Seroprevalence of tick-borne encephalitis virus and vaccination coverage of tick-borne encephalitis, Sweden, 2018 to 2019

BackgroundIn Sweden, information on seroprevalence of tick-borne encephalitis virus (TBEV) in the population, including vaccination coverage and infection, is scattered. This is largely due to the absence of a national tick-borne encephalitis (TBE) vaccination registry, scarcity of previous serological studies and use of serological methods not distinguishing between antibodies induced by vaccination and infection. Furthermore, the number of notified TBE cases in Sweden has continued to increase in recent years despite increased vaccination.AimThe aim was to estimate the TBEV seroprevalence in Sweden.MethodsIn 2018 and 2019, 2,700 serum samples from blood donors in nine Swedish regions were analysed using a serological method that can distinguish antibodies induced by vaccination from antibodies elicited by infection. The regions were chosen to reflect differences in notified TBE incidence.ResultsThe overall seroprevalence varied from 9.7% (95% confidence interval (CI): 6.6-13.6%) to 64.0% (95% CI: 58.3-69.4%) between regions. The proportion of vaccinated individuals ranged from 8.7% (95% CI: 5.8-12.6) to 57.0% (95% CI: 51.2-62.6) and of infected from 1.0% (95% CI: 0.2-3.0) to 7.0% (95% CI: 4.5-10.7). Thus, more than 160,000 and 1,600,000 individuals could have been infected by TBEV and vaccinated against TBE, respectively. The mean manifestation index was 3.1%.ConclusionA difference was observed between low- and high-incidence TBE regions, on the overall TBEV seroprevalence and when separated into vaccinated and infected individuals. The estimated incidence and manifestation index argue that a large proportion of TBEV infections are not diagnosed.

Influenza-A mediated pre-existing immunity levels to SARS-CoV-2 could predict early COVID-19 outbreak dynamics

Susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections is highly variable and could be mediated by a cross-protective pre-immunity. We identified 14 cross-reactive peptides between SARS-CoV-2 and influenza A H1N1, H3N2, and human herpesvirus (HHV)-6A/B with potential relevance. The H1N1 peptide NGVEGF was identical to a peptide in the most critical receptor binding motif in SARS-CoV-2 spike protein that interacts with the angiotensin converting enzyme 2 receptor. About 62%-73% of COVID-19-negative blood donors in Stockholm had antibodies to this peptide in the early pre-vaccination phase of the pandemic. Seasonal flu vaccination enhanced neutralizing capacity to SARS-CoV-2 and T cell immunity to this peptide. Mathematical modeling taking the estimated pre-immunity levels to flu into account could fully predict pre-Omicron SARS-CoV-2 outbreaks in Stockholm and India. This cross-immunity provides mechanistic explanations to the epidemiological observation that influenza vaccination protected people against early SARS-CoV-2 infections and implies that flu-mediated cross-protective immunity significantly dampened the first SARS-CoV-2 outbreaks.

Strict self-isolation did not protect Swedish cancer patients on active treatment from the risk of becoming seropositive for SARS-CoV-2

BACKGROUND

Swedish recommendations to reduce the risk of COVID-19 relied on each citizen's own sense of responsibility rather than mandatory lockdowns. We studied how COVID-19-related self-isolation and anxiety correlated to SARS-CoV-2 seropositivity and PCR-positivity in patients with active cancer treatment.

METHODS

In a longitudinal cohort study at Uppsala University Hospital patients and cancer personnel were included between April 1st 2020 to August 1st 2020. Serological testing for SARS-CoV-2 was done every 8-12-weeks until 30 March 2021. Patients completed a survey at inclusion regarding self-reported COVID-19-related anxiety and self-isolation.

RESULTS

A total of 622 patients [n = 475 with solid malignancies (SM), n = 147 with haematological malignancies (HM)], and 358 healthcare personnel were included. The seropositivity rate was lower for patients than for personnel; 10.5% for SM patients, 6.8% for HM patients, and 16.2% for personnel (p = 0.005). Strict adherence to self-isolation guidelines was reported by 54% of patients but was not associated with a lower risk of becoming seropositive [OR = 1.4 (0.8-2.5), p = 0.2]. High anxiety was expressed by 32% of patients, more often by SM patients than HM patients (34% vs 25% [OR = 1.6 (1.1-2.5, p = 0.03)]). Female gender [OR = 3.5 (2.4-5.2), p < 0.001] and being born outside of Europe [OR = 2.9 (1.4-6.4), p = 0.007] were both associated with high anxiety. Patients reporting high anxiety became seropositive to a similar degree as those with low anxiety [OR = 0.7 (0.3-1.2), p = 0.2]. HM patients with PCR-positive COVID-19 were more likely than SM patients to require oxygen therapy, including non-invasive ventilation/intubation (69% vs. 26%, p = 0.005).

CONCLUSION

For Swedish patients on active cancer treatment, high self-assessed COVID-19-related anxiety or strict adherence to self-isolation guidelines were not associated with a lower risk of COVID-19. Patients with HM were less likely to develop serological antibody response after COVID-19 and were more likely to require advanced hospital care, but expressed less COVID-19-related anxiety than patients with SM.

Reduced Binding between Omicron B.1.1.529 and the Human ACE2 Receptor in a Surrogate Virus Neutralization Test for SARS-CoV-2

The current gold standard assay for detecting neutralizing antibodies (NAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the conventional virus neutralization test (cVNT), which requires infectious virus and a biosafety level 3 laboratory. Here, we report the development of a SARS-CoV-2 surrogate virus neutralization test (sVNT) that, with Luminex technology, detects NAbs. The assay was designed to mimic the virus-host interaction and is based on antibody blockage between the human angiotensin-converting enzyme 2 (hACE2) receptor and the spike (S) protein of the Wuhan, Delta, and Omicron (B.1.1.529) variants of SARS-CoV-2. The sVNT proved to have a 100% correlation with a SARS-CoV-2 cVNT regarding qualitative results. Binding between the hACE2 receptor and the S1 domain of the B.1.1.529 lineage of the Omicron variant was not observed in the assay but between the receptor and an S1 + S2 trimer and the receptor binding domain (RBD) in a reduced manner, suggesting less efficient receptor binding for the B.1.1.529 Omicron variant. The results indicate that the SARS-CoV-2 sVNT is a suitable tool for both the research community and the public health service, as it may serve as an efficient diagnostic alternative to the cVNT.

