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M Namba

Publications and source records attributed to M Namba.

At least 235 records · Page 13Linked to original sources
PubMed1986

Effects of decapeptide of mammalian bombesin and neuromedin B on pancreatic exocrine secretion in the rat.

The effects on pancreatic exocrine secretion of intravenous bolus injections of decapeptide of mammalian bombesin (also called neuromedin C) and neuromedin B, recently isolated mammalian bombesin-like peptides, have been studied and compared with those of amphibian bombesin in anaesthetized rats. Decapeptide of mammalian bombesin and neuromedin B stimulated the volume output from the pancreas with the same potency as that with which they stimulated protein output, as did amphibian bombesin. The maximal peak rates of volume and protein secretion observed in the 5- to 10-min period after the injection of 3 X 10(-10) mol/kg decapeptide of mammalian bombesin were 24.5 +/- 1.2 microliters/5 min and 8.5 +/- 0.5 mg bovine serum albumin equivalents per 5 min (mean +/- SEM, n = 5). These rates were equivalent to those produced by the same dose of amphibian bombesin, but the duration of responses to decapeptide of mammalian bombesin were shorter than those of equimolar doses of amphibian bombesin. The relative potencies of decapeptide of mammalian bombesin and neuromedin B, calculated from the doses producing 50% of maximum effect on total responses, were, respectively, 100 and 0.5% of that of amphibian bombesin. The results suggest that decapeptide of mammalian bombesin, and possibly neuromedin B, could play a regulatory role in the control of exocrine pancreatic secretion.

Animals↗
PubMed1986

Histological and pharmacological investigations of the two symmetrically situated giant neurons, RPeNLN and LPeNLN, identified on the anterior surface of the pedal ganglia of an African giant snail (Achatina fulica Férussac).

Morphological and pharmacological investigations were made of two giant neurons, RPeNLN (right pedal nerve large neuron) and LPeNLN (left pedal nerve large neuron), situated symmetrically on the anterior surface of the pedal ganglia of an African giant snail (Achatina fulica Férussac). The two neurons (about 250-300 microns in diameter) were the largest ones identified in the ganglia of the snail species. The axonal pathways of the two neurons were symmetrical; of their four main axonal branches, the three main branches innervated the ipsilateral pedal nerves, whereas the last main branch projected to the contralateral pedal nerves. The pharmacological features of the two neurons were very similar. Both were inhibited markedly by dopamine [minimum effective concentrations (MECs): 3 X 10(-6)-10(-5) M], DL-octopamine (MECs: 2 X 10(-6)-2 X 10(-5) M), 5-hydroxytryptamine (MEC: 3 X 10(-6) M), GABA (MEC: 3 X 10(-4) M), L-homocysteic acid (MECs: 3 X 10(-5)-10(-4) M) and erythro-beta-hydroxy-L-glutamic acid (MEC: 3 X 10(-5) M). Acetylcholine showed varied effects, either excitatory or inhibitory, on the two neurons examined. No substances were found to have any marked excitatory effects on the neurons.

Animals↗
PubMed1986

Colon carcinoma K-ras 2 oncogene of a familial polyposis coli patient.

The DNA of a colon carcinoma-derived cell line (KMS-4) and that of skin fibroblasts from a familial polyposis coli patient were transfected into NIH3T3 cells in order to detect oncogenes associated with the disease. No transformation was observed with the normal skin fibroblast DNA, while the KMS-4 cell DNA was able to transform NIH3T3 cells. Through hybridization with known oncogene probes, the KMS-4 transforming gene was found to be a human activated c-K-ras 2 oncogene. Sequence analysis of the molecularly cloned KMS-4 c-K-ras 2 oncogene showed a single nucleotide transition from G to T at the 12th codon. This results in substitution of cysteine for glycine at this position. On using labeled synthetic oligonucleotides to detect the mutation in codon 12, we found the G to T transition in colon carcinoma cells. This suggests that activation of the c-K-ras 2 oncogene could be associated with colon carcinoma induction.

Adenomatous Polyposis Coli↗
PubMed1986

Macrophage tumoricidal activity as a possible antitumor mechanism associated with the local injection of allogeneic spleen cells into rats.

