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

The replication of recombinant multidrug-resistant HIV-1 clones modeled on clinically derived resistant HIV-1 strains from patients receiving long-term combination therapy with zidovudine (AZT) plus 2',3'-dideoxycytidine was found to regain sensitivity to AZT and stavudine (D4T) as a consequence of a pharmacologically induced decrease in de novo dTMP synthesis. The host-cell system used was phytohemagglutinin-stimulated peripheral blood mononuclear cells; dTMP and dTTP depletion were induced by single exposures to a low level of the thymidylate synthase inhibitor 5-fluorouracil (5-FU) or its deoxynucleoside, 2'-deoxy-5-fluorouridine. The host-cell response to the latter was biphasic: a very rapid decrease in the rate of de novo dTMP formation and, consequently, in intracellular dTTP pools, followed by slower recovery in both indices over 3 to 24 h. With the additional presence of AZT or D4T, however, replication of the multidrug-resistant HIV-1 strains remained inhibited, indicating dependence of HIV DNA chain termination by AZT-5'-monophosphate or 2',3'-didehydro-2', 3'-dideoxythymidine-5'-monophosphate in these resistant strains on simultaneous inhibition of host-cell de novo synthesis of thymidine nucleotides. No effect on viability of control (uninfected) phytohemagglutinin-stimulated/peripheral blood mononuclear cells was noted on 6-day exposures to 5-FU or 2'-deoxy-5-fluorouridine alone or in combination with AZT or D4T, even at drug levels severalfold higher than those used in the viral inhibition studies. These studies may provide useful information for the potential clinical use of AZT/5-FU or D4T/5-FU combinations for the prevention or reversal of multidrug resistance associated with long-term dideoxynucleoside combination therapy.
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PMID:Suppression of replication of multidrug-resistant HIV type 1 variants by combinations of thymidylate synthase inhibitors with zidovudine or stavudine. 1005 38

Trimethoprim-sulfamethoxazole (TMP-SMX) is widely used for Pneumocystis carinii pneumonia prophylaxis in human immunodeficiency virus (HIV)-infected patients, but little is known about the effects of this practice on the emergence of TMP-SMX-resistant bacteria. A serial cross-sectional study of resistance to TMP-SMX among all clinical isolates of Staphylococcus aureus and 7 genera of Enterobacteriaceae was performed at San Francisco General Hospital. Resistance among all isolates was <5.5% from 1979 to 1986 but then markedly increased, reaching 20.4% in 1995. This was most prominent in HIV-infected patients: resistance increased from 6.3% in 1988 to 53% in 1995. The largest increases in resistance were in Escherichia coli (24% in 1988 to 74% in 1995) and S. aureus (0% to 48%) obtained from HIV-infected patients. A rapid increase in the use of prophylactic TMP-SMX in HIV disease was also observed during this time in San Francisco and is likely responsible for the increase in TMP-SMX resistance.
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PMID:Emergence of trimethoprim-sulfamethoxazole resistance in the AIDS era. 1055 35

Our study was undertaken to evaluate if desensitization treatment is more effective than rechallenge in preventing hypersensitivity reactions in HIV-positive patients with previous allergic reactions to TMP-SMX; the secondary aim was to evaluate the frequency of reactions to TMP alone. This was a randomized, multicentre open study. Patients with previous documented hypersensitivity to TMP-SMX who required primary or secondary PCP prophylaxis were enrolled; subjects who had previously had serious adverse reactions to TMP-SMX were excluded. All eligible patients assumed 200 mg TMP for 14 days and in case of no reactions were randomized for desensitization or rechallenge with TMP-SMX. The patients were then followed up by periodical visits for six months. Seventy-three patients were enrolled; 14 subjects (19%) presented reactions on TMP alone during the pre-enrollment phase. The remaining 59 subjects were randomly assigned to the two treatment groups: 34 carried out desensitization (group 1) and 25 rechallenge (group 2) with TMP-SMX. Seven patients in group 1 (20.5%) and seven in group 2 (28%) showed hypersensitivity reactions during treatment; this difference was not statistically significant. No serious reaction occurred in either group. This study showed the comparable effectiveness of the desensitization procedure and rechallenge in patients with a previous, not serious, allergic reaction to TMP-SMX.
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PMID:The effectiveness of desensitization versus rechallenge treatment in HIV-positive patients with previous hypersensitivity to TMP-SMX: a randomized multicentric study. C.I.S.A.I. Group. 1072 62

