Biomedical subjects

K Morikawa

Publications and source records attributed to K Morikawa.

At least 253 records · Page 14Linked to original sources

PubMed1988

Influence of organ environment on the growth, selection, and metastasis of human colon carcinoma cells in nude mice.

The purpose of these studies was to determine whether the biological and metastatic behaviors of tumor cells isolated from fresh surgical specimens of human colon carcinomas are influenced by the isolation method and the organ site of implantation and growth in nude mice. Three surgical specimens were obtained from three different patients. Two tumors were primary human colorectal carcinomas (HCC) classified as Dukes' B2 (KM12) and Dukes' D stages (KM20), and the third was from a liver metastasis (KM23). The tumors were enzymatically dissociated, and viable cells were implanted into the subcutis or spleen of different nude mice or were established in culture. Tumors developed in both sites of implantation, but hepatic metastases were found only in those nude mice that received splenic implantations of HCC cells. Cells from Dukes' D stage tumors produced more hepatic disease than cells from the Dukes' B tumor. Cells of the parental KM12C (culture) were injected into the spleen or cecum of nude mice to produce experimental and spontaneous hepatic metastases, respectively. HCC lesions were harvested from livers of nude mice and established as individual cell lines in culture. This procedure yielded cell lines KM12SM (spontaneous metastasis) and KM12L1 (experimental metastasis). The selection cycle for cells implanted into the spleen was repeated three more times to produce the cell line designated KM12L4. Cells of the parental KM12C and the three selected variants were injected into nude mice by different routes: i.v., s.c. into the cecum, and into the spleen. Subsequent to implantation into the spleen, all cell lines were shown to be tumorigenic. Cells from the selected KM12L4 and KM12SM lines produced a significantly higher number of experimental liver metastases than the parental cells. Moreover, subsequent to the injection into the cecum, cells of the once-selected KM12SM (for spontaneous metastasis) produced a higher incidence of spontaneous liver metastasis than all other lines. The human origin of all the lines was confirmed by isoenzyme and karyotype analyses. The two highly metastatic lines (KM12L4 and KM12SM) were tetraploid and produced elevated levels of type IV collagenolytic activity. Collectively, the results demonstrate that the orthotopic implantation of HCC cells into the appropriate organ environment can be used for efficient isolation and for study of metastatic subpopulations of cells from human colon carcinoma.

Animals↗

PubMed1988

Preliminary crystallographic study of pyrimidine dimer-specific excision-repair enzyme from bacteriophage T4.

Bacteriophage T4 endonuclease V, which is an excision-repair enzyme specific to pyrimidine dimers within DNA, has been crystallized from polyethylene glycol 4000 solution by a vapour diffusion technique. The unit cell is monoclinic, space group P2(1), with unit cell parameters: a = 41.4 A, b = 40.1 A, c = 37.5 A, beta = 90.01 degrees. The unit cell contains two 16,000 Mr molecules. The crystals diffract X-rays beyond 2.3 A resolution and are suitable for structural analysis at high resolution.

Crystallography↗

PubMed1988

Crystallization and preliminary crystallographic data of a truncated derivative from the human c-Ha-ras protein.

A truncated derivative of the human c-Ha-ras protein has been crystallized from polyethylene glycol 6000 solution by a vapour diffusion technique. The rectangular prism diffracts X-rays to at least 2.5 A resolution (1 A = 0.1 nm). The unit cell is monoclinic, space group P21, with unit cell parameters of a = 50.2 A, b = 110.9 A, c = 36.4 A, beta = 97.2 degrees. The unit cell contains four molecules.

Crystallization↗

PubMed1988

In vivo selection of highly metastatic cells from surgical specimens of different primary human colon carcinomas implanted into nude mice.

