Genomic surveillance reveals dynamic shifts in the connectivity of COVID-19 epidemics

The maturation of genomic surveillance in the past decade has enabled tracking of the emergence and spread of epidemics at an unprecedented level. During the COVID-19 pandemic, for example, genomic data revealed that local epidemics varied considerably in the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage importation and persistence, likely due to a combination of COVID-19 restrictions and changing connectivity. Here, we show that local COVID-19 epidemics are driven by regional transmission, including across international boundaries, but can become increasingly connected to distant locations following the relaxation of public health interventions. By integrating genomic, mobility, and epidemiological data, we find abundant transmission occurring between both adjacent and distant locations, supported by dynamic mobility patterns. We find that changing connectivity significantly influences local COVID-19 incidence. Our findings demonstrate a complex meaning of "local" when investigating connected epidemics and emphasize the importance of collaborative interventions for pandemic prevention and mitigation.

Implementation of Practical Surface SARS-CoV-2 Surveillance in School Settings

Surface sampling for SARS-CoV-2 RNA detection has shown considerable promise to detect exposure of built environments to infected individuals shedding virus who would not otherwise be detected. Here, we compare two popular sampling media (VTM and SDS) and two popular workflows (Thermo and PerkinElmer) for implementation of a surface sampling program suitable for environmental monitoring in public schools. We find that the SDS/Thermo pipeline shows superior sensitivity and specificity, but that the VTM/PerkinElmer pipeline is still sufficient to support surface surveillance in any indoor setting with stable cohorts of occupants (e.g., schools, prisons, group homes, etc.) and may be used to leverage existing investments in infrastructure. IMPORTANCE The ongoing COVID-19 pandemic has claimed the lives of over 5 million people worldwide. Due to high density occupancy of indoor spaces for prolonged periods of time, schools are often of concern for transmission, leading to widespread school closings to combat pandemic spread when cases rise. Since pediatric clinical testing is expensive and difficult from a consent perspective, we have deployed surface sampling in SASEA (Safer at School Early Alert), which allows for detection of SARS-CoV-2 from surfaces within a classroom. In this previous work, we developed a high-throughput method which requires robotic automation and specific reagents that are often not available for public health laboratories such as the San Diego County Public Health Laboratory (SDPHL). Therefore, we benchmarked our method (Thermo pipeline) against SDPHL's (PerkinElmer) more widely used method for the detection and prediction of SARS-CoV-2 exposure. While our method shows superior sensitivity (false-negative rate of 9% versus 27% for SDPHL), the SDPHL pipeline is sufficient to support surface surveillance in indoor settings. These findings are important since they show that existing investments in infrastructure can be leveraged to slow the spread of SARS-CoV-2 not in just the classroom but also in prisons, nursing homes, and other high-risk, indoor settings.

Sentinel Cards Provide Practical SARS-CoV-2 Monitoring in School Settings

A promising approach to help students safely return to in person learning is through the application of sentinel cards for accurate high resolution environmental monitoring of SARS-CoV-2 traces indoors. Because SARS-CoV-2 RNA can persist for up to a week on several indoor surface materials, there is a need for increased temporal resolution to determine whether consecutive surface positives arise from new infection events or continue to report past events. Cleaning sentinel cards after sampling would provide the needed resolution but might interfere with assay performance. We tested the effect of three cleaning solutions (BZK wipes, Wet Wipes, RNase Away) at three different viral loads: "high" (4 × 104 GE/mL), "medium" (1 × 104 GE/mL), and "low" (2.5 × 103 GE/mL). RNase Away, chosen as a positive control, was the most effective cleaning solution on all three viral loads. Wet Wipes were found to be more effective than BZK wipes in the medium viral load condition. The low viral load condition was easily reset with all three cleaning solutions. These findings will enable temporal SARS-CoV-2 monitoring in indoor environments where transmission risk of the virus is high and the need to avoid individual-level sampling for privacy or compliance reasons exists. IMPORTANCE Because SARS-CoV-2, the virus that causes COVID-19, persists on surfaces, testing swabs taken from surfaces is useful as a monitoring tool. This approach is especially valuable in school settings, where there are cost and privacy concerns that are eliminated by taking a single sample from a classroom. However, the virus persists for days to weeks on surface samples, so it is impossible to tell whether positive detection events on consecutive days are a persistent signal or new infectious cases and therefore whether the positive individuals have been successfully removed from the classroom. We compare several methods for cleaning "sentinel cards" to show that this approach can be used to identify new SARS-CoV-2 signals day to day. The results are important for determining how to monitor classrooms and other indoor environments for SARS-CoV-2 virus.

Wastewater sequencing reveals early cryptic SARS-CoV-2 variant transmission

As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing and/or sequencing capacity, which can also introduce biases^1–3. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing^4,5. Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We developed and deployed improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detected emerging variants of concern up to 14 days earlier in wastewater samples, and identified multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.

Emerging SARS-CoV-2 variants of concern were detected early and multiple cases of virus spread not captured by clinical genomic surveillance were identified using high-resolution wastewater and clinical sequencing.

