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Biomedical subjects

E N Robinson

Publications and source records attributed to E N Robinson.

At least 19 recordsLinked to original sources

Gastrointestinal handling and metabolic disposal of 13C-labelled tripalmitin during rehabilitation from childhood malnutrition.

We investigated the gastrointestinal handling and post-absorptive metabolic handling of [1,1,1-13C]tripalmitin and [1-13C]glycocholate during recovery from severe childhood malnutrition. Eight children were studied on three occasions: at admission (phase 1), during rapid catch-up growth (phase 2) and when weight-for-height had reached 90 % of the reference (phase 3). Breath samples were obtained over a 24 h period and stools were collected over 3 d following the administration of each tracer. At admission, the lipid content of stool expressed as a percentage of ingested lipid was 6 (range 0.7-28.9) but less variation was shown between children at phase 2 (3.3 (range 0.9-4.1)) and phase 3 (1.4 (range 0.4-2.5)). The excretion of 13C in stool varied markedly between children at admission (11.1 (sd 5.4) % administered dose) and during rehabilitation (phase 2, 15.4 (sd 16.5) % administered dose; phase 3, 6.2 (sd 10.2) % administered dose). About 5 % of the absorbed label was recovered on breath at each stage (% absorbed dose; phase 1, 5.1 (sd 6.0); phase 2, 5.2 (sd 3.1); phase 3, 6.4 (sd 6.6)). None of the children exhibited significant bile salt malabsorption as a consequence of small intestinal overgrowth. Of the 13C measured in stool, more label was recovered in fatty acids than triacylglycerols during each of the three phases and this was interpreted to reflect a failure to absorb the products of digestion. The results show that not all the children had problems associated with the digestion and absorption of 13C-labelled tripalmitin in severe malnutrition and during recovery, which was not reflected in gross lipid balance across the gastrointestinal tract. Absorbed lipid was more likely to be deposited as adipose tissue than to satisfy the immediate needs for energy.

Adolescent↗

Student and faculty performance in clinical simulations with access to a searchable information resource.

In this study we explore how students' use of an easily accessible and searchable database affects their performance in clinical simulations. We do this by comparing performance of students with and without database access and compare these to a sample of faculty members. The literature supports the fact that interactive information resources can augment a clinician's problem solving ability in small clinical vignettes. We have taken the INQUIRER bacteriological database, containing detailed information on 63 medically important bacteria in 33 structured fields, and incorporated it into a computer-based clinical simulation. Subjects worked through the case-based clinical simulations with some having access to the INQUIRER information resource. Performance metrics were based on correct determination of the etiologic agent in the simulation and crosstabulated with student access of the information resource; more specifically it was determined whether the student displayed the database record describing the etiologic agent. Chi-square tests show statistical significance for this relationship (chi 2 = 3.922; p = 0.048). Results support the idea that students with database access in a clinical simulation environment can perform at a higher level than their counterparts who lack access to such information, reflecting favorably on the use of information resources in training environments.

Bacteriology↗

Clinical event management using push technology--implementation and evaluation at two health care centers.

For two years, beginning in 1995, we developed and implemented a novel method for delivering patient information directly to clinicians. Using rules based logic to scan data bound for an electronic medical record, messages were automatically written that alert care providers to important patient information. These messages were transmitted electronically to either existing email accounts or to wide-screen pagers, or to both. This system now is operational at two medical centers. We describe the model and methods that led to its successful implementation and compare it to other ways of delivering patient information.

Attitude to Computers↗

Relational database design: evaluation of the recognition, isolation and treatment of hospitalized patients with tuberculosis.

Hospitals have been charged with the the evaluation of their abilities to identify, diagnose, isolate and treat individuals with active tuberculosis. This evaluation can be facilitated by a properly designed relational database. Using Entity Relationship diagrams, a relational data model, and the process of normalization, a database was designed that will contain the information gathered in prospective surveillance of tuberculosis in a community hospital. Although the authors' intent is to implement the design using a personal computer and a commercially available relational database management tool (Microsoft Access), the design is independent of the management tool and can be applied to other systems.

Database Management Systems↗

Arguments against the chemoprophylactic use of zidovudine following occupational exposure to the human immunodeficiency virus.

Following the paradigm of the hospitals of the National Institutes of Health and the University of California at San Francisco, many medical facilities have instituted a policy of administering zidovudine to health care workers after exposure to blood potentially contaminated with the human immunodeficiency virus. There is no clinical evidence proving the efficacy of such chemoprophylaxis. Toxic effects associated with zidovudine are usual and at times severe. The institutional administration of zidovudine to anyone other than individuals infected with the human immunodeficiency virus should be discontinued except under the auspices of a randomized, placebo-controlled trial.

Didanosine↗

Staphylococcal meningitis can present as an abscess of a single lateral ventricle.

