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J G Sharp

Publications and source records attributed to J G Sharp.

At least 91 records · Page 5Linked to original sources
PubMed1988

Effects of differentiation inducing chemicals on in vivo malignancy and NK susceptibility of metastatic lymphoma cells.

In the present investigation we have determined the effects of the differentiation-inducing chemicals dimethyl sulfoxide (DMSO) and sodium butyrate on the growth and tumorigenicity of a highly malignant/metastatic cell line (RAW117-H10) and its less tumorigenic parental lymphoma cell line (RAW117-P). Both of these agents at doses shown to be nontoxic slowed the growth of these cells in suspension culture and significantly lengthened the doubling time while reducing colony formation in the agar tumor stem cell assay. Corresponding to these observations, the in vivo tumorigenicity of the highly malignant RAW117-H10 line was reduced by both chemicals but particularly by butyrate treatment. In addition, both agents increased the expression of some glycoproteins and the glycolipid asialo GM1. There was also a corresponding increase in the NK susceptibility of the normally NK resistant RAW117-H10 cells. To determine if the decreased malignancy of the highly malignant cells following treatment with the chemical agents was primarily due to the alteration in cell surface glycoconjugates or merely due to concomitant decreased growth potential, we transplanted highly glycosylated membrane fragments from normal syngeneic thymocytes to both RAW117-P and RAW117-H10 cells using a Sendai virus mediated membrane fusion technique. The in vivo tumorigenicity of the membrane altered RAW117-H10 cells was significantly decreased. These results strongly suggest that the decreased in vivo malignancy of RAW117-H10 cells resulting from treatment with chemical differentiation agents is caused by their increased susceptibility to NK cell mediated lysis which in turn results from cell surface changes involving altered, primarily increased, expression of certain glycosylated surface molecules. The cell surface glycoconjugates, such as receptors for certain lectins and glycolipid asialo GM1, can be used as markers for malignant potential and NK sensitivity of malignant lymphoid cells.

Animals↗
PubMed1987

Cell surface properties associated with malignancy of metastatic large cell lymphoma cells.

The highly malignant and metastatic RAW117-H10 cell line was developed by in vivo selection from the Abelson leukemia virus induced parental RAW117-P lymphoma. In this study we have characterized these cell lines with regard to their expression of lymphocyte and macrophage differentiation antigens, adherence, phagocytic properties, binding of various lectins, binding of antibodies to glycolipid asialo-monoganglioside, and the role of butanol extractable cell surface molecules to determine if any of these cell surface properties are associated with the malignant potential of RAW117-H10 cells. The only major difference in immunological phenotypes between RAW117-P and RAW117-H10 cells was an increased expression of Thy-1 molecules by the latter. However, the highly malignant RAW117-H10 cells bound significantly less concanavalin A, Ricinia communis agglutinin, succinylated wheat germ agglutinin, and particularly anti-asialomonoganglioside than their parental counterpart and were resistant to natural killer cell mediated cytolysis. Removal of butanol extractable cell surface molecules significantly decreased the malignancy of RAW117-H10 cells and increased their susceptibility to natural killer cell mediated cytolysis. The butanol treated RAW117-H10 cells regained high in vivo malignancy when recultured for 3 days to permit regeneration of their cell surface components. The butanol extracted RAW117-H10 cells still expressed high levels of Thy-1 indicating that this most probably represented "inappropriate" antigen expression. Since the expression of lymphocyte differentiation antigens did not correlate with the malignant behavior of the cells, we postulate that these antigenic differences merely represent phenotypic variation. The decreased malignant potential of the butanol treated RAW117-H10 cells did correlate with increased cell surface anti-asialomonoganglioside binding (glycolipid) and increased natural killer cell susceptibility.

Animals↗
PubMed1987

Stimulation of neomucosal growth by systemic urogastrone.

