Neuronal activity in the globus pallidus of multiple system atrophy patients.

The pathophysiological changes in neural activity that characterize multiple system atrophy (MSA) are largely unknown. We recorded the activity of pallidal neurons in 3 patients with clinical and radiological features of MSA who underwent unilateral microelectrode-guided pallidotomy for disabling parkinsonism. Findings in these patients were compared with 4 control patients with a clinical diagnosis of Parkinson's disease (PD). The position, firing rates, and firing patterns of single neurons in the pallidal complex were analyzed in both MSA and PD patients. The mean spontaneous firing rate of neurons in the internal segment of the globus pallidus internus (GPii) was significantly lower in MSA than in PD patients. There were no significant differences between MSA and PD patients, however, in firing rates of neurons in the external globus pallidus (GPe) or in the external segment of GPi (GPie). In addition, no significant differences in firing pattern were found between MSA and PD patients. In conclusion, this study has shown that firing rates of neurons in GPii but not in GPie and GPe are different in MSA patients compared with that in PD patients, a finding that may reflect the poor clinical results of pallidotomy reported in patients with MSA.     

Changes in diastolic function in heart rejection: role of Doppler echocardiography]

In acute cardiac rejection, left ventricular diastolic function is altered. To study these abnormalities and their utility in cardiac allograft rejection, we studied 56 cardiac transplant recipients. All patients were assessed with endomyocardial biopsy and Doppler echocardiography done in the same day. A total of 163 Doppler studies were recollected. Cardiac transplant recipients were excluded during the early 6 weeks postoperative period. Totally, 100 biopsies were normal, 48 positive for mild rejection (Billingham Gde I-II) and 15 positive for moderate or severe rejection (Billingham Gde III-IV). Compared to negative biopsies, during acute rejection left ventricular wald thickness significantly increased (p < 0.05); isovolumic relaxation period and pressure half-time significantly decreased (p < 0.05, p < 0.001 respectively). Nevertheless, increase in peak early mitral flow velocity was only significantly associated with severe rejection (p < 0.001). Correlating only progressive shortening of isovolumic relaxation period parameter in the diagnosis of graft rejection, we forward a high sensibility (85%) and low specificity (57%). Thus, Doppler echocardiographic evaluation of left ventricular diastolic function provides a non-invasive tool for early detection of acute rejection monitoring after the early postoperative period.     

Normalized protein catabolic rate versus serum albumin as a nutrition status marker in pediatric patients receiving hemodialysis.

BACKGROUND: Protein-energy malnutrition occurs commonly in patients receiving hemodialysis (HD). Although serum albumin (sAlb) is recommended to monitor nutrition status in patients receiving HD, many processes unrelated to nutrition status can affect albumin concentrations. METHODS: We previously showed normalized protein catabolic rate (nPCR) to be superior to sAlb to reflect improvement in nutrition status in pediatric patients receiving maintenance HD after treatment with intradialytic parenteral nutrition for severe protein-energy malnutrition. We now compare nPCR and sAlb as nutrition status markers for pediatric patients on HD irrespective of current nutrition status. RESULTS: Forty-four patients comprising 840 months of HD provision were assessed. nPCR was higher for younger patients. Mean nPCR values were significantly lower for adolescent patients with persistent weight loss of at least 2% for at least 3 consecutive months versus patients without persistent weight loss (1.03 +/- 0.29 g/kg/d vs. 1.15 +/- 0.27 g/kg/d, P < .002), and the odds for developing persistent weight loss were four times greater for adolescent patients with nPCR less than 1 g/kg/d. No association between nPCR and weight loss was observed for younger patients. Mean sAlb levels were greater than 4 g/dL for all patient age groups and did not demonstrate a clinically significant difference between patients with or without weight loss. CONCLUSION: We suggest that nPCR may be useful for monthly nutrition status in adolescent patients receiving maintenance HD and that adolescents with nPCR less than 1 g/kg/d may be at increased risk for subsequent weight loss.     

