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Biomedical subjects

Y Kurono

Publications and source records attributed to Y Kurono.

At least 55 records · Page 3Linked to original sources
PubMed1991

Esterase-like activity of human serum albumin. VII. Reaction with p-nitrophenyl 4-guanidino-benzoate.

The reaction of p-nitrophenyl 4-guanidinobenzoate (NPGB) with human serum albumin (HSA) was examined kinetically at various pH's and 25 degrees C. The Michaelis constant (Ks in M) and the catalytic rate constant (k2 in s-1) were determined. The ratio of k2 to k0 (hydrolysis rate constant of NPGB in s-1) at pH 7.4 was 75.6, indicating the esterase-like activity of HSA. The effects of the reversible binding of site-specific drugs and the chemical modification by site-specific reagents on the HSA activity indicated that HSA has multiple reactive sites towards NPGB. Results of the reaction in the presence of excess NPGB over HSA also suggested the existence of multiple active sites. The pH-profile for k2 showed inflection points at about pH 6.0 and pH 10.0, suggesting the involvement of groups with pKa's of 6.0 and 10.0 in HSA.

Benzoates↗
PubMed1990

The role of bacterial adherence in otitis media with effusion.

Adherence of nontypable Haemophilus influenzae and Streptococcus pneumoniae to nasopharyngeal epithelial cells was investigated in vitro. Both strains had higher affinity to the epithelial cells of children than to those of adults. In children, the adherence was significantly greater in patients with otitis media with effusion than in normal subjects. Secretory IgA in nasopharyngeal secretions was found to have antibody activity against the bacteria. Adherence of both bacteria was significantly smaller in the group having secretory IgA antibody activity than in the group having no activity. These results suggest that bacterial adherence to the nasopharynx may play an important role in the pathogenesis of otitis media with effusion in children, and that secretory IgA in nasopharyngeal secretions may be related to the decrease of adherence.

Adult↗
PubMed1990

Type I allergic reactions of the middle ear and eustachian tube: an experimental study.

To clarify the role of type I allergic reactions in etiology and pathogenesis of otitis media with effusion and to determine whether or not the middle ear is an allergic "shock" organ, we made animal models of nasal allergy in guinea pigs by passive sensitization with serum of homologous animals containing specific IgE antibodies. We also examined the eustachian tube, tympanic cavity (histologically), and tubal function after the induction of type I allergic reactions of the nose. However, the involvement of histologic changes was limited only up to the area near the pharyngeal orifice. The tubal dysfunction evoked by nasal allergic reactions was transient, culminating in no middle ear effusion. Upon direct antigen-challenge into the tympanic cavity, allergic changes were observed in the mucosa lining the tympanic bulla, even though no microscopic effusion was present. Findings of the present study suggest that type I allergic reactions of the nose are not an etiologic factor for otitis media with effusion, although the middle ear is potentially an allergic shock organ.

Animals↗
PubMed1990

[The behavior of 1,4-benzodiazepine drugs in acidic media. XVI. Estimation of cis/trans isomer ratio of benzodiazepinooxazoles using nuclear magnetic resonance shift reagent].

The ratio of cis/trans isomers (referring to 11b-substituent and 2- or 3-substituent) of benzodiazepinooxazoles was estimated by using the lanthanide shift reagent (Eu(fod)3-d27) for nuclear magnetic resonance (NMR) spectroscopy. The amide carbonyl oxygen at 6-position is considered to coordinate with the reagent, because the largest downfield shifts were observed at the amide carbonyl carbon (C-6) in 13C-NMR and the amide hydrogen (H-7) in 1H-NMR. The ratios depend largely on the substituents at 11b-, 2-, and 3-positions. The cis isomer for compounds having 11b-hydrogen increases with an increase in the bulkiness of the substituents at 2-position. The cis isomer for compounds having 3-methyl group decreases with change from 11b-2'-chlorophenyl group (mexazolam) to 11b-hydrogen.

Benzodiazepines↗
PubMed1989

Secretory IgA and bacterial adherence to nasal mucosal cells.

The ability of Streptococcus pyogenes to adhere to nasal mucosal cells was investigated by an in vitro assay system in order to clarify the actual role of secretory IgA in mucosal immunity in the nose. The number of bacteria adhering to isolated mucosal cells was significantly larger in patients with chronic sinusitis than in normal control subjects. The ability of bacteria to adhere, however, was significantly lower in the group of subjects having specific secretory IgA antibody activity to the M protein than in those having no secretory IgA activity. Findings demonstrated that mucosal immunity preventing or blocking the adherence of bacteria is impaired in patients with chronic sinusitis.

