Validation of the use of dried blood spots in a chikungunya virus IgG serological assay

Dried blood spot (DBS) sampling is a simple, fast, and minimally invasive blood collection method that is particularly useful for diagnostic or epidemiological studies in hard-to-reach populations. Nevertheless, the use of DBS in assays that have been optimized with gold-standard samples (serum or plasma) must be optimized to yield reliable results. Here, we describe the validation of DBS in a commercial assay to measure IgG against chikungunya virus (CHIKV IgG ELISA; Euroimmun, Lübeck, Germany). During a health survey of people experiencing homelessness in Salvador, Brazil, between September 2021 and February 2022, a subset (75/523; 14.3%) of the study participants had paired capillary (for DBS preparation) and venous (for serum separation) blood samples collected. A pilot optimization test was initially performed with 17 paired samples to compare the CHIKV IgG ELISA absorbance values between serum and three different dilutions of DBS. Based on the preliminary results, the best DBS dilution was selected for a final evaluation comparing paired serum and DBS samples from 58 participants. The sensitivity and specificity of the CHIKV ELISA of DBS compared to sera were 100% (95% C.I.: 85.8-100%) and 100% (95% C.I.: 93-100%), respectively. In the linear regression analysis, a coefficient of determination (R2) value of 0.98 indicated the excellent performance of DBS in predicting the serum levels of IgG CHIKV antibodies. Our findings suggest that DBS at an optimized dilution is reliable for investigating the prevalence of CHIKV IgG antibodies during population surveys in the commercial assay tested here.

Order-chaos transition in correlation diagrams and quantization of period orbits

Eigenlevel correlation diagrams has proven to be a very useful tool to understand eigenstate characteristics of classically chaotic systems. In particular, we showed in a previous publication [Phys. Rev. Lett. 80, 944 (1998)0031-900710.1103/PhysRevLett.80.944] how to unveil the scarring mechanism, a cornerstone in the theory of quantum chaos, using the Planck constant as the correlation parameter. By increasing the Planck constant, we induced a transition from order to chaos, in which scarred wave functions appeared as the interaction of pairs of eigenstates in broad avoided crossings, forming a well-defined frontier in the correlation diagram. In this paper, we demonstrate that this frontier can be obtained by means of the semiclassical quantization of the involved scarring periodic orbits. Additionally, in order to calculate the Maslov index of each scarring periodic orbit, which is necessary for the semiclassical quantization procedure, we introduce a straightforward method based on Lagrangian descriptors. We illustrate the theory using the vibrational eigenstates of the LiCN molecular system.

Geometrodynamic approach to conjugate points and the Maslov index

Maslov indices are an essential ingredient in the semiclassical approaches to quantum mechanics, as they are also related to the conjugate points of the corresponding trajectory, which reflects the dynamics in its neighborhood. In this paper, we show how these important topological parameters can be computed using the geometrodynamic approach to dynamics. Illustrations in two- and three-dimensional systems are presented and discussed.

Salt marsh fragmentation in a mesotidal estuary: Implications for medium to long-term management

During the last decades many salt marshes worldwide have suffered important losses in their extent and associated ecosystem services. The salt marshes of San Vicente de la Barquera estuary (N Spain) are a clear example of this, with a drastic reduction in vegetation surface over the last 60 years. This paper provides insights into the main factors controlling salt marsh functioning in sheltered estuarine areas. Regional and local factors have been disaggregated to identify the main drivers controlling the functioning of the salt marsh to develop appropriate management measures according to the evolution of the system. These factors have been studied in their spatial context through detailed maps of change in vegetation cover combined with topographic data obtained from UAV and RTK-DGPS surveys. The results demonstrate that in this estuary the salt marsh area is declining following a fragmentation process. No clear pattern of vegetation loss/gain with elevation has been identified. However, the results point to increased hydrodynamic stress in the area, with stronger currents inside the estuary. This is probably the major factor responsible for the decline of the salt marshes in the San Vicente de la Barquera estuary. Furthermore, several human interventions during the 20th century (local drivers) have also probably contributed to a lower resilience against SLR (regional driver). This work demonstrates that both natural and human drivers of change need to be considered when characterizing the evolution of salt marshes, wherever efficient management strategies need to be designed.

