Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Radiolabeled tracers can provide valuable information about the structure of and flux distributions in biocatalytic reaction networks. This method derives from prior studies of glucose metabolism in mammalian systems and is implemented by pulsing a culture with a radiolabeled metabolite that can be transported into the cells and subsequently measuring the radioactivity of all network metabolites following separation by liquid chromatography. Intracellular fluxes can be directly determined from the transient radioactivity count data by tracking the depletion of the radiolabeled metabolite and/or the accompanying accumulation of any products formed. This technique differs from previous methods in that it is applied within a systems approach to the problem of flux determination. It has been used for the investigation of the indene bioconversion network expressed in Rhodococcus sp. KY1. Flux estimates obtained by radioactive tracers were confirmed by macroscopic metabolite balancing and showed that indene oxidation in steady state chemostat cultures proceeds primarily through a monooxygenase activity forming (1S,2R)-indan oxide, with no dehydrogenation of trans-(1R,2R)-indandiol. These results confirmed the significance of indan oxide formation and identified the hydrolysis of indan oxide as a key step in maximizing the production of (2R)-indandiol, a chiral precursor of the HIV protease inhibitor, Crixivan.
 ...
PMID:Application of radiolabeled tracers to biocatalytic flux analysis. 1155 64

In the last five years, as HAART has become standard therapy in HIV seropositive or AIDS patients, changes have been noted in the numbers and types of opportunistic fungal infections in these cohorts of patients. Particularly, oropharyngeal candidiasis have become rare in HIV infected patients since the introduction of new anti-HIV drugs of the protease inhibitors type. At the Immunology Institute of the Universidad Central de Venezuela the most frequent protease inhibitors (PIs) used for the treatment of these patients have been: Nelfinavir (Viracept, Roche), Indinavir (Crixivan Merck), Ritonavir (Norvir, Abbott), Saquinavir (Fortovase, Roche). Recently, we observed that recurrent candidiasis was less frequent and no Candida could be isolated in our patients. A direct relation to the PIs was suspected. In order to assess the "in vitro" antifungal activity of the afore mentioned protease inhibitors on Candida sp., we used both the well diffusion test and the NCCLS broth microdilution test to assay 100 Candida sp. isolates from HIV seropositive or AIDS patients with syntomatic oropharyngeal Candida infection. In general, the data obtained with the well diffusion test were in agreement with those obtained by the broth microdilution test. All 100 isolates were susceptible to Saquinavir and 32 were susceptible to Indinavir using the NCCLS microdilution test, while 97 were susceptible to Saquinavir and 52 to Indinavir by the well diffusion test. From 17 C. albicans resistant to fluconazole, all were susceptible to Saquinavir by the NCCLS micromethod and 16 by the well diffusion test. Our results showed anticandidal activity "in vitro" of PIs, mainly Saquinavir.
 ...
PMID:"In vitro" antifungal activity of protease inhibitors. 1181 41

We have applied the methodology of metabolic engineering in the investigation of the enzymatic bioreaction network in Rhodococcus sp. that catalyzes the bioconversion of indene to (2R)-indandiol suitable for the synthesis of cis-1-amino-2-indanol, a precursor of the HIV protease inhibitor, Crixivan. A chemostat with a novel indene air delivery system was developed to facilitate the study of steady state physiology of Rhodococcus sp. 124. Prolonged cultivation of this organism in a continuous flow system led to the evolution of a mutant strain, designated KY1, with improved bioconversion properties, in particular a twofold increase in yield of (2R)-indandiol relative to 124. Induction studies with both strains indicated that KY1 lacked a toluene-inducible dioxygenase activity present in 124 and responsible for the formation of undesired byproducts. Flux analysis of indene bioconversion in KY1 performed using steady state metabolite balancing and labeling with [14C]-tracers revealed that at least 94% of the indene is oxidized by a monooxygenase to indan oxide that is subsequently hydrolyzed to trans-(1R,2R)-indandiol and cis-(1S,2R)-indandiol. This analysis identified several targets in KY1 for increasing (2R)-indandiol product yield. Most promising among them is the selective hydrolysis of indan oxide to trans-(1R,2R)-indandiol through expression of an epoxide hydrolase or modification of culture conditions.
 ...
PMID:Metabolic engineering of indene bioconversion in Rhodococcus sp. 1181 13

Cis (1S,2R) indanediol is a potential precursor to (-)-cis (1S,2R)-1-aminoindan-2-ol, a key chiral synthon for a leading HIV protease inhibitor, Crixivan (Indinavir). A potential route to the biosynthesis of this important precursor, the microbial asymmetric direduction of 1,2-indanedione to its corresponding diol, cis (1S,2R) indanediol, was investigated. The screening of 32 yeast strains yielded Trichosporon cutaneum MY 1506 as a suitable biocatalyst. At the 2-l shake-flask scale, 1,2-indanedione (charged at 1.0 g/l) was bioconverted to cis (1S,2R) indanediol at a final bioconversion yield of 99.1% and an enantiomeric excess of >99%. When scaled up in a 23-l bioreactor, T. cutaneum produced 8.4 g of pure cis (1S,2R) indanediol, and the isolated yield of cis (1S,2R) indanediol was 52%. Purification of the scale-up also yielded 0.9 g of the more polar trans (1S,2R) indanediol diastereomer, a minor bioreduction product. Supercritical fluid chromatography analyses of the purified cis (1S,2R) and trans (1S,2S) indanediol demonstrated that the enantiomeric excesses during this bioconversion scale-up were 99% and 26%, respectively.
 ...
PMID:Asymmetric direduction of 1,2-indanedione to cis (1S,2R) indanediol by Trichosporon cutaneum MY 1506. 1623 51

