[Analysis on the secondary attack rates of SARS-CoV-2 Omicron variant and the associated factors]

Objective: To evaluate the secondary attack rates of the SARS-CoV-2 Omicron variant and the associated factors. Methods: A total of 328 primary cases and 40 146 close contacts of the SARS-CoV-2 Omicron variant routinely detected in local areas of Jiangsu Province from February to April 2022 were selected in this study, and those with positive nucleic acid test results during 7 days of centralized isolation medical observation were defined as secondary cases. The demographic information and clinical characteristics were collected, and the secondary attack rate (SAR) and the associated factors were analyzed by using a multivariate logistic regression model. Results: A total of 1 285 secondary cases of close contacts were reported from 328 primary cases, with a SAR of 3.2% (95%CI: 3.0%-3.4%). Among the 328 primary cases, males accounted for 61.9% (203 cases), with the median age (Q1, Q3) of 38.5 (27, 51) years old. Among the 1 285 secondary cases, males accounted for 59.1% (759 cases), with the median age (Q1, Q3) of 34 (17, 52) years old. The multivariate logistic regression model showed that the higher SAR was observed in the primary male cases (OR=1.632, 95%CI: 1.418-1.877), younger than 20 years old (OR=1.766, 95%CI: 1.506-2.072),≥60 years old (OR=1.869, 95%CI: 1.476-2.365), infected with the BA.2 strain branch (OR=2.906, 95%CI: 2.388-3.537), the confirmed common cases (OR=2.572, 95%CI: 2.036-3.249), and confirmed mild cases (OR=1.717, 95%CI: 1.486-1.985). Meanwhile, the higher SAR was observed in the close contacts younger than 20 years old (OR=2.604, 95%CI: 2.250-3.015),≥60 years old (OR=1.287, 95%CI: 1.052-1.573) and exposure for co-residence (OR=27.854, 95%CI: 23.470-33.057). Conclusion: The sex and age of the primary case of the Omicron variant, the branch of the infected strain, case severity of the primary case, as well as the age and contact mode of close contacts are the associated factors of SAR.

[A conceptual framework for dynamics of cccDNA in hepatitis B virus]

The resolution of the hepatitis C issue has raised expectations for a chronic hepatitis B cure, driving the industry to expand investment in research and development efforts to strengthen functional cure strategies. These strategies have a wide variety of types, and the published research findings are heterogeneous. The theoretical analysis of these strategies is of great significance for determining prioritized research orientations as well as sensibly allocating research and development resources. However, due to a paucity of necessary conceptual models, current theoretical analysis has not been able to unify various therapeutic strategies into a proper theoretical framework. In view of the fact that the decrease in the quantity of cccDNA is an inevitable core event accompanied by the process of functional cure, this paper intends to analyze several chronic hepatitis B cure strategies using cccDNA dynamics as a framework. Furthermore, there are currently few studies on the dynamics of the cccDNA field, hoping that this article can promote recognition and research in this field.

[The value of preservation of subvalvular structures in patients with mitral and aortic valve replacement surgery and its effect on left ventricular contractility]

Objective: To discuss the clinical value of preserving subvalvular structure in mitral and aortic valve replacement surgery and its effect on left ventricular contractility. Methods: A total of 97 patients who underwent mitral valve replacement surgery in the Adult Cardiac Surgery of Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital from June 2016 to December 2018 were selected as the research subjects, of whom 45 cases were preserved subvalvular structure and 52 cases were in the total resection group (intraoperative total resection of the mitral valve and subvalvular chordae tendineae). General cardiac function indexes and left ventricular function quantitative indexes were compared before and in 3 months and 6 months after the operation of the two groups; The changes of the overall longitudinal strain of the long axis of the apex and the overall circumferential strain of the short axis of the left ventricle determined by the two-dimensional speckle tracking technology were compared before and after the operation. Results: The ages of the patients in the preservation group and the total resection group were (41.8±11.3) and (43.3±10.6) years old, respectively, and the male proportions were 58.0% (26 cases) and 44.0% (23 cases), respectively, with no significant difference (all P>0.05). The aortic occlusion time and cardiopulmonary bypass time of the patients in the preservation group were (57.8±4.5) and (78.6±6.7) min, respectively, which were longer than those in the total resection group [(48.1±4.4) and (48.1±4.4) min, respectively] (all P<0.05). The left atrial pressure of the patients in the preservation group at shutdown was (8.4±1.8) mmHg (1 mmHg=0.133 kPa), which was lower than that of the total resection group (11.3±2.5) mmHg (P<0.001). There were interaction effects between groups and time in regards to the left ventricular end-diastolic diameter ( LVEDD ), left ventricular ejection fraction ( LVEF ) and Tei index, as well as the strain rate of mitral annulus and left ventricular wall of interventricular septum of the preservation group and the total resection group (all P<0.05). LVEDD and LVEF of patients in the preservation group at 3rd month after operation were (44.7±4.0) mm and (45.5±4.2) mm, and at 6th months were (56.5±4.9)% and (58.8±5.0)%, respectively, all larger than (42.7±3.6) mm and (42.7±3.6) mm, (54.5±4.6)% and (56.3±4.8)% of the total resection group. The measured value of LVESD in the preservation group at 3rd month after surgery was (32.6±3.2) mm, which was greater than that in the total resection group (31.2±3.4) mm (P<0.05). The Tei index of patients in the preservation group at 3rd and 6th months after surgery were 1.0±0.2 and 0.8±0.2, respectively, which were lower than those in the total resection group 1.2±0.3 and 0.9±0.2 (all P<0.05). Conclusion: Preserving the subvalvular structure during mitral valve replacement surgery can better improve the patient's left ventricular function and left ventricular systolic capacity.