The Biological and Ecological Features of Northbound Migratory Birds, Ticks, and Tick-Borne Microorganisms in the African-Western Palearctic

Identifying the species that act as hosts, vectors, and vehicles of vector-borne pathogens is vital for revealing the transmission cycles, dispersal mechanisms, and establishment of vector-borne pathogens in nature. Ticks are common vectors for pathogens causing human and animal diseases, and they transmit a greater variety of pathogenic agents than any other arthropod vector group. Ticks depend on the movements by their vertebrate hosts for their dispersal, and tick species with long feeding periods are more likely to be transported over long distances. Wild birds are commonly parasitized by ticks, and their migration patterns enable the long-distance range expansion of ticks. The African-Palearctic migration system is one of the world's largest migrations systems. African-Western Palearctic birds create natural links between the African, European, and Asian continents when they migrate biannually between breeding grounds in the Palearctic and wintering grounds in Africa and thereby connect different biomes. Climate is an important geographical determinant of ticks, and with global warming, the distribution range and abundance of ticks in the Western Palearctic may increase. The introduction of exotic ticks and their microorganisms into the Western Palearctic via avian vehicles might therefore pose a greater risk for the public and animal health in the future.

COVID-19 seroprevalence and clinical picture in Swedish pediatric oncology and hematology patients

BACKGROUND

Children develop symptomatic coronavirus disease 2019 (COVID-19) more rarely than adults upon infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pediatric oncology and hematology patients may be at increased risk of severe COVID-19 due to their underlying disease or treatment. We investigated COVID-19 and seroprevalence of anti-SARS-CoV-2 antibodies, respectively, in a Swedish cohort of pediatric oncology and hematology patients.

PROCEDURE

Patients (n = 136) were recruited between June 2020 and September 2021 at Uppsala University Children's Hospital, Sweden. Up to six consecutive blood samples per patient were analyzed for wild-type anti-S1 IgM and IgG antibodies (including after vaccination, n = 4). Clinical data on COVID-19 (including polymerase chain reaction [PCR] test results) were collected from electronic medical records. A questionnaire was completed at recruitment.

RESULTS

A cumulative seroprevalence (IgM and IgG) of 33% (45/136 patients, 95% confidence interval: 25%-41%) was observed in this patient cohort, of whom 66% (90/136 patients) were under severe immunosuppressive treatment during the study period. Increasing patient age (p = .037) and PCR test results (p < .002) were associated with seropositivity in nonvaccinated cases. Most seropositive, nonvaccinated cases (32/43, 74%) were never PCR-verified for SARS-CoV-2 infection. Of the 13 patients with PCR-verified infection, nine (69%) reported mild disease. A majority (63%) reported continued school attendance during the pandemic.

CONCLUSIONS

Swedish pediatric oncology and hematology patients developed antibodies against SARS-CoV-2, despite their diagnosis and/or treatment, and the observed seroprevalence was similar to that in national pediatric outpatients. PCR-verified cases underestimate the true incidence of COVID-19 in this patient cohort.

Association between guilds of birds in the African-Western Palaearctic region and the tick species Hyalomma rufipes, one of the main vectors of Crimean-Congo hemorrhagic fever virus

Introduction

The ecology of the vertebrate host contributes to the geographical range expansion of ticks. In this study, we investigated which tick taxa that infest and are dispersed by birds along African-Western Palaearctic flyways during northward migration, and whether bird ecology was associated with tick taxa.

Materials and methods

Ticks were collected from birds trapped at bird observatories in Spain, Italy, Greece, and Israel during the spring migration of 2014 and 2015, using mist nets. The tick-infested bird species were classified into guilds, using different combinations of the variables: migration distance, wintering region, foraging behaviour, and winter habitat. Ticks were molecularly determined to genus and species level by sequencing fragments of the 12S ribosomal DNA (rDNA) gene and by phylogenetic inference, using the Maximum Likelihood algorithm. Data were analysed using descriptive measures, graphs, Chi2 tests, the Tukey-Kramer test, and a parametric linear model (generalized linear model) in order to analyse and adjust for characteristics in the bird guilds and their relationship to collected tick taxa.

Results

Most (84.2%) of the 10,209 trapped birds were long-distance migrants, of which 2.4% were infested by ticks. The most common tick species was Hyalomma rufipes (77.7%; 447/575), a known vector and reservoir of Crimean-Congo hemorrhagic fever virus. Bird guilds containing only long-distance migrants with wintering areas in Africa were associated with the tick species H. rufipes (p < 0.0001). Furthermore, bird winter habitat was associated with H. rufipes (p = 0.003); with bird species overwintering in open habitat (p = 0.014) and wetlands (p = 0.046) having significantly more H. rufipes as compared to birds with a winter habitat comprising forest and shrubs (p = 0.82).

Conclusions

With climate change, the likelihood of establishment of permanent Hyalomma populations in central and northern Europe is increasing. Thus, surveillance programs for monitoring the risk of introduction and establishment of H. rufipes in the Western-Palaearctic should be established. Our study suggests that migratory bird species wintering in African open habitats and wetlands are good candidates for monitoring potential introduction.

