PubMed Health⌕ Search

Biomedical subjects

N McKenzie

Publications and source records attributed to N McKenzie.

At least 19 recordsLinked to original sources
PubMed2006

Early outcomes of coronary artery bypass with and without cardiopulmonary bypass in octogenarians.

BACKGROUND: Off-pump coronary artery bypass (OPCAB) surgery has been successfully used in diverse patient populations and has been postulated to be safer than conventional coronary artery bypass (CCAB) surgery in some high-risk patients, including the elderly. OBJECTIVE: To compare the safety of OPCAB surgery versus CCAB surgery in the octogenarian population of two large southwestern Ontario cardiac surgical units. RESULTS: Two hundred thirty-six consecutive octogenarians underwent primary isolated coronary artery bypass surgery from November 2000 to March 2005. Patients undergoing OPCAB surgery tended to have higher Parsonnet scores, while patients undergoing CCAB surgery had a greater number of emergent operations. The Canadian Cardiovascular Network predicted that mortality risk was similar in both groups. In-hospital mortality was similar between groups, as was postoperative myocardial infarction and new onset of renal dysfunction. However, in the OPCAB group, there was a decreased incidence of postoperative neurological dysfunction (2.3% in the OPCAB group versus 10.5% in the CCAB group, P=0.01), in particular cerebrovascular accidents (1.5% in the OPCAB group versus 7.6% in the CCAB group, P=0.05), and a decreased incidence of prolonged intubation (5.3% in the OPCAB group versus 13.3% in the CCAB group, P=0.04). Multivariable analysis found that cardiopulmonary bypass had no significant impact on mortality or length of stay. CONCLUSIONS: In octogenarian patients, OPCAB surgery is as safe as CCAB surgery in terms of mortality and major morbidity. Furthermore, a significant reduction in neurological dysfunction and prolonged intubation was seen in the OPCAB group compared with the CCAB group.

Aged, 80 and over↗
PubMed1999

Quick rating of depressed mood in patients with anxiety disorders.

BACKGROUND: Regular assessment of mood is often important for treatment but traditional measures can be time-consuming. A quick'litmus test' is needed. AIMS: To test the reliability and validity of a single-item scale for mood. METHOD: Mood was measured repeatedly in 812 patients (258 in-patients, 554 out-patient) being treated in an anxiety disorders unit. Patients had self- and clinician ratings of a single-item depression scale and also rated the 21-item Beck Depression Inventory (BDI-21). Their single-item scores were compared with BDI-21 scores and with outcome measures. RESULTS: The single-item depression scores correlated 0.71 to 0.78 with the BDI-21 scores. Clinically useful cut-off points were identified. Depression scores at discharge, but not pre-treatment, correlated significantly with improvement in the main problem. CONCLUSIONS: The quick single-item depression scale, whether rated by patient or by clinician, is a reasonable rough guide to mood in anxiety disorders and saves time for the patient and the clinician compared to longer measures.

Affective Disorders, Psychotic↗
PubMed1998

Volumetric object modeling for surgical simulation.

Surgical simulation has many applications in medical education, surgical training, surgical planning and intra-operative assistance. However, extending current surface-based computer graphics methods to model phenomena such as the deformation, cutting, tearing or repairing of soft tissues poses significant challenges for real-time interactions. This paper discusses the use of volumetric methods for modeling complex anatomy and tissue interactions. New techniques are introduced that use volumetric methods for modeling soft-tissue deformation and tissue cutting at interactive rates. An initial prototype for simulating arthroscopic knee surgery is described which uses volumetric models of the knee derived from 3-D magnetic resonance imaging, visual feedback via real-time volume and polygon rendering, and haptic feedback provided by a force-feedback device.

Arthroscopy↗
PubMed1998

Randomised controlled trial of the use of a modified postal reminder card on the uptake of measles vaccination.

OBJECTIVE: To determine whether rewording postal reminder cards according to the "health belief model", a theory about preventive health behaviour, would help to improve measles vaccination rates. DESIGN: A randomised controlled trial, with blind assessment of outcome status. Parents of children due for their first measles vaccination were randomised to one of two groups, one receiving the health belief model reminder card, the other receiving the usual, neutrally worded card. The proportion of children subsequently vaccinated in each group over a five week period was ascertained from clinical (provider based) records. SETTING: A local government operated public vaccination clinic. PARTICIPANTS: Parents of 259 children due for measles vaccination. MAIN RESULTS: The proportion of children vaccinated in the health belief model card group was 79% compared with 67% of those sent the usual card (95% CI, 2% to 23%), a modest but important improvement. CONCLUSION: This study illustrates how the effectiveness of a minimal and widely practised intervention to promote vaccination compliance can be improved with negligible additional effort.

