[Analysis on the sequence mutation and evolution of HBV genome in China].

Objective: To understand immune escape mutation, drug resistance mutation, and genome evolution information of HBV genome sequence in China. Methods: The whole genome sequence information of HBV in China submitted in GenBank from 1998 to 2021 was selected as the object for analysis. MAFFT method was used for cluster analysis. Analysis of immune escape and drug-resistant mutations was performed using the online tool Gen2pheno. The BEAST 1.10.4 was used for analysis the time evolution of HBV sequences. Results: A total of 5 426 sequences were included in the dataset and distributed in 19 provinces of China. Type C accounted for the highest proportion (59.1%, 3 211/5 426), followed by type B (33.7%, 1 833/5 426). Immune escape mutations were found in 764 sequences (14.1%, 764/5 426). At least one reverse transcriptase region mutation occurred in 98.1% of the sequences. The evolutionary roots of most HBV sequences in China date from around 1801 AD. Conclusion: HBV-resistant mutation rate is high in China. HBV genomes evolve slowly.

[Analysis on the hemagglutinin genetic characteristic of 7 measles virus isolated in Henan Province in 2017].

Objective: Analyze the genetic characteristic of Hemagglutinin(H) gene of measles viruses isolated in Henan Province in 2017. Methods: Swab samples collected from 7 lab confirmed measles cases, and we got the measles virus by Vero/Slam inoculation. Fragment of H genes were amplified by reverse transcription polymerase chain reaction(RT-PCR), then the PCR products were sequenced and analyzed. Results: The age of the 7 measles confirmed cases were between 1 and 50 years old, and all of them were males. All the 7 measles viruses were identified as H1a genotype, and the average distance of the nucleotides and the amino acids was 0.005, respectively. Compared with the Shanghai-191/China-vaccine, there were some changes in isolated virus, such as 240(th), 397(th) and 381(st) sites in the amino acid sequence. Conclusion: The measles genotype which isolated in Henan Province in 2017 was H1a. There were some difference from Shanghai-191/China-vaccine in the nucleotides sequence of H gene, which suggested that it's necessary to strengthen the monitor the variation of measles virus.

[Screening for precursors of colorectal cancer].

Screening has been proven to be effective for the control of colorectal cancer (CRC). The target of CRC screening is shifting from CRC to colorectal neoplasia (CN), the precursors of CRC. Based on the the latest national guideline, the Consensus of Screening for CRC and CN, and the recent research of precursors both at home and abroad. This paper summarizes the progress in the research of risk factors, risk prediction model, screening strategy optimization, colonoscopy quality control, sessile serrated adenoma identification and follow up as well as the recognition of precursors.

[Effects of Huanglian ointment on wound healing of mice with full-thickness skin defect and the related mechanism].

