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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 757 records · Page 42Linked to original sources
PubMed1995

[Current concept and problems of urinary diversion. 2. Selection of operation: reservoir].

The Kock continent urinary reservoir was constructed in 12 patients from 1988 to 1990 followed by the Indiana continent urinary reservoir in 14 patients thereafter. There were no perioperative death in either group. The period of postoperative follow-up was 11 approximately 70 months, with a mean of 58.9 months. Several modifications of the operative technique were made to the original Kock pouch, but stone formation was observed in 5 patients (42%), resulting from foreign materials permanently in contact with urine. In the Indiana pouch group with a mean postoperative follow-up period of 26.8 months (range 11 approximately 43 months), wound infection occurred in the initial 4 patients and difficulty of catheterization in the other 4 patients. The serum electrolyte values were found to be within the normal limits during the follow-up period in both groups, but, mild acidosis occurred in 2 patients. Patients with urinary diversion demonstrated mild azotemia (P = 0.02) despite similar serum creatinine levels and an increase in urine pH (P = 0.006) postoperatively. Asymptomatic bacteriuria was demonstrated in 22 of the 26 (83%) patients with the reservoir, but only 5 patients had significant pyuria. Our clinical experience suggests that the Indiana pouch is a more reliable method than the Kock pouch to construct a continent urinary reservoir.

Female↗
PubMed1995

Touch-inducible genes for calmodulin and a calmodulin-related protein are located in tandem on a chromosome of Arabidopsis thaliana.

Genes for calmodulin and calmodulin-related proteins in Arabidopsis are up-regulated by a variety of physical stimuli, which include rain, wind and touch [Braam and Davis (1990) Cell 60: 357]. We have isolated five genes for calmodulin (AtCAL1, 2, 3, 5, 6) and one gene for a calmodulin-related protein (AtCAL4) from an Arabidopsis genomic library. Touch stimulus of Arabidopsis plants induces the accumulation of mRNA transcribed from AtCAL4 and AtCAL5, but not from the other isolated genes. The two touch-inducible genes are arrayed in tandem with a short intergenic region of 700 bp but they show different organ-specific patterns of expression.

Arabidopsis↗
PubMed1995

Characteristics of MHC antigen expression and tumor-infiltrating mononuclear cells in renal cell adenomas and carcinomas.

We compared the expression of major histocompatibility complex (MHC; HLA class I and II) antigens and the presence of tumor-infiltrating mononuclear cells presenting S100 protein (S100), CD68 antigen, or CD45RO antigen in formalin-fixed, paraffin-embedded tissue sections of 10 renal cell carcinomas and 9 renal cell adenomas using immunohistochemistry. The expression of beta 2-microglobulin (B2MG) as an HLA class I antigen in all 10 cases (100%) and that of HLA-DR/alpha as an HLA class II antigen in 7 of 10 cases (70%) of carcinoma was stronger than that in the adjacent proximal convoluted tubule, but was respectively not different to weaker in 8 of 9 cases and not different to markedly weaker in all cases of adenoma. Furthermore, there was comparatively dense infiltration by S100(+) antigen-presenting cells in the carcinomas, but almost none in the adenomas and generally dense infiltration by CD45RO(+) T cells and CD68(+) macrophages in the carcinomas, but little to none in the adenomas. We concluded that the generally enhanced expression of MHC antigens in carcinomas must be an immunophenotypic deviation from not only the adjacent proximal convoluted tubule but also adenomas, and that the predominant infiltration of antigen-presenting cells, T cells and macrophages in the carcinomas, but not in the adenomas, reflects the anti-cancer immune reaction.

Adenoma↗
PubMed1995

The effects of endothelin-1 on intraocular pressure and pupillary diameter in rabbits.

Endothelin-1 (ET-1) reduced intraocular pressure (IOP) in animals when administered topically. The time-course of IOP changes induced by ET-1, however, has not been fully documented. We studied the IOP response to different doses of intravitreally injected ET-1 ranging from 10(-7) to 10(-4) M in rabbits. In each animal one eye received 20 muL of ET-1 solution and the contralateral eye received the same amount of vehicle in a randomized, masked fashion. IOP was measured by a pneumatonometer prior to and periodically for at least 72 hours after the intravitreal injection. ET-1 in 10(-4) and 10(-5) M concentration elicited an IOP response consisting of an initial rise of 1- to 2-hour duration, and a subsequent prolonged reduction lasting for more than 72 hours. The use of 3 x 10(-6) and 10(-6) M solutions resulted in a prolonged IOP reduction without an early IOP rise. No significant IOP change was induced by 10(-7) M solution or the vehicle. No change was observed in pupillary diameters after injection of ET-1 in any dose. The aqueous prostaglandin E2 concentration was significantly increased at both 1 and 24 hours after 10(-5) M ET-1 injection.

