Search PubMed⌕ Search

Biomedical subjects

K Okuda

Publications and source records attributed to K Okuda.

At least 361 records · Page 20Linked to original sources
PubMed1995

Histological observation of the endometrium in repeat breeder cows.

The endometrium plays an important role during attachment and implantation of embryos. Using histological techniques, we evaluated the morphological changes of the endometrium in repeat breeder cows. Endometrial biopsy specimens were obtained from 5 Holstein repeat breeder cows, 5 normally cyclic Holstein cows and 5 normally cyclic Holstein heifers on Days 1 and 8 after estrus. On Day 1, in the repeat breeder cows, the glandular secretions and supranuclear vacuolation were observed, but glandular mitoses were not observed, whereas these secretory characteristics were not observed in the normal cows. However, the appearance of stomal mitoses, stromal edema and pseudodecidual reaction was observed as in the normal cyclic cows. On Day 8, in the repeat breeder cows, the characteristics on the glandular indices were not different from those on Day 1, and were similar to those of the normal cows on Day 8. But, the characteristics on the stromal indices, the stromal mitoses and pseudodecidual reaction, were not observed, although these characteristics were observed in the normally cyclic cows. The presence of advanced morphology in the gland on Day 1 and the stroma on Day 8 indicates that these two events are controlled independently. These endometrial asynchrony might result in cows repeat breeding.

Aging↗
PubMed1995

Effects of osmolarity and amino acids in a chemically defined medium on development of rat one-cell embryos.

Rat one-cell embryos, recovered from naturally mated females, were cultured in a chemically defined medium (R1ECM) under different experimental conditions. When the osmolarity of the medium with a reduced concentration (63.8 mmol l-1) of NaCl was varied by adding different amounts of D-sorbitol, more (79-91%) of the one-cell embryos developed to the four-cell stage at 212-278 mosmol than at 306 mosmol (13%). The greatest proportions of morulae (74%) and blastocysts (60%) were obtained at 246 mosmol. When the medium was supplemented with amino acids in various combinations and the osmolarity adjusted to about 246 mosmol, more (80-98%) of the embryos developed to the morula stage. More blastocysts were obtained in medium supplemented with glutamine (Gln: 80%), minimal essential medium (MEM) essential amino acids (EAA) (90%), Gln+EAA (83%), EAA+MEM nonessential amino acids (NEAA) (83%) or EAA+Gln+NEAA (90%) than in medium without amino acids (59%). Few (3-10%) hatching or hatched blastocysts were observed 120 h after the start of culture in the medium with EAA plus Gln or NEAA. The mean number of cells in blastocysts developed in the medium with EAA+Gln+NEAA was 46.7 +/- 7.2. When a total of 82 morulae or early blastocysts that had developed in culture were transferred to eight pseudopregnant rats on day 4, six recipients into which 62 embryos were transferred maintained their pregnancies beyond day 23, although no deliveries had occurred by day 25 or 26. When the rats were killed, 42 (68%) implantation sites and eight (13%) full-term fetuses with no gross abnormality were observed in the uterine horns.

Amino Acids↗
PubMed1995

Expression of mRNA encoding the prostaglandin F2 alpha receptor in bovine corpora lutea throughout the oestrous cycle and pregnancy.

The abundance of mRNA encoding the PGF2 alpha receptor in bovine corpora lutea at different phases of the oestrous cycle and pregnancy was examined in relation to the number of [3H]PGF2 alpha binding sites. Corpora lutea were removed from cyclic (early: 3-5 days after ovulation; mid-cycle: 8-12 days after ovulation; late: 15-18 days after ovulation; and regressed: 20-21 days after ovulation) and pregnant (early: fetal size 9-13 cm (2-3 months); mid-cycle: fetal size 42-43 cm (5-6 months); and late: fetal size 78-80 cm (8 months)) cows and subjected to total RNA preparation, in situ hybridization and membrane preparation for [3H]PGF2 alpha binding assay. Northern blot analysis demonstrated that expression of PGF2 alpha receptor mRNA progressively increased from the early phase to the late phase of the oestrous cycle, and was markedly reduced at the regressed phase; while constant amounts of mRNA were observed in early and middle pregnant corpora lutea, and there was a significant reduction at late pregnancy. Specific high affinity [3H]PGF2 alpha binding sites with Kd values of 18.3-31.1 nmol-1 were observed in the luteal membrane during the oestrous cycle and pregnancy; this is consistent with the expression of PGF2 alpha receptor mRNA. The number of receptors decreased at the regressed phase and in early pregnancy. These results strongly suggest that PGF2 alpha is involved in not only luteolysis but also luteal functions in both pregnant and nonpregnant cows.

