Biomedical subjects

R Ott

Publications and source records attributed to R Ott.

At least 19 recordsLinked to original sources

PubMed2006

Biocompatibility of bacterial contaminated prosthetic meshes and porcine dermal collagen used to repair abdominal wall defects.

BACKGROUND AND AIMS: A contaminated or infected surgical site is considered a contraindication for the use of the nonabsorbable alloplastic materials employed to repair abdominal wall defects. Therefore, the biocompatibility of new prosthetic materials was investigated. MATERIALS AND METHODS: Meshes measuring 1.5x1.5 cm made of conventional and titanium-coated polypropylene, polyglycol, or porcine dermal collagen were implanted under the abdominal wall of 96 rats (eight groups of 12 animals each) employing the inlay technique. Implantation of all four materials was performed both under semisterile conditions and bacterial contamination of the mesh. The meshes were explanted after 28 days. RESULTS: All the materials implanted under semisterile conditions were incorporated into the abdominal wall with only few intraabdominal adhesions (mean adhesion scores: 1.0, 1.2, 1.0, 0.8 points, respectively, not significant). With the porcine dermal collagen, proliferation rate and the proportion of inflammatory cells were statistically lower (p<0.01). In the bacterial contamination group, all meshes were associated with a suppurating infection and strong adhesions between the bowel and mesh, which were most prominent in the case of dermal collagen (mean adhesion scores: 1.6, 1.7, 1.7, and 1.9 points, respectively, not significant). In this group, two animals died of peritonitis. In comparison with the other materials, the proliferation rate was significantly elevated (p=0.03). No significant differences were seen between the other materials employed. CONCLUSION: Irrespective of the material employed, implantation of alloplastic meshes in an abdominal wall contaminated with bacteria, is associated with suppurating infections, in particular in the case of the membrane-like porcine dermal collagen. Nonabsorbable alloplastic meshes and dermal skin grafts should therefore not be used to repair infected abdominal wall defects.

Abdominal Wall↗

PubMed2006

[Indigenous helminthiasis].

Worldwide an estimated 1.5-2 billion people are infested with helminths. Over the last decades, in industrialized countries prevalence rates of human helminthic infections were decreased by means of wastewater and food control. In this article, we review the geographic distributions as well as the impact on the public health system of the most prevalent helminthiases. Special emphasis is given to Echinococcus, Enterobiasis, and Toxocariasis. Intestinal larvae or eggs of helminths can be detected in faeces. Pinworms are collected with a strip of cellophane tape with the sticky side towards the anus. Tissue helminthosis, like Toxocariasis or Trichinosis are associated with eosinophilia and can be diagnosed with sensitive immunological methods or by biopsy. Infection with Echinococcus multilocularis is the most serious parasitic disease in central Europe. Although current therapeutic options are limited, 5 year survival rates were markedly improved by the combination of medical and surgical treatment.

Demography↗

PubMed2006

[Tropical and subtropical helminthoses].

Human helminthic infestations are extraordinarily common in tropical regions and represent a significant burden for those countries and their populations. The risk of intestinal helminthoses is further increased by poverty. Particularly in children helminthoses lead to malnutrition (ascariasis etc) or iron and protein deficiency (ancylostomiasis). Tropical helminthoses like schistosomiasis and filariasis can cause severe organ damage, starvation, and early death. In contrast, returning travellers very rarely acquire tropical helminthoses, if they follow simple hygienic rules. Furthermore, the worm burden in returning travelers hardly ever is high enough to cause severe illness. Therefore, tropical helminthosis is more common in immigrants from endemic areas compared to returning travelers.

Demography↗

PubMed2006

[Need and extension of lymph node dissection in gallbladder carcinoma].

Gallbladder carcinomas have the propensity to metastasize early, commonly into locoregional lymph nodes. For gallbladder carcinomas with infiltration of at least the muscularis (pT1b) or subserosa (pT2), surgical therapy with a curative intent always includes a locoregional lymphadenectomy besides cholecystectomy and an anatomical or atypical liver resection. In incidentally discovered gallbladder carcinomas, such a locoregional lymphadenectomy should be performed depending on the age of the patient and on tumor extension. However, this only is helpful with respect to prognosis, if the metastases are limited to the hepatoduodenal ligament or to the posterosuperior pancreaticoduodenal nodes. For gallbladder carcinomas with metastases into more distal lymph nodes, especially in paraaortal nodes, lymphadenectomy only rarely impacts long-term survival. An extended lymphadenectomy that includes resection of the bile duct and/or pancreatic head is associated with an increased rate of morbidity and mortality, therefore not being of proven advantage in terms of prognosis.

