338 samples) of baby foods considered indicated that: 20 batches (16.8%) contained detectable quantities of ochratoxin A and four of these (3.4% of the total) contained ochratoxin A above the Italian permitted value. All samples coming from agricultural practices based on integrated pest management contained undetectable amounts of ochratoxin A, while approximately 5% of batches coming from conventional and organic agricultural practices were above the legal limit. On the basis of the established provisional tolerable weekly intake (PTWI), there is no significant toxicological risk for a child who occasionally consumes a formula with ochratoxin concentration slightly above the permitted level. However, stricter controls have to be applied to reject the batches containing irregular concentrations of ochratoxin A.

To explore the correlation between fumonisins and human esophageal cancer (HEC), the estimated fumonisin intake and the urinary sphinganine/sphingosine (Sa/So) ratio were investigated in the population with a high HEC incidence in the suburb of Hebi city, Henan province. Fumonisins were detected from 95 percent of corn samples in the endemic area, and the concentration of total fumonisins (fumonisin B1, B2 and B3) was in the range from 7.2 to 726.8 micrograms/kg. The estimated daily intake of fumonisins was in the range from 0 to 4.84 micrograms/(kg.d) in males, while from 0 to 4.04 micrograms/(kg.d) in females. Compared with the population in a low HEC incidence area, Suixian county, Henan province, the urinary Sa/So ratio of males in the endemic area was statistically significant higher, although no difference was observed in females. The results indicated that fumonisin might be one of the risk factors for the occurrence of HEC.

The toxicokinetics of ergovaline (an ergopeptine mycotoxin present in some grasses infected with endophytic fungus of the genus Neotyphodium) were studied after intravenous administration of a single dose of 15 microg/kg bwt in four gelding horses. Plasma ergovaline concentrations were measured by high performance liquid chromatography, and the kinetic data were described by a three-compartment model. The elimination half-life and the total clearance of ergovaline were found to be 56.83 +/- 13.48 min and 0.020 +/- 0.004 L/min x kg, respectively. According to the toxicological data previously reported in the horse, and in spite of the very low dose administered, clinical signs were observed, including excessive coolness of the ears and the nose, excessive sweating and prostration.

In this study, the possible toxic effects of Alternariol Methyl Ether (AME) and Tenuazonic Acid (TeA) produced by Alternaria species on esophagus of mice were investigated by using light and electron microscopy techniques. Mice were orally fed daily with AME or TeA for 10 months and at the end of this period, the effects of these chemicals on the esophageal mucosa were determined. By light microscopic examination, moderate and severe dysplasia characterized by loss of polarity, nuclear pleomorphism, and hyperchromasia were observed in TeA-treated animals. Electron-microscopic examination of TeA-treated mucosal epithelial cells revealed pyknosis in some nuclei, granulation and increase in chromatin mass, irregularities in the nuclear contours, vacuolization in nucleoplasms. and marked pleomorphism in the nuclei. In conclusion, our results suggested that TeA has higher toxicity as evidenced by dysplastic transformation.

Fumonisins occur widely around the world in maize products intended for human and animal consumption posing a health hazard. Direct measurement of fumonisins in physiological fluids as a biomarker of exposure is not practicable, however fumonisins disrupt sphingoid metabolism by inhibition of sphinganine N-acyltransferase. In this study the disruption in sphinganine (Sa) and sphingosine (So) levels in plasma and urine was measured in vervet monkeys (Cercopithecus aethiops) dosed with repeated gavages of 1mg fumonisin B1 (FB1)/kg body weight three times/week continuously over a 51-day period. The plasma Sa/So ratio reached a maximum (mean of 4.3) after 30 days in the dosed monkeys with a three-fold increase above the ratio of the control monkeys and then declined slowly to double the value in controls after 51 days. The lack of a clear elevation in urinary Sa/So ratios after 51 days of multiple exposure in the dosed monkeys indicates that the plasma ratio is more sensitive than urinary changes in monkeys. This is confirmed by the plasma levels of liver function enzymes of which aspartate transaminase, glutamyl-transferase and lactate dehydrogenase were increased in the dosed monkeys, while the plasma indicators of renal function were not increased above the levels in the control monkeys. Thus repeated low doses of FB1 can cause sustained disruption of sphingoid metabolism.

The effects of prenatal rubratoxin-B (RB) exposure on 8 behavioral parameters in JCL:ICR mice were assessed. Pregnant mice were injected intraperitoneally with 0.1 or 0.2 mg/kg/day of RB dissolved in propylene glycol water solution on days 7-9 (Group A) or 10-12 (Group B) of gestation. Controls received the vehicle similarly on days 7-12 of gestation. Before weaning, the offspring of both sexes were examined to test their the surface righting reflex (5 days of age), cliff avoidance response (6 days), negative geotaxis response (7 days), and swimming development (8, 10, and 12 days). After weaning, male animals were examined using the rotarod test (6 weeks of age), the open-field test (7 weeks), the shuttle-box-avoidance-learning test (9 weeks), and the water E-maze test (10 weeks). The preweanling offspring in the 0.2 mg/kg-B group showed significantly lower success rates and longer response times than controls in the cliff-avoidance response. In swimming development, the offspring in the 0.2 mg/kg B group had significantly lower scores than controls for swimming angle at 10 and 12 days of age. The avoidance learning of the mice in all RB-exposed A and B groups was significantly poorer than that of controls. These results indicate that prenatal exposure to RB produced a delay of early response development and impaired learning ability in the offspring of mice exposed to RB during middle pregnancy.

Fumonisin B1 (FB1) is a mycotoxin isolated from Fusarium fungi that contaminate crops worldwide. A previous study demonstrated that FB1 promoted preneoplastic foci in initiated rats and induced hepatocellular carcinomas in BD IX rats at 50 parts per million (ppm), but fundamental dose-response data were not available to assist in setting regulatory guidelines for this mycotoxin. To provide this information, female and male F344/N/Nctr BR rats and B6C3F1 Nctr BR mice were fed for two years a powdered NIH-31 diet containing the following concentrations of FB1: female rats, 0, 5, 15, 50, and 100 ppm; male rats, 0, 5, 15, 50, and 150 ppm; female mice, 0, 5, 15, 50, and 80 ppm; male mice, 0, 5, 15, 80, and 150 ppm. FB1 was not tumorigenic in female F344 rats with doses as high as 100 ppm. Including FB1 in the diets of male rats induced renal tubule adenomas and carcinomas in 0/48, 0/40, 9/48, and 15/48 rats at 0, 5, 15, 50, and 150 ppm, respectively. Including up to 150 ppm FB1 in the diet of male mice did not affect tumor incidence. Hepatocellular adenomas and carcinomas were induced by FB1 in the female mice, occurring in 5/47, 3/48, 1/48, 19/47, and 39/45 female mice that consumed diets containing 0, 5, 15, 50, and 80 ppm FB1, respectively. This study demonstrates that FB1 is a rodent carcinogen that induces renal tubule tumors in male F344 rats and hepatic tumors in female B6C3F1 mice.

