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61.
Hormonal requirements for growth and differentiation of ob17 preadipocyte cells in vitro 总被引:2,自引:0,他引:2
G Ailhaud E Amri C Cermolacce P Djian C Forest D Gaillard P Grimaldi J Khoo R Négrel G Serrero-Davé 《Diabète & métabolisme》1983,9(2):125-133
The ob17 cell line is a clonal line established from epididymal fat pads of C57 BL/6J ob/ob mice. After conversion into adipose-like cells, ob17 presents both the morphological and biochemical properties of mature rodent fat cells. The adipose conversion process is best represented by a stochastic model in which a pool of stem cells (adipoblasts) gives rise to clusters of adipose cells and to additional stem cells that remain in the population. The role of the different factors involved in the adipose conversion process of ob17 cells is discussed, i.e. 1) mitogenic factors, that enhance the number of committed cells (ACF or adipose conversion factor(s)) 2) lipogenic factors, that enhance the expression of adipocyte enzyme markers (insulin) and 3) adipogenic factors, that are obligatory requirements for adipose conversion (triiodothyronine, growth hormone and other pituitary factors). 相似文献
62.
Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation 总被引:5,自引:12,他引:5
Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death. 相似文献
63.
Brenda Bell CAPT USA MC Dr. Ernest L. Mazzaferri MD FACP 《Digestive diseases and sciences》1993,38(1):185-190
Summary The case history of a 24-year-old woman with Gardner's syndrome [familial adenomatous polyposis (FAP)] and papillary thyroid carcinoma is presented, representing the 37th report of this association. Although FAP is transmitted as an autosomal dominant trait with similar penetrance in both sexes, thyroid carcinoma has been found almost exclusively in women (94.3%). The majority have been papillary carcinomas (88.5%), which have become apparent during the third decade (average 23.6, range 16–40 years). Most (55.5%) thyroid carcinomas have been discovered 1–17 years after FAP was identified, although some have been found before (29.6%), or at the same time (14.8%) FAP was diagnosed. Multicentric papillary carcinomas have been reported in 64% (14 of 22) of FAP patients, a frequency at least twofold greater than usual. Although papillary carcinoma found before age 30 (as it was in most patients with FAP) typically has an excellent prognosis, one patient with FAP developed distant metastases from thyroid carcinoma and a 28-year-old woman's death was attributed to papillary carcinoma. The high frequency of multicentric papillary thyroid carcinoma in young patients with FAP and the potential for metastases and death due to thyroid carcinoma warrant aggressive diagnostic screening at regular intervals with neck palpation, ultrasonography, and if necessary, fineneedle aspiration biopsy. When thyroid carcinoma is found, total or near-total thyroidectomy should be considered because of the tumor's high likelihood of being multifocal. Since almost 30% of the thyroid carcinomas associated with FAP have been diagnosed 4–12 years before polyposis was identified, young patients presenting with thyroid carcinoma should be questioned regarding bowel function and a family history of gastrointestinal disease, and consideration should be given to periodic testing for fecal occult blood.The views expressed herein are those of the authors and do not necessarily reflect those of the Army or the Department of Defense. 相似文献
64.
Dr. Daniel L. Anderson MD MAJ MC H. Worth Boyce Jr MD COL MC 《Digestive diseases and sciences》1973,18(8):633-640
Eight patients with advanced regional enteritis characterized by multiple areas of involvement, previous surgery (5 of 8), and failure on medical therapy (6 of 8) were placed on total parenteral nutrition for a period of 30 days. In eight of nine courses administered, definite improvement marked by weight gain, diminished pain, decreased diarrhea, and increased serum albumin was found. However, clinical remission was transient in seven of eight successful courses, indicating that parenteral nutrition is not a definitive form of therapy. However, the results suggest that parenteral nutrition may be useful in patients with regional enteritis to a) restore nutrition, b) induce remission, and c) prepare a debilitated patient for surgery. Additional experience is required to determine the efficacy of parenteral nutrition for therapy of fistulae caused by regional enteritis. 相似文献
65.
Gerald E. Smith MD LT COL MC Lynn R. Kime MAJ MC J. Loren Pitcher MD FACP COL MC 《Digestive diseases and sciences》1973,18(11):987-1000
Summary An additional case of Behcet's disease with colonic involvement has been presented. This association is rare, as only 13 prior cases with adequate data were available for comparison. Controversy exists as to whether these cases represented true involvement of the colon by Behcet's disease, coincidental inflammatory bowel disease and Behcet's disease, or merely autoimmune phenomena associated with inflammatory bowel disease. Unusual colonoscopic lesions noted in our patient and other features enumerated in the text suggested to us that at least some of these cases represented primary Behcet's disease involving the colon. 相似文献
66.
67.
Summary In summary, the vascular bed of the stomach is an area of great potential importance to both gastric and vascular physiologists. There are available many technics for its investigation. Simultaneous study of both hemodynamic and secretory phenomena can be conducted on the stomach. In the next few years information concerning the circulation of the stomach may help elucidate problems in the physiology and pathology of gastric secretion. Hightower observed recently: The topic of visceral circulation, particularly as it pertains to the digestive tract, has not been commented upon in recent...Reviews of Physiology. This subject has become increasingly important in the past few years and is an area with which physiologists interested in the digestive system will become more and more concerned.33 相似文献
68.
69.
O'Malley CJ; Rasko JE; Basser RL; McGrath KM; Cebon J; Grigg AP; Hopkins W; Cohen B; O'Byrne J; Green MD; Fox RM; Berndt MC; Begley CG 《Blood》1996,88(9):3288-3298
This report describes the effect of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on platelet production and platelet function in humans. Subjects with advanced solid tumors received PEG-rHuMGDF daily for up to 10 days. There was no increase in circulating platelet count at doses of 0.03 or 0.1 microgram/kg/d by day 12 of study. At doses of 0.3 and 1.0 microgram/kg/d there was a threefold median increase (maximum 10-fold) in platelet count by day 16. The platelets produced in vivo in response to PEG-rHuMGDF showed unchanged aggregation and adenosine triphosphate (ATP)-release responses in in vitro assays. Tests included aggregation and release of ATP in response to adenosine diphosphate (ADP) (10, 5, 2.5, and 1.25 mumol/L), collagen (2 micrograms/mL), thrombin-receptor agonist peptide (TRAP, 10 mumol/L) and ristocetin (1.5 mg/mL). Administration of aspirin to an individual with platelet count of 1,771 x 10(3)/L resulted in the typical aspirin-induced ablation of the normal aggregation and ATP-release response to stimulation with arachidonic acid (0.5 mg/mL), collagen, and ADP (2.5 and 1.25 mumol/L). There was no change in the expression of the platelet-surface activation marker CD62P (P-selectin) nor induction of the fibrinogen binding site on glycoprotein IIb/IIIa as reported by the monoclonal antibody, D3GP3. An elevation of reticulated platelets was evident after 3 days of treatment with PEG-rHuMGDF and preceded the increase in circulating platelet count by 5 to 8 days; this reflected the production of new platelets in response to PEG-rHuMGDF. At later time points, the mean platelet volume (MPV) decreased in a manner inversely proportional to the platelet count. Levels of plasma glycocalicin, a measure of platelet turnover, rose 3 days after the initial increase in the peripheral platelet count. The level of plasma glycocalicin was proportional to the total platelet mass, suggesting that platelets generated in response to PEG-rHuMGDF were not more actively destroyed. Thus, the administration of PEG-rHuMGDF, to humans, increased the circulating platelet count and resulted in fully functional platelets, which showed no detectable increase in reactivity nor alteration in activation status. 相似文献
70.