The accuracy of fine needle aspiration cytology in the clinical diagnosis of minor salivary gland tumours

The objective of this study was to investigate the accuracy of fine needle aspiration cytology (FNAC) and biopsy for the clinical diagnosis of minor salivary gland tumours (MSGTs). This retrospective study of 32 MSGT cases was conducted over a 5-year period. Clinical features including age, sex, and location of the tumour were obtained from the patient clinical records. All cases were also assessed histologically according to the 2017 World Health Organization Classification of Head and Neck Tumours. The results of FNAC and biopsy were correlated with those of histopathology, and their sensitivity, specificity, and diagnostic efficacy were calculated using histopathology as the gold standard. Eighteen malignant MSGTs (56.3%) and 14 benign MSGTs (43.8%) were diagnosed by pathological diagnosis. The most common malignant tumour was mucoepidermoid carcinoma (seven cases, 38.9%). Most benign cases were pleomorphic adenomas (13 cases, 92.9%). FNAC was performed for 23 cases and biopsy for 13 cases. The sensitivity and specificity of FNAC were 66.7% and 91.0%, respectively, while those of biopsy were 90.0% and 100.0%, respectively. Although FNAC is a minimally invasive and cost-effective procedure, it is less accurate than biopsy in the assessment of MSGTs. Repeated FNAC or biopsy should be considered in negative and unsatisfactory FNAC cases.

Single pancreatic beta cells co-express multiple islet hormone genes in mice

AIMS/HYPOTHESIS

It is widely accepted that production of insulin, glucagon, somatostatin and pancreatic polypeptide in islet cells is specific to beta, alpha, delta and pancreatic polypeptide cells, respectively. We examined whether beta cells express other genes encoding islet hormones.

METHODS

Nested RT-PCR was performed on single beta cells of transgenic mice with green fluorescent protein (GFP) driven by mouse insulin I promoter (MIP-GFP).

RESULTS

Only 55% of adult beta cells expressed the insulin gene alone, while others expressed two or more islet hormone genes; 4% expressed all four hormone genes. In embryonic and neonatal cells, 60% to 80% of GFP(+) cells co-expressed pancreatic polypeptide and insulin genes in contrast to 29% in adult. To clarify cell fate, we conducted lineage tracing using rat insulin II promoter-cre mice crossed with reporter mice Gt(ROSA)26Sor-loxP-flanked STOP-cassette-GFP. All GFP(+) cells expressed insulin I and II genes, and showed similar heterogeneity of co-expression to that seen in MIP-GFP mice. Although we report expression of other hormone genes in a significant proportion of beta cells, our lineage tracing results demonstrate that after inducing InsII (also known as Ins2) expression, beta cell progenitors do not redifferentiate to non-beta cells.

CONCLUSIONS/INTERPRETATION

This study shows co-expression of multiple hormone genes in beta cells of adult mice as well as in embryos and neonates. This finding could: (1) represent residual expression from beta cell precursors; (2) result from alternative developmental pathways for beta cells; or (3) denote the differentiation potential of these cells. It may be linked to functional heterogeneity. This heterogeneity in gene expression may provide a means to characterise the functional, cellular and developmental heterogeneity seen in beta cells.

Towards better understanding of the contributions of overwork and glucotoxicity to the beta-cell inadequacy of type 2 diabetes

Type 2 diabetes (T2D) is characterized by reduction of beta-cell mass and dysfunctional insulin secretion. Understanding beta-cell phenotype changes as T2D progresses should help explain these abnormalities. The normal phenotype should differ from the state of overwork when beta-cells compensate for insulin resistance to keep glucose levels normal. When only mild hyperglycaemia develops, beta-cells are subjected to glucotoxicity. As hyperglycaemia becomes more severe, so does glucotoxicity. beta-Cells in all four of these situations should have separate phenotypes. When assessing phenotype with gene expression, isolated islets have artefacts resulting from the trauma of isolation and hypoxia of islet cores. An advantage comes from laser capture microdissection (LCM), which obtains beta-cell-rich tissue from pancreatic frozen sections. Valuable data can be obtained from animal models, but the real goal is human beta-cells. Our experience with LCM and gene arrays on frozen pancreatic sections from cadaver donors with T2D and controls is described. Although valuable data was obtained, we predict that the approach of taking fresh samples at the time of surgery is an even greater opportunity to markedly advance our understanding of how beta-cell phenotype evolves as T2D develops and progresses.

