Assessment of Preanalytical Cerebrospinal Fluid Handling and Storage Factors on Measurement of Aβ1-42, Aβ1-40, and pTau181 Using an Automated Chemiluminescent Platform

BACKGROUND

Standardizing cerebrospinal fluid (CSF) laboratory protocols will improve the reliability and availability of clinical biomarker testing required for prescription of novel Alzheimer disease (AD) therapies. This study evaluated several preanalytical handling and storage factors common to β-amyloid1-42 (Aβ1-42), β-amyloid1-40 (Aβ1-40), and phosphorylated tau (pTau181) concentrations including storage at different temperatures, extended cap contact, various mixing methods, and multiple freeze-thaw cycles.

METHODS

Aβ1-42, Aβ1-40, and pTau181 concentrations were measured using LUMIPULSE G1200 automated assays. Samples were collected in polypropylene tubes of various volumes. Sample cap-contact was evaluated by storing samples in upright and inverted positions at either 4°C for 1 week or -80°C for 1 month. To assess mixing methods, samples were freeze-thawed and mixed by inversion, vortex, horizontal roller, or unmixed prior to assay sampling. The impact of successive freeze-thaw cycles was assessed through freezing, thawing, and analyzing CSF samples.

RESULTS

Short-term storage at 4°C did not affect Aβ1-42, Aβ1-40, or pTau181 measurements in any tube type. Tube cap contact affected Aβ1-42 in 2.5 mL tubes and pTau181 levels in 10 mL tubes. No difference was observed between mixing methods. After 4 freeze-thaw cycles, Aβ1-42 significantly decreased but Aβ1-40 remained unchanged. Utilizing the Aβ1-42/Aβ1-40 ratio, Aβ1-42 values normalized, maintaining ratio values within ±5% of baseline measurements.

CONCLUSIONS

Storage of CSF at 4°C for 1 week or -80°C for 1 month did not significantly affect Aβ1-42, Aβ1-40, pTau181, or associated ratio measurements. Tube cap-contact impacted pTau181 and pTau181/Aβ1-42 values in larger tubes. Mixing methods are equivalent. The Aβ1-42/Aβ1-40 ratio compensates for freeze-thaw variability up to 4 cycles.

Delayed skeletal development and IGF-1 deficiency in a mouse model of lysinuric protein intolerance

SLC7A7 deficiency, or lysinuric protein intolerance (LPI), causes loss of function of the y+LAT1 transporter critical for efflux of arginine, lysine and ornithine in certain cells. LPI is characterized by urea cycle dysfunction, renal disease, immune dysregulation, growth failure, delayed bone age and osteoporosis. We previously reported that Slc7a7 knockout mice (C57BL/6×129/SvEv F2) recapitulate LPI phenotypes, including growth failure. Our main objective in this study was to characterize the skeletal phenotype in these mice. Compared to wild-type littermates, juvenile Slc7a7 knockout mice demonstrated 70% lower body weights, 87% lower plasma IGF-1 concentrations and delayed skeletal development. Because poor survival prevents evaluation of mature knockout mice, we generated a conditional Slc7a7 deletion in mature osteoblasts or mesenchymal cells of the osteo-chondroprogenitor lineage, but no differences in bone architecture were observed. Overall, global Slc7a7 deficiency caused growth failure with low plasma IGF-1 concentrations and delayed skeletal development, but Slc7a7 deficiency in the osteoblastic lineage was not a major contributor to these phenotypes. Future studies utilizing additional tissue-specific Slc7a7 knockout models may help dissect cell-autonomous and non-cell-autonomous mechanisms underlying phenotypes in LPI.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

The nature effect in motion: visual exposure to environmental scenes impacts cognitive load and human gait kinematics

Prolonged exposure to urban environments requires higher cognitive processing resources than exposure to nature environments, even if only visual cues are available. Here, we explored the moment-to-moment impact of environment type on visual cognitive processing load, measuring gait kinematics and reaction times. In Experiment 1, participants (n = 20) walked toward nature and urban images projected in front of them, one image per walk, and rated each image for visual discomfort. Gait speed and step length decreased for exposure to urban as compared with nature scenes in line with gait changes observed during verbal cognitive load tasks. We teased apart factors that might contribute to cognitive load: image statistics and visual discomfort. Gait changes correlated with subjective ratings of visual discomfort and their interaction with the environment but not with low-level image statistics. In Experiment 2, participants (n = 45) performed a classic shape discrimination task with the same environmental scenes serving as task-irrelevant distractors. Shape discrimination was slower when urban scenes were presented, suggesting that it is harder to disengage attention from urban than from nature scenes. This provides converging evidence that increased cognitive demands posed by exposure to urban scenes can be measured with gait kinematics and reaction times even for short exposure times.