SARS-CoV-2 Distribution in Residential Housing Suggests Contact Deposition and Correlates with Rothia sp

Monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on surfaces is emerging as an important tool for identifying past exposure to individuals shedding viral RNA. Our past work demonstrated that SARS-CoV-2 reverse transcription-quantitative PCR (RT-qPCR) signals from surfaces can identify when infected individuals have touched surfaces and when they have been present in hospital rooms or schools. However, the sensitivity and specificity of surface sampling as a method for detecting the presence of a SARS-CoV-2 positive individual, as well as guidance about where to sample, has not been established. To address these questions and to test whether our past observations linking SARS-CoV-2 abundance to Rothia sp. in hospitals also hold in a residential setting, we performed a detailed spatial sampling of three isolation housing units, assessing each sample for SARS-CoV-2 abundance by RT-qPCR, linking the results to 16S rRNA gene amplicon sequences (to assess the bacterial community at each location), and to the Cq value of the contemporaneous clinical test. Our results showed that the highest SARS-CoV-2 load in this setting is on touched surfaces, such as light switches and faucets, but a detectable signal was present in many untouched surfaces (e.g., floors) that may be more relevant in settings, such as schools where mask-wearing is enforced. As in past studies, the bacterial community predicts which samples are positive for SARS-CoV-2, with Rothia sp. showing a positive association. IMPORTANCE Surface sampling for detecting SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is increasingly being used to locate infected individuals. We tested which indoor surfaces had high versus low viral loads by collecting 381 samples from three residential units where infected individuals resided, and interpreted the results in terms of whether SARS-CoV-2 was likely transmitted directly (e.g., touching a light switch) or indirectly (e.g., by droplets or aerosols settling). We found the highest loads where the subject touched the surface directly, although enough virus was detected on indirectly contacted surfaces to make such locations useful for sampling (e.g., in schools, where students did not touch the light switches and also wore masks such that they had no opportunity to touch their face and then the object). We also documented links between the bacteria present in a sample and the SARS-CoV-2 virus, consistent with earlier studies.

Wastewater sequencing uncovers early, cryptic SARS-CoV-2 variant transmission

As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing/sequencing capacity, which can also introduce biases. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing. Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here, we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We develop and deploy improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detect emerging variants of concern up to 14 days earlier in wastewater samples, and identify multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.

Wastewater sequencing uncovers early, cryptic SARS-CoV-2 variant transmission

As SARS-CoV-2 continues to spread and evolve, detecting emerging variants early is critical for public health interventions. Inferring lineage prevalence by clinical testing is infeasible at scale, especially in areas with limited resources, participation, or testing/sequencing capacity, which can also introduce biases. SARS-CoV-2 RNA concentration in wastewater successfully tracks regional infection dynamics and provides less biased abundance estimates than clinical testing. Tracking virus genomic sequences in wastewater would improve community prevalence estimates and detect emerging variants. However, two factors limit wastewater-based genomic surveillance: low-quality sequence data and inability to estimate relative lineage abundance in mixed samples. Here, we resolve these critical issues to perform a high-resolution, 295-day wastewater and clinical sequencing effort, in the controlled environment of a large university campus and the broader context of the surrounding county. We develop and deploy improved virus concentration protocols and deconvolution software that fully resolve multiple virus strains from wastewater. We detect emerging variants of concern up to 14 days earlier in wastewater samples, and identify multiple instances of virus spread not captured by clinical genomic surveillance. Our study provides a scalable solution for wastewater genomic surveillance that allows early detection of SARS-CoV-2 variants and identification of cryptic transmission.

SARS-CoV-2 Distribution in Residential Housing Suggests Contact Deposition and Correlates with Rothia sp

Monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on surfaces is emerging as an important tool for identifying past exposure to individuals shedding viral RNA. Our past work has demonstrated that SARS-CoV-2 reverse transcription-quantitative PCR (RT-qPCR) signals from surfaces can identify when infected individuals have touched surfaces such as Halloween candy, and when they have been present in hospital rooms or schools. However, the sensitivity and specificity of surface sampling as a method for detecting the presence of a SARS-CoV-2 positive individual, as well as guidance about where to sample, has not been established. To address these questions, and to test whether our past observations linking SARS-CoV-2 abundance to Rothia spp. in hospitals also hold in a residential setting, we performed detailed spatial sampling of three isolation housing units, assessing each sample for SARS-CoV-2 abundance by RT-qPCR, linking the results to 16S rRNA gene amplicon sequences to assess the bacterial community at each location and to the Cq value of the contemporaneous clinical test. Our results show that the highest SARS-CoV-2 load in this setting is on touched surfaces such as light switches and faucets, but detectable signal is present in many non-touched surfaces that may be more relevant in settings such as schools where mask wearing is enforced. As in past studies, the bacterial community predicts which samples are positive for SARS-CoV-2, with Rothia sp. showing a positive association.

IMPORTANCE

Surface sampling for detecting SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is increasingly being used to locate infected individuals. We tested which indoor surfaces had high versus low viral loads by collecting 381 samples from three residential units where infected individuals resided, and interpreted the results in terms of whether SARS-CoV-2 was likely transmitted directly (e.g. touching a light switch) or indirectly (e.g. by droplets or aerosols settling). We found highest loads where the subject touched the surface directly, although enough virus was detected on indirectly contacted surfaces to make such locations useful for sampling (e.g. in schools, where students do not touch the light switches and also wear masks so they have no opportunity to touch their face and then the object). We also documented links between the bacteria present in a sample and the SARS-CoV-2 virus, consistent with earlier studies.

