An enzyme-linked immunosorbent assay (ELISA) for the measurement of antibodies to different parts of the gram-negative lipopolysaccharide core region

Bovine serum albumin was complexed with the core antigens of either Escherichia coli J5 LPS, Salmonella minnesota R595 LPS or E. coli lipid A. These core-BSA complexes were used for solid-phase coating in ELISAs for anti-core antibodies. Antibodies, binding to various parts of the core region were easily quantified in a single experimental set-up, which was hitherto not possible. The ELISA has only 3 incubation steps and is not costly as only moderate amounts of the core antigens (i.e., 1 microgram per test) were needed for coating. The sensitivity proved to be excellent and the complexes were biologically fully active (compared to native, smooth LPS), which make them suitable for the screening (after fusion) of monoclonal anti-core antibodies. Another possible application is the large-scale screening of blood-bank sera in order to find samples with a high anti-core antibody content.     

Tissue cages for study of experimental streptococcal infection in rabbits. I. Production of erythrogenic toxins in vivo

Tissue cages implanted subcutaneously were used to infect rabbits with erythrogenic toxin (ET) producing streptococci. The in-vivo production of ET was followed during the infection by immunoprecipitation analyses of the tissue cage fluid (TCF). ET types A and C were mainly detected during the first week of infection, but, as late as 4 weeks after the inoculation, ET was occasionally found in TCF. The nonspecific mitogenic activity of ET on human lymphocytes was also used as a biological marker to recognize ET in TCF. Mitogenic activity was detected in 90% of samples during the first week. In order to characterize the mitogenic material released by growing streptococci, TCF was electrofocused in polyacrylamide gel. The eluates of sliced gels were checked for mitogenic activity and compared with a purified ET preparation containing ET types A and C. It could be verified that ET type A was produced under in-vivo conditions by strains NY-5 and SF130, while ET type C was produced by strain T18. Differences between production of toxins in vitro and in vivo might be of significance for the understanding of the pathogenetic mechanisms in streptococcal infection.     

异基因外周血干细胞的动员,检测及临床移植的应用研究

目的：探讨异基因外周血干细胞移植（ａｌｌｏ－ＰＢＳＣＴ）供者经Ｇ－ＣＳＦ或Ｇ－ＣＳＦ＋ＧＭ－ＣＳＦ动员后,采集的外周血干细胞（ＰＢＳＣ）移植物中的幼稚粒细胞与单个核细胞（ＭＮＣ）、ＣＤ３４＾＋细胞及ＣＦＵ－ＧＭ之间的相关性和移植的剂量标准及临床应用效果。方法：对１１例ａｌｌｏ－ＰＢＳＣＴ供者用Ｇ－ＣＳＦ（９例）或Ｇ－ＣＳＦ＋ＧＭ－ＣＳＦ（２例）进行动员,于动员前及动员后,分别对外周血及ＭＮＣ惧物中的幼稚粒细胞、ＣＤ３４＾＋细胞及ＣＦＵ－ＧＭ进行检测计数,预处理方法主要用大剂量环磷酰胺（ＣＴＸ）＋全身照射（ＴＢＩ）。结果：动员后外周血中的幼稚粒细胞与ＣＤ３４＾＋细胞及ＣＦＵ－ＧＭ同步增加,外周血ＭＮＣ中的幼稚粒细胞数与ＣＤ３４＾＋细胞数及ＣＦＵ－ＧＭ有较好的相关性。１１例患者全部植活和恢复造血功能,并为染色体核型     

Helicobacter hepaticus infection in BALB/c mice abolishes subunit-vaccine-induced protection against M. tuberculosis

BCG, the only licensed vaccine against tuberculosis (TB), provides geographically variable protection, an effect ascribed to exposure to environmental mycobacteria (EM). Here we show that altering the intestinal microbiota of mice by early-life infection with the commensal bacterium Helicobacter hepaticus (Hh) increases their susceptibility to challenge with Mycobacterium tuberculosis (Mtb). Furthermore Hh-infected mice immunised parenterally with the recombinant subunit vaccine, human adenovirus type 5 expressing the immunodominant antigen 85A of Mtb (Ad85A), display a reduced lung immune response and protection against Mtb challenge is also reduced. Expression of interleukin 10 (IL10) messenger RNA is increased in the colon of Hh infected mice. Treatment of Hh-infected Ad85A-immunised mice with anti-IL10 receptor antibody, following challenge with Mtb, restores the protective effect of the vaccine. These data show for the first time that alteration of the intestinal microbiota by addition of a single commensal organism can profoundly influence protection induced by a TB subunit vaccine via an IL10-dependent mechanism, a result with implications for the deployment of such vaccines in the field.     

Management Options for Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is associated with diverse pathophysiologic mechanisms. These mechanisms include increased abnormal colonic motility or transit, intestinal or colorectal sensation, increased colonic bile acid concentration, and superficial colonic mucosal inflammation, as well as epithelial barrier dysfunction, neurohormonal up-regulation, and activation of secretory processes in the epithelial layer. Novel approaches to treatment include lifestyle modification, changes in diet, probiotics, and pharmacotherapy directed to the motility, sensation, and intraluminal milieu of patients with IBS. Despite recent advances, there is a need for development of new treatments to relieve pain in IBS without deleterious central or other adverse effects.     

