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)

The inhibitory potency of 3'-azido-3'-deoxythymidine 5'-triphosphate (AZTTP) against HIV-1 reverse transcriptase (HIV-1 RT) has been further evaluated. The results indicate that the previously reported low Ki values for AZTTP against HIV-1 RT (2.35 nM) are due neither to the to the direct tight binding of AZTTP to HIV-1 RT nor to the interaction of the enzyme with AZTMP moiety terminated primer-templates, but instead they are an artifact of the use of a homotemplate-primer [poly(rA).oligo(dT)]. With a set of RNAs of defined sequence as templates, we demonstrate that the observed Ki value for AZTTP depends on the length of the poly(rA) region following the primer in the RNA template. The more adenosyl residues in the RNA template that are available for processive incorporation of TMP moieties, the lower is the observed Ki value for AZTTP. Since the potencies of new inhibitors of HIV-1 RT are usually compared with that for AZTTP, these results have important consequences for the process of discovery of new HIV inhibitors that are of potential use in AIDS therapy.
 ...
PMID:The observed inhibitory potency of 3'-azido-3'-deoxythymidine 5'-triphosphate for HIV-1 reverse transcriptase depends on the length of the poly(rA) region of the template. 137 Oct 70

Chancroid is linked to the spread of human immunodeficiency virus type 1 (HIV-1) in East Africa. Effective, easily administered therapy is a priority for the control of Haemophilus ducreyi. The efficacy of a single oral dose of fleroxacin, 400 mg, was compared to a 3-day oral course of trimethoprim-sulfamethoxazole (TMP-SMZ), 160/800 mg, twice daily for the treatment of chancroid in 98 HIV-1-seronegative men in Nairobi, Kenya. No differences were noted between the two groups with respect to demographic characteristics, sexual behavior, and clinical characteristics. Culture-proven failure occurred in 1 (3%) of 36 fleroxacin-treated patients and in 11 (30%) of 37 TMP-SMZ-treated patients (P = .005). Fleroxacin, as a single oral dose, is an effective treatment for culture-proven chancroid in patients who are HIV-1 seronegative. TMP-SMZ is no longer predictably effective due to the recent emergence of resistance to both sulfonamides and to trimethoprim.
 ...
PMID:A randomized, double-blind study of the efficacy of fleroxacin versus trimethoprim-sulfamethoxazole in men with culture-proven chancroid. 156 47

Drug allergy is the most common and significant allergic manifestation of HIV3 infection. Initially described in patients treated with SMX-TMP for PCP, allergy is now known to involve a multitude of drugs. The pathogenesis of, and risk factors for, allergy in HIV infection are poorly understood, although there is evidence suggesting that allergy is more common with advancing immunodeficiency. HIV-negative subjects with sulfonamide allergy may have drug-specific antibodies and drug metabolite-induced lymphocyte cytotoxicity, abnormalities that could partly explain the allergic mechanisms and which may have future diagnostic potential; these abnormalities have not been described in HIV-infected subjects. Therapy includes avoidance, suppressive agents such as corticosteroids, and desensitization, although the appropriate role for each is not entirely clear. Serum IgE levels have been shown to rise with progressive disease; those patients with higher levels may have a worse prognosis. The mechanisms of this rise are multifactorial, probably a combination of altered T-lymphocyte regulation of IgE synthesis and of production of specific IgE directed against microbial antigens.
 ...
PMID:Allergic manifestations of human immunodeficiency virus (HIV) infection. 167 34

Succinylfluorescein-labeled dideoxyTTP has been used as a substrate for reverse transcriptase from HIV-1. On addition to the 3'-end of a primer molecule, there is a reduction of fluorescence yield of a factor of ca. 4. Release of a fluorescent DNA/DNA primer/template duplex from its complex with reverse transcriptase results in a reduction of fluorescence by a further factor of 2. The fluorescent nucleotide is incorporated somewhat less efficiently than 3'-azidoTMP and TMP, which show similar incorporation kinetics. Fluorescent chain-terminated primers have been used to investigate the interaction of normal and chain-terminated primer/template complexes with reverse transcriptase. The dissociation constant of a 36/18-mer was 0.65 nM, whereas that of the same complex after the addition of the fluorescent chain-terminating nucleotide to the primer was 3 nM at 25 degrees C. The rate of dissociation of the latter complex from the enzyme was 0.04 s-1. This was decreased by a factor of ca. 10 at high concentrations (greater than 200 microM) of the nucleotide triphosphate complementary to the next position of the template. The results obtained suggest that potent inhibition of reverse transcriptase activity in in vitro assays results from formation of a slowly dissociating complex between the enzyme and chain-terminated primer/template complexes. However, arguments are presented that lead to the conclusion that this is not the mode of inhibition in cells invaded by HIV. At the prevailing relative concentrations in this situation, chain termination resulting in incomplete transcription is likely to be the major factor.
 ...
PMID:Interaction of fluorescently labeled dideoxynucleotides with HIV-1 reverse transcriptase. 170 67

Pneumocystis carinii pneumonia complicated the course of two patients with multiple myeloma. The diagnosis was established in both cases by bronchoalveolar lavage, which demonstrated the typical pneumocysts. Clinical and roentgenographic improvement in both patients was observed following a course of trimethoprim-sulfamethoxazole. One patient had lymphocyte subsets performed with a CD4/CD8 ratio of 0.8; both patients were HIV antibody-negative by ELISA. Both patients tolerated prophylactic TMP-SMX given concurrently with the subsequent chemotherapy for myeloma. We suggest that the immune defect seen in multiple myeloma may have placed these patients at risk for opportunistic infections such as P carinii pneumonia; however, as opposed to patients with AIDS, our patients tolerated therapy with TMP-SMZ quite well.
 ...
PMID:Pneumocystis carinii pneumonia complicating multiple myeloma. 199 21

