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Query: UMLS:C0021051 (
immunodeficiency
)
71,517
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
We report a fluorescence polarization immunoassay (FPIA) for zidovudine (azidothymidine;
Retrovir
). This assay is accurate and specific over the clinically relevant range of zidovudine concentrations in serum (from 1 to 1,250 ng/ml; from 0.004 to 4.8 microM) and is unaffected by potentially interfering compounds in the sera of patients with renal or hepatic failure. Cross-reactivity with structural analogs of zidovudine (including zidovudine glucuronide) is less than 0.05%, except for cross-reactivities of 0.2, 0.3, and 0.4% with 3-methylthymidine, 3',5'-dideoxythymidine, and A22U (the optical isomer of zidovudine), respectively. The FPIA for zidovudine is more sensitive and more specific than high-performance liquid chromatography (HPLC); it requires 50 to 60 or 200 versus 500 microliters of serum and is faster to perform (45 specimens per h with the FPIA versus 3 specimens per h with HPLC). The zidovudine FPIA compares well with the radioimmunoassay. A correlation coefficient of 0.992 was observed with 31 serum specimens examined by both methods. All three assays (FPIA, radioimmunoassay, and HPLC) are unaffected by the heat treatment used to inactivate human
immunodeficiency
virus. The zidovudine FPIA should be particularly useful for analyzing specimens from large numbers of human
immunodeficiency
virus-infected patients receiving zidovudine in current clinical trials.
...
PMID:Fluorescence polarization immunoassay for zidovudine. 267 72
'Ampligen', a non-toxic, mismatched polymer of double-stranded RNA with antiviral and immunomodulatory activities reduced the concentration of zidovudine (azidothymidine, AZT; '
Retrovir
', Wellcome) required for inhibitory activity against human
immunodeficiency
virus (HIV) in vitro. At the higher doses of AZT tested, the virustatic activity observed seemed to have a synergistic virustatic relation with ampligen. Thus, combined therapy with ampligen and AZT can be expected to be more beneficial than AZT alone to patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex since AZT regimens that seem to be clinically effective are associated with considerable toxicity.
...
PMID:Mismatched double-stranded RNA (ampligen) reduces concentration of zidovudine (azidothymidine) required for in-vitro inhibition of human immunodeficiency virus. 288 93
A patient with AIDS-related thrombocytopenia (ART) was treated with the new anti-retroviral agent azidothymidine (AZT,
Retrovir
, zidovudine) by the intravenous and oral routes for a period of 20 weeks. After a 6 week period of initial treatment, the platelet count rose from 38,000 to 140,000/mm3. AZT was intentionally discontinued for three weeks over which the platelet count declined to 70,000/mm3. After reinstitution of AZT, the platelet count rose once again and remained near normal levels for over one year. We conclude that AZT may have efficacy against the thrombocytopenia observed in some patients infected with human
immunodeficiency
virus (HIV). The pathogenesis of ART and the mechanisms of action of AZT in this condition remain unknown.
...
PMID:Response of AIDS-related thrombocytopenia to intravenous and oral azidothymidine (3'-azido-3'-deoxythymidine). 311 61
High level resistance to 3'-azido-3'-deoxythymidine (AZT, zidovudine or
Retrovir
) is conferred by the presence of four or five mutations (Met-41-->Leu; Asp-67-->Asn; Lys-70-->Arg; Thr-215-->Tyr or Phe; Lys-219-->Gln) in the human
immunodeficiency
virus (HIV) reverse transcriptase. The order of appearance of these five mutations in asymptomatic patients during therapy has been studied. This has enabled us to propose a model for the acquisition of zidovudine resistance mutations during the treatment of high-risk asymptomatic HIV-infected individuals. A consistent acquisition pattern of mutations at codons 41, 70 and 215 was observed in 17 individuals. Complex mixtures of HIV species containing different combinations of single and linked double resistance mutations were present early in zidovudine therapy in isolates from two patients studied in detail. From these mixtures the linked Leu-41/Tyr-215 genotype outgrew all others initially. The development of each new virus population is likely to be mediated primarily by the increase in the level of drug resistance rather than changes in the growth kinetics of the virus. This leads us to conclude that one major driving force in the outgrowth of different mutant viruses is the selective advantage conferred by higher levels of drug resistance.
