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R Ott

Publications and source records attributed to R Ott.

At least 19 recordsLinked to original sources
PubMed2001

Arterialization of the portal vein in liver transplantation: a new microsurgical model in the rat.

BACKGROUND: A preexisting thrombosis of the portal vein and the deep splanchnic bed can make it extremely difficult to reestablish the portal blood flow in orthotopic liver transplantation in man. Complete arterialization of the liver transplant, including the donor portal vein, might be a viable therapeutic option. A new rat transplantation model is described, in which the liver is completely arterialized. METHODS: The outflow of the portal blood in the recipient was secured via a portocaval shunt. Hepatectomy was then performed and the liver transplant placed in orthotopic position. An interposed aortic segment was used for direct arterialization of the donor portal vein. RESULTS: The laboratory parameters determined in the serum at the end of the observation period of 28 days revealed normal functioning of the transplant. The histological examinations showed largely normal cellular architecture, with no signs of necrosis, but incipient fibrosis. CONCLUSIONS: Using this new surgical technique in the rat liver transplantation model, long-term morphological and functional changes in a completely arterialized liver graft, and the regenerative capability of liver tissue perfused in this way, can be investigated.

Anastomosis, Surgical↗
PubMed2001

An allosteric synthetic catalyst: metal ions tune the activity of an artificial phosphodiesterase.

A trinuclear metal complex of general formula (L-H)M3(Mf)2 represents the first allosteric low molecular weight catalyst. L is a polyaza ligand having a tetradentate and two bidentate metal binding sites, Ms is a "structural" (allosteric) metal, and Mf are functional (catalytic) metals which interact with a substrate. In mononuclear [(L-H)Ms]+ complexes [(L-H)Cu(MeOH)]ClO4 (1a). [(L-H)Cu]NO3 x 2H2O (1b), [(L-H)Ni]ClO4 x 4H2O (2), and [(L-H)Pd]ClO4 x 2H2O (3), prepared from L and M2+ salts, the metal is strongly bound by an in-plane N4-coordination (confirmed by X-ray crystal structure determination of la). Formation of trinuclear complexes [(L-H)MsCu2]5+, with two functional Cu2+ ions coordinated to the bidentate sites of L, was evidenced in solution by photometric titration and by isolation of [(L-H)Cu3][PO4][ClO4]2 x 9H2O (4). The trinuclear complexes catalyze the cleavage of RNA-analogue 2-(hydroxypropyl)-p-nitrophenyl phosphate (HPNP), an activated phosphodiester. From a kinetic analysis of the cleavage rate at various HPNP concentrations, parameters KHPNP (the equilibrium constant for binding of HPNP to [(L-H)MsCu2]5+ and kcat (first-order rate constant for cleavage of HPNP when bound to the catalyst) were derived: KM= 170 (Ms= Cu2+), 340 (Ms = Ni2+), 2,600 (Ms = Pd2+) M(-1), kcat = 17 x 10(-3) (Ms= Cu2+) 3.1 x 10(-3) (Ms=Ni2+), 0.22 x 10(-3) (Ms = Pd2+) s(-1). Obviously, the nature of the allosteric metal ion Ms strongly influences both substrate affinity and reactivity of the catalyst [(L-H)MsCu2]5+. Our interpretation of this observation is that subtle differences in the ionic radius of Ms and in its tendency to distort the N4-Ms coordination plane have a significant influence on the conformation of the catalyst (i.e., preorganization of functional Cu2+ ions) and thus on catalytic activity.

Allosteric Regulation↗
PubMed2001

[Pseudoaneurysm of the hepatic artery--a rare complication after orthotopic liver transplantation].

