Almost One-Third of Large Sessile Serrated Polyps Are Missed on CT Colonography

BACKGROUND

Nearly one-third of colorectal cancers (CRC) arise via the serrated pathway. CT colonography (CTC) is a CRC screening examination. Endoscopic detection of sessile serrated polyps (SSPs) varies widely; it is unknown whether CTC effectively detects SSPs. The aim of this study is to determine whether CTC detects SSPs at an institution that performs a large volume of CTC.

METHODS

We conducted a search of pathology records to identify serrated polyps (SPs) from 2005 to 2012. We extracted demographic data from the electronic health records (EHRs) of subjects with an SSP and examined endoscopy reports for location and size of each SSP. We identified subjects with a CTC within 1 year prior to the colonoscopy that found an SSP, and determined if the CTC identified the SSP.

RESULTS

Our search found 3978 subjects with SP over the 7-year period. Seven hundred thirty-two subjects had at least 1 SSP. Eightytwo subjects had CTC done within 1 year prior to the colonoscopy that identified SSP. Seventy-nine subjects' polyps were identified on CTC. CT colonography was done an average of 38 ± 54 days prior to colonoscopy. One hundred fifteen SSPs were identified endoscopically. A total of 48.7% of all SSPs were identified via CTC; larger SSPs were more likely to be seen on CTC (P < .001), and 69.6% of SSPs larger than 10 mm were found via CTC. Proximal SSPs were more often identified than distal SSPs (P = .005).

CONCLUSION

Given the miss rate for SSPs on CTC, endoscopists should be vigilant about examining the proximal colon in subjects referred after CTC, even if the imaging does not reveal a proximal polyp.

Lower Annual Rate of Progression of Short-Segment vs Long-Segment Barrett's Esophagus to Esophageal Adenocarcinoma

BACKGROUND & AIMS

European guidelines recommend different surveillance intervals of non-dysplastic Barrett's esophagus (NDBE) based on segment length, as opposed to guidelines in the United States, which do recommend surveillance intervals based on BE length. We studied rates of progression of NDBE to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in patients with short-segment BE using the definition of BE in the latest guidelines (length ≥1 cm).

METHODS

We collected demographic, clinical, endoscopy, and histopathology data from 1883 patients with endoscopic evidence of NDBE (mean age, 57.3 years; 83.5% male; 88.1% Caucasians) seen at 7 tertiary referral centers. Patients were followed for a median 6.4 years. Cases of dysplasia or EAC detected within 1 year of index endoscopy were considered prevalent and were excluded. Unadjusted rates of progression to HGD or EAC were compared between patients with short (≥1 and <3) and long (≥3) BE lengths using log-rank tests. A subgroup analysis was performed on patients with a documented Prague C&M classification. We used a multivariable proportional hazards model to evaluate the association between BE length and progression. Adjusted hazards ratios were calculated after adjusting for variables associated with progression.

RESULTS

We found 822 patients to have a short-segment BE (SSBE) and 1061 to have long segment BE (LSBE). We found patients with SSBE to have a significantly lower annual rate of progression to EAC (0.07%) than of patients with LSBE (0.25%) (P = .001). For the combined endpoint of HGD or EAC, annual progression rates were significantly lower among patients with SSBE (0.29%) compared to compared to LSBE (0.91%) (P < .001). This effect persisted in multivariable analysis (hazard ratio, 0.32; 95% CI, 0.18-0.57; P < .001).

CONCLUSION

We analyzed progression of BE (length ≥1 cm) to HGD or EAC in a large cohort of patients seen at multiple centers and followed for a median 6.4 years. We found a lower annual rate of progression of SSBE to EAC (0.07%/year) than of LSBE (0.25%/year). We propose lengthening current surveillance intervals for patients with SSBE.

Increasing prevalence of high-grade dysplasia and adenocarcinoma on index endoscopy in Barrett's esophagus over the past 2 decades: data from a multicenter U.S. consortium

INTRODUCTION

Data on time trends of dysplasia and esophageal adenocarcinoma (EAC) in Barrett's esophagus (BE) during the index endoscopy (ie, prevalent cases) are limited. Our aim was to determine the prevalence patterns of BE-associated dysplasia on index endoscopy over the past 25 years.

METHODS

The Barrett's Esophagus Study is a multicenter outcome project of a large cohort of patients with BE. Proportions of patients with index endoscopy findings of no dysplasia (NDBE), low-grade dysplasia (LGD), high-grade dysplasia (HGD), and EAC were extracted per year of index endoscopy, and 5-yearly patient cohorts were tabulated over years 1990 to 2010+ (2010-current). Prevalent dysplasia and endoscopic findings were trended over the past 25 years using percentage dysplasia (LGD, HGD, EAC, and HGD/EAC) to assess changes in detection of BE-associated dysplasia over the last 25 years. Statistical analysis was done using SAS version 9.4 software (SAS, Cary, NC).