Evaluation of Production Lots of a Rapid Point-of-Care Lateral Flow Serological Test Intended for Identification of IgM and IgG against the N-Terminal Part of the Spike Protein (S1) of SARS-CoV-2

The potential of rapid point-of-care (POC) tests has been subject of doubt due to an eventual risk of production errors. The aim was therefore to evaluate the two separate production lots of a commercial POC lateral flow test, intended for the detection of IgM and IgG against the SARS-CoV-2 spike protein (S1). Control samples consisted of serum from individuals with confirmed SARS-CoV-2 infection and pre-COVID-19 negative sera gathered from a biobank. The presence of anti-S1 IgM/IgG in the sera was verified by an in-house Luminex-based serological assay (COVID-19 SIA). One hundred samples were verified as positive for anti-S1 IgG and 74 for anti-S1 IgM. Two hundred samples were verified as negative for anti-S1 IgM/IgG. For the two lots of the POC-test, the sensitivities were 93.2% and 87.8% for IgM and 93.0% and 100% for IgG. The specificities were 100% for IgM and 99.5% for IgG. The positive predictive value was 100% for IgM and 98.9% and 99.0% for IgG. The negative predictive value was 97.6% and 95.7% for IgM, and 96.6% and 100% for IgG. The evaluated POC-test is suitable to assess anti-SARS-CoV-2 S1 IgM and IgG, as a measure of previous virus exposure on an individual level. The external validation of separate lots of rapid POC-tests is encouraged to ensure high sensitivity before market introduction.

Diagnostic Potential of a Luminex-Based Coronavirus Disease 2019 Suspension Immunoassay (COVID-19 SIA) for the Detection of Antibodies against SARS-CoV-2

Due to the current, rapidly increasing Coronavirus disease 2019 (COVID-19) pandemic, efficient and highly specific diagnostic methods are needed. The receptor-binding part of the spike (S) protein, S1, has been suggested to be highly virus-specific; it does not cross-react with antibodies against other coronaviruses. Three recombinant partial S proteins of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) expressed in mammalian or baculovirus-insect cells were evaluated as antigens in a Luminex-based suspension immunoassay (SIA). The best performing antigen (S1; amino acids 16-685) was selected and further evaluated by serum samples from 76 Swedish patients or convalescents with COVID-19 (previously PCR and/or serologically confirmed), 200 pre-COVID-19 individuals (180 blood donors and 20 infants), and 10 patients with acute Epstein-Barr virus infection. All 76 positive samples showed detectable antibodies to S1, while none of the 210 negative controls gave a false positive antibody reaction. We further compared the COVID-19 SIA with a commercially available enzyme immunoassay and a previously evaluated COVID-19 rapid antibody test. The results revealed an overall assay sensitivity of 100%, a specificity of 100% for both IgM and IgG, a quantitative ability at concentrations up to 25 BAU/mL, and a better performance as compared to the commercial assays, suggesting the COVID-19 SIA as a most valuable tool for efficient laboratory-based serology.

Presymptomatic viral shedding and infective ability of SARS-CoV-2; a case report

Possible pre- or asymptomatic transmission has been reported, both from SARS-CoV and from MERS-CoV outbreaks, although this appears to be uncommon. In contrast, during the COVID-19 pandemic, an increasing number of studies and case reports indicate that pre- or asymptomatic transmission of SARS-CoV-2 is not only possible but also occurs frequently. We report repeated rRT-PCR detection of SARS-CoV-2 in a health care worker and demonstrate infective ability up to three days prior to mild COVID-19 symptoms. rRT-PCR indicated high viral levels approximately three days after exposure. Viral samples collected one and three days prior to symptoms exhibited infectivity on Vero E6 cells, confirmed by detection of double-stranded RNA by immunofluorescence, assessment of cytopathic effect (CPE) and rRT-PCR. SARS-CoV-2 specific IgM and IgG antibodies were detected by day 9 and 15, respectively, after symptom onset. We propose that this provides evidence for potential early presymptomatic transmission of SARS-CoV-2 and that infectivity may be manifest shortly after exposure.

Presymptomatic viral shedding and infective ability of SARS-CoV-2; a case report

Possible pre- or asymptomatic transmission has been reported, both from SARS-CoV and from MERS-CoV outbreaks, although this appears to be uncommon. In contrast, during the COVID-19 pandemic, an increasing number of studies and case reports indicate that pre- or asymptomatic transmission of SARS-CoV-2 is not only possible but also occurs frequently. We report repeated rRT-PCR detection of SARS-CoV-2 in a health care worker and demonstrate infective ability up to three days prior to mild COVID-19 symptoms. rRT-PCR indicated high viral levels approximately three days after exposure. Viral samples collected one and three days prior to symptoms exhibited infectivity on Vero E6 cells, confirmed by detection of double-stranded RNA by immunofluorescence, assessment of cytopathic effect (CPE) and rRT-PCR. SARS-CoV-2 specific IgM and IgG antibodies were detected by day 9 and 15, respectively, after symptom onset. We propose that this provides evidence for potential early presymptomatic transmission of SARS-CoV-2 and that infectivity may be manifest shortly after exposure.

Long-distance airborne dispersal of SARS-CoV-2 in COVID-19 wards

Evidence suggests that SARS-CoV-2, as well as other coronaviruses, can be dispersed and potentially transmitted by aerosols directly or via ventilation systems. We therefore investigated ventilation openings in one COVID-19 ward and central ducts that expel indoor air from three COVID-19 wards at Uppsala University Hospital, Sweden, during April and May 2020. Swab samples were taken from individual ceiling ventilation openings and surfaces in central ducts. Samples were subsequently subjected to rRT-PCR targeting the N and E genes of SARS-CoV-2. Central ventilation HEPA filters, located several stories above the wards, were removed and portions analyzed in the same manner. In two subsequent samplings, SARS-CoV-2 N and E genes were detected in seven and four out of 19 room vents, respectively. Central ventilation HEPA exhaust filters from the ward were found positive for both genes in three samples. Corresponding filters from two other, adjacent COVID-19 wards were also found positive. Infective ability of the samples was assessed by inoculation of susceptible cell cultures but could not be determined in these experiments. Detection of SARS-CoV-2 in central ventilation systems, distant from patient areas, indicate that virus can be transported long distances and that droplet transmission alone cannot reasonably explain this, especially considering the relatively low air change rates in these wards. Airborne transmission of SARS-CoV-2 must be taken into consideration for preventive measures.

