Kenichi Sato

Use of the MALDI BioTyper system with MALDI–TOF mass spectrometry for rapid identification of microorganisms

In a clinical diagnosis microbiology laboratory, the current method of identifying bacterial isolates is based mainly on phenotypic characteristics, for example growth pattern on different media, colony morphology, Gram stain, and various biochemical reactions. These techniques collectively enable great accuracy in identifying most bacterial isolates, but are costly and time-consuming. In our clinical microbiology laboratory, we prospectively assessed the ability of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI–TOF MS) to identify bacterial strains that were routinely isolated from clinical samples. Bacterial colonies obtained from a total of 468 strains of 92 bacterial species isolated at the Department of Clinical Laboratory at Chiba University were directly placed on target MALDI plates followed by addition of CHCA matrix solution. The plates were then subjected to MALDI–TOF MS measurement and the microorganisms were identified by pattern matching with the libraries in the BioTyper 2.0 software. Identification success at the species and genus levels was 91.7% (429/468) and 97.0% (454/468), respectively. MALDI–TOF MS is a rapid, simple, and high-throughput proteomic technique for identification of a variety of bacterial species. Because colony-to-colony differences and effects of culture duration on the results are minimal, it can be implemented in a conventional laboratory setting. Although for some pathogens, preanalytical processes should be refined, and the current database should be improved to obtain more accurate results, the MALDI–TOF MS based method performs, in general, as well as conventional methods and is a promising technology in clinical laboratories.

Closure of oroantral communications using a pedicled buccal fat pad graft

PURPOSEnThis report evaluates the use of a pedicled buccal fat pad graft for closure of oroantral fistulae.nnnMATERIALS AND METHODSnFourteen patients with oroantral communications, ranging from 8 to 20 mm in diameter, were treated by the use of a pedicled buccal fat pad graft.nnnRESULTSnThe procedure was successful in 13 of 14 patients. Postoperatively, the orally exposed fat gradually was transformed into a granulation-like tissue and epithelization developed within 3 weeks.nnnCONCLUSIONnIt was concluded that the procedure has wide application and a high degree of success.

Evidence for two distinct tumor-suppressor gene loci on the long arm of chromosome 11 in human oral cancer.

Loss of heterozygosity (LOH) on human chromosome 11 has been reported in a variety of human cancers. To search for the existence of tumor‐suppressor gene(s) associated with oral squamous cell carcinoma (SCC) on chromosome 11, we have performed high‐resolution deletion mapping in 31 patients with oral SCC using 22 microsatellite markers for this chromosomal region. LOH was observed in 14 of 25 cases (56.0%) that were informative with at least one locus. Most allelic deletions detected in our study were specific to the long arm of the chromosome. Furthermore, the data presented here show 2 distinct, commonly deleted regions. The first region, with frequent LOH, was restricted between markers D11S939 and D11S924 separated by 3 centimorgans (cM) on chromosome 11q23. The second region of common deletion was identified between markers D115912 and D11S910, separated by 7 cM at 11q25. Our results suggest that at least 2 tumor‐suppressor genes involved in the development of oral SCC are present on the long arm of chromosome II.

Treatment of ameloblastoma in children.

Clinicopathological data were collected for six children with ameloblastoma less than 16 years old. They were all treated initially by conservative surgery and satisfactory results without jaw deformities were finally attained. One of the histological characteristics of ameloblastoma in children is the prevalence of the plexiform type, which is thought to behave less aggressively than the follicular type. Conservative treatment is acceptable initial treatment of ameloblastoma in children who can be followed up in a precise, detailed manner.

Statistical observation of osteosarcoma of the maxillofacial region in Japan. Analysis of 114 Japanese cases reported between 1930 and 1989.

In Japan 114 cases of osteosarcoma of the maxillofacial region have been reported during the past 60 years. The average age at the onset of the disease in this region was about one or two decades later than that of osteosarcoma of other regions. Females were affected more frequently (59.6%) than males (40.4%). The mandible was more frequently affected (58.8%) than the maxilla (41.2%). Swelling was the conspicuous symptom for osteosarcoma of the maxillofacial region. Most patients received surgical treatment with or without radiation and chemotherapy; however, the prognosis is poor, regardless of the type of treatment.

