1204 Analyzing User Journey Data In Digital Health: Predicting Dropout From A Digital CBT-I Intervention

Introduction

Intervention dropout is an important factor for the evaluation and implementation of digital therapeutics, including in insomnia. Large amounts of individualized data (logins, questionnaires, EMA data) in these interventions can combine to create user journeys - the data generated by the path an individual takes to navigate the digital therapeutic. User journeys can provide insight about how likely users are to drop out of an intervention on an individual level and lead to increased prediction performance. Thus, the goal of this study is to provide a step-by-step guide for the analysis of user journeys and utilize this guide to predict intervention dropout, illustrated with an example from a data in a RCT of digital therapeutic for chronic insomnia, for which outcomes have previously been published.

Methods

Analysis of user journeys includes data transformation, feature engineering, and statistical model analysis, using machine learning techniques. A framework is established to leverage user journeys to predict various behaviors. For this study, the framework was applied to predict dropouts of 151 participants from a fully automated web-based program (SHUTi) that delivered cognitive behavioral therapy for insomnia. For this task, support vector machines, logistic regression with regularization, and boosted decision trees were applied at different points in 9-week intervention. These techniques were evaluated based on their predictive performance.

Results

After model evaluation, a decision tree ensemble achieved AUC values ranging between 0.6-0.9 based on application of machine earning techniques. Various handcrafted and theory-driven features (e.g., time to complete certain intervention steps, time to get out of bed after arising, and days since last system interaction contributed to prediction performance.

Conclusion

Results indicate that utilizing a user journey framework and analysis can predict intervention dropout. Further, handcrafted theory-driven features can increase prediction performance. This prediction of dropout could lead to an enhanced clinical decision-making in digital therapeutics.

Support

The original study evaluating the efficacy of this intervention has been reported elsewhere and was funded by grant R01 MH86758 from the National Institute of Mental Health.

Precision Oncology With Radiogenomics: Non-invasive Interrogation of Liver Cancer Genomics to Select Drug Therapy and Monitor Patient Response

Background: Significant intratumoral heterogeneity is present in hepatocellular carcinoma (HCC) and single biopsy samples severely underread the genomic profile of the tumor. This confounds drug development in HCC and makes it extremely challenging to stratify and prognosticate patients to select therapy on the basis of genomic biomarkers. Multiregion sampling of surgically resected HCC allows for these intratumoral heterogeneity to be unraveled and this is currently carried out in our prospective PLANET (Precision Medicine in Liver Cancer across an Asia-Pacific Network) program. However, multiregion sampling is not practical in unresectable HCC cases, which comprise 80% of the disease burden. Radiogenomics studies on liver, lung and head-and-neck cancers have established the capability of radiomics analysis in capturing intratumor heterogeneity with the identification of radiomics signatures that are representative of underlying gene expression patterns. Aim: On this basis, our PLANET program has adopted a radiogenomics approach to characterize the intratumoral heterogeneity in HCC. Methods: This approach will leverage on the correlation of distinctive imaging traits in CT scans against the gene expression profiles of surgically resected HCC patients. Our PLANET program and the data-science enterprise Holmusk have embarked on close collaborative efforts to develop an algorithm that characterizes intratumoral heterogeneity based on distinctive traits in the CT scans. Results and conclusion: The development of such an algorithm is potentially ground-breaking as it allows for the noninvasive interrogation of liver cancer genomics and prognostication of HCC patients. This allows the easy screening of patients for therapeutic targets in vivo and will significantly improve the selection of drug therapy and monitoring of therapeutic response in HCC.

Pressure dependence of Ce valence in CeRhIn5

We have studied the Ce valence as a function of pressure in CeRhIn₅ at 300 K and at 22 K using x-ray absorption spectroscopy in partial fluorescent yield mode. At room temperature, we found no detectable change in Ce valence greater than 0.01 up to a pressure of 5.5 GPa. At 22 K, the valence remains robust against pressure below 6 GPa, in contrast to the predicted valence crossover at P  =  2.35 GPa. This work yields an upper limit for the change in Ce-valence and suggests that the critical valence fluctuation scenario, in its current form, is unlikely.

