Background: self-expanding metal stents are currently being used as a definitive palliative treatment for malignant colorectal obstruction in patients with incurable disease. Few studies have ...followed large numbers of patients from stent placement until death, and those few have reported conflicting results in the long-term clinical outcome data. Aims: this study evaluated the clinical effectiveness of stent placement for malignant colorectal obstruction throughout the patients' lives and related factors affecting stent patency, clinical success and complications. Methods: this was a multicentre, retrospective study of 89 consecutive patients who had undergone attempted expandable stent placement for symptomatic malignant colorectal obstruction during a 10-year period. Data were collected to analyse the sustained relief of obstructive symptoms throughout the patients' lives, as well as the technical success, immediate clinical success, stent patency, complications, reinterventions, survival, prognostic factors associated with stent patency and long-term clinical efficacy and risk factors for complications. Results: technical and immediate clinical success were achieved in 95.5% and 91.0% of patients, respectively. A total of 68 out of 89 patients (76.4%) maintained relief of obstruction from stent implantation until death without reintervention. Twenty patients (22.5%) had complications including perforation (n = 4; 4.5%), stent obstruction (n = 8; 9.0%), migration (n = 5; 5.6%) and haemorrhage (n = 3; 3.4%). Stent-related mortality was seen in 1 patient (1.1%). The estimated median survival and estimated mean stent patency were 87.0 and 322.7 days, respectively. In total, 12 of the initial 89 patients (13.5%) needed a colostomy for long-term relief of the obstructive symptoms. Univariate and multivariate analysis detected no significant prognostic factors associated with stent patency, long-term clinical efficacy and risk factors for complications; however, the multivariate logistic model revealed a non-significant trend by which the use of chemotherapy was a risk factor for migration (OR = 11.89; p = 0.06). Conclusions: for palliation of incurable malignant colorectal obstruction, expandable stents can provide sustained relief of obstruction in approximately 75% of patients. The procedure is associated with acceptable morbidity, need for reintervention and minimal mortality.
The hybrid cluster proteins from the sulfate reducing bacteria Desulfovibrio desulfuricans ATCC 27774 ( Dd) and Desulfovibrio vulgaris strain Hildenborough ( Dv) have been isolated and crystallized ...anaerobically. In each case, the protein has been reduced with dithionite and the crystal structure of the reduced form elucidated using X-ray synchrotron radiation techniques at 1.25 A and 1.55 A resolution for Dd and Dv, respectively. Although the overall structures of the proteins are unchanged upon reduction, there are significant changes at the hybrid cluster centres. These include significant movements in the position of the iron atom linked to the persulfide moiety in the oxidized as-isolated proteins and the sulfur atom of the persulfide itself. The nature of these changes is described and the implications with respect to the function of hybrid cluster proteins are discussed.
Clostridium thermocellum produces a highly organized multi‐enzyme complex of cellulases and hemicellulases for the hydrolysis of plant cell‐wall polysaccharides, which is termed the cellulosome. The ...bifunctional multi‐modular cellulase ctCel9D‐Cel44A is one of the largest components of the C. thermocellum cellulosome. The enzyme contains two internal catalytic domains belonging to glycoside hydrolase families 9 and 44. The C‐terminus of this cellulase, comprising a polycystic kidney‐disease module (PKD) and a carbohydrate‐binding module (CBM44), has been crystallized. The crystals belong to the tetragonal space group P43212, containing a single molecule in the asymmetric unit. Native and seleno‐l‐methionine‐derivative crystals diffracted to 2.1 and 2.8 Å, respectively.
The introduction of normal phases into the superconducting phases is one of the most efficient forms to improve the pinning center densities and the critical current densities J/sub c/ of ...superconductors. Controlled generation of pinning centers with a projected distribution can contribute to estimate the pinning forces and mechanisms acting on the flux lines and to determine procedures to improve J/sub c/. The introduction of nanometric-scale Cu regions into the Nb filaments region during the fabrication of Cu-Nb (or Cu-Nb/sub 3/Sn) composite superconductors changes the properties of the superconducting phase, mainly due to the proximity effect. The present work shows the development and characterization of Cu-Nb composites prepared by successive bundlings followed by swaging and wire drawing, leading to dimensions of the Cu regions as small as 43 nm. The samples were characterized by SEM and by the measurements of electrical resistivity as a function of temperature, critical temperatures T/sub c/, J/sub c/ vs. H, and F/sub p/ vs. H, in different steps of deformation and different dimensions of Cu and Nb, in comparison to the superconducting coherence length /spl xi/. The results helped to determine the influences of the Cu presence and of the proximity effect on the superconducting properties, leading to important conclusions useful to the optimization of J/sub c/ in superconductors.
The incidence of lymphocele after renal transplantation varies between 0.6 and 18% of cases, and many factors have been associated to its etiology. Cellular rejection of the kidney allograft has been ...described as a possible causal factor of lymphocele.
To analyze the possible relationship between lymphocele and acute cellular rejection.
A retrospective study.
A referral hospital center.
170 patients submitted to kidney transplantation from March 1992 to January 1997. A standard technique for renal transplantation was used.
Of the 19 patients that developed lymphocele, 16 presented at least one episode of acute cell rejection (84%), and were treated with methylprednisolone. The relation between lymphocele and rejection was statistically significant (p = 0.04). Treatment of lymphocele consisted of peritoneal marsupialization in 3 patients (15.3%), percutaneous drainage in 7 (36.8%), laparoscopic marsupialization in 2 (10.5%), and conservative treatment in 7 patients (36.8%). Evolution was favorable in 15 patients (78.9%), 1 patient (5.3%) died due to a cause unrelated to lymphocele, and 3 (15.8%) lost the graft due to immunological factors. The average follow-up period was 24.5 months.
