Impacts of human mobility on the citywide transmission dynamics of 18 respiratory viruses in pre- and post-COVID-19 pandemic years

Many studies have used mobile device location data to model SARS-CoV-2 dynamics, yet relationships between mobility behavior and endemic respiratory pathogens are less understood. We studied the effects of population mobility on the transmission of 17 endemic viruses and SARS-CoV-2 in Seattle over a 4-year period, 2018-2022. Before 2020, visits to schools and daycares, within-city mixing, and visitor inflow preceded or coincided with seasonal outbreaks of endemic viruses. Pathogen circulation dropped substantially after the initiation of COVID-19 stay-at-home orders in March 2020. During this period, mobility was a positive, leading indicator of transmission of all endemic viruses and lagging and negatively correlated with SARS-CoV-2 activity. Mobility was briefly predictive of SARS-CoV-2 transmission when restrictions relaxed but associations weakened in subsequent waves. The rebound of endemic viruses was heterogeneously timed but exhibited stronger, longer-lasting relationships with mobility than SARS-CoV-2. Overall, mobility is most predictive of respiratory virus transmission during periods of dramatic behavioral change and at the beginning of epidemic waves.

Utilizing a university testing program to estimate relative effectiveness of monovalent COVID-19 mRNA booster vaccine versus two-dose primary series against symptomatic SARS-CoV-2 infection

Vaccine effectiveness (VE) studies utilizing the test-negative design are typically conducted in clinical settings, rather than community populations, leading to bias in VE estimates against mild disease and limited information on VE in healthy young adults. In a community-based university population, we utilized data from a large SARS-CoV-2 testing program to estimate relative VE of COVID-19 mRNA vaccine primary series and monovalent booster dose versus primary series only against symptomatic SARS-CoV-2 infection from September 2021 to July 2022. We used the test-negative design and logistic regression implemented via generalized estimating equations adjusted for age, calendar time, prior SARS-CoV-2 infection, and testing frequency (proxy for test-seeking behavior) to estimate relative VE. Analyses included 2,218 test-positive cases (59 % received monovalent booster dose) and 9,615 test-negative controls (62 %) from 9,066 individuals, with median age of 21 years, mostly students (71 %), White (56 %) or Asian (28 %), and with few comorbidities (3 %). More cases (23 %) than controls (6 %) had COVID-19-like illness. Estimated adjusted relative VE of primary series and monovalent booster dose versus primary series only against symptomatic SARS-CoV-2 infection was 40 % (95 % CI: 33-47 %) during the overall analysis period and 46 % (39-52 %) during the period of Omicron circulation. Relative VE was greater for those without versus those with prior SARS-CoV-2 infection (41 %, 34-48 % versus 33 %, 9 %-52 %, P < 0.001). Relative VE was also greater in the six months after receiving a booster dose (41 %, 33-47 %) compared to more than six months (27 %, 8-42 %), but this difference was not statistically significant (P = 0.06). In this relatively young and healthy adult population, an mRNA monovalent booster dose provided increased protection against symptomatic SARS-CoV-2 infection, overall and with the Omicron variant. University testing programs may be utilized for estimating VE in healthy young adults, a population that is not well-represented by routine VE studies.

Tiny swabs: nasal swabs integrated into tube caps facilitate large-scale self-collected SARS-CoV-2 testing

The COVID-19 pandemic spurred the development of innovative solutions for specimen collection and molecular detection for large-scale community testing. Among these developments is the RHINOstic nasal swab, a plastic anterior nares swab built into the cap of a standard matrix tube that facilitates automated processing of up to 96 specimens at a time. In a study of unsupervised self-collection utilizing these swabs, we demonstrate comparable analytic performance and shipping stability compared to traditional anterior nares swabs, as well as significant improvements in laboratory processing efficiency. The use of these swabs may allow laboratories to accommodate large numbers of sample collections during periods of high testing demand. Automation-friendly nasal swabs are an important tool for high-throughput processing of samples that may be adopted in response to future respiratory viral pandemics.

Incidence of SARS-CoV-2 infection and associated risk factors among staff and residents at homeless shelters in King County, Washington: an active surveillance study

Homeless shelter residents and staff may be at higher risk of SARS-CoV-2 infection. However, SARS-CoV-2 infection estimates in this population have been reliant on cross-sectional or outbreak investigation data. We conducted routine surveillance and outbreak testing in 23 homeless shelters in King County, Washington, to estimate the occurrence of laboratory-confirmed SARS-CoV-2 infection and risk factors during 1 January 2020-31 May 2021. Symptom surveys and nasal swabs were collected for SARS-CoV-2 testing by RT-PCR for residents aged ≥3 months and staff. We collected 12,915 specimens from 2,930 unique participants. We identified 4.74 (95% CI 4.00-5.58) SARS-CoV-2 infections per 100 individuals (residents: 4.96, 95% CI 4.12-5.91; staff: 3.86, 95% CI 2.43-5.79). Most infections were asymptomatic at the time of detection (74%) and detected during routine surveillance (73%). Outbreak testing yielded higher test positivity than routine surveillance (2.7% versus 0.9%). Among those infected, residents were less likely to report symptoms than staff. Participants who were vaccinated against seasonal influenza and were current smokers had lower odds of having an infection detected. Active surveillance that includes SARS-CoV-2 testing of all persons is essential in ascertaining the true burden of SARS-CoV-2 infections among residents and staff of congregate settings.

Streptococcus pneumoniae nasal carriage patterns with and without common respiratory virus detections in households in Seattle, WA, USA before and during the COVID-19 pandemic

Background

Respiratory viruses might influence Streptococcus pneumoniae nasal carriage and subsequent disease risk. We estimated the association between common respiratory viruses and semiquantitative S. pneumoniae nasal carriage density in a household setting before and during the COVID-19 pandemic.