New developments in high pressure x-ray spectroscopy beamline at High Pressure Collaborative Access Team

The 16 ID-D (Insertion Device - D station) beamline of the High Pressure Collaborative Access Team at the Advanced Photon Source is dedicated to high pressure research using X-ray spectroscopy techniques typically integrated with diamond anvil cells. The beamline provides X-rays of 4.5-37 keV, and current available techniques include X-ray emission spectroscopy, inelastic X-ray scattering, and nuclear resonant scattering. The recent developments include a canted undulator upgrade, 17-element analyzer array for inelastic X-ray scattering, and an emission spectrometer using a polycapillary half-lens. Recent development projects and future prospects are also discussed.

Focusing polycapillary to reduce parasitic scattering for inelastic x-ray measurements at high pressure

The double-differential scattering cross-section for the inelastic scattering of x-ray photons from electrons is typically orders of magnitude smaller than that of elastic scattering. With samples 10-100 μm size in a diamond anvil cell at high pressure, the inelastic x-ray scattering signals from samples are obscured by scattering from the cell gasket and diamonds. One major experimental challenge is to measure a clean inelastic signal from the sample in a diamond anvil cell. Among the many strategies for doing this, we have used a focusing polycapillary as a post-sample optic, which allows essentially only scattered photons within its input field of view to be refocused and transmitted to the backscattering energy analyzer of the spectrometer. We describe the modified inelastic x-ray spectrometer and its alignment. With a focused incident beam which matches the sample size and the field of view of polycapillary, at relatively large scattering angles, the polycapillary effectively reduces parasitic scattering from the diamond anvil cell gasket and diamonds. Raw data collected from the helium exciton measured by x-ray inelastic scattering at high pressure using the polycapillary method are compared with those using conventional post-sample slit collimation.

Neonatal invasive fungal infection in England 2004-2010

Rates of invasive fungal infection are highest among neonates, especially those of low birthweight. This study aimed to describe the current epidemiology of invasive neonatal fungal infections in a UK neonatal infection surveillance network. From 2004 to 2010 prospective multicentre surveillance was conducted by 14 neonatal units using a web-based database. Clinicians then completed a standardized pro forma for each positive fungal blood and/or cerebrospinal fluid culture. The overall incidence was 2.4/1000 neonatal unit admissions and was highest among babies <1000 g (extreme low birthweight, 18.8/1000). Only five infants (6%) were >1500 g. The majority of infections were caused by Candida albicans (59; 69%) and Candida parapsilosis (17; 20%); 33% of infants had received antifungal prophylaxis. Known risk factors (use of central venous catheter, parenteral nutrition, previous antibiotic use) were common among cases. The attributable case fatality rate was 21% (18/84). Extreme low birthweight infants remain at highest risk of invasive fungal infection and prophylaxis should be particularly considered for this group. The number needing to receive prophylaxis to prevent one case varies significantly among units, hence unit-specific decisions are required. Further research is still needed into the optimal empiric and therapeutic strategies.

Magnetic and structural transitions of SrFe2As2 at high pressure and low temperature

One of key issues in studying iron based superconductors is to understand how the magnetic phase of the parent compounds evolves. Here we report the systematic investigation of paramagnetic to antiferromagnetic and tetragonal to orthorhombic structural transitions of “122” SrFe₂As₂ parent compound using combined high resolution synchrotron Mössbauer spectroscopy and x-ray diffraction techniques in a cryogenically cooled high pressure diamond anvil cell. It is found that although the two transitions are coupled at 205 K at ambient pressure, they are concurrently suppressed to much lower temperatures near a quantum critical pressure of approximately 4.8 GPa where the antiferromagnetic state transforms into bulk superconducting state. Our results indicate that the lattice distortions and magnetism jointly play a critical role in inducing superconductivity in iron based compounds.

A versatile medium-resolution x-ray emission spectrometer for diamond anvil cell applications

We present design and performance details for a polycapillary-coupled x-ray spectrometer that provides very high collection efficiency at a moderate energy resolution suitable for many studies of nonresonant x-ray emission spectroscopy, especially for samples of heavy elements under high pressures. Using a single Bragg analyzer operating close to backscattering geometry so as to minimize the effect of the weak divergence of the quasicollimated exit beam from the polycapillary optic, this instrument can maintain a typical energy resolution of 5 eV over photon energies from 5 keV to 10 keV. We find dramatically improved count rates as compared to a traditional higher-resolution instrument based on a single spherically bent crystal analyzer.