[Immunogenicity and safety of a booster vaccination with an inactivated severe acute respiratory syndrome coronavirus 2 vaccine in adults aged 18 to 59 years]

Objective: To assess the immunogenicity and safety of a booster vaccination with an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. Methods: The phase Ⅱ trial of an inactivated SARS-CoV-2 vaccine was conducted by Jiangsu Provincial Center for Disease Control and Prevention (CDC) since October 2020. The subjects were healthy adults aged 18-59 years, excluding pregnant, and not breastfeeding women. The primary vaccination schedule groups were 0-14 d 5 μg, 0-14 d 10 μg, 0-28 d 5 μg and 0-28 d 10 μg, respectively. And 50 participants in each group, a total of 200, who have received 2-doses primary vaccination were selected in ascending order of the study number and vaccinated with a booster dose (same dosage as primary vaccination) at the 6th months after post the primary vaccination (30-day window period). Blood samples were collected before and after boosting and tested for the geometric mean titers (GMT) and seroconversion of live virus neutralizing antibody, pseudovirus neutralizing antibody and receptor-binding-domain (RBD) IgG antibody. Adverse events (AE) were collected and assessed within 28 days after boosting. Results: The ages of subjects in group 0-14 d 5 μg, 0-14 d 10 μg, 0-28 d 5 μg and 0-28 d 10 μg were (43.98±9.58), (43.46±9.34), (42.56±9.08) and (43.94±11.05) years old, respectively (P=0.877). Sex ratios were balanced among the 4 groups (P=0.331). The live virus neutralizing antibody GMT (95%CI) in group 0-14 d 5 μg, 0-14 d 10 μg, 0-28 d 5 μg and 0-28 d 10 μg increased from 4.07 (3.30-5.04), 3.75 (3.08-4.55), 8.33 (7.01-11.11) and 7.69 (6.19-9.57) before the booster vaccination to 284.84 (215.28-376.86), 233.05 (178.61-304.08), 274.81 (223.64-337.68) and 280.77 (234.59-336.04) in 28 days after the booster vaccination, respectively. The rates of live virus neutralizing antibody seroconversion were all 100% in the 4 groups. The AE incidences following booster vaccination were 18.0% (9 cases), 4.0% (2 cases), 12% (6 cases), and 12% (6 cases) in the 4 groups(P=0.182). No AE was graded as level 3 or worse. No serious AE was reported. Conclusion: One booster vaccination of an inactivated SARS-CoV-2 vaccine administered 6 months after primary vaccination showed good immunogenicity and safety.

[Construction of urban scale-free network model and its epidemiological significance in the prevention and control of COVID-19]

COVID-19 is a public health emergency currently. In this study, a scale-free network model is established based on the Spring Migration data in 2020.The cities is clustered into three different modules. The epidemic of the cities in the black module was the most serious, followed by the red and the cyan. The black module contains 9 cities in Zhejiang province and 8 cities in Guangdong province, most of them located in the southeast coastal economic belt. These cities should be the key cities for epidemic prevention and control.

[Efficacy and safety of low-intensity pulsed ultrasound at different intervals by mechanical force in treating erectile dysfunction: a preliminary study]

Objective: To study the efficacy and safety of low-intensity pulsed ultrasound (LIPUS) at different intervals by mechanical force in treating erectile dysfunction (ED). Method: Forty patients with mild to moderate ED were randomized in a 1∶1 ratio to receive 16-treatment sessions of LIPUS in group A and group B, applied 3 times per week and 2 times per week, respectively. End-point assessments were made at 8th week after treatment. Efficacy were evaluated using International Index of Erectile Function-Erectile Function domain score (IIEF-EF), Erectile Hardness Score (EHS), Self-Esteem and Relationship Questionnaire (SEAR), Sexual Encounter Profile (SEP), Global Assessment Question (GAQ), and pain were assessed by Visual Analogue Score (VAS).Treatment response was confirmed by a minimal clinically importance difference (MCID) at 8th week. Results: Compared with baseline, IIEF-EF score [(17.1±5.48 vs 23.4±3.75, P<0.05) and (18.9±4.34 vs 24.1±4.32, P<0.05)], proportion of EHS 4 [(0 vs 40%, P<0.05) and (16.7% vs 55.6%, P<0.05)], and Overall Relationship score [(50.6 vs 67.5, P<0.05) and (44.4 vs 70.1, P<0.05)] were significantly improved at 8th week in two groups, respectively. Compared with baseline, the positive responses to SEP-3 increased significantly at 8th week in two groups (50.0% vs 80.0%,P<0.05) and (44.4% vs 88.9%, P<0.05), respectively. The positive responses to GAQ-2 were 90.0% and 88.9% at 8th week in two groups, respectively. There were no significant differences in IIEF-EF, EHS, SEAR, SEP and GAQ at 8th week between two groups. There was no significant difference in treatment response using MCID between two groups at end-point (80.5% vs 77.5%). The treatment duration for full sessions were 2.5 weeks less in group A than group B. No adverse effects were reported in all cases. Conclusion: LIPUS at two different intervals is effective and safe for mild to moderate ED, and the regimen at 3 times per week can achieve quite good effect in relatively short duration,while the long-term effects is still be clarified in further study.

