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Biomedical subjects

A D McGregor

Publications and source records attributed to A D McGregor.

At least 19 recordsLinked to original sources
PubMed2006

Consent for plastic surgical procedures.

The objective of this study was to examine patients' attitudes to providing consent for elective plastic and reconstructive surgical procedures and to identify their priorities in terms of information disclosure. Sixty-three consecutive patients attending the elective plastic and reconstructive surgery preadmission clinics at Sandwell Hospital, West Bromwich were prospectively audited by means of a questionnaire which included both open and closed questions. Seventy-five percent of patients volunteered that 'they ought' to have certain information disclosed prior to giving their consent to a surgical procedure. (It was interesting to note that the information they volunteered as wanting to know was not consistently the information that guidelines suggest they are told.) The provision of information is at the centre of the process of valid consent. This study shows the priorities of a group of elective patients prior to plastic surgery procedures, and highlights to clinicians the importance of tailoring information to individual patients.

Adult↗
PubMed2005

Exenterative pelvic surgery--eleven year experience of the Swansea Pelvic Oncology Group.

AIMS: To review indications for surgery and outcomes of patients with complex locally advanced pelvic malignancies treated by a multidisciplinary Pelvic Oncology Group. PATIENTS AND METHODS: Between March 1992 and March 2003, 130 patients were jointly assessed in a monthly clinic involving urological, gynaecological, colorectal and plastic surgeons, an oncologist and nurse specialists. Seventy-six patients proceeded to exenterative surgery. RESULTS: Rectal carcinoma and gynaecological cancers were the two most common indications for surgery. Median follow-up was 14 months (range 1-120 months). There were no deaths within 30 days of surgery. The morbidity rate was 28%. Predicted 5 years survival was 53% in cases with clear histological margins and no lymph node metastasis. CONCLUSION: With careful patient selection and multi specialty care pelvic exenteration is a safe and effective option in the treatment of complex locally advanced pelvic malignancy.

Adult↗
PubMed2002

Severe panniculitis caused by homozygous ZZ alpha1-antitrypsin deficiency treated successfully with human purified enzyme (Prolastin).

Severe panniculitis caused by alpha1-antitrypsin deficiency is very rare even though the ZZ phenotype occurs in 1 : 3500 of the population of northern Europe. We describe a 33-year-old woman with rapidly progressing panniculitis and extensive skin necrosis with multiple life-threatening complications. Initial treatment followed by maintenance therapy with human purified enzyme (Prolastin, Bayer, Bridgend, U.K.) has been life-saving.

Adult↗
PubMed2001

The effects of temperature and time on thermal bond strength in tendons.

Flexor tendon injuries are a common problem requiring sutured repair followed by early postoperative mobilisation. Results are better if active rather than passive flexion is allowed, however active movement increases the incidence of dehiscence. This has prompted examination of thermal bonding as a strategy for strengthening tendon repairs. Three experiments are described, using method and experimental design similar to those previously described. The strength of thermal bonds created between sections of bovine Achilles tendon at a range of temperatures and times was measured. Bonds were created by heating compressed sections in a water bath. Bond strength was measured on a tensiometer as load (N) and stress (N/mm2 and N m kg-1) then calculated using measured cross-sectional area, weight and length. Results were in broad agreement with those previously described, showing peak bond strength in samples heated to 62 degrees C for 8 min (median 17.11 N/cm2, SD 2.13). The effects of cooling to 0 degree C for 10 min immediately after bonding was to increase median bond strength when compared with non-cooled samples bonded under similar conditions (non-cooled, 9.11 N/cm2, SD 3.11; cooled, 11.96 N/cm2, SD 2.93). Statistical analysis using a quadratic regression model showed a close correlation between experimental data and curves modelled to best fit the data. Peak values for thermal bonds created using the methods described approached and in some cases exceeded that reported for the epitendinous element of modified Kessler tendon repairs in human digital flexor tendons. If such bonds could be created in vivo, thermal bonding may have a role in augmenting the strength of tendon repairs. The methods described are impractical for a non-laboratory environment. A laser would seem the most attractive alternative source of heat energy.

Achilles Tendon↗
PubMed2001

Preservation of denervated muscle form and function by clenbuterol in a rat model of peripheral nerve injury.

The effects of clenbuterol in preserving the form and function of muscle after unilateral sciatic nerve division and epineural repair were investigated in a rat model. The drug (a beta2-adrenoceptor agonist) was administered daily for six weeks by gastric gavage (10 microg/kg body weight), interrupted every 5 days by a 2 day omission of dosing to avoid drug desensitization. Clenbuterol reduced the loss of wet weight, total protein, muscle fibre cross sectional area and (in part) contractile forces in denervated hindlimb muscles, with most effects lasting until reinnervation. The effects were dependent on muscle type, with slow-twitch oxidative muscle (soleus) and mixed-fibre (gastrocnemius) showing greater sensitivity to the drug than fast-twitch muscle (extensor digitorum longus). Anabolic effects on the contralateral innervated muscles tended to be small. The results suggest a potential for the adjuvant use of selective beta -adrenoceptor agonists in the management of peripheral nerve injuries in humans.

