Vendor-Neutral Right Ventricular Strain Measurement

OBJECTIVE

To test the feasibility and reliability of using a vendor-neutral platform to evaluate right ventricular (RV) strain. Reliability was determined by comparing intra- and inter-observer variability between RV strain assessments. The secondary objective was to assess strain's correlation with conventional RV functional parameters to evaluate its feasibility as a RV systolic functional assessment tool.

DESIGN

This is a retrospective study.

SETTING

Tertiary hospital.

PARTICIPANTS

A total of 15 patients who underwent elective coronary artery bypass graft surgery were selected for inclusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Images obtained during routine, intraoperative, two-dimensional transesophageal echocardiography (2D TEE) were assessed for longitudinal strain (LS) and conventional parameters, including fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), Doppler tissue imaging (DTI)-derived tricuspid lateral annular systolic velocity wave (S'), and RV dimensions using vendor-neutral software. There was good to excellent intra- and inter-observer reproducibility (intraclass correlation coefficient [ICC] from 0.75 to 1.00) with the exception of basal free wall longitudinal strain (FWLS) (for intra- and inter-observer reproducibility, ICC = 0.670 and 0.749, respectively). FWLS and global longitudinal strain (GLS) showed moderate to strong positive correlation with FAC, TAPSE, and S' (correlation coefficients from 0.667 to 0.721).

CONCLUSION

It is feasible to assess RV strain across multiple platforms in a reproducible and reliable fashion. Furthermore, RV strain demonstrated good correlation with conventional RV functional parameters, suggesting its feasibility as a sensitive RV function assessment tool.

Subtalar coalition resection utilizing live navigation: a technique tip

PURPOSE

Describe the surgical technique of talocalcaneal coalition resection using live CT navigation.

METHODS

A ten-year-old female with left talocalcaneal coalition hindfoot pain refractory to conservative management underwent surgical coalition resection using live CT navigation. The procedure and discussion of this technique is described in detail.

RESULTS

With minimal radiation exposure to the patient, CT navigation for this complex talocalcaneal coalition was both helpful and potentially timesaving by allowing immediate localization and guided resection of the coalition.

CONCLUSION

In the case of a complex subtalar coalition resection, CT navigation poses minimal patient radiation exposure and allows immediate localization and guided resection of the coalition.

LEVEL OF EVIDENCE

Level V.

Sofosbuvir and daclatasvir therapy in patients with hepatitis C-related advanced decompensated liver disease (MELD ≥ 15)

BACKGROUND

Antiviral therapy for hepatitis C has the potential to improve liver function in patients with decompensated cirrhosis.

AIMS

To examine the virological response and effect of viral clearance in patients with decompensated hepatitis C cirrhosis all with MELD scores ≥15 following sofosbuvir/daclatasvir ± ribavirin.

METHODS

We prospectively collected data on patients who commenced sofosbuvir/daclatasvir for 24-weeks under the Australian patient supply program (TOSCAR) and analysed outcomes including sustained viral response at 12 weeks (SVR12), death and transplant.

RESULTS

108 patients (M/F, 79/29; median age 56years; Child-Pugh 10; MELD 16; genotype 1/3, 55/47) received sofosbuvir/daclatasvir and two also received ribavirin. On intention-to-treat, the SVR12 rate was 70% (76/108). Seventy-eight patients completed 24-weeks therapy. SVR12 was achieved in 56 of these patients on per-protocol-analysis (76%). SVR12 was 80% in genotype 1 compared to 69% in genotype 3. Thirty patients failed to complete therapy. In patients achieving SVR12, median MELD and Child-Pugh fell from 16(IQR15-17) to 14(12-17) and 10(9-11) to 8(7-9), respectively (P<.001). In those who died, MELD increased from 16 to 23 at death (P=.036). Patients who required transplantation had a significantly higher baseline MELD (20) compared to those patients completing treatment (16) (P=.0010). The odds ratio for transplant in patients with baseline MELD ≥20 was 13.8(95%CI 2.78-69.04).

