彩色多普勒超声对移植肾急性排斥反应的评价

目的:肾移植的成功与否关键在于及时发现和正确处理排斥反应。探讨无创伤性形态学和血流动力学检查手段彩色多普勒超声在移植肾急性排斥反应中的作用,为临床评估肾移植效果及移植肾功能提供客观的辅助性数据。方法:选择2004-01/2005-12在南京医科大学附属第一医院、江苏省人民医院行同种异体移植肾患者57例,其中经穿刺活检证实或最后临床诊断为急性移植肾排斥反应者22例,未发生排斥反应等并发症的移植肾功能正常者35例,患者均知情同意。采用Philips EnVisor彩色多普勒超声血流显像仪,对急性排斥反应肾移植患者进行二维超声和彩色多普勒血流显像检测,观察排斥反应患者甲基强的松龙冲击治疗前后移植肾脏的大小、形态结构、肾内血管树分布、血流灌注以及各级动脉血流参数(阻力指数,搏动指数)等指标的变化,并与移植肾功能正常患者进行比较。结果:急性排斥反应组2例患者发生严重并发症死亡,进入结果分析急性排斥反应组20例,移植肾功能正常组35例。①发生急性排斥反应时肾移植患者移植肾体积明显大于肾功能正常组(P<0.01);肾实质增厚,皮髓质界限模糊。给予甲基强的松龙冲击治疗后急性排斥反应组患者肾脏厚径显著小于治疗前(P<0.05);肾实质回声减低,皮髓质交界变清。②发生急性排斥反应时肾移植患者移植肾血流阻力指数、搏动指数均显著高于移植肾功能正常组(P<0.01)。治疗后急性排斥反应组患者肾血流阻力指数、搏动指数均显著低于治疗前(P<0.01),与移植肾功能正常组差异无显著性意义(P>0.05)。结论:彩色多普勒超声作为一种简便、经济的无创性技术,对移植肾血流阻力指数、搏动指数的追踪观察可为临床上评估肾移植效果提供较可靠的客观依据,对移植肾急性排斥反应的早期诊断有较高的评估价值。     

Factor V is activated and cleaved by platelet calpain: comparison with thrombin proteolysis

Platelets are known to process human factor V during secretion and/or membrane binding. We studied the functional and structural changes produced in human factor V by purified human platelet calpain (calcium- activated thiol protease) and compared the alterations with those induced by thrombin. A maximum increase in coagulant activity of 2.5- fold was observed when factor V (1 U/mL, 33 nmol/L) was incubated with calpain (0.03 U/mL, 2.7 nmol/L) in comparison with a 8.8-fold increment for alpha-thrombin (0.7 U/mL, 8 nmol/L) at 25 degrees C. Thrombin additions to reactions initiated by calpain resulted in further activation comparable to that of thrombin alone, whereas the subsequent addition of calpain had no effect on the extent or pattern of the activation of factor V by thrombin. The cleavage pattern of factor V produced by these two enzymes are distinctly different. Although thrombin activation eventually results in four final components designated C1 (150 kd), D (105 kd), E (71 kd), and F1F2 (71 to 74 kd), calpain yields initial components of 200 kd and 160 kd within one minute. Further digestion of the 200 kd species by calpain gives rise first to a polypeptide of 160 kd that is converted to a 140 kd and a 120 kd species by two minutes with an increase in coagulant activity. Immunoblotting of these fragments with the monoclonal antibody (MoAb) B10 directed to factor V and the thrombin-generated C1 fragment yields results demonstrating a common epitope in these calpain-generated components of 200, 160, 140 and 120 kd. The degradation of the initial 160 kd polypeptide gives rise to polypeptides of 100 and 65 kd, both undetectable on immunoblotting with MoAb B10. The 130, 87, 58, and 48 kd components are of less certain origin. Thus, platelet calpain generates a complex but reproducible cleavage pattern different from thrombin that may explain the partial activation observed. Nevertheless, calpain processing may play a role in early hemostatic reactions involving platelets before the appearance of the first thrombin molecule.     

