Biomarker analysis of the ASPEN study comparing zanubrutinib with ibrutinib for patients with Waldenström macroglobulinemia

ABSTRACT

The phase 3 ASPEN trial (NCT03053440) compared Bruton tyrosine kinase inhibitors (BTKis), zanubrutinib and ibrutinib, in patients with Waldenström macroglobulinemia (WM). Post-hoc biomarker analysis was performed using next-generation sequencing on pretreatment bone marrow samples from 98 patients treated with zanubrutinib and 92 patients treated with ibrutinib with mutated (MUT) MYD88 and 20 patients with wild-type (WT) MYD88 treated with zanubrutinib. Of 329 mutations in 52 genes, mutations in CXCR4 (25.7%), TP53 (24.8%), ARID1A (15.7%), and TERT (9.0%) were most common. TP53MUT, ARID1AMUT, and TERTMUT were associated with higher rates of CXCR4MUT (P < .05). Patients with CXCR4MUT (frameshift or nonsense [NS] mutations) had lower very good partial response (VGPR) and complete response rates (CR; 17.0% vs 37.2%, P = .020) and longer time to response (11.1 vs 8.4 months) than patients with CXCR4WT treated with BTKis. CXCR4NS was associated with inferior progression-free survival (PFS; hazard ratio [HR], 3.39; P = .017) in patients treated with ibrutinib but not in those treated with zanubrutinib (HR, 0.67; P = .598), but VGPR + CR rates were similar between treatment groups (14.3% vs 15.4%). Compared with ibrutinib, patients with CXCR4NS treated with zanubrutinib had a favorable major response rate (MRR; 85.7% vs 53.8%; P = .09) and PFS (HR, 0.30; P = .093). In patients with TP53MUT, significantly lower MRRs were observed for patients treated with ibrutinib (63.6% vs 85.7%; P = .04) but not for those treated with zanubrutinib (80.8% vs 81.9%; P = .978). In TP53MUT, compared with ibrutinib, patients treated with zanubrutinib had higher VGPR and CR (34.6% vs 13.6%; P < .05), numerically improved MRR (80.8% vs 63.6%; P = .11), and longer PFS (not reached vs 44.2 months; HR, 0.66; P = .37). Collectively, patients with WM with CXCR4MUT or TP53MUT had worse prognosis compared with patients with WT alleles, and zanubrutinib led to better clinical outcomes.

Zanubrutinib Versus Ibrutinib in Symptomatic Waldenström Macroglobulinemia: Final Analysis From the Randomized Phase III ASPEN Study

The phase III ASPEN study demonstrated the comparable efficacy and improved safety of zanubrutinib versus ibrutinib in patients with Waldenström macroglobulinemia (WM). Here, we report long-term follow-up outcomes from ASPEN. The primary end point was the sum of very good partial response (VGPR) + complete response (CR) rates; secondary and exploratory end points were also reported. Cohort 1 comprised 201 patients (myeloid differentiation primary response 88-mutant WM: 102 receiving zanubrutinib; 99 receiving ibrutinib); cohort 2 comprised 28 patients (myeloid differentiation primary response 88 wild-type WM: 28 zanubrutinib; 26 efficacy evaluable). At 44.4-month median follow-up, VGPR + CR rates were 36.3% with zanubrutinib versus 25.3% with ibrutinib in cohort 1 and 30.8% with one CR in cohort 2. In patients with CXC motif chemokine receptor 4 mutation, VGPR + CR rates were 21.2% with zanubrutinib versus 10.0% with ibrutinib (cohort 1). Median progression-free survival and overall survival were not reached. Any-grade adverse events (AEs) of diarrhea (34.7% v 22.8%), muscle spasms (28.6% v 11.9%), hypertension (25.5% v 14.9%), atrial fibrillation/flutter (23.5% v 7.9%), and pneumonia (18.4% v 5.0%) were more common with ibrutinib versus zanubrutinib; neutropenia (20.4% v 34.7%) was less common with ibrutinib versus zanubrutinib (cohort 1). Zanubrutinib was associated with lower risk of AE-related treatment discontinuation. Overall, these findings confirm the long-term response quality and tolerability associated with zanubrutinib.

Outcomes in grade 3B follicular lymphoma: an international study led by the Australasian Lymphoma Alliance

Grade (G) 3B follicular lymphoma (FL) is a rare FL subtype which exists on a histological continuum between 'lowgrade' (Grade 1, 2 and 3A FL) and diffuse large B-cell lymphoma (DLBCL) appearing to share features with each. Clinical characteristics and outcomes are poorly understood due to lack of adequate representation in prospective trials and large-scale analyses. We analyzed 157 G3BFL cases from 18 international centers, and two comparator groups; G3AFL (n=302) and DLBCL (n=548). Composite histology with DLBCL or low-grade FL occurred in approximately half of the G3BFL cases. With a median of 5 years follow-up, the overall survival and progression-free survival of G3BFL patients was better than that of DLBCL patients (P<0.001 and P<0.001, respectively); however, G3BFL patients were younger (P<0.001) with better performance status (P<0.001), less extranodal disease (P<0.001) and more frequently had normal lactate dehydrogenase (P<0.001) at baseline. The overall and progression-free survival of patients with G3BFL and G3AFL were similar (P=0.83 and P=0.80, respectively). After frontline immunochemotherapy, 24% of G3BFL relapsed; relapse rates were 63% in the DLBCL cohort and 19% in the low-grade FL cohort. Eight percent of relapses occurred beyond 5 years. In this G3BFL cohort, the revised International Prognostic Index successfully delineated risk groups, but the Follicular Lymphoma International Prognostic Index did not. We conclude that patients with immunochemotherapy-treated G3BFL have similar survival outcomes to those with G3AFL, yet a favorable baseline profile and distinctly superior prognosis compared to patients with DLBCL.

ASPEN: Long-term follow-up results of a phase 3 randomized trial of zanubrutinib (ZANU) versus ibrutinib (IBR) in patients with Waldenström macroglobulinemia (WM)

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Background: ASPEN is a randomized, open-label, phase 3 study comparing ZANU, a potent and selective Bruton tyrosine kinase inhibitor (BTKi), with the first-generation BTKi IBR in patients with WM. We present data with a median follow-up of 43 months. Methods: Patients with MYD88 mutations were assigned to cohort 1 and randomized 1:1 to receive ZANU 160 mg twice daily or IBR 420 mg once daily. Randomization was stratified by CXCR4 mutational status and lines of prior therapy (0 vs 1-3 vs > 3). Patients without MYD88 mutations were assigned to cohort 2 and received ZANU 160 mg twice daily. The primary endpoint was proportion of patients achieving complete response or very good partial response (CR+VGPR). Results: A total of 201 patients (ZANU arm, n = 102; IBR arm, n = 99) were enrolled in cohort 1 and 28 patients were enrolled in cohort 2. A larger proportion of patients in the ZANU arm of cohort 1 vs IBR had CXCR4 mutations by next-generation sequencing (32% vs 20%, or 33 of 98 vs 20 of 92 with data available) and were aged > 75 years (33% vs 22%). Median duration of treatment was 42 months (ZANU) and 41 months (IBR), with 67% and 58% remaining on treatment, respectively. The CR+VGPR rate by investigator was 36% with ZANU vs 22% with IBR ( p= 0.02) in cohort 1, and 31% in cohort 2. One patient achieved CR (cohort 2). In patients with wild type or mutant CXCR4 from cohort 1, CR+VGPR rates with ZANU vs IBR were 45% vs 28% ( p= 0.04) and 21% vs 5% ( p= 0.15) , respectively. Median progression-free survival and overall survival were not yet reached. Rates of atrial fibrillation, diarrhea, hypertension, localized infection, hemorrhage, muscle spasms, pneumonia, and adverse events leading to discontinuation or death were lower with ZANU vs IBR (Table). Exposure-adjusted incidence rates of atrial fibrillation/flutter and hypertension were lower with ZANU vs IBR (0.2 vs 0.8 and 0.5 vs 1.0 persons per 100 person-months, respectively; p< 0.05). Rate of neutropenia was higher and rate of grade ≥3 infection was lower with ZANU vs IBR. Safety outcomes of ZANU were similar between cohorts 1 and 2. Conclusions: ASPEN is the largest phase 3 trial with head-to-head BTKi comparison in WM. At a median follow-up of 43 months, ZANU was associated with higher CR+VGPR rate and demonstrated clinically meaningful advantages in long-term safety and tolerability vs IBR. Clinical trial information: NCT03053440. [Table: see text]

