The excitement of multiple noradrenergic cell groups in the rat brain related to hyperbaric oxygen seizure.

The mechanism of oxygen toxicity for central nervous system and hyperbaric oxygen (HBO) seizure has not been clarified. Noradrenergic cells in the brain may contribute to HBO seizure. In this study, we defined the activation of noradrenergic cells during HBO exposure by c-fos immunohistochemistry. Electroencephalogram electrodes were pre-implanted in all animals under general anesthesia. In HBO seizure animals, HBO was induced with 5 atm of 100% oxygen until manifestation of general tonic convulsion. HBO non-seizure animals were exposed to 25 min of HBO. Control animals were put in the chamber for 120 min without pressurization. All animals were processed for c-fos immunohistochemical staining. All animals in the HBO seizure group showed electrical discharge on EEG. In the immunohistochemistry, c-fos was increased in the A1, A2 and A6 cells of the HBO seizure group, and in the A2 and A6 cells of the HBO non-seizure group, yet was extremely low in all three cell types in the control group. These results suggest the participation of noradrenaline in HBO seizure, which can be explained by the early excitement of A1 cells due to their higher sensitivity to high blood pressure, hyperoxia, or by the post-seizure activation of all noradrenergic cells.

[A case of advanced esophageal cancer that has come back eight years after combined modality therapy].

The case is for a woman of 77 years old. In February 1992, right thoracotomy subtotal thoracic esophagectomy was performed after performing preoperative chemotherapy (FP therapy) for advanced esophageal cancer for two courses. The pathological diagnosis was Mt, mod. diff. sqcc, mp, n4 (#2: 1/13, #9: 3/4), ly2, v0, stage IVa. As a postoperative adjuvant therapy, FP therapy was performed for two courses and we took a wait-and-see approach as an outpatient since then. As we found lymph node metastasis surrounding the root of celiac artery and right renal vein by an abdominal CT in October 1999, nedaplatin+5-FU therapy was performed for 5 courses/24 weeks as second-line chemotherapy, and furthermore, a radiation therapy, linac 50 Gy was performed. The involved lymph node was reduced and the therapy evaluation was CR. After that, a home-healthcare period of about six months was obtained. We have experienced a case of advanced esophageal cancer that has come back eight years after combined modality therapy, and after that, the patient could obtain a long-term survival with a marked effect of chemotherapy.

Measurement of GABA and glutamate in vivo levels with high sensitivity and frequency.

In the present protocol, we demonstrate a high-performance liquid chromatography (HPLC) system that enables detection of very low amounts of gamma-aminobutyric acid (GABA) (0.03 pmol) and glutamate (0.8 pmol). The HPLC system consists of two pumps, an electrochemical detector, a high-pressure six-way switching valve, a guard column, a microbore column, and a column oven. A microdialysis probe was implanted in the right parietal cortex in rats. Dialysates were collected every 5 min and were split into two equal aliquots for separate analysis of GABA and glutamate. After derivatization with o-phthalaldehyde (OPA), samples were isocratically separated and purified by the guard column. To make the peak of GABA or glutamate appear in an opportune place in a chromatogram, a six-way switching valve was used to control the eluate containing GABA or glutamate to be led to the microbore column and electrochemical detector. By the use of this system, decrease in extracellular concentration of GABA, which precedes the appearance of electrical discharge initiated by hyperbaric oxygen (HBO2) exposure, was detected by microdialysis at the time resolution of 5 min.