Search PubMed⌕ Search

Biomedical subjects

M L Nicholson

Publications and source records attributed to M L Nicholson.

At least 127 records · Page 7Linked to original sources
PubMed1998

Nitric oxide and renal reperfusion injury: a review.

BACKGROUND: Nitric oxide (NO) is a ubiquitous molecule with a role in both normal homeostasis and pathophysiological processes. However, the role it plays in renal ischaemia reperfusion injury is matter of some contention. METHOD AND RESULTS: This paper précis the biology and biosynthesis of NO before concentrating on the function of NO in renal ischaemia reperfusion injury. What emerges is a picture of some clarity about the normal physiological role of NO but some discord regarding the generation and function of postischaemic nitric oxide. Some of the reasons for this are explored in more detail. CONCLUSIONS: Clarity on the precise effect of postischaemic NO will remain elusive without the in vivo measurement of NO in experimental models.

Animals↗
PubMed1998

Arteriovenous fistula using transposed basilic vein.

BACKGROUND: Patients who need long-term haemodialysis often require multiple operations to maintain their vascular access. The options for secondary or tertiary access procedures may become increasingly limited. Prosthetic conduits are commonly used in difficult cases but are associated with a high incidence of complications. METHODS: The brachial artery-transposed basilic vein arteriovenous fistula has been used in preference to a prosthetic graft on 31 occasions. RESULTS: There were no technical failures and 28 of these fistulas matured. No major infective complications occurred. CONCLUSION: This procedure should be considered before resorting to a prosthetic graft for vascular access.

Adult↗
PubMed1998

New model of renal warm ischaemia-reperfusion injury for comparative functional, morphological and pathophysiological studies.

BACKGROUND: Renal warm ischaemia-reperfusion injury is pertinent to vascular and transplant surgery. While established models provide functional and morphological data the authors wanted to be able to correlate this with the underlying pathophysiology at any chosen time point, thus allowing future interventional effects on reperfusion injury to be evaluated. METHODS: In a rodent model bilateral renal warm ischaemia (15-60 min) and then reperfusion (20 or 80 min) before nephrectomy allowed for analysis of early reperfusion pathophysiology. The remaining kidney provided functional data (glomerular filtration rate (GFR)) at days 2 and 7 before nephrectomy for late analysis and morphology using a new grading system. RESULTS: Acceptable survival rate (ten of 12 animals) was seen with up to 45 min of warm ischaemia. Renal function was impaired at day 2 following 30-60 min of warm ischaemia (P< 0.01) and day 7 in the 45- and 60-min groups (P < 0.05 and P < 0.01 respectively). Strong correlation existed between duration of ischaemia and GFR at day 2 (r2=0.88) and day 7 (r2=0.95). Histological damage in the cortical tubules was evident in the 45- and 60-min groups (P< 0.01). CONCLUSION: This new model allowed comparative functional, morphological and pathophysiological studies while minimizing the number of animals required. Overall 45 min of warm ischaemia gave significant, recoverable injury and is recommended for investigating renal reperfusion injury.

Animals↗
PubMed1998

Nitric oxide generation is increased in experimental renal warm ischaemia-reperfusion injury.

BACKGROUND: Nitric oxide has a clearly defined place in normal renal homoeostasis while there is a continuing debate as to its role under pathophysiological conditions. This study investigated the role of nitric oxide in a model of renal warm ischaemia-reperfusion injury. METHODS: Groups of rats underwent bilateral renal warm ischaemia (for 15-60 min) followed by reperfusion (20 or 80 min) before unilateral nephrectomy for measurement of renal nitric oxide (as nitroxides) and oxidative damage. Renal function was measured on days 2 and 7 before killing and nephrectomy. A further group received the nitric oxide synthase inhibitor N(G)-nitro L-arginine methyl ester (L-NAME; 50 mg per kg body-weight) before induction of warm ischaemia. RESULTS: In early reperfusion there was a correlation between the duration of warm ischaemia (15-45 min) and renal nitrate (r2=0.97) which increased from a mean(s.e.m.) baseline value of 95(5.9) to 208(17.3) nmol per mg protein following 45 min of warm ischaemia. Levels were further raised at 80 min and maintained through to day 7 (241(12.5) nmol per mg protein in 45-min group). This rise was attenuated by L-NAME (P< 0.01) as was the early rise in oxidative damage seen otherwise. By day 7, however, oxidative damage was increased (all P< or = 0.01). CONCLUSION: Renal nitric oxide increased early in recoverable warm ischaemia-reperfusion injury and remained raised to day 7. Nitric oxide synthase inhibition ameliorated early but exacerbated late damage suggesting that the early burst of nitric oxide is cytotoxic but that overall nitric oxide may exert a cytoprotective effect.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1998

