Epidemiology of dental professional liability

The aim of this article is to collect data relating to dental professional liability in Italy and provide a common platform for discussions among clinicians, legal medicine practitioners, and experts in law. On the basis of two different dental-legal statistical samples (1,670 reports of legal dental experts and 320 civil court decisions) we analyzed the dental professional liability lawsuit in the areas of distribution of lawsuits among the different dental specialties, recurrence and type of errors, outcome of civil suits, parameters of compensation. Some ideas are also proposed for possible strategies in the management of clinical risk (prevention of errors) and court proceedings.

Multimodal rehabilitation for faecal incontinence: experience of an Italian centre devoted to faecal disorder rehabilitation

BACKGROUND

Sphincter exercises and biofeedback therapy have been used to treat faecal incontinence but results have been unpredictable and standards of treatment have not yet been established. The aim of this study was to retrospectively evaluate the effects of a new multimodal rehabilitation model on faecal incontinence.

METHODS

All of the rehabilitative procedures are guided by manometric data. Primary study outcome criteria were the determination of changes or deterioration in incontinence, failure to achieve full continence and/or presence of faecal urgency. The clinical outcome was designed according to the Jorge-Wexner incontinence score.

RESULTS

Between 1997 and 2001, one hundred forty-nine incontinent patients (85 F and 64 M; age range, 41-73 years; mean age, 60.6 years) underwent multimodal rehabilitation at our outpatient unit. The overall mean incontinence score had significantly improved after treatment ( p<0.001), and 58 patients (38.9%) were symptom free. No patient reported any deterioration in incontinence. Faecal urgency persisted in 23 patients (15.4%).

CONCLUSION

In conclusion, multimodal rehabilitation, using manometric study, can modify the incontinence score.

Up-regulation of cyclooxygenase 2 gene expression correlates with tumor angiogenesis in human colorectal cancer

BACKGROUND & AIMS

Recent studies have shown that cyclooxygenase (COX)-2 and its products, prostaglandins (PGs), may be involved in colorectal carcinogenesis. The aim of this study was to determine whether COX-2 expression and PGE(2) production correlate with microvessel density, vascular endothelial growth factor (VEGF) expression, and tumor metastasis in human colorectal cancer.

METHODS

Tumor samples and adjacent normal mucosa were obtained from 31 surgical specimens. Immunohistochemical expression of COX-2, VEGF, and CD31 was analyzed on paraffin-embedded tissue sections. COX-2 and COX-1 proteins were determined by Western blot analysis. COX-2 and VEGF messenger RNA expressions were evaluated using Northern blot analysis. PGE(2) production was determined by specific radioimmunoassay.

RESULTS

The immunohistochemical expressions of both COX-2 and VEGF were significantly correlated with microvessel density (P = 0.02 and P = 0.002, respectively). A significant correlation was found between COX-2 and VEGF expression (P = 0.004). Western analysis confirmed the up-regulation of COX-2 protein expression. COX-2 and VEGF genes were overexpressed in tumor specimens as compared with normal mucosa. PGE(2) levels were significantly higher in metastatic tumors than in nonmetastatic ones (P = 0.03).

CONCLUSIONS

COX-2 is related to tumor angiogenesis in colorectal cancer. It is likely that VEGF is one of the most important mediators of the COX-2 angiogenic pathway.

[Somatostatin receptors in non-endocrine tumours]

The study of the antiproliferative action of somatostatin (ss) is important not only to understand the regulation of neuroendocrine tumours that express receptors (sst), but also non-endocrine tumours which express these receptors. We previously demonstrated the presence of sst2 in a wide panel of cell lines from human neuroblastoma. Although hypotheses have been put forward that treatment with ss or its analogs may be beneficial in oncological patients, this does not appear to be the case in neuroblastoma; patients with high sst2 levels (who are therefore sensitive to ss treatment) have per se a relatively positive outcome. Therefore, adjuvant treatment with ss is not necessary. Viceversa, patients with a poor prognosis are essentially characterized by a low expression of sst2 (and therefore are insensitive to a therapy with ss). In these patients adjuvant treatment with ss might be indicated, but would have little chance of success. Although the majority of neuroendocrine tumours expresses sst2, pancreas and prostate cancer express sst1 but not sst2, and are therefore insensitive to octreotide treatment which binds preferentially to sst2. Tumours like colorectal carcinoma and breast cancer also express sst2 in their more favourable forms. However, the concentration of sst2 in colorectal cancer is similar, if not lower than that in the surrounding normal tissue. Therefore, the probability of successful adjuvant therapy with ss is relatively low. In breast cancer, it is possible that sensitivity to estrogens may have a positive influence on the expression of sst2. This might justify clinical trials with ss in breast cancer.

