Changes in Navigation Controls and Field-of-View Modes Affect Cybersickness Severity and Spatiotemporal Gait Patterns After Exposure to Virtual Environments.

OBJECTIVE: To examine the effects of navigation controls and field-of-view modes on cybersickness severity and gait dynamics after cessation of exposure to a virtual environment (VE). BACKGROUND: The applications of virtual reality are increasing in various fields; however, whether changes in interaction techniques and visual contents could mitigate the potential gait disturbance following VE exposure remains unclear. METHOD: Thirty healthy adults wore a head-mounted display to complete six sessions of 12-min run-and-gun tasks using different navigation controls (gamepad, head, natural) and field-of-view modes (full, restricted). Forward and backward walking tasks were performed before and after VE exposure. The degrees of cybersickness and presence were evaluated using questionnaires, along with the in-session task performance. Spatiotemporal gait measures and their variabilities were calculated for each walking task. RESULTS: The participants experienced less cybersickness with the head and natural controls than with the gamepad. Natural control, based on matching body movements, was associated with the highest degree of presence and best performance. VE navigation using the gamepad showed reduced cadences and increased stride times during postexposure forward-walking tasks. When the VE was presented via the restricted field-of-view mode, increased gait variabilities were observed from backward-walking tasks after VE exposure. CONCLUSION: Body movement-based navigation controls may alleviate cybersickness. We observed gait adaptation during both ambulation tasks, which was influenced by the navigation control method and field-of-view mode. APPLICATION: This study provides the first evidence for gait adaptation during balance-demanding tasks after VE exposure, which is valuable for designing guidelines for virtual reality interactions.

Cumulative incidence of urinary incontinence and associated factors during pregnancy and after childbirth: a cohort study.

INTRODUCTION AND HYPOTHESIS: This study examined the associated factors (i.e., obstetric and maternal-newborn factors) related to cumulative incidence of urinary incontinence and changes in urinary incontinence during pregnancy and the first year postpartum. METHODS: This prospective, longitudinal, within-subject study included 501 women who completed the Incontinence Questionnaire-Urinary Incontinence Short Form during pre-pregnancy, early pregnancy, mid-pregnancy, and late pregnancy and at five time points during the first year postpartum. Data were analyzed by multivariate logistic regression, McNemar's and analysis of variance (ANOVA) tests. RESULTS: According to the multivariate analysis, the gestational week and number of previous vaginal deliveries increased the risk of cumulative incidence of urinary incontinence (CIUI) during pregnancy (both p < 0.05). Full-time employment, higher body mass index, vaginal delivery and UI during early pregnancy and mid-pregnancy increased the risk of CIUI during the first year postpartum (all p < 0.05). CIUI tended to increase throughout the entire pregnancy (p < 0.001) and decrease from 3 to 5 days to 6 months postpartum (p = 0.028). The prevalence rates of UI at all postpartum visits were lower than those during late pregnancy (p < 0.001-0.009) but higher than those during pre-pregnancy (p < 0.001). CONCLUSIONS: The results identified the change patterns in UI and the risk factors associated with CIUI during the entire pregnancy (i.e., gestational age and number of previous vaginal deliveries) and the first year postpartum (i.e., full-time work, higher body mass index, vaginal delivery and UI during early and mid-pregnancy). Appropriate counseling should be provided to women preparing for pregnancy and during the prenatal and postpartum periods.

Use of an inflatable mat to reduce body discomfort development when performing computer work at a standing desk.

