Bacteriology of endotracheal tube biofilms and antibiotic resistance: a systematic review

Bacteria commonly adhere to surfaces and produce polymeric material to encase the attached cells to form communities called biofilms. Within these biofilms, bacteria can appear to be many times more resistant to antibiotics or disinfectants. This systematic review explores the prevalence and microbial profile associated with biofilm production of bacteria isolated from endotracheal tubes and its associations with antimicrobial resistance. A comprehensive search was performed on databases PubMed, Embase, and Google Scholar for relevant articles published between 1st January 2000 and 31st December 2022. The relevant articles were exported to Mendeley Desktop 1.19.8 and screened by title and abstract, followed by full text screening based on the eligibility criteria of the study. Quality assessment of the studies was performed using the Newcastle-Ottawa Scale (NOS) customized for cross-sectional studies. Furthermore, the prevalence of antimicrobial resistance in biofilm-producers isolated from endotracheal tube specimens was investigated. Twenty studies encompassing 981 endotracheal tubes met the eligibility criteria. Pseudomonas spp. and Acinetobacter spp. were predominant isolates among the biofilm producers. These biofilms provided strong resistance against commonly used antibiotics. The highest resistance rate observed in Pseudomonas spp. was against fluoroquinolones whereas the least resistance was seen against piperacillin-tazobactam. A similar trend of susceptibility was observed in Acinetobacter spp. with a very high resistance rate against fluoroquinolones, third-generation cephalosporins and carbapenems. In conclusion, endotracheal tubes were associated with colonization by biofilm forming bacteria with varying levels of antimicrobial resistance. Biofilms may promote the occurrence of recalcitrant infections in endotracheal tubes which need to be managed with appropriate protocols and antimicrobial stewardship. Research focus should shift towards meticulous exploration of biofilm-associated infections to improve detection and management.

Pharmacokinetic Variables of Dapagliflozin/Metformin Extended-release Fixed-dose Combination in Healthy Chinese Volunteers and Regional Comparison

PURPOSE

A fixed-dose combination (FDC) product combining dapagliflozin and metformin may increase medication adherence in patients with type 2 diabetes mellitus (T2DM) by minimizing pill burden associated with co-administration of individual component (IC) formulations and, consequently, improve cost-efficiency and compliance. This study evaluated the bioequivalence of the dapagliflozin/metformin FDC product versus IC administration in healthy volunteers from a Chinese population and assessed the safety profile of the FDC product. In addition, pharmacokinetic (PK) and safety comparisons of dapagliflozin and metformin across different regions were conducted to evaluate regional differences.

METHODS

This single-center, open-label, parallel-cohort, randomized, 2-period, crossover study enrolled Chinese adults (aged 18-55 years). Volunteers in cohort 1 received either a single FDC tablet of dapagliflozin/metformin extended release (XR) (5/500 mg) or IC tablets (dapagliflozin [5 mg] and metformin XR [500 mg]). Volunteers in cohort 2 received a higher dosage in a similar manner (dapagliflozin [10 mg] and metformin XR [1000 mg]). Volunteers in each cohort were subsequently crossed over to receive the alternate cohort treatment. Plasma concentrations of dapagliflozin and metformin were determined, and bioequivalence analyses were performed under standard fed conditions.

FINDINGS

Eighty healthy Chinese volunteers (89.9% male; mean age, 28.7 years) were randomized into cohort 1 (n = 40) and cohort 2 (n = 39; 1 volunteer withdrew before receiving study treatment). The mean plasma concentration-time profiles of the dapagliflozin and metformin FDC and IC formulations for both doses were found to be nearly superimposable. Dapagliflozin and metformin XR FDC were bioequivalent to the IC tablets, with 90% CIs for each pairwise comparison contained within the 80% to 125% bioequivalence limits. Both the FDC and IC formulations were well tolerated, with no serious adverse events/death. PK parameters for dapagliflozin in the Chinese volunteers were slightly to moderately higher than those from studies conducted in Brazil, Russia, and the United States, and the safety profile of the dapagliflozin/metformin FDC product was consistent with that of other studies. The difference in PK parameters among the 4 regions was not clinically meaningful.

IMPLICATIONS

The bioequivalence of the dapagliflozin/metformin FDC and IC formulations in healthy Chinese adults was established without any new safety concerns. Notably, the observed bioequivalence may be extrapolated to patients with T2DM as the PK parameters of dapagliflozin and metformin in healthy adults are similar to those reported in patients with T2DM.

CLINICALTRIALS

gov identifier: NCT04856007.

Merkel cell carcinoma: a forty-year experience at the Peter MacCallum Cancer Centre

BACKGROUND

Merkel cell carcinoma (MCC) is a rare but highly aggressive neuroendocrine skin malignancy, with Australia having the highest reported incidence in the world. There is currently a lack of consensus regarding optimal management of this disease.

