Movement variability in stroke patients and controls performing two upper limb functional tasks: a new assessment methodology

Background: In the evaluation of upper limb impairment post stroke there remains a gap between detailed kinematic analyses with expensive motion capturing systems and common clinical assessment tests. In particular, although many clinical tests evaluate the performance of functional tasks, metrics to characterise upper limb kinematics are generally not applicable to such tasks and very limited in scope. This paper reports on a novel, user-friendly methodology that allows for the assessment of both signal magnitude and timing variability in upper limb movement trajectories during functional task performance. In order to demonstrate the technique, we report on a study in which the variability in timing and signal magnitude of data collected during the performance of two functional tasks is compared between a group of subjects with stroke and a group of individually matched control subjects. Methods: We employ dynamic time warping for curve registration to quantify two aspects of movement variability: 1) variability of the timing of the accelerometer signals' characteristics and 2) variability of the signals' magnitude. Six stroke patients and six matched controls performed several trials of a unilateral ('drinking') and a bilateral ('moving a plate') functional task on two different days, approximately 1 month apart. Group differences for the two variability metrics were investigated on both days. Results: For 'drinking from a glass' significant group differences were obtained on both days for the timing variability of the acceleration signals' characteristics (p = 0.002 and p = 0.008 for test and retest, respectively); all stroke patients showed increased signal timing variability as compared to their corresponding control subject. 'Moving a plate' provided less distinct group differences. Conclusion: This initial application establishes that movement variability metrics, as determined by our methodology, appear different in stroke patients as compared to matched controls during unilateral task performance ('drinking'). Use of a user-friendly, inexpensive accelerometer makes this methodology feasible for routine clinical evaluations. We are encouraged to perform larger studies to further investigate the metrics' usefulness when quantifying levels of impairment

Diagnostic Accuracy of Adenosine Deaminase and Lymphocyte Proportion in Pleural Fluid for Tuberculous Pleurisy in Different Prevalence Scenarios

BACKGROUND: Tuberculous pleural effusion (TPE) is a paucibacillary manifestation of tuberculosis, so isolation of Mycobacterium tuberculosis is difficult, biomarkers being an alternative for diagnosis. Adenosine deaminase (ADA) is the most cost-effective pleural fluid marker and is routinely used in high prevalence settings, whereas its value is questioned in areas with low prevalence. The lymphocyte proportion (LP) is known to increase the specificity of ADA for this diagnosis. We analyse the diagnostic usefulness of ADA alone and the combination of ADA ≥ 40 U/l (ADA(40)) and LP ≥ 50% (LP(50)) in three different prevalence scenarios over 11 years in our area. MATERIALS AND METHODS: Biochemistry, cytology and microbiology studies from 472 consecutive pleural fluid samples were retrospectively analyzed. ADA and differential cell count were determined in all samples. We established three different prevalence periods, based on percentage of pleural effusion cases diagnosed as tuberculosis: 1998-2000 (31.3%), 2001-2004 (11.8%), and 2005-2008 (7.4%). ROC curves, dispersion diagrams and pre/post-test probability graphs were produced. TPE accounted for 73 episodes (mean prevalence: 15.5%). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for ADA(40) were 89%, 92.7%, 69.2% and 97.9%, respectively. For ADA(40)+LP(50) the specificity and PPV increased (98.3% and 90%) with hardly any decrease in the sensitivity or NPV (86.3% and 97.5%). No relevant differences were observed between the three study periods. CONCLUSIONS/SIGNIFICANCE: ADA remains useful for the diagnosis of TPE even in low-to-intermediate prevalence scenarios when combined with the lymphocyte proportion

Communication tools in the COVID-19 era and beyond which can optimise professional practice and patient care

