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Biomedical subjects

J Danis

Publications and source records attributed to J Danis.

At least 19 recordsLinked to original sources
PubMed2005

Laparoscopic azygoportal disconnection procedure with a bipolar feedback controlled sealing system in a porcine model.

BACKGROUND: To examine the feasibility of a new, minimally invasive procedure for the devascularization of the proximal stomach and distal esophagus to prevent recurrent variceal bleeding in portal hypertension in a new animal model. MATERIAL AND METHODS: Portal hypertension was created by laparoscopic clip ligation of the portal vein on 20 pigs. After 2 weeks the azygoportal disconnection procedure was performed with the LigaSure-ATLAS instrument. RESULTS: There were 16 pigs out of 20 that survived both operations. Two died during introduction of anesthesia, one because of a cardiac arrest (second operation). One pig died resulting from necrosis of the gastric and esophageal wall. Autopsy (2 weeks later) showed that there was a complete arterial devascularization. At autopsy, none of the remaining 16 pigs had esophageal varices or necrosis of the stomach or esophagus. CONCLUSION: Laparoscopic azygoportal disconnection is a less invasive method for the prevention of rebleeding and seems to be safely performed with the LigaSure-ATLAS instrument.

Animals↗
PubMed2005

Short- versus long-sequence MRI cholangiography for the preoperative imaging of the common bile duct in patients with cholecystolithiasis.

BACKGROUND: This study aimed to compare an 18-s fast spin echo magnetic resonance image sequence (coronal thick-section two-dimensional breathhold) with a three-dimensional axial and coronal thin-section sequence and its secondary reconstruction, and to assess its value in the diagnosis of bile duct pathologies, particularly common bile duct stones (CBDS) before laparoscopic cholecystectomy. METHODS: This study prospectively included 72 patients. Because of protocol violations, 14 of these patients had to be excluded. Thus, 58 patients (29 Man and 29 women with a mean age of 51 years) who had cholecystolithiasis or suspected choledocholithiasis were evaluated. Magnetic resonance cholangiopancreatography (MRCP) was performed for all patients with a fast sequence (18 s) and a long sequence (coronal oblique and axial respiratory triggered; 16 min). Two radiologists, blinded with respect to diagnosis, evaluated all the radiographic images. The MRCP results were confirmed for all the patients: 20 by endoscopic retrograde cholangiopancreatography, 46 by intraoperative cholangiography, and 2 by percutaneous transhepatic cholangiography. RESULTS: According to the findings, 16 patients (28%) had CBDS, 6 patients (10%) had common bile duct stenosis, and 36 patients (62%) had a clear bile duct. With regard to CBDS, the short sequence had 100% specificity, 94% sensitivity, and an overall accuracy of 98%. Its negative predictive value was 98%, and its positive predictive value was 100%. The long sequence had a specificity of 100% and a sensitivity of 100%. CONCLUSION: Because of its high sensitivity and specifity, MRCP has the potential to be the diagnostic method of choice for CBD evaluation. The short sequence is not suitable for the diagnosis of all CBD pathologies, but in cases of suspected CBDS, more than 80% of the patients could be diagnosed correctly, and the complete sequence could be dropped.

Cholangiopancreatography, Magnetic Resonance↗
PubMed2004

Novel technique of laparoscopic azygoportal disconnection for treatment of esophageal varicosis: preliminary experience with five patients.

BACKGROUND: Liver cirrhosis leads frequently to the development of ascites and a formation of varicose veins in the esophagus. The latter presents increased mortality risk. Recently, significant progress in laparoscopic technology enabled devascularization of the proximal stomach in a less invasive way. The results experienced by five patients are presented. METHODS: Laparoscopic azygoportal disconnection was performed by means of novel technique (Danis procedure) in five men with esophagus varices bleeding (2nd to 11th events) and liver cirrhosis stage Child-Pugh B and C. This procedure was performed after all other methods had either failed to prevent recurrent bleeding or were refused by the patient. Five ports were positioned on the upper abdominal wall. The veins in the lesser omentum were divided by means of the LigaSure-Atlas device. The stomach coronary vein was visualized, and all the proximal branches toward the esophagus as well as the short gastric vessels were divided. The diaphragm hiatus was opened, and the distal esophagus was dissected. The paraesophageal venous collaterals also were divided, and the remaining varicose veins of the esophagus were interrupted by transmural stitching. RESULTS: All the patients survived the minimally invasive procedure. Two of them died 9 and 16 months after surgery, respectively, because of liver insufficiency. No bleeding event from varicose veins in the esophagus occurred postoperatively. CONCLUSION: Laparoscopic azygoportal disconnection is a less invasive method for prevention of rebleeding from varicose veins in the esophagus. Further studies are necessary to confirm these preliminary results.

Adult↗
PubMed2002

Laparoscopic resection of an accessory spleen in a patient with chronic lower abdominal pain.

