Carboxymethyl-γ-cyclodextrin, a novel selective relaxant binding agent for the reversal of neuromuscular block induced by aminosteroid neuromuscular blockers: an ex vivo laboratory study.

BACKGROUND: Residual neuromuscular block at the end of surgery may compromise the patient's safety. The risk of airway complications can be minimized through monitoring of neuromuscular function and reversal of neuromuscular block if needed. Effective reversal can be achieved with selective relaxant binding agents, however, sugammadex is the only clinically approved drug in this group. We investigated the concentration-response properties of a novel selective relaxant binding agent, carboxymethyl-γ-cyclodextrin for the reversal of neuromuscular block. We evaluated the hypothesis that it is equally potent for reversing neuromuscular block as sugammadex. METHODS: Phrenic nerve - hemidiaphragm tissue preparations were isolated from male Wistar rats and suspended in a tissue holder allowing electrical stimulation of the nerve and monitoring of muscle contraction force. Concentration-response relationships were constructed for the neuromuscular blocking agents rocuronium, pipecuronium, and vecuronium. The half-effective concentrations of sugammadex and carboxymethyl-γ-cyclodextrin for reversal of neuromuscular block were determined. RESULTS: The half effective concentrations (95% confidence interval, CI) were 7.50 (6.93-8.12) µM for rocuronium, 1.38 (1.33-1.42) µM for pipecuronium, and 3.69 (3.59-3.80) µM for vecuronium. The half effective concentrations (95% CI) of carboxymethyl-γ-cyclodextrin and sugammadex were 35.89 (32.67-39.41) µM and 3.67 (3.43-3.92) µM, respectively, for the reversal of rocuronium-induced block; 10.14 (9.61-10.70) µM and 0.67 (0.62-0.74) µM, respectively, for the reversal of pipecuronium-induced block; and 376.1 (341.9-413.8) µM and 1.45 (1.35-1.56) µM, respectively, for the reversal of vecuronium-induced block. CONCLUSIONS: Carboxymethyl-γ-cyclodextrin is an effective, but less potent agent for reversal of neuromuscular block than sugammadex.

The effect of magnesium on the reversal of rocuronium-induced neuromuscular block with sugammadex: an ex vivo laboratory study.

BACKGROUND: Magnesium dose-dependently potentiates the effect of non-depolarizing neuromuscular blocking agents. We investigated whether the potentiation of rocuronium-induced blockade by magnesium reduces the effect of sugammadex in an ex-vivo environment and how this influences the safety margin of reversal. METHODS: Phrenic nerve - hemidiaphragm tissue preparations were isolated from male Wistar rats. The specimens were suspended in a tissue holder that allowed registering muscle contraction amplitude following electrical stimulation of the nerve. Concentration-response relationships were elucidated for magnesium, as well as for rocuronium and sugammadex. RESULTS: The mean (95% confidence interval [CI]) half effective concentrations (EC50) of rocuronium in the presence of magnesium 1 mM or 1.5 mM were 7.50 µM (6.97-8.07 µM) and 4.25 µM (4.09-4.41 µM), respectively (p < 0.0001). Increasing magnesium from 1 mM to 1.5 mM during reversal of rocuronium-induced block increased the mean (95% CI) EC50 of sugammadex from 3.67 µM (3.43-3.92 µM) to 5.36 µM (5.18-5.53 µM), whereas mean (95% CI) effective concentrations for 95% effect (EC95) were not significantly different at 7.22 µM (6.09-8.54 µM) and 7.61 µM (7.05-8.20 µM), respectively (p = 0.542). When rocuronium-induced block was reversed to a train-of-four (TOF) ratio > 0.9, but with still visible fade, increasing magnesium from 1 mM to 2 mM decreased the TOF ratio to below 0.9. If there was no visible fade after reversal, increasing magnesium concentration did not reduce the TOF ratio. CONCLUSIONS: Magnesium potentiates the neuromuscular effect of rocuronium and shifts the concentration-response curve to the left. Magnesium decreases the safety margin of reversal of rocuronium-induced neuromuscular block with sugammadex.

