Acute Liver Failure in an Adolescent Male Induced by Human Herpesvirus 6 (HHV-6): A Case Report With Literature Review.

A previously healthy 11-year-old Caucasian boy presented with a 2-week history of nonspecific symptoms of nausea and nonbilious, nonbloody emesis. He developed significant jaundice and hepatic encephalopathy within 1 week of beginning symptoms and was discovered to have fulminant liver failure. Extensive work-ups for underlying etiologies included serologic evaluation for underlying chronic liver diseases, toxicology screening, inborn errors of metabolism, and infectious diseases. The results of the entire assessment were negative except for human herpesvirus 6B, which was detected in the liver by quantitative real-time polymerase chain reaction and immunohistochemical analysis. The patient underwent ABO-compatible liver transplantation and has had clinically stable health, with no evidence to date of complications associated with HHV-6 or other members of the herpesvirus family.

Magnetic resonance imaging identifies unsuspected liver abnormalities in patients after the Fontan procedure.

OBJECTIVE: To determine whether abdominal magnetic resonance imaging (MRI) detects hepatic abnormalities before clinical or biochemical perturbations in patients after the Fontan procedure. STUDY DESIGN: Thirty-nine children and adolescents who underwent the Fontan procedure and were referred to a pediatric hepatologist by cardiology services between 2011 and 2012 were reviewed retrospectively. Physical examination findings, routine laboratory tests of liver function, evaluation for chronic liver disease, and abdominal MRI findings were recorded. MRI findings were evaluated relative to time elapsed since surgery by 2 radiologists (blinded). RESULTS: Assessment for coexisting chronic liver disease was negative in all patients. All patients had a normal serum albumin level and International Normalized Ratio. Twenty-six of the 39 patients (67%) underwent abdominal MRI, 4 had MRI-incompatible hardware, and 9 did not undergo MRI because of insurance denial. All MRI scans demonstrated morphologic liver changes with varying degrees of reticular contrast enhancement compatible with fibrosis and congestion. Reticular contrast enhancement was often nonuniform, and 9 patients (35%) had multifocal arterially enhancing lesions. CONCLUSION: MRI can identify hepatic abnormalities in patients after Fontan surgery that go undetected by standard clinical and laboratory assessments. These abnormalities are not uniformly distributed throughout the liver, and thus assessment by liver biopsy analysis is subject to sampling error.

Ontogeny of bradykinin B1 receptors in the mouse kidney.

Kinins are vasoactive peptides that stimulate two G-protein coupled bradykinin receptors (B1R and B2R). B2R-knockout mice are salt sensitive and develop renal dysgenesis and hypertension if salt stressed during embryogenesis. B1R-knockout mice, on the other hand, are protected from inflammation and fibrosis. This study examined the spatiotemporal expression of B1R during renal organogenesis. The segmental nephron identity of B1R immunoreactivity was determined by costaining with markers of the collecting duct (Dolichos biflorus), proximal tubule (Dolichos tetraglonus), and nephron progenitors (Pax2). At E14.5, the B1R was confined to few cells in the metanephric mesenchyme. Abundance of B1R increased progressively during development. On E17.5, B1R was enriched in differentiating proximal tubular cells and by postnatal day 1, B1R was clearly expressed on the luminal aspect of the proximal tubule. Quantitative real-time PCR revealed that the levels of B1R mRNA more than double during renal maturation. We conclude that 1) B1R expression correlates closely with nephron maturation; 2) lack of B1R in nephron progenitors suggests that B1R is unlikely to play a role in early nephrogenesis; and 3) enrichment of B1R in maturing proximal tubule suggests a potential role for this receptor in terminal differentiation of the proximal nephron.