RESULTS

A total of 3643 patients were included in the analysis with index endoscopy showing NDBE in 2513 (70.1%), LGD in 412 (11.5%), HGD in 193 (5.4%), and EAC in 181 (5.1%). Over time, there was an increase in the mean age of patients with BE (51.7 ± 29 years vs 62.6 ± 11.3 years) and the proportion of males (84% vs 92.6%) diagnosed with BE but a decrease in the mean BE length (4.4±4.3 cm vs 2.9±3.0 cm) as time progressed (1990-1994 to 2010-2016 time periods). The presence of LGD on index endoscopy remained stable over 1990 to 2016. However, a significant increase (148% in HGD and 112% in EAC) in the diagnosis of HGD, EAC, and HGD/EAC was noted on index endoscopy over the last 25 years (P < .001). There was also a significant increase in the detection of visible lesions on index endoscopy (1990-1994, 5.1%; to 2005-2009, 6.3%; and 2010+, 16.3%) during the same period.

CONCLUSION

Our results suggest that the prevalence of HGD and EAC has significantly increased over the past 25 years despite a decrease in BE length during the same period. This increase parallels an increase in the detection of visible lesions, suggesting that a careful examination at the index examination is crucial.

Identifying and Treating Ascending Cholangitis: A case report and review of literature

Acute cholangitis is an infection of the biliary system that typically results from obstruction. Common causes include choledocholithiasis, strictures, foreign bodies (such as biliary stents) parasitic worms (e.g. ascarids) and compression from an external structure. Obstruction allows for higher bacterial concentrations and bacterial proliferation. With biliary stasis and increases in intraductal pressure, bacteria migrate into the venous and lymphatic systems with subsequent bacteremia. The rate of gallstone development is 3-4 % annually in those >60 years old with up to a 15% overall prevalence in the US. In the US, 85% of ascending cholangitis cases are a consequence of choledocholithiasis. The gram-negative bacteria E coli, Klebsiella, Pseudomonas and Enterobacter are the most commonly identified pathogens. Anaerobes are less common.Ascending cholangitis is classically diagnosed by the presence of Charcot’s triad – fever, right upper quadrant pain and jaundice. Though very specific, the presence of Charcot’s triad is only 26% sensitive and thus its absence does not rule out the diagnosis. All patients with suspected ascending cholangitis should undergo appropriate fluid resuscitation, be given broad spectrum antibiotics to cover the likely enteric pathogens, and closely monitored for worsening in their clinical condition.Once initial assessment is complete and resuscitative efforts begun, imaging is often helpful in confirming the diagnosis of ascending cholangitis. After the diagnosis has been confirmed, ERCP and biliary drainage is indicated.

Identifying and Treating Ascending Cholangitis. A case report and review of literature

Acute cholangitis is an infection of the biliary system that typically results from obstruction. Common causes include choledocholithiasis, strictures, foreign bodies (such as biliary stents) parasitic worms (e.g. ascarids) and compression from an external structure. Obstruction allows for higher bacterial concentrations and bacterial proliferation. With biliary stasis and increases in intraductal pressure, bacteria migrate into the venous and lymphatic systems with subsequent bacteremia. The rate of gallstone development is 3-4 % annually in those >60 years old with up to a 15% overall prevalence in the US. In the US, 85% of ascending cholangitis cases are a consequence of choledocholithiasis. The gram-negative bacteria E coli, Klebsiella, Pseudomonas and Enterobacter are the most commonly identified pathogens. Anaerobes are less common.Ascending cholangitis is classically diagnosed by the presence of Charcot’s triad – fever, right upper quadrant pain and jaundice. Though very specific, the presence of Charcot’s triad is only 26% sensitive and thus its absence does not rule out the diagnosis. All patients with suspected ascending cholangitis should undergo appropriate fluid resuscitation, be given broad spectrum antibiotics to cover the likely enteric pathogens, and closely monitored for worsening in their clinical condition.Once initial assessment is complete and resuscitative efforts begun, imaging is often helpful in confirming the diagnosis of ascending cholangitis. After the diagnosis has been confirmed, ERCP and biliary drainage is indicated.

Factors influencing decisions about a career in hepatology: A survey of gastroenterology fellows

Despite an unmet need for hepatologists in the United States, every year transplant hepatology (TH) fellowship positions remain unfilled. To address this, we investigated factors that influence trainee decisions about pursuing a career in hepatology. We invited current gastroenterology (GI) and TH fellows from all Accreditation Council for Graduate Medical Education‐accredited programs for the academic year 2014‐2015 to participate in an online survey about factors influencing decisions to train in hepatology. The same paper‐based survey was distributed at a nationally recognized GI board review course. The survey was completed by 180 participants of which 91% were current GI or TH fellows and 24% were not aware of the pilot 3‐year combined GI and TH training program. A majority of respondents (57%) reported that a shorter time (3 versus 4 years) to become board certification eligible would influence their decisions to pursue TH. The most common reasons for not pursuing hepatology were less endoscopy time (67%), additional length of training (64%), and lack of financial compensation (44%). Personal satisfaction (66%), management of complex multisystem disease (60%), and long‐term relationships with patients (57%) were the most attractive factors. Sixty‐one percent of participants reported having a mentor, and 94% of those with mentors reported that their mentors influenced their career decisions. Conclusion: We have identified several factors that affect fellows' decision to pursue TH. Shorter training, increased financial compensation, and increased endoscopy time are potentially modifiable factors that may increase the number of trainees seeking careers in hepatology and help alleviate the deficit of hepatologists. (Hepatology Communications 2017;1:347–353)

