Clinical diversity and treatment approaches to blastic plasmacytoid dendritic cell neoplasm: a retrospective multicentre study.

BACKGROUND: Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive type of haematologic precursor malignancy primarily often manifesting in the skin. We sought to provide a thorough clinical characterization and report our experience on therapeutic approaches to BPDCN. METHODS: In the present multicentric retrospective study, we collected all BPDCN cases occurring between 05/1999 and 03/2018 in 10 secondary care centres of the German-Swiss-Austrian cutaneous lymphoma working group. RESULTS: A total of 37 BPDCN cases were identified and included. Almost 90% of the patients had systemic manifestations (bone marrow, lymph nodes, peripheral blood) in addition to skin involvement. The latter presented with various types of cutaneous lesions: nodular (in more than 2/3) and bruise-like (in 1/3) skin lesions, but also maculopapular exanthema (in circa 1/6). Therapeutically, 22 patients received diverse combinations of chemotherapeutic regimens and/or radiotherapy. Despite initial responses, all of them ultimately relapsed and died from progressive disease. Eleven patients underwent haematopoietic stem cell transplantation (HSCT; autologous HSCT n = 3, allo-HSCT n = 8). The mortality rate among HSCT patients was only 33.33% with a median survival time of 60.5 months. CONCLUSION: Our study demonstrates the clinical diversity of cutaneous BPDCN manifestations and the positive development observed after the introduction of HSCT.

Molecular classification of tumour cells in a patient with intravascular large B-cell lymphoma.

BACKGROUND: Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal LBCL. It is characterized by the proliferation of tumour cells exclusively intraluminally in small blood vessels of different organs. The clinical manifestation depends on the type of organ affected; additionally, a haemophagocytic syndrome can be observed in some patients. OBJECTIVES: The aim was to further understand the nosology of this lymphoma as, due to its rarity and in spite of detailed immunohistochemical investigations, its exact nosology is only incompletely understood. METHODS: We used microarray-based analysis of gene expression of tumour cells isolated from a patient with primary manifestation of the lymphoma in the skin and compared it with various other diffuse LBCLs (DLBCLs) as well as a previously published DLBCL classifier. RESULTS: In unsupervised analyses, the tumour cells clustered together with non-germinal centre B-cell (non-GCB) DLBCL samples but were clearly distinct from GCB-DLBCL. Analogous to non-GCB DLBCL, molecular cell-of-origin classification revealed similarity to bone-marrow derived plasma cells. CONCLUSIONS: The IVLBCL of this patient showed molecular similarity to non-GCB DLBCL. Due to the prognostic and increasingly also therapeutic relevance of molecular subtyping in DLBCL, this method, in addition to immunohistochemistry, should also be considered for the diagnosis of IVLBCL in the future.

Effect of intravenous immunoglobulin administration on erythrocyte and leucocyte parameters.

BACKGROUND: Intravenous immunoglobulins (IVIG) are an attractive therapeutic tool for therapy of toxic epidermal necrolysis and severe forms of certain autoimmune diseases, including dermatomyositis, autoimmune blistering diseases, systemic vasculitis and lupus erythematodes. OBJECTIVES: Prompted by a case of IVIG-associated haemolytic anaemia, the effects of IVIG administrations on haematological parameters in patients with dermatological conditions were investigated. METHODS: Erythrocyte and leucocyte parameters were retrospectively analysed in 16 patients who had received IVIG at doses from 1 to 3 g/kg bodyweight (n = 35 cycles). The influence of IVIG on leucocyte survival was determined in vitro. RESULTS: Decreased absolute erythrocyte numbers, haemoglobin and haematocrit levels and a case of haemolytic anaemia were linked to transfusion of high-, but not low-dose IVIG. In contrast, leucopenia post-IVIG occurred in the vast majority of the recipients, unrelated to the administered IVIG amounts. In vitro investigations revealed a dose-dependent impairment of cell survival by IVIG in the neutrophil and monocyte, but not in the lymphocyte subpopulations. In several IVIG preparations, substantial amounts of blood group anti-A/anti-B antibodies were detected which could have accounted for the observed changes in the haematological parameters in our study cohort. CONCLUSIONS: IVIG products should be administered strictly according to indications. Commercially available IVIG products can contain blood group-specific antibodies that may induce haemolysis in some recipients. Monitoring of blood counts during applied IVIG therapy, especially when high doses are administered, is recommended.