Evidence from the literature strongly supports that high doses of TMP, as used in the treatment of PCP in AIDS patients, have the propensity to cause hyperkalemia by inhibiting sodium channels in the distal nephron, thereby impairing potassium secretion. The mechanism of TMP-induced hyperkalemia is believed to be similar to that of triamterene and amiloride because of the structural similarity of these agents. It is also possible that declining renal function, which is a natural progression of HIV disease, may contribute to the hyperkalemia seen in this patient population. In addition, patients with AIDS also may exhibit a defect in adrenal function, potentiating the hyperkalemic effect of TMP therapy. Therefore, it is crucial for clinicians to monitor closely the serum potassium concentration in this patient population, especially during therapy with high doses of TMP.
 ...
PMID:Hyperkalemia and high-dose trimethoprim/sulfamethoxazole. 763 23

The efficacy and toxicity of trimethoprim-sulfamethoxazole (TMP-SMZ) as primary prophylaxis against Pneumocystis carinii pneumonia (PCP) for patients with human immunodeficiency virus (HIV) infection was assessed by comparing the effects of two dosages (480 or 960 mg once a day) of the drug. The multicenter trial involved 260 HIV-infected patients with CD4 cell counts < 0.2 x 10(9)/L and no history of PCP. Patients were randomly assigned to the treatment groups. After a median follow-up of 376 days (range, 1-1219), none of the patients developed PCP. Most adverse reactions that required discontinuation were seen within the first month of TMP-SMZ use and were seen more frequently and earlier in the 960-mg group (hazard ratio, 1.4; 95% confidence interval, 0.95-2.02; P = .007). For patients with HIV infection, 480 mg of TMP-SMZ is as efficacious as but less toxic than 960 mg of the drug for primary prophylaxis against PCP.
 ...
PMID:Efficacy and toxicity of two doses of trimethoprim-sulfamethoxazole as primary prophylaxis against Pneumocystis carinii pneumonia in patients with human immunodeficiency virus. Dutch AIDS Treatment Group. 776 6

A comparative open study was performed to evaluate the efficacy of single doses of ciprofloxacin (500 mg) and trimethoprim-sulfamethoxazole (TMP-SMZ; 640 mg/3,200 mg) for the treatment of culture-proven chancroid. Clinical cure or improvement was observed 7 days after treatment in 32 (76.2%) of the 42 patients who received ciprofloxacin and 21 (52.5%) of the 40 patients who received TMP-SMZ (P = .04). Cultures for one (4.5%) of 22 patients not cured with ciprofloxacin and 16 (59.3%) of 27 patients not cured with TMP-SMZ were still positive for Haemophilus ducreyi 7 days after treatment (P < .001). Although 77 (71.3%) of the 108 patients tested were seropositive for HIV-1 antibody, HIV infection and the degree of CD4+ lymphocyte depletion had no effect on clinical and bacteriologic outcome. All isolates of H. ducreyi were highly susceptible to ciprofloxacin (MIC, 0.004-0.06 mg/L). In contrast, resistance to TMP-SMZ (MIC, > or = 4/76 micrograms/mL) was observed in 48.9% of isolates (22 of 45) and was significantly associated with treatment failure. Therefore, the administration of TMP-SMZ, in single or multiple doses, is no longer indicated for the treatment of chancroid in Rwanda.
 ...
PMID:Failure of treatment for chancroid in Rwanda is not related to human immunodeficiency virus infection: in vitro resistance of Haemophilus ducreyi to trimethoprim-sulfamethoxazole. 779 96

We report the successful treatment of disseminated Mycobacterium intracellulare osteomyelitis, without evidence of other visceral involvement, in a previously healthy, HIV-negative, 2-year-old female using a 23-month regimen of antimicrobial agents that included 18 months of oral therapy with azithromycin, rifabutin, trimethoprim-sulfamethoxazole (TMP/SMX), and ethambutol.
 ...
PMID:Multifocal M. intracellulare osteomyelitis in an immunocompetent child. 781 41

Cutaneous reactions to penicillin-type antibiotics are usually caused by IgE-mediated reactions directed toward the beta-lactam ring (in penicillin, ampicillin-amoxicillin, and cephalosporins). These allergic reactions may be reliably diagnosed (96% to 99% of the time) with a battery of skin tests derived from penicillin. A few individuals have been identified in Spain, and now Canada, who react to side chains of the beta-lactam antibiotics (and not the beta-lactam ring). Nonallergic cutaneous or systemic reactions to trimethoprim sulfamethoxazole (TMP-SMX) are now an emerging problem among HIV-infected patients. Life-threatening reactions have been described in HIV-infected infants who were rechallenged with TMP-SMX. New 10-day and 48-hour desensitization procedures have been used successfully in some TMP-SMX-reactive patients. Stevens-Johnson syndrome and Lyell's syndrome (toxic epidermal necrolysis) are the most serious of the antibiotic-associated cutaneous reactions. These reactions may be caused by an immune reaction similar to graft-versus-host syndrome. Corticosteroids have been shown to be helpful in the management of Stevens-Johnson syndrome. Although the mortality of toxic epidermal necrolysis is usually high, several children with this disorder have been successfully treated in a burn unit.
 ...
PMID:Antibiotic drug allergy in children. 784 10


1 2 3 4 5 6 7 8 9 10 Next >>