The P histo-blood group-related glycosphingolipid sialosyl galactosyl globoside as a preferred binding receptor for uropathogenic Escherichia coli: isolation and structural characterization from human kidney

The P histo-blood group-related glycosphingolipid, sialosyl galactosyl globoside (SGG), has recently been implicated as a preferred binding receptor for uropathogenic Escherichia coli [Stapleton, A. E., Stroud, M. R., Hakomori, S., and Stamm, W. E. (1998) Infect. Immun. 66, 3856-3861]. We report here the purification and complete structural characterization of SGG from normal human kidney. Using metabolically [35S]-labeled E. coli as a probe, a monosialylated glycosphingolipid was isolated to homogeneity. The glycosphingolipid was purified by a combination of high-performance liquid chromatography and preparative high-performance thin-layer chromatography and its structure unambiguously elucidated by 1H NMR, electrospray ionization mass spectrometry, and methylation analysis. Its primary structure was shown to be identical to a previously characterized, developmentally regulated, globo-series glycolipid thought to be unique to human teratocarcinoma. The significance of this structure as a unique receptor in human kidney for uropathogenic E. coli and its role in the pathogenesis of urinary tract infections are discussed.     

Determinants of the growth in the Social Security Administration's disability programs--an overview

This article examines factors affecting the growth in the Social Security Administration's disability programs. We synthesize recent empirical evidence on factors affecting trends in applications and awards for Disability Insurance and Supplemental Security Income (SSI) benefits and duration on the rolls. Econometric analyses of pooled time-series, cross-sectional data for States provide strong evidence of business cycle effects on applications and, to a lesser extent, on awards. Substantial effects of cutbacks in State general assistance programs are also found, especially for SSI. Estimated effects of the aging of the baby boomers, growth in the share of women who are disability insured, the AIDS epidemic, and changes in family structure are also presented. Indirect evidence suggests the importance of programmatic factors, especially for awards, and especially in the mental and musculoskeletal impairment categories. The decline in the average age of new awardees has substantially increased duration, particularly for SSI. As a result, caseload growth would be expected to continue even in the absence of future award growth.     

Clustered p53 immunostaining: a novel pattern associated with prostate cancer progression

Abnormal p53 protein accumulation is typically defined as present when greater than 5 or 10% of cancer cells stain positively. We present a novel approach whereby immunopositivity is defined when 15 or more cells within a 300 x 400-micrometer(2) field exhibit p53 protein accumulation; a feature that we have called "clustered" staining. We assessed p53 immunostaining of moderately differentiated, clinically localized prostate cancers derived from two patient groups: those without cancer recurrence 5 years after radical prostatectomy, and those in whom cancer had recurred following radical prostatectomy. Clustered p53 immunopositivity was present in 10 (63%) of 16 patients in the recurrent group and in only 7 (21%) of 33 in the nonrecurrent group. Clustered p53 staining was clearly associated with cancer recurrence (P < 0.01). This refinement of a commonly used assay may help define the biological aggressiveness of a cancer.     

Determination of thresholds for detection of cerebellar blood flow deficits in brain SPECT images

Two observer studies were performed to determine the threshold (i.e., ratio of the counts in a lesion area to the counts in the corresponding contralateral region) at which two experienced observers diagnosed blood flow deficits in the cerebellum in 99mTc-HMPAO SPECT scans to be clinically significant, and investigate the effect of the intensity mapping scale on the detectability of lesions. METHODS: Lesions representing blood flow deficits varying from no decrease to a 12.5% decrease were simulated in 300 patient images. The first study, a receiver-operator characteristics (ROC) experiment, used two observers to compare the detectability of lesions with three intensity mapping scales: two pseudocolor scales, and a linear gray scale. A second "threshold-criterion" study was done to estimate the threshold at which observers determine deficits to be clinically significant. RESULTS: In the ROC study, the observers were more accurate in detecting lesions displayed in pseudocolor than in gray scale. In the threshold-criterion study, the threshold at which observers assessed clinically significant deficits was found to range between 0.900 and 0.950 (corresponding to a 5%-10% decrease in counts), depending on the observer, and the intensity mapping scale. For both observers, the detection threshold was higher (i.e., closer to 1.0) with the pseudocolor scale than with the gray scale. CONCLUSION: The definition of a threshold value for use in quantitative techniques is dependent on both the observer and the intensity mapping scale. Observers were more accurate with the pseudocolor scales.     

Book Review

During the various steps of the azo dye bleach process (ADBP) certain electrochemical conditions must be adjusted, otherwise the redox processes involved will not run. The maintaining of these conditions during the various steps of the process and the requirements for the individual reactants are discussed in general terms.     

A general method for drawing area-proportional Euler diagrams

Area-proportional Euler diagrams have many applications, for example they are often used for visualizing data in medical and biological domains. There have been a number of recent research efforts to automatically draw Euler diagrams when the areas of the regions are not considered, leading to a range of different drawing techniques. By contrast, substantially less progress has been made on the problem of automatically drawing area-proportional Euler diagrams, although some partial results have been derived. In this paper, we considerably advance the state-of-the-art in area-proportional Euler diagram drawing by presenting the first method that is capable of generating such a diagram given any area-proportional specification. Moreover, our drawing method is sufficiently flexible that it allows one to specify which of the typically enforced well-formedness conditions should be possessed by the to-be-drawn Euler diagram.