Successful Implementation of Combined Treatment Methods for a Rare Recurrence of Waldenstrom Macroglobulinemia With Extramedullary Lesions.

A 67-year-old woman was admitted to the Hematology Department in 2014 with complaints of weakness and a low-grade fever. After conducting various tests, it was confirmed that she had Waldenstrom macroglobulinemia. She underwent several rounds of chemotherapy and maintenance therapy with rituximab, which resulted in a good clinical response. However, in 2019, an abnormal growth in the soft tissues of patient's frontal region was discovered, which was diagnosed as lymphoplasmacytic lymphoma. This later progressed to an intracranial lesion. The patient underwent radiation therapy for both the extramedullary and intracranial growths, which had a positive effect. A year later, she developed a lesion in her lymph nodes and soft tissues of her right leg, which was confirmed to be a recurrence of Waldenstrom disease. She underwent further treatment and is currently in complete remission. This case highlights the rare occurrence of relapse in Waldenstrom disease and the challenges in diagnosing extramedullary lesions. It also demonstrates the success of modern treatment approaches using a combination of therapies.

Divergent and Nucleophile-Assisted Rearrangement in the Construction of Pyrrolo[2,1-b][3]benzazepine and Pyrido[2,1-a]isoquinoline Scaffolds.

Under microwave (MW) irradiation at 150 °C in toluene and in the presence of nucleophiles (DMAP, triphenylphosphine and tetrahydrothiophene) 1-substituted 1-ethynyl-2-vinyldi- and tetrahydroisoquinolines undergo [3,3]-sigmatropic rearrangement providing pyrrolo[2,1-b][3]benzazepines in good yields. The replacement of toluene with acetonitrile directs the rearrangement towards the formation of 7,11b-dihydro-6H-pyrido[2,1-a]isoquinolines.

Life Cycle Assessment of Rare Earth Elements-Free Permanent Magnet Alternatives: Sintered Ferrite and Mn-Al-C.

Permanent magnets are fundamental constituents in key sectors such as energy and transport, but also robotics, automatization, medicine, etc. High-performance magnets are based on rare earth elements (RE), included in the European list of critical raw materials list. The volatility of their market increased the research over the past decade to develop RE-free magnets to fill the large performance/cost gap existing between ferrites and RE-based magnets. The improvement of hard ferrites and Mn-Al-C permanent magnets plays into this important technological role in the near future. The possible substitution advantage was widely discussed in the literature considering both magnetic properties and economic aspects. To evaluate further sustainability aspects, the present paper gives a life cycle assessment quantifying the environmental gain resulting from the production of RE-free magnets based on traditional hexaferrite and Mn-Al-C. The analysis quantified an advantage of both magnets that overcomes the 95% in all the considered impact categories (such as climate change, ozone depletion, human toxicity) compared to RE-based technologies. The benefit also includes the health and safety of working time aspects, proving possible reduction of worker risks by 3-12 times. The results represent the fundamentals for the development of green magnets that are able to significantly contribute to an effective sustainable transition.

Oligomerization and Adjuvant Activity of Peptides Derived from the VirB4-like ATPase of Clostridioides difficile.

In a previous study, we demonstrated that the Clostridioides difficile VirB4-like ATPase forms oligomers in vitro. In the current investigation, to study the observed phenomenon in more detail, we prepared a library of VirB4-derived peptides (delVirB4s) fused to a carrier maltose-binding protein (MBP). Using gel chromatography and polyacrylamide gel electrophoresis, we found a set of overlapping fragments that contribute most significantly to protein aggregation, which were represented as water-soluble oligomers with molecular masses ranging from ~300 kD to several megadaltons. Membrane filtration experiments, sucrose gradient ultracentrifugation, and dynamic light scattering measurements indicated the size of the soluble complex to be 15-100 nm. It was sufficiently stable to withstand treatment with 1 M urea; however, it dissociated in a 6 M urea solution. As shown by the changes in GFP fluorescence and the circular dichroism spectra, the attachment of the delVirB4 peptide significantly altered the structure of the partner MBP. The immunization of mice with the hybrid consisting of the selected VirB4-derived peptide and MBP, GST, or GFP resulted in increased production of specific antibodies compared to the peptide-free carrier proteins, suggesting significant adjuvant activity of the VirB4 fragment. This feature could be useful for the development of new vaccines, especially in the case of "weak" antigens that are unable to elicit a strong immune response by themselves.

