Megacystis-microcolon-intestinal hypoperistalsis syndrome and the absence of the alpha3 nicotinic acetylcholine receptor subunit

BACKGROUND & AIMS

The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disease of childhood that presents early with intestinal hypoperistalsis, hydronephrosis, and hydroureters. Transgenic mice that lack the alpha3 subunit containing nicotinic acetylcholine (nAChR) have a phenotype similar to that of MMIHS.

METHODS

We examined the expression of this subunit in control and MMIHS tissue derived from patients using in situ hybridization (ISH) and immunocytochemistry (ICC).

RESULTS

In controls, both techniques showed a wide distribution of alpha3 nAChRs present in ganglion cells, muscle, and epithelium. By contrast, most MMIHS tissue gave negative staining with ISH and variable results with ICC.

CONCLUSIONS

These observations are consistent with a lack of alpha3 nAChRs contributing to the pathogenesis of MMIHS.

An operative method for surgical revision of a late failure after endovascular repair of an abdominal aortic aneurysm

Endoleak is a well-recognized complication of endovascular aortic exclusion stent-grafts. The Vanguard device is anchored into the proximal aorta by an expandable stent surmounted by a circular array of metal hooks. Attempted removal of the whole prosthesis may therefore be technically difficult and result in damage of the aortic wall. Surgery for endoleak may be complicated and carry a mortality rate of 20% to 40%. We describe a simple surgical technique for repair of endoleaks associated with a Vanguard stent-graft, which would be applicable to other such devices. This method involves minimal disruption of the proximal stent and avoids problems that may arise from an attempt to completely remove the endovascular device.

LUCA-15 suppresses CD95-mediated apoptosis in Jurkat T cells

The candidate tumour suppressor gene, LUCA-15, maps to the lung cancer tumour suppressor locus 3p21.3. Overexpression of an alternative RNA splice variant of LUCA-15 has been shown to retard human Jurkat T cell proliferation and to accelerate CD95-mediated apoptosis. An antisense cDNA to the 3'-UTR of this splice variant was able to suppress CD95-mediated apoptosis. Here, we report that overexpression of LUCA-15 itself suppresses CD95-mediated apoptosis in Jurkat cells. This suppression occurs prior to the final execution stage of the CD95 signalling pathway, and is associated with up-regulation of the apoptosis inhibitory protein Bcl-2. LUCA-15 overexpression is also able to inhibit apoptosis induced by the protein kinase inhibitor staurosporine, but is not able to significantly suppress apoptosis mediated by the topoisomerase II inhibitor etoposide. These findings suggest that LUCA-15 is a selective inhibitor of cell death, and confirm the importance of the LUCA-15 genetic locus in the control of apoptosis.

In vivo and in vitro studies of immunoglobulin gene somatic hypermutation

Following antigen encounter, two distinct processes modify immunoglobulin genes. The variable region is diversified by somatic hypermutation while the constant region may be changed by class-switch recombination. Although both genetic events can occur concurrently within germinal centre B cells, there are examples of each occurring independently of the other. Here we compare the contributions of class-switch recombination and somatic hypermutation to the diversification of the serum immunoglobulin repertoire and review evidence that suggests that, despite clear differences, the two processes may share some aspects of their mechanism in common.

Nitric oxide mediates a therapeutic effect of nicotine in ulcerative colitis

BACKGROUND

Ulcerative colitis is a condition of nonsmokers in which nicotine is of therapeutic benefit.

AIMS

To examine the in vitro effect of nicotine on colonic smooth muscle activity and the role of nitric oxide (NO) as a mediator.

METHODS

Nicotine, 1-10 microM, was administered to strips of circular muscle from the distal sigmoid colon of 9 patients with active ulcerative colitis and 18 with colorectal cancer. The effect of electrical field stimulation (EFS) was examined before nicotine was added. Finally L-NAME, a NO synthetase inhibitor, was added before nicotine was administered again.

RESULTS

Muscle strips developed similar spontaneous resting tone. In response to EFS, ulcerative colitis tissue developed lower tensions than the controls. Nicotine significantly reduced the resting tone and peak tension after EFS, with a greater effect in controls. With L-NAME, peak tensions were increased more in ulcerative colitis than controls, and nicotine produced a much smaller reduction.

CONCLUSIONS

Nicotine reduces circular muscle activity, predominantly through the release of nitric oxide-this appears to be 'up-regulated' in active ulcerative colitis. These findings may explain some of the therapeutic benefit from nicotine (and smoking) in ulcerative colitis and may account for the colonic motor dysfunction in active disease.

