A patient with hypertrophic cardiomyopathy accompanied by right ventricular dilation of unknown cause.
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Hypertrophic cardiomyopathy (HCM) is a disease characterized by an unknown cause of hypertrophy in the left or right ventricle. The dilated phase of HCM shows disease conditions resembling dilated cardiomyopathy, such as ventricular dilation, thin ventricular wall, and reduction of the ejection fraction. A patient presented with left ventricular concentric hypertrophy accompanied by right ventricular dilatation of unknown cause. Right ventricular endomyocardial biopsy specimens showed characteristic myocardial disarray. Therefore, there is the possibility that the patient had right and left ventricular HCM in the process toward the dilated phase, in which dilatation first occurred in the right ventricle. (+info)
Co-inherited Gilbert's syndrome: a factor determining hyperbilirubinemia in homozygous beta-thalassemia.
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BACKGROUND AND OBJECTIVE: Patients with thalassemia major and intermedia show a marked variability of serum indirect bilirubin levels. In this paper we tested the hypothesis related to the variability of the glucuronidation bilirubin rate which depends on the configuration of the A(TA)nTAA motif of the UGT1*1 glucuronosyltransferase gene promoter. DESIGN AND METHODS: We studied the configuration of the A(TA)nTAA motif in 26 patients with thalassemia major and 34 with thalassemia intermedia. RESULTS: In patients with thalassemia major and in those with thalassemia intermedia significantly higher bilirubin levels were found in patients with the (TA)7/(TA)7 genotype, than in those with the (TA)7/(TA)6 or (TA)6/(TA)6 genotype. INTERPRETATION AND CONCLUSIONS: These results indicate that the (TA)7/(TA)7 genotype, the configuration found in patients with Gilbert's syndrome, is capable of modifying the clinical phenotype of homozygous beta-thalassemia. This is an example of the role played by co-inherited modifying gene(s) on the extent of clinical heterogeneity of monogenic disorders. (+info)
Serum malondialdehyde concentration in babies with hyperbilirubinaemia.
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AIM: To determine lipid peroxide concentrations in the first 10 days of life. METHODS: Malondialdehyde concentrations were investigated in neonates with or without hyperbilirubinaemia during the first 10 days of life. RESULTS: Serum malondialdehyde concentrations were higher in infants with hyperbilirubinaemia than in controls. A positive correlation was found between malondialdehyde and bilirubin concentrations in the study group. When the study group was categorised according to the presence of haemolysis, a significant correlation was found between malondialdehyde and bilirubin concentrations in those infants with hyperbilirubinaemia due to haemolysis. There was no such correlation in those without haemolysis. CONCLUSION: Exchange transfusion rapidly produces variable changes in pro-oxidant and antioxidant plasma concentrations in neonates, which may be responsible for free radical metabolism. The fall in malondialdehyde concentration is probably directly related to its exogenous removal by exchange transfusion. (+info)
Effect of liver disease and transplantation on urea synthesis in humans: relationship to acid-base status.
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It has been suggested that hepatic urea synthesis, which consumes HCO-3, plays an important role in acid-base homeostasis. This study measured urea synthesis rate (Ra urea) directly to assess its role in determining the acid-base status in patients with end-stage cirrhosis and after orthotopic liver transplantation (OLT). Cirrhotic patients were studied before surgery (n = 7) and on the second postoperative day (n = 11), using a 5-h primed-constant infusion of [15N2]urea. Six healthy volunteers served as controls. Ra urea was 5.05 +/- 0.40 (SE) and 3.11 +/- 0.51 micromol. kg-1. min-1, respectively, in controls and patients with cirrhosis (P < 0. 05). Arterial base excess was 0.6 +/- 0.3 meq/l in controls and -1.1 +/- 1.3 meq/l in cirrhotic patients (not different). After OLT, Ra urea was 15.05 +/- 1.73 micromol. kg-1. min-1, which accompanied an arterial base excess of 7.0 +/- 0.3 meq/l (P < 0.001). We conclude that impaired Ra urea in cirrhotic patients does not produce metabolic alkalosis. Concurrent postoperative metabolic alkalosis and increased Ra urea indicate that the alkalosis is not caused by impaired Ra urea. It is consistent with, but does not prove, the concept that the graft liver responds to metabolic alkalosis by augmenting Ra urea, thus increasing HCO-3 consumption and moderating the severity of metabolic alkalosis produced elsewhere. (+info)
MRP3, a new ATP-binding cassette protein localized to the canalicular domain of the hepatocyte.
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Bile secretion in liver is driven in large part by ATP-binding cassette (ABC)-type proteins that reside in the canalicular membrane and effect ATP-dependent transport of bile acids, phospholipids, and non-bile acid organic anions. Canalicular ABC-type proteins can be classified into two subfamilies based on membrane topology and sequence identity: MDR1, MDR3, and SPGP resemble the multidrug resistance (MDR) P-glycoprotein, whereas MRP2 is similar in structure and sequence to the multidrug resistance protein MRP1 and transports similar substrates. We now report the isolation of the rMRP3 gene from rat liver, which codes for a protein 1522 amino acids in length that exhibits extensive sequence similarity with MRP1 and MRP2. Northern blot analyses indicate that rMRP3 is expressed in lung and intestine of Sprague-Dawley rats as well as in liver of Eisai hyperbilirubinemic rats and TR- mutant rats, which are deficient in MRP2 expression. rMRP3 expression is also transiently induced in liver shortly after birth and during obstructive cholestasis. Antibodies raised against MRP3 recognize a polypeptide of 190-200 kDa, which is reduced in size to 155-165 kDa after treatment with endoglycosidases. Immunoblot analysis and immunoconfocal microscopy indicate that rMRP3 is present in the canalicular membrane, suggesting that it may play a role in bile formation. (+info)
Neonatal bilirubin production, reflected by carboxyhaemoglobin concentrations, in Down's syndrome.
