Fungal colonization and biodeterioration of plasticized polyvinyl chloride

Significant substratum damage can occur when plasticized PVC (pPVC) is colonized by microorganisms. We investigated microbial colonization of pPVC in an in situ, longitudinal study. Pieces of pPVC containing the plasticizers dioctyl phthalate and dioctyl adipate (DOA) were exposed to the atmosphere for up to 2 years. Fungal and bacterial populations were quantified, and colonizing fungi were identified by rRNA gene sequencing and morphological characteristics. Aureobasidium pullulans was the principal colonizing fungus, establishing itself on the pPVC between 25 and 40 weeks of exposure. A group of yeasts and yeast-like fungi, including Rhodotorula aurantiaca and Kluyveromyces spp., established themselves on the pPVC much later (after 80 weeks of exposure). Numerically, these organisms dominated A. pullulans after 95 weeks, with a mean viable count +/- standard error of 1,000 +/- 200 yeast CFU cm(-2), compared to 390 +/- 50 A. pullulans CFU cm(-2). No bacterial colonization was observed. We also used in vitro tests to characterize the deteriogenic properties of fungi isolated from the pPVC. All strains of A. pullulans tested could grow with the intact pPVC formulation as the sole source of carbon, degrade the plasticizer DOA, produce extracellular esterase, and cause weight loss of the substratum during growth in vitro. In contrast, several yeast isolates could not grow on pPVC or degrade DOA. These results suggest that microbial succession may occur during the colonization of pPVC and that A. pullulans is critical to the establishment of a microbial community on pPVC.

Plasticizers increase adhesion of the deteriogenic fungus Aureobasidium pullulans to polyvinyl chloride

Initial adhesion of fungi to plasticized polyvinyl chloride (pPVC) may determine subsequent colonization and biodeterioration processes. The deteriogenic fungus Aureobasidium pullulans was used to investigate the physicochemical nature of adhesion to both unplasticized PVC (uPVC) and pPVC containing the plasticizers dioctyl phthalate (DOP) and dioctyl adipate (DOA). A quantitative adhesion assay using image analysis identified fundamental differences in the mechanism of adhesion of A. pullulans blastospores to these substrata. Adhesion to pPVC was greater than that to uPVC by a maximum of 280% after a 4-h incubation with 10(8) blastospores ml(-1). That plasticizers enhance adhesion to PVC was confirmed by incorporating a dispersion of both DOA and DOP into the blastospore suspension. Adhesion to uPVC was increased by up to 308% in the presence of the dispersed plasticizers. Hydrophobic interactions were found to dominate adhesion to uPVC because (i) a strong positive correlation was observed between substratum hydrophobicity (measured by using a dynamic contact angle analyzer) and adhesion to a range of unplasticized polymers including uPVC, and (ii) neither the pH nor the electrolyte concentration of the suspension buffer, both of which influence electrostatic interactions, affected adhesion to uPVC. In contrast, adhesion to pPVC is principally controlled by electrostatic interactions. Enhanced adhesion to pPVC occurred despite a relative reduction of 13 degrees in the water contact angle of pPVC compared to that of uPVC. Furthermore, adhesion to pPVC was strongly dependent on both the pH and electrolyte concentration of the suspension medium, reaching maximum levels at pH 8 and with an electrolyte concentration of 10 mM NaCl. Plasticization with DOP and DOA therefore increases adhesion of A. pullulans blastospores to pPVC through an interaction mediated by electrostatic forces.

An investigation of laser scanning techniques for quantifying changes in facial soft-tissue volume

This paper describes a laser scanning technique to measure accurately changes in facial volume. Three potential sources of error were identified: the registration algorithm, the inherent accuracy of the scanner, and the natural minute-to-minute variability of the human face. In experiments performed to discover the relative magnitude and significance of each source of error, the performance of the registration algorithm was found to be limited by the accuracy of the data, being 1.6 cc, on average, measured over the entire face of a plaster model. Scan-to-scan variability in the shape of the human face was measured at 3.3 cc on average. We conclude that laser scanning is a simple, non-invasive, accurate, and reproducible means of assessing changes in facial volume.

Expanding the nursing repertoire: the effect of massage on post-operative pain

An equivalent groups design with a treatment group of 19 patients and a control group of 20 patients was used to investigate the impact of massage therapy on patients' perceptions of post-operative pain. Data were analysed using analysis of covariance repeated measures (within subjects) design. Controlling for age, the results indicated that massage produced a significant reduction in patients' perceptions of pain over a 24 hour period. A linear positive relationship emerged between patients' age and the duration of the massage. The study indicates that further investigation of the potential for massage to reduce pain is warranted.

