Diagnostic Accuracy of EndoFaster® and Narrow-Band Imaging Endoscopy in Patients with Impaired Gastric Acid Secretion: A Real-Time Prospective Study.

BACKGROUND: EndoFaster® analyzes gastric juice in real time during gastroscopy allowing the detection of hypo-achlorhydric conditions, like corpus atrophic gastritis. Narrow-band imaging (NBI) endoscopy allows to accurately detect and perform target biopsies in areas of intestinal metaplasia, a histological change often associated to corpus atrophic gastritis. AIMS: To compare the diagnostic accuracy of EndoFaster® with histological evaluation for corpus atrophic gastritis through high-resolution (HR) NBI targeted biopsies. METHODS: Prospective study on consecutive adult patients undergoing gastroscopy between April and November 2018. Patients in therapy with proton pump inhibitors, previous gastric surgery, and/or known gastric neoplasia were excluded. At the beginning of gastroscopy, gastric juice was aspirated and analyzed by EndoFaster® in 15 seconds. Endoscopists were blinded to the report of EndoFaster®. Evaluation of gastric mucosa in HR-white light was firstly performed, then with HR-NBI allowing to perform targeted biopsies on areas suspected for intestinal metaplasia; otherwise, biopsies were performed according to the updated Sydney System protocol and sent for histopathological evaluation. RESULTS: Overall, 124 patients were included [64% F; 56 (18-85) years]. Corpus atrophic gastritis was present in 41.9% of patients. EndoFaster® showed an accuracy for corpus atrophic gastritis diagnosis, compared to histopathological evaluation as gold standard, of 87.1% and a sensitivity, specificity, PPV, and NPV of 78.8%, 93.1%, 89.1%, and 85.9%, respectively. pH showed a positive correlation with the severity score of atrophy (r = 0.67, 95% CI: 0.73-0.81, and p < 0.0001). EndoFaster® allowed to diagnose corpus atrophic gastritis in 3.7% of patients negative to NBI (corpus atrophic gastritis without intestinal metaplasia). CONCLUSION: EndoFaster® seems a promising tool to diagnose corpus atrophic gastritis. The evaluation of hypo-achlorhydria during gastroscopy can address bioptic sampling in corpus atrophic gastritis patients without intestinal metaplasia.

Eczema and food allergy in an Italian pediatric cohort: no association with TLR-2 and TLR-4 polymorphisms.

Recent studies have indicated that Toll-like receptor polymorphisms or their impaired signalling, specifically TLR-2 and TLR-4, were correlated with a higher risk for allergy. The purpose of this study is to evaluate the associations of TRL-2 and TRL-4 single nucleotide polymorphisms (SNP) and atopic traits in a cohort of 159 Italian allergic children (102 affected by eczema and 57 by IgE-mediated food allergy) and 147 healthy controls recruited in Rome, Italy. DNA was isolated from the peripheral blood and TLR-2 R753Q/TLR-4 D299G polymorphisms were determined by TaqMan MGB probes using Real-Time PCR technique. In the control group, the TLR-2 polymorphism R753Q had a prevalence of 2.5% while the frequency of the TLR-4 D299G was 12%. None of the 159 allergic patients showed the R753Q SNP. By contrast, 7/57 patients with food allergy (12%) and 6/102 subjects with eczema (6%) carried the TLR-4 mutation. In our cohort, no evidence of correlation between TLR-2 or TLR-4 polymorphism and eczema and food allergy incidence and/or severity was found. Further studies are needed to clarify the possible role of TLR-2 and TLR-4 polymorphism in allergic disease, in Italian children.

Upper and lower gastrointestinal causes of iron deficiency anemia in elderly compared with adult outpatients.

