Haemostatic measurements in childhood nephrotic syndrome

Blood coagulation and platelet aggregation were assessed in children, with nephrotic syndrome who were divided into the following groups: (1) relapse without treatment; (2) relapse on steroids; (3) early remission; (4) late remission and (5) steroid resistant. The renal histological findings were also recorded. Plasma antithrombin III (ATIII) levels were markedly reduced in groups 1 and 2, below normal in group 3 and were normal in groups 4 and 5. There was significant urinary loss of AT III in groups 1 and 2 as well as in group 5. Plasma fibrinogen fluctuations exhibited the expected negative correlations with plasma AT III. Reptilase time showed significant prolongation in groups 1, 2 and 3, and was near normal in groups 4 and 5. Platelet aggregation in response to arachidonic acid exhibited aggregation followed by disaggregation in groups 1, 2, 4 and 5, and was normal in group 3. Hyperaggregation in response to decreasing doses of ADP was noted in all patient groups as well as controls with no relationship to serum albumin levels. Aggregation responses to collagen and ristocetin were normal. It is concluded that: 1. The fluctuations in AT III levels in childhood nephrotic syndrome are determined by the response to steroids and not by the renal histology per se. 2. An acquired fibrin polymerization defect (dysfibrinogenaemia) and an abnormality of the prostaglandin pathway of platelet activation, both reversible, are yet other haemostatic abnormalities in childhood nephrosis. 3. The discrepancies in the literature on haemostatic parameters, specially AT III in childhood nephrosis, would not have arisen if their fluctuation in relation to steroid therapy as well as the renal histological features of nephrotic syndrome had been documented simultaneously.     

Disturbances of anticoagulation and fibrinolytic systems in monoclonal gammopathies-another mechanism of M-protein interference with hemostasis

Monoclonal gammopathies (MG) may be associated with unique monoclonal immunoglobulin (MIg)-induced disturbances of either primary hemostasis or plasma coagulation. We have investigated the possible interference of MIg with antithrombotic systems in 49 patients with MG. Although an increase of tissue-type plasminogen activator (t-PA) activity was the most frequent abnormality in our group, defect of anticoagulation factors was found in 26.5% of patients. The relationship between MIg type and concentration and frequency of antithrombotic factor abnormalities was not found. The risk of venous thrombosis was higher in patients with the defect in comparison with the unaffected group (46% vs. 22%), but the difference was not statistically significant. Bleeding complications were markedly less frequent in the group of patients with defect of anticoagulation mechanisms (0% vs. 17%). In conclusion, we have found abnormalities in anticoagulation and/or fibrinolytic system, analogous to well-known disturbances of hemostatic mechanisms, in more than a quarter of patients with MG. The interference of M-protein with antithrombotic pathways is supposed to be another mechanism of secondary deficiencies of antithrombin III (AT III), protein C (PC), protein S (PS), plasminogen and APC resistance. Together with other factors, it could contribute to higher risk of thromboembolism in myeloma patients.     

胰激肽原酶对大鼠糖尿病性心肌病的影响

目的:探讨糖尿病性心肌病的发生、发展并试用胰激肽原酶干预治疗,为糖尿病性心肌病的防治提供参考.方法: 建立3个月、6个月糖尿病大鼠模型(糖尿病组)放免法测定糖尿病组血浆及心肌局部血管紧张素II(AT II)、测定心脏重量指数、dp/dtmax比值,与对照组、胰激肽原酶干预组相比较.结果: 糖尿病组心肌局部AT II 6个月明显增高,血浆AT II 3个月、6个月持续增高;心脏重量指数3个月、6个月持续高于对照组;心脏dp3个月、6个月进行性下降,差异具有显著性.胰激肽原酶干预组心肌局部和血浆AT II变化不明显,心脏重量指数明显下降,血压明显下降; dp/dtmax, -dp/dtmax均有所上升.结论:AT II在糖尿病性心肌病模型的发生中起重要作用,发病早期应用胰激肽原酶在一定程度上可阻抑糖尿病心肌病的发展进程.     

IL-1β对大鼠下丘脑室旁核神经元放电活动的影响

目的研究白细胞介素-1β（IL-1β）对室旁核神经元自发电活动的影响，并探讨其机制。方法采用细胞外记录单位放电技术，在大鼠下丘脑脑片上观察IL-1β对室旁核神经元自发电活动的影响，以及氯沙坦对IL-1β诱发电活动的影响。结果在59个PVN神经元放电单位给予IL-1β（1×10^-7mol／L）后，有46个（78％）放电单位放电频率明显增加（P〈0．01）；在对IL-1β（1×10^-7 mol／L）呈兴奋反应的12个神经元放电单位中，用氯沙坦（1×10^-6mol／L）灌流后，除2个放电频率无明显变化外，其余10个单位放电频率显著低于灌流氯沙坦前的放电频率（P〈0．05）。结论IL-1β能兴奋下丘脑室旁核神经元自发放电，可能与血管紧张素1型受体（AT1R）有关。     

Pulmonary arterial hypertension: the key role of echocardiography

Given the nonspecific nature of its early symptoms and signs, pulmonary arterial hypertension (PAH) is often diagnosed in its advanced stages. Although clinical assessment is essential when initially evaluating patients with suspected PAH, echocardiography is a key screening tool in the diagnostic algorithm. It not only provides an estimate of pulmonary pressure at rest and during exercise, but it may also help to exclude any secondary causes of pulmonary hypertension, predict the prognosis, monitor the efficacy of specific therapeutic interventions, and detect the preclinical stage of the disease.     

