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The ineffective cleaning of surgical instruments may be a vector for the transmission of hospital-acquired infections. The aim of this research was to investigate whether further decontamination procedures need to be instigated in sterile-service departments (SSDs) to reduce the risk of nosocomial illnesses, such as endotoxemia, sepsis, or iatrogenic Creutzfeldt-Jakob disease (to date, 1,147 cases of confirmed Creutzfeldt-Jakob disease deaths in the United Kingdom since 1990 have been reported). Instrument sets were obtained from nine anonymous United Kingdom National Health Service (NHS) primary care trust SSDs. The investigation implemented an advanced light microscopy technique, episcopic differential interference contrast microscopy with the sensitive fluorescent reagents SYPRO Ruby and 4,6-diamidino-2-phenylindole dihydrochloride (DAPI), to detect proteinaceous and microbial contamination levels. Gram-negative lipopolysaccharide (LPS) endotoxin was monitored using a dansylated polymyxin B fluorochrome agent. None of the 260 instruments examined displayed signs of microbial colonization or LPS endotoxin contamination. However, over 60 percent of the instruments showed a high degree of protein soiling (0.4 to 4.2 g protein/mm2 ). Some instruments appeared soiled with crystalline deposits that may consist of a potentially hazardous material contributing to inflammation and/or surgical shock. It is clear that the overall standard for cleaning must be raised in order to fulfill the imminent introduction of new European standards and to reduce the risk of cross-patient contamination and iatrogenic transmission.

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Prolonged operation of piezoelectric ceramic devices under high dc electric fields promotes leakage currents between the electrodes. This paper investigates the effects of ceramic porosity, edge conduction and electrode materials and geometry in the development of low resistance conduction paths through the ceramic. Localized changes in the ceramic structure and corresponding microscopic breakdown sites are shown to be associated with leakage currents and breakdown processes resulting from prolonged operation in harsh environments. The role of barrier coatings in mitigating the effects of humidity is studied, and results are presented on improved performance using composite diamond-like carbon/polymer coatings. In contrast to the changes in the electrical properties of the ceramic, the measurements of the piezoelectric properties showed no significant effect of humidity.

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a group of rare, transmissible and fatal neurodegenerative diseases associated with the protein agent (PrP Sc ).As such, the sensitive and rapid detection of prion PrP Sc amyloid on the surface of suspect surgical instruments is of great importance and may even allow remedial action to be taken prior to any further operative intervention and possible iatrogenic transmission. However, conventional PrP Sc detection methodologies tend to rely on the inefficient and unreliable removal of suspect material from a surface using swabs or wipes prior to antibody analysis. Here we show how the combination of an advanced light microscope technique, episcopic differential interference contrast/epifluorescence (EDIC/EF) microscopy, and the application of b-amyloid fluorescent thiazole markers (thioflavin T, thioflavin S) can be used to detect, in situ, submicron (attomole) levels of prion protein amyloid contamination in brain and spleen sections, smears and homogenate on surgical stainless steel surfaces and surgical instruments. This technique, although not specific to an amyloid type, can be used to verify that surgical instruments are substantially free from prion amyloid protein soiling and hence reduce the risk of iatrogenic transmission. INTRODUCTIONIn 1996 a new addition to the group of rare and fatal human transmissible spongiform encephalopathies was identified . This addition was termed as variant Creutzfeldt-Jakob disease (vCJD), and has been linked with the consumption of bovine spongiform encephalopathy (BSE)-infected products in the late 1980s (SCENIHR, 2005). Although vCJD possesses similarities to sporadic CJD (sCJD), research has shown that certain organs outside the central nervous system can transmit the disease (ACDP/SEAC, 2003), a situation that has been considered to be minimal in spontaneous or idiopathic strains such as sCJD (Pauli, 2005). The incidence of vCJD deaths has decreased from a peak of 28 cases in 1998 to only 5 in 2005. The same number of cases also occurred in 2006 (UK CJD Surveillance Unit, 2006) and this plateau in incidences may give an indication that the disease will become endemic to the human population (Ironside, 2006).However, with the recent evidence emerging that peripheral tissues and blood are capable of transmitting the disease then it is clear that iatrogenic Creutzfeldt-Jakob disease (iCJD) is potentially a major health problem, especially with the possibility of relatively large numbers of subclinical asymptomatic carriers of the disease being present in the UK population. A 2004 study reported the prevalence of prion protein in an anonymized study of 12 674 suitable appendectomy samples obtained from histopathology departments across the UK (Hilton et al., 2004). This report indicated that they had identified 3 samples that displayed an accumulation of prion protein and this produced an extrapolated prevalence of 237 per million (95 % confidence interval 49-692 per million). Also, in 2004 it was repo...

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