Analysis of Killer Cell Activities in Epstein-Barr Virus Infections

Using spontaneously established autologous lymphoblastoid B cell lines (LCL), killer cell activities were studied in children with severe infectious mononucleosis (IM), chronic IM, and acute IM, and compared with those in EBV-seropositive normal controls. Natural killer (NK) cell activity of fresh peripheral blood mononuclear cells (PBMC) was normal in acute IM patients, but it was low in four of six patients with severe or chronic IM. Recombinant inter-leukin 2 (rIL-2)-activated PBMC from normal controls showed lymphokine-activated killer (LAK) cell activity against the respective autologous LCL. The levels of LCL lysis by LAK cells were significantly higher in acute IM patients, lower in chronic IM patients, and much lower in severe IM patients. In contrast to the fact that PBMC stimulated in vitro with autologous LCL (IVS cells) from normal controls and acute IM patients showed potent killing of autologous LCL, IVS cells from severe or chronic IM patients showed lower levels of LCL lysis, which were markedly augmented in three patients by rIL-2 addition to the cultures. These killer cell dysfunctions appear to be responsible for the severe or chronic course of EBV infection.     

EFFECTS OF p53 GENE THERAPY COMBINED WITH CYCLOOXYGENASE-2 INHIBITOR ON CYCLOOXYGENASE-2 GENE EXPRESSION AND GROWTH INHIBITION OF HUMAN LUNG CANCER CELLS

Background Gene therapy by adenovirus-mediated wild-type p53 gene transfer has been shown to inhibit lung cancer growth in vitro, in animal models, and in human clinical trials. The antitumor effect of selective cyclooxygenase （COX）-2 inhibitors has been demonstrated in preclinical studies. However, no information is available on the effects of p53 gene therapy combined with selective COX-2 inhibitor on COX-2 gene expression and growth inhibition of human lung cancer cells. Methods We evaluated the effects of recombinant adenovirus-p53 （Adp53） gene therapy combined with selective CADX-2 inhibitor on the proliferation, apoptosis, cell cycle arrest of human lung adenocarcinoma A549 cell line, and the effects of tumor suppressor exogenous wild type p53 on COX-2 gene expression. Results Ad-p53 gene therapy combined with selective COX-2 inhibitor celecoxib shows significant synergistic inhibition effects on the growth of human lung adenocarcinoma A549 cell line. Exogenous p53 gene can suppress COX-2 gene expression. Conclusions Significant synergistic inhibition effects of A549 cell line by the combined Ad-p53 and selective COX-2 inhibitor celecoxib may be achieved by enhancement of growth inhibition, apoptosis induction and suppression of COX-2 gene expression. This study provides first evidence that the administration of p53 gene therapy in combination with COX-2 inhibitors might be a new clinical strategy for the treatment or prevention of NSCLC.     

Initial experience with carbon dioxide laser laparoscopy

Adhesions and endometriosis are commonly encountered among patients presenting with pelvic or lower abdominal pain and also in a significant proportion of infertile patients. Laparoscopic investigation is usual in patients with these problems, and it has been possible to perform endoscopic surgery with special scissors and electrodiathermy. These methods can cause troublesome bleeding, and the diathermy produces high temperatures which can be hazardous if used in the vicinity of the bowel. The carbon dioxide laser can be used endoscopically to vaporize deposits of endometriosis and adhesions with great precision and virtually no bleeding. One hundred consecutive patients with endometriosis or adhesions were treated with the CO₂ laser laparoscope and followed up for at least a year. Seventy-five per cent of patients with pain due to endometriosis were cured, and 68% of patients were better after laser laparoscopic adhesiolysis. Pregnancy rate in the previously infertile group with endometriosis was 64%. There were no complications due to the intra-abdominal use of CO₂ laser energy under endoscopic control, although there is a need for a controlled trial. It appears that in the hands of an experienced laparoscopist this technique is safe and effective.     

α_2受体阻滞后肾上腺素诱导的心衰病人血小板的聚集功能

先前的研究表明血小板α_2受体变化表征交感神经突触前α_2受体的变化。为了解心衰病人血小板α_2受体功能状况,我们观察了10例Ⅲ、Ⅳ级心功能的心衰病人及10例配对正常人由肾上腺素诱导的血小板聚集率在α_2受体阻滞前后的变化。结果表明肾上腺素诱导的血小板聚集率在两组无显著性差异,但应用α_2阻滞剂Rauwolscine(0.25mg/L)后,0.25,0.5,1.0mg/L E诱导的心衰病人血小板聚集率显著低于对照组,提示血小板α_2受体在心衰时有数量的减少或(和)功能的降低,表征交感神经突触前NE释放的负反馈机制被抑制。     

塞来昔布对大鼠化学性乳腺癌的抑制作用及机制

目的 观察环氧化酶-2(cyclooxygenase-2,COX-2)选择性抑制剂塞来昔布对化学致癌剂7,12-二甲基苯蒽(7,12-dimethybenz[a]anthracene,DMBA)化学诱发的大鼠乳腺癌的抑制作用并探讨其机制.方法 将DMBA油剂灌胃复制大鼠乳腺癌模型,大鼠分为对照组(24只)和实验组(25只),观察塞来昔布对大鼠乳腺癌的抑制作用,并采用基因芯片技术了解治疗后2组肿瘤的基因表达谱差异.结果 实验组塞来昔布处理后乳腺肿瘤的数目、直径、体积分别为(2.56±1.26)个、(1.162±0.355)cm、(1.967±1.725)cm.;明显小于实验前的(3.40±1.22)个、(1.948±0.481)cm、(8.794±6.389)cm3;明显小于对照组(3.88±1.73)个、(2.231±0.736)cm、(10.268±5.447)cm3,差异有显著性意义(均P＜0.01).对照组COX一2蛋白表达为62.5%(15/24),实验组COX-2蛋白表达为36.0%(9/25),差异有显著性意义(P＜O.05).基因表达谱显示两组之间表达丰度差异2倍及以上的基因共有243条,其中表达上调2倍或以上的基因片段124条,表达下调2倍或以上的基因片段119条,发现功能不明的新基因6条,其中表达上调的4条.结论 塞来昔布能抑制DMBA诱发的大鼠乳腺癌进展,其机制和多种基因改变有关.     

