Multidisciplinary analysis of cancer-related fatigue at the time of diagnosis: preliminary results of the BIOCARE FActory cohort

PURPOSE

Cancer-related fatigue (CRF) is a common side effect of cancer and cancer treatment that significantly impairs the quality of life and can persist for years after treatment completion. Although fatigue is often associated with cancer treatment, it is also a result of the disease itself, even before intervention. CRF at the time of diagnosis may affect treatment timing or completion and is a consistent predictor of post-treatment fatigue at any time. The mechanisms underlying CRF are multidimensional and not well understood, particularly at the time of diagnosis.

METHODS

Sixty-five breast cancer patients at the time of diagnosis were included. The participants completed self-assessment questionnaires about CRF, sleep disturbances, and emotional symptoms and wore an accelerometer to assess levels of spontaneous physical activity and sleep quality. During the experimental session, the participants underwent cognitive, neuromuscular, and exercise metabolism evaluations.

RESULTS

Using augmented backward elimination regression, this study found that emotional symptoms and perceived sleep disturbances were the strongest predictors of CRF (adjusted r2 = 0.51). Neuromuscular fatigability and sleep disturbance were also associated with physical dimensions, whereas cognitive performance was associated with cognitive dimensions.

CONCLUSION

At the time of diagnosis, emotional and cognitive dimensions are over-represented compared to the general population, and specific subdimensions have specific predictors that support the idea of distinct mechanisms. Evaluating CRF subdimensions and their potential mechanisms at the time of diagnosis would be particularly relevant for identifying high-risk patients and offering them appropriate interventions.

TRIAL REGISTRATION

This study was registered at ClinicalTrials.gov (NCT04391543) in May, 2020.

Comparison of neuromuscular fatigability amplitude and etiologies between fatigued and non-fatigued cancer patients

PURPOSE

Cancer-related fatigue (CRF) is the most reported side effect of cancer and its treatments. Mechanisms of CRF are multidimensional, including neuromuscular alterations leading to decreased muscle strength and endurance (i.e., fatigability). Recently, exercise fatigability and CRF have been related, while fatigability mechanisms remain unclear. Traditionally, fatigability is assessed from maximal voluntary contractions (MVC) decrease, but some authors hypothesized that the rate of force development (RFD) determined during a rapid contraction could also be an interesting indicator of functional alterations. However, to our knowledge, no study investigated RFD in cancer patients. The purpose of this study was to determine whether RFD, fatigability amplitude, and etiology are different between fatigued and non-fatigued cancer patients.

METHODS

Eighteen participants with cancer, divided in fatigued or non-fatigued groups according their CRF level, completed a 5-min all-out exercise in ankle plantar flexor muscles composed of 62 isometric MVC of 4 s with 1 s rest, to assess fatigability amplitude as the force-time relationship asymptote (FA). Before and after exercise, fatigability etiologies (i.e., voluntary activation (VA) and evoked forces by electrical stimulation (Db100)) were assessed as well as RFD in 50 and 100 ms (RFD50 and RFD100, respectively) during rapid contractions.

RESULTS

FA is significantly lower in fatigued group. Significant differences were found between pre- and post-exercise VA, Db100, RFD50, and RFD100 for both groups, with no statistical difference between groups.

CONCLUSION

During treatments, fatigability is higher in fatigued patients; however, the mechanisms of fatigability and RFD alterations are similar in both groups.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04391543, May 2020.

Simulation of laser-induced ionization in wide bandgap solid dielectrics with a particle-in-cell code

Modeling the laser-plasma interaction within solids is crucial in controlling ultrafast laser processing of dielectrics, where the pulse propagation and plasma formation dynamics are highly intricate. This is especially important when dealing with nano-scale plasmas where specific phenomena of plasma physics, such as resonance absorption, can significantly impact the energy deposition process. In this article, we report on adapting of a Particle-In-Cell code, EPOCH, to model the laser-plasma interaction within solids. This is performed by implementing a background permittivity and by developing and validating adapted field ionization and impact ionization modules. They are based on the Keldysh ionization theory and enable the modeling of ionization processes within solids. The implementation of these modules was validated through comparisons with a hydrodynamic code and existing literature. We investigate the necessary number of super-particles per cell to model realistic ionization dynamics. Finally, we apply the code to explore the dynamics of plasma formation in the regime of of quantized structuring of transparent films. Our study elucidates how a stack of nano-plasma layers can be formed by the interference of a pulse with its reflection on the exit surface of a high refractive index material.