AIM: In the elderly, prevalence of bleeding- and/or iron malabsorption-related gastrointestinal (GI) causes of iron deficiency anemia (IDA) has not been addressed yet. The aim of this study was to assess the occurrence of malabsorptive diseases and bleeding lesions of the upper and lower GI tract in early (65-74 year-old) and late (over 75 year-old) elderly group compared with adult (50-64 year-old) outpatients. METHODS: The study enrolled 136 consecutive adult (N.=31), early (N.=48) and late elderly (N.=57) IDA outpatients who were referred to the Gastroenterology Department for IDA evaluation and underwent gastroscopy/histology and colonoscopy. RESULTS: Bleeding lesions were significantly less frequent in adult patients than in elderly patients (29% vs. 49.5%, P=0.0252). The most common bleeding lesions were large hiatal hernia (14.7%) and colon cancer (12.5%). Iron malabsorption diseases (Hp-related pangastritis, atrophic body gastritis and celiac disease) were more frequent in the adult group than in the early elderly group (80.6% vs. 56.2%, P=0.0367). In elderly patients, the observed prevalence of bleeding and iron malabsorption IDA causes was similar, whereas in adult patients iron malabsoptive diseases were more frequently detected (P<0.0001). The occurrence of concomitant IDA causes was not different among the three age-groups. CONCLUSION: In the early and late elderly, almost half of GI IDA causes are related to bleeding lesions which are more frequently observed respect to the adult patients. Iron malabsorption diseases affect almost 60% of early and late elderly groups. As for adult patients, an accurate upper and lower endoscopical/histological evaluation diagnoses IDA causes in the vast majority of the elderly outpatients.

Vasoactive intestinal peptide receptor subtypes and signalling pathways involved in relaxation of human stomach.

Vasoactive intestinal peptide (VIP) relaxes smooth muscle by interacting with receptors coupled to cAMP- or cGMP-signalling pathways. Their relative contribution to human gastric relaxation is unknown. This study aimed at investigating, in terms of biological activity, receptor expression and related signalling pathways, the action of VIP separately on the human fundus and the antrum. VIP caused greater relaxation of smooth muscle cells (SMC) and strips of the antrum presenting on the former a higher efficacy and potency (ED(50): 0.53 +/- 0.17 nmol L(-1)) than on the fundus (ED(50): 3.4 +/- 1.4 nmol L(-1)). On both fundus and antrum strips, its effect was tetrodotoxin insentitive. Reverse transcriptase-polymerase chain reaction analysis showed the sole expression of VPAC2 and natriuretic peptide clearance receptors, with VPAC2 being more abundant in the antrum. Functional regional differences in receptor-related signalling pathways were found. Activation of the cAMP-pathway by forskolin or its inhibition by adenylate cyclase (2'5'-dideoxyadenosine) or kinase (Rp-cAMPs) inhibitors had more pronounced effects on antrum SMC. Activation of the cGMP-pathway by sodium nitroprusside or its inhibition by guanylate cyclase (LY83583) or kinase (KT5823) inhibitors had more effects on fundus SMC, on which a higher expression of endothelial nitric oxide synthase was found. In conclusion, regional differences in VIP action on human stomach are related to distinct myogenic properties of SMC of the antrum and the fundus.

Somatostatin receptor subtypes mediate contractility on human colonic smooth muscle cells.

This study demonstrates the expression of functional somatostatin receptor (sstr) subtypes in human circular and longitudinal colonic smooth muscle cells (SMC). Native somatostatin (SS) and sstr subtype-specific analogues were used to characterize the sstr subtypes present in both cell types by contraction/relaxation studies. Qualitative and quantitative mRNA analysis and immunohistochemistry of sstr subtypes were also carried out. sstr subtype 2 mRNA was expressed in circular SMC, and various levels of subtypes 1, 2 and 3 mRNA were expressed in longitudinal colonic SMC. Native SS and each subtype-specific analogue exerted a modest, but significant, contraction, although inhibition of carbachol-induced contraction (relaxation) was the main effect on SMC from both layers. CH-288, a sstr subtype 1-specific analogue, and octreotide, a sstr subtype 2-specific analogue, were the most effective relaxant analogues on longitudinal and circular SMC, respectively. sstr subtypes display a distinct expression pattern on human colonic SMC; on circular SMC, subtype 2 is the only sstr, whereas sstr subtypes 1, 2 and 3 are expressed on human SMC isolated from the longitudinal layer. The contractile effects of SS are mediated through sstr subtype 2 and sstr subtype 1 on circular and longitudinal human colonic SMC, respectively.

Atrophic body gastritis in patients with autoimmune thyroid disease: an underdiagnosed association.

