Neuronal nicotinic acetylcholine (AcCho) receptors composed of alpha7-subunits (alpha7-AcChoRs) are involved in many physiological activities. Nevertheless, very little is known about their single-channel characteristics. By using outside-out patch-clamp recordings from Xenopus oocytes expressing wild-type (wt) alpha7-AcChoRs, we identified two classes of channel conductance: a low conductance (gamma(L)) of 72 pS and a high one (gamma(H)) of 87 pS, with mean open-times (tau(op)) of 0.6 ms. The same classes of conductances, but longer tau(op) (3 ms), were seen in experiments with chimeric alpha7 receptors in which the wtalpha7 extracellular C terminus was fused to the green fluorescent protein (wtalpha7-GFP AcChoRs). In contrast, channels with three different conductances were gated by AcCho in oocytes expressing alpha7 receptors carrying a Leu-to-Thr 248 mutation (mutalpha7) or oocytes expressing chimeric mutalpha7-GFP receptors. These conductance levels were significantly smaller, and their mean open-times were larger, than those of wtalpha7-AcChoRs. Interestingly, in the absence of AcCho, these oocytes showed single-channel openings of the same conductances, but shorter tau(op), than those activated by AcCho. Accordingly, human homomeric wtalpha7 receptors open channels of high conductance and brief lifetime, and fusion to GFP lengthens their lifetime. In contrast, mutalpha7 receptors open channels of lower conductance and longer lifetime than those gated by wtalpha7-AcChoRs, and these parameters are not greatly altered by fusing the mutalpha7 to GFP. All this evidence shows that GFP-tagging can alter importantly receptor kinetics, a fact that has to be taken into account whenever tagged proteins are used to study their function. 相似文献
OBJECTIVE: To evaluate potential associations of vascular endothelial growth factor (VEGF) gene polymorphisms with Beh?et's disease (BD) and disease expression. METHODS: Case patients were 122 consecutive Italian patients with BD followed at the Rheumatology, Ophthalmology, and Neurology Units in Bologna, Ferrara, Milano, Palermo, Potenza, Prato, Reggio Emilia, and Trento over a 3-year period (1997-99) and who satisfied the International Study Group criteria for BD. Also selected as a control group were 200 healthy age and sex matched blood donors. All patients with BD and controls were genotyped by polymerase chain reaction and allele-specific oligonucleotide techniques for +936 C/T (rs3025039) and -634 C/G (rs2010963) mutations and for an 18 base pair (bp) insertion/deletion (I/D) polymorphism at -2549 of the the VEGF promoter region. In vitro release of VEGF by peripheral blood mononuclear cells (PBMC) was investigated by ELISA in healthy controls homozygous for the polymorphisms studied. RESULTS: The carriage rates of the alleles I and -634C were significantly more frequent in patients with BD than in healthy controls [p corr = 0.036, OR 1.8 (95% CI 1.1-2.9) and p corr = 0.05, OR 1.8 (95% CI 1.1-3.0), respectively]. While the distribution of allele +936T was similar in patients with BD and healthy controls, its frequency was significantly higher in BD patients with posterior uveitis/retinal vasculitis than in those without (p = 0.022, OR 2.4, 95% CI 1.1-5.0). Lipopolysaccharide-stimulated VEGF production from PBMC of healthy subjects was higher in II homozygous than in DD homozygous. CONCLUSION: Our data indicate that carriers of -634C and I alleles are associated with susceptibility to developing BD. 相似文献
Anti-TNF therapies infliximab (IFX), adalimumab (ADA), and golimumab (GOL) are approved for treating moderate to severe ulcerative colitis (UC). In UC, only the switch from IFX to ADA has been investigated, reaching no more than 10–43% remission rates at 12 months.
Aim
Of the present study was to investigate disease outcome after a switch from subcutaneous (SC) agents to the intravenous (IV) agent (IFX).
Methods
In this retrospective multicentre study, we analysed the charts of UC patients unresponsive/intolerant or with secondary loss of response (LOR) to ADA or GOL who were switched to IFX. We evaluated clinical response and remission together with adverse events at 3, 6, and 12 months follow-up.
Results
Seventy-six patients were included; 38 patients started ADA and 38 started GOL for a mean therapy duration of 6?±?6 months. Indications for switch were adverse events in 3%, primary failure in 79%, and LOR in 18% of patients. Clinical remission was reached by 47%, 50%, and 77% of patients, respectively. Patients that switched for LOR did numerically, but not statistically, better than patients who switched for primary failure.
