The hEag1 K+ Channel Inhibitor Astemizole Stimulates Ca2+ Deposition in SaOS-2 and MG-63 Osteosarcoma Cultures.

The hEag1 (Kv10.1) K+ channel is normally found in the brain, but it is ectopically expressed in tumor cells, including osteosarcoma. Based on the pivotal role of ion channels in osteogenesis, we tested whether pharmacological modulation of hEag1 may affect osteogenic differentiation of osteosarcoma cell lines. Using molecular biology (RT-PCR), electrophysiology (patch-clamp) and pharmacology (astemizole sensitivity, IC50 = 0.135 µM) we demonstrated that SaOS-2 osteosarcoma cells also express hEag1 channels. SaOS-2 cells also express to KCa1.1 K+ channels as shown by mRNA expression and paxilline sensitivity of the current. The inhibition of hEag1 (2 µM astemizole) or KCa1.1 (1 mM TEA) alone did not induce Ca2+ deposition in SaOS-2 cultures, however, these inhibitors, at identical concentrations, increased Ca2+ deposition evoked by the classical or pathological (inorganic phosphate, Pi) induction pathway without causing cytotoxicity, as reported by three completer assays (LDH release, MTT assay and SRB protein assay). We observed a similar effect of astemizole on Ca2+ deposition in MG-63 osteosarcoma cultures as well. We propose that the increase in the osteogenic stimuli-induced mineral matrix formation of osteosarcoma cell lines by inhibiting hEag1 may be a useful tool to drive terminal differentiation of osteosarcoma.

Mgs1 protein supports genome stability via recognition of G-quadruplex DNA structures.

The integrity of the genetic material is crucial for every organism. One intrinsic attack to genome stability is stalling of the replication fork which can result in DNA breakage. Several factors, such as DNA lesions or the formation of stable secondary structures (eg, G-quadruplexes) can lead to replication fork stalling. G-quadruplexes (G4s) are well-characterized stable secondary DNA structures that can form within specific single-stranded DNA sequence motifs and have been shown to block/pause the replication machinery. In most genomes several helicases have been described to regulate G4 unfolding to preserve genome integrity, however, different experiments raise the hypothesis that processing of G4s during DNA replication is more complex and requires additional, so far unknown, proteins. Here, we show that the Saccharomyces cerevisiae Mgs1 protein robustly binds to G4 structures in vitro and preferentially acts at regions with a strong potential to form G4 structures in vivo. Our results suggest that Mgs1 binds to G4-forming sites and has a role in the maintenance of genome integrity.

Periodic Membrane Potential and Ca2+ Oscillations in T Cells Forming an Immune Synapse.

The immunological synapse (IS) is a specialized contact area formed between a T cell and an antigen presenting cell (APC). Besides molecules directly involved in antigen recognition such as the TCR/CD3 complex, ion channels important in the membrane potential and intracellular free Ca2+ concentration control of T cells are also recruited into the IS. These are the voltage-gated Kv1.3 and Ca2+-activated KCa3.1 K+ channels and the calcium release-activated Ca2+ channel (CRAC). However, the consequence of this recruitment on membrane potential and Ca2+ level control is not known. Here we demonstrate that the membrane potential (MP) of murine T cells conjugated with APCs in an IS shows characteristic oscillations. We found that depolarization of the membrane by current injection or by increased extracellular K+ concentration produced membrane potential oscillations (MPO) significantly more frequently in conjugated T cells than in lone T cells. Furthermore, oscillation of the free intracellular Ca2+ concentration could also be observed more frequently in cells forming an IS than in lone cells. We suggest that in the IS the special arrangement of channels and the constrained space between the interacting cells creates a favorable environment for these oscillations, which may enhance the signaling process leading to T cell activation.

Epstein-Barr virus (HHV-4) inoculation to rabbits by intranasal and oral routes results in subacute and/or persistent infection dissimilar to human disease.

