Chromosomes of the liver fluke, Clonorchis sinensis

A karyological study was carried out in order to compared the chromosome numbers, chromosome morphologies and karyotypes of the oriental liver fluke, Clonorchis sinensis (Trematoda: Opisthorchiidae), collected from Korea and China. Chromosome preparations were made by means of air-drying method. The chromosome number was 2n = 56 in both Korean and Chinese flukes, and chromosomes were divided into two groups based on this size; consisting of 8 pairs of large and 20 pairs of small chromosomes. However, the karyotypes showed some differences between Korean and Chinese flukes. The karyotype of liver flukes from Korea consisted of three metacentric pairs, one meta-/submetacentric pair, 16 submetacentric pairs and eight subtelocentric pairs of chromosomes. On the other hand, liver flukes from China consisted of two metacentric pairs, two meta-/submetacentric pairs, 16 submetacentric pairs and eight subtelocentric pairs of chromosomes.     

Serum triglycerides, the liver and the pancreas

Massive hypertriglyceridaemia associated with fatty liver and abdominal pain or frank pancreatitis (the chylomicronaemia syndrome) is uncommon, but clinically important and under-recognized. It may arise as a result of severe genetic defects in lipolysis or, more commonly, from a moderate primary hypertriglyceridaemia that is exacerbated by a secondary cause. The latter include several drugs, among which the protease inhibitors, used for the treatment of human immunodeficiency virus infection, are increasingly apparent. In the acute situation plasma exchange, fat-free parenteral nutrition and acute insulin treatment, even in nondiabetic persons, may be valuable. A potentially major advance in prophylaxis is the use of high-dose antioxidant therapy, which has been shown to reduce attacks of pancreatitis even in the absence of a reduction in serum triglycerides. Asymptomatic patients with abnormal liver function tests are common in the lipid clinic, and can be a difficult group in which to make management decisions. Among those who are not taking excessive amounts of alcohol, many will have nonalcoholic steatohepatitis. The care of these patients is discussed, but there remains considerable uncertainty regarding their optimum management and prognosis.     

Ethanol, the choline requirement, methylation and liver injury

The findings obtained in this laboratory and others over the past decade are discussed in order to formulate a thesis, indicating the adverse action of ethanol on a vital methylation process in the liver. Evidence is shown that the rat may have a means of compensating for this impairment in methylation whereas humans do not have this same ability to protect against this action of ethanol. These considerations may offer a basis of why rats are apparently more resistant to alcoholic liver injury than humans.     

Level of nitrated proteins in the plasma,platelets and liver of patients with liver cirrhosis

Abstract

Over-expression of nitric oxide synthase (NOS) and nitric oxide (NO) formation are associated with the pathogenesis of liver cirrhosis. NO-related stress alters the functions of biomolecules, especially proteins, probably as a result of nitration. The aim of this study was to assess the level of protein nitration and its correlation with the severity of the disease. Liver cirrhosis patients with different grades of severity (grades A, B, and C according to the Child–Pugh classification) were enrolled in this study. Nitroprotein content, arginine, citrulline, NO in terms of total nitrite, nitrosothiol (RSNO) and protein carbonyls were measured in blood. Immunohistochemical detection of nitroprotein was carried out in liver sections of cirrhosis patients. A significant elevation in the levels of serum and platelet arginine, arginase, citrulline, plasma, and platelet nitroproteins, RSNO, total nitrite, protein carbonyls and also a significant amount of nitrated proteins by immunohistochemical detection in tissue were observed in cirrhosis patients. The alterations were highly significant in grade C patients with bleeding complications when compared to those of grade B and A patients. In platelets, both cytosolic and cytoskeletal proteins were found to be nitrated significantly. The level of nitrite seems to have positive correlation with the level of nitroproteins in different grades of cirrhosis. The level of nitroproteins in plasma, platelets and liver tissue can be correlated with the severity of liver cirrhosis.     

Purification, characterization, cloning, and expression of the chicken liver ecto-ATP-diphosphohydrolase.