The carcinogenicity of fumonisin B1 (FB1), a worldwide contaminant of corn produced by Fusaria species of fungi, has been tested recently in 2-year feeding studies in Fischer F344 rats and B6C3F1 mice. Inclusion of FB1 at 50 and 80 ppm in the diet induced liver tumors in female mice, and at 50 and 150 ppm induced renal tumors in male rats (22). In the present study, the kidneys from the rat bioassay were examined to characterize the various histopathological changes associated with renal tumor induction. In all high-dose (150 ppm) and mid-dose (50 ppm) male rats, and to a lesser extent in high-dose (100 ppm) female rats, there was evidence of sustained nephrotoxicity manifested as basophilia, apoptosis, cell regeneration, and simple tubule hyperplasia, affecting proximal convoluted tubules in the deep cortex, extending into the outer region of the outer stripe of outer medulla. A further alteration consisted of sporadic areas of interstitial hyalinization in deep cortex, suggestive of expanded basement membrane, coupled with tubule atrophy. The continued presence of nephrotoxicity throughout chronic exposure to FB1 suggested that renal tumor development may have been an outcome of sustained cell loss and compensatory regeneration. In some cases, preneoplastic tubules or incipient renal tumors presented an immature or fetal form in association with interstitial hyalinization. The renal tubule tumors induced by FB1 were typified by a rare, highly malignant, anaplastic variant capable of growth by infiltration. Of the 10 renal tubule tumors diagnosed in the mid-dose males, and the 16 in the high-dose males, 8 and 10, respectively, were graded as carcinomas. Anaplastic variants represented 50% of the mid-dose carcinomas and 80% of the high-dose carcinomas. One of the anaplastic carcinomas in a mid-dose male was a true sarcomatoid phenotype not previously recorded in the rodent. Metastatic invasion of the lung occurred with 25% of the mid-dose carcinomas and 50% of the high-dose carcinomas. It was speculated that FB1 may have been influencing the growth characteristics of the induced renal tumors via its inhibitory action on the synthesis of sphingolipids, which in turn, participate in regulating cell contact, growth, and differentiation, or alternatively by affecting cell adhesion molecules.

Fumonisin B(1) is the most toxic and commonly occurring form of a group of mycotoxins that alter sphingolipid biosynthesis and induce leukoencephalomalacia in horses and pulmonary edema in pigs. Purified fumonisin B(1) (1 mg/kg, iv, daily) increased serum sphinganine and sphingosine concentrations and decreased cardiovascular function in pigs within 5 days. We therefore examined whether the same dosage schedule of fumonisin B(1) produced a similar effect in calves. Ten milk-fed male Holstein calves were instrumented to obtain blood and cardiovascular measurements. Treated calves (n = 5) were administered purified fumonisin B(1) at 1 mg/kg, iv, daily for 7 days and controls (n = 5) were administered 10 ml 0.9% NaCl, iv, daily. Each calf was euthanized on day 7. In treated calves, serum sphinganine concentration increased from day 3 onward (day 7, 0.237 +/- 0.388 micromol/l; baseline, 0.010 +/- 0.007 micromol/l; mean +/- SD), whereas, serum sphingosine concentration was unchanged (day 7, 0.044 +/- 0.065 micromol/l; baseline, 0.021 +/- 0.025 micromol/l). Heart rate, cardiac output, stroke volume, mean arterial pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, central venous pressure, plasma volume, base-apex electrocardiogram, arterial Po(2), and systemic oxygen delivery were unchanged in treated and control calves. Fumonisin-treated calves developed metabolic acidosis (arterial blood pH, 7.27 +/- 0.11; base excess, -9.1 +/- 7.6 mEq/l), but all survived for 7 days. We conclude that calves are more resistant to fumonisin B(1) cardiovascular toxicity than pigs.

Fumonisins are a group of mycotoxins that alter sphingolipid biosynthesis and induce leukoencephalomalacia in horses and pulmonary edema in pigs. Experimental administration of fumonisin induces hepatotoxicity in all species, including cattle, as well as nephrotoxicity in rats, rabbits, and sheep. We investigated the hepatotoxicity and nephrotoxicity of fumonisin B(1) to calves. Ten milk-fed male Holstein calves aged 7 to 14 days were instrumented to obtain blood and urine. Treated calves (n = 5) were administered fumonisin B(1) at 1 mg/kg, iv, daily and controls (n = 5) 10 ml 0.9% NaCl, iv, daily until euthanized on day 7. Fumonisin B(1)-treated calves were lethargic and had decreased appetite from day 4 onward, serum biochemical evidence of severe liver and bile duct injury, and impaired hepatic function. Treated calves also had biochemical evidence of renal injury that functionally involved the proximal convoluted tubules. Sphinganine and sphingosine concentrations in liver, kidney, lung, heart, and skeletal muscle were increased in treated calves. Sphinganine, but not sphingosine, concentration was increased in brains of treated calves. In fumonisin B(1)-treated calves, hepatic lesions were characterized by disorganized hepatic cords, varying severity of hepatocyte apoptosis, hepatocyte proliferation, and proliferation of bile ductular cells. Renal lesions in treated calves consisted of vacuolar change, apoptosis, karyomegaly, and proliferation of proximal renal tubular cells, as well as dilation of proximal renal tubules, which contained cellular debris and protein. This is the first report of fumonisin B(1)-induced renal injury and organ sphingolipid alterations in cattle.

