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Query: UMLS:C0019209 (hepatomegaly)
 5,798 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two Maltese puppies with massive hepatomegaly and failure to thrive had isolated deficient glucose-6-phosphatase (G-6-Pase) activity in liver and kidney and pathological findings compatible with GSD-Ia. To identify the mutation, we cloned G-6-Pase canine cDNA by RT-PCR with primers from the murine G-6-Pase gene sequence. The canine G-6-Pase cDNA is 2346 bp, with a 5' untranslated region of 87 bp, a coding region of 1071 bp, and a 3' untranslated region of 1185 bp. The difference between the canine and human sequences is in the 3' untranslated region. A greater than 90% amino acid sequence homology was seen with canine, human, murine, and rat G-6-Pase. G-6-Pase cDNA from affected and control puppies revealed complete homology except at nt position 450, which showed a guanine to cytosine (G to C) transversion resulting in substitution of a methionine by isoleucine at codon 121 (M121I) in all five clones studied. The loss of an NcoI restriction site on genomic DNA amplified with primers flanking the mutation allowed us to prove that affected puppies were homozygous for the mutation and parents were heterozygous carriers. The mutant G-6-Pase cDNA had 15 times less enzyme activity than wild-type cDNA following transient transfection. Northern blot analysis of puppies with GSD-Ia revealed increased G-6-Pase mRNA, compared to normal controls. Increased G-6-Pase mRNA was also seen in normal fasted puppies compared to littermates in the fed state, suggesting that the increased G-6-Pase mRNA is a physiologic response to fasting. This is the first report of a molecularly confirmed naturally occurring animal model of GSD-Ia. The establishment of a breeding colony of this dog strain will facilitate studies on the role of G-6-Pase gene in glucose homeostasis, in pathophysiology of disease, and development of novel therapeutic approaches such as gene therapy.
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PMID:Isolation and nucleotide sequence of canine glucose-6-phosphatase mRNA: identification of mutation in puppies with glycogen storage disease type Ia. 925 82

We report a new type of fatal mitochondrial disorder caused by selective deficiency of mitochondrial ATP synthase (ATPase). A hypotrophic newborn from a consanguineous marriage presented severe lactic acidosis, cardiomegaly and hepatomegaly and died from heart failure after 2 days. The activity of oligomycin-sensitive ATPase was only 31-34% of the control, both in muscle and heart, but the activities of cytochrome c oxidase, citrate synthase and pyruvate dehydrogenase were normal. Electrophoretic and western blot analysis revealed selective reduction of ATPase complex but normal levels of the respiratory chain complexes I, III and IV. The same selective deficiency of ATPase was found in cultured skin fibroblasts which showed similar decreases in ATPase content, ATPase hydrolytic activity and level of substrate-dependent ATP synthesis (20-25, 18 and 29-33% of the control, respectively). Pulse-chase labelling of patient fibroblasts revealed low incorporation of [(35)S]methionine into assembled ATPase complexes, but increased incorporation into immunoprecipitated ATPase subunit beta, which had a very short half-life. In contrast, no difference was found in the size and subunit composition of the assembled and newly produced ATPase complex. Transmitochondrial cybrids prepared from enucleated fibroblasts of the patient and rho degrees cells derived from 143B. TK(-)human osteosarcoma cells fully restored the ATPase activity, ATP synthesis and ATPase content, when compared with control cybrids. Likewise, the pattern of [(35)S]methionine labelling of ATPase was found to be normal in patient cybrids. We conclude that the generalized deficiency of mitochondrial ATPase described is of nuclear origin and is caused by altered biosynthesis of the enzyme.
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PMID:A novel deficiency of mitochondrial ATPase of nuclear origin. 1048 64

