Frequency of abnormal pancreatic and biliary sphincter manometry compared with clinical suspicion of sphincter of Oddi dysfunction

BACKGROUND

Sphincter of Oddi manometry as performed at ERCP is the most accepted method to evaluate for sphincter of Oddi dysfunction. To fully assess for sphincter of Oddi dysfunction, both the pancreatic and the bile ducts must be evaluated. We assessed the frequency of pancreatic and biliary sphincter abnormalities in a large series of patients.

METHODS

A total of 593 patients underwent manometry of the biliary and pancreatic ducts at one endoscopic retrograde cholangiopancreatography session. Basal sphincter pressure greater than or equal to 40 mm Hg was considered abnormal. Phasic waves were not evaluated. Manometric abnormalities were correlated with the clinical presentation as categorized using a modified Geenen/Hogan classification.

RESULTS

Of 360 patients with intact sphincters, 18.9% had abnormal pancreatic sphincter basal pressure alone, 11.4% had abnormal biliary basal sphincter pressure alone, and in 31.4% the basal pressure was abnormal for both sphincters; thus, 60.1% of the patients had sphincter dysfunction. The frequency of sphincter of Oddi dysfunction did not differ whether typed by biliary or pancreatic criteria: approximately 65% type II and 59% type III. Of patients without pancreatitis, 55.9% had an abnormal basal sphincter pressure, whereas sphincter dysfunction was present in 72.3% of those with idiopathic pancreatitis and 53.9% of patients with chronic pancreatitis. Of patients with an ablated biliary sphincter, 45.9% had abnormal basal pancreatic sphincter pressure and only 0.6% had an abnormal biliary sphincter pressure alone. Abnormal pressure in both sphincters was found in 9.3%.

CONCLUSION

If both portions of the sphincter of Oddi are studied simultaneously, abnormalities are found very commonly (55% to 72%). Assessment of both sides of the sphincter is necessary. Classifying patients according to both pancreatic and biliary sphincter segments is cumbersome, and may be replaced by an overall type. Using this modified classification, the frequency of sphincter of Oddi dysfunction is similar in both type II and type III patients (59% to 67%).

Endoscopic therapy in anomalous pancreatobiliary duct junction

BACKGROUND

Anomalous pancreaticobiliary duct junction is associated with bile duct strictures, pancreatitis, choledochal cysts, and biliary carcinoma. Limited data are available for outcomes of endoscopic therapy.

METHODS

Review of 7537 patients undergoing endoscopic retrograde cholangiopancreatography from 1988 to 1997 yielded 18 patients with anomalous pancreaticobiliary duct junction. Therapeutic responses were tallied by chart review and phone calls.

RESULTS

There were 13 women and 5 men, with a mean age of 36 years. Twelve patients had no ductographic evidence of pancreatitis and 6 had chronic pancreatitis. Seven had choledochal cysts. Fifteen patients (83%) underwent endoscopic biliary sphincterotomy, two of whom underwent repeat endoscopic biliary sphincterotomy for recurrence of symptoms. The other therapies included stent placement for benign biliary strictures in 5 patients, lithotripsy of pancreatic stones in 1 patient, and choledochal cyst removal in 4 patients. Three cases with malignant biliary strictures are excluded from endoscopic outcome studies. The 12 patients with pancreatitis had a mean of 2.0 episodes per year before any treatment. After endoscopic therapy 7 patients had no further episodes of pancreatitis, whereas 5 patients had further episodes, with a mean of one additional attack per year, over 3 years mean follow-up.

CONCLUSIONS

Patients with anomalous pancreaticobiliary duct junction have complex pathology associated with strictures, choledochal cysts, pancreatitis, and malignancies. Endoscopic therapy appeared to benefit 13 of 15 patients without malignant disease with elimination of or decreased frequency of pancreatitis. Endoscopic therapy appears to be a logical first step in the management of most symptomatic patients with anomalous pancreaticobiliary duct junction.

