Is Blepharoplasty Cost-effective? Utility Analysis of Dermatochalasis and Cost-effectiveness Analysis of Upper Eyelid Blepharoplasty

PURPOSE

This cross-sectional prospective study measured utility values of upper eyelid dermatochalasis to quantify its impact on quality of life and assess cost-effectiveness of upper blepharoplasty.

METHODS

Utility of dermatochalasis was assessed using the standard reference gamble and time trade-off methods, with dual anchor points of perfect eye function and perfect health. The utility value obtained was used to create a Markov model and run a cost-effectiveness analysis of blepharoplasty as a treatment for dermatochalasis while utilizing the societal perspective.

RESULTS

One hundred three patients with dermatochalasis recruited from an urban outpatient ophthalmology clinic completed the utility survey. The authors determined utility values for dermatochalasis ranging from 0.74 to 0.92 depending on the measurement method (standard reference gamble/time trade-off) and anchor points. The cost-effectiveness analysis yielded an incremental cost-effectiveness ratio of $3,146 per quality-adjusted life year, well under the conventional willingness-to-pay threshold of $50,000 per quality-adjusted life year. Probabilistic sensitivity analysis with Monte Carlo simulation demonstrated that blepharoplasty would be cost-effective in 88.1% of cases at this willingness-to-pay threshold.

CONCLUSIONS

Dermatochalasis has an impact on quality of life that is significantly associated with level of perceived functional impairment. Rising health care costs have underscored the importance of providing value-based treatment to patients, and the results of this study suggest that blepharoplasty is a cost-effective treatment option for symptomatic bilateral upper eyelid dermatochalasis.

Lymphocytic Esophagitis Presenting With Food Impaction

Lymphocytic esophagitis (LyE) is a rare diagnosis made on esophageal biopsy whose pathogenesis is poorly understood. Since its appearance in the literature 15 years ago, it still remains an enigma due to its low prevalence. In this case report, a 71-year-old male presented with an episode of acute dysphagia due to food impaction. Urgent endoscopy was performed to fragment the food bolus. Repeat endoscopy showed a stricture, and lymphocytic esophagitis was found on esophageal biopsy. A proton pump inhibitor (PPI) was initiated with symptomatic improvement. With its increasing prevalence, lymphocytic esophagitis should be on the differential for causes of dysphagia.

The overall quality of evidence of recommendations surrounding nutrition and diet in inflammatory bowel disease

BACKGROUND AND AIM

Recently, there has been an increased focus on the role nutrition and diet play in maintaining health in inflammatory bowel disease (IBD). We aimed to assess the overall quality, strength, and transparency of conflicts among guidelines on nutrition/diet in IBD.

METHODS

A systematic search was performed on multiple databases from inception until January 1, 2021, to identify guidelines pertaining to nutrition or diet in IBD. All guidelines were reviewed for disclosure of conflicts of interest (COI) and funding, recommendation quality and strength, external document review, patient representation, and plans for update-as per Institute of Medicine (IOM) standards. In addition, recommendations and their quality were compared between guidelines/societies.​ RESULTS: Seventeen distinct societies and a total of 228 recommendations were included. Not all guidelines provided recommendations on key aspects of diet-such as the role of supplements or the appropriate micro/macro nutrition in IBD. Fifty-nine percent of guidelines reported on COI, 24% underwent external review, and 41% included patient representation. 18.4%, 25.9%, and 55.7% of recommendations were based on high-, moderate-, and low-quality evidence, respectively. 10.5%, 24.6%, and 64.9% of recommendations were strong, weak/conditional, and did not provide a strength, respectively. The proportion of high-quality evidence (p = 0.12) and strong recommendations (p = 0.83) did not significantly differ across societies.

CONCLUSIONS

Many guidelines do not provide recommendations on key aspects of diet/nutrition in IBD. As over 50% of recommendations are based on low-quality evidence, further studies on nutrition/diet in IBD are warranted to improve the overall quality of evidence.

Current Applications of Telemedicine in Gastroenterology

Telemedicine generally refers to the use of technology to communicate with patients and provide health care from a distance. Advances in technology, specifically computers, cellphones, and other mobile devices, have facilitated healthcare providers' growing ability to virtually monitor and mentor patients. There has been a progressive expansion in the use of telemedicine in the field of gastroenterology (GI), which has been accelerated by the COVID-19 pandemic. In this review, we discuss telemedicine-its history, various forms, and limitations-and its current applications in GI. Specifically, we focus on telemedicine in GI practice in general and specific applications, including the management of inflammatory bowel disease, celiac disease, and colorectal cancer surveillance and its use as an aid in endoscopic procedures.

Pre-procedural Preparation and Sedation for Gastrointestinal Endoscopy in Patients with Advanced Liver Disease

Gastrointestinal endoscopy in patients with advanced liver disease poses various challenges, a major one being procedural sedation and its associated considerations. While sedation during endoscopy can improve patient comfort, decrease anxiety, and facilitate procedural completion, in patients with advanced liver disease, it is also associated with substantial and unique risks due to alterations in drug metabolism and other factors. As such, the choice of sedative agent(s) and related logistics may require careful inter-disciplinary planning and individualized considerations. Furthermore, a large proportion of agents require dose reductions and particular monitoring of the vital signs, level of consciousness, and other indices. In the present review, we provide a contemporary overview of procedural sedation considerations, commonly used intravenous sedatives, and second-line as well as novel sedatives for gastrointestinal endoscopy in patients with advanced liver disease.