Healthcare utilisation in the last year of life in internal medicine, young-old versus old-old

Background

With increasing cost of healthcare in our aging society, a consistent pain point is that of end-of-life care. It is particularly difficult to prognosticate in non-cancer patients, leading to more healthcare utilisation without improving quality of life. Additionally, older adults do not age homogenously. Hence, we seek to characterise healthcare utilisation in young-old and old-old at the end-of-life.

Methods

We conducted a single-site retrospective review of decedents under department of Advanced Internal Medicine (AIM) over a year. Young-old is defined as 65–79 years; old-old as 80 years and above. Data collected was demographic characteristics; clinical data including Charlson Comorbidity Index (CCI), FRAIL-NH and advance care planning (ACP); healthcare utilisation including days spent in hospital, hospital admissions, length of stay of terminal admission and clinic visits; and quality of end-of-life care including investigations and symptomatic control. Documentation was individually reviewed for quality of communication.

Results

One hundred eighty-nine older adult decedents. Old-old decedents were mostly females (63% vs. 42%, p = 0.004), higher CCI scores (7.7 vs 6.6, p = 0.007), similarly frail with lower polypharmacy (62.9% vs 71.9%, p = 0.01). ACP uptake was low in both, old-old 15.9% vs. young-old 17.5%. Poor prognosis was conveyed to family, though conversation did not result in moderating extent of care.

Old-old had less healthcare utilisation. Adjusting for sex, multimorbidity and frailty, old-old decedents had 7.3 ± 3.5 less hospital days in their final year. Further adjusting for cognition and residence, old-old had 0.5 ± 0.3 less hospital admissions. When accounted for home care services, old-old spent 2.7 ± 0.8 less hospital days in their last admission.

Conclusion

There was high healthcare utilisation in older adults, but especially young-old. Enhanced education and goal-setting are needed in the acute care setting. ACP needs to be reinforced in acute care with further research to evaluate if it reduces unnecessary utilisation at end-of-life.

WITHDRAWN: Can Traditional Chinese Medicine provide insights into controlling the COVID-19 pandemic: Serpentinization-induced lithospheric long-wavelength magnetic anomalies in Proterozoic bedrocks in a weakened geomagnetic field mediate the aberrant transformation of biogenic molecules in COVID-19 via magnetic catalysis

This article has been withdrawn at the request of the authors and the editors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Development of humanized mouse and rat models with full-thickness human skin and autologous immune cells

The human skin is a significant barrier for protection against pathogen transmission. Rodent models used to investigate human-specific pathogens that target the skin are generated by introducing human skin grafts to immunocompromised rodent strains. Infection-induced immunopathogenesis has been separately studied in humanized rodent models developed with human lymphoid tissue and hematopoietic stem cell transplants. Successful co-engraftment of human skin, autologous lymphoid tissues, and autologous immune cells in a rodent model has not yet been achieved, though it could provide a means of studying the human immune response to infection in the human skin. Here, we introduce the human Skin and Immune System (hSIS)-humanized NOD-scid IL2Rγ^null (NSG) mouse and Sprague–Dawley-Rag2^tm2hera Il2rγ^tm1hera (SRG) rat models, co-engrafted with human full-thickness fetal skin, autologous fetal lymphoid tissues, and autologous fetal liver-derived hematopoietic stem cells. hSIS-humanized rodents demonstrate the development of human full-thickness skin, along with autologous lymphoid tissues, and autologous immune cells. These models also support human skin infection following intradermal inoculation with community-associated methicillin-resistant Staphylococcus aureus. The co-engraftment of these human skin and immune system components into a single humanized rodent model could provide a platform for studying human skin infections.

SAT0445 TRABECULAR BONE SCORE IMPROVES FRACTURE RISK STRATIFICATION IN PATIENTS WITH REDUCED BONE MINERAL DENSITY

Background:

Trabecular bone score (TBS) is a textural index of bone microarchitecture and has been found to be related to 3D bone structure. A number of cohort studies have demonstrated the value of TBS as an independent fracture risk in clinical trials. Yet, very little is known about the performance and clinical value of TBS in real life practice.

