Experience with malignant tumors of the thyroid gland in a private surgical practice.

A review of malignant tumors of the thyroid encountered in a noninstitutional, private surgical practice has been presented. Clinical judgment, coupled with radioactive iodine scanning, has given effective diagnostic direction. Subtotal thyroidectomy, as used by our group, has achieved satisfactory results in this relatively small number of malignant tumors of the thyroid gland. Hopefully, this experience has held up satisfactorily under scrutiny and will be meaningful to other surgeons in similar settings.

Elective hepatic resection.

Significant salvage of patients with a wide variety of cysts and benign tumors of the liver and of some patients with biliary strictures can be achieved by hepatic resection in carefully selected clinical situations with a low operative mortality rate and an acceptable postoperative complication rate. Still to be determined is the role of hepatic resection in metastatic carcinoma and sarcoma of the liver, where survival is modest but measurable, but important palliation can be achieved. Hepatomas should be resected when possible, but hepatic resection for aid in resection of bile duct carcinoma has proved generally unrewarding.

Catabolism of secretin by the liver and kidney.

We have investigated the roles of the liver and the kidney in the catabolism of secretin, using a specific and sensitive radioimmunoassay. Dogs were prepared with sampling catheters in the aorta, hepatic vein, portal vein, and renal vein and with electromagnetic flow probes on the portal vein, hepatic artery, and renal artery. Secretin levels in the vessels entering and leaving the liver and kidney were determined by radioimmunoassay and the total mass of secretin [concentration (picograms per milliliter) X plasma flow rate (milliliter per minute)] was calculated during an intravenous infusion of exogenous secretin and during release of endogenous secretin by acidification of the proximal intestine. The total masses of secretin entering and leaving the liver were the same during secretin infusion and during the release of endogenous secretin. Under conditions of elevation of plasma secretin, however, the kidney extracted 30 percent of arterial secretin during secretin infusion and 45 percent during release of endogenous secretin. Clearly the kidney is a major site of secretin catabolism.

Disappearance half-time of endogenous and exogenous secretin in dogs.

We have used a sensitive and specific radioimmunoassay to measurespectively. the disappearance half-times of exogenous porcine secretin and endogenous canine secretin in the dog and found them to be 2-45 and 2-85 minutes, respectively.

Suppression of gastrin release and gastric secretion by gastric inhibitory polypeptide (GIP) and vasoactive intestinal polypeptide (VIP).

Five dogs prepared with Heidenhain pouches received infusions of saline, GIP and VIP before and after a standard meat meal. Blood samples were obtained under basal conditions and at subsequent intervals for measurement of gastrin, insulin, GIP and VIP by radioimmunoassay. GIP and VIP infusions had no effect on basal levels of gastrin. GIP and VIP (in common with secretin and glucagon) were found to suppress food-stimulated release of gastrin and gastrin-stimulated acid secretion from the Heidenhain pouch. Insulin levels were significantly elevated during GIP and VIP infusions. Food released GIP (and perhaps VIP.

The effects on gastrin and gastric secretion of five current operations for duodenal ulcer.

We have measured serum gastrin and gastric acid secretion in 66 duodenal ulcer patients before and after vagotomy and pyloroplasty (V + P--15 patients), selective proximal vagotomy without drainage (SPV - D--11 patients), and with drainage (SPV + D--19 patients), and vagotomy, antrectomy, and either gastroduodenostomy (V + BI--15 patients) or gastrojejunostomy (V + BII--6 patients). Basal and peak postprandial gastrin levels were increased in postoperative V + P, SPV - D, and SPV + D patients. Basal and peak postprandial levels of gastrin were unchanged after V + BII, indicative of duodenal release of gastrin. Gastrin response to food was abolished in V + BII patients. Acid output was reliably reduced after all five operations; reduction was greatest in patients after antrectomy and least in patients after SPV. No beneficial results were found with drainage in SPV patients. Acid secretion increased with time in SPV patients, especially those with drainage.

Direct influence of blood viscosity on pulmonary vascular resistance.

When cardiac output is maintained constant in the intact animal, changes in blood viscosity exert a direct and rapid effect on pulmonary vascular resistance. The presence of intact cardiopulmonary reflex mechanisms does not alter the direct influence of blood viscosity on pulmonary vascular resistance.

Cholecystokinin metabolism in man and dogs.

We have developed a sensitive, specific and reproducible radioimmunoassay for cholecystokinin (CCK) with which basal levels of CCK of between 400-800 pg/ml have been measured in normal man, in patients with diabetes and with duodenal ulcer disease, and in normal dogs. After a meal, circulating levels of CCK rose to 1000-1200 pg/ml in human subjects. Release of CCK was more rapid in diabetic and duodenal ulcer patients than in normal subjects, but elevated postprandial levels persisted much longer in normal subjects. Patients with the Zollinger-Ellison syndrome had elevated values of cholecystokinin which rose after a meal. Lack of correlation between elevated basal levels of gastrin and CCK in patients with the Zollinger-Ellison syndrome suggest that the hypercholecystokininemia may be absolute. The disappearance half-time of exogenous CCK was about 21/2 minutes in normal subjects as well as in diabetic and duodenal ulcer patients. Studies in dogs demonstrated no uptake of basal levels of cholecystokinin by the kidney; on infusion of exogenous CCK-33, the kidney extracted 43% of the total CCK presented and 56% of the integrated CCK. We conclude that: 1) circulating basal and postprandial levels of CCK may be measured in a reproducible fashion; 2) postprandial release of CCK is more rapid in diabetic and duodenal ulcer patients than in normal man; 3) the disappearance half-time of exogenous CCK in man and dogs is about 21/2 minutes; 4) the kidney is a major site for uptake of CCK.

Natural history and experience with diagnosis and treatment of the Zollinger-Ellison syndrome.

With better methods of diagnosis, patients will be identified earlier in the course of their disease and will often have atypical and borderline manifestations of the syndrome. Serum gastrin measurements with calcium and especially with secretin challenge will be the most important method of diagnosis. Any patient with acid hypersecretion who has a high serum gastrin level that does higher on secretin infusion should be considered to have the Zollinger-Ellison syndrome. A firm diagnosis of the Zollinger-Ellison syndrome should be made, if at all possible, prior to operation. At operation, a thorough search of the pancreas, duodenum, stomach, greater and lesser omentum and liver should be made for primary and secondary gastrinomas. If the preoperative data firmly establish the diagnosis of the Zollinger-Ellison syndrome, a total gastrectomy should be carried out even if no primary tumor is found. Similarly, a total gastrectomy should be done even if there are massive hepatic metastases. If total gastrectomy is not performed, the patient is apt to die of complications of acid hypersecretion. The only possible exceptions to the rule of always performing a total gastrectomy are in asymptomatic patients with easily excisable tumors or patients with tumors of the duodenum that are easily excisable, providing that in both instances after the excision of the tumor the output of gastric acid as measured at operation is immediately halted. All possible metastatic tumor tissue should be removed. The more tumor tissue removed, the longer the patient will survive. Metastases should be treated aggressively. They do not disappear after total gastrectomy in our experience, and they may kill patients. Patients should be followed after operation with serial measurements of serum gastrin concentrations and by hepatic scintillation scans and hepatic angiography. If hepatic metastases develop, intrahepatic artery infusions of 5-fluorouracil may slow tumor growth.