Search PubMed⌕ Search

Biomedical subjects

C S Powell

Publications and source records attributed to C S Powell.

36 records · Page 2Linked to original sources
PubMed1997

Retrograde endoureteropyelotomy with the holmium:YAG laser. Initial experience.

OBJECTIVE: To evaluate the safety and efficacy of the holmium:YAG laser in the management of pelviureteric junction (PUJ) obstruction. PATIENTS AND METHODS: Between November 1994 and February 1996, 8 patients with 5 primary and 3 secondary PUJ obstructions underwent retrograde ureteroscopic holmium:YAG laser endopyelotomy. A 320- to 365-micron (Slimline, Coherent) fibre was used to deliver the laser energy. A posterolateral endopyelotomy was performed under visual monitoring. All patients had a ureteral stent left in place postoperatively for 6 weeks and a renogram was performed after 3 months. The mean follow-up was 12.4 months (3-24 months). RESULTS: Almost bloodless, accurate and layered division of the PUJ was easily performed. The average procedure time was 37.5 min. Our overall success rate was 87.5%. CONCLUSION: The holmium:YAG laser is a safe, reliable laser with adequate coagulative properties and precise cutting abilities. This allows a 'bloodless' operative field for controlled, accurate and safe endoscopic division of the PUJ.

Adult↗
PubMed1996

Bugs in the data?

Explore the source record for details and available documents.

Exobiology↗
PubMed1996

Circumcision: how do urologists do it?

OBJECTIVE: To determine the range of surgical techniques, analgesic practice, post-operative care and follow-up procedures used in the circumcision of children by urologists in the United Kingdom, and to suggest changes which would improve patient care and medical training in the relatively simple procedure of circumcision. MATERIALS AND METHODS: In 1994, all consultant urologists in the United Kingdom were sent detailed questionnaires asking about their practices in the circumcision of children. RESULTS: Of 308 urologists, 61% replied; of these, 55% use the sleeve-resection technique and 39% the free-hand method, and 57% use diathermy, half of which is bipolar. There is wide variation in the type of post-operative analgesia; 95% use an initial dressing but few recommend any subsequent dressing, 70% perform all circumcisions as day cases and 48% review patients in the clinic. There is significant concern that circumcision is not taught adequately to junior surgeons. CONCLUSION: The sleeve technique of resection should be more widely used. Analgesic practice could be improved with greater use of regional anaesthetics. Most urologists promote no specific care after discharge. There is probably a place for increasing the use of alternative procedures to circumcision.

Analgesia↗
PubMed1995

A new copolymerized composite resin system: a multiphased evaluation.

Most microfilled composite resins are relatively resistant to generalized wear; however, they commonly exhibit poor resistance to localized wear because of debonding of prepolymerized particles from the resin matrix. A copolymerized new composite resin, in which the filler particle trimethylolpropane-trimethacrylate is chemically bonded to the resin matrix, is evaluated. Epic-TMPT was subjected to both generalized and localized wear tests that revealed that its wear resistance was higher than that of other composite resin systems. Epic-TMPT in posterior occlusal cavities showed less than 8 microns of wear for each restoration, 1 year after placement. Placement of Epic-TMPT into large anterior abfraction lesions without mechanical retention, with surface etching, and subject to severe traumatic occlusion resulted in 87% retention 1 year after placement. In vivo usage biocompatibility tests demonstrated no pulpal irritation or inflammation when Epic-TMPT was placed on vital dentin of crown preparations with complete enamel removal.

Animals↗
PubMed1993

Comparison of seven commercial kits for detection of antibodies to Borrelia burgdorferi.

Five enzyme immunoassay (EIA) and two Western blot (WB) commercial kits were compared for their ability to detect antibodies to Borrelia burgdorferi. The panel of 53 test sera consisted of 25 sera positive for antibodies to Borrelia burgdorferi, 15 sera negative for such antibodies, 5 sera reactive in serologic tests for syphilis, and 8 sera containing antinuclear antibodies and/or rheumatoid factor. The rate of agreement with reference results was 93%, 90%, 90% and 88% for EIA kits from Diamedix, Cambridge Biotech, Mardx and Sigma respectively. The sensitivity and specificity was 84% and 100% respectively for Cambridge Biotech, 76% and 94% for Diamedix, 68% and 83% for Mardx, and 68% and 83% for Sigma. The three confirmatory tests, Cambridge Biotech WB, General Biometrics P39 EIA and Mardx WB, demonstrated 75%, 60% and 63% agreement respectively. The sensitivity and specificity was 52% and 100% respectively for Cambridge Biotech WB, 24% and 100% for General Biometrics P39 EIA, and 44% and 100% for Mardx WB. The results demonstrate the variable performance of commercial serologic kits for detection of antibodies to Borrelia burgdorferi. WB appears to be a better confirmatory test than the single protein EIA.

Antibodies, Bacterial↗
PubMed1993

Pulpal healing and dentinal bridge formation in an acidic environment.

