Theory-based cryopreservation mode of mesenchymal stromal cell spheroids.

Cryopreservation of spheroids requires development of new improved methods. The plasma membranes permeability coefficients for water and cryoprotectants determine time characteristics of mass transfer through the cell membranes, and therefore the optimal modes of cells cryopreservation. Here we proposed an approach to cryopreservation of multicellular spheroids which considers their generalized characteristics as analogues of the membranes' permeability coefficients of the individual cells. We have determined such integral characteristics of spheroids from mesenchymal stromal cells (MSCs) as osmotically inactive volume; permeability coefficients for water and Me2SO molecules and the activation energy of their penetration. Based on these characteristics, we calculated the osmotic behavior of multicellular spheroids under cooling conditions to select the optimal cooling rate. We also determined the optimal cooling rate of spheroids using the probabilistic model developed based on the two-factor theory of cryodamage. From the calculation it follows that the optimal cooling rate of the MSC-based spheroids is 0.75°Ð¡/min. To verify the obtained theoretical estimates, we conducted experiments on freezing MSC-based spheroids under different modes. The obtained results of primary viability screening indicate that freezing at a constant linear cooling rate of 0.75-1.0°Ð¡/min gives a good result. Theoretical prediction of the spheroid osmotic behavior during cooling provided the basis for experimental verification of varying the temperature to which slow cooling should be carried out before immersion in liquid nitrogen. Slow freezing of spheroids to -40 °C followed by immersion in liquid nitrogen was shown to preserve cells better than slow freezing to -80 °C. Obtained data allow more effective use of MSC-based spheroids in drug screening and regenerative medicine.

Hypothermic organ perfusion in the 2020s: mixing the benefits of low temperatures and dynamic flow outside the body.

The cold chain supply of donor organs for transplantation has been an integral part of the delivery of transplant clinical services over the past five decades. Within the technologies used for this, hypothermic machine perfusion (HMP) was a concept, which was attractive to maintain organs under optimal conditions outside the body, and many early research studies on HMP were reported. However, it took the arrival of important new concepts to ensure that HMP was logistically feasible and valuable from an organ physiology perspective within the clinical pathways. This review provides details of the current status of HMP across the range of organs transplanted in the clinic, and discusses what new areas might benefit from applying HMP in coming years. In conclusion, HMP is now being used more frequently for clinical organ preservation in a variety of settings. As new therapies such as cell or gene therapy become more common, HMP will continue to play an important facilitator role for optimising organs in the donor pathway. doi.org/10.54680/fr22510110112.

Special temperatures in frustrated ferromagnets.

The description and detection of unconventional magnetic states, such as spin liquids, is a recurring topic in condensed matter physics. While much of the efforts have traditionally been directed at geometrically frustrated antiferromagnets, recent studies reveal that systems featuring competing antiferromagnetic and ferromagnetic interactions are also promising candidate materials. We find that this competition leads to the notion of special temperatures, analogous to those of gases, at which the competing interactions balance, and the system is quasi-ideal. Although induced by weak perturbing interactions, these special temperatures are surprisingly high and constitute an accessible experimental diagnostic of eventual order or spin-liquid properties. The well characterised Hamiltonian and extended low-temperature susceptibility measurement of the canonical frustrated ferromagnet Dy2Ti2O7 enables us to formulate both a phenomenological and microscopic theory of special temperatures for magnets. Other members of this class of magnets include kapellasite Cu3Zn(OH)6Cl2 and the spinel GeCo2O4.

Magnetisation process in the rare earth tetraborides, NdB4 and HoB4.

A field-induced magnetisation process in the frustrated antiferromagnets is often much richer compared to the materials without competing interactions. The applied field tends to stabilise unusual spin configurations which frequently results in the appearance of magnetisation plateaux. Here we report a study into the field-induced magnetisation of the two frustrated rare earth tetraborides, HoB4 and NdB4. NdB4 shows a fractional magnetisation plateau occurring at M/M sat ≈ [Formula: see text] before saturating in a field of 33 kOe. On cooling down to 0.5 K the temperature dependent susceptibility of NdB4 shows an unconventional transition where the system returns to the zero field antiferromagnetic state from a higher-temperature ferrimagnetic state. We are able to reconstruct the magnetic phase diagram of NdB4 from the magnetisation, susceptibility and resistivity measurements for both H [Formula: see text] c and H ⊥ c. For HoB4, the most interesting behaviour is found at the lowest temperature of 0.5 K, where the field dependent magnetisation demonstrates a new fractional [Formula: see text]-magnetisation plateau. Further insight into the relations between the exchange interactions and single ion effects is gained through high-field magnetisation measurements in both HoB4 and NdB4.