Diffuse large B-cell lymphoma: A consensus practice statement from the Australasian Lymphoma Alliance

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype, accounting for 30-40% of lymphoma diagnoses. Though aggressive, cure is achievable in approximately 60% of cases with primary chemo-immunotherapy, and in a further substantial minority by salvage therapy and autologous stem cell transplantation. Despite promising activity in early phase clinical trials, no intensified or novel treatment regimen has improved outcomes over R-CHOP21 in randomised studies. However, there remain several areas of controversy including the most appropriate prognostic markers, CNS prophylaxis and the optimal treatment for patients with high-risk disease. This position statement presents an evidence-based synthesis of the literature for application in Australasian practice. This article is protected by copyright. All rights reserved.

Assessment and management of newly diagnosed classical Hodgkin lymphoma: a consensus practice statement from the Australasian Lymphoma Alliance

The management of Hodgkin lymphoma (HL) has undergone significant changes in recent years. Due to the predilection of HL to affect younger patients, balancing cure and treatment-related morbidity is a constant source of concern for physicians and patients alike. Positron emission tomography adapted therapy has been developed for both early and advanced stage HL to try and improve the outcome of treatment, while minimising toxicities. The aim of this review is to digest the plethora of studies recently conducted and provide some clear, evidence-based practice statements to simplify the management of HL.

Phase 2 study of parsaclisib (INCB050465), a highly selective, next-generation PI3Kδ inhibitor, in relapsed or refractory diffuse large B-cell lymphoma (CITADEL-202)

Parsaclisib, a potent, highly selective, next-generation PI3Kδ inhibitor, was evaluated as monotherapy in CITADEL-202 (NCT02998476), an open-label, multicenter, phase 2 study in patients with relapsed or refractory diffuse large B-cell lymphoma. Patients enrolled into 2 groups (A, Bruton tyrosine kinase [BTK] inhibitor naïve, n = 55; B, BTK inhibitor experienced, n = 5) received oral parsaclisib 20 mg once daily for 8 weeks, then 20 mg once weekly while deriving benefit. The futility boundary was crossed at the interim analysis of Group A, resulting in a negative study. Parsaclisib monotherapy demonstrated an objective response rate (ORR) of 25.5% (8 complete metabolic responses/6 partial metabolic responses) and a median duration of response of 6.2 months. ORR in Group B was 20.0% (1 complete metabolic response). Parsaclisib monotherapy demonstrated manageable toxicities with no new safety signals reported. Further evaluation of parsaclisib in combination with standard therapies and active investigational agents is underway.

ASPEN: Results of a phase III randomized trial of zanubrutinib versus ibrutinib for patients with Waldenström macroglobulinemia (WM)

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Background: Bruton tyrosine kinase (BTK) inhibition is an emerging standard of care for WM. ASPEN is a randomized phase 3 study comparing zanubrutinib (ZANU), a potent and selective BTK inhibitor, versus ibrutinib (IBR), a first generation BTK inhibitor, in WM patients. Methods: Patients with WM and MYD88 mutation were randomly assigned 1:1 to receive ZANU (160 mg twice daily) or IBR (420 mg once daily). Patients without MYD88 mutations were assigned to a separate cohort, received ZANU, and are reported separately. Randomization was stratified by CXCR4 mutational status and the number of lines of prior therapy (0 vs 1-3 vs >3). The primary end point was the proportion of patients achieving a complete response or very good partial response (CR+VGPR). Sample size was calculated to provide 81% power to detect a difference in CR+VGPR rate of 35% vs 15% in the subset of patients with relapsed or refractory (R/R) WM. Primary analysis was planned to occur at ~12 months after last patient enrolled. Results: In total, 201 patients were randomized from Jan 2017 to Jul 2018. The treatment groups were well balanced for important baseline factors, except in the ZANU arm there were more elderly patients (aged >75 years, 33.3% vs 22.2%) and more anemia (hemoglobin ≤110 g/L, 65.7% vs 53.5%). At a median follow-up of 19.4 months, the rate of CR+VGPR was 28.4% vs 19.2% with ZANU vs IBR, respectively (2-sided P=0.09). Rates of atrial fibrillation, contusion, diarrhea, edema peripheral, hemorrhage, muscle spasms, pneumonia, and adverse events (AEs) leading to discontinuation or death were lower with ZANU. The rate of neutropenia was higher with ZANU (Table); however, grade ≥ 3 infection rates were similar (17.8% vs 19.4%). Conclusions: ASPEN is the largest phase 3 trial of BTK inhibitors in WM and the first head-to-head comparison of BTK inhibitors in any disease. Although not statistically significant, ZANU was associated with a higher CR+VGPR response rate, and demonstrated clinically meaningful advantages in safety and tolerability compared to IBR. Clinical trial information: NCT03053440 . [Table: see text]

Updated results of the ASPEN trial from a cohort of patients with MYD88 wild-type (MYD88WT) Waldenström macroglobulinemia (WM)

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Background: Inhibitors of Bruton tyrosine kinase (BTK) have shown significant activity in patients with WM harboring a mutation in the MYD88 gene. However, lower response rates and shorter progression-free survival have been reported in patients with WM who lack such mutations ( N Engl J Med. 2015;372:1430). The ASPEN trial evaluated zanubrutinib (ZANU), a potent and selective BTK inhibitor, in WM patients. Methods: In the ASPEN trial, bone marrow MYD88 mutations were assessed at study entry by a central laboratory (NeoGenomics). Based on the results of the MYD88 mutation assay, patients were assigned to cohort 1 ( MYD88 mutation) or cohort 2 ( MYD88WT or mutation unknown). All cohort 2 patients received ZANU 160 mg twice daily until disease progression. The objective was to assess the safety and efficacy of ZANU in patients with MYD88WT WM. Results: In total, 28 patients with 26 MYD88WT WM were enrolled into cohort 2. The median age was 72 years; 5 patients were treatment-naïve (TN) and 23 patients were relapsed/refractory (R/R; ≥1 prior therapy). Most patients had intermediate- (39.3%) or high-risk (42.9%) disease by International Prognostic Scoring System for WM. With the median follow-up of 17.9 months, 2 patients discontinued ZANU due to adverse events, and 6 patients experienced disease progression; there were no cases of disease transformation. The overall response rate was 80.8%, with a major response rate of 50.0%, including a very good partial response (VGPR) rate of 26.9% (Table). Progression-free survival event-free rate at 12 months was 72.4%. The most frequently reported adverse events (AEs) were diarrhea, anemia, contusion, pyrexia, and upper respiratory tract infection. Major hemorrhage was reported in 2 patients, and atrial fibrillation was reported in 1 patient. There were no fatal AEs. Conclusions: ZANU showed clinically meaningful antitumor activity, including achieving major responses and durability of responses, and was considered well-tolerated with a low discontinuation rate due to AEs, in patients with MYD88WT WM. ZANU demonstrated efficacy regardless of MYD88 mutational status in WM. Clinical trial information: NCT03053440 . [Table: see text]

Australian and New Zealand consensus statement on the management of lymphoma, chronic lymphocytic leukaemia and myeloma during the COVID-19 pandemic

The COVID-19 pandemic poses a unique challenge to the care of patients with haematological malignancies. Viral pneumonia is known to cause disproportionately severe disease in patients with cancer, and patients with lymphoma, myeloma and chronic lymphocytic leukaemia are likely to be at particular risk of severe disease related to COVID-19. This statement has been developed by consensus among authors from Australia and New Zealand. We aim to provide supportive guidance to clinicians making individual patient decisions during the COVID-19 pandemic, in particular during periods that access to healthcare resources may be limited. General recommendations include those to minimise patient exposure to COVID-19, including the use of telehealth, avoidance of non-essential visits and minimisation of time spent by patients in infusion suites and other clinical areas. This statement also provides recommendations where appropriate in assessing indications for therapy, reducing therapy-associated immunosuppression and reducing healthcare utilisation in patients with specific haematological malignancies during the COVID-19 pandemic. Specific decisions regarding therapy of haematological malignancies will need to be individualised, based on disease risk, risks of immunosuppression, rates of community transmission of COVID-19 and available local healthcare resources.