High seroprevalence of SARS-CoV-2 in elderly care employees in Sweden

The COVID-19 pandemic is growing and spread in the Swedish elderly care system during April 2020. The increasing number of employees on sick-leave due to COVID-19 created severe logistic problems. Some elderly care homes therefore started to screen their personnel to secure the safety of the elderly and to avoid unnecessary quarantine of potentially immune employees.

Secondary data from a screening with a COVID-19 rapid test for detection of SARS-CoV-2-specific IgM and IgG of 1,005 employees in 22 elderly care homes in Stockholm, Sweden, were analyzed. Seropositive employees were found in 21 out of the 22 care homes. In total, 23% (231/1,005) of the employees tested positive for antibodies against SARS-CoV-2, and 14.3% (144/1,005) were found positive for IgM (either alone or combined with IgG), indicating recent or present infection. Of those that tested seropositive, 46.5% did not report any clinical symptoms, indicating pre- or asymptomatic infections. Reported symptoms with the highest correlation with seropositivity were fever and loss of smell and taste.

These results suggest that antibody testing of employees in elderly care homes is valuable for surveillance of disease development and a crucial screening tool in the effort to decrease the death toll in this pandemic.

The absence of the drhm gene is not a marker for human-pathogenicity in European Anaplasma phagocytophilum strains

BACKGROUND

Anaplasma phagocytophilum is a Gram-negative obligate intracellular bacterium that replicates in neutrophil granulocytes. It is transmitted by ticks of the Ixodes ricinus complex and causes febrile illness in humans and animals. The geographical distribution of A. phagocytophilum spans the Americas, Europe, Africa and Asia. However, human disease predominantly occurs in North America but is infrequently reported from Europe and Asia. In North American strains, the absence of the drhm gene has been proposed as marker for pathogenicity in humans whereas no information on the presence or absence of the drhm gene was available for A. phagocytophilum strains circulating in Europe. Therefore, we tested 511 European and 21 North American strains for the presence of drhm and compared the results to two other typing methods: multilocus sequence typing (MLST) and ankA-based typing.

RESULTS

Altogether, 99% (478/484) of the analyzable European and 19% (4/21) of the North American samples from different hosts were drhm-positive. Regarding the strains from human granulocytic anaplasmosis cases, 100% (35/35) of European origin were drhm-positive and 100% (14/14) of North American origin were drhm-negative. Human strains from North America and Europe were both part of MLST cluster 1. North American strains from humans belonged to ankA gene clusters 11 and 12 whereas European strains from humans were found in ankA gene cluster 1. However, the North American ankA gene clusters 11 and 12 were highly identical at the nucleotide level to the European cluster 1 with 97.4% and 95.2% of identity, respectively.

CONCLUSIONS

The absence of the drhm gene in A. phagocytophilum does not seem to be associated with pathogenicity for humans per se, because all 35 European strains of human origin were drhm-positive. The epidemiological differences between North America and Europe concerning the incidence of human A. phagocytophilum infection are not explained by strain divergence based on MLST and ankA gene-based typing.

Evaluation of a COVID-19 IgM and IgG rapid test; an efficient tool for assessment of past exposure to SARS-CoV-2

COVID-19 is the most rapidly growing pandemic in modern time, and the need for serological testing is most urgent. Although the diagnostics of acute patients by RT-PCR is both efficient and specific, we are also crucially in need of serological tools for investigating antibody responses and assessing individual and potential herd immunity. We evaluated a commercially available test developed for rapid (within 15 minutes) detection of SARS-CoV-2-specific IgM and IgG by 29 PCR-confirmed COVID-19 cases and 124 negative controls. The results revealed a sensitivity of 69% and 93.1% for IgM and IgG, respectively, based solely on PCR-positivity due to the absence of a serological gold standard. The assay specificities were shown to be 100% for IgM and 99.2% for IgG. This indicates that the test is suitable for assessing previous virus exposure, although negative results may be unreliable during the first weeks after infection. More detailed studies on antibody responses during and post infection are urgently needed.

A divergent Anaplasma phagocytophilum variant in an Ixodes tick from a migratory bird; Mediterranean basin

Anaplasma phagocytophilum (AP) has vast geographical and host ranges and causes disease in humans and domesticated animals. We investigated the role of northward migratory birds in the dispersal of tick-borne AP in the African-Western Palearctic.

Ticks were collected from northward migratory birds trapped during spring migration of 2010 at two localities in the central Mediterranean Sea. AP DNA was detected by PCR (gltA and 16S rRNA) and variant determination was performed using ankA sequences.

In total, 358 ticks were collected. One of 19 ticks determined as Ixodes was confirmed positive for AP DNA. The tick was collected from a woodchat shrike (Lanius senator senator) trapped in Greece, and molecularly determined to belong to the I. ricinus complex and sharing highest (95%) 16S RNA sequence identity to I. gibbosus. The ankA AP sequence exhibited highest similarity to sequences from rodents and shrews (82%) and ruminants (80%). Phylogenetic analyses placed it convincingly outside other clades, suggesting that it represents a novel AP variant.

The divergent Ixodes species harboring a novel AP variant could either indicate an enzootic cycle involving co-evolution with birds, or dissemination from other regions by avian migration. None of the 331 Hyalomma marginatum sensu lato ticks, all immature stages, were positive for AP DNA, lending no evidence for the involvement of Hyalomma ticks transported by birds in the ecology of AP.

