PubMed Health⌕ Search

Biomedical subjects

R J Holdsworth

Publications and source records attributed to R J Holdsworth.

At least 19 recordsLinked to original sources
PubMed2004

Near-infrared tunable diode laser spectrometer for the remote sensing of vehicle emissions.

A near-infrared diode laser-based spectrometer has been designed and built for the remote sensing of vehicle emissions. It detects carbon monoxide and carbon dioxide absorptions around 1580 nm and can provide the ratio CO/CO(2) for vehicle exhaust studies. The system is battery powered and is designed to sit unobtrusively at the side of the road. The optics and electronics of the system is described and preliminary results are presented from field trials. Extensions to the spectrometer in terms of sensitivity by detection of the more intense first overtone of carbon monoxide around 2320 nm are described, in addition to further work on other species of interest.

Carbon Dioxide↗
PubMed2001

Trends in provision of distal arterial reconstruction in Scotland 1989-1999.

OBJECTIVES: to establish if access to distal arterial reconstructive surgery is equally distributed within the health boards of Scotland and to establish if any variations in practice are reflected in lower limb amputation. METHODS: a retrospective, descriptive study using hospital discharge data (Scottish Morbidity Record-1) from 1989 to 1999. RESULTS: the rate of distal arterial reconstruction in Scotland increased from 0.9 per 100 000 population in 1989, peaked at 2.6 per 100 000 in 1994 and has since declined steadily to 1.6 per 100 000 in 1999. There was up to 17-fold variation in annual rates of distal reconstruction between the 12 mainland health boards. The variations in distal reconstruction between the health boards were not reflected in variations in amputation rate nor is the decline in distal reconstruction easily explained by increased angioplasty. CONCLUSIONS: rates of distal arterial reconstruction in Scotland fall well below those in other European countries. It is likely that insufficient distal operations are undertaken to sufficiently impact on amputation rates. The study recommends an increased provision of specialist vascular surgical expertise in Scotland.

Amputation, Surgical↗
PubMed2000

Extracranial arterial aneurysms: a cause of crescendo transient ischaemic attacks.

Crescendo transient ischaemic attacks (TIAs) should be regarded as a medical emergency. Patients require hospitalisation with urgent assessment and symptom control with anticoagulant therapy. We report on three patients, all of whom had atherosclerotic aneurysmal disease of the extracranial arterial circulation who presented with crescendo TIAs. The possibility of extracranial aneurysmal disease should always be considered and excluded.

Aged↗
PubMed1999

Audit of the effect of introducing local guidelines for referral for carotid duplex scanning.

Guidelines for referral of patients for carotid duplex scanning were introduced stating that scans were only indicated for patients with hemispheric localising symptoms or asymptomatic bruits. A 19% reduction in referral rate was seen for new scans in a one year period. The number of "inappropriate" requests fell from 27.6% in 1994 to 12.8% in 1995. There was no reduction in the numbers of patients identified with effectively occult asymptomatic disease who may have been suitable for surgery in the same period. Guideline introduction had the effect of reducing unnecessary scans without any effect on the overall pick-up, rate for carotid disease.

Carotid Stenosis↗
PubMed1999

Accuracy of the recording of operative events by the Scottish Morbidity Record 1 (SMR1) for a teaching hospital vascular unit.

OBJECTIVE: To determine the accuracy of operative data collected for the Scottish Morbidity Record 1 (SMR1). DESIGN: Retrospective comparative analysis of operative data recorded by the Scottish Office Information and Statistics Division (ISD) with that recorded in a locally held vascular database where the clinical information was entered by medical personnel. SUBJECTS: All patients with a codeable operative procedure carried out under the care of a single consultant vascular surgeon in a Regional Vascular Unit in 1994. RESULTS: A total of 840 admissions involving at least one OPCS4 code were recorded in the Vascular Database and 793 by the Scottish Office ISD. Although there was good agreement of the total number of operations and admissions, operative codes for 23 patients undergoing major abdominal aortic surgery and 19 undergoing major limb reconstruction were not recorded by the ISD. This represents 14% of total major arterial reconstructions in a single year. CONCLUSION: Accurate data collection has wide implications for research, monitoring future health trends, and planning hospital bed numbers. SMR1 data may accurately record total number of admissions and operations but is poor at distinguishing between those admissions that may be resource-intensive.

Cardiovascular Surgical Procedures↗
PubMed1997

Results and resource implications of treating end-stage limb ischaemia.

PURPOSE: To quantitate the workload, resource requirement and outcome involved in the management of patients with chronic limb-threatening ischaemia when adopting an aggressive reconstructive policy. METHODS: Prospective clinical audit of all patients with severe lower limb ischaemia presenting to a single specialist Vascular Surgeon in a 3 year period. RESULTS: A total of 228 patients were treated with 275 severely ischaemic limbs. Two hundred and thirty-five limbs (85.5%) had procedures to improve blood supply, 19 (6.9%) underwent primary amputation and 21 (7.7%) were treated conservatively. The principal outcome measures were limb-salvage, death and graft patency. The cumulative limb-salvage, including those undergoing primary amputation, at 30 days, 1, 2, 3 and 4 years was 94.2%, 82.7%, 73.1%, 68.3% and 65.3% respectively. The cumulative patient survival was 91.7%, 69.2%, 58.1%, 47.9% and 40.6% for the same intervals. For reconstructive vascular surgery, excluding amputation and rehabilitation, a total of 383 hospital admissions were required covering 7343 hospital days, 64.5% of patients were managed in a single admission. The median duration of stay was 16 days for the first admission. Operations included 361 separate procedures to improve blood supply and 70 major limb amputations. CONCLUSIONS: The management of chronic limb-threatening ischaemia presents major resource implications. An acceptable limb-salvage rate can be achieved although there is a high initial mortality. In view of the poor overall survival any benefits for these patients should be viewed as relatively short-term objectives.

