It Takes Two to Tangle: Microneedle Patches Co-delivering Monoclonal Antibodies and Engineered Antimicrobial Peptides Effectively Eradicate Wound Biofilms

Wound biofilms pose a great clinical challenge. Herein, this work reports a dissolvable microneedle patch for dual delivery of monoclonal antibodies anti-PBP2a and engineers antimicrobial peptides W379. In vitro antibacterial efficacy testing with microneedle patches containing a combination of 250 ng mL-1 W379 and 250 ng mL-1 anti-BPB2a decreases the bacterial count from ≈3.31 × 107 CFU mL-1 to 1.28 × 102 CFU mL-1 within 2 h without eliciting evident cytotoxicity. Ex vivo testing indicates W379 and anti-PBP2a co-loaded microneedle patch displayed a remarkable reduction of bacterial load by ≈7.18 log CFU after administered only once within 48 h. The bacterial count is significantly diminished compared to the treatment by either W379 or anti-PBP2a-loaded alone microneedle patches. When administered twice within 48 h, no bacteria are identified. Further in vivo study also reveals that after two treatments of W379 and anti-PBP2a co-loaded PVP microneedle patches within 48 h, the bacterial colonies are undetectable in a type II diabetic mouse wound biofilm model. Taken together, W379 and anti-PBP2a co-loaded PVP microneedle patches hold great promise in treating wound biofilms.

Outcomes of Negative Pressure Wound Therapy on Immediate Breast Reconstruction after Mastectomy

Immediate expander/implant-based breast reconstruction after mastectomy has become more sought after by patients. Although many patients choose this technique due to good aesthetic outcomes, lack of donor site morbidity, and shorter procedure times, it is not without complications. The most reported complications include seroma, infection, hematoma, mastectomy flap necrosis, wound dehiscence, and implant exposure, with an overall complication rate as high as 45%. Closed incision negative pressure therapy (ciNPT) has shown value in wound healing and reducing complications; however, the current literature is inconclusive. We aimed to examine if ciNPT improves outcomes for patients receiving this implant-based reconstruction.

Methods

This is a retrospective single-institution study evaluating the ciNPT device, 3M Prevena Restor BellaForm, on breast reconstruction patients. The study was performed between July 1, 2019 and October 30, 2020, with 125 patients (232 breasts). Seventy-seven patients (142 breasts) did not receive the ciNPT dressing, and 48 patients (90 breasts) received the ciNPT dressing. Primary outcomes were categorized by major or minor complications. Age, BMI, and final drain removal were summarized using medians and quartiles, and were compared with nonparametric Mann-Whitney test. Categorical variables were compared using chi-square or Fisher exact test.

Results

There was a statistically significant reduction in major complications in the ciNPT group versus the standard dressing group (P = 0.0247). Drain removal time was higher in the ciNPT group.

Conclusion

Our study shows that ciNPT may help reduce major complication rates in implant-based breast reconstruction patients.

Triggered release of antimicrobial peptide from microneedle patches for treatment of wound biofilms

Biofilms pose a great challenge for wound management. Herein, this study describes a near-infrared (NIR) light-responsive microneedle patch for on-demand release of antimicrobial peptide for treatment of wound biofilms. IR780 iodide as a photothermal conversion agent and molecularly engineered peptide W379 as an antimicrobial agent are loaded in dissolvable poly(vinylpyrrolidone) (PVP) microneedle patches followed by coating with a phase change material 1-tetradecanol (TD). After placing in an aqueous solution or biofilm containing wounds ex vivo and in vivo, upon exposure to NIR light, the incorporated IR780 induces light-to-heat conversion, causing the melting of TD. This leads to the dissolution of PVP microneedles, enabling the release of loaded W379 peptide from the microneedles into surrounding regions (e.g., solution, biofilm, wound bed). Compared with traditional microneedle patches, NIR light responsive microneedle patches can program the release of antimicrobial peptide and show high antibacterial efficacy in vitro. Meanwhile, this work indicates that NIR light responsive TD-coated, W379-loaded PVP microneedle patches show excellent antibiofilm activities ex vivo and in vivo. Additionally, this microneedle system could be a promising platform for delivering other antimicrobial agents.

1245 HEALTH CARE WORKERS’ EXPERIENCES ON WORKING AT RESIDENTIAL CARE HOME FOR THE ELDERLY: AN INTEGRATIVE REVIEW

Introduction

The ageing population poses challenges to the health care industry worldwide. The huge demand for residential care home for the elderly (RCHE) services induces pressure on health care workers (HCWs) recruitment and retention. HCWs are personnel who have prominent roles in direct basic care to the older adults, and all kinds of hands-on care. Due to the “unpleasant” work nature, shift work, and physical demands for HCWs, it is essential to unfold how HCWs comprehend their working experiences.

Methods

An integrative review was conducted to synthesize various streams of literature in order to generate new knowledge. Multiple databases such as CINAHL, ERIC, LWW nursing were adopted to search for relevant literature published between 2012 and 2022.

Results

A total of 24 articles were retrieved at the initial stage, and 7 articles were sorted after in-depth review. In general, results supported that HCWs experienced positively on the works at RCHEs though there were job stresses. The HCWs perceived the roles at RCHEs as routinized and task-oriented by providing direct care to older adults. They perceived their roles at RCHEs as care providers who provided direct care to older adults. Also, their responsibilities to maintain the safety and dignity of older adults was expressed as utmost importance. The meaning of works lay on three levels: interpersonal (e.g. self-achievement), interpersonal (e.g. communication with team members), and job performance (e.g. task compliance).

Conclusions

This study reveals the experiences of working at RCHE from the HCWs’ perspective. The HCWs’ experiences reflected in this study as well as the meaning of works discovered can generate insights for policy-makers on HCWs recruitment and retention.

Acknowledgement

The work described in this abstract was fully supported by a grant from the Research Grants Council of HKSAR, China [RGC: UGC/FDS16/M12/20].

Association between tocilizumab treatment of hyperinflammatory patients with COVID-19 in a critical care setting and elevated incidence of hospital-acquired bacterial and invasive fungal infections

Background

Tocilizumab is an interleukin-6 inhibitor that reduces mortality and the need for invasive mechanical ventilation, while increasing the possibility of successful hospital discharge for hyperinflammatory patients with severe coronavirus disease 2019 (COVID-19). No increase in adverse events or serious infections has been reported previously.

Aim

To describe the characteristics and outcomes of patients with severe COVID-19 in critical care who received tocilizumab, and to compare mortality and length of hospital stay for patients who received tocilizumab (N=41) with those who did not (N=33).

Methods

Retrospective review of data related to patients with COVID-19 who received tocilizumab in a critical care setting from 1^st January to 31^st December 2021.

Findings

Amongst COVID-19 survivors, those who had received tocilizumab had longer intensive care unit (ICU) stays (median length 21 vs 9 days) and hospital stays (45 vs 34 days) compared with those who had not received tocilizumab. Thirty-day mortality (29% vs 36%; P=0.5196) and 60-day mortality (37% and 42%; P=0.6138) were not significantly lower in patients who received tocilizumab. Serious bacterial and fungal infections occurred at higher frequency amongst patients who received tocilizumab [odds ratio (OR) 2.67, 95% confidence interval (CI) 1.04–6.86; P=0.042], and at significantly higher frequency than in non-COVID-19 ICU admissions (OR 5.26, 95% CI 3.08–9.00; P<0.0001).