Adrenergic beta-Agonists↗
PubMed1997

Determination of radiosensitivity in established and primary squamous cell carcinoma cultures using the micronucleus assay.

In this study, the cytokinesis-block micronucleus assay (CBMN) was used to measure radiosensitivity in three established cell lines (SCC-61, V175 and V134) and 10 primary cell cultures of squamous cell carcinoma (SCC) of the head and neck. Assessment involved optimisation of the assay to determine cytochalasin-B (CB) concentration and sampling time postirradiation. A much closer correlation between dose-response data measured in the clonogenic and micronucleus assays was found when the micronucleus assay was performed under standardised conditions for each cell line (2 micrograms/ml CB: 48 h postirradiation) instead of predetermined optimised assay conditions. This indicates that, for these SCC cell lines, the CBMN assay may be able to predict in vitro radiosensitivity. To be of clinical use in predicting radiosensitivity, the CBMN assay also needs to be evaluated with primary cell cultures. In this study, no relationship between micronucleus frequency at 2 or 6 Gy and patient clinical outcome 12 months following surgery and radiotherapy was seen. Similarly, no association between patient outcome and tumour stage, nodal stage and histology was observed. These CBMN assay data from the primary cell cultures are presently inconclusive as a measure of patient tumour radiosensitivity.

Carcinoma, Squamous Cell↗
PubMed1995

Development of a human biomonitoring assay using buccal mucosa: comparison of smoking-related DNA adducts in mucosa versus biopsies.

The aim of this study was to determine whether buccal mucosa would provide an alternate source of tissue for human biomonitoring. Samples of clinically normal oral biopsies were excised, and buccal mucosa were scraped or brushed from patients while they were undergoing surgery for the excision of intra-oral squamous cell carcinoma. Extracted DNA was 32P-postlabeled using the butanol enhancement method, and DNA adduct levels were quantified to compare the accuracy of adduct detection in buccal mucosa versus oral biopsies. For both tissues, tobacco smokers were found to have statistically significant higher levels of DNA damage than samples obtained from nonsmokers (P < 0.001). Mean relative adduct labeling in smokers was very similar for oral biopsies (6.16 x 10(-7)) and buccal mucosa (6.73 x 10(-7)). Likewise, mean relative adduct labeling values for nonsmokers were comparable in the two tissues (1.66 x 10(-7) for biopsies and 2.1 x 10(-7) for mucosa). Overall, an excellent correlation (r = 0.79; n = 32) was obtained between adduct levels in biopsies and mucosa for all classes of patient. These data indicate that buccal mucosa provides an additional tissue for monitoring human exposure to environmental genotoxins. The tissue is obtained rapidly in a noninvasive fashion when harvested by brushing. It can clearly be used to study components in cigarette smoke which cause DNA damage, and it is on the major route of exposure to many environmental genotoxins.

Autoradiography↗
PubMed1995

Post-irradiation changes in the blood vessels of the adult human mandible.

Changes in the inferior alveolar artery and periosteal vessels of the post-irradiation mandible have been investigated. The inferior alveolar artery underwent comparatively little change, stenosis being noted in just over half the specimens examined. The number of periosteal arteries and veins increased, the changes being most marked on the body where the effective tissue dose of radiation was highest. The increase in periosteal vessels was independent of stenosis of the inferior alveolar artery.

Aged↗
PubMed1995

Determination of radiation-induced damage in lymphocytes using the micronucleus and microgel electrophoresis 'Comet' assays.

DNA damage assays may be useful as rapid predictors of normal tissue radiosensitivity in clinical samples. We measured in vitro radiation-induced (2 Gy) damage to lymphocytes from cancer patients and normal healthy donors using both the micronucleus and microgel electrophoresis (Comet) assays simultaneously. For damage assessment, there was a good correlation (P < 0.001) between the mean comet lengths and the fraction of cells with comets. There was no correlation with initial damage, determined as the proportion of cells within a sample that formed comets, in comparison with the mean frequency of micronuclei per binucleate cell. However, there appeared to be an association between the determination of repair proficiency in the Comet assay and the mean frequency of micronuclei per binucleate cell in lymphocytes from cancer patients.

DNA↗
PubMed1993

Detection of DNA adducts in human oral tissue: correlation of adduct levels with tobacco smoking and differential enhancement of adducts using the butanol extraction and nuclease P1 versions of 32P postlabeling.