Neurite Outgrowth and Gene Expression Profile Correlate with Efficacy of Human Induced Pluripotent Stem Cell-Derived Dopamine Neuron Grafts.

Transplantation of human induced pluripotent stem cell-derived dopaminergic (iPSC-DA) neurons is a promising therapeutic strategy for Parkinson's disease (PD). To assess optimal cell characteristics and reproducibility, we evaluated the efficacy of iPSC-DA neuron precursors from two individuals with sporadic PD by transplantation into a hemiparkinsonian rat model after differentiation for either 18 (d18) or 25 days (d25). We found similar graft size and dopamine (DA) neuron content in both groups, but only the d18 cells resulted in recovery of motor impairments. In contrast, we report that d25 grafts survived equally as well and produced grafts rich in tyrosine hydroxylase-positive neurons, but were incapable of alleviating any motor deficits. We identified the mechanism of action as the extent of neurite outgrowth into the host brain, with d18 grafts supporting significantly more neurite outgrowth than nonfunctional d25 grafts. RNAseq analysis of the cell preparation suggests that graft efficacy may be enhanced by repression of differentiation-associated genes by REST, defining the optimal predifferentiation state for transplantation. This study demonstrates for the first time that DA neuron grafts can survive well in vivo while completely lacking the capacity to induce recovery from motor dysfunction. In contrast to other recent studies, we demonstrate that neurite outgrowth is the key factor determining graft efficacy and our gene expression profiling revealed characteristics of the cells that may predict their efficacy. These data have implication for the generation of DA neuron grafts for clinical application.

Case Report: AL Amyloidosis Severe Restrictive Cardiomyopathy Associated With Multiple Myeloma-Diagnostic Difficulties.

Background: Cardiac AL amyloidosis as a complication of multiple myeloma (MM) is a formidable life-threatening condition. The first-line therapy for both MM and systemic AL amyloidosis is proteasome inhibitors (PIs). Unfortunately, the use of PIs may lead to cardiovascular toxicity development, which requires specific cardio-oncology supervision. Case Report: A 57-year-old woman was admitted to a university hospital with clinical manifestation of progressive chronic heart failure. The patient had hypertension and no history of diabetes mellitus, myocardial infarction (MI), stroke, and arrhythmias. After a series of laboratory and instrumental examination methods, MM complicated by cardiac AL amyloidosis was proved. Upon specific cardio-oncology examination (NT-proBNP 4,274 pg/ml), ECHO showed systolic dysfunction, motion abnormalities in LV basal and middle segments, and a typical depositional myocardium pattern ("luminescence"); cardiac MRI revealed restrictive cardiomyopathy and specific hyperenhancement of the ventricles and atria; 24-h ECG showed QS-pattern in leads V1-V3 and unstable ventricular tachycardia (VT) paroxysms. Cardio-oncology consultation showed baseline cardiovascular risk was very high (≥20%), and cardioprotective therapy [iACE/ARBs, beta-blockers (BB), statins] was administered. The patient underwent VCD (bortezomib; cyclophosphamide; dexamethasone) chemotherapy (CMT) program. By the time of publication, the patient had received four CMT courses with a positive oncohematological and cardiovascular effect. Conclusion: In this clinical case, we described a complication of MM, which was rare according to the severity and manifestation with restrictive cardiomyopathy due to secondary cardiac amyloidosis. The case's features were difficulties in verifying the underlying disease and its own complication, and the complexity of patient management according to modern principles of cardio-oncology.

Maturation Delay of Human GABAergic Neurogenesis in Fragile X Syndrome Pluripotent Stem Cells.