The DRD2 TaqI polymorphism and symptoms of attention deficit hyperactivity disorder

The relationship of the DRD2 TaqI-A1 allele to hyperactive/impulsive and inattentive symptoms of attention deficit hyperactivity disorder (ADHD) in children and adolescents was examined in a sample of clinic-referred children and their siblings, and control children and their siblings (n = 236). The contribution of genetic dominance and additivity to mean differences among the A2A2, A1A2, and A1A1 genotypes was estimated using structural equation modeling. The effect of genetic additivity was statistically significant for both traits in an analysis of all children. The heritability from the DRD2 locus was estimated at 4.27% for hyperactive-impulsive symptoms and 2.12% for inattentive symptoms. Children with the A2A2 genotype had the highest mean level of symptoms. To control for any possible effects of population stratification, this analysis was repeated with parental genotypes as controls. In this smaller sample, although the direction of the effect was the same as that in the whole sample, the genotypic differences failed to reach conventional significance levels and the effect sizes were smaller (h2 = 1.62% and 0.79%, respectively). Furthermore, a genotype relative risk test of children who had questionnaire-based diagnoses of ADHD also failed to yield evidence of either association or linkage. Given that the A1 allele was expected to be the high risk allele, and that results were non-significant in tests that controlled for population heterogeneity, we doubt that this DRD2 polymorphism influences symptoms of ADHD in childhood.

Classification and management of perforations complicating endoscopic sphincterotomy

BACKGROUND

The management of perforations after endoscopic sphincterotomy (ES) is controversial. The purpose of this study was to analyze the treatments and outcome of patients with ES perforations.

METHODS

Between January 1994 and July 1998, in a series of 6040 endoscopic retrograde cholangiopancreatographies, 2874 (48%) ESs were performed: 40 patients (0.6%) with perforation were identified and retrospectively reviewed.

RESULTS

All patients (n = 14) with guidewire perforation (group I) were recognized early, managed medically, and discharged after a mean hospital stay of 3.5 days. Twenty of 22 patients with periampullary perforation (group II) were identified early; 18 patients (90%) had aggressive endoscopic drainage, and none required operation. Of the 2 patients identified late, 1 patient required operation and subsequently died. Mean hospital stay for this group was 8.5 days. Only 1 of 4 patients with duodenal perforations (group III) was identified early; all required operation; 1 patient died, and the mean hospital stay was 19.5 days.

CONCLUSIONS

ES perforation has 3 distinct types: guidewire, periampullary, and duodenal. Guidewire perforations are recognized early and resolve with medical treatment. Periampullary perforations diagnosed early respond to aggressive endoscopic drainage and medical treatment. Postsphincterotomy perforations diagnosed late (particularly duodenal) require surgical drainage, which carries a high morbidity and mortality rate.

Classification and management of perforations complicating endoscopic sphincterotomy

BACKGROUND

The management of perforations after endoscopic sphincterotomy (ES) is controversial. The purpose of this study was to analyze the treatments and outcome of patients with ES perforations.

METHODS

Between January 1994 and July 1998, in a series of 6040 endoscopic retrograde cholangiopancreatographies, 2874 (48%) ESs were performed: 40 patients (0.6%) with perforation were identified and retrospectively reviewed.

RESULTS

All patients (n = 14) with guidewire perforation (group I) were recognized early, managed medically, and discharged after a mean hospital stay of 3.5 days. Twenty of 22 patients with periampullary perforation (group II) were identified early; 18 patients (90%) had aggressive endoscopic drainage, and none required operation. Of the 2 patients identified late, 1 patient required operation and subsequently died. Mean hospital stay for this group was 8.5 days. Only 1 of 4 patients with duodenal perforations (group III) was identified early; all required operation; 1 patient died, and the mean hospital stay was 19.5 days.