A multicenter retrospective comparison of induction chemoimmunotherapy regimens on outcomes in transplant-eligible patients with previously untreated mantle cell lymphoma

Mantle cell lymphoma (MCL) is an uncommon and typically aggressive form of lymphoma. Although often initially chemosensitive, relapse is common. Several induction and conditioning regimens are used in transplant-eligible patients, and the optimal approach remains unknown. We performed an international, retrospective study of transplant-eligible patients to assess impact of induction chemoimmunotherapy and conditioning regimens on clinical outcomes. We identified 228 patients meeting inclusion criteria. Baseline characteristics were similar among the induction groups except for some variation in age. The type of induction chemoimmunotherapy received did not influence overall response rates (ORRs) (0.43), progression-free survival (PFS) (P > .67), or overall survival (OS) (P > .35) on multivariate analysis (PFS and OS). Delivery of autologous stem cell transplant (ASCT) was associated with favorable PFS and OS (0.01) on univariate analysis only; this benefit was not seen on multivariate analysis-PFS (0.36) and OS (0.21). Compared with busulfan and melphalan (BuMel), the use of the carmustine, etoposide, cytarabine, melphalan (BEAM)-conditioning regimen was associated with inferior PFS (HR = 2.0 [95% CI 1.1-3.6], 0.02) but not OS (HR = 1.1 [95% CI 0.5-2.3], 0.81) on univariate analysis only. Within the limits of a retrospective study and modest power for some comparisons, type of induction therapy did not influence ORR, PFS, or OS for transplant-eligible patients with MCL. International efforts are required to perform randomized clinical trials evaluating chemoimmunotherapy induction regimens.

Phase 2 study of parsaclisib (INCB050465) for relapsed or refractory diffuse large b-cell lymphoma (DLBCL) (CITADEL-202)

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Background: Parsaclisib, a potent, highly selective, next-generation PI3Kδ inhibitor, showed preliminary efficacy as monotherapy for relapsed or refractory non-Hodgkin lymphoma, including DLBCL (Abstract 410, ASH 2017), in a phase 1/2 study. This phase 2 study further assessed parsaclisib in patients (pts) with relapsed or refractory DLBCL (NCT02998476). Methods: Pts enrolled into 2 groups (A, Bruton tyrosine kinase [BTK] inhibitor naïve; B, BTK inhibitor experienced) and received oral parsaclisib 20 mg QD for 8 wks, then 20 mg QW. In a planned interim futility analysis conducted in the first 40 pts treated in Group A, if ≤13 (≤32.5%) responded by IRC assessment, Group A was to be terminated. Results: At data cutoff (22 Jun 2018), 60 pts (Group A, n = 55; Group B, n = 5) were treated (median age, 71 y [range, 36—94]; men, 63.3%; ≥3 prior systemic therapies, 60%). At the planned interim analysis in Group A, ORR (by PET) was 25% (10/40 pts; 5 CMR, 5 PMR); the futility boundary was crossed. At data cutoff, ORR in Group A was 25.5% (14/55 pts; 8 CMR, 6 PMR); median PFS was 2.2 mo (95% CI: 2.0‒4.1); median DOR was 4.5 mo (95% CI: 2.1‒5.1). ORs were observed in germinal center B-cell (GCB) and non-GCB subtypes. ORR in Group B was 20% (1/5 pts; 1 CMR). The most common non-hematologic treatment-emergent adverse events (TEAEs) occurring in > 10% of all pts (all grade [Gr]; Gr 3/4) were rash events (21.7%; 1.7%), colitis/diarrhea events (16.7%; 5%), nausea (16.7%; 0%), cough (15%; 0%), and pyrexia (15%; 8.3%). Gr 3/4 AST and ALT elevations occurred in 5% and 1.7% of pts, respectively; Gr 3/4 neutropenia and anemia occurred in 5% of pts each. The most frequent ( > 5%) serious TEAEs were pyrexia (8.3%), general physical health deterioration (6.7%), and hypercalcemia (6.7%). TEAEs led to therapy discontinuation in 7 pts (2 treatment-related), dose interruption in 20 pts (10 treatment-related), and dose reduction in 3 pts (all treatment-related). Median duration of therapy was 57.5 d (range, 11–318). Conclusions: Parsaclisib monotherapy using a QD followed by QW dosing regimen was well tolerated with no new safety signals reported. Further evaluation of parsaclisib in all subtypes of DLBCL is ongoing in a combination study Clinical trial information: NCT02998476.

Comparison of 2 Doses for ACTH Stimulation Testing in Dogs Suspected of or Treated for Hyperadrenocorticism

BACKGROUND

Lowering the cosyntropin dose needed for ACTH stimulation would make the test more economical.

OBJECTIVES

To compare the cortisol response to 1 and 5 μg/kg cosyntropin IV in dogs being screened for hyperadrenocorticism (HAC) and in dogs receiving trilostane or mitotane for pituitary-dependent HAC.

ANIMALS

Healthy dogs (n = 10); client-owned dogs suspected of having HAC (n = 39) or being treated for pituitary-dependent HAC with mitotane (n = 12) or trilostane (n = 15).

PROCEDURES

In this prospective study, healthy dogs had consecutive ACTH stimulation tests to ensure 2 tests could be performed in sequence. For the first test, cosyntropin (1 μg/kg IV) was administered; the second test was initiated 4 hours after the start of the first (5 μg/kg cosyntropin IV). Dogs suspected of having HAC or being treated with mitotane were tested as the healthy dogs. Dogs receiving trilostane treatment were tested on consecutive days at the same time post pill using the low dose on day 1.

RESULTS

In dogs being treated with mitotane or trilostane, the 2 doses were pharmacodynamically equivalent (90% confidence interval, 85.1-108.2%; P = 0.014). However, in dogs suspected of having HAC, the doses were not pharmacodynamically equivalent (90% confidence interval, 73.2-92.8%; P = 0.37); furthermore, in 23% of the dogs, clinical interpretation of test results was different between the doses.

CONCLUSIONS AND CLINICAL RELEVANCE

For dogs suspected of having HAC, 5 μg/kg cosyntropin IV is still recommended for ACTH stimulation testing. For dogs receiving mitotane or trilostane treatment, a dose of 1 μg/kg cosyntropin IV can be used.

Strong and superplastic nanoglass

The strength-ductility tradeoff has been a common long-standing dilemma in materials science. For example, superplasticity with a tradeoff in strength has been reported for Cu50Zr50 nanoglass (NG) with grain sizes below 5 nm. Here we report an improvement in strength without sacrificing superplasticity in Cu50Zr50 NG by using a bimodal grain size distribution. Our results reveal that large grains impart high strength, which is in striking contrast to the physical origin of the improvement in strength reported in the traditional nanostructured metals/alloys. Furthermore, the mechanical properties of NG with a bimodal nanostructure depend critically upon the fraction of large grains. By increasing the fraction of the large grains, a transition from superplastic flow to failure by shear banding is clearly observed. We expect that these results will be useful in the development of a novel strong and superplastic NG.