[Effect of omeprazole on plasma concentration and adverse reactions of capecitabine in patients with colon cancer]

Objective: To investigate the effect of omeprazole on plasma concentration, efficacy and adverse reactions of capecitabine in patients with colon cancer. Methods: Seventy-two patients with colon cancer treated with capecitabine were analysed retrospective. The patients treated with capecitabine combined with omeprazole were identified as experimental group and the capecitabine treatment alone as control group.The differences of blood concentration and the side effects of capecitabine between these two groups were compared. Results: The plasma concentration of 5-Fluorouracilum in experimental group was (126.25±50.59) μg/ml, without significant difference of (123.09±56.70) μg/ml in control group (P=0.121). The incidence of Ⅲ to Ⅳ degree bone marrow suppression, nausea, vomiting, diarrhea and hand-foot syndrome in experimental group were 13.8%, 0%, 0% and 19.4%, respectively. In control group, the incidence of Ⅲ to Ⅳ degree bone marrow suppression, nausea, vomiting, diarrhea and the hand-foot syndrome were 11.1%, 0%, 0% and 19.4%, respectively, without significant difference of experimental group (P>0.05). The incidence of acid reflux and heartburn in the control group was 72.2%, significantly higher than 44.4% of the experimental group (P<0.05). The objective response rate (ORR) and progression-free survival time (PFS) in these two groups were 30.6% and 33.3%, and 8.0 month and 8.5 month, respectively, without significant difference (P>0.05). Conclusion: The intravenous omeprazole attenuates reflux and heartburn of colon cancer patients treated with capecitabine, without affecting its plasma concentration and side effects and has no impact on the PFS of these patients.

CAFs secreted exosomes promote metastasis and chemotherapy resistance by enhancing cell stemness and epithelial-mesenchymal transition in colorectal cancer

BACKGROUND

Cancer associated fibroblasts (CAFs) are key stroma cells that play dominant roles in tumor progression. However, the CAFs-derived molecular determinants that regulate colorectal cancer (CRC) metastasis and chemoresistance have not been fully characterized.

METHODS

CAFs and NFs were obtained from fresh CRC and adjacent normal tissues. Exosomes were isolated from conditioned medium and serum of CRC patients using ultracentrifugation method and ExoQuick Exosome Precipitation Solution kit, and characterized by transmission electronic microscopy, nanosight and western blot. MicroRNA microarray was employed to identify differentially expressed miRNAs in exosomes secreted by CAFs or NFs. The internalization of exosomes, transfer of miR-92a-3p was observed by immunofluorescence. Boyden chamber migration and invasion, cell counting kit-8, flow cytometry, plate colony formation, sphere formation assays, tail vein injection and primary colon cancer liver metastasis assays were employed to explore the effect of NFs, CAFs and exosomes secreted by them on epithelial-mesenchymal transition, stemness, metastasis and chemotherapy resistance of CRC. Luciferase report assay, real-time qPCR, western blot, immunofluorescence, and immunohistochemistry staining were employed to explore the regulation of CRC metastasis and chemotherapy resistance by miR-92a-3p, FBXW7 and MOAP1.

RESULTS

CAFs promote the stemness, epithelial-mesenchymal transition (EMT), metastasis and chemotherapy resistance of CRC cells. Importantly, CAFs exert their roles by directly transferring exosomes to CRC cells, leading to a significant increase of miR-92a-3p level in CRC cells. Mechanically, increased expression of miR-92a-3p activates Wnt/β-catenin pathway and inhibits mitochondrial apoptosis by directly inhibiting FBXW7 and MOAP1, contributing to cell stemness, EMT, metastasis and 5-FU/L-OHP resistance in CRC. Clinically, miR-92a-3p expression is significantly increased in CRC tissues and negatively correlated with the levels of FBXW7 and MOAP1 in CRC specimens, and high expression of exosomal miR-92a-3p in serum was highly linked with metastasis and chemotherapy resistance in CRC patients.

CONCLUSIONS

CAFs secreted exosomes promote metastasis and chemotherapy resistance of CRC. Inhibiting exosomal miR-92a-3p provides an alternative modality for the prediction and treatment of metastasis and chemotherapy resistance in CRC.

[Research progress of maternal immunization]

Maternal immunization is an immune strategy that protects both mothers and early-life infants from disease by the vaccination of pregnant women. The effect of maternal immunization is influenced by the types of vaccines, the timing of vaccination, the subtypes of antibodies induced by vaccines, and the health status of mothers themselves. Inactivated influenza vaccination during pregnancy and DPT vaccination during the third trimester of pregnancy have been widely used in the world, while Hepatitis B vaccine, pneumococcal and meningococcal vaccines also show good efficacy and safety in pregnant women. This article reviews the research progress of Maternal Immunization in order to provide a reference for Maternal Immunization planning and policymaking in China.

FMNL2 destabilises COMMD10 to activate NF-κB pathway in invasion and metastasis of colorectal cancer

BACKGROUND

Diaphanous-related formins (DRFs), actin necleator, have been known to participate in the progression of cancer cells. We previously reported that FMNL2 (Formin-like2), a member of DRFs, was a positive regulator in colorectal cancer (CRC) metastasis, yet proteins and pathways required for the function of this pro-invasive DRFs remain to be identified.

METHODS

The relationship between FMNL2 and COMMD10 was examined using Co-IP, GST pull-down, immunofluorescence and in vitro ubiquitination assay. The in vitro and in vivo function of COMMD10 in CRC was evaluated using CCK-8 proliferation assay, plate colony formation, cell cycle, apoptosis and animal models. The inhibition of NF-κB signalling by COMMD10 was detected using dual-luciferase reporter assay and western blotting. Co-IP, GST pull-down and nuclear protein extraction assay were performed to evaluate the effect on p65 by COMMD10. Real-time PCR and western blotting were performed to detect expressions of FMNL2, COMMD10 and p65 in paired tissues.

RESULTS

FMNL2 targets COMMD10 for ubiquitin-mediated proteasome degradation in CRC cells. COMMD10 targets p65 NF-κB (nuclear factor-κB) subunit and reduces its nuclear translocation, thereby leading to the inactivation of NF-κB pathway and suppression of CRC invasion and metastasis. Inhibition of NF-κB signalling by COMMD10 is necessary for FMNL2-mediated CRC cell behaviours. Downregulation of COMMD10 predicts poor prognosis of CRC patients. The expressions of FMNL2, COMMD10 and p65 are highly linked in CRC tissues.

