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Biomedical subjects

John C Hall

Publications and source records attributed to John C Hall.

13 recordsLinked to original sources
PubMed2003

A prospective randomized trial of enteral glutamine in critical illness.

OBJECTIVE: To assess the influence of enteral glutamine on the incidence of severe sepsis and death in critically ill patients. DESIGN: This two-armed clinical trial was triple blind (patients, attending staff, research nurse). SETTING: The 10 bed general ICU at Royal Perth Hospital, Western Australia. PATIENTS: This trial evaluated 363 patients requiring mechanical ventilation (median APACHE II score=14); of these, 85 had trauma. INTERVENTION: The intervention solution contained 20 g/l glutamine and the control solution was isojoulic and isonitrogenous. MEASUREMENTS AND RESULTS: The groups had similar characteristics at baseline, and they also received equivalent amounts of protein and energy. Patients in the glutamine group received a median of 19 g/glutamine per day and 91% (332 of 363) of the patients were fed via a nasogastric tube (median duration=10 days). The outcomes were similar in the two groups: (a) death within 6 months: glutamine group 15% (27 of 179) vs control group 16% (30 of 184); p=0.75; relative risk, 0.95 (95% confidence interval, 0.71-1.28); and (b) severe sepsis: glutamine group 21% (38 of 179) vs control group 23% (43 of 184); p=0.62; relative risk, 0.94 (95% confidence interval, 0.72-1.22). There was also no discernable difference in the secondary outcomes relating to infections, febrile period, antimicrobial therapy, and consumption of inotropes. CONCLUSION: This clinical trial did not support the use of enteral glutamine supplements in similar cohorts of critically ill patients.

Adult↗
PubMed2003

Glutathione.

Glutathione (GSH) is an ubiquitous thiol-containing tripeptide that plays a key role in cell biology. It modulates cell response to redox changes associated with the reactive oxygen species, detoxifies the metabolites of drugs; regulates gene expression and apoptosis, and is involved in the transmembrane transport of organic solutes. Polymorphism has been observed in key enzymes of GSH metabolism and some alleles have been associated with an impaired redox buffer system downsteam diseases, and susceptibility to ischaemia. These varied activities make GSH an attractive target for a more reductionist approach to the prevention and management of many conditions of interest to surgeons.

Glutathione↗
PubMed2002

Imagery practice and the development of surgical skills.

BACKGROUND: The purpose of this review is to explore the potential role of imagery practice during the acquisition of surgical skills, imagery practice being the mental rehearsal of a skill. METHODS: The core of this review is derived from a literature search of a computer database (Medline). FINDINGS: The cognitive processing that occurs during times of intense learning involves processes such as dream enactment behavior and imagery practice. These processes complement and augment the more usual forms of practice. CONCLUSIONS: Imagery practice provides a mechanism for the explicit learning of surgical skills.

Education, Medical↗
PubMed2002

The internet: from basics to telesurgery.

The exponential growth in information technology is resulting in a rapid increase in the ability to develop useful applications on the Internet. The purpose of the present article is to provide a brief review of the Internet with a consideration of its relevance to surgeons. This review is intended to indicate a range of relevant issues, rather than to discuss any specific topic in depth. It is becoming difficult for surgeons to reach their full potential unless they exploit Internet-based activities. This is because the ability to rapidly capture information of quality is an essential ingredient in a reflective approach to surgical problems. More futuristic is the prospect of using computer-based technology to operate upon patients from a distance (telesurgery).

Humans↗
PubMed2002

Dendritic cells.

Dendritic cells (DC) are the most effective or 'professional' of the antigen-presenting cells (APC) that initiate primary immune responses. They are located at surveillance sites where they capture and process antigens. They then initiate and regulate T- and B-cell responses by expressing lymphocyte costimulatory molecules, migrating to lymphoid organs and secreting biologically active molecules. Dendritic cells not only activate lymphocytes to induce the immune response, but they also minimize autoimmune reactions by tolerizing T cells to self-antigens. Recent Phase I and II clinical studies have shown promise in the use of antigen-pulsed autologous DC for vaccination of cancer patients. Dendritic cells also have applications in preventing rejection after transplantation, immunization against viral infections and immunosuppression in autoimmune diseases.

Antigen-Presenting Cells↗
PubMed2002

Baseline comparisons in surgical trials.

INTRODUCTION: Baseline measurements are an essential component of clinical trials. They should establish that the groups involved are clinically equivalent so that any observed differences can be attributed to the intervention under evaluation. The objective of this study was to review the use of baseline comparisons in surgical trials. METHODS: A standardized format was used to evaluate 206 surgical trials published within 10 prestigious journals between January 1997 and December 1999. RESULTS: One hundred and fifty-one (73%) of the trials used the first table in the article to record baseline data. More than one-quarter of the trials declared less than five items and one-third of the trials inappropriately used 'P-values' as a measure of baseline equivalence. Only nine of the 54 multicentre studies (17%) mentioned the individual centres as possible confounding factors. DISCUSSION: Greater attention needs to be paid to baseline comparisons in surgical trials. One way of developing this type of critical ability is to use a checklist while reading a surgical trial of interest. Good resources include the CONSORT Statement by a group of prominent international biostaticians and the CLEAR (Critical Literature Evaluation and Research) Courses run by the Royal Australasian College of Surgeons.

Clinical Trials as Topic↗
PubMed2002

The Surgical Research Society of Australasia.