Compact test apparatus for evaluation of flow erosion of marine coatings

An apparatus designed and manufactured for evaluation of flow erosion of coatings or layers is presented in this paper. The setup was primarily designed for coatings intended to perform in dynamic marine environments but can be also used for evaluation using fresh water. The concept is based on an in-line flow test cell and modular design allowing good flexibility of varying testing parameters. The flow rate that can be achieved depends on the flow cell geometry and can reach 28 km/h (15 kn) with the presented setup. Temperature may be adjusted between 15 and 35 °C. Particle and metal ion filters are parts of this setup. The dimensions of the apparatus including all components do not exceed 2 m × 2 m × 2 m. The use of the apparatus is illustrated with the results of evaluation of self-polishing anti-fouling coatings and model, silicon wafer grafted layers.

Evaluation of thyroid-stimulating hormone, total thyroxine, and free thyroxine concentrations in hyperthyroid cats receiving methimazole treatment

Background

Iatrogenic hypothyroidism (IH) after treatment of hyperthyroidism can impair renal function. No study compared the efficacy of measurement of serum free thyroxine by equilibrium dialysis (fT4ed) or thyroid‐stimulating hormone (TSH) concentrations for monitoring cats receiving methimazole.

Objectives

To (1) compare the ability of total T4 and fT4ed concentrations in conjunction with TSH to define thyroid function in hyperthyroid cats receiving methimazole, (2) determine the prevalence of IH in cats receiving methimazole, and (3) examine the relationship between thyroid axis hormones and serum creatinine concentration.

Animals

One hundred and twenty‐five serum samples from hyperthyroid cats receiving methimazole and total T4 concentrations ≤3.9 μg/dL.

Methods

Total T4, fT4ed, and TSH concentrations were measured to evaluate thyroid status and serum creatinine concentration was measured to assess renal function. A low total T4 or fT4ed concentration in combination with an increased TSH concentration defined IH.

Results

Forty‐one cats (33%) had increased TSH concentrations. Of cats with total T4 and fT4ed concentrations below the reference range, 68% and 73%, respectively, had TSH concentrations above the reference range. Only 18% of cats with a normal TSH concentration had an increased serum creatinine concentrations as compared to 39% of those with increased TSH concentrations (P < .001).

Conclusions

Free T4ed does not identify more cats with potential IH as compared to total T4. The IH prevalence was approximately 20%. Measurement of TSH may be more helpful in indicating that azotemia, if present, is at least in part related to IH. Investigation is needed to define TSH assay utility in identifying possible subclinical IH.

Effect of trilostane and mitotane on aldosterone secretory reserve in dogs with pituitary-dependent hyperadrenocorticism

Background

Maximal aldosterone secretion in healthy dogs occurs 30 minutes postadrenocorticotropin (ACTH; 5 μg/kg IV) stimulation. The effect of trilostane and mitotane on aldosterone at that time is unknown.

Objectives

To assess the effect of trilostane and mitotane in dogs with pituitary‐dependent hyperadrenocorticism on aldosterone secretory reserve. To determine if aldosterone concentration correlates with electrolyte concentrations.

Animals

Serum collected from 79 client‐owned dogs and 33 stored samples.

Methods

Client‐owned dogs had ACTH stimulation tests with cortisol concentrations measured at 0 and 60 minutes and aldosterone concentrations measured at 0, 30, and 60 minutes. Stored samples had aldosterone concentrations measured at 0 and 60 minutes. Ten historical clinically healthy controls were included. All had basal sodium and potassium concentrations measured.

Results

The aldosterone concentrations in the mitotane‐ and trilostane‐treated dogs at 30 and 60 minutes post‐ACTH were significantly lower than in clinically healthy dogs; no significant difference was detected in aldosterone concentration between 30 and 60 minutes in treated dogs. However, a significantly higher percentage of dogs had decreased aldosterone secretory reserve detected at 30 minutes than at 60 minutes. At 30 minutes, decreased secretory reserve was detected in 49% and 78% of trilostane‐ and mitotane‐treated dogs, respectively. No correlation was detected between aldosterone and serum electrolyte concentrations.

Conclusions and Clinical Importance

Decreased aldosterone secretory reserve is common in trilostane‐ and mitotane‐treated dogs; it cannot be predicted by measurement of serum electrolyte concentrations. Aldosterone concentration at 30 minutes post‐ACTH stimulation identifies more dogs with decreased aldosterone secretory reserve than conventional testing at 60 minutes.

4-O-methylhonokiol, a PPARγ agonist, inhibits prostate tumour growth: p21-mediated suppression of NF-κB activity

BACKGROUND AND PURPOSE

The effects of 4-O-methylhonokiol (MH), a constituent of Magnolia officinalis, were investigated on human prostate cancer cells and its mechanism of action elucidated.

EXPERIMENTAL APPROACH

The anti-cancer effects of MH were examined in prostate cancer and normal cells. The effects were validated in vivo using a mouse xenograft model.

KEY RESULTS

MH increased the expression of PPARγ in prostate PC-3 and LNCap cells. The pull-down assay and molecular docking study indicated that MH directly binds to PPARγ. MH also increased transcriptional activity of PPARγ but decreased NF-κB activity. MH inhibited the growth of human prostate cancer cells, an effect attenuated by the PPARγ antagonist GW9662. MH induced apoptotic cell death and this was related to G(0) -G(1) phase cell cycle arrest. MH increased the expression of the cell cycle regulator p21, and apoptotic proteins, whereas it decreased phosphorylation of Rb and anti-apoptotic proteins. Transfection of PC3 cells with p21 siRNA or a p21 mutant plasmid on the cyclin D1/ cycline-dependent kinase 4 binding site abolished the effects of MH on cell growth, cell viability and related protein expression. In the animal studies, MH inhibited tumour growth, NF-κB activity and expression of anti-apoptotic proteins, whereas it increased the transcriptional activity and expression of PPARγ, and the expression of apoptotic proteins and p21 in tumour tissues.

CONCLUSIONS AND IMPLICATION

MH inhibits growth of human prostate cancer cells through activation of PPARγ, suppression of NF-κB and arrest of the cell cycle. Thus, MH might be a useful tool for treatment of prostate cancer.

Optofluidic variable-focus lenses for light manipulation

This paper presents a planar optofluidic lens for light manipulation utilizing a combination of optofluidic biconvex lens with micromixer. Three light manipulation techniques including tunable optical diverging, collimating and focusing are realized by altering the refractive index of the optofluidic variable-focus lenses formed by solid polydimethylsiloxane (PDMS) walls and tunable liquid lens body. The optical power from the laser input can be increased or decreased with the tuning of the variable-focus lenses' refractive indexes. The optical power adjustment capabilities are demonstrated and characterized. The combinations of benefits of all lens' optical manipulation capabilities, greater mechanical stability, significant increase of optofluidic device's life time and seamless integration with other lab-on-a-chip functionalities provide a promising and versatile optofluidic compartment to integrate with lab-on-a-chip excitation and sensing applications. Optofluidic lens-including system for tunable fluorescence sensing is demonstrated showing 186% increase in detected fluorescence intensity.

Singapore cancer trends in the last decade

In this review, we examine the trends in cancer incidence, mortality and survival in the last decade, using published data from the Singapore Cancer Registry in the period 1998 to 2009. While overall cancer incidences have remained stable, overall cancer mortality rates have declined for both genders. Thus, it is not surprising that there was an improvement in cancer survival. A steady decrease in lung cancer among males and females was observed, thereby leading to a drop in its cancer ranking. In the last five years, the most frequently occurring cancer was colorectal cancer among the male population and breast cancer among females. Survival for both cancers remained relatively optimistic. There is good reason to pay special attention to colorectal cancer due to its high frequency of occurrence among the Singapore population and because it is amenable to early detection via screening.

Aerodynamic effects of inferior turbinate surgery on nasal airflow--a computational fluid dynamics model

BACKGROUND

Turbinate reduction surgery may be indicated for inferior turbinate enlargement when conservative treatment fails. The aim of this study was to evaluate the effects of inferior turbinate surgery on nasal aerodynamics using computational fluid dynamics (CFD) simulations.

