Missed diagnoses of acute cardiac ischemia in the emergency department.

BACKGROUND: Discharging patients with acute myocardial infarction or unstable angina from the emergency department because of missed diagnoses can have dire consequences. We studied the incidence of, factors related to, and clinical outcomes of failure to hospitalize patients with acute cardiac ischemia. METHODS: We analyzed clinical data from a multicenter, prospective clinical trial of all patients with chest pain or other symptoms suggesting acute cardiac ischemia who presented to the emergency departments of 10 U.S. hospitals. RESULTS: Of 10,689 patients, 17 percent ultimately met the criteria for acute cardiac ischemia (8 percent had acute myocardial infarction and 9 percent had unstable angina), 6 percent had stable angina, 21 percent had other cardiac problems, and 55 percent had noncardiac problems. Among the 889 patients with acute myocardial infarction, 19 (2.1 percent) were mistakenly discharged from the emergency department (95 percent confidence interval, 1.1 to 3.1 percent); among the 966 patients with unstable angina, 22 (2.3 percent) were mistakenly discharged (95 percent confidence interval, 1.3 to 3.2 percent). Multivariable analysis showed that patients who presented to the emergency department with acute cardiac ischemia were more likely not to be hospitalized if they were women less than 55 years old (odds ratio for discharge, 6.7; 95 percent confidence interval, 1.4 to 32.5), were nonwhite (odds ratio, 2.2; 1.1 to 4.3), reported shortness of breath as their chief symptom (odds ratio, 2.7; 1.1 to 6.5), or had a normal or nondiagnostic electrocardiogram (odds ratio, 3.3; 1.7 to 6.3). Patients with acute infarction were more likely not to be hospitalized if they were nonwhite (odds ratio for discharge, 4.5; 95 percent confidence interval, 1.8 to 11.8) or had a normal or nondiagnostic electrocardiogram (odds ratio, 7.7; 95 percent confidence interval, 2.9 to 20.2). For the patients with acute infarction, the risk-adjusted mortality ratio for those who were not hospitalized, as compared with those who were, was 1.9 (95 percent confidence interval, 0.7 to 5.2), and for the patients with unstable angina, it was 1.7 (95 percent confidence interval, 0.2 to 17.0). CONCLUSIONS: The percentage of patients who present to the emergency department with acute myocardial infarction or unstable angina who are not hospitalized is low, but the discharge of such patients is associated with increased mortality. Failure to hospitalize is related to race, sex, and the absence of typical features of cardiac ischemia. Continued efforts to reduce the number of missed diagnoses are warranted.

Use of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) to assist with triage of patients with chest pain or other symptoms suggestive of acute cardiac ischemia. A multicenter, controlled clinical trial.

BACKGROUND: Approximately 6 million U.S. patients present to emergency departments annually with symptoms suggesting acute cardiac ischemia. Triage decisions for these patients are important but remain difficult. OBJECTIVE: To test whether computerized prediction of the probability of acute ischemia, used with electrocardiography, improves the accuracy of triage decisions. DESIGN: Controlled clinical trial. SETTING: 10 hospital emergency departments in the midwestern, southeastern, and northeastern United States. PATIENTS: 10689 patients with chest pain or other symptoms suggestive of acute cardiac ischemia. INTERVENTION: The probability of acute ischemia predicted by the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI), either automatically printed or not printed on patients' electrocardiograms. MEASUREMENTS: Emergency department triage to a coronary care unit (CCU), telemetry unit, ward, or home. Other measurements were the bed capacity of the CCU relative to that of the telemetry unit; training or supervision status of the triaging physician; and patient diagnoses and outcomes based on clinical, electrocardiographic, and creatine kinase data. RESULTS: For patients without cardiac ischemia, in hospitals with high-capacity CCUs and relatively low-capacity cardiac telemetry units, use of ACI-TIPI was associated with a reduction in CCU admissions from 15% to 12%, a change of -16% (95% CI, -30% to 0%), and an increase in emergency department discharges to home from 49% to 52%, a change of 6% (CI, 0% to 14%; overall P=0.09). Across all hospitals, for patients evaluated by unsupervised residents, use of ACI-TIPI was associated with a reduction in CCU admissions from 14% to 10%, a change of -32% (CI, -55% to 3%); a reduction in telemetry unit admissions from 39% to 31%, a change of -20% (CI, -34% to -2%); and an increase in discharges to home from 45% to 56%, a change of 25% (CI, 8% to 45%; overall P=0.008). Among patients with stable angina, in hospitals with high-capacity CCUs, use of ACI-TIPI was associated with a reduction in CCU admissions from 26% to 13%, a change of -50% (CI, -70% to -17%), and an increase in discharges to home from 20% to 22%, a change of 10% (CI, -29% to 71%; overall P=0.02). At hospitals with high-capacity telemetry units, use of ACI-TIPI was associated with a reduction in telemetry unit admissions from 68% to 59%, a change of -14% (CI, -27% to 1%), and an increase in emergency department discharges to home from 10% to 21%, a change of 100% (CI, 22% to 230%; overall P=0.02). Among patients with acute myocardial infarction or unstable angina, use of ACI-TIPI did not change appropriate admission (96%) to the CCU or telemetry unit at hospitals with high-capacity CCUs or telemetry units. CONCLUSIONS: Use of ACI-TIPI was associated with reduced hospitalization among emergency department patients without acute cardiac ischemia. This result varied as expected according to the CCU and cardiac telemetry unit capacities and physician supervision at individual hospitals. Appropriate admission for unstable angina or acute infarction was not affected. If ACI-TIPI is used widely in the United States, its potential incremental impact may be more than 200000 fewer unnecessary hospitalizations and more than 100000 fewer unnecessary CCU admissions.