Effect of treatment of hyperthyroidism on renal function in cats

OBJECTIVE

To determine whether increases in BUN and serum creatinine (SCr) concentrations, which have been reported to develop after surgical bilateral thyroidectomy in hyperthyroid cats, also develop after treatment of hyperthyroidism with radioactive iodine and methimazole.

DESIGN

Prospective, clinical trial.

ANIMALS

58 hyperthyroid cats.

PROCEDURE

Urine specific gravity, SCr, BUN, and serum thyroxine (T4) concentrations were determined before and 30 and 90 days after treatment of hyperthyroidism with radioactive iodine, methimazole, or surgical bilateral thyroidectomy.

RESULTS

Mean SCr and BUN concentrations determined 30 and 90 days after treatment were significantly higher than those measured before treatment. Mean SCr, BUN, and T4 concentrations were not different among groups before treatment or 30 and 90 days after treatment.

CLINICAL IMPLICATIONS

Reduction of serum T4 concentrations after treatment of hyperthyroidism may result in azotemia in older cats with chronic renal disease. Treating azotemic hyperthyroid cats with methimazole until it can be determined whether correction of the hyperthyroid state will exacerbate the azotemia may be prudent.

A prospective study of isolation of Moraxella catarrhalis in a hospital during the winter months

Sputum samples submitted to the microbiology laboratory from general medical and respiratory wards were monitored for Moraxella catarrhalis on a prospective basis. All isolates were typed by restriction endonuclease typing. Nosocomial spread was found both by the clustering of cases and typing of isolates. Sampling of the environment of some cases was performed. Seven out of 37 samples revealed environmental contamination. Sampling for persistence of the organism in the environment was positive on one occasion out of 13. Evaluation of acquisition of M. catarrhalis in relation to length of stay showed that the average length of stay of a case with M. catarrhalis was considerably longer than average patient stay without M. catarrhalis. Four patients had two isolates available for typing. The type of M. catarrhalis was different on the second occasion to that on the first. Nosocomial spread of M. catarrhalis in the setting of general medical and respiratory wards was found to occur in the winter months.

A case of pseudoanaphylactic reaction to intramuscular procaine penicillin G (Hoigne's syndrome)

A personal record of a pseudoanaphylactic reaction to procaine penicillin G is presented, together with a brief discussion of the topic. Since procaine penicillin is widely used in Papua New Guinea the reaction may be more common than is generally realized. The reaction is not a true anaphylaxis and is probably caused by the procaine component after inadvertent intravenous injection of the drug.

Anxiety and unrealistic optimism

Substantial evidence suggest that people tend to be unrealistically optimistic that positive events will happen to them and that negative events will not. However, recent research indicates that under certain conditions they may be unrealistically pessimistic. Variations in the levels of optimism and pessimism experienced towards events are generally given cognitive explanations. A relation between optimism and pessimism and anxiety, a variable related to emotion as well as cognition, was investigated in the present study. An inverse correlation was found between how anxious female students in England felt about certain negative events and how unrealistically optimistic they were about the occurrence of those events. It was concluded that the degree of anxiety experienced toward a negative event may affect the level of unrealistic optimism or pessimism toward it.

Geriatric rehabilitation: a family practice approach

Geriatric patients require rehabilitative measures that restore function and prevent further loss, with the goal of preserving independence. Assessment of functional ability and problems contributing to the disability (there are frequently more than one in elderly patients) help to make realistic goals for treatment. Functional scales provide rational evaluation of baseline status, progress made during treatment, and when remission has occurred.

Magnesium chloride as an anaesthetic for cephalopods

Magnesium chloride is an effective anaesthetic and narcotizing agent for cephalopod molluscs. Individuals belonging to five genera (decapod and octopod) were anaesthetized and subsequently revived at temperatures ranging from 13 to 22 degrees C. At no stage of anaesthesia does MgCl2 appear to cause any trauma. There is evidence that MgCl2 acts centrally on the nervous system to induce anaesthesia. This salt, cheap, readily available and convenient to use, is recommended over urethane or ethanol as a suitable anaesthetic or narcotic for use with cephalopods.

Magnesium chloride as an anaesthetic for cephalopods

Magnesium chloride is an effective anaesthetic and narcotizing agent for cephalopod molluscs. Individuals belonging to five genera (decapod and octopod) were anaesthetized and subsequently revived at temperatures ranging from 13 to 22 degrees C. At no stage of anaesthesia does MgCl2 appear to cause any trauma. There is evidence that MgCl2 acts centrally on the nervous system to induce anaesthesia. This salt, cheap, readily available and convenient to use, is recommended over urethane or ethanol as a suitable anaesthetic or narcotic for use with cephalopods.