Mathematical modeling of exercise fatigability in the severe domain: A unifying integrative framework in isokinetic condition

Muscle fatigue is the decay in the ability of muscles to generate force, and results from neural and metabolic perturbations. This article presents an integrative mathematical model that describes the decrease in maximal force capacity (i.e. fatigue) over exercises performed at intensities above the critical force Fc (i.e. severe domain). The model unifies the previous Critical Power Model and All-Out Model and can be applied to any exercise described by a changing force F over time. The assumptions of the model are (i) isokinetic conditions, an intensity domain of Fc Collapse

Key Words

• All-out
• Anaerobic capacities
• Critical power
• Endurance
• Exercise fatigability
• Fatigue
• Maximal force capacity
• Muscular capacities
• Power-time relationship
• Time to exhaustion

Collapse

MESH Headings

• Exercise/physiology
• Muscle Fatigue
• Muscles/physiology
• Models, Theoretical
• Muscle, Skeletal/physiology

Collapse

Grants Collapse

Building a biopsychosocial model of cancer-related fatigue: the BIOCARE FActory cohort study protocol

Background

Cancer-related fatigue (CRF) is the most common side effect of cancer and cancer treatment. CRF prevalence is up to 50% in breast cancer patients and can continue several years after cancer remission. This persistent subjective sense of exhaustion is multifactorial. Numerous parameters have been evidenced to be related to CRF across biological, physical, psychological, social and/or behavioral dimensions. Although CRF has been studied for many years, the majority of previous studies focused on only one dimension, i.e., physical function. Moreover, few studies investigated CRF longitudinally with repeated measures. These are the two main obstacles that limit the understanding of CRF mechanisms. The purpose of this study is to create a biopsychosocial model of CRF with simultaneous and longitudinal anthropometric, clinical, biological, physical, psychological and sociological parameters.

Methods

BIOCARE FActory is a multicentric prospective study that will consist of an 18-month follow-up of 200 women diagnosed with breast cancer. Four visits will be scheduled at diagnosis, after treatments, and 12 and 18 months after diagnosis. The same procedure will be followed for each visit. Each session will be composed of anthropometric data collection, a semi-structured interview, cognitive tests, postural control tests, neuromuscular fatigability tests and a cardiorespiratory fitness test. Clinical and biological data will be collected during medical follow-ups. Participants will also complete questionnaires to assess psychological aspects and quality of life and wear an actigraphy device. Using a structural equation modeling analysis (SEM), collected data will build a biopsychosocial model of CRF, including the physiological, biological, psychological, behavioral and social dimensions of CRF.

Discussion

This study aims to highlight the dynamics of CRF and its correlates from diagnosis to post treatment. SEM analysis could examine some relations between potential mechanisms and CRF. Thus, the biopsychosocial model will contribute to a better understanding of CRF and its underlying mechanisms from diagnosis to the aftermaths of cancer and its treatments.

Trial registration

This study is registered at ClinicalTrials.gov (NCT04391543), May 2020.

A solver based on pseudo-spectral analytical time-domain method for the two-fluid plasma model

A number of physical processes in laser-plasma interaction can be described with the two-fluid plasma model. We report on a solver for the three-dimensional two-fluid plasma model equations. This solver is particularly suited for simulating the interaction between short laser pulses with plasmas. The fluid solver relies on two-step Lax-Wendroff split with a fourth-order Runge-Kutta scheme, and we use the Pseudo-Spectral Analytical Time-Domain (PSATD) method to solve Maxwell's curl equations. Overall, this method is only based on finite difference schemes and fast Fourier transforms and does not require any grid staggering. The Pseudo-Spectral Analytical Time-Domain method removes the numerical dispersion for transverse electromagnetic wave propagation in the absence of current that is conventionally observed for other Maxwell solvers. The full algorithm is validated by conservation of energy and momentum when an electromagnetic pulse is launched onto a plasma ramp and by quantitative agreement with wave conversion of p-polarized electromagnetic wave onto a plasma ramp.

