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Biomedical subjects

G B Ratto

Publications and source records attributed to G B Ratto.

At least 37 records · Page 2Linked to original sources
PubMed1991

Comparative evaluation of acid- and bile-induced damage to pedicled jejunal or colonic segments in the rat.

The choice of the esophageal substitute after surgical resection for peptic stricture lies between the colon and jejunum. The current study was designed to compare long-term resistance of the colonic and jejunal mucosa to gastric or mixed duodenogastric secretions. The following preparations were performed in Wistar rats: transposition of a colonic or jejunal patch (a) to the gastric body, with or without truncal vagotomy, or (b) to the gastric antrum and proximal duodenum, with or without truncal vagotomy. Jejunal and colonic patches were removed 4, 8, and 12 months after surgery. The only damage to the transposed mucosae was the alteration of microvilli. The alteration was more severe in colonic than in jejunal patches and was prevented by truncal vagotomy. Long-term resistance of the transposed mucosae to the environmental challenge may depend on their adaptation potentiality, involving both specific and nonspecific mechanisms. Nonspecific mechanisms include the increased production of mucus and the gastric-like transformation of the superficial epithelial layer. Specific mechanisms include the reduction of the mucosal surface size for jejunal segments and the shifting in mucin secretion patterns for colonic segments.

Animals↗
PubMed1991

Pyloric antrum gastrin cell hyperplasia after jejunum or colon transposition: effects of jejunal or colonic mucosa on G cells.

Jejunal or colonic segments are currently used as esophageal substitutes after resection of intractable peptic stenoses. The present study was carried out in order to investigate the effects of the jejunal or colonic mucosa on antral gastrin (G) cells. Colonic or jejunal patches with intact vascular supply were sutured to the pyloric antrum or the higher portion of the gastric body in 40 rats. Ten further animals were used as controls. Three to 4 months after surgery, the serum gastrin levels were weekly determined in fasted (24 h) and freely fed rats using radioimmunoassay. The pyloric antrum was then removed, and the G cell density was assessed with an immunoperoxidase method. Transposal of the colonic mucosa to the antrum increased G cell density and basal serum gastrin levels, while grafting of the jejunal mucosa did not. G cell proliferation proved to be dependent on the topographic location of the colonic patch with respect to the pyloric antrum. Serum gastrin values in freely fed rats tended to be greater in the colon-to-antrum transposition group than in the other experimental groups, but the difference was not significant. In conclusion, variations between the properties of the jejunal and colonic mucosa would include their uneven effects on antral G cells.

Animals↗
PubMed1991

Glutaraldehyde-tanned mandril-grown grafts as venous substitutes.

The present study was performed to evaluate the potential of glutaraldehyde-tanned mandril-grown grafts as caval substitutes. Short-term experiments consisted of 30 tubular grafts (35 x 8 mm), either of tanned collagen or polytetrafluoroethylene, that were sutured in the infrarenal inferior vena cava of pigs and removed 1 hour after implantation. There was no significant difference between the extent of the thrombus-lined graft surface in the biologic group and that in the polytetrafluoroethylene group. The amount of inner thrombus on tanned collagen grafts was significantly correlated to platelet activity. Long-term experiments involved 30 similar segments of both materials, which were sutured in the inferior vena cava and harvested 7, 14, 28, 56, and 112 days after operation. The 112-day patency rate of collagen grafts was 67%. The 56-day patency rate of polytetrafluoroethylene grafts was 16%. The difference was statistically significant (p less than 0.01). Collagen grafts were lined by a thin neointima (200 micron) in all but two cases. The neointima was completely endothelialized within 4 weeks from implantation. In conclusion, tanned collagen grafts may represent a suitable material for venous replacement.

Analysis of Variance↗
PubMed1990

[Tumor markers. I. Their significance in the preoperative assessment of lung neoplasms].

