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Biomedical subjects

W Brett

Publications and source records attributed to W Brett.

At least 19 recordsLinked to original sources
PubMed2005

Selection bias of elderly patients with chronic angina referred for catheterization.

BACKGROUND: Registry patients are generally older and more sick than patients enrolled in trials questioning the generalizability of trial results. We assessed whether such a selection bias also exists in elderly patients with chronic angina referred for catheterization. METHODS AND RESULTS: All 119 patients age>or=75 years with Trial of Invasive versus Medical Therapy in the Elderly (TIME) inclusion but no major exclusion criteria referred for catheterization during the TIME trial inclusion period in four TIME centers were registered and followed-up for one year. Registry patients differed from the 188 trial patients in the same hospitals in that they were younger, somewhat more frequently male, with less antianginal drugs and studied more often after acute chest pain at rest but with more comorbidities than study patients. Left ventricular ejection fraction and vessel disease were similar. One year mortality was 11.4% in registry and 9.6% in invasive TIME patients but differences disappeared after adjustment for baseline differences. Symptomatic status after one year was similar too. CONCLUSIONS: In elderly patients with chronic angina, a bias in the selection for invasive management exists which seems different from that reported in younger patient settings. After adjustment for these selection factors, however, one-year outcome was remarkably similar in registry and trial patients.

Aged↗
PubMed2003

Use of myocardial tissue Doppler imaging for intraoperative monitoring of left ventricular function.

BACKGROUND: Detection of myocardial ischaemia during surgery is usually by assessment of regional wall motion using two-dimensional transoesophageal echocardiography (TOE). Tissue Doppler imaging (TDI) may assist this assessment and improve its accuracy. METHODS: We measured peak myocardial velocities in the anterior mid-wall of the left ventricle by TOE and pulsed-wave TDI in addition to transmitral flow velocity, two-dimensional echocardiography and cardiovascular variables. We studied 42 patients before and after coronary bypass surgery with left internal mammary artery grafts. RESULTS: Peak systolic and early and late diastolic velocity measurements of the anterior mid-wall were obtained in all patients. Variation between and within observers was small (<6%). Peak systolic thickening velocity correlated with visual assessment of anterior wall motion score, fractional area change of the left ventricle and left ventricular systolic wall stress. Because of the wide overlap of systolic velocity between the segments with normal and abnormal wall motion, it was not possible to separate normal from abnormal segments on the basis of TDI-derived velocity alone. The diastolic velocity in the anterior wall reflected the transmitral filling pattern. After surgery, the peak systolic and late diastolic anterior wall velocities increased (from 4.2 (95% confidence interval 4.0, 4.7) to 5.7 (4.8, 6.3) cm s(-1) and from 3.5 (3.2, 3.9) to 6.0 (5.1, 6.9) cm s(-1) respectively), while the ratio of early to late diastolic velocity decreased from 1.5 (1.2, 1.7) to 1.0 (0.8, 1.2). TDI changes characteristic of new myocardial ischaemia were not seen in any patient. CONCLUSION: Intraoperative measurement of TDI in the anterior wall of the left ventricle is feasible and provides additional quantitative information on both regional and global systolic and diastolic function. We found changes in myocardial velocities indicating improvement in the systolic and impairment in the diastolic function of the anterior wall of the left ventricle immediately after mammary artery grafting.

Aged↗
PubMed2001

Translocation of S100A1(1) calcium binding protein during heart surgery.

Myocardial ischemia during cardiopulmonary bypass terminated by reperfusion generally leads to different degrees of damage of the cardiomyocytes induced by transient cytosolic Ca(2+) overload. Recently, much attention has been paid to the role of heart-specific Ca(2+)-binding proteins in the pathogenesis of myocardial ischemia-reperfusion injury. S100A1 is a heart-specific EF-hand Ca(2+)-binding protein that is directly involved in a variety of Ca(2+)-mediated functions in myocytes. The aim of our study was to investigate the localization and translocation of S100A1 in the human heart under normal (baseline) conditions and after prolonged ischemia and reperfusion of the myocardium. Our data suggest that S100A1 is directly involved in the transient perioperative myocardial damage caused by ischemia during open heart surgery in humans. Given its role in the contractile function of muscle cells, this S100 protein could be an important "intracellular link" in ischemia-reperfusion injury of the heart.

Calcium-Binding Proteins↗
PubMed2000

The mechanism of cryoinjury: In vitro studies on human internal mammary arteries.

