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Biomedical subjects

K Kitajima

Publications and source records attributed to K Kitajima.

At least 127 records · Page 7Linked to original sources
PubMed1996

Induction, localization, and purification of a novel sialidase, deaminoneuraminidase (KDNase), from Sphingobacterium multivorum.

Recently, we reported the discovery of a new type of sialidase, KDNase, which specifically hydrolyzes the ketosidic linkages of 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid (KDN), but not N-acylneuraminyl linkages. We now report that this enzyme, designated KDNase SM, is an inducible enzyme that is localized in the periplasm of Sphingobacterium multivorum. Growth of S. multivorum in the presence of KDN-containing oligosaccharide alditols, KDNalpha2-->3Galbeta1-->3GalNAc alpha1-->3[KDNalpha2--> (8KDN alpha2-->)n-->6]GalNAcol, as a sole carbon source induced KDNase SM activity 15 40-fold, compared with growth in the absence of inducer. KDN, Neu5Ac, or Neu5Ac oligomers were ineffective as inducers. The enzyme was released from the periplasm of induced cells by cold osmotic shock and purified 700-fold to homogeneity. The specific activity of the pure enzyme was 82,100 units/mg of protein. KDNase SM activity resided in a single polypeptide chain with an estimated molecular weight of approximately 47,500. Enzyme activity was maximal at near neutral pH. The availability of pure KDNase will now make it possible to study the structure and functional role of KDN-glycoconjugates and to determine the molecular mechanism whereby the enzyme can discriminate between KDN and N-acylneuraminic acid.

Chromatography, Ion Exchange↗
PubMed1996

Isolation and identification of novel sulfated and nonsulfated oligosialyl glycosphingolipids from sea urchin sperm.

Novel sulfated and nonsulfated oligosialylglycosphingolipids were isolated from sperm of the sea urchin, Hemicentrotus pulcherrimus, and their structures were established as follows: [formula: see text] This provides the first evidence for the natural occurrence of a tetrasialic acid structure in glycosphingolipids. The finding of sulfated oligosialyl chains is especially noteworthy in that the sulfate group exclusively resides on the C-8 of the nonreducing terminal residues of oligo/polysialyl chains and that sulfation appears to be a termination signal for elongation of oligosialyl chains. Sulfation at the nonreducing terminal Neu5Ac residues of oligosialyl chains was also found to facilitate the formation of an inter-residue lactone between the carboxyl group at the nonreducing terminal sulfated Neu5Ac and the hydroxyl group at C-9 of the penultimate Neu5Ac residue. The long chain base was 4-hydroxysphinganine (t18:0) and the major fatty acid species were identified as C20:1, C21:1, and C22:1.

Animals↗
PubMed1996

[Indicators of social functioning and social participation in mentally ill participants in a public health rehabilitation programme: a one year follow-up study].

In order to investigate social functioning, a self-administered questionnaire was distributed to 66 participants (30 men and 36 women) in a group rehabilitation programme for the mentally ill at public health centers, and followed for 1 year to investigate their employability as an indicator of social participation. The survey included 20 items related to 5 aspects of daily life: diurnal routine, basic personal management, social activities, personal relationships, and management of illness. The major findings were as follows: 1. The group who had become employed showed significantly higher positive responses to questions concerning self-management such as conversation with others, consultation with others and when condition worsened than the unemployed group. Also the employed showed a tendency for higher positive responses to such items as cooking, keeping appointments, taking medicine, taking an active role in managing medications. 2. According to discriminant analysis by Hayashi's quantification method II, factors distinguishing 17 participants who had become employed within the year and those who remained unemployed included the following: ability to converse with others, taking an active role in managing medications, and ability to cook, male gender, co-residence with family, and a period of 3 years or less since hospital discharge. These results suggest that a public health rehabilitation program aimed at improving interpersonal skills, self-management of illness and other skills of daily living may be useful in helping the mentally ill participate socially.

Adult↗
PubMed1996

Ex vivo surgery for renal artery aneurysms.

