Biomedical subjects

Y Kurono

Publications and source records attributed to Y Kurono.

At least 37 records · Page 2Linked to original sources

PubMed1998

Enhancement of nasal clearance of nontypeable Haemophilus influenzae by oral immunization with outer membrane proteins.

BALB/c mice were orally immunized with liposomes containing outer membrane proteins (OMPs) isolated from nontypeable Haemophilus influenzae (NTHi) and GM-53 as an adjuvant daily for 14 days. Anti-OMP IgA antibody titers in nasal wash, saliva, and fecal extract were significantly increased after the immunization. Although anti-OMP IgM and IgG antibodies were detected in serum, serum IgA antibodies specific to OMPs were not found. Enzyme-linked immunospot assay showed an increased number of OMP-specific IgA-secreting cells in nasal passages, intestinal lamina propria lymphocytes, and the spleen. Following oral immunization, a suspension of live NTHi was injected into the nose; nasal washes were collected 12 h after the inoculation. The number of NTHi in nasal washes was significantly reduced in mice immunized with liposomes containing OMPs and GM-53 compared to that in mice immunized with liposomes containing GM-53 alone. There was a significant negative correlation between the number of NTHi and anti-OMP IgA antibody titers in nasal washes. These findings suggest that antigen-specific IgA responses in the nose can be induced by oral immunization with OMPs and might be associated with the ability to clear NTHi from the nose.

Adjuvants, Immunologic↗

PubMed1998

Changes in immunostaining of inner ears after antigen challenge into the scala tympani.

To study the mechanisms of immune responses and immune injuries in inner ears, labyrinthitis was induced by inoculation of keyhole limpet hemocyanin (KLH) into the scala tympani of systemically sensitized guinea pigs. Inner ears were then immunostained for KLH, immunoglobulin G (IgG), albumin, connexin26 (Cx26), and sodium-potassium adenosine triphosphate (Na,K-ATPase). Inflammatory cells containing KLH were observed in the scala tympani and in the collecting venule of the spiral modiolar vein (SMV). Spiral ligament, spiral limbus, and blood vessels including the SMV were diffusely positive for IgG and albumin. Immunoreactivity for Cx26 and Na,K-ATPase was decreased compared with the normal ears in the fibrocytes of the spiral ligament. These results suggest that inflammatory cells and blood constituents could extravasate into the cochlea from blood vessels and that fibrocyte damage in the spiral ligament could cause cochlear dysfunction.

Adjuvants, Immunologic↗

PubMed1998

Immune responses of adenoidal lymphocytes specific to Haemophilus influenzae in the nasopharynx.

OBJECTIVES: Investigate immune responses of adenoidal lymphocytes against outer-membrane protein P6 purified from nontypeable Haemophilus influenzae (HI). Clarify the role of adenoids in regulating the colonization of HI in the nasopharynx. STUDY DESIGN: Microbiological and immunological examinations of adenoids obtained from 21 children, 15 boys and five girls, from 1 to 13 years of age (median, 5 y), suffering from adenoidal hypertrophy complicated by otitis media with effusion (OME). METHODS: The incidence of HI in adenoids was compared with the number of P6-specific immunoglobulin (Ig) A-secreting cells in adenoids, determined by enzyme-linked immunoassay. RESULTS: Quantitative culture assay showed significant correlation between the numbers of HI in adenoids and those in nasopharyngeal secretions (NS). In children aged 5 years and younger, the numbers of P6-specific IgA-secreting cells in adenoids were significantly correlated with IgA antibody titers in NS (r = 0.68, P < .05). The numbers of P6-specific IgG- and IgA-secreting cells were lower in children aged 6 years and older than in children aged 5 years and younger. Furthermore, the number of P6-specific IgA-secreting cells was significantly increased in HI-negative subjects when compared with HI-positive subjects (P < .05). CONCLUSIONS: Adenoids play an important role as an effector site of the mucosal immune system in the upper respiratory tract. IgA immune responses in adenoids are responsible for the clearance of HI from the nasopharynx.