The contribution of somatic hypermutation to the diversity of serum immunoglobulin: dramatic increase with age

Although somatic mutation contributes to the diversity of only a minor fraction of B cells in mouse spleen or blood, its contribution to the diversity of serum immunoglobulin is unknown. We have devised an immunoassay to monitor mutated antibodies in serum using a monoclonal antibody that recognizes a VK only when mutated at its major intrinsic hot spot. Mutation makes essentially no contribution to the diversity of endogenous serum IgM, IgG, or IgA in young mice. However, in response to environmental antigens, the titer of mutated immunoglobulin in T cell-proficient mice rises strikingly with age, such that the major proportion of serum immunoglobulin in adults is somatically mutated, with the mutation load in IgG being some 10-fold greater than in IgM.

LUCA-15-encoded sequence variants regulate CD95-mediated apoptosis

Using an expression cloning system to discover novel genes involved in apoptosis, we identified a 326 bp bone marrow cDNA fragment (termed Je2) that suppresses, upon transfection, CD95-mediated apoptosis in Jurkat T cells. Sequence homology revealed that Je2 maps to 3p21.3, to an intronic region of the candidate TSG LUCA-15 locus. It represents, in fact, an antisense transcript to the 3'-UTR of two novel splice variants of this gene. Overexpression of sequence representing one of these splice variants (a 2.6 kb cDNA termed Clone 26), inhibited proliferation of Jurkat cells and sensitized them to CD95-mediated apoptosis. This study therefore implicates the LUCA-15 gene locus in the control of apoptosis.

Crohn's disease incidence in Cardiff from 1930: an update for 1991-1995

OBJECTIVE

To report the incidence of Crohn's disease in the city of Cardiff between 1991 and 1995, in relation to the data of the preceding 65 years.

METHODS

The incidence of Crohn's disease was studied by collecting information from clinical records, the department of pathology database and a questionnaire sent to local family practitioners.

RESULTS

Eighty-four new patients with Crohn's disease, and resident in Cardiff, were diagnosed between 1991 and 1995. The mean incidence for this quinquennium was 56 cases per 10(6) population per year (95% confidence interval, 44-68). There was a female predominance, particularly in young adults, with an overall male to female ratio of 0.47. Colorectal disease was the most common site of disease at the time of diagnosis.

CONCLUSIONS

In relation to the findings of our previous studies, the data suggest that the overall incidence of Crohn's disease is now stable, but that the proportion with colorectal disease continues to increase and there is a marked female preponderance in Crohn's disease presenting in young people.

Endosonographic staging of 100 consecutive patients with esophageal carcinoma: introduction of the 8-mm esophagoprobe

Endoscopic ultrasound of esophageal carcinoma is conventionally performed using the 13-mm fiberoptic/ultrasound echoendoscope. However, the large diameter results in an inability to negotiate the primary tumor in 25% of patients. The aim of this study was first to determine whether use of the 8-mm esophagoprobe would overcome this problem and second to evaluate the accuracy of the smaller diameter instrument. One hundred consecutive patients with esophageal cancer underwent initial gastroscopy. Based upon the degree of luminal stenosis, patients were staged with either the conventional echoendoscope (luminal diameter > or = 15 mm) or the esophagoprobe (luminal diameter < 15 mm). The primary tumor was successfully negotiated in all subjects (echoendoscope 30, esophagoprobe 70) so that T- and N-staging was accomplished in every patient. Esophageal dilatation was performed in 12 patients (12%). The procedure was well tolerated and there were no complications, in particular no patient suffered esophageal perforation. The accuracy of the esophagoprobe for T-staging was 90% (19 out of 20) and that for N-staging was 75% (15 out of 20). This was similar to the accuracy of staging with the conventional echoendoscope, 90% (9 out of 10) for T-stage and 90% (9 out of 10) for N-stage. The esophagoprobe can safely and accurately stage patients with esophageal carcinoma, including those with high-grade stenoses.

ACP Best practice no 159. Examination of large intestine resection specimens

Macroscopic examination of large intestinal resection specimens by the surgical pathologist provides important diagnostic and prognostic information. This review summarises current recommended protocols and evidence based guidelines for gross description, dissection, and histological block selection in both neoplastic and non-neoplastic colorectal disease. Specific lesions discussed include colorectal cancer, polypectomies and polyposis syndromes, and inflammatory bowel disease. Microscopic examination is briefly described, with emphasis on certain pitfalls that might be encountered in routine practice. A section covering special techniques for the investigation of occult bleeding is included.

