Interaction between clinicians and artificial intelligence to detect fetal atrioventricular septal defects on ultrasound: how can we optimize collaborative performance?

OBJECTIVES

Artificial intelligence (AI) has shown promise in improving the performance of fetal ultrasound screening in detecting congenital heart disease (CHD). The effect of giving AI advice to human operators has not been studied in this context. Giving additional information about AI model workings, such as confidence scores for AI predictions, may be a way of improving performance further. Our aims were to investigate whether AI advice improved overall diagnostic accuracy (using a single CHD lesion as an exemplar), and to see what, if any, additional information given to clinicians optimized the overall performance of the clinician-AI team.

METHODS

An AI model was trained to classify a single fetal CHD lesion (atrioventricular septal defect, AVSD), using a retrospective cohort of 121,130 cardiac four chamber images extracted from 173 ultrasound scan videos (98 with normal hearts, 75 with AVSD). A ResNet50 model architecture was used. Temperature scaling of model prediction probability was performed on a validation set, and gradient-weighted class activation maps (grad-CAMs) produced. Ten clinicians (two consultant fetal cardiologists, three trainees in pediatric cardiology, and five fetal cardiac sonographers) were recruited from a center of fetal cardiology to participate. Each participant was shown 2000 fetal four chamber images in a random order (1,000 normal and 1,000 AVSD). The dataset was comprised of 500 images, each shown in four conditions: 1) image alone without AI output; 2) image with binary AI classification; 3) image with AI model confidence; 4) image with gradient-weighted class activation map image overlays. The clinicians were asked to classify each image as normal or AVSD.

RESULTS

20,000 image classifications were recorded from 10 clinicians. The AI model alone achieved an accuracy of 0.798 (95% CI 0.760 - 0.832), sensitivity of 0.868 (95% CI 0.834 - 0.902) and specificity of 0.728 (95% CI 0.702 - 0.754, and the clinicians without AI achieved an accuracy of 0.844 (95% CI 0.834 - 0.854), sensitivity of 0.827 (95% CI 0.795 - 0.858) and specificity of 0.861 (95% CI 0.828 - 0.895). Showing a binary (normal or AVSD) AI model output resulted in significant improvement in accuracy to 0.865 (p <0.001). This effect was seen in both experienced and less experienced participants. Giving incorrect AI advice resulted in significant deterioration in overall accuracy from 0.761 to 0.693 (p <0.001), which was driven by an increase in both type I and type II error by the clinicians. This effect was worsened by showing model confidence (accuracy 0.649, p <0.001) or grad-CAM (accuracy 0.644, p <0.001).

CONCLUSIONS

AI has the potential to improve performance when used in collaboration with clinicians, even if the model performance does not reach expert level. Giving additional information about model workings such as model confidence and class activation map image overlays did not improve overall performance, and actually worsened performance for images where the AI model was incorrect. This article is protected by copyright. All rights reserved.

Prognostic value of pulmonary transit time by cardiac magnetic resonance in patients with heart failure with preserved ejection fraction

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre

Background

Quantifying pulmonary transit time (PTT) from cardiac magnetic resonance (CMR) first pass perfusion imaging is a novel technique for the evaluation of haemodynamic congestion in heart failure. Previous studies have demonstrated that PTT is prolonged in patients with heart failure with reduced ejection fraction (HFrEF) and that it provides independent prognostic information in this patient group. However, the potential diagnostic and prognostic roles of PTT assessment in patients with heart failure with preserved ejection fraction (HFpEF) remain to be established.

Aim

To compare PTT in healthy controls and in patients with HFpEF, and to determine the prognostic value of PTT in HFpEF.

Methods

In a prospective, observational study, HFpEF and age-matched control subjects underwent multi-parametric CMR at 3-Tesla, comprising quantitative left ventricular volumetric assessment using a standard steady-state free precession (SSFP) pulse sequence, and first-pass perfusion imaging at rest using a T1-weighted segmented inversion recovery gradient echo sequence (following injection of 0.04mmol/kg of contrast). PTT was calculated as the time interval between the peaks of signal intensity curves in the right and left ventricular blood pools (defined on the basal slice of the rest perfusion images). The primary endpoint was the composite of death or hospitalisation with heart failure.

Results

88 HFpEF patients (age 73 ± 9 years, 51% male, EF 56.4 ± 5.6%) and 40 controls (age 73 ± 5 years, 43% male, EF 58.5 ± 4.7%) were studied. PTT was comparable in HFpEF patients (7.7 ± 3.8s) and in healthy controls (7.5 ± 1.8, p = 0.69). Normalised to cardiac cycle lengths, PTT remained comparable in HFpEF patients and healthy controls (8.5 ± 4.0 cardiac cycles versus 7.8 ± 1.6 cardiac cycles, respectively, p = 0.19). In the HFpEF group, during median follow-up of 3.4 years, there were 38 events (25 hospitalisations with heart failure, 13 deaths); a significant relationship between survival and PTT was not demonstrated (HR 1.06 [0.99,1.14] for a one-unit increase, p = 0.098).

Conclusion

In HFpEF, PTT is not prolonged compared with PTT in healthy subjects. Unlike in HFrEF, PTT does not appear to be diagnostically or prognostically significant in HFpEF.