Marked variation of thymidylate synthase and folylpolyglutamate synthetase gene expression in human colorectal tumors

Patients with advanced colorectal cancer are currently being treated with 5-fluorouracil (5-FU)-based chemotherapy. A growing number of patients with resectable disease receive adjuvant therapy with 5-FU/levamisole (LEV) or 5-FU/folinic acid (LV). However, many patients still fail on these treatments, due to occurrence of natural or acquired tumor resistance. Among clinically relevant mechanisms of resistance to fluoropyrimidines, increased expression of thymidylate synthase (TS) has been emphasized. Another potentially relevant mechanism involves a decrease in folylpolyglutamate synthetase (FPGS) expression. To establish the value of these genes as prognostic factors and predictors of the outcome of 5-FU-based chemotherapy in colorectal cancer, we measured their expression in colorectal tumors from patients undergoing surgery and postoperative chemotherapy and compared it with that in normal colonic mucosa. This was done by a semi quantitative, nonradioisotopic polymerase chain reaction (PCR) method using beta-actin as an internal standard and expressed as a TS/beta-actin or a FPGS/beta-actin mRNA ratio. In tumor samples from 21 colorectal cancer patients, TS gene expression varied 118-fold. The median TS/beta-actin ratio was, in fact, 41.36 x 10(-3) (range 2.49 x 10(-3) to 294.54 x 10(-3)). Little variation in TS gene expression was observed in corresponding normal colic mucosa; the TS/beta-actin gene ratio was lower (median 26.16 x 10(-3); range 8.49 x 10(-3) to 69.49 x 10(-3)). Among tumor explants from 20 patients, FPGS expression varied over 161-fold. A similar marked variation was also observed in normal colonic mucosal samples (over 185-fold). Overall and disease-free survival data suggest an inverse association between the level of tumor TS and FPGS expression and clinical prognosis. The availability of this sensitive and accurate assay for gene expression should now make it possible to extend these laboratory/clinical correlations to larger populations.

Clinicopathologic characteristics and outcome indicators in node-negative gastric cancer

BACKGROUND AND OBJECTIVES

The relationship between the number of lymph nodes examined and the outcome in patients with node-negative (N(-)) gastric cancer was studied. We compared N(-) patients to those with nodal involvement (N(+)) to identify clinicopathologic characteristics of N(-) gastric cancer. Finally, we evaluated outcome indicators in this group of patients.

METHODS

Of 367 patients, 130 (35.4%) were N(-). These patients were stratified according to the main prognostic variables, to assess differences with N(+) cases. A statistical analysis using the Cox model was performed to estimate outcome indicators.

RESULTS

N(-) gastric carcinomas were significantly different from N(+) cases in terms of tumor depth and site, TNM stage, grading, residual disease, and vessel involvement. The overall 5-year survival rate was 72%. It was 82% in those patients with more than 15 nodes retrieved and 59% in the others. Serosal involvement, residual disease, and poor differentiation were independent prognostic factors.

CONCLUSIONS

The clinicopathologic factors and outcome of N(-) cases were similar to those of early gastric cancer. At least 15 examined nodes appears to be necessary to define a case as N(-). The prognostic value of D2 lymphadenectomy in N(-) patients suggests a biologic role of micrometastases.

Clinicopathologic findings and results of surgical treatment in cardiac adenocarcinoma

BACKGROUND AND OBJECTIVES

There is a great deal of controversy regarding the definition, classification, and staging of cardiac adenocarcinoma (CA). Recently, a shift from distal to proximal lesions has been documented in gastric cancer. We have stratified our cases of gastric cancer as CA, distal gastric cancer (DGC), and stump cancer (SC).

METHODS

Between 1986 and 1998, 450 patients with gastric cancer were operated on at our institute. The resectability rate was 81.6%. Of 367 patients, 48 were CA, 298 DGC, and 21 SC. These 3 groups were compared in terms of clinicopathologic factors and survival rates.

RESULTS

CA was significantly higher in male patients and showed a prevalence of the Lauren intestinal type. Regarding staging parameters, CA showed a higher rate of T3 tumors and of resection line involvement. Five-year survival rates were 23. 2% for CA, 45.0% for DGC, and 17.4% for SC.

CONCLUSIONS

A possible cause of the poor outcome of CA is presentation at a more advanced stage. CA was similar to SC as far as epidemiology, pathologic factors, and survival rates.

Clinicopathologic characteristics and outcome indicators in node-negative gastric cancer

BACKGROUND AND OBJECTIVES

The relationship between the number of lymph nodes examined and the outcome in patients with node-negative (N(-)) gastric cancer was studied. We compared N(-) patients to those with nodal involvement (N(+)) to identify clinicopathologic characteristics of N(-) gastric cancer. Finally, we evaluated outcome indicators in this group of patients.

METHODS

Of 367 patients, 130 (35.4%) were N(-). These patients were stratified according to the main prognostic variables, to assess differences with N(+) cases. A statistical analysis using the Cox model was performed to estimate outcome indicators.

RESULTS

N(-) gastric carcinomas were significantly different from N(+) cases in terms of tumor depth and site, TNM stage, grading, residual disease, and vessel involvement. The overall 5-year survival rate was 72%. It was 82% in those patients with more than 15 nodes retrieved and 59% in the others. Serosal involvement, residual disease, and poor differentiation were independent prognostic factors.

CONCLUSIONS

The clinicopathologic factors and outcome of N(-) cases were similar to those of early gastric cancer. At least 15 examined nodes appears to be necessary to define a case as N(-). The prognostic value of D2 lymphadenectomy in N(-) patients suggests a biologic role of micrometastases.

Clinicopathologic findings and results of surgical treatment in cardiac adenocarcinoma

BACKGROUND AND OBJECTIVES

There is a great deal of controversy regarding the definition, classification, and staging of cardiac adenocarcinoma (CA). Recently, a shift from distal to proximal lesions has been documented in gastric cancer. We have stratified our cases of gastric cancer as CA, distal gastric cancer (DGC), and stump cancer (SC).

