Initial route of antigen administration alters the T-cell cytokine profile produced in response to the mouse pneumonitis biovar of Chlamydia trachomatis following genital infection.

A Th1-type response develops following vaginal infection with the mouse pneumonitis biovar of Chlamydia trachomatis (MoPn). Since the type of response, i.e., Th1 versus Th2, can be influenced by factors present during T-cell activation, we examined the effects of different routes of MoPn administration on the cytokine profile and resistance against infection following a MoPn vaginal challenge. A dominant Th1-type cytokine profile developed in mice given live MoPn via the intranasal, oral, and vaginal routes with ratios of gamma interferon-secreting cells to interleukin 4-secreting cells greater than 10. In contrast, mice injected subcutaneously produced a Th2-type profile with a gamma interferon/interleukin 4 ratio of only 0.7. These mice also had significantly higher anti-MoPn immunoglobulin G1 serum titers, confirming a Th2-type cytokine profile. Exposure of mice to live MoPn, by any route prior to vaginal challenge, resulted in a shortened course of infection. However, the subcutaneous group resolved the vaginal infection more slowly, with 60% (6 of 10 mice) of the mice still isolation positive 12 days after challenge compared with only 20% of mice given live MoPn by other routes. Administration of UV-inactivated MoPn did not provide protection against a vaginal challenge. The decreased ability to clear infection was not associated with a shift in the cytokine profile, since intranasal and oral administration of UV-inactivated MoPn resulted in a predominant Th1-type response. Taken together, these data indicate that the initial route of MoPn administration can direct the type of response produced after a local MoPn infection and thus influence the ability of the immune response to protect against subsequent infection.     

Factors predicting cases with unexpected clinical findings at necropsy.

AIMS/BACKGROUND: A major medical role for postmortem examinations is the detection of clinically unexpected disease processes contributing to death. The aim of the present study was to determine whether simple clinical parameters can predict the presence of important unanticipated findings at necropsy. METHODS: Prospective audit of adult necropsies carried out in a single year to assess the extent of unexpected findings at necropsy, to compare these cases with non-necropsied deaths to confirm they are a similar population and to seek features that predict which cases have unexpected necropsy findings. RESULTS: No correlation was found between age, sex, duration of in-hospital treatment, surgical intervention, clinical specialty, or necropsy request rates and incidence of unexpected findings in 187 adult necropsies. CONCLUSIONS: No parameters have been identified for patient selection to permit an increase in the yield of clinically unexpected findings. Until there is clear evidence that the current practice of patient selection is anything more than random, an increase in postmortem examination rates, as proposed by the Joint Working Party of the Royal College of Pathologists, the Royal College of Physicians of London and the Royal College of Surgeons of England in their report The Autospy and Audit, will increase the workload without necessarily producing a commensurate gain in knowledge.     

Alterations of the myocardial skeletal framework in acute myocardial infarction with and without ventricular rupture. A preliminary report

Thinning and dilatation (expansion) of the infarct region and complete rupture of the ventricular wall are significant complications of acute transmural myocardial infarction associated with increased morbidity and mortality. The pathogenesis of these related events is unknown. Recent studies of myocardial connective tissue have delineated an extensive array of intercellular and pericellular structures which serve as a skeletal framework and which may modulate contractile activity. We have employed a modified silver impregnation method to visualize the connective tissue components by light microscopy. To explore whether the skeletal framework is altered in acute myocardial infarction with and without ventricular rupture, we studied 9 human hearts at autopsy, and 4 canine infarcts of known duration. The human infarctions included 4 nonruptured cases with infarcts 1-5 days old, and 5 ruptured cases with infarcts 3-10 days old. Sections from normal, lateral, and central infarct or ventricular rupture sites were stained with silver. The normal tissue from each heart served as a control. Silver staining was moderately decreased in the lateral infarct zones, and markedly decreased in the central non-ruptured infarct zones. In the 5 ventricular rupture cases, the rupture site had no silver staining. A similar pattern was observed in the 4 canine infarcts. Thus, we conclude that the skeletal framework is markedly altered in the central zone of acute myocardial infarction. The acute changes of silver stained connective tissue may contribute significantly to the development of infarct expansion or ventricular wall rupture.     

