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Biomedical subjects

T M MacLeod

Publications and source records attributed to T M MacLeod.

At least 19 recordsLinked to original sources
PubMed2004

An unusual complication of penile piercing: a report and literature review.

Body piercing has been practiced for many centuries and is thought to have its origins in the Hindu religion. As traditional ear piercings have given way to more adventurous anatomical sites, so too have the associated complications of these practices. We present the case of a 35 year old man who presented 12 months after a penile piercing with an extensive fistula of the glans penis resembling an acquired glanular hypospadius.

Adult↗
PubMed2004

Evaluation of a porcine origin acellular dermal matrix and small intestinal submucosa as dermal replacements in preventing secondary skin graft contraction.

The degree to which a split thickness skin graft (STSG) contracts after application to its recipient bed is related in part to the proportion of the dermis harvested from the donor site. Harvesting thicker skin grafts may produce better cosmetic results in the recipient bed but result in increased donor site morbidity. The combination of an autologous ultra thin split thickness graft with an underlying non-autologous dermal component may reduce secondary skin graft contraction without further increasing donor site morbidity. This study was aimed at assessing the suitability of two porcine derived biomaterials (Permacol and small intestinal submucosa, SIS) for use in combination with skin grafts in a Sprague-Dawley rat model. Full thickness wounds (1 cm(2)) were created in Sprague-Dawley rats and grafted with skin in combination with Permacol or SIS either as a one-stage operation or following a 2-week-period of vascularisation of these dermal matrices before a second stage operation to cover with skin. Skin graft viability and wound area were assessed at weekly intervals until 4 weeks after graft application. Both Permacol and SIS were able to support an overlying skin graft but had no beneficial effect on skin graft contraction in this model compared to skin grafts alone.

Animals↗
PubMed2003

Prefabricated skin flaps in a rat model based on a dermal replacement matrix Permacol.

The reconstruction of three-dimensional structures is one of the most challenging problems in plastic surgery. While shaped frameworks incorporated within soft tissue envelopes often lose their fine detail, the integration of a blood supply to a stable biomaterial scaffold allows skin graft cover and emphasis of fine detail. The aim of this study was to evaluate whether a porcine derived isocyanate crosslinked collagen tissue matrix (Permacol) could be vascularised from an isolated vascular pedicle and subsequently sustain an overlying skin graft as a pedicled prefabricated flap. A vascular induction technique was employed using the epigastric pedicles in Sprague-Dawley rats to vascularise 2 x 2 cm(2) pieces of Permacol of standard 0.75 and 1.5 mm thickness Permacol and laser treated Permacol of 0.4 and 0.75 mm thickness. Flaps were able to support overlying skin grafts as early as 2 weeks following vessel implantation and laser treated Permacol had an increased vascularity compared to standard Permacol with no evidence of degradation. The study showed that Permacol could be a useful matrix for use in tissue engineered flaps.

Animals↗
PubMed1990

Filtration as part of the validation and routine testing of a purified water system.

A distillation system, which includes a steam condensate supply, pre-treated before distillation by passage through carbon and mixed resin barrels, is described. Filtration of 5-litre aliquots from a storage tank/ring mains system through a 0.45-micron cellulose filter identified contaminants (rust from the ring mains and carbon from the barrel) which were not detected by the British Pharmacopoeia tests for purified water.

Filtration↗
PubMed1989

HPLC studies on the degradation profiles of glucose 5% solutions subjected to heat sterilization in a microprocessor-controlled autoclave.

A practically useful relationship between degradation and F0 at various temperatures is given. This may be of value for identifying the most suitable sterilization conditions for a number of glucose products and other pharmaceuticals. It was found that autoclaving at a high temperature to a low final F0 value gave the maximum product integrity.

Chromatography, High Pressure Liquid↗
PubMed1989

Polymorphonuclear leucocyte chemotaxis in response to leukotriene B4 in treated and untreated psoriatics.