Fragile X Syndrome (FXS), the leading monogenic cause of intellectual disability and autism spectrum disorder, is caused by expansion of a CGG trinucleotide repeat in the 5'-UTR of the Fragile X Mental Retardation-1 (FMR1) gene. Epigenetic silencing of FMR1 results in loss of the Fragile X Mental Retardation Protein (FMRP). Although most studies to date have focused on excitatory neurons, recent evidence suggests that GABAergic inhibitory networks are also affected. To investigate human GABAergic neurogenesis, we established a method to reproducibly derive inhibitory neurons from multiple FXS and control human pluripotent stem cell (hPSC) lines. Electrophysiological analyses suggested that the developing FXS neurons had a delay in the GABA functional switch, a transition in fetal development that converts the GABAA channel's function from depolarization to hyperpolarization, with profound effects on the developing brain. To investigate the cause of this delay, we analyzed 14 400 single-cell transcriptomes from FXS and control cells at 2 stages of GABAergic neurogenesis. While control and FXS cells were similar at the earlier time point, the later-stage FXS cells retained expression of neuroblast proliferation-associated genes and had lower levels of genes associated with action potential regulation, synapses, and mitochondria compared with controls. Our analysis suggests that loss of FMRP prolongs the proliferative stage of progenitors, which may result in more neurons remaining immature during the later stages of neurogenesis. This could have profound implications for homeostatic excitatory-inhibitory circuit development in FXS, and suggests a novel direction for understanding disease mechanisms that may help to guide therapeutic interventions.

VirB4- and VirD4-Like ATPases, Components of a Putative Type 4C Secretion System in Clostridioides difficile.

The type 4 secretion system (T4SS) represents a bacterial nanomachine capable of trans-cell wall transportation of proteins and DNA and has attracted intense interest due to its roles in the pathogenesis of infectious diseases. In the current investigation, we uncovered three distinct gene clusters in Clostridioides difficile strain 630 encoding proteins structurally related to components of the VirB4/D4 type 4C secretion system from Streptococcus suis strain 05ZYH33 and located within sequences of conjugative transposons (CTn). Phylogenic analysis revealed that VirB4- and VirD4-like proteins of the CTn4 locus, on the one hand, and those of the CTn2 and CTn5 loci, on the other hand, fit into separate clades, suggesting specific roles of identified secretion system variants in the physiology of C. difficile. Our further study on VirB4- and VirD4-like products encoded by CTn4 revealed that both proteins possess Mg2+-dependent ATPase activity, form oligomers (most likely hexamers) in aqueous solutions, and rely on potassium but not sodium ions for the highest catalytic rate. VirD4 binds nonspecifically to DNA and RNA. The DNA-binding activity of VirD4 strongly decreased with the W241A variant. Mutations in the nucleotide sequences encoding presumable Walker A and Walker B motifs decreased the stability of the oligomers and significantly but not completely attenuated the enzymatic activity of VirB4. In VirD4, substitutions of amino acid residues in the peptides reminiscent of Walker structural motifs neither attenuated the enzymatic activity of the protein nor influenced the oligomerization state of the ATPase. IMPORTANCE C. difficile is a Gram-positive, anaerobic, spore-forming bacterium that causes life-threatening colitis in humans. Major virulence factors of the microorganism include the toxins TcdA, TcdB, and CDT. However, other bacterial products, including a type 4C secretion system, have been hypothesized to contribute to the pathogenesis of the infection and are considered possible virulence factors of C. difficile. In the current paper, we describe the structural organization of putative T4SS machinery in C. difficile and characterize its VirB4- and VirD4-like components. Our studies, in addition to its significance for basic science, can potentially aid the development of antivirulence drugs suitable for the treatment of C. difficile infection.

Emergency Splenectomy in a Patient with Splenic Marginal Zone Lymphoma, Acute Portal Vein Thrombosis, and Chronic Viral Hepatitis B.