Animals↗
PubMed1995

Synthesis and properties of oligo-omega-amino acids derivatives containing nucleosides.

Nucleic acid analogs, that consist of oligo-omega-amino acids as main chains were synthesized. At first, hydroxyl group of deoxy and ribonucleic acid was converted into amino or carboxylic acid group. Then, amino acid derivatives containing aminonucleoside or nucleoside-5'-carboxylic acid at alpha-position were synthesized. Amino acids used in this paper were L-glutamic acid, L-2-amino adipic acid (L-homo glutamic acid), L-ornithine, and L-lysine. These amino acid derivatives containing nucleoside were oligomerized by activated ester methods and Merrifield's solid phase synthesis. The properties of these analogs were studied and compared with oligo-alpha-amino acid derivatives containing nucleoside at omega-position.

Amino Acids↗
PubMed1995

The effects of ETB receptor-selective agonist on IOP and blood-aqueous barrier in rabbit eyes: role of cyclooxygenase products.

The authors have reported that ET-1 and ETB receptor agonist, sarafotoxin S6c (STX-S6c), caused prolonged intraocular pressure (IOP) reduction in rabbit eyes in a dose-dependent fashion when injected intravitreally. The purpose of this study was to determine the effects of STX-S6c on the blood-aqueous barrier and also the possible role of cyclooxygenase products in modulating IOP. Indomethacin, a cyclooxygenase inhibitor (50 mg/kg), or its placebo was administered intraperitoneally 1 hour before or 1 hour before and 4 hours after the intravitreal injection of 0.5 micrograms of STX-S6c into one eye in a group of albino rabbits. The fellow eye received the vehicle only. IOP was measured prior to and periodically up to 120 hours after the injection using a calibrated pneumatonometer. One hour and 24 hours following the injection of STX-S6c (0.5 micrograms) with or without indomethacin, approximately 100 microL of aqueous humor was withdrawn by paracentesis. Protein concentration was measured by Lowry's method and PGE2 concentration was determined by radioimmunoassay. Both single and double dosings of indomethacin failed to prevent the IOP reduction caused by STX-S6c. The eyes injected with STX-S6c exhibited a significant elevation of both PGE2 and protein concentration at both 1 and 24 hours after injection. Pretreatment with indomethacin could significantly suppress the PGE2 and protein content of aqueous humor at both 1 and 24 hours after injection. ETB receptor agonist, STX-S6c, appears to induce the IOP reduction without affecting the cyclooxygenase pathway or disrupting the blood-aqueous barrier.

Animals↗
PubMed1994

Defective T cells from gld mice play a pivotal role in development of Thy-1.2+B220+ cells and autoimmunity.

The gld mouse represents a fascinating animal model of autoimmune disease, which is characterized by massive development of Thy-1.2+B220+ CD4-CD8- cells. These cells thus have double positive markers for T and B cells, but are double negative for CD4 and CD8 markers and are thus designated DN cells in the present context. An additional important feature in gld mice is a defect in expression of Fas ligand. To investigate the regulatory role of bone marrow-derived cells for the development of these DN cells and of gld autoimmunity, we constructed chimeric mice transplanted with fetal liver cells or fetal thymus from gld mice into nonirradiated severe combined immunodeficient (SCID) mice. These chimeric mice regenerated, developed both these DN cells and the gld autoimmune syndrome and also generalized lymphoproliferative disorders. However, when fetal liver cells from both gld and non-gld mice (C57BL/10 Thy-1.1 mice) were co-transplanted into SCID mice, the development of DN cells was apparently inhibited. Further, this inhibition was also seen in SCID mice that had been grafted with both gld and non-gld fetal thymus revealing the pivotal role played by T cells in development of DN cells. When B cells purified from non-gld (C3H+/+) mice were transplanted into SCID mice grafted with gld fetal thymus, the development of DN cells was not inhibited. Taken together, these findings indicate that T cells from non-gld mice inhibit the expression of gld features, e.g., lymphoproliferation, immune-based nephritic disease, and autoantibody production. These findings also suggest that the Fas ligand is selectively expressed on T cells.

Animals↗
PubMed1994

Kinetic analysis of plasminogen activation by staphylokinase/plasminogen complex in the presence of fibrin.