The hitchhikers guide to cancer stem cell theory: markers, pathways and therapy.

Cancer stem cell (CSC) biology is a rapidly developing field within cancer research. CSCs are postulated to be a unique cell population exclusively capable of infinite self renewal, multilineage differentiation and with ability to evade conventional cytotoxic cancer therapy. These traits distinguish CSCs from their more differentiated counterparts, which possess only limited or no potential for self renewal and tumor initiation. Therefore, CSCs would be the driving motor of malignant growth and therapy resistance. Accordingly, successful cancer treatment would need to eliminate this highly potent group of cells, since even small residual numbers would suffice to recapitulate the disease after therapy. Putative CSCs has been identified in a broad range of human malignancies and several cell surface markers have been associated with their stem cell phenotype. Despite all efforts, a pure CSC population has not been isolated and often in vitro clonogenic and in vivo tumorigenic potential is found in several cell populations with occasionally contradictory surface marker signatures. Here, we give a brief overview of recent advances in CSC theory, including the signaling pathways in CSCs that also appear crucial for stem cells homeostasis in normal tissues. We discuss evidence for the interaction of CSCs with the stromal tumor environment. Finally, we review the emerging potentially effective CSC-targeted treatment strategies and their future role in therapy.

TripleFRET measurements in flow cytometry.

A frequently used method for viewing protein interactions and conformation, Förster (fluorescence) resonance energy transfer (FRET), has traditionally been restricted to two fluorophores. Lately, several methods have been introduced to expand FRET methods to three species. We present a method that allows the determination of FRET efficiency in three-dye systems on a flow cytometer. TripleFRET accurately reproduces energy transfer efficiency values measured in two-dye systems, and it can indicate the presence of trimeric complexes, which is not possible with conventional FRET methods. We also discuss the interpretation of energy transfer values obtained with tripleFRET in relation to spatial distribution of labeled molecules, specifically addressing the limitations of using total energy transfer to determine molecular distance.

The role of SARS-CoV-2 antibody therapy in the treatment of COVID-19 / A SARS-CoV-2-ellenes antitestekkel végzett terápia helye a COVID-19 kezelésében.

Összefoglaló. Az új típusú koronavírus (SARS-CoV-2) okozta fertozés és a COVID-19 elleni küzdelem egyik lehetosége a SARS-CoV-2-ellenes neutralizáló antitestekkel végzett passzív immunizáció. Az utóbbi idoben számos készítmény jutott el a klinikai kipróbálásig. Az alábbiakban áttekintjük ezen készítmények legfobb tulajdonságait és az antitest-terápiával elért klinikai eredményeket. Ezek alapján elsosorban prehospitálisan, az állapotprogresszió szempontjából leginkább veszélyeztetett populációnál alkalmazva, e készítmények jelentosen csökkenthetik az állapotromlás esélyét és a kórházi ellátás igényét, ezáltal javíthatják a kimenetelt, és mérsékelhetik az egészségügyi ellátórendszer terhelését. Orv Hetil. 2021; 162(51): 2030-2039. Summary. Passive immunization is a therapeutic option in the fight against the infection caused by the novel coronavirus (SARS-CoV-2) and COVID-19. Significant advances have been made in the development of SARS-CoV-2 neutralizing antibodies. Here we discuss the antibodies under clinical trial and the published data regarding their clinical efficacy. Based on these, when given to non-hospitalized patients at high risk for disease progression, these antibodies can significantly reduce worsening of the disease and the need for hospitalization. This can improve the outcomes of patients and help reduce the burden on the healthcare system. Orv Hetil. 2021; 162(51): 2030-2039.

Strength in numbers: effects of acceptor abundance on FRET efficiency.

