[Ion chromatography-pulsed amperometry method for determination of trace hydrogen sulfide in air].

Hydrogen sulfide (H2S) is a pervasive gaseous pollutant that emits the characteristic odor of rotten gas, even at low concentrations. It is generated during various industrial processes, including petroleum and natural gas refining, mining operations, wastewater treatment activities, and refuse disposal practices. According to statistics from the World Health Organization (WHO), over 70 occupations are exposed to H2S, rendering it a key monitoring factor in occupational disease detection. Although H2S has legitimate uses in the chemical, medical, and other fields, prolonged exposure to this gas can cause severe damage to the respiratory and central nervous systems, as well as other organs in the human body. Moreover, the substantial release of H2S into the environment can lead to significant pollution. This noxious substance has the potential to impair soil, water, and air quality, while disrupting the equilibrium of the surrounding ecosystems. Therefore, sulfide has become one of the most commonly measured substances for environmental monitoring worldwide. Achieving the stable enrichment and accurate detection of low-level H2S is of great significance. Common methods for detecting this gas include spectrophotometry, chemical analysis, gas chromatography, rapid field detection, and ion chromatography. Although these methods provide relatively reliable results, they suffer from limitations such as high detection cost, low recovery, lack of environmental friendliness, and imprecise quantification of low-concentration H2S. Furthermore, the sampling processes involved in these methods are complex and require specialized equipment and electrical devices. Additionally, approximately 20% of the sulfides in a sample are lost after 2 h in a conventional alkaline sodium hydroxide solution, causing difficulties in preservation and detection. In this study, an accurate, efficient, and cost-saving method based on ion chromatography-pulse amperometry was developed for H2S determination. A conventional IonPac AS7 (250 mm×4 mm) anion-exchange column was employed, and a new eluent based on sodium hydroxide and sodium oxalate was used to replace the original sodium hydroxide-sodium acetate eluent. The main factors influencing the separation and detection performance of the proposed method, including the pulse amperage detection potential parameters and integration time, as well as the type and content of additives in the stabilizing solution, were optimized. The results showed that the proposed method had a good linear relationship between 10 and 3000 µg/L, with correlation coefficients (r2) of up to 0.999. The limits of detection (S/N=3) and quantification (S/N=10) were 1.53 and 5.10 µg/L, respectively. The relative standard deviations (RSDs) of the peak area and retention time of sulfides were less than 0.2% (n=6). The new method exhibited excellent stability, with up to 90% reduction in reagent costs. Compared with conventional ion chromatography-pulse amperometry, this method is more suitable for detecting low concentrations of sulfides in actual samples. Sulfides in a 250 mmol/L sodium hydroxide-0.8% (mass fraction) ethylenediaminetetraacetic acid disodium salt solution were effectively maintained for over 10 h. The new stabilizer significantly improved the reliability of both large-scale and long-term detection. The recovery of the proposed method was investigated by combining the system with a badge-type passive sampler. This sampling method requires no power devices; it is inexpensive, simple to operate, and can realize long-term sampling without the need for skilled personnel. Moreover, it can overcome the influence of short-term changes in pollutant concentration. The sampling results have high reference value for large-scale intervention-less pollutant monitoring in ultraclean rooms, museum counters, and other places. The results demonstrated that the recovery of the proposed method was greater than 95% for the blank sample and 80% for the sample plus standard solution. Finally, the newly established method was applied to determine H2S levels in air samples collected via passive sampling at school garbage stations. The measured results did not exceed the national limit.

[Determination of electrosynthesized urea products by igh performance liquid chromatography based n porous graphitic carbon column].

Urea is a simple organic compound that is widely used in both the industry and daily life. Compared with conventional methods, the preparation of urea by electrochemical synthesis is more environmentally friendly and sustainable. However, after the reaction, low amounts of urea and high concentrations of inorganic ions, including [Formula: see text] concentration was achieved without interference. Thus, the developed method can be applied for the detection of trace urea and other related ions in urea-containing electrolyte products.

