Protocol to measure validity and reliability of colorectal, breast, cervical and lung cancer screening questions from the 2021 National Health Interview Survey: Methodology and design

Previous studies demonstrate that self-reports of mammography screening for breast cancer and colonoscopy screening for colorectal cancer demonstrate concordance, based on adherence to screening guidelines, with electronic medical records (EMRs) in over 90% of those interviewed, as well as high sensitivity and specificity, and can be used for monitoring our Healthy People goals. However, for screening tests for cervical and lung cancers, and for various sub-populations, concordance between self-report and EMRs has been noticeably lower with poor sensitivity or specificity. This study aims to test the validity and reliability of lung, colorectal, cervical, and breast cancer screening questions from the 2021 and 2022 National Health Interview Survey (NHIS). We present the protocol for a study designed to measure the validity and reliability of the NHIS cancer screening questions compared to EMRs from four US-based healthcare systems. We planned a randomized trial of a phone- vs web-based survey with NHIS questions that were previously revised based on extensive cognitive interviewing. Our planned sample size will be 1576 validity interviews, and 1260 interviews randomly assigned at 1 or 3 months after the initial interview. We are enrolling people eligible for cancer screening based on age, sex, and smoking history per US Preventive Services Task Force recommendations. We will evaluate question validity using concordance, sensitivity, specificity, positive predictive value, negative predictive value, and report-to-records ratio. We further are randomizing participants to complete a second survey 1 vs 3 months later to assess question reliability. We suggest that typical measures of concordance may need to be reconsidered in evaluating cancer screening questions.

Investigating the effects of rurality on stress, subjective well-being, and weight-related outcomes

Purpose

Rates of obesity are significantly higher for those living in a rural versus urban setting. High levels of stress and low levels of subjective well-being (SWB) have been linked to poor weight-related behaviors and outcomes, but it is unclear if these relationships differ as a function of rurality. This study investigated the extent to which living in a rural versus urban county ("rurality") moderated associations between stress / subjective wellbeing (predictors) and diet quality, dietary intake of added sugars, physical activity, and BMI (outcomes).

Methods

Participants were recruited from urban (n = 355) and rural (n = 347) counties in Washington State and self-reported psychological, demographic, and food frequency questionnaires while physical activity behavior was measured objectively.

Findings

After controlling for relevant covariates, levels of stress were positively associated with added sugar intake for those living in the urban county while this relationship was non-significant for those residing in the rural county. Similarly, SWB was negatively associated with added sugar intake, but only for urban residents. County of residence was also found to moderate the relationship between SWB and BMI. Higher SWB was inversely associated with BMI for those living in the urban county while no relationship was observed for rural county residents.

Conclusions

These findings support the hypothesis that the relationships between stress / SWB and weight function differentially based on the rurality of the residing county. This work adds to the growing body of literature highlighting the role stress and SWB play in the rural obesity disparity.

The efficacy of hydrogel containing zinc oxide-loaded and minocycline serum albumin nanopartical in the treatment of peri-implantitis

BACKGROUND

We conducted this animal study to assess the efficacy of the novel hydrogel containing zinc oxide-loaded and minocycline serum albumin nanoparticals (Mino-ZnO@Alb NPs) on peri-implantitis in an experimental mouse model.

MATERIAL AND METHODS

Mino-ZnO@Alb NPs was prepared as previously reported. The peri-implantitis model was successfully established in rats, and the rats were divided into three groups randomly: Mino-ZnO@Alb NPs (Mino-ZnO) group, minocycline group, and untreated group. Four weeks later, clinical and radiographic assessments were performed to evaluate soft tissue inflammation and bone resorption level. Histologic analysis was performed to estimate the amount of remaining supporting bone tissue (SBT) around implants. ELISA tests were used to determine the concentration of inflammation factor interleukin-1-beta (IL-1β) and anti-inflammation factor tumor necrosis factor-alpha (TNF-α) around implants.

RESULTS

After one month, the Mino-ZnO group showed better results than the other two groups in regards to the results of bleeding on probing, probing pocket depth, bleeding index and gingival index. X-ray showed that SBT at mesial and distal sites around implants in the other two groups was significantly lower compared with that of Mino-ZnO group. The quantity of osteoclasts in peri-implant tissues of the Mino-ZnO group was less than that in the minocycline and untreated groups. IL-1β in the Mino-ZnO group was lower than that in the other two groups. TNF-α level was the opposite.

CONCLUSIONS

Mino-ZnO@Alb NPs can effectively treat peri-implantitis and promote soft tissue healing, and may act as a promising product.

Ethnic disparities in the prevalence of SARS-CoV-2 testing positivity comparing Hispanic and non-Hispanic populations

Context: The Hispanics make up the largest ethnic minority in the United States (US). Hispanics have lower all-cause mortality and many chronic disease morbidities, despite lower socioeconomic status (SES), and barriers to health care. Whether this phenomenon, termed as the "Hispanic Paradox", holds during an infectious disease pandemic, warrants investigation. Objective: To examine the ethnic disparities in COVID-19 infection among general patients tested using PCR and understand risk factors of viral positivity other than Hispanic ethnicity. Study Design: Observational study design using retrospective electronic medical records (EMR). Setting or Dataset: All patients analyzed were ≥ 18 years old with at least one diagnostic Coronavirus molecular test in a community healthcare system in Washington State. Sociodemographic characteristics (age, sex, and race/ethnicity), date of testing, viral positivity, reasons for testing, body mass index (BMI), key comorbidities, and health insurance status were extracted from the EMR. Derived variables included Hispanic or non-Hispanic, no insurance, age groups, and obesity. Population Studied: Our analytical focus was on adult Hispanics. The study included both females and males and investigated non-Hispanics. All data were from community healthcare clinical patients. Outcome Measures: Viral positivity of COVID-19 infection. Results: Of 108,973 patients, Hispanics had a much higher overall viral positivity (16.9%) than non-Hispanics (8.5%, p = 0.000). Symptomatic Hispanic patients had 40.7% positivity at the peak point, compared to 21.0% for symptomatic non-Hispanics. The ethnic disparity also existed for asymptomatic patients (6.6% vs. 3.2%, p = 0.000). Symptomatic male Hispanics showed 29.5% positivity, 9.5 times that of non-Hispanic asymptomatic females (3.1%). Multivariate analysis showed that older age, male sex (OR = 1.42, p = 0.000), being symptomatic (OR = 6.03, 95% CI: 5.31-6.85), having no insurance (OR = 1.34, p = 0.041), obesity (OR = 1.18, p = 0.002), and Hispanic ethnicity (OR = 1.45, 95% CI: 1.16-1.82) were associated with higher likelihood of viral positivity, whilst being White (OR = 0.68, p = 0.000), having cancer (OR = 0.69, p = 0.005) or COPD (OR = 0.69, p = 0.000) were associated with lower test positivity. Conclusion: We found ethnic and racial disparities in COVID-19 viral positivity rates. The diminishing Hispanic Paradox warrants further investigation into SES, cultural, and behavioral factors.

