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Biomedical subjects

K Okuda

Publications and source records attributed to K Okuda.

At least 469 records · Page 26Linked to original sources
PubMed1993

Flow cytometric analysis of G-CSF receptors on normal white cells and leukemic cells.

In treatment of leukemia with granulocyte colony stimulating factor (G-CSF), the possibility is that G-CSF receptors on leukemic cells lead to activate its proliferation in response to G-CSF. Therefore, it is useful to know the proportions of leukemic cells with receptors for G-CSF. We used flow cytometry to estimate the proportion of such cells and normal granulocytes with G-CSF binding activity. Recombinant human G-CSF was labeled with fluorescein isothiocyanate. Granulocytes showed higher binding to the G-CSF than lymphocytes. Leukemic cells obtained from 17 to 21 patients with AML bound specifically to G-CSF, but leukemic cells with lymphoid malignancies did not. Our results showed positive correlation with date obtained by the isotopic G-CSF receptor assay. With this method, leukemic cells need not be isolated; they can be distinguished from lymphocytes or granulocytes on the cytometry screen. Radioisotopes are not needed. It is judged to be practical for the clinical laboratory.

Flow Cytometry↗
PubMed1993

Strong synergistic effects of multicomponent vaccine for human immunodeficiency virus infection.

Several peptides were synthesized, based on sequences of the HTLV-IIIB, HTLV-IIRF, and HTLV-IIIMN strains. These corresponded to the V3 region, the killer T cell activating site, the constant region of env, gag region protein and the helper T cell activating site. Some of these peptides were coupled to keyhole limpet hemocyanin (KLH), and some of them were polymerized with m-maleimido benzoyl-N hydroxysuccinimide ester (MBS). These peptides were used to immunize rabbits and mice. Antisera from immunized animals showed good levels of inhibition of CD4-dependent cell fusion by in vitro HIV infection. The antisera also inhibited the production of p24 protein in the HIV-infected culture system. Interestingly, a strong synergistic HIV growth inhibition by antiserum was observed when we immunized animals with multicomponent vaccine. In addition, substantial levels of HIV antigen-specific IL-2 producing and interferon-gamma (IFN-gamma) producing cells were also observed in lymph node cells from vaccinated mice. These results suggest that immunization with multicomponent vaccine can induce high levels of humoral antibodies as well as activate HIV-specific cellular immunity.

AIDS Vaccines↗
PubMed1993

[Assessment of myocardial metabolic reserve with positron emission tomography and C-11 acetate].

Positron emission tomography (PET) with C-11 acetate allows noninvasive quantification of myocardial oxidative metabolism. To assess the myocardial metabolic reserve, clearance of C-11 acetate from the myocardium was measured with PET in 8 normal subjects at rest and during the infusion of dobutamine (inotropic agent) or dipyridamole (vasodilator). During dobutamine infusion, the clearance rate constant of C-11 acetate increased significantly (0.063 +/- 0.014 vs 0.109 +/- 0.016, p < 0.002) in good correlation with the rate-pressure product (r = 0.83). During dipyridamole infusion, myocardial acetate clearance also significantly increased (0.088 +/- 0.024, p < 0.05) in correlation with the rate-pressure product (r = 0.54). In normal myocardium, myocardial oxidative metabolism increased in response to increased work load with pharmacological stress. These findings suggest that PET with C-11 acetate and pharmacological stress may be a promising approach for the evaluation of metabolic reserve in patients with ischemic heart disease.

Acetates↗
PubMed1993

Evaluation of proliferating cells in acute leukemia with antibodies to proliferating cell nuclear antigen and Ki-67 monoclonal antibodies.

The percentage of proliferating leukemic cells was evaluated in 32 patients with acute leukemia; this percentage was measured by flow cytometry and immunostaining with antibodies to proliferating cell nuclear antigen and Ki-67 monoclonal antibodies. In the peripheral blood samples, the mean proportion of cells that stained for proliferating cell nuclear antigen was 10%, the mean proportion of cells that stained for Ki-67 was 12%, and the mean proportion of cells in the S phase was 5.9%; in the bone marrow samples, these means were 15%, 15%, and 10.1%, respectively, all of which were higher than in the peripheral blood samples. There was a correlation between the proportion of cells that stained for proliferating cell nuclear antigen and cells that stained for Ki-67, and there was no correlation between the proportion of cells that stained for proliferating cell nuclear antigen or Ki-67 and the proportion of cells in the S phase.