Barrett's oesophagus length is established at the time of initial endoscopy and does not change over time: results from a large multicentre cohort

OBJECTIVE

It is unclear whether Barrett's oesophagus (BO) length changes over time or whether the full length of the segment is established at the onset of disease recognition. The objectives of this study were to evaluate the association of age and BO length and to evaluate the changes in BO length over time.

DESIGN

This is a prospective, multicentre cohort study involving patients with BO from five centres. Patients were divided into groups based on the decade of initial diagnosis of BO. The mean BO length and the mean change in BO length were calculated for each age decade. The mean change in BO length was also calculated between the index endoscopy and the last surveillance endoscopy.

RESULTS

3635 patients with BO were included in the study: 87.8% men, 92.8% Caucasians, mean age 60.9 years and mean BO length 3.5 cm. The mean change in BO length was 0.9 cm. The mean BO length did not significantly change for each age category: <30 years (4.6 cm), 30-39.9 years (3.2 cm), 40-49.9 years (3.1 cm), 50-59.9 years (3.1 cm), 60-69.9 years (3.6 cm), 70-79.7 (4.0 cm) and >80 years (4.5 cm), p=0.47. On subgroup analysis of patients with non-dysplastic BO who had at least 1 year of endoscopic follow up, there was a significant decrease in mean change in BO length across age categories ranging from +1.7 to -0.8 cm, p=0.03.

CONCLUSIONS

There was no significant difference in BO length by age category in decades. In addition, the change in BO length from index to follow-up endoscopy was similar among patients >30 years. These findings suggest that a patient's BO segment length attains its full extent by the time of the initial endoscopic examination.

Influence of provider discussion and specific recommendation on colorectal cancer screening uptake among U.S. adults

OBJECTIVES

It is unclear if provider recommendations regarding colorectal cancer (CRC) screening modalities affect patient compliance. We evaluated provider-patient communications about CRC screening with and without a specific screening modality recommendation on patient compliance with screening guidelines.

METHODS

We used the 2007 Health Information National Trends Survey (HINTS) and identified 4283 respondents who were at least 50 years of age and answered questions about their communication with their care providers and CRC screening uptake. We defined being compliant with CRC screening as the use of fecal occult blood testing (FOBT) within 1 year, sigmoidoscopy within 5 years, or colonoscopy within 10 years. We used survey weights in all analyses.

RESULTS

CRC screening discussions occurred with 3320 (76.2%) respondents. Approximately 95% of these discussions were with physicians. Overall, 2793 (62.6%) respondents were current with CRC screening regardless of the screening modality. Discussion about screening (odds ratio (OR)=8.83; 95% confidence interval (CI): 7.20-10.84) and providers making a specific recommendation about screening modality rather than leaving it to the patient to decide (OR=2.04; 95% CI: 1.54-2.68) were associated with patient compliance with CRC screening guidelines.

CONCLUSION

Compliance with CRC screening guidelines is improved when providers discuss options and make specific screening test recommendations.

Global changes in gene expression of Barrett's esophagus compared to normal squamous esophagus and gastric cardia tissues

BACKGROUND

Barrett's esophagus (BE) is a metaplastic precursor lesion of esophageal adenocarcinoma (EA), the most rapidly increasing cancer in western societies. While the prevalence of BE is increasing, the vast majority of EA occurs in patients with undiagnosed BE. Thus, we sought to identify genes that are altered in BE compared to the normal mucosa of the esophagus, and which may be potential biomarkers for the development or diagnosis of BE.

DESIGN

We performed gene expression analysis using HG-U133A Affymetrix chips on fresh frozen tissue samples of Barrett's metaplasia and matched normal mucosa from squamous esophagus (NE) and gastric cardia (NC) in 40 BE patients.

RESULTS

Using a cut off of 2-fold and P<1.12E-06 (0.05 with Bonferroni correction), we identified 1324 differentially-expressed genes comparing BE vs NE and 649 differentially-expressed genes comparing BE vs NC. Except for individual genes such as the SOXs and PROM1 that were dysregulated only in BE vs NE, we found a subset of genes (n = 205) whose expression was significantly altered in both BE vs NE and BE vs NC. These genes were overrepresented in different pathways, including TGF-β and Notch.

CONCLUSION

Our findings provide additional data on the global transcriptome in BE tissues compared to matched NE and NC tissues which should promote further understanding of the functions and regulatory mechanisms of genes involved in BE development, as well as insight into novel genes that may be useful as potential biomarkers for the diagnosis of BE in the future.

