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Biomedical subjects

C MacDougall

Publications and source records attributed to C MacDougall.

12 recordsLinked to original sources
PubMed2001

Preoperative prediction of prolonged mechanical ventilation following coronary artery bypass grafting.

OBJECTIVE: Few studies have attempted to evaluate who would require prolonged mechanical ventilation following heart surgery. The objectives of this study were to identify predictors of prolonged ventilation in a large group of coronary artery bypass grafting (CABG) patients from a single institution. METHODS: One thousand, eight hundred and twenty-nine consecutive patients undergoing CABG were reviewed retrospectively and evaluated for preoperative predictors of prolonged ventilation which included: age, gender, ejection fraction (EF), renal function, diabetes, angina status, New York Heart Association Class, number of diseased vessels, urgency of the procedure, re-operation, chronic lung disease (COPD) and intraoperative variables such as IABP, inotropes, stroke and myocardial infarction. Prolonged ventilation was defined as > or = 24 h. Stepwise logistic regression analysis was performed. RESULTS: Patients were on average 65.4+/-10.6 years of age, 30% were diabetic, 80% had triple vessel disease and 93% were of functional class III/IV. The mean ejection fraction was 60+/-16 percent. Overall peri-operative mortality was 2.7%. There were 157 patients that required prolonged ventilation with a peri-operative mortality of 18.5% (P < 0.001). Preoperative independent predictors of prolonged ventilation were found to be: unstable angina (OR 5.6), EF < 50 (OR 2.3), COPD (OR 2.0), preop. renal failure (OR 1.9), female gender (OR 1.8) and age > 70 (OR 1.7). Based on these predictors, a model was created to estimate of the risk of prolonged ventilation in individual patients following CABG with results ranging from < or = 3% in patients without any risk factors to > or = 32% in patients with five or more independent risk factors. Certain intraoperative variables were strong predictors of prolonged ventilation and included: stroke (OR 12.3), re-operation for bleeding (OR 6.9) and perioperative MI (OR 5.8). CONCLUSION: We were able to create a stable model where several preoperative and intra-operative variables were shown to be predictive of prolonged ventilation after CABG surgery. The ability to identify patients at increased risk for prolonged ventilation may allow the development of pre-emptive strategies and more effective resource allocation.

Age Factors↗
PubMed2001

Concurrent opioid dependence and mental health problems: a review of the issues for general practice.

The literature is reviewed on the issue of concurrent opioid dependence and mental health problems within the general practice setting. People with such problems have poorer personal, clinical and social outcomes than people with either mental health or drug and alcohol (D&A) problems alone. Mental health and drug services operate from different policy systems and are generally not co-ordinated with each other, leaving the onus on the patient to move effectively through health systems. The common statement that GPs are ideal health professionals to manage concurrent problems is contrasted with the evident barriers in general practice such as lack of time, knowledge, skills and confidence. Models for managing concurrent problems tend towards shared care. However, these models either have received mixed evidence (e.g. consultant-liaison psychiatry) or are amenable to development but remain untested (e.g. co-ordinated care, community health centre programs). The Enhanced Primary Care items introduced in 1999/2000 may provide an incentive for GPs to participate in shared care arrangements with other health professionals. However, there is a need for mechanisms to increase the links between GPs and other health services.

Australia↗
PubMed2001

Planning and recruiting the sample for focus groups and in-depth interviews.

In this article, the authors address the importance of sampling and recruiting for focus groups and in-depth interviews. They draw on a synthesis of the literature and their research experience and propose a three-stage checklist summarizing strategies that worked for them and addressed some of the problems described in the literature. The strategies proposed involve the three stages of prepare, contact, and follow-up. The prepare stage involves finding information sources and key contacts or champions, discovering related projects, and drafting alternative samples. The contact stage involves negotiation with key contacts and potential participants, confirmation, and plans for continued involvement. The follow-up stage involves feedback and continuing links in public events, action, and advocacy resulting from the research. The preparation and follow-up stages can require considerable time and resources, which, if not available within grants, can be provided through partnerships with community agencies or by seeking supplementary resources.

Evaluation Studies as Topic↗
PubMed2001

The Booroola (FecB) phenotype is associated with a mutation in the bone morphogenetic receptor type 1 B (BMPR1B) gene.

Genetic variations in ovulation rate which occur in different breeds of sheep provide useful models to explore the mechanisms regulating the development of antral follicles. The Booroola gene, an autosomal mutation that affects ovulation rate, has been known for over two decades and despite intensive research it has not yet been identified. Using resources from human genome mapping and known data about gene linkage and chromosome location in the sheep, we selected the gene encoding the Bone Morphogenetic Protein receptor (BMPR) type 1 B (ALK-6) as a candidate site for the mutation. The BMPR1B gene in the human is located at the region linked with the Booroola mutation, syntenic to chromosome 6 in the sheep. A fragment of the sheep BMPR1B gene was cloned from an ovarian cDNA and the deduced aminoacid (AA) sequence is over 98% homologous to the known mammalian sequences. cDNA and genomic DNA from 20 Booroola genotypes were screened and two point mutation were found in the kinase domain of the receptor, one at base 746 of the coding region (A in the ++ to a G in FF animals) which results in a change from a glutamine in the wild type to a arginine in the Booroola animals. Another point mutation was identified at position 1113, (C to A) but this mutation does not change the coding aminoacid. The first mutation was confirmed in genomic DNA from 10 ewes from an independent Brazilian flock which segregates the Booroola phenotype. In all instances homozygous FecB gene carrier (n=11) had only the 746 A to G mutation, non gene carriers (n=14) had only the wild type sequence and heterozygote gene carriers (n=5) had both sequences. This mutation in the subdomain 3 of the kinase domain could result in an alteration in the expression and/or phosphorylation of SMADs, resulting in the phenotype characteristic of the Booroola animals which is the 'precocious' development of a large number of small antral follicles resulting in increased ovulation rate.

