MK2 plays an important role for the increased vascular permeability that follows thermal injury

We previously reported Rho kinase is involved in vessel hyper-permeability caused by burns. Here we further explore the Rho kinase downstream signaling, it is found that its specific inhibitor Y27632 significantly diminishes the activation of JNK and p38 MAPKs but not ERK that induced by serum from burned rats (burn-serum). JNK activation was found involved in the expression of HUVEC adhesion molecules following thermal injury, although not in the process of stress fiber formation. Inhibition of various MAPKs by specific inhibitors showed that SB203580 (inhibitor of p38), but neither SP600125 (inhibitor of JNK) nor PD98059 (inhibitor of ERK), abolish activation of the p38 downstream kinase MK2. Demonstration of stress fibers by fluorescent-labeled phalloidin showed that inhibition of MK2, either by its specific inhibitor or by dominant negative adeno-viral-carried constructs, significantly reduced burn-serum-induced HUVEC stress-fiber formation, while inhibition of another downstream p38 MAPK kinase, PRAK, had no such effects. Transfection of dominant negative adeno-viral MK2 (Ad-MK2(A)) significantly inhibited thermal injury-induced blood vessel hyper-permeability in rats and, moreover, prolonged the survival of burned rats beyond 72 h following thermal injury. One of the mechanisms behind these phenomena is that Ad-MK2(A) causes a significant depression of burn-serum-induced HSP27-phosphorylation, while the adeno-viral transported dominant negative PRAK (Ad-PRAK(A)) does not block. Although the effect of blockade of MK2 through its adeno-viral approach requires further study and investigation of alternatives to know for sure, we may have found a new pathway behind thermal-injury-induced blood vessel hyper-permeability, namely: Rho kinase > p38 > MK2 > HSP27.     

Attention modulates step initiation postural adjustments in Parkinson freezers

BackgroundIn view of freezing of gait's circumstances of occurrence in Parkinson's disease, attentional resources appear to be involved in step initiation failure. Anticipatory postural adjustments (APAs) are essential because they allow unloading of the stepping leg and so create the conditions required for progression.Our main objective was to establish whether or not a change in attentional load during step initiation modulates APAs differently in patients with vs. without freezing of gait.MethodsThree groups of 15 subjects were recruited: elderly people and parkinsonian patients with or without freezing of gait. Attention was modulated before step execution by means of an auditory oddball discrimination task with event-related potential recording. The primary endpoint was the occurrence of inappropriate APAs following the attentional task, i.e. APAs not followed by a step after an intercurrent auditory stimulus.ResultsIn parkinsonian patients with freezing of gait, inappropriate APAs were recorded in 63% of the trials and were observed more frequently than in patients without freezing of gait (51%) and elderly controls (48%). Furthermore, inappropriate APAs in freezers were longer and more ample than in parkinsonian non-freezers and controls. Lastly, postural preparation was impaired in the parkinsonian patients.ConclusionOur results indicate that allocation of attentional resources during step preparation influences the release of APAs differently in freezers and non-freezers. Modulating attentional load is partly responsible for triggering an inappropriate motor program. This difficulty in focusing attention or resisting interference may contribute (at least in part) to the gait initiation failure observed in parkinsonian freezers.     

突变生物合成在微生物药物领域的研究进展

突变生物合成作为产生抗生素衍生物的重要手段，自20世纪70年代兴起以来，发挥了巨大作用，已开发出许多至今在临床上仍广泛使用的抗生素品种。随着基因技术的发展．突变生物合成技术可直接对次级代谢途径中一特定酶基因进行改造获得突变株．大大提高了工作效率和准确性。本文综述了突变生物合成技术在微生物药物领域的应用，特别是结合基因技术进行突变生物合成研究的新进展。     

MBS和戊二醛连接hPTH载体特异抗体及载体抗体的比较研究*

目的:比较间-马来酰亚胺苯甲酸-N-羟基琥珀酰亚胺酯(MBS)和戊二醛连接人甲状旁腺激素(hPTH)载体后抗体的产生效果。方法:MBS法和戊二醛一步法分别将hPTH(1-84)与载体牛血清白蛋白(BSA)连接后作为免疫原免疫家兔;间接ELISA法比较两组兔中特异性hPTH(1-84)抗体和BSA抗体的产生,并使用免疫吸收和亲和层析吸附清除BSA抗体,对清除情况进行比较。结果:MBS组抗hPTH(1-84)抗体效价总体上高于戊二醛组,抗载体BSA抗体效价低于戊二醛组;MBS组在同一时间hPTH(1-84)抗体效价高于BSA抗体,戊二醛组获取的抗血清中BSA抗体效价则明显高于hPTH(1-84)抗体。MBS组经亲和层析吸附BSA抗体被清除完全,戊二醛组经免疫吸收和亲和层析吸附仍有残留BSA抗体。结论:采用MBS法连接半抗原载体制备hPTH(1-84)抗体,降低了载体抗体的影响,提高了hPTH(1-84)抗体的特异性,可应用于hPTH药理作用和代谢途径等研究工作中。     

Thermal gradients in microtitration plates. Effects on enzyme-linked immunoassay

Temperature studies of microtitration plates demonstrate that the use of a common bacteriology incubator for heating the plates can cause a phase lag of over 30 min for the fluid in the wells to reach 37°C from ambient temperature, and that a temperature gradient of as much as 1.6°C can exist between the peripheral and center wells. This gradient is a cause of the ‘rim’ or edge effect noted in enzyme immunoassay using microtitration plates. The problem is corrected by the use of a specially designed forced air microtitration plate incubator.     