Added value of MRI for the diagnosis of adnexal torsion in children and adolescents after inconclusive ultrasound examination

PURPOSE

The purpose of this study was to assess the performance of magnetic resonance imaging (MRI) in children and adolescents with suspected adnexal torsion (AT) after inconclusive initial ultrasound examination.

MATERIALS AND METHODS

Twenty-eight girls with a mean age of 12±4 (SD) years (range: 1 month to 18years) were included. All had clinically suspected AT and inconclusive initial ultrasound findings followed by pelvic MRI as a second-line imaging modality. The final diagnosis was obtained by surgery or follow-up. Two radiologists blinded to the clinical, ultrasound and surgical data, retrospectively and independently reviewed MRI examinations. Clinical and MRI features associated with AT were searched for using univariate analyses.

RESULT

Among the 28 patients, 10/28 patients (36%) had AT and 22/28 (79%) had an ovarian or tubal mass. AT was associated with an age<13years (OR: 10.7; 95% CI: 1.3-148.2) (P=0.022) and a whirlpool sign at MRI (OR: 61.0; median unbiased estimate, 7.2) (P<0.0001). When a mass was present, the best quantitative MRI criteria for AT were mass volume and ovary-corrected volume≥30cm³ (κ=0.72 and 0.61, respectively), mass axis length≥5cm (κ=0.90), and mass surface area≥14 cm² (κ=0.58), with moderate to almost perfect interobserver agreement. The overall sensitivity, specificity and accuracy of MRI for the diagnosis of AT were 100% (10/10; 95% CI: 69-100), 94% (17/18; 95% CI: 73-100) and 96% (27/28; 95% CI: 82-100) respectively, with perfect interobserver agreement (κ=1).

CONCLUSION

In pediatric patients with suspected AT and inconclusive initial ultrasound examination, a strategy including MRI as a second-line imaging modality should be considered if MRI does not delay a potential surgery.

Synthesis of Densely Functionalized Pyrimidouracils by Nickel(II)-Catalyzed Isocyanide Insertion

A robust nickel-catalyzed oxidative isocyanide insertion/C–H amination by reaction of readily available N-uracil-amidines with isocyanides affording polysubstituted pyrimidouracils has been reported. The reaction proceeds in moderate to quantitative yield, under mild conditions (i.e., green solvent, air atmosphere, moderate temperature). The broad range of structurally diverse isocyanides and N-uracil-amidines that are tolerated make this method an interesting alternative to the currently available procedures toward pyrimidouracils.

Efficacy, Tolerability, and Safety of Low-Volume Bowel Preparations for Patients with Inflammatory Bowel Diseases: The French Multicentre CLEAN Study

BACKGROUND

Standard high-volume polyethylene glycol [PEG] bowel preparations [PEG-4L] are recommended for patients with inflammatory bowel disease [IBD] undergoing colonoscopy. However, low-volume preparations [≤2 L of active volume] are often used in clinical practice. The aim of this study was to evaluate the efficacy, tolerability, and safety of the various bowel preparations for patients with IBD, including low-volume preparations.

METHODS

We conducted a French prospective multicentre observational study over a period of 1 month. Patients aged 18-75 years with IBD with an indication of colonoscopy independent of the study were enrolled. The choice of the preparation was left to the investigators, as per their usual protocol. The patients' characteristics, disease, and colonoscopy characteristics were recorded, and they were given self-reported questionnaires.