Fluorescence resonance energy transfer (FRET) is a strongly distance-dependent process between a donor and an acceptor molecule, which can be used for sensitive distance measurements and characterization of molecular interactions at the nanometer level. The original mathematical description of this process, however, is only valid for the interaction of one donor with one acceptor. This criterion is not always met, especially in biological systems, where multiple structures can interact simultaneously, often making distance estimations based on transfer efficiency values error-prone. Herein we investigate how the interaction of multiple acceptors and donors influences the transfer efficiency value in an intramolecular cellular FRET system by manipulating the fluorophore/protein ratio of the fluorophore-conjugated antibodies. We show that the labeling ratio of the acceptor has the largest influence on measured transfer efficiency and decreasing or increasing the acceptor labeling ratio can be utilized to manipulate the FRET response of the acceptor-donor pair and therefore is a tool for optimizing sensitivity of FRET measurements.

Organ replacement therapy and life-supporting treatment modalities in critically ill COVID-19 patients / [Emelt szintu szervtámogató és életfenntartó kezelések kritikus állapotú COVID­19-fertozött betegeken]

In critically ill COVID-19 patients, the failure of the cardiorespiratory system can be due to one of the following: (1) cytokine storm, haemophagocytosis ­ septic shock, (2) unmanageable hypoxemia, (3) isolated organ failure or as part of multi-organ failure. Herein we give an overview of the therapeutic options for treating or preventing these disease states. In recent years, CytoSorb-haemoperfusion to remove cytokines has shown promising results in the treatment of septic shock. Inhalational nitric oxide (iNO), inhalational epoprostenol and veno-venous extracorporeal membrane oxygenation (ECMO) are options in severe hypoxemia that is unresponsive to conventional mechanical ventilation. Renal failure is a frequent component of the multi-organ failure usually seen with disease progression and necessitates starting one of the available continuous renal replacement modalities. Orv Hetil. 2020; 161(17): 704­709.

Pharmacological options in treating SASR-CoV-2 infection/COVID-19 / [Farmakoterápiás lehetoségek SARS-CoV-2-fertozés/COVID­19-betegség esetén]

There is currently no proven effective therapy for COVID-19. Here we discuss the drugs most investigated for the treatment of the disease. All the listed therapies are experimental at this stage. However, due to the severe healthcare effects of the pandemic and the potentially fatal outcome of COVID-19 patients treated in the intensive care units, their off-label use should none-the-less be considered. Orv Hetil. 2020; 161(17): 685­688.

Practical aspects of intensive care for critically ill COVID-19 patients requiring respiratory support / [Kritikus állapotú, légzéstámogatást igénylo COVID­19-fertozött beteg ellátásának gyakorlati szempontjai]

In December 2019, a novel outbreak of pneumonia was reported in Wuhan city, China. Initially, the zoonitic infection spread from human to human, causing a pandemic. This viral disease (COVID-19) can appear in a variety of forms, from asymptomatic through the spectrum of mild symptoms to severe respiratory failure, requiring intensive care. Caring for this latter group of patients puts a significant burden on health care. The purpose of this summary is to present the practical aspects of intensive care for patients requiring respiratory support and mechanical ventilation. Orv Hetil. 2020; 161(17): 678­684.

Practical aspects of anesthetic and perioperative care for COVID-19 patients / [A COVID­19-fertozött betegek anesztéziájának és perioperatív ellátásának gyakorlati szempontjai]

Caring for those affected by the coronavirus outbreak of December 2019 imposed a heavy burden on healthcare systems. Not only because some patients require intensive care, but because patients with any form of the disease may need surgical intervention. Managing these cases is a major challenge for anesthesiologists. The purpose of this summary is to present the practical aspects of anesthetic and perioperative care for patients requiring surgical treatment. Orv Hetil. 2020; 161(17): 692­695.