Differentiation of COPAS-sorted non-endocrine pancreatic cells into insulin-positive cells in the mouse

AIMS/HYPOTHESIS

The regenerative process in the pancreas is of particular interest, since insulin-producing beta cells are lost in diabetes. Differentiation of new beta cells from pancreatic non-endocrine cells has been reported in vivo and in vitro, a finding that implies the existence of pancreatic stem/progenitor cells. However, while tissue-specific stem cells are well documented in skin, intestine and testis, pancreatic stem cells have been elusive. We hypothesised that pancreatic stem/progenitor cells within the non-endocrine fraction could be a source of new islets in vitro.

METHODS

To test if there were such cells within the pancreas, we generated pancreatic cell aggregates from tissue remaining after islet isolation from mouse insulin promoter 1-green fluorescent protein (MIP-GFP) mice. To eliminate any contamination of insulin-positive cells, we deleted all GFP-positive aggregates using COPAS Select and cultured with Matrigel. Immunohistochemistry, quantitative real-time PCR and single-cell nested RT-PCR were performed to confirm formation of insulin-producing cells.

RESULTS

The GFP-negative cells were expanded as monolayers and then differentiated into three-dimensional cystic structures. After 1 week of culture, GFP-positive cells were found as clusters or single cells. By quantitative real-time PCR, no insulin mRNA was detected immediately after COPAS sorting, but after differentiation insulin mRNA of the whole preparation was 1.91 +/- 0.31% that of purified MIP-GFP beta cells. All GFP-positive cells expressed insulin 1; most expressed insulin 2, pancreas duodenum homeobox-1 and cytokeratin 19 by single cell nested RT-PCR.

CONCLUSIONS/INTERPRETATION

Our data support the concept that within the exocrine (acinar and ductal) pancreas of the adult mouse there are cells that can give rise to insulin-positive cells in vitro.

In vivo evaluation of ocular inflammatory responses in experimental diabetes

AIMS

Diabetic patients may have abnormal inflammatory reactions to foreign or endogenous stimuli. This study was designed to evaluate inflammatory reactions in the diabetic eye through retinal leucocyte dynamics in the inflamed eyes of diabetic rats.

METHODS

Three weeks after diabetes induction in Long-Evans rats, endotoxin induced uveitis was produced by footpad injection of lipopolysaccharide (LPS). After LPS injection, leucocyte behaviour was evaluated in vivo by acridine orange digital fluorography.

RESULTS

The number of rolling leucocytes increased in a biphasic manner at 12 hours and 48 hours. The number of leucocytes accumulating in the retina reached a peak at 72 hours. The maximal numbers of rolling and accumulating leucocytes in the diabetic retina decreased by 56.3% (p<0.01) and 46.7% (p<0.0001), respectively, compared with the non-diabetic retina. The levels of mRNA expression of adhesion molecules in the retina, which were upregulated after LPS injection, were also lower in diabetic rats than in non-diabetic rats.

CONCLUSION

This study is the first to show that endotoxin induced inflammation is disturbed in the diabetic eye, based on evidence that the leucocyte-endothelial cell interactions stimulated by LPS were suppressed in the diabetic retina. These findings support the theory that ocular inflammatory reactions are impaired in diabetic patients.