INTRODUCTION: Pseudoaneurysm of the hepatic artery is a rare complication of liver transplantation, the most common cause of which--apart from technical surgical problems--is an infection. The most common symptoms are rupture and hemorrhage. METHOD: The present case report describes an asymptomatic pseudoaneurysm of the hepatic artery following liver transplantation, and its treatment. RESULTS: In this patient, an pseudoaneurysm involving an eroded branch of the hepatic artery was found. Surgical treatment consisted in the excision of the aneurysm and oversewing of the branch of the hepatic artery. CONCLUSION: The potential for rupture and hemorrhage makes surgical intervention mandatory even in asympotomatic patients with pseudoaneurysm of the hepatic artery. The surgical procedure depends on the local situation and the time elapsed since transplantation. Preservation or reconstruction of the arterial perfusion is essential.

Aneurysm, False↗
PubMed2001

[The anterior approach to hemihepatectomy].

When performing right hemihepatectomy, the anterior approach can be employed as an alternative to the conventional procedure in which, before dividing parenchymal tissue, the right lobe of the liver is completely mobilized, the vena cava exposed from the lateral aspect, and the veins entering it from the right half of the liver divided outside the organ. In particular, in the case of large or capsule-broaching tumors of the right liver lobe, exposure of the retrohepatic vena cava from the anterior aspect facilitates work on disection of the hepatic veins. Since with this approach the right lobe of the liver does not need to be removed out of its bed, perfusion of the remnant liver and the venous return via the vena cava remain unimpaired during the entire operation. Since manipulation of the tumor is minimal (no-touch technique), the risk of iatrogenic tumor perforation or hematogenous dissemination of malignant cells during surgery is reduced, and a surgical radical en bloc resection is facilitated. These technical and oncological benefits of the anterior approach must, however, be weighed against the increased risk of bleeding from hepatic veins during divisioning of the parenchyma, since, owing to the fact that the right lobe of the liver is not mobilised, such bleeding is frequently difficult to deal with.

Adult↗
PubMed2001

[Liver metastases--primary or multimodal therapy?].

Multimodal therapeutic concepts for the treatment of liver metastasis are currently undergoing evaluation--prompted by the fact that few patients have lasting benefit from resection alone. Thus, for example, in practice, virtually only metastases from colorectal carcinoma or neuroendocrine tumors can be referred to surgical treatment, and, of these, only 20-25% are technically resectable. Furthermore, even after an R0 resection, recurrent disease subsequently develops in 60-75% of the cases. In primarily non-resectable colorectal liver metastases, prior systemic treatment with 5-FU/folinic acid and oxaliplatin can result in partial or complete remission in 50-60% of cases and, depending on patient selection criteria, a secondary R0 resection rendered possible in 14-38%. Theoretical oncological considerations suggest that neoadjuvant treatment should be applied in the case of resectable liver metastases too. The question of whether the prognosis is then improved compared with resection alone is currently being investigated in a prospective multicentre study conducted by the EORTC. The value of adjuvant therapy administered with the aim of lowering the risk of recurrence following "curative" resection of liver metastases is presently not considered to have been adequately demonstrated. With regard to the efficacy of regional chemotherapy, the results of two prospective randomized studies are contradictory. Nor can the multimodal approach decisively improve the outcome of non-radical resection of metastatic lesions. This means that primary or secondary resection with a margin of clearance continues to represent the gold standard for the treatment of colorectal liver metastases. Neoadjuvant or adjuvant chemotherapy--where applicable with the additional use of various methods of thermal ablation (cryotherapy, laser therapy, high-frequency thermotherapy)--should be restricted to clinical trials.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Proprioception in somatoform disorders.

20 patients with somatoform disorders as defined by DSM-IV and 20 healthy controls were examined for their proprioception. Several psychophysiological theories of somatoform disorders suggest biased proprioceptive abilities. The primary question is, whether we may find an inaccurate myogen perception in somatization as suggested by the approach of Bischoff or a more precise proprioception as may be derived from concepts of a higher awareness of body reactions. Furthermore it is expected, that somatoform patients perceive their muscle tension more intensely than do healthy subjects. Proprioceptive abilities were tested using a visual EMG biofeedback task. Resulting objective data and subjective ratings were analyzed within a psychophysiological regression approach which allows one to estimate the reliability, precision and intensity of proprioception. Results revealed that somatoform subjects demonstrated a more precise but not a more intense perception of muscle tension than did healthy controls.

