Electro-Freezing of Supercooled Water Is Induced by Hydrated Al3+ and Mg2+ Ions: Experimental and Theoretical Studies.

This work reports that the octahedral hydrated Al3+ and Mg2+ ions operate within electrolytic cells as kosmotropic (long-range order-making) "ice makers" of supercooled water (SCW). 10-5 M solutions of hydrated Al3+ and Mg2+ ions each trigger, near the cathode (-20 ± 5 V), electro-freezing of SCW at -4 °C. The hydrated Al3+ ions do so with 100% efficiency, whereas the Mg2+ ions induce icing with 40% efficiency. In contrast, hydrated Na+ ions, under the same experimental conditions, do not induce icing differently than pure water. As such, our study shows that the role played by Al3+ and Mg2+ ions in water electro-freezing is impacted by two synchronous effects: (1) a geometric effect due to the octahedral packing of the coordinated water molecules around the metallic ions, and (2) the degree of polarization which these two ions induce and thereby acidify the coordinated water molecules, which in turn imparts them with an ice-like structure. Long-duration molecular dynamics (MD) simulations of the Al3+ and Mg2+ indeed reveal the formation of "ice-like" hexagons in the vicinity of these ions. Furthermore, the MD shows that these hexagons and the electric fields of the coordinate water molecules give rise to ultimate icing. As such, the MD simulations provide a rational explanation for the order-making properties of these ions during electro-freezing.

Chemical Nature of Heterogeneous Electrofreezing of Supercooled Water Revealed on Polar (Pyroelectric) Surfaces.

ConspectusThe ability to control the icing temperature of supercooled water (SCW) is of supreme importance in subfields of pure and applied sciences. The ice freezing of SCW can be influenced heterogeneously by electric effects, a process known as electrofreezing. This effect was first discovered during the 19th century; however, its mechanism is still under debate. In this Account we demonstrate, by capitalizing on the properties of polar crystals, that heterogeneous electrofreezing of SCW is a chemical process influenced by an electric field and specific ions. Polar crystals possess a net dipole moment. In addition, they are pyroelectric, displaying short-lived surface charges at their hemihedral faces at the two poles of the crystals as a result of temperature changes. Accordingly, during cooling or heating, an electric field is created, which is negated by the attraction of compensating charges from the environment. This process had an impact in the following experiments. The icing temperatures of SCW within crevices of polar crystals are higher in comparison to icing temperatures within crevices of nonpolar analogs. The role played by the electric effect was extricated from other effects by the performance of icing experiments on the surfaces of pyroelectric quasi-amorphous SrTiO3. During those studies it was found that on positively charged surfaces the icing temperature of SCW is elevated, whereas on negatively charged surfaces it is reduced. Following investigations discovered that the icing temperature of SCW is impacted by an ionic current created within a hydrated layer on top of hydrophilic faces residing parallel to the polar axes of the crystals. In the absence of such current on analogous hydrophobic surfaces, the pyroelectric effect does not influence the icing temperature of SCW. Those results implied that electrofreezing of SCW is a process influenced by specific compensating ions attracted by the pyroelectric field from the aqueous solution. When freezing experiments are performed in an open atmosphere, bicarbonate and hydronium ions, created by the dissolution of atmospheric CO2 in water, influence the icing temperature. The bicarbonate ions, when attracted by positively charged pyroelectric surfaces, elevate the icing temperature, whereas their counterparts, hydronium ions, when attracted by the negatively charged surfaces reduce the icing temperature. Molecular dynamic simulations suggested that bicarbonate ions, concentrated within the near positively charged interfacial layer, self-assemble with water molecules to create stabilized slightly distorted "ice-like" hexagonal assemblies which mimic the hexagons of the crystals of ice. This occurs by replacing, within those ice-like hexagons, two hydrogen bonds of water by C-O bonds of the HCO3- ion. On the basis of these simulations, it was predicted and experimentally confirmed that other trigonal planar ions such as NO3-, guanidinium+, and the quasi-hexagonal biguanidinium+ ion elevate the icing temperature. These ions were coined as "ice makers". Other ions including hydronium, Cl-, and SO4-2 interfere with the formation of ice-like assemblies and operate as "ice breakers". The higher icing temperatures induced within the crevices of the hydrophobic polar crystals in comparison to the nonpolar analogs can be attributed to the proton ordering of the water molecules. In contrast, the icing temperatures on related hydrophilic surfaces are influenced both by compensating charges and by proton ordering.

