Pattern of esophageal eosinophilic infiltration in patients with achalasia and response to Heller myotomy and Dor fundoplication.

Eosinophilic esophagitis (EoE) is now recognized as a common cause of dysphagia. Eosinophilic infiltration of the esophagus has also been associated with other conditions, such as gastroesophageal reflux disease (GERD); however, the incidence, pattern, and clinical significance of eosinophilic infiltration in achalasia are poorly documented. We sought to characterize this histological finding in patients undergoing Heller myotomy (HM) for achalasia. Ninety-six patients undergoing laparoscopic HM for primary achalasia between 1999 and 2008 were identified from a prospective database. Serial mid and distal per-endoscopic esophageal biopsies taken from patients before and after surgery were assessed for the presence of elevated intraepithelial eosinophils (EIEs). Slides from patients with reports suggestive of EIE were reviewed independently by two pathologists, and the highest eosinophil count/high-power field (eos/hpf) was recorded. Dysphagia scores (0 = none to 5 = severe dysphagia), GERD health-related quality of life scores (0 = best to 45 = worst), and 24-hour pH results were compared before and 3 months after surgery. We related the highest eos to the symptoms and response to HM. Data are presented as median (range). Paired t-test and Wilcoxon signed-rank test determined significance, *P < 0.05. Of 96 patients with achalasia, 50 had undergone pre-HM biopsies revealing EIE in 17/50 (34%), with a median of 3 eos/hpf (1-21). Two patients were found to have superimposed esophageal candidiasis. One patient met the pathologic criteria for EoE. Twenty-five of 50 (50%) postoperative biopsies demonstrated a median of 5 eos/hpf (1-62) for a total of 28/50 patients (56%) with EIE in either the preoperative or postoperative period. Four patients (8%) met the pathologic criteria for EoE, and two demonstrated persistent esophageal candidiasis. A decrease in eosinophils was found in 6/28 patients (21%) from 3/hpf (1-21) to 0.5/hpf (0-4). Increase in eosinophils was found in 22/28 patients (79%) from 0.5/hpf (0-8) to 5/hpf (1-62). Preoperative and postoperative dysphagia scores were available in 23 patients. Dysphagia scores improved in 22/23 patients. (3 [0-5] to 0 [0-2])*. Preoperative and postoperative GERD scores were available in 21 patients. GERD scores improved in 20/21 patients (10 [3-38] to 2 [2-14])*. Four of 13 patients (30.7%) demonstrated significant reflux in the postoperative period. No difference in clinical response to HM was detected between patients with preoperative EIE compared with patients with no EIE. No correlation between postoperative esophageal pH and eos was observed. A significant number of patients with achalasia demonstrate esophageal eosinophilic infiltration even at numbers demonstrable in patients with EoE (8% 4/50). While the interaction between achalasia and esophageal eosinophilic infiltration needs further investigation, this does not represent a distinct clinical entity. Thus, the presence of esophageal eosinophils in patients presenting with dysphagia should not preclude further work-up for other etiologies, including achalasia.

What is the optimal management of dysphagia in metastatic esophageal cancer?

