Search PubMed⌕ Search

Biomedical subjects

J H Webster

Publications and source records attributed to J H Webster.

At least 37 records · Page 2Linked to original sources
PubMed1987

Duplex ultrasound assessment of femorodistal grafts: correlation with angiography.

Fifty-eight grafts have been assessed using duplex scanning and ankle brachial pressure indices. This assessment is compared with the findings by angiography. Eighteen grafts were occluded and 40 patent. Duplex scanning defined graft status with a greater accuracy than pressure indices. Pressure indices alone would not differentiate "satisfactory" grafts from those with localised, haemodynamically significant disease. Only 55% of those grafts with localised stenoses demonstrated a fall of greater than 0.2 in ankle brachial pressure index after exercise. When the information obtained using pressure indices and duplex scanning was combined non-invasive assessment had a sensitivity of 86% and specificity of 94% for detection of localised, haemodynamically significant disease in patent grafts. Haemodynamically significant disease, as defined by angiography, can be detected and localised with duplex scanning complementing the use of pressure indices in graft assessment.

Aged↗
PubMed1987

The success of in situ vein grafting: early results in comparison with the reversed vein technique.

In a 6-year retrospective analysis of 341 consecutive femorodistal autogenous vein bypasses, results from 104 in situ veins (IS) were compared with 209 reversed veins (RV). The groups were comparable for age, sex, diabetes, indication for surgery and calf vessel run-off, but a significantly higher proportion of the in situ group had a lower distal anastomosis (16% IS, 6% RV, chi 2 = 7.1 P less than 0.01). Overall, operative mortality was 2% and early graft failure was similar in both groups (11% IS, 12% RV, P = NS). Cumulative graft patency rates were 74% IS, 79% RV at one year and 71% IS, 71% RV (P = NS) at three years. Cumulative limb survival rates were 81% IS, 85% RV at one year and 79% IS, 81% RV [P = NS) at 3 years. These results demonstrate that the in situ technique has been used in a wider variety of patients and yielded similar early and intermediate term results to reversed vein.

Adult↗
PubMed1986

Below knee femoropopliteal bypass in severe ischaemia: results using EXS Dacron and human umbilical vein.

This paper reports our preliminary experience using EXS Dacron for infrageniculate femoropopliteal grafts in elderly patients, the majority (78%) suffering critical ischaemia. A comparison is made with human umbilical vein grafts (HUV). Ninety patients (mean age 69 years) with 92 grafts (42 EXS, 50 HUV) were followed up using ultrasound imaging to detect patency (median follow up 26 weeks (range 1-292)). Two and one year cumulative survivals were 57% and 80% for EXS Dacron and 39% and 48% for HUV respectively. Early failure of HUV grafts accounted for most but not all of the difference in survival (P = 0.0012, Wilcoxon Breslow). Graft kinking was not seen in EXS grafts and in only 2 HUV. Poor calf vessel run off was related to early graft occlusion (P = 0.01; Savage, Mantel Cox). This preliminary experience with EXS Dacron is encouraging and suggests the need for a formal randomised study.

Aged↗
PubMed1985

Oxygen tension on the skin of the gaiter area of limbs with venous disease.

We examined the levels of oxygen on the skin of the gaiter areas of limbs with venous disease using a Roche Transcutaneous pO2 Monitor to determine whether hypoxia contributes to the skin changes and ulceration associated with severe venous disease. We studied patients with superficial varicose veins and no skin changes (Group 1: n = 25), patients with skin changes and healed ulcers (Group 2: n = 15), and an age matched normal control group (controls: n = 25). TcpO2 measurements were taken 5 cm above the medial malleolus with the limb both horizontal and vertical using a Roche Transcutaneous pO2 Monitor. A standard heel-raising test using a Medisonics Photoplethysmograph indicated the degree of venous insufficiency present. Results show that Group 1 patients and controls have similar skin oxygen levels (Group 1: TcpO2 66.48 + 14.12 mmHg; controls: TcpO2 61.60 +/- 11.02 mmHg) whereas those with skin changes and ulceration have significantly lower oxygen levels (Group 2: TcpO2 46.57 +/- 9.70 mmHg, t = 4.29, P less than 0.001). Group 2 patients did not show a significant rise in TcpO2 levels in the standing position whereas Group 1 patients and controls did (t = 2.6, P less than 0.02). PPG post-exercise recovery times confirmed differences between the three groups. These findings show that significant skin hypoxia occurs on the gaiter area of limbs with severe venous disease and support the concept of an oxygen diffusion block.

