PubMed Health⌕ Search

Biomedical subjects

J Byrne

Publications and source records attributed to J Byrne.

At least 19 recordsLinked to original sources
PubMed2006

Findings from aCGH in patients with congenital diaphragmatic hernia (CDH): a possible locus for Fryns syndrome.

Congenital diaphragmatic hernia (CDH) is a common and often devastating birth defect that can occur in isolation or as part of a malformation complex. Considerable progress is being made in the identification of genetic causes of CDH. We applied array-based comparative genomic hybridization (aCGH) of approximately 1Mb resolution to 29 CDH patients with prior normal karyotypes who had been recruited into our multi-site study. One patient, clinically diagnosed with Fryns syndrome, demonstrated a de novo 5Mb deletion at chromosome region 1q41-q42.12 that was confirmed by FISH. Given prior reports of CDH in association with cytogenetic abnormalities in this region, we propose that this represents a locus for Fryns syndrome, a Fryns syndrome phenocopy, or CDH.

Abnormalities, Multiple↗
PubMed2006

Current and future water issues in the Oldman River Basin of Alberta, Canada.

Long-term trends in alpine and prairie snow pack accumulation and melt are affecting streamflow within the Oldman River Basin in southern Alberta, Canada. Unchecked rural and urban development also has contributed to changes in water quality, including enhanced microbial populations and increased waterborne pathogen occurrence. In this study we look at changing environment within the Oldman River Basin and its impact on water quality and quantity. The cumulative effects include a decline in net water supplies, and declining quality resulting in increased risk of disease. Our data indicates that decreases in the rate of flow of water can result in sedimentation of bacterial contaminants within the water column. Water for ecosystems, urban consumption, recreation and distribution through irrigation is often drawn from waterholding facilities such as dams and weirs, and concern must be expressed over the potential for contaminate build-up and disproportionate potential of these structures to pose a risk to human and animal health. With disruption of natural flow rates for water resulting from environmental change such as global warming and/or human intervention, increased attention needs to be paid to use of best management practices to protect source water supplies.

Alberta↗
PubMed2005

Use of in-stream reservoirs to reduce bacterial contamination of rural watersheds.

An investigation into bacterial water quality problems was conducted on an interconnected stream and irrigation system within the Oldman River Basin of southern Alberta, Canada. Levels of indicator bacteria, including fecal coliforms, generic Escherichia coli and fecal streptococci, were repeatedly measured in streams and irrigation return canals of this river basin during the summer of 2001. Bacterial-loading segments of the irrigation/stream system were identified through a comparison of indicator bacteria levels in pairs of upstream and downstream sites. Mann-Whitney U-tests indicated that reservoirs significantly reduced bacterial counts. A temporal comparison of E. coli counts and river discharges suggested that these indicator bacteria do not originate from within in-stream sediments. Site-specific as well as cumulative inputs from a variety of non-point sources are likely to be responsible for the high downstream levels of indicator bacteria in this water system. The use of management practices such as in-stream reservoirs may significantly reduce contamination, and increase the quality of limited rural water supplies to allow their reuse and safe discharge into downstream water sources. The identification of bacteria-loading river/canal segments could also be used to prioritize restoration projects.

Agriculture↗
PubMed2005

Thoracofemoral bypass using spliced femoral vein with removal of an infected axillobifemoral bypass graft.

A 63-year-old male underwent emergency repair of a ruptured juxtarenal aortic aneurysm via a transabdominal approach using an aorto-bi-iliac Dacron graft. This became infected. A right axillobifemoral bypass was placed and the infected graft was removed with oversewing of the aorta. The patient was re-admitted 8 months later with an infected axillobifemoral prosthesis. We harvested both femoral veins (FV) and spliced them to perform a left thoracobifemoral bypass with simultaneous explantation of the infected graft. The patient remains well with a patent graft 20 months post-operatively.