Patching small intestinal defects with colon serosa results in the growth of functional neomucosa. However, the rate of neomucosal growth is slow and the defect contracts markedly. The aim of this study was to determine if systemic urogastrone would enhance neomucosal growth. Twenty-two New Zealand white rabbits had two 2 X 5-cm ileal defects patched with colon serosa and osmotic pumps placed subcutaneously. Eleven animals had saline infused at a rate of 5 microliter/hr. The other eleven rabbits had urogastrone (1 mg/ml saline) infused at the same rate. One animal died in this group. There was a modest increase in neomucosal growth after 2 weeks of urogastrone infusion. Three weeks after patching, defect coverage was significantly greater in the urogastrone group (99.8 +/- 0.1 vs 96.0 +/- 1.2%, P less than 0.005) and more defects were completely covered by neomucosa (6/10 vs 1/12, P less than 0.05). Less contraction occurred in the urogastrone group (46 +/- 2 vs 35 +/- 3% initial defect, P less than 0.005) and resultant neomucosal surface area was greater (361 +/- 12 vs 266 +/- 20 mm2, P less than 0.0005). In vitro glucose uptake was significantly greater in the urogastrone group but disaccharidase and diamine oxidase activity were similar. Crypt cell production rate was significantly greater 2 weeks after operation compared to 3 weeks in both groups and was greater in the urogastrone group compared to the saline group at 2 weeks (24.9 +/- 1.1 vs 20.1 +/- 1.1, P less than 0.02). Systemic urogastrone enhances neomucosal growth by increasing the rate of growth and diminishing contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Amine Oxidase (Copper-Containing)↗
PubMed1987

Differential growth characteristics of low and high metastatic variant RAW117 murine lymphosarcoma cells.

The Abelson-virus-induced murine lymphosarcoma cell line RAW117-P and its in vivo selected highly malignant and metastatic variant RAW117-H10 have been studied for their growth in vivo, in vitro and in semi-solid agar. The highly malignant metastatic variant RAW117-H10 cells killed syngeneic Balb/c mice rapidly and formed 100-200 times more gross liver tumor nodules than the less malignant parental RAW117-P cells. On the other hand, there were no differences between the in vitro growth kinetics of these cells as measured by various parameters such as metaphase arrest or cells in DNA synthetic phase on various days after the initiation of the culture. These cells could be grown in semi-solid agar and formed characteristic colonies. The parental cells formed many very small colonies, whereas the highly malignant cells formed fewer, but very large colonies in soft agar. These results suggest that differential interactions of highly malignant RAW117-H10 cells with the host, particularly the host immune system, are much more important for regulating the number of metastases than any intrinsic growth advantages. It appears that growth differences, potentially based on lack of response to feedback inhibition rather than on kinetic parameters, are responsible for highly malignant RAW117-H10 cells forming larger colonies both in agar in vitro and in the liver in vivo.

Animals↗
PubMed1987

Detection of malignant cells in histologically normal bone marrow using culture techniques.

Cellular material retained on screens used to filter aspirated bone marrow for future autologous marrow transplantation was studied using long-term culture techniques in 20 consecutive patients. All patients had marrow aspirate and biopsy specimens that were normal histologically. Cultures from five patients grew malignant cells similar to those of the known underlying malignancy. Two types of culture methods were used in these studies. Method I consisted of a long-term bone marrow culture system which predominantly favors adherent cells, and Method II consisted of a suspension type culture system favoring expansion of mononuclear cell types. These findings suggest that tumor cells are reinfused more often at the time of autologous bone marrow transplantation than has been previously suspected. Although the clinical significance of these findings is not known, it is clear that culture techniques combined with special stains and molecular probing will allow the improved detection of occult tumor cells in bone marrow from patients undergoing autologous marrow transplantation. These observations emphasize the need for a comprehensive study of histologically normal autologous marrow using culture techniques to determine the frequency of occult involvement by viable malignant cells and the clinical implications of these findings.

Adult↗
PubMed1987

Stem and stromal cell reconstitution of lethally irradiated mice following transplantation of hematopoietic tissue from donors of various ages.

If the limited life span of hematopoietic tissues in vitro is due to a finite proliferative capacity of individual stem cells, one might expect tissues of young donors to possess a greater proliferative capacity and to contain a larger population of primitive stem cells than those of older donors. To test this hypothesis, we used 12- and 8-day spleen colony formation (CFU-s) to assay more and less primitive stem cell subpopulations of three murine hematopoietic tissues: fetal liver (FL) and weanling (WBM) and adult (ABM) bone marrow. Subsequently, the same assays and a stromal cell assay were performed on the bone marrow from groups of lethally irradiated mice reconstituted with these tissues. Comparison of the CFU-s content of the donor tissues revealed that FL contained a significantly greater proportion of primitive stem cells as evidenced by a (Day 12):(Day 8) CFU-s ratio of 3.0 +/- 1.0 as compared to 0.9 +/- 0.1 for WBM and ABM. In addition, at 21 weeks post-transplantation the CFU-s/femur values of the FL reconstituted group were significantly greater than those of the ABM and WBM reconstituted groups. These results suggest that fetal hematopoietic tissue contains a greater proportion of primitive stem cells and has a greater proliferative potential than hematopoietic tissue from older donors. No differences were seen in stromal cell reconstitution of the three experimental groups. In all cases, assayable fibroblast colony forming cells (CFU-f) remained at 20-40% of control values, even at 21 weeks postreconstitution.

