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Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 235 records · Page 13Linked to original sources
PubMed1999

Assisted reproduction for infertile patients with 9 + 0 immotile spermatozoa associated with autosomal dominant polycystic kidney disease.

We investigated the clinical feature of patients with totally immotile spermatozoa due to 9 + 0 ultrastructural flagellar defects and polycystic kidney disease. We also tried to establish the feasibility of applying modern assisted reproduction technology (ART) in these patients. During 6-year interval a total of 1956 Japanese men were referred to the male infertility clinic. Of them, 16 were diagnosed to have immotile spermatozoa and four of them exhibited axonemal 9 + 0 defects in the sperm flagella. These four also had autosomal dominant polycystic kidney disease (ADPKD). Intrauterine insemination (IUI) and conventional in-vitro fertilization and embryo transfer failed to achieve fertilization. Intracytoplasmic sperm injection (ICSI) with 100% immotile spermatozoa was performed in all four cases. Two-pronuclear fertilization was obtained in 27 of the 70 (38.6%) of the successfully injected oocytes, but no pregnancy resulted. In one case, a few motile spermatozoa were present at the second cycle of ICSI, a pregnancy was successfully achieved using these spermatozoa. While immotile spermatozoa from patients with the axonemal 9 + 0 defect achieved fertilization by ICSI, the embryos failed to develop. Our results indicate that the central microtubules may play a role in fetal development. Since the 4 patients with 9 + 0 defects also had ADPKD, the genetic linkage between these two conditions should be studied by molecular biological methods so as to aid our ability to counsel such patients.

Cytoplasm↗
PubMed1999

Klinefelter's syndrome in the male infertility clinic.

The clinical features of patients with Klinefelter's syndrome attending a male infertility clinic have been investigated in order to consider their assisted reproduction treatment options. Over 12 years, a total of 148 patients with sterility due to azoospermia had Klinefelter's syndrome. Eight patients were shown by fluorescence in-situ hybridization (FISH) on metaphase spreads to be mosaic (46,XY/47,XXY), and 140 patients showed only 47,XXY. Small testes were observed in 95% of patients and gynaecomastia was seen in 12.4%. Half of the patients showed hypergonadotrophic hypogonadism, while others showed normogonadism (usually hypergonadotrophic). Spermatozoa were observed in semen from one patient with mosaicism and one without. Three-colour FISH revealed hyperploidy in 2.7% and 2.3% of these spermatozoa respectively. Multiple-site testicular biopsies in five recent patients were performed and yielded a specimen with round and elongated spermatids in one patient with 47,XXY karyotype. This sample was cryopreserved for future intracytoplasmic sperm injection. At follow-up, 46% of couples had chosen artificial insemination with donor sperm, and none had chosen adoption. Two patients developed testicular tumours, one a mature teratoma and the other a Leydig cell tumour. Two patients required androgen replacement therapy.

Adult↗
PubMed1999

Rapid down-regulation of CD63 transcription by progesterone in human endometrial stromal cells.

Differentiation of endometrial stromal cells (decidualization) plays a crucial role in embryo implantation and maintenance of pregnancy. While progesterone is a key factor in regulating endometrial cell decidualization, the molecular mechanisms remain unclear. In the present study, we investigated the effect of gene transcription in human endometrial stromal cells (ESC) by progesterone, oestrogen or vehicle using the polymerase chain reaction-based differential display methodology. A transcript which is down-regulated by progesterone, but not by vehicle and oestrogen, was identified from a differential display band and the progesterone sensitivity of its expression was verified in Northern blot analysis. The level of the gene expression in progesterone-treated ESC was approximately 60% of that in the vehicle- and oestrogen-treated ESC. This cDNA was revealed to be human CD63 antigen, a recently identified member of the transmembrane 4 superfamily. The inhibitory effect of progesterone is observed within 30 min after hormone treatment. In human endometrium, CD63 mRNA levels were significantly decreased (P < 0.05) during the secretory phase compared with levels during the proliferative phase. This down-regulation of CD63 in vivo elevated levels of progesterone in the secretory phase. These results suggest that CD63 transcription is down-regulated by progesterone in human endometrium.