This study aimed to determine the effects of inflatable mat design on body discomfort, task performance, and musculoskeletal exposures during standing computer work. Twenty-seven healthy adults completed three 2-hour standing trials on different mediums (concrete floor, foam mat, and inflatable mat) on different days in an experimental laboratory. Both mats were associated with reduced discomfort in all lower-body regions and increased typing performance compared to the concrete floor. Perceived discomfort in lower extremities (except thighs) was further alleviated while standing on the inflatable mat than on the foam mat. Use of the inflatable mat led to increased lower-body muscle activity, a flexed lower back, and a wide range of sagittal knee movements. As standing time increased, body discomfort increased, typing accuracy decreased, and there were increased variations in muscle activity and postural movements in the lower body. The inflatable mat shows potential to improve the ergonomic experience during prolonged standing. Practitioner summary: Incorporating standing postures in office-based workplaces can reduce sitting time and may mitigate the health hazards associated with sedentary behaviour. With adequate weight-shifting movements, using an inflatable mat for standing could be an effective way to lessen discomfort and accumulated musculoskeletal strain due to constrained standing, without jeopardising task productivity. Abbreviations: APDF: amplitude probability distribution function. AVR: average rectified value. CI: confidence interval. CMRR: common mode rejection ratio. COP: center of pressure. CV: coefficient of variation. EA: electrical activity. EMG: electromyography. FL: fibularis longus. GM: gluteus medius. LBP: lower back pain. LES: lumbar erector spinae. MVC: maximum voluntary contraction. PD: pain developer. rANOVA: repeated-measures analysis of variance. SOL: soleus. VAS: visual analog scale. WPM: words per minute.

Risk factors for stress and urge urinary incontinence during pregnancy and the first year postpartum: a prospective longitudinal study.

INTRODUCTION AND HYPOTHESIS: We examined obstetric and maternal-newborn factors and UI history for stress urinary incontinence (UI) and urge UI during pregnancy and the first year postpartum. METHODS: This prospective cohort study included 1447 pregnant women who underwent prenatal examinations and completed an Incontinence Questionnaire-Urinary Incontinence Short Form before pregnancy, during early, mid- and late pregnancy, and at five visits during the first year postpartum. Data were analyzed using univariate/multivariate generalized estimating equation (GEE) logistic regression analyses. RESULTS: The prevalence rates of stress UI during late pregnancy (42.5%) and urge UI at 3-5 days postpartum (10.4%) were the highest throughout pregnancy and the first year postpartum. After adjusting for covariates, gestational age increased the risks of stress UI (p < 0.001) and urge UI (p = 0.003); stress UI during pre-pregnancy, number of previous vaginal deliveries and concurrent high body mass index (BMI) increased stress UI (all p < 0.05); urge UI during pre-pregnancy and full-time work increased urge UI (both p < 0.05) during pregnancy. During the postpartum period, vaginal delivery increased stress UI (p < 0.001) and urge UI (p = 0.041); stress UI during pre-pregnancy and pregnancy, women aged ≥ 30 years and vacuum extraction/forceps delivery increased stress UI (all p < 0.05). Urge UI during early, mid- and late pregnancy increased stress UI (all p < 0.05). CONCLUSIONS: Gestational age increased stress and urge UI, while previous vaginal deliveries and high BMI increased stress UI; full-time work increased urge UI during pregnancy. Vaginal delivery increased both UIs, and vacuum/forceps delivery and maternal age increased stress UI during postpartum.

Combined effect of polymorphisms of MTHFR and MTR and arsenic methylation capacity on developmental delay in preschool children in Taiwan.

Polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR) are related to cognitive dysfunction and mental disability. These genes, along with folate and vitamin B12 levels, are regulators of one-carbon metabolism, which synthesizes S-adenosylmethionine (SAM) as a methyl donor for arsenic methylation. The aim of this study was to explore whether polymorphisms of MTHFR and MTR influence arsenic methylation capacity and plasma folate and vitamin B12 levels and if these influences cause developmental delay in preschool children. A total of 178 children with developmental delay and 88 without developmental delay were recruited from August 2010 to March 2014. A high-performance liquid chromatography-hydride generator and atomic absorption spectrometer were used to determine urinary arsenic species. Plasma folate and vitamin B12 concentrations were measured by SimulTRAC-SNB radioassay. Polymorphisms of MTHFR C677T, MTHFR A1298C, and MTR A2756G were examined by polymerase chain reaction and restriction fragment length variation. The results show that MTHFR C677T C/T and T/T genotypes had a lower risk of developmental delay than the C/C genotype (odds ratio [OR] = 0.47; 95% confidence interval, 0.26-0.85). Subjects with the MTHFR C677T C/C genotype had significantly lower plasma folate and vitamin B12 levels than those with the MTHFR C677T C/T and T/T genotype. The MTHFR C677T C/C genotype combined with high total urinary arsenic and poor arsenic methylation capacity indices significantly increased the OR of developmental delay in a dose-response manner. This is the first study to show the combined effect of MTHFR C677T genotype and poor arsenic methylation capacity on developmental delay.