METHODS

This was a retrospective audit conducted by reviewing existing medical records of MCC patients presenting to the Peter MacCallum Cancer Centre (PMCC) between 1980 and 2018. The primary endpoint was locoregional recurrence. The secondary endpoints were distant recurrence, disease-free survival (DFS) and overall survival (OS).

RESULTS

A total of 533 patients were identified. Locoregional recurrence occurring at one, two and 5 years was 24, 31 and 32%, respectively. The estimated 5-year OS and DFS were 46% (95% Confidence Interval [CI] 41-51%) and 34% (95% CI 30-39%) respectively. Older age at diagnosis (hazard ratio [HR] per year = 1.07, 95% CI 1.06-1.07, p < 0.001), and larger primary tumour diameter (HR =1.16, 95% CI 1.03-1.31, p = 0.019) were associated with worse OS on multivariable analysis. Positive or negative histopathological margin status was not associated with OS or DFS differences in patients treated with post-operative radiotherapy.

CONCLUSIONS

In our study, about a third of patients developed locoregional recurrence, distal recurrence or both, and there appears to be no change over the last four decades. If treated with adjuvant radiotherapy, there is no difference in OS or DFS with positive surgical margins. Findings should influence future guidelines.

Exploring the utility of RDoC in differentiating effectiveness amongst antidepressants: A systematic review using proposed psychometrics as the unit of analysis for the Negative Valence Systems domain

Background

RDoC conceptualises psychopathology as neurobiologically-rooted behavioural psychological “constructs” that span dimensionally from normality to pathology, but its clinical utility remains controversial.

Aim

To explore RDoC’s potential clinical utility by examining antidepressant effectiveness through Negative Valence Systems (NVS) domain constructs.

Method

A systematic review was conducted on Web of Science, MEDLINE, EMBASE and PsycINFO for antidepressant trials that included psychometric instruments assessed by Watson, Stanton & Clark (2017) to represent NVS constructs of Acute Threat, Potential Threat and Loss.

Results

221 citations were identified; 13 were included in qualitative synthesis, none for quantitative analysis. All suffered from significant bias risks. 9 antidepressants were investigated, most within 1 construct, and most were found to be effective. Paroxetine, citalopram and fluvoxamine were found to be effective for Acute Threat, fluoxetine, desvenlafaxine and sertraline for Potential Threat, and sertraline, fluvoxamine, fluoxetine and desvenlafaxine effective for Loss. Nefazodone was found to be ineffective for acute fear.

Conclusion

Preliminary evidence supports RDoC NVS constructs’ clinical utility in assessing antidepressant effectiveness, but lack of discriminant validity between Potential Threat and Loss supports their recombination into a single Distress construct. Finding of effectiveness within “normal” construct levels support the utility of a dimensional approach. Testable hypotheses were generated that can further test RDoC’s clinical utility.

Cerebral Venous Thrombosis in Patients with COVID-19 Infection: a Case Series and Systematic Review

BACKGROUND

There has been increasing reports associating the coronavirus disease 2019 (COVID-19) with thromboembolic phenomenon including ischemic strokes and venous thromboembolism. Cerebral venous thrombosis (CVT) is a rare neurovascular emergency that has been observed in some COVID-19 patients, yet much remains to be learnt of its underlying pathophysiology.

OBJECTIVE

We present a case series of local patients with concomitant COVID-19 infection and CVT; and aim to perform a systematic review of known cases in the current literature.

METHODS

We describe two patients with concomitant COVID-19 infection and CVT from a nationwide registry in Singapore. We then conducted a literature search in PubMed and Embase using a suitable keyword search strategy from 1st December 2019 to 11th June 2020. All studies reporting CVT in COVID-19 patients were included.

RESULTS

Nine studies and 14 COVID-19 patients with CVT were studied. The median age was 43 years (IQR=36-58) and majority had no significant past medical conditions (60.0%). The time taken from onset of COVID-19 symptoms to CVT diagnosis was a median of 7 days (IQR=6-14). CVT was commonly seen in the transverse (75.0%) and sigmoid sinus (50.0%); 33.3% had involvement of the deep venous sinus system. A significant proportion of patients had raised D-dimer (75.0%) and CRP levels (50.0%). Two patients reported presence of antiphospholipid antibodies. Most patients received anticoagulation (91.7%) while overall mortality rate was 45.5%.

CONCLUSIONS

The high mortality rate of CVT in COVID-19 infection warrants a high index of suspicion from physicians, and early treatment with anticoagulation should be initiated.

