The development of a medium supplemented with egg extract for the maintenance ofDrosophila cell lines

Summary A saline extract was prepared fromDrosophila eggs. When diluted to a concentration of 1% withDrosophila tissue culture medium, it did not support growth of cells from theDrosophila line D1 during the first few days of subculture as well as medium containing serum. When cells reached a stationary phase, however, the cell density in medium containing extract was greater than in medium containing serum. By altering the concentrations of the extract, and by adding bovine albumin, a medium was obtained in which D1 cells survived initial culturing, and which supported cell growth by day 4 as well as medium plus serum. The initial retardation of growth in medium containing egg extract might be due to the need of the cells to adapt to the new medium. At the present time fourDrosophila cell lines have been maintained in this medium for more than 16 passages. Preliminary experiments with primary embryonicDrosophila cells indicate that medium containing 2% extract and bovine albumin retards the differentiation of these cells. This work was supported by a grant from the Science Research Council of Great Britain.     

A simple method for displaying recalcitrant proteins on the surface of bacteriophage lambda

Bacteriophage lambda (λ) permits the display of many foreign peptides and proteins on the gpD major coat protein. However, some recombinant derivatives of gpD are incompatible with the assembly of stable phage particles. This presents a limitation to current λ display systems. Here we describe a novel, plasmid-based expression system in which gpD deficient λ lysogens can be co-complemented with both wild-type and recombinant forms of gpD. This dual expression system permits the generation of mosaic phage particles that contain otherwise recalcitrant recombinant gpD fusion proteins. Overall, this improved gpD display system is expected to permit the expression of a wide variety of peptides and proteins on the surface of bacteriophage λ and to facilitate the use of modified λ phage vectors in mammalian gene transfer applications.     

Distribution of Glutamate Transporter Subtypes During Human Brain Development

Abstract: In the mature brain, removal of glutamate from the synaptic cleft plays an important role in the maintenance of subtoxic levels of glutamate. This requirement is handled by a family of glutamate transporters, EAAT1, EAAT2, EAAT3, and EAAT4. Due to the involvement of glutamate also in neuronal development, it is believed that glutamate transport plays a role in developmental processes as well. Therefore, we have used immunohistochemical and immunoblot analysis to determine the distribution of the four glutamate transporters during human brain development using human pre- and postnatal brain tissue. Regional analysis showed that each transporter subtype has a unique distribution during development. EAAT2 was the most prominent glutamate transporter subtype and was highly enriched in cortex, basal ganglia, cerebellum, and thalamus in all ages examined. EAAT1 immunoreactivity was lower than that of EAAT2, with predominant localization in cortex, basal ganglia, hippocampus, and periventricular region. EAAT3 was located mainly in cortex, basal ganglia, and hippocampus, and EAAT4 was found only in cortex, hippocampus, and cerebellar cortex. The distinct regional distribution of various EAAT subtypes and also the transient expression of specific EAAT subtypes during development suggest multiple functional roles for glutamate transporters in the developing brain.     

Choline acetyltransferase in individual neurons of Aplysia californica

The activities of choline acetyltransferase in the various ganglia of the nervous system of Aplysia californica and in some of the individually identifiable neurons in these ganglia were measured. At least four of the neurons were characterized by an apparent absence of the enzyme. The neurons containing measurable amounts of the enzyme had reproducible levels from animal to animal. Individual neurons from the same animal were generally characterized by different levels of activity whether expressed on a cell or a protein basis. However, those pairs of neurons previously classified as ‘homologous’ because of their similar appearance, location and/or electrophysiological function, also contained the same total amounts of enzyme activity.     

High definition bronchoscopy: a randomized exploratory study of diagnostic value compared to standard white light bronchoscopy and autofluorescence bronchoscopy

Background

Videobronchoscopy is an essential diagnostic procedure for evaluation of the central airways and pivotal for the diagnosis and staging of lung cancer. Technological improvements have resulted in high definition (HD) images with advanced real time image enhancement techniques (i-scan).

Objectives

In this study we aimed to explore the sensitivity of HD+ i-scan bronchoscopy for detection of epithelial changes like vascular abnormalities and suspicious preinvasive lesions, and tumors.

Methods

In patients scheduled for a therapeutic or diagnostic procedure under general anesthesia videos of the bronchial tree were made using 5 videobronchoscopy modes in random order: normal white light videobronchoscopy (WLB), HD-bronchoscopy (HD), HD bronchoscopy with surface enhancement technique (i-scan1), HD with surface- and tone enhancement technique (i-scan2) and dual mode autofluorescence videobronchoscopy (AFB). The videos were scored in random order by two independent and blinded expert bronchoscopists.

Results

In 29 patients all videos were available for analysis. Vascular abnormalities were scored most frequently in HD + i-scan2 bronchoscopy (1.33 ± 0.29 abnormal or suspicious sites per patient) as compared to 0.12 ± 0.05 site for AFB (P = 0.003). Sites suspicious for preinvasive lesions were most frequently reported using AFB (0.74 ± 0.12 sites per patient) as compared to 0.17 ± 0.06 for both WLB and HD bronchoscopy (P = 0.003). Tumors were detected equally by all modalities. The preferred modality was HD bronchoscopy with i-scan (tone- plus surface and surface enhancement in respectively 38% and 35% of cases P = 0.006).

Conclusions

This study shows that high definition bronchoscopy with image enhancement technique may result in better detection of subtle vascular abnormalities in the airways. Since these abnormalities may be related to preneoplastic lesions and tumors this is of clinical relevance. Further investigations using this technique relating imaging to histology are warranted.     

The BioLexicon: a large-scale terminological resource for biomedical text mining

Background

Due to the rapidly expanding body of biomedical literature, biologists require increasingly sophisticated and efficient systems to help them to search for relevant information. Such systems should account for the multiple written variants used to represent biomedical concepts, and allow the user to search for specific pieces of knowledge (or events) involving these concepts, e.g., protein-protein interactions. Such functionality requires access to detailed information about words used in the biomedical literature. Existing databases and ontologies often have a specific focus and are oriented towards human use. Consequently, biological knowledge is dispersed amongst many resources, which often do not attempt to account for the large and frequently changing set of variants that appear in the literature. Additionally, such resources typically do not provide information about how terms relate to each other in texts to describe events.

Results

This article provides an overview of the design, construction and evaluation of a large-scale lexical and conceptual resource for the biomedical domain, the BioLexicon. The resource can be exploited by text mining tools at several levels, e.g., part-of-speech tagging, recognition of biomedical entities, and the extraction of events in which they are involved. As such, the BioLexicon must account for real usage of words in biomedical texts. In particular, the BioLexicon gathers together different types of terms from several existing data resources into a single, unified repository, and augments them with new term variants automatically extracted from biomedical literature. Extraction of events is facilitated through the inclusion of biologically pertinent verbs (around which events are typically organized) together with information about typical patterns of grammatical and semantic behaviour, which are acquired from domain-specific texts. In order to foster interoperability, the BioLexicon is modelled using the Lexical Markup Framework, an ISO standard.

Conclusions

The BioLexicon contains over 2.2 M lexical entries and over 1.8 M terminological variants, as well as over 3.3 M semantic relations, including over 2 M synonymy relations. Its exploitation can benefit both application developers and users. We demonstrate some such benefits by describing integration of the resource into a number of different tools, and evaluating improvements in performance that this can bring.