Repetitive transcranial magnetic stimulation for protection against delayed neuronal death induced by transient ischemia

OBJECT: Data in the present study demonstrate that repetitive transcranial magnetic stimulation (rTMS) induces ischemic tolerance against delayed neuronal death (DND) of hippocampal neurons following an otherwise lethal ischemic insult. METHODS: Various regimens of rTMS were delivered to adult gerbils at various times prior to an episode of ischemia induced by transient (5-minute) bilateral common carotid artery (CCA) occlusion. The extent of DND in the CA1 region of the hippocampus was assessed quantitatively 7 days after the transient ischemic episode. When rTMS was delivered 2 to 5 days prior to bilateral CCA occlusion, DND was substantially attenuated; delivery of rTMS 12 to 24 hours prior to occlusion induced partial tolerance. In the group of animals that had received stimulation 2 days prior to occlusion, neuron density in the CA1 sector was significantly higher (three gerbils, 210.33, 86.01% of normal) than in the group that experienced ischemia only (three gerbils, 10.66, 4.36% of normal). A similar degree of neuron sparing occurred when stimulation was delivered 3, 4, or 5 days prior to occlusion. Note that rTMS was effective when it was delivered at frequencies of 25 and 50 Hz. Stimulation at 25 Hz for 128 seconds (3200 pulses) was more effective than stimulation at 50 Hz for 64 seconds (3200 pulses) or 128 seconds (6400 pulses), however. CONCLUSIONS: Noninvasive rTMS represents an important tool for exploring the mechanisms of ischemic tolerance and preventing ischemic neuronal damage.     

小鼠骨组织中转录调控因子CBF1的表达

目的: 探讨转录调控因子CBF1(C-promoter binding factor-1, CBF1)在成鼠骨组织以及小鼠胚胎性骨组织的表达情况.方法: 采用实时RT-PCR方法检测包括骨组织在内的成年小鼠13种器官组织中CBF1的相对表达水平.采用组织原位杂交技术检测小鼠胚胎性趾骨、肋骨和椎骨中CBF1的分布.结果: 转录调控因子CBF1在成年小鼠各组织器官中广泛存在,在骨组织中检测到较高的CBF1表达水平.原位杂交分析显示: 发育中的趾骨和肋骨软骨细胞CBF1阳性染色,染色阳性程度与软骨细胞的分化程度有关;肋骨和椎骨骨化区周围成骨细胞呈强阳性染色;埋入骨基质的骨细胞则呈弱阳性染色.结论: 转录调控因子CBF1参与了小鼠骨组织的发育形成,可能也参与了成熟骨组织的改建和代谢.     

Recovery of parathyroid function after total thyroidectomy: long-term follow-up study

BACKGROUND: To prevent postoperative hypoparathyroidism following total thyroidectomy, the parathyroid glands are preserved in situ and/or resected or devascularized parathyroid glands are autotransplanted. A retrospective investigation was conducted utilizing biochemical and specific endocrine assessments to evaluate the difference in recovery of parathyroid function in the long term. METHODS: A total of 103 patients underwent total thyroidectomy at Second Department of Surgery, School of Medicine, Kagawa University between 1990 and 1998. These patients were divided into a preservation group (n = 17), with only preserved glands in situ; a combination group (n = 72), consisting of patients with one or more parathyroid glands preserved in situ and one or more autotransplanted parathyroid glands; and an autotransplantation group (n = 14), with only transplanted glands. RESULTS: The overall incidence of permanent hypoparathyroidism in the preservation group, the combination group, and the autotransplantation group was 0%, 1.4%, and 21.4%, respectively. The mean levels of intact parathyroid hormone in the preservation group, the combination group, and the autotransplantation group recovered to 102%, 107%, and 50% of the preoperative levels at 5-year follow up. CONCLUSION: The results of the present study suggest that parathyroid glands should be preserved in situ whenever possible, to promote better recovery of postoperative function, and that only autotransplantation produces inadequate recovery of long-term function.     

Growth fractions of breast cancer in relation to epidermal growth factor receptor and estrogen receptor

Growth fractions detected by a monoclonal antibody, Ki-67, were examined in 40 human breast cancer tissues and the results compared with the immunocytochemical reactivities of epidermal growth factor receptor (EGFR) and estrogen receptor (ER). The proportion of proliferating cells displaying Ki-67 positive staining was significantly higher in the EGFR positive tumors than in the EGFR negative tumors (p<0.01). The average percentage of Ki-67 positive cells in the EGFR positive tumors was 19.9 per cent, whereas that in the EGFR negative tumors was 8.0 per cent. By contrast, an inverse relationship between the proportion of proliferating cells and ER positive cells detected by anti-ER monoclonal antibody was observed. This data indicated the difference in growth fractions with relation to the EGFR and ER status of breast cancer.