Comparison of modeling effects of two different 7, 12-dimethylbenza anthracene induced breast cancer models in tree shrew / 中华肿瘤杂志

Objective@#To explore the feasibility of 7, 12-dimethylbenz[a] anthracene (DMBA) induced tree shrew breast cancer model, and compare the effects of two administration modes by gavage and mammary gland injection.@*Methods@#A total of 40 tree shrews were randomly divided into two groups (20 animals per group): DMBA gavage group and mammary gland injection group. DMBA was dissolved in edible vegetable oil. For gavage group, tree shrews were administered with DMBA solutions (15 mg/kg) by gavage once a day. For mammary gland injection group, DMBA solution (10 mg/kg) was injected into the mammary fat pad of tree shrews, and the injection was performed for a total of 3 times. From the first administration of DMBA, medroxyprogesterone acetate (MPA, 100 mg/kg) was intramuscularly injected into the muscles of the lateral thighs of tree shrews at the same time, for a total of 5 times. The tumorigenesis and survival of tree shrews were monitored. The tumor histological morphology was observed by HE staining. The expression of estrogen receptor (ER), progesterone receptor (PR), cytokeratin5/6 (CK5/6) and human epidermal factor receptor-2 (HER-2) was detected by immunohistochemical staining.@*Results@#In the gavage group, there were 10 deaths, and 4 tree shrews developed mammary tumors with 20.0% (4/20) tumor formation rate. The success rate of mammary cancer modeling was 10.0% (2/20), and the tumor formation time was 197.3±15.1 days. In the mammary gland injection group, there were 8 tree shrews died, and 9 tree shrews formed tumors with 45.0% (9/20) tumor formation rate. The success rate of mammary cancer modeling was 40.0% (8/20), and the tumor formation time was 71.8±19.0 days. There was no significant difference in mortality and tumor formation rate (P>0.05) between the two groups (all P>0.05). However, in the mammary gland injection group, the success rate of mammary cancer modeling was significantly higher than that in the gavage group (P<0.05), whereas the tumor formation time was markedly shorter than that in the gavage group (P<0.01). The pathological types in the gavage group included ductal hyperplasia, intraductal papilloma and ductal carcinoma in situ, while those in the breast injection group included intraductal papilloma and ductal carcinoma in situ. In both groups, immunohistochemical staining showed the negative expression of HER-2 but positive expression of ER, PR and CK5/6 with varying degrees.@*Conclusion@#Both the DMBA gavage and mammary gland injection can successfully establish the tree shrew breast cancer model, and the modeling effect of mammary gland injection is better than gavage.

Helicobacter pylori combined with MNU gavage for preparing balb/c mouse gastric cancer model / 重庆医学

Objective To investigate Helicobacter pylori combined with N-methyl-N-nitrosourea (MNU) gavage for preparing balb/c mouse gastric cancer model.Methods Eighty balb/c mice were randomly divided into four groups after 1-week adaptive feed,normal group,model group Ⅰ,Ⅱ and Ⅲ,20 cases in each group.The model group Ⅰ,Ⅱ and Ⅲ were given Helicobacter pylori bacteria liquid (CFU=109/mL) gavage,once every other day for 5 times;then,the freshly configured MNU solution 0.15,0.3,0.6 mL gavages were in turn given,MNU and pure water allocation ratio was 5mg:3mL.Once gavage per week for continuous 10 weeks.Results The model group II had 66.67% adenocarcinoma,the model group I were gastritis with mild atypical hyperplasia,and all mice in the model group III died.Conclusion This method can prepare the gastric cancer model.

Comparison of Two Molecular Assays For Detecting Smear Negative Pulmonary Tuberculosis / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To compare the performance of MTBDRplus V2 and Xpert MTB/RIF for detecting smear negative pulmonary tuberculosis (PTB).</p><p><b>METHODS</b>Clinical PTB suspects were enrolled consecutively in Anhui Chest Hospital and Xi'an Chest Hospital from January to December in 2014. The sputum samples of smear negative PTB suspects were collected and decontaminated. The sediment was used to conduct MTBDRplus V2, Xpert MTB/RIF and drug susceptibility test (DST). All the samples with discrepant drug susceptibility result between molecular methods and phenotypic method were confirmed by DNA sequencing.</p><p><b>RESULTS</b>A total of 1973 cases were enrolled in this study. The detection rates of Mycobacterium tuberculosis complex (MTBC) by MTBDRplus V2 and Xpert MTB/RIF were 27.67% and 27.98%, respectively. When setting MGIT culture result as a gold standard, the sensitivity and specificity of MTBDRplus V2 were 86.74% and 93.84%, and the sensitivity and specificity of Xpert MTB/RIF were 86.55% and 93.43%, respectively. For the detection of the resistance to rifampin, the sensitivity and specificity of MTBDRplus V2 were 94.34% and 96.62%, and the sensitivity and specificity of Xpert MTB/RIF were 88.68% and 95.96%, respectively. For the detection of the resistance to isoniazid, the sensitivity and specificity of MTBDRplus V2 were 77.38% and 98.02%, respectively.</p><p><b>CONCLUSION</b>MTBDRplus V2 and Xpert MTB/RIF can be used to detect MTBC in smear negative samples with satisfactory performance.</p>

