Functional expression of the eotaxin receptor CCR3 in CD30+ cutaneous T-cell lymphoma

Little is known about mechanisms involved in skin-specific homing of cutaneous T-cell lymphoma (CTCL). Chemokine/chemokine receptor interactions have been implicated in the homing of lymphoma cells to various tissue sites. We investigated tissue samples and tumor cell suspensions of patients with CD30(+) CTCL (n = 8) and CD30(-) CTCL (mycosis fungoides, n = 6; Sézary syndrome, n = 6) for expression of the chemokine receptors CCR3, CCR4, and CCR8 and the CCR3 ligands eotaxin/CCL11, monocyte chemoattractant protein 3 (MCP-3)/CCL7, and RANTES (regulated on activation, normal T expressed and secreted)/CCL5. Of 8 CD30(+) CTCLs, 7 expressed CCR3, 4 CCR4, and none CCR8. CCR3 expression was not found in skin tissue samples from 12 CD30(-) CTCLs. Coexpression of CCR3 and CD30 was demonstrated by flow cytometry in tumor cell suspensions. Internalization experiments demonstrated functionality of CCR3 expressed by freshly isolated tumor cells. Actin polymerization as well as migration in response to eotaxin was demonstrated in a CD30(+) cutaneous lymphoma cell line. CCR3 ligand eotaxin/CCL11 was detected in lesional skin of CD30(+) CTCL by immunohistochemistry, preferentially in tumor cells. Eotaxin/CCL11 expression in tumor cells was confirmed by intracellular immunofluorescence. Analysis of cytokine expression pattern of CCR3-bearing infiltrating cells showed a predominance of interleukin-4 (IL-4) but not interferon-gamma (IFN-gamma) protein expression,1 consistent with a T-helper 2 (Th-2) profile. These results suggest that expression of CCR3 and its ligand eotaxin/CCL11 plays a role in the recruitment and retention of CD30(+) malignant T cells to the skin.     

Role of the coronary sinus in maintenance of atrial fibrillation

INTRODUCTION: Bursts of tachycardia arising in the pulmonary veins may play an important role in perpetuating atrial fibrillation (AF). However, the role of the coronary sinus (CS) in the perpetuation of AF has been unclear. The aim of this study was to determine whether the CS plays a role in perpetuation of AF. METHODS AND RESULTS: Pulmonary vein isolation was performed by segmental ostial ablation with radiofrequency energy in 22 consecutive patients with paroxysmal AF. Bipolar and unipolar electrograms recorded in the left atrium and CS were analyzed during atrial pacing from the mitral annulus and during AF. There was a mean of 2.5 +/- 0.5 electrical connections between the CS and the left atrium. The electrical connections between the left atrium and CS were ablated with a mean of 6.2 +/- 2.7 minutes of radiofrequency energy applied along the atrial side of the inferior mitral annulus. During AF, episodes of intermittent tachycardia alternated between the left atrium and the CS. Among the 22 patients, sustained AF was still inducible in 9 after pulmonary vein isolation. After electrical disconnection of the CS from the left atrium, sustained AF was inducible in only 3 of these 9 patients. CONCLUSION: The CS may be a source of rapid repetitive electrical activity during AF. The lower probability of inducible sustained AF after electrical disconnection of the CS from the left atrium suggests that the CS may play a role in perpetuating AF.     

Production and characterization of human monoclonal anti-idiotype antibodies to anti-dsDNA antibodies

Anti-dsDNA autoantibodies are the hallmark of systemic lupus erythematosus (SLE) and frequently correlate with disease activity. In this study we report the isolation and characterization of human anti-Id monoclonal antibody fragments as single-chain Fv fragments (scFv) against anti-dsDNA antibody. The anti-Id monoclonal antibodies, specific for anti-dsDNA antibodies, have been cloned from phage display antibody scFv libraries derived from a patient with SLE. The V gene repertoires were derived from the RNA obtained from the B cells of an SLE patient with anti-Ro/SSA and anti-La/SSB antibodies. Affinity-purified anti-dsDNA antibodies were used for selection of bacterial clones producing specific scFv antibody fragments against anti-dsDNA antibodies and little reactivity with normal IgG and other IgG antibodies by ELISA. The anti-Id antibody recognizes a public idiotope that is broadly cross-reactive with polyclonal and monoclonal anti-dsDNA antibodies. This binding was largely inhibited by dsDNA antigen. The anti-Id antibody inhibited anti-dsDNA binding to dsDNA antigen in immunoassays and in the Crithidia luciliae assay. The anti-Id scFv antibody fragments derived from human genes could modulate the pathogenicity of anti-dsDNA autoantibodies and may have therapeutic implications in SLE. They may also be used as probes in studies of the structure of the idiotype.     