The mechanism of cryoinjury was investigated in human internal mammary arteries (IMA) by monitoring contractile responses to ET-1 and KCl. For cryopreservation segments of IMA were equilibrated for 20 min with the cryomedium (RPMI 1640 culture medium containing 1.8 M DMSO and 0.1 M sucrose), frozen at a mean cooling rate of 1.3 degrees C min(-1) to -70 degrees C and stored in liquid nitrogen. Before use, samples were thawed slowly and the cryomedium removed by dilution. Compared to unfrozen controls, ET-1 stimulated frozen/thawed IMA with similar efficacy but at 3 fold lower concentrations (P<0.001). Addition of ET-1 (100 nM) induced maximal contraction of unfrozen IMA within 10 min, declining thereafter to 25% after 90 min. In frozen/thawed IMA the ET-1-induced contraction was sustained but could be reversed if protein kinase C was blocked by staurosporine (100 nM). Responses to ET-1 of cryostored IMA were 5 fold more susceptible to blockade by nifedipine than those of controls. After cryostorage the efficacy of KCl was diminished to 40% (P<0.05) and the KCl curve was shifted to the left (2 fold, P<0. 001). In both unfrozen and cryostored IMA the KCl (60 mM) effect was sustained and equally susceptible to nifedipine. It is suggested that the smooth muscle cell of IMA is receptive to physical forces which occur during cryopreservation. These forces modify transmembrane signal transduction and intracellular pathways, that are common to pharmacological agonists thereby changing vascular responses to several contractile agonists after thawing.

Calcium↗
PubMed1999

Antibiotic susceptibility of Streptococcus pneumoniae in New Zealand.

AIMS: To determine the current antibiotic susceptibility patterns of Streptococcus pneumoniae from four centres in New Zealand. METHODS: Over a six-month period in 1997, 386 consecutive clinical isolates of S pneumoniae were collected by four laboratories (Auckland, Wellington, Hamilton and Christchurch) from general practice or inpatients. Susceptibility testing for seven antibiotics was performed by each centre using the Etest. RESULTS: Eighty-three-percent of isolates were penicillin susceptible, 12% showed intermediate resistance to penicillin and 5% were penicillin resistant. Overall, 93 and 91% of isolates were susceptible to amoxicillin/clavulanic acid and ceftriaxone, respectively. Erythromycin and tetracycline had similar rates of susceptibility (88 and 87%, respectively). Resistance to cotrimoxazole was common, with only 57% of isolates susceptible to this combination. No National Committee for Clinical Laboratory Standard (NCCLS) breakpoints were available for cefaclor to allow interpretation of the minimum inhibitory concentration data for this agent. Wellington had lower resistance rates than Auckland, Christchurch and Hamilton. Isolates from children had consistently higher resistance rates (two- to five-fold greater for beta-lactams and 1.2 to 1.3-fold for other agents) compared with isolates from adult patients. CONCLUSIONS: Resistance to multiple antibiotics among S pneumoniae is now evident in New Zealand, although rates varied between study centres. The overall rate of penicillin resistance is 5%, which is similar to that observed in many European and US cities but lower than the rates reported in badly affected areas (> 30%). These data suggest that amoxicillin (+/- clavulanic acid), erythromycin or tetracycline are appropriate agents for empirical use in less serious community acquired infections when S pneumoniae is suspected. Ceftriaxone, with or without vancomycin, should be considered in the empirical treatment of invasive, disease until sensitivities are known.

Adult↗
PubMed1998

Dobutamine stress echocardiography to detect inducible demand ischemia in anesthetized patients with coronary artery disease.

BACKGROUND: A cardiac risk stratification test that can be performed during operation would be expected to give valuable information for the therapeutic management of patients who need urgent noncardiac surgery. This study was designed to evaluate the feasibility and safety of a dobutamine-atropine stress protocol to detect inducible demand ischemia in anesthetized patients. METHODS: A standard dobutamine-atropine stress protocol was performed in 80 patients with severe coronary artery disease during fentanyl-isoflurane anesthesia. Biplane transesophageal echocardiography and 12-lead electrocardiography were used to detect induced ischemia. After dobutamine testing, esmolol, nitroglycerin, or both were used to revert ischemia and any hemodynamic changes, as appropriate. RESULTS: The protocol detected inducible ischemia or achieved the target heart rate in 75 of the 80 (94%) patients. None of the prospectively defined adverse outcomes, such as cardiovascular collapse, severe ventricular arrhythmia, persistent (> or =5 min) ischemia, or hemodynamic instability, occurred in any of the patients. Ischemia was induced and detected in 73 of the 80 (91%) patients. CONCLUSION: Dobutamine stress echocardiography is feasible in anesthetized patients with severe coronary artery disease. The lack of serious complications and the high sensitivity to detect inducible ischemia in this patient population provide the basis for further evaluation of the safety and diagnostic value of dobutamine stress echocardiography during general anesthesia in larger studies of patients at risk for coronary artery disease undergoing noncardiac surgery.

Anesthesia, General↗
PubMed1996

Ularitide: from renal natriuretic peptide to clinical trials.

Ularitide is a member of the natriuretic peptide family which is presumably synthesized in the kidney. In physiological experiments a correlation between Ularitide excretion and natriuresis has been found. Ularitide infusions and bolus injections in animals initiated profound diuresis and natriuresis as the most prominent effects. On the basis of findings in in-vitro and in-vivo experiments, Ularitide was used in clinical trials, and the results indicate that it could be a promising new drug to prevent and treat acute renal failure in patients after cardiac surgery and organ transplantation.

