E12 technique: Conventional epoxy resin sheet plastination

Epoxy plastination techniques were developed to obtain thin transparent body slices with high anatomical detail. This is facilitated because the plastinated tissue is transparent and the topography of the anatomical structures well preserved. For this reason, thin epoxy slices are currently used for research purposes in both macroscopic and microscopic studies. The protocol for the conventional epoxy technique (E12) follows the main steps of plastination—specimen preparation, dehydration, impregnation and curing/casting. Preparation begins with selection of the specimen, followed by freezing and slicing. Either fresh or fixed (embalmed) tissue is suitable for epoxy plastination, while slice thickness is kept between 1.5 and 3 mm. Impregnation mixture is made of epoxy E12 resin plus E1 hardener (100 ppw; 28 ppw). This mixture is reactive and temperature sensitive, and for this reason, total impregnation time under vacuum at room laboratory temperature should not last for more than 20–24 hr. Casting of impregnated slices is done in either flat chambers or by the so‐called sandwich method in either fresh mixture or the one used for impregnation. Curing is completed at 40°C to allow a complete polymerization of the epoxy‐mixture. After curing, slices can be photographed, scanned or used for anatomical study under screen negatoscope, magnification glass or fluorescent microscope. Based on epoxy sheet plastination, many anatomical papers have recent observations of and/or clarification of anatomical concepts in different areas of medical expertice.     

荷兰奶业产业链管理及质量控制

在第四届中国国际奶业展览会及高层论坛上,韩国、日本、德国、荷兰奶业交流专场吸引了众多中外奶业界同仁。国外专家关于本国奶牛养殖业、乳品加工业的精彩报告,使与会代表对各国的奶业发展现状和趋势有了全面而深入地了解。本刊编辑部,对各位国外专家的发言进行了整理,现分韩国篇、日本篇、德国篇、荷兰篇四个部分予以刊登,以飨读者,希望对中国建设现代奶业有所借鉴。     

Appearance of race Pfs:5 of spinach downy mildew fungus, Peronospora farinosa f. sp. spinaciae, in Japan

The races for the causal agent of spinach downy mildew Peronospora farinosa f. sp. spinaciae were identified by inoculation of race-differential cultivars. One isolate was identified as Pfs:5s and the others belonged to a new race. This is the first report of race Pfs:5 and another new race in Japan.     

Landscape-ecological mapping of the Netherlands

The Landscape-ecological Mapping of the Netherlands project (LMN project) started in 1983 with the aim of establishing a landscape-ecological database for use in developing and evaluating national land-use plans. The project, working with grid cells of 1 km², has four working objectives: a) development of mapping potential for basic landscape-ecological data, b) assessment of susceptibility to interventions, c) evaluation of significance for nature conservation and d) production of vulnerability maps, as a combination of susceptibility and significance. In addition to information on soil, groundwater, ecotopes, flora and fauna, the database also incorporates information on physiographical features and entire landscapes. The resulting database is a geographic information system (GIS). This article describes the second phase of the project (1985–1989), covering the Randstad area, and focusses on the methods and the applications potential of the database.     

RADIOGRAPHY OF THE EQUINE STOMACH

To obtain radiographic information concerning the equine stomach, a gastrographic contrast examination is required. This study describes this procedure in detail. A powerful radiographic unit, the tubehead linked to an image intensifier and suspended by an electromechanical overhead gantry system, is required. To obtain accurately positioned radiographs during the fluoroscopic examination, a cassette holder with a stationary grid is mounted at the entrance window of the image intensifier. The examination is performed in the unsedated standing horse after 24 hours of starvation, using a combination of survey radiography and fluoroscopic viewing after the inflation of air, followed by the administration of barium sulphate suspension by stomach tube. The gastrographic contrast examination is performed in three experimental animals and 23 abnormal horses. Pneumogastrophy appeared to be valuable to diagnose gastric tumors, to differentiate between gastric tumors and other masses in the cranial abdomen, and to visualize gastric parasites, even in large horses. The use of barium sulphate suspension does not result in an adequate double contrast of the stomach, but it may aid to diagnose esophagogastric or pyloric stenosis and gastric or duodenal ulcers.     

