Cloning, functional activities and in vivo tissue distribution of rat NKR-P1+ TCR alpha beta + cells

We have successfully cloned nine NKR-P1+ TCR alpha beta + cells from PVG rat spleens, utilizing murine macrophage inflammatory protein-1 alpha (MIP-1 alpha) and IL-2. These clones are either double negative (DN, CD4-CD8-), which included clones 3.31, 3.71, 4.19, 4.59 and 4.65, or single positive (SP, CD4+CD8-), which included clones 1.64, 3.8, 3.76 and 3.78. No CD8+ clone was recovered. All nine clones are restricted in terms of their expression of the V beta antigens, since they express V beta 8.2 but not V beta 8.5, V beta 10 or V beta 16. These clones are agranular and they fall to generate NK or LAK activity upon incubation with IL-2, IL-12 or their combination. On the basis of their production of intracellular cytokines they can be divided into three categories: (I) SP clones (1.64, 3.8, 3.76 and 3.78) do not produce IL-2 or IL-4, but produce IFN-gamma and IL-12, and they vary in their production of IL-1, RANTES or tumor necrosis factor (TNF)-alpha; (II) DN clones 4.59 and 4.65 produce IL-1 alpha and IFN-gamma only, and fall to produce other cytokines; and (III) DN clones 3.31, 3.71 and 4.19 produce IL-1 alpha, IL-1 beta, IL-2, IL-12, IFN-gamma, RANTES and TNF-alpha. From all the clones examined only DN clones 3.31 and to a lesser degree 4.19 produce IL-4. In vivo tissue localization of clones 3.8, 3.31 and 4.59 shows that these cells distribute into the liver and bone marrow 24 h post i.v. administration. Their accumulation in the liver and bone marrow along with their ability to secrete various cytokines suggest that these cells may influence the generation, differentiation or apoptosis of immune or hematopoietic cells.      

(-),(+)黄皮酰胺对鼠脑内 NMDA- 受体的影响

用[³H]MK-801放射配体竟争结合法测定了(-),(+)黄皮酰胺对大鼠前脑,海马,皮层等部位突触膜的NMDA-R的作用,以探讨其促智机制。同时用饱和实验分析po给药10d后,小鼠脑内该受体密度的变化。结果表明:(-),(+)黄皮酰胺对脑内各部位的NMDA受体均无特异亲和力。但(-)黄皮酰胺在体给药10d后能使小鼠脑内NMDA受体密度显著增高,并呈一定的量效关系。提示黄皮酰胺的药理作用有光学选择性;(-)黄皮酰胺增加脑内NMDA受体密度为其促智作用提供了重要理论依据。     

Epstein–Barr virus in the pathogenesis of oral cancers

Epstein–Barr virus (EBV) is a ubiquitous gamma‐herpesvirus that establishes a lifelong persistent infection in the oral cavity and is intermittently shed in the saliva. EBV exhibits a biphasic life cycle, supported by its dual tropism for B lymphocytes and epithelial cells, which allows the virus to be transmitted within oral lymphoid tissues. While infection is often benign, EBV is associated with a number of lymphomas and carcinomas that arise in the oral cavity and at other anatomical sites. Incomplete association of EBV in cancer has questioned if EBV is merely a passenger or a driver of the tumorigenic process. However, the ability of EBV to immortalize B cells and its prevalence in a subset of cancers has implicated EBV as a carcinogenic cofactor in cellular contexts where the viral life cycle is altered. In many cases, EBV likely acts as an agent of tumor progression rather than tumor initiation, conferring malignant phenotypes observed in EBV‐positive cancers. Given that the oral cavity serves as the main site of EBV residence and transmission, here we review the prevalence of EBV in oral malignancies and the mechanisms by which EBV acts as an agent of tumor progression.     

Protein phosphorylation in neutrophils from patients with p67-phox- deficient chronic granulomatous disease

Neutrophils are known to contain a major 67-kD protein that undergoes enhanced phosphorylation and translocation to the membrane during cell stimulation. Recent studies have assumed that this 67-kD phosphoprotein is the 67-kD subunit of the phagocyte oxidase (p67-phox). We compare here the protein phosphorylation patterns in lysates of normal neutrophils and neutrophils from patients with chronic granulomatous disease (CGD) that are completely deficient in p67-phox. The phosphoproteins were labeled by incubation of the cells with radioactive inorganic phosphate (32Pi) or by the addition of [gamma- 32P]ATP to electropermeabilized neutrophils. With either method, stimulation of the normal or CGD cells always resulted in an enhanced incorporation of 32p into two proteins in the 67-kD area. The extent of phosphorylation of these two proteins was very similar in the normal and CGD cells when permeabilized neutrophils loaded with [gamma - 32P]ATP were compared. Moreover, no overall differences in the protein phosphorylation patterns were observed between the normal and CGD cells. Our data indicate that the major 67-kD phosphoproteins observed in stimulated neutrophils are clearly different from p67-phox.     

