The AMOR study: a randomized, double-blinded trial of omeprazole versus ranitidine together with amoxycillin and metronidazole for eradication of Helicobacter pylori

BACKGROUND

Besides antibiotics, additionally effective acid inhibition is necessary for the eradication of Helicobacter pylori.

OBJECTIVE

To assess the significance of acid suppression and, in particular, treatment with proton pump inhibitors (PPIs) compared with H2 receptor antagonists (H2 RAs). The primary target parameter for the study was H. pylori eradication. In addition, the ulcer healing rate, speed of pain reduction, score for gastritis in the antrum and gastric body, and rate of side effects were recorded.

DESIGN

Randomized, double-blinded, multicentre study.

PARTICIPANTS

A total of 456 patients between the ages of 18 and 80 years with H. pylori-positive duodenal ulcers were included in the study.

METHODS

Using a randomization list, patients were assigned either to a treatment group receiving omeprazole 40 mg once daily, amoxycillin 750 mg three times a day, and metronidazole 500 mg three times a day (OAM), or to a group receiving ranitidine 300 mg once daily, amoxycillin 750 mg three times a day, and metronidazole 500 mg three times a day (RAM). The treatment period was 7 days in both groups. Long-term acid-suppressant treatment was not given.

RESULTS

The eradication rate was 87.1% (169/194, intention to treat [ITT]) in the OAM group and 77% (137/ 178, ITT) in the RAM group. The difference of 10.1% (95% CI 2.5-18%) is statistically significant (P= 0.0104). The ulcer healing rate was 93.3% in the OAM group (181/194, ITT) and 92.1% in the RAM group (164/178, ITT, NS). With regard to the speed and intensity of pain reduction, the OAM group was superior to the RAM group. In patients in whom H. pylori eradication was successful, the reduction in the antral and gastric body gastritis score was significantly greater than in patients without eradication. In the OAM group, 39.1% of the patients (n = 90) reported one or more side effects, compared with 44.7% (n = 101) in the RAM group (P= 1.5449, NS).

CONCLUSION

Omeprazole (40 mg once daily in the morning) is significantly more effective than ranitidine (300 mg once daily in the morning) with respect to H. pylori eradication when used together with amoxycillin (750 mg three times a day) and metronidazole (500 mg three times a day) for a 7-day treatment period.

Specific detection and prevalence of Helicobacter heilmannii-like organisms in the human gastric mucosa by fluorescent in situ hybridization and partial 16S ribosomal DNA sequencing

Gastric infection with Helicobacter heilmannii (previously known as Gastrospirillum hominis) is invariably linked with the presence of chronic gastritis and the risk of developing low-grade mucosa-associated lymphoid tissue lymphoma in humans. In contrast to Helicobacter pylori, various H. heilmannii species colonize the stomachs of domestic animals, which might be a reservoir for transmission to humans (zoonosis). To identify the number and prevalence of different H. heilmanni types in humans, we analyzed 89 gastric biopsy samples histologically identified as H. heilmannii positive by fluorescence in situ hybridization. Of these gastric specimens, 84 (94.4%) contained a single H. heilmannii type. In five samples, however, two different H. heilmannii types were detected. The most prevalent species in monoinfected samples is H. heilmannii type 1, found in 78.5% (66 of 84) of the specimens, followed by a novel H. heilmannii-like organism (HHLO), HHLO type 4, identified in 9.6% (8 of 84) of tissue sections. H. heilmannii type 2 and a further HHLO type not described before, type 3, were found in 8.3% (7 of 84) and 1.2% (1 of 84) of the monoinfected samples, respectively. Additionally, HHLO type 5 with a 16S ribosomal DNA sequence identical to that of Helicobacter salomonis was found with a prevalence of 2.4% (2 of 89). Thirteen of these biopsy samples were also investigated by a PCR approach developed for this study that allows a Helicobacter-specific amplification of a variable portion of the 16S rRNA gene and subsequent sequencing. In total, five different types of HHLOs could be identified within these samples. We conclude that humans can be infected by at least five different HHLO types, which presumably have their origin in animal species like dogs, cats, and pigs.

Prediction of the quaternary structure of coiled coils: GCN4 leucine zipper and its mutants

A methodology for predicting coiled coil quaternary structure and for the dissection of the interactions responsible for the global fold is described. Application is made to the equilibrium between different oligomeric species of the wild type GCN4 leucine zipper and seven of its mutants that were studied by Harbury et al. Over the entire experimental concentration range, agreement with experiment is found in five cases, while in two other cases, agreement is found over a portion of the concentration range. These simulations suggest that the degree of chain association is determined by the balance between specific side chain packing preferences and the entropy reduction associated with side chain burial in higher order multimers.