METHODS

CFD simulations were performed for the normal nose, enlarged inferior turbinate and following three surgical procedures: (1) resection of the lower third free edge of the inferior turbinate, (2) excision of the head of the inferior turbinate and (3) radical inferior turbinate resection. The models were constructed from MRI scans of a healthy human subject and a turbulent flow model was used for the numerical simulation. The consequences of the three turbinate surgeries were compared with originally healthy nasal model as well as the one with severe nasal obstruction.

RESULTS

In the normal nose, the bulk of streamlines traversed the common meatus adjacent to the inferior and middle turbinate in a relatively vortex free flow. When the inferior turbinate was enlarged, the streamlines were directed superiorly at higher velocity and increased wall shear stress in the nasopharynx. Of the three surgical techniques simulated, wall shear stress and intranasal pressures achieved near-normal levels after resection of the lower third. In addition, airflow streamlines and turbulence improved although it did not return to normal conditions. As expected, radical turbinate resection resulted in intra-nasal aerodynamics of atrophic rhinitis demonstrated in previous CFD studies.

CONCLUSION

There is little evidence that inspired air is appropriately conditioned following radical turbinate surgery. Partial reduction of the hypertropic turbinate results in improved nasal aerodynamics, which was most evident following resection of the lower third. The results were based on a single individual and cannot be generalised without similar studies in other subjects.

A review of the implications of computational fluid dynamic studies on nasal airflow and physiology

BACKGROUND

Computational fluid dynamics has been adapted to studying nasal aerodynamics.

AIM

To review current literature on CFD studies, with an emphasis on normal nasal airflow, the impact of sinonasal pathology on airflow, and implications on nasal physiology. The objective is to provide the rhinologists with a greater understanding of nasal airflow and how symptomatology of sinonasal disease may be explained via CFD simulations.

RESULTS

The nasal valve region redirects inspiratory airstreams over the inferior turbinate in a high turbulent kinetic energy, which is important in heat and moisture exchange. The bulk of airflow occurs in the common meatus with small streams traversing the olfactory groove, increasing during sniffing. Septal deviation and enlarged inferior turbinate causes redistribution of airflow, changes in intranasal pressure and increased turbulence. High velocity airflow and wall shear stress at the septal perforation causes desiccation and mucosal damage. The airflow within an atrophic nasal cavity is predominantly laminar with minimal contact with nasal mucosa. The inferior turbinate is an important organ for air conditioning and preservation during surgery is highlighted.

CONCLUSIONS

Despite some limitations of CFD simulations, this technology has improved understanding of the complex nasal anatomy and the implications of disease and surgery on physiology.

Ministry of health clinical practice guidelines: cancer screening

The Ministry of Health publishes national clinical practice guidelines to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with key recommendations from the guidelines) from the Ministry of Health clinical practice guidelines on cancer screening, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov. sg/mohcorp/publications.aspx?id=24018). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Community psycho-behavioural surveillance and related impact on outbreak control in Hong Kong and Singapore during the SARS epidemic

1. The promotion of personal protective health practices must take into account background perceptions of risk and psychological responses in the community-at-large. 2. Population psycho-behavioural factors in Hong Kong and Singapore are shown to be an important potential vector for the transmission of an infectious agent. 3. Comparative psycho-behavioural surveillance and analysis can yield important insights into generic versus population-specific issues that could be used to inform, design and benchmark public health infection control measures.

Study of Materials Deformation in Nanometric Cutting by Large-scale Molecular Dynamics Simulations

Nanometric cutting involves materials removal and deformation evolution in the surface at nanometer scale. At this length scale, atomistic simulation is a very useful tool to study the cutting process. In this study, large-scale molecular dynamics (MD) simulations with the model size up to 10 millions atoms have been performed to study three-dimensional nanometric cutting of copper. The EAM potential and Morse potential are used, respectively, to compute the interaction between workpiece atoms and the interactions between workpiece atoms and tool atoms. The material behavior, surface and subsurface deformation, dislocation movement, and cutting forces during the cutting processes are studied. We show that the MD simulation model of nanometric cutting has to be large enough to eliminate the boundary effect. Moreover, the cutting speed and the cutting depth have to be considered in determining a suitable model size for the MD simulations. We have observed that the nanometric cutting process is accompanied with complex material deformation, dislocation formation, and movement. We find that as the cutting depth decreases, the tangential cutting force decreases faster than the normal cutting force. The simulation results reveal that as the cutting depth decreases, the specific cutting force increases, i.e., "size effect" exists in nanometric cutting.

Ovarian cancer incidence and survival in Korea: 1993-2002

This study examined incidence rates, histologic and stage distribution, and long-term survival rates of patients with ovarian cancer in Korea. A total of 11,404 patients diagnosed with ovarian cancer between 1993 and 2002 were reported to the Korea Central Cancer Registry and the Gynecologic Oncology Committee of Korean Society of Obstetrics and Gynecology. All rates were expressed per 100,000. The age-standardized incidence rates were 3.79 and 4.74 per 100,000 women in 1993 and 2002, respectively. The incidence rates of ovary cancer increased with age in Korea, and over half of the patients were in the stage IA (24.8%) and IIIC (26.8%) in this study. The 5-year relative survival rate was 59.6%. Relative survivals according to the stage of FIGO at 5 years were 91.1%, 75.2%, 46.4%, and 21.2% for stages I, II, III, and IV, respectively. The 5-year relative survivals of germ cell tumors and epithelial ovarian cancer were 89.0% and 58.3%, respectively. Surgical stage and histology were the most important prognostic factors of ovarian cancer. However, the 5-year survival rate of FIGO stage IC was significantly higher than that of stage IB.

Thermal–mechanical study of functionally graded dental implants with the finite element method

This article investigates the thermal-mechanical performance of hydroxyapatite/titanium (HA/Ti) functionally graded (FG) dental implants with the three-dimensional finite element method. The stresses induced by occlusal force for the present HA/Ti FG implant are calculated to compare with the corresponding stresses for the titanium dental implant. Thermal-mechanical effect of temperature variation due to daily oral activity is also studied. The HA/Ti FG dental implant performance is evaluated against the maximum von Mises stress, which is the general performance indicator, the first principal/tensile stress for mechanical failure of implant-bone-bond and the third principal/compressive stress for bone absorption. Simulation results indicate that under the influence of occlusal force only, the FG implants with different HA fraction along the implant length perform almost equally well, while the titanium implant sustains much higher von Mises stress. However, when thermal stress is also considered, the FG implant having HA fraction exponential index of m = 2 with temperature decrease of 20 degrees C yields the highest first principal and von Mises stresses among all the FG and titanium implants.

Parallel sequential minimal optimization for the training of support vector machines

Sequential minimal optimization (SMO) is one popular algorithm for training support vector machine (SVM), but it still requires a large amount of computation time for solving large size problems. This paper proposes one parallel implementation of SMO for training SVM. The parallel SMO is developed using message passing interface (MPI). Specifically, the parallel SMO first partitions the entire training data set into smaller subsets and then simultaneously runs multiple CPU processors to deal with each of the partitioned data sets. Experiments show that there is great speedup on the adult data set and the Mixing National Institute of Standard and Technology (MNIST) data set when many processors are used. There are also satisfactory results on the Web data set.