During a diagnostic laparoscopy in a patient with chronic lower abdominal pain we found a pediculated accessory spleen (AS) near the left adnex. The pedicle was dissected by ultrascision, it was cut by an Endo GIA, and the AS was extracted. AS occurs in 25-40% of the population. They are always situated on the left side: hilum of the spleen, splenic artery, pancreas, splenocolic ligament, greater omentum, mesenterium, adnexal region, and scrotum. In most cases they are asymptomatic. In hematological disorders they can take over the function of the original spleen after splenectomy. Sometimes, AS can mimic tumors in other organs, such as pancreas, kidney, or liver. Likewise, there are descriptions of AS in the scrotum, the spermatic cord, the adnexes, the uterus, the stomach, the small intestine, or the heart. In rare cases they can cause pain because of cysts, abscesses, hemorrhage, or spontaneous rupture. In acute pedicle torsion an infarction can be caused presenting as acute abdomen, which is most often seen in young patients. In our case the pain was caused by pedicle torsions or mechanical irritation of the adnex. The cause of the changing localization of the pain was the long pedicle. In describing this case, we point out the advantage of diagnostic laparoscopy in patients with chronic lower abdominal pain.

Abdomen, Acute↗
PubMed1998

The effect of contrast variation on task performance in video evaluation.

BACKGROUND: Luminosity and brightness of the organs viewed on the screen are important for orientation during teleoperating. They can impair the precision of our orientation ability. METHODS: The way in which organs scatter light during laparoscopic operation was detected and analyzed by means of reflection spectrophotometry with the Photoshop program package (ADOBE). The arithmetical skill was measured during different illumination conditions of the screen created randomly, using values of the liver, gallbladder, and omental fat. RESULTS: Separate human tissues and organs could be divided on the basis of their luminosity into three basic groups: the luminous tissues such as fat, the stomach, and the bowel; medium-luminous organs such as diaphragm and gallbladder; and dark, mostly parenchymatous organs such as the liver and the spleen. The most luminous tissue illuminated the screen intensely. In experiments the hyperillumination impaired arithmetical skills of 15 volunteers. The errors appeared constantly and the time needed to count the generated points was significantly longer when 40% of intensively illuminated view was exceeded. CONCLUSIONS: A situation may occur wherein the imaging system lacks the capacity to transmit needed optical information. Intense brightness of the screen may suppress surgical skills during teleoperating. Critical limit was achieved in our experiment with 40% of the view illuminated by omentum fat. This limit can be important for robotic surgical systems such as automated robotic camera control.

Adipose Tissue↗
PubMed1996

Theoretical basis for camera control in teleoperating.

BACKGROUND: The triangle paralaxis method for camera control in teleoperating is presented. METHODS: For orientation in the 3D space of the corporic cavity there are three points necessary for the creation of the paralaxis triangle. This triangle is then imagined and compared with topography during surgery. The first and second points are created in one's mind at the locus of the entry of the instruments into the viewing field of the camera. The third apex of the triangle is the area of dissection-the point in which the instruments converge. The fourth point to be viewed determines the course of dissection. Triangle paralaxis may be applied in dissection with only one instrument as well as in the zooming technique, closely viewing a part of the dissecting instrument. RESULTS: Using this technique a 7.78% rate of conversion and 2.15% rate of reoperation could be achieved in 334 evaluated laparoscopic cholecystectomies performed in a small public hospital. CONCLUSIONS: Triangle paralaxis seems to be a simple method for ensuring an optimal camera view during laparoscopic surgery.

Austria↗
PubMed1994

In vitro and in vivo viability assessment of unpurified pancreatic islet tissue.

The viability of porcine collagenase-prepared islet preparations (n = 16) was classified by 31P-NMR spectroscopy, staining by neutral red and trypan blue, and in vitro insulin secretion following glucose challenge. Vital islets exhibited a phosphate diester/phosphate monoester (PDE/PME) ratio of 0.5-0.9, a staining score of 18-30 and an insulin secretion responding well to glucose challenge. Damaged islets performed at a PDE/PME of 0.2-0.49 and a staining score of 9-17 and necrotic islets had 0.0-0.49 and a staining score of 9-17 and necrotic islets had 0.0-0.19 and 0-8, respectively. The islets of the latter two groups did not adequately respond to glucose. The in vivo function following autotransplantation of these islets into the spleen was investigated in five recipients of more than 3000/kg vital islets of which 4 expressed daily normoglycemia (< 200 mg%), normalized intravenous glucose tolerance (K = -2.21), and a prolonged survival (mean +/- SD) of 167 +/- 12 days compared to five recipients of > 3000/kg damaged islets (K = -0.814) (P = 0.0017) and a survival of 86 +/- 21 days (P = 0.0096). It is suggested that 31P-NMR spectroscopy is a valuable and practical method to predict islet graft viability prior to transplantation in order to assure good graft function in the recipient.

Animals↗
PubMed1994

Islet isolation and autotransplantation in pigs.