Lagrangian descriptors for the Bunimovich stadium billiard

We apply the concept of Lagrangian descriptors to the dynamics on the Bunimovich stadium billiard, a two-dimensional ergodic system with singular families of trajectories, namely, the bouncing ball and the whispering gallery orbits. They play a central role in structuring the phase space, which is unveiled here by means of the Lagrangian descriptors applied to the associated map on the boundary. More interestingly, we also consider the open stadium, which in the optical case (Fresnel's laws) can be directly related to recent microlaser experiments. We find that the structure of the emission profile of these systems can be easily described thanks to the open version of the Lagrangian descriptors.

Bohr-Sommerfeld-like quantization in the theory of walking droplets

Recent experiments have shown that self-propelled millimetric walking droplets bouncing on a vibrating liquid surface exhibit phenomena, such as interference or tunneling, that so far were thought to be possible only in the microscopic realm. Here we present calculations showing that the surface wave satisfies, in the long-memory limit, a Bohr-Sommerfeld quantization-like relation. This strongly suggest the possibility of a novel fundamental type of quantization in these experiments, which can simultaneously explain their emulation of the quantum behavior and, more importantly, shed light into some of the interpretational difficulties of the standard quantum theory.

Elective, Non-urgent Procedures and Aesthetic Surgery in the Wake of SARS-COVID-19: Considerations Regarding Safety, Feasibility and Impact on Clinical Management

BACKGROUND

The worldwide spread of a novel coronavirus disease (COVID-19) has led to a near total stop of non-urgent, elective surgeries across all specialties in most affected countries. In the field of aesthetic surgery, the self-imposed moratorium for all aesthetic surgery procedures recommended by most international scientific societies has been adopted by many surgeons worldwide and resulted in a huge socioeconomic impact for most private practices and clinics. An important question still unanswered in most countries is when and how should elective/aesthetic procedures be scheduled again and what kind of organizational changes are necessary to protect patients and healthcare workers when clinics and practices reopen. Defining manageable, evidence-based protocols for testing, surgical/procedural risk mitigation and clinical flow management/contamination management will be paramount for the safety of non-urgent surgical procedures.

METHODS

We conducted a MEDLINE/PubMed research for all available publications on COVID-19 and surgery and COVID-19 and anesthesia. Articles and referenced literature describing possible procedural impact factors leading to exacerbation of the clinical evolution of COVID-19-positive patients were identified to perform risk stratification for elective surgery. Based on these impact factors, considerations for patient selection, choice of procedural complexity, duration of procedure, type of anesthesia, etc., are discussed in this article and translated into algorithms for surgical/anesthesia risk management and clinical management. Current recommendations and published protocols on contamination control, avoidance of cross-contamination and procedural patient flow are reviewed. A COVID-19 testing guideline protocol for patients planning to undergo elective aesthetic surgery is presented and recommendations are made regarding adaptation of current patient information/informed consent forms and patient health questionnaires.

CONCLUSION

The COVID-19 crisis has led to unprecedented challenges in the acute management of the crisis, and the wave only recently seems to flatten out in some countries. The adaptation of surgical and procedural steps for a risk-minimizing management of potential COVID-19-positive patients seeking to undergo elective aesthetic procedures in the wake of that wave will present the next big challenge for the aesthetic surgery community. We propose a clinical algorithm to enhance patient safety in elective surgery in the context of COVID-19 and to minimize cross-contamination between healthcare workers and patients. New evidence-based guidelines regarding surgical risk stratification, testing, and clinical flow management/contamination management are proposed. We believe that only the continuous development and broad implementation of guidelines like the ones proposed in this paper will allow an early reintegration of all aesthetic procedures into the scope of surgical care currently performed and to prepare the elective surgical specialties better for a possible second wave of the pandemic.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Equation of state and critical point behavior of hard-core double-Yukawa fluids

A theoretical study on the equation of state and the critical point behavior of hard-core double-Yukawa fluids is presented. Thermodynamic perturbation theory, restricted to first order in the inverse temperature and having the hard-sphere fluid as the reference system, is used to derive a relatively simple analytical equation of state of hard-core multi-Yukawa fluids. Using such an equation of state, the compressibility factor and phase behavior of six representative hard-core double-Yukawa fluids are examined and compared with available simulation results. The effect of varying the parameters of the hard-core double-Yukawa intermolecular potential on the location of the critical point is also analyzed using different perspectives. The relevance of this analysis for fluids whose molecules interact with realistic potentials is also pointed out.