Endoscopic Mucosal Resection: Best Practices for Gastrointestinal Endoscopists

Endoscopic mucosal resection (EMR) is an endoscopic technique used to remove sessile or flat lesions from the gastrointestinal tract. This article reviews EMR and focuses on large colorectal polyps, which constitute the most common indication for EMR. Various methods of polyp evaluation can help gastroenterologists determine whether EMR is feasible and whether referral to an advanced endoscopist may be necessary. Techniques for performing EMR include conventional hot-snare EMR with submucosal injection and electro-cautery snare removal of colorectal lesions, as well as alternative EMR techniques such as cold-snare EMR and underwater EMR. Key adverse events associated with EMR include bleeding, perforation, and post-polypectomy coagulation syndrome. Finally, as residual or recurrent polyp formation is possible regardless of EMR technique, this article addresses the importance of surveillance post-EMR and the patients who are at highest risk for polyp recurrence.

Innumerable pulmonary nodules

Early detection is critical with this aggressive disease. However, the patient's financial status prompted her to delay medical care.

Telemedicine in Hepatology: Current Applications and Future Directions

Telemedicine refers to the use of information and communication technologies for providing health care at a distance. Through the use of telecommunication technologies such as cell phones, computers, and other electronic devices, health care providers are able to conduct patient visits, mentor/train other providers, and monitor patients' chronic diseases remotely, potentially hundreds or thousands of miles away. Over the past 2 decades, the use of telemedicine has grown in the field of hepatology. In this review, we provide a focused primer on telemedicine and its current applications in hepatology. In particular, we discuss the use of telemedicine in the management of chronic hepatitis C, the complications of liver disease, as well as preliver transplantation evaluation and posttransplantation care. In addition, we provide a synopsis of the effect of the coronavirus disease 2019 (COVID-19) pandemic on the use of telemedicine in hepatology.

Large polyps: Pearls for the referring and receiving endoscopist

Polyps are precursors to colorectal cancer, the third most common cancer in the United States. Large polyps, i.e.,, those with a size ≥ 20 mm, are more likely to harbor cancer. Colonic polyps can be removed through various techniques, with the goal to completely resect and prevent colorectal cancer; however, the management of large polyps can be relatively complex and challenging. Such polyps are generally more difficult to remove en bloc with conventional methods, and depending on level of expertise, may consequently be resected piecemeal, leading to an increased rate of incomplete removal and thus polyp recurrence. To effectively manage large polyps, endoscopists should be able to: (1) Evaluate the polyp for characteristics which predict high difficulty of resection or incomplete removal; (2) Determine the optimal resection technique (e.g., snare polypectomy, endoscopic mucosal resection, endoscopic submucosal dissection, etc.); and (3) Recognize when to refer to colleagues with greater expertise. This review covers important considerations in this regard for referring and receiving endoscopists and methods to best manage large colonic polyps.

Global incidence, prevalence and features of primary sclerosing cholangitis: A systematic review and meta-analysis

BACKGROUND & AIMS

Primary sclerosing cholangitis (PSC) is an idiopathic, cholestatic liver disease with a diverse range of clinical manifestations. Inter-regional data on PSC are variable, but its global geoepidemiology has not been well-studied. We aimed to examine the worldwide incidence, prevalence and features of PSC and PSC-inflammatory bowel disease (PSC-IBD).

METHODS

A systematic search of multiple databases was conducted to identify all original, full-text studies until December 2020 with data regarding the incidence rate (IR) and/or prevalence of PSC. Outcomes were PSC IR, prevalence, features and IBD concurrence. Additionally, a meta-analysis of PSC IR was performed. The study was registered in PROSPERO (CRD42021224550).

RESULTS

Of the 1003 studies identified, 17 studies spanning three continents were included. PSC IR was 0.60 per 100 000 person-years (PY) (95% confidence interval: 0.37-0.88 per 100 000 PY). In pooled subgroup analysis for studies conducted in Europe and North America, PSC IR was 0.62 and 0.53 per 100 000 PY, respectively. PSC prevalence ranged 0-31.7 per 100 000 persons, with notable inter-regional differences. Mean age at PSC diagnosis was bimodally distributed, with relative peaks at 15 and 35 years. Mean concurrence of IBD with PSC was 50%, with 76% having ulcerative colitis, 17% Crohn's disease and 8% indeterminate/unspecified IBD.

CONCLUSION

While considerable heterogeneity exists in the geoepidemiology of PSC, overall, the classical dogmata of male predilection, bimodal distribution of mean age and high PSC-IBD concurrence appear to hold true. Despite a seemingly stable IR over time, further studies are needed to better understand the geoepidemiology of PSC.