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AIM: To determine whether increased bilirubin production, reflected by blood carboxyhaemoglobin (COHb) values, is responsible for hyperbilirubinaemia in cases of Down's syndrome with no obvious cause for excessive jaundice. METHODS: Blood was sampled on the third day of life for COHb, total haemoglobin (tHb), and serum total bilirubin, from 19 consecutively born neonates with Down's syndrome (a subset of 34 term babies), who had developed hyperbilirubinaemia (serum bilirubin >/= 256 micromol), and from 32 term controls. COHb, measured by gas chromatography, was corrected for inspired CO (COHbc) and expressed as a percentage of tHb. RESULTS: Significantly more of the Down's syndrome subset developed hyperbilirubinaemia than the controls (10/19 (52%) vs 7/32 (22%), relative risk 2.4, 95% confidence intervals (CI) 1.10 to 5.26). Third day serum bilirubin values (mean (SD)) were higher in the Down's syndrome neonates than in controls (214 +- 63 micromol/l vs 172 +- 54 micromol/l, respectively, p=0.015). Mean (SD) COHbc values were significantly higher in the Down's syndrome neonates than in controls (0.92 +- 0. 24% vs 0.63 +- 0.17%; p<0.0001). However, Down's syndrome neonates who became hyperbilirubinaemic had similar COHbc values to those who did not (0.87 +- 0.26% and 0.95 +- 0.23%, respectively). These values contrast with those of the controls, in whom a significant increase in COHbc was associated with hyperbilirubinaemia (0.74 +- 0. 15% vs 0.60 +- 0.16%, respectively; p<0.05). tHb values were similar in both groups. CONCLUSIONS: Down's syndrome neonates had a greater risk of hyperbilirubinaemia, and higher COHbc values, than controls. However, excessive bilirubin production could not be exclusively responsible for the hyperbilirubinaemia. By inference, decreased bilirubin elimination probably plays a greater part in its pathogenesis than in controls. Down's syndrome neonates may have abnormal erythropoiesis, leading to increased haem turnover. (+info)
Retrospective review of cystic fibrosis presenting as infantile liver disease.
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The mode of presentation, clinical course, and outcome of 12 infants with cystic fibrosis and liver disease referred over an 18 year period were investigated retrospectively. Median age at presentation was 6.5 weeks (range, 5-12). Two thirds were boys. Conjugated hyperbilirubinaemia was the presenting symptom in 11 patients, and hypoalbuminaemia in one. Jaundice was cleared over a median period of 7.36 months. Eight patients had bile duct proliferation on liver biopsy and one required cholangiography to exclude biliary atresia. Classic histological features of cystic fibrosis were only present in two children biopsied at 8 and 18 months. Three patients had meconium ileus, including one infant with concomitant alpha(1) antitrypsin deficiency, who required early liver transplantation. All other patients had no signs of significant chronic liver disease during a median follow up of 42 months (range, 10-205). Children with cystic fibrosis and infantile liver disease have a good short and medium term prognosis. (+info)
Zinc protoporphyrin: A metabolite with a mission.
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Zinc protoporphyrin (ZnPP) is a normal metabolite that is formed in trace amounts during heme biosynthesis. The final reaction in the biosynthetic pathway of heme is the chelation of iron with protoporphyrin. During periods of iron insufficiency or impaired iron utilization, zinc becomes an alternative metal substrate for ferrochelatase, leading to increased ZnPP formation. Evidence suggests that this metal substitution is one of the first biochemical responses to iron depletion, causing increased ZnPP to appear in circulating erythrocytes. Because this zinc-for-iron substitution occurs predominantly within the bone marrow, the ZnPP/heme ratio in erythrocytes reflects iron status in the bone marrow. In addition, ZnPP may regulate heme catabolism through competitive inhibition of heme oxygenase, the rate-limiting enzyme in the heme degradation pathway that produces bilirubin and carbon monoxide. Physiological roles, especially relating to carbon monoxide and possibly nitric oxide production, have been suggested for ZnPP. Clinically, ZnPP quantification is valuable as a sensitive and specific tool for evaluating iron nutrition and metabolism. Diagnostic determinations are applicable in a variety of clinical settings, including pediatrics, obstetrics, and blood banking. ZnPP analytical methodologies for clinical studies are discussed. In addition to diagnostic tests and metabolic studies, ZnPP has a potential therapeutic application in controlling bilirubin formation in neonates as a preventive measure for hyperbilirubinemia. Biochemical research techniques, both in vivo and in vitro, are described for further studies into the role of ZnPP in metabolism and physiology. (+info)