RESULTS

Twenty-five public and private hospitals enrolled 278 patients. Among them, 46 had a disease flare and 41 had bowel stenoses. Bowel preparations for colonoscopy were as follows: 42% received PEG-2L, 29% received sodium picosulfate [Pico], 15% received PEG-4L, and 14% had other preparations. The preparation did not reach the Boston's score efficacy outcome in the PEG-4L group in 51.2% of the patients [p = 0.0011]. The preparation intake was complete for 59.5% in the PEG-4L group, compared with 82.9% in the PEG-2L group and 93.8% in the Pico group [p < 0.0001]. Tolerability, as assessed by the patients' VAS, was significantly better for both Pico and PEG-2L compared with PEG-4L, and better for Pico compared with PEG-2L [p = 0.008; p = 0.0003]. In multivariate analyses, low-volume preparations were independent factors of efficacy and tolerability. Adverse events occurred in 4.3% of the patients.

CONCLUSIONS

Preparations with PEG-2L and Pico were equally safe, with better efficacy and tolerability outcomes compared with PEG-4L preparations. The best efficacy/tolerance/safety profile was achieved with the Pico preparation.

Catalytic Aerobic Oxidation of C(sp3 )-H Bonds

Oxidation reactions are a key technology to transform hydrocarbons from petroleum feedstock into chemicals of a higher oxidation state, allowing further chemical transformations. These bulk-scale oxidation processes usually employ molecular oxygen as the terminal oxidant as at this scale it is typically the only economically viable oxidant. The produced commodity chemicals possess limited functionality and usually show a high degree of symmetry thereby avoiding selectivity issues. In sharp contrast, in the production of fine chemicals preference is still given to classical oxidants. Considering the strive for greener production processes, the use of O₂ , the most abundant and greenest oxidant, is a logical choice. Given the rich functionality and complexity of fine chemicals, achieving regio/chemoselectivity is a major challenge. This review presents an overview of the most important catalytic systems recently described for aerobic oxidation, and the current insight in their reaction mechanism.

In-utero aspiration vs expectant management of anechoic fetal ovarian cysts: open randomized controlled trial

OBJECTIVE

To assess the efficacy and safety of in-utero aspiration (IUA) of anechoic fetal ovarian cysts.

METHODS

This multicenter, prospective, randomized open trial in two parallel groups included women from nine outpatient fetal medicine departments with singleton pregnancy ≥ 28 weeks of gestation and a female fetus with an ultrasound-diagnosed simple ovarian cyst, defined as a single fully anechoic cystic structure measuring ≥ 30 mm. They were allocated randomly to IUA under ultrasound guidance or expectant management. All procedures were performed by trained senior obstetricians. Primary outcome was need for neonatal intervention, by laparoscopy, laparotomy or transabdominal aspiration. Secondary outcomes were in-utero involution of the cyst and oophorectomy at birth. Analyses were conducted according to the intention-to-treat principle.

RESULTS

Of 61 participants, 34 were allocated to IUA and 27 to expectant management. Three IUA procedures (9%) could not be performed (one due to fetal position and two due to aspirations being dry). The remaining 31 IUA procedures were uneventful. The incidence of neonatal intervention did not differ significantly between the IUA and the expectant management groups (20.6% vs 37.0%; relative risk (RR), 0.55; 95% CI, 0.24-1.27). Nonetheless, IUA was associated with increased incidence of in-utero involution of the cyst (47.1% vs 18.5%; RR, 2.54; 95% CI, 1.07-6.05) and reduced rate of oophorectomy (3.0% vs 22.0%; RR, 0.13; 95% CI, 0.02-1.03) compared with expectant management.

CONCLUSION

IUA of anechoic fetal ovarian cysts, compared with expectant management, was not associated with a reduction in overall neonatal interventions but was associated with a reduced oophorectomy rate. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

The position of a written document in preoperative information for pediatric surgery: A randomized controlled trial on parental anxiety, knowledge, and satisfaction

INTRODUCTION

Preoperative information is a legal and ethical obligation. Very little studies have evaluated the preoperative information method in pediatrics. Having a child operated on is stressful for the parents. Improving information is a way to lower their anxiety. Our study aims to measure the impact of a leaflet, which supports spoken information on parental anxiety, the comprehension-memorization of the information and their satisfaction.