Regulation of nerve growth and patterning by cell surface protein disulphide isomerase

Contact repulsion of growing axons is an essential mechanism for spinal nerve patterning. In birds and mammals the embryonic somites generate a linear series of impenetrable barriers, forcing axon growth cones to traverse one half of each somite as they extend towards their body targets. This study shows that protein disulphide isomerase provides a key component of these barriers, mediating contact repulsion at the cell surface in chick half-somites. Repulsion is reduced both in vivo and in vitro by a range of methods that inhibit enzyme activity. The activity is critical in initiating a nitric oxide/S-nitrosylation-dependent signal transduction pathway that regulates the growth cone cytoskeleton. Rat forebrain grey matter extracts contain a similar activity, and the enzyme is expressed at the surface of cultured human astrocytic cells and rat cortical astrocytes. We suggest this system is co-opted in the brain to counteract and regulate aberrant nerve terminal growth.

ePTFE/FEP stents for malignant biliary obstruction

BACKGROUND

Biliary obstruction due to malignant disease causes debilitating symptoms and palliation of the disease involves placement of biliary stents. Covered self-expanding metal biliary stents may provide a longer patency and a lower risk of complications and dysfunction compared to uncovered stents, making them better for patients' quality of life and cost effectiveness. This study aims to evaluate the indications and outcomes for a group of cases where expanded polytetrafluoroethylene/fluorinated ethylene propylene (ePTFE/FEP) covered metal stents were used to palliate malignant biliary obstruction.

METHODS

All cases of ePTFE/FEP-covered Viabil stent implantation in a 4-year period in a single hospital were identified and details of indications and outcomes for stent placement were recorded. Kaplan-Meier estimator analysis was used to create plots for stent patency and survival time.

RESULTS

The median stent patency was 173 days (standard error of the mean, SE = 54) and the median survival time was 247 days (SE = 88). No complications of stent implantation were recorded and in seven cases no dysfunction was noted. In one case, tumour ingrowth was observed, and in one other case the stent was no longer found in situ on subsequent imaging.

CONCLUSION

The use of the ePTFE/FEP-covered Viabil stent in the palliation of malignant obstruction where indicated is promising, providing a low rate of stent dysfunction and complications. More data need to be collected to conclusively ascertain whether covered stents have a longer patency and lower complication rate compared to uncovered stents.

Creating a community-based comprehensive intervention to improve asthma control in a low-income, low-resourced community

Introduction: Asthma evidence-based interventions (EBI) are implemented in the home, school, community or primary care setting. Although families are engaged in one setting, they often have to navigate challenges in another setting.Objective: Our objective is to design and implement a comprehensive plan which integrates EBI's and connects the four sectors in underserved communities such as Philadelphia.Methods: September 2015-April 2016 we implemented a three-pronged strategy to understand needs and resources of the community including 1) focus groups and key informant interviews, 2) secondary data analysis and 3) pilot testing for implementation to determine gaps in care, and opportunities to overcome those gaps.Results: Analysis of the focus group and key informant responses showed themes: diagnosis fear, clinician time, home and school asthma trigger exposures, school personnel training and communication gaps across all four sectors. EBI's were evaluated and selected to address identified themes. Pilot testing of a community health worker (CHW) intervention to connect home, primary care and school resulted in an efficient transfer of asthma medications and medication administration forms to the school nurse office for students with uncontrolled asthma addressing a common delay leading to poor asthma management in school.Conclusion: Thus far there has been limited success in reducing asthma disparities for low-income minority children. This study offers hope that strategically positioning CHWs may work synergistically to close gaps in care and result in improved asthma control and reduced asthma disparities.

Tunable phonon-cavity coupling in graphene membranes

A major achievement of the past decade has been the realization of macroscopic quantum systems by exploiting the interactions between optical cavities and mechanical resonators. In these systems, phonons are coherently annihilated or created in exchange for photons. Similar phenomena have recently been observed through phonon-cavity coupling-energy exchange between the modes of a single system mediated by intrinsic material nonlinearity. This has so far been demonstrated primarily for bulk crystalline, high-quality-factor (Q > 10(5)) mechanical systems operated at cryogenic temperatures. Here, we propose graphene as an ideal candidate for the study of such nonlinear mechanics. The large elastic modulus of this material and capability for spatial symmetry breaking via electrostatic forces is expected to generate a wealth of nonlinear phenomena, including tunable intermodal coupling. We have fabricated circular graphene membranes and report strong phonon-cavity effects at room temperature, despite the modest Q factor (∼100) of this system. We observe both amplification into parametric instability (mechanical lasing) and the cooling of Brownian motion in the fundamental mode through excitation of cavity sidebands. Furthermore, we characterize the quenching of these parametric effects at large vibrational amplitudes, offering a window on the all-mechanical analogue of cavity optomechanics, where the observation of such effects has proven elusive.

Social prescribing through arts on prescription in a U.K. city: participants' perspectives (part 1)

OBJECTIVES

In the U.K., the era of New Labour witnessed a developing connection between the arts (and sport) and 'neighbourhood renewal'. The concept of the usefulness of the arts to health has gained credence largely through community-based arts. Whilst there is an increasing evidence base for the usefulness of community arts delivery, there is little published evidence in the peer-reviewed literature of the effectiveness of delivery of Arts on Prescription. The aim of this study was therefore to explore the experiences of people who have engaged with Arts on Prescription programme of work.

