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Measurement of chromogranin A (CgA) plays a major role in the management of neuroendocrine tumors (NET); however, reliable assaying of CgA is made difficult by the rapid hydrolysis following its release into the bloodstream. This study was aimed at the assessment of two assays for CgA in NET patients. CgA was measured in 93 patients by means of an enzyme-linked immunosorbent assay (ELISA) and an immunoradiometric assay (IRMA). The specificity and sensitivity of CgA were evaluated in relation to tumor histology. The clinical accuracy of the two assays was evaluated by receiver-operating characteristic (ROC) curve analysis. Regression analysis demonstrated different immunoreactivity for CgA of the antibodies used in the two kits (r = 0.61). The two assays had different accuracy also in classifying patients according to their clinical condition (91% vs 64% specificity and 79% vs 79% sensitivity for the ELISA and IRMA assay, respectively) and tumor histology (81% vs 85% sensitivity for the ELISA and IRMA assays, respectively, in carcinoids; 92% vs 67% sensitivity for the ELISA and IRMA assays, respectively, in pancreatic islet cell tumors). The different clinical accuracy of the two assays was confirmed by the ROC analysis (AUC = 0.90 vs AUC = 0.87 for the ELISA and IRMA assays, respectively). In conclusion, because of the poor standardization of the commercially available measurement tools the clinical accuracy of CgA measurement depends on the assay used. This makes it difficult to compare CgA values measured with different kits and affects the clinical accuracy of the different assays for CgA.

Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by abdominal pain and changes in bowel habits, not sustained by structural changes. There is now consistent evidence indicating that IBS may be the adverse outcome of an acute episode of infectious gastroenteritis, the so-called postinfectious (PI) IBS. The infectious agents involved in the development of PI-IBS include pathogenic bacteria, parasites, and viruses. Abdominal pain and diarrhea are the most common symptoms of PI-IBS. Several studies identified a number of risk factors increasing the susceptibility for PI-IBS development. These include the virulence of the pathogen, the severity, and duration of the acute enteritis, younger age, female sex, and psychological disturbances. Several mucosal abnormalities in the colon or ileum of patients who develop PI-IBS have been described. These changes include increased mucosal permeability, an increased amount of intraepithelial lymphocytes, lamina propria T cells, and mast cells, as well as serotonin-containing enteroendocrine cells. The mediators released by these activated cells may evoke enteric nervous system responses, excite sensory afferent pathways, and induce visceral hyperalgesia. Little is known about the prognosis of PI-IBS, although it is likely better than that of nonspecific IBS. There is little evidence about a specific treatment for PI-IBS. Although probiotics and antibiotics may be promising in the prevention of PI-IBS, the efficacy of these treatments should be assessed in an ad hoc designed study.

We report a retrospective study on serum and cerebrospinal fluid (CSF) alpha-fetoprotein (AFP) and beta-human chorionic gonadotropin (betahCG) determination in a series of 30 patients bearing intracranial germ cell tumors. At diagnosis five patients had high serum and CSF AFP levels. No patient had positive serum AFP and negative CSF AFP or vice versa. Twelve of 30 patients had serum betahCG levels above 5 mlU/mL, eight had high betahCG only in CSF, and ten were completely negative. During treatment and follow-up both markers were accurate indicators of the response to therapy, decreasing rapidly and often becoming normal already after the first phase of treatment. We conclude that these two markers, and mostly betahCG, may be useful in the diagnosis and monitoring of the response to therapy of patients with intracranial germ cell tumors.