Study on growth characteristics of under different conditions and its toxicity / 浙江大学学报·医学版

OBJECTIVE@#To investigate the characteristics of growth and metabolism and the toxicity of under different conditions.@*METHODS@#We observed the growth of and under routine culture conditions and in different pH and salt concentrations, and compared their activities of sugar fermentation using microbiochemical reaction tubes. Four-week-old nude mice were randomized into infection group (=5), infection group (=5) and control group (=5) for intragastric administration of 0.3 mL suspension the two (5×10 cfu/mL) or 0.3 mL normal saline. Samples of the liver, kidney, intestine, feces and blood were taken for analysis of the distribution and toxicity of by fungal culture and histopathological examination.@*RESULTS@# exhibited logarithmic growth at 8-24 h after inoculation and showed stable growth after 24 h. showed optimal growth within the pH value range of 5-7 with a growth pattern identical to that of . grew better than in media containing 5% and 10% NaCl, and could ferment glucose, sucrose, trehalose and sorbitol. could be isolated from the feces, blood, liver and kidney of infected nude mice, and the liver had the highest fungal load (5.7 log cfu/g). could cause pathological changes in the liver and intestine of the mice, but with a lesser severity as compared with .@*CONCLUSIONS@# exhibits optimal growth in mildly acidic or neutral conditions with a high salt tolerance, and can potentially penetrate the intestinal barrier into blood and lead to tissue injuries in hosts with immunosuppression.

Study on growth characteristics of under different conditions and its toxicity / 南方医科大学学报

OBJECTIVE@#To investigate the characteristics of growth and metabolism and the toxicity of under different conditions.@*METHODS@#We observed the growth of and under routine culture conditions and in different pH and salt concentrations, and compared their activities of sugar fermentation using microbiochemical reaction tubes. Four-week-old nude mice were randomized into infection group (=5), infection group (=5) and control group (=5) for intragastric administration of 0.3 mL suspension the two (5×10 cfu/mL) or 0.3 mL normal saline. Samples of the liver, kidney, intestine, feces and blood were taken for analysis of the distribution and toxicity of by fungal culture and histopathological examination.@*RESULTS@# exhibited logarithmic growth at 8-24 h after inoculation and showed stable growth after 24 h. showed optimal growth within the pH value range of 5-7 with a growth pattern identical to that of . grew better than in media containing 5% and 10% NaCl, and could ferment glucose, sucrose, trehalose and sorbitol. could be isolated from the feces, blood, liver and kidney of infected nude mice, and the liver had the highest fungal load (5.7 log cfu/g). could cause pathological changes in the liver and intestine of the mice, but with a lesser severity as compared with .@*CONCLUSIONS@# exhibits optimal growth in mildly acidic or neutral conditions with a high salt tolerance, and can potentially penetrate the intestinal barrier into blood and lead to tissue injuries in hosts with immunosuppression.

Impact of cessation of antiviral therapy at delivery on postpartum liver function in mothers with chronic hepatitis B virus infection / 中华肝脏病杂志

Objective@#To investigate the impact of immediate cessation of antiviral therapy on postpartum liver function and the factors influencing postpartum abnormality in mothers with chronic hepatitis B virus infection.@*Methods@#A retrospective cohort study was conducted. One hundred eighty-eight pregnant women with HBV DNA level > 2×106 IU/ml were enrolled from June 2014 to June 2018. Demographic information and clinical data of liver function and HBV DNA load during gravidity, intrapartum and postpartum period were collected. According to the antiviral treatment recommendations during pregnancy, the women were divided into three groups, namely, tenofovir (TDF), telbivudine (LdT) and control group. Liver function abnormalities among the three groups were compared within 6 months after delivery, and the factors influencing abnormal liver function were analyzed by unconditional logistic regression.@*Results@#Of the 188 cases, 72 cases were in the TDF group, 80 cases in the LdT group, and 36 cases in the control group. Pregnant women in the TDF and LdT groups received oral TDF (300 mg/d) and LdT (600 mg/d) from 28 ± 4 weeks of gestation till delivery. Among the 188 patients, 30 (16.0%) had abnormal postpartum liver function abnormality. The incidence of postpartum liver function abnormality [alanine aminotransferase (ALT) > 2 × upper limit of normal (ULN)] in the TDF, LdT, and control groups was 19.4%, 12.5%, and 16.7%, respectively. The postpartum peak levels of ALT (median, range) in the three groups were 34.5 (12.0-946.0) U/L, 37.5 (12.0-733.8) U/L, and 39.0 (7.0-513.0) U/L, respectively. There was no significant difference between the two indexes among the three groups (P > 0.05). There was no statistically significant difference in the degree of postpartum liver function abnormalities between the three groups (P = 0.944). Most of the liver function abnormalities were mild to moderate (2 × ULN≤ALT < 10 × ULN), and usually resolved spontaneously or by treatment. Univariate and multivariate analysis showed that baseline ALT level during pregnancy was an independent factor associated with postpartum liver function abnormality (OR = 1.031, CI 95%: 1.005-1.058; χ2 = 5.340, P = 0.021), whereas age, antiviral therapy, HBeAg-positivity, baseline HBV DNA levels, gravidity, parity, preterm delivery and delivery mode were not significantly associated with postpartum liver function abnormality.@*Conclusion@#Cessation of antiviral therapy after delivery did not significantly increase the risk of postpartum liver function abnormality in pregnant women with chronic HBV infection. The ALT level during pregnancy is a factor influencing postpartum liver function abnormality.