Acute Disease↗
PubMed1984

Prediction of amputation wound healing: the role of transcutaneous pO2 assessment.

With the recent trend towards more distal lower limb and below-knee amputation for peripheral vascular disease, failure of amputation healing remains a common clinical problem. There is an urgent need for more objective measures of selecting the most appropriate distal amputation level compatible with healing. Oxygen availability is the final arbiter of tissue viability and healing potential, and we have shown that the measurement of transcutaneous pO2 (TcpO2) accurately reflects the degree of ischaemia in the lower limb. In 59 patients having 62 amputations for peripheral vascular disease significantly lower TcpO2 levels were related to amputation failure. Below-knee amputations with a pre-operative below-knee TcpO2 of above 35 mmHg always healed, and failures had levels of 35 mmHg or less. Nine out of sixteen patients having above-knee amputations had pre-operative below-knee TcpO2 values well above 35 mmHg, suggesting that they may possibly have undergone successful below-knee amputation. No correlation between ankle systolic pressure and amputation healing was found. TcpO2 measurement is simple, non-invasive and reliable and offers an exciting research advance in the assessment of effective tissue perfusion.

Amputation Stumps↗
PubMed1982

Smoking, ignorance, and peripheral vascular disease.

The effect of the surgeon's advice to give up smoking was studied in a group of 43 patients with peripheral vascular disease (PVD), using blood carboxyhemoglobin levels to detect deception. Only seven of 40 patients (17.5%) actually stopped smoking, but the remainder appeared fairly honest in reporting their continued habits. Few patients were aware of the possible harmful effect of smoking on the peripheral arteries. The 43 patients with PVD who smoked had significantly higher carboxyhemoglobin levels than a group of 25 smokers without PVD although their cigarette consumption was the same. This suggests that carboxyhemoglobin levels may provide a better indication of the risk of smoking than overall cigarette consumption alone in the development of PVD.

Adult↗
PubMed1982

Oxygen tension of the skin of ischemic legs.

Using a Kontron Roche Transcutaneous Oxygen Monitor, we measured oxygen tension on the skin of the legs at three sites in patients with peripheral vascular disease and group of controls. Significant decreases in oxygen tension occurred in the patient groups, which correlated well with ankle systolic pressure, with differences between those with claudication and those with rest pain. These results suggest that in limbs with claudication, significant skin hypoxia may exist during rest in spite of reportedly normal skin and muscle blood flow. The progressive decrease in skin oxygen tension down a limb with occlusive vascular disease may play a significant role in skin healing.

Aged↗
PubMed1981

Resistance to benzimidazole anthelmintics in equine strongyles. 1. Frequency, geographical distribution and relationship between occurrence, animal husbandry procedures and anthelmintic usage.

A survey was conducted to determine whether benzimidazole resistant populations of equine strongyles are present in New South Wales and north central Victoria; what is their frequency and geographical distribution; which species are involved; and whether different methods of parasite control could be related to the occurrence and frequency of anthelmintic resistant populations. Resistant populations of strongyles were found over wide areas of New South Wales and in north central Victoria. There was no relationship between geographical location and the occurrence of benzimidazole resistance. The species involved were small strongyles of the sub-family Cyathostominae. There was a direct correlation between the occurrence of resistance (including the level at which it is present) and the frequency of use of benzimidazole anthelmintics. Examination of management practices showed that resistance is not an important problem on farms where different chemical classes of anthelmintics were used in a slow rotation programme; combination anthelmintic therapy (for example, benzimidazole/piperazine/organophosphates) was used and anthelmintic treatment was given at intervals of not less than 16 weeks. Tentative suggestions are made for the control of small strongyles in the light of an emerging resistance problem.

Animal Husbandry↗
PubMed1981

Resistance to benzimidazole anthelmintics in equine strongyles. 2. Evidence of side-resistance, and susceptibility of benzimidazole-resistant strongyles to non-benzimidazole compounds.

