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Biomedical subjects

Y Hosaka

Publications and source records attributed to Y Hosaka.

At least 127 records · Page 7Linked to original sources
PubMed1991

Pentamer arrangements in fragments of human rotavirus inner capsids observed by low dose electron microscopy.

Fragments of disrupted capsids were frequently seen in purified preparations of human rotavirus inner capsids by negative staining method in electron microscopy. The ultrastructures of these fragments were analyzed in comparison with the T = 13L model. Well-resolved pentamers were rarely seen in the fragments on observation at the standard electron doses, but were frequently seen at low electron doses, which meant a better preservation of the steric structure of capsid fragments in the latter case. Thus advantages of low dose electron microscopy have been shown in observation of capsid fragments.

Capsid↗
PubMed1991

Clinical and microbiological study of local minocycline delivery (Periocline) following scaling and root planing in recurrent periodontal pockets.

This study was designed to evaluate the clinical and microbiological effects of local administration of 2% minocycline-HCl ointment (Periocline) combined with scaling and root planing in recurrent periodontal pockets. Thirty-three sites were selected for this examination. The sites had probing depths greater than 5 mm and loss of attachment greater than 2 mm within the previous 3 months. They were assigned as test (22 sites) or control sites (11 sites). After meticulous scaling (SC) and root planing (RP), Periocline was delivered into the periodontal pockets of test sites: control sites were irrigated with biological saline following SC/RP. Administration of Periocline or irrigation with saline was performed once a week for 4 consecutive weeks. The effects on clinical conditions including probing pocket depth, clinical attachment level, and bleeding on probing were evaluated at baseline, 2, 4, 8, and 12 weeks. Microbiological examinations consisting of darkfield microscopic study and culture were performed at baseline, 4, and 12 weeks. Clinical conditions improved in both groups following treatment; significantly better improvements were obtained in the test group. Microbiological study revealed that Periocline effectively eliminated periodontopathic gram-negative bacteria. These results indicated that a combination of SC/RP with local administration of 2% minocycline for recurrent periodontal pockets brought about more satisfactory results than conventional SC/RP.

Administration, Topical↗
PubMed1990

Laser ureterolithotripsy with combined rigid and flexible ureterorenoscopy.

Because the pulsed dye laser can be transmitted through a thin, flexible quartz fiber a small caliber ureteroscope and flexible ureterorenoscope are applicable. Therefore, the use of a rigid or flexible ureterorenoscope was combined with laser lithotripsy to treat upper urinary tract calculi. All 14 ureteral stones below the pelvic brim were removed successfully with a rigid 7.2F (outer diameter) ureteroscope and 14 of 16 stones above the pelvic brim were removed with a flexible ureterorenoscope. Laser monotherapy was effective in 24 cases and the complementary use of forceps or electrohydraulic lithotripsy was required in 4. Two stones were lost from the visual field during endoscopic manipulation. There was no complication requiring surgical correction. The combined use of these instruments is highly successful and safe for the treatment of upper urinary tract calculi.

Adult↗
PubMed1990

HLA-DQ-controlled T cell response to soluble egg antigen of Schistosoma japonicum in humans.

We analysed regulatory mechanisms of the human T cell response to soluble egg antigen (SEA) of Schistosoma japonicum in vitro. SEA is a crude antigen mixture containing numerous epitopes. We obtained SEA-induced T cell lines from five patients with chronic schistosomiasis japonica, and tested their proliferative response to molecular weight fractions of SEA. Although all T cell lines showed strong responses to crude SEA, there was a heterogeneity in fraction-driven responsiveness. All but one T cell line tested failed to respond to SEA fraction I (mol. wt greater than 18 kD). One patient who was typed as HLA-DQw1/w4, did not show proliferation of CD4+ T cells to fraction I; however, a fraction I-driven helper T cell response was observed when we added HU-11 monoclonal antibody specific for HLA-DQw1/w4. This indicated that the patient had helper T cells to the fraction even though their response was suppressed. Because HLA-DQ had an effect on functional expression of suppressor T cells, it was suggested that there was epitope-specific regulation of the T cell response to SEA, and HLA-DQ-controlled immune suppression might be involved in the regulatory system in human chronic schistosome infection.

Animals↗
PubMed1990

Ultrastructural changes during lysis of L929 target cells by class II-restricted influenza virus-specific murine cytotoxic T-lymphocyte clones.