BACKGROUND: The palliation of dysphagia in metastatic esophageal cancer remains a challenge, and the optimal approach for this difficult clinical scenario is not clear. We therefore sought to define and determine the efficacy of various treatment options used at our institution for this condition. METHODS: We reviewed a prospective database for all patients managed in an esophageal cancer referral centre over a 5-year period. All patients receiving palliation of malignant dysphagia were reviewed for demographics, palliative treatment modalities, complications, and dysphagia scores (0 = none to 4 = complete). The Wilcoxon signed rank test was used to determine significance (p < 0.05). RESULTS: During 2004-2009, 63 patients with inoperable esophageal cancer were treated for palliation of dysphagia. The primary treatment was radiotherapy in 79% (brachytherapy in 18 of 50; external-beam in 10 of 50; both types in 22 of 50), and stenting in 21%. Mean wait time from diagnosis to treatment was 22 days in the stent group and 54 days in the radiotherapy group (p = 0.003). Mean duration of treatment was 1 day in the stent group and 40 days in the radiotherapy group (p = 0.001). In patients treated initially by stenting, dysphagia improved within 2 weeks of treatment in 85% of patients (dysphagia score of 0 or 1). However, 20% of patients presented with recurrence of dysphagia at 10 weeks of treatment. In the radiotherapy group, the onset of palliation was slower, with only 50% of patients palliated at 2 weeks (dysphagia score of 0 or 1). However, long-term palliation was more satisfactory, with 90% of patients remaining palliated after 10 weeks of treatment. CONCLUSIONS: In inoperable esophageal cancer at our centre, radiation treatment provided durable long-term relief, but came at a high price of a long wait time for initiation of treatment and a long lag time between initiation of treatment and relief of symptoms. On the other hand, endoluminal stenting provided more rapid and effective early relief from symptoms, but was affected by recurrence of dysphagia in the long-term. It is now time for a prospective randomized trial to assess the safety and efficacy of combined-modality treatment with both endoluminal stenting and radiation therapy compared with either treatment alone.

Clinical predictors of achalasia.

Limited access to esophageal manometry (EM) may delay identification and treatment of patients with achalasia. In order to assess predictors to fast-track patients for manometric confirmation of achalasia, we compared the clinical, radiographic, and endoscopic characteristics of achalasia patients to patients with functional dysphagia without manometric features of achalasia (controls). Patients referred for esophageal manometry to assess functional dysphagia prospectively identified over a 12-month period were asked to participate in this study. The Achalasia Symptom Questionnaire (ASQ), a structured 11-question survey (score: 0-best, 67-worst), was completed by all consenting patients. ASQ scores, esophago-gastro-duodenoscopy and upper gastro-intestinal (UGI) contrast study findings were compared between patents with subsequently confirmed achalasia and those in whom achalasia was excluded by EM. Univariate logistic regression identified predictors that were tested by multivariate logistic regression to generate the model. Of the 803 EM performed over this 12-month period, 95 patients were referred specifically to assess functional dysphagia. Of these, 50 were confirmed to have achalasia, and 45 had dysphagia without manometric evidence for achalasia and hence comprised the control group. ASQ scores were higher in achalasia patients (37+/-13 versus 23+/-10). Endoscopy and/or contrast esophagogram reports were available in 92% achalasia patients and 80% controls. Significant predictors for achalasia identified on univariate logistic regression included ASQ score, abnormal findings on endoscopy, and contrast UGI study. Using multivariate logistic regression, we were able to accurately predict the probability of achalasia to be P where P=ey/(1+ey) and y=5.6+(0.089xASQ)+(2.088xEGD)+(3.083xUGI), e=exponential constant 2.7182, esophagogastroduodenoscopy (EGD) and UGI=0 if normal and 1 if abnormal. Dropping the predictor ASQ, the formula changes to y=-2.7+(1.987xEGD)+(2.861xUGI). Using only noninvasive investigations (i.e. eliminating EGD), the formula changes to y=-4.9653+(0.0951xASQ)+(3.4312xUGI). The probability of achalasia can be calculated in patients with functional dysphagia based on clinical, endoscopic, and radiographic findings allowing for a prioritization of EM studies.

Relationship between subjective and objective outcome measures after Heller myotomy and Dor fundoplication for achalasia.