Despite recent considerable progress in the isolation and purification of porcine pancreatic islets the final proof of functional integrity has not yet been performed. In the present study the feasibility, technical problems and posttransplant metabolic function of islet transplantation in the pig were investigated. Intraductal collagenase perfusion technique for islet preparation was used in 27 landrace pigs and eight minipigs followed by intraportal or intrasplenic transplantation of the islets. Islet purification was performed by dextran gradient in six preparations. Islet quantification, portal vein pressure measurements, intra- and postoperative complications and postoperative graft function were monitored. Between 1.73 x 10(5) and 11.4 x 10(5) islet containing fragments (8.23 x 10(3)-54.28 x 10(3) islet containing fragments/kg recipient body weight) were transplanted. Portal vein thrombosis occurred in 4 animals with significantly elevated portal pressure (p = 0.0001). 11 of 27 landrace pigs died due to postoperative complications. None of the minipigs was lost due to perioperative mortality (p = 0.031). Four of eight landrace pigs with intrasplenic grafts (50%) were normoglycemic and two of eight landrace pigs with intrahepatic transplants (25%) were normoglycemic. In minipigs two out of four (50%) with intrasplenic transplants and two of four (50%) with intraportal transplants were normoglycemic. The results in glucose metabolism as measured with intravenous glucose tolerance tests and calculated by K-values were statistically significantly different between normoglycemic and hyperglycemic animals (landrace pigs p = 0.0002 and minipigs p = 0.0005). Longevity was prolonged in normoglycemic animals as compared to hyperglycemic and apancreatic animals. It is concluded that successful islet isolation and transplantation is feasible in the landrace pig and the minipig while the landrace pig appears to be more susceptable to perioperative mortality.

Animals↗
PubMed1991

[The pig--an experimental model for transplantation of isolated islets pancreatic islets].

The authors present results of autotransplantation of the islets of Langerhans of the pancreas in pigs and miniature pigs ("Troll"). Diabetes was induced by total pancreatomy. From the removed pancreas the islets of Langerhans were separated by the method of intraductal perfusion with collagenase and implanted into the spleen or liver via the portal vein. The mortality on operation in pigs was 33%, in miniature pigs 20%. In domestic pigs normal blood sugar levels were achieved in 25% after implantation of the islets of Langerhans into the liver (in 2 of 8 animals) and in 50% after implantation into the spleen (in 4 of 8 animals). In miniature pigs autotransplantation of the islets of Langerhans was equally successful when transplanted into the liver or the spleen -50%. The 50% success of autotransplantations justifies the use of pigs as a model for further investigations of allo- or xenotransplantations of the islets of Langerhans.

Animals↗
PubMed1991

[Extracorporeal lithotripsy--a new possibility in the treatment of gallstones?].

In the submitted review the author presents the results of treatment of cholelithiasis by extracorporeal lithotripsy by shock waves. Provided there is strict selection of patients with 1-3 cholesterol concrements in the gallbladder, treatment is successful in 70-90%. Complications occur in cca one third of the patients, the mortality rate is zero. The author gives criteria for indication which are met by cca 15-20% patients with cholelithiasis. In the discussion the author analyzes possibilities of urgent and preventive lithotripsy of gallstones, the number of relapses and biological effectiveness of shock sound waves, problems of competence and the economic effect of treatment.

Cholelithiasis↗
PubMed1990

[In vitro and in vivo studies of isolation, transplantation and function of Langerhans islets in the swine].

Limits and possibilities of the transplantation of islets of Langerhans in pigs were studied. 6 x 10(4) to 3 x 10(6) islets and insulin producing fragments per pancreas were obtained by intraductal collagenase digestion of the pancreatic gland following total pancreatectomy. Islets grafted into the spleen or liver rendered normoglycemia to the pancreatectomized animals as demonstrated by normal fasting blood sugars and normal intravenous glucose tolerance tests as compared to not operated animals permitting a survival time of up to one year. Apancreatic controls died of ketoacidosis and diabetic coma 10 to 12 days posttransplant. The number of isolated and transplanted islets correlated well to the normoglycemic state of the animal. Beyond that the in vitro challenge of the islets with glucose and resulting insulin secretion was a very important indicator for the functional status and integrity of the islets after transplantation. Thus the pig appears to be a suitable model for the preclinical studying of islet transplantation especially since immunologic, physiologic and anatomic features of the pig are similar to those in the human regarding pancreas and nutrition.

Animals↗
PubMed1990

[31P nuclear magnetic resonance spectroscopy of the stomach wall following proximal selective vagotomy].

The phosphate metabolism of the gastric wall after proximal selective vagotomy (PSV) was investigated by means of 31P-NMR spectroscopy. The destruction of metabolism has been found just after PSV resulting in a significant decrease of adenosine diphosphates and adenosine triphosphates. 4 and 7 days after PSV the progress of metabolism regeneration was detected, nevertheless with the retardation of high energy phosphates ischemic degradation. The results indicate not only a hydrochloric acid activity reduction but diminution of gastric mucosa protective factors, too. In experimental gastric ulcers no energy phosphates have been found suggesting a mucosa cells necrobiosis.

Animals↗