Myocardial Aging among a Population-Based Cohort Is Associated with Adverse Cardiovascular Outcomes and Sex-Specific Differences among Older Adults

INTRODUCTION

Despite growing calls to tackle aging-related cardiovascular disease (CVD), the role of detecting early diastolic dysfunction such as those observed in aging, prior to clinical disease, is of unclear clinical benefit.

METHODS

Myocardial function determined by echocardiography was examined in association with incident cardiovascular outcomes or all-cause death by Cox proportional hazards model. Sex-based differences in outcomes were included.

RESULTS

A total of 956 participants (mean age 63 ± 12.9 years, n = 424 males [44%]) were categorized based on mitral peak early-to-late diastolic filling velocity (E/A) ratios: E/A <0.8 (28%), E/A 0.8-1.2 (39%), E/A (29%), E/A >2.0 (4%). Incidence rate (IR) for non-fatal cardiovascular outcomes was 2.83 per 100 person-years (95% CI: 2.24-3.56) and 0.45 per 100 person-years (95% CI: 0.26-0.80) for all-cause death. Event-free survival from non-fatal cardiovascular outcomes was significantly different among E/A categories (log-rank p = 0.0269). E/A <0.8 (HR 1.80, 95% CI: 1.031, 3.14, p = 0.039) was associated with non-fatal cardiovascular outcomes. Among men, IR for cardiovascular outcomes was 3.56 per 100 person-years (95% CI: 2.62-4.84) and 0.75 per 100 person-years (95% CI: 0.39-1.44) for all-cause death. Among women, IR for cardiovascular outcomes was 2.22 per 100 person-years (95% CI: 1.56-3.16) and 0.21 per 100 person-years (95% CI: 0.067-0.64) for all-cause death. For E/A <0.8 category, women had significantly higher risks of non-fatal cardiovascular outcomes, compared to E/A 0.8-1.2 category (HR 2.49, 95% CI: 1.18, 5.23, p = 0.017).

CONCLUSION

Myocardial aging was an independent predictor of cardiovascular outcomes in community-dwelling older adults prior to clinical CVD. Impaired myocardial relaxation was prevalent in both sexes but associated with worse outcomes in women, suggestive of sex differences in age-related biology.

BNT162b2 vaccine protection against omicron and effect of previous infection variant and vaccination sequence among children and adolescents in Singapore: a population-based cohort study

BACKGROUND

Information on variant-specific vaccine protection and the effect of previous infection variant is scarce in children. We aimed to ascertain the level of protection conferred by BNT162b2 COVID-19 vaccination against omicron variant infection (BA.4 or BA.5, and XBB) in a previously infected national paediatric cohort. We also explored the association between sequence of previous infection (variant) and vaccination on protection.

METHODS

We did a retrospective, population-based cohort study using the national databases of all confirmed SARS-CoV-2 infections, vaccines administered, and demographic records maintained by the Ministry of Health, Singapore. The study cohort consisted of children aged 5-11 years and adolescents aged 12-17 years who had a previous SARS-CoV-2 infection from Jan 1, 2020, to Dec 15, 2022. People who were infected during the pre-delta period or were immunocompromised (received three vaccination doses [children 5-11 years old] and four vaccinations doses [adolescents 12-17 years old]) were excluded. Those who had multiple episodes of infection before the study start date, were not vaccinated before infection but completed three doses, received bivalent mRNA vaccine, or received non-mRNA vaccine doses were also excluded. All SARS-CoV-2 infections confirmed by reverse transcriptase polymerase chain reaction or rapid antigen testing were grouped into delta, BA.1, BA.2, BA.4 or BA.5, or XBB variants using a combination of whole-genome sequencing, S-gene target failure results, and imputation. For BA.4 or BA.5, the study outcome period was June 1-Sept 30, 2022, and for XBB variants the outcome period was Oct 18-Dec 15, 2022. Incidence rate ratios between vaccinated and unvaccinated were derived using adjusted Poisson regressions and vaccine effectiveness was estimated as (1-risk ratio) × 100%.

FINDINGS

135 197 people aged 5-17 years (79 332 children and 55 865 adolescents) were included in the cohort for the vaccine effectiveness analysis against omicron BA.4 or BA.5, and 164 704 people aged 5-17 years (97 235 children and 67 469 adolescents) were included for the analysis against omicron XBB. Approximately 47% of participants were female and 53% were male. Among those previously infected, vaccine effectiveness against BA.4 or BA.5 infection in fully vaccinated children (two doses) was 74·0% (95% CI 67·7-79·1) and in adolescents (three doses) was 85·7% (80·2-89·6). Against XBB, protection conferred with full vaccination was lower at 62·8% (95% CI 42·3-76·0) in children and 47·9% (20·2-66·1) in adolescents. In children, receipt of two-dose vaccination before first SARS-CoV-2 infection provided them with the highest protection against subsequent BA.4 or BA.5 infection at 85·3% (95% CI 80·2-89·1); however, this was not shown to be the case for adolescents. First infection variant had an effect on vaccine effectiveness against omicron BA.4 or BA.5 reinfection in the following descending order: BA.2 conferred the highest protection (92·3% [95% CI 88·9-94·7] in children and 96·4% [93·5-98·0] in adolescents) followed by BA.1 (81·9% [75·9-86·4] in children and 95·0% [91·6-97·0] in adolescents), and delta which conferred the lowest protection (51·9% [5·3-75·6] in children and 77·5% [63·9-86·0] in adolescents).

INTERPRETATION

In previously infected children and adolescents, BNT162b2 vaccination provided additional protection against omicron BA.4 or BA.5 and XBB variants compared with those who remained unvaccinated. Hybrid immunity against XBB was lower than against BA.4 or BA.5, especially in adolescents. Early vaccination of previously uninfected children before their first SARS-CoV-2 exposure could potentially strengthen population immunity resilience against future variants.

FUNDING

None.

Effectiveness of BNT162b2 Vaccine against Omicron in Children 5 to 11 Years of Age

BACKGROUND

Since it was first identified in early November 2021, the B.1.1.529 (omicron) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread quickly and replaced the B.1.617.2 (delta) variant as the dominant variant in many countries. Data on the real-world effectiveness of vaccines against the omicron variant in children are lacking.

METHODS

In a study conducted from January 21, 2022, through April 8, 2022, when the omicron variant was spreading rapidly, we analyzed data on children in Singapore who were 5 to 11 years of age. We assessed the incidences of all reported SARS-CoV-2 infections (confirmed on polymerase-chain-reaction [PCR] assay, rapid antigen testing, or both), SARS-CoV-2 infections confirmed on PCR assay, and coronavirus disease 2019 (Covid-19)-related hospitalizations among unvaccinated, partially vaccinated (≥1 day after the first dose of vaccine and up to 6 days after the second dose), and fully vaccinated children (≥7 days after the second dose). Poisson regression was used to estimate vaccine effectiveness from the incidence rate ratio of outcomes.

RESULTS

A total of 255,936 children were included in the analysis. Among unvaccinated children, the crude incidence rates of all reported SARS-CoV-2 infections, PCR-confirmed SARS-CoV-2 infections, and Covid-19-related hospitalizations were 3303.5, 473.8, and 30.0 per 1 million person-days, respectively. Among partially vaccinated children, vaccine effectiveness was 13.6% (95% confidence interval [CI], 11.7 to 15.5) against all SARS-CoV-2 infections, 24.3% (95% CI, 19.5 to 28.9) against PCR-confirmed SARS-CoV-2 infection, and 42.3% (95% CI, 24.9 to 55.7) against Covid-19-related hospitalization; in fully vaccinated children, vaccine effectiveness was 36.8% (95% CI, 35.3 to 38.2), 65.3% (95% CI, 62.0 to 68.3), and 82.7% (95% CI, 74.8 to 88.2), respectively.

CONCLUSIONS

During a period when the omicron variant was predominant, BNT162b2 vaccination reduced the risks of SARS-CoV-2 infection and Covid-19-related hospitalization among children 5 to 11 years of age.

Nationwide Alcohol-related visits In Singapore's Emergency departments (NAISE): A retrospective population-level study from 2007 to 2016

INTRODUCTION

Excessive alcohol consumption is associated with increased morbidity and mortality, and its societal impact is substantial. The Nationwide Alcohol-related visits In Singapore Emergency departments study aims to characterise trends in ED visits involving acute and chronic alcohol consumption between 2007 and 2016.

