C. Gregotti

Isolation of high molecular weight components and contribution to the protective activity of coffee against lipid peroxidation in a rat liver microsome system.

One of the most extensively studied and best-established properties of coffee is its antioxidant activity. We have shown that coffee brew has the ability to inhibit lipid peroxidation completely in a rat liver microsome biological system. The inhibitory activity was mainly due to the high molecular weight (HMW) fraction; this consisted of five components that were isolated, purified, and seen to occur in different amounts in the brew. Each component had different spectra and element compositions, although they all contained nitrogen. HMW, nitrogen content, and brown color enabled three components to be attributed to the melanoidin family; the two nonbrown components could not be considered as melanoidins. Each melanoidin and nonmelanoidin component contributes to a different extent to the protective action exerted by coffee brew. None of the isolated components completely inhibited microsomal lipid peroxidation alone, suggesting that each acts at different sites and/or possesses different mechanisms of action. The protective activity of coffee brew is thus underpinned by the antiradical properties, reducing power, and metal chelating ability of the individual components, each contributing to a different extent.

In vitro and ex vivo anti- and prooxidant components of Cichorium intybus

The water soluble antioxidant properties of Cichorium intybus var. Silvestre, whose production zone is around Chioggia, Italy, were investigated. Vegetable juices were obtained by centrifugation, and (1) filtration at 2 degrees C; (2) filtration at 25 degrees C, and stored for 3 h; (3) boiled for 30 min at 102 degrees C, and then analysed. The antioxidant properties were evaluated in vitro as antioxidant activity (AA) (model system beta-carotene-linoleic acid) and ex vivo as protective activity (PA) against rat liver cell microsome lipid peroxidation measured as 2-thiobarbituric acid-reactive substances (TBA-RS) generated by peroxide degradation. All the vegetable juices showed high but very variable AA (> 83%) and PA (> 64%). After dialysis and analysis of fractions it was shown that the vegetable contained both biological antioxidant and prooxidant compounds. The prooxidants had MW < 3000, conversely the very active antioxidants (PA = 100%) had MW > 15,000. Electrophoretic analysis revealed that the most active fraction was a complex mixture of brown components at MW > 300,000.

Effects of thallium on primary cultures of testicular cells

The objective of this in vitro study was to examine the response of mixed cultures of Sertoli and germ cells to treatment with thallium (Tl) at the range of concentrations that, in previous studies, was shown in vivo to affect reproduction. Cultures were prepared from the testis of Sprague-Dawley rats. Cultures containing approximately 3.75 x 10(6) cells/ml were treated with Tl concentrations corresponding to 35, 7, and 1.4 micrograms Tl/g testis, estimated from protein content of cultures. Observations at 24, 48, and 72 h after treatment showed a significant release of germ cells into the culture medium that was both concentration and time dependent. Cultures treated with 35 micrograms Tl/g testis showed a threefold increase in germ-cell detachment compared with controls after only 24 h of exposure. As the treatment time increased to 48 h of exposure, even cultures exposed at the lowest Tl concentration (1.4 micrograms Tl/g testis) showed significant loss of germ cells. After 48 h, cultures exposed to 7 micrograms Tl/g testis exhibited a 2.5-fold increase in germ-cell detachment, and those exposed to 35 micrograms Tl/g testis exhibited a 10-fold increase over controls. Morphological investigations of cell cultures showed evident loss of germ cells with significant reduction in prepachytene and pachytene spermatocytes and changes in the shape of Sertoli cells. These results are in agreement with in vivo studies, in which thallium treatment at comparable exposure levels manifested its earliest toxic testicular effects in Sertoli and germ cells. They also demonstrate the usefulness of this in vitro culture technique to assess toxic testicular damage rapidly.

Thallium-induced testicular toxicity in the rat

Reproductive tract functions were studied in adult male Wistar rats given 10 ppm thallium as thallium sulfate in the drinking water. After 60 days of treatment, spermatozoa isolated from the cauda epididymides and vas deferens showed reduced motility and immature germ cells were found in the tubular lumen. Histological examination of testes in thallium-treated animals revealed disarrangement of the tubular epithelium and ultrastructural changes in the Sertoli cells with cytoplasmic vacuolation and distension of the smooth endoplasmic reticulum. The activity of testicular beta-glucuronidase was significantly reduced whereas acid phosphatase and sorbitol dehydrogenase activities were unchanged. Plasma testosterone levels were within normal limits. No abnormalities in testicular morphology and biochemistry were seen in animals sacrificed at the end of the first month of thallium exposure. These findings indicate that the male reproductive system is a susceptible target site to toxic effects of thallium under chronic exposure. They also suggest a major involvement of Sertoli cells in the mechanism underlying thallium-induced testicular damage.

