[Manipulation of mental competence: an ethical problem in case of electrical stimulation of the subthalamic nucleus for severe Parkinson's disease].
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Biomedical subjects
Publications and source records attributed to P P de Deyn.
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To prevent extubation, nasogastric tubes (NGT) were attached to a fine bore polyurethane tube, which loops loosely around the nasal septum. In a prospective study 180 cases were evaluated concerning the efficacy and possible complications related to this techniques. On average, a nasal septal loop (NSL) remained 20.1 +/- 1.3 days and a NGT 14 +/- 0.9 days. Complications were rare. In 45 of the cases NGT had to be replaced after self extubation and in 2.2% extubation presented more than twice. We think NSL is an easy and useful technique to secure NGT in non-cooperative and/or agitated patients for a relatively short term enteral nutrition or gastric decompression.
UNLABELLED: Dementia of the Alzheimer's type [(S)DAT] and dementia with frontal features (FLD) are nosological entities with different prognoses and presumed pathophysiology. There is a need for noninvasive differential diagnostic tools. To evaluate whether SPECT perfusion imaging could discriminate between these neurodegenerative disorders, we performed a comparative study. METHODS: SPECT scans using 99mTc-hexamethylpropylene amine oxime (99mTc-HMPAO) of 21 patients with FLD were compared with those obtained in a group of 19 age- and severity-matched patients suffering from (S)DAT. Brain SPECT perfusion deficits were scored by visual qualitative analysis with respect to location, lateralization and severity. A total severity score of cerebral hypoperfusion (maximal value = 18) was calculated by adding all severity scores (scored between 0 and 3; 0 = no perfusion deficit; 1 = 13%-30% hypoperfusion; 2 = 30%-50%, hypoperfusion and 3 = > 50% hypoperfusion including breaching of the cortex) for right and left frontal, parietal and temporal lobes. Moreover, bifrontal hypoperfusion (Fa) was scored, yielding a value between 0 and 6 by adding the two frontal severity scores. RESULTS: No significant correlation was found between MMSE scores and total severity scores on SPECT. A statistically significant correlation was found between the Middelheim frontality score and frontal severity score. Statistically more significant bilateral hypoperfusion of the parietal lobes was found in the (S)DAT group. Conversely, bifrontal hypoperfusion was found more in the FLD group. Stepwise logistic regression analysis identified the severity of bifrontal hypoperfusion as the most significant contributing parameter to correctly classifying (S)DAT versus FLD on SPECT. The probability of predicting (S)DAT based on the SPECT scan is calculated with the following formula: [equation: see text] Using this equation, a value above 0.5 was predictive for (S)DAT and a calculated value under 0.5 was predictive for FLD. Using this model, 81% of the FLD group and 74% of the (S)DAT were correctly classified. CONCLUSION: Technetium-99m-HMPAO SPECT may help in discriminating FLD from (S)DAT. Bifrontal hypoperfusion was found to be the most powerful predictor of clinical classification. Further validation of the presented logistic regression model is warranted.
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In traditional Chinese medicine, a mixture of radish and pepper is used to treat epilepsy. The presumptive effectiveness of this prescription might be due to the anticonvulsant actions of the principal component of pepper, the alkaloid piperine (CAS 94-62-2). The effects of piperine on convulsions induced in mice by agonists at different excitatory amino acid receptor subtypes were studied. Piperine was shown to significantly block convulsions induced by intracerebroventricular injection of threshold doses of kainate, but to have no or only slight effects on convulsions induced by L-glutamate, N-methyl-D-aspartate or guanidinosuccinate. Piperine suspensions, injected intraperitoneally, 1 h before injection of the threshold intracerebroventricular dose of kainate for the induction of clonic convulsions (1 nmol), blocked these convulsions with an ED50 (and 95% confidence interval) of 46 (25-86) mg/kg. Although piperine did block convulsions, induced by kainate, the compound does not appear to act as a kainate receptor antagonist. Whole-cell currents induced by the application of kainate to spinal cord cells in primary dissociated cultures were not affected by co-application of piperine.
