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Biomedical subjects

M Evans

Publications and source records attributed to M Evans.

At least 325 records · Page 18Linked to original sources

Study of anti-DNA antibodies prepared by DNA cellulose or Cibacron blue chromatography.

We prepared anti-DNA antibodies from sera of lupus patients by either DNA cellulose or by Cibacron blue chromatography. Eluates from both columns were studied with respect to recovery of IgG, recovery, purification and specificity of anti-DNA activity. An attempt was made to raise rabbit anti-idiotypic antibodies against both eluates. DNA cellulose chromatography--if DNA leakage was prevented--yielded 58% recovery and 58-fold purification of the anti-DNA activity present in the original purified IgG sample. 1% of loaded IgG was recovered. Cibacron blue chromatography yielded 32% recovery and 1.1-fold purification of the anti-DNA activity. 29% of loaded IgG was recovered. Eluates of Cibacron blue were not pure as shown by their high binding activity against an unrelated antigen, tetanus toxoid. Eluates from DNA cellulose were pure and did not show anti-tetanus toxoid activity. Rabbit anti-idiotypic antibodies could be raised only against eluates of DNA cellulose suggesting that the eluates of Cibacron blue did not contain enough idiotypes to induce anti-idiotypic antibodies. The characterization of the rabbit anti-idiotypic antibodies showed that it contained two populations, one against site-specific idiotypes and the other against framework idiotypes. Anti-DNA antibodies prepared by Cibacron blue had idiotypes similar to those prepared by DNA cellulose. The present study demonstrates that DNA cellulose chromatography--if leakage of DNA is prevented--can yield excellent recovery and purification of anti-DNA activity. Anti-DNA antibodies prepared by DNA cellulose were enriched and could induce anti-idiotypic antibodies in rabbits. Tube chromatography on Cibacron blue yielded poor recovery and minimal enrichment of anti-DNA activity.

Animals↗

Randomized trial of oral adjuvant razoxane (ICRF 159) in resectable colorectal cancer: five-year follow-up.

Razoxane is one of the few agents which has shown activity in the treatment of advanced colorectal cancer. The drug has therefore been evaluated in a prospective randomized controlled trial as an adjuvant to surgery for resectable colorectal cancer. The results to median follow-up of 5 years are reported here. Accrual has ceased and a total of 272 patients entered the trial (133 control, 139 treatment). Treated patients received razoxane postoperatively on a continuous, long-term basis while control patients received identical clinical care but no adjuvant chemotherapy. Analysis of the results shows a significant prolongation of the time to recurrence for Dukes' C patients. All other groups including the overall analysis show no benefit although there is a consistent trend in favour of the treated patients except in Dukes' group 'D'. Razoxane is tolerated well by patients and causes minimal side-effects. However acute leukaemia occurred in three patients (2.45 per cent) after prolonged exposure to the drug and further evaluation should be in patients who are at high risk of developing recurrent cancer, in whom such a risk may be acceptable. It is concluded that razoxane is suitable for further evaluation in colorectal cancer and for incorporation into combination chemotherapy regimens.

Clinical Trials as Topic↗

Fluid sequestration: an early indicator of mortality in acute pancreatitis.

Complete daily intake and output charts were available for 218 patients with acute pancreatitis. The patients were divided into three groups according to the relation between fluid intake and output. In 105 patients in whom there was negligible fluid sequestration (daily output within 2 litres of intake) there were six deaths (5.8 per cent). In 69 patients the daily fluid intake exceeded the output by 2 litres or more but this imbalance lasted for 48 h or less; six patients died (8.7 per cent). The remaining 44 patients sequestered 2 litres or more of fluid per day for more than 48 h or until death. Thirty-eight patients in this group died (86.4 per cent). Fluid sequestration of 2 litres or more per day, and lasting longer than 48 h, is an accurate and simple predictor of mortality in acute pancreatitis. In this study it had a sensitivity of 76 per cent and a specificity of 96 per cent. The predictive value of a positive result was 86 per cent and of a negative result 93 per cent (efficiency 92 per cent).

