A novel cost function to estimate parameters of oscillatory biochemical systems

Oscillatory pathways are among the most important classes of biochemical systems with examples ranging from circadian rhythms and cell cycle maintenance. Mathematical modeling of these highly interconnected biochemical networks is needed to meet numerous objectives such as investigating, predicting and controlling the dynamics of these systems. Identifying the kinetic rate parameters is essential for fully modeling these and other biological processes. These kinetic parameters, however, are not usually available from measurements and most of them have to be estimated by parameter fitting techniques. One of the issues with estimating kinetic parameters in oscillatory systems is the irregularities in the least square (LS) cost function surface used to estimate these parameters, which is caused by the periodicity of the measurements. These irregularities result in numerous local minima, which limit the performance of even some of the most robust global optimization algorithms. We proposed a parameter estimation framework to address these issues that integrates temporal information with periodic information embedded in the measurements used to estimate these parameters. This periodic information is used to build a proposed cost function with better surface properties leading to fewer local minima and better performance of global optimization algorithms. We verified for three oscillatory biochemical systems that our proposed cost function results in an increased ability to estimate accurate kinetic parameters as compared to the traditional LS cost function. We combine this cost function with an improved noise removal approach that leverages periodic characteristics embedded in the measurements to effectively reduce noise. The results provide strong evidence on the efficacy of this noise removal approach over the previous commonly used wavelet hard-thresholding noise removal methods. This proposed optimization framework results in more accurate kinetic parameters that will eventually lead to biochemical models that are more precise, predictable, and controllable

Pulsed-field ablation of atrial fibrillation with a pentaspline catheter across National Health Service England centres.

INTRODUCTION: Pulsed-field ablation (PFA) is a novel modality for pulmonary vein isolation in patients with atrial fibrillation (AF). We describe the initial uptake and experience of PFA using a pentaspline catheter across selected National Health Service England (NHSE) centres. METHODS: Data collected by NHSE Specialised Services Development Programme regarding AF ablation procedures using a single-shot, pentaspline, multielectrode PFA catheter (FARAWAVE, Boston Scientific) between June 2022 and August 2024 were aggregated and analysed to examine procedural metrics, acute efficacy and safety outcomes over 3-month follow-up. RESULTS: 1034 procedures were submitted. The patients were 32.1% female, mean age 63.8±10.7 years, 53.1% paroxysmal AF and 89.7% first-time AF ablation. Procedures were performed by 48 consultant operators at nine NHSE centres, with a mean of 115 procedures per centre (range 25-264). 93.7% of procedures were performed under general anaesthesia. Median skin-to-skin procedure time was 74 min (IQR 55-96 min) and fluoroscopy time 20 min (IQR 15-27 min). Electroanatomical mapping was used in 15.3%. In first-time ablation cases, acute isolation of all pulmonary veins was achieved in 99.5% of patients. Left atrial (LA) posterior wall ablation using the PFA catheter was performed in 11.0% of cases; additional LA radiofrequency ablation was performed in 0.6%. The major and minor acute procedural complication rates were, respectively, 1.3% and 3.1%, with no reports of periprocedural death or atrio-oesophageal fistula. 63.8% of patients were discharged on the day of procedure. Follow-up data were available for 870 procedures (84.1%). In the 3 months following ablation, hospitalisation for arrhythmia occurred in 3.2%, with 0.9% rehospitalised for procedural-related complications. CONCLUSION: In this real-world, nationwide registry of a pentaspline PFA catheter, efficacy, safety and efficiency outcomes were comparable to those from previous PFA studies in patients with AF

Effect of garlic on cardiovascular disorders: a review

Garlic and its preparations have been widely recognized as agents for prevention and treatment of cardiovascular and other metabolic diseases, atherosclerosis, hyperlipidemia, thrombosis, hypertension and diabetes. Effectiveness of garlic in cardiovascular diseases was more encouraging in experimental studies, which prompted several clinical trials. Though many clinical trials showed a positive effect of garlic on almost all cardiovascular conditions mentioned above, however a number of negative studies have recently cast doubt on the efficary of garlic specially its cholesterol lowering effect of garlic. It is a great challenge for scientists all over the world to make a proper use of garlic and enjoy its maximum beneficial effect as it is the cheapest way to prevent cardiovascular disease. This review has attempted to make a bridge the gap between experimental and clinical study and to discuss the possible mechanisms of such therapeutic actions of garlic