SARS-CoV-2 Distribution in Residential Housing Suggests Contact Deposition and Correlates with Rothia sp

Monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on surfaces is emerging as an important tool for identifying past exposure to individuals shedding viral RNA. Our past work has demonstrated that SARS-CoV-2 reverse transcription-quantitative PCR (RT-qPCR) signals from surfaces can identify when infected individuals have touched surfaces such as Halloween candy, and when they have been present in hospital rooms or schools. However, the sensitivity and specificity of surface sampling as a method for detecting the presence of a SARS-CoV-2 positive individual, as well as guidance about where to sample, has not been established. To address these questions, and to test whether our past observations linking SARS-CoV-2 abundance to Rothia spp. in hospitals also hold in a residential setting, we performed detailed spatial sampling of three isolation housing units, assessing each sample for SARS-CoV-2 abundance by RT-qPCR, linking the results to 16S rRNA gene amplicon sequences to assess the bacterial community at each location and to the Cq value of the contemporaneous clinical test. Our results show that the highest SARS-CoV-2 load in this setting is on touched surfaces such as light switches and faucets, but detectable signal is present in many non-touched surfaces that may be more relevant in settings such as schools where mask wearing is enforced. As in past studies, the bacterial community predicts which samples are positive for SARS-CoV-2, with Rothia sp. showing a positive association.

IMPORTANCE

Surface sampling for detecting SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is increasingly being used to locate infected individuals. We tested which indoor surfaces had high versus low viral loads by collecting 381 samples from three residential units where infected individuals resided, and interpreted the results in terms of whether SARS-CoV-2 was likely transmitted directly (e.g. touching a light switch) or indirectly (e.g. by droplets or aerosols settling). We found highest loads where the subject touched the surface directly, although enough virus was detected on indirectly contacted surfaces to make such locations useful for sampling (e.g. in schools, where students do not touch the light switches and also wear masks so they have no opportunity to touch their face and then the object). We also documented links between the bacteria present in a sample and the SARS-CoV-2 virus, consistent with earlier studies.

Comparison of heat-inactivated and infectious SARS-CoV-2 across indoor surface materials shows comparable RT-qPCR viral signal intensity and persistence

Environmental monitoring in public spaces can be used to identify surfaces contaminated by persons with COVID-19 and inform appropriate infection mitigation responses. Research groups have reported detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) on surfaces days or weeks after the virus has been deposited, making it difficult to estimate when an infected individual may have shed virus onto a SARS-CoV-2 positive surface, which in turn complicates the process of establishing effective quarantine measures. In this study, we determined that reverse transcription-quantitative polymerase chain reaction (RT-qPCR) detection of viral RNA from heat-inactivated particles experiences minimal decay over seven days of monitoring on eight out of nine surfaces tested. The properties of the studied surfaces result in RT-qPCR signatures that can be segregated into two material categories, rough and smooth, where smooth surfaces have a lower limit of detection. RT-qPCR signal intensity (average quantification cycle (Cq)) can be correlated to surface viral load using only one linear regression model per material category. The same experiment was performed with infectious viral particles on one surface from each category, with essentially identical results. The stability of RT-qPCR viral signal demonstrates the need to clean monitored surfaces after sampling to establish temporal resolution. Additionally, these findings can be used to minimize the number of materials and time points tested and allow for the use of heat-inactivated viral particles when optimizing environmental monitoring methods.

Using mobile multimedia platforms in teaching dental diagnosis

OBJECTIVE

Mobile Multimedia Platforms (MMPs) are prolific tools that can be used by individuals and corporations to share content. However, few studies have shown the effectiveness of MMPs as educational tools. Through this study, we aimed to evaluate the effectiveness of MMPs in improving basic dental diagnostic skills. In addition, we captured student feedback on the use of MMPs in a dental curriculum.

METHOD

In this voluntary interventional study on 89 senior dental students, we created pilot learning modules through an MMP called Instagram Stories to teach dental diagnosis. We evaluated the efficacy of the modules through diagnostic tests that were given to dental students who were close to graduating.

RESULTS

The students showed a significant increase in diagnostic test scores from 49% to 73% (p < 0.05) after the use of an MMP. Furthermore, the students' feedback on the MMP indicated that most students found it easy and enjoyable to use.

CONCLUSION

Our study data show that MMPs may be used to improve training in basic dental diagnostic skills and can serve as an adjunct teaching tool. Moreover, MMP modules can potentially enrich professional education in developing countries where access to educational resources is limited.

Availability of and Participation in Workplace Health Promotion Programs by Sociodemographic, Occupation, and Work Organization Characteristics in US Workers

PURPOSE

To examine how the availability of and participation in workplace health promotion programs (WHPPs) vary as a function of sociodemographic, occupation, and work organization characteristics.

DESIGN

Cross-sectional study.

SETTING

2015 National Health Interview Survey and Occupational Health Supplement.

PARTICIPANTS

The study sample included 17 469 employed adults who completed the WHPP questions.

MEASURES

The 2 dependent outcome measures were availability of WHPPs and participation in these programs when available. Independent variables included occupation and 8 work organization and employment characteristics: company size, hours worked, supervisory responsibility, hourly pay, paid sick leave, health insurance offered by employer, work schedule, and work arrangement.

ANALYSIS

Poisson regression analyses were conducted with SUDAAN 11.0.1.

RESULTS

Overall, 57.8% of 46.6% employees who have WHPPs available reported participating in these programs. This study found that adults who worked ≤20 h/wk, worked regular night shifts, were paid by the hour, or worked for temporary agencies were less likely to participate in WHPPs. Workers who supervised others were 13% more likely to participate than nonsupervisors. Borderline associations were seen for having access to employer-sponsored health insurance and working at a site with <10 employees.