Barrett's mucosa, Barrett's dysplasia and Barrett's carcinoma: diagnostic endoscopy without biopsy-taking does not suffice

Many gastroenterologists are of the opinion that endoscopic diagnosis of gastro-oesophageal reflux disease (GORD) suffices and that additional biopsies are not necessary. The data obtained from 1068 consecutive patients with histologically confirmed Barrett's oesophagus were analysed retrospectively. In 37.9% of the patients, the histological diagnosis of Barrett's oesophagus was an incidental finding, whereas 32.7% of Barrett's carcinomas were diagnosed only at histology but not during endoscopy. Of the Patients with dysplasia, 92.4% were diagnosed only by the pathologist. Our analysis shows that an endoscopic diagnosis suspicious for Barrett's mucosa is made in 62.1% of the cases, carcinoma in 70%, and dysplasia in only 7.6% of the cases. Also, because neoplasia is detected for the most part at the invasive carcinoma state, but not in the dysplasia stage, the diagnosis of Barrett's oesophagus, with and without dysplasia, needs to be improved by additional biopsies for histopathological investigation.

Down-regulation of Akt/PKB in senescent cardiac fibroblasts impairs PDGF-induced cell proliferation

OBJECTIVE

Cardiovascular diseases are the leading cause of death in the Western World, especially in the elder population. One pathophysiological component of cardiovascular disease is myocardial fibrosis, primarily derived from cardiac fibroblasts. Here we investigated the regulation of proliferation of fibroblasts from hearts of adult rats by platelet derived growth factor AA (PDGF-AA).

METHODS

Cardiac fibroblasts were isolated from adult Wistar rats. PDGF-induced cell proliferation was analysed by FACS. PDGF-receptor numbers were analysed by receptor binding assays. Using differential display, differentially expressed kinases were identified during ageing in vitro and confirmed by Northern and Western blotting. Transient overexpression of IRES-GFP constructs was used to analyse the role of the akt kinase on proliferation by FACS.

RESULTS

During in vitro senescence/aging of primary fibroblasts, the growth response to PDGF-AA was greatly reduced without alterations in its receptor number or affinity and without changes in downstream signalling via the MAP-kinase pathway. By using a differential display strategy selective for protein kinases, we identified reduced expression of Akt-1 kinase (PKB-alpha) in senescent rat cardiac fibroblasts. These findings were supported by data showing reduced expression of Akt-1 in heart samples from old humans. Overexpression of activated Akt-1 almost completely reconstituted PDGF-AA dependent cell proliferation in aged fibroblasts.

CONCLUSION

These results support an important role for Akt in senescence and regulation of cardiac fibroblast cell proliferation.

Helicobacter pylori infection: protection against Barrett's mucosa and neoplasia?

BACKGROUND

Since Helicobacter pylori (Hp) infection provokes intestinal and gastric metaplasia, the question arises whether the specialized metaplasia (Barrett's mucosa (BM)) and dysplasia or carcinoma in Barrett's epithelium seen in gastro-oesophageal reflux disease (GORD) might not also be correlated with Hp infection, or whether the latter offers protection against Barrett's oesophagus and Barrett's adenocarcinoma.

PATIENTS

Gastric and oesophageal biopsies obtained from a total of 2,201 patients were analysed retrospectively. 297 of these patients had GORD (age 53.5 +/- 13.4 years; m:f ratio 2.1:1), 1,192 patients had BM (age 62.8 +/- 14.6 years; m:f 2.3:1) with or without neoplasia. 1,054 of these patients were diagnosed as having BM alone, 138 patients having BM neoplasia (high-grade dysplasia or adenocarcinoma). Patients with BM and low-grade dysplasia were excluded from this study because of the uncertainty in differentiating low-grade dysplasia from regenerative epithelium. A total of 712 patients with non-ulcer dyspepsia (NUD; average age 40.0 +/- 16.1 years; m:f 0.3:1) served as a control group.

RESULTS

The percentage of Hp infection did not differ between patients with GORD with (53.3%)/without BM (51.4%) and neoplasia (47.8%), but is statistically significantly lower than in patients with NUD (65.7%).

CONCLUSION

Our analysis shows that patients with GORD and Hp infection have no increased risk for the development of BM or neoplasia in BM. Since Hp infection is significantly less frequent in GORD than in NUD patients, a protective effect of the Hp infection is a possibility worth discussing.

Acute measles gastric infection

We describe the case of a 44-year-old man who was referred for gastroscopy because of abdominal pain. During endoscopy, inflammatory changes of the antrum and corpus mucosa were clearly visible, and biopsy samples from the antrum and corpus mucosa were taken. At histology, routine hematoxylin and eosin staining showed characteristics indicative of so-called ex-Helicobacter pylori-gastritis that had developed after antibiotic treatment 2 years ago. Additional large, bizarre inclusion bodies and clusters of multinucleated giant cells were located in the surface epithelium and within the lamina propria. These giant cells had an appearance similar to that of Warthin-Finkeldey cells, which can be found during the prodromal phase of measles infection. Anti-measles virus immunochemistry showed a strong positivity for measles virus antigen within the giant cells. Based on these results, the final diagnosis of morbilliform gastritis was made. To our knowledge, no case of measles gastritis has been described in the literature. Our case report confirms the systemic character of measles virus infection and confirms that measles viral replication can involve the gastric mucosa in addition to the conjunctiva, lung, and intestina.