Following the outbreak of the novel SARS-CoV-2 (COVID-19), the World Health Organization made a number of recommendations regarding the utilisation of healthcare services. In general, there has been a reduction in elective healthcare services including outpatient clinics, diagnostic services and elective surgery. Inevitably these reductions for all but the most urgent clinical work will have a detrimental impact on patients, and alternative ways of working including the use of telemedicine may help to mitigate this. Similarly, electronic solutions may enable clinicians to maintain inter and intra-professional working in both clinical and academic settings. Implementation of electronic solutions to minimise direct patient contact will be new to many clinicians, and the sheer number of software solutions available and varying functionality may be overwhelming to anyone unfamiliar with ‘virtual communication’. In this article, we will aim to summarise the variety of electronic communication platforms and tools available for clinicians and patients, detailing their utility, pros and cons, and some 'tips and tricks' from our experience through our work as an international research collaborative

Saddle point localization of molecular wavefunctions

The quantum mechanical description of isomerization is based on bound eigenstates of the molecular potential energy surface. For the near-minimum regions there is a textbook-based relationship between the potential and eigenenergies. Here we show how the saddle point region that connects the two minima is encoded in the eigenstates of the model quartic potential and in the energy levels of the [H, C, N] potential energy surface. We model the spacing of the eigenenergies with the energy dependent classical oscillation frequency decreasing to zero at the saddle point. The eigenstates with the smallest spacing are localized at the saddle point. The analysis of the HCN???HNC isomerization states shows that the eigenstates with small energy spacing relative to the effective (v1, v3, l) bending potentials are highly localized in the bending coordinate at the transition state. These spectroscopically detectable states represent a chemical marker of the transition state in the eigenenergy spectrum. The method developed here provides a basis for modeling characteristic patterns in the eigenenergy spectrum of bound states

Use of endobronchial one-way valves reveals questions on etiology of spontaneous pneumothorax: report of three cases

Spontaneous pneumothoraces are believed to arise when air from the supplying airway exit via a ruptured visceral pleural bleb into the pleural cavity. Endobronchial one-way valves (EBVs) allow air exit (but not entry) from individual segmental airways. Systematic deployment of EBVs was applied to three patients with secondary spontaneous pneumothoraces and persistent airleak. In all cases, balloon-catheter occlusion of the upper lobe bronchus stopped the airleak. EBVs applied to individual upper lobe segmental airways failed to terminate the airleak, which only stopped after placements of multiple EBVs to occlude all upper lobe segments. The observation questions the traditional belief of 'one-airway-one-bleb-one-leak' in spontaneous pneumothorax

Freeze-thaw treatment effects on the dynamic mechanical properties of articular cartilage

BACKGROUND: As a relatively non-regenerative tissue, articular cartilage has been targeted for cryopreservation as a method of mitigating a lack of donor tissue availability for transplant surgeries. In addition, subzero storage of articular cartilage has long been used in biomedical studies using various storage temperatures. The current investigation studies the potential for freeze-thaw to affect the mechanical properties of articular cartilage through direct comparison of various subzero storage temperatures. METHODS: Both subzero storage temperature as well as freezing rate were compared using control samples (4°C) and samples stored at either -20°C or -80°C as well as samples first snap frozen in liquid nitrogen (-196°C) prior to storage at -80°C. All samples were thawed at 37.5°C to testing temperature (22°C). Complex stiffness and hysteresis characterized load resistance and damping properties using a non-destructive, low force magnitude, dynamic indentation protocol spanning a broad loading rate range to identify the dynamic viscoelastic properties of cartilage. RESULTS: Stiffness levels remained unchanged with exposure to the various subzero temperatures. Hysteresis increased in samples snap frozen at -196°C and stored at -80°C, though remained unchanged with exposure to the other storage temperatures. CONCLUSIONS: Mechanical changes shown are likely due to ice lens creation, where frost heave effects may have caused collagen damage. That storage to -20°C and -80°C did not alter the mechanical properties of articular cartilage shows that when combined with a rapid thawing protocol to 37.5°C, the tissue may successfully be stored at subzero temperatures

Does pleural fluid appearance really matter? The relationship between fluid appearance and cytology, cell counts, and chemical laboratory measurements in pleural effusions of patients with cancer

