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Biomedical subjects

M G Cook

Publications and source records attributed to M G Cook.

At least 55 records · Page 3Linked to original sources
PubMed1993

Chemically induced cosmetic alopecia.

Cosmetic causes of scarring alopecia are poorly documented. They include traction alopecia and hot-combing. Recently, another group has presented in the South London area, related to misuse of chemical hair straightening agents. Affected patients are young, female, of Afro-Caribbean origin, and typically display hair loss on the vertex of the scalp. Histology shows a pattern of fibrosis and inflammation characteristic of the physical damage seen with other cosmetic procedures. This histological pattern is distinguishable from other non-cosmetic causes of scarring alopecia.

Adult↗
PubMed1993

Annular vasculitis associated with pregnancy.

A 29-year-old woman presented in the 31st week of pregnancy with an unusual bilateral, erythematous eruption on the posterior calves, which clinically resembled erythema annulare centrifugum. A biopsy showed features of a mild leucocytoclastic vasculitis. Within 2 days of delivery the rash had almost resolved, suggesting that its activity was related to the pregnancy. The diagnosis is consistent with 'annular vasculitis', which we suggest represents a distinct variant of leucocytoclastic vasculitis, and a distinct clinicopathological entity. We are not aware of any previous reports of an association between annular vasculitis and pregnancy.

Adult↗
PubMed1993

Are pigmented lesion clinics worthwhile?

To assess the effect of a pigmented lesion clinic on referral patterns and thickness of melanoma at presentation, we have compared data from the centralized pathology services of the adjacent health authorities of Wandsworth, and Merton and Sutton. Both districts were the subject of a CRC public awareness campaign in 1987, but only Wandsworth is served by a pigmented lesion clinic. All patients presenting with malignant melanoma were included; from 1981 to 1990 for Wandsworth, and from 1984 to 1990 for Merton and Sutton. The Breslow thickness and clinic source of all melanomas was documented. Approximately equal numbers of melanomas were seen in the two districts, with no obvious difference in the numbers of thin (< 1.5 mm thick) 'good prognosis' tumours. Both districts saw an increase in the total number of tumours, and the number of thin tumours, after the CRC publicity campaign. However, there was considerable cross-boundary referral to the pigmented lesion clinic in Wandsworth, with 60% of all melanomas coming from outside the district. The presence of a pigmented lesion clinic within a given district confers no obvious benefit with regard to the number of thin, 'good prognosis' melanomas being seen as a whole, but the cross-boundary referral pattern suggests that it fulfils a demand from both general practitioners (GPs) and patients, and it does provide a centralized source for the collection of much-needed data.

Health Education↗
PubMed1993

Fatal facial ulceration.

A case of an elderly man with a large facial ulcer is reported. The diagnosis of Wegener's granulomatosis was made at post-mortem when evidence of a granulomatous vasculitis was found in both the skin and lungs. This case serves to illustrate the difficulty in making the diagnosis of Wegener's granulomatosis, especially when it presents in its 'limited' form.

Aged↗
PubMed1993

Primary malignant melanoma of the rectum.

The diagnosis of a primary rectal malignant melanoma has been the subject of considerable argument for many years, principally on the grounds that extension from a primary anal lesion was often impossible to exclude. This paper provides evidence that certain melanomas can be recognized as primary rectal tumours, not only from careful anatomical assessment of the site of the tumour, but also by showing that they arise on a background of benign melanocytic proliferation in the rectal mucosa. The clinical presentation of these lesions, their possible mechanism of origin and their treatment is discussed.

Aged↗
PubMed1993

Catecholamines modulate protein turnover in cultured, quiescent rabbit cardiac myocytes.