BACKGROUND: Renal artery aneurysms (RAAs), once considered rare, are being recognized with increasing frequency. The treatment of aneurysms of the first ramification of the main renal artery is still controversial. METHODS: From November 1984 to May 1992, we treated 8 patients with RAA at the first ramification. All the patients were treated with an ex vivo technique and autotransplantation. RESULTS: The results, evaluated with intravenous pyelogram and arteriography were satisfactory. No operative deaths and no complications were noted. CONCLUSION: We concluded that surgery with an ex vivo technique and autotransplantation is an excellent method of treating this type of lesion.

Adult↗
PubMed1996

Syndrome of resistance to thyroid hormone: insights into thyroid hormone action.

Thyroid hormones (T3, T4) exert multiple cellular effects through nuclear thyroid hormone receptors (TR alpha, TR beta). Thyroid hormone receptors are transcription factors that act by altering patterns of gene expression. Resistance to thyroid hormone (RTH) is a rare disorder caused by mutations in the TR beta gene. Biochemically, the syndrome is defined by elevated circulating levels of free thyroid hormones due to reduced target tissue responsiveness and normal, or elevated, levels of thyroid-stimulating hormone (TSH). This "inappropriate" TSH elevation contrasts with the situation in hyperthyroidism, where the pituitary secretion of TSH is suppressed. Patients with RTH usually present with goiter and an euthyroid or mildly hypothyroid metabolic state. Thus, pituitary resistance results in hypersecretion of TSH, which compensates, at least in part, for hormone resistance in peripheral tissues. Despite this compensation, clinical effects of RTH can include short stature, delayed bone maturation, hyperactivity, learning disabilities, and hearing defects, as well as variable features of hyper- and hypothyroidism. With the exception of a single sibship, which harbored a deletion of the entire coding sequence of the TR beta gene and a recessive pattern of inheritance, all other cases of RTH have been inherited in an autosomal dominant manner or have been de novo heterozygous mutations of the TR beta gene. The dominant pattern of inheritance is explained by the functional properties of the mutant receptors which act in a dominant negative manner to block the activity of normal TR alpha and TR beta receptors. Now that a large number of different RTH mutations have been identified, it is striking that the mutations are clustered within restricted domains in the carboxyterminal region of the receptor. Mutations in these regions have been shown to preserve critical receptor functions such as dimerization and DNA binding, while inactivating other activites such as T3 binding and transcriptional activation. The examination of patients with RTH and their mutated receptors has provided important insights into the mechanisms of thyroid hormone action, the structure-function relationship of the receptors, and the molecular mechanisms of dominant negative activity.

Amino Acid Sequence↗
PubMed1996

[Long-term results of Feldmann's osteoplastic approach for chronic middle ear disease].

Between 1978 and 1981, Feldmann's osteopathic approach was often used to manage chronic middle ear disease. In this procedure, the superior and posterior segment of the ear canal wall was cut after complete mastoidectomy, removed temporarily and re-positioned in the previous position after handling the diseased focus in the tympanic isthmus area. Forty-one cases (24 cases of non-cholesteatomatous chronic otitis media and 17 cases of cholesteatoma) were followed and long-term results of this procedure were studied with regard to re-operative findings following this procedure. Among the 41 patients, 13 (31.7%) required revision surgery because of cholesteatoma formation, infection etc. Seven of these 13 patients (53.8%) required revision surgery because of cholesteatoma formation after this procedure. None of these 7 cases appeared to involve residual cholesteatoma. The most important problem is that 3 of the 7 patients showing cholesteatoma formation had non-cholesteatomatous chronic otitis media before this procedure. In other words, the Feldmann's osteoplastic approach may iatrogenically induce cholesteatoma formation in non-cholesteatomatous chronic otitis media. The re-operative findings indicated that the re-positioned canal wall in this procedure may have small bony defects or bony erosion, inducing pocket formation through these defects to create a new cholesteatoma. Although recent literature concerning tympanoplasty recommends posterior canal wall reconstruction using cartilage, bone, ceramic material or bone-pate rather than the canal wall down method, careful follow-up should be continued with regard to pocket formation and/or cholesteatoma formation.