Treatment-related morbidity in atypical teratoid/rhabdoid tumor: multifocal necrotizing leukoencephalopathy

BACKGROUND

Atypical teratoid/rhabdoid tumor (AT/RT) is an aggressive malignant brain tumor that, since it was first identified, has been treated with aggressive treatment regimens, e.g. high-dose chemotherapy with stem cell rescue and early radiotherapy. We reviewed our experience because of concerns with respect to treatment-related toxicity in our patients.

METHODS

Seven patients with a median age at presentation of 18 months were diagnosed with AT/RT between 1996 and 2006. Tumor location was supratentorial in 2 patients, in the posterior fossa in 4 and spinal in 1. Gross total resection was performed in 1 patient, subtotal resection in 5 and biopsy only in 1. Adjuvant treatment consisted of chemotherapy and radiotherapy in 5 patients.

RESULTS

Median progression-free survival was 4 months, and median overall survival was 7 months. Two children are alive at 44 and 102 months. Significant surgical and chemotherapy-related morbidity was seen. Biopsy-proven multifocal necrotizing leukoencephalopathy (MNL) was seen in one patient who is alive 44 months after diagnosis. Another patient who was thought to have recurrent tumor in the brainstem 9 months after diagnosis had imaging findings compatible with MNL.

CONCLUSION

Although improving results are reported for AT/RT using intensive treatment regimens, treatment-related morbidity is considerable in this young patient population.

Six-Minute Walk Test demonstrates motor fatigue in spinal muscular atrophy

BACKGROUND

In spinal muscular atrophy (SMA), weakness, decreased endurance, and fatigue limit mobility. Scales have been developed to measure function across the wide spectrum of disease severity. However, these scales typically are observer dependent, and scores are based on sums across Likert-scaled items. The Six-Minute Walk Test (6MWT) is an objective, easily administered, and standardized evaluation of functional exercise capacity that has been proven reliable in other neurologic disorders and in children.

METHODS

To study the performance of the 6MWT in SMA, 18 ambulatory participants were evaluated in a cross-sectional study. Clinical measures were 6MWT, 10-m walk/run, Hammersmith Functional Motor Scale-Expanded (HFMSE), forced vital capacity, and handheld dynamometry. Associations between the 6MWT total distance and other outcomes were analyzed using Spearman correlation coefficients. A paired t test was used to compare the mean distance walked in the first and sixth minutes.

RESULTS

The 6MWT was associated with the HFMSE score (r = 0.83, p < 0.0001), 10-m walk/run (r = -0.87, p < 0.0001), and knee flexor strength (r = 0.62, p = 0.01). Gait velocity decreased during successive minutes in nearly all participants. The average first minute distance (57.5 m) was significantly more than the sixth minute distance (48 m) (p = 0.0003).

CONCLUSION

The Six-Minute Walk Test (6MWT) can be safely performed in ambulatory patients with spinal muscular atrophy (SMA), correlates with established outcome measures, and is sensitive to fatigue-related changes. The 6MWT is a promising candidate outcome measure for clinical trials in ambulatory subjects with SMA.

[Characteristics of metastatic prostate cancer occurring in patients under 50 years of age]

OBJECTIVE

To identify the clinical features, diagnostic approach, and treatment of metastatic prostate cancer in young adult patients.

METHODS

A retrospective review was made of the clinical histories of patients under 50 years of age diagnosed with prostate cancer at the urology department of the National Institute for Neoplastic Diseases from 1952 to 2005. Demographic characteristics and data on history, symptoms, diagnostic procedures, treatment, and disease course were collected. Data were statistically analyzed and compared to information obtained from a literature search.

RESULTS

There were 69 patients aged less than 50 years who had been diagnosed with prostate cancer, 60% of whom had metastatic tumors. Mean patient age was 45.5 years, with a lower range of 29. All patients reported bone pain, associated to other signs and symptoms such as spinal cord compression (19.5%), lower limb edema (17%), peripheral adenopathies (36.5%), and abdominal tumor (2.4%). All patients had bone metastases, of which 14.6% were in solid organs (lung and liver), 48.7% in retroperitoneum, and 7.3% in mediastinum. Initially, three patients were diagnosed a lymphoproliferative syndrome, one patient a retroperitoneal tumor of unknown etiology, and four patients a metastasis from an unknown primary tumor. Mean prostate-specific antigen (PSA) level was 795 ng/mL (3-6500). All pathologies were reported as poorly differentiated or undifferentiated. Mean survival was 16.1 months (1-84), and all patients died due to disease progression.