Pressure-induced valence and structural changes in YbMn2Ge2-inelastic X-ray spectroscopy and theoretical investigations

The pressure-induced valence change of Yb in YbMn(2)Ge(2) has been studied by high pressure inelastic X-ray emission and absorption spectroscopy in the partial fluorescence yield mode up to 30 GPa. The crystal structure of YbMn(2)Ge(2) has been investigated by high pressure powder X-ray diffraction experiments up to 40 GPa. The experimental investigations have been complemented by first principles density functional theoretical calculations using the generalized gradient approximation with an evolutionary algorithm for structural determination. The Yb valence and magnetic structures have been calculated using the self-interaction corrected local spin density approximation. The X-ray emission results indicate a sharp increase of Yb valence from v = 2.42(2) to v = 2.75(3) around 1.35 GPa, and Yb reaches a near trivalent state (v = 2.95(3)) around 30 GPa. Further, a new monoclinic P1 type high pressure phase is found above 35 GPa; this structure is characterized by the Mn layer of the ambient (I4/mmm) structure transforming into a double layer. The theoretical calculations yield an effective valence of v = 2.48 at ambient pressure in agreement with experiment, although the pure trivalent state is attained theoretically at significantly higher pressures (above 40 GPa).

Real-time, high-resolution x-ray diffraction measurements on shocked crystals at a synchrotron facility

The Advanced Photon Source (APS) at Argonne National Laboratory was used to obtain real-time, high-resolution x-ray diffraction measurements to determine the microscopic response of shock-compressed single crystals. Disk shaped samples were subjected to plane shock wave compression by impacting them with half-inch diameter, flat-faced projectiles. The projectiles were accelerated to velocities ranging between 300 and 1200 m/s using a compact powder gun designed specifically for use at a synchrotron facility. The experiments were designed to keep the sample probed volume under uniaxial strain and constant stress for a duration longer than the 153.4 ns spacing between x-ray bunches. X-rays from a single pulse (<100 ps duration) out of the periodic x-ray pulses emitted by the synchrotron were used for the diffraction measurements. A synchronization and x-ray detection technique was developed to ensure that the measured signal was obtained unambiguously from the desired x-ray pulse incident on the sample while the sample was in a constant uniaxial strain state. The synchronization and x-ray detection techniques described can be used for a variety of x-ray measurements on shock compressed solids and liquids at the APS. Detailed procedures for applying the Bragg-Brentano parafocusing approach to single crystals at the APS are presented. Analytic developments to determine the effects of crystal substructure and non-ideal geometry on the diffraction pattern position and shape are presented. Representative real-time x-ray diffraction data, indicating shock-induced microstructural changes, are presented for a shock-compressed Al(111) sample. The experimental developments presented here provided, in part, the impetus for the Dynamic Compression Sector (DCS) currently under development at the APS. Both the synchronization∕x-ray detection methods and the analysis equations for high-resolution single crystal x-ray diffraction can be used at the DCS.

X-ray emission spectroscopy of cerium across the γ-α volume collapse transition

High-pressure x-ray emission measurements are used to provide crucial evidence in the longstanding debate over the nature of the isostructural (α, γ) volume collapse in elemental cerium. Extended local atomic model calculations show that the satellite of the Lγ emission line offers direct access to the total angular momentum observable (J(2)). This satellite experiences a 30% steplike decrease across the volume collapse, validating the Kondo model in conjunction with previous measurements. Direct comparisons are made with previous predictions by dynamical mean field theory. A general experimental methodology is demonstrated for analogous work on a wide range of strongly correlated f-electron systems.

A miniature X-ray emission spectrometer (miniXES) for high-pressure studies in a diamond anvil cell

Core-shell X-ray emission spectroscopy (XES) is a valuable complement to X-ray absorption spectroscopy (XAS) techniques. However, XES in the hard X-ray regime is much less frequently employed than XAS, often as a consequence of the relative scarcity of XES instrumentation having energy resolutions comparable with the relevant core-hole lifetimes. To address this, a family of inexpensive and easily operated short-working-distance X-ray emission spectrometers has been developed. The use of computer-aided design and rapid prototype machining of plastics allows customization for various emission lines having energies from ∼3 keV to ∼10 keV. The specific instrument described here, based on a coarsely diced approximant of the Johansson optic, is intended to study volume collapse in Pr metal and compounds by observing the pressure dependence of the Pr Lα emission spectrum. The collection solid angle is ∼50 msr, roughly equivalent to that of six traditional spherically bent crystal analyzers. The miniature X-ray emission spectrometer (miniXES) methodology will help encourage the adoption and broad application of high-resolution XES capabilities at hard X-ray synchrotron facilities.

