Biomedical subjects

H Okada

Publications and source records attributed to H Okada.

At least 667 records · Page 37Linked to original sources

PubMed1993

[Relationship among aromatase activity, estrogen receptor and progesterone receptor in ovarian tumors from postmenopausal women].

Aromatase activity, as well as steroid receptors, has been demonstrated in ovarian tumors. Aromatase activity was detected in 35 tumors (81%), PR in 21 tumors (49%) and ER in 13 tumors (30%) out of 43 ovarian tumors (27 benign, 14 malignant and 2 granulosa cell tumors). Moreover, immunohistochemical study demonstrated aromatase cytochrome P-450 (P-450arom) in the tumor tissues. Aromatase activity was significantly greater in PR-positive tumors than in PR-negative tumors (p < 0.002). There was a positive correlation between aromatase activity and the PR level (rs = 0.490, p < 0.001). Thirteen of 14 (93%) malignant tumors showed negative PR with low aromatase activity. However, the presence of ER was not correlated with aromatase activity or the presence of PR. There was a positive correlation among serum levels of estradiol, estrone, androstenedione and testosterone, whereas the serum steroid levels were not correlated with aromatase activity, the PR or ER of ovarian tumors. These results suggest that aromatase activity is correlated with PR in ovarian tumors of postmenopausal women.

Adult↗

PubMed1993

Production and characterization of monoclonal antibodies against bacterial lectin of Eikenella corrodens.

A lectin-like substance (EcLS) was purified from the Eikenella corrodens 1073 cell and monoclonal antibodies were produced against it to confirm the role of EcLS in adhesive properties of E. corrodens such as hemagglutination and coaggregation with oral bacteria. Four hybridoma clones were selected. Two of the antibodies were of the IgG1 isotype and the others were of the IgG2b isotype. These monoclonal antibodies inhibited both the hemagglutination of E. corrodens and the coaggregation with Actinomyces viscosus or Streptococcus sanguis. The reactivity of the monoclonal antibody to E. corrodens 1073 was significantly higher than that to E. corrodens 1080 of which adhesive activity was weaker than that of E. corrodens 1073. These findings suggest the difference in adhesive properties is due to the difference in the amount of EcLS expressed on the cell surface. The immunoelectron microscopic study revealed that EcLS of E. corrodens 1073 was localized in the outer space of outer membrane, not in cell surface appendages such as fimbriae where bacteria possessed adhesin. These results suggest that coaggregation of E. corrodens with A. viscosus or S. sanguis was mediated by EcLS.

Antibodies, Monoclonal↗

PubMed1993

[Clinical application of a third generation lithotripter (Therasonic) for upper urinary tract calculi].

A third generation lithotripter (THERASONIC Lithotripsy Treatment System) was used for disintegration of upper urinary tract calculi. A total of 115 patients was treated at Miki Municipal Hospital, 54 with renal calculi, 8 with UPJ calculi, 30 with upper and 23 with lower ureter calculi. The stone-free rate one month after treatment was 89%, 88%, 90% and 100% for renal, UPJ, upper ureter and lower ureter calculi, respectively. As for side effects, we experienced two cases of perinephric hematoma which were treated conservatively. However, we encountered no other severe complications. These findings clearly indicated that the THERASONIC lithotripter is highly useful for disintegration of calculi of the upper urinary tract.

Adolescent↗

PubMed1993

[Lymphocyte subpopulations in maintenance hemodialysis patients receiving recombinant human erythropoietin].

