Evaluation of cerebral perfusion from bypass arteries using selective intraarterial microsphere tracer after vascular reconstructive surgery.

BACKGROUND AND PURPOSETo detect areas of cerebral perfusion from bypass arteries after vascular reconstruction, we administered selective intraarterial microsphere tracer into the external carotid arteries and determined (via single-photon emission computed tomography [IA-SPECT]) whether the distribution of radiotracer matched the arteriographic distribution of contrast material as shown on external carotid angiograms.METHODSWe compared the extent of regional distribution of tracer after external carotid artery injection of 20 to 40 MBq of 99mTc-HMPAO or 99mTc-ECD with that of contrast medium on the external carotid angiograms in 582 cortical regions in 12 patients with atherosclerotic occlusive disease and in 18 patients with moyamoya disease.RESULTSMarked accumulation of tracer was found only in the expected, specific, newly developed areas of cerebral perfusion from bypass arteries. The regional distribution of tracer corresponded to that of contrast medium in 523 regions (90%) and did not correspond in 59 regions (10%). Significant overestimation of the distribution of contrast material relative to that of tracer was observed in the patients with moyamoya disease.CONCLUSIONSPECT showed slightly different distribution of tracer from that predicted by conventional angiography. IA-SPECT should enhance the analysis of newly developed areas of cerebral perfusion from the bypass arteries.     

胞嘧啶脱氨酶的原核表达和多克隆抗体的制备

目的：在原核系统中表达并纯化大肠杆菌胞嘧啶脱氨酶（cytosine deaminase,CD)，制备鼠抗大肠杆菌CD多克隆抗体，方法：亚克隆CD基因到原核表达载体pMAL-c2和pBV222中，并转化入大肠杆菌DH5α内，诱导表达并纯化MBP-CD和6his-CD融合蛋白，用纯化的MBP-CD融合蛋白免疫小鼠制备多克隆抗体。结果：通过重组质粒的酶切筛选出重组阳性克隆，成功地表达和纯化出MBP-CD和6his-CD融合蛋白，用纯化的MBP-CD成功制备了鼠抗CD多克隆抗体，并用6his-CD和GST-CD重组蛋白进行Western印迹分析，证实了抗体的正确性，结论：应用多克隆抗体可以检测体内外CD基因的表达，为临床前和临床上深入开展CD基因的生物治疗研究提供重要的实验材料。     

Antigen presentation by a B-cell line transfected with cloned immunoglobulin heavy- and light-chain genes specific for a defined hapten.

The rearranged genes encoding immunoglobulin heavy (mu) and light (kappa) chains specific for the hapten 2,4,6-trinitrophenyl (Tnp) were introduced into a B-lymphoma line that bears surface IgG with an unknown specificity and expresses surface Ia molecules. A transformant expressing surface IgM specific for Tnp was obtained. The transformant was found to present Tnp-proteins to antigen (protein)-specific T cells far more efficiently than the parenteral B-lymphoma line. This artificial system, utilizing recombinant DNA technology and gene transfer, provides several approaches for the study of T-cell-B-cell interactions.     

Relationship between in vivo first-order intestinal absorption rate constant and the membrane permeability clearance

An attempt was made to explore the quantitative relationship between the intestinal absorption data obtained from in vivo studies and in situ perfusion studies. The time course of the fraction remaining to be absorbed of L-glucose, erythritol, and urea in the small intestine following the intrajejunal administration to rats was described by a one-compartment model. Thus derived first-order intestinal absorption rate constants (ka) obtained from the in vivo studies in rats were compared with the membrane permeability clearances (CLa,m) estimated in a single-pass perfusion system. Not only were ka and CLa,m in the same increasing order of L-glucose less than erythritol less than urea, but also the operational luminal volumes given as CLa,m/ka were in agreement with the in vivo luminal volume of jejunum estimated by an inulin dilution method. This result suggests that the in vivo intestinal absorption rate (or ka) can be correlated with the intestinal membrane permeability (or CLa,m) by taking the in vivo luminal volume into account.