Acute Disease↗
PubMed1993

Electrochemical assay system with single-use electrode strip for measuring lactate in whole blood.

We have developed an assay system for measuring lactate in whole blood, consisting of a single-use strip of an enzyme-coated electrode and a small meter. The electrode strip is made of three plastic films: a cover sheet, a spacer, and an insulation layer printed with electrodes that are coated with lactate oxidase (EC 1.1.3.x) and ferricyanide as an electron mediator. The meter measures the magnitude of the anodic current of the reduced mediator by the enzymatic reaction and displays the lactate concentration 60 s after a blood sample (5 microL) is applied. The calibration curve was linear up to 20 mmol/L, and the between-run CVs at three concentrations were 1.7-8.4%. Lactate concentrations determined by this method (y) in blood samples from healthy individuals before and after exercise agreed with the results obtained by the conventional enzymatic method (x): y = 0.97x - 0.3, Sy/x = 0.7. This assay provides a rapid and convenient test for measuring blood lactate concentrations.

Biosensing Techniques↗
PubMed1993

Impaired immunity in obesity: suppressed but reversible lymphocyte responsiveness.

Although obese people have been reported to have a higher incidence of infections and some types of cancer, the immunocompetence of obese subjects remains poorly understood. To investigate whether obesity affects immunity, we studied obese subjects (BMI > 30 kg/m2) whose health was uncomplicated by any other disorder, including hyperglycemia. We compared mitogen-induced blastogenic response of peripheral blood lymphocytes in 34 obese subjects (mean +/- s.e. BMI: 38.4 +/- 2.0 kg/m2) and 35 non-obese controls (BMI: 21.3 +/- 0.4 kg/m2) who were matched for age and sex. The effects of weight reduction were also evaluated in 19 obese persons (BMI: 36.4 +/- 1.8 kg/m2) on a very low calorie diet. Mean (+/- s.e.) intracellular incorporation of [3H]-thymidine, on stimulation of T lymphocytes with either phytohaemagglutinin (PHA) or concanavalin A (Con A), and B lymphocytes with pokeweed mitogen, was significantly diminished in obese subjects compared to non-obese controls (47552 +/- 6917 vs. 83720 +/- 6252 cpm, P < 0.001; 30301 +/- 6018 vs. 45942 +/- 3723 cpm, P < 0.05; 13669 +/- 2971 vs. 23735 +/- 2048 cpm, P < 0.01, respectively). After weight reduction (BMI: 27.8 +/- 1.2 kg/m2), the mean T lymphocyte responses to PHA and Con A were increased significantly vs. baseline (98404 +/- 2444 vs. 50337 +/- 9516 cpm, P < 0.05 and 69523 +/- 15480 vs. 36695 +/- 8006 cpm, P < 0.05, respectively). Depressed blastogenesis of B lymphocytes was also augmented but was not statistically significant. The results suggest that obese subjects have underlying immune impairment in responsiveness of lymphocytes and that these impairments are reversible with adequate weight reduction.

Adult↗
PubMed1993

[Three-dimensional assessment of myocardial blood flow and glucose metabolism using oblique-angle tomograms and polar map displays of cardiac PET images].

To evaluate clinical value of three-dimensional assessment of cardiac PET image, oblique-angle tomograms and polar map displays were reconstructed from transaxial PET images using 18F-2-fluoro-2-deoxyglucose and 13N-ammonia in 19 patients with coronary artery disease. Short-axis and vertical long-axis images enabled to evaluate extent and severity of perfusion abnormality easily in the anterior and inferior regions which were tangential in the transaxial images. Using polar map displays, perfusion/metabolism mismatch may be more easily assessed. Thus, semiquantitative analysis of ischemic and infarcted myocardium may be permitted with PET studies.

Aged↗
PubMed1993

[Post-transfusional syndrome like graft versus host disease].