Gender Discrepancies in SARS-CoV-2 Pandemic Related Beliefs, Attitudes, and Practices

Objectives: International studies suggest that males may be less likely to adhere to SARS-CoV-2 transmission mitigation efforts than females. However, there is a paucity of research in this field in the United States. The primary aim of this study was to explore the relationship of binary gender identity (female/male) with beliefs, attitudes, and pandemic-related practices in the early stages of the pandemic.

Methods: This study is based on a cross-sectional, voluntary response survey. Patients who were tested for SARS-CoV-2 between March 5 and June 7, 2020 were invited to participate. All patients were tested within a large community healthcare system that serves patients through eight hospitals and hundreds of clinics across Washington State. Bivariate associations between gender and various demographics were tested using Chi-squared and Student's t-tests. We examined associations between gender and pandemic-related beliefs, attitudes, and practices using multivariable logistic regression, accounting for potential confounding factors.

Results: Females were more likely than males to agree that they (aOR = 1.51, 95% CI 1.14–2.00) or their families (aOR = 1.75, 95% CI 1.31–2.33) were threatened by SARS-CoV-2, or that their own behavior could impact transmission (aOR = 2.17, 95% CI 1.49–3.15). Similarly, females were more likely to agree that social distancing (aOR = 1.72, 95% CI 1.19–2.46), handwashing (aOR = 3.27, 95% CI 2.06–5.21), and masking (aOR = 1.41, 95% CI 1.02–1.94) were necessary to slow SARS-CoV-2 spread. Females were significantly less likely to visit outside of their social distancing circle (aOR = 0.62, 95% CI 0.47–0.81), but among those who did, practices of social distancing (aOR = 1.41, 95% CI 0.89–2.23), remaining outdoors (aOR = 0.89, 95% CI 0.56–1.40), and masking (aOR = 1.19, 95% CI 0.74–1.93) were comparable to males, while females practiced handwashing more than males (aOR = 2.11, 95% CI 1.33–3.34).

Conclusions: Our study suggests that gender disparate beliefs, attitudes, and practices existed in the early stages of the SARS-CoV-2 pandemic. Efforts should be tailored to encourage males to engage with mitigation efforts in ongoing pandemic-related public health campaigns.

Characterising percentage energy from ultra-processed foods by participant demographics, diet quality and diet cost: findings from the Seattle Obesity Study (SOS) III

Higher consumption of 'ultra-processed' (UP) foods has been linked to adverse health outcomes. The present paper aims to characterise percentage energy from UP foods by participant socio-economic status (SES), diet quality, self-reported food expenditure and energy-adjusted diet cost. Participants in the population-based Seattle Obesity Study III (n 755) conducted in WA in 2016-2017 completed socio-demographic and food expenditure surveys and the FFQ. Education and residential property values were measures of SES. Retail prices of FFQ component foods (n 378) were used to estimate individual-level diet cost. Healthy Eating Index (HEI-2015) and Nutrient Rich Food Index 9.3 (NRF9.3) were measures of diet quality. UP foods were identified following NOVA classification. Multivariable linear regressions were used to test associations between UP foods energy, socio-demographics, two estimates of food spending and diet quality measures. Higher percentage energy from UP foods was associated with higher energy density, lower HEI-2015 and NRF9.3 scores. The bottom decile of diet cost ($216·4/month) was associated with 67·5 % energy from UP foods; the top decile ($369·9/month) was associated with only 48·7 % energy from UP foods. Percentage energy from UP foods was inversely linked to lower food expenditures and diet cost. In multivariate analysis, percentage energy from UP foods was predicted by lower food expenditures, diet cost and education, adjusting for covariates. Percentage energy from UP foods was linked to lower food spending and lower SES. Efforts to reduce UP foods consumption, an increasingly common policy measure, need to take affordability, food expenditures and diet costs into account.

Maternal Marijuana Exposure and Birth Weight: An Observational Study Surrounding Recreational Marijuana Legalization

OBJECTIVE

This study aimed to study the relationship between prenatal marijuana and infant birth weight using natural cohorts established before, during and after the 20-month lapse between legalization and legal recreational sales in Washington State.

STUDY DESIGN

Over 5 years, 5,343 pregnant women with documented urine drug screen (UDS) results delivered at Tacoma General Hospital or Good Samaritan Hospital. Maternal medical data were extracted for three delivery cohorts established based on before (T1), during (T2), and after legalization (T3) of recreational marijuana and legalized availability. Univariate and multivariate models were created to study marijuana exposure on infants' birth weight.

RESULTS

Marijuana exposure increased the risk of low birth weight (LBW; odds ratio [OR] = 1.42, 95% confidence interval [CI]: 1.01-2.01). This was more pronounced in full-term babies (OR = 1.72, 95% CI: 1.10-2.69), and was independently associated with a higher risk for small for gestational age (SGA; OR = 1.51, 95% CI: 1.49-1.53). The associations between marijuana exposure and SGA were maintained in cohort-specific models (OR = 1.53, 95% CI: 1.01-2.32 for T2, and OR = 1.43, 95% CI: 1.01-2.02 for T3, respectively).

CONCLUSION

Marijuana exposure verified by UDS was associated with LBW and SGA. However, recreational marijuana legalization and availability did not have direct impact on newborns' risk of LBW or SGA.

Empiric evidence of ethnic disparities in coronavirus positivity in Washington State

OBJECTIVES

Early reports from the initial months of the coronavirus pandemic reveal ethnic disparities in coronavirus incidence, severity, and mortality. This study aimed to evaluate the relationship between ethnicity and outcomes of coronavirus positivity and hospitalization.

DESIGN

An observational cohort study using electronic health record (EHR) data from a large community healthcare system in Washington State across the first phase of the pandemic (March 5 - June 7, 2020).

RESULTS

A total of 18,667 patients (65.9% of all tested) with EHR-documented ethnicity were included. Overall, 6.4% of patients tested positive for coronavirus. Among Latinx patients, 18.6% of those tested were positive, compared to only 4.0% of tested White patients. Multivariable logistic regression revealed significantly higher odds of positivity for Latinxs (aOR = 4.96, 95% CI 4.19-5.87), Asians (aOR = 2.33, 95% CI 1.74-3.08), Blacks (aOR = 1.82, 95% CI 1.43-2.31), and members of other ethnic minority groups (aOR = 2.34, 95% CI 1.80-2.95), compared to Whites in models adjusting for relevant confounders. Latinxs had a higher percentage of self-pay insurance (22.2%) compared to other ethnic groups (7.9-15.8%) and, among those who tested positive, were the only ethnic subpopulation with significantly higher odds than Whites to be hospitalized for COVID-19 (aOR = 2.19, 95% CI 1.45-3.33). We observed a positive correlation between infection and the percentage of Latinxs (r = 0.61, 95% CI 0.45-0.74), Blacks (r = 0.51, 95% CI 0.32-0.66), or Asians (r = 0.64, 95% CI 0.49-0.76) in a given zip-code. This correlationwas negative for Whites (r = -0.63, 95% CI -0.75, -0.45).

