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Biomedical subjects

K Ohkawa

Publications and source records attributed to K Ohkawa.

At least 109 records · Page 6Linked to original sources
PubMed1991

The facilitated effect of retinol on rat hepatocarcinogenesis induced by 3'-methyl-4-dimethylaminoazobenzene.

To examine the influence of retinol acetate (retinol, known as an inhibitor of tumor promotion) on 3'-methyl-4-dimethyl-aminoazobenzene (3'MeDAB)-induced hepatocarcinogenesis, rats were fed with a diet containing 0.06% 3'MeDAB for 4 or 7 weeks and then with a normal diet for 21 or 18 weeks. Rats were given retinol (0, 6.25, 12.5 and 25.0 mg/rat, dissolved in DMSO) i.p. every 5 days from the 10th week to the 20th week. As a control, rats were fed a basal diet and given retinol at the same doses as mentioned above. At the 25th week, the incidence of hepatoma (hepatocellular carcinoma and cholangiocarcinoma) of each group was checked. In rats fed diet containing 3'MeDAB for 7 weeks, significant increases in the incidence of hepatoma were seen in retinol-treated groups at various doses. In rats fed 3'MeDAB diet for 4 weeks, all three doses also moderately, though not significantly, increased the incidence of hepatoma. No liver tumor was found in rats fed normal diet followed by treatment with retinol at any dose. Except for slight but detectable elevation of cellular retinoic acid binding protein levels in tumor tissues obtained from rats treated with retinol, no obvious differences in cellular retinol binding protein and gamma-glutamyl transpeptidase in the tumor tissues were observed between retinol-treated and untreated rats. Phytohemagglutinin-induced lymphocyte blastogenesis of the tumor-bearing rats with or without retinol treatment showed approximately 50% inhibition compared with that of rats fed normal diet without retinol treatment. These results indicated that the administration of retinol in the early stages of hepatocarcinogenesis enhanced the tumor induction, possibly due to the fixation of malignant transformation of the cells.

Animals↗
PubMed1991

Production of 13 plasma proteins by human testicular yolk sac tumor transplanted into nude mice.

Thirteen human proteins were found in plasma and cystic fluid of mice bearing human testicular yolk sac tumor. Six of them, alpha-fetoprotein, prealbumin, albumin, alpha 1-antitrypsin, hemopexin and transferrin, had been previously demonstrated to be produced by yolk sac tumors. The syntheses of the remaining seven, namely apolipoprotein A1, retinol-binding protein, alpha 2HS-glycoprotein, haptoglobin, apolipoprotein B, C5 component and anti-hemophilic factor, have been demonstrated for the first time.

Adult↗
PubMed1990

Clear cell carcinoma of the human ovary synthesizes and secretes a transferrin with microheterogeneity of lectin affinity.

Human ovarian clear cell carcinoma cell line (transferrin (Tf)-non-producer), HAC 2, cells were adapted to grow in chemically defined synthetic medium when the cells were cultured with medium containing 10 micrograms/ml of insulin at least for 6 months. They synthesized and secreted constantly the 80 kDa protein immunologically similar to human serum Tf (15 +/- 12 ng/ml/10(7) cells/3 days). By sensitive lectin-affinity electrophoresis followed by antibody-affinity blotting technique, a concanavalin A weakly bound or unbound, lentil lectin, a strongly reactive abnormal band, which was rarely found in human serum Tf, was detectable in the Tf synthesized by HAC 2 cells (HACTf). These findings suggest that the HACTf may act as one of the autocrine growth factors and that this heterogeneity of HACTf for lectin affinity is ascribed to differences in the carbohydrate moiety of the Tf.

Adenocarcinoma↗
PubMed1990

Purification and characterization of a rat brain aldehyde dehydrogenase able to metabolize gamma-aminobutyraldehyde to gamma-aminobutyric acid.