Gastrointestinal Luminal Stenting: The Early US Experience with the Duodenal HANAROSTENT

Self-expandable metal stents (SEMSs) are frequently utilized for palliation of malignant gastric and/or duodenal outlet obstruction (GDOO). Re-establishing luminal patency with accurate SEMS positioning while limiting migration and adjacent tissue injury is an important technical consideration and aim. The duodenal HANAROSTENT^® was introduced in the USA in 2019 and developed with these challenges in mind. As the first center in the USA to deploy the duo-denal HANAROSTENT^® in clinical practice, we herein examine our early experience with its use. Specifically, we describe 7 consecutive cases of malignant GDOO in which a duodenal HANAROSTENT^® was placed for on-label use, defined as palliative treatment of malignant gastric and/or duodenal obstruction. All stents were 22 mm in diameter, with 5 being 90 mm and 2 being 120 mm in length. Technical and clinical success with duodenal HANAROSTENT^® placement were achieved in all 7 cases (100%). In no case was stent adjustment required post-deployment. There were no stent-related adverse events, and no subsequent endoscopic procedures were necessary in any of the patients during a mean follow-up of 5 months (range 1-12 months). In summary, the duodenal HANAROSTENT^® appears to perform well and be a promising alternative to other available duodenal SEMSs. As experience in the USA with this newly introduced duodenal SEMS grows, multicenter prospective data should be collected to better establish its relative safety and efficacy.

Difficult Biliary Cannulation in Endoscopic Retrograde Cholangiopancreatography: Definitions, Risk Factors, and Implications

Over the past 50 years, endoscopic retrograde cholangiopancreatography (ERCP) has become the preferred minimally invasive method of treating a vast array of pancreatobiliary diseases. An initial sine qua non for ERCP success is selective ductal cannulation. Despite significant progress in the optimisation of ERCP methods and accessories, selective biliary cannulation using conventional techniques remains unsuccessful in approximately 15% of native papilla cases. Furthermore, difficult biliary cannulation has been associated with an increased risk of post-ERCP pancreatitis, among other adverse events. Here, in the first of a two-part series, the authors provide a primer on standard biliary cannulation techniques and discuss the definition, risk factors, and implications of difficult biliary cannulation. The second part of the series will provide an overview of the existing advanced techniques used in cases of difficult biliary cannulation as well as the approach to their selection.

Difficult Biliary Cannulation in Endoscopic Retrograde Cholangiopancreatography: An Overview of Advanced Techniques

Endoscopic retrograde cholangiopancreatography (ERCP) plays a significant role in the treatment of a vast array of pancreatobiliary diseases. However, despite significant progress in the optimisation of ERCP methods and accessories, the technical and clinical success of ERCP can vary significantly due to a variety of patient and operator factors. Over the past several decades, a number of advanced techniques have been developed to improve cannulation success rates, including the use of double-guidewire, pancreatic duct accessory-assisted, precut, and rendezvous techniques. Here, the authors provide an update and overview of the existing advanced techniques used in cases of difficult biliary cannulation, as well as the approach to their selection.

Increased Mortality and Healthcare Costs Upon Hospital Readmissions of Ulcerative Colitis Flares: A Large Population-Based Cohort Study

Background

Ulcerative colitis (UC) flares often result in prolonged hospitalization and considerable mortality. Nevertheless, large-scale analyses evaluating the frequency and characteristics of hospital readmissions for UC remain limited. We aimed to examine these clinical outcomes in a nationwide cohort of patients hospitalized with UC.

Methods

We queried the 2017 Nationwide Readmission Database using ICD-10-CM codes to identify all adult patients admitted for UC. Outcomes including mortality, readmission rates, predictors of readmission and mortality, and healthcare usage were assessed. Multivariate analysis was used to adjust for potential confounders.

Results

From the 31,063 patients hospitalized for UC, 17.38% were readmitted within 30 days and 28.51% in 90 days. UC accounted for 28.17% and 29.82% of readmissions at 30 and 90 days, respectively. Compared to index admission, 30- and 90-day readmissions were characterized by significantly higher mortality (0.42% vs 1.99% and 1.65%, respectively), longer hospital stays (5.05 vs 6.62 and 6.04 days, respectively), and increased hospital cost ($49,999 vs $62,288 and $59,698, respectively) (all P < 0.01). Numerous factors, including chronic steroid use [hazard ratio (HR) 1.35] and opioid use (HR 1.6, were independently associated with increased 30-day readmission (P < 0.01). Numerous factors, including anxiety (HR 1.21) and venous thromboembolism (HR 5.39), were independently associated with increased 30-day mortality (P < 0.01).

Conclusions

In a large cohort of patients hospitalized for UC, we found that readmission is associated with higher mortality and more lengthy/costly admissions. Additionally, we found independent associations for readmission and mortality that may help identify patients who can benefit from close postdischarge follow-up.