Order by Quenched Disorder in the Model Triangular Antiferromagnet RbFe(MoO_{4})_{2}.

We observe a disappearance of the 1/3 magnetization plateau and a striking change of the magnetic configuration under a moderate doping of the model triangular antiferromagnet RbFe(MoO_{4})_{2}. The reason is an effective lifting of degeneracy of mean-field ground states by a random potential of impurities, which compensates, in the low-temperature limit, the fluctuation contribution to free energy. These results provide a direct experimental confirmation of the fluctuation origin of the ground state in a real frustrated system. The change of the ground state to a least collinear configuration reveals an effective positive biquadratic exchange provided by the structural disorder. On heating, doped samples regain the structure of a pure compound, thus allowing for an investigation of the remarkable competition between thermal and structural disorder.

Role of matrix metalloproteinase 9 and its tissue inhibitor 1 in development and prognosis of diabetic retinopathy.

The article presents the results of investigation of violations in the proteolysis system in patients with type 2 diabetes and diabetic retinopathy (DR). We studied the levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-I (TIMP-1) in the blood and in the intraocularfluid ofpatients with type 2 diabetes depending upon the stage of DR. We have established that the level of MMP-9 and TIMP- in the blood and in the intraocular fluid increased in patients with type 2 diabetes without signs of DR and with any stage of DR compared to the levels of these parameters in patients without diabetes. Increasing the levels of MMP-9 and TIMP-J took place with increasing of DR severity and reached its maximum levels at the proliferative stage of DR. It was found that the levels of MMP-9 in the intraocular fluid and type 2 diabetes duration affected theprobability of developing diabetic macular edema. At the level of MMP-9 105 ng/ml and 2 diabetes duration 10 years, the probability of developing macular edema was 100%. As a result of the construction ofpredictive models it was found that the level of MMP-9 in the intraocular fluid, stage of DR at the beginning of observation and type 2 diabetes duration had influence on the probability of the development ofproliferative DR over 4 years offollow-up. If the level of MMP-9 100 ng/ml, type 2 diabetes duration 10 years and absence of DR at the beginning of observation were observed the probability of developing proliferative DR would compose 85.9%.

[ROLE OF ULTRASONIC CAVITATION IN COMPLEX TREATMENT OF SUPPURATIVE-NECROTIC COMPLICATIONS OF DIABETIC FOOT SYNDROME].

The microbial landscape of wounds with suppurative-necrotic complications in diabetic foot syndrome (DFS) was investigated. Capabilities by inhibiting the formation of bacterial biofilms using ultrasonic cavitation (USC) were determined. In 32 patients over the purulent necrotic complications DFS USC applied using the apparatus "Sonoca-180" company Soring (Germany), 20 patients performed a basic therapy. Qualitative and quantitative composition of microflora were determined by the results of microbiological investigations using parallel transmission electron microscopy dynamics with USC. In patients with DFS noted the formation of bacterial biofilms that contained clusters of microorganisms in a polysaccharide matrix and were fixed to the wound surface. In the microbial landscape of wounds dominated gram-negative microorganisms. Application of USC contributed to the rapid cleanse wounds.

Recombinant N-Domain of Pregnancy-Specific Glycoprotein from E. coli Cells: Analysis of the Spectrum of Polyclonal Antibodies.