Conclusions

In this single-centre study, patients in critical care with severe COVID-19 who received tocilizumab had a greater number of serious bacterial and fungal infections, but this may not have been a direct effect of tocilizumab treatment.

Codelivery of 1α,25-Dihydroxyvitamin D3 and CYP24A1 Inhibitor VID400 by Nanofiber Dressings Promotes Endogenous Antimicrobial Peptide LL-37 Induction

Surgical site infections represent a significant clinical problem. Herein, we report a nanofiber dressing for topical codelivery of immunomodulating compounds including 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) and VID400, a CYP24A1 inhibitor in a sustained manner, for inducing the expression of the endogenous cathelicidin antimicrobial peptide (CAMP) gene encoding the hCAP18 protein, which is processed into the LL-37 peptide. Nanofiber wound dressings with coencapsulation of 1,25(OH)₂D₃ and VID400 were generated by electrospinning. Both 1,25(OH)₂D₃ and VID400 were coencapsulated into nanofibers with loading efficiencies higher than 90% and exhibited a prolonged release from nanofiber membranes longer than 28 days. Incubation with 1,25(OH)₂D₃/VID400-coencapsulated poly(ϵ-caprolactone) nanofiber membranes greatly induced the hCAP18/LL-37 gene expression in monocytes, neutrophils, and keratinocytes in vitro. Moreover, the administration of 1,25(OH)₂D₃/VID400-coencapsulated nanofiber membranes dramatically promoted the hCAP18/LL-37 expression in dermal wounds created in both human CAMP transgenic mice and human skin tissues. The 1,25(OH)₂D₃- and VID400-coencapsulated nanofiber dressings enhanced innate immunity via the more effective induction of antimicrobial peptide than the free drug alone or 1,25(OH)₂D₃-loaded nanofibers. Together, 1,25(OH)₂D₃/VID400-embedded nanofiber dressings presented in this study show potential in preventing surgical site infections.

Simultaneous Delivery of Multiple Antimicrobial Agents by Biphasic Scaffolds for Effective Treatment of Wound Biofilms

Biofilms pose a major challenge to control wound-associated infections. Due to biofilm impenetrability, traditional antimicrobial agents are often ineffective in combating biofilms. Herein, a biphasic scaffold is reported as an antimicrobial delivery system by integrating nanofiber mats with dissolvable microneedle arrays for the effective treatment of bacterial biofilms. Different combinations of antimicrobial agents, including AgNO3 , Ga(NO3 )3 , and vancomycin, are incorporated into nanofiber mats by coaxial electrospinning, which enables sustained delivery of these drugs. The antimicrobial agents-incorporated dissolvable microneedle arrays allow direct penetration of drugs into biofilms. By optimizing the administration strategies, drug combinations, and microneedle densities, biphasic scaffolds are able to eradicate both methicillin-resistant Staphylococcus aureus (MRSA) and MRSA/Pseudomonas aeruginosa blend biofilms in an ex vivo human skin wound infection model without necessitating surgical debridement. Taken together, the combinatorial system comprises of nanofiber mats and microneedle arrays can provide an efficacious delivery of multiple antimicrobial agents for the treatment of bacterial biofilms in wounds.

Dissolvable Microneedles Coupled with Nanofiber Dressings Eradicate Biofilms via Effectively Delivering a Database-Designed Antimicrobial Peptide

Biofilms in chronic wounds, including diabetic foot ulcers, pressure ulcers, and venous leg ulcers, pose a major challenge to wound management. Herein, we report a Janus-type antimicrobial dressing for eradication of biofilms in chronic wounds. The dressing consists of electrospun nanofiber membranes coupled with dissolvable microneedle arrays to enable effective delivery of a database-designed antimicrobial peptide to both inside and outside biofilms. This antimicrobial dressing exhibited high efficacy against a broad spectrum of resistant pathogens in vitro. Importantly, such a dressing was able to eradicate methicillin-resistant Staphylococcus aureus (MRSA) biofilms in both an ex vivo human skin wound infection model and a type II diabetic mouse wound infection model after daily treatment without applying surgical debridement. Most importantly, the dressing can also completely remove the Pseudomonas aeruginosa and MRSA, dual-species biofilm in an ex vivo human skin infection model. In addition, our computational simulations also suggested that microneedles were more effective in the delivery of peptides to the biofilms than free drugs. Our results indicate that the Janus-type antimicrobial dressings may provide an effective treatment and management of chronic wound polymicrobial infections.

Mesenchymal stem cell-laden, personalized 3D scaffolds with controlled structure and fiber alignment promote diabetic wound healing

The management of diabetic wounds remains a major therapeutic challenge in clinics. Herein, we report a personalized treatment using 3D scaffolds consisting of radially or vertically aligned nanofibers in combination with bone marrow mesenchymal stem cells (BMSCs). The 3D scaffolds have customizable sizes, depths, and shapes, enabling them to fit a variety of type 2 diabetic wounds. In addition, the 3D scaffolds are shape-recoverable in atmosphere and water following compression. The BMSCs-laden 3D scaffolds are capable of enhancing the formation of granulation tissue, promoting angiogenesis, and facilitating collagen deposition. Further, such scaffolds inhibit the formation of M1-type macrophages and the expression of pro-inflammatory cytokines IL-6 and TNF-α and promote the formation of M2-type macrophages and the expression of anti-inflammatory cytokines IL-4 and IL-10. Taken together, BMSCs-laden, 3D nanofiber scaffolds with controlled structure and alignment hold great promise for the treatment of diabetic wounds. STATEMENT OF SIGNIFICANCE: In this study, we developed 3D radially and vertically aligned nanofiber scaffolds to transplant bone marrow mesenchymal stem cells (BMSCs). We personalized 3D scaffolds that could completely match the size, depth, and shape of diabetic wounds. Moreover, both the radially and vertically aligned nanofiber scaffolds could completely recover their shape and maintain structural integrity after repeated loads with compressive stresses. Furthermore, the BMSCs-laden 3D scaffolds are able to promote granulation tissue formation, angiogenesis, and collagen deposition, and switch the immune responses to the pro-regenerative direction. These 3D scaffolds consisting of radially or vertically aligned nanofibers in combination with BMSCs offer a robust, customizable platform potentially for a significant improvement of managing diabetic wounds.

Modified Delphi study of decision-making around treatment sequencing in relapsing-remitting multiple sclerosis

BACKGROUND AND PURPOSE

Existing effectiveness models of disease-modifying drugs (DMDs) for relapsing-remitting multiple sclerosis (RRMS) evaluate a single line of treatment; however, RRMS patients often receive more than one lifetime DMD. To develop treatment sequencing models grounded in clinical reality, a detailed understanding of the decision-making process regarding DMD switching is required. Using a modified Delphi approach, this study attempted to reach consensus on modelling assumptions.

METHODS

A modified Delphi technique was conducted based on three rounds of discussion amongst an international group of 10 physicians with expertise in RRMS.

