Determination of the fate of alcohol ethoxylate homologues in a laboratory continuous activated-sludge unit study

Environmental monitoring indicates that the distribution of alcohol ethoxylate (AE) homologues in wastewater treatment plant (WWTP) effluents differs from the distribution in commercial AE products, with a relative higher proportion of fatty alcohol (AOH, which is AE with zero ethoxylation). To determine the contribution of AE-derived AOH to the total concentration of AE and AOH in WWTP effluents, we conducted a laboratory continuous activated-sludge study (CAS). This consisted of a test unit fed with AE-amended synthetic sewage and a control unit fed with only synthetic sewage to avoid AE contamination from the feed. The removal efficiencies of some 114 AE homologues were determined by the application of a specific and sensitive analytical method. The extent of the removal of AE ranged from 99.70% for C18 compounds to > 99.98% for C12-16. Relatively high-AOH concentrations were observed in the effluents from blank and test units. By building the concentration difference from the test minus the control unit, the AE in the CAS effluent originating from AE in the influent was determined. Thus, it could be shown that AOH represented only 19% of the total AE (EO0-18) in the CAS, while monitoring in 29 WWTP effluents (European, Canadian, and US) revealed in total a mean AOH fraction of 55% (5-82%) of the total AE (EO0-18). This shows that only a small fraction of AOH in WWTP effluents originates from AE entering the WWTP.     

Evaluation of isothiocyanates as potent inducers of carcinogen-detoxifying enzymes in the urinary bladder: critical nature of in vivo bioassay

Deficiency of carcinogen-detoxifying phase 2 enzymes, such as glutathione S-transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1), increases bladder cancer risk in humans. We report that several isothiocyanates (ITCs) that have not been previously examined, 1-methylbutyl ITC in particular, potently and preferentially induce both GST and NQO1 in the rat bladder. Comparison of 25 ITCs that are closely related in chemical structures showed that a 3-5-carbon aliphatic side chain with a methyl group attached to the alpha carbon was crucial for maximal inducer activity in the bladder. Surprisingly, cell-based bioassays failed to predict the phase 2 enzyme-inducing activity of the ITCs in the bladder. Furthermore, although ITCs are principally metabolized in vivo to dithiocarbamates (DTCs), which are believed to serve as the carriers of ITCs and are rapidly eliminated and concentrated in the urine, the total urinary levels of ITC plus DTC did not correlate with the degree of GST and NQO1 induction by the ITCs in the bladder of rats. Thus, several underappreciated ITCs are exceedingly potent inducers of GST and NQO1 in the rat bladder but were predicted neither by in vitro bioassays of phase 2 enzyme induction nor by their appearance or concentration in urine in vivo.     

Transplantation for type I diabetes: comparison of vascularized whole-organ pancreas with isolated pancreatic islets

OBJECTIVE: We sought to compare the efficacy, risks, and costs of whole-organ pancreas transplantation (WOP) with the costs of isolated islet transplantation (IIT) in the treatment of patients with type I diabetes mellitus. SUMMARY BACKGROUND DATA: A striking improvement has taken place in the results of IIT with regard to attaining normoglycemia and insulin independence of type I diabetic recipients. Theoretically, this minimally invasive therapy should replace WOP because its risks and expense should be less. To date, however, no systematic comparisons of these 2 options have been reported. METHODS: We conducted a retrospective analysis of a consecutive series of WOP and IIT performed at the University of Pennsylvania between September 2001 and February 2004. We compared a variety of parameters, including patient and graft survival, degree and duration of glucose homeostasis, procedural and immunosuppressive complications, and resources utilization. RESULTS: Both WOP and IIT proved highly successful at establishing insulin independence in type I diabetic patients. Whole-organ pancreas recipients experienced longer lengths of stay, more readmissions, and more complications, but they exhibited a more durable state of normoglycemia with greater insulin reserves. Achieving insulin independence by IIT proved surprisingly more expensive, despite shorter initial hospital and readmission stays. CONCLUSION: Despite recent improvement in the success of IIT, WOP provides a more reliable and durable restoration of normoglycemia. Although IIT was associated with less procedure-related morbidity and shorter hospital stays, we unexpectedly found IIT to be more costly than WOP. This was largely due to IIT requiring islets from multiple donors to gain insulin independence. Because donor pancreata that are unsuitable for WOP can often be used successfully for IIT, we suggest that as IIT evolves, it should continue to be evaluated as a complementary alternative to rather than as a replacement for the better-established method of WOP.     