We studied antibody spectrum in antisera to IgG-like recombinant N-domain of pregnancyspecific glycoprotein-1 (rPSG-N) from E. coli cells. In three experimental series, the fraction of IgG antibodies from anti-rPSG-N sera was immobilized on 3 immunoadsorbents: by polymerization with glutaraldehyde, on glutaraldehyde activated biogel P-300, and on commercial CNBr-activated 4B sepharose. Retroplacental serum was incubated with immobilized antibodies to rPSG1-N, protein was eluted and tested in the precipitation test in standard test systems with PSG1, IgG, and human serum albumin. Three proteins were eluted from all 3 immunoadsorbents: PSG1, IgG, and human serum albumin, which demonstrated the spectrum of antibodies to 3 proteins present also in natural serum PSG1 complex. The proportions of PSG1 and IgG obtained in these experiments were similar to those in natural serum PSG1 complex, while the level of human serum albumin was significantly higher in natural PSG1 complex. Thus, we failed to obtain PSG1 monoprotein free from IgG and human serum albumin. Antigenic mosaicism of the polypeptide chain of IgG-like rPSG1-N relative to the antigenic polyvalence of the complex of three proteins present in bioactive preparation of natural serum PSG1 was discussed.

[BREAST-CONSERVING SURGERY AFTER NEOADJUVANT THERAPY FOR BREAST CANCER].

In the randomized phase 2 study there was evaluated the efficacy of neoadjuvant endocrine treatment (anastrozole, exemestane) in comparison with chemotherapy (doxorubicin plus paclitaxel). Preoperative endocrine therapy was well tolerated. There was a trend towards higher overall rates of objective response and breast conserving surgery (BCS) among patients with tumors expressing high levels of ER (luminal A) in endocrine therapy group compared with chemotherapy group (43% vs 24%; p = 0,054). In HER2-positive breast cancer patients the addition of trastuzumab to neoadjuvant chemotherapy improved the overall and pathological complete response. Trastuzumab made possible an increasing number of breast conserving surgery (23% vs 13%; p = 0,022). No patient treated with trastuzumab and with chemotherapy had a local recurrence after BCS.

Dispersionless Spin Waves and Underlying Field-Induced Magnetic Order in Gadolinium Gallium Garnet.

We report the results of neutron diffraction and inelastic neutron scattering on a powder sample of Gd_{3}Ga_{5}O_{12} at high magnetic fields. Analysis of the diffraction data shows that in high fields (B≳1.8 T) the spins are not fully aligned, but are canted slightly as a result of the dipolar interaction. The magnetic phase for fields ≲1.8 T is characterized by antiferromagnetic peaks at (210) and an incommensurate wave vector. The dominant contribution to inelastic scattering at large momentum transfers is from a band of almost dispersionless excitations. We show that these correspond to the spin waves localized on ten site rings, expected on the basis of nearest neighbor exchange interaction, and that the spectrum at high fields B≳1.8 T is well described by a spin wave theory.

Transforming growth factor-beta signaling network regulates plasticity and lineage commitment of lung cancer cells.

Identification of target cells in lung tumorigenesis and characterization of the signals that control their behavior is an important step toward improving early cancer diagnosis and predicting tumor behavior. We identified a population of cells in the adult lung that bear the EpCAM+CD104+CD49f+CD44+CD24loSCA1+ phenotype and can be clonally expanded in culture, consistent with the properties of early progenitor cells. We show that these cells, rather than being restricted to one tumor type, can give rise to several different types of cancer, including adenocarcinoma and squamous cell carcinoma. We further demonstrate that these cells can be converted from one cancer type to the other, and this plasticity is determined by their responsiveness to transforming growth factor (TGF)-beta signaling. Our data establish a mechanistic link between TGF-beta signaling and SOX2 expression, and identify the TGF-beta/SMAD/SOX2 signaling network as a key regulator of lineage commitment and differentiation of lung cancer cells.

ΔNp63 regulates select routes of reprogramming via multiple mechanisms.

