Histologic evaluation of tumor persistence at the surgical margins in oral cancer: an evaluation of all surgical margins using paraffin-embedded sections and its usefulness and limitations.

An evaluation of frozen sections at all surgical margins (Mohs' surgery) was attempted in three patients, in order to determine whether or not a tumor persisted at the surgical margins following surgery for carcinoma of the oral cavity. However, sectioning from the fresh tissue was difficult, and moreover, duration of the surgery was lengthened. It thus seems that this method is not suitable for a routine evaluation of the surgical margins. Based on this, surgical specimens after formalin fixation were evaluated in eight patients. The use of paraffin-embedded sections compensates the disadvantages in using frozen sections. On the other hand, when a residual tumor is detected, any additional excision should be delayed. In two patients, who were evaluated using paraffin-embedded sections, a persistent tumor was detected. In another patient a recurrent tumor developed, despite having completely tumor-free margins. In this patient, the growth of the tumor appeared to be discontinuous. When skip lesions are histologically suggested, adjuvant therapy including radiotherapy should be considered, even when a persistent tumor is not evident. A reliable evaluation of all surgical margins is difficult in either a T4 tumor or in a malignant tumor of the gingiva and hard palate. Microscopic evaluation of all surgical margins using paraffin-embedded sections is considered to be practical in helping to elucidate the microscopic extent of a tumor, although there are several limitations in its application.

Down modulation of N-myc, heat-shock protein 70, and nucleolin during the differentiation of human neuroblastoma cells.

Cultured human neuroblastoma (GOTO) cells were induced to differentiate by dibutyryl cyclic AMP (Bt2cAMP) and/or retinoic acid (RA). A combination of Bt2cAMP (1 mM) and RA (1 microM) yielded the most significant networks of neurites after 3 to 4 days, this being associated with the reduction of N-myc mRNA levels. Next, we examined several cellular genes that were possibly linked with changes in N-myc gene expression under these conditions. Among the genes examined, both nucleolin and a major heat-shock protein (hsp70) mRNAs showed changes concomitant with those in N-myc mRNA levels when induced by Bt2cAMP and RA. Dibutyryl cAMP alone induced several short cellular processes and caused a marked decrease in N-myc mRNA within 2 days. RA alone induced a few long and straight neurites along the longitudinal axis of individual cells and a significant decrease in growth rate but showed neither network formation nor a decrease in N-myc gene expression. These results indicate differential effects of Bt2cAMP and RA on the regulatory mechanisms of both cell proliferation and differentiation and also indicate a possible association of expression of N-myc gene with those of hsp70 and nucleolin genes.

The accuracy and usefulness of frozen-section diagnosis.

A retrospective review of 57 patients, who had received frozen-section diagnoses, was performed both to ascertain the accuracy of diagnosis and to evaluate its usefulness in assessing tumor surgery. Except for 2 cases, each with a parotid gland tumor, the frozen-section diagnoses were consistent with the final diagnoses using permanent paraffin sections. Fifteen cases with either T1 or T2 squamous cell carcinoma of the oral cavity and 2 cases with malignant salivary gland tumor, showing tumor-free surgical margins by frozen-section examination, were followed. A local recurrence of the carcinoma was observed in 1 case during the follow-up period. Prior to neck dissection, lymph node metastases were examined using frozen sections. Ten cases, which were diagnosed as negative for metastasis, showed no subsequent development of cervical node metastasis.

The change in the electrical resistance of the scala media produced by vasopressin.

The electrical resistance of the scala media (Rm) in the basal turn of the guinea pig was measured during perilymphatic perfusion with vasopressin. As the endocochlear potential (EP) diminished under the influence of vasopressin (0.1 mM), so the Rm increased. The Rm decreased when the EP decreased by vasopressin recovered above the pre-asphyctic level after the termination of temporary asphyxia. The present study demonstrates that the EP decrease produced by vasopressin is associated with the increase in Rm.

Effects of alcohol diet from the fetal period on lipid metabolism in rats.

The effects of maternal alcohol consumption on lipid metabolism in the litter liver were examined in the rat. Rats reared from their fetal period to adulthood with liquid alcohol diet (fetal alcohol group) did not show any lipid accumulation in the livers. Liver perfusion experiments showed an increased oxygen consumption in the liver to a load of physiological concentration of palmitate. On the contrary, the response of oxygen consumption in fetal control rat livers (reared with non-alcohol liquid diet) to palmitate was found to be depressed. 14CO2 production rate from 14C-palmitate in perfused livers showed a significant increase in fetal alcohol group as compared with controls. No difference in 14C-palmitate incorporation into tissue lipid was found between fetal alcohol and fetal control groups. These data indicate that when rats are treated with alcohol from fetal period they acquire an ability to elevate FFA oxidation in the liver through metabolic adaptation.