RESULTS

The panel agreed that the expected time from disease onset to Expanded Disability Status Scale 6.0 is a proxy for disease severity as well as suitable for classifying severity into three groups. A modelled clinical decision rule regarding the timing of switching should contain at least the time between relapses, magnetic resonance imaging outcomes and the occurrence/risk of adverse events. The experts agreed that the assessment of adverse event risk for a DMD is dependent on disease severity, with more risks accepted when the patient's disease is more severe. The effectiveness of DMDs conditional on their position in a sequence and/or disease duration was discussed: there was consensus on some statements regarding this topic but these were accompanied by a high degree of uncertainty due to considerable knowledge gaps.

CONCLUSION

Useful insights into the medical decision-making process regarding treatment sequencing in RRMS were obtained. The knowledge gained has been used to validate the main modelling concepts and to further generate clinically meaningful results.

Multi-disciplinary Psychiatric Case Management Model in Hong Kong: Service Coverage and Risk Stratification

INTRODUCTION

Community mental health services in Hong Kong follow a multi-disciplinary case management model. We investigated whether at-risk patients received higher intensity care and whether risk stratification concorded between personalised care programmes and integrated community centres of mental wellness.

METHODS

Records of all patients in North Lantau and Mongkok districts who received case management services (from personalised care programmes and/or integrated community centres of mental wellness) between 1 April 2014 and 30 June 2015 were reviewed. Patients' levels of risk, demographic data, and clinical characteristics were analysed.

RESULTS

Identified at-risk patients received high-intensity care from personalised care programmes and integrated community centres of mental wellness. Case management was coordinated between the Hospital Authority and non-government organisations. However, risk stratification did not correlate with assessment rating scores of psychopathology or psychosocial functioning. Assessment rating scales appear unsuitable to provide any optimal cut-off scores for risk stratification.

CONCLUSIONS

Risk stratification should be a structured clinical judgement based on comprehensive and accurate information of protective and risk factors, rather than relying on cut-off scores of assessment rating scales.

Dedifferentiated endometrioid adenocarcinoma of the uterus: A case series and review of literature

•

Dedifferentiated endometrioid adenocarcinoma is a rare aggressive subtype of endometrial cancer.

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Patients tend to present at a later stage and have early recurrences.

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Proportion of DEAC in endometrial cancer may affect outcome.

•

Further research should focus on PD-L1 expression and the use immunotherapy.

Introduction Dedifferentiated endometrioid adenocarcinoma (DEAC) was first described in 2007. However, it has only been recognised as a distinct subtype of endometrioid adenocarcinoma in the last 1–2 years. DEAC is a more aggressive histological subtype and carries a poorer prognosis. Patients with DEAC tend to present with advanced disease compared the other endometrioid adenocarcinomas. Methodology The study is a retrospective review of patients with DEAC diagnosed in two institutions in Singapore between January 2012 and October 2017. Results 7 patients were diagnosed with DEAC. The mean age was 56.4 years. All patients presented with either abnormal uterine bleeding or post menopausal bleeding. Out of the 7 patients, one was diagnosed with Stage 2 disease, 5 were diagnosed with Stage 3 disease and 1 was diagnosed with Stage 4 disease. One patient had neoadjuvant chemotherapy, followed by surgery, and completion chemotherapy post surgery. The other 6 patients (87.5%) underwent primary debulking surgery. Out of these 6 patients, 5 patients had adjuvant chemotherapy post surgery and one patient had both adjuvant chemotherapy and radiotherapy. Lymphovascular invasion was found in 71.4% of the cases. Conclusion DEAC is a more aggressive histological subtype of endometrioid adenocarcinomas. Better awareness of this condition can lead to proper diagnosis and treatment.

The Landmark Series: Randomized Trials Examining Surgical Margins for Cutaneous Melanoma

Between 1980 and 2004, six randomized, controlled trials (RCTs) have been performed to evaluate the width of surgical margin excision for primary cutaneous melanoma and its influence on recurrence and survival. These trials have led to the current recommendation of not more than a 2-cm margin excision and have allowed reduced morbidity of surgery for primary melanoma. Long-term follow-up data has been published which has led to impactful knowledge of the natural history of this disease, yet controversy remains for 1- to 2-mm thickness melanomas. Interpretation of these trials must be done in light of them enrolling patients before the use of sentinel node biopsy and contemporary immunotherapy regimens. These RCTs as well as a contemporary, actively enrolling trial are summarized and discussed in this review.

Meta-analysis of completion lymph node dissection in sentinel lymph node-positive melanoma

BACKGROUND

The role of completion lymph node dissection (CLND) in patients with sentinel lymph node (SLN)-positive melanoma continues to be debated. This systematic review and meta-analysis evaluated survival and recurrence rate in these patients who underwent CLND, compared with observation.

METHODS

A comprehensive MEDLINE and Embase database search was performed for cohort studies and RCTs published between January 2000 and June 2017 that assessed the outcomes of CLND compared with observation in patients with SLN-positive melanoma. The primary outcome was survival and the secondary outcome was recurrence rate. Studies were assessed for quality using the Cochrane risk-of-bias tool for RCTs and Newcastle-Ottawa Scale for cohort studies. Pooled relative risk or hazard ratio with 95 per cent confidence intervals were calculated for each outcome. The extent of heterogeneity between studies was assessed with the I² test. The protocol was registered in PROSPERO (CRD42017070152).

RESULTS

Fifteen studies (13 cohort studies with 7868 patients and 2 RCTs with 2228 patients) were identified for qualitative synthesis. Thirteen studies remained for quantitative meta-analysis. Survival was similar in patients who underwent CLND and those who were observed (risk ratio (RR) for death 0·85, 95 per cent c.i. 0·71 to 1·02). The recurrence rate was also similar (RR 0·91, 0·79 to 1·05).

CONCLUSION

Patients with SLN-positive melanoma do not have a significant benefit in survival or recurrence rate if they undergo CLND rather than observation.

Pyrolysis of low density polyethylene waste in subcritical water optimized by response surface methodology

Pyrolysis of low density polyethylene (LDPE) waste from local waste separation company in subcritical water was conducted to investigate the effect of reaction time, temperature, as well as the mass ratio of water to polymer on the liquid yield. The data obtained from the study were used to optimize the liquid yield using response surface methodology. The range of reaction temperature used was 162-338°C, while the reaction time ranged from 37 min to 143 min, and the ratio of water to polymer ranged from 1.9 to 7.1. It was found that pyrolysis of LDPE waste in subcritical water produced hydrogen, methane, carbon monoxide and carbon dioxide, while the liquid product contained alkanes and alkenes with 10-50 carbons atoms, as well as heptadecanone, dichloroacetic acid and heptadecyl ester. The optimized conditions were 152.3°C, reaction time of 1.2 min and ratio of water solution to polymer of 32.7, with the optimum liquid yield of 13.6 wt% and gases yield of 2.6 wt%.

Twist-controlled resonant tunnelling in graphene/boron nitride/graphene heterostructures

Recent developments in the technology of van der Waals heterostructures made from two-dimensional atomic crystals have already led to the observation of new physical phenomena, such as the metal-insulator transition and Coulomb drag, and to the realization of functional devices, such as tunnel diodes, tunnel transistors and photovoltaic sensors. An unprecedented degree of control of the electronic properties is available not only by means of the selection of materials in the stack, but also through the additional fine-tuning achievable by adjusting the built-in strain and relative orientation of the component layers. Here we demonstrate how careful alignment of the crystallographic orientation of two graphene electrodes separated by a layer of hexagonal boron nitride in a transistor device can achieve resonant tunnelling with conservation of electron energy, momentum and, potentially, chirality. We show how the resonance peak and negative differential conductance in the device characteristics induce a tunable radiofrequency oscillatory current that has potential for future high-frequency technology.