We studied clinical and immunological changes of the post-transfusional syndrome like graft versus host disease (GVDH) in six patients after open heart surgery and in one patient after hepatectomy. In the patient with hepatocellular carcinoma, transcatheter arterial embolization had been previously done. All patients received homologous blood transfusion during and after surgery and erythroderma associated hyperthermia occurred approximately 10 days after operation. Patients receiving open heart surgery died on between postoperative 17th and 21st day. One patient with hepatectomy died on the 29th day after operation. Skin biopsies in all patients showed the findings of acute GVHD. The number of CD3+ and CD4+ T lymphocytes decreased at postoperative day 1, however, the number of CD3+ T lymphocyte increased in three patients after postoperative day 14. The postoperative value of interleukin-2 production was low in patients in whom the value was measured. The immunological status in host has not been clearly resolved. However, the postoperative changes of lymphocytes subsets were abnormal and IL-2 production in two patients showed low level. Therefore, it was considered that pre and postoperative measurement of cell-modiated immunity might predict the occurrence of the post-transfusional GVHD and might be one of useful examinations to prevent the disease.

Aged↗
PubMed1993

[Investigation of microwave coagulo-necrotic therapy for 21 patients with small hepatocellular carcinoma less than 5 cm in diameter].

Microwave coagulo-necrotic therapy (MCN) was performed in 21 patients with small hepatocellular carcinoma less than 5cm in diameter and this therapeutic method was determined to be effective from the following results. 1) A marked low density area was seen in the region receiving the therapy and no enhanced findings were observed by enhanced CT one month postoperatively. 2) Recurrence appeared in 5 patients (23.8%) and only one patient died 1 year and 6 months after the operation. However, the other 20 patients survived for a maximum of 3 years and 2 months postoperatively. 3) The levels of total bilirubin and GOT in these patients were similar to those of patients who underwent hepatectomy. However, the levels of prothrombin time and hepaplatin test in patients with MCN changed less than in those who received hepatectomy. 4) Tendency of the renal failure was seen in 2 patients, and the other 19 patients did not have any complication postoperatively.

Aged↗
PubMed1993

[Granisetron oral phase III clinical trial--study on the inhibitory effect of granisetron for nausea/vomiting induced by chemotherapy for tumors in the hematopoietic organs].

The efficacy and safety of oral granisetron against nausea and vomiting induced by chemotherapy for tumors in the hematopoietic organs were investigated. Depending on the day of anticancer drug administration, single administration or 2 to 6-day repeated administration of granisetron at 2 mg once daily was conducted. The clinical efficacy rate against nausea and vomiting was 91.6% on the first day of administration of anti-cancer drugs and 90% or over on and after the second day of administration. Compared with the status at the previous chemotherapy, a significant decrease in vomiting frequency was observed during the present trial. Adverse events which were suspected to be related to granisetron included 1 case of mild feeling of residual urine and another demonstrating very mild eosinophilia. From the above results, it was confirmed that granisetron was a safe and effective antiemetic against nausea and vomiting induced by anticancer drug administration.

Administration, Oral↗
PubMed1993

Interleukin-3 and p210 BCR/ABL activate both unique and overlapping pathways of signal transduction in a factor-dependent myeloid cell line.