When rabbit ventricular myocytes were cultured for 1 wk and then exposed to alpha- and/or beta-adrenergic agonists, such nonbeating heart cell preparations disclosed increased protein-to-DNA ratios and elevated RNA content, indicative of cellular hypertrophy. Norepinephrine, isoproterenol, and phenylephrine provoked hypertrophy with norepinephrine eliciting a greater response than isoproterenol or phenylephrine. Specific alpha- and beta-antagonists blocked growth by inhibiting catecholamine-induced changes in protein turnover. Each catecholamine enhanced the fractional rate of protein synthesis within 48 h; however, changes in growth rates appeared to be modulated, in part, by alterations in protein degradation. Even though rates of total protein and actin synthesis resembled values measured in vivo, myosin heavy chain fractional rate of synthesis was only 22% of in vivo levels. Double label immunofluorescence microscopy further illustrated that catecholamine treatment accelerated myofibrillar disruption in these quiescent heart cells. These observations suggested that in the absence of beating, neurohumoral modulation of contractile protein turnover was not associated with the maintenance of myofibrillar integrity even though catecholamines induced cellular hypertrophy.

Animals↗
PubMed1992

Oral contraceptives and risk of benign proliferative epithelial disorders of the breast.

In a case-control study conducted in Adelaide, South Australia, we investigated the hypothesis that use of oral contraceptives is associated with increased risk of benign proliferative epithelial disorders (BPED) of the breast, conditions strongly associated with increased risk of breast cancer and thought to have pre-malignant potential. The study was restricted to women with no prior history of breast biopsy, and involved 383 cases of biopsy-confirmed BPED, 192 controls whose biopsy did not show epithelial proliferation, and 383 unbiopsied community controls individually matched to cases by age and socio-economic grading of area of residence. When cases were compared with community controls, the adjusted odds ratio (OR) for the association between ever-use of oral contraceptives and risk of BPED was 1.1 (95% CI 0.7 to 1.7), while when cases were compared with biopsy controls, the adjusted OR was 0.9 (95% CI 0.5 to 1.5). There was little variation in risk of BPED with total duration of use of oral contraceptives, and with duration of use before first pregnancy, while current users had a statistically significant 60% reduction in risk, irrespective of the control group used for comparative purposes. Also, there was little variation in risk with years since first and last use of oral contraceptives, and there was no trend in the association between ever-use of oral contraceptives and risk of BPED by degree of cytological atypia.

Adult↗
PubMed1992

Risk factors for fibroadenoma: a case-control study in Australia.

Risk factors for fibroadenoma were examined in a case-control study involving 117 fibroadenoma cases ascertained by a major private pathology laboratory in Adelaide, Australia, between January 1983 and October 1985. For each case a population control was randomly selected from the electoral roll in Adelaide and matched to the corresponding case by sex, age, and socioeconomic grading of area of residence. Another 189 women whose first biopsy for benign breast disease was examined in the same laboratory during the same time period as those of the cases, but did not show evidence of epithelial proliferation, were also included in the study as a biopsy control group. Risk of fibroadenoma was associated inversely with the Quetelet index, but there was no evidence of an association with age at menarche or menopausal status. The risk of fibroadenoma decreased with an increasing number of full-term pregnancies and was increased in association with use of oral contraceptives at an early age (under 20 years); however, these two associations were observed only when cases were compared with the population controls. Alcohol consumption and dietary fat intake were found not to be associated with altered risk of fibroadenoma, while in multivariate analyses, duration of cigarette smoking and daily vitamin C intake were both shown to have inverse associations with risk of fibroadenoma. Although fibroadenoma does share some risk factors with breast cancer, there is insufficient evidence to suggest that it represents a precursor state.

Adenofibroma↗
PubMed1992

Granular cell tumour of the breast.

Eight cases of benign granular cell tumour of the breast are reported. Seven patients were women and one was male. The age at the time of the excision ranged from 17 to 73 (average 40.1) years. All tumours were positive for S-100 protein and negative for keratin, myoglobin and gross cystic disease fluid protein. In two cases ultrastructural studies revealed findings identical to those in the previously reported cases of granular cell tumours. None of these cases were diagnosed preoperatively. In six cases the clinical and mammographic findings, and in one case the frozen section, led to an erroneous diagnosis of malignancy. The clinico-pathological features of the cases are delineated in order to draw attention to a benign condition which closely simulates malignancy.