Functional significance of a deep intronic mutation in the ATM gene and evidence for an alternative exon 28a

Screening for ATM mutations is usually performed using genomic DNA as a template for PCR amplification across exonic regions, with the consequence that deep intronic sequences are not analyzed. Here we report a novel pseudoexon-retaining deep intronic mutation (IVS28-159A>G; g.75117A>G based on GenBank U82828.1) in a patient with ataxia-telangiectasia (A-T), as well as the identification of a previously unrecognized alternative exon in the ATM gene (exon 28a) expressed in lymphoblastoid cell lines (LCL) derived from normal individuals. cDNA analysis using the A-T patient's LCL showed the retention of two aberrant intronic segments of 112 and 190 nt between exons 28 and 29. Minigenes were constructed to determine the functional significance of two genomic changes in the region of aberrant splicing: IVS28-193C>T (g.75083C>T) and IVS28-159A>G, revealing that: 1) the first is a polymorphism; 2) IVS28-159A>G weakens the 5' splice site of the alternative exon 28a and activates a cryptic 5' splice site (ss) 83 nt downstream; and 3) wild-type constructs also retain a 29-nt segment (exon 28a) as part of both the 112- and 190-nt segments. Maximum entropy estimates of ss strengths corroborate the cDNA and minigene findings. Such mutations may prove relevant in planning therapy that targets specific splicing aberrations.     

Characterization of two novel mutations of the antithrombin gene observed in Japanese thrombophilic patients

We investigated the molecular basis of reduced functional levels of antithrombin (AT) in two individuals suffering from thromboembolic events. In each case direct sequencing of amplified DNA revealed 13,260-13,262 del in one patient and 2511C>A in the other patient, predicting a heterozygous E381del and P16H, respectively. Both patients had no 20210A allele and factor V Leiden mutation. To understand the molecular mechanism responsible for antithrombin deficiency, stable expression experiments were performed using HEK293 cells transfected with the expression vector containing the wild-type or the mutated recombinant cDNA. In these experiments, the media levels of the two mutated antithrombins were the same as that of wild type, but the specific activity of the E381del mutant decreased significantly compared with that of wild type. These results showed that the E381del mutation was responsible for type II deficiency, whereas the other mutation, P16H, did not produce any definite abnormality which could contribute to antithrombin deficiency.     

Angiotensin II type 2 receptor effect on microvascular hydraulic permeability

BACKGROUND: Angiotensin II (Ang II) is a potent vasoconstrictor that modulates microvascular permeability. Angiotensin II type 1 (AT1) and type 2 (AT2) receptors have been described with subsequent development of their respective antagonists. We hypothesized that the AT2 receptor modulates microvascular permeability. MATERIALS AND METHODS: Hydraulic permeability (L(p)) was measured in rat mesenteric venules using the Landis micro-occlusion technique. Following baseline L(p) measurements, paired measures of microvessel L(p) were obtained after perfusion with a test solution. The test solutions consisted of the AT2 receptor agonist CGP42112A at 10 microm (n = 6), 100 microm (n = 6), and 200 microm (n = 6), as well as the AT2 receptor antagonist PD-123319 at 3 microm (n = 6), 30 microm (n = 6), 300 microm (n = 6), and 600 microm (n = 6). RESULTS: From mean baseline L(p) of 0.99 +/- 0.03, 100 microm CGP42112A decreased L(p) to 0.76 +/- 0.02 (P = 0.005), and 200 microm CGP42112A decreased L(p) to 0.61 +/- 0.02 (P < 0.001). From mean baseline L(p) of 0.90 +/- 0.05, PD-123319 increased L(p) at 30 microm to 1.60 +/- 0.2 (P = 0.003), at 300 microm to 2.28 +/- 0.3 (P = 0.008), and at 600 microm to 4.30 +/- 0.9 (P = 0.03). Units for L(p) are mean +/- SEM x 10(-7) cm s(-1) cmH(2)O(-1). CONCLUSION: AT2 activation decreased L(p), while AT2 blockade increased L(p). These changes in L(p) may be explained by (1). a permeability-decreasing effect of the AT2 receptor that is induced by AT2 activation and inhibited by AT2 blockade; and/or (2). a permeability-increasing effect of the AT1 receptor observed during AT2 blockade and selective AT1 activation by endogenous locally released Ang II. These mechanisms would support the theories that the AT1 receptor increases microvascular permeability, while the AT2 receptor decreases microvascular permeability.     

Expression of AT1amRNA in rat hepatic stellate cells and its effects on cell growth collagen production

Activated hepatic stellate cells (HSCs) play important roles in hepatic fibrosis. Studies on HSCs activation in vitro have shown that this process is regulated by a wide variety of growth factors and cytokines。 Recent data indicate that Ang Ⅱ is responsible for the mechanisms of myocardial fibrosis and kidney fibrosis; but there are only few reports on hepatic fibrosis.