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Biomedical subjects

R P Wagner

Publications and source records attributed to R P Wagner.

At least 19 recordsLinked to original sources
PubMed1996

AIDS-associated infections in salivary glands: autopsy survey of 60 cases.

We reviewed the autopsy findings for the submandibular glands of 60 patients with AIDS who were autopsied at the George Washington University Medical Center (Washington, DC) from 1982 to 1992. AIDS-associated infections in the submandibular glands were compared with those in the pancreas and lung. Cytomegalovirus intranuclear inclusions were found in 10 cases, and Pneumocystis carinii infection was found in one case. Disseminated mycobacterial and fungal infections were not identified in the submandibular gland, even in the presence of documented pancreatic and pulmonary infection (P < .05). Overall, the major salivary glands of patients with AIDS are less frequently involved with disseminated opportunistic infections than is either the lung or the pancreas (P < .01 and P < .001, respectively).

AIDS-Related Opportunistic Infections↗
PubMed1996

Phagocytosis and growth inhibition of Cryptococcus neoformans by human alveolar macrophages: effects of HIV-1 infection.

OBJECTIVE: The purpose of this study was to investigate the in vitro processing of Cryptococcus neoformans by human alveolar macrophages from HIV-seropositive individuals compared with HIV-seronegative individuals. DESIGN AND METHODS: Bronchalveolar lavage (BAL) was performed on smoking and nonsmoking HIV-seropositive and seronegative volunteers. Lavage cells from the four groups were challenged in vitro with C. neoformans and assessed for fungal binding, phagocytosis, and growth inhibition. RESULTS: The results indicated that BAL cells from the smoking HIV-infected group had increased fungistatic activity compared with HIV-seronegative smokers (mean percentage growth inhibition +/- SD, 77.5 +/- 14.2 versus 59.1 +/- 16.6%; P = 0.015). However, late-staged HIV-infected patients (Centers for Disease Control and Prevention class C3) were found to have decreased fungistasis compared with early stage A patients (63.8 +/- 11.1 versus 83.0 +/- 2.2%; P < 0.05). BAL cells recovered from HIV- seronegative smoking volunteers demonstrated reduced fungistatic activity when compared with BAL cells from HIV- seronegative nonsmokers (56.8 +/- 8.8 versus 83.0 +/- 2.2%; P < 0.001). Smoking also induced a decrease in internalization of C. neoformans by alveolar macrophages as assessed by confocal laser microscopy in both HIV-seronegative and HIV-infected groups. CONCLUSION: We conclude that BAL cells from early stage HIV-1-infected individuals do not have an intrinsic defect in fungistasis of C. neoformans. In fact, it appears that BAL cells from HIV-seropositive people are activated for fungistasis in early HIV infection, although fungistatic activity declines as the disease progresses. Incidentally noted was the finding that smoking decreases the internalization of C. neoformans in both HIV-infected and HIV-seronegative individuals, suggesting the possibility that smoking might enhance the susceptibility to cryptococcosis.

Cells, Cultured↗
PubMed1996

Interferon-gamma reduces the capacity of human alveolar macrophages to inhibit growth of Cryptococcus neoformans in vitro.

Cytokine stimulation of mouse and rat macrophages has previously been shown to enhance their capacity to phagocytose and inhibit the growth of Cryptococcus neoformans. To extend these observations to primary human macrophages, we investigated the anticryptococcal activity of human alveolar macrophages stimulated with interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), or macrophage-colony stimulating factor (M-CSF). Neither TNF-alpha nor M-CSF had any effect on fungal growth inhibition compared with unstimulated macrophages. Alveolar macrophages stimulated with IFN-gamma demonstrated reduced fungistasis for C. neoformans compared with controls (49% +/- 15% versus 75% +/- 12%; mean % growth inhibition +/- SD, P < 0.001). Confocal laser scanning microscopy was used to assess binding and phagocytosis of yeast. No difference was observed between unstimulated macrophages and macrophages stimulated with any of the cytokines tested. These data suggest that the cytokine regulation of anticryptococcal macrophage functions in humans differs from the rat and mouse. Conclusions drawn from these models may not necessarily be applicable to human cryptococcosis. In particular, the effects of IFN-gamma on the interaction of human alveolar macrophages with C. neoformans was not predicted based on the mouse and rat macrophage responses.

Animals↗
PubMed1995

Hospital and 1-year survival of patients admitted to intensive care units with acute exacerbation of chronic obstructive pulmonary disease.