Adenoids↗

PubMed1998

Role of superoxide dismutase in otitis media with effusion.

The concentration of superoxide dismutase (SOD) in middle ear effusion (MEE) was measured by the electron spin resonance trapping method in order to clarify the role of SOD in otitis media with effusion (OME) in children. The SOD levels in mucoid MEEs were significantly higher than those in serous and purulent MEEs. There was no significant difference in the levels of SOD between neutrophil-dominant MEEs and mononuclear cell-dominant MEEs, and the levels were negatively correlated with the number of neutrophils in the MEEs. Moreover, the levels were significantly increased in patients having recurrence of MEE within 3 months compared with patients without recurrence of MEE. Although it is known that SOD plays an important role in protecting the host from oxygen radicals, the findings in this study suggest that SOD might be related to the chronicity of OME.

Adolescent↗

PubMed1998

[The role of IL-1 beta in murine model of otitis media with effusion].

Recent studies have demonstrated the presence of inflammatory cytokines such as IL-1 beta, TNF-alpha, IL-6, and IL-8 in the middle ear effusion (MEE) of patients with otitis media with effusion (OME). IL-1 beta is known to be produced from macrophages and monocytes in an early stage of inflammation by stimulation with microorganisms and endotoxins. Also, these studies have shown that endotoxins frequently are found in MEE and can induce OME in experimental animal model. These findings suggest that endotoxins in MEE cause a chain reaction of cytokines through IL-1 beta. However, the precise role of IL-1 beta in the pathogenesis of OME has not yet been clarified. In the present study, a murine model of OME was developed by intra-tympanic injection with endotoxin or recombinant mouse IL-1 beta (rIL-1 beta) and the effects of IL-1 beta on the production of MEE were investigated. OME was induced in specific pathogen-free male BALB/c mice by intra-tympanic inoculation with endotoxin purified from nontypeable Haemophilus influenzae or with rIL-1 beta. The presence of MEE in the subjects was observed through the ear drum under a microscope and samples of MEE were collected by aspiration and washing with phosphate-buffered saline. The concentrations of IL-1 beta in each sample of MEE were determined by ELISA and the histological changes were compared. The mice inoculated with endotoxin showed signs of the production of MEE and it was noted that the levels of IL-1 beta in MEE were significantly increased on day 3. Intra-tympanic inoculation with rIL-1 beta also produced MEE and these cytological findings of MEE as well as the histological findings of middle ear mucosa were similar to those found in the endotoxin-induced OME. Further, the influence of anti-IL-1 receptor antibodies on the production of OME was examined 3 days after intra-tympanic injection with anti-IL-1 receptor antibodies together with endotoxin or rIL-1 beta. The incidence of OME was lower in mice injected with anti-IL-1 receptor antibodies than that in mice injected with endotoxin or rIL-1 beta only. These findings suggest that IL-1 beta may play an important role in the pathogenesis of OME.

Animals↗

PubMed1997

The role of immune complex in otitis media with effusion.

Fifteen chinchillas were inoculated with immune complexes of Streptococcus pneumoniae into the tympanic cavity, and with formalin-killed bacteria into the opposite side. Middle ear effusion (MEE) were found in 14 ears having inoculation with immune complexes and in only four ears having inoculation with formalin-killed S. pneumoniae. In another experiment, 20 chinchillas received intra-tympanic inoculation with live S. pneumoniae after systemic immunization with formalin-killed S. pneumoniae of the same strain. As a control, 12 chinchillas were inoculated with live bacteria of the same strain into the tympanic cavity without pre-immunization. MEE was observed in nine of pre-immunized animals and persistent MEE lasting for more than 3 weeks was observed in seven of the animals. In control, persistent MEE was not observed. Though six animals developed otitis media with effusion (OME). The results suggest that the formation of immune complexes in the tympanic cavity plays an important role in the occurrence of persistent MEE after pneumococcal otitis media.

Animals↗

PubMed1997

Immune responses against Streptococcus pyogenes in human palatine tonsils.

