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At least 883 records · Page 49Linked to original sources

Experimental corticosteroid ocular hypertension in the rabbit.

Weekly subconjunctival injections of 4mg repository betamethasone, repeated over three weeks, produced a sustained increase of intraocular pressure (IOP) in 96% of the treated rabbits. Treatment was generally well tolerated and important systemic toxic effects were present only in a few animals. The ocular hypertension so obtained was constant, well reproducible and sensitive to antiglaucoma drugs. The authors believe they have developed an animal model which is very suitable for testing the pressure-lowering effect of drugs and for other studies on ocular hypertension and glaucoma.

Animals↗

IgG anti-tetanus toxoid antibody synthesis by human bone marrow. I. Two distinct populations of marrow B cells and functional differences between marrow and peripheral blood B cells.

This investigation uses a system for inducing and detecting anti-tetanus toxoid antibody (anti-TT) synthesis to study specific antibody (Ab) synthesis by bone marrow mononuclear cells (MC). We measured the amounts of anti-TT secreted and the number of B cells secreting antibody (Ab). The ELISA plaque detects single B cells secreting specific Ab. The results show that (1) spontaneous anti-TT secretion by MC is higher than spontaneous anti-TT secretion by peripheral blood lymphocytes (PBL) using an ELISA plaque (P less than 0.01); (2) spontaneous anti-TT production by MC correlated with the serum anti-TT titers as measured by an ELISA (r = 0.75, P = 0.005); (3) two types of marrow B cells were identified--one that spontaneously secretes anti-TT and another that produces anti-TT after TT-stimulation; (4) the frequency of anti-TT-secreting B cells is higher in MC than in PBL; (5) the amount of Ab secreted per marrow B cell is not different from that secreted by a peripheral B cell; and (6) marrow B cells could be induced to produce anti-TT in vitro up to 10 months without added cytokines. These results show that bone marrow is a major repository for differentiated B cells that spontaneously produce Abs to maintain circulating Abs titers and for memory B cells that can be induced to produce specific Ab.

Antigens, Differentiation, T-Lymphocyte↗

Free D- and L-amino acids in ventricular cerebrospinal fluid from Alzheimer and normal subjects.

Free D-Ser, D-Asp and total D-amino acids were significantly higher (p < 0.05) in Alzheimer (AD) ventricular CSF than in normal CSF. There was no significant difference in the total L-amino acids between AD and normal CSF, but L-Gln and L-His were significantly higher (p < 0.05) in AD-CSF. The higher concentrations of these D- and L-amino acids in AD ventricular CSF could reflect the degenerative process that occurs in Alzheimer's brain since ventricular CSF is the repository of amino acids from the brain.

Alzheimer Disease↗

Comparison of membrane ATPases from extreme halophiles isolated from ancient salt deposits.

Halophilic microorganisms were isolated from Triassic and Permian salt deposits. Two were rods and grew as red colonies; another was a coccus and produced pink colonies. The rods lysed in solutions that lacked added sodium chloride. Growth of all isolates was inhibited by aphidicolin and their bulk proteins were acidic as judged from isoelectric focusing. Therefore, these organisms were tentatively identified as extreme halophiles. Whole cell proteins patterns of the isolates following gel electrophoresis were distinct and differed from those of representative type strains of halophilic bacteria. The membrane ATPases from the rods were similar to the enzyme from Halobacterium saccharovorum with respect to subunit composition, enzymatic properties and immunological cross-reaction, but differed slightly in amino acid composition. If the age of the microbial isolated is similar to that of the salt deposits, they can be considered repositories of molecular information of great evolutionary interest.

Adenosine Triphosphatases↗

Influenza: global surveillance for epidemic and pandemic variants.

Influenza viruses, unlike other viruses for which vaccines have been developed, undergo rapid and unpredictable antigenic variation in the hemagglutinin (HA), the surface glycoprotein primarily responsible for eliciting neutralizing antibodies during infection. Because of this antigenic variability and its consequences, the World Health Organization (WHO) in 1947 established an international network of collaborating laboratories to monitor the emergence and spread of new epidemic and pandemic strains of influenza. This network now includes three international WHO collaborating centers and over 100 WHO national collaborating laboratories. The primary purpose of this network is to detect, through laboratory surveillance, the emergence and spread of antigenic variants of influenza that may signal a need to update the formulation of the influenza vaccine. This laboratory surveillance network has provided the strains needed to update the vaccine as well as a repository of influenza viruses useful for studying the antigenic and genetic evolution of this virus. Knowledge gained from molecular studies on the evolution of drift variants and on the emergence of pandemic strains has made influenza a useful model for understanding the potential threat of other emerging or reemerging microbial diseases.