The high incidence of acute cell rejection in patients with lymphocele suggests a possible causal relationship between both conditions.
: The aim of this study was to verify if dialysis solution volumes used in patients on continuous ambulatory peritoneal dialysis (CAPD) interfere with pulmonary function and if the pulmonary volumes ...interfere with the lymphatic absorption of the peritoneal cavity. We submitted 10 CAPD patients with a mean age of 48 ± 18 years and on CAPD for 35 ± 27 months to the following evaluations: first, measurement of the lymphatic absorption from the peritoneal cavity; second, measurement of the hydrostatic intraperitoneal pressure; and third, expirometry with the peritoneal cavity full of dialysis solution and empty. There were no differences between the expirometry results obtained with the peritoneal cavity full and empty of dialysis solution, and the results were in accordance with the prediction for this population. The values did not correlate with the peritoneal lymphatic absorption of the peritoneal cavity. The cumulative lymphatic absorption of the peritoneal cavity after 4 h dialysis solution permanence was 197 ± 93 ml, and the hydrostatic intraperitoneal pressure was 13.9 ± 2.8 column centimeters of water. Neither of these correlated with pulmonary volumes. In conclusion, CAPD did not interfere with the pulmonary function, nor did the pulmonary function influence the lymphatic absorption of the peritoneal cavity of these patients.
BACKGROUND: It has been reported that patients with acute renal failure (ARF) requiring haemodialysis show an improved recovery of renal function when the dialysis treatment is performed using a ...biocompatible membrane rather than a bioincompatible membrane. However, most recent published human trials have not been able to confirm these findings. METHOD: Over a 2-year period, we prospectively studied 53 patients with ARF after cadaver renal transplantation who required haemodialysis and randomized them into two treatment groups. One group underwent dialysis with a cuprophane membrane and the other group underwent haemodialysis with a more biocompatible membrane, polysulfone. All patients received an immunosuppressive regimen which included azathioprine, prednisone and cyclosporine. RESULTS: There was no difference by patient characteristics or immunosuppressive regimen before acute tubular necrosis (ATN) recovery. In both groups the number of haemodialysis sessions required prior to the recovery of renal function (6.57+/-2.79 vs 6.05+/-2.40), the number of oliguric days (16.25+/-5.14 vs 14.40+/-4.67) and the number of hospital days (33.38+/-12.85 vs 30.10+/-11.00), were not statistically different. There was also no difference in long-term allograft outcome. CONCLUSION: Our data demonstrate that the use of a more biocompatible membrane had no influence on the recovery from acute renal failure after renal transplantation.
To evaluate 2 versions of a computerized surgical videokeratoscope that measures a central region of the cornea of approximately 4.0 to 6.0 mm in diameter to provide information on dioptric power and ...astigmatism.
Grupo de Optica Oftalmica Universidade de São Paulo, and Departamento de Oftalmologia da Escola Paulista de Medicina, São Paulo, Brazil.
The first videokeratoscope system with 10 Placido rings is based on a 15 000 fiber-optic illuminated disk attached to the objective lens of a surgical microscope. With this system, the light intensity can be adjusted during surgery for better contrast of the Placido image. The second system with 14 Placido rings is based on a neon light source behind the Placido disk. With both systems, a 480 × 640 pixel resolution charge-coupled device camera and an IBM-compatible personal computer frame grabber were used. Image processing was used for boundary detection of the rings. An axial curvature algorithm based on the spherical surfaces was used to calculate the dioptric power for each examination. Measurements of 4 real spherical surfaces and 4 simulated aspheric surfaces (ellipsotoric surfaces with different apical radii and different shape factors) were performed.
Twenty corneas of 10 healthy volunteers were measured on both videokeratoscope systems and an EyeSys System 2000 corneal topographer. The root- mean-square error for the spherical and simulated aspheric surfaces was, respectively, less than 0.20 diopter (D) and 1.30 D for the 10-disk videokeratoscope system and less than 0.16 D and 1.40 D for the 14-disk system. The mean deviation in corneal measurements with both systems was 0.09 mm for the radius of curvature, 0.51 D for dioptric power, and 5 degrees for cylinder.
The results indicate that the 2 surgical videokeratoscopes are sufficiently precise to aid the anterior segment surgeon in reducing residual astigmatism in cataract surgery and keratoplasty.
A hypothetical model for the non-physiological electron transfer complex between cytochrome c553 (c553) and the flavodoxin (fld) from the sulphate-reducing bacteria Desulfovibrio vulgaris has been ...recently published 1 based on rigid-body docking and refined by molecular dynamics. In this study, the functional validity of this model is tested by looking at the role of electrostatics in the non-physiological interprotein electron transfer between the two proteins at different ionic strengths. The results are compared with the electron transfer between fld and cytochrome c from horse heart (hhc). Second-order rate constants (k2) were measured for both non-physiological systems at different ionic strengths: a complex, bell-shaped behaviour is observed for the k2 of the c553/fld redox pair with an optimum rate at I=58 mmol l(-1), whereas under the same conditions the k2 for hhc/fld decreased monotonically with increasing ionic strength. Results from the electron transfer kinetics are rationalised in terms of reorganisational effects of an ensemble of conformations of the electron transfer competent c553/fld complexes, consistent with the published model.
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