Adult↗
PubMed1999

Comparative study of two ribozymes and DNA-enzyme against the same RNA target.

Two ribozymes, hammerhead ribozyme and hairpin ribozyme, and a DNA-enzyme were designed to cleave a same RNA target, the same site of the rat complement regulatory factor 512 antigen mRNA. The kinetic properties of these RNA-cleaving enzymes were measured and compared under the same conditions, using multiple turnover kinetics and competition kinetics. The catalytic efficiencies of these enzymes, and also the order of these enzymes will be discussed.

Animals↗
PubMed1999

Does intensive perioperative dialysis improve the results of coronary artery bypass grafting in haemodialysed patients?

BACKGROUND: Between January 1996 and April 1998, 17 chronic haemodialysed patients underwent coronary artery bypass grafting (CABG). Two of them simultaneously had valve replacement. METHODS: Except for two cases in which CABG was performed in an emergency, 15 patients (CRF group) received 3 consecutive days of haemodialysis in the preoperative period, intraoperative haemodialysis connected to cardiac pulmonary bypass (CPB) and continuous hemodiafiltration in the early postoperative period. The perioperative clinical parameters of the CRF group were compared with those of 17 age-matched patients with normal renal function undergoing CABG as the control (NRF group). RESULTS: When the perioperative variables were compared, no significant differences were seen in total operation time and CPB time, but we noted significant increases in the mean volume of transfused blood in the 6 perioperative days, postoperative intubation time, postoperative fasting time, and time spent in the intensive care unit. Levels of central venous pressure, systolic blood pressure, respiratory index (PaO2/FiO2) and daily fluid balance of the CRF group were the same as the control group in the early postoperative period. In addition, the levels of serum creatinine, urea nitrogen, potassium and hematocrit of CRF group remained almost constant in the early postoperative period. After all, the hospital morbidity of the CRF group was not more serious than that of the NRF group, and hospital mortality of the CRF and NRF groups was 0%. CONCLUSIONS: Our intensive perioperative dialysis programme could successfully manage the perioperative clinical course of haemodialysed patients undergoing CABG.

Coronary Artery Bypass↗
PubMed1999

Biochemical properties potentially rendering human brain microvasculature vulnerable to proteolytic injury associated with the use of fibrinolytic drugs.

BACKGROUND: Determinants of predisposition to intracranial bleeding in response to the administration of thrombolytic drugs have not yet been well characterized. OBJECTIVE: To delineate factors involved, by characterizing susceptibility of human cerebral microvascular endothelium (HCME) to injury associated with inflammatory cytokines, levels of which are typically elevated in blood in patients who have suffered a myocardial infarction or stroke and been treated with thrombolytic drugs. METHODS: Elaboration of fibrinolytic system proteins by HCME exposed either to interleukin-1 beta or to tumor necrosis factor-alpha (TNF) in serum-free medium for 24 h was characterized. Cell-conditioned medium was assayed for tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and plasminogen activator inhibitor type 1--(PAI-1) by enzyme-linked immunosorbent assay. To determine whether the induction of u-PA was mediated by oxygen-centered radicals, the following were added to media: superoxide dismutase (a scavenger of O2-.), catalase (a scavenger of O2-. and H2O2) and dimethylthiourea (a scavenger of OH.). RESULTS: Interleukin-1 beta had no effect upon elaboration of fibrinolytic system proteins by HCME. By contrast, TNF selectively increased elaboration of u-PA. Accumulation of t-PA and PAI-1 remained unchanged. Accumulation of u-PA was inhibited by cycloheximide, implying that there was a requirement for protein synthesis. Dimethylthiourea abolished the increase elaboration of u-PA induced by TNF completely, catalase did so partially, and SOD did not do so at all. CONCLUSION: The propensity of HCME to elaborate u-PA rather than PAI-1 appears to render cerebral microvasculature particularly vulnerable to proteolytic attack in settings in which inflammatory cytokines are elaborated locally or in which their concentrations in blood are elevated.