Methods

From November 2019-June 2021, we enrolled participants in a remote household surveillance study of respiratory pathogens. Participants submitted weekly reports of acute respiratory illness (ARI) symptoms. Mid-turbinate or anterior nasal swabs were self-collected at enrollment, when ARI occurred, and, in the second year of the study only, from household contacts after SARS-CoV-2 was detected in a household member. Specimens were tested using multiplex reverse-transcription PCR for respiratory pathogens, including S. pneumoniae, rhinovirus, adenovirus, common human coronavirus, influenza A/B virus, respiratory syncytial virus (RSV) A/B, human metapneumovirus, enterovirus, and human parainfluenza virus. We estimated differences in semiquantitative S. pneumoniae nasal carriage density, estimated by the inverse of S. pneumoniae relative cycle threshold (Crt) values, with and without viral detection for any virus and for specific respiratory viruses using linear generalized estimating equations of S. pneumoniae Crt values on virus detection adjusted for age and swab type and accounting for clustering of swabs within households.

Results

We collected 346 swabs from 239 individuals in 151 households that tested positive for S. pneumoniae (n = 157 with and 189 without ≥1 viruses co-detected). Difficulty breathing, cough, and runny nose were more commonly reported among individuals with specimens with viral co-detection compared to without (15%, 80% and 93% vs. 8%, 57%, and 51%, respectively) and ear pain and headache were less commonly reported (3% and 26% vs. 16% and 41%, respectively). For specific viruses among all ages, semiquantitative S. pneumoniae nasal carriage density was greater with viral co-detection for enterovirus, RSV A/B, adenovirus, rhinovirus, and common human coronavirus (P < 0.01 for each). When stratified by age, semiquantitative S. pneumoniae nasal carriage density was significantly greater with viral co-detection among children aged <5 (P = 0.002) and 5-17 years (P = 0.005), but not among adults aged 18-64 years (P = 0.29).

Conclusion

Detection of common respiratory viruses was associated with greater concurrent S. pneumoniae semiquantitative nasal carriage density in a household setting among children, but not adults.

Results from a test-and-treat study for influenza among residents of homeless shelters in King County, WA: A stepped-wedge cluster-randomized trial

BACKGROUND

Persons experiencing homelessness face increased risk of influenza as overcrowding in congregate shelters can facilitate influenza virus spread. Data regarding on-site influenza testing and antiviral treatment within homeless shelters remain limited.

METHODS

We conducted a cluster-randomized stepped-wedge trial of point-of-care molecular influenza testing coupled with antiviral treatment with baloxavir or oseltamivir in residents of 14 homeless shelters in Seattle, WA, USA. Residents ≥3 months with cough or ≥2 acute respiratory illness (ARI) symptoms and onset <7 days were eligible. In control periods, mid-nasal swabs were tested for influenza by reverse transcription polymerase chain reaction (RT-PCR). The intervention period included on-site rapid molecular influenza testing and antiviral treatment for influenza-positives if symptom onset was <48 h. The primary endpoint was monthly influenza virus infections in the control versus intervention periods. Influenza whole genome sequencing was performed to assess transmission and antiviral resistance.

RESULTS

During 11/15/2019-4/30/2020 and 11/2/2020-4/30/2021, 1283 ARI encounters from 668 participants were observed. Influenza virus was detected in 51 (4%) specimens using RT-PCR (A = 14; B = 37); 21 influenza virus infections were detected from 269 (8%) intervention-eligible encounters by rapid molecular testing and received antiviral treatment. Thirty-seven percent of ARI-participant encounters reported symptom onset < 48 h. The intervention had no effect on influenza virus transmission (adjusted relative risk 1.73, 95% confidence interval [CI] 0.50-6.00). Of 23 influenza genomes, 86% of A(H1N1)pdm09 and 81% of B/Victoria sequences were closely related.

CONCLUSION

Our findings suggest feasibility of influenza test-and-treat strategies in shelters. Additional studies would help discern an intervention effect during periods of increased influenza activity.

The PERCIVAL detector: first user experiments

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.

Trends in Risk Factors and Symptoms Associated With SARS-CoV-2 and Rhinovirus Test Positivity in King County, Washington, June 2020 to July 2022

IMPORTANCE

Few US studies have reexamined risk factors for SARS-CoV-2 positivity in the context of widespread vaccination and new variants or considered risk factors for cocirculating endemic viruses, such as rhinovirus.

OBJECTIVES

To evaluate how risk factors and symptoms associated with SARS-CoV-2 test positivity changed over the course of the pandemic and to compare these with the risk factors associated with rhinovirus test positivity.

DESIGN, SETTING, AND PARTICIPANTS

This case-control study used a test-negative design with multivariable logistic regression to assess associations between SARS-CoV-2 and rhinovirus test positivity and self-reported demographic and symptom variables over a 25-month period. The study was conducted among symptomatic individuals of all ages enrolled in a cross-sectional community surveillance study in King County, Washington, from June 2020 to July 2022.

EXPOSURES

Self-reported data for 15 demographic and health behavior variables and 16 symptoms.

MAIN OUTCOMES AND MEASURES

Reverse transcription-polymerase chain reaction-confirmed SARS-CoV-2 or rhinovirus infection.

