Development and validation of 10-year risk prediction models of cardiovascular disease in Chinese type 2 diabetes mellitus patients in primary care using interpretable machine learning-based methods.

AIM: To develop 10-year cardiovascular disease (CVD) risk prediction models in Chinese patients with type 2 diabetes mellitus (T2DM) managed in primary care using machine learning (ML) methods. METHODS: In this 10-year population-based retrospective cohort study, 141 516 Chinese T2DM patients aged 18 years or above, without history of CVD or end-stage renal disease and managed in public primary care clinics in 2008, were included and followed up until December 2017. Two-thirds of the patients were randomly selected to develop sex-specific CVD risk prediction models. The remaining one-third of patients were used as the validation sample to evaluate the discrimination and calibration of the models. ML-based methods were applied to missing data imputation, predictor selection, risk prediction modelling, model interpretation, and model evaluation. Cox regression was used to develop the statistical models in parallel for comparison. RESULTS: During a median follow-up of 9.75 years, 32 445 patients (22.9%) developed CVD. Age, T2DM duration, urine albumin-to-creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), systolic blood pressure variability and glycated haemoglobin (HbA1c) variability were the most important predictors. ML models also identified nonlinear effects of several predictors, particularly the U-shaped effects of eGFR and body mass index. The ML models showed a Harrell's C statistic of >0.80 and good calibration. The ML models performed significantly better than the Cox regression models in CVD risk prediction and achieved better risk stratification for individual patients. CONCLUSION: Using routinely available predictors and ML-based algorithms, this study established 10-year CVD risk prediction models for Chinese T2DM patients in primary care. The findings highlight the importance of renal function indicators, and variability in both blood pressure and HbA1c as CVD predictors, which deserve more clinical attention. The derived risk prediction tools have the potential to support clinical decision making and encourage patients towards self-care, subject to further research confirming the models' feasibility, acceptability and applicability at the point of care.

Age-specific associations between the number of co-morbidities, all-cause mortality and public direct medical costs in patients with type 2 diabetes: A retrospective cohort study.

AIM: To evaluate the association between the number of co-morbidities, all-cause mortality and public health system expenditure in patients with type 2 diabetes (T2D) across different age groups. MATERIALS AND METHODS: A retrospective observational study of T2D patients using electronic health records in Hong Kong was conducted. Patients were stratified by age (< 50, 50-64, 65-79, ≥ 80 years) and the number of co-morbidities (0, 1, 2, 3, ≥ 4), defined using the Charlson Comorbidity Index and prevalent chronic diseases identified in local surveys. The association between the number of co-morbidities, all-cause mortality and direct medical costs was examined using Cox proportional hazard regression and the gamma generalized linear model with log link function. RESULTS: A total of 262 212 T2D patients with a median follow-up of 10 years were included. Hypertension and dyslipidaemia were the most common co-morbidities in all age groups. After age stratification, cardiovascular diseases dominated the top pair of co-morbidities in the older age groups (65-79 and ≥ 80 years), while inflammatory and liver disease were predominant among younger individuals. Compared with co-morbidity-free T2D patients, the hazard ratios (95% CI) of death for patients aged younger than 50 and 80 years or older with two co-morbidities were 1.31 (1.08-1.59) and 1.25 (1.15-1.36), respectively, and increased to 3.08 (2.25-4.21) and 1.98 (1.82-2.16), respectively, as the number of co-morbidities increased to four or more. Similar trends were observed for medical costs. CONCLUSIONS: Age-specific co-morbidity patterns were observed for patients with T2D. A greater number of co-morbidities was associated with increased mortality and healthcare costs, with stronger relationships observed among younger patients.

Prediction models and nomograms for 10-year risk of end-stage renal disease in Chinese type 2 diabetes mellitus patients in primary care.