METHODS

Between 1986 and 1998, 450 patients with gastric cancer were operated on at our institute. The resectability rate was 81.6%. Of 367 patients, 48 were CA, 298 DGC, and 21 SC. These 3 groups were compared in terms of clinicopathologic factors and survival rates.

RESULTS

CA was significantly higher in male patients and showed a prevalence of the Lauren intestinal type. Regarding staging parameters, CA showed a higher rate of T3 tumors and of resection line involvement. Five-year survival rates were 23. 2% for CA, 45.0% for DGC, and 17.4% for SC.

CONCLUSIONS

A possible cause of the poor outcome of CA is presentation at a more advanced stage. CA was similar to SC as far as epidemiology, pathologic factors, and survival rates.

Correlation between DNA content and p53 deletion in colorectal cancer

OBJECTIVE

To find out whether tumour DNA content correlates with allelic loss of p53 and other pathological features in primary colorectal carcinomas.

DESIGN

Ongoing prospective study.

SETTING

University hospital, Italy.

SUBJECTS

128 patients who had undergone radical resections for colorectal carcinoma.

INTERVENTIONS

Flow cytometric measurement of tumour DNA content and detection of allelic loss on the short arm of chromosome 17 by Southern blot (restriction fragment length polymorphism) analysis in fresh tumour specimens.

MAIN OUTCOME MEASURES

Correlation between DNA ploidy and deletion of p53, as well as between these two genetic events and clinicopathological variables.

RESULTS

Interpretable DNA histograms were obtained for 122 tumour specimens. Forty-three tumours (35%) were diploid and 79 (65%) aneuploid. The diploid tumours were significantly more common in the proximal colon (from the caecum to the splenic flexure) than in the distal colon (from the descending colon to the rectum) (p = 0.002). The allelic state on the short arm of chromosome 17 was evaluated in 80 heterozygous patients. Forty-four tumour specimens (55%) showed deletion of 17p. Allelic loss of p53 was significantly more common in the distal and rectal tumours than in the proximal ones (p < 0.0001). Aneuploidy was more common among those tumours which had shown deletion of p53 than in those that had not (p = 0.0008).

CONCLUSIONS

DNA aneuploidy was significantly associated with the deletion of the p53 gene. This suggests that the functional loss of p53 may favour the growth and establishment of an aneuploid cell population within tumours. Tumours of the proximal and distal colon differ in their genetic nature.

Short-term healing following the use of calcium sulfate as a grafting material for sinus augmentation: a clinical report

Because of the frequent lack of bone in the posterior maxilla, sinus augmentation has become a commonly practiced treatment modality. Many different materials have been used for augmenting the sinus, and the ideal graft is yet to be found. The present article reports the results of sinuses grafted with calcium sulfate in 2 patients. Bone biopsies were harvested 9 months after the augmentation procedure. In the first patient, 3 titanium threaded-cylinder implants were placed in the grafted area after 9 months, while in the second, 1 acid-etched, screw-shaped titanium implant was placed simultaneously with the graft. Light microscopic evaluation revealed new bone formation with ongoing remodeling and progressive lamellar maturation in the specimens. No remnants of the alloplastic material were detectable in any section, either within the bone or in the medullary tissue. When reevaluated at the uncovering procedure, the implants were radiographically and clinically judged to be osseointegrated. These observations suggest that, when used in the appropriate form and with the proper technique, calcium sulfate is a promising graft material for sinus augmentation, producing adequate quantity and quality of new bone for implant placement.

Pelvic floor dyssynergia and bimodal rehabilitation: results of combined pelviperineal kinesitherapy and biofeedback training

Dyschezia may be caused by pelvic floor dyssynergia, which takes place when a paradoxical contraction or a failure to relax the pelvic floor muscles occurs during attempts to defecate. The aim of our study was to set up a new bimodal rehabilitation programme for pelvic floor dyssynergia, which combined pelviperineal kinesitherapy and biofeedback, and to evaluate the results of this treatment. Thirty-five patients (age range: 28-64 years; mean age: 42.5 years) from the outpatient unit of the Clinica Chirurgica of the University of Florence, Italy, and an age-matched group of 10 healthy control subjects (age range: 31-59 years; mean age 45.7 years) with normal bowel habits and without any defecatory disorders, were studied. The 35 patients were symptomatic for dyschezia without slow colonic transit and had been diagnosed as being affected by pelvic floor dyssynergia. No evidence of any organic aetiology was present but all demonstrated both manometric and radiological evidence of inappropriate function of the pelvic floor. All of the patients underwent bimodal rehabilitation, using the combined training programme Clinical evaluation, computerized anorectal manometry and defecography were carried out 1 week before and 1 week after a completed course in bimodal rehabilitation. The control group underwent manometric and defecographic examination. Their results were compared with those of the 35 patients before and after training. After the programme, all 35 patients had a very significant increase in stool frequency (P < 0.001), while laxative and enema-induced bowel movements had become significantly less frequent (P < 0.001). After bimodal rehabilitation, computerized anorectal manometry showed some peculiar results. Resting anal canal pressure had increased but not significantly. Pre-programme values that indicated a shorter duration ("exhaustio") of maximal voluntary contraction than found in the controls had returned to normal values. The rectoanal inhibitory reflex (RAIR), with incomplete relaxation, which had been shorter than that of controls, became normal by the end of the rehabilitation. All RAIR parameters were significantly different especially when pre- and post-treatment values were compared (P < 0.001). No differences were found as regards rectal sensation parameters and rectal compliance between those before or after bimodal rehabilitation. Defecographic pretreatment X-ray films showed indentation of the puborectalis and poor anorectal angle (ARA) opening, at evacuation, with trapping barium of at 50%. After pelviperineal kinesitherapy and biofeedback training, the indentation had disappeared and the ARA had become significantly larger (P < 0.001) during evacuation. No differences were found after rehabilitation, when both were compared with those of controls. The pelvic floor descent was also significantly deeper (P < 0.001) than before the start of the programme. The bimodal rehabilitation technique can be considered a useful therapeutic option for functional dyschezia as shown by our clinical evaluations, manometric data and defecographic reports.

