主动呼吸控制技术(ABC)在肺癌放射治疗中的应用

目的：使用主动呼吸控制技术（aetive brething control,ABC）治疗非小细胞肺癌患者，评价呼吸运动时肺部肿瘤动度的影响及ABC技术的优势和可行性，并评价近期疗效和急性放射反应。方法：选择9例使用ABC技术联合三维造型放疗技术治疗的非小细胞系癌患者进行分析。CT定位扫描时分别采集ABC和自由呼吸（free breath.FB）状态下的图像，评价呼吸运动对肺部肿瘤动度和PTV边界的影响唾弃；并比较两种计划的DVH，放疗剂量为54-60Gy/18-20次。3Gy/次，1次/天，5天/周，定期随访，评价近期疗效及急性放射反应。结果：应用ABC技术后，隔肌的平均位移从FB时的43.5mm（20.0-32.0mm）降低为3.6mm（0.5-72.mm）,胸壁的侧方位移从FB时的3.2mm（2.8-4.0mm）降低为1.2mm（0.5-1.6mm）.PTV边界可以从FB时的1.5mm减少为0.75cm;肺的V20从21.8%降低为15.0%,减少了30.6%.中位随访6个月时,9例患者中有6例CR,3例PR.急性放射副反应都很轻微,仅为I-II.结论：在肺癌的精确放射治疗中,呼吸动度的影响不可忽视.而ABC系统可以有效的降低呼吸运动时治疗的影响,提高放疗的精确性,减少副反应.,但该系统使用较为复杂,延长了治疗的时间,个别患者不能忍受.     

Distribution of calcium-activated neutral protease inhibitor in the central nervous system of the rat.

The ubiquitous existence of calcium-activated neutral protease (CANP, calpain), an enzyme whose activity is regulated by calcium ions and a specific endogenous CANP inhibitor (calpastatin), is well known. Although there has been much investigation concerning the distribution and role of CANP, investigations of the distribution of the CANP inhibitor using immunohistochemical techniques are rare. We made antiserum against a 40K fragment of cDNA corresponding to two C-terminal repeats of rat liver CANP inhibitor expressed in Escherichia coli. Using this antiserum, we examined the distribution of CANP inhibitor in the rat central nervous system by the ABC technique and compared it with the distribution of CANP. Neurons and glias were stained, with the cytosol stained diffusely and the cell membranes stained clearly and strongly. Axons and myelin were stained faintly, but nuclei and vessels were not stained. The distribution of CANP inhibitor was thus found to be similar to that of CANP.     

HMBA诱导MEC—1细胞分化角蛋白染色的变化

用六亚甲基二乙酰胺（ＨＭＢＡ）作为分化诱导剂，对人粘液表皮样癌细胞系ＭＥＣ－１细胞中角蛋白进行染色，结果发现高分子量角蛋白在被诱导细胞中含量明显增高。分光光度仪检测角蛋白含量，诱导组ｘ±ｓ为２１８±５１，对照组为１４９±４７，两组有显著差异（Ｐ＜００１），这可能与细胞分化有关。     

Quantification and pharmacological characterization of dialysate levels of noradrenaline in the striatum of freely-moving rats: release from adrenergic terminals and modulation by α2-autoreceptors

Information concerning striatal levels of noradrenaline (NA) remains inconsistent. Here we have addressed this issue using a sensitive method of HPLC coupled to amperometric detection. The NA reuptake-inhibitor, reboxetine, selectively elevated levels of NA versus dopamine (DA), and NA levels were also selectively elevated by the α₂-adrenoceptor (AR) antagonist, atipamezole. The actions of atipamezole were mimicked by the preferential α_2A-AR antagonist, BRL44408, while JO-1 and prazosin, preferential antagonists at α_2C-ARs, caused less marked elevations in NA levels. In contrast to antagonists, the α₂-AR agonist, S18616, decreased NA levels and likewise suppressed those of DA. Unilateral lesions of the substantia nigra with 6-hydroxydopamine depleted DA levels without affecting those of NA. Further, the D₃/D₂ receptor agonist, quinelorane, decreased levels of DA without modifying those of NA. However, the D₃/D₂ receptor antagonists, haloperidol and raclopride, and the DA reuptake-inhibitor, GBR12935, elevated levels of both DA and NA. Levels of 5-HT (but not of NA or DA) were increased only by the 5-HT reuptake-inhibitor, citalopram. They were decreased by S18616 and prazosin, reflecting the inhibitory and excitatory influence of α₂- and α₁-ARs, respectively, upon serotonergic pathways. In conclusion, NA in the striatum is derived from adrenergic terminals. Its release is subject to tonic, inhibitory control by α₂-ARs, possibly involving both α_2A- and α_2C-AR subtypes, though their respective contribution requires clarification. A role of dopaminergic terminals in the reuptake of NA likely explains the elevation in its levels elicited by DA reuptake-inhibitors and D₃/D₂ receptor antagonists.     