Mastoparan stimulates GABA release from MIN6 cells: relationship between SNARE proteins and mastoparan action

We examined the action of mastoparan on beta cell exocytosis. Mastoparan stimulated GABA and insulin release from MIN6 beta cells. On the other hand, mastopraran-induced GABA release was decreased by expressing the tetanus toxin C1 light chain in MIN6 cells. We have then investigated the relationship between SNARE proteins and mastoparan action using adenovirus-mediated gene transfer system. Overexpression of t-SNAREs, syntaxin 1A, and SNAP-25 inhibited the mastoparan-induced insulin release by approximately half-fold of control levels, however, the mastoparan-induced GABA release was not affected by these t-SNAREs overexpression. The overexpression of mutant alpha-SNAP (1-285), which inhibits the wild-type alpha-SNAP function in a dominant negative manner, did not influence either mastoparan-induced GABA or insulin release in spite of its marked inhibition of glucose-stimulated insulin release. Our data indicate that mastoparan stimulates GABA exocytosis via vesicular transport; however, SNARE proteins are differently involved in the exocytosis of insulin and GABA.

Transforming growth factor-beta 2 levels in aqueous humor of glaucomatous eyes

PURPOSE

To determine whether clinical characteristics are correlated with increased levels of transforming growth factor-beta 2 (TGF-beta 2) in aqueous humor in glaucomatous eyes.

METHODS

Aqueous humor samples were collected from 91 glaucomatous eyes. Included were samples from primary open-angle glaucoma (POAG) in 40 eyes, (pseudo)exfoliation syndrome (EXS) in 18 eyes, primary angle-closure glaucoma (PACG) in 26 eyes and uveitis-related secondary glaucoma (SG) in 7 eyes. TGF-beta 2 in aqueous humor was assessed with a specific-capture ELISA.

RESULTS

The mean concentration (+/- standard error) of mature (biologically active) TGF-beta 2 in the aqueous humor of eyes with POAG was 293.6 +/- 33.6 pg/ml, significantly higher than that in eyes with PACG, EXS and SG: 147.5 +/- 28.1, 135.8 +/- 30.2 and 41.0 +/- 10.7 pg/ml, respectively (P = 0.0006, P = 0.0010 and P = 0.0003; analysis of variance). The mean concentration (+/- standard error) of total TGF-beta 2 in the aqueous humor of eyes with POAG was 1647.6 +/- 124.5 pg/ml, not significantly different from that in eyes with PACG, EXS and SG: 1482.9 +/- 148.2, 1442.7 +/- 187.8 and 1929.0 +/- 367.6 pg/ml, respectively. A multivariate analysis using logistic regression showed significant correlations between mature TGF-beta 2 concentration and history of cataract surgery (P = 0.0225) and the use of carbonic anhydrase inhibitors (P = 0.0143).

CONCLUSIONS

Our results indicate that increased levels of TGF-beta 2 may play an important role in the pathogenesis of POAG.

Chemical analysis of transuranium nuclides in the uranium solution of the JCO criticality accident

Atom numbers of 239Np and 239Pu, which had been produced by the neutron capture reaction of 238U in the uranium solution of the JCO criticality accident at Tokai-mura, Japan, were determined precisely by a radiochemical method. It was found that the measured atom ratio of 239Np/239Pu at termination of the criticality depends sensitively on the history of the neutron capture reaction during the accident (about 20-hours continuance). The history was evaluated by comparing the measured value and those calculated by a burnup calculation code. The percentage of the number of the neutron capture reaction at the initial stage of the criticality during 25 min against the total events was determined to be 24±6%.

Terson syndrome caused by ventricular hemorrhage associated with moyamoya disease--case report

A 24-year-old female presented with Terson syndrome secondary to bilateral ventricular hemorrhage as a complication of moyamoya disease. Ophthalmoscopy and magnetic resonance imaging clearly demonstrated vitreous hemorrhage in the left eye globe. Various visual symptoms are associated with moyamoya disease, almost all of which result from ischemic lesions in the visual cortex and optic pathways. In this case, the visual disturbance was caused by Terson syndrome secondary to ventricular hemorrhage. Close ophthalmological and radiological evaluation is mandatory even in patients with moyamoya disease and hemorrhagic manifestation located in the intracerebral, subarachnoid, or intraventricular space.

