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)

The blue-green alga Anacystis nidulans (strain L 1402-1) was grown at +37 degrees C in air (0.03 vol% CO2 and in air enriched with 3.0 vol% CO2. The effects of several inhibitors on the activity of aminotransferases, 14CO2 fixation and radioactive photosynthetic products of Anacystis were studied. No serine-pyruvate aminotransferase activity could be found in 10-2 M isonicotinyl hydrazide (INH); under the influence of this inhibitor aspartate and alanine aminotransferase were decreased about 49% respectively 17.6%. Serine-pyruvate and alanine aminotransferase activity decreased to more than 50% in 10-3 M glyoxalbisulfite. The obtained inhibitory effect of 10-4 M HPMS on serine-pyruvate aminotransferase (35%) was stronger than one the other aminotransferases. DCMU (5 x 10-6 M) inhibition on alanine aminotransferase activity was 83.7%. Under the influence of 10-3 M glyoxalbisulfite no 14C-labelled amino acids could be detected after 5 min photosynthesis; 14C-labelling of phosphoenolpyruvate, malate, phosphoglycolate and glycolic acid increased. Isonicotinyl hydrazide (10-2 M) caused in comparison to the control experiment a lower radioactivity in aspartate glutamate and phosphoenolpyruvate. The results are discussed with reference fo the operation of the glycolate pathway and a carboxylation reaction of phosphoenol-pyruvate in the blue-green alga Anacystis nidulans.
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PMID:[Activity of aminotransferases in the blue green alga Anacystis nidulans]. 13 84

In a retrospective study the following was found: Out of 111 patients suffering from tuberculosis and receiving a combined INH-therapy without Rifampicin 23% showed an increase of serum-transmainase activities, on the other hand out of 105 patients, treated with a combination including Rifampicin 74% did so. A pathological De Ritis ratio GOT/GPT was found in 31 among 59 comparable cases of Rifampicin-treated patients, and a pathological ratio GOT + GPT/AP in 22 among 37 cases before the transaminase-activities rose above normal. Development of a distinct toxic hepatic damage has to be anticipated in those cases, which show a De Ritis ratio below 0,5 or a GOT + GPT/AP ratio above 1,0 while transaminase-activity still is only slightly elevated. Liver biopsies taken from 10 patients showed no regular relation to the biochemical data.
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PMID:[Frequency, diagnosis, and course of hepatotoxic side effects of Rifampicin (author's transl)]. 99 24

Isoniazid (INH) is a selective inducer of cytochrome P-450 isozymes that are involved in the biotransformation of organohalogen anesthetics. It has been used to produce a rat model of halothane-associated hepatotoxicity that was linked to enhanced oxidative biotransformation of the anesthetic. Guinea pigs were pretreated with INH in order to potentiate halothane-induced hepatic necrosis and to study the oxidative pathway as a hepatotoxic mechanism in this species. The animals received either 12.5, 25.0 or 50.0 mg kg-1 INH i.p. for 7 days. Following halothane exposure, there were dose-dependent increases in plasma levels of the oxidative halothane metabolite, trifluoroacetic acid. These increases were associated with increases in 48 h plasma alanine aminotransferase (ALT) levels. When combined with halothane exposure, the two higher doses of INH killed the animals before planned termination. These deaths were not attributable to hepatic failure. Dividing the 25 mg kg-1 INH dose into twice daily injections of 12.5 mg kg-1 reduced deaths. INH pretreatment control animals exhibited occasional non-dose-dependent increases in ALT as well as the occurrence of fatty vacuolization of hepatocytes at the highest dose. Even though INH pretreatment enhanced oxidative halothane biotransformation and subsequent hepatotoxicity, sensitivity of guinea pigs to the deleterious actions of INH would contraindicate its use as a cytochrome P-450 induction agent.
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PMID:Isoniazid potentiation of a guinea pig model of halothane-associated hepatotoxicity. 238 Apr 77

The paper investigates the relationships between hydrophobic parameters and antituberculotic activity of 2-alkylthio-6-benzamidobenzothiazoles, tested on INH-resistant strain of Mycobacterium tuberculosis. In the group of compounds with linear alkyl substituents in position 2, the tuberculostatic effect is increasing with decrease of lipophility of alkyls. Branching of the alkyls strongly increases the activity. The hepatotoxicity of compounds under study was investigated by means of the activity of serum aminotransferases (ALT, AST) in Wistar type rats. The hepatotoxicity of compounds seemed to be smaller than that of the thiobenzamides.
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PMID:[Relation between chemical structure, antitubercular activity and hepatotoxicity of 2-alkylthio-6-benzamidobenzothiazoles]. 312 40

