Improvements in the method of radiation anomaly detection by spectral comparison ratios.

We present a new procedure for configuring the Nuisance-rejection Spectral Comparison Ratio Anomaly Detection (N-SCRAD) method. The procedure minimizes detectable count rates of source spectra at a specified false positive rate using simulated annealing. We also present a new method for correcting the estimates of background variability used in N-SCRAD to current conditions of the total count rate. The correction lowers detection thresholds for a specified false positive rate, enabling greater sensitivity to targets.

Elastic alpha-12C scattering and the 12C(alpha,gamma)16O E2 S factor.

Angular distributions of 12C(alpha,alpha)12C have been measured for E(alpha) = 2.6-8.2 MeV, at angles from 24 to 166, yielding 12 864 data points. R-matrix analysis of the ratios of elastic scattering yields a reduced width amplitude of gamma12 = 0.47 +/- 0.06 MeV(1/2) for the Ex = 6.917 MeV (2+) state in 16O(a = 5.5 fm). The dependence of the chi2 surface on the interaction radius a has been investigated and a deep minimum is found at a = 5.42(+0.16)(-0.27) fm. Using this value of gamma12, radiative alpha capture and 16N beta-delayed alpha-decay data, the S factor is calculated at E(c.m.) = 300 keV to be S(E2)(300) = 53(+13)(-18) keV b for destructive interference between the subthreshold resonance tail and the ground state E2 direct capture.

Cytomegalovirus-induced necrotizing and crescentic glomerulonephritis in a renal transplant patient.

A 35-year-old black man with end-stage renal disease from biopsy-proven focal segmental glomerulosclerosis developed worsening function of his renal allograft 160 days after living related donor renal transplantation. Renal biopsy showed necrotizing and crescentic glomerulonephritis (NCGN) and presence of intraglomerular viral inclusions confirmed by immunocytochemical stain and in situ hybridization techniques to be cytomegaloviral in origin. Electron microscopy showed no immune complexes, and workup for other causes of NCGN was negative. The patient was treated with ganciclovir without other changes in his immunosuppressive regimen. After 8 weeks of ganciclovir therapy, a second renal transplant biopsy showed resolution of the glomerular process and disappearance of the cytomegalovirus (CMV) inclusions. The resolution of the glomerular process with treatment for CMV infection, and without other change in therapy, strongly supports a causative link between CMV and NCGN in this patient. This case represents the first report of CMV-associated NCGN in a renal transplant patient.

Clinical response to prolonged corticosteroids in a patient with human immunodeficiency virus-associated nephropathy.

Human immunodeficiency virus-associated nephropathy (HIVAN) is characterized by massive proteinuria with rapidly progressive renal failure. We report an adult with HIV infection who developed nephrotic-range proteinuria and acute renal failure requiring hemodialysis. Renal biopsy findings were consistent with HIVAN, exhibiting focal and segmental glomerulosclerosis with dilated microcystic tubules filled with pale eosinophilic material. Institution of corticosteroid therapy was followed by significant improvement in renal function and proteinuria. Corticosteroids were tapered, and the patient experienced worsening of his renal failure and proteinuria. A second course of corticosteroids was again associated with improved renal function. This and other reports suggest that corticosteroids may improve the clinical course of HIVAN.

Collapsing glomerulopathy: a clinically and pathologically distinct variant of focal segmental glomerulosclerosis.

Sixteen patients with renal biopsy findings of extensive focal glomerular capillary collapse, visceral epithelial cell hypertrophy and hyperplasia, and variable degrees of tubulointerstitial injury in the absence of evidence for human immunodeficiency virus (HIV) infection or intravenous drug abuse were prospectively identified by renal biopsy. The pathologic process was designated collapsing glomerulopathy to distinguish it from other patterns of focal glomerular sclerosis. The clinical and pathologic characteristics of these 16 patients were analyzed and compared to a group of 25 patients with noncollapsing focal segmental glomerulosclerosis (FSGS). Thirteen of 16 patients with collapsing glomerulopathy were black as compared with 11 of 25 with FSGS (P = 0.018). The most common findings at presentation were hypertension and manifestations of the nephrotic syndrome. Although the duration of symptoms prior to presentation was no longer in the collapsing glomerulopathy group, the presenting mean serum creatinine was higher in patients with collapsing glomerulopathy than in those with noncollapsing FSGS (3.5 +/- 3.4 mg/dl vs. 1.3 0.6 mg/dl, P = 0.001). Twenty-four-hour urine protein excretion was also higher in the collapsing glomerulopathy group (13.2 +/- 7.7 g/day vs. 4.6 +/- 4.5 g/day FSGS, P = 0.005). The collapsing glomerulopathy patients had a mean age of 41.4 +/- 19.1 (range 19 to 81), a male-to-female ratio of 11:5 and a black-to-white ratio of 13:3. Renal survival, evaluated by life-table analysis, was markedly worse in collapsing glomerulopathy patients than in FSGS patients (P = 0.0004). It is proposed that collapsing glomerulopathy is a distinct entity characterized by black racial predominance, massive proteinuria, relatively rapidly progressive renal insufficiency, and distinctive pathologic findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Tropical forests and the global carbon cycle.

New data on the three major determinants of the carbon release from tropical forest clearing are used in a computer model that simulates land use change and its effects on the carbon content of vegetation and soil in order to calculate the net flux of carbon dioxide between tropical ecosystems and the atmosphere. The model also permits testing the sensitivity of the calculated flux to uncertainties in these data. The tropics were a net source of at least 0.4 x 10(15) grams but not more than 1.6 x 10(15) grams of carbon in 1980, considerably less than previous estimates. Decreases in soil organic matter were responsible for 0.1 x 10(15) to 0.3 x 10(15) grams of the release, while the burning and decay of cleared vegetation accounted for 0.3 x 10(15) to 1.3 x 10(15) grams. These estimates are lower than many previous ones because lower biomass estimates and slightly lower land clearing rates were used and because ecosystem recovery processes were included. These new estimates of the biotic release allow for the possibility of a balanced global budget given the large remaining uncertainties in the marine, terrestrial, and fossil fuel components of the carbon cycle.

Ultrasonography and oral cholecystography: a comparison of their use in the diagnosis of gallbladder disease.

The charts of all cholecystectomy patients at the White Memorial Medical Center, Los Angeles, from January 1977 to December 1979 were reviewed; of 374 patients, 76 had had both abdominal ultrasound scan and oral cholecystography performed preoperatively. Cholecystography accurately diagnosed gallbladder disease in 71 of these 76 patients, an accuracy rate of 93.4% with one false-positive and four false-negative results. Ultrasonography correctly predicted gallbladder disease in 66 of 76 patients, an accuracy rate of 86.8%, with one false-positive and nine false-negative results. On the basis of this study and others in the literature, ultrasound scanning is recommended as the initial screening diagnostic study for gallbladder disease. Oral cholecystography should follow in patients in whom ultrasonography fails to identify gallbladder calculi.