Immunometabolic Blood Biomarkers of Developmental Trajectories of Depressive Symptoms: Findings From the ALSPAC Birth Cohort

Studies of longitudinal trends of depressive symptoms in young people could provide insight into aetiologic mechanism, heterogeneity and origin of common cardiometabolic comorbidities for depression. Depression is associated with immunological and metabolic alterations, but immunometabolic characteristics of developmental trajectories of depressive symptoms remain unclear. Using depressive symptoms scores measured on 10 occasions between ages 10 and 25 years in the Avon Longitudinal Study of Parents and Children (n=7302), we identified four distinct trajectories: low-stable (70% of the sample), adolescent-limited (13%), adulthood-onset (10%) and adolescent-persistent (7%). We examined associations of these trajectories with: i) anthropometric, cardiometabolic and psychiatric phenotypes using multivariable regression (n=1709-3410); ii) 67 blood immunological proteins and 57 metabolomic features using empirical Bayes moderated linear models (n=2059 and n=2240 respectively); and iii) 28 blood cell counts and biochemical measures using multivariable regression (n=2256). Relative to the low-stable group, risk of depression and anxiety in adulthood was higher for all other groups, especially in the adolescent-persistent (ORdepression=22.80, 95% CI 15.25-34.37; ORGAD=19.32, 95% CI 12.86-29.22) and adulthood-onset (ORdepression=7.68, 95% CI 5.31-11.17; ORGAD=5.39, 95% CI 3.65-7.94) groups. The three depression-related trajectories vary in their immunometabolic profile, with evidence of little or no alterations in the adolescent-limited group. The adulthood-onset group shows widespread classical immunometabolic changes (e.g., increased immune cell counts and insulin resistance), while the adolescent-persistent group is characterised by higher BMI both in childhood and adulthood with few other immunometabolic changes. These findings point to distinct mechanisms and intervention opportunities for adverse cardiometabolic profile in different groups of young people with depression.

The relationship between 'school readiness' and later persistent absenteeism

Post-pandemic school absence is an increasing concern for governments worldwide. Absence is associated with poor academic outcomes and long-term illness (physical and mental). Absenteeism increases the risk of financial difficulties in adulthood and involvement in the criminal justice system. We hypothesized that early childhood problems might be an antecedent of absenteeism. We tested this hypothesis by investigating the pre-pandemic association between school readiness and persistent absenteeism using a population-linked dataset. Analyses included 62,598 children aged 5-13 years from the Connected Bradford database (spanning academic years 2012/13 to 2019/20). Special educational needs status, English as an Additional Language status, socioeconomic status, sex and ethnicity were covariates significantly associated with persistent absenteeism. Children who were not 'school ready' had increased odds of being persistently absent later in their education journey after controlling for these covariates. School readiness was associated with even greater odds of being persistently absent over two or more years. These findings show (i) the seeds of absenteeism are sown early in childhood; (ii) absenteeism shows the hallmark of structural inequities; and (iii) the potential of 'school readiness' measures to identify children at risk of long-term disengagement from the education system.

Risk of not being in employment, education or training (NEET) in late adolescence is signalled by school readiness measures at 4-5 years

BACKGROUND

Not being in employment, education, or training (NEET) is associated with poor health (physical and mental) and social exclusion. We investigated whether England's statutory school readiness measure conducted at 4-5 years provides a risk signal for NEET in late adolescence.

METHODS

We identified 8,118 individuals with school readiness measures at 4-5 years and NEET records at 16-17 years using Connected Bradford, a bank of linked routinely collected datasets. Children were categorised as 'school ready' if they reached a 'Good Level of Development' on the Early Years Foundation Stage Profile. We used probit regression and structural equation modelling to investigate the relationship between school readiness and NEET status and whether it primarily relates to academic attainment.

RESULTS

School readiness was significantly associated with NEET status. A larger proportion of young people who were not school ready were later NEET (11%) compared to those who were school ready (4%). Most of this effect was attributable to shared relationships with academic attainment, but there was also a direct effect. Measures of deprivation and Special Educational Needs were also strong predictors of NEET status.

CONCLUSIONS

NEET risk factors occur early in life. School readiness measures could be used as early indicators of risk, with interventions targeted to prevent the long-term physical and mental health problems associated with NEET, especially in disadvantaged areas. Primary schools are therefore well placed to be public health partners in early intervention strategies.

