Tsutomu Miyamoto

Clinical values for an index predicting postoperative residual liver function by pre-operative liver-scintigraphy in patients with liver disease

Hepatic resection is essential in treating hepatocellular carcinoma. However, before an operation, it is difficult to predict the functional reserve in the remnant following massive resection. We devised an original method by which effective liver volume was measured by liver scintigraphy. In order to predict the residual liver function before hepatic resection in a preoperative radiocolloid study, we obtained a predictive index by combining the K values with effective liver volumes which seemed to have the estimated residual liver function. Twenty-one patients with liver or biliary tract disease were selected at random for the present study. We divided them into 3 groups in accordance with prognosis after hepatic resection. There were statistically significant difference between the deceased group who died from hepatic failure and the group who died from causes other than hepatic failure ; and between the deceased group who died from hepatic failure and the living group in the preictive index (p< 0.01). Our data suggest that if the predictive index is above 0.45, the probability of hepatic failure after hepatic resection is low. We concluded that our predictive index is useful to use in preoperative prediction of post-hepatectomic residual liver function.

A kinetic study on secretion and elimination of endogenous thyrotropin in the thyrotropin-releasing hormone test

Serum thyrotropin (TSH) concentrations in normal young men were measured by a highsensitivity immunoradiometric assay before and after intravenous administration of 500μg of TSH-releasing hormone (TRH). A kinetic model was applied to evaluate the secretion rate both before (V0) and after (V0+V* at maximum rate) the administration of TRH, the elimination constant (K), the latent time (L) between TRH administration and start of the stimulated secretion, and the total amount of TSH (T) released in response to TRH. Vo, V* and T varied widely from individual to individual, but correlated well with TSH before TRH administration (r=0.93, 0.80 and 0.87, respectively). A few minutes (1.89± 1.30 min) after the administration of TRH, the secretion of TSH (0.025±0.016μU/min ml) was stimulated, and the total release over about 1 h was 12.5±5.6,μU/ml. Serum TSH was maximum at 31.5±5.7 min. The half-time of disappearance of TSH was 42±9 min. These data confirm that the stimulated secretion continues for more than 30 min, and that the pituitary releases 43.2±22.9 mU of TSH (assuming the distribution volume of TSH is 5.8% of body weight) in response to TRH, an amount which correlates closely (r=0.91) with TSH before TRH administration.