Modulation of adhesion molecules and monocyte chemoattractant protein by tumor necrosis factor-alpha and salicylic acid in primary human coronary artery endothelial cells.

Kawasaki disease (KD) is an illness characterized by vascular inflammation of coronary arteries leading to coronary aneurysms and thromboses. Infiltration of immune cells into the intima and adventitia are observed in autopsy tissues of patients with KD. Using semi-quantitative RT-PCR and cell-based ELISA, we demonstrated that tumor necrosis factor-a induced the expression of intercellular adhesion molecules-1 and E-selectin, as well as monocyte chemoattractant protein-1, in a time- and dose-dependent manner in primary human coronary artery endothelial cell cultures. This increase was inhibited by salicylic acid (NaSal), and involved the transcription factor NF-kappaB. Based on these data, we suggest a pathogenetic mechanism for KD, whereby immune cells are attracted to sites of inflammation, undergo extravasation, release enzymes that assist in vascular remodeling, thereby weakening the endothelium and hastening the process of aneurysm formation. NaSal, in addition to preventing thrombosis and lowering fever in KD, may also function in down-regulating adhesion molecules during the inflammatory stage of KD.

A revised decision analysis of strategies in the management of febrile children at risk for occult bacteremia.

Two decision analysis reports published in 1991 concluded that the strategy of routine blood culture and empiric antibiotics was the superior strategy for febrile children at risk for occult bacteremia. This report describes a decision analysis of treatment strategies for these children considering the following changes that have occurred since then: (1) Hemophilus influenzae B incidence is low because of widespread vaccine use; (2) the emergence of resistant Streptococcus pneumoniae may affect the clinical effectiveness of empiric antibiotics in the future; and (3) the negative consequences of unnecessary antibiotic treatment have yet to be well defined. A decision analysis approach, modifying the original assumptions, was carried out. Sensitivity analyses were conducted on all assumption variables. Strategies employing empiric antibiotics were found to have the best outcomes, assuming low negative treatment consequences. If a high level of negative treatment consequences is assumed, strategies using a white blood cell count (WBC) are superior. If a very high level of negative treatment consequences is assumed, the strategy of no tests and no empiric antibiotic treatment is usually superior, unless the frequency of bacteremia is 10% or higher and empiric antibiotic efficacy is high, in which case a WBC strategy is superior. This information can be used to select a treatment strategy based largely on the estimation of the negative consequences of treatment.

Gowning does not affect colonization or infection rates in a neonatal intensive care unit.

OBJECTIVE: To study the effect of gowning in a neonatal intensive care unit on colonization patterns, necrotizing enterocolitis, respiratory syncytial virus and other infections, mortality, and traffic and handwashing patterns. METHODS: Alternate 2-month gowning and no-gowning cycles were established in a 24-bed level III neonatal intensive care unit for 8 months, with respiratory site, umbilical, and stool surveillance cultures done weekly on all patients. Traffic flow and handwashing compliance were evaluated by direct observation. RESULTS: Demographic data did not differ between periods. There were no significant differences between the gowning and no-gowning periods in the rates of bacterial colonization, any type of infection, or mortality. There was no effect on traffic flow or handwashing compliance. CONCLUSION: Gowning in the neonatal intensive care unit is an unnecessary custom without benefit in neonatal colonization, infection rates, mortality, traffic patterns, and handwashing behavior.

Characterization of T cell repertoire changes in acute Kawasaki disease.

Kawasaki disease (KD) is an acute multisystem vasculitis of unknown etiology that is associated with marked activation of T cells and monocyte/macrophages. Using a quantitative polymerase chain reaction (PCR) technique, we recently found that the acute phase of KD is associated with the expansion of T cells expressing the V beta 2 and V beta 8.1 gene segments. In the present work, we used a newly developed anti-V beta 2 monoclonal antibody (mAb) and studied a new group of KD patients to extend our previous PCR results. Immunofluorescence analysis confirmed that V beta 2-bearing T cells are selectively increased in patients with acute KD. The increase occurred primarily in the CD4 T cell subset. The percentages of V beta 2+ T cells as determined by mAb reactivity and flow cytometry correlated linearly with V beta expression as quantitated by PCR. However, T cells from acute KD patients appeared to express proportionately higher levels of V beta 2 transcripts per cell as compared with healthy controls or convalescent KD patients. Sequence analysis of T cell receptor beta chain genes of V beta 2 and V beta 8.1 expressing T cells from acute KD patients showed extensive junctional region diversity. These data showing polyclonal expansion of V beta 2+ and V beta 8+ T cells in acute KD provide additional insight into the immunopathogenesis of this disease.