The effect of recombinant human erythropoietin (rHuEPO) on the lymphocyte subpopulations of maintenance hemodialysis patients has been studied. Peripheral lymphocyte counts, lymphocyte subpopulations (Two color analysis) and PHA-induced proliferative response were measured before and after rHuEPO administration during 8 months in 22 stable hemodialysis patients (mean age 52 years, mean duration of dialysis 48 months). We could find a significant increase in the proportions of CD4+ Leu8- cells, HLA-DR+ cells, CD8+ HLA-DR+ cells, CD14+ HLA-DR+ cells and CD4+ Leu8-/CD8+ CD11b+ cells ratios after rHuEPO therapy. In addition, a significant decrease in the proportions of CD16+ CD57- cells and CD20+ cells could be found after rHuEPO therapy. These results suggest that rHuEPO administration to stable hemodialysis patients induces increases in lymphocytes categorized into helper subset groups and in activated T lymphocytes.

Adult↗

PubMed1993

[Experimental and clinical studies of temafloxacin in the field of obstetrics and gynecology].

Temafloxacin (TMFX, TA-167) is a new quinolone antimicrobial agent that has a broad antibacterial spectrum against Gram-positive, Gram-negative and anaerobic bacteria. We obtained the following results from laboratory and clinical studies on TMFX. 1. TMFX showed good penetration into the female genital organs and Cmax's in various organs were 2.77-4.24 micrograms/g when 300 mg was administered, and these values were equal to or higher than Cmax in vein blood. 2. The clinical efficacy rate was 95.4% in a clinical study involving 219 cases. The bacterial eradication rate was 96.4% in 139 cases. 3. Nine cases of side effects and 1 case of abnormal change in laboratory findings were noted in 254 cases involved, but none of them was serious. Based on these findings, TMFX is expected to be a useful antimicrobial agent for the treatment of obstetric and gynecological infections.

Administration, Oral↗

PubMed1993

Very late antigen integrins are involved in the adhesive interaction of lymphoid cells to human gingival fibroblasts.

To date, it is still unclear how the trafficking and retention of activated lymphocytes in periodontal lesions are regulated. In this study, we investigated the molecular basis for the adhesive interactions between lymphocytes and human gingival fibroblasts (HGF). Peripheral blood T lymphocytes (PBT) exhibited binding ability, but only when the calls were activated with phorbol 12-myristate 13-acetate (PMA). Among several human cell lines tested, PMA-stimulated Molt-4, a human T-cell leukaemia line, also displayed significant binding ability to HGF. In order to clarify the molecule(s) involved in this cell-cell interaction, a panel of monoclonal antibodies (mAb) was prepared to PMA-activated Molt-4 and one clone, 4-145, was selected on the basis of its ability to block the binding of PMA-activated Molt-4 to HGF. Moreover, 4-145 inhibited the binding of not only activated Molt-4 but also activated PBT and other cell types to HGF. Biochemical and flow cytometric analyses revealed that 4-145 probably recognizes the beta 1 chain of very late antigen (VLA) integrins. Blocking experiments using mAb specific for the alpha-chain of VLA integrins demonstrated the involvement of alpha 4 (VLA-4) and, to a lesser extent, alpha 5 (VLA-5) chains in the adhesive interactions between T cells and HGF. Despite the significant involvement of VLA integrins in the adhesive interaction between PBT and HGF, the binding of PBT to human dermal fibroblasts (HDF) was not abrogated by 4-145, suggesting that HGF and HDF differ in their requirement of VLA integrins for adhesion to activated PBT. Furthermore, the fact that vascular cell adhesion molecule-1 (VCAM-1), one of the ligands of VLA-4, was not detected on HGF by flow cytometry and anti-fibronectin (FN) Ab did not block the adhesive interaction to HGF suggests that not-yet-identified ligand(s) for VLA-4 might be present on HGF.

Cell Adhesion↗

PubMed1993

[Pharmacokinetic and clinical studies on DQ-2556 in the gynecological field].