Adult↗
PubMed2001

Surgical treatment of HELLP syndrome-associated liver rupture -- an update.

In some 2% of the cases of the HELLP syndrome, severe spontaneous bleeding into the liver accompanied by haemorrhagic liver cell necrosis and rupture of the organ occurs and represents one of the main cause of death. On the basis of our own experience with four cases, a review of the literature is presented with particular focus on a therapeutic concept based on appropriate surgery. Within a MEDLINE search covering the period 1990-1999, the case reports of this kind of liver complication in the literature were analysed in terms of clinical course and outcome.In addition to our own four patients, a total of 49 cases with rupture of the liver were found in the literature. Despite surgical interventions, HELLP syndrome-associated liver rupture carried a mortality of 39%. Most patients died of haemorrhagic shock and organ failure. In order to improve survival, patients with ruptured liver or hepatic failure should be transferred to a centre with the necessary experience in liver surgery including liver transplantation. An interdisciplinary approach is required, including the use of temporary packing of the liver to control the bleeding, and during the further course of the condition, possibly even liver transplantation, as in one of our own cases.

Adult↗
PubMed2001

Impact of surgery on survival in palliative patients with metastatic colorectal cancer after first line treatment with weekly 24-hour infusion of high-dose 5-fluorouracil and folinic acid.

BACKGROUND: In palliative first-line treatment of colorectal cancer, the secondary resection of distant metastases after downstaging has constantly gained in importance. The objective of this prospective study was to examine the tumor response rate, the toxicity, the median survival time and the prognostic impact of metastatic resection after downstaging of consecutively enrolled patients with primary nonresectable colorectal cancer treated with once weekly 24-hour (24-h) infusion of high-dose 5-fluorouracil (5-FU) and folinic acid. PATIENTS AND METHODS: Between January 1995 and July 1997, 53 consecutive patients with primary nonresectable metastases were recruited for a prospective phase II study. The patients received in out-patient care 500 mg/m2 folinic acid in the form of a 1-2-hour infusion followed by 2600 mg/m2 5-FU administered as a 24-h infusion once weekly. One treatment cycle comprised six weekly infusions followed by a two week rest. Three cycles were administered, and in the event of complete remission (CR) or partial remission (PR) and good tolerability, a fourth cycle was undertaken. Thereafter, the possibility of performing a curative metastatic resection was investigated. RESULTS: Of the 53 patients treated, 7 showed a CR (13%), 15 patients a PR (28%), 26 patients stable disease (SD) (49%), and 5 patients progressive disease (PD) (10%). As the main symptom of toxicity, diarrhea (CTC grade 3 + 4) was observed in 11 patients (21%), followed by leucocytopenia (CTC grade 3 + 4) in 2 patients (4%), and the hand-foot syndrome in 1 patient (2%). The median survival time was 17 months with a median follow-up of 41 months (range: 28-59 months). In 9 patients (17%), a secondary metastatic resection was considered; in 6 patients (11%) curative resection was performed, and 4 patients (8%) showed no evidence of disease for at least three years. CONCLUSION: In this phase II study, we have been able to show prospectively that, after downstaging by palliative treatment using a weekly 24-h infusion of high-dose 5-FU and folinic acid, secondary curative metastatic resection was technically feasible in 11% of the patients. For some of these patients, long-term survival is therefore possible. Secondary metastatic resection should be carried out in close interdisciplinary cooperation, and should be further investigated in prospective phase III studies.

Aged↗
PubMed2001

A prospective electromyographic and computer-aided thermal sensitivity assessment of nerve lesions after sagittal split osteotomy and Le Fort I osteotomy.

