Tension in contracting muscle fiber under conditions of ramp stretching rapidly increases, but after reaching a critical stretch Pc sharply decreases. To find out the cause of these changes in muscle fiber tension, we stopped stretching before and after reaching Pc and left the fiber stretched for 50 msec. After rapid tension drop, the transient tension rise not accompanied by fiber stiffness increase was observed only in fibers heated to 25°C and stretched to Pc. Under other experimental conditions, this growth was absent. We suppose that stretch of the fiber to Pc induces transition of stereo-specifically attached myosin heads to pre-power stroke state and when the stretching is stopped, they make their step on actin and generate force. When the tension reaches Pc, all stereospecifically attached myosin heads turn out to be non-stereospecifically, or weakly attached to actin, and are unable to make the force-generating step.

Possible Cause of Nonlinear Tension Rise in Activated Muscle Fiber during Stretching.

Bulletin of Experimental Biology and Medicine

The 6th International Conference, "Controversies in Vitamin D," was convened to discuss controversial topics, such as vitamin D metabolism, assessment, actions, and supplementation. Novel insights into vitamin D mechanisms of action suggest links with conditions that do not depend only on reduced solar exposure or diet intake and that can be detected with distinctive noncanonical vitamin D metabolites. Optimal 25-hydroxyvitamin D (25(OH)D) levels remain debated. Varying recommendations from different societies arise from evaluating different clinical or public health approaches. The lack of assay standardization also poses challenges in interpreting data from available studies, hindering rational data pooling and meta-analyses. Beyond the well-known skeletal features, interest in vitamin D's extraskeletal effects has led to clinical trials on cancer, cardiovascular risk, respiratory effects, autoimmune diseases, diabetes, and mortality. The initial negative results are likely due to enrollment of vitamin D-replete individuals. Subsequent post hoc analyses have suggested, nevertheless, potential benefits in reducing cancer incidence, autoimmune diseases, cardiovascular events, and diabetes. Oral administration of vitamin D is the preferred route. Parenteral administration is reserved for specific clinical situations. Cholecalciferol is favored due to safety and minimal monitoring requirements. Calcifediol may be used in certain conditions, while calcitriol should be limited to specific disorders in which the active metabolite is not readily produced in vivo. Further studies are needed to investigate vitamin D effects in relation to the different recommended 25(OH)D levels and the efficacy of the different supplementary formulations in achieving biochemical and clinical outcomes within the multifaced skeletal and extraskeletal potential effects of vitamin D.

Consensus Statement on Vitamin D Status Assessment and Supplementation: Whys, Whens, and Hows.

Endocrine Reviews

Tricuspid valve disease is an often underrecognized clinical problem that is associated with significant morbidity and mortality. Unfortunately, patients will often present late in their disease course with severe right-sided heart failure, pulmonary hypertension, and life-limiting symptoms that have few durable treatment options. Traditionally, the only treatment for tricuspid valve disease has been medical therapy or surgery; however, there have been increasing interest and success with the use of transcatheter tricuspid valve therapies over the past several years to treat patients with previously limited therapeutic options. The tricuspid valve is complex anatomically, lying adjacent to important anatomic structures such as the right coronary artery and the atrioventricular node, and is the passageway for permanent pacemaker leads into the right ventricle. In addition, the mechanism of tricuspid pathology varies widely between patients, which can be due to primary, secondary, or a combination of causes, meaning that it is not possible for 1 type of device to be suitable for treatment of all cases of tricuspid valve disease. To best visualize the pathology, several modalities of advanced cardiac imaging are often required, including transthoracic echocardiography, transesophageal echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging, to best visualize the pathology. This detailed imaging provides important information for choosing the ideal transcatheter treatment options for patients with tricuspid valve disease, taking into account the need for the lifetime management of the patient. This review highlights the important background, anatomic considerations, therapeutic options, and future directions with regard to treatment of tricuspid valve disease.

The Tricuspid Valve: A Review of Pathology, Imaging, and Current Treatment Options: A Scientific Statement From the American Heart Association.