The present study has been carried out in order to evaluate the role of tumor markers in the presurgical assessment of patients with bronchial carcinoma. The carcinoembryonic antigen (CEA), the neuron specific enolase (NSE), the tissue polypeptide antigen (TPA), the carbohydrate antigen 19-9 (CA 19-9) and the carbohydrate antigen 50 (CA 50) have been preoperatively measured in 133 subjects with potentially resectable lung cancers, and in 75 healthy smokers. Sixty-one patients had squamous cell carcinoma, 55 adenocarcinoma and 17 small cell carcinoma. Lobectomy (or bilobectomy) was performed in 74 cases, pneumonectomy in 36 cases, exploratory thoracotomy in 15 cases and a palliative resection in 8 cases. When individual markers were considered, TPA showed the highest sensitivity (85%) and CA 19-9 the lowest sensitivity (11%). Specificity was uniformly superior to 90%. When marker associations were considered, the combined measurement of TPA and NSE gave the best results: both the sensitivity and specificity rates approached 90%. The application of the TPA-NSE association allowed detection of 94% of small cell carcinomas, 89% of adenocarcinomas and 85% of squamous cell carcinomas. A positive correlation was found between the complete resectability of lung cancer and serum levels of CEA, CA 50 and CA 19-9. By using the discriminant analysis, a statistical model yielding identification of about 74% of patients with tumors which were judged potentially resectable according to the pre-operative non-invasive diagnostic procedures and were found to be unresectable at thoracotomy, has been get available.

Adenocarcinoma↗
PubMed1990

[Tumor markers. II. Their significance in the follow-up of patients after radical resection of lung neoplasms].

The clinical field in which tumor markers proved to be most useful is the monitoring of cancer patients. The present study was carried out in order to evaluate the role of tumor markers in the prognostic assessment, and pre-clinical identification of disease recurrence in patients with completely resectable non-small cell bronchial carcinoma. Tumor markers have been measured: a) pre-operatively, in 109 patients with resectable lung cancer and b) post-operatively, in 61 patients who underwent complete resections and were followed for at least one year after surgery. The carcinoembryonic antigen (CEA), the neuron specific enolase (NSE), the tissue polypeptide antigen (TPA), the carbohydrate antigen 19-9 (CA 19-9) and the carbohydrate antigen 50 (CA 50) have been determined in each patient. Long-term survival was significantly correlated with serum levels of the CEA, CA 50 and CA 19-9, while not with those of TPA and NSE. For pre-clinical detection of cancer recurrence, TPA and NSE were the most suitable indicators.

Adenocarcinoma↗
PubMed1990

[The prognostic value of Jass' histopathological classification of cancer of the left colon and rectum].

Histological material from 121 patients who underwent surgery for cancer of the left colon and rectum was reexamined by two pathologists according to criteria put forward in Jass' histopathological classification. A prevalence of Jass' grades II (36.4%) and III (47.9%) were observed in this series. There was no correlation between the site of neoplasia but there was a clearly increased incidence of advanced stages C and D according to Dukes-Kirklin's classification within Jass' grades II, III and IV (p less than 0.005) and growth pattern, but not for the configuration of tubules. The new histopathological model proved to be more reliable in prognostic terms in the case of cancer of the rectum compared to that of the left colon, but at present its clinical significance is limited to specifying the site and stage of the neoplasia. The latter was found to be the most reliable prognostic parameter.

Adenocarcinoma↗
PubMed1990

Improving clinical efficacy of computed tomographic scan in the preoperative assessment of patients with non-small cell lung cancer.