AIMS: To develop and validate 10-year risk prediction models, nomograms and charts for end-stage renal disease (ESRD) in Chinese patients with type 2 diabetes mellitus (T2DM) in primary care, in order to guide individualized treatment. MATERIALS AND METHODS: This was a 10-year population-based observational cohort study. A total of 141 516 Chinese T2DM patients without history of cardiovascular disease or ESRD who were managed in public primary care clinics in 2008 were included and followed up until December 2017. Two-thirds of these patients were randomly selected to develop sex-specific ESRD risk prediction models using Cox regressions. The validity and accuracy of the models were tested on the remaining third of patients using Harrell's C-index. We selected variables based on their clinical and statistical importance to construct the nomograms and charts. RESULTS: The median follow-up period was 9.75 years. The cumulative incidence of ESRD was 6.0% (men: 6.1%, women: 5.9%). Age, diabetes duration, systolic blood pressure (SBP), SBP variability, diastolic blood pressure, triglycerides, glycated haemoglobin (HbA1c), HbA1c variability, urine albumin to creatinine ratio (UACR), and estimated glomerular filtration rate (eGFR) were significant predictors for both sexes. Smoking and total cholesterol to HDL cholesterol ratio were additional significant predictors for men and women, respectively. The models showed Harrell's C-statistics of 0.889/0.889 (women/men). Age, eGFR, UACR, SBP and HbA1c were selected for both sexes to develop nomograms and charts. CONCLUSIONS: Using routinely available variables, the 10-year ESRD risk of Chinese T2DM patients in primary care can be predicted with approximately 90% accuracy. We have developed different tools to facilitate routine ESRD risk prediction in primary care, so that individualized care can be provided to prevent or delay ESRD in T2DM patients.

Immune Responses to Twice-Annual Influenza Vaccination in Older Adults in Hong Kong.

Background: Many health authorities recommend influenza vaccination of older adults to reduce disease burden. We hypothesized that in tropical and subtropical areas with more prolonged influenza seasons, twice-annual influenza vaccination might provide older adults with improved immunity against influenza. Methods: In 2014-2015, Hong Kong experienced a substantial A(H3N2) winter epidemic with a mismatched vaccine. Local authorities procured and administered to older adults the 2015 southern hemisphere influenza vaccine, which included an updated and matching A/Switzerland/9715293/2013(H3N2) strain. We compared immune parameters in pre- and postvaccination sera from older adults ≥75 years of age who received 1 vs 2 influenza vaccines per year. Results: We enrolled 978 older adults with 470 vaccinations for summer 2015 and 827 vaccinations for winter 2015-2016. Recipients of southern hemisphere vaccination had higher geometric mean titers (GMTs) by the hemagglutination inhibition assay against all 3 vaccine strains. When receiving influenza vaccination for the subsequent winter, the southern hemisphere vaccine recipients had higher prevaccination GMTs but lower postvaccination GMTs, compared to those who had not received the southern hemisphere vaccine. Furthermore, cellular immunity was impacted by biannual vaccination, with reduced influenza-specific CD4 T-cell responses in the second season of vaccination. Conclusions: We observed some reductions in immune responses in the twice-annual vaccination group compared with the once-annual vaccination group, in the context of unchanging vaccine strains, while protection was likely to have been improved during the summer and autumn for the twice-annual vaccination group due to the continued circulation of the A/Switzerland/9715293/2013(H3N2) virus.

Knowledge, practices and expectations of preventive care: a qualitative study of patients attending government general outpatient clinics in Hong Kong.

BACKGROUND: Evidence-based preventive care recommendations have been well established, but studies have persistently reported gaps between these recommendations and general practitioners' practices in providing preventive care. Many studies have explored factors that affect the delivery of preventive care from the perspectives of the practitioners, but relatively few have evaluated the patients' point of view. The purpose of this study was to explore patients' understanding of preventive care, the actions they were taking in terms of preventive health and their expectations from family doctors in providing preventive care. METHODS: A qualitative study was conducted based on one-on-one in-depth interviews. Twenty-eight patients without chronic illnesses were purposively recruited from government general outpatient clinics in Hong Kong. The interviews took place between November 2013 and February 2014. RESULTS: The participants' knowledge of preventive care was limited, and their preventive practices were mostly restricted to healthy lifestyle practices. They rarely obtained individualised preventive care advice from doctors. Screening investigations were initiated after symptoms had already occurred, and the decision of what to check was arbitrary. Few of the participants knew what they wanted from their doctors in terms of preventive care. CONCLUSIONS: These findings show significant gaps between evidence-based preventive recommendations and patients' current knowledge and practice, and show the need for a wider spectrum of preventive care education and reliable sources to provide individualised and affordable preventive assessment and screening services. Most importantly, primary care providers must take a more proactive role to provide preventive services.