Anal cancer subtype reproducibility study

For histological subtyping of anal squamous carcinomas the WHO advocates a six-way subdivision, but it has been suspected that the six types cannot be reliably discriminated in practice. We conducted a blinded study involving slides from 103 consecutive cases, each slide being examined by three experts (from Denmark, Australia and UK) on two occasions at least 8 months apart. Agreement on subtypes was low: 72% between rounds within pathologist, 61% between pathologists. Even for the commonest, and most stably diagnosed, type, viz. large-cell keratinising squamous carcinoma, the intra- and interpathologist frequencies of confirmation were only 81% and 71%, respectively. The pathologist marked the picture as typical and his subtype diagnosis as certain 41% of times: even then confirmation frequencies were only 88% and 74%, respectively. Calculations, including kappa analyses, suggest that 26% of the typing variation was noise. The WHO scheme must be even more unreliable in everyday practice. We finally mention a recently demonstrated link between human papilloma virus (HPV) and certain types of anal cancer, which may well provide an additional argument for revising existing subtyping schemes.

Zinc has no effect on IL-3-mediated apoptosis of BAF-3 cells but enhances CD95-mediated apoptosis of jurkat cells

The feasibility of using a zinc-inducible gene expression system for the study of apoptosis-controlling genes in BAF-3 murine B cells and Jurkat human T cells was evaluated. Initially, cell sensitivity to a range of zinc concentrations was examined. It was found that zinc concentrations above 60 microM were toxic to BAF-3 cells and those above 50 microM were toxic to Jurkat cells. Secondly, the zinc concentration required to achieve maximal gene expression was examined. BAF-3 cells transiently transfected with the pMTCB6+/luciferase vector were exposed to zinc concentrations ranging from 0-120 microM, whilst stably transfected Jurkat cells were exposed to 0-70 microM zinc. At zinc concentrations nontoxic to each cell type, the maximum induction achieved was 20-fold (at 60 microM) in BAF-3 cells, and 7.5-fold (at 50 microM) in Jurkat cells. Thirdly, the effect of zinc on apoptosis was examined. It was shown that exposure to nontoxic zinc concentrations had no effect on IL-3 withdrawal-mediated apoptosis of BAF-3 cells. However, in the case of Jurkat cells, pre-exposure to zinc augmented CD95-mediated apoptosis. These results illustrate the importance of characterizing individual cell lines when using zinc-inducible gene expression systems.

Dissociation between Fas expression and induction of apoptosis in human islets of Langerhans

There is increasing evidence that inappropriate induction of apoptosis in pancreatic beta-cells may precede the development of type 1 diabetes in animal models and in man. One mechanism by which this has been proposed to occur involves up-regulation of the death receptor Fas on beta-cells, resulting in apoptosis of the Fas-bearing beta-cells upon ligation of the receptor. We have examined this hypothesis in isolated human islets of Langerhans and show that--in contrast to data obtained with rodent beta-cells--expression of Fas per se is not sufficient to allow induction of apoptosis upon addition of agonistic anti-Fas serum.

Diversification and selection mechanisms for the production of protein repertoires: lessons from the immune system

The physiological mechanism for producing antigen-specific antibodies is based on a two-phase neo-Darwinian process: the first phase consists of diversity generation (formation of the repertoire), and the second phase is antigen-mediated selection. In this article, we consider how the natural immunoglobulin gene-diversification processes can be exploited both in vivo and in vitro in order to allow the generation of novel antibody (and heterologous protein) repertoires.

Patterns of gastritis in patients with gastro-oesophageal reflux disease

BACKGROUND

The cause of inflammation in cardiac mucosa at the gastro-oesophageal junction (GOJ) is unclear, both gastro-oesophageal reflux disease (GORD) and Helicobacter pylori having been implicated.

AIMS

To describe patterns of gastritis in patients with symptomatic GORD.

METHODS

In 150 patients (126 normally located Z-line, 24 Barrett's oesophagus) with symptoms of GORD, biopsies were taken of the GOJ, corpus, and antrum. Inflammation was assessed using the updated Sydney System.

