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Biomedical subjects

Michael McDonald

Publications and source records attributed to Michael McDonald.

At least 19 recordsLinked to original sources
PubMed2007

Ethical dilemmas in veterinary medicine.

Veterinarians frequently encounter situations that are morally charged and potentially difficult to manage. Situation involving euthanasia, end-of-life care, economics, and inadequate provision of care create practical and moral dilemmas. Ethical tension may be attributable to differences in beliefs regarding the moral value of animals, client and veterinary responsibilities, and deciding what is best for an animal. Veterinarians can employ communication skills used in medical situations to explore the reasons underpinning ethical dilemmas and to search for solutions with clients, staff, and colleagues.

Animal Welfare↗
PubMed2006

Cystic adventitial disease of the femoral vein presenting as deep vein thrombosis: a case report and review of the literature.

Cystic adventitial disease of veins is a rare condition. We report the case of a 28-year-old man who presented with a swollen leg secondary to obstruction of the common femoral vein as a result of this disease. He underwent excision of the cyst and made a full recovery. The presentation, investigation, treatment and pathology of this condition is discussed.

Adult↗
PubMed2005

A vector expressing feline mature IL-18 fused to IL-1beta antagonist protein signal sequence is an effective adjuvant to a DNA vaccine for feline leukaemia virus.

DNA vaccination using vectors expressing the gag/pol and env genes of feline leukaemia virus (FeLV) and plasmids encoding feline interleukin-12 (IL-12) and IL-18 completely protected cats from viraemia following challenge [Hanlon L, Argyle D, Bain D, Nicolson L, Dunham S, Golder MC, et al. Feline leukaemia virus DNA vaccine efficacy is enhanced by coadministration with interleukin-12 (IL-12) and IL-18 expression vectors. J Virol 2001;75:8424-33]. However, the relative contribution of each cytokine gene towards protection is unknown. This study aimed to resolve this issue. IL-12 and IL-18 constructs were modified to ensure effective expression, and bioactivity was demonstrated using specific assays. Kittens were immunised intramuscularly with FeLV DNA and various cytokine constructs. Together with control kittens, these were challenged oronasally with FeLV and monitored for 15 weeks. All six kittens given FeLV, IL-12 and IL-18 were protected from the establishment of persistent viraemia and four from latent infection. Of six kittens immunised with FeLV DNA and IL-18, all were protected from viraemia and five from latent infection. In contrast, three of five kittens given FeLV DNA and IL-12 became persistently viraemic. Therefore, the adjuvant effect on the FeLV DNA vaccine appears to reside in the expression of IL-18.

Adjuvants, Immunologic↗
PubMed2005

Tissue localization and frequency of antigen-specific effector CD4 T cells determines the development of allergic airway inflammation.

Previous activation of effector Th2 cells is central to the development of allergic inflammatory responses. We have observed that priming of allergen-specific Th2 cells in C57BL/6 or B10.A mice with allergen delivered via the i.p. or s.c. routes results in very different outcomes following subsequent airway exposure to the same allergen. Systemic allergen immunization (via the i.p. route) resulted in the formation of a lung-resident population of allergen-specific T cells, and mice developed severe allergic airway inflammation in response to inhaled allergen. The localization of cells to the lung did not require the presence of antigen at this site, but reflected a large pool of circulating activated allergen-specific T cells. In contrast, localized immunization (via the s.c. route) resulted in a small T-cell response restricted to the draining lymph node, and mice were not responsive to inhaled allergen. These data indicate that prior sensitization to an allergen alone was not sufficient for the induction of allergic inflammation; rather, responsiveness was largely determined by precursor frequency and tissue localization of the allergen-specific effector Th2 cells.

Amino Acid Sequence↗
PubMed2005

Chinese Canadian beliefs toward organ donation.

