Subthalamic nucleus stimulation in Parkinson's disease : anatomical and electrophysiological localization of active contacts.

OBJECTIVES: 1 - To assess the anatomical localization of the active contacts of deep brain stimulation targeted to the subthalamic nucleus (STN) in Parkinson's disease patients. 2 - To analyze the stereotactic spatial distribution of the active contacts in relation to the dorsal and the ventral electrophysiologically-defined borders of the STN and the stereotactic theoretical target. METHODS: Twenty-eight patients underwent bilateral high-frequency stimulation of the STN (HFS-STN). An indirect anatomical method based on ventriculography coupled to electrophysiological techniques were used to localize the STN. Clinical improvement was evaluated by Unified Parkinson's Disease Rating Scale motor score (UPDRS III). The normalized stereotactic coordinates of the active contact centres, dorsal and ventral electrophysiologically-defined borders of the STN were obtained from intraoperative X-rays images. These coordinates were represented in a three-dimensional stereotactic space and in the digitalized atlas of the human basal ganglia. RESULTS: HFS-STN resulted in significant improvement of motor function (62.8%) in off-medication state and levodopa-equivalent dose reduction of 68.7% (p < 0.05). Most of the active contacts (78.6%) were situated close to (+/- 1.6 mm) the dorsal border of the STN (STN-DB), while 16% were dorsal and 5.4% were ventral to it. Similar distribution was observed in the atlas. The euclidean distance between the STN-DB distribution center and the active contacts distribution center was 0.31 mm, while the distance between the active contacts distribution center and the stereotactic theoretical target was 2.15 mm. Most of the space defined by the active contacts distribution (53%) was inside that defined by the STN-DB distribution. CONCLUSION: In our series, most of the active electrodes were situated near the STN-DB. This suggests that HFS-STN could influence not only STN but also the dorsal adjacent structures (zona incerta and/or Fields of Forel).

Death and replacement of uterine epithelial cells during oil-induced deciduoma development in the mouse.

BACKGROUND: A decidual cell reaction can be induced in rodent endometrium by an intrauterine injection of oil. The epithelial lining is thought to be instrumental to transduce intralumenal stimuli for decidualization. One of the consequences of oil injection is the death of uterine epithelial cells. No information is available on the effect that sustained contact with oil has on the epithelium. METHODS: A decidual cell reaction was induced in 4-day pseudopregnant mice by injection of 30 microliters of arachis oil into the uterine lumen. Samples from the uteri were collected 24, 48, and 72 h after the injection and prepared for transmission electron microscopy. RESULTS: Twenty-four hours after the oil injection, some of the initial modifications of epithelial cell surfaces were very similar to those induced by the contact with the blastocyst during normal pregnancy. Uterine epithelial cells internalized injected oil and many cells were seen in various stages of degeneration. At 48 h, many epithelial cells were detached from the basal lamina. At 72 h, the uterine lining was re-established by flattened cells. CONCLUSIONS: The contact of oil with the uterine epithelium of pseudo pregnant mice induces epithelial cell death in the antimesometrial region of the uterine crypt. There is, however, replacement of epithelial lining by epithelial cells, which probably migrate from the mesometrial region of the crypt. The prolonged presence of oil within the uterine lumen seems to induce cycles of epithelial cell death and replacement.