Pleiotropic Effects of Calcium Channel Blockers

Clinical trials have reported reduced cardiovascular events with certain antihypertensive agents at a rate that could not be predicted by changes in brachial arterial pressure alone. These findings may be explained, in part, by pleiotropic effects of these agents and modulation of central blood pressures. This review focuses on the mechanisms by which calcium channel blockers exert pleiotropic effects, both alone and in combination with statins and inhibitors of the renin-angiotensin system. The essential role of nitric oxide (NO) in maintaining endothelial function and the relationship between NO and reactive oxygen species are discussed in the context of the etiology of hypertension. The importance of managing global cardiovascular risk is emphasized, as hypertension commonly clusters with dyslipidemia and loss of glucose control. From a mechanistic viewpoint, these risk factors contribute to endothelial dysfunction, oxidative stress, and inflammation in a synergistic fashion. A greater understanding of the mechanisms of actions of these cardiovascular agents may lead to more effective drug combinations, to the benefit of individual patients. Furthermore, by elucidating the biological mechanisms by which cardiovascular risk factors lead to vascular injury, we may highlight common pathways and identify novel therapeutic targets

Direct evidence for cholesterol crystalline domains in biological membranes: role in human pathobiology

AbstractThis review will discuss the use of small-angle X-ray diffraction approaches to study the organization of lipids in plasma membranes derived from two distinct mammalian cell types: arterial smooth muscle cells and ocular lens fiber cells. These studies indicate that cholesterol at an elevated concentration can self-associate and form immiscible domains in the plasma membrane, a phenomenon that contributes to both physiologic and pathologic cellular processes, depending on tissue source. In plasma membrane samples isolated from atherosclerotic smooth muscle cells, the formation of sterol-rich domains is associated with loss of normal cell function, including ion transport activity and control of cell replication. Analysis of meridional diffraction patterns from intact and reconstituted plasma membrane samples indicates the presence of an immiscible cholesterol domain with a unit cell periodicity of 34 Å, consistent with a cholesterol monohydrate tail-to-tail bilayer, under disease conditions. These cholesterol domains were observed in smooth muscle cells enriched with cholesterol in vitro as well as from cells obtained ex vivo from an animal model of atherosclerosis. By contrast, well-defined cholesterol domains appear to be essential to the normal physiology of fiber cell plasma membranes of the human ocular lens. The organization of cholesterol into separate domains underlies the role of lens fiber cell plasma membranes in maintaining lens transparency. These domains may also interfere with cataractogenic aggregation of soluble lens proteins at the membrane surface. Taken together, these analyses provide examples of both physiologic and pathologic roles that sterol-rich domains may have in mammalian plasma membranes. These findings support a model of the membrane in which cholesterol aggregates into structurally distinct regions that regulate the function of the cell membrane

Are dietary fish oil supplements appropriate for dyslipidemia management? A review of the evidence

PURPOSE OF REVIEW: The purpose of this review is to assess whether dietary fish oil supplements can be appropriate for patients with elevated triglycerides and cardiovascular risk based on a comprehensive analysis of their composition, and level of regulatory oversight. RECENT FINDINGS: Approximately 19 million people in the United States take fish oil supplements, many for the purpose of treating or preventing heart disease. Unlike prescription products, fish oil supplements are classified as food by the Food and Drug Administration (FDA) and are not required to undergo manufacturing oversight or clinical testing. Analysis of widely used dietary fish oil supplements show that they may have lower amounts of omega-3 than advertised as well as significant levels of saturated fat and oxidized oils which actually may contribute to dyslipidemia. Clinical outcome trials have failed to show a consistent cardiovascular benefit with fish oil supplements and other low-dose mixed omega-3 fatty acids. SUMMARY: In light of limited regulatory oversight and evidence of quality concerns, dietary fish oil supplements are not an appropriate substitute for FDA approved prescription omega-3 fatty acids for their indicated use in treatment of elevated triglycerides or the prevention of cardiovascular events

Improving outcomes for older people in the emergency department : a review of reviews

Background: There has been a recognised trend of increasing use of emergency and urgent care and emergency departments (EDs) by older people, which is marked by a substantial evidence base reporting interventions for this population and guidance from key organisations. Despite this, outcomes for this population remain suboptimal. A plethora of reviews in this area provides challenges for clinicians and commissioners in determining which interventions and models of care best meet people’s needs. The aim of this review was to identify effective ED interventions which have been reported for older people, and to provide a clear summary of the myriad reviews and numerous intervention types in this area. Methods: A review of reviews, reporting interventions for older people, either initiated or wholly delivered within the ED. Results: A total of 15 review articles describing 83 primary studies met our content and reporting standards criteria. The majority (n=13) were systematic reviews (four using meta-analysis.) Across the reviews, 26 different outcomes were reported with inconsistency. Follow-up duration varied within and across the reviews. Based on how authors had reported results, evidence clusters were developed: (1) staff-focused reviews, (2) discharge intervention reviews, (3) population-focused reviews and (4) intervention component reviews. Conclusions: The evidence base describing interventions is weak due to inconsistent reporting, differing emphasis placed on the key characteristics of primary studies (staff, location and outcome) by review authors and varying quality of reviews. No individual interventions have been found to be more promising, but interventions initiated in the ED and continued into other settings have tended to result in more favourable patient and health service outcomes. Despite many interventions reported within the reviews being holistic and patient focused, outcomes measured were largely service focused. PROSPERO registration number: PROSPERO CRD42018111461