Impermeable barrier films and protective coatings based on reduced graphene oxide

Flexible barrier films preventing permeation of gases and moistures are important for many industries ranging from food to medical and from chemical to electronic. From this perspective, graphene has recently attracted particular interest because its defect-free monolayers are impermeable to all atoms and molecules. However, it has been proved to be challenging to develop large-area defectless graphene films suitable for industrial use. Here we report barrier properties of multilayer graphitic films made by gentle chemical reduction of graphene oxide laminates with hydroiodic and ascorbic acids. They are found to be highly impermeable to all gases, liquids and aggressive chemicals including, for example, hydrofluoric acid. The exceptional barrier properties are attributed to a high degree of graphitization of the laminates and little structural damage during reduction. This work indicates a close prospect of graphene-based flexible and inert barriers and protective coatings, which can be of interest for numerous applications.

Neutrophil extracellular traps form predominantly during the organizing stage of human venous thromboembolism development

BACKGROUND

A growing health problem, venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT), requires refined diagnostic and therapeutic approaches. Neutrophils contribute to thrombus initiation and development in experimental DVT. Recent animal studies recognized neutrophil extracellular traps (NETs) as an important scaffold supporting thrombus stability. However, the hypothesis that human venous thrombi involve NETs has not undergone rigorous testing.

OBJECTIVE

To explore the cellular composition and the presence of NETs within human venous thrombi at different stages of development.

PATIENTS AND METHODS

We examined 16 thrombi obtained from 11 patients during surgery or at autopsy using histomorphological, immunohistochemical and immunofluorescence analyses.

RESULTS

We classified thrombus regions as unorganized, organizing and organized according to their morphological characteristics. We then evaluated them, focusing on neutrophil and platelet deposition as well as micro-vascularization of the thrombus body. We observed evidence of NET accumulation, including the presence of citrullinated histone H3 (H3Cit)-positive cells. NETs, defined as extracellular diffuse H3Cit areas associated with myeloperoxidase and DNA, localized predominantly during the phase of organization in human venous thrombi.

CONCLUSIONS

NETs are present in organizing thrombi in patients with VTE. They are associated with thrombus maturation in humans. Dissolution of NETs might thus facilitate thrombolysis. This finding provides new insights into the clinical development and pathology of thrombosis and provides new perspectives for therapeutic advances.

Pedometer-determined physical activity and body composition in Chinese working adults

PURPOSE

Overweight and obesity are prevalent public health problems in many developed and developing regions. Despite extensive documentation on the health benefits of physical activities, little is known about the level of physical activity in the Hong Kong Chinese population. Working adults, in particular, deserve primary attention because they account for the largest proportion of Hong Kong society. The purposes of this study were to investigate pedometer-determined physical activity and examine the associations between physical activity and body composition variables among Chinese working adults in Hong Kong.

DESIGN

This study adopted a descriptive cross-sectional design.

METHODS

A quota sample of 913 working adults from nine major occupational categories was recruited. Demographic characteristics and body composition parameters (weight, height, and waist and hip circumferences) were assessed. Body mass index and waist-to-hip ratio were then calculated. Physical activity was measured in terms of daily walking steps using a pedometer over 1 week. Participants were then categorized as "inactive,""somewhat active," or "regularly active." Descriptive and inferential statistics (analysis of variance, t test, and χ(2) test) were used appropriately.

FINDINGS

Of the 913 participants, 893 returned complete step count records. The completion rate was 97.8%. Participants on average walked 8,661 steps per day, suggesting a "somewhat active" populace. Significant differences were found between the group "regularly active" and "inactive" in most of the body composition parameters. However, a significant weak correlation was found between physical activity and body mass index (r= 0.12, p= .001). Such findings deserve further investigation.

CONCLUSIONS

The Chinese working adults in Hong Kong were found to be somewhat active in physical activity.

CLINICAL RELEVANCE

Findings pose implications for healthcare professionals who are responsible for health promotion in the Asian community setting. Leisure-type physical activity, such as walking, can be incorporated into daily routines.

P2-15-07: The Need for Additional Surgeries to Adequately Excise Early Breast Cancers May Have a Negative Impact on Local Recurrence

Background: Breast conservation surgery (BCS) is considered the standard of care for the treatment of early stage breast cancer (ESBC, AJCC stage 1 and 2). 20 to 50% of patients will require further surgery for positive or close margins. There is recent data suggesting that re-operation can have a negative impact on local and distant recurrences. Our aim is to examine the effects of multiple surgeries to obtain adequate margins on breast cancer recurrence, metastatic disease and survival.

Methods: We reviewed a prospectively maintained breast cancer database at the University Health Network and included all women who had BCS for their first diagnosis of ESBC between January 2004 and December 2007. Patients with neoadjuvant chemotherapy were excluded. We collected patient demographics, surgical pathology, adjuvant therapy and follow up outcome data, which included local recurrence, distant recurrence, cancer-specific survival and overall survival. Clinical and pathologic features were compared using chi-square analyses. Patients who had one lumpectomy were compared to those who had multiple surgeries by using Kaplan-Meier survival curves and log rank test.

Results: Of a total of 744 patients (8 patients had bilateral cancer) 577 (77.6%) had one lumpectomy only (Group 1). 167 (22.4%) patients required further surgery (group 2 = LR+LM+LRM): 83 (11.1%) had a re-excision (LR), 69 (9.3%) had mastectomy (LM) and 15 (2%) had a re-excision followed by a mastectomy (LRM). Thus, a total of 85 (11.4%) patients had mastectomy to achieve adequate margins. All clinicopathologic factors and adjuvant systemic treatments were similar between the two groups except for age and use of adjuvant radiotherapy, which was related to that fact that many of those in group 2 had mastectomy. We observed a difference in disease-free survival favoring patients with lumpectomy only (group 1–3.4% vs. group 2–8.1%, p= 0.01) but there was no difference in distant metastasis (4.5% vs. 5.6%, p=0.56), cancer-specific survival (97.6% vs. 95.6%, p=0.20) and overall survival (6.9% vs 6.3%, p= 0.76) at a median follow up of 4.54 years.

Conclusion: Despite having similar stage, grade, receptor status and adjuvant systemic therapies, having multiple surgeries for primary breast cancer appeared to be associated with decreased disease-free survival but had no difference in rates of distant metastatic disease, cancer-specific survival and overall survival.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-15-07.

Children with learning disabilities in the paediatric clinic, Hospital Tuanku Ja'afar Seremban: an overview

The aim of the study was to document the prevalence of learning disability among the children attending the Paediatric Clinic in Hospital Tuanku Ja'afar Seremban. The demographic distribution of these patients; the age of detection of the problem; the associated medical conditions and types of intervention received by these patients were documented. Patients who were between the ages of five to twelve years were included in the study. Learning disability was divided into three categories: speech and articulation problems, academic skills disorder and other categories which included developmental delay. Children with cerebral palsy were excluded from the study. Out of 1320 patients screened, 355 were found to have learning disorders. Majority were Malays, with the male to female ratio of 1.9:1. Most of the patients stayed in Seremban. The learning problem was most commonly detected at the age of 4 years and below. The commonest type of learning disorder was developmental delay, followed by academic skills disorder, speech and academic skills problems and speech disorders. Problems that were detected early were speech problems and developmental delay. Majority of the children had associated medical conditions. Most of the patients received some form of intervention but 11.3% did not attend any intervention program at all. A strategy should be formulated and implemented to help this group of children.