The relationship on polymorphisms of ERCC1-4533/8092 and the susceptibility of hepatocellular carcinoma / 国际检验医学杂志

Objective To investigate the relationship on the excision repair cross complementing gene 1(ERCC1)‐4533/8092 site single nucleotide polymorphisms(SNPs) and the susceptibility to hepatocellular carcinoma(HCC) in Guangxi Zhuang population . Methods Polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) method was used to detect the ER‐CC1‐4533/8092 gene polymorphism in 88 cases with primary liver cancer and 82 cases of normal controls .Results There was no difference in the frequency distribution of ERCC1‐4533 in the case group and the control group ,the frequency distribution of the ERCC1‐8092 in the case group and the control group was different(P< 0 .05) .Compared with ERCC1‐8092 CC ,ERCC1‐C8092 CA/AA had higher risk of primary hepatocellular carcinoma(CA :OR=2 .556 ,95% CI:1 .345 -4 .855;AA :OR= 8 .667 ,95% CI:1 .000-75 .092) .ERCC1‐8092 C allele as a reference ,ERCC1‐8092 A allele can increase the risk of primary liver cancer (OR=2 .387 ,95% CI:1 .428-3 .992) .Conclusion The genetic polymorphisms of ERCC1‐8092 sites are associated with susceptibility to hepatocellular carcinoma in Guangxi Zhuang population .

A clinicopathological characteristics of 35 patients with hepatocellular carcinoma associated with bile duct tumor thrombi / 中华肝胆外科杂志

Objective To analyze the clinical and pathological characteristics of 35 hepatocellular carcinoma (HCC) patients with bile duct tumor thrombi (BDTT),and to investigate the expressions of CD133,CD90,EpCAM,CK19,VEGF,and C-kit in the tumor tissues.Methods 35 HCC patients with BDTT out of 943 HCC patients who underwent surgical treatment were studied.The expressions of biomarkers in tissue specimens were determined by immunohistochemistry.35 HCC patients without BDTT were selected using the method of stratified sampling as a control group.Results In 19 of 35 patients,the diameters of the primary tumor were less than 5 cm (range 0 ～ 17 cm,average 6.9 ± 0.7 cm).When compared to the control group,most of the primary tumors were moderately to lowly differentiated (33/35,94％ vs 18/ 35,51％),had incomplete capsules (18/35,51％ vs 3/35,8％) and micro vascular invasion (29/35,83％ vs 7/35,20％).The positive expression rates of CD90,EpCAM,CK19,VEGF,CD133,and C-kit in the group of patients with HCC with BDTT and in the control group were 82.9％,77.1％,71.4％,85.7％,80.0％,80.0％ and 57.1％,54.3％,34.3％,65.7％,54.3％,51.4％,respectively.The 1-,2-,3-year postoperative survival rates of the HCC patients with BDTT were 69％,37％,20％ respectively which were worse than the HCC patients without BDTT (1-,2-,3-year postoperative survival rates were 88％,72％,62％ respectively,P ＜ 0.05).Conclusions The prognosis of HCC patients with BDTT was worse than HCC patients without BDTT.The expressions of liver stem cell biomarkers in the tumor specimens of the group of HCC patients with BDTT were higher than the control group.These findings prompt that this kind of HCC originate from liver stem ceils.