RESULTS

Analyses included data from 23 498 individuals. The median (IQR) age of participants was 34.33 (22.42-45.08) years, 13 878 (59.06%) were female, 4018 (17.10%) identified as Asian, 654 (2.78%) identified as Black, and 2193 (9.33%) identified as Hispanic. Close contact with an individual with SARS-CoV-2 (adjusted odds ratio [aOR], 3.89; 95% CI, 3.34-4.57) and loss of smell or taste (aOR, 3.49; 95% CI, 2.77-4.41) were the variables most associated with SARS-CoV-2 test positivity, but both attenuated during the Omicron period. Contact with a vaccinated individual with SARS-CoV-2 (aOR, 2.03; 95% CI, 1.56-2.79) was associated with lower odds of testing positive than contact with an unvaccinated individual with SARS-CoV-2 (aOR, 4.04; 95% CI, 2.39-7.23). Sore throat was associated with Omicron infection (aOR, 2.27; 95% CI, 1.68-3.20) but not Delta infection. Vaccine effectiveness for participants fully vaccinated with a booster dose was 93% (95% CI, 73%-100%) for Delta, but not significant for Omicron. Variables associated with rhinovirus test positivity included being younger than 12 years (aOR, 3.92; 95% CI, 3.42-4.51) and experiencing a runny or stuffy nose (aOR, 4.58; 95% CI, 4.07-5.21). Black race, residing in south King County, and households with 5 or more people were significantly associated with both SARS-CoV-2 and rhinovirus test positivity.

CONCLUSIONS AND RELEVANCE

In this case-control study of 23 498 symptomatic individuals, estimated risk factors and symptoms associated with SARS-CoV-2 infection changed over time. There was a shift in reported symptoms between the Delta and Omicron variants as well as reductions in the protection provided by vaccines. Racial and sociodemographic disparities persisted in the third year of SARS-CoV-2 circulation and were also present in rhinovirus infection. Trends in testing behavior and availability may influence these results.

The clinical and genomic epidemiology of seasonal human coronaviruses in congregate homeless shelter settings: A repeated cross-sectional study

Background

The circulation of respiratory viruses poses a significant health risk among those residing in congregate settings. Data are limited on seasonal human coronavirus (HCoV) infections in homeless shelter settings.

Methods

We analysed data from a clinical trial and SARS-CoV-2 surveillance study at 23 homeless shelter sites in King County, Washington between October 2019-May 2021. Eligible participants were shelter residents aged ≥3 months with acute respiratory illness. We collected enrolment data and nasal samples for respiratory virus testing using multiplex RT-PCR platform including HCoV. Beginning April 1, 2020, eligibility expanded to shelter residents and staff regardless of symptoms. HCoV species was determined by RT-PCR with species-specific primers, OpenArray assay or genomic sequencing for samples with an OpenArray relative cycle threshold <22.

Findings

Of the 14,464 samples from 3281 participants between October 2019-May 2021, 107 were positive for HCoV from 90 participants (median age 40 years, range: 0·9-81 years, 38% female). HCoV-HKU1 was the most common species identified before and after community-wide mitigation. No HCoV-positive samples were identified between May 2020-December 2020. Adults aged ≥50 years had the highest detection of HCoV (11%) among virus-positive samples among all age-groups. Species and sequence data showed diversity between and within HCoV species over the study period.

Interpretation

HCoV infections occurred in all congregate homeless shelter site age-groups with the greatest proportion among those aged ≥50 years. Species and sequencing data highlight the complexity of HCoV epidemiology within and between shelters sites.

Funding

Gates Ventures, Centers for Disease Control and Prevention, National Institute of Health.

SARS-CoV-2 Screening Testing in Schools: A Comparison of School- Vs. Home-Based Collection Methods

We implemented a voluntary SARS-CoV-2 screening testing study for kindergarten-2nd grade students in a Washington School district. Weekly SARS-CoV-2 testing participation was higher for students with staff-collected nasal swabs at school than for students with parent-collected swabs at home.

The Clinical and Genomic Epidemiology of Rhinovirus in Homeless Shelters-King County, Washington

BACKGROUND

Rhinovirus (RV) is a common cause of respiratory illness in all people, including those experiencing homelessness. RV epidemiology in homeless shelters is unknown.

METHODS

We analyzed data from a cross-sectional homeless shelter study in King County, Washington, October 2019-May 2021. Shelter residents or guardians aged ≥3 months reporting acute respiratory illness completed questionnaires and submitted nasal swabs. After 1 April 2020, enrollment expanded to residents and staff regardless of symptoms. Samples were tested by multiplex RT-PCR for respiratory viruses. A subset of RV-positive samples was sequenced.

RESULTS

There were 1066 RV-positive samples with RV present every month of the study period. RV was the most common virus before and during the coronavirus disease 2019 (COVID-19) pandemic (43% and 77% of virus-positive samples, respectively). Participants from family shelters had the highest prevalence of RV. Among 131 sequenced samples, 33 RV serotypes were identified with each serotype detected for ≤4 months.

CONCLUSIONS

RV infections persisted through community mitigation measures and were most prevalent in shelters housing families. Sequencing showed a diversity of circulating RV serotypes, each detected over short periods of time. Community-based surveillance in congregate settings is important to characterize respiratory viral infections during and after the COVID-19 pandemic.

CLINICAL TRIALS REGISTRATION

NCT04141917.

Remote Household Observation for Noninfluenza Respiratory Viral Illness

BACKGROUND

Noninfluenza respiratory viruses are responsible for a substantial burden of disease in the United States. Household transmission is thought to contribute significantly to subsequent transmission through the broader community. In the context of the coronavirus disease 2019 (COVID-19) pandemic, contactless surveillance methods are of particular importance.