Clinical utility of EUS-guided fine-needle aspiration of mediastinal masses in the absence of known pulmonary malignancy

BACKGROUND: Mediastinal masses represent a diagnostic challenge because of their proximity to numerous critical structures, difficulty of access for tissue sampling, and myriad potential pathologic etiologies. A large, single-center experience with EUS-guided fine-needle aspiration (EUS-FNA) in the diagnosis of non-lung cancer-related mediastinal masses is presented. METHODS: An EUS database was reviewed and all cases of mediastinal mass or lymphadenopathy encountered between 1994 and 1999 were included. Final diagnoses were determined by EUS-FNA cytology and clinical follow-up. RESULTS: Forty-nine patients were identified (27 women, 22 men; mean age 58.1 years, range 30-89 years). A malignant process was diagnosed in 22 cases (45%) and a benign process in 24 (49%). The EUS-FNA specimen was nondiagnostic in 3 cases (6%). An accurate diagnosis was made in 46 of the 49 patients (94%). No complication was noted. CONCLUSIONS: EUS-FNA is a minimally invasive technique that facilitates detection and tissue sampling of mediastinal masses. It is a safe procedure that can be performed with the patient under conscious sedation in an outpatient setting.     

Imaging techniques for muscle injury in sports medicine and clinical relevance

Magnetic resonance imaging (MRI) and ultrasound are the imaging modalities of choice to assess muscle injuries in athletes. Most authors consider MRI as the reference standard for evaluation of muscle injuries, since it superiorly depicts the extent of injuries independently of its temporal evolution, and due to the fact that MRI seems to be more sensitive for the detection of minimal injuries. Furthermore, MRI may potentially allow sports medicine physicians to more accurately estimate recovery times of athletes sustaining muscle injuries in the lower limbs, as well as the risk of re-injury. However, based on data available, the specific utility of imaging (including MRI) regarding its prognostic value remains limited and controversial. Although high-quality imaging is systematically performed in professional athletes and data extracted from it may potentially help to plan and guide management of muscle injuries, clinical (and functional) assessment is still the most valuable tool to guide return to competition decisions.     

Macro-optical trapping for sample confinement in light sheet microscopy

Light sheet microscopy is a powerful approach to construct three-dimensional images of large specimens with minimal photo-damage and photo-bleaching. To date, the specimens are usually mounted in agents such as agarose, potentially restricting the development of live samples, and also highly mobile specimens need to be anaesthetized before imaging. To overcome these problems, here we demonstrate an integrated light sheet microscope which solely uses optical forces to trap and hold the sample using a counter-propagating laser beam geometry. Specifically, tobacco plant cells and living Spirobranchus lamarcki larvae were successfully trapped and sectional images acquired. This novel approach has the potential to significantly expand the range of applications for light sheet imaging.OCIS codes: (110.0180) Microscopy, (110.0110) Imaging systems, (180.6900) Three-dimensional microscopy, (350.4855) Optical tweezers or optical manipulation     

Multimodal fiber source for nonlinear microscopy based on a dissipative soliton laser

Recent developments in high energy femtosecond fiber lasers have enabled robust and lower-cost sources for multiphoton-fluorescence and harmonic-generation imaging. However, picosecond pulses are better suited for Raman scattering microscopy, so the ideal multimodal source for nonlinear microcopy needs to provide both durations. Here we present spectral compression of a high-power femtosecond fiber laser as a route to producing transform-limited picosecond pulses. These pulses pump a fiber optical parametric oscillator to yield a robust fiber source capable of providing the synchronized picosecond pulse trains needed for Raman scattering microscopy. Thus, this system can be used as a multimodal platform for nonlinear microscopy techniques.OCIS codes: (320.7140) Ultrafast processes in fibers, (180.5655) Raman microscopy, (190.4970) Parametric oscillators and amplifiers     

From the Cover: COVID-19 lockdown induces disease-mitigating structural changes in mobility networks

In the wake of the COVID-19 pandemic many countries implemented containment measures to reduce disease transmission. Studies using digital data sources show that the mobility of individuals was effectively reduced in multiple countries. However, it remains unclear whether these reductions caused deeper structural changes in mobility networks and how such changes may affect dynamic processes on the network. Here we use movement data of mobile phone users to show that mobility in Germany has not only been reduced considerably: Lockdown measures caused substantial and long-lasting structural changes in the mobility network. We find that long-distance travel was reduced disproportionately strongly. The trimming of long-range network connectivity leads to a more local, clustered network and a moderation of the “small-world” effect. We demonstrate that these structural changes have a considerable effect on epidemic spreading processes by “flattening” the epidemic curve and delaying the spread to geographically distant regions.