CONCLUSIONS

We present empirical evidence of higher rates of coronavirus positivity among People of Color compared to White people in Washington State. Social determinants of health, such as occupation, housing, healthcare access, and community structure, may contribute to health disparities in the coronavirus pandemic. Targeted capture of these variables in electronic health records is warranted to inform health equity analyses.

A cross-sectional analysis of physical activity and weight misreporting in diverse populations: The Seattle Obesity Study III

BACKGROUND

In-person assessments of physical activity (PA) and body weight can be burdensome for participants and cost prohibitive for researchers. This study examined self-reported PA and weight accuracy and identified patterns of misreporting in a diverse sample.

METHODS

King, Pierce and Yakima county residents, aged 21-59 years (n = 728), self-reported their moderate-to-vigorous PA (MVPA) and weight, in kilograms. Self-reports were compared with minutes of bout-level MVPA, from 3 days of accelerometer data, and measured weights. Regression models examined characteristics associated with underreporting and overreporting of MVPA and weight, the potential bias introduced using each measure and the relation between perceived and measured PA and weight.

RESULTS

MVPA underreporting was higher among males and college educated participants; however, there was no differential MVPA overreporting. Weight underreporting was higher among males, those age 40-49 years and persons with obesity. Weight overreporting was higher among Hispanic participants and those reporting stress, unhappiness and fair or poor health. The estimated PA-obesity relation was similar using measured and self-reported PA but not self-reported weight. Perceived PA and weight predicted measured values.

CONCLUSION

Self-reported PA and weight may be useful should objective measurement be infeasible; however, though population-specific adjustment for differential reporting should be considered.

Demographic Discrepancies in Prenatal Urine Drug Screening in Washington State Surrounding Recreational Marijuana Legalization and Accessibility

OBJECTIVES

This study evaluated demographic patterns related to prenatal cannabinoid urine drug screening (UDS) over a 5-year period during which recreational marijuana was legalized and became accessible in Washington State.

METHODS

Using electronic health record data, we performed a retrospective analysis for deliveries occurring over a 5-year period that encapsulated the transitions to marijuana legalization and legal access. For three cohorts of women delivering prior to legalization, between legalization and accessibility, and following accessibility, the UDS completion rate and screening demographic characteristics were assessed using Chi-squared tests and multivariate logistic regression.

RESULTS

25,514 deliveries occurred between March 2011 and March 2016. A significantly higher percentage of women underwent UDS post-accessibility (24.5%) compared to pre-legalization (20.0%, p < 0.001). A corresponding increase was not observed in the percentage of marijuana-positive UDS in tested patients (22.7% vs. 23.3%, p = 0.86). African American women had 2.8 times higher odds than Latinas of being tested, 2.1 times higher odds than Asian women, 1.7 times higher odds than White women, and 1.4 times higher odds than women of other races (all p < 0.001). Subsidized insurance status was also strongly associated with increased likelihood of testing (aOR = 3.5, p < 0.001).

CONCLUSIONS FOR PRACTICE

Prenatal UDS testing patterns changed as recreational marijuana possession and accessibility became legal. Demographic discrepancies in testing reveal biases related to race and insurance status, which may be a proxy for socioeconomic status. As such discrepancies are potential contributors to health outcome disparities, it is important for providers and health care systems to examine their practices and ensure they are being appropriately, equally, and justly applied.

Small increments in diet cost can improve compliance with the Dietary Guidelines for Americans

Adherence to the Dietary Guidelines for Americans (DGA) may involve higher diet costs. This study assessed the relation between two measures of food spending and diet quality among adult participants (N = 768) in the Seattle Obesity Study (SOS III). All participants completed socio-demographic and food expenditure surveys and the Fred Hutch food frequency questionnaire. Dietary intakes were joined with local supermarket prices to estimate individual-level diet costs. Healthy Eating Index (HEI- 2015) scores measured compliance with DGA. Multiple linear regressions using Generalized Estimating Equations with robust standard errors showed that lower food spending was associated with younger age, Hispanic ethnicity, and lower socioeconomic status. Even though higher HEI-2015 scores were associated with higher diet costs per 2000 kcal, much individual variability was observed. A positive curvilinear relationship was observed in adjusted models. At lower cost diets, a $100/month increase in cost (from $150 to $250) was associated with a 20.6% increase in HEI-2015. For higher levels of diet cost (from $350 to $450) there were diminishing returns (2.8% increase in HEI- 2015). These findings indicate that increases in food spending at the lower end of the range have the most potential to improve diet quality.

1190 Engaging Patients And Family Members To Understand What Matters Most Living With Obstructive Sleep Apnea

Introduction

As a common but modifiable chronic condition, obstructive sleep apnea (OSA) has been identified as the top secondary cause of many other diseases including cardiovascular diseases and type 2 diabetes. Diagnosing and managing OSA provides neurological, cardiovascular and metabolic benefits, however real-world studies indicate disconnections between evidence and outcomes. Using an engagement approach and qualitative design, this project aims to better understand care and research gaps in OSA in a community healthcare setting.

Methods: Methods

Patient and family representatives were identified and recruited through OSA support meetings hosted by MultiCare Sleep Medicine Centers, to form a board of 12, with three key patient advocates. Six meetings, each facilitated by one or two members of the board, were held to encourage focus group discussion and accommodate interactive conversations on the topic. Discussions were audio recorded and edited to exclude patients’ identifiable information, then transcribed. Manual open coding was completed by two coders for each transcription to develop a codebook, followed by auto-coding and inductive content analysis using Nvivo 11.

Results

All enrolled patients had diagnosed moderate-to-severe OSA and were prescribed with continuous positive airway pressure (CPAP) therapy. Two participants were African American and one was multiethnic. Patients’ age ranged from early 30s to 80s. Seven main themes were identified: OSA diagnostic issues; treatment experiences and options; comorbidities; patient community and support needs; long-term management challenges beyond “compliance”; knowledge of OSA, CPAP and care; and patient-driven research. The first few weeks after CPAP initiation appeared to be a critical time window that impacted patients’ adaptation and use.

Conclusion

Our study revealed barriers and facilitators in OSA diagnosis and treatment. Results showed highly prevalent chronic co-morbidities and the needs to care for patients in the comorbid scenario. It was highlighted that a paradigm of patient-centered care and research is lacking and warranted. Participants also called for better coordination between sleep medicine, primary care, other specialists, durable device suppliers and insurance. Key research efforts are expected to focus on the first 30-day post CPAP dispense to improve compliance.

Support

Patient Centered Outcomes Research Institute (PCORI) (Contract #: 7717241)

Delay in Treatment After Cancer Diagnosis in Adolescents and Young Adults: Does Facility Transfer Matter?