Acute Disease↗

The prediction of abdominal surgical wound infection: the value of an enrichment broth for initial culture of operative parietal swabs.

At the conclusion of 817 abdominal operations, duplicate swabs were taken from the subcutaneous tissues for microbiological examination; one swab was transported to the laboratory in Stuart's thioglycollate medium and the other immediately incubated in Robertson's cooked meat broth. The latter method resulted in significantly more isolations of potentially pathogenic bacteria than the former, (31% compared with 17%, P less than 0.001). Immediate culture in broth with subsequent subculture allowed more accurate prediction of patients at risk of wound infection; using this method we found a 1:3 likelihood of wound infection with a 5% chance of severe infection when a single pathogenic species was cultured, and a 1:2 likelihood of wound infection with a 10% chance of severe infection when two or more pathogenic species were cultured. Transport of swabs in thioglycollate medium, in contrast, detected fewer patients with parietal contamination and showed a 1:5 likelihood of wound infection when the swab was sterile and a 1:2 chance when one or more than one pathogenic species was cultured.

Abdomen↗

Single-dose antibiotic prophylaxis of abdominal surgical wound infection: a trial of preoperative latamoxef against peroperative tetracycline lavage.

A randomized controlled clinical trial was undertaken in 542 consecutive emergency and elective abdominal operations, with one group of patients receiving tetracycline peritoneal and wound lavage and the other a single intravenous injection of 1 g latamoxef at induction of anaesthesia. Seventy-five patients were withdrawn because no potentially contaminated hollow viscus was opened, and a further 36 because they could not be assessed for wound infection. Of the remaining 431 patients, 212 received latamoxef resulting in 5 major and 8 minor wound infections in hospital; another 4 minor infections occurred at home (total incidence 8.0%). In the tetracycline group (n = 219) there were 7 major and 19 minor wound infections in hospital and 10 minor infections later (total incidence 16.4%). This is significantly higher than the rate with latamoxef (P = 0.012). Monitoring of operative and postoperative bleeding revealed no evidence (except in one doubtful case) of excessive bleeding associated with the use of a single dose of latamoxef. It is concluded that single-dose preoperative latamoxef is more effective than peroperative tetracycline lavage for the prevention of wound infections after potentially contaminated abdominal operations.

Abdominal Muscles↗

Effect of surface replacement arthroplasty on stability of the ankle.

Loosening after total ankle arthroplasty may result from absorption of tensile and shear forces by relatively small bone-cement interfaces. A surface replacement arthroplasty similar in principle to the Oxford knee arthroplasty offers theoretical advantages over other designs. The ability of such a prosthesis to provide a stable articulation was tested by examination of ankle laxity before and after replacement of the tibiotalar articular surfaces. The motion response characteristics of four specimens were measured for internal-external rotation moment (+/- 3 nm), inversion-eversion moment (+/- 3 nm), and anteroposterior displacement (+/- 50 N). The prosthesis restored normal internal-external and inversion-eversion rotatory stability, but the mean anteroposterior laxity was increased from 5.5 to 9.7 mm (P less than 0.05). Anteroposterior stability could not be restored by increasing the thickness of the bearing interposed between the prosthetic surfaces. The findings can be explained by consideration of the anatomy of the ligaments in relation to the contour of the normal and prosthetic articular surfaces. The normal tibial articular surface, which is concave in the sagittal plane, provides restraint against anteroposterior motion which is lost when the surface is replaced by the flat prosthetic surface. The findings question the suitability of this type of prosthesis for the ankle.

Ankle Joint↗

The prediction of incisional hernias by radio-opaque markers.

