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Biomedical subjects

M Hayakawa

Publications and source records attributed to M Hayakawa.

At least 73 records · Page 4Linked to original sources
PubMed2001

Does cyclooxygenase-2 inhibitor prevent renal tissue damage in unilateral ureteral obstruction?

PURPOSE: We determined whether the cyclooxygenase-2 inhibitor etodolac affects renal tubular damage and interstitial fibrosis in unilateral ureteral obstruction. MATERIALS AND METHODS: Etodolac (10 mg./kg.) was administered to rats 1 day before unilateral ureteral obstruction and every day thereafter. Kidneys were harvested at day 14 after unilateral ureteral obstruction. Tissue transforming growth factor-beta and prostaglandin E2 were measured by bioassay using mink lung epithelial cells and enzyme linked immunosorbent-sandwich assay. Renal tubular proliferation and apoptosis were detected by immunostaining with proliferating cellular nuclear antigen and by terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling, respectively. Cyclooxygenase-2 expression was detected by immunohistochemistry. Fibrosis was assessed by measuring collagen deposition in trichrome stained slides. RESULTS: Bioassay showed that in the control group obstructed kidneys contained significantly higher mean transforming growth factor-beta1 than unobstructed kidneys (79.1 +/- 8.3 versus 33.6 +/- 4.2 ng./gm. tissue) and etodolac significantly decrease the mean value in obstructed kidneys (46.2 +/- 10.0 ng./gm. tissue). Assay demonstrated that obstructed control kidneys had significantly more mean tubular apoptosis than their unobstructed counterparts (26.6 +/- 5.4 versus 2.2 +/- 1.4 nuclei per high power field) and etodolac significantly decreased mean renal tubular apoptosis in the obstructed kidneys (16.2 +/- 1.9 nuclei per high power field). In addition, immunostaining with proliferating cellular nuclear antigen showed that obstructed kidneys in the control group had significantly more mean renal tubular proliferation than unobstructed kidneys (9.8 +/- 3.4 versus 3.9 +/- 0.1 per high power field) and etodolac significantly increased mean proliferating renal tubule in the obstructed kidneys (24.9 +/- 4.3 per high power field). Control obstructed kidneys had significantly more fibrosis and prostaglandin E2 production, which were also significantly blunted by etodolac. CONCLUSIONS: The cyclooxygenase-2 inhibitor etodolac significantly reduces tissue transforming growth factor-beta, resulting in decreased tubular damage and interstitial fibrosis. This finding suggests that etodolac is a promising agent for preventing renal tissue damage in unilateral ureteral obstruction.

Animals↗
PubMed2001

[A clinical study of resected bronchopulmonary carcinoids].

19 surgically treated cases with bronchopulmonary carcinoid in our hospital were studied clinically, and we discussed the criteria of limited operation for typical carcinoid. 11 cases had typical carcinoid and 8 had atypical. All patients of typical type were alive with no recurrence. No lymph node metastasis was revealed in all cases of typical type. On the contrary, in cases of atypical type, 1 had n 2 disease and 1 had distant metastasis. The five survival rates of patients with typical carcinoid was 100%, and significantly better than that of patients with atypical, 27%. Therefore, patients with typical carcinoid can be cured by limited operation, but radical operation should be indicated for atypical carcinoid.

Adult↗
PubMed2000

Genetic linkage of Bietti crystallin corneoretinal dystrophy to chromosome 4q35.

Bietti crystalline corneoretinal dystrophy (BCD) is an autosomal recessive retinal degeneration characterized by multiple glistening intraretinal dots scattered over the fundus, degeneration of the retina, and sclerosis of the choroidal vessels, ultimately resulting in progressive night blindness and constriction of the visual field. Although BCD has been associated with abnormalities in fatty-acid metabolism and absence of fatty-acid binding by two cytosolic proteins, the genetic basis of BCD is unknown. We report linkage of the BCD locus to D4S426 (maximum LOD score [Z(max)] 4.81; recombination fraction [straight theta] 0), D4S2688 (Zmax=3.97; straight theta=0), and D4S2299 (Zmax=5.31; straight theta=0), on chromosome 4q35-4qtel. Multipoint analysis confirmed linkage to the region telomeric of D4S1652 with a Z(max) of 5.3 located 4 cM telomeric of marker D4S2930.