Samples of clinically normal oral tissue were obtained from patients undergoing surgery for intraoral squamous cell carcinoma. DNA was extracted from samples obtained from 20 tobacco smokers, four exsmokers, and nine nonsmokers and analyzed for the presence of aromatic DNA adducts using two distinct modifications of the 32P postlabeling assay. 32P postlabeling following butanol extraction enhancement revealed a much wider range and substantially higher levels of DNA adducts than obtained following nuclease P1 enrichment. Adduct levels in smokers, exsmokers, and nonsmokers were 1133 +/- 354, 785 +/- 251, and 660 +/- 317 amol/microgram of DNA (+/- SD), respectively. The elevation of adduct levels in smokers compared with either nonsmokers or non- and exsmokers combined is statistically significant (P < 0.005). These observations are consistent with epidemiological evidence linking tobacco smoking with oral cancer. The differential enhancement of DNA adducts with the two 32P postlabeling protocols indicate that aromatic amines and nitroaromatics may be important sources of the DNA adducts detected in human oral tissue.

Adolescent↗
PubMed1993

32P-postlabelling analysis of human tissues and its potential use for biomonitoring.

Samples of clinically normal oral tissue were obtained from 17 tobacco smokers and 7 non- or ex-smokers undergoing surgery for intra-oral squamous cell carcinoma. Isolated DNA was analysed for the presence of aromatic DNA adducts using the 32P-postlabelling technique with adduct enhancement by either butanol extraction or nuclease P1 enrichment. DNA adduction detected following butanol extraction was more diverse and at a higher level than obtained with the P1 method. Adduct levels in the smokers and non- or ex-smokers were 1163 +/- 375 and 774 +/- 318 amol/micrograms, respectively. This difference is statistically significant (p < 0.05). The differential enhancement of adducts with the two protocols suggested that arylamines may be the source of at least a proportion of the DNA adduction detected. These data indicate that oral tissues are likely to be a suitable source of material for human biomonitoring and furthermore they highlight the importance of utilizing more than one enhancement procedure when examining DNA adduction induced by complex mixtures such as tobacco smoke or those encountered at industrial plants.

Butanols↗
PubMed1992

The angiosome--an in vivo study by fluorescein angiography.

Intra-arterial fluorescein has been used to study the area of abdominal skin perfused by the inferior epigastric artery. Three patterns of perfusion were demonstrated and, overall, there was little correlation with the distribution anticipated on the basis of previous cadaver injection studies. It is suggested that the "angiosome" concept proposed by Taylor and Palmer (1987) is of relevance to flap design rather than to the distribution of blood in vivo.

Abdominal Muscles↗
PubMed1989

Age changes in the human inferior alveolar artery--a histological study.

The inferior alveolar artery was examined histologically in non-irradiated surgically resected mandibles. A total of 39 edentulous and 11 partially dentate specimens was studied. Narrowing of the lumen was most commonly due to arteriosclerosis which confirms previous reports. Stenosis was not found to be either commoner or more severe than that recorded in other arteries in the body. It is suggested that apparent narrowing of the inferior alveolar artery seen on angiography may represent a form of involutional atrophy of the artery associated with dental extraction and progressive resorption of the residual occlusal alveolar ridge.

Adult↗
PubMed1988

Recurrent pleomorphic salivary adenoma--the relevance of age at first presentation.

All cases of pleomorphic salivary adenoma treated at the West of Scotland Regional Plastic and Oral Surgery Unit, Canniesburn Hospital, over the 10-year period 1974-1983 have been reviewed. Nearly one-fifth of patients were treated for recurrence. These patients presented with their primary tumour at a significantly younger age (p less than 0.001) than those who remained disease-free. Sixteen of 31 who subsequently developed recurrence were under 30 years of age at initial presentation. Of all patients under 30 years of age at first presentation, 42% subsequently developed recurrent diseases.

Adenoma, Pleomorphic↗
PubMed1987

The free radial forearm flap--the management of the secondary defect.

The secondary defect of the radial forearm flap is usually reconstructed with a split skin graft. This is applied to the visceral paratenon of several tendons in addition to muscle but early movement of the hand is often followed by breakdown, infection, delayed healing and reduced function. A technique for obtaining both full primary healing and full function is described which has produced good results in 16 patients.

Forearm↗
PubMed1987

Intra-oral squamous cell carcinoma in patients under 40 years of age. A report of 13 cases and review of the literature.

The results of the treatment of 13 patients under the age of 40 presenting with primary intra-oral squamous cell carcinoma have been presented. 31% (four patients) survived 3 years from first presentation and all patients who died had recurrent disease within 12 months of surgery. These figures suggest that younger patients with intra-oral cancer have a prognosis similar to an older, more typical cohort.

Adult↗