Rapid point-of-care detection of SARS-CoV-2 infection in exhaled breath using ion mobility spectrometry: a pilot study.

BACKGROUND: An effective testing strategy is essential for pandemic control of the novel Coronavirus disease 2019 (COVID-19) caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Breath gas analysis can expand the available toolbox for diagnostic tests by using a rapid, cost-beneficial, high-throughput point-of-care test. We conducted a bi-center clinical pilot study in Germany to evaluate breath gas analysis using multi-capillary column ion mobility spectrometry (MCC-IMS) to detect SARS-CoV-2 infection. METHODS: Between September 23, 2020, and June 11, 2021, breath gas measurements were performed on 380 patients (SARS-CoV-2 real-time polymerase chain reaction (PCR) positive: 186; PCR negative: 194) presenting to the emergency department (ED) with respiratory symptoms. RESULTS: Breath gas analysis using MCC-IMS identified 110 peaks; 54 showed statistically significant differences in peak intensity between the SARS-CoV-2 PCR-negative and PCR-positive groups. A decision tree analysis classification resulted in a sensitivity of 83% and specificity of 86%, but limited robustness to dataset changes. Modest values for the sensitivity (74%) and specificity (52%) were obtained using linear discriminant analysis. A systematic search for peaks led to a sensitivity of 77% and specificity of 67%; however, validation by transferability to other data is questionable. CONCLUSIONS: Despite identifying several peaks by MCC-IMS with significant differences in peak intensity between PCR-negative and PCR-positive samples, finding a classification system that allows reliable differentiation between the two groups proved to be difficult. However, with some modifications to the setup, breath gas analysis using MCC-IMS may be a useful diagnostic toolbox for SARS-CoV-2 infection. TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov on September 21, 2020 (NCT04556318; Study-ID: HC-N-H-2004).

MR safety: fast T1 thermometry of the RF-induced heating of medical devices.

Determining the MR compatibility of medical implants and devices is becoming increasingly relevant. In most cases, the heating of conductive implants due to radiefrequency (RF) excitation pulses is measured by fluoroptic temperature sensors in relevant tests for approval. Another common method to determine these heating effects is MR thermometry using the proton resonance frequency. This method gives good results in homogeneous phantoms. However in many cases, technical shortcomings such as susceptibility artifacts prohibit exact proton resonance frequency thermometry near medical implants. Therefore, this work aimed at developing a fast T1-based method which allows controlled MR-related heating of a medical implant while simultaneously quantifying the spatial and temporal temperature distribution. To this end, an inversion recovery snapshot Fast Low-Angle Shot (FLASH) sequence was modified with additional off-resonant heating pulses. With an accelerated imaging method and a sliding-window technique, every 7.6 s a new temperature map could be generated with a spatial in-plane resolution of 2 mm. The temperature deviation from calculated temperature values to reference fluoroptic probe was found to be smaller than 1 K.

PET/MRI-evaluated brown adipose tissue activity may be related to dietary MUFA and omega-6 fatty acids intake.

An investigation of new ways to activate brown adipose tissue (BAT) is highly valuable, as it is a possible tool for obesity prevention and treatment. The aim of our study was to evaluate the relationships between dietary intake and BAT activity. The study group comprised 28 healthy non-smoking males aged 21-42 years. All volunteers underwent a physical examination and 75-g OGTT and completed 3-day food intake diaries to evaluate macronutrients and fatty acid intake. Body composition measurements were assessed using DXA scanning. An FDG-18 PET/MR was performed to visualize BAT activity. Brown adipose tissue was detected in 18 subjects (67% normal-weight individuals and 33% overweight/obese). The presence of BAT corresponded with a lower visceral adipose tissue (VAT) content (p = 0.04, after adjustment for age, daily kcal intake, and DXA Lean mass). We noted significantly lower omega-6 fatty acids (p = 0.03) and MUFA (p = 0.02) intake in subjects with detected BAT activity after adjustment for age, daily average kcal intake, and DXA Lean mass, whereas omega-3 fatty acids intake was comparable between the two groups. BAT presence was positively associated with the concentration of serum IL-6 (p = 0.01) during cold exposure. Our results show that BAT activity may be related to daily omega-6 fatty acids intake.

Automated serial sectioning applied to 3D paper structure analysis.

