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Biomedical subjects

M L Nicholson

Publications and source records attributed to M L Nicholson.

At least 163 records · Page 9Linked to original sources
PubMed1994

Effect of human leucocyte antigen matching on the incidence of acute rejection in renal transplantation.

The influence of human leucocyte antigen (HLA) matching on the incidence of acute rejection and graft survival was examined in 181 consecutive patients receiving cadaveric renal transplants. Allografts with better HLA-DR and HLA-B matching showed significantly lower rejection rates than less well matched grafts on both univariate (rejection rates 25, 62 and 82 per cent for zero, one and two DR mismatches; P < 0.001) and multivariate analysis. Rejection episodes occurred earlier in mismatched grafts (P < 0.001). Superior matching was associated with improved graft function at 1 year after transplantation (mean serum creatinine level 137, 180 and 225 mumol l-1 for zero, one and two DR mismatches; P < 0.05). No association was, however, demonstrated between the degree of matching and overall graft survival. Good HLA matching reduces the number of acute rejection episodes, producing significant savings in drug costs and hospital stay. Long-term graft function is improved and minimizing early graft damage helps to avoid later development of chronic rejection.

Acute Disease↗
PubMed1994

Comparison of three methods to obtain percutaneous needle core biopsies of a renal allograft.

During 280 renal transplant biopsy procedures, 440 biopsy cores were obtained using three techniques: blind vertical pass, ultrasonographic guidance and ultrasonographic guidance with immediate specimen examination by stereoscopic microscopy. The success rates per procedure in obtaining renal cortex by blind vertical pass, ultrasonographic guidance and ultrasonographic guidance with microscopy were 75, 91 and 100 per cent respectively. Ultrasonographic guidance improves the success rate of percutaneous renal allograft biopsy. The additional use of immediate examination by stereoscopic microscopy yields a 100 per cent success rate for individual biopsy procedures.

Biopsy, Needle↗
PubMed1994

The importance of E-selectin as a marker for renal transplant rejection.

Vascular endothelial cells express membrane bound adhesion molecules which play a direct role in the localization and subsequent movement of leucocytes from the blood into sites of inflammation. E-Selectin is a cytokine induced adhesion molecule, known to be expressed by endothelial cells in inflammatory conditions, which binds to various leucocyte subpopulations. In a prospective study we have investigated the expression and distribution of E-selectin on renal allograft needle biopsies taken from 16 pretransplant kidneys and 119 post-transplant kidneys. Post-transplant biopsies were taken at times of graft dysfunction and at times of normal graft function. Formal histology was also performed and assessed independently. E-Selectin was found predominantly on the intertubular endothelium and on the endothelium of larger vessels. E-Selectin was present, at low intensity, in some pretransplant biopsies and also some post-transplant biopsies which were reported histologically as normal. In post-transplant biopsies taken for dysfunction E-selectin was present in the majority of cases. Expression was strong in biopsies showing acute cellular rejection and this was associated with a CD4 positive cellular infiltrate. Biopsies showing other causes of dysfunction, in particular acute tubular necrosis, also were E-selectin and CD4 positive with lower intensity than those with acute cellular rejection. These results suggest that E-selectin is a good marker for endothelial activation in renal transplant biopsies. Its presence in histologically apparently normal biopsies suggests that its in vivo kinetics may differ from previously reported in vitro kinetics. E-Selectin may be a potential target for therapeutic intervention.

Biomarkers↗
PubMed1994

Obesity as a risk factor in major reconstructive vascular surgery.

In a prospective analysis of 150 consecutive major vascular reconstructions, 104 patients were of normal weight (NW), 33 were overweight (OW) and 13 were obese (OB), as defined by body mass index calculations (BMI = kg/m2). Wound infections were more common in OW than NW patients (10/33 versus 10/104, p < 0.01) and in the OB compared to the NW group (4/13 versus 10/104, p < 0.05). Wound dehiscence was more common in the combined OW and OB groups than the NW patients (3/46 versus 0/104, p < 0.01). Chest infections were more common in OB (4/13) than NW (9/104) patients (p < 0.02). Median (interquartile range) in-patient stay was longer in OB patients [34 (15-41) days] compared to OW [14 (10-19) days, p < 0.001] and NW [11 (8-15) days; p < 0.001] patients. Nonetheless, there were no significant differences in the rates of more major complications or operative mortality between the three groups and early infrainguinal graft patency and limb salvage rates were not different. Only one prosthetic graft infection occurred in this series. In conclusion, despite the higher risk of infective complications, major vascular reconstruction can be performed safely in overweight and obese patients.