Pneumococcal vaccination in lung transplant patients

Introduction: This review analyzes the efficacy of pneumococcal vaccinations in lung transplant patients before and after transplantation.Areas covered: This review addresses the risk for respiratory infections, in particular pneumococcal infections, in lung transplantation patients in the context of immunodeficiency and immunosuppressive medication. Vaccination is recommended to counteract the increased risk of pneumococcal infection, and the relevant guidelines are discussed in this review. The design of specific vaccination schedules is required because of the impaired antibody response in specific patient categories.Expert opinion: Lung transplantation candidates should be vaccinated with pneumococcal vaccines prior to transplantation. Currently, the 23-valent pneumococcal polysaccharide vaccine offers the broadest coverage, but the antibody response should be monitored. New generation pneumococcal conjugate vaccines with equally broad serotype coverage could be used in the future. During the post-transplantation period, the immune status of the patients should be monitored regularly, and vaccination should be repeated when indicated.

Thoracic proportions in children without scoliosis

PURPOSE

Scoliosis is a condition of abnormal growth resulting in 3D deformity of both the spine and thoracic cage. The aim of this study is to use chest radiographs of healthy children to define normal thoracic proportions so as to provide a useful normal reference range against which children with spinal deformity can be compared.

METHODS

Three independent reviewers assessed posteroanterior and lateral chest radiographs of 184 normal children aged between two and 15 years. Duplicate assessments were undertaken by all three raters on 36 of these radiographs. We measured the T1 to T12 length, sternal length, chest depth at T6, chest width at T3, chest width at T6 and maximum chest width. Ratios of thoracic dimensions were calculated to define the normal proportions of the thorax. Inter- and intra-rater variance was estimated for all dimensions and dimension ratios.

RESULTS

The intra-rater and inter-rater reliability was excellent with intra-class-correlation coefficients values > 80% and both intra- and inter-rater coefficients of variance < 9% for all parameters. All measured dimensions of the thorax and spine progressed linearly with respect to age. The mean proportions of T1 to 12 length of the sternal length, chest depth at T6, chest width at T3, chest width at T6 and maximum chest width were 0.5, 0.4, 0.7, 0.9 and 1.0, respectively.

CONCLUSION

It is possible to accurately and reproducibly measure the dimensions of the thoracic cage and spine on plain film radiology. The ratios of T1 to T12 length with respect to sternal length, chest depth at T6, chest width at T3, chest width at T6 and maximum chest remain constant with increasing age. Thoracic dimensions in children progress linearly with increasing age.

LEVEL OF EVIDENCE

V.

Three-dimensional printing of metals for biomedical applications

Three-dimensional (3D) printing technology has received great attention in the past decades in both academia and industry because of its advantages such as customized fabrication, low manufacturing cost, unprecedented capability for complex geometry, and short fabrication period. 3D printing of metals with controllable structures represents a state-of-the-art technology that enables the development of metallic implants for biomedical applications. This review discusses currently existing 3D printing techniques and their applications in developing metallic medical implants and devices. Perspective about the current challenges and future directions for development of this technology is also presented.

Alkhurma Hemorrhagic Fever Virus RNA in Hyalomma rufipes Ticks Infesting Migratory Birds, Europe and Asia Minor

Alkhurma hemorrhagic fever virus RNA was detected in immature Hyalomma rufipes ticks infesting northward migratory birds caught in the North Mediterranean Basin. This finding suggests a role for birds in the ecology of the Alkhurma hemorrhagic fever virus and a potential mechanism for dissemination to novel regions. Increased surveillance is warranted.

Molecular detection and characterization of Brucella species in raw informally marketed milk from Uganda

This study identified and characterized Brucella species in the informal milk chain in Uganda. A total of 324 cattle bulk milk samples were screened for the genus Brucella by real-time PCR with primers targeting the bcsp31 gene and further characterized by the omp25 gene. Of the samples tested, 6.5% were positive for Brucella species. In the omp25 phylogeny, the study sequences were found to form a separate clade within the branch containing B. abortus sequences. The study shows that informally marketed cattle milk in Uganda is a likely risk factor for human brucellosis and confirms that B. abortus is present in the cattle population. This information is important for potential future control measures, such as vaccination of cattle.

Design of Cherenkov bars for the optical part of the time-of-flight detector in Geant4

We present the results of studies devoted to the development and optimization of the optical part of a high precision time-of-flight (TOF) detector for the Large Hadron Collider (LHC). This work was motivated by a proposal to use such a detector in conjunction with a silicon detector to tag and measure protons from interactions of the type p + p → p + X + p, where the two outgoing protons are scattered in the very forward directions. The fast timing detector uses fused silica (quartz) bars that emit Cherenkov radiation as a relativistic particle passes through and the emitted Cherenkov photons are detected by, for instance, a micro-channel plate multi-anode Photomultiplier Tube (MCP-PMT). Several possible designs are implemented in Geant4 and studied for timing optimization as a function of the arrival time, and the number of Cherenkov photons reaching the photo-sensor.

Does iodine gas released from seaweed contribute to dietary iodine intake?