A better understanding of paper properties requires a detailed knowledge about the spatial arrangement of its constituent materials in its structure. This paper presents a novel approach for the analysis of the three-dimensional paper structure at the fibre level. A technique combining a rotary microtome and an optical microscopy was developed allowing serial sectioning of hundreds of cuts. The microscope is fixed on a moveable stage and mounted in front of a microtome. Repeatedly, thin slices are cut off an embedded paper sample and the cut block surface is scanned in a fully automated process. The prototype built is able to digitize paper samples with a size of more than 1 cm(2) at a possible three-dimensional resolution below 1 µm. Advanced computer vision methods are applied to extract relevant information from the digitized samples. Currently, the most important applications are the analysis of pigment coating layers on the paper surfaces and the analysis of fibre transverse morphology. Besides the analysis of paper structures, this technique is also suited for the spatial analysis of other materials, if the structural features are accessible with light optical microscopy.

Endometrial effects of exemestane compared to tamoxifen within the Tamoxifen Exemestane Adjuvant Multicenter (TEAM) trial: results of a prospective gynecological ultrasound substudy.

OBJECTIVES: This study prospectively assessed the effects of exemestane and tamoxifen on the endometrium in patients receiving adjuvant treatment for postmenopausal hormone receptor-positive breast cancer within the Tamoxifen Exemestane Adjuvant Multicenter (TEAM) trial. METHODS: Patients were randomized to receive tamoxifen or exemestane. In a prespecified trial subprotocol, patients underwent transvaginal ultrasound to assess endometrial thickness at baseline and during a 1- to 3-year treatment period. RESULTS: Among 143 evaluable patients, there were no cases of endometrial thickness >10 mm with exemestane, vs. 11 cases with tamoxifen (p < 0.0003). There was a significant difference between the treatment groups regarding time to endometrial thickness >10mm, in favour of exemestane (p < 0.0001). Time to endometrial thickness > 5 mm was significantly longer for exemestane than for tamoxifen (p < 0.0001). Median time to endometrial thickness > 5 mm or censoring was 583 days in the exemestane group versus 315 days in the tamoxifen group. There were also significantly fewer incidences of endometrial thickness > 5 mm at month 6 and month 12 with exemestane compared to tamoxifen (tamoxifen: 6% and 2%; exemestane: 29% and 39%, respectively). After 12 months, mean increases in endometrial thickness from baseline were 2.64 mm and 6.0mm in the exemestane and tamoxifen groups, respectively (p < 0.0006). Moreover, 17 histologically confirmed endometrial changes were observed in the tamoxifen group, vs. one in the exemestane group. CONCLUSIONS: Exemestane was associated with significantly less endometrial thickening than tamoxifen during adjuvant endocrine therapy for postmenopausal hormone receptor-positive breast cancer.

Crystallization of ApoA1 and ApoE4 nanolipoprotein particles and initial XFEL-based structural studies.

Nanolipoprotein particles (NLPs), also called "nanodiscs", are discoidal particles with a patch of lipid bilayer corralled by apolipoproteins. NLPs have long been of interest due to both their utility as membrane-model systems into which membrane proteins can be inserted and solubilized and their physiological role in lipid and cholesterol transport via HDL and LDL maturation, which are important for human health. Serial femtosecond crystallography (SFX) at X-ray free electron lasers (XFELs) is a powerful approach for structural biology of membrane proteins, which are traditionally difficult to crystallize as large single crystals capable of producing high-quality diffraction suitable for structure determination. To facilitate understanding of the specific role of two apolipoprotein/lipid complexes, ApoA1 and ApoE4, in lipid binding and HDL/LDL particle maturation dynamics and develop new SFX methods involving NLP membrane protein encapsulation, we have prepared and crystallized homogeneous populations of ApoA1 and ApoE4 NLPs. Crystallization of empty NLPs yields semi-ordered objects that appear crystalline and give highly anisotropic and diffuse X-ray diffraction, similar in characteristics to fiber diffraction. Several unit cell parameters were approximately determined for both NLPs from these measurements. Thus, low-background, sample conservative methods of delivery are critical. Here we implemented a fixed target sample delivery scheme utilizing the Roadrunner fast-scanning system and ultra-thin polymer/graphene support films, providing a low-volume, low-background approach to membrane protein SFX. This study represents initial steps in obtaining structural information for ApoA1 and ApoE4 NLPs and developing this system as a supporting scaffold for future structural studies of membrane proteins crystalized in a native lipid environment.

Measurement of apparent cell radii using a multiple wave vector diffusion experiment.

