SARS-CoV-2 versus other minor viral infection on kidney injury in asymptomatic and mildly symptomatic patients.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has become a global pandemic since December 2019. Most of the patients are mild or asymptomatic and recovered well as those suffered from other respiratory viruses. SARS-CoV-2 infection is supposed to demonstrate more sequelae. Acute kidney injury (AKI) is common among COVID-19 patients and is associated with disease severity and outcomes. Only a few studies focused on a detailed analysis of kidney damage in asymptomatic or mildly symptomatic COVID-19 patients. Whether any minor viral infection is likely to exhibit similar minor effect on renal function as COVID-19 is still unclear, and the definite pathophysiology of viral invasion is not fully understood. Currently, the proposed mechanisms of AKI include direct effects of virus on kidney, dysregulated immune response, or as a result of multi-organs failure have been proposed. This study will discuss the difference between COVID-19 and other viruses, focusing on proposed mechanisms, biomarkers and whether it matters with clinical significance.

Mortality rate of end-stage kidney disease patients in Taiwan.

BACKGROUND/PURPOSE: End-stage kidney disease (ESKD) is a global burden that reflects each country's unique condition. We used the National Health Insurance Research Database (NHIRD) of Taiwan to decipher changes in the mortality and international survival rates and to determine the effectiveness of the pre-end-stage renal disease care program (pre-ESRD care program) to guide future health policies for ESKD. METHODS: We conducted a retrospective cohort analysis of the NHIRD data along with records from the catastrophic illness certificate program of ESKD patients from 2010 to 2018. RESULTS: From 2010 to 2018, the annual dialysis-related mortality rate in Taiwan increased from 10.6 to 11.8 deaths per hundred patient-years. The mortality rate for patients below 40 years appears to be decreasing, reflecting the improved quality of care for ESKD patients. Patients above 75 years showed increasing mortality, indicating the prolonged survival and aging of the ESKD population. Patients undergoing dialysis who participated in the pre-ESRD care program had a higher post-dialysis initiation life expectancy than those who did not participate. Among the program enrollees, the post-dialysis initiation life expectancy was higher in patients who had participated for more than one year. Taiwan has one of the highest ESKD patient survival rates globally. CONCLUSION: From 2010 to 2018, the reduced mortality in young patients and aging of the ESKD population might indicate that the quality of care in Taiwan for ESKD has improved. Furthermore, a better survival rate after dialysis initiation was observed in the pre-ESRD care program participants.

Dendrocorticiopsisorientalis gen. et sp. nov. of the Punctulariaceae (Corticiales, Basidiomycota) revealed by molecular data.

Dendrocorticiopsisorientalis is presented in this study as a new genus and new species based on morphological and phylogenetic evidence. This new taxon is characterized by resupinate, smooth and membranaceous basidiomata, monomitic hyphal system with clamps, colorless dendrohyphidia, variable presence of cystidia, and ellipsoid to ovoid basidiospores measuring 5-7 × 3.2-5.2 µm. The phylogenetic analyses based on the ITS1-5.8S-ITS2 (ITS) + nuclear 28S rDNA (28S) dataset of Corticiales indicated that the new taxon is nested in Punctulariaceae, separated from other genera with strong support values. Descriptions, specimen photo, and illustrations of the new taxon are provided in this study. A morphological comparison of the four genera of Punctulariaceae is given.

Sanghuangporus toxicodendri sp. nov. (Hymenochaetales, Basidiomycota) from China.

Sanghuangporus toxicodendri (Hymenochaetales) is described as new based on collections made from Shennongjia Forestry District, Hubei Province, China. All studied basidiocarps grew on living trunks of Toxicodendron sp. This new species is characterized by having perennial, effused-reflexed to pileate basidiocarps; pore surface brownish yellow or yellowish brown, pores 7-9 per mm; context 1-5 mm thick or almost invisible; setae ventricose, dark brown, 26-42 × 7-10 µm; basidia 4-sterigmate or occasionally 2-sterigmate; basidiospores broadly ellipsoid, smooth, brownish yellow, slightly thick-walled, mostly 3.5-4 × 2.8-3 µm. Maximum likelihood and Bayesian inference phylogenies inferred from internal transcribed spacer (ITS) region of rDNA indicated that Sanghuangporus spp. formed a monophyletic clade and resolved as a sister to Tropicoporus spp., and six strains of S. toxicodendri formed a monophyletic group which is sister to S. quercicola. An identification key to known species of Sanghuangporus is provided.