Antigenic Variation↗

Histamine and mucosal mast cells in gluten enteropathy.

Coeliac disease is a malabsorptive disorder caused by intolerance to gluten and is characterized by a remodelling of the intestinal mucosa including villus atrophy, crypt hyperplasia and net increase of mucosal volume. Changes of the number of mucosal mast cells (MMCs) in coeliac mucosa has recently been reported, suggesting that the mast cell activity could have a pathogenetic role in gluten enteropathy. MMCs located solely in the lamina propria are the main repository for small-gut mucosal histamine. A consecutive prospective study was designed to study the histamine content, MMC numbers, and the relative volume of lamina propria in intestinal biopsies from adult patients suffering from unexplained diarrhea and/or malnutrition. Histamine was measured by a HPLC-method, the number of MMC was counted after long toluidine-blue staining, and the relative volumes of lamina propria and epithelium were estimated morphometrically. The findings were correlated to the histopathological appearance of the mucosa. As compared to controls the histamine content increased by 80% and MMC numbers by about 60% in the coeliac mucosa. There was also a correlation between MMC numbers and histamine content for both normal and coeliac mucosae (r = 0.81). The morphometric estimation of the relative volumes of epithelium and lamina propria revealed that the lamina-propria compartment was increased by approximately 40% in coeliac mucosa. Taking the changes in compartmental volumes of the remodelled coeliac mucosa into account, our results suggest that the histamine content and MMC population were significantly increased. MMC and MMC-associated histamine may therefore be involved in the pathogenesis of gluten enteropathy.

Celiac Disease↗

An RNA replisome as the ancestor of the ribosome.

The ribosome is proposed to have evolved from an earlier RNA-replisome, which synthesized RNA. Ancestral tRNA molecules originally were loaded with trinucleotide sequences and donated them to growing RNA chains. The enzymatic addition of the C-C-A trinucleotide to presentday transfer RNA molecules is a carryover from this function. The strategies of reading RNA sequences by triplet codons and of housing information genetically in special repository molecules predates the origin of protein and DNA. These latter two polymers arose together at the time when the RNA replisome was converted to a ribosome.

Base Sequence↗

A real-time library of medicine for practicing physicians.

An on-line, practice-oriented library system now exists in prototype form which can act as a central repository of medical information. The source data are gathered by the residents at Shands Teaching Hospital and Clinics at the University of Florida as part of their rotation through clinical pathology. The information is continually updated and reviewed every 3 months by new residents and area specialists. Plans are under way to make this pool of information accessible to all levels of the health care team in an instantaneously addressable fashion via CRT (cathode ray tube). After many months of resource development, we have major sections of an on-line dictionary of clinical and surgical pathology and expect to expand this in the future to include a medical problem-oriented indexing system, a disease-oriented library, and a page-associated file of reference.

Computers↗

Mass screening for colorectal cancer.

A voluntary community colorectal cancer screening project to detect occult blood in the stool of asymptomatic individuals was undertaken; 49,353 Hemoccult II kits were distributed. A total of 23,674 completed kits were returned to a central repository and processed (compliance rate, 48 percent); 851 participants had positive results (3.6 percent). Of the 640 who underwent further medical evaluation, 299 participants (46.7 percent) who had adequate follow-up had no evidence of disease. Diverse disease entities were detected in 341 participants, which was 1.4 percent of those enrolled. Forty-one patients (0.17 percent) showed significant findings that included 29 cancers (0.12 percent) and 12 (0.05 percent) noninvasive malignant polyps. Of the cancers, there were 27 colorectal, one non-Hodgkin's lymphoma, and one carcinoma of the vocal cord. In addition, 107 patients (0.45 percent) had benign polyps and 193 patients (0.82 percent) had various diseases of the gastrointestinal tract and other medical conditions. The cost of the program was modest and the results conformed to those found in previous screening surveys. The heightened public awareness of testing for colorectal disease and the detection of early lesions justifies the guaiac test screening program for mass survey.