CONCLUSIONS

SVR12 rates with sofosbuvir/daclatasvir in advanced liver disease are lower than in compensated disease. Although treatment improves MELD and Child-Pugh in most patients, a significant proportion will die or require transplantation. In those with MELD ≥20, it may be better to delay treatment until post-transplant.

Validation of a low field Rheo-NMR instrument and application to shear-induced migration of suspended non-colloidal particles in Couette flow

Nuclear magnetic resonance rheology (Rheo-NMR) is a valuable tool for studying the transport of suspended non-colloidal particles, important in many commercial processes. The Rheo-NMR imaging technique directly and quantitatively measures fluid displacement as a function of radial position. However, the high field magnets typically used in these experiments are unsuitable for the industrial environment and significantly hinder the measurement of shear stress. We introduce a low field Rheo-NMR instrument (¹H resonance frequency of 10.7MHz), which is portable and suitable as a process monitoring tool. This system is applied to the measurement of steady-state velocity profiles of a Newtonian carrier fluid suspending neutrally-buoyant non-colloidal particles at a range of concentrations. The large particle size (diameter >200μm) in the system studied requires a wide-gap Couette geometry and the local rheology was expected to be controlled by shear-induced particle migration. The low-field results are validated against high field Rheo-NMR measurements of consistent samples at matched shear rates. Additionally, it is demonstrated that existing models for particle migration fail to adequately describe the solid volume fractions measured in these systems, highlighting the need for improvement. The low field implementation of Rheo-NMR is complementary to shear stress rheology, such that the two techniques could be combined in a single instrument.

Pregnancy is detected via odour in a wild cooperative breeder

Among mammals, scent has long been known to encode oestrus; however, in many species, detecting pregnancy may also be important in terms of both competition and mate-choice. Here, we show, through odour presentation experiments, that pregnancy is discernible via scent by both sexes in the cooperatively breeding banded mongoose, Mungos mungo Males spent more time investigating and were more likely to scent mark the odours of non-pregnant females, compared to pregnant females. Females showed increased levels of scent marking when odours were of the same reproductive state as themselves. These results present the first direct demonstration that pregnancy is detectable via scent in wild cooperative breeders. Detecting pregnancy may be particularly important in cooperative breeders as, in addition to the competition between males for receptive mates, there is also intense competition between females for access to alloparental care. Consequently, dominant females benefit from targeting reproductive suppression towards subordinates that represent direct threats, such as pregnant females.

Amazon plant diversity revealed by a taxonomically verified species list

Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests.

Oral Dosage Forms that should not be Crushed or Chewed

The 2002 update of the Hospital Pharmacy feature “Oral Dosage Forms that Should Not Be Crushed or Chewed” is included with this issue as a wall chart.

The SMA Trust: the role of a disease-focused research charity in developing treatments for SMA

SMA is a rare hereditary neuromuscular disease that causes weakness and muscle wasting as a result of the loss of spinal motor neurons. In its most severe form, SMA is the commonest genetic cause of death in infants, and children with less severe forms of SMA face the prospect of lifelong disability from progressive muscle wasting, loss of mobility and limb weakness. The initial discovery of the defective gene has been followed by major advances in our understanding of the genetic, cellular and molecular basis of SMA, providing the foundation for a range of approaches to treatment, including gene therapy, antisense oligonucleotide treatments and more traditional drug-based approaches to slow or halt disease progression. The approval by the US Food and Drug Administration (FDA) of Spinraza (nusinersen), the first targeted treatment for spinal muscular atrophy (SMA), is a historic moment. Disease-focused research charities, such as The SMA Trust (UK), continue to have a crucial role in promoting the development of additional treatments for SMA, both by funding translational research and by promoting links between researchers, people living with SMA and other stakeholders, including pharmaceutical companies and healthcare providers.

Antigen-presenting tumor B cells impact the phenotype of CD4 tumor infiltrating T cells in lung cancer patients

The focus of immunotherapy has been on CD8 and CD4 tumor infiltrating lymphocytes (TILs), however, tumor infiltrating B cells (TIL-Bs) are understudied with no focus on their role as antigen presenting cells. We hypothesize that TIL-Bs help generate potent, long-term immune responses against cancer by presenting tumor antigens to CD4 TILs.

