Localization of surface vWF on resting and stimulated platelets

We used immunoelectron microscopic localization techniques to investigate whether platelets stimulated by ADP or ristocetin in the plasma milieu bind von Willebrand factor (vWF) to their surfaces. We found by both peroxidase- and ferritin-based methods that unstimulated platelets lack vWF on their surfaces, whereas platelets that are stimulated with ADP or ristocetin have vWF associated with their surfaces. The specificity of the findings was confirmed by absorption studies using severe von Willebrand disease (vWD) and hemophilic plasmas. The anti-vWF antibodies were blocked by incubation with hemophilic plasma but not by incubation with severe vWD plasma. Thus, in the plasma environment, in the presence of fibrinogen, vWF becomes associated with the platelet surface subsequent to stimulation with ADP or ristocetin.     

External amebocytes guard the pharynx entry in a tunicate (Ascidiacea)

In the present report, we describe the identification of unusual free amebocytes, completely exposed to seawater, which inhabit the inner surface of the oral and atrial siphons of the compound ascidian Botryllus schlosseri (Urochordata). The origin and biological role of these cells were studied by cytochemical and ultrastructural analysis. These amebocytes are mononucleate cells, with numerous round granules, varying in content, and long filopodia, which contact the cuticle protrusions of the tunic in the siphon. Histochemical, histoenzymatic and immunohistochemical assays were carried out under light microscopy on sections and on living and fixed cultured hemocytes. Results showed that the phagocytic blood cells and the free amebocytes of the siphons shared: (i) affinity for the alpha-mannose specific agglutinin of Narcissus pseudonarcissus (NPA), (ii) occurrence of hydrolytic activities of acid phosphatase and non-specific esterases inside lysosomal vesicles and large vacuoles, (iii) membrane labeling with the lipophilic dye PKH26 specific for phagocytic cells, (iv) anti-CD39 immunocytochemical labeling specific for lysosomes of mammalian macrophages. All histochemical data support the hypothesis that these cells are 'sentinel cells' belonging to the hyaline amebocyte population of the phagocytic differentiation line of the immunocytes, since they can also recognize and phagocytize carmine experimentally administered as target particles.     

ADA与EASD对2型糖尿病高血糖处理：治疗启动与评定的新共识方案

在不到一年时间由同一批专家代表ADA和EASD先后起草和发布了两次关于“2型糖尿病高血糖处理的共识声明”同时发表在2008年1月和12月的《DiabetesCare》和《Diabetologia》上。第一次共识声明内容主要围绕TZDs药物的安全性,本刊作了摘译转载（参阅《中国糖尿病杂志22008年第7期）。第二次修订的共识声明,关注点为降糖药的新分级,论据及观点比较清晰,故仍摘译供读者参考。     

First mutation in the voltage-gated NaV1.1 subunit gene SCN1A with co-occurring familial hemiplegic migraine and epilepsy

Almost all mutations in the SCN1A gene, encoding the α₁ subunit of neuronal voltage-gated Na_V1.1 sodium channels, are associated with severe childhood epilepsy. Recently, two mutations were identified in patients with pure familial hemiplegic migraine (FHM). Here, we identified a novel SCN1A L263V mutation in a Portuguese family with partly co-segregating hemiplegic migraine and epilepsy. The L263V mutation segregated in five FHM patients, three of whom also had epileptic attacks, occurring independently from their hemiplegic migraine attacks. L263V is the first SCN1A mutation associated with FHM and co-occurring epilepsy in multiple mutation carriers, and is the clearest molecular link between migraine and epilepsy thus far. The results extend the clinical spectrum associated with SCN1A mutations and further strengthen the molecular evidence that FHM and epilepsy share, at least in part, similar molecular pathways.     

Biocompatibility and biofouling of MEMS drug delivery devices

The biocompatibility and biofouling of the microfabrication materials for a MEMS drug delivery device have been evaluated. The in vivo inflammatory and wound healing response of MEMS drug delivery component materials, metallic gold, silicon nitride, silicon dioxide, silicon, and SU-8(TM) photoresist, were evaluated using the cage implant system. Materials, placed into stainless-steel cages, were implanted subcutaneously in a rodent model. Exudates within the cage were sampled at 4, 7, 14, and 21 days, representative of the stages of the inflammatory response, and leukocyte concentrations (leukocytes/microl) were measured. Overall, the inflammatory responses elicited by these materials were not significantly different than those for the empty cage controls over the duration of the study. The material surface cell density (macrophages or foreign body giant cells, FBGCs), an indicator of in vivo biofouling, was determined by scanning electron microscopy of materials explanted at 4, 7, 14, and 21 days. The adherent cellular density of gold, silicon nitride, silicon dioxide, and SU-8(TM) were comparable and statistically less (p<0.05) than silicon. These analyses identified the MEMS component materials, gold, silicon nitride, silicon dioxide, SU-8(TM), and silicon as biocompatible, with gold, silicon nitride, silicon dioxide, and SU-8(TM) showing reduced biofouling.     

Characterization of four N-3-thymidine adducts formed in vitro by the reaction of thymidine and butadiene monoxide

Four products were characterized from the reaction of thymidine with butadiene monoxide (BM), a known human mutagen and possible human carcinogen. These products were purified by HPLC and characterized as diastereomeric pairs of N-3-(1-hydroxy-3-buten-2-yl)thymidine and N-3- (2-hydroxy-3-buten-1-yl)thymidine based upon their UV spectra, 1H NMR and fast atom bombardment mass spectra. Incubation of thymidine with an excess of BM at pH 7.4 and 37 degrees C allowed calculation of the pseudo-first-order kinetic rate constants for the adduct formation, but when these rate constants were compared with the rates we previously determined with guanosine, adenosine and deoxycytidine, the results suggested a lower reactivity with thymidine in comparison with the other nucleosides. When incubations were carried out at lower BM concentrations, the formation of adducts appeared to be linearly dependent on BM concentration. The four thymidine adducts were completely stable for 1 week when incubated at 37 degrees C in pH 7.4 phosphate buffer. These results suggest that the interactions of BM with thymidine may play a role in the molecular mechanisms of mutagenesis and carcinogenesis of BM.