Cholecystectomy↗

PubMed2005

[Tracheobronchial ruptures: classification and management].

BACKGROUND: Tracheobronchial ruptures are rare surgical emergencies with significant mortality. We present management and outcome of such ruptures treated at the University of Leipzig in Germany and propose a novel therapeutic algorithm-a new classification system for stratifying treatment of patients with tracheobronchial ruptures. METHODS: We retrospectively studied 24 patients 19 to 88 years old who were treated in our institution for tracheobronchial injury. RESULTS: Eighty-seven percent of the injuries were caused iatrogenically. Fifty-four percent were type I injuries (isolated tracheal lesions), 38% type II (involvement of carina or main stem bronchi), and 8% type III (distal lesions of lobar or segmental bronchi). Seventy-five percent of the patients were operated via right-sided dorsolateral thoracotomy. In four (22%), insufficiency of the tracheal closure occurred, with mediastinitis possibly being a significant risk factor for this event (P<0.001). In surgically treated patients, rupture-related and overall mortality were 5.5% and 28%, respectively, whereas in medically treated patients, mortality was 33%. CONCLUSION: The proposed classification of tracheobronchial injuries enables stratifying the treatment of patients with tracheobronchial ruptures. Type I lesions can be surgically closed either by a right-sided thoracotomy or transcervical-transtracheal approach. In contrast, surgical management of type II and III injuries always requires thoracotomy.

Adult↗

PubMed2005

[Surgical management, prognostic factors, and outcome in hepatic trauma].

Hepatic trauma is a rare surgical emergency with significant morbidity and mortality. Extensive experience in liver surgery is a prerequisite for the management of these injuries. The medical records of 68 consecutive patients with hepatic trauma were retrospectively reviewed for the severity of liver injury, management, morbidity, mortality, and risk factors. Of the patients, 14 were treated conservatively and 52 surgically (24 suture/fibrin glue, 16 perihepatic packing, 11 resections, 1 liver transplantation). Two patients died just before emergency surgery could be performed. Overall mortality was 21% (14/68), and 13, 14, 6, 27, and 50% for types I, II, III, IV, and V injuries, respectively. Only nine deaths (all type IV and V) were liver related, while four were caused by extrahepatic injuries and one by concomitant liver cirrhosis. With respect to treatment, conservative management, suture, and resection had a low mortality of 0, 4, and 9%, respectively. In contrast, mortality was 47% in patients in whom only packing was performed (in severe injuries). Stepwise multivariate regression analysis proved prothrombin values <40%, ISS scores >30, and transfusion requirements of more than 10 red packed cells to be significant risk factors for post-traumatic death. Type I-III hepatic injuries can safely be treated by conservative or simple surgical means. However, complex hepatic injuries (types IV and V) carry a significant mortality and may require hepatic surgery, including liver resection or even transplantation. Therefore, patients with severe hepatic injuries should be treated in a specialized institution.

Adolescent↗

PubMed2004

[Idiopathic hypereosinophilia with cardiac involvement].

HISTORY AND CLINICAL FINDINGS: A 34-year-old previously healthy woman was admitted to another hospital because of abdominal pain, cough and dyspnea. Peripheral eosinophilia was present. Two months later she was admitted to the cardiology department with signs of mitral regurgitation. Dyspnea, fatigue, skin rashes with pruritus and a systolic murmur were noted. INVESTIGATIONS: Laboratory tests showed 11.4/nl leukocytes (normal range 4.8-10.8/nl) with an eosinophilia of 19% (normal range < 4%) corresponding to 2.2/nl. Cardiac magnetic resonance imaging revealed endomyocardial fibrosis involving the posterior mitral leaflet with resulting valvular regurgitation. Doppler ultrasound showed restrictive heart failure. DIAGNOSIS, THERAPY AND FURTHER COURSE: The diagnosis of idiopathic hypereosinophilia most likely as part of hypereosinophilic syndrome with cardiac involvement was made. The patient was treated with digitalis, diuretics and peptidyl dipeptidase (PDP) inhibitor. The treatment with glucocorticoids and cytotoxic agent to achieve a reduction of eosinophil count was ended by the patient a few weeks later. CONCLUSION: The hypereosinophilic syndrome with endomyocardial fibrosis is rare, and its prognosis is grave. The pathophysiological mechanisms are not entirely clear, nearly 70 years after Löffler first described fibrous endocarditis with eosinophilia. Patients receive symptomatic medical therapies. Additional surgical treatment has been reported,. Antihypereosinophilic therapy is used to control the disease.