Background: Timeliness is one of the fundamental yet understudied quality metrics of cancer care. Little is known about cancer treatment delay among adolescent and young adult (AYA) cancer patients. This study assessed cancer treatment delay, with a specific focus on facility transfer and diagnosis/treatment interval. Methods: Based on MultiCare Health System's (MHS's) institutional cancer registry data of AYA patients diagnosed during 2006-2015, this study analyzed patient demographics, insurance, clinical characteristics, and time of diagnosis and treatment initiation. Chi-squared tests, cumulative hazard estimates, and Cox proportional regression were used for univariable analysis. Multivariate regression models were used to test the association between care transfer and days of interval or prolonged delay, controlling for baseline parameters. Results: Of 840 analytic AYA cases identified, 457 (54.5%) were both diagnosed and treated within MHS. A total of 45.5% were either diagnosed or treated elsewhere. Mean and median intervals for treatment initiation were 27.03 (95% CI = 21.94-33.14) and 8.00 days (95% CI = 5.00-11.00), respectively, with significant differences between patients with and without facility transfer. Transfer was significantly correlated with longer length of diagnosis-to-treatment interval. Treatment delay, ≥1 week, was associated with transfer, female sex, older age, no surgery involvement, and more treatment modalities. Treatment delay, ≥4 weeks, was associated with transfer, female sex, no insurance, and no surgery involvement. Conclusion: In a community care setting, the diagnosis-to-treatment interval is significantly longer for transferred AYA cancer patients than for patients without a transfer. Future studies are warranted to explore the prognostic implications and the reasons for delays within specific cancer types.

The Optimal Surgical Approach Selection for Papillary Thyroid Carcinoma With Pathological N1 Metastases: An Analyses on SEER Database

Background: The definition of large-volume pathologic N1 metastases has been changed in the 2017 version of National Comprehensive Cancer Network (NCCN) guidelines, leading to a controversy over the optimal surgical approach selection for patients with papillary thyroid carcinoma (PTC). Aim: The aim of this study was to investigate the therapeutic efficacy of total thyroidectomy (TT) and thyroid lobectomy (TL) for these patients. Methods: In total 906 consecutive PTC patients with metastases ≤ 5 mm were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database, and divided into 2 groups (≤2 mm, >2 to 5 mm) based on the size of extend of disease (EOD). The overall survival (OS) was then compared between patients treated with TT and TL, followed by Cox-proportional hazards regression analysis to explore multiple prognostic factors. Results: OS favored TT compared with TL in patients with more than 5 involved nodes and metastases > 2 to 5 mm in largest dimension ( P < 0.05). Meanwhile, Cox analysis showed that the TL was not an independent factor associated with poorer OS than TT in these patients ( P > 0.05). TT showed better survival than TL for patients with metastases > 2 mm to 5 mm. For patients with metastases ≤ 2 mm, either TT or TL should be recommended because of no discrepancy in survival. Conclusion: TT does offer slight survival advantage over TL for PTC patients with metastases > 2 mm to 5 mm; TT may be recommended for these patients to improve disease-special survival and reduce the risk of recurrence.

Changing outpatient referral patterns in a small pediatric nephrology practice

Background

We have noted a large number of referrals for abnormal kidney imaging and laboratory tests and postulated that such referrals have increased significantly over time. Understanding changes in referral patterns is helpful in tailoring education and communication between specialists and primary providers.

Methods

We performed a retrospective chart review of new patient referrals to Mary Bridge Children’s Nephrology clinic for early (2002 to 2004) and late (2011 to 2013) cohorts. The overall and individual frequencies of referrals for various indications were compared.

Results

The overall number of new visits was similar for early (511) and late (509) cohorts. The frequency of referrals for solitary kidneys and multi-cystic dysplastic kidneys, microalbuminuria and abnormal laboratory results increased significantly (Odds Ratio (OR) and 95% Confidence Interval of OR: 1.920 [1.079, 3.390], 2.862 [1.023, 8.006], 2.006 [1.083, 3.716], respectively) over the time interval while the proportion of referrals for urinary tract infections (UTIs) and vesicoureteral reflux (VUR) decreased by half (OR: 0.472, 95% CI: 0.288, 0.633). Similarly, referrals for urinary tract dilation and hydronephrosis occurred significantly less often (8% versus 6%, OR: 0.737, 95% CI: 0.452, 1.204) with similar changes in referrals for voiding issues (OR: 0.281, 95% CI: 0.137, 0.575). However, these changes were not statistically significant. Frequencies for other indications showed little variation.

Conclusions

Changes in indications for referral likely reflect evolution of practice in management of UTIs and VUR and increased use of imaging and laboratory testing by pediatric providers. These findings have relevance for ongoing education of pediatricians and support the need for collaboration between primary providers and nephrologists to assure the judicious use of resources.

The discriminative power of STOP-Bang as a screening tool for suspected obstructive sleep apnea in clinically referred patients: considering gender differences

PURPOSE

Obstructive sleep apnea (OSA) is the most commonly seen clinical sleep disorder. STOP-Bang, a widely used screening tool, yields a composite score based on eight dichotomized items including male gender. This study was designed to validate STOP-Bang among clinically referred patients and tested alternative scoring designs on tool performance, with a focus on gender differences in OSA.

METHOD

STOP-Bang was administered to 403 female and 532 male subjects, followed by comprehensive sleep evaluation that included measurement of apnea-hypopnea indexes. Gender differences in STOP-Bang scores, OSA diagnosis, and severities were explored, and gender-specific alternative score cutoffs evaluated. Optimal operating points (OOP) were tested for female body mass index (BMI) and male neck circumference to inform STOP-Bang threshold refinement. Receiver operating characteristic curves were used to compare conventional and modified STOP-Bang.

RESULTS

STOP-Bang performance by gender showed extremely low specificity in males at the recommended cutoff of ≥3. Better utility was presented at a cutoff of 4 or 5 among clinically referred patients irrespective of gender differences. Screening performance was improved by modifying BMI and/or neck circumference thresholds using gender-triaged OOP estimation. Three gender-based model revisions outperformed conventional STOP-Bang.

CONCLUSION

Our study suggests that gender-specific consideration needs to be incorporated into the application of STOP-Bang in a clinically referred patient population with a higher risk of OSA. Alternative scoring systems may improve predictive performance of STOP-Bang.