[50 years of Barrett esophagus. Current diagnostic possibilities in pathology]

The most important differential diagnosis of specialized intestinal columnar cell metaplasia (Barrett's-mucosa) is the intestinal metaplasia of the cardia mucosa (possibly caused by Helicobacter infection). Furthermore it happens from time to time that Barrett's regenerative epithelium is overdiagnosed as low-grade dysplasia (unequivocal intraepithelial neoplasia). This might explain the disappearance of many low-grade dysplasias during further follow-up. Mucosal adenocarcinomas are often underdiagnosed as dysplastic lesions. Therefore many authors tried to establish molecular methods for improvement of the diagnostic possibilities. Immunohistochemistry or PCR with p53 and HER 2-neu might give at least some help but a negative reaction does not exclude a neoplasia in every case. The gold standard is careful endoscopy and biopsy taking with good documentation of the endoscopical findings and most important still the routine H&E stain are the only reliable diagnostic tools.

Mesalazine inhibits activation of transcription factor NF-kappaB in inflamed mucosa of patients with ulcerative colitis

OBJECTIVES

The salicylate mesalazine is commonly used for the treatment of inflammatory bowel diseases, yet its precise mechanism of action is unknown. Because transcription factor NF-kappaB plays an important role in inflammatory bowel diseases, we investigated the effects of mesalazine therapy on NF-kappaB activation in patients with ulcerative colitis.

METHODS

A total of 20 patients with moderately active ulcerative colitis received mesalazine for 8 wk. Biopsies were taken before and after drug administration and analyzed for NF-kappaB activation using an antibody specific for active NF-kappaB.

RESULTS

In biopsies of active ulcerative colitis but not in noninflamed mucosa, activation of NF-kappaB was detected predominantly in macrophages. Mesalazine therapy resulted, in a strong abrogation of NF-kappaB activation in situ.

CONCLUSIONS

Our results suggest that the therapeutic properties of mesalazine rely at least in part on the inhibition of NF-kappaB activation, resulting in the suppression of proinflammatory gene expression in the inflamed mucosa.

Ocular findings in Fryns syndrome

PURPOSE

To demonstrate the ocular histopathologic findings in Fryns syndrome, a multiple congenital anomaly syndrome, with characteristic features including Dandy-Walker malformation, cleft palate, diaphragmatic hernia, lung hypoplasia, distal limb anomalies and polyhydramnios. The prevalence is about 0.7 per 10,000 births. Reported ocular features include microphthalmus, "cloudy cornea", irregularities of Bowman's layer, thickened posterior lens capsule and retinal dysplasia.

METHODS

Case report. The ocular histopathologic and ultrastructural findings in a male fetus with Fryns syndrome who died immediately after his birth at 26th week of gestation are shown.

RESULTS

An abnormal Descemet's membrane was found in addition to "cloudy corneae". Electron microscopy demonstrated absence of the banded collagen fibrils in Descemet's membrane, indicating corneal endothelial dysfunction. Otherwise, the eye was morphologically normal for its age; none of the other reported ocular features of Fryns syndrome were found.

CONCLUSION

Corneal endothelial dysfunction might cause abnormal composition of anterior Descemet's membrane and could contribute to the "cloudy cornea" known to occur in Fryns syndrome.

Effects of long-term treatment with proton pump inhibitors in gastro-oesophageal reflux disease on the histological findings in the lower oesophagus

BACKGROUND

The application of hyperplasia of the basal cell layer and elongation of the papillae in the squamous epithelium of the distal oesophagus, as histological criteria for the diagnosis of gastro-oesophageal reflux disease (GORD), continues to be controversial. An unanswered question is whether these changes may regress under long-term treatment with proton pump inhibitors (PPI). This fact prompted us to investigate the effect of PPI treatment on the histological changes observed in the lower oesophagus.

METHODS

295 patients with endoscopically confirmed erosive GORD were investigated by endoscopy/biopsy prior to and during the course of a 12-month PPI treatment regimen (8 weeks acute treatment with 30 mg lansoprazole/day followed by long-term treatment with 15 or 30 mg lansoprazole or 20 mg omeprazole/day). The parameters studied were the frequency of ulcers and erosions and the hyperplasia of the basal cell layer and elongation of the papillae prior to treatment and on day 56 (D56), after 6 months (M6) and after 12 months (M12) of treatment.