Umbilical Cord Blood Mononuclear Cell HIV-1 LTR Binding Activities.

Vertically transmitted HIV disease constitutes a significant problem in pediatrics. In order to characterize some of the possible host factors involved in HIV replication in fetuses and newborns, we surveyed the HIV-1 LTR binding factors present in nuclear extracts from cord blood mononuclear cells. A series of electrophoretic mobility shift assays (EMSAs) showed that protein extracts from cord blood interacted with several regions of the HIV LTR. The most prominent binding activities involved the NF-kB sites, but other regions of the LTR also showed factor binding with the cord blood extracts. Some of these cord blood extract binding activities displayed qualitative differences when compared to adult peripheral blood mononuclear cell extracts in EMSA and UV cross-linking studies. Transient transfection experiments indicated that the NF-kB and Sp1 sequences were important for wild type levels of expression in cord blood cells, but that additional sequences 5' to the NF-kB sites also contributed activity. Thus, factors that interact with many of the well-known HIV LTR regulatory sites are present in cord blood cells. However, certain qualitative differences distinguished cord blood and adult peripheral blood binding activities and these may contribute to pathogenesis of HIV infection in neonates.

Syncytium induction in primary CD4+ T-cell lines from normal donors by human immunodeficiency virus type 1 isolates with non-syncytium-inducing genotype and phenotype in MT-2 cells.

Human immunodeficiency virus type 1 (HIV-1) isolates classified as syncytium-inducing (SI) or non-SI (NSI) in the MT-2 T-cell line exhibit characteristic sequence differences in the V1-V2 and V3 regions of the env gene. Seven HIV-1 isolates were phenotyped as NSI or SI in the MT-2 cell line. Unexpectedly, all four NSI viruses induced large syncytia 4 to 8 days postinoculation in a panel of five primary CD4+ T-cell lines (including two clones) generated from the peripheral blood of normal donors by exposure to infectious HIV-1, inactivated HIV-1, or Epstein-Barr virus. The primary T-cell lines yielded neither HIV-1 provirus nor infectious HIV by PCR analysis or exhaustive coculture with phytohemagglutinin-treated blast cells. Three isolates (TC354, PK1, and PK2) were biologically cloned and retained their SI or NSI phenotypes in MT-2 and primary T-cell lines. The biologically cloned provirus DNA was also used to clone and sequence the relevant V2 and V3 regions of the env genes. The amino acid sequences of the V2 and V3 regions were characteristic of patterns already reported for the NSI, switch NSI, and SI phenotypes, respectively. This evidence precludes the possibility that these results were due to contamination of the NSI isolates with SI virus. The results unequivocally indicate that HIV-1 isolates with the NSI genotype and phenotype in MT-2 cells may actively induce syncytia in cloned CD4+ T cells in vitro and support the view that direct cytopathic effects may contribute to the steady decline in CD4+ T cells in asymptomatic HIV-1-seropositive patients without detectable SI virus.

Identification of the respiratory syncytial virus-induced immunosuppressive factor produced by human peripheral blood mononuclear cells in vitro as interferon-alpha.