Multicenter Evaluation of the Molecular Line Probe Assay for Multidrug Resistant Mycobacterium Tuberculosis Detection in China / 生物医学与环境科学（英文）

In order to evaluate the performance of a molecular Hain line probe assay (Hain LPA) for rapid detection of rifampicin and isoniazid resistance of Mycobacterium tuberculosis in China, 1612 smear positive patients were consecutively enrolled in this study. Smear positive sputum specimens were collected for Hain LPA and conventional drug susceptibility testing (DST). The sensitivity and specificity of Hain LPA were analyzed by using conventional DST as golden reference. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for rifampicin resistance detection were 88.33%, 97.66%, 81.54%, and 98.62%, respectively. The sensitivity, specificity, PPV and NPV for isoniazid resistance detection were 80.25%, 98.07%, 87.25%, and 96.78%, respectively. These findings suggested that Hain LPA can be an effective method worthy of broader use in China.

Changes of Kupffer cells during tree shrew chronically infected with hep-atitis B virus / 中国病理生理杂志

AIM:To explore the changes and significance of Kupffer cells in the process of tree shrew chroni -cally infected with hepatitis B virus (HBV).METHODS:The animals were divided into 3 groups.Group A consists of 6 tree shrews that were identified as persistently infected with HBV;group B consists of 3 tree shrews that were suspected as persistently infected with HBV;group C consists of 4 tree shrews that were not inoculated with HBV and were applied as normal controls.Liver biopsies were collected regularly from all animals , and the Kupffer cells were isolated , purified and primarily cultured.The techniques of flow cytometry , immunohistochemistry, lysosomal fluorescent probe staining and real-time RT-PCR were applied to determine the number and function of these Kupffer cells .RESULTS: The result showed that the count and proportion of CD 163+cells in group A were significantly higher than those in group B and group C ( P<0.05).Meanwhile, the fluorescence intensity levels of lysosomal , the number of lysozyme-positive cells and the mRNA ex-pression level of TNF-αin the Kupffer cells in group A were significantly lower than those in group B and group C ( P<0.05).CONCLUSION:Kupffer cells may play a regulatory role during host’s chronic HBV infection.

The feasibility of sputum transportation system in China: effect of sputum storage on the mycobacterial detection / 生物医学与环境科学（英文）

Sputum transportation from county-level to prefecture-level is an ideal strategy to cover the shortage of the laboratory capability in the resource-poor setting. Here, we firstly evaluated the feasibility of sputum transportation system in China by analyzing the culture and molecular diagnosis results from 1982 smear-positive patients with different delay in processing for culture. In this study, the total contamination rate was 2.32% and the total smear positive/culture negative (S+/C-) rate was 7.57%. We found that sputum specimens refrigerated for no more than 7 d before mycobacterial detection did not affect culture significantly. In addition, the invalid result rates among 0-3 d, 3-7 d, and 7+ d group were 3.63%, 3.14%, and 12.48%, respectively. Statistic analysis revealed that molecular diagnostic results while the invalid result rate of genechip for the specimen with more than 7 d delay was significantly higher (P<0.001). The refrigerators equipped in county laboratories, transport at low temperature and frequent transport services once a week will ensure the feasibility of sputum transportation system in China.

Detection and significance of the main nutritional ingredients of tree shrew’ s milk / 中国比较医学杂志

Objective To explore the basic ingredients of the tree shrew’ s( Tupaia belangeri) milk and compare with the dairy ingredients of other milks.Methods We select ten seed tree shrews after delivery ( 1 ~21 ) d with lactation mother tree shrews, and use artificial passive breastfeeding method let the young tree shrews suck breast milk,we took the milk from the young tree shrews in the stomach, directly using aseptic operation with a syringe immediately, once every two days, for consecutive three to five times, and a total of 18 mL milk was taken from each seed tree shrew.Then the milk was detected according to the national standard method for component testing.Results The total solid content of the tree shrew’ s milk was 43.63%, including 26.01%of fat, 10.41%of protein, 0.45% of lactose and 0.99%of ash content.Compared with cow's milk, the tree shrew’ s milk contained 3.36 times of total solid contents, 1.24 times of ash, 2.74 times of protein, 6.67 times of fat, and 0.09 times of lactose.Compare with baby formula milk, the tree shrew’ s milk contained 1.44 times of total solid contents, 0.20 times of ash, 0.58 times of protein, 1.53 times of fat, and 0.06 times of lactose.The trace mineral composition of the tree shrew’ s milk showed that the calcium, phosphorus, potassium, sodium, magnesium, and iron contents were 1.83 times, 2.73 times, 1.25 times, 1.93 times, 1.28 times, and 1.48 times higher than those in the cow's milk, and were 0.66 times, 0.85 times, 0.34 times, 0.26 times, 0.85 times, 0.24 times lower than those in baby formula milk.Conclusions The main nutrients of tree shrew’ s milk is of high fat, high protein and low sugar, and it can provide a basis for tree shrews artificial brood and breeding work.