RESULTS

In the various treatment groups, the results showed no statistically significant differences. Ulcers and erosions (prior to treatment 21% and 31%, respectively) were detected statistically significantly less frequently under PPI treatment (ulcers, D56: 1%, M6 and M12, 0%; erosions, D56: 2%, M6: 4%, M12, 3%). While high-grade hyperplasia of the basal cell layer and elongation of the papillae was found in 51% of the cases prior to treatment, the corresponding figures were only 3% (D56, M6) and 2% (M12). In contrast, the percentage of cases with normal oesophageal epithelium increased from 8% before treatment to 55% (D56), 66% (M6) and 63% (M12).

CONCLUSIONS

Our study shows not only that erosions and ulcers heal under PPI treatment, but also that hyperplasia of the basal cell layer and elongation of papillae in the squamous epithelium of the oesophageal mucosa may normalize, and are thus presumably not 'normal physiological variants'.

DoMCoSAR: a novel approach for establishing the docking mode that is consistent with the structure-activity relationship. Application to HIV-1 protease inhibitors and VEGF receptor tyrosine kinase inhibitors

DoMCoSAR is a novel approach for statistically determining the docking mode that is consistent with a structure-activity relationship. The approach establishes the binding mode for the compounds in a chemical series with the assumption that all molecules exhibit the same binding mode. It involves three stages. In the first stage all molecules that belong to a given chemical series are docked to the active site of the protein target. The only bias used in the docking at this stage involves the location of the protein binding site. Coordinates of the common substructure (CS) that results from the unbiased docking are then clustered to establish the major substructure docking modes. In the second stage all molecules are docked to the major docking modes (MDMs) with constraints based on the common substructure. The third stage generates, for the major docking modes, interaction-based descriptors that include electrostatic, VDW, strain, and solvation contributions. The problem of docking mode evaluation is now reduced to the question of which descriptor set is more predictive. To establish a quantitative comparison of the descriptor sets associated with the major docking modes, we use 50 instances of random 4-fold cross-validation. For each 4-fold cross-validation the predictive squared correlation coefficient (R(2)) is computed. t-Tests are applied to establish significance of the differences in mean R(2) for one docking mode versus another. We test the methodology on two test cases: HIV-1 protease inhibitors (Holloway et al. J. Med. Chem. 1995, 38, 305-317) and vascular endothelial growth factor (VEGF) receptor tyrosine kinase oxoindoles (Sun et al. J. Med. Chem. 1998, 41, 2588-2603). For both test cases there is statistically significant preference for the binding mode consistent with the X-ray structure. The appeal of this methodology is that researchers gain the objectivity of statistical justification for the selected docking mode. The methodology is relatively insensitive to subtle variations of the protein structure that include, but are not limited to, side chain and small backbone rearrangement during binding. In addition, predictive models that result from the approach can be used to further optimize chemical series.

Ablation of Barrett's epithelium by endoscopic argon plasma coagulation in combination with high-dose omeprazole

BACKGROUND

Barrett's esophagus is a premalignant condition induced by gastroesophageal reflux. The aim of this prospective study was to assess the efficacy of argon plasma coagulation in combination with high-dose omeprazole therapy to ablate nondysplastic Barrett's epithelium.

METHODS

In 73 patients with histologically confirmed Barrett's epithelium, argon plasma coagulation was used in combination with maximal acid suppression (omeprazole 40 mg three times a day). Histologic and endoscopic changes were evaluated at 6- and 12-month intervals.

RESULTS

In 69 of 70 patients (98.6%) complete squamous regeneration was achieved after a median of 2 argon plasma coagulation sessions (range 1 to 5). During a median follow-up of 12 months (range 2 to 51 months) there has been no relapse or evidence of the development of dysplasia under continuous acid suppression. Three patients (4.3%) developed a mild stricture of the distal esophagus that resolved after a single session of bougie dilation.

CONCLUSIONS

In our experience, argon plasma coagulation in combination with high-dose omeprazole treatment is an effective and safe technique for complete ablation of nondysplastic Barrett's epithelium. Restoration of squamous mucosa after argon plasma coagulation appears to be long-lasting.

Endoscopic mucosal resection of early cancer and high-grade dysplasia in Barrett's esophagus

BACKGROUND & AIMS

In view of the mortality and morbidity rates of esophagectomy and the relatively large group of inoperable patients, local therapeutic techniques are required for high-grade dysplasia and early Barrett's cancer.

METHODS

A prospective investigation of endoscopic mucosal resection was conducted in 64 patients (mean age, 65 +/- 10 years) who had early carcinoma (61 patients) or high-grade dysplasia (3 patients) in Barrett's esophagus. Thirty-five patients met the criteria for low risk: macroscopic types I, IIa, IIb, and IIc; lesion diameter up to 20 mm; mucosal lesion; and histological grades G1 and G2 and/or high-grade dysplasia (group A). The remaining 29 patients were included in group B (high risk).