Role of p21 RAS in p210 bcr-abl transformation of murine myeloid cells

The p21 RAS product has been implicated as part of the downstream signaling of certain nonreceptor tyrosine kinase oncogenes and several growth factor receptor-ligand interactions. We have reported that the chronic myelogenous leukemia oncogene p210 bcr-abl transforms a growth- factor-dependent myeloid cell line NFS/N1.H7 to interleukin-3 (IL-3) independence. In these p210 bcr-abl-transformed cells (H7 bcr-abl.A54) and in two other murine myeloid cell lines transformed to IL-3 independence by p210 bcr-abl, endogenous p21 RAS is activated as determined by an elevated ratio of associated guanosine triphosphate (GTP)/guanosine diphosphate (GDP), assayed by thin-layer chromatography of the nucleotides eluted from p21 RAS after immunoprecipitation with the Y13-259 antibody. Treatment of p210 bcr-abl-transformed cells with a specific tyrosine kinase inhibitor herbimycin A resulted in diminished tyrosine phosphorylation of p210 bcr-abl and associated proteins, without major reduction in expression of the p210 bcr-abl protein itself. Inhibition of p210 bcr-abl-dependent tyrosine phosphorylation resulted in a reduction of active p21RAS-GTP complexes in the transformed cells, in diminished expression of the nuclear early response genes c-jun and c-fos, and in lower cellular proliferation rate. To further implicate p21 RAS in these functional events downstream of p210 bcr-abl tyrosine phosphorylation, we targeted G- protein function directly by limiting the availability of GTP with the inosine monophosphate dehydrogenase inhibitor, tiazofurin (TR). In p210 bcr-abl-transformed cells treated for 4 hours with TR, in which the levels of GTP were reduced by 50%, but GDP, guanosine monophosphate, and adenosine triphosphate (ATP) were unaffected, p210 bcr-abl tyrosine phosphorylation was at control levels. However, expression of c-fos and c-jun nuclear proto-oncogenes were strongly inhibited and p21 RAS activity was downregulated. These findings show that p210 bcr-abl transduces proliferative signals, in part, through downstream activation of p21 RAS. Furthermore, p21 RAS activity is linked to pathways that regulate c-jun and c-fos expression.     

Single-acquisition chemical-shift imaging of a binary system with use of stimulated echoes

A method for separating binary chemical-shift components with a single image data acquisition by means of stimulated echoes is demonstrated. With a strategy analogous to the modified Dixon method, three stimulated echoes were acquired to form three complex images. In each of the images, the complex pixel intensities were imparted, by design of the pulse sequence, with a phase factor carrying chemical-shift or field inhomogeneity information. With these three images, true fat/water separation can be obtained in biologic tissues. Studies at high field strength (4.7 T) on a toluene phantom, a pseudo-binary chemical-shift system, were used to evaluate the applicability of the method. Its clinical feasibility was demonstrated on a healthy human subject in a 0.6-T whole-body imaging system.     

Persistent Erection (Priapism) for Months with Concomitant Infertility in Rats due to Protein-Energy-Malnutrition

Monatelange Erektion (Priapismus) mit konsekutiver Infertitität bei Ratten als Folge von Protein-Energie-Mangelernährung
Wachsende, männüche Sprague Dawley Ratten wurden 22 Wochen lang mit einer halbsynthetischen, 9% Rohprotein enthaltenden Diät gefüttert, wobei Kasein (Kontrollgruppe; I) oder Weizenbrotkruste (Gruppe II) die alleinigen Proteinquellen darstellten. Das Kontrollfutter in reduzierter Menge, in Anlehnung an den Futterverzehr der Krusten-Ratten, wurde einem dritten Kollektiv verfüttert (pair-fed-Gruppe; III). Nach 6 Versuchswochen zeigten sich in den Gruppen II und III erste pathomorphologische Genitalveränderungen, die sich in einer monatelangen Erektion manifestierten. Bei 97% der Krusten-Ratten, 67% der isoenergetisch gefütterten Kasein-Ratten, jedoch bei keinem Kontrolltier entwickelte sich am Ende des Beobachtungszeitraums eine Dauererektion. Nach der 15. Versuchswoche erzielten die pair-fed-Ratten 17%, die Krusten-Ratten nur 5% des Gewichtszuwachses der Kasein-Kontrollgruppe. Im Reproduktionstest mit gesunden weibl. SD-Ratten erwies sich nur 1 von 6 Krusten-Ratten als zeugungsfähig, nach anschließender 5wöchiger ad lib. Kasein-Wiederauffütterung konnte eine 83% Fertilität beobachtet werden. Der Pathomechanismus der nutritiv induzierten Dauererektion wird auf die ausgeprägte marastische Stoffwechsellage zurückgeführt, bedarf jedoch weiterer Aufklärung.     

Neutral steroid metabolites in patients with uraemia and after renal transplantation: a quantitative and qualitative study in body fluids

Steroid metabolites enriched from urine, haemofiltrate, and CAPD-dialysate (Continuous Ambulatory Peritoneal Dialysis) were identified by gas chromatography-mass spectrometry and quantified by capillary gas chromatography. The study included twenty healthy controls, twenty-six non-dialysed uraemics, thirty-nine patients on regular dialysis treatment, and twenty-two allograft recipients. Compared to the 24 h urinary excretion rates of controls the excretion rates of androsterone and etiocholanolone were in the lower normal range up to significantly decreased in the body fluids of all patients, and those of the corticoid metabolites were also significantly decreased. 11-Oxygenated androstanolones in urine from non-dialysed uraemics correlated significantly decreased. 11-oxygenated androstano-levels and were significantly increased, but normal in haemofiltrate and CAPD-dialysate, while in urine of allograft recipients the values were significantly lower.