The in vivo antitumor effect of i.p. injection of allogeneic spleen cells was investigated. ACl rats were inoculated i.p. with 10(4) AMC-60 syngeneic fibrosarcoma cells and given injections i.p. of 4 X 10(7) Wistar spleen cells once a week for 3 wk from 1 day after tumor inoculation. This treatment significantly prolonged the survival period of the tumor-bearing rats. A similar effect was obtained by i.p. injections of Lewis spleen cells. Injection i.p. into ACl rats of spleen cells of these rat strains resulted in the apparent augmentation of cytolytic activity of peritoneal adherent but not of nonadherent cells against AMC-60 tumor cells. The cytotoxicity was exhibited nonspecifically to cells of a variety of tumor lines but not to concanavalin A blasts of ACl spleen cells and was inhibited by the addition of carrageenan. Irradiation (2000 R) of Lewis spleen cells or fractionation of the allogeneic spleen cells using nylon wool columns revealed that a radiosensitive and nylon wool-passed cell population, presumably a T-cell population, of the allogeneic spleen cells is responsible for the augmentation of peritoneal macrophage tumoricidal activity in ACl rats. Further, Lewis spleen cells irradiated at 2000 R neither augmented peritoneal macrophage cytotoxicity nor prolonged the survival period of ACl rats bearing AMC-60 tumor, suggesting that the augmentation of peritoneal macrophage cytotoxicity plays a major role in the in vivo antitumor effect of the allogeneic spleen cell transfer. ACl rats were given injections i.p. of 4 X 10(7) Lewis spleen cells. Two days after injection, cells including peritoneal cells of the ACl rats and Lewis spleen cells remaining in the peritoneal cavities were obtained by peritoneal lavages and then incubated for 5 days. Significant blastogenic proliferation was observed, and the supernatant of the culture was shown to be able to render thioglycollate-induced peritoneal macrophages of ACl rats cytotoxic to AMC-60 tumor cells, indicating that a certain cell population of the cell mixture produced a lymphokine(s) resembling macrophage activating factor (MAF) during the incubation. When ACl rats were given injections i.p. of irradiated Lewis spleen cells, neither the blastogenic proliferation nor the generation of MAF activity in the culture supernatant was observed. Indirect immunofluorescence analysis using rabbit anti-ACl and anti-Lewis antisera revealed that as many irradiated Lewis spleen cells were remaining in the peritoneal cavities as normal Lewis spleen cells 2 days after injection into ACl rats.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Distribution and chromatographic characterization of neuromedin B-like immunoreactivity in the human spinal cord.

The quantitative regional distribution of neuromedin B-like immunoreactivity in normal postmortem human spinal cord was studied by a specific radioimmunoassay. Neuromedin B-like immunoreactivity was found in highest concentration in the dorsal part of the sacral cord. Chromatographic analyses by gel permeation and reverse-phase high-pressure liquid chromatography revealed two major peaks of neuromedin B-like immunoreactivity and the prevalent molecular form, approx. 90% of the total immunoreactivity, was chromatographically identical to synthetic porcine neuromedin B.

Aged↗
PubMed1985

Neoplastic transformation of human diploid fibroblasts (KMST-6) by treatment with 60Co gamma rays.

Normal fibroblasts (KMS-6) derived from a human embryo were transformed in culture into neoplastic cells (KMST-6) by repeated treatment with 60Co gamma ray irradiation. Repeated treatment was necessary to obtain transformation. Control normal cells exhibited normal karyotype (46, XX) and stopped dividing due to cellular ageing at the 40th passage. The transformed cells are presently growing indefinitely (140th passage) and exhibit prominent karyologic aberrations, both numerical and structural. These 2 characteristics, indefinite growth and abnormal karyotype, are thought to be the most important parameters for neoplastic transformation of human fibroblasts. Other indispensable parameters are the presence of active mitotic figures on confluent cell sheets and colony-type morphology. Transformed cells grow into colonies with relatively smooth edges, while normal fibroblasts form colonies with jagged edges, due to the protrusion of growing fibroblasts. Other parameters, such as elevated plating efficiency, enhanced colony formation in soft agar, low serum requirement for growth, high saturation density, and acquisition of transplantability, are not reliable in the early stages of transformation. These parameters probably appear at rather later stages of transformation following several cell divisions. Among other characteristics, the transformed KMST-6 cells exhibit a B-type isozyme pattern of glucose-6-phosphate dehydrogenase, lactate-dehydrogenase isozyme pattern of human origin, no evidence of viral infection and no production of C-type virus particles.

Cell Line↗
PubMed1985

Relationship of finite proliferative lifespan, senescence, and quiescence in human cells.

