A Home-Based Diaphragmatic Breathing Retraining in Rural Patients With Heart Failure.

Dyspnea limits physical activity and functional status in heart failure patients. This feasibility study examined effects of a diaphragmatic breathing retraining (DBR) intervention delivered over 8 weeks with follow-up at 5 months. The intervention group (n = 18) was trained at baseline and received four telephone calls. An attention control group (n = 18) received four telephone calls with general health information. Results from linear mixed model analysis with effect sizes (η(2)) showed dyspnea improved in both groups, with little difference between groups. Compared with attention alone, the intervention increased physical activity (calories expended; η(2) = .015) and functional status (η(2) = .013) across the 5-month follow-up and increased activity counts at 8 weeks (η(2) = .070). This intervention was feasible and demonstrated promising effects on activity and function but not by reducing dyspnea. Patients may have increased physical activity because of instructions to use DBR during activities of daily living. Further exploration of the intervention's underlying physiological effect is needed.

O6-3-[131I]iodobenzylguanine: improved synthesis and further evaluation of a potential agent for imaging of alkylguanine-DNA alkyltransferase.

O(6)-Benzylguanine derivatives with suitable radionuclides attached to the benzyl ring are potentially useful in the noninvasive imaging of the DNA repair protein, alkylguanine-DNA alkyltransferase (AGT). Previously, O(6)-3-[(131)I]iodobenzylguanine ([(131)I]IBG) was prepared using a two-step approach; we now report its synthesis in a single step by the radioiododestannylation of O(6)-3-(trimethylstannyl)benzylguanine in 85-95% radiochemical yield. The in vitro specific uptake of [(131)I]IBG in DAOY human medulloblastoma cells, in TE-671 human rhabdomyosarcoma cells and a CHO cell line transfected to express AGT was linear (r(2) = 0.9-1.0) as a function of cell density. After intravenous injection of [(131)I]IBG in athymic mice bearing TE-671 xenografts, tumor uptake was 1.38 +/- 0.34% ID/g at 0.5 h and declined at 2 and 4 h. Preadministration of O(6)-(3-iodobenzyl)guanine (IBG) at 0.5 h increased uptake not only in tumor but also in several normal tissues. Notable exceptions were thyroid (p < 0.05), lung (p <0.05) and stomach. After intratumoral injection of [(131)I]IBG in the same xenograft model, the uptake in tumors that were depleted of AGT by BG treatment (165.8 +/- 27.5% ID/g) was about 60% of that in control mice (272.4 +/- 48.2% ID/g; p < 0.05).