Research progress and controversy on T wave formation mechanism

Although ECG has been developed for a hundred years, the mechanism of T wave formation is unknown. The proposal of in vitro wedge-shaped model has greatly promoted the understanding of T-wave formation mechanism. By comparing the action potentials of epicardial cells, medial cells and endocardial cells in wedge-shaped ventricular mass with the T wave of body surface ECG, it was found that the T wave was mainly formed by the dispersion of transmural repolarization of ventricular muscle. However, in the subsequent in vivo experiments, electrophysiologists found that the formation of T wave was related to the dispersion of ventricular global repolarization, and the repolarization order of different parts of the three-dimensional global heart determined the polarity of T wave. In the real heart, the mechanism of T wave formation may be more complex, its repolarization gradient may include repolarization in each axis of the heart, and the polarity of T wave may also be the result of multiple factors

Integrated Arthropod Pest Management Systems for Human Health Improvement in Africa

In a sub-Saharan African context, limited natural resources, infectious diseases, including those transmitted by arthropod vectors, and chronic exposure to food contaminated with mycotoxin-producing fungi which, among others, are vectored by insects, are among the major constraints to human health. Thus, pest control should be an important component in human health improvement projects. It appears that the advantages of preventive over curative methods are rarely recognised in Africa, with more emphasis being given to the search for the ‘silver bullet' than to integrated control approaches. Integrated pest management (IPM) systems can be assigned to different decision-making levels as well as to different integration levels, combining ecological (individual pest species, species communities, species assemblages) and management (crop, cropping systems, farms, communities) levels with the respective control systems. These levels produce a highly structured environment for decision-making, in which the use of modern information technology is important. Case studies show that IPM systems are developed and implemented at four integration levels, whereby most work is done on the lowest integration level, addressing a single pest or pest complex attacking a particular crop, group of livestock or human population, and the respective control measures undertaken. Coordinated efforts to develop and implement supplementary IPM systems at higher levels are concluded to be important elements in integrated pest management and a further contribution to human health improvement and poverty alleviatio

Uspostava sendvič ELISE testa za goveđi plazma PON-1 i njegova prediktivna vrijednost za masnu jetru u mliječnih krava

The aim of this study to improve the clinical diagnosis of fatty livers (FL) in dairy cows by using the paraoxonase-1 (PON-1) enzyme as a detection index. Prokaryotic expression technology was used to generate recombinant bovine PON-1 protein. Mice were immunized with this protein to generate hybridoma cells, stably secreting anti-PON-1. Cells were injected into the peritoneal cavity of mice, and ascites were purified to generate bovine PON-1 monoclonal antibody. Rabbits were then immunized with this antigen, and a polyclonal antibody against bovine PON-1 was obtained. Using monoclonal and polyclonal antibodies, a double-antibody sandwich ELISA for plasma PON-1 was constructed. Plasma samples were collected from healthy (n = 13) and FL (n = 13) cows, and plasma PON-1 levels were detected using the PON-1 ELISA. Receiver operating characteristic curve (ROC) analysis was used to analyze correlations between PON-1 levels and FL. Results showed that the ideal working concentration of the monoclonal antibody was 0.8 mg/mL, and the quantitative detection limit was 90 ng/mL. Plasma PON-1 levels were significantly lower in FL cows, when compared with healthy animals. It is concluded that PON-1 ELISA predicts risk factors for dairy cows with FL. PON-1 levels in plasma can be used as an early warning indicator for FL and concentration of 61.87 nmol/L was identified as warning index.Cilj ovog rada bio je unaprijediti kliničku dijagnostiku masne jetre (FL) u mliječnih krava upotrebom enzima paraoksonaze-1 (PON-1) kao indeksa za otkrivanje bolesti. Primijenjena je metoda prokariotske ekspresije kako bi se proizveo rekombinantni goveđi protein PON-1. Miševi su imunizirani ovim proteinom kako bi porizveli stanice hibridoma sa stabilnim izlučivanjem anti-PON-1. Stanice su injektirane u peritonealnu šupljinu miševa te je ascites pročišćen kako bi proizveo goveđa monoklonska protutijela PON-1. Tim su antigenom imunizirani kunići te je dobiveno poliklonsko antitijelo na goveđi PON-1. Upotrebom monoklonskih i poliklonskih antitijela uspostavljen je sendvič ELISA test dva sloja antitijela za plazmatski PON-1. Uzorci plazme prikupljeni su iz zdravih krava (n = 13) i krava s masnom jetrom (n = 13), dok su razine plazmatskog PON-1 detektirane upotrebom PON-1 ELISA. Analizom ROC krivulje analizirane su korelacije između razina PON-1 i FL-a. Rezultati pokazuju da je idealna radna koncentracija monoklonskih protutijela bila 0,8 mg/mL, a kvantitativno ograničenje detekcije 90 ng/mL. Razine plazmatskog PON-1 bile su znakovito niže u krava s masnom jetrom u usporedbi sa zdravim životinjama. Zaključeno je da je PON-1 dobiven ELISA-om prediktor rizičnih čimbenika za masnu jetru u krava. Plazmatske razine PON-1 mogu poslužiti kao rani pokazatelj masne jetre, a kao upozoravajući indeks pokazala se koncentracija od 61,87 nmol/L

