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:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We retrospectively investigated the clinical and histopathologic features of hospitalized patients infected with human immunodeficiency virus who had symptomatic lactic acidosis syndrome at a university teaching hospital during 1995-2000. Twelve patients were identified, 11 during 1998-2000; of these, 5 died with rapid progression to otherwise unexplained multiple-organ failure. All had extensive prior exposure to nucleoside analog reverse-transcriptase inhibitors (NRTIs). At presentation, the most commonly identified NRTI component of antiretroviral regimens was stavudine plus didanosine. Eleven patients presented with abdominal pain, nausea, and/or emesis. Eight patients had prior acute weight loss (mean [+/-SD], 12+/-5.3 kg). Median venous plasma lactate levels were > or =2-fold greater than the upper limit of normal (2.1 mmol/L). Serum transaminase levels were near normal limits at presentation. Histopathologic studies confirmed hepatic macrovesicular and microvesicular steatosis in 6 patients. Concurrent chemical pancreatitis was identified in 6 patients. The increasing number of cases identified during the study period suggests that physicians better recognize symptomatic lactic acidosis and/or that cumulative NRTI exposure may increase the risk for this syndrome.
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PMID:Symptomatic lactic acidosis in hospitalized antiretroviral-treated patients with human immunodeficiency virus infection: a report of 12 cases. 1169 4

Expanded access programs (EAPs) provide medication to patients with life-threatening, treatment-refractory illnesses before regulatory approval and allow the acquisition of safety information. A 2-part, multisite EAP to evaluate abacavir, a carbocyclic nucleoside reverse-transcriptase inhibitor for use in combination antiretroviral therapy, was conducted. The EAP involved >13,000 adults infected with human immunodeficiency virus type 1 (HIV-1) who no longer responded to commercially available treatment regimens. Part A (open-label trials) examined the efficacy, safety, and tolerance of abacavir, and part B (provision of abacavir through expanded access) assessed only the occurrence of serious adverse events. By month 2 of abacavir-containing treatment, plasma HIV-1 RNA levels decreased by > or =0.5 log(10) in 31.4% of patients, and 5.6% of the patients had HIV-1 RNA levels decrease to <400 copies/mL. Drug-related serious adverse events were reported by 7.7% of patients, the most common of which were nausea, skin rash, diarrhea, malaise or fatigue, and fever. Approximately 4.6% of patients experienced a hypersensitivity reaction that was possibly drug related. Overall, the types and incidences of adverse events reported in the abacavir EAP were similar to those reported in phase 2 and 3 clinical trials evaluating abacavir.
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PMID:Abacavir expanded access program for adult patients infected with human immunodeficiency virus type 1. 1179 83

Tipranavir (TPV) is a non-peptidic protease inhibitor belonging to the class of 4-hydroxy-5,6-dihydro-2-pyrones, which exhibits potent and specific activity against HIV type I (HIV-1) and 2 (HIV-2). Clinically effective plasma levels of TPV are achieved by concomitant administration of ritonavir (RTV). Therefore, TPV has been coadministered with RTV in clinical trials. TPV has demonstrated antiviral activity against HIV-1 isolates that are resistant to reverse-transcriptase and selected peptidic protease inhibitors. Therefore, TPV is emerging as one of the newer drugs in the armamentarium against HIV-1 in patients demonstrating multi-drug resistance. TPV administered orally to humans exhibits linear pharmacokinetics at doses of 100 - 2000 mg. Steady-state plasma levels are attained within 7 days of initiating multiple dosing. The half-life of the drug is approximately 6 h at steady-state. The plasma concentration is lower with repeated dosing than predicted from single-dose studies due to induction of the cytochrome p450 3A4 isoform of the liver microsomal enzyme system. Phase II clinical trials have shown that the administration of TPV and RTV in combination is safe and generally well-tolerated in HIV-1-infected adults. Phase III trials are underway to compare the efficacy of this drug versus other antiretroviral regimens. Gastrointestinal toxicity has been described with TPV, the most frequently reported side effects being diarrhoea, nausea, vomiting and abdominal pain. There is no known evidence of teratogenicity or effect on fertility. TPV dosed twice-daily, in the range of 500 - 1250 mg and combined with 100 - 200 mg of RTV has been shown to substantially and durably reduce viral load in HIV-1-infected drug-naive and experienced patients.
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PMID:Tipranavir: a novel non-peptidic protease inhibitor for the treatment of HIV infection. 1458 57

