槲寄生化学成分的研究 Ⅶ.槲寄生新甙Ⅶ的分离和结构

自中药槲寄生中分离得到一个新的黄酮甙,经波谱测定及水解试验,确定其结构为鼠李秦素-3-O-β-D-芹糖基(1→2)-[6″-(3-羟基-3-甲基戊二酸半酯)]葡萄糖甙,命名为槲寄生新甙Ⅶ(viscumneoside Ⅶ).     

Rapid Rh D genotyping by polymerase chain reaction-based amplification of DNA

Rh (rhesus) D is the dominant antigen of the Rh blood group system. Recent advances in characterization of the nucleotide sequence of the cDNA(s) encoding the Rh D polypeptide allow the determination of the Rh D genotype at the DNA level. This can be of help in cases in which red blood cells are not available for phenotyping, eg, when in concerns a fetus. We have tested three independent DNA typing methods based on the polymerase chain reaction (PCR) for their suitability to determine the Rh D genotype. DNA derived from peripheral blood mononuclear cells from 234 Rh-phenotyped healthy donors (178 Rh D positive and 56 Rh D negative) was used in the PCR. The Rh D genotypes, as determined with a method based on the allele-specific amplification of the 3' noncoding region of the Rh D gene described by Bennett et al (N Engl J Med 329:607, 1993), were not concordant with the serologically established phenotypes in all cases. We have encountered 5 discrepant results, ie, 3 false-positive and 2 false-negative (a father and child). Rh D genotyping with the second method was performed by PCR amplification of exon 7 of the D gene with allele-specific primers. In all donors phenotyped as D positive tested so far (n = 178), the results of molecular genotyping with this method were concordant with the serologic results, whereas a false-positive result was obtained in one of the D-negative donors (also false-positive in the first method). Complete agreement was found between genotypes determined in the third method, based on a 600-bp deletion in intron 4 of the Rh D gene described by Arce et al (Blood 82:651, 1993), and serologically determined phenotypes. The Rh blood group system is complex, and unknown polymorphisms at the DNA level are expected to exist. Therefore, although genotypes determined by the method of Arce et al were in agreement with serotypes, it cannot yet be regarded as the golden standard. More experience with this or other methods is still needed.     

Sulfhydryl reducing agents and shape regulation in human erythrocytes

Metabolic crenation of red cells is reversible; on addition of nutrients, echinocytes recover the normal discoid shape. When the shape recovery takes place in the presence of reducing agents such as dithiothreitol (DTT), morphological change continues until the cells are stomatocytic. The degree of stomatocytosis varies, depending on the cell morphology when the nutrients and reducing agent are added. DTT has minimal effect on the shape of normal discocytes, but in its presence, mildly echinocytic cells become slightly cupped and advanced- stage echinocytes become severely stomatocytic. DTT must be present continuously for development and retention of stomatocytosis; echinocytes preincubated with or metabolically depleted in DTT do not become stomatocytic when supplemented in the absence of DTT, and DTT- induced stomatocytes revert to discocytes when the reducing agent is removed. DTT has no effect on adenosine triphosphate synthesis or equilibrium cell glutathione levels, and the induced stomatocytosis is not inhibited by excluding oxygen from cells during depletion. Spectrin phosphorylation and phosphate turnover are not affected by DTT. The echinocyte-to-discocyte transformation coincides with phosphorylation of membrane inner monolayer lipids (diacylglycerol to phosphatidic acid and phosphatidylinositol to phosphatidylinositol-4,5-bisphosphate). Overphosphorylation of these phospholipids is not responsible for the exaggerated shape recovery seen with reducing agents; phosphorylation of inner monolayer lipids proceeds identically in the presence and absence of DTT.     

Association of cell cycle expression of Ia-like antigenic determinations on normal human multipotential (CFU-GEMM) and erythroid (BFU-E) progenitor cells with regulation in vitro by acidic isoferritins

An association has been established between human Ia-like antigenic determinants, expression during DNA synthesis on multipotential (CFU- GEMM) and erythroid (BFU-E) progenitor cells, and the regulatory action of acidic isoferritins in vitro. Treatment of human bone marrow cells with monoclonal anti-Ia (NE1-011) plus complement inhibited colony formation of CFU-GEMM) and BFU-E by 50%-70%. Reduction of colonies was similar whether bone marrow cells were exposed to anti-Ia plus complement, high specific tritiated thymidine (3HTdr), or acidic isoferritins. No further decrease was apparent with 3HTdr or acidic isoferritins after Ia-antigen+ CFU-GEMM or BFU-E were removed, or with anti-Ia plus complement or acidic isoferritins after S-phase CFU-GEMM or BFU-E were removed. Anti-Ia, in the absence of complement, had no effect on colony formation but blocked the inhibition of CFU-GEMM and BFU-E by acidic isoferritins. Demonstration of Ia-antigens on BFU-E and inhibition of BFU-E by acidic isoferritins appeared to require the presence of phytohemmagglutinin leukocyte conditioned medium (PHA-LCM) in the culture medium during the 14-day incubation period. these results implicate Ia-antigen+ cells, acidic isoferritins, and PHA-LCM in the regulation of multipotential and erythroid progenitor cells in vitro.     