CONCLUSIONS

ES perforation has 3 distinct types: guidewire, periampullary, and duodenal. Guidewire perforations are recognized early and resolve with medical treatment. Periampullary perforations diagnosed early respond to aggressive endoscopic drainage and medical treatment. Postsphincterotomy perforations diagnosed late (particularly duodenal) require surgical drainage, which carries a high morbidity and mortality rate.

Collagen fibres in the wall of odontogenic keratocysts: a study with picrosirius red and polarizing microscopy

The collagen in the walls of 15 keratocysts was studied histochemically by staining sections with picrosirius red and examining them with polarizing microscopy. This was compared to 15 cases of dentigerous cyst and 15 cases of radicular cyst. Polarization colours of the collagen fibres were recorded according to their width. No differences were found between the polarization colours of thin fibres (<0.8 microm) in all three lesions; the polarization colours of thick fibres (1.6-2.4 microm) in keratocysts were significantly more greenish-yellow when compared with those of dentigerous cysts and radicular cysts. The staining of the collagen fibres in the keratocysts is similar to that reported in odontogenic neoplasms, which suggests that the stroma of keratocysts could be regarded not just as a structural support of the cyst wall, but as playing a part in the neoplastic behaviour of the cyst.

Pancreatitis and cystic fibrosis gene mutations

Cystic fibrosis (CF) is a genetic disease with multisystem involvement in which defective chloride transport across membranes causes dehydrated secretions. The protein encoded by the CF gene--the cystic fibrosis transmembrane conductance regulator (CFTR)--functions as a cyclic adenosine monophosphate-regulated chloride channel. The ability to detect CFTR mutations has led to the recognition of its association with a variety of conditions, including chronic bronchitis, sinusitis with nasal polyps, pancreatitis, and, in men, infertility. This article reviews the impact of CF on the pancreas, the role of the CFTR protein in pancreatic secretion, and some of the exciting research identifying mutations in the CFTR gene as a risk factor for idiopathic acute and chronic pancreatitis.

Functional disorders of the biliary tract and pancreas

The term "dysfunction" defines the motor disorders of the gall bladder and the sphincter of Oddi (SO) without note of the potential etiologic factors for the difficulty to differentiate purely functional alterations from subtle structural changes. Dysfunction of the gall bladder and/or SO produces similar patterns of biliopancreatic pain and SO dysfunction may occur in the presence of the gall bladder. The symptom-based diagnostic criteria of gall bladder and SO dysfunction are episodes of severe steady pain located in the epigastrium and right upper abdominal quadrant which last at least 30 minutes. Gall bladder and SO dysfunctions can cause significant clinical symptoms but do not explain many instances of biliopancreatic type of pain. The syndrome of functional abdominal pain should be differentiated from gall bladder and SO dysfunction. In the diagnostic workup, invasive investigations should be performed only in the presence of compelling clinical evidence and after non-invasive testing has yielded negative findings. Gall bladder dysfunction is suspected when laboratory, ultrasonographic, and microscopic bile examination have excluded the presence of gallstones and other structural abnormalities. The finding of decreased gall bladder emptying at cholecystokinin-cholescintigraphy is the only objective characteristic of gall bladder dysfunction. Symptomatic manifestation of SO dysfunction may be accompanied by features of biliary obstruction (biliary-type SO dysfunction) or significant elevation of pancreatic enzymes and pancreatitis (pancreatic-type SO dysfunction). Biliary-type SO dysfunction occurs more frequently in postcholecystectomy patients who are categorized into three types. Types I and II, but not type III, have biochemical and cholangiographic features of biliary obstruction. Pancreatic-type SO dysfunction is less well classified into types. When non-invasive investigations and endoscopic retrograde cholangiopanreatography show no structural abnormality, manometry of both biliary and pancreatic sphincter may be considered.

