Search PubMed⌕ Search

Biomedical subjects

K Ichimura

Publications and source records attributed to K Ichimura.

At least 163 records · Page 9Linked to original sources
PubMed1989

Dissociation and auto-oxidation of hemerythrin induced by SH-modification: a kinetic study.

Hemerythrin from Siphonosoma cumanense has a trimeric structure consisting of identical subunits, which have no cooperativity nor Bohr effect on oxygen-binding. The trimer was dissociated into its monomers by the modification of the SH group of its cysteines with p-chloromercuriphenylsulfonic acid (PCMPS), which was monitored by stopped-flow of both spectrophotomeric and small angle X-ray scattering methods. The results showed that the process involved sequential modification of the SH groups, dissociation into monomers, and auto-oxidation of ferrous iron in the active center. The modification of the SH groups with PCMPS followed second-order kinetics with a rate constant of 1.8 M-1.s-1. The dissociation and auto-oxidation followed first-order kinetics with rate constants of 4 X 10(-3) s-1 and 5 X 10(-4) s-1, respectively. The obtained rate of auto-oxidation was much faster than that in the native state. These findings lead to the conclusion that the trimeric state of S. cumanense hemerythrin is necessary to prevent auto-oxidation.

Animals↗
PubMed1989

Negative cooperativity of chicken ovotransferrin on Al(III)-binding.

Chicken ovotransferrin, an iron binding protein, has two metal binding sites (amino (N) and carboxy (C) terminal sites). It binds Cu(II), Al(III), Co(II), and other metals, as well as Fe(III). In this study, the selectivity and cooperativity of the N and C sites on Al(III), Co(II), and Tb(III) binding were investigated. Metals were classified into two groups according to their site preference. Co(II) and Al(III) bound to the N site more preferably than to the C site, whereas Tb(III) bound to the C site more preferably. On Fe(III) binding, the binding constant of Fe(III) becomes larger when the other site is already occupied. Thus, positive cooperativity is seen. In the present study, the binding cooperativities of Co(II), Tb(III), and Al(III) as to the N and C sites were investigated. On Co(II) and Tb(III) binding, no cooperativity was observed, as in the case of Cu(II) [Yamamura, T. et al. (1985) in Proteins of Iron Storage and Transport (Spik, G., Montreuil, J., Crichton, R.R., & Mazurier, J., eds.) pp. 53-56, Elsevier Science Publ. B.V., Amsterdam]. In contrast, negative cooperativity was observed on Al(III) binding. Based on a model proposed by Yamamura et al. [Yamamura, T. et al. (1985) ibid.], the ratio of the binding constants, KC/KN, and the stacking coefficient, Kst, were estimated. KC/KN is 2.2 +/- 0.4 for the Tb(III) ion, 0.5 +/- 0.1 for the Co(II) ion, and 0.12 +/- 0.02 for the Al(III) ion. Kst (= 1 in a non-cooperative case) is 0.98 +/- 0.02 for the Tb(III) ion, 1.03 +/- 0.02 for the Co(II) ion, and 0.55 +/- 0.22 for the Al(III) ion.

Aluminum↗
PubMed1989

[Effects of periodontopathic bacterial components on phagocytic activity of rat peritoneal macrophages. Examination using ELISA].

This study examined the phagocytic activity of rat peritoneal resident macrophages to determine the movement of macrophages in local inflammation in periodontal disease. We studied phagocytic activity by enzymelinked immunosorbent assay (ELISA) and used the peroxidase-anti-peroxidase soluble complex (PAP; soluble immune complex) as a marker in. We also determined the basic conditions of this examination and studied the effects of bacterial components and the supernatants of sonicated periodontopathic bacterias. We obtained the number of applied macrophages, the concentration of PAP to use and the incubation time. The phagocytic activity of macrophages was enhanced significantly by the bacterial components lipopolysaccharide (LPS) and muramyldipeptide (MDP). Phagocytic activity was also enhanced by the addition of the supernatant of sonicated Bacteroides gingivalis at 40 micrograms/ml (concentration of protein) and significantly suppressed at 320 micrograms/ml. Moreover, activity was significantly enhanced by the supernatant of sonicated Capnocytophaga suputigena at 40 micrograms/ml and 160 micrograms/ml, and suppressed by the supernatant of Fusobacterium nucleatum at a low concentration of protein (5 micrograms/ml). These results suggested that LPS of gram-negative bacteria's endotoxicity and MDP on pivotal structure of peptidoglycans, which are bacterial cell surface components, exerted an effect on phagocytic activity. It was further indicated that the phagocytic activity of macrophages varied with the effects of each periodontopathic bacteria.

Animals↗
PubMed1989

[The role of high-resolution CT in evaluating disease of the posterior tympanum].