Patient Satisfaction with Virtual Obstetric Care

Introduction The importance of patient satisfaction in US healthcare is increasing, in tandem with the advent of new patient care modalities, including virtual care. The purpose of this study was to compare the satisfaction of obstetric patients who received one-third of their antenatal visits in videoconference ("Virtual-care") compared to those who received 12-14 face-to-face visits in-clinic with their physician/midwife ("Traditional-care"). Methods We developed a four-domain satisfaction questionnaire; Virtual-care patients were asked additional questions about technology. Using a modified Dillman method, satisfaction surveys were sent to Virtual-care (N = 378) and Traditional-care (N = 795) patients who received obstetric services at our institution between January 2013 and June 2015. Chi-squared tests of association, t-tests, logistic regression, and ANOVA models were used to evaluate differences in satisfaction and self-reported demographics between respondents. Results Overall satisfaction was significantly higher in the Virtual-care cohort (4.76 ± 0.44 vs. 4.47 ± 0.59; p < .001). Parity ≥ 1 was the sole significant demographic variable impacting Virtual-care selection (OR = 2.4, 95% CI: 1.5-3.8; p < .001). Satisfaction of Virtual-care respondents was not significantly impacted by the incorporation of videoconferencing, Doppler, and blood pressure monitoring technology into their care. The questionnaire demonstrated high internal consistency as measured by domain-based correlations and Cronbach's alpha. Discussion Respondents from both models were highly satisfied with care, but those who had selected the Virtual-care model reported significantly higher mean satisfaction scores. The Virtual-care model was selected by significantly more women who already have children than those experiencing pregnancy for the first time. This model of care may be a reasonable alternative to traditional care.

Randomized, double-blind clinical trial comparing basal insulin peglispro and insulin glargine, in combination with prandial insulin lispro, in patients with type 1 diabetes: IMAGINE 3

AIMS

To compare the efficacy and safety of basal insulin peglispro (BIL), which has a flat pharmacokinetic and pharmacodynamic profile and a long duration of action, with insulin glargine (GL) in patients with type 1 diabetes.

MATERIALS AND METHODS

In this phase III, 52-week, blinded study, we randomized 1114 adults with type 1 diabetes in a 3 : 2 distribution to receive either BIL (n = 664) or GL (n = 450) at bedtime, with preprandial insulin lispro, using intensive insulin management. The primary objective was to compare glycated haemoglobin (HbA1c) in the groups at 52 weeks, with a non-inferiority margin of 0.4%.

RESULTS

At 52 weeks, mean (standard error) HbA1c was 7.38 (0.03)% with BIL and 7.61 (0.04)% with GL {difference -0.22% [95% confidence interval (CI) -0.32, -0.12]; p < 0.001}. At 52 weeks more BIL-treated patients reached HbA1c <7% (35% vs 26%; p < 0.001), the nocturnal hypoglycaemia rate was 47% lower (p < 0.001) and the total hypoglycaemia rate was 11% higher (p = 0.002) than in GL-treated patients, and there was no difference in severe hypoglycaemia rate. Patients receiving BIL lost weight, while those receiving GL gained weight [difference -1.8 kg (95% CI -2.3, -1.3); p < 0.001]. Treatment with BIL compared with GL at 52 weeks was associated with greater increases from baseline in levels of serum triglyceride [difference 0.19 mmol/l (95% CI 0.11, 0.26); p < 0.001] and alanine aminotransferase (ALT) levels [difference 6.5 IU/l (95% CI 4.1, 8.9), p < 0.001], and more frequent injection site reactions.

CONCLUSIONS

In patients with type 1 diabetes, treatment with BIL compared with GL for 52 weeks resulted in a lower HbA1c, more patients with HbA1c levels <7%, and reduced nocturnal hypoglycaemia, but more total hypoglycaemia and injection site reactions and higher triglyceride and ALT levels.

A randomized clinical trial comparing basal insulin peglispro and insulin glargine, in combination with prandial insulin lispro, in patients with type 1 diabetes: IMAGINE 1

AIMS

The primary objective was to demonstrate that basal insulin peglispro (BIL) was non-inferior compared with insulin glargine (GL) for haemoglobin A1c (HbA1c) at 26 weeks with a non-inferiority margin of 0.4%.

MATERIALS AND METHODS

IMAGINE 1 was a Phase 3, open-label, parallel-arm study conducted in nine countries. Adults with type 1 diabetes (n = 455) were randomized (2:1) to bedtime BIL or GL in combination with prandial insulin lispro for 78 weeks, with a primary endpoint of 26 weeks. An electronic diary facilitated data capture and insulin dosing calculations for intensive insulin management.

RESULTS

At 26 weeks, mean HbA1c was 7.06% ± 0.04% and 7.43% ± 0.06% for patients assigned to BIL (N = 295) and GL (N = 160), respectively (difference -0.37% [95% CI: -0.50 to -0.23], P < .001); more patients on BIL achieved HbA1c <7% (44.9% vs 27.5%, P < .001). Compared with GL, patients using BIL lost weight, with lower fasting serum glucose and between-day fasting blood glucose variability, and 36% less nocturnal hypoglycemia, 29% more total hypoglycemia and more severe hypoglycemia. Total and prandial insulin doses were lower with BIL; basal insulin doses were higher. Alanine aminotransferase increased with BIL, with more patients having elevations ≥3 × ULN. BIL treatment was associated with more frequent injection site reactions and an increase from baseline in serum triglycerides.

CONCLUSIONS

In patients with type 1 diabetes, treatment with BIL compared to GL for 26 weeks was associated with lower HbA1c, less nocturnal hypoglycemia, lower glucose variability and weight loss. Increases in total and severe hypoglycemia, triglycerides, aminotransferases and injection site reactions were also noted.

Risk Factors for Vibrio parahaemolyticus Infection in a Southern Coastal Region of China

OBJECTIVES

The objectives of the study were to identify dietary and medical risk factors for Vibrio parahaemolyticus (VP) infection in the coastal city Shenzhen in China.

METHODS

In April-October 2012, we conducted a case-control study in two hospitals in Shenzhen, China. Laboratory-confirmed VP cases (N = 83) were matched on age, sex, and other social factors to healthy controls (N = 249). Subjects were interviewed using a questionnaire on medical history; contact with seawater; clinical symptoms and outcome; travel history over the past week; and dietary history 3 days prior to onset. Laboratory tests were used to culture, serotype, and genotype VP strains. We used logistic regression to calculate the odds ratios for the association of VP infection with potential risk factors.

RESULTS

In multivariate analysis, VP infection was associated with having pre-existing chronic disease (adjusted odds ratio [aOR], 6.0; 95% confidence interval [CI], 1.5-23.7), eating undercooked seafood (aOR, 8.0; 95% CI, 1.3-50.4), eating undercooked meat (aOR, 29.1; 95% CI, 3.0-278.2), eating food from a street food vendor (aOR, 7.6; 95% CI, 3.3-17.6), and eating vegetable salad (aOR, 12.1; 95% CI, 5.2-28.2).

CONCLUSIONS

Eating raw (undercooked) seafood and meat is an important source of VP infection among the study population. Cross-contamination of VP in other food (e.g., vegetables and undercooked meat) likely plays a more important role. Intervention should be taken to lower the risks of cross-contamination with undercooked seafood/meat, especially targeted at people with low income, transient workers, and people with medical risk factors.