Cholesteatoma, Middle Ear↗
PubMed1995

Characterization of the antigenic specificity of four different anti-(alpha 2-->8-linked polysialic acid) antibodies using lipid-conjugated oligo/polysialic acids.

A rapid, sensitive, and facile method for screening and characterizing anti-polysialic acid (polySia) antibodies using lipid-conjugated oligo/polysialic acids (oligo/polySia) was developed, which is based on an enzyme-linked immunosorbent assay. Homooligo/polymers of alpha 2-->8-linked N-acetylneuraminic acid (Neu5Ac), N-glycoly-neuraminic acid, and 2-keto-3-deoxy-D-galacto-nononic acid (KDN) were conjugated with phosphatidylethanolamine dipalmitoyl (PE) by reductive amination to prepare neo-oligo/polysialoglycolipids (oligo/polySia-PE). Using this method, the anti-polySia equine antibody, H.46, bound to (-->8Neu5Ac alpha 2-->)n-PE, where n = 9 or more residues, a result in confirmation of previous binding studies using radiolabeled oligo/polyNeu5Ac. The antigenic specificity and sensitivity of two monoclonal anti-poly/oligoNeu5Ac antibodies (mAb.12E3 and mAb.5A5) and one anti-oligoKDN antibody (mAb.kdn8kdn), were also determined. mAb.12E3 could detect as little as 25 pg/well of oligo/polyNeu5Ac-PE, while 0.4 ng/well of oligo/polyNeu5Ac-PE to be detected. mAb.kdn8kdn detected as little as 12 ng/well of oligoKDN-PE. Using a series of oligo/polySia-PE with defined degrees of polymerization (DP), the minimum chain length for immunoreactivity of the anti-polySia antibodies was determined to be: DP 5 for mAb.12E3; DP 3 for mAb.5A5; DP 2 for mAb.kdn8kdn; and DP 8 for H.46. Thus, mAb.12E3 and mAb.5A5 recognize shorter oligomers of Neu5Ac than H.46, a finding that is of practical value for identifying shorter oligoSia chains in glycoconjugates. Because mAb.12E3 and mAb.5A5 also recognize extended polySia chains, these antibodies cannot be used, however, to differentiate between short and long chains of polySia when both are expressed on the same molecule.

Animals↗
PubMed1995

Carbohydrate-binding property of peptide: N-glycanase from mouse fibroblast L-929 cells as evaluated by inhibition and binding experiments using various oligosaccharides.

Carbohydrate binding to peptide: N-glycanase from mouse fibroblast L-929 cells (L-929 PNGase) and inhibition by oligosaccharides of its catalytic activity were studied. L-929 PNGase was found to bind strongly with oligosaccharides having triomannosido-N,N'-diacetyl-chitobiosyl (Man3GlcNAc2) structure (Kd = approximately 10 microM). This binding was inhibited by mannotriose (Man3; Man alpha 1-->3[Man alpha 1-->6]Man) but not by N,N'-diacetylchitobiose (GlcNAc2; GlcNAc beta 1-->4GlcNAc). Scatchard analysis indicated that there exist two binding sites for Man3 on a homodimeric form of a 105-kDa subunit. Oligosaccharides having Man3GlcNAc2 structure were also shown to be strong inhibitors for the PNGase-catalyzed reaction (Ki = approximately 10 microM). The minimum structural requirements for inhibition of the PNGase activity were Man3 and GlcNAc2. Enzyme kinetic studies showed that the mechanism of inhibition by the oligosaccharides and Man3 fits well with a model wherein two inhibitor binding sites reside on L-929 PNGase. The conformity of Kd with IC50 values may be taken as an evidence for inhibition of the catalytic activity by the oligosaccharides and Man3 through the occupation of the binding sites with these molecules. On the other hand, inhibition by GlcNAc2 followed the simple competitive mode. Since the minimum substrate for the L-929 PNGase was shown to be Man beta 1-->4GlcNAc beta 1-->4GlcNAc beta 1-->peptide, GlcNAc2 may be directly accessible to the catalytic site in competition with substrate. Interestingly, alkylation of -SH group in L-929 PNGase caused complete loss of the catalytic activity, but the carbohydrate binding activity was completely retained, indicating that the catalytic site(s) is discriminated from the carbohydrate-binding sites in the active site of this enzyme. The carbohydrate-binding property seems to be unique to soluble PNGases from mammals and may be associated not only with regulation of the enzyme activity, but also with receptor and carrier functions for glycoconjugates in certain intracellular processes.

