Aerosolised 5-azacytidine suppresses tumour growth and reprogrammes the epigenome in an orthotopic lung cancer model.

BACKGROUND: Epigenetic silencing by promoter methylation and chromatin remodelling affects hundreds of genes and is a causal event for lung cancer. Treatment of patients with low doses of the demethylating agent 5-azacytidine in combination with the histone deacetylase inhibitor entinostat has yielded clinical responses. The subcutaneous dosing route for consecutive days and reduced bioavailability of 5-azacytidine because of inactivation by cytidine deaminase may limit the expansion of epigenetic therapy into Phase III trials. To mitigate these barriers, an aerosol of 5-azacytidine was generated and characterised. METHODS: The effect of aerosol vs systemic delivery of 5-azacytidine on tumour burden and molecular response of engrafted lung tumours in the nude rat was compared. RESULTS: Pharmacokinetics revealed major improvement in the half-life of 5-azacytidine in lung tissue with aerosol delivery. Aerosolised 5-azacytidine significantly reduced lung tumour burden and induced global demethylation of the epigenome at one-third of the comparable effective systemic dose. High commonality for demethylation of genes was seen in tumours sampled throughout lung lobes and across treated animals receiving the aerosolised drug. CONCLUSION: Collectively, these findings show that aerosolised 5-azacytidine targets the lung, effectively reprogrammes the epigenome of tumours, and is a promising approach to combine with other drugs for treating lung cancer.

Predicting gene promoter methylation in non-small-cell lung cancer by evaluating sputum and serum.

The use of 5-methylcytosine demethylating agents in conjunction with inhibitors of histone deacetylation may offer a new therapeutic strategy for lung cancer. Monitoring the efficacy of gene demethylating treatment directly within the tumour may be difficult due to tumour location. This study determined the positive and negative predictive values of sputum and serum for detecting gene methylation in primary lung cancer. A panel of eight genes was evaluated by comparing methylation detected in the primary tumour biopsy to serum and sputum obtained from 72 patients with Stage III lung cancer. The prevalence for methylation of the eight genes in sputum (21-43%) approximated to that seen in tumours, but was 0.7-4.3-fold greater than detected in serum. Sputum was superior to serum in classifying the methylation status of genes in the tumour biopsy. The positive predictive value of the top four genes (p16, DAPK, PAX5 beta, and GATA5) was 44-72% with a negative predictive value for these genes > or =70%. The highest specificity was seen for the p16 gene, and this was associated with a odds ratio of six for methylation in the tumour when this gene was methylated in sputum. In contrast, for serum, the individual sensitivity for all genes was 6-27%. Evaluating the combined effect of methylation of at least one of the four most significant genes in sputum increased the positive predictive value to 86%. These studies demonstrate that sputum can be used effectively as a surrogate for tumour tissue to predict the methylation status of advanced lung cancer where biopsy is not feasible.

TB control in the hospital environment.

Tuberculosis is again on the rise in the United States. Several outbreaks of TB in hospitals have heightened interest in the development and use of mechanisms that prevent the spread of this airborne pathogen. Controlling the spread of TB to hospital patients, workers, and others can be accomplished through various administrative engineering and design controls, and infection control programs, as recommended by the Centers for Disease Control and Prevention (CDC). The hazard of TB is real, but workers, patients, and visitors can be protected by implementing programs that guard against the diseases spread in the hospital environment.

Health advocacy for young, low-income, inner-city women.

The Urban Women's Health Advocacy Training Project was a university-based demonstration program designed to collect data on the health status of urban women and to test nursing interventions for training community health advocates. Thirty Hispanic and black trainees between 17 and 21 years of age were selected to participate in an eight-week, 20-h/w program emphasizing women's health education, health advocacy skills, and career awareness. This project has many implications for nursing practice with young, inner-city women. Enhancing the self-care and advocacy skills of these women maximizes their potential for use of available health services and their ability to influence the expansion of the services required to meet their own and their families' health care needs. Problems in funding and conducting such demonstration projects are discussed.

Human overdose with the veterinary tranquilizer xylazine.

Three patients self-injected the veterinary tranquilizing agent xylazine (Rompun). The first patient developed mild bradycardia and hypotension, miosis, and a feeling of disorientation. The other two patients became apneic and required intubation and mechanical ventilation. Initial mild hypertension followed by mild hypotension and a mildly elevated blood glucose was seen in the second patient, whereas both the second and third patients developed mild bradycardia. Xylazine has structural similarity to the phenothiazines and pharmacological activity similar to clonidine. With increasing veterinary use, the availability and potential for human exposures may also increase.

Ultrastructural correlates of transmitter release in presynaptic areas of lamprey reticulospinal axons.

The ultrastructure of presynaptic areas of lamprey reticulospinal axons was studied before, during, and after periods of elevated transmitter release produced either by repetitive action potential activity or depolarization by elevated extracellular potassium. Controls for possible effects of these procedures per se were done by replacing extracellular Ca with Mg to block transmitter release. In some experiments the time course of ultrastructural changes during K depolarization and subsequent recovery were studied by fixing tissue samples at various times. Transmitter release produced by action potential activity (20/sec for 15 min) in the presence of extracellular Ca significantly and reversibly decreased the number of synaptic vesicles, the area occupied by the vesicles, and the density of synaptic vesicles. An unexpected finding was a reversible decrease in the length of the differentiated membrane during periods of increased transmitter release. Transmitter release significantly and reversibly increased the number of coated vesicles, expanded the presynaptic membrane, and increased the number of pleomorphic vesicles. K depolarization (50 mM K for 15 min) produced identical, reversible effects, except that the expansion of the presynaptic membrane, although significant, was relatively small and there was no change in the number of pleomorphic vesicles. Raising the temperature of the saline from 2 degrees C (K depolarization experiments) or 7 degrees C (action potential experiments) to 20 degrees C did not change the results qualitatively but did produce somewhat larger effects during stimulation and appeared to increase the speed of recovery. Action potential activity or K depolarization in control experiments with the Ca in the saline replaced by Mg had little or no effect on synaptic ultrastructure. Synaptic vesicles in lamprey reticulospinal axons never contacted the axonal membrane anywhere other than at the differentiated membrane. During periods of elevated transmitter release, although the absolute number of vesicles in contact with the differentiated membrane decreased, the percentage of total vesicles in contact with the differentiated membrane increased dramatically. This suggests that the differentiated membrane is the site of vesicle release and there is an active process of vesicle movement to this membrane. In the course of this work it was observed that presynaptic areas closer than approximately 2 mm to the site of axonal transection, regardless of the composition of the saline or the experimental conditions, showed ultrastructural changes typical of increased transmitter release.(ABSTRACT TRUNCATED AT 400 WORDS)