Airway management of coronavirus-infected patients / [Légútbiztosítás koronavírus-fertozött betegekben]

The coronavirus pandemic is a serious challenge for healthcare workers worldwide. The virus is spread through the air by droplets of moisture when people cough or sneeze and it has a very high virulence. Procedures generating airway aerosols are dangerous for every participant of patient care. The serious form of coronavirus infection can cause progressive respiratory failure. The best treatment is early endotracheal intubation and invasive mechanical ventilation. Intubation is an aerosol-generating process and thus carries the risk of contamination. Additionally the airway management of this patient population is usually difficult. The goal of this article is to give a practice-based overview of the peculiarities of airway management in coronavirus-infected patients with special regard to infection control and patient safety considerations. Orv Hetil. 2020; 161(17): 696­703.

Intrahospital resuscitation of COVID-19 patients / [A COVID­19-betegek kórházon belüli újraélesztésének speciális szempontjai]

The coronavirus pandemic is a serious challenge for healthcare workers worldwide. The virus is spread through the air by droplets of moisture when people cough or sneeze and it has a very high virulence. Procedures generating airway aerosols are dangerous for every participant of patient care. Mortality of COVID-19 is above 10%, thus cardiopulmonary resuscitation is an often needed intervention in this patient group. Resuscitation is an aerosol-generating process and thus carries the risk of contamination. The goal of this article is to give a practice-based overview of the specialities of cardiopulmonary resuscitation in coronavirus-infected patients. Orv Hetil. 2020. 161(17): 710­712.

Die hard: are cancer stem cells the Bruce Willises of tumor biology?

In recent years, an exponentially growing number of studies have focused on identifying cancer stem cells (CSC) in human malignancies. The rare CSCs could be crucial in controlling and curing cancer: through asymmetric division CSCs supposedly drive tumor growth and evade therapy with the help of traits shared with normal stem cells such as quiescence, self-renewal ability, and multidrug resistance pump activity. Here, we give a brief overview of techniques used to confirm the stem cell-like behavior of putative CSCs and discuss markers and methods for identifying, isolating, and culturing them. We touch on the limitations of each marker and why the combined use of CSC markers, in vitro and in vivo assays may still fail to identify all relevant CSC populations. Finally, the various experimental findings supporting and contradicting the CSC hypothesis are summarized. The large number of tumor types thus far with a subpopulation of uniquely tumorigenic and therapy resistant cells suggests that despite the unanswered questions and inconsistencies, the CSC hypothesis has a legitimate role to play in tumor biology. At the same time, experimental evidence supporting the established alternative theory of clonal evolution can be found as well. Therefore, a model that describes cancer initiation and progression should combine elements of clonal evolution and CSC theory.

Two-sided fluorescence resonance energy transfer for assessing molecular interactions of up to three distinct species in confocal microscopy.

The role of the expression patterns of proteins involved in oncogenesis can be understood after characterizing their multimolecular interactions. Conventional FRET methods permit the analysis of interaction between two molecular species at the most, which necessitates the introduction of new approaches for studying multicomponent signaling complexes. Flow cytometric as well as microscopic donor (dbFRET) and acceptor (abFRET) photobleaching FRET measurements were performed to determine the association states of ErbB2, beta1-integrin, and CD44 receptors. Based on consecutively applied abFRET and dbFRET methods (two-sided FRET), the relationship of beta1-integrin-ErbB2 heteroassociation to ErbB2 homoassociation and of beta1-integrin-ErbB2 heteroassociation to ErbB2-CD44 heteroassociation was studied by correlating pixel-by-pixel FRET values of the corresponding abFRET and dbFRET images in contour plots. Anticorrelation was observed between beta1-integrin-ErbB2 heteroassociation and ErbB2 homoassociation on trastuzumab sensitive N87 and SK-BR-3 cells, while modest positive correlation was found between beta1-integrin-ErbB2 and ErbB2-CD44 heteroassociation on trastuzumab resistant MKN-7 cells. The FRET efficiency values of beta1-integrin-ErbB2 heteroassociation were markedly higher at the focal adhesion regions on attached cells than those measured by flow cytometry on detached cells. In conclusion, we implemented an experimental set-up termed two-sided FRET for correlating two pairwise interactions of three arbitrarily chosen molecular species. On the basis of our results, we assume that the homoassociation state of ErbB2 is dynamically modulated by its interaction with beta1-integrins.