Vibrio parahaemolyticus, Southern Coastal Region of China, 2007-2012

We analyzed the prevalence and characteristics of Vibrio parahaemolyticus among patients with acute infectious diarrhea in the southern coastal region of China. V. parahaemolyticus was the leading cause of bacterial infectious diarrhea in this region during 2007–2012. Serotype O3:K6 strains were most common, followed by serotypes O4:K8 and O3:K29.

Defining migration and its health impact in China

The scale and rapid expansion of urbanization resulting from socio-economic transformation in China at the beginning of the 21st century has accelerated rural-urban migration. Public health concerns from this increasing internal population mobility are now receiving attention from researchers. The health problems from internal migration pose particular demands on healthcare systems and relate to its demographic characteristics, with many younger and older people being left behind in the rural countryside. A review of literature, census, policy reports, government documents and media was undertaken to look at the classification system and health characteristics of China's internal migrants. It suggests that public health bears the consequences of political and economic decisions made elsewhere in society.

Paradoxical immune reconstitution inflammatory syndrome associated with cryptococcal meningitis in China: a 5-year retrospective cohort study

We performed a retrospective cohort study of hospitalised cryptococcal meningitis (CM) patients at a single centre to evaluate the clinical epidemiological features of paradoxical cryptococcal-related immune reconstitution inflammatory syndrome (CM-IRIS) in a setting in China. A total of 154 AIDS patients with CM were involved, and 17.5% experienced IRIS at a median of 27 days after initiation of antiretroviral therapy (ART). Overall, 3 deaths were directly attributed to IRIS. The occurrences of CM-IRIS were independently associated with the pre-ART CD4+count, pre-C-reactive protein level, and the timing of ART initiation.

Comparison of perceived quality amongst migrant and local patients using primary health care delivered by community health centres in Shenzhen, China

Background

Providing good quality primary health care to all inhabitants is one of the Chinese Government’s health care objectives. However, information is scarce regarding the difference in quality of primary health care delivered to migrants and local residents respectively. This study aimed to compare patients’ perceptions of quality of primary health care between migrants and local patients, and their willingness to use and recommend primary health care to others.

Methods

A cross-sectional survey was conducted. 787 patients in total were chosen from four randomly drawn Community Health Centers (CHCs) for interviews.

Results

Local residents scored higher than migrants in terms of their satisfaction with types of drugs available (3.62 vs. 3.45, p = 0.035), attitude of health workers (4.41 vs. 4.14, p = 0.042) and waiting time (4.30 vs. 3.86, p < 0.001). Even though there was no significant difference in overall satisfaction between local residents and migrants (4.16 vs. 3.91, p = 0.159), migrants were more likely to utilize primary health care as the first choice for their usual health problems (94.1% vs. 87.1%, p = 0.032), while local residents were more inclined to recommend Traditional Chinese Medicine to others (65.6% vs. 56.6%, p = 0.026).

Conclusions

Quality of primary health care given to migrants is less satisfactory than to local residents in terms of attitude of health workers and waiting time. Our study suggests quality of care could be improved through extending opening hours of CHCs and strengthening professional ethics education. Considering CHCs as the first choice by migrants might be due to their health insurance scheme, while locals’ recommendations for traditional Chinese medicine were possibly because of cultural differences.

Health of China's rural-urban migrants and their families: a review of literature from 2000 to 2012

BACKGROUND

Socioeconomic transformation in China at the beginning of the twenty-first century has led to rapid urbanization and accelerated rural-urban migration. As a result, the concerns about public health problems triggered by increasing internal population mobility have been more widely studied in recent years.

SOURCES OF DATA

Published data in Chinese and English on health of migrants and their families in mainland China from 2000 to 2012.

AREAS OF AGREEMENT

The shifting patterns of disease distribution due to rural-urban migration, health equity and health reform strategies that cater for this specific yet substantial subpopulation are outstanding concerns. Infectious diseases, mental health, occupational health and women's health are emerging public health priorities related to migration.

AREAS OF CONTROVERSY

The high mobility and large numbers of Chinese rural-urban migrants pose challenges to research methods and the reliability of evidence gained.

GROWING POINTS

While the theme of working migrants is common in the literature, there have also been some studies of health of those left behind but who often remain unregistered. Migration within China is not a single entity and understanding the dynamics of new and emerging societies will need further study.

AREAS TIMELY FOR DEVELOPING RESEARCH

Social, economic, emotional, environmental and behavioural risk factors that impact on health of migrants and their families call for more attention from health policy-makers and researchers in contemporary China.

Tobacco smoking among migrant factory workers in Shenzhen, China

BACKGROUND

While several studies of smoking behaviors in rural-to-urban Chinese migrants exist, none to our knowledge have focused on factory workers, estimated to represent between 10% and 20% of China's total rural-to-urban migratory population. This paper assesses factors associated with smoking behavior among rural-to-urban migrant factory workers in Shenzhen, China.

METHODS

A cross-sectional survey of migrant workers from 44 randomly selected factories in Shenzhen, China. Participants were migrant factory workers aged 16-59 years and holding nonlocal household registration. The main outcome measures were demographic, migration-related, and behavioral factors associated with smoking status.

RESULTS

Four thousand and eighty-eight completed questionnaires were obtained (response rate 95.5%). Overall smoking prevalence (including occasional, daily, and heavy daily smoking) was 19.1%. The prevalence of daily smoking (including heavy daily smoking) was higher in men (27.3%) than women (0.7%). These rates are significantly lower than national smoking rates (59.5% in men, 3.7% in women) and rates found in a similar study. A high-risk group of men who smoke heavily and consume alcohol frequently was identified. Longer working hours and less rest were associated with higher rates of smoking. Frequent Internet use and lack of insurance were associated with lifetime smoking. Gender-adjusted models showed that poorer mental health and an accumulated working time in Shenzhen of 2-3 years increased female workers' likelihood of smoking.

CONCLUSIONS

Migrant factory workers in Shenzhen had lower rates of smoking than other population groups in China. The identification of risk factors for heavy smoking may help to effectively target health promotion interventions.

Public health services in Shenzhen: a case study

As one of the fastest growing cities in Pearl River Delta of southern China, Shenzhen accommodates a higher percentage and increasing number of internal migrants, mainly coming from the inland areas. The public health issues that challenge its local government include the special population structure, high incidence of infectious diseases, high prevalence of mental problems, rising chronic disease burdens, and maternal and children’s health issues, although progress has been made in the past years. The health authority of Shenzhen has realized that provision of high quality equitable public health services to its residents, including migrants is of high priority, and should be supported by innovations in the health insurance system and establishment of community-based primary care networks. Making changes within the national-level health reform framework and learning from international experiences are necessary and important.

Seroprevalence of rubella in female migrant factory workers in Shenzhen, China

BACKGROUND

Rubella remains a common disease in Mainland China and is a major cause of severe birth defects from Congenital Rubella Syndrome (CRS). Rubella-containing vaccines were not included in China's National Expanded Program of Immunization (NEPI) until December 2007. In Shenzhen, women of childbearing age make up a large percentage of its migrant factory worker population. Understanding their immunity to rubella is critical in furthering efforts towards rubella vaccination programs.