Experts from the Nordic countries (Denmark, Norway, Sweden, Finland and Iceland) have carried out an evaluation of fumonisins. The working group members concluded that, at that time point, it was not possible to carry out a complete risk assessment. However, it was recommended that the human daily' intake of fumonisins should be less than 1 microg/kg bw/day. Subsequently, the presence of the Fusarium mycotoxins fumonisin B1 and B2 (FB1 and FB2) in corn-based food on the Danish retail market has been determined. A total of 70 samples were analysed and 37% contained FB1 and 21% contained FB2. No fumonisins were found in sweet corn (canned or frozen), corn-on-the-cob, corn starch or gruel powder for babies. FB1 was found in about half of the corn flakes, corn snack and popcorn (not popped) samples, whereas FB2 was seen to a lesser extent. Both FB1 and FB2 were found in 75% or more of the corn flour, tacos and polenta samples. In general, the content of FB1 was in the range of 1-1000 micro/kg and the content of FB2 was in the range of 4-250 microg/kg. Corn-based foods are consumed in rather low amounts and irregularly among the Danish population and therefore it is not meaningful to calculate an average daily funonisin intake. An estimate for an 'eater' shows that the intake of fumonisins will not exceed 0.4 microg/kg bw/day.

Fumonisin B1 (FB1) is an inhibitor of sphinganine N-acyltransferase and the increase in the sphinganine/ sphingosine (Sa/So) ratio in urine or serum has been proposed as a biomarker to evaluate exposure to fumonisins. The objectives of this study were to (1) develop a liquid chromatographic method sufficiently sensitive to determine the low concentration of free Sa in male human urine, and (2) analyse So and Sa in human urine and monitor the Sa/So ratio in urine of humans exposed to FB1 in corn diets over 1 month. The liquid chromatographic method involved isolation from human urine of exfoliated cells followed by an extraction of free sphingoid bases and their separation and quantification by high performance liquid chromatography. The detection limits for So and Sa were 0.15 ng/ml in female urine (2 ml used) and 0.005 ng/ ml in male urine (60 ml used). Twenty-eight healthy adult volunteers consumed for 1 month a normal diet containing their homegrown corn potentially contaminated with FB1. Immediately preceding the start of the test, morning urine samples for the determination of So and Sa were collected from each person, and the corn samples used in cooking were obtained from each family for the determination of FB1. At the end of the test period, morning-urine samples were collected from each person and analysed again. The daily FB1 intakes were estimated and used to assess the relationship between them and the urinary Sa/So ratios in humans exposed to dietary FB1 over 1 month. All the homegrown corn samples contained FB1 ranging from 0.08 to 41.1 mg/kg, and the estimated daily FB1 intakes ranged from 0.4 to 740 microg/kg b.w./day. The 1-month monitoring results suggest that sphingolipid metabolism of humans could be affected by FB1 intake, the urinary Sa/So ratio may be useful for evaluating FB1 exposure when the contamination of FB1 is high, and that males are more sensitive to FB1 disruption of sphingolipid metabolism than females.

Quantitative risk analysis permits modifying risk estimates with changes in variables such as exposure. This analysis for exposure to the mycotoxin fumonism describes the magnitude of adverse effects, variability in the population and uncertainty of models as a range of possible outcomes. The most sensitive adverse response in rats, nephrotoxic lesions, was used for the dose-response analysis. Dietary intake of corn products was estimated from a 3-day consumption survey. Levels of corn in each product were estimated by standard methods. Fumonisin levels in corn products were estimated from Food and Drug Administration (FDA) surveillance data and distributions of fumonisin consumption were modelled for each eater in the survey population. Uncertainty for predictions made from each model and uncertainty resulting from model selection were described. Results of the dose-response and exposure analyses were assimilated in a two-dimensional Monte-Carlo simulation. Distributions representing variability and uncertainty were iteratively selected to form an array of estimates of the risk. On the basis of this analysis, current dietary levels of fumonisin would not result in renal lesions even at upper levels of exposure. To avoid toxicity at much higher doses, limiting corn intake would be more effective than would limiting the level of fumonisin in corn.

The gram-positive bacterium Streptococcus gordonii was engineered to express the microbicidal molecule H6, which is an antiidiotypic single chain antibody mimicking a yeast killer toxin. S. gordonii is a human commensal which we developed as a model system for mucosal delivery of heterologous proteins. The in vivo candidacidal activity of both H6-secreting and H6-surface-displaying streptococcal strains were assayed in a well-established rat model of vaginal candidiasis. At day 21 full clearance of Candida albicans infection was observed in 75% of animals treated with the H6-secreting strain, and in 37.5% of animals treated with the strain expressing H6 on the surface, while all animals treated with the control strain were still infected. The observed candidacidal effect was comparable with that observed with the antimycotic drug fluconazole. These data confirm the potential of H6 as a candidacidal agent and show how promising is the approach of using recombinant bacteria for mucosal delivery of biologically active molecules.

Two recombinant strains of Streptococcus gordonii, secreting or displaying a microbicidal single-chain antibody (H6), and stably colonizing rat vagina, were used to treat an experimental vaginitis caused by Candida albicans. A post-challenge intravaginal delivery of the H6-secreting strain was as efficacious as fluconazole in rapidly abating the fungal burden. Three weeks after challenge, 75% and 37.5% of the rats treated with the H6-secreting or displaying bacteria, respectively, were cured of the infection, which persisted in 100% of the animals treated with a S. gordonii strain expressing an irrelevant single-chain antibody. Thus, a human commensal bacterium can be suitably engineered to locally release a therapeutic antibody fragment.

Fumonisins B1 and B2 (FB1 and FB2) are fungal secondary metabolites produced by members of the genus Fusarium. Although FB1 is usually detected in greater quantities, FB2 frequently co-occurs in contaminated feeds and foods and contributes to the total toxin load. In the present study, the comparative toxicity of FB1 and FB2 was examined in male Sprague-Dawley rats administered toxin (0.75 mg/kg body weight) or vehicle control intraperitoneally (ip) for 2, 4 or 6 consecutive days. Clinical changes, including elevated serum cholesterol, alanine aminotransferase (ALT), creatinine and protein, were slightly more pronounced in FB1-treated rats. The most consistent hematological change was an increase in vacuolated bone marrow cells, which was more pronounced in FB1-treated rats. Histopathological changes were similar in FB1- and FB2-treated rats and included single cell necrosis in kidneys and liver, cytoplasmic vacuolation in adrenal cortex and lymphocytolysis in thymus. In the liver mRNA expression for the cyclin kinase inhibitor p21 gene was significantly increased in FB1- and FB2-treated rats, compared to controls. Expression of mRNA for the cyclin D1 gene was significantly depressed in FB2-treated rats. Hepatic cyclin E mRNA was elevated in response to FB1 and FB2 compared to controls. In FB2-treated animals this corresponded with decreased liver p27 mRNA expression. Hepatic proliferating cell nuclear antigen (PCNA) transcription was elevated in FB1- but not FB2- treated rats. Changes in liver microsomal protein levels of p27, cyclin E and PCNA were similar to changes in gene expression. In contrast, cyclin D1 protein levels were elevated in rats treated with FB1 and, to a lesser extent, FB2. The data indicate that FB1 and FB2 can alter the expression of genes associated with the cell cycle, and indicate a need for a further understanding of the mechanistic basis of FB1 and FB2 toxicity.