Toxoplasmic retinochoroiditis is an important opportunistic retinal infection in human immunodeficiency virus (HIV)-infected patients. It may present as diffuse necrotizing retinochoroiditis instead of a focal lesion and may be the initial manifestation of HIV infection. A 50-year-old heterosexual man presented with blurred vision in his left eye of 3 months' duration. Fundus examination revealed diffuse necrotizing retinochoroiditis, mainly at the posterior pole, with marked vitritis in the left eye. Serologic studies and aqueous fluid antibody titers indicated recent toxoplasmic infection. Positive enzyme immunoassays (EIA) and Western blot tests proved HIV infection. The retinochoroiditis and vitritis improved after an antitoxoplasmic regimen with trimethoprim-sulfamethoxazole (TMP-SMX). Nonetheless, toxoplasmic encephalitis developed 6 months after the onset of ocular toxoplasmosis and responded well to TMP-SMX. This is the first case of toxoplasmic retinochoroiditis as the initial manifestation of AIDS reported in Taiwan. We suggest that Toxoplasma infection should be included in the differential diagnosis of diffuse necrotizing retinochoroiditis and vitritis. We also recommend that adults with newly diagnosed ocular toxoplasmosis be screened for HIV infection.
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PMID:Diffuse toxoplasmic retinochoroiditis as the initial manifestation of acquired immunodeficiency syndrome. 1082 Sep 54

The 5'-triphosphate of 4-thiothymidine (4S-TTP) is an excellent substrate for the Klenow fragment of Escherichia coli DNA polymerase 1 and HIV-1 reverse transcriptase with values of k(cat)/Km within a factor of approximately 3 of those for TTP. A large UV change (deltaepsilon= -9770 M(-1)cm(-1) at 340 nm) associated with incorporation of 4S-TMP into nucleic acid duplexes makes possible a rapid, continuous spectrophotometric assay of the reaction progress.
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PMID:Incorporation of 4-thiothymidine into DNA by the Klenow fragment and HIV-1 reverse transcriptase. 1085 57

Trimethoprim-sulfamethoxazole (TMP/SMX) is recognized as the superior agent for Pneumocystis carinii pneumonia (PCP) prophylaxis but a high incidence of adverse drug reactions, which may be due to toxic drug metabolites, limits its use. AIDS Clinical Trials Group protocol 268 was a randomized, double-blind, controlled two-arm trial designed to determine whether gradual initiation of TMP/SMX suspension reduced the incidence of treatment-limiting adverse drug reactions compared with routine initiation of double-strength (DS; 160 mg/800 mg) tablets. In all, 372 HIV-1-infected study subjects with a CD4+ cell count <250 x 10 cells/mm3 who had not previously received TMP/SMX for PCP prophylaxis were randomized to receive either daily TMP/SMX DS tablets or a gradually increasing dose of TMP/SMX suspension. The suspension dose was increased to reach the equivalent of a DS tablet by study day 13. During the first 2 weeks, study subjects also received a matching placebo tablet/suspension. After week 2, all study subjects received TMP/SMX tablets for the next 10 weeks. There were significantly fewer study subjects who discontinued prophylaxis during the first 12 weeks when TMP/SMX therapy was initiated gradually (17%) than when initiated in DS tablet formulation (33%) (p =.0002). Gradual initiation was also associated with significantly fewer adverse drug reactions. Gradual initiation of TMP/SMX for primary PCP prophylaxis reduces the incidence of its treatment-limiting adverse effects.
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PMID:Reduced toxicity with gradual initiation of trimethoprim-sulfamethoxazole as primary prophylaxis for Pneumocystis carinii pneumonia: AIDS Clinical Trials Group 268. 1101 50