Cloning, expression, and purification of a Cu/Zn superoxide dismutase from Jatropha curcas.

We report cDNA cloning, expression, purification, and characterization of a novel Cu/ Zn superoxide dismutase (SOD) from Jatropha curcas leaves. The full-length cDNA of this SOD contained a 496-bp open-reading frame (ORF) encoding 162 amino acid residues. The recombinant plasmid containing the SOD coding sequence was introduced into Escherichia coli, and the SOD was expressed as a fusion protein. The recombinant SOD was purified from a high-density fed-batch culture using a combination of immobilized metal ion affinity chromatography (IMAC) and Sephadex G25 desalting chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis indicated that the recombinant SOD was a monomeric protein with a molecular mass of approximately 16.4 kDa. Isoelectric focusing showed that this SOD was a basic protein with pI values of 7.04, 7.33, 8.62, and 8.77. The activity of the SOD was stable at 70 degrees C for 10 min, and in a broad pH range from 4 to 9. The presence of urea (up to 8 M), guanidinium chloride (up to 6 M), and 2-mercaptoethanol (up to 8 mM) had little effect on the activity. The activity decreased gradually with increasing concentrations of imidazole, hydrogen peroxide, and ethylenediaminetetraacetic acid (EDTA). Atomic absorption spectrometry showed the presence of 0.239 copper and 0.258 zinc atoms, respectively, in the SOD polypeptide.

The expression and significance of MCM7 protein in hepatocellu-lar carcinoma tissues of human, rat and tree shrew / 中国肿瘤临床

Objective:To test the expression of Minichromosome maintenance complex component 7(MCM7) protein in hepato-cellular carcinoma(HCC) of different species including human, rat and tree shrew (tupaia) by cross-species oncogenomics approach, and to investigate the relationship between the expression of MCM7 and the development of hepatocellular carcinoma and its clinical significance. Methods:Western blot and Immunohistochemistry were applied to detect the expression levels of MCM7 protein in HCC tissues,corresponding HCC-adjacent liver tissues and normal liver tissues collected from different species including human, rat and tree shrew, respectively. The clinicopathologic factors were also analyzed with the results of Immunohistochemistry. Results:Western blot analysis showed that the expression of MCM7 protein in HCC tissues of human and rat were higher than that in corresponding HCC-ad-jacent liver tissues and normal liver tissues, respectively and significantly (P0.05).There was also no significant difference between HCC-adjacent liver tis-sues and normal liver tissues in three species (P>0.05). Immunohistochemical analysis showed that MCM7 protein was mainly ex-pressed in nucleus of HCC cells, and the positive rate of MCM7 protein in HCC tissues of human, rat and tree shrew were significantly higher than that in corresponding HCC-adjacent liver tissues and normal liver tissues, respectively (P0.05). Moreover, the protein level of MCM7 was intimately related to patient's HCC stage, extrahepatic metastases and postoperative recurrence (P<0.05). Conclusion:MCM7 protein might play a pivotal role in hepatocarcinogenesis. In addition, it was probably related to patient's HCC stage, extrahepatic metastases and postoperative recurrence. It seems very likely that MCM7 may be applied as a new molecular target in HCC prevention and treat-ment.

