Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026916 (MAC)
 5,226 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies from Africa have been unable to identify disseminated Mycobacterium avium complex (MAC) infection in patients with advanced human immunodeficiency virus (HIV) infection. We performed mycobacterial blood cultures and CD4 counts on 48 symptomatic adults with advanced HIV infection admitted to the hospital in Nairobi, Kenya over 4 weeks in 1992. Fourteen patients had mycobacteremia; these patients had significantly lower CD4 counts than the patients with negative cultures (14/mm3 vs. 85/mm3; p < 0.01). Three patients (6%) were bacteremic with M. avium (mean CD4 count, 10/mm3) and 11 (23%) were bacteremic with Mycobacterium tuberculosis complex (MTB) (mean CD4 count, 15/mm3). Thus, M. avium bacteremia was detected significantly less frequently in the study population than MTB bacteremia (p = 0.04). The minimum rate for HIV-associated disseminated M. avium infection in patients admitted to the hospital in Nairobi was estimated to be approximately 1%. Patients with mycobacteremia died or were discharged home sick before the diagnosis was made. Disseminated M. avium does occur in adults with advanced HIV infection in sub-Saharan Africa, but is less common than disseminated MTB.
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PMID:Disseminated Mycobacterium avium infection among HIV-infected patients in Kenya. 783 2

A wide variety of pathologies afflicting the CNS is see in patients infected with the human immunodeficiency virus. We report the case of relapsing meningoencephalitis caused by Mycobacterium avium intracellulare (MAI) in a homosexual male with the acquired immunodeficiency syndrome in whom repeated use of polymerase chain reaction was required to detect MAI-specific DNA in the cerebrospinal fluid. Successful responses to early empirical antibiotic combination treatment, including the drugs clarithromycin and rifabutin, were demonstrated by clinical, EEG, and CSF improvement during an 8-month period. To our knowledge, this study presents the first known patient with the acquired immunodeficiency syndrome effectively treated for MAI meningoencephalitis and suggests that modern antimycobacterial combination therapy may improve the poor prognosis of CNS infections with nontuberculous mycobacteria.
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PMID:Successful treatment of meningoencephalitis caused by Mycobacterium avium intracellulare in AIDS. 789 10

From July 1, 1991 to March 31, 1992, 156 patients (pts) with positive antibody titers to the human immunodeficiency virus (HIV) were seen in our clinic. A retrospective review of the epidemiology and infectious complications of these patients is presented. There were 129 males and 27 females (4.8:1, ratio). Only 10/156 (12.8%) were non-whites (13 blacks and 7 hispanics). The majority, 126 (80.7%), were 25 to 44 years old. The most common risk factor was homosexuality or bisexuality 100 (64.1%), followed by heterosexual acquisition 25 (16%), intravenous drug abuse 23 (13.7%), unknown 6 (3.8%) and transfusion-related 3 (1.9%). Sixty-five pts had no infections. In the remaining 91 pts, the infections noted were: candidiasis (54 pts); Pneumocystis carinii pneumonia (25 pts); Herpes simplex (13 pts); cytomegalovirus (CMV) retinitis (11 pts) and CMV esophagitis (1 pt), central nervous system toxoplasmosis (8); Herpes zoster (6 pts); cryptococcal meningitis (5 pts); Mycobacterium avium complex bacteremia (4 pts); Molluscum contagiosum, hepatitis-B, staphylococcal infection, perirectal abscess and oral hairy leukoplakia (2 pts each); syphilis, cryptosporidiosis, nocardiosis, histoplasmosis and laryngeal papillomatosis (1 pt each). Infections were multiple in 57/91 (62%) pts and tend to occur more often when the helper cells are < 200 47/57 (82%) pts. Appropriate antimicrobials for prophylaxis and maintenance therapy appeared to decrease the occurrence or relapse of infections such as pneumocystosis, candidiasis, cryptococcosis, tuberculosis and toxoplasmosis.
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PMID:Epidemiology and infectious complications of human immunodeficiency virus antibody positive patients. 790 72