Intravenous immune globulin for the prevention of nosocomial infection in low-birth-weight neonates. The Multicenter Group for the Study of Immune Globulin in Neonates.

BACKGROUND: Nosocomial infection is a major risk for premature infants with very low birth weights. One reason for their susceptibility to infection may be antibody deficiency, since there is little transfer of maternal IgG to the fetus before 32 weeks' gestation. METHODS: We conducted a multicenter, double-blind study of neonates weighing 500 to 1750 g at birth. A total of 588 neonates were randomly assigned, with stratification for birth weight, to receive periodic intravenous infusions of either immune globulin (500 mg per kilogram of body weight per day) or a placebo. Mortality, morbidity, and nosocomial infection during the next 56 days were assessed. RESULTS: The infusions were well tolerated; mild, reversible adverse reactions occurred in five infants in each group. There was a significant reduction in the risk of a first nosocomial infection in the recipients of immune globulin as compared with the placebo recipients (relative risk, 0.7; 95 percent confidence interval, 0.5 to 0.9). About 85 percent of the nosocomial infections were bacterial; the majority of these were caused by coagulase-negative staphylococci or Staphylococcus aureus. The neonates who received immune globulin had fewer mean days of hospitalization than the controls (62 vs. 68, P = 0.15); among the infants with infections, the difference in the mean length of the hospital stay was even greater (80 days vs. 101 days, P = 0.02). CONCLUSIONS: For premature infants weighing between 500 and 1750 g at birth, treatment with intravenous infusions of immune globulin is safe and reduces the risk of nosocomial infection.

Selective expansion of T cells expressing T-cell receptor variable regions V beta 2 and V beta 8 in Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis complicated by the development of coronary artery abnormalities. The etiology of KD is unknown. Based on the observation that KD is associated with marked activation of T cells and monocyte/macrophages, we hypothesized that KD may be caused by a superantigen [e.g., a bacterial toxin that stimulates T cells expressing particular T-cell receptor beta chain variable (V beta) gene segments]. Peripheral blood T cells from patients in the acute and convalescent phases of KD and from various control groups were analyzed for T-cell receptor V beta gene expression by using a quantitative PCR technique and cytofluorographic analysis with available anti-V beta monoclonal antibodies. Patients with acute KD demonstrated significantly elevated levels of circulating V beta 2+ and V beta 8.1+ T cells compared to the other control groups. none of the other 20 V beta populations analyzed by quantitative PCR were found to be significantly elevated. Using flow cytometry, we confirmed a significant elevation of T cells reactive with anti-V beta 8.1 and the lack of change in several other V beta subsets--i.e. V beta 5.1, -5.2, -6.7, and -12. During the convalescence phase of KD, there was a reduction in the abnormal levels of V beta 2+ and V beta 8.1+ T cells. These observations suggest that KD may be caused by a superantigen and may provide insight into the nature of the etiologic agent.

Hepatitis A outbreak in a neonatal intensive care unit: risk factors for transmission and evidence of prolonged viral excretion among preterm infants.

An outbreak of hepatitis A virus (HAV) infection in a neonatal intensive care unit (NICU) provided the opportunity to examine the duration of HAV excretion in infants and the mechanisms by which HAV epidemics are propagated in NICUs. The outbreak affected 13 NICU infants (20%), 22 NICU nurses (24%), 8 other staff caring for NICU infants, and 4 household contacts; 2 seropositive infants (primary cases) received blood transfusions from a donor with HAV infection. Risk factors for infection among nurses were care for a primary infant-case (relative risk [RR], 3.2), drinking beverages in the unit (odds ratio [OR], infinity), and not wearing gloves when taping an intravenous line (OR, 13.7). Among infants, risk factors were care by a nurse who cared for a primary infant-case during the same shift (RR, 6.1). Serial stool samples from infant-cases were tested for HAV antigen (HAV-Ag) by enzyme immunoassay and HAV RNA by nucleic acid amplification using the polymerase chain reaction. Infant-cases excreted HAV-Ag (n = 2) and HAV RNA (n = 3) 4-5 months after they were identified as being infected. Breaks in infection control procedures and possibly prolonged HAV shedding in infants propagated the epidemic in a critical care setting.

The impact of pediatric HIV infection on emergency services.