Adult↗

PubMed2004

The Munich Barrett follow up study: suspicion of Barrett's oesophagus based on either endoscopy or histology only--what is the clinical significance?

BACKGROUND: The incidence of distal oesophageal adenocarcinoma is rising, with chronic reflux and Barrett's oesophagus being considered risk factors. Reliable detection of Barrett's oesophagus during upper endoscopy is therefore mandatory but requires both endoscopy and histology for confirmation. Appropriate management of patients with endoscopic suspicion but negative on histology, or vice versa, or of patients with no endoscopic suspicion but with a biopsy diagnosis of intestinal metaplasia at the gastro-oesophageal junction, has not yet been studied prospectively. PATIENTS AND METHODS: In a prospective multicentre study, 929 patients (51% male, mean age 50 years) referred for upper gastrointestinal endoscopy were included; 59% had reflux symptoms. The endoscopic aspect of the Z line and any suspicion of Barrett's oesophagus were noted, and biopsies were taken in all patients from the Z line (n = 4), gastric cardia (n = 2), and body and antrum (n = 2 each). Biopsies positive for specialised intestinal metaplasia (SIM) were reviewed by a reference pathologist for a final Barrett's oesophagus diagnosis. All patients with endoscopic and/or histological suspicion of Barrett's oesophagus were invited for a follow up endoscopy; the remaining cases (no endoscopic or histological suspicion of Barrett's oesophagus) were followed clinically. RESULTS: Of 235 patients positive for Barrett's oesophagus on endoscopy and/or histology, 63% agreed to undergo repeat endoscopy (mean follow up period 30.5 months). 46% of patients with an endoscopic Barrett's oesophagus diagnosis but no histological confirmation (group A) showed the same distribution, a further 42% did not have Barrett's oesophagus, and 11% had confirmed Barrett's oesophagus on both endoscopy and biopsy on follow up. In the group with a histological Barrett's oesophagus diagnosis but negative on initial endoscopy (group B), follow up showed the same in 26% whereas 46% had no Barrett's oesophagus, and confirmed Barrett's oesophagus (endoscopy plus histology) was diagnosed in 17%. Of the study population, 16 patients had Barrett's oesophagus on initial endoscopy confirmed by histology which remained constant in 70% at follow up (group C). Of the remaining patients without an initial Barrett's oesophagus diagnosis on either endoscopy or histology (group D) and only clinical follow up (mean follow up period 38 months), one confirmed Barrett's oesophagus case was found among 100 patients re-endoscoped outside of the study protocol. However, no single case of dysplasia or cancer of the distal oesophagus was detected in any patient during the study period. CONCLUSIONS: Even in a specialised gastroenterology setting, reproducibility of presumptive endoscopic or histological diagnoses of Barrett's oesophagus at follow up were poor. Only 10-20% of cases with either endoscopic or histological suspicion of Barrett's oesophagus had established Barrett's oesophagus after 2.5 years of follow up. The risk of dysplasia in this population was very low and hence meticulous follow up may not be required.

Adolescent↗

PubMed2003

In yeast sterol biosynthesis the 3-keto reductase protein (Erg27p) is required for oxidosqualene cyclase (Erg7p) activity.

In Saccharomyces cerevisiae, the 3-keto reductase (Erg27p) encoded by ERG27 gene is one of the key enzymes involved in the C-4 demethylation of the sterol intermediate, 4,4-dimethylzymosterol. The oxidosqualene cyclase (Erg7p) encoded by the ERG7 gene converts oxidosqualene to lanosterol, the first cyclic component of sterol biosynthesis. In a previous study, we found that erg27 strains grown on cholesterol- or ergosterol-supplemented media did not accumulate lanosterol or 3-ketosterols but rather squalene, oxidosqualene, and dioxidosqualene intermediates normally observed in ERG7 (oxidosqualene cyclase) mutants. These results suggested a possible interaction between these two enzymes. In this study, we present evidence that Erg27p interacts with Erg7p, facilitating the association of Erg7p with lipid particles (LPs) and preventing digestion of Erg7p both in the endoplasmic reticulum (ER) and LPs. We demonstrate that Erg27p is required for oxidosqualene cyclase (Erg7p) activity in LPs, and that Erg27p co-immunoprecipitates with Erg7p in LPs but not in microsomal fractions. While Erg27p is essentially a component of the ER, it can also be detected in LPs. In erg27 strains, a truncated Erg7p mislocalizes to microsomes. Restoration of Erg7p enzyme activity and LPs localization was achieved in an erg27 strain transformed with a plasmid containing a wild-type ERG27 allele. We suggest that the physical interaction of Erg27p with Erg7p is an essential regulatory tool in yeast sterol biosynthesis.