Adult↗
PubMed1992

Re-excisions of scar in primary cutaneous melanoma: a histopathological study.

In many centres the wide excision and split-skin grafting remains the standard therapy for primary cutaneous melanoma. One-hundred and thirty-seven primary cutaneous melanomas were seen in our department during a 3-year period; 25 patients were subsequently subjected to re-excision of scar following the initial excision biopsy. Lymphatic permeation, field change in the epidermal melanocytes and micrometastases were sought in the re-excision specimens in order to examine the pathological basis for this therapy. Two of the 25 primary melanomas included in this study were known to have been incompletely excised at the time of initial biopsy and both re-excision specimens included a few nests of atypical melanocytes adjacent to one edge of the biopsy wound. Examination of the re-excision specimens failed to demonstrate evidence of direct lymphatic permeation by melanoma, or of a field change in the epidermal melanocytes adjacent to the melanomas, although five specimens from sun-exposed sites showed slight melanocyte atypia. One re-excision specimen did include a single small group of melanocytes, less than 120 microns in size, in the dermis within 2 mm of the initial excision biopsy site of a melanoma 8.4 mm in thickness. These results support the view that more extensive local therapy than complete excision of primary cutaneous melanoma with a narrow margin of adjacent normal skin, is unlikely to benefit the patient.

Cicatrix↗
PubMed1992

Pagetoid infiltration in primary cutaneous melanoma.

Pagetoid infiltration of the epidermis by melanocytes, also termed 'buckshot spread', is regarded by some as being essential for the confident histopathological diagnosis of primary cutaneous melanoma. We have reviewed 340 melanomas received over a 23 year period to assess the frequency of pagetoid infiltration and whether its presence bears any relationship with other histopathological features. Conspicuous pagetoid infiltration was present in 32.1% of the lesions and occasional melanocytes were observed within the stratum spinosum in a further 23.5% of cases. However, no melanocytes could be seen above the basal layer in 44.4% of the melanomas. The presence of pagetoid infiltration showed inverse correlation with tumour thickness, level of invasion, growth phase and mitotic count, and positive correlation with the presence and severity of regression. No association was found with the site of the primary lesion, melanocytic dysplasia or lentigo maligna in the adjacent epidermis, or with the presence of residual benign naevus cells in the epidermis. Thus, pagetoid infiltration of the epidermis was commonest in in situ or thin horizontal growth phase melanomas, and was conspicuous in only one-third of cases. While its presence is useful in the diagnosis of melanoma, its absence should not preclude it.

Humans↗
PubMed1991

The vascularity of primary cutaneous melanoma.

In primary cutaneous malignant melanoma, the vascularity of the dermis immediately deep to the lesion may relate to tumour aggressiveness and to prognosis. These newly formed dermal vessels are incorporated into the melanoma to form the tumour microcirculation. We have assessed the percentage vascular volume in a series of primary melanomas in order to investigate the relationship between tumour vascularity and maximum tumour thickness. For the 64 melanomas included in this study, there appeared to be a significant relationship between the percentage vascular volume and the maximum tumour thickness. This relationship was not influenced by the presence of necrosis, vascular invasion, regression, or lymphocytic infiltrate, nor by the growth phase of the tumour. However, the percentage vascular volume was very low in the occasional thick melanoma, at least one of which was associated with prolonged survival. It seems possible that a low tumour vascularity could correlate with a relatively favourable outcome in cutaneous melanoma.

Humans↗
PubMed1991

Cell shape and organization of the contractile apparatus in cultured adult cardiac myocytes.