Respiratory syncytial virus (RSV) can inhibit the proliferative response of human peripheral blood mononuclear cells (PBMC) in vitro. This inhibition is mediated by an extracellular RSV-induced factor. In the present study, the factor was clearly identified as interferon (IFN)-alpha. The RSV-induced IFN-alpha bound strongly to PBMC and inhibited the anti-RSV proliferative response only when added within the first few days of stimulation. There was, however, no concomitant decrease in the production of interleukin (IL)-2 nor in the cell surface expression of CD25, CD71, and HLA-DR. Inhibition by RSV-induced IFN-alpha was unrelated to the levels of IL-1, -2, and -6 or of IFN-gamma induced by RSV in vitro or to the presence of IL-1 inhibitor, tumor necrosis factor-alpha, prostaglandin, or IL-10. Immunosuppression by IFN-alpha may significantly affect the outcome of infection and reinfection with RSV.

Diagnosis of human herpesvirus-6 infection in two patients with central nervous system complications.

BACKGROUND: Although exanthem subitum (ES) is generally a mild, self-limiting disease of early childhood, some cases of ES are complicated by seizures and encephalopathy. The presence of human herpesvirus-6 (HHV-6) DNA in cerebrospinal fluid (CSF) of these patients suggests that HHV-6 can infect the central nervous system (CNS) causing encephalitis. OBJECTIVES: To demonstrate HHV-6 infection in two patients with serious CNS complications. The patients, a child and an adult, failed to develop the characteristic rash normally associated with ES. STUDY DESIGN: Peripheral blood mononuclear cells (PBMCs) and CSF were examined for the presence of HHV-6 or viral DNA, using virus isolation techniques and the polymerase chain reaction (PCR). Serum samples were tested by immunofluorescence (IF) and enzyme linked immuno-sorbent assay (ELISA) for the presence of anti-HHV-6 IgM and anti-HHV-6 IgG respectively. RESULTS: HHV-6 was isolated from the PBMCs of the adult patient and the presence of virus in these cells was confirmed using electron microscopy. HHV-6 DNA was detected in CSF taken early during the infection in both patients, together with anti-HHV-6 IgM antibodies and increasing levels of anti-HHV-6 IgG. CONCLUSIONS: The diagnosis of HHV-6 infection in these patients was confirmed either by virus isolation or by the detection of HHV-6 DNA in the CSF, and the results of serology. These cases show that HHV-6 infection may result in serious CNS complications, in children and adults.

Southern blot analysis of skin biopsies for human papillomavirus DNA: renal allograft recipients in south-eastern Queensland.

The 104 skin biopsies from 34 patients who attended a Renal Transplant Unit in Brisbane over 12 months included 40 squamous cell carcinoma (SCC), 22 solar keratoses, 4 hyperkeratoses, 18 warts and 11 basal cell carcinoma (BCC). Human papillomavirus (HPV) DNA was identified by Southern blot hybridisation using, as individual probes, purified insert DNA from recombinant HPV 1, 2, 3 or 3/10, 4, 5 or 5/8, 7, 11, 16, 18 and 41 under relaxed conditions and characterised by restriction enzyme analysis and Southern blot hybridisation under more stringent conditions. Genomic HPV DNA was characterised in 7 skin biopsies from 4 renal allograft recipients (RARs): HPV 1A in a SCC (20 copies/cell) and a BCC (10 copies/cell) from the one patient, HPV 36 (20 copies/cell) in a SCC, HPV 1A [symbol: see text] 1000 copies/cell) in a wart and HPV 2B (200-800 copies/cell) in 3 warts from the one patient. Only HPV 1A in the SCC exhibited a significant degree of subtype variation. HPV DNA was identified in another 5 skin biopsies from another 4 RARs: HPV 3A in a wart and a hyperkeratosis, HPV 3/10-related DNA in 2 solar keratoses and HPV 5/8-related DNA in another (20-50 copies/cell). The incidence of HPV 5 (or 5-related HPVs) in RAR SCC was very low and that of HPV DNA in RAR warts was lower than that recorded elsewhere but this was not due to insensitivity of the assays. There was no evidence for a role for HPV in the aetiology of skin cancer in RARs in south-eastern Queensland but the possibility remains that as yet unidentified HPV types are involved.

Infectious respiratory syncytial virus (RSV) effectively inhibits the proliferative T cell response to inactivated RSV in vitro.

The effect of respiratory syncytial virus (RSV) on the cellular immune response of human mononuclear cells in vitro was examined. Inhibition by RSV of the lymphocyte response to phytohemagglutinin in vitro was confirmed using cells from human umbilical cord blood. In addition, RSV significantly inhibited both the proliferative and T cell colony responses of human mononuclear cells to Epstein-Barr virus. An RSV-specific cellular immune response was induced in vitro by stimulation of mononuclear cells from RSV-seropositive donors with beta-propiolactone-inactivated RSV. This RSV-specific response was significantly inhibited by infectious RSV itself, and the inhibition was mediated by an extracellular factor produced by RSV-infected mononuclear cells. A similar inhibition in vivo of the RSV-induced cellular immune response may contribute significantly to delayed recovery from primary infection and to reduced resistance to subsequent infections.