The Joint Asia Diabetes Evaluation (JADE) Program: a web-based program to translate evidence to clinical practice in Type 2 diabetes

AIMS

The Joint Asia Diabetes Evaluation (JADE) Program is the first web-based program incorporating a comprehensive risk engine, care protocols, clinical decision and self-management support to improve ambulatory diabetes care. The aim was to validate the risk stratification system of the JADE Program using a large prospective cohort.

METHODS

The JADE interactive risk engine stratifies patients into different risk levels using results from an annual comprehensive assessment of complications and risk factors. We used a prospective registry consisting of 7534 Type 2 diabetic patients [45.6% men, median (range) age 57 years (13-92)] to perform internal validation of the risk engine.

RESULTS

The JADE Risk Engine categorized patients into four risk levels (from low to high): level 1, n = 4520 (6%); level 2, n = 1468 (19.5%); level 3, n = 4476 (59.4%); and level 4, n = 1138 (15.1%). After a median follow-up period of 5.5 years (mean +/- sd 5.4 +/- 2.81 years), 763 (10.1%) died, 1129 (14.9%) developed cardiovascular disease (CVD), 282 (3.7%) developed end-stage renal disease and 1400 (18.6%) had at least one of these events. Compared with risk level 1, levels 2, 3 and 4 were associated with 2.8-, 4.7- and 8.6-fold increased risk of clinical end-points. Risk levels 3 and 4 were, respectively, associated with 2.2- and 3.9-fold increased risk for all-cause death and 4.8- and 12.1-fold increased CVD risks.

CONCLUSION

Based on results from a comprehensive assessment, the JADE Risk Engine successfully categorizes patients into different risk levels to guide clinical management.

Mistaken identity of skin cleansing solution leading to extensive chemical burns in an extremely preterm infant

Chemical burns in extremely preterm infants have major implications in terms of morbidity and risk management. We report a case of extensive chemical burn in an extremely low birth weight (ELBW) infant caused by clear, colourless solution of 0.5% chlorhexidine in 70% alcohol mistaken for normal saline for skin cleansing during umbilical catheter insertion. This case reflects the on going problem faced by many neonatal intensive care units of similar coloured solutions with similar packages, but with varying degrees of toxic effects.

CONCLUSION

The case highlights the importance of having a clear policy for skin cleansing in every neonatal unit and measures to avoid errors by vigilant checking of all medications including topical solutions.

Preoperative airway management in a preterm with bilateral choanal atresia

Bilateral choanal atresia (CA) is a recognized neonatal emergency. Before corrective surgery, provision of a secure airway is crucial. No approach has been specifically advocated for preterm infants. We describe successful use of a novel airway in a preterm infant with CA.

Absence of magnetism in hcp iron-nickel at 11 K

Synchrotron Mössbauer spectroscopy (SMS) was performed on an hcp-phase alloy of composition Fe92Ni8 at a pressure of 21 GPa and a temperature of 11 K. Density functional theoretical calculations predict antiferromagnetism in both hcp Fe and hcp Fe-Ni. For hcp Fe, these calculations predict no hyperfine magnetic field, consistent with previous experiments. For hcp Fe-Ni, however, substantial hyperfine magnetic fields are predicted, but these were not observed in the SMS spectra. Two possible explanations are suggested. First, small but significant errors in the generalized gradient approximation density functional may lead to an erroneous prediction of magnetic order or of erroneous hyperfine magnetic fields in antiferromagnetic hcp Fe-Ni. Alternately, quantum fluctuations with periods much shorter than the lifetime of the nuclear excited state would prohibit the detection of moments by SMS.

