Transitional dendritic cells are distinct from conventional DC2 precursors and mediate proinflammatory antiviral responses

High-dimensional approaches have revealed heterogeneity amongst dendritic cells (DCs), including a population of transitional DCs (tDCs) in mice and humans. However, the origin and relationship of tDCs to other DC subsets has been unclear. Here we show that tDCs are distinct from other well-characterized DCs and conventional DC precursors (pre-cDCs). We demonstrate that tDCs originate from bone marrow progenitors shared with plasmacytoid DCs (pDCs). In the periphery, tDCs contribute to the pool of ESAM+ type 2 DCs (DC2s), and these DC2s have pDC-related developmental features. Different from pre-cDCs, tDCs have less turnover, capture antigen, respond to stimuli and activate antigen-specific naïve T cells, all characteristics of differentiated DCs. Different from pDCs, viral sensing by tDCs results in IL-1β secretion and fatal immune pathology in a murine coronavirus model. Our findings suggest that tDCs are a distinct pDC-related subset with a DC2 differentiation potential and unique proinflammatory function during viral infections.

Variation in Leg Tissue Dielectric Constant Values of Healthy Young Adult Females With and Without Compression Bandaging

Background The clinical efficacy of a compression application has been often limited to the assessment of the change in limb volume, change in clinical symptoms (i.e., wound size, pain, range of motion, incidence of cellulitis), or vascular hemodynamics of the whole limb. Assessing compression-related biophysical changes of a localized area, such as around a wound, or in an area outside of an extremity cannot be objectively assessed by these measurements. Tissue dielectric constant (TDC) values, which provide a measure of the local tissue water (LTW) content, offer an alternative method to document variation in the LTW content of the skin in a specific location. The goals of the present research were (1) to characterize TDC values, expressed as percentage tissue water, from multiple areas along the medial aspect of the lower leg of healthy volunteers and (2) to explore the potential utilization of the TDC values to assess change in tissue water content in a localized area following compression applications. Methods TDC was measured at 10, 20, 30, and 40 cm proximal to the medial malleolus on the medial aspect of the right leg of 18 young adult healthy women with an age range of 18-23 years and a body mass index of 18.7 to 30.7kg/m^2.. TDC was measured at baseline and after 10 minutes of exercise with compression in place on three separate days during which three different compression applications were assessed: a longitudinal elastic stockinette, a two-layer cohesive compression kit, and a combination of the two. Leg circumferences and compression-related interface pressures were also measured. Results Test-Retest Reliability of circumferential measurements and TDC values evaluated using Intraclass correlation coefficient (ICC _3,1) revealed excellent and moderate-to-good reliability, respectively. Analysis of TDC values along the length of the limb using Friedman's test, revealed a small but statistically significant overall difference among baseline TDC values attributable to a smaller value at 40 cm. The largest difference in cumulative average was 7.7% which occurred between 20 and 40 cm, with all other differences between locations less than 1%. No significant differences between the compression applications were observed. Conclusion  The present findings demonstrate the utility of TDC measurements as a modality to assess compression-related changes in the legs of healthy women as a foundation for their potential use in assessing outcomes of compression treatments for persons with lower extremity edema or lymphedema. The absence of a significant change in TDC values in these healthy non-edematous conditions and the demonstrated reliability of the TDC measurements on three different days provides further support for the utility of such applications of TDC measurements. The extension to patients with lower extremity edema or lymphedema needs to be evaluated.

Management Outcome of Adult Thyroglossal Duct Cyst in a General Surgery Tertiary Practice in Sub-Saharan Africa, Nigeria

Thyroglossal duct cyst (TDC) is a rare condition in adults. This is a report of its presentation and standard treatment with good outcome in adults in a Sub-Saharan tertiary hospital. It is a retrospective review of five adult patients who were managed over a five-year period culled from archived records and casenotes. The three males and two females have a median age of 35 years and a range of 15-74 years. Each of them presented with anterior neck masses while one, in addition, had a painful swelling with a discharging sinus. The median duration of the symptoms was 4.5 years. Four of the cysts were in the infrahyoid location and all the patients had a Sistrunk operation. The median duration of follow-up was six months, without complications. Surgeons need to have a high level of suspicion for this condition in adults.

Fast single-cell biochemistry: theory, open source microscopy and applications

Fluorescence lifetime sensing enables researchers to probe the physicochemical environment of a fluorophore providing a window through which we can observe the complex molecular make-up of the cell. Fluorescence lifetime imaging microscopy (FLIM) quantifies and maps cell biochemistry, a complex ensemble of dynamic processes. Unfortunately, typical high-resolution FLIM systems exhibit rather limited acquisition speeds, often insufficient to capture the time evolution of biochemical processes in living cells. Here, we describe the theoretical background that justifies the developments of high-speed single photon counting systems. We show that systems with low dead-times not only result in faster acquisition throughputs but also improved dynamic range and spatial resolution. We also share the implementation of hardware and software as an open platform, show applications of fast FLIM biochemical imaging on living cells and discuss strategies to balance precision and accuracy in FLIM. The recent innovations and commercialisation of fast time-domain FLIM systems are likely to popularise FLIM within the biomedical community, to impact biomedical research positively and to foster the adoption of other FLIM techniques as well. While supporting and indeed pursuing these developments, with this work we also aim to warn the community about the possible shortcomings of fast single photon counting techniques and to highlight strategies to acquire data of high quality.

A Real Time Coincidence System for High Count-Rate TOF or Non-TOF PET Cameras Using Hybrid Method Combining AND-Logic and Time-Mark Technology

A fully digital FPGA-based high count-rate coincidence system has been developed for TOF (Time of Flight) and non-TOF PET cameras. Using a hybrid of AND-logic and Time-mark technology produced both excellent timing resolution and high processing speed. In this hybrid architecture, every gamma event was synchronized by a 125 MHz system clock and generating a trigger associated with a time-mark given by an 8-bit high-resolution TDC (68.3 ps/bin). AND-logic was applied to the synchronized triggers for the real-time raw sorting of coincident events. An efficient FPGA based Time-mark fine-sort algorithm is used to select all the possible coincidence events within the preset coincidence time window. This FPGA-based coincidence system for a modular PET camera offers reprogrammable flexibility and expandability, so the coincidence system is easily employed, regardless of differences in the scale of the PET camera detector setup. A distributed processing method and pipeline technology were adopted in the design to obtain very high processing speed. In this design, both prompt and time-delayed accidental coincidences are simultaneously processed in real time. The real-time digital coincidence system supports coincidence in 2 to 12 detector module setups, capable of processing 72 million single events per second with no digital data loss and captures multiple-event coincidence for better imaging performance evaluation. The coincidence time window-size and time-offset of each coincidence event pair can be programmed independently in 68.3 ps increments (TDC LSB) during the data acquisition in different applications to optimize the signal-to-noise ratio. The complex coincidence system is integrated in one circuit board with 1.5 Gbps fiber optic interface. We demonstrated the system performance using the actual circuit and Monte Carlo simulations.