METHODS

From November 2019 to April 2020, 303 households in the Seattle area were remotely monitored in a prospective longitudinal study for symptoms of respiratory viral illness. Enrolled participants reported weekly symptoms and submitted respiratory samples by mail in the event of an acute respiratory illness (ARI). Specimens were tested for 14 viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), using reverse-transcription polymerase chain reaction. Participants completed all study procedures at home without physical contact with research staff.

RESULTS

In total, 1171 unique participants in 303 households were monitored for ARI. Of participating households, 128 (42%) included a child aged <5 years and 202 (67%) included a child aged 5-12 years. Of the 678 swabs collected during the surveillance period, 237 (35%) tested positive for 1 or more noninfluenza respiratory viruses. Rhinovirus, common human coronaviruses, and respiratory syncytial virus were the most common. Four cases of SARS-CoV-2 were detected in 3 households.

CONCLUSIONS

This study highlights the circulation of respiratory viruses within households during the winter months during the emergence of the SARS-CoV-2 pandemic. Contactless methods of recruitment, enrollment, and sample collection were utilized throughout this study and demonstrate the feasibility of home-based, remote monitoring for respiratory infections.

Comparison of Symptoms and RNA Levels in Children and Adults With SARS-CoV-2 Infection in the Community Setting

Importance

The association between COVID-19 symptoms and SARS-CoV-2 viral levels in children living in the community is not well understood.

Objective

To characterize symptoms of pediatric COVID-19 in the community and analyze the association between symptoms and SARS-CoV-2 RNA levels, as approximated by cycle threshold (Ct) values, in children and adults.

Design, Setting, and Participants

This cross-sectional study used a respiratory virus surveillance platform in persons of all ages to detect community COVID-19 cases from March 23 to November 9, 2020. A population-based convenience sample of children younger than 18 years and adults in King County, Washington, who enrolled online for home self-collection of upper respiratory samples for SARS-CoV-2 testing were included.

Exposures

Detection of SARS-CoV-2 RNA by reverse transcription-polymerase chain reaction (RT-PCR) from participant-collected samples.

Main Outcomes and Measures

RT-PCR-confirmed SARS-CoV-2 infection, with Ct values stratified by age and symptoms.

Results

Among 555 SARS-CoV-2-positive participants (mean [SD] age, 33.7 [20.1] years; 320 were female [57.7%]), 47 of 123 children (38.2%) were asymptomatic compared with 31 of 432 adults (7.2%). When symptomatic, fewer symptoms were reported in children compared with adults (mean [SD], 1.6 [2.0] vs 4.5 [3.1]). Symptomatic individuals had lower Ct values (which corresponded to higher viral RNA levels) than asymptomatic individuals (adjusted estimate for children, -3.0; 95% CI, -5.5 to -0.6; P = .02; adjusted estimate for adults, -2.9; 95% CI, -5.2 to -0.6; P = .01). The difference in mean Ct values was neither statistically significant between symptomatic children and symptomatic adults (adjusted estimate, -0.7; 95% CI, -2.2 to 0.9; P = .41) nor between asymptomatic children and asymptomatic adults (adjusted estimate, -0.6; 95% CI, -4.0 to 2.8; P = .74).

Conclusions and Relevance

In this community-based cross-sectional study, SARS-CoV-2 RNA levels, as determined by Ct values, were significantly higher in symptomatic individuals than in asymptomatic individuals and no significant age-related differences were found. Further research is needed to understand the role of SARS-CoV-2 RNA levels and viral transmission.

SwabExpress: An end-to-end protocol for extraction-free covid-19 testing

BACKGROUND

The urgent need for massively scaled clinical testing for SARS-CoV-2, along with global shortages of critical reagents and supplies, has necessitated development of streamlined laboratory testing protocols. Conventional nucleic acid testing for SARS-CoV-2 involves collection of a clinical specimen with a nasopharyngeal swab in transport medium, nucleic acid extraction, and quantitative reverse transcription PCR (RT-qPCR) (1). As testing has scaled across the world, the global supply chain has buckled, rendering testing reagents and materials scarce (2). To address shortages, we developed SwabExpress, an end-to-end protocol developed to employ mass produced anterior nares swabs and bypass the requirement for transport media and nucleic acid extraction.

METHODS

We evaluated anterior nares swabs, transported dry and eluted in low-TE buffer as a direct-to-RT-qPCR alternative to extraction-dependent viral transport media. We validated our protocol of using heat treatment for viral inactivation and added a proteinase K digestion step to reduce amplification interference. We tested this protocol across archived and prospectively collected swab specimens to fine-tune test performance.

RESULTS

After optimization, SwabExpress has a low limit of detection at 2-4 molecules/uL, 100% sensitivity, and 99.4% specificity when compared side-by-side with a traditional RT-qPCR protocol employing extraction. On real-world specimens, SwabExpress outperforms an automated extraction system while simultaneously reducing cost and hands-on time.

CONCLUSION

SwabExpress is a simplified workflow that facilitates scaled testing for COVID-19 without sacrificing test performance. It may serve as a template for the simplification of PCR-based clinical laboratory tests, particularly in times of critical shortages during pandemics.

SwabExpress: An end-to-end protocol for extraction-free COVID-19 testing

BACKGROUND

The urgent need for massively scaled clinical testing for SARS-CoV-2, along with global shortages of critical reagents and supplies, has necessitated development of streamlined laboratory testing protocols. Conventional nucleic acid testing for SARS-CoV-2 involves collection of a clinical specimen with a nasopharyngeal swab in transport medium, nucleic acid extraction, and quantitative reverse transcription PCR (RT-qPCR) (1). As testing has scaled across the world, the global supply chain has buckled, rendering testing reagents and materials scarce (2). To address shortages, we developed SwabExpress, an end-to-end protocol developed to employ mass produced anterior nares swabs and bypass the requirement for transport media and nucleic acid extraction.