CONCLUSIONS

These data demonstrate that the FMNL2/COMMD10/p65 axis acts as a critical regulator in the maintenance of metastatic phenotypes and is strongly associated with negative clinical outcomes.

Down-regulation of DAB2IP promotes colorectal cancer invasion and metastasis by translocating hnRNPK into nucleus to enhance the transcription of MMP2

DOC-2/DAB2 interacting protein (DAB2IP) is a RasGAP protein that shows a suppressive effect on cancer progression. Our previous study showed the involvement of transcription regulation of DAB2IP in metastasis of colorectal cancer (CRC). However, the molecular mechanisms of DAB2IP in regulating the progression of CRC need to be further explored. Here, we identified heterogeneous nuclear ribonucleoprotein K (hnRNPK) and matrix metalloproteinase 2 (MMP2) as vital downstream targets of DAB2IP in CRC cells by two-dimensional fluorescence difference gel electrophoresis and cDNA microassay, respectively. Mechanistically, down-regulation of DAB2IP increased the level of hnRNPK through MAPK/ERK signaling pathway. Subsequently, translocation of hnRNPK into nucleus enhanced the transcription activity of MMP2, and therefore promoted invasion and metastasis of CRC. Down-regulation of DAB2IP correlated negatively with hnRNPK and MMP2 expressions in CRC tissues. In conclusion, our study elucidates a novel mechanism of the DAB2IP/hnRNPK/MMP2 axis in the regulation of CRC invasion and metastasis, which may be a potential therapeutic target.

Role and timing of second-line therapies for patients with recurrent platinum-resistant ovarian epithelial cancer

OBJECTIVE

To explore the regimens and prognoses of second-line therapies for recurrent platinum-resistant ovarian epithelial cancer (OEC).

MATERIALS AND METHODS

The clinical profiles and second-line regimens were retrospectively analyzed for 65 recurrent platinum-resistant OEC patients treated at Zhejiang Provincial Tumor Hospital during January 2003 to January 2013. In conjunction with literature reviews, the second-line therapies for platinum-resistant recurrent OEC were discussed.

RESULTS

Their average age was 55.2 years. The stages were I (n=4), II (n=3), III (n=45), and IV (n=13). The predominant type was serous adenocarcinoma (n=47, 72.3%). Chemotherapy was refused (n=14) and resistant (n=5 1). One case was lost to follow-up and another three withdrew early. An average of four chemotherapeutic courses were offered in 61 cases. Among them, five cases selected chemotherapy after a second operation. The average therapy-free interval (TFI) was 3.5 months. The efficacies were evaluated for 61 cases. CR (n=5) and partial remission (PR, n=22). The overall survival (OS) rate was 43.6% and average progression-free survival (PFS) was 15.44 months.

CONCLUSION

The efficacy of second-line therapy for recurrent platinum-resistant OEC is rather poor and the feasibility and efficacy of second operation are to be further explored.

FBX8 is a metastasis suppressor downstream of miR-223 and targeting mTOR for degradation in colorectal carcinoma

F-box proteins are critical components of the SKP1-CUL1-F-box (SCF) E3 ubiquitin ligases and involved in the ubiquitin-dependent proteolytic pathway. Dysregulation of F-box protein-mediated proteolysis often leads to human malignancies. F-box only protein 8 (FBX8), a novel component of F-box proteins, is down-regulated in several tumors and closely correlates with tumor progression. However, little is known about its function, regulatory mechanisms and substrates in the progression of colorectal carcinoma (CRC). Combining microRNA (miRNA) assay, functional characterization, mechanistic studies with clinical validation, we identify FBX8 as a CRC metastasis suppressor downstream of miR-223, a metastasis promoting miRNA that is transcriptionally regulated by Myocyte enhancer factor (MEF2A). mTOR is a substrate of FBX8 for ubiquitin-mediated degradation and is required for FBX8 induced cell proliferation and invasion in CRC cells. FBX8 is down-regulated in human CRC tissues and correlates with MEF2A, miR-223 and mTOR expression levels. Notably, low FBX8 expression status in CRC tissues was a significant prognostic factor for poor overall survival of patients. These findings illustrate FBX8 as a metastasis suppressor that functions through mTOR signaling pathway and has significant prognostic power.

The FOXD3/miR-214/MED19 axis suppresses tumour growth and metastasis in human colorectal cancer

Background:

MiR-214 is aberrantly regulated in several tumours, but its underlying mechanisms in colorectal cancer (CRC) metastasis remain largely unknown. This study aimed to demonstrate the function and potential mechanism of miR-214 in regulating invasion and metastasis of CRC.

Methods:

The transcription factor and targets of miR-214 were predicted by bioinformatics and validated using ChIP and dual-luciferase reporter assay. DNA methylation status was explored using bisulphite sequencing PCR. The in vitro and in vivo function of miR-214 in CRC was evaluated using MTT, plate colony formation, Matrigel invasion and animal models. Real-time PCR or western blotting was performed to detect FOXD3, miR-214 and MED19 expressions in CRC cells and clinical specimens.

Results:

MiR-214 was downregulated in CRC and was significantly correlated with lymphatic metastasis. Downregulation of miR-214 might due to promoter hypermethylation in CRC. FOXD3 was validated as a transcription factor of miR-214 by ChIP assay. Dual-luciferase assay identified MED19 as a target of miR-214 in CRC. In vitro and in vivo experiments showed that miR-214 mediated the inhibiting effect of FOXD3 on proliferation, invasion and metastasis by targeting MED19. Spearman's correlation analysis showed a positive correlation between FOXD3 and miR-214, and negative correlations between FOXD3 and MED19, miR-214 and MED19 in CRC cells and clinical specimens.