Figure 1: Graph showing signal intensity curves in the right (red) and left (green) ventricular blood pools

Figure 2: Kaplan-Meier plot showing comparable rates of the composite endpoint in patients with PTT greater/less than median PTT (8 cardiac cycles)

Primary HPV and Molecular Cervical Cancer Screening in US Women Living With Human Immunodeficiency Virus

BACKGROUND

Primary human papillomavirus (HPV) screening (PHS) utilizes oncogenic human papillomavirus (oncHPV) testing as the initial cervical cancer screening method and typically, if positive, additional reflex-triage (eg, HPV16/18-genotyping, Pap testing). While US guidelines support PHS usage in the general population, PHS has been little studied in women living with HIV (WLWH).

METHODS

We enrolled n = 865 WLWH (323 from the Women's Interagency HIV Study [WIHS] and 542 from WIHS-affiliated colposcopy clinics). All participants underwent Pap and oncHPV testing, including HPV16/18-genotyping. WIHS WLWH who tested oncHPV[+] or had cytologic atypical squamous cells of undetermined significance or worse (ASC-US+) underwent colposcopy, as did a random 21% of WLWH who were oncHPV[-]/Pap[-] (controls). Most participants additionally underwent p16/Ki-67 immunocytochemistry.

RESULTS

Mean age was 46 years, median CD4 was 592 cells/µL, 95% used antiretroviral therapy. Seventy WLWH had histologically-determined cervical intraepithelial neoplasia grade 2 or greater (CIN-2+), of which 33 were defined as precancer (ie, [i] CIN-3+ or [ii] CIN-2 if concurrent with cytologic high grade squamous intraepithelial lesions [HSILs]). PHS had 87% sensitivity (Se) for precancer, 9% positive predictive value (PPV), and a 35% colposcopy referral rate (Colpo). "PHS with reflex HPV16/18-genotyping and Pap testing" had 84% Se, 16% PPV, 30% Colpo. PHS with only HPV16/18-genotyping had 24% Colpo. "Concurrent oncHPV and Pap Testing" (Co-Testing) had 91% Se, 12% PPV, 40% Colpo. p16/Ki-67 immunochemistry had the highest PPV, 20%, but 13% specimen inadequacy.

CONCLUSIONS

PHS with reflex HPV16/18-genotyping had fewer unnecessary colposcopies and (if confirmed) could be a potential alternative to Co-Testing in WLWH.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

The effect of DAFNE education, continuous subcutaneous insulin infusion, or both in a population with type 1 diabetes in Scotland

AIM

To investigate the effect of DAFNE and continuous subcutaneous insulin infusion in clinical practice.

METHODS

Within NHS Lothian, continuous subcutaneous insulin infusion started in 2004 and DAFNE education began in 2006. We extracted anonymized data from the national database for all those aged > 18 years with type 1 diabetes having a Dose Adjustment For Normal Eating course or continuous subcutaneous insulin infusion start date (n = 4617).

RESULTS

In total, 956 persons received DAFNE education, and 505 had received an insulin pump, 208 of whom had DAFNE education followed by insulin pump. Mean (SD) HbA_1c before DAFNE education was 68 (15) mmol/mol (8.4% [1.4%]) and 66 (13) mmol/mol (8.2% [1.2%]) before continuous subcutaneous insulin infusion. In the year following DAFNE education, the mean fall in within-person HbA_1c was 3.8 mmol/mol (95% CI 4.0 to 3.4; 0.3% [0.4% to 0.3%]). Those with the poorest control (HbA_1c ≥ 85 mmol/mol [9.9%]) experienced the largest decline (15.7 mmol/mol [1.4%]). Those in the lowest HbA_1c band at initiation (< 53 mmol/mmol [7.0%]) experienced a rise. In the year following continuous subcutaneous insulin infusion initiation there was a mean fall in within-person HbA_1c of 6.6 mmol/mol (6.8 to 6.4; 0.6% [0.6% to 0.6%]). In those with the poorest control (HbA_1c ≥ 85 mmol/mol [9.9%]), the mean fall in HbA_1c was 22.2 mmol/mol (23 to 21; 2.0% [2.1% to 1.9%]). Continuous subcutaneous insulin infusion effectiveness was not different with or without DAFNE education. The effects of both interventions were sustained over 5 years.

CONCLUSIONS

Both DAFNE education and insulin pump therapy had the greatest effect on HbA_1c in those with higher baseline values. There was little difference to attained HbA_1c when Dose Adjustment For Normal Eating education was introduced before insulin pump therapy.

Nasal fractures: a dedicated clinic providing reduction under local anaesthesia improves time to manipulation

INTRODUCTION

Guidelines for nasal injury state that assessment should be at 7-10 days post-injury and manipulation within 14 days. We performed a plan, do, study, act improvement cycle to assess whether a dedicated nasal fracture service led to better outcomes.

MATERIALS AND METHODS

A retrospective study was carried out of all patients undergoing manipulation under anaesthesia for nasal trauma between February 2013 and December 2016 in a district general hospital. A dedicated nasal fracture clinic providing manipulation under local anaesthesia was implemented followed by a prospective study of all patients presenting to the clinic between February and November 2017. Main outcome measures included time from injury to otolaryngology assessment, time from injury to manipulation and incidence of secondary septorhinoplasty.