...
PMID:Zidovudine treatment results in the selection of human immunodeficiency virus type 1 variants whose genotypes confer increasing levels of drug resistance. 750 70
The lack of a safe, economical murine lentivirus model for human
immunodeficiency
virus type 1 (HIV-1) infection of humans has hampered the preclinical evaluation of potential antiviral compounds, vaccines, and biological response modifiers. A small animal model that does not employ HIV-1 is needed to minimize risk of accidental human exposure, enhance efficient use of scarce experimental compounds, and reduce laboratory space necessary to conduct statistically significant in vivo trials. Feline
immunodeficiency
virus (FIV), an immunosuppressive lentivirus of domestic cats, has been used extensively as an animal model for the pathogenesis and therapy of human HIV-1 infection. Cats, however, are not amenable to large-scale efficacy trials because of their relatively large size, high cost, and limited degree of physiologic characterization, particularly with regard to drug metabolism. To adapt the feline immune system to a small laboratory animal host, severe combined immunodeficient mice (SCID mice) were engrafted with feline lymphoid tissues (forming the SCID-fe mouse) and inoculated with FIV. Two quantitative parameters, the incidence of provirus detection in feline tissue grafts and the level of feline IgG in plasma, were used to demonstrate the antiviral efficacy of 3'-azido-3'-deoxythymidine (AZT, azidothymidine,
Retrovir
, zidovudine) in the SCID-fe system. Of 17 SCID-fe mice inoculated with 7 x 10(6) peripheral blood mononuclear cells (PBMC) from an FIV-infected cat, eight had detectable FIV provirus in both the feline thymus and feline lymph node implants, as measured by polymerase chain reaction (PCR)/Southern blot analysis. Treatment of these mice with AZT at a dose of 125 mg kg-1 day-1 in drinking water beginning 1 day prior to FIV inoculation and continuing throughout the study interval prevented the dual detection of provirus in feline lymph node and thymus grafts of all mice tested. In a separate experiment, the level of spontaneous feline IgG production was quantified by ELISA 2 weeks after FIV inoculation with and without AZT treatment. Mean plasma feline IgG level of five SCID-fe mice inoculated with 10(3) TCID50 cell-free FIV was 2.23 mg ml-1. Mean feline IgG level of five mice inoculated with the same quantity of FIV and treated with AZT beginning 1 day prior to virus inoculation and continuing for 2 weeks thereafter was 14.98 mg ml-1. AZT significantly (P < 0.05) enhanced feline humoral immune function at a virus inoculum titer of 10(3) TCID50.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Reduced provirus burden and enhanced humoral immune function in AZT-treated SCID-feline mice inoculated with feline immunodeficiency virus. 761 56
A potential pharmacokinetic interaction between rifampin (Rimactan, Rifadin) and zidovudine (AZT,
Retrovir
) was investigated in the population of human
immunodeficiency
virus-infected patients at our hospital. The results from four patients who were on long-term (> or = 6 months) combination therapy with zidovudine and rifampin are presented. In all cases of combined use of zidovudine and rifampin, a lower area under the plasma concentration-time curve (AUC) and, consequently, a higher apparent clearance of zidovudine were found, compared with a reference population of zidovudine users. Patients had a low to normal maximum concentration of zidovudine in plasma. Elimination half-lives were normal in all but one patient. Zidovudine glucuronide concentrations were determined in three patients and three control subjects. The patients all had relatively higher peak plasma concentrations and higher AUCs of zidovudine glucuronide than the control subjects. In one patient, zidovudine and zidovudine glucuronide were also measured 2.5 months after discontinuation of rifampin. The AUC of zidovudine increased by a factor of 2. These data are in agreement with an enzyme-inducing effect of rifampin on the glucuronidation of zidovudine. They indicate that long-term combination therapy of rifampin and zidovudine leads to increased clearance of zidovudine, which may have therapeutic consequences.
...
