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BACKGROUND: Nephroblastoma (Wilms' tumor) is the most common malignant tumor of the kidney in children but is rare in adults. The stage and histopathology of the tumor are the most important prognostic indicators. The common sites of metastasis are lung, liver and lymph nodes. Skeletal metastasis is exceedingly rare in both pediatric and adult nephroblastoma. We report an unusual case of a skeletal metastasis of adult nephroblastoma that developed nine years after the diagnosis of a typical nephroblastoma of favorable histology and that was diagnosed by computed tomography (CT)-guided fine needle aspiration cytology. CASE: Following a right radical nephrectomy for adult nephroblastoma and two local recurrences two and three years later, a 74-year-old woman presented with low back pain. CT and magnetic resonance imaging revealed lytic lesions in the 10th and 12th thoracic vertebrae. Smears prepared from specimens obtained through CT-guided fine needle aspiration biopsy were moderately cellular, with small, round cells arranged singly and in loosely cohesive clusters. These cells had inconspicuous nucleoli and scanty to moderate amounts of cytoplasm. The cells were also positive for cytokeratin and vimentin and appeared similar to areas of blastema in the original tumor. CONCLUSION: A definitive diagnosis of metastatic adult nephroblastoma in thoracic vertebrae was made possible by CT-guided fine needle aspiration cytology in conjunction with clinical and radiologic findings and by using ancillary modalities, such as immunohistochemical studies.  相似文献   
23.
In the highly organized and complex process of mammalian spermatogenesis, the development of an undifferentiated diploid germ cell into a fully differentiated and mature spermatozoon is orchestrated in a time frame unique for each species including man. If the various hormonal signals including environmental cues that play a critical part in initiating these events are not properly executed, various deficiencies including delay in sexual maturity or puberty are likely. In this study we have followed testicular development and spermatogenesis in the FSH receptor knockout (FORKO) mice from Day 7 onward by using histology and quantitative DNA flow cytometry. The drastic reduction in testicular weight and shrinkage of seminiferous tubules that occurred at this early age persisted into the adult stage in the FORKOs, suggesting inhibition of the initial developmental processes. The round spermatids that were clearly abundant on Day 21 in the wild-type and heterozygous males were few and present only in some tubules of the FORKOs. There were no elongated spermatids in FORKO males on Day 35. The sperm produced by Day 49 FORKOs were already aberrant, a feature that persisted into adulthood in these animals. As all these changes occurred in a background of normal circulating testosterone levels, we may conclude that the delay in testicular development is a consequence of the loss of FSH-receptor signaling. The delay in sexual maturity of FORKOs was accompanied by reduction in fertility as evidenced by mating studies. Based on these data we suggest that the FORKO mouse might be a useful experimental model to define the molecular mechanisms that underlie the delay in puberty.  相似文献   
24.
Amidotriphosphate (0.1 M) in aqueous solution at near neutral pH in the presence of magnesium ions (0.25 M) converts glycolaldehyde (0.025 M) within days at room temperature into glycolaldehyde phosphate in (analytically) nearly quantitative yields (76% in isolated product). This robust phosphorylation process was observed to proceed at concentrations as low as 30 M glycolaldehyde and 60 M phosphorylation reagent under otherwise identical conditions. In sharp contrast, attempts to achieve a phosphorylation of glycolaldehyde with cyclotriphosphate (trimetaphosphate) as phosphorylating reagent were unsuccessful. Mechanistically, the phosphorylation of glycolaldehyde with amidotriphosphate is an example of intramolecular delivery of the phosphate group.  相似文献   
25.
The conformations of peptides corresponding to KLLIALVLCFLPLAALG have been examined in trifluoroethanol (TFE), aqueous medium by circular dichroism spectroscopy and in the solid state by Fourier Transform Infra Red Spectroscopy (FTIR). The 17-residue parent peptide and peptides corresponding to shorter segments LVLCFLPLAALG and CFLPLAALG showed preference for helical conformation in TFE. Even the shorter hydrophobic peptides corresponding to KLLIA and LVL showed propensity for beta-turn conformations in TFE. However, peptides corresponding to the relatively polar segment FLPLAALG were unordered in TFE. In water, peptides that showed ordered conformation in TFE preferred beta-conformation. In solid-state, FTIR spectra indicated that the hydrophobic peptides adopt beta-structures with extensive hydrogen bonded network in the solid-state. The hydrophobic core segment thus appears to dictate the conformational propensity of the peptide.  相似文献   
26.