4f delocalization in Gd: inelastic x-ray scattering at ultrahigh pressure

We present resonant inelastic x-ray scattering and x-ray emission spectroscopy results on Gd metal to 113 GPa which suggest Kondo-like aspects in the delocalization of 4f electrons. Analysis of the resonant inelastic x-ray scattering data reveals a prolonged and continuous delocalization with volume throughout the entire pressure range, so that the volume-collapse transition at 59 GPa is only part of the phenomenon. Moreover, the Lgamma1 x-ray emission spectroscopy spectra indicate no apparent change in the bare 4f moment across the collapse, suggesting that Kondo screening is responsible for the expected Pauli-like behavior in magnetic susceptibility.

Childhood sleep-disordered breathing and its implications for cardiac and vascular diseases

OBJECTIVE

To systematically evaluate the recent literature regarding the relationship between childhood sleep-disordered breathing (SDB)/obstructive sleep apnoea (OSA) and cardiovascular diseases in children.

METHODS

The literature about SDB/OSA and blood pressure, sympathetic activation, arterial distensibility, ventricular hypertrophy and insulin resistance were studied. Meta-analysis of risk of hypertension and high apnoea-hyponoea index were performed to calculate the combined odds ratio and it is equal to 2.93 (95% CI = 1.18-7.29).

RESULTS

The results suggest a significant association between SDB/OSA and hypertension. However, the data are not adequate to draw firm conclusion although evidences were emerging to suggest that SDB/OSA affects blood pressure in either directions in children. Limited evidences also suggest that SDB/OSA is associated with increased sympathetic activation, decreased arterial distensibility and ventricular hypertrophy.

CONCLUSIONS

There is now increasing but not adequate evidence that childhood SDB/OSA is associated with detectable cardiovascular abnormalities.

New cubic phase of Li3N: stability of the N3- ion to 200 GPa

Diamond-anvil cell experiments augmented by first-principles calculations have found a remarkable stability of the N(3-) ion in Li3N to a sixfold volume reduction. A new (gamma) phase is discovered above 40(+/-5) GPa, with an 8% volume collapse and a band gap quadrupling at the transition determined by synchrotron x-ray diffraction and inelastic x-ray scattering. gamma-Li(3)N (Fm3m, Li(3)Bi-like structure) remains stable up to 200 GPa, and calculations do not predict metallization until approximately 8 TPa. The high structural stability, wide band gap, and simple electronic structure make this N(3-) based system analogous to lower valency compounds (MgO, NaCl, Ne), meriting its use as an internal pressure standard.

Extracellular signal-regulated kinase induces cyclin D1 and Cdk-2 expression and phosphorylation of retinoblastoma in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies in Southeast Asia. Hyperphosphorylation of retinoblastoma (pRB) by cyclin/CDKs in G1/S transition is required for its inactivation and cell cycle progression. In the present study, we report that phosphorylation of pRB at Ser780 and Ser795 was detected in 71% (33 of 46) and 63% (29 of 46) of HCCs examined respectively. pRB protein was undetectable in 13% (6 of 46) of HCCs examined. Phosphorylated pRB was localized in the nuclei of hepatocarcinoma cells. Benign hepatocytes exhibited very weakly or no nuclear staining for phosphorylated pRB. Over-expression of E2F-1, cyclin D1, Cdk-2, Cdk-4 and cyclin A was found in 64% (30 of 46), 43% (26 of 46), 28% (11 of 46), 71% (33 of 46) and 63% (29 of 46) of HCCs examined respectively and this was correlated with elevation of ERK. Treatment of HepG2 cells with MEK1/2 inhibitor U0126 resulted in cell cycle arrest, downregulation of cyclin D1 and Cdk-2 expression and inhibition of pRB phosphorylation at Ser780 and Ser795. Ectopic expression of activated MEK1 in HepG2 cells increased cyclin D1 and Cdk-2 expression, phosphorylation of pRB at Ser780 and Ser795, and percentage of cells in S phase. Our data indicate that activated ERK plays an important role in cyclin D1 and Cdk-2 expression and phosphorylation of pRB at Ser780 and Ser795 in liver cancer cells.

First-order isostructural Mott transition in highly compressed MnO

We present evidence for an isostructural, first-order Mott transition in MnO at 105+/-5 GPa, based on high-resolution x-ray emission spectroscopy and angle-resolved x-ray diffraction data. The pressure-induced structural and spectral changes provide a coherent picture of MnO phase transitions from paramagnetic B1 to antiferromagnetic distorted B1 at 30 GPa, to paramagnetic B8 at 90 GPa, and to diamagnetic B8 at 105+/-5 GPa. The last is the Mott transition, accompanied by a significant loss of magnetic moment, an approximately 6.6% volume collapse and the insulator-metal transition as demonstrated by recent resistance measurements.