Dysphagia dietary guidelines and the rheology of nutritional feeds and barium test feeds

BACKGROUND: Dysphagia can lead to aspiration of oral feeds, thus causing pneumonia. Dysphagia is diagnosed by assessing the ability to swallow barium test feeds (BTF) of different viscosities. Dysphagia diet foods (DDF) are thickened as recommended by the National Dysphagia Diet (NDD) guidelines. To our knowledge, there are no published data evaluating if the viscosity of BTF or commercial DDF meet NDD guidelines. METHODS: A TA1000 rheometer (TA Instruments; New Castle, DE) measured dynamic viscosity of BTF and DDF using creep transformation under controlled stress. Thin DDF studied included Plus Energy Drink (Boost; Novartis/Nestle; Fremont, MI) and Instant Breakfast (Carnation; Wilkes-Barre, PA) and nectar- and honey-thick DDF from Hormel (Hormel Health Labs; Savannah, GA) and Novartis (Novartis/Nestle). The BTF studied were thin, nectar-, and honey-thick Polibar barium suspension or Varibar (E-Z-EM, Inc.; Lake Success, NY). We measured batch-to-batch variability in the viscosity of DDF, with and without shaking, and after 2 h at ambient temperature at a shear rate chosen to match natural swallowing. RESULTS: We observed the following: (1) DDF: the viscosity of honey-thick DDF was consistent with NDD guidelines, but other products were not. All products had minimal change in viscosity over 2 h. Boost thin liquid had > 300% increase in viscosity after shaking. (2) BTF: thin barium had a viscosity consistent with NDD guidelines. The nectar- and honey-thick Polibar BTFs were thixotropic and had unacceptably high viscosity. Varibar BTFs were not thixotropic but were more viscous than the NDD guidelines. CONCLUSIONS: There was a poor relationship between the viscosity of DDF and BTF. The viscosity of BFTs is much greater than the correspondingly named diet foods and the NDD guidelines. This can place patients at significant risk for oral aspiration.     

Simulations and Measurements of Human Middle Ear Vibrations Using Multi-Body Systems and Laser-Doppler Vibrometry with the Floating Mass Transducer

The transfer characteristic of the human middle ear with an applied middle ear implant (floating mass transducer) is examined computationally with a Multi-body System approach and compared with experimental results. For this purpose, the geometry of the middle ear was reconstructed from μ-computer tomography slice data and prepared for a Multi-body System simulation. The transfer function of the floating mass transducer, which is the ratio of the input voltage and the generated force, is derived based on a physical context. The numerical results obtained with the Multi-body System approach are compared with experimental results by Laser Doppler measurements of the stapes footplate velocities of five different specimens. Although slightly differing anatomical structures were used for the calculation and the measurement, a high correspondence with respect to the course of stapes footplate displacement along the frequency was found. Notably, a notch at frequencies just below 1 kHz occurred. Additionally, phase courses of stapes footplate displacements were determined computationally if possible and compared with experimental results. The examinations were undertaken to quantify stapes footplate displacements in the clinical practice of middle ear implants and, also, to develop fitting strategies on a physical basis for hearing impaired patients aided with middle ear implants.     

Immunologic and functional characterization of anti-HLA-DR rabbit antibodies induced by synthetic peptides

Three peptides selected from the amino acid sequence of the alpha- and beta-chains of DR2 histocompatibility antigens were chemically synthesized and coupled to carrier proteins to be used as immunogens in rabbits. This immunization resulted in the production of specific antibodies that readily recognized the antigen. However, only one of the four antibody preparations, antibody 6148, elicited by a short peptide from the beta-chain (residues 61-73), reacts with native membrane glycoproteins as well as intact human lymphoblastoid cells in enzyme-linked immunosorbant assays. This antibody was found to react also with membrane glycoproteins solubilized by nonionic detergents from cells bearing a different HLA-DR specificity: therefore it is likely that the peptide responsible for eliciting antibody 6148 represents a common framework determinant of DR alloantigens that is accessible on the surface of lymphoblastoid cells. The ability of antibody 6148 to bind to intact cells was confirmed by indirect immunofluorescence and by fluorescein-activated cell sorter analysis. This antibody is also capable of mediating antibody-dependent cellular cytotoxicity as determined by a 51Cr-release assay.     

A sensitive enzyme-linked immunosorbent assay for the quantitation of antigen-specific murine immunoglobulin E

An enzyme-linked immunosorbent assay (ELISA) for the quantitation of 2,4-dinitrophenyl (DNP)-specific murine immunoglobulin (Ig) E is described. The assay uses beta-galactosidase, which is conjugated to goat anti-rabbit gamma-globulin (GARG) via a method using a mild heterobifunctional cross-linking reagent, m-maleimidobenzoyl-N-hydroxy-succinimide ester (MBS). The assay has a sensitivity for detection of about 200 pg/ml of anti-DNP IgE. Analyses of murine serum samples using this ELISA correlate well with those obtained using the passive cutaneous anaphylaxis (PCA) reaction in rats. With the use of automated 96-well reader, data acquisition is rapid and, therefore, this ELISA is ideal for analyses of large numbers of samples. The assay can be easily modified for the measurement of other Ig classes and of IgE of other antigen specificities.