Functional electrical stimulation (FES)-assisted rowing combined with zoledronic acid, but not alone, preserves distal femur strength and stiffness in people with chronic spinal cord injury

We investigated the effect of 12 months of functional electrical stimulation-assisted rowing with and without zoledronic acid (ZA) on computationally estimated bone strength and stiffness in individuals with spinal cord injury. We found that rowing with ZA, but not rowing alone, improved stiffness at the distal femur, but not the proximal tibia.

INTRODUCTION

People with spinal cord injury (SCI) have high fracture risk at the knee after the injury. Therapies that prevent bone loss or stimulate an anabolic response in bone have been proposed to reduce fractures. Zoledronic acid (ZA) is a potent bisphosphonate that inhibits osteoclastic resorption. Functional electrical stimulation (FES)-assisted rowing is a potentially osteogenic exercise involving mechanical stimulation to the lower extremities. Here, we investigated the effect of FES-assisted rowing with and without ZA on bone strength and stiffness in individuals with SCI.

METHODS

Twenty individuals from a cohort of adults with SCI who participated in a clinical trial were included in the study. CT scans of their knees before and after the intervention were converted to finite element models. Bone failure strength (T_ult) and stiffness were calculated at the proximal tibia and distal femur.

RESULTS

T_ult at the distal femur increased 4.6% among people who received rowing + ZA and decreased 13.9% among those with rowing only (p < 0.05 for group). Torsional and compressive stiffness at the femur metaphysis increased in people with rowing + ZA (+ 3 to +4%) and decreased in people with rowing only (- 7 to -8%; p < 0.05). T_ult in the proximal tibia decreased in everyone, but the loss was attenuated in the rowing + ZA group. People with initially stronger bone tended to lose more strength.

CONCLUSION

Overall, we observed increases in bone strength at the distal femur but not the proximal tibia, with FES-assisted rowing combined with ZA treatment. Rowing alone did not significantly prevent bone loss at either site, which might be attributed to insufficient mechanical loading.

Selective beta-3 adrenergic receptor blockade increases contractility of human ventricular trabeculae from HFrEF donors

Background

Alterations of the beta-adrenergic system have been extensively described in the setting of heart failure (HF). Upregulation of beta-3 adrenergic receptor (β3-AdrR) expression in human failing hearts depresses myocardial contractility and, during an acute decompensation event, can be considered a maladaptive compensatory mechanism that exacerbates cardiac dysfunction. APD418 is a selective β3-AdrR antagonist currently in development for patients who have acute heart failure with reduced ejection fraction (HFrEF). APD418 is designed to improve myocardial contractility by selectively antagonizing the β3-AdrR and thereby avoiding the cAMP/Ca2+ signaling pathway stimulated by current inotropes.

Purpose

This study evaluated the effect of a selective β3-AdrR antagonist (APD418) on contractile responses in explanted human ventricular trabeculae obtained from normal and HFrEF hearts.

Methods

Left ventricular trabeculae from normal and HFrEF donors were electrically stimulated (1 Hz) ex-vivo to analyze force generated during contractions. First, BRL37344, a selective β3-AdrR agonist, was applied at increasing concentrations (0.01–10 μM) to confirm β3-AdrR mediated negative inotropy in human myocardial tissue. To test the effect of a selective β3-AdrR antagonist on contractile force, myocardial tissue was pre-treated with APD418 or vehicle for 5 minutes, followed by treatment with non-selective β-AdrR agonists isoproterenol (10 nM) or norepinephrine (5 μM).

Results

In heart tissue from normal donors, the β3-AdrR agonist BRL37344 did not affect contractile function at 0.01 and 0.1 μM. However, in heart tissue from HFrEF donors, BRL37344 induced a significant decrease in contractility at 0.01, 0.1 and 1 μM (85.9±1.8% with 0.1 μM BRL37344 vs 104.1±2.9% with vehicle). Selective blockade of β3-AdrR with APD418 had no effect on force of contraction induced by norepinephrine in cardiac tissue from normal donors. In contrast, APD418 potentiated the force of contraction induced by either isoproterenol (49.1±20.6% increase with 0.1 μM APD418 compared to baseline) or norepinephrine (26.5±4.9% increase with 0.01 μM APD418 compared to baseline) in cardiac tissue from HFrEF patients.

