Regulation of in vitro and in vivo T cell activation by CD43

Accessory molecule interactions can be critical in determining the outcome of a T cell's encounter with antigen. Cell adhesion proteins may augment T cell responses by facilitating TCR engagement of the antigen-MHC complex, while co-stimulatory molecules may deliver distinct signals that modulate T cell responsiveness. CD43 (leukosialin, sialophorin) has been suggested to influence cell activation by steric hindrance based upon the large size and glycosylation of the protein, as well as the relative abundance of the protein on the cell surface. In this paper we examine both in vitro and in vivo T cell-dependent responses in CD43-deficient mice. We demonstrate that T cells from CD43-deficient mice are hyper-responsive following both in vivo and in vitro activation, and that this is observed in response to not only TCR-CD3-mediated stimulation, but also following receptor-independent activation. This data suggests that mechanisms other than non-specific steric hindrance are important in the regulation of T cell activation by CD43.      

Painful piezogenic pedal papules

A case of painful piezogenic pedal papules is reported. The histological findings are compatible with the hypothesis that the papules are caused by harniation of fat into the dermis.     

Chronic Q Fever

Sixteen cases of chronic Q fever are described. In eight therewas a history of exposure to infection from farms or farm products.All had valvular heart disease, involving the mitral valve innine and the aortic valve in seven. Infection occurred on aprosthetic valve in two patients. Arterial embolism was common.Venous thrombosis occurred in three patients, and pulmonaryembolism occurred in three other patients. Complement fixing antibodies to phase 1 antigen were found ina titre of 1:200 or greater in all except two patients. In oneof these post-mortem examination revealed rickettsial bodiesin mitral valve vegetations, and in the other Coxiella burnetiwas isolated from heart valve tissue. The majority presented with infective endocarditis but two presentedprimarily with liver disease. All patients had evidence of liverinvolvement and in one this led to death from cirrhosis. Abnormaltests of liver function, particularly hyperglobulinaemia, raisedalkaline phosphatase and abnormal bromsulphthalein retentionwere found in all patients. Hepatic histology was abnormal inall eight patients in whom it was studied. The commonest featureswere mononuclear cell infiltration of the portal tracts andprominence of the sinusoidal Kupffer cells. Patchy focal necrosisof parenchymal cells, granulomata, fatty change, and eosinophiliaof the sinusoidal walls were also noted in several patientsand cirrhosis developed in one. Six patients had a purpuric rash, and in 12 there was thrombocytopenia.It is suggested that the presence of hepatomegaly and liverinvolvement and thrombocytopenia may help to differentiate Qfever endocarditis from bacterial endocarditis. Raised serum IgM and IgA levels occurred frequently, but withonly a moderate dominance of IgM. Sheep cell agglutination andlatex fixation tests for rheumatoid factor were occasionallypositive. Several features of the disease suggest the possibilitythat immune-complex mechanisms may play a role in chronic Qfever. Treatment was with prolonged courses of tetracycline usuallycombined with lincomycin. Seven patients underwent valve replacementsurgery for haemodynamic reasons. Five patients died; two fromheart failure, one from cirrhosis, one seven days after valvereplacement and one from intraperitoneal haemorrhage followingpercutaneous liver biopsy. Three patients have survived for more than five years, and anothersix for more than three and a half years after diagnosis. Ofthese nine patients, three received medical therapy alone andsix required valve replacement as well. Antibiotics have beendiscontinued in four patients who have had valve surgery andthree others. Six patients had received antibiotics for continuousperiods varying from 29–62 months. In the period afterstopping therapy varying from 15–21 months, no relapsehas occurred. A seventh patient, who had received antibioticsfor four months prior to valve replacement, has survived 43months after the withdrawal of antibiotics. It is suggested that antibiotic therapy with tetracycline andlincomycin may control the disease, and that valve surgery maynot be necessary to achieve this. In view of the known propensityfor this organism to persist in a quiescent form for long periodseven without treatment, we recommend careful monitoring of thesepatients after treatment is withdrawn.     

Predictive value of, and observer variability in, several ways of reporting antepartum cardiotocographs

Summary. Each of three scoring systems, and oscillatory frequency, had significantly poorer correlation with fetal outcome than reporting the cardiotocograph (CTG) as either 'reactive' or 'non-reactive'. There was no significant difference in the intra- and inter-observer variability when the CTG was reported in this way.     

Gated MR imaging of left atrial myxomas

Two cases of left atrial myxoma were evaluated with magnetic resonance (MR) imaging. In both cases, the myxoma was clearly defined as to its location, origin, and size. In one case, the myxoma prolapsed through the mitral valve. Our study indicates that MR imaging is valuable in the diagnosis of myxomas.