STUDY DESIGN

This qualitative research study used a narrative inquiry approach amongst participants of Arts on Prescription programme of work.

METHODS

Sixteen in-depth interviews were conducted in community-based arts venues. Each participant was using or had used mental health services.

RESULTS

Participants experienced Arts on Prescription as a creative and therapeutic environment. It was considered a safe place where participants can be creative with others who have shared similar experiences. Participants experienced social, psychological and occupational benefits, although these benefits are not easily separated as they are intermingled. By feeling accepted and amongst people who have had similar experiences, participants also gained a sense of social belonging. A number of participants also found new opportunities for the future.

CONCLUSIONS

Community-based arts groups that are professionally facilitated may provide a therapeutic environment for participants. Participants gained a sense of pride in their work, and experienced psychological, social and occupational benefits.

Arts In-Reach: taking 'bricks off shoulders' in adult mental health inpatient care

This article reports upon a research study focusing on a programme of work called Arts In-Reach. The programme was designed to provide a participatory arts programme for the adult mental health inpatient wards in a city in the UK. The aim of the research study was to explore the experiences of people who have engaged with the Arts In-Reach programme of work. Eleven qualitative interviews were conducted among participants of the programme. Consistent with other research, this study reveals how people on the wards often feel powerless and bored. The feelings of boredom are exacerbated as people recover. Participating in the arts groups has alleviated some of those feelings. Furthermore, participation has also increased people's social interactions and given opportunity for self-expression. The arts activities also provide a distraction for people and some appreciated being able to talk about matters other than their 'illness'. The arts activities helped people to think about their future and how they might take their artwork forward. For some people, thinking about the future helped with restoring a sense of hope, a quality imperative for recovery.

Social prescribing through arts on prescription in a U.K. city: referrers' perspectives (part 2)

OBJECTIVES

This study provides some insight into the perceived benefits of an Arts on Prescription service in the U.K. according to referrers. Social prescribing provides a framework for emerging alternative approaches to mental distress. The aim of this study was to investigate the views of referrers to an Arts on Prescription programme regarding the quality and effectiveness of the service.

STUDY DESIGN

For this study, 10 individuals were recruited from a potential total of 148 referrers who had referred their clients to Arts on Prescription between 2008 and 2011.

METHOD

Qualitative, in-depth semi-structured interviews were conducted and the findings were thematically analysed.

RESULTS

It was evident that referrers value Arts on Prescription. It is considered to be a therapeutic, relaxing and safe environment that is professionally led. Referrers reported that their clients take pride in the work they have created at Arts on Prescription. They believe that the programme helps their clients to build confidence, find meaningful occupation, develop skills and express themselves. The social opportunities provided by the programme are considered significant, as well as the peer support that is evident.

CONCLUSIONS

Social prescribing enables general practitioners to have greater options when helping patients with complex social problems. As such, the programme is clearly valued by referrers for their clients. The programme offers valuable social benefits that are becoming reduced in an era of closure of day service provision. There is concern regarding whether such valuable resources will be commissioned in the future.

Experiences and constructions of art: a narrative-discourse analysis

A narrative-discourse analysis was conducted to study the narratives of mental health service users talking about their engagement with art. The sample was drawn from a group of people who had attended arts workshops organized by a mental health service provider. Eleven people were interviewed and were asked to tell the story of their involvement in art and its significance to their lives. The data were analysed using a discourse analysis approach. Art is constructed as therapeutic within an illness repertoire. Emotions are inseparable from creative expression and identity claims are made in relation to being an artist.

A phase I/II trial of celecoxib with chemotherapy and radiotherapy in the treatment of patients with locally advanced oesophageal cancer

BACKGROUND

The study's aim was to determine the maximum tolerated dose (MTD) of celecoxib combined with chemoradiotherapy (CRT) for locally advanced oesophageal cancer (OC).

METHODS

CRT comprised of 5FU (1000 mg/m(2)/day, days 1-4, weeks 1 & 5), cisplatin (75 mg/m(2), days 1 & 29) and radiotherapy (50 Gy in 25 fractions or 50.4 Gy in 28 fractions). Celecoxib was given daily during CRT at one of five doses (200 mg bd to 600 mg bd). Three to six patients were assigned per dose.

RESULTS

Thirteen patients were recruited before trial closure due to external safety concerns regarding celecoxib. Median follow up was 17 months (95% CI 9 - >39). The highest administered dose was 400 mg bd (n=4) with one dose-limiting toxicity at this level: grade 3 rash. Five (38%) and 8(62%) patients had grade 3 non-haematological and haematological toxicities respectively. No grade 4 toxicities occurred. Radiological response rate was 54% (n=7: all CR). Six patients had resection with one pathological CR. Median progression-free and overall survival were 8.8 (95% CI 5.1 - >24.8) and 19.6 months (95% CI 7.3 - >39) respectively.

