Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nonenzymatic glycosylation and cross-linking of proteins by glucose contributes to an age-associated increase in vascular and myocardial stiffness. Some recently sythesized thiazolium compounds selectively break these protein cross-links, reducing collagen stiffness. We investigated the effects of 3-phenacyl-4,5-dimethylthiazolium chloride (ALT-711) on arterial and left ventricular (LV) properties and their coupling in old, healthy, nondiabetic Macaca mulatta primates (age 21 +/- 3.6 years). Serial measurements of arterial stiffness indices [i.e., aortic pulse wave velocity (PWV) and augmentation (AGI) of carotid arterial pressure waveform] as well as echocardiographic determinations of LV structure and function were made before and for 39 weeks after 11 intramuscular injections of ALT-711 at 1.0 mg/kg body weight every other day. Heart rate, brachial blood pressure, and body weight were unchanged by the drug. PWV and AGI decreased to a nadir at 6 weeks [PWV to 74.2 +/- 4.4% of baseline (B), P = 0.007; AGI to 41 +/- 7.3% of B, P = 0.046], and thereafter gradually returned to baseline. Concomitant increases in LV end diastolic diameter to 116.7 +/- 2.7% of B, P = 0.02; stroke volume index (SV(index)) to 173.1 +/- 40.1% of B, P = 0.01; and systolic fractional shortening to 180 +/- 29.7% of B, P = 0.01 occurred after drug treatment. The LV end systolic pressure/SV(index), an estimate of total LV vascular load, decreased to 60 +/- 12.1% of B (P = 0.02). The LV end systolic diameter/SV(index), an estimate of arterio-ventricular coupling, was improved (decreased to 54.3 +/- 11% of B, P < 0.002). Thus, in healthy older primates without diabetes, ALT-711 improved both arterial and ventricular function and optimized ventriculo-vascular coupling. This previously unidentified cross-link breaker may be an effective pharmacological therapy to improve impaired cardiovascular function that occurs in the context of heart failure associated with aging, diabetes, or hypertension, conditions in which arterial and ventricular stiffness are increased.
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PMID:A cross-link breaker has sustained effects on arterial and ventricular properties in older rhesus monkeys. 1115 13

Hepatitis C virus (HCV) infection is a major problem associated with hemodialysis. The extent of liver damage in hemodialysis patients with chronic HCV infection has not been thoroughly documented. The aim of this study was to evaluate liver damage of hemodialysis patients infected with HCV. A total of 233 hemodialysis patients were categorized into two groups at entry: group X, 80 positive for serum HCV RNA, and group Y, 153 negative for serum HCV RNA. All were tested for serum alanine aminotransferase (ALT) serially from 1989 to 1998, and serum hyaluronic acid (HA), serum type-IV collagen (IV-C), platelet counts, and ultrasonographic examination of the liver was done in 1998. In group X, 61.3% had continuously abnormal ALT levels for over six months followed by normal ALT levels. Of the group X patients, 11.3% had abnormal ALT levels in 1998, and in three, hepatocellular carcinoma occurred. Mean HA and IV-C levels in group X (648.8 and 188.7 ng/ml, respectively) were significantly higher than in group Y (213.1 and 165.5 ng/ml, respectively) (P < 0.05). Ultrasonographic findings significantly correlated with serum HA level and platelet counts and showed significantly more abnormalities in group X than in group Y (P < 0.05). From these findings, a combined examination with ultrasonography and serum fibrogenesis markers is useful for detection of liver damage in hemodialysis patients with HCV viremia.
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PMID:Liver damage in hemodialysis patients with hepatitis C virus viremia: a prospective 10-year study. 1121 43

Over 90% of intravenous heroin addicts (IVHAs) carry the hepatitis C virus (HCV). The other hepatitis viruses, A, B, D, and G are relatively unimportant in IVHAs compared to HCV although active hepatitis B may demonstrate a chronic, degenerative course identical to that of HCV. The clinical course of HCV and active hepatitis B may span three or more decades. It is helpful to classify patients as in the active, cirrhosis, or liver failure stages. Only in the active, early stage are the liver enzymes, ALT and AST, likely to be elevated. It is this stage that will most likely respond to antiviral therapy. HCV has so many extra-hepatic manifestations including immune suppression, collagen diseases, and possibly lymphoma and leukemia that the disease is best termed HCV syndrome rather than simple hepatitis.
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PMID:Hepatitis C, B, D, and A: contrasting features and liver function abnormalities in heroin addicts. 1128 27