Molecular dynamics simulation of size and strain rate dependent mechanical response of FCC metallic nanowires

Current computational simulations on metallic nanowires are largely focused on ultrathin wires with characteristic sizes smaller than 2 nm. The electronic, thermal and optical properties form the bulk of these studies, with investigations of the mechanical properties centred on the breaking force of monatomic chains, and the structural evolution of small nanowires subjected to axial, shear, bending and torsional forces. This study seeks to build on the wealth of current knowledge for computational simulation on the mechanical properties of metallic nanowires. The simulation scale will be upped to 24 000 atoms to study a larger metallic nanowire with a 6 nm characteristic size scale. The commonly studied Au nanowire is studied in conjunction with the rarely examined Pt nanowire. The effects that size and strain rate have on the stretching behaviour of these nanowires are investigated through the simulation of nanowires with three characteristic sizes of 2, 4 and 6 nm, subjected to three distinct strain rates of 4.0 x 10(8), 4.0 x 10(9) and 4.0 x 10(10) s(-1). The selected strain rates produce three distinct modes of deformation, namely crystalline-ordered deformation, mixed-mode deformation and amorphous-disordered deformation, respectively. The mechanisms behind the observations of these distinct deformation modes are analysed and explained. A Doppler 'red-shift' effect is observed when the nanowires are strained at the highest strain rate of 4.0 x 10(10) s(-1). This effect is most pronounced for the nanowire subjected to the largest stretch velocity. As a result, a constrained dynamic free-vibration phenomenon is observed during stretching, which eventually leads to delocalized multiple necking, instead of a single localized neck when it is strained at a lower rate. This unique phenomenon is discussed and future research effort is in the pipeline for a more detailed investigation into metallic nanowires strained at a supersonic velocity.

Snoring source identification and snoring noise prediction

This paper investigates the snoring mechanism of humans by applying the concept of structural intensity to a three-dimensional (3D) finite element model of a human head, which includes: the upper part of the head, neck, soft palate, hard palate, tongue, nasal cavity and the surrounding walls of the pharynx. Results show that for 20, 40 and 60Hz pressure loads, tissue vibration is mainly in the areas of the soft palate, the tongue and the nasal cavity. For predicting the snoring noise level, a 3D boundary element cavity model of the upper airway in the nasal cavity is generated. The snoring noise level is predicted for a prescribed airflow loading, and its range agrees with published measurements. These models may be further developed to study the various snoring mechanisms for different groups of patients.

Measurement of 224Ra uptake in a fern actively accumulating radium

A method is proposed for determining the level of 224Ra in plant samples by measuring its descendant nuclide 212Pb at 239 keV by gamma-ray spectrometry. Variations of 224Ra and 212Pb over time during sample preparation and counting were delineated prior to gamma-ray measurement. The 224Ra concentrations in plant samples were measured by their direct uptake from soil, which could be determined and distinguished from that resulting from decay of 228Th inside the plants. We propose that a field-growing Dicranopteris linearis, which actively accumulates radium, can be used as an indicator of the nutritional transportation and metabolic rate of radium and other alkaline earth elements. We investigated the influence of rainfall on 224Ra concentrations in fronds of D. linearis and the corresponding uptake rates. 224Ra could serve as a natural tracer of growth in plants over a several days. Its presence and content in plants implies a temporal mineral metabolic rate, which can provide useful information for plant physiological and environmental investigations.

Cupping: From a biomechanical perspective

The effectiveness of the cupping technique, a treatment modality in Traditional Chinese Medicine, in stimulating acupuncture points for pain relief was examined in this paper from a biomechanical perspective. Parametric studies including the effects of vacuum pressure, loading rate, friction coefficient at the cup-skin interface, and size and shape of the cup were carried out using a model based on the finite-element method. The anatomical structures of skin, fat, and muscle were modelled. All the soft-tissue layers were assumed to be nonlinearly elastic and viscoelastic. The rim of the cup was also modelled to study the interaction between cup and skin; the cup rim was assumed to be rigid. The simulation results showed that the stresses in the soft tissue were increased for increasing applied vacuum pressures and that the effects of cupping were mostly limited to the region enclosed by the cup. The simulations also indicated that the magnitude of the applied vacuum may have had direct implications for the severity of bruising of the skin following cupping treatment. Most significantly, the simulation results contradicted the established practice of cup size selection according to the depth of the disorder. Experimental verification of the proposed multi-layered finite-element model is presented. The nature of the bruising inherent to the cupping treatment is also explained by the proposed model.

A three-dimensional human head finite element model and power flow in a human head subject to impact loading

A three-dimensional finite element model of the human head is presented. The model has been validated against two sets of experimental results. To assess injury likelihood of the head subjected to impact loading, the structural intensity (SI) methodology is introduced in accordance with the prevailing practice in experimental biomechanics. SI is a vector quantity indicating the direction and magnitude of power flow inside a dynamically loaded structure. In this paper, the SI field inside the head model is computed for three cases, namely frontal, rear and side impacts. The results for the three cases have revealed that there exist power flow paths. The skull is, in general, a good energy flow channel. The study has also revealed the high possibility of spinal cord injury due to wave motion inside the head.

Assessing clinical performance of gynecology residents: sonographic evaluation of adnexal masses based on morphological scoring systems

OBJECTIVE

To assess the performance of inexperienced gynecology residents in the evaluation of adnexal masses using sonographic scoring systems.

METHODS

From April 2003 to October 2004, transvaginal sonography was performed preoperatively by junior gynecology residents on 1-month shifts on 123 patients suspected of having adnexal masses. A total of 137 adnexal masses were found and evaluated using two different morphological scoring systems (those of DePriest and Lerner). The diagnostic performance of the sonographic scoring systems was assessed using the McNemar test and receiver-operating characteristics (ROC) curve analysis was used for lesion characterization. The diagnostic accuracy when the results of both scoring systems satisfied malignancy cut-off values was also investigated.

RESULTS

Histopathological analysis revealed that, of the 137 lesions, 109 were benign, 23 were malignant and five were borderline. Best clinical cut-off levels were > or = 5 on the DePriest and > or = 3 on the Lerner scores. Both systems achieved good performance for characterizing malignancy. No significant difference was found in terms of the accuracy of the two systems as determined by mean areas under the ROC curves (0.816 and 0.783, P = 0.562). The combined approach using both scoring systems resulted in higher specificity (77.1%, P < 0.05) and positive predictive value without a significant decrease in sensitivity (82.1%) compared with either system alone. Of the 43 histologically confirmed false-positive cases, mature cystic teratoma was most common, with 13/22 (59%) cases being misinterpreted as malignancies.

CONCLUSION

Junior residents, inexperienced at sonography, performed fairly in terms of evaluating adnexal masses with the help of morphological scoring systems.

King Edward VII Hall of Residence--a link with the medical school since 1916

King Edward VII ("KE") had been synonymous with the medical school and its associated hall of residence at Sepoy Lines since the 1910s. After the school became the Medical Faculty, the illustrious name remained with the Hall, which was rebuilt in 1957. For almost 90 years, KE has kept alive the rich history and traditions of a bygone era that embodied the passion and pride of both Singapore and Malaysia. The heroism of some Keviians during the Second World War and other exploits have led to many legends of the Hall. In 1987, it moved to its present location at Kent Ridge, and opened its doors to students from all other faculties. We count many personalities among our alumni, including some of the most prominent physicians in our country. The exuberant hall life, cultural pursuits and achievements of the residents contribute to the strong spirit of endeavour. Keviians over the decades have lived, worked, played and served to uphold the motto that means so much to all of us: TO STRIVE, TO SEEK, TO SERVE.

Teaching community, occupational and family medicine at the National University of Singapore: past, present and future

INTRODUCTION

We describe how the curriculum of community, occupational and family medicine (COFM) has evolved in response to social and educational forces and local health needs. Challenges in the teaching of the curriculum are also discussed.

CURRICULUM

The COFM Department aims to produce medical undergraduates and graduates with the skills to critically appraise evidence, prevent and manage diseases, and promote health in the community and primary healthcare setting. Its teaching programmes consist of the medical undergraduate programme and the Master of Medicine programmes in Occupational Medicine, Public Health and Family Medicine. The undergraduate modules consist of evidence-based medicine, public health in the community, disease prevention and control, occupational medicine practice, health promotion and behaviour, and communication with patients. The university's first completely online module on SARS was jointly implemented by the Department and the Centre for Instructional Technology for the entire student population last year. The COFM curriculum has shifted from giving students factual information through lectures to developing students' critical thinking and problem-solving skills through small group teaching, case studies and community health projects. Innovative assessment methods such as open-book examinations; objective structured communication stations with simulated patients; and evaluation of students' participation in group work are used to assess students' skills in problem-solving, communication and teamwork respectively.

