Role of bacille Calmette-Guérin in preventing tuberculous infection.

SETTING: Rural community in South India. OBJECTIVE: To determine the role of bacille Calmette-Guérin (BCG) in preventing tuberculous infection in children. DESIGN: A prevalence survey was undertaken in 1999-2001 in a representative rural population in Tiruvallur District in South India using cluster sampling. Tuberculin testing was performed among all children aged <15 years, and all adults aged 15 years were questioned about chest symptoms and underwent radiography, followed by sputum examinations, if indicated. RESULTS: In children living in households with a tuberculosis case, the proportion with evidence of tuberculous infection was 35.5% of 200 in the absence of a BCG scar and 27.0% of 100 in its presence, a reduction of 24% (P = 0.14). In very young children (age <5 years), the corresponding proportions were 29.1% of 55 and 11.9% of 42, a reduction of 59%; the difference was statistically significant (P = 0.048). CONCLUSION: There is a possible role for BCG in preventing tuberculous infection in very young children

Effects of body position on autonomic regulation of cardiovascular function in young, healthy adults

Background: Analysis of rhythmic patterns embedded within beat-to-beat variations in heart rate (heart rate variability) is a tool used to assess the balance of cardiac autonomic nervous activity and may be predictive for prognosis of some medical conditions, such as myocardial infarction. It has also been used to evaluate the impact of manipulative therapeutics and body position on autonomic regulation of the cardiovascular system. However, few have compared cardiac autonomic activity in supine and prone positions, postures commonly assumed by patients in manual therapy. We intend to redress this deficiency. Methods: Heart rate, heart rate variability, and beat-to-beat blood pressure were measured in young, healthy non-smokers, during prone, supine, and sitting postures and with breathing paced at 0.25 Hz. Data were recorded for 5 minutes in each posture: Day 1 - prone and supine; Day 2 - prone and sitting. Paired t-tests or Wilcoxon signed-rank tests were used to evaluate posture-related differences in blood pressure, heart rate, and heart rate variability. Results: Prone versus supine: blood pressure and heart rate were significantly higher in the prone posture (p &lt; 0.001). Prone versus sitting: blood pressure was higher and heart rate was lower in the prone posture (p &lt; 0.05) and significant differences were found in some components of heart rate variability. Conclusion: Cardiac autonomic activity was not measurably different in prone and supine postures, but heart rate and blood pressure were. Although heart rate variability parameters indicated sympathetic dominance during sitting (supporting work of others), blood pressure was higher in the prone posture. These differences should be considered when autonomic regulation of cardiovascular function is studied in different postures