This paper reports clinical and metabolic studies of two Italian siblings with a novel form of persistent isolated hypermethioninaemia, i.e. abnormally elevated plasma methionine that lasted beyond the first months of life and is not due to cystathionine beta-synthase deficiency, tyrosinaemia I or liver disease. Abnormal elevations of their plasma S-adenosylmethionine (AdoMet) concentrations proved they do not have deficient activity of methionine adenosyltransferase I/III. A variety of studies provided evidence that the elevations of methionine and AdoMet are not caused by defects in the methionine transamination pathway, deficient activity of methionine adenosyltransferase II, a mutation in methylenetetrahydrofolate reductase rendering this activity resistant to inhibition by AdoMet, or deficient activity of guanidinoacetate methyltransferase. Plasma sarcosine (N-methylglycine) is elevated, together with elevated plasma AdoMet in normal subjects following oral methionine loads and in association with increased plasma levels of both methionine and AdoMet in cystathionine beta-synthase-deficient individuals. However, plasma sarcosine is not elevated in these siblings. The latter result provides evidence they are deficient in activity of glycine N-methyltransferase (GNMT). The only clinical abnormalities in these siblings are mild hepatomegaly and chronic elevation of serum transaminases not attributable to conventional causes of liver disease. A possible causative connection between GNMT deficiency and these hepatitis-like manifestations is discussed. Further studies are required to evaluate whether dietary methionine restriction will be useful in this situation.
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PMID:Glycine N-methyltransferase deficiency: a novel inborn error causing persistent isolated hypermethioninaemia. 1159 49

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a kind of inborn errors of metabolism, with the main clinic manifestations of jaundice, hepatomegaly, and abnormal liver function indices. As a mitochondrial solute carrier protein, citrin plays important roles in aerobic glycolysis, gluconeogenesis, urea cycle, and protein and nucleotide syntheses. Therefore citrin deficiency causes various and complicated metabolic disturbances, such as hypoglycemia, hyperlactic acidemia, hyperammonemia, hypoproteinemia, hyperlipidemia, and galactosemia. This paper reported a case of NICCD confirmed by mutation analysis of SLC25A13, the gene encoding citrin. The baby (male, 6 months old) was referred to the First Affiliated Hospital with the complaint of jaundice of the skin and sclera, which it had suffered from for nearly 6 months. Physical examination showed obvious jaundice and a palpable liver 5 cm below the right subcostal margin. Liver function tests revealed elevated enzymatic activities, like GGT, ALP, AST, and ALT, together with increased levels of TBA, bilirubin (especially conjugated bilirubin), and decreased levels of total protein/albumin and fibrinogen. Blood levels of ammonia, lactate, cholesterol, and triglyceride were also increased, and in particular, the serum AFP level reached 319,225.70 microg/L, a extremely elevated value that has rarely been found in practice before. Tandem mass analysis of a dried blood sample revealed increased levels of free fatty acids and tyrosine, methionine, citrulline, and threonine as well. UP-GC-MS analysis of the urine sample showed elevated galactose and galactitol. The baby was thus diagnosed with suspected NICCD based on the findings. It was then treated with oral arginine and multiple vitamins (including fat-soluble vitamins A, D, E, and K), and was fed with lactose-free and medium-chain fatty acids enriched formula instead of breast feeding. After half a month of treatment, the jaundice disappeared, and the laboratory findings, including liver function indices, blood levels of ammonia, lactate and AFP, were returned to normal level. The baby was followed up for 6 months. It developed well, and the abnormal laboratory findings, including MS-MS and UP-GC-MS analysis results, have been corrected, except a slightly elevated lactate level sometimes. SLC25A13 gene mutation analysis for the patient revealed a compound heterozygote of mutation 851del4 and 1638ins23 and therefore NICCD was definitely diagnosed.
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PMID:[A difficult and complicated case study: neonatal intrahepatic cholestasis caused by citrin deficiency]. 1661 6

