ULTRASTRUCTURAL INVESTIGATION OF EXPERIMENTAL FRACTURE HEALING ROLE OF OSTEOGENESIS PLAYED BY FIBROBLASTS

Transmission electron microscopic investigation of standardized fractures of radii in 50 rabbits re vealed that fibroblasts took part in the formation of bony callus. The osteogenetic role played by the fibroblasts can be categorized into the following 5 aspects: a. Fibroblasts synthesize and secrete Type collagen fibrils and induce deposition of calcium salt crystals in the collagen fibrils. b. Fibroblasts produce matrix vesicles in their surroundings. These matrix vesicles become calcified and turn into floccu- lent calcospherules which coalesce and fuse into bone tissues. c. Fibroblasts harbor calcium granules in their mitochondria, thus providing calcium for calci- fication of the intercellular matrix and bone forma tion between the cells. d. Fibroblasts can transform directly into osteocytes; there is bone formation around the fibroblasts, the bone tissues surround the fibroblast in the form of bony lacuna, then the fibro- blast in the lacuna transforms into osteocyte. e. Fibroblasts can undergo degenerative changes leading to decease and replacement by bone tissues.     

改制先改革,改革先改人宿迁医改的政府内应力

“人民,是创造历史的真正动力”——壮哉斯言；“真理,只掌握在少数人手中”——诚哉斯言。尽管发生在苏北宿迁的这场席卷城乡的改革,绝不可能只由少数精英分子独立完成,但最初的推动力,是全民意志的厚积薄发?是少数精英的灵光一闪?抑或是一场上级授权、政府定规、全民参与的社会实验?     

Schedule-induced cocaine drinking: choice between cocaine and vehicle

Rats were exposed to daily 3-hr schedule-induced polydipsia sessions (fixed-time 1-min food-pellet delivery) with two drinking fluids available: cocaine solution and water. Fluid position was alternated daily. Polydipsia occurred mostly from a preferred-side spout (position preference) until cocaine solution concentration was increased to between 0.52 and 1.04 mg/ml and animals drank mostly water. Within a lower concentration range (0.28-0.6 mg/ml) maximum session cocaine intakes ranged from 54.3 to 120.1 mg/kg. Postsession serum cocaine levels were about 200 ng/ml. At individually chosen cocaine solution concentrations, the addition of saccharin to the solution did not increase cocaine intake, but a compound solution (saccharin plus glucose) did. With progressive dilution of the compound vehicle, an almost complete preference for cocaine solution was maintained. But with a return to water as the vehicle, animals reverted to a position preference after a few sessions, although one maintained a clear cocaine preference. Schedule-induced polydipsia produced chronic, oral self-administration of cocaine resulting in pharmacologically significant intakes and serum levels.     

异落新妇甙的结构研究

从百合科菝葵属植物土茯苓(Smilaxg labra Roxb.)根茎的乙醇提取物中分得一个新的天然化合物(I),命名为异落新妇甙(isoastilbin)。根据元素分析,UV,IR,¹H-NMR,¹³C-NMR,2DNMR及FAB-MS,确定化合物I的结构为5,7,3',5'-四羟基二氢黄酮醇-3-O-α-L-鼠李糖甙。     

Quantitative observation by enzyme cytochemistry of human rectal adenocarcinoma cells killed by LAK cells

Activity of succinic dehydrogenase(SDH)and acid phosphatase(AcPase)of effector-target cells during the process of LAK cells killing HR8348 cells was estimated by enzyme cyto-chemistry technique.SHD positive granules and AePase gray level were assayed with MIAS-300image analyser.The results showed:(1)After cocultivation of effector and target cells for vari-ous times,the activity of AcPase of HR8348 cells was apparently higher than that of the controlgroup,and it increased following prolonged coincubation.SDH activity of target cells increasedmarkedly within 30 and 60 rain cocultivation,but became low after 90 min treatment.(2)Ac-Pase content within LAK cells at 60,90,120,180 and 240 rain cocultivation was significantlyhigher than that of control group(P<0.01).The phenomenon of high AcPase and SDH activitywithin effector-target cells indicates that the function of the two types of cells was in an activestate.At the early stage of effector-target combining,the increase of SDH with HR8348 cellsmay be related to defensive function of the target cells.Higher AcPase activity of target cells in-dicates the activation of lysosomal enzyme which serves as the material basis for autolysis of thecells.     