Effects of Phenobarbitone on the Distribution, Metabolism and Biliary Excretion of Erythromycin in Rats

The administration of phenobarbitone to the rat (8 mg/100 g BW) once daily for 3 days significantly decreased the serum and tissue levels of erythromycin administered intraperitoneally (5 mg/100 g BW). Furthermore, phenobarbitone stimulated the hepatic microsomal N-demethylation of erythromycin and increased the biliary concentration and the biliary excretion rate of the unmetabolized antibiotic. These effects were accompanied by augmented liver mass and bile flow. The possibility is discussed that erythromycin concentrates in the bile through a specialized hepatic drug transport system, activated by phenobarbitone.

Effects of thermal water on skin regeneration

An experimental study was carried out in an animal (New Zealand white rabbit) wound model to evaluate any effects of a hypotonic, bicarbonate-calcium-magnesium mineral water (Comano thermal water) on skin regeneration, comparing the healing rate of split-thickness skin graft donor sites treated with the thermal water wet dressing versus a standard petrolatum gauze dressing versus a saline solution wet dressing. The study was performed in two steps; an overall of 22 animals were enrolled in the study. The wound healing progress was evaluated both by the surgeons and by the histologists. Sixty-four punch biopsies were examined in all. The histological samples were examined after staining with haematoxylin and eosin, Massons and orcein staining and under a transmission electron microscope. The data were statistically analysed. The Comano thermal water proved to improve skin regeneration, not only by increasing keratinocyte proliferation and migration but also favourably modulating the regenerated collagen and elastic fibres in the dermis. We propose that the results of the topical treatment with the thermal water could be due to the favourable combination of a local wet environment with an anti-inflammatory action and that the regenerative properties of Comano thermal water observed in rabbits could also be applied for human use.

1,2-Dichloropropane-Induced Liver Toxicity: Clinical Data and Preliminary Studies in Rats

1,2-Dichloropropane (DCP) is an industrial solvent widely used as a component of household dry-cleaning products, in the paint industry, and in agriculture as a soil fumigant. In recent years, intoxications and fatalities have been described as the result of abuse (“sniffing”) and accidental or deliberate ingestion of commercial household products containing varying concentrations of DCP (Pozzi et al. 1985). Clinical features of poisoning by DCP-containing products have included blood disorders, renal failure, and hepatic damage (Ghezzi Laurenzi et al. 1987).

Organ/tissue disposition of thallium in pregnant rats.

The placental transfer of thallium was studied in rats treated with a toxic dose of thallium sulphate (10 mg Tl/kg b.wt. p.o.), as well as in animals injected intraperitoneally with 201Tl-labelled thallium in amounts as low as 2 micrograms Tl/rat. Rapid uptake and retention of thallium in both maternal and fetal organs were observed. The administration of potassium ferrihexacyanoferrate II (100 mg/kg b.wt. twice daily by gavage) to rats acutely intoxicated with thallium on day 17 of pregnancy resulted in significant decrease of thallium concentrations in various maternal tissues including brain, in the placenta as well as in the fetal liver and brain. Potassium ferrihexacyanoferrate II also reduced the mortality of pregnant animals in the 72-h interval after the intoxication.

Triphenyl Tin Hepatotoxicity in Rats

Hepatic microsomal aniline hydroxylase and aminopyrine N-demethylase in vitro activities and the biliary excretion of sulfobromophthalein (BSP) were significantly reduced in rats treated with triphenyl tin (TPT) in daily doses of 1 mg/kg i.p. for 3 days. Bile flow, liver weight, serum enzyme activities, and hepatic sulfhydryl groups and thiobarbituric reactant levels were unaffected in TPT-treated animals. Moreover, TPT failed to induce any appreciable change in the biliary excretion of both the organic base procainamide ethobromide and the organic acid amaranth which is excreted into the bile in the unmetabolized form. TPT has been shown to be an effective inhibitor of rat liver glutathione-S-transferase activity. Reduced conjugation with glutathione may play a role as a factor determining the low rate of biliary BSP excretion in the TPT-treated rats.

Intestinal Absorption and Excretion of Thallium (201Tl) in the Rat

The gastrointestinal transport of 201Tl-labelled monovalent thallium has been studied in normal and rats with cannulated bile ducts using an in vivo ligated loop technique. A marked difference in the Tl absorptive capacity among the various sections of the gut was observed. 201Tl was taken up more quickly from the colon than from any other segment and the uptake from the ileum and jejunum was higher than from the stomach. In addition, considerable amounts of the intravenously administered thallium were excreted into the intestinal lumen. The biliary excretion was very low compared with the direct transfer of 201Tl across the gastrointestinal wall that occurred against a tissue-to-plasma concentration gradient. In the rat, the large intestine seems to be the major area for the enteral reabsorption and recycling of thallium (I) ions.