Altered regulation of DNA ligase IV activity by aberrant promoter DNA methylation and gene amplification in colorectal cancer.

Colorectal cancer (CRC) presents as a very heterogeneous disease which cannot sufficiently be characterized with the currently known genetic and epigenetic markers. To identify new markers for CRC we scrutinized the methylation status of 231 DNA repair-related genes by methyl-CpG immunoprecipitation followed by global methylation profiling on a CpG island microarray, as altered expression of these genes could drive genomic and chromosomal instability observed in these tumors. We show for the first time hypermethylation of MMP9, DNMT3A and LIG4 in CRC which was confirmed in two CRC patient groups with different ethnicity. DNA ligase IV (LIG4) showed strong differential promoter methylation (up to 60%) which coincided with downregulation of mRNA in 51% of cases. This functional association of LIG4 methylation and gene expression was supported by LIG4 re-expression in 5-aza-2'-deoxycytidine-treated colon cancer cell lines, and reduced ligase IV amounts and end-joining activity in extracts of tumors with hypermethylation. Methylation of LIG4 was not associated with other genetic and epigenetic markers of CRC in our study. As LIG4 is located on chromosome 13 which is frequently amplified in CRC, two loci were tested for gene amplification in a subset of 47 cases. Comparison of amplification, methylation and expression data revealed that, in 30% of samples, the LIG4 gene was amplified and methylated, but expression was not changed. In conclusion, hypermethylation of the LIG4 promoter is a new mechanism to control ligase IV expression. It may represent a new epigenetic marker for CRC independent of known markers.

Prevention in primary care is better than cure: The Hong Kong Reference Framework for Preventive Care for Older Adults--translating evidence into practice.

An ageing population is posing a great challenge to Hong Kong. Maintaining health and functional independence among older adults is of utmost importance, and requires the collaborative efforts of multiple health care disciplines from both the private and public sectors. The Reference Framework for Preventive Care for Older Adults, developed by the Task Force on Conceptual Model and Preventive Protocols under the auspices of the Working Group on Primary Care, aims to enhance primary care for this population group. The reference framework emphasises a comprehensive, integrated, and collaborative approach that involves providers of primary care from multiple disciplines. In addition to internet-based information, helpful tools in the form of summary charts and Cue Cards are also produced to facilitate incorporation of recommendations by primary care providers into their daily practice. It is anticipated that wide adoption of the reference framework will contribute to improving older adults' health in our community.

Comparative epidemiology of pandemic and seasonal influenza A in households.

BACKGROUND: There are few data on the comparative epidemiology and virology of the pandemic 2009 influenza A (H1N1) virus and cocirculating seasonal influenza A viruses in community settings. METHODS: We recruited 348 index patients with acute respiratory illness from 14 outpatient clinics in Hong Kong in July and August 2009. We then prospectively followed household members of 99 patients who tested positive for influenza A virus on rapid diagnostic testing. We collected nasal and throat swabs from all household members at three home visits within 7 days for testing by means of quantitative reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay and viral culture. Using hemagglutination-inhibition and viral-neutralization assays, we tested baseline and convalescent serum samples from a subgroup of patients for antibody responses to the pandemic and seasonal influenza A viruses. RESULTS: Secondary attack rates (as confirmed on RT-PCR assay) among household contacts of index patients were similar for the pandemic influenza virus (8%; 95% confidence interval [CI], 3 to 14) and seasonal influenza viruses (9%; 95% CI, 5 to 15). The patterns of viral shedding and the course of illness among index patients were also similar for the pandemic and seasonal influenza viruses. In a subgroup of patients for whom baseline and convalescent serum samples were available, 36% of household contacts who had serologic evidence of pandemic influenza virus infection did not shed detectable virus or report illness. CONCLUSIONS: Pandemic 2009 H1N1 virus has characteristics that are broadly similar to those of seasonal influenza A viruses in terms of rates of viral shedding, clinical illness, and transmissibility in the household setting.

Erectile dysfunction and lower urinary tract symptoms: prevalence and risk factors in a Hong Kong primary care setting.