We investigated cellular immunity against Streptococcus pyogenes in human tonsils by measuring antigen-specific immunoglobulin-secreting cells and the production of cytokines from CD4+ T cells in response to M proteins. The incidence of S pyogenes in tonsils was significantly higher in patients with recurrent tonsillitis (RT) than in patients with tonsillar hypertrophy (TH). M protein-specific immunoglobulin A (IgA) and immunoglobulin G spot-forming cells were increased in patients with RT compared with patients with TH. In RT the number of M protein-specific IgA spot-forming cells was significantly greater in the S pyogenes-negative subjects than in the S pyogenes-positive subjects. Proliferation of CD4+ T cells and production of interferon-gamma (IFN-gamma) and interleukins -2, -4, -5, and -6 (IL-2, IL-4, IL-5, and IL-6) from those T cells were observed in response to M protein. The concentrations of IFN-gamma and IL-4 were higher in RT than in TH. These findings suggest that S pyogenes is associated with the pathogenesis of RT and that immune responses against M protein may play an important role in preventing the colonization of this bacteria in tonsils.

Adolescent↗

PubMed1996

Effects of oral and systemic immunization on nasopharyngeal clearance of nontypeable Haemophilus influenzae in BALB/c mice.

BALB/c mice were immunized orally or subcutaneously with formalin-killed nontypeable Haemophilus influenzae (NTHi). Salivary immunoglobulin A (IgA) antibody titers against NTHi were significantly increased by oral immunization, but not by subcutaneous immunization. Both immunization procedures remarkably increased the levels of serum antibody activities of both IgA and immunoglobulin G. Live NTHi were then inoculated into the naso-pharynx, and the clearance of the pathogen from the nasopharynx was observed. Significantly fewer bacteria were present in the nasopharynx of the orally immunized mice than in the control mice. However, there was no significant difference between the subcutaneously immunized mice and the control mice. The results indicate that oral immunization can enhance the ability of mice to clear NTHi from the nasopharynx.

Administration, Oral↗

PubMed1996

Detection of Haemophilus influenzae in adenoids and nasopharyngeal secretions by polymerase chain reaction.

Haemophilus influenzae in the nasopharynx is thought to be related to the pathogenesis of otitis media with effusion (OME). However, the positive rate measured by the conventional culture method is not high enough for bacterial infection to be considered the chief pathogenic factor. Polymerase chain reaction (PRC) and the conventional culture method were applied to detect H. influenzae in the adenoids and nasopharyngeal secretions of 17 children with OME (2 to 7 years of age). The percentage of P6-positive adenoid samples was 82.4% while 70.6% were culture positive. In nasopharyngeal secretions, 88.2% were P6-positive and 64.7% were culture positive. All samples in which H. influenzae was cultured were positive with PCR. The positive rate was significantly greater with PCR than with the culture method, and it showed a significant concordance between adenoids and nasopharyngeal secretions (p = 0.0027). These findings suggest that the presence of H. influenzae in the nasopharynx is more common in children with OME than previously reported, and that H. influenzae in adenoids might play an important role in OME.

Adenoids↗

PubMed1996

The role of adenoids in nasopharyngeal colonization with nontypeable Haemophilus influenzae.

Nasopharyngeal colonization with nontypeable Haemophilus influenzae (NTHi) and immune responses in the adenoid were studied in 18 patients with otitis media with effusion (OME) who underwent adenoidectomy. NTHi in excised adenoid tissue and in nasopharyngeal secretions was examined by quantitative culture assay. NTHi was detected in 13 adenoid samples and 12 nasopharyngeal secretions. In 11 cases, NTHi was cultured from both samples of nasopharyngeal secretion and adenoids, and the concentration of NTRi in nasopharyngeal secretions was significantly correlated with that in adenoids. A significant negative correlation was observed between anti-NTHi IgA antibody titers and the number of NTHi in nasopharyngeal secretions. The number of NTRi in nasopharyngeal secretions and adenoids was decreased in the cases having a large number of NTHi-specific IgA and IgG antibody-producing cells in their adenoids. The results suggest that mucosal immunity in the nasopharynx is responsible for reducing the colonization of NTHi, and that the adenoid plays an important role in regulating the immune responses.