Successful Crizotinib-targeted Therapy of Pediatric Unresectable ERC1::ALK Fusion Sarcoma

Anaplastic lymphoma kinase ( ALK )-fusion sarcomas are rare part of the emerging theoretically targetable tyrosine kinase RAS::MAPK pathway fusion myopericytic-ovoid sarcomas. We report our clinicopathologic and treatment experience with an ALK fusion sarcoma. A novel ELKS/RAB6-interacting/CAST family member 1 - unaligned ALK fusion infiltrative nonmetastatic low-grade sarcoma of the right hand of a 15-month-old male was treated with crizotinib, an ALK tyrosine kinase inhibitor as oral monotherapy, inducing complete radiographic and clinical resolution by 10 months and sustained response now over 12 months after elective discontinuation. Crizotinib can successfully be used to treat unresectable novel ALK fusion sarcomas.

Potential for England's statutory school entry assessment to identify special educational needs and reveal structural inequalities: a population-based study

OBJECTIVE

To investigate at a population level whether England's universal assessment of 'school readiness' is associated with later identification of special educational needs (SEN). Also, whether ethnic differences exist in SEN identification (white British versus ethnic minority) and whether this varies as a function of school readiness.

METHOD

Analysis included 53 229 individuals aged 5-12 years from the Connected Bradford Database (2012/2013-2019/2020). Logistic regression analyses examined: (1) whether reaching a 'good level of development' on England's 'school readiness' assessment was associated with later SEN identification; and (2) whether interactions exist between school readiness and ethnicity.

RESULTS

32 515 of 53 229 children reached a good level of development, of which 3036 (9.3%) were identified as having SEN. In contrast, 10 171 of 20 714 (49.1%) of children who did not reach a good level of development were later identified as having SEN. Children not reaching a good level of development had increased odds of being later identified as having SEN after controlling for covariates (OR: 8.50, 95% CI: 8.10 to 8.91). In children who did not reach a good level of development, white British children had higher odds of being identified as having SEN compared with ethnic minority peers (OR: 1.22, 95% CI: 1.11 to 1.34). No ethnic differences of having SEN were observed in children reaching a good level of development (OR: 1.04, 95% CI: 0.93 to 1.16).

CONCLUSIONS

School readiness assessments are associated with later SEN identification. Structural inequalities may exist in SEN identification in children not entering formal education 'school ready'. Such assessments could facilitate earlier identification of SEN and reduce structural inequalities in its identification.

Large-scale assessment of 7-11-year-olds' cognitive and sensorimotor function within the Born in Bradford longitudinal birth cohort study

Background: Cognitive ability and sensorimotor function are crucial aspects of children's development, and are associated with physical and mental health outcomes and educational attainment. This paper describes cross-sectional sensorimotor and cognitive function data collected on over 15,000 children aged 7-10 years, collected as part of the Born in Bradford (BiB) longitudinal birth-cohort study. Methodological details of the large-scale data collection process are described, along with initial analyses of the data involving the relationship between cognition/sensorimotor ability and age and task difficulty, and associations between tasks. Method: Data collection was completed in 86 schools between May 2016 and July 2019. Children were tested at school, individually, using a tablet computer with a digital stylus or finger touch for input. Assessments comprised a battery of three sensorimotor tasks (Tracking, Aiming, & Steering) and five cognitive tasks (three Working Memory tasks, Inhibition, and Processing Speed), which took approximately 40 minutes. Results: Performance improved with increasing age and decreasing task difficulty, for each task. Performance on all three sensorimotor tasks was correlated, as was performance on the three working memory tasks. In addition, performance on a composite working memory score correlated with performance on both inhibition and processing speed. Interestingly, within age-group variation was much larger than between age-group variation. Conclusions: The current project collected computerised measures of a range of cognitive and sensorimotor functions at 7-10 years of age in over 15,000 children. Performance varied as expected by age and task difficulty, and showed the predicted correlations between related tasks. Large within-age group variation highlights the need to consider the profile of individual children in studying cognitive and sensorimotor development. These data can be linked to the wider BiB dataset including measures of physical and mental health, biomarkers and genome-wide data, socio-demographic information, and routine data from local health and education services.

Exclusion of Reproductive-aged Women in COVID-19 Vaccination and Clinical Trials

INTRODUCTION

We analyzed the exclusion of pregnant and breastfeeding individuals and those capable of pregnancy in COVID-19 vaccine and clinical treatment trials.

