[Endoscopy of the upper digestive tract by nasal approach: preliminary study with a pediatric endoscope].
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Adolescent↗
Biomedical subjects
T Ponchon
Publications and source records attributed to T Ponchon.
Increased chemocytotoxicity to colon cancer cells by shock wave-induced cavitation.
BACKGROUND/AIMS: Cavitation has been shown to hinder colon cancer cell proliferation in vitro. This study aimed at investigating the interest of combining cavitation and cytotoxic drugs in vitro. METHODS: HT-29 cells were exposed in suspension to cavitation (shock waves plus bubbles) before 5-fluorouracil (FUra) administration. Cytotoxicity was studied by means of clonogenic survival, cell proliferation by [3H]deoxyuridine ([3H]dUdR) incorporation, and influence of the treatments on the cell cycle by cytofluorimetry; the effects of cavitation on RNA incorporation of FUra, cell permeability, and activity of thymidilate synthetase (TS) were also studied. RESULTS: A preliminary exposure to cavitation (as compared with FUra alone) induced decreased colony formation (by up to 2 log in certain conditions) and colony size. Cavitation alone induced increased incorporation of [3H]dUdR during 48 hours and stimulated TS activity, but in the presence of FUra, the concentration of the drug that causes 50% inhibition of control cell growth for [3H]dUdR incorporation was reduced by up to 1 log, and TS inhibition was increased after cavitation as compared with FUra alone. RNA incorporation of [14C]FUra was increased by cavitation, as a consequence of altered cell permeability rather than a direct RNA effect. Seventy-two hours after treatment, cavitation plus FUra decreased by more than 50% the S-phase fraction and also inhibited mitosis. CONCLUSIONS: Submitting HT-29 cells to cavitation before treatment by FUra significantly increases the effects of the drug. The action of both agents appears to be partially synergistic with a cycle specificity.
Air↗
Endoscopic ultrasonography in the preoperative staging of esophageal cancer.
Endoscopic ultrasonography is the best available method for the locoregional staging of esophageal carcinoma. Its main limitations are represented by a) tumor stenosis, b) distinguishing between malignant and benign lymph nodes, and c) distinguishing between mucosal and submucosal cancer. In untreated esophageal carcinoma, three main groups can be distinguished, based on clinical and morphological evaluation (endoscopy, abdominal ultrasound and CT). EUS is not useful when palliative treatment aiming to relieve dysphagia is the only treatment. In tumors with a superficial pattern at endoscopy, EUS is necessary to distinguish T1 from more invasive tumors, but endoscopic treatment (photodynamic therapy, strip biopsy) is indicated only in nonsurgical patients. In the last, and largest, group of tumors with no clear surgical contraindication, EUS is necessary when surgery is not the only treatment considered. EUS staging then improves patient management (surgery alone, surgery with preoperative treatment, or nonsurgical treatment; type of surgery). Moreover, it provides a good evaluation of the prognosis, and allows better follow-up after nonsurgical treatment.
Esophageal Neoplasms↗
Focused liver ablation by cavitation in the rabbit: a potential new method of extracorporeal treatment.
A new device was used to achieve focused tissue ablation by shockwave induced cavitation. The device produced a half cycle of negative pressure followed by a shock wave, thus enhancing cavitation. Twenty eight New Zealand rabbits were treated. Therapeutic ultrasound was targeted at the centre of the liver under ultrasound guidance. The focal volume was scanned with a computer operated x-y-z micropositioner. The number and frequency of bursts as well as the distance between two x-y-z displacements were preselected. The relation of tissue ablation seen to preselected parameters, effects on surrounding tissues, biological side effects, and mode of healing were studied. Macroscopy, planimetry, and quantitative microscopy were used. Focused and homogeneous tissue ablation was achieved within well defined limits. Maximal tissue ablation was seen in the centre of the target. Liver surrounding the target remained unaffected. Lesions were made of a-cellular spots surrounded by disorganised rims of necrotic hepatocytes; 24 hours after treatment, the changes (mean (SEM)) in alanine transaminase and haemoglobin were +225 (36)% and -2.4 (2)% respectively. Serum transaminases, haemoglobinaemia, and packed cell volume were normal 21 days after treatment and the target area was replaced by a fibrous scar. It is concluded that ultrasound cavitation may achieve extracorporeal intrahepatic tissue ablation inside a predetermined target. This technique should now be tested in an animal hepatic tumour model.
Alanine Transaminase↗
[Treatments of biliary fistulas following the removal of a Kehr tube after orthotopic liver transplantation].