Association between length of Barrett's esophagus and risk of high-grade dysplasia or adenocarcinoma in patients without dysplasia

BACKGROUND & AIMS

It is not clear whether length of Barrett's esophagus (BE) is a risk factor for high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in patients with nondysplastic BE. We studied the risk of progression to HGD or EAC in patients with nondysplastic BE, based on segment length.

METHODS

We analyzed data from a large cohort of patients participating in the BE Study-a multicenter outcomes project comprising 5 US tertiary care referral centers. Histologic changes were graded as low-grade dysplasia, HGD, or EAC. The study included patients with BE of documented length without dysplasia and at least 1 year of follow-up evaluation (n = 1175; 88% male), and excluded patients who developed HGD or EAC within 1 year of their BE diagnosis. The mean follow-up period was 5.5 y (6463 patient-years). The annual risk of HGD and EAC was plotted in 3-cm increments (≤3 cm, 4-6 cm, 7-9 cm, 10-12 cm, and ≥13 cm). We calculated the association between time to progression and length of BE.

RESULTS

The mean BE length was 3.6 cm; 44 patients developed HGD or EAC, with an annual incidence rate of 0.67%/y. Compared with nonprogressors, patients who developed HGD or EAC had longer BE segments (6.1 vs 3.5 cm; P < .001). Logistic regression analysis showed a 28% increase in risk of HGD or EAC for every 1-cm increase in BE length (P = .01). Patients with BE segment lengths of 3 cm or shorter took longer to develop HGD or EAC than those with lengths longer than 4 cm (6 vs 4 y; P = nonsignificant).

CONCLUSIONS

In patients with BE without dysplasia, length of BE was associated with progression to HGD or EAC. The results support the development of a risk stratification scheme for these patients based on length of BE segment.

Persistence of nondysplastic Barrett's esophagus identifies patients at lower risk for esophageal adenocarcinoma: results from a large multicenter cohort

BACKGROUND & AIMS

Recent population-based studies have shown a low risk of esophageal adenocarcinoma (EAC) in patients with nondysplastic Barrett's esophagus (NDBE). We evaluated whether persistence of NDBE over multiple consecutive surveillance endoscopic examinations could be used in risk stratification of patients with Barrett's esophagus (BE).

METHODS

We performed a multicenter outcomes study of a large cohort of patients with BE. Based on the number of consecutive surveillance endoscopies showing NDBE, we identified 5 groups of patients. Patients in group 1 were found to have NDBE at their first esophagogastroduodenoscopy (EGD). Patients in group 2 were found to have NDBE on their first 2 consecutive EGDs. Similarly, patients in groups 3, 4, and 5 were found to have NDBE on 3, 4, and 5 consecutive surveillance EGDs. A logistic regression model was built to determine whether persistence of NDBE independently protected against development of cancer.

RESULTS

Of a total of 3515 patients with BE, 1401 patients met the inclusion criteria (93.3% white; 87.5% men; median age, 60 ±17 years). The median follow-up period was 5 ± 3.9 years (7846 patient-years). The annual risk of EAC in groups 1 to 5 was 0.32%, 0.27%, 0.16%, 0.2%, and 0.11%, respectively (P for trend = .03). After adjusting for age, sex, and length of BE, persistence of NDBE, based on multiple surveillance endoscopies, was associated with a gradually lower likelihood of progression to EAC.

CONCLUSIONS

Persistence of NDBE over several endoscopic examinations identifies patients who are at low risk for development of EAC. These findings support lengthening surveillance intervals or discontinuing surveillance of patients with persistent NDBE.

Colonoscopy for colorectal cancer screening

Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. Many, if not most, cases arise from premalignant lesions (adenomas) which may be identified and removed prior to becoming frankly malignant. For over a decade, colonoscopy has been the preferred modality for both CRC screening and prevention in the US. Early reports suggested that colonoscopic screening imparted a 90% risk reduction for colorectal cancer. Subsequent studies showed that estimate to be overly optimistic. While still an outstanding CRC screening and detection tool, colonoscopy has several important limitations. Some of these limitations relate to the mechanics of the procedure such as the risk of colonic perforation, bleeding, adverse consequences of sedation, and the inability to detect all colonic polyps. Other limitations reflect issues with patient perception regarding colonoscopy which, at least in part, drive patient non-adherence to recommended testing. This review examines the literature to address several important issues. First, we analyze the effect of colonoscopy on CRC incidence and mortality. Second, we consider the patient-based, periprocedural, and intraprocedural factors which may limit colonoscopy as a screening modality. Third, we explore new techniques and technologies which may enhance the efficacy of colonoscopy for adenoma detection. Finally, we discuss the short and long-term future of colonoscopy for CRC screening and the factors which may affect this future.

