Noninvasive Thermal Evaluation of Ventriculoperitoneal Shunt Patency and Cerebrospinal Fluid Flow Using a Flow Enhancing Device.

BACKGROUND: While a noninvasive flow determination would be desirable in the diagnosis of cerebrospinal fluid shunt malfunction, existing studies have not yet defined a role for thermal flow detection. OBJECTIVE: To evaluate a revised test protocol using a micropumper designed to transiently enhance flow during thermal testing to determine whether thermal detection of flow is associated with progression to shunt revision surgery. METHODS: Eighty-two unique tests were performed in 71 shunts. The primary outcome, need for revision within 7 d of testing, was compared with results of micropumper-augmented thermal flow detection. Statistical analysis was based on blind interpretation of test results and raw temperature data recorded during testing. RESULTS: The test was sensitive (73%) and specific (68%) in predicting need for revision, with 5.6-fold higher probability of revision when flow was not detected. Negative predictive value in our sample was 94.2%. The probability of not requiring revision increased with increasing total temperature drop. Analysis of various possible thresholds showed that the optimal temperature cutoff may be lower than suggested by the manufacturer (0.125°C vs 0.2°C). CONCLUSION: This is the first study to report a strong association between thermal flow evaluation and a clinical impression that a shunt is not malfunctioning. The current recommended threshold may increase the false positive rate unnecessarily, and as clinicians gain experience with the method, they may find value in examining the temperature curves themselves. Multicenter studies are suggested to further define a role for this diagnostic test.

Nitric oxide modulates the amphetamine effect on [3H]glucose uptake in the brain of rats prenatally exposed to lead.

Glucose is the main source of energy for the central nervous system (CNS). In this study, we examined the effects of the psychostimulant amphetamine (AMPH) and the neuronal mediator nitric oxide (NO) on [3H]glucose uptake in the brain of adult rats that had been prenatally exposed to lead. Lead [Pb(CH3COO)2 . 3H2O; 250 ppm] was added to the drinking water of pregnant Wistar rats for the duration of pregnancy. On the day of parturition, lead was discontinued as an additive in the drinking water. Offspring remained ith dams for 21 days. The control group consisted of rats that consumed water without lead. In adulthood, male offspring from both groups (lead-exposed and control) were pretreated with 7-nitroindazole (nNOS blocking agent) (10.0 mg/kg ip) or saline (1.0 ml/kg ip), 30 min before AMPH (1.0 mg/kg ip). After another 30 min, and 15 min before termination, all rats were injected with 6-[3H]-D-glucose (500 muCi/kg ip). Brain specimens were taken (striatum, frontal cortex, hippocampus, and thalamus with hypothalamus, and pons with medulla oblongata) for determination of radioactivity in a liquid scintillation counter. We found that lead did not alter [3H]glucose uptake in brain regions studied (with exception of frontal cortex) but that AMPH increased [3H]glucose uptake in the striatum, frontal cortex and hippocampus, and that the AMPH effect was lessened in the hippocampus of lead-exposed rats. Moreover, the AMPH effect on [3H]glucose uptake in the frontal cortex, hippocampus, thalamus with hypothalamus and pons of control rats was potentiated by 7-NI pretreatment. Similar effect was observed in lead-intoxicated rats (striatum, frontal cortex and hippocampus). These results indicate that NO modulates AMPH-induced [3H]glucose uptake in the brain of rats prenatally exposed to lead.

Central effects of nafadotride, a dopamine D3 receptor antagonist, in rats. Comparison with haloperidol and clozapine.

The aim of this study was to examine behavioral and biochemical effects of nafadotride, the new dopamine D3 receptor antagonist, and to compare it with haloperidol (dopamine D2 receptor antagonist) and clozapine (predominate dopamine D4 receptor antagonist). Each drug was injected to adult male Wistar rats intraperitoneally, each at a single dose and for 14 consecutive days. Thirty minutes after single or last injection of the examined drugs, the following behavioral parameters were recorded: yawning, oral activity, locomotion, exploratory activity, catalepsy and coordination ability. By HPLC/ED methods, we determined the effects of the examined antagonists on the levels of biogenic amines in striatum and hippocampus: dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3-methoxytyramine (3-MT), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and noradrenaline (NA). Additionally, DA and 5-HT synthesis rate was determined in striatum and 5-HT in hippocampus. The results of the study indicate that nafadotride, the dopamine D3 receptor antagonist, has a behavioral and biochemical profile of action different from that of haloperidol but partially similar to that of clozapine.