Aromatic residues affecting permeation and gating in dSlo BK channels

 Structural determinants of permeation in large unit conductance calcium-activated potassium channels (BK channels) were investigated. Y293 and F294 in the P-region of dSlo were substituted by tryptophans. Compared to wild-type channels, Y293W channels displayed reduced inward unitary currents while F294W channels exhibited normal inward current amplitudes but flickery kinetics. Both mutations produced changes in current/voltage relations under bi-ionic conditions. Sensitivity to block by external tetraethylammonium (TEA) was affected in both channels, and the voltage dependence of TEA block was increased in F294W channels. Both mutations also affected gating by shifting the half-maximal activation voltage of macroscopic conductance/voltage relations to more positive potentials, and eliminating a slow component of deactivation. The double mutant did not produce ionic currents. These data are consistent with a model in which Y293 contributes to a potassium-binding site close to the outer mouth of the dSlo pore, while F294 contributes to an energy barrier near this site. Received: 16 September 1997 / Received after revision: 20 November 1997 / Accepted: 21 November 1997     

Lipopolysaccharide augments IgG and IgE responses of mice to the latex allergen Hev b 5

Background: LPS is a common contaminant in the health care environment and in latex examination gloves. Objective: We sought to investigate the role of LPS in enhancing the immune responses of mice to inhaled latex allergen. Methods: As our model allergen, we used a fusion protein containing the potent latex allergen Hev b 5. BALB/c mice were lightly anesthetized and given repeated intranasal doses of saline, LPS, and/or Hev b 5. The doses were given in 2 courses separated by a 6-week period, with the first course consisting of 6 doses and the second consisting of 3 doses. Results: After the first set of immunizations, mice given Hev b 5 alone had no detectable IgG1 or IgE responses to Hev b 5, whereas mice given the antigen along with LPS had significant responses (IgG1, 0.73 U ± 0.05; IgE, 0.88 U ± 0.2). No enhancement of specific IgG2a was observed. A stimulatory effect of LPS on all 3 immunoglobulin types was apparent after the second course. Lymphocytes from mice immunized with LPS and Hev b 5 had increased proliferation to Hev b 5 and its fusion partner. Conclusions: LPS may be an important immunoadjuvant for the development of allergic reactions to latex protein allergens. (J Allergy Clin Immunol 199;102:977-83.)     

Are HLA-DR or TAP Genes Genetic Markers of Severity in Ulcerative Colitis?

The pathogeny of ulcerative colitis (UC) is not yet elucidated, but some arguments suggest the implication of genetic factors. Among the candidate genes, those encoding for HLA class II genotypes have been extensively studied in UC; however, discordant data may be imputable to heterogeneity, characterized by immunological markers such as atypical ANCA (p-ANCA), or to inclusion of more or less intractable UC. The aim of our study is to evaluate the interest of HLA class II and TAP genetic markers to identify different clinical forms of UC, according to p-ANCA status. Unrelated patients with a history of UC (n=91) and healthy control subjects with no personal or family history of inflammatory bowel diseases (IBD) (n=200) were included. HLA-DRB103 was less frequent in UC patients than in healthy controls (8% vs 28%,PC<0.03). No association was found with any TAP genotypes. Moreover, there was no association with the HLA-DR2 specificity, either in the entire group of UC patients (38% vs 28%) or in the p-ANCA-positive subgroup of patients (30%). The most consistent finding in the present study is that some genetic markers may characterize intractability in UC patients. HLA-DR2 was associated with poor prognosis, regardless of p-ANCA status. In HLA-DR2 and non-HLA-DR2 groups, colectomy was done in 55% and 27% of patients, respectively (PC<0.05). Furthermore, in non-HLA-DR2 patients, p-ANCA could be of interest to characterize those with more severe prognosis. Our results confirm the interest of genetic studies to define UC genetic susceptibility, taking into account intractability of the disease. They do not support the hypothesis that p-ANCA is a subclinical marker of genetic susceptibility to UC.     

Existence of a small population of IL-2Rβhi TCRint cells in SCG and MRL-lpr/lpr mice which produce normal Fas mRNA and Fas molecules from the lpr gene

Mice carrying the lpr gene, SCG and MRL-lpr/lpr mice, were used to characterize the phenotype and lpr gene of abnormally proliferating T cells in these mice. A major population which expanded in these mice were T cells expressing intermediate (int) levels of T cell receptor (TCR) (and CD3) and the phenotype of interleukin-2 receptor (IL-2R)β^lo α^? (possibly abnormal TCR^int cells). The levels of TCR^hi cells of thymic origin (generated through the mainstream of T cell differentiation in the thymus) profoundly decreased after the onset of disease. However, a small population of normal TCR^int cells (i.e. IL-2Rβ^hi α^?) were also found to exist in all tested organs. For example, the majority of abnormal IL-2Rβ^lo TCR^int cells were CD4^?8^? CD2^?, while normal IL-2Rβ^hi TCR^int cells were a mixture of single-positive cells (mainly CD8⁺), CD4^?8^? cells and CD2⁺ cells. Moreover, normal TCR^int cells preferentially produced normal Fas mRNA and Fas molecules from the lpr gene. This phenomenon explains the leaky appearance of normal Fas mRNA and Fas molecules in mice carrying the lpr gene. It is suggested that a small population of IL-2Rβ^hiTCR^int cells are resistant to the lpr genetic abnormality.     