OBJECTIVES: To study the prevalence and associated risk factors of erectile dysfunction and lower urinary tract symptoms in a primary care population in Hong Kong. DESIGN: Questionnaire study. SETTING: Sai Ying Pun Jockey Club General Outpatient Clinic, Hong Kong. PARTICIPANTS: Male patients (n=950) seen between November 2010 and February 2011. MAIN OUTCOME MEASURES: International Prostate Symptom Score, and the five-item version of the International Index of Erectile Function. RESULTS: The point prevalence of any degree of erectile dysfunction in our sample was 68% (mild 13%, mild-to-moderate 14%, moderate 16%, and severe 24%). Univariate analysis showed that age, education, working status, marital status, and smoking were associated factors. Further multiple logistic regression analysis identified age and smoking as significantly associated. The point prevalence of moderate and severe lower urinary tract symptoms was 36% and 32%, respectively. For the predictors of such symptoms, univariate analysis identified five factors (age, education, working status, marital status, and smoking) and only working status was not significantly associated with these symptoms in the multiple logistic regression analysis. The Pearson coefficient test showed a significant negative relation (r= -0.525; P<0.0001) between the two outcome measures (International Prostate Symptom Score and the five-item version of the International Index of Erectile Function). CONCLUSIONS: We showed that erectile dysfunction and lower urinary tract symptoms are common health problems in Chinese males seen in primary care. The correlation between the two outcome measures was statistically significant. Primary care physicians should increase awareness on erectile dysfunction and lower urinary tract symptoms so as to provide early screening and detection, as well as comprehensive treatment.

Ten-Year Effectiveness of the Multidisciplinary Risk Assessment and Management Programme-Diabetes Mellitus (RAMP-DM) on Macrovascular and Microvascular Complications and All-Cause Mortality: A Population-Based Cohort Study.

OBJECTIVE: The Risk Assessment and Management Programme-Diabetes Mellitus (RAMP-DM) is a protocol-driven, risk-stratified, and individualized management program offered by a multidisciplinary team in addition to usual care for primary care patients with diabetes. This study aimed to evaluate the effectiveness of RAMP-DM for preventing complications and mortality over 10 years. RESEARCH DESIGN AND METHODS: A population-based, prospective cohort study of adult patients with type 2 diabetes managed in the Hong Kong public primary health care system between 2009 and 2010 was conducted. RAMP-DM participants and usual care patients were matched using one-to-one propensity score matching and followed for 10 years. Risks of macrovascular and microvascular complications and all-cause mortality were estimated by Cox proportional hazards regression. RESULTS: A total of 36,746 patients (18,373 in each group) were included after propensity score matching, with a median follow-up of 9.5 years and 306,802 person-years. RAMP-DM participants had significantly lower risks of macrovascular (hazard ratio [HR] 0.52, 95% CI 0.50-0.54) and microvascular (HR 0.68, 95% CI 0.64-0.72) complications and all-cause mortality (HR 0.45, 95% CI 0.43-0.47) than patients who received usual care only. However, the effect of RAMP-DM on macrovascular and microvascular complications attenuated after the 9th and 8th year of follow-up, respectively. RAMP-DM participants also showed better control of hemoglobin A1c, blood pressure, triglycerides, and BMI and a slower decline in renal function. CONCLUSIONS: Significant reductions in diabetes-related complications and all-cause mortality were observed among RAMP-DM participants over a 10-year follow-up, yet the effect of preventing complications attenuated after 8 years.

Pulmonary emboli imaging with (99m)Tc-labelled anti-D-dimer (DI-80B3) Fab' followed by SPECT.

OBJECTIVES: Pre-clinical experiments demonstrated that intravenous (99m)Tc labelled DI-DD-3B6/22-80B3 humanised anti-fibrin-D-dimer Fab' fragments ((99m)Tc-DI-80B3) allowed scintigraphic imaging of acute pulmonary emboli (PE). The aims of this clinical study were to determine the safety of (99m)Tc-DI-80B3 in patients with PE and evaluate the resulting scintigraphic images for the localisation of acute PE. MATERIALS/PATIENTS AND METHODS: (99m)Tc-DI-80B3 (0.5mg, 710-850MBq) was administered intravenously to subjects (n=14) with segmental or larger PE on recent contrast-enhanced helical CT scans. Thoracic SPECT scans were acquired 15 minutes, 2 hours and 4 hours afterwards. Subjects were followed for 90 days subsequently. RESULTS: There were no serious adverse events or antibody responses associated with (99m)Tc-DI-80B3 administration. Focal accumulations of (99m)Tc-DI-80B3 on the SPECT images of the thorax acquired at four hours corresponded to pulmonary emboli detected by CT. Two independent "blinded" SPECT readers identified 79% and 71% (respectively) of the right lung and 79% and 64% (respectively) of the left lung in which CT scans disclosed PE. CONCLUSIONS: (99m)Tc-DI-80B3 is well-tolerated in patients with acute PE and does not induce an immune response. (99m)Tc-DI-80B3 may offer a novel approach to imaging PE in a clinically acceptable timeframe without exposure to potentially nephrotoxic radiographic contrast agents.