Amino Acid Sequence↗
PubMed2000

Interaction of the Arabidopsis polycomb group proteins FIE and MEA mediates their common phenotypes.

Genes of the FERTILISATION INDEPENDENT SEED (FIS) class regulate cell proliferation during reproductive development in Arabidopsis [1-5]. The FIS genes FERTILISATION INDEPENDENT ENDOSPERM (FIE) and MEDEA (MEA) encode homologs of animal Polycomb group (Pc-G) proteins, transcriptional regulators that modify chromatin structure and are thought to form multimeric complexes [3-11]. To test whether similarities in fis mutant phenotypes reflect interactions between their protein products, we characterised FIE RNA and protein localisation in vivo, and FIE protein interactions in yeast and in vitro. Expression of FIE mRNA overlaps with that of MEA during embryo sac and seed development and is unaffected in mea mutants. Results from the yeast two-hybrid system and an in vitro pull-down assay indicate that MEA and FIE proteins interact. The relevance of this interaction in vivo is supported by the finding that FIE and MEA co-localise in the nucleus in transfected plant cells. Interaction of MEA and FIE is mediated by the amino-terminal region of MEA. Despite sequence divergence in this domain, MEA can interact with its corresponding animal partner Extrasexcombs (ESC) in the yeast two-hybrid system. We conclude that FIE and MEA act together as part of a multimeric complex and that this accounts for the similarities in mutant phenotypes. We propose that an ancient mechanism for chromatin modification has been independently recruited to different developmental processes in the two kingdoms.

Arabidopsis↗
PubMed1999

Experience with ceftazidime parenteral-to-parenteral dosage stepdown in the empiric treatment of febrile neutropenia.

We assessed the clinical and economic impact of a new parenteral-toparenteral stepdown program involving ceftazidime for the treatment of febrile neutropenia. This was a two-phase (before and after), 12-month, single-center, prospective study with a historical control. Ninety-eight ceftazidime treatment courses (47 preintervention, 51 postintervention) were administered for management of febrile neutropenia in 85 adults with hematologic malignancies. Multidisciplinary creation and promotion of parenteral-to-parenteral ceftazidime stepdown criteria were applied at the discretion of the health care team. Patient demographics between phases were similar. Only 2 (4%) treatment courses before the intervention involved parenteral-to-parenteral dosage stepdown, compared with 34 (67%) after the intervention (p<0.00001). Mean number of total ceftazidime doses/treatment course and mean duration of therapy did not change between phases. Clinical cure or improvement was identified in 74% and 80% of treatment courses before and after the intervention, respectively. The two main reasons for discontinuing the drug before the intervention were recovery of neutrophil count (60%) and adverse reactions (19%). Neutrophil count recovery (59%) and hospital discharge (14%) were the two most common reasons for discontinuation after the intervention. Of 34 stepdown treatment courses after the intervention, 3 (9%) failed to meet established stepdown criteria, and 2 of these required stepdown reversal. Ancillary antibacterial drugs and treatment course outcomes were similar between phases. Total ceftazidime acquisition cost for 704 treatment days in the preintervention phase was $52,473 CAN compared with $54,778 CAN for 907 days of therapy in the postintervention phase. The mean acquisition cost/ceftazidime treatment course was $1100 CAN and did not differ between phases. The mean daily cost of ceftazidime therapy was lower after the intervention ($60.39 vs $74.54 CAN) as a result of a greater frequency of stepdown (p<0.001). Assuming an equivalent number of treatment days, the projected annual acquisition cost avoidance associated with this stepdown program was $19,900 CAN.

Adult↗
PubMed1998

Piperacillin/tazobactam versus imipenem: a double-blind, randomized formulary feasibility study at a major teaching hospital.

