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.

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.

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.

The college student, the dentist, and the North Carolina senator: risk analysis and risk management of HIV transmission from health care worker to patient.

The risk of acquiring human immunodeficiency virus (HIV) infection from a health care worker is 2,000 times less than that of dying from a car accident. It is 700 times less probable than perishing from being struck by lightning or suffering a fatal fall. Despite the rarity of this occurrence, reduction of the risk of health-care-worker-to-patient HIV transmission in the workplace has been the focus of congressional, federal, state, and local agencies. If all HIV transmission from health care workers to patients were prevented using current guidelines and legislation, the epidemic of AIDS would be reduced by 0.0006%. Current efforts to prevent HIV transmission from health care workers to patients are the result of incomplete risk analysis and management. In a society of limiting resources and of cherished freedoms, sanctions imposed on health care workers to prevent HIV transmission to patients may benefit no one.

Trichuris trichiura elicits a secretory response in infected children - abstract

Trichuriasis occurs in children infected with the tropical helminth Trichuris trichiura. The children usually present with various clinical symptoms such as diarrhoea, stunting, and finger clubbing along with anaemia. An investigation was carried out to determine the mechanism of the watery diarrhoea observed during infection which ceased upon expulsion of the worms. A hypothesis was proposed that the diarrhoea observed during the period of infection occurred as a result of the net secretion of chloride ions across the epithelium. This active secretion of chloride ions could be a consequence of the immunologically specific IgE antibody medicated response to antigens secreted by the helminth shown in previous studies. A preliminary determination of the concentration of the chloride ions in the stools of the infected children before and after treatment revealed a higher concentration of chloride ions in the stools collected before treatment. Rectal biopsies were clamped at zero voltage in Ussing chambers and challenged on the mucosal side with antigen derived from Trichuris trichiura. The short-circuit current, a measure of ion movement, was monitored. The specific chloride channel blocker, anthracene-9-carboxylic acid, and furosemide, a chloride pump blocker, were used to demonstrate that the secretory response to antigen was chloride ion mediated. The antihistamine, diphenhydramine hydrochloride, was used to demonstrate that histamine released from degranulating mast cells played an important role in the response. The viability of the biopsies was checked at the end of each experiment by challenging on the serosal side with acetylcholine chloride (AU)

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.

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.

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.

Controlling the spread of varicella zoster in the hospitalized patient.

In the health care setting, knowledge of communicable diseases is critical in the prevention of transmission. Communicable diseases transmitted by the respiratory route pose several difficult problems for control. One such disease, frequently overlooked in adults, because it is considered a childhood disease, is varicella zoster (chickenpox). Recognition of the disease and knowledge about its epidemiology, control, treatment, and follow-up care are necessary for the health care provider to prevent the spread of disease.

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.

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.

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.

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.

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.

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.

A factitious case of acquired immunodeficiency syndrome.

A 27-year-old man presented with a history of acquired immunodeficiency syndrome and the new onset of weakness and numbness of the lower extremities. During the course of a prolonged and extensive evaluation fraught with iatrogenic complications, it was discovered that his complaints were fabricated and his history of having acquired immunodeficiency syndrome was factitious.

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.