Screening for diabetic retinopathy with different levels of financial incentive in a randomized controlled trial.

AIMS/INTRODUCTION: To examine the impact of different levels of financial incentive in terms of fee subsidization on diabetic retinopathy screening in the private primary care setting in Hong Kong. MATERIALS AND METHODS: All general practitioners working in the private sector and registered in two electronic public databases were invited to participate. Consecutive patients with diabetes mellitus were then recruited by the participating practitioners. The recruited participants were randomly allocated to one of three screening groups with different fee levels (HK$0, HK$150 [US$19], HK$300 [US$39]) in a randomized controlled trial. Screening uptake and severity of diabetic retinopathy detected were compared. RESULTS: Out of 1,688 eligible practitioners, 105 participated and invited 402 patients, with 239 initially agreeing to participate (59.5%). After randomization, 78, 75 and 76 participants in the HK$0, HK$150 and HK$300 fee groups, respectively, reconfirmed their participation and were offered screening at the relevant fee. The uptake of screening was 79.5% (62/78), 81.3% (61/75) and 63.2% (48/76), in the HK$0, HK$150 and HK$300 groups, respectively (P < 0.018). Being in the HK$150 fee group was associated with higher uptake of screening than being in the HK$300 fee group (odds ratio 2.31, P = 0.039). No significant difference was found in the prevalence of any diabetic retinopathy (33.9%, 27.9% and 37.5%, P = 0.378) or sight-threatening diabetic retinopathy (4.8%, 8.2% and 16.7%; P = 0.092) among the groups. CONCLUSION: A screening fee of HK$150, representing approximately a half subsidy, appears to be as effective in maximizing uptake as a full subsidy (HK$0) and without deterring those at high risk of diabetic retinopathy from screening.

Retrospective cohort study to investigate the 10-year trajectories of disease patterns in patients with hypertension and/or diabetes mellitus on subsequent cardiovascular outcomes and health service utilisation: a study protocol.

INTRODUCTION: Hypertension (HT) and diabetes mellitus (DM) and are major disease burdens in all healthcare systems. Given their high impact on morbidity, premature death and direct medical costs, we need to optimise effectiveness and cost-effectiveness of primary care for patients with HT/DM. This study aims to find out the association of trajectories in disease patterns and treatment of patients with HT/DM including multimorbidity and continuity of care with disease outcomes and service utilisation over 10 years in order to identify better approaches to delivering primary care services. METHODS AND ANALYSIS: A 10-year retrospective cohort study on a population-based primary care cohort of Chinese patients with documented doctor-diagnosed HT and/or DM, managed in the Hong Kong Hospital Authority (HA) public primary care clinics from 1 January 2006 to 31 December 2019. Data will be extracted from the HA Clinical Management System to identify trajectory patterns of patients with HT/DM. Complications defined by ICPC-2/International Classification of Diseases-Ninth Revision, Clinical Modification diagnosis codes, all-cause mortality rates and public service utilisation rates are included as independent variables. Changes in clinical parameters will be investigated using a growth mixture modelling analysis with standard quadratic trajectories. Dependent variables including effects of multimorbidity, measured by (1) disease count and (2) Charlson's Comorbidity Index, and continuity of care, measured by the Usual Provide Continuity Index, on patient outcomes and health service utilisation will be investigated. Multivariable Cox proportional hazards regression will be conducted to estimate the effect of multimorbidity and continuity of care after stratification of patients into groups according to respective definitions. ETHICS AND DISSEMINATION: This study was approved by the institutional review board of the University of Hong Kong-the HA Hong Kong West Cluster, reference no: UW 19-329. The study findings will be disseminated through peer-reviewed publications and international conferences. TRIAL REGISTRATION NUMBER: NCT04302974.

