Effect of parenteral zinc sulfate on colon anastomosis repair in the rat.

BACKGROUND AND AIMS: To prevent colonic anastomotic dehiscence, pharmaceutical interventions should inhibit degradation of existing submucosal collagen fibers and accelerate the synthesis of new collagen molecules. Zinc has multiple functions in collagen metabolism and was recently found beneficial in colonic anastomosis repair. We have investigated the effect of daily intraperitoneal zinc (2 mg/kg) injections on the development of the biomechanical integrity of left colon anastomoses. MATERIALS AND METHODS: Sixty Sprague-Dawley male rats (median 245 g) were allocated to treatment with zinc sulfate in saline (n = 30) or with saline alone (n = 30) starting 1 h before the anastomoses were made. Serum zinc levels and anastomotic breaking strength were determined on postoperative days 3 (n = 30) and 7 (n = 30). The initial breaking strength or suture-binding capacity was determined in additional ten non-treated animals (277 g). RESULTS: The breaking strength of the anastomoses decreased in the two groups combined (n = 30) by 50% (p < 0.001) on day 3 but was regained by postoperative day 7 compared with the initial anastomotic biomechanical strength. Serum zinc levels also increased from day 3 to day 7 in both intervention groups and correlated significantly with breaking strength (r = 0.57, p < 0.001). Although the median serum zinc level was 14% higher (p < 0.01) on day 7 in zinc-treated than in saline-treated animals, the breaking strength did not differ significantly between zinc-treated and saline-treated rats on either day 3 (p = 0.95) or day 7 (p = 0.70). CONCLUSION: In contrast to previous report in rabbits, we failed to demonstrate the beneficial effects of parenteral zinc supplementation on colon anastomosis repair in a rat model.

Inhibitory effects of tannin on human salivary alpha-amylase.

Here, we first report on the effectiveness and specificity of tannin inhibition of 2-chloro-4-nitrophenyl-4-O-beta-d-galactopyranosylmaltoside hydrolysis that is catalyzed by human salivary alpha-amylase (HSA). Tannin was gallotannin in which quinic acid was esterified with 2-7 units of gallic acid. A number of studies establish that polyphenols-like tannins-may prevent oral diseases, e.g., dental caries. Kinetic analyses confirmed that the inhibition of hydrolysis is a mixed non-competitive type and only one molecule of tannin binds to the active site or the secondary site of the enzyme. Since Dixon plots were linear, product formation could be excluded from the enzyme-substrate-inhibitor complex (ESI). Kinetic constants calculated from secondary plots and non-linear regression are almost identical, thereby confirming the suggested model. Kinetic constants (K(EI) = 9.03 microgmL(-1), K(ESI) = 47.84 microgmL(-1)) show that tannin is as an effective inhibitor of HSA as acarbose and indicate a higher stability for the enzyme-inhibitor complex than ESI.

Investigation of excretion and absorption of different zinc salts in puppies.

The effects of dietary zinc on zinc absorption and excretion were evaluated with six 12-week-old beagles. The dogs were fed a commercial dry food later supplemented with 2 and 4mg/kg of body weight per day of either zinc sulphate, zinc acetate or zinc oxide. The concentrations of zinc in the urine and faeces of all treatment groups were increased depending on the type of zinc salts and the dosage in the diet (P < 0.05). The apparent absorption of zinc salts ranged from 0.20 to 0.36. The zinc salt supplements at both dosages did not affect the digestibility of crude protein, fat and fibre. The zinc concentration in plasma varied with the type of zinc salt and with the dosage. The mean concentrations ranged from 61+/- 1.46 microg to 73 +/- 1.57 microg/dl in the unsupplemented groups, whereas it was 115 +/- 2.33 microg/dl in the group supplemented with zinc acetate at the highest dosage.

Mitochondrial cytochrome c oxidase subunit III is selectively down-regulated by aluminum exposure in PC12S cells.