The purpose of these studies was to select and isolate cells with increased liver-metastasizing potential from heterogeneous primary human colon carcinomas (HCCs). Cells derived from a primary HCC classified as Dukes' stage B2 were directly established in culture or were injected into the subcutis, cecum, or spleen of nude mice. Progressively growing tumors were excised, dissociated, and established in culture. Subsequent to implantation into the cecum or spleen of nude mice, cells from all four lines produced only a few liver tumor foci. HCC cells from the few liver metastases were expanded in culture and then injected into the spleen of nude mice to provide a source for further cycles of selection. With each successive in vivo selection cycle, the metastatic ability of the isolated propagated cells increased. Four cycles of selection yielded cell lines with a very high metastatic efficiency in nude mice. In parallel studies using another primary HCC classified as Dukes' stage D, we isolated cell lines that were highly metastatic in nude mice. Successive selection cycles for growth in the liver increased the metastatic properties of the HCC cells, albeit to a lesser extent than it did those of the Dukes' B2 stage HCC. The ability of the HCC cells to produce liver metastases was not due to simple trapping in the liver. In vivo distribution studies using [125I] iododeoxyuridine-labeled tumor cells revealed that, shortly after injection into the spleen, a comparable number of cells with either low or high metastatic properties arrested in the liver. The differences between the low- and high-degree metastatic cells became apparent by 24 h after injection and, by 72 h, only highly metastatic cells survived in the liver. These results demonstrate that hepatic metastasis by HCC cells is a selective process and that the nude mouse model can be useful for isolating highly metastatic HCC cells and for studying the relevant host organ factors that regulate the pathogenesis of metastasis.

Animals↗

PubMed1988

Growth potential of human colorectal carcinomas in nude mice: association with the preoperative serum concentration of carcinoembryonic antigen in patients.

A preoperative serum carcinoembryonic antigen (CEA) concentration greater than 5 ng/ml portends a poor prognosis for patients with colorectal carcinoma. The purpose of this study was to determine if the tumorigenicity of colorectal carcinomas in nude mice was associated with the preoperative serum CEA concentration. Neoplasms from 53 patients were either implanted as fragments or dissociated with collagenase and DNase, and 3 x 10(6) viable cells were injected into the flanks of BALB/c nude mice. The growth potential of tumors resected from patients with CEA levels exceeding 5 ng/ml was greater than that of tumors from patients with normal serum CEA: 26 of 33 carcinomas from patients with CEA greater than or equal to 5 ng/ml were tumorigenic in nude mice, whereas only 8 of 22 neoplasms from patients with normal serum CEA were tumorigenic in nude mice (P less than 0.001). Primary colorectal cancers, not metastases, were the basis for the association between tumorigenicity and preoperative CEA. Tumorigenicity was also associated with stage of disease, since Dukes' D primary tumors and metastases were more tumorigenic than Dukes' A to C primary tumors. Growth in nude mice was not associated with other prognostic factors such as tumor site, mucin production, local invasion, or stage of histological differentiation. The tumorigenic capability of human colorectal carcinomas may be associated with the preoperative serum CEA concentration and may reflect an increased potential to develop clinical metastases.

Adult↗

PubMed1988

Modification of regression of virally xenogenized tumor cells by cyclophosphamide and busulfan.

Rat fibrosarcoma cells infected with Friend leukemia virus (FV-KMT-17) grow for a short time and then regress spontaneously in syngeneic hosts. This regression mechanism was examined by analyzing the immunomodulating action of the antitumor drugs busulfan (BU) and cyclophosphamide (CY). In preliminary experiments, the optimum dosages of BU and CY for the enhancement of DTH responses to SRBC were 10 mg/kg and 40 mg/kg respectively. Treatment of rats with BU (10 mg/kg) on day 5 induced the regression of KMT-17 cells, while in contrast, the same drug delayed the spontaneous regression of FV-KMT-17 cells. Pretreatment with CY (40 mg/kg) on day 5 did not affect the growth of KMT-17 or FV-KMT-17 cells. After the same treatment schedule, BU inhibited humoral antibody formation against SRBC and against virus-associated antigen (VAA), NK cell activity, and ADCC effector cell activity. On the other hand, CY did not affect the activities of NK cells or ADCC effector cells, although it significantly augmented the DTH responses to SRBC and the production of antibody to VAA but had no effect on production of antibodies to SRBC. These results suggest that NK cells and ADCC may play an important role in the initial stage of the spontaneous regression of FV-KMT-17 cells.

Animals↗

PubMed1988

Improved therapeutic effects of interleukin 2 after the accumulation of lymphokine-activated killer cells in tumor tissue of mice previously treated with cyclophosphamide.