METHODS

Data from the Singapore Ministry of Health, comprising all ED visits in Singapore from 2007 to 2016, were used. The data were aggregated by year and analysed for changes in prevalence and rates of ED visits for acute and chronic alcohol consumption, broken down by age, gender and ethnicity.

RESULTS

Over the study period, the number of ED visits involving alcohol consumption increased 98.3%, from 2236 in 2007 to 4433 in 2016. During the same period, the rate per 100 000 population increased 62.4% from 48.7 to 79.1, and total ED-related costs rose by 140%, from 528 680 to 1 269 638 SGD. The increase in alcohol-related visits rates and costs was higher than non-alcohol-related visits rates and costs, which increased by 12.1% and 115% respectively. While trends in acute and chronic alcohol-related ED visits stayed stable amongst women, they rose substantially in men. Older men aged 50-69 show the highest rates and rate of increase for both acute and chronic alcohol-related ED visits.

DISCUSSION AND CONCLUSIONS

Alcohol-related visits contributed disproportionately to the increasing number of ED visits in Singapore between 2007 and 2016. Older men form the demographic with the highest rates and increase in rates of alcohol-related ED visits and form a potential group for targeted intervention.

National Rates of Lower Extremity Amputation in People With and Without Diabetes in a Multi-Ethnic Asian Population: a Ten Year Study in Singapore

OBJECTIVE

Population level data from Asia on amputation rates in people with and without diabetes are extremely limited. Hence it is unclear how the rising diabetes prevalence in Asia has affected the amputation burden. The present study examined national amputation rates in people with and without diabetes in Singapore from 2008 to 2017 in the context of increasing diabetes prevalence and health system changes.

METHODS

This was a retrospective observational study using national population data for ages 16 - 100 years obtained from the Ministry of Health Singapore administrative datasets. Age sex standardised major and toe/ray amputation rates per 100 000 people with diabetes and per 100 000 people without diabetes were calculated. Rates were calculated overall and in each ethnic group (Chinese, Malay, Indian, Others), with trends over time calculated using joinpoint trend analysis. In addition, age specific rates, relative risk (RR) of amputation in diabetics compared with non-diabetics and proportion of amputations in the population attributable to diabetes were also calculated.

RESULTS

Between 2008 and 2017, the database included 3.6 million unique individuals, of whom 75% were Chinese, 8.6% Malay, 7.9% Indian, and 8.4% Others. Of those, 413 486 (11%) had diabetes. Major amputation rates in people with diabetes remained stable (2008: 99.5/100 000; 2017: 95.0/100 000 people with diabetes, p = .91) as did toe/ray amputation rates. Rates in people without diabetes were substantially lower, with major amputation rates decreasing significantly (2008: 3.0/100 000; 2017: 2.1/100 000 people without diabetes, 3% annual reduction, p = .048). Diabetes related amputation rates were highest in Malays and lowest in Chinese. Diabetes related major amputation rates declined significantly among Chinese (3.1% annual reduction, p < .038). While the RR for amputations in diabetes remained stable, the proportion of major amputations attributable to diabetes increased from 63.6% in 2008 to 81.7% in 2017 (3% annual increase, p = .003).

CONCLUSION

Diabetes related major and toe/ray amputation rates have remained stable but relatively high in Singapore compared with other countries, and the proportion of amputations attributable to diabetes has increased over time. More research is needed to understand the aetiopathological, sociocultural, and health system factors that may underlie the continued high rates of diabetes related amputations in this population.

Excess mortality after hip fracture: fracture or pre-fall comorbidity?

Comorbidity and hip fracture independently increased mortality risk for 9 years in both sexes, with a significant additive interaction in the first year among women and through 6 years among men.

INTRODUCTION

Hip fracture is associated with a persistently elevated mortality risk, but it is unknown whether the elevated risk is due to the fracture or to pre-fracture comorbidity.

METHODS

In a population-based study in Singapore with 9 years of follow-up, patients age > 50 with first hip fracture from 2008 to 2017 were pair-matched to a cohort without hip fracture by age, sex, ethnicity, and pre-fracture Charlson Comorbidity Index (CCI). We investigated additive interaction using the relative excess risk due to interaction (RERI) and multiplicative interaction using the ratio of relative risks.

RESULTS

Twenty-two thousand five hundred ninety of 22,826 patients with a first hip fracture in 2008-2017 were successfully matched. Hip fracture and comorbidity independently increased mortality risk for 9 years in both sexes. After adjustment for comorbidity, excess mortality risk continued to persist for 9 years post-fracture in both men and women. Women with a hip fracture and pre-fracture CCI > 4 had a higher relative risk (RR) of mortality at 9 years of 3.29 [95% confidence interval (CI) 3.01, 3.59] than those without comorbidity (RR 1.51, 95%CI 1.36, 1.68) compared to the referent without hip fracture or comorbidity. An additive interaction between hip fracture and pre-fracture CCI > 4 was observed in the first post-fracture year` [relative excess risk due to interaction (RERI) 1.99, 95%CI 0.97, 3.01]. For men with CCI ≥ 4, the positive additive interaction was observed through 6 years.

CONCLUSIONS

Excess mortality risks post-fracture are attributable to both the fracture and pre-fracture comorbidity. Early interventions in hip fracture patients with high comorbidity could reduce their excess mortality.

Diabetes-related lower extremity complications in a multi-ethnic Asian population: a 10 year observational study in Singapore

AIMS/HYPOTHESIS

Diabetes progression and complication risk are different in Asian people compared with those of European ancestry. In this study, we sought to understand the epidemiology of diabetes-related lower extremity complications (DRLECs: symptomatic peripheral arterial disease, ulceration, infection, gangrene) and amputations in a multi-ethnic Asian population.

METHODS

This was a retrospective observational study using data obtained from one of three integrated public healthcare clusters in Singapore. The population consisted of individuals with incident type 2 diabetes who were of Chinese, Malay, Indian or Other ethnicity. We examined incidence, time to event and risk factors of DRLECs and amputation.

RESULTS

Between 2007 and 2017, of the 156,593 individuals with incident type 2 diabetes, 20,744 developed a DRLEC, of whom 1208 underwent amputation. Age- and sex-standardised incidence of first DRLEC and first amputation was 28.29/1000 person-years of diabetes and 8.18/1000 person-years of DRLEC, respectively. Incidence of both was highest in individuals of Malay ethnicity (DRLEC, 36.09/1000 person-years of diabetes; amputation, 12.96/1000 person-years of DRLEC). Median time from diabetes diagnosis in the public healthcare system to first DRLEC was 30.5 months for those without subsequent amputation and 10.9 months for those with subsequent amputation. Median time from DRLEC to first amputation was 2.3 months. Older age (p < 0.001), male sex (p < 0.001), Malay ethnicity (p < 0.001), Indian ethnicity (p = 0.014), chronic comorbidities (nephropathy [p < 0.001], heart disease [p < 0.001], stroke [p < 0.001], retinopathy [p < 0.001], neuropathy [p < 0.001]), poorer or missing HbA_1c (p < 0.001), lower (p < 0.001) or missing (p = 0.002) eGFR, greater or missing BMI (p < 0.001), missing LDL-cholesterol (p < 0.001) at diagnosis, and ever-smoking (p < 0.001) were associated with higher hazard of DRLEC. Retinopathy (p < 0.001), peripheral vascular disease (p < 0.001), poorer HbA_1c (p < 0.001), higher (p = 0.009) or missing (p < 0.001) LDL-cholesterol and missing BMI (p = 0.008) were associated with higher hazard of amputation in those with DRLEC. Indian ethnicity (p = 0.007) was associated with significantly lower hazard of amputation.

CONCLUSIONS/INTERPRETATION

This study has revealed important ethnic differences in risk of diabetes-related lower limb complications, with Malays most likely to progress to DRLEC. Greater research efforts are needed to understand the aetiopathological and sociocultural processes that contribute to the higher risk of lower extremity complications among these ethnic groups.