Concurrent classical Hodgkin lymphoma and plasmablastic lymphoma in a patient with chronic lymphocytic leukemia/small lymphocytic lymphoma treated with fludarabine: a dimorphic presentation of iatrogenic immunodeficiency-associated lymphoproliferative disorder with evidence suggestive of multiclonal transformability of B cells by Epstein-Barr virus

A small fraction of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma develop Epstein-Barr virus–positive B-cell lymphoproliferative disorders. These Epstein-Barr virus–B-cell lymphoproliferative disorders are thought to be related to immune suppression induced by fludarabine/other chemotherapeutic regimens. As in other immunodeficiency-associated lymphoproliferative disorders, these disorders demonstrate a heterogeneous histological spectrum that ranges from polymorphic to monomorphic to classical Hodgkin lymphoma–like lesions. We report a case of concurrent classical Hodgkin lymphoma and plasmablastic lymphoma in a patient with chronic lymphocytic leukemia/small lymphocytic lymphoma treated with fludarabine. Both classical Hodgkin lymphoma and plasmablastic lymphoma were positive for Epstein-Barr virus-encoded RNA, whereas classical Hodgkin lymphoma was also positive for Epstein-Barr virus- latent membrane protein 1, suggesting a different viral latency. Immunoglobulin gene rearrangement studies demonstrated distinct clones in the plasmablastic lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma. These findings suggest biclonal secondary lymphomas associated with iatrogenic immunodeficiency. Epstein-Barr virus–B-cell lymphoproliferative disorders in the setting of chronic lymphocytic leukemia/small lymphocytic lymphoma, in particular those arising after chemotherapy, should be separated from true Richter's transformation, and be categorized as (iatrogenic) immunodeficiency-associated lymphoproliferative disorder.     

The 20-Minute Rapid MART-1 Immunostain for Malignant Melanoma Frozen Sections

BACKGROUND Immunohistochemical staining has been used to help detect malignant melanoma on Mohs surgery frozen sections. Previous investigators have developed protocols for reliable MART-1 immunostaining of frozen sections, but these protocols are time-consuming.
OBJECTIVE The objective was to report a rapid 20-minute MART-1 immunostaining protocol for frozen sections.
METHODS The protocol was utilized on 30 melanomas treated with Mohs micrographic surgery.
RESULTS The stain clearly highlighted normal background melanocytes, as well as melanocytic hyperplasia and malignant melanoma.
CONCLUSIONS The 20-minute protocol provides a rapid and reliable method for immunostaining of malignant melanoma. The availability of more rapid immunostaining methods improves efficiency of the Mohs laboratory and significantly reduces patient and physician waiting time.     

Clinical review: Post-extubation laryngeal edema and extubation failure in critically ill adult patients

Laryngeal edema is a frequent complication of intubation. It often presents shortly after extubation as post-extubation stridor and results from damage to the mucosa of the larynx. Mucosal damage is caused by pressure and ischemia resulting in an inflammatory response. Laryngeal edema may compromise the airway necessitating reintubation. Several studies show that a positive cuff leak test combined with the presence of risk factors can identify patients with increased risk for laryngeal edema. Meta-analyses show that pre-emptive administration of a multiple-dose regimen of glucocorticosteroids can reduce the incidence of laryngeal edema and subsequent reintubation. If post-extubation edema occurs this may necessitate medical intervention. Parenteral administration of corticosteroids, epinephrine nebulization and inhalation of a helium/oxygen mixture are potentially effective, although this has not been confirmed by randomized controlled trials. The use of non-invasive positive pressure ventilation is not indicated since this will delay reintubation. Reintubation should be considered early after onset of laryngeal edema to adequately secure an airway. Reintubation leads to increased cost, morbidity and mortality.     

可溶性抗HAV抗体Fab片段的原核表达

0　引言　甲型肝炎病毒 (HAV)是危害人类健康的致病原之一 ,目前已有多种用于接触前预防的甲肝疫苗 ;但对于接触后预防或短期到 HAV高流行区的旅游者的预防 ,则多采用免疫球蛋白作被动免疫 .在接触后 (14d内 )和潜伏期早期 ,注射免疫球蛋白预防甲肝的有效率达 85 %左右 .血源性免疫球蛋白虽然效价高 ,应用效果好 ,但可能被血源病原体污染 .因此基因工程人源抗体有望成为接触后预防的首选制剂 .我们从人源噬菌体抗体组合文库中筛选到一株甲肝特异性抗体 [1 ] ,在此基础上构建了可溶性表达载体 ,并获得可溶性表达 ,为该抗体的进一步研究打…