Expression of epidermal fatty acid-binding protein in cross-species hepatocellular carcinoma / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To evaluate the utility of the cross-species screening strategy for investigating key molecule(s) involved in onset and progression of hepatocellular carcinoma (HCC).</p><p><b>METHODS</b>HCC-related molecule data from our previous studies and in the literature were collected to establish a cross-species dataset. Tissue samples of HCC, non-HCC surrounding liver (para-HCC), and normal liver that were collected from humans, tree shrews and rats. The genes reported to have the most differential expression in HCC were verified by analyzing the mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively.</p><p><b>RESULTS</b>The cross-species dataset of HCC-related molecules included four genes: epidermal fatty acid-binding protein (E-FABP), liver (L)-FABP, tyrosine a-ketoglutarate transaminase (TKT), and cytokeratin (CK8). In humans, E-FABP mRNA expression was significantly higher (P less than 0.05) in HCC (0.87+/-0.14 vs. para-HCC: 0.64+/-0.12 and normal liver: 0.67+/-0.07; F=20.910). Similar results were obtained in tree shrew (HCC: 0.87 +/- 0.25 vs. para-HCC: 0.73 +/- 0.19 and normal liver: 0.68+/-0.19; F=3.807) and rat (HCC: 0.97+/-0.22 vs. para-HCC: 0.78+/-0.16 and normal liver: 0.80 +/- 0.13; F=4.482). The Western blotting analyses revealed a similar statistically significant trend.</p><p><b>CONCLUSION</b>The cross-species screening strategy for tumor genes may represent a feasible and convenient process of identifying key molecule(s) for human HCC. E-FABP may be a particularly crucial molecule for hepatocarcinogenesis.</p>

Factors influencing long-term hepatitis B virus infection of the tree shrew (Tupaia belangeri chinensis) as an in vivo model of chronic hepatitis B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To determine the methods for establishing an in vivo model of long-term hepatitis B virus (HBV) infection in the Chinese tree shrew (Tupaia belangeri chinensis).</p><p><b>METHODS</b>Seventy-seven neonate (1-3 days old) and 49 young adult (2 weeks to 1 year old) tree shrews were inoculated with different HBV sources (chronic hepatitis B (CHB) human patient serum, single or pooled; HBV-infected tree shrew serum, single only; HBV-infected HepG2.2.15 cells' culture medium supernatant; HBV genome-transfected HepG2.2.15 cells' culture medium supernatant) through various routes of injection (subcutaneous, intraperitoneal, and direct liver via abdominal skin; adults also received intravenous and indirect liver via spleen). Serum and liver biopsies were collected from the animals at various time points post-inoculation for detection of HBV markers by fluorescence quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, time-resolved immunofluorescence, Southern blotting, dot blotting, immunohistochemistry, and microscopy.</p><p><b>RESULTS</b>Among the neonatal group of tree shrews, six (7.8%) were confirmed as HBV-infected for more than 72 (up to 228) weeks after inoculation and another seven (9.1%) were suspected of persistent infections. None of the young adult tree shrews developed persistent infection. Inoculation with single-source serum from either CHB humans or tree shrews were responsible for the most cases of infections, and the subcutaneous injection produced more infections than the other inoculation routes. The most reliable methods of determining HBV infection status were detection of serum HBV immunoreactive markers and intrahepatic HBV DNA.</p><p><b>CONCLUSION</b>In order to establish an in vivo model of CHB in the tree shrew, the animals should be inoculated in the neonatal period using subcutaneous injection.</p>

Effects of Ginkgo biloba extract on biomarker expressions during aflatoxin B_1-induced hepatocarcinogenesis in Wistar rats / 肿瘤

