We developed an omnidirectional Compton camera for radioactive environmental monitoring which can visualize gamma rays with energy below 250 keV emitted from various radiopharmaceuticals used in ...nuclear medicine facilities to prevent occupational radiation exposure. An omnidirectional Compton camera based on high light yield scintillators CsI(Tl) or NaI(Tl) developed in our previous studies is a promising system for environmental radiation monitoring because it has a wide field of view and high sensitivity for sub-MeV gamma rays. However, its sensitivity rapidly decreases below 250 keV because photoelectric effect becomes more dominant than the Compton scattering process due to their large effective atomic numbers (approximately 50). Thus, CaF2(Eu) was adopted, which has both low effective atomic number (approximately 15) and high light yield. Four CaF2(Eu) crystals were arranged symmetrically to achieve a relatively uniform acceptance in all directions. Similarly, the detector rotation technique was adopted to suppress artificial patterns in a reconstructed gamma-ray image because of the small number of crystals. Through experiments in a laboratory and at a nuclear medicine facility, the capability of the camera to visualize gamma rays in energies from 250 keV to 60 keV with reasonable observation time for practical clinical use was confirmed.
A reduction in ankle-brachial BP index (ABPI) is associated with generalized atherosclerotic diseases and predicts cardiovascular mortality and morbidity in several patient populations. However, a ...large-scale analysis of ABPI is lacking for hemodialysis (HD) patients, and its use in this population is not fully validated. A cohort of 1010 Japanese patients undergoing chronic hemodialysis was studied between November 1999 and May 2002. Mean age at entry was 60.6 +/- 12.5 yr, and duration of follow-up was 22.3 +/- 5.6 mo. Patients were stratified into five groups (< 0.9, > or = 0.9 to < 1.0, > or = 1.0 to < 1.1, > or = 1.1 to < 1.3, and > or = 1.3) by ABPI measured at entry by an oscillometric method. The frequency distribution of ABPI was 16.5% of patients < 0.9, 8.6% of patients > or = 0.9 to < 1.0, 16.9% of patients 1.0 > or = to < 1.1, and 47.0% of patients > or 1.1 to < 1.3, whereas 10.9% of patients had an abnormally high ABPI (> or = 1.3). The relative risk of a history of diabetes mellitus (DM), cardiovascular, and cerebrovascular disease was significantly higher in patients with lower ABPI than those with ABPI > or = 1.1 to <1.3. During the study period, 77 cardiovascular and 41 noncardiovascular fatal events occurred. On the basis of Cox proportional hazards regression analysis, ABPI emerged as a strong independent predictor of all-cause and cardiovascular mortality. After adjustment for confounding variables, the hazard ratio (HR) for ABPI < 0.9 was 4.04 (95% confidence interval, 2.38 to 6.95) for all-cause mortality and 5.90 (2.83 to 12.29) for cardiovascular mortality. Even those with modest reductions in the ABPI (> or = 0.9 to <1.1) appeared to be at increased risk. Patients having abnormally high ABPI (> or = 1.3) also had poor prognosis (HR, 2.33 1.11 to 4.89 and 3.04 1.14 to 8.12 for all-cause and cardiovascular mortality, respectively). Thus, the present findings validate ABPI as a powerful and independent predictor for all-cause and cardiovascular mortality among hemodialysis patients.
IgA nephropathy (IgAN) is a common type of primary glomerulonephritis that constitutes a major cause of end-stage renal disease. Oral and/or intravenous glucocorticoid therapy can protect against ...progression of IgAN in patients with preserved renal function. We evaluated steroid therapy in IgAN with established renal dysfunction.
We retrospectively analyzed the effect of methylprednisolone (MP) pulse therapy in 8 IgAN patients with serum creatinine concentrations (sCr) 2.76 +/- 1.32 mg/dl (mean +/- SD). In each patient renal function had progressively deteriorated in the 12 months preceding treatment, as indicated by negative slopes of 1/sCr plotted against time (regression coefficients).
Regression coefficients during the 12 months following therapy improved significantly from -0.02333 +/- 0.00732 to -0.00036 +/- 0.00423 dl/mg/month, respectively. The mean difference in slope was 0.0230 +/- 0.0076 dl/mg/month (95% confidence interval, 0.0165 to 0.0295, p < 0.001). Proteinuria also significantly decreased from a mean urine protein/creatinine ratio of 2.57 +/- 1.12 before therapy to 1.12 +/- 0.84 6 months after therapy (p < 0.005). Other factors that might affect progression of renal dysfunction remained unchanged during the observation periods.
Corticosteroids may attenuate progression of renal failure and delay the need for dialysis in this patient population, although a large randomized trial is necessary.
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