Chemiluminescent response to pathogenic organisms: normal human polymorphonuclear leukocytes

Chemiluminescence (CL) is a sensitive indicator of phagocytosis and intracellular killing; however, little is known of the normal CL response by human polymorphonuclear leukocytes to different pathogenic microorganisms. We investigated the luminol-enhanced CL response of normal polymorphonuclear leukocytes to a number of common bacterial pathogens and two yeasts. We analyzed the CL response to viable and heat-killed microorganisms at 25 and 37 degrees C. The CL response to all microorganisms was greater and more rapid at 37 degrees C. Variable responses were observed with viable and heat-killed microorganisms; some were unaffected, whereas other demonstrated reduced CL. Each microorganism caused a reproducible response pattern, which could be placed into two general categories. In the first category were those which caused a rapid exponential rise and decay in CL: Enterobacter cloacae, Salmonella typhimurium, Shigella flexneri, Staphylococcus aureus, Candida albicans, and zymosan. In the second category were those which rose slowly over a longer time course to a poorly defined peak: Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, and Streptococcus pyogenes. The CL response also reflected serum opsonic activity. The effect of inactivated complement, factor B, and removal of specific antibody were investigated. Increasing the concentration of zymosan gave a proportional rise in peak CL; however, a strain of E. coli caused a variation in peak time rather than peak height. Different CL kinetics were shown for three strains of K. pneumoniae, possibly a result of each having different membrane or cell wall characteristics. This study defines the nature and factors affecting the normal CL response to a variety of common pathogenic microorganisms.     

Endogenous glutathione and catalase protect cultured rat astrocytes from the iron-mediated toxicity of hydrogen peroxide

Primary astrocyte cultures from rat brain were exposed to hydrogen peroxide (H2O2) to investigate peroxide toxicity and clearance by astrocytes. After bolus application of H2O2 (100 microM), the peroxide was eliminated from the incubation medium following first-order kinetics with a half-time of approximately 4 min. The rate of peroxide detoxification was significantly slowed by pre-incubating the cells with the glutathione synthesis inhibitor buthionine sulfoximine (BSO), or the catalase inhibitor 3-amino-1,2,4-triazole (3AT), and was retarded further when both treatments were combined. H2O2 application killed a small proportion of cells, as indicated by the levels of the cytosolic enzyme lactate dehydrogenase in the media 1 and 24h later. In contrast, cell viability was strongly compromised when the cells were pre-incubated with 3AT and/or BSO before peroxide application. The iron chelator deferoxamine completely prevented this cell loss. These results demonstrate that chelatable iron is involved in the toxicity of H2O2 and that both the glutathione system and catalase protect astrocytes from this toxicity.     

IgG antibodies to the histone complex H2A-H2B characterize procainamide-induced lupus

Patients treated with procainamide and other drugs commonly develop antinuclear antibodies and occasionally symptoms of lupus erythematosus. However, the pathological events which lead to clinical symptoms in some patients but only abnormal serology in others have not been established. The present study examines the incidence, amount, immunoglobulin class, and antigen-binding specificity of anti-histone and anti-denatured DNA (anti-dDNA) antibodies in three groups of patients. These comprised a prospective study of patients treated with procainamide, patients with clinical drug-induced lupus symptoms, and a group undergoing therapy for many years without any symptoms. Procainamide elicited IgG and IgM anti-dDNA antibodies concordantly. Anti-histone IgM antibodies also appeared de novo during this period but IgG anti-histone antibodies were detected less frequently. Asymptomatic patients tended to have an antibody profile consisting of highly elevated anti-dDNA, IgM antibodies reactive with all histones and IgG antibodies specific for only one or two histone classes. In contrast symptomatic patients usually had little anti-dDNA or antibodies to individual histones but had pronounced IgG antibodies to the histone complex H2A-H2B. This unique antibody was characteristics of procainamide-induced lupus and was not detected in patients whose disease was induced by hydralazine. Anti-(H2A-H2B) decreased after procainamide was discontinued, concomitant with subsidence of symptoms. The finding that autoantibodies elicited by procainamide in patients with lupus symptoms have a characteristic immunoglobulin class and specificity may be of pathogenic significance and suggests that patients susceptible to procainamide-induced lupus have a unique immune response. In addition, this information could be of diagnostic value in predicting which procainamide-treated patients will develop overt symptoms of lupus.     