Neuropsychiatric Disorders Due to Limbic Encephalitis: Immunologic Aspect.

Limbic encephalitis (LE) is a rare cause of encephalitis presenting as an acute and subacute onset of neuropsychiatric manifestations, particularly with memory deficits and confusion as core features, along with seizure occurrence, movement disorders, or autonomic dysfunctions. LE is caused by neuronal antibodies targeting the cellular surface, synaptic, and intracellular antigens, which alter the synaptic transmission, especially in the limbic area. Immunologic mechanisms involve antibodies, complements, or T-cell-mediated immune responses in different degree according to different autoantibodies. Sensitive cerebrospinal fluid markers of LE are unavailable, and radiographic findings may not reveal a typical mesiotemporal involvement at neurologic presentations; therefore, a high clinical index of suspicions is pivotal, and a neuronal antibody testing is necessary to make early diagnosis. Some patients have concomitant tumors, causing paraneoplastic LE; therefore, tumor survey and treatment are required in addition to immunotherapy. In this study, a review on the molecular and immunologic aspects of LE was conducted to gain awareness of its peculiarity, which we found quite different from our knowledge on traditional psychiatric illness.

Influence of virtual keyboard design and usage posture on typing performance and muscle activity during tablet interaction.

This study aimed to determine the effects of virtual keyboard designs and postures on task performance and muscle activity during tablet use. Eighteen healthy adults were randomly assigned to one of three postures (DESK, LAP, BED) to complete six sessions of 60-minute typing on a tablet with three virtual keyboards (STD, WIDE, SPLIT) twice in an experimental laboratory. Keystroke dynamics and muscle activity of the forearm and neck-shoulder regions were measured by electromyography. The split virtual keyboard was found to be associated with faster typing speed (SPLIT vs STD, p = .015; SPLIT vs WIDE, p < .001) and decreased muscle activity of extensor digitorum communis (SPLIT vs STD, p = .021). Lap posture was associated with faster typing speed (p = .018) and higher forearm muscle activity (p < .05). Typing performance decreased (p < .001) with elevated neck extensor muscle activity (p = .042) when the task duration prolonged. The split virtual keyboard showed potential to improve tablet ergonomics under various postures. Practitioner Summary: Tablets have become widely used for a variety of tasks and have gradually expanded into the realm of mobile productivity and education. Adequate designs of virtual keyboards for tablets show the potential for increased task performance and decreased muscle activity pertinent to typing activity and posture constraints imposed by non-traditional work positions. Abbreviations: WPM: words per minute; IKI: inter-key press interval; EMG: electromyography; EDC: extensor digitorum communis; FDS: flexor digitorum superficialis; CES: cervical erector spinae; UT: upper trapezius; EA: electrical activity; MVC: maximum voluntary contraction; APDF: amplitude probability distribution function.

Plasma selenium influences arsenic methylation capacity and developmental delays in preschool children in Taiwan.

Inefficient arsenic methylation capacity has been associated with developmental delay in preschool children. Selenium has antioxidant and anti-inflammatory properties that protect experimental animals from chemically induced neurotoxicity. The present study was designed to explore whether plasma selenium levels affects arsenic methylation capacity related to developmental delay in preschool children. A case-control study was conducted from August 2010 to March 2014. All participants were recruited from the Shin Kong Wu Ho-Su Memorial Teaching Hospital. In total, 178 children with a developmental delay and 88 children without a delay were recruited. High-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry were used to determine urinary arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV). Plasma selenium levels were measured by inductively coupled plasma mass spectrometry. As results, plasma selenium concentration was significantly inversely associated with the odds ratio (OR) of developmental delay. Plasma selenium concentration was positively associated with arsenic methylation capacity [percentage of inorganic arsenic and percentage of MMAV (MMAV%) decreased, and percentage of DMAV (DMAV%) increased]. High plasma selenium concentration and high DMA% significantly and additively interacted to decrease the OR of developmental delay; the OR and 95% confidence interval were 0.40 (0.18-0.90). This is the first study to show a combined dose-response effect of plasma selenium concentration and that efficient arsenic methylation capacity decreased the OR of developmental delay in preschool children.