China↗
PubMed2000

Differential regulation of exonic regulatory elements for muscle-specific alternative splicing during myogenesis and cardiogenesis.

Muscle-specific isoform of the mitochondrial ATP synthase gamma subunit (F(1)gamma) was generated by alternative splicing, and exon 9 of the gene was found to be lacking particularly in skeletal muscle and heart tissue. Recently, we reported that alternative splicing of exon 9 was induced by low serum or acidic media in mouse myoblasts, and that this splicing required de novo protein synthesis of a negative regulatory factor (Ichida, M., Endo, H., Ikeda, U., Matsuda, C., Ueno, E., Shimada, K., and Kagawa, Y. (1998) J. Biol. Chem. 273, 8492-8501; Hayakawa, M., Endo, H., Hamamoto, T., and Kagawa, Y. (1998) Biochem. Biophys. Res. Commun. 251, 603-608). In the present report, we identified a cis-acting element on the muscle-specific alternatively spliced exon of F(1)gamma gene by an in vivo splicing system using cultured cells and transgenic mice. We constructed a F(1)gamma wild-type minigene, containing the full-length gene from exon 8 to exon 10, and two mutants; one mutant involved a pyrimidine-rich substitution on exon 9, whereas the other was a purine-rich substitution, abbreviated as F(1)gamma Pu-del and F(1)gamma Pu-rich mutants, respectively. Based on an in vivo splicing assay using low serum- or acid-stimulated splicing induction system in mouse myoblasts, Pu-del mutation inhibited exon inclusion, indicating that a Pu-del mutation would disrupt an exonic splicing enhancer. On the other hand, the Pu-rich mutation blocked muscle-specific exon exclusion following both inductions. Next, we produced transgenic mice bearing both mutant minigenes and analyzed their splicing patterns in tissues. Based on an analysis of F(1)gamma Pu-del minigene transgenic mice, the purine nucleotide of this element was shown to be necessary for exon inclusion in non-muscle tissue. In contrast, analysis of F(1)gamma Pu-rich minigene mice revealed that the F(1)gamma Pu-rich mutant exon had been excluded from heart and skeletal muscle of these transgenic mice, despite the fact mutation of the exon inhibited muscle-specific exon exclusion in myotubes of early embryonic stage. These results suggested that the splicing regulatory mechanism underlying F(1)gamma pre-mRNA differed between myotubes and myofibers during myogenesis and cardiogenesis.

ATP Synthetase Complexes↗
PubMed2000

Abnormal cerebral neuronal migration in a rat model of intrauterine growth retardation induced by synthetic thromboxane A(2).

Many reports have associated intrauterine growth retardation (IUGR) with adverse neurological outcome, but the underlying pathology is imperfectly understood. We have developed a new rat model of IUGR using maternal administration of synthetic thromboxane A(2) (STA(2)). In the present study, the effect of this insult on neuronal migration in the rat cerebral cortex was examined. Bromodeoxyuridine (BrdU), a time-specific cell marker was administered intraperitoneally to the mothers on embryonic day (E) 19. At postnatal day (P) 3, P4, P5, and P6, pups were terminally anesthetized and brains were removed. BrdU-labeled cells were detected immunohistochemically and counted in cerebrum, which was divided into the cortical plate (CP), the intermediate zone, and the subventricular/ventricular zone (SVZ+VZ). Numbers of labeled cells in the three areas over time were compared between IUGR and control animals. Numbers of labeled cells in SVZ+VZ were significantly greater in IUGR than in controls at P3, 5, and 6 (P<0.05). In contrast, labeled cells in the CP were significantly less abundant in IUGR animals than in controls at P3, 4, and 6 (P<0.05). We concluded that neuronal migration was delayed in IUGR rats.

Animals↗
PubMed2000

Application of a method incorporating differential centrifugation for selective isolation of motile actinomycetes in soil and plant litter.

