共查询到20条相似文献,搜索用时 8 毫秒
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Previous work has shown that, following an intramuscular injection of ricin, the toxin becomes localized within histiocytes in the sinuses of lymph nodes draining the 'wound' site. When ricin labelled with colloidal gold was similarly injected, it was found within the same lymphoid cells as seen with native ricin. Biologically inert Indian ink apparently follows a similar fate, as demonstrated by the appearance of carbon particles within sinus histiocytes, as soon as 1 h after intramuscular injection. When the binding in vitro of Indian ink or ricin toxin to sections of lymph node was examined, ricin was seen to bind to the surfaces of the same sinusoidal cells and also, with a much lower frequency, to follicular lymphocytes, whereas Indian ink failed to bind. This indicated an interaction between ricin and cell membrane components. Moreover, this binding was inhibited markedly by the galactose-containing disaccharide, lactose, a target sugar specified by the lectin binding site of ricin and to a much lesser extent by the monosaccharide mannose. 相似文献
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Summary Following a supralethal injection of ricin into thigh muscle of the adult rat, the toxin was demonstrated post-mortem in the para-aortic lymph node, ipsilateral to the side of injection. The relative merits of two immunoenzyme methods, peroxidase anti-peroxidase (PAP) and avidin—biotin—peroxidase complex (ABC) and a silver-enhanced immunogold method (IGSS) were assessed in the detection of ricin in the lymph node tissue. The toxin was clearly seen to be located in association with histiocytes found both within and lining the sinuses of the nodes and also, in some cases, in the subcapsular sinus of the node; the toxin was not demonstrable within lymphoid follicles by light microscopy. However, using electron microscopy and the IGSS technique, cells carrying discrete particles of gold could be visualized within follicular areas. The IGSS and ABC-peroxidase methods were both found to give excellent results without background staining at the light microscopy level. However, when these techniques were used prior to embedding and viewing by electron microscopy, the IGSS technique proved to be far superior. 相似文献
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Kirstin A Carswell Kasim A Behranwala Ashutosh Nerurkar A Gerald PH Gui 《International Seminars in Surgical Oncology : ISSO》2006,3(1):32
A 58 year old lady presented with a right breast cancer and a prior history of malignant melanoma excised from the right chest wall eight years previously. An abnormal axillary lymph node resected contained features of both metastatic breast carcinoma and malignant melanoma. Following oncologic breast cancer management, the patient is well with no evidence of recurrence at three years. 相似文献
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Background
Phyllodes tumors (cystosarcoma phyllodes) are uncommon lesions in the female breast. Rarely, the occurrence of carcinoma within a phyllodes tumor has been reported in the literature, but has never been associated with lymph node metastases. 相似文献6.
The enemy within: ricin and plant cells 总被引:3,自引:0,他引:3
Ricin, a ribosome-inactivating protein from the seeds of the castor oil
plant (Ricinus communis L.) is one of the most potent
cell poisons known. It is able to bind and enter most mammalian cells where
it exploits their fully reversible secretory pathway to reach the
endoplasmic reticulum. Ricin is then able to exit the endoplasmic reticulum
to access the cytosol where it inhibits protein synthesis, thus killing the
cells. Castor bean ribosomes are sensitive to ricin, but the plant has
developed strategies to protect its own cells from suicide. The
intracellular routing of ricin has been traditionally studied by
exogenously adding toxin to mammalian cells and by following its path
through the cell. However, the extreme potency of this protein has
prevented the final membrane transport step from being studied in detail.
Now, the expression of ricin in heterologous plant cells is providing
helpful in elucidating details of both toxin biosynthesis and vacuolar
targeting, and in studying membrane translocation of the catalytic subunit
from the endoplasmic reticulum to the cytosol.Keywords:
Ricin, ribosome-inactivating protein, castor oil plant, seeds,
inhibitor, membrane transport.
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Organization within the mammalian kinetochore 总被引:7,自引:0,他引:7
J. B. Rattner 《Chromosoma》1986,93(6):515-520
The organization within the mammalian kinetochore was examined using whole-mount electron microscopic techniques on chromosomes digested with restriction enzymes or micrococcal nuclease. These preparations revealed that a portion of the kinetochore is highly resistant to nuclease digestion and can be visualized as a discrete structure. The relationship of this structure to the remainder of the chromosome suggests that it represents the outer kinetochore plate. The plate is composed of a series of fibrillar loops that are arranged in a parallel array along the plane of the plate. These fibers are 25–30 nm in diameter. The morphology, particulate substructure, and ultimate susceptibility to nuclease digestion suggest that these fibers contain DNA. A model is presented that suggests that the outer plate contains the apexes of chromatin loops that originate within the body of the primary constriction. 相似文献
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Markgraf Rainer von Gaudecker Brita Müller-Hermelink Hans Konrad 《Cell and tissue research》1982,225(2):387-413
Summary Lymph nodes of human fetuses from the 11th to the 20th gestational week (g.w.) were investigated by light- and electron microscopy under particular consideration of the development of the T-cell and the B-cell regions and their specific reticulum cells. Lymph node development begins as a mesenchymal condensation, containing capillaries and mesenchymal cells; this primordium bulges into a lymph sac. Within the primordium of the lymph node granulopoiesis and erythropoiesis occur temporarily from the 12th to the 14th g.w. The first lymphoid cells and undifferentiated blast cells are seen in the 12th g.w.; monocytes and macrophages can be found from the 13th g.w. onward.The development of the T-cell regions begins during the 13th g.w., before differentiation into cortex and medulla becomes obvious in the 14th g.w. Near the marginal sinus, cells displaying features of interdigitating reticulum cells (IDC) show similarities to monocytes. The morphological differentiation of the IDC is complete in the 17th g.w. when they are found in the paracortical region. Among the IDC, lymphoid cells with features of thymocytes are arranged in small groups.The first indication