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

An infant who received multiple transfusions during the first few days of life for rhesus disease became ill with recurrent infections when 6 months old. Hepatitis, thrush, Candida dermatitis, otitis media, and disseminated Mycobacterium avium intracellulare infection occurred by 14 months of age. Immunological studies showed raised immunoglobulin levels, decreased mononuclear-cell responses to allogeneic cells and mitogen, and a decreased helper/suppressor cell ratio. It was determined that one of the blood donors, who was well at the time of blood donation, had died 17 months after with multiple opportunistic infections and acquired immunodeficiency. The clinical and laboratory findings in our patient suggest that he acquired a transmissible infectious agent from a blood transfusion, resulting in acquired immunodeficiency, and that this agent was not cytomegalovirus, Epstein-Barr virus, or hepatitis B virus.
 ...
PMID:Acquired immunodeficiency in an infant: possible transmission by means of blood products. 613 70

Fourteen previously healthy young patients with unusual community-acquired opportunistic infections were seen over a period of three years. They differ from patients previously described in that 11 were heterosexual drug abusers (including two women) and only three were homosexual men. There were eight Puerto Ricans, five blacks, and one white. Infections included Pneumocystis carinii pneumonia (seven), disseminated Mycobacterium intracellulare infection, histoplasmosis, cryptococcosis, and cytomegalovirus infection (one each), oral thrush (13), and Candida esophagitis (two). All patients had impaired cellular immunity manifested by cutaneous anergy and lymphopenia, and all 11 tested had a markedly decreased ratio of T helper/inducer cells to T suppressor/cytotoxic cells. Twelve had evidence of associated viral infection (Epstein-Barr virus in nine, cytomegalovirus in five, Herpes simplex type 2 in two). Clinical presentation was with a severe opportunistic infection or with a prodrome consisting of oral thrush and nonspecific findings including malaise, fever, lymphadenopathy, or cough. The syndrome of immunodeficiency and opportunistic infection occurs in nonwhite heterosexual drug abusers, not exclusively in white homosexual men, and patients may present for medical care before the onset of a severe opportunistic infection.
 ...
PMID:Community-acquired opportunistic infections and defective cellular immunity in heterosexual drug abusers and homosexual men. 621 79

Disseminated Mycobacterium avium complex (MAC) infection is an important opportunistic infection in AIDS patients. Because cells of macrophage lineage are targets for both human immunodeficiency virus (HIV) and MAC, the monocytoid cell line U937 was coinfected with both pathogens. Coinfected cultures had increased HIV replication (more than threefold at day 6) and an increased percentage of HIV-infected cells compared with cultures infected only with HIV. The kinetics of HIV replication were significantly increased in this coinfection system as measured by flow cytometry. When cells were infected concurrently, the rate of intracellular growth of MAC was not significantly affected. However, cells preinfected with HIV before infection with MAC showed significant enhancement of MAC growth compared with control cells. The kinetics of cell death were also increased in the coinfection system compared with singly infected controls. Thus, coinfection of monocytoid cells with HIV and MAC in vitro results in reciprocal enhancement of multiplication.
 ...
PMID:Human immunodeficiency virus and Mycobacterium avium complex coinfection of monocytoid cells results in reciprocal enhancement of multiplication. 752 54

Mycobacterium avium complex (MAC) in simian immunodeficiency virus (SIV)-infected macaques is a frequent opportunistic infection that shares many features with the condition in human AIDS patients. A retrospective analysis of necropsies on 135 macaques with SIV-induced simian AIDS that received neither antiretroviral nor antimicrobial therapy revealed that 17% (23/135) were infected with MAC. MAC developed in 31.3% (21/67) of the animals inoculated with uncloned SIVmac251 versus 1.9% (1/53) and 6.7% (1/15) of the animals inoculated with the molecular clones SIVmac239 and SIVmac239/316EM, respectively (P = .001). This is the first example in which the risk of infection with a specific opportunistic organism was affected by the infecting strain of immunodeficiency virus. In addition, animals with MAC had a longer mean survival after primary infection and lower CD4 cell counts at death than animals that did not develop this opportunistic infection. The SIV-inoculated macaque is a valuable model in which to study the pathogenesis of MAC in the immunocompromised host.
 ...
PMID:Mycobacterium avium complex in macaques with AIDS is associated with a specific strain of simian immunodeficiency virus and prolonged survival after primary infection. 756 Dec 1