RESULTS

The retrospective series involved 525 patients including 381 males (72.6%) and 144 females (27.4%). Mean time from injury to assessment was 10 days. Mean time from injury to surgery was 14.5 days. Mean time from assessment to surgery was five days. The incidence of septorhinoplasty was 2.3%. The prospective series involved 119 patients including 78 males (65.5%) and 41 females (34.5%). Following implementation of a nasal fracture clinic, mean time from injury to assessment and manipulation was 6.1 days and 5.4% of patients underwent septorhinoplasty for secondary deformity.

DISCUSSION

Implementation of a nasal fracture clinic providing reduction under local anaesthesia reduced the time to assessment and manipulation. The incidence of septorhinoplasty is low following reduction under general or local anaesthesia. Assessment earlier than seven days is feasible and advice for referral can be changed accordingly.

Health Professional Training and Capacity Strengthening Through International Academic Partnerships: The First Five Years of the Human Resources for Health Program in Rwanda

BACKGROUND

The Rwanda Human Resources for Health Program (HRH Program) is a 7-year (2012-2019) health professional training initiative led by the Government of Rwanda with the goals of training a large, diverse, and competent health workforce and strengthening the capacity of academic institutions in Rwanda.

METHODS

The data for this organizational case study was collected through official reports from the Rwanda Ministry of Health (MoH) and 22 participating US academic institutions, databases from the MoH and the College of Medicine and Health Sciences (CMHS) in Rwanda, and surveys completed by the co-authors.

RESULTS

In the first 5 years of the HRH Program, a consortium of US academic institutions has deployed an average of 99 visiting faculty per year to support 22 training programs, which are on track to graduate almost 4600 students by 2019. The HRH Program has also built capacity within the CMHS by promoting the recruitment of Rwandan faculty and the establishment of additional partnerships and collaborations with the US academic institutions.

CONCLUSION

The milestones achieved by the HRH Program have been substantial although some challenges persist. These challenges include adequately supporting the visiting faculty; pairing them with Rwandan faculty (twinning); ensuring strong communication and coordination among stakeholders; addressing mismatches in priorities between donors and implementers; the execution of a sustainability strategy; and the decision by one of the donors not to renew funding beyond March 2017. Over the next 2 academic years, it is critical for the sustainability of the 22 training programs supported by the HRH Program that the health-related Schools at the CMHS significantly scale up recruitment of new Rwandan faculty. The HRH Program can serve as a model for other training initiatives implemented in countries affected by a severe shortage of health professionals.

Prolonged Amenorrhea and Resumption of Menses in Women with HIV

OBJECTIVE

To compare etiologies of prolonged amenorrhea in a cohort of HIV-infected women with a cohort of similar uninfected at-risk women.

MATERIALS AND METHODS

Women from the Women's Interagency HIV Study were seen every 6 months, and completed surveys including questions about their menstruation. Those who reported no vaginal bleeding for at least 1 year ("prolonged amenorrhea") with subsequent resumption of bleeding were compared with women in whom bleeding had stopped permanently ("menopause"). Characteristics associated with reversible prolonged amenorrhea were ascertained.

RESULTS

Of 828 women with prolonged amenorrhea, 37.6% had reversible amenorrhea and 62.4% never resumed menses. HIV-seropositive women with prolonged amenorrhea were significantly younger at cessation of menses than HIV-negative women (p < 0.0001). Of those with reversible prolonged amenorrhea, approximately half were taking medications associated with amenorrhea, including 95 (30.6%) hormonal contraception, 80 (25.7%) opiates/stimulants, 16 (5.1%) psychotropic medications, and 6 (1.9%) chemotherapy. HIV-seropositive women were less likely to have medications as a cause of amenorrhea than seronegative women (p = 0.02). In multivariable analysis, women with reversible prolonged amenorrhea of unknown etiology were younger (p < 0.0001), more often obese (p = 0.03), and less educated (p = 0.01) than those with permanent amenorrhea. Among HIV-seropositive women, markers of severe immunosuppression were not associated with prolonged amenorrhea.

CONCLUSION

Women with HIV infection have unexplained prolonged amenorrhea more often than at-risk seronegative women. This is especially common among obese, less-educated women. Prolonged amenorrhea in the HIV-seropositive women should be evaluated and not be presumed to be to the result of menopause.

Low Birth Weight in Human Immunodeficiency Virus-Exposed Uninfected Infants in Bronx, New York

BACKGROUND

Prevention of mother-to-child transmission of human immunodeficiency virus (HIV) with antiretroviral therapy (ART) has been highly successful. However, HIV-exposed uninfected (HIV-EU) infants might be at increased risk for low birth weight and/or preterm birth. We compared the birth weights and gestational ages of HIV-EU infants to those of HIV-unexposed control infants in Bronx, New York, an epicenter of the HIV epidemic in the United States.

METHODS

This study was performed with a retrospective cohort of HIV-EU infants born at Montefiore Medical Center between 2008 and 2012 and HIV-unexposed control infants. Each HIV-EU infant was matched according to year of birth with 5 HIV-unexposed controls from the New York City Department of Health and Mental Hygiene birth certificate database. We used regression models to assess the association between HIV exposure and birth weight while controlling for potential confounders. A secondary analysis was performed to determine the association of maternal protease inhibitor-based ART use and birth weight among HIV-EU infants.