Identification of Cancer Cells in the Human Body by Anti-Telomerase Peptide Antibody: Towards the Isolation of Circulating Tumor Cells.

Early detection of tumor cells by identifying universal Tumor Associated Antigens (TAA) can drastically change our diagnostic, theranostic and therapeutic possibilities to cure cancer. Human Telomerase Reverse Transcriptase (hTERT), a hallmark of cancer, could act as an optimal TAA candidate. Here we report about the development of a monoclonal antibody against hTERT peptide (α-hTERT mAb) presented on the surface of cancer cells and its possible applications as a pan-cancer marker. Liquid biopsies, an innovative tool in precision oncology, comprising the noninvasive analysis of circulating tumor-derived material to counteract limitations associated with tissue biopsies. Within the tumor circulome, the US Food and Drug Administration already approved the use of circulating tumor cells (CTCs) as valid liquid biopsies. However, currently CTCs are being trapped using antibodies against specific cancer types, with anti EpCAM as the most common antibody, directed mainly against solid tumors. Moreover, the precision medicine approach is based on specific cancer type directed antibodies. Our novel mAb against the hTERT 16-mer peptide, corresponding to amino acids 611-626, is capable of detecting various types of cancer cells both in vitro and ex vivo from tumors of patients with either hematological or solid tumors. This antibody does not bind to normal lymphocytes cells. Cleavage of our antibody to F(ab')2 fragments increased its binding specificity to the tested cancer cells. Future studies may point to the use of this antibody in the procedure of capturing CTCs.

Engineering of Pyroelectric Crystals Decoupled from Piezoelectricity as Illustrated by Doped α-Glycine.

Design of pyroelectric crystals decoupled from piezoelectricity is not only a topic of scientific curiosity but also demonstrates effects in principle that have the potential to be technologically advantageous. Here we report a new method for the design of such materials. Thus, the co-doping of centrosymmetric crystals with tailor-made guest molecules, as illustrated by the doping of α-glycine with different amino acids (Threonine, Alanine and Serine). The polarization of those crystals displays two distinct contributions, one arising from the difference in dipole moments between guest and host and the other from the displacement of host molecules from their symmetry-related positions. These contributions exhibit different temperature dependences and response to mechanical deformation. Thus, providing a proof of concept for the ability to design pyroelectric materials with reduced piezoelectric coefficient (d22 ) to a minimal value, below the resolution limit of the method (<0.005 pm/V).

Leukemic Phase of Histiocytic Sarcoma of the Digestive System: A Rare Manifestation of a Rare Disease.

Histiocytic sarcoma (HS) is a rare, malignant, and aggressive subtype of histiocytosis. We present an unusual case of aggressive HS presenting in the gastrointestinal tract and gallbladder that progressed after several lines of chemotherapy with a leukemic phase. We review the clinical, pathological, and molecular characteristics of HS in this case and review the literature on HS involving the digestive system as well as on overt leukemic phase of this disease. HS is often diagnosed at an advanced stage, and mortality is high. We discuss the therapeutic approach to patients with HS. We highlight the role of overexpression and somatic alterations in the RAF-MEK-ERK pathway in the pathogenesis of HS and discuss potential targeted approaches to treat these rare tumors.

Heterogeneous Electrofreezing Triggered by CO2 on Pyroelectric Crystals: Qualitatively Different Icing on Hydrophilic and Hydrophobic Surfaces.

By performing icing experiments on hydrophilic and hydrophobic surfaces of pyroelectric amino acids and on the x-cut faces of LiTaO3 , we discovered that the effect of electrofreezing of super cooled water is triggered by ions of carbonic acid. During the cooling of the hydrophilic pyroelectric crystals, a continuous water layer is created between the charged hemihedral faces, as confirmed by impedance measurements. As a result, a current of carbonic acid ions, produced by dissolved environmental CO2 , flows through the wetted layer towards the hemihedral faces and elevates the icing temperature. This proposed mechanism is based on the following: (i) on hydrophilic surfaces, water with dissolved CO2 (pH 4) freezes at higher temperatures than pure water of pH 7. (ii) In the absence of the ionic current, achieved by linking the two hemihedral faces of hydrophilic crystals by a conductive paint, water of the two pH levels freeze at the same temperature. (iii) On hydrophobic crystals with similar pyroelectric coefficients, where there is no continuous wetted layer, no electrofreezing effect is observed.