Conclusions:

FOXD3/miR-214/MED19 axis is important for the regulation of growth, invasion and metastasis of CRC. Targeting the miR-214-mediated axis might be helpful for the treatment of CRC.

Enantioselective Construction of Cyclobutanes: A New and Concise Approach to the Total Synthesis of (+)-Piperarborenine B

A highly diastereoselective and enantioselective Cu(II)/SaBOX-catalyzed [2 + 2] cycloaddition of methylidenemalonate and multisubstituted alkenes was developed to furnish optically active cyclobutanes in high yields with >99/1 dr and up to >99% ee. By application of the newly developed method, the total synthesis of (+)-piperarborenine B was completed in eight steps from methylidenemalonate and olefin in 17% overall yield with >99/1 dr and 99% ee.

Highly diastereoselective and enantioselective formal [4 + 3] cycloaddition of donor-acceptor cyclobutanes with nitrones

The first highly diastereoselective and enantioselective catalytic formal [4 + 3] cycloaddition of 1,1-cyclobutane diester with nitrone has been developed. Sterically hindered chiral SaBOX/Cu(II) complex promotes the reaction efficiently with a broad substrate scope, producing a range of multifunctionalized optically active 1,2-oxazepanes with excellent stereocontrol (up to >99/1 dr and 97% ee).

Primary structure similarity analysis of proteins sequences by a new graphical representation

A new graphical description of the primary structure of protein sequences is introduced. First, a three-dimensional space discrete point set of a protein sequence is created based on the three main physicochemical properties of the amino acids. Secondly, a continuous cubic B-spline curve interpolating the amino acid points is constructed to represent the shape of the protein sequence. Then the geometric properties (curvature and torsion) of the continuous curve are extracted for the purpose of analyzing the similarity between protein sequences. Finally, an improved Canberra distance comparison is introduced for the similarity analysis of protein sequences with different lengths. Experimental results show that our method is effective for the similarity comparison of protein sequences.

An improved reverse dot hybridization for simple and rapid detection of adefovir dipivoxil-resistant hepatitis B virus

Early detection of adefovir dipivoxil-resistant mutants during long-term treatment of chronic hepatitis B virus (HBV) infection with this drug is of great clinical importance. We developed an improved reverse dot hybridization test for simple and rapid detection of the rtA181V/T and rtN236T mutations associated with adefovir dipivoxil resistance in chronic hepatitis B patients. Probes were designed for genotypes B, C, and D of this resistance characteristic; a total of 70 clinical samples were analyzed with this improved reverse dot hybridization assay. Its usefulness was validated by comparing with sequencing data. Discordant results were confirmed by subclone sequencing. This reverse dot hybridization assay was sufficiently sensitive to detect 10(3) copies/mL; it also detected adefovir dipivoxil-resistant mutant strains when they comprised more than 5% of a mixed virus population. This reverse dot hybridization array correctly identified adefovir dipivoxil-resistant mutants; it had high concordance (98.5%) with direct sequencing data. There was no clear relationship between the HBV genotype and the development of adefovir dipivoxil-resistant mutants. This reverse dot hybridization assay proved to be simple and rapid for detection of rtA181V/T and rtN236T mutations associated with resistance to adefovir dipivoxil.

A specialized plug-in software module for computer-aided quantitative measurement of medical images

This paper presents a specialized system for quantitative measurement of medical images. Using Visual C++, we developed a computer-aided software based on Image-Pro Plus (IPP), a software development platform. When transferred to the hard disk of a computer by an MVPCI-V3A frame grabber, medical images can be automatically processed by our own IPP plug-in for immunohistochemical analysis, cytomorphological measurement and blood vessel segmentation. In 34 clinical studies, the system has shown its high stability, reliability and ease of utility.

The value of MG7 antigen in predicting cancerous change in dysplastic gastric mucosa

The aim of this study was to ascertain whether MG7Ag is a useful predictor of evolution of gastric dysplasia to carcinoma. A total of 1090 patients with confirmed dysplasia were stained immunohistochemically with MG7 monoclonal antibody by the ABC method. A prospective follow-up study was undertaken on 19 patients with MG7Ag positive staining and 16 with MG7 negative staining over a period of 10-78 months. The expression of MG7Ag was also compared in another two groups by conducting retrospective studies. One group showed an evolution into gastric cancer over 2-4 years, the other did not. Quantitative analysis of MG7Ag expression was carried out on the last two groups. The receiver operating characteristic curve and Youden index were used to assess the best critical value for MG7Ag. MG7Ag was found positive in 456/1090 cases (41.8%) with dysplasia. Prospective follow-up of 35 patients showed that 6/19 patients with MG7Ag positive staining developed gastric cancer, but there were no carcinomatous changes in 16 patients with MG7 negative staining. The results of MG7Ag expression in 72 cases with retrospective follow-up showed there were 24 with positive immunostaining among 34 cancerous cases (70.6%), and only 7 in 38 non-cancerous cases (18.4%) (p<0.01). Image analysis showed that an average MG7Ag density index ++0.19 could be regarded as the critical value for high risk of gastric mucosa with dysplasia evolving to cancer. Positive MG7Ag expression in gastric mucosa of patients with dysplasia, especially in cases with a density index ++0.19, was an indicator of high risk of malignant change.

Microvascular permeability of rat cerebral pia mater by using image computer analysis

Microcirculation viviperception and fluorescent tracer techniques were used and digital image analysis applied for quantitative measurement of fluorescein sodium (FiNa) permeability in microvessels of the cerebral pia mater. The diffusion permeation equations of FiNa within the blood vessels and through the vessel walls into the perivascular tissue of normal rats and ischemic rats were established with two vessels as study object, thus the permeation speed equations under different ischemic conditions were deduced. Based on analysis of the results, we deduced the relation between the permeability and the intersection angle of two vessels.