Imaging of deep venous thrombosis in patients using a radiolabelled anti-D-dimer Fab' fragment (99mTc-DI-DD3B6/22-80B3): results of a phase I trial.

PURPOSE: (99m)Tc-DI-DD3B6/22-80B3 (ThromboView, hereafter abbreviated to (99m)Tc-DI-80B3 Fab') is a radiolabelled humanised monoclonal Fab' fragment with affinity and specificity for D-dimer domains of cross-linked fibrin. Detection of thromboembolic events has been demonstrated in canine models. The study objectives were evaluation of safety and characterisation of biodistribution, immunogenicity and pharmacokinetic profile of increasing doses of (99m)Tc-DI-80B3 Fab' in subjects with acute lower-limb DVT. METHODS: Twenty-six patients with acute lower limb DVT were enrolled. Of these, 21 received a single intravenous dose of 0.5 mg (n = 6), 1.0 mg (n = 9) or 2 mg (n = 6) (99m)Tc-DI-80B3 Fab'. Blood and urine samples and gamma camera images were collected to 24 h after administration for pharmacokinetic and dosimetry analysis. Vital signs, electrocardiography, hematological and biochemical data and human anti-human antibody (HAHA) levels were monitored for up to 30 days following administration. Patients were assigned to either planar or single photon emission computed tomographic (SPECT) imaging of the thorax at 4 h following injection. RESULTS: Thirty-five adverse events were reported in 15 of the 21 subjects. Those deemed possibly related to administration of (99m)Tc-DI-80B3 Fab' included mild hypertension, mild elevation of LD (lactate dehydrogenase) and moderate elevation of ALT (alanine transaminase). HAHA assays remained negative. Pharmacokinetics and organ dosimetry were comparable to prior normal volunteer data. Localisation of Thromboview to sites of known thrombus was evident as early as 30 min post-injection. CONCLUSIONS: In subjects with acute DVT, (99m)Tc-DI-80B3 Fab' was well tolerated with favourable characteristics for the detection of acute venous thrombosis.

Ten-year risk prediction models of complications and mortality of Chinese patients with diabetes mellitus in primary care in Hong Kong: a study protocol.

INTRODUCTION: Diabetes mellitus (DM) is a major disease burden worldwide because it is associated with disabling and lethal complications. DM complication risk assessment and stratification is key to cost-effective management and tertiary prevention for patients with diabetes in primary care. Existing risk prediction functions were found to be inaccurate in Chinese patients with diabetes in primary care. This study aims to develop 10-year risk prediction models for total cardiovascular diseases (CVD) and all-cause mortality among Chinese patients with DM in primary care. METHODS AND ANALYSIS: A 10-year cohort study on a population-based primary care cohort of Chinese patients with diabetes, who were receiving care in the Hospital Authority General Outpatient Clinic on or before 1 January 2008, were identified from the clinical management system database of the Hospital Authority. All patients with complete baseline risk factors will be included and followed from 1 January 2008 to 31 December 2017 for the development and validation of prediction models. The analyses will be carried out separately for men and women. Two-thirds of subjects will be randomly selected as the training sample for model development. Cox regressions will be used to develop 10-year risk prediction models of total CVD and all-cause mortality. The validity of models will be tested on the remaining one-third of subjects by Harrell's C-statistics and calibration plot. Risk prediction models for diabetic complications specific to Chinese patients in primary care will enable accurate risk stratification, prioritisation of resources and more cost-effective interventions for patients with DM in primary care. ETHICS AND DISSEMINATION: The study was approved by the Institutional Review Board of the University of Hong Kong-the Hospital Authority Hong Kong West Cluster (reference number: UW 15-258). TRIAL REGISTRATION NUMBER: NCT03299010; Pre-results.

Similarity of the phenotypic patterns associated with BRAF and KRAS mutations in colorectal neoplasia.