BACKGROUND: The Surgical Research Society of Australasia (SRS) was established in 1961. The main intent was to promote surgical research, especially by young surgeons. The 50th Scientific Meeting of the SRS is due to be held in 2002. METHODS: Selected information was extracted from the programme books for the scientific meetings of the SRS, while historical material was retrieved from the Records and Archives Unit of the Royal Australasian College of Surgeons. RESULTS: There have been 48 scientific meetings of the SRS between 1962 and 2000 inclusive, which have included the presentation of 1627 free papers. Forty-one percent of the presenters (325/784) have done so on more than one occasion. The content of the presentations reflects the changing nature of surgical research during the last several decades. CONCLUSIONS: The SRS has achieved its original intent of promoting surgical research.

Australia↗
PubMed2002

Cysteinyl leukotrienes induce IL-4 release from cord blood-derived human eosinophils.

BACKGROUND: Eosinophils contain preformed stores of IL-4 within their cytoplasmic granules, but physiologic stimuli to release IL-4 from eosinophils are not yet defined. OBJECTIVE: We evaluated whether cysteinyl leukotrienes (CysLTs) could elicit IL-4 release from eosinophils. METHODS: We used a dual-antibody capture and detection assay (EliCell) for IL-4 release and used eosinophils differentiated in vitro from human cord blood-derived progenitors. RESULTS: Leukotriene (LT) C4, LTD4, and LTE4 each elicited the rapid, vesicular transport-mediated, dose- and time-dependent release of IL-4 from eosinophils. Both LTD4 and LTE4 evoked similar and earlier IL-4 release than LTC4. LTC4 did not act directly but only after conversion to LTD4 because an inhibitor of gamma-glutamyl transpeptidase, acivicin, blocked LTC4-induced IL-4 release. MK571 and LY171833, receptor antagonists for CysLT1 and not CysLT2, and pertussis toxin inhibited LTC4-, LTD4-, and LTE4-induced IL-4 release. Cord blood-differentiated eosinophils contained CysLT1 protein detectable by means of immunoblotting. CONCLUSION: CysLTs acting through G(i) protein-coupled and MK571- and LY171833-inhibitable receptors on cord blood-derived human eosinophils can act as autocrine or paracrine mediators to stimulate the rapid, nonexocytotic release of preformed IL-4.

Acetophenones↗
PubMed2002

Randomization in surgical trials.

BACKGROUND: There are concerns that use of the term "randomized" conveys a form of legitimacy to surgical trials that may sometimes be inappropriate. The objective of this study was to review the nature and use of randomization techniques in surgical trials. METHODS: We evaluated aspects of the randomization process in 619 surgical trials published within 10 prestigious journals between January 1990 and December 1999. RESULTS: Only 33% of the published trials (202/619) adequately described a valid randomization process. Furthermore, 78% (484/619) did not declare the use or extent of a blinding technique and almost two-thirds of the published trials failed to state how they concealed the randomization process. CONCLUSIONS: Our study indicates that many published surgical trials ignore basic aspects of the randomization process. It is difficult for surgeons to have faith in trials that fail to demonstrate an unbiased allocation of patients and ignore the need to maintain some confidentiality about the allocation of patients into groups.

Humans↗
PubMed2002

The management of patients with the short bowel syndrome.

The surgeon is invariably the primary specialist involved in managing patients with short bowel syndrome. Because of this they will play an important role in co-ordinating the management of these patients. The principal aims at the initial surgery are to preserve life, then to preserve gut length, and maintain its continuity. In the immediate postoperative period, there needs to be a balance between keeping the patient alive through the use of TPN and antisecretory agents and promoting gut adaptation with the use of oral nutrition. If the gut fails to adapt during this period, then the patient may require therapy with more specific agents to promote gut adaptation such as growth factors and glutamine. If following this, the patient still has a short gut syndrome, then the principal options remain either long term TPN, or intestinal transplantation which remains a difficult and challenging procedure with a high mortality and morbidity due to rejection.

Adaptation, Physiological↗
PubMed2000

The omentum.

Explore the source record for details and available documents.

Journal Article↗
PubMedDate not supplied

Influence of glycine on intestinal ischemia-reperfusion injury.

BACKGROUND: It has been reported that glycine may protect donor small intestine against hypothermic ischemia before transplantation. This is consistent with the documented role of glycine as a natural cytoprotectant. OBJECTIVE: Using an in vivo rodent model, we sought to determine whether exposure to a 20% glycine solution reduces the extent of warm ischemia-reperfusion injury. METHODS: Wistar rats (n = 50) underwent laparotomy. A baseline group did not receive any further intervention. The remaining animals had cannulation of the aorta before the initiation of intestinal ischemia (30 minutes) followed by reperfusion (30 minutes). Using a factorial design, rats were randomized to receive local tissue perfusion with either normal saline or a 20% glycine solution during either the preischemia or the prereperfusion phase. Standardized segments of small intestine were removed at the end of the study period to determine the extent of ischemia-reperfusion injury. RESULTS: Perfusion with 20% glycine increased mucosal protein content (p < .05), increased mucosal DNA content (p < .05), reduced intestinal myeloperoxidase activity (p < .05), and maintained mucosal glutaminase activity. This was true regardless of whether glycine was administered during the preischemia phase or the prereperfusion phase. CONCLUSIONS: Local perfusion with 20% glycine can diminish warm ischemia-reperfusion injury to the rat small intestine in an in vivo model. The role of glycine supplementation should be evaluated in situations where hemodynamic instability may be responsible for breakdown in the gut barrier.

Animals↗