CONCLUSION

Despite the potential for improving physical and mental health, only 58% of US workers participated in WHPPs. Since barriers to WHPP participation (eg, time constraints, lack of awareness, and no perceived need) may vary across occupations and work organization characteristics, employers should tailor WHPPs based on their specific work organization characteristics to maximize participation.

Type II Restriction of Bacteriophage DNA With 5hmdU-Derived Base Modifications

To counteract bacterial defense systems, bacteriophages (phages) make extensive base modifications (substitutions) to block endonuclease restriction. Here we evaluated Type II restriction of three thymidine (T or 5-methyldeoxyuridine, 5mdU) modified phage genomes: Pseudomonas phage M6 with 5-(2-aminoethyl)deoxyuridine (5-NedU), Salmonella phage ViI (Vi1) with 5-(2-aminoethoxy)methyldeoxyuridine (5-NeOmdU) and Delftia phage phi W-14 (a.k.a. ΦW-14) with α-putrescinylthymidine (putT). Among >200 commercially available restriction endonucleases (REases) tested, phage M6, ViI, and phi W-14 genomic DNAs (gDNA) show resistance against 48.4, 71.0, and 68.8% of Type II restrictions, respectively. Inspection of the resistant sites indicates the presence of conserved dinucleotide TG or TC (TS, S=C, or G), implicating the specificity of TS sequence as the target that is converted to modified base in the genomes. We also tested a number of DNA methyltransferases (MTases) on these phage DNAs and found some MTases can fully or partially modify the DNA to confer more resistance to cleavage by REases. Phage M6 restriction fragments can be efficiently ligated by T4 DNA ligase. Phi W-14 restriction fragments show apparent reduced rate in E. coli exonuclease III degradation. This work extends previous studies that hypermodified T derived from 5hmdU provides additional resistance to host-encoded restrictions, in parallel to modified cytosines, guanine, and adenine in phage genomes. The results reported here provide a general guidance to use REases to map and clone phage DNA with hypermodified thymidine.

Trust in the Work Environment and Cardiovascular Disease Risk: Findings from the Gallup-Sharecare Well-Being Index

This study examined associations between trust, an important aspect of workplace social capital, with seven cardiovascular disease (CVD) risk factors (American Heart Association Life’s Simple 7 (LS7)): smoking, obesity, low physical activity, poor diet, diabetes, high cholesterol, and high blood pressure. Data are from the U.S. Gallup-Sharecare Well-Being Index (2010–2012), a nationally representative telephone survey of U.S. workers (n = 412,884). The independent variable was the response to a work environment (WE) question as to whether their supervisor always creates an open and trusting environment. Regression models were adjusted for demographic characteristics with each of the LS7 CVD risk factors as dependent variables. Twenty-one percent of workers reported that their supervisor did not create an open and trusting environment. Trust was associated with increased adjusted odds of having many of the LS7 CVD risk factors. Among those workers whose supervisor created a mistrustful environment, the odds ratios were greatest (>20%) for having four or more of the LS7 CVD risk factors.

Role of cystathionine β-synthase in human breast Cancer

Cystathionine β-synthase (CBS) is an enzyme in the transulfuration pathway that can catalyze the condensation of homocysteine (Hcy) and cysteine (Cys) to hydrogen sulfide (H2S) and cystathionine (CTH). CBS-derived H2S is important in angiogenesis and drug resistance in colon and ovarian cancers, respectively. However, the mechanisms by which cancer cell-derived H2S is utilized by cancer cells as a protective agent against host-derived activated macrophages are not yet investigated. This study investigated the mechanistic role of CBS-derived H2S in the protection of human breast cancer (HBC) cells against activated macrophages. HBC patient-derived tissue arrays and immunoblot analysis of HBC cells exhibited significantly increased levels of CBS when compared with their normal counterparts. This was associated with increased levels of H2S and CTH. Silencing of CBS in HBC cells caused a significant decrease in the levels of H2S and CTH but did not affect the growth of these cells per se, in in vitro cultures. However CBS-silenced cells exhibited significantly reduced growth in the presence of activated macrophages and in xenograft models. This was associated with an increase in the steady state levels of reactive aldehyde-derived protein adducts. Exogenous addition of H2S countered the effects of CBS silencing in the presence of macrophages. Conversely overexpression of CBS in human breast epithelial (HBE) cells (which do not naturally express CBS) protected them from activated macrophages, which were otherwise susceptible to the latter.

Effect of the cathepsin K inhibitor odanacatib administered once weekly on bone mineral density in Japanese patients with osteoporosis--a double-blind, randomized, dose-finding study

The efficacy and safety of oral placebo or odanacatib 10, 25, or 50 mg once weekly for 52 weeks were evaluated in a double-blind, randomized, multi-center study in Japanese female and male patients with osteoporosis.

INTRODUCTION

Odanacatib is a selective and reversible cathepsin K inhibitor that decreases bone resorption and increases bone mineral density (BMD).

METHODS

The primary efficacy endpoint was percent change from baseline to week 52 in lumbar spine BMD. Secondary endpoints included percent change in total hip, femoral neck, and trochanter BMD and in bone biomarkers after treatment for 52 weeks.