Antimicrobial properties of basil and its possible application in food packaging

Basil (Ocimum basilicum L.) is a popular culinary herb, and its essential oils have been used extensively for many years in food products, perfumery, and dental and oral products. Basil essential oils and their principal constituents were found to exhibit antimicrobial activity against a wide range of Gram-negative and Gram-positive bacteria, yeast, and mold. The present paper reviews primarily the topic of basil essential oils with regards to their chemical composition, their effect on microorganisms, the test methods for antimicrobial activity determination, and their possible future use in food preservation or as the active (antimicrobial), slow release, component of an active package.     

Rapid surface plasmon resonance-based inhibition assay of deoxynivalenol

Deoxynivalenol belongs to a group of highly toxic fungal metabolites produced by Fusarium species that may contaminate food and animal feed, mostly grains. Three different monoclonal mouse anti-deoxynivalenol antibodies were compared for the development of a surface plasmon resonance (SPR)-based immunoassay for the selective and quantitative determination of deoxynivalenol in naturally contaminated matrices. A conjugate of deoxynivalenol with the protein casein was prepared and immobilized on the sensor chip surface. An excess of antibody was added to each test solution before the measurement. The assay was based on the competition for antibody binding between the immobilized deoxynivalenol conjugate on the sensor and the free deoxynivalenol molecules in the test solution. The deoxynivalenol-casein sensor could be reused more than 500 times without significant loss of activity using 6 M guanidine chloride solution for regeneration. The cross-reactivity of the three antibodies in the SPR assay was tested with other trichothecene mycotoxins (3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, nivalenol, HT2-toxin, and T2-toxin). The only sample preparation was extraction with max 80 vol % acetonitrile and 10-fold dilution with the running buffer. The assay had an optimal range between 2.5 and 30 ng/mL deoxynivalenol in the test solution. Most results of the SPR-based assay were in agreement with liquid chromatography/tandem mass spectrometry measurements of naturally contaminated wheat samples.     

DNA hybridization assay for detection of nucleopolyhedrovirus in whitemarked tussock moth (Orgyia leucostigma) larvae

DNA dot‐blot hybridization assays utilizing a horseradish peroxidase‐labelled whole genomic DNA probe and enhanced chemiluminescence were conducted to quantify detection thresholds of nucleopolyhedrovirus (NPV) in whitemarked tussock moth (Orgyia leucostigma) larvae. The minimum detection thresholds for an aqueous suspension of occlusion bodies (OBs), OBs added to macerates of non‐infected larvae and OBs in macerates of diseased larvae were 7.8 × 10³, 7.8 × 10³, and 1.5 × 10³ OBs, respectively. Purified viral DNA was detected at a concentration of 1.6 × 10⁻¹ ng in a 20 µl volume. The presence of pre‐occluded viral nucleocapsids and DNA, inherent to infected larvae, improved the detection threshold five‐fold compared with OBs alone. Larval tissues did not block the detection system utilized, nor did they bind non‐specifically to the probe. Detection thresholds, upon sequential hybridization of the same membrane, on average deteriorated two‐fold between the first and second hybridization and an additional six‐fold between the second and third hybridization. NPV infection was detected two days post‐inoculation (pi) in about one‐third of the larvae examined and in almost all larvae three days pi. Microscopic analysis of stained larval smears missed NPV infection in almost all larvae two days pi and about two‐thirds of the larvae three days pi. Results from the two methods of analysis were not comparable until four days pi. The detection system utilized is a reliable, efficient and simple method for the early detection of NPV infection in large numbers of larvae and may be used for further studies quantifying the role of this baculovirus in the ecology of whitemarked tussock moth populations. © 2001 Society of Chemical Industry