Cryptococcal osteomyelitis of the femur: a case report and review of literature

Fungal osteomyelitis is a rare opportunistic infection. It exhibits some clinical and radiological similarities to several other bone pathologies. A diagnostic delay may result in significant increase in morbidity. We report a case of a 37-year-old man with underlying hypogammaglobulinaemia presented with isolated cryptococcal osteomyelitis of the femur.

A new mathematical model for irradiance field prediction of upper-room ultraviolet germicidal systems

There has been an increasing interest in the use of upper-room ultraviolet germicidal irradiation (UVGI) system because of its proven disinfection effect for airborne microorganisms. To better design and explore further potential applications of UVGI systems, it is of critical importance to predict the spatial UV intensity in enclosures. In this paper, we developed a new mathematical model to predict spatial radiation intensity for upper-room ultraviolet germicidal irradiation systems. The detail geometries of the lamp and the reflector were removed and replaced by introducing a fictitious irradiation surface near louver slots. The view factor approach was applied to evaluate the UV irradiance in a three-dimensional space with different louver configurations. With this approach no detail meshing of the fixture is required and this leads to significant simplification of the entire systems from modeling perspectives. To validate the model, experiments were performed in a full-scale environmental controlled chamber in which one UVGI fixture was mounted on a sidewall. The UV irradiance was measured by a radiometer. The results predicted by the present model agree very well with the experimental measurements. Factors affect the accuracy of the model was also discussed.

Osteonecrosis of the jaw after oral bisphosphonate for osteoporosis

Bisphosphonates are a common treatment for osteoporosis. Osteonecrosis of the jaw has been associated with the use of bisphosphonates, usually when they have been used parenterally to treat malignancies. Cases associated with oral bisphosphonate as a treatment for osteoporosis are less frequent. We describe two patients exhibiting the clinical manifestations of bisphosphonate-associated osteonecrosis of the jaw. A brief review of the literature on the incidence, possible risk factors, and practice guidelines is also presented.

Animal-type melanoma: a clinical and histopathological study of 22 cases from a single institution

Background Animal-type melanoma is a rare distinct melanoma subtype, characterized by proliferation of heavily pigmented epithelioid and spindled melanocytes that resembles the heavily pigmented melanomas seen in grey horses. While animal-type melanoma is generally considered to be more indolent than conventional melanoma, only a limited number of cases have been reported and, as such, the clinical characteristics of animal-type melanoma are incompletely understood. Objectives To characterize the clinical and histopathological features of animal-type melanoma, and determine any features that may predict outcome. Patients/Methods Data was extracted from a prospectively collected melanoma database (1994-2008), and a retrospective pathology database (1991-2008) for all patients with a diagnosis of both equivocal (8) and unequivocal (14) malignant animal-type melanoma. We reviewed the clinical and histopathological features, including the sentinel lymph node biopsy (SLNB) status. Results A total of 22 patients were identified, with a median age of 35 years. The median Breslow depth was 2.22 mm. A SLNB was performed in 17 patients, eight (47%) were positive. Younger age was associated with: (i) animal-type melanoma with features equivocal for malignancy (median age of 7 vs. 48 years, P = 0.01), and (ii) a negative SLNB (median age 12 vs. 53 years, P = 0.03). Four patients with unequivocal animal-type melanoma developed recurrent metastatic disease, with one patient death. No patient with an equivocal animal-type melanoma or negative SLNB developed recurrent disease; however, this did not reach statistical significance (P = 0.13 and P = 0.09, respectively). Conclusions Animal-type melanoma has a propensity for regional lymphatic metastasis and is rarely capable of disseminated metastatic disease and death. Animal-type melanoma appears to exhibit a spectrum of biological behaviour, with young patient age associated with more indolent disease.

Increased frequency of isolated cleft palate in infants exposed to lamotrigine during pregnancy

BACKGROUND

Pregnancy registries for women taking anticonvulsant drugs have been developed to determine more efficiently the fetal risks of each drug. A total of 722 drug-exposed pregnancies are needed to identify a sevenfold increase in the rate of occurrence of a specific abnormality, such as spina bifida, with a frequency of 1 in 1,000.

METHODS

The infants with major malformations born to the 791 women who had taken lamotrigine as monotherapy and had enrolled in the North American AED Pregnancy Registry were identified. Medical records were obtained from the affected infants' doctors. A total of 107 of the 791 infants or pregnancies were excluded.

RESULTS

A total of 16 (2.3%) of 684 infants exposed to lamotrigine had major malformations that were identified at birth. Five infants (7.3/1,000) had oral clefts: isolated cleft palate (3), isolated cleft lip (1), and cleft lip and palate (1). The rate among the lamotrigine-exposed infants showed a 10.4-fold increase (95% CI: 4.3-24.9) in comparison to 206,224 unexposed infants surveyed at birth at Brigham and Women's Hospital in Boston, where the prevalence of isolated oral clefts was 0.7/1,000. A comparison was made also to 1,623 infants exposed to lamotrigine, as monotherapy, who had enrolled in five other registries. There were four infants with oral clefts: prevalence 2.5/1,000 (RR: 3.8, 95% CI: 1.4-10.0).

CONCLUSIONS

The infant exposed in the first trimester of pregnancy to the anticonvulsant drug lamotrigine has an increased risk to have an isolated cleft palate or cleft lip deformity.

Epidemiology and strain characterization of rotavirus diarrhea in Malaysia

OBJECTIVES

The objectives of the study were to describe the epidemiology and strain characterization of rotavirus (RV), to determine the proportion of hospitalizations for diarrhea attributable to RV among children under 5 years of age, and to estimate the disease burden of RV diarrhea in Malaysia.

METHODS

All children 0-59 months of age admitted for acute gastroenteritis to Kuala Lumpur Hospital (KLH) or Hospital Umum Sarawak (HUS) were surveyed. The periods of surveillance were from February 1, 2001 to April 30, 2003 in KLH and April 1, 2001 to March 31, 2003 for HUS.

RESULTS

The highest rate of RV-associated diarrhea was among children aged 6-17 months, accounting for 55% of RV-associated diarrhea. There was no seasonality observed in either hospital. P[8]G9 strains were predominant, accounting for 73% of all strains in both hospitals, 80% from KLH and 61% from HUS. There was no mortality.

CONCLUSIONS

RV was responsible for 38% of hospitalizations for diarrhea. It was most common in the 6-17 months age group. There was no seasonality observed for RV-associated diarrhea. The most prevalent strain of RV was P[8]G9. The estimated incidence of RV-associated diarrhea was 27 per 10000 population under the age of 5 years per year.

