Increased spontaneous secretion of rheumatoid factor by intestinal lamina propria mononuclear cells from Crohn's disease but not ulcerative colitis patients.

Increased levels of rheumatoid factors (RF) have been observed in the serum of Crohn's disease but not ulcerative colitis patients, and have been proposed to relate to an increased state of intestinal lymphocyte activation. We have therefore examined the spontaneous in vitro secretion of RF by intestinal lamina propria mononuclear cells (MNC) isolated from specimens from control and inflammatory bowel disease (Crohn's disease, ulcerative colitis) patients. Normal intestinal lamina propria MNC spontaneously secrete rheumatoid factors of different isotypes during 14 days of in vitro culture (9.7 ng/ml IgA RF, 11.6 ng/ml IgM RF and 64.6 ng/ml IgA anti-Fc (IgG)). In matched studies intestinal MNC isolated from normal large bowel exhibited significantly greater levels of RF synthesis and secretion in vitro than normal small bowel intestinal MNC. A large increase in spontaneous RF secretion was observed from Crohn's disease intestinal MNC (21.4 ng/ml IgA RF, 21.4 ng/ml IgM RF, and 108.15 ng/ml IgA anti-Fc (IgG)), when compared with normal controls. The amount of RF secreted was dependent on the amount of inflammatory activity of the bowel specimens, from which the MNC were isolated (198.3 ng/ml of IgA anti-Fc(IgG) from involved versus 50.0 ng/ml from matched non-involved tissue). Ulcerative colitis MNC released decreased amounts of RF (7.1 ng/ml IgA RF, 6.2 ng/ml IgM RF, and 42.3 ng/ml IgA anti-Fc(IgG)). These observations using isolated intestinal MNC may explain the findings of RF changes in the sera of inflammatory bowel disease patients. Our observations support the hypothesis of a heightened state of activation in normal intestinal lamina propria MNC, which is further increased in active Crohn's disease. The dissimilarities observed between Crohn's disease and ulcerative colitis may indicate fundamental differences in disease pathophysiology and will lead to further studies exploring intestinal immunoregulatory properties of RF.     

Induction of specific anti-actin antibodies and their measurement by ELISA technique.

Using the ELISA technique we have been able to quantify antibodies directed against actin and to follow the kinetics of antibody production. Specific anti-actin antisera have been raised in rabbits by immunization with chemically modified white muscle rabbit actin. Two or three dinitrophenyl groups linked per actin molecule were sufficient to break natural tolerance, while linkage of three phosphorylcholine groups to actin was not.     

采用小波描述子实现表面渲染数据的渐进传输

为了实现医学可视化的网络应用,提出一种基于小波描述子的表面渲染数据渐进传输方法.首先针对用于表面重建的序列平面轮廓为周期序列的特点,提出数字轮廓小波描述子的概念.基于小波描述子进行渐进传输的基本思想是,在发送端将轮廓采用小波描述子表示,然后对这些小波描述子系数序列渐进发送.在接收端,利用陆续收到的描述子系数序列重构轮廓,进行表面重建与渲染,重建精度和渲染效果随着不断收到‘细节'部分数据而得到改善并最终达到发送端的效果.该方法可以在数据无损传输的情况下,降低对传输网络带宽的要求,文中实验研究表明了方法的可行性.     

Melanosis of the appendix: common in the paediatric age group

AIMS: The objective of this study was to assess apoptotic activity in gestational trophoblastic disease (GTD) and its prognostic value in hydatidiform mole (HM). METHODS AND RESULTS: Expression of the specific caspase cleavage site within cytokeratin 18 was assessed immunohistochemically using the monoclonal antibody M30 CytoDeath in 12 spontaneous abortions, 22 partial and 57 complete HM, eight choriocarcinoma (CCA) and 28 normal placentas. The M30 immunoreactivity occurred predominantly in the syncytiotrophoblasts. A significantly higher M30 index in HM and CCA was found when compared with normal placentas and spontaneous abortions (P < 0.001). The M30 index of those HM which spontaneously regressed was significantly higher than those HM which developed persistent disease requiring chemotherapy (P < 0.001). The M30 index correlated with another apoptotic index previously detected by TdT-mediated dUTP nick-end labelling (TUNEL) (P = 0.007) and the proliferation index assessed by the Ki67 antigen (P = 0.034). CONCLUSIONS: We conclude that apoptosis is important in the pathogenesis of GTD. Assessment of apoptotic activity in HM by the M30 index may be considered as an alternative prognostic indicator for predicting the clinical behaviour.     

Egg allergy, influenza vaccine, and immunoglobulin E antibody.

In a study of 70 patients with asthma, rhinitis, and eczema, those giving a definite history of allergic reactions to egg more frequently showed positive skin tests to egg extracts (p = less than 0.003), the wheal diameters of which were significantly larger (p = less than 0.01) than in patients with only a possible or no such history. Patients with a definite history of egg allergy had significantly higher levels of specific IgE antibody against egg yolk, egg white, and allantoic fluid than patients in the other two groups (p = less than 0.005). Seven patients, all of whom had given a definite history of allergy to egg, were found to have positive skin prick tests to influenza vaccine, at the concentration used in medical practice. Two of these patients had previously been given influenza vaccine and both had developed adverse reactions. Of the 22 patients giving a definite history of allergy to egg, the 7 (35 per cent) with positive skin tests to influenza vaccine had significantly larger skin tests and higher levels of specific IgE antibody to the egg extracts than the group as a whole (p = less than 0.001). Allergic reactions to influenza vaccine are likely to occur in patients who have a definite history of allergy to egg and large skin prick test reactions or high levels of specific IgE antibody to egg extracts. Those at risk can best be identified by skin prick testing with egg extracts and undiluted influenza vaccine.     