The present paper describes a simple enrichment technique which enables rapid and selective isolation of diverse zoosporic actinomycete genera directly from soil and plant litter. This technique, designated the rehydration and centrifugation (RC) method, consists of immersing the air-dried source material in 10 mM phosphate buffer containing 10% soil extract, letting the preparation stand at 30 degrees C for 90 min, followed by centrifugation of the fluid at 1,500 x g for 20 min. Portions of the supernatant containing actinomycete zoospores are plated on the humic acid-vitamin agar which is supplemented with nalidixic acid and trimethoprim as the selective inhibitors for Gram-negative bacteria and bacilli. The phosphate buffer-soil extract solution significantly promoted liberation of motile zoospores from the source material. The centrifugation stage greatly eliminated streptomycetes and other non-motile actinomycetes from the liquid phase, thereby facilitating selective growth of rare, motile actinomycetes on the isolation plates subsequent to inoculation. Ten different soil and leaf-litter samples, taken from fields, forests, and stream banks, were examined. The RC method consistently achieved preferential isolation of motile actinomycetes in all samples, which accounted for 37-86% of the total microbial population recovered. The most frequently isolated motile actinomycetes were Actinoplanes and Dactylosporangium. Strains of Actinokineospora, Catenuloplanes and Kineosporia were also recovered, depending on the nature of the samples examined. Other motile actinomycetes that were occasionally isolated in small numbers included Actinosynnema, Geodermatophilus and Sporichthya.

Actinomycetales↗
PubMed2000

Psittacosis with increased gammadelta T cells in bronchoalveolar lavage fluid.

Experience with two cases of psittacosis is described here in which the number of gammadelta T cell receptor-positive T lymphocytes (gammadelta T cell) in the bronchoalveolar lavage fluid was markedly increased (25.1 and 66.9%) and CD8+ T cells were also increased with reversal of the CD4/CD8 ratio. These values improved to the normal range along with recovery of their radiographical findings. The present findings suggest that gammadelta T cells may play an important role in protection from lung injury caused by Chlamydia psittaci infection.

Adult↗
PubMed2000

Differences in the effects of 20 K- and 22 K-hGH on water retention in rats.

Antidiuretic actions induced by two growth hormone (GH) isoforms (20 K- and 22 K-hGH; 0.2 and 2.0 mg/kg) were evaluated in rats, as fluid retention may cause oedema, one of the adverse effects of GH. Both GH isoforms (2.0 mg/kg) suppressed urine excretion in hypophysectomized rats (P< 0.01), but only the 22 K-hGH isoform (2.0 mg/kg) suppressed urine excretion in intact rats (P< 0.01). In addition, prolactin (PRL) suppressed urine excretion in intact rats (P< 0.05). In conclusion, 20 K-hGH has less potency in causing urine retention than 22 K-hGH and since 20 K-hGH is missing 15 amino acids found in 22 K-hGH, these amino acids may be important for the antidiuretic action of GH. Since prolactin suppressed urine excretion, a part of the antidiuretic action of GH may be related to PRL-R activation.

Animals↗
PubMed2000

Reversible dimerization of 20 kilodalton human growth hormone (hGH).

A noncovalent dimer of the 22 kilodalton human growth hormone (22 K-hGH) is known to have diminished somatogenic activity compared with monomeric 22 K-hGH. In the present study, we examined the biological activity and physicochemical behaviour of a noncovalent dimer of the 20 kilodalton human growth hormone (20 K-hGH), an isoform of 22 K-hGH. Analysis of the equilibrium between monomeric and associated forms revealed that the associated 20 K-hGH was present in the dimeric form in aqueous solution. The kinetics of dimerization in rat plasma followed the theory of dissociation-association equilibrium, and more than 99% of 20 K-hGH molecules existed as a monomer in the equilibrium state at the physiological hGH concentration. Analysis of the pharmacokinetics showed that the ratio of the administrated dimer in rat circulation decreased from 43% to less than 4% in 2 h. A preparation of noncovalent dimeric 20 K-hGH had essentially the same degree of biological potency as that of a monomer in both in vitro and in vivo bioassays. In conclusion, dimerization of 20 K-hGH is reversible both in vitro and in vivo and a noncovalent dimer can function as a pharmaceutically active component of a 20 K-hGH preparation, in contrast to a 22 K-hGH preparation.

Animals↗
PubMed2000

Mechanism and prevention of enlargement or new development of aneurysm following treatment by clipping or coiling.

The mechanisms of cerebral aneurysm recurrence and enlargement were investigated in 11 patients: two with dissecting aneurysms, six with fully grown aneurysms after neck clipping, one with enlarged aneurysm after dome clipping, and two with enlarged aneurysm due to recanalization after GDC coil embolization. We concluded that it is fundamentally important to ensure complete attachment of the internal elastic lamina around the aneurysm neck by precise neck clipping and effective embolization, with accurate positioning of remaining internal elastic lamina.