The criterion of choice for computed tomographic scan identification of metastatic mediastinal nodes is not clearly fixed. This prospective study was designed to define the most suitable computed tomographic criterion for detection of nodal metastasis, enabling improvement of the test's clinical efficacy. One hundred twenty-three patients with potentially operable non-small cell lung cancer underwent mediastinal evaluation by computed tomographic scan and cervical mediastinoscopy followed by thoracotomy with mediastinal node dissection. There were 116 men and seven women; the mean age was 59.3 +/- 9.1 years. Forty-six tumors were classified after operation as stage I, 20 as stage II, 27 as stage IIIa, and 30 as stage IIIb. Mediastinal nodes were classified as metastatic according to the following computed tomographic scan criteria: (1) shorter axis 1 cm or larger; (2) shorter axis 1.5 cm or larger (nodes less than 1 cm were classified as negative and those 1 to 1.5 cm as indeterminate); and (3a) shorter axis 1 cm or larger, plus evidence of central necrosis or discontinued capsule, or (3b) shorter axis 2 cm or more, regardless of the nodal morphologic condition. The highest sensitivity rate was achieved by using criterion 1 (90%) and the poorest by criterion 3 (75%). The greatest specificity rate was obtained by applying criterion 3 (90%) and the lowest by criterion 1 (54%). The prediction by using computed tomographic criterion 3 correlated better with pathologic findings than that derived by adopting the criterion 1 or 2. When mediastinal nodes were identified as negative according to criterion 1, 2, or 3, the complete resection rate was 92%, 92%, or 95%, respectively, rendering cervical mediastinoscopy unnecessary. When mediastinal nodes were classified as positive, the resectability rate was 55%, 27%, or 13%, respectively. In these instances cervical mediastinoscopy allowed identification of different degrees of mediastinal involvement; it proved to be the most useful procedure for preoperative selection of those patients with N2 tumors who are amenable to a complete resection. In conclusion, the use of computed tomographic criterion 3 does improve the clinical efficacy of the test, by sparing a large number of unnecessary mediastinal explorations, without increasing the rate of useless thoracotomies.

Adenocarcinoma↗
PubMed1990

[Immediate and long-term results of endoscopic or surgical Oddi sphincterotomy in the treatment of lithiasis of the common bile duct].

Ninety-one patients with choledocholithiasis were admitted for endoscopic (51 cases) or surgical (40 cases) sphincterotomy of Oddi's muscle, and were followed up on a yearly basis thereafter for a period spanning 1 to 5 years. The study protocol included clinical examinations, ultrasonographic investigations and biochemical tests. The post-surgery mortality rate was 3.9% following endoscopic sphincterotomy versus 0% after surgery. Postoperative complications occurred in 3.9% of patients treated endoscopically (bleeding, angiocholitis) and in 5% of surgical patients (bronchopneumonia, suppuration of abdominal wall). Attempts to remove calculi via endoscopic Oddian sphincterotomy failed in 37% of cases. Long-range results were classified as excellent or good in 92% of patients treated endoscopically, and in 100% of cases treated surgically. Endoscopic division of Oddi's sphincter was unsuccessful in 4 patients (8%), who either had recurrent bile-duct stones (2 cases) or developed sphincteric stenosis. Among biochemical indices of biliary stasis, only alkaline phosphatase contents showed a greater increase following endoscopic sphincterotomy than after surgical treatment. Ultrasonographic studies of the bile duct evidenced a greater incidence of air entrapment in the bile ducts of patients subjected to surgical sphincterotomy.

Adult↗
PubMed1990

[Magnetic resonance imaging of low intensity field in the follow-up of pneumonectomized patients].

The authors investigated the real contribution of low-field MR imaging in the follow-up of pneumonectomized patients. Literature on the subject is surprisingly poor, even though MR diagnostic capabilities seem to be great in these patients. Because of the peculiar anatomical features of pneumonectomized patients, low-field MR imaging yields high-quality images. The operated hemithorax, with the postpneumonectomy space full of fluid, in the absence of respiratory movements is free of movement artifacts. The latter are known to worsen image quality in thoracic MR imaging, especially without respiratory gating. In the study of mediastinum and operated hemithorax MR imaging provides the highest diagnostic contribution. In the mediastinum MR images demonstrate enlarged lymph nodes and tumor recurrences and is superior to CT especially when great vessels are involved. In the study of the operated hemithorax, MR imaging is preferable to CT to identify parietal lesions, because of its higher spatial resolution. Moreover, MR imaging allows tumor recurrences to be differentiated from normal muscular tissue and from fibrous tissue on the basis of their different signal intensities as observed on the various pulse sequences.

Female↗
PubMed1990

[Prosthesis replacement of the inferior vena cava].

