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Biomedical subjects

J Rösch

Publications and source records attributed to J Rösch.

At least 19 recordsLinked to original sources
PubMed1998

Percutaneous retroperitoneal splenorenal shunt: an experimental study in swine.

PURPOSE: To evaluate the technical possibility of creating a percutaneous retroperitoneal splenorenal shunt (PRESS) in swine as a minimally invasive treatment of portal hypertension. MATERIALS AND METHODS: Five normal domestic swine underwent creation of a PRESS. A modified transjugular intrahepatic portosystemic shunt puncture set was introduced from the right femoral vein into the left renal vein. The proximal splenic vein was punctured transvenously through the retroperitoneal cavity. Noncovered metallic stents were then placed to connect both veins. The animals were sacrificed 1 hour after the procedure, after follow-up splenic venography and necropsy were performed. RESULTS: Puncture of the splenic vein and stent placement were successfully completed in all cases. In four of five cases, the splenic venogram revealed good flow from the splenic vein to the left renal vein through the shunt track 1 hour after creation of the PRESS, and there was no evidence of leakage. No changes in vital signs were noticed. At necropsy, a small retroperitoneal hematoma along the stent and minimal intraperitoneal bleeding were observed. The stents were found in the retroperitoneal cavity connecting both veins in all animals. CONCLUSION: Creation of a PRESS is technically possible, and further experimental studies of its efficacy are warranted.

Animals↗
PubMed1997

Reactivity-based coronary vasospasm independent of atherosclerosis in rhesus monkeys.

OBJECTIVES: We studied the hypothesis that in the absence of vascular pathology, coronary artery vasospasm occurs as a result of local regions of vascular muscle hyperreactivity. We aimed to explore the basis for a functional etiology of those vasospasms not explained on a structural basis. BACKGROUND: Ovariectomized rhesus monkeys (Macaca mulatta) without injury or significant vascular disease were stimulated with platelet release products, and angiograms were compared with those from vasospasms induced in human patients. METHODS: We used intracoronary (IC) injections of serotonin, thromboxane A2 (U46619), endothelin 1 or angiotensin II in concentrations 3 to 10 times that which reduced coronary artery diameter by 50%. RESULTS: Although no agent alone caused vasospasm, the combination of pathophysiologic concentrations of serotonin and the stable thromboxane A2 mimetic, U46619, injected through an IC catheter, synergistically caused coronary vasospasm on the second or third challenge in five of seven monkeys. These drug-induced vasospasms were similar to vasospasms induced by mechanical injury followed by serotonin, and to those stimulated in human IC diagnostic tests, as judged by onset, appearance, kinetics and vasodilator reversal. CONCLUSIONS: These studies in ovariectomized monkeys revealed that coronary vasospasm can be stimulated without preexisting vascular pathology, endothelial denudation or injury. Reproducible vasospasm of primate coronary arteries in response to these two endogenous pathophysiologic vasoconstrictors, which are thought to be precipitating stimuli in the etiology of vasospasm, suggests that structure-independent epicardial vasospasm can be an important element in serious cardiac ischemic events, particularly the focal, persistent vasospasms that occur without plaques or injury.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

Medroxyprogesterone interferes with ovarian steroid protection against coronary vasospasm.

Cardiovascular disease, the major cause of death in post-menopausal women, can be reduced by replacement of ovarian steroid hormones. To compare medroxyprogesterone with progesterone as the progestin in hormone replacement therapy from the standpoint of coronary artery vasospasm, we treated ovariectomized rhesus monkeys with physiological levels of estradiol-17 beta in combination with medroxyprogesterone or progesterone for four weeks. Coronary vasospasm in response to pathophysiological stimulation without injury showed that progesterone plus estradiol protected but medroxyprogesterone plus estradiol failed to protect, allowing vasospasm. We conclude that medroxyprogesterone in contrast to progesterone increases the risk of coronary vasospasm.

Animals↗
PubMed1996

Treatment of esophageal obstruction from mediastinal compressive tumor with covered, self-expanding metallic Z-stents.