BACKGROUND: The purpose of this study is to assess how subjective evaluation (heartburn, dysphagia, quality of life, and satisfaction) correlates with objective data after Heller myotomy and Dor fundoplication for achalasia. METHODS: A total of 53 consecutive patients with achalasia undergoing laparoscopic Heller myotomy and Dor fundoplication were studied prospectively. Subjective evaluation was done preop and postop using the Gastroesophageal Reflux Disease Health-Related Quality of Life instrument (GERD-HRQL; 0 = best, 45 = worse), 4-point dysphagia and heartburn scales (0 = best, 3 = worst), patient satisfaction scale (0 = very satisfied, 5 = incapacitated), and the SF-12 general health-related quality-of-life score. At 3 months postop, patients were asked to undergo objective evaluation with 24-h pH testing, manometry, and endoscopy. Data are expressed as median (interquartile range) and analyzed by Wilcoxon signed rank test or Mann-Whitney U test. RESULTS: Forty-nine patients were more than 3 months postsurgery. Comparing preop to postop, improvements were found in dysphagia [3 (2-3) to 0 (0-1)], heartburn [1 (0-2) to 0 (0-1)], GERD-HRQL [13.5 (6.3-22.5) to 2 (0-5)], satisfaction [3 (3-4) to 1 (0-1)], and SF-12 mental component summary [46 (37-56) to 58 (50-59)] and physical component summary [46 (36-53) to 55 (48-56)] scores (p < 0.0001 for all). Thirty-eight patients (78%) agreed to undergo objective testing, and complete data were available for 32 (65%). Four of 32 patients (12.5%) had evidence of reflux based on 24-h pH testing. Of nine patients with GERD-HRQL >5, only two had positive pH test (22%). Of 23 patients with GERD-HRQL <5, two had positive pH test (7%). Of four tested patients with moderate to severe heartburn, two had an abnormal pH test. There was no significant relationship between GERD-HRQL score and pH test results. Lower esophageal sphincter pressure (LESP) decreased from 24 (16-35) to 13 mmHg (11-17) (p < 0.001). There was no relationship between dysphagia score and postop absolute LESP or a decrease in LESP after operation. CONCLUSIONS: Laparoscopic Heller myotomy and Dor fundoplication is an effective treatment for achalasia. Subjective evaluation can document patient satisfaction and health-related quality of life but does not accurately reflect postop reflux. Twenty-four-hour pH study is required to accurately assess reflux disease.

Should laparoscopic paraesophageal hernia repair be abandoned in favor of the open approach?

BACKGROUND: The most appropriate approach to the repair of large paraesophageal hernias remains controversial. Despite early results of excellent outcomes after laparoscopic repair, recent reports of high recurrence require that this approach be reevaluated. METHODS: For this study, 60 primary paraesophageal hernias consecutively repaired at one institution from 1990 to 2002 were reviewed. These 25 open transabdominal and 35 laparoscopic repairs were compared for operative, short-, and long-term outcomes on the basis of quality-of -life questionnaires and radiographs. RESULTS: No difference in patient characteristics was detected. Laparoscopic repair resulted in lower blood loss, fewer intraoperative complications, and a shorter length of hospital stay. No difference in general or disease-specific quality-of-life was documented. Radiographic follow-up was available for 78% open and 91% laparoscopic repairs, showing anatomic recurrence rates of 44% and 23%, respectively (p = 0.11). CONCLUSIONS: Laparoscopic repair should remain in the forefront for the management of paraesophageal hernias. However, there is considerable room for improvement in reducing the incidence of recurrence.

There is no difference in the disease severity of gastro-oesophageal reflux disease between patients infected and not infected with Helicobacter pylori.

BACKGROUND: The role of Helicobacter pylori in gastro-oesophageal reflux disease (GERD) is controversial. AIM: To compare the severity of GERD in infected vs. non-infected patients, as part of an ongoing randomized controlled trial that examines the impact of H. pylori eradication on GERD-related outcomes. METHODS: Consecutive GERD patients underwent urea breath testing and completed validated GERD symptom severity, and quality of life questionnaires as well as, 24-h pH-metry. These parameters, as well as demographics and endoscopic findings were assessed in double-blinded fashion and compared between H. pylori-infected and non-infected subjects. RESULTS: Helicobacter pylori-infected GERD patients (n=50) were significantly older and less educated than non-infected patients (n=51). They also used proton pump inhibitors less often but had no difference in symptoms (as measured with both the Spechler's Activity Index and the Gastrointestinal Symptom Rating Scale), quality of life, endoscopic findings or 24-h pH-metry findings. CONCLUSION: This prospective, double-blind study demonstrates, using excellent GERD quantifying measures including validated symptom severity scores, endoscopy, and 24-h pH-metry, that there exist no clinically significant differences in clinical or laboratory-related GERD manifestations between H. pylori-infected and non-infected GERD patients.