Cystathionine gamma-lyase (CSE) is the last key enzyme in the transsulfuration pathway for the biosynthesis of cysteine from methionine in mammals, and catalyzes the hydrolysis of cystathionine into cysteine. Cysteine can be provided through diet; however, several investigators have suggested that infants may require dietary supplements of cysteine because of very low or undetectable CSE activity in their livers. We have previously shown that CSE levels are much lower in the livers and kidneys of fetal and infant mice than in those of adult mice, suggesting that the maternal supply of cysteine is important for the early development of mice. Here we examined changes of CSE expression in the livers and kidneys of dams during gestation and lactation. Hepatic enlargement was observed as early as gestational day 12.5 (G12.5) and thereafter became more prominent, whereas expression of CSE in the livers was found after postpartum day 1 (P1) and reached a peak at P14. The maintenance of lactation was essential for both hepatic enlargement and CSE expression. In contrast, kidneys gained weight only slightly during lactation while CSE expression in kidneys was markedly induced at G15.5 and then gradually declined through to P28. Serum concentrations of homocysteine (the precursor of cystathionine) were significantly lower in G18.5 dams than in virgins or G15.5 dams, suggesting that the expression of CSE in the kidneys contributes to the effective clearance of homocysteine during the late gestational stage.
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PMID:Differential induction of cystathionine gamma-lyase in the livers and kidneys of mouse dams during gestation and lactation. 1694 88

A male patient, born to unrelated Belgian parents, presented at 4 months with epistaxis, haematemesis and haematochezia. On physical examination he presented petechiae and haematomas, and a slightly enlarged liver. Serum transaminases were elevated to 5-10 times upper limit of normal, alkaline phosphatases were 1685 U/L (<720), total bilirubin was 2.53 mg/dl (<1.0), ammonaemia 69 microM (<32), prothrombin time less than 10%, thromboplastin time >180 s (<60) and alpha-fetoprotein 29723 microg/L (<186). Plasma tyrosine (651 microM) and methionine (1032 microM) were strongly increased. In urine, tyrosine metabolites and 4-oxo-6-hydroxyheptanoic acid were increased, but succinylacetone and succinylacetoacetate--pathognomonic for tyrosinemia type I--were repeatedly undetectable. Delta-aminolevulinic acid was normal, which is consistent with the absence of succinylacetone. Abdominal ultrasound and brain CT were normal.Fumarylacetoacetase (FAH) protein and activity in cultured fibroblasts and liver tissue were decreased but not absent. 4-hydroxyphenylpyruvate dioxygenase activity in liver was normal, which is atypical for tyrosinemia type I. A novel mutation was found in the FAH gene: c.103G>A (Ala35Thr). In vitro expression studies showed this mutation results in a strongly decreased FAH protein expression.Dietary treatment with phenylalanine and tyrosine restriction was initiated at 4 months, leading to complete clinical and biochemical normalisation. The patient, currently aged 12 years, shows a normal physical and psychomotor development.This is the first report of mild tyrosinemia type I disease caused by an Ala35Thr mutation in the FAH gene, presenting atypically without increase of the diagnostically important toxic metabolites succinylacetone and succinylacetoacetate.
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PMID:A novel mutation causing mild, atypical fumarylacetoacetase deficiency (Tyrosinemia type I): a case report. 2000 95

Liver regeneration is perhaps the most studied example of compensatory growth aimed to replace loss of tissue in an organ. Hepatocytes, the main functional cells of the liver, manage to proliferate to restore mass and to simultaneously deliver all functions hepatic functions necessary to maintain body homeostasis. They are the first cells to respond to regenerative stimuli triggered by mitogenic growth factor receptors MET (the hepatocyte growth factor receptor] and epidermal growth factor receptor and complemented by auxiliary mitogenic signals induced by other cytokines. Termination of liver regeneration is a complex process affected by integrin mediated signaling and it restores the organ to its original mass as determined by the needs of the body (hepatostat function). When hepatocytes cannot proliferate, progenitor cells derived from the biliary epithelium transdifferentiate to restore the hepatocyte compartment. In a reverse situation, hepatocytes can also transdifferentiate to restore the biliary compartment. Several hormones and xenobiotics alter the hepatostat directly and induce an increase in liver to body weight ratio (augmentative hepatomegaly). The complex challenges of the liver toward body homeostasis are thus always preserved by complex but unfailing responses involving orchestrated signaling and affecting growth and differentiation of all hepatic cell types.
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PMID:Principles of liver regeneration and growth homeostasis. 2372 Feb 94

