Large-scale microarray gene expression analysis in discrete electrophysiologically identified neuronal clusters

The normal processes of learning and memory as well as the pathological progress of various neurological diseases may result in changes in gene expression in small, local populations of neurons in any given brain area, leading to the occurrence of specific patterns of electrical activity without easily detectable changes in the morphology of this brain area. One way of identifying these changes might be the comparison of gene expression of areas which generate and areas which do not generate specific patterns of electrical activity. A method for microbiopsy of limited (0.5-1.0 mm3) tissue samples from electrophysiologically identified areas of neurons generating epileptiform activity in the rat brain is described. Here we demonstrate that total RNA isolated from individual microbiopsy samples might be successfully used for microarray based gene expression analysis of any discretely localized neuronal group which can be identified electrophysiologically, including neurons in cortical columns, cell assemblies or other functional units.     

Acute peripheral facial palsy in Lyme disease -- a distal neuritis at the infection site

AIM: Children with acute peripheral facial palsy have often suffered tick bites and/or erythema migrans in the head/neck region on the same side. With respect to the pathogenesis of neuroborreliosis this topographical association was investigated in an animal model. METHODS: A Borrelia garinii strain, isolated from the CSF of a child with acute facial palsy, was injected in 9 rats intracutaneously in the right subauricular region. Infected rats were examined for clinical symptoms of Lyme disease, the spread of the spirochetes was investigated by PCR of necropsies (facial nerves, trigeminus nerves, heart, brain, skin) up to 47 days after infection. The nerve tissues were investigated by histology, immunohistochemistry and electron microscopy. RESULTS: None of the rats developed a facial palsy or other symptoms of Lyme disease. Borrelia DNA was found in the heart after 5 days and in the brain after 7 days of infection up to the end of investigation (47 days), as well as in the ipsilateral peripheral nerves after 7 to 33 days. Borrelia was detected by electron microscopy near endoneural vessels of the facial nerve. Peri-, epi-, and endoneural infiltrations of macrophages, plasma cells and B cells characterized an inflammation of the facial and trigeminus nerves ipsilateral to the infection site. CONCLUSION: An infection with Borrelia garinii in the subauricular region induces an ipsilateral neuritis of peripheral nerves. The particular vulnerability of the human facial nerve may be a result of its long intraosseus course. Thus, an inflammatory edema may injure the nerve in the canalis facialis.     

Blunted inhibition of return in schizophrenia-evidence from a longitudinal study

Previous cross-sectional studies on covert orienting of visual attention in schizophrenia have been inconsistent. In the present longitudinal study, we examined 40 medicated acutely ill inpatients with a covert orienting of attention task (COVAT) shortly after admission, and again 12-16 weeks after the initial examination, while most patients were in (partial) remission. We administered a COVAT with nonpredictive peripheral cues and two stimulus-onset asynchronies (SOA; 100 and 800 ms). In addition, we examined 34 healthy control subjects twice (2 weeks apart). The most important finding was a lack of inhibition of return (IOR) in patients with schizophrenia, both at the first examination in an acute psychotic state and at the follow-up examination after considerable clinical improvement. The IOR deficit was unrelated to psychopathology, length of illness, number of previous psychotic episodes, and type of neuroleptic (NL) medication. Deficient IOR in patients with schizophrenia appears to be state-independent and might be viewed as a trait or vulnerability marker of the disorder. Subsequent studies with never-medicated populations and with schizotypal or high-risk subjects are needed in order to further analyze the possible role of NL medications and to clarify whether blunted IOR might represent a vulnerability marker of schizophrenia.     

Platelet aggregation induced by the C-terminal peptide of thrombospondin-1 (4N1-1) is inhibited by epigallocatechin gallate but not by prostaglandin E1

The C-terminal peptide of thrombospondin (4N1-1) stimulates distinct signalling pathways but induces an activation-independent platelet aggregation. This study demonstrates inhibitory effects of epigallocatechin gallate (EGCG), a major flavonoid component of green tea, on 4N1-1-induced aggregation of washed human platelets. Thrombin (0.1 U/ml)-induced platelet aggregation was completely inhibited by prostaglandin E1 (PGE1, 300 nM). In contrast, platelet aggregation induced by 4N1-1 (100 microM) was not affected by PGE1. However, epigallocatechin gallate (EGCG), but not other catechins from green tea, concentration-dependently inhibited 4N1-1-induced platelet aggregation. Thus, dietary components, such as EGCG, may inhibit platelet function even under conditions, when 'classical' platelet inhibitors, such as cAMP-elevating agents, are not effective.     

Deep brain stimulation of the subthalamic nucleus improves cognitive flexibility but impairs response inhibition in Parkinson disease

BACKGROUND: Deep brain stimulation of the subthalamic nucleus (STN) improves motor symptoms of Parkinson disease. Although several studies have assessed cognitive functions before surgery and after long-term STN stimulation, only a few have assessed patients while stimulation is on and off to more specifically address the short-term cognitive effects of STN deep brain stimulation. OBJECTIVE: To examine the short-term effects of STN stimulation on several tests sensitive to executive function and the long-term effects of STN stimulation on a global cognitive scale. DESIGN: Twenty-three patients with Parkinson disease were tested 6 to 12 months after surgery with STN stimulation switched on and off in a random order while taking their regular medication. The Unified Parkinson's Disease Rating Scale motor score was also rated in the on and off stimulation condition. The neuropsychological battery included digit span, verbal fluency, Stroop color test, and random number generation in a single- and dual-task condition. RESULTS: Short-term stimulation improved the results on the Random Number Generation Task, requiring suppression of habitual responses, but induced more errors in the interference task of the Stroop color test. Digit span, verbal fluency, and dual-task performance results did not change. There was a significant correlation (r = 0.47, P =.02) between improved performance on the Random Number Generation Task and impaired response inhibition in the Stroop interference condition. A preoperative to postoperative comparison showed no changes in global cognitive function with long-term STN deep brain stimulation. CONCLUSIONS: Short-term STN stimulation improves cognitive flexibility (giving up habitual responses) but impairs response inhibition. Long-term STN stimulation does not change global cognitive function.     

