Adjusted subpixel method enables optimisation of bronchial measurements in high-resolution CT.

OBJECTIVES: The purpose of this paper is to present a new technique of high-resolution computed tomography (HRCT) bronchial measurement, which was worked out in our centre and is based on a mathematically adjusted subpixel method (ASM). METHODS: This study used a bronchial tree model comprising two polyvinyl chloride/rubber pipes with various densities placed in a larger plastic object. External and internal diameters of both pipes corresponded to the sizes of structures that are usually evaluated in HRCT scans (i.e. the bronchus with accompanying blood vessel). The model was subjected to repeated HRCT measurements of the external and internal diameters of model pipes using a subpixel technique and ASM. RESULTS: Significant differences were observed between mean values of external and internal diameters of model pipes determined by means of subpixel method or ASM, with the latter being the ones that resembled real diameters of the model pipes more closely. Mean external diameters of the larger and smaller model pipes determined by ASM differed from the real diameters by 0.23% and 0.57%, respectively. The internal diameter of the larger pipe was on average 25.96% larger, whereas the internal diameter of the smaller pipe was 48.05% smaller than the real diameter. CONCLUSION: The technique of non-linear prediction of HRCT bronchial measurements described in this paper raises attractive prospects in its clinical application owing to potential improvements in the objectivity and reproducibility of bronchial wall measurements.

Maternal smoking decreases antioxidative status of human breast milk.

OBJECTIVE: To evaluate the influence of maternal smoking on antioxidative capacity and intensity of oxidative damage in breast milk. STUDY DESIGN: The study group (n=30) was comprised of postpartum women who declared smoking more than five cigarettes per day during pregnancy and lactation (confirmed by the urinalysis of cotinine concentration), and their newborns. Control group included 29 non-smoking postpartum women and their newborns. Colostrum samples were collected on the 3rd day after delivery and breast milk samples between the 30th and the 32nd day after delivery. Morning maternal and neonatal urine samples were obtained on the day of the mature milk sampling. Isoprostane concentrations in colostrum/mature milk and urine were determined immunoenzymatically. Total Antioxidant Status (TAS) of colostrum/breast milk was determined by Rice-Evans and Miller method. RESULT: Colostrum TAS in smokers was significantly lower than in non-smokers (P=0.006). In both groups, the TAS of mature milk was higher compared with colostrum, but significant differences were observed amongst smokers only (P=0.001). In smokers the isoprostane concentration of mature milk was significantly higher than the colostrum concentration (P=0.001). Significant inverse correlation between maternal urinary isoprostane concentration and the TAS of mature breast milk was observed in smokers (R=-0.525, P=0.023), but not in non-smokers (R=0.161, P=0.422). CONCLUSION: This study revealed that maternal smoking triggers harmful effects on an infant by impairing pro-oxidant-antioxidant balance of breast milk.