Gingival squamous cell carcinoma in a patient with chronic graft-versus-host disease

This article describes a gingival squamous cell carcinoma that developed in a 21-year-old woman who received a bone marrow transplant at the age of 16 from her human leukocyte antigen-identical sister as treatment for severe aplastic anemia. Thirty days after transplantation, she presented with cutaneous erythema as a result of acute graft-versus-host disease, and this subsequently evolved into chronic graft-versus-host disease. A lichenoid white plaque of the gingiva developed shortly thereafter, and it began to increase in size rapidly 4 years posttransplantation. Biopsy indicated squamous cell carcinoma arising in this region, apparently associated with chronic graft-versus-host disease. Few reports have described a secondary solid malignancy involving the oral cavity of young adults after bone marrow transplantation.

Detection of human papillomavirus in head and neck tumors with DNA hybridization and immunohistochemical analysis

The presence of human papillomavirus (HPV) DNA in oral, sinus, pharynx, and larynx lesions of Japanese patients was studied by Southern blot hybridization under less stringent (25% formamide, 42 degrees C) and stringent (50% formamide, 42 degrees C) conditions. Three samples from 10 benign tumors, and 3 of 30 malignant tumors, contained HPV DNA or HPV-related sequences. The HPV DNAs harbored in three laryngeal papillomas were HPV-11, -6, and -6 or -11, respectively. The HPV DNA and viral capsid antigens were easily detected by in situ hybridization, Western blotting, and peroxidase-antiperoxidase staining. However, neither the typical restriction pattern of HPV DNA nor viral antigen was identified in the malignant tumors, suggesting that subgenomic fragments remained integrated in the host cell DNA.

Gingival metastasis from primary hepatocellular carcinoma: report of a case and review of literature.

Observation dune femme de 78 ans. Le foie navait pas ete identifie comme siege de tumeur primaire tant que la metastase gingivale navait pas ete diagnostiquee

Rapid identification of microorganisms by mass spectrometry: improved performance by incorporation of in-house spectral data into a commercial database

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used as a microbial diagnostic method for species identification of pathogens. However, MALDI-TOF identification of bacteria at the species level remains unsatisfactory, with the major problem being an incomplete database that still needs refinement and expansion. Augmentation of the original MALDI BioTyper 2.0 (Bruker) database by incorporating mass spectra obtained in-house from clinical isolates may increase the identification rate at the species level. We conducted a prospective study to assess whether the augmented database can improve the performance of MALDI-TOF MS for routine identification of species. Cluster analyses revealed distinct differences in MS spectral profiles of clinical isolates obtained in our hospital and those of ATCC strains in the Bruker database. In the first part of the study, which was performed over 3xa0weeks, 259 bacterial isolates were subjected to analysis by MALDI-TOF MS, and MS spectra of 229 successfully identified isolates (49 species) were incorporated into the original database to give the augmented Bruker–Chiba database. In a second separate analysis, the concordance of identification of 498 clinical isolates of the 49 species with conventional methods was 87.1% (434/498) with the commercial Bruker database and 98.0% (488/498) using the Bruker–Chiba database. These results indicate that refinement of a commercial database can be achieved relatively easy and effectively by incorporating MS spectra of clinical isolates obtained in a clinical laboratory.

Moesin is a possible target molecule for cytomegalovirus-related Guillain-Barré syndrome

Objective: Previous histochemical studies in the demyelinating form of Guillain-Barré syndrome (GBS), acute inflammatory demyelinating polyneuropathy (AIDP), have shown complement deposition on the surface of Schwann cells, and therefore unknown epitopes would be present on the outer surface of Schwann cells. Methods: We used a proteomic-based approach to search for the target molecules of AIDP in the extracted proteins from schwannoma cells. Sera were obtained from 40 patients with GBS, 31 controls with inflammatory disease, and 46 normal controls. Results: We found that patients with AIDP after cytomegalovirus (CMV) infection have serum autoantibodies against membrane-organizing extension spike protein (moesin), which is expressed in the Schwann cell processes at the nodes of Ranvier and is crucial for myelination. Of the 40 patients with GBS, 6 had recent CMV infection and 5 of them (83%) had high levels of serum immunoglobulin G antibodies against moesin. The anti-moesin antibodies were found in none of the control subjects with disease including 5 with CMV infection but no neuropathy, and only 2 (4%) of the 46 normal control subjects. Immunocytochemistry showed that moesin was stained at the distal tips of schwannoma cells by sera from the patients with CMV-related AIDP but not by sera from controls. Conclusion: Moesin is a possible immunologic target molecule of pathogenic autoantibodies in patients with CMV-related AIDP. Classification of evidence: This study provides Class II evidence that levels of serum anti-moesin antibodies accurately distinguishes CMV-related AIDP from non–CMV-related AIDP (sensitivity 83%, specificity 93%).