Character of the invasive margin in colorectal cancer: does it improve prognostic information of Dukes staging?

PURPOSE

The clinical significance and prognostic value of the histopathologic parameters used in both the Dukes and Jass classifications were evaluated to select those with an independent effect on survival after radical surgery for colorectal cancer.

METHODS

The depth of local spread (limited to the bowel wall or extended beyond it), the number of metastatic lymph nodes (none, 1-4, more than 4), the character of the invasive margin (pushing or infiltrating), and the presence or absence of conspicuous peritumoral lymphocytic infiltration were assessed in 235 patients who had undergone radical resection for colorectal cancer. The influence of these variables on survival was studied by univariate and multivariate analysis.

RESULTS

No significant difference in survival was found between patients with conspicuous peritumoral infiltrate and those without it; moreover, multivariate analysis failed to show any independent prognostic value for either lymphocytic infiltration or depth of local invasion. However, the character of the invasive margin and the number of metastatic lymph nodes were identified as the only variables with any independent importance on survival. Based on these data, a new prognostic model may be proposed; it uses the character of the infiltrative margin as a discriminating factor among patients within the lymph node-negative (Dukes A and B stages) and lymph node-positive (Dukes C1 and C2 subsets) groups. A good prognosis for Dukes A, B, and C1 patients was associated with pushing tumors; C1 and C2 patients with infiltrating tumors had a poor prognosis. On the whole, the new prognostic model has allowed for the placement of 59.6 percent of our patients into groups that provide a confident prognosis. The clinical outcome of Dukes A and B patients with infiltrating tumors is still uncertain.

CONCLUSIONS

The character of the invasive margin is an important prognostic factor in colorectal cancer. The association of this parameter with the traditional Dukes classification may provide additional useful prognostic information and aid in the selection of those patients who could most benefit from adjuvant therapy.

Anterior rectocele and anorectal dysfunction

The two types of anterior rectocele, "distension" of Type 1 rectocele (T1R) and "displacement" or Type 2 rectocele (T2R), have different anatomical, clinical and therapeutic profiles. The aim of this study was to assess anorectal function in patients with distension or displacement rectocele. Three groups of female patients and one group of healthy female subjects were studied. Both the 10 Group 1 subjects, who had been diagnosed as having T1R, and 10 Group 2 women who had been diagnosed as having T2R, were symptomatic for digital evacuation of the rectum. The 10 Group 3 females had complained of sever idiopathic constipation but had no defecatory disorders. The control group was made up to 10 healthy volunteers. All patients and controls underwent clinical evaluation, colonic transit time (CTT), computerized anorectal manometry (CAM), and defecography. Bowel movements and clinical evaluation were similar for both rectocele groups. In Group 1, CAM detected significantly higher anal pressure (P < 0.05) and more impaired rectoanal inhibitory reflex (RAIR) (P < 0.01) in comparison to the other patients and controls. In Group 2, the lowest anal pressure (P < 0.001) was noted but RAIR was normal. Defecographic results, at rest and during evacuation, showed a significantly (P < 0.001) higher anorectal angle and a more abnormal pelvic floor descent in Group 2 than in the other study groups and controls. Therefore, peculiar anorectal function was present in patients with anterior rectocele. A pelvic floor dyssynergia was noted in the distension rectocele group, while a fall of the pelvic floor was noted in the displacement rectocele group.

Nitric oxide synthase and VIP distribution in enteric nervous system in idiopathic chronic constipation

Idiopathic chronic constipation has been correlated to neural abnormalities that consist of a reduced number of myenteric plexus neurons and a decreased concentration of VIP-positive nerve fibers within the circular muscle. Recent studies hypothesized the involvement of nitric oxide in motility disorders of the human gut. To date, no information is available on nitric oxide involvement in idiopathic chronic constipation. The density of VIP- and nitric oxide-producing neurons was evaluated by immunocytochemistry using anti-VIP and anti-nitric oxide synthase antibodies in five patients with idiopathic chronic constipation. A low total neuron density was found at the myenteric plexus. The density of VIP-positive neurons was low while that of nitric oxide synthase-positive neurons was high at both plexuses. Our data confirm that idiopathic slow-transit chronic constipation is due to abnormal neurogenic factors. The presence of numerous nitric oxide synthase-positive neurons, all along the colon and at both plexuses, supports the hypothesis that an excessive production of nitric oxide may cause the persistent inhibition of contractions.