Fumonisin B(1) is a fungal inhibitor of ceramide synthase, a key enzyme in the de novo biosynthesis of sphingolipids. The resulting increase in tissue free sphinganine (and sometimes sphingosine) is used as a biomarker for fumonisin exposure. This study determined whether a single subcutaneous injection of fumonisin B(1) could cause an increase in free sphingoid bases in the intestinal epithelial cells of mice over 24 hr. It was hypothesized that fumonisin administered subcutaneously would be excreted into the small intestine via biliary excretion, and this should be detectable by increased sphingoid bases in the intestine. A significant time-dependent increase in sphingoid bases occurred in the intestine and liver peaking at 4-8 hr and declining to control levels by 24 hr. In the kidney the increase in free sphinganine was persistent. The parallel time course of the change in sphinganine in the intestine and liver suggested fumonisin B(1) was rapidly excreted into the small intestine. Rapid cell turnover in the intestine could account for the reversal of the sphinganine increase. The rapid return to the control level in liver was unexpected since ceramide synthase inhibition in cultured cells is persistent suggesting that liver handles fumonisin B(1) or sphingoid bases quite differently than kidney.

Fumonisin mycotoxins are common contaminants of maize and cause several fatal animal diseases. Liver is a target organ of fumonisins in intact animals, but liver slices and primary hepatocytes, which do not proliferate in culture, are resistant to fumonisin exposure. Hepatoma cell lines, on the other hand, undergo cell division in culture and are sensitive to the toxic effects of fumonisins. It was therefore hypothesized that fumonisin cytotoxicity is dependent on cell proliferation. To test this hypothesis, the partially hepatectomized rat was used as a model to determine whether fumonisin produced greater toxicity in rapidly proliferating liver in vivo. Rats were dosed intraperitoneally with fumonisin B1 (FB1) 24 h after sham operation or partial hepatectomy (PH) and were killed 24 h later. The dose-related increase in free sphingoid bases (a biomarker of fumonisin exposure) was enhanced in the PH-treated rats. Serum cholesterol and enzymes were higher in PH-treated rats dosed with FB1 than in those given PH without FB1 or in sham-operated, FB1-dosed rats. Multiple daily doses of FB1 after surgery elevated the number of apoptotic hepatocytes in both sham-operated and PH-treated rats to about the same degree, suggesting that apoptosis is not associated with the enhanced cytotoxicity of FB1 in regenerating liver. Proliferating cells appear to be more sensitive to the toxic effects of fumonisins. This enhanced cytotoxicity may be related to the increased ability of fumonisins to disrupt sphingolipid metabolism in hepatectomized rats, but this is yet to be determined.

The sensitivity of elevated serum ornithine carbamyltransferase (OCT) as an index of hepatotoxicity in rats was assessed in different studies conducted over a number of years and originally designed to examine the toxicity or carcinogenicity of a variety of test chemicals and diets. Changes in serum OCT activities were compared with the more widely used clinical endpoints, alanine aminotranserase (ALT) and aspartate aminotransferase (AST). In the first study, rats received a single oral dose of the hepatotoxic and hepatocarcinogenic fungal toxin aflatoxin B(1) (AFB(1)). The increase in enzyme levels between control and AFB(1)-treated rats was greater for serum OCT than for ALT or AST. This response was similar to the changes in serum enzyme levels in studies where rats ingested a hepatotoxic and hepatocarcinogenic choline deficient (CD) diet. When rats were exposed to the hepatotoxic and nephrotoxic fungal toxin fumonisin B(1) (FB(1)) by intraperitoneal injection for 6 days, serum AST and ALT were significantly elevated above control levels while OCT was unaffected. The peroxisome proliferator ciprofibrate caused elevated ALT and AST but not OCT at week 52 of dietary exposure, after the development of liver nodules and tumours. Of the two liver-specific enzymes examined in all of the studies, ALT was more consistently predictive of hepatotoxicity than OCT.

The kinetics of fumonisin B1 (FB1) after single doses of 10 mg FB1/kg (po) or 2 mg FB1/kg (i.v.) were studied in male Wistar rats. Serial blood samples were obtained after p.o and i.v. administration. Liver and kidney tissue samples were also obtained after p.o administration. Plasma, liver and kidney concentrations of FB1 were determined by a reversed-phase high-performance liquid chromatographic assay using precolumn 0-phthaldialdehyde derivatisation with fluorescence detection. The FB1 plasma profile could be adequately described by a 2-compartment open model. For FB1, the elimination half-life from plasma was 1.03 h after i.v. and 3.15 h after p.o administration. The apparent volume of distribution and volume of distribution at steady state for FB1 were 0.11 and 0.072 L, respectively, after i.v. administration. The total plasma clearance of FB1 was the same for both the p.o and i.v. routes, 0.072 L/h. After the single p.o dose, FB1 was rapidly absorbed with a Tmax of 1.02 h. The maximum plasma concentration of FB1 was 0.18 microgram/mL. The p.o bioavailability of FB1 was 3.5%. The tissue concentration time data for FB1 fit a 1-compartment open model. Considerable concentrations of FB1 were found in the liver and kidney tissues. The elimination half-lives for FB1 were longer for liver (4.07 h) and kidney (7.07 h) than for plasma (3.15 h). Tissue accumulation of FB1 was evidenced by the tissue/plasma area under the concentration-time curve (AUC) ratios; the AUCtissue/AUCplasma for FB1 was 2.03 in liver and 29.89 in kidney.

Beginning at 24 wk of age, control diets or diets containing 50 or 100 mg/kg moniliformin (M), 100 or 200 mg/kg fumonisin B1 (FB1), or a combination of 50 mg M and 100 mg FB1/kg of diet were fed to White Leghorn laying hens for 420 d. The hens were then fed the control diet for an additional 60 d. At the beginning of the experiment, each treatment consisted of four replicates of six hens. Egg production was reduced by approximately 50% by the end of the second 28-d laying period and remained at approximately this level for the 420 d in only the hens fed the diet containing 100 mg M/kg feed. Production returned to control levels or above within 60 d after hens were fed the control diet. Egg weights were reduced by the 100-mg M diet during the first three 28-d laying periods before returning to weights comparable with controls. The hens in this group also had significantly lower body weights than the other treatments. Mortality was minimal except in hens fed the 100 mg M/kg diet and the 100 mg FB1/kg diet, on which approximately 20% of the hens died. The hens were artificially inseminated with semen from males fed control diets, and fertility was not affected by the dietary treatments. Importantly, toxic synergy between M and FB1 was not observed for any of the parameters measured. Results indicate that laying hens may be able to tolerate relatively high concentrations of M and FB1 for long periods of time without adversely affecting health and performance. Interestingly, hens fed the 100-mg M/kg diet were able to recover when returned to control diets. The likelihood of encountering M or FB1 at these concentrations in finished feed is small.