Heterogeneous Electrofreezing of Super-Cooled Water on Surfaces of Pyroelectric Crystals is Triggered by Trigonal Planar Ions.

Electrofreezing experiments of super-cooled water (SCW) with different ions, performed directly on the charged hemihedral faces of pyroelectric LiTaO3 and AgI crystals, in the presence and in the absence of pyroelectric charge are reported. It is demonstrated that bicarbonate (HCO3 - ) ions elevate the icing temperature near the positively charged faces. In contrast, the hydronium (H3 O+ ) slightly reduces the icing temperature. Molecular dynamics simulations suggest that the hydrated trigonal planar HCO3 - ions self-assemble with water molecules near the surface of the AgI crystal as clusters of slightly different configuration from those of the ice-like hexagons. These clusters, however, have a tendency to serve as embryonic nuclei for ice crystallization. Consequently, we predicted and experimentally confirmed that the trigonal planar ions of NO3 - and guanidinium (Gdm+ ), at appropriate concentrations, elevate the icing temperature near the positive and negative charged surfaces, respectively. On the other hand, the Cl- and SO4 2- ions of different configurations reduce the icing temperature.

Polar Imperfections in Amino Acid Crystals: Design, Structure, and Emerging Functionalities.

Crystals are physical arrays delineated by polar surfaces and often contain imperfections of a polar nature. Understanding the structure of such defects on the molecular level is of topical importance since they strongly affect the macroscopic properties of materials. Moreover, polar imperfections in crystals can be created intentionally and specifically designed by doping nonpolar crystals with "tailor-made" additives as dopants, since their incorporation generally takes place in a polar mode. Insertion of dopants also induces a polar deformation of neighboring host molecules, resulting in the creation of polar domains within the crystals. The contribution of the distorted host molecules to the polarity of such domains should be substantial, particularly in crystals composed of molecules with large dipole moments, such as the zwitterionic amino acids, which possess dipole moments as high as ∼14 D. Polar materials are pyroelectric, i.e., they generate surface charge as a result of temperature change. With the application of recent very sensitive instruments for measuring electric currents, coupled with theoretical computations, it has become possible to determine the structure of polar imperfections, including surfaces, at a molecular level. The detection of pyroelectricity requires attachment of electrodes, which might induce various artifacts and modify the surface of the crystal. Therefore, a new method for contactless pyroelectric measurement using X-ray photoelectron spectroscopy was developed and compared to the traditional periodic temperature change technique. Here we describe the molecular-level determination of the structure of imperfections of different natures in molecular crystals and how they affect the macroscopic properties of the crystals, with the following specific examples: (i) Experimental support for the nonclassical crystal growth mechanism as provided by the detection of pyroelectricity from near-surface solvated polar layers present at different faces of nonpolar amino acid crystals. (ii) Enantiomeric disorder in dl-alanine crystals disclosed by detection of anomalously strong pyroelectricity along their nonpolar directions. The presence of such disorder, which is not revealed by accurate diffraction techniques, explains the riddle of their needlelike morphology. (iii) The design of mixed polar crystals of l-asparagine·H2O/l-aspartic acid with controlled degrees of polarity, as determined by pyroelectricity and X-ray diffraction, and their use in mechanistic studies of electrofreezing of supercooled water. (iv) Pyroelectricity coupled with dispersion-corrected density functional theory calculations and molecular dynamics simulations as an analytical method for the molecular-level determination of the structure of polar domains created by doping of α-glycine crystals with different l-amino acids at concentrations below 0.5%. (v) Selective insertion of minute amounts of alcohols within the bulk of α-glycine crystals, elucidating their role as inducers of the metastable ß-glycine polymorph. In conclusion, the various examples demonstrate that although these imperfections are present in minute amounts, they can be detected by the sensitive pyroelectric measurement, and by combining them with theoretical computations one can elucidate their diverse emerging functionalities.