MARS therapy in critically ill patients with advanced malignancy: a clinical and technical report

BACKGROUND/METHODS

Molecular Adsorbent Recirculating System (MARS) was used in three consecutive critically ill patients at the Singapore General Hospital with advanced malignancy and acute liver failure (ALF). Case 1 was a male patient with hepatocellular carcinoma (HCC) for which initial right hepatectomy was followed by left hepatectomy 5 months later for recurrent HCC. The postoperative course following second surgery was complicated by severe methicillin-resistant Staphylococcus aureus (MRSA) sepsis, mild azotaemia and subacute cholestatic liver failure. MARS was used thrice in this patient. Case 2 was a female patient with advanced acute lymphoblastic leukaemia (ALL) with post bone marrow transplantation (BMT) acute haemolytic-uraemic syndrome (HUS) secondary to cyclosporin A (Cy A), cytomegalovirus (CMV) infection, severe nosocomial pneumonia, acute renal failure (ARF) treated with continuous haemofiltration and acute veno-occlusive disease resulting in Budd-Chiari syndrome. The latter precipitated ALF. MARS was instituted twice. Case 3 was a male patient with advanced, refractory Hodgkin's disease previously treated with multiple courses of chemotherapy. ALF developed secondary to acute viral hepatitis B flare. He was given a trial of MARS once in the ICU. All the three patients eventually died.

RESULTS

Mean MARS intradialytic systemic pressures were as follows: systolic pressure range was 95 +/- 17 to 128 +/- 17 mmHg and diastolic pressure range was 51 +/- 5 to 67 +/- 7 mmHg. Pressure at albumin dialysate exit point from dialyser 1 (Ae) ranged from 253 +/- 11 to 339 +/- 15 mmHg and that at albumin dialysate entry point into dialyser 1 (Aa) ranged from 142 +/- 11 to 210 +/- 6 mmHg. Ultrafiltration (UF) was 633 +/- 622 mL over mean treatment duration of 6.3 +/- 0.9 h with a total heparin dose of 1583 +/- 817 IU. Coagulation status pre- and 6-h post-MARS was similar: aPTT (P=0.116) and platelet count (P=0.753). There were no bleeding complications or circuit thromboses. MARS had a significant de-uraemization effect (pre- and post-MARS serum creatinine and urea: P=0.046 and 0.028, respectively) but did not significantly attenuate blood lactate, ammonia or total bilirubin levels. Albumin dialysate (Ae - Aa) urea and creatinine concentrations appeared to be sharply attenuated after 6 h of MARS. In contrast, the removal of total bilirubin by albumin dialysate from the blood compartment appeared to plateau after 4 h of continuous MARS operation.

CONCLUSIONS

MARS was well-tolerated in critically ill patients with advanced and complicated cancer. Low-dose heparin was safe and did not compromise MARS circuit integrity. Although MARS had a significant de-uraemization effect, this appeared to be limited by the duration of MARS operation. Our data suggested that such a limit was reached earlier for total bilirubin. More data are needed to confirm the present findings and further delineate the saturation limit of MARS for different toxins that accumulate in ALF. This would affect the optimal duration of MARS therapy.

The tree shrews: adjuncts and alternatives to primates as models for biomedical research

The tree shrews are non-rodent, primate-like, small animals. There is increasing interest in using them to establish animal models for medical and biological research. This review focuses on the use of the tree shrews in in vivo studies on viral hepatitis, hepatocellular carcinoma (HCC), myopia, and psychosocial stress. Because of the susceptibility of the tree shrews (Tupaia belangeri) and their hepatocytes to infection with human hepatitis B virus (HBV) in vivo and in vitro, these animals have been used to establish human hepatitis virus-induced hepatitis and human HBV- and aflatoxin B1-associated HCC models. As these animals are phylogenetically close to primates in evolution and have a well-developed visual system and color vision in some species, they have been utilized to establish myopia models. Because dramatic behavioral, physiological, and neuroendocrine changes in subordinate male tree shrews are similar to those observed in depressed human patients, the tree shrews have been successfully employed to experimentally study psychosocial stress. However, the tree shrews holds significant promise as research models and great use could be made of these animals in biomedical research.

