Signals from TGF- superfamily receptors are transduced to the nucleus by Smad proteins, which transcriptionally activate target genes. In Caenorhabditis elegans, defects in a TGF--related pathway cause a reversible developmental arrest and metabolic shift at the dauer larval stage. Null mutations in daf-3 suppress mutations in genes encoding this TGF- signal, its receptors, and associated Smad signal transduction proteins. daf-3 encodes a Smad protein that is most closely related to mammalian DPC4, and is expressed throughout development in many of the tissues that are remodeled during dauer development. DAF-4, the type II TGF- receptor in this pathway, is also expressed in remodeled tissues. These data suggest that the DAF-7 signal from sensory neurons acts as a neuroendocrine signal throughout the body to directly regulate developmental and metabolic shifts in tissues that are remodeled during dauer formation. A full-length functional DAF-3/GFP fusion protein is predominantly cytoplasmic, and this localization is independent of activity of the upstream TGF--related pathway. However, this fusion protein is associated with chromosomes in mitotic cells, suggesting that DAF-3 binds DNA directly or indirectly. DAF-3 transgenes also interfere with dauer formation, perhaps attributable to a dosage effect. A truncated DAF-3/GFP fusion protein that is predominantly nuclear interferes with dauer formation, implying a role for DAF-3 in the nucleus. These data suggest that DAF-7 signal transduction antagonizes or modifies DAF-3 Smad activity in the nucleus to induce reproductive development; when DAF-7 signals are disabled, unmodified DAF-3 Smad activity mediates dauer arrest and its associated metabolic shift. Therefore, daf-3 is unique in that it is antagonized, rather than activated, by a TGF- pathway.
SummaryThe INR system was developed to standardize PT reporting in patients on oral anticoagulants. We prospectively collected blood samples from 29 patients with liver impairment (INR 1.5-3.5). Control patients were on warfarin (n = 31). PT’s were measured on an ACL-300 with three thromboplastin reagents. INR’s were calculated using instrument specific ISI’s. Other tests performed were FDP’s, fibrinogen, aPTT, factors II, V, VII and X. The INR’s for each patient in the study population using the three thromboplastin reagents were significantly different (p = 0.0001). Those for the control population were not (p = 0.0658). Fibrinogen, factors V, II and X were different at the 5% level of significance between the populations. FDP’s were detected in 17 study subjects. The INR system is not valid for comparison of patients with liver impairment because different reagents do not give the same INR for the same sample. It is, however, no less valid than the use of PT with different thromboplastin reagents. Further study is recommended.
Ischemia/reperfusion (I/R) injury in organ transplantation significantly contributes to graft failure and is untreatable using current approaches. I/R injury is associated with activation of the complement system, leading to the release of anaphylatoxins, such as C5a, and the formation of the membrane attack complex. Here, we report a novel therapy for kidney I/R injury through silencing of the C5a receptor (C5aR) gene using siRNA. Mice were injected with 50 g of C5aR siRNA 2 days before induction of ischemia. Renal ischemia was then induced through clamping of the renal vein and artery of the left kidney for 25 minutes. The therapeutic effects of siRNA on I/R were evaluated by assessment of renal function, histopathology, and inflammatory cytokines. siRNA targeting C5aR efficiently inhibited C5aR gene expression both in vitro and in vivo. Administering C5aR siRNA to mice preserved renal function from I/R injury, as evidenced by reduced levels of serum creatinine and blood urea nitrogen in the treated groups. Inhibition of C5aR also diminished in vivo production of the pro-inflammatory cytokine tumor necrosis factor-␣ and chemokines MIP-2 and KC, resulting in the reduction of neutrophils influx and cell necrosis in renal tissues. This study demonstrates that siRNA administration represents a novel approach to preventing renal I/R injury and may be used in a variety of clinical settings, including transplantation and acute tubular necrosis.