Association of plasma folate, vitamin B12 levels, and arsenic methylation capacity with developmental delay in preschool children in Taiwan.

Developmental delay has been associated with inefficient arsenic methylation capacity in preschool children. Folate and vitamin B12 are important nutrients that produce s-adenosylmethionine during single-carbon metabolism and provide methyl groups for arsenic methylation. The aim of the present study was to explore whether plasma folate and vitamin B12 levels influence arsenic methylation capacity and in turn are related to developmental delay in preschool children. A case-control study was conducted in 178 children with developmental delay and 88 normal children, who were recruited from Shin Kong Wu Ho-Su Memorial Teaching Hospital from August 2010 to March 2014. Arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) in the urine was determined by high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Plasma folate and vitamin B12 levels were measured using a SimulTRAC-SNB radioassay. The results show that the combination of high plasma folate and high vitamin B12 levels were correlated with efficient arsenic methylation capacity (low MMAV %, low InAs %, and high DMAV %). High MMAV % significantly increased and high DMAV % and secondary methylation index decreased the odds ratio (OR) of developmental delay in a dose-dependent manner in both low plasma folate and low vitamin B12 (low/low) groups; the multivariate OR and 95% confidence interval were 5.01 (0.83-30.06), 0.21 (0.04-1.23), and 0.20 (0.03-1.20), respectively. This is the first study to show that the combination of high plasma folate and high vitamin B12 levels increases arsenic methylation capacity and indirectly decreases the OR of developmental delay in preschool children.

Relation of polymorphism of arsenic metabolism genes to arsenic methylation capacity and developmental delay in preschool children in Taiwan.

Inefficient arsenic methylation capacity has been associated with developmental delay in children. The present study was designed to explore whether polymorphisms and haplotypes of arsenic methyltransferase (AS3MT), glutathione-S-transferase omegas (GSTOs), and purine nucleoside phosphorylase (PNP) affect arsenic methylation capacity and developmental delay. A case-control study was conducted from August 2010 to March 2014. All participants were recruited from the Shin Kong Wu Ho-Su Memorial Teaching Hospital. In total, 179 children with developmental delay and 88 children without delay were recruited. Urinary arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) were measured using a high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. The polymorphisms of AS3MT, GSTO, and PNP were performed using the Sequenom MassARRAY platform with iPLEX Gold chemistry. Polymorphisms of AS3MT genes were found to affect susceptibility to developmental delay in children, but GSTO and PNP polymorphisms were not. Participants with AS3MT rs3740392 A/G+G/G genotype, compared with AS3MT rs3740392 A/A genotype, had a significantly lower secondary methylation index. This may result in an increased OR for developmental delay. Participants with the AS3MT high-risk haplotype had a significantly higher OR than those with AS3MT low-risk haplotypes [OR and 95% CI, 1.59 (1.08-2.34)]. This is the first study to show a joint dose-response effect of this AS3MT high-risk haplotype and inefficient arsenic methylation capacity on developmental delay. Our data provide evidence that AS3MT genes are related to developmental delay and may partially influence arsenic methylation capacity.

A repeated measures study of changes in health-related quality of life during pregnancy and the relationship with obstetric factors.

AIMS: To examine changes in health-related quality of life throughout the course of pregnancy and among three pairs of consecutive periods (pre-pregnancy to early pregnancy, early to middle pregnancy and middle to late pregnancy), as well as to identify associated obstetric factors during the entire period of pregnancy. BACKGROUND: Only sparse data are available concerning the profiles of health-related quality of life throughout pregnancy. DESIGN: A within-subject comparison was undertaken. METHODS: In total, 358 women completed the Taiwanese version of the Medical Outcomes Study Short Form-36 Health Questionnaire and a demographic-obstetric questionnaire at three stages of pregnancy at a medical centre. The participants were recruited between 2009-2010. A generalized estimating equation regression model was employed for the repeated measures. RESULTS: The scores for physical component summary decreased significantly throughout early, middle and late pregnancy. The scores for mental component summary increased. The scores for physical, mental component summary and the eight domains of health-related quality of life decreased significantly from pre-pregnancy to early pregnancy. After adjusting for demographic and clinical factors, significant factors predicting physical component summary during pregnancy included stage of pregnancy and previous infertility. The factors predicting mental component summary included stage of pregnancy, parity and medical condition. CONCLUSIONS: The results revealed the dynamic pattern of perceived health status by the Taiwanese pregnant women in their surrounding socio-cultural context and identified the stage of pregnancy and obstetric factors predicting health-related quality of life.