BACKGROUND: Mediastinal malignancies may involve the esophagus, leading to esophageal stenosis and dysphagia. Rigid and self-expanding esophageal stents have been used for effective palliation, but their use in extrinsic, compressive lesions is controversial. METHODS: A retrospective review of self-expanding Gianturco-Rösch Z-stents that were successfully placed in 13 patients with malignant esophageal obstruction due to extrinsic lesions. RESULTS: All patients had an improvement in dysphagia of at least two dysphagia grades. The mean dysphagia grade fell from 3.15 to 0.62. Mean survival was 2.2 months. Early (within 48 hours) procedure-related complications occurred in 4 of 13 patients and consisted of minor, transient chest pain that resolved within 6 hours (3 patients) and endoscopic stent dislodgment into the stomach (1 patient). Late complications (> 48 hours) occurred in 2 patients and consisted of a partial proximal stent migration and the development of a benign stricture proximal to the stent. There was no procedural or stent related mortality. CONCLUSIONS: Esophageal obstruction and malignant dysphagia from extrinsic, compressive mediastinal malignancies can be effectively and safely palliated with self-expanding Gianturco- Rösch Z-stents.

Aged↗
PubMed1995

Transfemoral intraluminal stent graft implanted for thoracic aortic aneurysm.

We describe two patients with inoperable descending thoracic aortic aneurysm. The first patient had complained of severe back pain for at least thirteen years. Radiological examination revealed a large posterior mediastinal mass that was misdiagnosed in 1981. Follow-up studies in 1992 revealed this mass to be a large descending thoracic aortic aneurysm, eroding the vertebral bodies of T3 through T6 and entering the spinal canal. Because of the high risk, thoracic aortic surgery was not performed. The second patient had an acute descending thoracic aortic aneurysm. There was contraindication to a second surgical approach due to previous thoracotomy. Both patients underwent an intraluminal bypass of the descending thoracic aorta with a stent graft. Postplacement aortogram and follow-up studies showed that aneurysm was effectively excluded. We believe that this type of therapy should be offered to selected individuals who are considered by cardiovascular surgeons to be a high risk for thoracic aneurysm surgery.

Acute Disease↗
PubMed1995

Improved transjugular intrahepatic portosystemic shunt patency with PTFE-covered stent-grafts: experimental results in swine.

PURPOSE: To evaluate the ability of stent-grafts made with polytetrafluoroethylene (PTFE) graft material to improve transjugular intrahepatic portosystemic shunt (TIPS) patency. MATERIALS AND METHODS: TIPS were created in 13 swine by using PTFE-covered stent-grafts. Uncovered TIPS were placed in 13 other swine. Twenty-one of 26 animals were followed up with portal venography for 3 months or until the shunt became severely stenotic. Five animals without severe stenosis were sacrificed before 3 months because of illness. RESULTS: At 4 weeks after TIPS placement, nine of 13 stent-graft TIPS were patent (< 50% diameter narrowing) compared with only one patent stent in 13 uncovered TIPS. Six of 13 stent-graft TIPS remained patent until the animals were sacrificed. In 11 of 12 uncovered TIPS, stenosis was most prominent in the parenchymal tract. In five of seven stent-graft TIPS, stenosis was most prominent in the hepatic vein above the end of the graft material. Bile leaks were discovered in six occluded uncovered TIPS and in two of the stent-graft TIPS. CONCLUSION: PTFE-covered stent-grafts significantly improved TIPS patency in swine (P < .01). However, stenosis in the hepatic vein led to late shunt malfunction in selected cases.

Animals↗
PubMed1993

Self-expandable spindle for transcatheter vascular occlusion: in vivo experiments. Work in progress.

A mechanical vascular occluder was studied in eight pigs to test its efficacy in arteries of different diameters, stability over time, and safety in placement. The main component is a self-expandable spindle made of tubular stainless steel mesh. Simple steel spindles, double spindles, and Dacron-core spindles were placed in the common carotid artery, main renal artery, renal artery branches, and infrarenal aorta. Follow-up arteriograms were obtained immediately, 30-60 minutes, and (except for aortic spindles) 7 days after deployment. The left common carotid artery was occluded in all pigs, regardless of spindle type. In the main renal artery and its branches, simple steel spindles did not achieve complete occlusion. Double and Dacron-core spindles produced immediate occlusion without recanalization on the 1-week follow-up arteriogram, except for one spindle with an incomplete Dacron core and two spindles that did not completely fill the arterial lumen. Two Dacron-core spindles achieved immediate complete occlusion of the infrarenal aorta. No migration was seen with any spindle.