A 28-year-old hemophilia A patient was admitted to our hospital in July, 1991 because of high fever, chronic diarrhea and anemia. The patient had been recognized as a asymptomatic carrier of human immunodeficiency virus (HIV) in 1985 and had developed Pneumocystis carinii pneumonia and had been diagnosed as acquired immunodeficiency syndrome (AIDS) in 1990. Hematologic laboratory examinations on admission revealed pancytopenia and a CD4+ cell count of 3/mm3. X-ray findings of chest and abdomen were normal and bacterial cultures of sputum, urine, blood, stool, cerebrospinal fluid and bone marrow yielded no pathogenic microorganisms. Microscopical examination of the stained specimens showed no acid-fast bacilli. On his fifth hospital day, his liver and spleen enlarged markedly and an abdominal CT scan obtained on the 13th day revealed high-grade hepatosplenomegaly. Administration of several kinds of antibiotics, antifungal agents, antiviral agents, antituberculous agents and gamma-globulin medicines did not relieve the symptoms. On the 28th day the patient had developed a subarachnoid hemorrhage and died five days later. Retrospectively all cultures for acid-fast bacilli of the specimens on his admission yielded nontuberculous mycobacteria. The bacteria were identified as Mycobacterium avium by polymerase chain reaction and his disease was eventually diagnosed as disseminated Mycobacterium avium complex (MAC) infection. The liver and spleen weighed 2,660 g and 1,840 g respectively at autopsy. Although hepatosplenomegaly is commonly recognized in AIDS patients with disseminated MAC infection, such massive and rapid enlargement has been rarely observed. This case study emphasize the importance of diagnosis and rapid treatment at the early stage of MAC infection.
 ...
PMID:[Massive and progressive hepatosplenomegaly caused by disseminated nontuberculous mycobacteriosis in a patient with acquired immunodeficiency syndrome]. 756 51

We conducted a retrospective study to further elucidate the clinical presentations and prognosis of disease due to Mycobacterium kansasii in patients infected with human immunodeficiency virus (HIV). Forty-nine HIV-infected patients first had M. kansasii isolated at a mean CD4 cell count of 62/mm3 and at a mean interval of 17 months after the diagnosis of AIDS. Seventeen of the 49 patients had disseminated disease caused by M. kansasii. Twenty-nine patients had a positive acid-fast smear of sputum, and 35 were known to be cigarette smokers. At the time of initial isolation of M. kansasii, 13 patients had other concurrent pulmonary isolates and 15 had another mycobacterial species concurrently isolated (the Mycobacterium avium complex in 13 instances). Patients who received antimycobacterial treatment survived longer than those who did not. Only one of the 49 patients was definitively determined to be colonized with M. kansasii without disease; therefore, it appears that pulmonary isolates of M. kansasii in HIV-infected patients are almost always associated with disease. The increase in rates of M. kansasii disease among HIV-infected patients has paralleled the rise of AIDS in Louisiana. So far, this state has recorded more coinfections with M. kansasii and HIV than any other.
 ...
PMID:Clinical manifestations and implications of coinfection with Mycobacterium kansasii and human immunodeficiency virus type 1. 878 41

Acute pancreatitis, reported in 17% of pediatric patients with acquired immune deficiency syndrome (AIDS), is said to have a poor prognosis. We describe the pancreatic changes observed at autopsy from 71 children with human immunodeficiency virus (HIV) infection and document their nature, extent, and clinical relevance. The median age at autopsy of the children was 17 months (range, 2 months to 19 years); 38 were boys and 33 were girls. Parental intravenous drug use was the most frequent risk factor for AIDS, followed by blood transfusions. Respiratory failure and sepsis constituted the predominant causes of death. Nonspecific changes, such as edema, inflammation, fibrosis, inspissated material in acini and ducts, and enlarged Langerhans' islet predominated. Acute and chronic pancreatitis were mild except in one instance of a fatal acute probably dideoxyinosine-associated pancreatitis. Pancreatic involvement by opportunistic infections, such as cytomegalovirus (CMV), Mycobacterium avium intracellulare (MAI), and Candida, was focal and rare despite the high prevalence of these infections at autopsy. Focal lymphoplasmacytic infiltration and vascular calcifications were also observed. We conclude that pancreatic changes were frequently noted at autopsy in children with AIDS. They were usually mild, reflected systemic disease states, and were usually not life threatening. The incidence of opportunistic infections of the pancreas was low.
 ...
PMID:Pancreatic disorders in pediatric acquired immune deficiency syndrome. 762 49