RESULTS

We included 155 HIV-EU infants born between 2008 and 2012 (51% female, 61% black, 32% Hispanic) and 775 HIV-unexposed infants. The mean (± standard deviation) unadjusted birth weights were 2971 ± 616 g (HIV-EU infants) and 3163 ± 644 g (HIV-unexposed infants) (P < .01). Multivariable regression revealed significantly lower birth weight for the HIV-EU infants (difference, -101.5 g [95% confidence interval, -181.4 to -21.6]). We found no difference in mean birth weight or gestational age with maternal protease inhibitor-based ART use when compared to the use of other regimens.

CONCLUSIONS

We found significantly lower birth weight among HIV-EU infants. Long-term prospective studies are necessary to determine the implications of this finding on infant growth and development.

Endotoxin and Bacterial Contamination of Dialysis Center Water and Dialysate; a Cross Sectional Survey

The bacterial and endotoxin levels of purified water and effluent dialysate were examined in a cross section of dialysis centers in the central United States. All samples were collected within a four-hour drive of the University of Louisville and were collected, processed and analyzed by our personnel, to eliminate variability in sample handling. A medium capable of higher bacteria recovery from aqueous environments than those ordinarily employed in clinical assays was used. Endotoxins were determined by a quantitative colorimetric assay.

By the more sensitive bacterial assay 53% of the centers had bacterial counts above the AAMI standard of 200 colony-forming units per ml (CFU/ml) for water and 35% of the centers had bacterial counts above the 2000 CFU/ml standard for dialysate in at least one sampling period. The samples showed 35% and 19% of water and dialysate above the standards, respectively. While there are no standards for endotoxin concentrations in water used to prepare dialysate, 2% of the centers had endotoxin levels in their water above five endotoxin units per ml (5 EU/ml = 1 ng/ml in our assay kit), the limit set by the AAMI standards for reprocessor water. Both bacterial and endotoxin levels tended to be elevated in dialysate, with the highest levels of endotoxin in dialysates posing an obvious potential risk when high-flux dialyzers are used.

Pain and compression neuropathy in primary inguinal hernia

PURPOSE

Enlargement of the ilioinguinal nerve at the external inguinal ring is observed in 34% of patients undergoing primary open inguinal herniorrhaphy; in 88% of patients it occurs at the fascial edge where the hernia mushrooms with abdominal pressure. Compression neuropathy occurs near many anatomical nerve constriction sites and is associated with enlargement of the peripheral nerve accompanied by sensory changes.

METHODS

In this prospective study, Carolina Comfort Scale (CCS) questionnaire data was collected for 35 primary hernia repairs. Each patient underwent primary inguinal herniorrhaphy that included ilioinguinal neurectomy. All nerves were sampled proximal to the external inguinal ring. Any nerves with grossly increased overall diameter to any degree distal to the external ring were additionally sampled in the thickened portions. A neuropathologist performed histologic evaluation of the H&E-stained cross sections.

RESULTS

Paired comparison of proximal and distal nerves revealed a greater overall diameter and greater measured nerve-specific diameter in distal nerve segments. Nerves with increased overall diameter were also found to have a statistically significant positive correlation with four of eight pain measures. Additionally, increased nerve-specific diameter correlates with increased pain on four of eight pain values, but age effect on nerve diameter blunts this finding.

CONCLUSIONS

Increased preoperative CCS pain values in primary open inguinal hernia are significantly correlated with gross enlargement of the overall diameter and nerve-specific diameter of the ilioinguinal nerve beyond the external inguinal ring. This is consistent with a compression neuropathy.

Smoking, HIV, and risk of pregnancy loss

OBJECTIVE

Cigarette smoking during pregnancy increases risks of poor pregnancy outcomes including miscarriage and stillbirth (pregnancy loss), but the effect of smoking on pregnancy loss among HIV-infected women has not been explored. Here, investigated the impact of smoking on risk of pregnancy loss among HIV-positive and HIV-negative women, and estimated the potential impact of realistic smoking cessation interventions on risk of pregnancy loss among HIV-positive women.

DESIGN

We analyzed pregnancy outcomes in HIV-positive and HIV-negative participants in the Women's Interagency HIV Study between 1994 and 2014.

METHODS

We estimated effects of current smoking at or immediately before pregnancy on pregnancy loss; we controlled for confounding using regression approaches, and estimated potential impact of realistic smoking cessation interventions using a semiparametric g-formula approach.

RESULTS

Analysis examined 1033 pregnancies among 659 women. The effect of smoking on pregnancy loss differed dramatically by HIV status: adjusted for confounding, the risk difference comparing current smokers to current nonsmokers was 19.2% (95% confidence limit 10.9-27.5%) in HIV-positive women and 9.7% (95% confidence limit 0.0-19.4%) in HIV-negative women. These results were robust to sensitivity analyses. We estimated that we would need to offer a realistic smoking cessation intervention to 36 women to prevent one pregnancy loss.

CONCLUSION

Smoking is a highly prevalent exposure with important consequences for pregnancy in HIV-positive pregnant women in the United States, even in the presence of potent highly active antiretroviral therapy. This evidence supports greater efforts to promote smoking cessation interventions among HIV-positive women, especially those who desire to become pregnant.