Thyroid hormone levels sufficient for brain development and normal metabolism require a minimal supply of iodine, mainly dietary. Living near the sea may confer advantages for iodine intake. Iodine (I(2)) gas released from seaweeds may, through respiration, supply a significant fraction of daily iodine requirements. Gaseous iodine released over seaweed beds was measured by a new gas chromatography-mass spectrometry (GC-MS)-based method and iodine intake assessed by measuring urinary iodine (UI) excretion. Urine samples were obtained from female schoolchildren living in coastal seaweed rich and low seaweed abundance and inland areas of Ireland. Median I(2) ranged 154-905 pg/L (daytime downwind), with higher values (~1,287 pg/L) on still nights, 1,145-3,132 pg/L (over seaweed). A rough estimate of daily gaseous iodine intake in coastal areas, based upon an arbitrary respiration of 10,000L, ranged from 1 to 20 μg/day. Despite this relatively low potential I(2) intake, UI in populations living near a seaweed hotspot were much higher than in lower abundance seaweed coastal or inland areas (158, 71 and 58 μg/L, respectively). Higher values >150 μg/L were observed in 45.6% of (seaweed rich), 3.6% (lower seaweed), 2.3% (inland)) supporting the hypothesis that iodine intake in coastal regions may be dependent on seaweed abundance rather than proximity to the sea. The findings do not exclude the possibility of a significant role for iodine inhalation in influencing iodine status. Despite lacking iodized salt, coastal communities in seaweed-rich areas can maintain an adequate iodine supply. This observation brings new meaning to the expression "Sea air is good for you!"

Development of computational models for the purpose of conducting individual livestock and premises traceback investigations utilizing National Animal Identification System-compliant data

Many of the efforts surrounding the development of the National Animal Identification System have encompassed the identification of livestock production and handling premises as well as individuals or herds of animals, whereas little effort has been directed toward the ultimate goal of animal traceback within 48 h. A mock data set representative of the Colorado cattle population was created for modeling of cattle traceability. Using this data set, algorithms were developed to complete rapid and accurate traceback and traceforward of animals or premises or both. On July 19, 2005, the Colorado Department of Public Health and Environment, in conjunction with the Colorado Department of Agriculture, conducted a test exercise pertaining to homeland security. The exercise team randomly identified animal number 926,583 (of the 2 million total animals) as a potentially infected animal of interest and requested a traceback of this animal. Traceback was accomplished in 215 s, and 540 primary coresident animals were identified. However, due to animal movements, the number of coresidents (animals exposed, directly or indirectly, to the animal of interest) expanded with coresidency level (level 1 = direct contact; level 2 = direct contact with an animal that had direct contact with the animal of interest; level 3 = direct contact with an animal that had contact with an animal that had direct contact with the animal of interest, etc.) to more than 1.2 million coresidents at level 4, and more than 90% of all animals identified as a coresident at some level. In addition to the coresidency results, the premises containing the coresidents were identified and sorted by the number of coresidents. Because of animal movement, all 19,391 premises included in the data set had coresidents at some level. This exercise demonstrated the capability of the developed algorithms to complete rapid traceback and the complexity of the resulting animal traceback output.

Diffuse basal ganglia or thalamus hyperechogenicity in preterm infants

OBJECTIVE

To determine the incidence and factors associated with diffuse basal ganglia or thalamus hyperechogenicity (BGTH) in preterm infants.

STUDY DESIGN

(1) Review of serial neurosonograms among neonates with gestational age (GA) <34 weeks born at Weiler Hospital during a 21-month period; (2) Color Doppler flow imaging; (3) Case-control study using GA group-matched controls; and (4) Blind reading of CT scans or MRIs in patients with BGTH.

RESULTS

Among 289 infants, 24 (8.3%) had diffuse BGTH. Color Doppler flow imaging was normal in nine patients. The incidence of diffuse BGTH was inversely related to GA (P<0.01). Logistic regression (n=96) showed that diffuse BGTH was significantly associated with requirement of high-frequency oscillation (HFO) (P=0.031), severe intraventricular hemorrhage (IVH) (P=0.004), hypotension requiring vasopressors (P=0.040), hypoglycemia (P=0.031) and male gender (P=0.014). Most patients with diffuse BGTH had normal basal ganglia and thalamus on CT/MRI, one had a hemorrhage, and one had an ischemic infarction.

CONCLUSIONS

In our series, diffuse BGTH occurred in 8.3%, and was associated with factors similar to those previously reported. In contrast, several series have reported almost exclusively linear or punctuate hyperechoic foci, corresponding to hyperechogenicity of the lenticulostriate vessels. Our data provide further evidence to suggest that diffuse BGTH and hyperechogenicity of the lenticulostriate vessels are two different entities. Additional studies are required to determine the long-term significance of diffuse BGTH.

Hormonal regulation of hepatic organic anion transporting polypeptides

Organic anion transporting polypeptides (Oatp) mediate the transport of a wide variety of amphipathic organic substrates. Rat Oatp1b2 and human OATP1B3 are members of a liver-specific subfamily of Oatps/OATPs. We investigated whether prolactin (PRL) and growth hormone (GH) regulated Oatp1b2 and OATP1B3 gene expression via signal transducers and activators of transcription 5 (Stat5). Binding sites for Stat5 transcription factors were located in the promoters of Oatp1b2 and OATP1B3 at -209 to -201 (5'-TTCTGGGAA-3') and -170 to -162 (5'-TTCTGAGAA-3'), respectively. In primary hepatocytes from female and male rats treated with PRL or GH, Oatp1b2 mRNA measured by real-time polymerase chain reaction was significantly induced 2-fold. HepG2 cells were transiently transfected with expression vectors containing Oatp1b2 or OATP1B3 promoter fragments, cDNAs for Stat5a, and the receptors for PRL (PRLR(L)) or GH (GHR), and treated with PRL or GH. PRL and GH induction of Oatp1b2 and OATP1B3 promoter activity required cotransfection of Stat5a and PRLR(L) or GHR. Mutation of the Stat5 binding site in both promoters eliminated hormonal induction. In DNA binding assays, HepG2 cells transfected with cDNAs for Stat5a and PRLR(L) were treated with PRL, and nuclear extracts were probed with a (32)P-labeled oligomer corresponding to -177 to -157 of the OATP1B3 promoter. PRL enhanced the binding of Stat5a to the OATP1B3 promoter and DNA-protein binding was inhibited in competition assays by excess OATP1B3 and Stat5 consensus oligomers but not by mutant Stat5 oligomers. These findings indicate that PRL and GH can regulate Oatp1b2 and OATP1B3 gene expression via the Stat5 signal-transduction pathway.