RESULTS

A total of 120 resections were performed, with no technical problems encountered. The mean number of treatment sessions per patient was 1. 3 +/- 0.6 in group A and 2.8 +/- 2.0 in group B (P < 0.0005). Only one major complication occurred, a case of spurting bleeding, which was managed endoscopically. Complete local remission was achieved significantly earlier (P = 0.008) in group A than in group B. In May 1999, complete remission had been achieved in 97% of the patients in group A and in 59% of those in group B; however, 1 patient in group A and 9 in group B are still undergoing treatment or awaiting the first check-up. During a mean follow-up of 12 +/- 8 months, recurrent or metachronous carcinomas were found in 14%.

CONCLUSIONS

Endoscopic mucosal resection of early carcinoma in Barrett's esophagus is associated with promisingly low morbidity and mortality rates. The procedure may offer a new minimally invasive therapeutic alternative to esophagectomy, especially in low-risk situations. Comparisons with surgical results will need to be done when the long-term results of this procedure become available.

Short Barrett: prevalence and risk factors

BACKGROUND

The incidence of adenocarcinoma at the gastro-oesophageal junction is on the increase. These carcinomas are usually diagnosed too late and thus have a poor prognosis. Only early diagnosis can improve the situation. Classical Barrett oesophagus (length, >3 cm) is a known precancerous condition. There is also specialized columnar epithelium (SCE) in the grossly unremarkable gastro-oesophageal transitional zone (short Barrett).

METHODS

To determine the frequency of SCE, 370 patients were investigated by gastroscopy (OGD) consecutively between September 1995 and February 1996.

RESULTS

Classical Barrett oesophagus was found to have an incidence of 4.6%. In contrast, microscopic evidence of SCE was observed in 13.6% of the cases. Patients with short Barrett presented with reflux symptoms (odds ratio (OR), 4.7), irregular zona serrata ('tongues') in the cardia (OR, 2.8), and reflux oesophagitis significantly more frequently. Patients with reflux symptoms and concomitant 'tongues', however, had an OR of 13.16. Careful history-taking, together with a subtle histologic work-up of the gastro-oesophageal transitional zone can improve the rate of detecting patients with short Barrett.

CONCLUSION

Patients with reflux symptoms and irregular zona serrata should be selectively biopsied at the gastro-oesophageal junction, even when the latter presents a grossly normal appearance, with the aim of detecting patients at risk of developing a Barrett carcinoma.

The differentiation of true adenomas from colitis-associated dysplasia in ulcerative colitis: a comparative immunohistochemical study

Adenomas in areas involved by ulcerative colitis (UCA) are difficult to identify because of their morphological similarity to ulcerative colitis-associated dysplasia (UCD) and have an uncertain biology. Recently, a set of morphopathologic criteria were published for the diagnosis of UCA versus UCD. As a first step to analyze these criteria, we studied p53 and bcl-2 expression in groups of UCA and UCD along with a sporadic adenoma control group. Ninety lesions from UC areas (62 patients) were examined, including 24 UCA without high-grade dysplasia (HGD) and 66 UCD consisting of 43 polypoid and 23 flat dysplastic lesions (29 with HGD). Immunohistochemical p53 and bcl-2 expression were evaluated semiquantitatively. P53-positive cases were significantly less frequent in the UCA (4%) versus the UCD group (30%, P = .01) and the polypoid UCD subgroup (35%, P = .005). Moderate or strong bcl-2 expression was significantly more frequent in the UCA than in the UCD group (96% v 70%, P = .01) and in the UCA versus both polypoid and flat UCD subgroups. Comparison of UCA with low-grade dysplastic polypoid UCD cases alone showed a difference just below significance for p53 (P = .07). p53 and bcl-2 expression rates were very similar in the UCA group and the sporadic adenoma (n = 25) control group. These results show that UCA has phenotypic features more similar to sporadic adenomas than UCD and supports the concept that adenomas in UC have a biology different from UC-associated dysplasia.

Differential expression of mucins and trefoil peptides in native epithelium, Barrett's metaplasia and squamous cell carcinoma of the oesophagus

BACKGROUND AND AIMS

In humans, trefoil peptides (TFF peptides) and some mucins have been reported to be expressed in a cell-specific manner at mucosal surfaces of normal gastrointestinal tissues. Neoplastic conditions cause characteristic changes of these expression patterns. To study such patterns in Barrett's metaplasia and squamous cell carcinoma of the oesophagus (SCC), the distribution of MUC1, MUC2, MUC5AC and the three TFF peptides (TFF1, TFF2 and TFF3) was investigated.

METHODS

In 40 archival samples of SCC and in 21 samples of Barret's metaplasia, expression of the three mucins and two TFF peptides (TFF1 and TFF2) was assessed by specific antibodies. Reverse transcriptase/polymerase chain reaction amplification (RT-PCR) was performed on frozen tissue samples from the 11 biopsies of SCC for the three TFF peptides.