RESULTS

For the 126 patients with a normally located Z-line, biopsies of the GOJ revealed cardiac mucosa in 96, fundic mucosa in 29, and squamous mucosa in one. Inflammation in glandular mucosa at the GOJ was present in 99/125 specimens (79%), including 87/96 (91%) with cardiac mucosa and 12/29 (41%) with fundic mucosa. Inflammation in fundic mucosa was closely related to H pylori and active inflammation was only seen in its presence. Inflammation in cardiac mucosa was less closely linked to H pylori. When H pylori was present in cardiac mucosa (28/96, 29%) active inflammation was usually present (25/28, 89%). However, active inflammation was also found in 34/68 (50%) cardiac mucosa specimens without H pylori. Overall, 28/87 (32%) biopsies with carditis were colonised with H pylori and 59/87 (68%) were not. In H pylori colonised patients, inflammation was seen throughout the stomach, while in non-colonised patients, it was confined to cardiac mucosa.

CONCLUSIONS

Patients with symptomatic GORD had a high prevalence of carditis. This was of two types, H pylori associated and unassociated. Except on Giemsa staining, the two were morphologically identical, suggesting mediation by a similar immunological mechanism.

Serial endoscopic ultrasound in the assessment of response to chemoradiotherapy for carcinoma of the esophagus

The aim of the study was to assess whether endoscopic ultrasound (EUS) could accurately measure the locoregional response to chemoradiotherapy in patients with carcinoma of the esophagus. Seventeen patients with esophageal carcinoma underwent EUS examination before and on completion of chemoradiotherapy. The EUS findings were correlated with the results of histologic examination of the esophagectomy specimen. The accuracy of EUS in these patients was compared with the accuracy of EUS in a control group of 17 patients treated by surgery alone. In 16 of 17 patients EUS-determined tumor (T) stage was unchanged following treatment and in one patient there was T-stage progression. No patient demonstrated downstaging of the primary tumor according to classical EUS criteria. In 10 of 17 patients a reduction in maximum tumor depth of >/=2 mm was observed (range 2 to 18 mm). Histologic examination revealed that four patients with squamous cell carcinoma had experienced a complete pathologic response. These four patients had significantly lower posttreatment EUS tumor depths compared to patients without a complete response (5.0 vs. 9.0 mm; P <0.05). Based on the post-treatment EUS examination, the accuracy was 59% for T stage and 59&percnt for node (N) stage. The accuracy of EUS in patients treated by surgery alone was 94% for T stage and 94% for N stage, indicating a significant reduction in the accuracy of EUS in patients following chemoradiotherapy (P <0.05). The accuracy of EUS examination in patients with carcinoma of the esophagus treated by chemoradiotherapy was poor. EUS did not detect downstaging of the primary tumor, even in the presence of a complete pathologic response. EUS assessment of maximum tumor depth was a better measure of response to therapy.

Oesophageal and gastric cancer pathology reporting: a regional audit

AIM

To audit the information content of pathology reports of oesophageal and gastric cancer resection specimens in Wales.

METHODS

All such reports from the 16 NHS histopathology laboratories in Wales in a one year period were evaluated for their information content. Two standards were used: (1) best practice reporting, and (2) a minimum dataset required for informed patient management that included clear statements on histological tumour type, depth of tumour invasion, lymph node involvement, and completeness of excision.

RESULTS

282 reports were audited. Minimum standards were achieved in 77% of gastric resections (156/203) and 53% of oesophageal resections (42/79). All laboratories achieved minimum standards in some gastric cancer reports (range 50-100%); three laboratories did not achieve minimum standards in any oesophageal cancer reports (range 0-100%). Best practice reporting was achieved in only 20% of gastric and 18% of oesophageal cancer reports. Failure to include an explicit statement on completeness of excision or involvement of the oesophageal circumferential resection margin were the most frequent causes of inadequate reporting. Most other data items were generally well reported, but apparent inadvertent omission of just one item was noted in many of the substandard reports.

CONCLUSIONS

This audit shows the need to improve the information content of pathology reports in gastric and oesophageal cancer. The widespread implementation of template proforma reporting is proposed as the most effective way of achieving this. Multidisciplinary meetings of clinicians involved in cancer management should provide a forum for greater communication between pathologists and surgeons, and help to maintain standards of pathological practice.