Covariation in addictive behaviours: a study of addictive orientations using the Shorter PROMIS Questionnaire

Previous research has suggested that different addictive behaviours are linked, such that decreases in one may lead to compensatory increases in another, or even that one addiction may lead to another. Such views on "cross addiction" are encouraged by the prevailing tendency amongst researchers from very different theoretical backgrounds to view different addictions as serving a common function, such as mood alteration, or the "management of hedonic tone." Previous studies have suggested that different addictions may usefully be grouped according to how they covary. The present study, using factor and cluster analyses, confirms the importance of a division between "hedonistic" and "nurturant" addictions, but with the need for further subdivisions within those categories. Hedonism comprises a "drug use" factor and an "interpersonal dominance" factor. Nurturance comprises both "self-regarding" and "other-regarding" factors. Theoretically, the results suggest that different addictions illustrate contrasting techniques of interpersonal manipulation. Clinically, the results indicate the drawbacks of addressing addictive behaviours singly, and the potential importance of addictive orientations in treatment, and relapse prevention.     

Comparative effects of pH and Vision herbicide on two life stages of four anuran amphibian species

Vision, a glyphosate-based herbicide containing a 15% (weight:weight) polyethoxylated tallow amine surfactant blend, and the concurrent factor of pH were tested to determine their interactive effects on early life-stage anurans. Ninety-six-hour laboratory static renewal studies, using the embryonic and larval life stages (Gosner 25) of Rana clamitans, R. pipiens, Bufo americanus, and Xenopus laevis, were performed under a central composite rotatable design. Mortality and the prevalence of malformations were modeled using generalized linear models with a profile deviance approach for obtaining confidence intervals. There was a significant (p < 0.05) interaction of pH with Vision concentration in all eight models, such that the toxicity of Vision was amplified by elevated pH. The surfactant is the major toxic component of Vision and is hypothesized, in this study, to be the source of the pH interaction. Larvae of B. americanus and R. clamitans were 1.5 to 3.8 times more sensitive than their corresponding embryos, whereas X. laevis and R. pipiens larvae were 6.8 to 8.9 times more sensitive. At pH values above 7.5, the Vision concentrations expected to kill 50% of the test larvae in 96-h (96-h lethal concentration [LC50]) were predicted to be below the expected environmental concentration (EEC) as calculated by Canadian regulatory authorities. The EEC value represents a worst-case scenario for aerial Vision application and is calculated assuming an application of the maximum label rate (2.1 kg acid equivalents [a.e.]/ha) into a pond 15 cm in depth. The EEC of 1.4 mg a.e./L (4.5 mg/L Vision) was not exceeded by 96-h LC50 values for the embryo test. The larvae of the four species were comparable in sensitivity. Field studies should be completed using the more sensitive larval life stage to test for Vision toxicity at actual environmental concentrations.     

Chemical and biomonitoring to assess potential acute effects of Vision herbicide on native amphibian larvae in forest wetlands

In conjunction with operational forest herbicide spray programs in Ontario, Canada, chemical and biological monitoring studies were conducted in 51 different wetlands to quantify the probability and magnitude of contamination by a glyphosate herbicide formulation (Vision). Wetlands were classified as oversprayed, adjacent, or buffered in relation to the operational target spray blocks. Results show that vegetated buffers significantly mitigated against exposure and thus potential for acute effects. Aqueous concentrations of glyphosate in buffered wetlands were below analytical limits of quantitation (0.02 mg acid equivalent [a.e.]/L) in 14 of 16 cases, with mean concentration (0.03 +/- 0.02 mg a.e./L) significantly (p < 0.05) less than that of either adjacent (0.18 +/- 0.06 mg a.e./L) or oversprayed wetlands (0.33 +/- 0.11 mg a.e./L). Biomonitoring with caged amphibian larvae showed no significant differences among mean mortality (48 h) of either Rana pipiens (p = 0.194) or Rana clamitans larvae (p = 0.129) exposed in situ to Vision under these various wetland conditions. Percent mortality was not significantly (p = 0.05) correlated with exposure concentrations for either amphibian species tested. Results suggest that exposures typically occurring in forest wetlands are insufficient to induce significant acute mortality in native amphibian larvae.     

Failure to gain weight on long-term parenteral nutrition attributed to tri-iodothyronine thyrotoxicosis

We describe the case of a 49-y-old female patient on long-term parenteral nutrition after abdominal surgery who failed to gain weight despite nutritional provision in excess of theoretical requirements. On investigation, she was found to have a negative nitrogen balance (-5.9 g) and to have a tri-iodothyronine thyrotoxicosis but without many of the typical clinical features of hyperthyroidism. The patient also had mild hypercalcemia and hyperphosphatemia, which resolved fully after mobilization and treatment of the thyrotoxicosis. A derangement of the liver function tests was observed, which worsened progressively during parenteral nutrition but resolved promptly at its discontinuation. This case illustrates the importance of carrying out appropriate investigations including all thyroid function tests on patients who fail to gain weight on nutritional support.     

