Soluble urokinase receptor is a biomarker of cardiovascular disease in chronic kidney disease.

Soluble urokinase-type plasminogen activator receptor (suPAR) accumulates in patients with chronic kidney disease (CKD). In various non-CKD populations, suPAR has been proposed as a prognostic marker for mortality and cardiovascular disease. However, it is not known whether suPAR holds prognostic information in patients with mild-to-moderate CKD. In a prospective observational study of 476 patients with mild-to-moderate kidney disease, we examined multivariate associations between suPAR, overall mortality, and cardiovascular events. After a mean follow-up of 57 months, 52 patients died and 76 patients had at least one fatal or nonfatal cardiovascular event. Higher suPAR was directly and significantly associated with both overall mortality (univariate hazard ratio 5.35) and cardiovascular events (univariate hazard ratio 5.06). In multivariate analysis, suPAR remained significantly associated with cardiovascular events (full model, hazard ratio 3.05). Thus, in patients with mild-to-moderate CKD, suPAR concentrations show a clear, direct, and graded association with a higher risk for new-onset cardiovascular disease.

The soluble urokinase receptor is not a clinical marker for focal segmental glomerulosclerosis.

The soluble urokinase receptor (suPAR) promotes proteinuria and induces focal segmental glomerulosclerosis (FSGS)-like lesions in mice. A serum suPAR concentration cutoff of 3000 pg/ml has been proposed as a clinical biomarker for patients with FSGS. Interestingly, several studies in patients with glomerulopathy found an inverse correlation between the estimated glomerular filtration rate (eGFR) and suPAR. As patients with FSGS present at different eGFRs, we studied the relationship between eGFR and suPAR in a cohort of 476 non-FSGS patients and 54 patients with biopsy-proven idiopathic FSGS. In the non-FSGS patients, eGFR was the strongest significant determinant of suPAR. The proposed cutoff for suPAR in FSGS patients was exceeded in 17%, 39%, and 88% in patients with eGFRs of more than 60, 45-60, and 30-45 ml/min per 1.73 m(2), respectively. In patients with eGFR of <30 ml/min per 1.73 m(2), suPAR exceeded the cutoff in 95% of patients. Levels of suPAR in patients with idiopathic FSGS overlapped with non-FSGS controls and for any given eGFR did not discriminate FSGS cases from non-FSGS controls. In the overall cohort, there was a negative association between idiopathic FSGS and suPAR, and idiopathic FSGS was not an independent predictor of FSGS concentration over 3000 pg/ml. Thus, this study does not support an absolute, eGFR-independent, suPAR concentration cutoff as a biomarker for underlying FSGS pathology and questions the validity of relative, eGFR-dependent suPAR cutoff values.

Can we improve the positive predictive value of atypical glandular cells not otherwise specified?

The category of atypical glandular cells (AGC) in gynecologic cytopathology presents many well-documented diagnostic challenges, the most significant related to high interobserver variability, low specificity, and low positive predictive value. The current Bethesda System provides criteria for specific glandular categories including atypical endocervical cells not otherwise specified (AEC-NOS), AEC favor neoplastic, and atypical endometrial cells. The Bethesda System does, however, acknowledge that in some cases AGC cannot be categorized based upon cell of origin, in which case the generic term "atypical glandular cells" (AGC) may be used. We sought to determine whether further refinement of the current Bethesda System criteria for AEC-NOS might increase the positive predictive value of the general category of AGC. Fifty-three cases of AGC with documented histologic follow-up at the University of Illinois Hospital were reviewed. The cases were graded on each of the eight specific cytologic criteria recommended by the current Bethesda System for AEC-NOS using a study-developed three-tier grading system. Multiple regression analysis showed that four of the cytologic criteria in combination--nuclear enlargement, nuclear pleomorphism, increased nuclear-to-cytoplasmic (N/C) ratio, and cells occurring in sheets and strips with cell crowding and nuclear overlap--discriminated positive histologic outcome slightly better than any single criterion alone. In addition, simple logistic regression analysis showed nuclear enlargement to have a marginal independent association with positive histologic outcome (P = 0.0566). No other criterion was independently associated with outcome. Ancillary methods seem indicated to increase the positive predictive value of AGC at this time.