Conclusion

This is, to our knowledge, the first evidence showing that selective blockade of β3-AdrR increases contractility of human ventricular trabeculae from HFrEF donors and suggests that further studies evaluating the therapeutic benefit of APD418 in patients with HFrEF are warranted.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Arena Pharmaceuticals

Obstetric admissions to intensive care units in Australia and New Zealand: a registry-based cohort study

OBJECTIVE

Describe the epidemiology of obstetric patients admitted to an Intensive Care Unit (ICU).

DESIGN

Registry-based cohort study.

SETTING

One hundred and eighty-three ICUs in Australia and New Zealand.

POPULATION

Women aged 15-49 years, admitted to ICU between 2008 and 2017, classified as pregnant, postpartum or with an obstetric-related diagnosis.

METHODS

Data were extracted from the Australia and New Zealand Intensive Care Society (ANZICS) Adult Patient Database and national agencies.

MAIN OUTCOME MEASURES

Incidence of ICU admission, cohort characteristics, maternal outcomes and changes over time.

RESULTS

The cohort comprised 16 063 patients. The annual number of obstetric ICU admissions increased, whereas their proportion of total ICU admissions (1.3%) did not change (odds ratio 1.02, 95% CI 0.99-1.04, P = 0.14). There were 10 518 (65%) with an obstetric-related ICU diagnosis, and 5545 (35%) with a non-obstetric ICU diagnosis. Mean (SD) age was 31 (6.4) years, 1463 (9.1%) were Indigenous, 2305 (14%) were transferred from another hospital, and 3008 (19%) received mechanical ventilation. Median [IQR] length of stay in hospital was 5.2 [3.1-7.9] days, which included 1.1 [0.7-1.8] days in ICU. There were 108 (0.7%) maternal deaths, most (n = 97, 90%) having a non-obstetric diagnosis. There was no change in risk-adjusted length of stay or mortality over time.

CONCLUSIONS

Obstetric patients account for a stable proportion of ICU admissions in Australia and New Zealand. These patients typically have a short length of ICU stay and low hospital mortality.

TWEETABLE ABSTRACT

Obstetric patients in Australia/New Zealand ICUs have a short length of ICU stay and low mortality.

Determination of Low-Level Glucose and Fructose in Raw and Refined Crystalline Sugar by High-Performance Anion-Exchange Chromatography: Collaborative Study

A method was developed and a collaborative study was performed under the auspices of the International Commission of Uniform Methods for Sugar Analysis. The collaborators used high-performance anion-exchange chromatography (HPAEC) to determine trace amounts of glucose and fructose in 3 raw and 3 refined sugar samples provided as blind duplicates. Fourteen laboratories participated in the study. Although difficulties were experienced by a few analysts, 10 laboratories reported positive results. Average repeatabilities and reproducibilities for glucose and fructose in raw sugar were slightly above 5 and 10%, respectively, and the average Horwitz ratios were well under 2. Average repeatabilities and reproducibilities for glucose and fructose in refined sugar were 10 and 22%, respectively; although the Horwitz ratios were &gt;2, they were marginal (2.8). The HPAEC results agreed with results obtained by gas chromatography in an independent laboratory. Because the method was collaboratively studied according to the protocol of the International Union of Pure and Applied Chemistry for collaborative studies, and the results meet its criteria, it is recommended that the method be adopted Official First Action by AOAC INTERNATIONAL.

