Changes in third ventricular size with neuroendoscopic third ventriculostomy: a blinded study.
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The objective was to study the relation between changes in cerebral ventricular size and clinical outcome after neuroendoscopic third ventriculostomy (NTV) in both primary (no previous surgery) and secondary (previous CSF diversion for hydrocephalus) NTV. Changes in ventricular size were related to the need for further surgery for CSF diversion. A blinded retrospective study of the pre-NTV and post-NTV sizes of the ventricles in an unselected series of patients undergoing this procedure was done. A decrease in third ventricular size was seen in significantly more patients in the primary group than in the secondary group. Median change in third ventricle width for those who did not require further CSF diversion was significantly greater than those with no clinical benefit (p=0.01). Positive predictive power for successful outcome was highest for measures of the third ventricle; 73% and 68% for third ventricle width and height respectively, 88% for anterior to posterior commissure distance. In conclusion, third ventricular size reduces after NTV. The use of such a change as an arbiter of success in this procedure is questionable as clinically successful cases can have no change in ventricular size. It is considered that clinical outcome is the most important guide to success or failure as reduction in ventricular size is by no means guaranteed. Radiological outcomes alone may be misleading and reliance on them should be avoided. (+info)
Chronic central leptin infusion restores hyperglycemia independent of food intake and insulin level in streptozotocin-induced diabetic rats.
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We examined the effects of chronic centrally administered leptin on the glucose metabolism of streptozotocin-induced diabetic (STZ-D) rats, a model for insulin-dependent diabetes mellitus. When 3 microg.rat(-1).day(-1) of leptin was infused into the third ventricle for 6 consecutive days (STZ-LEP), STZ-D rats became completely euglycemic. The effect was not seen when the same dosage was administered s.c. Centrally administered leptin did not affect peripheral insulin levels. The feeding volume of STZ-LEP rats was suppressed to the level of non-STZ-D control rats. No improvement of hyperglycemia was noted when STZ-D rats were pair-fed to match the feeding volume of STZ-LEP rats. Thus, the euglycemia of STZ-LEP rats cannot be due to the decreased feeding volume. In the STZ-D rat, glucokinase mRNA, a marker of glycolysis, is down-regulated whereas glucose-6-phosphatase mRNA, a marker of gluconeogenesis, and glucose transporter (GLUT) 2, which is implicated in the release of glucose from liver, are up-regulated. GLUT4, uncoupling protein (UCP) 1, and UCP3 were down-regulated in brown adipose tissue. These parameters returned to normal upon central infusion of leptin. GLUT4 was not down-regulated in the skeletal muscle of STZ-D rats; however, fatty acid binding protein and carnitine palmitoyltransferase I, markers for utilization and beta-oxidation of fatty acids, were up-regulated and restored when the rats were treated with leptin. The increase and subsequent decrease of fatty acid utilization suggests a decrease of glucose uptake in the skeletal muscle of STZ-D rats, which was restored upon central leptin administration. We conclude that centrally infused leptin does not control serum glucose by regulating feeding volume or elevating peripheral insulin, but by regulating hepatic glucose production, peripheral glucose uptake, and energy expenditure. The present study indicates the possibility of future development of a new class of anti-diabetic agents that act centrally and independent of insulin action. (+info)
Forebrain-mediated adaptations to myocardial infarction in the rat.
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Recent studies suggest that the forebrain contributes to the circulatory derangements leading to heart failure after myocardial injury. We tested that hypothesis by examining the effect of myocardial infarction (MI) or sham MI (MI-s) on neurohumoral regulation in rats with prior anteroventral (AV) third ventricle lesion (AV3V-x) or sham lesion (AV3V-s). AV3V-s/MI rats had higher sodium intake, lower urine volume, and lower urinary sodium excretion than AV3V-s/MI-s rats. AV3V-x/MI rats had lower sodium intake and higher urine volume than AV3V-s/MI or AV3V-s/MI-s rats and urinary sodium excretion comparable to AV3V-s/MI-s rats. AV3V-x had no effect on baseline plasma renin activity (PRA). One week after MI, PRA had increased in AV3V-s but decreased in AV3V-x rats. AV3V-x reduced renal sympathetic nerve activity in MI and MI-s rats. AV3V-x improved baroreflex function in MI rats but diminished it in MI-s rats. Survival beyond 2 wk was lower in the AV3V-x/MI rats than in all other groups. These results confirm a critical role for the forebrain in the neurohumoral adjustments to MI. (+info)
Effect of endoscopic third ventriculostomy on neuropsychological outcome in late onset idiopathic aqueduct stenosis: a prospective study.