Effect of angiotensin receptor neprilysin inhibitors on left atrial remodeling and prognosis in heart failure

Aims The angiotensin receptor–neprilysin inhibitor (ARNI), sacubitril/valsartan, confers additional protective effects compared with angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEIs/ARBs) in terms of reversed left ventricular (LV) remodelling and improves the prognosis of patients with heart failure (HF). However, few studies have examined the effects of ARNI on the left atrium. Accordingly, this study compared the effects of ARNI and ACEI/ARB on left atrial (LA) remodelling in heart failure with reduced ejection fraction (HFrEF). Methods and results This was a single-centre retrospective study of patients with HFrEF hospitalized at the First Affiliated Hospital of Dalian Medical University between 26 February 2016 and 8 July 2020. Patients were classified into ARNI and ACEI/ARB groups and further subgroups based on the left atrial volume index (LAVI): mildly abnormal (29 mL/m2 ≤ LAVI < 34 mL/m2), moderately abnormal (34 mL/m2 ≤ LAVI < 40 mL/m2), and severely abnormal (LAVI ≥ 40 mL/m2). The primary endpoint was changes in LA parameters by echocardiography. The secondary endpoint was all-cause mortality. A total of 336 patients (mean age: 64.11 ± 12.86, 30.06% female) were included. Except those lost to follow-up, 274 HFrEF patients remained, with 144 cases in the ARNI group and 130 cases in the ACEI/ARB group. Greater reductions from baseline were seen with ARNI in LA diameter (LAD) (P = 0.013, t-test), superior and LA superior–inferior diameter (LASID) (P < 0.0001), LA transverse diameter (LATD) (P < 0.0001), LA volume (LAV) (P < 0.0001), LAVI (P < 0.0001), and LA sphericity index (LASI) (P < 0.0001). Over a mean follow-up of 19.40 months, 97 patients (67.3%) in the ARNI group and 29 patients (22.3%) in the ACEI/ARB group showed LA reverse remodelling (LARR). Kaplan–Meier analysis showed significantly lower overall mortality in the ARNI group compared with the ACEI/ARB group (P = 0.048, log-rank test). The mildly abnormal LAVI group of ARNI patients showed a reduction in mortality compared with ACEI/ARB patients (P = 0.044). However, no significant difference was observed for the moderately abnormal (P = 0.571) or severely abnormal LAVI groups (P = 0.609), suggesting that early initiation of ARNI was associated with a better prognosis. Conclusions In this proof-of-concept study, ARNI use showed greater effects on LARR and was associated with a better prognosis compared with ACEI/ARB use in HFrEF. Early initiation of ARNI in the HF disease process may produce greater benefit, but this needs to be confirmed in future studies

Predictive value of HFA-PEFF score in patients with heart failure with preserved ejection fraction