Pharmacokinetic and clinical studies on DQ-2556, a new cephem antibiotic, in obstetrics and gynecology were performed and following results were obtained. Concentrations of DQ-2556 were determined in serum, internal genital organs and retroperitoneal exudate after single intravenous administration (i.v.) or drip infusion (d.i.v.) of 1.0 g. Serum levels following i.v. were approximately 30 micrograms/ml at 1 hour, 14 micrograms/ml at 3 hours 30 minutes, and concentrations in internal genital organs including oviduct, ovary, endometrium, myometrium, cervix uteri and portio vaginalis reached approximately 50% to 70% levels of serum concentration. The mean concentration (n = 6) in the retroperitoneal exudate after d.i.v. of 1.0 g following radical hysterectomy were about 20 micrograms/ml, 23 micrograms/ml, 14 micrograms/ml and 8 micrograms/ml at 1 hour, 2 hours 30 minutes, 4 hours 30 minutes and 6 hours 30 minutes, respectively. In clinical trials, DQ-2556 (2.0 g b.i.d. for daily dose) was given in 5 patients with gynecological infections such as pyometra (1 case), salpingitis (1), retroperitoneal space infection (2), pelvic peritonitis (1). The clinical results were evaluated as good in 3 cases and poor in 2 cases including a case with salpingitis infected by Pseudomonas aeruginosa and the other with pelvic peritonitis caused by Methicillin-resistant Staphylococcus aureus. Bacteriologically, 11 organisms were isolated from patients, and eradication rate was 54.5%. Neither side effect nor abnormal laboratory test result was observed. Thus, DQ-2556 appears to be effective for gynecological infections, and the good results were supported by good penetration of the compound into tissues of internal genital organs and retroperitoneal exudate after i.v. or d.i.v.

Adult↗

PubMed1993

[Surgical treatment of ventricular septal defect associated with Down syndrome].

Twelve patients with ventricular septal defect with Down syndrome (Down group) underwent cardiac surgery. As they had pulmonary hypertension (Pp/Ps > or = 0.5), we chose twenty patients who had pulmonary hypertension (Pp/Ps > or = 0.5) with ventricular septal defect without Down syndrome as control group. After cardiac surgery, Pp/Ps in Down group decreased significantly from 0.81 +/- 0.14 to 0.48 +/- 0.25 (p < 0.01). Cardiac index (l/min/m2) between 24 hours after operation was 3.3-3.8 in Down and 4.1-4.8 in control group (NS). Oxygenation index (mmHg) between 24 hours after operation was 211-266 in Down and 230-314 in control group (NS). Eleven out of 12 patients in Down group had good operative result. One patient was complicated with post-operative pulmonary hypertensive crisis. Low output syndrome and death were not encountered in Down group. We were satisfied with operative results and encourage surgical treatment for ventricular septal defect with Down syndrome.

Child↗

PubMed1993

[Clinical analysis of the factors affecting the prognosis of acute renal failure].

Analysis of the factors influencing the prognosis of acute renal failure was carried out in cases experienced during the past 10 years. The factors presumed directly affecting the renal function (acute insults) and coexistent predisposing factors (risk factors) were analysed. The followings were considered to be acute insults: surgery/trauma/burn, drug intoxication, sepsis, hypotension, dehydration, rhabdomyolysis, hepatorenal syndrome, and hypercalcemia/hyperuricemia. Suspected risk factors included age, urine volume, underlying disorders/complications. Risk factors rather than acute insults were related to the outcome of acute renal failure. The mortality rate increased as the associated risk factors increase in number. In non-oliguric cases, maximum serum creatinine level was lower than the anuric cases, however there was no difference in the duration of the impaired renal function between 2 groups. In survival cases, the factors affecting the time for the recovery of renal function were also studied, but no definite factors could be determined.

Acute Kidney Injury↗

PubMed1992

Modulation of transient type K channel cloned from rat heart.

We have cloned a transient type K channel from rat heart (RH10) and coexpressed a metabotropic glutamate receptor (mGluR5) to study the functional modulation of RH10 coupled to the phosphatidylinositol (PI) hydrolysis. Stimulation of mGluR5 suppressed peak amplitude of RH10 current and affected voltage dependence of activation and inactivation of the channel.