RESULTS

In this study, 286 patients [94% female, mean age (SD) 68.2 (7.1) years] were included in the analysis. The least-squares mean percent changes from baseline to week 52 in the groups receiving placebo, 10, 25 and 50 mg of odanacatib for lumbar spine (L1~L4) BMD were 0.5, 4.1, 5.7, and 5.9% and for total hip BMD were -0.4, 1.3, 1.8, and 2.7%, respectively. The changes in femoral neck and trochanter BMD were similar to those at the total hip. Bone turnover markers were reduced in a dose-dependent manner. However, the effects of odanacatib on bone formation markers were less compared with the effects on bone resorption markers. Tolerability and safety profiles were similar among all treatment groups with no dose-related trends in any adverse events.

CONCLUSIONS

Weekly odanacatib treatment for 52 weeks increased BMD at the lumbar spine and at all hip sites in a dose-dependent manner and was well tolerated in Japanese patients with osteoporosis.

Cys shotgun labeling of macrophages adhering to and engulfing Ig-opsonized cells

A method is being developed to study cytoskeletal reorganization in cell adhesion processes. The initial model process is adhesion and phagocytosis of beads or red blood cells by macrophages. Live cell labeling with Cys reactive fluorophores is performed before and during phagocytosis with different color labeling dyes. Since Cys is a relatively hydrophobic amino acid, its differential exposure and labeling in principle reflects changes in tertiary or quaternary structure of specific proteins. Similar studies conducted on red blood cells under fluid shear conditions showed that specific domains in spectrin undergo extensible unfolding within sheared cells. The initial work here with macrophages also suggests some structural changes in phagocytosis although the proteins and specific sites have yet to be identified.

Sleep duration and body mass index in a rural population

BACKGROUND

A growing body of epidemiological evidence suggests an association between short sleep duration and obesity. Recently, potential hormonal links have been observed that may account for the relationship. The possible connection between sleep duration and body mass index (BMI) has not been explored in rural populations. Rural populations are of interest because obesity rates are high and lifestyle patterns of nutrition, physical activity, work hours, and sleep may differ from those in urban and suburban populations. We conducted this study to determine whether short sleep duration is related to BMI and obesity in a rural population in southeast Iowa.

METHODS

We conducted a cross-sectional analysis of data collected in the Keokuk County Rural Health Cohort Study, 1999-2004. Study participants were from a population-based sample consisting of 990 employed adults in a rural community in southeastern Iowa. The main outcome measure was BMI. Multiple linear regression modeling was used to adjust for potential confounding variables.

RESULTS

Self-reported sleep duration on weeknights was negatively correlated (beta = -0.42; 95% confidence interval, -0.77 to -0.07) with higher BMI after adjusting for sex, age, educational achievement, physical job demand, household income, depressive symptoms, marital status, alcohol consumption, and snoring.

CONCLUSION

These data support an association between short sleep duration and higher BMI in this rural population, which is consistent with the relationship found in other settings.

The ‘metabolon’, CD47, and the ‘phagocytic synapse’: molecular co-localization and species divergence

CD47 is a widely expressed integral membrane protein, found also on red blood cells where it reportedly has a key role in inhibiting phagocytic clearance of RBC by signaling within a multi-molecular 'phagocytic synapse'. Calreticulin is postulated to be on the RBC surface and stimulate phagocytosis, whereupon CD47 on the RBC binds SIRPalpha on the phagocyte and signals a block against phagocytosis. While studies of mouse suggest such an inhibitory role for CD47, CD47 seems to have distinct interactions in human RBC--particularly within a 'metabolon' complex of CD47, Rh proteins, and several other proteins. We have assessed the relative density, co-clustering, and mobility of some of the implicated proteins on human RBC versus murine RBC (hu-RBC and mu-RBC, respectively), and we find a few major differences. While RBC from both species express similar densities of CD47 and SIRPalpha interactions are measurably modest, the interactions prove species-specific. While RBC from both species also have detectable calreticulin, fresh hu-RBC are found to have 10-100-fold more calreticulin binding sites on their surface. Imaging of clusters of SIRPalpha-CD47 on both species of RBC show that RhD does co-localize with CD47 on hu-RBC, but neither calreticulin nor Glycophorin-A appear enriched in the metabolon complexes. Furthermore, mouse-cells alone tend to aggregate due to cross-bridging by SIRPalpha complexes, showing accumulation of CD47 in the adhesion zone, which is consistent with a high mobility of CD47 unique to mu-RBC.

Sequence variation within botulinum neurotoxin serotypes impacts antibody binding and neutralization

The botulinum neurotoxins (BoNTs) are category A biothreat agents which have been the focus of intensive efforts to develop vaccines and antibody-based prophylaxis and treatment. Such approaches must take into account the extensive BoNT sequence variability; the seven BoNT serotypes differ by up to 70% at the amino acid level. Here, we have analyzed 49 complete published sequences of BoNTs and show that all toxins also exhibit variability within serotypes ranging between 2.6 and 31.6%. To determine the impact of such sequence differences on immune recognition, we studied the binding and neutralization capacity of six BoNT serotype A (BoNT/A) monoclonal antibodies (MAbs) to BoNT/A1 and BoNT/A2, which differ by 10% at the amino acid level. While all six MAbs bound BoNT/A1 with high affinity, three of the six MAbs showed a marked reduction in binding affinity of 500- to more than 1,000-fold to BoNT/A2 toxin. Binding results predicted in vivo toxin neutralization; MAbs or MAb combinations that potently neutralized A1 toxin but did not bind A2 toxin had minimal neutralizing capacity for A2 toxin. This was most striking for a combination of three binding domain MAbs which together neutralized >40,000 mouse 50% lethal doses (LD(50)s) of A1 toxin but less than 500 LD(50)s of A2 toxin. Combining three MAbs which bound both A1 and A2 toxins potently neutralized both toxins. We conclude that sequence variability exists within all toxin serotypes, and this impacts monoclonal antibody binding and neutralization. Such subtype sequence variability must be accounted for when generating and evaluating diagnostic and therapeutic antibodies.