Longitudinal trajectories of neurocognitive test performance among individuals with perinatal HIV-infection and -exposure: adolescence through young adulthood

There are an estimated 2.1 million youth less than 15 years of age living with HIV globally (the majority perinatally HIV-infected [PHIV]) and millions more perinatally HIV-exposed uninfected (PHEU) youth who are expected to survive through adolescence and into adulthood. Transitioning from adolescence to young adulthood requires adaptation to more demanding social interactions, academic pressures, and individual responsibilities which place distinct demands on neurocognitive functions. This study examined longitudinal trajectories of neurocognitive test performance in the domains of processing speed (PS), working memory (WM), and executive functioning (EF) among PHIV and demographically similar PHEU from adolescence through young adulthood. Data for this paper come from four time points, spanning approximately 10 years, within the Child and Adolescent Self-Awareness and Health Study (CASAH). Youth age ranged from 15 to 29 years. Longitudinal linear mixed effect models were computed for each test. Few differences in performance were found on tests of EF and WM between PHIV and PHEU youth as they aged, though PHEU youth showed significantly better PS as they aged than PHIV youth. Future research is needed to understand these vulnerable youth's neurocognitive trajectories as a function of HIV infection and -exposure, biological functions and psychosocial stressors.

Association between Tumor Acidity and Hypervascularity in Human Gliomas Using pH-Weighted Amine Chemical Exchange Saturation Transfer Echo-Planar Imaging and Dynamic Susceptibility Contrast Perfusion MRI at 3T

BACKGROUND AND PURPOSE

Acidification of the tumor microenvironment from abnormal metabolism along with angiogenesis to meet metabolic demands are both hallmarks of malignant brain tumors; however, the interdependency of tumor acidity and vascularity has not been explored. Therefore, our aim was to investigate the association between pH-sensitive amine chemical exchange saturation transfer echoplanar imaging (CEST-EPI) and relative cerebral blood volume (CBV) measurements obtained from dynamic susceptibility contrast (DSC) perfusion MRI in patients with gliomas.

MATERIALS AND METHODS

In this retrospective study, 90 patients with histologically confirmed gliomas were scanned between 2015 and 2018 (median age, 50.3 years; male/female ratio = 59:31). pH-weighting was obtained using chemical exchange saturation transfer echo-planar imaging estimation of the magnetization transfer ratio asymmetry at 3 ppm, and CBV was estimated using DSC-MR imaging. The voxelwise correlation and patient-wise median value correlation between the magnetization transfer ratio asymmetry at 3 ppm and CBV within T2-hyperintense lesions and contrast-enhancing lesions were evaluated using the Pearson correlation analysis.

RESULTS

General colocalization of elevated perfusion and high acidity was observed in tumors, with local intratumor heterogeneity. For patient-wise analysis, median CBV and magnetization transfer ratio asymmetry at 3 ppm within T2-hyperintense lesions were significantly correlated (R = 0.3180, P = .002), but not in areas of contrast enhancement (P = .52). The positive correlation in T2-hyperintense lesions remained within high-grade gliomas (R = 0.4128, P = .001) and in isocitrate dehydrogenase wild-type gliomas (R = 0.4300, P = .002), but not in World Health Organization II or in isocitrate dehydrogenase mutant tumors. Both magnetization transfer ratio asymmetry at 3 ppm and the voxelwise correlation between magnetization transfer ratio asymmetry and CBV were higher in high-grade gliomas compared with low-grade gliomas in T2-hyperintense tumors (magnetization transfer ratio asymmetry, P = .02; Pearson correlation, P = .01). The same trend held when comparing isocitrate dehydrogenase wild-type gliomas and isocitrate dehydrogenase mutant gliomas (magnetization transfer ratio asymmetry, P = .04; Pearson correlation, P = .01).

CONCLUSIONS

A positive linear correlation between CBV and acidity in areas of T2-hyperintense, nonenhancing tumor, but not enhancing tumor, was observed across patients. Local heterogeneity was observed within individual tumors.