In vitro expansion of a multipotent population of human neural progenitor cells

The isolation and expansion of human neural progenitor cells have important potential clinical applications, because these cells may be used as graft material in cell therapies to regenerate tissue and/or function in patients with central nervous system (CNS) disorders. This paper describes a continuously dividing multipotent population of progenitor cells in the human embryonic forebrain that can be propagated in vitro. These cells can be maintained and expanded using a serum-free defined medium containing basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF), and epidermal growth factor (EGF). Using these three factors, the cell cultures expand and remain multipotent for at least 1 year in vitro. This period of expansion results in a 10(7)-fold increase of this heterogeneous population of cells. Upon differentiation, they form neurons, astrocytes, and oligodendrocytes, the three main phenotypes in the CNS. Moreover, GABA-immunoreactive and tyrosine hydroxylase-immunoreactive neurons can be identified. These results demonstrate the feasibility of long-term in vitro expansion of human neural progenitor cells. The advantages of such a population of neural precursors for allogeneic transplantation include the ability to provide an expandable, well-characterized, defined cell source which can form specific neuronal or glial subtypes.

SECOST: sequence-conformation-structure database for amino acid residues in proteins

The sequence-conformation-structure database for amino acid residues contains information on 114 828 individual residues derived from the spatial structures of 473 high-quality non-homologous proteins. The information in the database is obtained using a variety of different methods and can be used in various protein modeling applications.

Health related quality of life and disease severity in patients with alpha-1 antitrypsin deficiency

STUDY QUESTION

To describe health-related quality of life (HRQL) in individuals with alpha-1 antitrypsin (AAT) deficiency, examine the cross-sectional relationship between disease severity and HRQL, and explore changes in lung function and HRQL over time in a subset of these individuals.

MATERIAL/METHODS

Forty-five adults with AAT deficiency and moderate to severe emphysema completed the Chronic Respiratory Disease Questionnaire (CRQ), six-minute walk distance (6-MWD) and pulmonary function tests (PFTs). Twenty of the 45 were followed for two additional years with repeated measurements of CRQ and PFTs.

RESULTS

The mean +/- SD age was 49 +/- 8 years. Initial CRQ subscale scores were: dyspnea 17.5 +/- 4.3; fatigue 17.0 +/- 5.46; emotional function 33.1 +/- 8.67; and mastery 21.7 +/- 4.65. No relationship was found between percent predicted forced expiratory volume in one second (FEV1%) and CRQ score; 6 MWD and fatigue correlated significantly (r = 0.32, p < 0.05). Repeated PFT and CRQ measurements in 20 subjects showed statistically significant declines in FEV1 and slow vital capacity (SVC), but no change in CRQ scores.

CONCLUSIONS

Results suggest persons with AAT deficiency face challenges to HRQL that are similar to older adults with chronic pulmonary disease. Further research is needed on the nature of the relationship between disease severity and HRQL in this population.

Same-day discharge after endoscopic biliary sphincterotomy: observations from a prospective multicenter complication study. The Multicenter Endoscopic Sphincterotomy (MESH) Study Group

BACKGROUND

Same-day discharge after endoscopic biliary sphincterotomy (ES) is a common clinical practice, but there have been few data to guide appropriate selection of patients. Using a prospective, multicenter database of complications, we examined outcomes after same-day discharge as it was practiced by a variety of endoscopists and evaluated the ability of a multivariate risk factor analysis to predict which patients would require readmission for complications.

METHODS

A 150-variable database was prospectively collected at time of ES, before discharge and again at 30 days in consecutive patients undergoing ES at 17 centers. Complications were defined by consensus criteria and included all specific adverse events directly or indirectly related to ES requiring more than 1 night of hospitalization.

RESULTS

Six hundred fourteen (26%) of 2347 patients undergoing ES were discharged on the same day as the procedure, ranging from none at 6 centers to about 50% at 2 centers. After initial observation and release, readmission to the hospital for complications occurred in 35 (5.7%) of 614 same-day discharge patients (20 pancreatitis and 15 other complications, 3 severe). Of the same-day discharge patients, readmission was required for 14 (12.2%) of 115 who had at least one independently significant multivariate risk factor for overall complications (suspected sphincter of Oddi dysfunction, cirrhosis, difficult bile duct cannulation, precut sphincterotomy, or combined percutaneous-endoscopic procedure) versus 21 (4.2%) of 499 without a risk factor (odds ratio 3.1: 95% confidence interval [1.6, 6.3], p < 0.001). Of complications presenting within 24 hours after ES, only 44% presented within the first 2 hours, but 79% presented within 6 hours.