OBJECTIVES

To investigate the seronegativity of rubella antibodies and evaluate potential associates of rubella immunity among female migrant factory workers in Shenzhen, China.

SUBJECTS AND METHODS

Serum samples were collected from 518 female migrant workers, aged 18-55, working in 44 randomly selected factories in Shenzhen, China during May through June of 2009. Samples were tested for Rubella Immunoglobulin G (IgG) using a commercial Enzyme-linked immunosorbant assay kit. Self-reported vaccination histories and socio-demographic information were also collected.

RESULTS

Of 518 female workers, 402 (77.6%) were immune to rubella. Significant differences in seronegativity were dependent on region of origin, being without a job contract, age group, marital status and seronegativity of measles.

CONCLUSIONS

Seroprevalence of antibodies to rubella in Shenzhen, China amongst female migrant workers is too low to provide immunity in the population. Given the high numbers of women of childbearing age amongst Shenzhen migrant factory workers coming from many provinces across China, local health authorities in Shenzhen should consider combining new rubella immunization programs with existing measles immunization efforts in this population.

[A survey of Japanese encephalitis antibody migrant workers in Shenzhen 2009]

OBJECTIVE

To understand the immunological status of Japanese encephalitis (JE) antibodies amongst migrant workers and to provide epidemiological basis for public health strategies on JE prevention and control in Shenzhen.

METHODS

A multi-stage random sampling method was used, and 1003 migrant workers aged 18 to 60 from 44 factories were investigated and their serum specimens were collected. The enzyme-linked immunosorbent assay (ELISA) was used to detect JE antibodies qualitatively.

RESULTS

The gross IgG seroprevalence rate for JE was 20.2% (203/1003). Sex-specified seroprevalence was 21.2% (103/485) for male and 19.3% (100/518) for female, respectively (χ(2) = 579, P > 0.05). Age-specific seropositive rates were 22.6% (12/53) for those below 20 years old, 18.7% (120/642) for those between 20-years old, 26.0% (58/223) for those between 30-years old and 15.3% (13/85) for those on or above 40 years old (χ(2) = 7.96, P > 0.05). Proportions for self-reported positive immunization, non-immunization and unclear immunization history were 22.1% (30/136), 22.1% (51/231) and 19.2% (122/636), respectively (χ(2) = 501, P > 0.05). Seroprevalence by region of origins showed that workers from Guangdong province was the highest (30.5%, 50/164), followed by workers from Guangxi (29.7%, 22/74) whilst workers from Shan(3)xi (5.4%, 2/37) had the lowest rate. Seroprevalence rate for managers (29.0%, 31/107) was higher than that of technicians (7.1%, 1/14) (χ(2) = 21.78, P < 0.05). Serological positive rate of workers with university or above educational background was the highest (32.7%, 16/49), followed by that for individuals with college degree (10.3%, 10/97) (χ(2) = 13.02, P < 0.05).

CONCLUSION

No associations are detected between JE seroprevalence and age, or sex, or self-reported immunization histories amongst migrant labor workers in Shenzhen. However, correlations between JE serological positive rate and region of origins, occupation and educational attainment are found to be significant. The gross seroprevalence of JE antibodies suggests that the level of JE antibodies amongst Shenzhen migrant workers is low and the population immunity barrier has yet to be established. It is necessary to strengthen prevention and control strategies of JE among labor workers of Shenzhen.

Health care utilisation amongst Shenzhen migrant workers: does being insured make a difference?

BACKGROUND

As one of the most populous metropolitan areas in the Pearl River Delta of South China, Shenzhen attracts millions of migrant workers annually. The objectives of this study were to compare health needs, self-reported health and healthcare utilisation of insured and uninsured migrant workers in Shenzhen, China, where a new health insurance scheme targeting at migrant workers was initiated.

METHODS

A cross-sectional survey using multi-staged sampling was conducted to collect data from migrant factory workers. Statistical tests included logistic regression analysis were used.

RESULTS

Among 4634 subjects (96.54%) who responded to the survey, 55.11% were uninsured. Disease patterns were similar irrespective of insurance status. The uninsured were more likely to be female, single, younger and less educated unskilled labourers with a lower monthly income compared with the insured. Out of 1136 who reported illness in the previous two weeks, 62.15% did not visit a doctor. Of the 296 who were referred for inpatient care, 48.65% did not attend because of inability to pay. Amongst those who reported sickness, 548 were insured and 588 were uninsured. Those that were insured, and had easier access to care were more likely to make doctor visits than those who were uninsured.

CONCLUSION

Health care utilisation patterns differ between insured and uninsured workers and insurance status appears to be a significant factor. The health insurance system is inequitably distributed amongst migrant workers. Younger less educated women who are paid less are more likely to be uninsured and therefore to pay out of pocket for their care. For greater equity this group need to be included in the insurance schemes as they develop.

Hepatitis E virus infection among domestic animals in eastern China

Hepatitis E virus (HEV) is a zoonotic pathogen of which several species of animal were reported as reservoirs. Antibodies to HEV and HEV RNA have been detected in some Chinese population and swine groups but few other domestic animals. In this study, to investigate the HEV prevalence, we tested sera from 788 pigs, 100 cows, 50 goats, 49 horses, 101 pet dogs, 105 chickens, 47 duck and 45 pigeons in eastern China for anti-HEV immunoglobulin G (IgG). We also tested 50% of the swine sera, all of sera from the other domestic animals and 13 Shanghai human sera which were positive for anti-HEV immunoglobulin M (IgM) for HEV RNA using reverse transcriptase-polymerase chain reaction. Our results indicated that 82.5% (222/269) of the sows, 53.9% (104/193) of the 4- to 6-month-old swine, 63.4% (168/265) of the 1- to 3-month-old swine, 55.7% (34/61) of the slaughterhouse swine, 24% (12/50) of the goats, 16.3% (8/49) of the horses, 17.8% (21/101) of the pet dogs, 6% (6/100) of the cows, 12.8% (6/47) of the ducks, 4.4% (2/45) of the pigeons and 1.9% (2/105) of the chickens exhibited positive for anti-HEV IgG. Inhibition assay confirmed the infection with HEV or HEV-like viruses in these domestic animals except pigeons and chickens. From the sera, we isolated 18 swine HEV strains, one horse HEV strain and two human HEV strains. Sequence analysis showed that the horse HEV isolate and one swine isolate belonged to genotype 3. The other isolates belonged to genotype 4. The two human isolates were phylogenetically closely related to eight of the swine isolates. In short, the presence of anti-HEV antibody had been confirmed in several species of domestic animals in eastern China and HEV RNA has been identified in swine, human and horse. This suggested that the authorities should pay more attention to the prevalence of HEV in eastern China.

[A case of human highly pathogenic avian influenza in Shenzhen, China: application of field epidemiological study]

OBJECTIVE

Based on analyzing the characteristics of a case with human avian influenza and the effects of field epidemiological study.