Laparoscopic fundoplication: a model for assessing new technology in surgical procedures.

BACKGROUND: Surgical success has traditionally been judged from the surgeon's perspective. A more complete evaluation of outcome incorporates the patient's, surgeon's, and payor's perspectives. Because gastroesophageal reflux disease (GERD) is primarily a quality-of-life (QOL) problem, the evaluation of laparoscopic fundoplication (LF) is a useful model for evaluating outcomes from these 3 perspectives. METHODS: Between 1995 and 2000, 74 patients underwent primary LF for GERD. In addition to undergoing physiologic testing, 63 patients (85%) were evaluated with use of a disease-specific health-related QOL scale (GERD-HRQL), scored from 0 (no symptoms) to 45 (incapacitating symptoms). Thirty-three patients also completed a generic QOL questionnaire (SF-12), in which patient satisfaction was scored from 1 (very satisfied) to 5 (very dissatisfied). Preoperative and postoperative data were compared with use of the Wilcoxon signed rank test or the paired t test. RESULTS: The median GERD-HRQL score improved from 18 to 0 at 2 years postoperation (P <.01). The median satisfaction score improved from 5 to 1 (P <.01). The SF-12 summary scores also improved after 6 weeks postoperatively (P <.05). The mean +/- SD lower esophageal sphincter pressure rose from 7.3 +/- 4 mm Hg preoperatively to 17.5 +/- 6 postoperatively (P <.01), and the mean percentage of time that the esophagus was exposed to a pH of less than 4 declined from 14.7% +/- 12% to 1.1% +/- 2% (P <.01). The median operative time was 110 minutes, which declined with experience with the procedure (P <.01). Median postoperative stay was 2 days. CONCLUSIONS: In evaluating the outcomes of a new procedure, 3 overlapping points of view were addressed: the patient's (QOL, satisfaction), the surgeon's (physiologic changes), and the payor's (operating room time, hospital stay). With use of this framework, we found that LF for GERD improves QOL, corrects the physiologic abnormalities, and is associated with short hospitalization and operating time that declines with experience with the procedure.

Gastroesophageal reflux and hyperacidity in chronic renal failure.

The prevalence of H. pylori infection and PUD seem not to be different in CRF patients as compared with the general population. However, PUD in CRF patients seems to have some unique features-namely, lack of pain and higher associations with bleeding, with post-bulbar location, and with multiple ulcers. No increase in GERD has been proven in adults, but several studies demonstrate increased GERD in pediatric CRF patients. The causes of the increase in GERD may include delayed gastric emptying owing to altered myoelectric activity, or perhaps to an increased production of gastric acid, but evidence for the latter is small. Importantly, treating the problem may lead to better nutrition and higher albumin levels, thus improving patient prognosis.

Anti-Gag cytolytic T lymphocytes specific for an alternative translational reading frame-derived epitope and resistance versus susceptibility to retrovirus-induced murine AIDS in F(1) mice.