Effects of cycloheximide on B-chronic lymphocytic leukaemic and normal lymphocytes in vitro: induction of apoptosis.

A number of reports indicate that protein synthesis is a requirement for the occurrence of apoptosis. In this study, the effect of the protein synthesis inhibitor cycloheximide (CHM) on spontaneous apoptosis of B-chronic lymphocytic leukaemia (B-CLL) cells, previously shown to occur when they are cultured in RPMI-1640 medium with autologous or heterologous serum, was examined. No definite inhibition of apoptosis was observed. Indeed, CHM-treatment augmented apoptosis in the B-CLL cultures and also induced apoptosis of cultured normal peripheral blood lymphocytes. Augmentation was dose-dependent for B-CLL cells over the concentration range 10(-6) M (0.28 micrograms ml-1) to 10(-2) M (2800 micrograms ml-1), resulting in 9% to 98% apoptosis respectively by 24 h of culture (r = 0.619, P = 0.0008). Normal lymphocytes were affected by CHM over the range 10(-4) M to 10(-2) M, resulting in 7% to 74% apoptosis respectively (r = 0.794, P = 0.0001). Inhibition of protein synthesis in these cells by CHM was virtually complete at a concentration of 10(-3) M. The findings are in accord with some recent reports indicating that suppression of protein synthesis by CHM does not inhibit apoptosis in all circumstances. They also illustrate the marked susceptibility of B-CLL cells, compared with normal lymphocytes, to the induction of apoptosis by this drug. The manner in which CHM triggers apoptosis of some cell types is at present uncertain.

Western blot analysis of antibody specificities in subacute sclerosing panencephalitis: reactivity to measles virus proteins produced in persistently infected cells.

The specificity of serum antibodies from patients with subacute sclerosing panencephalitis (SSPE) and seropositive controls to measles virus proteins produced in acutely and persistently infected human cells was examined by western blot analysis. Sera from both SSPE patients and controls reacted to the H, N, and F1 virus proteins produced in acutely infected AV3 cells. However, while SSPE-derived sera reacted with the same proteins in persistently infected cells (AV3Al/MV), most control sera failed to react with the hemagglutinin protein produced in such cells (Hp). Most sera also reacted poorly with the M protein from either source, and the reactivity to the P protein was variable. Although the exact reason(s) for the different reactivities to the proteins were not determined, differences in antibody concentration did not appear to be responsible. The dramatic differences in the reactivity of SSPE and control sera to the Hp protein suggest that either the protein coevolves in persistent infections or multiple forms of the protein evolve in such infections and SSPE patients develop broad-spectrum humoral immunity as a consequence of exposure to them. Alternatively, over time there may be selective loss of some H-reactive antibody subsets by individuals who contract measles, but do not develop SSPE.

Interleukin-2 enhances production in 24 hours of infectious human immunodeficiency virus type 1 in vitro by naturally infected mononuclear cells from seropositive donors.

When peripheral blood mononuclear cells from HIV-1 seropositive patients were treated with rIL-2 in vitro a rapid increase of 2-12 fold in production of extracellular infectious HIV-1 occurred, in 6 of 9 experiments. Overall, the increase in the 9 experiments was significant (p less than 0.01) and provides more direct evidence for an enhancing role of IL-2 in naturally infected cells.

The value of MLA 144 culture fluid for the isolation of human immunodeficiency virus.

Human immunodeficiency virus (HIV) was readily isolated by co-cultivation of patients' cells with phytohaemagglutinin-stimulated mononuclear cells from umbilical cord blood in 2 ml cultures in 24-well plates. Fluids from cultures of the MLA 144 cell line acted as an excellent source of interleukin-2, and promoted early replication of HIV in the primary cultures. Reverse transcriptase activity was commonly present at significant levels by 4-7 days. In contrast, recombinant IL-2 (recIL-2) did not promote early replication under these conditions. Adequate washing of the phytohaemagglutinin blasts was critical in this system, although others have reported it to be less important under other culture conditions. Cell concentrations and HIV: target cell ratios appeared not to play a major role in early outgrowth of virus. The particular sheep anti-alpha interferon tested resulted in a two-fold reduction in RT activity. Virus was readily transmitted in this simplified cheaper culture system.

Spontaneous programmed death (apoptosis) of B-chronic lymphocytic leukaemia cells following their culture in vitro.