An enzyme which catalyses dehydrogenation of gamma-aminobutyraldehyde (ABAL) to gamma-aminobutyric acid (GABA) was purified to homogeneity from rat brain tissues by using DEAE-cellulose and affinity chromatography on 5'-AMP-Sepharose, phosphocellulose and Blue Agarose, followed by gel filtration. Such an enzyme was first purified from mammalian brain tissues, and was identified as an isoenzyme of aldehyde dehydrogenase. It has an Mr of 210,000 determined by polyacrylamide-gradient-gel electrophoresis, and appeared to be composed of subunits of Mr 50,000. The close similarity of substrate specificity toward acetaldehyde, propionaldehyde and glycolaldehyde between the enzyme and other aldehyde dehydrogenases previously reported was observed. But substrate specificity of the enzyme toward ABAL was higher than those of aldehyde dehydrogenases from human liver (E1 and E2), and was lower than those of ABAL dehydrogenases from human liver (E3), Escherichia coli and Pseudomonas species. The Mr and relative amino acid composition of the enzyme are also similar to those of E1 and E2. The existence of this enzyme in mammalian brain seems to be related to a glutamate decarboxylase-independent pathway (alternative pathway) for GABA synthesis from putrescine.

Aldehyde Dehydrogenase↗
PubMed1989

Overcoming effect of antibody against rat alpha-fetoprotein (AFP) on the growth of daunorubicin-resistant mutant rat ascites hepatoma cell line AH66.

A daunorubicin (DNR)-resistant variant (AH66DR) of alpha-fetoprotein (AFP)-producing rat ascites hepatoma AH66 was established. AH66DR was 169 times more resistant to DNR than AH66. A growth-inhibitory effect due to the decrease in sugar uptake following treatment of the cell lines with specific antibody against highly purified rat AFP was also observed. Pre-incubation of both lines with antibody prior to the measurement of 2-deoxy-D-glucose (2dG) uptake resulted in a 45-55% decrease in 2dG uptake compared to control cells with a 2-fold reduction of Vmax value while the Km remained unchanged. Upon pre-incubating AH66DR with antibody, an increased intracellular level of DNR concentration with reduction of efflux rate was observed. A significantly superior cytotoxic effect against AH66DR, which reached almost the same level as the cytotoxic effect of DNR against AH66, was found, as compared to various other controls when tumor cells were cultured with a mixture of antibody and DNR. Our in vitro results suggest that the DNR-resistance of the AFP-producing tumor cells may be overcome if the cells are treated with specific antibody.

Animals↗
PubMed1989

Serum levels and biochemical characteristics of human ovarian carcinoma-associated antigen defined by murine monoclonal antibody, CF511.

The murine monoclonal antibody (Mab) against human common epithelial ovarian carcinoma, CF511, was generated by immunising mice with human fetal tissue extract from early first trimester, followed by booster injection of an ovarian cancer cell line. Mab CF511 recognised the 600 kDa sialylated glycoprotein as different from previously known tumour associated-marker antigens. Distribution of the Mab CF511-recognised antigen (CF511 antigen) in various tissues and sera was investigated. In immunohistochemical analysis, Mab CF511 reacted strongly with tumour cells of ovarian serous, clear cell, endometrioid and undifferentiated carcinoma and partially with those of mucinous carcinoma. Mab CF511 also reacted with breast carcinoma as well as lung carcinoma. In normal tissues, Mab CF511 cross-reacted with only five tissues, namely lung, breast, thyroid gland, fallopian tube and uterus. Serum levels of CF511 antigen were tested by ELISA inhibition using Mab CF511. This assay showed the circulating CF511 antigen levels to be elevated in 25 of 36 sera from patients with various clinical stages of common epithelial ovarian carcinoma compared to three of 47 and three of 111 sera from patients with other benign gynaecological diseases, including ovarian cysts, uterine fibroids with or without endometriosis and normal healthy subjects, respectively. For the relation between antigen levels and clinical stages of common epithelial ovarian carcinoma, greater than 34.0% ELISA inhibition was detected in 100% of patients with advanced stages (FIGO III and IV) compared with in 35.3% with early stages (FIGO I and II) patients. While patients with breast carcinoma (100%) and lung carcinoma (100%) also had elevated circulating CF511 antigen levels, patients with hepatoma, colorectal carcinoma and gastric carcinoma had no detectable elevation of antigen. Although the test showed a high degree of specificity, the detection of an elevated CF511 antigen level would not be so helpful in distinguishing patients with ovarian carcinoma from those with either breast carcinoma or lung carcinoma. These data suggest that CF511 antigen is a useful new ovarian tumour marker for diagnosis and management of the disease.

Adult↗
PubMed1989

Induction of interstitial nephritis in rats by basement membrane of human origin.

