Immune regulation of procalcitonin: a biomarker and mediator of infection.

Procalcitonin (PCT) has recently emerged as a powerful biomarker for an early and accurate diagnosis of bacterial infection. Here we summarize our current understanding of the expression pathways of PCT, its potential cellular sources including immune cells, and factors inducing its secretion. Also addressed is the significance of increased blood PCT concentration, which may allow this molecule not only to act as a clinical biomarker but also as an active participant in the development and progression of infectious processes. Experimental approaches to delineate a better understanding of PCT functions, molecular pathways that modulate its expression and therapeutic opportunities to curtail its biological actions are discussed, as well.

A computerized medical incident reporting system for errors in the intensive care unit: initial evaluation of interrater agreement.

Errors resulting in adverse events in the medical care system are ubiquitous and underreported. Critical incident techniques that have been used to reduce errors in aviation have recently been applied to evaluate adverse events in the critical care arena. We report an evaluation of interrater agreement on responses to questions concerning adverse event reporting using a computer-based medical incident reporting system (MIRS). Thirty-four intensive care unit staff volunteers reviewed five fabricated test cases containing iatrogenic factors, then completed an incident report for each case using the MIRS. Interrater agreement was significant for all five cases (p < 0.01). The time required to complete a report decreased significantly from the first case to the last (p < 0.01). Overall, the MIRS was perceived as a relatively quick (< 6 minutes) and comprehensive reporting tool. The results indicate that health care providers report adverse events similarly, suggesting that the MIRS would be a useful tool in the reduction of errors (as a process improvement program) and to facilitate the continuing process of health care improvement.

Fluorometric method for the enzymatic determination of cholesterol.

A fluorometric method for the enzymatic determination of cholesterol content has been developed using a novel fluorogenic H2O2 probe, Amplex Red. This assay is performed in a 96-well microplate, and it is a one-step method amenable to automated procedures. Using commercially available cholesterol, our assay allows detection of 5 pmol (2 ng) cholesterol per well, which is 100-fold more sensitive than published fluorometric and colorimetric methods. When applied to the measurement of cholesterol levels in serum and food samples, the Amplex Red-based method has been found more attractive since the oxidation product of the Amplex Red method has superior long wavelength spectra which are less susceptible to interference from the biological compounds.

Gonadal hormones influence the immune response to PLP 139-151 and the clinical course of relapsing experimental autoimmune encephalomyelitis.

Females have an increased incidence of multiple sclerosis (2:1). This gender dimorphism can be studied effectively using a murine model of relapsing experimental autoimmune encephalomyelitis (R-EAE). We demonstrated previously that male SJL mice immunized with proteolipid protein (PLP) peptide 139-151 developed an initial episode of paralysis, but failed to relapse. In the present study, clinical EAE relapses were induced by orchidectomy. Relapses in castrated mice were accompanied by an influx of activated CD4+, Th1 cells into the CNS which were absent in sham mice. Our data suggests an important regulatory role for androgens on the immune response to PLP 139-151 and the clinical course of R-EAE.

Anti-enolase-alpha autoantibodies in cancer-associated retinopathy: epitope mapping and cytotoxicity on retinal cells.

Patients with cancer-associated retinopathy syndrome (CAR), a progressive blinding disease related to retinal degeneration and systemic tumor outside the eye, develop autoantibodies against alpha-enolase. A small percentage of healthy subjects without evident tumor or visual symptoms also possess autoantibody against enolase. In these studies we examined the fine specificity of anti-enolase antibodies derived from patients with CAR and healthy individuals, using synthetic peptides covering the entire sequence of human alpha-enolase. Epitope mapping revealed that three binding regions of enolase within the residues 31-38 (FRAAVPSG), 176-183 (ANFREAMR), and 421-428 (AKFAGRNF) were common for all autoantibodies tested. However, pathogenic sera recognized an additional unique region, the sequence 56-63 (RYMGKGVS). There were also differences in in vitro cytotoxic activities on E1A.NR3 retinal cells and cell-death promoting activities between anti-enolase antibodies of healthy and CAR affected individuals. These studies showed that anti-enolase antibodies from patients with CAR were able to induce apoptotic cell death in E1A.NR3 retinal cells and provided a potential mechanism for retinal degeneration in humans.