The effects of feeding diets containing either 20 mg deoxynivalenol (DON)/kg, 100 mg moniliformin (M)/kg, or a combination of DON and M (20 mg/kg DON and 100 mg M/kg) were evaluated in growing turkey poults, from 1 to 21 d of age. Feed intake and BW gains were decreased (P < 0.05) by dietary treatments containing M. Feed conversion was not affected by any of the dietary treatments, and no interactive effects on performance were evident between M and DON. Absolute weights of hearts and kidneys were increased (P < 0.05) in poults fed diets containing M. Mean cell volume was decreased by the M and DON-M treatments; however, the decrease was much smaller in poults fed the combination DON-M treatment resulting in a significant (P < 0.05) DON by M interaction. Mean cell hemoglobin and mean cell hemoglobin concentrations were not affected by any of the dietary treatments. No histological lesions were seen in control poults or poults fed DON alone. Lesions associated with dietary treatments were only observed in the heart and kidney. Poults fed diets containing M alone or the DON-M combination exhibited an increased incidence of variable sized cardiomyocyte nuclei, with numerous large giant nuclei, and a generalized loss of cardiomyocyte cross striations. Isolated renal tubules in sections of kidney were noted to have mild diffuse mineralization in poults fed M and the combination DON-M treatments. None of the response variables measured were affected by DON alone. No toxic synergy was observed when these toxins were fed simultaneously to turkey poults for 21 d.

Fumonisins and fusaric acid (FA) are mycotoxins produced by Fusarium moniliforme and other Fusarium which grow on corn. Fumonisins cause animal toxicities associated with F. moniliforme and, like F. monliforme, they are suspected human oesophageal carcinogens. Toxic synergism was obtained by simultaneous administration of FA and fumonisin B1 to chicks in ovo. To determine the effect of FA on in vivo toxicity of F. moniliforme culture material (CM), male rats (12 groups, n = 5/ group) were fed diets containing 0.025, 0.10 or 2.5% CM (providing dietary levels of 3.4, 18.4 or 437 ppm fumonisins, respectively) to which, at each CM level, 0, 20, 100 or 400 ppm FA were added. Additionally, an FA control group was fed 400 ppm FA only and an untreated control group was given neither FA nor culture material. Apoptosis and other effects consistent with those caused by fumonisins were present in the kidneys of animals fed 0.025% or more CM and in the livers of animals fed 2.5% CM. FA was without effect. No differences between the untreated and FA control groups were noted and no differences among the four groups (0-400 ppm FA) fed 0.025% CM, the four groups fed 0.10% CM or the four groups fed 2.5% CM were apparent. Thus, FA exerted no synergistic, additive or antagonistic effects on the subchronic in vivo toxicity of fumonisin-producing F. moniliforme.

Fumonisin B1 (FB1) is a carcinogenic mycotoxin produced by the fungus Fusarium moniliforme in corn. Feeding of FB1 to rats causes acute liver injury, chronic liver injury progressing to cirrhosis, and sometimes terminates in hepatocellular carcinoma or cholangiocarcinoma. This study describes the histolopathology and changes in gene expression in the rat liver during short-term feeding of FB1. Male Fischer rats were fed either FB1 250 mg/kg or control diet, and were killed weekly for 5 weeks. FB1 caused a predominantly zone 3 'toxic' liver injury, with hepatocyte death due to necrosis and apoptosis. Hepatocyte injury and death were mirrored by hepatic stellate cell proliferation and marked fibrosis, with progressive disturbance of architecture and formation of regenerative nodules. Despite ongoing hepatocyte mitotic activity, oval cell proliferation was noted from week 2, glutathione S-transferase pi-positive hepatic foci and nodules developed and, at later time points, oval cells were noted inside some of the 'atypical' nodules. Northern blot (mRNA) analysis of liver specimens from weeks 3 to 5 showed a progressive increase in gene expression for alpha-fetoprotein, hepatocyte growth factor, transforming growth factor alpha (TGF-alpha) and especially TGF-beta1 and c-myc. Immunostaining with LC(1-30) antibody demonstrated a progressive increase in expression of mature TGF-beta1 protein by hepatocytes over the 5 week feeding period. The overexpression of TGF-beta1 may be causally related to the prominent apoptosis and fibrosis seen with FB1-induced liver injury. Increased expression of c-myc may be involved in the cancer promoting effects of FB1.

Hydrolysis of the mycotoxin ochratoxin A (OA) to ochratoxin alpha (Oalpha) by microorganisms within the gastrointestinal tract leads to the excretion of OA as the nontoxic alpha form. The Oalpha form is the principal means for the detoxification of OA. In the current experiment, three groups of four sheep were fed diets consisting of 70% concentrates and 30% hay (dry matter basis, energy to supply 1.1 times the requirement for maintenance) for 4 wk with three dietary concentrations of OA (0, 2, or 5 mg/kg of concentrate feed). The OA content did not affect feed intake or nutrient digestibility. In a preliminary experiment, an OA dose of 20 mg/kg of concentrate feed greatly reduced feed intake. After 1, 2, 3, and 4 wk of the trial, significant concentrations of OA were detected in the serum of the animals fed 2 or 5 mg of OA/kg feed. This suggested that even at a dosage of 2 mg of OA/kg of concentrate feed, considerable amounts of OA were not degraded by ruminal and intestinal microorganisms. The analysis of the feces and urine samples reflected these findings; OA and Oalpha were found in significant concentrations, escaping fermentation in the rumen and in the hindgut. The current experiment demonstrates that OA hydrolysis in the gastrointestinal tract of sheep is substantially less than previously described, especially if OA is ingested in combination with concentrate-rich diets.

In weaners, combined administration of fumonisin, deoxynivalenol and T2 together with ochratoxin A in quantities expected to be present in feeds of central European origin resulted, as a rule, in changes identical to those observed after single administration of ochratoxin A. Such reactions were partly compensated. Synergistic amplification of immunosuppressive changes due to the simultaneous intake of these mycotoxins in low concentrations is not to be expected.

