OBJECTIVETo study the effect of fleroxacin (FLRX) on biological properties of Bloom (BLM) helicase catalytic core (BLM642-1290 helicase) in vitro and the molecular mechanism of interaction between the two molecules.

METHODSDNA-binding and unwinding activities of BLM642-1290 helicase were assayed by fluorescence polarization and gel retardation assay under conditions that the helicase was subjected to different concentrations of FLRX. Effect of FLRX on helicase ATPase activity was analyzed by phosphorus-free assay based on a colorimetric estimation of ATP hydrolysis-produced inorganic phosphate. Molecular mechanism of interaction between the two molecules was assayed by ultraviolet and fluorescence spectra.

RESULTSThe DNA unwinding and ATPase activities of BLM642-1290 helicase were inhibited whereas the DNA-binding activity was promoted in vitro. A BLM-FLRX complex was formed through one binding site, electrostatic and hydrophobic interaction force. Moreover, the intrinsic fluorescence of the helicase was quenched by FLRX as a result of non-radioactive energy transfer. The biological activity of helicase was affected by FLRX, which may be through an allosteric mechanism and stabilization of enzyme conformation in low helicase activity state, disruption of the coupling of ATP hydrolysis to unwinding, and blocking helicase translocation on DNA strands.

CONCLUSIONFLRX may affect the biological activities and conformation of BLM642-1290 helicase, and DNA helicase may be used as a promising drug target for some diseases.

DNA ; metabolism ; Fleroxacin ; pharmacology ; Nucleic Acid Synthesis Inhibitors ; pharmacology ; RecQ Helicases ; antagonists & inhibitors ; metabolism ; Spectrometry, Fluorescence ; Spectrophotometry, Ultraviolet

OBJECTIVETo observe the effect of Shufei Granule (SG) on right ventricular function in patients with chronic pulmonary heart disease (CPHD).

METHODSOne hundred CPHD patients were randomly divided into two groups, the control group (n = 40) treated with fleroxacin 0.2 g twice per day by intravenous dripping and diprophylline 0.2 g 3 times per day orally, the treatment group (n = 60) treated with SG 10 g 3 times a day orally additionally besides the treatment given to the control group. The therapeutic course for both groups was 3 weeks. The changes of the cardiac function, the right ventricular function [A peak velocity (VA), E peak velocity (VE), VA/VE, systolic pulmonary artery pressure (SPAP), pre-ejection period (PEP), right ventricular ejection time (RVET), PEP/RVET], and blood-gas analysis were investigated, the condition of clinical symptoms and signs as well as tongue pictures were observed also.

RESULTSThe total effective rate was 91.6% in the treated group, significantly higher than that in the control group (70.0%, P < 0.01); the improvements in symptom score, cardiac function and the other laboratory indexes were all superior in the treatment group to those in the control group (P < 0.05, P < 0.01).

CONCLUSIONSG is an effective drug for improving right ventricular function in CPHD patients.

Adult ; Aged ; Chronic Disease ; Drug Therapy, Combination ; Drugs, Chinese Herbal ; therapeutic use ; Dyphylline ; therapeutic use ; Female ; Fleroxacin ; therapeutic use ; Humans ; Male ; Middle Aged ; Phytotherapy ; Pulmonary Heart Disease ; drug therapy ; physiopathology ; Ventricular Function, Right ; drug effects