When B-chronic lymphocytic leukaemia (B-CLL) cells derived from peripheral blood were cultured in vitro, a substantial proportion of them spontaneously died by apoptosis. This type of cell death is morphologically and biochemically distinct from necrosis and has previously been found to occur under physiologic and certain pathologic conditions where cell deletion appears controlled and biologically meaningful. By 30 h of culture, approximately 20% of the unfractionated B-CLL cells were affected. There was no significant difference in the incidence of apoptosis in T-cell depleted and undepleted cultures or when either autologous or normal human serum was used. Furthermore, seeding densities of 2 x 10(6) and 5 x 10(5) cells/ml resulted in a similar incidence of apoptosis, indicating that cell density was unlikely to be a contributing factor in producing the death. The finding that B-CLL cells spontaneously die in vitro has at least two important implications. Firstly, previous work relating to some of the functions of B-CLL cells and their interactions with T cells may require re-evaluation. Secondly, an understanding of the mechanisms involved in the induction of apoptosis in this disease may have therapeutic consequences.

Epstein-Barr virus nuclear antigens 1 and 2 in Burkitt lymphoma cell lines containing either 'A'- or 'B'-type virus.

Epstein-Barr virus (EBV) has previously been classified into two different types according to the organization of the EB nuclear antigen 2 (EBNA2) gene region. Type A virus hybridizes with probes from B95-8 or M-ABA viruses and the B type virus with probes from the Jijoye virus strain. The substituted region in EBV type B codes for a different, but related EBNA2 antigen, named EBNA2B as opposed to EBNA2A. In this study Burkitt lymphoma cell lines, previously typed according to the EBV viral genomes they carry, as well as some matching lymphoblastoid cell lines were examined by immunoblotting for the expression of both EBNA1 and EBNA2 antigens. Variation in the molecular weight of EBNA1 indicated that both A and B virus types contained a variety of different virus isolates. EBNA2A was identified in all lines carrying A type viral genomes, but was not observed in any of the lines harboring B type virus. EBNA2B was identified in 4 of 10 Burkitt lymphoma lines carrying EBV type B.

Detection of Epstein-Barr virus strain variants in lymphoblastoid cell lines 'spontaneously' derived from patients with rheumatoid arthritis, infectious mononucleosis and normal controls.

'Spontaneous' lymphoblastoid cell lines (LCL) were established from patients with either rheumatoid arthritis (RA) or infectious mononucleosis (IM) or from healthy donors. Differences in Epstein-Barr virus (EBV) strains were determined by measuring the mol. wt. and expression of viral antigens in each of the LCLs. In addition to the previously reported EBV nuclear antigens, the LCLs also contained EBV-induced antigens with mol. wt. of 48K and 58K which were present in all but two of the lines. One of the differences observed between each of the groups of cell lines was their ability to produce viral antigens. Early and late antigens were identified by immunoblotting in most of the RA lines, two of the normal lines but none of the cell lines from patients with IM. Many of the IM cell lines were also found to express multiple EBNA1 antigens. The results demonstrate that a variety of wild-type EBV strains exist. However, the similarities observed in a number of the lines suggest that the diversity of strains may be limited.

The prevalence of antibodies to an Epstein-Barr virus-induced polypeptide (EBNA-2) in the sera of rheumatoid arthritic families.

Using the protein immunoblot technique, antibodies to an Epstein-Barr virus-induced 92 kD polypeptide (EBNA-2) were more frequently present in the sera of patients with rheumatoid arthritis and their consanguineous relatives when compared with a control group. No association of anti-EBNA-2 antibody with the HLA-DR antigens was observed.

Reactions of sera from patients with rheumatoid arthritis, systemic lupus erythematosus and infectious mononucleosis to Epstein-Barr virus-induced polypeptides.

P3HR-1 and Ramos cells induced with sodium butyrate and 12-O-tetradecanoylphorbol 13-acetate were used in the protein immunoblot technique to identify Epstein-Barr virus (EBV)-specific antibodies present in sera from clinically normal individuals and patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and infectious mononucleosis (IM). Sixteen EBV-specific polypeptides were detected ranging in mol. wt. from 22,000 (22K) to 140K. Many of the sera contained antibodies to different subsets of these antigens, and a high proportion expressed autoantibodies which reacted with cellular components from an EBV genome-negative cell line. About 50% of the sera from each category reacted with the 44K to 48K and 36K and 38K early antigen (EA) components. A high proportion of the SLE sera (64%) were found to contain anti-EA antibodies, suggesting an association between EBV and SLE. Almost all of the EBV-seropositive sera examined contained antibodies against a 22K late antigen, but none of the sera from IM patients reacted with this polypeptide.