Objectives:

To investigate the sensitivity and specificity of TBS in identifying prevalent fractures when compared with bone mineral density (BMD) measured by DXA. To evaluate the added value of TBS in fracture risk prediction above that obtained from DXA.

Methods:

Consecutive patients aged ≥ 18 with BMI 15-37 attnding a DXA plus TBS assessment were considered eligible. Sensitivity, specificity, and area under the curve (AUC) for prevalent major osteoporotic fracture (MOF) and clinical vertebral fractures (VF) were assessed for the following parameters: BMD lowest T-score ≤-2.5 (neck of femur, total hip, or spine), TBS T-score ≤-2.5, and either TBS or BMD T-score ≤-2.5. BMD categories (normal, osteopenia, and osteoporosis) were stratified by TBS T-score: normal (T-score ≥-1), moderate (-1≥T-score≥-2.5), and degraded TBS (T-score ≤-2.5) resulting in 9 risk groups. Odds ratios were calculated for all risk categories and fracture prevalence was compared between the best and worst TBS strata at each BMD level using chi-square test.

Results:

540 patients (87% females, 68.1 ± 11.6 years) were included. 238 (44%) had MOF including 81 (15%) clinical VF. For MOF, BMD had higher sensitivity (49.6% vs 30.7%), lower specificity (68.2% vs 82.1%), and similar AUC (0.59 vs 0.56) versus TBS. For VF, the sensitivity, specificity and AUC for BMD were 60%, 64%, and 0.62 respectively versus 42%, 79.7%, and 0.61 for TBS. Combining TBS and BMD (either T-score ≤ -2.5) increased the sensitivity to 63% for MOF and 75.3% for VF without affecting AUC (0.6 and 0.64 respectively). Patients with osteoporosis and degraded TBS had the highest OR of 2.65 for MOF and 3.8 for VF. The fracture risk increased at the same level of BMD when TBS was degraded. Numerically, the risk of MOF increased steadily from strata 1 to 9 and was statistically significant for osteoporosis with degraded TBS and osteoporosis with moderate TBS. When both TBS and BMD were normal, the risk of fracture was significantly reduced. In the osteopenia and osteoporosis BMD categories, patients with degraded TBS had significantly higher prevalence of fracture compared to those with normal TBS in the same BMD category.

Conclusion:

Fracture risk stratification can be improved when TBS is added to BMD. The sensitivity of predicting fracture may also improve when TBS and BMD are combined. Patients with both normal TBS and BMD have the lowest fracture risk, whereas those with degraded TBS and osteoporosis have the highest risk of fracture and should be targeted for early or more aggressive treatment.

References:

[1]Hans D et al. J Bone Miner Res. 2011;26(11).

[2]McCloskey EV et al. Calcif Tissue Int. 2015;96(6).

Table 1.

Prevalence and risk of MOF and VF according to BMD stratified by TBS T-score

Patients within categoryNumber of MOFOR for MOFNumber of VFOR for VFNormal BMD & TBS497 (14.3%)0.19(0.08-0.43)*00.83(0.80-.87)*Normal BMD moderate TBS195 (26.3%)0.44(0.16-1.24)2 (10.5%)0.66(0.15-2.9)Normal BMD degraded TBS72 (28.6%)0.50(0.1-2.6)1 (14.3%)0.94(0.11-7.9)Osteopenia normal TBS9633 (34.4%)0.61(0.39-0.97)7 (7.3%)0.39(0.18-0.88)*Osteopenia moderate TBS9843 (43.9%)0.99(0.64-1.54)11 (11.2%)0.67(0.34-1.32)Osteopenia degraded TBS5730 (52.6%)1.47(.085-2.55)11 (19.3%)1.41(0.7-2.86)Osteoporosis normal TBS3918 (46.2%)1.1(0.57-2.1)6 (15.4%)1(0.42-2.6)Osteoporosis moderate TBS11259 (52.7%)1.55(1.02-2.35)*21 (18.8%)1.42(0.82-2.45)Osteoporosis degraded TBS6341 (65.1%)2.65(1.53-4.59)*22 (34.9%)3.8(2.12-6.83)*Total54023881

Acknowledgments:

Bone density team, Robert Jones and Agnes Hunt Orthopaedic Hospital

Disclosure of Interests:

None declared

SAT0479 IMPACT OF TRABECULAR BONE SCORE ON INTERVENTION THRESHOLD FOR BONE SPARING THERAPY IN PATIENTS REFERRED FOR BONE MINERAL DENSITY

Background:

Trabecular bone score (TBS) is an index of skeletal quality that has been validated as an independent risk factor for fracture and incorporated into fracture risk assessment (FRAX). TBS provides information on bone microarchitecture not captured from standard bone mineral density (BMD) measured by dual energy X-ray absorptiometry (DXA). Nonetheless, the clinical implications of using TBS in routine practice are not yet fully understood and warrant further evaluation.