Efavirenz is the lead compound of a series of benzoxazinones originally developed by DuPont Merck. It is a non-nucleoside reverse transcriptase inhibitor (NNRTI) under development for the potential treatment of viral infections, including HIV. In June 1998, the company submitted an NDA to the US FDA for the use of efavirenz (as Sustiva) for the treatment of HIV infection [289361]. In July 1998, DuPont purchased Merck's interest in DuPont Merck and the company's name changed to DuPont Pharmaceuticals. The two companies decided to continue to share marketing rights to Sustiva (to be marketed by Merck as Stocrin outside the US, Canada, and certain European countries) [291738]. As of October 1997, triple combination studies of efavirenz were ongoing, or planned, with nelfinavir, indinavir or ritonavir, or other retroviral inhibitors, for the treatment of opportunistic and pediatric viral infections [265945]. Efavirenz is also being evaluated as monotherapy and in combination with zidovudine (Retrovir, AZT) and lamivudine (Epivir, 3TC) (qv). Results of a study in eight HIV-infected patients, reported at the 12th World AIDS Conference in July 1998, showed that efavirenz administration, in dual and triple combinations, achieved HIV-RNA levels in plasma and cerebrospinal fluid (CSF) below the level of detection (fewer than 400 copies/ml) [290881,293994]. In March 1998, Merck signed a letter of intent with Trimeris to conduct a trial of efavirenz in combination with Trimeris's HIV fusion inhibitor, T-20, (qv). The trial will enroll up to 48 HIV-infected individuals at three sites in the US. All enrolled patients will be those who have begun to fail their existing triple combination therapy. Prior exposure to NNRTIs and protease inhibitors, other than indinavir, will be among the exclusion criteria for the study. The first 10 days of the study were planned as a dose-optimization period to assess the safety, pharmacokinetics and antiviral activity of multiple ascending doses of T-20. After completion of this period, subjects will be eligible to participate in an extension period of at least six months, during which T-20 will be administered in combination with efavirenz and two protease inhibitors [281696]. A 137-patient phase III study showed that efavirenz, in combination with zidovudine and lamivudine, caused significant reduction in viral levels and increased CD4 cell levels. The results were presented at the Sixth European Conference on Clinical Aspects and Treatment of HIV Infection (Hamburg, Germany, October 1997) [265945]. At the Fourth Conference on Retroviruses and Opportunistic Infections, in January 1997, data were presented from a clinical trial of efavirenz in combination with indinavir, which showed that, in 82% of the patients, viral load was reduced to undetectable levels, as measured by the Amplicor assay [231410]. Further retrospective analysis showed that the viral load was a significant predictor of long-term (over 52 weeks) viral suppression [265945]. A double-blind, phase II pilot study of efavirenz showed significant activity in HIV-RNA suppression and CD4 cell recovery when evaluated for two weeks alone, and even better results when used in combination with indinavir (Crixivan, qv); 80% of patients achieved HIV-RNA below level of quantification and CD4 cell count elevation averaging 140 cells/mm3. The study evaluated 16 patients for 12 weeks and is ongoing [219671,227966]. A total of 21 patients received indinavir (800 mg, eight hourly) for two weeks, followed by combination therapy with efavirenz (200 mg, once daily). Another group of nine patients received indinavir alone for 26 weeks, followed by the addition of stavudine (Zerit) and efavirenz. In combination use, indinavir dosing was 1.0 g every eight hours. At 26 weeks, approximately 40% of the patients receiving indinavir alonehad plasma levels below 400 copies/ml of HIV-RNA. After stavudine and efavirenz were added, and following 16 weeks of the triple combination, 83% of the patients had plasma levels below 400 copies/ml [247754].
 ...
PMID:Efavirenz DuPont Pharmaceuticals Co. 1846 25

With reference to challenges in developing varied and exceedingly complex scaffolds expeditiously through atom economy, domino reactions have assumed a significant role in several transformative endeavors towards established pharmaceuticals and new chemical entities across diverse therapeutic classes such as HIV integrase inhibitors, DPP4 [dipeptidyl peptidase IV] inhibitors, GSK- 3 (Glycogen Synthase Kinase 3) inhibitors, neoplastic drugs and microtubule antagonists. The very large chemical space of Domino Reactions can be leveraged for the design strategy of drugs and drug- like candidates with leading examples like Indinavir (Crixivan), Trandolapril (Mavik), Biyouyanagin A, endo pyrrolizidinone diastereomer [GSK] and several others. Domino reactions therefore constitute an integral part of both creative and functional aspects of drug design and discovery, contributing both enhanced efficiency as well as synthetic versatility to pharmaceutical drug design.
 ...
PMID:Domino Reactions in Drug Design and Discovery. 2753 90


<< Previous 1 2 3 4 5