Objective To analyze the occurrence status of low blood pressure (BP) in patients with refractory heart failure (RHF) and its relationship with comorbidities. Methods A retrospective analysis was conducted on the clinical data of 360 patients with RHF who were hospitalized in department of cardiology of Affiliated Nantong Hospital of Shanghai University from May 2021 to May 2025. These patients were divided into the RHF with BP group and the RHF group based on their blood pressure at admission. The general data and comorbidities were compared between both groups. Multivariate logistic regression analysis was used to identify the risk factors for coexisting BP. Results The heart rate (HR), N-terminal pro-B-type natriuretic peptide (NT-proBNP), blood urea nitrogen, high-sensitivity cardiac troponin T, right atrial diameter, proportion of cardiac function grade IV, use rate of diuretics and prevalence rate of dilated cardiomyopathy (DCM) in the RHF with BP group were higher while the high-density lipoprotein cholesterol (HDL-C), albumin, left ventricular ejection fraction, use rate of lipid-lowering drugs and prevalence rate of coronary heart disease were lower compared to the RHF group, and the differences were statistically significant (P<0.05). Multivariate logistic regression analysis suggested that increased HR (OR=1.685, 95%CI: 1.106-2.569), increased NT-proBNP (OR=1.772, 95%CI: 1.138-2.759), decreased HDL-C (OR=0.605, 95%CI: 0.400-0.917) and DCM (OR=1.956, 95%CI: 1.176-3.255) were independent risk factors affecting BP in RHF patients (P<0.05). Conclusion The incidence rate of low blood pressure in elderly RHF patients is about 19.17%. Increased heart rate, increased NT-proBNP, decreased HDL-C and dilated cardiomyopathy are closely linked to the occurrence of low blood pressure, and they can be used as clinically related factors to identify patients at high risk of low blood pressure.

OBJECTIVETo investigate the in vitro killing efficiency of D-amino acid oxidase (DAAO)/D-alanine (D-Ala) system on K562e cells.

METHODSK(DfGC) cell line stably expressing DAAO was obtained by retrovirus transfection technique. The integration and expression of DAAO gene were identified by PCR and in situ hybridization. The killing activities of D-Ala to DAAO(+) cells alone or the mixtures of DAAO(+) and DAAO(-) cells in different ratios were observed. H(2)O(2) production by K(DfGC) cell was measured by phenol red oxidation assay.

RESULTSPCR and in situ hybridization analysis confirmed the integration of DAAO gene in positive clone and its mRNA expression. There was no significant difference in cell proliferation between the two kinds of K562 cells. Ninety percent of K(DfGC) cells was killed by 12.5 mmol/L D-Ala after 24 hour-treatment and the H(2)O(2) levels were in accord with the killing activities of D-Ala. When K(DfGC) was mixed with K562e at different ratio, no significant bystander effect could be found after treating with 15.0 mmol/L D-Ala for 24 hours.

CONCLUSIONThe leukemia cell line K562e was sensitive to DAAO/D-Ala system and there was no significant bystander effects observed within this cells.

Alanine ; metabolism ; pharmacology ; Cell Survival ; drug effects ; D-Amino-Acid Oxidase ; genetics ; metabolism ; Gene Expression ; Humans ; Hydrogen Peroxide ; metabolism ; K562 Cells ; cytology ; drug effects ; metabolism ; Plasmids ; genetics ; RNA, Messenger ; genetics ; metabolism ; Transfection