Surgical anatomy of the parathyroid glands in secondary hyperparathyroidism.

Parathyroidectomy is commonly required in patients with hyperparathyroidism secondary to end stage renal failure. Most descriptions of parathyroid anatomy are based on studies of normal glands. The details of parathyroid anatomy in 60 consecutive patients undergoing total parathyroidectomy for hyperparathyroidism secondary to renal failure are presented. Comparisons are made with the anatomical locations in series of normal glands. Based on these findings a strategy is proposed for the successful identification of all the parathyroid glands in patients undergoing parathyroidectomy for renal hyperparathyroidism.

Adolescent↗
PubMed1997

Urological complications in renal transplantation: impact of a change of technique.

OBJECTIVE: To determine whether the change from the Leadbetter-Politano technique to a stented extravesical technique for the vesico-ureteric anastomosis in renal transplantation has altered the incidence of urological complications. PATIENTS AND METHODS: Data were retrieved from a prospective computerized database and by case-note review on 248 consecutive renal transplants performed between January 1990 and June 1996. The characteristics of the donor. recipient and organ were noted, together with the technique used for the vesicoureteric anastomosis and the occurrence of major and minor urological complications. RESULTS: The Leadbetter-Politano technique was used in 140 transplants and the stented extravesical technique in 108. There were no significant differences in the donor, recipient or organ characteristics between the groups. The stented extravesical technique was associated with a significantly lower rate of major complications (< 2%) and clinically significant haematuria than with the Leadbetter-Politano technique. CONCLUSION: Changing from the Leadbetter-Politano technique to a stented extravesical technique for the vesico-ureteric anastomosis has been a major factor in reducing the incidence of urological complications in our transplant practice.

Adolescent↗
PubMed1997

Randomised trial of subcuticular suture versus metal clips for wound closure after thyroid and parathyroid surgery.

A randomised trial was conducted to compare the results of neck wound closure using metal (Michel) clips or subcuticular suture. All operations were performed using a standardised technique, which included wound infiltration with 10 ml bupivacaine and adrenaline solution, no strap muscle division and the use of suction drains. All the collar incisions and wound closures were performed by the same surgeon. At the end of each operation patients were randomised to wound closure by either metal clips (n = 38) or a continuous 3/0 prolene subcuticular suture (n = 42). Daily postoperative pain scores and the discomfort caused by clip/suture removal were recorded. The cosmetic appearance of each wound was scored by the patient, the surgeon, and an independent observer using verbal response and linear analogue scales. The two study groups were well matched for age, sex, indication for surgery and operation performed. There were no differences in postoperative pain scores between clips and sutures. Removal of subcuticular sutures was performed more quickly (P < 0.0001) and caused less pain (P < 0.0001, visual analogue scale; P = 0.0042, verbal response scale) than the removal of clips. At the time of discharge, the cosmetic appearance scores generated by the surgeon, patient and independent observer were higher for suture closed wounds than clips. However, by 3 and 6 months follow-up there were no differences in cosmetic appearance between the two methods of closure. Only very short-term cosmetic results are influenced by the type of wound closure in thyroid and parathyroid surgery, but sutures are quicker and less painful to remove than Michel clips.

Adult↗