OBJECTIVE: We report the infection of New Zealand white rabbits with Epstein-Barr virus (EBV). METHODS: EBV prepared in B95-8 (producer) cells was inoculated to rabbits by combined intranasal and oral routes. Blood and white blood cell (WBC) samples were taken before infection, then on days 8, 28 and 98 post-infection (p.i.). RESULTS: Administration of either 3 × 10(8) (group A, 11 rabbits) or 1 × 10(9) (group B, 10 rabbits) EBV DNA copies per animal induced subacute and/or persistent infection. The IgG antibodies in plasma were detected by ELISA as well as by immunoblot (IB). The IB bands showed mainly antibodies to the BZRF1/Zta transactivation polypeptide (69.2%), the p54 early protein (53.4%) and to the p23 capsid protein (35.8%). No anti-EBNA1 antibody was detected throughout. Viral DNA could be detected by PCR in WBCs and/or spleen of 7 out of 21 infected rabbits (30%), while 60-80% of them showed serologic response. The transiently present EBV DNA was accompanied by LMP1 antigen. CONCLUSIONS: Rabbits developed persistent EBV infection in the absence of EBNA1 antibodies and by the lack of typical infectious mononucleosis-like syndrome. The absence of EBNA1 antibody may reflect the lack of EBNA1 in B cells of EBV-inoculated rabbits.

Short communication: role of Mycoplasma arginini in mastitis caused by Streptococcus dysgalactiae.

We performed a comparative study on the development of mastitis induced by Mycoplasma arginini or Streptococcus dysgalactiae after challenging the cows. Mycoplasma arginini did not cause any clinical symptoms on its own, resulting in only a transient increase of somatic cell count (SCC; increase ranging from 0.5 × 10(6) to 0.8 × 10(6) cells/mL) and a slight decrease of milk production (10%) for 5 d. In contrast, Strep. dysgalactiae induced more severe clinical signs in animals and SCC increased to 1.60 × 10(6) to 2.11 × 10(6) cells/mL for 10 d. In addition, milk production decreased (22.9 to 27.0%) for 10 d. After 3 mo (2 mo after the first challenge), animals that were challenged previously with M. arginini were rechallenged with Strep. dysgalactiae. Severe clinical mastitis developed, with very high SCC (5.00 × 10(6) to 21.5 × 10(6) cells/mL), and a very significant reduction of milk production (28.6 to 68.7%), which lasted more than 4 wk, was observed. The severe clinical mastitis developed not only in cows inoculated with Strep. dysgalactiae andM. arginini in the same udder quarter but also in cows infected in the quarter previously not challenged with mycoplasma. Cows challenged first with Strep. dysgalactiae and rechallenged with M. arginini 2 mo later developed only slight changes in both SCC and milk production, similar to those when the cows were challenged with M. arginini alone. We conclude that M. arginini infection does not cause remarkable mastitis (characterized by decrease in milk production and increase of SCC) but it significantly predisposes animals to infection with Strep. dysgalactiae, leading to severe clinical mastitis.

Environmental heterogeneity increases the conservation value of small natural features in karst landscapes.

Local biodiversity hotspots are often located within regions where extreme and variable environmental - e.g., climatic and soil - conditions occur. These areas are conservation priorities. Although environmental heterogeneity is recognised as an important determinant of biodiversity, studies focusing on the effects of multiple environmental heterogeneity components in the same ecosystem are scarce. Here we investigate how topography and related microclimatic variables and soil properties may influence the biodiversity and conservation value of karst landscapes. Karst landscapes of the world contain millions of dolines (i.e. bowl- or funnel-shaped depressions) that may function as 'small natural features' with a disproportionately large role in maintaining biodiversity relative to their size. We assessed the diversity of microclimates, soils and vegetation and their relationships in six microhabitats (south-facing slopes, east-facing slopes, west-facing slopes, north-facing slopes and bottoms of dolines, and the adjacent plateau) for nine large dolines in a grassland ecosystem. Although there were remarkable differences among the conservation value of these microhabitats (e.g., representation of different species groups, presence of 'climate relicts'), each microhabitat had an important role in maintaining species that are rare or absent in other microhabitats in the landscape. We found that the studied dolines exhibited highly variable environmental conditions and promoted a high diversity of vegetation types with unique species composition, contributing to the topographic, climatic, soil, vegetation and land cover heterogeneity of karst landscapes. Therefore, our findings highlight that dolines may function as local biodiversity hotspots and have a crucial conservation importance. As dolines are widespread topographic features in many karst landscapes throughout the world, our results could be directly applied to other regions as well. An integrated approach is urgently needed to provide guidelines for landscape management, promoting the retention of the microhabitat diversity of small natural features for species vulnerable to climate change and/or various disturbances.

Successful unrelated umbilical cord blood transplantation in Lesch-Nyhan syndrome.

