LWMH与VKA对DVT患者院外抗凝效益-风险对比

【目的】通过对经住院治疗后下肢深静脉血栓形成(deep venous thrombosis,DVT)患者院外分别继续应用低分子肝素(low molecule weight heparin,LMWH)或维生素K拮抗剂(vitamin K antagonists,VKA)的效益-风险比的对比研究,探讨较为有效、安全、简便的抗凝方案。【方法】将2008年12月-2011年3月符合纳入标准的患者随机分为A组(应用低分子肝素钙)和B组(应用华法林),并随访6个月,期间通过定期监测凝血功能及血小板计数,调整用药方案;每2个月做1次全面随访,包括有无出血、肝素诱导的血小板减少和复发事件的发生。【结果】两组均取得有效的抗凝效果,并且A组副作用发生率在各监测点明显低于B组(P<0.05),随访中发现两组DVT复发率无差异(P>0.05),但随着抗凝时间延长,两组患者出血发生率增加。在DVT复发患者中,髂股深静脉血栓形成者复发率最高,其次是股静脉、腘静脉。患者对应用A治疗方案的依从性较高。【结论】DVT患者院外继续应用LWMH抗凝效果可靠,用药安全性高,副作用较小,操作及监测简单,与应用VKA相比效益-风险比较高。     

Stapled diverticulectomy for solitary caecal diverticulitis

Caecal diverticulitis is an uncommon phenomenon in western countries. The clinical diagnosis is often difficult as it mimics other acute abdominal conditions like appendicitis, colitis or neoplasia. Diagnosis is often made at operation. Operative strategy has been controversial and there is no broad consensus emerging. We report the case of a 71-year-old woman, known to have chronic obstructive pulmonary disease, who presented acutely with right iliac fossa pain. A clinical diagnosis of appendicitis was made. At laparoscopy, a solitary, inflamed, gangrenous caecal diverticulum was found. A laparoscopic stapled diverticulectomy was performed. The patient made a steady post-operative recovery. Histology confirmed diverticulitis. We conclude that stapled diverticulectomy for solitary caecal diverticulitis is a safe and effective surgical strategy when confronted with this scenario.     

The Role of Free Radicals as Mediators of Endothelial Cell Injury in Hyperhomocysteinemia

Hyperhomocysteinemia has been suggested as a potent new risk factor for premature cardiovascular disease. Homocsyteine can induce endothelial cell injury but the mechanism is not understood. The purpose of this study was to evaluate the role of free radicals as potential causes of endothelial cell injury in a case-control study of obligate heterozygotes for cystathionine ß-synthase deficiency. Firstly, free radical production as measured by neutrophil chemiluminescence in obligate heterozygotes for cystathionine ß-synthase deficiency was compared with age- and sex-matched normal subjects. Secondly, the response of the cellular antioxidant system was examined by measuring the enzymes Superoxide dismutase and glutathione peroxidase, their cofactors (selenium, copper), vitamin E and vitamin A in heterozygotes and normal subjects. Analyses of neutrophil chemiluminescence, vitamin A and E, glutathione peroxidase, selenium and copper showed no difference between heterozygotes and controls. While Superoxide dismutase activity was higher in heterozygotes than normal subjects, the difference did not reach statistical significance and the hypothesis of excess free radical production as a mechanism of injury was not confirmed. However, further examination of Superoxide dismutase activity in a larger number of subjects would be of interest.     

Analysis of Ig and T-cell receptor genes in 40 childhood acute lymphoblastic leukemias at diagnosis and subsequent relapse: implications for the detection of minimal residual disease by polymerase chain reaction analysis

