Paolo Bechi

Long-term ambulatory enterogastric reflux monitoring. Validation of a new fiberoptic technique.

A new technique for the long-term ambulatory detection of enterogastric and nonacid gastroesophageal reflux has been conceived, developed, and validated. It is based on the use of a fiberoptic sensor that utilizes the optical properties of bile.In vitro studies have shown good precision, good stability, sensitivity of 2.5 μmol/liter bilirubin concentration, as well as a useful working range of 2.5–100 μmol/liter bilirubin concentration.In vivo studies have been performed in 29 subjects. Simultaneous gastric aspirations have allowed a comparison of fiberoptic system measurements both with spectrophotometric analysis and bile acid concentrations of corresponding gastric juice samples. Linear correlations were shown between fiberoptic assessment and both spectrophotometric and bile acid concentration findings (P<0.01). Simultaneous assessment of reflux with the fiberoptic system and cholescintigraphy has shown a 92.9% concordance as regards the presence or absence of reflux. Present results imply that the fiberoptic system is an important tool for the understanding of the clinical relevance of enterogastric and nonacid gastroesophageal reflux.

Lymph node recovery from colorectal tumor specimens: recommendation for a minimum number of lymph nodes to be examined.

Lymph node involvement is the mostimportant prognostic factor for patients who have undergone radicalsurgery for colorectal carcinoma. An accurate examination of thesurgical specimens is mandatory for the correct assessment of the lymphnode status of the tumor. The risk of understaging is particularly highfor patients with tumors classified as Dukes B (TNM stage II). The aimof this study was to determine if a specified minimum number of lymphnodes examined per surgical specimen could have any effect on theprognosis of patients who had undergone radical surgery for Dukes Bcolorectal cancer. Between 1988 and 1995 a total of 140 patientsunderwent radical resection of Dukes B colorectal cancer by the samesurgeon (C.C.). The relation between clinicopathologic variables andsurvival was estimated using the Kaplan-Meier method. The Coxproportional hazard regression model was used to identify the variablesthat can independently influence survival. A median of 12 lymph nodes(range 3–38) was examined per tumor specimen. The 5-year survival rateof Dukes B patients who had had eight or fewer lymph nodes examinedafter surgery was 54.9%, whereas the survival rate for those who hadhad nine or more lymph nodes examined was 79.9% (p < 0.001). Cox regression analysis identified the number of lymph nodes asthe only independent prognostic factor (p = 0.01).Seventy patients with one to four metastatic lymph nodes (Dukes Cpatients) who had been operated on during the same period were includedin the survival analysis for comparison. The 5-year survival rate ofthe Dukes B patients with eight or fewer lymph nodes examined wassimilar to that of the 70 Dukes C patients (54.9% and 51.8%,respectively). Examination of eight or fewer lymph nodes in Dukes Bcolorectal patients may be considered a high risk factor for missingpositive lymph nodes in the surgical specimens. Our results suggestthat harvesting and examining a minimum of nine lymph nodes persurgical specimen may be sufficient for reliable staging of lymphnode-negative tumors.

Inducible Nitric Oxide Synthase Expression in Human Colorectal Cancer : Correlation with Tumor Angiogenesis

To investigate the potential involvement of the nitric oxide (NO) pathway in colorectal carcinogenesis, we correlated the expression and the activity of inducible nitric oxide synthase (iNOS) with the degree of tumor angiogenesis in human colorectal cancer. Tumor samples and adjacent normal mucosa were obtained from 46 surgical specimens. Immunohistochemical expression of iNOS, vascular endothelial growth factor (VEGF), and CD31 was analyzed on paraffin-embedded tissue sections. iNOS activity and cyclic GMP levels were assessed by specific biochemical assays. iNOS protein expression was determined by Western blot analysis. iNOS and VEGF mRNA levels were evaluated using Northern blot analysis. Both iNOS and VEGF expressions correlated significantly with intratumor microvessel density (r(s) = 0.31, P = 0.02 and r(s) = 0.67, P < 0.0001, respectively). A significant correlation was also found between iNOS and VEGF expression (P = 0.001). iNOS activity and cyclic GMP production were significantly higher in the cancer specimens than in the normal mucosa (P < 0.0001 and P < 0.0001, respectively), as well as in metastatic tumors than in nonmetastatic ones (P = 0.002 and P = 0.04, respectively). Western and Northern blot analyses confirmed the up-regulation of the iNOS protein and gene in the tumor specimens as compared with normal mucosa. NO seems to play a role in colorectal cancer growth by promoting tumor angiogenesis.

