Yvonne E. Cossart

Detection of subclinical infection in significant breast implant capsules

&NA; The pathogenesis of fibrous capsular contracture after augmentation mammaplasty is still debated. One hypothesis implicates low‐grade bacterial infections as a cause. The presence of a staphylococcal biofilm in a patient with recurrent capsular contracture was previously reported. A comparative, prospective, blinded, clinical study of implants and capsules removed from patients with or without significant capsular contracture was conducted to investigate the association of biofilm contamination, breast implants, and capsular contracture. Capsule and implant samples obtained during explantation were tested by routine microbiological culture, sensitive broth culture (after maceration and sonication), and scanning electron microscopy. Clinical parameters were correlated with microbiological findings. A total of 48 implant and/or capsule samples were obtained from 27 breasts during a 22‐month period. Of the 27 breasts, 19 exhibited significant contracture (Baker grade III/IV). The mean duration of implantation was 9.2 years (range, 0.4 to 26.0 years). Routine swab cultures obtained at the time of explantation were negative for bacterial growth for all samples. The sensitive broth culture technique yielded 24 positive samples (50 percent, n = 48). An analysis of capsules demonstrated that 17 of 19 samples obtained from patients with significant contracture were positive, compared with only one of eight samples obtained from patients with minimal or no contracture (p = 0.0006). Fourteen of the 17 positive cultures from significantly contracted breasts yielded coagulase‐negative staphylococci, mainly, species of the Staphylococcus epidermidis group. The presence of coagulase‐negative staphylococci was also significantly associated with capsular contracture (p = 0.01). There was no significant difference in the frequency of culture positivity for saline versus silicone implants (p = 0.885). Scanning electron microscopy confirmed the presence of extensive biofilm on implants and within capsules. Biofilm, in particular, S. epidermidis biofilm, was detected for a significant proportion of patients with capsular contracture. This implicates biofilm disease in the pathogenesis of contracture, and strategies for its prevention should be explored. (Plast. Reconstr. Surg. 111: 1605, 2003.)

Human papillomavirus positivity predicts favourable outcome for squamous carcinoma of the tonsil

Mutations in the p53 and retinoblastoma (pRb) pathways associated with the use of tobacco and alcohol are common in squamous cell carcinoma (SCC) of the head and neck. Cell cycle proteins are also affected by human papillomavirus (HPV), which may also have an aetiological role in cancers at particular sites, most notably the tonsil. Attempts to identify prognostic molecular markers in head and neck cancers have met with conflicting results, but few studies have been undertaken with tumours of known HPV status at a single anatomic site. In our study 86 tonsil cancers were analysed for HPV status by sequence analysis of polymerase chain reaction products and for the expression of cell cycle proteins (p53, p21CIP1/WAF1, pRb, p16INK4A, cyclin D1 and p27KIP1) by immunohistochemistry. The HPV status could be established in 67 of the tumours. Thirty‐one (46%) of these were HPV‐positive, predominantly (28/31) for HPV16. Findings were related to tumour recurrence and patient survival. None of the cell cycle proteins independently predicted recurrence or survival. Patients with HPV‐positive tumours, however, were significantly less likely (p < 0.05) to have recurrence or to die of disease than those with HPV‐negative tumours, after adjusting for the effects of the cell cycle proteins, clinical stage, pathological node status, tumour grade, age, gender and treatment. These findings support the concept that HPV‐positive tonsil cancers may be a distinct biological group with less aggressive characteristics. Screening of tonsil cancers for HPV DNA may help optimise treatment and provide more accurate prognostic information.

The Expression Of Key Cell Cycle Markers And Presence Of Human Papillomavirus In Squamous Cell Carcinoma Of The Tonsil.

Chemical carcinogens induce squamous cell carcinoma (SCC) of the head and neck by targeting the p53 and the retinoblastoma (pRb) pathways. Human papillomavirus (HPV) might have an etiologic role in these cancers at particular sites. Few studies have compared cell cycle protein expression in HPV‐positive and HPV‐negative tumors in this region.

Detection of persistent vegetative bacteria and amplified viral nucleic acid from in-use testing of gastrointestinal endoscopes

Hospital-acquired infection attributed to inadequate decontamination of gastrointestinal endoscopes prompted an in use evaluation of recommended procedures. Specimens were obtained from the internal channels of 123 endoscopes before, during and after decontamination by flushing with saline and brushing with a sterile brush, and examined for vegetative bacteria by broth and plate culture. Four endoscopy units were tested; the chemical disinfectants used were: 2% glutaraldehyde in Centres 1 and 2 (automated) and Centre 3 (manual); peracetic acid in Centre 4 (automated). Samples from patients in Centre 1 with known chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1) infection were also examined for viral nucleic acid by ultracentrifugation, nucleic acid extraction, reverse transcription (for RNA) and polymerase chain reaction (PCR). No persistent vegetative bacteria were found following standard manual cleaning and disinfection for 20 min in 2% glutaraldehyde in Centres 2 and 3 (N = 37). At Centre 1, while plate culture yielded no growth, 34% of samples (10/29) grew vegetative bacteria in broth culture after cleaning and disinfection for 20 min in 2% glutaraldehyde. Investigation revealed an error in manual cleaning; no bacteria were detected in 37 samples taken after this was corrected. At Centre 4, despite the use of peracetic acid as a sterilant, three out of 20 (15%) of post decontamination samples grew bacteria; one contained persistent bacteria. HBV and HCV PCR analysis detected viral nucleic acid in three out of four and four out of six samples from viraemic patients undergoing endoscopy in Centre 1 during the period of improper manual washing. After proper cleaning was instituted, samples from nine out of nine HCV viraemic patients were negative. HIV RNA was detected in five of 14 samples taken from endoscopes after use on HIV positive patients but all post decontamination samples were negative. Detection of bacteria in washes from endoscope channels is a useful warning of a breakdown in decontamination practice. Inadequate brushing of internal channels may result in persistent HCV and HBV viral nucleic acid, the significance of which is not clear. These results reinforce the importance of adequate manual cleaning of endoscopes before chemical disinfection.

