Anomalous drainage of the inferior caval vein to the left atrium.

We report a girl, aged 11(7/12) years, who presented with cyanosis. Cardiac catheterization showed occlusion of the infrahepatic segment of the inferior caval vein, with drainage of the hepatic veins into the left atrium. Transoesophageal echocardiography revealed an anomalous Eustachian valve that baffled the vein to the left atrium. This lesion is an extremely rare cause of cyanosis.

Cytotoxic effects of streptolysin o and streptolysin s enhance the virulence of poorly encapsulated group a streptococci.

Although the toxicity of streptolysin O (SLO) and streptolysin S (SLS) in purified group A streptococci (GAS) has been established, the effect of these molecules in natural infection is not well understood. To identify whether biologically relevant concentrations of SLO and SLS were cytotoxic to epithelial and phagocytic cells that the bacteria would typically encounter during human infection and to characterize the influence of cell injury on bacterial pathogenesis, we derived GAS strains deficient in SLO or SLS in the background of an invasive GAS M3 isolate and determined their virulence in in vitro and in vivo models of human disease. Whereas bacterial production of SLO resulted in lysis of both human keratinocytes and polymorphonuclear leukocytes, GAS expression of SLS was associated only with keratinocyte injury. Expression of SLO but not SLS impaired polymorphonuclear leukocyte killing of GAS in vitro, but this effect could only be demonstrated in the background of acapsular organisms. In mouse invasive soft-tissue infection, neither SLO or SLS expression significantly influenced mouse survival. By contrast, in a mouse model of bacterial sepsis after intraperitoneal inoculation of GAS, SLO expression enhanced the virulence of both encapsulated and acapsular GAS, whereas SLS expression increased the virulence only of acapsular GAS. We conclude that the cytotoxic effects of SLO protect GAS from phagocytic killing and enhance bacterial virulence, particularly of strains that may be relatively deficient in hyaluronic acid capsule. Compared to SLO, SLS in this strain background has a more modest influence on GAS pathogenicity and the effect does not appear to involve bacterial resistance to phagocytosis.

Natural history of serum immunoglobulin concentrations in low birth weight infants and association with respiratory tract infections.

UNLABELLED: Infections are a significant cause of morbidity and mortality among low birth weight (LBW) infants. THE AIMS OF OUR STUDY WERE: (1) to investigate whether serum antibody concentrations in 62 LBW infants (1,500-2,500 g) were normalized by 1 year of life, and (2) to determine the clinical relevance of humoral immaturity in these children during the 1st year compared to 20 appropriate-for-gestational-age (AGA) term infants. At 1 year of life, immunoglobulin serum concentrations in LBW infants were comparable to those of the control group. The incidence of respiratory tract infections during the 1st year of life was not significantly different between LBW and AGA term infants. Interestingly, we demonstrated that LBW infants with a higher frequency of reported febrile upper respiratory tract infections had more elevated serum total IgG, IgG(1), IgG(3), total IgA, and IgA(1) concentrations. Thus, infants with a birth weight of 1,500-2,500 g do not appear to have an increased risk of respiratory tract infections compared to AGA term children during the 1st year of life. Furthermore, our data suggest that especially febrile infections induce higher serum immunoglobulin concentrations in LBW infants.