Circulation

Deaths from the majority of cancers are falling globally, but the incidence and mortality from hepatocellular carcinoma (HCC) is increasing in the United Kingdom and in other Western countries. HCC is a highly fatal cancer, often diagnosed late, with an incidence to mortality ratio that approaches 1. Despite there being a number of treatment options, including those associated with good medium to long-term survival, 5-year survival from HCC in the UK remains below 20%. Sex, ethnicity and deprivation are important demographics for the incidence of, and/or survival from, HCC. These clinical practice guidelines will provide evidence-based advice for the assessment and management of patients with HCC. The clinical and scientific data underpinning the recommendations we make are summarised in detail. Much of the content will have broad relevance, but the treatment algorithms are based on therapies that are available in the UK and have regulatory approval for use in the National Health Service.

British Society of Gastroenterology guidelines for the management of hepatocellular carcinoma in adults.

Interstitial lung disease (ILD) consists of a group of pulmonary disorders characterized by inflammation and/or fibrosis of the lung parenchyma associated with progressive dyspnea that frequently results in end-stage respiratory failure. In the US, ILD affects approximately 650&#x202f;000 people and causes approximately 25&#x202f;000 to 30&#x202f;000 deaths per year.

The most common forms of ILD are idiopathic pulmonary fibrosis (IPF), which accounts for approximately one-third of all cases of ILD, hypersensitivity pneumonitis, accounting for 15% of ILD cases, and connective tissue disease (CTD), accounting for 25% of ILD cases. ILD typically presents with dyspnea on exertion. Approximately 30% of patients with ILD report cough. Thoracic computed tomography is approximately 91% sensitive and 71% specific for diagnosing subtypes of ILDs such as IPF. Physiologic assessment provides important prognostic information. A 5% decline in forced vital capacity (FVC) over 12 months is associated with an approximately 2-fold increase in mortality compared with no change in FVC. Antifibrotic therapy with nintedanib or pirfenidone slows annual FVC decline by approximately 44% to 57% in individuals with IPF, scleroderma associated ILD, and in those with progressive pulmonary fibrosis of any cause. For connective tissue disease-associated ILD, immunomodulatory therapy, such as tocilizumab, rituximab, and mycophenolate mofetil, may slow decline or even improve FVC at 12-month follow-up. Structured exercise therapy reduces symptoms and improves 6-minute walk test distance in individuals with dyspnea. Oxygen reduces symptoms and improves quality of life in individuals with ILD who desaturate below 88% on a 6-minute walk test. Lung transplant may improve symptoms and resolve respiratory failure in patients with end-stage ILD. After lung transplant, patients with ILD have a median survival of 5.2 to 6.7 years compared with a median survival of less than 2 years in patients with advanced ILD who do not undergo lung transplant. Up to 85% of individuals with end-stage fibrotic ILD develop pulmonary hypertension. In these patients, treatment with inhaled treprostinil improves walking distance and respiratory symptoms.

Interstitial lung disease typically presents with dyspnea on exertion and can progress to respiratory failure. First-line therapy includes nintedanib or pirfenidone for IPF and mycophenolate mofetil for ILD due to connective tissue disease. Lung transplant should be considered for patients with advanced ILD. In patients with ILD, exercise training improves 6-minute walk test distance and quality of life.

Interstitial Lung Disease: A Review.

JAMA

Ventilator Waveforms May Give Clues to Expiratory Muscle Activity.

American Journal of Respiratory and Critical Care Medicine

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease characterised by the presence of autoantibodies towards nuclear antigens, immune complex deposition, and chronic inflammation at classic target organs such as skin, joints, and kidneys. Despite substantial advances in the diagnosis and management of SLE, the burden of disease remains high. It is important to appreciate the typical presentations and the diagnostic process to facilitate early referral and diagnosis for patients. In most patients, constitutional, mucocutaneous, and musculoskeletal symptoms represent the earliest complaints; these symptoms can include fatigue, lupus-specific rash, mouth ulcers, alopecia, joint pain, and myalgia. In this Seminar we will discuss a diagnostic approach to symptoms in light of the latest classification criteria, which include a systematic evaluation of clinical manifestations (weighted within each domain) and autoantibody profiles (such as anti-double-stranded DNA, anti-Sm, hypocomplementaemia, or antiphospholipid antibodies). Non-pharmacotherapy management is tailored to the individual, with specific lifestyle interventions and patient education to improve quality of life and medication (such as hydroxychloroquine or immunosuppressant) adherence. In the last decade, there have been a few major breakthroughs in approved treatments for SLE and lupus nephritis, such as belimumab, anifrolumab, and voclosporin. However the disease course remains variable and mortality unacceptably high. Access to these expensive medications has also been restricted across different regions of the world. Nonetheless, understanding of treatment goals and strategies has improved. We recognise that the main goal of treatment is the achievement of remission or low disease activity. Comorbidities due to both disease activity and treatment adverse effects, especially infections, osteoporosis, and cardiovascular disease, necessitate vigilant prevention and management strategies. Tailoring treatment options to achieve remission, while balancing treatment-related comorbidities, are priority areas of SLE management.