Aortic Aneurysm, Abdominal↗
PubMed2005

Endovascular embolization of a traumatic arteriovenous fistula of the superficial temporal artery.

Arteriovenous fistula of the superficial temporal artery is a rare condition most commonly caused by trauma. Traditional surgical treatment has been superseded by endovascular embolization. We present the case of a 40 year-old man with a traumatic arteriovenous fistula of the superficial temporal artery who was treated by endovascular embolization. The advantages of this approach are discussed, along with a brief history of the condition.

Adult↗
PubMed2004

A generalized extension to the Hounsell-Wilkinson head scatter model.

Hounsell and Wilkinson (1997 Phys. Med. Biol. 42 1737-49) have demonstrated that the concept of a scatter-plane source can accurately describe head scatter in irregularly shaped fields produced by the MLC of an Elekta linear accelerator. In these linacs, the solid jaw is below the MLC set and plays no part on defining the view of the main source of head scatter, the flattening filter. A more complicated situation arises for linear accelerator head designs which incorporate a solid upper jaw pair with the MLC jaws further from the source. Application of the Hounsell and Wilkinson technique to these accelerator designs does not achieve the accuracy in the Elekta application. We present a generalized extension to Hounsell and Wilkinson's model and present results for typical treatment field shapes on a Siemens Primus linear accelerator.

Biophysical Phenomena↗
PubMed2004

Delirium.

Delirium is a common cause of mortality and morbidity in older people in hospital, and indicates severe illness in younger patients. Identification of risk factors, education of professional carers, and a systematic approach to management can improve the outcome of the syndrome. Physicians should be aware that delirium sufferers often have an awareness of their experience, which may be belied by their varying grasp of reality.

Aging↗
PubMed2003

Response to imatinib in patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia.

We studied 128 patients with chronic myeloid leukemia (CML) relapsing after allogeneic stem cell transplantation (SCT). Disease at the time of treatment with Imatinib was in chronic phase (CP) in 51 patients, accelerated phase (AP) in 31 and blastic crisis (BC) in 46. Of the 51 patients in CP, 14 were in cytogenetic and two in molecular relapses. The median interval between relapse and Imatinib therapy was 5 months (0-65). A total of 50 patients had failed treatment with donor lymphocyte infusions prior to Imatinib. The overall hemato-logical response rate was 84% (98% for patients relapsing in CP). The complete cytogenetic response (CCR) was 58% for patients in CP, 48% for AP and 22% for patients in BC. Complete molecular responses were obtained in 25 patients (26%), of whom 21 were in CP or AP. With a median follow-up of 9 months, the estimated 2-year survival for CP, AP and BC patients was 100, 86 and 12%, respectively. Out of 79 evaluable patients, 45 (57%) achieved full donor and 11 (14%) mixed chimerism after Imatinib. We conclude that Imatinib has significant activity against CML in relapse after allogeneic SCT. Durable cytogenetic and molecular remissions are obtainable in patients in CP.

Adult↗
PubMed2003

Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern Alberta and its relation to manure sources.

The Oldman River watershed in southern Alberta, Canada, is an extensively irrigated region in which intensive agricultural practices have flourished. Concern over water quality in the basin has been expressed because of high levels of enteric disease indigenous to the region. To address these concerns, we conducted a 2-year study to estimate the prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface water within the basin. This study is the first of its kind to identify E. coli O157:H7 repeatedly in surface water collected from a Canadian watershed. Prevalence of E. coli O157:H7 and Salmonella spp. in water samples was 0.9% (n = 1,483) and 6.2% (n = 1,429), respectively. While data examined at a regional level show a relationship between high livestock density and high pathogen levels in southern Alberta, statistical analysis of point source data indicates that predicted manure output from bovine, swine, and poultry feeding operations was not directly associated with either Salmonella spp. or E. coli O157:H7 prevalence. However, geography and weather variables, which are likely to influence bacterial runoff, were not considered in this model. We also postulate that variations in time, amount, and frequency of manure application onto agricultural lands may have influenced levels of surface-water contamination with these bacterial pathogens.