A study was conducted to investigate nephritogenic tubular basement membrane antigens common to human and rat kidneys. Brown Norway (BN) rats were immunized with human renal basement membrane in complete Freund's adjuvant simultaneously with Bordetella pertussis vaccine. The immunized rats developed polyuria and increased levels of serum creatinine one week after the second immunization. Renal histology at this time revealed marked, acute tubulointerstitial nephritis with linear deposition of IgG and C3 along the tubular basement membrane and Bowman's capsule, but not along the glomerular basement membrane. Rats with this tubulointerstitial nephritis rapidly developed antibodies against renal antigens from normal BN rats such as tubular basement membrane and proximal tubule brush border, however antibodies to glomerular basement membrane appeared later. Western blotting using the same rat sera detected a 145-kDa antigen from 8 M urea-solubilized human renal basement membrane and 120-kDa, 135-kDa and 145-kDa antigens from 8 M urea-solubilized BN rat renal basement membrane. This suggests that renal basement membranes of human and rat origin have common antigens involved in the pathogenesis of tubulointerstitial nephritis.

Animals↗
PubMed1989

An improved sensitive assay method for the heterogeneity of alpha-foetoprotein: possible application for early differential diagnosis.

A combination of lectin-affinity electrophoresis and antibody-affinity blotting was used for the qualitative determination of molecular species of alpha-foetoprotein. Concanavalin A and erythrophytohaemagglutinin were used as lectins. This method was able to quickly discriminate between the molecular species of alpha-foetoprotein of recurrent ovarian yolk sac tumour and those of non-malignant liver diseases and cord sera at term, using only 3 microliters of sera containing 200 micrograms/l of alpha-foetoprotein. The results indicate that this assay method might be useful for the differential diagnosis of recurrent yolk sac tumour from drug- or blood transfusion-induced liver diseases and for the monitoring of the serum alpha-foetoprotein level of patients with yolk sac tumour producing less than 200 micrograms/l of alpha-foetoprotein.

Antibodies↗
PubMed1989

Circulating tumor-associated antigen detected by the murine monoclonal antibody CF511 in human epithelial ovarian carcinoma.

The murine monoclonal antibody (Mab) to human common epithelial ovarian carcinoma, CF511, was generated by immunizing mice with human fetal tissue extract followed by a booster injection of ovarian cancer cells. Mab CF511 recognized the 600KD sialylated glycoprotein as being different from previously known tumor-associated marker antigens. Mab CF511 reacted with common epithelial ovarian carcinomas, and also reacted with breast and lung carcinoma. In normal tissue, Mab CF511 cross-reacted with the lungs, breast, thyroid, fallopian tubes and uterine endometrium. CF511 antigen was increased in sera of approximately 70% of the patients with common epithelial ovarian carcinoma. CF511 antigen levels in sera from patients with ovarian carcinoma corresponded to the clinical course. CF511 antigen was increased in only 3% of the 47 collections of sera from patients with benign gynecological diseases. These data suggests that CF511 antigen is a useful new ovarian tumor marker for the diagnosis and management of the disease.

Animals↗
PubMed1989

The effect of bispecific monoclonal antibody recognizing both hepatoma-specific membrane glycoprotein and anthracycline drugs on the metastatic growth of hepatoma AH66.

A monoclonal mouse antibody (MoHG) was produced using in vitro cultured AH66R tumor cells treated with cholesteryl hemisuccinate as an immunogen. The antibody identified a 90 kd membrane glycoprotein (HG-90) which is expressed on in vitro cultured hepatoma cell lines AH66 and AH66R. A monoclonal antibody was prepared to the anthracycline drug daunomycin, and it also reacted with adriamycin. A fusion was made of the hybridoma HG-90 with the hybridoma which recognized daunomycin/adriamycin. This bispecific hybridoma A8C recognized both determinants. We studied the therapeutic effect of the A8C bispecific antibody with adriamycin treatment and compared it to the effect of the bispecific antibody to which adriamycin had been conjugated via an albumin (Alb) bridge. The therapy model used was the tumor AH66R in Donryu rats. Tumor bearing rats had their subcutaneous tumors resected on day 10, a time when distant metastases were present. After the surgical resection of the tumor the rats were injected intravenously for two cycles with the bispecific antibodies, followed by the administration of adriamycin (ADR) or MoHG.Alb.ADR conjugates. A slight therapeutic effect occurred with either MoHG or ADR alone but treatment with the bispecific antibody followed by the administration of ADR or with the MoHG.Alb.ADR conjugates significantly prolonged survival, with 60% of the treated animals being "tumor free" when sacrificed on day 80. Lower serum concentrations of alphafetoprotein were observed with the bispecific antibody and drug treatment. This suggests that the bispecific antibody/drug treatment is potentially more beneficial in the suppression of distant metastases than the MoHG.Alb.ADR conjugate. This may be due to an increase in the local drug concentration of unmodified adriamycin.