Both tuberculosis and hepatitis B are endemic in southeast Asia and are common among refugees to the United States from that region. Isoniazid, used for the prophylactic treatment of tuberculosis, is a potentially hepatotoxic drug. Carriers of the hepatitis B virus are likely to have some degree of liver damage due to their chronic infection. We hypothesized that prophylactic treatment of carriers with isoniazid would cause greater liver damage, as measured by serum alanine aminotransferase (ALT) levels, than would such therapy of noncarriers. Cross-sectional and longitudinal studies of the southeast Asian refugee population in Philadelphia failed to support this hypothesis. Isoniazid did not cause greater hepatotoxicity in hepatitis B carriers than in noncarriers. Although carriers had higher ALT levels than noncarriers, both groups experienced transient ALT elevations during the first 2 months of isoniazid prophylactic therapy. Therefore, we concluded that chronic infection with hepatitis B virus is not a contraindication to the prophylactic use of isoniazid.
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PMID:Isoniazid prophylaxis in hepatitis B carriers. 376 21

The incidence and degree of liver injury was prospectively evaluated in 44 children, ages between 4 months and 14 years (mean age, 4.5 years) treated for tuberculosis with 15 to 20 mg isoniazid/kg/day and 15 mg rifampin/kg/day (INH-RIF). None of the patients had hepatic dysfunction before initiation of treatment. Elevation of the serum alanine aminotransferase (ALT) concentration (greater than 100 units) occurred in 36 patients (82%). One patient with an increase in the ALT value had coincidental infection with hepatitis B. The incidence of hepatotoxicity did not correlate with the patients' age or sex. Fifteen of the 36 patients developed clinical hepatitis with jaundice. In 7 patients liver enlargement and prolongation of the prothrombin time were also observed. In all but one patient liver dysfunction was recognized 6 to 30 days (mean, 14 days) after start of treatment. Biochemical signs of hepatic injury in the 35 surviving patients regressed completely without alteration of the INH-RIF regimen in 22 patients. These facts suggest the possibility that hepatocellular damage may be due to the effect of tubercle bacilli products liberated in the liver after their destruction by antituberculous drugs. However, the high rate of hepatotoxic reactions warns that the dose of 10 mg INH/kg/day should not be exceeded when that drug is combined with RIF.
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PMID:Hepatotoxic reactions in children with severe tuberculosis treated with isoniazid-rifampin. 400 Sep 89

We report the case of a 28-year-old-prostitute from Thailand with HIV infection stage B2 associated with retroperitoneal lymph node tuberculosis. 6 days after the beginning of anti-tuberculous therapy (isoniazid, rifampicin, pyrazinamid and ethambutol) the temperature rose to 40.5 degrees C, diarrhea, vomiting, and tachycardia developed and systolic blood pressure fell to 80 mm Hg. Liver function tests revealed acute hepatic failure (ALT 800 IU/l rising to 1500; serum bilirubin 89 mumol/l rising to 238.0; alkaline phosphatase 199 IU/l; glucose 1.8 mmol/l; prothrombin time 20%). Isoniazid, rifampicin, and pyrazinamid were replaced by streptomycin and PAS. A few days after withdrawal the liver profile returned to normal. Hours after the reintroduction of rifampicin total body erythema, pruritus, vomiting and severe hypotension developed, requiring saline methylprednisolone and epinephrine administration. The next reexposure to intravenous rifampicin produced a rash and was rapidly discontinued. Liver function tests remained normal. Later mild adverse reactions to streptomycin and pyrazinamid occurred, two drugs which had been well tolerated before. Subsequently the diagnosis of adrenal insufficiency was established. After initiation of steroid replacement (50 mg prednisolone) the antituberculous therapy with isoniazid, pyrazinamid and ethambutol was well tolerated. We conclude that the shock in this HIV-infected patient was either due to severe anaphylaxis to rifampicin or acute adrenal insufficiency ensuing on this drug. The reversible fulminant acute hepatic failure represents either an adverse effect of antituberculous drugs, especially hepatotoxic interactions of drug combinations, or an ischemic liver injury during hypotension caused by anaphylaxis. The case illustrates the complex nature of side effects of antituberculous drugs in HIV patients and their aggravation by adrenal insufficiency.
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PMID:[Fulminant, rapidly reversible hepatitis and life-threatening anaphylaxis following rifampicin in an HIV-positive female patient with latent adrenal cortex insufficiency]. 864 39

The role of oxidative stress as a mechanism of hepatic injury caused by isoniazid (INH) was investigated in young growing rats. The interaction of moderate and severe degree of protein-energy malnutrition (PEM) was also investigated. Hepatic injury was produced by giving 50 mg/kg/day of INH for 2 weeks. Liver showed kupffer cell hyperplasia along with patchy sinusoidal congestion in hematoxylin (H) and eosin (E) staining. However, diffuse microglobules of oil red O' positive fat globules could be demonstrated in frozen sections stained with oil red O'. The concomitant elevation of serum ALT/AST added support to the histopathologic injury. Electronmicroscopic analysis revealed the proliferation of rough endoplasmic reticulum in INH-treated groups. The glutathione and related thiols were decreased significantly by INH both in blood and liver tissues, indicating a decrease in protective mechanism. Glutathione reductase activity was elevated concomitantly in both the tissues. A significant decrease in the activity of glutathione peroxidase and catalase is again indicative of diminished capacity to handle the disposal of hydrogen peroxide (H2O2) and lipid peroxides. All these alterations indicated that the damage to the liver cell could well be operating through the inefficient disposal of superoxides (O-2) and H2O2. A profound decrease in the protective mechanism further aggravated the picture in moderate and severe PEM, which was observed with INH alone.
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PMID:Study of oxidative stress in isoniazid-induced hepatic injury in young rats with and without protein-energy malnutrition. 902 73

