16层螺旋CT及其三维重建与多平面重组在胫骨平台骨折诊断中的应用

目的探讨16层螺旋CT(16层SCT)及其三维重建(3-D)与多平面重组(MPR)在胫骨平台骨折诊断中的应用价值。方法39例胫骨平台骨折病例经膝关节常规X线平片检查后，采用16层SCT进行膝关节的多层面螺旋CT扫描，在工作站上作3D及MPR影像后处理，就胫骨平台骨折的平片与16层SCT影像进行比较及综合分析。结果39例胫骨平台骨折中，X线平片漏诊1例髁间隆突骨折、1例内髁骨折及1例双髁骨折，此3例(7．69％)平片漏诊的骨折均为16层SCT予以诊断。16层SCT的3-D影像可清晰显示胫骨平台骨折的立体形态；MPR影像则可明确显示胫骨平台内部的骨质损伤情况如骨折的具体部位、关节面碎裂及塌陷程度、骨折移位距离。结论16层SCT能够显示X线平片难于诊断的胫骨平台隐匿性骨折；3-D及MPR成像技术十分有利于全面观察胫骨平台骨折的形态变化，是16层SCT横轴位扫描的重要补充。     

无溶剂体系合成1,3-甘油二酯用脂肪酶的筛选及其酯化性质

对不同来源的脂肪酶进行了系统的筛选,并根据位置专一性的差别将脂肪酶分为1,3 特异的、1,3 选择性和非选择性的3类.采用LipozymeRMIM在无溶剂系统中催化甘油、脂肪酸合成1,3 sn 甘油二酯.研究表明脂肪酸、底物醇种类、温度、水分活度对LipozymeRMIM的活力有明显的影响.     

Immunogenicity study of low-dose administration of hepatitis B virus vaccine in newborn infants: A cost reduction trial

Different doses of hepatitis B virus vaccine—prepared by Korea Green Cross Corporation, were given to healthy infants born to HBsAg-negative mothers at birth, 1 and 6 months of age. A dose of 2 μg was administered intradermally in Group A and, in the three other groups, the vaccine was given intramuscularly (i.m.). An adequate follow-up observation was possible for 9 months after birth in 22, 25, 23 and 21 infants in Groups A, B, C and D, respecvely.
Group C (5 μg, i.m.) produced seroconversion most rapidly, showing the highest rate (96%) at 9 months of age. The lowest seroconversion rate (5%) was found at the age of 1 month in Group A subjects, but the rate increased to 91% after a booster dose was given at 6 months of age.
While it can be concluded that a 5 μg i.m. dose of vaccine at 0, 1 and 6 months of age is optimum for the immunization of infants in efficacy and economy, a 2 μg intradermal dose can also be considered as an immunogenic and economical regimen, though the immune response is slower and a special technique is required for immunization.     

Investigation of the negative chronotropic action of SK&F 86466 in the pithed normotensive rat

SK&F 86466, 6-chloro-3-methyl-2,3,4,5-tetrahydro-1-H-3-benzazepine, is a potent and selective antagonist of the α₂-adrenoceptor in vitro. This compound produced a small pressor response accompanied by a marked bradycardia when administered i.v. to the pithed normotensive rat. The pressor response was not affected by reserpine treatment, pretreatment with α- or β-adrenoceptor antagonists, atropine, or hexamethonium. The bradycardia was markedly reduced by bilateral vagotomy and pretreatment with atropine and attenuated by hexamethonium. The negative chronotropic action of SK&F 86466 was abolished by a combination of vagotomy and atropine. Mediation of the bradycardia by a baroreceptor reflex was ruled out by the observations that a lack of change in heart rate was associated with the vasopressor response to phenylephrine in the pithed rat pretreated with propranolol. It is concluded that the negative chronotropic action of SK&F 86466 in the pithed rat is mediated indirectly by activation of the cholinergic innervation of the heart.     