METHODS

Inclusion and exclusion criteria were extracted from all listed COVID-19 vaccine and treatment clinical trials from May 1, 2020, to October 31, 2020, using the U.S. National Library of Medicine database. We report rates of rates of exclusion for pregnant and lactating individuals and requirements for contraception for pregnancy-capable participants in COVID-19 vaccine and treatment clinical trials. The analysis included the association between clinical trial exclusion and vaccine and treatment type, study location, sponsor, and phase.

RESULTS

Pregnant and lactating individuals were explicitly excluded from most COVID-19 vaccine and treatment clinical trials. Of the 90 vaccine trials, 88 (97.8%) excluded pregnant individuals, 73 (81.1%) excluded lactating individuals, and 56 (62.2%) required contraception use. Of the 495 treatment trials, 350 (70.7%) excluded pregnant individuals, 269 (54.3%) excluded lactating individuals, and 91 (18.4%) required contraception use. Although vaccine type was not associated with pregnancy exclusion, it was associated with lactation exclusion (p = .01) and contraception requirement (p < .001). Treatment type was associated with pregnancy exclusion, lactation exclusion, and contraception requirement (all p < .001).

CONCLUSIONS

COVID-19 vaccination and treatment clinical trials mirrored historical trends restricting participation owing to pregnancy, lactation, and contraception nonuse, despite known safety profiles. People of childbearing potential should be considered for and afforded the same opportunity as males to make informed decisions on study participation, particularly in the setting of a global pandemic.

Large-scale assessment of 7-11-year-olds’ cognitive and sensorimotor function within the Born in Bradford longitudinal birth cohort study

Background: Cognitive ability and sensorimotor function are crucial aspects of children’s development, and are associated with physical and mental health outcomes and educational attainment. The current project forms part of the Born in Bradford (BiB) longitudinal birth-cohort study, and involved measuring sensorimotor and cognitive function in over 15,000 children aged 7-10 years. This paper describes the large-scale data collection process and presents initial analyses of the data, including the relationship between cognition/sensorimotor ability and age and task difficulty, and associations between tasks. Method: Data collection was completed in 86 schools between May 2016 and July 2019. Children were tested at school, individually, using a tablet computer with a digital stylus or finger touch for input. Assessments comprised a battery of three sensorimotor tasks (Tracking, Aiming, & Steering) and five cognitive tasks (three Working Memory tasks, Inhibition, and Processing Speed), which took approximately 40 minutes. Results: Performance improved with increasing age and decreasing task difficulty, for each task. Performance on all three sensorimotor tasks was correlated, as was performance on the three working memory tasks. In addition, performance on a composite working memory score correlated with performance on both inhibition and processing speed. Interestingly, within age-group variation was much larger than between age-group variation. Conclusions: The current project collected computerised measures of a range of cognitive and sensorimotor functions at 7-10 years of age in over 15,000 children. Performance varied as expected by age and task difficulty, and showed the predicted correlations between related tasks. Large within-age group variation highlights the need to consider the profile of individual children in studying cognitive and sensorimotor development. These data can be linked to the wider BiB dataset including measures of physical and mental health, biomarkers and genome-wide data, socio-demographic information, and routine data from local health and education services.

A systematic review of randomized and case-controlled trials investigating the effectiveness of school-based motor skill interventions in 3- to 12-year-old children

BACKGROUND

Research suggests that children identified with impaired motor skills can respond well to intensive therapeutic interventions delivered via occupational and physical therapy services. There is, however, a need to explore alternative approaches to delivering interventions outside traditional referral-based clinic settings because limited resources mean such health services often struggle to meet demand. This review sets out to systematically assess the evidence for and against school-based interventions targeted at improving the motor skills of children aged between 3 and 12 years old.

METHOD

Five electronic databases were searched systematically (AMED, CINAHL, Cochrane, Medline, and PsycINFO) for peer-reviewed articles published between January 2012 and July 2018. Studies were eligible if they implemented a school-based motor skill intervention with a randomized or case-controlled trial design that objectively measured motor skills as an outcome, which were not specific to an athletic or sporting skill. Participants had to be aged between 3 and 12 years old and free from neurological disorders known to affect muscle function. Risk of bias was assessed using the Cochrane risk of bias tool.

RESULTS

Twenty-three studies met the inclusion criteria. These studies encompassed interventions targeted at training: fundamental movement skills, handwriting, fine, and global motor skills. The majority of these studies reported beneficial impact on motor function specifically, but some interventions also assessed subsequent impacts on activity and participation (but not well-being). A number of the studies had methodological shortcomings that means these results need to be interpreted with caution.

