Ocular alkali burn associated with automobile air-bag activation. (65/69)

Alkali burns of the eye can result in permanent visual impairment and are therefore potentially devastating. Immedicate diagnosis and treatment are essential to a good prognosis. The authors report the case of a 52-year-old woman who suffered alkali keratitis as the result of the activation of an automobile air bag. This type of injury will be seen more frequently as more cars are equipped with air bags and should be suspected in drivers and passengers involved in accidents in which air bags have been activated.  (+info)

The effect of dialysate acidity on peritoneal solute transport in the rat. (66/69)

OBJECTIVE: To investigate the possible effect of unphysiologically low pH in dialysis fluid on peritoneal transport. DESIGN: A 4-hour single-cycle experimental session of peritoneal dialysis was performed in six Sprague-Dawley rats using Dianeal 3.86% solution modified by adding 5 mmol/L of sodium hydroxide, neutral pH solution (NpHS) (pH 7.4). The intraperitoneal volume (VD) and peritoneal bulk fluid reabsorption (Qa) were calculated using a marker, 131I-labeled human serum albumin (RISA). The diffusive mass transport coefficient (KBD) as well as sieving coefficient (S) for glucose, urea, sodium, and potassium were calculated using the Babb-Randerson-Farrell model. The same study was performed in seven rats using Dianeal 3.86% solution, acidic pH solution (ApHS) (pH 5.7) to provide control values. RESULTS: The dialysate pH was stable with NpHS; 45 min after the infusion of ApHS it increased rapidly and reached the physiological value 7.4. Dialysate volume and KBD values for sodium and potassium with NpHS were significantly higher than with ApHS, while the KBD values for glucose and urea did not differ between the two solutions. S values for sodium and urea did not differ between the two solutions, while the values for glucose and potassium with NpHS were significantly higher and lower, respectively, than the values with ApHS (0.92 +/- 1.04 vs 0.04 +/- 0.63 and 0.56 +/- 060 vs 1.15 +/- 0.39, p < 0.05). The absorption of glucose from the dialysis solution expressed as a percentage of the initial amount of dialysate glucose was significantly lower with NpHS than with ApHS at 30 min (17.3 +/- 1.7% vs 29.7 +/- 2.0%, p < 0.05). CONCLUSION: We conclude that the peritoneal transport of fluid and small solutes might to some extent be influenced by the acidity of the dialysis solution. The vasodilatory effect of acidic dialysis solution might be the most important mechanism for these differences. However, a larger KBD value and a lower S value for potassium and higher S values for glucose during dialysis with the neutral dialysis solution may indicate that transport mechanisms other than simple passive transport are involved in peritoneal transport for glucose and electrolytes.  (+info)

Inhibition of potassium dichromate mutagenicity by todralazine. (67/69)

Todralazine, an antihypertensive drug of the hydrazinoph-thalazine group, markedly decreased the mutagenic activity of potassium dichromate in standard bacterial tests. At the highest todralazine dose tested inhibition of potassium dichromate mutagenic activity by approximately 90% in the Ames test and up to 100% (complete) inhibition in the Bacillus subtilis rec- assay was observed. Spectrophotometric analyses proved that todralazine induced reduction of Cr(VI) to Cr(III) and complexation of Cr(III) ions. These spectro-photometric results may be a presumptive explanation of the observed mutagenic activity decrease, as it is known that Cr(III) is poorly transported across cell membranes and therefore is not mutagenic to bacterial cells. We perceive our experiments as an example of attempts which should lead to an effective reduction in chromium genotoxic and carcinogenic activity in exposed individuals.  (+info)

The structure of interfibrillar proteoglycan bridges (shape modules') in extracellular matrix of fibrous connective tissues and their stability in various chemical environments. (68/69)

Collagen fibrils in extracellular matrices of connective tissues (tendon, cornea, etc.) are bridged and linked by the anionic glycosaminoglycans (AGAGs) of the small proteoglycans (decoron, etc.). It was proposed that these bridges and ties maintain the collagen fibril dispositions in relation to each other, helping to define tissue shape, and hence called shape modules. This investigation describes chemical and physicochemical conditions in which these structures are stable and what treatments cause their disruption. The effects on fixed and unfixed sections of tendon, cornea, lung and ear from rat, mouse and rabbit of pH, electrolyte concentration, EDTA, mercaptoethanol, hydrogen peroxide, free radicals, periodate, acetylation, urea, nonionic detergent and organic solvents were assessed by staining with Cupromeronic blue or Alcec blue in CEC techniques to localise AGAG bridges or their disintegration products. Ca2+ was not involved in the structures, oxidation/reduction had no effect and Triton X100, a nonionic detergent did not damage them. They were stable between pH 4.5 and 9.5. Periodate as a glycol-cleaving reagent did not affect them. High concentrations of urea (> 2.0 M) and MgCl2 (0.5 M) disrupted the tissues. The combination of Triton and urea at concentrations too low to cause damage separately was disruptive. Free radicals in periodate solutions were damaging. Organic solvents caused collapse and rearrangements of the AGAG filaments. Acetylation caused considerable disruption of shape modules. Dermochondan but not keratan sulphate AGAGs were removed by treatment with NaOH. After fixing with glutaraldehyde only free radical and NaOH treatments were severely disruptive of shape modules. The results are compatible with a previously proposed structure for the shape modules, stabilised by hydrophobic and hydrogen bonding.  (+info)

Quantification of surface defects on chemically protective gloves following their use in agriculture. (69/69)

Chemically protective gloves are one of the most widely used barriers against hand exposure to pesticide contamination available to workers in primary industry. Polyvinyl chloride and nitrile butadiene rubber gloves were collected from four typical agricultural enterprises in Tasmania. Surface images of new and used gloves, up to 1000 x magnification, were obtained from an environmental scanning electron microscope and were used to classify defects, such as cracks, crazes, cavities, convexities, smooth areas and slumps. Some defects, e.g. cracks, were related to the working life of the gloves, whereas others, e.g. slumps, were associated with the manufacturing process. After viewing, the gloves were analysed by X-ray energy-dispersive spectroscopy. Phosphorus and sulfur peaks were indicative of pesticide retention. Rinsates from the interior of used polyvinyl chloride gloves were analysed by gas chromatography and mass spectrometry. Pesticide traces were found suggesting inadequate protection against dermal exposure. It is concluded that these gloves were unable to withstand the rigours of agricultural work because of the nature of the surface defects and they were contaminated with pesticides, outside and inside. Thus, their management needs improvement.  (+info)