Animals↗

PubMed1992

Site-directed mutagenesis at aspartate and glutamate residues of xylanase from Bacillus pumilus.

To elucidate the reaction mechanism of xylanase, the identification of amino acids essential for its catalysis is of importance. Studies have indicated the possibility that the reaction mechanism of xylanase is similar to that of hen's egg lysozyme, which involves acidic amino acid residues. On the basis of this assumption, together with the three-dimensional structure of Bacillus pumilus xylanase and its amino acid sequence similarity to other xylanases of different origins, three acidic amino acids, namely Asp-21, Glu-93 and Glu-182, were selected for site-directed mutagenesis. The Asp residue was altered to either Ser or Glu, and the Glu residues to Ser or Asp. The purified mutant xylanases D21E, D21S, E93D, E93S, E182D and E182S showed single protein bands of about 26 kDa on SDS/PAGE. C.d. spectra of these mutant enzymes show no effect on the secondary structure of xylanase, except that of D21E, which shows a little variation. Furthermore, mutations of Glu-93 and Glu-182 resulted in a drastic decrease in the specific activity of xylanase as compared with mutation of Asp-21. On the basis of these results we propose that Glu-93 and Glu-182 are the best candidates for the essential catalytic residues of xylanase.

Aspartic Acid↗

PubMed1992

CD48 is a counter-receptor for mouse CD2 and is involved in T cell activation.

CD2 is an intercellular adhesion molecule that has been implicated in T cell activation and differentiation both in humans and mice. Although the ligand for human CD2 has been defined as LFA-3, that for murine CD2 has not been identified yet. To identify the ligand for mouse CD2, we generated a chimeric molecule consisting of the extracellular domain of mouse CD2 and human immunoglobulin (Ig)G1 Fc (mCD2Rg). A hamster monoclonal antibody (mAb), HM48-1, was established by screening mAbs that could block the binding of mCD2Rg to T cell lines at the ligand site. The putative mouse CD2 ligand recognized by this mAb was a glycosyl phosphatidylinositol-anchored glycoprotein with an apparent molecular mass of 45 kD, which were shared characteristics with human LFA-3. However, its expression was predominantly restricted to hematopoietic cells, unlike human LFA-3. Protein microsequencing analysis for the NH2-terminal 18 amino acid residues of the affinity-purified HM48-1 antigen revealed that it is almost identical with mouse CD48. This identity was further confirmed by the reactivity of HM48-1 with a soluble recombinant CD48 (sCD48) protein and the molecule recognized by a rat mAb raised against sCD48. A rat anti-CD48 mAb blocked the mCD2Rg binding as well as HM48-1. Moreover, sCD48 also inhibited the mCD2Rg binding to the cellular ligand. Finally, like anti-CD2 mAb, HM48-1 inhibited the phytohemagglutinin response and, when crosslinked, augmented the anti-CD3 response of splenic T cells. These results indicate that CD48 is a ligand for mouse CD2 and is involved in regulating T cell activation.

Animals↗

PubMed1992

Properties of aspartate racemase, a pyridoxal 5'-phosphate-independent amino acid racemase.

Aspartate racemase from Streptococcus thermophilus contains no pyridoxal 5'-phosphate or other cofactors such as FAD, NAD+, and metal ions. It was affected by neither carbonyl reagents such as hydroxylamine nor sodium borohydride but was strongly inhibited by iodoacetamide and other thiol reagents. Aspartate, cysteate, and cysteine sulfinate were the only substrates. The Km values for L- and D-aspartate were 35 and 8.7 mM, respectively. The enzyme catalyzed the exchange of alpha-hydrogen of the substrate with the solvent hydrogen. Racemization of L-aspartate in 2H2O showed an overshooting in the optical rotation of aspartate before the substrate was fully racemized. This shows that the removal of alpha-hydrogen of the substrate is at least partially rate-determining. When L- or D-aspartate was incubated with aspartate racemase in tritiated water, tritium was incorporated preferentially into the product enantiomer. The results strongly suggest that aspartate racemase contains two hydrogen acceptors.