Capravirine is a nonnucleoside reverse-transcriptase inhibitor (NNRTI) with a unique resistance profile. Although single mutations allow resistance to established NNRTIs, human immunodeficiency virus (HIV)-1 must undergo multiple mutations to achieve resistance to capravirine. In the present phase 1 study, capravirine was administered orally for up to 28 days to 55 HIV-1-infected individuals with CD4+ T lymphocyte counts of 50-500 cells/microL. The most frequent adverse events were diarrhea (5%) and nausea (4%), with no drug-related rashes observed. The day 15 median (mean) HIV-1 load decreased by 1.34 (1.45) log(10) copies/mL in the patients receiving 25 mg/kg/day. Capravirine demonstrated potent antiviral activity, even in antiretroviral-experienced patients.
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PMID:Capravirine, a nonnucleoside reverse-transcriptase inhibitor in patients infected with HIV-1: a phase 1 study. 1552 60

Nucleoside reverse-transcriptase inhibitors (NRTIs) have been associated with functional and structural mitochondrial abnormalities, leading to several adverse events, such as increased serum lactic acid levels and lactic acidosis. Mild-to-moderate, asymptomatic hyperlactataemia has been frequently reported in human immunodeficiency virus (HIV)-infected patients treated with NRTIs, with an estimated prevalence between 15% and 35%. On the contrary, symptomatic, severe hyperlactataemia and lactic acidosis are less common, with an incidence ranging from 1.7 to 25.2 cases per 1000 person-years of antiretroviral treatment, and are associated with a remarkable mortality rate, which varies from 30% to 60% in different studies. The clinical presentation of lactic acid syndrome is non-specific and includes asthenia, malaise, nausea, vomiting, abdominal pain, weight loss, tachypnoea, dyspnoea, liver steatosis and increased transaminase levels, and risk factors include previous or concurrent therapy with stavudine or didanosine. Management of symptomatic lactic acid alterations involves NRTI-therapy interruption and supportive care, while natural history of hyperlactataemia is still unknown, and it is uncertain whether asymptomatic patients with increased lactate concentrations are at increased risk of developing lactic acidosis.
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PMID:Hyperlactataemia and lactic acidosis in HIV-infected patients receiving antiretroviral therapy. 1568 Oct 97

Etravirine is the first next-generation nonnucleoside reverse-transcriptase inhibitor (NNRTI) that is approved for the treatment of HIV infection in patients who have experienced virologic failure while receiving an NNRTI-containing regimen. The drug is taken as two 100-mg tablets twice daily after a meal. Because the drug is metabolized by cytochrome P450 isoenzymes, it cannot be coadministered with a number of other drugs (fosamprenavir, high-dose ritonavir, atazanavir, rifampin, and several antiepileptic medications). Etravirine demonstrates potent in vitro activity against wild-type and NNRTI-resistant strains of HIV. In vitro resistance and treatment failure is associated with the development of multiple NNRTI resistance mutations other than the K103N mutation. Several large clinical studies have documented the benefit of adding etravirine to an optimized background regimen in patients with virologic failure who are infected with multidrug-resistant HIV. The major adverse effects of etravirine therapy are nausea and rash, which are typically self-limiting and do not lead to treatment discontinuation.
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PMID:Etravirine, a next-generation nonnucleoside reverse-transcriptase inhibitor. 1927 97

Cyclins and cyclin-dependent kinases (CDK) form a key part of the regulatory proteins that govern the cell cycle. Aberrancy in their function can lead to uncontrolled growth and proliferation of the cells which forms the basis of many human diseases, especially cancers. Seliciclib (CYC202, R-roscovitine) is a second-generation CDK inhibitor that competes for ATP binding sites on these kinases, reducing tumor growth and inducing cell death. It is a direct inhibitor of cyclin E/CDK2 and also has inhibitory effects on cyclin H/CDK7 and cyclin T/CDK9. Seliciclib leads to growth arrest and apoptosis of cell lines through activation of the p53 gene, inhibition of RNA processing and blockage of the RNA polymerase II-dependent transcription, and reduction of anti-apoptotic proteins. Seliciclib has good oral bioavailability, although its absorption is slowed by food. It is distributed rapidly to the body tissues and metabolized rapidly to a carboxylated derivative that is excreted by the kidneys. The major adverse effects of seliciclib are electrolyte disturbances (hypokalemia, hyponatremia), gastrointestinal side effects (nausea, emesis, anorexia), fatigue, transient hyperglycemia, elevation of liver enzymes and reversible elevation of serum creatinine. At present, it is in Phase II trials for non-small cell lung cancer and nasopharyngeal carcinoma.
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PMID:Seliciclib in malignancies. 1993 6