Background-Ischemia/reperfusion injury is a major factor in graft quality and subsequent function in the transplantation setting. We hypothesize that the process of RNA interference may be used to "engineer" a graft to suppress expression of genes associated with inflammation, apoptosis, and complement, which are believed to cause ischemia/reperfusion injury. Such manipulation of pathological gene expression may be performed by treatment of the graft ex vivo with small interfering RNA (siRNA) as part of the preservation procedure. Methods and Results-Heart grafts from BALB/c mice were preserved in UW solution (control) or UW solution containing siRNAs targeting tumor necrosis factor-␣, C3, and Fas genes (siRNA solution) at 4°C for 48 hours and subsequently transplanted into syngeneic recipients. Tumor necrosis factor-␣, C3, and Fas genes were elevated by ischemia/reperfusion injury after 48 hours of preservation in UW solution. Preservation in siRNA solution knocked down gene expression at the level of messenger RNA and protein in the grafts after transplantation. All grafts preserved in siRNA solution showed strong contraction, whereas grafts preserved in control solution demonstrated no detectable contraction by high-frequency ultrasound scanning. siRNA solution-treated organs exhibited improved histology and diminished neutrophil and lymphocyte infiltration compared with control solution-treated organs. Furthermore, the treated heart grafts retained strong beating up to the end of the observation period (Ͼ100 days), whereas all control grafts lost function within 8 days. Key Words: gene silencing Ⅲ ischemia Ⅲ organ preservation Ⅲ reperfusion Ⅲ RNA, small interfering Ⅲ transplantation O rgan transplantation is the only effective treatment for patients with end-stage organ failure. Although this procedure has been significantly improved over the past 70 years, there are still many challenges to overcome. 1 One of them is ischemia/reperfusion (I/R) injury, which is an unavoidable reality of transplantation. 1 Traditionally, refrigeration and instillation of specialized preservation solutions have been used to mitigate damage during the ex vivo preservation period. The principle underlying cold preservation is that through slowing the metabolism and reducing cell swelling with a specialized preservation solution, the viability and quality of organs will be preserved. Unfortunately, metabolic activity is not completely halted at cold temperature, 2 and anaerobic cellular metabolism continues, albeit at a reduced level. This leads to an accumulation of toxic and harmful metabolites during preservation, which serve to activate immunological processes during reperfusion, causing inflammation and organ injury. 3,4 Conclusion-Incorporation Editorial see p 1027 Clinical Perspective on p 1107Many organ preservation solutions have been developed and applied in transplantation, but despite advances, cold ischemic storage of the heart is still limited to 4 to 6 hours because the preservation solutions are unable to signifi...
Objectives To find out and explore the knowledge and opinion of Chinese people on cardiovascular disease and awareness of cardiac rehabilitation. Design A cross-sectional study using 14-item bilingual (Chinese and English) questionnaires that include information on demographics, health status, cardiovascular disease related knowledge and perception, and awareness and understanding of the cardiac rehabilitation programme.
Metabolic syndrome (MetS) is a complex pathological state consisting of metabolic risk factors such as hypertension, insulin resistance, and obesity. The interconnectivity of cellular pathways within various biological systems suggests that each individual component of MetS may share common pathological sources. Additionally, MetS is closely associated with vasculopathy, including a reduction in microvessel density (MVD) (rarefaction) and elevated risk for various cardiovascular diseases. Microvascular impairments may contribute to perfusion-demand mismatch, where local metabolic needs are insufficiently met due to the lack of nutrient and oxygen supply, thus creating pathological positive-feedback loops and furthering the progression of disease. Sexual dimorphism is evident in these underlying cellular mechanisms, which places males and females at different levels of risk for cardiovascular disease and acute ischemic events. Estrogen exhibits protective effects on the endothelium of pre-menopausal women, while androgens may be antagonistic to cardiovascular health. This review examines MetS and its influences on MVD, as well as sex differences relating to the components of MetS and cardiovascular risk profiles. Finally, translational relevance and interventions are discussed in the context of these sex-based differences.
Malignant Balb/c mouse lung cell clones related to alveologenic carcinoma exhibited low levels of epidermal growth factor (EGF) receptor activity compared to nonmalignant cell clones. Immunoprecipitation of cell homogenates and immunohistochemistry on urethane-induced lung tumors suggest that the absence of activity reflects decreased amounts of EGF receptor protein. Low levels of EGF receptor alone cannot cause neoplastic transformation, since a nonneoplastic cell cone, B5D3, exhibited low levels of EGF receptor despite its nontransformed phenotype. The reduced levels of EGF receptor in malignant clones have been mimicked by long-term (12 h) treatment of a nontransformed cell clone with 200 nM phorbol dibutyrate. The detection of mutated ras oncogene in the transformed cell lines, taken together with the EGF receptor findings, suggests that more than one alteration in the signal transduction pathway may be necessary for transformation in alveologenic adenoma and carcinoma cell systems. A further phenotypic feature of transformation, reduced expression of the extracellular matrix proteins fibronectin and laminin, may be mediated at the transcriptional level.
It is shown that for the eclipsing variable stars MP Mus and SV Cen a least squares fitting procedure is more accurate when a linear (intensity) rather than a logarithmic (magnitude) scale is used.
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