In mammalian kidney, the proximal convoluted tubule (PCT) is the main site of arginine (Arg) production. Arginine can be used in the biosynthesis of guanidino compounds (GC). Since uremic rats have a lower functional mass of PCT, GC synthesis might be modified, especially that of guanidinoacetic acid (GAA) which occurs in PCT. In order to study GC metabolism at different steps of uremia, rats were subjected to either 42% or 80% nephrectomy (NX); the experiment lasted for three weeks. Results show that: (1) in plasma, the pattern of GC levels in 42% NX rats was similar to that of controls except for a clear increase of beta-guanidinopropionic acid (beta-GPA), whereas in 80% NX rats, all GC levels sharply increased except that of creatine which decreased. (2) Urinary excretion of GC in control and 42% NX rats is quite similar except for GAA which strongly decreased, and for homoarginine (HArg) and argininic acid (ArgA) which increased. In rats with 80% NX, the principal modification in GC excretion was a four- to five-fold reduction in GAA output. (3) After induction of renal failure, Arg, creatine and guanidinosuccinic acid reabsorption remained unchanged, and that of HArg decreased. For guanidine and methylguanidine the negative renal balance remained unchanged, and that of gamma-guanidinobutyric acid, GAA and alpha-keto-delta-guanidinovaleric acid became smaller, suggesting a better reabsorption. In conclusion, uremia strongly modified GC metabolism involving mainly those synthesized from Arg; both GAA and creatine synthesis were strongly decreased probably because of the loss of renal tissue, mainly PCT.
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A 30-year-old woman developed multiple cerebral infarctions. In the absence of other risk factors, thrombocythemia secondary to iron deficiency anemia due to polymenorrhoea was considered to underlie the cerebral infarctions. Platelet count was normalized after iron therapy. The importance of vigorous treatment of iron deficiency anemia in preventing complications of secondary thrombocythemia is emphasized.
Pentachlorophenol (PCP) is a widely applied insecticide and fungicide, particularly in wood preservation. Significant amounts of this compound have been reported in human serum, adipose tissue and urine. PCP is even found in people not occupationally exposed to this toxin or not living in PCP-treated log-houses. Substantial concentrations of this possible neurotoxic agent were detected in the cerebrospinal fluid (CSF) of 16 neurologic patients as measured by a high resolution gas chromatographic method using electron capture detection. This is the first report on PCP levels in (human) CSF. The observed level in CSF ranged from 0.24 up to 2.03 micrograms/L (ppb), with an average value of 0.75 +/- 0.49. The cerebrospinal fluid level did not correlate with the serum PCP concentration nor with the protein level of the cerebrospinal fluid.
Several neuropeptides have been demonstrated to coexist with classical neurotransmitters in the central and peripheral nervous systems and have been proposed as neurotransmitter or neuromodulator candidates. In this report, we investigated the relationship between the external calcium concentration and the electrically induced overflow of noradrenaline (NA) and neuropeptide Y (NPY) in dog perfused spleen. Perfusion solutions with calcium concentrations ranging from 0 to 10 mM were applied. The splenic nerves were electrically stimulated at 16 Hz. For NA analysis high-pressure liquid chromatography with electrochemical detection was used. NPY was determined by radioimmunoassay. The perfusion pressure and the overflow of NA and NPY increased in a calcium concentration dependent manner. The calcium concentration dependency of the overflow of NA and NPY was comparable, indicating a co-release of the two substances. The molar ratio of NA/NPY remained unchanged over the calcium concentration range applied and the half maximal saturation values for release of NA (5.55 mM) and NPY (6.66 mM) were similar. These results indicate that the preferential release of NPY at high frequency stimulation as previously shown in the pig spleen, if present in the dog, is not the result of a difference in calcium dependency of the evoked release of NA and NPY.