Molecular Evolution of Antibody Affinity for Sensitive Detection of Botulinum Neurotoxin Type A

Botulism is caused by botulinum neurotoxin (BoNT), the most poisonous substance known. Potential use of BoNT as a biothreat agent has made development of sensitive assays for toxin detection and potent antitoxin for treatment of intoxication a high priority. To improve detection and treatment of botulism, molecular evolution and yeast display were used to increase the affinity of two neutralizing single chain Fv (scFv) antibodies binding BoNT serotype A (BoNT/A). Selection of yeast displayed scFv libraries was performed using methods to select for both increased association rate constant (k(on)) and decreased dissociation rate constants (k(off)). A single cycle of error prone mutagenesis increased the affinity of the 3D12 scFv 45-fold from a K(D) of 9.43x10(-10)M to a K(D) of 2.1x10(-11)M. Affinity of the HuC25 scFv was increased 37-fold from 8.44x10(-10)M to 2.26x10(-11)M using libraries constructed by both random and site directed mutagenesis. scFv variable region genes were used to construct IgG for use in detection assays and in vivo neutralization studies. While IgG had the same relative increases in affinity as scFv, (35-fold and 81-fold, respectively, for 3D12 and HuC25) higher solution equilibrium binding constants were observed for the IgG, with the 3D12 K(D) increasing from 6.07x10(-11)M to 1.71x10(-12)M and the HuC25 K(D) increasing from 4.51x10(-11)M to 5.54x10(-13)M. Affinity increased due to both an increase in k(on), as well as slowing of k(off). Higher affinity antibodies had increased sensitivity, allowing detection of BoNT/A at concentrations as low as 1x10(-13)M. The antibodies will also allow testing of the role of affinity in in vivo toxin neutralization and could lead to the generation of more potent antitoxin.

Patterns of lung function in asymptomatic nonsmoking men and women in the People's Republic of China

PURPOSE

To evaluate patterns of lung function in healthy, working Chinese men and women in different geographic areas of the People's Republic of China (PRC).

METHODS

We conducted lung function tests on 2926 asymptomatic, never smoking Chinese men and women aged 35-56 years residing in or around Beijing and Guangzhou. Within each of these locations, separate urban and rural samples were recruited.

RESULTS

Age and height adjusted lung function was greater in Beijing than in Guangzhou, and within each city for residents of rural vs. urban areas. Among women, estimated rates of lung aging were greater in Beijing than in Guangzhou, and in urban vs. rural areas. Both FEV(1) and FVC exhibited a curvilinear association with body mass index.

CONCLUSIONS

Lung function data from this largely working cohort exhibited marked geographic and urban-rural differences in this never smoking, adult Chinese cohort. Such variation is not uncommon and may reflect differences in body size, diet, and environmental and occupational exposures across these different settings. Caution should be used in applying published reference equations to populations from different parts of the PRC.

An approach for evaluating aerosol particle deposition from a natural convection flow onto a vertical flat plate

An approach through numerical integration for evaluating aerosol particle deposition onto a vertical flat plate is proposed. The airflow was based on the assumption of a two-dimensional, incompressible and steady state laminar flow driven by a buoyancy force. The mechanisms of particle deposition were coupled from natural convection, Brownian diffusion, thermophoresis and electrophoresis due to constant electric strength. This approach demonstrated an easier method of prediction and produced a very good agreement with the thermophoresis exact solution. Results described the role of thermophoretic and electrophoretic forces on particle deposition. The thermophoresis effect was predicted to be particularly important for particles of d(p)>/=0.1 microm moving toward a cold surface or away from a hot surface at a given temperature gradient. The electrophoresis effect dominates the deposition of submicron particles.

Synthesis of benzo[c]quinolizin-3-ones: selective non-steroidal inhibitors of steroid 5 alpha-reductase 1

A short and efficient synthesis of novel benzo[c]quinolizin-3-one derivatives is described. The synthesis is based on the tandem Mannich-Michael cyclization between 2-silyloxy-1,3-butadienes and a N-t-Boc iminium ion. The prepared derivatives are selective inhibitors of human steroid 5 alpha-reductase isoenzyme 1, thus having potential application as drugs for treatment of male pattern baldness and other DHT-dependent skin disorders.

Relationship between lung function and blood pressure in Chinese men and women of Beijing and Guangzhou. PRC-USA Cardiovascular and Cardiopulmonary Epidemiology Research Group

BACKGROUND

Previous studies of western populations have shown an inverse association between lung function and blood pressure.

METHODS

As part of a People's Republic of China-United States cardiopulmonary epidemiology study, we investigated the cross-sectional relationship between lung function and blood pressure in 6757 Chinese men and women, aged 35-54, from Beijing and Guangzhou, China. We also evaluated the longitudinal association between lung function and incident hypertension among 4818 initially normotensive subjects followed up between 2 and 4 years later.