1. In the present study, we investigated the preventive effects of pirfenidone (PFD), an antifibrotic agent, on experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. 2. Treatment with DMN caused a significant decrease in bodyweight and liver weight. Oral PFD (500 mg/kg daily for 4 weeks) essentially prevented this DMN-induced loss in bodyweight and tended to suppress the loss in liver weight. There were no significant differences in liver weight and serum L-alanine aminotransferase levels between PFD-treated and -untreated groups. Pirfenidone has no major side effects in vivo. 3. Pirfenidone suppressed the induction of hepatic fibrosis determined by histological evaluation and reduced hepatic hydroxyproline levels. Expression of mRNA for type I collagen and transforming growth factor-beta in the liver was also suppressed by PFD treatment. 4. Because hepatic stellate cells (HSC) are the major cellular source of extracellular matrix in hepatic fibrosis, we examined the effects of PFD on type I collagen production in vitro using rat primary HSC cultures. Pirfenidone inhibited collagen production in HSC culture in a dose-dependent manner. 5. These results demonstrate that the inhibitory effects of PFD against hepatic fibrosis may be due, at least in part, to blockade of collagen production by HSC and suggest that PFD may be potentially useful in the prevention of the development of hepatic fibrosis.
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PMID:Pirfenidone inhibits dimethylnitrosamine-induced hepatic fibrosis in rats. 1142 18

Vascular and/or myocardial stiffness is a major problem in ageing, diabetes, hypertension and heart failure. The development of the stiffness is partly due to the formation of glucose-dependent cross-links in the collagen. ALT-711 cleaves these cross-links. In aged-rhesus monkeys, ALT-711 decreases vascular stiffness and this effect is reversible. ALT-711 also decreases myocardial stiffness in the monkeys but this effect is not reversible in 39 weeks. ALT-711 has potential in the treatment of the stiffness associated with diabetes, hypertension and heart failure.
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PMID:ALT-711 decreases cardiovascular stiffness and has potential in diabetes, hypertension and heart failure. 1142 1

The similarities between clinical features of erythema infectiosum and collagen disease or other viral infections prompted us to investigate clinical manifestations and laboratory data of parvovirus B19 (B19) infection in adults. We diagnosed all five patients as acute B19 infection by antibody assays. The age of patients ranged from 18 to 39 years old (mean 29), and all patients were female. All five patients showed high fever, arthralgia and edema of the extremities. Four of the five patients showed skin rash of the extremities or cheeks. Two patients were diagnosed as erythema infectiosum by family physicians before coming to us. The three remaining patients were suspected to be systemic lupus erythematosus, adult Still disease or rubella indivisually and referred to our hospital. A-27-old female (case 5) visited our hospital because of polyarthralgia and butterfly rash on her face. A test for antinuclear antibodies (ANA) was positive at a dilution of 1:320. Rheumatoid factor (RF) was also detected by latex fixation test. Her AST was 51 IU/L, ALT 68 IU/L and LDH 568 IU/L. Her symptoms persisted for 3 weeks and hepatic dysfunction recovered within 3 weeks. Five months later. ANA was negative at the dilution of less than 1:40. We suggest that the similarities between some symptoms of B19 infection and clinical and serological manifestation of collagen diseases merit closer attention.
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PMID:[Five cases of erythema infectiosum in adults]. 1149 63

Kupffer cells are involved in the pathogenesis of chemically mediated liver injury through release of biologically active mediators that promote the pathogenic process. The purpose of this study was to elucidate specific biochemical and molecular changes occurring in Kupffer cells throughout a time course of carbon tetrachloride (CCl(4))-mediated liver injury and fibrosis. Rats were administered 1 ml/kg of CCl(4) (10% v/v olive oil) twice weekly for up to 6 weeks. Plasma alanine aminotransferase values and hematoxylin-and-eosin- and trichrome-stained liver sections indicated minor liver damage at 2 weeks followed by increased damage and collagen deposition by 4 and 6 weeks. Additionally, mRNA levels in Kupffer cells isolated from CCl(4)-treated rats demonstrated significant increases in tumor necrosis factor alpha (TNF alpha); tumor growth factor beta; interleukin-6 (IL-6); interleukin 1 beta; cyclooxygenase 2; CD14, and I kappa B alpha transcripts after 2 and 4 weeks of treatment. However, the expression of these genes at 6 weeks was similar to that of controls. Increased gene expression of cytokines in Kupffer cells isolated from CCl(4)-treated rats was accompanied by increases in protein production of TNF alpha, IL-6, IL-1 beta, and interleukin 10 following lipopolysaccharide stimulation. Further, liver sections stained for ED2-positive cells demonstrated an increase in the number of resident macrophages at 2 and 4 weeks with a slight decrease in ED2-positive cells by week 6 but still significantly more than control. Analysis of reduced glutathione (GSH) and oxidized glutathione (GSSG) indicated that Kupffer cells from CCl(4)-treated animals exhibited a 50% decrease in GSH at 2 and 4 weeks, whereas no significant changes were observed for GSSG. In conclusion, these data implicate Kupffer cells as a critical mediator of the inflammatory and fibrogenic responses during CCl(4)-mediated liver damage and provide new insight into the temporal molecular and biochemical changes associated with the ability of these resident macrophages to modulate liver injury.
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PMID:Activation of Kupffer cells during the course of carbon tetrachloride-induced liver injury and fibrosis in rats. 1173 48

