Acute and chronic effects of the trichothecene mycotoxin T-2 on rat brain regional concentrations of serotonin, tryptophan, and tyrosine.

Female rats were given 1 acute dose or chronic doses (once every 48 hr for 28 days) of T-2 toxin (10 micrograms/kg ip) or vehicle. At necropsy, each brain was subdivided into cerebellum, cerebral cortex (including telencephalon and diencephalon), and brainstem (including mesencephalon, metencephalon, and myelencephalon). Acute systemic T-2 toxin administration increased cerebellar and brainstem tryptophan while serotonin, a tryptophan metabolite, was decreased correspondingly in these same brain regions. Chronic T-2 administration increased cerebellar tyrosine and serotonin concentrations, while cortical tryptophan concentrations were also increased. These results indicate that both acute and chronic administration of T-2 toxin cause differential changes in regional distribution levels of tyrosine, tryptophan, and serotonin.

Differential changes in rat brain tryptophan, serotonin and tyrosine levels following acute aflatoxin B1 treatment.

Female Sprague-Dawley rats were treated acutely (12-h) with aflatoxin B1 (100 micrograms/kg i.p.) or vehicle (10% acetone in 0.9% NaCl) and regional brain levels of tryptophan, serotonin and tyrosine were assayed. Brainstem but not cerebellar or cortical tyrosine levels were decreased in aflatoxin B1-treated rats. Brain tryptophan was increased in all 3 brain regions by acute aflatoxin B1 treatment, while serotonin levels were unaltered in the cerebellum and cortex and decreased in the brainstem. These experiments indicate that acute aflatoxin B1 treatment differentially alters brain amino acids and serotonin and that changes in brain tryptophan, the serotonin precursor, do not parallel changes in brain serotonin.

Growth, Sporulation and Aflatoxin Production by Aspergillus parasiticus on Strained Baby Foods.

The potential for aflatoxin production by Aspergillus parasiticus on strained baby food was evaluated. Four puréed foods were inoculated with the mold and cultured at 15 and 26 C in two series of experiments. The aflatoxigenic mold produced mycelia and sporulated at both temperatures. The foods ranked in mean total yield of aflatoxin (µg/g of substrate) in the following order: peas > squash > green beans > pears. The ranking held consistent for both temperatures. Aflatoxins B1 and G1 were produced in higher percentages than B2 and G2 in each food at both temperatures. At 26 C, total aflatoxin produced ranged from 8 to 71 µg/g of substrate, and at 15 C, the mean for the four foods was from 3 to 50 µg/g of substrate. Temperature and substrate were the primary variables which contributed to sporulation rate, toxin production and toxin ratios. Peas and squash should be considered primary and highly supportive substrates for aflatoxin production if conditions should arise for spores to contaminate the products either during or after processing. Absolute prevention of aflatoxigenic spore contamination in these foods studied is essential. An occasional testing of these foods for aflatoxin seems warranted. A lower temperature during aflatoxin formation decreased the total toxin formed, but did not prohibit aflatoxin occurrence. A lower temperature also tended to divert the type of toxin produced from B1 to the less dangerous G1 and G2. Aflatoxin would appear to be a problem in these foods only under rare and unusual circumstances in relation to processing and consumer usage. If such aflatoxigenic spore contamination should occur, the levels produced would be significant.

Methylene blue and other agents as inhibitors of calcium oxalithiasis in vivo.

Growth of calcium oxalate on an established calculus upon a zinc nucleus in the bladder of rats was studied. Animals were fed either a regular solid chow or chow containing a potential crystal inhibitor ad libitum, along with drinking water containing 0.75 per cent ethylene glycol. Chow containing 0.2 per cent methylene blue and 0.5 per cent vitamin C not only decreased the growth rate, but calculi were much softer than those in controls. Safranin O was the only other significant growth inhibitor identified. Ethylenediamonotetraacetic acid and ethylenebis (oxyethylenenitrilo)-tetraacetic acid transformed the additional growth from the mono- to the dihydrate form of calcium oxalate.

The development of a test system for inhibition of urinary oxalate lithiasis.

The production of calcium oxalate deposits on zinc pellets in the bladder of rats was induced by the addition of 0.25 to 1.0 per cent ethylene glycol to their drinking water. Sprague Dawley rats requied more than 0.50 per cent ethylene glycol to produce calcium oxalate exclusively. The quantity of deposits varied widely between test animals, but intermediate operation to check on the amount of deposit showed that each rat at the 0.75 per cent ethylene glycol level maintained its individual rate of deposition within an acceptable standard deviation relative to the mean. At 1 per cent ethylene glycol deposition in the kidneys interfered with deposition on the zinc pellet.

Examination of fungal growth and aflatoxin production on marihuana.

Under favorable growth conditions, Aspergillus flavus and A. parasiticus produced aflatoxins on marihuana. Cultures of A. flavus ATCC 15548 produced both aflatoxin B1 (AFB1) and G1 (AFG1). The production of AFG1 was substantially greater than that of AFB1. Cultures of A. flavus NRRL 3251 and A. parasiticus NRRL 2999 produced only AFB1. All natural flora cultures tested negative for aflatoxins. No Aspergilli sporulations were observed in these cultures. In the cultures inoculated with known toxigenic fungi, the highest mean level for total aflatoxins was 8.7 microgram/g of medium. Marihuana appears not to yield large quantities of these mycotoxins but sufficient levels are present to be a potential health hazard for both the user and the forensic analyst who is in daily contact with such plant material. Careful processing, storage, and sanitation procedures should be maintained with marihuana. If these conditions are disregarded due to the illicit status of marihuana, the potential for mycotoxin contamination must be considered.