Stroke Rehabilitation Use and Caregiver Psychosocial Health Profiles in Singapore: A Latent Profile Transition Analysis

OBJECTIVES

To identify and describe caregiver profiles based on their psychosocial health characteristics over a 12-month period and transitions among these profiles, to determine if stroke rehabilitation use at 12 months post-stroke differed by caregiver profile transition patterns, and to investigate if caregiver profiles at 3 months post-stroke moderate the association of stroke rehabilitation use at 3 months and 12 months post-stroke after accounting for covariates.

DESIGN

Latent profile transition analysis of caregiver psychosocial health with stroke rehabilitation use at 12 month post-stroke as outcome.

SETTING AND PARTICIPANTS

A total of 149 stroke patient-caregiver dyads from the Singapore Stroke Study.

METHODS

Cross-sectional latent profile analyses were conducted on caregiver psychosocial health indicators of burden, depression, health status, quality of relationship with patient, and social support. Changes in latent profile classification over 3 time points (baseline, 3 months, and 12 months post-stroke) were analyzed using latent transition analysis. A transition model with stroke rehabilitation use at 12 months post-stroke as the outcome was tested after accounting for covariates.

RESULTS

Two distinct caregiver psychosocial health latent profiles were found across time: nondistressed and distressed. Most caregivers were classified as nondistressed and remained nondistressed over time. Distressed caregivers at baseline were 76% likely to become nondistressed at 12 month post-stroke. Regardless of profile transition patterns, nondistressed caregivers at 12 months post-stroke tended to have cared for stroke rehabilitation nonusers at 12 months post-stroke. Patient depression explained profile classification at 3 months and 12 months post-stroke. After accounting for covariates, rehabilitation users at 3 months post-stroke tended to continue using rehabilitation at 12 months post-stroke only when they had nondistressed caregivers at 3 months post-stroke.

CONCLUSIONS AND IMPLICATIONS

Whether caregiver adaptation explains the associations between the latent profile transition patterns and rehabilitation use at 12 months post-stroke should be examined. Early psychosocial health assessment and sustained support should be made available to stroke caregivers to enhance their well-being and subsequent patient rehabilitation participation.

Cost-effectiveness Analysis of Breast Cancer Screening Using Mammography in Singapore: A Modeling Study

BACKGROUND

Limited research is available on the cost-effectiveness of breast cancer screening programs in Asian countries. We evaluated the cost-effectiveness of Singapore's national mammography screening program, implemented in 2002, recommending annual screening between ages 40 and 49 and biennial screening between ages 50 and 69, and alternative screening scenarios taking into account important country-specific factors.

METHODS

We used national data from Singapore in the MIcrosimulation SCreening ANalysis-Fatal diameter (MISCAN-Fadia) model to simulate 302 screening scenarios for 10 million women born between 1910 and 1969. Screening scenarios varied by starting and ending age, screening interval, and attendance. Outcome measures included life-years gained (LYG), breast cancer deaths averted, false positives, overdiagnosis, quality-adjusted life years (QALY), costs (in 2002 Singapore dollars; S$), and incremental cost-effectiveness ratios (ICER). Costs and effects were calculated and discounted with 3% using a health care provider's perspective.

RESULTS

Singapore's current screening program at observed attendance levels required 54,158 mammograms per 100,000 women, yielded 1,054 LYG, and averted 57 breast cancer deaths. At attendance rates ≥50%, the current program was near the efficiency frontier. Most scenarios on the efficiency frontier started screening at age 40. The ICERs of the scenarios on the efficiency frontiers ranged between S$10,186 and S$56,306/QALY, which is considered cost-effective at a willingness-to-pay threshold of S$70,000/QALY gained.

CONCLUSIONS

Singapore's current screening program lies near the efficiency frontier, and starting screening at age 40 or 45 is cost-effective. Furthermore, enhancing screening attendance rates would increase benefits while maintaining cost-effectiveness.

IMPACT

Screening all women at age 40 or 45 is cost-efficient in Singapore, and a policy change may be considered.

Energy conservation at an optical temporal boundary

The temporal boundary appears as a novel phenomenon in a wide range of optical devices and systems, such as the photonic crystal, metamaterials, optical microcavity, and modulator, with a dynamic medium whose refractive index changes across the boundary. However, the validation of electromagnetic energy conservation was considered in violation for the optical temporal boundary traditionally. Here a new energy space-time scheme is proposed for an optical pulse in a medium with the temporal boundary. From the Poynting theory, the electromagnetic energy is investigated based on a one-dimensional model under the assumption of impedance matching. Furthermore, the results demonstrate that a more general conservation of energy is validated in a time domain for the ideal scenario. A new invariant quantity of spatial energy in the optical medium is further obtained. The numerical results are in agreement with the theory of the temporal boundary. The conservative process of energy transportation across the optical temporal boundary is clarified and confirmed.

Integration of Primary Care with Hospital Services for Sustainable Universal Health Coverage in Singapore

Primary care services have been developed and extended, with the support of the Singapore government, in order to address the increasing needs of the aging population and noncommunicable diseases and to achieve the goal of universal health care. Though countries across the Asia Pacific aspire to achieve universal coverage, there is no set pathway. In Singapore, various service models, quality assurance methods, and financing mechanisms have been piloted and some have been scaled up. Significant effort has also gone into building links and establishing networks between hospitals and local primary care providers, including dental and allied health professionals. Several initiatives have also been introduced to support professional development, provide financial safety nets, and integrate and resource community clinics to provide family-oriented care. Social support has also been improved for isolated elderly through formalized networks linking government agencies, health providers, and community welfare groups. Ongoing challenges include integration of private providers, maintaining affordability of out-of-pocket charges, resources to meet increasing chronic disease management needs, and achieving economies of scale to sustain universal health coverage (UHC).

Risk Factors and Trends Associated With Mortality Among Adults With Hip Fracture in Singapore

IMPORTANCE

Examining trends in mortality following hip fracture and its associated factors is important for population health surveillance and for developing preventive interventions.

OBJECTIVE

To examine temporal trends in, and risk factors associated with, mortality following hip fracture over 18 years in Singapore.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, population-based cohort study included men and women aged 50 years and older admitted to Singapore hospitals for first hip fracture identified and followed up from 2000 to 2017. Demographic information, fracture type, and Charlson Comorbidity Index (CCI) score were retrieved from nationwide claims data, and mortality data were from the National Death Registry. Data were analyzed from August 2018 to December 2019.

MAIN OUTCOMES AND MEASURES

Adjusted hazard ratios (aHRs) and their 95% confidence intervals were estimated using Cox proportional hazards regression. Kaplan-Meier life table methods were used to calculate survival following the hip fracture on a cohort basis. The crude survival over time since fracture was compared by sex, age group, ethnicity, CCI, and fracture type. Standardized mortality ratios (SMRs) were calculated using all-cause mortality obtained from Singapore population life tables.

RESULTS

Among 36 082 first inpatient admissions for hip fractures (mean [SD] patient age, 78.2 [10.1] years; 24 902 [69.0%] female; 30 348 [84.1%] Chinese, 2863 [7.9%] Malay, 1778 [4.9%] Indian, and 1093 [3.0%] other ethnicity), elevated rates of mortality were observed for male sex (aHR, 1.46; 95% CI, 1.41-1.52), Malay ethnicity (aHR, 1.23; 95% CI, 1.15-1.30 vs Chinese ethnicity), older age (aHR, 5.20; 95% CI, 4.27-6.34 for age ≥85 years vs 50-54 years), high CCI score (aHR, 3.62; 95% CI, 3.42-3.84 for CCI ≥6 vs CCI of 0), trochanteric fractures (aHR, 1.11; 95% CI, 1.06-1.16 vs cervical fractures), and earlier cohorts (aHR, 0.59; 95% CI, 0.56-0.62 for 2012-2017 vs 2000-2005). Absolute mortality decreased significantly over time: by 21% in 2006 to 2011 and by 40% in 2012 to 2017, compared with 2000 to 2005. On long-term follow-up, differences in survival associated with sex and ethnicity tended to diminish, whereas differences associated with older age, higher CCI score, and trochanteric fractures increased. In the first year after fracture, reductions in SMR were observed comparing the periods 2013 to 2016 with 2003 to 2007 in women (SMR, 2.05; 95% CI, 1.91-2.20 vs SMR, 2.54; 95% CI, 2.39-2.70, respectively) but not among men (SMR, 3.28; 95% CI, 3.04-3.54 vs SMR, 3.42; 95% CI, 3.18-3.68, respectively).

