应用四唑盐比色法对5种骨水泥的细胞毒性的测试

0　引言　应用细胞培养法对牙科材料的生物相容性进行评价是一种简便、有效、经济的方法 .近年来 ,国内外有许多学者报道用 MTT检测细胞活性 ,并认为用 MTT法可以代替活细胞计数、同位素标记进行细胞毒性试验 .我们应用 MTT法对 5种骨水泥的细胞毒性进行了评价 ,并对有关问题进行了讨论 .1　材料和方法1.1　测试材料　 1号 :生物水泥 ,2号 :羟基磷灰石人工骨 ,3号 :氰基丙烯酸酯骨水泥 1号 (自制 ) ,4号 :氰基丙烯酸酯骨水泥 2号 (自制 ) ,5号 :氰基丙烯酸酯骨水泥 3号 (自制 ) .阴性对照采用珊瑚 ,阳性对照采用聚氯乙烯 .1.2　实验步骤…     

三尖杉碱吲哚类似物的全合成

目的合成三尖杉碱吲哚类似物。方法以色胺为原料经缩合、环合、水解与脱羧反应得吲哚哌啶酮化合物,经Bischler-Napieralski反应得烯胺。通过烯胺的溴化与氧化-重排反应得到吲哚氮杂     

Nasotracheal enterococcal carriage and resistomes: detection of optrA-, poxtA- and cfrD-carrying strains in migratory birds,livestock, pets,and in-contact humans in Spain

European Journal of Clinical Microbiology & Infectious Diseases - This study determined the carriage rates and antimicrobial resistance (AMR) genes of enterococci from...     

Soft-Tissue Tumors: Diagnosis, Evaluation, and Management

Benign soft-tissue neoplasms and tumorlike conditions of the musculoskeletal system are common. Sarcomas are less frequent, with only 5,000 new cases diagnosed each year in the United States. After plain radiographs of the affected area have been obtained, magnetic resonance (MR) imaging (both T1- and T2-weighted sequences) is the best imaging modality for detecting and characterizing the lesion. Although MR imaging is not specific in determining whether lesions are benign or malignant, it can be useful in evaluating other characteristics, such as size, pattern of growth, integrity of natural boundaries, and homogeneity. Biopsy must be done carefully, so as not to adversely affect the outcome. Technical considerations include proper location and orientation of the biopsy incision, meticulous hemostasis, and frozen-section analysis to ensure that diagnostic material has been obtained. Effective treatment requires close coordination between the surgeon, the radiation oncologist, the pathologist, the plastic surgeon, and the diagnostic radiologist. Limb-salvage surgery has resulted in a local control rate greater than 90%. High-grade tumors that are larger than 5 cm in diameter have the worst prognosis. The role of chemotherapy remains controversial and unresolved.     

Rivastigmine: a review

The acetylcholinesterase inhibitors are the first useful and useable drugs for palliative treatment of dementia of the Alzheimer type. This article reviews the second-generation carbamate cholinesterase inhibitor, rivastigmine (EXELON, Novartis, Basel) whose distinctive pharmacology is not only of immediate clinical relevance but also the key to some tantalizing therapeutic possibilities.     

A method for genotyping murine arylamine N-acetyltransferase type 2 (NAT2): a gene expressed in preimplantation embryonic stem cells encoding an enzyme acetylating the folate catabolite p-aminobenzoylglutamate.

Mice have three arylamine N-acetyltransferase (NAT) isoenzymes (NAT1, NAT2, and NAT3) of which NAT2 is known to be polymorphic. Humans have two polymorphic isoenzymes, NAT1 and NAT2. The isoenzymes mouse NAT1 and human NAT2 are expressed predominantly in the liver and intestine and are involved in drug and xenobiotic metabolism. Mouse NAT2 and human NAT1 have a widespread tissue distribution and the folate catabolite p-aminobenzoylglutamate (pAB-Glu) has been proposed as a candidate endogenous substrate. All mice have detectable NAT2 activity, although inbred mouse strains have either a fast or slow acetylator phenotype conferred by the presence of either NAT2*8 (fast) or NAT2*9 (slow) alleles at the NAT2 locus. In this report, we describe a simple method for distinguishing these murine alleles by polymerase chain reaction followed by restriction fragment length polymorphism analysis. We compared the tissue distribution of the acetylation activity found in both fast (C57BL/6J) and slow (A/J) acetylating strains of mice using pAB-Glu and p-aminobenzoic acid as probe substrates. It has previously been demonstrated that murine NAT2 is expressed in the neural tube prior to closure (Stanley L, Copp A, Rolls S, Smelt V, Perry VH and Sim E, Teratology 58: 174-182, 1998). We demonstrate here that murine NAT2 is expressed in preimplantation embryonic stem cells. Murine NAT2 is likely to be expressed prior to neurulation and this may be important in view of the protective role of folate in neural tube development.     

How do normal subjects learn a simple adaptative task: How and why do paranoid schizophrenic patients fail?

Summary The authors studied the behavior of normal subjects and paranoid schizophrenic patients in a simple problem-solving situation. The schizophrenics were divided into two sample groups, one of individuals under treatment and the other of individuals not under treatment.The learning process involved in this problem-solving situation is very similar to an instrumental conditioning, and can be understood by means of the following assumptions: (1) the subjects use decision functions in reacting to the stimuli, although they may be not fully aware of this; (2) learning is the result of successive transformations of these decisions in the course of time; (3) the changes have specific probabilities and are related to (a) those responses which are made to the latest stimuli, and (b) a differential probability for decision functions which were effective, or only interrupted painful reinforcement, or were completely ineffective.In schizophrenics further factors of importance were (1) an inertia factor and (2) the rigidly continued use of unsuccessful or only partially successful decision criteria.The authors used a systems theory based on Galois field theory and a calculus of operators specifying three groups of subjects. A computer program based on these hypotheses was tested in a simulation experiment.The statistical evaluation of the results showed a congruence between the theoretical approach and the experimental data.This work was carried out with financial support from the Institute de Alta Cultura, Lisbon, between 1970 and 1974     

Inhibition of butyrylcholinesterase activity by some isoquinoline alkaloids

The inhibition of butyrylcholinesterase activity in human serum by protoberberine, benzophenanthridine and aporphine alkaloids as well as four model compounds has been studied. The mechanism of the inhibition is discussed on the basis of the different types of interaction of these compounds with butyrylcholinesterase and acetylcholinesterase.