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Objective: Identify the impact of COVID-19 lockdown restrictions on the vitamin D status of individuals in the west of Ireland. Design: Cross-sectional study. Setting: Adults who had wintertime serum 25(OH)D analysis completed in Galway University Hospital. Participants: A total of 16,725 participants (2015–2020 (n = 13,449) and 2020–2021 (n = 3276)). Baseline demographics; sex, age, origin of the sample and the date of sample collection. Results: Median serum vitamin D and serum vitamin D3 concentrations were higher in the 5-month period from October–February 2020–2021 (61 nmol/L (± 36–85 nmol/L) and 60 nmol/L (± 34–85 nmol/L)) respectively, than for the corresponding 5-month period (October–February) in 2015–2020 (53 nmol/L (± 32–78 nmol/L) and 51 nmol/L (± 30–77 nmol/L)) respectively. These changes coincided with a decline in the prevalence of deficiency. In the 5-month period October–February 2020–2021, 19.2% of the population were vitamin D deficient (< 30 nmol/L) compared to 22.5% in the corresponding 5-month period in 2015–2020, and 38.1% were vitamin D deficient (< 50 nmol/L) in the 5-month period October–February 2020–2021 compared to 46.6% in the corresponding 5-month period in 2015–2020. Males were more likely to be deficient at both thresholds (p < 0.001). For the total cohort, at the < 30 nmol/L threshold, inpatients (25.5%) and nursing home residents (34.1%) had higher prevalence of deficiency. Conclusions: Vitamin D levels were higher in the 5-month period of October–February 2020–2021, and this precipitated a decline in deficiency at both thresholds, indicating that lockdown coincided with enhanced vitamin D status. We postulate that it may be attributable to changes in diet and/or supplementation, or increased sun exposure, but further confirmatory studies are required. [ABSTRACT FROM AUTHOR]

Abstract Background PGF2alpha exerts a significant contractile effect on myometrium and is central to human labour. THG113.31, a specific non-competitive PGF2alpha receptor (FP) antagonist, exerts an inhibitory effect on myometrial contractility. The BKCa channel is ubiquitously encountered in human uterine tissue and plays a significant role in modulating myometrial cell membrane potential and excitability. The objective of this study was to investigate potential BKCa channel involvement in the response of human myometrium to THG113.31. Methods Single and whole-cell electrophysiological BKCa channel recordings from freshly dispersed myocytes, were investigated in the presence and absence of THG113.31. Functional studies investigated the effects of THG113.31 on isolated spontaneous myometrial contractions, in the presence and absence of the BKCa channel blocker, iberiotoxin. Results Single channel recordings identified the BKCa channel as a target of THG113.31. THG113.31 significantly increased the open state probability of these channels [control 0.023+/-0.006; 10 microM THG113.31 0.087+/-0.012 (P = 0.009); and 50 microM THG113.31 0.1356+/-0.018 (P = 0.001)]. In addition, THG113.31 increased whole-cell BKCa currents over a range of membrane potentials, and this effect was reversed by 100 nanoM IbTX. Isometric tension studies demonstrated that THG113.31 exerted a significant concentration-dependent relaxant effect on human myometrial tissue and pre-incubation of strips with IbTX abolished this effect on spontaneously occurring contractions. Conclusion These data suggests that activation of the BKCa channel may contribute, at least partially, to the uterorelaxant effect of THG113.31.

Context: Beta3-adrenoreceptor modulation in human myometrium during pregnancy is linked functionally to myometrial inhibition. Maxi-K+ channels (BK(Ca)) play a significant role in modulating cell membrane potential and excitability., Objective: This study was designed to investigate the potential involvement of BK(Ca) channel function in the response of human myometrium to beta3-adrenoceptor activation., Design: Single and whole-cell electrophysiological BK(Ca) channel recordings from freshly dispersed myocytes were obtained in the presence and absence of BRL37344, a specific beta3-adrenoreceptor agonist. The in vitro effects of BRL37344 on isolated myometrial contractions, in the presence and absence of the specific BK(Ca) channel blocker, iberiotoxin (IbTX), were investigated., Setting: The study was carried out at the Clinical Science Institute., Patients or Other Participants: Myometrial biopsies were obtained at elective cesarean delivery., Intervention: No intervention was applied., Main Outcome Measures: Open state probability of single channel recordings, whole cell currents, and myometrial contractile activity were measured., Results: Single-channel recordings identified the BK(Ca) channel as a target of BRL37344. BRL37344 significantly increased the open state probability of this channel in a concentration-dependent manner (control 0.031 +/- 0.004; 50 microM BRL37344 0.073 +/- 0.005 (P < 0.001); and 100 microM BRL37344 0.101 +/- 0.005 (P < 0.001). This effect was completely blocked after preincubation of the cells with 1 microM bupranolol, a nonspecific beta-adrenoreceptor blocker, or 100 nM SR59230a, a specific beta3-adrenoreceptor antagonist. In addition, BRL37344 increased whole-cell currents over a range of membrane potentials, and this effect was reversed by 100 nM IbTX. In vitro isometric tension studies demonstrated that BRL37344 exerted a significant concentration-dependent relaxant effect on human myometrial tissue (P < 0.05), and preincubation of these strips with IbTX attenuated this effect on both spontaneous and oxytocin-induced contractions (44.44 and 57.84% at 10(-5) M, respectively)., Conclusions: These findings outline that activation of the BK(Ca) channel may explain the potent uterorelaxant effect of beta3-adrenoreceptor agonists.