The posterior tympanum consists of several irregular eminences, ridges, and sinuses. These sinuses do not communicate with the mastoid air cell system, and cholesteatoma and/or granulation tissue prefer to fill them. This area cannot be visualized with ease by the usual surgical approach, and is thus quite important for surgeons. Recent developments in high-resolution computed tomography (HRCT) allow more than ever precise identification of subtle changes in the posterior tympanum. Axial HRCT sections provide essential information for the preoperative evaluation of the posterior tympanum. The performance of surgeons has been promoted both in evaluation and treatment planning of patient with suspected posterior tympanic lesions. HRCT findings were compared with the operative findings in 52 patients (54 ears) who had the operation for chronic otitis media. Important findings by HRCT diagnosis of posterior tympanum are as follows: (1) Bone destruction in the posterosuperior part of the tympanic anulus and in the lateral wall of the facial sinus are the important findings for the diagnosis of invasion of cholesteatoma in the posterior tympanum. (2) Similarly important finding is the bone destruction of the pyramidal eminence. This was found in 6 of 9 cases with cholesteatomas extending into the sinus tympani. (3) The soft tissue density in the posterior tympanum does not necessarily indicate pathological processes. Effusion in the posterior tympanum is imaged as soft tissue density, and can not be differentiated from cholesteatoma or granulation by present HRCT.

Adolescent↗
PubMed1989

[Superstructure of stapes: an analysis by high-resolution computed tomography].

High-resolution Computed Tomography (HRCT) of the temporal bone has now become a routine test for the diagnosis of various temporal bone lesions. Correct assessment of such minute structures as ossicles, especially stapes, is important in the pre-operative HRCT evaluation. On the other hand, analysis for the reliability of HRCT findings has not been done, including the superstructure of the stapes. A retrospectively study was done in order to assess the availability of HRCT findings in axial overlapping scans in 226 ears, with respect to the superstructures of stapes. The study was concerned with the analysis of HRCTs of 148 normal ears, 71 ears of chronic otitis media and 7 ears of ossicular abnormalities. HRCT findings were compared to those of surgeries in pathological cases. The present study revealed that the superstructures of stapes are noted in 70% when the stapes surrounded by air. The major limitations in the proper analysis of stapes by HRCT are partial volume averaging and effects of soft tissue silhouetting, this is especially so when the stapes is surrounded by soft tissue density.

Chronic Disease↗
PubMed1989

Auto-oxidation of Lingula unguis and Siphonosoma cumanense hemerythrins induced by some perturbants.

Auto-oxidation of human adult hemoglobin and Siphonosoma cumanense and Lingula unguis hemerythrins were investigated in the presence and absence of perturbants. In the presence of urea, there were no drastic increases in auto-oxidation rates for the three proteins. In contrast, thiocyanate and laurate enhanced the auto-oxidation rates remarkably. In the presence of thiol reagents such as PCMB and NEM, auto-oxidation rates were enhanced with dissociation into subunit, but not enhanced so much with SH-modification only. Thus oligomerization is probably necessary to protect auto-oxidation.

Animals↗
PubMed1988

Postjunctional alpha 2-adrenoceptors in blood vessels of human nasal mucosa.

Human nasal mucosa has various types of blood vessels and is a good tissue for demonstrating receptors for many vasoactive substances, including alpha-adrenoceptors. In contrast to the large contractile response induced by alpha 1-agonists, our studies have shown that alpha 2-agonists produce a small maximal contraction. This alpha 2-induced response was easily blocked by alpha 1-antagonists, indicating that it is evoked, at least partially, by the stimulation of alpha 1-adrenoceptors. Noradrenaline (NA)-induced contractions could not be abolished by either alpha 1- or alpha 2-antagonists alone, but were almost completely blocked by the combination of both antagonists. This suggests the presence of postjunctional alpha 2-adrenoceptors. The low-maximal responsiveness to alpha 2-agonists and calcium independency of NA-induced contractions were distinct from our former results obtained on canine nasal specimens.

Adrenergic alpha-Agonists↗
PubMed1987

Health concerns of parents of school-aged children in Japan.

"The study described in this paper was one of the first systematic attempts to identify the verbalized health concerns of parents of school-age children in Japan and provided some viable data for initiating the development of relevant health curriculum".

Adult↗
PubMed1987

Significance of tangential views in lumbar discography.