Animals↗
PubMed1995

Pancreatojejunal sutural insufficiency occurring after pancreatoduodenectomy and countermeasures.

Pancreatojejunal sutural insufficiency occurring after pancreatoduodenectomy and countermeasures are discussed. In the Department of Surgery at Kurume University School of Medicine, 318 patients underwent pancreatoduodenectomies. The present study includes 15 of these patients, all of whom had pancreatojejunal sutural insufficiency. The frequency of sutural insufficiency was 4.7%. Five patients had bile duct cancer, 5 had cancer of the papilla of Vater, 2 had a carcinoma of the pancreatic head, 1 each had gallbladder cancer, chronic pancreatitis, and papillitis. Six (40%) of the 15 patients died during hospitalization. The presence or absence of sutural insufficiency was confirmed mainly by radiography and determining the properties and amylase levels of the drainage fluid. There was no significant difference due to the method of anastomosis. End-to-side anastomosis had a rate of 5 (5.9%) of 85 patients, while end-to-end had 10 (4.3%) of 233 patients. The sutural insufficiency was manifested as a major leakage in 6 patients and a minor leakage in 9. The degree of lymph node dissection was D0 in 6.1%, D1 in 1.4%, D2 in 4.8% and D3 in 10.8%, with a high incidence of sutural insufficiency in D3 patients. The pancreatic duct diameter was smaller than 4 mm in 10, 5-7 mm in 4 and over 8 mm in 1 patient. The intraoperative pancreatic findings were a soft pancreas in 8, slightly hard in 3, and hard in 4 patients. Fibrosis of the pancreas was normal to slight in 11 and moderate in 4 patients. Drainage by relaparotomy was performed in 4 of the 6 patients with major leakages to control sutural insufficiency, and the other 2 underwent continuous aspiration with an intraperitoneal drain inserted during the operation. The 9 patients with minor leakage underwent conservative treatment including continuous aspiration via an intraperitoneal drain inserted during surgery, fasting, intravenous hyperalimentation, and antibiotic administration. All of the patients with major leakage died from an associated occurrence of hepatic insufficiency, renal insufficiency, intraperitoneal hemorrhage or diffuse peritonitis during hospitalization. However, 8 of the 9 patients with minor leakage had some healing, and the 1 remaining patient developed a pancreatic fistula. The frequency of pancreatojejunal sutural insufficiency was high in patients with minimal pancreatic fibrosis, with soft pancreatic tissue without dilatation of the pancreatic duct, and with relatively good pancreatic function.

Anastomosis, Surgical↗
PubMed1995

The thrombopoietin receptor c-MPL activates JAK2 and TYK2 tyrosine kinases.

Thrombopoietin (TPO) is a growth and differentiation factor for megakaryocyte-lineage cells. The receptor for TPO, c-MPL, is a member of the hematopoietic cytokine receptor family and has previously been shown to rapidly activate one or more cytoplasmic tyrosine kinases after ligand binding. In this study, we found that activation of the TPO receptor rapidly induced tyrosine phosphorylation of two members of the Jak tyrosine kinase family, JAK2 and TYK2, but not JAK1 or JAK3, in two different factor-dependent hematopoietic cell lines. The activation of both JAK2 and TYK2 was dose- and time-dependent and was associated with rapid tyrosine phosphorylation of a series of STAT proteins including STAT1, STAT3, and STAT5. Gel-shift assays indicated that one or more of these STATs is likely to participate in the formation of specific DNA-binding complexes. The activation of tyrosine kinases and signal propagation through tyrosine phosphorylation are likely to represent important initial steps in mediating the activities of TPO in myeloid cells.