RESULTS

Immunohistochemical tests for MUC2 and TFF2 were negative both in samples of Barret's metaplasia and in SCC. MUC1 expression was detected in 57.5% of the tumour samples, while TFF1 and MUC5AC were found in 10% and 7.5% of the cases respectively. In Barrett's metaplasia MUC1 was detected in 90.5% of the cases and TFF1 and MUC5AC in all of them. RT-PCR analysis revealed a more complex pattern: TFF1 and TFF3 expressed the corresponding mRNA in all samples investigated; the third member, TFF2, was active in 45.5% of the carcinoma biopsies and not in the corresponding native tissue.

CONCLUSIONS

This finding in oesophageal carcinoma contrasts with the situation found in normal and neoplastic stomach epithelium where TFF1 and TFF2 are found co-expressed and TFF3 remains silent. Interestingly, MUC1 is expressed in a significant proportion of SCC. Both in Barett's metaplasia and in SCC the expression of MUC5AC mirrors the TFF1 synthesis in intensity and spatial distribution.

Do active site conformations of small ligands correspond to low free-energy solution structures?

We compare the low free energy structures of ten small, polar ligands in solution to their conformations in their respective receptor active sites. The solution conformations are generated by a systematic search and the free energies of representative structures are computed with a continuum solvation model. Based on the values of torsion angles, we find little similarity between low energy solution structures of small ligands and their active site conformations. However, in nine out of ten cases, the positions of 'anchor points' (key atoms responsible for tight binding) in the lowest energy solution structures are very similar to the positions of these atoms in the active site conformations. A metric that more closely captures the essentials of binding supports the basic premise underlying pharmacophore mapping, namely that active site conformations of small flexible ligands correspond to their low energy structures in solution. This work supports the efforts of building pharmacophore models based on the information present in solution structures of small isolated ligands.

Adenocarcinoma in an ileal pouch after prior proctocolectomy for carcinoma in a patient with ulcerative pancolitis

We report the first known case of pouch carcinoma in a 35-year-old female patient following proctocolectomy for adenocarcinoma in ulcerative pancolitis with backwash ileitis. Pouch cancer was diagnosed 2 years after the pelvic pouch procedure, illustrating that there might be a risk of pouch cancer in such patients. Adenocarcinoma arising in an ileoanal reservoir is rare. Two other cases have been reported: both patients concerned were believed to have developed cancer in small areas of residual remaining rectal mucosa.

[Short-term triple therapy with pantoprazole, amoxicillin and metronidazole in Helicobacter pylori infection]

BACKGROUND

The present study was conducted to investigate the efficacy and tolerability of a 7-day treatment with pantoprazole, amoxicillin and metronidazole for the eradication of Helicobacter pylori (H. pylori) infection.

PATIENTS AND METHODS

Fifty patients (26 male, 24 female, age 18 to 86, mean 54 years) with an active duodenal (n = 25) or gastric ulcer (n = 25) were recruited into the study, 48 patients being H. pylori positive at the study start. Patients were treated with pantoprazole (40 mg bid), amoxicillin (1 g bid) and metronidazole (500 mg bid) for 7 days and for another 21 days with pantoprazole (40 mg/od). Four weeks after the end of study medications the patients were re-examined endoscopically and their H. pylori status was re-assessed using urease test, histology and 13C-urea-breath test.

RESULTS

In 39 of 48 intention to treat patients, H. pylori infection was cured, according to 81% (95%-CI = 67 to 91%). In the per protocol population in 35 of 41 patients H. pylori was eradicated, which results in an eradication rate of 85% (95%-CI = 71 to 94%). Ulcer healing was endoscopically confirmed in 45 of 48 patients (94%; 95%-CI = 83 to 99%) after 8 weeks. Six of 50 patients (12%) reported mild to moderate probable side-effects of the study medication. Cure of the infection was associated with a distinct reduction of the gastritis grade and activity.

CONCLUSION

A 7-day triple therapy using pantoprazole, amoxicillin and metronidazole is an effective and cost-effective alternative to regimens including clarithromycin for the treatment of H. pylori infection.