PMID:Pharmacokinetic interaction between rifampin and zidovudine. 836 70
No commercial vaccine [correction of vacine] exists for feline
immunodeficiency
virus (FIV), and although feline leukemia virus (FeLV) vaccines are available, they are neither 100% effective nor used in all cats. These realities clearly indicate the veterinarian will be required to treat either FeLV- or FIV-positive cats for some time to come. The management of FIV- or FeLV-positive cats may require supportive therapies as well as virus-specific therapies such as zidovudine (AZT;
Retrovir
, Burroughs Wellcome, Research Triangle Park, NC).
...
PMID:Caring for the retrovirus infected cat. 882 May 95
Recent clinical trials examining 3'-azido-3'-deoxythymidine (AZT, zidovudine, or
Retrovir
) combined with L-2', 3'-dideoxy-3'-thiacytidine (3TC or lamivudine) have shown that combination therapy with these nucleoside analogs affords significant virological and clinical benefits. The addition of 3TC to AZT delays AZT resistance in therapy-naive patients and can restore viral AZT susceptibility in patients who previously received AZT alone. In some AZT-experienced patients, the virological response to AZT-3TC therapy is not sustained and virus resistant to both drugs can be identified. To gain insight into the possible mechanism of dual resistance, we studied a recently described variant resistant to both AZT and 3TC and obtained by simultaneous passage of an AZT-resistant clinical isolate in cell culture with AZT and 3TC. Genetic mapping and site-directed mutagenesis experiments demonstrated that a polymorphism at codon 333 (Gly to Glu) of human
immunodeficiency
virus type 1 reverse transcriptase (RT) was critical in facilitating dual resistance in a complex background of AZT and 3TC resistance mutations. To assess the potential clinical relevance of RT codon 333 changes, we studied dually resistant viruses from patients taking AZT and 3TC. Genetic mapping of RT molecular clones derived from patients' plasma samples demonstrated that in some cases polymorphism at codon 333 was responsible for facilitating dual resistance.
...
PMID:A novel polymorphism at codon 333 of human immunodeficiency virus type 1 reverse transcriptase can facilitate dual resistance to zidovudine and L-2',3'-dideoxy-3'-thiacytidine. 957 80
The thymus is a major target organ in human
immunodeficiency
virus type 1 (HIV-1)-infected children and feline
immunodeficiency
virus (FIV)-infected young cats (G. A. Dean and N. C. Pedersen, J. Virol. 72:9436-9440, 1998; J. L. Heeney, Immunol. Today 16:515-520, 1995; S. M. Schnittman et al., Proc. Natl. Acad. Sci. USA 87:7727-7731, 1990; T. A. Seemayer et al., Hum. Pathol. 15:469-474, 1984; H.-J. Shuurn et al., Am. J. Pathol. 134:1329-1338, 1989; J. C. Woo et al., J. Virol. 71:8632-8641, 1997; J. C. Woo et al., AIDS Res. Hum.
Retrovir
. 15:1377-1388, 1999). It is likely that the accelerated disease process in children and cats is due to infection of the thymus during the time when generation of naive T lymphocytes is needed for development of the mature immune system. Zidovudine (ZDV) monotherapy, which is used to prevent and treat perinatal HIV-1 infection (R. Sperling, Infect. Dis. Obstet. Gynecol. 6:197-203, 1998), previously had been shown to reduce viral burden in FIV-infected young cats (K. A. Hayes et al., J. Acquir. Immune Defic. Syndr. 6:127-134, 1993). The purpose of this study was to evaluate the effect of drug-induced reduction of viral burden in the thymus on virus-mediated thymic involution and peripheral blood CD4 decline using FIV-infected cats as a model for pediatric HIV-1 infection. Eight-week-old cats were randomly assigned to uninfected, saline-treated; uninfected, ZDV-treated; FIV-infected, saline-treated; and FIV-infected, ZDV-treated groups. Parameters measured included blood lymphocyte numbers, viral load in blood and thymic tissue, and thymic histopathology. While the viral burden was significantly reduced by ZDV monotherapy in peripheral blood lymphocytes, plasma, and thymus, thymic lesions were similar for the treated and untreated FIV-infected cats. Further, markedly lowering the viral burden did not increase blood CD4 lymphocyte numbers or prevent their decline. The data suggest that an inflammatory process continued in spite of reduced virus replication. These observations imply that reducing virus load and limiting thymic inflammation are separate factors that must be addressed when considering therapeutic strategies aimed at preserving thymic function.
