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Biomedical subjects

G B Ratto

Publications and source records attributed to G B Ratto.

At least 55 records · Page 3Linked to original sources
PubMed1988

The prognostic significance of preoperative assessment of mediastinal lymph nodes in patients with lung cancer.

In order to evaluate the prognostic significance of the preoperative assessment of mediastinal lymph nodes, 100 patients with potentially operable lung cancer underwent two-plane tomography, computed tomography (CT), transbronchial needle aspiration (TBNA; 47 patients), and cervical mediastinoscopy. Mediastinoscopy proved to be the most accurate staging procedure. Tomography was less specific, detecting only advanced mediastinal node involvement, and CT was as sensitive as mediastinoscopy but sensibly less specific. TBNA gave no false positive results but a false negative rate of 25.5 percent. Accurate preoperative staging of mediastinal nodes is mandatory to optimize the resectability rate of lung cancer. Where metastatic involvement of mediastinal nodes was preoperatively documented at more than one level, tumors were invariably unresectable. Mediastinoscopic demonstration of intracapsular metastases at only one level did not preclude complete resection. Before thoracotomy, confirmation of neoplastic spread to mediastinal nodes suggests very low survival rates, especially in patients with incomplete removal of tumors.

Adult↗
PubMed1988

Lung function following upper sleeve lobectomy for bronchogenic carcinoma.

Eight patients who underwent upper sleeve lobectomy and six who underwent upper simple lobectomy for lung cancer were studied. The two groups were matched for age and preoperative lung function as assessed by standard spirometry. Post-operative lung function studies, including measurements of regional ventilation (Vr) and perfusion (Qr) by 133 Xenon technique showed that: 1) two weeks after surgery, forced expiratory volume at 1 s was more reduced after simple than after sleeve lobectomy, but in both groups Vr and its vertical gradient were similarly reduced in the operated lung compared to the contralateral; 2) one year after sleeve lobectomy, the vertical gradient of Vr tended to disappear in both lungs while Vr and Vr/Qr of the operated side increased significantly. These results indicate that early after surgery lung function may be less impaired after sleeve than simple lobectomy; however, long-term changes of regional lung function may occur after sleeve lobectomy resulting into a high Vr/Qr ratio in the operated lung.

Adult↗
PubMed1988

Survival after incomplete resection or exploratory thoracotomy in patients with advanced non small cell lung cancer.

In order to evaluate the effects of incomplete resection or exploratory thoracotomy on survival, 75 patients with Stage III non small-cell lung cancer (NSCLC) were studied. Twenty-five subjects underwent incomplete resection, 25 had exploratory thoracotomy and 25 patients who were denied surgery served as controls. Standard radio-therapy and chemotherapy regimens were given to most patients. The 2-year survival rates were 14%, 7% and 9% following incomplete resection, exploratory thoracotomy or conservative treatment, respectively. The survival curve was significantly worse in the exploratory thoracotomy group than in the control group (p less than 0.05). Major complications occurred in 2 patients after incomplete resection (bronchopleural fistula; chylothorax) and in 3 patients following surgical exploration (atelectasis). Two post-operative deaths were recorded in the exploratory thoracotomy group. In conclusion, the survival rate at 2 years in patients with Stage III NSCLC is not modified by incomplete or exploratory surgery. Moreover, exploration seems to worsen the outlook of patients during the first 2 years from diagnosis.

Carcinoma, Non-Small-Cell Lung↗
PubMed1988

Effects of antrectomy and proximal duodenectomy on duodenal G-cell activity and proliferation in the rat.

