HIV as a chronic disease: implications for long-term care at an AIDS-dedicated skilled nursing facility.

OBJECTIVE: To describe the characteristics and outcomes of the first 3 years of admissions to a dedicated skilled nursing facility for people with acquired immunodeficiency syndrome (AIDS). METHODS: Systematic chart review of consecutive admissions to a 30-bed, AIDS-designated long-term care facility in New Haven, Connecticut, from October 1995 through December 1998. RESULTS: The facility has remained filled to 90% or more of its bed capacity since opening. Of 180 patients (representing 222 admissions), 69% were male; mean age was 41 years; 57% were injection drug users; 71% were admitted directly from a hospital. Leading reasons for admission were (1) the need for 24-hour nursing/medical supervision, (2) completion of acute medical treatment, and (3) terminal care. On admission, the median Karnofsky score was 40, and median CD4+ cell count was 24/mm3; 48% were diagnosed with serious neurologic disease, 44% with psychiatric illness; patients were receiving a median of 11 medications on admission. Of 202 completed admissions, 44% of patients died, 48% were discharged to the community, 8% were discharged to a hospital. Median length of stay was 59 days (range 1 to 1,353). Early (< or = 6 months) mortality was predicted by lower admission CD4+ count, impairments in activities of daily living, and the absence of a psychiatric history; long-term stay (> 6 months) was predicted by total number of admission medications, neurologic disease, and dementia. Comparison of admissions from 1995 to 1996 to those in 1997 to 1998 indicated significantly decreased mortality rates and increased prevalence of psychiatric illness between the two periods (P < .01). CONCLUSIONS: A dedicated skilled nursing facility for people with AIDS can fill an important service need for patients with advanced disease, acute convalescence, long-term care, and terminal care. The need for long-term care may continue to grow for patients who do not respond fully to current antiretroviral therapies and/or have significant neuropsychiatric comorbidities. This level of care may be increasingly important not only in reducing lengths of stay in the hospital, but also as a bridge to community-based residential options in the emerging chronic disease phase of the AIDS epidemic.

Determination of the contribution of cysteinyl leukotrienes and leukotriene B4 in acute inflammatory responses using 5-lipoxygenase- and leukotriene A4 hydrolase-deficient mice.

Arachidonic acid metabolism by 5-lipoxygenase leads to production of the potent inflammatory mediators, leukotriene (LT) B4 and the cysteinyl LT. Relative synthesis of these subclasses of LT, each with different proinflammatory properties, depends on the expression and subsequent activity of LTA4 hydrolase and LTC4 synthase, respectively. LTA4 hydrolase differs from other proteins required for LT synthesis because it is expressed ubiquitously. Also, in vitro studies indicate that it possesses an aminopeptidase activity. Introduction of cysteinyl LT and LTB4 into animals has shown LTB4 is a potent chemoattractant, while the cysteinyl LT alter vascular permeability and smooth muscle tone. It has been impossible to determine the relative contributions of these two classes of LT to inflammatory responses in vivo or to define possible synergy resulting from the synthesis of both classes of mediators. To address this question, we have generated LTA4 hydrolase-deficient mice. These mice develop normally and are healthy. Using these animals, we show that LTA4 hydrolase is required for the production of LTB4 in an in vivo inflammatory response. We show that LTB4 is responsible for the characteristic influx of neutrophils accompanying topical arachidonic acid and that it contributes to the vascular changes seen in this model. In contrast, LTB4 influences only the cellular component of zymosan A-induced peritonitis. Furthermore, LTA4 hydrolase-deficient mice are resistant to platelet-activating factor, identifying LTB4 as one mediator of the physiological changes seen in systemic shock. We do not identify an in vivo role for the aminopeptidase activity of LTA4 hydrolase.

Deficiency of 5-lipoxygenase abolishes sex-related survival differences in MRL-lpr/lpr mice.

Leukotrienes, the 5-lipoxygenase (5LO) products of arachidonic acid metabolism, have many proinflammatory actions that have been implicated in the pathogenesis of a variety of inflammatory diseases. To investigate the role of LTs in autoimmune disease, we generated an MRL-lpr/lpr mouse line with a targeted disruption of the 5lo gene. MRL-lpr/lpr mice spontaneously develop autoimmune disease that has many features resembling human systemic lupus erythematosus, including sex-related survival differences; female MRL-lpr/lpr mice experience significant early mortality compared with males. Unexpectedly, we found that mortality was accelerated in male 5LO-deficient MRL-lpr/lpr mice compared with male wild-type MRL-lpr/lpr animals. In contrast, the 5lo mutation had no effect on survival in females. Mortality was also accelerated in male MRL-lpr/lpr mice that were treated chronically with a pharmacological inhibitor of LT synthesis. Furthermore, LT-dependent inflammatory responses are enhanced in male MRL-lpr/lpr mice compared with females, and the 5lo mutation has greater impact on these responses in males. Because immune complex-mediated glomerulonephritis is the major cause of death in MRL-lpr/lpr mice and has been related to arachidonic acid metabolites, we also assessed kidney function and histopathology. In male MRL-lpr/lpr mice, renal plasma flow was significantly reduced in the 5lo-/- compared with the 5lo+/+ group, although there were no differences in the severity of renal histopathology, lymphoid hyperplasia, or arthritis between the groups. These findings suggest that the presence of a functional 5lo gene confers a survival advantage on male MRL-lpr/lpr mice and that, when 5LO function is inhibited, either genetically or pharmacologically, this advantage is abolished.

Altered inflammatory responses in leukotriene-deficient mice.

Leukotrienes have been implicated in the regulation of immune responses, including inflammation and immediate hypersensitivity reactions. Here, we describe the phenotypic analysis of leukotriene-deficient mice generated by inactivation of the 5-lipoxygenase (5LO) gene. These 5LO(-/-) mice were unable to synthesize detectable levels of leukotrienes and were more resistant to lethal anaphylaxis induced by platelet-activating factor. The intensity of an acute inflammatory response induced by arachidonic acid was similar in 5LO(-/-) mice and controls. However, the response in 5LO(-/-) mice, but not in controls, could be virtually eliminated by a cyclooxygenase inhibitor. These data suggest that inflammatory responses are modulated by arachidonic acid metabolites through a variety of interconnected mechanisms. This has important implications for understanding the early events of an inflammatory response and for designing drugs for use in therapeutic intervention.