The frequency of Nocardia infection in HIV-infected patients has increased during the past few years from 0.3% in 1985 to 1.8% in 1989. Although it is not of great concern as an AIDS-associated infection, the nonspecific clinical presentation in these patients might be confused with other lung infections such as tuberculosis (TB). The mortality rate can be as high as 60%. The authors diagnosed three homosexual men with nocardiasis among 1060 HIV-infected patients (0.2%) in a tertiary care center in Mexico City from 1981 to 1997. The mean age was 32 years. The CD4 count was less than 260 cells/mm3 in all these individuals. The clinical presentations were subacute sinusitis, chronic localized abdominal abscess, and acute disseminated nocardiasis. The respective associated infections were none; TB and cytomegalovirus (CMV); and candidiasis, TB, CMV, Isospora belli, and disseminated Mycobacterium avium complex (MAC). Trimethoprim/sulfamethoxazole (TMP/SMX) was the treatment in all the cases; at the time of this writing, two patients were living and one had died during the acute episode. A literature search uncovered 130 cases of Nocardia infection in HIV patients since 1982. According to the published data and our results, nocardiasis should be suspected in those HIV-infected patients who (1) do not respond to appropriate antituberculous treatment; (2) are intravenous drug users; and (3) develop a characteristic pericardial infection. Finally, adequate surgical or percutaneous drainage of abscesses are extremely valuable for diagnosis and therapy.
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PMID:Nocardiasis in patients with HIV infection. 1955 69

A 35-year old HIV-infected man who has been on AZT and TMP-SMX for five years with CD4 cell counts fluctuating between 150/mm3 and 200/mm3 for the last three years is presented in this case history. Because of elevated serum amylase, he was advised not to add ddI or ddC and decided to discontinue AZT, taking only TMP-SMX for the last six weeks. He begins not to feel well and complains of weight loss, night sweats and a "funny" feeling in his left ear and swelling of his face. Upon examination his face is asymmetric with a pronounced firm, nontender fullness at the angle of his left mandible and a suggestion for similar swelling on the right. He has large (2 to 3 cm), firm, nontender posterior cervical nodes bilaterally, as well as bilateral 4 cm axillary and inguinal nodes. Routine blood chemistries are normal with the exception of the elevated amylase, and a chest X-ray shows increased interstitial markings. It is possible that the patient is on the way to developing Diffuse Infiltrative Lymphocytosis Syndrome (DILS), characterized by the presence of abnormally high numbers of circulating CD8 T cells that infiltrate salivary glands, lungs, and other organs. An elevated serum amylase accompanied by a normal serum lipase also suggests hyperamylasemia of salivary gland origin. Follow-up indicated that the patients' lipase was normal and biopsy of parotid glands was negative for malignancy. It was determined that ddI would not be a retroviral of choice in patients with elevated amylase; a combination of AZT and ddC would be a more prudent choice.
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PMID:Hyperamylasemia and facial swelling in an HIV-infected man. 1136 64

A case history is presented of an HIV-infected female patient with a recurrence of Pneumocystis carinii pneumonia (PCP) and contraindications to use of most drugs for PCP, including pentamidine, trimethoprim-sulfamethoxazole (TMP-SMX), clindamycin, primaquine, and dapsone. Treatment alternatives discussed address risk-benefit analyses of using different drugs. The final treatment decision was to use escalating doses of TMP-SMX, since her previous adverse effects (fever and rash) are not an absolute contraindication to readministration of the drug. Results of this TMP-SMX were good with trivial side effects.
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PMID:A difficult case of PCP. 1136 80

A case of a 45-year-old HIV-infected male who developed a severe throat infection with serious complications is reported. Despite a low CD4 count, the patient suffered only one significant illness in ten years since his diagnosed HIV infection. Overly aggressive antibiotic therapy caused fungal and thrush infections, leading to dehydration and extreme weight loss. The patient was treated with rehydration therapy, antifungal agents, and TMP-SMX, after which other complications, including multiple infections and B-cell lymphoma, were diagnosed. He refused chemotherapy after one course of treatment and was sent home with hospice care.
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PMID:Severe sore throat in a patient with AIDS. 1136 58


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