Objective: To observe the effects of Huanglian ointment on wound healing of mice with full-thickness skin defect, and to explore the related mechanism. Methods: Thirty male C57BL/6J mice were divided into Huanglian ointment group and vehicle group according to the random number table after round wounds of full-thickness skin defect with diameter of 7.5 mm were inflicted on the back of each mouse, with 15 mice in each group. Wounds of mice in Huanglian ointment group and vehicle group were treated with Huanglian ointment and vehicle respectively from post injury day (PID) 1 on, 2 times each day. Five mice from each group were selected to observe wound changes on PID 0, 3, 7, 10, and 14, and wound healing rates were calculated. Five mice out of the 10 mice that hadn't been used for general observation in each group were sacrificed on PID 3 and 7 respectively, and 5 mice after being used for general observation in each group were sacrificed on PID 14. Wound and skin tissue within 2 mm from the edge of wound was collected. Histologic scoring was conducted based on the histomorphological observation with HE staining. The expression of double positive cells of alpha smooth muscle actin (α-SMA) and Ki-67 (myofibroblast) in tissue of wounds of mice was observed by immunofluorescence staining. Protein expressions of transforming growth factor beta (TGF-ß) and collagen in tissue of wounds of mice were determined by enzyme-linked immunosorbent assay. Data were processed with analysis of variance for repeated measurement, analysis of variance of factorial design, t test of two independent samples, one-way analysis of variance, and Bonferronni test or correction. Results: (1) Wounds of mice in two groups were red and swollen on PID 0, while they were neither red nor swollen with scabs on PID 3 and 7. On PID 10, woundsof mice in Huanglian ointment group contracted obviously, while the contracted wounds of mice in vehicle group were smaller than those in Huanglian ointment group. On PID 14, wounds of most mice in Huanglian ointment group were healed, while wounds of some mice in vehicle group failed to heal. Wound healing rates of mice in two groups were close on PID 3 and 7 (with t values respectively 0.64 and 1.90, P values above 0.05). Wound healing rates of mice in Huanglian ointment group on PID 10 and 14 were (76±7)% and (93±5)% respectively, significantly higher than those of vehicle group [(48±9)% and (68±11)%, with t values respectively 7.44 and 3.89, P values below 0.01]. Wound healing rates of mice in two groups on PID 7, 10, and 14 were significantly higher than those on the previous time points of the same group (with P values below 0.01). (2) Histologic scores of wounds of mice in two groups were close on PID 3 (t=-0.76, P>0.05). Histologic scores of wounds of mice in Huanglian ointment group on PID 7 and 14 were (7.0±1.6) and (11.6±2.1) points respectively, significantly higher than those of vehicle group [(4.2±1.3) and (7.2±1.3) points, with t values respectively 1.96 and 2.50, P<0.05 or P<0.01]. Histologic scores of wounds of mice in two groups on PID 7 and 14 were significantly higher than those on the previous time points of the same group (with P values below 0.01). (3) Percentages of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice in Huanglian ointment group on PID 3 and 7 were (35±12)% and (62±10)% respectively, significantly higher than those of vehicle group [(17±12)% and (34±6)%, with t values respectively -2.48 and -5.25, P<0.05 or P<0.01]. The percentage of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice in Huanglian ointment group on PID 14 was (25±5)%, significantly lower than that of vehicle group [(44±17)%, t=2.50, P<0.05]. The percentage of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice on PID 7 was significantly higher than that on PID 3 or 14 in Huanglian ointment group (with P values below 0.01). Percentages of double positive cells of α-SMA and Ki-67 in tissue of wounds of mice on PID 7 and 14 were significantly higher than those on the previous time points in vehicle group (with P values below 0.05). (4) Protein expressions of TGF-ß in tissue of wounds of mice in Huanglian ointment group on PID 3 and 7 were (396±45) and (722±96) pg/mL respectively, significantly higher than those of vehicle group [(290±42) and (382±62) pg/mL, with t values respectively -8.17 and -6.65, P values below 0.01]. Protein expressions of TGF-ß in tissue of wounds of mice in two groups were close on PID 14 (t=1.60, P>0.05). The protein expression of TGF-ß in tissue of wounds of mice in Huanglian ointment group on PID 7 was significantly higher than that on PID 3 or 14 (with P values below 0.01). Protein expressions of TGF-ß in tissue of wounds of mice in vehicle group on PID 7 and 14 were significantly higher than those on the previous time points (with P values below 0.05). Protein expressions of collagen in tissue of wounds of mice in two groups were close on PID 3 (t=1.99, P>0.05). Protein expressions of collagen in tissue of wounds of mice in Huanglian ointment on PID 7 and 14 were (47±10) and (70±14) ng/mL respectively, significantly higher than those of vehicle group [(34±10) and (42±12) ng/mL, with t values respectively 3.15 and 3.52, P<0.05 or P<0.01]. Protein expressions of collagen in tissue of wounds of mice in two groups on PID 7 and 14 were significantly higher than those on the previous time points of the same group (P<0.05 or P<0.01). Conclusions: Huanglian ointment can promote wound healing of full-thickness skin defect of mice through increasing production of myofibroblasts and protein expressions of TGF-ß and collagen.

