PubMed Health⌕ Search

Biomedical subjects

D W Cotton

Publications and source records attributed to D W Cotton.

At least 19 recordsLinked to original sources
PubMed1992

The fractal dimension may be a useful morphometric discriminant in histopathology.

The hypothesis is presented that fractal geometry, and the fractal dimension in particular, is likely to be a more useful method of image analysis in histopathology than the use of regular Euclidean geometry. The concept of the fractal dimension is described and it is suggested that many human tumours have a fractal structure over a wide range of scales. It is postulated that the fractal dimension will be useful in discriminating between different diagnostic categories and may also allow more precise prognostic stratification within single diagnostic groups.

Humans↗
PubMed1992

On the origins of mitosis and why it is involved in cancer.

It is suggested that mitosis arose in evolution as a mechanism for 'excreting' damaged DNA (mutations). The mechanism for excretion involved replication of the DNA and was thus a pre-adaptation that could be used for cell replication. In multicellular organisms the mutated cells cannot always be lost and may persist as neoplasms.

Animals↗
PubMed1992

Tubular apocrine adenoma and papillary eccrine adenoma. Entities or unity?

A case of a tubulopapillary hidradenoma was studied by light and electron microscopy and by immunohistochemistry. The tumor, the first reported from the axilla, demonstrated both eccrine and apocrine differentiation and may have arisen from the recently described apoeccrine gland located at this site.

Adenoma↗
PubMed1992

Factors which influence necropsy requests: a psychological approach.

AIMS: To determine which factors influence a clinician's decision to request a necropsy. METHODS: Patient age, confidence in premortem diagnosis, relatives' attitudes, and conditions of necropsy practice were combined factorially (two levels each) in separate medical and surgical questionnaires based on clinical case histories. The interactions between the factors were measured by a repeated measures factorial analysis of variance for each of the two clinical groups. The influence of the clinician's interest in necropsies on these interactions was also examined by a similar method. RESULTS: Necropsies were more likely to be requested on young patients, when diagnostic confidence was low, and when relatives' attitudes were favourable. Conditions of necropsy practice did not affect the likelihood of a request and there was no apparent overall difference in necropsy requests between the two groups of clinicians. The "patient age" and "relatives" factors had less influence on the decision of the surgical group to request necropsy. This was attributed to the opportunity to "see for themselves" at operation and was supported by the finding that surgeons were very likely to request necropsies in the absence of surgical intervention. Clinicians from both groups with a high pre-existing interest in the necropsy were consistently more likely to request necropsies. CONCLUSIONS: The "case history" based questionnaires successfully measured the relative influence of multiple factors in relation to the decision of clinicians to request a necropsy. These findings suggest that any attempt to reverse the decline in necropsy rates should focus on changing the clinician's perception of the value of the modern necropsy.

Age Factors↗
PubMed1991

Computer-assisted image analysis of skin surface replicas.

Using a rubber-based dental impression material, negative surface impressions were made of demarcated areas of skin and prepared as dry specimens for scanning-electron microscopy. Electron micrographs were taken at low magnification and, using a programmed computer-assisted image analyser, it was possible to represent quantitatively the topography of that particular body site according to the degree of circularity of the various geometric subunits. This technique was most applicable to skin topography with a reliable geometrical pattern of triangles and squares, a feature of hair-bearing surfaces in general and in particular, the antecubital fossa. Using standardized trauma of various types the origin of skin surface markings were found to be located in the dermis. The technique was applied to the healing of experimental trauma produced by tape stripping, the resolution of clinical eczema and a comparison of steroid-treated and untreated tape-stripped skin.

Eczema↗
PubMed1991

Assessment of osteopenia at autopsy.