Primary sclerosing cholangitis-associated cholangiocarcinoma: special considerations and best practices

Introduction: Primary sclerosing cholangitis (PSC) is a rare, heterogenous, chronic cholestatic liver disease that causes fibro-inflammatory destruction of the intra- and/or extrahepatic bile ducts. The disease course may be variable, though in many cases it ultimately leads to biliary cirrhosis and its associated complications. PSC is also associated with malignancies, in particular cholangiocarcinoma (CCA), a dreaded neoplasm of the biliary tract with a poor prognosis. Risk stratification and surveillance for this malignancy are important components of the care of patients with PSC.Areas covered: In this review, we discuss important considerations in the clinical epidemiology, risk factors, diagnosis, and surveillance of PSC-associated CCA.Expert opinion: Despite growing awareness of PSC, high-quality evidence regarding the management of PSC and its associated risk of CCA remains limited. Early diagnosis of PSC-associated CCA remains difficult, and treatment options are limited, especially when diagnosed at later stages. The recent introduction of recommendations for CCA surveillance will likely improve outcomes, though an optimal surveillance approach has yet to be validated prospectively. Further research is needed in the development of high-accuracy (and noninvasive) surveillance and diagnostic tools that may facilitate earlier diagnosis of CCA and potential disease cure.

Rates of inflammatory bowel disease in Hispanics comparable to non-Hispanic Whites: results of a cohort study

PURPOSE

Previous studies have suggested that inflammatory bowel disease (IBD) occurs at higher rates among non-Hispanic Whites (NHWs) compared to other ethnicities; however, Hispanics as the largest minority in the United States remain underrepresented in IBD research and we hypothesize that they have similar rates of IBD. We examined the epidemiology, demographics, clinical presentation, and treatment of IBD in a predominantly Hispanic cohort in Los Angeles (LA) County.

METHODS

This was a retrospective cohort study based at Olive View-UCLA Medical Center, one of the three major safety-net hospitals in LA County. Electronic medical records from 2015 to 2018 were queried, and biopsy-proven cases of IBD (n = 170) were identified. Outcomes included the incidence and prevalence of IBD, disease distribution, treatment, and IBD-related surgery.

RESULTS

The incidence of IBD among Hispanics was 175 (95% confidence interval [CI] 127-240) and 113 (95% CI 62-200) for NHWs per 100,000 person-years. Prevalence of IBD per 100,000 people was 418 (95% CI 341-512) for Hispanics and 557 (95% CI 431-739) for NHWs. Notably, the proportion of Hispanic IBD patients with a history of smoking was 21.5% vs 50.8% in NHWs (p = 0.011). There were no significant differences between the two groups with regard to Montreal classification, pharmacotherapy, or IBD-related surgery.

CONCLUSIONS

In one of the largest US studies of Hispanics with IBD, and the only one to have both clinical and histopathologic confirmation as inclusion criteria, we found the incidence and prevalence of IBD among Hispanics to be higher than previously recognized and comparable to NHWs. Additionally, Hispanic IBD patients had lower rates of smoking compared to NHWs.

Signet Ring Cell Gastric Carcinoma: Clinical Epidemiology and Outcomes in a Predominantly Latino County Hospital Population

BACKGROUND

Gastric signet ring cell carcinoma (GSRC) is a rare but increasingly prevalent tumor histotype whose clinical features and natural history are poorly understood, particularly in the USA and minorities.

AIMS

To examine the occurrence, clinico-demographic characteristics, oncologic features, treatment, and outcomes of GSRC in a predominantly minority county hospital setting and benchmark them against data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program.

METHODS

We queried biopsy-proven GSRC cases at a Los Angeles County hospital, from 2004 to 2017. Clinical characteristics, treatment, and survival data were collected and compared to SEER data.

RESULTS

We identified 63 patients with GSRC. Compared to SEER, our cohort was significantly younger (52.6 vs. 63.5 years, p < 0.01), Hispanic/Latino predominant (81% vs. 20%, p < 0.01), had higher overall stage (86% vs. 69% with stage III/IV, p < 0.01), and more frequent node involvement (89% vs. 49%, p < 0.01). Lower tumor stage, Helicobacter pylori positivity, and surgical intervention were associated with significantly longer median survival (all p < 0.05), which was similar in our study compared to SEER (median 12.6 vs. 9.0 months, p = 0.26).

CONCLUSIONS

Patients with GSRC within the Los Angeles County population have different clinical characteristics compared to what has been reported in SEER. Our cohort was younger, and despite having more advanced disease, did not have shorter survival. Further study is needed to better identify protective and risk factors in this population and improve understanding of the etiopathogenesis and natural history of this malignancy.

Association between chronic inflammatory demyelinating polyneuropathy and gastrointestinal malignancies

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an uncommon and under-recognized immune-mediated disorder of the peripheral nervous system. It is associated with both infectious and non-infectious etiologies and presents in several variant forms. In rare instances, CIDP has been reported in association with gastrointestinal (esophageal, hepatic, colorectal, and pancreatic) malignancies. The diagnosis of malignancy is typically preceded by weeks to months by that of CIDP, though the inverse may also be seen. As with other etiologies of CIDP, cases associated with gastrointestinal malignancies are often treated with corticosteroids, intravenous immunoglobulins, and/or plasma exchange, with improvement or resolution of neurological symptoms in the majority of cases. In this review, we provide a practical overview of CIDP, with an emphasis on recognizing the clinical association between CIDP and gastrointestinal malignancies.

