The DNA-methylase reaction in evolution and differentiation.
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Biomedical subjects
Publications and source records attributed to P Volpe.
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DNA of OV40-transformed 3T3 cell line is more methylated than that of normal cells. Integrated sequences of OV40 DNA, however, are methylated less than the host DNA. Virus-specific sequences are flanked by highly methylated areas of cellular DNA of intron nature. The virus-specific pre-mRNA isolated from nuclei (28-37 S) is capable of hybridization with the low-methylated region of early OV40 genes coding for T-antigen, highly methylated exon containing a signal for polyadenylation and stop-codon. After processing, the virus-specific mRNA (19 S) extracted from polysomes loses the capacity of hybridization with highly methylated intron apparently due to splicing. On the other hand, the early gene of the virus is mapped in the A fragment obtained by combined hydrolysis of OV40 DNA with ECO RI, BamHI and Bg III. Because this fragment is shorter (2.6 Kb) than virus-specific mRNAs, it is assumed that T-antigen (mol. mass 94,000) is a hybrid protein containing amino acid sequences coded for by cellular DNA. From this point of view, integration of OV40 DNA leads to the formation of a "virus-cell transcription unit" for T-antigen, and multiple integration may be associated with repetition of the same target.
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Between 1986 and 1994 13 patients with spontaneous internal biliary fístula were operated at the Hospital das Clínicas of the University of São Paulo. Ten were patients women and three were men. Their mean age was 55.2 years (range 30 to 87 years). The etiology was cholelithiasis in all cases and the most frequent type of fístula was cholecystoduodenal. There was no mortality. A review of literature of this condition and a discussion about the diagnosis, treatment and etiopathogenesis are presented.
Anaphylactic reactions to colloid volume substitutes, such as dextran, are rare, however, with their increasing utilization in clinical practice an increasing awareness of their potential antigenicity is required. This article reports a severe allergic reaction induced by infusion of dextran 40 during the beginning of a general anesthesia in a 59 year old patient who was going to be submitted to an operation for treatment of chagasic megacolon. The patient died from this complication after 28 days. A review of literature of this complication and a discussion about its physiopathological mechanism and prevention is presented.
Injury of the extra-hepatic biliary tract is infrequent, occurring in approximately 3.5% of all patients with blunt and penetrating abdominal trauma. The incidence of this injury caused by blunt abdominal trauma is rare. PURPOSE--Retrospective analysis of 5069 patients with abdominal trauma treated at the Department of Surgery University of São Paulo School of Medicine over a six-year period from 1986 through 1991. METHODS--Forty five patients with gallbladder and extra-hepatic ducts injury were identified (0.89%) and divided in two groups according to the nature of trauma: 12 caused by non-penetrating injuries and 33 to penetrating injuries. Records, including operative and pathology reports, were reviewed to study the site of injury, associated intra-abdominal injuries, incidence, trauma scores, treatment, morbidity, mortality rates and correlated with the nature of the trauma. RESULTS--Overall mortality was 24.4%. The incidence was greater in patients sustaining penetrating abdominal trauma (p < 0.05). Forty of the 45 patients (88.9%) had liver lacerations, the most commonly seen injuries. The patients with blunt abdominal trauma had significant different trauma scores (p < 0.05) than those with penetrating trauma, indicating greater severity in this group of patients. CONCLUSION--There is a relation between severity of trauma and incidence of extra-hepatic biliary tract injury. However, in the penetrating trauma, the incidence of trauma is correlated with the direction of the wound and there is no relation with the severity of trauma. The greater mortality seen in the patients sustaining non-penetrating injury (p < 0.05) supports this observation.
With the aim of aiding the accurate diagnosis and treatment of patients with pancreatic injuries, we reviewed the medical records of sixty-five patients, treated for traumatic pancreatic lesions at the Department of Surgery of the University of São Paulo in the 5-year period from 1989 through 1993. Records, including operative and pathology reports, were reviewed and the location of the pancreatic injury, associated intra-abdominal injuries, type of injury, trauma scores, treatment, complications and mortality rates recorded. There were 58 male and seven female patients with a mean age of 28.3 years (range, 2-77 years). Of the 65 pancreatic injuries, 45 (69.2%) were caused by penetrating wounds and twenty by blunt trauma. The most frequent site of lesion was the head of the pancreas (38.5%). Associated injuries were found in all but five of the patients. In the 65 patients, 170 intra-abdominal injuries were found (2.6 per patient). Twenty-eight of the 65 patients (43.1%) had liver lacerations. Lacerations of major abdominal vessels (27 patients), gastric lacerations (25 patients) and colorectal lacerations (17 patients) were the next most frequent injuries. Fifteen out of twenty patients died within two days after the accident from severe concomitant injuries. Simple drainage was performed in 33 patients, distal pancreatectomy in 17 and duodenopancreatectomy in six patients. Pancreas-related complications occurred in 20 (30.7%) out of 57 patients who survived the initial operation. We concluded that the type of repair employed in our series was related to the class of injury and clinical conditions (based on trauma scores). Therefore, whenever possible, conservative management (no pancreatic resection) was employed in patients that sustained class I and II injuries and pancreatic resection in class III and IV injuries.
The majority of cystic lesions of the pancreas are pseudocysts. Nine to thirteen per cent of pancreatic cyst are neoplastic, benign or malignant. Failure to recognize neoplastic nature of a cyst leads to an improper management. The authors present five cases of cystic tumors mistaken for pancreatic pseudocysts, including three mucinous cystadenomas and two mucinous cystadenocarcinomas. Four were drained by cystojejunostomy and one cystogastrostomy. One patient with no metastases at first operation had metastatic spread at reoperation. In the other four cases, subsequent resection was possible and probably curative. Review of the literature and guidelines are given for the purpose of differential diagnosis between theses entities.