Using un-manipulated, primary human B cells from fresh tumor, we generated a specific in vitro antigen presentation assay and observed three types of CD4 TIL responses when TIL-Bs presented autologous tumor antigens. There were activated responder CD4 TILs that proliferated when combined with TIL-Bs alone, which indicates stimulation with endogenous tumor antigens. There were antigen-associated responders that required autologous tumor lysate to elicit a CD4 TIL response, and there were patient CD4 TILs that did not respond to antigen presentation. Exhausted B cells have been described in chronic infection i.e. HIV, and thus, to parallel our studies to a model of chronic infection, we analyzed activated and exhausted TIL-Bs with our antigen presentation assay. If TIL-Bs were activated (HLADR+CD69+CD27+CD21+), the resultant CD4 TILs were T helper (anti-tumor) CD4 T cells and if the TIL-Bs were exhausted (HLADR+CD69+CD27−CD21−), the resultant CD4 TILs were T regulatory cells (pro-tumor). These data suggest that TIL-Bs influence CD4 TILs in NSCLC patient tumors.

In conclusion, determining if TIL-Bs are activated or exhausted in NSCLC patients will determine the extent of their anti-tumor function in human cancer. Ultimately, results from this study will dictate how to target TIL-Bs in future immunotherapies.

Assessing the use of 4DCT-ventilation in pre-operative surgical lung cancer evaluation

PURPOSE

A primary treatment option for lung cancer patients is surgical resection. Patients who have poor lung function prior to surgery are at increased risk of developing serious and life-threatening complications after surgical resection. Surgeons use nuclear medicine ventilation-perfusion (VQ) scans along with pulmonary function test (PFT) information to assess a patient's pre-surgical lung function. The nuclear medicine images and pre-surgery PFTs are used to calculate percent predicted postoperative (%PPO) PFT values by estimating the amount of functioning lung tissue that would be lost with surgical resection. Nuclear medicine imaging is currently considered the standard of care when evaluating the amount of ventilation that would be lost due to surgery. A novel lung function imaging modality has been developed in radiation oncology that uses 4-Dimensional computed tomography data to calculate ventilation maps (4DCT-ventilation). Compared to nuclear medicine, 4DCT-ventilation is cheaper, does not require a radioactive contrast agent, provides a faster imaging procedure, and has improved spatial resolution. In this work we perform a retrospective study to assess the use of 4DCT-ventilation as a pre-operative surgical lung function evaluation tool. Specifically, the purpose of our study was to compare %PPO PFT values calculated with 4DCT-ventilation and %PPO PFT values calculated with nuclear medicine ventilation-perfusion imaging.

METHODS

The study included 16 lung cancer patients that had undergone 4DCT imaging, nuclear medicine imaging, and had Forced Expiratory Volume in 1 second (FEV₁ ) acquired as part of a standard PFT. The 4DCT datasets, spatial registration, and a density-change-based model were used to compute 4DCT-ventilation maps. Both 4DCT-ventilation and nuclear medicine images were used to calculate %PPO FEV₁ . The %PPO FEV₁ was calculated by scaling the pre-surgical FEV₁ by (1-fraction of total resected ventilation); where the resected ventilation was determined using either the 4DCT-ventilation or nuclear medicine imaging. Calculations were done assuming both lobectomy and pneumonectomy resections. The %PPO FEV₁ values were compared between the 4DCT-ventilation-based calculations and the nuclear medicine-based calculations using correlation coefficients, average differences, and Receiver Operating Characteristic (ROC) analysis.

RESULTS

Overall the 4DCT-ventilation derived %PPO FEV₁ values agreed well with nuclear medicine-derived %PPO FEV₁ data with correlations of 0.99 and 0.81 for lobectomy and pneumonectomy, respectively. The average differences between the 4DCT-ventilation and nuclear medicine-based calculation for %PPO FEV₁ were less than 5%. ROC analysis revealed predictive accuracy that ranged from 87.5% to 100% when assessing the ability of 4DCT-ventilation to predict for nuclear medicine-based %PPO FEV₁ values.