Somatic cells can be converted into induced pluripotent stem cells (iPSCs) by forced expression of various combinations of transcription factors, but the molecular mechanisms of reprogramming are poorly understood. Specifically, evidence that the reprogramming process can take many distinct routes only begins to emerge. It is definitively established that p53 deficiency greatly enhances reprogramming, revealing p53's barrier function for induced pluripotency, but the role of its homologs p63 and p73 are unknown. Here we report that in stark contrast to p53, p73 has no role in reprogramming. However, p63 is an enabling (rather than a barrier) factor for Oct4, Sox2 and Klf4 (OSK) and Oct4 and Sox2 (OS), but not for Oct4 and Klf4 (OK) reprogramming of mouse embryonic fibroblasts. Specifically, p63 is essential during reprogramming for maximum efficiency, albeit not for the ability to reprogram per se, and is dispensable for maintaining stability and pluripotency of established iPSC colonies. ΔNp63, but not TAp63, is the principal isoform involved. Loss of p63 can affect reprogramming via several mechanisms such as reduced expression of mesenchymal-epithelial transition and pluripotency genes, hypoproliferation and loss of the most reprogrammable cell populations. During OSK and OS reprogramming, different mechanisms seem to be critical, such as regulation of epithelial and pluripotency genes in OSK reprogramming versus regulation of proliferation in OS reprogramming. Finally, our data reveal three different routes of reprogramming by OSK, OS or OK, based on their differential p63 requirements for iPSC efficiency and pluripotency marker expression. This supports the concept that many distinct routes of reprogramming exist.

Magnetic field-induced ordering in SrDy2O4.

Heat capacity measurements were used to investigate the magnetic ordering processes in single-crystal samples of SrDy2O4 in a magnetic field applied along the [010] and [001] directions. In zero field this compound appears to be magnetically disordered down to at least 0.39 K. A magnetic field applied along the [010] direction induces a very sharp transition at 20 kOe, seen as a strong peak in the heat capacity versus field, C(H) curves, while for H // [001], the magnetization process is accompanied by the development of only broad features in the C(H) curves. The process of field-induced ordering in SrDy2O4 appears to be rather remarkable even in the context of the unusual phase transitions observed in other geometrically frustrated magnetic systems consisting of hexagons and triangles.

[The incidence of postoperative myocardial infarction and the left ventricular function in patients with type 2 diabetes mellitus after recanalization of chronic coronary occlusions].

AIM: To study the effects of intracoronary administration of the ischemic preconditioning (IP) trigger adenosine on the reduced incidence of percutaneous coronary intervention (PCI)-associated myocardial infarction (MI) and left ventricular (LV) systolic and contractile function in patients with type 2 diabetes mellitus (DM) during recanalization of chronic coronary occlusions (CCO). SUBJECTS AND METHODS: The patients were divided into 4 groups: 1) 45 patients without DM who received intracoronary placebo infusion; 2) 51 patients without DM who had 10 mg intracoronary adenosine during PCI; 3) 34 patients with type 2 DM who had intracoronary adenosine during PCI; 4) 37 with type 2 DM who received intracoronary placebo. Troponin I and the MB fraction of creatine phosphokinase were measured an hour before and 18-24 hours and 5 days after PCI. The authors estimated the incidence of PCI-associated MI according to the ESC/ACCF/AHA/WHF (2007) criteria and the time course of changes in LV ejection fraction (EF) and end-systolic volume (ESV) and end-diastolic volume, impaired LV local contractility index (ILVLCI) in 167 patients with CCO 1 day and 1 and 12 months after PCI. RESULTS: There was an improvement in myocardial systolic and contractile function after recanalization and stenting for CCO. The intracoronary adenosine groups showed significantly reduced incidence of PCI-associated MI, increased LV EF, and decreased LV ESV and ILVLCI as compared to the placebo groups. CONCLUSION: The intracoronary injection of the IP trigger adenosine is an effective and safe method to improve LV systolic and contractile function in patients with CCO and type 2 DM.

Communication: electronic band gaps of semiconducting zig-zag carbon nanotubes from many-body perturbation theory calculations.

Electronic band gaps for optically allowed transitions are calculated for a series of semiconducting single-walled zig-zag carbon nanotubes of increasing diameter within the many-body perturbation theory GW method. The dependence of the evaluated gaps with respect to tube diameters is then compared with those found from previous experimental data for optical gaps combined with theoretical estimations of exciton binding energies. We find that our GW gaps confirm the behavior inferred from experiment. The relationship between the electronic gap and the diameter extrapolated from the GW values is also in excellent agreement with a direct measurement recently performed through scanning tunneling spectroscopy.

Two-factor reprogramming of somatic cells to pluripotent stem cells reveals partial functional redundancy of Sox2 and Klf4.

