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Biomedical subjects

K Oikawa

Publications and source records attributed to K Oikawa.

At least 109 records · Page 6Linked to original sources
PubMed1987

Increase in the glucosylated form of erythrocyte Cu-Zn-superoxide dismutase in diabetes and close association of the nonenzymatic glucosylation with the enzyme activity.

Human erythrocytes contain glucosylated and nonglucosylated Cu-Zn-superoxide dismutases which can be separated by boronate affinity chromatography. The percentage of the glucosylated form is significantly increased in the erythrocytes of patients with diabetes as compared to normal erythrocytes. The nonglucosylated form of Cu-Zn-superoxide dismutase, which was washed through the boronate column, was glucosylated in vitro upon exposure to radioactive or non-radioactive D-glucose. Incorporation of D-glucose into the protein was observed, and with the increase in glucosylation, the enzymatic activity decreased, indicating that the glucosylation of the enzyme led to a low active form. This is the first demonstration that superoxide dismutase is glucosylated in erythrocytes and that the glucosylation leads to the inactivation of the enzyme.

Blood Glucose↗
PubMed1987

Histopathological investigation of DMF-induced hepatotoxicity.

N,N-Dimethylformamide (DMF) has been implicated in the production of hepatotoxicity in male and female F344 rats. Repeated administration of dosages of 0.75 and 1.0 ml/kg DMF for up to 12 weeks produced massive liver necrosis associated with decreased body weight gain. Macroscopically, areas of necrotic change were well pronounced in every hepatic lobe, being yellowish-red in coloration, irregular in shape, and varying in size, but were most striking immediately adjacent to the porta hepatis. Among the lobes, those which were relatively small were most markedly affected, and occasionally an entire lobe was involved. Light and electron microscopic studies revealed the hepatic architecture to be occupied by massive fibrosis. There were, however, sharp lines of demarcation between surviving normal and necrotic areas. Hemosiderosis involving macrophages was accompanied by proliferative bile ductules and a number of multinucleated giant cells. The distribution and quality of the hepatic lesions produced by DMF were discussed.

Administration, Oral↗
PubMed1987

Genetic control of the immune responsiveness to Streptococcus mutans by the major histocompatibility complex of the rat (RT1).

The lymph node cells from 11 strains of rats, differing in the genotype of the major histocompatibility complex of the rat (RT1), were examined on the basis of their proliferative response to the cell wall antigen of Streptococcus mutans. The 11 rat strains fell into three groups: high, intermediate, and low responders. To demonstrate the influence of the major histocompatibility complex on immune responsiveness to S. mutans, further experiments were performed using the RT1-congenic rat strains WKAH.1L(LEW), WKAH. 1AV1(ACI), and WKAH.1J(LEJ), which differ only in the genotype of the RT1 region. Although the background genes of each strain were of WKAH origin, WKAH.1L(LEW) and WKAH.1AV1(ACI) rats showed a low response whereas WKAH.1J(LEJ) rats showed a moderate response to the S. mutans cell wall antigen. The results indicate that the immune response is controlled by the class II gene(s) in RT1. Furthermore, the RT1.D locus products were shown to play an important role in the restriction molecule, since a monoclonal antibody, HOK7, directed to the RT1.Dk locus products reduced the proliferative response of lymph node cells.

Animals↗
PubMed1986

[Statistics on the diagnosis and treatment of infertile patients--psychologic examination and analysis of the questionnaire].