Animals↗
PubMed1988

The effects of co-administration of selenium and cis-platin (CDDP) on CDDP-induced toxicity and antitumour activity.

The therapeutic antitumour activity and host toxicity of cis-platin (CDDP), which was administered with selenium (sodium selenite) was studied on the growth of a human yolk sac tumour grown in nude mice. Treatment consisted of CDDP single agent chemotherapy (3 weeks) or preliminary PVB combination chemotherapy (CDDP + vinblastine + bleomycin, 2 weeks). Selenium was co-administered from day 1 to 5 with each therapeutic regimen. The administration of CDDP alone caused significant reduction in tumour burden but at higher doses there was significant host toxicity. The co-administration of selenium together with CDDP (CDDP: selenium, molar ratio = 3.5:1) did not affect the anti-tumour activity of CDDP but it did cause a decrease of parameters of host toxicity including lethality, increasing the 50% lethal dose (LD50) from 9.3 mg kg-1 to 17.5 mg kg-1. The parameters of host toxicity which were altered by selenium co-administration were nephrotoxicity, myeloid suppression and weight loss. Our study suggested that selenium co-administration allows higher doses of CDDP with reduction of apparent toxicity, resulting in a higher therapeutic index and possibly indicating a potential increase in the utilization of CDDP in clinical cancer chemotherapy.

Animals↗
PubMed1987

Therapeutic effect of treatment with polyclonal or monoclonal antibodies to alpha-fetoprotein that have been conjugated to daunomycin via a dextran bridge: studies with an alpha-fetoprotein-producing rat hepatoma tumor model.

Purified monoclonal mouse or polyclonal horse antibodies (Ab) to rat alpha-fetoprotein (AFP) were conjugated with daunomycin via a dextran bridge. The therapeutic effect of these Ab-daunomycin conjugates on an AFP-producing rat hepatoma which was inoculated s.c. in Donryu rats was studied. Tumors (s.c.) and distant metastases were present by 14 days after tumor inoculation and the serum AFP level was 35 micrograms/ml. The injection of the Ab-daunomycin conjugate, started on day 14, significantly prolonged host survival with inoculated controls having a median survival of 25 days compared to 57 and 60 days for the treated groups. In a second study the Ab-daunomycin conjugates were injected i.v. every other day for five times after the surgical resection of the s.c. tumor. There was a slight therapeutic effect with either antibody or daunomycin alone but treatment with the AFP Ab-daunomycin conjugates significantly prolonged survival and 60% of these treated animals were "tumor free" when sacrificed on day 100. Serial quantitation of the concentration of AFP in the serum of the treated tumor-bearing or in the tumor-resected rats correlated with the therapeutic effectiveness of the Ab-daunomycin conjugates. These experiments show that the optimal treatment with specific antibody-drug conjugates will be in hosts where there is a small residual tumor burden such as may exist following resection of a primary tumor mass. They further show that the serial quantitation of serum AFP can be utilized to determine if residual tumor is present following treatment with Ab-daunomycin conjugates.

Animals↗
PubMed1986

Evaluation of a conjugate of purified antibodies against human AFP-dextran-daunorubicin to human AFP-producing yolk sac tumor cell lines.

The anticancer drug, DNR, was conjugated to an affinity-purified horse antibody to human AFP (aAFP) via a dextran bridge. The conjugate (immunoglobulin: DNR molar ratio, 1:50) was twice as potent as free DNR in an in vitro cytotoxicity assay against an AFP-producing human yolk sac tumor. The in vivo effect of aAFP, DNR, and the conjugate was tested against the human yolk sac tumor growing in nude mice. The conjugate, at a concentration of DNR containing the equivalent amount of 20 micrograms or 70 micrograms/mouse significantly retarded tumor growth whereas free aAFP showed only a slight inhibition of tumor growth compared to the PBS-treated control. Mice which received 20 micrograms/mouse of free DNR showed a moderate retardation of tumor growth whereas those which received 70 micrograms/mouse of DNR or a mixture of DNR and aAFP showed emaciation and early death due to acute toxicity of the drug. These results suggest that the anti-body-drug conjugate accumulated preferentially on the AFP-producing tumor cells and that cytotoxicity occurred.

