A method of classification based on color and morphological differences of the mesocarp is described for determining the developmental stages of fresh peanut [Arachis hypogaea (L) ‘Flo-runner’] pods. Developmental stages are designated as Classes 1-7, with each subsequently numbered class representing progressively greater degrees of maturity. For illustration each class is subdivided into one-quarter increments which are represented pictorially by beginning points. Because various combinations of classes and/or subclasses can be used, the system has inherent flexibility to accomodate the degree of refinement dictated by classification needs. Maturity determination by this method requires removal of a portion of the exocarp or epidermis to expose the pod mesocarp. The exocarp can be removed by sand blasting, gentle abrasion, or lightly scraping with a knife. Because removal of the exocarp is non-destructive to the remaining pod structure and enclosed seeds, the method has inherent advantages for use in commercial culture and in biological investigations requiring intact pods and/or seed.
SYNOPSIS Thirty-one dog thyroid tumours and 28 spontaneous rat thyroid tumours were studied histologically and the findings compared with those of a study of 67 cases of medullary carcinoma of the human thyroid.Five of the dog tumours and 24 of the rat tumours were considered to belong to the same group of tumours as medullary carcinoma, a group characterized by solid sheets or lobules of uniform cells with granular cytoplasm and without papillary or follicular differentiation. In the rat tumours it was shown that the cell of origin was the parafollicular cell and not the thyroid follicle epithelial cell.It is suggested that medullary carcinoma is also derived from a parafollicular cell and that this origin would resolve the discrepancy between the relatively good prognosis and the apparently undifferentiated structure of this tumour. It is also concluded that the whole spectrum of clinical and pathological features of medullary carcinoma makes more sense if it is considered as a parafollicular cell tumour.Medullary carcinoma of the thyroid is a distinct and clearly defined entity, and the histological features of 67 examples are discussed in the previous paper (Williams, Brown, and Doniach, 1966). The survival of patients with this tumour is often prolonged although paradoxically the vast majority of cases show no evidence of differentiation towards a thyroid epithelial pattern. This paradox is based on the assumption that medullary carcinoma of the thyroid is derived from the thyroid follicular epithelial cells; if this were not so then the absence of papillary or follicular structures would not necessarily imply a lack of differentiation. A second type of thyroid epithelial cell, the 'light' or parafollicular cell, is well described in many animals and the concept that medullary carcinoma of the thyroid is a parafollicular cell tumour seemed plausible.
A comparison of the incidence of the different histological types of thyroid carcinoma in an area of high dietary iodide and an area of normal iodide intake has been made. The areas chosen were Iceland and the region of Northeast Scotland centred on Aberdeen; both areas have clearly defined populations served by a single pathology laboratory. All definite and dubious thyroid carcinomas from both regions were examined and classified by the same two pathologists. The age-specific incidence rates for papillary carcinoma in surgical specimens in both areas rose with age; they were five times higher in Iceland (high iodide area) than in Northeast Scotland. The numbers of follicular carcinomas were small, and this tumor was relatively less frequent in Iceland than Aberdeen. These findings, together with the known high relative frequency of follicular carcinoma and low frequency of papillary carcinoma in areas of endemic goitre, lead to the suggestion that the incidence of papillary carcinoma and follicular carcinoma are separately influenced by dietary iodide, papillary carcinoma being high in areas of high iodide intake and low in areas with low dietary iodide. No evidence to implicate lymphocytic thyroiditis, radiation or genetic factors in the genesis of thyroid carcinoma in Iceland or Northeast Scotland was found in this study. Undifferentiated carcinoma was about three times as common in Iceland as in Northeast Scotland. Malignant lymphoma of the thyroid was suprisingly common in Northeast Scotland, possibly related to the high frequency of thyroiditis found in this region. These studies suggest that the incidence of different histological types of thyroid malignancy is influenced by different etiological factors. They also provide support for the subdivision of thyroid malignancy into these different types, and for the general importance of accurate histological typing in cancer epidemiology.
SYNOPSIS The pathological features of 67 cases of medullary carcinoma of the thyroid were studied, and when possible the case histories were reviewed.The typical tumour is sharply demarcated but not encapsulated, is composed of sheets of cells having eosinophilic granular cytoplasm, with the deposition of amyloid in the stroma. We would stress the frequency of binucleate cells, the scarcity of mitoses, and the frequent occurrence of calcification.The clinical findings show a wide variation in age at presentation of this tumour, and a wide variation in prognosis, with a mean survival from the time of presentation to hospital of 6-6 years, the longest being 21 years. Two of this group of patients also had phaeochromocytomas; these two and three others showed small papillary tumours of the eyelids, lips, and tongue.Despite the variation in some of its characteristics, medullary carcinoma of the thyroid is considered to be a distinct and sharply defined entity. It appears to be the only type of thyroid carcinoma associated with phaeochromocytoma, the only type associated with multiple mucosal neuromas and the only type with a familial incidence. These findings emphasize the validity of its separation from other types of thyroid carcinoma. 885 cases of thyroid carcinoma. These authors referred to the tumour as 'solid carcinoma with amyloid stroma' rather than medullary carcinoma. Because of the prognostic importance of recognizing this type of tumour histologically and because a number of cases with unusual associated diseases came to our attention, we decided to analyse the histological features of a large series of medullary carcinoma of the thyroid and study the available clinical records and follow-up.Sixty-seven examples of medullary carcinoma of the thyroid were studied histologically. Twenty-two were from the London Hospital; the rest were obtained from the files of four other London hospitals and from a number of individual pathologists who kindly sent in material. A major criterion for the inclusion of a case within the series was the presence of amyloid in the stroma of the tumour. In the great majority of cases amyloid was identified by at least two of the three generally used histological techniques for this substance, methyl violet, congo red, and thioflavin T. In two cases thioflavin T alone gave a positive result. In four cases only sections stained with haemalum and eosin were available; in these amyloid was identified by its amorphous 103 on 10 May 2018 by guest. Protected by copyright.
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