The role of the antrum and duodenal bulb in gastrin regulation was investigated in 60 white rats, submitted to 1) simple laparotomy, or 2) antrectomy, or 3) antrectomy with additional removal of the duodenal bulb (1.5 cm). Serum gastrin levels 3-4 months after surgery were repeatedly measured with radioimmunoassay in fasted and in freely fed rats. The duodenum was thereafter removed and its proximal third used to assess the number and cytoplasmic granule content of duodenal G-cells. Basal serum gastrin levels were significantly increased by antrectomy, but reduced by additional resection of the duodenal bulb. Antrectomy, with or without proximal duodenectomy, completely abolished the gastrin response to feeding. Duodenal G-cell density was increased following antrectomy, but the phenomenon was not further enhanced by additional removal of the duodenal bulb. No significant changes in the patterns of gastrin granule maturation were found after antrectomy and proximal duodenectomy.

Animals↗
PubMed1987

Role of the proximal duodenum in gastrin regulation following antrectomy.

Antrectomy is accepted as the most effective surgical treatment of recurrent duodenal ulcer after complete vagotomy. Although antrectomy is aimed at reducing serum gastrin levels, both human and experimental reports seem to indicate that gastrin concentrations may be unchanged following this operation. The probable source of gastrin has been considered to be the proximal third of the duodenum, since at this level increased tissue gastrin concentrations were found after antrectomy. The present study was carried out in order to gain insight into the mechanism by which the duodenum may compensate for the removal of the antrum. Forty white rats were randomly divided into two equal groups and underwent antrectomy with gastroduodenostomy or simple laparotomy. Three to four months after surgery, serum gastrin determinations were carried out by radioimmunoassay both in fasted and freely fed rats. The duodenum was then removed and its proximal third was used for G cell counts (immunoperoxidase method) and for assessment of G cell cytoplasmic granule distribution (electron-microscopic examination). Antrectomy significantly increased fasting serum gastrin levels (p less than 0.01), while it completely abolished the gastrin response to food ingestion (p less than 0.001). In antrectomized rats, the duodenal G cell number was significantly higher than in control rats (p less than 0.001), whilst the G cell cytoplasmic granule number remained unchanged. In conclusion, the present study indicates that in the rat the proximal duodenum increases its content of tissue gastrin following antrectomy mainly by enhancing the regional G cell density.

Animals↗
PubMed1987

Selective surgical resection in the management of small-cell carcinoma of the lung.

There is increasing evidence that selected patients with small-cell carcinoma of the lung (SCCL) may benefit from surgical resection. Since 1983, sixteen patients (aged 40-72 years) with limited SCCL underwent surgical resection before any other treatment. Criteria for patient selection were the following: 1) no pre-operative histological diagnosis or 2) pre-operative diagnosis of T1 or T2 SCCL, without evidence of both distant and mediastinal node metastases. All patients had potentially, curative resection (lobectomy: 11 cases; pneumonectomy: 5 cases). Postoperatively patients were classified as stage I in 7 cases, as stage II in 3 cases and as stage III in 6 cases. All subjects but one subsequently received adjuvant chemotherapy (Cisplatin; Adriamycin; VP-16). Prophylactic cranial irradiation was not given. Median survival time was 15.2 months for the whole group of patients, 19.6 months for stage I patients, 16 months for stage II patients and 9.7 months for stage III patients. The 2-year survival rate was 32% for all cases, 63% for stage I cases and 0% for stage II and stage III cases. Three stage I patients are alive and disease-free, 24, 26 and 31 months after resection, respectively. The brain was the most common site of initial relapse in stage I cases. These results suggest that surgery might favor intrathoracic disease control exclusively in stage I and stage II patients. Resection seems to be contraindicated in N2 tumors. If treatment policy is to achieve total disease control, prophylactic cranial irradiation should be recommended, notably in patients with stage I SCCL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Clinical, biochemical and ultrasonographic findings of choledochal sphincteroplasty. A 1 to 14 year follow-up study.

