Cellular Variant Research Articles

A novel type of cellular variant with altered expression of virus-induced cell transformation

Abstract Transformed variants were obtained from NRK cells infected by temperature-sensitive avian sarcoma virus mutants and grown at nonpermissive temperature. Most of these variants contained virus still temperature sensitive for transformation, indicating the occurrence of a host-cell modification.

Melanotic tumours (blue naevi) of spinal nerve roots

Four cases interpreted as intraspinal blue naevi are reported. The patients were adults females with an age range between 22 and 60 yr. In three there was a single tumour arising from the cervical posterior nerve roots and in the fourth there were multiple tumours arising from the posterior nerve roots of the spinal cord and occurring within the cerebello--pontine angle. The histological appearances of the tumours were similar in every way to those of dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin-pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. Definite evidence of malignant tranformation was found in two cases and in a third, the appearances were suggestive for early malignant change. Therefore, unlike their dermal equivalents, intraspinal blue naevi appear to have a greater propensity for malignant transformation. In each case a careful clinical examination failed to reveal any evidence of a primary malignant melanoma. In the one case who died and on whom necropsy was performed, the failure to identify a primary cutaneous, mucosal or ocular melanoma substantiated our contention that these tumours were primary.

The ventromedial nucleus of the hypothalamus of sheep (Ovis aries) and the effects on food and water intake following its electrolytic destruction.

A description is presented of the ventromedial nucleus of the hypothalamus (VMN) of sheep following study of paraffin-embedded material stained with a Nissl and a myelin stain. The VMN is related to most structures in the ventrobasal hypothalamus and is ellipsoidally shaped with its poles tilted both medially and anteriorly. Three kinds of neurons can be distinguished under the high power of the light microscope, and other cellular variants are probably the three basic types seen in different orientations. The commonest neuron had bipolar processes and a basophilic line structure apparently curving over the surface of the nucleus. The food and water intake of four sheep with discrete destruction of the VMN is described and compared with sheep with anterior hypothalamic lesions and controls. Discrete destruction of the VMN was without effect on food and water intake. The conclusion is reached that more lateral and ventrolateral areas of the tuberal hypothalamus might be involved in satiety regulation in the sheep.

Beta cell nesidioblastosis in idiopathic hypoglycemia of infancy

A histochemical technique (pinacyanole metachromasia), specific for insulin in vitro and in beta cells of pancreatic tissue sections, was used to study surgically resected pancreases of 12 patients with documented idiopathic hypoglycemia of infancy. Hematoxylin and eosin—stained sections from 3 patients revealed overt hypertrophy and hyperplasia of all insular units. In the pancreases of the other 9 patients, hematoxylin and eosin sections showed histologically unremarkable islets, whereas the histochemically stained sections revealed the presence of many additional beta cells scattered either singly or in small packets of 2 to 6 cells. These were separate from the islets and most often seen about the walls of small ducts or in the glandular acini proper. The term beta cell nesidioblastosis most appropriately describes this cellular variant. These results, including electron microscopic findings of membrane-bound insulin inclusions in many cells, provide histomorphologic correlation with other evidence in support of the concept that excess production of insulin is an important feature of idiopathic hypoglycemia of infancy. A histochemical technique (pinacyanole metachromasia), specific for insulin in vitro and in beta cells of pancreatic tissue sections, was used to study surgically resected pancreases of 12 patients with documented idiopathic hypoglycemia of infancy. Hematoxylin and eosin—stained sections from 3 patients revealed overt hypertrophy and hyperplasia of all insular units. In the pancreases of the other 9 patients, hematoxylin and eosin sections showed histologically unremarkable islets, whereas the histochemically stained sections revealed the presence of many additional beta cells scattered either singly or in small packets of 2 to 6 cells. These were separate from the islets and most often seen about the walls of small ducts or in the glandular acini proper. The term beta cell nesidioblastosis most appropriately describes this cellular variant. These results, including electron microscopic findings of membrane-bound insulin inclusions in many cells, provide histomorphologic correlation with other evidence in support of the concept that excess production of insulin is an important feature of idiopathic hypoglycemia of infancy.

A study of some tumours of human origin—II: Chromosome and late replication analysis of parental tumours, metastasis and ascites of the HR 18 rat tumour

The HR 18 rat tumour derived from a human melanocarcinoma was propagated in solid and permanent ascites form, and heterotransplanted in AKR mice. In the new host the HR 18 tumour preserved its original chromosome constitution and behaved as aggressively as in rat. The karyological uniformity of the HR 18 tumour may account for the invading character of the tumour, as a selected cellular variant, with high malignant potentiality. The comparative chromosome analysis of parental tumour, lung metastasis and ascites form revealed similarities between the solid tumoural forms and differences between these latter and the ascites form. The tumoural growth medium influences the chromosome structure of the neoplastic cells. Late replication pattern of ascites cells was characteristic to rat, some heterochromatic regions were altered, which may be correlated to the malignant transformation of the cells.

Cellular Variants for Blood Groups Within an Established Cell Line

Cellular Variants for Blood Groups Within an Established Cell Line

Some observations on the ultrastructure of a malignant islet cell tumor associated with duodenal ulceration and severe diarrhea

Ultrastructural study of a hepatic metastasis from a malignant islet tumor—associated initially with duodenal ulceration and subsequently with severe diarrhea and hypokalemia—has revealed a dual cell population. The first cellular category comprised cells believed to be alpha cells. The nature of the second group is not clear; they may have represented modified alpha cells. In view of recent evidence incriminating gastrin as the factor responsible for gastric hypersecretion, and in view of the postulated existence of a separate hormone responsible for the severe diarrhea encountered in some patients with islet cell tumors, it is suggested that these two cellular variants may, respectively, have been responsible for the elaboration of factors mediating the physiologic disturbances present in this patient, viz., secretion of gastrin by the alpha cells, and of an intestinal stimulant by cells of the second category, whatever their derivation.