Acute effect of thyroid hormone on insulin secretion in rats

To elucidate the mechanism of thyroid hormone-induced hyperinsulinemia, the acute and direct effect of thyroid hormone administration on insulin secretion was investigated in rats in vivo and in vitro. In the perfused rat pancreas, the addition of thyroxine (10 micrograms/dL) or 3,5,3'-triiodothyronine (150 ng/dL) to the perfusing medium did not affect insulin secretion. The administration of thyroxine (40 micrograms/kg, s.c.) in vivo increased the plasma insulin level from 11 +/- 2 microUnits/mL (mean +/- SD) to 30 +/- 7 microUnits/mL, while blood glucose and plasma glucagon were unchanged. This phenomenon was inhibited completely by the preadministration of oxprenolol hydrochloride (2 mg/kg, s.c.), and inhibited partly by the preadministration of metoprolol tartrate (35 mg/kg, s.c.). These results suggest that thyroid hormone induces hyperinsulinemia via beta-adrenergic stimulation in the rat.     

The role of the superior cervical ganglia in the nocturnal rise of pineal type-II thyroxine 5'-deiodinase activity

Superior cervical ganglionectomy (SCGx) abolished the nocturnal rise in pineal type-II thyroxine 5'-deiodinase (5'-D) activity in both euthyroid and hypothyroid rats. Isoproterenol induced at least as great a rise in diurnal pineal 5'-D in SCGx as in intact rats. These data suggest that beta-adrenergic stimulation through the superior cervical ganglia is essential for the nocturnal rise in pineal 5'-D activity.     

Two cases of persistent hypouricemia associated with diabetes mellitus.

Two patients with diabetes mellitus had persistent hypouricemia due to increased urate clearance; the degree of the apparent renal hypouricemia with uricosuria was quite mild. At the onset of diabetes, their serum urate levels were normal. Even after good diabetes control in both cases, hypouricemia continued. Based on the pharmacological evaluation in both patients, pyrazinamide administration could partially decrease urate clearance, however, suppression by pyrazinamide was less than in normal subjects, and probenecid increased urate clearance. These results suggest that the present cases had a renal abnormality affecting tubular presecretory reabsorption of urate, which might be due to diabetes mellitus.     

Alterations of nuclear pores in preneoplastic and neoplastic rat liver lesions induced by 2-acetylaminofluorene

The nuclear pore density and area were measured on freeze-fracturednuclei of ACI/N rat liver altered foci, adenomas and carcinomasinduced by 2-acetylaminofluorene, and compared with those ofnormal hepatocytes. The pore density of nuclei from these preneoplasticand neoplastic lesions was significantly higher than that ofhepatocytes, but there was no difference between lesions. Thearea of nuclear pores of the focus cells did not differ fromnormal hepatocytes, whereas the areas of pores of adenoma andcarcinoma cells were increased. Moreover, the nuclear pore areaof carcinomas was significantly greater than that of adenomas.These results suggest that some changes may occur in nuclearpores in the progress of tumorigenesis.     

Detection of fecal blood by colloidal gold agglutination using an anti-human hemoglobin monoclonal antibody.

Monoclonal antibodies to human hemoglobin were produced and a colloidal gold agglutination method has been developed for detection of fecal occult blood. Since hemoglobin is composed of the tetramer, alpha 2 beta 2, a single monoclonal antibody-labeled colloidal gold can agglutinate with hemoglobin. The lowest detectable hemoglobin concentration was 0.5 micrograms/ml. A total of 785 fecal samples were determined using colloidal gold agglutination and compared with latex agglutination. The colloidal gold agglutination detected blood in 75 samples, whereas latex agglutination detected blood in 76 samples, and among them 70 were positive in both methods. Overall agreement between the two methods was 98%.     

Single photon emission computerized tomography in childhood hydrocephalus

Single photon emission computerized tomography (SPECT) is now widely used as one of the tools in evaluating cerebral blood flow (CBF). The authors report the CBF changes in childhood hydrocephalus. Five pediatric cases studied by ¹²³I-IM SPECT in children are presented. The authors counted radioactivities both in early and delayed images in each patient, and calculated the reabsorption ratio (RR). Two negative-RR cases and three positive-RR cases were found. All of the negative-RR patients had a poor prognosis, while all of the positive-RR patients had a favorable outcome.     

Uptake of 99Tcm-MDP in lung metastasis from osteosarcoma: clinical and animal studies

Bone scintigraphy was performed in 17 patients with previously known lung metastases of osteosarcoma. 99Tcm-MDP uptake was observed in all primary bone lesions but lung metastatic lesions were positive in only six patients (35%). 99Tcm-MDP uptake by lung metastases was significantly correlated with bone and osteoid formation in the metastatic lesions and preoperative serum ALPase values. These clinical observations were confirmed by using nude mice transplanted with human lung metastatic osteosarcoma. 99Tcm-MDP scintigraphy appears to be useful for detecting lung metastases of osteosarcoma only in a selected group of patients.     

Lipid metabolism in experimental acute pancreatitis

In order to study the changes of lipid metabolism in acute pancreatitis, the following experiments were performed in monogrel dogs. Bile-induced pancreatitis (severe type) and collagenase-induced pancreatitis (mild type) were prepared, and changes of FFA, TG, IRI and IRG were determined for one week. In addition, IVFTT and PHLA were determined at 24th hour, on the 3rd day and 7th day. A rise of FFA was observed during the first 24 hours, which was considered the lypolytic stage. On the 3rd day TG reached the maximal level, while K values in IVFTT and PHLA showed the lowest levels. The above results suggest that the elimination mechanism of TG was impaired on the 3rd day. Changes of FFA, TG, IRI and IRG showed marked differences between the two groups. Therefore it is thought that lipid metabolism in acute pancreatitis is regulated by balance of endogenous pancreatic hormones.