Achiral amino acid glycine acts as an origin of homochirality in asymmetric autocatalysis.

Chiral crystals of the only achiral proteinogenic α-amino acid, glycine induced the asymmetric autocatalysis with amplification of enantiomeric excess (ee). The P31 crystals of γ-glycine, which display positive Cotton effect (CD) at around 215 nm, mediate the asymmetric autocatalysis to yield (R)-pyrimidyl alkanol with high ee. In contrast, the enantiomorphic P32 crystals, which display negative Cotton effect, afford (S)-alkanol after the significant amplification of ee by asymmetric autocatalysis.

The Effects of Proteasome Inhibitors on Telomerase Activity and Regulation in Multiple Myeloma Cells.

The importance of telomerase, the enzyme that maintains telomere length, has been reported in many malignancies in general and in multiple myeloma (MM) in particular. Proteasome inhibitors are clinically used to combat effectively MM. Since the mechanism of action of proteasome inhibitors has not been fully described we sought to clarify its potential effect on telomerase activity (TA) in MM cells. Previously we showed that the first generation proteasome inhibitor bortezomib (Brt) inhibits TA in MM cells by both transcriptional and post-translational mechanisms and has a potential clinical significance. In the current study we focused around the anti- telomerase activity of the new generation of proteasome inhibitors, epoxomicin (EP) and MG-132 in order to clarify whether telomerase inhibition represents a class effect. We have exposed MM cell lines, ARP-1, CAG, RPMI 8226 and U266 to EP or MG and the following parameters were assessed: viability; TA, hTERT expression, the binding of hTERT (human telomerase reverse transcriptase) transcription factors and post-translational modifications. Epoxomicin and MG-132 differentially downregulated the proliferation and TA in all MM cell lines. The downregulation of TA and the expression of hTERT were faster in CAG than in ARP-1 cells. Epoxomicin was more potent than MG-132 and therefore further mechanistic studies were performed using this compound. The inhibition of TA was mainly transcriptionally regulated. The binding of three positive regulator transcription factors: SP1, c-Myc and NF-κB to the hTERT promoter was decreased by EP in CAG cells as well as their total cellular expression. In ARP-1 cells the SP1 and c-MYC binding and protein levels were similarly affected by EP while NF-κB was not affected. Interestingly, the transcription factor WT-1 (Wilms' tumor-1) exhibited an increased binding to the hTERT promoter while its total cellular amount remained unchanged. Our results combined with our previous study of bortezomib define telomerase as a general target for proteasome inhibitors. The inhibitory effect of TA is exerted by several regulatory levels, transcriptional and post translational. SP1, C-Myc and NF-κB were involved in mediating these effects. A novel finding of this study is the role of WT-1 in the regulation of telomerase which appears as a negative regulator of hTERT expression. The results of this study may contribute to future development of telomerase inhibition as a therapeutic modality in MM.

[THE EFFECT OF INFECTIOUS AND AUTOIMMUNE DISEASES ON PROCOAGULANT ACTIVITY OF FIBRINOGEN-LIKE PROTEIN 2 IN THE PERIPHERAL BLOOD].

AIMS: In this article we address the effect of bacterial or viral infections as well as autoimmune diseases on FGL2 activity in the blood. BACKGROUND: Fibrinogen-like protein 2 (FGL2) is a novel prothrombinase capable of initiating thrombin generation independent of the classical coagulation pathway. FGL2 is involved in immune-coagulation response. Considering the tight relationship between coagulation and cancer, FGL2 had been suggested to be utilized as a potential biomarker for cancer. Recently, we have shown that FGL2 activity is increased in blood of B-cell lymphoma patients and decreased during remission. However, it is unclear whether FGL2 activity is simultaneously affected by the presence of conditions other than cancer. METHODS: FGL2 procoagulant activity levels were examined in peripheral blood cell samples of 93 patients with clinical diagnosis of various bacterial or viral infections or autoimmune diseases, and 39 healthy controls. Activity was determined according to clotting time measurements. Clinical and demographic data was collected. RESULTS: FGL2 activity in peripheral blood samples of healthy individuals and patients was rather similar. Moreover, no significant correlation was detected between measured FGL2 activity and clinical or demographic data of the patients. The range of activities was rather broad, indicating high variance (up to 2.5-fold from average) in the basal activity levels in the population. CONCLUSIONS: The presence of infectious/autoimmune diseases does not significantly alter FGL2 activity in the peripheral blood. DISCUSSION: While FGL2 activity in the blood is affected by malignancies such as lymphomas, the presence of inflammatory/infectious diseases does not significantly influence basal FGL2 activity. The broad range of FGL2 activities in tested samples indicates that FGL2 is a better marker for follow up implications than diagnostic screening.