A thorough understanding of the spectrum and ramifications of pediatric HIV infection is important to the emergency physician. Rising reports of cases in rural populations and the vertical transmission from mother to infant are important changes in HIV epidemiology. Nearly all organ systems are either directly or indirectly involved and problems encountered, including diagnostic and therapeutic considerations by organ system, are reviewed. The role of the emergency physician in caring for HIV-infected infants and children includes recognition, timely treatment of complications, protection of self and other health care workers, and protection of the immunocompromised child.

Clinical and epidemiologic characteristics of patients referred for evaluation of possible Kawasaki disease. United States Multicenter Kawasaki Disease Study Group.

STUDY OBJECTIVES: (1) To determine those diseases that most often mimic Kawasaki disease (KD) in the United States. (2) To examine the physical findings and laboratory studies that influenced experienced clinicians to exclude the diagnosis of KD. (3) To compare epidemiologic features of patients with KD and patients referred for evaluation of possible KD in whom alternative diagnoses were established. DESIGN: Case comparison study. SETTING: Seven pediatric tertiary care centers. PATIENTS: Consecutive sample of 280 patients with KD and 42 comparison patients examined within the first 14 days after onset of fever. MEASUREMENTS AND MAIN RESULTS: (1) Infectious diseases, particularly measles and group A beta-hemolytic streptococcal infection, most closely mimicked KD and accounted for 35 (83%) of 42 patients in the comparison group. (2) The standard diagnostic clinical criteria for KD were fulfilled in 18 (46%) of 39 patients in whom other diagnoses were established. (3) Patients with KD were significantly less likely to have exudative conjunctivitis or pharyngitis, generalized adenopathy, and discrete intraoral lesions, and more likely to have a perineal distribution of their rash. The patients with KD were also more likely to have anemia and elevated erythrocyte sedimentation rate; leukocyte count less than 10 X 10(3)/mm3 and platelet count less than 200 X 10(3)/mm3 were significantly less prevalent in patients with KD. (4) Residence within 200 yards of a body of water was more common among KD patients. CONCLUSIONS: (1) Measles and streptococcal infection should be excluded in patients examined for possible KD. (2) Laboratory studies that may be useful in discriminating patients with KD from those with alternative diagnoses include hemoglobin concentration, erythrocyte sedimentation rate, and serum alanine aminotransferase activity. (3) Residence near a body of water may be a risk factor for the development of KD.

Epstein-Barr virus and other herpesvirus infections in Kawasaki syndrome.

Epstein-Barr virus (EBV), a possible cause of Kawasaki syndrome (KS), is not pathenogenically associated with KS in Hawaii. The prevalence of EBV capsid antibody in KS patients was found not to differ significantly from that in controls, and the antibody response in those infected with EBV was the same as that in other children similarly infected. No EBV was isolated from acute-phase patients. All patients with capsid antibody at the onset of KS also had Epstein-Barr nuclear antigen antibody: 36 patients developed antibody within 3 months after onset of KS; in 10, EBV infection could have been coincidental with the disease. Cytomegalovirus (CMV) was isolated from 9 patients with KS and 10 controls. A similar number of controls and patients had antibody to human herpesvirus 6 (HHV6); one patient seroconverted. None of the herpes viruses (EBV, CMV, HHV6, varicella-zoster virus, or herpes simplex virus) plays a unique or dominant role in the etiology or pathogenesis of KS in Hawaii.

Absence of significant RNA-dependent DNA polymerase activity in lymphocytes from patients with Kawasaki syndrome.

Kawasaki syndrome, an acute febrile multisystem illness of young children, is a panvasculitis with prominent rheumatic features. Arthritis and pancarditis are frequent during the acute stage; coronary artery aneurysms occur in 20% of cases and the disease is now the leading cause of acquired heart disease in childhood. A microbial aetiology is suggested by the acute febrile self-limited character of the disease, the regular occurrence of epidemic outbreaks at intervals of 2-3 years, and the virtual restriction to young children, consistent with the early acquisition of immunity. Reports of elevated DNA polymerase activity (assumed to be RNA-dependent reverse transcriptase) in cultured lymphocytes from patients with acute Kawasaki syndrome suggest that a retrovirus might be the causative agent. We have measured supernatant DNA polymerase activity in lymphocyte cultures from 49 Hawaiian patients in acute and convalescent stages of Kawasaki syndrome and have been unable to demonstrate significant reverse transcriptase activity or other evidence of involvement of a retrovirus in the aetiology of the disease.

Growth of toxic shock syndrome toxin 1-producing, tryptophan-requiring strains of Staphylococcus aureus associated with the presence of Escherichia coli.