Probiotics for the treatment of inflammatory bowel disease

Probiotics are organisms which provide a desired and beneficial effect on human health. With recent evidence implicating a disruption in the balance of the gastrointestinal microbiome and intestinal immunity as a potential trigger for inflammatory bowel disease (IBD), there has been growing interest in using probiotics as an adjunct to standard anti-inflammatory and immune suppressing therapy. Animal models describe potential and plausible mechanisms of action for probiotics to counter inflammation of colonic mucosa. Although there are insufficient data to recommend probiotics in ulcerative colitis or Crohn's disease, good evidence supports the use of specific probiotics for maintenance of remission in pouchitis. Although there are limited regulatory standards for the agents, probiotics are relatively safe with minimal reported side effects or contraindications. More rigorous studies need to be published supporting efficacy and safety of these agents before they become a mainstay of IBD medical treatment.

The prevalence of celiac disease among patients with nonconstipated irritable bowel syndrome is similar to controls

BACKGROUND & AIMS

Guidelines recommend that patients with symptoms of nonconstipated irritable bowel syndrome (NC-IBS) undergo testing for celiac disease (CD). We evaluated the prevalence of CD antibodies, and biopsy confirmed CD among patients with NC-IBS in a large US population.

METHODS

In a study conducted at 4 sites, from 2003 to 2008, we compared data from 492 patients with symptoms of NC-IBS to 458 asymptomatic individuals who underwent colonoscopy examinations for cancer screening or polyp surveillance (controls). All participants provided blood samples for specific and nonspecific CD-associated antibodies. Additionally, patients with IBS were analyzed for complete blood cell counts, metabolic factors, erythrocyte sedimentation rates, and levels of C-reactive protein and thyroid-stimulating hormone. Any subjects found to have CD-associated antibodies were offered esophagogastroduodenoscopy and duodenal biopsy analysis.

RESULTS

Of patients with NC-IBS, 7.3% had abnormal results for CD-associated antibodies, compared with 4.8% of controls (adjusted odds ratio, 1.49; 95% confidence interval: 0.76-2.90; P=.25). Within the NC-IBS group, 6.51% had antibodies against gliadin, 1.22% against tissue transglutaminase, and 0.61% against endomysium (P>.05 vs controls for all antibodies tested). CD was confirmed in 0.41% of patients in the NC-IBS group and 0.44% of controls (P>.99).

CONCLUSIONS

Although CD-associated antibodies are relatively common, the prevalence of CD among patients with NC-IBS is similar to that among controls in a large US population. These findings challenge recommendations to routinely screen patients with NC-IBS for CD. More than 7% of patients with NC-IBS had CD-associated antibodies, suggesting that gluten sensitivity might mediate IBS symptoms; further studies are needed.

Endoscopic ultrasound does not accurately stage early adenocarcinoma or high-grade dysplasia of the esophagus

BACKGROUND & AIMS

Patients with esophageal high-grade dysplasia or mucosal esophageal cancer can be successfully treated by endoscopy. We performed a systematic review of the literature to determine whether endoscopic ultrasound (EUS) correctly predicts the T-stage of early esophageal cancers, compared with pathology specimens obtained by using endoscopic mucosal resection (EMR) or surgery.

METHODS

Standard systematic review methods were used to perform reference searches, determine eligibility, abstract data, and analyze data. When possible, individual patient-level data were abstracted, in addition to publication-level aggregate data.

RESULTS

Twelve studies had sufficient information to abstract and review for quality; 8 had individual patient-level data (n = 132). Compared with surgical or EMR pathology staging, EUS had T-stage concordance of 65%, including all studies (n = 12), but only 56% concordance when limited to individual patient-level data. Factors such as initial biopsy pathology (high-grade dysplasia vs early-stage cancer) did not appear to affect the concordance of staging between EUS and EMR/surgical staging.

CONCLUSIONS

EUS is not sufficiently accurate in determining the T-stage of high-grade dysplasias or superficial adenocarcinomas; other means of staging, such as EMR, should be used.

Long duration backlighter experiments at Omega

We have successfully demonstrated a 7.5 ns duration pinhole-apertured backlighter at the Omega laser facility. Pinhole-apertured point-projection backlighting for 8 ns will be useful for imaging evolving features in experiments at the National Ignition Facility. The backlighter consisted of a 20 microm diameter pinhole in a 75 microm thick Ta substrate separated from a Zn emitter (9 keV) by a 400 microm thick high-density carbon piece. The carbon prevented the shock from the laser-driven surface from reaching the substrate before 8 ns and helped minimize x-ray ablation of the pinhole substrate. Grid wires in x-ray framing camera images of a gold grid have a source-limited resolution significantly smaller than the pinhole diameter due to the high aspect ratio of the pinhole, but do not become much smaller at late times.

Psychogenic coma following upper endoscopy: a case report and review of the literature

BACKGROUND

Failure to regain consciousness after general anesthesia has a multitude of life-threatening causes, including neurological injury, metabolic derangements, or drug effects. Failure to promptly recognize the cause of unconsciousness after anesthesia can result in significant patient morbidity or mortality, costly laboratory and radiographic evaluation, and physician anxiety. Rarely, patients fail to awaken after anesthesia due to a psychiatric cause. The early recognition of psychogenic coma can result in reduced iatrogenic complications, hospital cost, and physician anxiety.

