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

---

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

TT virus (TTV) is a newly discovered transfusion-transmissible DNA virus, which may cause posttransfusion hepatitis. The virus was detected in 12% of Japanese blood donors. The aim of the study is to investigate the prevalence and clinical influence of TTV in bone marrow transplant (BMT) recipients. Sera from 25 BMT recipients obtained 6 to 12 weeks after the transplant were examined for TTV-DNA by the seminested polymerase chain reaction. Serial samples were additionally analyzed in patients with TTV-DNA. Fifteen of 25 recipients (60%) were positive for TTV-DNA after transplant, whereas it was detected in only two of 20 BMT donors (10%). In patients positive for TTV-DNA before BMT, the amount of TTV-DNA decreased to an undetectable level during the myelosuppressed period after BMT. We also found that there was a novel group of TTV, G3, classified by the nucleotide sequences. The median peak alanine aminotransferase (ALT) levels were 135.0 IU/L and 116.5 IU/L (normal range, 4 to 36 IU/L) in TTV-positive and TTV-negative recipients, respectively. In one of the seven TTV-positive patients who developed hepatic injury (ALT > 150 IU/L), a serial change in the serum TTV titer showed a good correlation with the ALT level. We concluded that (1) the prevalence of TTV is high in BMT recipients, (2) TTV might be replicated mainly in hematopoietic cells, (3) transfusion-transmitted TTV may cause persistent infection, (4) a novel genetic group of TTV, G3, was discovered, and (5) TTV does not seem to frequently cause hepatic injury, although one patient was strongly suggested to have TTV-induced hepatitis.
...
PMID:TT virus in bone marrow transplant recipients. 1019 26

A novel virus, TT virus (TTV), recently discovered by Okamoto et al. in the serum of a patient with posttransfusion hepatitis, is thought to be one of the causative agents of blood-borne acute hepatitis. The association of this virus with acute sporadic hepatitis was evaluated. TTV DNA was detected in 4 (4.9%) of 81 cases of acute hepatitis A, in 5 (16.7%) of 30 cases of acute hepatitis B, in 1 (25.0%) of 4 cases of acute hepatitis C, in 1 (9.1%) of 9 cases of cytomegalovirus and Eppstein-Barr infection, and in 8 (13.6%) of 59 cases of acute hepatitis of unknown etiology. These positive rates of TTV in various etiologies did not differ significantly amongst each other, and were similar to those of healthy volunteers, i.e. 12.0% (12/100). The comparison of levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, hepaplastin test and prothrombin time between TT virus-positive and -negative patients did not show any differences. This indicates that TTV is neither a main causative agent of acute sporadic hepatitis of unknown etiology, nor does it affect the clinical features of acute hepatitis with already known etiology.
...
PMID:TT virus (TTV) is not associated with acute sporadic hepatitis. 1021 44

TT virus (TTV), a novel DNA virus, has been reported in non-A to non-G posttransfusion hepatitis patients. Among 61 Japanese patients with liver diseases of non-B and non-C etiology, TTV DNA was detected in 15(25%) patients. The N22 region of TTV was sequenced and compared with the published sequence. Four genetic groups corresponding to G1a, G1b, G2 and G4 were formed. TTV was detected persistently regardless of its genotype/subtype. However, G2 and G4 contained 10 to 100 folds lower in titer than G1. Co-existing multiple mutants and subtypes were identified in one case. Since changes of TTV DNA titer and appearance of deduced amino acid substitution was not linked to ALT levels, the association of TTV to chronic liver diseases seemed low.
...
PMID:[The association of TTV genetic variant with liver disease]. 1039 Sep 78

A novel single stranded DNA virus, TT virus, associated with posttransfusion hepatitis was identified. The impact of the virus on development of chronic liver diseases and the susceptibility of the virus to interferon therapy has not been investigated. We retrospectively analyzed blood samples from 16 patients infected with both hepatitis C virus and TT virus who were treated by interferon. TT virus DNA was detected by nested polymerase chain reaction before, during and after interferon. Eight of these 16 patients became negative for TT virus DNA after such therapy but the virus re-appeared in one patient after cessation of therapy. All nine patients in whom interferon eliminated HCV exhibited normalization of alanine aminotransferase activity irrespective of persistence of TTV. In contrast, five of the seven patients who showed persistence of HCV after interferon had high levels of alanine aminotransferase (P = 0.034). These results suggest that TTV is sensitive to interferon and eradicated in a half of treated patients, but persists without liver injury for a long period in some patients.
...
PMID:[Susceptibility of TT virus to interferon therapy]. 1039 Oct 5