[Barrett esophagus. Diagnosis and treatment]

Columnar epithelial metaplasia of the distal esophagus (i.e. barrett's esophagus) is an acquired condition showing a prevalence of 4%. It is probably due to abnormal reparative processes of the esophageal squamous epithelium after gastroesophageal reflux damage. "Mixed" (both acid and biliary) reflux seems more relevant for the pathogenesis of Barrett's esophagus than acid reflux alone, as shown by recent studies with Bilitec 2000. Its diagnosis is not easy for the "cardiac", "fundic" or "indeterminate" types of columnar metaplasia and needs a close cooperation between the endoscopist and the pathologist. On the contrary, it is less difficult for the "distinctive" type of metaplasia. Barrett's esophagus surveillance represents a major challenge in the perspective of its malignant degeneration (adenocarcinoma risk 350 times greater than in the general population). Therapy of Barrett's esophagus includes drugs and surgical treatment. Among the drugs proton pump inhibitors such as Omeprazole seem, at the moment, the most effective for reflux control, as well as the Nissen-Rossetti operation seems the most widely accepted among the anti-reflux surgical procedures. The novelty concerning Barrett's esophagus therapy is represented by laser photoablation associated with proton pump inhibiting therapy. But the experience with this treatment is still at a preliminary stage. For Barrett's esophagus with severe dysplasia and/or adenocarcinoma and/or squamous cell carcinoma esophagectomy is needed with a different extent and approach, according to the extent of Barrett's esophagus and to the stage and site of the neoplastic changes.

Vasoactive intestinal polypeptide and nitric oxide synthase distribution in the enteric plexuses of the human colon: an histochemical study and quantitative analysis

Vasoactive intestinal polypeptide (VIP) and nitric oxide synthase (NOS) positive innervation patterns were immunohistochemically and statistically evaluated in the human colon. Specimens from the right colon (cecum, ascending and right transverse colon) and left colon (left transverse and descending colon) were obtained surgically, fixed either in paraformaldehyde or in Carnoy's or in Bouin's and paraffin embedded. Sections were stained with hematoxylin-eosin, toluidine blue, cresyl violet, neuron-specific enolase, anti-VIP, and anti-NOS. The same results were obtained regardless of the fixative used. Enolase-positive, VIP-positive, and NOS-positive cells were occasionally found within the circular muscle and interpreted as neurons. VIP-positive nerve fibers were evenly distributed within the circular muscle while NOS-positive ones were lacking in its inner portion. The left colon was richer in neurons than the right colon, at both plexuses. VIP- and NOS-positive neuron densities were higher at the left than at the right colon, whereas at all colonic levels VIP-positive neuron percentages at both plexuses and NOS-positive ones at the myenteric plexus were similar. At the submucous plexus the NOS-positive neuron percentage was lower than that of the VIP-positive one.

IN CONCLUSION

(a) the right colon contains a lower number of neurons and of VIP- and NOS-positive ones than the left colon, and (b) VIP- and NOS-positive fibers are differently distributed in the inner and outer portions of the circular muscle.

Effects of portacaval anastomosis on pancreatic islets of the rat

The pancreatic islets of rats with surgically constructed end-to-side portacaval anastomosis were studied immunocytochemically, morphometrically, and ultrastructurally, and the plasma levels of glucose, insulin, and glucagon determined. The results of the current study show that, four weeks after surgery, hypoglycemia, normal insulinemia, and hyperglucagonemia occur and that these hematologic changes are associated with immunocytochemical and ultrastructural signs of impairment of the secretory activity of islet B cells and normal secretion pattern of the remaining islet cell types. The causes and the meaning of the hematologic and islet cell changes are discussed, and the hypothesis has been drawn that they are primarily related to the functional deterioration of the liver, which follows the diversion of the portal blood in the systemic circulation.

Nitric oxide synthase immunoreactivity in the human ileocecal region

The nitric oxide (NO) producing neurons in the human ileocecal region (pre-junctional ileum, ileocecal and cecocolonic junctions, cecum and post-junctional colon) have been evaluated by immunocytochemistry. The percentage of NO synthase-positive neurons was higher at the myenteric plexus than at the submucous plexus, independently of the levels examined. The inner portion of the circular muscle layer, except at the ileal level, was devoid of immunoreactive nerve fibers. Data obtained suggest that neuronal-released NO at the ileocecal region has a greater role in the relaxation of the muscle coat, except for the inner circular muscle layer, than in the regulation of blood flow, absorptive and secretory processes.

Distribution of VIP-immunoreactive nerve cells and fibers in the human ileocecal region

VIP-containing nerve cells and fibers in the human ileocecal region (pre-junctional ileum, ileocecal and cecocolonic junctions, post-junctional cecum and colon) have been evaluated by immunocytochemistry. A high density of VIP-positive neurons and nerve fibers was found in all layers of the ileum. At all colonic levels examined and at both junctions, the percentage of VIP-containing cells was higher in the submucous plexus than in the myenteric plexus. At both junctions, the muscle wall was devoid of, and the myenteric plexus extremely poor in VIP-positive nerve fibers and cells. These data suggest that motility of these junctions is not--or only to a minor extent--regulated in man by VIP-containing nerves, at variance with other gut sphincteric areas.