c-myc反义寡核苷酸对肿瘤细胞表面抗原和对CD3AK杀伤敏感性的调节作用

目的：观察c-myc反义寡核苷酸上调人高转移性肺巨细胞腺癌PG细胞表面抗原分子的表达水平，提高免疫效应细胞杀伤敏感性的作用和机制。方法：PT－PCR方法检测c-myc mRNA表达水平的变化。MTT法检测细胞增殖活性和CD3AK杀伤活性的变化。流式细胞术检测细胞表面抗原表达的变化以及c-myc蛋白表达水平的变化。结果：c-myc反义寡核苷酸（1μmol/L）明显地抑制PG细胞c-myc mRNA和蛋白表达水平，显著提高细胞表面HLA－ABC、ICAM－1分子的表达，其表达率分别从68．44％、38．40％增高到83．16％和42．09％（P＜0．01）。CD3AK对反义寡核苷酸处理的PG细胞的不同效靶比杀伤活性，分别从40．0％、65．0％、74．0％增高到52．0％、74．0％、91．0％（P＜0．01）。结论：c-myc反义寡核苷酸通过抑制PG细胞c-myc mRNA和蛋白表达，上调PG细胞表面HLA－ABC、ICAM－1分子的表达水平，提高其对免疫效应细胞的杀伤敏感性。     

ABC proteins: key molecules for lipid homeostasis

Forty-nine ABC protein genes exist on human chromosomes. Eukaryotic ABC proteins were originally recognized as drug efflux pumps involved in the multidrug resistance of cancer cells. However, it is now realized that one of their major physiological roles is cellular lipid transport and homeostasis, and their dysfunction is often associated with human diseases. ABCA1 and ABCA7 mediate the apolipoprotein-dependent formation of a high-density lipoprotein–cholesterol complex. ABCA3 is indispensable for pulmonary surfactant secretion. ABCG5 and ABCG8 are involved in the secretion of plant sterols and cholesterol into bile. However, the primary substrates and mechanism of action of these ABC proteins have not been precisely defined. In this review article, we first describe the general structure and functions of eukaryotic ABC proteins. The current model of ABCA1 functionality is then explained based on studies on a topological model, subcellular localization, apoA-I dependence of HDL formation, functional defects of Tangier disease mutants, and ATP hydrolysis of purified ABCA1. ABCA1 is supposed to function as a transporter of lipids as well as a receptor for apoA-I. ABCA3 is likely involved in accumulating phospholipids and cholesterol in lamellar bodies and in generating multivesicular structures.     

High expression of MDR1, MRP1, and MRP3 in the hepatic progenitor cell compartment and hepatocytes in severe human liver disease