BACKGROUND: Atrophic body gastritis (ABG) has never been histologically characterized in patients with autoimmune thyroid disease (AITD), and its prevalence may be substantially different from that previously assessed based on only indirect evidence. OBJECTIVE: To detect and characterize the presence of ABG in patients with AITD. METHODS: Sixty-two patients with AITD (5 men and 57 women), aged between 21 and 74 years, have been screened for the presence of ABG by assaying serum gastrin levels. Patients with hypergastrinemia underwent gastroscopy followed by the histological examination of multiple biopsy specimens. The diagnosis of ABG was based on hypergastrinemia and pentagastrin-resistent achlorhydria, confirmed by histological examination. RESULTS: Twenty-two (35%) of 62 patients had hypergastrinemia (mean +/- SEM gastrin level, 1070+/-288 pmol/L). The diagnosis of ABG has been histologically confirmed in all 22 patients, and the score of atrophy was moderate to severe. In group A (patients aged 20-40 years; n = 21), 6 patients (29%) had ABG, compared with 11 patients (37%) in group B (patients aged 41-60 years; n = 30) and 5 patients (45%) in group C (patients aged 61-80 years; n = 11). Antiparietal cell antibodies were detected in only 68% (15/22) of patients with ABG. Anemia was observed in 82% (18/ 22) of patients with AITD and ABG but only in 22% (9/40) of patients without ABG (P<.0001). CONCLUSIONS: In the patients with AITD studied, about one third had ABG, which was diagnosed also in young patients; the measurement of gastrin levels represented the most reliable tool in the diagnosis of ABG; and the presence of anemia, even microcytic, was suggestive of undiagnosed ABG.

Application of clinical indexes in ulcerative colitis patients in regular follow-up visit: correlation with endoscopic 'mucosal healing' and implication for management. Preliminary results.

OBJECTIVE: Ulcerative Colitis (UC) is a chronic inflammatory disease of the colon of unknown etiology. Several clinical indexes have been proposed for UC disease activity evaluation, but none have been properly validated. Moreover, the reference parameter for the scores and their prognostic value is not clear. Mucosal healing has been recently proposed as an important end-point. Aim of the present study was to evaluate the correlation of four clinical indexes with objective diagnostic tools for UC evaluation, the discriminative ability in identifying patients with endoscopic mucosal healing, and to analyze the possible prognostic indication for disease course in 1 year of follow-up. PATIENTS AND METHODS: We analyzed data of 75 patients recorded in regular follow-up visit in IBD clinic at S. Andrea Hospital, Rome, between 2007-2011. We recorded clinical data and lab tests at the time of the visit, and endoscopic/histological reports performed within 1 month. Clinical indexes (Seo' activity index, Simple Clinical Colitis Activity Index, partial Mayo score and Endoscopic-Clinical Correlation Index) were calculated and correlation to endoscopic and histologic activity, and to C-reactive protein increment, was assessed by mean of Spearman's rank correlation. Discriminative ability of the indexes for patients with and without endoscopic mucosal healing was tested by calculation of area under ROC curve (AUC). Patients with low and high clinical scores were compared for number of flares and increment of therapy during 1 year of follow-up. RESULTS: Clinical indexes had a good correlation with endoscopic activity (mean r = 0.73 ± 0.06), a fair correlation with CRP-increment (mean r = 0.55 ± 0.01) and a poor one with histologic activity (mean r = 0.35 ± 0.01). The discriminatory ability of the indexes for endoscopic mucosal healing was good for all the indexes (mean AUC = 0.87 ± 0.05). Patients with high clinical score had more flares and required more frequently increase of therapy at 1 year of follow up compared with patients with low score. CONCLUSIONS: Clinical indexes have a good correlation with endoscopic activity and can discriminate patients with and without mucosal healing. Patients with low and high score have different risk of disease flare and of need to increase therapy at 1 year. Clinical indexes may represent a useful tool for disease assessment in clinical practice in UC outpatients with mild-moderate disease.

Cutaneous manifestations and gastrointestinal disorders: Report of two emblematic cases.

Gastrointestinal (GI) diseases, such as inflammatory bowel diseases (IBD), can manifest themselves with intestinal and extra-intestinal symptoms. Among the latter, cutaneous manifestations, such as pyoderma gangraenosum (PG) and metastatic Crohn's disease (MCD), represent a possible onset of IBD, with or without simultaneous bowel alterations. In such cases, intestinal and skin lesions are supported by the same immune-mediated mechanism. We hereby report two cases of patients with skin manifestations together with signs and symptoms suggestive of IBD. IBD and some skin lesions arise from the same immune-mediated mechanism. A multidisciplinary approach to these immune-mediated diseases is needed for an early and correct diagnosis, which in turn may lead to the use of the right drug avoiding useless treatment.