Endothelium, Vascular↗
PubMed2000

Ascorbic acid improves postischemic vasodilatation impaired by infusion of soybean oil into canine iliac artery.

This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.

Animals↗
PubMed2000

Production, characterization, and application of monoclonal antibodies which distinguish four glucosyltransferases from Streptococcus sobrinus.

A 1,3-alpha-glucan synthase (GTF-I), a highly branched 1, 6-alpha-glucan synthase (GTF-U) and a 1,6-alpha-glucan synthase (GTF-T) were purified to near homogeneity from the culture fluid of Streptococcus sobrinus strain B13N (serotype d) and characterized. In addition, a crude preparation of a recombinant oligo-isomaltosaccharide synthase (rGTF-S) was prepared from a cell-free extract of Escherichia coli MD124 transformant. Using four homogeneous GTF preparations including previously purified rGTF-S as antigens for immunization, 11 murine hybridomas producing a monoclonal antibody (MAb) were established through the fusion of myeloma cells (P3X63-Ag8-U1) and spleen cells of immunized BALB/c mice. When the immunoreactivities of the resultant MAbs were tested, all five MAbs raised against GTF-I, all three MAbs raised against GTF-T, and two of three MAbs raised against GTF-U reacted specifically with the homologous enzyme alone, while one MAb (B86) raised against GTF-U cross-reacted strongly with all GTFs. Although no MAb monospecific for rGTF-S was obtained, precise recognition of GTF-S was possible using the nonspecific B86 antibody together with the MAbs monospecific for the three glucan synthases. Thus, a set of four typical MAbs (B17, B76, B19 and B86) were successfully used for the identification of gene products expressed in 24 previously constructed E. coli phage clones, and the findings suggested that six phage clones might express a gtfU gene encoding GTF-U which has not been hitherto isolated.

Animals↗
PubMed2000

Inverted papilloma arising in a juvenile.

A 15-year-old man presented with painless, gross hematuria. Excretory pyelography showed a filling defect in the bladder and ultrasonography revealed a solitary bladder tumor. Cystoscopy showed a solitary, papillary tumor on the bladder neck. Transurethral resection was then performed and histological examination showed an inverted papilloma. In addition, the expression of proliferative cellular nuclear antigen and p53 in the surgical specimen were 37.1 and 0%, respectively. Since an inverted papilloma arising during the first two decades of life is quite rare, we herein report the above case and review previous reports.

Adolescent↗
PubMed2000

Circulating GH isoforms and GH bioactivity in preterm neonates.

Among the molecular variants of human GH, the monomeric 22-kD is the predominant isoform, whereas the 20-kD is the second most abundant isoform. Because little is known on the pattern of human GH isoforms in the early postnatal period, we evaluated serum levels of 22-kD GH by an immunofluorometric assay and of 20-kD GH by an ELISA using an anti-20-kD antibody, and measured GH bioactivity with the Nb2 cell bioassay in 19 preterm neonates (gestational age, 32 +/- 0.5 wk; mean +/- SEM) on the fourth and 15th days of life. As control subjects, we studied 19 full-term neonates (gestational age, 39 +/- 0.3 wk) on the fourth day of life and 20 healthy adults, aged 20 +/- 0.3 y. Four-day-old preterm neonates showed significantly higher serum values of 20-kD GH (0.99 - 0.14 ng/mL) than full-term neonates (0.33 +/- 0.07 ng/mL; p < 0.001) and adults (0.09 +/- 0.02; p < 0.0001). Likewise, 22-kD GH and GH levels by Nb2 cell bioassay were also significantly higher (p < 0.001) in preterm than in full-term neonates and young adults. A significant decrease (p < 0.01) in 20-kD, 22-kD, and Nb2-determined GH was observed in preterm neonates on the 15th day of life The percentage of the 20-kD isoform was similar in the preterm infants at the fourth and 15th day, in full-term-infants, and in adults (2.7%, 2.7%, 2.8%, and 3.16%, respectively). Our results indicate that 20-kD GH serum levels change throughout life as regards total amount, but not as regards percentage.

Adult↗