Sequential CT observations of irradiated intracranial germinomas

Computed tomography (CT) has improved the accuracy of preoperative diagnosis of intracranial tumors. CT findings of germinoma are a mass of isodensity or of slightly increased density with significant, homogeneous enhancement after intravenous contrast injection. These findings are characteristic but not pathognomonic, and differential diagnosis from other solid tumors is not easy. Cerebrospinal fluid cytology and response to irradiation aid in this differential diagnosis. The nine cases of germinoma reported showed rapid response to irradiation even at small doses (600 rad), and complete disappearance of the mass on CT at 1,600--3,300 rad. Other radiosensitive masses to be differentiated in the pineal region are pinealocytoma or pinealoblastoma.

Peptidyl puromycin synthesis; effect of several antibiotics which act on 50 S ribosomal subunits

The effects of several antibiotics which are know to bind with 50 S ribosomal subunits, on the formation of several di- and tri-peptidyl puromycins have been examined. Tylosin and spiramycin inhibited the formation of phenylalanyl-(14)C-phenylalanyl-puromycin, glycyl-(14)C-phenyllalanyl-puromycin, leucyl-(14)C-phenylalanyl-puromycin, N(epsilon)-carbobenzoxylysyl-(14)C-phenylalanyl-puromycin, and valyl-glycyl-(14)C-phenylalanyl-puromycin as well as N-acetyl-(14)C-phenylalanyl-puromycin. Of these compounds, erythromycin and oleandomycin selectively inhibited the formation of phenylalanyl-(14)C-phenylalanyl-puromycin. Although chloramphenicol and lincomycin inhibited the formation of most of these peptidyl puromycins, the formation of phenylalanyl-(14)C-phenylalanyl-puromycin and leucyl-(14)C-phenylalanyl-puromycin was found to be resistant to these antibiotics. So far, no significant effect of siomycin has been observed on pepetidyl puromycin formation in the absence of G factor.