Adenoids↗

PubMed1995

High incidence of Haemophilus influenzae in nasopharyngeal secretions and middle ear effusions as detected by PCR.

PCR was used to detect Haemophilus influenzae in samples of nasopharyngeal secretion and middle ear effusion (MEE). Nasopharyngeal secretions were collected from 102 patients with otitis media with effusion and from 111 healthy subjects. Eighty samples of MEE were collected from patients with otitis media with effusion. A pair of primers was designed to amplify a DNA segment of the gene encoding P6 outer membrane protein of H. influenzae. The amplified PCR product was detected with an internal probe that hybridized specifically to the P6 DNA of H. influenzae. Samples of MEE and nasopharyngeal secretion were also examined by a conventional culture method. The incidence of P6 gene DNA in nasopharyngeal secretions detected by PCR was about two times higher than that of H. influenzae detected by the conventional culture. Culture-positive samples were all positive in the PCR test. In MEEs, the rate of detection of the P6 gene DNA target was about five times higher than that of H. influenzae detected by the culture method. All patients who had P6 gene DNA in MEEs were found to have the DNA in nasopharyngeal secretions. These findings suggest that the presence of H. influenzae in MEEs and in nasopharyngeal secretions is more common than previously reported.

Bacteriological Techniques↗

PubMed1995

Effect of oxatomide on otitis media with effusion--an experimental study.

The therapeutic effect of oxatomide on experimental otitis media with effusion (OME) induced by secondary immune response was investigated in chinchillas. Oxatomide was administered daily in three different doses (5, 10, 30 mg/kg b.w.t.) for a period of 2 weeks, starting 2 days after the instillation of keyhole limpet hemocyanin (KLH) into the tympanic cavity. The severity of OME was assessed by observing the eardrum under a surgical microscope, by tympanography, and by histological findings. The concentrations of leukotriene C4 and LTD4 in middle ear effusion (MEE) were also measured, 7 days after the KLH instillation. It was found that oral administration of oxatomide in dosages of 10 and 30 mg/kg alleviated the experimental OME. The mean LTD4 concentration measured in MEE from chinchillas given 30 mg oxatomide was significantly lower than that measured in the control group. The radioactivity of 14C-labelled oxatomide in MEE and the autoradiographic findings revealed that orally administered oxatomide was rapidly absorbed from the digestive tract and transported to the middle ear via blood circulation. The findings suggest that the effect of oxatomide can be anticipated in patients with OME.

Acoustic Impedance Tests↗

PubMed1995

Immunology of the tympanic membrane.

Under normal conditions, tympanic membranes lack immunocompetent cells, except mast cells and Langerhans cells in the pars flaccida, and the annular and manubrial regions of the pars tensa. Lymphocytes migrate to these regions after the induction of immune-mediated otitis media, although the other regions of the pars tensa do not show the presence of these cells. Langerhans cells appear throughout the entire tympanic membrane, in case of otitis media. The unique features of the immunological aspect of the tympanic membrane are discussed.

Animals↗

PubMed1993

[Interaction of camptothecin derivatives with human plasma proteins in vitro].

The interactions of camptothecin (CPT) and its derivatives (CPT-11 and SN-38) with human plasma proteins (serum albumin (HSA) and alpha 1-acid glycoprotein (alpha 1-AGP)) were studied mainly by means of ultraviolet and fluorescence spectroscopy. The binding constants of lactone ring-opened forms (A form) of CPT and CPT-11 with HSA were larger than those of the intact lactone forms (L form). In the case of SN-38, there was no difference in the constants between A form and L form. The binding constant of CPT (A form) with HSA was larger than those of CPT-11 and SN-38. The presence of cisplatin, which is presumed to be coadministered with CPT derivatives, did not affect the interaction of CPT derivatives with HSA. Only L form of CPT-11 among the CPT derivatives examined interacted with alpha 1-AGP, followed by quenching the fluorescence of alpha 1-AGP.

Binding Sites↗

PubMed1992

Inhibition of nasopharyngeal colonization of Hemophilus influenzae by oral immunization.