Similar pattern of MCP-1 expression in spinal cords and eyes of Lewis rats with experimental autoimmune encephalomyelitis associated anterior uveitis.

Monocyte chemoattractant protein-1 (MCP-1) is a member of the CC chemokine family responsible for the recruitment of T cells that have been found during inflammation of the spinal cord in experimental autoimmune encephalomyelitis (EAE) in Lewis rats immunized with myelin basic protein (MBP). Lewis rats injected with MBP also developed anterior uveitis (AU), which coincided with the onset of EAE. In the present studies, we examined the expression and distribution of MCP-1 in the eye and spinal cord during disease and compared it to the expression of Th1 cell type cytokines. Initially, MCP-1 expression was detected at the preclinical phase in the iris/ciliary body and lumbar spinal cord and increased during the course of EAE/AU. Mononuclear infiltrating cells and endothelial cells and astrocytes of the CNS could be identified as a source of MCP-1 by in situ hybridization. Kinetics of expression of Th1 characteristic cytokines such as IL-2 and IFNgamma was in agreement with the expression of MCP-1 chemokine. Moreover, induction of the gene expression of MCP-1 seemed to occur earlier than that of MIP-2, and it correlated with increasing disease severity. MCP-1 seems to contribute to the initial recruitment of inflammatory cells into both the tissues of the eye and CNS over the course of disease.

Epitope recognition of recoverin in cancer associated retinopathy: evidence for calcium-dependent conformational epitopes.

Recoverin, a photoreceptor-specific calcium-binding protein, is a target for antibodies in human cancer-associated retinopathy. We have studied the binding properties of antirecoverin human autoantibodies and rat monoclonal antibodies (MAbs). The majority of antibodies to recoverin, both in human disease and in animals immunized with recoverin, are directed against the same major immunodominant region, the sequence within the residue 64-70 in proximity to the calcium-binding domain EF-hand 2. The immunodominant epitopes consist of linear and conformational components. Our data demonstrate that the reactivity of autoantibodies was dependent on conformational changes induced by the binding of calcium to recoverin. Some patients' antibodies could be detected by immunocytochemical methods and enzyme linked immunosorbent assay (ELISA); however, their binding was abolished on Western blots; their epitopes were sensitive to SDS treatment. Immunization of Lewis rat with purified recoverin induces antibodies with properties strikingly similar to human autoantibodies. Comparison between the monoclonal antibodies (MAbs) and native autoantibodies showed that the calcium-induced changes in conformation were critical for specificities of the antibody generated. The recoverin region within the sequence 61-82 is a key region for antibody binding; it also contains a major T-cell epitope, and it is highly uveitogenic in Lewis rats.

Myelin basic protein specific T-helper cells induce experimental anterior uveitis.

Immunopathological changes in the eyes were examined in Lewis rats after active and passive induction of experimental autoimmune encephalomyelitis (EAE) with myelin basic proteins (MBP) at various stages of EAE. The onset of anterior uveitis (AU) coincided with hind limb paralysis, but uveitis persisted after clinical signs of EAE had subsided. A mild form of uveitis was characteristic for the majority of rats. The changes within the iris and ciliary body consisted of an accumulation of inflammatory cells lining the anterior surface of iris, the trabecular meshwork, and, in some cases, within the ciliary body and the aqueous humor. A similar histopathological picture was observed when rats were injected with the secondary encephalitogenic determinant for Lewis rats, MBP peptide 87-99. Flow cytometry analysis of T cells from the anterior segment of the inflamed eyes after immunization with MBP revealed the presence of CD4+ cells exclusively expressing V beta 8.2 and OX-40 markers. Our data suggest that MBP are encephalitogenic and uveitogenic in Lewis rats and that the V beta 8.2-positive T cells in the eye represent encephalitogenic T cells. Many of those T cells were distributed in the iris and the anterior chamber. These findings indicate that these MBP-specific T cells may play a critical role in EAE as well as in AU.

Spontaneous regression of a giant pulmonary bulla.

Gradual expansion of a lung bulla is common and may be associated with debilitating pulmonary symptoms. The aetiology of bulla expansion is unclear. Spontaneous regression, on the other hand, is rarely observed. The case is presented of a man in whom near complete spontaneous resolution of a giant pulmonary bulla occurred. This event was associated with dramatic improvement in the radiographic picture and pulmonary function.