Molecular basis of perinatal changes in UDP-glucuronosyltransferase activity in maternal rat liver

The molecular basis of perinatal changes occurring in major UDP-glucuronosyltransferase (UGT) family 1 isoforms and in UGT2B1, a relevant isoform belonging to family 2, was analyzed in rat liver. Nonpregnant, pregnant (19-20 days of pregnancy), and two groups of postpartum animals corresponding to early and middle stages of lactation (2-4 and 10-12 days after delivery, respectively) were studied. UGT activity determined in UDP-N-acetylglucosamine-activated microsomes revealed that bilirubin, p-nitrophenol, and ethynylestradiol (17beta-OH and 3-OH) but not androsterone and estrone glucuronidation rates, were decreased in pregnant rats. Decreased enzyme activities returned to control values after delivery. p-Nitrophenol, androsterone, and estrone conjugation rate increased in postpartum rats. Western blot analysis performed with anti-peptide-specific (anti-1A1, 1A5, 1A6, and 2B1) antibodies revealed decreased levels of all family 1 isoforms and UGT2B1 during pregnancy. In postpartum animals, protein level recovered (1A5 and 2B1) or even increased (1A1 and 1A6) with respect to control rats. Northern blot analysis suggested that expression of UGT proteins is down-regulated at a post-translational level during pregnancy and that increased levels of 1A1 and 1A6 observed in postpartum rats were associated to increased mRNA. To establish whether prolactin is involved in up-regulation of UGT1A1 and 1A6 postpartum, ovariectomized rats were treated with 300 microg of ovine prolactin per day for 7 days. The data indicated that prolactin was able to increase expression of UGT1A6 (protein and mRNA) but not 1A1. Thus, prolactin is the likely mediator of the increased expression of UGT1A6 observed in maternal liver postpartum.

Expression of multidrug resistance-associated protein 2 in small intestine from pregnant and postpartum rats

We analyzed the expression of multidrug resistance-associated protein 2 (mrp2) in the small intestine of control female rats and in rats during late pregnancy (19-20 days of pregnancy) and lactation (2-4, 10-14, and 21 days after delivery). Western blot analysis was performed on brush-border membranes prepared from different regions of the small intestine. Expression of mrp2 was maximal in the proximal segments for all experimental groups, was preserved in pregnant rats, and increased by 100% in postpartum rats by late lactation with respect to control animals. Northern blot analysis of mrp2 mRNA revealed a positive correlation with protein levels. Transport of S-glutathione-dinitrophenol (DNP-SG) from the intestinal cell to the lumen was analyzed in the everted intestinal sac model. Secretion of DNP-SG was not altered in pregnant rats but increased in lactating animals by late lactation. Intestinal mrp2 mRNA, protein, and transport activity are increased in lactating rats, suggesting that this may represent an adaptive mechanism to minimize the toxicity of dietary xenobiotics in response to increased postpartum food consumption.

Genitourinary tuberculosis after renal transplantation: report of 3 cases and review

Mycobacterium tuberculosis infection of the genitourinary tract is an uncommon disease in renal transplant recipients and presentation is atypical. Genitourinary tuberculosis is associated with graft rejection, and this diagnosis should be considered for renal transplant recipients with unexplained fever and constitutional symptoms.

Development of an in vitro model for assessing the in vivo stability of lanthanide chelates

An in vitro model was developed to evaluate the in vivo stability of lanthanide polyaminocarboxylate complexes. The ligand-to-metal ratios for the chelates EDTA, CDTA, DTPA, MA-DTPA (monoamide-DTPA) and DOTA with the lanthanides lanthanum, samarium, and lutetium were optimized to achieve > or = 98% complexation yield for the resultant radiolanthanide complexes. The exchange of the radiolanthanides from their EDTA, CDTA, DTPA, MA-DTPA and DOTA complexes with Ca(2+) was determined by in vitro adsorption and in vitro column studies using hydroxyapatite (HA), an in vitro bone model. In vitro serum stability of these radiolanthanide complexes was used as an additional indicator of in vivo stability, although the mechanism of instability in serum will be different than with bone. The in vitro studies were consistent with the expected findings that the smallest lanthanide (Lu) formed the most stable complexes. In vivo studies were done to validate the in vitro model. Biodistribution studies in normal CF-1 mice showed that in vivo stability of the complex (i.e., the more lanthanide remaining in complex form) could be assessed by a combination of the urinary, bone and liver uptake. For example, biodistribution studies demonstrate that high urinary excretion correlated with complex stability, while high liver plus bone uptake correlated with complex instability. The urinary excretion of the EDTA complexes decreased from (177)Lu to (140)La indicating a loss in stability in the direction of (140)La, consistent with the in vitro studies. The more stable a lanthanide complex is, the lower its exchange with HA in vitro will be, and the lower its combined bone plus liver uptake and higher its urinary excretion will be in vivo. This investigation indicates that the in vivo stability can be determined by a screening method that measures the degree of exchange from the lanthanide chelate with hydroxyapatite (HA) and its serum stability.