This study was designed to observe the healing and bridging capacity of mechanically exposed pulps that were capped with silicate or zinc phosphate cements and biologically sealed with zinc oxide-eugenol cement to exclude bacteria. In six monkeys, Class V facial cavities with pulpal exposures were randomly distributed throughout 105 teeth, of which 80 were directly capped, 40 with silicate cement and 40 with zinc phosphate cement. Twenty of each group were filled to the cavosurface margin with the respective cement and 20 were surface sealed to the cavosurface margin with zinc oxide-eugenol cement. The remaining 25 exposures were capped with calcium hydroxide and amalgam as controls. Tissues were obtained by perfusion fixation after intervals of 21, 14, 10, 5 and 3 days. The 25 pulps capped with calcium hydroxide showed cell migration and organization at 5 days and dentinal matrix deposition at 10 days. At 3 and 5 days, all exposures in the experimental groups showed clot resolution. At 10 days, fibroblasts had stratified against the cement interface. At 14 days, pulps in both experimental groups showed new dentinal bridge formation directly adjacent to the acidic cements. The 21-day experimentally capped and sealed pulps presented healing similar to the controls. This study indicates that acidic components of silicate and Zinc phosphate cements are not directly responsible for pulpal inflammation or necrosis. The exposed dental pulp possesses an inherent healing capacity for cell reorganization and dentinal bridge formation when a bacterial seal is provided.

Animals↗
PubMed1991

Surgical management of renal cell carcinoma with extensive intracaval involvement using a venous bypass system suitable for rapid conversion to total cardiopulmonary bypass.

Renal cell carcinoma involves the vena cava in approximately 4% of the patients. Presently surgical extirpation is the only form of therapy that can result in cure. Recently management of extensive vena caval involvement has involved the use of cardiopulmonary bypass with circulatory arrest and hypothermia. We describe a technique using a venous bypass pump system (femoral vein to right atrium) for resection of renal cell carcinoma with suprahepatic vena caval extension (type II), which avoids the risks and complications of cardiac arrest and hypothermia but allows for rapid conversion to total cardiopulmonary bypass should the intraoperative need arise.

Aged↗
PubMed1989

Prostate specific antigen--a screening test for prostatic cancer?

A series of 287 patients referred by their family doctors with symptoms of bladder outflow obstruction were asked to attend the hospital for "pre-clinic" screening for carcinoma of prostate (CaP). Blood samples were collected from 211 patients and analysed for serum prostate specific antigen (PSA) and prostatic acid phosphatase (PAP). Thirty-six patients had a serum PSA greater than 10 micrograms/l and 7 had PAP levels greater than 5 iu/l. In no instance was the PAP elevated without an associated increase in PSA concentration. Patients with raised markers underwent further investigations which included prostatic biopsy and/or resection; 17 patients were proved to have carcinoma of the prostate, 9 of whom had distant metastases. The specificity of PSA for detecting prostate cancer in this study was 90% with a sensitivity of 89.5%, in contrast to values for PAP of 100% and 36.8%. The routine use of PAP as a marker for prostatic cancer should be abandoned. The use of PSA as a screening test in a group of patients with prostatism appears justified, but with a positive predictive value of only 47%, its use in a mass unselected screening programme is not recommended.

Acid Phosphatase↗
PubMed1988

An A-chain ricin immunotoxin targeted against rat class II major histocompatibility complex molecules. In vitro and in vivo effects.

Studies reported here have demonstrated that an antirat class II major histocompatibility complex molecule A-chain ricin immunotoxin could specifically remove, in a dose-dependent manner, the cells capable of stimulating the rat mixed lymphocyte reaction, an in vitro model of transplant rejection. It was further demonstrated that administration of a monoclonal antibody against class II major histocompatibility complex molecules to isolated rat pancreas grafts by hypothermic perfusion resulted in the targeting of cells bearing class II major histocompatibility complex molecules. But administration of the immunotoxin to isolated pancreases in a similar manner did not prolong their survival when allografted across a major histocompatibility barrier.

Animals↗
PubMed1981

Management of adult choledochal cysts.

A review of the English literature reveals a total of 1,337 patients with choledochal cysts. Improved diagnostic techniques to visualize the biliary system are demonstrating an increasing number of unsuspected choledochal cysts in adult patients. Either choledochal cysts remain clinically silent until adulthood or may develop in later life. Experience is reported with adult patients having type I, II, III, and IV choledochal cysts. Type I cysts are preferably managed by excision but cyst anatomy may necessitate choledochoenteric drainage. Type II cysts are treated by excision except for those located within the pancreatic portion of the common bile duct. These are best managed by transduodenal cystoduodenostomy. The type III cyst (choledochocele) should be excised carefully, identifying and preserving the common bile and pancreatic ducts. Type IV cysts include a combination of any one of the first three types of cyst plus the presence of intrahepatic cyst or cysts. Treatment of these cysts is dictated by the type and location of the extrahepatic cyst. Since choledochal cysts are being recognized with increased frequency in adults, surgeons need to be aware of the diagnostic and treatment modalities available for each type of biliary cyst.

Adult↗