Staphylokinase (SAK) expresses plasminogen activator activity by forming a complex with plasminogen. In order to elucidate the mechanism for the expression of enzymatic activity of the complex, a cross-linked staphylokinase/plasminogen (SAK/plg) complex was produced with disuccinimidyl suberate, and its enzymatic characteristics were compared with those of a streptokinase/plasminogen (SK/plg) complex. SAK/plg complex and SK/plg complex showed a band with a molecular weight of 110 kDa and 140 kDa by SDS-PAGE under non-reduced condition, respectively. Both complexes exhibited plasminogen activator activity in a concentration-dependent manner on fibrin film and synthetic chromogenic substrate assay. The kinetic analysis of enzymatic activity of both complexes was performed. The plasminogen activator activity of SAK/plg complex was enhanced about 5-fold in the presence of FCB-2. However, SK/plg complex showed only 1.7-fold increase in the presence of FCB-2. These findings indicate that the SAK/plg complex reacts with fibrin, and efficient plasminogen activation is induced on fibrin surface.

Amino Acid Sequence↗
PubMed1994

Effects of alpha 2-plasmin inhibitor on plasminogen activation by staphylokinase/plasminogen complex.

Using a stable cross-linked SAK/plg complex, the effects of alpha 2-plasmin inhibitor on plasminogen activation by SAK were investigated. alpha 2-Plasmin inhibitor inhibited dose-dependently plasminogen activation by the SAK/plg complex. When FCB-2 or EACA was added to the reaction mixture of SAK/plg complex and alpha 2-plasmin inhibitor, the inhibitory activity of alpha 2-plasmin inhibitor was abolished and the enzymatic activity of the complexes was restored. alpha 2-Plasmin inhibitor inhibited the activity of the SK/plg complex, but neither FCB-2 nor EACA restored the plasminogen activator activity in the mixture of SK/plg complex and alpha 2-plasmin inhibitor. Using 125I-labeled SAK/plg complex or SK/plg complex, the reaction of the complex with alpha 2-plasmin inhibitor was analyzed. The SAK/plg complex produced a new complex with alpha 2-plasmin inhibitor. The formation of a new high molecular weight complex with alpha 2-plasmin inhibitor was abolished by both EACA or FCB-2. With regard to the SK/plg complex, neither EACA nor FCB-2 suppressed the complex formation with alpha 2-plasmin inhibitor. These findings indicate that the SAK/plg complex binds to fibrin, and that this complex expresses plasminogen activator activity without being affected by alpha 2-plasmin inhibitor.

Amino Acid Sequence↗
PubMed1994

Involvement of LDL receptor in the proliferation of vascular smooth muscle cells.

To study the involvement of the low-density lipoprotein (LDL) receptor in the growth of vascular smooth muscle cells (VSMC), we compared the proliferation of cultured VSMC from Watanabe heritable hyperlipidemic (WHHL) rabbits, which lack the LDL receptor, and VSMC from normal Japanese white rabbits in response to platelet derived growth factor (PDGF). The increase in the number of VSMC from WHHL rabbits in response to PDGF (10(-8) M) was significantly lower than that of VSMC from normal rabbits. PDGF stimulated the synthesis of DNA in VSMC from both normal rabbits and WHHL rabbits, but the response was significantly lower in the latter. To determine the involvement of the LDL receptor in the decreased mitogenic response of WHHL rabbit VSMC, we used an anti-LDL receptor monoclonal antibody (MAb) to normal rabbit VSMC; DNA synthesis of VSMC was stimulated by PDGF, but the effect was significantly blocked by the anti-LDL receptor MAb. Mitogen-activated protein (MAP) kinase activity in normal rabbit VSMC was increased by exposure to PDGF, but the effect was significantly suppressed in the presence of the MAb. The anti-LDL receptor MAb markedly inhibited LDL binding to the surface of normal rabbit VSMC. These results suggest that the LDL receptor influences the proliferation of VSMC and thus might be involved in the pathogenesis of atherosclerosis.

Animals↗
PubMed1994

Isolation of human nm23 genomes and analysis of loss of heterozygosity in primary colorectal carcinomas using a specific genomic probe.

Genomic clones of nm23-H1 and -H2 were isolated. The nm23-H1 and -H2 genes were located in a tandem array 4 kilobases apart. Each genome contained 5 exons and most of the splicing sites in the exon-intron junctions of two isotypes were essentially identical. A probe derived from intron 4 of nm23-H1 was used to examine the loss of heterozygosity (LOH) in primary colorectal carcinomas. Twenty-nine of 42 samples were informative and LOH was found in 3 of these 29. In all three samples with LOH, cancer tissues expressed lower levels of nm23-H1 mRNA when compared with those without LOH.

Amino Acid Sequence↗
PubMed1994

Erythropoietin induces tyrosine phosphorylation and activation of phospholipase C-gamma 1 in a human erythropoietin-dependent cell line.