OBJECTIVE: To describe outcomes and identify variables associated with hospital and 1-year survival for patients admitted to an intensive care unit (ICU) with an acute exacerbation of chronic obstructive pulmonary disease (COPD). DESIGN: Prospective, multicenter, inception cohort study. SETTING: Forty-two ICUs at 40 US hospitals. PATIENTS: A total of 362 admissions for COPD exacerbation selected from the Acute Physiology and Chronic Health Evaluation (APACHE) III database of 17,440 ICU admissions. MEASUREMENTS AND RESULTS: Hospital mortality for the 362 admissions was 24%. For the 167 patients aged 65 years or older, mortality was 30% at hospital discharge, 41% at 90 days, 47% at 180 days, and 59% at 1 year. Median survival for all patients was 224 days, and median survival for the patients who died within 1 year was 30.5 days. On multiple regression analysis, variables associated with hospital mortality included age, severity of respiratory and nonrespiratory organ system dysfunction, and hospital length of stay before ICU admission. Development of nonrespiratory organ system dysfunction was the major predictor of hospital mortality (60% of total explanatory power) and 180-day outcomes (54% of explanatory power). Respiratory physiological variables (respiratory rate, serum pH, PaCO2, PaO2, and alveolar-arterial difference in partial pressure of oxygen [PAO2-PaO2]) indicative of advanced dysfunction were more strongly associated with 180-day mortality rates (22% of explanatory power) than hospital death rates (4% of explanatory power). After controlling for severity of illness, mechanical ventilation at ICU admission was not associated with either hospital mortality or subsequent survival. CONCLUSIONS: Patients with COPD admitted to an ICU for an acute exacerbation have a substantial hospital mortality (24%). For patients aged 65 years or older, mortality doubles in 1 year from 30% to 59%. Hospital and longer-term mortality is closely associated with development of nonrespiratory organ system dysfunction; severity of the underlying respiratory function substantially influences mortality following hospital discharge. The need for mechanical ventilation at ICU admission did not influence either short- or long-term outcomes. Physicians should be aware of these relationships when making treatment decisions or evaluating new therapies.

APACHE↗
PubMed1992

HIV-1 envelope protein (gp120) inhibits the activity of human bronchoalveolar macrophages against Cryptococcus neoformans.

Cryptococcus neoformans infections are a major cause of morbidity and mortality for HIV-infected persons. Containment of the initial respiratory inoculation to the lung appears defective in patients with AIDS despite the low burden of HIV in bronchoalveolar macrophages. We have studied the fungistatic activity of human bronchoalveolar macrophages (BAM) cultured with an encapsulated strain of C. neoformans in the presence of pooled human serum. We observed 51.6% fungistasis after 24 h of culture. Fungistasis was diminished if the pooled human serum was heat-inactivated but was not affected by anticryptococcal capsular IgG. HIV envelope protein (gp120) has been shown to interfere with lymphocyte activation in vitro. We studied the effects of gp120 on BAM function and found that fungistatic activity was inhibited 25% (p < 0.001). Although binding of yeasts was not affected, gp120 inhibited the internalization of bound yeasts by 46% (p = 0.025). These experiments indicate that gp120 decreases the internalization and fungistasis of C. neoformans by human BAM, and they suggest a mechanism to explain how a small number of HIV-1-infected cells in the lung could impair the containment of C. neoformans.

Bronchoalveolar Lavage Fluid↗
PubMed1985

A coordinate relationship between the GALK and the TK1 genes of the Chinese hamster.

Chinese hamster cells in culture were treated with various concentrations of thymidine, 5-bromodeoxyuridine, trifluorothymidine, and 2-deoxy-D-galactose. Selection was made for deficiencies in the activities of galactokinase and thymidine kinase. Selection in the presence of thymidine, 5-bromodeoxyuridine, and trifluorothymidine was expected to produce clones deficient in thymidine kinase only, whereas those deficient in galactokinase were expected to be selected in the presence of 2-deoxy-D-galactose. However, it was found that clones growing in the presence of these inhibitors were frequently deficient in both enzymes. Or if a clone was deficient in only one, the deficiency frequently was not expected according to the selection procedure. This indicates some sort of coordinate relationship between the two gene loci, GALK and TK1, which specify galactokinase and thymidine kinase, respectively. GALK and TK1 are linked in all primates and rodents in which linkage determinations have been made. It is therefore probable that this linkage has been conserved for a long period of time. It is suggested that the apparent relationship between the two genes shown by the data presented here, as well as by others, supports the conclusion that linkage has been conserved by natural selection and is therefore not fortuitous.

Animals↗
PubMed1984

Thymidine-kinase activity of cultured cells from individuals with inherited galactokinase deficiency.

Cells of a person homozygous for galactokinase deficiency and of her heterozygous parents were found to be deficient in the enzyme thymidine kinase. The decrease in thymidine-kinase activity may be the result of a qualitative alteration in the enzyme molecule. This is reflected in the apparent alteration in the sensitivity of the enzyme to trifluorothymidine. It is suggested that this relationship between the galactokinase and thymidine kinase is not fortuitous but a reflection of their interdependence as found previously in the Chinese hamster.

Alleles↗
PubMed1975

Two forms of a mitochondrial endonuclease in Neurospora crassa.

Mitochondrial nuclease activity in Neurospora crassa occurs in membrane-bound and soluble forms in approximately equal proportions. These activities apparently are due to the same enzyme, which has an approximate molecular weight of 120 000. A portion of the insoluble enzyme appears to be associated with the inner mitochondrial membrane and is resistant to solubilization by detergent treatment as well as by physical disruption methods.

Cytochrome Reductases↗
PubMed1974

A pyruvate-valine enzyme complex that is dependent upon the metabolic state of the mitochondria.

Data are presented suggesting that intact Neurospora crassa mitochondria contain an enzyme complex incorporating five enzymes necessary for the biosynthesis of isoleucine and valine. The functional integrity and stability of the complex has been shown to be dependent on the metabolic state of the mitochondria. The complex has been solubilized by digitonin and has an approximate molecular weight of 400,000.

Carbon Radioisotopes↗