Associations of sleep-related variables with reverse dipping patterns of blood pressure in α-synucleinopathies.

INTRODUCTION: The reverse dipping blood pressure (BP) pattern is very common in α-synucleinopathies. We aimed to explore the associations of sleep-related variables with abnormal BP circadian rhythms in Parkinson's disease (PD) and multiple system atrophy (MSA). METHODS: A total of 126 patients, 76 with PD and 50 with MSA, were included. All participants underwent ambulatory BP monitoring and full-night polysomnography (PSG). We analyzed abnormal dipping patterns and sleep-related parameters, including moderate to severe obstructive sleep apnea (OSA), rapid eye movement behavior disorder (RBD), average oxygen saturation (SaO2%), lowest SaO2%, duration of SaO2% <90%, and apnea-hypopnea index (AHI). Binary logistic regression was performed to explore the associations between paraclinical variables, sleep-related variables, and reverse dipping patterns. RESULTS: Reverse dipping patterns were predominant in patients with PD (58.5 %) and MSA (68.0 %). Patients with MSA had higher AHI, RBD, and lower average SaO2% than those with PD. Taking both diseases together as a whole group of α-synucleinopathies, logistic regression analysis indicates the Hoehn-Yahr stage (odds ratio [OR] = 2.00 for reverse systolic and 2.34 for reverse diastolic dipping patterns), moderate to severe OSA (OR = 2.71 for reverse systolic and 2.53 for reverse diastolic dipping patterns), average SaO2% (OR = 1.35 for reverse systolic dipping patterns), and male sex (OR = 2.70 for reverse diastolic dipping patterns) were independently associated with reverse dipping patterns. CONCLUSIONS: Reverse dipping patterns were common in patients with PD and MSA. Hoehn-Yahr stage, moderate to severe OSA, average SaO2%, and male sex were associated with reverse dipping patterns in α-synucleinopathy.

Effects of water salinity on the multi-angular polarimetric properties of light reflected from smooth water surfaces.

Salinity is an important environmental factor regulating the aquatic system structure of lakes and other water bodies. Changes in salinity, which can be caused by human activities, can adversely impact the life of water organisms. The refractive index, which can be directly related to water salinity, also controls the polarimetric properties of light reflected from the water surface. In this study, polarimetric measurements of smooth water surfaces with different salinity content were performed at different viewing zenith angles in the wavelength range of 450-1000 nm in the specular reflection directions. The results show that the light reflected from the water surface (defined as reflectance factor) in one measurement direction can be replaced by the reflectance factor derived from polarimetric measurements, and if the polarizer absorptance is considered, the average relative difference is less than 3%. The degree of linear polarization (DOLP) was used to retrieve the refractive indices of water with different salinities based on the Fresnel reflection coefficient. The inverted refractive indices not only have high accuracy (uncertainty from 0.9% to 1.8%) but also have a very strong relationship with the water salinity content. Our study shows the possibility of estimating the variation in water salinity using multi-angular polarimetric measurements.

China's NMPA perspective on the clinical performance of SARS-CoV-2 antigen test reagents.

The COVID-19 pandemic continues to spread all over the world. In the process of emergency use authorization, the Center for Medical Device Evaluation of the China National Medical Products Administration issued 'Key Points of Technical Review for the Registration of SARS-CoV-2 Antigen/Antibody Detection Reagents' as the guidance of registration of antigen and antibody test reagents for the industry. In this document, clinical evaluation requirements of antigen detection reagents are elaborated. Based on the Key Points document and the authors' review practice, this article explains the evaluation methods and requirements of clinical performance of SARS-CoV-2 antigen-detecting rapid diagnostic tests, then analyzes the application scenarios and intended use of antigen detection reagents.

Key points of technical review for the registration of SARS-CoV-2 antigen/antibody tests.

Coronavirus disease-2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread globally since its first report and become a worldwide pandemic. In response to the outbreak of COVID-19, Center for Medical Device Evaluation, NMPA (CMDE) initiated emergency review and approval procedures to accelerate the process of reviewing emergent medical products and issued the Key Points of Technical Review for the Registration of SARS-CoV-2 Antigen/Antibody Tests (Key Points) to provide the requirements on the technical review of the tests. With uncontrolled spread and evolution of COVID-19 in the world, continuous prevention and measurements are necessary for fighting this pandemic and SARS-CoV-2 antigen/antibody tests are still urgently needed. This article is an attempt to expand clarification of the Key Points to wider audiences based on current understanding of SARS-CoV-2 to facilitate the development and application of SARS-CoV-2 antigen/antibody tests.

China NMPA perspective on clinical evaluation of SARS-CoV-2 antibody test reagents in the process of emergency approval.

Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 antibody testing an important supplement to nucleic acid testing. In the process of emergency approval, the Center for Medical Device Evaluation of the China National Medical Products Administration released The Key Points of Technical Review for the Registration of SARS-CoV-2 Antigen/Antibody Detection Reagents. The Clinical Study Requirement section of the Key Point has put forward requirements in terms of reference methods and subject enrolment among others, which can ensure that the test results can meet the clinical needs. This article draws on the experience of the China NMPA in evaluating diagnostic reagents used to supplement the gold standard test method in the early stage of an epidemic of an infectious disease, as well as to serve as reference for clinicians and regulators.