<p>Abstract</p> <p>Background</p> <p>Previous reports have suggested that the appearance of pleural effusions (i.e., the presence or absence of blood) might help to establish the etiology of the effusions. This study explores the relationship between pleural fluid appearance and the results of chemical and cytological analyses in a group of patients with recurrent symptomatic pleural effusions and a diagnosis of cancer.</p> <p>Methods</p> <p>Medical records were reviewed from all 390 patients who were diagnosed with cancer, who underwent thoracentesis before placement of an intrapleural catheter (IPC) between April 2000 and January 2006. Adequate information for data analysis was available in 365 patients. The appearance of their pleural fluid was obtained from procedure notes dictated by the pulmonologists who had performed the thoracenteses. The patients were separated into 2 groups based on fluid appearance: non-bloody and bloody. Group differences in cytology interpretation were compared by using the chi square test. Cellular counts, chemical laboratory results, and survival after index procedure were compared by using the student's t test.</p> <p>Results</p> <p>Pleural fluid cytology was positive on 82.5% of the non-bloody effusions and on 82.4% of the bloody ones. The number of red blood cells (220.5 × 10³/μL vs. 12.3 × 10³/μL) and LDH values (1914 IU/dl vs. 863 IU/dl) were statistically higher in bloody pleural effusions.</p> <p>Conclusion</p> <p>The presence or absence of blood in pleural effusions cannot predict their etiology in patients with cancer and recurrent symptomatic pleural effusions.</p

Genotyping of Human Lice Suggests Multiple Emergences of Body Lice from Local Head Louse Populations

While being phenotypically and physiologically different, human head and body lice are indistinguishable based on mitochondrial and nuclear genes. As protein-coding genes are too conserved to provide significant genetic diversity, we performed strain-typing of a large collection of human head and body lice using variable intergenic spacer sequences. Ninety-seven human lice were classified into ninety-six genotypes based on four intergenic spacer sequences. Genotypic and phylogenetic analyses using these sequences suggested that human head and body lice are still indistinguishable. We hypothesized that the phenotypic and physiological differences between human head and body lice are controlled by very limited mutations. Under conditions of poor hygiene, head lice can propagate very quickly. Some of them will colonize clothing, producing a body louse variant (genetic or phenetic), which can lead to an epidemic. Lice collected in Rwanda and Burundi, where outbreaks of louse-borne diseases have been recently reported, are grouped tightly into a cluster and those collected from homeless people in France were also grouped into a cluster with lice collected in French non-homeless people. Our strain-typing approach based on highly variable intergenic spacers may be helpful to elucidate louse evolution and to survey louse-borne diseases

Assessment of normal tricuspid valve anatomy in adults by real-time three-dimensional echocardiography

Background: The tricuspid valve (TV) is a complex structure. Unlike the aortic and mitral valve it is not possible to visualize all TV leaflets simultaneously in one cross-sectional view by standard two-dimensional echocardiography (2DE) either transthoracic or transesophageal due to the position of TV in the far field. Aim: Quantitative and qualitative assessment of the normal TV using real-time 3-dimensional echocardiography (RT3DE). Methods: RT3DE was performed for 100 normal adults (mean age 30 ± 9 years, 65% males). RT3DE visualization was evaluated by 4-point score (1: not visualized, 2: inadequate, 3: sufficient, and 4: excellent). Measurements included TV annulus diameters (TAD), TV area (TVA), and commissural width. Results: In 90% of patients with good 2DE image quality, it was possible to analyse TV anatomy by RT3DE. A detailed anatomical structure including unique description and measurement of tricuspid annulus shape and size, TV leaflets shape, and mobility, and TV commissural width were obtained in majority of patients. Identification of each TV leaflet as seen in the routine 2DE views was obtained. Conclusion: RT3DE of the TVis feasible in a large number of patients. RT3DE may add to functional 2DE data in description of TV anatomy and providing highly reproducible and actual reality (anatomical and functional) measurements