Dramatic increase of alpha-hydroxyaldehydes derived from plasmalogens in the aged human brain

Plasmalogens-substantial compounds of brain tissue--suffer degradation either by hydrolysis under production of aldehydes or by oxidation with lipid peroxylradicals by generation of plasmalogen epoxides. The latter react by addition of pentafluorobenzylhydroxylamine HCl (PFBHA HCL) under hydrolysis to alpha-hydroxyaldehydes which are immediately transformed to pentafluorobenzyloximes (PFBO). Likewise, free aldehydes are transformed to PFBO-derivatives. PFBO-derivatives of free aldehydes and PFBO-derivatives of alpha-hydroxyaldehydes were extracted and after trimethylsilylation quantified by GC/FID and by GC/MSD. The remaining aqueous phase, containing plasmalogens besides other lipids, was hydrolyzed by treatment with acid. The hydrolysis products of plasmalogens, long chain aldehydes, react with PFBHA HCl to produce PFBO-derivatives. These were also quantified by GC/FID. This method allows the quantification of plasmalogens, free aldehydes and plasmalogenepoxides in human brain samples to study changes in the relation of these compounds with increasing age. While the ratio of plasmalogens in respect to derived aldehydes seems to remain constant during life time, the quotient of plasmalogenepoxides to plasmalogens increases with age, indicating that lipid peroxidation processes are involved in the damage of plasmalogens in the brain of aged individuals, starting at an age of about 70 years.

[The status of diagnosis of Barrett esophagus. An analysis of 1000 histologically diagnosed cases]

OBJECTIVE

To evaluate the quality of diagnosis in cases of Barrett's oesophagus (BOe). It was examined whether: (1) there had been regular pre-treatment investigations;(2) characteristic mucosal changes had been recognized by endoscopy; (3) a diagnosis of intraepithelial neoplasia had been made more often than of advanced Barrett carcinoma.

PATIENTS AND METHODS

Endoscopic and associated bioptic reports on 1000 consecutive patients with histologically confirmed BOe, seen between 1990 and 1995, were analysed. (Average age was 63 +/- 14.3 years; male to female ratio: 2.2:1).

RESULTS

In 85.1% of patients the histological diagnosis was BOe without dysplasia. The neoplasias consisted of carcinoma in 8.8%, suspected carcinoma in 0.5%, actual or suspected low-grade dysplasia in 4.6%, actual or high-grade dysplasia in 1.0%. Endoscopic diagnosis in cases without neoplasia was in 60.8% correct for actual BOe or suspected BOe. At endoscopy dysplasia was suspected in 5.4%. The diagnosis or suspected diagnosis of Barrett's carcinoma was correct in 69%. Repeat endoscopy a year after the initial diagnosis was performed in 9.4% with BOe and no neoplasia. Repeat endoscopy was performed in 37.5% of patients with an initial diagnosis of suspected low-grade dysplasia, in 43.3% with low-grade dysplasia, in 42.9% of suspected high-grade and in 100% of actual high-grade dysplasia.

CONCLUSION

Neoplasia in Barrett's oesophagus is found too late. Only half of the histologically confirmed cases are found by endoscopy and follow-up is not sufficient.

Predicting leucine zipper structures from sequence

The leucine zipper structure is adopted by one family of the coiled coil proteins. Leucine zippers have a characteristic leucine repeat: Leu-X6-Leu-X6-Leu-X6-Liu (where X may be any residue). However, many sequences have the leucine repeat, but do not adopt the leucine zipper structure (we shall refer to these as non-zippers). We have found and analyzed residue pair patterns that allow one to identify correctly 90% of leucine zippers and 97% of non-zippers. Simpler analyses, based on the frequency of occurrence of residues at certain positions, specify, at most, 65% of zippers and 80-90% of non-zippers. Both short and long patterns contribute to the successful discrimination of leucine zippers from non-zippers. A number of these patterns involve hydrophobic residues that would be placed on the solvent-exposed surface of the helix, were the sequence to adopt a leucine zipper structure. Thus, an analysis of protein sequences has allowed us to improve discrimination between leucine zippers and non-zippers, and has provided some further insight into the physical factors influencing the leucine zipper structure.

Method for predicting the state of association of discretized protein models. Application to leucine zippers

A method that employs a transfer matrix treatment combined with Monte Carlo sampling has been used to calculate the configurational free energies of folded and unfolded states of lattice models of proteins. The method is successfully applied to study the monomer-dimer equilibria in various coiled coils. For the short coiled coils, GCN4 leucine zipper, and its fragments, Fos and Jun, very good agreement is found with experiment. Experimentally, some subdomains of the GCN4 leucine zipper form stable dimeric structures, suggesting the regions of differential stability in the parent structure. Our calculations suggest that the stabilities of the subdomains are in general different from the values expected simply from the stability of the corresponding fragment in the wild type molecule. Furthermore, parts of the fragments structurally rearrange in some regions with respect to their corresponding wild type positions. Our results suggest for an Asn in the dimerization interface at least a pair of hydrophobic interacting helical turns at each side is required to stabilize the stable coiled coil. Finally, the specificity of heterodimer formation in the Fos-Jun system comes from the relative instability of Fos homodimers, resulting from unfavorable intra- and interhelical interactions in the interfacial coiled coil region.