METHODS

We evaluated anterior nares swabs, transported dry and eluted in low-TE buffer as a direct-to-RT-qPCR alternative to extraction-dependent viral transport media. We validated our protocol of using heat treatment for viral activation and added a proteinase K digestion step to reduce amplification interference. We tested this protocol across archived and prospectively collected swab specimens to fine-tune test performance.

RESULTS

After optimization, SwabExpress has a low limit of detection at 2-4 molecules/uL, 100% sensitivity, and 99.4% specificity when compared side-by-side with a traditional RT-qPCR protocol employing extraction. On real-world specimens, SwabExpress outperforms an automated extraction system while simultaneously reducing cost and hands-on time.

CONCLUSION

SwabExpress is a simplified workflow that facilitates scaled testing for COVID-19 without sacrificing test performance. It may serve as a template for the simplification of PCR-based clinical laboratory tests, particularly in times of critical shortages during pandemics.

Comparable specimen collection from both ends of at-home mid-turbinate swabs

Unsupervised upper respiratory specimen collection is a key factor in the ability to massively scale SARS-CoV-2 testing. But there is concern that unsupervised specimen collection may produce inferior samples. Across two studies that included unsupervised at-home mid-turbinate specimen collection, ~1% of participants used the wrong end of the swab. We found that molecular detection of respiratory pathogens and a human biomarker were comparable between specimens collected from the handle of the swab and those collected correctly. Older participants were more likely to use the swab backwards. Our results suggest that errors made during home-collection of nasal specimens do not preclude molecular detection of pathogens and specialized swabs may be an unnecessary luxury during a pandemic.

Transient magnetic gratings on the nanometer scale

Laser-driven non-local electron dynamics in ultrathin magnetic samples on a sub-10 nm length scale is a key process in ultrafast magnetism. However, the experimental access has been challenging due to the nanoscopic and femtosecond nature of such transport processes. Here, we present a scattering-based experiment relying on a laser-induced electro- and magneto-optical grating in a Co/Pd ferromagnetic multilayer as a new technique to investigate non-local magnetization dynamics on nanometer length and femtosecond timescales. We induce a spatially modulated excitation pattern using tailored Al near-field masks with varying periodicities on a nanometer length scale and measure the first four diffraction orders in an x-ray scattering experiment with magnetic circular dichroism contrast at the free-electron laser facility FERMI, Trieste. The design of the periodic excitation mask leads to a strongly enhanced and characteristic transient scattering response allowing for sub-wavelength in-plane sensitivity for magnetic structures. In conjunction with scattering simulations, the experiment allows us to infer that a potential ultrafast lateral expansion of the initially excited regions of the magnetic film mediated by hot-electron transport and spin transport remains confined to below three nanometers.

Extracting depth information of 3-dimensional structures from a single-view X-ray Fourier-transform hologram

We demonstrate how information about the three-dimensional structure of an object can be extracted from a single Fourier-transform X-ray hologram. In contrast to lens-based 3D imaging approaches that provide depth information of a specimen utilizing several images from different angles or via adjusting the focus to different depths, our method capitalizes on the use of the holographically encoded phase and amplitude information of the object's wavefield. It enables single-shot measurements of 3D objects at coherent X-ray sources. As the ratio of longitudinal resolution over transverse resolution scales proportional to the diameter of the reference beam aperture over the X-ray wavelength, we expect the approach to be particularly useful in the extreme ultraviolet and soft-X-ray regime.

Exploration of magnetic fluctuations in PdFe films

We investigated magnetic phase transitions, magnetic anisotropy, and magnetic domains in Pd1-xFex alloys with different Fe concentrations x = 2.2-7.2%. The Curie temperature depends linearly on the Fe concentration in the regime studied. The magnetization is dominantly in-plane with a small out-of-plane remanent contribution. Resonant magnetic small angle scattering with circularly polarized x-rays tuned to the L3 resonance edge of Fe revealed a small angle scattering ring corresponding to magnetic domain fluctuations on a length scale of 100 nm. These fluctuations are isotropically distributed in the film plane and appear to have an out-of-plane component. On increasing the transverse coherence of the incident beam, the scattering ring decomposes in a speckle pattern, indicative of magnetic correlations on a length scale smaller than the x-ray coherence length of about 4 μm.

Breakdown of the x-ray resonant magnetic scattering signal during intense pulses of extreme ultraviolet free-electron-laser radiation

We present results of single-shot resonant magnetic scattering experiments of Co/Pt multilayer systems using 100 fs long ultraintense pulses from an extreme ultraviolet (XUV) free-electron laser. An x-ray-induced breakdown of the resonant magnetic scattering channel during the pulse duration is observed at fluences of 5  J/cm(2). Simultaneously, the speckle contrast of the high-fluence scattering pattern is significantly reduced. We performed simulations of the nonequilibrium evolution of the Co/Pt multilayer system during the XUV pulse duration. We find that the electronic state of the sample is strongly perturbed during the first few femtoseconds of exposure leading to an ultrafast quenching of the resonant magnetic scattering mechanism.

Ultrafast optical demagnetization manipulates nanoscale spin structure in domain walls

During ultrafast demagnetization of a magnetically ordered solid, angular momentum has to be transferred between the spins, electrons, and phonons in the system on femto- and picosecond timescales. Although the intrinsic spin-transfer mechanisms are intensely debated, additional extrinsic mechanisms arising due to nanoscale heterogeneity have only recently entered the discussion. Here we use femtosecond X-ray pulses from a free-electron laser to study thin film samples with magnetic domain patterns. We observe an infrared-pump-induced change of the spin structure within the domain walls on the sub-picosecond timescale. This domain-topography-dependent contribution connects the intrinsic demagnetization process in each domain with spin-transport processes across the domain walls, demonstrating the importance of spin-dependent electron transport between differently magnetized regions as an ultrafast demagnetization channel. This pathway exists independent from structural inhomogeneities such as chemical interfaces, and gives rise to an ultrafast spatially varying response to optical pump pulses.