Quality of life and impact of children with unclassified developmental delays.

AIMS: The study aims to evaluate the quality of life (QOL) and health of children with unclassified developmental delays and the impacts this had on the family. METHODS: In total, 60 parents of pre-school children with unclassified developmental delays and 56 parents of age and gender-matched children with typical development were recruited. We administered the Pediatric Quality of Life Inventory (PedsQL)-Generic Core Scale and Pediatric Outcomes Data Collection Instrument to parents to evaluate the QOL and health status of their children. Parents were evaluated by World Health Organization-Quality of Life-Brief Version, PedsQL-Family Impact Module, Hospital Anxiety and Depression Scale, and PedsQL-Health satisfaction to assess the impacts of this situation on the family. Variables related to QOL and functions of children with unclassified developmental delays were analysed by stepwise regression analysis. RESULTS: Comparing children with typical development, children with unclassified developmental delays had a significantly lower QOL (including both psychosocial and physical components) and health status. Their parents had a significantly lower QOL, family function and health satisfaction, and higher psychological distress than parents of children with typical development. Gross-motor delay impacts on QOL of these children (regression coefficient: -9.59, P < 0.05), global functioning is related to cognition delay (regression coefficient: -20.22, P < 0.01) and physical health of their parents (regression coefficient: 0.87, P < 0.01). CONCLUSIONS: Children with unclassified developmental delays had lower QOL and health status, and their condition had greater impacts on the family than children with typical development. Gross motor and cognition development related to the QOL and global functioning in these children.

Early oral-motor management on feeding performance in premature neonates.

BACKGROUND/PURPOSE: Poor oral-motor developments in premature infants are common. From the viewpoint of developmental care, most of the infants required individualized therapy. The specific aim of our study was to evaluate the effectiveness and impact of early intervention of oral-motor management on feeding pattern and the neonatal outcomes in premature neonates. METHODS: The study enrolled 68 preterm infants with birth weight less than 1500 g or gestational age less than 32 weeks. We tried to strengthen the sucking ability of infants with poor oral-motor coordination. RESULTS: There were significant differences in the body weight (g) while feeding up to 45 mL (1916 ± 156 vs. 2003 ± 191 g, p = 0.002) and hospital stay (46.3 ± 25.3 vs. 54.7 ± 23.5 days, p = 0.003) between the study and control groups. CONCLUSION: Abnormal brain sonography [odds ratio (OR): 2.222, p = 0.047) and necrotizing enterocolitis (NEC) (OR: 2.857, p = 0.017) did affect the first trial in the study group. Early intervention of oral-motor management in very-low-birth-weight premature infants improved feeding performance and neonatal outcome in terms of shorter hospital days. Abnormal brain image and NEC could interfere with the success rate of initial challenge of transitioning from tube to oral feeding in the study group.

Comparison of artificial neural network (ANN) and partial least squares (PLS) regression models for predicting respiratory ventilation: an exploratory study.