Adult↗
PubMed1997

Glutaraldehyde-tanned bovine carotid artery graft for infrainguinal vascular reconstruction: 5-year follow-up.

OBJECTIVE: To assess the long-term patency of a modified biological conduit, the glutaraldehyde-tanned bovine carotid artery, in above-knee infrainguinal arterial reconstruction. PATIENTS AND METHODS: Prospective follow-up of a cohort of 58 above-knee femoropopliteal grafts in 55 patients. Graft patency was assessed at yearly intervals with doppler ankle pressure measurements. RESULTS: The median follow-up period has been 67 months. Nine grafts occluded within 30 days of surgery and a further 19 graft closures have been observed in the follow-up period. The overall cumulative primary graft patency at 1, 3 and 5 years was 70%, 61% and 56%, respectively. If the 30-day graft failures are excluded, the primary graft patency rises to 83%, 74% and 68% at 1, 3 and 5 years, respectively. Six limbs have been amputated, four above the knee and two below the knee. There were no graft aneurysms and no graft infections. CONCLUSION: Results indicate that the modified bovine carotid artery graft with an above-knee anastomosis does not seem to be inferior to PTFE, but is inferior to reversed vein. Modified biological conduits offer a reasonable alternative to synthetic grafts for infrainguinal arterial reconstruction and appear to maintain acceptable long-term mechanical stability.

Aged↗
PubMed1997

Mesenteric revascularisation for acute-on-chronic intestinal ischaemia.

Eleven patients (eight women) underwent urgent revascularisation for acute-on-chronic mesenteric ischaemia. Four patients had dual vessel and seven single vessel reconstructions. Two patients underwent simultaneous bowel resection and one patient has had three separate grafts to the superior mesenteric artery. There were two peri-operative deaths and three have died in the late follow-up period after 18, 24 and 36 months. The remainder have survived for between five and 63 months. Revascularisation for acute-on-chronic mesenteric ischaemia has been shown to be technically possible and of substantial benefit to patients who would otherwise be treated as terminal cases.

Acute Disease↗
PubMed1996

What are the indications for a carotid duplex scan?

Carotid duplex scanning offers a quick and non-invasive method for detecting extracranial carotid arterial disease. However, the increasing awareness of the association of carotid disease and cerebrovascular symptoms, together with the recognition that carotid endarterectomy offers the possibility of prevention of a major stroke [1], means that requests for investigation are constantly increasing. The Dundee Vascular Laboratory undertakes the majority of carotid duplex scans in the Tayside region and we have found an increasing burden is being placed on a limited resource that is required for other vascular investigations. In 1994 we carried out 1389 carotid examinations of which 929 (66.9%) showed either no abnormality or no more than a 50% stenosis in one vessel. More importantly, of the 1052 new requests 832 (79.1%) fell into the same category. In order to ascertain if the number of new requests could be reduced a retrospective analysis of the referral indications for a carotid duplex scan in the last 5 years has been undertaken.

Adolescent↗
PubMed1996

The potential role of Clostridium perfringens alpha toxin in the pathogenesis of acute pancreatitis.

BACKGROUND: Clostridium perfringens is a bowel commensal that can colonise the biliary tract. It produces the alpha toxin (phospholipase C), which can induce spontaneous tissue necrosis. AIMS: To investigate whether there is any evidence that Clostridium perfringens alpha toxin can be detected in acute pancreatitis. METHODS: Serum samples from 21 patients with acute pancreatitis and 22 controls were assayed for C perfringens phospholipase C as well as anti-phospholipase C IgG and IgM; IgG and IgM anti-toxins were measured by enzyme linked immunosorbent assay. RESULTS: In normal healthy controls there is a very high level of natural anti-toxin of both the IgG and IgM class. Of the 21 patients with acute pancreatitis alpha toxin was detected in five (23.8%). Levels of both IgG and IgM anti-toxin were significantly reduced in acute pancreatitis. CONCLUSIONS: The results suggest that there is an abnormality of the immune status to C perfringens alpha toxin in patients with acute pancreatitis. This may be the result of a release of alpha toxin, although it is difficult to state whether this is a primary or secondary phenomenon in these patients. These preliminary results merit further investigation.

Acute Disease↗
PubMed1995

Symptoms, stenosis and carotid plaque morphology. Is plaque morphology relevant?

OBJECTIVES: To study the relationship between carotid plaque morphology and the degree of stenosis on Duplex ultrasonography and symptoms. DESIGN: Prospective open clinical study. METHODS: 2,590 patients with 5,180 carotid arteries were scanned, 4,560 were initially analysed in terms of symptoms but 54 were excluded, leaving a total of 4,258. RESULTS: Localising symptoms were present with respect to 1,342 vessels (29.4%). Two-thirds of symptomatic patients had normal carotid arteries. Tight stenosis (80-99%) was more likely to be associated with symptoms than low-grade (20-79%) stenosis (chi 2 = 28.0, p < 0.0001). Plaque type was identified in 1,558 bifurcations (36.6%). Heterogeneous type I & II plaques accounted for one third of plaques. There was a relationship between plaque morphology and degree of stenosis. At < 20% stenosis only 4.4% of plaques were heterogeneous whereas at 80-99% stenosis 84.5% of plaques were heterogeneous. Amaurosis fugax was the only symptom that had any association with a particular plaque morphology. Seventy-two percent of plaques associated with this symptom were heterogeneous in nature. CONCLUSIONS: Carotid plaque morphology and degree of internal carotid stenosis are mutually dependent factors and both reflect the severity of atherosclerotic disease. Plaque morphology does not add to the sensitivity of stenosis in predicting the presence of symptoms.

Blindness↗