Trends of and factors associated with live-birth and abortion rates among HIV-positive and HIV-negative women

BACKGROUND

Little is known about fertility choices and pregnancy outcome rates among HIV-infected women in the current combination antiretroviral treatment era.

OBJECTIVE

We sought to describe trends and factors associated with live-birth and abortion rates among HIV-positive and high-risk HIV-negative women enrolled in the Women's Interagency HIV Study in the United States.

STUDY DESIGN

We analyzed longitudinal data collected from Oct. 1, 1994, through Sept. 30, 2012, through the Women's Interagency HIV Study. Age-adjusted rates per 100 person-years live births and induced abortions were calculated by HIV serostatus over 4 time periods. Poisson mixed effects models containing variables associated with live births and abortions in bivariable analyses (P < .05) generated adjusted incidence rate ratios and 95% confidence intervals.

RESULTS

There were 1356 pregnancies among 2414 women. Among HIV-positive women, age-adjusted rates of live birth increased from 1994 through 1997 to 2006 through 2012 (2.85-7.27/100 person-years, P trend < .0001). Age-adjusted rates of abortion in HIV-positive women remained stable over these time periods (4.03-4.29/100 person-years, P trend = .09). Significantly lower live-birth rates occurred among HIV-positive compared to HIV-negative women in 1994 through 1997 and 1997 through 2001, however rates were similar during 2002 through 2005 and 2006 through 2012. Higher CD4+ T cells/mm3 (≥350 adjusted incidence rate ratio, 1.39 [95% CI 1.03-1.89] vs <350) were significantly associated with increased live-birth rates, while combination antiretroviral treatment use (adjusted incidence rate ratio, 1.35 [95% CI 0.99-1.83]) was marginally associated with increased live-birth rates. Younger age, having a prior abortion, condom use, and increased parity were associated with increased abortion rates among both HIV-positive and HIV-negative women. CD4+ T-cell count, combination antiretroviral treatment use, and viral load were not associated with abortion rates.

CONCLUSION

Unlike earlier periods (pre-2001) when live-birth rates were lower among HIV-positive women, rates are now similar to HIV-negative women, potentially due to improved health status and combination antiretroviral treatment. Abortion rates remain unchanged, illuminating a need to improve contraceptive services.

Minimal important improvement thresholds for the six-minute walk test in a knee arthroplasty cohort: triangulation of anchor- and distribution-based methods

Background

The 6-minute walk test (6MWT) is a commonly used metric for measuring change in mobility after knee arthroplasty, however, what is considered an improvement after surgery has not been defined. The determination of important change in an outcome assessment tool is controversial and may require more than one approach. This study, nested within a combined randomised and observational trial, aimed to define a minimal important improvement threshold for the 6MWT in a knee arthroplasty cohort through a triangulation of methods including patient-perceived anchor-based thresholds and distribution-based thresholds.

Methods

Individuals with osteoarthritis performed a 6MWT pre-arthroplasty then at 10 and 26 weeks post-surgery. Each rated their perceived improvement in mobility post-surgery on a 7-point transition scale anchored from “much better” to “much worse”. Based on these responses the cohort was dichotomised into ‘improved’ and ‘not improved’. The thresholds for patient-perceived improvements were then identified using two receiver operating curve methods producing sensitivity and specificity indices. Distribution-based change thresholds were determined using two methods utilising effect size (ES). Agreement between the anchor- and distribution-based methods was assessed using kappa.

Results

One hundred fifty-eight from 166 participants in the randomised cohort and 222 from 243 in the combined randomised and observational cohort were included at 10 and 26 weeks, respectively. The slightly or more patient-perceived improvement threshold at 26 weeks (an absolute improvement of 26 m) was the only one to demonstrate sensitivity and specificity results both better than chance. At 10- and 26-weeks, the ES based on the mean change score divided by the baseline standard deviation (SD), was an absolute change of 24.5 and 37.9 m, respectively. The threshold based on a moderate ES (a 0.5 SD of the baseline score) was a change of 55.0 and 55.4 m at 10- and 26-weeks, respectively. The level of agreement between the 26-week anchor-based and distribution-based minimal absolute changes was very good (k = 0.88 (95 % CI 0.81 0.95)).

Conclusion

A valid threshold of improvement for the 6MWT can only be proposed for changes identified from baseline to 26 weeks post-surgery. The level of agreement between anchor- and distribution-based methods indicates that a true minimal or more threshold of meaningful improvement following surgery is likely within the ranges proposed by the triangulation of all four methods, that is, 26 to 55 m.

Early-life metal exposure and schizophrenia: A proof-of-concept study using novel tooth-matrix biomarkers

BACKGROUND

Despite evidence for the effects of metals on neurodevelopment, the long-term effects on mental health remain unclear due to methodological limitations. Our objective was to determine the feasibility of studying metal exposure during critical neurodevelopmental periods and to explore the association between early-life metal exposure and adult schizophrenia.

METHODS

We analyzed childhood-shed teeth from nine individuals with schizophrenia and five healthy controls. We investigated the association between exposure to lead (Pb(2+)), manganese (Mn(2+)), cadmium (Cd(2+)), copper (Cu(2+)), magnesium (Mg(2+)), and zinc (Zn(2+)), and schizophrenia, psychotic experiences, and intelligence quotient (IQ). We reconstructed the dose and timing of early-life metal exposures using laser ablation inductively coupled plasma mass spectrometry.

