Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Early in the developmental period of microbiology, Pasteur first observed the phenomenon of dimorphism in fungi when he noticed that the bread mold Mucor grew as a filamentous mold aerobically on the surface of broth cultures but at the bottom of the flask where the environment was anaerobic it reproduced as budding yeast cells. Several infectious fungal pathogens of humans, namely Histoplasma capsulatum, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Sporothrix schenkii, and Coccidioides immitis change from a multicellular filamentous form to an unicellular morphology when they invade tissues. The ability of pathogenic fungi to assume a different shape is referred to as dimorphism. This phenomenon has intrigued clinicians, and medical mycologists since its discovery at the turn of the century. The ability of pathogens to initiate infection, invade host tissues and survive in mammalian hosts is critically linked to the induction of specific gene products. In dimorphic fungi, developmentally regulated gene expression is particularly important, since they may exist in phylogenetically distinct hosts with different body temperatures. Using Histoplasma capsulatum as a model to study parasite-host interactions at the biochemical and molecular level, my laboratory has attempted to relate the clinical spectrum of disease to natural variations in the characteristics of this organism and to adaptations it must make as a saprobe and a parasite. Histoplasma capsulatum is the etiologic agent of histoplasmosis, a respiratory infection that is world-wide in distribution. As a saprobe in soil it is mycelial, but it becomes a budding yeast as a parasite in susceptible hosts. These morphological phases can be reversibly reproduced in vitro by shifting the temperature from 25 degrees C, at which it is mycelial, to 37 degrees C, when it becomes a budding yeast. The process of mycelial-to-yeast conversion is of particular interest since it is triggered by an increase in temperature and conversion to virulence. Viable mycelial fragments and conidia become airborne and enter the pulmonary tract by inhalation after which the fungus rapidly disseminates to other organs. Progressive disseminated histoplasmosis along with candidiasis, cryptococcosis, and invasive aspergillosis are opportunistic fungal infections in patients who are immunosuppressed or otherwise debilitated. Importantly, they are diagnostic hallmarks of acquired immunodeficiency disease syndrome (AIDS). The clinical features of these infections and the genetic characteristics of the etiologic agents present unique parasite-host interactions that make them valuable research models to study. In the infected host, Histoplasma capsulatum encounters various environmental stresses to which it adapts by regulating the expression of specific genes.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Unraveling the secrets of Histoplasma capsulatum. A model to study morphogenic adaptation during parasite host/host interaction. 757 55

Four patients were diagnosed with reactive hemophagocytic syndrome (RHPS) during a 7 month period. Of these, three patients were diagnosed with acquired immunodeficiency syndrome complicated by disseminated Mycobacterium tuberculosis infection, incompletely treated Pneumocystis carinii pneumonia and disseminated histoplasmosis respectively. The fourth patient had non-Hodgkin's lymphoma of the mature T-cell phenotype. Fever, bicytopenia, or pancytopenia, elevated serum lactate dehydrogenase (LDH) level (> 1,000 IU/L), and hemophagocytic histiocytosis in smears of bone marrow aspirate were present in all patients. Hyperferritinemia (> 10,000 ng/ml) was present in all (range 34,976 to 425,984 ng/mL) and showed a decrease in the two patients who responded to therapy. Hyperferritinemia (> 10,000 ng/ml) and elevated serum LDH (> 1,000 IU/L) are important clues to the diagnosis of RHPS in the febrile cytopenic patient with immunodeficiency.
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PMID:Hyperferritinemia in reactive hemophagocytic syndrome report of four adult cases. 760 19

Surgical consultation is regularly requested for diagnosis and treatment of pulmonary complications of the endemic mycosis, Histoplasma capsulatum, Blastomyces dermatitidis and Coccidioidomycosis immitis, and the yeast Cryptococcus neoformans. All resemble pulmonary malignancies. Histoplasmosis causes pericarditis, mediastinal fibrosis and mediastinal granuloma, which can cause entrapment of vascular structures, the esophagus, and the trachea. Coccidioidomycosis can cause spontaneous pneumothorax and thin wall cavities that can be superinfected with tuberculosis and Aspergillosis. The pathogenesis, diagnosis, and treatment of these organisms are discussed with emphasis on the new oral therapies and complications encountered in persons with human immunodeficiency virus (HIV) infection.
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PMID:The endemic mycoses: surgical considerations. 761 61