Lysis of virus-infected L929 target cells transfected with the H-2 class II IAk gene by class II-restricted influenza virus-specific murine cytotoxic T lymphocyte (CTL) clones was studied by electron microscopy and compared with lysis of L929 cells by class I-restricted CTL clones. T lymphocytes predominantly approached the basal surface of target cells grown on a plastic dish and also approached uninfected L929 target cells, although virus maturation exhibited no polarity with respect to the cell surface site. After incubation for 30 min, the target cell nuclei began to change: chromatin became irregularly redistributed and aggregated, and the nuclei appeared swollen. Later, electron-dense and -light areas of nuclei became segregated, and the cytoplasm became disorganized with many vacuoles. The ultrastructural changes of target cells during lysis by class I- and class II-restricted CTL clones appeared to be similar. These findings and other cytotoxicity data of class I and class II CTLs are discussed.

Animals↗
PubMed1990

[Histological and flow cytometric analyses of carcinogenesis of rat prostate cancer].

Histological and flow cytometry (FCM) analyses were performed of carcinogenesis of rat prostate cancer induced with N-Nitroso-N-methylurea (NMU). Ten-week-old rats were inoculated intravenously (i.v.) with twice injections of NMU (30 mg/kg body weight) and then, divided into 3 groups; Group 1: the rats were injected subcutaneously with LH-RH analogue (100 micrograms/kg b.w.) every 4 weeks. Group 2: the rats were injected subcutaneously with testosterone enanthate (10 mg/body) every 2 weeks and Group 3: the rats were untreated to serve as controls. We further divided Groups 1 and 2 into (+) and (-) subgroups at 34 weeks after initial injection. Group 1 (+) or 2 (+) rats were continuously given the drug and in Group 1 (-) or 2 (-) rats the drug was suspended. At 44 or 53 weeks after initial injection, we removed the prostate and seminal vesicles of all rats and performed histological and FCM analyses of them. Histological analysis of rat prostates revealed hyperplasia in each group, and both Groups 2 (+) and 2 (-) showed an incidence as high as 87.5%. Atypical hyperplasia was sometimes observed in each group and its incidence was not significantly different between any 2 groups. At 51 weeks after initial injection, a macroscopic adenocarcinoma (weighing about 11 g) was found in the prostate of a dead rat of Group 2 (+). Histological analysis of rat seminal vesicles revealed hyperplasia in each group, in particular in Groups 2 (+) and 2 (-). In these groups all rats showed hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[In situ hybridization study of human papillomavirus from the penile cancer].

The histochemical detection of human papillomavirus (HPV) was performed using the technique of in situ hybridization from the formalin fixed paraffin embedded specimens of penile carcinoma and condylomata+ acuminata . One of 19 penile cancer cases (5.3%) revealed the positive staining on the nuclei of the tumors for HPV type 16/18. However, the positive nuclei were scattered and localized in small part of the tumor which showed no koilocytosis. On the contrary, 11 of 12 condyloma acuminata cases (91.7%) showed positive staining on the nuclei of the tumors for HPV type 6/11, also 5 of the 11 cases (45.5%) revealed cross reaction for other type of HPV. The HPV types 6/11, 16/18 and 31/33/35 may be unrelated to the pathogenesis of the Japanese penile carcinoma. However, further study is necessary to evaluate that the number of HPV-DNA copy in our cases is too small, or the other type of HPV is responsibility.

Adult↗
PubMed1990

Bactericidal effects on subgingival bacteria of irrigation with a povidone-iodine solution (Neojodin).

This study was undertaken to determine the optimal concentration of a povidone-iodine solution (Neojodin: NJD) for irrigation of subgingival pockets. Three different dilutions were prepared (undiluted, 20%, and 10%). Statistically significant reduction of total colony forming units (CFU) was shown after irrigation with undiluted NJD solution when compared to control sites. Although reduction was not significant after irrigation with 20% or 10% NJD solution, total CFU were reduced to less than 1% in several sites, which was not true with biological saline.

Bacteroides↗
PubMed1990

The finest ultrastructural details of the inner layer of rotavirus revealed by minimal electron doses.

The inner layer of human and calf rotavirus ultrastructure was analyzed using minimal doses in transmission electron microscopy. The morphological unit of spontaneously disrupted virions has the aspect of a flower-like structure, and its petals are hexagonally arranged and have a central pin hole. The similar flower appearance can be observed in complete virions and in rotavirus tube structures produced in aged samples of rotavirus kept for more than a year.

