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Biomedical subjects

A G McKenzie

Publications and source records attributed to A G McKenzie.

At least 19 recordsLinked to original sources
PubMed2005

Current management of patients taking herbal medicines: a survey of anaesthetic practice in the UK.

BACKGROUND AND OBJECTIVES: Increasing numbers of patients taking herbal medicine products are presenting for anaesthesia and surgery. Anaesthetists need to consider the perioperative implications of herbal medicines and should, therefore, have some knowledge of this subject. METHODS: A postal questionnaire survey was sent to a random 5% of practising members of the Association of Anaesthetists of Great Britain and Ireland residing in the UK, to identify attitudes, practice and knowledge regarding herbal medicines. RESULTS: From 341 questionnaires there were 221 replies, a 65% response rate. Ninety per cent stated that they seldom or never asked patients about herbal medicine usage, yet 65% felt that there could be potentially harmful effects of herbal medicines in the perioperative period. There was a very poor level of knowledge with respect to the current management of 10 well-known herbal medicines. However, 75% agreed that information about perioperative usage of herbal medicines is important, and 77% felt that herbal medicines should be in the undergraduate medical curriculum. Reading was the usual source of herbal medicine product information. Most (82%) felt their knowledge of herbal medicine products and the implications in patient care were inadequate. CONCLUSIONS: This sample of anaesthetists require education on herbal medicines. Suggestions for remedial action are given.

Anesthesia↗
PubMed2001

The N-terminal globular domain and the first class A amphipathic helix of apolipoprotein A-I are important for lecithin:cholesterol acyltransferase activation and the maturation of high density lipoprotein in vivo.

To investigate the role of the N terminus of apolipoprotein A-I (apoA-I) in the maturation of high density lipoproteins (HDL), two N-terminal mutants with deletions of residues 1-43 and 1-65 (referred to as Delta 1-43 and Delta 1-65 apoA-I) were studied. In vitro, these deletions had little effect on cellular cholesterol efflux from macrophages but LCAT activation was reduced by 50 and 70% for the Delta 1-43 and Delta 1-65 apoA-I mutants, respectively, relative to wild-type (Wt) apoA-I. To further define the role of the N terminus of apoA-I in HDL maturation, we constructed recombinant adenoviruses containing Wt apoA-I and two similar mutants with deletions of residues 7-43 and 7-65 (referred to as Delta 7-43 and Delta 7-65 apoA-I, respectively). Residues 1-6 were not removed in these mutants to allow proper cleavage of the pro-sequence in vivo. Following injection of these adenoviruses into apoA-I-deficient mice, plasma concentrations of both Delta 7-43 and Delta 7-65 apoA-I were reduced 4-fold relative to Wt apoA-I. The N-terminal deletion mutants, in particular Delta 7-65 apoA-I, were associated with greater proportions of pre beta-HDL and accumulated fewer HDL cholesteryl esters relative to Wt apoA-I. Wt and Delta 7-43 apoA-I formed predominantly alpha-migrating and spherical HDL, whereas Delta 7-65 apoA-I formed only pre beta-HDL of discoidal morphology. This demonstrates that deletion of the first class A amphipathic alpha-helix has a profound additive effect in vivo over the deletion of the globular domain alone (amino acids 1-43) indicating its important role in the production of mature alpha-migrating HDL. In summary, the combined in vitro and in vivo studies demonstrate a role for the N terminus of apoA-I in lecithin:cholesterol acyltransferase activation and the requirement of the first class A amphipathic alpha-helix for the maturation of HDL in vivo.

Adenoviridae↗
PubMed2000

Prelude to pancuronium and vecuronium.

The discovery of the neuromuscular blocking activity of malouetine isolated from Malouetia bequaertiana Woodson by Quevauviller and Lainé in 1960 stimulated interest in aminosteroids as potential neuromuscular blockers. Alauddin (a pharmacist) and Martin-Smith (a medicinal chemist) began research in this area, which was then taken up by pharmaceutical companies. Pure pancuronium was synthesised in 1964 by Savage and his co-workers, directed by Hewett. Pharmacologists headed by Buckett discovered that pancuronium was far more potent than d-tubocurarine and had minimal side-effects. Buckett quickly recognised the value of pancuronium, and his persistence resulted in successful clinical trials, followed by the commercial launch of pancuronium in 1968. Vecuronium was synthesised, tested and the studies published by Buckett, Hewett and Savage in 1973, but this was before anaesthetists called for a 'clean muscle relaxant' and, furthermore, it was unstable in aqueous solution. Hence, it was only promoted for clinical trials six years later.

History, 20th Century↗
PubMed2000

The inventions of John Blease.

Though he had no formal training in engineering, John Blease of Merseyside invented numerous devices that greatly benefited the practice of anaesthesia. Starting with the turning of component parts for simple anaesthetic machines in the 1930s, he was introduced to clinical anaesthesia and became skilled in the art of dental anaesthesia. In the early 1940s he developed the all-purpose Alfo-Blease anaesthetic machine. In 1945 he designed an intermittent positive pressure ventilator, which was used successfully around Liverpool. After World War II he improved this into the Blease 'Pulmoflator', which was the first British positive-pressure ventilator in commercial production. From then until the early 1960s he patented many other inventions, duly utilized in the manufacture of anaesthetic equipment, in which industry the Blease name survives in the company he founded.