Even in subtoxic amounts, the mycotoxin, ochratoxin A, produced immunomodulation in weaner pigs in a dose-dependent mode. In addition to increased counts of total leukocytes and neutrophils in the blood, reduced lymphocyte levels were observed. There was a striking increase in the counts of eosinophils and of apoptotic phagocytes. Functionally, there was a predominance of the production of reactive oxygen radicals in whole blood, reduced phagocytosis performance and reduced expression of a swine-specific surface marker (SWC1) on lymphocytes. In a few single experiments, clinical manifestations could be demonstrated. Lung clearance and the degree of severity of experimental pneumonia as well as cutaneous hypersensitization may be influenced by ochratoxin A.

Changes in the activity of enzymes involved in oxidative metabolism of glutamine, and in protein content, in the epithelial tissue along the gastrointestinal (GI) tract of growing pigs exposed to nivalenol (NIV) in the diet were investigated. The epithelial tissue was taken from the stomach, small intestine and colon of three groups of animals fed diets without NIV (control), with inclusion of 2.5 mg NIV/kg diet (low dose) and with inclusion of 5.0 mg NIV/kg diet (high dose). The activities of glutaminase, glutamate dehydrogenase, oxoglutarate dehydrogenase, isocitrate dehydrogenase and alanine aminotransferase were determined. In the control pigs the activities of oxoglutarate dehydrogenase and alanine aminotransferase were higher (P < 0.05) in the epithelium of the small intestine as compared with the stomach and colon, while there were no differences in the activities of glutaminase, glutamate dehydrogenase and isocitrate dehydrogenase. With increasing inclusion of NIV in the diet the activity of oxoglutarate dehydrogenase decreased (P < 0.05) in the epithelium of the small intestine and colon, and the activity of alanine aminotransferase tended (P = 0.07) to increase in the epithelium of the small intestine. The activities of glutaminase, glutamate dehydrogenase and isocitrate dehydrogenase remained unaffected by the inclusion of NIV in the diet. In the control pigs the protein content in the epithelium of the small intestine was higher (P < 0.05) than in the stomach and colon, while there were no effects of NIV inclusion in the diet on the protein content. It can be concluded from the present study that the epithelial tissue of the small intestine and colon of pigs exposed to a diet containing NIV will have a reduced enzymatic capacity to utilise alpha-ketoglutarate in the tricarboxylic acid cycle (TCA-cycle), suggesting an impaired energy supply to these organs.

Malignant hyperthermia (MH) and the mycotoxin cyclopiazonic acid (CPA) are each associated with abnormal calcium homeostasis in skeletal muscle, a key underlying factor in the development of pale, soft, and exudative (PSE) pork. To determine whether the natural presence of CPA in livestock feed ingredients contributes to the varying incidence of PSE in the pork industry, various levels of CPA (.1 to 50 mg/kg of diet) were included in the diets of market weight hogs (n = 52) of defined malignant hyperthermia genotype (NN = normal, Nn = a MH carrier, and nn = MH-positive). Animals with two copies of the MH mutation (nn) displayed improved live animal performance compared with NN and Nn animals (increased feed intake, average daily gain, and feed efficiency) but yielded lower quality loin chops as indicated by lower 45-min pH (P<.01), higher Commission Internationale de l'Eclairage (CIE) L* color coordinate values (P<.05), and higher drip losses (P<.01). The effects of CPA varied. In the first feeding trial, conducted under normal outside temperatures (2 degrees C), CPA had no effect (P> .2) on either live animal performance or meat quality. During the second trial, conducted under extreme outside temperatures (-18 degrees C), CPA-dependent reductions (P<.05) in feed intake, average daily gain, and 45-min pH in nn hogs support the possibility of interactions between malignant hyperthermia and dietary CPA on skeletal muscle calcium homeostasis and the development of PSE pork. These results suggest that this interaction may require stressful environmental conditions or the ingestion of CPA doses much higher than occur under natural conditions.

Fumonisin B1 (FB1), a mycotoxin produced by a common corn contaminant Fusarium moniliforme and a hepatocarcinogen in rats, has been previously suggested to act as a poor initiator, but a better promoter of gamma-glutamyltranspeptidase (GGT)-positive rat liver preneoplastic lesions. Using glutathione S-transferase-placental form (GSTP) as a more sensitive marker of initiation, we have further evaluated the initiating capacity of various doses of purified FB1 administered (a) intraperitoneally (i.p.) to male Sprague-Dawley (SD) rats for 4 days and (b) orally (PO) to male and female SD rats for 11 days. Compared to their respective controls, significant increases in GSTP-positive hepatocytes were observed in male rats administered FB1 i.p. at 10 mg/kg body weight/day for 4 days, as well as in male and female rats treated with 35 and 75 mg/kg body weight/day FB1 p.o. for 11 days. The percentage section area of liver occupied by GSTP-positive mini-foci comprising of three to 12 cells was increased significantly in male rats given 10 mg/kg FB1 i.p., or in p.o.-treated males and females with 75 mg/kg FB1. Both i.p. and p.o. FB1 treatments resulted in dose-related enhanced hepatocyte proliferation as measured by proliferating cell nuclear antigen (PCNA) labeling with significant increases in the number of PCNA-positive nuclei at the same i.p. and p.o. dose levels where the number of GSTP-positive cells were elevated. In all studies, enhanced PCNA and GSTP expression occurred at FB1 doses which, based on serum biochemical and histopathological data previously reported from our laboratory, were shown to be hepatotoxic. Therefore, our data suggest that in a manner similar to known genotoxic carcinogens, FB1 has the capacity to initiate GSTP-positive hepatocytes with their subsequent development into GSTP mini-foci at exposure levels that induce enhanced hepatocyte proliferation in response to liver toxicity. In SD rats, this occurs as early as within 4 days of i.p. treatment or 11 days of p.o. treatment.

