We identified home characteristics associated with the level of airborne endotoxin in 111 Boston-area homes enrolled in a cohort study of home exposures and childhood asthma, and we developed a predictive model to estimate airborne endotoxin. We measured endotoxin in family-room air and in dust from the baby's bed, family room, bedroom, and kitchen floor. Level of airborne endotoxin was weakly correlated (r < 0.3) with level of endotoxin in each of the four types of dust samples and was significantly correlated with endotoxin in family-room dust (p < 0.05). Endotoxin in family-room dust accounted for < 6% of the variability of airborne endotoxin. In a multivariate model, certain home characteristics were positively (p < 0.05) associated with airborne endotoxin. These included current presence of dog (difference in level, dog vs. no dog = 72%, partial R(2 )= 12.8%), past presence of dog (partial R(2) = 5.5%), and endotoxin level in family-room dust (partial R(2) = 5.3%). Use of a dehumidifier (partial R(2) = 6.4%) was negatively associated (p = 0.02; difference = -31%) with airborne endotoxin. Other home characteristics were identified as important determinants of increased airborne endotoxin in this model, but individual coefficients were not statistically significant (alpha = 0.05): total amount of fine dust collected in the home (partial R(2 )= 3.8%), concrete floor in family room (3.7%), water damage (3.6%), and use of cool-mist humidifier in past year (2.7%). This multivariate model explained 42% of the variability of airborne endotoxin levels, a substantial improvement over that with dust endotoxin alone. Airborne endotoxin in Boston-area homes appears to be determined by the presence of dogs, moisture sources, and increased amounts of settled dust.

Diabetic ulceration is one of the most debilitating complications of diabetes and is the main cause of amputation. The diabetic environment is characterized by prolonged inflammation and abnormal angiogenesis, leading to delayed wound healing. Thus, regulation of inflammation and neovascularization is considered a desirable target for diabetes. The critical purpose of this study was to determine whether systemically administered Substance P (SP) could promote wound healing in diabetic environments via suppression of inflammation, induction of angiogenesis, and mobilization of stem cells. The effect of SP was assessed by analyzing epidermal and dermal recovery, vessel formation, cytokine secretion profile, and the stem cell pool in the circulation and bone marrow. Compared with the vehicle-treated group, the SP-treated group exhibited more rapid wound coverage, reduced infiltration of leukocytes, suppression of injury-mediated enlargement of the spleen and mesenteric lymph nodes, reduced tumor necrosis factor-alpha levels, increased interleukin-10, elevated pool of M2 monocytes and vascular endothelial growth factor levels in the blood. Moreover, the stem cell pool in the bone marrow, which is very low in diabetes, was markedly restored by SP to normal levels, which could provide a favorable environment to facilitate wound healing in diabetes. This result demonstrates, for the first time, a possible application of SP for the treatment of diabetic complications, including diabetic ulcers.

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