MATERIALS & METHODS

Prospective study including 178 patients of outpatient surgery, randomized in two groups: spoken information versus spoken information supported by a leaflet, which is then handed out to the parents. The messages were identical: physiopathology, risks without treatment, surgical technique and its possible complications, description of the hospitalization day, and postoperative care. Parental evaluation was made with self-questionnaires after the preoperative consultation, then on the day of surgery. At each moment we evaluated the level of anxiety, satisfaction of information quality and the comprehension-memorization of the data.

RESULTS

Written information significantly improves the scores of comprehension-memorization, parental satisfaction and significantly decreases the level of anxiety.

CONCLUSION

Significant impact of the written document as communication support in pediatric surgery, validating the method and encouraging it to be generalized to other pediatric surgery acts.

LEVEL OF EVIDENCE

Level I.

TYPE OF STUDY

Prognosis study.

Clinical and haemodynamic risk factors associated with discrepancies in lower limb length with capillary malformations: data from the national paediatric French cohort CONAPE

BACKGROUND

Genetics discoveries have allowed for a better understanding of capillary malformations (CMs) associated with overgrowth syndrome. However, molecular analyses are still not easy to perform or interpret. Other analytical methods are needed.

OBJECTIVES

To identify clinical and haemodynamic factors associated with leg length discrepancy (LLD) in children with CMs of the lower limbs.

METHODS

Data were obtained from the multicentre French national cohort CONAPE (COhorte Nationale d'enfants atteints d'Angiome Plan de membrE inférieur), from children aged 2-12 years old with CMs of the lower limbs. Clinical characteristics were prospectively collected. Haemodynamic factors were measured by an sonographer who calculated the arterial blood flow (ABF) in both lower limbs. An ABF difference ≥ 50% between the two lower limbs was considered relevant. LLD ≥ 2% was determined by the same radiologist on centralized radiographs.

RESULTS

We analysed data at baseline for 96 children. The mean ± SD age was 5·6 ± 3·1 years; 49 (51%) were male; and 14 (15%) showed LLD. In total, 32 patients (33%) had venous anomalies, 13 (14%) lymphatic anomalies and in one child a diagnosis of Parkes Weber syndrome was made. Only an increased circumference above the knee was more frequent with than without LLD (43% vs. 13%, P = 0·02). In all, 10/79 patients (13%) showed a difference in ABF ≥ 50%: four had LLD. The frequency of differences in ABF ≥ 50% was greater with than without LLD [33% (n = 4/12) vs. 9% (n = 6/67), P = 0·04].

CONCLUSIONS

ABF measured by Duplex ultrasonography is a simple, low-cost and noninvasive complementary examination for help in detecting LLD, with a difference of ≥ 50% possibly associated.

[Impact of a written document for preoperative information on the use of Internet by parents]

INTRODUCTION

Preoperative information is a legal and ethical obligation. Very few studies have evaluated the preoperative information method in pediatrics. Having a child operated on is stressful for parents. The use of Internet to look for data on the pathology and its treatment is frequent, but often unprofitable and sometimes even harmful. This study aimed to measure the impact of a leaflet, which supports spoken information in preoperative consultation, on parents' use of the Internet before surgery.

MATERIAL AND METHODS

Prospective study including 178 patients of outpatient surgery, randomized into two groups: spoken information alone versus spoken information supported by a personalized leaflet, which is then handed out to the parents. The messages were identical: physiopathology, risks without treatment, surgical technique, possible complications, description of the hospitalization day, and postoperative care. Parental evaluation was carried out with self-administered questionnaires after the preoperative consultation, then on the day of surgery. At each moment the rate of Internet use, its reasons, and the benefits were evaluated.

RESULTS

The written document significantly reduced the use of the Internet by parents regardless of the child's age, their degree of anxiety, their level of understanding, and the time between consultation and the intervention.

CONCLUSION

This study confirms the significant impact of the leaflet as a communication tool in pediatric surgery and the substantial utility for parents. This encourages us to generalize this method to other pediatric surgery acts.

High pressure balloon dilatation of the ureterovesical junction in primary obstructive megaureter: Infectious morbidity

INTRODUCTION

The objective of this study is to investigate the infectious morbidity associated with high-pressure balloon dilatation (HPBD) and an indwelling double J stent, in primary obstructive megaureter.

