Development of an ELISA for detection of an organophosphorus compound using monoclonal antibodies

This paper describes a specific and highly sensitive ELISA system using monoclonal antibodies in order to assay an organophosphorus compound. The soman derivative methyl phosphonic acid, p-aminophenyl 1,2,2,-trimethyl-propyl diester (MATP) served as model substance. In order to obtain antibody-producing hybridomas BALB/c mice were immunized with MATP linked onto human serum albumin (HSA). The spleen cells of immunized mice were fused with syngenic plasmacytomas of the non-producer-line X63Ag8.653 with the aid of polyethylene glycol. To eliminate undesirable cross-reaction, common screening procedures were modified by directly coating the ELISA plates with hapten. Five out of 15 positive cell-lines were cloned by limiting dilution and further propagated. The respective immunoglobulin class and subclass of the obtained monoclonal antibodies was determined. Four of which were identified as IgG₁, the other as IgG_2a. After enrichment of antibodies in ascites and their isolation by protein A-sepharose, the affinity of various monoclonal antibodies was estimated in competitive inhibition enzyme immunoassay (CIEIA) by measuring the IC₅₀ rates of free MATP. The rates were found to lie between 2.5 × 10^–6 mol/l and 4.3 × 10^–4 mol/l MATP. The IC₁₀ rate for detectable MATP concentration was 5.4 × 10^–7 mol/l MATP. Test duration was 280 min. The reactivity of the monoclonal antibodies with structurally related substances was used to check their specificity. Cross-reaction turned out to be negative. In order to develop a direct competitive ELISA, MATP was linked to horse radish peroxidase (HRPO) by adding a spacer. This helped to reduce total duration to 40 min. The detection level was further reduced to 1.3 × 10^–7 mol/l MATP (corresponding to 975 pg/25 l test-buffer) using the monoclonal antibody F71D7. Likewise, MATP was detected in goat serum, chicken serum, rabbit serum, milk and company's water in concentrations between 2.1 × 10^–7 mol/l (IC₁₀, company's water) and 4.9 × 10^–8 mol/l (IC₁₀, milk).     

How sensitive is hand transport to illusory context effects?

A recent report that hand transport was sensitive to a size-contrast illusion (SCI) implied that the distinction between visual processing for perception versus action might only affect visual information obtained late during reaching. In this study, the presence of a perceptual SCI did not affect reaction time, movement time, or movement amplitude. However, both perception and action became sensitive to the SCI with memory-based responses. It is concluded that the distinction between visual processing for perception versus action does extend to hand transport. Immediate action is entirely based on veridical visuo-motor representations, whereas even slightly delayed actions begin to reflect distorted perceptual representations.     

Caffeine potentiation of mefenamic acid-induced lesions in the rat renal medulla.

The effect of caffeine given in combination with mefenamic acid on the renal medulla was examined. Sprague-Dawley rats were divided into four groups and gavage fed either vehicle suspension (control), mefenamic acid, mefenamic acid+caffeine or caffeine only for 4 months. Renal tissue taken from the corticomedullary junction was processed for electron microscopy. Ultrathin sections were cut after identification of vasa rectae on survey sections. On subsequent morphometric analysis, percentage interstitial tissue was calculated from the total area of vasa recta less the non-interstitial tissue. The median percentage of interstitial tissue in the mefenamic acid and caffeine group was 41 (range 33-50; n = 15) compared with 34 (20-48; n = 20) in mefenamic acid (P less than 0.01), 29 (15-42; n = 15) in caffeine only (P less than 0.001) and 32 (20-46; n = 18) in vehicle-treated animals (P less than 0.001). There were no significant differences between mefenamic acid alone and vehicle or caffeine-only groups or between caffeine-only and vehicle-treated controls. This suggests that caffeine potentiates the effect of the non-steroidal anti-inflammatory drug, mefenamic acid, on the rat renal medulla, resulting in a quantitative increase in the interstitial tissue between adjacent afferent and efferent vasa recta.     

Diagnosis of iodinated contrast media hypersensitivity: results of a 6-year period

Background Iodinated contrast media (ICM) hypersensitivity reactions represent a serious problem. Very few clinical data concerning systematic skin testing to ICM are available. Objective To evaluate the utility of ICM skin testing in patients with ICM hypersensitivity. Material and methods All patients referred over a 6‐year period for ICM hypersensitivity past reactions were skin tested for (a) the implicated ICM, or (b) a set of ICM if they were positive for the implicated ICM or if its name was unknown. Results Forty‐four patients, with a median age of 56 years, were studied (15 males, 29 females). The ICM skin tests were positive in 10 patients (23%): one had a positive skin prick test, seven an immediate positive intradermal test (IDT) and two a delayed positive IDT. Skin tests were more often positive in patients with immediate (9/32) as compared with those with non‐immediate reactions (1/11). The time interval between the reaction and skin testing was shorter for those patients with an immediate ICM reaction and a positive skin test result (3 months [2.5–174.0]) as compared with those with an immediate ICM reaction and a negative skin test (48 months [6.8–159.0]), (P<0.05). Respiratory allergy was more frequent in the positive group (6/10 vs. 7/34, P<0.05). Conclusions Skin tests with ICM are positive in a subgroup of patients with ICM hypersensitivity and may play an important role in the diagnosis of ICM allergy.     