Suppression of insulitis and diabetes in B cell-deficient mice treated with streptozocin: B cells are essential for the TCR clonotype spreading of islet-infiltrating T cells

In order to clarify the role of B cells in the development of insulitis and diabetes, B cell-deficient (B(-)) mice treated with streptozocin (STZ) were studied. The extent of insulitis and the cumulative incidence of diabetes were significantly suppressed in B(-) mice (P < 0.0001), indicating that B cells are crucial for the progression of insulitis and diabetes. Accumulation of both CD4(+) T cells and B cells was observed in islets of B(+) mice, while CD4(+) T cells but not B cells were found in B(-) mice. A few CD8(+) T cells and macrophages were detectable in both types of mice. The immunohistochemical study did not reveal any change in the subpopulations of infiltrating lymphocytes except for the absence of B cells in the B(-) mice. TCR V(beta) gene repertoire usage of islet-infiltrating T cells was restricted to some extent in the B(+) or B(-) mice, but there was no significant difference between the B(+) and B(-) mice, suggesting that the initial islet-reactive T cell response can occur in the absence of B cells. In contrast, TCR clonotype spreading of islet-infiltrating T cells was significantly suppressed in B(-) mice compared with B(+) mice (P < 0.0001). These data suggest that initial priming of T cells is not impaired and TCR V(beta) repertoire usage is not limited by the lack of B cells, while B cells are important essentially for the spreading of islet-infiltrating clonal T cells in autoimmune diabetic mice induced with STZ.

Establishment of an embryonic stem (ES) cell line derived from a non-obese diabetic (NOD) mouse: in vivo differentiation into lymphocytes and potential for germ line transmission

A non-obese diabetic (NOD) mouse-derived embryonic stem (ES) cell line has been stably maintained in an undifferentiated state with a characteristic ES cell-like morphology, expressing the stem cell marker alkaline phosphatase, and displaying a normal diploid karyotype. After injecting the NOD-ES cells into blastocysts, chimeric mice were obtained. Small but significant numbers of lymphocytes expressed the NOD-derived MHC allele. When a chimeric mouse was mated with C57BL/6 mice, an agouti mouse was obtained, having the NOD-derived H-2 I-A(beta)g7 haplotype. Thus, an NOD-ES cell line which can differentiate into lymphocytes with potential for germ line transmission was successfully established.

Lyn-mediated down-regulation of B cell antigen receptor signaling: inhibition of protein kinase C activation by Lyn in a kinase-independent fashion

Stimulation of the B cell Ag receptor (BCR) induces activation of tyrosine kinases such as Lyn and Syk, phosphorylation and activation of multiple signaling components, and eventually, the expression of several genes including c-myc. Syk is required for activation of phospholipase C-gamma 2 and the subsequent phosphatidylinositol hydrolysis, leading to protein kinase C (PKC) activation and intracellular Ca2+ increase. In contrast, the function of Lyn remains obscure. Here, we report that BCR-mediated induction of c-myc promoter activity and of PKC activity, but not the expression level of functional PKC, was markedly augmented in Lyn-deficient chicken B cells. This enhancement was reversed to the level of wild-type cells by the expression of exogenous Lyn of kinase-inactive form. These results indicate that Lyn inhibits BCR-mediated activation of a large portion of PKC isozymes in a kinase-independent fashion. This finding reveals a novel role of Lyn in negative regulation of BCR signaling.