Brain↗
PubMed1999

Lactobacillus paralimentarius sp. nov., isolated from sourdough.

Six strains of lactic acid bacteria isolated from sourdough were characterized taxonomically. They were Gram-positive, catalase-negative, facultatively anaerobic rods that did not produce gas from glucose. Morphological and physiological data indicated that the strains belong to the genus Lactobacillus and they were similar to Lactobacillus alimentarius in phenotypic characteristics. These strains shared the same phenotypic characteristics and exhibited intragroup DNA homology values of over 89.8%, indicating that they comprised a single species. The G + C content of the DNA for the strains was 37.2-38.0 mol%. The 16S rRNA sequence of representative strain TB 1T was determined and aligned with that of other Lactobacillus species. This strain was placed in the genus Lactobacillus on the basis of phylogenetic analysis. L. alimentarius was the most closely related species in the phylogenetic tree and this species also showed the highest sequence homology value (96%) with strain TB 1T. DNA-DNA hybridization indicated that strain TB 1T did not belong to L. alimentarius. It is proposed that these strains are placed in the genus Lactobacillus as a new species, Lactobacillus paralimentarius sp. nov. The type strain of L. paralimentarius is TB 1T, which has been deposited in the Japan Collection of Microorganisms (JCM) as strain JCM 10415T.

Bacterial Typing Techniques↗
PubMed1999

Characterization of mouse DAF on transfectant cells using monoclonal antibodies which recognize different epitopes.

Several membrane proteins prevent host cells from homologous complement attack. In humans, one such protein, decay-accelerating factor (DAF), exists as two isoforms, a GPI anchored form and a secreted form, which are generated by alternative splicing. DAF in mouse is also expressed as two isoforms, a GPI anchored form (GPI-DAF) and a transmembrane form (TM-DAF), which are produced from two separate genes. In this study, we transfected cDNA of mouse GPI-DAF or TM-DAF into Chinese hamster ovary (CHO) cells. Both isoforms of DAF on CHO cells were shown to regulate mouse complement C3 deposition mediated by the classical and alternative pathways and the inhibitory activity of both isoforms was species restricted. The two mouse DAF isoforms were effective against rat complement but not against human and guinea pig complement. Furthermore, we produced hamster mAbs to mouse DAF using GPI-DAF transfectant cells and established seven unique mAbs (RIKO-1-7). Western blotting analysis using RIKO-3, which reacts with both GPI-DAF and TM-DAF, and RIKO-4, which is an anti-GPI-DAF specific mAb, indicated that GPI-DAF was expressed on erythrocytes, spleen and testis, and that TM-DAF was expressed only in testis.

Animals↗
PubMed1999

mRNA expression of complement components and regulators in rat arterial smooth muscle cells.

The presence of C5b-9 complexes, some complement regulators, and abundant cytokines in atherosclerotic lesions has been reported. However, it is unclear whether these complement-associated proteins are produced by vascular smooth muscle cells (SMCs) and how they are influenced by the cytokines. In the present study, we demonstrated, by the reverse transcription-polymerase chain reaction method, the mRNA expression of complement components (C3, C4, and C5) and membrane regulators (decay-accelerating factor, membrane cofactor protein, Crry, and CD59) in cultured SMCs derived from the rat carotid artery. The expression of C9 mRNA was also induced upon stimulation by interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and/or lipopolysaccharide (LPS). Northern blot analysis showed that the mRNA expression of C3, C4, DAF and Crry was up-regulated, but that of CD59 was down-regulated by IFN-gamma, TNF-alpha and/or LPS alone or by synergy. The increase of C3 mRNA by TNF-alpha or LPS and that of C4 mRNA by IFN-gamma was induced in a dose-dependent manner. The results indicate that the arterial SMCs of rat have the ability to produce complement components and regulators, which is affected by cytokines and/or LPS. Since atherosclerosis is characterized by the intimal proliferation of SMCs, the complement system including its regulators may be involved in the pathogenesis of the disease.