CONCLUSIONS

Schools appear to be an effective setting for motor skill interventions, but the extent of benefit likely depends on the type of intervention. Moreover, confirmation is needed as to whether benefits extend beyond motor function into everyday activities, participation, and well-being. Future research should include follow-up measures to assess the longer term efficacy of school-based interventions.

Laparoscopic Motor Learning and Workspace Exploration

BACKGROUND

Laparoscopic surgery requires operators to learn novel complex movement patterns. However, our understanding of how best to train surgeons' motor skills is inadequate, and research is needed to determine optimal laparoscopic training regimes. This difficulty is confounded by variables inherent in surgical practice, for example, the increasing prevalence of morbidly obese patients presents additional challenges related to restriction of movement because of abdominal wall resistance and reduced intra-abdominal space. The aim of this study was to assess learning of a surgery-related task in constrained and unconstrained conditions using a novel system linking a commercially available robotic arm with specialised software creating the novel kinematic assessment tool (Omni-KAT).

METHODS

We created an experimental tool that records motor performance by linking a commercially available robotic arm with specialized software that presents visual stimuli and objectively measures movement outcome (kinematics). Participants were given the task of generating aiming movements along a horizontal plane to move a visual cursor on a vertical screen. One group received training that constrained movements to the correct plane, whereas the other group was unconstrained and could explore the entire "action space."

RESULTS

The tool successfully generated the requisite force fields and precisely recorded the aiming movements. Consistent with predictions from structural learning theory, the unconstrained group produced better performance after training as indexed by movement duration (p < 0.05).

CONCLUSION

The data showed improved performance for participants who explored the entire action space, highlighting the importance of learning the full dynamics of laparoscopic instruments. These findings, alongside the development of the Omni-KAT, open up exciting prospects for better understanding of the learning processes behind surgical training and investigate ways in which learning can be optimized.

Optic neuropathy endemic in secondary school children in Dar es Salaam, Tanzania

AIM

To investigate the prevalence and causes of optic neuropathy, reported as epidemic in 1997, among secondary school students in Dar es Salaam, Tanzania.

PATIENTS AND METHODS

First year students (n = 10,892) from 63 secondary schools located within 30 km from the base hospital were interviewed and had a visual acuity (VA) screening test. Students failing the 6/12-line in either eye were defined as having "poor eyesight" and referred to the base hospital where an optometrist re-tested VA and refracted them. An ophthalmologist examined students with VA of 6/12 or worse in either eye and visual impairment was defined as VA of worse than 6/12 with best correction. Associations between optic neuropathy, socioeconomic status and educational results were investigated.

RESULTS

Students' ages ranged from 12 to 22 (mean 15.2) years; 50.6% were male. The prevalence of optic neuropathy was 0.3 (SD 0.051)%. The condition affected older students and was associated with the family having fewer economic possessions (car, computer, television). Optic neuropathy accounted for 19/33 (58%) of bilateral visual impairment cases. No effect of the disease on educational performance was identified.

CONCLUSION

Optic neuropathy remains a significant problem in this population and can now be termed endemic rather than epidemic. Further research into its causes is required.

Therapeutic effects of cysteine protease inhibition in allergic lung inflammation: inhibition of allergen-specific T lymphocyte migration

OBJECTIVE AND DESIGN

We have evaluated the effects of the broad-spectrum cysteine protease inhibitor E64 on allergic lung inflammation in the mouse ovalbumin model of human asthma. We have also characterised membrane-associated cathepsin enzyme activity on a range of cell types.

MATERIALS

Balb/C mice, E64 and CA074, various cell lines.

TREATMENT

E64 was administered by subcutaneous minipump into ovalbumin-sensitised mice prior to intranasal ovalbumin challenge. The effect of E64 on ovalbumin-induced inflammation in vivo and ovalbumin-specific T cell proliferation in vitro and ex vivo was examined. Membrane-associated cathepsin activity on various cell types was measured.

RESULTS

E64 treatment (0.36-0.48 mg/day) led to a significant reduction in eosinophil numbers and lung weights in the mouse model. Histological examination of lungs confirmed the anti-inflammatory effect. E64 greatly reduced ovalbumin-specific T cell numbers in the lymph nodes draining the lung following intranasal challenge whilst an accumulation of these T cells was found in the 'priming' lymph nodes. An analysis of various cells involved in lymphocyte priming and migration revealed that monocytes, dendritic cells and endothelial cells express high levels of membrane-associated cathepsin B activity.

