A multicenter validation of an endoscopic classification with narrow band imaging for gastric precancerous and cancerous lesions

BACKGROUND AND STUDY AIM

The reliability and external validity of narrow band imaging (NBI) in the stomach have not been described consistently. The aim of the current study was to describe and estimate the accuracy and reliability of a simplified classification system for NBI in the diagnosis of gastric lesions.

METHODS

Consecutive patients undergoing NBI endoscopy at two reference centers (n=85, 33% with dysplasia) were included in two studies. In total, 224 different areas were biopsied and recorded onto video. In the derivation study, previously described NBI features were analyzed in order to develop a simplified classification. In the validation study the accuracy and reliability of this classification were estimated among three groups of endoscopists with different levels of expertise in NBI.

RESULTS

The reliability/accuracy results from the derivation study allowed the creation of a simplified NBI classification. In the validation study, "regular vessels with circular mucosa" (pattern A) was associated with normal histology (accuracy 83%; 95% confidence interval [CI] 75 %-90%); "tubulo-villous mucosa" (pattern B) was associated with intestinal metaplasia (accuracy 84%; 95CI 77%-91%; positive likelihood ratio [LR+]=4.75); and "irregular vessels and mucosa" (pattern C) was associated with dysplasia (accuracy 95%; 95CI 90%-99%; LR+=44.33). The reproducibility of these patterns was high (k=0.62). "Light-blue crest" was moderately reliable (k=0.49) but specific (87%) for intestinal metaplasia. A variable vascular density (additional pattern+) was the best feature for Helicobacter pylori gastritis (accuracy 70%; 95CI 59%-80%) but showed only fair reliability (k=0.38). Non-experienced endoscopists presented lower agreement (k=0.6 vs. k=0.75) and accuracy (74% vs. 86%) than international experts/experienced endoscopists.

CONCLUSION

A simplified NBI classification is accurate and reliable for the diagnosis of intestinal metaplasia and dysplasia. The classification should be further assessed and validated on a per-patient assessment of NBI, and by comparing NBI with other imaging technologies.

Surface-enhanced Raman spectroscopy analysis of house paint and wallpaper samples from an 18th century historic property

Conservation efforts for heritage buildings require a substantial knowledge of the chemical makeup of materials that were used throughout the lifetime of the property. In particular, conservators are often concerned with the identification of colorants used in both interior and exterior wall treatments (paint, wallpaper, etc.) in order to gain perspective into how the building may have appeared during a certain time period in its existence. Ideally, such an analysis requires a technique that provides molecular level information as to the identity of the colorant as well as other sample components (binders, fillers, etc.), which is useful for dating purposes. In addition, the technique should be easily applied to paint layer samples which can be extremely thin and fragile. Herein we report the surface-enhanced Raman spectroscopy (SERS) analysis of paint and wallpaper samples taken from exterior and interior surfaces of a historic building. Several pigments were identified in the samples, which ranged from early inorganic pigments (lead white, barium sulfate, calcium carbonate, anhydrous chromium(III) oxide) which have been used in house paints for centuries, to a more modern pigment (phthalocyanine blue), developed in the middle of the 20th century. This analysis highlights the usefulness of SERS in such a conservation effort, and demonstrates for the first time pigment identification in house paints and wallpaper using SERS, which has far-reaching implications not only in the field of conservation, but also in forensics, industrial process control, and environmental health and safety.

Hospice utilization by men dying of prostate cancer

9501

Background: The 25,000 American men who die of prostate cancer each year often suffer from fatigue, bone pain, and weight loss. Enrollment in hospice programs improves both the quality of life and the quality of death for this cohort. However, previous data suggest that hospice is often used inappropriately, either through underuse or through improperly timed referral. We sought to characterize sociodemographic and clinical factors that affect appropriate and inappropriate utilization of hospice services by men with metastatic prostate cancer in a population-based dataset. Methods: We used linked data from Surveillance, Epidemiology, and End Results and Medicare data to identify a cohort of beneficiaries who died of prostate cancer between 1992 and 2005. We then evaluated the bivariate association between sociodemographic and clinical data and any hospice enrollment. Hospice referrals within 7 days of death or more than 180 days before dying were considered inappropriate. Results: Of the 14,521 men dying of prostate cancer, 7,646 (53%) utilized hospice resources. Enrollment within 7 days of death was noted in 1699 subjects (22% of hospice users), and enrollment more than 180 days prior to death was seen in 717 participants (9% of hospice users). Subjects who utilized hospice within the appropriate time frame were enrolled for a mean of 47 days (S.D. 41, range 7–180 days) prior to death, with a median of 31 days. In our bivariate analysis, white ethnicity, partnered status, and achieving at least a high school diploma were significantly associated with hospice use ( Table ). Conclusions: Hospice utilization rates in our cohort compared favorably with previous analyses, but the frequency of improperly timed hospice referrals was similar to prior reports and provides an opportunity for improvement.

[Table: see text]

No significant financial relationships to disclose.

Complications of laparoscopic renal surgery

Initial excitement for laparoscopy's potential to decrease patient morbidity and convalescence by avoiding a flank incision was initially tempered by concerns for increased operative time, technical complexity and the suitability of laparoscopy approaches to oncologic surgery. With experience, the benefits of laparoscopic approaches to renal surgery have become clear. As laparoscopic techniques are mastered and the indications expanded, it is important to remember that minimally invasive surgery remains associated with significant risks and potential complications. Several complications are theoretically more difficult to control laparoscopically than with open exposure. Control of bleeding, identification of injury to solid organs, and positive margins due to the lack of haptic feedback have been of special concern during the rapid advancement of laparoscopic surgical technique between 1991 and today. It is critical for the urologist to be familiar with these complications in order to maximize patients' clinical outcomes through appropriate patient selection and intraoperative planning. Know-ledge of the complications of laparoscopic renal surgery will also aid in providing patients with true informed consent and realistic surgical expectations. The purpose of this manuscript is to review the complications associated with laparoscopic renal surgery in general, with specific attention paid to laparoscopic radical, partial, pediatric, and donor nephrectomy.

Utilization of photon orbital angular momentum in the low-frequency radio domain

We show numerically that vector antenna arrays can generate radio beams that exhibit spin and orbital angular momentum characteristics similar to those of helical Laguerre-Gauss laser beams in paraxial optics. For low frequencies (< or = 1 GHz), digital techniques can be used to coherently measure the instantaneous, local field vectors and to manipulate them in software. This enables new types of experiments that go beyond what is possible in optics. It allows information-rich radio astronomy and paves the way for novel wireless communication concepts.