A molecular and FISH analysis of structurally abnormal Y chromosomes in patients with Turner syndrome

Fourteen patients with Turner syndrome and a structurally abnormal Y chromosome were analysed by PCR amplification and fluorescence in situ hybridisation for the presence of sequences specific to defined regions of the Y chromosome. Thirteen patients had a mosaic karyotype including a 45,X cell line and one case was non-mosaic in cultured lymphocytes. Ten patients had a pseudodicentric Yp chromosome, two an isodicentric Yq, one a pseudodicentric Yq, and one a derived Y chromosome. Two of the patients with a psu dic(Yp) chromosome had complex karyotypes with more than two cell lines, one of which exhibited five morphologically distinct mar(Y) chromosomes, presumably derived from a progenitor psu dic(Yp). Nine of the ten psu dic(Yp) chromosomes were positive for all Yp and Yq probes used except DYZ1 which maps to Yq12, suggesting a common breakpoint near the Yq euchromatin/heterochromatin boundary. In the three patients with a dicentric Yq chromosome two different breakpoints were observed; in two it was between PABY and the subtelomeric repeat sequence and in one it was between DYZ5 and AMGY in proximal Yp. Our results suggest that the great majority of structurally abnormal Y chromosomes found in Turner syndrome mosaics contain two copies of virtually all of the functional Y chromosome euchromatin.     

Influence of major histocompatibility complex haplotype on the mitogenic response of T cells to staphylococcal enterotoxin B.

The abilities of antigen-presenting cells (APC) from nine independent major histocompatibility complex haplotypes and a number of intra-H-2 recombinant congenic strains of mice to present staphylococcal enterotoxin B (SEB) and induce proliferation in murine T-cell receptor V beta 8+ T-cell clones were compared. SEB presented by APC of all haplotypes tested induced significant responses in each of the T-cell clones. The magnitude of response was similar for most haplotypes, but there were limited quantitative differences between certain haplotypes. SEB presented by APC from H-2b mice as well as the intra-H-2 recombinant strains B10.GD and B10.A(4R), which do not express cell surface I-E (designated I-E-), induced the poorest T-cell responses. However, APC from AfE-, AsE-, and AqE- mice were as potent in SEB presentation as APC expressing both I-A and I-E. Antibodies against I-E were more effective than anti-I-A antibodies at inhibiting responses to SEB presented by APC expressing both I-A and I-E, whereas responses induced by APC expressing I-A but not I-E were blocked by antibodies against I-A. Thus, our results show that I-A can present SEB efficiently but that expression of both I-A and I-E on the same APC results in presentation of SEB predominantly by I-E. In addition, experiments using four distinct I-E- strains of mice indicate that I-A alleles differ in their ability to present SEB.     

Ocular measurements in fetal alcohol spectrum disorders

Fetal alcohol spectrum disorders (FASD) describe a range of physical, behavioral, and neurologic deficits in individuals exposed to alcohol prenatally. Reduced palpebral fissure length is one of the cardinal facial features of FASD. However, other ocular measurements have not been studied extensively in FASD. Using the Fetal Alcohol Syndrome Epidemiologic Research (FASER) database, we investigated how inner canthal distance (ICD), interpupillary distance (IPD), and outer canthal distance (OCD) centiles differed between FASD and non‐FASD individuals. We compared ocular measurement centiles in children with FASD to non‐FASD individuals and observed reductions in all three centiles for ICD, IPD, and OCD. However, when our non‐FASD children who had various forms of growth deficiency (microcephaly, short‐stature, or underweight) were compared to controls, we did not observe a similar reduction in ocular measurements. This suggests that reductions in ocular measurements are a direct effect of alcohol on ocular development independent of its effect on growth parameters, which is consistent with animal models showing a negative effect of alcohol on developing neural crest cells. Interpupillary distance centile appeared to be the most significantly reduced ocular measure we evaluated, suggesting it may be a useful measure to be considered in the diagnosis of FASD.