CONCLUSIONS AND RELEVANCE

Malay ethnicity, older age, male sex, prefracture comorbidity, and trochanteric fractures were independently associated with increased risk of death, identifying population groups that could be targeted for intervention strategies. The improvement in relative mortality for women but not men suggests the need to develop interventions that improve mortality outcomes for men.

Risk Prediction Scores for Mortality, Cerebrovascular, and Heart Disease Among Chinese People With Type 2 Diabetes

CONTEXT

Risk scores for cardiovascular and mortality outcomes have not been commonly applied in Chinese populations.

OBJECTIVE

To develop and externally validate a set of parsimonious risk scores [University of Hong Kong-Singapore (HKU-SG)] to predict the risk of mortality, cerebrovascular disease, and ischemic heart disease among Chinese people with type 2 diabetes and compare HKU-SG risk scores to other existing ones.

DESIGN

Retrospective population-based cohorts drawn from Hong Kong Hospital Authority health records from 2006 to 2014 for development and Singapore Ministry of Health records from 2008 to 2016 for validation. Separate five-year risk scores were derived using Cox proportional hazards models for each outcome.

SETTING

Study participants were adults with type 2 diabetes aged 20 years or over, consisting of 678,750 participants from Hong Kong and 386,425 participants from Singapore.

MAIN OUTCOME MEASURES

Performance was evaluated by discrimination (Harrell C-index), and calibration plots comparing predicted against observed risks.

RESULTS

All models had fair external discrimination. Among the risk scores for the diabetes population, ethnic-specific risk scores (HKU-SG and Joint Asia Diabetes Evaluation) performed better than UK Prospective Diabetes Study and Risk Equations for Complications Of type 2 Diabetes models. External validation of the HKU-SG risk scores for mortality, cerebrovascular disease, and ischemic heart disease had corresponding C-indices of 0.778, 0.695, and 0.644. The HKU-SG models appeared well calibrated on visual plots, with predicted risks closely matching observed risks.

CONCLUSIONS

The HKU-SG risk scores were developed and externally validated in two large Chinese population-based cohorts. The parsimonious use of clinical predictors compared with previous risk scores could allow wider implementation of risk estimation in diverse Chinese settings.

Dyadic approach to post-stroke hospitalizations: role of caregiver and patient characteristics

Aim

To study the association of caregiver factors and stroke patient factors with rehospitalizations over the first 3 months and subsequent 3–12 months post-stroke in Singapore.

Methods

Patients with stroke and their caregivers were recruited in the Singapore Stroke Study, a prospective yearlong cohort. While caregiver and patient variables were taken from this study, hospitalization data were extracted from the national claims database. We used Poisson modelling to perform bivariate and multivariable analysis with counts of hospitalization as the outcome.

Results

Two hundred and fifty-six patient with stroke and caregiver dyads (N = 512) were analysed, with patients having spouse (60%), child (29%), sibling (4%) and other (7%) as their caregivers. Among all participants, 89% of index strokes were ischemic, 57% were mild in severity and more than half (59%) of the patients had moderate or severe disability post-stroke as measured on the Modified Rankin Scale. Having social support in the form of a foreign domestic worker for general help of caregiver reduced the hospitalization rate over 3 months post-stroke by 66% (IRR: 0.342; 95% CI: 0.180, 0.651). Compared to having a spousal caregiver, those with a child caregiver had an almost three times greater rate of hospitalizations over 3–12 months post-stroke (IRR: 2.896; 95% CI: 1.399, 5.992). Higher reported caregiving burden at the 3-month point was associated with the higher subsequent rate of hospitalization.

Conclusion

Recommendations include the adoption of a dyadic or holistic approach to post-stroke care provision by healthcare practitioners, giving due importance to both patients with stroke and their caregivers, integrating caregivers in the healthcare system to extend the care continuum to include informal care in the community and provision of timely support for caregivers.

Hip fractures in Singapore: ethnic differences and temporal trends in the new millennium

Despite an increase in absolute numbers, the age-standardized incidence of hip fractures in Singapore declined in the period 2000 to 2017. Among the three major ethnic groups, Chinese women had the highest fracture rates but were the only group to show a temporal decline.

INTRODUCTION

A study published in 2001 predicted a 30-50% increase in Singapore hip fracture incidence rates over the ensuing 30 years. To test that prediction, we examined the incidence of hip fracture in Singapore from 2000 to 2017.

METHODS

We carried out a population-based study of hip fractures among Singapore residents aged ≥ 50 years. National medical insurance claims data were used to identify admissions with a primary discharge diagnosis of hip fracture. Age-adjusted rates, based on the age distribution of the Singapore population of 2000, were analyzed separately by sex and ethnicity (Chinese, Malay, or Indian).

RESULTS

Over the 18-year study period, 36,082 first hip fractures were recorded. Total hip fracture admissions increased from 1487 to 2729 fractures/year in the years 2000 to 2017. Despite this absolute increase, age-adjusted fracture rates declined, with an average annual change of - 4.3 (95% CI - 5.0, - 3.5) and - 1.1 (95% CI - 1.7, - 0.5) fractures/100,000/year for women and men respectively. Chinese women had 1.4- and 1.9-fold higher age-adjusted rates than Malay and Indian women: 264 (95% CI 260, 267) versus 185 (95% CI 176, 193) and 141 (95% CI 132, 150) fractures/100,000/year, respectively. Despite their higher fracture rates, Chinese women were the only ethnic group exhibiting a decline, most evident in those ≥ 85 years, in age-adjusted fracture rate of - 5.3 (95% CI - 6.0, - 4.5) fractures/100,000/year.

CONCLUSION

Although the absolute number of fractures increased, steep drops in elderly Chinese women drove a reduction in overall age-adjusted hip fracture rates. Increases in the older population will lead to a rise in total number of hip fractures, requiring budgetary planning and new preventive strategies.

The Long-Term Impact of Functional Disability on Hospitalization Spending in Singapore

Singapore is one of the fastest-aging populations due to increased life expectancy and lowered fertility. Lifestyle changes increase the burden of chronic diseases and disability. These have important implications for social protection systems. The goal of this paper is to model future functional disability and healthcare expenditures based on current trends. To project the health, disability and hospitalization spending of future elders, we adapted the Future Elderly Model (FEM) to Singapore. The FEM is a dynamic Markov microsimulation model developed in the US. Our main source of population data was the Singapore Chinese Health Study (SCHS) consisting of 63,000 respondents followed up over three waves from 1993 to 2010. The FEM model enables us to investigate the effects of disability compounded over the lifecycle and hospitalization spending, while adjusting for competing risk of multi-comorbidities. Results indicate that by 2050, 1 in 6 elders in Singapore will have at least one ADL disability and 1 in 3 elders will have at least one IADL disability, an increase from 1 in 12 elders and 1 in 5 elders respectively in 2014. The highest prevalence of functional disability will be in those aged 85 years and above. Lifetime hospitalization spending of elders aged 55 and above is US$24,400 (30.2%) higher among people with functional disability compared to those without disability. Policies that successfully tackle diabetes and promote healthy living may reduce or delay the onset of disability, leading to potential saving. In addition, further technological improvements may reduce the financial burden of disability.

Disseminated Cutaneous Trichosporonosis in an Adult Bone Marrow Transplant Patient

The Trichosporon species are yeast-like opportunistic pathogens in immunocompromised patients. Trichosporon asahii infections have been reported in pediatric bone marrow transplant (BMT) patients. However, its incidence is low in the adult literature. A 52-year-old Chinese woman who was diagnosed with acute myeloid leukemia received induction chemotherapy and underwent allogenic bone marrow transplant, which was complicated by a relapse and required salvage chemotherapy. She developed persistent non-neutropenic fever secondary to presumed hepatosplenic candidiasis. Antifungal therapy with fluconazole and anidulafungin was administered. She remained febrile and tender dusky nodules appeared over all the four limbs. Histopathological examination and fungal culture identified T. asahii. Oral voriconazole was initiated with complete resolution of her lesions. The Trichosporon species is a frequently isolated yeast species from cancer patients. Voriconazole has become the first choice agent against Trichosporon. We highlight the increased awareness and clinical suspicion required for diagnosis and subsequent management in similar adult patients.

