Search

The water treatment plant in Haverhill, MA, collects extensive process data: detailed Supervisory Control and Data Acquisition (SCADA) system data and manually recorded operator data on flow, raw water quality, [...]

Water treatment plants routinely record flow, raw water quality, chemical feed, turbidity and finished water quality data. Laboratory, operations and equipment data may be collected continuously by a Supervisory Control [...]

The nephrotoxic potential of amphotericin B (5 mg/kg per day intraperitoneally for 3 weeks) has been investigated in salt-depleted, normal-salt, and salt-loaded rats. In salt-depleted rats, amphotericin B decreased creatinine clearance linearly with time, with an 85% reduction by week 3. In contrast, in normal-salt rats creatinine clearance was decreased but to a lesser extent at week 2 and 3, and in salt-loaded rats creatinine clearance did not change for 2 weeks and was decreased by 43% at week 3. All rats in the sodium-depleted group had histopathological evidence of patchy tubular cytoplasmic degeneration in tubules that was not observed in any normal-salt or salt-loaded rat. Concentrations of amphotericin B in plasma were not significantly different among the three groups at any time during the study. However, at the end of 3 weeks, amphotericin B levels in the kidneys and liver were significantly higher in salt-depleted and normal-salt rats than those in salt-loaded rats, with plasma/kidney ratios of 21, 14, and 8 in salt-depleted, normal-salt, and salt-loaded rats, respectively. In conclusion, reductions in creatinine clearance and renal amphotericin B accumulation after chronic amphotericin B administration were enhanced by salt depletion and attenuated by sodium loading in rats.

Between November 1983 and January 1984, 13 cases of Candida parapsilosis endophthalmitis occurred in Florida, Georgia, and Tennessee in patients who had had an intraocular lens implantation (IOLI) or cataract extraction with an IOLI. This outbreak followed the introduction in July 1983 of a new brand of balanced salt solution (BSS) used as an intraoperative ophthalmic irrigation solution. This product was subsequently recalled because of intrinsic fungal contamination. A retrospective cohort study including 704 ophthalmology patients at risk for exposure to this brand of BSS revealed that definite exposure to that product was a significant risk factor for C. parapsilosis endophthalmitis (P less than 0.001, Fisher exact test). A retrospective case control study including 203 control patients with definite exposure to BSS suggested that exposure to systemic steroids (P = 0.007, Fisher exact test) was an additional risk factor for C. parapsilosis endophthalmitis. Treatment modalities among the 13 patients included topical, intraocular, or systemic antifungal therapy (or a combination of these modalities) in 13 patients and vitrectomy in 10 patients. No patients had systemic symptoms or complete visual loss. Laboratory investigations showed a 6.7% overall contamination of the product with C. parapsilosis. After recall of the product by the manufacturer, no patients having a cataract extraction or IOLI at the institutions studied are known to have developed C. parapsilosis endophthalmitis.

Mature male and female mice 50 days of age were challenged with i.v. sodium arachidonate at doses of 12.5, 25, 50 and 100 mg/kg. A dose-dependent response in terms of mortality was observed. Males were significantly more susceptible to arachidonate-induced mortality than females at the 25 and 50 mg/kg doses (P less than .05). The 100 mg/kg dose produced 100% mortality in both sexes. When mice aged 23, 29, 35 and 50 days were challenged with 50 mg/kg of arachidonate, no gender difference was observed until mice were 35 days of age, at which time the male mortality was 80%, compared to 57% for female mice (P less than .05). Mice gonadectomized at 23 days and intact mice 23 days of age were treated with s.c. estradiol, testosterone or vehicle for 7 days before arachidonate challenge. Among these groups, the gonadectomized females and intact males were significantly protected by estradiol when compared to the appropriate controls (P less than .05). In contrast, testosterone pretreatment had no significant effect on mortality. These results demonstrate that the development of the gender difference in arachidonate-induced mortality in mice is dependent upon the presence of gonadal hormones in the immature stages.

Calcofluor White ST was used to monitor the morphological events in the biogenesis of cellulose in the microcyst wall of the wild-type strain (WS-320) and two developmental mutants (mic-1 and mic-2) of Polysphondylium pallidum. During encystment, the cell surface acquires a Calcofluor-specific material which appears to be cellulose because of its sensitivity to purified cellulase. Cellulose-containing vesicles appear distributed throughout the cytoplasm of encysting cells of the three strains. Later, the cellulose-rich vesicles appear near the cell surface. Subsequently, the cell surface stains with Calcofluor, and the vesicles are no longer detectable. Intracellular vesicles resembling the cellulose-rich vesicles in size, in the timing of appearance, and in cellular location are also seen in thin sections. These vesicles are surrounded by a single unit membrane, and their amorphous matrix, which contains a dense irregular core, further implicates them as the basis for the bilayered microcyst wall.

Extracts of dormant microcysts of Polysphondylium pallidum demonstrate pH optima for the hydrolysis of casein at 3.5 and 6.0. During germination the intracellular pH 6.0 caseinolytic specific activity does not change significantly. The pH 6.0 protease is also active on azo-albumin, revealing the same developmental pattern with this substrate. Both acid protease activities are excreted during the germination process. Addition of purified nonspecific protease to cultures speeds up germination, suggesting that the excreted protease may play a role in removal of the microcyst wall. When cycloheximide is added to cultures, complete germination (emergence) is stopped whereas the pH 6.0 protease activity still accumulates to between 50 and 60% of the maximum control activity. Although this suggests that post-translational controls might mediate the accumulation of a portion of the pH 6.0 protease increase, mixing and dilution experiments with cell extracts do not reveal the differential presence of soluble activators or inhibitors of this activity at different developmental stages. The presence of tightly bound enzyme-inhibitor complexes for protease B in dormant microcysts has not been ruled out and is currently under study.