Animals↗
PubMed1995

[The study of continuous arterial infusion chemotherapy with CDDP and 5-FU in patients with hepatocellular carcinoma].

Between Feb. 1992 and April in 1995, 22 patients with hepatocellular carcinoma (10, recurrence; 12, unresectable) received continuous arterial infusion of CDDP and 5-FU via implanted reservoir. For the next five days, 10 mg/body of CDDP and 250 mg/body of 5-FU using arterial infusion were administered. It was discontinued for two days as one course, and 4 courses were basally administered. Patients were divided into 2 groups (6 hours group and 24 hours group) according to the duration of the administration of 5-FU. There were no differences in efficacy rate between the 2 groups (6 hours group, 64%; 24 hours group, 62.5%), but CR (complete response) cases appeared in only the 6 hours group. There were no severe side effects in the 2 groups, but systemic side effects appeared in 6 hours group more often than in 24 hours group. Only in the 24 hours group, 2 patients had the narrowing and obstruction of hepatic artery which was suggested to be caused by intimal injury due to continuous administration of 5-FU. Continuous arterial infusion chemotherapy with CDDP and 5-FU seemed to be effective. Further study on adequate time and volume of administration including pharmacokinetics is needed to enhance the clinical effectiveness of continuous arterial infusion of CDDP and 5-FU.

Aged↗
PubMed1995

Cell surface polysaccharide and protein antigens of an encapsulated Porphyromonas gingivalis 16-1 strain.

We have extracted the cell surface polysaccharide antigen (PS) and protein antigen from an encapsulated and virulent strain of Porphyromonas gingivalis 16-1. The PS was separated from lipopolysaccharide (LPS) by Sephacryl S-300 gel chromatography. It was distinguished from LPS by immunodiffusion with homologous rabbit antiserum. The PS reacted specifically with serogroup b antiserum against P. gingivalis 16-1 and Su63 strains, but not with antisera against serogroup a (ATCC 33277) or serogroup c (W83). The outer membrane protein was extracted with the Zwittergent 3-16 and sarcosyl detergents in a Tris-EDTA buffer. SDS-Page analysis revealed that the extracted protein antigen of P. gingivalis 16-1 contained 2 immunodominant proteins with molecular weights of 41 KDa and 27 KDa.

Antigens, Bacterial↗
PubMed1995

A case of right ventricular dilated cardiomyopathy.

This paper presents a sudden death case of 16-year-old girl. She is assumed to have died of ventricular arrhythmia clinically. On autopsy, the right cardiac ventricle was markedly dilated due to extensive infiltration of fibroadipose tissue and resultant depletion of the myocytes, but there was no full thickness disappearance of the contractile element in any part. Considerable parts of remaining myocytes showed degenerative changes similar to those of dilated cardiomyopathy. The left ventricle was moderately dilated. It showed similar significant degenerative changes to the right ventricle, but the degree was less extensive than the right. These findings do not fill the diagnostic requirements of neither Uhl's anomaly nor parchment heart, which reveal almost total depletion of the right ventricular myocytes. However, the findings were consistent with arrhythmogenic right ventricular dysplasia, in case the concept of the entity is extended, we concluded that it would be better to adopt a term--cardiomyopathy--to this case rather than dysplasia. Because, there were considerable histological evidence of myocardial degeneration suggesting primary myocardial disease rather than congenital defect in nature. We diagnosed, therefore, this case as right ventricular dilated cardiomyopathy, comprising a type of dilated cardiomyopathy whose myocardial lesions predominate in the right compared to the left ventricle.

Adipose Tissue↗
PubMed1994

Expression and characterization of the alpha 2 subunit of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptor channel in a baculovirus system.