Animals↗
PubMed1989

Nuclear deoxyribonucleic acid ploidy in squamous cell bladder cancer.

Flow cytometric analysis of nuclear deoxyribonucleic acid content was performed on 76 primary squamous cell bladder carcinomas treated between January 1970 and December 1975. Patients were followed for a median of 10.1 years. Nuclei were extracted from paraffin-embedded archival material and isolated nuclei were stained with propidium iodide. Of the 76 tumors 73 were evaluable by flow cytometry providing high quality deoxyribonucleic acid histograms: 27 (37 per cent) showed a deoxyribonucleic acid diploid or normal pattern, 17 (23 per cent) exhibited a significant increase in the 4C peak (deoxyribonucleic acid tetraploid) and 29 (40 per cent) showed a distinct aneuploid peak. High grade (grades 3 and 4) and high stage (stages T2 to T4) tumors had a significantly higher incidence of abnormal (either tetraploid or aneuploid) deoxyribonucleic acid patterns than low grade (grades 1 and 2) and low stage (stages Tis/Ta/T1) tumors (p less than 0.005). The 5 and 10-year rate free of disease for patients with deoxyribonucleic acid diploid tumors was 67 per cent compared to 22 and 18 per cent, respectively, for patients with tumors showing abnormal ploidy patterns (p less than 0.0005). At 5 and 10 years after diagnosis an estimated 18 per cent of the patients with deoxyribonucleic acid diploid tumors will die of bladder cancer. In contrast, an estimated 53 per cent of the patients with tetraploid tumors and 82 per cent and 86 per cent of those with aneuploid tumors will die of squamous cell bladder carcinoma by 5 and 10 years after diagnosis (p less than 0.0001). These results demonstrate that nuclear deoxyribonucleic ploidy measured by flow cytometry is an important objective prognostic variable for patients with squamous cell carcinoma of the bladder.

Carcinoma, Squamous Cell↗
PubMed1989

In vivo antitumor mechanism of natural human tumor necrosis factor involving a T cell-mediated immunological route.

We have investigated the in vivo antitumor mechanism of natural human tumor necrosis factor (n-TNF) isolated from a culture of human leukemic B cell line (BALL-1), especially its action as an immunomodulator, and found that the in vivo antitumor effect of n-TNF on Meth A sarcoma implanted in BALB/c mice pretreated with monoclonal antibody against T cell-specific surface antigen (Thy-1) was significantly diminished. Furthermore, when BALB/c mice were treated with T cell subset-specific monoclonal antibodies, anti-L3T4 or anti-Lyt-2.2, the antitumor effect of n-TNF on Meth A sarcoma was significantly reduced. Therefore, it was suggested that the in vivo antitumor mechanism of n-TNF might involve a T cell-mediated immunological route.

Animals↗
PubMed1989

Diagnosis of Fasciola sp. infections in cattle by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was evaluated for diagnosis of experimental or naturally occurring Fasciola sp. infections in cattle. The positive rate for the ELISA in calves inoculated with Fasciola metacercariae were 21.1% by 2 weeks postinoculation (PI), 94.6% by 4 weeks PI and 100% by 6-21 weeks PI. The positive rate for the immunodiffusion test (Ouchterlony test) reached 91.7% by 2 weeks PI, however, it dropped to 77.8% by 10 weeks PI. The positive rate for the fecal egg examination was 0% by 10 weeks PI, 77.8% by 12 weeks PI and 100% by 14-21 weeks PI. The practical application of ELISA was tested by using 165 cows raised under field condition. All the 24 cows that were positive both in the fecal egg examination and the Ouchterlony test were ELISA positive. Of the 6 cows that were egg positive and Ouchterlony negative, 5 showed ELISA positive reactions. Of the 27 cows that were egg negative and Ouchterlony positive, 24 were ELISA positive. Of the 108 cows that were egg negative and Ouchterlony negative, 90 were ELISA negative. However, the other 18 cows had ELISA positive reactions. Our results suggested that the ELISA using crude adult antigen was superior to the Ouchterlony test and fecal egg examination for diagnosis of experimental or naturally occurring Fasciola sp. infections in cattle.

Animals↗
PubMed1989

Disappearance of specific antibodies in patients with chronic schistosomiasis japonica by treatment with praziquantel.