Authors present the statistics of the diagnosis and treatment of infertile patients who visited the outpatient clinic of the Department of Obstetrics and Gynecology, School of Medicine, University of Occupational and Environmental Health, Japan throughout 1985. The number of primary infertility (78) was greater than that of secondary infertility (63). The average age and the duration of infertility were 30.5 y. old/3.86 y. (primary) and 31.6 y. old/3.59 y. (secondary), respectively. The most frequent cause of infertility was ovarian-endocrine factor both in primary and secondary infertilities. The second cause was the male factor in primary infertility in spite of the idiopathic factor in secondary infertility. Tubal disorder as a cause was relatively few in both infertilities. So-called open laparoscopy was performed on 11 patients, with little hope of cure. In eight of these patients, disorders of tubal patency and endometriosis, which were not found by hysterosalpingography and hydrotubation before laparoscopy, were discovered for the first time. In twenty pregnancies at the day of statistics, the number of secondary infertility (13) was greater than that of primary infertility (7). All pregnant cases were under 35 years of age and under 5-year of infertility duration at the initial visit to our outpatient clinic. The number 1 cause of infertility was ovarian-endocrine factor. In eight pregnant cases, hysterosalpingography was performed in the same or one cycle before the pregnant cycle. According to the summation of the questionnaire of 65 infertile patients, most of infertile patients were affirmative to in-vitro-fertilization and embryo transfer. Depressive and neurotic tendencies were not remarkable at that time by Self-Rating-Depression Scale (SDS) and Cornell Medical Index (CMI) in 42 infertile patients.

Adult↗
PubMed1986

Purification of Cu-Zn-superoxide dismutase from human erythrocytes by immunoaffinity chromatography. Evidence for the presence of isoelectric heterogeneity.

Cu-Zn-superoxide dismutase (SOD) was prepared in highly purified form from human erythrocytes by immunoaffinity chromatography using anti-human Cu-Zn-SOD goat IgG. The purified SOD had a high specific activity and gave a single band on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. On isoelectric focusing and immunoblotting several bands with enzyme activity and antigenicity were discerned.

Chromatography, Affinity↗
PubMed1986

1H NMR spectroscopic studies of calcium-binding proteins. 2. Histidine microenvironments in alpha- and beta-parvalbumins as determined by protonation and laser photochemically induced dynamic nuclear polarization effects.

The microenvironments of the histidines in three isoforms of Ca(II)-bound parvalbumin (carp, pI = 4.25; pike, pI = 5.00; rat, pI = 5.50) have been examined with 1H NMR techniques to probe their protonation characteristics and photochemically induced dynamic nuclear polarizability (photo-CIDNP). The histidine at position 26 (or 25), present in all three of these proteins, shows absolutely no photo-CIDNP enhancement of its C2H or C5H resonances. Nor does this nonpolarizable histidine possess a normal pKa: values range only from 4.20 for carp to 4.32 for pike to 4.44 for rat. The C2H and C5H resonances of the histidine in this carp isoform split into doublets as the pH is lowered. The magnitude of this splitting depends on the magnetic field strength, temperature, and pH; however, the line intensities within each doublet are temperature-independent. Although the crystal structure of carp parvalbumin indicates that His-26 is exposed to solvent [Kretsinger, R. H., & Nockolds, C. E. (1973) J. Biol. Chem. 248, 3313-3326], we conclude that in solution this residue, in its unprotonated state, is part of the hydrophobic core of the protein. In contrast, His-48 in rat parvalbumin and His-106 in pike III parvalbumin show dramatic photo-CIDNP enhancements of their C2H, C5H, and beta-CH2 1H NMR resonances. Combined with its nearly normal pKa, 6.14, and exchange-broadened C2H resonance, the photo-CIDNP enhancement results for His-48 indicate that its microenvironment differs little from random-coil exposure, consistent with its presumed position on the solvent surface of helix C.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

1H NMR spectroscopic studies of calcium-binding proteins. 3. Solution conformations of rat apo-alpha-parvalbumin and metal-bound rat alpha-parvalbumin.

