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Biomedical subjects

N J London

Publications and source records attributed to N J London.

At least 37 records · Page 2Linked to original sources
PubMed2000

Human islet autotransplantation to prevent diabetes after pancreas resection.

In severe cases of chronic pancreatitis pain relief can often only be achieved by pancreas resection, however this may render the patient diabetic. In an effort to prevent diabetes some patients may be suitable for a simultaneous islet autotransplant. The last report from the International Islet Transplant Registry has reported 222 cases. This review discusses the current progress in human islet autotransplantation.

Chronic Disease↗
PubMed2000

Studies of a new multi-layer compression bandage for the treatment of venous ulceration.

This study aimed to develop an alternative graduated compression bandage for the treatment of venous leg ulcers. Alternative bandage components were identified and assessed for optimal performance as a graduated multi-layer compression bandage. Subsequently the physical characteristics and clinical efficacy of the optimal bandage combination was prospectively examined. Ten healthy limbs were used to develop the optimal combination and 20 limbs with venous ulceration to compare the physical properties of the two bandage types. Subsequently 42 consecutive ulcerated limbs were prospectively treated to examine the efficacy of the new bandage combination. The new combination produced graduated median (range) sub-bandage pressures (mmHg) as follows: ankle 59 (42-100), calf 36 (27-67) and knee 35 (16-67). Over a seven-day period this combination maintained a comparable level of compression with the Charing Cross system, and achieved an overall healing rate at one year of 88%. The described combination should be brought to the attention of healthcare professionals treating venous ulcers as a possible alternative to other forms of multi-layer graduated compression bandages pending prospective, randomised clinical trials.

Bandages↗
PubMed1999

An investigation into the distribution of different collagen types within adult and juvenile porcine pancreata.

One of the difficulties of porcine islet isolation is their fragility during collagenase digestion. The object of this study was to determine the distribution of 4 different collagen types within adult and juvenile porcine pancreata. Five different areas from each pancreas were analysed by light microscopy. The distribution of collagen types I, IV, V and VI were measured within the interlobar, intralobular (acinar), peri-insular and intra-islet regions. Their was an abundance of collagen type VI compared to I, IV and V in both the interlobar and intralobular septa in both juveniles (P<0.001) and adults (P<0.001). The periinsular collagen content also showed diversity. This was mainly attributable to the distribution of collagen type I (weak) and type VI (intense) in both adults and juveniles. In general, the peri-insular capsule was fragmentary and contained less than 50% of the total islet circumference. The latter finding taken together with the distributions of different collagen types can partly explain some of the variability of porcine islet isolation.

Animals↗
PubMed1999

Pancreatic islet autotransplantation combined with total pancreatectomy for the treatment of chronic pancreatitis--the Leicester experience.

Islet autotransplantation offers the potential for preventing the surgically induced diabetes that is an inevitable consequence of total pancreatectomy. This paper describes the first islet autotransplant programme in the United Kingdom and the first series in the world to use the spleen as a site for the islet graft. Over an 11 month period, 7 patients underwent total pancreatectomy for chronic pancreatitis combined with a simultaneous islet autotransplant. All 7 patients had normal glucose-tolerance levels and normal C-peptide levels pre-operatively. In 6 patients, islets were embolized into the liver via the portal vein (median transplanted volume=8.5 ml). In addition, 3 patients received islets into the splenic sinusoids via a short gastric vein (median transplanted volume=4 ml). One patient received islets into the spleen alone. One patient died of a stroke 4 weeks post transplantation. Two patients have achieved insulin independence, with a further two patients achieving "transient" insulin independence (<1 month). The remaining 2 patients, although requiring reduced insulin doses, have not achieved insulin-independence. However, all patients have C-peptide levels within the normal range. In trying to explain these findings, split proinsulin levels were measured and found to be elevated. High levels of split proinsulin cross react with the C-peptide assay and this would explain the falsely elevated C-peptide levels. Indeed insulin levels in these patients were all below the normal range. These findings would suggest that the use of C-peptide levels as the "gold standard" for monitoring islet autograft function, may require reappraisal.

C-Peptide↗
PubMed1999

Experience of supraclavicular exploration and decompression for treatment of thoracic outlet syndrome.