Morphological evidence for a cecocolonic junction in man and functional implications

The region above, below and in front of the ileocecal valve opening has been studied in man using both light and electron microscopy. A cecocolonic junction, comprising the colonic basal portion of the ileocecal valve, could be demonstrated in man, due to the specific anatomy of the inner portion of the circular muscle. This muscle was arranged in anastomosing cords, richly innervated and enveloped by elastic fibers. Its smooth muscle cells were characterized by extremely wide sarcoplasmic cisternae and cell-to-cell junctions, numerous caveolae and large amounts of glycogen. Interstitial cells were rarely found. This junction might be considered responsible for (1) ileal flow accommodation, (2) colonic active movements and (3) ileocecal valve closing and opening.

GABAB receptor-mediated mechanisms in human intestine in vitro

The spontaneous motility of longitudinal muscle of human jejunum was recorded and the effect of gamma-aminobutyric acid-ergic (GABAergic) drugs was tested. GABA and (-)-baclofen (10(-6)-10(-4) M) dose dependently reduced the amplitude and frequency of the spontaneous contractions; muscimol and 3-aminopropanesulfonic acid (3 x 10(-5) M) were ineffective. The effect of 3 x 10(-5) M GABA was reduced by 3 x 10(-3) M 5-aminovaleric acid but not by 3 x 10(-5) M picrotoxin. The dose-response curve for GABA was shifted to the right by 3 x 10(-3) M 3-aminopropanesulfonic acid. Tetrodotoxin 3 x 10(-7) M prevented the GABAergic action, whereas various receptor antagonists tested did not affect it. GABAergic drugs did not influence the spontaneous motility of either circular or longitudinal muscles of human colon. It is suggested that GABAB receptor activation induces the inhibition of human jejunum longitudinal muscle motility by a neurogenic mechanism. The possible involvement of postganglionic cholinergic neurons is to be evaluated by other techniques.

Helicobacter pylori and luminal gastric pH. Relationships in nonulcer dyspepsia

The relationships between gastric pH and Helicobacter pylori infection were studied in 37 consecutive subjects affected with nonulcer dyspepsia. Each underwent esophagogastroduodenoscopy with multiple gastric biopsies for both H. pylori and histologic assessment, and 24-hr antral pH monitoring. H. pylori was harbored by 59.5% of the subjects with whole gastric spread of infection in all but one patient. Histologic gastritis was shown in 70.3% of the subjects. H. pylori was strongly associated with gastritis, both antral nonatrophic and multifocal atrophic. The ranges of 24-hr pH values were 1.3-6.9 in the H. pylori-positive and 1.2-6.8 in the H. pylori-negative group. Differences in pH values between the two groups were not significant. Moreover, the mean percent time duration of pH above 2, 4, and 6 did not significantly differ between the two groups. Therefore, this study has shown that chronic H. pylori infection is not related to luminal gastric pH.

Gastric cell proliferation kinetics and bile reflux after partial gastrectomy

Thirty-four randomized, partially gastrectomized subjects (12 with a Billroth II, 11 with a Billroth I, and 11 with a total biliary diversion reconstruction) were studied in order to assess the relationships between bile reflux, gastric histology, and cell proliferation kinetics. Bile acid quantity and concentration in the gastric aspirates progressively decreased from Billroth II to Billroth I to total biliary diversion (after which reflux was almost absent). Perianastomotic mucosa in Billroth II subjects showed the greatest degree of foveolar hyperplasia, and this decreased markedly with increasing distance from the anastomosis. Hyperplastic changes were less evident in Billroth I, and virtually absent in total biliary diversion subjects. The overall foveolar hyperplasia-like behavior of cell kinetic parameters (total pit cell number, labeled pit cell number, and labeling index) was shown. Moreover, subjects with mean bile acid concentration greater than 150 mumol/L had both a greater prevalence of foveolar hyperplasia and greater values of cell kinetic parameters than those with mean bile acid concentration less than or equal to 150 mumol/L. A superficialization of the proliferative compartment was also evident in the former group. These results show a close relationship between postgastrectomy bile reflux, foveolar hyperplasia, and cell kinetic parameters. Histologic and cell kinetic findings are probably the expression of gastric adaptation to chronic bile reflux exposure. Moreover, the type and entity of cell kinetic involvement and its relationship to foveolar hyperplasia and reflux may suggest new "tools" in post-gastrectomy surveillance and help to clarify patterns of gastric carcinogenesis.

Usefulness of colonic motility study in identifying patients at risk for complicated diverticular disease

Colonic motility study was performed on a total of 145 patients. Of these, 55 were patients with symptomatic complicated diverticular disease, 30 had symptomatic uncomplicated diverticular disease, 30 had asymptomatic diverticular disease, and 30 were controls. The pressure sensors were positioned in the descending and the true sigmoid colon. Colonic motility index was significantly higher in symptomatic rather than in asymptomatic diverticular disease in the resting (P less than 0.001) and postprandial (P less than 0.001) states. This confirmed the association between symptomatic diverticular disease and high intraluminal pressure. The patients of the subgroup--complicated diverticular disease--were relatively young (mean age: 51.1 +/- 2.02 years) and had a short history of abdominal pain (18-36 months) and a short segment of colon with diverticula (cm 7.25 +/- 1.31). Our observations suggest that patients showing these indicators are at risk for major complication.