Lesch-Nyhan syndrome (LNS) is a chronic, progressive neurodevelopmental disorder causing motor and behavioral dysfunction due to decreased synthesis of the enzyme hypoxantine-guanine phosphoribosyltransferase (HPRT). Affected boys have mental retardation, delayed development, extrapyramidal motor disturbances and self-injuring behavior. As hematopoietic stem cell transplantation (HSCT) has been shown to be effective in several neurodevelopmental inborn errors, we hypothesized that it could be favorable in LNS as well. Following a myeloablative conditioning regimen (busulphan 3.2 mg/kg/day for 4 days, cyclophosphamide 60 mg/kg/day for 2 days with ATG Thymoglobin 2.5 mg/kg/day for 4 days) an unrelated umbilical cord blood unit was transfused at the age of 2 years. The graft was a 6/6 HLA-matched at HLA-A, B loci by antigen level, and at DRB1 by allelic level typing. Infused total nucleated cell dose was 3.6 × 10e7 per kilogram body weight. Serum HPRT levels reached normal values by the end of the sixth month post transplant. Slow neurodevelopmental improvement seen during the three-year follow-up and the missing self-injuring behavior can be considered as a proof for the presence of enzyme-competent cells behind the blood-brain barrier.

Co-seeding grasses and forbs supports restoration of species-rich grasslands and improves weed control in ex-arable land.

Sowing is widely used for the restoration of species-rich grasslands but still there are knowledge gaps regarding the most suitable application of different seed mixtures. We tested the effect of seed mixtures application timing on the establishment of sown forbs and weed control. 36 experimental plots with nine sowing treatments were established in an abandoned cropland in Hungary. Grass-seeds, diverse forb seed mixture and the combination of the two were applied: diverse forb mixture was sown simultaneously or 1, 2 or 3 years after grass sowing, in plots sown previously with grass or in empty plots (fallows). All sowing treatments supported the rapid establishment of the sown species in large cover and hampered weed encroachment. Forbs performed better when sown into fallows than in grass-matrix and forbs establishment was worse in older fallows than in younger ones. Grasses expressed a strong priority effect, especially when forbs were sown at least two years later than grasses. We also investigated the relation between seed germinability, weather parameters and establishment success. Germination rate in the greenhouse could not predict the establishment success of forbs in the field and showed great differences between years, hence we recommend sowing target forbs in multiple years.

Vertical distribution of soil seed bank and the ecological importance of deeply buried seeds in alkaline grasslands.

Background: Soil seed banks play a central role in vegetation dynamics and may be an important source of ecological restoration. However, the vast majority of seed bank studies examined only the uppermost soil layers (0-10 cm); hence, our knowledge on the depth distribution of seed bank and the ecological significance of deeply buried seeds is limited. The aim of our study was to examine the fine-scale vertical distribution of soil seed bank to a depth of 80 cm, which is one of the largest studied depth gradients so far. Our model systems were alkaline grasslands in East-Hungary, characterised by harsh environmental conditions, due to Solonetz soil reference group with Vertic horizon. We asked the following questions: (1) How do the seedling density and species richness of soil seed bank change along a vertical gradient and to what depth can germinable seeds be detected? (2) What is the relationship between the depth distribution of the germinable seeds and the species traits? Methods: In each of the five study sites, four soil cores (4 cm diameter) of 80 cm depth were collected with an auger for soil seed bank analysis. Each sample was divided into sixteen 5-cm segments by depth (320 segments in total). Samples were concentrated by washing over sieves and then germinated in an unheated greenhouse. Soil penetration resistance was measured in situ next to each core location (0-80 cm depth, 1-cm resolution). We tested the number and species richness of seedlings observed in the soil segments (N = 320), using negative binomial generalized linear regression models, in which sampling layer and penetration resistance were the predictor variables. We ran the models for morphological groups (graminoids/forbs), ecological groups (grassland species/weeds) and life-form categories (short-lived/perennial). We also tested whether seed shape index, seed mass, water requirement or salt tolerance of the species influence the vertical distribution of their seed bank. Results: Germinable seed density and species richness in the seed bank decreased with increasing soil depth and penetration resistance. However, we detected nine germinable seeds of six species even in the deepest soil layer. Forbs, grassland species and short-lived species occurred in large abundance in deep layers, from where graminoids, weeds and perennial species were missing. Round-shaped seeds were more abundant in deeper soil layers compared to elongated ones, but seed mass and ecological indicator values did not influence the vertical seed bank distribution. Our research draws attention to the potential ecological importance of the deeply buried seeds that may be a source of recovery after severe disturbance. As Vertisols cover 335 million hectares worldwide, these findings can be relevant for many regions and ecosystems globally. We highlight the need for similar studies in other soil and habitat types to test whether the presence of deep buried seeds is specific to soils with Vertic characteristics.

