[Correlation between heart rate index, SBPpeak-to-SBPrest ratio and peak oxygen consumption in patients with chronic heart failure].

Objective: To investigate the correlation between heart rate index (HRI), systolic blood pressure(SBP) peak-to-SBPrest ratio (SBPR) and peak oxygen consumption (peakVO2) in patients with chronic heart failure (CHF), and discuss the possibility of using HRI and SBPR collected during exercise to assess the exercise tolerance of CHF patients in the absence of gas analysis. Methods: In this cross-sectional study, a total of 547 patients with CHF who underwent cardiopulmonary exercise test(CPET) in Tongji Hospital Heart Rehabilitation Center Affiliated to Tongji University from March 2007 to December 2018 were collected retrospectively, focusing on their clinical data including age, gender, type of heart failure,BMI as well as data collected during their CPETs, such as peakVO2, HRI and SBPR. Spearman univariate correlation analysis was used for statistical analysis, to unveil the correlations between peakVO2 and those parameters, and multiple linear regression analysis was also conducted. Results: A total of 547 CHF patients conducting CPET were included in this research, of which 447 were male, at age of 63(56, 69). Univariate analysis indicates that HRI, SBPR and peakVO2 showed significant positive correlation (r=0.323, 0.263, respectively, all P<0.001); Age and peak VO2 showed significant negative correlation(r=-0.207, P<0.001); Male patients showed peakVO2 higher than female(r=-0.229, P<0.001); PeakVO2 of heart failure with reduced ejection fraction(HFrEF) was lower than heart failure with mid-range ejection fraction(HFmrEF)and heart failure with preserved ejection fraction(HFpEF) (r=0.181, P<0.001). Body mass index (BMI) had no significant correlation with peakVO2 (P>0.05). Multivariate linear regression analysis showed that the HRI, SBPR were positively correlated with peakVO2(t=7.68, 5.08, respectively, all P<0.05), while age and BMI showed negative correlation with peakVO2(t=-5.43, -0.31, respectively, all P<0.05). PeakVO2 of male was higher than female(t=-6.03, P<0.05), and peakVO2 of HFrEF was lower than those of HFmrEF and HFpEF(t=3.17, 4.48, respectively, all P<0.05). A linear equation (F=33.52, adjusted R2=0.29) could be constructed: peakVO2=10.65(male) or 8.53(female)+4.26HRI+3.31SBPR-0.07age-0.13BMI+0(HFrEF) or 1.05 (HFmrEF) or 1.62(HFpEF). Conclusion: HRI and SBPR are positively correlated with peakVO2. In the absence of gas analysis, it is possible to apply HRI and SBPR during exercise to predict exercise tolerance in patients with CHF.

Molecular cloning and characterization of a short peptidoglycan recognition protein from silkworm Bombyx mori.

Peptidoglycan is the major bacterial component recognized by the insect immune system. Peptidoglycan recognition proteins (PGRPs) are a family of pattern-recognition receptors that recognize peptidoglycans and modulate innate immune responses. Some PGRPs retain N-acetylmuramoyl-L-alanine amidase (Enzyme Commission number: 3.5.1.28) activity to hydrolyse bacterial peptidoglycans. Others have lost the enzymatic activity and work only as immune receptors. They are all important modulators for innate immunity. Here, we report the cloning and functional analysis of PGRP-S4, a short-form PGRP from the domesticated silkworm, Bombyx mori. The PGRP-S4 gene encodes a protein of 199 amino acids with a signal peptide and a PGRP domain. PGRP-S4 was expressed in the fat body, haemocytes and midgut. Its expression level was significantly induced by bacterial challenges in the midgut. The recombinant PGRP-S4 bound bacteria and different peptidoglycans. In addition, it inhibited bacterial growth and hydrolysed an Escherichia coli peptidoglycan in the presence of Zn2+ . Scanning electron microscopy showed that PGRP-S4 disrupted the bacterial cell surface. PGRP-S4 further increased prophenoloxidase activation caused by peptidoglycans. Taken together, our data suggest that B. mori PGRP-S4 has multiple functions in immunity.

Prokaryotical expression of structural and non-structural proteins of hepatitis G virus.

AIM: To study the epitope distribution of hepatitis G virus (HGV) and to seek for the potential recombinant antigens for the development of HGV diagnostic reagents. METHODS: Fourteen clones encompassing HGV gene fragments from core to NS3 and NS5 were constructed using prokaryotic expression vector pRSET and (or) pGEX, and expressed in E.coli. Western blotting and ELISA were used to detect the immunoreactivity of these recombinant proteins. RESULTS: One clone with HGV fragment from core to E1 (G1), one from E2 (G31), three from NS3 (G6, G61, G7), one from NS5B (G821) and one chimeric fragment from NS3 and NS5B (G61-821) could be expressed well and showed obvious immunoreactivity by Western blotting. One clone with HGV framment from NS5B (G82) was also well expressed, but could not show immunoreactivity by Western blotting. No obvious expression was found in the other six clones. All the expressed recombinant proteins were in inclusion body form, except the protein G61 which could be expressed in soluble form. Further purified recombinant proteins G1, G31, G61, G821 and G61-821 were detected in indirected ELISA as coating antigen respectively. Only recombinant G1 could still show immunoreactivity, and the other four recombinant proteins failed to react to the HGV antibody positive sera. Western blotting results indicated that the immunoactivity of these four recombinant proteins were lost during purification. CONCLUSION: Core to E1, E2, NS3 and NS5 fragment of HGV contain antigenic epitopes, which could be produced in prokaryotically expressed recombinant proteins. A high-yield recombinant protein (G1) located in HGV core to E1 could remain its epitope after purification, which showed the potential that G1 could be used as a coating antigen to develop an ELISA kit for HGV specific antibody diagnosis.

cDNA cloning of c33-c antigen gene derived from NS3 region of Chinese HCV genome, expression in Escherichia coli and development of HCV EIA second-generation diagnostic kit.

A cDNA fragment of about 860 bp corresponding to the c33-c gene in the non-structural region 3 (NS3) of HCV genome was obtained from one plasma derived from a Chinese HCV carrier who came from Tai' an of Shandong Province, China by the application of reverse transcription (RT) and polymerase chain reaction (PCR) techniques. After the sequence of the cDNA fragment was determined and compared with the equivalent region of the HCV-I (HCV-US) and HCV-II (HCV-BK) genomes, the nucleotide/amino acid sequence homologies were found to be 79.2%/91.3%/ and 91.3%/93.9%, respectively. The prokaryotic expression vector pBV220 was employed for the overproduction of c33-c native recombinant protein in E. coli cells. The expression products were detected by enzyme-linked immunosorbent assay (ELISA) and Western blotting with antisera of chronic hepatitis C patients, and a molecular weight 31 kD of c33-c viral protein was shown to account for 14% of the total cellular soluble proteins. This product was extracted from the bacterial lysate by lysozyme, Triton X-100 and urea treatment, and purified through ion exchange chromatography. The purified c33-c protein combined with a branch peptide MAP-C-19 representing immunodominant epitopes on the nucleocapsid region of HCV genome was used to develop a Chinese HCV EIA 2nd-generation diagnostic kit for the detection of anti-HCV antibodies. Its specificity, sensitivity and reproducibility were all in keeping with the indexes of the national standard for the quality control of the HCV diagnostic kit. The agreement rate between our kit and Abbott company's HCV EIA second-generation diagnostic kit was 99.33%, and the identified rate of positive anti-HCV of our kit was 2% more than that of the Abbott company's kit.