Aging↗
PubMed1987

Ontogeny and regulation of the immune system.

Classic studies in embryology and contemporary research in immunology and molecular biology have disclosed the carefully orchestrated events leading to development of the immune system and immunoregulation that ultimately provide immunohomeostasis. During ontogeny, the pluripotential stem cell emerges and differentiates into all hematopoietic lineages, including three major immunologically relevant components: T-cell differentiation occurs within the thymus; B cells appear within fetal liver, adult bone marrow, and possibly other abdominal sites; and concurrently, the monocyte-macrophage system develops. Under the influence of an array of cytokines and cellular interactions, immune regulation is established. T and B lymphocytes elaborate genetically encoded messages that acquire specificity via transposable genetic elements. Receptors and cytokines provide immune recognition, communication, regulation, and memory for antigens. Inherited and acquired defects in ontogeny and immune regulation are the basis for immunodeficiency disorders.

Animals↗
PubMed1985

Comparison of the intravenous and intraperitoneal routes of administration of tritiated thymidine in studies of cell production in the gastrointestinal tract of the rat.

Incorporation of 3H-Thymidine into DNA-synthesizing cells of the gastrointestinal tract of the rat was examined following administration of the isotope by intraperitoneal and intravenous routes. Estimates of whole tissue incorporation expressed as DPM/mg dry weight and of proliferating cells expressed as DPM/crypt or gland in the different segments of the gut indicated no differences in the degree of 3H-TdR uptake into DNA following intraperitoneal or intravenous routes of administration. The possibility of misdirected I.P. injections was examined following injection of 3H-TdR into the cecum or bladder. DPM/mg wet weight of gastrointestinal tissues indicated reduction in the uptake of 3H-TdR into DNA of intestinal tissues following intracecal and intrabladder administration of 3H-Tdr. The intraperitoneal route of administration of 3H-TdR appears to be equally effective in the distribution of the isotope into different segments of the gut when compared to the intravenous route and is a more convenient method in studies of cell production in the gastrointestinal tract of the rat.

Animals↗
PubMed1985

Late ultrastructural effects of heavy ions and gamma irradiation in the gastrointestinal tract of the mouse.

The irradiated gastrointestinal tract of LAF1 mice was examined one year following a single dose (1000 rad) of either 12C heavy ions or 60Co gamma rays. Qualitative ultrastructural analysis of the gastrointestinal tract of mice exposed to heavy ions or gamma irradiation did not show any discernible differences. In the stomach of irradiated mice, parietal cells contained numerous lysosomes; the gastric chief cells occasionally contained myelin figures. The epithelial cells of the small intestine, especially jejunum and ileum, showed several changes: (1) increased vacuolation was seen both inter- and intra-cellularly, (2) epithelial cell projections penetrated the basal lamina and were in contact with underlying mesenchymal cells, (3) occasional Paneth cells contained intracellular vacuoles consisting of fibrillar and granular material. In the large intestine occasional signs of degeneration were observed. Qualitative analysis of stromal elements of the gut in irradiated mice indicated the presence of damage to capillary endothelial cells, smooth muscle cells and some nerve processes. The amount of basement membrane (BM) around capillaries and small vessels was increased; the same phenomenon was observed to affect the nerve processes, but with less severity. Quantitative analysis of the basement membrane thickness around capillaries in irradiated vs. control mice showed significant differences. Basement membrane thickness around capillaries in the gastric mucosa and duodenum did not differ significantly in any of the treatment groups. In jejunum, the gamma treated animals exhibited significantly higher BM thickness when compared to unirradiated controls. In ileum, only 12C-heavy ion treated animals showed thicker BM when compared to their respective controls. In colon, both 12C- and 60Co-treated animals showed increased BM thickness when compared to controls.

Animals↗
PubMed1985

Thymic non-lymphoid cells.