De novo femoropopliteal stenoses: endovascular gamma irradiation following angioplasty--angiographic and clinical follow-up in a prospective randomized controlled trial

PURPOSE: To assess and report the follow-up results of a randomized controlled trial on centered endovascular gamma irradiation performed after percutaneous transluminal angioplasty (PTA) for de novo femoropopliteal stenoses. MATERIALS AND METHODS: Thirty patients who underwent PTA for de novo femoropopliteal stenoses were randomly assigned to undergo 14-Gy centered endovascular irradiation (irradiation group, n = 15) or no irradiation (control group, n = 15). Intraarterial angiography was performed 6, 12, and 24 months after treatment; duplex ultrasonography (US), the day before and after PTA and 1, 3, 6, 9, 12, 18, and 24 months later. Treadmill tests and interviews were performed the day before PTA and 1, 3, 6, 9, 12, 18, and 24 months later. Results of angiography, duplex US, treadmill tests, and interviews were evaluated with the nonpaired t or the Fisher exact test. RESULTS: Baseline characteristics did not differ significantly between the two groups. Mean absolute individual changes in degree of stenosis, compared with the degrees of stenosis shortly after PTA, in the irradiation group versus in the control group were -10.6% +/- 22.3 versus 39.6% +/- 24.6 (P <.001) at 6 months, -2.0% +/- 34.2 versus 40.6% +/- 32.6 (P =.002) at 12 months, and 7.4% +/- 43.2 versus 37.7% +/- 34.5 (P =.043) at 24 months. The rates of target lesion restenosis at 6 (P =.006) and 12 (P =.042) months were significantly lower in the irradiation group. The numbers of target lesion re-treatments were similar between the groups, but target vessel re-treatments were more frequent in the irradiation group. There were no significant differences in interview or treadmill test results between the two groups at t test analysis. CONCLUSION: The degree of stenosis was significantly reduced 6, 12, and 24 months after angioplasty of de novo femoropopliteal stenoses in the patients who underwent endovascular irradiation.     

In vivo voxel-based morphometry in multiple system atrophy of the cerebellar type

BACKGROUND: Multiple system atrophy (MSA) is a sporadic neurodegenerative disease. According to the clinical presentation a parkinsonian type and a cerebellar type (MSA-C) are distinguished. OBJECTIVE: To study the morphological alterations of MSA-C-affected brains in vivo using voxel-based morphometric analysis of magnetic resonance images. SETTING: University hospital. PATIENTS: Fourteen patients (5 men and 9 women) with MSA-C (mean age [SD], 59.4 [7.4] years; mean [SD] disease duration, 3.7 [1.4] years) and 13 healthy control subjects (5 men and 8 women) (mean [SD] age, 55.1 [6.9] years) were studied. METHODS: T1-weighted magnetic resonance images were normalized to a common stereotaxic space and segmented into gray and white matter. Data were analyzed using statistical parametric mapping (SPM99). RESULTS: Gray matter was reduced in the brainstem and the anterior lobe of the cerebellum. Reduction of white matter was observed in the middle cerebellar peduncles, cerebellar white matter, and brainstem. The inverted comparison revealed an increase of white matter density along the pyramidal tracts. CONCLUSIONS: Voxel-based morphometry revealed a significant loss of cerebellar and brainstem tissue in MSA-C. It allowed a precise anatomical localization and a distinction between gray and white matter densities. In addition, our data point to a particular involvement of the pyramidal tract in MSA-C.     

Trapidil protects ischemic hearts from reperfusion injury by stimulating PKAII activity

OBJECTIVE: The cardioprotective effects of trapidil on ischemic reperfused (I/R) rabbit hearts were studied. Recently, we had shown that trapidil might activate protein kinase A (PKA). In this study, we examined the exact mode of PKA stimulating activity of trapidil. Finally, we investigated the effect of trapidil on the phosphorylation state of phospholamban (PLB), a major PKA target in the heart and key regulator of Ca(2+) sequestration via the sarcoplasmic reticulum Ca(2+)-ATPase. METHODS: Langendorff-hearts of New Zealand White rabbits were perfused at constant volume and subjected to global low-flow ischemia for 2 h, followed by 1 h of reperfusion. Subsequently, hearts were used for Western blot analysis of PLB phosphorylation. Furthermore, three different regulatory subunits and one catalytic subunit of PKA were overexpressed in E. coli. These PKA subunits were purified and used in an in vitro assay system to test the impact of trapidil on PKA activities in the absence and presence of cAMP. RESULTS: I/R resulted in a significant increase in left ventricular end-diastolic pressure and creatine kinase efflux in the hearts. Trapidil (10 microM) prevented these alterations. Using recombinant cAMP-free PKA isoforms, it was found that trapidil specifically stimulated PKAII but only did so in the presence of small amounts of added cAMP. Furthermore, the PKA-dependent 16Ser phosphorylation of PLB was markedly reduced in I/R. Trapidil largely normalized the 16Ser phosphorylation of PLB. CONCLUSIONS: The data demonstrate cardioprotective actions of trapidil in I/R and show a PKAII-dependent cAMP sensitizing effect of the compound. They also indicate PKA-dependent PLB phosphorylation as a target, suggesting an improved Ca(2+) uptake by the sarcoplasmic reticulum. This action might be involved in the cardioprotective effects of trapidil.