Chorioamnionitis and outcome in extremely preterm infants

INTRODUCTION

Chorioamnionitis is a risk factor for preterm delivery. Intrauterine infection leads to the fetal inflammatory response which is characterised by elevated cytokine levels. Chorioamnionitis is reported to cause accelerated but abnormal lung maturation, resulting in decreased incidence of respiratory distress syndrome (RDS) but increased chronic lung disease (CLD), and predisposes the infant to cerebral injury.

OBJECTIVE

To investigate the relation between chorioamnionitis and RDS, CLD, cerebral lesions, neurodevelopmental outcome and mortality in a cohort of extremely premature infants.

MATERIALS AND METHODS

Infants born between 1997 and 2001 with a gestational age of less than 28 weeks or a birth weight of less than 1000 g were divided into two groups: Group 1 with evidence of chorioamnionitis and Group 2 without. Outcomes of these two groups of infants were compared.

RESULTS

A total of 388 infants were included (105 in Group 1 and 283 in Group 2). Chorioamnionitis was significantly associated with an increased risk of extreme preterm delivery. Group 1 showed a trend towards an increased incidence of CLD and mortality, while the incidence of periventricular leukomalacia, retinopathy of prematurity (ROP) and necrotising enterocolitis (NEC) were similar between the two groups. Subgroup analysis of 2-year neurodevelopmental outcome showed an increased trend towards cerebral palsy and visual impairment, while the incidence of developmental delay and hearing impairment are similar between the two groups.

CONCLUSION

Extremely preterm infants with chorioamnionitis showed a trend towards an increased incidence of CLD, mortality, cerebral palsy and visual impairement, but a decreased risk of RDS.

Expertise sensitive item selection

In this paper we describe and illustrate a procedure for selecting items from a large pool for a certification test. The proposed procedure, which is intended to improve the alignment of the certification test with on-the-job performance, is based on an expertise sensitive index. This index for an item is the difference between the item's p values for experts and novices. An example is provided of the application of the index for selecting items to be used in certifying bakers.

Respiratory monitoring using an air-mattress system

This paper describes a non-invasive respiratory monitoring system using an air mattress. The air-mattress system features multiple air compartments to monitor movements of the thorax and the abdomen separately. To evaluate the performance of the air-mattress system, four subjects were selected for the study and their separate ribcage and abdominal movements were monitored simultaneously by respiratory inductive phlethysmography belts and the air-mattress system. The sensitivity and accuracy indices of the air-mattress system for the detection of hypopnoeas scored remarkably well (above 90%). In addition, it was noted that the mean error in the measurement of the respiratory rate between the two systems was very small. This paper shows that the air-mattress system can be a reliable non-invasive respiratory monitoring system to detect simple abnormalities in breathing, such as respiration rate and hypopnoeas.

Preliminary development of the Body Image Affect Scale

A new body-image questionnaire was developed to measure the affect associated with a negative body image. Responses showed a Cronbach coefficient alpha of .84 and a negative correlation of -.21 with using humor in times of stress.

A comparative study on the efficacy of CD8-positive cells in enhancing allogeneic bone marrow engraftment: cell sorting vs microbead selection

We have used a superparamagnetic microbead selection system to positively select a murine bone marrow CD8+ cell population. The functional ability of these cells to enhance allogeneic bone marrow engraftment was compared with that of fluorescence activated cell sorter purified CD8+ cells. The CD8+ cell population prepared by the microbead selection procedure was as effective as cell sorter purified CD8+ cells in enhancing T cell-depleted allogeneic bone marrow engraftment in lethally irradiated mice. Phenotypic characterization of these cells shows that most of these CD8+ cells express CD3 and the T cell antigen receptor complex.