The authors' purpose in this study is to explore the values and beliefs regarding organ donation of Chinese Canadians. Data collection involved individual interviews (n = 15) and focus groups. The major organizing categories were the importance of context, and values and beliefs. The context included little knowledge about donation and possible influence of spiritual or cultural values. Lack of communication and the need to preserve an intact body were themes that emerged in relation to death and dying. In relation to organ donation, most participants thought it was "a noble deed," but fears about organ donation were similar to those reported in other studies. It is important to note the considerable diversity in beliefs among these participants.

Adult↗
PubMed2005

Indo-Canadian beliefs regarding organ donation.

CONTEXT: There is concern that a disproportionately high number of people of South Asian origin await transplantation in Canada. The donation rate is low in this population, and it is difficult to obtain good tissue matches. OBJECTIVE: To explore the values and beliefs regarding organ donation among Indo-Canadian people living in British Columbia. DESIGN: A naturalistic qualitative study was designed. Individual interviews and focus groups were held to collect data pertaining to beliefs regarding organ donation. SETTING: Lower Mainland of British Columbia, Canada. PARTICIPANTS: A total of 40 Indo-Canadian persons participated; a wide range of ages, religions, and backgrounds were represented. RESULTS: The major themes that emerged from the data related to context (including family/community, religion, trust in the healthcare system, and knowledge about organ donation); and values and beliefs (including intergenerational considerations, death and dying, and the organ donation process). Participants noted that people from their community were reluctant to discuss death and relatedissues such as organ donation. Although there was recognition of the importance of individual decision making pertaining to organ donation, the participants believed that family and community members also should be involved. CONCLUSIONS: Beliefs varied considerably among participants, and one should not make assumptions about the beliefs of any one individual based primarily on that individual's membership in an ethnocultural community.

Adolescent↗
PubMed2005

Research ethics across the 49th parallel: the potential value of pilot testing "equivalent protections" in Canadian research institutions.

Canada and the United States share the world's largest trade partnership and an increasing concern about divergent regulatory approaches to common industries. Canadian research institutes receive more research funding from the U.S. National Institutes of Health than any other country, much of it to fund multi-centre and collaborative research between the two countries. Because of these close economic and research ties, and the extensive similarities between the two countries in the review and oversight of ethics in human subjects research, we propose that Canada would be an ideal country for a pilot-test of the feasibility of "equivalent protections," a U.S. regulation that permits comparison of protections for human subjects between institutions in the two countries. The "equivalent protections" has been advocated by various bodies in the United States as a potentially beneficial mechanism for improving oversight of foreign trials. As well, we argue that "equivalent protections" could prove to be valuable for Canada in five specific ways: (1) by potentially reducing administrative burden on Canadian research institutions administering U.S. federal research funding; (2) by creating symbolic value of an explicit recognition by the United States that procedures normally followed for the protection of human subjects in Canadian research institutions are at least equivalent to those provided by the U.S. regulations; (3) by lowering the opportunity cost of investing in research in Canada; (4) by affording Canada an opportunity to enhance its leadership role in international research by offering an alternative to the U.S. regulatory model for the protection of human subjects; and (5) by providing a model for how the idea of equivalent protections might be addressed for research funded by Canadian agencies but conducted in other countries.

Canada↗
PubMed2004

Expanding the three Rs to meet new challenges in humane animal experimentation.

The Three Rs are the main principles used by Animal Ethics Committees in the governance of animal experimentation, but they appear not to cover some ethical issues that arise today. These include: a) claims that certain species should be exempted on principle from harmful research; b) increased emphasis on enhancing quality of life of research animals; c) research involving genetically modified (GM) animals; and d) animals bred as models of disease. In some cases, the Three Rs can be extended to cover these developments. The burgeoning use of GM animals in science calls for new forms of reduction through improved genetic modification technology, plus continued attention to alternative approaches and cost-benefit analyses that include the large numbers of animals involved indirectly. The adoption of more expanded definitions of refinement that go beyond minimising distress will capture concerns for enhancing the quality of life of animals through improved husbandry and handling. Targeting refinement to the unpredictable effects of gene modification may be difficult; in these cases, careful attention to monitoring and endpoints are the obvious options. Refinement can also include sharing data about the welfare impacts of gene modifications, and modelling earlier stages of disease, in order to reduce the potential suffering caused to disease models. Other issues may require a move beyond the Three Rs. Certain levels of harm, or numbers and use of certain species, may be unacceptable, regardless of potential benefits. This can be addressed by supplementing the utilitarian basis of the Three Rs with principles based on deontological and relational ethics. The Three Rs remain very useful, but they require thoughtful interpretation and expansion in order for Animal Ethics Committees to address the full range of issues in animal-based research.