...
PMID:Antiviral therapy reduces viral burden but does not prevent thymic involution in young cats infected with feline immunodeficiency virus. 1095 86
3'-Azido-3'-deoxythymidine (AZT) is the most widely used and evaluated chemotherapeutic agent for the treatment of persons with acquired immune deficiency syndrome (AIDS) and persons seropositive for human
immunodeficiency
virus (HIV). The National Cancer Institute nominated AZT for toxicity and carcinogenicity studies because of the impending large-scale use of AZT in the treatment of adult patients with AIDS or AIDS-related complex. alpha-Interferon A/D, which displays antiviral activity in mice, is a hybrid molecule composed of the N-terminal portion of human alpha-interferon A and the C-terminal portion of human alpha-interferon D. AZT and alpha-interferon A/D combination studies were conducted because in vitro studies of AZT and alpha-interferon have demonstrated that the combination is more effective in blocking HIV infection than either agent alone. Male and female B6C3F1 mice received AZT (approximately 98% pure) in 0.5% aqueous methylcellulose by gavage for 14 weeks or 2 years. In addition, male and female B6C3F1 mice received alpha-interferon A or alpha-interferon A/D by subcutaneous injection for 2 years, and male and female B6C3F1 mice received AZT in 0.5%% aqueous methylcellulose by gavage in combination with alpha-interferon A/D by subcutaneous injection for 2 years. Genetic toxicology studies were conducted in Salmonella typhimurium, cultured Chinese hamster ovary cells, mouse bone marrow erythrocytes, and mouse peripheral blood erythrocytes. 14-WEEK AZT STUDY: Groups of 10 male and 10 female mice received AZT in 0.5% methylcellulose by gavage at doses of 0, 50, 100, 200, 800, or 2,000 mg/kg daily for 14 weeks. Additional groups of 10 male and 10 female mice received AZT in 0.5% methylcellulose by gavage at doses of 0, 100, 800, or 2,000 mg/kg daily for 14 weeks and then were held without treatment for an additional 4 weeks before necropsy. One female receiving 100 mg/kg and two females receiving 200 mg/kg died during week 1 as a result of gavage trauma; one female receiving 2,000 mg/kg also died prior to the end of the 14-week dosing period. One female receiving 2,000 mg/kg in the recovery study also died from gavage trauma during week 1. The final mean body weights of dosed mice were similar to those of the vehicle control groups at the end of the dosing period and at the end of the recovery period. Female mice receiving 200, 800, or 2,000 mg/kg gained less weight than the vehicle controls during the 14-week dosing period. Exposure to AZT was toxic to the bone marrow, resulting in significant changes in the peripheral blood (decreased hematocrit values, erythrocyte counts, and hemoglobin concentrations, and increased mean cell volume and mean cell hemoglobin) and bone marrow (erythroid hypoplasia) characteristic of a dose- and time-dependent, minimal to moderate, poorly regenerative macrocytic anemia. At the end of the 4-week recovery period, the hematology parameters had returned to normal, indicating that the hematotoxicity was reversible. 2-YEAR STUDIES: AZT Groups of 95 male and 95 female mice received AZT in 0.5% methylcellulose by gavage at daily doses of 0, 30, 60, or 120 mg/kg body weight, administered as two equal doses at least 6 hours apart, 5 days per week for 105 weeks. Each group of 95 animals was composed of a core group of 50 animals for evaluation of carcinogenic response, a group of 30 animals for evaluation of hematology and bone marrow cellularity, and a group of 15 animals from which blood was drawn for determination of plasma AZT concentrations at week 54. alpha-Interferon A/D and AZT/alpha-Interferon A/D Studies Groups of 80 male and 80 female mice received AZT in 0.5% aqueous methylcellulose by gavage at daily doses of 0, 30, 60, or 120 mg/kg body weight, given in