Inhibition of 5-lipoxygenase by MK886 augments the antitumor activity of celecoxib in human colon cancer cells

Cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LOX) are key enzymes involved in arachidonic acid metabolism. Their products, prostaglandins and leukotrienes, are involved in colorectal tumor development. We aimed at evaluating whether combined blocking of the COX-2 and 5-LOX pathways might have additive antitumor effects in colorectal cancer. The expression/activity of COX-2 and 5-LOX were assessed in 24 human colorectal cancer specimens. The effects of the COX-2 inhibitor celecoxib and the 5-LOX inhibitor MK886 on prostaglandin E2 and cysteinyl leukotriene production, tumor cell proliferation, cell apoptosis, and Bcl-2/Bax expression were evaluated in the Caco-2 and HT29 colon cancer cells. We also investigated the effect of the enzymatic inhibition on mitochondrial membrane depolarization, one of the most important mechanisms involved in ceramide-induced apoptosis. Up-regulation of the COX-2 and 5-LOX pathways was found in the tumor tissue in comparison with normal colon mucosa. Inhibition of either COX-2 or 5-LOX alone resulted in activation of the other pathway in colon cancer cells. Combined treatment with 10 μmol/L celecoxib and MK886 could prevent this activation and had additive effects on inhibiting tumor cell proliferation, inducing cell apoptosis, decreasing Bcl-2 expression, increasing Bax expression, and determining mitochondrial depolarization in comparison with treatment with either inhibitor alone. The administration of the ceramide synthase inhibitor fumonisin B1 could prevent some of these antineoplastic effects. In conclusion, our study showed that inhibition of 5-LOX by MK886 could augment the antitumor activity of celecoxib in human colorectal cancer. [Mol Cancer Ther 2006;5(11):2716–26]

Genomic and genetic alterations influence the progression of gastric cancer

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, although the incidence has gradually decreased in many Western countries. Two main gastric cancer histotypes, intestinal and diffuse, are recognised. Although most of the described genetic alterations have been observed in both types, different genetic pathways have been hypothesized. Genetic and epigenetic events, including 1q loss of heterozygosity (LOH), microsatellite instability and hypermethylation, have mostly been reported in intestinal-type gastric carcinoma and its precursor lesions, whereas 17p LOH, mutation or loss of E-cadherin are more often implicated in the development of diffuse-type gastric cancer. In this review, we summarize the sometimes contradictory findings regarding those markers which influence the progression of gastric adenocarcinoma.

Extracolonic polyps in familial polyposis coli and Gardner's syndrome

Endoscopy and biopsy of the upper gastrointestinal tract and terminal ileum were performed in 24 patients with familial polyposis or Gardners syndrome in order to further define the incidence of extracolonic adenomatous polyps. Polyps, usually multiple and small in size, were detected in the gastric fundus (12.5 percent), antrum (29.1 percent), duodenum (66.6 percent), and terminal ileum (41.7 percent). Histology showed hyperplasia of the fundic glands and cystic dilatation in the polyps of gastric fundus, and adenomas in several cases of antral (three patients) or duodenal polyps (14 patients). Polyps of the terminal ileum were either adenomas (five patients) or lymphoid aggregates. Patients with stigmata of Gardners syndrome, desmoids or mesenteric fibromatosis presented a major incidence of adenomas in the duodenum, but not in other parts of the digestive tract investigated. Subsequent checkup after an average of 33 months in ten patients revealed an increase of lesions only in the duodenum in two patients. These findings confirm that adenomatous polyps are not limited to the colon and rectum, as previously believed, but can affect the whole gastrointestinal tract. Periodic surveillance of mucosa seems to be indicated, especially for the duodenum, since degeneration of adenomas into carcinoma is possible

Expression of Estrogen Receptor β in Colon Cancer Progression

Colon cancer is the most frequent neoplasia of the intestine. This pathology is the third highest cause of death from cancer with 430,000 deaths globally per year. Estrogen has also been implicated in the development and progression of colon cancer. Also sex-specific differences have been suggested to be involved in the process. Previous studies have shown the estrogen β receptor to be the dominant receptor type in normal colonic tissue and its down-regulation along with the progression of colorectal cancer. The presence of estrogen receptors and products of estrogen-related genes in the colon suggests that estrogens have direct effects on the colonic tissue. However, the specific effect of estrogens on a normal colon and the role in the colon carcinogenesis are far from clear. The aim of this study is to analyze by real-time polymerase chain reaction, the relative quantitative expression of the estrogen receptors β, β1, β2, and β5 in colon adenocarcinomas and to compare this expression with the respective in normal tissues. Moreover, we evaluate a possible correlation between estrogens receptor expressions and disease stages. Normal tissues show estrogen receptor β expression greater than pathologic tissues and the estrogen receptor β result as most expressed in the lower disease stages.