Four new East Asian species of Aleurodiscus with echinulate basidiospores.

Four new species of Aleurodiscus sensu lato with echinulate basidiospores are described from East Asia: A.alpinus, A.pinicola, A.senticosus, and A.sichuanensis. Aleurodiscusalpinus is from northwest Yunnan of China where it occurs on Rhododendron in montane habitats. Aleurodiscuspinicola occurs on Pinus in montane settings in Taiwan and northwest Yunnan. Aleurodiscussenticosus is from subtropical Taiwan, where it occurs on angiosperms. Aleurodiscussichuanensis is reported from southwest China on angiosperms in montane environments. Phylogenetic relationships of these four new species were inferred from analyses of a combined dataset consisting of three genetic markers, viz. 28S, nuc rDNA ITS1-5.8S-ITS2 (ITS), and a portion of the translation elongation factor 1-alpha gene, TEF1.

Three new species of Phanerochaete (Polyporales, Basidiomycota).

Phanerochaetecanobrunnea, P.cystidiata and P.fusca are presented as new species, supported by morphological studies and two sets of phylogenetic analyses. The 5.8S+nuc 28S+rpb1 dataset shows the generic placement of the three species within the phlebioid clade of Polyporales. The ITS+nuc 28S dataset displays relationships for the new taxa within Phanerochaete s.s. Phanerochaetecanobrunnea grew on angiosperm branches in subtropical Taiwan and is characterised by greyish brown hymenial surface, brown generative hyphae and skeletal hyphae and absence of cystidia. Phanerochaetecystidiata grew on angiosperm branches above 1000 m in montane Taiwan and SW Yunnan Province of China and is characterised by cream to yellowish hymenial surface and more or less encrusted leptocystidia. Phanerochaetefusca grew on angiosperm branches at 1700 m in Hubei Province of China and is characterised by dark brown hymenial surface, leptocystidia, brown subicular hyphae and colourless to brownish basidiospores.

Novel 10-Bit Impedance-to-Digital Converter for Electrochemical Impedance Spectroscopy Measurements.

Electrochemical impedance spectroscopy (EIS) is a widely used technique in biomedical and chemical analysis. A novel 10-bit impedance-to-digital converter (IDC), which can measure and directly convert the magnitude and phase of impedance to digital codes, is proposed for the EIS measurement system. The proposed IDC is composed of a magnitude-to-digital converter (MDC) and a phase-to-digital converter (PDC). The proposed IDC was designed and fabricated using a 0.35 [Formula: see text] 2P4M mixed-signal polycide process, and the core area is only 0.07 mm2. Moreover, it can work over a very wide frequency range (0.1 mHz-100 kHz), and has excellent accuracy. According to the measured results, the DNL of the MDC is within -0.3/+0.3 LSB, and the INL is around -3/+1 LSB. Moreover, an EIS measurement system, which is composed of the proposed IDC chip and some other commercial chips, is built to measure ZoBell's and melatonin solutions for validating the function of the proposed IDC.

Respiration detection chip with integrated temperature-insensitive MEMS sensors and CMOS signal processing circuits.

An airflow sensing chip, which integrates MEMS sensors with their CMOS signal processing circuits into a single chip, is proposed for respiration detection. Three micro-cantilever-based airflow sensors were designed and fabricated using a 0.35 µm CMOS/MEMS 2P4M mixed-signal polycide process. Two main differences were present among these three designs: they were either metal-covered or metal-free structures, and had either bridge-type or fixed-type reference resistors. The performances of these sensors were measured and compared, including temperature sensitivity and airflow sensitivity. Based on the measured results, the metal-free structure with fixed-type reference resistors is recommended for use, because it has the highest airflow sensitivity and also can effectively reduce the output voltage drift caused by temperature change.

Design of a dual-mode electrochemical measurement and analysis system.

A dual-mode electrochemical measurement and analysis system is proposed. This system includes a dual-mode chip, which was designed and fabricated by using TSMC 0.35 µm 3.3 V/5 V 2P4M mixed-signal CMOS process. Two electrochemical measurement and analysis methods, chronopotentiometry and voltammetry, can be performed by using the proposed chip and system. The proposed chip and system are verified successfully by performing voltammetry and chronopotentiometry on solutions.

