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Biomedical subjects

M Namba

Publications and source records attributed to M Namba.

At least 307 records · Page 17Linked to original sources
PubMed1980

Decrease in blood glucose and release of gut glucagon-like immunoreactive materials by bombesin infusion in the dog.

Synthetic bombesin (100 ng/min) was infused under pentobarbital anesthesia in normal dogs and in insulin deprived depancreatized dogs 4 days after surgery. The release of gut glucagon-like immunoreactive materials (gut GLI) calculated as the difference between the values measured using cross-reacting antiserum and a so-called pancreatic glucagon specific antiserum was markedly stimulated by bombesin infusion. Plasma glucagon immunoreactivity (GI) measured by pancreatic glucagon specific antiserum also showed a small increase, whereas plasma glucose decreased significantly with a transient rise in insulin. The plasma glucose level did not decrease in depancreatized dogs. Gut GLI response in the regional mesenteric vein to 5% glucose administered into the loop of the ileum was strongly augmented by bombesin infusion. It is concluded that (1) bombesin infusion decreased blood glucose level in normal dogs but not in depancreatized dogs. (2) Bombesin infusion markedly augmented the release of GLI from the intestine. (3) Bombesin also stimulated the release of glucagon which was probably of gastrointestinal origin. (4) Insulin release was stimulated transiently by bombesin infusion. Thus, a competition of gut GLI with glucagon at the glucagon receptor site may be an explanation of the reduction in blood glucose.

Animals↗
PubMed1980

Fusion of transformed human cells by simian retroviruses.

Mason-Pfizer monkey virus (MPMV), baboon endogenous virus (BaEV) and simian sarcoma virus associated virus (SSAV) induced fusion in cultured human cells derived from tumors or transformed in vitro. Not only virus-transformed cells, but also cells transformed spontaneously by 4-nitroquinoline 1-oxide (4-NQO) treatment or by 60Co-gamma ray irradiation were fused by these simian retroviruses. Non-transformed cells derived from normal human embryos were not fused by any of these viruses. Of these tumor or transformed cells, cells carrying Rous sarcoma virus (RSV) genome were most extensively fused by these simian retroviruses. Anti-MPMV, anti-BaEV and anti-SSAV sera blocked the cell fusion mediated by MPMV, BaEV and SSAV, respectively, and not that by other viruses, indicating that the cell fusion was virus-specific.

Avian Sarcoma Viruses↗
PubMed1980

Effects of theophylline on the cell growth of normal and malignant human cells transformed in culture.

Proliferation of normal human diploid cell strains was inhibited to a greater extent by treatment with theophylline than the proliferation of neoplastic human cell lines transformed in culture with Co-60 gamma rays (WI-38 CT-1) or SV40 (WI-38 VA-13). Theophylline was added to cultures at final concentrations of 1 to 3 mM. Morphologically, normal fibroblasts became slender and small when grown in theophylline-containing medium, while little morphological change was observed in neoplastically transformed cells. Growth inhibition of theophylline was cytostatic rather than cytotoxic. No significant difference was detected in the uptake of theophylline between the normal and the transformed cells. Incorporation of 3H-thymidine into acid-insoluble fractions of cells began to decrease in the normal cells about 4 hr after adding theophylline to the culture medium. The intracellular contents of adenosine 3',5'-cyclic monophosphate increased linearly in the normal human cells with the time of treatment with theophylline, but no increase was observed in the transformed cells. The present results suggest that the use of theophylline might be useful for quantitative experiments on neoplastic transformation in cultures of normal human cells.

Cell Division↗
PubMed1980

Production of lung cancer an amyloidosis in rabbits by intrabronchial instillation of benzo[a]pyrene.

Carcinogenic activity of benzo[a]pyrene alone was tested for the induction of lung cancer in rabbits. Rabbits received intrabronchial instillation of 5 or 40 mg of benzo[a]pyrene suspended in sterile saline every 10 to 14 days. Cancer incidences were approximately 42% of the rabbits that survived for more than 300 days. These cancers included squamous cell carcinoma, adenocarcinoma, undifferentiated cell carcinoma, fibrosarcoma, and mixed type. In the same experiment amyloidosis was seen in 16 rabbits.

Adenocarcinoma↗
PubMed1980

Characteristics of WI-38 cells (WI-38 CT-1) transformed by treatment with Co-60 gamma rays.