Neuromuscular structures specific to the submucosal border of the human colonic circular muscle layer

The circular muscle layer of the human caecum and ascending colon is clearly subdivided into two portions: an outer one which includes the bulk of the circular muscle layer, and an inner one made up of only six to eight rows of cells. In the right transverse colon no demarcation can be observed, but a difference exists between the innermost and the outermost cells, since those of the two innermost rows possess some peculiarities with regard to the sarcoplasmic reticulum, glycogen particles, caveolae, and intercellular junctions. In the left part of the colon, the circular muscle layer is also divided into two portions. In fact, the innermost smooth muscle cells still possess peculiar morphologies, progressively increase in number, and become separate from each other making up a superficial muscle network. A fibrous lamella, along and inside which a ganglionated nerve plexus runs, is strictly apposed to the submucosal border of the circular muscle layer of the entire colonic length. A second nerve plexus runs between the two portions of the circular muscle layer. Both these plexuses are accompanied by interstitial cells of Cajal in the right colon only. The peculiar organization of the entire submucosal border of the human colonic circular muscle layer distinguishes it from other parts of the gut and probably represents a structural basis for control of human colonic motility. The presence of putative pacemaker cells (interstitial cells and peculiar smooth muscle cells) indicates that the inner border of human colonic circular muscle layer possesses pacemaking activities. Moreover, the interstitial cell--smooth muscle cell ratio differs depending on the colonic level; two main regions can be identified: the right and the left colon. Consequently, we might expect regional variation in pacemaking.

The zona glomerulosa of the adrenal gland in rats with portacaval shunt. An ultrastructural and morphometric study

The zona glomerulosa of the adrenal glands was studied histologically, ultrastructurally and morphometrically in portacaval shunt (PCS)-bearing rats 4 weeks after surgery. Compared with controls, the zona glomerulosa of rats with PCS showed an increase in thickness and a reduction in the number of lipid droplets in the cells of its inner portion, adjacent to the intermediate zone. Moreover, electron microscopy and morphometry of the cells of the inner portion revealed that qualitative and quantitative changes occur, consisting in a decrease in lipid droplets, an increase in the amounts of smooth endoplasmic reticulum and mitochondria, enlargement of the Golgi apparatus, and the appearance of numerous dense bodies at the vascular cell poles. All the above findings indicate that PCS induces an enhanced activity of the fully differentiated cells of the zona glomerulosa, which may be considered as an adaptive response--mediated by an activation of the renin-angiotensin system--to the lowering of the systemic pressure taking place in this experimental condition.

[Diverticular disease of the colon. Concepts to be reviewed for a rational therapeutic approach]

Indicators of a risk group for complicated diverticular disease have been suggested. They are: a) Age 50 years, 2) short history of left lower quadrant abdominal pain, 3) short segment of colon with diverticula, 4) elevated motility index.

Smooth muscle cells, interstitial cells of Cajal and myenteric plexus interrelationships in the human colon

The plane between longitudinal and circular muscle of human colon, as revealed on examination with light and electron microscopes, has no clear-cut border. Some groups of smooth muscle cells, obliquely oriented and with features similar to both circular and longitudinal ones--the connecting muscle bundles--run from one muscle layer to another. Other groups of smooth muscle cells, possessing their own specific ultrastructural features--the myenteric muscle sheaths--, make up envelopes of variable thickness around some myenteric ganglia and nerve strands, partially or completely embedding them in one or other muscle layer. Non-neuronal, non-muscular cells (interstitial cells of Cajal, covering cells, fibroblast-like and macrophage-like cells) complicate the texture of the myenteric muscle sheaths, creating an intricate, interconnected cellular network inside them, widespread among nerve bundles and smooth muscle cells; however, only interstitial cells have cell-to-cell junctions also with the smooth muscle cells and nerve endings. These data document the existence in this colonic area of two different types of muscle cell arrangements, one of which, the myenteric muscle sheath, only contains putative pacemaker cells.

[Esophageal motor abnormalities, gastroesophageal reflux and duodenogastric reflux in patients with Raynaud's disease]

Twenty-four patients with Raynaud's phenomenon, without ARA criteria for classification, were examined, after clinical history, by means of esophageal manometry, combined gastric and esophageal pH-monitoring, endoscopy. The results showed in these patients a high incidence of esophageal motor abnormalities (66.6%), of gastroesophageal reflux (50%), and of duodenogastric reflux (45.8%).

An ultrastructural study of the interstitial cells of Cajal of the human stomach

The interstitial cells of Cajal of the human stomach were studied at the electron microscope. These cells have an exceptionally elongated shape and several lateral branches. Their cytoplasm characteristically possesses cisternae of smooth endoplasmic reticulum and filaments. A capsular-like structure surrounds them and joins them to each other and to the neighbouring nerve endings and smooth muscle cells, and so they all make up anatomical units. Elastic fibres also make bridges between these cells and between smooth muscle cells and nerve endings. Despite these common characteristics, differences in cell number, distribution in respect of the muscle bundles and some cytoplasmic features have been found, depending on where these cells are located. In fact, there are few interstitial cells in the fundus, poor in filaments and branches, and only located inside the circular muscle layer. In the corpus and antrum they are many, rich in filaments and with their numerous branches make interconnected networks, one inside the circular muscle layer, another apposed to its myenteric surface and, in the antrum, a third one apposed to its submucosal surface, which accompany analogous nerve networks. Substantial differences in the contacts between the interstitial cells and the smooth muscle cells and nerve endings have not been found. For their ultrastructural characteristics a smooth muscle nature has been suggested for these cells. A correlation has also been attempted between the electrical and mechanical activities performed by the different gastric areas and the interstitial cell structure and arrangement.