CONCLUSIONS

A MTD was not reached. The regimen was tolerable, indicating that celecoxib can be safely administered with CRT for locally advanced OC.

A prospective study to evaluate the impact of FDG-PET on CT-based radiotherapy treatment planning for oesophageal cancer

BACKGROUND AND PURPOSE

This prospective study sought to determine how the use of combined PET/CT for radiotherapy treatment planning of oesophageal cancer would alter the delineation of tumour volumes compared to CT alone if PET/CT is assumed to more accurately represent true disease extent.

PATIENTS AND METHODS

All patients underwent FDG-PET/CT scanning in the radiotherapy treatment position. For each patient, two separate gross tumour volumes (GTV) were defined, one based on CT images alone (GTV-CT) and another based on combined PET/CT data (GTV-PET). Corresponding planning target volumes (PTV) were generated, and separate treatment plans were then produced. For each patient, volumetric analysis of GTV-CT, PTV-CT and GTV-PET was performed to quantify the proportion of PET-avid disease that was not included in the GTV and PTV (geographic miss) if CT data alone were used for radiotherapy planning. Assessment of the cranial and caudal extent of the primary oesophageal tumour as defined by CT alone vs PET/CT was also compared.

RESULTS

The addition of PET information altered the clinical stage in 8 of 21 eligible patients enrolled on the study (38%); 4 patients had distant metastatic disease and 4 had unsuspected regional nodal disease. Sixteen patients proceeded to the radiotherapy planning phase of the study and received definitive chemoradiation planned with the PET/CT data set. The GTV based on CT information alone excluded PET-avid disease in 11 patients (69%), and in five patients (31%) this would have resulted in a geographic miss of gross tumour. The discordance between CT and PET/CT was due mainly to differences in defining the longitudinal extent of disease in the oesophagus. The cranial extent of the primary tumour as defined by CT vs PET/CT differed in 75% of cases, while the caudal extent differed in 81%.

CONCLUSIONS

This study demonstrates that if combined PET/CT is used for radiotherapy treatment planning, there may be alterations to the delineation of tumour volumes when compared to CT alone, with the potential to avoid a geographic miss of tumour.

3D conformal radiotherapy for gastric cancer--results of a comparative planning study

BACKGROUND AND PURPOSE

Many radiation oncologists are reluctant to use anteroposterior-posteroanterior (AP-PA) field arrangements when treating gastric cancer with adjuvant postoperative radiotherapy due to concerns about normal tissue toxicity, particularly in relation to the kidneys and spinal cord. In this report, we describe a multiple-field conformal radiotherapy technique, and compare this technique to the more commonly used AP-PA technique that was used in the recently reported Intergroup study (INT0116).

MATERIALS AND METHODS

Fifteen patients with stages II-IV adenocarcinoma of the stomach were treated with adjuvant postoperative chemoradiotherapy using a standardised 3D conformal radiotherapy technique that consisted of a 'split-field', mono-isocentric arrangement employing 6 radiation fields. For each patient, a second radiotherapy treatment plan was generated utilising AP-PA fields. The two techniques were then compared for target volume coverage and dose to normal tissues using dose volume histogram (DVH) analysis.

RESULTS

The conformal technique provides more adequate coverage of the target volume with 99% of the planning target volume (PTV) receiving 95% of the prescribed dose, compared to 93% using AP-PA fields. Comparative DVHs for the right kidney, left kidney and spinal cord demonstrate lower radiation doses using the conformal technique, and although the liver dose is higher, it is still well below liver tolerance.

CONCLUSIONS

3D conformal radiotherapy produces superior dose distributions and reduced radiation doses to the kidneys and spinal cord compared to AP-PA techniques, with the potential to reduce treatment toxicity.

High-performance liquid chromatographic determination of polysorbate 80 in pharmaceutical suspensions

A quick HPLC method is reported for the analysis of polysorbate 80 in pharmaceutical suspensions. A typical pharmaceutical suspension was mixed with dilute potassium hydroxide, and heated at 40 degrees C for 6 h. This procedure resulted in quantitative hydrolysis of polysorbate 80 to release oleic acid. A quick HPLC procedure was used to analyze the hydrolyzed samples without further sample treatment. Polysorbate 80 USP, treated in the same way as the pharmaceutical suspensions, was used as standard. Full validation tests were carried out and the validation studies demonstrated that this method is suitable for accurate and reproducible analysis of polysorbate 80 in pharmaceutical suspensions.