The rearrangement patterns of Ig and T-cell receptor (TcR) genes were studied by Southern blot analysis in 30 precursor B-cell acute lymphoblastic leukemias (B-ALLs) and 10 T-ALLs at diagnosis and subsequent relapse. Eight precursor B-ALLs appeared to contain biclonal/oligoclonal Ig heavy-chain (IgH) gene rearrangements at diagnosis. Differences in rearrangement patterns between diagnosis and relapse were found in 67% (20 cases) of precursor B-ALLs (including all eight biclonal/oligoclonal cases) and 50% (five cases) of T-ALLs. In precursor B-ALLs, especially changes in IgH and/or TcR-delta gene rearrangements were found (17 cases), but also changes in TcR-beta, TcR- gamma, Ig kappa, and/or Ig lambda genes (11 cases) occurred. The changes in T-ALLs concerned the TcR-beta, TcR-gamma, TcR-delta, and/or IgH genes. Two precursor B-ALLs showed completely different Ig and TcR gene rearrangement patterns at relapse, suggesting the absence of a clonal relation between the leukemic cells at diagnosis and relapse and the development of a secondary leukemia. The clonal evolution in the other 23 ALL patients was based on continuing rearrangement processes and selection of subclones. The development of changes in Ig and TcR gene rearrangement patterns was related to remission duration, suggesting an increasing chance of continuing rearrangement processes with time. These immunogenotypic changes at relapse occurred in a hierarchical order, with changes in IgH and TcR-delta genes occurring after only 6 months of remission duration, whereas changes in other Ig and TcR genes were generally detectable after 1 to 2 years of remission duration. The heterogeneity reported here in Ig and/or TcR gene rearrangement patterns at diagnosis and relapse might hamper polymerase chain reaction (PCR)-mediated detection of minimal residual disease (MRD) using junctional regions of rearranged Ig or TcR genes as PCR targets. However, our data also indicate that in 75% to 90% of ALLs, at least one major rearranged IgH, TcR-gamma, or TcR-delta band (allele) remained stable at relapse. We conclude that two or more junctional regions of different genes (IgH, TcR-gamma, and/or TcR-delta) should be monitored during follow-up of ALL patients for MRD detection by use of PCR techniques. Especially in biclonal/oligoclonal precursor B-ALL cases, the monitoring should not be restricted to rearranged IgH genes, but TcR-gamma and/or TcR-delta genes should be monitored as well, because of the extensive changes in IgH gene rearrangement patterns in this ALL subgroup.     

The intellectual abilities of early-treated individuals with pyridoxine-nonresponsive homocystinuria due to cystathionine beta-synthase deficiency

The pathological sequelae of untreated homocystinuria due to cystathionine -synthase deficiency include ectopia lentis, osteoporosis, thromboembolic events and mental retardation. They occur at a significantly higher rate with poorer mental capabilities (mean IQ = 57) in the untreated pyridoxine-nonresponsive individuals. The mental capabilities of 23 pyridoxine-nonresponsive individuals with 339 patient-years of treatment were assessed using age-appropriate psychometric tests and were compared to those of 10 unaffected siblings (controls). Of the 23 individuals, 19 were diagnosed through newborn screening with early treatment, two were late-detected and two were untreated at the time of assessment. Thirteen of the newborn, screened group who were compliant with treatment had no complications, while the remaining 6, who had poor compliance, developed complications. Good compliance was defined by a lifetime plasma free homocystine median < 11 mol/L. The newborn screened, good compliance group (n = 13) with a mean age of 14.4 years (range 4.4–24.9) had mean full-scale IQ (FIQ) of 105.8 (range 84–120), while the poorly compliant group (n = 6) with a mean age of 19.9 years (range 13.8–25.5) had a mean FIQ of 80.8 (range 40–103). The control group (n = 10) with mean age of 19.4 years (range 9.7–32.9) years had a mean FIQ of 102 (range 76–116). The two late-detected patients aged 18.9 and 18.8 years had FIQ of 80 and 102, while the two untreated patients aged 22.4 and 11.7 years had FIQ of 52 and 53, respectively. There was no statistical evidence of significant differences between the compliant, early-treated individuals and their unaffected siblings (controls) except for the FIQ, which was significantly higher than that of the unaffected siblings (p = 0.0397). These data, despite the relatively small numbers, suggest that early treatment with good biochemical control (lifetime plasma free homocystine median < 11 mol/L) seems to prevent mental retardation.     

Glucose-6-phosphate dehydrogenase variants: reexamination of G6PD Chicago and Cornell and a new variant (G6PD Pea Ridge) resembling G6PD Chicago

Two large and unrelated families were investigated for hereditary nonspherocytic hemolytic anemia associated with deficiency of erythrocyte glucose-6-phosphate dehydrogenase (G6PD). In both families, the kinetic and electrophoretic features of the G6PD variants resembled those of G6PD Chicago. Further investigation revealed that members of one of these families previously had been characterized as having the G6PD variants Chicago and Cornell. However, it is clear that each of these terms has been applied to the same variant in this single large kindred. In the second family, we describe a newly identified variant with unique characteristics, which we have designated G6PD Pea Ridge. G6PD Pea Ridge resembles G6PD Chicago but differs in electrophoretic mobility and in a few kinetic parameters. It exhibits an unusually high Ki for NADPH and thus appears to be insensitive to product inhibition. As other cases previously considered to be the Chicago variant become more fully characterized, this probably will be shown to be a heterogeneous group of variants.     

