Mammalian transient receptor potential channels (TRPCs) form a family of Ca2؉ -permeable cation channels currently consisting of seven members, TRPC1-TRPC7. These channels have been proposed to be molecular correlates for capacitative Ca 2؉ entry channels. There are only a few studies on the regulation and properties of the subfamily consisting of TRPC4 and TRPC5, and there are contradictory reports concerning the possible role of intracellular Ca 2؉ store depletion in channel activation. We therefore investigated the regulatory and biophysical properties of murine TRPC4 and TRPC5 (mTRPC4/5) heterologously expressed in human embryonic kidney cells. Activation of G q/11 -coupled receptors or receptor tyrosine kinases induced Mn 2؉ entry in fura-2-loaded mTRPC4/5-expressing cells. Accordingly, in whole-cell recordings, stimulation of G q/11 -coupled receptors evoked large, nonselective cation currents, an effect mimicked by infusion of guanosine 5-3-O-(thio)triphosphate (GTP␥S). However, depletion of intracellular Ca2؉ stores failed to activate mTRPC4/5. In inside-out patches, single channels with conductances of 42 and 66 picosiemens at ؊60 mV for mTRPC4 and mTRPC5, respectively, were stimulated by GTP␥S in a membrane-confined manner. Thus, mTRPC4 and mTRPC5 form nonselective cation channels that integrate signaling pathways from G-protein-coupled receptors and receptor tyrosine kinases independently of store depletion. Furthermore, the biophysical properties of mTRPC4/5 are inconsistent with those of I CRAC , the most extensively characterized store-operated current.

SUMMARY1. Ca2+ currents were recorded using the whole-cell mode of the patch-clamp technique from mouse pancreatic B-cells kept in culture for 1-4 days. B-cells were identified in the cell-attached mode by their response to a change in the glucose concentration from 3 to 15 or 20 mm or by their inward currents.2. Only one component of Ca2+ current was observed in these cells, which activated at potentials > -50 mV and was blocked by nitrendipine (5/M), and increased in amplitude by CGP 28392 (5 /tM).3. During maintained depolarizations the Ca2+ current inactivated considerably but not completely. Inactivation was most marked at potentials where the Ca2+ currents were large, but in general was slower for currents at potentials > 0 mV than at more negative potentials.4. Two-pulse experiments showed that the inactivation curve for the Ca2+ current was U-shaped, returning to unity at potentials approaching the Ca2+ equilibrium potential. Measurements of Ca2+ entry showed that inactivation was dependent on the amount of Ca2+ entering during the pre-pulse, independent of the pre-pulse potential.5. Ca2+ currents were not appreciably slowed when BAPTA, a faster buffer of Ca2+, replaced EGTA in the pipette solution.6. Replacement of Ca2+ in the external solution by Ba2+ increased the amplitude of the inward current and largely abolished inactivation. Large inward currents through Ca2+ channels were observed in the absence of divalent cations in the external solution (+ EGTA), which were presumably carried by Na+. These currents did not inactivate during 150 ms depolarizations, but were increased in amplitude by CGP 28392 (5 /M) and blocked by D600 (30 FM).7. The observations suggest that normal mouse pancreatic B-cells have only one type of Ca2+ channel which is dihydropyridine sensitive and inactivates by a mechanism which is almost purely Ca2+ dependent. Inactivation of the Ca2+ current will probably be important in the control of Ca2+ entry during glucose-induced electrical activity.

SUMMARY1. The effects of intracellular injection of Ca, EGTA and EGTA/Ca buffers on inward currents flowing through the Ca channel in Helix aspersa neurones were studied under voltage clamp.2. Inward currents were reversibly reduced by Ca injection. The extent of the reduction was dependent on the size and duration of the injection. Recovery from injection was exponential with a time constant around 18 s at 18-20 'C.3. In our salines, which contained tetraethylammonium chloride and 4-aminopyridine, no outward current was activated by Ca injection at the holding potential. A given Ca injection reduced the inward current by the same fraction in 25 mm-and 2-5 mM-Sr and also at different test potentials. We conclude that Ca injection does not activate an outward current. Mean resting ionized internal

We have identified prognostic factors and report progression to liver failure in 53% of NCIPH patients followed-up at our center. Our data supports a role for intestinal disease in the pathogenesis of intrahepatic portal vein occlusion leading to NCIPH.

