histamine: pathological tissues 



to which they contain mast cells. Thus, the enlarged lymph node was virtually 

 replaced by mast cells; many mast cells were present in the enlarged spleen 

 and there was some increase in mast cells in the portal tracts of the liver. On 

 the other hand, very little increase in mast-cell content was found in the lung, 

 and none in kidney or in skin taken from the flank remote from the primary 

 growth. 



Thanks to the continued co-operation of Mr. K. W. Head, ten further 

 specimens from dogs with mast-cell tumours have been obtained for study. 

 All support the conclusions previously reached, that the mast cell in the dog 

 is as rich in histamine as it is rich in heparin (Table IX, p. 86). It is of interest 

 to record in passing that portions of two other subcutaneous tumours from 

 dogs which were sent to us pending histological diagnosis were found to have 

 very low histamine values (only 2-1 and IT (j.g. g. tissue respectively) and to 

 contain no detectable heparin : the first proved to be a fibroma, the second a 

 squamous carcinoma. This further confirms the view that it is the mast cell 

 which contains both the heparin and the histamine. 



Of the ten dogs with mastocytoma recorded in Table IX no less than five 

 had ultimately to be destroyed either on account of local recurrence or distant 

 metastases. The findings are recorded in Table X (p. 86). 



Examination of Tables VIII-X (pages 85-86) clearly indicates that so far 

 as the dog is concerned, a raised mast-cell content in a tissue is invariably 

 accompanied by a parallel increase in both tissue histamine and tissue heparin. 



Cats. Mast-cell tumours in cats are decidedly less common than mast-cell 

 tumours in dogs. In their original description of a mast-cell tumour in a cat, 

 Sabrazes and co-workers (1908) recorded a case in which a pigmented tumour 

 was situated on the eyelid and was thought to be a melanoma. However, at 

 autopsy the spleen was found to be enlarged and studded with masses of mast 

 cells which appeared to be arising from large mononuclear cells surrounding 

 the lymphoid follicles. We have been fortunate in obtaining material from three 

 mast-cell lesions in cats, the first of which almost exactly duplicates the original 

 case described by the French workers. 



A nine-year-old female castrated cat had to be destroyed on account of a 

 tumour which had been present on its lower eyelid for about three months. 

 Post-mortem examination was carried out five hours after death. A weighed 

 portion of the tumour was sent to us in trichloracetic acid and another portion 

 placed in chloroform water for heparin assay. At autopsy it was also observed 

 that there was enlargement of some of the retropharyngeal and submaxillary 

 lymph nodes and of the spleen. Biopsy specimens for histological examination 

 were taken from these various organs and from the liver, although, unfortunately, 

 no material other than the primary tumour was reserved for histamine or heparin 

 assay. Histologically the tumour was found to consist almost entirely of 



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