A Cost-Effectiveness Analysis of Surgery for Middle-Aged Men with Severe Obstructive Sleep Apnea Intolerant of CPAP

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. Conventional OSA therapy necessitates indefinite continuous positive airway pressure (CPAP). Although CPAP is an effective treatment modality, up to 50% of OSA patients are intolerant of CPAP. We explore whether surgical modalities developed for those intolerant of CPAP are cost-effective.

METHODS

We construct a lifetime semi-Markov model of OSA that accounts for observed increased risks of stroke, cardiovascular disease, and motor vehicle collisions for a 50-year-old male with untreated severe OSA. Using this model, we compare the cost-effectiveness of (1) no treatment, (2) CPAP only, and (3) CPAP followed by surgery (either palatopharyngeal reconstructive surgery [PPRS] or multilevel surgery [MLS]) for those intolerant to CPAP.

RESULTS

Compared with the CPAP only strategy, CPAP followed by PPRS (CPAP-PPRS) adds 0.265 quality adjusted life years (QALYs) for an increase of $2,767 (discounted 2010 dollars) and is highly cost effective with an incremental cost-effectiveness ratio (ICER) of $10,421/QALY for a 50-year-old male with severe OSA. Compared to a CPAP-PPRS strategy, the CPAP-MLS strategy adds 0.07 QALYs at an increase of $6,213 for an ICER of $84,199/QALY. The CPAP-PPRS strategy appears cost-effective over a wide range of parameter estimates.

CONCLUSIONS

Palatopharyngeal reconstructive surgery appears cost-effective in middle-aged men with severe OSA intolerant of CPAP. Further research is warranted to better define surgical candidacy as well as short-term and long-term surgical outcomes.

COMMENTARY

A commentary on this article appears in this issue on page 509.

In vivo and in vitro studies on the roles of neutrophil extracellular traps during secondary pneumococcal pneumonia after primary pulmonary influenza infection

Seasonal influenza virus infections may lead to debilitating disease, and account for significant fatalities annually worldwide. Most of these deaths are attributed to the complications of secondary bacterial pneumonia. Evidence is accumulating to support the notion that neutrophil extracellular traps (NETs) harbor several antibacterial proteins, and trap and kill bacteria. We have previously demonstrated the induction of NETs that contribute to lung tissue injury in severe influenza pneumonia. However, the role of these NETs in secondary bacterial pneumonia is unclear. In this study, we explored whether NETs induced during pulmonary influenza infection have functional significance against infections with Streptococcus pneumoniae and other bacterial and fungal species. Our findings revealed that NETs do not participate in killing of Streptococcus pneumoniae in vivo and in vitro. Dual viral and bacterial infection elevated the bacterial load compared to animals infected with bacteria alone. Concurrently, enhanced lung pathogenesis was observed in dual-infected mice compared to those challenged with influenza virus or bacteria alone. The intensified NETs in dual-infected mice often appeared as clusters that were frequently filled with partially degraded DNA, as evidenced by punctate histone protein staining. The severe pulmonary pathology and excessive NETs generation in dual infection correlated with exaggerated inflammation and damage to the alveolar-capillary barrier. NETs stimulation in vitro did not significantly alter the gene expression of several antimicrobial proteins, and these NETs did not exhibit any bactericidal activity. Fungicidal activity against Candida albicans was observed at similar levels both in presence or absence of NETs. These results substantiate that the NETs released by primary influenza infection do not protect against secondary bacterial infection, but may compromise lung function.

Variation in nephrologist visits to patients on hemodialysis across dialysis facilities and geographic locations

BACKGROUND AND OBJECTIVES

Geographic and other variations in medical practices lead to differences in medical costs, often without a clear link to health outcomes. This work examined variation in the frequency of physician visits to patients receiving hemodialysis to measure the relative importance of provider practice patterns (including those patterns linked to geographic region) and patient health in determining visit frequency.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This work analyzed a nationally representative 2006 database of patients receiving hemodialysis in the United States. A variation decomposition analysis of the relative importance of facility, geographic region, and patient characteristics--including demographics, socioeconomic status, and indicators of health status--in explaining physician visit frequency variation was conducted. Finally, the associations between facility, geographic and patient characteristics, and provider visit frequency were measured using multivariable regression.

RESULTS

Patient characteristics accounted for only 0.9% of the total visit frequency variation. Accounting for case-mix differences, patients' hemodialysis facilities explained about 24.9% of visit frequency variation, of which 9.3% was explained by geographic region. Visit frequency was more closely associated with many facility and geographic characteristics than indicators of health status. More recent dialysis initiation and recent hospitalization were associated with decreased visit frequency.

CONCLUSIONS

In hemodialysis, provider visit frequency depends more on geography and facility location and characteristics than patients' health status or acuity of illness. The magnitude of variation unrelated to patient health suggests that provider visit frequency practices do not reflect optimal management of patients on dialysis.

Proliferating tricholemmal tumour: clinicopathological aspects of a case

We report the case of a 49-year-old man who presented with an enlarging mass over his occipital scalp. The clinical impression was either a squamous cell carcinoma or an unusual adnexal tumour. A wide excision was performed with skin grafting. Gross examination revealed a large exophytic tumour mass measuring 10 cm. Histopathological examination showed a circumscribed, well-differentiated squamoproliferative lesion with a lobulated architecture. Clear cell features, pilar-type keratinisation, microcalcifications and the presence of mucinous degeneration were noted. A diagnosis of proliferating tricholemmal tumour was made. This entity incorporates a spectrum of lesions, ranging from the mostly benign proliferating tricholemmal cyst to tumours having more atypical cellular and invasive features, the latter features correlating with an increased capacity for aggressive behaviour. Management-wise, such tumours require complete excision with follow-up. As the tumours are often large in size at presentation, reconstruction is required.

Multiple idiopathic cervical resorption: case report and discussion of management options

AIM

To present a case of cervical root resorption affecting all teeth and resulting in multiple tooth loss.

SUMMARY

A healthy 33-year-old Chinese male, with no contributory medical or family/social history, presented with generalized cervical root resorption. Lesions varied in severity amongst teeth and even involved an impacted third molar. All cervical root surfaces were affected and lesions often extended coronally, undermining enamel. CBCT demonstrated that the lesions were more extensive and more widely distributed than was seen using conventional radiography. Bone extended into many resorptive defects but without clinical evidence of ankylosis. Periodontal probing, pulp testing, percussion sound and mobility were within normal limits. Key learning points  • Aetiology of the generalized idiopathic cervical root resorption is uncertain. • Management is complex, and options have included surgical exposure and restoration of affected sites, extraction and submergence of affected roots. • A staged approach involving early intervention with restoration of resorptive defects, followed by progressive extraction and replacement with implant-supported prostheses is recommended.

Gastroschisis and omphalocele in Singapore: a ten-year series from 1993 to 2002

INTRODUCTION

Two of the most common malformations of the anterior abdominal wall include gastroschisis and omphalocele, both of which are associated with high morbidity and mortality. Studies have shown an increase in both conditions worldwide. These two conditions are considered separate entities because of their differences in epidemiology, physical characteristics and associations with other structural anomalies and chromosomal aberrations. This is the first local study to examine these two conditions.

METHODS

Data of anterior abdominal wall defect cases of patients born during the period 1993-2002 were retrieved from the National Birth Defects Registry and analysed.

RESULTS

There were a total of 121 cases of anterior abdominal wall defects in the ten-year period from 1993 to 2002, giving an overall incidence of 2.63 per 10,000 livebirths. The individual incidences of gastroschisis (n = 21) and omphalocele (n = 100) were 0.46 and 2.17 per 10,000 livebirths, respectively. 33 percent of women with foetal gastroschisis were younger than 25 years of age, and 31 percent of women with foetal omphalocele were older than 35 years of age. This was statistically significant when compared to the general obstetric population. Incidence of omphalocele was lowest among the Indian population. Total aneuploidy rate was 14.9 percent (18/121 cases), with omphalocele having a higher aneuploidy rate than gastroschisis (17 percent versus 4.8 percent). Omphaloceles are also more likely to be associated with cardiac defects (p-value equals 0.02).