Alberta↗
PubMed2002

A comparison of physiological responses and rating of perceived exertion in two modes of aerobic exercise in men and women over 50 years of age.

OBJECTIVES: To compare the physiological responses and ratings of perceived exertion to aerobic dance and walking sessions completed at a self selected pace. METHODS: Six women and six men with a sample mean (SD) age of 68 (7) years completed aerobic dance and walking sessions in random order. A treadmill test was performed by each subject from which peak oxygen uptake (.VO(2)) and maximum heart rates (HRmax) were determined. During the aerobic dance and walking sessions, heart rate and .VO(2) were measured continuously throughout. Rate of perceived exertion (RPE) was measured every three minutes throughout the session. RESULTS: The sample means (SD) for %peak .VO(2) were 67 (17)% for the aerobic dance sessions and 52 (10)% for the walking sessions, and the %HRmax sample means (SD) were 74 (12)% for the aerobic dance sessions and 60(8)% for walking sessions. The sample mean (SD) RPE for the aerobic dance sessions was 11(2), and for the walking sessions it was 10(2). CONCLUSIONS: %peak .VO(2), %HRmax, and RPE were significantly higher for aerobic dance than for walking. However, both the aerobic dance and walking sessions were of adequate intensity to improve aerobic fitness in most subjects. Further investigation into the relation between RPE and %peak .VO(2) in a field setting over representative exercise time periods would be useful.

Aged↗
PubMed2002

An audit of activity and outcome from a daily and a weekly "one stop" rapid assessment chest pain clinic.

OBJECTIVES: The recent National Service Framework for coronary heart disease advocates the establishment of rapid assessment clinics for chest pain. But how should these clinics be organised and do they fulfil their objectives? The aim of this study was to compare referral patterns to a daily and a weekly "one stop" rapid access chest pain clinic (RACPC), and to examine clinical outcome in patients attending these clinics. DESIGN: Patients were prospectively categorised into one of the following subgroups: "acute coronary syndrome", "stable coronary heart disease", or "low risk/non-coronary chest pain". Fatal and non-fatal outcomes were audited over eight months. SETTING: Both RACPCs were situated within the cardiology departments of two large Glasgow teaching hospitals. Patients were seen by a cardiologist, and underwent non-invasive testing. PARTICIPANTS: A total of 633 patients with chest pain who were referred by their general practitioner; 500 came to the daily and 133 to the weekly clinic. Forty four (7%) were categorised as having an acute coronary syndrome, 267 (42%) as stable coronary artery disease, and 322 (51%) as low risk/non-coronary chest pain. RESULTS: Referral patterns to the two clinics differed significantly. Compared with the weekly clinic, more patients with an acute coronary syndrome (7.8 v. 3.8%) and low risk/non-coronary chest pain (55.2 v. 35.6%), but fewer patients with stable coronary disease (37.0 v. 61.6%) were referred to the daily clinic (p<0.00001). During follow up eight (1.3%) patients died from a cardiac cause, and eight (1.3%) patients suffered a myocardial infarction. None of these patients were classified as low risk/non-coronary chest pain. CONCLUSIONS: (1) RACPCs do provide an effective tool for the early assessment of patients with possible angina. (2) The frequency with which clinics are scheduled may be an important factor in determining how the service is utilised in practice.