Comparison and application of different immunoassay methods for the detection of SARS-CoV-2.

The detection data of IgM and IgG antibodies in 169 patients with coronavirus disease-2019 (COVID-19) were analyzed to evaluate differences in clinical performance between the colloidal gold method and chemiluminescence method. In this study, chemiluminescence detection of IgM antibody showed a positive conversion earlier (about 1-2 days earlier), positive conversion rates higher in different stages of disease, and a trend of declining positive rate later than colloidal gold method. For IgG antibody, the chemiluminescence method showed a positive conversion earlier and the positive rate climbing more quickly than the colloidal gold method. No obvious negative-converting tendency of IgG detection was observed within 35 days after the onset of disease. Although colloidal gold method is generally less sensitive than chemiluminescence method, it shows advantages of shorter turn-around time, more simple procedure, and no special equipment required. The two methodologies can be chosen according to different laboratory conditions. A reasonable understanding of the performance of reagents with different methodologies can help in clinical disease diagnosis effectively and assist in the diagnosis of the progression of COVID-19, for which the dynamic changes of antibody will provide reliable evidence.

Photopolarimetric properties of a manmade target over a wide range of measurement directions.

The optical scattering property of a target is the essential signal for passive remote sensing. In this study, we performed the photopolarimetric measurements of a manmade target in the wavelength range of 400-1000 nm over the hemispherical directions using the Northeast Normal University Laboratory Goniospectrometer System (NENULGS). We discussed the influence of the absorption of a polarizer on the measured Stokes parameters, and used the BRF (bidirectional reflectance factor) and BPRF (bidirectional polarized reflectance factor) to characterize the scattering property of our sample at selected wavelengths. These measured BRFs and BPRFs were also compared with the modeled results using a semi-empirical photometric model and a semi-empirical polarimetric model, respectively. Subsequently, the modeled BRFs and BPRFs were used to simulate the degree of linear polarization (DoLP) of a man-made target, which provided a comparison with the measured DoLP. We found that (1) the I parameter reflectance factor (IpRF) can effectively represent the BRF if we considered the absorption of the polarizer, (2) the modeled photopolarimetric results of manmade target were in good agreement with the measurements, and (3) the simulated DoLP of manmade target also provided a good match with the measured DoLP, with an average relative difference of approximately 0.2 for all the selected wavelengths. Our results appeared very promising for proving that the polarimetric measurement is a very effective and useful method for remote sensing applications as well as deepening our understanding of the optical properties of reflected light from the manmade object as ours.

Effects of particle size on bidirectional reflectance factor measurements from particulate surfaces.

The bidirectional reflectance factor (BRF) is commonly used to study the structure of a particulate surface based on photometric measurements. In this paper, we describe the bidirectional reflectance factor distribution of natural particulate surfaces with particles sizes varying from 0.15 mm to 0.9 mm. Two types of natural particulate surfaces (one with low reflectance and the other with moderate reflectance) were measured at visible and near-infrared wavelengths using the Northeast Normal University Laboratory Goniospectrometer System (NENULGS). Both the BRFs and anisotropic reflectance factors (ARFs) at selected wavelengths were compared with previously published results to verify the accuracy of our measurements, and we also quantitatively analyzed the effects of particle size on the BRF. It was found that the maximum reflectance difference, which was more distinct for the low-reflectance samples, between particulate surfaces with particle sizes of 0.15 mm and 0.9 mm occurred in the forward scattering direction for all samples, and the value of this maximum difference reached 59% for the low-reflectance samples. Then, we conducted a test of a photometric model to determine which parameters could be confidently linked to the surfaces' reflectance behavior. The inverted parameters were compared with the known physical parameters of our samples, such as the particle size. We found that the single-scattering albedo could be empirically used to determine the particle sizes of our samples when measurements of particulate surfaces with different particle sizes were performed under the same incidence conditions and with wide viewing angles. The potential applications of our results appear very promising for empirically resolving the spatial distribution of particle size within a given particulate sample as well as for deepening our understanding of the scattering properties of particulate media.

Determination of mildronate in human plasma and urine by liquid chromatography-tandem mass spectrometry.

A sensitive and selective analytical method based on liquid chromatography-triple-quadrupole mass spectrometer has been developed to determine mildronate in human plasma and urine. The aim of this work was to find a valid method to study the pharmacokinetic profiles of mildronate in humans. Mildronate is a heart protection medicine, a carnitine's structural analogue, so levocarnitine was used as an internal standard for quantification. Under the electrospray ionization source positive ion mode, calibration curves with good linearities (r=0.9998 for plasma sample and r=0.9999 for urine sample) were obtained in the range of 1.0-20,000 ng ml(-1) for mildronate. The detection limit was 1 ng ml(-1). Recoveries were around 90% for the extraction from human plasma, and good precision and accuracy were achieved. This method is feasible for the evaluation of pharmacokinetic profiles of mildronate in humans, and to the best of our knowledge, this is the first report on LC-MS-MS analysis of mildronate in plasma and urine.