An increase in bile ductular structures is observed in diverse human liver diseases. These structures harbour the progenitor cell compartment of the liver. Since ATP-binding cassette (ABC) transporters may have a cytoprotective role in liver disease, an immunohistochemical study was performed on human liver specimens from patients with primary biliary cirrhosis (PBC), chronic hepatitis C virus (HCV) infection, submassive cell necrosis, and normal liver. The expression of MDR1, MDR3, BSEP, MRP1, MRP2, and MRP3 was determined using specific antibodies. Dilution series were constructed to determine the critical staining level in order to estimate the factor of up-regulation. In normal liver, hepatocytes showed canalicular staining for MDR3, BSEP, and MRP2. MDR1 stained the canalicular membrane of hepatocytes as well as that of cholangiocytes. MRP3 showed low immunoreactivity of bile duct epithelial cells and centrilobular hepatocytes only. Normal liver showed no immunoreactivity for MRP1. In diseased liver, the expression of MDR3, BSEP, and MRP2 was relatively stable. In PBC, HCV, and submassive necrosis, the expression levels of MDR1, MRP1, and MRP3 were increased. The strongest immunoreactivity was seen after submassive necrosis, where remaining islands of hepatocytes showed strong canalicular staining for MDR1 and MRP3. Regenerating bile ductules at the interface of portal tracts and necrotic areas stained intensely for MDR1, MRP1, and MRP3. In conclusion, MDR1, MRP1, and MRP3 are up-regulated in hepatocytes in severe human liver disease. Strong MDR1, MRP1, and MRP3 reactivity is seen in regenerating human bile ductules.     

The interface between tapasin and MHC class I: identification of amino acid residues in both proteins that influence their interaction

Prior to the binding of antigenic peptide, a complex of chaperone proteins associates with the Major Histocompatibility Complex (MHC) class I heavy chain/β₂m heterodimer. Although each dornain of the MHC class I heavy chain contains amino acid resid uses that influence chaperone binding, there are several pieces of evidence that point to an interaction between the MHC clas 1α2/α3 domains and tapasin. In egard to the site on tapasin involved in the tapasin/MHC interface, we have found that a particular region of tapasin (containing amino acid residues 334–342) is necessary for the binding of tapasin to the MHC class I heavy chain. Our results also indicate that amino acids in this region of tapasin also affect the proportion of MHC class I open forms expressed at the cell surface and MHC class I egress from the endoplasmic reticulurn. Based on these results and those obtained by other laboratories, a model for MHC class I/tapasin interaction is proposed.     

The concentrative nucleoside transporter family,SLC28

The SLC28 family consists of three subtypes of sodium-dependent, concentrative nucleoside transporters, CNT1, CNT2, and CNT3 (SLC28A1, SLC28A2, and SLC28A3, respectively), that transport both naturally occurring nucleosides and synthetic nucleoside analogs used in the treatment of various diseases. These subtypes differ in their substrate specificities: CNT1 is pyrimidine-nucleoside preferring, CNT2 is purine-nucleoside preferring, and CNT3 transports both pyrimidine and purine nucleosides. Recent studies have identified key amino acid residues that are determinants of pyrimidine and purine specificity of CNT1 and CNT2. The tissue distributions of the CNTs vary: CNT1 is localized primarily in epithelia, whereas CNT2 and CNT3 have more generalized distributions. Nucleoside transporters in the SLC28 and SLC29 families play critical roles in nucleoside salvage pathways where they mediate the first step of nucleotide biosynthesis. In addition, these transporters work in concert to terminate adenosine signaling. SLC28 family members are crucial determinants of response to a variety of anticancer and antiviral nucleoside analogs, as they modulate the entry of these analogs into target tissues. Further, this family is involved in the absorption and disposition of many nucleoside analogs. Several CNT single nucleoside polymorphisms (SNPs) have been identified, but have yet to be characterized.     

Molecular cloning and characterization of a novel gene of Candida albicans,CDR1, conferring multiple resistance to drugs and antifungals

By functional complementation of a PDR5 null mutant of Saccharomyces cervisiae, we have cloned and sequenced the multidrug-resistance gene CDR1 of Candida albicans. Transformation by CDR1 of a PDR5-disrupted host hypersensitive to cycloheximide and chloramphenicol resulted in resistance to cycloheximide, chloramphenicol and other drugs, such as the antifungal miconazole, with collateral hypersensitivity to oligomycin, nystatin and 2,4 dinitrophenol. Our results also demonstrate the presence of several PDR5 complementing genes in C. albicans, displaying multidrug-resistance patterns different from PDR5 and CDR1. The nucleotide sequence of CDR1 revealed that, like PDR5, it encodes a putative membrane pump belonging to the ABC (ATP-binding cassette) superfamily. CDR1 encodes a 1501-residue protein of 169.9 kDa whose predicted structural organization is characterized by two homologous halves, each comprising a hydrophobic region with a set of six transmembrane stretches, preceded by a hydrophilic nucleotide binding fold.