超声波介导的基因输送技术

近年来超声波介导的基因输送技术由于其相对安全性和操作上的简单得到关注。本文对超声波导致的声致穿孔的机制,空化核的作用——增强基因输送的效率,以及细胞和在体基因输送效率作了综述,讨论了超声波介导的基因输送效率的影响因素。此方法充满希望并且载药的空泡可以作为一种新型药物载体在超声作用下实现药物的靶向输送     

透析法去除红细胞渗透性低温保护剂的实验研究

要实现人类红细胞深低温保存,必须在冷冻前添加、复温后去除低温保护剂.本研究提出了低温保护剂的新型的透析去除法,与常规的离心洗涤法比较而言,该方法能够快速、有效、安全地去除红细胞内的低温保护剂(甘油).使用该方法冰冻.复温.洗涤后的红细胞计数回收率为(89.17±2.46)%,血红蛋白回收率为(84.93±4.64)%,上清游离血红蛋白的含量为(0.66 ±0.13)g/L,所得冰冻-复温-洗涤后的红细胞悬液的渗透压(残余甘油的含量)为(340.33±20.56)mOsm,均达到了国家对冰冻洗涤红细胞的质量标准要求.     

Chromatin interactions in differentiating keratinocytes reveal novel atopic dermatitis– and psoriasis-associated genes

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Central nervous system inflammatory response after cerebral infarction as detected by magnetic resonance imaging

Brain inflammation contributes to the tissue injury caused by ischemic stroke. Macrophages as the most abundant inflammatory cell population in stroke lesions can be visualized using ultrasmall superparamagnetic iron oxide (USPIO) as a cell-specific contrast agent for magnetic resonance imaging (MRI). The aim of our present study was to delineate the inflammatory response during experimental cerebral infarction by means of USPIO-enhanced MRI and to correlate the spatial distribution of USPIO-induced MR signal alterations with cellular infiltration and iron deposition. To this end USPIOs were administered to Wistar rats 5 days after photothrombotic cerebral infarction. MR imaging at 7 T performed 24 h later displayed a rim-like signal loss around the infarction in the USPIO treated animals. On histological brain sections obtained from the same animals after MRI the distribution of iron and ED1+ phagocytes was in full spatial agreement with the signal loss seen on T2*-weighted images. Our study validates USPIO-enhanced MRI as an important tool for the noninvasive visualization of brain inflammation in stroke and other CNS pathologies.     

Isolation of a peptide inhibitor of human rhinovirus

Cell culture-based transdominant genetic techniques provide new methods for discovering peptide/RNA modulators of cellular pathways. We applied this technology to isolate a peptide inhibitor of human rhinovirus. A green fluorescent protein (GFP)-scaffolded library of cDNA fragments was expressed in HeLa cells from a retroviral vector and screened for inhibitors of rhinovirus-mediated cell killing. A DNA clone, I421, increased cell survival in an HRV14 challenge assay from less than 0.5% to greater than 60%. It encodes a 53-amino-acid C-terminal extension of the GFP scaffold. Particular subclones of Hela cells expressing I421 (exemplified by I421dp3) show a delay in virus production and a 50-fold decrease in viral RNA levels at 6-8 h postinfection. HRV2, HRV14, and HRV16 show a dramatic decrease in plaque-forming ability on I421dp3 while Coxsackievirus B3 showed a small reduction. Levels of ICAM-1, the receptor for the main rhinovirus serotype, are not altered in I421dp3.     

Assessment of PACS Display Systems

This work describes our experience in reviewing the performance criteria for display systems and how we have implemented a practical approach to the assessment of the workstation environment in a large tertiary care hospital. The acceptance criteria contained in the draft report of Topic Group 18 of the American Association of Physicists in Medicine (AAPM) were used as a basis for assessment of primary and secondary displays. A telescopic photometer was used to measure the maximum luminance and the contrast ratio of the image for the displays used in our radiology department and in the operating and emergency rooms using the standard Society of Motion Picture and Television Engineers (SMPTE) pattern, in ambient light and with light decreased as much as possible. About half of the displays met the AAPM criteria for minimum luminance and contrast ratio in low light. None of the systems met the contrast ratio criteria in ambient light. The challenges in improving the performance and calibrating displays are discussed.