Objectives:

To determine whether lumbar TBS can have an impact on clinician’s treatment threshold derived from DXA and clinical risk factors: does the addition of TBS to DXA measurements make the clinician more or less likely to recommend bone sparing therapy?

Methods:

A cross-sectional study at a tertiary metabolic bone centre in the West Midlands region of England. Three expert metabolic bone physicians, two rheumatologists and one elderly care, assessed consecutive patients referred for a DXA scan ± clinic review and provided treatment recommendations with and without TBS. Patients ≥ 18 years old with BMI of 15-37 who were not on bone sparing therapy were considered eligible. TBS was defined according to T-score as normal (T-score ≥ -1), moderate (-1 > T-score ≥ -2.5) or degraded (T-score ≤ -2.5). TBS groups were stratified by BMD T-scores (normal, osteopenia, or osteoporosis) using minimum T-score of total hip, femoral neck, and spine to identify categories in which TBS may be of more clinical use. The main outcome measure was the proportion of change in clinician’s treatment threshold between BMD alone and BMD plus TBS. The difference was assessed for significance using Chi-square test. Additionally, the change in UK National Osteoporosis Guideline Group (NOGG) threshold was also assessed using TBS-adjusted FRAX scores. Correlations between BMD-TBS strata and the change in intervention threshold (yes/no) were carried out using Spearman test.

Results:

540 patients were analysed. The inclusion of TBS resulted in 8.2% change in clinician’s treatment threshold (p <0.001) shifting the outcome 6.5 % for and 1.7 % against treatment. More than half of the cases in which the clinical decision was changed were for patients with osteopenia and degraded TBS (significant correlation; P <0.001). NOGG intervention threshold was changed in 7.4% of the cases (P<0.001); 6.1% for and 1.3% against treatment. 37.5% of NOGG changed outcome was related to osteopenia with degraded TBS (p<0.001). Kappa agreement between the clinician and NOGG was fair at 0.42 (p<0.001).

Conclusion:

These results demonstrate that using TBS in routine clinical practice is most likely to impact treatment decision in patients with osteopenia who have compromised bone microarchitecture. Incorporating TBS in routine DXA scans may lead to a net increase in bone protective therapy of approximately 5%. It is unknown whether adopting such an approach universally can reduce future fracture risk, and prospective studies are needed to address this question.

References:

[1]Hans D et al. J Bone Miner Res. 2011;26(11):2762-9.

[2]McCloskey EV et al. Calcif Tissue Int. 2015;96(6):500-9.

Table 1.

Demographic and baseline characteristics (n = 540)

Female470 (87%)Age (years)68.1 ± 11.6Body mass index (BMI)26.2 ± 4.6Femoral neck T-score-1.80 ± 1.04Total hip T-score-1.32 ± 1.07Lumbar spine T-score-1.37 ± 1.42Lumbar spine TBS1.32 ± 0.13Major osteoporotic fractures238 (44%)Spinal fractures81 (15%)FRAX major osteoporotic fracture14.43 ± 9.03FRAX hip fracture4.60 ± 6.20TBS-adjusted FRAX major osteoporotic fracture13.82 ± 8.80TBS-adjusted FRAX hip fracture4.45 ± 5.73Figure 1.