Systemic lupus erythematosus.

Lancet

Dapagliflozin, a sodium-glucose cotransporter 2 inhibitor (SGLT2i), has shown demonstrated benefits for renal and cardiovascular outcomes in large clinical trials. However, short-term concerns regarding its impact on renal function and electrolyte balance exist. This study aimed to evaluate the short-term effects of dapagliflozin on renal function and electrolyte balance in patients newly prescribed the medication. A retrospective analysis of 246 patients who initiated dapagliflozin therapy was conducted. Serum creatinine, sodium, and potassium levels were measured at baseline (before dapagliflozin) and 5-8 days after initiation (endpoint). A Wilcoxon signed-rank test, Pearson's chi-square test, and Fischer's exact test were used for the data analysis. Glycemia and sodium levels were significantly higher at the baseline compared to the endpoint ( p &lt; 0.001). Conversely, creatinine and potassium levels were significantly higher at the endpoint than at the baseline ( p &lt; 0.001). The prevalence of hyponatremia and hyperkalemia were increased at the endpoint (17.5% vs. 10.2% and 16.7% vs. 8.9%, respectively). Although not statistically significant, a trend towards increased hyponatremia with the co-administration of furosemide was observed ( p = 0.089). No significant association was found between potassium-sparing medications ( p &gt; 0.05) and hyperkalemia, except for angiotensin receptor blockers ( p = 0.017). The combination of dapagliflozin and furosemide significantly increased the risk of acute kidney injury (AKI) at the endpoint ( p = 0.006). Age, gender, and chronic kidney disease status did not significantly influence the occurrence of AKI, hyponatremia, or hyperkalemia ( p &gt; 0.05). These findings emphasize the importance of the close monitoring of renal function and electrolyte balance, particularly in the early stages of dapagliflozin therapy, especially in patients receiving diuretics or renin-angiotensin-aldosterone system inhibitors.

Acute Kidney Injury and Electrolyte Imbalances Caused by Dapagliflozin Short-Term Use.

Pharmaceuticals

Type 2 diabetes mellitus is a chronic disease that is increasing in global prevalence. An individualized approach to pharmacotherapy should consider costs, benefits beyond glucose control, and adverse events. Metformin is the first-line therapy due to its low cost and effectiveness. Sulfonylureas and thiazolidinediones are additional low-cost oral hypoglycemic classes available in the United States; however, evidence shows variability in weight gain and hypoglycemia. Thiazolidinediones increase fluid retention and are not recommended in patients with New York Heart Association class III or IV heart failure. Newer medications, including glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors, have demonstrated weight loss, reduced cardiovascular events, decreased renal disease, and improved all-cause morbidity and mortality. Sodium-glucose cotransporter-2 inhibitors are recommended for people with known cardiovascular disease, heart failure, and chronic kidney disease but carry an increased risk of urinary tract and mycotic infections. Glucagon-like peptide-1 receptor agonists are contraindicated in patients with active multiple endocrine neoplasia type 2 or a personal or family history of medullary thyroid carcinoma; adverse effects include gastrointestinal upset and pancreatitis. Dipeptidyl-peptidase-4 inhibitors have a low risk of hypoglycemia but may increase the risk of pancreatitis and require a renal dose adjustment. Public and private programs to increase access to newer hypoglycemic medications are increasing; however, there are limitations to access, particularly for uninsured and underinsured people.

Management of Type 2 Diabetes Mellitus With Noninsulin Pharmacotherapy.