Does conductance catheter measurement system give consistent and reliable pressure-volume relations in rats?

The conductance catheter technique was developed in the 1980s to measure instantaneous ventricular conductance. After converting measured conductance to volume signals by use of the classic Baan conductance-to-volume equation, real-time pressure-volume (PV) relations can be obtained. A nonlinear conductance-to-volume conversion equation was proposed by Wei in 2005 to improve the accuracy of the conductance catheter system. This study tested the in vivo applicability of the nonlinear conversion equation, particularly focusing on the effect of deviation in catheter position. By altering catheter position, PV loops obtained by using the classic Baan's equation and the nonlinear equation were compared. The comparison results show that the nonlinear equation indeed compensates for the errors introduced by catheter position deviation, and gives more consistent and reliable PV relations. Moreover, the effect of variations in blood resistivity was analyzed. To obtain consistent and reliable PV relations, the nonlinear equation is suggested for use, and changes in blood resistivity should be carefully monitored.

Calibration capacity of the conductance-to-volume conversion equations for the mouse conductance catheter measurement system.

The conductance catheter system is used to measure instantaneous ventricular conductance, and real-time ventricular volume is then determined by converting the measured conductance to volume. Two conductance-to-volume conversion equations for the conductance catheter system have been proposed: Baan's linear equation and Wei's nonlinear equation. In fact, the accuracy of this volume estimation method is limited by several factors, such as the catheter position deviation. The effects of the mouse catheter position deviations on the volume-conductance relationships are investigated with cylindrical finite-element models and mouse left ventricular models. The accuracy and calibration capacity of the two conversion equations for estimating volume are evaluated and compared. According to the comparison results, the performance of the nonlinear conversion equation is better.

Bandwidth measurement of the conductance catheter system.

Conductance catheter system is used to estimate real-time ventricular volume by measuring the time-varying ventricular conductance/admittance. However, the system is generally calibrated only with known resistors, while neither the frequency response nor the bandwidth of the system is calibrated and measured. The main difficulty of measuring its bandwidth is that the sensed signal of the conductance catheter system, which can be viewed as the input of the system, is a modulated signal, rather than a typical sin wave. Therefore, its bandwidth cannot be measured by typical frequency response analyzers, since they are designed for pure sin-wave input. The waveform of the sensed signal is analyzed. Moreover, a waveform simulator designed to mimic the sensed signal is presented. It can be used to measure the bandwidth of conductance catheter system.

Investigation of mouse conductance catheter position deviation effects on volume measurements by finite element models.

The conductance catheter system is used to measure the instantaneous ventricular conductance, and real-time ventricular volumes is then determined by converting the measured conductance to volume. In fact, two different conductance-to-volume conversion equations for conductance catheters have been proposed, the Baan's classic equation and Wei's nonlinear equation. The accuracy of this volume estimation method is limited by several factors, such as the deviation of the catheter position inside the ventricle. The effects of the mouse catheter radial and longitudinal position deviations on the measured conductance are investigated with finite element models. Moreover, the capacities of the two conversion equations to calibrate the error induced by the catheter position variation are evaluated and compared. According to the simulation results, the error-calibrated capacity of the nonlinear conversion equation is better.

Volume catheter parallel conductance varies between end-systole and end-diastole.

In order for the conductance catheter system to accurately measure instantaneous cardiac blood volume, it is necessary to determine and remove the contribution from parallel myocardial tissue. In previous studies, the myocardium has been treated as either purely resistive or purely capacitive when developing methods to estimate the myocardial contribution. We propose that both the capacitive and the resistive properties of the myocardium are substantial, and neither should be ignored. Hence, the measured result should be labeled admittance rather than conductance. We have measured the admittance (magnitude and phase angle) of the left ventricle in the mouse, and have shown that it is measurable and increases with frequency. Further, this more accurate technique suggests that the myocardial contribution to measured admittance varies between end-systole and end-diastole, contrary to previous literature. We have tested these hypotheses both with numerical finite-element models for a mouse left ventricle constructed from magnetic resonance imaging images, and with in vivo admittance measurements in the murine left ventricle. Finally, we propose a new method to determine the instantaneous myocardial contribution to the measured left ventricular admittance that does not require saline injection or other intervention to calibrate.