Chronic myelogenous leukemia (CML) is characterized by a specific chromosomal translocation occurring between the long arms of chromosomes 9 and 22 resulting in a fusion product, p210 BCR/ABL, which has elevated tyrosine kinase activity. Expression of p210 BCR/ABL in murine interleukin-3 (IL-3)--dependent cell lines typically converts these cell lines to factor-independence by a non-autocrine mechanism. The IL-3 receptor is believed to function in part by activating a receptor-associated tyrosine kinase, leading to the hypothesis that p210 BCR/ABL may induce factor-independence of myeloid cells by constitutively phosphorylating some common signal-transducing proteins that normally would be phosphorylated on tyrosine residues in response to IL-3. p210 BCR/ABL subclones were constructed from an IL-3-dependent murine myeloid cell line, 32Dcl3, by transfection of a plasmid containing a full-length p210 BCR/ABL cDNA. Following transfection, the cells became completely factor-independent within 3 weeks. We examined the effects of p210 BCR/ABL and IL-3 on the pattern of tyrosine phosphorylation of cellular proteins in 32Dcl3 cells using one- and two-dimensional antiphosphotyrosine immunoblotting. WEHI-3B conditioned media (WEHI-CM) was used as a source of IL-3. The introduction of p210 BCR/ABL results in constitutively increased levels of tyrosine phosphorylation of more than 20 new proteins, while WEHI-CM induced transient tyrosine phosphorylation of 6 to 10 new proteins. Using two-dimensional immunoblots to examine phosphoproteins, four categories could be identified: (1) proteins that are inducibly tyrosine phosphorylated in response to WEHI-CM in 32Dcl3 cells only, (2) proteins inducibly tyrosine phosphorylated by WEHI-CM only in p210 BCR/ABL+ cells, (3) proteins that are inducibly tyrosine phosphorylated in response to WEHI-CM in both 32Dcl3 cells and p210 BCR/ABL+ cells, and (4) proteins inducibly tyrosine phosphorylated in response to WEHI-CM and constitutively phosphorylated in the presence of p210 BCR/ABL. We have identified one of the proteins in category 4 as p42 mitogen-activated protein (MAP) kinase (ERK2). Overall, however, we found that the signal transduction pathways of IL-3 and BCR/ABL are strikingly different, suggesting that most of the immediate substrates of the IL-3 receptor-activated tyrosine kinase and p210 BCR/ABL kinase are different. Convergence of signaling pathways at p42 MAP kinase is of interest since activation of this kinase has been linked to mitogenesis in many systems. Identification of the overlapping proteins of both IL-3 signal transduction in 32Dcl3 cells and p210 BCR/ABL+ cells may help explain the growth-promoting effects of this oncogene.

Animals↗
PubMed1993

[Fat soluble vitamins].

The first part of this presentation discusses the history of the discovery of vitamins that dates back to the early 20th century. The latter part deals with the basic physical and biochemical functions of fat-soluble vitamins, namely, vitamin A, vitamin D, vitamin E and vitamin K. Unlike water-soluble vitamins, most of which act as a coenzyme binding to an apoenzyme for the formation of holoenzyme, fat soluble vitamins have individual biochemical functions that do not share the same mechanism. Although studies on the mechanism of fat-soluble vitamin function in the cell were hampered due to difficulty in solubilization for in vitro studies in the past, recent progress in the understanding of such mechanisms has been remarkable.

Animals↗
PubMed1993

Non-specific immunological abnormalities and association of autoimmune diseases in idiopathic portal hypertension. A study by questionnaire.

A large survey by questionnaire of idiopathic portal hypertension (IPH) in Japan disclosed that 11.9% of 160 cases were associated with one or two autoimmune diseases, and 26.3% of them disclosed hypergammaglobulinemia. Patients with IPH also frequently showed one or more autoantibodies in the serum, such as antinuclear or anti-smooth muscle antibodies. These findings overlapped frequently in the same patient. These data imply that immunological disturbance and/or chronic antigenic stimulation are related to the pathogenesis of IPH, though the exact immunological mechanisms remain unclear. It will be necessary to study more specific immunological reactions in IPH.

Autoantibodies↗
PubMed1993

Disinfectant effects of "Taisalite" and "Taifresh Ace" containing Irgasan DP300 against MRSA and HIV.

Sterilization and disinfection in dental clinics and laboratories are important in controlling disease vectors such as methicillin-resistant Staphylococcus aureus (MRSA) and human immunodeficiency virus (HIV). We determined the inactivation of disinfectant effects of "Taisalite" and "Taifresh Ace" containing Irgasan DP300 on MRSA, Streptococcus pyogenes, Candida albicans, and HIV. Exposure for 10 seconds to 50% or 5% Taisalite solution inactivated HIV completely. HIV was also completely inactivated by 10 minutes of exposure to 50% or 5% of Taifresh Ace solution. Taisalite possessed strong bactericidal activity against S. pyogenes and MRSA. C. albicans was resistant to 10 to 30 second exposures to Taisalite. MRSA and C. albicans were killed completely by exposure to 90% Taifresh Ace solution for 10 minutes. S. pyogenes was not highly sensitive to Taifresh Ace. The present study showed that Irgasan DP300 containing Taisalite is an excellent disinfectant against HIV and MRSA and that Taifresh Ace is a useful detergent against these micro-organisms.