From 1989 to 1994, 71 patients were hospitalized for diagnosis of round lung lesions including 49 servicemen under the age of 45 years who had been stationed in tropical areas. In 6 of these servicemen, the diagnosis was pulmonary histoplasmosis at the tertiary stage of histoplasmoma. All had done duty in French Guyana and were negative for human immunodeficiency virus. The subpleural lung opacity was the only lesion in 5 out of 6 patients and was calcified in 4 out of 6 patients. Since skin tests with histoplasmin and serologic testing for histoplasmosis failed to achieve definitive diagnosis, surgical biopsy was performed by conventional thoracotomy in 2 cases and video-assisted thoracic surgery in 4 cases. The specimens obtained confirmed diagnosis of histoplasmosis on mycologic criteria in 3 cases and on a combination of findings including compatible histologic evidence in 3 cases. Treatment consisted in surgical excision of the nodules, for which video-assisted thoracoscopic surgery proved to be an excellent technique because of its simplicity and rapidity.
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PMID:[Round pulmonary lesions after returning from French Guyana. Six cases of american pulmonary histoplasmosis]. 763 11

Within the upper aerodigestive tract, histoplasmosis often mimics carcinoma, making prompt and accurate diagnosis imperative. More severe and potentially lethal infections with Histoplasma capsulatum are now being seen as the numbers of patients at the extremes of age, as well as those with compromised immune systems, increase. We reviewed the cases of 115 hospitalized patients with disseminated histoplasmosis. Of these, 9 patients were identified with otolaryngologic manifestations: 4 were infected with human immunodeficiency virus (HIV), 1 was diabetic, and 3 were renal transplant patients. Sites of involvement included the larynx (in 2 cases) and the oral cavity and oral pharynx (in 7 cases). Eight of the 9 patients had a positive biopsy result; the other, a positive culture. Treatment with amphotericin B was generally effective, while the use of newer azole anti-fungal agents were less effective. As the number of immunocompromised patients continues to increase in modern clinical practice, histoplasmosis will undoubtedly be encountered more frequently in the head and neck area.
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PMID:Histoplasmosis: the otolaryngologist's perspective. 766 25

A 39-year-old woman infected with human immunodeficiency virus had disseminated histoplasmosis that presented with nodules on her tongue. This is the seventh reported case of biopsy- and/or culture-proven oropharyngeal histoplasmosis in patients with acquired immunodeficiency syndrome. We review those previous reports and discuss the clinical features of disseminated histoplasmosis in patients with acquired immunodeficiency syndrome.
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PMID:Disseminated histoplasmosis presenting as tongue nodules in a patient infected with human immunodeficiency virus. 772 54

The phagocytic and fungistatic activity of monocyte-derived macrophages from human immunodeficiency virus (HIV)-positive persons against Histoplasma capsulatum yeasts was determined. Macrophages from HIV-positive patients were profoundly deficient in their capacity to recognize and bind H. capsulatum, but ingestion of bound yeasts was normal. The binding of H. capsulatum by patient macrophages tended to decrease with a decrease in CD4+ T lymphocyte counts. Another major defect was that patient macrophages were more permissive for the intracellular growth of H. capsulatum. Macrophages from 22 of 58 patients showed a > or = 2-fold increase in intracellular growth compared with control macrophages. Thus, in addition to defects in cell-mediated immunity caused by a loss of CD4+ T cells, macrophages from HIV-positive patients exhibit intrinsic defects in macrophage function against H. capsulatum that may contribute to the increased susceptibility of HIV-positive patients to disseminated histoplasmosis.
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PMID:Macrophages from human immunodeficiency virus-positive persons are defective in host defense against Histoplasma capsulatum. 784 67

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

Two hemophiliacs infected with human immunodeficiency virus (HIV) presented with hematochezia secondary to gastrointestinal involvement with Histoplasmosis capsulatum. In one patient who was already receiving fluconazole, the diagnosis was obscured. Both patients responded to amphotericin B followed by intraconazole, with no recurrence of bleeding.
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PMID:Gastrointestinal histoplasmosis presenting as hematochezia in human immunodeficiency virus-infected hemophilic patients. 794 89

In the 1960s and 1970s, amphotericin B was the only effective therapy for serious systemic endemic fungal infections due to Histoplasma capsulatum, Blastomyces dermatitidis, and Sporothrix schenckii. In the 1980s, ketoconazole was introduced as therapy for endemic mycoses; after this antifungal agent was introduced, some of these infections could be treated orally in an outpatient setting rather than intravenously in an inpatient setting. The 1990s have become the triazole era. It is now standard practice to treat nonmeningeal, non-life-threatening histoplasmosis and blastomycosis orally on an outpatient basis; the drug of choice for this treatment is itraconazole. Itraconazole also has proved useful as treatment for histoplasmosis in patients infected with human immunodeficiency virus. Although itraconazole has not yet been approved for the treatment of sporotrichosis, in preliminary studies it has been shown to be effective therapy not only for cutaneous and lymphocutaneous sporotrichosis but also for disseminated infection with S. schenckii.
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PMID:Newer developments in therapy for endemic mycoses. 794 68


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