The characteristics of WI-38 CT-1 cells, which had been transformed by treatment with Co-60 gamma rays, were compared with those of the control WI-38 cells in order to identify parameters of malignant transformation in cultures of normal human diploid cells. The transformed WI-38 CT-1 cells were different from the control WI-38 cells in the following respects: (1) epithelial-like morphology of the cells, (2) reduced serum requirement for cell proliferation, (3) increased colony formation in soft agar, (4) increased saturation density, and (5) resistance to the cytostatic effect of theophylline on cell proliferation. On the other hand, no appreciable difference was detected between the control and the transformed cells in (1) population doubling time and (2) sensitivity to Co-60 gamma rays.

Agar↗
PubMed1980

Effect of Nocardia rubra cell-wall skeleton on the induction of lung cancer and amyloidosis by 3-methylcholanthrene in rabbits.

Repeated intravenous administrations of oil-attached Nocardia rubra cell-wall skeleton (N. rubra-CWS) prevented the induction of lung cancer by intrabronchial instillations of 3-methylcholanthrene in rabbits. Amyloidosis was seen after giving 3-methylcholanthrene, and the incidence was higher in the N. rubra-CWS administered rabbits than in the controls.

Adenoma↗
PubMed1979

Creutzfeldt-Jakob disease--alteration in ganglioside sphingosine in the brain of a patient.

Gangliosides isolated from the brain of patients with Creutzfelt-Jakob (C-J) disease were analyzed. The ganglioside current was abnormally low, and the percentage distributions of individual gangliosides and the long-chain base compositions were abnormal. The C20-sphingosine contents of all the ganglioside fractions were low. Abnormalities in ganglioside long-chain bases in adult human brain have been reported previously only in patients with inherited metabolic disorders. These abnormalities in C-J disease seem to be closely related to the cause of the disease.

Brain Chemistry↗
PubMed1979

Ultrastructure of acetylcholinesterase containing striato-nigral neurons transporting HRP retrogradely.

The fine structure of striato-nigral efferent neurons, retrogradely labeled with HRP, was studied. The neuron showed a medium sized ovoid or tri-angular perikaryon. Short or medium lengthened granular endoplasmic reticula, having a tendency to wind and pile up in stacks were observed. This neurons corresponds to a type III neuron according to our classification [4,5]. The neuron showed reaction products, indicating AChE activity, in the granular endoplasmic reticula and plasma membrane.

Acetylcholinesterase↗
PubMed1979

Culture of normal human epidermal cells with 3T3 feeders on millipore filters.

Human epidermal cells were cultured with lethally irradiated 3T3 cells and grew as large colonies both on plastic and millipore filters. Subcultures were possible. The grown colonies were studied morphologically and histologically. The whole intact crossview of epidermal colonies in paraffin sections was obtained from the cell culture on millipore filters. The epidermal cells derived from younger persons had higher efficiency of colony formation than those from older ones. The membrane filter was shown to be good substratum for epidermal cell growth as well as plastic.

Adult↗
PubMed1979

An attempt for improving plating efficiency of human diploid fibroblasts.

An attempt was made to enhance the plating efficiency of normal human diploid skin fibroblasts by testing various culture media. Eagle's minimum essential medium (MEM), Dulbecco's MEM, William's medium E, DM-160, McCoy's 5a, RPMI-1640, Ham's F12, MCDB 102, Waymouth's MB 752/1, and L-15 synthetic media were examined. L-15 was the best among them. Plating efficiency with L-15 supplemented with 20% calf serum ranged from 20 to 60%. Plating efficiency decreased in the order of Eagle's MEM, Dulbecco's MEM, DM-160, and Ham's F12. Waymouth's MB 752/1, MCDB 102 McCoy's 5a, RPMI-1640, and William's medium E were not favorable for high plating efficiency. Although L-15 gave the best plating efficiency and Waymouth's MB 752/1 the worst, the Waymouth medium supported better cell proliferation than L-15, when cell proliferation was compared in mass culture with these two media. It was concluded that L-15 was better suited for culture of small number of cells, and especially for work involving colony formation.

Cell Division↗
PubMed1979

Effect of Nocardia rubra cell-wall skeleton on the induction of lung cancer in ACI/N rats.

Administration of oil-attached Nocardia rubra cell-wall skeleton (N. rubra-CWS) was evaluated for the effect of the induction of lung cancers in ACI/N rats. Lung cancers were induced by 15 weekly intratracheal instillations of 3 mg benzo[a]-pyrene with 3 mg ferric oxide. After the 10th instillation of the carcinogen, rats received seven subcutaneous injections of 100 microgram of N. rubra-CWS at 2-week intervals. In the observation period of 56 weeks, the cumulative incidence of lung cancer was 71.4% in the control group and 48.0% in the N. rubra-CWS treated group. The latent period of tumor induction was prolonged in the group treated with N. rubra-CWS.

Animals↗