Animals↗
PubMed1992

Transjugular liver biopsy.

Although transjugular liver biopsy requires the availability of trained personnel, takes more time than percutaneous biopsy and is moderately expensive, it is a safe alternative technique for obtaining adequate liver tissue for diagnosis in special clinical situations. The usual indications for transjugular rather than percutaneous liver biopsy are (a) coagulation disorder (prothrombin time greater than 3 sec over control value and/or platelet count less than 60,000/cm3), (b) massive ascites and (c) desire to perform ancillary procedures, such as measurement of pressures or opacification of the hepatic veins and inferior vena cava. Less common indications for transjugular liver biopsy include failed percutaneous biopsy, massive obesity, small cirrhotic liver (increased risk and lower success rate) and suspected vascular tumor or peliosis hepatis. Results from several centers indicate that adequate or diagnostic liver tissue is obtained in 81% to 97% of cases. The typical length of the biopsy core ranges from 0.3 cm to 2.0 cm. Modification of the classic technique, particularly the adaptation of a Tru-Cut needle, shows promise in yielding longer cores of tissue with less fragmentation. Transjugular liver biopsy is performed with an acceptable complication rate that ranges 0% to 20%. The reported mortality of transjugular liver biopsy was 0 in three major centers and ranged from 0.1% to 0.5% in three other centers. Transjugular liver biopsy may be useful in obtaining diagnostic liver tissue not only in advanced chronic liver disease with coagulopathy, ascites or both, but also in patients with fulminant hepatic failure to better determine prognosis and the need for liver transplantation.

Adolescent↗
PubMed1992

In vitro comparison of the spiral Z stent and the Gianturco Z stent.

A new spiral Z stent is described, and its characteristics are compared in vitro with those of the modified Gianturco Z stent. The spiral Z stent has a more uniform expansile force throughout its effective length; is more compressible, thus allowing for use of a smaller introductory catheter; and is more stable than the modified Z stent. Flexibility of both stent types is similar. Advantages of the spiral Z stent promise to be beneficial for clinical use.

Equipment Design↗
PubMed1992

Silicone-covered expandable metallic stents in the esophagus: an experimental study.

Modified silicone-covered Gianturco expandable metallic stents were placed in the normal esophagus of six young pigs. Following endoscopic examination, the stents were placed using endoscopic and fluoroscopic control. The animals were observed for eating behavior and weight gain. Stents appeared to be tolerated well based on these parameters. Three stents remained in position for the full study period, and three stents migrated into the stomach during the study. The pigs were sacrificed at four weeks and postmortem examination performed. Esophageal wall thickening and nodular inflammation were noted at the sites where the wire skirts penetrated the mucosa. Injury was limited to the region of the wire skirts and there was no injury due to the radial force of the stent body. There was no free perforation. This preliminary study suggests that endoscopic and fluoroscopic placement of modified silicone-covered Gianturco stents in the esophagus is feasible and safe. More extensive animal studies, followed by clinical investigation for palliation of malignant strictures, are warranted.

Animals↗
PubMed1991

Radiographic fallopian tube recanalization: absorbed ovarian radiation dose.

Absorbed radiation dose to the ovaries during radiographic fallopian tube recanalization was estimated in 29 patients with use of thermoluminescent dosimeters placed in the vaginal fornix. With an average fluoroscopic time of 8.5 minutes +/- 5.5 and an average of 14 +/- 5 105-mm spot radiographs obtained, the average absorbed dose to the ovaries was 8.5 mGy +/- 5.6 (0.85 rad +/- 0.56). Technical guidelines for keeping patient radiation exposure to a minimum during this new interventional procedure are suggested.

Adult↗
PubMed1991

Expandable venous stents for treatment of the Budd-Chiari syndrome.