Adult↗
PubMed1997

Embolization of iliac artery aneurysms following abdominal aortic aneurysm repair with a bifurcated graft.

Six iliac artery aneurysms in four patients were percutaneously embolized. All patients had previous abdominal aortic aneurysm repair using a bifurcation graft with distal anastomoses to external iliac arteries. The iliac aneurysms involved the oversewn common iliac arteries in all patients. Embolizations were performed via an ipsilateral common femoral arterial approach, with metal coil occlusion of aneurysm inflow and outflow. All aneurysms were successfully thrombosed. Follow-up colour flow Doppler examinations showed continued aneurysm thrombosis in all patients. One patient developed post procedure buttock claudication, which improved over time; there was no other procedure related morbidity. In conclusion, we describe a technique for percutaneous embolization of iliac aneurysms following abdominal aortic aneurysm repair with a bifurcated graft. We have demonstrated the safety and efficacy of this approach.

Aged↗
PubMed1994

Effects of childhood trauma on psychological functioning in adults sexually abused as children.

Standardized symptom measures were used to determine the effect of childhood trauma experiences on adults sexually victimized as children. One hundred eighty-eight sexually abused individuals were tested for mean scores for depression, self-esteem, general levels of trauma symptoms, sexual dysfunction, posttraumatic stress disorder symptoms, and dissociation. Childhood traumatic experiences (parents fighting, physical abuse by father or by mother, other childhood traumas) of a nonsexual nature correlated with increased symptom levels and accounted for significant changes in percentage of variance ranging from 5.2% (general trauma symptoms) to 12.3% (posttraumatic stress disorder). Even after controlling for nonsexual-abuse trauma, sexual trauma in childhood continued to contribute significantly to increased adult symptom levels. Variables tested included number of perpetrators; incest; age of first abuse; whether force, bribes, or threats were used by the perpetrator; and penetration. The use of force was the single most significant individual sexual abuse variable. Sexual abuse as a whole contributed significantly to all the symptom measures with the most change in variance noted for dissociation (20.5%). Gender contributed significant differences only for sexual dysfunction when men scored significantly worse.

Adult↗
PubMed1993

A community response to the needs of drug users. Stand Up Harlem.

In our first article reporting the results of a study by Health/PAC's Drug Treatment Policy Project, "Toward a Client-Centered Understanding of Drug Treatment" (Fall 1993 issue), we discussed the general inadequacy of public drug treatment services in New York City and the myriad obstacles that exist to obtaining treatment. This article maintains the client-centered perspective in examining an alternative approach that has been successful in helping drug users.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Is lung retransplantation indicated? Report on four patients.

As more lung transplantations are performed, many patients will suffer graft failure and will be considered for retransplantation. This article reviews the case management reports of four patients who received lung or heart/lung retransplantation, with overall disappointing results. The pros and cons of lung retransplantation are discussed.

Adult↗
PubMed1991

Association of Treacher Collins syndrome and translocation 6p21.31/16p13.11: exclusion of the locus from these candidate regions.

Treacher Collins syndrome (TCS) is an autosomal dominant defect of craniofacial development which has not been chromosomally localized. We have identified a mother and two children who have TCS and also a balanced translocation t(6;16)(p21.31;p13.11), which suggested the possibility that the TCS locus might be located at one of the translocation breakpoints. These were defined by in-situ hybridization as 6p21.31 (by using loci in the HLA complex defined by the probes p45.1DP beta 003/HLA-DPB2 and pRS5.10/HLA class I chain) and 16p13.11 (by using probes pACHF1.3.2/D16S8 and VK45/D16S131). Pairwise and multipoint linkage analysis using localized chromosome 6 probes and chromosome 16 probes in 12 unrelated TCS families with multiple affected siblings excluded the TCS locus from proximity to both translocation breakpoints. These data were confirmed when a third affected child, who did not exhibit the translocation, was born to the mother.

Chromosome Banding↗
PubMed1991

Medical complications of spinal cord disease.