ANTI-ALLERGIC EFFECTS OF SANGUISORBA OFFICINALIS ON ANIMAL MODELS OF ALLERGIC REACTIONS

ABSTRACT

We investigated the effect of aqueous extract of Sanguisorba officinalis L.(Rosaceae) root (SOAE) on the immediate-type allergic reactions in vivo and in vitro. SOAE (0.01 to 1 g/kg) inhibited systemic allergic reaction induced by compound 48/80. When SOAE was employed in a systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. SOAE (0.001 to 1 g/kg) dose-dependently inhibited passive cutaneous anaphylaxis (PCA) activated by anti-dinitrophenyl (DNP) IgE. SOAE (0.001 to 1 mg/mL) also dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cyclic AMP (cAMP) in RPMC, When SOAE was added, significantly increased compared with that of normal control. Moreover, SOAE (0.01 to 1 mg/mL) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-α (TNF-α) production. These results suggest that SOAE may be beneficial in the regulation of immediate-type allergic reaction.     

Early childhood caries screening tools: a comparison of four approaches

BackgroundEarly childhood caries (ECC) is prevalent and consequential. Risk assessment tools have been proposed that can be used to identify children who require intensive interventions. In this study, the authors compare four approaches for identifying children needing early and intensive intervention to prevent or minimize caries experience for their accuracy and clinical usefulness.MethodsThe authors screened 229 predominantly low-income Hispanic children younger than 3 years with ECC and 242 without ECC by using the American Academy of Pediatric Dentistry's Caries-risk Assessment Tool (CAT) and the optional screening measure of culturing Streptococcus mutans. The authors compared four approaches (CAT, CAT minus socioeconomic status, CAT minus socioeconomic status plus mutans streptococci [MS] and MS alone) for accuracy and clinical usefulness.ResultsThe results of the CAT demonstrated high sensitivity (100.0 percent) and negative predictive value (NPV) (100.0 percent) but low specificity (2.9 percent) and positive predictive value (PPV) (49.4 percent). The MS culture alone had the highest combination of accuracy and clinical usefulness (sensitivity, 86.5 percent; specificity, 93.4 percent; PPV, 92.5 percent; NPV, 87.9 percent). When we removed the socioeconomic status element, the CAT's performance improved.ConclusionsSalivary culture of MS alone in a population of young, low-income Hispanic childrenoutperformed the CAT and variations on the CAT for test accuracy (sensitivity and specificity) and clinical usefulness (predictive values).Clinical ImplicationsScreening for ECC by using salivary MS cultures and variations on the CAT are promising approaches for identifying children who need early and intensive intervention to prevent or minimize caries experience.     

Demonstration of In Vitro Host-Guest Complex Formation and Safety of para-Sulfonatocalix[8]arene as a Delivery Vehicle for Two Antibiotic Drugs

The macrocycle para-sulfonatocalix[8]arene, sCX[8], was examined with 2 antibiotic drugs, ciprofloxacin (CIP) and isoniazid. The drugs were shown to form complexes with sCX[8] using proton nuclear magnetic resonance, thermogravimetric analysis, fluorescence spectroscopy, and molecular modeling. Both drugs form 1:1 hydrated (H₂O: 13%-14% w/w) host-guest complexes, with sCX[8] binding around the pyridine ring of isoniazid, and around the piperazine and cyclopropane rings of CIP. From proton nuclear magnetic resonance, the binding constant of isoniazid to sCX[8] was 6.8 (±0.3) × 10³ M^?1. Addition of 2 equivalents of sCX[8] to CIP resulted in a 58% decrease in fluorescence, and time-resolved fluorescence anisotropy of CIP doubles with sCX[8]. Each drug binds into the cavity of the macrocycle, with binding stabilized via combinations of hydrogen bonding, electrostatic interactions, π-π stacking, and hydrophobic effects. The safety of sCX[8] was examined in vitro with human embryonic kidney 293 cells. The IC₅₀ of sCX[8] was 559 μM, which is a minimum of 5-fold higher than the concentration that would be used in the clinic. The in vitro effect of sCX[8] on the action of CIP was examined on a panel of bacterial lines. The results showed that sCX[8] has no inherent antibiotic activity and had no negative effect on the action of CIP.     

Effect of residual doxycycline concentrations on resistance selection and transfer in porcine commensal Escherichia coli

Pig feed may contain various levels of antimicrobial residues due to cross-contamination. A previous study showed that a 3% carry-over level of doxycycline (DOX) in the feed results in porcine faecal concentrations of approximately 4?mg/L.The aim of this study was to determine the effect of residual DOX concentrations (1 and 4?mg/L) in vitro on selection of DOX–resistant porcine commensal Escherichia coli and transfer of their resistance plasmids.Three different DOX–resistant porcine commensal E. coli strains and their plasmids were characterised. These strains were each brought in competition with a susceptible strain in a medium containing 0, 1 and 4?mg/L DOX. Resistant bacteria, susceptible bacteria and transconjugants were enumerated after 24?h and 48?h.The tet(A)–carrying plasmids showed genetic backbones that are also present among human E. coli isolates. Ratios of resistant to susceptible bacteria were significantly higher at 1 and 4?mg/L DOX compared with the blank control, but there was no significant difference between 1 and 4?mg/L. Plasmid transfer frequencies were affected by 1 or 4?mg/L DOX in the medium for only one of the resistance plasmids.In conclusion, DOX concentrations of 1 and 4?mg/L can select for resistant E. coli in vitro. Further research is needed to determine the effect of these concentrations in the complex environment of the porcine intestinal microbiota.