The effects of fusarenon-X (12,13-epoxytrichothecene; FX) on mouse thymus and T-cell subpopulations were studied. In mice that received three intraperitoneal injections of FX, the thymus showed severe atrophy, the thymic cortex almost completely disappeared, and the total number of thymocytes decreased to 2.2% of that of normal mice. CD4+ CD8+ thymocytes were almost completely depleted by this treatment while CD4+ CD8-, CD4- CD8+ and CD4- CD8- thymocytes were not reduced to such an extent, suggesting that selective damage in CD4+ CD8+ thymocytes was induced by FX. In spleen, CD4+ or CD8+ lymphocytes and CD4- CD8- non-T cells remained unchanged. Next, the mode of damage in thymocytes was investigated by a single injection with FX. The lymphocyte nuclei were fragmented and positive for TUNEL (TdT-mediated dUTP nick-end labeling) staining in the thymic cortex 20 h after FX injection. By electron microscopy, apoptotic lymphocytes with condensed nuclei and stroma cells ingesting many nuclear fragments were frequently observed in the thymic cortex. Internucleosomal DNA fragmentation was apparent in the thymocytes treated with FX both in vivo and in vitro. Thus, we demonstrated that the trichothecene mycotoxin FX is a new cause of apoptosis in CD4+ CD8+ thymocytes of mice besides the other factors that cause similar effects.

Fumonisin B1, a mycotoxin produced by Fusarium moniliforme, inhibits the activity of ceramide synthetase, the key enzyme in sphingolipid biosynthesis, leading to accumulation ofsphinganine and sphingosine. Ceramide and other sphingolipid pathways have been implicated in signal-induced apoptosis in cells. Groups of male BALB/c mice received subcutaneous injections (0, 0.25, 0.75, 2.25 or 6.25 mg/kg) of fumonisin B1 daily for 5 days and the liver and kidneys were sampled 1 day after the last injection. A decrease in kidney weight was observed after fumonisin treatment. A "blind" random evaluation of stained sections revealed dose-dependent fumonisin B1-associated hepatic and renal lesions in all groups. Terminal uridine triphosphate (UTP) nick-end labelling (TUNEL) in liver and kidney sections confirmed the presence of dose-related apoptotic cells at all treatment levels. Thus fumonisin B1 produced apoptosis after a brief exposure to relatively low doses. The toxicity of fumonisin B1 was greater than that previously found in studies on oral toxicity.

Objective: To characterize clinical features, diagnostic evaluation, and treatment outcome for dogs with generalized tremors., Design: Retrospective case series., Animals: 12 white purebred and 12 nonwhite mixed-breed and purebred dogs., Procedure: Medical records of dogs examined for tremors between January 1984 and July 1995 were reviewed. History, signalment, abnormalities on physical and neurologic examinations, results of diagnostic testing, and diagnosis were recorded for each dog. Results were divided into the following 3 categories on the basis of the cause of the tremors: inflammatory, noninflammatory, and idiopathic. Cause was determined by results of CSF analyses or a history of toxin exposure., Results: The only noninflammatory cause of generalized tremors identified in these dogs was mycotoxin ingestion. Steroid-responsive tremor syndrome had developed in 22 of 24 dogs, half of which had abnormal results of CSF analyses. Most dogs were young adults between 1 and 5 years old. More than half of the dogs were nonwhite mixed-breeds and all weighed < 15 kg (33 lb). Eighty percent of the dogs responded to immunosuppressive treatment within 3 days., Clinical Implications: Inflammatory and noninflammatory causes for generalized tremors in dogs result in similar clinical signs, so a logical diagnostic and treatment approach is needed. Steroid-responsive tremor syndrome should be considered in small- to medium-breed, young adult dogs, regardless of coat color. A rapid and complete response to immunosuppressive treatment is expected.

The effect of Indian herbs namely, Asparagus racemosus, Tinospora cordifolia, Withania somnifera and Picrorhiza kurrooa on the functions of macrophages obtained from mice treated with the carcinogen ochratoxin A (OTA) was investigated. The chemotactic activity of murine macrophages was significantly decreased by 17 weeks of treatment with OTA compared with controls. Production of interleukin-1 (IL-1) and tumor necrosis factor (TNF) was also markedly reduced. Treatment with Asparagus racemosus, Tinospora cordifolia, Withania somnifera and Picrorhiza kurrooa significantly inhibited OTA-induced suppression of chemotactic activity and production of IL-1 and TNF-alpha by macropahges. Moreover, we found that Withania somnifera treated macrophage chemotaxis and that Asparagus racemosus induced excess production of TNF-alpha when compared with controls.

Ochratoxin A (OA) is a mycotoxin that is produced on moist grain. It is commonly found in the blood of swine in western Canada and is a potent nephrotoxic, carcinogen, and immunosuppressive agent. The pharmacokinetic characteristics of six analogs of OA including OA, OB (OA without chloride), OC (OA ethyl ester), and some metabolites, such as O alpha (OA without phenylalanine), OA-OH (hydroxylated OA), and a newly discovered form of OA, OP-OA (lactone opened ring of OA), were investigated in rats after a single intravenous administration of the compounds. All of the ochratoxin analogs were distributed following a two compartment open model. The elimination half-lives of OA, OP-OA, O alpha, OA-OH, OB, and OC were 103+/-16, 50.5+/-2.8, 9.6+/-2.3, 6+/-0.9, 4.2+/-1.2, and 0.6+/-0.2 hr, respectively. Total body clearance of OA, OP-OA, O alpha, OA-OH, and OB via the bile, urine, and metabolic routes were 3.1, 3.6, 40, 65, and 43 ml/hr kg, respectively. OA, OB, and O alpha were mainly cleared in the urine (> or = 48%), OA-OH in the bile (41%), and OP-OA as metabolites (43%). Metabolism accounted for 43, 44, 33, and 29% of the total clearance of OA, O alpha, OA-OH, and OB, respectively. It is concluded that OA has a long half-life and is very slowly cleared from the body and that its metabolites are cleared at a much faster rate with much shorter half-lives. Procedures should be devised to enhance the conversion in the body of OA to O alpha, OA-OH, or other metabolites as this would shorten its half-life and therefore its toxicity.

Fumonisin B1 (FB1) and moniliformin (M) were supplied by Fusarium moniliforme M-1325 and Fusarium fujikuroi M-1214 culture material, respectively. Turkeys were fed a control ration, or rations containing 200 mg FB1/kg, 100 mg M/kg, or a combination of both 200 mg FB1/kg and 100 mg M/kg feed from 1 to 21 days of age. These rations contained 0, 3.8, 1.0, and 4.8% culture material, respectively. In comparison to controls, turkeys fed FB1 had increased relative liver weights. Both aspartate aminotransferase and lactate dehydrogenase were increased in poults fed FB1. Turkeys fed M had decreased feed intake and body weight gains and increased relative heart weights in comparison to controls. Poults fed FB1 had moderate diffuse hepatocellular hyperplasia and poults fed moniliformin had a loss of cardiomyocyte cross striations. Turkeys fed the ration containing both M and FB1 had all the above changes; however, no additive or synergistic effects were evident for any single parameter measured. No treatment-related morbidity or mortality was observed in the study.