RESULTS

In our cross-sectional analyses of baseline data, lung function varied inversely with baseline systolic (SBP) and diastolic blood pressure (DBP) in all women and in Beijing men. This association held for absolute and height-standardized forced vital capacity (FVC) and one-second forced expiratory volume (FEV1) (correlations: 0.10, -0.18, P < 0.0001), but was weaker after adjustment for age (correlations: -0.02, -0.11). The longitudinal follow-up showed that lower initial lung function levels were associated with a higher incidence of hypertension (SBP > or = 140 mmHg or DBP > or = 90 mmHg or currently using antihypertensive medications), but only among women in Guangzhou. Relative risks for hypertension incidence for those in the two lowest quintiles for FEV1 and FVC, compared to those in the two highest quintiles, ranged from 1.9 to 2.3 for Guangzhou women and from 0.9 to 1.4 for all other gender-city subgroups. Logistic regression analyses adjusting for age, baseline SBP, body mass index, smoking, education, and urban versus rural setting generally confirmed these patterns.

CONCLUSIONS

These results suggest a statistically significant, though weak, inverse relationship between lung function and blood pressure in Chinese men and women. This association is largely attributable to age and is present prospectively only in women.

Automated utility assessment of global health

The objective of this study was to characterize the performance of an automated utility assessment instrument for measuring preferences for overall health. The study population consisted of 83 subjects recruited from the cafeteria of a large tertiary care hospital. We assessed utilities for current health relative to perfect health and death using the rating scale, time tradeoff and standard gamble metrics. To validate the instrument, we compared utilities with the General Health subscale of the SF-36 Health Survey instrument, satisfaction with current health, and degree of bother due to current health. We evaluated interview failure rate based on irrational orderings of two practice assessments (monocular and binocular blindness) or inability to complete the interview. As expected, utility for overall health was statistically significantly associated with the General Health subscale score and measures of satisfaction with current health and degree of bother. There is substantial variation in utilities among patients with similarly severe overall health, and substantial overlap in utilities among subjects with different levels of overall health. The failure rate in the study was acceptable (9.6%). Automated assessment of utility for overall health provides a feasible means for estimating individual preferences.

Effects of cigarette smoking on lung function in four population samples in the People's Republic of China. The PRC-US Cardiovascular and Cardiopulmonary Epidemiology Research Group

As part of an ongoing study of cardiopulmonary risk factors in the People's Republic of China, we conducted lung function tests and obtained information about smoking habits on 6,765 Chinese men and women 35 to 56 yr of age residing in or around Beijing in the north and in or around Guangzhou in the south. Within each region, separate urban and rural populations were recruited. This study examined the relationship between tobacco consumption (both manufactured cigarettes and leaf tobacco) and lung function in a subset of current smokers and never smokers who had acceptable lung function data. All methods were strictly standardized. Overall, tobacco smoking was associated with a statistically significant mean difference in FEV1 among men (-89 ml) and women (-52 ml) relative to never smokers after adjusting for age, height, and residence. Differences between smokers of cigarettes and smokers of leaf tobacco were not significant. Among the subset of smokers who smoked only cigarettes, this decrement increased with increasing duration of cigarette smoking, but it was small (-4 ml/yr of smoking for FEV1 for both men and women) in comparison with the effects of smoking reported from western countries. Although the smoking effect tended to increase with increasing dose, these differences were small and generally not statistically significant. The relatively small smoking effect in this study may result from differences between developed and developing countries in the cumulative dose of tobacco products. Alternative explanations or contributing factors such as racial differences in susceptibility and differences in the form and delivery of tobacco cannot be discounted.

A north-south comparison of blood pressure and factors related to blood pressure in the People's Republic of China: a report from the PRC-USA Collaborative Study of Cardiovascular Epidemiology

OBJECTIVES

To compare blood pressures in northern (Beijing) and southern (Guangzhou) Chinese population samples aged 35-54 years, males and females, urban and rural, and to assess the role of blood pressure-related traits in explaining north-south differences.

DESIGN

Cross-sectional surveys were conducted in 1983-1984 of northern and southern populations employed in industry (urban) or farming (rural).

METHODS

In the north samples were selected from the Capital Iron and Steel Complex (urban) and Shijingshan district (rural); in the south samples from the Guangzhou Shipyard (urban) and Panyu County (rural) were used.

RESULTS

The number of subjects surveyed in north and south were 4706 and 4179, respectively: 1500 and 1052 urban males, and 717 and 914 rural males; and 1300 and 1061 urban females, and 1189 and 1152 rural females, respectively. Average systolic (SBP) and diastolic (DBP) blood pressures, were consistently higher in the north than in the south. SBP and DBP were significantly and independently related to age, body mass index, heart rate, use of antihypertensive drugs, serum triglycerides level, alcohol use (males only) and inversely to cigarette smoking. Northerners were older, taller, heavier and had higher body mass index and triglycerides level than southerners. With adjustment of SBP and DBP for blood pressure-related traits, north-south blood pressure differences decreased, but remained significant for urban males, rural males and rural females, with sizeable differences for rural samples in particular.

CONCLUSIONS

North-south differences in blood pressure in these samples are accounted for only partly by north-south differences in the cited blood pressure-related traits. The role of other traits requires assessment.

