Biomedical subjects
K Vickery
Publications and source records attributed to K Vickery.
Bankrupt chains regrouping as climate improves.
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Evaluation of the effectiveness of decontamination of dental syringes.
AIM: Steam autoclaving is the gold standard for decontaminating dental instruments, but worldwide disinfection is still widely employed. We have evaluated a range of procedures for their ability to inactivate duck hepatitis B virus contaminating dental syringes. METHODS: Residual infectivity of virus suspensions following 2% glutaraldehyde treatment, ultrasonication or steam sterilisation at 121 degrees or 134 degrees was assayed by injecting day-old ducklings and examining their livers for viral DNA 2.5 weeks later. Dental syringes were contaminated with DHBV positive blood, then treated by the same methods. An anaesthetic cartridge containing water was loaded into the syringe and 400microl aliquots used to inject day-old ducklings. Used dental syringes were examined by Scanning Electron Microscopy. RESULTS: Suspension test:- ultrasonic treatment failed to inactivate DHBV in suspension, but complete inactivation was achieved by 2% glutaraldehyde and autoclaving. Syringe test:- neither ultrasonic treatment nor glutaraldehyde inactivated DHBV. Autoclaving at 134 degrees (3 minutes) permitted transmission to 1/16 ducklings but steam sterilisation at 121 degrees (15 minutes) was effective. Electronmicroscopy demonstrated organic debris (biofilm) in the lumen of used syringes. CONCLUSION: Short autoclaving cycles, albeit at raised temperatures, may fail to inactivate the virus because of poor steam penetration, inadequate heat transfer and the accumulation of protective biofilm.
The preparation, characterisation, and DNA adduct profile of 2-amino-2-methyl-3-butanoneoximedichloroplatinum(II), a platinum(II) complex designed to bind to GpA sequences of DNA.
The complex, 2-amino-2-methyl-3-butanoneoximedichloroplatinum(II), [Pt(ambo)Cl2], was chosen because of its potential to bind to GpA sequences of duplex DNA. Crystals of [Pt(ambo)Cl2] are monoclinic, space group, P2(1)/n, a = 6.799(4), b = 17.642(5), c = 8.193(2) A, beta = 102.10(3) degrees, Z = 4, R = 0.033 (1864 F). The binding of [Pt(ambo)Cl2] to salmon-sperm DNA was studied using enzymatic digestion and HPLC analysis. [Pt(ambo)Cl2] was found to form fewer GpG and ApG intrastrand adducts and more monofunctional adducts than [Pt(en)Cl2]. Binding to GpA sequences could not be established, but [Pt(ambo)Cl2] forms substantially more adducts with adenine than does [Pt(en)Cl2].
Genesis Health Ventures restructures multicare acquisition.
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New Mexico to set new staffing levels for nursing facilities.
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Baltimore facilities battle over 'whites only' bequest.
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Rebuilding through bankruptcy.
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Long-term care on auction block. The key question is, who will own the companies?
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Going with the flow. Providers expand service to create a smooth continuum of care.
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Corruption in Oklahoma. FBI probe uncovers criminal activity in nursing facility inspection process.
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Comparison of the kinetics of the specific cellular immune response to duck hepatitis B virus in infected and immune ducks.
The kinetics of the cell mediated immune response by ducks acutely and chronically infected with, or immune to infection by duck hepatitis B virus (DHBV) was determined. This was measured by an antigen specific blastogenesis assay to duck hepatitis B surface antigen (DHBsAg) and duck hepatitis B core antigen (DHBcAg) using peripheral blood mononuclear cells (PBMC). The three outcomes of acute infection by DHBV were either clearance from both serum and liver, clearance from serum but not liver, or the development of persistent viraemia. Acutely infected ducks that failed to clear the infection also failed to develop a significant cellular immune response to both antigens. Ducks with chronic infection acquired as neonates or as the result of the failure to clear acute infection had an increasing cellular immune response over time. Two groups of immune ducks were examined. These were either ducks that had become immune following infection or that had been vaccinated. Both groups of ducks demonstrated significant cellular responses following challenge with DHBV irrespective of the level of their responses before challenge. However, there was a reduction in the response of their PBMC over a 4-week-period postchallenge. The range of cellular immune responses to DHBV antigens observed in this study has a number of counterparts in hepatitis B infection of humans. Coupled with the defined clinical outcomes that can be established in the duck/DHBV model, further study of the cellular immune response to DHBV is warranted.
Evaluation of disinfection and sterilization of reusable angioscopes with the duck hepatitis B model.