Cell hybrids were formed between human diploid fibroblasts (HDF) and carcinogen-transformed HDF to determine the relationship among: (1) finite proliferative lifespan, which we define as an age-related failure of a population to achieve one population doubling in 4 weeks; (2) arrest in a senescent state, which we define as cessation of DNA synthesis in a viable culture that is at the end of its lifespan by the above definition; and (3) arrest in a quiescent state, which we define as cessation of DNA synthesis in a young culture that is crowded or mitogen-deprived. HDF express all three of these phenotypes, which we have abbreviated FPL+, S+, and Q+, respectively. Carcinogen-transformed HDF are transformed to immortality (FPL-) and inability to achieve quiescence (Q-). They have no S phenotype because, by definition, this phenotype only exists in FPL+ cells. Fusion of FPL+, Q+, S+ HDF X FPL-, Q- carcinogen-transformed HDF produced hybrid clones that were FPL+, Q-, and S-, where the S- phenotype means that individual cells continued to synthesize DNA in cultures that had reached the end of their lifespan by our definition. These results are consistent with our hypothesis that senescent HDF and quiescent HDF may share a common mechanism for arrest in G1 phase. We have suggested that this could occur if the aging mechanism that is responsible for the FPL+ phenotype is a progressive decrease in the ability of cells to recognize or respond to mitogenic growth factors. If so, then cells would become physiologically mitogen-deprived at the end of their lifespan, which would cause them to arrest in the senescent state by the same mechanism that causes young cells to arrest in the quiescent state when they are mitogen-deprived. This hypothesis predicts that the FPL+ phenotype can be separated from the S+ phenotype--i.e., FPL+ cells can be S+ or S- --and that the Q and S phenotypes are linked--i.e., FPL+ cells are either Q+ and S+ or Q- and S-. Both these predictions are supported by the present data.

Cell Division↗
PubMed1985

Presence of neuromedin B-like immunoreactivity in the brain and gut of rat and guinea-pig.

A recently developed specific radioimmunoassay for neuromedin B, originally isolated from porcine spinal cord, was used to investigate its distribution in rat and guinea-pig brain and gut. In both species, neuromedin B-like immunoreactivity was present in several regions of brain, and high concentrations occurred in the pituitary. The immunoreactivity was widely distributed throughout the entire length of gastrointestinal tract and pancreas, and relatively high concentrations were found in the oesophagus and rectum. Immunocytochemistry localised neuromedin B-like immunoreactivity to nerve fibers in the rat brain and gut. Immunoreactive fibres were visualized in the medial thalamus and were found very frequently in the circular muscle of the gut. Gel permeation chromatography of pituitary and intestinal extracts from both species revealed presence of two peaks of neuromedin B-like immunoreactivity, the later of which co-eluted with the synthetic porcine neuromedin B standard. Reverse phase high pressure liquid chromatography showed that material corresponding to the later peak was eluted in the exact position of synthetic porcine neuromedin B, whereas the larger molecular size material from the earlier peak was more hydrophobic in nature.

Amino Acid Sequence↗
PubMed1985

Distribution and localization of neuromedin B-like immunoreactivity in pig, cat and rat spinal cord.

The distribution and localization of neuromedin B, a novel bombesin-like decapeptide isolated from porcine spinal cord, was investigated by newly established radioimmunoassay and immunocytochemistry in the pig, cat and rat spinal cord. Neuromedin B-like immunoreactivity was found to be concentrated particularly in the dorsal part of lumbosacral segments in all species studied and the highest concentration of immunoreactivity was 25.7 +/- 3.4 pmol/g wet wt in the dorsal part of sacral region of pig spinal cord. The nature of the immunoreactivity was studied by gel permeation and high pressure liquid chromatography. Chromatography of spinal cord extracts from three species revealed two major peaks of neuromedin B-like immunoreactivity and the prevalent molecular from co-eluted with synthetic porcine neuromedin B. Immunocytochemistry localized neuromedin B immunoreactivity to fibres and terminals throughout the entire length of the spinal cord of pig, cat and rat. Fibres were most abundant in laminae I and II of the dorsal horn, the area around the central canal (lamina X) and intermediolateral cell columns of thoracic and sacral segments. In lumbosacral segments neuromedin B-immunoreactive fibres were slightly more numerous, in both dorsal and ventral spinal cord, than in cervical and thoracic regions.

Animals↗
PubMed1985

Actions of exogenous heparan sulfate and hyaluronic acid on growth and thymidine incorporation of normal and transformed human fibroblasts. A comparison with the effects of high cell density and low serum concentration and a warning against thymidine incorporation as a measure of DNA synthesis.

Treatment of normal human (WI-38) cells with exogenous heparan sulfate (HS) reduced cell growth and incorporation of radio-isotope-labeled thymidine (TdR) into DNA. In spite that growth of their transformants (WI-38 CT-1) was enhanced by HS treatment, transformed cells also decreased in TdR incorporation thereby. This peculiar observation was explained by a reduction of TdR uptake, leading to a decrease in specific radioactivity of newly synthesized DNA. The changes in cell growth and TdR incorporation by HS treatment were revealed to be similar to the changes with increasing cell density rather than by serum starvation.