Real-time PCR as a new in vitro biocompatibility method to measure leukocyte response to surface contact in dialysis filter devices.

INTRODUCTION: The mortality risk of dialysis patients is still elevated. Even though there is continuous improvement in the biocompatibility of dialysis devices and treatments, there is clinical evidence of a negative inflammatory impact. One dialysis-related risk factor to be considered in this regard may be the repeated blood exposure to foreign filter surfaces. Standard test methods do not allow differences to be shown between most of the common dialysis devices. METHODS: A new highly sensitive in vitro test system was developed by analyzing the response of leukocytes to surface contact in dialysis filter devices by means of quantitative real time PCR and flow cytometry. Membrane surface studies provided additional physical data. RESULTS: An increase in the transcription level of specific pro-inflammatory genes, particularly IL-1b, TNF alpha, and IL-8, was observed after blood contact to the filter devices. In two sets of pairwise filter comparisons, radiation-sterilized filters showed stronger cell activation, more hydrophilic membranes, and rougher surfaces. CONCLUSIONS: Quantitative real time RT-PCR was shown to be a new in vitro test method with increased sensitivity for detecting differences in activation levels of leukocytes upon membrane contact. Correlating leukocyte activation levels with surface properties opens new opportunities for understanding leukocyte activation upon membrane contact and thus guides further improvements in the biocompatibility of dialysis filter devices.

The role of polymer surface degradation and barium sulphate release in the pathogenesis of catheter-related infection.

BACKGROUND: Susceptibility to infection and thrombosis of intravascular catheters is increased by surface irregularities, which might be prevented by coating. METHODS: BaSO4 release from conventional haemodialysis catheters (CC) and modified catheters (MC) which had been coated with a surface-modifying additive (SMA) was assessed in vivo and in vitro. For the in vivo part, patients were randomized to receive a temporary CC or MC, with crossover after 1 week. After retrieval, catheters were examined using scanning electron microscopy to assess surface integrity, and an in vitro model of catheter exposure to the bloodstream was used to evaluate surface morphology and susceptibility to bacterial adhesion and proliferation. RESULTS: BaSO(4) moieties covered 14.7 +/- 3.7% of the surface of unused CC. After in vivo use in 16 patients, 62.7 +/- 32.9 x 10(3) holes/mm(2) were detected, indicating BaSO(4) detachment from 3.3 +/- 1.7% of the catheter surface. No defects were observed in unused CC and in MC, whether used or unused. After incubation of four catheters (two of each type) with Staphylococcus epidermidis, the two degraded CC showed an immediate and strong bacterial growth as indicated by an increase in medium impedance of 0.512%/10 min compared to -0.021%/10 min in MC (P < 0.001). CONCLUSIONS: Short-term exposure of CC to the bloodstream causes BaSO(4) particle release, resulting in surface irregularities predisposing to bacterial proliferation. BaSO(4) release can be prevented by SMA coating.

The role of deeper levels and ancillary studies (p16(Ink4a) and ProExC) in reducing the discordance rate of Papanicolaou findings of high-grade squamous intraepithelial lesion and follow-up cervical biopsies.

BACKGROUND: Discordant results of cervical biopsy histology after a cytologic diagnosis of high-grade squamous intraepithelial lesion (HSIL) are often attributed to sampling variation. The purpose of the current study was to determine whether deeper levels and ancillary staining (p16(Ink4a) and ProExC) reduce the discordant rate. METHODS: A total of 246 cases of HSIL were retrieved from the computerized database from 2005 and 2006. Of these cases, 151 were followed by cervical biopsy. There was cytologic-histologic correlation in 87 cases, as defined by the presence of high-grade (2 or 3) cervical intraepithelial neoplasia (HGCIN). For each discordant biopsy (n = 64), 2 deeper levels for hematoxylin and eosin (H&E) were taken at 30-micro and 90-micro depths, and 4 sections for p16(Ink4a) and ProExC staining were taken at a 60-micro depth. All cytologic and histologic material from these 64 cases was reviewed by 3 cytopathologists. In 2 cases, the original HSIL diagnoses were downgraded and the cases censored from the study. RESULTS: Fifty-seven of the 62 discordant cases had sufficient tissue for deeper levels and ancillary staining. Two of 57 cases were reclassified to HGCIN. In both of these cases, reclassification was suggested by results of immunostains; however, the H&E sections were necessary for definitive interpretation of the immunostain results. CONCLUSIONS: In the current study, deeper levels and ancillary staining with p16(Ink4a) and ProExC did not significantly reduce the discordance rate. Although there are many known causes of sampling variation, including factors related to colposcopic technique, regression of infection, and insufficient histologic sectioning, sampling variation remains a valid justification of noncorrelation in women with HSIL followed up by cervical biopsy alone.