Spinal cord injury increases the risk of many life-threatening medical problems, including respiratory failure, pulmonary embolism, and renal failure. Respiratory failure results from paralysis of muscles of inspiration (which impairs oxygen transport to alveoli) and of expiration (which impairs cough and predisposes to pneumonia and atelectasis). Respiratory failure in patients with spinal cord injury can be prevented by proper positioning of the patient, training of ventilatory muscles, pulmonary toilet, and aggressive use of antibiotics and bronchodilators. When respiratory failure occurs, it can be managed by administration of oxygen, intubation, and mechanical ventilation, and in instances of paralysis of the diaphragm, by diaphragmatic pacing. The risk of deep vein thrombosis and pulmonary embolism in acute spinal cord disease is increased by the immobilization of the patient and abnormalities in clotting factors. Thrombotic disease in spinal cord disease can be prevented by intermittent calf compression and heparinization. If pulmonary embolism develops, the patient should be started on a regimen of warfarin for at least 3 months. If anticoagulation is contraindicated, a Greenfield filter can be placed. However, concurrent use of quad cough places the patient at increased risk for complications from the Greenfield filter. Chronic pyelonephritis and systemic amyloidosis are the most common causes of renal failure in the patient with spinal cord disease. Renal failure can be prevented by maintaining a low postvoid residual volume, avoidance of indwelling catheters, use of medications that are not nephrotoxic, and rapid treatment of infection. Hemodialysis and peritoneal dialysis can extend the life of the patient with spinal cord disease in whom renal failure develops, and successful use of renal transplantation has recently been reported.

Humans↗
PubMed1988

Increased protein synthesis response to insulin in fibroblasts treated with the diacylglycerol kinase inhibitor R59022.

Insulin stimulated protein synthesis in quiescent 3T3 fibroblasts. This effect of the hormone was greater in the presence of the diacylglycerol kinase inhibitor R59022 (10(-5) M) over a range of insulin concentrations from 1 microU to 1 mU/ml; R59022 increased the sensitivity of cells to insulin. The amount of radioactive diacylglycerol recovered from cells prelabelled with [3H]glycerol was increased transiently in response to insulin; the response was larger and prolonged in cells given the kinase inhibitor. The results (i) support the hypothesis that diacylglycerol production is part of the signal pathway by which insulin stimulates protein synthesis and (ii) suggest that inhibition of diacylglycerol breakdown leads to increased sensitivity to the hormone.

Animals↗
PubMed1988

The effects of dietary fat content on the growth and body composition of lean and genetically obese Zucker rats adrenalectomized before weaning.

1. Lean (Fa/-) and obese (fa/fa) Zucker rats were adrenalectomized or sham-operated at 18 d of age (3 d before weaning). After weaning the rats were fed ad lib. on semi-synthetic diets containing either a low (8 g/kg) or a high (178 g/kg) proportion of fat. Other groups of sham-operated rats were given the same amount eaten by adrenalectomized animals (restricted intake). Rats were killed at 40 d of age. 2. Adrenalectomy reduced the body lipid content of lean and obese rats compared with intact animals fed ad lib. or given a restricted intake. Adrenalectomized obese rats contained more body lipid than intact or adrenalectomized lean rats. 3. Sham-operated obese rats given a restricted intake had less body protein than similarly treated lean animals and this phenotypic difference was abolished by adrenalectomy. 4. There were no effects of diet on growth or body composition of intact or adrenalectomized rats. 5. It is concluded that preweaning adrenalectomy prevented development of the obese phenotype when rats were fed on either diet. Comparison of these results with a previous study, in which adrenalectomized Zucker rats were fed on a stock diet (Fletcher, 1986b), showed, however, that feeding either of the semi-synthetic diets caused greater deposition of body lipid in obese rats.

Adrenalectomy↗
PubMed1988

The parasympathetic nervous system and glucocorticoid-mediated hyperinsulinaemia in the genetically obese (fa/fa) Zucker rat.

Lean (Fa/-) and genetically obese (fa/fa) Zucker rats were adrenalectomized at 18 days of age (3 days before weaning) before the onset of hyperinsulinaemia. At 40-41 days of age, basal and glucose-stimulated insulin concentrations did not differ significantly between lean and obese rats. Plasma insulin and glucose concentrations were higher in both phenotypes 24 h after administration of corticosterone (2.0 mg at 12-h intervals). Corticosterone-treated obese rats had higher basal and glucose-stimulated insulin levels than similarly treated lean animals, although plasma glucose concentrations did not differ between phenotypes. The basal plasma insulin concentration of obese rats treated with corticosterone for 24 h was reduced 15, 30 and 45 min after injection of atropine (0.3 mg) without any significant change in the plasma glucose level. Injection of atropine (0.3 mg) 20 min before a glucose load prevented the greater increment in plasma insulin concentration of corticosterone-treated obese rats compared with similarly treated lean animals. Atropine administration (0.3 mg) to intact obese rats at 40 days of age reduced, but did not abolish, their hyperinsulinaemia compared with intact lean animals. It is concluded that (1) pre-weaning adrenalectomy prevents the development of hyperinsulinaemia in genetically obese rats, (2) corticosterone replacement for only 24 h restores the hyperinsulinaemia of obese rats, (3) the differential effects of corticosterone on insulin secretion by lean and obese rats are mediated by the parasympathetic nervous system and (4) the parasympathetic nervous system contributes to, but is not the only cause of, hyperinsulinaemia in intact obese rats.

Adrenalectomy↗