The objective of this study was to assess the potential for using artificial neural networks (ANN) to predict inspired minute ventilation (V(I)) during exercise activities. Six physiological/kinematic measurements obtained from a portable ambulatory monitoring system, along with individual's anthropometric and demographic characteristics, were employed as input variables to develop and optimize the ANN configuration with respect to reference values simultaneously measured using a pneumotachograph (PT). The generalization ability of the resulting two-hidden-layer ANN model was compared with a linear predictive model developed through partial least squares (PLS) regression, as well as other V(I) predictive models proposed in the literature. Using an independent dataset recorded from nine 80-min step tests, the results showed that the ANN-estimated V(I) was highly correlated (R(2) = 0.88) with V(I) measured by the PT, with a mean difference of approximately 0.9%. In contrast, the PLS and other regression-based models resulted in larger average errors ranging from 7 to 34%. In addition, the ANN model yielded estimates of cumulative total volume that were on average within 1% of reference PT measurements. Compared with established statistical methods, the proposed ANN model demonstrates the potential to provide improved prediction of respiratory ventilation in workplace applications for which the use of traditional laboratory-based instruments is not feasible. Further research should be conducted to investigate the performance of ANNs for different types of physical activity in larger and more varied worker populations.

Dextromethorphan in the treatment of early myoclonic encephalopathy evolving into migrating partial seizures in infancy.

Epileptic encephalopathy with suppression-burst in electroencephalography (EEG) can evolve into a few types of epileptic syndromes. We present here an unusual case of early myoclonic encephalopathy that evolved into migrating partial seizures in infancy. A female neonate initially had erratic myoclonus movements, hiccups, and a suppression-burst pattern in EEG that was compatible with early myoclonic encephalopathy. The seizures were controlled with dextromethorphan (20 mg/kg), and a suppression-burst pattern in EEG was reverted to relatively normal background activity. However, at 72 days of age, alternating focal tonic seizures, compatible with migrating partial seizures in infancy, were demonstrated by the 24-hour EEG recording. The seizures responded poorly to dextromethorphan. To our knowledge, this is the first reported case of early myoclonic encephalopathy evolving into migrating partial seizure in infancy. Whether it represents another age-dependent epilepsy evolution needs more clinical observation.

Clinical Manifestations of Pediatric Food Allergy: a Contemporary Review.

Food allergies (FAs) are an emerging health care issue, and a "second wave of the allergy epidemic" was named. There are extensive data that documented the prevalence rate as high as approximately 10%. FAs are immunological adverse reactions, including IgE-mediated mechanisms, cell-mediated mechanisms, or mixed IgE- and cell-mediated mechanisms. A diagnosis of FA is made by specific symptoms encounter with food, detailed past history, sensitization tests, and oral food challenges (OFCs) if necessary. The component-resolved diagnostics (CRD) test can distinguish true or cross-reaction. "Minimal elimination" from the results of CRD and OFC could avoid unnecessary food restriction. Strict food limitation is harsh and stressful on patients and their families. Children with FAs experience a higher rate of post-traumatic stress symptoms (PTSS) and bullying than others. In the last 20 years, oral immunotherapy (OIT), sublingual immunotherapy (SLIT), and epicutaneous immunotherapy (EPIT) are treatment strategies. OIT and EPIT are the most two encouraging treatments for FA. This review aims to introduce FAs in diverse clinical disorders, new perspectives, and their practical implications in diagnosing and treating FA.

The combined effects of nucleotide-binding domain-like receptor protein 3 polymorphisms and levels of blood lead on developmental delays in preschool children.

Nucleotide-binding domain-like receptors protein 3 (NLRP3) inflammasomes are associated with neuroinflammation and multiple NLRP3 genes regulate NLRP3 expression. Our study aimed to investigate the association of NLRP3 polymorphisms with developmental delay in preschool children. We also explored whether NLRP3 polymorphisms modified the effects of total urinary arsenic and blood cadmium and lead to developmental delays. A total of 178 children with developmental delays and 88 healthy children were analyzed for urinary arsenic concentrations and red blood cell lead and cadmium concentrations. We examined the genotypes of fifteen common single-nucleotide polymorphisms in NLRP3. We observed that levels of total urinary arsenic and blood lead were significantly associated with developmental delay. The NLRP3rs10754555 CG versus CC/GG, NLRP3rs12048215 AG versus AA/GG, and NLRP3rs12137901 TC/TT versus CC genotype showed a lower odds of developmental delay, with the odds ratio (OR) and 95% confidence interval (CI) = 0.38 (0.19-0.75), 0.52 (0.27-0.99), and 0.33 (0.12-0.90), respectively. Children with the NLRP3rs10754555 CC/GG genotype and high blood lead levels had a significant multiplicative interaction with developmental delay [OR (95% CI) = 9.74 (3.59-26.45)]. This study found evidence that suggested the joint effects of NLRP3rs10754555 CC/GG genotype and high blood lead levels on developmental delays.

