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Biomedical subjects

D Oliver

Publications and source records attributed to D Oliver.

At least 91 records · Page 5Linked to original sources

Synchronous combined oesophagectomy: a review of 20 cases.

Twenty patients with carcinoma of the oesophagus treated by a modification of the Ivor Lewis oesophagectomy using two surgeons working synchronously were reviewed. All the patients had carcinomas of the middle or lower thirds of the oesophagus. The median age was 68 years. There were 17 males and 3 females. Average total operating time was 3 h 40 min. There was one peri-operative death. The median length of stay was 15 days. The synchronous combined approach to oesophagectomy has advantages, which are discussed, similar to synchronous combined abdomino-perineal resection of the rectum.

Adenocarcinoma↗

Preparation and biokinetic evaluation of various halogenated iminodiacetic acid-type compounds labeled with technetium-99m for hepatobiliary scintigraphy in the baboon (Papio ursinus) model.

In an evaluation of various 99mTc-labeled halogenated (F, Cl, Br, I) iminodiacetic acid (IDA) derivatives for hepatobiliary scintigraphy, it was found that, in the baboon model, none of these compounds performed as well as did disida. F-IDA was least effective, with the lowest biliary excretion and highest renal participation, but multihalogen substitution as in penta-F-IDA increased the biliary specificity and reduced urinary excretion to the extent that penta-F-IDA scored second to disida and even above I-IDA, with its high molecular weight. Surprising also was the relatively good performance of Cl-IDA compared to Br-IDA and I-IDA.

Animals↗

SecA protein, a peripheral protein of the Escherichia coli plasma membrane, is essential for the functional binding and translocation of proOmpA.

We have reconstituted protein translocation across plasma membrane vesicles of Escherichia coli using purified proOmpA and trigger factor, a 63 kd soluble protein. Treatment of membrane vesicles with urea inactivates them for translocation unless a factor present in cytoplasmic extracts is added during the translocation reaction. Sedimentation analysis showed that the stimulatory activity is of distinctly higher mol. wt than trigger factor. Cytoplasmic extracts from a strain that greatly overproduces the SecA protein are highly enriched in the stimulatory activity for untreated membranes and restore translocation to urea-treated membranes, suggesting that this protein is the stimulatory factor. This assay was used to monitor the isolation of SecA protein from the overproducing strain. The purified protein is soluble, yet binds peripherally to membranes with high affinity and supports translocation. Using pure proOmpA, SecA protein, trigger factor and urea-treated membranes, the protein export process was resolved into binding and translocation steps. We find that proOmpA binds to membrane vesicles with or without SecA protein, but that translocation only occurs when SecA was bound prior to proOmpA.

Amino Acid Isomerases↗

SecA protein hydrolyzes ATP and is an essential component of the protein translocation ATPase of Escherichia coli.

Bacterial protein export requires two forms of energy input, ATP and the membrane electrochemical potential. Using an in vitro reaction reconstituted with purified soluble and peripheral membrane components, we can now directly measure the translocation-coupled hydrolysis of ATP. This translocation ATPase requires inner membrane vesicles, SecA protein and translocation-competent proOmpA. The stimulatory activity of membrane vesicles can be blocked by either antibody to the SecY protein or by preparing the membranes from a secY-thermosensitive strain which had been incubated at the non-permissive temperature in vivo. The SecA protein itself has more than one ATP binding site. 8-azido-ATP inactivates SecA for proOmpA translocation and for translocation ATPase, yet does not inhibit a low level of ATP hydrolysis inherent in the isolated SecA protein. These data show that the SecA protein has a central role in coupling the hydrolysis of ATP to the transfer of pre-secretory proteins across the membrane.

Adenosine Triphosphatases↗

Papillo-renal syndrome. An inherited association of optic disc dysplasia and renal disease. Report and review of the literature.

A family is described in which the father and son had chronic renal disease of early onset and bilateral optic nerve dysplasia. A further son, known to have microphthalmos died of renal disease in childhood. Optic nerve changes included coloboma in the father and Handmann's optic nerve anomaly, a condition resembling the morning glory syndrome (M.G.S.), in the son. There was electrodiagnostic and visual field evidence of optic nerve dysfunction even where acuity was relatively unaffected. The son developed central serous retinopathy, a condition frequently encountered in association with optic nerve dysplasias, including M.G.S.

Adult↗

Usage of statistics in the surgical literature and the 'orphan P' phenomenon.

The statistics used in 240 surgical publications were reviewed. Basic parametric statistics were used in 60% of the publications; 21% of publications failed to document a measure of central tendency, 11% of publications contained an undefined '+/-' notation, and 10% of publications did not state the type of evaluative statistic that was used to calculate a P value, that is, an 'orphan P'. These results indicate the need for wider education about the use of descriptive and basic parametric statistics. It is impossible to evaluate the surgical literature critically without these skills.

Australia↗

SecA suppresses the temperature-sensitive SecY24 defect in protein translocation in Escherichia coli membrane vesicles.