METHODS

We reviewed the cases of 12 patients undergoing endoscopic treatment for primary obstructive megaureter from January 2012 to January 2015. The characteristics of the infection and data concerning the patient and the intervention were analyzed.

RESULTS

The frequency of preoperative urinary tract infection (UTI) was 58%. The procedure was feasible in 100% of cases. Two patients required a second dilatation. One patient underwent Cohen's ureteral reimplantation after failure of the second dilatation. The frequency of postoperative UTI was 25%. All these infections occurred in patients with a double J stent. None of the patients had UTI after stent removal. None of the patients developed postoperative vesicoureteral reflux (VUR) after HPBD.

CONCLUSION

Endoscopic balloon dilatation has been shown to have good short- mid- and long-term outcomes. In our experience, the morbidity of this procedure mostly results from infections, exclusively related to the use of a double J stent. The placement of a double J stent has a significant medical and economic impact. A definitive decision about the utility of double J stents will require studies of further dilatation without the placement of a double J stent.

LEVEL OF EVIDENCE

4.

[Fetal MRI practices in a university prenatal center]

OBJECTIVES

Fetal MRI is a third intention examination to prenatal diagnosis. If its diagnostic value is well known in many pathologies, its place in the management of pregnancies remains unclear.

METHODS

We collected retrospectively demographical, radiological (fetal MRI indications, fetal anatomical region and diagnostic information provided by fetal MRI) and obstetrical data of pregnant patients in university prenatal center during a 5 years' period.

RESULTS

Among 2439 patients of the prenatal center, 196 (8%) patients with fetal MRI were included. The main anatomical regions studied were the brain (n=132, 67%), the thorax (n=31, 16%) and the abdomen (n=25, 13%). No cardiac fetal MRI was performed. Ninety-five percent of fetal MRI was consecutively of an ultrasound sign. Fetal brain MRI was abnormal in 65% of cases, the thoracic and abdominopelvic MRI in 81.5%. The ultrasound diagnosis was unchanged in 42%, completed in 50% and redirected in 8% of cases. A termination of pregnancy was deemed admissible in 31% of patients with MRI versus 21% in patients without MRI (P=0.001).

CONCLUSION

Fetal MRI requires selective indications and provides additional diagnostic information with important implications for the future of the pregnancy, particularly in case of severe and incurable pathologies. Our results could be useful as a reference basis for the comparison with others prenatal center practices.

Concise Xanthine Synthesis through a Double-Amidination Reaction of a 6-Chlorouracil with Amidines using Base-Metal Catalysis

A new and concise route towards xanthines through a double-amidination reaction is described; consecutive intermolecular C-Cl and intramolecular oxidative C-H amidination. N-uracil amidines are obtained through S_N AE on a 6-chlorouracil with amidines. Direct Cu-catalyzed oxidative C-H amidination on these N-uracil amidines yields polysubstituted xanthines. Sustainable oxidants, tBu₂ O₂ or O₂ , can be used in this oxidase-type reaction. The protocol allows for the introduction of N1, N3, N7, and C8 substituents during the xanthine-scaffold construction, thus avoiding post-functionalization steps. Both 6-chlorouracils and amidines are readily available commercially or through synthesis.

A single enhanced phase is sufficient for the initial computed tomography evaluation of retroperitoneal tumors in children

PURPOSE

The goal of this study was to evaluate the incremental value of unenhanced phase in the initial evaluation of retroperitoneal tumors in children by comparison with an enhanced phase alone using computed tomography (CT).

MATERIALS AND METHODS

A total of 53 patients (26 girls, 27 boys) with a total of 53 tumors who had CT examination of the abdomen and pelvis for the initial assessment of retroperitoneal tumor were retrospectively included. All CT examinations were obtained with an unenhanced set of CT images and a set of CT images obtained after intravenous administration of iodinated contrast material. One junior and one senior radiologist independently evaluated the two sets in two separate reading sessions. CT images were analyzed for tumor calcifications, tumor location, vascular encasement, local invasion and tumor content.

