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PubMedDate not supplied

Circadian rhythms of RNA, DNA and protein content in the rat thyroid, adrenal and testis in chronic pesticide exposure. I. Effects of a fungicide (Mancozeb).

Ninety days of exposure to the fungicide Mancozeb, 100 ppm/day, affects the circadian rhythms of RNA, DNA and proteins in the thyroid and adrenal and slightly but statistically significantly, the testicular RNA content in the rat. The thyroid RNA rhythm shows an almost 12-hour phase advance without change in mesor, but with a decrease in amplitude and in the percent of total variability of RNA in the group, attributable to the circadian rhythm (PR). In the adrenal, the circadian rhythm of RNA and DNA is lost as a group phenomenon and the mesor of the circadian rhythm of protein content is elevated. The testicular RNA rhythm shows multiple peaks, suggesting frequency demultiplication and a loss of the circadian rhythm as a group phenomenon. Chronotoxicology appears to be essential in detecting the adverse effects of pesticides.

Adrenal Glands↗
PubMed1994

Vitamin C mediated amelioration of pesticide genotoxicity in murine spermatocytes.

The effect of vitamin C on the genotoxicity of three pesticides (Endosulfan, Phosphamidon, Mancozeb) was monitored by screening meiotic (metaphase I) chromosomes in the primary spermatocytes of Swiss albino mice, Mus musculus. A dose-dependent amelioration by vitamin C was observed in the Phosphamidon-treated group where quadruple the therapeutic dose produced maximum amelioration. In Endosulfan- and Mancozeb-treated groups, no further amelioration was achieved beyond the double dose of vitamin C, and the damage frequency did not come down to the control level. The possible mechanism of this effect is discussed.

Animals↗
PubMedDate not supplied

[Allergic diseases caused by pesticides: 3 case reports].

Current pesticide exposure levels can induce a state of sensitization in exposed workers and only in exceptional situations cause severe intoxication. Three cases are reported--one suffering from urticaria/angio-edema, one from asthma and the other from oculo-rhinitis. Only one subject was atopical. The substances to which sensitization was found were Cynoxamil, Mancozeb, Thiophanate, Seccatutto for the first case, Paraquat for the second and Dodine for the third subject. The results suggest the need to extend allergological tests also to pesticides when workers, or subjects in any case exposed, show clinical signs with suspected immunological pathogenesis. Furthermore, in order to reduce the number of new cases of pesticide allergy, a more severe control also of subjects exposed to low doses is proposed.

Angioedema↗
PubMed1993

Age-related effects in the inhibition of oxidative metabolism of xenobiotics by mancozeb.

The effect of po administration of 100 or 200 mg mancozeb/kg body weight for 7 consecutive days on microsomal mixed-function oxidase catalyzed xenobiotic metabolism was investigated in the livers of newborn weanling and adults rats. Mancozeb caused a dose-dependent inhibition in the activities of p-nitroanisole O-dealkylase and aniline hydroxylase, while the activities of aminopyrine N-demethylase and benzo(a)pyrene hydroxylase were unaffected in all the age groups. The inhibition of p-nitroanisole O-dealkylase and aniline hydroxylase, was remarkably higher in adult than in newborn and weanling rats. There was a concentration-dependent decrease in cytochrome P-450 and microsomal protein contents. This study indicates selective age-independent inhibition of hepatic monooxygenases following repeated mancozeb dosing.

Age Factors↗
PubMedDate not supplied

[Dosage indicators in farm workers exposed to mancozeb].

A study was performed on a group of farm workers exposed to mancozeb to validate dose indicators. Two indirect methods have been employed to monitor the air-dispersed mancozeb in the working environment (average concentration 57.2 micrograms/Nm3): carbon disulfide and manganese dosage. The latter proved to be more applicable. To assess skin contamination, the concentration of mancozeb was measured on pads placed on work overalls and in the liquid employed to wash workers' hands. Average concentrations of 0.86 microgram/cm2 and 641 micrograms respectively were obtained. A good correlation between mancozeb concentration on pads and in the air was found. Urinary ethylenethiourea (ETU) and manganese measured before and after a three day exposure were selected as indicators for internal dose. In all cases except three (2.9-2.3 and 4.4 mg/g creat.) ETU was below the sensitivity limit of the method employed. Urinary manganese increased from a mean of 0.32 microgram/g creat. to a mean of 0.53 microgram/g creat. after the exposure. The correlation with environmental data was r = 0.667.

Adult↗
PubMedDate not supplied

[Evaluation of urinary excretion of ethylenethiourea in subjects occupationally and non-occupationally exposed to ethylenebis(dithiocarbamates)].

Ethylenebisdithiorcabamate (EBDC) fungicides are broken down metabolically and in the environment to ethylenethiourea (ETU), a suspected carcinogen. Urinary ETU was assayed in control groups and subjects occupationaly exposed to EBDC and was found to be an excellent indicator of exposure both to ETU and EBDC. Correct use of protective clothing greatly reduced exposure and urinary excretion of ETU. ETU was excreted, albeit in low concentrations, in a high percentage (91% and 30%) of subjects in both control groups, demonstrating its utility as an indicator of widespread EBDC contamination.

Agricultural Workers' Diseases↗
PubMed1976

Helical structure of human native collagen.

A "fibroleiomyoma" of the lung obtained from a 40-year-old man as a surgical specimen was studied with both the light and the electron microscope. The unusual collagen in this tumor displayed a filamentous helical structure. The filaments measured 50 Angstroms across. Most of the fibrils did not show periodicity. Some, however, showed periodicity of about 700 A. Those with periodicity were smaller in diameter than the fibrils without periodicity. These observations suggest a helical structure of native collagen and may also represent weak cross-linking of tropocollagen in this tumor. This is the first report of collagen showing a helical filamentous structure from human material.

Adult↗
PubMed1999

Dithiocarbamate pesticides affect glutamate transport in brain synaptic vesicles.

Dithiocarbamate compounds are widely used agricultural fungicides that display low acute toxicity in mammals and that may become neurotoxic after prolonged exposure. Mancozeb, among other dithiocarbamates tested, proved to be the most potent (Ki= 0.27 microM) at noncompetitively inhibiting the in vitro ATP-dependent uptake of [3H]glutamate in rat cortical vesicles. Furthermore, mancozeb partially (20%) inhibited the ATP-dependent uptake of [14C]methylamine, used as an index for the vesicular transmembrane proton gradient (DeltapH), and evoked its efflux from organelles previously incubated with the 3H-labeled marker. Meanwhile, the vesicular uptake of 36chloride- anions whose concentrations regulate the transmembrane potential gradient (DeltapsiSV) was not impaired. The dithiocarbamate effects on the vesicular transport of [3H]glutamate thus appeared to involve mainly the DeltapH gradient rather than the potential gradient. Dithiocarbamate metabolites, the potent neurotoxin carbon disulfide included, did not affect the uptake process, thus implying the relevance for inhibition of the persistence, if any, of parent compounds in the brain. The present novel and potent in vitro interferences of selected dithiocarbamate pesticides with the vesicular transport of glutamate, if representative of in vivo alterations, may play some role in the probably complex origin of dithiocarbamate neurotoxicity.

Adenosine Triphosphate↗