Mycobacterium avium complex (MAC) is frequently isolated from the respiratory or gastrointestinal tract of patients with advanced human immunodeficiency virus (HIV) infection. Whether they are at increased risk of MAC bacteremia and whether culture of respiratory tract or stool specimens is useful for predicting bacteremia are unclear. HIV-infected patients with < or = 50 CD4+ cells/microL were prospectively studied. The risk of MAC bacteremia was approximately 60% within 1 year for patients with MAC in either the respiratory or gastrointestinal tract and was greater than for those without MAC in these sites (relative hazards for respiratory and gastrointestinal tract, 2.3 and 6.0; 95% confidence intervals, 1.1-4.6 and 2.5-14.6, respectively). Both respiratory tract specimen and stool culture had poor sensitivities (22% and 20%, respectively) but good positive predictive values (approximately 60%) for bacteremia. Symptomatic HIV-infected patients with MAC in the respiratory or gastrointestinal tract are at a substantial risk for developing MAC bacteremia; culture of these sites has limited usefulness as a screening test.
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PMID:Mycobacterium avium complex in the respiratory or gastrointestinal tract and the risk of M. avium complex bacteremia in patients with human immunodeficiency virus infection. 790 90

A case-control study was done to determine risk factors for Mycobacterium avium complex (MAC) disease in persons infected with human immunodeficiency virus (HIV) with < 50 CD4+ cells/mm3. In univariate analysis, cases (n = 83) had lower CD4+ cell counts than controls (n = 177) (median, 10 vs. 17/mm3; P < .001) and were more likely to have consumed hard cheese (odds ratio [OR], 5.44; 95% confidence interval [CI], 1.61-18.4) but were less likely to have taken daily showers (OR, 0.55; 95% CI, 0.33-0.94). In multivariate analysis, CD4+ cell count < 25/mm3 (OR, 3.58; 95% CI, 1.71-7.49) and consumption of hard cheese (OR, 5.63; 95% CI, 1.58-20.1) remained associated with disease, while daily showering (OR, 0.58; 95% CI, 0.28-0.88) remained protective. Increased risk for MAC disease in persons with HIV infection and low CD4+ cell counts is not associated with exposure to water or a variety of other environmental sources but may be associated with consumption of hard cheese.
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PMID:Environmental risk factors for acquisition of Mycobacterium avium complex in persons with human immunodeficiency virus infection. 791 81

For identification of the features of disseminated Mycobacterium avium complex (DMAC) in human immunodeficiency virus (HIV)-infected children, a retrospective medical record review of 31 long-term survivors with transfusion-acquired HIV was conducted. Nine patients developed DMAC defined as positive isolation of M. avium complex from peripheral blood. DMAC was diagnosed in patients 51 to 132 months of age (mean, 101). The time from HIV-infecting transfusion to DMAC diagnosis ranged from 37 to 132 months (mean, 92) and survival from the time of DMAC diagnosis ranged from 4 to 21 months (mean, 10). Selected laboratory and clinical measures in DMAC-positive and DMAC-negative subjects were compared. DMAC-positive patients had significantly lower CD4+ T cell counts and higher HIV p24 antigen concentrations than DMAC-negative patients at comparable times. Increased percentages of circulating leukocyte band forms and increased aspartate aminotransferase values were seen more often in DMAC-positive patients. Fever and abdominal pain were the only clinical features seen more often in DMAC-positive than in DMAC-negative patients. At the end of the study period overall survival of DMAC-positive patients was less than that of DMAC-negative children, at 33% vs. 73%. DMAC occurs in profoundly immunocompromised children with advanced HIV disease and significantly affects survival. The clinical and laboratory features of DMAC are relatively nonspecific and a high index of suspicion in patients with markedly reduced CD4+ T cells is essential.
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PMID:A comparative study of transfusion-acquired human immunodeficiency virus-infected children with and without disseminated Mycobacterium avium complex. 791 34

Incidence rates of AIDS illnesses are described among patients with < or = 100 CD4 cells/mm3 grouped by use of antiretrovirals and chemoprophylaxis. Data were obtained from 2646 homosexual men infected with human immunodeficiency virus type 1. Participants were in the Multicenter AIDS Cohort Study during 1985-1993. The incidence rates per 100 person-years for Pneumocystis carinii pneumonia were 47.4 without treatment, 21.5 with antiretrovirals alone, and 12.8 with antiretrovirals combined with chemoprophylaxis. For Kaposi's sarcoma these rates were 23.2, 11.3, and 15.1, respectively. The incidence of some opportunistic infections, including Mycobacterium avium complex, nonretinitis cytomegalovirus disease, and cytomegalovirus retinitis, increased among persons receiving P. carinii pneumonia prophylaxis, because of reduction of this pneumonia and extension of life span. The incidence pattern of AIDS-defining illnesses in patients receiving treatment points to the changing AIDS epidemic and the need for new therapies. The data are particularly relevant to the development and planning of clinical trials and to health care providers.
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PMID:Incidence of clinical AIDS conditions in a cohort of homosexual men with CD4+ cell counts < 100/mm3. Multicenter AIDS Cohort Study. 796 28

