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To evaluate exposure to ionizing radiation during Amplatzer device occlusion, a prospective study was performed to measure surface entrance radiation dose by thermoluminescent dosimetry (TLD). Between June 1998 and April 1999, dosimetry was carried out on 12 patients with Amplatzer device occlusion of atrial septal defects (n = 10) or Fontan fenestration (n =) and 12 age-matched patients who underwent diagnostic catherization. TLD chips were placed at the posterior (PA) and right lateral (LA) chest wall as well as the thyroid (TH) and gonadal (GN) regions. The Amplatzer group had a median age of 6.4 yr (2.4-12.4 yr) and a median weight of 23.7 kg (15.6-28.9 kg), which were similar (p = NS) to those of the control group, who had a median age of 7.9 yr (3.3-16.2 yr) and a median weight of 29.9 kg (10.6-58.0 kg). Device placement was successful in 11 of 12 patients; one device was removed owing to partial obstruction of the right-upper pulmonary vein. Fluoroscopy times were also similar in the Amplatzer group (23.5 +/- 2.1 min) and the control group (16.4 +/- 3.1 min; P = NS). The measured surface entrance doses of the Amplatzer group was similar (p = NS) to those of the control group in all four regions: PA (4.96 +/- 1.88 vs. 6.07 +/- 2.16 cGy), LA (5.22 +/- 1.68 vs. 3.13 +/- 1.25 cGy), TH (0.92 +/- 0.14 vs. 0.69 +/- 0.09 cGy), and GN (0.20 +/- 0.00 vs. 0.22 +/- 0.01cGy). Fluoroscopy times and measured surface entrance doses of ionizing radiation in patients undergoing Amplatzer device occlusion are similar to those in patients undergoing routine diagnostic catheterization.

The effects of cesium promoters on silver catalysts, supported by γ-alumina, were studied by adsorbing mono- or dilabeled [13C]ethylene onto the catalysts and performing low-temperature (70 K) solid-state13C NMR measurements on the ethylene. Selective isotopic enrichment was used to investigate the electronic environment present in and around the ethylene molecule as a function of promoter concentration. Changes in the spectroscopic parameters describing the ethylene lineshapes were extracted using a nonlinear least-squares procedure. These parameters were then used to determine the structure of the ethylene molecule on the surface and to probe the changes induced by adding cesium promoters. Similarly, the state of cesium in the catalyst system was investigated by spin-echo double-resonance spectroscopy and scanning electron microscopy X-ray fluorescence methods. The results imply that the form of cesium is not that of an oxide but, in all probability, reflect those of a cation–anion pair.

A suite of nuclear magnetic resonance (NMR) line shape programs, that simulate five common interactions in solids, has been written. Non-linear least squares routines based on the SIMPLEX and Levenberg-Marquardt algorithms have been implemented to extract physical parameters from solid state NMR powder line shapes. Both optimization strategies produce error estimates for the parameters extracted. As an example to illustrate the difficulties of applying least squares in NMR, the system of mono- and dilabeled 13C ethylene on silver, supported on γ-alumina was studied. The experimental line shapes produced were analyzed by non-linear least squares fitting to extract the principal components of the chemical shift (CS) tensor, the bond distance, and the orientation of the components of the chemical shift tensor in the molecular frame of ethylene. To evaluate the techniques performance, the reliability of the error estimates produced by the optimization has been investigated.

We examined the effects of a new antiangiogenic isocoumarin, NM-3, as a radiation modifier in vitro and in vivo. The present studies demonstrate that NM-3 is cytotoxic to human umbilical vein endothelial cells (HUVECs) but not to Lewis lung carcinoma (LLC) cells nor Seg-1, esophageal adenocarcinoma cells, in clonogenic survival assays. When HUVEC cultures are treated with NM-3 combined with ionizing radiation (IR), additive cytotoxicity is observed. In addition, the combination of NM-3 and IR inhibits HUVEC migration to a greater extent than either treatment alone. The effects of treatment with NM-3 and IR were also evaluated in tumor model systems. C57BL/6 female mice bearing LLC tumors were given injections for 4 consecutive days with NM-3 (25 mg/kg/day) and treated with IR (20 Gy) for 2 consecutive days. Combined treatment with NM-3 and IR significantly reduced mean tumor volume compared with either treatment alone. An increase in local tumor control was also observed in LLC tumors in mice receiving NM-3/IR therapy. When athymic nude mice bearing Seg-1 tumor xenografts were treated with NM-3 (100 mg/kg/day for 4 days) and 20 Gy (four 5 Gy fractions), significant tumor regression was observed after combined treatment (NM-3 and IR) compared with IR alone. Importantly, no increase in systemic or local tissue toxicity was observed after combined treatment (NM-3 and IR) when compared with IR alone. The bioavailability and nontoxic profile of NM-3 suggests that the efficacy of this agent should be tested in clinical radiotherapy.

The early and 1-year follow-up of a single United States center using the Amplatzer atrial septal defect closure device is reported. Complete closure was documented in all patients by 1 year after device implantation.

Factor analysis has been used to deduce the composition of multicomponent magic angle spinning NMR spectra comprised of overlapping isotropic peaks. The technique has been used to determine the number of constituents present and was combined with a target transformation minimization procedure to identify the component MAS spectra. The new analysis procedure is compared to the conventional least-squares approach and is found to be superior in all cases.

The work of Goldblatt,1Page2and others has shown that hypertension may be produced experimentally in dogs and monkeys by effecting a relative ischemia of one or both kidneys. There are many ways in which clinical pathology might simulate the experimental methods of these workers. Blatt and Page3have studied a case of lymphosarcoma with hypertension apparently due to constriction of both renal arteries by the tumor mass. Ratliff,4Crabtree5and McIntyre6have reported hypertension in patients with unilateral, chronically infected kidney lesions. Of this group Goldblatt has said,7"It becomes probable that the hypertension associated with unilateral or bilateral pyelonephritis in children and adults occurs only in those cases in which there is associated vascular sclerosis or in which the inflammatory disease produces the same effect on renal circulation as does vascular disease." The reported cases of this type which have come to