Murine AIDS (MAIDS) develops in susceptible mouse strains after infection with the LP-BM5 murine leukemia virus complex that contains causative defective, and ecotropic helper, retroviruses. We previously demonstrated that the MAIDS-resistant H-2(d) strains BALB/cByJ and C57BL/KsJ generate MHC class I (K(d)) restricted virus-specific CD8(+) cytolytic T lymphocytes (CTLs) that lyse cells expressing either defective or ecotropic gag proteins. In contrast, the congenic BALB.B and closely related C57BL/6J MAIDS-susceptible H-2(b) strains were unable to serve as a source of gag-specific CTLs (Schwarz and Green, 1994), suggesting that anti-gag CTLs might provide a basis for resistance to MAIDS. Although its susceptibility to MAIDS was unknown, the (BALB/c x C57BL/6J) F(1) (CBY6F(1)) strain could also produce H-2(d)-, but not H-2(b)-, restricted, anti-gag CTLs (Schwarz and Green, 1994). Because of this correlation between anti-gag CTLs and resistance to MAIDS, it was important to provide more direct evidence in support of CTL-mediated protection and to determine both the fine specificity of CByB6F(1) anti-gag CTLs, in comparison with the resistant C57BL/Ks and BALB/c strains, and the susceptibility of this F(1) strain to LP-BM5-induced MAIDS. We report here that no symptoms of MAIDS were observed in CBY6F(1) (H-2(dxb)) mice. For F(2) mice, in contrast to the high susceptibility of H-2(b/b) mice, 77% of H-2(d/d) and 81% of H-2(b/d) F(2) mice did not exhibit MAIDS after LP-BM5 infection. These results are in contrast to other published studies that concluded that susceptibility, rather than resistance, is dominant in F(1) (resistant x susceptible or susceptible x resistant) mice. We also show that CBY6F(1) anti-gag CTLs exhibit a fine specificity shared by the MAIDS-resistant BALB/c and C57BL/Ks strains, that is, the immunodominant gag epitope, SYNTGRFPPL, encoded by an alternative open reading frame. Together with our direct demonstration here that in vivo monoclonal antibody (mAb) depletion of CD8(+) T cells converts genetically resistant mice to MAIDS susceptibility, these data on the ability to mount anti-ORF2/SYNTGRFPPL, gag-specific CTL responses strongly suggest that CTLs are a primary factor in determining MAIDS resistance. Accordingly, given the K(d)-restricted nature of the CTLs, the main genetic determinant of resistance appeared to be the codominant expression of the resistant H-2(d) haplotype. Interestingly, however, 19% of H-2(d/b) and 23% of the H-2(d/d) F(2) mice had at least one clinical aspect of MAIDS, suggesting that a non-MHC genetic determinant(s) can negatively influence T-cell protection and thus disease outcome

Is Helicobacter pylori eradication associated with gastroesophageal reflux disease?

OBJECTIVES: A recent report has suggested an association between Helicobacter pylori eradication and the development of gastroesophageal reflux disease (GERD). We therefore assessed the incidence of GERD among comparable patients having undergone successful versus failed H. pylori eradication in a controlled trial. We also compared the H. pylori strains in the subjects that developed GERD to those that did not. METHODS: Patients with a history of proven duodenal ulcer and H. pylori infection were randomised into a H. pylori eradication study. Patients subsequently underwent gastroscopy with gastric biopsies every 3 months for 1 yr. At each visit, the presence of GERD symptoms and endoscopic esophagitis were noted, and the incidence of these variables among patients in whom H. pylori eradication was successful was compared to those in whom it was not. In a subgroup, the presence of the cagA, cagE, and vacA genotypes and of cagA antibodies were determined. RESULTS: Of 98 patients randomized into this study, 11 dropped out before determination of H. pylori eradication, leaving 87 patients with analyzable results. H. pylori eradication was successful in 63 (72%). By the end of the follow-up period, patients with GERD symptoms or endoscopic esophagitis were more prevalent in the successful than in the failed eradication group (37% [95% CI: 25-50%] vs 13% [95% CI: 3-32%], p = 0.04, 95% CI for the difference: 6-42%), as were patients with GERD symptoms alone (29% [95% CI: 18-41%] vs 8% [95% CI: 1-27%], p = 0.04, 95% CI for the difference: 4-36%) or esophagitis alone (21% [95% CI: 12-33%] vs 4% [95% CI: 0-21%], p = 0.10, 95% CI for the difference: 4-29%, respectively). Multivariate analysis revealed no significant association between the incidence of symptoms or esophagitis and age, gender, Quetelet index, caffeine or alcohol intake, smoking, weight change, or the presence of a hiatus hernia. There were also no differences in the prevalence of H. pylori genotypes from patients who developed GERD as compared to those who did not. CONCLUSIONS: In this patient population, the incidence of new GERD-type symptoms or endoscopic esophagitis was greater in patients in whom successful eradication was achieved. This difference does not appear to be attributable to weight gain, habits, or specific H. pylori strains.