Sixty patients, who underwent choledochal sphincteroplasty and then yearly referred to the department for a diagnostic check-up, entered this study. Follow-up ranged from 1 to 14 years after surgery. Check-up examination included: 1) clinical assessment, 2) serum liver and pancreas function tests, and 3) ultrasonography. Good long-term clinical results were obtained in 50 cases. Seven patients complained of mild and temporary hepatic symptoms or digestive troubles. Three subjects developed severe symptoms: jaundice, fever, pain or ascites. The causes of the failures were: 1) recurrent stones in the distal portion of the common bile duct with cholangitis, 2) common hepatic duct stricture with recurrent stones and cholangitis, and 3) alcoholic cirrhosis. The following conclusions may be drawn: 1) Sphincteroplasty achieved a fourteen year success rate of 90% 2) Cholangitis, which supervened in 2 patients, was associated with bile duct strictures and recurrent stones. 3) The great majority of patients who had undergone sphincteroplasty, showed normal size of the bile ducts. However, 10% of patients still retained some degree of intrahepatic ductal dilatation. 4) Since recurrent bile duct stenoses occurred as far as 6 and 8 years after surgery, long-term follow-up is mandatory.

Adult↗
PubMed1986

Influence of the colonic environment on duodenal G-cell activity and proliferation.

To investigate the effects of the colonic environment on duodenal G-cell activity and proliferation, thirty white rats underwent antrectomy with gastroduodenostomy (control group) or antrectomy with interposition of a 15 mm segment of transverse colon between the gastric fundus and the first duodenal portion (experimental group). Three to four months after surgery, serum gastrin determinations were carried out by radioimmunoassay either in fasted or freely fed rats. The duodenum was then removed and its proximal third was used for G-cell count (immuno-peroxidase method) and for assessment of G-cell cytoplasmic granule content (electron microscopy examination). The interposition of a colonic segment between the gastric fundus and the first duodenal portion did not affect either serum gastrin levels or the cytoplasmic granule content of duodenal G-cells, while significantly increasing duodenal G-cell density. These results indicate that the colonic environment enhances duodenal G-cell proliferation, but gastrin release from the enlarged duodenal G-cell mass is not stimulated by the interposition of a colonic segment to replace the antrum, either under fasting or feeding conditions.

Animals↗
PubMed1986

Use of the polytetrafluoroethylene surgical membrane for control of intra-abdominal adhesions.

The new polytetrafluoroethylene (PTFE) surgical membrane is specifically designed to prevent adhesion formation. The present study was planned in order to evaluate the effectiveness of the PTFE surgical membrane as a parietal peritoneal substitute. Furthermore, the effects of the suture material used to implant the membrane under different operating conditions (clean or contaminated surgery) were also evaluated. One hundred-eighty rats were divided into 9 groups and underwent the following surgical procedures: Group 1: removal of a parietal peritoneum patch, which was left unrepaired; Group 2: a similar peritoneal defect was covered with the PTFE membrane by 8 polypropylene sutures; Group 3 (control group): only the 8 polypropylene suture were placed on the margin of the standard peritoneal defect; Group 4: the same procedure as in Group 2, using as sewing material PTFE sutures; Group 5 (control group): only the 8 PTFE sutures were placed on the margin of the standard peritoneal defect; Group 6, 7, 8 and 9: the same procedures as in Group 2, 3, 4 and 5 respectively, adding division and subsequent reanastomosis of the caecum. Animals of each group underwent a second laparotomy 10 days or 3 months after surgery for evaluation of the extent and density of adhesions, and of the intraperitoneal organ involvement. Histological examination of adhesions which formed was then carried out. No adhesions developed in rats of group 1, while they were always present in all the other groups. Under clean surgery, the adhesions were limited to the margin of the peritoneal defect, while under contaminated surgery they formed also on its central portion. The PTFE surgical membrane itself caused variations neither of the extent and density of adhesions which developed nor of the magnitude of intraperitoneal organ involvement. The type of suture material used to implant the membrane had no effect on adhesion formation.

Abdomen↗
PubMed1984

Healing of experimental defects on the stomach: influence of autologous and heterologous materials.