胰岛素样生长因子2(Igf2)研究进展

胰岛素样生长因子2(insulin-like growthfactors II,Igf2),又称生长调节素A,是一个单链多肽分子,与胰岛素样生长因子1(insulin-like growth factors I,Igf1)在氨基酸组成上具有同源性,并且二者都与胰岛素原(proinsulin)具有同源性[1]。由于Igf2是一个在细胞增殖、分化、程序性细胞死亡和转化中具有重要作用的因子,对个体生长、发育具有重要作用,人类许多疾病的发生发展都与该基因的印迹调控异常有关。因此,近年来人们对Igf2进行广泛的研究,并取得了长足的进展。     

Persistent platelet activation in patients with type 2 diabetes treated with low doses of aspirin

BACKGROUND: The percentage of diabetic patients who do not benefit from the protective effect of aspirin is larger than in other populations at cardiovascular risk. OBJECTIVE: We compared the ability of aspirin to suppress TxA2 and platelet activation in vivo, in type-2 diabetics vs. high-risk non-diabetic patients. METHODS: Urinary 11-dehydro-TXB2, plasma sCD40 L, and sP-selectin were measured, together with indices of low-grade inflammation, glycemic control, and lipid profile, in 82 patients with type-2 diabetes and 39 without diabetes, treated with low doses of aspirin. RESULTS: Urinary 11-dehydro-TxB2, plasma sCD40L and sP-selectin were significantly higher in diabetics than in controls: [38.9 (27.8-63.3) vs. 28.5 (22.5-43.9) ng mmol(-1) of creatinine, P = 0.02], [1.06 (0.42-3.06) vs. 0.35 (0.22-0.95) ng mL(-1); P = 0.0001], [37.0 (16.8-85.6) vs. 20.0 (11.2-35.6) ng mL(-1), P = 0.0001], respectively. The proportion of individuals with diabetes increased across quartiles of 11-dehydro-TxB2, sCD40L, and sP-selectin, with the highest quartiles of 11-dehydro-TxB2, sCD40L and sP-selectin, including 66%, 93.3%, and 93.3% of individuals with diabetes. Markers of platelet activation positively correlated with indices of glycemic control but not with markers of low-grade inflammation. CONCLUSIONS: Platelet dysfunction associated with insufficient glycemic control, may mediate persistent platelet activation under aspirin treatment.     

Effects of adenosine 5’-triphosphate, uridine 5’-triphosphate, adenosine 5’-tetraphosphate and diadenosine polyphosphates in guinea-pig taenia caeci and rat colon muscularis mucosae

The functional effects of adenosine 5’-triphosphate (ATP), uridine 5’-triphosphate (UTP), adenosine 5’-tetraphosphate (AP₄) and the diadenosine polyphosphates P₁,P₃-diadenosine triphosphate (Ap₃A), P₁,P₄-diadenosine tetraphosphate (Ap₄A) and P₁,P₅-diadenosine pentaphosphate (Ap₅A) were studied in two isolated smooth muscle preparations thought to contain P_2Y (P2Y₁) receptors, the guinea-pig taenia caeci (which relaxes to ATP) and the rat colon muscularis mucosae (which contracts to ATP). In addition, the breakdown of these compounds by the rat colon muscularis mucosae was investigated by high pressure liquid chromatography. In the guinea-pig taenia caeci all the purine nucleotides caused relaxation with a potency order of Ap₃A=Ap₄A> ATP>AP₄=Ap₅A, and these relaxations were antagonised by suramin with apparent pA₂ values in the region of 5, consistent with activation of a P2Y₁ receptor. In the rat colon muscularis mucosae the nucleotides caused contraction with a potency order of Ap₃A = Ap₄A>ATP=AP₄ =Ap₅A >UTP. However, while suramin (100 μM) inhibited responses to ATP and UTP at all concentrations of agonist, it only inhibited contractions induced by the higher concentrations of AP₄, Ap₃A and Ap₄A and had little effect on contractions induced by Ap₅A. A higher concentration of suramin (1 mM) enhanced contractions induced by ATP but greatly inhibited those induced by UTP and had no effect on responses to the other agonists. The A₁ adenosine receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 10 nM) had no effect on responses to ATP or UTP but inhibited responses to Ap₃A, Ap₄A, Ap₅A and AP₄. A combination of suramin (1 mM) and DPCPX (10 nM) almost abolished responses to all the agonists. ATP and UTP were rapidly degraded by the rat colon muscularis mucosae while AP₄, Ap₃A, Ap₄A and Ap₅A were degraded more slowly, and the major product detected after breakdown of the purine nucleotides was inosine rather than adenosine. The breakdown of all the nucleotides was inhibited by suramin (1 mM), although this inhibition did not achieve statistical significance in the case of ATP. These results show that while the diadenosine polyphosphates appear to act as P2 agonists in the taenia caeci, in the rat colon muscularis mucosae their major action is via adenosine A₁ receptors rather than via P2 receptors. In addition, although they are more stable than ATP or UTP, their action in this tissue is clearly affected by their degradation which complicates the effects of suramin. Received: 23 March 1998 / Accepted: 29 June 1998