Various chemoattractants have been implicated in the aetiology of the polymorphonuclear leucocyte (PMN) migration into the epidermis seen in early lesions of psoriasis. Using an under-agarose technique, the in vitro chemotactic responses of PMN to the arachidonic acid lipoxygenase product leukotriene B4 (LTB4) were assayed in five groups of subjects: normal healthy volunteers (n = 12), untreated psoriatics (n = 11) and psoriatics treated with topical tar (n = 12), PUVA (n = 11) and UVB phototherapy (n = 10). No significant difference was observed between the responses of control subjects and of untreated psoriatics, nor between the untreated psoriatic group and the PUVA- and UVB-treated groups, respectively. However, comparison of the tar-treated and untreated groups revealed a significantly increased chemotactic response to LTB4 in the tar-treated group (p less than 0.01).

Chemotaxis, Leukocyte↗
PubMed1985

Drug dilution in anaesthetic practice.

The accuracy of dilution by anaesthetists of commonly used drug preparations was assessed by ultra violet spectrophotometric assay of the diluted drugs. Percentage deviation from target concentrations was then calculated. Of a total of 358 drug dilutions carried out by 28 anaesthetists only 58% were within 10% of the target concentration while 6% lay outside 50% of the target concentration.

Anesthesiology↗
PubMed1981

Cell-mediated immune response to basal cell carcinoma.

The role of cell-mediated immunity in controlling Basal Cell Carcinoma (BCC) growth was studied by measuring the transformation of lymphocytes when challenged in vitro with aqueous extracts of the patients' BCCs and of control skin. Tests were carried out in the presence of autologous and heat-treated plasma. Three patients out of 8 showed significantly raised thymidine uptake ratio (TUR). Heat-treated plasma produced higher TURs, indicating the presence of an inhibitory factor.

Antigens, Neoplasm↗
PubMed1976

Leucocyte aggregation in subjects with nickel dermatitis.

The effect of nickel sulphate on leuco-aggragation in whole blood buffy coat layers was studied in nickel-sensitive and control subjects. At concentrations of 150 mug and 200 mug nickel sulphate per ml a significant increase in the numbers of leuco-aggregates was noted in the nickel sensitive as compared with the control subjects.

Antigens↗
PubMed1976

Leucocyte aggregation and lymphocyte transformation induced by mercuric chloride.

Leuco-aggregation tests carried out on normal subjects using the non-specific mitogen mercuric chloride produced micro-aggregates in the concentration range 2-100 mug/ml with a peaking effect at about 10 mug/ml. These results showed good correlation with lymphocyte transformation test thymidine uptake ratios which were maximal at 2-10 mug/ml.

Dose-Response Relationship, Immunologic↗
PubMed1975

Nickel hypersensitivity. Nickel binding to amino acids and lymphocytes.

The nature of a protein hapten conjugate which could effect lymphocyte transformation in nickel hypersensitivity was investigated by subjecting the culture media employed to radiochromatographic analysis. Autoradiographic studies with 63Ni demonstrate direct binding of nickel salts to the lymphocyte cell surface. This occurs with a proportion of lymphocytes both from nickel sensitive and from control subjects and so binding is not of itself the stimulus for transformation.

Amino Acids↗
PubMedDate not supplied

Bath PUVA--an investigation of the distribution of trioxsalen (TMP) and 8-methoxypsoralen (8-MOP) in bathwater.

Trioxsalen (TMP) bath PUVA avoids the side effects of nausea and headache associated with oral 8-methoxypsoralen (8-MOP) treatment and allows shorter irradiation times that can be advantageous in some patients. However we noted that a number of patients developed unusual patterns of phototoxic burning. We thought that this was related to an uneven distribution of the TMP in the bathwater and for this reason, a study of bath water TMP concentrations achieved using different TMP preparations was undertaken. The distribution of 8-MOP in an 8-MOP bath was also measured for comparison. Our results confirm that an uneven distribution of TMP is achieved using TMP capsules or suspension and would explain our observed patterns of burning. With an ethanolic solution of TMP, or the commercial equivalent Tripsor, or with Puvasoralen-8 (an 8-MOP preparation), a homogeneous psoralen distribution is achieved, and they are therefore preferable for use in bath PUVA.

Administration, Cutaneous↗