Amidohydrolases↗
PubMed1995

Identification and distribution of peptide:N-glycanase (PNGase) in mouse organs.

A wide occurrence of peptide:N-glycanase (PNGase) in mouse organs was demonstrated. PNGase activities were determined using 14C-labeled fetuin glycopeptide I as a substrate by a newly improved enzyme assay based on the paper chromatographic and paper electrophoretic analyses. PNGase activities were detected in both soluble and membranous (or particulate) fractions, although the levels of the activities were different from organ to organ. Soluble PNGases were partially purified from brain, liver, kidney, and spleen by TSK butyl-Toyopearl 650 M hydrophobicity chromatography and characterized for enzymatic properties. The soluble enzymes were found to share the following properties: (a) high hydrophobicity; (b) sensitivity to metal cations such as Zn2+, Cu2+, and Fe3+; and (c) requirement of sulfhydryl group(s) for enzyme activity. Notably, soluble PNGases were unable to degrade glycoasparagine substrates and the optimal pH was near 7.0, suggesting that they were not lysosomal enzymes, but perhaps being involved in basic biological processes in certain intracellular nonlysosomal events. All of these enzymatic properties found for mouse organ-derived PNGases were the same as those recently found for L-929 PNGase that was highly purified as a soluble enzyme from mouse fibroblast L-929 cells (Suzuki, T., Seko, A., Kitajima, K., Inoue, Y., and Inoue, S. (1994) J. Biol. Chem. 269, 17611-17618.

Amidohydrolases↗
PubMed1995

Fos induction in the medullary dorsal horn and C1 segment of the spinal cord by acute inflammation in aged rats.

In order to elucidate the effect of aging on nociceptive neurons in the central nervous system, c-fos was used as a marker of excitability of neurons in the medullary dorsal horn (MDH) and the first spinal segment (C1) following noxious stimulation of the lateral face of young and aged rats. The distribution of c-fos-positive cells was dense in the superficial laminae and sparse in the deep laminae of the MDH and C1 in both young and aged animals following subcutaneous injection of formalin into the lateral face, whereas few c-fos-positive cells were labeled after saline injection. The distribution of c-fos-positive cells in the superficial laminae of the aged rats was found to be denser and more rostro-caudally expanded compared to that in the young rats. C-fos-positive cells were distributed more rostro-caudally in aged than in young rats. There was no difference between young and aged rats in the distribution of c-fos-positive cells in the deep laminae. Substance P (SP), 5-HT and calcitonin gene-related peptide-like immunoreactive (CGRP-LI) fibers and varicosities showed similar distribution density in the MDH and C1. Furthermore, many 5-HT-LI aberrant fibers and varicosities were observed in the MDH and C1 of the aged rats. The SP-LI and CGRP-LI cells in the trigeminal ganglion of aged rats were larger than those of young rats. These findings suggest that a deficit of the descending 5-HT inhibitory system produces the increment of c-fos-positive cells in the MDH and C1 of aged rats, resulting in the recruitment of a larger number of neurons in the superficial laminae of the MDH and C1 for conveying nociceptive sensory information to the central nervous system.