CASE

We present a case of a 28-year-old female who became unresponsive after general anesthesia for an upper endoscopy. Physical, laboratory, and radiographic examination after the procedure revealed no apparent organic cause for her failure to awaken. The patient spontaneously awoke after 16 hours without neurological deficit.

DISCUSSION

We reviewed the literature and identified 10 previously reported cases of postanesthesia psychogenic coma. We have compared and contrasted our case with the 10 previous reports and propose bedside clues to assist the physician with diagnosing this unusual condition.

Demonstration of the density dependence of x-ray flux in a laser-driven hohlraum

Experiments have been conducted using laser-driven cylindrical hohlraums whose walls are machined from Ta2O5 foams of 100 mg/cc and 4 g/cc densities. Measurements of the radiation temperature demonstrate that the lower density walls produce higher radiation temperatures than the high density walls. This is the first experimental demonstration of the prediction that this would occur [M. D. Rosen and J. H. Hammer, Phys. Rev. E 72, 056403 (2005)10.1103/PhysRevE.72.056403]. For high density walls, the radiation front propagates subsonically, and part of the absorbed energy is wasted by the flow kinetic energy. For the lower wall density, the front velocity is supersonic and can devote almost all of the absorbed energy to heating the wall.

The utility of flexible sigmoidoscopy after a computerized tomographic colonography revealing only rectosigmoid lesions

BACKGROUND

Identifying polyps by computerized tomographic colonography typically prompts colonoscopy, increasing its cost, risk and inconvenience. Many polyps are confined to the rectosigmoid and theoretically amenable to resection via flexible sigmoidoscopy.

AIM

To determine the prevalence of advanced proximal colonic neoplasia when computerized tomographic colonography reveals only rectosigmoid polyps, and characterize the yield of polypectomy via flexible sigmoidoscopy in such patients.

METHODS

Subjects underwent computerized tomographic colonography and colonoscopy with segmental unblinding. Patients with only rectosigmoid findings by computerized tomographic colonography were identified retrospectively. Flexible sigmoidoscopy findings were estimated by including lesions distal to the descending/sigmoid colon junction during colonoscopy. Proximal lesions were also reviewed. Advanced lesions were defined as: adenocarcinoma, tubular adenoma >1 cm, > or =3 tubular adenomas, tubulovillous histology or high-grade dysplasia.

RESULTS

By computerized tomographic colonography, 15% (203 of 1372) had only rectosigmoid polyps. Concomitant lesions in the proximal colon were seen in 32% (64 of 203) during colonoscopy. Advanced proximal neoplasia occurred in 2% (three of 203) with only rectosigmoid polyps on computerized tomographic colonography.

CONCLUSIONS

Using flexible sigmoidoscopy to follow-up computerized tomographic colonography demonstrating only rectosigmoid polyps would eliminate 15% of subsequent colonoscopies. This strategy carries a small risk of missed proximal advanced neoplasia. This miss rate appears comparable to that of colonoscopy alone. Further study on the cost-effectiveness of this approach is warranted.

A comparison of two sphygmomanometers that may replace the traditional mercury column in the healthcare workplace

OBJECTIVE

Alternatives to the traditional, but possibly toxic mercury sphygmomanometer are needed for accurate blood pressure measurements in the medical workplace. We compared the performance of two commercially available potential replacements for the mercury column; an anaeroid manometer (Baum & Co) and an automated oscillometric device (Omron HEM-907), using the mercury sphygmomanometer as a standard, in the same participants.

METHODS

Two independent observers performed simultaneous triplicate blood pressure readings for 512 participants. The average difference and standard deviation of the difference comparing the mercury column vs. the anaeroid and automated devices were calculated for each of the three paired systolic and diastolic blood pressure readings.

RESULTS

Both devices met the Association for the Advancement of Medical Instrumentation criteria for sphygmomanometers (<5 mmHg average difference, <8 mmHg standard deviation of the difference) for all three readings. Compared with the mercury standard, there were no significant differences (by paired t-test) with the anaeroid device (-0.83/0.73 mmHg, P=0.25/0.09), but the automated device slightly overestimated systolic blood pressure (by 2.12 mmHg, P=0.002) and underestimated diastolic blood pressure (by 2.36 mmHg, P=0.0002). The first reading was significantly higher and had a larger standard deviation than the second or third readings across all manometers.

CONCLUSIONS

The automated device performed as well as an anaeroid manometer operated by well trained, experienced observers. The two alternative devices to the mercury sphygmomanometer examined in this study may be potential replacement devices for blood pressure measurement.

