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Bacterial pneumonia remains a significant cause of patient morbidity and mortality worldwide. Pulmonary surfactant serves to maintain homeostasis in the lung through the maintenance of alveolar stability and the regulation of the alveolar immune response. The purpose of this study was to characterize the lung injury and associated surfactant alterations in a rat model of acute Pseudomonas aeruginosa pneumonia. Pneumonia was induced in male Sprague-Dawley rats via intratracheal injection of 0.2 ml, phosphate-buffered saline (PBS) containing P. aeruginosa (6x10(8) colony-forming units x mL(-1)). Control animals received 0.2 mL sterile PBS. Twenty-four hours after inoculation, the pneumonia group (PN) exhibited clinical signs of pneumonia including deficits in gas exchange, leukopenia and elevated arterial lactate levels. Morphological assessment confirmed the presence of pneumonia with airspaces filled with polymorphonuclear cells. Lung homogenate analysis demonstrated evidence of bacterial colonization of pneumonic lung tissue. Lung compliance was also significantly lower in the PN group. Lung lavage analysis of PN rats revealed the pooled surfactant levels to be lower and the surfactant function reduced compared to control rats. Surfactant composition was also found to be altered in PN rats. These results demonstrate that in Pseudomonas aeruginosa pneumonia, the pulmonary surfactant system is both poorly functioning and reduced in quantity. These alterations may contribute to the lung dysfunction characteristic of this disorder.

To evaluate the role of nitric oxide (NO) in the attenuated vascular reactivity observed in sepsis, we utilized the specific NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). Male Sprague-Dawley rats (n = 16) were randomized to either sepsis induced by cecal ligation and perforation (CLP; n = 8) or sham procedure (Sham; n = 8). Vascular reactivity was assessed by measuring the pulmonary pressor response to hypoxia (HPV) (fractional inspired O2 concentration = 0.08) and the pulmonary and systemic pressor response to an intravenous infusion of phenylephrine (1.5-6.0 micrograms.kg-1.min-1). Twenty-four hours after surgery, CLP animals had significantly attenuated HPV compared with Sham animals. In response to hypoxia the change in total pulmonary vascular resistance during hypoxia was 0.008 +/- 0.004 and 0.021 +/- 0.006 mmHg.min-ml-1 in CLP and Sham animals, respectively (P < 0.05). The pulmonary and systemic blood pressure response to phenylephrine was also attenuated in CLP compared with Sham animals. After L-NAME infusion (15 mg/kg), there was a significant augmentation of the HPV response in Sham animals. In contrast, the HPV response in CLP animals was unchanged after L-NAME. The attenuated pressor response to phenylephrine in neither the pulmonary nor the systemic circulation was changed after the administration of L-NAME. These data suggest that in rats, excess NO is not an important mediator of the attenuated vascular reactivity observed in sepsis.

Infection with the human immunodeficiency virus (HIV) results in a chronic systemic illness with multi-organ involvement, severe immunosuppression and profound cachexia. It has had a major impact on women's health. Endocrine abnormalities may contribute to the clinical presentation and therefore appropriate treatment would theoretically improve the patient's condition. This pilot study was undertaken to assess the endocrine status in a group of HIV seropositive women with the view to developing recommendations for future investigations. Thirteen women were recruited from a clinic for HIV-infected patients. All women had a comprehensive general and gynecological examination. Basal endocrine status was assessed and combined pituitary testing with gonadotropin-releasing hormone, thyrotropin-releasing hormone, growth hormone-releasing hormone and corticotropin-releasing hormone was performed. None of the participating women presented with gynecological complaints or had symptoms suggestive of an endocrinopathy. On questioning, seven women complained of menstrual abnormalities. Three had a body mass index of less than 20 kg/m2. Genital tract infections were common. Endocrine assessment demonstrated abnormalities of the pituitary-adrenal, pituitary-thyroid and pituitary-ovarian axes in seven women. One woman had panhypopituitarism. In six of the seven affected women CD4 counts were below 200 cells/mm3. Alterations in endocrine function were observed in seven of the women tested. While routine endocrine testing may not be indicated in all HIV-seropositive women, we should be aware of possible subtle presentations of endocrine abnormalities which may require treatment, especially in stress situations.

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