CONCLUSIONS

4DCT-ventilation is an innovative technology developed in radiation oncology that has great potential to translate to the surgical domain. The high correlation results when comparing 4DCT-ventilation to the current standard of care provide a strong rationale for a prospective clinical trial assessing 4DCT-ventilation in the clinical setting. 4DCT-ventilation can reduce the cost and imaging time for patients while providing improved spatial accuracy and quantitative results for surgeons.

Persistence analysis of poliovirus on three different types of fomites

AIMS

The goal of this study was to explore various models for describing viral persistence (infectivity) on fomites and identify the best fit models.

METHODS AND RESULTS

The persistence of poliovirus over time was studied on three different fomite materials: steel, cotton and plastic. Known concentrations of poliovirus type 1 were applied to the surface coupons in an indoor environment for various lengths of time. Viruses were recovered from the surfaces by vortexing in phosphate buffer. Seven different mathematical models of relative persistence over time were fit to the data, and the preferred model for each surface was selected based on the Bayesian information criterion.

CONCLUSIONS

While the preferred model varied by fomite type, the virus showed a rapid initial decay on all of the fomite types, followed by a transition to a more gradual decay after about 4-8 days. Estimates of the time for 99% reduction ranged from 81 h for plastic to 143 h for cotton. A 6 log reduction of recoverable infectivity of poliovirus did not occur during the 3-week duration of the experiment for any of the fomites.

SIGNIFICANCE AND IMPACT OF THE STUDY

In protected indoor environments poliovirus can remain infective for weeks. The models identified by this study can be used in risk assessments to identify appropriate strategies for managing this risk.

30-year trends in overweight, obesity and waist-to-height ratio by socioeconomic status in Australian children, 1985 to 2015

BACKGROUND/OBJECTIVE

To report 30-year (1985-2015) prevalence trends in overweight, obesity and abdominal obesity among children by school level and socioeconomic status (SES).

SUBJECTS/METHODS

Five cross-sectional, population child surveys (age 4-18 years; n=27 808) conducted in 1985-1997-2004-2010-2015 in New South Wales, Australia. Outcomes were prevalence of measured overweight, obesity and waist-to-height ratio (WHtR⩾0.5) by sex, school level (children (primary) and adolescents (high)) and SES tertile.

RESULTS

In 2015, the prevalences of overweight, obesity and WHtR⩾0.5 in children were 16.4%, 7.0% and 14.6%, respectively, and in adolescents 21.9%, 17.2% and 4.6%, respectively. Obesity prevalence has not significantly changed in children or adolescents since 1997, nor since 2010 (children, P=0.681; adolescents, P=0.21). Overweight has not significantly changed in children since 1997, but has in adolescents since 1985, with a relative increase of 16 percentage points (P<0.001) between 2010 and 2015. WHtR⩾0.5 prevalence has significantly changed since 1985, except in adolescent girls between 2010 and 2015. Between 2010 and 2015 the relative increase in WHtR⩾0.5 was 17 and 40 percentage points in children and adolescent boys, respectively. Significant disparities in prevalence rates between children and adolescents from low and high SES backgrounds began in 2010 for overweight, since 1997 for obesity and since 2004 for WHtR⩾0.5. Differences between SES groups have become larger over the past 18 years.

CONCLUSIONS

Since 1997, obesity has remained stable, and overweight has stabilized in children, not in adolescents. WHtR⩾0.5 significantly increased between 1985 and 2015, with prevalence rates at each survey around twice the obesity prevalence. Compared with high SES children and adolescents, the risk of overweight, obesity and WHtR⩾0.5 was significantly higher for low SES children and adolescents. The findings are highly relevant to policy makers involved in child obesity prevention interventions and highlight the need for better targeted interventions among children and adolescents from low SES backgrounds, and adolescents in particular.