RESULTS

We found higher early-life Pb(2+) exposure among patients with schizophrenia than controls. The differences in log Mn(2+) and log Cu(2+) changed relatively linearly over time to postnatal negative values. There was a positive correlation between early-life Pb(2+) levels and psychotic experiences in adulthood. Moreover, we found a negative correlation between Pb(2+) levels and adult IQ.

CONCLUSIONS

In our proof-of-concept study, using tooth-matrix biomarker that provides direct measurement of exposure in the fetus and newborn, we provide support for the role of metal exposure during critical neurodevelopmental periods in psychosis.

Construction of a fetal spatio-temporal cortical surface atlas from in utero MRI: Application of spectral surface matching

In this study, we construct a spatio-temporal surface atlas of the developing cerebral cortex, which is an important tool for analysing and understanding normal and abnormal cortical development. In utero Magnetic Resonance Imaging (MRI) of 80 healthy fetuses was performed, with a gestational age range of 21.7 to 38.9 weeks. Topologically correct cortical surface models were extracted from reconstructed 3D MRI volumes. Accurate correspondences were obtained by applying a joint spectral analysis to cortices for sets of subjects close to a specific age. Sulcal alignment was found to be accurate in comparison to spherical demons, a state of the art registration technique for aligning 2D cortical representations (average Fréchet distance≈0.4 mm at 30 weeks). We construct consistent, unbiased average cortical surface templates, for each week of gestation, from age-matched groups of surfaces by applying kernel regression in the spectral domain. These were found to accurately capture the average cortical shape of individuals within the cohort, suggesting a good alignment of cortical geometry. Each spectral embedding and its corresponding cortical surface template provide a dual reference space where cortical geometry is aligned and a vertex-wise morphometric analysis can be undertaken.

Incidence of cervical precancers among HIV-seropositive women

OBJECTIVE

The objective of the study was to estimate the impact of human immunodeficiency virus (HIV) infection on the incidence of high-grade cervical intraepithelial neoplasia (CIN).

STUDY DESIGN

HIV-seropositive and comparison seronegative women enrolled in a prospective US cohort study were followed up with semiannual Papanicolaou testing, with colposcopy for any abnormality. Histology results were retrieved to identify CIN3+ (CIN3, adenocarcinoma in situ, and cancer) and CIN2+ (CIN2 and CIN3+). Annual detection rates were calculated and risks compared using a Cox analysis. Median follow-up (interquartile range) was 11.0 (5.4-17.2) years for HIV-seronegative and 9.9 (2.5-16.0) for HIV-seropositive women.

RESULTS

CIN3+ was diagnosed in 139 HIV-seropositive (5%) and 19 HIV-seronegative women (2%) (P<.0001), with CIN2+ in 316 (12%) and 34 (4%) (P<.0001). The annual CIN3+ detection rate was 0.6 per 100 person-years in HIV-seropositive women and 0.2 per 100 person-years in seronegative women (P<.0001). The CIN3+ detection rate fell after the first 2 years of study, from 0.9 per 100 person-years among HIV-seropositive women to 0.4 per 100 person-years during subsequent follow-up (P<.0001). CIN2+ incidence among these women fell similarly with time, from 2.5 per 100 person-years during the first 2 years after enrollment to 0.9 per 100 person-years subsequently (P<.0001). In Cox analyses controlling for age, the hazard ratio for HIV-seropositive women with CD4 counts less than 200/cmm compared with HIV-seronegative women was 8.1 (95% confidence interval, 4.8-13.8) for CIN3+ and 9.3 (95% confidence interval, 6.3-13.7) for CIN2+ (P<.0001).

CONCLUSION

Although HIV-seropositive women have more CIN3+ than HIV-seronegative women, CIN3+ is uncommon and becomes even less frequent after the initiation of regular cervical screening.

Accuracy of colposcopy in HIV seropositive and seronegative women with abnormal Pap tests

OBJECTIVE

The aim of this study is to compare colposcopic findings and the accuracy of colposcopic impression in HIV seropositive and seronegative women with abnormal Pap tests.

METHODS

HIV seropositive and seronegative women in a national cohort study had Pap tests collected every six months, with colposcopy for any abnormal result. Prospectively collected colposcopy and histology findings were analyzed retrospectively using Pearson Chi-square, t-test and Wilcoxon two-sample tests, logistic regression models, and Kappa coefficients.

RESULTS

After adjusting for age and Pap result, 1618 eligible HIV seropositive women were more likely than 406 seronegative women to have inadequate colposcopic examinations, abnormal colposcopic findings, and large cervical lesions. However, among those with abnormal colposcopy, colposcopic characteristics and lesion size and number did not differ by HIV serostatus. Agreement between colposcopists' impressions and highest grade biopsy diagnoses was fair (kappa coefficient 0.35, 95% C.I. 0.31, 0.38). Agreement did not differ by HIV serostatus and did not improve with multiple biopsies (weighted kappa coefficient 0.35, 95% C.I. 0.32, 0.39) or after including all histology results over two years following colposcopy.

CONCLUSION

Although HIV seropositive women with abnormal cytology are more likely to have colposcopic abnormality, the performance of colposcopy appears to be similar to that in HIV seronegative women. Biopsy is required to confirm colposcopic impression.