Acute Kidney Injury↗
PubMed1993

Myocardial preservation using HTK solution for heart transplantation. A multicenter study.

Bretschneider HTK solution is commonly used for myocardial preservation. In order to evaluate its protective effect for heart transplantation, a retrospective study was initiated in cooperation with Eurotransplant and five heart transplant centers. Seventy-six female and 524 male patients who underwent cardiac transplantations between 1981 and 1991 were included in this study. Using standardized questionnaires, donor and recipient laboratory data, immunosuppressive therapy and the preoperative, intraoperative and postoperative organ function were documented. The average ischemic time of the donor hearts was 160 min, ranging from 75 min-304 min. Immediate postoperative graft failure was observed in 25 transplantations (4.2%). Within the first 30 days 71 organs (11.8%) failed. Using the chi2-test, a statistically significant increase of acute graft failure and early mortality was evident when they were correlated with the length of ischemic time (P = 0.01). In addition, a higher incidence of early graft failure was observed when the perfusion volume was less than 1500 ml. The 1- and 5-year survival rates were 72% and 63%, respectively. Organ preservation with HTK shows good results as long as the ischemic time does not exceed 4 h. The possibility that an increased perfusion volume allows longer ischemic times cannot be excluded with this study.

Cardioplegic Solutions↗
PubMed1992

Outcome and management of crisis pregnancy counselling.

Between October 1989 and April 1991, 215 women were seen in the pregnancy centre. Of these women, 139 were in crisis pregnancy situations. Of the remaining 76 women, 42 attended for pregnancy education, 10 for counselling regarding adoption options, eight for postabortion counselling, and 10 for other reasons. All 139 women in crisis pregnancy situations received counselling and assistance with the resolution of the specific life crises that the pregnancy precipitated and were informed about the physical and emotional effects of pregnancy, normal fetal development, and the options that were available to them. These 139 women were divided into three groups at the start of their initial interview, according to whether they planned to continue with the pregnancy (18), seek termination of pregnancy (72), or were ambivalent (49). The outcome for each of these groups has been evaluated separately. Overall 65 (47%) of the women changed an initial decision or reached their final decision regarding the future of their pregnancy during the time of counselling, and 64 (46%) ultimately continued with their pregnancies. These outcomes support the need for a specific approach to crisis pregnancy situations such as that provided at the pregnancy centre and provide support for considering the crisis pregnancy an obstetric emergency.

Abortion, Induced↗
PubMed1986

Tuberculosis at Green Lane Hospital 1980-1982.

An audit of tuberculosis management at Green Lane Hospital was undertaken by review of the case records of 235 cases of adult tuberculosis. There were 135 men and 100 women (mean age 47 years). Important findings include the large proportion of nonEuropeans (66%) and the frequency of drug resistance. Drug resistance was present in 29% of isolates from nonEuropean immigrants who had resided in New Zealand for a year or less. The adequacy of current medical screening of Pacific Island and South-east Asian visitors and immigrants is discussed in the context of these findings. Treatment regimens used were in accordance with accepted recommendations, although the duration (14 months in uncomplicated disease) was longer than is now thought necessary. Of the 205 patients who completed treatment under our care 186 (91%) were cured, 14 (6.8%) died, 3 (1.5%) relapsed and two defaulted. The median in hospital stay was 32 days and together with the somewhat high relapse rate (1.5%) reflects the absence of facilities for closely supervised outpatient tuberculosis treatment in Auckland.

Adolescent↗
PubMed1985

Complement in acute leukaemia: its role in infection.

This study determines the frequency of complement system dysfunction in adult patients with acute myeloid leukaemia and its prognostic significance. Twenty four patients with acute leukaemia had complement studies performed at time of presentation and during the haematological trough occurring between 7 and 14 days after the administration of chemotherapy. At presentation 32% of patients had abnormal complement function. Only 54% of patients maintained normal complement activity throughout the period of remission induction. The aetiology of the disturbance is unclear and no single causative factor was determined. Patients with abnormal complement function had significantly greater morbidity from infection during the period of remission induction as measured by the number of febrile (greater than 38 degrees C) days (p less than 0.05), and were more likely to have pathogens isolated by blood culture during septic episodes (relative risk 4.0, p less than 0.01). These findings show a significant increase in morbidity associated with depressed complement function and emphasise the important role the complement system plays in maintenance of host defences.

Adult↗
PubMed1985

Progression of hypertrophic cardiomyopathy to congestive cardiomyopathy: case report.

A case of hypertrophic cardiomyopathy presenting with chest pain and dyspnoea was followed for 18 years. During this time the patient showed a progressive loss of cardiac murmurs and over the last 12 months of life developed a dilatated cardiomyopathy associated with congestive heart failure, supraventricular and ventricular tachyarrhythmias.

Adult↗