The antral mucosa as a new site for endocrine tumors in multiple endocrine neoplasia type 1 and Zollinger-Ellison syndromes.

Carcinoid tumors were identified in the antro-pyloric mucosa of four patients with multiple endocrine neoplasia type 1 (MEN-1)/Zollinger-Ellison syndrome, accounting for 8.7% of 46 patients with this condition examined by endoscopy and histology. In contrast, no tumors were found in the antral biopsies from 124 cases of sporadic Zollinger-Ellison syndrome (P < 0.001), indicating a prominent role for the MEN-1 gene defects in tumor development. Immunohistochemically the tumors did not express the hormones produced by antral endocrine cells (gastrin, somatostatin, serotonin). In contrast, two of them were diffusely immunoreactive for the isoform 2 of the vesicular monoamine transporter (VMAT-2), a marker specific for the gastric nonantral enterochromaffin-like (ECL) cells. In one of these patients a second antral VMAT-2-positive carcinoid was seen 21 months after the first diagnosis. The other two antral carcinoids were unreactive for VMAT-2. Multiple ECL cell tumors were found in the gastric body-fundus mucosa of the two patients with VMAT-2-positive, but not in those with VMAT-2-negative, antral carcinoids. In one case, the former tumors were diagnosed 22 months after the detection of the antral tumor. We conclude that the antral mucosa is an additional tissue that may harbor endocrine tumors in MEN-1 syndrome. These tumors did not express the phenotype of normal antral endocrine cells and, in at least two cases, were identified as ectopic ECL cell carcinoids.

Prevalence and causes of hypergastrinemia in primary hyperparathyroidism: a prospective study.

Gastrin levels have been reported to be often increased in patients with primary hyperparathyroidism (PHPT) considered to be caused by hypercalcemia. To determine the prevalence of increased basal gastrin and to investigate its causes, 52 consecutive patients with PHPT were studied prospectively, undergoing a clinical, biochemical, and gastric morphofunctional assessment before any parathyroid surgical procedure. This included evaluation of basal and secretin-stimulated gastrin, basal and pentagastrin-stimulated gastric acid secretion, upper gastrointestinal endoscopy, with histological evaluation for gastritis and Helicobacter pylori infection. Twenty of the 52 PHPT patients (38.5%) had increased fasting gastrin. Further investigation allowed us to clearly demonstrate the causes of hypergastrinemia in 16 of these 20 patients. In 7 of 20 (35%), hypergastrinemia was caused by gastric fundus atrophy; in 3 patients (15%), Zollinger-Ellison syndrome with Multiple Endocrine Neoplasia type I was diagnosed; whereas in another 20% of patients, mild hypergastrinemia was ascribed to Helicobacter pylori gastritis. Finally, in 2 patients, additional clinical history revealed an occasional use of the gastric antisecretory drug omeprazole a few days before the serum gastrin determination. This study shows that the hypercalcemic status per se is not sufficient to produce an increase in fasting gastrin levels. Furthermore, gastric fundus atrophy, and not gastrinoma, is the major cause of relevant (>160 pg/mL) hypergastrinemia.

Does the widespread use of proton pump inhibitors mask, complicate and/or delay the diagnosis of Zollinger-Ellison syndrome?