An alternative translational reading frame encodes an immunodominant retroviral CTL determinant expressed by an immunodeficiency-causing retrovirus.

Recognition of virus-infected or transformed cells by CD8+ CTL requires a trimolecular complex composed of MHC class I, beta2-microglobulin, and a specific foreign peptide composed of 8 to 10 linear amino acids. The generation of such CTL epitopes has traditionally been thought to be from the primary open reading frame encoding the viral or tumor-associated proteins. In this report it is demonstrated that a viral CTL epitope can also be generated from an alternative reading frame. Using a combination of synthetic peptides and Sindbis or vaccinia expression systems, MHC class I Kd-restricted BALB/cByJ CTL directed against defective gag gene constructs of the LP-BM5 virus complex that causes murine AIDS were shown to have specificity for the antigenic peptide SYNTGRFPPL. This epitope is generated in a novel fashion from the second open reading frame (ORF2) of both the defective and ecotropic helper virus components of LP-BM5. Importantly, lysis of target cells expressing BM5 ecotropic helper, and/or defective viral gag, demonstrated that the SYNTGRFPPL epitope is generated during the course of a normal retroviral infection. Furthermore, MAIDS-resistant BALB/cByJ mice also generated secondary restimulated CTL specific for SYNTGRFPPL following in vivo priming with the LP-BM5 retroviral complex. These data suggest that retroviruses, and potentially other viruses and foreign genes, are capable of expressing T cell epitopes from alternative open reading frames. If one considers the influence of self peptides on T cell development, these "alternative reading frame-derived" peptides could provide an important additional influence on the functional T cell repertoire.

The treatment of peptic esophageal strictures.

Symptomatic stricturing of the esophagus complicates the course of about 10% to 15% of patients with gastroesophageal reflux disease, particularly if they are elderly or if there is an associated Barrett's esophagus. Treatment goals include relief of symptoms of reflux disease and dysphagia, and prevention of their recurrence. The main therapeutic option to date has been endoscopic dilation. Although more than 30% of patients require serial long term dilations, this proportion can be minimized by the concomitant use of long term, high dose proton pump inhibition. Indications for surgery include failure of medical management. It is too early to assess the impact of laparoscopic technology on the treatment of peptic strictures. At this time, well designed prospective comparative trials are needed to quantify better the cost effectiveness of available treatment strategies in the management of patients with esophageal peptic strictures.

Treatment of Barrett's esophagus.

Barrett's esophagus represents the most serious consequence of chronic gastroesophageal reflux disease (GERD), primarily because of its association with an increased incidence of esophageal adenocarcinoma. Specific therapy for Barrett's esophagus should lead to the complete regression of the metaplastic epithelium with adequate squamous reepithelialization. Ideally, this regression should be permanent and be associated with a reduction in the incidence of adenocarcinoma. Several reports in the literature have assessed the effects of H2-blocker treatment of Barrett's epithelium, but none has clearly documented a significant and consistent regression of the metaplastic epithelium. Proton pump inhibitors have been shown to be superior to H2 blockers in the treatment of patients with severe esophagitis. Despite initial enthusiasm, it does not appear that a significant regression of Barrett's epithelium can be achieved, even with high doses of proton pump inhibitors given for a prolonged period of time. Various groups have assessed the effects of antireflux surgery on the regression of columnar epithelium and dysplasia and its potential protective effect on the subsequent development of carcinoma. Overall, it appears from these reports that antireflux surgery, despite adequate symptomatic results, does not significantly and consistently lead to a reduction in length or disappearance of the Barrett's mucosa, and does not prevent the development of dysplasia and its progression to carcinoma. More recently, numerous authors have documented the regression of Barrett's mucosa by using various endoscopic thermal modalities. Technological advances including laser and photodynamic therapy have allowed for endoscopic mucosal ablation. Long term results are more encouraging when this mucosal ablation is associated with aggressive antireflux therapy (medical or surgical). Further studies are required before these exciting new therapies can be recommended. Currently, none of these approaches can obviate the need for continued endoscopic surveillance.