Distribution of changed clinical treatment threshold in normal, moderate, and degraded TBS according to BMD T-score

Acknowledgments:

Bone density unit &Rheumatology team, Robert Jones and Agnes Hunt Orthopaedic Hospital

Disclosure of Interests:

None declared

Moving beyond the mousetrap: current and emerging humanized mouse and rat models for investigating prevention and cure strategies against HIV infection and associated pathologies

The development of safe and effective combination antiretroviral therapies for human immunodeficiency virus (HIV) infection over the past several decades has significantly reduced HIV-associated morbidity and mortality. Additionally, antiretroviral drugs have provided an effective means of protection against HIV transmission. Despite these advances, significant limitations exist; namely, the inability to eliminate HIV reservoirs, the inability to reverse lymphoid tissues damage, and the lack of an effective vaccine for preventing HIV transmission. Evaluation of the safety and efficacy of therapeutics and vaccines for eliminating HIV reservoirs and preventing HIV transmission requires robust in vivo models. Since HIV is a human-specific pathogen, that targets hematopoietic lineage cells and lymphoid tissues, in vivo animal models for HIV-host interactions require incorporation of human hematopoietic lineage cells and lymphoid tissues. In this review, we will discuss the construction of mouse models with human lymphoid tissues and/or hematopoietic lineage cells, termed, human immune system (HIS)-humanized mice. These HIS-humanized mouse models can support the development of functional human innate and adaptive immune cells, along with primary (thymus) and secondary (spleen) lymphoid tissues. We will discuss applications of HIS-humanized mouse models in evaluating the safety and efficacy of therapeutics against HIV reservoirs and associated immunopathology, and delineate the human immune response elicited by candidate HIV vaccines. In addition to focusing on how these HIS-humanized mouse models have already furthered our understanding of HIV and contributed to HIV therapeutics development, we discuss how emerging HIS-humanized rat models could address the limitations of HIS-mouse models.

Prevalence of Low Back Pain, Pelvic Girdle Pain, and Combination Pain in a Postpartum Ontario Population

OBJECTIVE

The purpose of this study was to determine the point prevalence of low back pain (LBP), pelvic girdle pain (PGP), and/or combination pain (COMBO pain) and period prevalence (presence or absence of any of those pains), as well as to identify risk factors at 1, 3, and 6 months postpartum in a Canadian population.

METHODS

Participants from a previous pregnancy study participated in a postpartum survey administered over the telephone at 1, 3, and 6 months following delivery. The survey included questions about LBP, PGP, or COMBO pain during the postpartum period, as well as questions related to risk factors (Canadian Task Force Classification II-3).

RESULTS

At 1, 3, and 6 months postpartum, responses from 46, 58, and 64 participants, respectively, demonstrated that 15%-21% of women experienced LBP and up to 4% of women experienced COMBO pain (point prevalence). At no time point was PGP reported to occur alone. Period prevalence of back pain for the participants returned to pre-pregnancy levels at each time point. Back pain during pregnancy was the only risk factor identified for back pain at 3 and 6 months postpartum.

CONCLUSION

This study demonstrated that 76% to 80% of respondents were pain free at 1, 3, and 6 months postpartum. Pregnancy-related back pain was the only risk factor associated with postpartum-related pain at the 1 to 3 and 3 to 6 month time interval. Identification of site-specific postpartum-related back pain may assist in determination of management and treatment plans for this population.

Abstract A007: A Rag2/Il2rg double-knockout rat supports engraftment of human immune system for immunotherapy-based cancer efficacy studies

Immune humanized mice have been valuable in the development of novel cancer immunotherapies and have demonstrated stronger efficacy when combined with standard of care chemotherapy. An immune humanized rat could provide several advantages over the currently available humanized mouse models, including supporting the growth of larger tumors for serial fine needle biopsies to assess immune infiltration and serial blood draws for assessing human immune development and tumor biomarkers in real-time throughout an efficacy study. We developed a novel autologous human skin and immune cells-humanized rat model by co-engrafting full-thickness human-fetal skin and autologous fetal lymphoid organoids under the kidney capsule along with intravenous injection of autologous fetal-liver derived hematopoietic stem cells, thus termed, human skin-immune system humanized rat model (hSIS-humanized rat). hSIS-humanized rat support development of adult-like, full-thickness human skin and human lymphoid organoids along with human immune cells. Methicillin-resistant Staphylococcus aureus inoculation in the human skin results in infection and skin pathology, thus recapitulating clinical outcomes. This model will enable in vivo mechanistic studies for development and evaluation of novel therapeutics for skin infectious disease and may also provide a model for establishing skin grafts of patient-derived melanoma tumors to investigate melanoma metastasis and response to therapies. In addition, engrafting the rat with human lymphoid organs and human immune cells may provide a similar platform to the BLT mouse for immunotherapy studies. Finally, we have demonstrated humanization of the rat immune system using human PBMCs. Human CD45+, CD3+, and CD20+ cells can be found in the peripheral blood, spleen, and bone marrow of engrafted rats. These immune humanized rat models may be beneficial for evaluating immunotherapies in human cancer models, including assessment of immune cell infiltration through fine needle biopsies.