Prediction of quaternary structure of coiled coils. Application to mutants of the GCN4 leucine zipper

Using a simplified protein model, the equilibrium between different oligomeric species of the wild-type GCN4 leucine zipper and seven of its mutants have been predicted. Over the entire experimental concentration range, agreement with experiment is found in five cases, while in two cases agreement is found over a portion of the concentration range. These studies demonstrate a methodology for predicting coiled coil quaternary structure and allow for the dissection of the interactions responsible for the global fold. In agreement with the conclusion of Harbury et al., the results of the simulations indicate that the pattern of hydrophobic and hydrophilic residues alone is insufficient to define a protein's three-dimensional structure. In addition, these simulations indicate that the degree of chain association is determined by the balance between specific side-chain packing preferences and the entropy reduction associated with side-chain burial in higher-order multimers.

Stimulation of B-cell lymphopoiesis by interleukin-7 leads to aggravation of murine leishmaniasis

The effect of recombinant interleukin-7 (IL-7) on the clinical course of murine leishmaniasis and the development of the accompanying immune response was investigated. Previously, IL-7 has been shown to possess stimulatory capacity for different cell types of the immune and haematopoietic system critically involved in the defence against Leishmania major (L. major), such as macrophages which are activated for the elimination of the parasite by IL-7. In contrast to these in vitro data, the present study indicates that treatment of genetically susceptible BALB/c mice with IL-7 at the onset of the infection leads to enhanced lesion development and a significantly accelerated death of the animals. This was correlated with a 40-fold increased parasite burden in spleens and lymph nodes. While the specific antibody response against L. major was not altered and lymphocytes of IL-7-treated mice produced comparable amounts of the T-helper type-2 (Th2) cytokines IL-4 and IL-10, less interferon-gamma (IFN-gamma) was measurable after antigenic stimulation of lymph node and spleen cells in vitro. One of the major changes appearing by the first week after infection in IL-7-treated mice was the increase of the total cell number in spleen and lymph nodes draining the local infection. Analysis of the cellular composition revealed that the enhanced cellularity was predominantly due to a rise in the B-cell compartment. Since antigen presentation by B cells has been implicated in the development of Th2 cells, the disease-aggravating activity of IL-7 is thought to be primarily due to augmentation of B lymphopoiesis.

Interleukin-10 inhibits antimicrobial activity against Leishmania major in murine macrophages

The stimulation of macrophages is of importance to the defense against intracellularly replicating microorganisms such as Leishmania. In this study the direct effect of recombinant interleukin-10 (IL-10) on the leishmanicidal effector functions of murine peritoneal or bone marrow derived macrophages was investigated. IL-10 almost completely inhibited the killing of intracellular leishmania at concentrations above 10 ng/ml. This inhibitory effect was independent of the stimulus used as the activation of macrophages by IFN-gamma and IL-7, recently shown to possess macrophage activating properties, were suppressed by IL-10. Kinetic experiments revealed that IL-10 must be present during the process of macrophage activation and that the leishmanicidal effector function of fully activated macrophages was not influenced. Furthermore, in the absence of exogenously added IL-10, the addition of neutralizing antibodies against IL-10 or IL-10-specific antisense phosphorothioate DNA-oligonucleotide led to an enhanced killing of parasites after stimulation with either IFN-gamma or IL-7. In accordance with this, IL-10 mRNA was readily detectable in murine macrophages by PCR with reverse transcribed mRNA. These results indicate that IL-10, which is endogenously produced by macrophages, acts as an autocrine deactivating factor supporting the survival of the parasite.

Prediction of the folding pathways and structure of the GCN4 leucine zipper

A hierarchical approach is described for the prediction of the three-dimensional structure and folding pathway of the GCN4 leucine zipper. Dimer assembly is simulated by Monte Carlo dynamics. The resulting lowest energy structures undergo cooperative rearrangement of their hydrophobic core leading to side-chain fixation. The coarse-grained structures are further refined using a molecular dynamics annealing protocol. This produces full atom models with a backbone root-mean-square deviation from the crystal structure of 0.81 A. Thus, we demonstrate the predictive ability of our approach to yield high resolution structures of small coiled coils from their sequence.

Interleukin-7 enhances antimicrobial activity against Leishmania major in murine macrophages

Recently, it has been shown that interleukin-7 (IL-7) is able to induce secretion of cytokines and tumoricidal activity by human monocytes. This study shows that treatment of murine macrophages infected with Leishmania major with IL-7 without any other stimulus reduced the percentage of infected cells, as well as the parasite burden per cell, in a dose-dependent manner to a limited degree (45% reduction of the number of amastigotes per 100 macrophages). Simultaneous treatment of macrophages with gamma interferon and IL-7 led to nearly complete (> 99%) elimination of amastigotes. Addition of anti-tumor necrosis factor alpha or N omega-monomethyl-L-arginine acetate reversed the leishmanicidal effects of IL-7, and production of nitric oxide was induced in the presence of IL-7.