Age Factors↗
PubMed1995

Proton NMR study of the trimannosyl unit in a pentaantennary N-linked decasaccharide structure. Complete assignment of the proton resonances and conformational characterization.

The chemical shifts of all the ring protons of the three Man residues in a pentaantennary glycan chain have been unambiguously assigned by two-dimensional proton nuclear magnetic resonance (1H-NMR) spectroscopic methods. The study, using chemical shift and J values on the conformation of the trimannosyl unit, revealed that the rotamer about the C5-C6 bond of the alpha 1-->6 linkage in the sequence of Man alpha 1-->6Man beta 1--> is predominantly confined to a gauche-gauche rotamer (omega = 180 degrees, omega = O6-C6-C5-H5) and not to a gauche-trans rotamer (omega = -60 degrees). We do not know of any previous demonstration that the dihedral angle omega (O6-C6-C5-H5) in Man alpha 1-->6Man beta 1--> is preferentially 180 degrees in complex-type N-linked glycans having no bisecting GlcNAc residue.

Amino Acid Sequence↗
PubMed1995

REM sleep without atonia at early stage of sporadic olivopontocerebellar atrophy.

In order to investigate whether REM sleep without atonia (RWA) is detected even at early stage of sporadic olivopontocerebellar atrophy (OPCA), all-night polysomnography with video monitoring was performed on 5 patients presenting with no nocturnal behavioral complaints. RWA associated with sleep talk and/or minor movements in the head, neck, face and extremities was documented in all cases. Preserved proper NREM/REM cycle and relatively normal sleep architecture suggest the abnormality is confined to REM sleep. Dysfunction of the mechanisms underlying muscle atonia in REM sleep, especially functional or anatomical interruption of ponto-medullary pathways mediating REM sleep atonia, seems to cause RWA in these patients. RWA may be a clinically important finding as a sign of brainstem dysfunction at early stage of neurodegenerative diseases.

Aged↗
PubMed1995

The effects of intraoral pressure change on F0 regulation--preliminary study for the evaluation of vocal fold stiffness.

This study was intended to evaluate the stiffness of the vocal folds noninvasively. As a first step, the relationship between vocal fundamental frequency (F0) and intraoral pressure (P0) was investigated. F0 was recorded during production of forced P0 changes in three men and four women while they uttered sustained vowels. The pressure changes were applied by closing a valve mounted on a mouthpiece. Changes in F0 as a function of changes in P0 (dF0/dP0) were then measured. The values of dF0/dP0 varied with F0 in a manner inherent to each subject. The relationship between dF0/dP0 and F0 was found to have a potential benefit for the evaluation of stiffness at a specific length of vocal fold.

Adult↗
PubMed1995

Dominant negative and DNA-binding properties of mutant thyroid hormone receptors that are defective in homodimerization but not heterodimerization.

Thyroid hormone receptors (TRs) bind to thyroid hormone response elements (TREs) as monomers, homodimers, and heterodimers. Mutations that cause resistance to thyroid hormone (RTH) have proven useful for identifying important functional domains in the receptor. Previous studies have shown that RTH mutants must retain the ability to form heterodimers with RXR to exert dominant negative inhibition of wild-type receptor function. In this report, we examined in detail the dimerization properties, function, and dominant negative activity of RTH mutations at R316H and R338W--two mutations that have a propensity to cause the pituitary form of RTH. These mutants show selective loss of homodimerization, with preservation of heterodimerization with RXR alpha. The selective loss of homodimerization was independent of the orientation of the half sites in the TRE. The R316H mutant was transcriptionally inactive in transient expression assays, consistent with its markedly reduced T3 binding. In contrast, R338W was activated at nanomolar concentrations of T3, precluding quantitative analyses of its dominant negative properties. In cotransfection assays with wild-type TR beta, the R316H mutant functioned in a dominant negative manner to block positively (TRE-pal; DR4) and negatively (TSH alpha) regulated reporter genes, although its inhibitory potential was reduced compared with other RTH mutants. Introduction of the R316H mutation into a receptor containing a potent RTH mutant (G345R) reduced its dominant negative activity to the level of the R316H mutant alone. These results suggest that mutations that alter homodimerization have reduced dominant negative activity for some target genes, a feature that may account, in part, for phenotypic variability in RTH.