Noise exposure and hearing loss among sand and gravel miners

The objectives of this study were to describe workplace noise exposures, risk factors for hearing loss, and hearing levels among sand and gravel miners, and to determine whether full shift noise exposures resulted in changes in hearing thresholds from baseline values. Sand and gravel miners (n = 317) were interviewed regarding medical history, leisure-time and occupational noise exposure, other occupational exposures, and use of hearing protection. Audiometric tests were performed both before the work shift (following a 12-hour noise-free interval) and immediately following the work shift. Full shift noise dosimetry was conducted. Miners' noise exposures exceeded the Recommended Exposure Limit (REL) of the National Institute for Occupational Safety and Health (NIOSH) for 69% of workers, and exceeded the Mine Safety and Health Administration's action level for enrollment in a hearing conservation program for 41% of workers. Significantly higher noise exposures occurred among employees of small companies, among workers with a job classification of truck driver, among males, and among black workers. Hearing protection usage was low, with 48% of subjects reporting that they never used hearing protection. Hearing impairment, as defined by NIOSH, was present among 37% of 275 subjects with valid audiograms. Black male workers and white male workers had higher hearing thresholds than males from a comparison North Carolina population unexposed to industrial noise. Small but statistically significant changes in hearing thresholds occurred following full shift noise exposure among subjects who had good hearing sensitivity at baseline. In a logistic regression model, age and history of a past noisy job were significant predictors of hearing impairment. Overall, sand and gravel workers have excessive noise exposures and significant hearing loss, and demonstrate inadequate use of hearing protection. Well-designed hearing conservation programs, with reduction of noise exposure, are clearly needed.     

Visual function in low birthweight children

AIM: To determine the visual functions, at age 10-12 years, of a geographically based cohort of children of birth weight less than 1701 g. The results were compared to a group of children born at full term. METHODS: 572 low birthweight (LBW) "low birthweight cohort" children who had been examined in the neonatal period were invited for review at 10-12 years of age. 169 11 year old schoolchildren born at full term were also recruited, "school cohort." Visual acuity (at distance and near), contrast sensitivity, colour vision, and visual fields were measured. RESULTS: 293 of the original 572 participants consented to a further examination. Compared to the school cohort of children born at term the low birthweight cohort showed significantly lower near and distance acuities and contrast sensitivity (p<0.001 for all uniocular and binocular measures). Retinopathy of prematurity (ROP) was a very poor predictor of outcome and multivariate analysis did not identify any key neonatal factors as predictors of long term visual outcome. CONCLUSIONS: Low birthweight children have a small but statistically significant deficit in both visual acuity and contrast sensitivity. Low birth weight and ROP both impact on long term visual functions.     

Microcirculatory effects of melatonin in rat skeletal muscle after prolonged ischemia

The purpose of this study was to determine microcirculatory effects and response of nitric oxide synthase (NOS) to melatonin in skeletal muscle after prolonged ischemia. A vascular pedicle isolated rat cremaster muscle model was used. Each muscle underwent 4 hr of zero-flow warm ischemia followed by 2 hr of reperfusion. Melatonin (10 mg/kg) or saline as a vehicle was given by intraperitoneal injection at 30 min prior to reperfusion and the same dose was given immediately after reperfusion. After reperfusion, microcirculation measurements including arteriole diameter, capillary perfusion and endothelial-dependent and -independent vasodilatation were performed. The cremaster muscle was then harvested to measure endothelial NOS (eNOS) and inducible NOS (iNOS) gene expression and enzyme activity. Three groups of rats were used: sham-ischemia/reperfusion (I/R), vehicle + I/R and melatonin + I/R. As compared with vehicle + I/R group, administration of melatonin significantly enhanced arteriole diameter, improved capillary perfusion, and attenuated endothelial dysfunction in the microcirculation of skeletal muscle after 4 hr warm ischemia. Prolonged warm ischemia followed by reperfusion significantly depressed eNOS gene expression and constitutive NOS activity and enhanced iNOS gene expression. Administration of melatonin did not significantly alter NOS gene expression or activity in skeletal muscle after prolonged ischemia and reperfusion. Melatonin provided a significant microvascular protection from reperfusion injury in skeletal muscle. This protection is probably attributable to the free radical scavenging effect of melatonin, but not to its anti-inflammatory effect.