Most of the neuroendocrine tumours produce and secrete a large number of peptide hormones and amines. Each of these substances cause a specific clinical syndrome: carcinoid, Zollinger-Ellison, hyperglycaemic, glucagonoma and WDHA syndrome. Specific markers for these syndromes are basal and/or stimulated levels of: urinary-5-HIAA, serum or plasma gastrin, insulin, glucagon, and VIP, respectively. About 1/3 of neuroendocrine tumours belong to the so-called "non-functioning" tumours. Therefore, general markers such as chromogranin A, pancreatic polypeptide, serum neuronspecific enolase and subunit of glycoprotein hormones have been used for screening purposes in patients without distinct clinical hormone related syndromes. Among these general tumour markers chromogranin A, although its precise function is not yet established, has been shown to be a very sensitive and specific serum marker for various types of neuroendocrine tumours. This is because it may also be increased in many cases of less well differentiated tumours of neuroendocrine origin that do not secrete known hormones. Then chromogranin A is considered the best general neuroendocrine serum or plasma marker available at the moment and is increased in 50-100% of patients with various neuroendocrine tumours. Chromogranin A serum or plasma levels reflect tumour load and may be an independent marker of prognosis in patients with midgut carcinoids.
Wilson's disease is an autosomal, recessive-inherited disorder of impaired biliary copper excretion that results in the accumulation of copper in various organs including the liver, the cornea and the brain. The Wilson's disease gene on chromosome 13 codes for a copper transporting P-type ATPase-ATP7B. More than 60 mutations of this gene have been described. The diagnosis of Wilson's disease is based on clinical findings and laboratory abnormalities and can be made if two of the following symptoms are present: Kayser-Fleischer rings; topical neurologic symptoms; and low serum ceruloplasmin levels. In less typical cases diagnosis requires various other tests of copper metabolism. Effective medical treatment with copper chelators (D-penicillamine, trientine) or zinc results in symptomatic improvement and normal life expectancy. Orthotopic liver transplantation is indicated in advanced cases with hepatic decompensation or in patients with fulminant Wilson's disease.
Multiple endocrine neoplasia type 1 has intrigued clinicians since its description because of its rarity and complex presentation of tumours in disparate endocrine organs. Its unpredictable course has made the development of strategies for clinical management difficult The frequently indolent course in some family members, punctuated by lethal, aggressively malignant disease in others, has been frustrating as we strive to develop low-morbidity schemes for the prevention of the lethal manifestations of the syndrome. The recent description of the genetic abnormality responsible for the disease in many, if not all, families, will be of great assistance, even if it only allows the cessation of diagnostic testing for kindred members who are found to not carry the genetic abnormality In fact, there is great promise in this discovery, as it may shed light on significant aspects of neuroendocrine oncogenesis. In spite of this, the clinical management strategies for these families will require further focused attention, in order to develop rational, prospective studies to answer the many questions that remain.
Neuroendocrine tumours of the gastro-entero-pancreatic tract are an uncommon clinical entity and are believed to arise from the endocrine cells of the gastrointestinal tract. Somatostatin receptor imaging is a diagnostic tool which allows visualization of somatostatin receptor bearing tumours. This scintigraphic procedure is performed with indium-111 labelled octreotide, a somatostatin analogue, chelated with diethylene triamine penta-acetic acid. Radionuclide imaging consists in detecting the biodistribution of somatostatin receptors, normally expressed on the cell surface of neuroendocrine gastro-entero-pancreatic tumours. To date, five types of this receptor have been cloned: indium-111-labelled-pentetreotide can visualize tumours expressing type 2 and 5 receptors. The results of our study, which involved 81 neuroendocrine gastro-entero-pancreatic tumour patients, confirm the superior sensitivity of somatostatin receptor imaging (61%) for primary tumour evaluation with respect to conventional imaging modalities such as computed tomography (40%) or ultrasound (28%). Scintigraphic findings in metastatic liver disease proved to have a sensitivity of 89% for somatostatin receptor imaging, versus 81% and 88% for computed tomography and ultrasound, respectively. In 23% of patients, lesions were found with somatostatin receptor imaging which had been missed using the other diagnostic modalities; in 26% of the patients the therapeutic approach was modified after somatostatin receptor imaging.
The recent recognition of the nature of gastric carcinoids and the elucidation of the biological events associated with enterochromaffin-like cell transformation has provided an opportunity to advance the understanding of this particular type of neuroendocrine tumour. The relationship between hypergastrinaemia present in low acid disease states and the development of gastric carcinoids has led to an appreciation of the role of gastrin as a growth mediator in the evolution of this type of neoplasia. In addition, evidence exists to support a genetic predisposition to this tumour type in individuals with Multiple Endocrine Neoplasia type 1 syndrome, and in an experimental model--the African rodent species, Mastomys. The recent development of an isolated pure enterochromaffin-like cell preparation has facilitated the elucidation of the molecular physiology of the naive enterochromaffin-like cell and, in addition, allowed the evaluation of the cellular events associated with enterochromaffin-like cell transformation from the naive state to the neoplastic phenotype. This synopsis seeks to present information relevant to both the animal model and the human disease state. The aim is to facilitate an appreciation of the regulatory mechanisms of the enterochromaffin-like cell and delineate the changes consequent to the development of the neoplastic phenotype.