Citation Format: Fallon K Noto, Bisoye Towobola Adedeji, Yash Agarwal, Cole Beatty, Sara Ho, Antu Das, Rajeev Salunke, Moses Bility, Tseten Yeshi Jamling. A Rag2/Il2rg double-knockout rat supports engraftment of human immune system for immunotherapy-based cancer efficacy studies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A007. doi:10.1158/1535-7163.TARG-19-A007

Abstract P1-12-07: Prospective 36-month follow-up to determine changes in body mass index and weight among Chinese breast cancer survivors

Background:Anticancer treatment for breast cancer has been associated with weight gain but such observation has mainly been reported in western patients. More recent data in Asian patients have inconsistent findings. Factors including socio-demographic, clinical and lifestyle may be associated with post-diagnosis weight gain. In this prospective cohort study of women with breast cancer, the objectives were to determine the body mass index (BMI) and weight changes over 36 months after initial diagnosis and the factors associated with such changes.

Methods: Chinese women with newly diagnosed early-stage breast cancer were recruited. Individual woman had her weight measured at breast cancer diagnosis (W0), at study entry (W1) and at 36-month follow-up (W2). Body height was measured at W0. We evaluated change in weight and body mass index (BMI) before and after breast cancer diagnosis.Socio-demographic, clinical and lifestyle factors were assessed to identify potential associated factors with weight changes.

Results: A total of 1133 women with breast cancer had detailed weight measurements at the 3 time-points of assessment. The mean age at diagnosis was 52 years. Fifty-four percent were premenopausal at W1. The proportion of patients with stage 0-I, II and III diseases were 35%, 46% and 19%, respectively.

The proportions of patients who were overweight and obese at the three assessment time-points were 21.2% and 28.5% at W0, 19.7% and 26.6% at W1, and 21.7% and 30.9% at W2 assessment, respectively. When compared to W0, the proportions of women who gained weight within 2-5kg at W1 and W2 were 2.4% and 20.6% respectively, that with weight gain of &gt;5kg at W1 and W2 were 0.5% and 10.0% respectively; 6.1% and 19.6% of women had weight loss &gt;2kg at W1 and W2 respectively.

Compared to W0, the median value of weight change was -0.5 kg (range: -11.4, 18.3) at W1 and 0.6 kg (range: -19.6, 20.5) at W2. On multivariate analysis, only BMI at diagnosis were significantly associated with weight change betweenassessments at diagnosis and W2; the median (range) for weight changes for women who were underweight, normal, overweight and obese were respectively 0.9 (-4.8, 7.6), 0.6 (-13.2, 20.5), 0.5 (-11.5, 13.0) and 0.5 (-19.6, 12.6) kg, p &lt;0.001.

Conclusions: In this prospective study of Chinese women with a history of breast cancer who were followed-up over a 36-months' period, the proportions of women with overweight and obese statuses were relatively stable; weight gain was uncommon among Hong Kong women with breast cancer during the same period. These findings are in contrast with studies conducted in the West, where weight gains were more commonly reported.

Funding: World Cancer Research Fund International (Grant Number WCRF 2010/249 and WCRF 2014/1197)

Citation Format: Yeo W, Lei YY, Cheng AC, Kwok CC, Cheung KL, Lee R, Lee IC, He YQ, Ho S. Prospective 36-month follow-up to determine changes in body mass index and weight among Chinese breast cancer survivors [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-07.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Critical Role of Central Facilitation in the Glottic Closure Reflex

The sphincteric function of the larynx, essential to lower airway protection, is most efficiently achieved through strong reflex adduction by both vocal cords. We hypothesize that central facilitation is an essential component of a bilateral adductor reflex and that its disturbance could result in weakened sphincteric closure. Six adult 50-kg pigs underwent evoked response laryngeal electromyography under 0.5 to 1.0 minimal alveolar concentration (MAC) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. Consistent threshold responses were obtained ipsilaterally from 0.5 to 1.0 MAC anesthesia. However, the contralateral reflex responses approached 0% in successive trials as anesthetic levels approached 1.0 MAC. Alteration of central facilitation by deepening anesthesia abolishes the crossed adductor reflex, predisposing to a weakened glottic closure response. A precise understanding of this effect may improve the prevention of aspiration in patients emerging from prolonged sedation or under heavy psychotropic control.