Laboratory evaluation of a physiologic sampling pump (PSP).

Recently, physiologic sampling pumps (PSPs), which can adjust their sampling rates in proportion to wearers' minute ventilation (V[combining dot above](E)), have been proposed to better estimate exposure to airborne contaminants in the workplace. A laboratory evaluation was conducted to compare the performance of a new PSP with a traditional sampling pump (TSP) in an exposure chamber. Fifteen subjects (aged 19-36 years) performed two replicate sessions of step-tests for correlated and uncorrelated exposure scenarios on four separate days. When exposed to a scenario in which subject V[combining dot above](E) is highly correlated with m-xylene concentration over the sampling period (r = 0.93), the PSP-measured time-weighted average (TWA) concentrations are higher than TSP-measured concentrations (average ratio of PSP to TSP = 1.18). The ratio of PSP- and TSP-measured TWA concentrations for the uncorrelated scenario (r = 0.02) is closer to one, as expected, with an average value of 0.94. The test results of the linear mixed model further indicate that the performance of the PSP is unaffected by the anthropometric and physiological characteristics of the wearer. Potential differences in exposure estimates resulting from the use of the two instruments were examined in light of various schemes which can potentially occur in the field. With the capability of estimating the total volume of air inhaled over the sampling period with improved accuracy, PSPs show promise in reducing the inherent uncertainty in current risk assessment approaches that entail constant-flow (TSP) sampling approaches.

Correlation of troponin I with perinatal and neonatal outcomes in neonates with respiratory distress.

BACKGROUND: The specific aims of the present study were to evaluate the associations between cardiac troponin I (Tn I) and perinatal events and whether Tn I serves as a predictor to evaluate neonatal outcomes. METHODS: Tn I level was assessed in sick neonates with respiratory distress within 12 h after birth. Apgar scores, acidosis, ventilator or oxygen requirement, hospital days and placenta clues were recorded. A total of 80 sick neonates were enrolled (54 preterm and 26 full-term neonates) delivered at Shin-Kong Wu Ho-Su Memorial Hospital between July 2003 and December 2004. RESULTS: There was a significant negative correlation between Apgar scores at 1 min and 5 min (r=-0.383, P= 0.001; r=-0.500, P < 0.001), acidosis (r=-0.309, P= 0.006), base excess (r=-0.332, P= 0.003) and Tn I. The subjects were divided into two groups using the median level of 0.028 ng/mL as a cut-off. There were significantly fewer neonates with high Apgar score (>7 at 5 min; 27/40, 69.2% vs 38/40, 97.4%; P= 0.001) in the higher Tn I group (> or =0.028 ng/mL). Lower pH (7.4 +/- 0.10 vs 7.3 +/- 0.1, P= 0.011), lower base excess (-1.0 +/- 4.3 vs -4.4 +/- 5.1, P= 0.003) and less placental weight (548.8 +/- 195.36 g vs 396.56 +/- 154.30 g, P= 0.019) were also seen in the higher Tn I group. CONCLUSION: Tn I may play a role in the assessment of perinatal outcomes but is not a precise predictor of neonatal outcomes. Tn I level of 0.028 ng/mL is also suggested as a predictor of severity of perinatal outcomes in neonates with respiratory distress.

A novel physiologic sampling pump capable of rapid response to breathing.

The merits of using physiologic sampling pumps (PSPs) instead of using constant-flow sampling pumps, i.e., "traditional sampling pumps" (TSPs), are discussed. A novel PSP that overcomes shortcomings of previous PSP designs is presented. Calibrated valves are used to obviate pump inertia that has limited the system response and accuracy of prior work. Technologies that provide minute ventilation (V[combining dot above](E)) of subjects in real time may therefore be used to the limit of their own accuracies to sample inhalation exposures. Analysis of the design and data from a prototype are presented to show how air sampling can be modulated to follow breathing.