Base Sequence↗
PubMed1995

Expression of new KDN-gangliosides in rainbow trout testis during spermatogenesis and their structural identification.

The developmental expression of 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid-containing glycosphingolipids (KDN-gangliosides) in rainbow trout testis during spermatogenesis was studied using a monoclonal antibody, mAb.kdn3G, which recognizes the KDN alpha 2-->3Gal beta 1-->epitope. A major KDN-ganglioside found in mature sperm, (KDN)GM3, KDN alpha 2-->3Gal beta 1-->4Glc beta 1-->Cer (where Cer is ceramide), was expressed in testis throughout all stages of its maturation. On the contrary, four new KDN-gangliosides which were reactive with mAb.kdn3G were not detected in mature sperm, although they were identified in immature testis and expressed during spermatogenesis. The structures of these KDN-gangliosides were established by chemical, enzymatic and immunochemical methods as: (i) (KDN)GD1a, KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer; (ii) (KDN, Neu5Ac)GD1a, KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(Neu5Ac alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer and Neu5Ac alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer; (iii) (KDN) GD1 alpha, KDN alpha 2-->3Gal beta 1-->3(KDN alpha 2-->6)GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->Cer; and (iv) (KDN,Neu5Ac)GD1 alpha, KDN alpha 2-->3Gal beta 1-->3(Neu5Ac alpha 2-->6)GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->Cer. (KDN)GD1a and (KDN,Neu5Ac)GD1a first appeared at an early stage of spermatogenesis, but (KDN)GD1 alpha and (KDN,Neu5Ac)GD1 alpha were not expressed until 2 months prior to spermiation. While (KDN)GM3 was previously shown to contain only 4-sphingenine (d18:1) acylated with a C16:0 fatty acid, the new KDN-gangliosides discovered in this study were composed of 4-hydroxysphinganine (t18:0) or 4-sphingenine (d18:1), and were acylated with a C24:1 or C16:0 fatty acid. A possible function of these KDN-gangliosides is suggested.

Acylation↗
PubMed1995

A precise structural analysis of a fertilization-associated carbohydrate-rich glycopeptide isolated from the fertilized eggs of euryhaline killi fish (Fundulus heteroclitus). Novel penta-antennary N-glycan chains with a bisecting N-acetylglucosaminyl residue.

A novel carbohydrate-rich sialoglycopeptide of apparent molecular mass approximately 6 kDa was isolated from the fertilized eggs of Fundulus heteroclitus (euryhaline killi fish). This glycopeptide is a member of the L-hyosophorin family, characterized by its high content of carbohydrate (80-90% by weight) and formed by depolymerization of the precursor glycopoly-protein (H-hyosophorin) upon fertilization. The structures of the N-glycan chains were unambiguously established by a combination of compositional analysis, methylation analysis, selective chemical degradation (periodate oxidation-Smith degradation and hydrazinolysis-nitrous acid deamination), enzymatic (peptide:N-glycosidase F, several beta-galactosidases, beta-hexosaminidase and alpha-galactosidase) digestions and instrumental analyses (1H-NMR and fast atom bombardment mass spectrometry) to have the novel and unique carbohydrate sequences, Gal alpha 1-->3(Gal beta 1-->4)Gal beta 1-->4GlcNAc beta 1--> and Gal alpha 1-->3(+/- GalNAc beta 1-->4GlcNAc beta 1-->3Gal beta 1-->4)Gal beta 1-->4GlcNAc beta 1-->. This study represents the first detailed investigation of the nature of bulky complex asparagine-linked penta-antennary glycans with a bisecting GlcNAc residue in glycoproteins. Expression of such bulky multiantennary glycan units on proteins may be essential during early embryogenesis.

Acetylglucosamine↗