[Effect of puberty on the development of diabetic microangiopathy]. / Pubertás hatása a diabeteses microangiopathia alakulására.

Fluorescein angiography was used to follow the development of retinal microangiopathy at the time of puberty in 34 children with type I diabetes. When the results were compared with those for the control children who had suffered from the disease for a similar length of time, it was concluded that (in contrast with certain literature data) the process of sexual maturation does not essentially influence the development of retinal microangiopathy if the diabetes is maintained under good control for a long-lasting period. Appreciable roles in the rapid progression that is frequently observed in early adulthood are attributed to the sudden changes in the previously systematic living conditions (school, family, etc.).

Recessive genetic deregulation abrogates c-myc suppression by interferon and is implicated in oncogenesis.

In a previous study we demonstrated that many hematopoietic tumor cells are resistant to the inhibitory effects that interferon exerts on c-myc mRNA expression without losing other receptor-mediated intracellular responses (M. Einat, D. Resnitzky, and A. Kimchi, Nature [London] 313:597-600). We report here that this partial resistance was overridden in two independent stable somatic cell hybrids prepared by fusion between sensitive and resistant cells. The c-myc mRNA transcribed from the active allele of the resistant parent cell was reduced by interferon within the context of the cell hybrid. It was therefore concluded that changes in the cis-acting sequences of c-myc were not involved in this type of relaxed regulation and that resistance resulted rather from inactivation or loss of postreceptor elements which operate in trans. The growth-stimulating effect that this genetic deregulation might have on cells was tested in experimental systems of cell differentiation in which an autocrine interferon is produced. For that purpose we isolated variant clones of M1 myeloid cells which were partially resistant to alpha and beta interferons and tested their growth behavior during in vitro-induced differentiation. The resistant clones displayed higher proliferative activity on days 2 and 3 of differentiation than did the sensitive clones, which stopped proliferating. The loss of c-myc responses to the self-produced interferon disrupted the normal cessation of growth during differentiation and therefore might lead cells along the pathway of neoplasia.

[On the appearance of the eye fundus in polycythaemia vera (author's transl)]. / Uber das Augenhintergrundbild bei Polycythaemia vera

The authors discuss the ophthalmological and physical symptoms of polycythaemia vera. They established that the severity of the changes in the fundus depend in the same way on the red cell count and the duration of the illness. In an attempt to find the cause of the complications communicated in the literature in arterial spasm and venous stasis, the authors compared statistically the less severe cases and those cases with arterial stenosis which can also be found in uncomplicated cases, and the cases with venous stasis. In the group with arterial stenosis they showed that its occurrence was not associated with the hypertension often found in polycythaemia vera.