CONCLUSIONS

Same-day discharge is widely utilized and relatively safe but results in a significant number of readmissions for complications. For patients at higher risk of complications, as indicated by the presence of at least one of five independent predictors, observation for 6 hours or overnight may reduce the need for readmission.

A prospective randomized comparison of endoscopic ultrasound- and computed tomography-guided celiac plexus block for managing chronic pancreatitis pain

OBJECTIVE

Computed tomography (CT)-guided celiac plexus neurolysis has been used for controlling the chronic abdominal pain associated with intra-abdominal malignancy and chronic pancreatitis. Endoscopic ultrasound (EUS)-guided celiac plexus neurolysis has been reported to have some success in controlling pain from pancreatic cancer. The aim of this study is to assess the efficacy of EUS-guided celiac plexus block versus CT-guided celiac plexus block for controlling the chronic abdominal pain associated with chronic pancreatitis.

METHODS

Patients enrolled were randomly assigned to EUS-guided or CT-guided celiac plexus block. Pain scores were determined pre- and postceliac block for both techniques. Follow-up was obtained by a nurse at 1 day post-block, then weekly thereafter for 24 wk. Patients also rated overall experience with these procedures. The EUS celiac block was performed with a 22-gauge sterile needle inserted into the celiac region with guidance of real-time linear array endosonography followed by injection of 10 ml of bupivacaine (0.75%) and 3 ml (40 mg) of triamcinolone on both sides of the celiac area.

RESULTS

Twenty-two consecutive patients (10 men, 12 women), were ultimately enrolled in this study between 7/1/95 and 12/30/95; four patients were excluded for protocol violations. We performed EUS-guided celiac block in 10 patients and CT-guided celiac block in eight. A significant improvement in pain scores with reduction in pain medication usage occurred in 50% (five of 10) of patients having the EUS block. The mean postprocedure follow-up was 15 weeks (range: 8-24 wk). Persistent benefit was experienced by 40% of patients at 8 wk and by 30% at 24 wk. In the patients with CT block, however, only 25% (two of eight) had relief. The mean follow-up was 4 wk (range: 2-6 wk). Only 12% (one of eight) had some relief at 12 wk of follow-up. There were no complications. EUS-guided celiac block was the preferred technique among patients who experienced both techniques. A cost comparison between both celiac block techniques shows EUS to be less costly than CT.

CONCLUSIONS

EUS-guided celiac block provided more persistent pain relief than CT-guided block and was the preferred technique among the subjects studied. EUS-guided celiac block appears to be a safe, effective, and less costly method for controlling the abdominal pain that can accompany chronic pancreatitis in some patients.

Therapeutic biliary endoscopy

Therapeutic biliary endoscopy continues to evolve; some small but important developments were seen during the last year. Competing technologies are continuing to develop.

When is the dyspnea worth it? Understanding functional performance in people with alpha-1 antitrypsin deficiency

OBJECTIVE AND SIGNIFICANCE: To examine functional performance in people with emphysema because of alpha-1 antitrypsin (AAT) deficiency. A severe deficiency of AAT affects 1:3,500 to 1:1,670 Americans who can develop debilitating emphysema in the third to fifth decades of life.

DESIGN

Exploratory.

POPULATION

People with a severe deficiency of AAT. SAMPLE AND DEMOGRAPHICS: Thirty-three patients (21 men) with a mean age of 47 (SD = 7) years.

YEARS

Data were collected 1993-1996.

METHODS

Activities patients identified as important on the dyspnea subscale of the Chronic Respiratory Disease Questionnaire were categorized and interpreted within the context of an integrity framework (i.e., effectiveness--or connectedness-related).