Task-related coherence and task-related spectral power changes during sequential finger movements

In order to investigate the activity of cortical regions in the control of complex movements, we studied task-related coherence (TRCoh) and task-related spectral power (TRPow) changes in 8 right-handed subjects during the execution of 4 different finger movement sequences of increasing complexity. All sequences were performed with the right hand and were paced by a metronome at 2 Hz. EEG power spectra and coherence values were computed within alpha (8-12 Hz) and beta (13-20 Hz) frequency bands for 29 scalp EEG positions during the execution of the sequences and were compared with values obtained during a rest (control) condition. Movement sequences were associated with TRPow decreases in the alpha and beta frequency bands over bilateral sensorimotor and parietal areas, with a preponderance over the contralateral hemisphere. Increases of TRCoh occurred over bilateral frontocentral regions. TRCoh decreases were present over the temporal and occipital areas. The spatial extent and the magnitude of TRPow decreases and TRCoh increases in both frequency bands were greater for sequential movements of higher complexity than for simpler ones. These results are consistent with previous findings of bilateral activation of sensorimotor areas during sequential finger movements. Moreover, the present results indicate an active intercommunication between bilateral and mesial central and prefrontal regions which becomes more intense with more complex sequential movements.

Establishment of tissue culture cell strains from normal fetal human liver and kidney

Three cells strains of tissue culture were established from normal fetal human liver and kidney tissues. The rate of cell proliferation decreased with time after the primary culture. The cells were rarely subcultured, but the medium was renewed routinely twice a week. After 9 months of cultivation, the cells were found in both tissues to have abruptly begun to proliferate rapidly, but only in the group culture in the medium containing galactose and sodium pyruvate in place of glucose. No special treatment were given to these cultures, e.g. treatment with viruses, chemical carcinogens and others. The chromosome number was kept around diploid in the beginning but was shifted to hypotriploid after the establishment. The cell strain from liver consists of epithelial cells. The cell strains from kidney consist of mixed population of various kinds of cells. Doubling time of cells is about 33.4 hours in all of them, as determined by cinemicrography. This might be the first establishment of cell strains from untreated, normal human tissues.

An attempt in tissue culture at preventing and treating the collagen fiber formation of liver cells

To prevent and to cure liver cirrhosis, we examined the effect of the ethanol extract of berries of Japanese ampelopsis on the collagen formation of rat liver cells in tissue culture. These cells had been transformed to produce collagen fibers very actively. When added at a time of subcultivation, the extract prevented the formation of collagen fibers. When it was added after the formation of collagen fibers, the fibers were fragmented into fine microfilaments.

Neutralization of cytotoxicity of spermine on the proliferation of rat liver cells in tissue culture

Cytotoxicity of spermine in tissue culture was found previously. To neutralize this toxicity, the addition of various high molecular weight substances and others was attempted in this paper, e.g. lysozyme, N-acetyl-D-glucosamine, chondroitin sulfate, poly-L-glutamic acid, bovine serum fractions V and VI, fetal calf serum, methyl cellulose, carboxymethyl cellulose, polyvinylpyrrolidone and others. Into the culture of rat liver cells, strain RLC-10(2), simultaneous addition of other substances with spermine did not neutralize the toxicity. However, by the pretreatment of spermine with fetal calf serum or bovine serum albumin (fraction V) at 37 degrees C for 24 hr, the toxicity of spermine was markedly reduced. This was probably due to the denaturation of spermine caused by the pretreatment.

Tapping culture--an improved method for cell suspension culture

A new culture vessel was designed for cell suspension culture. A silicone-covered magnet bar fixed by one end to the side wall of the bottle was held horizontally a short distance from the bottom. A standard type magnetic stirrer was used. In contrast to the conventional horizontal movement of "stirring" in cultures the bar moves vertically with a "tapping" motion. This improvement resulted in less cell injury, higher rate of cell proliferation and formation of fewer bubbles than in the conventional type. Nine cell types were simultaneously cultivated in tapping, stirring and stationary culture. All cell types proliferated more luxuriously in tapping cultures then in stirring cultures. Serial cultivation of cells in tapping cultures was also successful.