Conclusions
Our data show a superior remission rate in SC to IV anti-TNF switch in UC compared to the IV to SC switch reported in literature. 相似文献
The Xenopus oocyte is a very powerful tool for studies of the structure and function of membrane proteins, e.g., messenger RNA extracted from the brain and injected into oocytes leads to the synthesis and membrane incorporation of many types of functional receptors and ion channels, and membrane vesicles from Torpedo electroplaques injected into oocytes fuse with the oocyte membrane and cause the appearance of functional Torpedo acetylcholine receptors and Cl(-) channels. This approach was developed further to transplant already assembled neurotransmitter receptors from human brain cells to the plasma membrane of Xenopus oocytes. Membranes isolated from the temporal neocortex of a patient, operated for intractable epilepsy, were injected into oocytes and, within a few hours, the oocyte membrane acquired functional neurotransmitter receptors to gamma-aminobutyric acid, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, and glycine. These receptors were also expressed in the plasma membrane of oocytes injected with mRNA extracted from the temporal neocortex of the same patient. All of this makes the Xenopus oocyte a more useful model than it already is for studies of the structure and function of many human membrane proteins and opens the way to novel pathophysiological investigations of some human brain disorders. 相似文献
Introduction: Hepatitis C virus (HCV) infection has been associated with a large spectrum of glomerular lesions in both native and transplanted kidneys. The most common HCV-associated renal disease is type I membranoproliferative glomerulonephritis usually, but not invariably, in the context of type II mixed cryoglobulinemia (MC). HCV infection is also the major cause of MC, a systemic vasculitis characterized by involvement of small and, less frequently, medium-sized vessels. Conflicting data exist on the treatment of HCV-associated glomerular disease.
Areas covered: This review examines the drugs used for management of HCV-related kidney disease and discusses current and new strategies. All literature concerning treatment of HCV-associated kidney disease has been retrieved by electronic (Medline) and manual searches.
Expert opinion: Various approaches have been recommended for the treatment of HCV-related glomerular disease, including immunosuppressive therapy (corticosteroids, cytotoxic agents and mAbs) and antiviral therapy. These regimens should be considered according to the level or proteinuria and kidney failure. Immunosuppressive agents are recommended in patients with nephrotic syndrome and/or rapidly progressive kidney failure. Antiviral treatment based on IFN and/or ribavirin or triple antiviral therapy (PEGylated-IFN/ribavirin/telaprevir or boceprevir) has been adopted in patients with moderate proteinuria and slow loss of kidney failure; however, the number of patients enrolled was small. Some patients with HCV-related cryoglobulinemic glomerulonephritis have been treated with rituximab but some issues about its role remain to be clarified. The antiviral treatment of HCV-related glomerular disease is expected to improve in the near future with new agents provided with greater efficacy and safety. However, the affordability of these drugs remains a pivotal issue, particularly in low-income countries. 相似文献
Digestive Diseases and Sciences - Haemorrhoids, a common ailment afflicting mostly Western patients, can produce bothersome symptoms, in particular pain, pruritus, and bleeding. There is a wide... 相似文献
Venous thromboembolism (VTE) is a common complication among hospitalized patients. Pharmacological thromboprophylaxis has emerged as the cornerstone for VTE prevention. As trials on thromboprophylaxis in medical patients have proven the efficacy of both low-molecular-weight heparins (LMWHs) and unfractionated heparin (UFH), all acutely medical ill patients should be considered for pharmacological thromboprophylaxis. Unlike in the surgical setting where the risk of associated VTE attributable to surgery is well recognized, and where widespread use of pharmacological thromboprophylaxis and early mobilization has resulted in significant reductions in the risk of VTE, appropriate VTE prophylaxis is under-used in medical patients. Many reasons for this under-use have been identified, including low perceived risk of VTE in medical patients, absence of optimal tools for risk assessment, heterogeneity of patients and their diseases, and fear of bleeding complications. A consistent group among hospitalized medical patients is composed of elderly patients with impaired renal function, a condition potentially associated with bleeding. How these patients should be managed is discussed in this review. Particular attention is devoted to LMWHs and fondaparinux and to measures to improve the safety and the efficacy of their use. 相似文献