The favorable kinetics and balance of nebivolol-stimulated nitric oxide and peroxynitrite release in human endothelial cells

Background: Nebivolol is a third-generation beta-blocker used to treat hypertension. The vasodilation properties of nebivolol have been attributed to nitric oxide (NO) release. However, the kinetics and mechanism of nebivolol-stimulated bioavailable NO are not fully understood. Methods: Using amperometric NO and peroxynitrite (ONOO-) nanosensors, β3-receptor (agonist: L-755,507; antagonists: SR59230A and L-748,337), ATP efflux (the mechanosensitive ATP channel blocker, gadolinium) and P2Y-receptor (agonists: ATP and 2-MeSATP; antagonist: suramin) modulators, superoxide dismutase and a NADPH oxidase inhibitor (VAS2870), we evaluated the kinetics and balance of NO and ONOO- stimulated by nebivolol in human umbilical vein endothelial cells (HUVECs). NO and ONOO- were measured with nanosensors (diameter ~ 300 nm) placed 5 ± 2 μm from the cell membrane and ATP levels were determined with a bioluminescent method. The kinetics and balance of nebivolol-stimulated NO and ONOO- were compared with those of ATP, 2-MeSATP, and L-755,507. Results: Nebivolol stimulates endothelial NO release through β3-receptor and ATP-dependent, P2Y-receptor activation with relatively slow kinetics (75 ± 5 nM/s) as compared to the kinetics of ATP (194 ± 10 nM/s), L-755,507 (108 ± 6 nM/s), and 2-MeSATP (105 ± 5 nM/s). The balance between cytoprotective NO and cytotoxic ONOO- was expressed as the ratio of [NO]/[ONOO-] concentrations. This ratio for nebivolol was 1.80 ± 0.10 and significantly higher than that for ATP (0.80 ± 0.08), L-755,507 (1.08 ± 0.08), and 2-MeSATP (1.09 ± 0.09). Nebivolol induced ATP release in a concentration-dependent manner. Conclusion: The two major pathways (ATP efflux/P2Y receptors and β3 receptors) and several steps of nebivolol-induced NO and ONOO- stimulation are mainly responsible for the slow kinetics of NO release and low ONOO-. The net effect of this slow kinetics of NO is reflected by a favorable high ratio of [NO]/[ONOO-] which may explain the beneficial effects of nebivolol in the treatment of endothelial dysfunction, hypertension, heart failure, and angiogenesis

Optical extinction efficiency measurements on fine and accumulation mode aerosol using single particle cavity ring-down spectroscopy

We report a new single aerosol particle approach using cavity ringdown spectroscopy to accurately determine optical extinction cross sections at multiple wavelengths.</p

‘In the shower crying ...but we came back in the following day and did it all again’. Distress and resilience in care home staff during the COVID-19 pandemic – A qualitative interview study.

Abstract:\ua9 The Author(s) 2024.Background: Care homes (long-term care facilities) were profoundly impacted early in the COVID-19 pandemic, both in terms of resident mortality and restrictions for infection control. This study investigated the impact on the emotional well-being of care home staff of challenges faced at this time, and the strategies used to manage them. Methods: Semi-structured interviews conducted October 2020-June 2021 with care home staff and health service staff working with them explored the impact of the early waves of the COVID-19 pandemic (March 2020-June 2021). Interview data were analysed using reflexive thematic analysis. Results: Interview participants were 16 care home staff and 10 health service staff. Analysis generated four key themes: 1)Anxiety and distress, 2)Overwhelming workload, 3)Pulling through; and 4)Resilience in a time of crisis. Care home staff experienced Anxiety and distress due to uncertainty of what to expect; witnessing illness and deaths of residents; concerns regarding their own health, and sometimes feeling their work was under-recognised. They also experienced an Overwhelming workload due to infection control measures, caring for sick residents and reduction in external healthcare support. Our theme of Pulling through reflects the peer support and problem-solving strategies with which care home staff managed the impact of the pandemic, along with a sense of responsibility and meaning towards their work. An overarching theme of Resilience in a time of crisis drew on the other three themes and describes how many staff managed, maintained, and often increased their work despite the challenges of the pandemic. Participants also described increasing emotional fatigue as the pandemic continued. Conclusions: This paper builds on literature on the emotional impact of the pandemic on care home staff, also exploring ways that staff responded to this impact. These findings can help inform planning for future crises including disease outbreaks, and raise important questions for further work to develop pandemic preparedness in care homes and beyond. They also raise wider questions about the current cultural status of care work, which may have exposed care home staff to greater risk of distress, and which contrasts with the professionalism and responsibility shown by staff in response to pandemic challenge