RESULT

logarithm model showed a good fit of the experiment data. The permeation equation showed logarithmic distribution and then tended towards stability. FiNa could pass through microvessel walls with the highest speed in the one-hour ischemic rat group, and the permeation speed of FiNa in rats receiving reperfusion after twelve hours of ischemia was much faster than that in normal rats.

CONCLUSION

the method can be useful for quantitative analysis of cerebral pia mater microvascular permeability

Polymorphism of flagellin A gene in Helicobacter pylori

AIM: To study the polymorphism of flagellin A genotype and its significance in Helicobacter pylori (H. pylori).

METHODS: As the template, genome DNA was purified from six clinical isolates of H. pylori from outpatients, and the corresponding flagellin A fragments were amplified by polymerase chain reaction. All these products were sequenced. These sequences were compared with each other, and analyzed by software of FASTA program.

RESULTS: Specific PCR products were amplified from all of these H. pylori isolates and no length divergence was found among them. Compared with each other, the highest ungapped identity is 99.10%, while the lowest is 94.65%. Using FASTA program, the alignments between query and library sequences derived from different H. pylori strains were higher than 90%.

CONCLUSION: The nucleotide sequence of flagellin A in H. pylori is highly conservative with incident divergence. This information may be useful for gene diagnosis and further study on flagellar antigen phenotype.

Relationship between genotype and phenotype of flagellin C in Salmonella

AIM: To discover the relationship between the genotype and antigen serotype of flagellin C among Salmonella strains.

METHODS: Fragment of Salmonella flagellin C in plasmid pLS408 was cloned, sequenced and compared with the corresponding sequence in other strains. Salmonella strains including two typhi strains, one paratyphoid strain, one enteritidis and one typhimurium strain were isolated from outpatients. Genome DNA was purified respectively from these clinical isolates, then the corresponding flagellin C fragment was amplified by polymerase chain reaction, and the amplification products were analyzed by agarose gel electrophoresis.

RESULTS: The cloned fragment includes 582 nucleotides encoding the variable region and partial conservative region of Salmonella flagellin C in plasmid pLS408. With comparison to the corresponding sequences reported previously, there is only a little difference from other strains with the same flagellar serotype in both nucleotide and amino acid level. Specific PCR products were amplified in Salmonella strains with flagellar serotype H-1-d including S. muenchen, typhi and typhimurium, but not in S. paratyphoid C or S. enteritidis strains.

CONCLUSION: In this experiment, the specificity of nucleotide sequence could be found in flagellin C central variable regions as it exists in flagellar serotypes in Salmonella. It may be helpful to developing a rapid, sensitive, accurate and PCR-based method to detect Salmonella strains with serotype H-1-d.

[ICAM-1 expression of rat brain microvascular endothelial cells caused by fluid shear force]

We studied the effect of shear stress (SS) on intercellular adhesion molecule-1 (ICAM-1) expression of rat brain microvascular endothelial cells (RBMECs) using the parallel plate flow chamber method. It was demonstrated that RBMECs showed a time-dependent, but not a force-dependent, upregulation in ICAM-1 expression. Endothelial cell surface expression of ICAM-1 in the supernatants of RBMECs exposed to SS was not changed, thus excluding the possibility that the upregulated expression is due to the factors synthesized by these cells. These data throw light on understanding the signal transduction pathway inside the endothelial cells under the effect of SS.

Pertussis toxin treatment prevents 5-HT(5a) receptor-mediated inhibition of cyclic AMP accumulation in rat C6 glioma cells

We have investigated the functional coupling of the rat 5HT(5a) receptor subtype to adenylate cyclase in a rat C6 glioma cell line. In 5HT(5a) receptor-transfected cells, 5HT caused a concentration-dependent inhibition of forskolin-stimulated cAMP accumulation, with an EC(50) value of 41 nM and a maximal effect of 57% inhibition. This effect was dependent on the concentration of forskolin used to elevate cAMP levels. Methiothepin (1 mcM), which has high affinity for the 5HT(5a) receptor, antagonized the 5HT(5a) receptor-mediated inhibition, and unmasked a stimulation of cAMP formation similar to that observed in untransfected cells, whereas ketanserin (0.1 mcM) enhanced the inhibitory effect of 5HT. Pertussis toxin treatment (0.5 mcg/ml) completely blocked the inhibitory effect of 5HT on cAMP formation, also revealing increase in cAMP accumulation. Pretreatment of the transfected membranes with pertussis toxin abolished subsequent ADP-ribosylation of a 41 kDa protein, correlating the cAMP effect with a functional uncoupling of an inhibitory G protein from its receptor. These results demonstrate an efficient functional coupling of the rat 5HT(5a) receptor to the inhibition of adenylate cyclase via a pertussis toxin-sensitive G[alpha(i)], inhibitory G-protein.

Antitumor components from an actinomycete strain 6011W

Three bioactive compounds that inhibited nucleoside transport were isolated from the cultured broth of Streptoverticillium sp. 6011W. The structures of those compounds were characterized as cinnamamide, N-(tetrahydro-2-oxo-3-thienyl)-acetamide and benzamide, respectively. They all inhibited radiolabeled thymidine transport into Ehrlich carcinoma cells, with IC50 values of 30.4, 97.2 and 85.4 microM, respectively. When administered i.p., cinnamamide not only inhibited the growth of transplanted tumors but also reduced the number of lung metastases in mice bearing Lewis lung carcinoma. The results suggest that nucleoside transport inhibition assay is a valuable model to search for antitumor agents of natural origin.

[Ceramide pathway]

Ceramide may be generated from many metabolism routes. As a novel second messenger, ceramide plays important roles in a variety of physiologic or pathologic events relating to cellular growth, proliferation, differentiation, apoptosis and injuries. It is expected that new insights into the ceramide pathway would promote our understanding of the complex mechanisms for signal transduction.

