Rikio Furihata

Effect of guanyl nucleotides on the stimulation of adenyl cyclase activity in human thyroid plasma membranes by thyroid-stimulating hormone and prostaglandin E2

Abstract Thyroid homogenates and thyroid plasma membranes were prepared from human thyroid and the effects of thyroid-stimulating hormone (thyrotropin), NaF, and prostaglandins E 1 and E 2 on adenyl cyclase activity in these preparations were studied. The basal level of adenyl cyclase activity in plasma membranes was 5–8 times greater than that of the original homogenates. Adenyl cyclase activity in plasma membranes was stimulated 4.7-fold by 100 munits/ml of thyrotropin and 5-fold by 10 mM of NaF, but the activity in the homogenates was only stimulated 2-fold by either thyrotropin or NaF. Prostaglandin E 1 (10 −6 −10 −3 M) and prostaglandin E 2 (10 −7 −10 −4 M) failed to stimulate adenyl cyclase activity in plasma membranes, but they did stimulate adenyl cyclase activity in the homogenates. A marked stimulatory effect of prostaglandin E 2 (10 −5 M) on adenyl cyclase activity in plasma membranes resumed in the presence of GTP (10 −7 −10 −4 M), although GTP itself only slightly stimulated enzyme activity. GDP and GMP were also effective in this respect, although their potencies varied from compound to compound. GTP potentiated slightly the action of thyrotropin on adenyl cyclase in plasma membranes, but it significantly depressed an increase of enzyme activity produced by NaF. Since GTP did not affect the ATP-regenerating system, it seems that GTP, GDP or GMP was required for the manifestation of prostaglandin E 2 action on adenyl cyclases of human thyroid plasma membranes.

Three cases of early stage carcinoma of the gallbladder

SummaryThree cases of early stage carcinoma of the gallbladder are reported. In two cases, radiolucent shadow was demonstrated on cholecystogram. The masses were papillary adenomas with foci of adenocarcinoma. In the third case, the cholecystogram did not reveal particular findings except for shadows of numerous tiny gallstones. The malignancy was completely unexpected clinically, even after gross inspection of the organ. It was an incidental finding of microscopic examination, which disclosed abundant Rokitanskγ-Aschoffs sinuses associated with foci of cytologically malignant cells in the muscular layer. It was explained as malignant change of epithelium on one of the sinuses.All three patients underwent simple cholecystectomy. So far they have been free from evidence of metastasis or recurrence. The diagnosis and treatment of early carcinoma of the gallbladder are discussed.

Smooth muscle tumors of the stomach

In retrospect, we analyzed 12 cases of gastric smooth muscle tumor, nine cases of leiomyomas and three of leiomyosarcomas. In only half the number of these patients was an adequate preoperative diagnosis made. Ulceration of the tumor apparently led to a misjudgment in some cases. Features more relevant to leiomyosarcoma than to leiomyoma were findings of a larger size, exogastric growth, ulceration and tumor in patients over 50 years of age. It is stressed that enculeation is the treatment of choice for leiomyoma and an extensive gastrectomy for cases of leiomyosarcoma.

Clinicopathological studies on thyroglossal duct remnant

The clinicopathological findings in 48 cases underwent complete surgical excision of epithelial tissue of the thyoglossal duct remnants were reviewed. Simple incision of the cyst does not seem to have any therapeutic value and would be followed frequently by recurrence. The widely used Sistrunk procedure2,6 surgical excision of the central portion of the hyoid bone together with fibrous tract extending to the base of tongue, seems to be not warranted in some cases so long as complete eradication of the epithelial tissue can be made.

Diagnostic and therapeutic considerations of myogenic tumors of the duodenum

SummaryThree cases of duodenal myogenic tumor are described in detail. All the three were surgically treated and the final diagnoses were histologically established. The three consisted of two leiomyomas and one leiomyosarcoma. To make clinical diagnosis, roentgenologic, endoscopie, and angiographie examinations were empolyed. The selective angiography was more reliable than endoscopie biopsy to make a differential diagnosis whether a tumor was benign or malignant. Surgical procedures were required not only for malignant myomatous lesions but also for benign lesions because the latter also produce a high incidence of hemorrhage from ulcèration of the tumor. Out of the three cases, one was successfully treated by enucleation but the other two were undergone more extensive surgery such as a Whipple’s procedure or wide resection of the duodenal wall with side-to-side duodenojejunostomy. Operative techniques are discussed in detail basing on the biological characteristics, location, and size of the tumor.