Animal Experimentation↗
PubMed2004

The arch index: a measure of flat or fat feet?

BACKGROUND: Studies using footprint-based estimates of arch height have indicated that obesity results in a lowered medial longitudinal arch in children. However, the potentially confounding effect of body composition on indirect measures of arch height, such as the arch index, has not been investigated. METHODS: This study assessed the body composition of 12 male and 12 female adults (mean age: 39.9 +/- 8.1 years, height: 1.724 +/- 0.101 m; weight: 95.1 +/- 13.7 kg, and BMI: 31.9 +/- 3.0 kg/m(2)) using bioelectrical impedance analysis to produce a two-component model of fat mass (FM) and fat-free mass (FFM). The dynamic arch index also was determined from electronic footprints captured during gait using a capacitive pressure distribution platform with a resolution of 4 sensors/cm(2). RESULTS: While significant correlations were noted between FFM and the area of both the hindfoot (r =.75, p <.05) and forefoot (r =.72, p <. 05), the midfoot area was correlated only with FM (r =.54, p <.05). Similarly, the arch index was significantly correlated with the FM percentage (r =.67, p <.05). CONCLUSIONS: The findings of this pilot study suggest that body composition influences arch index values in overweight and obese subjects. Consequently, body composition may be a confounding factor in interpreting footprint based estimates of arch height and, as such, these estimates would best be used with supplementary measures of body composition.

Adipose Tissue↗
PubMed2004

Rationale for a new generation of indicators for coastal waters.

More than half the world's human population lives within 100 km of the coast, and that number is expected to increase by 25% over the next two decades. Consequently, coastal ecosystems are at serious risk. Larger coastal populations and increasing development have led to increased loading of toxic substances, nutrients and pathogens with subsequent algal blooms, hypoxia, beach closures, and damage to coastal fisheries. Recent climate change has led to the rise in sea level with loss of coastal wetlands and saltwater intrusion into coastal aquifers. Coastal resources have traditionally been monitored on a stressor-by-stressor basis such as for nutrient loading or dissolved oxygen. To fully measure the complexities of coastal systems, we must develop a new set of ecologic indicators that span the realm of biological organization from genetic markers to entire ecosystems and are broadly applicable across geographic regions while integrating stressor types. We briefly review recent developments in ecologic indicators and emphasize the need for improvements in understanding of stress-response relationships, contributions of multiple stressors, assessments over different spatial and temporal scales, and reference conditions. We provide two examples of ecologic indicators that can improve our understanding of these inherent problems: a) the use of photopigments as indicators of the interactive effects of nutrients and hydrology, and b) biological community approaches that use multiple taxa to detect effects on ecosystem structure and function. These indicators are essential to measure the condition of coastal resources, to diagnose stressors, to communicate change to the public, and ultimately to protect human health and the quality of the coastal environment.

Animals↗
PubMed2004

Dignity at the end of our days: personal, familial, and cultural location.

The desire to be treated with dignity, particularly at the end of one's life, is a fairly universal preference found in most cultures. Such treatment requires positive actions of respect in the behaviour of others toward the dying and the dead. It also involves negative actions, particularly refraining from doing "dignatory harms" to the dead and the dying. Yet it is not always easy for clinicians and researchers who deal with the dying and dead to decide on appropriate action or inaction. I suggest that such decision making can be helped by locating the dying person along three dimensions: the personal, the familial, and the cultural. These elements are interrelated in complex ways that need to be unpacked in context. Thus, one person may locate herself within a familial context while a sibling may locate himself against that context. While locating individuals along the three dimensions suggested does not "solve" ethical problems, it should help clinicians in understanding and dealing more compassionately with the dead, the dying, their families, and their communities.