Clear cap-assisted luminal stenting may improve technical success in gastroduodenal and colonic obstruction

Background  Luminal stenting is safe, effective, and at times the preferred method for relieving gastrointestinal obstruction. However, stent placement is not technically feasible when lesions cannot be traversed with a guidewire, resulting in the need for more invasive methods of palliation and urgent/emergent surgical intervention. In this series, we report our experience with cap-assisted stenting to improve lumen visualization in obstructed segments of the gastrointestinal tract and salvage cases that may have otherwise resulted in technical failure. Methods  A clear cap (i. e. distal attachment) was affixed to the scope tip to facilitate visualization and stenting in two cases of gastroduodenal obstruction and three cases of colonic obstruction. Indications for stent placement included malignant obstruction, diverticulitis-associated obstruction, and Crohn's disease-associated stricture. Results  In this report, we demonstrate that use of a clear cap facilitated endoscopic stenting in challenging cases of malignant and benign gastroduodenal and colonic obstruction. Conclusions  A clear cap for endoscopic stenting can be used in cases in which standard techniques are unsuccessful or those anticipated to be technically difficult at the outset. Cases with tortuous anatomy or particularly tight, friable, or exophytic obstructive lesions may benefit most from this novel technical modification.

Endoscopic ultrasound in chronic liver disease

Endoscopic ultrasound (EUS) is a minimally invasive diagnostic and therapeutic modality with a number of established as well as evolving uses in patients with chronic liver disease. Compared to other diagnostic tools such as cross-sectional imaging or conventional endoscopy, EUS has been shown to increase diagnostic sensitivity and therapeutic success for many clinical scenarios and applications with a low rate of adverse events. In this review, we discuss and focus on the current and growing role of EUS in the evaluation and/or treatment of hepatobiliary masses, hepatic parenchymal disease, portal hypertension, esophageal and other varices, and indeterminate biliary strictures.

Cholangioscopy and its Role in Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a cholestatic liver disease characterised by chronic inflammation and fibro-obliteration of the intrahepatic and/or extrahepatic bile ducts. It is associated with numerous hepatobiliary complications including an increased risk of malignancy (in particular, cholangiocarcinoma) and biliary tract stone formation. The evaluation of biliary strictures in patients with PSC is especially challenging, with imaging and endoscopic methods having only modest sensitivity for the diagnosis of cholangiocarcinoma, and treatment of biliary strictures poses a similarly significant clinical challenge. In recent years, peroral cholangioscopy has evolved technologically and increased in popularity as an endoscopic tool that can provide direct intraductal visualisation and facilitate therapeutic manipulation of the biliary tract. However, the indications for and effectiveness of its use in patients with PSC remain uncertain, with only a few studies performed on this small but important subset of patients. In this review, the authors discuss the available data regarding the use of peroral cholangioscopy in patients with PSC, with a focus on its use in the evaluation and management of biliary strictures and stones.

Geoepidemiologic variation in outcomes of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic, progressive, hepatobiliary disease characterized by inflammation and fibrosis of the intra- and extra-hepatic bile ducts. Its natural history is one that generally progresses towards cirrhosis, liver failure, cholangiocarcinoma, and ultimately disease-related death, with a median liver transplantation-free survival time of approximately 15-20 years. However, despite its lethal nature, PSC remains a heterogenous disease with significant variability in outcomes amongst different regions of the world. There are also many regions where the outcomes of PSC have not been studied, limiting the overall understanding of this disease worldwide. In this review, we present the geoepidemiologic variations in outcomes of PSC, with a focus on survival pre- and post-liver transplantation as well as the concurrence of inflammatory bowel disease and hepatobiliary neoplasia.

Biliary endoscopy in the management of primary sclerosing cholangitis and its complications

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic, cholestatic liver disease characterized by inflammation and fibrosis of the intrahepatic and/or extrahepatic bile ducts. It can affect individuals of all age groups and gender, has no established pharmacotherapy, and is associated with a variety of neoplastic (e.g. cholangiocarcinoma) and non-neoplastic (e.g. dominant strictures) hepatobiliary complications. Given these considerations, endoscopy plays a major role in the care of patients with PSC. In this review, we discuss and provide updates regarding endoscopic considerations in the management of hepatobiliary manifestations and complications of PSC. Where evidence is limited, we suggest pragmatic approaches based on currently available data and expert opinion.

Foreign object ingestion and esophageal food impaction: An update and review on endoscopic management

Foreign body ingestion encompasses both foreign object ingestion (FOI) and esophageal food impaction (EFI) and represents a common and clinically significant scenario among patients of all ages. The immediate risk to the patient ranges from negligible to life-threatening, depending on the ingested substance, its location, patient fitness, and time to appropriate therapy. This article reviews the FOI and EFI literature and highlights important considerations and implications for pediatric and adult patients as well as their providers. Where published literature is insufficient to provide evidence-based guidance, expert opinion is included to supplement the content of this comprehensive review.