More than 80 percent of TSST-1-positive strains of Staphylococcus aureus are tryptophan auxotrophs (Trp-). Chromosomal mapping has located the genetic determinant for TSST-1 (tst) in the trp operon for strain S411 (Trp-) and near the tyrB site for strain FRI1169 (Trp*). Auxonographic screening on tryptophan-free medium of 28 strains of S. aureus (TSST-1-positive and -negative, Trp+ and Trp-) against Escherichia coli (strains 6094, 7603, and 7877) and other strains of Enterobacteriaceae showed that Trp- S. aureus strains responded only to E. coli and tryptophan. Neither E. coli nor tryptophan inhibited TSST-1 production. Cocultivation of strain FRI1169 or S411 with E. coli strain 7877 showed that TSST-1 production by FRI1169 was not enhanced. In contrast, TSST-1 production by S411 was equal to that of S. aureus alone (less than 640 ng/mL) or enhanced (greater than 12,000 ng/mL) if the input log10 cfu of S. aureus was of equal or greater ratio to input E. coli and if the recovered S. aureus was greater than log10 5 cfu. These results suggest that nutritionally deficient toxicogenic strains of S. aureus may overcome growth limitation by coexisting in dynamic balance with strains of E. coli.

Endotoxin is not an essential mediator in toxic shock syndrome.

The hypothesis that toxic shock syndrome toxin 1 (TSST-1) exerts its deleterious effects in toxic shock syndrome (TSS) primarily by enhancing the lethality of small amounts of endogenous endotoxin derived from mucosal colonization with gram-negative bacteria was assessed by evaluating two means of inactivating endotoxin in rabbit models of TSS. In both of these models, toxins and TSST-1 are allowed to diffuse constantly from a subcutaneous depot. Immunologic inactivation of endotoxin with antiserum to the core lipopolysaccharide did not change the clinical course or mortality among animals infected with live TSS-associated staphylococci or among animals with a subcutaneous depot of TSST-1. Anti-TSST-1 was successful in preventing disease and death in these models. Pharmacologic inactivation of endotoxin by pretreatment or continuous treatment with polymyxin B did not prevent illness or mortality in the toxin depot model. Endotoxin thus appears not to be an essential mediator in TSS, since TSS-like illness develops and progresses despite inactivation of endotoxin in animal model systems that are faithful both physiologically and clinically to TSS in humans.

Vaginal tampon model for toxic shock syndrome.

The effects of tampon composition, inoculum size, and simulated menses on production of toxic shock syndrome toxin 1 (TSST-1) and toxic shock syndrome (TSS) were evaluated in a rabbit model that simulates tampon use in humans. Three small generic compressed-fiber tampons were successively inserted vaginally (remained in place 4.5 hours x 2; overnight x 1). Tampon no. 1 was inoculated with live TSST-1-positive staphylococci plus 5 mL of saline or simulated menses (defibrinated rabbit blood plus 2.5 g of bovine serum albumin/dL) immediately after insertion; saline or simulated menses alone were used with tampons no. 2 and 3. The vagina was washed after removal of tampon no. 3. TSS-like illness was produced consistently in animals with carboxymethyl cellulose/polyester foam tampons, which supported higher organism counts and greater TSST-1 production in association with subsequent tampons. Cotton and rayon tampons were not associated with as much clinical illness, organism growth, or TSST-1 production. Simulated menses supported toxin production and clinical illness when the inoculum was one-tenth that required for controls. Sham tampon insertion was associated with TSS-like illness in two of 10 rabbits; thus, other factors may promote TSS in the absence of vaginal tampons. This model reliability reproduces menstrual TSS, since one-time vaginal inoculation with TSST-1-positive staphylococci in the presence of blood and certain tampons leads to TSS, and may be useful in evaluating catamenial products and in understanding other factors important in TSST-1 production in vivo and the development of TSS.

Direct effects of purified staphylococcal toxic shock syndrome toxin 1 on myocardial function of isolated rabbit atria.

Toxic shock syndrome is associated with reversible cardiomyopathy. The cardiac dysfunction may be mediated by toxic shock syndrome toxin 1 (TSST-1), an exotoxin generated by Staphylococcus aureus. However, the effects of purified TSST-1 on cardiac function are unknown. In a study of the toxin's effect on myocardial function, TSST-1 (200 ng/mL) was added to muscle baths containing isolated rabbit atria. TSST-1 caused time-dependent inhibition of developed force (systolic function) but did not alter resting force (an index of muscle stiffness or cardiac compliance). These data show that TSST-1 can directly inhibit myocardial function, but the significance of this effect in patients with toxic shock syndrome remains to be determined.