Aluminum (Al) has been implicated in several neurological diseases including dialysis dementia and Alzheimer's disease (AD). One possible mechanism of Al neurotoxicity could involve alteration of mitochondrial gene expression. We exposed PC12 cells to 0.1-100 microM AlCl3 for 6h at pH 7.4. Internalized Al, measured by atomic absorption spectrometry, was linearly proportional to the extracellular Al concentration. Northern blot analyses showed that cytochrome c oxidase subunit III (COX III) mRNA was significantly reduced by 70% after addition of 1 microM AlCl3. Higher concentrations of AlCl3 did not show a significant further effect. These results suggest that Al neurotoxicity involves a specific impairment of cytochrome c oxidase.

Absorption and elimination of trivalent and hexavalent chromium in humans following ingestion of a bolus dose in drinking water.

These studies investigate the magnitude and valence state of chromium absorbed following plausible drinking water exposures to chromium(VI). Four adult male volunteers ingested a single dose of 5 mg Cr (in 0.5 liters deionized water) in three choromium mixtures: (1) Cr(III) chloride (CrCl3), (2) potassium dichromate reduced with orange juice (cr(III)-OJ); and (3) potassium dichromate [Cr(VI)]. Blood and urine chromium levels were followed for 1-3 days prior to and up to 12 days after ingestion. The three mixtures showed quite different pharmacokinetic patterns. CrCl3 was poorly absorbed (estimated 0.13% bioavailability) and rapidly eliminated in urine (excretion half-life, approximately 10 hr), whereas Cr(III)-OJ was absorbed more efficiently (0.60% bioavailability) but more slowly (half-life, approximately 17 hr), and Cr(VI) had the highest bioavailability (6.9%) and the longest half-life (approximately 39 hr). All three chromium mixtures caused temporary elevations in red blood cell (RBC) and plasma chromium concentrations, but the magnitude and duration of elevation showed a clear trend (Cr(VI) > Cr(III)-OJ > CrCl3). The data suggest that nearly all the ingested Cr(VI) was reduced to Cr(III) before entering the bloodstream based on comparison to RBC and plasma chromium patterns in animals exposed to high doses of Cr(VI). These findings support our prior work which suggests that water-soluble organic complexes of Cr(III) formed during the reduction of Cr(VI) in vivo explain the patterns of blood uptake and urinary excretion in humans at drinking water concentrations of 10 mg/liter or less.

Astringent subqualities in acids.

Astringency, astringent subqualities (drying, roughing and puckering) and sourness were compared among six acids: hydrochloric, lactic, citric, acetic, fumaric and malic acids. The attribute profiles of organic acids were similar to each other but different from hydrochloric acid, the only inorganic acid, which was the most astringent and the least sour. In a second experiment, two inorganic acids (hydrochloric and phosphoric) and two organic acids (citric and malic) were tested at three concentration levels. At approximately equal levels of overall sensory impact, the inorganic acids were alike in astringency and sourness, receiving higher ratings for roughing and drying, and lower ratings for sourness than the organic acids. Interactions with concentration (differences in psychophysical functions) for the subquality of drying were noted, in addition to the differences in the astringent subqualities of roughing and drying seen across acids in both experiments. The higher level of astringency for inorganic acids suggests that the current model for tannin binding to salivary proteins as an explanation of astringency needs to be extended to include a direct pH-dependent effect.

[Modern cosmetic agents and evidence of their function]. / Moderne kosmetische Wirkstoffe und der Nachweis ihrer Funktion.

Fluorometers modified by quartz light conductors allow the recording of the skin-intrinsic fluorescence. Signals assigned to the aromatic amino acids permit a prognosis concerning the sensitivity of untreated skin to light and the sunscreen factor to be expected after the application of UV filters. We discuss the microdistribution and skin penetration of UV filters and describe the utilization of the image analysis technique both for the count and size determination of fluorescent sebaceous glands and for the quantification of the effects of antiperspirants. Based both on the selective increase of efficacy of deodorant soaps, analytically controlled, and on the differences of the deodorizing effects found in various test groups, we discuss the possibilities of improving deodorants.