CONCLUSION

Our studies are consistent with the worldwide trend of an increasing prevalence of anterior abdominal wall defects. The race-specific differences suggest genetic and environmental factors that warrant further studies.

Myelolipoma within a non-functional adrenal cortical adenoma

Myelolipoma within an adrenal cortical adenoma is a very rare cause of adrenal incidentaloma, and only nine cases have been reported in the English and Japanese literature. We report a 66-year-old Chinese man, with a history of hypertension and hyperlipidaemia, who presented with lower limb oedema and had a computed tomography (CT ) of the abdomen done to exclude intra-abdominal mass. His lower limb symptoms resolved after switching his antihypertensive medication. CT of the abdomen showed a large heterogeneously-enhancing mass in the left suprarenal region, measuring 72 mm by 55 mm. Clinical history, physical examination and laboratory results did not show any evidence to suggest metabolic disorder such as Cushing's syndrome, hyperaldosteronism or catecholamine hypersecretion. The patient underwent a left adrenalectomy, and a histopathological study confirmed the mass to be a non-functional adrenal cortical adenoma containing myelolipoma. The patient was well postoperatively and was discharged uneventfully. To the best of our knowledge, this is the first non-functional adrenal cortical adenoma reported; in the nine cases of myelolipoma within an adrenal cortical adenoma reported previously, all the patients had Cushing's syndrome. The literature on synchronous myelolipoma with adrenal adenoma, and myelolipoma within functional adrenal adenoma, is reviewed.

Celecoxib reduces microvessel density in patients treated with nasopharyngeal carcinoma and induces changes in gene expression

BACKGROUND

Celecoxib is a selective cyclooxygenase-2 inhibitor with antitumor and antiangiogenic activity. We sought to determine pharmacodynamic change in tumors of patients with nasopharyngeal carcinoma (NPC) treated with celecoxib.

METHODS

Tumor biopsies were obtained before and after treatment with celecoxib 400 mg b.i.d. for 14 days in patients with newly diagnosed, untreated NPC. Tumor angiogenesis and cell proliferation were assessed by immunohistochemistry and gene expression by microarray analysis. Plasma celecoxib concentrations were obtained on days 8 and 14.

RESULTS

Paired samples were analyzed in 15 patients. Microvessel density was reduced in post-treatment samples and mean celecoxib levels reached therapeutic levels. Thirty-five genes (27 down-regulated, eight up-regulated) were differentially expressed on microarray analysis (p < 0.001). Down-regulated genes included cell cycle regulation-related (cyclin-dependent kinase 2, YES1), transcription factor (TRIP-Br2), whereas the antigen processing and presentation-related gene HLA-DM B was up-regulated.

CONCLUSION

Celecoxib reduced angiogenesis and induced tumor transcriptional changes. Further characterization of these transcriptional changes in vivo is needed to provide further insights into the effects of celecoxib in neoplastic tissue. Our findings provide a rationale for clinical studies aimed at assessing the efficacy of celecoxib in the treatment of NPC.

Metastatic testicular carcinoma from the colon with clinical, immunophenotypical, and molecular characterization: report of a case

We report a case of testicular metastasis from a colonic adenocarcinoma. The presentation of testicular metastasis, diagnosis, management, and possible modes of spread are reported. In addition to conventional investigations and histopathologic techniques, a molecular study of the testicular metastasis and colon primary, using microsatellite analysis, was performed to confirm the primary origin. Its potential uses are discussed.

Uncommon benign intrascrotal tumours

INTRODUCTION

Benign intrascrotal tumours are rare.

CLINICAL PICTURE

Three patients with bilateral paratesticular leiomyomas, an adenomatoid tumour of the testis and a left paratesticular dermoid cyst coexisting with a synchronous left paratesticular epidermal cyst are presented. These tumours were discrete, hard and smooth lesions, in which the diagnosis of malignancy could not be safely excluded preoperatively even with ultrasonography.

TREATMENT AND OUTCOME

The first patient had orchiectomy with contralateral testicular preserving surgery, the second patient underwent orchiectomy and the third had conservative testicular surgery.

CONCLUSION

Awareness of these benign tumours may allow for testicular preservation.

Cervical cytology: an audit in a Singapore teaching hospital

OBJECTIVES

To describe the cervical cytology diagnoses and cyto-histological correlation in the Department of Pathology, National University of Singapore in 1997 and to compare the data with international figures.

METHODS

A database search of all cervical cytology cases diagnosed in the department in 1997 as well as follow-up biopsies was carried out. The data was then critically analysed.

RESULTS

10,207 cases were reviewed. 96% of the cases had a diagnosis of "negative". Under 1% of cases were labelled as "inadequate". "Atypia" was diagnosed in 1% and dysplasia and/or malignancy was diagnosed in 1%. These figures correlate well with international data. Of the dysplasia cases, 78% were followed by biopsy. Of the high-grade dysplasia cases that were biopsied, 97% of the biopsy diagnoses were within the acceptable concordance range with the cytology diagnoses and in only 3% was there a significant discrepancy. Of the cases diagnosed as atypia, 39% were subsequently biopsied at the same institution as the next procedure and only one showed high grade dysplasia. A total of six cases showed a significant discrepancy between the cervical cytology result and the subsequent biopsy diagnosis and these were reviewed to elucidate the reasons for the discrepancies.

CONCLUSION

The cervical cytology service is of a high diagnostic standard. A subset of patients is probably being prematurely biopsied and may benefit from having a repeat smear instead. Specific clinical protocols regarding subsequent therapy following cytology results and closer cyto-histological correlation are two main areas where the cytology service can be improved.

Audit of transthoracic fine needle aspiration of the lung: cytological subclassification of bronchogenic carcinomas and diagnosis of tuberculosis

INTRODUCTION

Transthoracic fine-needle aspiration cytology (FNAC) is a useful tool for evaluating neoplastic and inflammatory lung nodules. In view of the relative paucity of published audit studies regionally, such a study was undertaken to assess the use of the technique in our centre.

METHODS

One hundred and fourteen FNACs were performed during 1997-1999. Immediate assessment for specimen adequacy was done. Diagnoses were correlated with clinical-pathological information and selective blind review performed.

RESULTS

Cytologically, 65.8% of cases were malignant, 1.8% were atypical, 25.4% were inflammatory/non-malignant and 7% were inadequate. Cytological-histological tumour diagnostic concordance was 94.4%. Diagnostic sensitivity for malignancy: 93.4%, specificity: 95.8%, accuracy: 94%. Eight inadequate/ benign cases (7%) proved to be malignant with clinical-pathological follow-up. Tuberculosis was confirmed (acid-fast bacilli detected) in six cases (5.3%) and suggested in a further 10 cases (8.8%). The cytological review showed 96% concordance with the original benign/malignant diagnoses. Pneumothorax rate was 18%.

CONCLUSION

FNAC is an accurate and safe method for the evaluation of lung nodules and it enables subclassification of bronchogenic carcinomas in the vast majority of cases. It is also useful for the diagnosis of tuberculous pulmonary nodules. Immediate assessment optimises specimen adequacy; inadequate/non-malignant smears in particular, need clinical correlation, close follow-up and re-biopsy, if necessary.

Expression pattern of human P2Y receptor subtypes: a quantitative reverse transcription-polymerase chain reaction study

The diverse biological actions of extracellular nucleotides in tissues and cells are mediated by two distinct classes of P2 receptor, P2X and P2Y. The G protein-coupled P2Y receptors comprise at least six mammalian subtypes (P2Y(1,2,4,6,11,12)), all of which have been cloned from human tissues, as well as other species. The P2Y receptor subtypes differ in their pharmacological selectivity for various adenosine and uridine nucleotides, which overlap in some cases. Data concerning the mRNA expression patterns of five P2Y receptors (P2Y(1,2,4,6,11)) in different human tissues and cells are currently quite limited, while P2Y mRNA distribution in the human brain has not previously been studied. In this study, we have addressed this deficiency in receptor expression data by using a quantitative reverse transcription-polymerase chain reaction approach to measure the precise mRNA expression pattern of each P2Y receptor subtype in a number of human peripheral tissues and brain regions, from multiple individuals, as well as numerous human cell lines and primary cells. All five P2Y receptors exhibited widespread yet subtype-selective mRNA expression profiles throughout the human tissues, brain regions and cells used. Our extensive expression data indicate the many potentially important roles of P2Y receptors throughout the human body, and will help in elucidating the physiological function of each receptor subtype in a wide variety of human systems.