Research on the mechanism of benzothiazole derivative BD960 on T cell proliferation / 医学研究生学报

Objective Benzothiazole derivative BD960 has immunosuppressive activity after cell -based assays for high-throughput screening.The paper aimed to investigate the involved mechanism of BD960 on T cell proliferation. Methods Human peripheral blood T-lymphocytes were isolated and purified by the immunomagnetic microbeads.Then the T cells were activated by anti-CD3/anti-CD28 mAbs or alloantigen.The effect of BD960 on activa-ted T cell proliferation, the cytotoxic effect BD960 on resting T cells and the expression of activated T cells marker CD25 were measured by flow cytometer.Cytokine levels, including IL-2, IL-4, IL-6, IL-10, IL-17A and IFN-γ, were determined by ELISA. Results BD960 significantly inhibited the proliferation of T cells stimulated by anti-CD3/anti-CD28 mAb or alloantigen in a dose-dependent manner.The IC50 value is (2.3 ±0.3)μmol/L or (2.5 ±0.3)μmol/L, respectively.Moreover, BD960 had no obvious cytotoxic effects on rest-ing T cells and peripheral blood mononuclear cells, even at a high concentration ( up to 100μmol/L) .The ratio of CD25 expression on T cell was 69.7%after stimulated by Anti-CD3/CD28 mAbs with 72 h, the concentration (0.625、2.5、10)μmol/L of BD960 also had no potent effects on the ratio, but 0.1μmol/L FK506 could inhibit CD25 expression as low as 9.4%.The G0/G1 phase of activated T cells was 58.5%after stimulated by BD960 with 96 h.BD960 could induce cell cycle arrest at the G0/G1 phase in activated T cells with the increase of concentration and RAPA in the concentration of 0.1 μmol/L was 91.5%.In addition, BD960 (0.625、2.5、10)μmol/L could inhibit the secretion of IFN-γ, IL-6 and IL-17 in activated T cells with the increase of concentration, without any effects on the secretion of IL-2, IL-4 and IL-10. Conclusion BD960 not only exerts the inhibition on the late stage of T cell activation of cell proliferation but also inhibits the secretion of inflammatory cytokines, such as IL-6, IL-17 and IFN-γ, while the mechanism of BD960 on T cell proliferation was not the same as FK506.As a result, BD960 has the potential to be the lead compound to develop a new immunosuppressant.

Inhibitory effect of small molecule compound BD691 on activated T cell proliferation and its mechanism / 医学研究生学报