Animals↗
PubMed1999

Arginine carboxypeptidase (CPR) in human plasma determined with sandwich ELISA.

There are two types of carboxypeptidases present in human blood, carboxypeptidase N (CPN) and arginine carboxypeptidase (CPR). CPR is generated during coagulation from a precursor (proCPR) which can be converted to the active form by trypsin in vitro. Since it is difficult to distinguish the two types of carboxypeptidases in human blood by the measurement of enzyme activity, we established a quantitative sandwich ELISA by which CPR can be quantitated. The amount of CPR in plasma, fresh serum and heated serum were essentially the same. Therefore the ELISA assay does not distinguish proCPR, activated CPR and inactivated CPR. With the ELISA method, CPR was quantitated in plasma from fifty patients with rheumatoid arthritis and eleven patients with severe hepatitis as well as healthy individuals. The amount of CPR in plasma obtained from patients with rheumatoid arthritis was not found to be lower than that of normal subjects. Furthermore, the patients who suffered severe hepatitis and had very low levels of CPR-total were fatal. This suggests that a decrease of CPR level might be a good indication of a patient's prognosis to death by hepatitis.

Antibodies, Monoclonal↗
PubMed1999

Human IgM monoclonal antibody to ganglioside GM2 and complement suppress virus propagation in ex vivo cultures of lymphocytes from HIV-1 infected patients.

HIV-1 infection induces aberrant ganglioside GM2 expression on infected cell lines, and human IgM anti-GM2 monoclonal antibody (L55 Ab) together with normal fresh human serum (FHS) as a source of complement causes complement mediated cytolysis of HIV-1 infected cells as well as HIV-1 particles. We report here that high expression of GM2 was also detected on HIV-1 infected lymphocytes from HIV-1 seropositive patients. L55 Ab effectively suppressed the generation of HIV in the presence of FHS in primarily cultured lymphocytes from HIV-1 infected patients in ex vivo experiments, and the suppression was enhanced additively by AZT. These data suggest that L55 Ab may increase the therapeutic effect of chemotherapy.

Antibodies, Monoclonal↗
PubMed1999

Regeneration of periodontal tissues by basic fibroblast growth factor.

Several growth factors (or cytokines) have recently received attention because of their ability to actively regulate various cellular functions of periodontal ligament (PDL) cells and the effects of topical application of such factor(s) on periodontal tissue regeneration has been evaluated. In this study, we examined the role of basic fibroblast growth factor (bFGF) in the wound healing and regeneration of periodontal tissues. Alveolar bone defects (such as 2-wall, 3-wall and furcation class II bone defects) were created surgically in beagle dogs and primates. Recombinant bFGF was topically applied to the artificial bony defects. Six or 8 wk after application, the periodontal regeneration was morphologically and histomorphometrically analyzed. In all sites where bFGF was applied, significant periodontal ligament formation with new cementum deposits and new bone formation was observed in amounts greater than in the control sites. We found it noteworthy that no instances of epithelial down growth, ankylosis or root resorption were observed in the bFGF sites. In vitro studies demonstrated that bFGF enhances the proliferative responses of human PDL cells, which express FGF receptor-1 and -2, but inhibits the induction of alkaline phosphatase activity and mineralized nodule formation by PDL cells. Interestingly, we observed that the mRNA level of laminin in PDL cells, which plays an important role in angiogenesis, was specifically upregulated by bFGF stimulation, but that of type I collagen was downregulated. The present study demonstrates that bFGF can be applied as one of the therapeutic modalities which actively induce periodontal tissue regeneration. The results of in vitro studies suggest that by suppressing the cytodifferentiation of PDL cells into mineralized tissue forming cells, bFGF may play important roles in wound healing by promoting angiogenesis and inducing the growth of immature PDL cells, and may in turn accelerate periodontal regeneration.