Aged↗
PubMed1994

Analysis of factors associated with complications following renal transplant needle core biopsy.

OBJECTIVE: To determine factors associated with complications in patients undergoing renal transplant biopsy. PATIENTS AND METHODS: A total of 210 consecutive renal transplant patients biopsied for acute graft dysfunction or as part of a long term surveillance programme. Biopsies were performed under ultrasound control at two centres (Nottingham City and Leicester General Hospitals). RESULTS: Seventeen patients developed macroscopic haematuria following biopsy (8%). There were no graft losses. In cases where at least one biopsy core contained only renal medullary tissue, there was a significantly higher risk of a post-biopsy bleed (P < 0.001). CONCLUSION: This study demonstrates that even with careful ultrasound guidance, renal transplant biopsy has an important complication rate. Every effort must be made to obtain very superficial biopsies which consist largely or exclusively of renal cortex.

Adult↗
PubMed1994

Endoscopic transthoracic sympathectomy: successful in hyperhidrosis but can the indications be extended?

Endoscopic transthoracic sympathectomy (ETS) has recently become established as a successful treatment for severe palmar and axillary hyperhidrosis. In this unit the indications for ETS have been broadened to include patients with Raynaud's syndrome and critical upper limb ischaemia and this paper is primarily concerned with analysing outcome in relation to the indication for operation. In all, 68 operations have been attempted in 40 patients and complete follow-up details are available on 62 treated limbs. One operation was a technical failure because of an obliterated pleural cavity. In the hyperhidrosis group (n = 28), all the affected areas showed symptomatic improvement at a median follow-up of 17 months. In the Raynaud's group (n = 30), 28 limbs (93%) were improved to some degree at the time of discharge, but at a median follow-up of 18 months only 15 limbs (50%) remained symtomatically improved to some degree. The four upper limbs treated for critical ischaemia were improved by ETS and no amputations were necessary. Significant postoperative chest pain was noted by nine patients (23%). There were three postoperative pneumothoraces, two intercostobrachial neuralgias and one transient Horner's syndrome. The cosmetic result was reported as excellent or good by 97% of patients. As with other forms of surgical thoracic sympathectomy, excellent early results are not maintained in the longer term when ETS is used to treat Raynaud's syndrome. Nevertheless, the greater simplicity and lower morbidity of the endoscopic method suggest that it can be offered to Raynaud's sufferers with greater impunity than open sympathectomies.

Adolescent↗
PubMed1993

Probability of rejection predicted from ultrasonographic measurement of renal transplant swelling.

Serial ultrasonographic measurements of renal transplant cross-sectional area were used to quantify allograft swelling as a diagnostic test of acute rejection. Eighty consecutive episodes of acute allograft dysfunction (rise in creatinine level > or = 10 per cent or > or = 30 mumol l-1) were investigated. Needle core biopsy was performed in all cases to diagnose acute rejection. Rejecting transplants demonstrated a median (interquartile range) swelling of 16.2 (12.1-25.5) per cent compared with 2.2 (-2.0 to 8.4) per cent for non-rejecting organs (P < 0.001). A > or = 10 per cent increase as the diagnostic threshold for rejection yielded a sensitivity of 80 per cent, specificity of 77 per cent, positive predictive value of 85 per cent, negative predictive value of 71 per cent and overall accuracy of 79 per cent. Using a logistic regression model, predictive probabilities of rejection for individual changes in cross-sectional area were calculated. A 20 per cent increase was associated with a predicted probability of rejection of 87 per cent (95 per cent confidence interval 75-94 per cent). There was a significant correlation between the functional severity of rejection and the degree of transplant swelling (rs = 0.63, P < 0.001). Ultrasonographic measurement of renal transplant cross-sectional area is a simple non-invasive test for the diagnosis of acute rejection.

Graft Rejection↗
PubMed1993

Effect of nifedipine on renal transplant rejection.

The effect of early nifedipine therapy on acute renal allograft rejection was studied in 170 adult cadaveric transplant recipients. Acute rejection occurring in the first 3 months after transplantation was diagnosed by Tru-cut biopsy and the severity of each rejection episode assessed histologically. The incidence of acute rejection was significantly lower in patients treated with nifedipine (29 of 80; 36 per cent) than in controls (52 of 90; 58 per cent) (P < 0.01) and there was a higher proportion of histologically mild rejection episodes in the former group (P < 0.01). Multivariate analysis confirmed that nifedipine exerted a significant independent effect on the incidence of early acute rejection. Other factors identified in the multivariate model as influencing rejection were human leucocyte antigen (HLA) matching at the DR locus, blood level of cyclosporin during the first week, HLA matching at the B locus, donor age and donor sex. The 1-year graft survival rate was 88.6 per cent in patients given nifedipine and 63.8 per cent in controls (P < 0.02). These data suggest that nifedipine therapy has a useful role in human renal transplantation.