Validity of sampling error as a cause of noncorrelation.

BACKGROUND: Sampling error is a common explanation of noncorrelation in women whose Papanicolaou (Pap) tests show high-grade intraepithelial lesions (HSIL) but whose follow-up cervical biopsies show only cervical intraepithelial neoplasia (CIN) 1, koilocytosis, or reactive/inflammatory changes. The purpose of this study was to demonstrate the validity of sampling error in this setting by determining the proportion of negative colposcopic cervical biopsies in women with HSIL who subsequently undergo cone/loop electrode excision procedure (LEEP) biopsies or repeat cervical biopsies that confirm the diagnosis of high-grade CIN (HGCIN). METHODS: In all, 368 cases of HSIL were retrieved from the computerized database from January 1, 2003 to December 31, 2005. Follow-up was obtained as part of routine quality assurance/quality control activities including cytologic-histologic correlation. RESULTS: A total of 368 HSIL Pap diagnoses were retrieved. Of the 254 cases that were followed up by cervical biopsy, 146 showed HGCIN in the biopsy. Of the remaining 108 patients whose cervical biopsies failed to demonstrate HGCIN, 47 had a subsequent procedure, either cone/LEEP, cervical biopsy, or repeat Pap test. Cone biopsy/LEEP was performed in 34 cases (72.3%) with a diagnosis of HGCIN in 19. Repeat cervical biopsy was performed in 9 cases (19.1%) with HGCIN diagnosed in 5. Repeat Pap test was performed in 4 cases (8.5%) with HSIL diagnosed in 2. CONCLUSIONS: In the population of women with HSIL by Pap test followed up by cervical biopsy with or without subsequent cone/LEEP, there was a discordant cervical biopsy rate for HGCIN of 43%. In the subgroup of women with HSIL by Pap test followed up by cervical biopsy and subsequent cone/LEEP or repeat cervical biopsy, the proportion of women with negative colposcopic cervical biopsy and subsequent histology-proven HGCIN was 56%. These figures justify sampling error as a valid cause of noncorrelation in women with HSIL followed up by cervical biopsy alone.

Prolonged catheter survival in intermittent hemodialysis using a less thrombogenic micropatterned polymer modification.

Adequate vascular access is a major prerequisite for hemodialysis treatment. Catheter related complications, in particular thrombus formation, are frequent, difficult to handle, and cost intensive. We investigated whether a new surface modified catheter containing a microdomain structure is beneficial for catheter survival. Surface thrombogenicity of standard double lumen catheters (STD-DC) and surface modified film-coated domain structured double lumen catheters (FCDS-DC) consisting of a novel reactive polyurethane copolymer coating was assessed by measurement of thrombinantithrombin (TAT) III complex in vitro. Furthermore, in a randomized observational study with 20 patients on hemodialysis, we analyzed catheter survival of either STD-DC (GamCath GDK 11 French, length 12.5 or 15 cm) or FCDS-DC (GamCath Dolphin GDK 11 French, length 12.5 or 15 cm). Catheter care protocol was identical, and dialysis treatment parameters were kept constant in both groups. In vitro measured surface thrombogenicity was reduced in the modified catheter compared with standard catheter. The clinical investigation revealed that both number of days before catheter removal according to clinical requirements and number of treatments per catheter were significantly higher with the modified catheter as compared with the standard catheter (14.5 vs. 10.3 days; 7 vs. 4 treatments; p < 0.03, Fisher-Yates test). Micropatterned surface coating with a polyurethane polymer significantly increased catheter survival and the number of treatments per catheter.