This study was undertaken to evaluate the influence of various autologous and heterologous structures on gastric defect healing. In 210 rats, standard gastric defects were closed using the following structures as patches: (1) pedicled colonic patches, (a) mucosal layer to lumen, and (b) peritoneal surface to lumen; (2) leiomuscular colonic buttons; and (3) lyophilized bovine tendon collagen sponges. The specimens were removed from the defect areas at standard time intervals ranging from 2 to 12 months after surgery; the samples were then examined by light microscopy (hematoxylin-eosin; Azan Mallory; Grimelius methods) and by transmission and scanning electronmicroscopy. The colonic mucosa appeared to be the most resistant of the structures to gastric secretions; it showed no mucosal disruption during the entire period of observation and also underwent a progressive gastric-like morphological transformation. In all the other cases, the healing process involved the initial development of granulation tissue followed by scar tissue with gastric mucosa growing over the scar tissue to fill the defects.

Animals↗
PubMed1983

[Morphological findings and functional considerations on the structural adaptation of colonic grafts on the rat stomach].

Structural changes of colonic patches implanted in rat stomachs for periods of 2 to 12 months were evaluated by standard light and scanning electron microscopy. Colonic patches were sutured on the posterior wall of 116 white rats stomach body according to the following models: 1) mucosal surface to gastric lumen (60 rats); one third of the animals were given chronic doses of histamine subcutaneously; 2) peritoneal surface to gastric lumen (28 rats); 3) leiomuscular layers to gastric lumen by removing of the colonic mucosa (20 rats). Eight rats were used as controls. The colonic mucosa was shown to be highly resistant to acid secretions; only minimal surface erosions were found in animals with gastric hypersecretion following histamine stimulation. In contrast both the peritoneal surface and the colonic leiomuscular components were completely destroyed by contact with the acid juice. Both these structures were subsequently and completely colonised by the gastric mucosa.

Adaptation, Biological↗
PubMed1983

[Artificial blood. Experimental studies on fluorocarbons as chemical blood substitutes].

Fluorocarbonates are organic compounds capable of carrying oxygen and surrendering it to tissues by means of biological sound modalities. Experimentation of an emulsion consisting of perfluorotripropylamine and perfluorodecaline (Fluosol DA 20%) as a blood substitute is reported. Acute (Ht less than 1%) and chronic morphological (Ht = 15%) studies were performed on rats, and a semi-acute biochemical and morphological protocol (Ht = 21%) was experimented in pigs. The first signs of altered cerebral electrical activity occurred at Ht = 2% in the acute experiments, and death due to respiratory arrest took pace at Ht = 0.5%. In the semiacute and chronic experiments, widespread infiltration of fluorocarbonic micelles was noted on histological and electron microscope lung and liver preparations.

Acid-Base Equilibrium↗
PubMed1983

Morphological evaluation of the human umbilical vein graft. An experimental study.

23 human umbilical vein segments (5 mm X 4-5 cm) were implanted into the carotid and iliac arteries of 15 dogs, removed at intervals ranging from 10 to 360 days after surgery and analyzed by light and scanning electron microscopy. 10 days after implantation, a thin layer of fibrin covered the central areas of the grafts, while thick platelet aggregates were found near the anastomoses. After 30 days, the progressive connective tissue ingrowth led to the organization of a thin fibrous inner layer on which endothelial-like cells grew, spreading from both anastomoses. The endothelialization process appeared to be almost complete at 120 days after implantation, while at 360 days the flow surface was totally lined.

Animals↗
PubMed1983

[Small-caliber arterial prostheses: influence of porosity].

Thirty-two pyrolytic carbon coated Weavenit dacron grafts and 32 human umbilical vein segments treated with glutaraldehyde were implanted in the carotid arteries of 32 dogs. Prosthesis samples were removed after periods varying from 10 to 120 days, and sections examined by optical microscopy. Internal surfaces were studied by scanning electron microscopy. Overall permeability was 93.7 p. cent for the dacron prosthesis and 84.3 p. cent for human umbilical vein sections. Fundamental stages of the pseudointimal organization process were compared for the two types of prosthesis.

Animals↗