CONCLUSIONS

Since E64 is not cell permeable and does not inhibit antigen-induced T cell proliferation in vitro or in vivo, the data indicate that membrane-associated cysteine proteases, possibly cathepsin B, may regulate T lymphocyte migration in vivo.

1,6-interactions between dimethylamino and aldehyde groups in two biphenyl derivatives

The title compounds, 2-(dimethylamino)biphenyl-2'-carboxaldehyde, C15H15NO, and 2-(dimethylamino)biphenyl-2',6'-dicarboxaldehyde, C16H15NO2, show similar 1,6-interactions [N...C=O 2.929 (3) to 3.029 (3) A] between the dimethylamino and aldehyde groups located in the ortho positions of the two rings, which lie at 58.1 (1)-62.4 (1) degrees to each other.

Statistical analysis of spatial pattern: a comparison of grid and hierarchical sampling approaches

Previous studies have combined random-site hierarchical sampling designs with analysis of variance techniques, and grid sampling with spatial autocorrelation analysis. We illustrate that analysis techniques and sampling designs are interchangeable using densities of an infaunal bivalve from a study in Poverty Bay, New Zealand. Hierarchical designs allow the estimation of variances associated with each level, but high-level factors are imprecisely estimated, and they are inefficient for describing spatial pattern. Grid designs are efficient for describing spatial pattern, and are amenable to conventional analysis. Our example deals with a continuous spatial habitat, but our conclusions also apply in disjunct or patchy habitats. The influence of errors in positioning is also assessed. The advantages of systematic sampling are reviewed, and more efficient hierarchical approaches are identified. The distinction between biological and statistical significance in all analyses is emphasised.

Fast measurements of the motion and velocity spectrum of blood using MR tagging

A new method is presented for tracking the motion of blood and determining its velocity spectrum from magnetic resonance data collected within a single heartbeat. The method begins by tagging a column of blood in a vessel by combining a 1D SPAMM excitation with a 2D cylindrical excitation. A series of 1D projections of the tagging pattern is acquired from a train of gradient echoes. The influence of specific excitation profiles and velocity profiles on the motion of the tags is explored for steady flow. It is shown mathematically, and confirmed with phantom experiments, that the velocity of a tag equals the mean velocity of the excited fluid when the velocity spectrum is symmetric about its mean velocity. The velocity spectrum is derived by analyzing the interference between tags moving at different velocities. This appears to be the first use of magnitude tagging to obtain velocity spectra. Representative measurements in a human aorta are presented to assess feasibility in vivo. Magn Reson Med 45:461-469, 2001.

Partial discrete Fourier transform (PDFT) multiband encoding

For conventional multiband encoding techniques such as Hadamard encoding, scan time scales linearly with the number of slices encoded simultaneously. In this work, a new multiband encoding technique called partial discrete Fourier transform (PDFT) encoding is introduced, which overcomes this restriction. This technique incorporates the principle of partial Fourier imaging, allowing the tradeoff of SNR and imaging time without changing the number of slices. The theory behind PDFT encoding and its inherent sensitivity to phase errors are outlined. The theory was validated through simulations, showing that phase errors result in degraded slice localization. The feasibility of PDFT encoding of 12 slices was tested with experimental excitation profile measurements and heart images of a human subject using commercial MRI equipment. Imaging time was reduced to 66% with SNR reduced to 82%. Magn Reson Med 45:118-127, 2001.

Comparison of the nucleic acid-based crosslinking hybridization assay and the branched DNA signal amplification assay in the quantitative measurement of serum hepatitis B virus DNA

Quantitative measurement of hepatitis B virus (HBV) DNA has become important in the clinical diagnosis of patients with chronic hepatitis B, especially in patients with hepatitis B e antigen (HBeAg)-negative precore mutant and in patients who received treatment with interferon or antiviral agents. Two different hybridization assays for quantitative measurement of HBV DNA: Naxcor crosslinking assays and Chiron branched DNA signal amplification (bDNA) assay, were applied to 158 serum samples which were positive for HBV DNA by polymerase chain reaction. Among 158 serum samples, 135 samples (85.4%) were positive by the crosslinking assay and 129 samples (81.6%) were positive by the bDNA assay in the quantification of serum HBV DNA (P > 0.05). Serum HBV DNA levels obtained from both assays showed a good linear correlation (r = 0.91, P < 0.001). The sensitivity of both assays in HBeAg-positive samples was 90.5%, significantly higher than in HBeAg-negative samples (69.6% for the crosslinking assay and 56.5% for the bDNA assay, P < 0.05). In HBeAg-negative patients with elevated serum alanine transaminase levels, the so-called precore HBV mutant, the detection sensitivity for HBV DNA was better in the crosslinking assay (83%) than in the bDNA assay (61%). The crosslinking assay was less time consuming than the bDNA assay in performing the measurement of serum HBV DNA (6 hours vs. 20 hours). In conclusion, Naxcor crosslinking hybridization assay was equally as sensitive as Chiron bDNA assay in the quantitative measurement of serum HBV DNA. Less time-consuming procedures and better sensitivity in the detection of HBeAg-negative samples with elevated serum alanine transaminase levels may favor the clinical use of the crosslinking assay.