A novel DNA virus, TT virus (TTV), was identified in a Japanese patient with posttransfusion hepatitis. The epidemiology and etiological role of this virus have not been elucidated. We investigated the epidemiology of TTV infection in hepatitis C virus (HCV) high endemic and low endemic areas, R town and M town, respectively. The seroprevalence, potential risk factors, and laboratory features of TTV in relation to those of HCV were analyzed. TTV DNA was detected using a seminested polymerase chain reaction and the TTV genotypes were determined by a direct sequencing method. TTV DNA was detected in 16.1% of the subjects in R town and 17.5% of those in M town. The TTV DNA positivity rates of the 2 areas did not differ significantly. A history of blood transfusion was not a specific risk factor for TTV infection. The mean serum alanine aminotransferase (ALT) level of the anti-HCV-positive subjects was significantly higher than that of the TTV DNA-positive subjects, most of whom had normal ALT levels. The TTV genotype distributions of these 2 distinct areas differed. These results suggest that TTV infection is widespread with a geographical genotypic distribution independent of HCV infection and that the ALT abnormalities are not attributable to TTV but to HCV infection in the general population.
...
PMID:Relationship of TT virus infection with prevalence of hepatitis C virus infection and elevated alanine aminotransferase levels. 1044 18

Although TT virus (TTV) was isolated from a cryptogenic posttransfusion hepatitis patient, its pathogenic role remains unclear. It has been reported that the majority of the healthy population is infected with TTV. To elucidate the differences between TTV infection in patients with liver diseases and TTV infection in the healthy population, a quantification system was developed. TTV DNA was quantified by a real-time detection PCR (RTD-PCR) assay on an ABI Prism 7700 sequence detector. With this system, TTV DNA was quantified in 78 hepatitis C virus (HCV)-infected patients (63 with elevated serum alanine aminotransferase [ALT] levels and 15 with normal ALT levels) and in 70 voluntary blood donors (BDs). The quantification range was 2.08 to 7.35 log copies/ml. The intra-assay and interassay coefficients of variation were 0.37 to 6.33% and 0.60 to 7.07%, respectively. The mean serum TTV DNA levels in the HCV-infected patients with both elevated and normal ALT levels and BDs were 3.69 +/- 0.89, 3.45 +/- 0.76, and 3.45 +/- 0.67 log copies/ml, respectively. Comparison of the serum TTV DNA levels among the HCV-infected patients revealed that they were not related to the serum ALT and HCV core protein levels or to the histopathological score on liver biopsy. This study showed that (i) the RTD-PCR assay for the detection of TTV was accurate and had a high degree of sensitivity, (ii) the mean serum TTV DNA level was similar among HCV-infected patients, irrespective of their ALT level, and also among BDs, and (iii) a high serum TTV DNA level does not affect the serum ALT and HCV levels or liver damage in HCV-infected patients.
...
PMID:Development of a TT virus DNA quantification system using real-time detection PCR. 1061 70

TT virus (TTV) has been identified in patients with posttransfusion hepatitis of unknown etiology and is thought to be a new hepatitis virus. We determined the extent of TTV infection in the Japanese general population and the relationship between TTV DNA genotype and liver damage. In 1998, we tested 847 serum samples for TTV. TTV DNA was assayed by a nested polymerase chain reaction and classified into three different genotypes and eight subtypes. TTV DNA was detected in 25.3% and 32.4% of the inhabitants of the two areas studied, respectively. The genotype distribution was similar in both areas. G1, G2, and G3 were 60%, 20%, and 5%, respectively. Of the 20 subjects with TTV DNA alone and elevated serum ALT levels, 18 were G1, one was G2, and one was G3. TTV infection is endemic in the Japanese general population studied. The main TTV genotype, G1, may be related to the ensuing liver damage.
...
PMID:Seroepidemiology of TT virus infection and relationship between genotype and liver damage. 1121 42

