Endogenous nitric oxide in exhaled air from patients with liver cirrhosis.

BACKGROUND: The aim of this study was to investigate the potential effects of liver insufficiency on nitric oxide concentrations in exhaled air. METHODS: Nitric oxide concentrations in the exhaled air from 13 patients with liver cirrhosis and 11 healthy control subjects was examined by the single-breath technique. RESULTS: There was a clear correlation between Child-Pugh score and NO in exhaled air (peak after 15 sec of breathholding, R = 0.623, P = 0.023). Similarly, there were significant correlations in peak NO concentrations and alkaline phosphatase, bilirubin, aspartate and alanine aminotransferase, and albumin. The most severely ill patient in our study had the highest NO concentrations in her exhaled air. On recovery from her liver illness the concentration of NO in her exhaled air decreased. There was no correlation between circulating levels of the endogenous NO synthase inhibitors asymmetric and symmetric N(G), N(G)-dimethyl-arginine and exhaled NO concentrations. CONCLUSIONS: The present data show a correlation between endogenous NO formation in the respiratory system and liver dysfunction. This might contribute to the understanding of the pathophysiology in pulmonary vasodilatation in liver disease.

Visualisation of nitric oxide released by nerve stimulation.

We have visualised nitric oxide (NO) released from the electrically stimulated myenteric plexus and hypogastric nerve. NO was visualised by a reaction with luminol and hydrogen peroxide to generate photons which were counted using a microscope coupled to a photon counting camera. Electrical stimulation of the tissues induced an increase in photon counts which was frequency-dependent and prevented by inhibition of the NO synthase or by tetrodotoxin. The light emitted during nerve stimulation was not only observed at the nerve terminals but also at the axon and soma. Our results indicate that NO released from the whole nerve cell may affect target cells surrounding all parts of the nitrergic neuron. Thus, NO functions as a unique mechanism of synaptic and non-synaptic communication in the nervous system.

Visualisation of nitric oxide generated by activated murine macrophages.

We have visualised the release and approximate diffusion profile of nitric oxide (NO) from activated murine macrophages using a high transmission microscope coupled to a high sensitivity photon counting camera. The images generated by NO were cell-associated and spread over an area of approximately 175 micrometers from the activated macrophage. The signals obtained were dependent on the presence of exogenous L-arginine in the medium and followed a time course similar to that previously described for the generation of NO by the inducible form of NO synthase. The light signal was attenuated by the inhibitor of NO synthase, N omega-nitro-L-arginine methyl ester. Studies using superoxide-deficient macrophages further confirmed that the signals detected were generated by NO rather than reactive oxygen intermediates.

A simple and rapid method for the detection and identification of mycobacteria using mycobactin.

A system was developed for the identification of mycobacteria such as Mycobacterium tuberculosis and M. avium, by thin layer chromatography of 55Fe-labelled mycobactin. Approximately 2 x 10(3) mycobacteria were detected within 24 h and little operator time or skill was required. M. avium, M. intracellulare and M. scrofulaceum were found to have lower requirements for iron than other mycobacteria and this may influence their growth in host organisms.

Isolation of Protomonas extorquens (the 'red phantom') from a patient with AIDS.

We report the isolation of a pigmented, slowly growing, environmental organism with pink colonies from the blood of a patient with AIDS. The organism was characterised biochemically and by protein 'fingerprinting' as Protomonas extorquens biovar 3. This is the first report of isolation of this organism from a patient with AIDS.