[Growth hormone receptor antagonist in the treatment of acromegaly]. / Növekedésihormonreceptor-antagonista alkalmazásának lehetoségei acromegaliában.

Exploration of construction, function and interaction of human growth hormone and growth hormone receptor in details resulted in the innovation of the new growth hormone receptor antagonist, pegvisomant. Pegvisomant with different mechanism of action extended the tools of medical management of acromegaly. Importance of the novel treatment modality is high. In one hand the necessity of the strict control of growth hormone/insulin-like growth factor-I axis has been proven regarding the mortality of the disease. On the other hand, despite the use of all current modes of treatment (surgery, radiotherapy, dopamine agonists, somatostatin analogs), a significant cohort of patients with acromegaly remains inadequately controlled. Pegvisomant has been registered in 2004. Since 2006, it has been used in Hungary for the treatment of acromegaly in patients who have had an inadequate response to surgery and/or radiation therapy and/or other medical therapies, or for whom these therapies are not appropriate. Clinical use of pegvisomant in the treatment of acromegaly is effective, well tolerated, and safe, based on international Acrostudy database. In order to improve the efficacy of therapy clinical trials started with pegvisomant and somatostatin analog combination treatment. Evidence of several further effects of the growth hormone/insulin-like growth factor-I axis suggests other potential uses of growth hormone receptor antagonists.

Vicinal difunctionalization of carbon-carbon double bond for the platform synthesis of trifluoroalkyl amines.

Regioselective vicinal diamination of carbon-carbon double bonds with two different amines is a synthetic challenge under transition metal-free conditions, especially for the synthesis of trifluoromethylated amines. However, the synthesis of ethylene diamines and fluorinated amine compounds is demanded, especially in the pharmaceutical sector. Herein, we demonstrate that the controllable double nucleophilic functionalization of an activated alkene synthon, originated from a trifluoropropenyliodonium salt with two distinct nucleophiles, enables the selective synthesis of trifluoromethylated ethylene amines and diamines on broad scale with high efficiency under mild reaction conditions. Considering the chemical nature of the reactants, our synthetic approach brings forth an efficient methodology and provides versatile access to highly fluorinated amines.

[The motivational value foundations in the choice of career among professional nursing students and students studying at teacher's college]. / Pályaválasztási motiváció értékrendi alapjai diplomásápoló- és tanárképzô fôiskolai hallgatók körében.

UNLABELLED: For the profession of teachers and nurses we need well-trained, highly qualified employees with a sense of vocation. AIM: A comparative analysis of motivation in the choice of career among professional nursing students and teacher-students. METHODS: This analysis was done in Hungary among professional nursing students and students participating in teacher training. In this sample 783 students were analysed. RESULTS: In the choice of career of nurses and teachers the primary motivation is of altruistic nature and also the human characteristics of the chosen career. According to genders in the case of female interviewed people we got a higher value than in the case of males in connection with "Helping people". It is more typical in the case of professional nursing students to choose the career as early as in their childhood. Choosing the career at a later age is typical for those who are teacher-students. CONCLUSION: As a consequence of our rapid economic changes or because of career dissatisfaction, we have to face the fact that the qualifications obtained at a young age will not last for a life time, and the majority of people are forced to change their jobs several times during their lives. In harmonizing the demands of the labour market and education, those people who take part in professional education and training have a professional advantage.

[Similarities and differences in the social background of female medical, nursing and public health visiting students]. / Orvostanhallgató-nôk, diplomásápoló-hallgatónôk és védônôhallgatók szociokulturális hátterében megmutatkozó azonosságok és különbségek.

