Edis, Anthony J.

Experiments were conducted in 35 anesthetized dogs to study the circulatory adjustments, after hemorrhage, mediated by vagal afferents from the cardiopulmonary area. With the aortic baroreceptors and chemoreceptors denervated and carotid baroreceptor and chemoreceptor activity held constant, hemorrhage of 10% of blood volume caused an increase in heart rate and constriction of the resistance vessels of the hindlimb, renal, and mesenteric beds and of the splanchnic venous bed. Vagotomy abolished these responses to hemorrhage, resulting in a greater decrease in blood pressure. With the carotid baroreflex operative, the constriction of the renal and mesenteric resistance vessels and of the splanchnic venous bed were similar to that obtained with only the vagi operative, but the constriction of the hindlimb resistance vessels was much greater and aortic pressure was better maintained. It is concluded that receptors in the cardiopulmonary area, subserved by vagal afferents, exert their main influence on the splanchnic resistance and capacitance vessels and on the renal circulation, whereas the carotid baroreceptors predominantly affect the muscle vessels.

The reflex cardiovascular response to stretch of left pulmonary vein-atrial junctions was studied in anesthetized dogs in which both aortic nerves were cut and the carotid sinuses were isolated vascularly. After thoracotomy, the root of the left lung was tied and a small Silastic balloon (1.5-cm long), attached to a nylon catheter, was inserted into each of the three left pulmonary veins and tied so that its tip lay at the junction of the vein with the left atrium. In six dogs, heart rate response to balloon distension of 2.0 ml was studied over a range of initial heart rates (75 to 240 beats/min) achieved by varying the carotid sinus pressure. On distension of the balloons, slowing occurred if the initial heart rate was > 140 to 150 beats/min and acceleration if it were less. In eight dogs, aortic blood pressure and cardiac output measured before, during, and after balloon distension (0.25 to 2.0 ml) demonstrated a hyperbolic relationship between balloon volume and decrease in calculated systemic vascular resistance. All responses were abolished by vagotomy. The reflex vasodilatation was sustained and caused by decreased adrenergic activity; the reflex bradycardia or tachycardia was due to interplay of vagal and sympathetic cardiac efferents.

Abstract A group of 500 patients with a presumptive diagnosis of primary hyperparathyroidism (HPT) was operated upon at the Mayo Clinic between September 1974 and May 1980 using a standardized operative strategy. Clinical profiles, biochemical data, operative findings and pathological changes are reviewed. Of the 500 patients, 461 (92·2 per cent) were cured after primary cervical exploration. One patient died during the postoperative period, 1 had a permanent unilateral vocal cord paralysis and 10 (2 per cent) had protracted hypoparathyroidism. Owing to the continuing controversy regarding the appropriate therapeutic management of asymptomatic, uncomplicated and mild (‘biochemical’) primary HPT, we further evaluated this surgical experience by comparing the results of operation in two groups of patients: those with (‘biochemical’) HPT (serum calcium < 11 mg/dl) and those with ‘non-biochemical’ HPT (symptomatic or complicated disease or serum calcium > 11 mg/dl). The cure rate in each patient group was greater than 90 per cent. A statistically significant increase in the incidence of negative cervical exploration (4 normal parathyroid glands identified and biopsied) was noted in the ‘biochemical’ group. However, parathyroid disease was found at operation in 92 per cent of these patients. We conclude that cervical exploration in all patients with primary HPT, including those with ‘biochemical’ disease only, is safe and that such an aggressive management policy is justified.

AbstractAt the Mayo Clinic, 103 patients with primary malignant lymphoma of the thyroid have been diagnosed and treated through 1978. This study examines the clinical findings in the 57 new cases seen since the last review in 1966; pathology and survival are evaluated for the series as a whole, including the 46 patients reported previously. Age and sex patterns were unchanged since the earlier review; thyroid lymphoma tended to occur in middle‐ to older‐aged women, and patients typically presented with a fairly rapidly enlarging, painless, and firm thyroid mass. The most common histologic subtype of lymphoma encountered was diffuse large cell (diffuse histiocytic). Hashimoto's disease was found in 36% of the pathologic specimens available for review. Follow‐up was completed for all patients up to 1979. Age, sex, and histologic subtype of tumor did not appear to be significant determinants of prognosis. Patients in whom the lymphoma was confined to the thyroid (intrathyroidal type) had a better overall 5‐year survival rate (86%) than those in whom tumor invaded soft tissues surrounding the hyroid or involved regional cervical nodes (38% for the extrathyroidal type). Almost all of the patients who had intrathyroidal tumors underwent surgical resection before irradiation. However, 3 of the 5 patients in this group who were treated by radiotherapy alone survived more than 5 years. There were approximately equal numbers of patients with the extrathyroidal type of lymphoma who were treated either by radiotherapy combined with surgical resection or by radiotherapy alone. The one form of therapy was just as effective as the other.

AbstractReoperation for persistent or recurrent hyperparathyroidism is more hazardous than is primary cervical exploration and is also much less likely to result in cure of the disease. Only 21 of 34 reoperations (62%) were successful during the period 1970 through 1972 at the Mayo Clinic, compared with success in 312 of 327 primary operations (95%). In 9 patients who had their initial exploration at this institution, the most common cause of failure at the first operation was inadequate treatment of multiglandular disease; in 25 patients who were first operated on elsewhere, missed adenomas were far more common.Parathyroid arteriography and selective venous sampling with parathyroid hormone assays should improve the results of reoperation by providing preoperative localization of hyperfunctioning parathyroid glands in difficult cases. These procedures, however, are expensive and technically difficult, and they are not always successful. They are also associated with a definite morbidity, which must be weighed against any anticipated benefits. The systematic evaluation and treatment of patients facing reoperation for hyperparathyroidism should be undertaken in special centers accustomed to dealing with these difficult problems.