Obej ctive Abnormal proliferation of T cells plays an important role in the development of autoimmune diseases. The article aimed to study the inhibitory effect of small molecule compound BD691 on T cell proliferation and its mechanism. Methods Human peripheral blood T-lymphocytes were isolated and purified by the immunomagnetic microbeads,then T cells were ac-tivated with anti-CD3/CD28 mAbs or alloantigen.The inhibitory effect of BD691 on activated T cell proliferation, the cytotoxic effect BD891 on resting T cells and the expression of activated T cells marker CD25 were measured by flow cytometry.Furthermore, ELISA was used to detect the secretion of cytokines associated with T cell differentiation. Results BD691 significantly inhibited the prolif-eration of T cells being stimulated by anti-CD3/CD28 mAb or alloantigen in a dose-dependent manner, and IC50 values are (8.5 ± 1.5)μmol/L and (7.2 ±1.3)μmol/L, respectively.However, BD691 had no obvious cytotoxic effects on resting T cells and periph-eral blood mononuclear cells, even at a high concentration ( up to 100μmol/L) .In T cells which were not activated by anti-CD3/CD28 mAb, the percentage of CD25+T cells is only 1.6%of the total cells, while the number increased to 68% after activating treatment.Mean-while, in T cells which were activated by 0, 3.3, 10, 30μmol/L BD691, no obvious change of CD25 expression were observed, while immunosuppressant FK506 (0.1μmol/L) significantly decreased the expression of CD25 +T cells (14.9%).In unactivated T cells, 95.6%cells were at G0/G1 phase, while after activation, the percentage of cells at G0/G1 phase reduced to 57.7%.In addition, BD691 inhibited the secretion of IFN-γ, IL-6 and IL-17 in activated T cells, but had no effects on the secretion of IL-2, IL-4 and IL-10. Co nclusion BD691 exerts no effects on T cell activation, but it inhibits T cell proliferation by inducing T cell cycling arrest at G0/G1 phase.Moreover, BD691 inhibits the secretion of key cytokines (such as IFN-γ, IL-6, IL-17) closely related to the differ-entiation of Th1 and Th17 cells.The results suggest that BD 691 is a potential lead compound to develop a new immunosuppressant for the inhibition of abnormal proliferation and differentiation of T cells.

Morphology of bacterial flora in root canals associated with apical abscesses / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Apical abscess is an inflammatory process in the peri-radicular tissues caused by biofilms in the necrotic root canal systems. Therefore, a comprehensive analysis of the bacterial colonization is required for a better understanding of the pathogenesis. This study aimed to investigate the patterns of bacterial infection of root canals of teeth with apical abscesses and to determine whether histological and microbiological findings correlated with clinical conditions.</p><p><b>METHODS</b>Eighteen samples from 18 teeth with apical pathological lesions were analyzed. Nine patients with acute apical abscesses experienced severe pain, and nine patients were asymptomatic with a sinus tract. After extraction, each affected root was divided into two halves. One half was processed for histobacteriologic analysis and examined using light microscopy, and the other half was analyzed using scanning electron microscopy (SEM) to determine the patterns of microbial colonization of the root canals.</p><p><b>RESULTS</b>The appearance of each sample subjected to SEM was consistent with the histobacteriologic findings despite the presence or absence of clinical symptoms. Intraradicular biofilms comprising cocci, rods, and/or filaments of amorphous materials were observed in the apical third of the main root canals in all samples. The bacterial biofilms covering the main root canal walls also penetrated the dentinal tubules to varying depths. The morphologies of biofilms varied, and a unique pattern of intraradicular infection was not identified.</p><p><b>CONCLUSION</b>Intraradicular infections formed complex and variable multispecies biofilms and their presence did not correlate with clinical symptoms.</p>

Comparison of biological and genetic background of CA16 between different epidemic strains / 中华微生物学和免疫学杂志

ObjectiveTo study the biological characterization and the genetic background of circulating CA16 strains in mainland of China for the purpose of CA16 vaccine development in the future.MethodsCA16 strains were isolated from throat swabs of patients with hand-foot-mouth disease and identified by neutralization assay and RT-PCR.The genotype of these isolates were determined by sequence alignment and phylogenetic analysis of VP1 gene.The proliferation dynamics and the plaque morphology were observed when propagated in Vero cells.The pathogenicity of these CA16 isolates was evaluated by challenging newborn mice.ResultsIn this study,six CA16 circulating isolates,BJ-1-6 were obtained.The RT-PCR products were 150 bp amplified with the general enterovirus primers and 210 bp with CA16 primers respectively,which cannot be amplified by EV71 primers.Additionally,these isolates were identified to display some obvious proliferation dynamics and plaque morphology when propagated for 96 h in Vero cells.The diameter of plaques were about 1.5 to 2 mm for BJ-1,BJ-2,BJ-4,BJ-6,4-5 mm for BJ-3 and 3 mm for BJ5,the plaques were regular except BJ-3.All the six isolates can be neutralized by the convalescent serum of patient infected with CA16.The virus titer of different isolates propagated for five passages in Vero cells was 7.0LgCCID50/ml.The sequence alignment of VP1 gene demonstrated that the genotypes of BJ-2,BJ-4,BJ5 were C1 and BJ-1,BJ-3,B J-6 were C,3 comparatively.The genetic distance of the VPI gene from theseisolates suggested that they were highly genetic identity with the homology of 90％ in nucleotide and 99％ in dedicated amino acid respectively.However,a distinctive difference in pathogenic ability in neonatal mice was found that the suckling mice challenged with BJ-3 & BJ-5 were paralyzed 4-5 d and dead 6-7d postchallenge,compared with the control group without any abnormality in the during of 14 d.ConclusionThe circulating CA16 isolates in China have different biological characteristics,different pathogenic ability and similar genetic backgrounds,which is helpful for the development of a CA16 vaccine in the future.