Regulation of hepatic growth hormone receptors in coho salmon (Oncorhynchus kisutch)

Factors potentially regulating hepatic growth hormone (GH) receptors in coho salmon (Oncorhynchus kisutch) have been investigated. From December to June of the first year, relative changes in hepatic 125I-sGH binding and 35SO4 incorporation by ceratobranchial cartilage were similar. Stunted salmon, which in seawater have elevated plasma GH yet fail to grow, showed lower hepatic 125I-sGH binding than did normally growing seawater salmon. However, MgCl2 treatment of stunts' membranes to reveal total specific binding of 125I-sGH indicated receptor occupation by endogenous sGH. Total specific 125I-sGH binding was low in seawater stunts and remained low if these fish remained unfed after return to fresh water, but increased approximately twofold upon feeding. Total specific binding in fasted salmon in fresh water showed a trend toward decreased levels by 1 week; by 3 weeks, binding was 40% lower than in fed fish. There was a positive correlation (r = 0.600) between condition factor and total specific binding in fed and fasted salmon in fresh water. Two weeks after hypophysectomy total specific binding was 50% lower than in sham-operated control salmon, indicating pituitary regulation of GH receptors. GH treatment reduced both free and total 125I-sGH binding in salmon examined 24 hr after treatment. Treatment with recombinant bovine insulin-like growth factor I, thyroxine, or cortisol did not affect free 125I-sGH binding. Both the pituitary and nutrition appear to be prime regulators of hepatic GH receptors in coho salmon.

Prevention of human immunodeficiency virus infection among intravenous drug users in New South Wales, Australia: the needles and syringes distribution programme through retail pharmacies

Prevalence of Human Immunodeficiency Virus (HIV) infection among 12, 000 intravenous (i.v.) drug users in New South Wales (NSW) was estimated to be very low in 1985. However, a large increase of HIV infection in this population group could result within a short period.

The NSW government amended existing legislation to permit the sale and possession of sterile needles and syringes. A programme to promote the sale of needles and syringes was launched jointly with the Pharmacy Guild of Australia (NSW Branch) in December 1986. Favourable changes in pharmacists' attitudes were noted four months later. The distribution scheme became an important component of the NSW prevention programme.

There are 2, 039 retail pharmacies throughout NSW. The number of sterile needles and syringes sold through these outlets increased from 4, 200 in January 1987 to 51, 000 in November 1987 with a total of 422, 000 dispensed over this period. The percentage of Pharmacy Guild members involved in the programme increased from 0.5% to 22.5%, covering 38% of the state by November 1987.

During 1987, HIV infection among i.v. drug users remained low. This suggests that the needles and syringes distribution programme contributed significantly towards limiting the spread of HIV infection among i.v. drug users.

Dietary model for production of experimental zinc deficiency in man

A semipurified diet based on soy protein was developed to induce mild zinc deficiency in five male volunteers. Each of seven daily menus provided (mean +/- SD) 2248 +/- 128 kcal, 56.6 +/- 5.7 protein, 261 +/- 30 g carbohydrate, 110 +/- 21 g fat, 8.5 +/- 1.4 g fiber, and 4.8 +/- 1.3 mg zinc. The analytical value for phytate:zinc molar ratio was 21 +/- 9. One subject, who received five of the menus for 28 wk, lost approximately 200 mg body zinc and 7% weight; zinc concentration declined 25% in plasma, 30% in lymphocytes, and 55% in neutrophils. This dietary model allowed simple formulation of new menus for subjects in diverse states of health. It caused no ill effects after prolonged consumption, and all deficiency symptoms were reversed by zinc supplementation of 30 mg/d for 20 wk. With simple manipulation, this dietary model may be used safely for gradual induction of zinc and/or other micronutrient deficiencies in humans.

Vasopressin as a possible contributor to hypertension

The role of vasopressin as a pressor agent to the hypertensive process was examined. Vasopressin plays a major role in the pathogenesis of DOCA-salt hypertension, since the elevation of blood pressure was not substantial in the rats with lithium-treated diabetes insipidus after DOCA-salt treatment. Administration of DDAVP which has antidiuretic action but minimal vasopressor effect failed to increase blood pressure to the levels observed after administration of AVP. Furthermore, the pressor action of vasopressin appears to be important in the development of this model of hypertension, since the enhanced pressor responsiveness to the hormone was observed in the initial stage of hypertension. Increased secretion of vasopressin from neurohypophysis also promotes the function of the hormone as a pathogenetic factor in hypertension. An unproportional release of vasopressin compared to plasma osmolality may be induced by the absence of an adjusting control of angiotensin II forming and receptor binding capacity for sodium balance in the brain. However, the role of vasopressin remains to be determined in human essential hypertension.

Spin-state changes in cytochrome P-450cam on binding of specific substrates

The electron paramagnetic resonance signals of the soluble P-450 cytochrome from Pseudomonas putida were observed at temperatures from 4.2 to 80 degrees K. As isolated, P-450 has a signal typical of a low spin ferric-heme compound with sulfur as one of the axial ligands (g = 2.45, 2.26, 1.91(5)). We also detected a minor signal typical of high spin ferric heme (g = 8, 4, 1.8) equivalent to less than 7% of the heme at temperatures below 20 degrees K. On titration with the substrate, (+)-camphor, the low spin signal decreased and the high spin signal increased, maximally representing about 60% of the heme. For reasons not thus far understood, 40% of the heme is not converted to high spin by either (+) or (-)-camphor. The high spin signal has a rhombic character which is stronger than any previously observed with a heme compound (E = 0.33 cm(-1); D = 3.8 cm(-1); E/D = 0.087). We conclude that P-450(cam) as isolated is equal to or more than 95% in a low spin form probably having sulfur as one of the axial ligands. The binding of substrate displaces this ligand sufficiently to allow for conversion from a low to a high spin form.