LOGIQ 400B超机疑难故障维修一例

分析了GELOGIQ 400B超机不能启动的故障，经对电源、主板、硬盘的维修，机器恢复正常。     

Synthesis of a new carrier for immunization: polytuftsin

Sequential poly(Arg-Thr-Lys-Pro) consisting mainly of the repeat of tuftsin Thr-Lys-Pro-Arg was synthesized by condensing the p-nitrophenyl ester of Arg(HCI)-Thr-Lys-(2-CI-Z)-Pro in the presence of HOBt . Two haptenic sequences of the Pre-S region of hepatitis B virus antigen (10–26 and 39–55) were prepared by solid phase and coupled to polytuftsin via glutaraldehyde. The peptides, either free or coupled to polytuftsin, were administrated to mice and the antisera were assayed by ELISA . Coupling the peptides to the polypeptide significantly improved the anti-peptide antibody titer in Freund complete adjuvant or in NaCI 0.9%. Cross-reaction between antibodies induced by the peptides and the native protein was also improved. Polytuftsin alone is very poorly immunogenic.     

潘生丁增强氨甲蝶呤的抗肿瘤作用

外源性核苷能抵消抗代谢药对肿瘤细胞的杀伤作用;核苷转运抑制剂潘生丁则能阻断核苷的这种抵消作用,从而增强抗代谢药的细胞毒性。本研究证明,胸苷和次黄嘌呤可明显抵消氨甲蝶呤对L1210细胞的杀伤作用,潘生丁则能有效地阻断核苷的抵消作用;潘生丁和两性霉素B合用可明显增强氨甲蝶呤对小鼠S180肉瘤的抑制作用,但不增强氨甲蝶呤对动物的毒性。提示潘生丁有可能应用于肿瘤联合化疗。     

维生素D的骨外作用

越来越多的研究表明,维生素D除具有经典的调节钙磷平衡和维持骨骼健康的作用外,还具有其他更为广泛的骨外生物学效应,如调节免疫、抗肿瘤、保护中枢神经系统和防治代谢综合征等作用.本文就相关方面的研究进展进行综述.     

Hepatitis B virus genetic diversity and its impact on diagnostic assays

Summary.  Hepatitis B virus (HBV) circulates in blood as closely related, but genetically diverse molecules called quasispecies. During replication, HBV production may approach 10¹¹ molecules/day, although during peak activity this rate may increase 100–1000 times. Generally, DNA polymerases have excellent fidelity in reading DNA templates because they are associated with an exonuclease which removes incorrectly added nucleotides. However, the HBV-DNA polymerase lacks fidelity and proofreading function partly because exonuclease activity is either absent or deficient. Thus, the HBV genome and especially the envelope gene, is mutated with unusually high frequency. These mutations can affect more than one open reading frame because of overlapping genes. The S gene contains an exposed major hydrophilic region (residues 110–155), which encompasses the 'a' determinant that is important for inducing immunity. Nucleotide substitutions in this region are common and result in reduced binding or failure to detect hepatitis B surface antigen (HBsAg) in diagnostic assays. Adaptive immunity also depends on the recognition of HBsAg by specific antibody and variants pose a threat if they interfere with binding to antibody. Finally, genomic hypervariability allows HBV to escape selection pressures imposed by antiviral therapies, vaccines and the host immune system, and is responsible for creating genotypes, subgenotypes and subtypes.     

Acute Cellular Rejection with CD20-Positive Lymphoid Clusters in Kidney Transplant Patients Following Lymphocyte Depletion

Lymphoid clusters (LC) containing CD20-positive B cells in kidney allografts undergoing acute cellular rejection (ACR) have been identified in small studies as a prognostic factor for glucocorticoid resistance and graft loss. Allograft biopsies obtained during the first episode of ACR in 120 recipients were evaluated for LC, immunostained with CD20 antibody, and correlated with conventional histopathologic criteria, response to treatment and outcome. LC were found in 71 (59%) of the 120 biopsies. All contained CD20 positive B cells that accounted for 5-90% of the LC leukocyte content. The incidence of LC was highest in the patients who had no lymphoid depletion or had been treated with Thymoglobulin preconditioning (79% vs. 75%, respectively) compared to 37% in patients pretreated with Campath (p = 0.0001). Banff 1a/1b ACR were more frequent in the LC-positive than the LC-negative group (96% vs. 80%, respectively; p = 0.0051). With a posttransplant follow-up of 953 +/- 430 days, no significant differences were detected between LC-postitive and LC-negative groups in time to ACR, steroid resistance, serum creatinine and graft loss. CD20+LC did not portend glucocorticoid resistance or worse short to medium term outcomes. CD20+LC may represent a heterogenous collection in which there may be a small still to be fully defined unfavorable subgroup.