DNA flow cytometry of human spermatozoa: consistent stoichiometric staining of sperm DNA using a novel decondensation protocol.

Rapid flow cytometric measurement of the frequency of aneuploid human sperms is in increasing demand but development of an exploitable method is hindered by difficulties of stoichiometric staining of sperm DNA. An aggressive decondensation protocol is needed after which cell integrity still remains intact. We used flow cytometry to examine the effect of lithium diiodosalicylate (LIS, chaotropic agent) on fluorescence intensity of propidium iodide-treated human spermatozoa from 10 normozoospermic men. When flow cytometric identification of diploid spermatozoa was achieved, validation was performed after sorting by three-color FISH. In contrast with the extremely variable histograms of nondecondensed sperms, consistent identification of haploid and diploid spermatozoa was possible if samples were decondensed with LIS prior to flow cytometry. A 76-fold enrichment of diploid sperms was observed in the sorted fractions by FISH. A significant correlation was found between the proportion of sorted cells and of diploid sperms by FISH. Application of LIS during the preparation of sperm for flow cytometry appears to ensure the stoichiometric staining of sperm DNA, making quantification of aneuploid sperm percentage possible. To our knowledge this is the first report in terms of separating spermatozoa with confirmedly abnormal chromosomal content. High correlation between the proportion of cells identified as having double DNA content by flow cytometry and diploid sperm by FISH allows rapid calculation of diploidy rate.

Design and evaluation of artificial receptors for the reversal of neuromuscular block.

Applying patient friendly and cost-efficient medications in healthcare will be a real challenge in the 21st century. Sugammadex is a selective, yet expensive agent used for the post-surgical reversal of neuromuscular block since 2008. A wide library of cyclodextrin-based follow-ups, having potentially similar affinity towards target aminosteroid type neuromuscular blocking agents has been established. Almost 20 compounds were assessed with respect to in vitro affinity against three commonly applied drugs. Based on the capillary electrophoretic screening, carboxymethylated and sulfobutylated gamma-cyclodextrin derivatives have the potential to be promising lead molecules for their affinity towards pipecuronium was identical or even superior to Sugammadex. Carboxymethylated gamma-cyclodextrin showed efficient and complete reversal of the pipecuronium induced neuromuscular block in an ex vivo rat diaphragm experiment.

Cellular and serological changes in the peripheral blood of splenectomized and spleen autotransplanted mice.

BACKGROUND: Our department worked out a modified surgical form of spleen autotransplantation earlier, named "spleen apron method" introduced already into the clinical practice. Recently we tested the immunological changes in a group of patients autotransplanted with about 10-15% of their spleen, what was the at least always implantable amount after the severe splenic injuries. In the current work we aimed at measuring some cellular and serological changes in the peripheral blood of splenectomized and spleen autotransplanted inbred mice two and eight months after the operations in order to get more unambiguous results than that we could obtain in our patients with this technique. MATERIALS AND METHODS: We divided 96 two months old Balb/c female mice into eight groups (n = 12/group). The group of controls, sham operated, splenectomized and autotransplanted animals with two and eight months of survival time after the operations. During the autotransplantation we inserted the same amount of spleen, five slices, "chips," about 10-15% of total mass of spleen, into the greater omentum similarly as it was used in the patients. The concentration of serum proteins were measured by laser nephelometry. The lymphocyte subsets were analyzed by flow cytometry. RESULTS: We found that two months after the operations the number of CD 19+ B-cells increased in the splenectomized but decreased in the autotransplanted animals. Eight months after the operations the number of both CD3+ T and CD19+ B lymphocytes decreased both in the splenectomized and autotransplanted animals compared to the controls and sham operated mice. However, the numbers of T and B cells were slightly but not significantly higher in the autotransplanted than in the splenectomized mice. The serum level of IgM was also decreased in the splenectomized and autotransplanted mice at both time points, however, eight months after the operations the concentration of IgM was significantly higher in the autotransplanted group than in the splenectomized animals. CONCLUSION: The effects of autotransplanted "chips" were different at the various ages of the animals. Additionally, they showed some immunological benefit being quantitatively in accordance to the amount of the transplanted spleen. The elevated level of serum IgM what we found in the autotransplanted mice even with this amount of transplanted spleen eight months after the operations, however, might have the potentially greatest importance compared to splenectomy. These experiments can prove that the attempts for autotransplantation may have real perspectives but their efficacy depends on the amount of the successfully transplanted (saved) mass of spleen.