Adult↗

Patenting of hybridomas and genetically engineered microorganisms.

Many new technologies arrived at through basic research have practical applications. Two recent breakthroughs in microbiology, recombinant DNA techniques and hybridoma techniques, will permit designing cells for specific practical purposes resulting in new products or functions of commercial significance. The unique cell or its usefulness, or both, may satisfy the requirements of a patentable invention, i.e. an inventive act having utility and novelty. Ownership of such patents permits recovery of expenses incurred in the invention process and investment for all concerned in additional research. An integral part of the patenting process is submission of the new cell to an official repository, an outstanding example of which is The American Type Culture Collection.

DNA, Recombinant↗

Can radiologic images be incorporated into the electronic patient record?

As radiology makes advances toward filmlessness, all of medicine is headed, just as rapidly, toward paperless transmission of patient information. While there are obvious advantages to this electronic approach, and several standards to conform to for the transmission of textual (Health Level 7 [HL-7]) and image (Digital Imaging and Communications in Medicine [DICOM]) data, it is the integration of these two data sets that is clinically essential and yet poorly defined. This report defines an approach for, and the successful implementation of, the integration of radiologic image data with textual data contained within the electronic patient record (EPR) through the use of standard internet protocols. Incorporation of medical images in the EPR has proven to be critical to the successful deployment of picture archiving and communications systems (PACS) and the reduction of film consumption at Massachusetts General Hospital (MGH). Since the installation of the first internet-based Image Data Repository (IDR) at MGH in 1995, the system has adequately served to meet the needs of clinical requests by both radiology-only browser users and users of the EPR. It has drastically reduced the need for film and provided concurrent display of images and text throughout the institution and beyond.

Computer Systems↗

Electronic teaching files: seven-year experience using a commercial picture archiving and communication system.

With the advent of electronic imaging and the internet, the ability to create, search, access, and archive digital imaging teaching files has dramatically improved. Despite the fact that a picture archival and communication system (PACS) has the potential to greatly simplify the creation of, archival, and access to a department or multifacility teaching file, this potential has not yet been satisfactorily realized in our own and most other PACS installations. Several limitations of the teaching file tools within our PACS have become apparent over time. These have, at our facility, resulted in a substantially reduced role of the teaching file tools for conferences, daily teaching, and research purposes. With the PACS at our institution, academic folders can only be created by the systems engineer, which often serves as an impediment to the teaching process. Once these folders are created, multiple steps are required to identify the appropriate folders, and subsequently save images. Difficulties exist for those attempting to search for the teaching file images. Without pre-existing knowledge of the folder name and contents, it is difficult to query the system for specific images. This is due to the fact that there is currently no fully satisfactory mechanism for categorizing, indexing, and searching cases using the PACS. There is currently no easy mechanism to save teaching, research, or clinical files onto a CD or other removable media or to automatically strip demographic or other patient information from the images. PACS vendors should provide much more sophisticated tools to create and annotate teaching file images in an easy to use but standard format (possibly Radiological Society of North America's Medical Image Resource Center [MIRC] format) that could be exchanged with other sites and other vendors' PAC systems. The privilege to create teaching or conference files should be given to the individual radiologists, technologists, and other users, and an audit should be kept of who has created these files, as well as keep track of who has accessed the files. Vendors should maintain a local PACS library of image quality phantoms, normal variants, and interesting cases and should have the capability of accessing central image repositories such as the RSNA's MIRC images. Commercial PAC systems should utilize a standard lexicon to facilitate the creation and categorization of images, as well as to facilitate sharing of images and related text with other sites. This should be combined with a very easy to use mechanism to write images and related text when appropriate onto removable media (while maintaining a high level of security and confidentiality) to make it easier to share images for teaching, research, or clinical purposes.

Computer-Assisted Instruction↗

The National Institutes of Health Clinical Center Digital Imaging Network, Picture Archival and Communication System, and Radiology Information System.