Troglitazone is a peroxisome proliferator-activated receptor-gamma agonist that has been shown to halt mesangium expansion in experimental models of type 2 diabetes mellitus and to act directly on rat mesangial cells. Because glutamine serves as the precursor for cellular biosynthetic processes, we asked whether troglitazone would inhibit mesangial cell glutamine metabolism under these conditions. Confluent monolayers of rat mesangial cells were incubated in RPMI medium in the presence of troglitazone or vehicle (DMSO). Troglitazone effected a dose-dependent reduction in glutamine utilization and in alanine formation, associated with a decrease in monolayer collagen-glycosaminoglycan content. Despite the reduced glutamine uptake, ammonium formation did not decrease, consistent with increased glutamate flux through the deamination pathway. Assayable activity of the alanine aminotransferase decreased by 63%, whereas assayable glutamate dehydrogenase remained unchanged. In control monolayers, the sum of ammonium plus alanine plus glutamate nitrogen released accounted for <75% of the glutamine nitrogen uptake. In troglitazone-treated monolayers, all of the glutamine nitrogen taken up could be accounted for as ammonium nitrogen released into the medium. These results are consonant with troglitazone reducing glutamine metabolism and specifically the transamination pathway in rat mesangial cells associated with a reduction in collagen-glycosaminoglycan content.
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PMID:Troglitazone inhibits glutamine metabolism in rat mesangial cells. 1173 5

AIM:To investigate effect of losartan, an AT1 receptor antagonist, on hepatic fibrosis induced by CCl(4); and to determine whether or not AT1 receptors are expressed on hepatic stellate cells. METHODS AND RESULTS:Fifty male Sprague-Dawley rats, weighing (180 plus minus20)g, were randomized into five groups (control group, model group, and three losartan treated groups), in which all rats were given the subcutaneous injection of 40% CCl(4)(every 3 days for 6 weeks) except for rats of control group. Rats of losartan-treated groups were treated with losartan (20 mg/kg, 10 mg/kg, 5 mg/kg, daily gavage). After 6 weeks liver tissue and serum samples of all rats were examined. Serum hyaluronic acid (HA), procollagen type III (PC III) were detected by radioimmunoassays. van Giesion collagen staining was used to evaluate the extracellular matrix of rats with liver fibrosis. The expression of AT1 receptors, transforming growth factor-beta (TGF-beta), and alpha-smooth muscle actinalpha-SMA) in liver tissue were determined by immunohistochemical techniques. Compared with model group, serum ALT and AST of losartan-treated groups were significantly reduced (italic>t = 4.20,P < 0.01 and italic>t = 4.57,P < 0.01). Serum HA and PC III also had significant differences (italic>t = 3.53,P<0.01 and t=2.20, P<0.05). The degree of fibrosis was improved by losartan and correlated with the expressions of AT1 receptors, TGF-beta, and alpha-SMA in liver tissue.CONCLUSION:AT1 receptor antagonist, losartan, could limit the progression of the hepatic fibrosis induced by CCl(4). The mechanism may be related to the decrease in the expression of AT1 receptors and TGF-beta, ameliorating the injury of hepatocytes; activation of local renin-angiotensin system might relate to hepatic fibrosis; and during progression of fibrosis, activated hepatic stellate cells might express AT1 receptors.
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PMID:Effects of AT1 receptor antagonist, losartan, on rat hepatic fibrosis induced by CCl(4). 1181 43

Hydrophobic bile acids lead to generation of oxygen free radicals in mitochondria. Accordingly, this study investigated if gene delivery of superoxide dismutase (SOD) would reduce hepatic injury caused by experimental cholestasis. Rats were given adenovirus (Ad; 3 x 10(9) p.f.u., i.v.) carrying the bacterial control gene lacZ, mitochondrial Mn-SOD or cytosolic Cu/Zn-SOD genes 3 days before bile duct ligation. Both Mn- and Cu/Zn-SOD activity was increased in the liver about four-fold 3 days after viral infection. Serum alanine transaminase increased to about 710 U/l after bile duct ligation, which was blunted by about 70% in rats receiving Ad-Mn-SOD, but by only 30% in rats receiving Ad-Cu/Zn-SOD. Bile duct ligation caused focal necrosis, apoptosis and fibrosis in the liver and increased collagen alpha1 mRNA about 20-fold. These effects were reduced significantly by Ad-Mn-SOD, but not by Ad-Cu/Zn-SOD. In addition, bile duct ligation increased 4-hydroxynonenal, a product of lipid peroxidation, activated NF-kappaB and increased synthesis of TNF(alpha) and TGF-beta. These effects were also blunted significantly by Ad-Mn-SOD, but not by Ad-Cu/Zn-SOD. Taken together, it is concluded that cholestasis causes liver injury by mechanisms involving mitochondrial oxidative stress. Gene delivery of mitochondrial Mn-SOD blocks formation of oxygen radicals and production of toxic cytokines thereby minimizing liver injury caused by cholestasis.
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PMID:Viral gene delivery of superoxide dismutase attenuates experimental cholestasis-induced liver fibrosis in the rat. 1185 21


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