Total and unbound darunavir pharmacokinetics in pregnant women infected with HIV-1: results of a study of darunavir/ritonavir 600/100 mg administered twice daily

Objectives

Antiretroviral therapy during pregnancy is recommended to reduce the risk of mother-to-child transmission of HIV and for maternal care management. Physiological changes during pregnancy can affect pharmacokinetics, potentially altering pharmacological activity. We therefore evaluated the pharmacokinetics of twice-daily (bid) darunavir in HIV-1-infected pregnant women.

Methods

HIV-1-infected pregnant women receiving an antiretroviral regimen containing darunavir/ritonavir 600/100 mg bid were enrolled in this study. Total and unbound darunavir and total ritonavir plasma concentrations were obtained over 12 h during the second and third trimesters and postpartum. Total darunavir and ritonavir plasma concentrations were determined using a validated high-performance liquid chromatography tandem mass spectrometry assay and unbound darunavir was determined using ¹⁴C-darunavir-fortified plasma. Pharmacokinetic parameters were derived using noncompartmental analysis.

Results

Data were available for 14 women. The area under the plasma concentration–time curve from 0 to 12 h (AUC_12h) for total darunavir was 17–24% lower during pregnancy than postpartum. The AUC_12h for unbound darunavir was minimally reduced during pregnancy vs. postpartum. The minimum plasma concentration (C_min) of total and unbound darunavir was on average 43–86% and 10–14% higher, respectively, during pregnancy vs. postpartum. The antiviral response (< 50 HIV-1 RNA copies/mL) was 33% at baseline and increased to 73–90% during treatment; the percentage CD4 count increased over time. One serious adverse event was reported (increased transaminase). All 12 infants born to women remaining in the study at delivery were HIV-1-negative; four of these infants were premature.

Conclusions

Total darunavir exposure decreased during pregnancy. No clinically relevant change in unbound (active) darunavir occurred during pregnancy, suggesting that no dose adjustment is required for darunavir/ritonavir 600/100 mg bid in pregnant women.

Structural changes in freshwater fish and chironomids exposed to bacterial exotoxins

Mass fish mortalities have been reported in the past decade from British waters, often coinciding with blooms of filamentous actinobacteria, particularly strains of Streptomyces griseus. The present study has shown that some fractions of the exudate of S. griseus, prepared after a series of high pressure liquid chromatography (HPLC) separations, and analysed with liquid chromatography mass spectrometry (LC-MS), induced pathological changes to the gills of carp and/or tench fry following exposure under laboratory conditions up to 96 h Similar changes were induced by streptomycin, a secondary metabolite of S. griseus, and these included loss of microridging and fusion of secondary lamellae, with carp fry in the case of the exudate of S. griseus being more sensitive than tench fry, especially with exposure to fraction 9 and selected sub-fractions of 9. Some deformities using a severity index were also observed in the head capsule of larvae of the non-biting midge Chironomus riparius, including loss and splitting of teeth on the mentum. The results are discussed in relation to further identification of metabolites derived from samples of the organic filtrate of S. griseus and implications for the functioning of freshwater ecosystems.

Lipid and endothelium-related genes, ambient particulate matter, and heart rate variability--the VA Normative Aging Study

BACKGROUND

Many studies have shown that exposures to air pollution are associated with cardiovascular events, although the mechanism remains to be clarified. To identify whether exposures to ambient particles act on autonomic function via the lipid/endothelial metabolism pathway, whether effects of particulate matter <2.5 mum in aerodynamic diameter (PM(2.5)) on heart rate variability (HRV) were modified by gene polymorphisms related to those pathways were evaluated.

METHODS

HRV and gene data from the Normative Aging Study and PM(2.5) from a monitor located a kilometre from the examination site were used. A mixed model was fitted to investigate the associations between PM(2.5) and repeated measurements of HRV by gene polymorphisms of apolipoprotein E (APOE), lipoprotein lipase (LPL) and vascular endothelial growth factor (VEGF) adjusting for potential confounders chosen a priori.

RESULTS

A 10 microg/m(3) increase in PM(2.5) in the 2 days before the examination was associated with 3.8% (95% CI 0.2% to 7.4%), 7.8% (95 CI 0.4% to 15.3%) and 10.6% (95% CI 1.8% to 19.4%) decreases of the standard deviation of normal-to-normal intervals, the low frequency and the high frequency, respectively. Overall, carriers of wild-type APOE, LPL and VEGF genes had stronger effects of particles on HRV than those with hetero- or homozygous types. Variations of LPL-N291S, LPL-D9N and APOE-G113C significantly modified effects of PM(2.5) on HRV.

CONCLUSION

Associations between PM(2.5) and HRV were modified by gene polymorphisms of APOE, LPL and VEGF; the biological metabolism remains to be identified.