Impact of physiological variables and genetic background on myocardial frequency-resistivity relations in the intact beating murine heart.

Conductance measurements for generation of an instantaneous left ventricular (LV) volume signal in the mouse are limited, because the volume signal is a combination of blood and LV muscle, and only the blood signal is desired. We have developed a conductance system that operates at two simultaneous frequencies to identify and remove the myocardial contribution to the instantaneous volume signal. This system is based on the observation that myocardial resistivity varies with frequency, whereas blood resistivity does not. For calculation of LV blood volume with the dual-frequency conductance system in mice, in vivo murine myocardial resistivity was measured and combined with an analytic approach. The goals of the present study were to identify and minimize the sources of error in the measurement of myocardial resistivity to enhance the accuracy of the dual-frequency conductance system. We extended these findings to a gene-altered mouse model to determine the impact of measured myocardial resistivity on the calculation of LV pressure-volume relations. We examined the impact of temperature, timing of the measurement during the cardiac cycle, breeding strain, anisotropy, and intrameasurement and interanimal variability on the measurement of intact murine myocardial resistivity. Applying this knowledge to diabetic and nondiabetic 11- and 20- to 24-wk-old mice, we demonstrated differences in myocardial resistivity at low frequencies, enhancement of LV systolic function at 11 wk and LV dilation at 20-24 wk, and histological and electron-microscopic studies demonstrating greater glycogen deposition in the diabetic mice. This study demonstrated the accurate technique of measuring myocardial resistivity and its impact on the determination of LV pressure-volume relations in gene-altered mice.

Nonlinear conductance-volume relationship for murine conductance catheter measurement system.

The conductance catheter system is a tool to determine instantaneous left ventricular volume in vivo by converting measured conductance to volume. The currently adopted conductance-to-volume conversion equation was proposed by Baan, and the accuracy of this equation is limited by the assumption of a linear conductance-volume relationship. The electric field generated by a conductance catheter is nonuniform, which results in a nonlinear relationship between conductance and volume. This paper investigates this nonlinear relationship and proposes a new nonlinear conductance-to-volume conversion equation. The proposed nonlinear equation uses a single empirically determined calibration coefficient, derived from independently measured stroke volume. In vitro experiments and numerical model simulations were performed to verify and validate the proposed equation.

Design of instrumentation and data-acquisition system for complex admittance measurement.

Instantaneous left ventricular volume measurements have been made for many years using a tetrapolar conductance catheter. The main objective is to determine the efficiency of the beating heart, using a tetrapolar catheter inserted in the left ventricle of transgenic mice. The effect of the parallel myocardium contribution must be removed from the total measurement. A dual-frequency technique involving 1 kHz and 100 kHz was chosen because it has been established that the imaginary part (the capacitive reactance) of the complex admittance of the cardiac muscle is much smaller in the lower frequency than at the higher frequency. The design involves generation of an accurate frequency source for both the frequencies careful selection of operational amplifiers for the current conversion stage so that the current is not too large to kill the mouse and that it is capable of performing at high frequencies. The band pass filter stage involved careful design with minimal overlap of the pass bands of both the channels. The overall circuit was designed so that there is minimal shift in the phase due to the circuit elements alone. Work also involved design of GPIB--based data acquisition system using LabVIEW and a digital oscilloscope for effective data acquisition even at high frequencies, which are normally limited by the sampling frequency. This data acquisition system is currently being used in laboratory studies in vivo.

Evidence of time-varying myocardial contribution by in vivo magnitude and phase measurement in mice.

Cardiac volume can be estimated by a conductance catheter system. Both blood and myocardium are conductive, but only the blood conductance is desired. Therefore, the parallel myocardium contribution should be removed from the total measured conductance. Several methods have been developed to estimate the contribution from myocardium, and they only determine a single steady state value for the parallel contribution. Besides, myocardium was treated as purely resistive or mainly capacitive when estimating the myocardial contribution. We question these assumptions and propose that the myocardium is both resistive and capacitive, and its contribution changes during a single cardiac cycle. In vivo magnitude and phase experiments were performed in mice to confirm this hypothesis.