We tested effects of praziquantel, an antischistosomal compound, on clinical and immunological parameters of chronic schistosomiasis japonica. Two Japanese patients, who had high antibody titers to Schistosoma japonicum antigens but no fecal schistosome eggs or no or mild symptoms complained, were treated with praziquantel. Within two years after treatment, anti-schistosome antibodies in sera from the patients became negative in enzyme-linked immunosorbent assay. There was no significant alteration in cellular immunity to the parasite. Although S. japonicum infection is believed to have been eradicated in Japan, our present results seem to suggest the possibility that a few Japanese individuals, who have high anti-schistosome antibody, still harbor live parasites.

Animals↗
PubMed1988

Generation and functional characterization of T cell lines and clones specific for Schistosoma japonicum egg antigen in humans.

T cell lines specific for Schistosoma japonicum egg Ag were established in vitro from patients with chronic schistosomiasis japonica, and investigated their possible immunopathologic roles by testing lymphokines production and in vitro granuloma formation assay. All lines tested had surface phenotypes of CD3+ CD4+ CD8-, and showed S. japonicum soluble egg Ag (SEA)-specific proliferation requiring HLA-DR-restricted Ag presentation. Of these fractions of SEA separated by gel filtration, Fraction II (m.w. 7,000 to 18,000) and III (m.w. 7,000) induced strong proliferation of T cell lines, whereas fraction I (m.w. 18,000+) failed to induce detectable proliferation to any T cell lines tested. One of the T cell lines was cloned by micromanipulation: two of eight clones responded only to fraction II, and six to both fractions II and III. We observed that four of eight clones tested produced IL-2 in response to SEA, and three of them were able to transfer S. japonicum egg-specific granulomatous hypersensitivity in vitro to an HLA haplo-identical individual without previous schistosome infection. These immunopathologic functions of T cell clones seemed to be activated by at least two distinct epitopes of SEA. Our present observations suggest that at least two distinct CD4+ human T cells, both of which recognize epitopes expressed on SEA molecules of less than 18 kDa, might have critical roles in granulomatous hypersensitivity to eggs of S. japonicum in humans.

Adult↗
PubMed1988

Cells process exogenous proteins for recognition by cytotoxic T lymphocytes.

Cells exposed to intact, noninfectious influenza virus were shown to be recognized by class I-restricted anti-influenza cytotoxic T lymphocytes (CTLs). Both internal and external proteins derived from virions were processed by cells for CTL recognition. Sensitization required the inactivation of viral neuraminidase activity and could be inhibited by preventing fusion of viral and cellular membranes. These findings are important in designing vaccines to elicit CTL responses, since they demonstrate that cells can process intact, exogenous proteins for recognition by CTLs and suggest that such processing depends on introduction of exogenous proteins into the cytoplasm.

Animals↗
PubMed1988

Recognition of noninfectious influenza virus by class I-restricted murine cytotoxic T lymphocytes.

We have recently shown that murine target cells can be sensitized for lysis by class I-restricted influenza virus-specific cytotoxic T lymphocytes (CTL) using noninfectious influenza virus. Sensitization is dependent on inactivation of viral neuraminidase activity (which can be achieved by heating virus); and requires fusion of viral and cellular membranes. In the present study, we have examined recognition of antigens derived from heat-treated virus by cloned CTL lines induced by immunization with infectious virus. Target cells sensitized with heat-treated virus were recognized by all 11 CTL clones that were specific for internal virion proteins (nucleoprotein and basic polymerase 1), and by one of six clones specific for the major viral glycoprotein (the hemagglutinin). Immunization of mice with heat-treated virus primed their splenocytes for secondary in vitro CTL responses. CTL generated in this manner recognized target cells infected with recombinant vaccinia virus expressing cloned influenza virus gene products. These findings indicate that both integral membrane proteins and internal proteins that comprise virions can be processed by antigen-presenting cells for recognition by class I-restricted CTL. It also appears that not all hemagglutinin determinants recognized on virus-infected cells are presented by cells sensitized with heat-treated virus.

Animals↗
PubMed1988

Cryoelectron microscopy of vitrified Sendai virions.

Morphology of vitrified Sendai virions was studied by transmission type electron microscopy. Almost all the virions appeared to be completely spherical, although their diameters differed. A possibly continuously long nucleocapsid was seen running helically in an envelope. Spikes were seen on the virion surfaces. The results indicate pleomorphism of Sendai virions in size but not in shape.

Freezing↗