Biliary tract complications are a major source of morbidity after liver transplantation. From October 1990 to September 1992, 77 patients, including 13 children and 64 adults, received 80 liver transplants. Biliary reconstruction was performed using a choledochocholedochostomy with a T-tube in 40 recipients. We report the management of bile leaks following T tube removal in 6 patients. In all cases, bile leak was diagnose by ultrasound examination requested for abdominal pain. In the first 2 patients, a surgical treatment was applied: Roux-en-Y choledochojejunostomy was performed on the first patient and simple suture of the fistula in the second patient. Two patients were managed nonoperatively using endoscopic and radiological procedures allowing placement of bile duct prosthesis and abdominal drainage. In 2 patients with small localized sub-hepatic collection, no surgical or radio-endoscopic treatment was attempted; spontaneous resolution of the collections was achieved in 2 months on ultrasound examination. All patients are alive, although, the patient who was operated on with a roux-en-Y choledochojejunostomy developed thrombosis of the right hepatic artery and biliary anastomotic stenosis which required further operations. We advocate endoscopic placement of endobiliary prosthesis and percutaneous biliary drainage as first-line therapy for significant fistula after T-tube removal. The use of choledochocholedochostomy without a T-tube when possible for biliary reconstruction in liver transplantation could be an effective procedure, but requires further evaluation.
Adult↗
Pancreas and ampulla of Vater.
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Ampulla of Vater↗
[Common bilio-pancreatic channel. Apropos of a case with intermittent dilatation of the biliary tracts].
BACKGROUND: A common biliopancreatic channel can be revealed by cholestatic episodes. Its early removal avoids the development of liver cirrhosis and the risk of carcinomatous change. CASE REPORT: A 2 year 9 month-old girl had suffered from jaundice plus dark urine and pale stools for 2 months. A similar episode occurred 7 months later. Ultrasonography showed moderate dilatation of the intra and extrahepatic bile ducts that disappeared a few weeks later. A third episode of cholestasis with moderate dilation of the bile ducts occurred at the age of 3 year 11 months, complicated 2 weeks later by abdominal pain, vomiting and abdominal distension. Her serum amylase activity was 1,380 IU/l (N < 82). Ultrasonography and CT scan showed moderate dilation of the common hepatic duct. Liver biopsy showed pathological features consistent with bile obstruction. Endoscopic retrograde choledocopancreatography showed a long common channel with dilated extra and intrahepatic bile ducts, an incomplete pancreas divisum and numerous intracanalar stones. A sphincterotomy was performed and stones were extracted. The patient is well 18 months after surgery, with normal laboratory and ultrasonographic profiles. CONCLUSION: A common biliopancreatic channel is often associated with choledocal cyst. Whether development of the cyst is preceded by intermittent dilation of the bile ducts, as in this case, remains to be determined.
Bile Ducts↗
Characterization of extracorporeal ablation of normal and tumor-bearing liver tissue by high intensity focused ultrasound.
Treatment parameters of extracorporeal high intensity focused ultrasound (HIFU) were analysed in normal and tumor-bearing rabbit liver. HIFU was generated with a 1 MHz transducer and energy was provided by a 7.5 kW power amplifier. In vivo experiments were conducted on 74 New Zealand rabbits. Normal rabbits and rabbits bearing an intrahepatic VX2 tumor were used. In group 1, spatial peak temporal peak (SPTP) intensities ranging from 1470 to 5500 W cm-2 and exposure times from 0.5 to 5 s were tested at a constant depth in the liver; in group 2, the output power was adjusted as a function of the target depth in order to keep constant the focal in situ intensity in the liver; in group 3 (liver tumors), the focal in situ intensity was 1365 W cm-2 in eight rabbits and 500 W cm-2 in nine. In groups 1, 2 and 3, rabbits were sacrificed 48 h after the treatment. Groups 4 and 5 were designated for analysis of the lesion in the normal liver 4 weeks after treatment at 1000 W cm-2 and 3000 W cm-2 SPTP intensities, respectively. In normal rabbits, the lesion volume increased with exposure time at constant intensity; there was a negative correlation between intensity and exposure time (group 1). When the output power was adjusted as a function of the path length, the lesion size was nearly constant (group 2). In VX2 rabbits, tumor destruction rates were significantly higher in rabbits treated at 500 W cm-2 than in rabbits treated at 1365 W cm-2 (p < 0.05; group 3). As in the normal liver, the lesion volume increased with the exposure time at constant intensity. HIFU lesions treated at 1000 w cm-2 (SPTP) healed as thin fibrous scars, and no severe complication occurred (group 4); at 3000 W cm-2 (SPTP), scars were larger and perforation of a neighbouring organ was seen in 7 of 11 rabbits (group 5).