Cancer risk in primary sclerosing cholangitis: Epidemiology, prevention, and surveillance strategies

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by progressive fibroinflammatory destruction of the intra- and/or extrahepatic biliary ducts. While its features and disease course can be variable, most patients with PSC have concurrent inflammatory bowel disease and will eventually develop liver cirrhosis and end-stage liver disease, with liver transplantation representing the only potentially curative option. Importantly, PSC is associated with a significantly increased risk of malignancy compared to the general population, mainly cholangiocarcinoma, gallbladder carcinoma, hepatocellular carcinoma, and colorectal cancer, with nearly 50% of deaths in patients with PSC being due to cancer. Therefore, robust surveillance strategies are needed, though uncertainty remains regarding how to best do so. In this review, we discuss the epidemiology, prevention, and surveillance of cancers in patients with PSC. Where evidence is limited, we present pragmatic approaches based on currently available data and expert opinion.

The presence of long-lived spin states in organic solids with rapid molecular motions

For organic solids with sufficiently mobile molecular segments, the application of a long and weak pulse (gammaB1/2pi approximately Hz) can yield inverted sharp peaks with linewidths of approximately 100 Hz in the 1H NMR spectra, and the use of multi-frequency weak pulses can excite multiple inverted sharp peaks. For these compounds, the normal 1H free induction decay (FID) of a static sample contains a slowly decaying part, which can be detected by acquisition delay up to about 2 ms. The presence of highly mobile molecular segments can also be identified by using a "dipolar filter."

Selective excitation in spin systems with homogeneous broadening

We have found that the application of a weak radio frequency (rf) pulse to a spin system with indirect spin-spin (J) couplings can produce a narrow inverted peak in spectral regions where there are many overlapping peaks. Examples of three compounds with (1)H-(1)H J couplings and one with (1)H-(13)C J couplings are given. The dependences of the signals on the frequency, duration, and amplitude of the weak rf irradiation have been studied. For an rf power of gammaB(1)/2pi=1.0 Hz, pulse widths longer than 0.25 s consistently produce inverted narrow peaks in spectral regions with unresolved peaks. An interpretation of the origin of this unusual result of selective excitation in spin systems with homogeneous broadening is given: the inverted signal observed can be considered as a cumulative effect of the weak rf irradiation acting on many uncorrelated transitions that are slightly off resonance on both sides of the irradiating frequency; the only role of the J couplings (or dipolar couplings in liquid crystals) is to produce a large number of closely spaced peaks that overlap with each other. Computer simulations of both coupled and noninteracting spin systems have been carried out, and the results support this interpretation.

A simple method for NMR photography

The application of a multi-frequency weak pulse to a liquid crystal can excite narrow 1H NMR peaks at the applied frequencies. By using two-level amplitude coding, namely setting the amplitudes of some of the harmonics to zero, this method can be used to store up to 1024 bits of binary information in the liquid crystal molecules. When the information is retrieved in the form of a spectrum, which is plotted as an array of 32 or 16 segments, the stack of spectral segments reproduces a 2D input pattern quite well. This technique is called "NMR photography." The original method was a pseudo-2D technique that applies the 1024-frequency pulse in the first step, and reads the signal row-by-row in the second step. The present improvement involves subtracting two spectra obtained with the same 1024-frequency pulse but with different durations, so that the method becomes a 1D technique, with a tremendous saving of experimental time. Several examples are given to illustrate the results.

A simple method for the preparation of pseudopure states in nuclear magnetic resonance quantum information processing

The use of nuclear magnetic resonance (NMR) to carry out quantum information processing (QIP) often requires the preparation, transformation, and detection of pseudopure states. In our previous work, it was shown that the use of pairs of pseudopure states (POPS) as a basis for QIP is very convenient because of the simplicity in experimental execution. It is now further demonstrated that the product of the NMR spectra corresponding to two sets of POPS that share a common pseudopure state has the same peak frequencies as those of the common (single) pseudopure state. Examples of applying two different quantum logic gates to a 5-qubit system are given.

NMR implementation of a parallel search algorithm

Recently it has been shown that the dynamics of a cluster of dipolar-coupled spins can be manipulated to store and process a large amount of information in a parallel way [Chem. Phys. Lett. 360, 161 (2002)]]. Here it is further demonstrated that it is possible to realize a cascade of parallel bitwise operations on a spin cluster so that an algorithm of parallel search can be experimentally implemented by means of nuclear magnetic resonance.