With the introduction of piperacillin/tazobactam to the North American market, hospitals have been faced with the task of making a decision regarding its formulary role. In view of its broad spectrum of activity, piperacillin/tazobactam could be considered as a formulary alternative to imipenem. To evaluate the formulary feasibility of substituting piperacillin/tazobactam for imipenem, a comparative assessment of these agents in the empiric treatment of serious bacterial infections was undertaken at this tertiary care hospital. This trial was conducted as a randomized, double-blind, single-center study. Consenting adult patients (>16 years of age) who were prescribed imipenem were randomized to receive either 4 g of i.v. piperacillin/tazobactam or imipenem 500 mg of i.v. Q6H with or without concurrent antibiotics. Doses were adjusted according to renal function. There were no restrictions regarding the use of nonstudy antibiotics before and during the study period. Patients with beta-lactam allergies or meningitis or who had received greater than 72 h of previous imipenem therapy were excluded. Patients were evaluated at the end of treatment, at discharge, and at 30 days postdischarge. Endpoints included both clinical and microbiologic efficacy as well as drug toxicity. Over the 433-day study period, 360 imipenem treatment courses were initiated. Of these, 150 treatment courses (75 piperacillin/tazobactam courses and 75 imipenem courses) met study criteria and were subsequently randomized. The distribution of prescriber services for enrolled patients was similar to that for all patients receiving imipenem during the study period (p = 0.15). Also, there were no statistically significant differences in demographic parameters between enrolled and excluded patients. For those patients enrolled in the study, demographic characteristics, treatment course indication(s), and accompanying antibiotics were similar across treatment arms. The mean duration of study drug therapy was 7.7 days (SD, 6.2) for imipenem and 7.5 days (SD, 6.7)for piperacillin/tazobactam (p = 0.84). In the majority of cases, treatment discontinuation occurred as a result of a favorable treatment course outcome, stepdown to a narrower spectrum parenteral agent, or stepdown to an oral agent and did not differ between study drugs (p = 0.73). Clinical and microbiologic treatment course outcomes were also similar across treatment arms. Clinical outcome was deemed successful or improved for 68% of imipenem and 70% of the piperacillin/tazobactam treatment courses (p = 0.54). Fifty-three percent of treatment courses were microbiologically confirmed. Of the 58 courses that were assessed for microbiological outcome, 93% demonstrated successful eradication of the causative pathogens. There was no difference between study drugs (96% imipenem; 90% piperacillin/tazobactam; p = 0.61). The proportion of treatment courses with at least one adverse event was similar between the study drugs (p = 1.0). Nausea and/or vomiting were/was observed more commonly in the imipenem arm (p = 0.03). Discontinuation of therapy due to drug toxicity occurred in 16% of imipenem and 5% of piperacillin/tazobactam treatment courses (p = 0.06). There was no statistically significant difference between the mean treatment course cost for imipenem ($762; range, $55-$3192) versus piperacillin/tazobactam ($696; range, $79-$2967; p = 0.59). In summary, piperacillin/tazobactam seems to represent a suitable alternative to imipenem for several clinical indications including intraabdominal infections, pneumonia, febrile neutropenia, and skin/soft tissue infections in which the causative pathogens are susceptible. However, in view of the prevalence of multiresistant Gram-negative aerobic pathogens at this institution, we do not believe that imipenem can be removed from the drug formulary. In addition, at the currently studied dosing regimen, there seems to be no evidence of a direct cost advantage associated with

Adolescent↗
PubMed1997

Relating physical activity to health status, social connections and community facilities.

An important public health goal is to increase the population's participation in regular, moderate physical activity. Descriptive epidemiological studies that focus only on associations between physical activity and demographic and psychological factors are not sufficient to inform exercise promotion strategies, and a broader view of health is required. This study investigates the additional factors of health status, social connections and satisfaction with local area facilities by analysing data from a 1987 community health survey of 1765 residents of Adelaide. Factors associated with low activity were age group, education, general health (women), reduced mobility, number of social connections (men) and degree of satisfaction with recreation facilities. Including social and structural factors is valuable for research into interventions, policy and theory relating to physical activity as it brings theoretical perspectives and links to other areas of public health and social research.

Adolescent↗
PubMedDate not supplied

St. Jude SPV versus Medtronic Freestyle: a single institution comparison of two stentless aortic valves.

BACKGROUND: Improved hemodynamics with the SPV and Freestyle bioprostheses compared to stented valves have been reported. It has been suggested that there is more aortic insufficiency (Al) with the Freestyle than with the SPV valve. This study was designed to assess the hemodynamic performance of these two valves implanted at a single institution with all echocardiograms reviewed by one echocardiographer. METHODS: From 1993 to 1997 112 patients underwent aortic valve replacement with stentless aortic valves (69 SPV, 43 Freestyle). There were no major preoperative differences in patient age, gender, NYHA class, or ejection fraction between groups. Echocardiographic assessment was obtained at discharge, 3 to 6 months following surgery, and yearly thereafter. RESULTS: Mean follow-up was 15.9 months for the SPV and 28.6 months for the Freestyle. Both valves have excellent valve areas and low transvalvar mean gradients. There is a trend for more Al in the SPV group. At 1 year, 1+ or greater Al was present in 11 of 42 SPV patients compared to 2 of 34 Freestyle patients (p = 0.030). Al has tended to remain stable over time, has not progressed, and is not clinically evident. DISCUSSION: Differences in the previously reported incidence of aortic insufficiency with these valves may have more to do with the method of reporting Al than its actual frequency. Within our institution, there has been slightly more mild Al with the SPV valve than with Freestyle. Long-term follow-up of these valves is needed to determine if the Al progresses or becomes clinically important. To date there is no such trend with either valve.

Adult↗