Carcinogenesis in tissue culture 30: malignant transformation of normal rat liver cells treated with diethylnitrosamine in tissue culture with special reference to the differential effects of cytochalasin B on various cells with and without tumorigenicity

Liver tissue of a suckling rat was cultured. After 3 weeks of cultivation, the cultures consisting of epithelial cells were treated with 50 micrograms/ml or 100 micrograms/ml DEN for 7 days. 5 months after the treatment, the mode of chromosome number was found decreased from 42 to 40 in the 100 micrograms/ml DEN-treated group and shifted to triploid range after 21 months. The mode in the 50 micrograms/ml DEN-treated group maintained the diploid number until the 5th month but was found reduced to 40 in 21 months. On subcutaneous backtransplantation into young rats at the 22nd month, the treated cells produced tumors at the site inoculated in all the rats. Metastatic foci were also detected in lungs. These tumors were histologically diagnosed as hepatomas. Untreated control cells did not produce tumors. The differential effects of cytochalasine B on the cells with and without tumorigenicity were examined by the use of these cells and other cells, and it revealed that the capacity of multinucleated cell-formation by cytochalasin B fairly corresponds with the backtransplantability of the cells. Binucleated cell formation, not more than 2 nuclei, in the culture of normal cells was found by time-lapse cinemicrography to be not due to the non-capacity of multinucleation but to the destruction of multinucleated cells.

Pedigree analysis of the hypothermal recovery of the effects of gamma-rays on hepatoma cells

Cultured hepatoma cells of the rat were irradiated with 400 to 900 R of gamma-rays. They were kept at room temperature for several hours before transferred to normal culture condition at 37 degrees C. The pedigree analysis of growing cells recorded by cinematography indicated a variety of lethal and non-lethal recovery events such as a decrease in lethal branch formation and an increase in locomotion. The so-called repair immediately after irradiation has many facets depending upon dose and duration of the low temperature treatment.

Establishment of epithelial cell lines from rat glandular stomachs

Nine epithelial cell lines were isolated from glandular stomach cells of fetal and suckling JAR-2 rats after the elimination of mesenchymal cells by mechanical and colonial isolation methods. Those cells have been proliferating continuously in a typical pavement-like arrangement. In early cultures a part of focal monolayers of small epithelial cells died simultaneously ("contact death"). The cells of three lines (RGS-2,RGS-5 and RGS-8) formed hemicysts when incubated for several weeks without subcultivation. Addition of But2cAMP and theophilline into culture medium enhanced the hemicyst formation by RGS-8 cells. Some evidence suggested that those three lines were originated from mucous epithelium of rat glandular stomach. These epithelial cell lines would be useful in the study of chemical carcinogenesis in culture.

Kinetics of microcolonies of cultured mammalian cells after bleomycin treatment

Cultured ascites hepatoma cells of the rat were treated with 400 to 900 R of gamma rays or 25 to 100 mug/ml of bleomycin for 30 min. The cells were followed up for 133 hr and the pedigrees were analyzed. Gamma rays and 2 low doses of bleomycin gave rise to typical reproductive death in generations 1 and 2 but 100 mug of the drug produced frequent interphase death. Natural death and induced death did not follow statistical randomness suggesting an existence of weak and sensitive clones in a population.

Carcinogenesis in tissue culture 26: malignant transformation of rat liver cells in vitro associated with paradoxical electrokinetic changes

Periodical examinations of the electrophoretic mobility of rat liver cells of two culture strains, RLC-10(2) and JTC-25.P3, were performed after the treatment with 3.3 X 10(-6) M 4-nitroquinoline 1-oxide (4NQO) for 30 min in culture. As early as 47th day after a single treatment with 4NQO, both control and treated cells of RLC-10(2) were found to produce tumors in animals on back-transplantation. At this stage, however, little difference was yet observed in electrokinetic patterns between the treated cells and the original antecedent cells. In contrast, a subline, JTC-25.P3, treated twice with 4NQO under the same conditions demonstrated a malignant electrokinetic pattern resembling that of rat ascites hepatocarcinoma strains, although its tumorigenicity was not verified. These discrepancies between changes of electrokinetic pattern and tumorigenicity were discussed with special references to the antigenic difference between cultured cell strains and each original host rats.