Administration, Topical↗
PubMed1999

An alpha-L-arabinofuranosidase from Trichoderma reesei containing a noncatalytic xylan-binding domain.

L-Sorbose, an excellent cellulase and xylanase inducer from Trichoderma reesei PC-3-7, also induced alpha-L-arabinofuranosidase (alpha-AF) activity. An alpha-AF induced by L-sorbose was purified to homogeneity, and its molecular mass was revealed to be 35 kDa (AF35), which was not consistent with that of the previously reported alpha-AF. Another species, with a molecular mass of 53 kDa (AF53), which is identical to that of the reported alpha-AF, was obtained by a different purification procedure. Acid treatment of the ammonium sulfate-precipitated fraction at pH 3.0 in the purification steps or pepsin treatment of the purified AF53 reduced the molecular mass to 35 kDa. Both purified enzymes have the same enzymological properties, such as pH and temperature effects on activity and kinetic parameters for p-nitrophenyl-alpha-L-arabinofuranoside (pNPA). Moreover, the N-terminal amino acid sequences of these enzymes were identical with that of the reported alpha-AF. Therefore, it is obvious that AF35 results from the proteolytic cleavage of the C-terminal region of AF53. Although AF35 and AF53 showed the same catalytic constant with pNPA, the former showed drastically reduced specific activity against oat spelt xylan compared to the latter. Furthermore, AF53 was bound to xylan rather than to crystalline cellulose (Avicel), but AF35 could not be bound to any of the glycans. These results suggest that AF53 is a modular glycanase, which consists of an N-terminal catalytic domain and a C-terminal noncatalytic xylan-binding domain.

Amino Acid Sequence↗
PubMed1999

Autoregulatory effect of interleukin-10 on proinflammatory cytokine production by Porphyromonas gingivalis lipopolysaccharide-tolerant human monocytes.

Pretreatment of human peripheral blood monocytes with a very low concentration (0.1 ng/ml) of Porphyromonas gingivalis lipopolysaccharides (LPS) resulted in a significant decrease of interleukin-6 (IL-6) production, but not IL-8 production, by restimulation of a high concentration (1 microg/ml) of the same LPS. In contrast, the same pretreatment with Escherichia coli LPS resulted in the enhanced production of both IL-6 and IL-8 after restimulation. The selective induction by P. gingivalis LPS tolerance of IL-6 production developed in a time-dependent manner during the primary culture. P. gingivalis LPS-pretreated cells were also refractory to a high-dose E. coli LPS restimulation in terms of IL-6 production. The expression of IL-6 mRNA decreased 10 h after restimulation of P. gingivalis LPS-pretreated monocytes. Furthermore, an up-regulation of anti-inflammatory cytokine IL-10 upon a second high-dose LPS rechallenge occurred at the same time point in the pretreated cells. We studied the role of IL-10 in the process of IL-6 down-regulation. Neutralization by an anti-IL-10 polyclonal antibody prevented IL-6 down-regulation in P. gingivalis LPS-pretreated monocytes, whereas IL-8 production was not affected. Addition of exogenous IL-10 during the high-dose LPS stimulation of untreated cells substituted for the LPS pretreatment and resulted in the inhibition of IL-6 production in a dose-dependent manner. A higher dose of IL-10 was required to suppress IL-8 synthesis from monocytes. Our data suggest that IL-10 mediates IL-6 down-regulation in P. gingivalis LPS-tolerant monocytes in an autocrine manner.

Base Sequence↗