The purpose of this study was to assess the symptomatic outcome of patients with thoracic outlet syndrome who underwent decompression of the thoracic outlet. In our unit we prefer the supraclavicular approach, performing anterior scalenectomy with excision of fibrous bands or cervical ribs if present. Operative details were gained by theater logbook and case note review. Over a 6-year period, 31 patients (37 limbs) underwent thoracic outlet decompression. Of the 37 affected limbs, the indications for surgery were a combination of both neurological and vascular symptoms in 24 patients (65%), neurological symptoms in 24 (65%), and 4 patients (11%) had vascular symptoms alone. All patients were assessed for postoperative outcome either at out-patient clinics or by personal contact. From the results of this study we concluded that supraclavicular scalenectomy and cervical rib excision with selective first rib excision is a safe and effective procedure for most patients with thoracic outlet syndrome.

Adult↗
PubMed1999

Angiogenesis and the atherosclerotic carotid plaque: an association between symptomatology and plaque morphology.

PURPOSE: Symptomatic carotid disease resulting from generation of thromboemboli has been associated with plaque instability and intraplaque hemorrhage. These features of the lesion could be influenced by the fragility and position of neovessels within the plaque. The purpose of this study was to determine whether any association exists between neovessel density, position, morphology, and thromboembolic sequelae. METHODS: Carotid endarterectomy samples were collected from 15 asymptomatic patients with greater than 80% stenoses and from 13 highly symptomatic patients who had suffered ipsilateral carotid stenotic events within 1 month of surgery. Both groups were matched for gender, age, risk factors, degree of carotid artery stenosis, and plaque size. Samples were stained with hematoxylin/eosin and van Geison. Immunohistochemistry was performed by using an endothelial specific antibody to CD31. Plaques were assessed for histologic characteristics, and neovessels were counted and characterized by size, site, and shape. RESULTS: There were significantly more neovessels in plaques (P <.00001) and fibrous caps (P <.0001) in symptomatic compared with asymptomatic plaques. Neovessels in symptomatic plaques were larger (P <.004) and more irregular. There was a significant increase in plaque necrosis and rupture in symptomatic plaques. Plaque hemorrhage and rupture were associated with more neovessels within the plaque (P <.017, P <.001) and within the fibrous cap (P <.046, P <.004). Patients with preoperative and intraoperative embolization had significantly more plaque and fibrous cap neovessels (P <.025, P <.001). CONCLUSION: Symptomatic carotid disease is associated with increased neovascularization within the atherosclerotic plaque and fibrous cap. These vessels are larger and more irregular and may contribute to plaque instability and the onset of thromboembolic sequelae.

Arteriosclerosis↗
PubMed1999

In situ replacement of infected aortic grafts with rifampicin-bonded prostheses: the Leicester experience (1992 to 1998)

PURPOSE: Prosthetic graft infection after aortic aneurysm surgery is a life-threatening complication. Treatment options include total graft excision and extra-anatomic bypass grafting or in situ replacement of the graft. The latter option is gaining increasing popularity, but the long-term outcome remains uncertain, particularly in light of the increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA). We performed a prospective nonrandomized study to assess the outcome after graft excision and in situ replacement with a rifampicin-bonded prosthesis for the treatment of major aortic graft infection. METHODS: In a 6-year period from January 1992 to December 1997, 11 patients (eight men, three women) with major aortic graft infection underwent total graft excision and in situ replacement with a rifampicin-bonded prosthesis. The median age of the patients was 66 years (range, 49 to 78 years). Four patients had a hemorrhage from an aortoenteric fistula, three had a retroperitoneal abscess, two had graft occlusion, one had a perigraft collection shown by means of computed tomography, and one had a ruptured suprarenal false aneurysm. Organisms were cultured from 10 patients. RESULTS: MRSA was isolated in two patients, both of whom had originally undergone repair of a ruptured abdominal aortic aneurysm. Two patients died (18.2%) within 30 days, and three patients (27.6%) had nonfatal complications (peritoneal candidiasis, transient renal impairment, and profound anorexia). Two patients died late in the follow-up period. Seven patients remain alive and clinically free of infection. CONCLUSION: The long-term results after total graft excision and in situ replacement with a rifampicin-bonded prosthesis appear to be favorable. However, MRSA aortic graft infection appears to be associated with a poor prognosis.

Aged↗
PubMed1999

Colour-coded duplex imaging and dependent Doppler ultrasonography in the assessment of cruropedal vessels.