In formulating this summary of our simon-pure knowledge of the structure/function relationships in the thymus, we decided that the time may have come to introduce a suitable dose of cynicism to balance the sometimes hopeless optimism of the past. Are the non-lymphoid cells of the thymus necessary for thymic function? Probably, but not to the extent or uniqueness that some authors including ourselves have previously claimed; T cells can probably differentiate in other tissues but may acquire their preference for MHC class II in the thymus. Mouse thymic lymphoid cell traffic and surface phenotype has recently been summarized pictorally by Scollay and Shortman [95]. Briefly stated, within the thymus, cells are hatched, matched and then dispatched. Minimally, the non-lymphoid cells act either as scenically varied obstacles along the way, nurseries for newborn T cells, or as tombstones for life's disenfranchized, effete and autoaggressive thymocytes. Hassall's corpuscles are morphological structures unique to the thymus, which are most useful to medical students for identification of this tissue. Their function remains one of life's great mysteries. Morphologically, they are suitable companions to the more recently described strange multicellular complexes of lymphocytes and epithelial cells which might be functionally important. The thymus of the much studied inbred, environmentally mollycoddled, laboratory mouse has been often and majestically described. It is probably typical for that of man and most mammals. It may, however, be unrepresentative of the thymus of stressed and parasitized wild animals. Diseases of the thymus generally can be categorized as not having enough thymus, having a neoplastic thymus or having a thymus which does not work properly. The bottom line in our knowledge of thymic nonlymphoid cells is that if you are born without them, you get sick and die; unless, of course, you are a nude mouse in Omaha, in which case you just freeze to death.

Animals↗
PubMed1985

Differentiation inducing effects of butyrate and DMSO on human intestinal tumor cell lines in culture.

In the present report, we have studied the effects of butyrate and dimethyl sulfoxide (DMSO) on the characteristics of four human intestinal tumor cell lines in vitro; namely a duodenal adenocarcinoma HTB-40 and three adenocarcinomas of colon: HT-29, CCL-218, and CCL-222. In the presence of concentrations of 2 mM butyrate and 2% DMSO the growth of all these four cell lines was significantly inhibited. Both these agents lengthened the doubling time of these cell lines by about twofold. In addition, the morphology of the treated cells was altered. All four cell lines grow in semisolid agar and form characteristic colonies. Butyrate and DMSO inhibited the colony forming efficiency of these cell lines by 40-60%. Using flow cytometric analysis, the cells that were grown in the presence of butyrate and DMSO were analyzed for their lectin-binding properties. For this purpose the lectins used were concanavalin-A (Con-A), peanut agglutinin (PNA), wheat germ agglutinin (WGA), and succinylated wheat germ agglutinin (SWGA). All four cell lines showed an increase in lectin-binding cells. CCL-218, which showed no PNA binding when grown without these agents, acquired about 25% reactivity when grown in the presence of butyrate or DMSO. All these cell lines showed an increase in the percentage of positive cells for the lectin SWGA that unlike WGA does not bind to sialic acid on the cell surface, suggesting an increase in nonsialated residues on all the treated cells. These results indicate a differentiation inducing effect of butyrate and DMSO on these cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Butyrates↗
PubMed1984

A decrease in thymus-mediated immune responses as a result of treatment of neonatal rats with glutamate.

We investigated whether administration of monosodium 1-glutamate (MSG) to neonatal rats would disrupt immune responses in intact and orchidectomized adult male rats. Neonatal male rats were treated with saline or MSG which causes severe endocrine abnormalities. Half of each group of animals were orchidectomized as adults and killed one week later along with intact rats. MSG treatment resulted in suppressed serum LH levels in intact rats. Thymus weight and spleen cellularity in intact animals were not affected by MSG treatment, but thymus weight increased within one week after orchidectomy in both saline- and MSG-treated groups. In intact rats, lymphocyte stimulation by the T cell specific mitogens (concanavalin A or phytohemagglutinin) or the B cell specific mitogen (lipopolysaccharide) was unaffected by prior treatment with MSG. However, MSG treatment blocked the decrease attributable to orchidectomy in concanavalin A and phytohemagglutinin stimulation of lymphocyte blastogenesis. The results suggest that administration of MSG to neonatal male rats can alter some immune responses in the adult animal.

Animals↗
PubMed1984

Comparison of tritiated thymidine and metaphase arrest techniques of measuring cell production in rat intestine.

