Circulation in the breast after radiotherapy and breast conservation.

OBJECTIVE: To investigate the breast circulation after radiotherapy and breast conservation. DESIGN: Open clinical study. SETTING: University hospital, Sweden. SUBJECTS: 24 patients with breast cancer (mean age 54 years, range 41-64). INTERVENTIONS: The glandular and the subcutaneous circulation in the breast were measured by Xenon (133Xe) clearance and the skin circulation by laser Doppler fluxmetry (LDF) two to five years after radiotherapy (50 Gy) following lumpectomy. The subcutaneous circulation was measured 2 cm above and medial or lateral to the areolar border and the glandular circulation 2 cm below and medial or lateral to the areolar border in the quadrant not previously operated on for carcinoma. The skin circulation was measured at the corresponding sites. MAIN OUTCOME MEASURES: Circulation in the subcutaneous and glandular tissue measured by 133Xe clearance and in the skin by LDF. RESULTS: The subcutaneous circulation, expressed as the ratio of 133Xe clearance in the operated irradiated: non-operated non-irradiated breast, was 0.88 (0.94) (median, interquartile range) and the glandular circulation 0.93 (0.75). The skin circulation ratios over the corresponding areas were 1.00 (0.37) and 1.00 (0.38), respectively. CONCLUSION: Radiotherapy after breast conservation surgery does not lead to long-term changes in basal glandular, subcutaneous, or skin circulation in the breast.

Incidence and geographical distribution of sudden infant death syndrome in relation to content of nitrate in drinking water and groundwater levels.

BACKGROUND: Previous studies indicate that the enteral bacterial urease is inhibited in victims of sudden infant death syndrome (SIDS). One possible inhibitor of this bacterial activity is nitrate. If ambient pollution by nitrate is involved in the etiology of SIDS only a fraction of the nitrate concentration not infrequently found in drinking water would be enough for this inhibition. METHODS: Occurrence of SIDS (n = 636) in Sweden during the period 1990 through 1996 were analysed regarding geographical and seasonal distribution in relation to the nitrate concentration in drinking water and changes in the groundwater level. RESULTS: Both the birth rate and the incidence of SIDS decreased during the study period. One quarter of the municipalities constituting 11% of the population had no cases, the maximum incidence being 6.5 per 1000 live births. Seasonality: The northernmost parts of the country had its highest incidence when the rest of the country had its lowest incidence, and the occurrence of individual deaths was associated with the recharge of groundwater which increases its nitrate content. The local incidence of SIDS was correlated (rs = 0.34-0.87) to maximally recorded concentrations of nitrate in drinking water. CONCLUSIONS: The seasonal distribution of SIDS was widely different from the south to the north of the country and seems to be associated with differences in the groundwater level changes subsequent to precipitation, frost penetration, and melting of snow. Use of drinking water with high peak concentrations or great variations in nitrate concentration was correlated to the incidence of SIDS.