Ventricular obstruction and hydrocephalus are recognized complications of neurosurgical procedures and meningitis that has been previously treated. The confinement of bacterial meningitis solely to a lateral ventricle in an otherwise healthy individual, however, is rare. I describe a case in which a ventricular abscess occurred as the presenting manifestation of staphylococcal meningitis in a man who had no history of head trauma or neurosurgery.

Adult↗

Probing the surface of Neisseria gonorrhoeae: immunoelectron microscopic studies to localize cyanogen bromide fragment 2 in gonococcal pili.

Common epitopes accessible to antibody on purified macromolecules or structurally altered gonococci may not be accessible to antibody when those macromolecules are in their native state on the surface of intact organisms. To determine the immunologic accessibility of cyanogen bromide fragment 2 (CNBr2), a portion of the gonococcal pilin molecule that is common to all gonococcal strains on the surface of viable gonococci, probes composed of specific CNBr2 antibodies linked to gold spheres were manufactured. When whole piliated gonococci were exposed to these anti-CNBr2 immunological probes and examined using transmission electron microscopy, no significant marketing of native pili was evident. These probes, however, detected CNBr2 in purified form. The epitopes encompassed within the CNBr2 portion of pili appear to be inaccessible to anti-CNBr2 probes within native gonococcal pili.

Antibodies, Bacterial↗

Immunoelectron microscopic localization of outer membrane proteins II on the surface of Neisseria gonorrhoeae.

To determine the ultrastructural distribution and immunological accessibility of proteins II (P.IIs) on the surfaces of whole gonococci, anti-P.II gold probes were developed and used in electron microscopic studies of viable P.II-expressing variants of Neisseria gonorrhoeae FA1090. Anti-P.II probes clearly marked the surfaces of organisms and their associated outer membrane blebs. The surface-exposed portion of P.II is antigenically variable. With the use of two different sizes of gold probes, it was demonstrated that individual gonococcal cells can express more than one antigenic type of P.II simultaneously.

Antibodies, Monoclonal↗

Microbial invasion: a covert activity?

In contrast to nonpathogenic microorganisms that exist happily in biofilms on various organic and inorganic surfaces, many pathogenic microbes have the additional ability to invade host tissues by inducing their own endocytosis and transport across normally protective barriers. This phenomenon, designated "parasite-directed endocytosis," has been observed with a variety of surfaces (intestinal, genital, nasopharyngeal, and tracheal epithelium) as well as in endothelial cells. The mechanisms involved in invasion may involve a single factor as described for some species of Yersinia, or may require multiple factors as observed in Shigellae. For the majority of pathogens, the molecular mechanisms of invasion are not well understood (e.g., Neisseria gonorrhoeae). Because parasite-directed endocytosis is reminiscent of receptor-mediated endocytosis, it is quite possible that some pathogens engage in biologic mimicry by producing a molecule that resembles a natural host ligand, for which there is a host cell receptor. Such a masquerade may allow some microbes to enter the host's inner sanctum covertly in a manner analogous to the Trojan horse, rather than overtly by destroying the mucosa and entering host tissues directly. Whereas this hypothesis is speculative at present, bacteria that produce molecules resembling insulin, calmodulin, and chorionic gonadotropin have been described.

Animals↗

Analyses of the immunoaccessibility of H8 antigen and the functionality of H8 specific monoclonal antibody 10.

The immunoaccessibility of the H8 antigen was examined as was the functionality of H8 specific monoclonal antibody (McAb 10). Immunoaccessibility of H8 varied among individual gonococci grown in vitro; the overall degree of variability was strain dependent. The H8 antigen was detected on the surface of most but not all gonococci found in urine sediment from an infected volunteer. The H8 specific McAb 10 was not bactericidal for strains of serum resistant gonococci; in the serum sensitive strain, an increase of approximately .5 logs above the bactericidal activity of antibody depleted normal human serum was observed. It is possible that the apparent paradox of the common, immunogenic, antigenic surface constituent H8 may be resolved in part by variation in immunoaccessibility within and among gonococcal strains.

Antibodies, Bacterial↗

The frequency of expression of pyelonephritis-associated pili is under regulatory control.