Recoverin, a photoreceptor-specific calcium-binding protein, is expressed by the tumor of a patient with cancer-associated retinopathy.

Recoverin is a member of the EF-hand family of calcium-binding proteins involved in the transduction of light by vertebrate photoreceptors. Recoverin also was identified as an autoantigen in the degenerative disease of the retina known as cancer-associated retinopathy (CAR), a paraneoplastic syndrome whereby immunological events lead to the degeneration of photoreceptors in some individuals with cancer. In this study, we demonstrate that recoverin is expressed in the lung tumor of a CAR patient but not in similar tumors obtained from individuals without the associated retinopathy. Recoverin was identified intially by Western blot analysis of the CAR patient's biopsy tissue by using anti-recoverin antibodies generated against different regions of the recoverin molecule. In addition, cultured cells from the biopsy tissue expressed recoverin, as demonstrated by reverse transcription-PCR using RNA extracted from the cells. The immunodominant region of recoverin also was determined in this study by a solid-phase immunoassay employing overlapping heptapeptides encompassing the entire recoverin sequence. Two linear stretches of amino acids (residues 64-70, Lys-Ala-Tyr-Ala-Gln-His-Val; and 48-52, Gln-Phe-Gln-Ser-Ile) made up the major determinants. One of the same regions of the recoverin molecule (residues 64-70) also was uniquely immunopathogenic, causing photoreceptor degeneration upon immunization of Lewis rats with the corresponding peptide. These data demonstrate that the neural antigen recoverin more than likely is responsible for the immunological events associated with vision loss in some patients with cancer. These data also establish CAR as one of the few autoimmune-mediated diseases for which the specific self-antigen is known.

The problem central venous catheter.

Central venous catheter complications are an important nosocomial problem. This report outlines three complications of central line placement and provides some insights that may help physicians and surgeons avoid consequential problems with invasive line placement.

Analysis of 3,294 cases of upper gastrointestinal bleeding in military medical facilities.

OBJECTIVES: Upper gastrointestinal bleeding (UGIB) remains a commonly encountered medical emergency with significant morbidity and mortality. Most large studies detailing the specific incidence, demographic, and mortality data were performed more than a decade ago. This study analyzes 3,294 cases of UGIB from 139 military medical treatment facilities over a 12-month period. METHODS: A retrospective chart review of Department of Defense military medical treatment facilities for UGIB was performed from October 1990 through September 1991. Core data such as demographic information were analyzed, as well as specific data relating to UGIB. RESULTS: The incidence of UGIB was 36 per 100,000 population with a male-to-female ratio of 2.18 and a mean age of 52 +/- 19.65 yr. The number of cases increased with age; 44.5% of all patients were > or = 60 yr old. The overall mortality was 7.0% (231 of 3294), and death rates were similar among males and females (7.1% vs. 6.8%) with an odds ratio of 1.03 (CI: 0.77-1.402). Mortality increased with age in both genders; 73.2% of deaths occurred in patients more than 60 yr old. Comorbid illness was noted in 50.9% (1675 of 3294) of patients, with similar occurrence in males (48.7%) and females (55.4%). One or more comorbid illnesses were noted in 98.3% of the patients who died, and in 72.3% of cases, they were the primary cause of death. Bleeding was the primary cause of death in 18.6% of patients. Upper endoscopy was performed in 68.8% of cases, therapeutic endoscopy in 12.6%, repeat endoscopy in 10.7%, and surgery in 4.4%. Blood transfusions were administered in 47.3% of cases, with most patients receiving < 5 units of blood. Rebleeding after initial hemostasis was noted in 7.1% of cases. Factors related to increased mortality include age > 60 (p < 0.001), transfusion requirement > 5 U (p < 0.001), presence of comorbid illness (p < 0.001), rebleeding after initial hemostasis (p < 0.005), surgery (p < 0.001), and UGIB occurring during hospitalization (p = 0.027). CONCLUSIONS: We conclude: 1) The incidence of UGIB is 2-fold greater in males than in females, in all age groups; however, the death rate is similar in both sexes. 2) The mortality rate in this study is slightly lower than in most previous studies and may be more reflective of the average mortality in the community at large. 3) In UGIB patients, comorbid illness and not actual bleeding is the major cause of death. 4) Upper endoscopy was performed less often in this study than in other studies, and there were fewer blood transfusions; however, rebleeding and mortality rates remained similar.