RESULTS

Calcifications were present in 24/53 tumors (45%). On the enhanced set, the senior radiologist was able to detect calcifications in 22/24 tumors (92%) and the junior radiologist in 20/24 tumors (83%), yielding sensitivities of 92% and 83%, and specificities of 96.5% and 100%, respectively. Inter-observer agreement was excellent (Kappa=0.89). Tumor location was correctly determined by the senior radiologist in 53/53 tumors (100%) and 37/53 tumors (70%) by the junior radiologist. Using the unenhanced set, the senior radiologist was able to assess vascular encasement in 26/53 tumors (49%) against 21/53 (39%) for the junior radiologist. For tumor content, agreement between the enhanced and combined unenhanced and enhanced CT was 77% for both radiologists.

CONCLUSION

Enhanced CT performs as well as unenhanced CT for evidencing calcifications and is therefore sufficient for the initial assessment of retroperitoneal tumor in children.

The neuromuscular fatigue induced by repeated scrums generates instability that can be limited by appropriate recovery

The aim of this study was to evaluate the influence of the fatigue on the machine scrum pushing sagittal forces during repeated scrums and to determine the origin of the knee extensor fatigue. Twelve elite U23 rugby union front row players performed six 6-s scrums every 30 s against a dynamic scrum machine with passive or active recovery. The peak, average, and the standard deviation of the force were measured. A neuromuscular testing procedure of the knee extensors was carried out before and immediately after the repeated scrum protocol including maximal voluntary force, evoked force, and voluntary activation. The average and peak forces did not decrease after six scrums with passive recovery. The standard deviation of the force increased by 70.2 ± 42.7% (P < 0.001). Maximal voluntary/evoked force and voluntary activation decreased (respectively 25.1 ± 7.0%, 14.6 ± 5.5%, and 24 ± 9.9%; P < 0.001). The standard deviation of the force did not increase with active recovery and was associated with lower decrease of maximal voluntary/evoked force and voluntary activation (respectively 12.8 ± 7.9%, 4.9 ± 6.5%, and 7.6 ± 4.1%; all P < 0.01). As a conclusion repeated scrummaging induced an increased machine scrum pushing instability associated with central and peripheral fatigue of the knee extensors. Active recovery seems to limit all these manifestations of fatigue.

Neodymium uranyl peroxide synthesis by ion exchange on ammonium uranyl peroxide nanoclusters

This study demonstrates the ability of ammonium uranyl peroxide nanoclusters U32R-NH₄ to undergo exchange in between NH₄⁺ and trivalent (Nd³⁺) or tetravalent (Th⁴⁺) cations in the solid state.

The learning process of the hydrolocalization technique performed during ultrasound-guided regional anesthesia

BACKGROUND

Because poor echogenicity of the needle remains a safety issue, we decided to analyze the learning process of the hydrolocalization technique (Hloc) performed to continuously identify needle-tip anatomical position during many ultrasound-guided regional anesthesia procedures.

METHODS

Ten senior anesthesiologists naïve to the Hloc agreed to participate in the study. They were requested to perform 40 out-of-plane (OOP) approach ultrasound-guided axillary blocks (AB) each using the Hloc. The Hloc, which is a needle-tip localization principle, was performed by means of repetitive injections of a small amount of a local anesthetic solution (0.5-1 ml) under an ultrasound beam. Details of the learning process and skill acquisition of the Hloc were derived from the following parameters: the duration of block placement, a measure of the perceived difficulty of needle-tip visualization, a measure of block placement difficulty, and the amount of local anesthetics solution required for the technique.

RESULTS

Four hundred ABs were performed. The success rate of an ultrasound-guided AB was 98%. The Hloc was successful in all patients. Skill acquisition over time of the Hloc was associated with a significant reduction of both the duration and the perceived difficulty of ABs placement. Apprenticeship data revealed that 20 blocks were required to successfully place AB within 5 min in most cases using the Hloc.

CONCLUSION

The Hloc performed during the OOP approach of ultrasound-guided regional anesthesia is a simple technique with a relatively short learning process feasible for efficient placement of ABs.