[Activation of endoplasmic reticulum stress and its effect on osteogenic differentiation induced by micropit/nanotube topography].

Objective: To explore the activation of endoplasmic reticulum stress (ERS) in bone marrow mesenchymal stem cell (BMMSC) and its effect on osteogenic differentiation induced by micropit/nanotube topography (MNT), so as to provide guidance for the topography design of biomaterials. Methods: Four sample groups were fabricated: polishing control group (polished titanium, PT, no treatment), thapsigargin treatment (TG, 0.1 µmol/L TG treated for 9 h), MNT5 and MNT20 (anodized at 5 V and 20 V after acid etching). Scanning electron microscope (SEM) was used to observe the topography of Ti samples. The alkaline phosphatase (ALP) production, collagen secretion and extracellular matrix (ECM) mineralization of BMMSC (osteogenic induced for 7, 14 and 21 d) on Ti samples were detected to evaluate the osteogenic differentiation. After 12 h incubation, the shape and size of ER was examined using a transmission electron microscope (TEM), and ERS-related genes including immunoglobulin heavy chain binding protein (BiP), protein kinase RNA-like endoplasmic reticulum kinase (PERK) and activating transcription factor 4 (ATF4) were detected by quantitative real-time PCR (qRT-PCR). Results: After 7, 14 and 21 d of induction, the ALP production, collagen secretion and ECM mineralization in TG and MNT20 all significantly increased compared to PT (P<0.05). The cells grown on TG, MNT5 and MNT20 surfaces displayed gross distortions of the ER. Compared to PT, BiP, PERK, ATF4 mRNA expression in TG was respectively 1.87±0.10, 2.24±0.35, 1.85±0.14; BiP, ATF4 mRNA expression in MNT5 were respectively 1.27±0.09, 1.25±0.04; BiP, PERK, ATF4 mRNA expression in MNT20 were respectively 1.44±0.09, 2.40±0.60, 1.48±0.05 (P<0.05). Conclusions: MNT triggered different degree of ERS, and the activated ERS may promote MNT-induced osteogenic differentiation.

Detection of acute HIV infections among sexually transmitted disease clinic patients: a practice in Guangxi Zhuang Autonomous Region, China.

Detection of people with acute HIV infection (AHI) affords an important opportunity for early HIV treatment and prevention. HIV RNA reverse transcriptase-polymerase chain reaction (RT-PCR) testing with two-stage pooling scheme was used to detect the AHI in specimens collected from sexually transmitted disease (STD) clinic patients in Guangxi, China. A total of 246 HIV RNA tests were required to screen 11 395 samples negative for conventional enzyme immunoassay (EIA) and Western blot assays, and five AHI cases (0.04%, 95%CI 0.02% to 0.10%) with a high viral load (median of 265,677 copies per ml) were detected. The total expenditure for RT-PCR testing reflected an added cost of $2.9 per specimen screened and $6575 per additional case of AHI identified among the study population. This study supports the feasibility of pooled RNA testing in addition to detection of HIV infections among patients at STD clinics in China, but the cost effectiveness should be carefully considered.

Trypanosoma congolense infections: MHC class II-restricted immune responses mediate either protection or disease, depending on IL-10 function.

BALB/c mice are highly susceptible and C57BL/6 relatively resistant to Trypanosoma congolense infections. Here we show that relatively resistant wild-type B6 mice infected with T. congolense survive significantly longer (> 200 days) than infected major histocompatibility complex (MHC) class II-deficient B6 mice (approximately 50 days). We also show that blocking of the interleukin-10 (IL-10) receptor induces early death of wild-type B6 mice infected with T. congolense (approximately 10 days), but does not affect the survival of infected MHC class II-deficient B6 mice. We conclude that MHC class II-restricted immune responses mediate protection and, when IL-10 function is impaired, MHC class II-restricted immune responses mediate early mortality in otherwise resistant B6 mice. Thus, in T. congolense infections, MHC class II-restricted immune responses mediate either protection or disease, depending on IL-10 function.