Bioengineering bacteriophages to enhance the sensitivity of phage amplification-based paper fluidic detection of bacteria

Bacteriophage (phage) amplification is an attractive method for the detection of bacteria due to a narrow phage-host specificity, short amplification times, and the phages' ability to differentiate between viable and non-viable bacterial cells. The next step in phage-based bacteria detection is leveraging bioengineered phages to create low-cost, rapid, and easy-to-use detection platforms such as lateral flow assays. Our work establishes the proof-of-concept for the use of bioengineered T7 phage strains to increase the sensitivity of phage amplification-based lateral flow assays. We have demonstrated a greater than 10-fold increase in sensitivity using a phage-based protein reporter, maltose-binding protein, over the detection of replicated T7 phage viron itself, and a greater then 100-fold increase in sensitivity using a phage-based enzymatic reporter, alkaline phosphatase. This increase in sensitivity enabled us to detect 10(3)CFU/mL of Escherichia coli in broth after 7h, and by adding a filter concentration step, the ability to detect a regulatory relevant E. coli concentration of 100CFU/100mL in inoculated river water after 9h, where the current standard requires days for results. The combination of the paper fluidic format with phage-based detection provides a platform for the development of novel diagnostics that are sensitive, rapid, and easy to use.

Language and understanding of cardiopulmonary resuscitation amongst an aged inpatient population

Greater patient involvement in health decision-making requires exchange of information between the patient and the healthcare professionals. Decisions regarding healthcare at the end of life include consideration of cardiopulmonary resuscitation (CPR). The stated objectives of this study were to determine how often language around concepts of resuscitation is used in the community by examination of the English language corpora (ELC); to explore the understanding of the same language by a group of older hospital patients; and to determine the patients' knowledge of the process and success of CPR, as well as the sources of their information. Medical inpatients aged 75 years and older were surveyed to this end in the setting of a tertiary university teaching hospital. Interrogation of the Australian, British and American English Corpora was accomplished by a linguist, and a questionnaire and semi-structured interview were administered to ascertain patient knowledge. We demonstrated that although medical inpatients have some familiarity with terms relating to resuscitation, there is a lack of understanding of the context, process and outcomes of CPR. The predominant sources of information were television and print media. Examination of the ELC revealed a paucity of the use of terms related to resuscitation. This finding indicates that physicians have a duty of care to determine patients' understanding around resuscitation language, and terms used, in discussions of their preferences before assuming their engagement in shared decision-making. More open public discussion around death and resuscitation would increase the general knowledge of the population and would provide a better foundation for the discussions in times of need.

Effect of whole soy and purified daidzein on ambulatory blood pressure and endothelial function--a 6-month double-blind, randomized controlled trial among Chinese postmenopausal women with prehypertension

BACKGROUND/OBJECTIVES

Although observational studies suggest that soy foods or isoflavones are cardio-protective, clinical trials on whole soy or isoflavone daidzein (one major isoflavone and the precursor of equol) on blood pressure (BP) and endothelial function (EF) are few and have not been specifically conducted among equol producers, a population most likely to benefit from soy treatment.

SUBJECTS/METHODS

We performed a 6-month double-blind, randomized, placebo-controlled trial to examine the effect of whole soy (soy flour) or purified daidzein on BP and EF in prehypertensive or untreated hypertensive postmenopausal women verified to be equol producers. A total of 270 eligible women were recruited and randomized to either one of the three treatment groups, 40 g soy flour (whole soy group), 40 g low-fat milk powder+63 mg daidzein (daidzein group) or 40 g low-fat milk powder (active control group) daily, each given as a solid beverage powder for 6 months. The primary outcome measures were 24 h ambulatory BP (ABP) and EF assessed by flow-mediated dilation using brachial artery ultrasound.

RESULTS

A total of 253 subjects completed the study according to protocol. Urinary isoflavones indicated good compliance with the interventions. Intention to treat and per-protocol analysis indicated that there was no significant difference in the 6-month changes or % changes in parameters of ABP and brachial flow-mediated dilation among the three treatment groups. A further subgroup analysis among hypertensive women (n=138) did not alter the conclusions.

CONCLUSIONS

Whole soy and purified daidzein had no significant effect on BP and vascular function among equol-producing postmenopausal women with prehypertension or untreated hypertension.