Enhancement of glucocorticoid receptor-mediated gene expression by cellular stress: evidence for the involvement of a heat shock-initiated factor or process during recovery from stress

Recent reports have demonstrated the ability of cellular stress to cause a large increase in the maximal levels of steroid receptor-mediated gene expression, a process we refer to as the heat shock potentiation effect (HSPE). In the present work, we have analyzed the time of appearance of the HSPE on the glucocorticoid receptor (GR) of L929 cells stably-transfected with the MMTV-CAT reporter plasmid (LMCAT2 cells). In LMCAT2 cells exposed to heat shock (43 degrees C, 2-h) before addition of 1 microM dexamethasone, the first appearance of HSPE (CAT levels greater than hormone-alone) occurred at 8 h of recovery and continued to increase by 24 h of recovery. Treatment of LMCAT2 cells with 1 microM dexamethasone for 2 h before heat or chemical shock (sodium arsenite) resulted in the same delayed onset pattern for the HSPE. Based on a [35S]methionine assay and tests of L929 cells stably transfected with the constitutive pSV2-CAT reporter, evidence is provided that the delayed appearance of the HSPE is not due to the heat shock block of general protein synthesis or to specific repression of CAT mRNA expression or translation. By using short-term incubations (4 h) with dexamethasone during the recovery period, the peaks of HSPE expression during recovery were determined to be 12-16 h for CAT enzyme activities, and 4-8 h for CAT mRNA expression. Taken together, these results provide evidence that the timing of the HSPE is not dependent on the rate of GR activation, or on the type of stress, but rather on a factor or process that is either synthesized or activated during the recovery period following stress.

Antibiotic C3368-A, a fungus-derived nucleoside transport inhibitor, potentiates the activity of antitumor drugs

Antibiotic C3368-A (CA) is produced by a fungus strain from a soil sample collected in Antarctica. CA markedly inhibited radiolabeled thymidine and uridine transport in mouse Ehrlich carcinoma cells, its 50% inhibitory concentration (IC50) being 4.6 and 7.7 microM, respectively. In clonogenic assay, CA displayed a synergistic effect with methotrexate (MTX), mitomycin C (MMC), 5-fluorouracil (5FU), and Adriamycin (ADR) against human oral epidermoid carcinoma KB cells. CA also markedly enhanced the inhibitory effect of 5FU and ADR on the proliferation of human hepatoma BEL-7402 cells as determined by the p-nitrophenyl-N-acetyl-beta-D-glucosaminide (NAG) enzyme-reaction assay. 5FU or ADR cytotoxicity was not augmented by CA in human fetal lung 2BS cells. In vivo, CA significantly potentiated the inhibitory effect of MMC against colon carcinoma 26 in mice. No significant augmentation of toxicity by the combination was found in treated mice. The results suggest that CA, the newly found nucleoside-transport inhibitor, may be useful in potentiation of the effect of antitumor drugs.

[The expression of mutant p53 gene in gastric carcinoma]

Loss or inactivation of p53 gene--a suppressor oncogene has been considered to be one of the important mechanisms in the development of human tumors. One of the evidences for mutation of allelic gene of p53 is the identification of p53 protein concentrated in the nuclei of related cells. By using ABC immunohistochemical method, we studied the expression of p53 in cryostatic sections of the tumor tissue and adjacent mucosa resected from 38 patients with gastric cancer. p53 was found to be positive in the nuclei with intensive staining in 24 out of 38 cases with carcinoma (63.2%). p53 positive cells were distributed diffusively in the cancer tissue. All the adjacent mucosa specimens except 10 were negatively stained with p53 monoclonal antibody. These 10 specimens including 3 with dysplasia and 4 with metaplasia were only weakly stained. p53 was also found to be positive in 18 out of 23 cancer patients with metastasis in perigastric lymph nodes (78.3%). We also studied in the same section the nucleolar organizer region-associated proteins (AgNORs) with using silver staining technique to find if there is any relationship between p53 gene mutation and the activity of rRNA transcription of tumor cells. The number of AgNORs dots per nucleus detected in gastric cancer sections with positive staining of p53 (9.9 + 2.14) was greater than those with p53 negative staining (7.2 + 1.68). There was a significant statistical difference between the two groups (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Potentiation of glucocorticoid receptor-mediated gene expression by heat and chemical shock

We have examined the effects of heat shock on glucocorticoid receptor (GR)-mediated gene transcription in an L929 cell line derivative (LMCAT2) stably transfected with the mouse mammary tumor virus-chloramphenicol acetyltransferase (MMTV-CAT) reporter plasmid. Exposure of the LMCAT2 cells to heat or chemical shock resulted in a large increase in dexamethasone (Dex)-induced expression of CAT enzyme activity. This potentiation of hormone-induced MMTV-CAT expression was dependent on the magnitude of the stress event and on the Dex concentration, with maximal increases observed for 1 microM Dex after 2 h at 43 C or 2 h at 200 microM sodium arsenite. Heat shock potentiation of MMTV-CAT expression was not seen in an L929 cell derivative devoid of GR or in LMCAT2 cells treated with RU486 antagonist, suggesting that this effect of stress on CAT gene expression was mediated by the GR. Using a quantitative Western blot procedure, the amount of GR protein in the nucleus of cells subjected to combined heat shock and Dex treatment was no greater than the amount of nuclear GR in cells treated with hormone alone, indicating that the stress potentiation effect was not the result of increased nuclear translocation or retention by the GR. In addition, equally strong potentiations of MMTV-CAT expression were observed for cells subjected to heat shock either before or after Dex-mediated translocation of the GR to the nucleus. Thus, the major effect of stress on GR transcription enhancement activity appears to occur after the GR is bound to its high affinity nuclear acceptor sites. We have used a series of MMTV-CAT reporter constructs containing varying portions of the long terminal repeat regulatory region to show that a putative heat shock transcription factor-binding sequence at position -437 of the long terminal repeat is not required for this effect of heat shock on MMTV-CAT expression. A stress-induced increase in hormone-mediated CAT gene expression was observed for a minimal CAT reporter controlled by two synthetic glucocorticoid response elements and a TATA box sequence. Thus, it is unlikely that any DNA-binding transcription factor, other than GR, is required for this effect of stress on transcription by the hormone-bound GR. Based on these results, a model of heat shock enhancement of GR-mediated gene expression is developed in which stress acts on the DNA-bound GR, on a putative heat shock-activated adaptor, or on components of the RNA-polymerase-II complex.