Antigens, Bacterial↗
PubMed1989

[Clinical evaluation of a new hand-held impedance audiometer].

In order to evaluate the accuracy and clinical availability of MicroTymp (Welch Allyn) which was new, portable, cordless, and hand-held impedance audiometer, 64 normal subjects and 52 patients with otitis media with effusion were examined by use of MicroTymp and Amplaid 702 (Dana Japan). The types of tympanogram were agreed with each other in 87% of ears. Six cases of type C tympanograms in MicroTymp were shown to be type A by Amplaid 702, and the average of peak pressure of MicroTymp was more negative than Amplaid 702. The difference of peak pressure seemed to be influenced by the speed of ear canal pressure change, because the speed of MicroTymp was considerably higher than Amplaid 702; -200mmH2O/sec in MicroTymp, and -50mmH2O/sec in Amplaid 702. In the experimental study on 7 normal ears, negative shift of peak pressure was observed by increasing the rate of ear canal pressure change from -25mmH2O/sec to -50mmH2O/sec in Amplaid 702. These findings suggest that one should note in the judgment of type C tympanogram in MicroTymp having the peak pressure close to -100mmH2O.

Acoustic Impedance Tests↗
PubMed1988

Staphylococcus epidermidis and Staphylococcus aureus in otitis media with effusion.

Bacteriologic investigation of middle ear effusion (MEE), external ear canal, and the nasopharynx was carried out on 458 patients with otitis media with effusion. Staphylococcus epidermidis was the most common bacteria in MEE, even after excluding the contaminants from the external ear canal, which had the same value of minimal inhibitory concentration as the paired MEE. The bacterial agreement of S epidermidis between MEE and the nasopharynx was extremely rare in contrast with Haemophilus influenzae, Streptococcus pneumoniae, and Branhamella catarrhalis, although the organism was also frequently isolated from the nasopharynx. Staphylococcus aureus, having the same minimal inhibitory concentration as that in the nasopharynx, was more frequently found in MEE than S epidermidis. The results suggest that S epidermidis found in MEE is not a pathogen, but rather a contaminant in many instances. Staphylococcus aureus seems to be a causative agent in otitis media with effusion.

Adolescent↗
PubMed1988

Multiple foreign bodies (fish bones) in the esophagus and rectum.

Multiple foreign bodies (fish bones) in the esophagus and rectum, seen in a 64-year-old man, are reported. This patient suffered from severe pain on swallowing after he had eaten fried fish. Five days later, he was referred to us, and underwent removal of a piece of fish bone under direct metal esophagoscopy. After surgery, fever and leukocytosis still continued, even though pain on swallowing disappeared. Periesophageal abscess was suspected; but no leakage or abnormal shadow was found by esophagography. Since the patient complained of severe anal pain five days after the endoscopic procedure, a romanoscopy was performed: a fish bone in the rectum and periproctal abscess were detected. Removal of the foreign body and incision of the periproctal abscess caused fever and leukocytosis to subside. A review of the literature revealed only a very few cases of multiple foreign bodies in the esophagus and lower digestive tract.

Endoscopy↗
PubMed1988

Otitis media with effusion and the nasopharynx. A bacteriological and immunological study.

The adherence of Haemophilus influenzae to nasopharyngeal mucosal cells was investigated in vitro. Secretory IgA antibody activity and the content of fibronectin in nasopharyngeal secretion were determined by enzyme-linked immunosorbent assay. Adherence was greater in children than in adults; and was significantly greater in children with otitis media with effusion than in control children. Secretory IgA and fibronectin in nasopharyngeal secretion were considered to influence adherence of H. influenzae to nasopharyngeal mucosa.

Adolescent↗
PubMed1988

The role of nasal allergy in otitis media with effusion. A clinical study.

In order to clarify the role of Type I immunologic reactions in the etiology of otitis media with effusion (OME), kindergarten and elementary school children were given routine nasal allergy (NA) tests and otologic tests. Several children among them were evaluated for eustachian tube (ET) function before and after the intranasal histamine challenge, using the inflation-deflation test, and the nine-step inflation and deflation tympanometric test. The results clarified that NA-patients showed a high ratio (21%) of complication with OME, and that OME-patients showed a high ratio (50%) of complication with NA. It was also found that the incidence of tubal dysfunction was higher in OME-patients with NA than in OME-patients without NA. The man period of time between the removal and replacement of a tympanostomy tube was 11 months in OME-patients with NA who underwent hyposensitization; whereas the mean period of time was 2 months in OME-patients with NA who underwent no treatment for NA. The findings of the present study suggest that NA affects tubal function (even if the effect is temporary), and that NA may be a risk factor in OME-prone children.

Acoustic Impedance Tests↗