Aged↗
PubMed2001

Aneurysmal SAH: cognitive outcome and structural damage after clipping or coiling.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (SAH) and surgical clipping of intracranial aneurysms are associated with substantial morbidity and mortality. OBJECTIVE: To compare cognitive outcome and structural damage in patients with aneurysmal SAH treated with surgical clipping or endovascular coiling. METHODS: Forty case-matched pairs of patients with aneurysmal SAH treated by surgical clipping or endovascular coiling were prospectively assessed by use of a battery of cognitive tests. Twenty-three case-matched pairs underwent MRI 1 year after the procedure. Matching was based on grade of SAH on admission, location of aneurysm, age, and premorbid IQ. RESULTS: Both groups were impaired in all cognitive domains when compared with age-matched healthy control subjects. Comparison of cognitive outcome between the two groups indicated an overall trend toward a poorer cognitive outcome in the surgical group, which achieved significance in four tests. MRI showed focal encephalomalacia exclusively in the surgical group. This group also had a significantly higher incidence of single or multiple small infarcts within the vascular territory of the aneurysm, but both groups had similar incidence of large infarcts and global ischemic damage. CONCLUSION: Endovascular treatment may cause less structural brain damage than surgery and have a more favorable cognitive outcome. However, cognitive outcome appears to be dictated primarily by the complications of SAH.

Cognition↗
PubMed2001

Harm reduction - a historical view from the left.

The harm reduction movement formed during a period in which social movements of the working class and the excluded were weak, neo-liberalism ideologically triumphant, and potential opposition movements were viewed as offering "tinkering" with the system rather than a total social alternative. This climate shaped and limited the perspectives, strategies, and tactics of harm reductionists almost everywhere. In many countries, this period was also marked by a "political economy of scapegoating" that often targeted drug users as the cause of social woes. This scapegoating took the form of "divide and rule" political initiatives by business and political leaderships to prevent social unrest in a long period of worldwide economic trends toward lowered profit rates and toward increasing income inequality. However, times have changed. Mass strikes and other labor struggles, opposition to the World Trade Organisation and other agencies of neo-liberalism, community-based protests against belt-tightening, and other forms of social unrest have been increasing in many countries. This opens up the possibility of new allies for the harm reduction movement, but also poses difficult problems for which we need to develop answers. On-the-ground experience in alliance formation needs to be combined with careful discussion of and research about what approaches work to convince other movements to work for and with harm reduction, and which approaches do not. Class differences within the harm reduction movement are likely to become more salient in terms of (a) creating internal tensions, (b) increasingly, opening up new ways in which working class harm reductionists can organize within their own communities and workplaces, and (c) producing different strategic orientations that will need to be discussed and debated. As a movement, we will need to find ways to accommodate and discuss differing perspectives, needs, and assessments of opportunities and threats without paralyzing harm reduction activities.

Journal Article↗
PubMed2001

Prognosis of patients turned down for conventional abdominal aortic aneurysm repair in the endovascular and sonographic era: Szilagyi revisited?

PURPOSE: The United Kingdom Small Aneurysm study has demonstrated the low risk of rupture in aneurysms less than 5.5 cm in diameter. With the advent of endoluminal techniques, patients considered unfit to undergo laparotomy are now considered for endovascular repair. However, the natural history of aneurysms larger than 5.5 cm remains uncertain, especially when severe comorbidity is present. In our center, we prospectively maintain records of all patients for whom elective aneurysm surgery was refused. This study documented the outcome of all patients referred with abdominal aortic aneurysms (AAAs) larger than 5.5 cm in diameter who were turned down for elective open repair and determined the cause of death and risk of rupture in all patients. METHODS: Details of all patients with AAAs from January 5, 1989, to January 5, 1999, were recorded, and demographic details on all patients with AAAs larger than 5.5 cm were collected. Copies of death certificates were obtained from the Office of National Statistics, local in-hospital patient records, and general practitioner records. Results of postmortem examinations were also obtained. Aneurysms were stratified according to their size at presentation (5.5-5.9 cm, 6.0-7.0 cm, and > 7.0 cm), and the reasons no intervention was made were documented. RESULTS: A total of 106 patients were turned down for elective aneurysm surgery in the 10-year period (10.6 per year). The mean age of the patients was 78.4 years (SD, 7.4), and 70 were men and 36 were women. At the end of the study, 76 patients (71.7%) had died. Overall, the 3-year survival rate was 17%. Patients with AAAs larger than 7.0 cm lived a median of 9 months. A ruptured aneurysm was certified as a cause of death in 36% of the patients with an AAA of 5.5 to 5.9 cm, in 50% of the patients with an AAA of 6 to 7.0 cm, and 55% of the patients with an AAA larger than 7.0 cm. Reasons given for not intervening were patient refusal (31 cases), the patient being "unfit for surgery" (18 cases), the "advanced age" of the patient (18 cases), cardiac disease (9 cases), cancer (9 cases), respiratory disease (6 cases), and other (15 cases). CONCLUSION: Although we recognize the problems with death certification, we found that rupture was a significant cause of death in patients with an untreated AAA that was larger than 5.5 cm. Although little difference in outcome was observed in aneurysms in the 5.5 to 7.0 cm size range, patients with an AAA that was larger than 7.0 cm seemed to have a much poorer prognosis.