UNLABELLED: According to our knowledge, there has never been a comprehensive research in Hungary dealing with healthcare university or college students' social background. AIM: The main objectives of our cross-section research were to analyze differences in the social background of female students who decided to become doctors, professional nurses and health visitors. METHOD: This research was conducted among female medical and nursing college students at the Semmelweis University. There were 295 students invited to participate, the response rate was 68,08% (N = 201). Data analysis was performed by SPSS software by using descriptive methods of statistics. RESULTS: We found a decisive difference among medical, nursing and health visitor students while analyzing a number of socio-demographic characteristics. Most medical students came from families where the parents had college or university degrees, but we can state that there is a minimal likelihood in the case of college students that they are descendants of parents with higher educational degrees. We did not find statistical differences in the three student sample groups regarding their marital status, but fewer nursing college students lived in marriage or household partnership. CONCLUSION: We found a significant difference in the social background of nursing college and medical students. The social disadvantages of nursing and health visitor students are more considerable than those of medical students.

Efficacy and tolerability of a fixed low-dose combination of cinnarizine and dimenhydrinate in the treatment of vertigo: a 4-week, randomized, double-blind, active- and placebo-controlled, parallel-group, outpatient study.

BACKGROUND: Most cases of vertigo are attributable to both peripheral and central vestibular disorders. Therefore, it would be of interest to determine whether a combination therapy having both peripheral and central actions would translate into more efficient symptom relief. OBJECTIVE: This study was conducted to evaluate the efficacy and tolerability of a fixed low-dose combination of cinnarizine 20 mg + dimenhydrinate 40 mg in the treatment of vertigo of central, peripheral, or combined central/peripheral origin. METHODS: This was a prospective, multicenter, randomized, double-blind, active- and placebo-controlled, parallel-group, outpatient study in men and women (age >30 years) with central, peripheral, or combined central/peripheral vestibular vertigo. Patients who assessed > or =1 vertigo symptom as being of medium intensity (> or =2) on a 5-point visual analog scale (from 0 = no symptoms to 4 = very severe symptoms) and who had abnormal vestibulospinal movement patterns on cramocorpography were eligible. Patients were randomly assigned to receive 1 tablet of the fixed combination of cinnarizine 20 mg + dimenhydrinate 40 mg, cinnarizine 50 mg, dimenhydrinate 100 mg, or placebo 3 times daily for 4 weeks. The primary efficacy end point was the decrease in mean vertigo score (MVS), which was composed of 12 individual vertigo symptoms, each assessed on the 5-point visual analog scale after 4 weeks of treatment. RESULTS: The study enrolled 246 patients, of whom 239 were evaluable for efficacy. Approximately two thirds of the efficacy population were female and one third male. The mean age was 51.3 years, and the mean duration of vertigo was 2.6 years. The least squares mean (SD) change from baseline in MVS was significantly greater in the group receiving the fixed combination (1.37 [0.66]) than in any of the comparator groups (cinnarizine 50 mg: 0.87 [0.53]; dimenhydrinate 100 mg: 0.83 [0.66]; placebo: 0.76 [0.48]; all comparisons, P < 0.001). The differences were clinically relevant, based on the Mann-Whitney estimator. The incidence of vertigo-associated nausea was significantly reduced in the fixed-combination group relative to the comparator groups (P< or = 0.016). Thirty-four patients reported adverse events, 6 each in the fixed combination and placebo groups, 12 in the cinnarizine group, and 10 in the dimenhydrinate group. None of these adverse events were considered serious. After 4 weeks of treatment, the tolerability of treatment was rated as very good or good by 57 (96.6%) patients in the fixed-combination group; the values for cinnarizine, dimenhydrinate, and placebo were 54 (93.1%), 42 (72.4%), and 50 (87.7%), respectively. CONCLUSIONS: In this study, the fixed low-dose combination of cinnarizine 20 mg + dimenhydrinate 40 mg was effective, clinically beneficial, and well tolerated in patients with vestibular vertigo of central and/or peripheral origin. It was significantly more effective in reducing the MVS compared with placebo and the routinely prescribed higher doses of cinnarizine (50 mg) and dimenhydrinate (100 mg).

The DNA-binding box of human SPARTAN contributes to the targeting of Polη to DNA damage sites.

Inappropriate repair of UV-induced DNA damage results in human diseases such as Xeroderma pigmentosum (XP), which is associated with an extremely high risk of skin cancer. A variant form of XP is caused by the absence of Polη, which is normally able to bypass UV-induced DNA lesions in an error-free manner. However, Polη is highly error prone when replicating undamaged DNA and, thus, the regulation of the proper targeting of Polη is crucial for the prevention of mutagenesis and UV-induced cancer formation. Spartan is a novel regulator of the damage tolerance pathway, and its association with Ub-PCNA has a role in Polη targeting; however, our knowledge about its function is only rudimentary. Here, we describe a new biochemical property of purified human SPARTAN by showing that it is a DNA-binding protein. Using a DNA binding mutant, we provide in vivo evidence that DNA binding by SPARTAN regulates the targeting of Polη to damage sites after UV exposure, and this function contributes highly to its DNA-damage tolerance function.