A new method providing sensitivity to low concentrations was developed for the analysis of ochratoxin A in roast and ground and soluble coffee and a survey has been carried out to determine levels of ochratoxin A (OTA) in 100 samples of retail coffees available in the UK. The survey covered 80 soluble coffees (granulated, powdered, freeze-dried), of which nine products were decaffeinated, and 20 roast and ground retail coffee samples. OTA was detected (> or = 0.1 microgram/kg) in 64 samples of soluble coffee at levels ranging from 0.1 to 8 micrograms/kg. Seventeen samples of roast and ground coffee contained OTA at levels between 0.2 and 2.1 micrograms/kg. These results indicate that coffee products are not a major dietary source of OTA in the UK.

Male 5-week-old Wistar rats orally (po) administered with fusarenon-X (FX) 1.5 mg/kg and control rats po-treated with distilled water were sacrificed at 0-48 hr after gavage. FX-administered rats showed significant dilatation of the stomach with increased fluid contents at 1-24 hr postadministration (PA). Histopathologically, karyopyknosis of chief cells in the basal region of the gastric glands began to appear at 1 hr, and nuclear fragments were seen in the neck cell region at 1.5 hr PA. At 2-4 hr PA, apoptotic cells appeared diffusely in the neck region and focally in the basal region. Electron microscopy revealed that cells phagocytosing apoptotic bodies were the surface epithelia, undifferentiated neck cells, parietal cells and chief cells. No evidence was detected to show that parietal cells underwent apoptotic changes. The apoptotic lesions peaked at 4-6 hr PA, gradually subsided at 12 hr PA, and became minimal leaving apoptotic remnants in the basal region at 24 hr PA. At 48 hr PA, however, diffuse apoptotic lesions reappeared in the basal region at a level similar to that at 2-3 hr PA. This might be attributable to absorption of FX retaining in the stomach for 24 hr. In situ detection of DNA breaks by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction was consistent with the histopathologic findings. Agarose gel electrophoresis of DNA fragments isolated from the gastric mucosae of FX-administered rats showed a ladder pattern after 1.5 hr PA and the pattern became more distinct at 2-4 hr PA.

The individual and combined effects of feeding diets containing 100 mg moniliformin (M) and 3.5 mg aflatoxins (AF)/kg of diet were evaluated in male broiler chicks from day of hatch to 3 wk of age. When compared with controls, BW gains were reduced 29% by M, 13% by AF, and 33% by the M and AF combination. The efficiency of feed utilization was adversely affected by M independent of AF. Feeding M resulted in decreased relative weights of the bursa of Fabricius and increased relative weights of the heart, increased serum concentrations of creatinine and calcium, increased activities of alkaline phosphatase and alanine aminotransferase, and changes in hematological values. Feeding AF resulted in increased relative weights of the kidney and heart, decreased serum concentrations of total protein, albumin, cholesterol, and calcium, and decreased mean corpuscular volume. Feeding the combination of M and AF resulted in increased relative weights of the heart, decreased serum concentrations of total protein, albumin, and inorganic phosphorus, increased concentrations of creatinine and activity of alanine aminotransferase, and changes in hematological values. Results indicate additive or less than additive toxicity, but not toxic synergy, for most parameters when chicks are fed diets containing the combination of 100 mg M and 3.5 mg AF/kg of diet. The likelihood of encountering these high concentrations of these mycotoxins in finished feed is small; however, additional data on the naturally occurring concentrations of M are necessary before the importance of this mycotoxin to the poultry industry can be assessed.

The individual and combined effects of feeding diets containing 300 mg fumonisin B1 (FB1), and 4 mg diacetoxyscirpenol (DAS) or 3 mg ochratoxin A (OA) were evaluated in two experiments using female turkey poults (Nicholas Large Whites) from day of hatch to 3 wk of age. When compared with controls, body weight gains were reduced 30% (Study 1) and 24% (Study 2) by FB1, 30% by DAS, 8% by OA, 46% by the FB1 and DAS combination, and 37% by the FB1 and OA combination. The efficiency of feed utilization was adversely affected by all treatments except FB1 in Experiment 2. Relative weights of the liver were significantly increased by all treatments except the DAS treatment. Serum concentrations of cholesterol were decreased and activities of aspartate aminotransferase and lactate dehydrogenase were increased and several hematological values were altered in poults fed FB1 alone and in combination with either DAS or OA. Results indicate additive or less than additive toxicity, but not toxic synergy, when poults are fed diets containing 300 mg FB1, and 4 mg DAS or 3 mg OA/kg of diet. The likelihood of encountering FB1, DAS, or OA at these concentrations in finished feed is small. However, under field conditions, other stress factors could alter the impact of these mycotoxins on the health and performance of poultry.

Young pigs were fed diets to which 0, 2.5, or 5 mg/kg of purified nivalenol (NIV) had been added. The exposure continued for 3 weeks without any signs of feed refusal, vomiting, or change in clinical appearance, and there were no changes in body or organ weights due to the exposure. However, the concluding macroscopic examination revealed gastrointestinal erosions and signs of nephropathy in most of the exposed pigs. There were no differences in total or differential blood leukocyte counts between control and exposed pigs in blood samples collected after 0, 1, or 3 weeks, nor in the number of thymocytes at the end of the trial. Spleen cell numbers showed a dose-dependent decrease after 3 weeks of exposure that was statistically different from controls in pigs exposed to 5 mg NIV/kg. Flow cytometric analysis of lymphocytes revealed decreased numbers of both the CD4+ and the CD8+ subpopulations in the spleen at this point in time, reflecting the lower numbers of splenocytes; but no proportional changes were seen. In blood, exposure to NIV caused a transient decrease in the proportion of CD4+ cells after 1 week of exposure. Analysis of IgG and IgA in plasma showed a time-dependent tendency of increasing plasma concentrations of IgA and decreasing concentrations of IgG in the 2.5 mg/kg group, but differences in Ig levels between experimental groups and controls were not observed at any time. No differences were seen in the mitogen-induced proliferation by lymphocytes from blood, spleen, or thymus. In conclusion, exposure of young pigs to NIV in the diet caused pathological alterations in the kidneys and gastrointestinal tract and reduced the number of splenocytes. The results also indicated that exposure to NIV caused a time-dependent increase in IgA production in the 2.5 mg/kg group.