In this work, we describe the digital imaging network (DIN), picture archival and communication system (PACS), and radiology information system (RIS) currently being implemented at the Clinical Center, National Institutes of Health (NIH). These systems are presently in clinical operation. The DIN is a redundant meshed network designed to address gigabit density and expected high bandwidth requirements for image transfer and server aggregation. The PACS projected workload is 5.0 TB of new imaging data per year. Its architecture consists of a central, high-throughput Digital Imaging and Communications in Medicine (DICOM) data repository and distributed redundant array of inexpensive disks (RAID) servers employing fiber-channel technology for immediate delivery of imaging data. On demand distribution of images and reports to clinicians and researchers is accomplished via a clustered web server. The RIS follows a client-server model and provides tools to order exams, schedule resources, retrieve and review results, and generate management reports. The RIS-hospital information system (HIS) interfaces include admissions, discharges, and transfers (ATDs)/demographics, orders, appointment notifications, doctors update, and results.

Hospital Information Systems↗

Online analysis of europium and gadolinium species complexed or uncomplexed with humic acid by capillary electrophoresis-inductively coupled plasma mass spectrometry.

Detailed information on the geochemical behavior of radioactive and toxic metal ions under environmental conditions (in geological matrices and aquifer systems) is needed in order to assess the long-term safety of waste repositories. This includes knowledge of the mechanisms of relevant geochemical reactions, as well as associated thermodynamic and kinetic data. Several previous studies have shown that humic acid can play an important role in the immobilization or mobilization of metal ions due to complexation and colloid formation. In our project we investigate the complexation behavior of (purified Aldrich) humic acid and its influence on the migration of the lanthanides europium and gadolinium (homologs of the actinides americium and curium) in the ternary system consisting of these heavy metals, humic acid and kaolinite (KGa-1b) under almost natural conditions. Capillary electrophoresis (CE, Beckman Coulter P/ACE MDQ), with its excellent separation performance, was hyphenated with a homemade interface to inductively coupled plasma mass spectrometry (ICP-MS, VG Elemental PlasmaQuad 3) giving a system that is highly sensitive to the rare-earth element species of europium and gadolinium with humic acid. The humic acid used was also halogenated with iodine, which acted as an ICP-MS marker. To couple CE to ICP-MS, a fused silica CE capillary was flexibly fitted into a MicroMist 50 mul nebulizer with a Cinnabar cyclonic spray chamber in the external homemade interface. The chamber was chilled to a temperature of 4 degrees C to optimize the sensitivity. 200 ppb of cesium were added to the CE separation buffer so that the capillary flow could be observed. A make-up fluid including 4 ppb Ho as an internal standard was combined with the flow from the capillary within the interface in order to get a fluid throughput high enough to maintain continuous nebulization. Very low detection limits were achieved: 125 ppt for 153Eu and 250 ppt for 158Gd. Using this optimized CE-ICP-MS coupling system it was possible to quantify metal concentrations from the detection limit up to approximately 1 ppm (the linear range). This set-up was used to separate metal/humic acid-species in a 100 mM acetic acid/10 mM acetate buffer system. Using humic acid as the complexing ligand, uncomplexed metal ion species could be separated from metal-humate complexes on a time-resolved scale.

Journal Article↗

Aggravation of licensing procedures by doubtful thermodynamic data.

Environmental prognosis by geochemical modelling is a scientific approach to several open questions of general public interest. Two prominent fields where geochemical modelling holds an important share are the remediation of contaminated former uranium mining areas and safety assessment of radioactive waste repositories in the geosphere. In both fields, application of geochemical modelling is stipulated by public authorities. The enormous complexity of models that can be handled by computers rises the awareness on the meaningfulness of a modelling result and demands for provision of an estimate of the dependability of a calculation output by the computers. It is obvious that bias, over- and underestimation of uncertainty in input data reduces the relevance of the calculation output. Chemistry contributes important data to geochemical modelling, both from field analysis and in the fundamental physico-chemical quantities enclosed into the thermodynamic data base. Some examples will be given where progress in quality assessment of chemical data may further the predictive power of geochemical modelling.

Journal Article↗

Comparability of thermodynamic data--a metrological point of view.