Objective:To study the effect of Ginkgo biloba extract (EGb761) on metabolism of aflatoxin B_1(AFB_1) in Wistar rats. Methods:Seventy one Wistar rats were divided into three groups at random: group A (AFB_1 group), group B (AFB_1+EGb761 group), and group C (control group). The rats in groups A and B were given AFB_1(intraperitoneal injection, 100-200 μg/ kg body weight, 1-3 times/week). The rats in group B were fed the food containing EGb761 while the rats in groups A and C were given normal food. Blood samples were collected and liver biopsy was performed on the 14th, 28th and 42nd week. All the rats were sacrificed at the 64th week. The incidence of hepatoma was observed. The hepatic phase Ⅰ drug-metabolizing enzyme CYP450 and phase Ⅱ enzyme GST were detected by spectrometry. The serum AFB_1-lysine adduct was determined by high performance liquid chromatography (HPLC). The expression of 8-hydroxydeoxyguanosine(8-OHdG) was measured by immunohistochemistry. Results:The incidence of hepatocellular carcinoma (HCC) in group B was significantly lower than that in group A (26.92% vs 76.00%,P<0.001). No hepatocellular carcinoma developed in group C. EGb761 had no effects on the activities of CYP450 and GST in rat liver tissues. The level of AFB_1-lysine adduct reached the peak (4 356.01 pg/mg albumin) at the 14th week in group A. EGb761 significantly inhibited the formation of AFB_1-lysine adducts in serum by 13.07% at the 14th week (P＝0.033), and 73.63% at the 42nd week (P＝0.002). The expression of 8-OHdG protein in rat liver tissues in group B was significantly lower than that in group A at the 28th, 42nd, and 64th week (P<0.05). Conclusion:The main mechanism underlying the effect of EGb761 in blocking hepatogenesis induced by AFB_1 may not be fully related with its influence on the activity of liver phase Ⅰ and phase Ⅱ metabolizing enzymes. EGb761 inhibites the production of AFB_1-lysine addcuts, decreases the expression of 8-OHdG protein, and finally alleviates the DNA oxidative injury, which may be one of the mechanisms for the effects of EGb761 in inhibiting or delaying hepatogenesis induced by AFB_1.

Role of sphingosine 1-phosphate receptor signaling in hematopoietic stem/progenitor cell transmigration / 南方医科大学学报

<p><b>OBJECTIVE</b>To determine the role of sphingosine 1-phosphate receptor (S1PRs ) signaling in CD34+ hematopoietic stem/progenitor cell transmigration.</p><p><b>METHODS</b>CD34(+) cells were separated by Ficoll density gradient centrifugation and incubated in DMEM medium with 10% fetal calf serum. The cells were pretreated by FTY720, with or without pertussis toxin (PTX) and antiCXCR4 mAb in the medium, followed by addition of 100 ng/ml SDF-1 into the lower chamber of a Costar 24-well transwell. The migrated cells were counted using FACS and the migrating rates were determined. The expressions of sphingosine 1-phosphate receptors were analyzed in CD34(+) cells before and after the transmigration by reverse transcriptase- polymerase chain reaction (RT-PCR). Cord blood CD34(+) cells were treated with or without FTY720 (10(+) mol/L), and the expressions of CD49d (VLA-4), CD11a (LFA-1), and CD62L (L-selectin) were analyzed at 1, 8, and 16 h after the treatment.</p><p><b>RESULTS</b>While FTY720 did not affect spontaneous migration, a substantial increase of SDF-1-induced transmigration was observed in the presence of FTY720 (15.26 2.14 to 28.64 2.37). The FTY720-enhanced transmigration was completely blocked by addition of PTX or antiCXCR4 mAb. S1p1-5 was expressed in fresh isolated cord blood CD34(+) cells. The migrating cells stimulated by FTY720 and SDF-1 only expressed S1P1, S1P3, and S1P4. The expressions of CD49d, CD11a and CD62L on CD34(+) cells treated with FTY720 remained unchanged at the selected time points as compared with the control.</p><p><b>CONCLUSIONS</b>S1PRs are involved the transmigration of CD34(+) cells. The activation of S1PRs results in increased chemotactic response of CD34(+) to SDF-1. These effects are mediated through CXCR4 and PTX-sensitive Gi proteins. Only the CD34(+) cells expressing the specific receptors can rapidly transmigrate. The activation of the S1PRs does not affect the expressions of the adhesion molecules on cord blood CD34(+) cells.</p>

