Efficacy of novel aqueous photo-chlorine dioxide against a human norovirus surrogate, bacteriophage MS2 and Clostridium difficile endospores, in suspension, on stainless steel and under greenhouse conditions.

AIMS: The efficacy of a novel photochemical method for generating chlorine dioxide (photoClO2 ) was evaluated against human noroviruses (HuNoV) surrogate, bacteriophage MS2, and Clostridium difficile endospores. METHODS AND RESULTS: Chlorine dioxide was generated by mixing 1% sodium chlorite with 10 parts-per-million (ppm) Eosin Y and irradiating with a photo-activator-excitable light. PhotoClO2 efficacy was assessed against bacteriophage MS2 and C. difficile endospores in suspension, on hard surfaces and greenhouse conditions under soiled and unsoiled conditions. The estimated effective photoClO2 produced and consumed was 20·39 ± 0·16 ppm at a rate of 8·16 ppm per min in a 1% sodium chlorite solution. In suspension, MS2 phage was reduced by 3·35 and >5·10 log10 PFU per ml in 120 and 90 min, with and without soil, respectively. At the same time, when dried on stainless steel surface, MS2 phage was reduced by >4·53 log10 PFU per carrier in 30 min under both conditions. On the other hand, C. difficile endospores in suspension were reduced by 2·26 and 3·65 log10 CFU per ml in 120 min with and without soiling, respectively. However, on stainless steel surface, maximal reductions of the C. difficile endospores were 0·8 and 1·5 log10 CFU per carrier with and without soiling, respectively, and a maximal reduction of 2·97 log10 CFU per carrier under greenhouse conditions at 24 h. CONCLUSIONS: Overall, photoClO2 showed promise as a technology to control HuNoV contamination on environmental surfaces but requires further optimization and testing against C. difficile endospores. SIGNIFICANCE AND IMPACT OF THE STUDY: Results from this investigation will serve as a model for how to generate and quantify photoClO2 and how to appropriately evaluate this new class of disinfectants against environmentally resilient pathogens: viruses and bacterial endospores.

Recurrent ascites and pleural effusions after surgery for early-stage endometrial adenocarcinoma.

A case of massive postoperative ascites in a woman treated for endometrial cancer is reported. A workup for typical causes of ascites yielded negative results, prompting a more detailed analysis of the patient's condition. Hypothyroidism was discovered. After correction of the hypothyroidism, the ascites slowly resolved. Since myxedema is an uncommon cause of ascites, this is usually a diagnosis of exclusion. However, hypothyroidism must be ruled out to prevent unnecessary and possibly inappropriate treatments for ascites.

Volumetric umbilical artery blood flow: comparison of the normal versus the single umbilical artery cord.

OBJECTIVE: This was a study of the volumetric blood flow in single umbilical artery (SUA) cords as compared to three-vessel cords. HYPOTHESIS: SUA flow will be twice that of an artery in a normal cord. METHODS: We studied 276 patients (24 SUA, 252 normal cord) at 18-40 weeks' gestation utilizing gray-scale and color Doppler. Flow, flow/kg, velocity, artery diameter, Doppler velocimetry indices, estimated fetal weight (EFW) and amniotic fluid index (AFI) were compared. All fetuses were anatomically and cytogenetically normal. RESULTS: Blood flow increased with advancing gestation and the SUA volume was twice that in the normal cord artery. Flow/kg decreased for both cords, with the SUA values twice those of normal cords. Arterial diameter and velocity increased, but to a greater degree in SUA. Velocimetry, although in the normal range, decreased progressively with the resistance indices always lower in the SUA cord. EFW and AFI were the same for both groups. CONCLUSION: Volumetric blood and its components were measured indirectly with ultrasound. The SUA cord artery carried twice the blood volume of an artery in a three-vessel cord. Other flow parameters changed appropriately to explain the increased flow. For the anatomically normal fetus with SUA there was no increase in intrauterine growth restriction.

Comparison of chlorine and a prototype produce wash product for effectiveness in killing Salmonella and Escherichia coli O157:H7 on alfalfa seeds.

Outbreaks of Salmonella and Escherichia coli O157:H7 infections associated with alfalfa and other seed sprouts have occurred with increased frequency in recent years. This study was undertaken to determine the efficacy of a liquid prototype produce wash product (Fit), compared with water and chlorinated water, in killing Salmonella and E. coli O157:H7 inoculated onto alfalfa seeds. We investigated the efficacy of treatments as influenced by seeds from two different lots obtained from two seeds suppliers and by two methods of inoculation. The efficacy of treatments was influenced by differences in seed lots and amount of organic material in the inoculum. Significant (alpha = 0.05) reductions in Salmonella populations on seeds treated with 20,000 ppm of chlorine or Fit for 30 min ranged from 2.3 to 2.5 log10 CFU/g and 1.7 to 2.3 log10 CFU/g, respectively. Reductions (alpha = 0.05) in E. coli O157:H7 ranged from 2.0 to 2.1 log10 CFU/g and 1.7 to more than 5.4 log10 CFU/g of seeds treated, respectively, with 20,000 ppm of chlorine or Fit. Compared with treatment with 200 ppm of chlorine, treatment with either 20,000 ppm of chlorine or Fit resulted in significantly higher reductions in populations of Salmonella and E. coli O157:H7. None of the treatments eliminated these pathogens as evidenced by their detection on enrichment of treated seeds. Considering the human health and environmental hazards associated with the use of 20,000 ppm of chlorine, Fit provides an effective alternative to chlorine as a treatment to significantly reduce bacterial pathogens that have been associated with alfalfa seeds.

