Mycobacterium avium Complex Infection in a Patient with Sickle Cell Disease and Severe Iron Overload.

A 34-year-old female with sickle cell anemia (hemoglobin SS disease) and severe iron overload presented to our institution with the subacute presentation of recurrent pain crisis, fever of unknown origin, pancytopenia, and weight loss. A CT scan demonstrated both lung and liver nodules concerning for granulomatous disease. Subsequent biopsies of the liver and bone marrow confirmed the presence of noncaseating granulomas and blood cultures isolated Mycobacterium avium complex MAC. Disseminated MAC is considered an opportunistic infection typically diagnosed in the immunocompromised and rarely in immunocompetent patients. An appreciable number of mycobacterial infection cases have been reported in sickle cell disease patients without immune dysfunction. It has been reported that iron overload is known to increase the risk for mycobacterial infection in vitro and in vivo studies. While iron overload is primarily known to cause end organ dysfunction, the clinical relationship with sickle cell disease and disseminated MAC infection has not been reported. Clinical iron overload is a common condition diagnosed in the sub-Saharan African population. High dietary iron, genetic defects in iron trafficking, as well as hemoglobinopathy are believed to be the etiologies for iron overload in this region. Patients with iron overload in this region were 17-fold more likely to die from Mycobacterium tuberculosis. Both experimental and clinical evidence suggest a possible link to iron overload and mycobacterial infections; however larger observational studies are necessary to determine true causality.

Hypertension and a missing kidney.

Standard initial assessment via ultrasound of a 4-year-old girl with hypertension revealed the absence of one kidney. Instead of cross-sectional imaging of the retroperitoneal space, a functional (nuclear) study was performed. This revealed a malformed kidney within the chest. Though systemic levels of renin and aldosterone were not elevated, removal of the malformed kidney normalized the blood pressure. The presence of prominent smooth muscle nodules surrounding the arteries was seen in the malformed kidney. Initial attempts to avert surgery by pharmacologically reducing blood flow to the malformed kidney were unsuccessful. The review of the literature offers little evidence to support such a strategy.

Murine prolylcarboxypeptidase depletion induces vascular dysfunction with hypertension and faster arterial thrombosis.

Prolylcarboxypeptidase (PRCP) activates prekallikrein to plasma kallikrein, leading to bradykinin liberation, and degrades angiotensin II. We now identify PRCP as a regulator of blood vessel homeostasis. ß-Galactosidase staining in PRCP(gt/gt) mice reveals expression in kidney and vasculature. Invasive telemetric monitorings show that PRCP(gt/gt) mice have significantly elevated blood pressure. PRCP(gt/gt) mice demonstrate shorter carotid artery occlusion times in 2 models, and their plasmas have increased thrombin generation times. Pharmacologic inhibition of PRCP with Z-Pro-Prolinal or plasma kallikrein with soybean trypsin inhibitor, Pro-Phe-Arg-chloromethylketone or PKSI 527 also shortens carotid artery occlusion times. Aortic and renal tissues have uncoupled eNOS and increased reactive oxygen species (ROS) in PRCP(gt/gt) mice as detected by dihydroethidium or Amplex Red fluorescence or lucigenin luminescence. The importance of ROS is evidenced by the fact that treatment of PRCP(gt/gt) mice with antioxidants (mitoTEMPO, apocynin, Tempol) abrogates the hypertensive, prothrombotic phenotype. Mechanistically, our studies reveal that PRCP(gt/gt) aortas express reduced levels of Kruppel-like factors 2 and 4, thrombomodulin, and eNOS mRNA, suggesting endothelial cell dysfunction. Further, PRCP siRNA treatment of endothelial cells shows increased ROS and uncoupled eNOS and decreased protein C activation because of thrombomodulin inactivation. Collectively, our studies identify PRCP as a novel regulator of vascular ROS and homeostasis.

Cardiomyopathy in Coffin-Lowry syndrome.

Coffin-Lowry syndrome (CLS) is a rare but well-documented X-linked disorder characterized by small size, developmental delay/mental retardation, and characteristic facial and skeletal findings in affected males. The phenotype in affected females is far more variable and can include developmental differences, obesity, and characteristic facial and skeletal differences. Cardiac anomalies are reported in less than 20% of affected males, with cardiomyopathy being one of the rare but reported complications of this disorder. However, cardiomyopathy is not well characterized in CLS. Here, we report on a 14-year-old boy with physical and developmental findings consistent with CLS who presented with a relatively sudden onset of signs of congestive heart failure due to a restrictive cardiomyopathy; an endomyocardial biopsy demonstrated non-specific hypertrophic myocyte alterations consistent with cardiomyopathy. This is the first description of the histology and electron microscopy of cardiomyopathy in CLS.

Minipump induced hyperoxaluria and crystal deposition in rats: a model for calcium oxalate urolithiasis.

PURPOSE: Unraveling the mechanisms leading to clinically active calcium oxalate (CaOx) stone disease and the development of effective medical therapies to treat it have been hampered by the lack of appropriate animal models. To address this problem we developed a model of hyperoxaluria and calcium oxalate crystal deposition by implanting osmotic minipumps subcutaneously into male rats, that is minipump induced hyperoxaluria and crystal deposition in rats. MATERIALS AND METHODS: Male Harlan-Sprague Dawley rats (225 to 290 gm) were implanted subcutaneously with 1-week 2 ml osmotic minipumps containing 1.5 M potassium oxalate (360 microM KOx/24 hours, [KOx-trt], 11) or phosphate buffered saline (PBS-trt, 9) on days 1 and 7. The 24-hour urine collections were performed on days 0, 4, 7, 11 and 14. Data were analyzed by ANOVA and Tukey's HSD. Urinary crystals were analyzed by light microscopy. Kidneys were harvested on day 14 and processed for light and polarizing microscopy, and RNA analysis.RESULTS Mean overall creatinine excretion +/- SEM (PBS-trt 107 +/- 7 and KOx-trt 123 +/- 6 microM/24 hours, p >0.07) and day 14 serum creatinine (PBS-trt 83 +/- 4 and KOx-trt 83 +/- 5 microM, p >or=0.9) were similar in the 2 treatment groups. Overall urinary volume (PBS-trt 11.3 +/- 0.8 and KOx-trt 18.0 +/- 1.5 ml/24 hours, p