Agranulocytosis Associated with Waldenström Macroglobulinemia.

Currently, there are only 2 case reports of Waldenström macroglobulinemia (WM) associated with severe neutropenia. This is a case report of a woman with a past medical history of WM who presented with neutropenic fever. The patient's febrile neutropenia resolved after RCD chemotherapy (cyclophosphamide 750 mg/m2, dexamethasone 20 mg, and rituximab 375 mg/m2). Fourteen days after administration, the neutrophil level had started to rise and normalized after 6 days. To the best of our knowledge, this is the 3rd reported case of agranulocytosis due to WM.

Solvent-Induced Crystal Polymorphism as Studied by Pyroelectric Measurements and Impedance Spectroscopy: Alcohols as Tailor-Made Inhibitors of α-Glycine.

Metastable polymorphs commonly emerge when the formation of the stable analogues is inhibited by using different solvents or auxiliaries. Herein, we report that when glycine is grown in aqueous solutions in the presence of low concentrations of different co-solvents, only alcohols and acetone, unlike water and acetic acid, are selectively incorporated in minute amounts within the bulk of the α-polymorph. These findings demonstrate that although water binds more strongly to the growing face of the crystal, alcohols and acetone are exclusively incorporated, and thus serve as efficient inhibitors of this polymorph, leading to the precipitation of the ß-form. These solvents then create polar domains detectable by pyroelectric measurements and impedance spectroscopy. These results suggest that in the control of crystal polymorphism with co-solvents, one should consider also the different desolvation rates in addition to the energy of binding to the growing faces of the crystal.

The Contribution of Pyroelectricity of AgI Crystals to Ice Nucleation.

The pyroelectricity of AgI crystals strongly affects the icing temperature of super-cooled water, as disentangled from that of epitaxy. This deduction was achieved by the design of polar crystalline ceramic pellets of AgI, with experimentally determined sense of polarity. These pellets are suitable for measuring both their pyroelectric properties as well as the icing temperature of super-cooled water, separately on each of the expressed Ag+ and I- hemihedral surfaces. The positive pyroelectric charge at the silver-enriched side elevates the icing temperature, whereas the negative charge at the iodide side decreases that temperature. Moreover, the effect of pyroelectric charge remains dominant despite the presence of contaminants on both the silver and the iodide-enriched surfaces. Consequently an electrochemical process for ice nucleation is suggested, which might be of relevance for understanding the role played by electric charges in heterogeneous icing processes in general.

Characterisation of blood-derived exosomal hTERT mRNA secretion in cancer patients: a potential pan-cancer marker.

BACKGROUND: Telomerase (human telomerase reverse transcriptase (hTERT)) is considered a hallmark of cancer. The aim of our study was to evaluate the feasibility of the detection of hTERT transcripts in serum as a 'pan-cancer' diagnostic method. METHODS: Human telomerase reverse transcriptase mRNA levels were determined in serum and serum-derived exosomes from 133 patients with different malignancies and 45 healthy controls. In four patients hTERT mRNA levels were measured in different clinical stages. RESULTS: Human telomerase reverse transcriptase transcript was absent in all controls and was variably detected in 67.5% of patients with all cancer types. A correlation between hTERT transcript levels and the clinical course was found in several cases. CONCLUSIONS: Human telomerase reverse transcriptase mRNA levels may reflect the tumour burden and the clinical status of the patient. In patients with detectable levels, this assay may potentially serve as a diagnostic and follow-up 'pan-cancer' marker. Owing to the large variety of patients and small sample size in each diagnosis, the statistical power is limited and will be explored further in larger groups.

[EXOSOMES AS MEDIATORS OF INTERCELLULAR COMMUNICATION: THE CANCER AND TELOMERASE CONNECTION].