A clinical evaluation of new type of rotary nickel-titanium instrument Mtwo for seniles in root canal therapy / 实用口腔医学杂志

To evaluate the clinical effects of rotary nickel-titanium instruments Mtwo in root canal therapy in the aged patients. Using step-back technique,80 teeth with pulpal and periapical involvement were instrumented by Mtwo in the M group, and by K file in the K group. Mtwo could keep the original curvature and flow of the root canals. No transportation, apical blockage, ledge or perforation was found in the M group. There was more complications in the K group than in the M group.The operative time was shorter and posttreatment pain seldom occurred in the M group. With rotary NiTi instruments Mtwo for seniles' root canals treatment, root canals can be prepared effectively and quickly,and is worth of clinical application.

Construction and identification of infectious full-length cDNA clone of enterovirus 71 / 中华微生物学和免疫学杂志

Objective To construct an infectious full-length cDNA clone of enterovirus 71(EV71)and develop a technological platform for study on vaccine development as well as molecular virology of EV71.Methods According to the nucleotide sequence of EV71 strain 085 isolated in China,four pairs of primers were designed for amplification of four end to end overlapping subgenomic cDNA fragments,the cDNA fragments were directional cloned into pBluescript SK(+)vector,and the virus genome cDNA clone was obtained by ligation orderly.The rescued virus of parental strain 085 from RNA transfected host cells was identified by RT-PCR,IFA,titration as well as transmission electron microscope(TEM)after the transcription of the full-length cDNA clone in vitro.Results The full-length cDNA clone was constructed successfully,and the typical CPE was observed after its transcription into Vero cells.The rescued virus with 20-30 nm in diameter can not only be neutralized by EV71 special anti-serum but also react with anti-EV71 monoclonal antibody that virus infected cells stained with FITC can be detected by IFA.After amplification from the total RNA extraction of virus infected cells by RT-PCR with EV71 special primers,the 226 bp products can be detected.The growth curve showed that the rescued virus can propagate in Vero cells stably with a titer of 4.5 ～6.0 lgCCID50/ml during 8 passages.The plaque formed by rescued virus is identical as parental virus in morphology but smaller in size.Conclusion An infectious full-length clone of EV71 was developed successfully,which will be used for further study on pathogenesis and vaccine development of EV71.

A comparative study of antimicrobial efficacy of three different instruments and mechanical preparation techniques in single infected root canals / 实用口腔医学杂志

Objective: To compare and analyze the antimicrobial efficacy of three different mechanical preparation techniques in single infected root canals. Methods; Forty-five single root canals with chronic periapical periodontitis were selected. The specimens were divided into three groups randomly, 15 root canals per group. Croup A: preparation with stainless steel K-files (step-back technique), Croup B: preparation with HERO 642 NiTi rotary files (crown-down technique) and Group C: preparation with Mtwo NiTi rotary files ( modified crown-down technique). The sterile normal saline was used as irrigation. Samples were taken before and after canal preparation. The difference of CFU was calculated as well as the bacterial species. Results; All groups were effective to reduce bacteria within the infected root canals greatly(P<0.01). Croup A and Group C were statistically better than Group B(P<0.05). Group A was more effective than Group C but there was no statistically difference between them(P>0.05). Conclusion; Mechanical preparation can greatly reduce the intracanal bacteria, but can not obtain bacteria-free canals. The mechanical preparation must be aided by chemical irrigation to improve the success of root canal therapy.