Attitude of Health Personnel↗
PubMed2004

Aboriginal beliefs about organ donation: some Coast Salish viewpoints.

A large number of Aboriginal people await transplantation, and reluctance to donate organs has been noted among Aboriginal people. The purpose of this study was to explore the values and beliefs regarding organ donation of Coast Salish people living in British Columbia, Canada. Interviews were held with 14 people (8 women and 6 men) ranging in age from 25 to 63 years. Contextual themes were: lack of trust, life in Aboriginal communities, and tension between contemporary and traditional perspectives. Themes pertaining to death and dying were: acceptance of fate, death routines/rituals, and body wholeness. Themes pertaining to organ donation were: "we don't talk about it," transfer of spirit, and helping others. There was considerable diversity in beliefs among participants, which suggests that the beliefs held by an individual Aboriginal person should not be assumed to reflect those of any specific Aboriginal community.

Adult↗
PubMed2003

Physician specialty and quality of care for CHF: different patients or different patterns of practice?

BACKGROUND: Previous reports have suggested that internists employ evidence-based care for congestive heart failure (CHF) less frequently than cardiologists. Reasons for this possible difference are unclear. METHODS: A retrospective review of 185 consecutive patients admitted to a Canadian tertiary care facility between April 1998 and March 1999 with a primary diagnosis of CHF and who were treated by internists (IM group) or cardiologists (CARD group) was conducted. RESULTS: The CARD group (n=65) was younger (70 versus 76 years, P<0.001) and had larger left ventricular end-diastolic diameter by echocardiography (57 versus 51 mm, P=0.006) than the IM group (n=120). The CARD group documented ejection fraction in 90% of cases versus 54% in the IM group (P<0.05). There was no difference in angiotensin-converting enzyme (ACE) inhibitor usage (68% versus 63%, P=0.48) or optimal ACE dosage (CARD 50% versus IM 42%, P=0.44). Multivariate predictors of ACE inhibitor usage were serum creatinine, male sex, peripheral edema and increasing serum glucose. The CARD group had higher usage of beta-blockers (69% versus 49%, P<0.009), lipid lowering medication (35% versus 17%, P<0.004) and warfarin therapy for atrial fibrillation (74% versus 28%, P<0.005). CONCLUSION: The data suggest that Canadian cardiologists and internists use ACE inhibitors equally and care for a relatively similar group of CHF patients. However, beta-blockade, warfarin, lipid lowering therapy and documentation of critical data occurred more frequently under cardiologist care. The possibility that there may be a gradation of adoption of newer guidelines for CHF care according to physician specialty is raised.

Adrenergic beta-Antagonists↗
PubMed2002

No decrease in incidence of atrial fibrillation in patients undergoing off-pump coronary artery bypass grafting.

BACKGROUND: With the introduction of beating heart surgery, there has been a renewed interest in the incidence of postoperative atrial fibrillation (AF) in patients undergoing coronary artery bypass grafting (CABG). A small number of studies have reported markedly decreased incidences of postoperative AF in patients undergoing off-pump CABG. AIMS: The aim of the present study was to review the incidence of AF in patients undergoing off-pump CABG at Royal Melbourne Hospital. METHODS: A retrospective review was undertaken of 80 patients who had elective first-time CABG off-pump over a 16-month period. These patients were matched with 80 patients who underwent CABG with cardiopulmonary bypass (CPB). Data on preoperative and operative variables were collected. Incidences of postoperative AF in both groups were recorded. RESULTS: The incidence of AF in the off-pump group was 27 of 80 patients (34%) and in the CPB group it was 25 of 80 patients (31%; NS). Increasing age was a significant risk factor for developing postoperative AF, and beta-blockade was identified as a protective factor. CONCLUSIONS: Off-pump CABG does not decrease the incidence of postoperative atrial fibrillation. A randomised prospective trial has been commenced at Royal Melbourne Hospital to further investigate postoperative outcomes of off-pump CABG.

Journal Article↗