Detection of antigen-specific immune complexes in sera of gastric and esophageal cancer patients

Using the murine monoclonal antibodies against human gastric cancer cell antigens designated MG7 and MGd1, we developed a sandwich ELISA to detect the levels of antigen-specific immune complexes (IC) in human sera. By this assay, only 6.7%(6/90) of healthy blood donors and 9.2%(6/65) of patients with chronic gastritis had antigen-specific IC in sera exceeding the cut-off value. Whereas 21.4%(6/28) of patients with colorectal cancer, 18.2%(4/22) of patients with hepatocellular cancer, 11.4%(4/35) of patients with lung cancer and 9.5%(2/21) of patients with breast cancer had elevated levels of the antigen-specific IC. In contrast, 58.7%(54/92) of patients with gastric cancer and 53.3%(24/45) of patients with esophageal cancer were positive for this antigen-specific IC. Determination of levels of antigen-specific IC in sera may be useful in serologic diagnosis of patients with gastric and esophageal cancer.

[Labeling of granulocytic granules with RNase-gold probes]

By using ribonuclease-gold (RNase-G) probes, ultrastructural localization of ribonucleic acid (RNA) was performed in inflammatory cells from gastric mucosa biopsies of gastric cancer and gastritis, and in peripheral leukocytes from normal subjects as well as from granulocytic leukemia patients. Electron microscopically, the azurophilic granules of monocytes and lymphocytes in gastric mucosa were not labeled by RNase-G, while various cytoplasmic granules of neutrophils, eosinophils and basophils were all positively labeled. Labeling of the peripheral leukocytes from normal subjects was the same as above. It is important to find in the present study that the cytoplasmic granules of the peripheral leukemic cells from granulocytic leukemia patients were not labeled by RNase-G. The significance of the afore-mentioned findings lies on one hand in the fact that it could make a revision of the conventional views of the granular composition. On the other hand, the data indicate that the RNase-G technique is potentially explorable for future clinical utilization.

Diagnostic significance of gastric cancer associated antigens (MG-AGS) in serum, ascitic fluid and gastric juice

A group of monoclonal antibodies against gastric cancer, pooled in equal proportions, was used to investigate their corresponding antigens (MG-Ags) in serum and body fluid of patients with gastrointestinal cancer and benign diseases using microsphere-ELISA method. The mean serum level (plus 3 standard deviations) in 59 normal subjects was arbitrarily set as the positive threshold value. The positive rate was found to be 68.8% (135/196) in sera of patients with gastric cancer, 70% (14/20) in colonic cancer, 72.2% (24/33) in rectal cancer, 43.8% (7/16) in esophageal cancer, 45.5% (5/11) in cholecystic cancer and 34.9% (15/43) in lung cancer, which, however, was not found in primary liver cancer, pancreatic cancer and ovarian cancer. In 214 patients with benign diseases, a false positive rate was 7.48%. In gastric juice and ascitic fluid of patients with gastric cancer, the positive rates were found to be 61.7% (27/44) and 83.3% (20/24) respectively. These antigens were also determined repeatedly in sera of patients with gastric cancer who had undergone gastrectomy. It was found that the level of MG-Ags in sera began to decrease at 8-10 days after operation. These results suggest that the determination of MG-Ags is useful in the diagnosis of gastrointestinal cancer and evaluation of the treatments.

Studies on gastrin in duodenal ulcer

By immunocytochemical method and radioimmunoassay, the gastrin secreting cells (G cells) and gastrin concentration in antral mucosa, gastric juice and serum in 20 patients with duodenal ulcer (DU) were studied. The number of G cells and gastrin concentration in antral mucosa showed no significant difference as compared with normal control. The number of G cells in patients with DU and antral atrophy was much higher than those with antral atrophy but with DU. It indicated that G cells were increased in number in DU, and the gastrin concentration in gastric juice (271.11 +/- 255.25 pg/ml) was much higher than in sera (74.71 +/- 43.07 pg/ml). G cells were distributed in different parts of pyloric glands, showing that gastrin in gastric juice should come directly from G cells. The disturbance of feedback mechanism in regulating gastric acidity might be an important role in hypersecretion of gastric acid in DU. The increase of gastrin concentration in gastric juice might be closely related to hyperplasia of parietal cells.

A new macromolecular antitumor antibiotic, C-1027. I. Discovery, taxonomy of producing organism, fermentation and biological activity

Strain C-1027, an actinomycete isolated from a soil sample collected in China, was found to produce the new antibiotic, C-1027. From taxonomical studies on its morphological, cultural and physiological characteristics, this antibiotic-producing strain was identified as Streptomyces globisporus C-1027. Antibiotic C-1027 has antimicrobial activity against most Gram-positive bacteria but not against Mycobacterium sp. or Gram-negative bacteria. This antibiotic shows remarkable activity in spermatogonial assay and potent cytotoxicity against KB carcinoma cells in vitro, and exhibits inhibition on transplantable tumors in mice.