Carcinogenesis in tissue culture 27: heterotransplantation as an alternative in vivo assay for neoplastic state of cells in culture

Cells of serially cultured strains and newly-isolated cells originating from rat liver and lung were heterotransplanted into pouches of golden hamsters treated with antithymocyte serum (ATS). The "take" was determined by histopathological examination of nodules formed by 3 weeks after the transplantation. The results obtained under this criteria showed that 9 of 11 cell strains backtransplantable to rats and 2 of 4 strains untransplantable were in parallel with those in rats. Three kinds of uncultured liver cells resulted in "no take".

Kinetics of microcolonies of cultured mammalian cells after gamma irradiation

The time of cell destruction was determined by pedigree analysis before macrocolony formation immediately after irradiation of gamma rays (400-900 R) in cultured rat hepatoma cells. Cell destruction occurred and was distributed to various generations in proportion to dose. The loss of reproductive integrity resulting in an extinction of a clone was limited in earlier generations, 0 to 2, but the loss of reproductive capacity was observed in later generations. It seems probable that two types of loss of reproduction come from random transmission of lethal signals produced in parent cells irrespective of the pattern of pedigrees.

Isolation and characterization of alkaline phosphatase-constitutive variants from Chinese hamster ovary cells (CHO-k1)

Pure clones with high alkaline phosphatase (ALP) activity were isolated from Chinese hamster ovary (CHO-K1) cells which showed no detectable ALP activity. ALP-positive cells appeared at the frequency of 10(-4) in the N-methyl-N'-nitrosoguanidine-treated cell population. With respect for cellular morphology, plating efficiency and several other enzymatic activities, no distinct difference was found between the original CHO-K1 cells and its ALP-positive variants, although some alterations in karyotype were found. Levels of ALP activity in these clones was stably maintained during serial cultivation. Some of the enzymological properties of ALP in the isolated clones were similar to those in bone or kidney.

Effects of polyamines on the proliferation of mammalian cells in tissue culture

Spermine, spermidine, putrescine and agmatine were examined for their cytotoxicity to mammalian cells in tissue culture. Spermine exhibited the highest cytotoxicity among them. It was followed by spermidine. Putrescine and agmatine showed little toxicity but rather acceleration of cell proliferation in some concentrations. Among 16 kinds of rat cells and strains and a mouse cell strain examined, liver cells, fibroblasts, and cells serially grown in a protein-free synthetic medium were sensitive to spermine in the order described. Normal liver cells were more sensitive than hepatoma cells, and normal fibroblasts were also more sensitive than sarcoma cells. Bovine serum albumin fraction markedly accelerated the cytotoxicity of spermine.

A simple method for the cultivation of rat liver cells

A simple method to culture rat liver parenchymal cells is described. Minced liver tissues were dissociated with no pre-perfusion by a newly developed enzyme, bacterial neutral proteinase, and cultured in the medium consisting of 10% fetal calf serum and 90% of a new synthetic medium, DM-153. By the adequate technique of primary dissociation and first subcultivation, parenchymal cells were selected. Cultivation in arginine-free medium was also useful in selecting them. The cultured cells exhibited activities of certain enzymes similar to those of liver cells in vivo. Cell strains have been successively established from liver tissues of embryo, suckling and adult rats. Liver cells, however, cultured in this way, can also be used for experiments in the early stage of serial cultivation.

Interaction in culture between mouse ascites hepatoma (MH-134) cells and lymphoid cells of isologous mice

Thymocytes or lymphocytes of mesenteric lymph nodes were obtained from mice bearing subcutaneously mouse ascites hepatoma MH-134 for 5 to 40 days. These lymphoid cells were added into the cultures of MH-134 cells. Morphological changes of cells in the mixed cultures were observed by time-lapse cinemicrography for the period of 4 weeks. Lymphoid cells were phagocytosed by MH-134 cells, and, in most cases, the tumor cells did not undergo any damage due to the phagocytosis. The exceptional cases were as follows: When MH-134 cells were mixed with thymocytes from mice bearing MH-134 tumor for 5 days, MH-134 cells phagocytosed thymocytes but some of them died later. In the mixed cultures of MH-134 cells and thymocytes or mesenteric lymph node lymphocytes from mice bearing MH-134 for 14 or 15 days, MH-134 cells phagocytosed lymphoid cells but died later by the burst of cytoplasm. By the burst many lymphoid cells phagocytosed appeared from the broken cytoplasm of MH-134 cells and, in some cases, the lymphoid cells looked to be alive. These findings suggest the possibility that lymphoid cells attack tumor cells not only from the cell surface but also from the inside being phagocytosed by tumor cells.