Endstation for ultrafast magnetic scattering experiments at the free-electron laser in Hamburg

An endstation for pump-probe small-angle X-ray scattering (SAXS) experiments at the free-electron laser in Hamburg (FLASH) is presented. The endstation houses a solid-state absorber, optical incoupling for pump-probe experiments, time zero measurement, sample chamber, and detection unit. It can be used at all FLASH beamlines in the whole photon energy range offered by FLASH. The capabilities of the setup are demonstrated by showing the results of resonant magnetic SAXS measurements on cobalt-platinum multilayer samples grown on freestanding Si(3)N(4) membranes and pump-laser-induced grid structures in multilayer samples.

Holographically aided iterative phase retrieval

Fourier transform holography (FTH) is a noise-resistant imaging technique which allows for nanometer spatial resolution x-ray imaging, where the inclusion of a small reference scattering object provides the otherwise missing phase information. With FTH, one normally requires a considerable distance between the sample and the reference to ensure spatial separation of the reconstruction and its autocorrelation. We demonstrate however that this requirement can be omitted at the small cost of iteratively separating the reconstruction and autocorrelation. In doing so, the photon efficiency of FTH can be increased due to a smaller illumination area, and we show how the presence of the reference prevents the non-uniqueness problems often encountered with plane-wave iterative phase retrieval. The method was tested on a cobalt/platinum multilayer exhibiting out of plane magnetized domains, where the magnetic circular dichroism effect was used to image the magnetic domains at the cobalt L₃-edge at 780eV.

Osteopontin deficiency protects against obesity-induced hepatic steatosis and attenuates glucose production in mice

AIMS/HYPOTHESIS

Obesity is strongly associated with the development of non-alcoholic fatty liver disease (NAFLD). The cytokine osteopontin (OPN) was recently shown to be involved in obesity-induced adipose tissue inflammation and reduced insulin response. Accumulating evidence links OPN to the pathogenesis of NAFLD. Here we aimed to identify the role of OPN in obesity-associated hepatic steatosis and impaired hepatic glucose metabolism.

METHODS

Wild-type (WT) and Opn (also known as Spp1) knockout (Opn (-/-)) mice were fed a high-fat or low-fat diet to study OPN effects in obesity-driven hepatic alterations.

RESULTS

We show that genetic OPN deficiency protected from obesity-induced hepatic steatosis, at least in part, by downregulating hepatic triacylglycerol synthesis. Conversely, absence of OPN promoted fat storage in adipose tissue thereby preventing the obesity-induced shift to ectopic fat accumulation in the liver. Euglycaemic-hyperinsulinaemic clamp studies revealed that insulin resistance and excess hepatic glucose production in obesity were significantly attenuated in Opn (-/-) mice. OPN deficiency markedly improved hepatic insulin signalling as shown by enhanced insulin receptor substrate-2 phosphorylation and prevented upregulation of the major hepatic transcription factor Forkhead box O1 and its gluconeogenic target genes. In addition, obesity-driven hepatic inflammation and macrophage accumulation was blocked by OPN deficiency.

CONCLUSIONS/INTERPRETATION

Our data strongly emphasise OPN as mediator of obesity-associated hepatic alterations including steatosis, inflammation, insulin resistance and excess gluconeogenesis. Targeting OPN action could therefore provide a novel therapeutic strategy to prevent obesity-related complications such as NAFLD and type 2 diabetes.

Rapid vinculin exchange dynamics at focal adhesions in primary osteoblasts following shear flow stimulation

The adaptor protein vinculin plays a key position in the formation of focal adhesions and regulates cell attachment. To study the turnover of vinculin in bone-derived cells, we expressed green fluorescent protein-tagged vinculin in primary bovine osteoblasts and examined the appearance of focal adhesions in cells exposed to laminar shear flow. Already 20 sec after application of shear stress fluorescently labelled focal adhesions became visible as small flashing dots at the periphery of cells. The number of newly formed focal adhesions per individual cell increased continuously over approximately 300 sec and then remained relatively stable. The assembly of focal adhesions in shear stress-stimulated osteoblasts was accompanied by a transient rise in intracellular calcium levels. The mean assembly time of an individual focal adhesion plaque was 32.2+/-2.2 sec and the mean disassembly time was 60.5+/-6.0 sec. The recruitment of vinculin to nascent focal adhesions was in the same range as the recovery half-life of GFP-vinculin at stable focal adhesions (13.0+/-2.0 sec). These data show that accumulation of GFP-vinculin in newly formed focal adhesions and its exchange from pre-existing, mature plaques are both rapid processes that occur in mechanically stimulated osteoblasts within less than one minute.

Coherent-pulse 2D crystallography using a free-electron laser x-ray source

Coherent diffractive imaging for the reconstruction of a two-dimensional (2D) finite crystal structure with a single pulse train of free-electron laser radiation at 7.97 nm wavelength is demonstrated. This measurement shows an advance on traditional coherent imaging techniques by applying it to a periodic structure. It is also significant that this approach paves the way for the imaging of the class of specimens which readily form 2D, but not three-dimensional crystals. We show that the structure is reconstructed to the detected resolution, given an adequate signal-to-noise ratio.