As part of a project that aims at screening TNA-related oligonucleotide systems in which threose backbone units may have some or all of their oxygen functions replaced by nitrogen, two TNA analogs containing (2'NH)- and (3'NH)-phosphoramidate groups, respectively, in place of phosphodiester groups were synthesized. They show base-pairing properties that are very similar to those of TNA itself. We also synthesized 2',3'-diamino analogs of alpha-L-threofuranosyl mononucleosides, yet attempts to convert them to TNA analogs containing phosphodiamidate linker groups were not successful. Such 2',3'-diamino derivatives of threofuranosyl nucleosides may be of interest, however, as building blocks of TNA analogs that contain non-phosphorous linker groups.  相似文献   
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A series of C3 cyclic side-chain analogues of classical cannabinoids were synthesized to probe the ligand binding pocket of the CB1 and CB2 receptors. The analogues were evaluated for CB1 and CB2 receptor binding affinities relative to delta(8)-THC. The C3 side-chain geometries of the analogues were studied using high field NMR spectroscopy and quantum mechanical calculations. The results of these studies provide insights into the geometry of the ligand binding pocket of the CB1 and CB2 receptors.  相似文献   
29.
Newcastle disease virus (NDV) edits its P gene by inserting one or two G residues at the conserved editing site (UUUUUCCC, genome sense) and transcribes the P mRNA (unedited), the V mRNA (with a +1 frameshift), and the W mRNA (with a +2 frameshift). All three proteins are amino coterminal but vary at their carboxyl terminus in length and amino acid composition. Little is known about the role of the V and W proteins in NDV replication and pathogenesis. We have constructed and recovered two recombinant viruses in which the expression of the V or both the V and W proteins has been abolished. Compared to the parental virus, the mutant viruses showed impaired growth in cell cultures, except in Vero cells. However, transient expression of the carboxyl-terminal portion of the V protein enhanced the growth of the mutant viruses. In embryonated chicken eggs, the parental virus grew to high titers in embryos of different gestational ages, whereas the mutant viruses showed an age-dependent phenomenon, growing to lower titer in more-developed embryos. An interferon (IFN) sensitivity assay showed that the parental virus was more resistant to the antiviral effect of IFN than the mutant viruses. Moreover, infection with the parental virus resulted in STAT1 protein degradation, but not with the mutant viruses. These findings indicate that the V protein of NDV possesses the ability to inhibit alpha IFN and that the IFN inhibitory function lies in the carboxyl-terminal domain. Pathogenicity studies showed that the V protein of NDV significantly contributes to the virus virulence.  相似文献   
30.
Wheat puroindolines enhance fungal disease resistance in transgenic rice   总被引:11,自引:0,他引:11  
Antimicrobial peptides play a role in the immune systems of animals and plants by limiting pathogen infection and growth. The puroindolines, endosperm-specific proteins involved in wheat seed hardness, are small proteins reported to have in vitro antimicrobial properties. Rice, the most widely used cereal crop worldwide, normally does not contain puroindolines. Transgenic rice plants that constitutively express the puroindoline genes pinA and/or pinB throughout the plants were produced. PIN extracts of leaves from the transgenic plants reduced in vitro growth of Magnaporthe grisea and Rhizoctonia solani, two major fungal pathogens of rice, by 35 to 50%. Transgenic rice expressing pinA and/or pinB showed significantly increased tolerance to M. grisea (rice blast), with a 29 to 54% reduction in symptoms, and R. solani (sheath blight), with an 11 to 22% reduction in symptoms. Puroindolines are effective in vivo in antifungal proteins and could be valuable new tools in the control of a wide range of fungal pathogens of crop plants.  相似文献   
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