Use of endoscopic mucosal clips in radiotherapy planning for oesophageal carcinoma: a series of three cases

This paper describes the technique of placing endoscopic mucosal clips to localize oesophageal carcinoma and hence facilitate radiotherapy planning. This technique has been used on three patients in our centre. One was treated radically with external beam radiotherapy and two were treated palliatively (retreatment) with intraluminal brachytherapy. Mucosal hemoclips were placed at the time of endoscopy to indicate the superior and inferior extent of the tumour. The clips provided a radiologically-recognisable marker of the tumour extent and were visible on simulation films or planning CT scans. The radiation portal included the tumour as demarcated by the clips with an adequate margin. There were no complications related to the placement of the clips. All patients completed the radiotherapy course as planned.

Cytologic evaluation of surgical irrigation fluid following resection of head and neck squamous cell carcinoma

INTRODUCTION

Historically, squamous cells exfoliated from head and neck carcinoma resection have been implicated in locoregional recurrence, but there have been few studies demonstrating the presence of these cells. This study was designed to evaluate the presence of exfoliated malignant cells in surgical irrigation fluid collected during head and neck cancer resection.

METHODS

Thirty patients undergoing surgery for biopsy-proven squamous cell carcinoma had their surgical sites irrigated with 1,000 cc of normal saline. Surgical gloves and instruments were also washed. These samples were prepared and stained using standard squamous cell cytologic stains. All cases were reviewed by one cytopathologist.

RESULTS

Eighteen patients (60%) had positive or suspicious cytology detected in at least one of the surgical samples. In patients with T0 and T1 tumours, all surgical samples were negative. Positive or suspicious cytology was detected in the primary site and glove and instrument irrigation in 40% of patients with T2 tumours, 42% of patients with T3 tumours, and 50% of patients with T4 tumours. This was statistically significant (p < .05). Positive or suspicious cytology was detected in the neck and glove and instrument irrigation in 29% of patients with an N0 neck, 31% of patients with an N1 neck, 39% of patients with an N2 neck, and 100% of patients with an N3 neck. Five of seven patients (71%) with previous radiation therapy had positive or suspicious cytology in at least one of the surgical samples.

CONCLUSIONS

Higher tumour and nodal staging and a previous history of radiation therapy are associated with an increased incidence of positive or suspicious cytology in surgical irrigation fluid. These findings have implications for surgical protocols.

A radiological technique for the assessment of wear in prosthetic knee replacements

OBJECTIVE

Wear of the polyethylene insert is a well-recognised cause of implant failure in total knee replacements. The purpose of this study was to evaluate a simple, digital fluoroscopic technique for the assessment of wear in knee prostheses.

DESIGN

Fluoroscopic images of knee prostheses were produced both of a phantom and in a patient group. Joint space thickness was measured by reference to a known diameter. Measurements were made to assess repeatability of positioning, inter-and intra-observer variance and the effect of angulation.

RESULTS

Standard phantom images showed small variation between measurements, high inter-reader correlation (Pearson's correlation coefficient, r=0.98, P<0.001; coefficient of variation=0.53%) and low intra-reader variation (coefficient of variation=0.57%). Inter- and intra-imager variation were low (coefficient of variation=1.05% and 0.88%, respectively). In the patient group, the range of joint space measurements was 1.9-8.9 mm. The coefficient of variation in insert measurements on repeated images was 2.0%. Repeatability of measurements was 0.2 mm with 99% confidence interval.

CONCLUSIONS

This technique allows repeatable, precise measurement of insert thickness. The technique may be adapted to any implant where a reliable calibrating distance is present.

Characterization of a new human B7-related protein: B7RP-1 is the ligand to the co-stimulatory protein ICOS

Optimal T cell activation requires the interactions of co-stimulatory molecules, such as those in the CD28 and B7 protein families. Recently, we described the co-stimulatory properties of the murine ligand to ICOS, which we designated as B7RP-1. Here, we report the co-stimulation of human T cells through the human B7RP-1 and ICOS interaction. This ligand-receptor pair interacts with a K:(D) approximately 33 nM and an off-rate with a t((1/2)) > 10 min. Interestingly, tumor necrosis factor (TNF)-alpha differentially regulates the expression of human B7RP-1 on B cells, monocytes and dendritic cells (DC). TNF-alpha enhances B7RP-1 expression on B cells and monocytes, while it inhibits it on DC. The human B7RP-1-Fc protein or cells that express membrane-bound B7RP-1 co-stimulate T cell proliferation in vitro. Specific cytokines, such as IFN-gamma and IL-10, are induced by B7RP-1 co-stimulation. Although IL-2 levels are not significantly increased, B7RP-1 co-stimulation is dependent on IL-2. These experiments define the human ortholog to murine B7RP-1 and characterize its interaction with human ICOS.

Clinical findings, imaging characteristics and outcome in catastrophic post-encephalitic epilepsy

OBJECTIVES

The aim of this study is to characterize the clinical features and prognostic factors for intractable, post-encephalitic epilepsy.