Animals↗
In vivo effects of cavitation alone or in combination with chemotherapy in a peritoneal carcinomatosis in the rat.
Cavitation (volume oscillations and collapse of gas bubbles), as generated by a co-administration of shockwaves (SW) and microbubbles (SWB), induces cytotoxicity in vitro. Moreover, cavitation potentiates the effects of Fluorouracil (FUra) on colon cancer cells. We aimed at reproducing such effects in vivo. A peritoneal carcinomatosis was induced in BDIX rats by intraperitoneal (IP) injection of DHDK12PROb cells. Cavitation was produced by various SW regimens (250 to 750SW) combined with bubbles (air/gelatin emulsion) infused through an IP catheter. In two consecutive experiments, microtumours (day 3 after cell injection) were submitted to various combinations of cavitation and/or Fluorouracil (FUra) and Cisplatinum (CDDP) at either high or low doses. After 30 days, 100% of control animals were dead or presented carcinomatosis with ascites, vs 60% after FUra 5 mg kg dy, day 4 through 8, and 0% after 250 SWB, day 4 and 6 + FUra 5 mg kg dy, day 4 through 8 (P < 0.001); similar differences were found with CDDP. Survival after low dose FUra + SWB was comparable to high dose FUra (25 mg kg dy day through 8) and was improved as compared to low-dose FUra alone. Only a high dose FUra + SWB schedule induced 40% long term (> 150 days) disease-free survival, but also a higher undesirable toxicity (40% toxic deaths within 1 month). It is concluded that cavitation is cytotoxic in vivo and that it potentiates the effects of FUra and CDDP in this animal model.
Animals↗
Echoendoscopy prior to endoscopic tumor therapy--more safety?
Echoendoscopy has been found useful to better define gastrointestinal tract tumors which may be suitable for endoscopic treatment. In benign tumors, echoendoscopy may be used to decrease the risk of hemorrhage or perforation before resection of large polyps or submucosal lesions. The most important indications for echoendoscopy, however, are in the field of GI oncology, and the method may lead to a better selection of superficial cancers without lymph node metastases. However, endoscopic ultrasound is still limited in differentiating mucosal from submucosal tumors and in the detection and interpretation of small lymph nodes. Technical improvements and careful interpretation of echoendoscopy will increase the number of patients cured by non-surgical procedures in the future.
Colorectal Neoplasms↗
Cytotoxic effects of acoustic cavitation on HT-29 cells and a rat peritoneal carcinomatosis in vitro.
Damage to cells and tissues exposed to shock waves (SWs) is thought to be secondary to cavitation phenomena involving the collapse of gas bubbles in a fluid. Using HT-29 cells and DHDK12PROb tumors, we tried to enhance SW-related damage by the simultaneous administration of gas microbubbles. Bubbles resulted from a mixture of air and gelatin (HT-29 cells) or from a carbonated NaCl solution (tumors). HT-29 cells in suspension received either SW (50, 250, or 1000 SWs) alone or in association with bubbles. Trypan blue-negative cells decreased as the number of SWs increased. Exposure to SWs and bubbles resulted in not only an increased but also a delayed mortality as compared to SWs only. One thousand SWs with bubbles induced a complete inhibition of cell growth, with cytoplasmic vacuolae, ruptured membranes, and abnormal nuclear shape and chromatin. Exponential and confluent cells exhibited a similar mortality and growth. DHDK12PROb tumors received either SWs only (50, 100, 250, 500, or 1000 SWs) or SWs with bubbles in vitro. Thymidine incorporation was significantly lower after exposure to SWs with bubbles as compared with controls and SWs only; it was nil by 1000 SWs with bubbles. Histopathological features of tumors exposed to SWs with bubbles included erosion and hemorrhage, disorganized structure, pyknotic nuclei, and cytoplasmic vacuolae. We conclude that cavitation, as produced by a combination of SWs and gas microbubbles, can achieve bioeffects which are relevant to cancer therapy.
Animals↗
Percutaneous fine-needle aspiration cytologic study of main pancreatic duct stenosis under pancreatographic guidance.
