Minimal hepatic encephalopathy in children: evaluation with proton MR spectroscopy.

BACKGROUND AND PURPOSE: Minimal hepatic encephalopathy (MHE) in children is difficult to evaluate because of lack of standardized neuropsychological tests for all age ranges. The purpose of this retrospective study of children with clinically suspected MHE was to investigate relationships between brain MR spectroscopy metabolites and biochemical markers of encephalopathy as well as measures of liver disease severity. MATERIALS AND METHODS: A total of 12 children (age range, 9-19 years; 8 female) with clinically suspected MHE were studied by short TE brain MR spectroscopy on a 1.5T magnet. We estimated gray matter (GM) and white matter (WM) metabolite concentrations using "LCModel" software. Regional metabolite concentrations were examined for correlation with various parameters, including plasma ammonia, the ratio of branched-chain to aromatic amino acids (BCAA/AAA), model for end stage liver disease/pediatric end stage liver disease (MELD/PELD) and Child-Pugh scores, bilirubin, albumin, and platelet counts. RESULTS: Myo-inositol (mIns) levels correlated with BCAA/AAA ratios (r = 0.86; P = .002 for GM and r = 0.77; P = .01 for WM). WM choline (Cho) levels and GM mIns levels showed significant negative correlation with ammonia levels (r = -0.58; P = .04 and r = -0.65; P = .02, respectively). A positive significant correlation trend was present for GM glutamine/glutamate (Glx) and ammonia levels (r = 0.66; P = .05). There was no correlation of brain MR spectroscopy parameters and severity of liver disease. CONCLUSIONS: Brain MR spectroscopy metabolites in children with suspected MHE show significant correlations with plasma ammonia levels and BCAA/AAA. As in adults, brain MR spectroscopy in children may be helpful in establishing a diagnosis of MHE.

Differential expression of vasopressin receptor binding in the hypothalamus during lactation in golden hamsters.

Vasopressin (AVP) receptor binding within hypothalamic sites was compared between cycling and lactating female golden hamsters. The density of AVP receptor binding was analyzed by quantitative autoradiography within the ventrolateral hypothalamus and dorsomedial hypothalamic nucleus. Lactation was correlated with a disappearance of AVP receptor binding within the ventrolateral hypothalamus. In contrast, lactation was associated with a two- to three-fold increase in the density of AVP receptor binding within the dorsomedial hypothalamic nucleus. These results suggest that AVP receptor binding within the ventrolateral hypothalamus is responsive to gonadal hormones in female golden hamsters. However, the increase in binding observed within the dorsomedial hypothalamus may be related to other neurobiological changes associated with lactation.