Anesthesiology↗
PubMed1998

Operative obstetric mortality at Harare Central Hospital 1992-1994: an anaesthetic view.

A prospective review of anaesthetic-associated deaths (AAD) was undertaken at the maternity unit of Harare Central Hospital, Zimbabwe, for the triennium 1992-1994. AAD was defined as death within 24 h of anaesthesia or failure to regain consciousness. Three groups of avoidable factors (obstetric, anaesthetic and administrative) were considered, and a scoring system used to allocate one avoidability point for each death with avoidable factors. Out of 9833 operative procedures (91% under general anaesthesia) there were 22 AADs. Avoidable factors were identified in 17 deaths (77%). Seven deaths were directly attributable to anaesthesia. Haemorrhage was the commonest cause of death, accounting for 10 cases. Common factors, identified in all instances of substandard anaesthetic and obstetric care, were emergency cases and lack of senior involvement. The problems are discussed and also viewed in the context of overall maternal mortality (outcome period 42 days). The mortality data are compared with those from the UK and some hospitals in South Africa. It is concluded that improvements in resources, education, guidelines and monitoring are necessary if the mortality rate is to be reduced.

Journal Article↗
PubMed1996

Interpleural local anaesthesia: anatomical basis for mechanism of action.

India ink was injected through an extradural catheter placed in the right interpleural space in cadavers at autopsy. The lung was removed and the spread of the ink noted and photographed. In six cadavers, block sections were cut at the anterior axillary line through three ribs, intercostal muscles and parietal pleura. The blocks were fixed in formalin and then decalcified, sectioned, stained and mounted on slides. In all cases the ink covered the chest wall, lung and diaphragm, and was seen to pool in the paravertebral area. Examination of the histological slides revealed black pigment on the pleural surface and in the subpleural space. The mechanism of transport across the parietal pleura is discussed.

Adult↗
PubMed1996

Mortality associated with anaesthesia at Zimbabwean teaching hospitals.

OBJECTIVE: To determine and analyse peri-operative mortality with particular emphasis on avoidable factors, in the hope that this information will lead to an improvement in standards. DESIGN: Review of all anaesthetic-associated deaths (AADs) during the year 1992. All available records were scrutinised and further information was obtained from mortality meetings and confidential discussions. SETTING: Harare Central and Parirenyatwa hospitals, which are referral centres. PATIENTS: Out of 34,553 subjects presenting for surgical procedures, there were 89 deaths between 1 January and 31 December 1992. MAIN OUTCOME MEASURES: Incidence of AAD, avoidable mortality rate (AMR) and classification of avoidable surgical, anaesthetic and administrative factors. MAIN RESULTS: The incidence of AAD per 1,000 anaesthetics was 2.58. (AAD was defined as death within 24 hours of anaesthesia or failure of a patient, who was previously conscious, to regain consciousness.) There were avoidable factors in 45 (51%) of the deaths. The overall AMR was 1.34 per 1,000 operations (death classified as avoidable if mismanagement contributed to mortality). The AMR (surgical), AMR (anaesthetic) and AMR (administrative) were 0.80, 0.33 and 0.21 respectively. Scoring in each category of avoidability was done proportionately, with a maximum of one point per death awarded where there were avoidable factors). The commonest avoidable factors (in order of frequency) were uncontrolled haemorrhage, poor postoperative management, poor pre-operative management and anastomotic dehiscence. CONCLUSIONS: This audit reveals that there were avoidable factors in 51% of peri-operative deaths. It should be possible to reduce the mortality rate by developing preventive measures.

Adolescent↗
PubMed1996

Intensive therapy for chloroquine poisoning. A review of 29 cases.

OBJECTIVE: To obtain a data base of the features of chloroquine poisoning and to assess existing intensive therapy for it. DESIGN: Retrospective review of all confirmed cases of acute chloroquine poisoning admitted to intensive care between November 1990 and October 1994. All available records were scrutinised. SETTING: The intensive care units of Harare Central and Parirenyatwa hospitals, which are referral centres in Harare. PATIENTS: Selection of patients depended on positive confirmation of chloroquine ingestion. Cases of concomitant ingestion of other drug(s) were not excluded. MAIN OUTCOME MEASURES: Cardiac arrest or not; death or survival to discharge from hospital. MAIN RESULTS: Of a total of 29 patients, aged 16-51 years, 69% (20) were female and 31% (9) male. The commonest clinical features were respiratory failure, depressed level of consciousness, hypothermia, hypotension, cardiac arrest and hypokalaemia. Eleven patients had at least one cardiac arrest; 5 of these were successfully resuscitated. Management included gastric lavage, intravenous diazepam, mechanical ventilation when necessary, and occasionally inotropic infusions. Four patients suffered cardiac arrest during gastric lavage. There were 6 deaths (mortality 20.7%). CONCLUSIONS: This study indicates the common clinical features of acute chloroquine poisoning. A survival rate of about 80% is being achieved by intensive therapy at Harare Central and Parirenyatwa Hospitals. Rapid utilisation of the treatment regimen described should reduce the mortality to less than 10%.

Acute Disease↗