When pancreatography shows a stenosis of the main pancreatic duct in patients with normal or inconclusive ultrasound and computed tomography, the exact nature of such stenosis is sometimes difficult to precise before surgical exploration. In such cases, the authors systematically performed a percutaneous fine-needle aspiration cytologic study of the stenosis under pancreatographic guidance. Fifteen patients were referred because of suspected pancreatic malignancy. The tumor markers, carcinoembryonic antigen (CEA) and CA 19-9 were normal in 11 patients and elevated in one patient, whereas only CA 19-9 was elevated in three others. In 14 cases, both the ultrasound and computed tomography did not show any obvious pancreatic mass. The pancreatography was done through endoscopic retrograde cholangiopancreatography (ERCP) (12 patients) or percutaneously in case of failure at ERCP3 and showed a main pancreatic duct stenosis that underwent aspiration by percutaneous fine needle precisely positioned using biplane fluoroscopy. The aspirated material was then smeared on glass slides, air-dried, and stained by Giemsa. In nine of the 15 patients, cytologic study revealed adenocarcinoma. This was confirmed by surgery in five and by progressive deterioration followed by death in four. In six patients, cytologic study gave a nonmalignant result. Chronic pancreatitis was found in five of them, confirmed at surgery in three and based on uneventful follow-up of at least 12 months in two others. In one case, a pancreatic adenocarcinoma not detected by cytologic study was found at surgery. Thus, the sensitivity and specificity of this diagnostic approach were 90% and 100%, respectively. No serious complication was noticed. The authors conclude that when ultrasound and computed tomography are inconclusive, percutaneous fine-needle aspiration cytologic study of main pancreatic duct stenosis under pancreatographic guidance is a safe, simple, and helpful procedure in the investigation of patients with suspected pancreatic malignancy.
Adenocarcinoma↗
Physicochemical determinants of in vitro shock-wave biliary lithotripsy.
Human gallstones were studied by visual inspection, computerized tomographic imaging, and chemical analysis to assess physicochemical characteristics that may determine the outcome of in vitro shock-wave fragmentation. Eighty-five stones (mean diameter: 13.2 +/- 5 mm) were each collected from different patients. Fifty-five (65%) calculi were angular and 30 (35%) round or oval-shaped. Three easily obtained measures were derived from each stone's optimal computerized tomographic image including the mean stone density, a measure corresponding to the standard deviation of the mean stone density value which we termed the stone density distribution index and which may reflect the physicochemical heterogeneity of a given gallstone, as well as the density range. After the administration of 2500 shock waves using an electrohydraulic generator, fragmentation was noted in 68 calculi (80%) and was satisfactory in 27 (32%) (where the largest resulting fragment diameters were all less than or equal to 5 mm). Strong determinants of satisfactory fragmentation on multivariate analysis included a stone diameter of less than or equal to 15 mm, the presence of an angular stone shape, and a stone density distribution index of greater than or equal to 60 Hounsfield units. The other parameters did not independently determine satisfactory fragmentation. Prospective clinical trials are needed to assess whether these findings result in a better prediction of the success of extracorporeal biliary lithotripsy and a broadening of its indications.
Chemical Phenomena↗
Pulsed dye laser lithotripsy of bile duct stones.
Efficacy and safety of pulsed dye laser lithotripsy was tested in 25 consecutive patients in whom bile duct stones could not be extracted after endoscopic sphincterotomy. The patients had one to six (mean, 1.8) bile duct stones (diameter, 10-35 mm; mean, 18 mm) located in the common bile duct (18 cases), the intrahepatic bile ducts (6 cases), or in a long cystic duct stump (1 case). Different approaches were tested depending on the presence of a T tube and on the localization of the bile duct stones. When a T tube was present (7 cases), the lithotripsy was performed under direct vision using a choledochoscope inserted through the T-tube tract. In 18 patients without a T tube in place, the lithotripsy was performed under fluoroscopy using a retrograde approach in case of common bile duct stones (14 cases) or under choledochoscopy using a percutaneous transhepatic approach in case of intrahepatic bile duct stones (4 cases). Fragmentation of all the bile duct stones and a complete bile duct clearance were obtained in all 11 cases with procedures performed under direct vision as compared with only 5 of 14 cases with procedures under fluoroscopic control. Moreover, 6 of the 9 failures using the latter approach were offered another session using a choledochoscope inserted through a percutaneous transhepatic tract and were also successfully treated. No complication related to the laser beam was noted. It is concluded that pulsed dye laser lithotripsy of bile duct stones (that are unable to be removed by standard endoscopic techniques) is safe and efficacious provided that it is performed under direct vision. Technical refinements are needed before this procedure can be reliably performed under fluoroscopy.
Aged↗
Extracorporeal lithotripsy and oral bile acid dissolution of gallstones: the Lyon experience.
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Chenodeoxycholic Acid↗
Hepatic lesions in the rabbit induced by acoustic cavitation.