Experimental African trypanosomiasis: lack of effective CD1d-restricted antigen presentation.

BALB/c mice are highly susceptible to African trypanosomiasis, whereas C57BL/6 mice are relatively resistant. Other investigators have reported that the synthesis of IgG antibodies to purified membrane form of variant surface glycoprotein (mfVSG) of Trypanosoma brucei is CD1 restricted. In this study, we examine the role of the CD1d/NKT cell pathway in susceptibility and resistance of mice to infection by African trypanosomes. Administration of anti-CD1d antibodies to Trypanosoma congolense-infected BALB/c mice neither affects the parasitemia nor the survival time. Correspondingly, CD1d(-/-) and CD1d(+/+) BALB/c mice infected with T. congolense or T. brucei show no differences in either parasitaemia or survival time. The course of disease in relative resistant C57BL/6 mice infected with T. congolense is also not affected by the absence of CD1d. Parasitaemia, survival time, and plasma levels of IgG2a and IgG3 parasite-specific antibodies in infected CD1d(-/-) C57BL/6 are not different from those of infected CD1d(+/+) C57BL/6 mice. We conclude that CD1d-restricted immune responses do not play an important role in susceptibility/resistance of mice infected with virulent African trypanosomes. We speculate that virulent trypanosomes have an evasion mechanism that prevents the induction of a parasite-specific, CD1d-restricted immune response by the host.

Clinic-based evaluation of Clearview Chlamydia MF for detection of Chlamydia trachomatis in vaginal and cervical specimens from women at high risk in China.

OBJECTIVES: To determine the performance of a rapid Chlamydia trachomatis (CT) test (Clearview Chlamydia MF) compared to the current "gold standard" (Roche Amplicor CT assay) test, and to assess acceptability of the tests to patients. METHODS: A total of 1497 women at sexually transmitted diseases (STD) clinics or re-education centres in six urban cities (Shanghai, Nanjing, Shenzhen, Guangzhou, Chengdu and Fuzhou) in China participated in the study. Three vaginal and three cervical swabs were collected from each participant. Rapid CT tests were performed locally on the first vaginal and cervical swabs and the results were read independently by two staff members. The second and third swabs were randomised for performing the Roche CT assay at the National STD Reference Laboratory. Acceptability of the rapid tests to patients was determined by asking patients in clinics about their willingness to wait for the results. RESULTS: The prevalence of CT was 13.2% (197/1497), as determined by the Roche assay with cervical specimens. CT was detected in 78 vaginal and 127 cervical specimens by the rapid test and the positive rates determined with cervical specimens were significantly higher than those with vaginal specimens (p<0.001). There was good agreement between the results read by two independent staff for either vaginal or cervical specimens (both kappa = 0.98, p<0.001). Sensitivities for vaginal and cervical specimens were 32.8% and 49.7%, respectively, and specificities were 99.2% and 97.9%, respectively. The positive predictive value was 85.7% for vaginal and 78.4% for cervical specimens. The vast majority of the patients (99.1%) were willing to wait up to two hours for the results. CONCLUSION: Clearview Chlamydia MF, while yielding a rapid result and requiring minimal laboratory facilities, had unacceptably low sensitivity compared to a nucleic acid amplification test. Rapid tests yielding results within one hour are generally accepted by the clients.

In vivo expression profiles of cytokine and iNOS mRNAs in rats infected with Eimeria separata.

Studies on cytokine (IFN-gamma, IL-2, IL-4, IL-5, IL-10) and inducible NO-synthase (iNOS) gene transcription in mesenteric lymph nodes (MLN) and the caecum wall were performed 0, 48, and 72h after primary and challenge infections of rats with Eimeria separata using RT-PCR. The amount of IFN-gamma mRNA was elevated in MLN and caeca 72h after primary and 48-72h after challenge infection when compared with uninfected controls. Increased amounts of IL-2 mRNA were only found in MLN of infected rats 72h post-infection (p.i.). In case of IL-10, infections did not affect the amount of mRNA in MLN, but led to markedly increased levels in the caecum wall of both infected groups 48 and 72h p.i. Levels of IL-4 mRNA remained unchanged after infections and IL-5 gene transcripts were undetectable. Amounts of iNOS mRNA (not investigated in MLN) were found strongly enhanced 48 and 72h p.i. in the caecum walls of all infected animals when compared with naive controls. The data are discussed in regard of the cellular source of the cytokines and their immunological role.