Duodenal perforation by a Greenfield filter: endoscopic diagnosis.

Despite its proven safety and efficacy, complications from the Greenfield vena cava filter have been described. We report the unusual case of a duodenal perforation by a filter in a 29-yr-old male. The diagnosis was made incidentally at endoscopy.

Pneumatosis cystoides intestinalis: laparoscopic features.

Pneumatosis cystoides intestinalis (PCI) is a condition characterized by the presence of gas-filled cysts in the submucosa or subserosa of the gastrointestinal tract. PCI has been described by various radiographic methods but its laparoscopic features have not been previously described. We report a case of a 77-yr-old male with marked ascites and radiographic evidence of pneumatosis cystoides intestinalis of the ileum who underwent a laparoscopy to determine the cause of his ascites. The characteristic laparoscopic features of PCI are described, and its radiographic features are reviewed.

A discrete 3' region of U6 small nuclear RNA modulates the phosphorylation cycle of the C1 heterogeneous nuclear ribonucleoprotein particle protein.

The C heterogeneous ribonucleoprotein particle (hnRNP) protein bind to nascent pre-mRNA and may participate in assembly of the early prespliceosome. Ser/Thr phosphorylation of the C1 hnRNP protein in HeLa nuclear extracts regulates its binding to pre-mRNA (S. H. Mayrand, P. Dwen, and T. Pederson, Proc. Natl. Acad. Sci. USA 90:7764-7768, 1993). We have now further investigated the phosphorylation cycle of the C1 hnRNP protein, with emphasis on its regulation. Pretreatment of nuclear extracts with micrococcal nuclease eliminated the phosphorylation of C1 hnRNP protein, but pretreatment with DNase did not, suggesting a dependence on RNA. Oligodeoxynucleotide-targeted RNase H cleavage of U1, U2, and U4 small nuclear RNAs did not affect the phosphorylation of C1 hnRNP protein. However, cleavage of nucleotides 78 to 95, but not other regions, of U6 small nuclear RNA resulted in an inhibition of the dephosphorylation step of the C1 hnRNP protein phosphorylation cycle. This inhibition was as pronounced as that seen with the serine/threonine protein phosphatase inhibitor okadaic acid. C1 hnRNP protein dephosphorylation could be completely restored by the addition of intact U6 RNA. Add-back experiments with mutant RNAs further delineated the minimal region essential for C1 protein dephosphorylation as residing in nucleotides 85 to 92 of U6 RNA. These results illuminate a hitherto unanticipated function of U6 RNA: the modulation of a phosphorylation-dephosphorylation cycle of C1 hnRNP protein that influences the binding affinity of this protein for pre-mRNA. This newly revealed function of U6 RNA is likely to play a very early role in the prespliceosome assembly pathway, prior to U6 RNA's entry into the mature spliceosome's active center.

Toxic megacolon complicating pseudomembranous enterocolitis.