Patterns of Enterococcus faecalis in infected root canals: An in vitro study / 北京大学学报(医学版)

Objective:To establish an in vitro root canal model infected by Enterococcus faecalis and to observe the morphology, distribution and relative position of Enterococcus faecalis in infected root canals.Methods: Ten human healthy premolars extracted for orthodontic reasons were collected. Following sterilization , a total of 5 specimens were aseptically transferred to separate Eppendorf tubes containing 1. 5 mL brain-heart infusion broth (BHI) inoculated with 0.1 mL Enterococcus faecalis suspension that had been adjusted to Mcfarland 5, and were incubated at 37℃ for 21 days. The other 5 specimens were as controls. The roots of all specimens were then split into two halves along the mesiodistal axis. One half was processed with light microscopic ( Brown & Brenn stain) to check the bacteria in dentinal tubules, and the other was observed with SEM to investigate the bacterial status in infected root canals. Results: Enterococcus faecalis could penetrate into the dentinal tubules about 330-1 000μm. A dense bacterial aggregation composed of Enterococcus faecalis and amorphous matrix was observed in the apical third of the root canals, whereas Enterococcus faecalis were seen free-floating or planktonic in the crown and middle third of the root canals . No microorganisms were found in the root canals of the controls. Conclusion:Enterococcus faecalis could form bacterial biofilm on the root canal walls and penetrate into the dentinal tubules. The in vitro model designed was simple, and had good practicability to make a further comparative evaluation of various antimicrobial methods in the reduction of intracanal bacteria.

Patterns of Enterococcus faecalis in infected root canals:An in vitro study / 北京大学学报(医学版)

Objective:To establish an in vitro root canal model infected by Enterococcus faecalis and to observe the morphology,distribution and relative position of Enterococcus faecalis in infected root canals.Methods: Ten human healthy premolars extracted for orthodontic reasons were collected.Following sterilization,a total of 5 specimens were aseptically transferred to separate Eppendorf tubes containing 1.5 mL brain-heart infusion broth(BHI) inoculated with 0.1 mL Enterococcus faecalis suspension that had been adjusted to Mcfarland 5,and were incubated at 37 ℃ for 21 days.The other 5 specimens were as controls.The roots of all specimens were then split into two halves along the mesiodistal axis.One half was processed with light microscopic(Brown & Brenn stain) to check the bacteria in dentinal tubules,and the other was observed with SEM to investigate the bacterial status in infected root canals.Results: Enterococcus faecalis could penetrate into the dentinal tubules about 330-1 000 ?m.A dense bacterial aggregation composed of Enterococcus faecalis and amorphous matrix was observed in the apical third of the root canals,whereas Enterococcus faecalis were seen free-floating or planktonic in the crown and middle third of the root canals.No microorganisms were found in the root canals of the controls.Conclusion: Enterococcus faecalis could form bacterial biofilm on the root canal walls and penetrate into the dentinal tubules.The in vitro model designed was simple,and had good practicability to make a further comparative evaluation of various antimicrobial methods in the reduction of intracanal bacteria.

Bacterial biofilm on the apical external root surfaces of human teeth associated with chronic periradicular lesions / 北京大学学报(医学版)

Objective:To investigate the patterns of microbial infection on the apical external root surfaces of treated and untreated teeth associated with chronic apical periodontitis and to study bacteria in the biofilm in order to find out the species,constitution and origination of bacteria in periapical biofilm.Methods: Ten teeth with chronic apical periodontitis from patients of the Department of Stomatology of People's Hospital,Peking University: 5 untreated teeth with a radiographically visible chronic periradi-cular lesions and 5 teeth with extensive carious lesions,radiolucent lesions of varying sizes and attached periradicular tissues were selected for study.Using aseptic techniques and sterile instruments,bacterial samples of the root canals were taken,inoculated and separated according to usual practice.After extraction,ten teeth were fixed and the apical 5 mm portion of one root was sectioned.Root tips were dehydrated,sputter coated with gold,and then examined for the occurrence of bacteria on the apical root surfaces using scanning electron microscope.Five healthy teeth with vital pulp were used as controls.Results: Microbial study showed that ten specimens yielded bacterial growth.The most prevalent bacteria were P.micros and F.nueleatum.In the 5 untreated teeth,bacterial cells were usually observed close to the apical foramen in only 1 specimen.Morphologically,these bacteria consisted of cocci.In the 5 treated teeth,a dense bacterial aggregation composed mainly of cocci and rods was observed surrounding the apical foramen of all specimens.Besides rods,other bacterial morphological types were recognized,including coaggregations of cocci and filaments,characterizing a fully developed "corn-cob".No microorga-nisms were found in the healthy controls.Conclusion:Bacterial biofilm was always present in teeth with post-treatment endodontic disease.The presence of apical bacterial biofilm is clinically important,and it may cause failure of endodontic treatment as a consequence of persistent infection.