CONCLUSION

While the Department has made significant progress in developing a relevant and updated curriculum based on appropriate learning and assessment approaches, it will strive to do more to develop students' critical thinking skills by using newer approaches.

Epstein-Barr virus plays little role in cervical carcinogenesis in Korean women

We examined whether Epstein-Barr virus (EBV) infection plays a role in cervical carcinogenesis in Korean women. EBV infection was examined using polymerase chain reaction (PCR) with two different primer pairs flanking the BamHI "W" fragment of EBV and by EBV-encoded small RNAs (EBER) in situ hybridization in various histologic types of cervical cancer, including 17 cases of squamous cell carcinoma, 36 cases of adenocarcinoma, and 3 cases of small-cell carcinoma. We also evaluated 20 cases of cervical intraepithelial neoplasia and 20 cases of normal uterine cervix. One case of squamous cell carcinoma and three cases of cervical intraepithelial neoplasia were positive for EBV DNA using PCR, but EBER in situ hybridization analysis showed that none of the PCR-positive cases expressed EBER. EBV DNA was not found using PCR in any of the 20 normal uterine cervices. From our results, EBV infection does not seem to play a role in cervical carcinogenesis in Korean women.

Compensation of polarization-dependent loss in transmission fiber gratings by use of a Sagnac loop interferometer

We analyze the transmission characteristics of a Sagnac loop interferometer containing a polarization-dependent loss element and lossless polarization-converting elements by use of Jones matrices. We show that polarization independence in the transmission mode can be achieved in such a configuration and that maximum transmittance occurs when a half-wave plate is used for the polarization-converting element. The result is verified experimentally for a fiber acousto-optic tunable filter and cascaded long-period fiber gratings with either intrinsic or process-induced polarization-dependent filtering characteristics.

Polymorphism in the E6 gene of human papillomavirus type 16 in the cervical tissues of Korean women

The aim of this study was to identify sequence variants in the HPV 16 E6 gene in Korean women and to examine the possible association between these sequence variants and cervical cancer development. We examined the HPV 16 DNA of 215 patients with no cervical disease (NCD) (n = 105) or with cervical neoplasia (n = 110) [cervical intraepithelial neoplasia (CIN), n = 61; invasive cervical carcinoma (ICC), n = 49] using the nested polymerase chain reaction (PCR) and PCR-directed sequencing methods. Fifty-four (NCD, n = 10; CIN, n = 17; ICC, n = 27) of the 215 samples contained HPV 16 E6 DNA, but only two (7.4%) of 27 ICC samples had prototype sequences. The most frequently found variation was D25E (in NCD, n = 8, 80%; in CIN, n = 9, 52.9%; in ICC, n = 23, 85.2%). This is a rare variation in western countries. No significance difference was found between the frequencies of D25E variation in cancerous and non-cancerous lesions. Among the 11 kinds of variants identified, four variants were novel and have been registered with GenBank. This study demonstrates that the D25 variant is the most prevalent E6 genomic variant type in Korean population. However, it was not found to be associated with an increased risk of ICC.

Model development and numerical simulation of electric-stimulus-responsive hydrogels subject to an externally applied electric field

Based on a multi-phasic mixture theory with consideration of ionic diffusion and convection, a multi-physic model, called the multi-effect-coupling electric-stimulus (MECe) model, is developed for simulation of responsive behavior of the electric-sensitive hydrogels when they are immersed into a bathing solution subject to an externally applied electric field. In the developed model, with chemo-electro-mechanical coupling effects, the convection-diffusion equations for concentration distribution of diffusive ions incorporate the influence of electric potential. The electroneutrality condition is replaced by the Poisson equation for distribution of electric potential. The steady and transient analyses of hydrogel deformation are easily carried out by the continuity and momentum equations of the mixture phase. Further, the computational domain of the present model covers both the hydrogel and the surrounding solution. In order to solve the present mathematical model consisting of multi-field coupled nonlinear partial differential governing equations, a hierarchical iteration technique is proposed and a meshless Hermite-Cloud method (HCM) is employed. The steady-state simulation of the electric-stimulus responsive hydrogel is numerically conducted when it is subjected to an externally applied electric field. The hydrogel deformation and the ionic concentrations as well as electric potentials of both the hydrogel and external solution are investigated. The parameter influences on the swelling behaviors of the hydrogel are also discussed in detail. The simulating results are in good agreement with the experimental data and they validate the presently developed model.

Trends in cancer incidence among Singapore Malays: a low-risk population

INTRODUCTION

Inspection of trends in cancer incidence in ethnically or geographically diverse populations is important for the understanding of cancer patterns and also to provide clues for aetiologic studies. There is little information on cancer incidence among Malays, a low-risk population. The population-based cancer registration system in Singapore offers the opportunity in this regard.

MATERIALS AND METHODS

A review of all newly diagnosed cancer cases among Singapore Malay residents in the period 1968 to 1997 was conducted to determine the time trends using data from Singapore Cancer Registry. Age-standardised incidence rates and average annual percentage change, using Poisson regression, were calculated.

RESULTS

During the 30-year study period, a total of 9101 incident cases of cancer were diagnosed among Malays in Singapore. The 3 most common sites of cancer were lung, liver and colorectum in males; and breast, colorectum and ovary in females in the period 1983 to 1997. Leukaemia was among the top 10 cancer sites in both sexes. Malays generally experienced lower cancer incidence rates compared to Chinese, but rates have been increasing at 1.5% to 2% annually. Statistically significant increases in incidence were observed for most of the cancer sites. The incidence of nasopharyngeal carcinoma increased, while there were no significant changes in the general population.

CONCLUSION

The relatively lower cancer risk among Singapore Malays might be attributed to genetic factors or closer adherence to a more traditional lifestyle. This study provides a baseline for comparisons with other populations with diverse cancer risk patterns in order to obtain a better understanding of possible aetiologic factors.

Coherent acousto-optic mode coupling in dispersion-compensating fiber by two acoustic gratings with orthogonal vibration directions

The acousto-optic mode coupling from core to LP11(cl) mode of a dispersion-compensating fiber excited by two acoustic waves with orthogonal perturbations is studied by use of a novel composite piezoelectric transducer. Highly polarization-dependent mode-selective spectra are observed that are due to coherent acousto-optic coupling between the core and various constituent cladding modes. Potential applications for implementing an all-fiber wavelength-tunable polarization analyzer are also discussed.

Basal cell carcinoma, squamous cell carcinoma and melanoma of the skin: analysis of the Singapore Cancer Registry data 1968-97

BACKGROUND

There has been an alarming recent increase in skin cancer incidence among fair-skinned populations. Information from Asian populations is less readily available.

OBJECTIVES

This study examines time trends and ethnic differences of skin cancers among Asians in Singapore.

METHODS

Data from 1968 to 1997 was obtained from the Singapore Cancer Registry, a population-based registry. Age-standardized incidence rates (ASRs) and age-adjusted average annual percentage change, using the Poisson regression model, were calculated.

RESULTS

A total of 2650 basal cell carcinomas (BCCs), 1407 squamous cell carcinomas (SCCs) and 281 melanomas were reported. There was an overall increase of skin cancer from 6.0 per 100000 person years (1968-72) to 8.9 per 100000 person years (1993-97). BCC incidence increased 3% annually, melanoma remained constant, and SCC decreased 0.9% annually. BCC ASRs were highest among Chinese, then Malays and Indians. A similar pattern was noted for SCC and melanomas.

CONCLUSIONS

The incidence rates of skin cancer increased in Singapore during the period 1968-97. Fairer-skinned Chinese had a higher incidence of skin cancer.