Metastable Nonextremal Antibranes

We find new and compelling evidence for the metastability of supersymmetry-breaking states in holographic backgrounds whose consistency has been the source of ongoing disagreements in the literature. As a concrete example, we analyze anti-D3 branes at the tip of the Klebanov-Strassler throat. Using the blackfold formalism we examine how temperature affects the conjectured metastable state and determine whether and how the existing extremal results generalize when going beyond extremality. In the extremal limit we exactly recover the results of Kachru, Pearson, and Verlinde, in a regime of parameter space that was previously inaccessible. Away from extremality we uncover a metastable black Neveu-Schwarz five-brane (NS5) state that disappears near a geometric transition where black anti-D3 branes and black NS5 branes become indistinguishable. This is remarkably consistent with complementary earlier results based on the analysis of regularity conditions of backreacted solutions. We therefore provide highly nontrivial evidence for the metastability of antibranes in noncompact throat geometries since we find a consistent picture over different regimes in parameter space.

Combination Therapy With Zoledronic Acid and FES-Row Training Mitigates Bone Loss in Paralyzed Legs: Results of a Randomized Comparative Clinical Trial

Spinal cord injury (SCI) results in rapid, severe osteoporosis and an increased risk of lower extremity fractures. Despite the medical complications associated with these fractures, there is no standard of care to prevent osteoporotic fractures following SCI. Functional electrical stimulation- (FES-) assisted rowing is a promising intervention to improve bone health in SCI because of its ability to generate a muscular contraction in conjunction with mechanical loading of the lower extremity long bones. Combination therapy consisting of FES-rowing plus zoledronic acid (ZA) may be a superior treatment via inhibition of bone resorption and stimulation of new bone formation. We studied participants enrolled in a randomized clinical trial comparing FES-rowing alone with FES-rowing plus ZA to improve bone health in SCI. Volumetric CT scans at the distal femur and proximal tibial metaphyses were performed. Bone geometric properties (cortical thickness index [CTI], cortical compressive strength index [CSI], buckling ratio [BR], bending strength index) and mineral (cortical bone volume [CBV], cortical bone mineral density, cortical bone mineral content) indices were determined. In models adjusting for baseline values, we found that the CBV (p = 0.05 to 0.006), the CTI (p = 0.009), and the BR (p = 0.001) at both the distal femoral and proximal tibial metaphyses were greater in the ZA plus rowing group compared with the rowing-only group. Similarly, there was a significant positive association between the total rowing work completed and the BR at the proximal tibia (p = 0.05). A subgroup analysis of the rowing-only arm showed that gains in the CSI at the tibial metaphysis varied in a dose-dependent fashion based on the total amount of exercise performed (p = 0.009). These findings demonstrate that the osteogenic response to FES-rowing is dose-dependent. Combination therapy with ZA and FES-row training has therapeutic potential to improve bone quality, and perhaps reduce fracture risk at the most common fracture site following SCI. © 2019 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Process measure of FAST tuberculosis infection control demonstrates delay in likely effective treatment

SETTING

The tuberculous infection control strategy, FAST (Find cases Actively, Separate safely and Treat effectively), recommends prompt initiation of likely effective anti-tuberculosis treatment informed by Xpert^® MTB/RIF results.OBJECTIVE: To describe FAST implementation at Quang Nam Provincial TB and Lung Disease Hospital (QNH), Tam Ky, Viet Nam, using time to initiation of effective TB treatment as a process measure.

DESIGN

Hospital logs were used to calculate the time to likely effective treatment in patients with pulmonary TB (PTB) hospitalised during the study period.

RESULTS

Between 1 January and 31 December 2016, of 858 patients treated for PTB, 493 (57.5%) received likely effective treatment. The median time to likely effective treatment was 3 days (interquartile range 2.0-6.0), with 213 (43.2%) patients receiving likely effective treatment within 2 days. Of 81 patients receiving likely effective treatment for drug-susceptible TB with a positive Xpert result as their initial in-patient diagnostic test, 64 (79.0%) received likely effective treatment within 2 days compared with 10 (5.7%) who were initially smear-negative then found to be Xpert-positive (P < 0.0001).

CONCLUSIONS

A 'time to' process measure of the FAST tuberculous infection control strategy indicates delays in the initiation of likely effective anti-tuberculosis treatment in a resource-limited hospital. Expanding access to Xpert may speed time to likely effective treatment.