Deficiency in CD22, a B cell-specific inhibitory receptor, is sufficient to predispose to development of high affinity autoantibodies

CD22 is a B cell-specific transmembrane glycoprotein that acts to dampen signals generated through the B cell antigen receptor (BCR): B cells from CD22-deficient mice give increased Ca2+ fluxes on BCR ligation. Here we show that this B cell hyperresponsiveness correlates with the development of autoantibodies. After the age of eight months, CD22-deficient mice developed high titers of serum IgG directed against double-stranded DNA; these antibodies were of multiclonal origin, somatically mutated, and high affinity. Increased titers of antibodies to cardiolipin and myeloperoxidase were also noted. The results demonstrate that a single gene defect exclusive to B lymphocytes is, without additional contrivance, sufficient to trigger autoantibody development in a large proportion of aging animals. Thus, CD22 might have evolved specifically to regulate B cell triggering thresholds for the avoidance of autoimmunity.

Rectal carcinoma: thin-section MR imaging for staging in 28 patients

PURPOSE

To evaluate the accuracy of thin-section magnetic resonance (MR) imaging (in-plane resolution, 0.6 x 0.6 mm) in the preoperative assessment of the depth of extramural tumor infiltration, which is a major prognostic indicator in rectal cancer.

MATERIALS AND METHODS

In a prospective study of 28 consecutive patients, preoperative MR imaging was performed. The tumor stage according to the TNM classification system and the measured depth of extramural tumor invasion in matched MR images and histopathologic slices were compared.

RESULTS

Preoperative MR imaging correctly indicated the histopathologic tumor stage in all 25 patients in whom comparisons were possible. The difference between the depth of extramural tumor measured on preoperative MR images and corresponding measurements on histopathologic slices of the resection specimen ranged from -5.0 mm to +5.5 mm (mean difference, +0.13 mm; 95% CI: -2.72, +2.98 mm), indicating good agreement. The mesorectal fascia, and the relation of the tumor to it, could be visualized in every case. In all five patients with involvement of the circumferential excision margins of resection specimens, extensive extramural invasion was identified on preoperative MR images.

CONCLUSION

Preoperative thin-section MR imaging accurately indicates the tumor stage of rectal cancer and depth of extramural tumor infiltration. It provides valuable information for identifying T3 tumors for preoperative adjuvant therapy in patients who are at high risk of failure of complete excision.

Outcome of oesophagogastric carcinoma in young patients

The survival of young patients (< or = 50 years of age) with carcinoma of the oesophagus or stomach has been reported to be poorer than that of their older counterparts. The aim of the current study was to review the outcome of such young patients with oesophagogastric cancer and to compare the outcome in patients with carcinoma of the oesophagus/cardia with patients with carcinoma of the more distal stomach. The study population was 50 patients. Tumour location was oesophagus/cardia (n = 33) and gastric body/antrum (n = 17). The most common presenting symptoms were weight loss (66%), epigastric pain (54%), dysphagia (50%), and heartburn (40%). Seventeen patients had experienced foregut symptoms for a period of > or = 6 months. These patients were more likely to have symptoms of gastro-oesophageal reflux disease and to have received acid suppression therapy than patients with shorter symptom durations. Only 20 patients underwent a potentially curative resection, while 10 underwent open and close laparotomy. The overall median survival was 7 months and the 5-year survival was 8%. Multivariate analysis revealed that surgical resection and UICC stage were the only factors that significantly influenced survival. There was no difference in the survival of patients with proximally situated tumours compared to those with distally located tumours. Wide variations in clinical practice were seen between different surgeons. Consequently, a multidisciplinary team designed to manage all patients with oesophagogastric cancer according to nationally agreed protocols has been established in our hospital. Earlier diagnosis of these tumours is to be encouraged, even if this necessitates the more liberal use of endoscopy in the evaluation of young patients with persistent foregut symptoms.

Molecular failure of apoptosis: inappropriate cell survival and mutagenesis?

Since cell death by apoptosis is achieved through complex interactions between numerous molecular components, cells may fail to die when stimulated because of molecular abnormalities in the apoptosis pathway or in its control mechanisms. Such inappropriate cell survival is well established when apoptosis is suppressed by elevated expression of bcl-2, at least for some cell types. Many cells undergo apoptosis at moderate levels of DNA damage and suppression of such apoptosis might be expected to increase the rate of mutation because of the persistence of cells with damaged DNA. We and others have now confirmed this prediction in bcl-2 transfected cells. Suppression of the apoptosis pathway can only lead to inappropriate cell survival if it relates to events before the cell becomes committed to die. We have analyzed this question for agents that inhibit the caspases, the site-specific proteases which form the biochemical core of the process of apoptosis. We have shown that inhibition of certain caspases does lead to the survival of Jurkat human T-cells induced to undergo Fas-mediated apoptosis.