It had been previously shown that an idealized version of the two-wave-vector extension of the NMR pulsed-field-gradient spin echo diffusion experiment can be used to determine the apparent radius of geometries with restricted diffusion. In the present work, the feasibility of the experiment was demonstrated in an NMR imaging experiment, in which the apparent radius of axons in white matter tissue was determined. Moreover, numerical simulations have been carried out to determine the reliability of the results. For small diffusion times, the radius is systematically underestimated. Larger gradient area, finite length gradient pulses, and a statistical distribution of radii within a voxel all have a minor influence on the estimated radius.

Helical repeat and linking number of surface-wrapped DNA.

The geometric properties of duplex DNA are systematically altered when the DNA is wrapped on a protein surface. The linking number of surface-wrapped closed circular DNA is the sum of two integers: the winding number, phi, a function of the helical repeat; and the surface linking number, SLk, a newly defined geometric constant that accounts for the effects of surface geometry on the twist and writhe of DNA. Changes in the helical repeat, h, and in the winding number can be deduced solely from surface geometry and superhelix density, sigma. This treatment relates the theoretically important properties twist and writhe to the more experimentally accessible quantities phi, h, SLk, and sigma. The analysis is applied to three biologically important cases: interwinding of DNA in a plectonemic superhelix, catenated DNA, and minichromosomes.

Binding of cis- and trans-dichlorodiammineplatinum(II) to DNA: evidence for unwinding and shortening of the double helix.

The antitumor drug cis-dichlorodiammineplatinum(II) (cis-DDP) and the inactive trans isomer bind and produce cooperative changes in closed and nicked circular duplex DNA's. Covalent binding of both platinum complexes to the closed circular DNA alters the degree of supercoiling, presumably by disrupting and unwinding the double helix. Electron micrographs show the platinated DNA's to be shortened by up to 50 percent of their original length. At similar ratios of bound platinum per nucleotide, the electrophoretic mobilities of the DNA's in gels containing the dye ethidium bromide are the same for both isomers. The only detectable difference in the binding of the two platinum isomers is an increase in the electrophoretic mobility in nondye gels of closed circular DNA having small amounts of bound cis-DDP that is not apparent for the trans complex.

Stereochemical requirements for intercalation of platinum complexes into double-stranded DNA's.

The complexes 1,10-phenanthrolineethylenediamineplatinum(II) and 2,2'-bipyridineethylenediamineplatinum(II) have a planar, aromatic ligand system that facilitates intercalation, as shown by their ability to unwind closed circular duplex DNA. Nonbonded steric interactions can rotate the pryidine ligands out of the coordination plane in bis(pyridine)ethylenediamineplatinum(II), thus preventing intercalation. Fiber x-ray diffraction patterns of the two metallointeracalators indicate that the binding is governed by the neighbor exclusion principle.

Torsional rigidity of positively and negatively supercoiled DNA.

Time-correlated single-photon counting of intercalated ethidium bromide was used to measure the torsion constants of positively supercoiled, relaxed, and negatively supercoiled pBR322 DNA, which range in superhelix density from +0.042 to -0.123. DNA behaves as coupled, nonlinear torsional pendulums under superhelical stress, and the anharmonic term in the Hamiltonian is approximately 15 percent for root-mean-square fluctuations in twist at room temperature. At the level of secondary structure, positively supercoiled DNA is significantly more flexible than negatively supercoiled DNA. These results exclude certain models that account for differential binding affinity of proteins to positively and negatively supercoiled DNA.

Closed circular DNA as a probe for protein-induced structural changes.

Biological systems are replete with examples of DNA formed into a closed loop structure, either alone or in close association with proteins. Such closed circular DNA molecules are subject to a topological constraint that modifies, often in a major way, the structure and reactivity of the DNA. The topological constraint also permits closed circular DNAs to be used as analytical tools to learn about the structure of DNA-protein complexes.

[Magnetic resonance imaging and active cardiac implants]. / Magnetresonanztomographie und aktive kardiale Implantate.

The combination of magnetic resonance imaging (MRI) and active cardiac implants, such as pacemakers and implantable cardioverter defibrillators (ICD) has been a challenge for electrophysiologists and imaging for many years. Diagnostic and therapeutic possibilities on the one hand and technical hazards on the other hand highlight the need for improvements and algorithms that enable a safe approach to these challenges. The advent of so-called MRI conditional implants provides safe procedures for at least some of the patients with an implant and the need for MRI. Recently published data encourage clinicians not to completely excluded an imaging modality as promising as MRI in clinically urgent cases in the presence of conventional implants. The interdisciplinary consensus paper of the German Society of Cardiology and the German Society of Radiology provides recommendations for these situations. This review article discusses these recommendations and provides an overview of the most recent publications with a focus on the long-term course of device parameters.