We have described a virus termed CP-MAC, derived from the BK28 molecular clone of simian immunodeficiency virus, that was remarkable for its ability to infect Sup-T1 cells with rapid kinetics, cell fusion, and CD4 down-modulation (C. C. LaBranche, M. M. Sauter, B. S. Haggarty, P. J. Vance, J. Romano, T. K. Hart, P. J. Bugelski, and J. A. Hoxie, J. Virol. 68:5509-5522, 1994 [Erratum 68:7665-7667]). Compared with BK28, CP-MAC exhibited a number of changes in its envelope glycoproteins, including a highly stable association between the external (SU) and transmembrane (TM) molecules, a more rapid electrophoretic mobility of TM, and, of particular interest, a marked increase in the level of envelope protein expression on the surface of infected cells. These changes were shown to be associated with 11 coding mutations in the env gene (5 in SU and 6 in TM). In this report, we demonstrate that a single amino acid mutation of a Tyr to a Cys at position 723 (Y723C) in the TM cytoplasmic domain of CP-MAC is the principal determinant for the increased expression of envelope glycoproteins on the cell surface. When introduced into the env gene of BK28, the Y723C mutation produced up to a 25-fold increase in the levels of SU and TM on chronically infected cells, as determined by fluorescence-activated cell sorter analysis with monoclonal and polyclonal antibodies. A similar effect was observed when a Tyr-to-Cys change was introduced at the analogous position (amino acid 721) in the SIVmac239 molecular clone, which, unlike BK28 does not contain a premature stop codon in its TM cytoplasmic tail. Substituting other amino acids, including Ala, Ile, and Ser, at this position produced increases in surface envelope glycoproteins that were similar to that observed for the Cys substitution, while a Tyr-to-Phe mutation produced a smaller increase. These results could not be accounted for by differences in the kinetics or efficiency of envelope glycoprotein processing or by shedding of SU from infected cells. However, immunoelectron microscopy demonstrated that the Y723C mutation in BK28 produced a striking redistribution of cell surface envelope molecules from localized patches to a diffuse pattern that covered the entire plasma membrane. This finding suggests that mutation of a Tyr residue in the simian immunodeficiency virus TM cytoplasmic domain may disrupt a structural element that can modulate envelope glycoprotein expression on the surface of infected cells.
 ...
PMID:A single amino acid change in the cytoplasmic domain of the simian immunodeficiency virus transmembrane molecule increases envelope glycoprotein expression on infected cells. 763 63

Mycobacterium avium intracellulare (MAI) infection is a serious opportunistic infection that occurs in children with human immunodeficiency virus (HIV) infection. In MAI the hematologic system is profoundly affected. In the present study the hematologic manifestations of MAI in 37 HIV-infected infants and children were reviewed. Anemia was the predominant feature in all patients, with severe anemia (hemoglobin < 6 g/dL) occurring in 7 of 34 (21%) patients. This was followed by leukopenia (79%), monocytosis (82%), thrombocytopenia (59%), leukoerythroblastic reaction (68%), and neutropenia (41%). Serum tumor necrosis factor (TNF)-alpha was markedly elevated in all patients with MAI with an X +/- SE of 702 +/- 182 pg/mL. There was an association between elevated TNF-alpha and anemia in these patients.
 ...
PMID:Elevated tumor necrosis factor-alpha in association with severe anemia in human immunodeficiency virus infection and Mycobacterium avium intracellulare infection. 764 Jan 75

Pentoxifylline, a tumor necrosis factor-alpha (TNF) inhibitor, is being tested as a treatment adjunct in human immunodeficiency virus (HIV)-infected patients. However, TNF is important in cellular defense. The effect of pentoxifylline on Mycobacterium avium complex (MAC) growth in exogenously infected macrophages was compared with the effect of dexamethasone. Pentoxifylline, in a concentration that decreased MAC-induced TNF by 48.1%, enhanced MAC growth by 1.9- to 19.6-fold and 1.82- to 4.46-fold in macrophages from normal and HIV-infected patients, respectively. It also induced interleukin-6 (IL-6) in infected macrophages. IL-6 induction correlated with the increase in MAC growth (y = 0.89 + 0.266x, P = .025). Dexamethasone in an equivalent TNF-suppressing concentration also increased MAC growth but was less effective. Unlike pentoxifylline, dexamethasone suppressed IL-6 and the suppression correlated inversely with MAC growth (y = 0.248 + 9.942x, P = .003). Thus, TNF and IL-6 are important in macrophage defense against MAC. Pentoxifylline and dexamethasone should be used with caution in AIDS patients.
 ...
PMID:Pentoxifylline impairs macrophage defense against Mycobacterium avium complex. 765 84


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