ABSTRACT
Polarization transfer efficiency in liquid-state dynamic nuclear polarization (DNP) depends on the interaction between polarizing agents (PAs) and target nuclei modulated by molecular motions. We show how translational and rotational diffusion differently affect the DNP efficiency. These contributions were disentangled by measuring 1H-DNP enhancements of toluene and chloroform doped with nitroxide derivatives at 0.34 T as a function of either the temperature or the size of the PA. The results were employed to analyze 13C-DNP data at higher fields, where the polarization transfer is also driven by the Fermi contact interaction. In this case, bulky nitroxide PAs perform better than the small TEMPONE radical due to structural fluctuations of the ring conformation. These findings will help in designing PAs with features specifically optimized for liquid-state DNP at various magnetic fields.
ABSTRACT
There has been substantial improvement in survival in patients with Wilms' tumor over the last 30 years in the United States. This has been the direct result of the efforts of the National Wilms' Tumor Study Group. This group was established in 1969 through the conglomeration of pediatric divisions of two existing cooperative study groups for the purpose of accruing large enough patient populations to conduct meaningful clinical trials. Thus far, four National Wilms' tumor trials have been completed. The fifth study is currently accepting patients for treatment. This article reviews the remarkable success in the treatment of Wilms' tumor and the evolution of present day postoperative therapy.
Subject(s)
Kidney Neoplasms/therapy , Wilms Tumor/therapy , Child , Combined Modality Therapy , Humans , Kidney Neoplasms/drug therapy , Kidney Neoplasms/mortality , Kidney Neoplasms/surgery , Survival Rate , Wilms Tumor/drug therapy , Wilms Tumor/mortality , Wilms Tumor/surgeryABSTRACT
This study details the case reports of two children who developed slipped capital femoral epiphyses (SCFE) after receiving external irradiation. The clinical and diagnostic features of postradiation SCFE are reviewed and discussed. Guidelines for the management of children who receive pelvic irradiation are presented.
Subject(s)
Epiphyses, Slipped/etiology , Pelvic Neoplasms/radiotherapy , Radiation Injuries , Child , Child, Preschool , Female , Femur , Humans , MaleABSTRACT
Endodermal sinus tumor of the vagina, a rare pediatric malignancy, was managed with primary chemotherapy (vincristine, dactinomycin, cyclophosphamide [VAC]) followed by local excision without radical surgery or pelvic irradiation. Treatment-related complications were acceptable, and there is no evidence of disease 30 months after discontinuing all therapy (50 months after diagnosis). As a treatment option, primary chemotherapy is viewed as a highly attractive alternative modality, preserving potential reproductive and sexual function in long-term survivors, and appears to be the treatment of choice.