Aged↗
PubMed2001

Allogeneic stem-cell transplantation for lymphoproliferative disorders using BEAM-CAMPATH (+/- fludarabine) conditioning combined with post-transplant donor-lymphocyte infusion.

BACKGROUND: We report our updated experience of allogeneic transplantation in lympho-proliferative disorders using a reduced-intensity conditioning regimen combining BEAM (plus fludarabine in three cases) with pre-transplant CAMPATH. Post-transplant donor lymphocytes have been infused for persisting disease or relapse, and both chimerism and minimal residual disease have been monitored utilizing molecular techniques. METHODS: Thirty patients with median age 47.6 years underwent allogeneic transplantation for relapsed or high-risk lymphoproliferative disease using HLA-identical (sibling n = 25, unrelated n = 2) or one antigen mismatched sibling donors (n = 3). Twenty-one had NHL, three had HD and six had CLL/PLL. Stem-cell source was PBSC (n = 24), BM (n = 5) or both (n = 1) with a median CD34 dose of 4.5 x 10(6)/kg. GvHD prophylaxis was with CYA and MTX. RESULTS: Engraftment was prompt in the majority of patients, with a median of 15 days to both ANC > 0.5 and platelets > 20. There have been three transplant-related deaths secondary to viral pneumonitis or bacterial pneumonia. Seven patients developed Grade I-II acute GvHD post-transplant. Of 28 evaluable patients, 18 achieved a CR at assessment 2-3 months post-transplant and a further patient converted from PR to CR following DLI, to give an overall CR rate of 68%. Three patients had early progressive disease and six have relapsed from CR or progressed from PR (two of whom have achieved CR following DLI therapy). Overall survival is 67% and event-free survival 48% at 3 years. With a median follow-up of 1.3 years 57% of patients are currently alive and lymphoma-free. A molecular remission has been achieved in nine of 12 informative patients. DISCUSSION: These encouraging results show that this reduced-intensity conditioning regimen is effective, with a low-toxicity profile compared with conventional TBI-based conditioning, and certainly merits further evaluation in this setting.

Adolescent↗
PubMed2001

Treatment of intractable angina in a nonagenarian patient by direct coronary stenting.

BACKGROUND: A 91-year-old man presented with a 6-month history of exertional angina. As he was already on maximally tolerated medical therapy, we decided to perform coronary angiography, which revealed severe stenosis of the distal main stem coronary artery, OUTCOME: The lesion was crossed with an intra-coronary wire, and a stent placed to cover the distal main stem lesion, without prior balloon dilatation. The result was satisfactory and he remains symptom-free at 6-month follow-up. CONCLUSION: Treatment of left main stem lesions with percutaneous intervention may be an acceptable alternative to surgery in high-risk elderly patients. Since percutaneous coronary angioplasty can be performed on very elderly patients with a high degree of success, the decision to investigate and treat should not be based solely on biological age.

Aged↗