Phospholipid Bicelles That Align with Their Normals Parallel to the Magnetic Field

We have recently reported phospholipid bicelles (bilayered micelles) that have positive anisotropy of the magnetic susceptibility and align with their normals parallel to an external magnetic field [J. Am. Chem. Soc. 2001, 123, 1537]. Improvements have been made via the synthesis of a new phospholipid, 1-dodecanoyl-2-(4-(4-biphenyl)butanoyl)-sn-glycero-3-phosphocholine (DBBPC). Bicelles can be formed by mixing DBBPC with a short-chain phospholipid, 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) in a ratio between 5.1:1 and 6.5:1 in an aqueous medium. The (31)P NMR spectra clearly show that these bicelles align with their principal axes parallel to the magnetic field within a wide temperature range. The (31)P chemical shifts indicate that the conformation of the polar headgroup in these bicelles may be different from that in common bicelles. The phase behavior of a mixture of DBBPC/DHPC with 6:1 mole ratio was investigated in the temperature range of 10-75 degrees C using (31)P, (2)H, and (23)Na NMR. At lower temperatures (10-54 degrees C), the system is dominated by the bicellar phase. At higher temperatures (54-75 degrees C), isotropic micelles are formed and coexist with the bicelles. The partial alignment of maltotriose in the DBBPC/DHPC system was studied at three temperatures, and the (1)H-(13)C dipolar coupling constants are compared with those obtained for two other bicelle solutions.

14N chemical shifts and quadrupole coupling constants of inorganic nitrates

The isotropic chemical shift and the nuclear quadrupole coupling constant for (14)N were obtained for 14 inorganic nitrates by solid-state MAS NMR measurements at two different field strengths, 9.4 and 11.7 T. The compounds studied were polycrystalline powders of AgNO(3), Al(NO(3))(3), Ba(NO(3))(2), Ca(NO(3))(2), CsNO(3), KNO(3), LiNO(3), Mg(NO(3))(2), NaNO(3), Pb(NO(3))(2), RbNO(3), Sr(NO(3))(2), Th(NO(3))(4)center dot4H(2)O, and UO(2)(NO(3))(2)center dot3H(2)O. Even though the spectra show broadening due to (14)N quadrupole interactions, linewidths of a few hundred hertz and a good signal-to-noise ratio were achieved. From the position of the central peaks at the two fields, the chemical shifts and the nuclear quadrupole coupling constants were calculated. The chemical shifts for all compounds studied range from 282 to 342 ppm with respect to NH(4)Cl. The nuclear quadrupole coupling constants range from 429 kHz for AgNO(3) to 993 kHz for LiNO(3). These data are compared with those available in the literature.

Indirect NMR detection in solids with multiple cross-polarization periods

The use of indirect detection for signal enhancement in solids is much less common than in liquids, but has attracted renewed interest recently. In this work we describe an indirect detection scheme that offers a large signal enhancement for rare spins in solids. The method uses multiple periods of cross polarization, each followed by an evolution period. The latter is increased stepwise in a pseudo 2D experiment, in which the signal of the rare spin is detected as modulation of the abundant spin. As an illustration of this method, the natural abundance deuterium NMR spectrum of a static powder sample of 1,2,4,5-tetramethylbenzene is presented.

Filtering of spinning sidebands in 1D MAS NMR spectra

Spinning sidebands (SSBs) in the MAS NMR spectrum of a polycrystalline solid are related to the principal values of the chemical shift or quadrupole coupling tensors. At present, 2D methods are widely used to sort out the SSBs for each isotropic peak. Here a simple and efficient method for separating the SSBs in 1D MAS NMR spectra is described. It is based on finding the optimal spinning rate with a mathematical algorithm and subsequently treating the spectra with filtering functions.

An improved broadband decoupling sequence for liquid crystals and solids

Recently we developed an efficient broadband decoupling sequence called SPARC-16 for liquid crystals ¿J. Magn. Reson. 130, 317 (1998). The sequence is based upon a 16-step phase cycling of the 2-step TPPM decoupling method for solids ¿J. Chem. Phys. 103, 6951 (1995). Since then, we have found that a stepwise variation of the phase angle in the TPPM sequence offers even better results. The application of this new method to a liquid crystalline compound, 4-n-pentyl-4'-cyanobiphenyl, and a solid, L-tyrosine hydrochloride, is reported. The reason for the improvement is explained by an analysis of the problem in the rotating frame.

13C NMR of liquid crystals with different proton homonuclear dipolar decoupling methods

The effect of several new homonuclear dipolar decoupling methods (frequency-switching Lee-Goldburg decoupling and two sequences based on z-rotational decoupling) on the 13C spectra of liquid crystals has been studied, and the results are compared with those obtained by using two well-established methods (MREV-8 and BLEW-48). For benzene dissolved in two liquid crystalline solvents, BLEW-48 gives the best spectral resolution. The BLEW-48 sequence has also been applied to the 2D method of proton-encoded local field (PELF) spectroscopy to study a bulk liquid crystal, 4-n-pentyl-4'-cyanobiphenyl (5CB). The results are compared with those obtained by using MREV-8, and it is suggested that the BLEW-48 sequence may be preferable to MREV-8 for application in the PELF method. Copyright 1999 Academic Press.

An efficient broadband decoupling sequence for liquid crystals

A new and efficient broadband decoupling sequence is presented. It is based on the phase cycling of two pulses with small phase angles. The pulse width is 180 degrees +/- 30 degrees, and the phase angle is +/-10 degrees-12 degrees. The sequence contains 16 elements, and is called SPARC-16 as an abbreviation for small phase angle rapid cycling. The application of this sequence to a liquid crystalline compound, 4-n-pentyl-4'-cyanobiphenyl (5CB), is reported. The signal-to-noise ratios and the linewidths of the 13C peaks of 5CB with SPARC-16 decoupling and with other decoupling methods are compared. The results show that the broadband decoupling efficiency of SPARC-16 is considerably better than those of other methods.