Genetic analysis of protein secretion in Escherichia coli has identified secY/prlA and secA as components of the secretory apparatus. We have examined the roles of the secY(prlA) gene product (an integral membrane protein) and the soluble secA gene product in translocation of OmpA and alkaline phosphatase precursors in an in vitro system. The protein translocation defect of the secY24 mutation was recently demonstrated in vitro as was its suppression by an S300 extract. We show here that the extract was essentially inactive in SecY24 suppression when SecA protein was removed from it by immunoaffinity chromatography. Furthermore, purified SecA protein suppressed the SecY24 defect. Preincubation of the inactivated SecY24 membrane vesicles either with S300 containing SecA or with purified SecA protein reconstituted the membranes and restored the translocation activity when assayed in the absence of additional soluble proteins. These results suggest that the SecY24 translocation defect is suppressed by SecA interacting, directly or indirectly, with SecY24 on the cytoplasmic membrane.

Bacterial Proteins↗

Competition among physicians. Avoiding anticompetitive activities.

Increases in both the cost of medical care and the numbers of providers have generated strong pressure for competition in the medical profession. The Federal Trade Commission strives to maintain such competition free from public and private restraints in order to maximize consumer welfare. The author describes the advantages of these types of competitive practices and discusses the competitive restraints that most concern the FTC: restrictions on ethical advertising, exclusion of competitors, restraints on dispensing drugs, and restrictions on commercial practice locations.

Advertising↗

Outcome in patients on continuous ambulatory peritoneal dialysis and haemodialysis: 4-year analysis of a prospective multicentre study.

In a study in seven large renal units in England, the morbidity and mortality of all patients starting continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis during 1983-85 were monitored prospectively over a 4-year period and related to reasons for choice of therapy and potential risk factors. 610 new patients (median age 52 years, range 3-80 years) started CAPD; 16% had diabetes mellitus and 21% cerebrovascular or cardiovascular disease. 329 patients (median age 48 years, range 5-77 years) started haemodialysis; 7% had diabetes mellitus and 17% cerebrovascular or cardiovascular disease. The Kaplan-Meier patient survival estimates at 4 years were 74% for haemodialysis and 62% for CAPD; technique survival figures for the same period were 91% for haemodialysis and 61% for CAPD. Cox's proportional hazards regression analysis showed that cerebrovascular/cardiovascular disease, age over 60 years, and diabetes mellitus were important predictors for survival in CAPD patients; there were no risk factors associated with permanent change to haemodialysis. In the haemodialysis group early change to CAPD was associated with presence of cerebrovascular or cardiovascular disease. The major cause of drop-out in both groups was transplantation. The mean length of hospital admission was 14.8 days per patient-year for CAPD and 12.4 days per patient-year for haemodialysis.

Adolescent↗

Multi-centre study on outcome of treatment in patients on continuous ambulatory peritoneal dialysis and haemodialysis.

In a multi-centre study by seven large renal units in the United Kingdom, the morbidity and mortality of all patients starting CAPD and haemodialysis during a 2-year period (1983-1984) has been monitored prospectively and related to reasons for choice of therapy and potential risk factors. Over this period 338 new patients (mean age 48; range 3-77 years) started CAPD; 17% had diabetes mellitus and 25% had cerebro/cardiovascular disease. One hundred and seventy-five patients (mean age 45; range 5-73 years) started haemodialysis; 6% had diabetes mellitus and 14% had cerebro/cardiovascular disease. The Kaplan-Meier actuarial patient survival estimates at 2 years were haemodialysis 84% and CAPD 83%, whilst technique survival figures for the same period were haemodialysis 92% and CAPD 80%. Cox's regression analysis showed that cerebro/cardiovascular disease and age greater than 60 years were most important predictors for survival in CAPD patients, in whom smoking appeared to be a significant risk factor, for permanent change of therapy to haemodialysis. The major cause of 'drop out' in both groups was transplantation, whilst hospitalisation was 14.9 days per patient year for CAPD and 12.8 for haemodialysis patients. Within the CAPD group a temporary change to haemodialysis (less than 2 months) occurred on 106 occasions (each of mean of 19 days duration), amounting to 10 days per patient year of therapy. CAPD was used twice as often as haemodialysis for managing new patients. After 2 years hospitalisation technique and patient survival were comparable in the two groups, with cerebro/cardiovascular disease, age, and smoking being significant predictors of outcome.

Adolescent↗

Multicenter seroepidemiologic study of the impact of cytomegalovirus infection on renal transplantation.

The effects of cytomegalovirus (CMV) infection on patient and allograft survival were determined in 1245 renal transplant recipients from 46 transplant centers. When an antilymphocyte preparation was administered to cadaveric allograft recipients, those at risk for primary CMV had a worse outcome than similar patients treated with prednisone and azathioprine (53.1% alive at 6 months with a functioning allograft vs. 70.8%, P = .05) or patients at risk for reactivation CMV (53.1% vs. 71.1%, P = .035). Patients at risk for reactivation CMV had a better outcome if they received an antilymphocyte preparation (71.1% vs. 60.8%, P less than .01). The type of immunosuppression had no effect on patients without CMV. Living-related donor transplantation was not significantly influenced by CMV or type of immunosuppression. We conclude that CMV infection is strongly influenced by the form of immunosuppression employed, and that both are important determinants of the outcome of cadaveric renal transplantation.

Age Factors↗