Measurements of intestinal cell production at several sites throughout the gastrointestinal tract were compared using two different methods, namely tritiated thymidine to determine the uptake of tritium per unit weight of tissue (dpm/mg) and per microdissected intestinal crypt or stomach gland (dpm/crypt or gland) and the metaphase arrest technique, in the same group of rats. The metaphase arrest technique was employed to determine the crypt cell production rate per hour (CCPR). The dpm/crypt or gland of tritiated thymidine-derived tritium in microdissected intestinal crypts or stomach glands showed a good linear correlation (r = 0.93) with CCPR which extrapolated through the origin. The dpm/mg wet weight of tissue showed a good linear correlation with CCPR (r = 0.87) and dpm/crypt (r = 0.97); however, neither of these relationships extrapolated through the origin. Instead there was a positive intercept of dpm/mg tissue which represented about 25-30% of the maximal tritium content of the intestine. This radioactivity in tissue had no counterpart in the crypts or glands and presumably reflected unbound tritium and tritium in cells which were located outside the epithelial compartment. The good linear correlation (r = 0.93) between dpm/crypt and CCPR extended to the intestine of transected and 75% small bowel resected rats. Subsequent analysis of the times recorded for these procedures showed that determination of CCPR was faster by at least 25% than measurement of dpm/crypt. In conclusion, dpm/crypt but not dpm/mg tissue gave a valid estimate of intestinal cell production equivalent to measurement of CCPR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Comparison of single time point and linear regression estimates of cell production in rat intestinal crypts after perturbation by hydroxyurea.

The present investigation compared the values obtained for the intestinal crypt cell production rate per hour ( CCPR ) at several sites in the intestine of rats using two variations in the application of metaphase arrest technique. The CCPR was determined both from the slope of a metaphase accumulation line obtained by linear regression analysis of measurements at several time points and by the single time point accumulation method. The comparison was performed for both the steady state in untreated controls and under perturbed conditions at 6, 12 and 24 h following intraperitoneal administration of 1000 mg/kg bodyweight of hydroxyurea to rats. In the steady state, the metaphase accumulation values were linear up to 3 h after vincristine sulfate in the proximal intestine (stomach to proximal ileum) and linear for up to 3 1/2 h in the distal ileum and the colon. Consequently the 3 h time point was selected for evaluation of CCPR values using the single time point method. The two methods gave equivalent results in the steady state, although in situations where there was good linearity of metaphase accumulation, the values obtained by the regression method were usually more precise. In the perturbed intestine poorer linearity of metaphase accumulation was observed and the duration of linearity was reduced sometimes to 2-2 1/2 h. Overall, under these circumstances, estimation of average CCPR was more precise by the single time point accumulation method. More importantly, significant differences were sometimes evident between the results of these two methods when applied to the same data.

Animals↗
PubMed1984

Evaluation of the effects of pentagastrin, gastrin and pancreatic glucagon on cell proliferation in the rat gastrointestinal tract.

The effects of six injections of a range of doses (100-1000 micrograms/kg bodyweight) of pentagrastrin and single injection of a range of doses of porcine gastrin (10-40 micrograms/kg bodyweight) and pancreatic glucagon (25-100 micrograms/kg bodyweight) on cell proliferation in the intestine of fasted rats has been investigated. The end-point employed included the measurement of 14C leucine incorporation and thymidine-derived tritium content of the body of the stomach, duodenum, jejunum, ileum and colon. The carbon 14 and tritium content per microgram of tissue in triplicate samples of fifty individually dissected crypts of glands were determined. From these data and the wet weight of the washed, blotted, intestinal segments, values for crypts/micrograms tissue and crypts/segment were calculated. The results demonstrated that pentagastrin at physiological doses decreased cell proliferation slightly in stomach, while gastrin and glucagon were without effect. In the small intestine, pentagastrin and gastrin were without significant effect with the exception that they increased the weight of the duodenum. In contrast, a high physiological dose of glucagon increased DNA and protein synthesis throughout the small bowel, but particularly in the ileum. Pharmacological doses of pentagastrin and all doses of gastrin appeared to increase cell proliferation in the colon although the possibility could not be excluded that this was due to stimulation of precursor uptake. Gastrin also increased colonic weight. Glucagon had no effects in the colon. These observations are compatible with the hypothesis that (i) the primary effects of gastrin and pentagastrin on the proximal intestine are as secretogogues and effects on cell proliferation may be secondary, (ii) gastrin and pentagastrin at physiological levels do not stimulate small intestinal cell proliferation, however glucagon does, and (iii) gastrin at physiological levels and pentagastrin at pharmacological levels may stimulate cell proliferation in the colon.

Animals↗