Spectrin-alpha I/61: a new structural variant of alpha-spectrin in a double-heterozygous form of hereditary pyropoikilocytosis

Recent biochemical studies have led to the identification of abnormal spectrins in the erythrocytes of patients with hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis (HE). In this report we describe the biochemical characterization of the erythrocytes from a proband with severe HPP who is doubly heterozygous for two mutant spectrins (Sp): Sp alpha I/74 and a new, previously undetected, mutant of alpha-spectrin designated Sp alpha I/61. The proband's erythrocytes are unstable when exposed to 45 degrees C, and her membrane skeletons exhibit instability to shear stress. The content of spectrin in the proband's erythrocyte membranes is decreased to 75% of control values. The amount of spectrin dimers in crude 4 degrees C spectrin extracts is increased (58%) as compared with control values (6% +/- 4%). Limited tryptic digestion reveals a marked decrease in the normal 80,000-dalton alpha I domain, an increase in the 74,000-dalton fragment that is characteristic of Sp alpha I/74, and an increase in a series of new fragments of 61,000, 55,000, 21,000, and 16,000 daltons. Both parents are asymptomatic, but they have increased amounts of spectrin dimers (17% to 25%). Limited tryptic digestion of the father's spectrin demonstrates the presence of a previously identified abnormal spectrin (Sp alpha I/74) that is characterized by a decrease in content of the 80,000-dalton peptide and an increase in concentration of the 74,000-dalton peptide. The mother's spectrin digests show a decrease in the amount of 80,000-dalton peptide and the formation of new peptides of 61,000, 55,000, 21,000, and 16,000 daltons. The data indicate that this severe form of HPP is due to the inheritance of two distinct abnormal spectrins, Sp alpha I/74 and a new spectrin mutant, Sp alpha I/61.     

Specificity of autoantibodies in autoimmune thrombocytopenia

In 42 patients with autoimmune thrombocytopenia (AITP) and a positive direct platelet suspension immunofluorescence test (PSIFT), the antigenic specificity of the autoantibodies was studied. Because the autoantibodies were often not detectable in the serum and additional HLA antibodies may disturb the reaction pattern with the platelet panel, we used eluates prepared from the patients' platelets for this study. Thirty-five patients had antibodies equally reactive with normal platelets, irrespective of their antigenic make-up, but not with the platelets from two Glanzmann's disease patients. Absorption and elution experiments in two patients showed that his was probably not due to the presence of a combination of anti-Zwa and anti-Zwb antibodies. Thus, the majority of autoantibodies against platelets seems to be directed against antigenic determinants not present on Glanzmann's disease platelets, but perhaps located on the platelet-membrane glycoproteins IIb and/or IIIa. In ten patients, antibodies of no, or still unknown, specificity were detected. Three of these had additional antibodies not reactive with the platelets of the two Glanzmann patients.     

A human antibody binds to alpha-galactose receptors and mimics the effects of Clostridium difficile toxin A in rat colon

BACKGROUND & AIMS: Nearly all human sera contain an immunoglobulin G antibody (antigalactose) that binds the trisaccharide Gal alpha 1-3Gal beta 1-4GlcNAc expressed on cells from most mammals but not humans. Because the Clostridium difficile toxin A receptor in rodents contains this trisaccharide, the aim of this study was to examine whether antigalactose could mimic the enterotoxic effects of toxin A and bind to receptors containing this trisaccharide. METHODS: Fluid secretion, [3H]-mannitol permeability, and release of rat mast cell protease II and prostaglandin E2 were measured after luminal exposure of rat colon to either purified human anti-galactose, control immunoglobulin G, toxin A, or buffer. RESULTS: Toxin A (5 micrograms) and antigalactose (250 micrograms) but not control immunoglobulin (250 micrograms) stimulated colonic fluid secretion and caused increased mannitol permeability and rat mast cell protease II release. Antigalactose and toxin A and, to a lesser degree, control immunoglobulin G also stimulated release of prostaglandin E2, but only toxin A produced acute inflammation of rat colonic mucosa. Antigalactose and toxin A bound specifically to a single class of colonic brush border receptors with dissociation constants of 10(-6) mol/L and 5.4 x 10(-8) mol/L, respectively. CONCLUSIONS: Fluid secretion, increased permeability, and mast cell activation occur in rat colon when toxin A or human antigalactose immunoglobulin G bind to receptors bearing the trisaccharide Gal alpha 1-3Gal beta 1-4GlcNAc. (Gastroenterology 1996 Jun;110(6):1704-12)     

Comparison of flow-mediated dilatation of the brachial artery in coronary patients with low-density lipoprotein cholesterol levels <80 mg/dl versus patients with levels 80 to 100 mg/dl

Testing of peripheral vascular endothelial function was performed in subjects who had coronary artery disease and a low-density lipoprotein (LDL) cholesterol level <100 mg/dl. LDL cholesterol was an independent predictor of flow-mediated dilation of the brachial artery (p = 0.010). The 63 subjects who had an LDL cholesterol level <80 mg/dl had better endothelial function (flow-mediated dilation 8.4 +/- 3.8%) than did 47 subjects whose level of LDL cholesterol was 80 to 100 mg/dl (flow-mediated dilation 6.8 +/- 4.0%, p = 0.03). The beneficial effects of LDL cholesterol levels <80 mg/dl on endothelial function were more apparent in subjects who had low levels of high-density lipoprotein cholesterol than in those who had normal levels. These data support recent reports that decreasing levels of LDL cholesterol below those currently recommended provides additional benefits and suggest that this benefit may be due in part to increased endothelial function.     

Duodenal hematoma: the ring sign in MR imaging

Proper management of duodenal hematoma requires that an accurate diagnosis be made using noninvasive radiological methods. Conventional imaging may be nonspecific if there is no history of trauma or coagulopathy. Two cases of duodenal hematoma that were imaged by magnetic resonance (MR) and computed tomography (CT) are described. In both cases the hematoma had a well-defined concentric ring configuration on MR images, a finding which helped establish the diagnosis. MR imaging may provide tissue-specific characterization of duodenal hematomas.