The final destiny of acantholytic cells in pemphigus is Fas mediated

Background  Pemphigus is an autoimmune disease characterized by the formation of intra-epidermal blisters. Patients develop auto-antibodies against desmoglein 1 and 3 proteins and induce acantholysis.
Objective  This work addresses the issue of whether the Fas pathway mediates acantholysis. Furthermore, the possible suppliers of the Fas pathway were investigated.
Methods  Seventeen biopsies of pemphigus patients were studied by haematoxylin and eosin staining, and apoptosis was defined by TUNEL. The expression of Fas, FasL and caspase 3 was studied by in situ hybridization and immunohistochemistry. Cell infiltrates were studied by immunofluorescence with monoclonal anti-CD3, CD4, CD8, CD19 and CD69.
Results  All of the biopsies showed intra-epidermal blisters, acantholytic cells and inflammatory infiltrates. The blisters expressed Fas, FasL and caspase 3. Cell infiltrates were composed of CD8 and a few CD4⁺CD69⁺ cells. Additionally, CD19⁺ cells were detected. Interestingly, the Fas expression was increased in acantholytic cells and perilesional keratinocytes. Incidentally, these cells exhibited apoptotic features. Interestingly, the CD8 cells expressed FasL.
Conclusion  This paper presents the morphological evidence that apoptosis and acantholysis are linked. Therefore, the Fas pathway is associated with CD8 cells in pemphigus lesions.

Conflicts of interest

None declared.     

ROLE OF NITRIC OXIDE IN THE DEVELOPMENT OF CORTICOTROPIN-INDUCED HYPERTENSION IN SHEEP

1. The possibility that altered synthesis of vascular nitric oxide (NO) plays a role in the development of corticotropin-induced hypertension in sheep was examined by determining the effect of concomitant infusion of L-arginine, a precursor of NO, on the development of the hypertension. 2. Corticotropin (5 μg/kg per h) infused over 2 days increased mean arterial pressure (MAP) from 83 ± 4 to 99 ± 4 mmHg in five conscious sheep. Concomitant infusion of L-arginine (60 mg/kg per h) did not alter this response; infusion of L-arginine alone had no effect on blood pressure. 3. The dose of L-arginine (60 mg/kg per h) used blocked the rise in MAP (+16 mmHg) in response to a 5 h infusion of N-nitro-L-arginine (1 mg/kg per h). 4. These findings suggest that disruption of NO synthesis does not play a role in the development of corticotropin hypertension in sheep.     

A reversible monoamine oxidase inhibitor, toloxatone: Structural and electronic properties

Toloxatone is a reversible MAO_A-inhibitor, marketed as antidepressant (Humoryl^®), with an original chemical structure. It differs from first generation irreversible MAOIs, known to induce covalent bonds with the enzyme active site. In order to understand the mechanism of the reversible inactivation of the MAO, as a first step, a detailed structural and electronic analysis was undertaken. An X-ray diffraction-crystallographic study showed that toloxatone is a planar molecule and brought to light hydrogen bonds and π-π interactions. MO calculations confirmed the planar structure as energetically favoured. Electronic analysis demonstrated a delocalization of both ring systems. The combined results give evidence for the potential of toloxatone to participate in reversible, long distance interactions with an appropriate partner.     

Fixed drug eruption from piroxicam

The pathogenetic mechanism of fixed drug eruption (FDE) is still unknown. One of the most common causes of FDE is the use of nonsteroidal antiinflammatory drugs (NSAIDs). Oxicams are in the NSAID group and piroxicam is one of the most used of these drugs. FDE caused by piroxicam is rare but a few cases have been reported. Patch tests are useful for diagnosing some cases of FDE; they give variable results on previously affected skin while no reaction appears on unaffected skin. Some cases of cross-sensitivity among piroxicam and other substances have been reported. We report two new cases of FDE due to piroxicam with negative patch test on normal skin and positive results on affected skin.     

鼠尾静脉流体力学转染技术对绿色荧光蛋白表达质粒器官靶向分布的影响

目的:观察流体力学尾静脉注射对绿色荧光蛋白基因器官靶向性的影响,为今后质粒载体的基因治疗和功能研究寻找潜在的靶器官。方法:实验于2005-12/2006-04在江西省分子医学重点实验室完成。选用健康雄性昆明鼠40只,将32只小鼠按随机数字表法分为流体力学注射和常规注射两大组,每大组再分为转染组和对照组两个小组(n=8),并设正常对照组(n=8)。①流体力学转染组将100μg/只绿色荧光蛋白表达质粒溶液2mL在5s内快速注入尾静脉;对照组仅在5s内注入林格氏液2mL。②常规注射组则将2mL林格氏液或绿色荧光蛋白表达质粒溶液在30s左右注入尾静脉。注射结束后24h采集各组小鼠血清检测转氨酶,并采集肝、脾、心、肾、肺和脑组织进行冰冻切片,部分肝组织采用多聚甲醛固定后切片,荧光显微镜下观察。结果:40只小鼠全部进入结果分析,无脱失。①流体力学注射组和常规注射组小鼠血清转氨酶与正常对照组比较差异均无显著性意义(P>0.05)。②常规尾静脉注射引起少数肾小球细胞表达绿色荧光蛋白,而肝、脾、心、肺及脑等组织未见明显绿色荧光蛋白表达。③流体力学注射引起肝内绿色荧光蛋白高水平表达,肝细胞表达率接近45%,其他组织则无绿色荧光蛋白表达。结论:流体力学方法是肝靶向性的活体基因转染方法,绿色荧光蛋白可作为该方法进行目的基因研究的一个可靠和方便的示踪剂。     

