力竭性运动对大鼠血浆心钠素及心肌血供的影响

目的：观察不同训练程度大鼠力竭性运动后血浆心钠素含量及心肌缺血情况，探讨力竭性运动对大鼠心脏内分泌以及心肌血供的影响。方法：实验于2006—10/12在武汉体育学院细胞与分子生物学实验室完成。选择SD大鼠16只，按随机数字表法分为3组，安静对照组（n=4）笼内生活，自由饮食；游泳力竭组（n=6）适应性喂养1周后进行一定的适应性游泳训练；长期耐力训练游泳力竭组（n=6）训练8周，6次/周。8周后，后两组大鼠进行力竭性运动，运动后取大鼠血浆，采用放射免疫法测定心钠素含量；取心肌组织，制作光镜切片，采用Nagar-Olsen特殊染色法检测心肌缺血情况。结果：16只大鼠全部进入结果分析。①在经过8周的运动训练后，游泳力竭组、长期耐力训练游泳力竭组大鼠血浆心钠素含量显著高于安静对照组（P〈0．05，〈0．01）；长期耐力训练游泳力竭组大鼠血浆心钠素含量显著高于游泳力竭组（P〈0．05）。②游泳力竭组大鼠心肌组织缺血较为严重；而长期耐力训练游泳力竭组大鼠心肌组织与安静对照组相比，也有缺血现象发生，但没有游泳力竭组严重。结论：力竭性运动会造成大鼠心血管内分泌活性物质心钠素的失调，并造成心肌组织缺血；长期耐力游泳训练可以使大鼠心脏结构及功能产生一定的适应性改变。     

The neutrophil gelatinase-associated lipocalin (NGAL), a NF-kappaB-regulated gene, is a survival factor for thyroid neoplastic cells

NF-κB is constitutively activated in primary human thyroid tumors, particularly in those of anaplastic type. The inhibition of NF-κB activity in the human anaplastic thyroid carcinoma cell line, FRO, leads to an increased susceptibility to chemotherapeutic drug-induced apoptosis and to the blockage of their ability to form tumors in nude mice. To identify NF-κB target genes involved in thyroid cancer, we analyzed the secretome of conditioned media from parental and NF-κB-null FRO cells. Proteomic analysis revealed that the neutrophil gelatinase-associated lipocalin (NGAL), a protein involved in inflammatory and immune responses, is secreted by FRO cells whereas its expression is strongly reduced in the NF-κB-null FRO cells. NGAL is highly expressed in human thyroid carcinomas, and knocking down its expression blocks the ability of FRO cells to grow in soft agar and form tumors in nude mice. These effects are reverted by the addition of either recombinant NGAL or FRO conditioned medium. In addition, we show that the prosurvival activity of NGAL is mediated by its ability to bind and transport iron inside the cells. Our data suggest that NF-κB contributes to thyroid tumor cell survival by controlling iron uptake via NGAL.     

Effect of natural killer cells on syngeneic bone marrow: in vitro and in vivo studies demonstrating graft failure due to NK cells in an identical twin treated by bone marrow transplantation

Bone marrow transplantation for severe idiopathic aplastic anemia was undertaken in a patient, using his monozygotic twin brother as the donor. In spite of the use of syngeneic bone marrow, failure of engraftment occurred on two occasions. In vitro studies demonstrated that natural killer (NK) cells from the recipient markedly inhibited the growth of donor bone marrow granulocyte progenitor cells. On a third attempt, successful bone marrow engraftment was achieved following high-dose cyclophosphamide, which has previously been shown to be inhibitory to NK cells. We conclude that NK cell activity may play an important role in bone marrow failure as well as being responsible for at least some cases of aplastic anemia.     