In order to compare and to interpret chemical measurements, compliance with general rules of metrology is compulsory. Such rules are the more important the more the chemical measurements are applied under circumstances where material assets and goods or immaterial values like health may be affected. Metrology of chemical measurements attempts to define rules for achieving comparability and for guaranteeing quality of analytical data. Thermodynamic data are commonly derived from a set of analytical measurements. Comparability among thermodynamic data is an important issue especially for those data to be applied in politically sensitive issues of environmental prognosis, long-term safety assessment of nuclear waste repositories in deep geological formations and assessment of environmental impact of technical intervention in the geosphere. Taking the data evaluation step in the traceability chain of thermodynamic data as an example, the existing thermodynamic data is shown to be affected by deficiencies in comparability and quality that may severely limit its dependability in environmental prognosis. The need for a metrologically acceptable approach is demonstrated. Statistical concepts improving a reliable assignment of meaningful measurement uncertainty to a thermodynamic datum are presented. Unresolved issues, i.e. measurement uncertainty of a pH measurement, hampering the construction of a traceability chain are outlined.

Journal Article↗

Tidal creek and salt marsh sediments in South Carolina coastal estuaries: II. Distribution of organic contaminants.

Twenty-eight tidal creeks along the South Carolina coast were sampled during the summer of 1995 to determine the levels of sediment contamination including organic chemicals (i.e., polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and DDT and its metabolites) associated with different types and varying levels of watershed development (i.e., industrial/urban, suburban, forested, and salt marsh). Organic analysis utilized high-performance liquid chromatography (HPLC) with fluorescence detection and capillary gas chromatography-ion trap mass spectrometry (GC-ITMS) for PAHs, and gas chromatography with electron capture detection (GC-ECD) for pesticides and PCBs. Results indicated that creeks with industrial/urban watersheds had significantly higher concentrations of PAHs, PCBs, and DDT compared with creeks with suburban and forested (reference) watersheds. The suburban watershed class of creeks had concentrations of half the PAH analytes and the total PCBs which exceeded the concentrations found in the forested watershed class of creeks. The spatial distribution of organic contaminants was evaluated in four of these tidal creek-salt marsh systems representing urban/industrial, suburban, and forested watersheds, from the creek channel to the adjacent uplands. The distribution of organic contaminants within each representative creek was not concordant with the total organic carbon or the clay content of the sediment. The representative industrial/urban creek-marsh system, Diesel Creek, had the highest concentration of PAHs in the creek channel and the highest concentration of PCBs and DDT on the marsh surface, primarily in the upper portion of the system. The representative suburban creek-marsh system, Shem Creek, had elevated levels of both PAHs and PCBs throughout the entire system. This system also had one site with a total PAH concentration of 324,000 ppb and a total DDT concentration that was 20-100 times higher than the other sites. One of the representative forested creek-marsh systems, Rathall Creek, had low levels of the three organic contaminants except for one sampling site that had PAH concentrations a factor of 10 higher than the other sites. The other representative forested creek-marsh system, Long Creek, had low levels of PAHs and PCBs, but elevated levels of DDT were observed, particularly in the upper portion on the marsh surface. The results of this study suggest that (1) anthropogenic alteration of the land cover in the watersheds of tidal creek-salt marsh systems may increase the organic contaminant loadings in the sediment, and (2) tidal creek-salt marsh sediments, particularly in the creek channel, are repositories and potentially conduits of organic contaminants from the upland environment to the deeper estuarine areas.http://link.springer-ny. com/link/service/journals/00244/bibs/37n4p458.html</++ +HEA

Chromatography, Gas↗

Petroleum hydrocarbon bioremediation: sampling and analytical techniques, in situ treatments and commercial microorganisms currently used.

The sampling and analytical methods, along with available microorganisms, used for in situ hydrocarbon bioremediation are reviewed. Each treatment method is briefly described and its advantages and limitations pertaining to potential applications are evaluated. Bioremediation provides cost-effective, contaminant- and substrate-specific treatments equally successful in reducing the concentrations of single compounds or mixtures of biodegradable materials. In situ treatments rarely yield undesirable byproducts, but precautions and preliminary baseline tests are always recommended. Sampling methods should adhere to good laboratory and field practices and usually do not require highly trained personnel. Analytical methods vary in sensitivity, cost, duration of sample analysis and personnel training required. Voucher specimens of bacterial strains used in bioremediation exist in various repositories (e.g. ATCC, DSM, etc.) or are commercially available, and are usually covered by patent rights. Each one of these strains may yield spectacular results in vitro for specific target compounds. However, the overall success of such strains in treating a wide range of contaminants in situ remains limited. The reintroduction of indigenous microorganisms isolated from the contaminated site after culturing seems to be a highly effective bioremediation method, especially when microorganism growth is supplemented by oxygen and fertilizers.

Bacteria↗