Effects of recombinant human granulocyte-macrophage colony-stimulating factor on intracellular pH in mature granulocytes

We studied the effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh) on the internal pH of granulocytes using the fluorescent probe BCECF. GM-CSFrh did not directly alter the resting pH of granulocytes isolated from the peripheral blood; however, when the cells were preincubated for 90 minutes with the growth factor and then activated with the chemotactic peptide N-formyl met leu phe (fMLP), they exhibited both an acceleration in the initial rate of acidification and a marked delay in realkalinization. The kinetic changes both in initial acidification and in subsequent realkalinization induced by GM-CSFrh priming were not prevented by protein synthesis inhibitors and were observed in granulocytes harvested from patients with both sex-linked and autosomal recessive chronic granulomatous disease (CGD). By directly quantitating H+ ion secretion, by monitoring the effects of sodium repletion on intracellular pH, and through use of the sodium channel inhibitors amiloride and dimethyl amiloride and the Na+/K+-ATPase inhibitor ouabain, we showed that the altered kinetics of intracellular acidification and alkalinization following fMLP stimulation of GM-CSFrh- primed granulocytes could not be accounted for by changes in transmembrane proton exportation regulated by the Na+/H+ antiport channel. Although the initial acidification following fMLP was abrogated by 2-deoxy-D-glucose in both GM-CSFrh-pretreated and GM-CSFrh- untreated granulocytes, retardation of the subsequent phase of alkalinization was observed in GM-CSFrh-primed cells even after inhibition of both glycolytic and mitochondrial metabolism. Our data indicate that the increased cytosolic acidification following fMLP stimulation in granulocytes "primed" with GM-CSFrh does not result from disordered proton excretion but instead from increased release of intracellular free acid which is only partially coupled to glucose catabolism or to the generation of superoxide anion (O2-).     

Demonstration of reversible priming of human neutrophils using platelet- activating factor

Exposure of neutrophils to agents such as lipopolysaccharide, tumor necrosis factor-alpha (TNF-alpha), and the granulocyte-macrophage colony-stimulating factor causes a major upregulation of subsequent agonist-induced NADPH oxidase activation. This priming effect is a prerequisite for neutrophil-mediated tissue damage and has been widely considered to be an irreversible process. We have investigated the potential for neutrophils to recover from a priming stimulus by studying the effects of platelet-activating factor (PAF). PAF did not stimulate respiratory burst activity directly, but caused a rapid (maximal at 10 minutes) and concentration-dependent (EC50 50.2 nmol/L) increase in N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated superoxide anion release. At time-points > 10 minutes, this priming effect spontaneously declined, with return to basal levels of fMLP- stimulated superoxide anion generation by 120 minutes. An identical priming time-course was observed with N-methyl carbamyl PAF, a nonmetabolizable analogue of PAF, indicating that the transient nature of PAF-induced priming was not secondary to PAF metabolism. Two structurally diverse PAF receptor antagonists (UK-74,505 and WEB 2086), added 10 minutes after PAF addition, increased the rate of decay of the priming effect. In contrast, TNF-alpha-induced priming, which was of a similar magnitude to that observed for PAF, was slower to evolve (maximal at 30 minutes) and remained constant for at least 120 minutes. The reversible nature of PAF-induced priming was confirmed by demonstrating that PAF-, but not TNF-alpha-, induced cell polarization (shape change) and CD11b-dependent neutrophil binding of albumin-coated latex beads was also transient, with return to basal, unstimulated levels by 120 minutes. Furthermore, cells that had spontaneously deprimed following PAF exposure retained their capacity to be fully reprimed by a subsequent addition of either PAF or TNF-alpha. These data imply that neutrophil priming is not an irreversible event: the demonstration of a cycle of complete priming, depriming, and repriming offers the potential for functional recycling of neutrophils at sites of inflammation.     

Molecular and cellular effects of antisickling concentrations of alkylureas

Alkylureas are capable of inhibiting sickling in vitro and the gelation of solutions of hemoglobin S at concentrations between 0.05 and 0.1 M with increasing effectiveness that is directly proportional to the length of the alkyl chain (butyl greater than propyl greater than ethyl greater than methyl). 6The inhibitory effect is independent of pH between 6.5 and 7.5 and is a process driven by entropy. The alkylureas at concentrations of 0.1 M have minimal effects on several erythrocyte functions. Oxygen equilibria, osmotic fragility, reduced glutathione content, and glutathione reductase activity are totally unaffected, while pyruvic kinase activity is decreased only by butylurea by about 20%, and glucose-6-phosphate dehydrogenase activity is decreased progressively to a maximum of 30% in direct proportion to the length of the alkyl chain. Alkylureas not only inhibit sickling but are also capable of desickling erythrocytes that have been maintained in the deoxygenated state. They have little effect on several erythrocyte functions at antisickling concentrations, but their toxicity must be evaluated before they can be examined as potential therapeutic agents for the treatment or prevention of acute episodes in sickle cell anemia.