Erythropoietin (Epo) is the major regulator of the proliferation and differentiation of erythroid precursors through interaction with its receptor (Epo-R). Although Epo-R lacks a tyrosine kinase consensus sequence within its intracellular domain, the addition of its ligand to Epo-responsive cells, UT-7/Epo, induces the rapid and transient tyrosine phosphorylation of 145-, 130-, 80-, and 40-kDa cellular proteins. Tyrosine phosphorylation of these proteins occurred dose- and time-dependently. We showed that the tyrosine phosphorylated 145- kDa protein is identical to phospholipase C-gamma 1 (PLC-gamma 1). Tyrosine phosphorylation of this protein is detectable within 30 s and almost reaches the maximum at 1 min. This can last up to 10 min and declines thereafter. Additionally, in Epo-stimulated cells, PLC-gamma 1 become physically associated with 80- and 40-kDa proteins which have been tyrosine-phosphorylated in response to Epo. The activity of PLC-gamma 1 was also investigated using inositol 1,4,5-trisphosphate (Ins-P3) as an indicator. We found that stimulation of UT-7/Epo cells with Epo induces a significant accumulation of Ins-P3. This effect is dose-dependent and occurs very rapidly. The production of Ins-P3 can explain the Epo-induced mobilization of calcium from intracellular stores in these cells. These results demonstrate that Epo induces tyrosine phosphorylation and activation of PLC-gamma 1 to produce Ins-P3 and then it mobilizes calcium from intracellular stores. This signal transduction pathway may play a role in regulating the proliferation of erythroid cells.

Calcium↗
PubMed1994

The identification of Escherichia coli ispB (cel) gene encoding the octaprenyl diphosphate synthase.

The gene located upstream of the nlp gene at min 69 on the chromosome of Escherichia coli was cloned from the plasmid pLC7-42 constructed by Clarke and Carbon. The extract of the strain harboring the plasmid containing this gene showed increased activity of the prenyltransferase. The product of the enzyme reaction was analyzed by two systems of the thin-layer chromatography and shown to be the phosphate ester of all-E-octaprenol. These results suggested that the gene was the structural gene for the octaprenyl diphosphate synthase which supplied the precursor of the side chain of the isoprenoid quinones.

Alkyl and Aryl Transferases↗
PubMed1994

Genotypical classification of neutrophil Fc gamma receptor III by polymerase chain reaction-single-strand conformation polymorphism.

We classified the genotype of neutrophil Fc gamma receptor III (FcRIII) (CD16) with a new method. Genomic DNA from mononuclear cells of 39 unrelated healthy donors (13 NA1/NA1, 13 NA2/NA2, and 13 NA1/NA2 typed serologically) were subjected to polymerase chain reaction (PCR) to amplify the polymorphic third exon of the FcRIII genes. The PCR products were heat denatured, electrophoresed, and visualized by silver staining. Allelic differences were detected by distinctive electrophoretic patterns of each single strand, depending on their sequence specific conformations (single-strand conformation polymorphism [SSCP]). The genotypes of neutrophil FcRIII determined by this method were consistent with the phenotypes of NA antigens determined by serologic examinations. These results indicate that the PCR-SSCP system is a very useful tool for genotyping of the neutrophil FcRIII.

Base Sequence↗
PubMed1994

Pseudohypoparathyroidism-associated spinal stenosis.

STUDY DESIGN: Pseudohypoparathyroidism associated with disorders of the spine is rarely reported. In this report, the authors present a case of pseudohypoparathyroidism in a 41-year-old man who had narrow spinal canal and multiple disc herniation in the cervical spine. SUMMARY OF BACKGROUND DATA: The patient had progressive spastic tetraplegia due to cervical cord compression caused by multiple disc herniations at the C3-C4, C4-5, and C5-C6 levels in the developmentally narrow spinal canal. Based on the features of Albright's osteodystrophy, serum laboratory results, and an Ellsworth-Howard test, the diagnosis of pseudohypoparathyroidism, type I was confirmed. METHODS: The patient underwent expansive laminoplasty at C3 through C6 levels. RESULTS: His symptoms have gradually improved during the 1-year and 6-month periods after the surgery. CONCLUSIONS: A case of pseudohypoparathyroidism-associated spinal stenosis was reported.

Adult↗
PubMed1994

Development of an instrument to measure postmortem lividity and its preliminary application to estimate the time since death.

A degree of postmortem lividity was related to a subcutaneous hemoglobin concentration, which can be measured by using light absorption. On the basis of this theory, the authors have developed an instrument utilizing a light to measure the degree of postmortem lividity. By using 42 corpses whose postmortem intervals were known, the authors examined the relationship between the actual postmortem intervals and the measurements, and found that there was significant correlation between them.

Adult↗