METHODS

We studied retrospectively 42 patients (26 men) evaluated between 1982 and 1999. MRI, neuropsychological findings, interictal and ictal scalp EEG were reviewed for all patients. Fifteen patients had additional stereo EEG (SEEG) studies.

RESULTS

The mean age at encephalitis was 17 years (SD = 15.5); etiology was identified in 18 patients. During the acute illness, 79% had status epilepticus (SE) or recurrent seizures and 76% were in coma; mean Glasgow outcome scale (GOS) was 3.6 (SD = 0.8). The mean latency to seizure onset was 0.8 years (SD = 1.9). The majority (72%) presented with complex partial seizures with or without secondary generalization. According to interictal epileptiform findings and the predominant seizure onset pattern as found on scalp EEG, patients were unilateral temporal (UTLE) = 8, bilateral temporal (BTLE) = 12, and extratemporal/multifocal or generalized (ETMFE) = 22 patients. MRI atrophy and/or signal changes were unilateral temporal in 7 (18%), bilateral temporal in 5 (13%), multilobar/diffuse in 20 (51%), and absent in 7 (18%). ANOVA revealed significant differences in mean GOS between UTLE versus BTLE and ETMFE (4.7 versus 3.2 versus 3.6; p < 0.0001), but not in age at encephalitis. Latency to the first unprovoked seizure was shorter in patients with ETMFE compared to UTLE and BTLE (p < 0.01). Surgery was performed in 24 patients. The best outcome was obtained in UTLE (7/8 class I and II). In the others, outcome was poor in the majority (13/16 class III and IV).

CONCLUSION

There is a small subgroup of patients with postencephalitic UTLE for whom the outcome is favorable. The majority of our patients had multifocal seizure onset with BTLE and ETMFE, and poor outcome after surgical treatment.

Successful epilepsy surgery in catastrophic postencephalitic epilepsy

The authors studied prognostic factors for surgical treatment in 22 patients with intractable postencephalitic epilepsy. A small subgroup of patients (9/22) had a positive outcome after resective surgery. They had a higher functional level after encephalitis as measured by Glasgow Outcome Score, a longer time interval between encephalitis and onset of seizures, and localization of ictal EEG to one temporal lobe. The other patients had devastating seizures with poor outcome after surgery.

Altered p21(WAF1/CIP1) expression is associated with poor prognosis in extrahepatic bile duct carcinoma

This study was designed to determine the clinical implications of p21(WAF1/CIP1) expression and the relationship between p21(WAF1/CIP1) expression and p53 status in extrahepatic bile duct carcinoma (EBDC). Low p21(WAF1/CIP1) expression was immunohistochemically detected in 23 (67.6%) of 34 EBDCs, moderate in six (17.7%), and high in five (14.7%). Kaplan-Meier curves showed that low and high p21(WAF1/CIP1) expressions were significantly associated with shortened disease-free survival (low vs. moderate, P=0.02; high vs. moderate, P=0.01). There was no correlation between p21(WAF1/CIP1) and p53 expression. These findings suggest that altered p21(WAF1/CIP1) expression exerts an adverse influence on the prognosis of EBDC.

T-cell co-stimulation through B7RP-1 and ICOS

T-cell activation requires co-stimulation through receptors such as CD28 and antigen-specific signalling through the T-cell antigen receptor. Here we describe a new murine costimulatory receptor-ligand pair. The receptor, which is related to CD28 and is the homologue of the human protein ICOS, is expressed on activated T cells and resting memory T cells. The ligand, which has homology to B7 molecules and is called B7-related protein-1 (B7RP-1), is expressed on B cells and macrophages. ICOS and B7RP-I do not interact with proteins in the CD28-B7 pathway, and B7RP-1 co-stimulates T cells in vitro independently of CD28. Transgenic mice expressing a B7RP-1-Fc fusion protein show lymphoid hyperplasia in the spleen, lymph nodes and Peyer's patches. Presensitized mice treated with B7RP-1-Fc during antigen challenge show enhanced hypersensitivity. Therefore, B7RP-1 exhibits co-stimulatory activities in vitro and in vivo. ICOS and B7RP-1 define a new and distinct receptor-ligand pair that is structurally related to CD28-B7 and is involved in the adaptive immune response.

Folding and purification of a recombinantly expressed interferon regulatory factor, IRF-4

Interferon regulatory factor 4 (IRF-4), an intracellular, multidomain protein, is a member of the interferon regulatory factor family and a lymphoid-specific transcription factor that can form a ternary complex with DNA and the transcription factor PU.1. Recombinant human IRF-4 was expressed in Escherichia coli and purified from the soluble cell extract and the insoluble inclusion bodies. The inclusion bodies were solubilized with guanidinium-hydrochloride and sequentially buffer exchanged into urea- and then NaCl-containing solutions. This two-step process for the removal of the denaturants was the critical step to allow for the correct folding of IRF-4. Following purification through immobilized metal affinity, hydrophobic interaction, and gel permeation chromatographies, the renatured protein was shown to be structurally and physically equivalent to a sample of IRF-4 produced in the soluble fraction of E. coli cells. This was confirmed by near and far UV circular dichroism analysis, including thermal stability analysis. The purified IRF-4 was also shown to be capable of binding DNA in a PU.1-dependent manner by electrophoretic mobility shift analysis. The protein folding and purification methods are suitable for producing large quantities of full-length IRF-4.