Splenic marginal zone lymphoma (SMZL) is a type of non-Hodgkin's lymphoma (NL) that occurs in 2 out of 100 cases and is more common in women aged >60 years. A sluggish, asymptomatic course of the disease does not exclude transformation into a malignant form that occurs in 25% of patients with SMZL. Another equally important sign of an NL is thrombosis that occurs in 3.6% to 17.1% of the cases. In this report, we present a case of emergency splenectomy in a patient owing to difficulties in the diagnosis of SMZL, rapid onset of acute portal vein thrombosis, and the fulminant enlargement of the spleen accompanied by an increased risk of its rupture. Chronic hepatitis B was likely the trigger for transformation of the disease to an aggressive course. Portal vein thrombosis and the aggressive course of SMZL with rapid enlargement of the spleen and threat of its rupture in the background of viral hepatitis B required emergency splenectomy followed by anticoagulant, antiviral, and antitumor therapy.

Changes in plant collection practices from the 16th to 21st centuries: implications for the use of herbarium specimens in global change research.

BACKGROUND AND AIMS: Herbaria were recently advertised as reliable sources of information regarding historical changes in plant traits and biotic interactions. To justify the use of herbaria in global change research, we asked whether the characteristics of herbarium specimens have changed during the past centuries and whether these changes were due to shifts in plant collection practices. METHODS: We measured nine characteristics from 515 herbarium specimens of common European trees and large shrubs collected from 1558 to 2016. We asked botanists to rank these specimens by their scientific quality, and asked artists to rank these specimens by their beauty. KEY RESULTS: Eight of 11 assessed characteristics of herbarium specimens changed significantly during the study period. The average number of leaves in plant specimens increased 3-fold, whereas the quality of specimen preparation decreased. Leaf size negatively correlated with leaf number in specimens in both among-species and within-species analyses. The proportion of herbarium sheets containing plant reproductive structures peaked in the 1850s. The scientific value of herbarium specimens increased until the 1700s, but then did not change, whereas their aesthetic value showed no systematic trends. CONCLUSIONS: Our findings strongly support the hypothesis that many characteristics of herbarium specimens have changed systematically and substantially from the 16th to 21st centuries due to changes in plant collection and preservation practices. These changes may both create patterns which could be erroneously attributed to environmental changes and obscure historical trends in plant traits. The utmost care ought to be taken to guard against the possibility of misinterpretation of data obtained from herbarium specimens. We recommend that directional changes in characters of herbarium specimens which occurred during the past 150‒200 years, primarily in specimen size and in the presence of reproductive structures, are accounted for when searching for the effects of past environmental changes on plant traits.

Biases in estimation of insect herbivory from herbarium specimens.

Information regarding plant damage by insects in the past is essential to explore impacts of climate change on herbivory. We asked whether insect herbivory measured from herbarium specimens reflects the levels of herbivory occurring in nature at the time of herbarium sampling. We compared herbivory measurements between herbarium specimens collected by botany students and ecological samples collected simultaneously by the authors by a method that minimized unconscious biases, and asked herbarium curators to select one of two plant specimens, which differed in leaf damage, for their collections. Both collectors and curators generally preferred specimens with lesser leaf damage, but the strength of this preference varied among persons. In addition, the differences in measured leaf damage between ecological samples and herbarium specimens varied among plant species and increased with the increase in field herbivory. Consequently, leaf damage in herbarium specimens did not correlate with the actual level of herbivory. We conclude that studies of herbarium specimens produce biased information on past levels of herbivory, because leaf damage measured from herbarium specimens not only underestimates field herbivory, but it is not proportional to the level of damage occurring in nature due to multiple factors that cannot be controlled in data analysis.

Reduced intrinsic excitability of CA1 pyramidal neurons in human immunodeficiency virus (HIV) transgenic rats.