PURPOSE: The purpose of this study was to determine the incidence of temporary and permanent sensory disturbance of the inferior alveolar nerve (IAN) after bilateral sagittal split osteotomy (BSSO) of the mandible and of the infraorbital nerve (ION) after Le Fort I osteotomy, as well as the rate of recovery of sensory function using subjective and objective measures. PATIENTS AND METHODS: Preoperatively and after 1 week, and 1, 3, 6, and 12 months postoperatively, sensibility in the distribution of 36 IONs after Le Fort I osteotomy and 24 IANs after BSSO in 19 patients were investigated by using sharp-blunt testing, 2-point discrimination, electromyographic recording, and thermal sensitivity (Pain and Thermal Sensitivity Test Device [PATH]) tests of the Adelta and C nerve fibers. RESULTS: With conventional clinical sharp-blunt and 2-point discrimination tests, the incidence of temporary impairment was 81% for the ION (29 of 36) and 83% for the IAN (20 of 24). The rate of permanent sensibility disturbance with conventional clinical testing was 6% for the ION and 15% for the IAN. Obvious recovery was found after 1 to 3 months for the ION, but it took 6 to 12 months for the IAN. In contrast, electromyography (EMG) testing showed lower rates of temporary sensory disturbance, namely, 54% (13 of 24) for the ION and 68% (15 of 22) for the IAN. Permanent sensory losses were not found. The results of the EMG test was confirmed by the PATH test. CONCLUSIONS: Objective tests for sensory disturbances show lower rates than the conventional tests. For quality control, preoperative and postoperative measurement and documentation of postoperative recovery of sensation is recommended.

Adolescent↗
PubMed2001

A new system for rapid large-caliber percutaneous transhepatic drainage in patients with obstructive jaundice: a prospective randomized trial.

UNLABELLED: BACKGROUND AND STUDY, AIMS: Percutaneous access to the biliary tract is an important diagnostic and therapeutic tool in the management of biliary diseases. It is usually chosen when the endoscopic approach via endoscopic retrograde cholangiopancreatography (ERCP) fails, or is not possible. Once established, the percutaneous tract is then used for the treatment of biliary stones and strictures. To establish a percutaneous tract with a caliber large enough for cholangioscopy to be performed, or for a large-bore permanent drainage tube to be inserted, stepwise dilation up to 14 Fr or 16 Fr is usually required. We present here a new method of rapid dilation using specially designed materials, including a stiffenable guide wire and specially adapted bougies. PATIENTS AND METHODS: Consecutive patients undergoing percutaneous drainage for biliary diseases were included in this prospective study, over a 19-month period. After establishment of a 10-Fr transpapillary drain, the patients were randomly assigned to either conventional percutaneous transhepatic biliary drainage (PTBD) or stepwise dilation using the new method, aiming at a need for only one further session, using a specially designed stiffenable metal guide wire of 6.6 Fr and plastic bougies. The details of the procedure (duration, materials used, technical ease), initial and later complications, assessment by the patients, and procedural costs were compared between the two groups. RESULTS: Of the 60 patients included, 29 were randomly assigned to group I (the new method) and 31 to group II (the conventional approach); there were no significant differences between the two groups in terms of clinical data or biliary pathology. The clinical efficacy of PTBD was similar in the two groups, although three patients in group II were switched to the new procedure because of failure of dilation using the conventional approach. The rates of major complications (four of 29 in group I, five of 31 in group II) and patient tolerance were also similar. However, the new procedure led to a significant reduction in the cumulative procedure duration (20.1 minutes vs 30.1 minutes), mean number of sessions (1.1 vs. 1.7), and mean number of hospital days (2.0 vs 5.5), and was therefore also cost-effective, reducing costs from a mean of 5813 to 2581 German marks (DM) per patient. CONCLUSIONS: The new system for rapid establishment of large-caliber PTBD offers significant advantages in terms of saving hospital resources while maintaining clinical efficacy.

Adult↗
PubMed2001

Treatment of achalasia: botulinum toxin injection vs. pneumatic balloon dilation. A prospective study with long-term follow-Up.

