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The reflex haro-and chenioreceptor control of the cardiovascular system has for many years moused considerable interest, especially since it has recently been shown that the activity of the carotid baroreceptors is not only dependent on the distension of the sinus region by the blood pressure. The activity of a t least one type of the receptors is also markedly affected by local changes in intramural tension, caused by the smooth inuscle cells. Thus, local applications of vasocoiistrictor drugs induce a considerable discharge of this baroreceptor type, and there is some experimental evidence, indicating that stimulation of sympathetic constrictor fibres to the carotid sinus wall can result in a similar receptor activation (for lit. see HESMAXS and NEIL 1958, pp 72--82).-Practically all our knowledge is derived from experiments on animals, however, and in man the carotid sinus mechanism has heen investigated mainly h v way of studies, where the baroreceptors have been activated by applying external pressure to the carotid sinus region.The carotid siniis region is, however, routinely explored in surgical treatment of cancer in the neck. The unavoidable traction and manipulation of vessels and nerve trunks during such operations often provoke dramatic reflex cardiovascular effects, which 138

Plasma insulin response to glucose infusion was found to be markedly increased in 20 patients with active acromegaly and with normal intravenous glucose tolerance. The insulin response was more pronounced in patients with highly active acromegaly than in those showing moderately active disease. In five patients with active acromegaly and with decreased glucose tolerance the insulin response was delayed and smaller than normal, i. e. similar to that seen in diabetic subjects without acromegaly. After successful treatment of the acromegaly insulin response to glucose infusion was normalized in the patients with normal glucose tolerance. In those with decreased glucose tolerance the diabetic type of insulin response remained unchanged even when the glucose tolerance was normalized. It is suggested that diabetes in connection with acromegaly develops only in prediabetic individuals, i.e. subjects with decreased insulin response to hyperglycaemia, who are unable to overcome the diabetogenic effect of growth hormone by compensatory hyperinsulinism.

The prerequisite for an adequate treatment of a parotid tumor is a correct diagnosis — a diagnosis based on well delimited histological types of tumor. A classification with a clear delimitation between benign and malignant types of tumor is presented. The prognosis, relation to the facial nerve and the radiosensitivity of the different types of tumor in this classification have been studied in a series of about 2,000 parotid tumors. The extent of the surgical intervention — subtotal or total parotidectomy, radical neck dissection, sacrificing of the facial nerve — and the decision to perform preoperative irradiation are determined by the type of tumor; therefore, a correct diagnosis of the tumor before treatment is important as the primary diagnostic method aspiration biopsy has been routinely employed during the last decade.