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.

Studies of Australia-SH Antigen in Sporadic Viral Hepatitis in London

Sera from 87 patients with acute sporadic viral hepatitis were tested for the presence of the Australia-SH antigen. Forty-three were positive by the complement-fixation test, but only 24 of these reacted in the gel-diffusion test. The antigen was equally distributed in infectious and serum hepatitis. The relationship of naturally occurring antigen-positive hepatitis to the Willow-brook MS-2 type is discussed.

Duck hepatitis B virus DNA in liver, spleen, and pancreas: Analysis by in situ and southern blot hybridization

Tissues from a 10-week-old Pekin duck, experimentally infected at 1 day of age with duck hepatitis B virus (DHBV), were examined for the presence of replicative levels of DHBV DNA by in situ and Southern blot hybridization. Hepatocytes, pancreatic lymphoid follicle, exocrine, and endocrine cells, and splenic mononuclear cells all contained DHBV DNA localized predominantly to the cytoplasm of infected cells. Duck hepatitis B surface antigen distribution in the same tissues correlated well with the presence of DHBV DNA in many of these cells. In hepatocytes and pancreatic islet cells, 60% of DHBV DNA was present as single-stranded DNA, indicating the likelihood of ongoing virus replication in these cell types and providing further evidence that hepadnavirus DNA replication occurs largely within the cell cytoplasm. In contrast, DHBV in mononuclear cells within splenic germinal centers was wholly double-stranded, suggesting that limited, if any, DHBV DNA replication was occurring in this cell type. These data provide further information about the pathogenesis and cell-specific sites of DHBV infection.

Human papillomavirus deoxyribonucleic acid as a prognostic indicator in early-stage cervical cancer: A possible role for type 18☆

OBJECTIVE Our purpose was to determine the prognostic significance of human papillomavirus deoxyribonucleic acid in cervical cancers. STUDY DESIGN The polymerase chain reaction was used to detect human papillomavirus deoxyribonucleic acid types 6, 11, 16, 18, 31, 33, 52, or 58 in tumors from 148 patients (equal numbers of whom were disease free or had relapses) surgically treated for stage IB or IIA cancers in a major Australian hospital. Cox regression modeling was used to assess the effect of human papillomavirus status on tumor recurrence, taking into account patient age, clinical stage, histologic node status, and type of tumor. RESULTS Seventy of 74 (95%) of the recurring tumors and 62 of 74 (84%) of the nonrecurring tumors were human papillomavirus deoxyribonucleic acid positive. The rates of positivity of types 16 and 18 were 64% versus 31% in the recurrers and 65% versus 14% in the nonrecurrers. Human papillomavirus type 18 positivity was associated with a greater risk of recurrence than was type 16 positivity (hazard ratio 1.8; p = 0.03). Clinical stage, nodal metastasis, and young age (< or = 35 years) also had adverse effects on relapse (hazard ratio for each approximately 2). CONCLUSION Human papillomavirus type 18 positivity is a risk factor for tumor recurrence in surgically treated cervical cancer.

Virus-liver cell interactions in duck hepatitis B virus infection: A study of virus dissemination within the liver

Thirty-five 1-day-old Pekin-Aylesbury ducks were inoculated intravenously or intraperitoneally with duck hepatitis B virus, and the time-course of infection was examined by Southern-blot, dot-blot, and in situ hybridization and by immunohistochemistry. Randomly scattered single infected hepatocytes were first seen on days 1 and 2 after inoculation and by day 3 occurred as single cells, pairs, and groups of 5-10 adjoining cells. From day 4 after inoculation all hepatocytes were positive for duck hepatitis B surface antigen and deoxyribonucleic acid. Duck hepatitis B virus deoxyribonucleic acid levels in liver extracts and serum increased logarithmically from days 2 to 3 to a plateau by days 4 to 5 after inoculation. Infected and control birds showed no significant differences during the first 7 days in terms of liver histology, hepatocyte morphology, or mitotic activity. It was concluded that (a) virus gains access to randomly distributed hepatocytes without first replicating in other cell types, and then begins disseminating to adjacent cells following anatomic boundaries; (b) markers of infection in liver and serum show reproducible kinetics, thus making this in vivo system amenable to further quantitative study; and (c) hepatocytes in this system are highly permissive to virus replication without the development of significant cytopathology.

Effects of Phyllanthus plant extracts on duck hepatitis B virus in vitro and in vivo

The effects of extracts of five Australian Phyllanthus species (P. hirtellus, P. gunnii, P. gasstroemii, P. similis and P. tenellus), other plant extracts and the antiviral drug foscarnet on duck hepatitis B virus (DHBV) endogenous DNA polymerase (DNAp) activity were compared. All 5 Phyllanthus species caused 50% inhibition at concentrations of dry weight between 350-800 micrograms/ml, which is comparable with the effect described for P. amarus on the DNAp of human and woodchuck hepatitis B viruses. Incubation of P. hirtellus with 100 ID50 DHBV neutralized infection. However, neither P. gasstroemi extract, given by intraperitoneal injection (i.p.) at a dose of 20 mg/kg 3 times per week to ducklings early in the incubation period, or P. hirtellus extract, given to established DHBV carrier ducklings, prevented or eliminated infection.