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.

Ultrastructure of striated muscle fibers in the middle third of the human esophagus.

Striated muscle fibers and their spatial relationship to smooth muscle cells have been studied in the middle third of human esophagus. Biopsies were obtained from 3 patients during surgery. In both the circular and longitudinal layers, the muscle coat of this transition zone was composed of fascicles of uniform dimension (100-200 microns of diameter); some of these bundles were made up of striated muscle fibers, others were pure bundles of smooth muscle cells and some were of the mixed type. Striated muscle fibers represented three different types, which were considered as intermediate, with certain structural features characteristic of the fast fiber type. Of these, the most frequently-found fibers were most similar to the fast fiber type. Satellite cells were numerous; in mixed fascicles they were gradually replaced by smooth muscle cells. The gap between striated muscle fiber and smooth muscle cells was more than 200 nm wide. It contained the respective basal laminae and a delicate layer of amorphous connective tissue. No specialized junctions were formed between consecutive striated muscle fibers, or between striated muscle fibers and smooth muscle cells. Interstitial cells of Cajal were never situated as close to striated muscle fibers as to smooth muscle cells.

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.

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.

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.

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.

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.

[Somatostatin receptors in non-endocrine tumours]. / Recettori per la somatostatina in tumori non endocrini.

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.

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.

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.

[Diverticular disease of the colon. Concepts to be reviewed for a rational therapeutic approach]. / In tema di malattia diverticolare del colon. Concetti da rivedere per un indirizzo terapeutico razionale.

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.

[Esophageal motor abnormalities, gastroesophageal reflux and duodenogastric reflux in patients with Raynaud's disease]. / Anomalie motorie esofagee, reflusso gastroesofageo e reflusso duodenogastrico in pazienti con fenomeno di Raynaud.

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%).

[Barrett esophagus. Diagnosis and treatment]. / Esofago di barrett. Diagnosi e terapia.

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.