The hippocampus is involved in key neuronal circuits that underlie cognition, memory, and anxiety, and it is increasingly recognized as a vulnerable structure that contributes to the pathogenesis of HIV-associated neurocognitive disorder (HAND). However, the mechanisms responsible for hippocampal dysfunction in neuroHIV remain unknown. The present study used HIV transgenic (Tg) rats and patch-clamp electrophysiological techniques to study the effects of the chronic low-level expression of HIV proteins on hippocampal CA1 pyramidal neurons. The dorsal and ventral areas of the hippocampus are involved in different neurocircuits and thus were evaluated separately. We found a significant decrease in the intrinsic excitability of CA1 neurons in the dorsal hippocampus in HIV Tg rats by comparing neuronal spiking induced by current step injections and by dynamic clamp to simulate neuronal spiking activity. The decrease in excitability in the dorsal hippocampus was accompanied by a higher rate of excitatory postsynaptic currents (EPSCs), whereas CA1 pyramidal neurons in the ventral hippocampus in HIV Tg rats had higher EPSC amplitudes. We also observed a reduction of hyperpolarization-activated nonspecific cationic current (Ih) in both the dorsal and ventral hippocampus. Neurotoxic HIV proteins have been shown to increase neuronal excitation. The lower excitability of CA1 pyramidal neurons that was observed herein may represent maladaptive homeostatic plasticity that seeks to stabilize baseline neuronal firing activity but may disrupt neural network function and contribute to HIV-associated neuropsychological disorders, such as HAND and depression.

Comparison of Biomarker Assays for EGFR: Implications for Precision Medicine in Patients with Glioblastoma.

PURPOSE: Patients with glioblastoma (GBM) have a poor prognosis and are in desperate need of better therapies. As therapeutic decisions are increasingly guided by biomarkers, and EGFR abnormalities are common in GBM, thus representing a potential therapeutic target, we systematically evaluated methods of assessing EGFR amplification by multiple assays. Specifically, we evaluated correlation among fluorescence in situ hybridization (FISH), a standard assay for detecting EGFR amplification, with other methods.Experimental Design: Formalin-fixed, paraffin-embedded tumor samples were used for all assays. EGFR amplification was detected using FISH (N = 206) and whole-exome sequencing (WES, N = 74). EGFR mRNA expression was measured using reverse transcription-polymerase chain reaction (RT-PCR, N = 206) and transcriptome profiling (RNAseq, N = 64). EGFR protein expression was determined by immunohistochemistry (IHC, N = 34). Significant correlations among various methods were determined using Cohen's kappa (κ = 0.61-0.80 defines substantial agreement) or R 2 statistics. RESULTS: EGFR mRNA expression levels by RNA sequencing (RNAseq) and RT-PCR were highly correlated with EGFR amplification assessed by FISH (κ = 0.702). High concordance was also observed when comparing FISH to WES (κ = 0.739). RNA expression was superior to protein expression in delineating EGFR amplification. CONCLUSIONS: Methods for assessing EGFR mRNA expression (RT-PCR, RNAseq) and copy number (WES), but not protein expression (IHC), can be used as surrogates for EGFR amplification (FISH) in GBM. Collectively, our results provide enhanced understanding of available screening options for patients, which may help guide EGFR-targeted therapeutic approaches.

Heat-Resistant Ferroelectric-Polymer Nanocomposite with High Dielectric Constant.

The high dielectric constant ferroelectric-polymer nanocomposite was developed for producing the heat-resistant and chemical stable planar layers. According to the composite coatings formation conditions, the following value ranges of dielectric constant and loss factor were received: 30⁻400 for dielectric constant and 0.04⁻0.1 for loss tangent, accordingly. Unlike of composite components, the obtained composite material is characterized by thermo-stability of electrical parameters up to 250 °C. The dielectric frequency spectra of the composite exhibit two clearly visible peaks in contrast to the spectra of the polymer and ferroelectric ceramics. The developed composite material can be used as a built-in film capacitors material in microelectronic devices.

Diverse reprogramming codes for neuronal identity.