BACKGROUND: Proton pump inhibitors are potent acid suppressants which, at normal doses, can result in hypergastrinaemia in patients with idiopathic oesophageal reflux disease and in the control of symptoms in most patients with gastrinomas. Therefore, their use could delay or mask the diagnosis of gastrinoma. AIM: To investigate whether the widespread use of proton pump inhibitors masks or complicates the diagnosis of gastrinoma. SUBJECTS AND METHODS: Data from two centres with different referral criteria for suspected gastrinomas were analysed (Gastroenterology Unit, Rome, Italy and National Institutes of Health, Bethesda, MD, USA). The number of referrals and the number of new patients with gastrinoma diagnosed in the years prior to the widespread use of proton pump inhibitors (1986-1992) were compared with the numbers since proton pump inhibitors became widely available (1993-1998). RESULTS: The decrease in referral rate (P=0.0009) and the decrease in the annual rate of gastrinoma diagnosis (P=0.0020) at both centres correlated with the increased use of proton pump inhibitors. At the Italian centre, there was a 62% decrease in annual referrals (P < 0.0001) in the post-proton pump inhibitor period, relative to the pre-proton pump inhibitor period, whereas there was an increase in the rate of referral of other gastrointestinal endocrine tumours. The number of new cases of gastrinoma diagnosed decreased by 40%. At the US centre, the referral rate decreased by 28% (P=0.024) in the post-proton pump inhibitor period. There was also a 43% decrease in the number of new cases diagnosed annually in the post-proton pump inhibitor period (P=0.0012). There was a 2.6-fold increase in the post-proton pump inhibitor period in the percentage of referrals with a false diagnosis of gastrinoma as the cause of hypergastrinaemia (P=0.0040). CONCLUSIONS: In both referral centres, less patients have been referred with a possible diagnosis of gastrinoma and fewer new patients with gastrinoma have been diagnosed since proton pump inhibitors became widely available. These data support the conclusion that, since proton pump inhibitors have been released, the diagnosis of gastrinoma has been masked and will probably be delayed, with the result that patients with gastrinoma will be diagnosed at more advanced stages in their disease course.

p27: a potential main inhibitor of cell proliferation in digestive endocrine tumors but not a marker of benign behavior.

The immunohistochemical expression of the inhibitors of cyclin-dependent kinases p21 and p27 was investigated in 109 endocrine tumors of the pancreas and gastrointestinal tract and compared with that of Ki67 and p53. p21 was found to be scarcely expressed without significant differences between benign and malignant or between differentiated and undifferentiated tumors. This suggests no relationship between changes in p21 levels and clinical behavior in these endocrine tumors. p27 was found to be highly expressed in differentiated neoplasms and proved to be inversely related to Ki67 labeling (P =.02), which was usually low. These data indicate that p27 may have an important inhibiting role on the low proliferation rate of the tumors. Moreover, the protein may have a role in the resistance of differentiated endocrine tumors to chemotherapeutic agents. p27 high-expressor neoplasms were frequent in either benign (70.6%) or malignant (81.4%) differentiated tumors, thus not allowing the use of this protein for the differential diagnosis of malignant neoplasms as suggested for endocrine tumors of parathyroid and pituitary. Poorly differentiated endocrine carcinomas, which differred from the differentiated tumors for their very high Ki67 levels and frequent p53 expression, showed low or absent p21 and p27 in most cases. Classical midgut carcinoids were characterized by a sharp discrepancy between malignant behavior and very bland proliferative pattern, with Ki67 and p27 expressions similar to that of benign tumors.

Sampling strategies for analysis of enterochromaffin-like cell changes in Zollinger-Ellison syndrome.

To investigate the optimum number of biopsy specimens to be obtained for enterochromaffin-like (ECL) cell monitoring in hypergastrinemic patients and ECL cell regional variations potentially influencing the results, qualitative ECL cell changes were assessed in 149 patients with Zollinger-Ellison syndrome using jumbo biopsy specimens and a systematic sampling procedure of 4 areas each from the lesser or greater curvature of the gastric body. Of 1,176 specimens examined, 1,101 were adequate. The correlation was excellent between different sites within the greater or lesser curvature. In contrast, a normal ECL cell pattern was more frequent in the lesser curvature, whereas linear hyperplasia was more frequent in the greater curvature. Dysplastic lesions and carcinoid tumors in endoscopically unremarkable mucosa were detected in 3.4% and 1.2% of biopsy specimens, respectively, and were equally distributed between the lesser and greater curvature. Their chances of being diagnosed were related to the number of specimens examined. Extensive sampling of both the lesser and greater curvature is recommended for early diagnosis of dysplastic and/or carcinoid lesions in patients at risk. In contrast, limited sampling in the greater curvature seems to be adequate in patients with no risk for carcinoid development.

Morphometry of gastric endocrine cells in hypergastrinemic patients treated with the somatostatin analogue octreotide.