Activation of the RAS/RAF/extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase pathway by RAS mutations is commonly found in human cancers. Recently, we reported that mutation of BRAF provides an alternative route for activation of this signaling pathway and can be found in melanomas, colorectal cancers, and ovarian tumors. Here we perform an extensive characterization of BRAF mutations in a large series of colorectal tumors in various stages of neoplastic transformation. BRAF mutations were found in 11 of 215 (5.1%) colorectal adenocarcinomas, 3 of 108 (2.8%) sporadic adenomas, 1 of 63 (1.6%) adenomas from familial adenomatous polyposis (FAP) patients, and 1 of 3 (33%) hyperplastic polyps. KRAS mutations were detected in 34% of carcinomas, 31% of sporadic adenomas, 9% of FAP adenomas, and no hyperplastic polyps. Eight of 16 BRAF mutations were V599E, the previously described hotspot, and none of these was associated with a KRAS mutation in the same lesion. The remaining eight mutations involve other conserved amino acids in the kinase domain, and 62.5% have a KRAS mutation in the same tumor. Our data suggest that BRAF mutations are, to some extent, biologically similar to RAS mutations in colorectal cancer because both occur at approximately the same stage of the adenoma-carcinoma sequence, both are associated with villous morphology, and both are less common in adenomas from FAP cases. By contrast, colorectal adenocarcinomas with BRAF mutations are associated with early Dukes' tumor stages (P = 0.006) and no such relationship was observed for KRAS mutations. The presence in some colorectal neoplasms of mutations in both BRAF and KRAS suggests that modulation of the RAS-RAF-extracellular signal-regulated kinase-mitogen-activated protein kinase/extracellular signal-regulated kinase/mitogen-activated protein kinase signaling pathway may occur by mutation of multiple components.

Intralesional targeted alpha therapy for metastatic melanoma.

UNLABELLED: This paper reports the development and application of intralesional targeted alpha therapy (TAT) for melanoma, being the first part of a program to establish a new systemic therapy. RATIONALE: Labelling the benign targeting vector 9.2.27 with 213Bi forms the alpha-immunoconjugate (AIC), which is highly cytotoxic to targeted melanoma cells. OBJECTIVE: To investigate the safety and efficacy of intralesional AIC in patients with metastatic skin melanoma. FINDINGS: 16 melanoma patients were recruited. All the patients were positive to the monoclonal antibody 9.2.27. AIC doses from 50 to 450 mCi injected into lesions of different sizes resulted in massive cell death, as observed by the presence of tumour debris. The AIC was very effective in delivering a high dose to the tumour while sparing other tissues. There were no significant changes in blood proteins and electrolytes. There was no evidence of a human-antimouse-antibody reaction. Evidence of significant decline in serum marker melanoma-inhibitory-activity protein (MIA) at 2 weeks post-TAT was observed. CONCLUSIONS: Intralesional TAT for melanoma was found to be quite safe up to 450 mCi, and efficacious at a dose of 200 mCi. MIA, apoptosis and ki67 proliferation marker tests all indicated that TAT is a promising therapy for the control of inoperable secondary melanoma or primary ocular melanoma.

The Correlation of Retinal Nerve Fiber Layer Thickness With Blood Pressure in a Chinese Hypertensive Population.

To investigate the association between retinal nerve fiber layer (RNFL) thickness and blood pressure (BP) in subjects with systemic hypertension. Subjects with systemic hypertension on anti-hypertensive medications were screened by fundus photography and referred for glaucoma work-up if there was enlarged vertical cup-to-disc (VCDR) ratio ≥0.6, VCDR asymmetry ≥0.2, or optic disc hemorrhage. Workup included a complete ophthalmological examination, Humphrey visual field test, and RNFL thickness measurement by optical coherence tomography. The intraocular pressure (IOP) and RNFL thicknesses (global and quadrant) were averaged from both eyes and the means were correlated with: the systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) using Pearson correlation. Among 4000 screened hypertensive subjects, 133 were referred for glaucoma workup and 110 completed the workup. Of the 4000 screened subjects, 1.3% had glaucoma (0.9% had normal tension glaucoma [NTG], 0.2% had primary open angle glaucoma, and 0.2% had primary angle closure glaucoma), whereas 0.3% were NTG suspects. The SBP was negatively correlated with the mean superior RNFL thickness (P = 0.01). The DBP was negatively correlated with the mean global (P = 0.03), superior (P = 0.02), and nasal (P = 0.003) RNFL thickness. The MAP was negatively correlated with the mean global (P = 0.01), superior (P = 0.002), and nasal (P = 0.004) RNFL thickness while positively correlated with the mean IOP (P = 0.02). In medically treated hypertensive subjects, glaucoma was present in 1.3%, with NTG being most prevalent. MAP control may help with IOP lowering and RNFL preservation, although future prospective studies will be needed.