[Research Progress of Carrion-breeding Phorid Flies for Post-mortem Interval Estimation in Forensic Medicine].

It is a difficult problem of forensic medicine to accurately estimate the post-mortem interval. Entomological approach has been regarded as an effective way to estimate the post-mortem interval. The developmental biology of carrion-breeding flies has an important position at the post-mortem interval estimation. Phorid flies are tiny and occur as the main or even the only insect evidence in relatively enclosed environments. This paper reviews the research progress of carrion-breeding phorid flies for estimating post-mortem interval in forensic medicine which includes their roles, species identification and age determination of immatures.

Development of human single-chain antibodies against SARS-associated coronavirus.

The outbreak of severe acute respiratory syndrome (SARS), caused by a distinct coronavirus, in 2003 greatly threatened public health in China, Southeast Asia as well as North America. Over 1,000 patients died of the SARS virus, representing 10% of infected people. Like other coronaviruses, the SARS virus also utilizes a surface glycoprotein, namely the spike protein, to infect host cells. The spike protein of SARS virus consists of 1,255 amino acid residues and can be divided into two sub-domains, S1 and S2. The S1 domain mediates the binding of the virus to its receptor angiotensin-converting enzyme 2, which is abundantly distributed on the surface of human lung cells. The S2 domain mediates membrane fusion between the virus and the host cell. Hence two strategies can be used to block the infection of the SARS virus, either by interfering with the binding of the S1 domain to the receptor or by blocking the fusion of the virus with the cell membrane mediated by the S2 domain. Several antibodies against the S1 domain have been generated and all of them are able to neutralize the virus in vitro and in vivo using animal models. Unfortunately, point mutations have been identified in the S1 domain, so that the virus isolated in the future may not be recognized by these antibodies. As no mutation has been found in the S2 domain indicating that this region is more conserved than the S1 domain, it may be a better target for antibody binding. After predicting the immunogenicity of the epitopes of the S2 domain, we chemically synthesized two peptides and also expressed one of them using a recombinant DNA method. We screened a phage displaying library of human single-chain antibodies (ScFv) against the predicted epitopes and obtained a human ScFv which can recognize the SARS virus in vitro.

The expression of human alpha -like globin genes in transgenic mice mediated by bacterial artificial chromosome.

After screening a bacterial artificial chromosome of human genomic DNA library with human HS-40, zeta-, alpha-, and theta-globin probes, a 110-kb clone bearing the whole human alpha-globin gene cluster was obtained and rare restriction endonuclease mapping was performed. The bacterial artificial chromosome DNA was isolated, and transgenic mice were generated. Three founders were detected from 35 newborn mice. The copy numbers were 1, 2, and 2, and the expression of human alpha-globin genes in various tissues at different developmental stages in the transgenic mice was assayed. The human alpha-globin mRNA can be detected in bone marrow, kidney, liver, brain, but not in muscle, testis, or thymus. The human zeta-globin genes were switched off, and the alpha-globin genes were switched at day 11.5 in mouse embryo, indicating that developmental stage-specific expression of the alpha-like globin genes was properly regulated. The human alpha-globin mRNA ranged between 17-68% of the endogenous mouse alpha-globin, suggesting that the expression of human alpha-globin genes is integration site-dependent in transgenic mice. The ratio of human alpha(2)- and alpha(1)-globin gene expression in adult transgenic mouse is about 2.5:1 similar to the expression in human.

Fluorimetry determination of trace Ce3+ with EDTP.

The use of ethylenediaminetetrakis(methylphosphonic) acid (EDTP) in the fluorimetry determination of trace amounts of Ce3+ ions is described. The fluorescence intensity of Ce3+ was greatly enhanced when an 1:1 complex with EDTP in solution of pH 7-8 formed. The apparent excitation and emission wavelength used were 313 and 397 nm, respectively. The fluorescence intensity varied linearly with the concentration of Ce3+ in the range of 1 x 10(-8) -1 x 10(-4) mol l(-1). The quenching effects of coexist ions (other rare earth ions, Fe3+ and some inorganic anions) were studied. This technique has unique advantage in eliminating disturb of coexist.