Adolescent↗
PubMed1993

The influence of primary non-function on the accuracy of ultrasound measurements in the diagnosis of renal allograft rejection.

Daily ultrasonographic measurements of transplant cross-sectional area were used to quantify allograft swelling as a diagnostic test for acute rejection in a series of 120 renal transplants. Initial graft function (IF) occurred in 86 patients (72%) and primary non-function (PNF) occurred in the remaining 34 (28%). An increase in allograft cross-sectional area greater than or equal to 10% was defined as a positive ultrasound scan suggesting an acute rejection episode and was investigated by needle core biopsy. During periods of PNF, allografts with consistently negative ultrasound scans were submitted to needle core biopsy on a weekly basis. The diagnosis of rejection was based exclusively on the histological findings. In the IF group, agreement between ultrasound and histological diagnosis was good (k = 0.63, sensitivity 81%, specificity 83%, positive predictive value 76%, negative predictive value 86% and overall accuracy 82%). In the PNF group, agreement between ultrasound and histology was only fair (k = 0.46, sensitivity 77%, specificity 70%, positive predictive value 69%, negative predictive value 78% and overall accuracy 73%). It is concluded that a degree of allograft swelling is sometimes associated with acute tubular necrosis, and this makes ultrasound measurements of transplant size a less useful technique of monitoring kidneys with PNF.

Biopsy, Needle↗
PubMed1993

Predictive value of bruits and Doppler pressure measurements in detecting lower limb arterial stenosis.

The value of bruits and Doppler ankle pressure measurements as indicators of arterial stenosis was studied in 50 patients with symptoms of lower limb ischaemia. The iliac and femoropopliteal arteries were examined for bruits, ankle systolic pressures were measured before and after an exercise stress test and the results were compared to the findings of digital subtraction angiography (DSA). Patients with occlusive lesions in the iliac and femoropopliteal arteries were not analysed. This left a group of 37 symptomatic legs in which the popliteal pulse was palpable. In this sub-group, DSA demonstrated 25 limbs with arterial stenoses and 12 limbs without evidence of a stenosis. The presence of a bruit had a sensitivity of 80%, a specificity of 75%, a positive predictive value of 87%, a negative predictive value of 64% and an accuracy of 78%. A fall in Doppler ankle pressure of > or = 20 mmHg had a sensitivity of 92%, a specificity of 75%, a positive predictive value of 88%, a negative predictive value of 82% and an accuracy of 86%. When used selectively, clinical examination for bruits has good accuracy and may be of clinical value in the early identification of patients who are suitable for percutaneous transluminal angioplasty.

Adult↗
PubMed1993

Morning emergency operating list: effects of implementation.

The effect of the introduction of a regular morning emergency list for general surgery was assessed immediately on its inception and after 1 year. The main effect was a reduction of the surgical caseload after midnight. The number of surgical procedures carried out between midnight and 0800 dropped from 32% of all emergency procedures in 1989 to 11% in 1991. The number of nights during which emergency surgery took place after midnight dropped from 56% to 30% over the same period. After the adoption of a regular morning emergency list there was no surgery carried out after midnight on 70% of 'duty' nights.

Emergencies↗
PubMed1992

Factors influencing the healing of distal amputations performed for lower limb ischaemia.

A total of 235 toes were amputated during 125 operations on 100 consecutive patients with lower limb ischaemia. The overall amputation wound healing rate for the series was 58.4 per cent and limb salvage was achieved in 66 patients. Toe amputation was performed under local anaesthesia in 57 cases and 32 (56 per cent) of these healed primarily, not significantly different from the healing rate of 41 (60 per cent) of 68 under general anaesthesia. Reconstructive arterial surgery was performed in conjunction with toe amputation in 39 patients; the healing rate with reconstruction was 32 (82 per cent) of 39, significantly better than the 41 (48 per cent) of 86 patients not undergoing bypass surgery (P less than 0.001). There was no difference in healing rates when comparing diabetic and non-diabetic patients. Multiple regression analysis demonstrated that reconstructive arterial surgery was the only factor which had an independent and significant influence on toe amputation healing. The use of local anaesthesia for distal amputation has no deleterious effects on wound healing.

Adult↗