Plasminogen activator inhibitor: a regulator of ancrod-induced fibrin deposition in rabbits

Plasma levels of a fast-acting plasminogen activator inhibitor (PAI), which neutralizes both tissue plasminogen activator (t-PA) and urokinase, are markedly increased in endotoxin-treated rabbits. The ability of this inhibitor to prevent the fibrinolysis that occurs after a thrombogenic stimulus was investigated in a rabbit model. Normal and endotoxin-treated male New Zealand rabbits were infused with ancrod, an enzyme that causes noncrosslinked fibrin formation in vivo. Ancrod stimulated t-PA activity by 90% in normal rabbits and caused hypofibrinogenemia but did not increase PAI levels or induce fibrin deposition in target organs. Rabbits injected with endotoxin (10 micrograms/kg) showed an increase in PAI from less than 1 to 32 U/mL 4 hours later. When ancrod was infused at this time, 90% of the rabbits developed renal fibrin thrombi. Fibrin deposition was recorded in 40% of the rabbits that received a lower dose of endotoxin (1.0 microgram/kg) and had a PAI level of 14 U/ml at the time of ancrod infusion 4 hours later. Fibrin deposition did not occur in the endotoxin-treated rabbits that received normal saline. These data suggest that high levels of PAI inhibit fibrinolysis in vivo, thereby promoting fibrin clot deposition following a thrombogenic stimulus.     

Cogan's syndrome with Takayasu's arteritis

Cogan's syndrome may be associated with large-vessel arteritis. We describe a patient with ocular inflammation, sensorineural hearing loss and arm claudication in whom a diagnosis of 'atypical' Cogan's syndrome and Takayasu's arteritis was made. All symptoms resolved with treatment.      

Prevalence of human T-cell leukemia/lymphoma virus (HTLV) type II infection among high-risk individuals: type-specific identification of HTLVs by polymerase chain reaction

The extent of human T-cell leukemia/lymphoma virus type II (HTLV-II) infection and its rate of spread have been difficult to determine owing to the serological cross-reactivity between HTLV-I and HTLV-II. The present study overcame this problem by directly detecting type-specific proviral sequences by means of the polymerase chain reaction (PCR) and liquid hybridization. Screening was performed on a cohort of primarily white intravenous drug abusers (IVDAs), and individuals of other behaviorally defined risk groups from the New York City area. Eleven percent (19 of 169) of the individuals in these high-risk groups were determined by PCR to have HTLV-II proviral infections. One of these patients displayed an exfoliative erythrodermatitis. Thirteen of the 19 subjects were positive in an HTLV-II enzyme-linked immunosorbent assay (ELISA). The remaining six individuals, although negative in the HTLV- II ELISA, were confirmed as HTLV-II positive by analyzing their DNA with a second HTLV-II-specific primer detector system. Four additional individuals were reactive in the HTLV-II ELISA but were PCR-negative for HTLV-II. PCR analysis for HTLV-I revealed that all four were positive for that virus. Thirty-seven percent (seven of 19) of the HTLV- II PCR-positive subjects were also PCR-positive for HTLV-I, and 84% (16 of 19) of the HTLV-II positive individuals were infected with human immunodeficiency virus (HIV-1). Six individuals were triply infected with HTLV-I, HTLV-II, and HIV-1.     

The site of the breakpoint within the bcr is a prognostic factor in Philadelphia-positive CML patients [see comments]

The Philadelphia (Ph1) chromosome, characteristic of chronic myelogenous leukemia (CML), arises from a reciprocal translocation between chromosomes 9 and 22. The site of the breakpoint on chromosome 22 is within a small region called the breakpoint cluster region (bcr). We have mapped the breakpoint within the bcr in peripheral blood leukocyte DNA from 22 Ph1-positive CML patients. No correlation between the site of the breakpoint and the clinical phase of the disease was found. However, a striking correlation between the site of the breakpoint and the length of time between presentation and onset of acute phase was observed: on average, patients with a 5' break-point had a fourfold longer chronic phase (median, 203 weeks) than those with a 3' breakpoint (median, 52 weeks).