Using a baculovirus expression vector system, the alpha 2 subunit of the mouse alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptor (GluR) channel was expressed in Spodoptera frugiperda insect cells. Immunoblotting using the antibody made to the synthetic peptide corresponding to the C-terminus of GluR alpha 2 and [35S]methionine/[35S]cysteine metabolic radiolabeling revealed the major 102-kDa and the minor 98-kDa protein bands. Metabolic radiolabeling with tunicamycin suggested that the two bands correspond to glycosylated and unglycosylated forms, respectively. The recombinant GluR alpha 2 proteins expressed in insect cells were also identified by immunofluorescence staining. The results of [3H]AMPA binding assay using whole cells suggested that, in infected Sf21 cells, binding sites of the GluR alpha 2 proteins were possibly located on the extracellular side. Scatchard analysis of AMPA binding showed the following parameters: Kd = 16 nM, Bmax = 1.9 x 10(5) binding sites per cell or 1 pmol/mg protein in the total particulate fraction. The ligand binding characteristics of the receptors expressed in insect cells were examined. From the effect of various agonists on [3H]AMPA binding of the receptors expressed in insect cells, the rank order potency of agonists was quisqualate > AMPA > L-glutamate > kainate. Thus, the baculovirus-insect cell expression system provides high-efficiency expression of the receptor sufficient to permit structural and functional analyses.

Animals↗
PubMed1994

Inhibition of p21ras activation blocks proliferation but not differentiation of interleukin-3-dependent myeloid cells.

Interleukin-3 (IL-3) induces proliferation of immature myeloid cells and mast cells and prevents programmed cell death (apoptosis) in vitro. These activities are exerted through binding of IL-3 to specific, high affinity receptors that then initiate a series of intracellular signaling events. Among the earliest of these signaling events in an IL-3-dependent cell line such as 32Dcl3 are activation of one or more receptor-associated tyrosine kinases followed by activation of p21ras. In an effort to define the functional role of p21ras activation in mediating the effects of IL-3, we constructed a series of sublines of 32Dcl3 in which a dominant inhibitory mutant of Ha-ras (c-Ha-ras(Asn-17)) was expressed under the control of a steroid-inducible promoter. Steroid treatment (dexamethasone, 1 microM) specifically induced c-Ha-ras(Asn-17) protein and mRNA and blocked IL-3-induced accumulation of p21ras-GTP in 32Dcl3/p21rasN17 cell lines, but not in control cells. Dexamethasone slightly inhibited IL-3-dependent proliferation of control 32Dcl3 cell lines (to 80% of maximum), but it completely blocked proliferation of 32Dcl3/p21rasN17 cell lines and induced cell cycle arrest in G0/G1. This proliferative block could be overcome by cotransfection with v-ras, and was reversible if dexamethasone was washed out. Cells arrested by c-Ha-ras(Asn-17) were viable in culture for > 2 weeks, despite their inability to proliferate. Notably, however, these cells remained dependent on IL-3 for viability and initiated apoptosis within 18 h of IL-3 deprivation. Finally, granulocyte colony-stimulating factor-induced differentiation of 32Dcl3/p21rasN17 cells to neutrophils was not affected by steroid-induced expression of c-Ha-ras(Asn-17) and did not require removal of IL-3. These results suggest that IL-3-induced proliferation and maintenance of cell viability are either initiated through separate signal transduction pathways or require different degrees of p21ras activation. Similarly, granulocyte colony-stimulating factor-induced neutrophil differentiation is not blocked by expression of c-Ha-ras(Asn-17).

Cell Cycle↗
PubMed1994

Crkl is the major tyrosine-phosphorylated protein in neutrophils from patients with chronic myelogenous leukemia.

The Philadelphia chromosome (Ph1), detected in virtually all cases of chronic myelogenous leukemia (CML), is formed by a reciprocal translocation between chromosome 9 and 22 that fuses Bcr-encoded sequences upstream of exon 2 of c-Abl. This oncogene produces a fusion protein, p210bcr-abl, in which the Abl tyrosine kinase activity is elevated. Using anti-phosphotyrosine immunoblotting, we have compared the pattern of phosphotyrosine-containing proteins from freshly prepared neutrophils of patients in the stable phase of CML to normal controls. The only consistent difference was the presence of a 39-kDa tyrosine-phosphorylated protein in 18 out of 18 neutrophil samples from CML patients that was not seen in normal controls. This same protein, as assessed by two-dimensional anti-phosphotyrosine immunoblotting, was also present in cell lines expressing p210bcr-abl, including K562 cells. Using K562 cells as a source of protein, the 39-kDa protein was purified and identified by microsequencing as Crkl, an SH2/SH3 adaptor protein related to the crk oncogene of the avian sarcoma virus, CT10. A direct interaction between Crkl and Abl has also been shown using a yeast two-hybrid screen.