High-speed horizontal-path atmospheric turbulence correction with a large-actuator-number microelectromechanical system spatial light modulator in an interferometric phase-conjugation engine

Results of atmospheric propagation for a high-speed, large-actuator-number adaptive optics system are presented. The system uses a microelectromechanical system- (MEMS-) based spatial light modulator correction device with 1024 actuators. Tests over a 1.35-km path achieved correction speeds in excess of 800 Hz and Strehl ratios close to 0.5. The wave-front sensor was based on a quadrature interferometer that directly measures phase. This technique does not require global wave-front reconstruction, making it relatively insensitive to scintillation and phase residues. The results demonstrate the potential of large-actuator-number MEMS-based spatial light modulators to replace conventional deformable mirrors.

Performance of a phase-conjugate engine implementing a finite-bit phase correction

The achievable Strehl ratio when a finite-bit correction to an aberrated wave front is implemented is examined. The phase-conjugate engine used to measure the aberrated wave front consists of a quadrature interferometric wave-front sensor, a liquid-crystal spatial light modulator, and computer hardware-software to calculate and apply the correction. A finite-bit approximation to the conjugate phase is calculated and applied to the spatial light modulator to remove the aberrations from the optical beam. The experimentally determined Strehl ratio of the corrected beam is compared with analytical expressions for the expected Strehl ratio and shown to be in good agreement with those predictions.

Investigation of the onset and development of forward scattering in an underdense plasma

We investigate the distortion of a spatial intensity modulation imposed on a 527 nm f/10 probe beam as it transmits through an underdense plasma characterized with Thomson scattering. Combining the measurements with full wave simulations of beam propagation through the entire plasma show that the key features of the data can be reproduced using the Kaiser thermal transport model.

Observation of saturation of energy transfer between copropagating beams in a flowing plasma

Experiments demonstrate energy and power transfer between copropagating, same frequency, beams crossing at a small angle in a plasma with a Mach 1 flow. The process is interpreted as amplification of the low intensity probe beam by the stimulated scatter of the high intensity pump beam. The observed probe amplification increases slowly with pump intensity and decreases with probe intensity, indicative of saturation limiting the energy and power transfer due to ion-wave nonlinearities and localized pump depletion. The results are consistent with numerical modeling including ion-wave nonlinearities.

K-shell spectroscopy of an independently diagnosed uniaxially expanding laser-produced aluminum plasma

We present detailed spectroscopic analysis of the primary K-shell emission lines from a uniaxially expanding laser-produced hydrogenic and heliumlike aluminum plasma. The spectroscopic measurements are found to be consistent with time-dependent hydrodynamic properties of the plasma, measured using Thomson scattering and shadowgraphy. The K-shell population kinetics code FLY with the measured hydrodynamic parameters is used to generate spectra that are compared to the experimental spectra. Excellent agreement is found between the measured and calculated spectra for a variety of experimental target widths employed to produce plasmas with different optical depths. The peak emission from the hydrogenic Lyman series is determined to be from a temporal and spatial region where the hydrodynamic parameters are essentially constant. This allows a single steady-state solution of FLY to be used to deduce the electron temperature and density, from the measured line ratios and linewidths, for comparison with the Thomson and shadowgraphy data. These measurements are found to agree well with time-dependent calculations, and provide further validation for the FLY calculations of the ionization and excitation balance for a K-shell aluminum plasma. We also discuss the possible application of this data as a benchmark for hydrodynamic simulations and ionization/excitation balance calculations.

Human APC2 localization and allelic imbalance

A second adenomatous polyposis coli (APC)-like gene, APC2/APCL, was recently described and localized to chromosome 19. We have fine mapped APC2 to a small region of chromosome 19p13.3 containing markers D19S883 and WI-19632, a region commonly lost in a variety of cancers, particularly ovarian cancer. Interphase fluorescence in situ hybridization analysis revealed an APC2 allelic imbalance in 19 of 20 ovarian cancers screened and indicates that APC2 could be a potential tumor suppressor gene in ovarian cancer. When overexpressed in SKOV3 ovarian cancer cells, which express low levels of APC2, exogenous APC2 localized to the Golgi apparatus, actin-containing structures, and occasionally to microtubules. Antibodies against the NH2 terminus of human APC2 show that endogenous APC2 is diffusely distributed in the cytoplasm and colocalizes with both the Golgi apparatus and actin filaments. APC2 remained associated with actin filaments after treatment with the actin-disrupting agent, cytochalasin D. These results suggest that APC2 is involved in actin-associated events and could influence cell motility or adhesion through interaction with actin filaments, as well as functioning independently or in cooperation with APC to down-regulate beta-catenin signaling.

Backscatter reduction using combined spatial, temporal, and polarization beam smoothing in a long-scale-length laser plasma

Spatial, temporal, and polarization smoothing schemes are combined for the first time to reduce to a few percent the total stimulated backscatter of a NIF-like probe laser beam (2x10(15) W/cm (2), 351 nm, f/8) in a long-scale-length laser plasma. Combining temporal and polarization smoothing reduces simulated Brillouin scattering and simulated Raman scattering (SRS) up to an order of magnitude although neither smoothing scheme by itself is uniformly effective. The results agree with trends observed in simulations performed with the laser-plasma interaction code F3D simulations [R. L. Berger et al., Phys. Plasma 6, 1043 (1999)].