The individual antibacterial activities of clofazimine, ethambutol, and rifampin in the treatment of Mycobacterium avium complex bacteremia in patients with AIDS were determined. Sixty human immunodeficiency virus 1-infected patients who had at least one blood culture positive for M. avium complex were randomized to receive either clofazimine (200 mg), ethambutol (15 mg/kg), or rifampin (600 mg) once daily for 4 weeks. Only ethambutol resulted in a statistically significant reduction in the level of mycobacteremia. The median change in individual baseline colony counts was -0.60 log10 cfu/mL after 4 weeks of ethambutol (P = .046). In contrast, median changes in individual baseline colony counts were -0.2 log10 cfu/mL and +0.2 log10 cfu/mL for clofazimine and rifampin, respectively (both, P > .4). Ethambutol had greater antibacterial activity, as determined by changes in the level of mycobacteremia, than either rifampin or clofazimine, supporting its continued use in combination with other agents in the treatment of M. avium infection.
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PMID:The individual microbiologic effect of three antimycobacterial agents, clofazimine, ethambutol, and rifampin, on Mycobacterium avium complex bacteremia in patients with AIDS. 801 92

Otherwise infrequent, infections by non-tuberculous or atypical mycobacteria are now rising in AIDS. Infection with the Mycobacterium avium complex (MAC) is now the most frequent opportunistic bacterial infection, because of better detection of HIV positive patients. The incidence, which is probably underestimated, is now 14-33% in France. The Mycobacterium avium complex is responsible for 96% of infections by atypical mycobacteria in AIDS patients. Diagnosis of infection by MAC is bacteriological. The clinical picture is non-specific and associates high fever, profuse sweating, weight loss and asthenia, all of which make a severe alteration to the general condition. This infection persists in AIDS patients to a late phase of evolution where Immunodeficiency is profound, that is when the level of CD4 lymphocytes is low. Because of this, it is an increasing and preoccupying problem in patients, since it involves the prognosis of life. This shows the importance of prophylactic treatment for this pathology.
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PMID:[A new prophylactic agent in AIDS: Ansatipine. Disseminated Mycobacterium avium complex infection is now the most frequent of the opportunistic bacterial infections in AIDS]. 803 59

Some isolates of simian immunodeficiency virus (SIV) have been shown to infect Sup-T1 cells with slow kinetics and in the absence of cytopathic effects, including cell fusion or CD4 down-modulation (J. A. Hoxie, B. S. Haggarty, S. Bonser, J. Rackowski, H. Shan, and P. Kanki, J. Virol. 62:2557-2568, 1988). In the present study, we describe the isolation and characterization of a SIVmac variant, derived from the BK28 infectious molecular clone, that became highly cytopathic for Sup-T1 cells. This variant, termed CP-MAC, exhibited a number of differences from BK28, including (i) an altered tropism which largely restricted its host range to Sup-T1 cells, (ii) the ability to induce cell fusion and CD4 down-modulation, and (iii) a highly stable interaction of its external (SU) and transmembrane (TM) envelope glycoproteins. In addition, a marked increase in the level of surface envelope glycoproteins was observed both on CP-MAC-infected cells and on virions. The CP-MAC env gene was PCR amplified from infected cells, and sequence analysis identified five amino acid changes in SU and six in TM compared with BK28. The introduction of these changes into BK28 was shown to fully reconstitute the biological and morphological properties of CP-MAC. The limited number of mutations in CP-MAC should enable the molecular determinants to be more precisely defined and help to identify the underlying mechanisms responsible for the striking biological and structural alterations exhibited by this virus.
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PMID:Biological, molecular, and structural analysis of a cytopathic variant from a molecularly cloned simian immunodeficiency virus. 793 60


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