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T Miyagi

Publications and source records attributed to T Miyagi.

157 records · Page 9Linked to original sources
PubMedDate not supplied

Studies on the most efficient vector systems for gene transduction into dendritic cells.

Specialized antigen-presenting cells (APC), known as dendritic cells (DC), play a pivotal role in initiating primary immune responses. Several vector systems, including adenoviral vectors, retroviral vectors, hemagglutinating virus of Japan-related vectors, and the electroporation, have been shown to transduce genes into mouse and human but not rat DC. However, there is no direct evidence to support the view that the currently used vector systems are able to transduce genes into mature DC. Inasmuch as most, if not all, gene transfer studies investigating DC or DC-related cell populations are performed employing heterogeneous-groups of cells, it is therefore important to determine the extent to which gene transduction occurs in bona fide DC. In this study, we provide evidence that none of these vector systems are able to transfer genes into mature rat DC, which are derived from bone marrow cells (BMC), driven by Flt3/Flk2 ligand and IL-6, and purified with CD161a. Nevertheless, the most efficient gene transduction was observed with developing DC progenitor cells during long-term culture of rat BMC. Successful gene transfer was achieved after 2-week culture with an HIV-based lentiviral vector system.

Animals↗
PubMedDate not supplied

Presence of Streptococcus infection in extra-oropharyngeal head and neck squamous cell carcinoma and its implication in carcinogenesis.

To investigate the involvement of S. anginosus infection in head and neck cancer in the extra-oropharyngeal cavity, we analyzed 3 DNA samples prepared from squamous cell carcinoma of the external auditory canal and one from squamous cell carcinoma of the skin using polymerase chain reaction (PCR) analysis and Southern blot analysis to detect the DNA sequence of S. anginosus. We also examined these four specimens by Gram's stain to detect the streptococcal bacterial bodies. By PCR analysis, the DNA sequence of S. anginosus was found in 4 out of 4 (100%) DNA samples obtained from these tumors. By Southern blot analysis, positive bands were detected in one out of the 3 (33%) samples from the tumor taken from the external auditory canal. We detected streptococcal bacterial bodies in one of the three specimens from the tumor obtained from cancer of the external auditory canal and in the one specimen from the skin cancer by the method of Gram's stain. Contrary to our expectations, these bacterial bodies were located in the middle of the tumor. Since S. anginosus is thought to exist in the mouth as a normal flora and to be located mainly in the gingiva and dental plaque, these data strongly indicate that S. anginosus infection is implicated in the carcinogenesis of head and neck squamous cell carcinoma.

Aged↗
PubMedDate not supplied

Loss of heterozygosity of chromosome 9p21 and 7q31 is correlated with high incidence of recurrent tumor in head and neck squamous cell carcinoma.

To examine whether genetic factors influence the prognosis of cancer patients, several polymorphic markers were used to determine the allelic loss of certain areas of the genome. Two polymorphic markers, IFNA and D9S171 were used to study the loss of heterozygosity (LOH) of chromosome 9p21 in 75 head and neck squamous cell carcinomas. LOH was detected in 14 out of 64(22%) DNA samples obtained from cancer specimens when at least one marker was used. The frequency of LOH was not correlated with the localization of the tumor, clinical stage of the patient, tumor size and lymph node involvement. However, the frequency of LOH was significantly higher in the recurrent tumors than in the non-recurrent tumors, suggesting that the allelic loss at 9p21 can be correlated with the short term prognosis of the patients. LOH was identified in only three out of 19(16%) samples when D7S522 was used as a marker. However, all of these three cases were recurrent, and two of the three showed the allelic loss at 9p21 at the same time. These results indicate that LOH of 9p21 and/or 7q31 is a novel prognostic factor independent of other clinical factors for head and neck squamous cell carcinoma. Replication error (RER) was observed in 4 cancers, implicating genetic instability in the carcinogenesis of a subset of head and neck squamous cell carcinoma.

Adult↗
PubMedDate not supplied

Suppression of chemokine-induced chemotaxis of monkey neutrophils and monocytes by chlorinated hydrocarbon insecticides.

Chemokines, characterized as pro-inflammatory chemicals made by the immune system, consist of a family of low molecular weight proteins with potent in vitro chemotactic activity causing leukocyte accumulation in vivo. This study determines the effects of organochlorine pesticide exposure on the chemotactic functions of monkey neutrophils and monocytes, using a 48-well chemotaxis chamber. Chemokines IL-8 (interleukin-8) and RANTES were used as the chemoattractants to induce chemotaxis among these monkey leukocytes. Monkey neutrophils or monocytes were first treated with heptachlor, chlordane or toxaphene for 1 hour at 37 degrees C, and the number of cells migrating toward 200 ng/ml IL-8 (for neutrophils) or 100 ng/ml RANTES (for monocytes) were scored. Inhibition of chemotaxis was seen with all samples after treatment with heptachlor, chlordane and toxaphene at concentrations from as low as 10(-14) M to 10(-5) M. Among the three compounds studied, toxaphene was the least effective in preventing monocytes from migrating toward RANTES. The ability of these pesticides to inhibit chemotaxis did not correlate directly with their potential apoptotic effects on the monkey leukocytes. These studies suggest that exposure to organochlorine pesticides may alter leukocyte-related immune functions.

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