BACKGROUND:Since 1994, the hypothesis of a potential causal relationship between vaccination against hepatitis B and multiple sclerosis (and other demyelinating diseases) was brought to the attention of the French health authority, and to public debate. In Italy, since 1991, vaccination against hepatitis B has been mandatory for newborns and 12-year-old children, and also recommended for high-risk groups.AIM:To re-evaluate the risk/benefit profile of the Italian strategy of hepatitis B vaccination.SUBJECTS:The study population is a hypothetical cohort of 100,000 newborns.METHODS:We present a simulation of the hepatitis B cases that could be prevented with the vaccination and of the potential excess of multiple sclerosis cases which would occur, assuming different odds ratios of multiple sclerosis among vaccinees, and by effecting the vaccination at different ages.RESULTS:In the cohort, we would expect 1,099 hepatitis B cases, that would be prevented with vaccination. Assuming that the highest odds ratio of 1.7 reported is true, the excess of "life-time" multiple sclerosis incidence would be 0.3% for 12-year-old subjects, and 2.9% for adults.CONCLUSIONS:On the basis of these data, our opinion is that the hepatitis B vaccination strategy presently adopted in Italy for newborns, teen-agers and high risk groups should not be modified.
Recent studies report that the radiolabelled synthetic somatostatin analogue, [111In-DTPA-DPhe1]octreotide, is useful for imaging carcinoid tumours and pancreatic endocrine tumours. At present, it is unclear whether this method is superior to conventional imaging studies (computed tomography, magnetic resonance imaging, ultrasound, angiography) and what its role should be, if any, in the management of these patients. The aim of this paper is to review five recent studies performed at the National Institutes of Health in patients with Zollinger-Ellison syndrome to define the role of somatostatin receptor scintigraphy. Patients were from a tertiary referral centre, all had Zollinger-Ellison syndrome. In Study n. 1: the sensitivity of somatostatin receptor scintigraphy was assessed compared to conventional studies in 80 patients. Study n. 2: the effect of somatostatin receptor scintigraphy on management was determined in 122 patients. Study n. 3: ability of somatostatin receptor scintigraphy and other conventional methods to distinguish small hepatic metastases (< 2 cm) from hepatic haemangiomas was assessed in 29 patients. Study n. 4: somatostatin receptor scintigraphy, magnetic resonance imaging and bone scanning were compared in 115 consecutive patients to detect bone metastases. Study n. 5: ability of somatostatin receptor scintigraphy to detect gastrinomas found at surgery in 35 patients and its effect on cure rate and determinants of detection of gastrinomas by somatostatin receptor scintigraphy were analysed. Briefly, results showed: Study n. 1: somatostatin receptor scintigraphy is the most sensitive modality for detection of primary or metastatic gastrinomas; Study n. 2: somatostatin receptor scintigraphy changes management in 47% of cases; Study n. 3: somatostatin receptor scintigraphy is the only method to distinguish small liver metastases from small haemangiomas; Study n. 4: somatostatin receptor scintigraphy and magnetic resonance imaging have higher sensitivity and predictive values for bone metastases than bone scanning; Study n. 5: somatostatin receptor scintigraphy misses 33% of gastrinomas found at surgery, primarily small duodenal tumours. Size is the important factor. The use of somatostatin receptor scintigraphy does not increase cure rate. In conclusion, Somatostatin receptor scintigraphy is now the imaging method of choice in patients with Zollinger-Ellison syndrome for preoperative primary tumour localization, detection of bone or liver metastases, and to distinguish small liver metastases from small hepatic haemangiomas. Its specificity appears to be high but has been poorly studied as has the use of it in combination with endoscopic ultrasound. Studies by others suggest these recommendations will apply to carcinoid tumours and other pancreatic endocrine tumours except insulinomas.
BACKGROUND:The susceptibility to coeliac disease is genetically determined by possession of certain HLA DQ alleles, together with a one or more non-HLA genes. The central role of the T-cell receptor in disease pathogenesis makes the T-cell receptor genes strong candidates as disease susceptibility genes, and previous studies had provided equivocal ambiguous results.METHODS:A pedigree based genetic linkage study was used to determine if any of the T-cell receptor genes have a role in the genetic aetiology of coeliac disease. Intragenic microsatellite markers were used to study T-cell receptor alpha, beta, and delta, while gamma was studied using two flanking microsatellites D7S484 and D7S629.RESULTS:Conventional linkage analysis was performed using the MLINK computer package. Model-free linkage analysis was performed using MFLINK. No evidence of linkage between coeliac disease and the T-cell receptor genes was found in these pedigrees.CONCLUSIONS:Mutations in the T-cell receptor genes are not implicated in the genetic aetiology of coeliac disease.