The aim of the study was to evaluate whether treatment with 200 micrograms/d of the somatostatin analogue octreotide (SMS 201-995) for three months can influence the trophic action exerted by hypergastrinemia on endocrine cells of the oxyntic mucosa, a condition potentially leading to hyperplasia and carcinoid tumors. Endocrine cells were morphometrically investigated in Grimelius silver stained sections of endoscopic biopsies of oxyntic mucosa collected from 13 hypergastrinemic patients with Zollinger-Ellison syndrome (ZES) (n = 5), antral G cell hyperfunction (AGCH) (n = 4) and atrophic gastritis type A (AG-A) (n = 4) before and after 3 months treatment and 3 months after drug discontinuance. The treatment induced a reduction of the volume density (P < 0.015), profile cross sectional area (P < 0.05) and number of cell profiles per unit area (P < 0.015) of argyrophil cells. A rebound of all these parameters was observed 3 months after drug withdrawal with values usually exceeding those at the entry, except in cases of AG-A. The patients' plasma gastrin concentrations presented similar variations showing a significant relation with all morphometric parameters of argyrophil cells. Also, the cell content in alpha subunit of human chorionic gonadotropin was related to the plasma gastrin levels, a finding confirming the close gastrin dependence of the expression of this protein by oxyntic endocrine cells. No significant changes were observed in mucosal somatostatin D cells. These results indicate that variations in circulating gastrin levels are the most likely factor responsible for the hypotrophic effect of octreotide on oxyntic argyrophil cells (mostly corresponding to the ECL cells) of hypergastrinemic patients.

Atrophic body gastritis patients with enterochromaffin-like cell dysplasia are at increased risk for the development of type I gastric carcinoid.

BACKGROUND/AIMS: In the presence of atrophic body gastritis, gastric carcinoid develops from gastric-body mucosa enterochromaffin-like cells. Few data exist on the prevalence of enterochromaffin-like dysplastic lesions in atrophic body gastritis patients and their presumed risk of evolution to carcinoid has never been assessed prospectively in humans. The aim of the present study was to investigate the prevalence and incidence of dysplastic and neoplastic enterochromaffin-like cell lesions in a consecutive series of patients with atrophic body gastritis. METHODS: A total of 130 atrophic body gastritis patients at diagnosis and 96 atrophic body gastritis patients at follow-up (median 30 months) underwent gastroscopy with multiple biopsies and fasting gastrinaemia evaluation. In patients with enterochromaffin-like cell dysplasia, a more detailed bioptic sampling at follow-up was performed. RESULTS: Of the 130 atrophic body gastritis patients, only one (0.7%) had a gastric carcinoid polyp, whereas enterochromaffin-like cell dysplasia was found in five patients (3.8%). At follow-up only one out of the 96 atrophic body gastritis patients (1%) was diagnosed as having a carcinoid polyp at 41 months. Enterochromaffin-like cell dysplasia was present in four additional patients (4.2%). Two atrophic body gastritis pernicious anaemia patients with enterochromaffin-like cell dysplasia developed a gastric carcinoid in the follow-up. Among nine atrophic body gastritis patients with enterochromaffin-like cell dysplasia, the incidence of carcinoid tumour was 22% compared to 1.1% of atrophic body gastritis patients without dysplasia (odds ratio: 26.00; 95% confidence interval: 2.089-323.52). During the follow-up, fasting gastrin levels increased significantly only in atrophic body gastritis patients with enterochromaffin-like cell dysplasia (mean 677.4 +/- 66.1 vs 1112.2 +/- 185.6; P = 0.0287). CONCLUSION: This study provides the first clinical evidence that, in hypergastrinaemic atrophic body gastritis patients, enterochromaffin-like cell dysplasia carries a markedly increased risk for development of type I gastric carcinoid. This suggests that a more detailed endoscopic/bioptic procedure in this subgroup of atrophic body gastritis patients is able to detect gastric carcinoid at an early stage.

Molecular insights into gastrointestinal neuroendocrine tumours: importance and recent advances.

A subset of gastrointestinal neuroendocrine tumours (carcinoids and pancreatic endocrine tumours) show aggressive growth. Early identification of this subset is essential for management; however, clinical, laboratory and histologic features frequently fail to achieve this. Currently, there is an increased understanding of the molecular pathogenesis/changes in neuroendocrine tumours and this may identify important prognostic factors and possibly, new treatments. Recent findings and progress in this area are briefly reviewed in this article.