The susceptibility of a known thiabendazole-resistant population of small strongyles to anthelmintics of both benzimidazole and non-benzimidazole groups, was determined. In the first study, 42 horses infected with thiabendazole-resistant small strongyles were allocated to 6 groups. Treatment groups received one of the following anthelmintics: mebendazole, febantel, febantel plus trichlorphon, morantel tartrate, or a combination of thiabendazole, piperazine and trichlorphon. Morantel tartrate and the thiabendazole/piperazine/trichlorphon combination produced highly significant (p less than 0.001) reductions in faecal strongyle egg counts 20 days post-treatment. Mebendazole, febantel and febantel plus trichlorphon failed to reduce strongyle egg counts significantly. Larval culture and differentiation indicated that in all cases of anthelmintic failure, small strongyles of the sub-family Cyathostominae were involved. Eighteen horses from groups in which treatment had failed were re-allocated to 3 groups. Treatment with either morantel tartrate or haloxon was highly efficient in reducing faecal strongyle egg counts. In the final study, fifty-four horses, infected with benzimidazole-resistant small strongyles were allocated to 10 groups. On day zero, each treatment group received one of the following anthelmintics: thiabendazole, cambendazole, mebendazole, oxibendazole, piperazine, thiabendazole/piperazine, cambendazole/piperazine, mebendazole/piperazine or oxibendazole/piperazine. Oxibendazole, piperazine and the benzimidazole/piperazine combinations produced highly significant reductions in faecal strongyle egg counts 20 days post-treatment (p less than 0.001). When administered alone, benzimidazole anthelmintics failed to reduce strongyle egg counts significantly, with the exception of oxibendazole. Larval culture and differentiation indicated that in all cases of anthelmintic failure, the species involved were small strongyles of subfamily Cyathostominae. There was no significant increase in benzimidazole resistance level (based on in vitro assay) as a result of drug treatment, over one generation.

Animals↗
PubMed1980

Oligodendrogliomas. I. A clinical study of cerebral oligodendrogliomas.

Fifty-four patients with oligodendroglioma presented in the past 15 years. In contrast to some widely taught concepts, oligodendrogliomas occured largely in the frontotemporal area of both cerebral hemispheres with two peaks of age incidence: one small peak in childhood, and the highest incidence in the middle-aged adult. Seizures, either major and/or minor, were the most common clinical manifestations (average 87%). Cerebral angiography and pneumography were the most reliable and useful diagnostic procedures, as well as the promising CAT scan. All 24 patients who underwent combined modalities of treatment with radical surgery and postoperative radiation therapy survived at least five years, and 2 out of 11 patients treated by surgery alone failed to survive the five-year follow-up period in addition to two recurrences. Postoperative radiation treatment is considered quite effective and indicated in most cases because complete removal of the tumor is not always possible.

Adolescent↗
PubMed1980

Irradiation injury to large arteries.

Four cases of irradiation injury to large arteries are presented and the literature is reviewed. Three patterns of injury have emerged. 1. Intimal damage resulting in mural thrombosis presenting within 5 years of irradiation. 2. Fibrotic occlusion presenting within 10 years of injury. 3. A predisposition to the development of atheroma together with periarterial fibrosis associated with a latent interval of 20 or more years. The treatment of choice is a bypass procedure of the arterial lesion.

Adult↗
PubMed1979

Astrocytoma in children. A review of 79 cases--1960-1976.

Seventy-nine children with histologically proven astrocytomas, 32 cerebral, 30 cerebellar, 9 thalamic, 6 optic nerve, and 2 in the 4th ventricular floor were reviewed retrospectively. Seventy-one per cent of the astrocytomas were well differentiated. Unlike adult astrocytomas, there was slight female predominance in our group. Cerebral astrocytomas were more frequent beyond nine years of age. The overall five-year survival rate of cerebral astrocytomas was 95% (19/20) for well-differentiated, and 19% (2/12) for poorly-differentiated tumors. In cerebellar astrocytomas the survival rates were 75% (18/24) and 33% (2/6) respectively.

Adolescent↗
PubMed1978

Ruptured abdominal aortic aneurysms.

The results of operation in 76 patients with a ruptured abdominal aortic aneurysm are presented with an analysis of the cause of operative death. Overall mortality was 58 per cent and preoperative hypotension significantly increased mortality; deterioration while awaiting operation made a successful outcome particularly unlikely. No group could be identified, however, in which operation was without hope of saving life, and age alone should not contraindicate surgery.

Aged↗