Thrombelastographic measures of clot propagation: a comparison of alpha with the maximum rate of thrombus generation.

The alpha angle alpha (degrees) is a thrombelastographic measure of clot propagation. A parametric measurement of clot propagation [maximum rate of thrombus generation (MRTG), dynes/cm2 per s], however, has recently been utilized. Thus, the relationship of changes in alpha with changes in MRTG were determined. alpha and MRTG values obtained from 859 thrombelastograms was collected from nine studies. Data were analyzed and the relationship between alpha and MRTG defined with commercially available software. Additional comparisons were made retrospectively from whole-blood and plasma data obtained from 33 normal individuals. Data from the nine studies demonstrated that MRTG increased in an exponential fashion compared with increases in alpha (R2 = 0.88, P < 0.001). Whole-blood alpha values were in the range 66.7-74.7 whereas MRTG values were 5.5-10.8, and plasma alpha values were 65.1-77.9 with corresponding MRTG values of 3.5-12.0. Assessment of clot propagation utilizing MRTG provides a more parametric evaluation than the determination of alpha. While normal alpha values may vary by only 12-20%, MRTG values vary by approximately 200-300%. The MRTG should be progressively utilized to a greater extent in both laboratory and clinical settings to parametrically quantify clot growth kinetics with thrombelastography.     

Deep brain stimulation for Parkinson's disease dissociates mood and motor circuits: a functional MRI case study.

Behavioral disturbances have been reported with subthalamic (STN) deep brain stimulation (DBS) treatment in Parkinson's disease (PD). We report correlative functional imaging (fMRI) of mood and motor responses induced by successive right and left DBS. A 36-year-old woman with medically refractory PD and a history of clinically remitted depression underwent uncomplicated implantation of bilateral STN DBS. High-frequency stimulation of the left electrode improved motor symptoms. Unexpectedly, right DBS alone elicited several reproducible episodes of acute depressive dysphoria. Structural and functional magnetic resonance imaging (fMRI) imaging was carried out with sequential individual electrode stimulation. The electrode on the left was within the inferior STN, whereas the right electrode was marginally superior and lateral to the intended STN target within the Fields of Forel/zona incerta. fMRI image analysis (Analysis of Functional NeuroImages, AFNI) contrasting OFF versus ON stimulation identified significant lateralized blood oxygen level-dependent (BOLD) signal changes with DBS (P < 0.001). Left DBS primarily showed changes in motor regions: increases in premotor and motor cortex, ventrolateral thalamus, putamen, and cerebellum as well as decreases in sensorimotor/supplementary motor cortex. Right DBS showed similar but less extensive change in motor regions. More prominent were the unique increases in superior prefrontal cortex, anterior cingulate (Brodmann's area [BA] 24), anterior thalamus, caudate, and brainstem, and marked widespread decreases in medial prefrontal cortex (BA 9/10). The mood disturbance resolved spontaneously in 4 weeks despite identical stimulation parameters. Transient depressive mood induced by subcortical DBS stimulation was correlated with changes in mesolimbic cortical structures. This case provides new evidence supporting cortical segregation of motor and nonmotor cortico-basal ganglionic systems that may converge in close proximity at the level of the STN and the adjacent white matter tracts (Fields of Forel/zona incerta).     

Reduction of plasma insulin levels does not restore integrated concentration of growth hormone to normal in obese children.