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OBJECTIVE: To undertake a prospective study of the long term neuropsychological outcome in patients with late onset idiopathic aqueduct stenosis (LIAS) after endoscopic third ventriculostomy. METHODS: Six patients with LIAS were evaluated pre- and postoperatively using magnetic resonance imaging (MRI) and standardised psychometric testing procedures. Endoscopic third ventriculostomy was done using standard surgical techniques. The mean long term follow up was 81.2 weeks. RESULTS: Preoperatively, all patients had cognitive impairment, four of them showing deficits in several cognitive domains. After endoscopic third ventriculostomy, all patients improved clinically and had ventricular size reduction on MRI. Postoperative neuropsychological testing showed that five patients achieved normal or near normal cognitive functions, and one improved moderately. CONCLUSIONS: Endoscopic third ventriculostomy caused a substantial improvement in the neuropsychological deficit of LIAS patients. This was also true for patients with enlarged ventricles that might be diagnosed radiologically as "arrested hydrocephalus." (+info)
Third ventriculostomy through the lamina terminalis for intracranial pressure monitoring after aneurysm surgery: technical note.
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OBJECTIVE: A new ventriculostomy technique through the lamina terminalis is described. This technique is applied mainly during aneurysm surgery at the acute stage. METHOD: Thirteen patients were operated on intracranial aneurysms and, during the procedure, had the lamina terminalis fenestrated. A ventricular catheter was inserted into the third ventricule, left in place and connected to an external drainage system for further intracranial pressure (ICP) monitoring and/or cerebrospinal fluid (CSF) drainage. RESULTS: ICP readings and CSF drainage were obtained in all cases. No complication was recorded. CONCLUSION: Third ventriculostomy through the lamina terminalis is a simple and easy technique that can be used as an alternative to conventional ventriculostomy. This procedure can be indicated in cases where the ventricule is not reached by means of another technique, and when the decision to perform ventriculostomy is made at the end of aneurysm surgery. (+info)
Choroid plexus papilloma and Aicardi syndrome: case report.
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A case of Aicardi syndrome associated with a choroid plexus papilloma of the third and both lateral ventricles in a 15 months old baby girl is repported. The tumor was completely removed via three craniotomies. Reports of the literature with the association of choroid plexus papilloma and Aicardi syndrome are rare. We suggest that children diagnosed with Aicardi syndrome should routinely undergo imaging studies of the brain, such as computed tomography or magnetic resonance. (+info)
Endoscopic third ventriculostomy in obstructed hydrocephalus.
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Forty-three ETV were performed in 46 patients of obstructive hydrocephalus. Study was divided into two groups. Group 1 was with 29 children of less than two years age. Group 2 had seventeen patients of more than 2 years, adolescent and adults. Group 1 had 70% clinical and 63% radiological improvement whereas Group 2 showed 100% clinical and 73% radiological improvement. ETV failed in relieving the symptoms of hydrocephalus in eight patients. They were eventually benefited with VP Shunt. There was one postoperative death, which was not related to the procedure. ETV is an important alternative to VP Shunt in relieving hydrocephalus due to obstruction in CSF pathway. (+info)
Hyperphagic effects of brainstem ghrelin administration.
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The role of ghrelin in feeding control has been addressed from a largely hypothalamic perspective, with little attention directed at ingestive consequences of stimulation of the peptide's receptor, the growth hormone secretagogue receptor (GHS-R), in the caudal brainstem. Here, we demonstrate a hyperphagic response to stimulation of GHS-R in the caudal brainstem. Ghrelin (150 pmol) delivered to the third and fourth ventricles significantly and comparably increased cumulative food intake, with maximal response approximately 3 h after injection. The meal patterning effects underlying this hyperphagia were also similar for the two placements (i.e., significant reduction in the time between injection and first-meal onset, an increase in the number of meals taken shortly after the injection, and a trend toward an increase in the average size of the first meals that approached but did not achieve statistical significance). In a separate experiment, ghrelin microinjected unilaterally into the dorsal vagal complex (DVC) significantly increased food intake measured 1.5 and 3 h after treatment. The response was obtained with a 10-pmol dose, establishing the DVC as a site of action with at least comparable sensitivity to that reported for the arcuate nucleus. Taken together, the results affirm a caudal brainstem site of action and recommend further investigation into multisite interactions underlying the modulation of ingestive behavior by ghrelin. (+info)