Ectopic expression of defined sets of transcription factors in somatic cells enables them to adopt the qualities of pluripotency. Mouse embryonic fibroblasts (MEFs) are the classic target cell used to elucidate the core principles of nuclear reprogramming. However, their phenotypic and functional heterogeneity represents a major hurdle for mechanistic studies aimed at defining the molecular nature of cellular plasticity. We show that reducing the complexity of MEFs by flow cytometry allows the isolation of discrete cell subpopulations that can be efficiently reprogrammed to pluripotency with fewer genes. Using these FACS-sorted cells, we performed a systematic side-by-side analysis of the reprogramming efficiency with different two- and three-factor combinations of Oct4, Sox2 and Klf4. We show that introduction of exogenous Oct4 with either Sox2 or Klf4 does not directly convert MEFs to a pluripotent state. Instead, each combination of factors disrupts the normal cellular homeostasis and establishes transient states characterized by the concurrent expression of mixed lineage markers. These cells convert into induced pluripotent stem cells in a stochastic fashion. Our data suggest that there is a partial functional redundancy between Sox2 and Klf4 in the disruption of cellular homeostasis and activation of regulatory networks that define pluripotency.

[Antioxidant system activation in rats with experimental cirrhosis after injection of cryopreserved fetal liver cells].

The possibility to recover the antioxidant system in rats with experimental liver cirrhosis (LC) after allo- and xenotransplantation of cryopreserved fetal liver cells (FLC) was investigated. It was shown that the content of lipid peroxidation products in the blood serum of animals with LC four weeks after FLC transplantation decreased significantly as compared to control group. Such changes were accompanied by a significant increase of catalase (CAT), glutathione reductase (GR), Se-dependent glutathione peroxidase (GP) activity in the liver and total anti-oxidative activity (AOA) of blood. Obtained results demonstrate that the main direction of FLC effects in animals with LC agree with that we observed previously in other experimental models (partial hepatectomy, chronic alcohol poisoning and hypercholesterolemia). In conclusion, cell therapy may be considered as the universal method for correction of disorders in regulation of free-radical processes in various experimental pathologies.

Slow magnetic order-order transition in the spin chain antiferromagnet Ca3Co2O6.

Using powder neutron diffraction, we have discovered an unusual magnetic order-order transition in the Ising spin chain compound Ca3Co2O6. On lowering the temperature, an antiferromagnetic phase with a propagation vector k=(0.5,-0.5,1) emerges from a higher temperature spin density wave structure with k=(0,0,1.01). This transition occurs over an unprecedented time scale of several hours and is never complete.

Titanium pyrochlore magnets: how much can be learned from magnetization measurements?

We report magnetization data for several titanium pyrochlore systems measured down to 0.5 K. The measurements, performed on single crystal samples in fields of up to 7 kOe, have captured the essential elements of the previously reported phase transitions in these compounds and have also revealed additional important features overlooked previously either because of the insufficiently low temperatures used, or due to limitations imposed by polycrystalline samples. For the spin-ice pyrochlores Dy(2)Ti(2)O(7) and Ho(2)Ti(2)O(7), an unusually slow relaxation of the magnetization has been observed in lower fields, while the magnetization process in higher fields is essentially hysteresis-free and does not depend on sample history. For the XY pyrochlore Er(2)Ti(2)O(7), the magnetic susceptibility shows nearly diverging behaviour on approach to a critical field, H(C) = 13.5 kOe, above which the magnetization does not saturate but continues to grow at a significant rate. For the Heisenberg pyrochlore Gd(2)Ti(2)O(7), the magnetic susceptibility shows a pronounced change of slope at both transition temperatures, T(N1) = 1.02 K and T(N2) = 0.74 K, contrary to the earlier reports.

Anomalous n-type electrical behaviour of Pd-contacted CNTFET fabricated on small-diameter nanotube.

A Pd-contacted dopant-free CNTFET with small-diameter (0.57 nm) carbon nanotube showing an anomalous n-type electrical characteristic is reported for the first time. This observed behaviour is attributed to a carbon nanotube work function higher than (or close to) palladium as well as a large hole-to-electron effective mass ratio of approximately 2.5 predicted by hybridization in small-diameter nanotubes. A variation of the conduction type with temperature is also observed and is attributed to an increase of the palladium work function and decrease of the CNT work function with increasing temperature.