Origin of the frontal somatosensory evoked potential (SEP) by median nerve stimulation was investigated in normal volunteers and in patients with localized cerebrovascular diseases, and the following results were obtained. (1) In normal subjects, SEPs recorded at F3 (or F4) contralateral to the stimulating median nerve were composed of P12, N15, P18.5 and N26. Similar components were recognized in SEP recorded at Fz. (2) In patients in whom putaminal or thalamic hemorrhages had destroyed the posterior limbs of the internal capsules, frontal N15 and parietal N18 (N20) disappeared. These components were also absent in patients with cortical (parietal) infarctions. Among these patients, the thalamus was not affected in cases with putaminal hemorrhages and cortical infarctions. These facts indicate that the generator of the frontal N15 does not exist in the thalamus but that it originates from the neural structure central to the internal capsule, which suggests a similarity to the generator of the parietal N18. Because N15 was recorded in the midline of the frontal region with shorter latency than parietal N18, the frontal N15 might represent a response to the sensory input of the frontal lobe via the non-specific sensory system.

Brain Mapping↗

PubMedDate not supplied

Probability of lymph node metastasis in small gastric cancer tumor: is it an indication for limited surgery?

The purpose of this study was to determine the factors that are predictive of lymph node metastasis in a small gastric cancer tumor <2 cm in diameter. The clinicopathological features of 17 patients with node-positive small gastric cancer were reviewed from the database of gastric cancer at the Department of Surgery, Sendai National Hospital, Sendai, Japan, and they were compared with those of 131 patients with node-negative cancer. The independent risk factors influencing the lymph node metastasis were determined by multiple logistic regression analysis. Depth of invasion, macroscopic appearance, cancer-stromal relationship, and lymphatic microinvasion were found to be associated with lymph node metastasis. The variables found to be significant risk factors for lymph node metastasis were depth of invasion (P = 0.0250) and lymphatic microinvasion (P = 0.0028). It is possible for even a small gastric cancer tumor to have lymph node metastasis. A surgeon treating a small gastric cancer tumor must consider that although the cure rate is high, >10% of these tumors have lymph node metastases. Because of the possibility of lymph node metastasis, even with accurate knowledge of the depth of cancer invasion, selective performance of local resection or limited surgery with incomplete lymph node dissection is not justified. Accurate preoperative diagnosis and the appropriate decision for surgical indication are important. Large-scale randomized, controlled trials should be performed to show the advantage of limited surgery for gastric cancer.

Adenocarcinoma↗

PubMedDate not supplied

The role of biological markers in epidemiological research: future directions.

Explore the source record for details and available documents.

Biomarkers↗