Diverse etiologic events are associated with the development of hepatocellular carcinoma. During hepatocarcinogenesis, genetic events likely occur that subsequently cooperate with long-term exposures to further drive the progression of hepatocellular carcinoma. In this study, the frequent loss of the retinoblastoma (RB) tumor suppressor in hepatocellular carcinoma was modeled in response to diverse hepatic stresses. Loss of RB did not significantly affect the response to a steatotic stress as driven by a methionine- and choline-deficient diet. In addition, RB status did not significantly influence the response to peroxisome proliferators that can drive hepatomegaly and tumor development in rodents. However, RB loss exhibited a highly significant effect on the response to the xenobiotic1,4-Bis-[2-(3,5-dichloropyridyloxy)] benzene. Loss of RB yielded a unique proliferative response to this agent, which was distinct from both regenerative stresses and genotoxic carcinogens. Long-term exposure to 1,4-Bis-[2-(3,5-dichloropyridyloxy)] benzene yielded profound tumor development in RB-deficient livers that was principally absent in RB-sufficient tissue. These data demonstrate the context specificity of RB and the key role RB plays in the suppression of hepatocellular carcinoma driven by xenobiotic stress.
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PMID:RB tumor suppressive function in response to xenobiotic hepatocarcinogens. 2472 45

Non-alcoholic steatohepatitis (NASH) is characterised by hepatic steatosis, inflammation and fibrosis, which might progress to cirrhosis. Human NASH is associated with metabolic syndrome (MS). Currently, rodent NASH models either lack significant fibrosis or MS. ApoE(-/-) mice are a MS model used in cardiovascular research. The aim of this work was to establish and characterise a novel mouse NASH model with significant fibrosis and MS. ApoE(-/-) and wild-type mice (wt) were fed either a western-diet (WD), methionine-choline-deficient-diet (MCD) or normal chow. Liver histology, RT-PCR, hepatic hydroxyproline content, triglycerides and cholesterol levels, and fasting glucose levels assessed hepatic steatosis, inflammation and fibrosis. Further, portal pressure was measured invasively, and kidney pathology was assessed by histology. ApoE(-/-) mice receiving WD showed abnormal glucose tolerance, hepatomegaly, weight gain and full spectrum of NASH including hepatic steatosis, fibrosis and inflammation, with no sign of renal damage. MCD-animals showed less severe liver fibrosis, but detectable renal pathological changes, besides weight loss and unchanged glucose tolerance. This study describes a murine NASH model with distinct hepatic steatosis, inflammation and fibrosis, without renal pathology. ApoE(-/-) mice receiving WD represent a novel and fast model with all characteristic features of NASH and MS well suitable for NASH research.
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PMID:Seven weeks of Western diet in apolipoprotein-E-deficient mice induce metabolic syndrome and non-alcoholic steatohepatitis with liver fibrosis. 2626 22

Glycine N-methyltransferase deficiency is an inherited disorder of methionine metabolism, reported so far in only four patients and characterised by permanent hypermethioninemia. This disorder has been considered as probably benign because moderate hepatomegaly in two patients was the only obvious symptom and mild to moderate elevation of aminotransferases the only laboratory abnormality. Our experience with the current novel patient points out that this disease, due to very high hypermethioninemia, is not harmless and that there may be diagnostic pitfalls in interpretation of biochemical hallmarks of the disease. Since the first description of glycine N-methyltransferase deficiency, other disorders of this metabolic pathway affecting the liver have been reported pointing to dysmethylation as the common pathogenetic mechanism. Therefore, we suggest the whole group to be named dysmethylating liver diseases.
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PMID:Glycine N-Methyltransferase Deficiency: A Member of Dysmethylating Liver Disorders? 2720 70


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