Rapid detection of Actinobacillus actinomycetemcomitans using a loop-mediated isothermal amplification method

INTRODUCTION: Actinobacillus actinomycetemcomitans has been implicated in the etiology of aggressive periodontitis. In this study, we applied a novel nucleic acid amplification method, called loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions, allowing the rapid detection of A. actinomycetemcomitans. METHODS: We designed the primers for detecting A. actinomycetemcomitans and evaluated the specificity and sensitivity of the assay. RESULTS: The LAMP primers used in this study successfully amplified serotypes a-e of A. actinomycetemcomitans, while other oral bacteria were not amplified. By measuring the precipitation of magnesium pyrophosphate, we could quantify the chromosomal DNA of A. actinomycetemcomitans. The detection limits using the real-time turbidimetry analysis were 5.8 x 10(2)-5.8 x 10(7) copies of A. actinomycetemcomitans template DNA per reaction tube. In addition, the LAMP assay was used for the rapid detection of A. actinomycetemcomitans in clinical specimens from eight individuals. The results with the LAMP method were similar to those using conventional polymerase chain reaction. CONCLUSION: Our results suggest that the LAMP-based assay is very useful for the rapid detection of A. actinomycetemcomitans.     

Lotka's law and the pattern of scientific productivity in the dental science literature

Statistical regularities can be observed in many natural and social phenomena. From empirical data on the authorship of scientific papers, Lotka deduced an inverse-square law: the number of authors publishing n papers is 1/n2 of those publishing one paper. The general type for the relation (1/n(c)) has a wide range of applicability to a variety of phenomena. This study examined, by means of bibliometric tools, whether Lotka's law could be applied to the literature of dental science. Data came from 20 leading dental science journals, as reported in Journal Citation Reports. The search was performed with a programme developed using Visual Basic for Applications, which counted the number of authors and analysed their contributions to the literature. Authorship for all contributions, as reported in Medline, was compiled for each of these 20 journals for the last 25 years, 1971 through 1995. The total number of authors was 43,796, responsible for 124,556 authorships. The journals published in countries other than the USA exhibited higher degrees of author concentration. The dental science literature conformed very well to Lotka's model with c = 1.95.     

Selective expansion of donor‐derived regulatory T cells after allogeneic bone marrow transplantation in a patient with IPEX syndrome

IPEX syndrome is a rare and fatal disorder caused by absence of regulatory T cells (Tregs) due to congenital mutations in the Forkhead box protein 3 gene. Here, we report a patient with IPEX syndrome treated with RIC followed by allogeneic BMT from an HLA‐matched sibling donor. We could achieve engraftment and regimen‐related toxicity was well tolerated. Although the patient was in mixed chimera and the ratio of donor cells in whole peripheral blood remained relatively low, selective and sustained expansion of Tregs determined as CD4+CD25+Foxp3+ cells was observed. Improvement in clinical symptoms was correlated with expansion of donor‐derived Tregs and disappearance of anti‐villin autoantibody, which was involved in the pathogenesis of gastrointestinal symptoms in IPEX syndrome. This clinical observation suggests that donor‐derived Tregs have selective growth advantage in patients with IPEX syndrome even in mixed chimera after allogeneic BMT and contribute to the control of clinical symptoms caused by the defect of Tregs.     

Second allogeneic hematopoietic SCT for relapsed ALL in children

A second SCT is generally accepted as the only potentially curative approach for ALL patients that relapse after SCT, but the role of second SCT for pediatric ALL is not fully understood. We performed a retrospective analysis of 171 pediatric patients who received a second allo-SCT for relapsed ALL after allo-SCT. OS at 2 years was 29.4±3.7%, the cumulative incidence of relapse was 44.1±4.0% and non-relapse mortality was 18.8±3.5%. Relapse occurred faster after the second SCT than after the first SCT (117 days vs 164 days, P=0.04). Younger age (9 years or less), late relapse (180 days or more after first SCT), CR at the second SCT, and myeloablative conditioning were found to be related to longer survival. Neither acute GVHD nor the type of donor influenced the outcome of second SCT. Multivariate analysis showed that younger age and late relapse were associated with better outcomes. Our analysis suggests that second SCT for relapsed pediatric ALL is an appropriate treatment option for patients that have achieved CR, which is associated with late relapse after the first SCT.     

Locoregional adoptive immunotherapy resulted in regression in distant metastases of a recurrent esophageal cancer

 Esophageal cancer is one of the most common malignant diseases. However, postoperative recurrences are still resistant to currently available radiochemotherapy. We recently reported a study on the initial clinical efficacy of locoregional adoptive immunotherapy for advanced esophageal cancer. We report here our clinical experience of remarked responses in distant metastatic lesions in a patient with recurrent cancer after receiving this immunotherapy. A male patient underwent curative surgery, and presented with multiple recurrent metastases in the supraclavicular lymph nodes (LNs), liver, and abdominal aortic LNs. Autologous tumor-activated lymphocytes (AuTLs) generated ex vivo were regionally injected into supraclavicular LNs every 2 weeks 13 times. Mean numbers of the administrated cells were 0.8 × 10⁹ cells/injection. AuTLs established from peripheral blood lymphocytes stimulated by autologous tumor cells with interleukin-2 were tested for their cytotoxicity before every treatment. During immunotherapy, Grade 2 diarrhea and fever were observed. The clinical partial responses were obtained in all lesions and were sustained for 11 months. Because clinical toxicity was tolerable, this immunotherapy might be useful for patients with far-advanced esophageal cancers. Received: June 19, 2002 / Accepted: September 26, 2002 Correspondence to:U. Toh     

Characterization of rat monoclonal antibodies against human beta-defensin-2

Defensins are a family of cationic antimicrobial peptides that participate in host defense. Human beta-defensin (hBD)-2 has a potent bactericidal activity against a wide spectrum of microorganisms. Because human gingival epithelium is constantly exposed to a variety of microbial challenges, it is considered that hBD-2 has an important role in the protective mechanisms against oral bacterial infection. However, little is known about the production of hBD-2 in tissues of the oral cavity. Six rat monoclonal antibodies (MAbs) raised against chemically synthesized hBD-2 have been characterized. Rat MAbs were specific for the conformational epitopes on hBD-2, but not to hBD-1. To identify the epitope on hBD-2, a series of six overlapping peptides covering the hBD-2 whole sequence were synthesized and the immunoreactivities of six MAbs were examined. The FCPRRYK domain in hBD-2 was recognized by all six MAbs and suggested to be an epitope region. By immunocytochemistry, hBD-2 was localized focally in the epidermis of the human gingival tissue using the MAbs. The MAbs specifically recognized against hBD-2 will be a useful tool to study the functional role of antimicrobial agents and an important asset in the imaging of oral infection processes.