Obesity in childhood is characterized by subnormal integrated concentrations of growth hormone (IC-GH) and elevated integrated concentrations of insulin (IC-I). We tested whether a reduction of IC-I induced by a low calorie diet would lead to a rise of IC-GH into the normal range for age. Six obese children (body mass index (BMI) 39.1 +/- 9.2 kg/m2) underwent integrated concentration (IC) studies by continuous withdrawal before and again 5-8 weeks after being on a low calorie diet. In response to the diet BMI was lower 34.7 +/- 9.4 kg/m2 (P less than 0.003), and IC-I was considerably reduced, 479 +/- 255 pM initially vs. 109 +/- 109 pM on the diet, P less than 0.0008. IC-GH increased modestly from 1.6 +/- 0.6 micrograms/l initially to 2.4 +/- 0.6 micrograms/l, P less than 0.01 on the diet. None of the patients had repeat IC-GH levels which were above the lower limit of normal for lean children of normal stature (3.2 micrograms/l). Single sample insulin-like growth factor 1 (IGF-1) levels were unchanged: 40.9 +/- 23.1 nM initially vs. 49.7 +/- 25.7 nM (314.6 +/- 197.7 vs. 382.5 +/- 217.0 ng/ml, n.s.). Thus reduction of high insulin concentrations during 5-8 weeks of a low calorie diet has only a small effect on IC-GH in obese children. Factors other than circulating insulin levels are likely to play the major role in mediating the reduced levels of GH observed in obesity.     

Bromazepam-induced dystonia.

Benzodiazepines are drugs with a good tolerance that are widely used for the treatment of anxiety. Extrapyramidal side-effects are unusual. Diazepam is effective for the treatment of drug-induced dystonias, nevertheless there are some reports of Diazepam-induced dystonia. We report a case history of a patient who developed oromandibular dystonia after taking Bromazepam. The possible mechanisms that cause drug-induced dystonia are described.     

Metabolic disorders in survivors of myocardial infarct

Several lines of evidence have clearly established the role of lipoproteins as risk factors for the development of atherosclerosis. Epidemiologic studies from different countries have found that about one third of myocardial infarction survivors under 60 years of age are hyperlipidemic. The acute stress reaction occurring in the first hours following an acute myocardial infarction causes distinct changes in the patient's metabolic profile, these changes include a significant reduction of total cholesterol and cholesterol associated with low density lipoproteins and a usually mild elevation of blood glucose. With the purpose of establishing the prevalence and severity of lipoprotein disorders found in myocardial infarction survivors living in Mexico city we conducted a prospective study of 106 consecutive admissions to the coronary care unit at the National Institute of Cardiology with the fully proven diagnosis of acute myocardial infarction, we included only patients younger than 60 years of age that could be sampled within the first 72 hours of the appearance of typical symptoms, at this time the coronary risk factor profile was assessed and blood samples were drawn (acute sample). After three months of the diagnosis we sampled 81 of the original 106 patients (chronic sample). The comparison of these 81 patients showed remarkable differences in the lipid values obtained on each sample. The mean value for total cholesterol in the acute sample was 225 mg/dl whereas the corresponding value for the chronic sample was 240.5 mg/dl (p less than 0.005). This difference was also highly significant for the low density fraction. On the basis of the chronic sample analysis we estimated a prevalence of hyperlipoproteinemia of 35.8%. (II: 18.5%, III: 2.5%, IV: 14.8%), an additional subgroup of 10 patients (12.3%) had the hypo-HDL phenotype raising the number of subjects at risk for atherosclerosis to as high as 48.1% considering only the lipoproteins. The prevalence figures for the rest of the risk factors were as follows: 70.3% for tobacco smoking, 35.8% for Systemic Arterial Hypertension, 33.4% for Obesity and 30.8% for Diabetes Mellitus. Among the group of 81 patients, 17 were known diabetics, eight additional cases of Diabetes Mellitus were diagnosed at the chronic phase (two with fasting hyperglycemia and six with diagnostic oral glucose tolerance tests). The "acute plase" glycemia for these eight subjects was significantly higher (mean: 98.4 mg/dl) than the corresponding value for the non diabetic patients (mean: 83.4 mg/dl p less than 0.002), the seventeen known diabetics had a mean glycemia of 150.6 mg/dl in the acute sample.(ABSTRACT TRUNCATED AT 400 WORDS)