Clinical audit of a new radiation oncology department in the first 20 months of establishment

This audit was carried out to examine the workload statistics of the Radiation Oncology Department at Liverpool Hospital in its first 20 months of operation, and their implications for the delivery of radiation oncology services in the Southwestern Sydney Area Health Service (SWSAHS). Data on patient demographics, primary diagnosis and radiotherapy treatment details from April 1995 to December 1996 were analysed. In this time period, 1329 new patients were seen; 90.6% of them lived in the local area health service and approximately 30% came from a non-English-speaking background. The most common primary tumour sites were breast (25%), prostate (17%) and lung (15%). Nine hundred and ninety-eight of the new patients (74%) proceeded to have radiotherapy. Fifty-seven per cent were treated radically with curative or adjuvant intent, the remainder were treated palliatively for symptom control or local control. The most commonly used fractionation schedules were 31-35 fractions for radical treatment and 1-5 fractions for palliative treatment. Forty patients (4%) did not complete the treatment course as planned. Eighty-nine patients (9%) were retreated in the same time period. These workload statistics were helpful in determining ongoing workload and planning future expansion.

Inhibition of activator protein 1 activity by paclitaxel suppresses interleukin-1-induced collagenase and stromelysin expression by bovine chondrocytes

OBJECTIVE

Cytokine-induced collagenase 1 (matrix metalloproteinase 1 [MMP-1]) and stromelysin 1 (MMP-3) expression is dependent on activator protein 1 (AP-1) activation and have a fundamental role in the pathophysiology of arthritic diseases by degrading connective tissues. This study evaluates the effect of paclitaxel on AP-1 activation and examines its effect on the expression of 2 major matrix metalloproteinases, MMP-1 and MMP-3, and its effect on AP-1 activation.

METHODS

MMP-1, MMP-3, c-fos, and c-jun messenger RNA (mRNA) levels were measured in interleukin-1 (IL-1)-induced primary chondrocytes in the presence and absence of paclitaxel. The effect of paclitaxel on AP-1 promoter activity was studied by chloramphenicol acetyltransferase assays in IL-1-stimulated chondrocytes. The same conditions were applied to studies of the effect of paclitaxel on binding at the AP-1 site by gel-shift mobility assays. The cytotoxicity effect of paclitaxel on chondrocytes was studied by examining cell viability and expression of the matrix molecules aggrecan and type II collagen.

RESULTS

IL-1-induced MMP-1 and MMP-3 mRNA levels were markedly reduced in paclitaxel-treated chondrocytes. Further, IL-1-induced AP-1 activation and AP-1 binding were inhibited by paclitaxel. However, there was no effect on the expression of c-fos or c-jun mRNA levels. Chondrocyte viability was not affected by paclitaxel, and there was no effect on the expression of housekeeping genes or the major cartilage matrix molecules aggrecan and type II collagen.

CONCLUSION

These studies demonstrate that paclitaxel is a potent inhibitor of MMP-1 and MMP-3 synthesis through the AP-1 site. However, inhibition of AP-1 activity by paclitaxel does not affect the viability of chondrocytes or the expression of matrix molecules.

Trace Element Concentrations in Two Subpopulations of Lesser Snow Geese from Wrangel Island, Russia

Lesser snow geese (Anser c. caerulescens) from the Wrangel Island, Russia breeding colony spend the winter in two widely separated areas: the northern subpopulation in southern British Columbia and northern Washington and the southern subpopulation in the Central Valley of California. We examined 19 trace elements in the eggs and livers of geese from these two subpopulations to examine whether geese from the different wintering areas have similar trace element burdens. Eggs collected at the breeding colony from geese of the southern subpopulation had slightly higher levels of manganese, an element that can cause neurological damage and behavioral changes in chicks, than geese of the northern subpopulation. Livers from adult geese collected on the two wintering areas showed significant differences in trace elements including copper, iron, magnesium, molybdenum, and zinc. Copper concentrations in the livers of geese from the southern subpopulation were much higher than those from the northern subpopulation (&xmacr; = 116 vs. 46 ppm; dry weight). Elevated levels of copper may induce anemia in birds. The differences in trace element concentrations of these two subpopulations may be related to farming practices in their wintering areas. Geese from the northern subpopulation feed in pastures and coastal marshes and migrate along the coast, but geese from the southern subpopulation feed predominantly in rice fields and migrate over farm land. Copper and manganese are major components of fertilizers and fungicides commonly applied during rice cultivation.