Lacking the extraordinary thermal stability of its metal-bound forms, apo-alpha-parvalbumin from rat muscle assumes two distinct conformations in aqueous solution. At 25 degrees C, its highly structured form predominates (Keq = 5.7; delta G degree = -4.3 kJ X mol-1); as deduced from both 1H NMR and circular dichroism (CD) spectroscopy, this conformation is exceedingly similar to those of its Mg(II)-, Ca(II)-, and Lu(III)-bound forms. The temperature dependences of several well-resolved aromatic and upfield-shifted methyl 1H NMR resonances and several CD bands indicate that the native, highly helical structure of rat apo-alpha-parvalbumin is unfolded by a concerted mechanism, showing no indication of partially structured intermediates. The melting temperature, TM, of rat apo-alpha-parvalbumin is 35 +/- 0.5 degrees C as calculated by both spectroscopic techniques. By 45 degrees C, rat apo-alpha-parvalbumin unfolds entirely, losing the tertiary structure that characterizes its folded form: not only are the ring-current-shifted aromatic and methyl 1H NMR resonances leveled, but the 262- and 269-nm CD bands are also severely reduced. As judged by the decrease in the negative ellipticity of the 222-nm CD band, this less-structured form of rat apo-alpha-parvalbumin shows an approximate 50% loss in apparent alpha-helical content compared to its folded state. Several changes in the 1H NMR spectrum of rat apo-alpha-parvalbumin were exceptionally informative probes of the specific conformational changes that accompany metal ion binding and metal ion exchange. In particular, the line intensities of the ortho proton resonance of Phe-47, the unassigned downfield-shifted alpha-CH resonances from the beta-sheet contacts between the metal-binding loops, the C2H resonance of His-48, and the epsilon-CH3 resonance of an unassigned Met residue were monitored as a function of added metal to determine the stability constants of several metal ion-parvalbumin complexes. We conclude that Mg(II) binds to the CD and EF sites independently, its affinity for the EF site being almost twice that for the CD site. Mg(II)----Ca(II) exchange showed that the CD-site Mg(II) is displaced first, in contrast to Lu(III)'s preferential displacement of the EF-site Ca(II) as determined from the Ca(II)----Lu(III) exchange experiments.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Comparative calcium binding and conformational studies of turkey and rabbit skeletal troponin C.

Troponin C from turkey skeletal muscle has been compared with its chicken counterpart in terms of amino acid composition and fragmentation patterns and with rabbit TN-C by Ca2+ binding and conformational response to Ca2+ as monitored by CD and fluorescence. Cyanogen bromide and tryptic digestion mixtures of chicken and turkey TN-C have been separated by reversed-phase HPLC. The similarity of the elution profiles, along with the almost identical amino acid compositional data, suggest that the sequences are essentially equivalent. Both turkey and rabbit TN-C bound 2 mol Ca2+/mol protein at pH 5.3, while at pH 6.8, this figure was raised to 4 mol/mol protein. Circular dichroism and fluorescence measurements indicated that the conformations of the two proteins responded in a very similar manner to the presence of Ca2+.

Amino Acids↗
PubMed1986

Possible induction of disseminated intravascular coagulation in the mouse by group B streptococcal clumping factor.

A hydrochloric acid extract, the clumping factor fraction, obtained from a clumping factor-positive strain of group B streptococci, was capable of killing mice by administration after injection of heat-killed cells of group B streptococci or Escherichia coli intravenously. In mice killed between 24 and 48 h later, fibrin thrombi were observed in the renal glomeruli, as well as in the heart, lung, liver, and pancreas. These findings suggest the possible induction of disseminated intravascular coagulation by these organisms in the mouse.

Animals↗
PubMed1986

Effects of aging on the formation of ester forms of riboflavin in the rat lens.

We studied the effects of aging on the formation of ester forms of riboflavin in the lens of rats. The formation was highest in newborn and 2-week-old rats; a sharp decrease was noted at one month, thereafter it continued to decrease gradually reaching a plateau at 3 months. In general, esterification of riboflavin was higher in female than male rats. We found that a decrease in the esterification of riboflavin with increasing age is a characteristic change in the rat lens. This finding may help to clarify the pathogenesis of senescent change in the lens.

Aging↗
PubMed1985

Physicochemical properties of a novel Mr-21 000 Ca2+-binding protein of bovine brain.