Demonstration of T4, T8, M1 and B7 determinants on human T cells with a rosette test: implications for the assay specificity of monoclonal antibodies

Under optimal test conditions significantly more freshly isolated human T cells reacted with OKT4, OKT8, OKM1 and OKB7 monoclonal antibodies (Mabs) in the indirect antiglobulin rosetting reaction (IARR) than by indirect immunofluorescence. Rabbit erythrocytes (E) coated with anti-mouse immunoglobulin were more sensitive indicator cells in the IARR than similarly coated sheep E. Treatment of T cells with neuraminidase further enhanced T cell reactivity in the IARR with each Mab so that an average of 60% or more of T cells were T4+, T8+ and M1+ and at least 40% had the T4+ T8+ phenotype. The various findings suggest that the rosette assay detects determinants on T cells that are expressed below the detection threshold of immunofluorescence. Moreover, these findings indicate that the cellular specificities of a particular Mab may change when one assay system is substituted for another or when the protocol of a particular assay is altered.     

Human polyspecific immunoglobulin attenuates group A streptococcal virulence factor activity and reduces disease severity in a murine necrotizing fasciitis model

Objectives

Streptococcus pyogenes causes life-threatening invasive infections including necrotizing fasciitis (NF). Current treatment guidelines recommend the use of a cell-wall–active antibiotic combined with a protein synthesis inhibitor and surgical debridement in NF patients. Adjunctive therapy with intravenous immunoglobulin (IVIG) has been proposed for superantigen-associated streptococcal toxic shock syndrome. So far, benefits of IVIG treatment remain unclear and prospective clinical studies are scarce. Thus, we aimed to assess the effects of IVIG on virulence factor activity in vitro, ex vivo in patients and in vivo in a NF mouse model.

Correlation-based decomposition of surface electromyograms at low contraction forces

The paper studies a surface electromyogram (SEMG) decomposition technique suitable for identification of complete motor unit (MU) firing patterns and their motor unit action potentials (MUAPs) during low-level isometric voluntary muscle contractions. The algorithm was based on a correlation matrix of measurements, assumed unsynchronised (uncorrelated) MU firings, exhibited a very low computational complexity and resolved the superimposition of MUAPs. A separation index was defined that identified the time instants of an MU's activation and was eventually used for reconstruction of a complete MU innervation pulse train. In contrast with other decomposition techniques, the proposed approach worked well also when the number of active MUs was slightly underestimated, if the MU firing patterns partly overlapped and if the measurements were noisy. The results on synthetic SEMG show 100% accuracy in the detection of innervation pulses down to a signal-to-noise ratio (SNR) of 10 dB, and 93±4.6% (mean± standard deviation) accuracy with 0 dB additive noise. In the case of real SEMG, recorded with an array of 61 electrodes from biceps brachii of five subjects at 10% maximum voluntary contraction, seven active MUs with a mean firing rate of 14.1 Hz were identified on average.     

A probabilistic approach to measure the strength of bone cell adhesion to chemically modified surfaces

Patterned surfaces with alternating regions of amino silanes [N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane (EDS)] and alkyl silanes [dimethyldichlorosilane (DMS)] have been used to alter the kinetics of spatial distribution of cellsin vitro. In particular, we have previously observed the preferential spatial distribution of bone cells on the EDS regions of EDS/DMS patterned surfaces (10). In this study, we examined whether the mechanism of spatial distribution of cells on the EDS regions was adhesion mediated. Homogeneous layers of EDS and DMS were immobilized on quartz substrates and characterized by contact angle, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry. The strength of bone cell attachment to the modified substrates was examined using a radial flow apparatus, within either 20 min or 2 hr of cell incubation in the presence of serum. A Weibull distribution was chosen to characterize the strength of cell-substratum adhesion. Within 20 min of cell exposure, the strength of adhesion was significantly larger on EDS and clean surfaces, compared with DMS surfaces (p<0.0001). Within 2 hr of cell incubation, there was no statistical difference between the strength of cell adhesion to EDS, DMS, and clean surfaces. The results of this study suggest that the surface chemistry mediates adhesion-based spatial cell arrangement through a layer of adsorbed serum proteins.     

Successful treatment of chronic idiopathic urticaria and angioedema with cimetidine alone

We have studied a 50-year-old white man with chronic urticaria and angioedema who has responded to treatment with cimetidine alone for over 2 yr. In a double-blind, placebo-controlled study, cimetidine alone was at least as effective as chlorpheniramine in relief of urticaria and angioedema. Additionally, cimetidine significantly inhibited (p less than 0.01) the wheal response to histamine when it was compared to placebo. The inhibition of wheal response to histamine by cimetidine was significantly higher (p less than 0.05) than chlorpheniramine. The presence of predominantly H2- rather than H1-histamine receptors in the cutaneous blood vessels may be responsible for the therapeutic effects of cimetidine in this patient.