Anti-Infective Agents, Local↗
PubMed1992

Purification and characterization of 7 alpha-hydroxy-4-cholesten-3-one 12 alpha-hydroxylase.

The isoform of cytochrome P450 that catalyzes the 12 alpha-hydroxylation of 7 alpha-hydroxy-4-cholesten-3-one, an intermediate in the conversion of cholesterol to cholic acid, was purified to homogeneity from rabbit liver microsomes. The extent of purification in the various steps was judged by an assay involving high performance liquid chromatography. The purified enzyme showed a single band on SDS-polyacrylamide gel electrophoresis (M(r) = 50,000). The NH2-terminal amino acid sequence is as follows: Val-Leu-Trp-Gly-Leu-Leu-Gly-Ala-Leu-Leu-Met-Val-Met-Val-Gly-, which is different from that of any other P450s so far reported. The specific content of the enzyme was 13.3 nmol of cytochrome P450/mg of protein. Upon reconstitution with NADPH-cytochrome P450 reductase and cytochrome b5, the P450 enzyme showed a high activity of 12 alpha-hydroxylation with a turnover number of 36.6 min-1 at 37 degrees C. The omission of either cytochrome P450 or NADPH-cytochrome P450 reductase resulted in complete loss of activity, and the omission of cytochrome b5 resulted in 40% loss of activity. Antibodies prepared from mouse inhibited the 12 alpha-hydroxylase activity of rabbit liver microsomes about 90% and that of the rat liver microsomes 50%. The enzyme activity was not inhibited by other antibodies raised against other forms of P450 that catalyze different monooxygenation reactions toward xenobiotics or endogenous substrates. Anti-cytochrome b5 antibody inhibited the activity 40%, suggesting the functional role of this protein, and anti-reductase inhibited the activity almost completely. The microsomal enzyme activity was markedly elevated by starvation or streptozotocin administration to the animals. However, an immunoblotting experiment showed no correlation between the enzyme activity and the amount of protein, suggesting that post-translational modification may occur.

Amino Acid Sequence↗
PubMed1992

Parathyroid hormone inhibits 25-hydroxyvitamin D3-24-hydroxylase mRNA expression stimulated by 1 alpha,25-dihydroxyvitamin D3 in rat kidney but not in intestine.

Using a cDNA probe for rat renal 24-hydroxylase, expression of its mRNA was compared in the rat kidney and intestine. Vitamin D-deficient rats received a single injection of 1 alpha,25-dihydroxyvitamin D3. Expression of 24-hydroxylase mRNA was first detected in the kidney at 3-h post-injection and increased thereafter. Similarly, 24-hydroxylase mRNA was expressed in the intestine after 1 alpha,25-dihydroxyvitamin D3 injection. However, the dose level of 1 alpha,25-dihydroxyvitamin D3 required to induce the intestinal 24-hydroxylase mRNA expression was only 1/100 the amount required to induce renal 24-hydroxylase mRNA. Induction of intestinal 24-hydroxylase mRNA expression by 1 alpha,25-dihydroxyvitamin D3 was far more rapid than that of renal 24-hydroxylase mRNA. Thyroparathyroidectomy shortened the time required to induce expression of renal, but not intestinal, 24-hydroxylase mRNA. Administration of either parathyroid hormone or cAMP to vitamin D-deficient rats greatly reduced the expression of 24-hydroxylase mRNA in the kidney but not in the intestine. When rats were fed a vitamin D-repleted diet containing 0.7% (adequate) or 0.03% (low) calcium for 2 weeks, intestinal expression of 24-hydroxylase mRNA could be induced only in the low calcium group. In contrast, renal mRNA expression was preferentially stimulated in the adequate calcium group. These results clearly demonstrate that the expression of 24-hydroxylase mRNA is down-regulated by parathyroid hormone in the kidney but not in the intestine.

Animals↗