Amino Acid Isomerases↗

PubMed1992

A new biological activity of the complement factor H: identification of the precursor of the major macrophage-chemotactic factor in delayed hypersensitivity reaction sites of guinea pigs.

The guinea pig complement factor H(FH) and the plasma precursor(PMCFS-1) of the major monocyte-chemotactic factor(MCFS-1) found in the skin site of delayed hypersensitivity reaction(DHR) induced in the guinea pigs were compared in the antigenicity and the function. Both anti-FH-IgG and anti-MCFS-1-IgG formed a single precipitation line against FH, PMCFS-1, MCFS-1 and guinea pig plasma, and these lines fused one another without any spur formation. The inhibition activity of FH for C3bBb was absorbed by anti-MCFS-1-F(ab')2 in a dose-dependent manner. PMCFS-1 inhibited C3bBb activity dose-dependently as FH. These results show that FH is identical to PMCFS-1 and imply that FH, converted to MCFS-1 plays as a monocyte-chemotactic factor in the site of DHR.

Animals↗

PubMed1992

No stop codons in the antisense strands of the genes for nylon oligomer degradation.

Genes for nylon oligomer-degrading enzymes are unique in the sense that the enzymes encoded by them are found not to have any appropriate substrates during most of the period of their evolution. Furthermore, these nylB genes form a family not related to any other known gene families. The base sequences of these genes were examined and a common characteristic was found: a long stretch of sequence without chain-terminating base triplets, defined as a nonstop frame (NSF), is being maintained on the antisense strand. Moreover, a certain coding frame is open for both the sense and the antisense sequences, while the other frames have many stop codons. The probability of the presence of these NSFs on the antisense strand of a gene is very small (0.0001-0.0018). In addition, another gene for nylon oligomer degradation was found to have a NSF on its antisense strand, and this gene is phylogenically independent of the nylB genes. Therefore, the presence of these NSFs is very rare and improbable. Even if the common ancestral gene of the nylB family was originally endowed with a NSF on its antisense strand, the probability of this original NSF persisting in one of its descendants of today is only 0.007. Unless an unknown force was maintaining the NSF, it would have quickly disappeared by random emergences of chain terminators. Therefore, the presence of such rare NSFs on all three antisense strands of the nylB gene family suggests that there is some special mechanism for protecting these NSFs from mutations that generate the stop codons. Such a mechanism may enable NSFs to evolve into new functional genes and hence seems to be a basic mechanism for the birth of new enzymes.

Amidohydrolases↗

PubMed1992

Specific cytolysis of HIV-infected cells by lymphocytes armed with bifunctional antibodies.

The Fab' fragment of a monoclonal antibody (mAb) directed to CD3 (a portion of the T cell receptor) and the Fab' or F(ab')2 fragment of an mAb to HIV were combined to generate bifunctional antibody (BFA) consisting of antiCD3-Fab' conjugated with anti-HIV-Fab' (Fab'/Fab') or antiCD3-Fab' conjugated with anti-HIV-F(ab')2 (Fab'/F(ab')2), respectively. In the presence of these BFA, HIV-infected target cells were cytolysed by peripheral blood lymphocytes. Treatment of lymphocytes with Fab'/F(ab')2 type BFA rendered the lymphocytes significantly cytotoxic to HIV-infected target cells. Since BFA-armed lymphocytes can react on HIV-infected cells regardless of histocompatibility, lymphocytes from healthy donors could be armed with BFA for treatment of HIV-infected patients including those who do not exhibit histocompatibility with the lymphocyte donor.

Antibodies, Monoclonal↗

PubMed1992

Preparation and kinetic properties of 5-ethylphenazine-lactate-dehydrogenase-NAD+ conjugate, a semisynthetic lactate oxidase showing a hide-and-seek effect.