Cystic neoplasms are an uncommon group among pancreatic tumors. These lesions are seen more frequently in recent surgical practice, probably because of advances in diagnostic and surgical techniques. We report 24 patients with cystic tumors of the pancreas, including twelve patients with serous cystadenoma, ten with mucinous cystadenoma and two patients with mucinous cystadenocarcinoma. Twenty-two patients were women and two were man. The median age of patients was 53.5 years (range, 21 to 80 years). Mild abdominal pain was the main symptom; in 71% of patients and weight loss in 29% of patients. The lesions were incidental findings 8% of patients. The mean size of the cysts was 7.8 cm (range, 2.3 to 15cm). Eleven cystic neoplasms were located in the head, three in the neck, five in the body, two in the tail of pancreas and three in the body and tail. All patients underwent surgical exploration. There was no perioperative mortality. Total tumor resection provides the best chance of cure and may remove the risk of malignant transformation of the cystadenomas, particularly of the mucinous type.
Esophageal webs are an uncommon group among esophageal diseases. We report our findings in ten patients with membranes in the upper esophagus; seven of them were women. The median age was 48.5 years (range 24 to 73 years). Dysphagia was the main symptom in all patients and anemia was found in six cases. Radiologic and endoscopic studies provided the diagnosis. All patients underwent endoscopic dilatation and/or debridement and good results with this management were achieved. A review of literature of this condition and a discussion about the diagnosis, treatment and etiopathogenesis are presented.
Pseudotumoral form of gastric ulcer is an infrequent clinical presentation of peptic disease. We present the findings in ten patients with this variety of gastric peptic ulcer treated in the last five years. All records including preoperative radiological and endoscopic examinations are reviewed. Five patients were women and five were men. The median age of patients was 62.1 years (range, 45 to 79 years). Epigastric pain was the main symptom in 90% of patients and weight loss in 70%. Six patients underwent surgical treatment. There was no perioperative mortality. A review of literature of this condition and a discussion about the differential diagnosis are presented.
Gastrointestinal hemorrhage continues to be a major medical problem. Even with improvements in both diagnostic and therapeutic, a significant number of patients still require surgical intervention for control of hemorrhage. When the source of persistent lower gastrointestinal hemorrhage is unknown, subtotal colectomy is a conceptually rational management choice. The authors present a case of massive lower gastrointestinal hemorrhage with unusual fatal outcome. A review of literature of this condition and a discussion about the diagnosis, treatment and etiopathogenesis are presented.
Gallbladder lesion is infrequent, occurring in approximately 0.5 to 8.5% of all patients with blunt and penetrating abdominal trauma. The incidence of gallbladder injury in such cases is low. This study reviewed 32 patients with gallbladder injury due to abdominal trauma over a 6-year period to determine the complications, associated injuries, and mortality rate.
Liver cell adenomas were relatively rare until the use of oral contraceptives. Most of these tumors have occurred in otherwise healthy young women who have been exposed to oral contraceptives. The treatment of this condition remained controversial for a long time. However, bleeding is still a frequent complication and can lead to a significant mortality rate. The better surgical results in hepatic resection, due to technological advances, has contributed to the indication of surgical management as therapeutic option in hepatic cell adenoma. Some authors believe that liver cell adenomas were potentially premalignant and could degenerate into hepatocellular carcinoma but there is very few well documented reports of this transformation. We report our experience in the management of liver cell adenoma.
Rupture of the diaphragm from blunt trauma is uncommon, but greatly improved prehospital care and transportation of victims has increased the frequency at which patients who sustain this injury arrive at the emergency room alive. We report a case of bilateral diaphragmatic rupture from blunt abdominal trauma in a 33-year old man. Diagnosis was established by laparoscopy after suggestive chest X-rays, liver scintigraphy, CT scan and magnetic resonance imaging. The methods used to diagnose this condition are analyzed.
The emergency surgical treatment of severe hepatic traumas still carries a high mortality risk. We report a case of severe blunt trauma to the liver managed without surgery under CT guidance. This attitude requires haemodynamic stability of the patient, close monitoring in a surgical intensive care unit and repeated CT scans. Laparoscopy was used to the management of hemoperitoneum due to rupture of hematoma and diagnosis and treatment of bile leakage. Conservative treatment is a reasonable option in selected hemodynamically stable patient with severe hepatic trauma.
Buccopharyngeal motor disorders causing difficulties in swallowing are frequently encountered in clinical medicine. Affected patients manifest distinctive clinical features and pose special problems in their management. A case report is described and summarize the pathogenesis, consequences, evaluation, treatment and some selected clinical conditions that are associated with buccopharyngeal dysphagia.
Reconstructive of complex chest wall defects following infected sternotomy represents a surgical challenge. Several options were described for these defects reconstructions, using muscles flaps and omentum which provided obliteration of dead space and coverage. We present a reconstruction of a major chest and abdominal wall defect in a 62-year old patient, who had mediastinitis, osteomyelitis and necrosis of sternum after myocardial revascularization. The pectoralis major was used unsuccessfully, with total loose of the flap. After wound failure, a flap of omentum based on the left gastroepiploic vessels was obtained by a laparoscopic surgery, with no complication. The omentum was translocated through the defect that reached the abdominal wall covering the defect and allowing the use of split-thickness grafts. The laparoscopic procedure showed advantages over the laparotomy in the management of omentum, with the same results in the reconstruction of the defect added the advantages of a minimal invasive procedure, mainly in patient with bad clinical conditions.