Normal subjects consuming physiological levels of 18:3(n-3) and 20:5(n-3) from flaxseed or fish oils have characteristic differences in plasma lipid and lipoprotein fatty acid levels

The study assessed the effect of low doses of fatty acids from fish or flaxseed oil on plasma lipid concentrations in normal humans consuming diets with either high (0.87, n = 11) or low (0.48, n = 15) dietary polyunsaturated/saturated fatty acid (P/S) ratios. The dose of (n-3) fatty acids reflected an (n-3) intake that could easily be attained by selection of foods in a normal diet. The individuals were initially supplemented with olive oil [35 mg 18:1/(kg body weight.d)], and then were randomly assigned to either flaxseed or fish oil [35 mg 18:3(n-3) or 35 mg 20:5(n-3) + 22:6(n-3)/(kg body weight.d), respectively] treatments. Participants consumed each oil supplement for 3 mo. Blood samples were drawn for analysis at the end of each 3-mo period. Plasma triacylglycerol, total, LDL and HDL cholesterol concentrations, and lipoprotein fatty acid concentrations are shown. Fish oil reduced plasma triacylglycerol and increased lipoprotein levels of 20:5(n-3) and 22:6(n-3). The flaxseed oil did not alter plasma triacylglycerol level and produced small changes in 20:5(n-3) and 22:6(n-3) concentrations. Total, LDL and HDL cholesterol levels were not affected by either (n-3) fatty acid. Significant differences in plasma triacylglycerol concentrations and total and LDL cholesterol levels were found between the two dietary P/S groups after all oil treatment periods. Levels of 18:3(n-3), 20:4(n-6), 20:5(n-3), and 22:6(n-3) in LDL were also different in high vs. low dietary P/S groups for all oil treatments and in the VLDL for the olive oil and fish oil supplementation. This study indicates that low intake of purified fish oil induces changes in plasma triacylglycerol, 20:5(n-3) levels in VLDL, LDL, and HDL, and 22:6(n-3) levels in LDL and HDL that are apparent after 3 mo and which might influence atherogenicity of lipoprotein particles in normal free-living individuals.

The ethnic elderly in Metro Toronto Hospitals, nursing homes, and homes for the aged: communication and health care

The ethnic elderly in Canada have remained a somewhat isolated group of seniors who become known when they enter our health care system as "aliens in their own country." They face the double jeopardy of not only declining sensibilities and increasing disabilities that frequently accompany old age but also the psycho-social deprivation of being unable to communicate with caregivers in their institutional health care settings. Communication may be critical to effective, efficient, and equitable health care service delivery for ethnic elderly individuals. This study attempts to develop a database on the ethnic elderly persons, examine the extent of communication problems they face in hospitals, nursing homes, and homes for the aged in Metro Toronto, and report on the institutional responses to the situation. Nursing unit supervisors who completed the questionnaires (N = 77) reported that communication was essential to the health care needs of the ethnic elderly individuals. A majority of health care institutions had developed some form of interpreter services albeit frequently informal, unprofessional, and ad hoc. Without interpreter services problems developed that in some cases were seen as critical to the health care of ethnic elderly individuals. Even with interpreter services available, problems developed, suggesting that the services provided were not effective in some cases. It is suggested that further study be conducted to examine the relative effectiveness of formal, professional, and informal interpreter services. Few institutions had workshops or training to help staff understand ethnic variations on the perceptions of illness and health.

Clinical profile of stage D carcinoma of the prostate--a ten-year experience

Carcinoma of the prostate has become one of the top ten malignancies in Singapore but to date, there has been little local clinical data available on the disease. This study aims to establish the clinical profile of Stage D carcinoma of the prostate in the local population. Forty-seven patients with Stage D disease treated by the department over a ten-year period, 1981-90, were studied. The majority (47.7%) fell in the age-group 66-75 years and the most common presenting symptom was bone pain (36.2%). Both acid and alkaline phosphatases were found to be poor diagnostic markers of the extent of the disease. Acid phosphatase was not elevated in 25.0% and alkaline phosphatase not elevated in 39.1% of our patients. Forty of these patients had orchidectomy and of these, ten were also treated with oral stilbesterol. Five-year survival for the orchidectomy group was 22.7% and that for the orchidectomy-plus-stilbesterol group was 23.0%. This compares well with other studies done in the West. Eight patients died within the first year of diagnosis but of those who survived, all remained symptom-free within this first year. The proportion of those who remained symptom-free fell to 25.0% of the survivors for subsequent years.

Multiple basal cell carcinoma in tropical Australia

No association between HLA DR1 and the development of multiple basal cell carcinomas (BCC) was found among patients who had lived at least two-thirds of their lives in the tropics. The percentage of patients with multiple BCCs increased with age; this was different from what has been found in people living in the temperate zone of Australia.