We investigated the combined effects of human recombinant interleukin 2 (IL-2) and cyclophosphamide (CY) on s.c. transplanted 3LL lung carcinoma in C57BL/6 mice. A total of 95% of the tumors were completely cured when CY (150 mg/kg, i.v.) was given on day 5 (5 days after tumor implantation) and IL-2 (5 x 10(4) Jurkat Units/day, i.p.) was then combined with it between day 6 and day 15. CY alone brought about the complete regression of tumors, although 60% of the mice died of local recurrence and pulmonary metastasis; IL-2 alone had no therapeutic effect. Satisfactory effects from the combination of CY and IL-2 were also obtained by 5 days administration of IL-2 between days 11 and 15, initiated 6 days after CY treatment, but not by that given before CY (days 1-5) or 1 day after CY (days 6-10). No therapeutic effects from IL-2 were observed when it was combined with other types of chemotherapy that showed not therapeutic effects by themselves. Nor were we able to observe any transplantation resistance to the rechallenge of 3LL tumor in cured mice. We particularly examined the lymphokine-activated killer (LAK) cells as we suspected that these were responsible for the development of active effector cells in the treated mice. LAK cell activity in fresh spleen cells was detected in mice treated with IL-2 alone but not in untreated mice nor in those treated with CY alone or CY plus IL-2. The number of LAK precursor cells in the spleen had increased on day 8 and on day 13 in untreated mice with 3LL, as compared with the incidence in normal mice, while the number of cells had decreased by day 18. On the other hand LAK precursor cells were suppressed on day 8 and tended to recover thereafter in CY-treated mice. Adoptively transferred LAK cells were found to accumulate in CY-treated tumors 2.5 times more densely than in untreated tumors. The preferential accumulation of LAK cells that had been activated systemically by the appropriately timed administration of IL-2 in tumor tissue was followed by the improved effects obtained by combined treatment with CY and IL-2.

Animals↗

PubMed1988

In vitro activation of tumoricidal properties in mouse macrophages using the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) incorporated in liposomes.

We investigated the ability of free or liposome-incorporated synthetic chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) to generate tumoricidal properties in mouse macrophages. As FMLP contains three hydrophobic amino acid residues, it can readily be incorporated into multilamellar vesicles (MLV) consisting of phosphatidylcholine (PC) and phosphatidylserine (PS). The incorporation of FMLP into MLV with a PC:PS ratio of 7:3 mol at FMLP concentrations of up to 10(-4) M did not affect the phagocytosis of liposomes by mouse peritoneal macrophages. Studies with radioactive FMLP revealed that higher levels of FMLP can be delivered to macrophages by liposomes than in the free, nonencapsulated form. Treatment of mouse macrophages with liposome-encapsulated FMLP, but not with free FMLP, generated tumoricidal properties in the macrophages. The mechanism appears to involve an intracellular site since 100-fold concentrations of free FMLP or free N-acetyl-methionyl-leucyl-phenylalanine, the FMLP agonist, failed to competitively inhibit the macrophage's tumoricidal properties generated by liposome-encapsulated FMLP.

Animals↗

PubMed1988

Prevalence of HTLV-1 antibodies in hemodialysis patients in Japan.

The southwestern region of Japan is known as a very high endemic area of human T-cell lymphotropic virus type 1 (HTLV-1), the etiologic agent for adult T-cell leukemia (ATL) and probable causative agent for tropical spastic paraparesis and its Japanese version, HTLV-1-associated myelopathy (HAM). Hemodialysis (HD) patients seem to be at high risk for HTLV-1 infection even in other regions of Japan because they sometimes receive multiple blood transfusions. We examined antibody against ATL-associated antigen (ATLA-Ab) in 1,132 HD patients, including 1,066 patients in nonendemic areas (Chubu and Tokyo) and 66 in a highly endemic area (Okinawa). The HD patients in Okinawa showed the highest prevalence, 21.2% (14/66), while those in the Chubu area showed the lowest, 1.1% (10/846), and those in the Tokyo area an intermediate value, 2.7% (6/220). The prevalence of HD patients in each area was significantly higher than that of local blood donors, reflecting an increased prevalence roughly corresponding to the respective endemic rate. The average prevalence of ATLA-Ab among the HD patients was 2.7% (30/1,132), which was similar to that of HBs antigen (3.2%). In the nonendemic areas, 15 of 16 patients with ATLA-Ab had a history of blood transfusions, showing a significant correlation to the presence of ATLA-Ab (P less than 0.01), although four had family histories related to the endemic area. The relative risk of the presence of ATLA-Ab for HD patients with a history of blood transfusions was calculated as 10.3. In the endemic area of Okinawa, the relationship to blood transfusion was not so close, probably masked by the high background prevalence.

Adult↗

PubMed1988