BACKGROUND: It has been suggested that ultrasonography could replace diagnostic arteriography in the assessment of patients who present with leg ischaemia. This study investigated a group of consecutive patients who had femorodistal bypass and who were assessed before operation with colour-coded duplex and dependent Doppler insonation alone. METHODS: Thirty-seven consecutive patients with critical lower limb ischaemia underwent surgical exploration with a view to femorodistal bypass. Results of preoperative colour-coded duplex and dependent Doppler insonation were compared with intraoperative arteriograms and surgical findings. RESULTS: There was very good agreement between colour-coded duplex imaging and dependent Doppler insonation with intraoperative angiography and surgical findings in the prediction of the optimal run-off vessel (kappa = 1.0) and the site of the distal anastomosis (kappa = 0.85; 95 per cent confidence interval 0.71-1.0). There was also very good agreement between dependent Doppler insonation and intraoperative arteriography (kappa = 1.0) in predicting pedal arch patency and the predominant feeding vessel. CONCLUSION: Assessment of leg arteries before femorodistal bypass can be performed accurately with non-invasive colour-coded duplex imaging and dependent Doppler insonation alone, thus obviating the need for preoperative arteriography.

Adult↗
PubMed1999

Role of superficial venous surgery in the treatment of venous ulceration.

BACKGROUND: The aim of this study was to determine the ability of superficial venous surgery to heal venous ulcers in lower legs with isolated superficial venous incompetence. METHODS: This was a prospective study of patients recruited from a venous ulcer assessment clinic. Ulcers were considered venous if the ankle : brachial pressure index was greater than 0.8 and duplex imaging showed venous reflux. Patients with isolated superficial venous incompetence were offered saphenofemoral and/or saphenopopliteal surgery. Neither perforator surgery, skin grafting nor postoperative compression hosiery or bandaging was used. RESULTS: A total of 122 legs with normal deep veins underwent superficial venous surgery. Ninety procedures (74 per cent) were done under local and 32 (26 per cent) under general anaesthesia. Sixty operations (49 per cent) were done as a day case. The median time to healing was 18 (95 per cent confidence interval 14-21) weeks and the cumulative 6-, 12- and 18-month healing rates were 57, 74 and 82 per cent respectively. CONCLUSION: In patients with venous ulceration and isolated superficial venous incompetence, superficial venous surgery can produce ulcer healing in the majority of patients without the need for perforator surgery, postoperative compression bandaging or skin grafting.

Adult↗
PubMed1999

Use of colour duplex imaging to diagnose and guide angioplasty of lower limb arterial lesions.

BACKGROUND: The purpose of this study was to investigate whether colour duplex imaging alone could safely and effectively be used to diagnose lower limb arterial lesions and guide subsequent percutaneous transluminal angioplasty (PTA). METHODS: Patients with discrete lower limb arterial lesions, preferably stenoses, which could be visualized clearly by colour duplex imaging were selected for duplex-guided PTA. Duplex-guided PTA was performed in an operating theatre using conventional balloon catheters. RESULTS: Duplex imaging was used to diagnose and guide PTA of 55 arterial lesions in 50 legs of 45 patients. There were 53 stenoses and two occlusions. The median (range) ankle : brachial pressure index was 0. 86 (0.52-1.10) before dilatation and 1.00 (0.83-1.40) immediately after dilatation (P = 0.0001). There were no complications during or after any of the procedures and 46 of the 47 symptomatic legs were markedly improved at a median follow-up of 23 days. Radiographic imaging was not required for any of the procedures. CONCLUSION: It is possible to diagnose and angioplasty lower limb arterial lesions using colour duplex imaging alone.

Angioplasty, Balloon↗
PubMed1999

Vascularized pancreas allotransplantation--clinical indications and outcome.

AIMS: This review examines the status of vascularized pancreas transplantation as a treatment for Type 1 diabetes mellitus (DM). METHODS: The world literature, with a particular emphasis on data from the International Pancreas Transplant Registry (IPTR), is reviewed and interpreted particularly for clinical indications and outcome. RESULTS: Over 9000 cases of vascularized pancreas transplant (VPT) have been registered, with insulin dependence approaching 82% at 1 year with 94% patient survival. The majority of transplants are simultaneous pancreas and kidney (SPK) transplants, with far fewer pancreas after kidney (PAK) or pancreas transplants alone (PTA). The success rates differ between the procedures but are generally improving as technical advances, improvements in immunosupression and greater experience are gained. The most obvious advantage is an improved quality of life (QoL) but there are risks associated with the procedure and with the immunosuppression. There is some evidence coming to light of a very slow beneficial effect on microvascular complications. CONCLUSIONS: VPT is an attractive option to offer Type 1 DM patients who need or already have a renal allograft. Patients have to decide between the increased surgical risk and the risks of long-term immunosuppression and the benefits of improved QoL. In the absense of end-stage renal failure (ESRF) there is no justification for PTA, except where the diabetes itself poses a greater risk to life than the transplantation procedure.