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Summary Coronavirus 19 (COVID‐19) has been associated with both transient and persistent systemic symptoms that do not appear to be a direct consequence of viral infection. The generation of autoantibodies has been proposed as a mechanism to explain these symptoms. To understand the prevalence of autoantibodies associated with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, we investigated the frequency and specificity of clinically relevant autoantibodies in 84 individuals previously infected with SARS‐CoV‐2, suffering from COVID‐19 of varying severity in both the acute and convalescent setting. These were compared with results from 32 individuals who were on the intensive therapy unit (ITU) for non‐COVID reasons. We demonstrate a higher frequency of autoantibodies in the COVID‐19 ITU group compared with non‐COVID‐19 ITU disease control patients and that autoantibodies were also found in the serum 3–5 months post‐COVID‐19 infection. Non‐COVID patients displayed a diverse pattern of autoantibodies; in contrast, the COVID‐19 groups had a more restricted panel of autoantibodies including skin, skeletal muscle and cardiac antibodies. Our results demonstrate that respiratory viral infection with SARS‐CoV‐2 is associated with the detection of a limited profile of tissue‐specific autoantibodies, detectable using routine clinical immunology assays. Further studies are required to determine whether these autoantibodies are specific to SARS‐CoV‐2 or a phenomenon arising from severe viral infections and to determine the clinical significance of these autoantibodies.

Background Vaccination prevents severe morbidity and mortality from COVID-19 in the general population. The immunogenicity and efficacy of SARS-CoV-2 vaccines in patients with antibody deficiency is poorly understood. Objectives COVID-19 in patients with antibody deficiency (COV-AD) is a multi-site UK study that aims to determine the immune response to SARS-CoV-2 infection and vaccination in patients with primary or secondary antibody deficiency, a population that suffers from severe and recurrent infection and does not respond well to vaccination. Methods Individuals on immunoglobulin replacement therapy or with an IgG less than 4 g/L receiving antibiotic prophylaxis were recruited from April 2021. Serological and cellular responses were determined using ELISA, live-virus neutralisation and interferon gamma release assays. SARS-CoV-2 infection and clearance were determined by PCR from serial nasopharyngeal swabs. Results A total of 5.6% (n = 320) of the cohort reported prior SARS-CoV-2 infection, but only 0.3% remained PCR positive on study entry. Seropositivity, following two doses of SARS-CoV-2 vaccination, was 54.8% (n = 168) compared with 100% of healthy controls (n = 205). The magnitude of the antibody response and its neutralising capacity were both significantly reduced compared to controls. Participants vaccinated with the Pfizer/BioNTech vaccine were more likely to be seropositive (65.7% vs. 48.0%, p = 0.03) and have higher antibody levels compared with the AstraZeneca vaccine (IgGAM ratio 3.73 vs. 2.39, p = 0.0003). T cell responses post vaccination was demonstrable in 46.2% of participants and were associated with better antibody responses but there was no difference between the two vaccines. Eleven vaccine-breakthrough infections have occurred to date, 10 of them in recipients of the AstraZeneca vaccine. Conclusion SARS-CoV-2 vaccines demonstrate reduced immunogenicity in patients with antibody deficiency with evidence of vaccine breakthrough infection.

1 The vasodilator and antihypertensive properties of pinacidil, cromakalim (BRL 34915), nicorandil and minoxidil sulphate may be due, at least in part, to their ability to open K+ channels in vascular smooth muscles. In this study, mouse pancreatic islets were used to determine whether these drugs affect insulin release by acting on K + channels of fl-cells. Their effects were compared to those of diazoxide. 2 Diazoxide caused a dose-dependent inhibition of insulin release by islets incubated with 15mM glucose (93% at 1OOM). Pinacidil inhibited release by 36 and 72% at 100 and 500 M, respectively.Cromakalim and nicorandil were less effective (35 and 25% inhibition at 50OpM). Minoxidil sulphate increased insulin release at 500 pM. 3 In the presence of 7mm glucose and in the absence of Ca2+ (to avoid activation of Ca2+-dependent K+ channels), 86Rb efflux from islet cells was increased by 100-50OM pinacidil and 5OM nicorandil, which were, however, less potent than diazoxide. Cromakalim was ineffective, whereas 5OM minoxidil sulphate decreased the efflux rate. In the absence of glucose and presence of Ca2", 500 JIM cromakalim and minoxidil sulphate inhibited 86Rb efflux. 5 ATP-sensitive K+ currents were studied in single fl-cells by the whole cell patch-clamp technique. Pinacidil increased the current less than did diazoxide. In contrast, cromakalim and minoxidil sulphate decreased K+-currents whilst nicorandil was without effect. 6 It is concluded that pinacidil, like diazoxide, inhibits insulin release from fl-cells by opening ATP-sensitive K+ channels, whereas the smaller inhibitory effects of cromakalim and nicorandil may involve actions other than on K+ channels in these cells. Minoxidil sulphate potentiates glucose-induced insulin release, probably by inhibiting ATP-sensitive K+ channels. However, all these effects of the vasodilators are only seen at high concentrations and are thus unlikely to occur in vivo.