The development of reconstructive venous surgery has been hampered by the lack of suitable graft materials. Fourteen carbon fibre grafts (phi: 8 mm), 30 glutaraldehyde treated ovine collagen grafts and 29 polytetrafluoroethylene (PTFE) grafts were used to replace a 35 mm segment of infrarenal inferior vena cava in pigs. Prostheses were removed 1 hour and 7, 14, 28, 56 and 112 days after implantation. All specimens were examined by light and scanning electron microscopy. The 112 day patency rate was 67% for ovine collagen grafts, while all carbon and PTFE grafts thrombosed. The difference was statistically significant (p less than 0.01). During the first hour after implantation, a thick (800-900 microns) thrombotic layer deposited on the inner surface of carbon grafts. This layer possibly caused the subsequent complete occlusion of the tubular segments. A thin neointima (less than 200 microns) developed on the flow surface of ovine collagen prostheses. This favoured complete endothelialization of the graft inner surface as soon as four weeks after surgery. In conclusion, glutaraldehyde treated ovine collagen would represent the first sound material to be used as venous substitute.

Animals↗
PubMed1989

[Evaluation of regional perfusion as an indicator of resectability in patients with centrally located bronchogenic carcinoma].

The value of using regional ventilation (V) and perfusion (Q) tests as signs of resectability has been analysed in 17 patients with centrally located lung cancers who underwent thoracotomy. The criteria for inclusion into the study were the following: (1) histological diagnosis of non-oat-cell carcinoma, (2) no distant metastases, (3) Q in the affected lung less than 40% and (4) evaluation by computed tomography of the extent of the tumor. Regional perfusion was investigated by intravenously injected 133 Xenon. CT scan proved to be the most sensitive test (90%) in order to identify non-resectable lesions; in 2 cases, however, the tumor was erroneously judged non-operable (specificity = 71%). For the evaluation of V and Q data, two parameters were assumed as a non-resectability index: (1) Q less than or equal to 30% and (2) V/Q greater than or equal to 1.5. Sensitivity was 80% for the former and 70% for the latter parameter, while specificity was 85% and 100% respectively. In conclusion, V and Q study may provide highly specific informations on the resectability of centrally located lung cancers, especially when assuming V/Q greater than or equal to 1.5 as discriminating value.

Carcinoma, Bronchogenic↗
PubMed1989

[Sessile tubulo-villous polyps in the rectum: problems of diagnosis and treatment. Personal experience].

A retrospective analysis was performed on 22 patients (mean age 65) in whom preoperative rectosigmoidoscopy had diagnosed tubulovillous rectal polyp. In 12 cases the polyps were removed transanally and the remaining 10 were subjected to laparotomy. The incidence of error in the preoperative histological diagnosis was 18.2% (9% for the nature and 10% for degree of dysplasia of the polyp). There were 25% recurrences after transanal exeresis, 10% after laparotomy. Total survival at 42 months was 86.3%. The study confirms the validity of transanal exeresis of tubulovillous polyps of the rectum assuming careful preoperative patient selection.

Aged↗
PubMed1989

[Colorectal cancer: prognosis after curative surgical treatment without extended elective lymphadenectomy in patients in Dukes C stage].

A retrospective analysis has been carried out on a group of 103 Dukes C cases from a series of 412 patients with colorectal carcinoma, operated on from January 1970 to November 1983. The 5-year survival rate was 32% in patients who had a curative resection (median survival: 24 months). Larger numbers of lymph nodes were obtained with right or left colectomy. As regards the treatment of rectal cancer, similar numbers of nodes were obtained either with anterior resection or with Miles' operation. Prognosis was significantly correlated to tumor location, number of involved nodes (p less than 0.01) and grading of the primary tumor (p less than 0.01). The use of extended left colectomy with elective abdominopelvic lymphadenectomy was associated with a small raise of survival and a definite increase of perioperative morbidity and mortality compared to conservative surgical resection.

Adult↗
PubMed1989

Endoscopic papillosphincterotomy and surgical sphincteroplasty for the treatment of bile duct stones: a comparative analysis.