Somatostatin receptor subtypes: basic pharmacology and tissue distribution.

The heptahelical receptor superfamily constitutes the largest single family of transmembrane-signalling molecules that regulate a wide range of physiological processes. The five somatostatin receptors represent a distinct subgroup of this seven transmembrane receptor superfamily. They range in size from 356 to 391 amino acids with 39-57% protein identity between the subtypes with 100 residues strictly conserved among the somatostatin receptor sequences. A high grade of mRNA homology exists in somatostatin receptor subtypes cloned from different species. Following somatostatin receptor binding and functional activity studies, two alternative models of ligand-binding interaction have been hypothesised. One relies on the presence of a binding pocket within the receptor structure constituted by specific amino acids residues, the other denies the presence of such binding structures and suggests that it is the interaction of agonists with specific extracellular and/or transmembrane domains that determine stable receptor structure conformation. Somatostatin receptors, as, indeed, all G-protein-coupled receptors are able to regulate their responsiveness to agonist exposure. This agonist-specific regulation includes three main events, namely, desensitisation, receptor internalisation and receptor degradation. The cell expression of somatostatin receptor subtypes, at the mRNA level, has been characterised in rodent and in human organs with multiple subtype expression in brain and peripheral tissues.

Unlabelled somatostatin analogues in treatment of digestive endocrine tumours.

Somatostatin analogues are considered first-line therapy in patients with digestive endocrine tumours. Indeed, several studies have investigated their efficacy in the control of specific symptoms and in the decrease of tumour markers. However, randomised controlled trials are needed in order to better define their role in non functioning tumours and their effect on tumour growth, which have seldom been assessed. Several new drugs have been developed over the last few years such as, for example, new long-acting formulations, universal analogues binding to all five somatostatin receptors subtypes, and cytotoxic analogues, all of which offer a promising therapeutic tool in the near future, even if further studies are needed to determine their efficacy and safety in man.

Co-existence of hyperparathyroidism, hypergastrinaemia and multiple gastric carcinoids is not always due to incomplete expression of the MEN-1 syndrome.

Until recently, the association of primary hyperparathyroidism and gastric carcinoid, with or without hypergastrinaemia, had been considered an incomplete form of multiple endocrine neoplasia type 1. This is because it seemed unlikely that the rare joint appearance of these diseases could occur only by chance. It is now possible to evaluate the pathogenetic involvement of the multiple endocrine neoplasia type 1 gene in many, apparently sporadic, clinical conditions. This is a case report of a female mimicking multiple endocrine neoplasia type 1 due to the presence of hyperparathyroidism, gastric carcinoid, and hypergastrinaemia. However, involvement of the MEN-1 gene (exons 2-10) was not detected, whereas hypergastrinaemia was attributed to a chronic atrophic gastritis.

Optimisation of isolation of richly pure and homogeneous primary human colonic smooth muscle cells.

BACKGROUND: Inherent properties of gastrointestinal smooth muscle can be assessed using isolated cell suspensions. Currently available isolation techniques, based on short 2-h enzymatic digestion, however, present the disadvantage of low cellular yield with brief viability. These features are an important limiting factor especially in studies in humans in which tissue may not be available daily and mixing of samples is not recommended. AIMS: To optimise the isolation procedure of cells from human colon to obtain a richly pure primary smooth muscle cell preparation. METHODS: Slices of circular muscle layer, obtained from surgical specimens of human colon, were incubated overnight in Dulbecco's modified eagle's medium supplemented with antibiotics, foetal bovine serum, an ATP-regenerating system and collagenase. On the following day, digested muscle strips were suspended in HEPES buffer, and spontaneously dissociated smooth muscle cells were harvested and used either immediately or maintained in suspension for up to 72 h. Cell yield, purity, viability, contractile responses, associated intracellular calcium signals and RNA and protein extraction were evaluated and compared to cell suspensions obtained with the current short digestion protocol. RESULTS AND CONCLUSION: The overnight isolation protocol offers the advantage of obtaining a pure, homogeneous, long-life viable cell suspension that maintains a fully differentiated smooth muscle phenotype unchanged for at least 72 h and that allows multiple functional/biochemical studies and efficient RNA extraction from a single human specimen.