In 64 patients with 69 herniated lumbar discs, craniocaudal or caudocranial tangential views were made in addition to conventional posteroanterior (PA) and lateral views in lumbar discography. Tangential views more clearly demonstrated details of annular tears and herniated discs in comparison with conventional views. The advantages of tangential views are as follows: precise demonstration of position, width, and shape of the hernial opening (main annular tear); precise demonstration of position and shape of the herniated mass; and a topographic display of disc degeneration. Dermal radiation absorbed during tangential views is less than that of computerized tomographic (CT) scans of discography. In addition, tangential views can be readily made at any hospital. The disadvantages of tangential views are that the X-ray tube direction must be chosen for each individual depending on whether there is a cranially or caudally migrated disc herniation; there is a tendency toward decreased sharpness of the exposure, especially when there are advanced degenerative discs; and, absorbed doses of gonadal radiation are higher during caudocranial tangential views than during CT discography in women.

Adolescent↗
PubMed1986

Simultaneous quantitative measurement of fourteen adrenal steroids by capillary column gas chromatography-mass spectrometry, and its clinical application.

Until now, there has been little work covering all of the main native adrenal-cortical steroids in blood. We therefore established a method for the simultaneous quantitative measurement of 14 native adrenal-cortical steroids, which involves capillary column gas chromatography-mass spectrometry (GC--MS). Serum steroids were purified from serum with the Extrelut mini-column and then converted into stable derivatives for GC-MS by a combination of boronic cyclization and trimethylsilyl and methyloxime derivatization. The sensitivities (with a signal-to-noise ratio greater than or equal to 7) of our GC-MS method ranged from 0.1 to 1.0 ng/ml of serum, and the coefficients of variation of intra- and inter-assays were less than 19% for each steroid. Our newly devised method involving a capillary column GC-MS system has been proven to be a simple and suitable method for a diagnosis requiring simultaneous detection of many native adrenal steroids in clinical practice. The analysis time is only 4 h.

Adrenal Cortex Hormones↗
PubMed1985

[The establishment of the assay-system of blood adrenal steroids in the method of gaschromatograph/mass spectrometry (GC/MS)].

In this study, we established a method for the quantitative measurement of native adrenal steroids with GC-MS equipped with capillary column (cross-linked methyl silicone 25 m X 0.2 mm I.D., 0.11 m thin film). 1 ml of serum sample containing 5 alpha-cholestane as internal standard (IS) was elicited by organic solvent using extrelunt column. These samples were derived by n-butylboronic acid, o-methylhydroxylamine and trimethyl-silylating agents, then were finally applied to GC-MS. The intensities of molecular ions were used for the measurement of the serum concentration of steroids. The molecular ion peaks of steroids were obtained at m/z460 (17 alpha-hydroxyprogesterone; 17OHP), m/z548 (corticosterone; B), m/z470 (11-deoxycortisol; S), m/z417 (pregnenolone; PL), m/z372 (progesterone; PT), m/z558 (cortisol; F), m/z389 (dehydroepiandrosterone; DHEA), m/z371 (estrone; E1), m/z416 (estradiol; E2), m/z504 (estriol; E3), m/z389 (testosterone; T), m/z344 (androstenedione; A) and m/z372 (IS). The curve of calibration for each steroid showed good linearity. The sensitivities of the GC/MS method were less than 5pg/one shot of each sample. The coefficients of variations of accuracies and precisions in this GC/MS method were less than 15% of each steroid. The samples from normal subjects after metyrapone and ACTH loading tests, and the patients of congenital adrenal hyperplasia showed a good correlationship between the data of GC/MS and the data of RIA after sephadex LH-20 column-chromatography. These results implied the usefulness of our system in clinical application. Moreover, this assay takes only 3 hrs. Thus it saves much time in comparison with the time-consuming radioimmunoassay system.

Adrenal Cortex Hormones↗
PubMed1985

Lung cancer and chronic interstitial pneumonia associated with systemic sarcoidosis.

Lung cancer and chronic interstitial pneumonia associated with systemic sarcoidosis was detected in a 66-year-old woman at autopsy. Histologically, hyalinized sarcoid lesions were scattered in cervical lymph nodes, thoracic lymph nodes, abdominal lymph nodes, and spleen. Scattered non-caseating epithelioid cell granulomas with giant cells were observed in both lungs demoting cancer and chronic interstitial pneumonia. A tumor mass occupying right hilar portion was well-differentiated squamous cell carcinoma involving right upper lobe and right hilar lymph nodes. In the lower lobe of the left lung, a small nodule of poorly differentiated squamous cell carcinoma was detected. Alveolar septa, especially in both lower lobes of the lungs were thickened diffusely with fibrosis, edema, and inflammatory cell infiltration. Alveolar cavities contained hyaline membrane and large mononuclear cells. Atypical bronchiolar epithelial proliferation and squamous metaplasia associated with squamous cell carcinoma were detected. The clinical and pathological characteristics among eight reported cases of lung cancer associated with sarcoidosis and three reported cases of interstitial pneumonia associated with sarcoidosis were reviewed separately. There is no report describing both lung cancer and chronic interstitial pneumonia associated with sarcoidosis.

Aged↗