Biological Transport↗
PubMed1985

Unaltered stimulation of pituitary adrenocorticotrophin secretion by corticotrophin-releasing factor following sodium valproate administration in a patient with Nelson's syndrome.

A 53-year-old woman with Nelson's syndrome was treated with 600 mg sodium valproate daily. Her plasma ACTH was effectively decreased, whilst the response of plasma ACTH to corticotrophin-releasing factor (CRF) was unaltered. The result of the CRF test suggested that sodium valproate, at least in the present patient, acted at the hypothalamic level.

Adrenocorticotropic Hormone↗
PubMed1985

Comparison of detection of oligoclonal immunoglobulin G bands in cerebrospinal fluid specimens by Coomassie blue and silver stains.

Cerebrospinal fluid (CSF) specimens from 45 clinically definite MS patients were studied for the presence of oligoclonal IgG bands by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The protein bands were identified by Coomassie blue (CB) dye and silver staining. Thirteen patients showed no bands in their CSF by the CB method. Nine of these 13 patients showed presence of bands by silver staining alone. Thirty-two patients showed more than two bands in their CSF by either technique, and 28 of the 32 patients showed from one to five additional bands by silver staining compared to Coomassie blue staining. The silver staining method was thus more sensitive in identification of oligoclonal bands in CSF.

Clone Cells↗
PubMed1984

In vitro and in vivo studies on potentiation of cytotoxic effects of anticancer drugs or cobalt 60 gamma ray by interferon on human neoplastic cells.

A possibility that interferon may potentiate the cytotoxic effects of anticancer drugs or 60Co gamma ray on human neoplastic cells was studied by in vitro and in vivo experimental procedures. The human neoplastic cells used were HeLa (uterine cervical cancer) and WI-38 CT-1 (embryonic lung fibroblasts transformed in culture by 60Co gamma ray) cells. As normal human cells, WI-38 cells were used. Interferon was a preparation of beta-type produced by human fibroblasts. The cytotoxicity was determined by colony formation for in vitro experiments and by tumor growth for animal experiments. Of 17 anticancer drugs, the cytotoxic effects of six drugs, namely, peplomycin, bleomycin, aclacinomycin, cisplatin, 5-fluorouracil (5-FU), and Adriamycin (doxorubicin) were potentiated by concomitant application of interferon. The cytolethal effects of 60Co gamma ray were also enhanced by interferon. The growth of tumor induced by transplantation of HeLa cells into a nude mouse was remarkably reduced by combination therapy of interferon and 5-FU. The current results indicate a possibility that combined therapy of certain types of anticancer drugs or 60Co gamma ray with interferon may be effective in treatment of cancer patients.

Animals↗
PubMed1984

Differential growth response of normal human diploid fibroblasts and in vitro transformed human fibroblasts in serum-free defined culture medium.

Two neoplastic human cell lines, WI-38 CT-1 and SUSM-1, which were transformed in vitro with gamma rays and 4-nitroquinoline 1-oxide, respectively, grew continuously in a serum-free defined medium. The defined medium used was a 1:1 mixture by volume of Dulbecco's modified Eagle's medium and Ham's F12 (DF) supplemented with 0.1% bovine serum albumin fraction V, 10 micrograms/ml of transferrin, 1 microgram/ml of insulin, and 5 micrograms/ml of oleic acid. In the case of SUSM-1, 100 micrograms/ml of fetuin were added to cultures when the cells were subcultured. Under these conditions the growth rates of the two transformed human cell lines were almost the same as those in a DF medium containing 10% fetal bovine serum (FBS). In addition, the defined medium permitted the cells to grow indefinitely without a lag period when they were transferred from serum-containing medium into this defined medium, indicating that no selection or adaptation of the cells had occurred. Interestingly, these cell lines did not require for their growth any polypeptide growth factors such as epidermal, platelet-derived or fibroblast growth factors. On the other hand, the control WI-38 cells stopped growing in the defined medium after about 2 divisions. Another control normal cell strain of fibroblasts derived from a human embryo showed a decreased growth rate in the defined medium as compared with that in the DF medium with 10% FBS. These results suggest that the defined medium described here is useful for the selective growth of human cells transformed in vitro after treatment with carcinogens from an untransformed cell population. In addition, the defined medium for transformed human cells should contribute to studies on their growth mechanisms.

Cell Division↗