Application of finite element analysis in implant dentistry: a review of the literature

Finite element analysis (FEA) has been used extensively to predict the biomechanical performance of various dental implant designs as well as the effect of clinical factors on implant success. By understanding the basic theory, method, application, and limitations of FEA in implant dentistry, the clinician will be better equipped to interpret results of FEA studies and extrapolate these results to clinical situations. This article reviews the current status of FEA applications in implant dentistry and discusses findings from FEA studies in relation to the bone-implant interface, the implant-prosthesis connection, and multiple-implant prostheses.

Implant-abutment screw joint preload of 7 hex-top abutment systems

This study measured the screw joint preload of the implant-abutment interface for 7 common hex-top abutment systems. Increasingly, prosthetic designs are utilizing a direct prosthetic connection to the implant, placing the implant-abutment screw joint under direct functional loads and moments. Sufficiently high screw joint preloads are required to maintain screw joint integrity and confer clinical longevity to implant prosthetic components to prevent such complications as abutment screw loosening and screw fracture. Strain-gauged abutment load cells were calibrated to measure screw joint pre-load at the implant-abutment interface. Torque delivery by electronic torque controller was varied at low- and high-speed settings. At manufacturer's recommended torques, the overall mean preload measured was 181.6 +/- 60.0 N for the Nobel Biocare Standard abutment, 291.3 +/- 41.2 N for the Nobel Biocare EsthetiCone abutment, 456.5 +/- 44.0 N for the Nobel Biocare MirusCone abutment, 369.7 +/- 32.9 N for the 3i Titanium Abutment post, 643.4 +/- 143.1 N for the Nobel Biocare CeraOne abutment, 536.3 +/- 68.6 N for the Nobel Biocare "Gold Cylinder to Fixture" abutment, and 556.9 +/- 145.6 N for the Nobel Biocare TiAdapt abutment. Analysis of variance revealed significant differences between abutment systems (P < .001) and between torque driver speed settings (P < .001). Implant-abutment screw joint preload of external-hex implants is dependent on abutment design, screw diameter, material, tightening torque, and torque controller speed.

Pseudo-outer product based fuzzy neural network fingerprint verification system

Fingerprint identification has been used in law enforcement applications over the last century, and has become the de facto international standard for positive identification. With the emergence of automated fingerprint identification technologies, it has assisted in making the once labour-intensive process of classifying, searching and matching a thing of the past. As a biometrics proof of identification, not many have ventured into the world of fingerprint identification using fuzzy neural networks. In this paper, a database of fingerprint images is constructed and a fuzzy neural network called the pseudo outer product fuzzy neural network (POPFNN) [Zhou, R.W. & Quek, C. (1996). A pseudo outer-product based fuzzy neural network. Neural Networks, 9(9), 1569-1581] is trained to detect similarity between two fingerprints and decide whether they belong to the same person. The fundamental idea is that, given a person's fingerprints taken under different conditions, the POPFNN based fingerprint verification system should be sufficiently robust to distinguish the difference. The people providing the fingerprint samples are subjected to different 'adverse' conditions; from wetness to chemical treatments. Fingerprint images are taken after conditions such as: after a shower, holding pineapples (mild acid from fruit), after washing one's hands, etc. The characteristics of POPFNN, such as the learning, generalisation, and high computational abilities, make fingerprint verification particularly powerful when verifying authentic fingerprints subjected to external conditions and recognising spurious ones. In order to demonstrate the efficacy of POPFNN and its application in the fingerprint verification system (FVS), several types of experiments have been designed and implemented in this work. The experimental results and analysis are presented at the end of the paper for discussion.

Cloning, expression, and pharmacological characterization of a novel human histamine receptor

Using a genomics-based reverse pharmacological approach for screening orphan G-protein coupled receptors, we have identified and cloned a novel high-affinity histamine receptor. This receptor, termed AXOR35, is most closely related to the H3 histamine receptor, sharing 37% protein sequence identity. A multiple responsive element/cyclic AMP-responsive element-luciferase reporter assay was used to identify histamine as a ligand for AXOR35. When transfected into human embryonic kidney 293 cells, the AXOR35 receptor showed a strong, dose-dependent calcium mobilization response to histamine and H3 receptor agonists including imetit and immepip. Radioligand binding confirmed that the AXOR35 receptor was a high-affinity histamine receptor. The pharmacology of the AXOR35 receptor was found to closely resemble that of the H3 receptor; the major difference was that (R)-alpha-methylhistamine was a low potency agonist of the AXOR35 receptor. Thioperamide is an antagonist at AXOR 35. Expression of AXOR35 mRNA in human tissues is highest in peripheral blood mononuclear cells and in tissues likely to contain high concentrations of blood cells, such as bone marrow and lung. In situ hybridization analysis of a wide survey of mouse tissues showed that mouse AXOR35 mRNA is selectively expressed in hippocampus. The identification and localization of this new histamine receptor will expand our understanding of the physiological and pathological roles of histamine and may provide additional opportunities for pharmacological modification of these actions.

On-line computerized diagnosis of pain-related disability and psychological status of TMD patients: a pilot study

Temporomandibular disorders (TMD) is a collective term embracing a number of clinical problems, which involve the masticatory musculature, the temporomandibular joint or both. Virtually all theories dealing with the aetiology and treatment of TMD have recognized the importance of psychological factors. This paper reports the development of a computerized on-line program (NUS TMD v1.1) for the diagnosis of pain-related disability and psychological status of TMD patients based on Axis II of the research diagnostic criteria (RDC)/TMD (Dworkin, S.F. & LeResche, L. 1992. Journal of Craniomandibular Disorders: Facial Oral Pain, 6, 301), which was developed to redress the lack of diagnostic criteria in TMD research. Methods adopted by RDC/TMD for use in assessing Axis II status include a seven-item questionnaire for grading chronic pain severity, the Symptom Checklist 90 Revised (SCL-90-R) and a jaw disability checklist. A pilot study, based on 37 new TMD patient records, was conducted to study the pain-related disability and psychological status of TMD patients using this newly developed program. The mean age of the predominantly Chinese population (86.5%) was 32.19 years (range 20-72 years) with a sex distribution of 24 females and 13 males. Most patients (78%) had low disability, with 12 patients having low intensity and 17 patients having high intensity pain. Approximately 73% of the sample population were moderately or severely depressed. Patients that were moderately and severely depressed had significantly higher scores for limitation related to mandibular functioning than normal patients. The three most frequent jaw disabilities were: eating hard foods (84%), yawning (78%) and chewing (65%).

Influence of water exposure on three-body wear of composite restoratives

The objective of this investigation was to study the influence of water exposure on the three-body wear of composite restoratives. A three-body wear instrumentation was used to investigate the wear resistance of five composite restoratives [Silux Plus (SX), Z100 (ZO), Ariston pHc (AR), Surefil (SF) and Tetric Ceram (TC)] with and without exposure to water. An amalgam alloy [Dispersalloy (DA)] was used as control. Ten specimens were made for each material. The specimens were conditioned in artificial saliva at 37 degrees C for 24 h and randomly divided into two groups of 5. The first group was subjected to wear testing immediately after the 24 h conditioning period, while the second group was conditioned in distilled water at 37 degrees C for 7 days prior to wear testing. All materials were wear tested at 15 N contact force against SS304 counter-bodies for 20,000 cycles with millet seed slurry as third-body. Wear depth (microm) was measured using profilometry, and results were analyzed by ANOVA/Scheffe's and independent sample t-tests at significance level 0.05. Ranking of wear resistance was as follows: without water exposure: DA > ZO > SF > AR > SX > TC; with water exposure: DA > ZO > SX > SF > AR > TC. Wear factor ranged from 2.20 for ZO to 7.13 for TC without water exposure and from 46.00 for ZO to 143.00 for TC with exposure to water. Exposure to water significantly increased three-body wear for all composite restoratives, but did not affect wear of the amalgam alloy. The effects of water exposure must be considered for the evaluation of wear in all polymeric composite restoratives.