UNLABELLED: One hundred and ten subjects with cholelithiasis entered this retrospective study. Early and late results of 73 patients treated by endoscopic papillosphincterotomy (EPST) were compared to those of 37 patients who had surgical transduodenal papillo-sphincteroplasty (SST). The comparative analysis was made in terms of clinical, biochemical and ultrasonographic findings. The follow-up period ranged from 1 to 5 years in the first group and from 1 to 15 years in the second group. EPST and SST proved to be comparable in regard to operative mortality and morbidity. EPST failed in removing large or impacted bile duct stones in 47% of cases, while SST was uniformly successful. Long-term results were good in most patients, either when treated by EPST or SST. The 5-year failure rate was 8% after EPST and 0% after SST. In the surgical group, the 15-year failure rate was 5%. Serum alkaline phosphatase levels were higher after EPST than after SST, suggesting the persistence of some degree of biliary stasis in endoscopically managed patients. Pneumobilia was detected more often in surgical patients, indicating that SST does create a wide and permanent communication between the duodenum and the biliary system. IN CONCLUSION: 1) EPST may achieve acceptable success rates with low mortality and morbidity, even in high risk patients; 2) the high number of long-term good clinical results seems to indicate that sphincter re-stenosis after EPST is rare, at least for the first 5 years from operation; 3) SST is an effective and safe procedure, ensuring excellent long-term results, provided that the technique of and the indication for are correct (including Wirsung assessment); 4) the wide and permanent stoma created by SST is not associated with recurrent cholangitis, if bile duct re-stenosis does not occur.

Ampulla of Vater↗
PubMed1989

[A new type of small calibre carbon fiber arterial prosthesis].

A new type of vascular prosthesis, made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen grafts (4 x 33 mm) were implanted on the infrarenal aorta and removed 15 s, 60 m and 7, 15, 30, 60 and 120 days after surgery. Specimens were examined by light and scanning electron microscopy. As controls ten pigs underwent excision and re-implantation of a 30 mm segment of infrarenal aorta. Autografts were removed 7 to 120 days after surgery. All but one carbon grafts, as well as all autografts were patent at the time of removal. Basic characteristics of carbon grafts, as shown by the present study, may be summarized as follows: 1) thromboresistance of the inner surface, at the time of implantation, 2) development of a thin neo-intima, 3) rapid and complete endothelialization of the flow surface, 4) good viability of the inner layers and 5) solid anchorage to peri-graft tissues.

Animals↗
PubMed1989

[Carbon fiber composite biomaterials in the substitution of the inferior vena cava].

A new type of vascular prosthesis made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen graft (8 x 30 mm) were implanted as inferior vena cava (IVC) substitutes. The blood conduits were removed 15 s, 60 min and 7, 15, 30, 60 and 120 days after implantation. Specimens were examined by light and scanning electron microscopy. Ten similar pigs underwent excision and re-implantation of 30 mm segment of IVC, and where used as controls. Carbon fibres grafts removed within 7 days after implantation were patent: at the subsequent observation times, the prosthetic segments appeared completely or partially thrombosed. Four of the 10 venous autografts failed. Shortly after implantation, a thick neointimal layer covered the inner surface of carbon grafts. This phenomenon delayed organization and neo-endothelialization of the neointima, exposing carbon segments to blood deposits.

Animals↗
PubMed1989

Postoperative surveillance of colorectal cancer according to risk category.

Over about a 7-year period, 138 colorectal cancer patients undergoing potentially curative surgery were prospectively entered into postoperative surveillance programs that differed according to risk category. Of the 138 patients, 28 (20%) have been lost to follow-up. Of the 110 remaining patients, thirty (27.3%) were classified as low risk cases since they had stage A-B1, well differentiated tumors (G1) primary tumors with preoperative CEA values of less than 7.5 ng/ml (group 1) and the remaining 80 patients (72.7%) were considered high risk cases (group 2). Overall 5 year survival was 64.5%; group 1 patients had a significantly better 5-year survival rate (90%) as compared to group 2 patients (55%) (p less than 0.01). Of the 20 asymptomatic patients with distant metastases only 4 (20%) underwent potentially curative surgery, whereas of 13 asymptomatic patients who recurred locally surgery was undertaken in 9 (69%) (p less than 0.05). At 5 years from the diagnosis of local recurrence, 5 of 11 patients (45.4%) who underwent curative second-look surgery are still alive. The survival of low risk patients was not negatively influenced by less frequent follow-up. Endoscopy and echotomograms were the most useful diagnostic tools in detecting early local anastomotic recurrence and hepatic metastases, respectively. Individualized follow-up programs for various risk categories of colorectal cancer patients are recommended.

Adult↗