American Family Physician

1: &#x2002;ESGE recommends cold snare polypectomy (CSP), to include a clear margin of normal tissue (1-2&#x200a;mm) surrounding the polyp, for the removal of diminutive polyps (&#x2264;&#x200a;5&#x200a;mm).Strong recommendation, high quality of evidence. 2: &#x2002;ESGE recommends against the use of cold biopsy forceps excision because of its high rate of incomplete resection.Strong recommendation, moderate quality of evidence. 3: &#x2002;ESGE recommends CSP, to include a clear margin of normal tissue (1-2&#x200a;mm) surrounding the polyp, for the removal of small polyps (6-9&#x200a;mm).Strong recommendation, high quality of evidence. 4: &#x2002;ESGE recommends hot snare polypectomy for the removal of nonpedunculated adenomatous polyps of 10-19&#x200a;mm in size.Strong recommendation, high quality of evidence. 5: &#x2002;ESGE recommends conventional (diathermy-based) endoscopic mucosal resection (EMR) for large (&#x2265;&#x200a;20&#x200a;mm) nonpedunculated adenomatous polyps (LNPCPs).Strong recommendation, high quality of evidence. 6: &#x2002;ESGE suggests that underwater EMR can be considered an alternative to conventional hot EMR for the treatment of adenomatous LNPCPs.Weak recommendation, moderate quality of evidence. 7: &#x2002;Endoscopic submucosal dissection (ESD) may also be suggested as an alternative for removal of LNPCPs of &#x2265;&#x200a;20&#x200a;mm in selected cases and in high-volume centers.Weak recommendation, low quality evidence. 8: &#x2002;ESGE recommends that, after piecemeal EMR of LNPCPs by hot snare, the resection margins should be treated by thermal ablation using snare-tip soft coagulation to prevent adenoma recurrence.Strong recommendation, high quality of evidence. 9: &#x2002;ESGE recommends (piecemeal) cold snare polypectomy or cold EMR for SSLs of all sizes without suspected dysplasia.Strong recommendation, moderate quality of evidence. 10: &#x2002;ESGE recommends prophylactic endoscopic clip closure of the mucosal defect after EMR of LNPCPs in the right colon to reduce to reduce the risk of delayed bleeding.Strong recommendation, high quality of evidence. 11: &#x2002;ESGE recommends that en bloc resection techniques, such as en bloc EMR, ESD, endoscopic intermuscular dissection, endoscopic full-thickness resection, or surgery should be the techniques of choice in cases with suspected superficial invasive carcinoma, which otherwise cannot be removed en bloc by standard polypectomy or EMR.Strong recommendation, moderate quality of evidence.

Colorectal polypectomy and endoscopic mucosal resection: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2024.

Endoscopy

In this comprehensive state-of-the-art review, we provide an evidence-based analysis of current drug therapies for patients with heart failure with preserved ejection fraction (HFpEF) in the acute and chronic phases with concurrent hypertension. Additionally, we explore the latest developments and emerging evidence on the efficacy, safety, and clinical outcomes of common and novel drug treatments in the management of HFpEF with concurrent hypertension. During the acute phase of HFpEF, intravenous diuretics, mineralocorticoid receptor antagonists (MRAs), and vasodilators are pivotal, while in the chronic phase, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers have proven effective in enhancing clinical outcomes. However, the use of calcium channel blockers in HFpEF with hypertension should be approached with caution, owing to their potential negative inotropic effects. We also explored emerging drug therapies for HFpEF, such as sodium-glucose co-transporter 2 (SGLT2) inhibitors, angiotensin receptor-neprilysin inhibitor (ARNI), soluble guanylate cyclase (sGC) stimulators, novel MRAs, and ivabradine. Notably, SGLT2 inhibitors have shown promise in reducing heart failure hospitalizations and cardiovascular mortality in patients with HFpEF, regardless of their diabetic status. Additionally, ARNI and sGC stimulators have demonstrated potential in improving symptoms, functional capacity, and quality of life. Nonetheless, additional research is necessary to pinpoint optimal treatment strategies for HFpEF with concurrent hypertension. Furthermore, long-term studies are essential to assess the durability and sustained benefits of emerging drug therapies. Identification of novel targets and mechanisms underlying HFpEF pathophysiology will pave the way for innovative drug development approaches in the management of HFpEF with concurrent hypertension.

Possible Cause of Nonlinear Tension Rise in Activated Muscle Fiber during Stretching.

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