PURPOSE: Toxic megacolon is a rare complication of pseudomembranous enterocolitis. We reviewed our recent experience with this complication. METHODS: The first five patients of the series were studied retrospectively, and six others were followed prospectively. RESULTS: Between June 1992 and May 1994, 11 patients (8 male, 3 female) developed toxic megacolon secondary to pseudomembranous enterocolitis. Mean age was 60.7 +/- 11.8 (range, 40-79) years. Presenting symptoms and signs included diarrhea, 100 percent; malaise, 91 percent; abdominal pain, 82 percent; abdominal distention, 82 percent; abdominal tenderness, 72 percent; anemia less than 12 gm, 72 percent; albumin less than 3 gm, 64 percent; tachycardia greater than 100, 55 percent; fever greater than 38.5 degrees celsius, 45 percent; shock or hypotension, 45 percent. Predisposing factors included antibiotics, 64 percent; immunosuppressants or chemotherapy, 36 percent; antidiarrheals, 27 percent; and barium enema in one patient. Five patients (45 percent) had more than one predisposing factor. X-rays showed transverse colon dilation and loss of haustrations in eight patients (72 percent), with a mean diameter of 9.9 +/- 3.4 cm. Flexible proctosigmoidoscopy showed pseudomembranes in all scoped patients, and toxin assay for Clostridium difficile was positive in all patients. One patient had emergency surgery. Ten patients were initially treated medically with nasogastric suction and intravenous resuscitation (90 percent) and antibiotics (100 percent), usually in the intensive care unit (80 percent). Four patients did not respond and underwent surgery; two others improved, then deteriorated, and also underwent surgery. Altogether, 7 of 11 patients (64 percent) underwent surgery. Three patients (27 percent) responded well to medical treatment. One patient was deemed too ill to undergo surgery and died. Mean delay to surgery was 3.0 +/- 1.3 days. No sealed or overt perforation was found at laparotomy. All patients who underwent surgery had a subtotal colectomy, with either a Hartmann's stump (71 percent) or a mucous fistula (29 percent). Eventually, five of seven patients who were operated on and two of four medically treated patients died (overall mortality, 64 percent). Only one patient underwent closure of ileostomy and anastomosis. CONCLUSION: Toxic megacolon complicating pseudomembranous enterocolitis is a serious problem that carries a high morbidity and mortality rate, regardless of treatment.

In vivo measurement of feline esophageal tone.

Using an isotonic recording device (barostat), we assessed feline esophageal smooth and striated muscle tone in vivo and determined the effects of a cholinergic agonist (bethanechol) and antagonist (atropine) and the effect of body position on this tone. Studies were performed on six cats under light intravenous ketamine anesthesia. Two parameters were analyzed: compliance and resistance to initial stretch (resting tone). Smooth muscle compliance (0.51 +/- 0.03 ml/mmHg) was significantly greater than that of the striated muscle section (0.26 +/- 0.02 ml/mmHg; P = 0.0260). Resting tone was low in both esophageal sections. Neither atropine nor bethanechol had any significant effect on the two tone parameters measured in smooth muscle. Change in body position had no influence on the intraesophageal balloon volume. We conclude that esophageal wall compliance varies according to location (smooth vs. striated muscle) and that esophageal smooth muscle tone is not under cholinergic excitatory control. Isotonic recording in vivo should allow further investigations of the nature of the neural and myogenic control of esophageal tone and of the relationships between phasic and tonic activity.

Measurement of human esophageal tone in vivo.

BACKGROUND: Conventional perfused manometry has led to extensive study of phasic contractile activity in the human esophagus, but little is known about esophageal tonic activity. The aims of this study were to assess esophageal smooth and striated muscle tone and the effect of a smooth muscle relaxant (amyl nitrite, 0.3 mL inhalation) on this tone. METHODS: Using a computerized isobaric recording system (barostat), esophageal tonic activity in 13 healthy subjects was recorded. Two parameters were analyzed: compliance and resistance to initial stretch (resting tone). RESULTS: The smooth muscle esophagus was significantly more compliant but presented a greater resistance to initial stretch than the striated muscle section. Amyl nitrite affected only the smooth muscle section, significantly increasing compliance and decreasing the resistance to initial stretch. Significant chest pain and/or discomfort occurred only during striated muscle esophagus distension (10 of the 13 subjects at 25 mm Hg distending pressure). CONCLUSIONS: Active tone is present in the smooth muscle esophagus and can be modulated by a smooth muscle relaxant. Compliance and resting tone differ between the smooth and striated muscle segments of the esophagus. Assessment of tone in patients with esophageal motor disorders and noncardiac chest pain should provide further insights into these disorders.