The goals of treatment of the Budd-Chiari syndrome are relief of portal hypertension, relief of inferior vena cava syndrome, if present, and preservation of hepatic function. This study presents a patient with clinical resolution of the Budd-Chiari syndrome after placement of expandable metallic stents in the inferior vena cava and hepatic veins. A 26-year-old man with severe ascites and lower extremity edema but with relatively preserved hepatic function had a small gradient across a suprahepatic caval web, large gradients across an intrahepatic caval stenosis and the left hepatic vein, and an occluded right hepatic vein. Under angiographic control, web and caval stenosis were balloon-dilated, and modified Gianturco expandable metallic stents were placed in the intrahepatic vena cava. The left hepatic vein was dilated twice and a stent was placed. All gradients were completely eliminated. There were no complications and after 1 year, the stents have fully expanded without migration, edema and ascites have resolved, hepatic function has normalized, and the patient has returned to work. This new technique provides a simple, safe, effective, relatively inexpensive, and potentially long-lasting treatment for selected patients with the Budd-Chiari syndrome.

Adult↗
PubMed1990

Phosphorylation and thiophosphorylation by myosin light chain kinase: different effects on mechanical properties of chemically skinned ventricular fibers from the pig.

The influence of myosin light chain phosphorylation (treatment with myosin light chain kinase = MLCK, calmodulin and ATP) and thiophosphorylation (incubation with MLCK, calmodulin and ATP gamma S) on the maximal shortening velocity (Vmax) and Ca2+ sensitivity of chemically-skinned ventricular fibers from the pig has been studied. Vmax was determined by the slack-test method and by extrapolation of the force-velocity relation by the isotonic quick release method. Vmax was 1.53 muscle length/s (L/s) and 1.94 L/s using the force-velocity relation and the slack-test, respectively. Phosphorylation increased the Ca2+ sensitivity for isometric force development of skinned fibers but had no influence on Vmax. Thiophosphorylation decreased Vmax but had no influence on Ca2+ sensitivity. Phosphorylation pattern of the myosin light chains of the skinned fibers was studied using [gamma-32P]ATP or [gamma-P35S]ATP (250 muCi each) and autoradiography. Incubation of skinned fibers with labeled ATP led to a phosphate incorporation into the 18-kDa myosin light chain (MPLC or regulatory light chain) while incubation with labeled ATP gamma S led to an incorporation of thiophosphate into the 28-kDa myosin light chain (alkali light chain) and tropomyosin. We suggest that the difference in mechanical behavior between phosphorylated and thiophosphorylated skinned fibers are due to differences in the phosphorylation profiles of myofibrillar regulatory proteins.

Adenosine Triphosphate↗
PubMed1990

Nonsurgical fallopian tube recanalization for treatment of infertility.

Fluoroscopic transcervical fallopian tube recanalization was performed in 100 consecutive patients with infertility and proximal tubal obstruction documented with hysterosalpingography. In 86 patients, the procedure enabled at least one tube to be opened. Twenty-six intrauterine pregnancies resulted from the successful recanalization. A well-defined subset of 20 patients were evaluated to better define the treatment effect of fallopian tube recanalization. All 20 had bilateral proximal tubal obstruction without other tubal disease, and all had been recommended for tubal microsurgery or in vitro fertilization. Recanalization of one or both tubes was successful in 19 of these women (95%). Nine patients conceived (47%) without receiving any other therapy, and the average time from procedure to conception was 4 months. All pregnancies were intrauterine. Eight of the 10 patients who did not conceive underwent follow-up hysterosalpingography an average of 6 months following the procedure; four (50%) demonstrated reocclusion of both tubes. The authors conclude that nonsurgical fallopian tube recanalization is an effective treatment for infertility caused by proximal tubal obstruction.

Adult↗
PubMed1990

Device for hysterosalpingography and fallopian tube catheterization.

A device was developed for hysterosalpingography and fallopian tube recanalization. It differs from the previously used vacuum-cup device in that the central shaft slides and has an acorn-shaped tip. Optimal results were obtained in all 14 women (100%) who underwent catheterization with the new device; optimal results were achieved in only five of eight women (62%) who underwent catheterization with the fixed-shaft device during the same time period.

Catheterization↗