Long-term observation of hepatitis B virus (HBV) replication in new-born tree shrews inoculated with HBV / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To observe the hepatitis B virus (HBV) replication in the tree shrews that were inoculated with HBV at neonatal period.</p><p><b>METHODS</b>Six new-born tree shrews were inoculated with human HBV positive serum. Blood samples and liver biopsies were collected at different time points after inoculation. The HBV infection markers were tested by nested polymerase chain reaction (nPCR), fluorescence quantitative polymerase chain reaction (FQ-PCR), Southern blot, ELISA and immunohistochemistry staining. The liver tissues were observed under electron and light microscope.</p><p><b>RESULTS</b>48 weeks after inoculation, HBV DNA and HBV cccDNA were detected in the serum and liver samples of three animals (number 1, 2 and 6) by nPCR. The copy-numbers of HBV DNA detected by FQ-PCR in their serum and liver samples were 103 and-104/ml respectively,and the total DNA in 1microg liver tissue was 107-108. Southern blot indicated that HBV replication intermediates such as HBV cccDNA and HBV ssDNA was detectable in liver tissues. HBsAg was detected by ELISA, and immunohistochemical staining showed a gradual increase of HBsAg-positive liver cells. High copy number of HBV DNA and suspected HBV EM particles could be detected in the liver samples from one of the three animals that have survived more than 2 years after inoculation. The other three animals showed low HBV DNA copy number, and the rest of the signs of HBV infection were negative or transiently positive.</p><p><b>CONCLUSIONS</b>Neonatal tree shrews can be infected with human HBV. HBV can replicate inside the liver cells of tree shrew.</p>

Differentially expressed proteins in the precancerous stage of rat hepatocarcinogenesis induced by diethylnitrosamine / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To screen the differentially expressed proteins especially at the precancerous stage of diethylnitrosamine (DEN) induced hepatocarcinogenesis by comparative proteome research.</p><p><b>METHODS</b>Rats were divided into normal and DEN groups and sacrificed periodically. The liver samples were stained with gamma-glutamyl transpeptidase (GGT) and HE to distinguish the preneoplastic lesion (pre-HCC) from the normal and HCC tissues. The two-dimensional electrophoresis (2-DE) and mass spectrometry (MALDI-TOF-MS/MS) were then applied to analyze the differentially expressed protein between pre-HCC and normal tissues, pre-HCC and HCC, as well as HCC and normal tissues. A few of the candidate proteins such as laminin receptor 1 (67LR) and agmatinase were validated by Western blot and RT-PCR.</p><p><b>RESULTS</b>Totally, there were 82 proteins that differentially expressed two fold or more in one kind of tissues sample than the other, 47 of which occurred in the pre-HCC tissues. Eight proteins including 67LR were consistently up-regulated from normal tissue to pre-HCC and then to HCC tissues, while 22 proteins including agmatinase showed progressively down-regulated in these tissues samples.</p><p><b>CONCLUSION</b>The protein expression profiles are different during the process of hepatocarcinogenesis. Further study on the differentially expressed protein, especially these upregulated in the precancerous stage such as 67LR and agmatinase, might contribute to prevention and early diagnosis of human HCC.</p>

Relationship between Beijing genotypes of Mycobacterium tuberculosis and drug-resistant phenotypes / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the distribution of the Beijing genotypes of Mycobacterium tuberculosis (M. tuberculosis) and the relationships between Beijing genotype strains and drug-resistant phenotypes in China.</p><p><b>METHODS</b>Clinical isolates were collected during a 9-month research period from April to December in 2008 in six geographic regions of China. One isolate that had been biochemically confirmed to be a member of the M. tuberculosis complex was collected from each patient. The demographic data of the patients (eg. sex, age, and history of tuberculosis) as well as the drug resistance patterns and sources of the clinical isolates were collected. Drug susceptibility testing was performed using proportion method. Beijing genotypes of M. tuberculosis were identified by spacer oligonucleotide typing or insertion of IS6110 in the genomic dnaA-dnaN locus.</p><p><b>RESULTS</b>Among the 410 M. tuberculosis clinical isolates, 67.1% (275/410) isolates were Beijing genotypes of M. tuberculosis. Significantly larger proportions of tuberculosis patients were infected with Beijing genotypes in the northeastern regions of China than that of in the central-western regions (chi2 = 20.50, P = 0.000). No significant associations were found either between Beijing genotype strains and patients' age, sex, or treatment history. Multidrug-resistant isolates and rifampin-resistant isolates were more common among Beijing genotype strains than among non-Beijing strains (P = 0.002, P = 0.005).</p><p><b>CONCLUSIONS</b>About two third of the clinical isolates of M. tuberculosis in China are Beijing genotypes. Beijing genotype strains are not correlated with patients' age, sex, treatment history. People living in the northeastern regions of China are more susceptible to Beijing genotypes than those living in the central-western of China. Beijing genotype strains tend to be rifampin-resistant or multidrug-resistant.</p>