Osteoporosis is a common problem for the pathologist in the elderly female population where pathological fractures particularly of the neck of femur are frequent. Yet how should we assess osteoporosis at autopsy? This study reports on autopsy assessment of osteopenia, comparing our subjective findings of rib fracturability and vertebral compressibility with histological and histomorphometric assessment on a bone biopsy. We have shown a poor correlation between gross autopsy and histological techniques. There is good correlation between two gross autopsy techniques and these methods have been shown to be reproducible between observers. We believe that the most useful test of whether a patient's bones are likely to break is to assess the fracturability of the ribs (and possibly the vertebral bodies) at autopsy. This should be supplemented with undecalcified histology sections from the iliac crest where possible. Further studies are clearly warranted in this area.

Aged↗
PubMed1991

Assessment of osteoporosis at autopsy: mechanical methods compared to radiological and histological techniques.

Osteoporosis is a common problem in the elderly female population and pathological fractures are a frequent complication, but how should the pathologist assess the severity of the disease at autopsy? In this study we have compared subjective, semi-quantitative assessments of rib fracturability, vertebral compressibility, Singh index and histomorphometric methods against a 'gold standard' assessment, namely the force required to fracture the femoral neck. We have shown good correlations between rib fracturability. Singh index and the standard chosen. Poor correlation was shown between histomorphometric techniques and the standard. Our findings suggest that gross rib fracturability is a good indicator of osteoporosis in as far as bone fragility is an indicator of the severity of osteoporosis. However, as the population under examination was small, further studies in this area are clearly warranted in order to extend these findings.

Aged↗
PubMed1990

Factor XIIIa in nodular malignant melanoma and Spitz naevi.

The distribution of factor XIIIa-positive dermal dendritic cells was studied in a series of nodular malignant melanomas and compared with that seen in Spitz naevi. Two patterns of distribution were recognizable: (a) diffusely spread through the tumour and (b) located mainly at the periphery of the tumour. These did not correlate with the diagnosis of melanoma or Spitz naevus and the distribution appeared to be a function of growth pattern of the tumour. The diffuse pattern was the most common regardless of diagnosis and the distribution of factor XIIIa-positive cells is the same in malignant melanoma and Spitz naevi.

Dendritic Cells↗
PubMed1990

Oncocytomas.

Explore the source record for details and available documents.

Adenoma↗
PubMed1990

AgNORs in benign, dysplastic, and malignant melanocytic skin lesions.

Nucleolar organizer regions (NORs) are loops of DNA situated on the short arms of acrocentric chromosomes 13, 14, 15, 21, and 22; they can be demonstrated in formalin-fixed paraffin-embedded sections by a one-step silver technique, the resulting black structures being termed AgNORs. We have applied the technique to 30 benign "banal" nevi (BN), 30 dysplastic nevi (DN), and 30 malignant melanomas (MM). AgNORs in 200 nuclei were scored and the means calculated. Counts were as follows: BN showed a mean of 1.3 AgNORs per nucleus within a range of 1.1-1.6; DN showed a mean of 1.2 within a range of 1.0-1.6; and MM showed a mean of 2.1 within a range of 1.2-4.2. A significant difference existed between counts for MM and those for BN and DN, despite some overlap. There was no statistically significant difference between BN and DN. Although still within the field of research, the AgNOR technique may prove to be of value in helping to differentiate MM from DN, but is unlikely to be of help in separating DN from BN.

Cell Nucleus↗
PubMed1989

Nucleolar organizer regions in Spitz nevi and malignant melanomas.

Nucleolar organizer regions (NOR) are loops of DNA that transcribe ribosomal RNA; they can be easily identified in formalin fixed paraffin embedded tissue using a silver (Ag) method. It has been suggested that the number of AgNOR per cell can differentiate between benign and malignant melanocytic lesions of skin. We have studied 29 Spitz nevi (SN) and 39 invasive malignant melanomas (MM) by the same silver method. SN showed between 1.0 and 1.6 AgNOR per cell with a mean of 1.2. MM counts ranged from 1.2 to 4.2 with a mean of 2.0. It is concluded that the AgNOR method cannot reliably differentiate SN from MM; however, a count of more than 2.0 AgNOR per cell would favor a diagnosis of MM rather than SN.

Flow Cytometry↗