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121.
122.
Reduction in the developmental potential of intrathymic T cell progenitors with age 总被引:12,自引:0,他引:12
Min H Montecino-Rodriguez E Dorshkind K 《Journal of immunology (Baltimore, Md. : 1950)》2004,173(1):245-250
Current models of thymic involution propose that intrinsic developmental defects in intrathymic T cell precursors do not contribute to age-related declines in thymopoiesis. This premise was reassessed in a murine model in light of the recent definition of the early T lineage progenitor (ETP), which appears to be the earliest intrathymic precursor defined to date. The results demonstrate that the frequency of ETP declines with age and their potential to reconstitute the thymus is diminished. These findings are consistent with the fact that ETP from aged mice proliferate less and have a higher rate of apoptosis than their counterparts from young animals. Taken together, these data suggest that age-associated changes in T cell precursors should be considered when attempts to rejuvenate the involuted thymus are made. 相似文献
123.
Edderkaoui M Hong P Vaquero EC Lee JK Fischer L Friess H Buchler MW Lerch MM Pandol SJ Gukovskaya AS 《American journal of physiology. Gastrointestinal and liver physiology》2005,289(6):G1137-G1147
The extracellular matrix (ECM) facilitates pancreatic cancer cells survival, which is of central importance for pancreatic adenocarcinoma that is highly fibrotic. Here, we show that reactive oxygen species (ROS) mediate the prosurvival effect of ECM in human pancreatic cancer cells. Fibronectin and laminin stimulated ROS production and NADPH oxidase activation in pancreatic cancer cells. Both pharmacological and molecular approaches show that fibronectin stimulated ROS production through activation of NADPH oxidase and NADPH oxidase-independent pathways and that 5-lipoxygenase (5-LO) mediates both these pathways. Analyses of the mechanisms of ROS production by ECM proteins and growth factors indicate that activation of NADPH oxidase (Nox4) is a common mechanism employed both by ECM proteins and growth factors to increase ROS in pancreatic cancer cells. We also found that Nox4 is present in human pancreatic adenocarcinoma tissues and that these tissues display membrane NADPH oxidase activity. ECM proteins and growth factors activate NADPH oxidase through different mechanisms; in contrast to ECM proteins, growth factors activate NADPH oxidase through 5-LO-independent mechanisms. Inhibition of 5-LO or NADPH oxidase with pharmacological inhibitors of these enzymes and with Nox4 or 5-LO antisense oligonucleotides markedly stimulated apoptosis in cancer cells cultured on fibronectin. Our results indicate that ROS generation via 5-LO and downstream NADPH oxidase mediates the prosurvival effect of ECM in pancreatic cancer cells. These mechanisms may play an important role in pancreatic cancer resistance to treatments and thus represent novel therapeutic targets. 相似文献
124.
H. Schneider M. P. C. Schneider M. I. C. Sampaio E. Montoya J. Tapia F. Encarnacion N. P. Anselmo F. M. Salzano 《American journal of physical anthropology》1993,90(3):345-350
Specimens from three species of the Callicebus moloch group—C. Moloch (N = 80), C. brunneus (N = 166), and C. cupreus (N = 23)—were studied. Twenty genetic loci were investigated through electrophoresis, genetic distances were estimated, and the results compared with the available cytogenetic data. Low values of genetic distance were encountered, contrasting with relatively large chromosome differences. We propose that recent karyotypic rearrangements, rather than other Pleistocene events, were the major evolutionary mechanisms determining speciation in these three taxa. © 1993 Wiley-Liss, Inc. 相似文献
125.