Measurement of modal dispersion in optical fiber by means of acousto-optic coupling

We show that frequency-wavelength tuning characteristics of acousto-optic coupling can be used for measuring the difference of effective index, group index, and chromatic dispersion between core and cladding modes in single-mode fibers. Chromatic dispersion measurements of a 30-cm-long conventional single-mode fiber, a nonzero dispersion-shifted fiber, and a dispersion-compensating fiber with this new method are presented for the wavelength range 1500-1600 nm. Qualitative agreement with independently measured data is obtained.

Constitutive model development and micro-structural topology optimisation for Nafion hydrogel membranes with ionic clustering

The deployment of electroactive ionic polymer hydrogel-metal composites in artificial muscle and BioMEMS applications has recently been intensively investigated. In order to analyse their electromechanical responses to externally applied electrical fields, it is critical to develop a constitutive model linking the macro-mechanical moduli with the micro-mechanical characteristics, and to determine the geometric size and shape of the micro-structural cluster and investigate the effect of cluster morphology on the effective electro-elastic moduli of the polymer hydrogels. As a typical ionic polymer-based hydrogel, the Nafion membrane is studied in this work. Based on the Biot poroelasticity theory, a multi-scale constitutive model which includes both macro and micro characteristics is developed using an asymptotic homogenisation method. The effect of water-volume fraction on the effective elastic moduli of the hydrogel membrane is examined for different equivalent weights. Numerical investigations show that the simulated effective constitutive moduli agree well with experimental data. The presently developed constitutive model is thus validated. In order to determine the micro-structural shape of the polymer skeleton subject to fluid pressure, a representative volume element (RVE) is designed by topology optimisation of the periodic microstructures of the Nafion hydrogels, through the minimisation of the electro-elastic interaction energy between the polymer-based fluorocarbon matrix and the surrounding fluid. This optimal RVE correctly predicts the geometric shapes of the clusters.

Alcohol, tobacco and breast cancer--collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease

Alcohol and tobacco consumption are closely correlated and published results on their association with breast cancer have not always allowed adequately for confounding between these exposures. Over 80% of the relevant information worldwide on alcohol and tobacco consumption and breast cancer were collated, checked and analysed centrally. Analyses included 58,515 women with invasive breast cancer and 95,067 controls from 53 studies. Relative risks of breast cancer were estimated, after stratifying by study, age, parity and, where appropriate, women's age when their first child was born and consumption of alcohol and tobacco. The average consumption of alcohol reported by controls from developed countries was 6.0 g per day, i.e. about half a unit/drink of alcohol per day, and was greater in ever-smokers than never-smokers, (8.4 g per day and 5.0 g per day, respectively). Compared with women who reported drinking no alcohol, the relative risk of breast cancer was 1.32 (1.19-1.45, P<0.00001) for an intake of 35-44 g per day alcohol, and 1.46 (1.33-1.61, P<0.00001) for >/=45 g per day alcohol. The relative risk of breast cancer increased by 7.1% (95% CI 5.5-8.7%; P<0.00001) for each additional 10 g per day intake of alcohol, i.e. for each extra unit or drink of alcohol consumed on a daily basis. This increase was the same in ever-smokers and never-smokers (7.1% per 10 g per day, P<0.00001, in each group). By contrast, the relationship between smoking and breast cancer was substantially confounded by the effect of alcohol. When analyses were restricted to 22 255 women with breast cancer and 40 832 controls who reported drinking no alcohol, smoking was not associated with breast cancer (compared to never-smokers, relative risk for ever-smokers=1.03, 95% CI 0.98-1.07, and for current smokers=0.99, 0.92-1.05). The results for alcohol and for tobacco did not vary substantially across studies, study designs, or according to 15 personal characteristics of the women; nor were the findings materially confounded by any of these factors. If the observed relationship for alcohol is causal, these results suggest that about 4% of the breast cancers in developed countries are attributable to alcohol. In developing countries, where alcohol consumption among controls averaged only 0.4 g per day, alcohol would have a negligible effect on the incidence of breast cancer. In conclusion, smoking has little or no independent effect on the risk of developing breast cancer; the effect of alcohol on breast cancer needs to be interpreted in the context of its beneficial effects, in moderation, on cardiovascular disease and its harmful effects on cirrhosis and cancers of the mouth, larynx, oesophagus and liver.

Cancer incidence in Singapore, 1998 to 1999

The age-standardised incidence rates for all cancers for 1998-1999 were 235.0 per 100,000 in males and 199.8 per 100,000 in females. The corresponding rates for 1993-1997 were 233.1 per 100,000 in males and 198.1 per 100,000 in females. The greatest difference was for breast cancer in females with age-standardised incidence rates increasing from 46.1 to 53.1 cases per 100,000 persons per year between these time periods. There also appears to be a shift of the peak age-specific incidence for breast cancer from premenopausal to postmenopausal years over this period. This suggests that our breast cancer incidence pattern is rapidly becoming more similar to populations in the West.

Singapore Chinese Health Study: development, validation, and calibration of the quantitative food frequency questionnaire

This report describes the development and validation/calibration of a structured food frequency questionnaire for use in a large-scale cohort study of diet and health in Chinese men and women aged 45-74 years in Singapore, the development of a food composition database for analysis of the dietary data, and the results of the dietary validation/calibration study. The present calibration study comparing estimated intakes from 24-hour recalls with those from the food frequency questionnaires revealed correlations of 0.24-0.79 for energy and nutrients among the Singapore Chinese, which are comparable to the correlation coefficients reported in calibration studies of other populations. We also report on the nutritional profiles of Singapore Chinese on the basis of results of 1,880 24-hour dietary recalls conducted on 1,022 (425 men and 597 women) cohort subjects. Comparisons with age-adjusted corresponding values for US whites and blacks show distinct differences in dietary intakes between the Singapore and US populations. The Singapore cohort will be followed prospectively to identify dietary associations with cancer risk and other health outcomes.

Effects of restricted feeding, low-energy diet, and implantation of trenbolone acetate plus estradiol on growth, carcass traits, and circulating concentrations of insulin-like growth factor (IGF)-I and IGF-binding protein-3 in finishing barrows

Effects of restricted feeding (80% ad libitum), feeding a low-energy diet containing 84% DE (2.95 Mcal/kg) of the control diet, and implantation of Revalor H (140 mg trenbolone acetate plus 14 mg estradiol-17beta) on growth, carcass traits, and serum concentrations of insulin-like growth factor (IGF)-I and IGFbinding protein-3 (IGFBP-3) were studied in crossbred finishing barrows beginning from 59 +/- 0.9 kg of body weight. Blood samples were taken every 3 wk and the animals were slaughtered at approximately 105 kg body weight. Restricted feeding caused a decrease (P < 0.01) in ADG; feeding the low-energy diet was effective in reducing backfat thickness but decreased gain:feed; the implantation caused a decrease in ADG, feed intake, and backfat thickness and increased gain:feed. Overall pork quality based on pH, drip loss, and the lightness in color of longissimus muscle was not affected by any of the treatments. Serum IGF-I concentration increased following the implantation but did not change (P > 0.05) due to other treatments. Immunoreactive IGFBP-3 concentration was not changed by any of the treatments. Overall ADG was positively correlated with early-stage (d 21) IGF-I and IGFBP-3 concentrations only in unimplanted barrows, whereas backfat thickness was negatively correlated with d-42 IGF-I concentration in all but unimplanted barrows with ad libitum intake. A strong positive correlation (P < 0.01) between IGF-I and IGFBP-3 concentrations was apparent with increasing age of the animals. Results suggest that growth rate and backfat thickness are decreased by a moderate restriction of feed or energy intake with no accompanying changes in circulating IGF-I and IGFBP-3 concentrations and that the beneficial effect of Revalor H implantation on feed efficiency may be mediated, in part, by IGF-I. Moreover, both IGF-I and IGFBP-3 concentrations may be useful as growth indices in pigs.