The physicochemical properties of a novel Mr-21 000 Ca2+-binding protein isolated from bovine brain were investigated. The protein exhibited a partial specific volume of 0.724 ml/g, a degree of hydration of 0.47 g of water/g of protein and a mean residue weight of 119. Sedimentation equilibrium analysis revealed Mr = 22 600 in the absence of Ca2+; Ca2+ binding appeared to induce dimerization of the molecule. Size-exclusion chromatography indicated a compacting of the molecule on binding of Ca2+: the Stokes radius decreased from 2.75 nm in the absence of Ca2+ to 2.56 nm in its presence. Far-u.v.c.d. spectroscopy showed the apoprotein to be composed of 44% alpha-helix, 18% beta-pleated sheet and 38% random coil. Addition of either KCl (0.1 M) plus Mg2+ (1 mM), or Ca2+ (2 mM), changed the conformation to 49% alpha-helix, 18% beta-pleated sheet and 33% random coil. Near-u.v.c.d. and u.v. difference spectroscopy both indicated perturbations in the environments of all three types of aromatic amino acids on binding of Ca2+. Ca2+ binding also resulted in a 30% enhancement in the tryptophan fluorescence emission intensity. Ca2+ titration of the far-u.v.c.d. and fluorescence enhancement provided KD values of 9.91 microM and 4.68 microM respectively. Finally, the protein was shown to bind Zn2+ with KD = 1.44 microM (no Mg2+) and 1.82 microM (+ Mg2+). These observations strongly support the possibility that this novel Ca2+-binding protein resembles calmodulin and related Ca2+-binding proteins and undergoes a conformational change on binding of Ca2+ which reflects a physiological role in Ca2+-mediated regulation of brain function.

Animals↗
PubMed1985

Conformation and stability of the anion transport protein of human erythrocyte membranes.

The conformation and stability of purified preparations of band 3, the anion transport protein of human erythrocyte membranes, and its constituent proteolytic subfragments have been studied by circular dichroism. Band 3, purified in the presence of the nonionic detergent n-dodecyl octaethylene glycol monoether (C12E8), had an alpha-helical content of 46%. Denaturation of purified band 3 with guanidine hydrochloride occurred in two phases, one reflecting much more resistance to denaturation than the other. Band 3 can be separated into two domains by limited in situ proteolytic cleavage. The carboxyl-terminal membrane-associated domain (Mr 55 000) purified in C12E8 contained 58% alpha-helix and was very resistant to denaturation by guanidine hydrochloride. The purified amino-terminal, cytoplasmic domain (Mr 41 000) contained 27% alpha-helix and was completely converted to a random-coil conformation by 3 M guanidine hydrochloride. The two phases of denaturation observed for intact band 3 corresponded to the two domains of the protein. Irreversible heat denaturation of purified band 3 occurred with half-maximal change in theta 222.5 at 48 degrees C. Covalent attachment of the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonate to band 3 had little effect on the circular dichroism spectra of band 3 or the membrane-associated domain but resulted in stabilization of band 3 to heat denaturation (half-maximal change in theta 222.5 = 61 degrees C). Circular dichroism studies of membranes that had been digested extensively with proteolytic enzymes and stripped of all extrinsic fragments revealed that the portions of red cell membrane proteins that are embedded in the lipid bilayer contain a very high (86-94%) content of alpha-helix.

Amino Acids↗
PubMed1985

Protein phosphorylation of beta-glucuronidase in human lung cancer--identification of serine- and threonine-phosphates.

Slices of human lung cancer tissue were incubated with [32P]-orthophosphoric acid, and the radiolabeled beta-glucuronidase was isolated by a procedure including immunoaffinity chromatography on anti-human liver beta-glucuronidase IgG Sepharose. Following removal of endo-beta-N-acetyl-glucosaminidase H-releasable carbohydrate portions of the enzyme, the protein moiety was acid-hydrolyzed. Two-dimensional separation of the hydrolysate identified phosphoserine and phosphothreonine. This is the first demonstration of protein phosphorylation in lysosomal beta-glucuronidase.

Adenocarcinoma↗