The isolation and culture of adult cardiac myocytes has proved to be an ideal model system to explore myocardial biology at the cellular level. A major criticism of this model, however, has been that organ-specific characteristics such as cell shape and subcellular structural organization cannot be retained in vitro for prolonged periods of time. Encasing freshly isolated myocytes in a matrix of calcium alginate enables one to maintain the rod-like, three-dimensional (3D) shape of the cultured myocyte. Such preparations more closely resemble their in vivo counterparts with respect to the organization of the contractile apparatus, the transverse tubular system and the sarcoplasmic reticulum than do heart cells cultured on a two-dimensional (2D) plastic surface. Stereologic measurements reveal that myofibrillar volume density (VvMYF) decreases in both non-beating preparations over a 2-week interval, but VvMYF is conserved in cells cultured in an alginate matrix when compared to those myocytes maintained on a laminin-coated substratum. The present observations suggest that in the absence of contractile function myofibrillar atrophy appears responsible for the decline in VvMYF in alginate (3D) preparations, whereas atrophy and subcellular remodelling probably mediate the myofibrillar loss and reorganization that develops when adult heart cells are cultured on a 2D surface.

Alginates↗
PubMed1991

Comparison of liver histology with ultrasonography in assessing diffuse parenchymal liver disease.

To establish the accuracy of ultrasonography in assessing diffuse parenchymal liver disease we performed a prospective comparative study with histology in 50 patients with a wide range of liver disease. Liver biopsy was performed within 24 h of the ultrasound examination and ultrasonography was performed by a single operator who was unaware of clinical details of the patients. Histology was reviewed blind and the degree of steatosis graded mild, moderate or severe while increased portal fibrous tissue was graded mild, moderate or established cirrhosis. Thirty-six patients had steatosis and 31 patients had increased fibrous tissue on histology. Ultrasonography correctly identified steatosis in 32/36 (89%) patients including all patients with the severe grade. Increased fibrous tissue was correctly identified in 24/31 (77%) with a sensitivity of 100% in patients with moderate fibrosis and established cirrhosis. Specificity was 93% for steatosis and 89% for increased fibrous tissue. These results show that ultrasonography can provide a non-invasive prediction of liver histology which in moderate and severe steatosis and advanced fibrosis can be both highly sensitive and specific.

Biopsy, Needle↗
PubMed1991

Ultrasonic patterns in inflammatory bowel disease.

Ultrasound examination was performed in 90 patients with varying bowel pathology. Ultrasound reliably demonstrated thickening of the bowel. In addition, the pattern of abnormality seen in Crohn's disease and ulcerative colitis was different, and corresponded to the pathological changes seen in these disease processes. The pattern of bowel abnormality seen in other bowel diseases with an inflammatory aetiology generally corresponded to either the Crohn's or ulcerative colitic pattern. The appearances are described, together with findings in other non-neoplastic diseases of the bowel.

Colitis, Ulcerative↗
PubMed1991

Melanocytic lesions and melanocyte populations in human epidermis.

Basal melanocytes were counted and atypia assessed on an arbitrary scale in punch biopsies from the sun-exposed extensor aspect of the forearm of normal skin and from the covered skin of the buttock of patients with pigmented naevi and control subjects. The difference in melanocyte counts and in the presence of atypia between sun-exposed and covered skin was statistically highly significant. The only other difference was between melanocyte counts in covered skin from those with multiple atypical naevi and all other groups; the counts in the former were greater than those in the latter. No further difference was attributable to sun exposure, skin type or diagnostic group. Some degree of melanocyte atypia was seen in approximately half of the biopsies of sun-exposed skin, but atypia was seen in only six of 84 biopsies of covered skin. In each case atypia was present in the corresponding forearm biopsy and all six subjects had pigmented lesions (four with melanoma and two with multiple atypical naevi). It seems possible that while increased melanocyte counts in covered skin could correlate with the presence of atypical naevi, atypia of covered epidermal melanocytes could possibly relate to melanoma risk.

Adult↗