Animals↗
PubMed1986

Selective in vitro and in vivo growth inhibition against human yolk sac tumor cell lines by purified antibody against human alpha-fetoprotein conjugated with mitomycin C via human serum albumin.

The anticancer drug mitomycin C (MMC) was conjugated with an affinity-purified horse antibody to human alpha-fetoprotein (aAFP) with human serum albumin (HSA) as the intermediate drug carrier. The conjugate (aAFP:HSA:MMC molar ratio, 1:1:30) retained full antibody binding activity as determined by a competitive binding radioimmunoassay. In a cytotoxicity test in which the AFP-producing human yolk sac tumor TG-1 cells were preincubated with test materials for 2 h followed by an additional 48-h culture in fresh medium, the conjugate was 20-fold more cytotoxic than free MMC at an equivalent MMC concentration of 100 ng/ml. The in vivo antitumor effect of the conjugate was tested against the human yolk sac tumor JOG-9 growing in athymic nude mice. When the tumor-bearing mice were treated with a total of 6 injections given on 2 consecutive days and then every other day starting 8 days after SC tumor inoculation [2 (equivalent MMC) microgram/head per injection], the conjugate retarded tumor growth more effectively than free MMC and normal horse immunoglobulin conjugate.

Adolescent↗
PubMed1986

[Anti-tumor activity of an anti-human alpha-fetoprotein antibody-human serum albumin-mitomycin C conjugate against human yolk sac tumor maintained in vitro and in nude mice in vivo].

The anti-cancer drug, mitomycin C (MMC), was conjugated to an affinity-purified horse antibody to human alpha-fetoprotein (aAFP) via purified human serum albumin (HSA) as an intermediate carrier. The conjugate (aAFP immunoglobulin (IgG): HSA: MMC, molar ratio 1: 1.10:29.8) was 21 or 38 times as cytotoxic as free MMC or PBS at the MMC concentration of 100 ng/ml, respectively, against alpha-fetoprotein-producing human yolk sac tumor in vitro. The in vivo effects of the conjugate and various controls were also tested against human yolk sac tumor growing in nude mice. The conjugate over a total of 6 injections retarded the initial tumor growth at the concentration of MMC, containing equivalent amounts of 2 micrograms/mouse (0.1 mg/kg)/injection in the conjugate, whereas free MMC and normal horse IgG-HSA-MMC showed only slight inhibitory effects alone at non-toxic levels. These results suggest that the specific antibody-conjugate was considerably more effective than free MMC against the tumor maintained in nude mice as well as in vitro cultures.

Animals↗
PubMed1985

Hormonal regulation during secretion of alpha-fetoprotein in hepatoma cells grown in synthetic medium.

The variant cell line of H4-II-E-C3 cells derived from the Reuber H-35 hepatoma cells has been established using protein- and lipid-free synthetic medium. This H4-II-E-C3-V line can synthesize and secrete considerable amounts of alpha-fetoprotein (AFP) and albumin. The addition of 5 X 10(-7) M dexamethasone to the medium stimulated the excretion of AFP without increasing total AFP synthesis, whereas 8.7 X 10(-8) M insulin inhibited the excretion of AFP without a significant inhibition of intracellular AFP synthesis. However, neither dexamethasone nor insulin altered either the cellular or secreted levels of albumin. Cells were pulse labeled with [35S]methionine and then chased after addition of excess unlabeled methionine. AFP appeared in the medium after 10 min, and 50% of the protein was secreted after 110 min. The rate of secretion of AFP was much slower than that of albumin, 50% of which was secreted after 25 min. Dexamethasone, 5 X 10(-7) M, caused a marked enhancement in the rate of AFP secretion, with 50% released after 75 min. Insulin, 8.7 X 10(-8) M, by contrast, caused a marked delay in AFP secretion with only 20% released after 180 min and then a plateau was approached. Since the intracellular AFP was excreted 55% after 180 min the remaining 25% of newly made AFP was suggested to be degraded during secretion. The kinetics of movement of AFP during secretion and endoglycosidase H treatment of intracellular and secreted AFP suggested that insulin impeded the transport of AFP from the rough endoplasmic reticulum to the Golgi apparatus.

Animals↗