Alleles↗

PubMed2003

Incisional hernia repair after orthotopic liver transplantation: a technique employing an inlay/onlay polypropylene mesh.

BACKGROUND: The literature provides no data on the incidence and operative management of incisional hernias developing after orthotopic liver transplantation. The use of high-dose immunosuppressive agents results in an appreciable delay in wound healing. There is thus a need for a procedure for the reconstruction of the abdominal wall for patients on immunosuppression. The aim of this retrospective study was to establish the incidence of incisional hernias and an analysis of the results after implantation of a polypropylene mesh in inlay-onlay technique after liver transplantation is given. METHODS: The basis for the present retrospective investigations was a total of 207 liver transplantations carried out in 192 patients (15 re-transplantations). After performing tensiometry, a polypropylene mesh (Marlex) was implanted to close the hernias using the inlay/onlay technique or a direct closure of the fascia was done. All treated hernias were followed up for a median of 18 months. RESULTS: Among 184 patients, 17 developed incisional hernias after primary direct closure of the abdominal wall, giving an incidence of 9%. In an additional 8 patients an incisional hernia was seen where an absorbable mesh was used to close the abdominal wall after liver transplantation. In addition, there were 25 incisional hernias after 207 liver transplantations (12%). One of 15 (7%) of the surgically repaired hernias with implantation of a polypropylene mesh (Marlex) developed a recurrence. All the 3 patients after direct apposition of the fascia without using a polypropylene mesh suffered a recurrence (3 of 3; 100%). Significant risk factors for developing an incisional hernia were the amount of ascites and the stay in the ICU after transplantation. Neither severe deep nor superficial wound infection nor bowel fistulas were observed after implantation of a inlay/onlay mesh. CONCLUSION: In patients after liver transplantation, the implantation of a polypropylene mesh proved to be an efficient and safe method of treating incisional hernias. Implantation of a mesh was not associated with an increased infection rate, despite the use of immunosuppression. In view of the high recurrence rate associated with primary closure, mesh implantation should be given preference.

Female↗

PubMed2003

Does conversion of immunosuppressive monotherapy from cyclosporine A to tacrolimus improve bone mineral density in long-term stable liver transplant recipients?

The effects of converting cyclosporine A to tacrolimus on bone mineral density (BMD) have not yet been evaluated thoroughly in liver transplant patients. Interfering factors in this patient population often are concomitant glucocorticoid treatment or exposure to estrogens. Here, we investigated in a homogeneous population of 10 male liver transplant recipients the impact of converting low-dose cyclosporine A monotherapy to low-dose tacrolimus monotherapy on BMD by using dual-energy x-ray absorptiometry. During the 12-month study period, an increase in BMD at the lumbar spine was observed in 9 out of 10 men (P <.01), whereas BMD at the femoral neck remained stable. Converting cyclosporine A to tacrolimus appears to be safe and efficaceous with regard to maintaining or even increasing BMD in male liver transplant recipients.

Alkaline Phosphatase↗

PubMed2003

Bacteriobilia in percutaneous transhepatic biliary drainage: occurrence over time and clinical sequelae. A prospective observational study.

BACKGROUND: In the diagnosis and treatment of biliary disorders, establishing percutaneous transhepatic biliary drainage (PTBD) is an invasive procedure that can potentially lead to infectious complications in both the short and long-term. We therefore prospectively analysed the time course and spectrum of biliary bacteria in patients undergoing PTBD. METHODS: Forty-nine patients (19 F, 30 M; mean age 64 years) with malignant (65%) or benign (35%) biliary disorders were included, 20 of whom had a newly established PTBD (group A), while the remaining 29 had already had their PTBD in situ (group B) for a mean of 8 months. Bacteriological analyses of bile and blood were carried out, and clinical symptoms and laboratory values were obtained. RESULTS: Biliary bacteria were found in 60% of cases during the initial PTBD placement, and 24 h later this rate had already increased to 85%; two or more microorganisms were found in 40% initially and in 70% after a few days. At later PTBD exchanges, bacteriobilia was found in 100%, with all patients harbouring multiple organisms. Whereas the initial spectrum was mixed, Escherichia coli and enterococci (97% each), Klebsiella (73%) and Bacteroides species (37%) later predominated; Candida increased initially from 15% to 80%, but later decreased to 30%. Clinical signs of cholangitis were observed in 30% initially (no sepsis), but decreased to 6% at later exchanges. CONCLUSIONS: Bacteriobilia is initially a frequent, and later a regular, event in PTBD; however, clinically significant complications are rare during the long-term course and limited to the initial, more invasive, phase of PTBD. A knowledge of the bacterial spectrum is important for selecting appropriate antibiotic coverage if complications arise and/or major interventions such as surgery are planned.