Proper developmental control of human globin genes reproduced by transgenic mice containing a 160-kb BAC carrying the human beta-globin locus.

Four independent bacterial artificial chromosome (BAC) clones containing the human Beta-globin gene locus were obtained from a human genomic BAC library. A 160-kb clone (186D7) carrying the entire human Beta-globin locus including the Beta-globin gene family, locus control region (LCR), and 3' regulatory elements was used to transform mice. Four transgenic lines were generated by microinjecting the purified BAC DNA into the fertilized eggs. RNase protection analysis showed that the expression of human Beta-globin genes is tissue- and developmental stage-specific and the expression level is similar among the three independent transgenic lines which carry the entire human Beta-globin locus; however, no Beta-globin gene expression was detected in the transgenic mice lacking the LCR region. The results suggest that the transgenic mouse model system that we have produced and that uses BAC to study the complex human Beta-globin gene cluster is stable and reproducible. Our results also indicate that some newly characterized HSs upstream from the LCR appear not to play an important role in globin gene expression and switching, while the traditional LCR can ensure correct human Beta-globin gene expression in transgenic mice. The BAC-mediated transgenic system can be used for further studies to determine which kinds of cis-acting elements are included in regulating the developmental timing and the level of human Beta-globin gene expression.

Transesophageal low-energy cardioversion in an animal model of life-threatening tachyarrhythmias.

The purpose of this study was to determine the feasibility and efficacy of terminating life-threatening ventricular tachyarrhythmia by low-energy synchronous or asynchronous shocks delivered through a transesophageal catheter that had both an anode and a cathode. Forty-three episodes of ventricular fibrillation or flutter (Vf or VF) were provoked by transesophageal asynchronous random shocks occurring during the vulnerable period of the ventricular cycle in seven dogs and seven pigs that were healthy adults. The 43 episodes of Vf or VF were terminated by the transesophageal technique. The defibrillation energy thresholds were 23.11 +/- 6.28 J (range, 5-30 J). Seven episodes of ventricular tachycardia (VT) with a cycle length of 360 msec or less (330 +/- 27 msec) were provoked by ventricular pacing stimuli during acute myocardial ischemia resulting from delayed resuscitation in two dogs and three pigs. Five of the seven VTs had a duration of 31 seconds or more, and they were all terminated by transesophageal synchronous shocks, the cardioversion thresholds being 1.71 +/- 2.25 J (range, 0.25-5 J). Fourteen episodes of idioventricular tachycardia (IVT) with a cycle length of 400 msec or more (445 +/- 33.5 msec) spontaneously occurred after the use of adrenaline and after defibrillation in four dogs and five pigs. We also succeeded in terminating seven episodes of IVT with a duration of 34 seconds or more by the same means of treating VT, although IVT is not an indication for cardioversion in the clinical setting.(ABSTRACT TRUNCATED AT 250 WORDS)

[Survey of birth defects in Huixian].

A survey of births defects was made of 8,721 babies born in Huixian from May 1983 to January 1988. We identified 27 kinds of different physical defects and found 168 cases with congenital malformations (19.26%), slightly high on were defects related to nervous, gastrointestinal, locomotor and skin system. Incidence of physical defects among foetus and still births was evident higher than among live births. Among all the cases, the sex ratio was 1:106: incidence of birth defects was higher in mountainous areas than in the plain, and much lower in the first quarter of the year than in any other. Meanwhile, 28 suspected causative factors were further investigated and it was found that the incidence of birth defects was related to a history of birth defects of mental retardation of parents, certain illness during pregnancy and the intake of certain drugs during mother's pregnancy.