Occupational tuberculosis among deputy sheriffs in Connecticut: a risk model of transmission.

OBJECTIVES: The purpose of this study was to identify risk factors for tuberculin skin test conversions among non-infected deputy sheriffs in Connecticut and during an out-break in an urban lock-up. METHODS: 377 tuberculin skin-test negative sheriffs statewide in 1994-1995 and 37 sheriffs in the lock-up in 1995 were screened and questionnaires administered. Cellblock volumetric air flow was measured. The Wells-Riley model of airborne transmission [C = S(1-e-Iqpt/Q)] was applied to the epidemiologic and ventilation data. RESULTS: Statewide, of 377 sheriffs screened, 22 (5.8%) had positive skin tests. Risk factors included older age (p < .0075) and longer tenure (p < .036). In the lock-up, of 37 sheriffs screened, 4 (10.8%) had positive skin tests. Measured mean outside air flow per occupant (8.0 cfm; S.D. = 2.2) was below design (15 cfm) and recommended (20 cfm) standards. Mathematical modeling estimated that TB transmission would be reduced by 62.5 percent with ventilation at design specifications. CONCLUSIONS: Inadequate ventilation may increase the risk for occupational transmission of tuberculosis. Since lock-ups do not have the time to conduct inmate TB screenings, supplemental engineering controls may be required.

Effects of DNA polymer length on its adsorption to soils.

Three different DNA fragments ranging size from 2.69 kbp (1.75 MDa) to 23 kbp (14.95 MDa) were used as tracers to study the adsorption of polydisperse solutions of calf thymus DNA to eight model soils. The adsorption of the three tracers to all soils was described by the Freundlich adsorption model, with adsorption coefficients (K) ranging from 1.1 for acid-washed sand to over 300 for one soil. An inverse relationship between tracer size and K was observed with six of the eight soils, indicating that smaller fragments are sorbed preferentially versus larger fragments in these soils. No significant correlation between K and the organic carbon contents, clay contents, pHs, or cation exchange capacities of the model soils was observed.

Biodegradation of mixtures of substituted benzenes by Pseudomonas sp. strain JS150.

Pseudomonas sp. strain JS150 was isolated as a nonencapsulated variant of Pseudomonas sp. strain JS1 that contains the genes for the degradative pathways of a wide range of substituted aromatic compounds. Pseudomonas sp. strain JS150 grew on phenol, ethylbenzene, toluene, benzene, naphthalene, benzoate, p-hydroxybenzoate, salicylate, chlorobenzene, and several 1,4-dihalogenated benzenes. We designed experiments to determine the conditions required for induction of the individual pathways and to determine whether multiple substrates could be biodegraded simultaneously. Oxygen consumption studies with whole cells and enzyme assays with cell extracts showed that the enzymes of the meta, ortho, and modified ortho cleavage pathways can be induced in strain JS150. Strain JS150 contains a nonspecific toluene dioxygenase with a substrate range similar to that found in strains of Pseudomonas putida. The presence of the dioxygenase along with multiple pathways for metabolism of substituted catechols allows facile extension of the growth range by spontaneous mutation and degradation of mixtures of substituted benzenes and phenols. Chlorobenzene-grown cells of strain JS150 degraded mixtures of chlorobenzene, benzene, toluene, naphthalene, trichloroethylene, and 1,2- and 1,4-dichlorobenzenes in continuous culture. Under similar conditions, phenol-grown cells degraded a mixture of phenol, 2-chloro-, 3-chloro, and 2,5-dichlorophenol and 2-methyl- and 3-methylphenol. These results indicate that induction of appropriate biodegradative pathways in strain JS150 permits the biodegradation of complex mixtures of aromatic compounds.

Simultaneous biodegradation of chlorobenzene and toluene by a Pseudomonas strain.