Prevention of endotoxin shock by an antibody against leukocyte integrin {beta}2 through inhibiting production and action of TNF

Septic shock remains a serious disorder associated with highmortality. Accumulating evidence indicates that TNF is a majorand essential mediator of endotoxin shock. We report here thatadministration of an antibody against CD18 dramatically reducedendotoxin-induced shock inrabbits as revealed by preventionof severe hypotension, metabolic acidosis and a pathologicalchange suggestive of disseminated intravascular coagulationwith concomitant inhibition of elevation of plasma TNF activity.The anti-CD18 antibody also inhibited the hypotension inducedby administering recombinant TNF. Furthermore, an antibody againsta ligand for CD18 complexes, intercellular adhesion molecule-1,also prevented TNF-induced shock as well as endotoxin shockinrabbits. These observations suggest that adhesion of leukocytesto endothelium may be of primary importance in the action ofTNF as well as in the production of TNF in vivo and that theantibody against adhesion molecules could be of therapeuticbenefit in life-threatening septic shock in humans.     

中药蜈蚣对小鼠胚胎发育的影响

孕鼠１６１只随机分组，在孕期第７－１１天给实验组分别以５００ｍｇ／（ｋｇ．ｄ）（蜈蚣１组）及１０００ｍｇ／（ｋｇ．ｄ）（蜈蚣２组）的中药蜈蚣煎剂灌胃，至孕期１８天记录各组孕鼠和胎鼠的发育情况。结果表明：蜈蚣１，２两组致畸作用明显，死胎，吸收胎比例升高；蜈蚣２组胎鼠和孕鼠的体重均下降，堕胎作用显著，与对照组比较，差异均有非常显著意义（Ｐ＜０．０１）。     

Integrative transformation of the mycotoxin-producing fungus,Penicillium paxilli

A high frequency transformation system has been developed for Penicillium paxilli using pAN7-1. Up to 44% of the primary transformants were heterokaryons. Loss of hygromycin resistance was observed in primary transformants that were sub-cultured on non-selective media, but single spores of these primary transformants were mitotically stable on both selective and non-selective media. A molecular analysis of the transformants generated showed that 78% had single-site integrations, with half of these containing a single copy of pAN7-1. CHEF-gel electrophoresis showed that P. paxilli has at least six chromosomes with a total genome size of about 23.4 Mb.     

Bilateral salpingectomy does not compromise ovarian stimulation in an in-vitro fertilization/embryo transfer programme

The question whether salpingectomy has a negative influenceon ovarian function and the outcome of pregnancy in an in-vitrofertilization (IVF) and embryo transfer treatment programmeis not yet answered. We performed a retrospective case-controlstudy to investigate the possible negative effect of salpingectomyon ovarian response to human menopausal gonadotrophins (HMG)during IVF and embryo transfer. The study group was composedof 26 patients with bilateral salpingectomy. In 67 cycles weanalysed different parameters of ovulation such as the numberof days of ovarian stimulation, numbers of ampoules of HMG,pre-ovulatory oestradiol concentrations and the numbers of oocytesretrieved. These parameters were compared to a control groupof 134 cycles in 134 women with healthy Fallopian tubes. Nodifferences were found. Implantation ratio, pregnancy rate andoutcome were the same in both groups. We conclude that bilateralsalpingectomy had no detrimental effect on ovarian performanceduring IVF and embryo transfer treatment nor on the outcome.     

Generation and Regulation of CD8＋ Regulatory T Cells

Research into the suppressive activity of CD4＋FoxP3＋ T regulatory cells （Treg） has defined a sublineage of CD4＋ cells that contribute to self-tolerance and resistance to autoimmune disease. Much less attention has been given to the potential contribution of regulatory sublineages of CD8＋ cells. Analysis of a small fraction of CD8＋ cells that target autoreactive CD4＋ cells through recognition of the MHC class Ib molecule Qa-1 in mouse and HLA-E in human has revitalized interest in CD8＋ Treg. Here we summarize recent progress and future directions of research into the role of this CD8＋ sublineage in resistance to autoimmune disease. Cellular ＆ Molecular Immunology. 2008; 5（6）：401-406.