ATP-Sensitive Potassium Channel-Deficient Mice Show Hyperphagia but Are Resistant to Obesity

BACKGROUND: The hypothalamus, the center for body weight regulation, can sense changes in blood glucose level based on ATP-sensitive potassium (KATP) channels in the hypothalamic neurons. We hypothesized that a lack of glucose sensing in the hypothalamus affects the regulations of appetite and body weight. METHODS: To evaluate this hypothesis, the responses to glucose loading and high fat feeding for eight weeks were compared in Kir6.2 knock-out (KO) mice and control C57BL/6 mice, because Kir6.2 is a key component of the KATP channel. RESULTS: The hypothalamic neuropeptide Y (NPY) analyzed one hour after glucose injection was suppressed in C57BL/6 mice, but not in Kir6.2 KO mice, suggesting a blunted hypothalamic response to glucose in Kir6.2 KO mice. The hypothalamic NPY expression at a fed state was elevated in Kir6.2 KO mice and was accompanied with hyperphagia. However, the retroperitoneal fat mass was markedly decreased in Kir6.2 KO mice compared to that in C57BL/6 mice. Moreover, the body weight and visceral fat following eight weeks of high fat feeding in Kir6.2 KO mice were not significantly different from those in control diet-fed Kir6.2 KO mice, while body weight and visceral fat mass were elevated due to high fat feeding in C57BL/6 mice. CONCLUSION: These results suggested that Kir6.2 KO mice showed a blunted hypothalamic response to glucose loading and elevated hypothalamic NPY expression accompanied with hyperphagia, while visceral fat mass was decreased, suggesting resistance to diet-induced obesity. Further study is needed to explain this phenomenon.

An Intramedullary Neurenteric Cyst in the Conus Medullaris with Recurrent Meningitis

Neurenteric cysts are rare congenital lesions of the spine that are lined with endodermal epithelium. Their most common location is the cervico-dorsal region, and the mass usually lies ventral to the spinal cord. However the conus medullaris area location is an uncommon location. Neurenteric cysts are best treated by decompression and as near total excision of cyst membrane as possible. We report a case of a 7 year-old-girl with a neurenteric cyst in the conus medullaris. The patient had a history of meningitis and a gait disturbance. Magnetic resonance imaging (MRI) showed an intramedullary mass lesion in the conus medullaris with syringomyelia. There was no associated bone or soft-tissue anomaly. The mass was subtotally removed through a posterior approach. However 4 months later, meningeal irritation signs developed and MRI showed recurrence of the cyst. At the second operation, the cystic membrane was totally removed and the patient's neurological symptoms improved postoperatively. We reports a case of recurred neurenteric cyst occurred in unusual location with the review of literature.

Microsurgical Selective Obturator Neurotomy for Spastic Hip Adduction

OBJECTIVE: Cerebral palsy may induce harmful spastic hip adduction. We report the result of microsurgical selective obturator neurotomy, performed on 12 spastic hip adductions of 6 patients, followed clinically for at least 26 months postoperatively. METHODS: Microsurgical selective obturator neurotomies, involving microsurgical resection of the anterior obturator nerve branches were performed on 6 patients from January 2000 through June 2003. All patients presented with the inability to sit and 2 patients complained of persistent, intractable pain. We used intraoperative bipolar stimulation to identify selected motor branches. RESULTS: The procedure was performed bilaterally in all patients. In the 3 patients in whom contractures were present, microsurgical selective obturator neurotomies were accompanied by an additional tenotomy of the adductor muscles. Selective tibial neurotomy was performed on three of six patients who originally presented with a spastic ankle. Postoperatively, all spastic hip adductions were corrected more than 60 degrees in passive abduction-adduction amplitude. However, one patient who did not receive active postoperative physiotherapy demonstrated a decreased passive abduction-adduction amplitude upon follow-up. There were no surgical complications. CONCLUSION: We think microsurgical selective obturator neurotomy may be an effective procedure in the treatment of localized, harmful spastic hip adduction after failure of well conducted conservative treatment. As muscular contractions are often associated with spasticity of the hip adductors, an adjunctive tenotomy may be an option. Comprehensive postoperative physiotherapy is essential to improve long-term results.

Long Term Results of Microsurgical Dorsal Root Entry Zonotomy for Intractable Pain Associated with Brachial Plexus Injury

OBJECTIVE: Brachial plexus injury can produce a intractable chronic neuropathic pain. This study was undertaken to assess the long term outcome of microsurgical dorsal root entry zonotomy(MDT). METHODS: Between October 1997 and December 2002, 21 patients received MDT because of a intractable pain resulting from brachial plexus injury. Of these, 19 patients were followed for more than 2 years. Fourteen of 19 patients were male and patient ages ranged from 22 to 69 years. Mean pain duration was 36.8 months and all patients had severe pain of 9~10 visual analogue scale. To achieve complete destruction of abnormal dorsal horns, thermocoagulation of the posterolateral sulcus were performed and careful gluing was done to prevent postoperative adhesion and pain recurrence. RESULTS: Of the 19 patients, 15 patients had excellent (>75% reduction in pain) and good (51~75% pain relief) results in a average postoperative period of 4.1 years. One patient had a poor (less than 25% pain relief) result. Three patients were considered to have a fair result (26~50% pain relief). Postoperative complications were 2 transient ipsilateral ataxia and 1 CSF fistula that resolved without surgical revision. CONCLUSION: These results indicate that MDT provides excellent long-term pain relief in medically intractable chronic neuropathic pain following brachial plexus injury without significant complications.