Nontypeable Hemophilus influenzae organisms were inoculated into the nasopharynx of BALB/c mice immunized by oral administration of formalin-killed bacteria. Salivary antibodies and the colonization of H influenzae in the nasopharynx were investigated in order to clarify the effect of oral immunization. Salivary immunoglobulin A antibody titers against H influenzae were significantly increased by oral immunization, but salivary immunoglobulin G antibody titers were not. The bacteria inoculated into the nasopharynx were more rapidly eliminated in immunized mice than in control mice. The results suggest that oral immunization might be useful in preventing otitis media with effusion by inhibiting the colonization of the nasopharynx by pathogenic bacteria.

Administration, Oral↗

PubMed1992

Esterase-like activity of human serum albumin. VIII. Reaction with amino acid p-nitrophenyl esters.

The reactions of human serum albumin (HSA) with optically active amino acid p-nitrophenyl esters (substrate, S) were examined kinetically at 25 degrees C. The rate data were analyzed in terms of a mechanism involving 1:1 complexing (S.HSA) between S and HSA. The dissociation constant (Ks in M) and the catalytic rate constant (k2 in s-1) of S.HSA were determined. Among ten substrates examined, the reactions with N-carbobenzoxy-D(L)-alanine p-nitrophenyl esters (N-CBZ-D(L)-AlaNP) were most accelerated by HSA. Results of the reaction in the presence of excess N-CBZ-D(L)-AlaNP over HSA indicated the existence of one strong reactive site on HSA. The effects of the reversible binding of the site-specific drug and the chemical modification by site-specific reagents on the HSA activity showed that the reactive site towards N-CBZ-D(L)-AlaNP is the R site located near tyrosine-411 residue of HSA.

Amino Acids↗

PubMed1991

Characterization of benzodiazepinooxazoles: crystal and molecular structure of trans and cis isomers of oxazolam.

The stereochemistry of the trans and cis isomers of 2(S)- and 2(R)-oxazolam is described. A total of four molecular structures of the 11b(R) and 11b(S) diastereomers of 2(S)- and 2(R)-oxazolam have been revealed by X-ray diffraction techniques. 2(S)-Oxazolam crystallizes in space group P2(1)/c, with cell dimensions a = 16.180(2) A, b = 8.791(2) A, c = 13.574(2) A, and beta = 102.07(1) degrees. The molecule in an asymmetric unit exhibited disorder at the 2-carbon (C2) atom, and the structures for trans and cis isomers have been resolved crystallographically. 2(S)-Oxazolam forms polymeric chains with intermediation of ethanol through hydrogen bonding. 2(R)-Oxazolam crystallizes in space group P1, with cell dimensions a = 7.754(1) A, b = 8.654(1) A, c = 15.795(2) A, alpha = 104.09(1) degrees, beta = 91.19(1) degrees, and gamma = 114.00(1) degrees. A similar disorder at the C2 position has been elucidated by a mixture of trans- and cis-2(R)-oxazolams. The two 2(R)-oxazolam molecules form a dimer with a hydrogen bond net. The structural details, focusing on the conformation and molecular complex formation of both oxazolams, have been discussed in connection with the oxazolidine ring stability and the crystal polymorph.

Anti-Anxiety Agents↗

PubMed1991

Inhibition of bacterial adherence by nasopharyngeal secretions.

The role of secretory immunoglobulin (Ig) A in nasopharyngeal secretions in the adherence of Streptococcus pneumoniae and Hemophilus influenzae to nasopharyngeal epithelial cells was investigated in vitro. The adherence was remarkably reduced by treating bacteria with nasopharyngeal secretions, and the antiadhesive activity was significantly greater in nasopharyngeal secretions having secretory IgA antibody activity against bacteria than in those having no activity. Noticeable changes were not observed in the antiadhesive activity caused by absorption of IgG from nasopharyngeal secretions. Results suggest that secretory IgA in nasopharyngeal secretions is related to bacterial adherence and adds to the prevention of nasopharyngeal infections.

Antibodies, Bacterial↗