FINDINGS

Patients identified over 25 activities. Effectiveness activities, such as bathing, were mentioned most frequently (78%). Connectedness activities, such as playing with children, were mentioned less often (22%) but were ranked more important. Two patients reviewed and supported the content validity of the framework.

CONCLUSIONS

Results offer insight into the activities patients with genetic emphysema choose to perform and the factors that influence the decision that "the dyspnea is worth it."

IMPLICATIONS

Identifying the activities people with AAT deficiency choose to perform and understanding why these activities are meaningful can guide interventions to help patients maintain a sense of integrity.

Serum concentration of calcium, 1,25 vitamin D and parathyroid hormone are not correlated with coronary calcifications. An electron beam computed tomography study

BACKGROUND

The amount of coronary artery calcification, measured using electron beam computed tomography, is correlated with the volume of coronary artery atherosclerotic plaque, the severity of stenosis by angiography, and with the likelihood of future cardiovascular events. The deposition of calcium in atherosclerotic plaques may also be influenced by determinants of calcium metabolism, thus contributing to the variance of the relation between coronary artery calcification and extent of atherosclerosis. Our objective was to determine whether this variance could be explained by differences in the parameters of calcium metabolism.

DESIGN AND METHODS

We measured serum concentrations of calcium, 1,25(OH)2 vitamin D and parathyroid hormone (PTH) in 50 subjects undergoing angiography for clinical indications, and evaluated the correlations between these concentrations and calcium deposition in the coronary arteries, and the ratio of calcium deposition to extent of atherosclerosis using coronary angiography.

RESULTS AND CONCLUSIONS

Serum concentrations of calcium 1,25(OH)2 vitamin D and PTH were not correlated with coronary calcification or the ratio of coronary calcification to the extent of coronary stenosis. We conclude that, in subjects undergoing coronary angiography, the variance of the relationship between coronary atherosclerosis and coronary calcium is not a result of differences in serum concentrations of calcium, 1,25(OH)2 vitamin D or PTH.

FISH studies of the sperm of fathers of paternally derived cases of trisomy 21: no evidence for an increase in aneuploidy

Paternal nondisjunction accounts for approximately 5% of cases of trisomy 21. To test the hypothesis that, in some such cases, the fathers might be predisposed to meiotic nondisjunction, we utilized fluorescence in situ hybridization (FISH) to screen for aneuploidy in sperm. We analyzed sperm samples from ten males with a trisomy 21 offspring of paternal origin. Among these individuals, the overall frequency of disomy 21 was 0.15%, comparable to estimates of disomy 21 in the general male population. Furthermore, none of the ten fathers of trisomy 21 individuals had significantly elevated levels of disomic sperm. Thus, our results provide no evidence that the occurrence of a trisomy 21 conceptus of paternal origin imparts an increased risk of trisomy in subsequent pregnancies.

Outcome after treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma

BACKGROUND

Treatment of differentiated thyroid cancer has been studied for many years, but the benefits of extensive initial thyroid surgery and the addition of radioiodine therapy or external radiation therapy remain controversial.

OBJECTIVE

To determine the relations among extent of surgery, radioiodine therapy, and external radiation therapy in the treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma.

DESIGN

Analysis of data from a multicenter study.

SETTING

14 institutions in the United States and Canada participating in the National Thyroid Cancer Treatment Cooperative Study Registry.

PATIENT

385 patients with high-risk thyroid cancer (303 with papillary carcinoma and 82 with follicular carcinoma).

MEASUREMENTS

Death, disease progression, and disease-free survival.