An ultrastructural study of the smooth muscle cells and nerve endings of the human stomach

The circular muscle layer of the human stomach was studied with the electron microscope. The smooth muscle cells differ structurally according to their location. In fact, the circular muscle layer of the fundus is made up of large, irregularly shaped smooth muscle cells, with long, thick, dense bands, and immersed in an abundant, elastic supporting connective tissue. In the circular muscle layer of the corpus (the two curvatures and the corpus between), those located in the outermost zone are identical to that commonly described in the alimentary tract, but are gradually substituted, first by larger irregularly shaped cells, and then, towards the innermost area, by flattened cells richer in sarcoplasmic reticulum, with thick and continuous dense bands on their submucosal surface. The smooth muscle cells of the antrum are all identical to the outermost located corporal ones. The gap junctions are absent in the fundus and in the innermost area of the corporal circular muscle layer, are present in the other areas, particularly frequent in the antrum and in the outermost area of the greater curvature. The number of the nerve endings is similar in the fundus, greater curvature and antrum, while it is two-three times more in the other parts of the corpus. They are located at the periphery of the muscle bundles in the fundus, antrum and greater curvature, sparsely scattered among the smooth muscle cells in the other areas of the corpus and contain small agranular and large granular synaptic vesicles, often mixed in the same axon. These nerve endings lie distant from the smooth muscle cells in the fundus, antrum and greater curvature and directly contact the smooth muscle cells in the other parts of the corpus.

Short-term effects of bile diversion on postgastrectomy gastric histology

Twelve partially gastrectomized subjects who have consecutively undergone total biliary diversion for severe bilious vomiting were studied before and after operation in order to assess the effects of surgery on gastric histology and enterogastric reflux. Before and six months after operation, the following protocol was performed: (1) blood examinations including serum basal gastrin; (2) endoscopy with multiple gastric biopsies; and (3) quantitation of bile acids in the gastric aspirate. Of the preoperative symptoms, bilious vomiting and heartburn completely disappeared postoperatively in all the subjects. Fasting bile reflux was significantly reduced (bile reflux was annulled in six and considerably lowered in the remaining six subjects), and erythema of the gastric mucosa completely disappeared in all the subjects after diversion. Among histological findings, while a significant regression of foveolar hyperplasia was found both in the perianastomotic area and in the body of gastric remnant, none of the other aspects identifiable in postgastrectomy gastric mucosa (chronic gastritis changes included) were affected by diversion. These results show that biliary diversion is effective in correcting reflux, bilious vomiting, erythema, and foveolar hyperplasia of the gastric mucosa and confirm the suggested relationship between bile reflux and gastric foveolar hyperplasia.

The origin and differentiation of adrenocortical cells in rats with portacaval shunt. A structural and ultrastructural study

The formation of adrenocortical cells in the rat was studied by light and electron microscopy in an experimental model, namely portacaval shunt (P.C.S.), in which strong hyperplasia of the cells of the capsular region occurs. The results of this study indicate that in physiological conditions at the level of the adrenal gland capsule some epithelial cells, morphologically distinguishable as dark and clear cells, are found which can be interpreted as precursors of adrenocortical cells. From observations of intermediate forms between capsular precursors and mature adrenocortical cells, which are found in high numbers following P.C.S., it seems that the dark precursors give rise to cells of the zona glomerulosa and the clear precursors evolve into cells of the zona intermedia, which are to be considered as the starting point for the formation of cells of the zona fasciculata.

Content of quinolinic acid and of other tryptophan metabolites increases in brain regions of rats used as experimental models of hepatic encephalopathy

The content of the tryptophan metabolites quinolinic acid (QUIN), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) was measured in various brain areas of rats bearing a portocaval anastomosis (PCA) for 4 weeks, using mass fragmentography or HPLC. In these animals, the content of the excitotoxic compound QUIN increased by 75% in the cortex and 125% in the cerebellum. The content of 5-HT increased by 27% in the brainstem. No changes occurred in other brain areas. On the other hand, the content of 5-HIAA increased by 66% in the cortex, 65% in the caudate, 64% in the hippocampus, 120% in the diencephalon, and 185% in the brainstem. Probenecid administration caused a larger increase of 5-HIAA accumulation in various brain areas of PCA-bearing rats than in those of sham-operated controls. The cortical content of QUIN and 5-HIAA increased after administration of ammonium acetate (7 mmol/kg), whereas an equimolar amount of sodium acetate was inactive. These results confirm that profound changes in the disposition of tryptophan occur in the brains of experimental animals used as models of hepatic encephalopathy. Furthermore, this study adds the excitotoxic compound QUIN to the list of molecules possibly involved in the pathogenesis of this brain disorder.