A novel, non-invasive, online-monitoring, versatile and easy plant-based probe for measuring leaf water status.

A high-precision pressure probe is described which allows non-invasive online-monitoring of the water relations of intact leaves. Real-time recording of the leaf water status occurred by data transfer to an Internet server. The leaf patch clamp pressure probe measures the attenuated pressure, P(p), of a leaf patch in response to a constant clamp pressure, P(clamp). P(p) is sensed by a miniaturized silicone pressure sensor integrated into the device. The magnitude of P(p) is dictated by the transfer function of the leaf, T(f), which is a function of leaf patch volume and ultimately of cell turgor pressure, P(c), as shown theoretically. The power function T(f)=f(P(c)) theoretically derived was experimentally confirmed by concomitant P(p) and P(c) measurements on intact leaflets of the liana Tetrastigma voinierianum under greenhouse conditions. Simultaneous P(p) recordings on leaflets up to 10 m height above ground demonstrated that changes in T(f) induced by P(c) changes due to changes of microclimate and/or of the irrigation regime were sensitively reflected in corresponding changes of P(p). Analysis of the data show that transpirational water loss during the morning hours was associated with a transient rise in turgor pressure gradients within the leaflets. Subsequent recovery of turgescence during the afternoon was much faster than the preceding transpiration-induced water loss if the plants were well irrigated. Our data show the enormous potential of the leaf patch clamp pressure probe for leaf water studies including unravelling of the hydraulic communication between neighbouring leaves and over long distances within tall plants (trees).

Frequency autocorrelation function of stochastically fluctuating fields caused by specific magnetic field inhomogeneities.

Signal formation in NMR is due to incoherent dephasing of nuclear spins. Of particular practical importance is the situation of nuclear spins undergoing independent stochastic motion in inhomogeneous local magnetic fields, e.g., created by magnetized objects. Since it was demonstrated recently that the frequency correlation function of nuclear spins can be measured directly, a theoretical analysis of such functions is of interest. Here, we provide a numerically exact analysis of that correlation function for the inhomogeneous fields around two particular geometries: cylinders and spheres. The functional form exhibits three regimes: after an initial transient, there is an algebraic regime with a t(-d/2) time dependence (d being the space dimension), followed by an exponential cutoff due to microscopic system size effects. The main parameter controlling the range of the individual regimes is the volume fraction of the magnetized objects. In addition to our numerical analysis, which is based on eigenfunction expansions, we provide analytical results and approximations based on the generalized moment expansion.

Scaling laws for transverse relaxation times.

Simple scaling laws are useful tools in understanding the effect of changing parameters in MRI experiments. In this paper the general scaling behavior of the transverse relaxation times is discussed. We consider the dephasing of spins diffusing around a field inhomogeneity inside a voxel. The strong collision approximation is used to describe the diffusion process. The obtained scaling laws are valid over the whole dynamic range from motional narrowing to static dephasing. The dependence of the relaxation times on the external magnetic field, diffusion coefficients of the surrounding medium, and the characteristic scale of the field inhomogeneity is analyzed. For illustration the generally valid scaling laws are applied to the special case of a capillary, usually used as a model of the myocardial BOLD effect.

Local frequency density of states around field inhomogeneities in magnetic resonance imaging: effects of diffusion.

A method describing NMR-signal formation in inhomogeneous tissue is presented which covers all diffusion regimes. For this purpose, the frequency distribution inside the voxel is described. Generalizing the results of the well-known static dephasing regime, we derive a formalism to describe the frequency distribution that is valid over the whole dynamic range. The expressions obtained are in agreement with the results obtained from Kubos line-shape theory. To examine the diffusion effects, we utilize a strong collision approximation, which replaces the original diffusion process by a simpler stochastic dynamics. We provide a generally valid relation between the frequency distribution and the local Larmor frequency inside the voxel. To demonstrate the formalism we give analytical expressions for the frequency distribution and the free induction decay in the case of cylindrical and spherical magnetic inhomogeneities. For experimental verification, we performed measurements using a single-voxel spectroscopy method. The data obtained for the frequency distribution, as well as the magnetization decay, are in good agreement with the analytic results, although experiments were limited by magnetic field gradients caused by an imperfect shim and low signal-to-noise ratio.