HFA-PEFF score has been proposed for diagnosing heart failure with preserved ejection fraction (HFpEF). Currently, there are only a limited number of tools for predicting the prognosis. In this study, we evaluated whether the HFA-PEFF score can predict mortality in patients with HFpEF. This single-center, retrospective observational study enrolled patients diagnosed with HFpEF at the First Affiliated Hospital of Dalian Medical University between January 1, 2015, and April 30, 2018. The subjects were divided according to their HFA-PEFF score into low (0-2 points), intermediate (3-4 points), and high (5-6 points) score groups. The primary outcome was all-cause mortality. A total of 358 patients (mean age: 70.21 ± 8.64 years, 58.1% female) were included. Of these, 63 (17.6%), 156 (43.6%), and 139 (38.8%) were classified into the low, intermediate, and high score groups, respectively. Over a mean follow-up of 26.9 months, 46 patients (12.8%) died. The percentage of patients who died in the low, intermediate, and high score groups were 1 (1.6%), 18 (11.5%), and 27 (19.4%), respectively. A multivariate Cox regression identified HFA-PEFF score as an independent predictor of all-cause mortality [hazard ratio ( ):1.314, 95% : 1.013-1.705, = 0.039]. A Cox analysis demonstrated a significantly higher rate of mortality in the intermediate ( : 4.912, 95% 1.154-20.907, = 0.031) and high score groups ( : 5.291, 95% : 1.239-22.593, = 0.024) than the low score group. A receiver operating characteristic (ROC) analysis indicated that the HFA-PEFF score can effectively predict all-cause mortality after adjusting for age and New York Heart Association (NYHA) class [area under the curve (AUC) 0.726, 95% 0.651-0.800, = 0.000]. With an HFA-PEFF score cut-off value of 3.5, the sensitivity and specificity were 78.3 and 54.8%, respectively. The AUC on ROC analysis for the biomarker component of the score was similar to that of the total score. The HFA-PEFF score can be used both to diagnose HFpEF and predict the prognosis. The higher scores are associated with higher all-cause mortality. [Abstract copyright: Copyright © 2021 Sun, Si, Li, Dai, King, Zhang, Zhang, Xia, Tse and Liu.

Reverse atrial remodeling in heart failure with recovered ejection fraction

Background Heart failure with recovered ejection fraction (HFrecEF) has been a newly recognized entity since 2020. However, the concept has primarily focused on left ventricular ejection fraction improvement, with less focus on the recovery of the left atrium. In this study, we investigated changes in left atrial (LA) echocardiographic indices in HFrecEF. Methods and Results An inpatient cohort with heart failure with reduced ejection fraction (HFrEF) was identified retrospectively and followed up prospectively in a single tertiary hospital. The enrolled patients were classified into HFrecEF and persistent HFrEF groups. Alternations in LA parameters by echocardiography were calculated. The primary outcome was a composite of cardiovascular death or heart failure rehospitalization. A total of 699 patients were included (HFrecEF: n=228; persistent HFrEF: n=471). Compared with persistent HFrEF, the HFrecEF group had greater reductions in LA diameter, LA transverse diameter, LA superior–inferior diameter, LA volume, and LA volume index but not in LA sphericity index. Cox regression analysis showed that the HFrecEF group experienced lower risks of prespecified end points than the persistent HFrEF group after adjusting for confounders. Additionally, 136 (59.6%) and 62 (13.0%) patients showed LA reverse remodeling (LARR) for the HFrecEF and persistent HFrEF groups, respectively. Among the HFrecEF subgroup, patients with LARR had better prognosis compared with those without LARR. Multivariate logistic analysis demonstrated that age and coronary heart disease were 2 independent negative predictors for LARR. Conclusions In HFrecEF, both left ventricular systolic function and LA structure remodeling were improved. Patients with HFrecEF with LARR had improved clinical outcomes, indicating that the evaluation of LA size provides a useful biomarker for risk stratification of heart failure

Progress of Antarctic meteorite survey and research in China

More than 50000 meteorite samples have been collected in Antarctica since 1969, making meteorite surveys a very important aspect of Antarctic expeditions. The Chinese National Antarctic Research Expedition has collected more than 12000 meteorites in the Grove Mountains region, where has been confirmed as one of the richest meteorite concentration sites in Antarctica. China, therefore, possesses one of the world’s largest Antarctic meteorite collections and has made substantial contributions to this field of research. We summarize here the Chinese meteorite survey efforts in the Grove Mountains, as well as discuss progress of the classification and investigation of Grove Mountains meteorites. Outlooks are also proposed for the future of Antarctic meteorite work