Thomson scattering measurements of saturated ion waves in laser fusion plasmas

We have measured the characteristics of saturated ion-acoustic waves in inertial confinement fusion plasmas. A 263-nm probe laser has been applied to simultaneous Thomson scatter on both ion-acoustic waves excited by thermal electrostatic fluctuations and by stimulated Brillouin scattering of a kilojoule laser beam of varying intensity. The Thomson scattering spectra show saturated ion-wave amplitudes for intensities above 5x10(14) W cm(-2) consistent with three dimensional nonlinear wave modeling.

A new short practical quality of life questionnaire for use in head and neck oncology outpatient clinics

A new short questionnaire to assess the quality of life of head and neck patients has been designed at the University of Liverpool Head and Neck Oncology Department. The questionnaire is short, simple and can be easily completed by a patient whilst in the waiting room before consultation. It is filled in 6 months after completion of treatment and shows very good correlation with the standard long exhaustive questionnaires that are difficult to complete on every patient in a busy National Health Service clinic. The University of Liverpool questionnaire provides a simple score from 0%-100% which should prove valuable in the assessment of quality of care and help with decisions regarding treatment options in head and neck cancer patients.

NRG-3 in human breast cancers: activation of multiple erbB family proteins

Ligands of the EGF/Heregulin family control the growth of epithelial cells by binding to receptors of the erbB family. By searching a large database of cDNA sequences at Human Genome Sciences Inc. we have identified a new encoded protein sequence containing all the conserved elements of the EGF/Heregulin family. The same sequence has recently been independently identified as NRG-3. The EGF-like domain of NRG-3 was generated as a recombinant protein in E. coli and used to test the specificity of receptor binding. In human breast cancer cells and in 32D cells transfected by erbB family members, NRG-3 activated multiple erbB family members. These include EGF receptor (erbB1) and erbB4 when expressed individually and erbB2 and erbB3 when expressed together. Recombinant NRG-3 altered the growth of human breast cancer cells growing in vitro. NRG-3 was expressed in cell lines derived from breast cancer. These results indicate that NRG-3 is a potential regulator of normal and malignant breast epithelial cells in vivo.

Occult abdominal injuries to airbag-protected crash victims: a challenge to trauma systems

A multidisciplinary, automobile crash investigation team at the University of Miami School of Medicine, William Lehman Injury Research Center of Jackson Memorial Hospital/Ryder Trauma Center in Miami, Florida, is conducting a detailed medical and engineering study. The focus is restrained (seatbelts, airbag, or both) occupants involved in frontal crashes who have been severely injured. More than 60 crashes have been included in the study to date. Analysis of the initial data supports the general conclusion that restraint systems are working to reduce many of the head and chest injuries suffered by unrestrained occupants. However, abdominal injuries among airbag-protected occupants still occur. Some are found among occupants who appeared uninjured at the scene. Case examples are provided to illustrate abdominal injuries associated with airbag-protected crashes. The challenges of recognizing injuries to airbag-protected occupants are discussed. To assist in recognizing the extent of injuries to occupants protected by airbags, it is suggested that evidence from the crash scene be used in the triage decision. For the abdominal injury cases observed in this study, deformation of the steering system was the vehicle characteristic most frequently observed. The presence of steering wheel deformation is an indicator of increased likelihood of internal injury. This may justify transporting the victim to a trauma center for a closer examination for abdominal injuries.

The sialomucin CD34 is expressed on hematopoietic cells and blood vessels during murine development

The processes of angiogenesis and hematopoiesis require a high degree of coordination during embryogenesis. Whereas much is understood about the development of the vascular system in avian embryos, little information has been attained in mammals, predominantly because there are no specific markers for either blood vessels or hematopoietic cells in any developing mammalian system. We have recently shown that murine CD34 (mCD34) is expressed on the vascular endothelium in all organs and tissues of the adult mouse as well as on a small percentage of presumably hematopoietic stem cells in the bone marrow and fetal liver. Here we show that mCD34 is also expressed on the endothelium of blood vessels and on a subset of hematopoietic-like cells throughout murine development. mCD34 is first observed on the yolk sac endothelium of day 7.5 embryos and on a subset of hematopoietic cells within these yolk sacs. mCD34 expression is maintained on vessels and hematopoietic cells in all organs and tissues throughout embryogenesis. In addition, mCD34 is localized on growth conelike filopodial processes that appear at the budding edge of newly sprouted capillaries. Double staining of capillaries for mCD34 and laminin shows that these growth conelike processes seem to be free of laminin, whereas the formed capillaries seem to be coated with this extracellular matrix protein. Analysis of vessels in developing brain shows that these filopodial processes seem to be directed toward the ventricular epithelium, a previously described site of vascular endothelial growth factor synthesis. Finally, we show that the vascular structures of developing murine embryoid bodies also express mCD34. These data suggest that mCD34 is a useful marker for the analysis of the development of the blood vascular system in murine embryos.