5-Ethylphenazine-lactate-dehydrogenase-NAD+ conjugate (EP(+)-LDH-NAD+) was prepared by linking poly(ethylene glycol)-bound 5-ethylphenazine and poly(ethylene glycol)-bound NAD+ to lactate dehydrogenase. The average number of the ethylphenazine moieties bound per molecule of enzyme subunit was 0.46, and that of the NAD+ moieties was 0.32. This conjugate is a semisynthetic enzyme having lactate oxidase activity using oxygen or 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) as an electron acceptor; to make such conjugates seems to be a general method for artificially converting a dehydrogenase into an oxidase. When the concentration of oxygen or MTT is varied, the oxidase activity fits the Michaelis-Menten equation with the following kinetic constants: for the reaction system with oxygen, the turnover number per subunit is 2.3 min-1 and Km for oxygen is 1.91 mM; and for the system with MTT, the turnover number is 0.25 min-1 and Km for MTT is 0.076 mM. At the initial steady state of the oxidase reaction, only 2.1% of the NAD+ moieties of the conjugate are in the free state (i.e. not bound in the coenzyme-binding site of the lactate dehydrogenase moiety) and the rest are hidden in the coenzyme site; almost all the NAD+ moieties are in the reduced state. The apparent intramolecular rate constant for the reaction between a free NADH moiety and an oxidized ethylphenazine moiety is 2.3 s-1 and 2.1 s-1 for the systems with oxygen and with MTT, respectively. The apparent effective concentration of the free NADH moiety for the ethylphenazine moiety is 5.5 microM and is much smaller than that (0.34 mM) of the ethylphenazine moiety for the free NADH moiety; this difference is due to the effect of hiding the NADH moiety in the binding site, as the hidden NADH moiety cannot react with the ethylphenazine moiety.

Animals↗

PubMed1992

Principles for designing enzyme-like catalysts based on the rate-acceleration mechanisms of semisynthetic oxidases.

Combinations of substrate-binding sites and catalytic groups constitute various kinds of enzyme-like catalysts. The design of such catalysts can be evaluated by the enhancement of the overall catalytic activity by combining these parts into one catalyst. For a catalyst having one substrate-binding site and one catalytic group, an equation was obtained which shows the relationship between the rate-acceleration due to the combination, the affinity of the site (1/Kd), intrinsic effective concentration (kin/kex) and substrate concentration ([S]). The intrinsic effective concentration is the ratio of the first-order rate constant (kin) of the intramolecular reaction between the catalytic group and the bound substrate and the second-order rate constant (kex) of the intermolecular reaction between the catalytic group and the free substrate; the value depends on the method of linking the catalytic group and the binding site. This equation provides the following principles for designing catalysts of this type with a considerable grade of rate-acceleration: [S] less than or equal to kin/kex and (1/10)[S] less than or equal to Kd less than or equal to kin/kex. To increase kin/kex, the structure of the binding site is required not to reduce the reactivity of the bound substrate, and the linker connecting the binding site and the catalytic group is required to be flexible and to have an appropriate length. A subunit structure is also found to be effective to improve the catalytic activity: the activity of an n-mer is at most n2 times as high as that of the monomer. As for the substrate-binding sites, the sites of natural enzymes and antibodies are good candidates because various kinds of binding sites with high affinity and specificity to the corresponding substrates are available. In addition, the equation relating the rate-acceleration with Kd, kin/kex, and [S] is used for explaining the catalytic efficiency of enzymes energetically. The principle for designing a multifunctional catalyst having several kinds of binding sites for its substrates and intermediates and several kinds of catalytic groups was then investigated. In this case, the diffusion of the intermediates strongly affects the activity of the multifunctional catalyst, and such a diffusion process was also analyzed. On the basis of these analyses, the following principles were obtained.(ABSTRACT TRUNCATED AT 400 WORDS)

Catalysis↗