We previously demonstrated that the major ecto-nucleoside triphosphate phosphohydrolase in the chicken liver membranes is an ecto-ATP-diphosphohydrolase (ecto- ATPDase) [Caldwell, C., Davis, M.D. & Knowles, A.F. (1999) Arch. Biochem. Biophys. 362, 46-58]. Enzymatic properties of the liver membrane ecto-ATPDase are similar to those of the chicken oviduct ecto-ATPDase that we have previously purified and cloned. Using antibody developed against the latter, we have purified the chicken liver ecto-ATPDase to homogeneity. The purified enzyme is a glycoprotein with a molecular mass of 85 kDa and a specific activity of approximately 1000 U.mg protein-1. Although slightly larger than the 80-kDa oviduct enzyme, the two ecto-ATPDases are nearly identical with respect to their enzymatic properties and mass of the deglycosylated proteins. The primary sequence of the liver ecto-ATPDase deduced from its cDNA obtained by RT-PCR cloning also shows only minor differences from that of the oviduct ecto-ATPDase. Immunochemical staining demonstrates the distribution of the ecto-ATPDase in the bile canaliculi of the chicken liver. HeLa cells transfected with the chicken liver ecto-ATPDase cDNA express an ecto-nucleotidase activity with characteristics similar to the enzyme in its native membranes, most significant of these is stimulation of the ATPDase activity by detergents, which inhibits other members of the ecto- nucleoside triphosphate diphosphohydrolase (E-NTPDase) family. The stimulation of the expressed liver ecto-ATPDase by detergents indicates that this property is intrinsic to the enzyme protein, and cannot be attributed to the lipid environment of the native membranes. The molecular identification and expression of a liver ecto-ATPDase, reported here for the first time, will facilitate future investigations into the differences between structure and function of the different E-NTPDases, existence of liver ecto-ATPDase isoforms in different species, its alteration in pathogenic conditions, and its physiological function.     

Chlorpromazine, quinacrine, and verapamil as donor pretreatment in liver preservation, tested in the isolated perfused rat liver.

Rats were pretreated with a single iv dose of chlorpromazine (CPZ) 3 mg/kg, verapamil 1 mg/kg, or quinacrine 2 mg/kg. Livers were taken out and perfused with University of Wisconsin (UW) preservation solution and stored on ice for 48 h in the UW solution before reperfusion with erythrocyte-free and colloid-free Krebs-Hanseleit buffer at 38 degrees C in a nonrecirculating perfusion system for 2 h. CPZ- and quinacrine-pretreated livers produced significantly more bile than control livers and also released significantly less alanine aminotransferase into the perfusate at 30, 60, and 120 min of reperfusion. Aspartate aminotransferase levels were lower at 30 and 60 min of reperfusion for CPZ-pretreated livers but not at 120 min. The only difference between groups concerning lactate dehydrogenase (LDH) release into the perfusate was that CPZ decreased the amount of LDH released at 60 min. Total tissue water or tissue electrolyte content of the liver tissue at the end of the reperfusion did not differ between groups. In conclusion, verapamil was ineffective when given as single dose iv pretreatment to the liver donor but pretreatment with CPZ or quinacrine appeared to improve the function of the preserved liver.     

Imaging Plasmodium immunobiology in the liver,brain, and lung

Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as the brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite.     

Heterogeneity in the liver mitochondria of the tadpole, Rana catesbeiana

1. The heterogeneity of liver mitochondria of the tadpoles, Rana catesbeiana, undergoing metamorphosis was investigated by a combination of pulse-chase labeling of mitochondria with [methyl-3H]thymidine and centrifugation of mitochondria on a density gradient of metrizamide. 2. The liver mitochondria of tadpole at premetamorphic stage are separated into two populations with mean densities of 1.128 (M2) and 1.112 (M3). 3. At metamorphic stage a population with mean densities of 1.174 (M1) appears additionally. 4. The activity of mitochondria to take up [methyl-3H]thymidine in vivo is 2-3 times higher at metamorphic stage than at premetamorphic stage. 5. The M1 population has a prominently high activity to take up L-[4.5-3H]leucine in vitro and also a high specific activity of cytochrome c oxidase. 6. These findings suggest that the mitochondrial populations found are of alternate stages in the mitochondrial maturation.     

Cathepsin B, the lysosomal thiol proteinase of calf liver

Cathepsin B from calf liver was obtained by a method involving preparation of a lysosomal-mitochondrial pellet and treatment of this pellet with acetone. The material was extracted with an acid buffer, pH4.0, and then precipitated from the extract with acetone. The precipitate was dissolved in phosphate buffer, pH7.4, and subjected to gel filtration on Sephadex G-200 and G-100. The cathepsin B emerged in a range of molecular weight much lower than 50000 as a well-defined component. The purity of this material was checked by electrophoresis. To obtain maximum activity the enzyme had to be activated with a chelating agent and a reducing agent (i.e. EDTA and cysteine). A number of different substrates were used. The enzyme was active for the hydrolysis of both peptide bonds and ester bonds and had approximately equal reactivity in the two cases. The pH-dependence of the hydrolysis was the same with both substrates. The binding of the substrates was half-maximal at pH4.5 and at pH6.8. A thiol group occurred in the active centre but this group ought to have a much higher pK than that found in this enzyme.