INTRODUCTION: Exosomes, nano-vesicles secreted from all types of cells in the human body, function as inter-cell communicators. This role of exosomes is fulfilled by their specific content, dependent on the origin of donor cells from which they are secreted. Exosomes contain a plethora of nucleic acids (DNA, RNA and micro RNA), proteins and lipids. These molecules are packed in the donor cells into the exosomes which are subsequently secreted and transferred through various body fluids into the target cells which may be located far from the donor cells. Recently, the issue of exosome research has been widely expanded and data has been accumulated regarding the relevance and involvement of exosomes in cancer. Exosomes play a role in the process of malignant transformation, in avoiding the surveillance of the immune system, the expansion of the tumor and its establishment in the cancer microenvironment. In addition, exosomes promote the process of metastasis formation. Among other subjects, exosomal research focuses around the characterization of the content of cancer-derived exosomes in order to identify markers that can be used for diagnosis and prognosis of cancer patients. Telomerase, a unique reverse transcriptase, has been widely shown to be crucial for the process of malignant transformation and the perpetuation of the malignant clone. In the current review, we describe the importance of exosomes to the various themes of cancer and their potential use as diagnostic and prognostic markers as well as their therapeutic potential. In addition, the results and implications of our study with regards to the secretion of telomerase transcript into exosomes derived from cancer cells will be discussed.

Nonclassical Crystal Growth as Explanation for the Riddle of Polarity in Centrosymmetric Glycine Crystals.

The riddle of anomalous polar behavior of the centrosymmetric crystal of α-glycine is resolved by the discovery of a polar, several hundred nanometer thick hydrated layer, created at the {010} faces during crystal growth. This layer was detected by two independent pyroelectric analytical methods: (i) periodic temperature change technique (Chynoweth) at ambient conditions and (ii) contactless X-ray photoelectron spectroscopy under ultrahigh vacuum. The total polarization of the surface layer is extremely large, yielding ≈1 µC·cm-2, and is preserved in ultrahigh vacuum, but disappears upon heating to 100 °C. Molecular dynamics simulations corroborate the formation of polar hydrated layers at the sub-microsecond time scale, however with a thickness of only several nanometers, not several hundred. This inconsistency might be reconciled by invoking a three-step nonclassical crystal growth mechanism comprising (i) docking of clusters from the supersaturated solution onto the evolving crystal, (ii) surface recognition and polar induction, and (iii) annealing and dehydration, followed by site-selective recrystallization.

Can flow cytometry of bone marrow aspirate predict outcome of patients with diffuse large B cell lymphoma? A retrospective single centre study.

Bone marrow (BM) trephine biopsy is a part of routine staging of patients with newly diagnosed diffuse large B cell lymphoma (DLBCL). The significance of lymphoid monoclonal population on flow cytometry (FC) of the BM aspirate in the presence of negative BM histology has not been clarified. In this study, we assessed the clinical role of positive FC in predicting outcome of patients with DLBCL and a negative BM histology. We retrospectively analysed 101 patients diagnosed with DLBCL at a single institution between years 1994-2003. Three groups of patients were compared: patients with histologic involvement of the BM (BM+), patients with no histologic involvement of the BM but with positive FC (BM-FC+) and patients with neither histologic or FC evidence of BM involvement (BM-FC-). The BM+ group included 13 patients (13%). The BM-FC+ group 16 patients (16%), and the BM-FC-included 72 patients (71%). Median age of the cohort was 67 years. Disease stage and International Prognostic Index score were significantly higher in the BM+ and BM-FC+ groups compared with the BM-FC- group. Median overall survival (OS) for the BM-FC-, BM-FC+ and BM + groups were 4.6, 2.2 and 0.9 years, respectively. Median progression free survival (PFS) for the BM-FC-, BM-FC+ and BM+ groups were 3.2, 1.4 and 0.6 years, respectively (p=0.01 for both analysis). In multivariable Cox regression models adjusting for age, sex, stage and International Prognostic Index, there was no significant differences in OS or PFS between the BM-FC+ and BM-FC- groups. In conclusion, positive FC in the setting of negative BM histology at diagnosis did not significantly affect OS or PFS.