PURPOSE: Nosocomial transmission of viral hepatitis and retrovirus infection has been reported. The expected risk is greatest for the hepatitis B virus (HBV). The duck HBV (DHBV) has similar biologic and structural characteristics to HBV and has been adopted as a suitable model for disinfectant testing. METHODS: Angioscopic examination of the external jugular vein was performed on DHBV-infected ducks. After use, the instrument was air dried for 3 minutes. Samples were obtained by flushing the channel with 5 mL of phosphate buffered saline solution. The samples were collected immediately after drying (control), after flushing with 5 mL of water, after glutaraldehyde disinfection for 5, 10, and 20 minutes, and after ethylene oxide gas sterilization. Angioscopes were either precleaned or uncleaned before disinfection/sterilization. Residual infectivity was assessed with inoculation of samples into the peritoneal cavity of day-old ducks (n = 231). RESULTS: DNA analysis results of liver samples showed that all 38 control ducks became infected. The frequency of DHBV infection was reduced to 93% (14 of 15) by flushing the angioscope with 5 mL of sterile water. No transmission occurred after the use of any of the properly precleaned and disinfected/sterilized angioscopes. However, after the use of the uncleaned angioscopes, the transmission rate was 90% (9 of 10) and 70% (7 of 10) after 5 and 10 minutes of contact time, respectively, in 2% glutaraldehyde. Even after the recommended 20 minutes of contact time, there was still 6% (2 of 35) transmission. After ethylene oxide sterilization, two of the recipient ducklings (2 of 35) were infected with DHBV. CONCLUSION: There was no disease transmission after reuse of disposable angioscopes adequately cleaned before disinfection or sterilization. However, if the angioscopes are inadequately cleaned, DHBV can survive despite glutaraldehyde disinfection or ethylene oxide sterilization. This contrasts with previous in vitro and in vivo data with solid surgical instruments. It is postulated that the presence of a narrow lumen or residual protein shielding within the lumen may compromise effective inactivation of hepadnaviruses on angioscopes, with the potential risk for patient-to-patient transmission.
Inactivation of duck hepatitis B virus by a hydrogen peroxide gas plasma sterilization system: laboratory and 'in use' testing.
Human hepatitis B virus (HBV) is an important cause of nosocomial infections and can be transmitted by contaminated instruments. However, tests of the efficacy of sterilization of materials and equipment contaminated by HBV are difficult to perform because the virus cannot be cultured in the laboratory. In this study, we aimed to evaluate the capability of a low temperature, hydrogen peroxide gas plasma sterilizer (Sterrad, Advanced Sterilization Products, Irvine California,) to inactivate duck hepatitis B virus (DHBV). In laboratory efficacy studies using DHBV dried on to glass filter carriers and exposed to one-half of the hydrogen peroxide gas plasma sterilization process, there was a 10(7) or greater decrease in the viral titer, with no infectivity detected on the carriers after treatment. In-use studies were performed using a laparoscope that was experimentally contaminated with DHBV to mimic the possible transmission of infection between successive patients. Following exposure to the hydrogen peroxide gas plasma sterilization process no transmission of DHBV infection from the laparoscope occurred despite obvious visual soiling with blood (N = 8) while the transmission rate for the unprocessed laparoscope (positive control) was 100% (26/26), and that for instruments after a water wash was 63% (7/11). In conclusion the hydrogen gas plasma sterilization process completely inactivates DHBV a representative of the hepadna group of viruses.
DNA binding of lambda- and delta-cis-beta-[Ru(RR-picchxn)(phen)](2)+ studied by NMR and flow linear dichroism spectroscopy.
Two novel substitutionally-inert diastereomeric ruthenium(II) cations of the form lambda- and delta-cis-beta-[Ru(RR-picchxn)(phen)]2+, where RR-picchxn is N,N'-dimethyl-N,N'-di(2-picolyl)-1R,2R-diaminocyclohexane and phen is 1,10-phenanthroline, have been studied with respect to their interactions with duplex DNA. NMR investigations show that both diastereomers bind to the oligonucleotide [d(CGCGATCGCG)]2 in the fast exchange regime and that binding predominantly takes place in the minor groove of the oligonucleotide, but that the governing interactions are significantly different for the two delta and lambda forms. Linear dichroism data support the latter interpretation, in that the relative orientations of cis-beta-[Ru(RR-picchxn)(phen)]2+ to calf thymus DNA also are observed to differ for the delta and lambda diastereomers. Interpretation of these data indicates the lambda form to be bound with the planar phen ligand closely parallel to the DNA base-pairs, but the average orientation of the phen ligand in the delta form deviates significantly from a parallel alignment.
Seroprevalence of markers for hepatitis B, C and G in male and female prisoners--NSW, 1996.
OBJECTIVES: 1. Establish the prevalence of markers for hepatitis B (HBV), C (HCV) and G (HGV) in a sample of male and female inmates. 2. Examine exposure to multiple viruses. 3. Compare risk factors for HGV infection with known risk factors for HBV and HCV. DESIGN: Cross-sectional random sample stratified by sex, age and Aboriginality. Inmates were screened for three hepatitis markers. Participants were 789 inmates (657 male, 132 female) in 27 correctional centres in New South Wales, 1996. RESULTS: Overall detection of each of the three screening markers was 35% for HBV, 39% for HCV and 10% for HGV. Exposure rates were higher in female prisoners than males. Increased rates of anti-HBc were observed in Aboriginal inmates compared with non-Aboriginals (54% cf. 27%); anti-HCV and HGV-RNA were comparable between the two groups (36% cf. 41% and 9% cf. 10%). Markers were significantly higher in female injecting drug users (IDU), particularly HCV (90% cf. 66%). Thirty-five per cent of inmates were unaware of their HCV status. For HBV, 72% did not self-report past or present exposure despite serological evidence to the contrary. The multivariate analysis identified Aboriginality, long-term injecting and injecting while in prison as risk factors for HBV. HCV risk factors were female sex, non-Aboriginality, institutionalisation and IDU-associated behaviours. For HGV, female sex and previous imprisonment were significant risk factors but IDU was not. CONCLUSIONS: Blood-borne hepatitis viruses are common in prison inmates, particularly females (HBV, HCV and HGV), Aboriginals (HBV) and IDU (HBV and HCV). Infection can be related to a number of risk factors, which appear similar for HBV and HCV, but distinct from HGV.