Gastric histology and fasting bile reflux after partial gastrectomy

Abstract Forty-four randomized, partially gastrectomized subjects were studied to assess whether gastric histologie findings after partial gastrectomy were related to reflux. Gastric biopsy specimens (12) were taken at different distances from the anastomosis. Histologic findings were as follows: (a) hyperplastic changes of the foveolar epithelium and (b) loss of the chief and parietal gland cells with atrophy of gastric glands (chronic atrophic gastritis). Hyperplastic changes typical of the perianastomotic area gradually decreased with increasing distance from the anastomosis. Hyperplastic changes showed a greater prevalence in Billroth II than in Billroth I subjects (100% vs. 29.4%). No significant association was found between histologic findings and symptoms. Hourly bile acid quantity (fasting bile reflux) and concentration were determined in the gastric aspirates. Bile reflux was greater after Billroth II than after Billroth I (fasting bile reflux median values: 30.5 vs. 0.18 μmol/h, respectively). The same was true for bile acid concentration (mean bile acid concentration median values: 624.9 vs. 17.5 μmol/L, respectively). Moreover, Billroth I subjects with hyperplasia had a greater quantity and concentration of reflux than those without hyperplasia (fasting bile reflux and mean bile acid concentration median values: 2.6 vs. 0.8 μmol/h and 4.7 vs. 2.7 μmol/L, respectively). These findings show that bile reflux is correlated with hyperplastic changes of the foveolar epithelium, but prevalence and severity of atrophic gastritis were not related to reflux. Therefore, although we failed to show any relationship between chronic atrophic gastritis and reflux, foveolar hyperplasia was shown to be reflux related.

Tumor angiogenesis in lymph node-negative rectal cancer: correlation with clinicopathological parameters and prognosis.

AbstractBackground: Intratumoral microvessel density (MVD) could be used as a prognostic factor in colorectal cancer. We retrospectively analyzed the value of microvessel count in predicting the clinical outcome of stage I and II (Dukes A and B) rectal cancer patients. Methods: Eighty-four patients who had undergone curative resection of lymph node-negative rectal cancer were included. Tumor type and differentiation, the depth of local invasion, venous invasion, the character of the invasive margin, and the degree of lymphocytic infiltration were evaluated for each tumor specimen. Immunohistochemical staining for the CD31 endothelial antigen was performed to highlight the microvessels. Results: The median value of MVD was 45 microvessels. Low MVD (microvessels ≤45) was observed in 41 patients (48.8%), and high MVD (>45) was found in 43 (51.2%). The presence of conspicuous lymphocytic infiltration was significantly associated with increased vessel density. With uni- and multivariate survival analysis MVD did not show any prognostic significance. The character of the invasive margin was the only parameter with independent prognostic value. Conclusions: MVD does not seem to provide any additional prognostic information when compared with standard histopathological parameters in lymph node-negative rectal cancer. It is likely that the strong association between MVD and the presence of conspicuous lymphocytic infiltration may interfere with its predictive value.

Distribution of the vanilloid (capsaicin) receptor type 1 in the human stomach

Vanilloid receptor type 1 (TRPV1) is expressed in a capsaicin-sensitive and peptide-containing sub-population of primary sensory nerves that in the rat stomach seems involved in regulation of chlorhydropeptic secretion and gastroprotection. Our aim was to identify which cell types express TRPV1 in the human stomach in order to gain a better insight in the role of this receptor in the regulation of HCl secretion. Immunohistochemistry, by using three different commercially available anti-capsaicin antibodies, in situ hybridisation and Western blot analysis were performed on fragments surgically obtained from the gastric body on the large curvature. TRPV1 labelling was found in the parietal cells at the level of intra-cytoplasmatic granules matching mitochondrial features and distribution. Immunolabelled neurons and nerve fibres were also seen, the latter numerous in the submucosa and mucosa and often ending close to the parietal cells. TRPV1 presence was confirmed by Western blot analysis and in situ hybridisation. TRPV1 presence in nerve structures and parietal cells suggests the possibility of a combined effect of both neuronal and epithelial TRPV1 on chlorhydropeptic secretion. The presumed TRPV1 mitochondrial location inside parietal cells is in favour of the existence of a local pathway of auto-regulation of HCl secretion. Therefore, TRPV1 might modulate chlorhydropeptic secretion in the human stomach through more complex pathways than previously thought.