The lipoprotein-associated coagulation inhibitor that inhibits the factor VII-tissue factor complex also inhibits factor Xa: insight into its possible mechanism of action

Blood coagulation is initiated when plasma factor VII(a) binds to its essential cofactor tissue factor (TF) and proteolytically activates factors X and IX. Progressive inhibition of TF activity occurs upon its addition to plasma. This process is reversible and requires the presence of VII(a), catalytically active Xa, Ca2+, and another component that appears to be associated with the lipoproteins in plasma, a lipoprotein-associated coagulation inhibitor (LACI). A protein, LACI(HG2), possessing the same inhibitory properties as LACI, has recently been isolated from the conditioned media of cultured human liver cells (HepG2). Rabbit antisera raised against a synthetic peptide based on the N-terminal sequence of LACI(HG2) and purified IgG from a rabbit immunized with intact LACI(HG2) inhibit the LACI activity in human serum. In a reaction mixture containing VIIa, Xa, Ca2+, and purified LACI(HG2), the apparent half-life (t1/2) for TF activity was 20 seconds. The presence of heparin accelerated the initial rate of inhibition threefold. Antithrombin III alpha alone had no effect, but antithrombin III alpha with heparin abrogated the TF inhibition. LACI(HG2) also inhibited Xa with an apparent t1/2 of 50 seconds. Heparin enhanced the rate of Xa inhibition 2.5-fold, whereas phospholipids and Ca2+ slowed the reaction 2.5-fold. Xa inhibition was demonstrable with both chromogenic substrate (S-2222) and bioassays, but no complex between Xa and LACI(HG2) could be visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Nondenaturing PAGE, however, showed that LACI(HG2) bound to Xa but not to X or Xa inactivated by diisopropyl fluorophosphate. Thus, LACI(HG2) appears to bind to Xa at or near its active site. Bovine factor Xa lacking its gamma-carboxyglutamic acid-containing domain, BXa(-GD), through treatment with alpha-chymotrypsin, was used to further investigate the Xa requirement for VIIa/TF inhibition by LACI(HG2). LACI(HG2) bound to BXa(-GD) and inhibited its catalytic activity against a small molecular substrate (Spectrozyme Xa), though at a rate approximately sevenfold slower than native BXa. Preincubation of LACI(HG2) with saturating concentrations of BXa(-GD) markedly retarded the subsequent inhibition of BXa. The VII(a)/TF complex was not inhibited by LACI(HG2) in the presence of BXa(-GD), and further, preincubation of LACI(HG2) with BXa(-GD) slowed the inhibition of VIIa/TF after the addition of native Xa. The results are consistent with the hypothesis that inhibition of VII(a)/TF involves the formation of a VIIa-TF-XA-LACI complex that requires the GD of XA.(ABSTRACT TRUNCATED AT 400 WORDS)     

Richter's syndrome with different immunoglobulin light chains and different heavy chain gene rearrangements

In a patient with Richter's syndrome, the chronic lymphocytic leukemia (CLL) expressed lambda, mu, and delta immunoglobulin (lg) chains and the non-Hodgkin lymphoma (NHL) kappa, mu, and delta lg chains. The difference in lg light chain expression suggests that the CLL and NHL are independent malignancies, or that the oncogenic event occurred in a B cell differentiation stage after the heavy chain gene rearrangements but before the selection of the light chain. Analysis of DNA by Southern blotting revealed that the lg heavy chain genes of the two malignancies were rearranged in a different way. We therefore conclude that in this patient the NHL cannot be regarded as a progression of the CLL but should most likely be considered as an independent B cell malignancy, which arose in a susceptible host.     

Role of arginine residues in the coagulant activity of high molecular weight kininogen

High molecular weight (HMW) kininogen, the cofactor for activation of the contact system of plasma proteolysis, transports and optimally positions prekallikrein and factor XI on a negatively charged surface, allowing those zymogens to be activated by surface-bound factor XIIa. HMW kininogen circulates in plasma as a procofactor that, after cleavage by kallikrein or factor XIIa, gains ability to bind to the surface. The mechanism responsible for this increased affinity for the surface is unknown. We hypothesized that modification of arginine residues may prevent cleavage of HMW kininogen, since the initial kallikrein-induced cleavage sites on the HMW kininogen molecule are at the NH2 terminal and the COOH terminal of the bradykinin-containing portion of the molecule, each of which contains arginine. We found that modification with butanedione of four arginine residues in the HMW kininogen molecule prevented bradykinin release, which results from cleavage of HMW kininogen. Furthermore, HMW kininogen coagulant activity was lost, in proportion to the degree of arginine modification, until 6.6 residues had been modified. Complex formation with prekallikrein, however, was found to be uneffected by the modification of modified HMW kininogen. To account for the loss of coagulant activity, we also examined the ability of modified HMWKa (active cofactor) to bind to an activating surface. The affinity of modified HMWKa for kaolin was tenfold less than the affinity of unmodified HMWKa. These data suggest that arginine residues play a critical role in the ability of HMW kininogen to function as an activation cofactor, both by preventing the cleavages that produce HMWKa as well as by decreasing the affinity of HMWKa for the surface.