two equal doses, 5 days per week for 105 weeks. Those groups receiving AZT also received sub-cutaneous injections of 500 or 5,000 U alpha-interferon A/D three times per week for 105 weeks. Additional groups of 80 male and 80 female mice received subcutaneous injections of the vehicle, 500 U alpha-interferon A/D, 5,000 Uutaneous injections of the vehicle, 500 U α-interferon A/D, 5,000 U α-interferon A/D, or 5,000 U α-interferon A, three times per week for 105 weeks. Each group of 80 animals was composed of a core group of 50 animals for evaluation of carcinogenic response and a group of 30 animals for evaluation of hematology and bone marrow cellularity. Because of the large number of animals involved, the 2-year studies were started in four phases and, for clarity, are presented as follows: the AZT study, the α-interferon A/D study, the AZT/500 U α-interferon A/D study, and the AZT/5,000 U α-interferon A/D study. Design of the 2-year AZT, AZT/α-Interferon A/D, and α-Interferon A/D Studies AZT Dose AZT Study AZT/500 U α-Interferon A/D Study AZT/5,000 U α-Interferon A/D Study 500 or 5,000 U α-Interferon A/D or 5,000 U α-Interferon A Study Vehicle Control 95 male and 95 female micea 80 male and 80 female miceb 80 male and 80 female miceb 80 male and 80 female miceb 30 mg/kg AZT 95 male and 95 female mice 80 male and 80 female mice 80 male and 80 female mice none 60 mg/kg AZT 95 male and 95 female mice 80 male and 80 female mice 80 male and 80 female mice none 120 mg/kg AZT 95 male and 95 female mice 80 male and 80 female mice 80 male and 80 female mice none aFor the AZT study, there were 95 male and 95 female mice; these were divided into 50 males and 50 females in the core groups, 30 males and 30 females in the clinical pathology groups (hematology and bone marrow analyses only), and 15 males and 15 females for plasma AZT concentration determinations. bFor the α-interferon A/D study and the AZT/α-interferon A/D studies, there were 80 male and 80 female mice for each study; these were divided into 50 males and 50 females in the core groups and 30 males and 30 females in the clinical pathology groups (hematology and bone marrow analyses only). Survival and Body Weights Survival and mean body weights of mice exposed to AZT, α-interferon A, α-interferon A/D, or AZT plus α-interferon A/D were generally similar to those of the vehicle control groups. Hematology and Bone Marrow Analyses All groups of male and female mice receiving AZT exhibited changes in peripheral blood and bone marrow characteristic of a dose- and time-dependent, minimal to mild, macrocytic, nonresponsive anemia. In females, these changes were evident throughout the study. In males, the macrocytic anemia had resolved by week 80 in the 30 mg/kg group; at study termination erythrocyte macrocytosis was present only in males receiving 60 or 120 mg/kg AZT or AZT plus α-interferon A/D. There were no treatment-related alterations in hematology or bone marrow parameters in groups that received only α-interferon A or A/D. Pathology Findings Incidences of squamous cell carcinoma and squamous cell papilloma or carcinoma (combined) of the vagina occurred with a positive trend and were significantly increased in groups of female mice receiving 60 or 120 mg/kg AZT alone or in combination with α-interferon A/D. Epithelial hyperplasia was observed in all dosed groups of females, and the incidence was significantly increased in the 120 mg/kg AZT group. Three renal tubule adenomas and one renal tubule carcinoma were observed in male mice receiving 120 mg/kg AZT; the combined incidence in this group exceeded the range in historical controls. A renal tubule adenoma was observed in one male receiving 60 mg AZT/kg and 500 U α-interferon A/D; how ever, none were observed in other groups. Evaluation of step sections revealed a few more renal tubule hyperplasias but no additional neoplasms. The incidence of harderian gland