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Biomedical subjects

D C Dunn

Publications and source records attributed to D C Dunn.

At least 19 recordsLinked to original sources
PubMed1998

Changes in arginine, PAL activity, and nematode behavior in salinity-stressed citrus.

De novo arginine biosynthesis has been described as a response of citrus to a range of stresses. It is often noted that stress in plants enhances susceptibility to herbivory and pathogenic attack. Using a citrus and nematode (Tylenchulus semipenetrans) system, the effects of salinity stress on nematode behavior, amino acids (particularly arginine), and phenylalanine ammonia lyase (PAL) activity was investigated. The hypothesis was tested that under salinity stress, citrus grows more slowly and produces arginine in response to high levels of in vivo ammonia, resulting in lower PAL activity and increased susceptibility to nematode attack. After 30 days of high salinity (0.1 M NaCl), plants exhibited a 38% reduction in growth, 35% reduction in PAL activity, and had 54% higher infection rates. PAL activity was inversely correlated (P < or = 0.05) with salinity level and with increase in arginine concentration.

Animals↗
PubMed1997

Progress with cholecystectomy: improving results in England and Wales.

BACKGROUND: The Comparative Audit Service of the Royal College of Surgeons of England studied laparoscopic cholecystectomy in England and Wales during 1990-1991. The follow-on study undertaken during 1994 provides data to assess progress. METHODS: Pro formas were sent to consultant surgeons, requesting data on open and laparoscopic cholecystectomies performed in their units during 1994 with data on mean stay, mortality, complications, and the use of peroperative cholangiography and bile duct exploration. The identity of the consultants was treated confidentially. RESULTS: Data were provided by 110 surgeons on 4823 cholecystectomies (1019 open and 3804 laparoscopic) and outcome was compared with that of 3319 attempted laparoscopic and 8035 open cholecystectomies carried out during 1990-1991. The proportion of cases attempted laparoscopically rose from 27.2 per cent in 1990-1991 to 78.9 per cent in 1994, and conversion to open cholecystectomy rose from 5.3 to 6.7 per cent respectively. During 1994 peroperative cholangiography was undertaken in 22.9 per cent of laparoscopic and 44.6 per cent of open cases. Complication rates were similar in the two study periods, except the number of reported haemorrhagic complications was reduced by 40 per cent and bile duct injuries by fivefold (from 0.33 to 0.07 per cent). CONCLUSION: During 1994 the audit sampled approximately 10 per cent of all cholecystectomies performed in England and Wales. The results suggest progress in surgical techniques compared with findings in 1990-1991.

Cholangiography↗
PubMed1995

Presentation of comparative audit data.

The Royal College of Surgeons of England organizes a voluntary comparative audit service for its general surgical fellows. To date, the information from the audit has been presented purely descriptively, which does not take account of statistical variability and the effects of differences in case mix between the participants. A new approach to the presentation of these data, based on statistical modelling of the effects of case mix, is presented. The approach is illustrated in an application based on data relating to 136203 admissions reported by 110 surgeons. The result of adjusting for case mix is a substantial change in the relative performance of the participating surgeons, which demonstrates the folly of attempting to compare surgical performance on the basis of a measure as crude as the unadjusted mortality rate. Further development of the statistical modelling is required, but this new statistical approach appears to enhance greatly the credibility of the audit data, by quantifying its strengths and limitations.

Age Distribution↗
PubMed1995

Experience with 300 laparoscopic inguinal hernia repairs with up to 3 years follow-up.

The long-term results of 300 laparoscopic inguinal hernia repairs are reported with 11 cases followed up more than 3 years, 104 cases more than 2 years, and 225 cases more than 1 year. There were five early failures owing to the use of too small a piece of mesh. There have been no long-term recurrences. The results indicate that transabdominal preperitoneal laparoscopic mesh repair of hernias is a satisfactory technique with a low recurrence rate and a low major complication rate (4%). Patients have found the procedure to be remarkably pain free and 51% have taken no analgesics after discharge from hospital. Of the patients, 78% returned to work within 2 weeks of the operation. These results suggest that laparoscopic hernia repair can be performed safely with excellent long-term results.

Adolescent↗
PubMed1992

Comparative audit: an experimental study of 147,882 general surgical admissions during 1990.

In 1991, 1025 general surgical Fellows of The Royal College of Surgeons of England were circulated with a pro forma and asked to submit local audit results for admissions during 1990 to a confidential comparative audit service. The individual topics of cholecystectomy and colorectal resection were studied. Data returned by 160 surgeons concerned 147,882 admissions including 122,620 operations. Overall mortality rates ranged from 0 to 5 per cent and morbidity rates from 0 to 22 per cent. Laparoscopic cholecystectomy was associated with one-quarter of the mortality rate and two-thirds the morbidity rate of open cholecystectomy. Of the 33 surgeons who responded to a survey after the presentation of results, all wished to continue the exercise in future years; 39 per cent had been stimulated to perform further analyses and 15 per cent had changed practice habits as a result. Comparative audit involving large numbers of patients and surgeons is feasible and seems beneficial to participants.

Cholecystectomy↗
PubMed1992

Combined surgical audit by microcomputer involving units in four health regions.

General surgeons from hospitals in four well-separated health districts collected audit data about their patients using common software. They pooled their results in order to make comparisons between their practices. Data on 22,497 admissions including 17,473 operations were available. The data were found to be easy to collect and analyse using this program. There were significant differences in overall complication rates between the four centres, but these seem to be explained by differences in the emergency workload, case mix, and age range of the population treated. A study of inguinal hernia repairs and appendectomies showed low complication rates with no significant differences between centres, with the single exception of a higher incidence of wound problems in one centre. Because of the multiplicity of factors affecting them, complication rates could only be properly understood in a professional surgical context. Isolated figures would be open to damaging misrepresentation. Meetings between surgeons well armed with their own results seem to be the best way to forward the audit process.

Age Factors↗