of the development of B-cell regions can be recognized in the 14th g.w. when precursors of dendritic reticulum cells (DRC) are seen near the marginal sinus; this area also displays lymphoblasts, immunoblasts, and plasmoblasts. During the 20th g.w. small primary follicles are discernible in the outer cortex; in addition to blast cells they contain small lymphocytes, none of which show features of thymocytes. The morphological development of DRCs is not entirely complete until the 20th g.w.; however, some cells already show a characteristic network of interwoven processes.The probable origin of (i) the IDC from monocytes, and (ii) the DRC and fibroblastic reticulum cells from a common type of mesenchymal precursor cells, as well as their significance for a specific micromilieu in the T-cell and the B-cell regions, are discussed.This investigation was supported by grants from the Deutsche Forschungsgemeinschaft and the Sonderforschungsbereich 111 of the Deutsche ForschungsgemeinschaftThe authors appreciate the contribution of human fetal material from Dr. J. von Hollweg and Dr. J. Körner, Hospital Heidberg, Hamburg, and the excellent technical assistance of Mrs. O.M. Bracker, Mrs. H. Hansen, Mrs. R. Köpke, Mrs. I. Knauer, Mrs. F. Müller, Mrs. H. Siebke, and Mrs. H. Waluk 相似文献
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Summary A recent study of lymph nodes of the rat showed that they are morphologically and physiologically compartmentalized. A compartment of a node includes a portion of subcapsular sinus into which the lymph, entering via the related afferent lymphatic opening, is filtered. The study also showed that colloidal carbon injected locally in a small dose becomes predominantly associated with the areas of the inner wall of the subcapsular sinus that cover the extrafollicular zone of the peripheral cortex. Little carbon is seen over the folliculo-nodules (follicles with a nodule or germinal center). The question arose as to whether drained natural substances, as antigens and antibodies, follow the same pattern of distribution in the subcapsular sinus as the carbon. Therefore, small doses of fluorescein isothyocyanate (FITC)-conjugated antigens were injected locally into normal rats whose own antibodies in the nodes were stained by immunofluorescence. The pattern of distribution of the antigens in the draining nodes was found to be the same as that of the carbon. Furthermore, the lymph-carried antibodies of the rats were found to follow the same pattern. The morphological basis for such a pattern is explained. The results are further discussed with regard to the probable normal entry route of lymph-carried antigens in the parenchyma of nodes.Supported by a grant from the Université de Montréal 相似文献
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In the field of immunology, to understand the progression of an immune response against a vaccine, an infection or a tumour, the response is often followed over time. Similarly, the study of lymphocyte homeostasis requires time course experiments. Performing these studies within the same mouse is ideal to reduce the experimental variability as well as the number of mice used. Blood withdrawal allows performance of time course experiments, but it only gives information about circulating lymphocytes and provides a limited number of cells. Since lymphocytes circulating through the body and residing in the lymph nodes have different properties, it is important to examine both locations. The sequential removal of lymph nodes by surgery provides a unique opportunity to follow an immune response or immune cell expansion in the same mouse over time. Furthermore, this technique yields between 1-2x10(6) cells per lymph node which is sufficient to perform phenotypic characterization and/or functional assays. Sequential lymph node surgery or lymphadenectomy has been successfully used by us and others. Here, we describe how the brachial and inguinal lymph nodes can be removed by making a small incision in the skin of an anesthetised mouse. Since the surgery is superficial and done rapidly, the mouse recovers very quickly, heals well and does not experience excessive pain. Every second day, it is possible to harvest one or two lymph nodes allowing for time course experiments. This technique is thus suitable to study the characteristics of lymph node-residing lymphocytes over time. This approach is suitable to various experimental designs and we believe that many laboratories would benefit from performing sequential lymph node surgeries. 相似文献
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Summary A casting technique has been employed to display in three dimensions, the lymphatic microcirculation within the human lymph node. The casting compound filled the marginal sinus, and diffusely permeated the cortical lymphoid parenchyma. However, deep within the lymph node in the medullary region, the medium remained within the limits of the sinus walls. The casts showed well-defined channels appearing similar to vessels. These converged into larger vessels, which drained into efferent lymphatics leaving the node at the hilus.Electron microscopic examination showed that the outer wall of the marginal sinus and the trabecular side of trabecular sinuses had an intact, continuous endothelium with a basement membrane. However, gaps were present in the inner wall of the marginal sinus, as well as in the parenchymal wall of the trabecular sinus. In the medulla, the sinuses were lined by endothelial cells which appeared similar to macrophages. The sinus lining was incomplete and possessed numerous perforations. These observations indicated that sinus walls adjacent to connective tissue served as a barrier to cell movement, but those adjacent to a large lymphoid cell population had gaps, with cells in apparent transit between sinus lumen and parenchyma. 相似文献
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《The Journal of cell biology》1993,120(5):1083-1091
The location of the cis-acting DNA sequences that direct the assembly of the mammalian kinetochore is not known. A variety of circumstantial evidence, however, has led to the widespread belief that they are present throughout the kinetochore including the kinetochore outer plate. To investigate this question directly, we have used two independent methods to localize DNA in and around the mammalian kinetochore. Both methods fail to reveal DNA in the outer kinetochore plate, finding instead that the outer-most detectable DNA in the centromere is located in the inner kinetochore plate. Our results imply that the outer kinetochore plate is primarily a proteinaceous structure. It is thus unlikely that fibers observed in the outer plate correspond to chromatin, as previously assumed. Our observations suggest that current models of kinetochore structure may need to be reconsidered. 相似文献