adenoma was increased in male mice receiving 120 mg/kg AZT and exceeded the range in historical controls. Harderian gland neoplasms were observed in other groups but did not follow a treatment-related pattern. Overall Incidences of Vaginal Neoplasms and Hyperplasia of the Vaginal Epithelium in Female Mice in the 2-Year Gavage Studies of AZT and AZT/α-Interferon A/Da Vehicle Control 30 mg AZT/kg 60 mg AZT/kg 120 mg AZT/kg AZT alone 2/197 (1%)b 1/197 0/49 (0%) 3/49 5/45 (11%%) 4/45 11/49 (22%%) 11/49 500 U α-Interferon A/D 0/49 (0%%) 0/49 0/44 (0%) 4/44 5/48 (10%) 8/48 6/48 (13%) 12/48 5,000 U α-Interferon A/D 1/50 (2%) 1/50 1/48 (2%) 4/48 5/48 (10%) 8/48 4/50 (8%) 15/50 aData are presented as number of vaginal neoplasms/number of animals microscopically examined (first line) and number of vaginal hyperplasias/number of animals microscopically examined (second line) bCombined incidences of controls from the AZT alone study and the AZT/α-interferon A/D studies; incidences in the vehicle control group from the AZT alone study are 0/50 (0%%) (neoplasms) and 0/50 (hyperplasia) Overall Incidence of Harderian Gland Neoplasms in Male Mice in the 2-Year Gavage Studies of AZT and AZT/α-Interferon A/Da Vehicle Control 30 mg AZT/kg 60 mg AZT/kg 120 mg AZT/kg AZT alone 13/200 (6%%)b 5/50 (10%%) 2/50 (4%) 10/50 (20%%) 500 U α-Interferon A/D 3/50 (6%) 3/50 (6%) 1/50 (2%%) 4/50 (8%%) 5,000 U α-Interferon A/D 3/50 (6%) 9/50 (18%%) 4/50 (8%%) 4/50 (8%) aData are presented as number of harderian gland neoplasms/number of animals necropsied bCombined incidences of controls from the AZT alone study and the AZT/α-interferon A/D studies; incidence in the vehicle control group from the AZT alone study is 3/50 (6%) Male mice had a pattern of nonneoplastic liver lesions along with silver-staining helical organisms within the liver consistent with an infection with Helicobacter hepaticus. An organism compatible with H. hepaticus was confirmed by polymerase chain reaction-restriction fragment length polymorphism-based assays. Detection of dose-related differences in neoplasm incidences in these studies was not considered to have been significantly impacted by the infection with H. hepaticus or its associated hepatitis. GENETIC TOXICOLOGY: AZT is mutagenic in vitro and in vivo. It induced gene mutations in Salmonella typhimurium strain TA102, with and without S9; no increases in mutations were noted in the other tested strains of S. typhimurium. AZT induced sister chromatid exchanges, but not chromosomal aberrations, in cultured Chinese hamster ovary cells, with and without S9. In vivo studies with male mice administered AZT by gavage showed highly significant increases in micronucleated erythrocytes in bone marrow and peripheral blood after exposure periods that ranged from 72 hours to 14 weeks. CONCLUSIONS: Under the conditions of these 2-year gavage studies there was equivocal evidence of carcinogenic activity of AZT in male mice based on increased incidences of renal tubule and harderian gland neoplasms in groups receiving AZT alone. There was clear evidence of carcinogenic activity of AZT in female mice based on increased incidences of squamous cell neoplasms of the vagina in groups that received AZT alone or in combination with α-interferon A/D. Hematotoxicity occurred in all groups that received AZT. Treatment with AZT alone and AZT in combination with α-interferon A/D resulted in increased incidences of epithelial hyperplasia of the vagina in all dosed groups of females. Synonyms: AZT; 3'-azido-2',3'-dideoxythymidine; azidodeoxythymidine; azidothymidine; 3'-azidothymidine; 3'-deoxy-3'-azidothymidine; 3'-deoxy-(8CI) (9CI); BW A509U;
Compound S
; ZDV; zidovudine Trade name: Retrovir®
...
PMID:NTP Toxicology and Carcinogenesis Studies of AZT (CAS No. 30516-87-1) and AZT/alpha-Interferon A/D B6C3F1 Mice (Gavage Studies). 1257 4
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