Biomedical subjects

Linjun Xie

Publications and source records attributed to Linjun Xie.

3 recordsLinked to original sources

PubMed2005

Cardiac aspergillosis in patients with acquired immunodeficiency syndrome: a case report and review of the literature.

Cardiac aspergillosis is uncommon in patients with acquired immunodeficiency syndrome (AIDS) in the absence of open heart surgery. We report a unique case of a 62-year-old man with AIDS who developed Aspergillus pancarditis with Aspergillus vegetations on mitral valve without evidence of pulmonary aspergillosis. There was extensive embolization to the brain and multiple foci of Aspergillus infection in kidneys and adrenal glands. There are only 10 documented cases of cardiac aspergillosis in the literature (1966-2003) in severely immunocompromised AIDS patients with CD4 T-lymphocyte counts ranging from 10 to 121 cells/muL. The cardiac aspergillosis could result from invasive pulmonary aspergillosis, either by hematogenous dissemination or by direct invasion, and skin Aspergillus infection can be carried through the bloodstream to the right heart in intravenous drug abusers. Most of the reported cases of cardiac aspergillosis were diagnosed at autopsy. Mortality among AIDS patients with cardiac aspergillosis is 100%, despite appropriate therapy.

AIDS-Related Opportunistic Infections↗

PubMed2004

Argininosuccinate synthetase is reversibly inactivated by S-nitrosylation in vitro and in vivo.

Prior studies have demonstrated that the substrate for NO synthesis, l-arginine, can be regenerated from the NOS co-product l-citrulline. This requires the sequential action of two enzymes, argininosuccinate synthetase (AS) and argininosuccinate lyase (AL). AS activity has been shown to be rate-limiting for high output NO synthesis by immunostimulant-activated cells and represents a potential site for metabolic control of NO synthesis. We now demonstrate that NO mediates reversible S-nitrosylation and inactivation of AS in vitro and in lipopolysaccharide-treated cells and mice. Using a novel mass spectrometry-based method, we show that Cys-132 in human AS is the sole target for S-nitrosylation among five Cys residues. Mutagenesis studies confirm that S-nitrosylation of Cys-132 is both necessary and sufficient for the inhibition of AS by NO donors. S-nitroso-AS content is regulated by cellular glutathione levels and selectively influences NO production when citrulline is provided to cells as a protosubstrate of NOS but not when l-arginine is provided. A phylogenetic comparison of AS sequences suggests that Cys-132 evolved as a site for post-translational regulation of activity in the AS in NOS-expressing species, endowing NO with the capacity to limit its own synthesis by restricting arginine availability.

Animals↗

PubMed2004

Aortic dissection.

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Aortic Dissection↗