Differential regulation of hepatic bile salt and organic anion transporters in pregnant and postpartum rats and the role of prolactin

We characterized expression and activity of the bile salt transporters Na(+)/taurocholate (TC) cotransporting polypeptide (Ntcp), and bile salt export pump (Bsep), and the expression of organic anion transporting polypeptides 1 and 2 (Oatp1 and 2) and multidrug resistance associated protein-2 (Mrp2) in pregnancy and throughout lactation in rats. The V(max) for Na(+)/TC cotransport in basolateral liver plasma membrane was increased 1.7-fold in 2 days postpartum relative to control and pregnant rats. This correlated well with an increase in Ntcp messenger RNA (mRNA) and a 2-fold increase in Ntcp protein. Ntcp mRNA remained significantly elevated until 14 days postpartum but had begun to decline by 21 days postpartum. The maximal secretory rate (nmol/min/g liver) for TC in the single pass isolated perfused liver was also increased by 10%, 31%, and 24% at 2, 14, and 21 days postpartum and correlated with increased expression of Ntcp and Bsep mRNA and protein. Infusion of ovine prolactin (oPRL) to ovariectomized rats increased expression of both Ntcp and Bsep mRNA and protein. These data indicate a coordinate increased expression of bile salt transporters postpartum and by PRL. Mrp2 mRNA was stable in pregnancy and postpartum, whereas Mrp2 protein expression decreased significantly in pregnancy, but returned to control levels postpartum. Organic anion transporting polypeptide 2 (Oatp2) mRNA was decreased in pregnancy and increased postpartum, but changes in Oatp2 protein were not significant. Oatp1 mRNA and protein were unchanged in pregnancy and postpartum.

Expression and localization of multidrug resistant protein mrp2 in rat small intestine

The expression of multidrug resistance-associated protein isoform 2 (mrp2), the ATP-dependent export pump that mediates the transport of glucuronic acid-, glutathione-, and sulfate-conjugated derivatives, was studied in rat small intestine. The small intestine was divided into nine equal segments, and mrp2 content was analyzed in homogenate and brush border membrane preparations by Western analysis. mrp2 protein was present mainly in brush border membrane of the proximal segments and gradually decreased from jejunum to the distal ileum. We also analyzed the content of mrp2 in three different populations of proximal enterocytes obtained from the upper and lower villus and the crypt regions. The export pump was mainly expressed in the villus cells and to a lesser degree in the crypt cells of the epithelium. Immunohistochemical analysis performed in duodenum, jejunum, and ileum confirmed in situ the Western blot findings. Analysis of mRNA encoding mrp2 in proximal and distal segments revealed a similar content in both regions, whereas distribution along the villus-crypt axis was similar to the protein gradient. Because conjugating enzymes are distributed similarly to mrp2, we conclude that they may act coordinately to contribute to first-pass metabolism of drugs and other xenobiotics in the proximal small intestine.

Isolation of ethylene-insensitive soybean mutants that are altered in pathogen susceptibility and gene-for-gene disease resistance

Plants commonly respond to pathogen infection by increasing ethylene production, but it is not clear if this ethylene does more to promote disease susceptibility or disease resistance. Ethylene production and/or responsiveness can be altered by genetic manipulation. The present study used mutagenesis to identify soybean (Glycine max L. Merr.) lines with reduced sensitivity to ethylene. Two new genetic loci were identified, Etr1 and Etr2. Mutants were compared with isogenic wild-type parents for their response to different soybean pathogens. Plant lines with reduced ethylene sensitivity developed similar or less-severe disease symptoms in response to virulent Pseudomonas syringae pv glycinea and Phytophthora sojae, but some of the mutants developed similar or more-severe symptoms in response to Septoria glycines and Rhizoctonia solani. Gene-for-gene resistance against P. syringae expressing avrRpt2 remained effective, but Rps1-k-mediated resistance against P. sojae races 4 and 7 was disrupted in the strong ethylene-insensitive etr1-1 mutant. Rps1-k-mediated resistance against P. sojae race 1 remained effective, suggesting that the Rps1-k locus may encode more than one gene for disease resistance. Overall, our results suggest that reduced ethylene sensitivity can be beneficial against some pathogens but deleterious to resistance against other pathogens.

Adenosine triphosphate-dependent transport of estradiol-17beta(beta-D-glucuronide) in membrane vesicles by MDR1 expressed in insect cells

MDR1, an ABC transporter that confers multidrug resistance in tumor cells, is constitutively expressed in normal liver canalicular membrane. Human MDR1-expressing multidrug-resistant cells display increased resistance to estradiol-17beta(beta-D-glucuronide) (E217G). MDR1 substrates/modulators inhibit adenosine triphosphate (ATP)-dependent transport of E217G in the rat canalicular membrane and protect against E217G-mediated cholestasis in isolated perfused rat liver. The present studies were designed to determine if E217G is a substrate for MDR1 using a baculovirus expression system and if other estrogen glucuronides interact with MDR1. ATP-dependent transport of E217G (10 micromol/L) was linear for up to 2 minutes and yielded a rate of 45.6 pmol/min/mg protein in membrane vesicles from Sf9 cells infected with MDR1-baculovirus. This transport was saturable (Km = 62 micromol/L) and occurred into an osmotically sensitive space. ATP-dependent transport of E217G (10 micromol/L) was inhibited 63% by 10 micromol/L daunomycin, but not by 100 micromol/L S-(2,4-dinitrophenyl)glutathione (GS-DNP) (a substrate for canalicular multispecific organic anion transporter [cMOAT]). Glucuronide conjugates of the estrogen D-ring (100 micromol/L), estriol-17beta(beta-D-glucuronide) (E317G) and estriol-16(beta-D-glucuronide) (E316G), inhibited MDR1-mediated E217G transport by 58% and 35%, respectively. In contrast, noncholestatic glucuronides, estradiol-3-(beta-D-glucuronide) (E23G) or estradiol-3-sulfate-17beta(beta-D-glucuronide) (E23SO417G), had no effect. E217G neither stimulated MDR1 ATPase activity nor inhibited verapamil-stimulated ATPase activity. Infusion of 1.5 micromol/L doxorubicin or 1 micromol/L taxol protected against cholestasis induced by E316G and E317G in isolated perfused rat liver. These studies identify E217G, and probably E316G and E317G, as endogenous substrates for MDR1.