Nucleoside analogue reverse-transcriptase inhibitors (NRTIs) especially stavudine, used for the treatment of HIV infection have been rarely associated with lactic acidosis syndrome (LAS) and severe neuromuscular weakness mimicking Guillain Barre syndrome. A 36-year-old man presented with a one-week history of nausea, vomiting, epigastric pain, dyspnea associated with progressive muscle weakness and numbness in glove and stocking pattern. He had symptomatic HIV infection, diagnosed 2 years before the admission and was treated with GPOvir (lamivudine, stavudine and nevirapine). Physical examination revealed afebrile dyspnic drowsy man with crepitation in both lungs and hepatomegaly. Neurological examination showed areflexic symmetrical weakness of both extremities and decreased pin-prick sensation in glove and stocking pattern as well as loss of vibration and touch sensation in both hands and feet. He developed cardiopulmonary arrest and was intubated. Investigations revealed severe lactic acidosis (lactic acid = 21.1 mg/dl). Electrophysiological studies revealed severe sensorimotor axonopathy predominantly involved the lower extremities. Stavudine was discontinued. Severe LAS dramatically improved and polyneuropathy gradually recovered with symptomatic as well as supportive interventions. Monitoring of LAS and neuromuscular weakness is advocated in HIV patient who receive stavudine therapy. Immediate discontinuation of the medication after detection of these complications may prevent this fatal complications.
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PMID:Lactic acidosis associated with severe neuromuscular weakness and stavudine therapy. 2159 38

It is estimated that there are over 5,000 species of mushrooms worldwide. Some of them are edible and some are poisonous due to containing significant toxins. In more than 95% of mushroom toxicity cases, poisoning occurs as a result of misidentification of the mushroom by an amateur mushroom hunter. The severity of mushroom poisoning may vary, depending on the geographic location where the mushroom is grown, growth conditions, the amount of toxin delivered, and the genetic characteristics of the mushroom. Amanita phalloides is the most common and fatal cause of mushroom poisoning. This mushroom contains amanitins, which are powerful hepatotoxins that inhibit RNA polymerase II in liver. Mushroom poisoning is a relatively rare cause of acute liver failure. A 63-year-old male patient was admitted to the emergency room with weakness, nausea, vomiting, and diarrhea. He reported ingesting several wild mushrooms about 36 hours earlier. In this article we report a case of lethal Amanita phalloides intoxication from stored mushrooms.
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PMID:Acute liver failure caused by mushroom poisoning: a case report and review of the literature. 2429 10

Abacavir is a nucleoside reverse-transcriptase inhibitor that has been approved for use in combination with other retroviral agents in the treatment of HIV infection. Common adverse reactions include headache, fatigue, nausea, and rash. A fatal hypersensitivity reaction may occur in 5% of patients receiving abacavir; therefore, screening for HLA-B5701 should be performed before starting abacavir. Alopecia areata (AA) is infrequently reported in HIV-infected patients. Certain underlying conditions have been associated with AA, including a decreased CD4:CD8 ratio related to the progression of HIV infection, some opportunistic infections, and syphilis. Several antiretroviral drugs, such as zidovudine, indinavir, indinavir/ritonavir, lopinavir/ritonavir, and atazanavir/ritonavir have been implicated in the development of AA. At present, the occurrence of AA has not been associated with abacavir use. We cannot exclude that the use of abacavir and the development of AA could be coincidental. Nevertheless, patients given abacavir should be monitored for hair loss and the drug discontinued promptly if such signs appear.
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PMID:Alopecia areata associated with abacavir therapy. 2502 72


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