Cytochrome P450 2E1 (P450 2E1) is active in both the detoxification and activation of small organic molecules. The effects of 2-(allylthio)pyrazine (2-AP) on P450 2E1-catalytic activity and the expression of rat hepatic P450 2E1 were examined. 2-AP competitively inhibited 4-nitrophenol hydroxylase activity in vitro (Ki, 12 microM). 2-AP treatment of rats (200 mg/kg/day, p.o., 1-3 days old) resulted in 20-30% decreases in the rates of P450 2E1-specific metabolic activities. Immunoblot analysis also revealed that hepatic microsomes isolated from 2-AP-treated rats showed substantial decreases in P450 2E1 level. 2-AP-suppressed isoniazid (INH)-inducible hepatic P450 2E1 levels, as shown by both metabolic activities and immunoblot analyses. Thus, 2-AP was effective in suppressing both constitutive and inducible P450 2E1 expression. Northern blot analysis showed that 2-AP transiently suppressed the hepatic P450 2E1 mRNA level, suggesting that suppression in P450 2E1 expression by 2-AP may be mediated in part by transcriptional inactivation. Hepatoprotective effects of 2-AP against toxicants were monitored in mice. 2-AP pretreatment prior to the administration of lethal doses of acetaminophen (AAP) or INH substantially reduced toxicant-induced mortality. Whereas serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were markedly elevated after AAP administration (i.e. 9-20-fold), 2-AP pretreatment of animals before AAP administration resulted in >95% decreases in elevated serum aminotransferase activities. 2-AP was also effective against CCl4-induced hepatotoxicity. Whereas CCl4 treatment caused 35-70-fold increases in aminotransferase activities, treatment of mice with 2-AP (>10 mg/kg) resulted in the blocking of CCl4-induced liver toxicity. The hepatoprotective effect of 2-AP was in part due to 2-AP-induced elevation of hepatic GSH levels. Whereas AAP or CCl4 treatment resulted in 70-80% reduction in hepatic GSH levels, pretreatment of mice with 2-AP caused a 40-210% elevation in hepatic GSH levels, as compared with either AAP or CCl4 alone. 2-AP pretreatment also reduced AAP- or CCl4-induced increases in lipid peroxidation in a dose-dependent manner. The results of these metabolic activities and of immunoblot and RNA blot analyses demonstrate that 2-AP is efficacious in suppressing constitutive and inducible P450 2E1 expression and effective in protecting against toxicant-induced liver toxicity.
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PMID:Inhibition of cytochrome P450 2E1 expression by 2-(allylthio)pyrazine, a potential chemoprotective agent: hepatoprotective effects. 906 29

Thirty six cases with multidrug-resistant tuberculosis were retrospectively studied to define the causes attributable to the emergence of multidrug-resistant M. tuberculosis. All these tuberculosis cases were microbiologically confirmed and resistant to at least isoniazid and rifampicin. Data analysis using matched-pair sampling methods (1:3) demonstrated that the followings are the significant risk factors for the emergence of multidrug-resistant tuberculosis; incompliance to treatment (Odds ratio 21.0: 95% CI 4.10-107.63), alcohol abuse (Odds ratio 15.0: 95% CI 2.34-96.1) and the history of previous treatment (Odds ratio 5.0: 95% CI 2.04-12.21), while diabetes mellitus is not statistically significant. The incompliance to treatment which is primarily thought to be patient's responsibility results in non-optimal administration of antituberculous agents, leading to the multidrug-resistant tuberculosis. Other factors that may have contributed to the emergence of resistance included the unnecessary change of regimen before completion of chemotherapy. This is patient-unrelated situation where responsibility lies in the medical side. A clinical case presented here is an example. In this case RFP was replaced with ethambutol 3-months after the initiation of regimen including SM, INH and RFP because of abnormal elevation of GOT and GPT without any supporting evidence that RFP was causative. The readministration of RFP after 1-year cessation did not induce liver dysfunction, while the drug resistance was observed not only to RFP but also to INH. This case suggests unnecessary interruption of RFP could lead to the emergence of resistance to INH as well as RFP. One known mechanism of drug resistance is random mutation and the selection by drugs administered during the course of chemotherapy. The cases with advanced cavitary lesions would have a higher probability of the occurrence of mutation. The more the number of mutant bacilli, the higher the probability of emergence of multidrug resistance. Those cases in which longer period of time is needed for the negative conversion of M. tuberculosis should be treated with potent chemotherapy regimens under the intense supervision. Since both INH and RFP are the most potent among currently available antituberculous agents. It is crucial to preserve the potency of these essential agents before novel antituberculous are developed.
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PMID:[Attributable factors to the emergence of multidrug-resistant Mycobacterium tuberculosis based on the observation of consecutive drug resistance test results]. 973 79


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