Immunity in rats against Eimeria separata: oocyst excretion, effects on endogenous stages and local tissue response after primary and challenge infections.

The aim of the study was the characterization of the local immune response of Lewis rats to Eimeria separata, a caecum-dwelling coccidium. Rats infected twice at 10-day intervals with 5,000 oocysts developed a high degree of immunity to a heavy challenge with 100,000 oocysts, reducing the oocyst production by > 98% when compared with naive recipients. Histopathological investigations performed over a period of 0-72 h post-infection (pi) showed that 1st generation schizonts, developed within 24 h pi, represented the major target stages, although later stages were also affected. Preinfected animals showed significantly more lymphocytes in the caecum wall than naive animals. An increase in lymphocyte numbers after challenge observed in both groups was enhanced in challenged animals up to 36 h pi. The number of lamina propria lymphocytes predominantly was increased after primary infection whereas in repeatedly infected animals the increase also concerned intraepithelial lymphocytes. In addition, the numbers of plasma cells were enhanced in the caecum wall of immune animals. Macrophage infiltration in the caecum wall followed a similar time course in both groups up to 36 h pi. A subsequent further rise up to 48 h pi was enhanced in naive rats. Tissue infiltrations with eosinophils and mast cells were observed predominantly in the repeatedly infected rats. No obvious changes occurred with intestinal neutrophils and goblet cells. In conclusion, caecum tissue alterations suggest an early local immune response, which is related to development and maturation of the parasite.

The susceptibility testing of 13 strains of Mycobacterium leprae to rifampicin and the determination of minimal effective dosage.

By use of the mouse footpad technique, the susceptibility testing of 13 strains of Mycobacterium leprae to rifampicin (RFP) and the determination of minimal effective dosage (MED) were carried out. Among these strains of M. leprae, 8 were obtained from previously untreated multibacillary leprosy patients and 5 from relapsed leprosy patients without using RFP previously. The results showed that the MED of all strains to RFP were less than or equal to 0.001% FRP in the diet, 5 strains being equal to 0.001%, 5 less than or equal to 0.0001%, 2 greater than or equal to 0.0003% and 1 less than or equal to 0.0003%. The results indicated that the MED value of RFP could be lower than that of other reports. Because the critical concentration of RFP for assessment of RFP-resistant strains is not well established a further study would be worthwhile. The results of the determination of sera RFP concentrations in mice administered the RFP diet were identical with that of Holmes' report. Five of the 13 strains also showed that the growth of bacilli were suppressed by 10 mg/kg RFP using the gavage method.

Preliminary observations on experimental leprosy in tupaias (Tupaia belangeri yunalis).

The Tupaia belangeri yunalis (tree shrew) is one of the primitive primates. They were inoculated subcutaneously in the footpad or intravenously with Mycobacterium leprae from a patient with multibacillary leprosy. As controls, the footpads of CFW mice were inoculated with the same suspension of M. leprae. The results showed growth of acid-fast bacilli (AFB) in the footpads of locally inoculated CFW mice and in the footpads of both locally and intravenously inoculated tupaias. Whereas the numbers of AFB declined in the footpads of CFW mice after 12 months, they increased in the tupaia footpads, up to 2.44 x 19(9) AFB/g of tissue. The footpads of one tupaia were swollen, which on section revealed a granulomatous infiltration, including foamy and heavily infected macrophages. M. leprae were also seen in the branches of cutaneous nerves. Also AFB occurred in some viscera. Preliminary studies indicate that the AFB multiplying in tupaias are M. leprae.