BACKGROUND AND AIM:Even if different Helicobacter species can colonise animal livers and induce hepatitis, there is no evidence that Helicobacter pylori can damage this organ and only a potential capacity of cytotoxic strains to increase transaminases in humans has been suggested. We have, therefore, carried out an immunohistochemical study on vacuolating cytotoxin in the hepatocytes of subjects with isolated hypertransaminasaemia.PATIENTS, METHODS AND RESULTS:Five male patients with isolated hypertransaminasaemia without signs of known causes of liver diseases were studied. Endoscopy demonstrated diffuse mucosal hyperaemia in 3 patients and duodenal ulcer in one. Histology revealed active chronic pangastritis in all. Helicobacter pylori was assessed by histology and culture and its cytotoxity, demonstrated by positive immunoblotting for both anti-CagA and VacA. Percutaneous liver biopsy showed minimal changes. Hepatic and gastric sections were tested either with autologous serum and rabbit antibody to VacA toxin. Immune reaction was revealed by immunoperoxidase. Both autologous sera and anti-VacA toxin antibody showed a reaction with a similar pattern which involved 60% of hepatocytes. Anti-VacA toxin showed a reaction to gastric epithelial cells and autologous sera to parietal cells in 4/5 patients. All patients received triple therapy and eradication of Helicobacter pylori was assessed by urea breath test. Serum transaminase levels 3 months after eradication, are still abnormal.CONCLUSIONS:Our immunohistochemical findings suggest that vacuolating cytotoxin could reach the hepatocytes of patients suffering from both isolated hypertransaminasaemia and infection by cytotoxic strains of Helicobacter pylori. Nevertheless, a clear relationship between these two condition remains uncertain.
Neuroendocrine tumours of the gastroenteropancreatic tract are growths originating either from the cells of the diffuse (neuro)endocrine system, such as gastric carcinoids and islet cell tumours, or from nerve structures, such as duodenal paragangliomas. A great deal of cellular and clinical information is available whereas data concerning the genetic and molecular basis of diffuse (neuro)endocrine system tumours of the gastroenteropancreatic tract are very few and fragmentary. The present paper reviews some genetic and molecular investigations of potential interest. As far as concerns the genetic background of diffuse (neuro)endocrine system tumours, the frequent loss of heterozygosity for the locus of Multiple Endocrine Neoplasia type 1 in tumour samples suggests a potential role of the Multiple Endocrine Neoplasia gene. With regard to the molecular background, no mutation of the p53 or retinoblastoma susceptibility (Rb) genes has been demonstrated. Useful data have been generated by in situ analysis of the proliferation activity of tumours.
BACKGROUND:The excessive accumulation of cholesterol absorbed from bile by the gallbladder impairs its contractility and favours gallstone formation. The total low plasma and high density lipoprotein cholesterol concentrations are associated with gallstone disease.AIMS:To investigate the effect of plasma lipoproteins on gallbladder cholesterol and phosphatidylcholine absorption from bile and to establish whether cholesterol absorption is Brefeldin A-sensitive.METHODS:Gallbladder mucosa lipid absorption rates were measured using: 1) in vitro isolated intra-arterially perfused pig gallbladder model with and without plasma lipoproteins perfusing the vascular tree; 2) human gallbladder fragments mounted in Ussing chambers with plasma lipoproteins at different concentrations in the serosal side; 3) pig gallbladder fragments mounted in Ussing chambers in the presence and absence of Brefeldin A.RESULTS:Total lipoproteins and high density lipoprotein significantly increased the release of biliary cholesterol and phosphatidylcholine in plasma and significantly decreased the tissue accumulation of cholesterol absorbed from bile. The scavenger effect of plasma lipoproteins on cholesterol absorbed from bile was concentration dependent. Brefeldin A did not influence gallbladder absorption of biliary cholesterol.CONCLUSIONS:Biliary cholesterol is absorbed by gallbladder mucosa via a Brefeldin-insensitive pathway and is removed by plasma lipoproteins.
A brief review is made of the use of high dose polyethylene glycol solution in the treatment of functional constipation and encopresis in children. Experience with low dose polyethylene glycol for the treatment of neurogenic constipation in children with severe brain damage is also reported. Treatment with polyethylene glycol caused a significant increase in bowel frequency and a decrease in gastrointestinal transit time. Side-effects, consisting of nausea, vomiting and irritability, have limited the use of this treatment in a few children.