Receptor for the pain modulatory neuropeptides FF and AF is an orphan G protein-coupled receptor

Opiate tolerance and dependence are major clinical and social problems. The anti-opiate neuropeptides FF and AF (NPFF and NPAF) have been implicated in pain modulation as well as in opioid tolerance and may play a critical role in this process, although their mechanism of action has remained unknown. Here we describe a cDNA encoding a novel neuropeptide Y-like human orphan G protein-coupled receptor (GPCR), referred to as HLWAR77 for which NPAF and NPFF have high affinity. Cells transiently or stably expressing HLWAR77 bind and respond in a concentration-dependent manner to NPAF and NPFF and are also weakly activated by FMRF-amide (Phe-Met-Arg-Phe-amide) and a variety of related peptides. The high affinity and potency of human NPFF and human NPAF for HLWAR77 strongly suggest that these are the cognate ligands for this receptor. Expression of HLWAR77 was demonstrated in brain regions associated with opiate activity, consistent with the pain-modulating activity of these peptides, whereas the expression in adipose tissue suggests other physiological and pathophysiological activities for FMRF-amide neuropeptides. The discovery that the anti-opiate neuropeptides are the endogenous ligands for HLWAR77 will aid in defining the physiological role(s) of these ligands and facilitate the identification of receptor agonists and antagonists.

Identification of an EDG7 variant, HOFNH30, a G-protein-coupled receptor for lysophosphatidic acid

We have identified a cDNA, designated HOFNH30, which encodes a 354 amino acid G-protein-coupled receptor (GPCR). This receptor has 96% amino acid identity to the Jurkat-T cell-derived EDG7 and could be a splice variant. RT-PCR analysis demonstrated that HOFNH30 mRNA is expressed in placenta whereas EDG7 mRNA shows highest expression in prostate. The HOFNH30 gene is localized to human chromosome 1p22. 3-1p31.1. When HOFNH30 was expressed in RBL-2H3 cells, LPA and phosphatidic acid (PA) induced a calcium mobilization response with EC(50) values of 13 nM and 3 microM, respectively. LPA also induced phosphorylation of mitogen-activated protein kinase (p42(MAPK) and p44(MAPK)) in HOFNH30-transfected but not vector-transfected RBL-2H3 cells. In the present study, we have identified a novel variant from the EDG receptor family, a GPCR for which LPA is a high-affinity endogenous ligand.

Identification of SAF-2, a novel siglec expressed on eosinophils, mast cells, and basophils

BACKGROUND

Eosinophils, basophils, and mast cells are believed to be the central tenet cells in allergic conditions including allergic rhinitis, asthma, and eczema. The molecular mechanisms underlying the recruitment of these cells to sites of allergic inflammation are poorly understood.

OBJECTIVES

Our aim was to identify a common adhesion molecule that could potentially be responsible for mediating the recruitment of the allergic cell types to the lungs and other sites of allergy.

METHODS

We have cloned a sialoadhesin molecule from a human eosinophil library with the use of expressed sequence tag technology and characterized its expression on allergic cells by the use of flow cytometry and specific mAbs.

RESULTS

With the use of expressed sequence tag sequencing, we have identified a novel siglec molecule, SAF-2. SAF-2 has homology with other sialoadhesin family members (CD33 and siglec-5) and belongs to a subgroup of the Ig superfamily. SAF-2 is a 431-amino acid protein composed of 3 Ig domains with a 358-amino acid extracellular domain and a 47-amino acid tail. SAF-2 is highly restricted to eosinophils, basophils, and mast cells. Antibodies to SAF-2 do not modulate Ca(++) mobilization or chemotaxis of human eosinophils induced by eotaxin.

CONCLUSION

SAF-2 is a highly restricted sialoadhesin molecule, which may be useful in the detection and/or modulation of allergic cells.

Identification and cloning of a human urea transporter HUT11, which is downregulated during adipogenesis of explant cultures of human bone

Bipotential cells in human trabecular bone explant cultures that express osteoblast characteristics are able to undergo adipogenesis in the presence of 3-isobutyl-1-methylxanthine plus dexamethasone (Nuttall et al. [1998] J Bone Miner Res 13:371-382). The initial studies of these bipotential cells in explant cultures have been extended to examine differential gene expression during osteoblast/adipocyte transdifferentiation. Using differential display, we have identified a gene expressed in trabecular bone explant cultures that is downregulated as these cells differentiate from an osteoblast to an adipocyte phenotype. Homology searching identified this gene as the human urea transporter HUT11. The expression and downregulation of HUT11 have been observed in multiple patient bone explant cultures. The size of the bone explant-derived HUT11 mRNA is approximately 4.4 kb, which is identical to the largest splice variant reported. In this article, we report the cloning and sequencing of this gene from primary human osteoblasts. In addition, we report tissue distribution for the bone explant-derived form of HUT11 mRNA and show a reciprocal relationship between the expression of HUT11 and the nuclear hormone receptor peroxisome proliferator-activated receptor gamma 2, which is a marker of adipocyte differentiation. Because the control of osteoblast/adipocyte transdifferentiation is unknown, selective downregulation of HUT11 during adipogenesis suggests that HUT11 expression may be a marker of the switch from an osteoblast to an adipocyte phenotype. Understanding the role of HUT11 in osteoblasts may provide insights into the mechanism controlling osteoblast and adipocyte differentiation.

Herpesvirus entry mediator ligand (HVEM-L), a novel ligand for HVEM/TR2, stimulates proliferation of T cells and inhibits HT29 cell growth

Herpesvirus entry mediator (HVEM), a member of the tumor necrosis factor (TNF) receptor family, mediates herpesvirus entry into cells during infection. Upon overexpression, HVEM activates NF-kappaB and AP-1 through a TNF receptor-associated factor (TRAF)-mediated mechanism. Using an HVEM-Fc fusion protein, we screened soluble forms of novel TNF-related proteins derived from an expressed sequence tag data base. One of these, which we designated HVEM-L, specifically bound to HVEM-Fc with an affinity of 44 nM. This association was confirmed with soluble and membrane forms of both receptor and ligand. HVEM-L mRNA is expressed in spleen, lymph nodes, macrophages, and T cells and encodes a 240-amino acid protein. A soluble, secreted form of the protein stimulates proliferation of T lymphocytes during allogeneic responses, inhibits HT-29 cell growth, and weakly stimulates NF-kappaB-dependent transcription.

A novel human bone marrow stroma-derived cell line TF274 is highly osteogenic in vitro and in vivo

A novel, immortalized, human bone marrow stroma-derived cell line TF274 is described which has the ability to form bone both in vitro and in vivo. Under basal conditions these cells expressed alkaline phosphatase (ALP) and type I collagen genes which are characteristic of the osteoblast phenotype. ALP levels were upregulated in the presence of osteotropic agents such as parathyroid hormone (PTH), transforming growth factor beta (TGF-beta), and BMP-2. In addition, PTH also increased cAMP levels in these cells. The capacity of these cells to form bone in vitro was evaluated by culturing them in the presence of L-ascorbic acid and beta-glycerophosphate. Matrix mineralization in these cultures was assessed by Alizarin Red staining and increased 45Ca uptake. Under these conditions mineralized nodule formation was observed in less than 2 weeks. Northern analysis of TF274 cells at various times during the mineralization process indicated a temporal expression of the osteocalcin gene that is typically associated with differentiating osteoblasts. The osteogenic nature of TF274 cells was confirmed in vivo using the severe combined immunodeficient (SCID) mouse model. Antibodies to human leukocyte antigens (HLA), class I antigens, and human OKa blood group antigen were used to demonstrate that the lesions formed were of human origin. By 21 days, the lesion consisted of a homogeneous focus of ALP-positive cells containing areas of mineralized bone lined with tartarate-resistant acid phosphatase (TRAP) positive osteoclasts. Thus, the TF274 cells exhibit osteogenic potential both in vitro and in vivo. This immortalized cell line represents a consistent source of cells that can be used to study human osteoblast differentiation both in vitro and in vivo.