On the hypothesis that incisional defects occur soon after operation but the resulting hernia may not be diagnosed until months or years later, we attached three to five pairs of stainless steel haemostatic clips to the cut edges of the anterior aponeurosis during the closure of 59 major laparotomy incisions and X-rayed the abdomen one month later. Three patients were withdrawn and the remaining 56 were examined with special reference to incisional herniation at their six-month follow-up visit. The senior author subsequently arranged a series of extra clinics for surviving patients up to three years later (median 30 months after operation). He had no knowledge of the results of the abdominal X-rays when assessing whether or not the patient had a hernia. Six patients were found to have incisional hernias, and correlation with the measurements on the one-month X-rays showed separation of pairs of clips ranging from 12-70 mm (median 40). Three of the six hernias were discovered within seven months, the remaining three at 13, 28 and 29 months. In contrast none of the 50 patients without incisional hernias had more than 9 mm of separation of any pair of clips on the one-month X-ray. We conclude that the origins of incisional hernias can be traced back to events during the first month after operation and that they are not the result of later weakening of a well-healed laparotomy wound.

Hernia, Ventral↗

Evaluation of a computer assisted repeat prescribing programme in a general practice.

After introducing a computer assisted repeat prescribing programme into a south London practice improvements were made in several aspects of practice organisation. Time was saved by doctors and receptionists; prescriptions were produced more rapidly; information in the records about drugs that were available for repeat prescription was improved; and queries from chemists about prescriptions were reduced. The costs of the system in terms of computer operator time were estimated. Computerising prescribing data provides a source of data that may be used to enable doctors to audit their own prescribing.

Computers↗

A score system for evaluating random control clinical trials of prophylaxis of abdominal surgical wound infection.

We devised 33 rules for the evaluation of random control trials (RCT) and used them to assess 56 RCTs listed in Index Medicus during 1980-82 on antibiotic prophylaxis of surgical wound infection. We asked 15 questions about design and conduct, 10 about analysis and 8 about presentation. Out of a maximum score of 100 only 16 papers scored over 70, the highest being 89 and the lowest 34. Defects in presentation were not common, and 17 papers scored over 90 per cent. Defects in analysis included the incorrect use of statistical tests and ignoring the Type II error in 'negative' trials; only 13 papers scored over 70 per cent. Defects in design and conduct included transgressions of ethical principles, inappropriate regimens, ill-defined end points and biased randomization or assessment; only 20 papers scored over 70 per cent. We conclude that there is room for improvement in the performance of RCT and that the application of the 33 rules would be helpful not only to researchers but also to editors and referees of scientific journals, and to their readers.

Abdomen↗

Suction drainage of the gallbladder bed does not prevent complications after cholecystectomy: a random control clinical trial.

Some surgeons drain the gallbladder bed routinely, some selectively and some not at all. We aimed to clarify this confusion by entering 155 consecutive patients undergoing emergency and elective cholecystectomy without exploration of the common bile duct into a random control clinical trial. In 78 patients a 3 mm suction drain was left in the gallbladder bed and in 77 the abdomen was closed without drainage. There were no withdrawals, one death (in the drainage group) from myocardial infarction and one intraperitoneal abscess complicating postoperative pancreatitis (in the no-drainage group). Other events studied were postoperative pyrexia, wound infection, respiratory tract infection and duration of hospital stay. In none of these did the two groups differ either clinically or statistically. We conclude that drainage or non-drainage of the gallbladder bed must remain a matter of individual preference.

Aged↗

The screening of patients with suspected thyrotoxicosis using a sensitive TSH radioimmunoassay.

A radioimmunoassay was optimized to measure serum TSH with maximum sensitivity (sTSH). With this assay sTSH was less than 0.5 mIU/l in 100% of 64 patients with proven thyrotoxicosis and greater than 0.5 mIU/l in 92% of 76 normal subjects. sTSH correctly predicted the TSH response to TRH (delta TSH) in 93% of 125 patients with suspected thyrotoxicosis. In this group thyrotoxicosis was excluded by an sTSH greater than 0.5 mIU/l in 52% of patients thus avoiding the need for further testing.

Humans↗