During the first phase of the coronavirus disease 2019 (COVID-19) pandemic, countries around the world implemented a host of containment policies aimed at mitigating the spread of the disease (1–4). Many policies restricted human mobility, intending to reduce close-proximity contacts, the major driver of the disease’s spread (5). In Germany, these policies included border closures, travel bans, and restrictions of public activity (school and business closures), paired with appeals by the government to avoid trips voluntarily whenever possible (6). We refer to these policies as “lockdown” measures for brevity.Based on various digital data sources such as mobile phone data or social media data, several studies show that mobility significantly changed during lockdowns (7). Most studies focused on general mobility trends and confirmed an overall reduction in mobility in various countries (8–12). Other research focused on the relation between mobility and disease transmission: For instance, it has been argued that mobility reduction is likely instrumental in reducing the effective reproduction number in many countries (13–17), in agreement with theoretical models and simulations, which have shown that containment can effectively slow down disease transmission (18–20).However, it remains an open question whether the mobility restrictions promoted deeper structural changes in mobility networks and how these changes impact epidemic spreading mediated by these networks. Recently, Galeazzi et al. (21) found increased geographical fragmentation of the mobility network. A thorough understanding of how structural mobility network changes impact epidemic spreading is needed to correctly assess the consequences of mobility restrictions not only for the current COVID-19 pandemic, but also for similar scenarios in the future.Here, we analyze structural changes in mobility patterns in Germany during the COVID-19 pandemic. We analyze movements recorded from mobile phones of 43.6 million individuals in Germany. Beyond a general reduction in mobility, we find considerable structural changes in the mobility network. Due to the reduction of long-distance travel, the network becomes more local and lattice-like. Most importantly, we find a changed scaling relation between path lengths and geographic distance: During lockdown, the effective distance (and arrival time in spreading processes) to a destination continually grows with geographic distance. This shows a marked reduction of the “small-world” characteristic, where geographic distance is usually of lesser importance in determining path lengths (22, 23). Using simulations of a commuter-based susceptible-infected-removed (SIR) model, we demonstrate that these changes have considerable practical implications as they suppress (or “flatten”) the curve of an epidemic remarkably and delay the disease’s arrival between distant regions.     

The effect of lithium on growth factor production in long-term bone marrow cultures

We have previously reported that lithium chloride (LiCl) stimulates the production of granulocyte-macrophage colony-forming cells (GM-CFC), pluripotent stem cells (CFU-S), and differentiated granulocytes, macrophages and megakaryocytes in murine Dexter marrow cultures and that this effect appears to be mediated indirectly by a radioresistant adherent marrow cell. In this study we have established that exposure of murine Dexter cultures to LiCl (4 mEq/L) causes an increase of colony-forming cell megakaryocytes (CFU-meg) over 1 to 6 weeks of culture in both supernatant (188% to 611%) and stromal phases (123% to 246%). Moreover, we have shown that lithium treatment of either irradiated (1,100 rad) or unirradiated stromal cells increased production of activities stimulating formation of megakaryocyte, granulocyte, macrophage, and mixed lineage colonies and proliferation of the factor-dependent cell line, FDC-P1. This FDC-P1 stimulatory activity was completely blocked by an antibody to purified recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF). The baseline or lithium-induced--stromal-derived bone marrow colony stimulating activity was partially blocked by the antibody to rGM-CSF and by an antibody to purified colony stimulating factor I (CSF-1); the two antibodies combined resulted in greater than 90% inhibition of the lithium-induced marrow stimulatory activity. In addition, radioimmunoassay (RIA) showed that although CSF-1 was detectable in supernatants of these cultures, exposure to lithium did not increase CSF-1 levels. These data indicate that Dexter stromal cells produce CSF- 1 and GM-CSF and that lithium appears to exert its stimulatory effects on in vitro myelopoiesis by inducing production of GM-CSF.