Deaths in children during an outbreak of hand, foot and mouth disease in Peninsular Malaysia--clinical and pathological characteristics

From July through December 1997, 11 previously healthy children in Peninsular Malaysia succumbed to an illness clinically characterised by an acute severe refractory left-ventricular failure, following a brief prodromal illness, in the midst of an outbreak of hand, foot and mouth disease (HFMD), similar to the reported experience in Sarawak and Taiwan. Retrospective reviews of the clinical features and results of laboratory, pathological and virological investigations of cases were conducted. The median age of the 11 case-patients was 31 months (range, 13 to 49 months); 6 were males. A brief prodromal illness of 3 days (range, 2 to 5 days) was characterised by fever (axillary temperature > 38 degrees C) (100%), oral ulcers (72%), extremity rashes (45%) and significant vomiting (55%). Upon hospitalisation, 7 of 11 case-patients had features suggestive of cardiogenic shock, while 4 of 11 case-patients developed shock during hospitalisation as evidenced by marked sustained tachycardia (heart rate > or = 180 beats per minute), poor peripheral pulses and peripheral perfusion, mottled extremities, pulmonary oedema (haemorrhagic pulmonary secretions in 8 of 11 cases during tracheal intubation, often precipitated by conservative crystalloid boluses, and radiographic evidence of acute pulmonary oedema in 5 of 7 cases) and markedly impaired left ventricular function on echocardiographic examination (7 of 7 cases). Three of 4 case-patients had aseptic meningitis while one case-patient also had an acute flaccid paraparesis. Despite supportive therapy, death occurred within a median of 13.4 hours following hospitalization. Post-mortem findings (all 8 specimens examined) consistently demonstrated brain-stem encephalitis with foci of neuronal necrosis and micro-abscesses. None of the 11 specimens examined revealed histological evidence of myocarditis. Enterovirus 71 (EV71) was detected in 10 of 11 case-patients, many (7) from various sterile tissue sites (5 from central nervous tissues). No other viruses were isolated or identified. Clinical features and pathological studies closely paralleled the reported experience in Sarawak and Taiwan. The uniform necropsy findings of necrotizing brain-stem encephalitis coupled with essentially normal myocardial histology, in concert with the concurrent and consistent detection of EV71 points to a primary EV71 encephalitis; as yet unclear neurogenic mechanisms may account for the cardiovascular manifestations.

Interaction of glass-ionomer cements with moist dentin

Glass-ionomer cements (GICs) are regarded as aqueous gels made up of polyalkenoic acid salts containing ion-leachable glass fillers. The consequence of water permeation across the GIC-dentin interface is unknown. This study used SEM, field-emission/environmental SEM (FE-ESEM), and TEM to examine the ultrastructure of GIC-bonded moist dentin. Dentin surfaces bonded with 6 auto-cured GICs were examined along the fractured GIC-dentin interfaces. Additional specimens fractured 3 mm away from the interfaces were used as controls. SEM revealed spherical bodies along GIC-dentin interfaces that resembled hollow eggshells. FE-SEM depicted similar bodies with additional solid cores. Energy-dispersive x-ray analysis and TEM showed that the spherical bodies consisted of a silicon-rich GIC phase that was absent from the air-voids in the controls. The GIC inclusions near dentin surfaces result from a continuation of the GI reaction, within air-voids of the original polyalkenoate matrix, that occurred upon water diffusion from moist dentin.

Small area variations of cancer mortality in Hong Kong--the roles of health care and socio-economic status

Variations of cancer incidence and cancer mortality across small areas in Hong Kong were explored and attempt made to link them to socio-economic differences. The entire Hong Kong population during the period 1984-88 was divided into 65 small areas. The geographic distributions of incidence and mortality for ten most frequent sites of cancers (6 male and 4 female) were analyzed by separating the systematic variance from the random variance. A Poisson regression model was fitted for each cancer using the standardized incidence ratio (SIR) as a covariate for mortality. The geographic variations in SIR for the individual cancers were, in turn, analyzed similarly using a socio-economic score as the covariate. We found a statistically significant systematic variance in mortality for all six male cancers and three of the four female cancers studied. More than 50% of the systematic variance of mortality for nine cancers could be explained by the geographic variations in incidence, suggesting that other factors, like the provision and/or outcomes of health care services, played a minor role. There were statistically significant systematic variances in SIR for all male and female cancers. The socio-economic score accounted for over 50% of the systematic variance for three cancer sites. This study illustrated an approach to explore underlying explanations for the geographic variations of disease incidence and mortality. As more aggregate exposure data become available at the small area level, this type of ecological analysis would help in delineating the contributions of various factors and guide investigators in their search for the etiology background of diseases.

Modelling death rates for carriers of hepatitis B

Hepatitis B carriers who acquired the infection perinatally die from hepatocellular carcinoma (HCC) and cirrhosis at high rates. Published cohort studies are largely limited to males and are too small to estimate the age-specific risk of death. We therefore used routinely collected Hong Kong data to estimate the risks. Deaths were partitioned between carriers and non-carriers, then current life table calculations determined life expectancy and probability of dying from HCC or cirrhosis. HCC is the dominant cause of death for male carriers in middle adulthood with a lifetime risk of 27% for HCC compared to 4% for females. Predicted life expectancy is 72 years for male carriers, compared to 79 years for non-carriers. Female carriers have a life expectancy of 81 years and non-carriers 83 years. This model probably applies to all southern Chinese populations and emigrants with similar life history, and other populations that acquired infection early in life.

p53 gene transfer does not enhance E2F-1-mediated apoptosis in human colon cancer cells

E2F-1 and p53 are sequence specific transcription factors that are intimately involved in the regulation of the cell cycle. In addition to their role in cell cycle control, both E2F-1 and p53 have been identified as tumor suppressors and mediators of apoptosis. We have shown previously that adenoviral-mediated E2F-1 overexpression induces efficient apoptosis in colon adenocarcinoma cells. Previous reports have suggested that E2F-1 and p53 cooperate to mediate apoptosis and therefore, in this study, we examined the efficacy of combination gene therapy using adenovirus vectors expressing E2F-1 and p53 in human colon adenocarcinoma cell lines, HT-29 and SW620 (both mutant p53). Cells were treated by mock infection or infection with adenoviral vectors expressing b-galactosidase (LacZ), E2F-1, p53 or a combination of E2F-1 and p53. IC25 concentrations of each virus were estimated and used for each treatment in order to detect any synergistic or cooperative effects on tumor cell death in the combination therapy. By 5 days post infection, E2F-1-overexpressing cells exhibited growth inhibition and approximately 40-50% cell death in both cell lines. Co-expression of p53 with E2F-1 abrogated E2F-1-mediated growth inhibition and cell death. Cell cycle analysis revealed that overexpression of E2F-1 resulted in an accumulation of cells in G2/M phase, while overexpression of p53 resulted in a G1 phase accumulation. However, co-expression of E2F-1 and p53 counteracted each other as fewer cells accumulated in G1 and G2/M when compared to either p53 or E2F-1 alone. Furthermore, co-expression of p53 with E2F-1 resulted in decreased levels of E2F-1 protein expression. Mechanistically, upregulation of the CDK inhibitory protein, p21(WAF1/CIP1), was demonstrated in HT-29 cells following overexpression of either E2F-1, p53 or the combination E2F-1/p53 therapy. However, in SW620 cells, only the cells infected with Ad-p53 alone or in combination resulted in upregulation of p21(WAF1/CIP1). These results suggest that p53 and p21(WAF1/CIP1) may cooperate to inhibit the expression and activity of E2F-1. In conclusion, combination adenoviral vector-mediated E2F-1 and p53 gene transfer was not therapeutically advantageous in this in vitro model of human colon adenocarcinoma.