[Comparative investigation of the hematologic and immunologic effects of splenectomy and spleen autotransplantation in mice]. / Lép autotranszplantáció és lépeltávolítás haematologiai és immunologiai hatásainak összehasonlító vizsgálata egerekben.

We have analysed the hematological and immunological effects of the Furka's spleen chip method of autotransplantation in Balb/c mice two and eight months after splenectomy and autotransplantation. Our results showed that the autotransplants had positive effect on the partial restoration of the damaged elements of both cellular and humoral immunity appearing after splenectomy. However, these beneficial effects may have some dependence of time and species.

Potassium channel expression in human CD4+ regulatory and naïve T cells from healthy subjects and multiple sclerosis patients.

The membrane potential of human T cells is regulated by two potassium channels: the voltage-gated K(V)1.3 and the Ca2+-activated K(Ca)3.1. These two channels are essential for efficient antigenic activation and proliferation of T cells and are expressed at different levels in naïve, central memory and effector memory T cells. This provides the opportunity to inhibit the proliferation of the targeted subtype by channel-specific blocking compounds. Regulatory T cells (Tregs) also represent a unique subtype of T cells that perform highly specialized tasks in controlling immune responses, which raises the possibility that they too have a distinctive channel expression pattern. Using whole-cell patch-clamp we tested this hypothesis and determined the ion channel expression of CD4+CD25(hi)CD127(lo) regulatory and CD4+CD25(lo)CD127(hi) naïve T cells from the peripheral blood of healthy volunteers and multiple sclerosis (MS) patients sorted by flow cytometry. We have found that naïve and Treg cells from healthy controls expressed equal numbers of K(V)1.3 channels, while Tregs had a greater membrane surface as assessed by capacitance measurements, and consequentially lower channel density than naïve cells, indicating an "incomplete activation state" of Tregs. In contrast, Tregs from MS patients had fewer K(V)1.3 channels than naïve cells and there was no difference in the membrane capacitance or channel density between the two subtypes of cells. The expression level of K(Ca)3.1 channels was similar in all cell subsets. The observed differences in K(V)1.3 channel expression density may contribute to the varying responses upon antigenic stimulation by these cell types in health and disease.

Distribution of peripheral blood cells in mice after splenectomy or autotransplantation.

Our aim was to compare the distribution changes of peripheral leukocytes and erythrocytes in splenectomized and spleen-autotransplanted BALB/c female mice (n = 96), 2 and 8 months after surgery. In total, there were eight groups of animals: splenectomy, autotransplantation, sham, and untreated controls at both time points. We used the spleen-apron method of Furka et al. (Khirurgiia (Mosk) 1989;9:125-127), inserting five spleen chips into the greater omentum, for autotransplantation. Quantitative and qualitative blood cell counts and the phagocytic activity of cells (stimulated with zymosan) were determined. In splenectomized animals, the number of neutrophils significantly increased 8 months after surgery. The greatest phagocytic activity of neutrophils, however, was observed in autotransplanted animals of the same age. In splenectomized animals, erythrocyte volumes were significantly higher in the second postoperative month, but normalized by the eighth month. In conclusion, spleen autotransplantation has some beneficial effects, including clearing erythrocytes and preserving the phagocytic activity of neutrophils in peripheral blood.