BACKGROUND AND STUDY AIMS: In patients with achalasia, intrasphincteric injection of botulinum toxin (BTX) has been suggested as an alternative regimen to balloon dilation and has been shown to be superior to placebo injection. The aim of the present study was to test the effectiveness, the long-term outcome and the cumulative costs of BTX injection in consecutive patients with symptomatic achalasia in comparison with pneumatic balloon dilation. PATIENTS AND METHODS: 37 patients, who presented with symptomatic achalasia between January 1994 and December 1996 were treated with either BTX injection (n = 23) or pneumatic dilation (n = 14). Patients with short-term or long-term symptomatic failures of the initial procedure were treated again, either with the same or with the alternative method, depending on the initial response and on the patient's wish. Symptoms were assessed using a global symptom score (0 - 10) which was evaluated before treatment and 1 week, 1 month and then every 6 months after the treatment. In addition, body weight and recurrence of symptoms were noted and manometry was carried out before and after treatment. The patients were regularly contacted for the long-term follow-up. RESULTS: There were significant improvements in the global symptom scores of all patients treated, in both the BTX injection group (before 8.2 +/- 1.3, after 3.0 +/- 1.6) and the dilation group (before 8.3 +/- 1.1, after 2.3 +/- 1.9). There was also a significant decrease of lower esophageal sphincter pressure after treatment in the BTX group and the dilation group. There were no significant differences with regard to overall treatment failure and long-term outcome between patients who had or had not received previous treatment. No major complications were encountered in either group. An actuarial analysis over 48 months comparing patients receiving BTX injection or balloon dilation demonstrated that after 12 months neither therapy was significantly superior. After 24 months a single pneumatic dilation was superior to a single BTX injection, and after 48 months all patients treated by BTX injection had experienced a symptomatic relapse. In contrast, 35 % of all patients treated by dilation and 45 % of patients treated successfully by dilation were still symptom-free in an intention-to-treat analysis after 48 months. When the overall costs of treatment and further treatment after recurrence were compared, dilation and BTX injection showed a similar cost-effectiveness (costs per symptom-free day) after 48 months. CONCLUSIONS: BTX injection, which can be performed in an outpatient setting, is as safe and cost-effective as balloon dilation in symptomatic achalasia. Taking into account the lower long-term efficacy of BTX injection therapy, however, it is an alternative only in a minority of older or high-risk patients.

Actuarial Analysis↗
PubMed2001

Autoantibody profile in progressive systemic sclerosis as markers for esophageal involvement.

We investigated the relationship between the severity and extent of esophageal involvement in patients with progressive systemic sclerosis (PSS) and the autoantibody profile. We studied 37 consecutive patients with PSS and compared their results to 25 healthy volunteers. Patients with PSS were separated into three subgroups: group 1 (antinuclear antibody [ANA] [+/-], anti-Sc170 antibody [Scl70] [-], and anticentromere antibody [ACA] [-]), group 2 (ANA [+], Scl70 [+], and ACA [-]), and group 3 (ANA [+], Scl70 [-], and ACA [+]). The lower esophageal sphincter pressure and the mean proximal esophageal amplitude were significantly lower in group 3 when compared with group 1, group 2, and the healthy controls. Distal esophageal aperistalsis was noted in 85% of group 3, 40% of group 2, and 30% of group 1. An involvement of esophageal motility was found in 100% of the patients with ACA. Our results suggest that esophageal involvement is more pronounced in patients with PSS with ACA as compared with patients with only Sc170 or ANA.

Adult↗
PubMed2001

Maximum bite force after the replacement of complete dentures.