Photo-cross-linkable oligonucleotide probes for in situ hybridization assays

In situ hybridization techniques have been an important research tool since first introduced 30 years ago, and more recently clinical applications have been expanding greatly. Still, further improvements in the assay sensitivity and protocols that are amenable to routine clinical use are desired. We use a novel photo-cross-linking technology to irreversibly bind short oligonucleotide probes to the target sequence following a hybridization period. The cross-linking agent is incorporated into the backbone of the probe and is activated to react with pyrimidines in the opposite strand by near-UV (300-370 nm) irradiation. By locking the probe to the target, very stringent wash conditions can be used that would otherwise completely remove probes that are hybridized but not cross-linked to the target. Consequently, the probe-specific signal is maximized, while the background signal is minimized to the greatest extent possible with the stringency of the wash. The use of short, photo-cross-linkable probes presents a new strategy for maximizing the sensitivity of probe hybridization or signal amplification-based in situ techniques.

Open reduction and cementation for femoral head fracture secondary to avascular necrosis: preliminary report

Current treatment for femoral head avascular necrosis has shown good results in early stages of disease, but are not as impressive after progression to collapse. We treated 19 patients (20 hips) with Stage III avascular necrosis (AVN) by open reduction augmented by methylmethacrylate cementation. Follow up ranges from 6 months to 2 years (average = 8.7 months). We followed patient progress with pre- and post-operative Harris Hip Scores, Womac Osteoarthritis Index and a Health Status Questionnaire (SF36). All patients realized immediate post-operative pain relief and improvement in function. Harris Hip, Womac Osteoarthritis Index and SF36 physical health scores improved significantly from 54.0 to 79.5 (p < 0.05), 54.3 to 29.8 (p < 0.05) and 28.4 to 42.4 (p < 0.05), respectively. Three patients had a conversion to total hip arthroplasty. Cementation is technically simple, burns no bridges and enables patients a rapid recovery. The long term results, in regards to progression of disease and secondary arthritis, are unknown.

Comparison of the nucleic acid-based crosslinking hybridization assay and the branched DNA signal amplification assay in the quantitative measurement of serum hepatitis B virus DNA

Quantitative measurement of hepatitis B virus (HBV) DNA has become important in the clinical diagnosis of patients with chronic hepatitis B, especially in patients with hepatitis B e antigen (HBeAg)-negative precore mutant and in patients who received treatment with interferon or antiviral agents. Two different hybridization assays for quantitative measurement of HBV DNA: Naxcor crosslinking assays and Chiron branched DNA signal amplification (bDNA) assay, were applied to 158 serum samples which were positive for HBV DNA by polymerase chain reaction. Among 158 serum samples, 135 samples (85.4%) were positive by the crosslinking assay and 129 samples (81.6%) were positive by the bDNA assay in the quantification of serum HBV DNA (P > 0.05). Serum HBV DNA levels obtained from both assays showed a good linear correlation (r = 0.91, P < 0.001). The sensitivity of both assays in HBeAg-positive samples was 90.5%, significantly higher than in HBeAg-negative samples (69.6% for the crosslinking assay and 56.5% for the bDNA assay, P < 0.05). In HBeAg-negative patients with elevated serum alanine transaminase levels, the so-called precore HBV mutant, the detection sensitivity for HBV DNA was better in the crosslinking assay (83%) than in the bDNA assay (61%). The crosslinking assay was less time consuming than the bDNA assay in performing the measurement of serum HBV DNA (6 hours vs. 20 hours). In conclusion, Naxcor crosslinking hybridization assay was equally as sensitive as Chiron bDNA assay in the quantitative measurement of serum HBV DNA. Less time-consuming procedures and better sensitivity in the detection of HBeAg-negative samples with elevated serum alanine transaminase levels may favor the clinical use of the crosslinking assay.