RESULTS

Total or near-total thyroidectomy was done in 85.3% of patients with papillary carcinoma and 71.3% of patients with follicular cancer. Overall surgical complication rate was 14.3%. Total or near-total thyroidectomy improved overall survival (risk ratio [RR], 0.37 [95% CI, 0.18 to 0.75]) but not cancer-specific mortality, progression, or disease-free survival in patients with papillary cancer. No effect of extent of surgery was seen in patients with follicular thyroid cancer. Postoperative iodine-131 was given to 85.4% of patients with papillary cancer and 79.3% of patients with follicular cancer. In patients with papillary cancer, radioiodine therapy was associated with improvement in cancer-specific mortality (RR, 0.30 [CI, 0.09 to 0.93 by multivariate analysis only]) and progression (RR, 0.30 [CI, 0.13 to 0.72]). When tall-cell variants were excluded, the effect on outcome was not significant. After radioiodine therapy, patients with follicular thyroid cancer had improvement in overall mortality (RR, 0.17 [CI, 0.06 to 0.47]), cancer-specific mortality (RR, 0.12 [CI, 0.04 to 0.42]), progression (RR, 0.21 [CI, 0.08 to 0.56]), and disease-free survival (RR, 0.29 [CI, 0.08 to 1.01]). External radiation therapy to the neck was given to 18.5% of patients and was not associated with improved survival, lack of progression, or disease-free survival.

CONCLUSIONS

This study supports improvement in overall and cancer-specific mortality among patients with papillary and follicular thyroid cancer after postoperative iodine-131 therapy. Radioiodine therapy was also associated with improvement in progression in patients with papillary cancer and improvement in progression and disease-free survival in patients with follicular carcinoma.

Contemporary treatment strategies for external pancreatic fistulas

BACKGROUND

Optimal treatment strategies for patients with external pancreatic fistulas have evolved with improved radiographic imaging and the development of transpapillary pancreatic duct stents. The aim of this study was to examine factors affecting fistula closure and develop a classification scheme to guide therapeutic interventions.

METHODS

Retrospective chart review was made of all patients with external pancreatic fistulas treated at our institution from January 1991 to January 1997. Side (partial) fistulas maintained continuity with the gastrointestinal tract; end (complete) fistulas had no continuity with the gastrointestinal tract.

RESULTS

Postoperative side fistulas resolved with medical treatment in 13 (86%) of 15 patients after a mean of 11 weeks of conservative management. Inflammatory side fistulas resolved with medical treatment in only 8 (53%) of 15 patients after a mean of 22 weeks; those that did not close initially did so with transpapillary stenting. End pancreatic fistulas never closed with medical treatment and were unable to be stented; therefore internal drainage or pancreatic resection was necessary to achieve closure. There were no differences in sepsis rates, Acute Physiology and Chronic Health Evaluation II scores, fistula site, total parenteral nutrition, somatostatin treatment, or initial fistula output between groups.

CONCLUSIONS

Classifying external pancreatic fistulas as to their pancreatic duct relationship and cause provides important prognostic and therapeutic information.

Structural analysis of peptide substrates for mucin-type O-glycosylation

The structures of three nine-residue peptide substrates that show differential kinetics of O-linked glycosylation catalyzed by distinct recombinant uridine diphosphate-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc transferases) were investigated by NMR spectroscopy. A combined use of NMR data, molecular modeling techniques, and kinetic data may explain some structural features required for O-glycosylation of these substrates by two GalNAc transferases, GalNAc-T1 and GalNAc-T3. In the proposed model, the formation of an extended backbone structure at the threonine residue to be glycosylated is likely to enhance the O-glycosylation process. The segment of extended structure includes the reactive residue in a beta-like or an inverse gamma-turn conformation and flanking residues in a beta-strand conformation. The hydroxyl group of the threonine to be glycosylated is exposed to solvent, and both the amide proton and carbonyl oxygen of the peptide backbone are exposed to solvent. The exchange rate of the amide proton for the reactive threonine correlated well with substrate efficiency, leading us to hypothesize that this proton may serve as a donor for hydrogen bonding with the active site of the enzyme. The oxygens of the residue to be glycosylated and several flanking residues may also be involved in a set of hydrogen bonds with the GalNAc-T1 and -T3 transferases.