Development and characterization of a series of soluble tetrameric and monomeric streptavidin muteins with differential biotin binding affinities

The strong biotin-streptavidin interaction limits the application of streptavidin as a reversible affinity matrix for purification of biotinylated biomolecules. To address this concern, a series of single, double, and triple streptavidin muteins with different affinities to biotin were designed. The strategy involves mutating one to three strategically positioned residues (Ser-45, Thr-90, and Asp-128) that interact with biotin and other framework structure-maintaining residues of streptavidin. The muteins were produced in soluble forms via secretion from Bacillus subtilis. The impact of individual residues on the overall structure of streptavidin is reflected by the formation of monomeric streptavidin to different extents. Of the three targeted residues, Asp-128 has the most dramatic effect (Asp-128 > Thr-90 > Ser-45). Conversion of all three targeted residues to alanine results in a soluble biotin binding mutein that exists 100% in the monomeric state. Both wild-type and mutated (monomeric and tetrameric) streptavidin proteins were purified, and their kinetic parameters (on- and off-rates) were determined using a BIAcore biosensor with biotin-conjugated bovine serum albumin immobilized to the sensor chip. This series of muteins shows a wide spectrum of affinity toward biotin (K(d) from 10(-6) to 10(-11) m). Some of them have the potential to serve as reversible biotin binding agents.

Radiofrequency ablation for unresectable hepatic tumors

BACKGROUND

Radiofrequency ablation (RFA) is a relatively new treatment for unresectable hepatic tumors. The purpose of this analysis was to examine the frequency of complications and local recurrence associated with RFA.

METHODS

Patients who underwent RFA of hepatic tumors with curative intent were included in this study. At laparotomy, RFA was performed using intraoperative ultrasound guidance. Computed tomography scans were obtained in the immediate postoperative period and every 3 to 6 months thereafter.

RESULTS

Forty patients underwent RFA for 122 hepatic tumors. Thirty-one patients had metastatic lesions from colorectal cancer; 9 had other liver tumors. Complications occurred in 8 patients. With 9.5 months median follow-up, 6 patients had local recurrence of their ablated tumors.

CONCLUSIONS

Our initial experience shows that RFA can effectively eradicate unresectable hepatic tumors. The rate and severity of complications appear acceptable. However, further study is necessary to assess long-term recurrence rates and effect on overall survival.

Utility of intraoperative frozen section analysis of sentinel lymph nodes in breast cancer

BACKGROUND

Intraoperative frozen section pathologic analysis of sentinel lymph node (SLN) may guide immediate (single-stage) completion axillary dissection for patients with nodal metastases.

METHODS

The results of 203 consecutive patients undergoing SLN biopsy who had intraoperative pathology consultation between January 1998 and September 2000 were reviewed. SLN were analyzed by standard frozen section procedures. Final pathologic analysis included hematoxylin and eosin (H&E) staining of serial sections at 2-mm intervals.

RESULTS

Frozen section analysis correctly identified a positive or negative result in 185 of 203 cases (overall accuracy 91%). In 17 of 53 cases, the SLNs were negative for tumor by frozen section, but positive on permanent section analysis (sensitivity 68%). The mean size of the nodal metastases was 6.2 mm and 1.5 mm in patients found to have true positive and false negative results, respectively (P <0.003). A single false positive SLN is reported.

CONCLUSIONS

Two thirds of the patients were spared the need for reoperative axillary lymphadenectomy.

The use of cytokeratin staining in sentinel lymph node biopsy for breast cancer

BACKGROUND

Controversy exists regarding the routine use of cytokeratin immunohistochemistry (IHC) in the histopathologic examination of breast cancer sentinel lymph nodes (SLN) because the clinical significance of micrometastases detected by IHC is unclear. This analysis was performed to determine the frequency of IHC-detected micrometastases.

METHODS

All patients underwent SLN biopsy, followed by completion axillary dissection. This analysis included patients who had SLN evaluated by IHC. SLN were examined by hematoxylin and eosin (H&E) stain at 2-mm intervals, with IHC in 2 sections. The axillary dissection specimen was evaluated by routine H&E staining.

RESULTS

IHC was performed in SLNs from 973 patients. Of the 869 patients with negative nodes by H&E, 58 (6.7%) were "upstaged" by IHC. In 6 of 58 patients (10.3%) who had IHC-only positive SLN, nodal metastases were found in the axillary dissection specimen.

CONCLUSIONS

IHC resulted in upstaging of 6.7% of patients who had negative SLN on H&E staining. These patients had a 10.3% risk of residual axillary nodal metastases. However, the clinical significance of IHC-only positive SLN requires further study.

Reliable lymphatic drainage to axillary sentinel lymph nodes regardless of tumor location within the breast

BACKGROUND

This analysis was performed in order to determine whether primary tumor location in breast cancer affects the axillary sentinel lymph node (SLN) identification (ID) rate, the false negative (FN) rate, incidence of axillary nodal metastases, or the number of SLN identified.

METHODS

In this prospective multi-institutional study, SLN biopsy was performed on clinical stage T1-2, N0 breast cancer patients using blue dye alone or in combination with radioactive colloid, followed by completion axillary LN dissection.

RESULTS

Central tumor location was associated with an improved FN rate, which may be related to reliable drainage from the subareolar lymphatic plexus. Tumor location did not significantly affect the SLN ID rate or the mean number of SLN identified. Medial tumor location was associated with a decreased rate of axillary nodal metastasis.

CONCLUSIONS

Breast cancers drain reliably to the axillary lymph nodes regardless of tumor location within the breast.

Defining the optimal surgeon experience for breast cancer sentinel lymph node biopsy: a model for implementation of new surgical techniques

OBJECTIVE

To determine the optimal experience required to minimize the false-negative rate of sentinel lymph node (SLN) biopsy for breast cancer.

SUMMARY BACKGROUND DATA

Before abandoning routine axillary dissection in favor of SLN biopsy for breast cancer, each surgeon and institution must document acceptable SLN identification and false-negative rates. Although some studies have examined the impact of individual surgeon experience on the SLN identification rate, minimal data exist to determine the optimal experience required to minimize the more crucial false-negative rate.

METHODS

Analysis was performed of a large prospective multiinstitutional study involving 226 surgeons. SLN biopsy was performed using blue dye, radioactive colloid, or both. SLN biopsy was performed with completion axillary LN dissection in all patients. The impact of surgeon experience on the SLN identification and false-negative rates was examined. Logistic regression analysis was performed to evaluate independent factors in addition to surgeon experience associated with these outcomes.

RESULTS

A total of 2,148 patients were enrolled in the study. Improvement in the SLN identification and false-negative rates was found after 20 cases had been performed. Multivariate analysis revealed that patient age, nonpalpable tumors, and injection of blue dye alone for SLN biopsy were independently associated with decreased SLN identification rates, whereas upper outer quadrant tumor location was the only factor associated with an increased false-negative rate.

CONCLUSIONS

Surgeons should perform at least 20 SLN cases with acceptable results before abandoning routine axillary dissection. This study provides a model for surgeon training and experience that may be applicable to the implementation of other new surgical technologies.