The Escherichia coli urinary tract isolate C1212 contains two pyelonephritis-associated pili (pap) DNA sequences designated here as pap-17 and pap-21. Each of these pap sequences encodes antigenically-distinct pilin monomers, pilin-17 and pilin-21, respectively. Most individual strain C1212 cells isolated from a single bacterial colony expressed pilin-21. Only a small fraction (5%) of strain C1212 cells expressed pilin-17. Most of the latter population simultaneously expressed pilin-21, but a low percentage of cells expressed pili composed of pilin-17 alone. In contrast, almost every E. coli K-12 cell containing multicopy pap-17 expressed pilin-17 at the cell surface. These results indicated that the regulation of pilin-17 expression observed for strain C1212 was lost when pap-17 was in the multicopy state. Transfer of pap-17 to a single copy vector resulted in a pilin-17 expression frequency lower than strain C1212 (1%). Using E. coli K-12 containing single copy pap-17, we found that the frequency of pilin-17 expression increased about 15-fold when pap-21 was present in multiple copies in trans. Subcloning of pap-21 showed that a 2.2 kilobase-pair DNA sequence adjacent to, but not including, the pilin-21 structural gene was sufficient for activation of pilin-17 expression.

Bacterial Outer Membrane Proteins↗

Probing the surface of Neisseria gonorrhoeae: simultaneous localization of protein I and H.8 antigens.

Gonococcal outer membrane protein I and the neisserial antigen H.8 are being investigated for inclusion in a gonococcal vaccine. To determine the distribution of immunoaccessible protein I and H.8 molecules on the surface of viable gonococci and to approximate the accessibility of these antigens to vaccine-elicited antibodies, immunologic probes composed of protein I- and H.8-specific antibodies linked to gold spheres were developed. When whole gonococci were exposed to the protein I and H.8 immunologic probes and examined by transmission electron microscopy, gold spheres clearly marked the surface of some of the gonococci, but not the surface of other gonococci from the same culture. The immunologic accessibility of gonococcal protein I or neisserial H.8 varied among gonococci. This diversity may affect the efficacy of a vaccine composed of these surface antigens.

Antibodies, Monoclonal↗

Ultrastructural localization of L and NS enzyme subunits on vesicular stomatitis virus RNPs using gold sphere-staphylococcal protein A-monospecific IgG conjugates.

Colloidal gold spheres were coated with staphylococcal protein A and were used to determine the location of NS and L proteins on vesicular stomatitis virus (VSV) ribonucleoprotein (RNP) complexes using monospecific anti-NS and anti-L IgG preparations. Conjugates using either anti-NS or anti-L demonstrated that these enzyme subunits were uniformly distributed along the entire length of the RNP complex. Under saturating conditions of IgG concentrations, it was observed that there were at least 60-70 molecules of NS protein and 30-35 molecules of L protein labeled per RNP complex.

HeLa Cells↗

Extrinsic factors that put patients at risk of acquiring central nervous system infections.

Although many host defenses, including physical barriers, phagocytic cells, and humoral elements, normally protect the central nervous system from microbial pathogens, a variety of extrinsic factors may compromise these defenses and put patients at risk of acquiring central nervous system infection. These risk factors include: (1) communication of the cerebrospinal fluid space with integumentary surfaces; (2) communication of the cerebrospinal fluid space with other body spaces through shunts; (3) suppurative foci contiguous to the central nervous system; (4) hematogenous spread of infectious agents; (5) new acquisition of infectious agents with a propensity for causing central nervous system infection; and (6) administration of certain antimicrobial or immunosuppressive drugs. Recognition that these factors are present and therefore that the patient is at risk allows monitoring for and prompt response to signs and symptoms of central nervous system infection.

Bacterial Infections↗

Ultrastructural localization of specific gonococcal macromolecules with antibody-gold sphere immunological probes.

In an effort to determine the ultrastructural location of specific macromolecules on the surface of intact microorganisms and in experimentally infected tissues, a new method of rapidly conjugating antibodies to gold spheres via a staphylococcal protein A intermediary has been developed. This new technique provides the excellent density of marking and versatility of sphere size provided by existing gold methods, but decreases preparation time, decreases the chance of bacterial contamination of antibody reagents, and increases specificity of marking. Staphylococcal protein A-coated gold spheres were conjugated with antibodies from rabbits immunized with purified gonococcal pili. The resulting gold-antibody conjugates allowed demonstration of antibody binding to pilus structures of the same gonococcal strain whose pili were used to raise the antibody and demonstration of the lack of antibody recognition of pilus structures on two other gonococcal strains. The failure of gold spheres to attach to isogenic nonpiliated clones of the homologous gonococcus indicated the absence of pilus antigens on the surface of these organisms. The use of a double label--small gold spheres conjugated to anti-pilus antibody and larger gold spheres conjugated to anti-protein I antibody--allowed the simultaneous localization of two gonococcal antigens.

Antibodies, Bacterial↗

Pneumococcal endometritis and neonatal sepsis.

A recent case of postpartum maternal endometritis and neonatal sepsis due to Streptococcus pneumoniae prompted this report and a review of previous citations. Although this rare presentation of pneumococcal infection is potentially fatal to both mother and child, early empiric antibiotic coverage for the most frequent etiologic agents of this syndrome, group B streptococci, was and is adequate for systemic pneumococcal infections.

Endometritis↗