Mass mortality and its environmental and evolutionary consequences

The latest Mesozoic and earliest Tertiary sediments at Deep Sea Drilling Project site 524 provide an amplified record of environmental and biostratographic changes at the end of Cretaceous. Closely spaced samples, representing time intervals as short as 10(2) or 10(3) years, were analyzed for their bulk carbonate and trace-metal compositions, and for oxygen and carbon isotopic compositions. The data indicate that at the end of Cretaceous, when a high proportion of the ocean's planktic organisms were eliminated, an associated reduction in productivity led to a partial transfer of dissolved carbon dioxide from the oceans to the atmosphere. This resulted in a large increase of the atmospheric carbon dioxide during the next 50,000 years, which is believed to have caused a temperature rise revealed by the oxygen-isotope data. The lowermost Tertiary sediments at site 524 include fossils with Cretaceous affinities, which may include both reworked individuals and some forms that survived for a while after the catastrophe. Our data indicate that many of the Cretaceous pelagic organisms became extinct over a period of a few tens of thousands of years, and do not contradict the scenario of cometary impact as a cause of mass mortality in the oceans, as suggested by an iridium anomaly at the Cretaceous-Tertiary boundary.

Toxic effects of Streptomyces griseus spores and exudate on gill pathology of freshwater fish

Many unexplained fish-kills in British waters are considered microbial in origin and a large proportion of field sites contains elevated concentrations of filamentous actinobacteria. The present study has shown that a strain of Streptomyces griseus, isolated from field sites, elicits pathological changes to the gills of fish under laboratory conditions which mirror those found in situ. These changes include hyperplasia leading to fusion of the secondary lamellae and loss of microridging on the filamental epithelium of the primary lamellae. Juveniles of up to six fish species were exposed to spore suspensions or exudate of S. griseus in the range of 1 x 10(2)-1 x 10(6)spores ml(-1) for up to 96 h. The exudate was more potent than the spores and there was a positive correlation between exudate concentration and the rate and extent of fish gill pathology with bream and rainbow trout being more sensitive than carp, tench and roach. The results are discussed in the context of recognising and managing potential fish mortalities caused by microbial toxins.

HLA A and B locus antigens in patients with unexplained hepatitis following halothane anaesthesia

HLA A and B locus antigens were determined in 17 patients who had recovered from unexplained hepatitis following halothane anaesthesia. The greatest deviations from expected frequencies were observed with A1, A11 and BW22, but these differences were not statistically significant when the P values were corrected for the number of antigens tested. Although a larger series might show such deviations to be significantly different, HLA typing is of no predictive value in determining those at risk to hepatitis following repeated halothane exposure.

Suppression of HOX A cluster genes inhibits proliferation and induces cell death in human mixed-lineage leukemias

14020

Background: Leukemias harboring translocations of the mixed lineage leukemia locus (MLL) are generally associated with poor clinical prognosis. Using gene expression profiling we and others have previously shown that Homeobox (HOX) A cluster genes are highly expressed in leukemias with MLL rearrangements. Methods: Here we studied the role of aberrant HOXA9 expression in human MLL- rearranged and non-rearranged leukemias utilizing an shRNA mediated knockdown approach. Results: Three different shRNA constructs targeting human HOXA9 were synthesized and stably introduced into t(9;11) MOLM14 cells utilizing a lentiviral vector system. 75–80% HOXA9 RNA knockdown was confirmed by quantitative PCR and Western Blot analysis. In a panel of 17 AML/ALL cell lines (7 MLL rearranged, 10 non rearranged), HOXA9 directed shRNA inhibited cell proliferation starting as early as 48h after transduction, and induced apoptosis beginning at 72h. Interestingly, impaired cell proliferation and induction of apoptosis was significantly higher in the MLL rearranged cell lines (mean viability: 51.88%) than in the non-rearranged cells (mean viability: 90.98%; p=0.007) and also significantly correlated with the baseline HOXA9 mRNA expression before knockdown (R= 0.8, p=0.00017). We then further analyzed the effect of HOXA9 knockdown in MLL rearranged and non-rearranged primary human AML cells. Similar to our findings in cell lines, a marked induction of cell death was observed, which was significantly higher in leukemias with an MLL translocation (p=0.005) and also significantly correlated with the baseline HOXA9 mRNA expression (R= 0.8, p=0.001). Next, the in vivo effect of HOXA9 knockdown was assessed by transplanting luciferase-expressing SEMK2 (t4;11) cells into SCID-beige mice followed by in vivo bioluminescent imaging. Leukemia burden was significantly reduced in HOXA9 shRNA treated mice (n=10) with a peak difference at day 15 (p=0.000059) shortly before mice of the control group (n=10) succumbed from overt leukemia. At this point all mice of the HOXA9 shRNA treated group were still healthy with no signs of leukemia. Conclusions: Taken together our data implicates that depletion of HOXA9 might be a novel approach for targeted therapy in human MLL rearranged leukemias.

No significant financial relationships to disclose.

Lisfranc injury in a national hockey league player: a case report

Tarsometatarsal joint dislocations and fracture-dislocations are uncommon injuries most frequently resulting from high-energy trauma as encountered in crush injuries, falls, and motor vehicle accidents. Although less common in athletes, this injury is being recognized with greater frequency and may carry a poor prognosis for return to high levels of competition. These injuries present a considerable challenge to orthopedic surgeons caring for athletes because of the prolonged period of recovery often required [ 1,2,5,6,12]. The literature contains descriptions of this injury in football players, gymnasts, tennis players, and track and field athletes [2,5,9]. To our knowledge, no report of such a Lisfranc injury to a hockey player has been described. This is a case report of a National Hockey League player that sustained a Lisfranc injury requiring surgical stabilization, but was able to return to elite hockey play.