[Diffuse dermal angiomatosis]

Diffuse dermal angiomatosis (DDA) is a benign, acquired vascular proliferation characterized by painful, poorly circumscribed, livid-erythematous plaques with frequent central ulceration. The clinical features are reminiscent of reactive angioendotheliomatosis or embolia cutis medicamentosa. Histologically, a dense diffuse network of regular capillary vessels throughout the dermis is seen. Endothelial atypia, atypical mitoses or signs of vasculitis are missing. A 43-year-old woman developed a bizarre brownish-livid rapidly growing lesion of DDA 8 centimeters above a surgical scar, shortly after removal of 20 kilograms of fatty tissue from the lower abdominal wall. DDA regressed spontaneously within 12 weeks, and has not recurred over 4 years of follow-up.

Ocular changes in mucopolysaccharidosis IV A (Morquio A syndrome) and long-term results of perforating keratoplasty

BACKGROUND

The mucopolysaccharidoses (MPS) are an inhomogeneous group of disorders of errors in the carbohydrate metabolism with severe ocular involvement (corneal opacification, retinal degeneration, optic atrophy).

PATIENT PRESENTATION

We report on a boy aged 12 years, with Morquio A (MPS IV A) syndrome. Ocular findings: progressive pseudoexophthalmus due to shallow orbits, increasing corneal stromal clouding, intermittent dissociated manifest nystagmus of the left eye, nyctalopia. Visual acuity OD cc = 0.16, OS cc = 0.05. Electrophysiology: changes suggesting a symptomatic tapetoretinal degeneration and optic atrophy. TREATMENT AND COURSE OF DISEASE: OS: perforating keratoplasty. Postoperative improvement of visual acuity to 0.25 for nearly a year, followed by progressive reopacification of the corneal graft. Both eyes: progressive signs of tapetoretinal degeneration and optic atrophy. Visual acuity now reduced to OD 0.05, OS 0.1.

CONCLUSIONS

Success of a keratoplasty is limited by (1) reopacification of the cornea, (2) visual impairment due to (a) retinal degeneration and (b) optic atrophy. The indication for perforating keratoplasty has to be thought about very carefully in these multimorbid patients. In our patient, beside progressive visual impairment there is a progressive deafness which dominates his social and school life. Attending school is severely complicated by the double handicap. Perforating keratoplasty enabled the boy to attend a school for physically handicapped without a special low-vision care for another year. Progressive visual loss without further treatment options now renders optical and electronic low-vision aids necessary. Although the time of improved visual acuity lasted less than a year, we think patients with a life expectancy of less than 20 years should have every possible improvement of their situation - even if it does not last permanently. We therefore propose perforating keratoplasty in spite of insufficient long-term results.

[Screening for amblyopia, strabismus and refractive abnormalities in 1,030 kindergarten children]

BACKGROUND

There are controversies concerning the necessity of pre-school vision screening.

AIM OF THE STUDY

evaluation of the prevalence of pathologic ophthalmologic findings in kindergarten children.

MATERIALS AND METHODS

1030 families were offered a vision screening. Of these, a total of 948 children, aged 3 to 6 years, voluntarily underwent a screening for strabismus, amblyopia and refractive anomalies. The examination was performed in the kindergarten in the absence of the parents. METHODS OF EXAMINATION: A questionnaire concerning general and ophthalmologic history of the child and of the family was evaluated. Visual acuity, cover-uncover-test, Lang-stereotest, retinoscopy, ophthalmoscopy (undilated pupils) were performed and the glasses were evaluated.

RESULTS

The screening was highly accepted by the parents and 92% of the families (n = 948) took part. The compliance of the children was very good. A total of 38.7% (n = 381) of the children showed one or more abnormal parameters. 21.4% (n = 229) showed a reduced visual acuity. Strabismus was found in 3.7%. Half of the children with abnormal findings already had had a vision screening, but only 25% had received ophthalmologic treatment. Of those who possessed glasses, 25% came without them, and another 25% had a reduced visual acuity even with their glasses. The main problems were many false-positive results and high costs.

CONCLUSIONS

Ophthalmologic and orthoptic screening in kindergarten is technically easy and conclusive in experienced hands. Ideas to reduce costs and to avoid overreferrals are an age-related lowering of the visual acuity limit and a rescreening of suspected children in a screening-setting a second time before sending them to an ophthalmologist. Another possibility to reduce costs would be to perform examinations not by ophthalmologists but by "screening-orthoptists" who should be trained in retinoscopy and ophthalmoscopy.

[Eye and general illnesses in the public school for blind and visually handicapped students in Saarland. Developments in the last 20 years]

BACKGROUND

The aim of the study was the evaluation of how ophthalmological diagnoses and the proportion of multiply handicapped children has changed within the last 20 years at a state school for visually handicapped and blind children.

PATIENTS AND METHODS

A profile investigation was conducted on all 105 children at the Landesschule für Blinde und Sehbehinderte des Saarlandes and compared to the results of an examination from 1975.

RESULTS

The predominant ophthalmological diagnoses were: optic atrophy (17.5%), ocular albinism (11.9%), scar-stage IV and V of retinopathy of prematurity (11.1%), as well as tapetoretinal dystrophies with related syndromes (8.7%) and myopia magna (7.9%). Blind: 10.3% (1975: 36.4%); visually handicapped: 47.1% (1975: 49.2%); multiply handicapped: 42.5% (1975: 14.4%).

CONCLUSIONS

(1) The diseases that dominated in earlier years in schools for the visually handicapped have become rare (cataract, aphakia, buphthalmia, macular dystrophy--all less than 5%); (2) the proportion of completely blind pupils has become much smaller; (3) there is an increasing tendency to educate visually handicapped pupils in regular schools with integrative aids; (4) there is also an increasing proportion of multiply handicapped children (school and kindergarten: 42%, early patronage 74%).