Pseudomonas sp. strain JS6 grows on a wide range of chloro- and methylaromatic substrates. The simultaneous degradation of these compounds is prevented in most previously studied isolates because the catabolic pathways are incompatible. The purpose of this study was to determine whether strain JS6 could degrade mixtures of chloro- and methyl-substituted aromatic compounds. Strain JS6 was maintained in a chemostat on a minimal medium with toluene or chlorobenzene as the sole carbon source, supplied via a syringe pump. Strain JS6 contained an active catechol 2,3-dioxygenase when grown in the presence of chloroaromatic compounds; however, in cell extracts, this enzyme was strongly inhibited by 3-chlorocatechol. When cells grown to steady state on toluene were exposed to 50% toluene-50% chlorobenzene, 3-chlorocatechol and 3-methylcatechol accumulated in the medium and the cell density decreased. After 3 h, the enzyme activities of the modified ortho ring fission pathway were induced, the metabolites disappeared, and the cell density returned to previous levels. In cell extracts, 3-methylcatechol was degraded by both catechol 1,2- and catechol 2,3-dioxygenase. Strain JS62, a catechol 2,3-dioxygenase mutant of JS6, grew on toluene, and ring cleavage of 3-methylcatechol was catalyzed by catechol 1,2-dioxygenase. The transient metabolite 2-methyllactone was identified in chlorobenzene-grown JS6 cultures exposed to toluene. These results indicate that strain JS6 can degrade mixtures of chloro- and methylaromatic compounds by means of a modified ortho ring fission pathway.

Chlorinated biphenyl mineralization by individual populations and consortia of freshwater bacteria.

Comparative studies were performed to investigate the contribution of microbial consortia, individual microbial populations, and specific plasmids to chlorinated biphenyl biodegradation among microbial communities from a polychlorinated biphenyl-contaminated freshwater environment. A bacterial consortium, designated LPS10, was shown to mineralize 4-chlorobiphenyl (4CB) and dehalogenate 4,4'-dichlorobiphenyl. The LPS10 consortium involved three isolates: Pseudomonas testosteroni (LPS10A), which mediated the breakdown of 4CB and 4,4'-dichlorobiphenyl to 4-chlorobenzoic acid; an isolate tentatively identified as an Arthrobacter sp. (LPS10B), which mediated 4-chlorobenzoic acid degradation; and Pseudomonas putida bv. A (LPS10C), whose role in the consortium has not been determined. None of these isolates contained detectable plasmids or sequences homologous to the 4CB-degradative plasmid pSS50. A freshwater isolate, designated LBS1C1, was found to harbor a 41-megadalton plasmid that was related to the 35-megadalton plasmid pSS50, and this isolate was shown to mineralize 4CB. In chemostat enrichments with biphenyl and 4CB as primary carbon sources, the LPS10 consortium was found to outcomplete bacterial populations harboring plasmids homologous to pSS50. These results demonstrate that an understanding of the biodegradative capacity of individual bacterial populations as well as interacting populations of bacteria must be considered in order to gain a better understanding of polychlorinated biphenyl biodegradation in the environment.

The effect of nicardipine on neuronal function following ischemia.

In cerebral ischemia, it has been proposed that calcium influx into neurons results in irreversible cellular injury during reperfusion. We administered nicardipine, a dihydropyridine calcium entry blocker, by continuous subcutaneous infusion to twenty five rats beginning before (PR) or following (PO) ischemia, and compared somatosensory evoked potentials (SEPs) to twenty eight ischemic control animals. Comparable ischemic cellular changes were seen in the hippocampi of all animals. SEP amplitude was higher in both the PR (p less than .005) and PO (p less than .0005) groups compared to controls. This effect was found in all three components (P1, N1, P2) of the evoked response. Plasma nicardipine levels of 6-10 ng/ml were associated with mild hypotension. We conclude that nicardipine improved neuronal function as measured by SEPs when administered before or after ischemia, most likely by interrupting the cytotoxic events occurring in cortical neurons during reperfusion.

Simulation of psychosis on a multiple-choice projective test.

The ability of a new multiple-choice group Rorschach instrument to differentiate 62 undergraduate students asked to simulate psychosis from 75 students and 55 schizophrenics given standard instructions was investigated. For each of 50 responses to miniature inkblots, normals and psychotics chose one of four alternative answers as most descriptive of what the stimulus looked like. Simulators responded as they thought a psychotic or insane person would. As hypothesized, simulators chose significantly more "good form but bizarre wording" responses than normals or psychotics, suggesting that the test is promising as a practical clinical indicator of attempts to simulate psychosis.

Death anxiety: "state" or "trait"?

Investigated relative effects of hypnosis, alpha biofeedback, prestige suggestion, and silence in attenuating experimentally induced increases in death anxiety. Forty female undergraduate Ss at Louisiana State University were tested on four measures of death anxiety: "Emotional" associations to "death" words, association response latencies to "death" vs. "neutral" words, Death Anxiety Scale, and Death Concern Scale. Ss then were assigned to four treatments: (1) Hypnosis, with anxiolytic post-hypnotic relaxation suggestions; (2) Nonhypnotic anxiolytic prestige suggestions; (3) EEG alphacontingent biofeedback; and (4) a 15-minute waiting period. After treatments, Ss viewed a tape-slide presentation that emphasized personal death and overestimated its probability from various causes. Ss then were retested on death anxiety measures, forms of which were counterbalanced within groups. Analysis of variance (at .05 and .01 confidence levels) failed to differentiate groups on either increases or decreases of death anxiety. It was concluded that death anxiety may be a "trait" as opposed to a "state" phenomenon.