Maria I. C. Sampaio Maria P. C. Schneider Carmem M. L. Barroso Barbara T. F. Silva Horacio Schneider Filomeno Encarnacion Enrique Montoya Francisco M. Salzano 《International journal of primatology》1991,12(4):389-402
Carbonic anhydrase II electrophoretic patterns were investigated in 3113 animals belonging to 12 genera and 24 species of
New World primates. Polymorphism was detected in 13 species. A total of 24 different alleles was postulated to explain the
variability found; the genusAotus showed the highest (eight) number of such alleles. Three genera of the family Callitrichidae (Callithrix, Saguinus, andCebuella) presented five alleles that were not found among the Cebidae. Important markers at the generic level were observed inCallicebus (CA2
*6 andCA2
*12),Cebus (CA2
*10, CA2*16, andCA2
*21), andAotus (CA2*3, CA2*4, CA2*5, CA2*9, CA2*15, CA2*17, CA2*22, CA2*23). CA2*13 seems to be the most common allele among the Cebidae; six genera of this family showed frequencies higher than 70% of it. 相似文献
126.
127.
J Vaquero S Coca M Moreno S Oya A Arias M Zurita C Morales 《Histology and histopathology》1992,7(4):647-651
A series of 18 tumors with histological features of oligodendrogliomas, induced in the rat by means of transplacental ethyl-nitrosourea administration were studied for immunohistochemical demonstration of neuronal (synaptophysin and neurofilament protein) and glial (gliofibrillar acidic protein and vimentin) markers. Most of the tumors showed cells with strong positivity to synaptophysin and to a lesser degree, to neurofilament protein, suggesting the neuronal character of these neoplasms. In 10 tumors, cells with strong positivity to vimentin were found, and in three cases, tumoral cells expressed gliofibrillar acidic protein. The observation that ENU-induced oligodendroglial tumors express neuronal and, to a minor degree, glial markers, suggests their interpretation as primitive neuroectodermal tumors with clear neuronal differentiation. 相似文献
128.
129.
Background
Cell therapy using mesenchymal stromal cells (MSCs) offers new perspectives in the treatment of traumatic brain injury (TBI). The aim of the present study was to assess the impact of platelet-rich plasma scaffolds (PRPS) as support of MSCs in a delayed phase after severe TBI in rats.Methods
TBI was produced by weight-drop impact to the right cerebral hemisphere. Two months after TBI, four experimental groups were established; saline, PRPS, MSCs in saline, or MSCs in PRPS was transplanted into the area of brain lesion through a small hole. All groups were evaluated in the course of the following 12 months after therapy and the animals were then humanely killed.Results
Our results showed that a greater functional improvement was obtained after the administration of MSCs in PRPS compared with the other experimental groups.Discussion
PRPS enhanced the benefit of cell therapy with MSCs to treat chronic brain damage in rats that suffered a severe TBI. The present findings suggest that the use of intralesional MSCs supported in PRPS may be a strategy of tissue engineering for patients with established neurological severe dysfunction after a TBI. 相似文献130.
Transgenic pea seeds as bioreactors for the production of a single-chain Fv fragment (scFV) antibody used in cancer diagnosis and therapy 总被引:2,自引:0,他引:2
Perrin Yolande Vaquero Carmen Gerrard Ian Sack Markus Drossard Jürgen Stöger Eva Christou Paul Fischer Rainer 《Molecular breeding : new strategies in plant improvement》2000,6(4):345-352
Field pea (Pisum sativum L.) appears well suited for the production of high-value molecules such as recombinant antibodies, with well-established agricultural practices world-wide and seeds that are easily stored and distributed. In order to evaluate the suitability of this grain legume for the production of biologically active antibodies, we transformed peas with a cDNA encoding the single-chain Fv fragment scFvT84.66. This scFv is derived from the monoclonal antibody T84.66, which recognises the well-characterised tumour-associated carcinoembryonic antigen. The antibody is useful for in vitro immunodiagnosis and in vivo imaging of human cancers. We expressed scFvT84.66 cDNA under the control of the seed-specific legumin A promoter. We targeted the antibody to the endoplasmic reticulum for better stability and high accumulation. Transgenic plants produced up to 9 g per gram fresh weight of functional scFvT84.66 in their seeds. The transgene was stably inherited and expressed in the progeny, and the antibody remained active after storage in dried transgenic seeds for two months at room temperature. Our results demonstrate the suitability of grain legume seeds to produce biologically active recombinant antibodies, and the utility of field pea seeds as production vehicles for recombinant pharmaceutical macromolecules. 相似文献