Diabetes Mellitus, Type 1↗
PubMed1999

Venous ulceration and continuous flow in the long saphenous vein.

OBJECTIVE: To determine the clinical significance of continuous flow in the long saphenous vein in limbs with venous ulceration. DESIGN: Retrospective review. PATIENTS AND METHODS: Review of 1608 consecutive limbs undergoing colour duplex scanning for venous disease over a 43 month period. RESULTS: Continuous flow in the long saphenous vein is seen in 8% of limbs with venous ulceration and in 37% of limbs with deep venous obstruction. Sixty-six per cent of ulcerated limbs with continuous flow in the long saphenous vein had deep venous obstruction, 27% had deep venous reflux with cellulitis and 7% had lymphoedema in addition to venous ulceration. CONCLUSION: Continuous flow in the long saphenous vein in patients with venous ulceration should alert the clinician to the possibility of deep venous obstruction. Such limbs should be treated by compression bandaging with extreme caution.

Blood Flow Velocity↗
PubMed1999

Infrainguinal revascularisation in the era of vein-graft surveillance--do clinical factors influence long-term outcome?

OBJECTIVES: To investigate the variables affecting the long-term outcome of infrainguinal vein bypass grafts that have undergone postoperative surveillance. DESIGN: A retrospective analysis. PATIENTS AND METHODS: Details of 299 consecutive infrainguinal vein grafts performed in 275 patients from a single university hospital were collected and analysed. All grafts underwent postoperative duplex surveillance. Factors affecting patency, limb salvage and survival rates were examined. These factors were gender, diabetes, hypertension, aspirin, warfarin, ischaemic heart disease, run-off, graft type, early thrombectomy, level of anastomoses and indication for surgery. RESULTS: The 6-year primary, primary assisted and secondary patency rates were 23, 47, and 57%, respectively. Six-year limb salvage and patient survival were 68 and 45%, respectively. Primary patency was adversely influenced by the use of composite vein grafts. Early thrombectomy was the only factor that significantly influenced secondary patency. Limb salvage was worse in diabetic limbs, limbs with poor run-off and in grafts that required early thrombectomy. Postoperative survival was better in males, claudicants and in patients who took aspirin. CONCLUSIONS: Although co-morbid factors did not influence graft patency rates, diabetes did adversely effect limb salvage. This study, like others before it, confirms that aspirin significantly reduces long-term mortality in patients undergoing infrainguinal revascularisation.

Angioplasty↗
PubMed1999

A policy of quality control assessment helps to reduce the risk of intraoperative stroke during carotid endarterectomy.

OBJECTIVES: A pilot study in our unit suggested that a combination of transcranial Doppler (TCD) plus completion angioscopy reduced incidence of intra-operative stroke (i.e. patients recovering from anaesthesia with a new deficit) during carotid endarterectomy (CEA). The aim of the current study was to see whether routine implementation of this policy was both feasible and associated with a continued reduction in the rate of intraoperative stroke (IOS). MATERIALS AND METHODS: Prospective study in 252 consecutive patients undergoing carotid endarterectomy between March 1995 and December 1996. RESULTS: Continuous TCD monitoring was possible in 229 patients (91%), while 238 patients (94%) underwent angioscopic examination. Overall, angioscopy identified an intimal flap requiring correction in six patients (2.5%), whilst intraluminal thrombus was removed in a further six patients (2.5%). No patient in this series recovered from anaesthesia with an IOS, but the rate of postoperative stroke was 2.8%. CONCLUSIONS: Our policy of TCD plus angioscopy has continued to contribute towards a sustained reduction in the risk of IOS following CEA, but requires access to reliable equipment and technical support. However, a policy of intraoperative quality control assessment may not necessarily alter the rate of postoperative stroke.

Aged↗