Detection of Bacteroides fragilis Enterotoxin Gene by PCR

Bacteroides fragilis constitutes about 1% of the bacterial flora in intestines of normal humans. Enterotoxigenic strains of B. fragilis have been associated with diarrheal diseases in humans and animals. The enterotoxin produced by these isolates induces fluid changes in ligated intestinal loops and an in vitro cytotoxic response in HT-29 cells. We developed a nested PCR to detect the enterotoxin gene of B. fragilis in stool specimens. After DNA extraction, a 367-bp fragment was amplified with two outer primers. The amplicon from this reaction was subjected to a second round of amplification with a set of internal primers. With these inner primers, a 290-bp DNA fragment was obtained which was confirmed as part of the B. fragilis enterotoxin gene by Southern blotting with a nonradioactive internal probe and a chemiluminescence system. By this approach, B. fragilis enterotoxin gene sequences were detected in eight known enterotoxigenic human isolates and nine enterotoxigenic horse isolates. No amplification products were obtained from DNA extracted from 28 nonenterotoxigenic B. fragilis isolates or B. distasonis, B. thetaiotaomicron, B. uniformis, B. ovatus, Escherichia coli, or Clostridium difficile. The sensitivity of this assay allowed us to detect as little as 1 pg of enterotoxin DNA sequences or 100 to 1,000 cells of enterotoxigenic B. fragilis/g of stool. Enterotoxin production of all isolates was confirmed in vitro in HT-29 cells. A 100% correlation was obtained between enterotoxin detection by cytotoxin assay and the nested PCR assay. This rapid and sensitive assay can be used to identify enterotoxigenic B. fragilis and may be used clinically to determine the role of B. fragilis in diarrheal diseases.     

谷氨酸诱导体外培养的鸡胚脊髓神经细胞释放NO

用鸡胚脊髓神经细胞的原代培养,测定细胞中亚硝酸盐的含量,研究了谷氨酸(Glu)对原代培养神经细胞中NO的影响。结果表明,谷氨酸作用于原代培养的鸡胚脊髓神经细胞,在诱导神经细胞释放乳酸脱氢酶(LDH)的同时,还可诱导细胞释放一氧化氮(NO)。如先用NO合成酶抑制剂L-NOARG作用细胞,再加入Glu,则发现L-NOARG能降低Glu导致的培养液中LDH活性升高。提示NO可能参与介导Glu的神经毒性作用。     

对一宗入境二级放射货包的监测结果分析

汕头卫生检疫局空港处对汕头航空口岸—宗入境二级货包的监测过程及对有关运输工作人员作了放射知识问卷调查。从中发现。运输单位货物存放设施落后。有关工作人员放射卫生知识欠缺，对放射污染可能造成的危害缺乏正确的认识。为此，笔者提出了自己的看法，以期对放射监测工作的进一步完善提供参考。     

纤维支气管镜胸膜腔检查对原因不明胸腔积液的诊断价值

为评价纤维支所管镜行胸膜检查在诊断原因不明胸腔积液中的价值，用纤维支气管镜对１０例原因不明的胸腔积液患者进行胸腔检查。结果９例２检查后明确了病因，且无并发症，提示该法对于不明胸腔积液的诊断是一种阳性率高、安全、简便的检查方法。     

锗元素与抗肿瘤药物(Ⅱ)(续上期)

综述了有机锗抗肿瘤药物，对β－羧乙基锗倍半氧化物（Ｇｅ－１３２）和螺锗在肿瘤学中的作用以及抗癌效应机制作出评价。自８０年代起至今，又有含硫杂、柠檬酸、氨基酸、苯基的锗化合物，以及锗酵母、含锗中草药等被先后合成出来。在几类具有生物活性的有机锗化合物中，仍首推Ｇｅ－１３２，螺锗及其衍生物为低毒有效抗肿瘤候选药物，然而对于锗导致的毒性及其机理仍需进一步加以探讨。