Adult↗

PubMed2003

Biopsy surveillance is still necessary in patients with Barrett's oesophagus despite new endoscopic imaging techniques.

BACKGROUND AND AIMS: Endoscopic surveillance including stepwise four quadrant biopsies (4QB) is still regarded as the standard approach in patients with Barrett's oesophagus (BO). Several methods such as dye staining with methylene blue (MB) and tissue autofluorescence (AF) have been advocated to reduce the number of biopsies. We assessed their sensitivity and specificity compared with the standard approach-that is, endoscopy with 4QB-in the surveillance of a mixed BO population. PATIENTS AND METHODS: Thirty five consecutive BO patients (mean age 64.9 years; 30 men, five women) were included in the study. AF endoscopy was followed by high resolution video endoscopy (VE) plus tissue staining with 0.5% MB. Biopsies were taken from any suspicious area found on any of the above tests, in addition to 4QB every 2 cm. The results were classified as either positive or negative for the various tests used. Histopathological results were used as the reference standard. RESULTS: In the 35 study patients, a total of 345 biopsies showed low grade dysplasia (LGD) in 88 biopsies, high grade dysplasia (HGD) in 19 biopsies, and carcinoma in 12 biopsies. The sensitivity and specificity rates for AF and MB for the diagnosis of cancer or dysplasia versus BO mucosa without dysplasia were 21%/91% and 37%/91%, respectively. 4QB revealed five cancer/HGD areas and 76 LGD areas not detected by AF, MB, or VE. The additional yield of MB and AF over VE with 4QB concerned only one HGD area (in the vicinity of a cancer) and seven LGD areas. CONCLUSIONS: Due to their low sensitivity, AF and MB are not suitable techniques for reducing the high numbers of routine biopsies needed for finding additional foci of HGD or cancer. Careful endoscopic observation and stepwise four quadrant biopsy therefore still represent the gold standard for surveillance of Barrett's oesophagus.

Adenocarcinoma↗

PubMed2003

Neoadjuvant treatment with weekly high-dose 5-Fluorouracil as 24-hour infusion, folinic acid and oxaliplatin in patients with primary resectable liver metastases of colorectal cancer.

PURPOSE: To evaluate the efficacy and safety of neoadjuvant treatment comprising weekly high-dose 5-fluorouracil (5-FU) as a 24-hour infusion, folinic acid (FA) and biweekly oxaliplatin (L-OHP), followed by metastatic resection in patients with primarily resectable liver metastases of colorectal cancer (CRC). PATIENTS AND METHODS: 20 patients with primarily resectable liver metastases of CRC were enrolled in a prospective phase II study. On an outpatient basis, the patients received a treatment regimen comprising biweekly 85 mg/m(2) L-OHP in the form of a 2-hour intravenous infusion and 500 mg/m(2) FA as a 1- to 2-hour intravenous infusion, followed by 2,600 mg/m(2 ) 5-FU administered as a 24-hour intravenous infusion once weekly. A single treatment cycle comprised one infusion per week during a period of 6 weeks followed by a 2-week rest. Two cycles were administered, with a third being added when the treatment was well tolerated. Thereafter, curative resection of the liver metastases was attempted, and the patients were followed up. RESULTS: After neoadjuvant therapy, 2 of the original 20 patients showed complete remission (CR; 10%) and 18 patients partial remission (PR; 90%). As the main symptom of toxicity, diarrhea (CTC toxicity grade 3-4) was observed in 6 patients (30%), followed by vomiting in 3 patients (15%). The curative resectability rate was 80% (16 of 20). In 9 of 18 patients (50%) undergoing surgical intervention, mild postoperative complications, mainly wound healing disturbances (n = 5), occurred. No postoperative mortality was observed. Over a median follow-up of 23 months (12-38) 6 of 16 curatively resected patients developed distant metastases and 1 patient a local pelvic recurrence. The 2-year disease-free survival rate was 52% and the 2-year cancer-related survival rate 80%. CONCLUSION: The neoadjuvant treatment with weekly high-dose 5-FU in the form of a 24-hour infusion combined with FA and L-OHP is very effective and well tolerated. Surgical morbidity does not appear to be increased by the neoadjuvant treatment.

Aged↗

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↗