Carcinogenesis in tissue culture 24: tumorigenicity and aggregate-forming capacity of mammalian cells in culture

Twenty two kinds of strains and substrains of mammalian cells were cultivated on a gyratory shaker to obtain cell aggregates. The relationship between the morphology of aggregates and tumorigenicity of the cells was investigated. In some groups of cells, the size of aggregates corresponded with their tumorigenicity, e.g. among rat liver cells untreated, hepatoma cells produced by back-transplantation of rat liver cells after the treatment with a chemical carcinogen in tissue culture, and the hepatoma cells passaged serially through rats. The correspondence, however, was generalized to not all the cell strains. It was impossible to identify the tumorigenicity of cells by their aggregate-forming capacity.

Interaction in culture between mouse ascites mammary carcinoma (MM2) cells and lymphoid cells of isologous mice

MM2 cells, ascitic tumor originated from spontaneous mammary carcinoma of C3H/He mouse, were mix-cultured with lymphoid cells of thymus or mesenteric lymph nodes from isologous animals of the same sex. The interaction in culture between these cells was examined by time-lapse cinemicrography. In single culture, thymocytes, mesenteric lymph node lymphocytes and MM2 cells were kept for 7 days with little change in cell population. Lymphocytes of both sources showed a marked decrease in cell number when cultured together with MM2 cells, being evidently phagocytosed by MM2 cells. Lymphocytes from MM2-bearing mice or mice sensitized with deoxycholate-extracted MM2 antigen were also all phagocytosed. MM2 cells exhibited no sign of damage or degeneration due to the phagocytosis. Thymocytes were not phagocytosed by histiocytes obtained from ascitic fluid 3 days after i.p. injection of 5% starch suspension. Phagocytosis of erythrocytes or lymphoid cells from spleen by MM2 cells was not detected.

Proliferation of mouse ascites mammary carcinoma MM2 cells in the primary culture

Culture conditions suitable for active proliferation in primary culture of transplantable mouse ascites mammary carcinoma MM2 cells were investigated; kind of serum, its optimal concentration, composition of medium, inoculum size of cells, addition of ascites, conditioned medium or hormones, and others. The most active growth was obtained in the medium consisting of 5% fetal calf serum and 95% RPMI-1640, so far as examined. The addition of 1 mug/ml of estriol more accelerated the proliferation. MM2 cells were found to have preserved their tumorigenicity after 5 months of cultivation.

An improved synthetic medium suitable for tissue culture of various mammalian cells

A new mixture of synthetic medium, DM-153, was designed to obtain a higher rate of proliferation of various cells and to be adoptable for both of closed and opened systems of culture. The activity was compared to that of other synthetic media by cultivation for 2 weeks. In the presence of 10% (v/v) fetal calf serum, DM-153 exhibited the highest rate of proliferation of rat liver cells, strain RLC-10(2), than did Eagle MEM, DM-145 or lactalbumin hydrolysate which had been employed as a routine growth medium for the cells. In the absence of any high molecular weight substances in the medium, both of DM-153 and DM-145 showed higher rate of proliferation of rat liver cells, strain JTC-25-P3, than that obtained by MEM. In the case of primary culture of human blood lymphoid cells supplemented with 10% fetal calf serum, DM-153 resulted in apparently higher rate of cell survival than did RPMI-1640. The mixture DM-153 was confirmed to be suitable as a multi-purpose synthetic medium.