A Study of the Adsorption of Acrylic Acid and Maleic Acid from Aqueous Solutions onto Alumina

The adsorption of acrylic acid and maleic acid on alumina was studied, and it has been found that the adsorption obeys the Langmuir isotherm. The adsorption of the acids is dependent on the pH of the solutions. For acrylic acid, the optimal pH is 4.5; for maleic acid, the optimal pH is 1.1-1.6. These pH values are close to the pKa for acrylic acid and pKa 1 for maleic acid, respectively. The maximum amount of each acid adsorbed at its optimal pH was obtained by fitting the adsorption data to the Langmuir isotherm, and the values are 727 &mgr;mol/g for acrylic acid and 525 &mgr;mol/g for maleic acid. These values are consistent with monolayer adsorption. Solid state 13 C NMR was used to investigate the nature of the adsorption. It is suggested that the adsorbed carboxylic acids are present in the undissociated form.

Line Narrowing in Solid-State Proton NMR with Acquisition Delay

Organic solids have extensive proton-proton dipolar interactions, and their 1H NMR linewidths are very large even with magic-angle spinning at moderate speeds. Recently it has been shown that substantial narrowing of the proton linewidths of organic solids can be achieved by using single-pulse excitation with acquisition delay or spin echo [S. Ding and C. A. McDowell, J. Magn. Reson. A 111, 212 (1994); 115, 141 (1995); 117, 171 (1995)]. This interesting line-narrowing phenomenon has been further examined through the study of several amino acids, their deuterated analogs, and some aromatic compounds. The results confirm that narrow proton peaks are observed with long acquisition delay, and the peaks appear in the appropriate chemical-shift ranges for organic protons (0-10 ppm with respect to tetramethylsilane). However, except for some special cases, the observed peaks cannot be assigned to individual types of protons based on chemical-shift considerations only. To explore the reason for the line narrowing, the effect of acquisition delay on the 19F linewidth of CaF2 was also studied and compared with that on the 1H linewidths of organic solids. It is suggested that the broad proton peak in an organic solid is a superposition of numerous transitions. These transitions have different linewidths, and the narrow peaks in the spectrum remain observable with long acquisition delays.

Thrombolysis using liposomal-encapsulated streptokinase: an in vitro study

The clot-lysing ability of streptokinase (SK) was examined using membrane-bound thrombi. Encapsulation of SK in large unilamellar phospholipid vesicles (liposomes) resulted in entrapping approximately 30% of its original activity. Measurements of streptokinase activity for liposomal-encapsulated streptokinase (LESK) indicated little loss of activity or leakage in Tris-buffered saline over a 24-hr period at temperatures of 4 and 23 degrees C. However, incubation of free SK and LESK in platelet-poor plasma (PPP) at 37 degrees C resulted in a decrease of SK activity. The retention of SK activity in LESK was considerably higher than that of unentrapped SK. Clot-dissolving time (CDT) was measured by monitoring the pressure drop during slow filtration in plasma through membrane-bound thrombi. The results indicated that both LESK and free SK were able to activate the fibrinolytic system. Without prior incubation in PPP at 37 degrees C, the CDT of a SK and PPP mixture (SK/PPP) was 10.7 +/- 1.9 min (n = 12), while that of a LESK and PPP mixture (LESK/PPP) was 12.4 +/- 1.7 min (n = 12). The CDT-detected clot-lysing abilities of both SK and LESK were diminished by incubation in PPP, but to different extents. After 15- and 30-min incubations, the CDT of SK/PPP increased significantly to 15.5 +/- 1.5 and 24.1 +/- 2.4 min (n = 5, P less than 0.05), respectively. In contrast, the CDT of LESK/PPP increased to 13.3 +/- 0.8 min (n = 5) after 15 min of incubation and to 16.0 +/- 1.1 min (n = 5, P less than 0.05) after a 30-min incubation. These results suggest that entrapment of SK in liposomes preserves the thrombolytic potential of the plasminogen activator by limiting its exposure to the components of the plasma.

Dynamic evaluation of clotting phenomena in vitro and perfluorochemical oxygen transport across a membrane-bound thrombus model

Citrated platelet-rich plasma was used to occlude 3-microns and 10-microns poresize Nuclepore membranes after recalcification as a thrombus model. Morphologic studies, using both light microscopy and scanning electron microscopy, indicated that over 90 percent of the number of pores available for filtration in hydrophilic and hydrophobic membranes were occluded either partially or completely. Results of transient and steady state pressure drop measurements supported the morphologic studies. It was found that the percentage of oxygen transported across the occluded membranes was greater for filtration of red blood cell suspensions diluted with a perfluorochemical emulsion than that of those diluted with Ringers. The findings in this study suggested that perfluorochemical emulsions might transport oxygen across a thrombus to maintain tissue viability during acute ischemic events.