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Biomedical subjects

A G Cowie

Publications and source records attributed to A G Cowie.

At least 19 recordsLinked to original sources
PubMed1996

31P NMR studies of human skin using a modified zig-zag surface coil.

Results are presented from an in vivo study of human skin in which a zig-zag surface coil together with a three-pulse Fourier Series Window (FSW) protocol have been used to obtain minimally contaminated 31P skin spectra of the posterior calf. Phantom experiments indicate that while the fall-off in the B1 field profile of the zig-zag surface coil is superior to conventional surface coil designs, it is still not sufficient on its own to reduce muscle signal contamination to acceptable levels in human studies. The additional spatial localization required is provided by the FSW, which reduces signal contamination to less than 30% of the total signal collected. In a study of 18 normal controls the measured pH was found to be relatively high (7.39 +/- 0.08), while the ratios of skin PCr/ beta-ATP (1.04 +/- 0.35) and PCr/Pi (1.67 +/- 0.4) were found to be low compared with that of skeletal muscle. In addition, substantial signal from phosphomonoesters and phosphodiesters were also observed.

Adenosine Triphosphate↗
PubMed1996

Use of the Fourier series window protocol with a zig-zag surface coil in 31P NMR human skin spectroscopy. A theoretical study.

The use of a zig-zag surface coil with a three-pulse Fourier Series Window (FSW) has been suggested as a means by which in vivo NMR spectroscopic studies of human skin can be performed. Using direct numerical simulations of the magnetic field profile of a 10 limb zig-zag surface coil, the role of the FSW in reducing NMR signals originating from the deeper skeletal muscle layers is examined theoretically. The extent of muscle signal contamination is determined for different coil inter-limb spacings and pulse width settings. The optimum inter-limb spacing for studying living human skin, that which minimizes signal contamination and maximizes skin signal collected, is shown to be between 4 and 6 mm. These calculations demonstrate that the FSW and zig-zag surface coil offer a protocol for investigating the metabolism of large areas of surface tissue while keeping signal contamination from the deeper skeletal muscle layers down to an acceptable level.

Fourier Analysis↗
PubMed1992

Independent evaluation of impotence by colour Doppler imaging and cavernosometry.

Colour Doppler imaging and cavernosometry are the optimal means for objective assessment of pharmacologically induced penile erections. 21 impotent patients were assessed by both methods independent of the information derived from the other modality. The diagnosis obtained was found to be immediately consistent in only 10 cases, 7 of which had venous leakage. 6 of the remaining 11 patients had a diagnosis of mixed arterial and venous disease in one or the other modality, but only arterial or venous disease alone in the other. The remaining 5 patients had completely inconsistent diagnoses. However, knowledge of the clinical picture and awareness of the pitfalls in the diagnostic procedures allows most of the discrepancies to be explained. Colour Doppler imaging is subject to operator error but allows selection of patients for cavernosography.

Erectile Dysfunction↗
PubMed1988

Hyperparathyroidism after neck irradiation.

A retrospective review of 1550 cases of hyperparathyroidism (HPT) treated surgically over a 30-year period reveals a past history of exposure to neck irradiation in 10 cases (0.7 per cent). The indication for radiotherapy was benign disease in nine and papillary thyroid carcinoma in one case. The mean interval between radiation exposure and the detection of HPT was 32 years (range 3-63 years). Patients treated with radioactive iodine alone developed HPT after a mean of 5 years while the interval for those treated with external beam therapy alone was a mean of 44 years. The parathyroid histology was adenoma in six cases, carcinoma in three cases and nodular hyperplasia in one case. All patients had coincident benign thyroid disease apart from one that had previously had papillary carcinoma and another with follicular carcinoma. Neck irradiation has been shown to confer an increased risk of HPT due to parathyroid adenoma and carcinoma. Radiotherapy for benign disease has generally been abandoned and these cases demonstrate a further contra-indication for the use of neck irradiation.

Adult↗
PubMed1987

Kidney mast cells, IgE and release of inflammatory mediators capable of altering renal haemodynamics.

Collagenase-dispersed human, guinea pig and rat kidney cells, actively or passively sensitized with IgE or IgG subclasses, released histamine, leukotriene C4 and thromboxane B2 on challenge with the specific antigen or antisera to mast-cell-sensitizing immunoglobulins. A similar reaction occurred in the isolated perfused kidney of sensitized guinea pigs, which additionally showed vasoconstriction. Mast cells were identified in cell suspensions and tissue sections. These findings provide support for the possible role of IgE and mast cells in renal pathophysiology.

Adult↗
PubMed1983

The radiological appearances of the liver after surgical removal of hydatid cyst.

Simple excision of a hydatid cyst from the liver leaves a residual cavity. Depending upon the surgical management of the cavity this can appear cystic, hypoechoic or echogenic on subsequent ultrasound examination. Negative attenuation values on computed tomography are typical of omentoplasty. These appearances can mimic pathological lesions in the liver. Knowledge of the site and nature of previous surgery can prevent diagnostic confusion.

Adult↗
PubMed1982

Experience with mebendazole in the treatment of inoperable hydatid disease in England.

Eleven heterogeneous patients with inoperable hydatid disease were treated with high doses of oral mebendazole, up to 200 mg/kg/day for 16 to 48 weeks. Toxicity was not encountered. Despite careful assessment it proved difficult critically to evaluate the efficacy of mebendazole. In four patients chemotherapy appeared to have been at least partially successful and success seems to have correlated with serum levels in excess of 100 ng/ml one to three hours after dosage. The problems of assessment are discussed and the need for controlled trials of mebendazole in hydatid disease are stressed.

Adolescent↗
PubMed1982

Morbidity in adult parathyroid surgery.

The results of surgery in a series of 700 consecutive cases of primary and tertiary hyperparathyroidism are reported with especial reference to mortality and morbidity. Providing that the operation is a first or second operation and that the patient is below 70 years of age, the operation has been found to be safe and uncomplicated.

Adolescent↗
PubMed1980

Ectopic parathyroid adenomas.

Two cases of parathyroid tumours occurring in unusual situations are described. Such cases may cause difficulty in both the diagnosis and the surgical treatment of hyperparathyroidism. The cases described illustrate the importance of a definitive aetiological diagnosis in hypercalcaemia, if appropriate surgery is to be performed. The value of discriminant function analysis and hydrocortisone suppression tests are discussed.

Adenoma↗
PubMed1978

Ureteric involvement with abdominal aortic aneurysm.

The clinical presentations of 3 patients found to have an abdominal aortic aneurysm with ureteric involvement have been described. The world literature concerning this problem and methods of surgical treatment have been reviewed. The importance of medial displacement of the ureters as an early diagnostic sign indicating the presence of an abdominal aortic aneurysm is again emphasised. The possibility of a relatively benign course for the aneurysm should be considered in patients with renal or cardiorespiratory complications. In such cases, treatment of the ureteric involvement alone is justified.

Aged↗