CONCLUSIONS

Advanced prostate cancer is an uncommon condition in young adults. Its clinical presentation is atypical, as metastases may mimic other diseases. The course of disease is indolent, and prognosis is poor. In patients with risk factors, PSA testing should be started before 50 years of age.

Rehabilitation in Social Cognition for Bipolar Patients: A State of the Art

Deficits in social cognition have been reported in euthymic bipolar patients. Thus, these deficits could be determining the disability observed in these patients for achieving the functionality expected at work or in sociability. In this way, there is a need for specific programs of rehabilitation in social cognition in bipolar disorder. Unfortunately, there is a paucity of programmes designed for improving social cognition in bipolar patients. A review of these programmes will be presented.

Expression of SEAP (secreted alkaline phosphatase) by baculovirus mediated transduction of HEK 293 cells in a hollow fiber bioreactor system

A BacMam baculovirus was designed in our laboratory to express the reporter protein secreted alkaline phosphatase (SEAP) driven by the immediate early promoter of human cytomegalovirus promoter (CMV). In vitro tests have been carried out using this recombinant baculovirus to study the secreted protein in two cell lines and under various culture conditions. The transductions were carried out on two commonly used mammalian cell lines namely the human embryonic kidney (HEK 293A) and Chinese hamster ovary (CHO-K1). Initial studies clearly demonstrated that the transient expression of SEAP was at least 10-fold higher in the HEK 293 cells than the CHO cells under equivalent experimental conditions. Factorial design experiments were done to study the effect of different parameters such as cell density, MOI, and the histone deacetylase inhibitor, trichostatin A concentration. The multiplicity of infection (MOI) and the cell density were found to have the most impact on the process. The enhancer trichostatin A also showed some positive effect. The production of secreted protein in a batch reactor was studied using the Wave disposable bioreactor system. A semi-continuous perfusion process was developed to extend the period of gene expression in mammalian cells using a hollow fiber bioreactor system (HFBR). The growth of cells and viability in both systems was monitored by offline analyses of metabolites. The expression of recombinant protein could be maintained over an extended period of time up to 30 days in the HFBR.

Quantitative objective markers for upper and lower motor neuron dysfunction in ALS

OBJECTIVE

To investigate the value of objective biomarkers for upper (UMN) and lower (LMN) motor neuron involvement in ALS.

METHODS

We prospectively studied 64 patients with ALS and its subsets using clinical measures, proton MR spectroscopic imaging ((1)H MRSI), diffusion tensor imaging, transcranial magnetic stimulation, and the motor unit number estimation (MUNE) at baseline and every 3 months for 15 months and compared them with control subjects.

RESULTS

(1)H MRSI measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration were markedly reduced in ALS (p = 0.009) and all UMN syndromes combined (ALS, familial ALS [fALS], and primary lateral sclerosis; p = 0.03) vs control values. Central motor conduction time to the tibialis anterior was prolonged in ALS (p < 0.0005) and combined UMN syndromes (p = 0.001). MUNE was lower in ALS (p < 0.0005) and all LMN syndromes combined (ALS, fALS, and progressive muscular atrophy; p = 0.001) vs controls. All objective markers correlated well with the ALS Functional Rating Scale-Revised, finger and foot tapping, and strength testing, suggesting these markers related to disease activity. Regarding changes over time, MUNE changed rapidly, whereas neuroimaging markers changed more slowly and did not significantly differ from baseline.

CONCLUSIONS

(1)H MR spectroscopic imaging measures of the primary motor cortex N-acetyl-aspartate (NAA) concentration and ratio of NAA to creatine, central motor conduction time to the tibialis anterior, and motor unit number estimation significantly differed between ALS, its subsets, and control subjects, suggesting they have potential to provide insight into the pathobiology of these disorders.

Development and evaluation of a self-administered version of the ALSFRS-R

We evaluated the reliability and sensitivity to change over time of a newly developed self-administered version of the ALS functional rating scale-revised (ALSFRS-R) in 60 consecutive patients from an ALS clinic. The self-administered ALSFRS-R showed excellent reliability (intraclass correlation = 0.93, 95% CI: 088 to 0.96) and similar sensitivity to change over time vs the standard evaluator-administered ALSFRS-R.