Panic disorder in otoneurological experience.

The evaluation of cochleovestibular dysfunction in psychiatric patients often causes a difficult problem in neurootological experience. The authors discuss here the neurobiological basis of panic disorders and cochleovestibular dysfunction. In this multicenter study, we examined 63 patients with vertigo and panic disease. Twenty patients with primary panic disease and consecutive vertigo composed group 1, whereas group 2 comprised 43 vertiginous patients with secondary panic disease. The most interesting question is whether the patients have an organic vestibular lesion, which would explain why vertigo alone is the problematic symptom in these panic patients, whereas in other patients, panic disease can cause other severe symptoms that resemble heart attack, dyspnea, or abdominal crisis. Vertigo has a bidirectional connection with psychiatric disorders. The panic disorder can be superimposed on chronic vertigo, and psychiatric patients with a cochleovestibular lesion have diminished chances for complete recovery. The examination of psychiatric patients with vertigo is very time consuming and requires much more empathy than does examination of vertiginous patients with a normal mental state. Anxiety provokes somatic and behavioral symptoms in most such patients. The treatment of vertigo in panic patients and of the panic disorder in vertiginous patients requires cooperation between neurootologist and psychiatrist.

[Spatial standardization of [15O]-butanol PET images using T1-weighted MRI data]. / [15O]-butanol PET-vizsgálatok térbeli standardizálása szegmentált, T1-súlyozott MRI-felvételek segítségével.

Population averaged brain activation studies require the spatial standardization of the individual perfusion PET images. This procedure is usually supported by T1-weighted MRI images. The authors developed a segmentation technique to improve the automatized transformation of the individual MRI images into Talairach space. It was for the first time in Hungary that population averages of standardized T1-weighted MRI and [15O]-butanol PET images of the brain were created after validation of the procedure using data from 23 healthy volunteers. The newly developed method offers a solution for the automatized processing of primary data from brain activation experiments prior to statistical analysis.

[Effect of pathologic and induced peripheral vestibular balance disturbance on the central nervous system]. / Patológiás és indukált perifériás vestibularis egyensúlyzavar központi idegrendszeri hatása.

The authors investigated the central projection of excitement in acute stage vestibular neuronitis using positron emission tomography. The changes in the pattern of regional cerebral blood flow caused by the disease were compared with the effect of cold caloric stimulation known to provoke similar signs. It was concluded that the involved brain regions overlapped each other only partially. The mismatch could be explained by the compensatory processes developing during the disease. These processes do not normally develop during the caloric vestibular stimulation because of its short duration.

Margatoxin is a non-selective inhibitor of human Kv1.3 K+ channels.

Margatoxin (MgTx), an alpha-KTx scorpion toxin, is considered a selective inhibitor of the Kv1.3K + channel. This peptide is widely used in ion channel research; however, a comprehensive study of its selectivity with electrophysiological methods has not been published yet. The lack of selectivity might lead to undesired side effects upon therapeutic application or may lead to incorrect conclusion regarding the role of a particular ion channel in a physiological or pathophysiological response either in vitro or in vivo. Using the patch-clamp technique we characterized the selectivity profile of MgTx using L929 cells expressing mKv1.1 channels, human peripheral lymphocytes expressing Kv1.3 channels and transiently transfected tsA201 cells expressing hKv1.1, hKv1.2, hKv1.3, hKv1.4-IR, hKv1.5, hKv1.6, hKv1.7, rKv2.1, Shaker-IR, hERG, hKCa1.1, hKCa3.1 and hNav1.5 channels. MgTx is indeed a high affinity inhibitor of Kv1.3 (Kd = 11.7 pM) but is not selective, it inhibits the Kv1.2 channel with similar affinity (Kd = 6.4 pM) and Kv1.1 in the nanomolar range (Kd = 4.2 nM). Based on our comprehensive data MgTX has to be considered a non-selective Kv1.3 inhibitor, and thus, experiments aiming at elucidating the significance of Kv1.3 in in vitro or in vivo physiological responses have to be carefully evaluated.