TT virus (TTV) has been reported to occur in association with elevated alanine aminotransferase (ALT) levels in patients with posttransfusion hepatitis of unknown etiology. We examined whether the presence, change of DNA titer, or variation in sequence of this virus is associated with acute or chronic liver dysfunction in Japanese. We detected TTV by polymerase chain reaction (PCR) using primers generated from the conserved region of the TTV genome. Direct DNA sequencing of the original N22 region was used to characterize TTV isolates. We detected TTV DNA in 15 (25%) of 60 patients with liver dysfunction. Variants recovered from infected patients formed four genotypes/subtypes, corresponding to G1a, G1b, G2, and G4. Although TTV DNA titers in patients with G2 and G4 were lower than those with G1, TTV was consistently detected regardless of genotype/subtype. TTV infection continued for at least 1 year after normalization of ALT level in patients with acute liver dysfunction. Changes in DNA titer, substitutions of deduced amino acids, and variety of quasispecies of TTV were detected during the observation period, but no significant fluctuation in ALT level was found. We conclude that persistent infection, changes in DNA titer, and variation in sequence of this novel virus are not significantly related to hepatic disorders.
...
PMID:Changes of DNA titer and sequence variance of TT virus in hepatic disorders. 1125 4

TTV, the transfusion transmissible hepatitis virus infects mainly patients at risk for parenteral exposure and hence, prone to develop chronic liver disease, as well as healthy populations worldwide. Most TTV infections appear to occur parenterally, with viremia detected frequently in blood donors and blood products. The substantial proportion of asymptomatic individuals never exposed to blood-borne agents, and its high prevalence among healthy subjects implicates the fecal-oral route as another potential for transmission. According to the TTV DNA levels detected in liver tissue, it apparently replicates in hepatocytes, and TTV DNA is present in sera of patients with posttransfusion hepatitis of unknown etiology closely correlated with ALT levels. However, TTV initiating the development of chronic liver disease or causing posttransfusion hepatitis could not be confirmed, as most patients positive for TTV DNA remain asymptomatic and those progressing towards chronic liver disease are invariably coinfected with either the hepatitis B or C virus. Also, TTV coinfection does not aggravate the symptoms associated with hepatitis B or C. Similarly, it does not cause posthepatitis aplastic anemia, and high-risk patients can immunologically clear the viral DNA. In conclusion, being widely distributed and apparently nonpathogenic, TTV might represent an opportunistic but innocent virus reminiscent of hepatitis G virus, with a negligible role in the etiology of chronic liver disease.
...
PMID:Transfusion transmissible virus TTV and its putative role in the etiology of liver disease. 1126 79

TT virus (TTV) is a newly isolated DNA virus from the serum of a patient with posttransfusion hepatitis of unknown etiology in 1997. To evaluate the clinical and molecular characteristics of TT virus (TTV) in a hepatitis C virus (HCV) and B (HBV) hyperendemic area (Masago), 200 residents were enrolled in the study. The sera were tested for alanine aminotransferase (ALT), HCV RNA and GB virus C/Hepatitis G virus (HGV) RNA, TTV DNA, HBsAg, anti-HCV and antibodies to HGV E2-protein (anti-E2). TTV DNA was positive in 99 of the 200 sera with a prevalence rate of 49.5%. The prevalence of HBsAg, anti-HCV, HCV RNA, HGV RNA, anti-E2 and HGV exposure (defined as positive for serum HGV RNA and/or anti-E2) was 38.9%, 69.5%, 64.5%, 17.0%, 25.5% and 39.5%, respectively. Neither clinical nor virological factors were associated with TTV viremia. The rate of ALT abnormality was significantly elevated in HCV RNA-positive (34.9%) than -negative (7.0%) residents (p < 0.001). HCV viremia was the only factor significantly associated with ALT elevation by multiple logistic regression (odds ratio: 6.96; 95% C.I.: 2.60-18.7). We concluded that in this HCV/HBV hyperendemic area, the prevalence of TTV DNA was high. No significant clinical factor was observed to be associated with TTV infection. TTV infection is not related to abnormal ALT levels and ALT abnormality was mainly attributable to HCV but not TTV, HBV or HGV infection.
...
PMID:The epidemiology of TT virus (TTV) infection in a hepatitis C and B virus hyperendemic area of southern Taiwan. 1127 96


<< Previous 1 2 3 4 5 6 Next >>

---