Targeted alpha therapy for cancer.

Targeted alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The practicality and efficacy of TAT is tested by in vitro and in vivo studies in melanoma, leukaemia, colorectal, breast and prostate cancers, and by a phase 1 trial of intralesional TAT for melanoma. The alpha-emitting radioisotope used is Bi-213, which is eluted from the Ac-225 generator and chelated to a cancer specific monoclonal antibody (mab) or protein (e.g. plasminogen activator inhibitor-2 PAI2) to form the alpha-conjugate (AC). Stable alpha-ACs have been produced which have been tested for specificity and cytotoxicity in vitro against melanoma (9.2.27 mab), leukaemia (WM60), colorectal (C30.6), breast (PAI2, herceptin), ovarian (PAI2, herceptin, C595), prostate (PAI2, J591) and pancreatic (PAI2, C595) cancers. Subcutaneous inoculation of 1-1.5 million human cancer cells into the flanks of nude mice causes tumours to grow in all mice. Tumour growth is compared for untreated controls, nonspecific AC and specific AC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. The 213Bi-9.2.27 AC is injected into secondary skin melanomas in stage 4 patients in a dose escalation study to determine the effective tolerance dose, and to measure kinematics to obtain the equivalent dose to organs. In vitro studies show that TAT is one to two orders of magnitude more cytotoxic to targeted cells than non-specific ACs, specific beta emitting conjugates or free isotopes. In vivo local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Intra-lesional TAT can completely regress advanced sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts and gives almost complete control of breast and prostate cancer tumour growth. Intralesional doses up to 450 microCi in human patients are effective in regressing melanomas, with no concomitant complications. These results point to the application of local and systemic TAT in the management of secondary cancer. Results of the phase 1 clinical trial of TAT of subcutaneous, secondary melanoma indicate proof of the principle that TAT can make tumours in patients regress.

Absence of detectable influenza RNA transmitted via aerosol during various human respiratory activities--experiments from Singapore and Hong Kong.

Two independent studies by two separate research teams (from Hong Kong and Singapore) failed to detect any influenza RNA landing on, or inhaled by, a life-like, human manikin target, after exposure to naturally influenza-infected volunteers. For the Hong Kong experiments, 9 influenza-infected volunteers were recruited to breathe, talk/count and cough, from 0.1 m and 0.5 m distance, onto a mouth-breathing manikin. Aerosolised droplets exhaled from the volunteers and entering the manikin's mouth were collected with PTFE filters and an aerosol sampler, in separate experiments. Virus detection was performed using an in-house influenza RNA reverse-transcription polymerase chain reaction (RT-PCR) assay. No influenza RNA was detected from any of the PTFE filters or air samples. For the Singapore experiments, 6 influenza-infected volunteers were asked to breathe (nasal/mouth breathing), talk (counting in English/second language), cough (from 1 m/0.1 m away) and laugh, onto a thermal, breathing manikin. The manikin's face was swabbed at specific points (around both eyes, the nostrils and the mouth) before and after exposure to each of these respiratory activities, and was cleaned between each activity with medical grade alcohol swabs. Shadowgraph imaging was used to record the generation of these respiratory aerosols from the infected volunteers and their impact onto the target manikin. No influenza RNA was detected from any of these swabs with either team's in-house diagnostic influenza assays. All the influenza-infected volunteers had diagnostic swabs taken at recruitment that confirmed influenza (A/H1, A/H3 or B) infection with high viral loads, ranging from 10(5)-10(8) copies/mL (Hong Kong volunteers/assay) and 10(4)-10(7) copies/mL influenza viral RNA (Singapore volunteers/assay). These findings suggest that influenza RNA may not be readily transmitted from naturally-infected human source to susceptible recipients via these natural respiratory activities, within these exposure time-frames. Various reasons are discussed in an attempt to explain these findings.