[Comparison between local and systemic administration of cyclosporin A on the effective level in conjunctiva, aqueous humor and serum]

Cyclosporine is an important tool for the therapy of immunological diseases of the cornea and conjunctiva, as well as the treatment of patients with high-risk corneal grafts. However, potentially severe systemic side effects are disadvantageous. The purpose of our study was to determine if topical ocular application leads to about the same concentrations in ocular tissues as systemic application. Therefore, the concentration of cyclosporine in conjunctiva, aqueous humor and blood was measured by radioimmunoassay in six patients with systemic administration of cyclosporine and ten patients who received one drop of topical cyclosporine 2% four times prior to cataract surgery. All patients with systemic application showed measurable concentrations of cyclosporine in blood, as did four patients in the group receiving topical cyclosporine. There was no significant difference between both groups concerning cyclosporine concentration in aqueous humor. The level of cyclosporine in the conjunctiva was significantly higher after topical application (P < 0.02). In conclusion, therapy with cyclosporine eye drops results in levels in the conjunctiva and aqueous humor that are comparable to or even higher than those after systemic application if the last application was no more than 18h prior to the measurement. Therefore, topical ocular application of cyclosporine, which reduces or eliminates the drug's systemic side effects, can be used to induce local immunosuppressive activity, particularly in the treatment of superficial immunological diseases and after limbal allograft transplantation.

[Goniotrepanation combined with sinus surgery as a transitional measure in spontaneous carotid artery-cavernous sinus fistulas]

Two patients with spontaneous, angiographically proven fistulas showed progressive ocular symptoms which precluded waiting for spontaneous occlusion of the fistulas. On the other hand, endovascular therapy of the carotid-cavernous fistulas was not possible because the arterial supply of the fistulas came from both internal carotids. Therefore filtering surgery was performed in the affected eyes. Postoperatively, intraocular pressure decreased to normal values in both patients and the symptoms resolved. The visual acuity increased in one patient and remained the same in the other. In conclusion, filtering surgery is an important therapeutic tool to preserve visual function in eyes with carotid-cavernous fistulas that display progressive ocular symptoms but cannot be treated by embolization.

[Prognosis of intralenticular lead foreign bodies]

BACKGROUND

The prognosis of intraocular foreign bodies consisting of lead remains controversial. While experiments have shown that infected lead becomes sterile when fired from rifles, both the total absence as well as presence of severe inflammation have been observed following perforating injuries with lead. Furthermore, alterations of the ERG have been described in experimental settings. This case report is presented in order to clarify the long term prognosis of intralenticular lead particles.

PATIENT AND METHOD

The 69-year-old patient suffered from a bilateral perforating injury caused by a bullet during World War II (1942). The right lens was extracted due to a secondary cataract several weeks following the injury. The left lens remained clear despite a paracentrally located metallic foreign body. The patient underwent extracapsular cataract extraction in 1992 because of an opacity of the posterior capsule which was well separated from the foreign body. Preoperatively the ERG was normal. An energy dispersive X-ray microanalysis in a scanning electron microscope was performed in order to determine the chemical composition of the foreign body, and X-ray diffraction with a Gandolphi camera was used for its structural characterisation. The foreign body consists of lead. However, its surface is probably altered to lead oxide, hydroxide or carbonate, which hindered further reaction of the lead. Calcium phosphate was deposited on the walls of the foreign body.

CONCLUSION

Our report shows that lead in the lens remains inert for several decades and does not cause alterations in the ERG. Therefore, intralenticular lead outside of the optical axis may be left in situ unless a secondary cataract develops.

[The staging diagnosis of Hodgkin's disease. A comparison of laparotomy and noninvasive methods]

The diagnostic efficiency of modern noninvasive methods more and more puts into question the need for exploratory laparotomy to determine the stage of Hodgkin's disease. In 208 patients (122 men and 86 women; mean age 29 [14-62] years) pre- and postoperative findings as to stage of the abdominal disease were compared. All patients had first been examined by ultrasound and computed tomography, followed by laparotomy with splenectomy. Findings of lymphography were available for 171 patients. Gross and microscopic examination of the tissues obtained by splenectomy and lymphadenectomy, as well as liver biopsy provided different stages from the preoperative ones, which in 46 had been false-negative, and in 16 false-positive. Spleen weight and involvement of the spleen with Hodgkin infiltration correlated only weakly with one another. In 38 of 41 patients with parapancreatic and splenohilar lymphnode involvement the spleen was also affected. These results indicate that regarding the stage of Hodgkin's disease, noninvasive methods so far do not achieve the validity of pathological examination obtained at exploratory laparotomy with splenectomy.

Congenital glaucoma in cutis marmorata teleangiectatica congenita

A case of congenital glaucoma in cutis marmorata teleangiectatica congenita (CMTC, van Lohuizen syndrome) is described. The cutaneous anomaly and heterochromia iridium were noticed at birth. Brown discoloration of one iris was due to iris anterior layer dysplasia, resulting in unilateral glaucoma. Two trabeculotomies were performed until persistent normalization of intraocular pressure could be achieved. The possibility of a genetic basis and hereditary condition of CMTC and its association with congenital glaucoma is discussed. Patients with CMTC should regularly undergo ophthalmological follow-up to rule out development of glaucoma.

Data attrition in follow-up studies of alcoholics

Alcoholics who responded to posttreatment follow-up evaluation showed more improvement than those wh did not respond. Thus nonresponders may bias follow-up research tht does not account for missing data. Several procedures are outlined to increase follow-up return.