Roles of glucitol in the GutR-mediated transcription activation process in Bacillus subtilis: glucitol induces GutR to change its conformation and to bind ATP

GutR is a 95-kDa glucitol-dependent transcription activator that mediates the expression of the Bacillus subtilis glucitol operon. Glucitol allows GutR to bind tightly to its binding site located upstream of the gut promoter. In this study, a second functional role of glucitol is identified. Glucitol induces GutR to change its conformation and triggers GutR to bind ATP efficiently. After sequential binding of glucitol and ATP to GutR, GutR adopts a new conformation by forming a compact structure that is resistant to trypsin digestion. Under this condition, the ATP.glucitiol.GutR complex can dissociate slowly from the gutR-binding site (t(12) = 274 min). Interestingly, if ATP in the ATP.glucitiol.GutR complex is replaced by ADP, GutR adopts another conformation and can dissociate from the gutR-binding site even faster (t(12) = 82 min). In all these GutR-DNA binding studies in the presence of different ligands (glucitol, ATP, or ADP), only the off-rate is affected. The vital role of ATP in the GutR-mediated transcription activation process is reflected by the poor transcription from the gut promoter with GutR(D285A) which has a mutation in the motif B of the putative ATP-binding site. A working model for this transcription activation process is presented.

Factors that predict the presence of sentinel lymph node metastasis in patients with melanoma

BACKGROUND

This analysis was performed to identify prognostic factors that are predictive of sentinel lymph node (SLN) metastasis in melanoma.

METHODS

Analysis was performed of a multi-institutional, prospective, randomized trial of SLN biopsy for melanoma. Eligibility criteria included age 18 to 70 years, Breslow thickness of 1.0 mm or more, and clinically negative regional lymph nodes. SLNs were evaluated by serial sectioning and immunohistochemistry for S100. Univariate chi-square and multivariate logistic regression analyses were performed to assess factors predictive of the presence of a positive SLN. Probability values of less than.05 were considered significant.

RESULTS

SLNs were identified in 99.7% of patients. A total of 1058 patients were evaluated; 961 patients had complete data and were included in the statistical analysis. SLNs were positive for tumor in 208 of 961 patients (22%). Breslow thickness, Clark level, ulceration, and patient age were factors that were found to be independently predictive of the presence of SLN metastasis.

CONCLUSIONS

Increasing Breslow thickness, Clark level of more than III, the presence of ulceration, and patient age of 60 years or less are the most important independent prognostic factors associated with the finding of positive SLN in patients with melanoma.

Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of nonsentinel nodes following completion lymphadenectomy for melanoma

INTRODUCTION

Most melanoma patients with sentinel lymph nodes (SLN) that are histologically positive for metastasis have no additional positive lymph nodes found upon completion lymph node dissection (CLND). Therefore, it has been suggested that CLND may not be required for all patients with positive SLN. This study was undertaken to determine the frequency with which nonsentinel nodes contain melanoma cells detected by RT-PCR.

METHODS

Negative control lymph nodes were obtained from patients with breast and colon cancer. Positive control lymph nodes contained histologic evidence of melanoma. Nonsentinel nodes were harvested from melanoma patients undergoing CLND for a positive SLN. RT-PCR analysis for melanoma markers tyrosinase, gp100, MART-1, and MAGE-3 was performed, with Southern blot detection. The RT-PCR test was considered positive for the presence of melanoma cells if tyrosinase and at least one other marker were detected above background levels.

RESULTS

RT-PCR analysis detected the presence of melanoma cells in 0/100 (0%) of negative control lymph nodes and 28/29 (97%) of positive control lymph nodes. A total of 117 histologically negative nonsentinel nodes from 13 patients who underwent CLND for positive SLN were evaluated. RT-PCR analysis was positive in 18/117 histologically negative nonsentinel nodes (15%) from 7/13 patients (54%).

CONCLUSION

RT-PCR analysis suggests that when the SLN contains histologic evidence of melanoma, the remaining nodes in that basin are at risk for metastatic disease, despite the fact that these nonsentinel nodes are infrequently histologically positive.

Dermal injection of radioactive colloid is superior to peritumoral injection for breast cancer sentinel lymph node biopsy: results of a multiinstitutional study

OBJECTIVE

To determine the optimal radioactive colloid injection technique for sentinel lymph node (SLN) biopsy for breast cancer.

SUMMARY BACKGROUND DATA

The optimal radioactive colloid injection technique for breast cancer SLN biopsy has not yet been defined. Peritumoral injection of radioactive colloid has been used in most studies. Although dermal injection of radioactive colloid has been proposed, no published data exist to establish the false-negative rate associated with this technique.

METHODS

The University of Louisville Breast Cancer Sentinel Lymph Node Study is a multiinstitutional study involving 229 surgeons. Patients with clinical stage T1-2, N0 breast cancer were eligible for the study. All patients underwent SLN biopsy, followed by level I/II axillary dissection. Peritumoral, subdermal, or dermal injection of radioactive colloid was performed at the discretion of the operating surgeon. Peritumoral injection of isosulfan blue dye was performed concomitantly in most patients. The SLN identification rates and false-negative rates were compared. The ratios of the transcutaneous and ex vivo radioactive SLN count to the final background count were calculated as a measure of the relative degree of radioactivity of the nodes. One-way analysis of variance and chi-square tests were used for statistical analysis.

RESULTS

A total of 2,206 patients were enrolled. Peritumoral, subdermal, or dermal injection of radioactive colloid was performed in 1,074, 297, and 511 patients, respectively. Most of the patients (94%) who underwent radioactive colloid injection also received peritumoral blue dye injection. The SLN identification rate was improved by the use of dermal injection compared with subdermal or peritumoral injection of radioactive colloid. The false-negative rates were 9.5%, 7.8%, and 6.5% (not significant) for peritumoral, subdermal, and dermal injection techniques, respectively. The relative degree of radioactivity of the SLN was five- to sevenfold higher with the dermal injection technique compared with peritumoral injection.

CONCLUSIONS

Dermal injection of radioactive colloid significantly improves the SLN identification rate compared with peritumoral or subdermal injection. The false-negative rate is also minimized by the use of dermal injection. Dermal injection also is associated with SLNs that are five- to sevenfold more radioactive than with peritumoral injection, which simplifies SLN localization and may shorten the learning curve.

Accuracy of sentinel lymph node biopsy for patients with T2 and T3 breast cancers

Although numerous studies have demonstrated that sentinel lymph node (SLN) biopsy can accurately determine the axillary nodal status for early breast cancer some studies have suggested that SLN biopsy may be less reliable for tumors >2 cm in size. This analysis was performed to determine whether tumor size affects the accuracy of SLN biopsy. The University of Louisville Breast Cancer Sentinel Lymph Node Study is a prospective multi-institutional study involving 226 surgeons. The study was approved by the Institutional Review Board of each institution, and informed consent was obtained from all patients. Patients with clinical stage T1-2 N0 breast cancer were eligible for the study. Some patients with T3 tumors were included because they were clinically staged as T2 but on final pathology were found to have tumors >5 cm. This analysis includes 2148 patients who were enrolled from August 1997 through October 2000. All patients underwent SLN biopsy using a combination of radioactive colloid and blue dye injection followed by completion Level I/II axillary dissection. Statistical comparison was performed by chi-square analysis. The SLN identification rate, false negative rate, and overall accuracy of SLN biopsy were not significantly different among tumor stages T1, T2, and T3. We conclude that SLN biopsy is no less accurate for T2-3 breast cancers compared with T1 tumors.