METHODS

An emergency-response-system was started up to follow the probable human Highly Pathogenic Avian Influenza case initially detected by the "Undefined Pneumonia Surveillance System of Shenzhen". Public health professionals administered several epidemiologic investigations and giving all the contacts of the patient with a 7-day-long medical observation for temporally related influenza-like illness. Reverse transcriptase-polymerase chain reaction (RT-PCR) with primers for H5 and N1 was applied to test respiratory tract samples and/or throat swabs of the patient and all his contacts specific for the hemagglutinin gene of influenza A H5N1. Activities and strategies such as media response,notification in the public, communications with multiple related sectors, social participation and information exchange with Hong Kong were involved in field control and management.

RESULTS

The patient was a male, 31 years old,with an occupation as a truck driver in a factory,and had been residing in Shenzhen for 7 years. Started with an influenza-like syndrome, the patient received treatment on the 4th day of the onset, from a clinic and on the 6th day from a regular hospital. On the 8th day of the disease course, he was confirmed by Shenzhen Center for Disease Control and Prevention as human avian flu case and was then transferred to Intensive Care Unit (ICU). On the 83rd day of commence, the patients was healed and released from the hospital. The patient had no significant exposure to sick poultry or poultry that died from the illness before the onset of the disease. The patient and five family members lived together, but no family member was affected and no contact showed positive results for H5N1. A small food market with live poultry, which was under formal supervision and before illness the patient once visited, located near his apartment. Totally, 35 swabs from live birds and bird's coops in the market for H5 nucleic acid were tested and all were negative. The influenza H5N1 virus isolated for the case was named as A/Guangdong/02/2006 (H5N1) or GD/2/06. Phylogenetic relationships and molecular characterization analysis revealed that all the segments of the H5N1 virus named GD/2/06 still belonged to avian segments. Investigation process and control measures were released to the general public through the media. Soon after the laboratory confirmation, information was released to the society, as well as Hong Kong Center for Health Protection. Local Departments of Agriculture, Industries & Business, and Entry-Exit Inspection & Quarantine Bureau together with the Public Health Department put up combined actions. A computer-based telephone survey was initiated to investigate attitudes and knowledge of residents in town, revealing that positive atmosphere dominated and no panic existed.

CONCLUSION

Rapid laboratory diagnosis of the virus was the key for successful treatment and survival result of the case. Still, the pathogen was from birds resources. No human-to-human transmission was observed, however, source of infection was unclear. Field epidemiological study could offer special methods for the responses of emergency public health problems.

[Determination of pentachlorophenol residues in textiles and leather and leather products by gas chromatography/mass spectrometry]

A method for determination of pentachlorophenol residues in textiles and leather and leather products by gas chromatography/mass spectrometry was developed. The pentachlorophenol residues in samples was acidified with sulphuric acid solution (6 mol/L) and extracted with n-hexane. After the n-hexane layer was washed with sodium sulphate solution (20 g/L)until it was clear, determination was made by means of a gas chromatograph equipped with MSD, using external standard method. A DB-17 fused silica capillary column (30 m x 0.25 mm i.d.; 0.25 micron film thickness) was employed in the analysis, The column temperature program included a 2 min isothermal period at 50 degrees C, temperature increased at a rate of 30 degrees C/min to 220 degrees C, and hold for 1 min; temperature increased of at a rate 6 degrees C/min to 260 degrees C, and hold for 1 min. Mass spectra were obtained by electron impact at 70 eV and the determination was made by means of SIM mode, selected monitoring ion (m/z) was 264 amu. The detection limit was 0.02 mg/kg. The average recovery was from 86.7% to 93.1% and CV (n = 10) is from 4.1% to 5.9%. This method was already used to determine the mass concentration of pentachlorophenol residues in raw cotton, towel, shirt, leather gloves, leather watchguard. The method is simple, rapid and accurate.

Chaperonins GroEL and GroES: views from atomic force microscopy

The Escherichia coli chaperonins, GroEL and GroES, as well as their complexes in the presence of a nonhydrolyzable nucleotide AMP-PNP, have been imaged with the atomic force microscope (AFM). We demonstrate that both GroEL and GroES that have been adsorbed to a mica surface can be resolved directly by the AFM in aqueous solution at room temperature. However, with glutaraldehyde fixation of already adsorbed molecules, the resolution of both GroEL and GroES was further improved, as all seven subunits were well resolved without any image processing. We also found that chemical fixation was necessary for the contact mode AFM to image GroEL/ES complexes, and in the AFM images. GroEL with GroES bound can be clearly distinguished from those without. The GroEL/ES complex was about 5 nm higher than GroEL alone, indicating a 2 nm upward movement of the apical domains of GroEL. Using a slightly larger probe force, unfixed GroEL could be dissected: the upper heptamer was removed to expose the contact surface of the two heptamers. These results clearly demonstrate the usefulness of cross-linking agents for the determination of molecular structures with the AFM. They also pave the way for using the AFM to study the structural basis for the function of GroE system and other molecular chaperones.

The effect of deformation on the lateral resolution of atomic force microscopy

A computer model based on the elastic properties of rubber is introduced for the evaluation of the lateral resolution in atomic force microscopy of deformable specimens. The computational results show that, if the full width at half-height can be defined as the lateral resolution, it is continuously improved at greater probe forces, at the expense of a reduced molecular height, In fact, even for a probe that is bigger than the molecule, the real size of the molecule can be 'recovered' at about 25% compression. This result demonstrates that for a better lateral resolution, a greater probe force can be beneficial, provided that the molecule is not moved or damaged and the response remains elastic. Measurements on isolated low-density lipoproteins (LDL) show that with 26% vertical compression, the lateral size measured in atomic force microscopy is only 72% of the value predicted by a simple convolution, and is only slightly larger (approximately 13%) than the known size of LDL. Therefore, the results on LDL provide a direct support for the conclusions of the computational model.

Gramicidin A aggregation in supported gel state phosphatidylcholine bilayers

Using an atomic force microscope, supported bilayers of saturated phosphatidylcholine (in the gel state) containing various amounts of gramicidin A (gA) were imaged in aqueous solutions and at room temperature. gA clusters were directly observed for the first time under these conditions. It was found that, at a lower gA concentration, gA aggregated into domains, composed of small clusters along with a considerable amount of lipids. This basic aggregation unit, most likely a hexamer, remained the same for acyl chain lengths from 14 to 18 carbons. These small clusters were observed to form elongated aggregates (line type) but never into extended pure gA domains. When gA concentrations were increased, for bilayers with 16 carbons or less, gA aggregated into larger domains but the basic unit remained separated by lipid molecules. At about 5 mol % gA, a percolation-like transition occurred at which the line type aggregates were connected to each other. However, for bilayers with more than 16 carbons, multiple lamellar structures were formed at higher gA fractions and the top layer had a ripple-like surface morphology. The molecular mechanism for the formation of these peculiar structures remains to be elucidated.