OBJECTIVE: The aim of the present study was to investigate whether the maximum bite force (MBF) can be improved by the replacement of complete dentures for elderly people. DESIGN: Nine edentulous volunteers, mean age 74.2 (+/- 5.5) years and average denture experience 19.4 +/- 19.5 years (1 to 50 years) had replacement dentures made. After a rehearsal session, MBF was recorded with the old dentures, and with the new dentures immediately at insertion, at 3, 8 days, 2-3 weeks, 1, 2, 3 and 6-10 months post insertion (p-i.). MBF was recorded with the central bearing point method using a full-bridge strain gauge load cell. Data were analysed off-line using the mean of two peak readings per patient per session. RESULTS: The results indicate that MBF tended to be impaired when replacement dentures were first fitted (n.s.). However, this trend reversed during the first month p-i. for patients with a "moderate" lower ridge resorption of Atwood grade 3 or 4 (n = 5). Patients with more severe lower ridge resorption Atwood grade 5 or 6 (n = 4) showed a significantly lower MBF over the entire observation period (p < or = 0.05) and took longer to regain bite strength. Only patients with moderate bone resorption exceeded their pre-insertion level of MBF within the observation period of 6-10 months p-i. CONCLUSION: The present pilot study suggests that, at least for elderly patients with severe bone resorption, delayed improvement of MBF should be expected with replacement complete dentures.

Age Factors↗
PubMed2000

Activation of the DNA replication checkpoint through RNA synthesis by primase.

When DNA replication is inhibited during the synthesis (S) phase of the cell cycle, a signaling pathway (checkpoint) is activated that serves to prevent mitosis from initiating before completion of replication. This replication checkpoint acts by down-regulating the activity of the mitotic inducer cdc2-cyclin B. Here, we report the relation between chromatin structure and induction of the replication checkpoint. Chromatin was competent to initiate a checkpoint response only after the DNA was unwound and DNA polymerase alpha had been loaded. Checkpoint induction did not require new DNA synthesis on the unwound template strand but did require RNA primer synthesis by primase. These findings identify the RNA portion of the primer as an important component of the signal that activates the replication checkpoint.

Animals↗
PubMed2000

[Undifferentiated, embryonal sarcoma as a rare cause of spontaneous liver rupture in adults].

INTRODUCTION: Undifferentiated, embryonal sarcoma is a rare malignant tumour of the liver, the incidence of which is highest in children between 6 and 10 years of age (14.1 %). Among the primary tumours of the liver in childhood it ranks in third place after hepatocellular carcinoma and focal nodular hyperplasia. Embryonal sarcoma is much rarer in adults. To our knowledge, only 18 cases have been published in the last 50 years. METHODS AND RESULTS: We now present the case of a 29-year-old woman with spontaneous rupture of the liver caused by an undifferentiated sarcoma. CONCLUSION: This case report illustrates the possibility of an embryonal sarcoma being the reason for spontaneous rupture of the liver. The management of this case comprised primary tamponade, interventional embolisation of the feeding artery, and secondary resection under stable conditions.

Adult↗
PubMed2000

[Illness-related stress in psoriasis vulgaris. Validation of the "Psoriasis Daily Stress Inventory"].

BACKGROUND AND OBJECTIVE: Illness specific stress plays an important part in the daily life of psoriatic patients. Until now for the measurement of relevant aspects of daily stress only the "Psoriasis Life Stress Inventory" (PLSI) of Gupta & Gupta exists; with the "Psoriasis-Alltagsstress-Inventar" (PAI), a German version of the PLSI is presented and its psychometric properties are discussed. PATIENTS/METHODS: 385 in-patients completed the PAI. The internal validity was examined by factor analysis. Moreover, the correlations between the PAI total score and sociodemographic parameters (ANOVA) and extent of skin involvement (multiple regression) were determined. RESULTS: The PLSI score proves to be sufficiently independent of age, sex, age at onset, and general extent of skin involvement. However, affections of the hands, the lower abdomen and the genitals show a strong influence on the total score. We found marked interrelations with the stigmatization feeling ("Questionnaire on Experience with Skin Complaints" QES, Schmid-Ott et al. 1998). CONCLUSIONS: The results suggest that the PAI is a useful and psychologically relevant questionnaire for psoriatic patients.

Adult↗