The transcriptional programs that establish neuronal identity evolved to produce the rich diversity of neuronal cell types that arise sequentially during development. Remarkably, transient expression of certain transcription factors can also endow non-neural cells with neuronal properties. The relationship between reprogramming factors and the transcriptional networks that produce neuronal identity and diversity remains largely unknown. Here, from a screen of 598 pairs of transcription factors, we identify 76 pairs of transcription factors that induce mouse fibroblasts to differentiate into cells with neuronal features. By comparing the transcriptomes of these induced neuronal cells (iN cells) with those of endogenous neurons, we define a 'core' cell-autonomous neuronal signature. The iN cells also exhibit diversity; each transcription factor pair produces iN cells with unique transcriptional patterns that can predict their pharmacological responses. By linking distinct transcription factor input 'codes' to defined transcriptional outputs, this study delineates cell-autonomous features of neuronal identity and diversity and expands the reprogramming toolbox to facilitate engineering of induced neurons with desired patterns of gene expression and related functional properties.

Anti-c-Met monoclonal antibody ABT-700 breaks oncogene addiction in tumors with MET amplification.

BACKGROUND: c-Met is the receptor tyrosine kinase for hepatocyte growth factor (HGF) encoded by the MET proto-oncogene. Aberrant activation of c-Met resulting from MET amplification and c-Met overexpression is associated with poor clinical outcome in multiple malignancies underscoring the importance of c-Met signaling in cancer progression. Several c-Met inhibitors have advanced to the clinic; however, the development of inhibitory c-Met-directed therapeutic antibodies has been hampered by inherent agonistic activity. METHOD: We generated and tested a bivalent anti-c-Met monoclonal antibody ABT-700 in vitro for binding potency and antagonistic activity and in vivo for antitumor efficacy in human tumor xenografts. Human cancer cell lines and gastric cancer tissue microarrays were examined for MET amplification by fluorescence in situ hybridization (FISH). RESULTS: ABT-700 exhibits a distinctive ability to block both HGF-independent constitutive c-Met signaling and HGF-dependent activation of c-Met. Cancer cells addicted to the constitutively activated c-Met signaling driven by MET amplification undergo apoptosis upon exposure to ABT-700. ABT-700 induces tumor regression and tumor growth delay in preclinical tumor models of gastric and lung cancers harboring amplified MET. ABT-700 in combination with chemotherapeutics also shows additive antitumor effect. Amplification of MET in human cancer tissues can be identified by FISH. CONCLUSIONS: The preclinical attributes of ABT-700 in blocking c-Met signaling, inducing apoptosis and suppressing tumor growth in cancers with amplified MET provide rationale for examining its potential clinical utility for the treatment of cancers harboring MET amplification.

Proton radiation alters intrinsic and synaptic properties of CA1 pyramidal neurons of the mouse hippocampus.

High-energy protons constitute at least 85% of the fluence of energetic ions in interplanetary space. Although protons are only sparsely ionizing compared to higher atomic mass ions, they nevertheless significantly contribute to the delivered dose received by astronauts that can potentially affect central nervous system function at high fluence, especially during prolonged deep space missions such as to Mars. Here we report on the long-term effects of 1 Gy proton irradiation on electrophysiological properties of CA1 pyramidal neurons in the mouse hippocampus. The hippocampus is a key structure for the formation of long-term episodic memory, for spatial orientation and for information processing in a number of other cognitive tasks. CA1 pyramidal neurons form the last and critical relay point in the trisynaptic circuit of the hippocampal principal neurons through which information is processed before being transferred to other brain areas. Proper functioning of CA1 pyramidal neurons is crucial for hippocampus-dependent tasks. Using the patch-clamp technique to evaluate chronic effects of 1 Gy proton irradiation on CA1 pyramidal neurons, we found that the intrinsic membrane properties of CA1 pyramidal neurons were chronically altered at 3 months postirradiation, resulting in a hyperpolarization of the resting membrane potential (VRMP) and a decrease in input resistance (Rin). These small but significant alterations in intrinsic properties decreased the excitability of CA1 pyramidal neurons, and had a dramatic impact on network function in a computational model of the CA1 microcircuit. We also found that proton-radiation exposure upregulated the persistent Na(+) current (INaP) and increased the rate of miniature excitatory postsynaptic currents (mEPSCs). Both the INaP and the heightened rate of mEPSCs contribute to neuronal depolarization and excitation, and at least in part, could compensate for the reduced excitability resulting from the radiation effects on the VRMP and the Rin. These results show long-term alterations in the intrinsic properties of CA1 pyramidal cells after realistic, low-dose proton irradiation.