Adaptor Proteins, Signal Transducing↗
PubMed1994

Intracellular receptor-type transcription factor, LasR, contains a highly conserved amphipathic region which precedes the putative helix-turn-helix DNA binding motif.

We have cloned and sequenced the lasR gene, which is involved in the transcriptional activation of several pathogenic factors, from Pseudomonas aeruginosa IFO3455 and PA103. These clones were predicted to be an open reading frame of 239 amino acids as reported for the PAO1 strain. There is only a single base change resulting in an amino acid exchange from M145 (PAO1) to I (IFO3455). PA103 DNA differs with PAO1 DNA in two bases resulting in only a single amino acid substitution from R179 to W. When the IFO3455 LasR was expressed in a PA103 strain which is known to be LasR defective, proteinase gene activation was detected, however, when PA103 LasR was expressed, no enhancement was measurable. From these results, it appears that the amino acid substitution of R179 to W inactivated LasR activity. This substitution is located in the highly conserved sequence found in many transcription factors, including sigma factors, and may disrupt amphipathic alpha-helix, predicted for the 176 to 189 region, which precedes the putative helix-turn-helix DNA binding motif. We presumed that these three helices may contribute to specific DNA binding.

Amino Acid Sequence↗
PubMed1994

Further oxidation of hydroxycalcidiol by calcidiol 24-hydroxylase. A study with the mature enzyme expressed in Escherichia coli.

The coding region of the cDNA for rat kidney calcidiol 24-hydroxylase (P450cc24), which is involved in calcium homeostasis in animals, was inserted into an expression vector pKK223-3. The recombinant plasmid was formed in a specific manner without deletion or substitution of any parts of the coding region of the cDNA. When the resulting plasmid was introduced into Escherichia coli JM109, the recombinant cells produced a protein which was immunoreactive to an antibody against P450cc24. When the cell-free extract of the transformed cells was incubated with calcidiol together with bovine adrenodoxin and NADPH-adrenodoxin reductase, not only hydroxycalcidiol but also other metabolites such as oxocalcidiol and oxohydroxycalcidiol were produced. Similarly, calcitriol was converted not only to calcitetrol but also to oxocalcitriol and oxohydroxycalcitriol. These results indicate that a single enzyme expressed in the bacteria is responsible for all these successive reactions.

Animals↗
PubMed1994

NF-kappa B and Sp1 regulate transcription of the human monocyte chemoattractant protein-1 gene.

Expression of the human monocyte chemoattractant protein-1 (hMCP-1) is ubiquitous in various cell types and is increased by a wide variety of stimuli. We initially found that the effects of various stimuli, including IL-1 beta, TNF-alpha, and 2-O-tetradecanoylphorbol 13-acetate, on the expression of hMCP-1 mRNA were quite different among A172 glioblastoma cells, HT1080 fibrosarcoma cells, and SKLMS1 leiomyosarcoma cells. These findings suggested that hMCP-1 expression is regulated both in a stimulus-specific and a tissue-specific manner. To elucidate the mechanism underlying this stimulus-specific and tissue-specific regulation, we isolated a hMCP-1 5'-flanking genomic DNA fragment and sequenced it extensively up to bp 3011 upstream from the transcriptional start site. Among many putative cis-elements, we identified two cis-elements critical for the transcription of the hMCP-1 gene. The first element is a remote kappa B binding site located far upstream between bp -2612 and -2603 that was important for IL-1 beta-, TNF-alpha-, and 2-O-tetradecanoylphorbol 13-acetate-induced enhancer activity. Mutation at the kappa B consensus site resulted in a complete loss of these stimulus-induced enhancer activities. The second element is a GC box located between bp -64 and -59 that was important for the maintenance of basal transcriptional activity. Overexpression of rSp1 resulted in increased hMCP-1 transcriptional activity, possibly suggesting the role of Sp1 in controlling basal hMCP-1 transcription via this GC box. These results together indicate that hMCP-1 expression is controlled by at least two distinct regulatory elements: a kappa B site and a GC box that seem to be associated with stimulus-specific and tissue-specific regulation, respectively.

Base Sequence↗