Tissue damage during shock-wave lithotripsy is presumably secondary to cavitation phenomena involving the collapsus of gas bubbles in a fluid. To enhance shock-wave-related hepatic lesions, intravascular gas microbubbles were administered. Three groups of eight rabbits each received either 500 shock waves focused on the right hepatic lobe (group 1), gas microbubbles as a mixture of 50 cm3 of air with 50 cm3 of gelatin infused through an arterial catheter (group 2), or 500 shock waves and gas microbubbles simultaneously (group 3). In group 1, two animals had two to three subcapsular hepatic hematomas (diameter, less than 5 mm) and five had one to five intraparenchymal hematomas (less than 1 mm). In group 2, a moderate liver congestion was observed in three animals. In group 3, all animals had numerous subcapsular and intraperenchymal hematomas (2-30 mm). The hematomas were centered around the portal spaces, associated with lacunae (0.5-5 mm in diameter). Hematomas were also present on the anterior wall of intraabdominal organs. It was concluded that intravascular infusion of gas microbubbles into the path of a shock-wave generator dramatically enhances tissue damage. This technique, potentially useful in the treatment of hepatic tumors, needs refinement to confine lesions in a more uniform pattern to the targeted parenchyma.
Animals↗
Extracorporeal biliary lithotripsy. Review of experimental studies and a clinical update.
PURPOSE: To identify the technical and physical principles of extracorporeal biliary lithotripsy that are clinically relevant, and to review the patient series published to date. DATA IDENTIFICATION: Studies published since 1983 identified through a computerized search of MEDLINE and extensive hand searching of bibliographies in identified articles. STUDY SELECTION: Twenty-nine studies done in vitro or in animals and 21 studies in humans assessing biliary lithotripsy. DATA EXTRACTION: Based on an understanding of experimental determinants of fragmentation, we assess and explain the differences in the results from the clinical studies. The conclusions concerning overall clinical efficacy and safety are emphasized. RESULTS OF DATA ANALYSIS: Extracorporeal shock waves will safely fragment the gallstones of 80% to 100% of selected patients. However, the rate of satisfactory fragmentation (defined as the persistence of fragments only 3 to 5 mm in diameter or less) varies widely among the studies (22% to 78%); this discrepancy depends partly on differing characteristics of stone populations. For patients presenting with solitary stones of 20 mm in diameter or less, 90% will be stone-free within 6 to 9 months after lithotripsy; moreover, the success of lithotripsy determines the rapidity and extent of fragment dissolution. Bile-duct-stone lithotripsy is reserved for patients in whom endoscopic stone extraction and intracorporeal lithotripsy, with or without direct contact dissolution, have failed. Lithotripsy achieves ductal clearance in 55% to 85% of patients. CONCLUSIONS: Extracorporeal lithotripsy is safe and effective in selected patients, and has a definite role to play in managing patients with biliary stone disease. Its role in the coming years will depend on technical improvements in the generators, a tailored approach to complementary dissolution or extraction, and effective prophylactic therapy for preventing gallstone recurrence.
Animals↗
Extracorporeal lithotripsy of bile duct stones using ultrasonography for stone localization.
In 19 patients, extraction of bile duct stones through the papilla using a Dormia basket or a mechanical lithotripter was not possible following endoscopic sphincterotomy. After the insertion of a nasobiliary drain, extracorporeal lithotripsy was performed with intravenous sedation using an ultrasonographic stone localization system. The number and location of stones were first determined by retrograde cholangiography. At the time of lithotripsy, saline was injected in the bile ducts to modify the acoustic impedance of tissues surrounding the stones, and subsequent ultrasonography was effective in localizing all stones present in 4 of 5 (80%) patients with intrahepatic stones, and 13 of 14 (93%) with common bile duct stones. In 10 patients (53%), fragmentation was satisfactory and the bile ducts were cleared completely. The mean single stone diameter was significantly smaller in successful cases of fragmentation compared with failures (22.8 +/- 6.6 mm vs. 40 +/- 10 mm). The results in patients with multiple stones were significantly worse than those in patients with single stones of similar size (25% vs. 100% successful fragmentation). Reasons for this difference in results included the small size of the focal area and the reduced ability of ultrasonography (1) to adequately visualize multiple calculi individually and (2) to assess the degree of stone destruction. Care was taken to first await the resolution of infection or the correction of coagulation abnormalities when present; no morbidity following extracorporeal lithotripsy was observed. Despite its 3-step approach (endoscopic sphincterotomy, lithotripsy, and endoscopic extraction), the need for only intravenous sedation and the absence of patient immersion in water render this technique attractive for elderly and frail patients.
Adult↗