(28)silicon radiation impairs neuronal output in CA1 neurons of mouse ventral hippocampus without altering dendritic excitability.

An unavoidable complication of space travel is exposure to radiation consisting of high-energy charged particles (HZE), such as Fe and Si nuclei. HZE radiation can affect neuronal functions at the level of the synapse or neuronal soma without inducing significant neuronal death. Different radiation species impart distinct patterns of radiation damage depending on their track structure, dose rate and fluence. Moreover, structural differences exist along the dorsoventral axis of the hippocampus that may underlie different radiosensitivities within the same neuronal field (e.g., the CA1 pyramidal cell population of the hippocampus). In this study we tested the functional effects of low doses of (28)Si radiation on excitability and synaptic plasticity in hippocampal slices prepared strictly from the ventral hippocampus. We used extracellular electrophysiological techniques to record field excitatory postsynaptic potentials (EPSPs) and population spikes in hippocampal CA1 neurons from C57BL/6J male mice 3 months after exposure to (28)Si radiation (600 MeV/n; 0.25 and 1 Gy, whole body). In irradiated mice we found prominent decrements in population spike amplitudes and reduced maximal neuronal output without changes in dendritic field EPSP. Reduced field EPSP vs. population spike ratios indicate radiation-induced impairment of the EPSP-spike (E-S) coupling. This effect was not associated with significant changes in the magnitude of short- and long-term synaptic plasticity [long-term potentiation (LTP)]. These data confirm that irradiation with (28)Si particles at relatively low doses alters the properties of the hippocampal network, which can limit its connectivity with other brain centers.

An effect of glycoprotein IIb/IIIa inhibitors on the kinetics of red blood cells aggregation.

The reversible aggregation of red blood cells (RBCs) continues to be of the basic science and clinical interest. Recently it has been reported about a specific binding between fibrinogen and unknown erythrocyte glycoprotein receptors. The aim of this study was to investigate whether the red blood cell aggregation (RBCA) include the cell-cell interaction using the membrane receptors that bind such ligands as fibrinogen or fibronectin. To test this hypothesis the RBCs were incubated with monafram - the drug of the monoclonal antibodies against glycoprotein (GP) IIb/IIIa, with the GPIIb-IIIa receptor antagonist tirofiban, epifibatide and with the fibrinogen inhibiting peptide. It has been found that the RBC incubation with monafram resulted in a marked RBCA decrease mainly in persons with high level of aggregation. Another research session has shown that RBC incubation with fibronectin was accompanied by a significant RBCA rise. The monafram addition to red cell incubation medium resulted in a significant RBCA lowering. The cell incubation with tirofiban and epifibatide issued in RBCA decrease. The similar results were obtained when RBCs were incubated with the fibrinogen inhibiting peptide. Although monafram, tirofiban, eptifibatide and the fibrinogen inhibiting peptide were related to fibrinogen function they didn't inhibit RBCA completely. Therefore, under moderate and low red blood cell aggregation the cell binding is probably related to nonspecific mode. It seems evident that the specific and nonspecific modes of red blood cell aggregate formation could co-exist. Additional theoretical and experimental investigations in this area are needed.

Normal and system lupus erythematosus red blood cell interactions studied by double trap optical tweezers: direct measurements of aggregation forces.

Direct measurements of aggregation forces in piconewton range between two red blood cells in pair rouleau are performed under physiological conditions using double trap optical tweezers. Aggregation and disaggregation properties of healthy and pathologic (system lupus erythematosis) blood samples are analyzed. Strong difference in aggregation speed and behavior is revealed using the offered method which is proposed to be a promising tool for SLE monitoring at single cell level.