The selective α1 adrenoceptor antagonist HEAT reduces L‐DOPA‐induced dyskinesia in a rat model of Parkinson's disease

In Parkinson's disease (PD), the long term use of L‐DOPA results in major adverse effects including dyskinesia or abnormal involuntary movements. The present study focuses on the effect of the selective α₁ adrenoceptor antagonist HEAT (2‐[[β‐(‐4‐hydroxyphenyl)ethyl]aminomethyl]‐1‐tetralone) in the 6‐hydroxydopamine rat model of L‐DOPA‐induced dyskinesia. We demonstrate that the selective α₁ adrenoceptor antagonist HEAT (1 and 2 mg kg^?1), the α₂ adrenoceptor antagonist idazoxan (9 mg kg^?1), and the nonselective β₁/β₂ adrenoceptor antagonist propranolol (20 mg kg^?1) alleviate dyskinetic movements induced by L‐DOPA. Furthermore, the adrenoceptor antagonists at the doses used did not influence exploratory behavior in the open field system indicating that the antidyskinetic effect is not due to a reduction in general motor activity. Intrastriatal administration of the selective α₁ adrenoceptor agonist cirazoline via reverse in vivo microdialysis did not induce dyskinesia. Additionally, we measured plasma, brain, and CSF levels of HEAT. HEAT is a CNS active compound with a brain/plasma and CSF/plasma ratio of 4.29 and 0.15, respectively, which is appropriate for the investigation of α₁‐mediated mechanisms in CNS disorders. In conclusion, these results demonstrated for the first time that a α₁ adrenoceptor antagonist reduced L‐DOPA‐induced dyskinesia in a rat model. Further studies assessing the risk benefit in comparison to existing therapies are needed before considering α₁ adrenoceptor antagonists as a target for the development of new antidyskinetic compounds. Synapse 64:117–126, 2010. © 2009 Wiley‐Liss, Inc.     

Blood pressure reduction does not reduce perihematoma oxygenation: a CT perfusion study

Blood pressure (BP) reduction after intracerebral hemorrhage (ICH) is controversial, because of concerns that this may cause critical reductions in perihematoma perfusion and thereby precipitate tissue damage. We tested the hypothesis that BP reduction reduces perihematoma tissue oxygenation.Acute ICH patients were randomized to a systolic BP target of <150 or <180 mm Hg. Patients underwent CT perfusion (CTP) imaging 2 hours after randomization. Maps of cerebral blood flow (CBF), maximum oxygen extraction fraction (OEF^max), and the resulting maximum cerebral metabolic rate of oxygen (CMRO₂^max) permitted by local hemodynamics, were calculated from raw CTP data.Sixty-five patients (median (interquartile range) age 70 (20)) were imaged at a median (interquartile range) time from onset to CTP of 9.8 (13.6) hours. Mean OEF^max was elevated in the perihematoma region (0.44±0.12) relative to contralateral tissue (0.36±0.11; P<0.001). Perihematoma CMRO₂^max (3.40±1.67 mL/100 g per minute) was slightly lower relative to contralateral tissue (3.63±1.66 mL/100 g per minute; P=0.025). Despite a significant difference in systolic BP between the aggressive (140.5±18.7 mm Hg) and conservative (163.0±10.6 mm Hg; P<0.001) treatment groups, perihematoma CBF was unaffected (37.2±11.9 versus 35.8±9.6 mL/100 g per minute; P=0.307). Similarly, aggressive BP treatment did not affect perihematoma OEF^max (0.43±0.12 versus 0.45±0.11; P=0.232) or CMRO₂^max (3.16±1.66 versus 3.68±1.85 mL/100 g per minute; P=0.857). Blood pressure reduction does not affect perihematoma oxygen delivery. These data support the safety of early aggressive BP treatment in ICH.     

Prior antiplatelet use and infarct volume in ischemic stroke

BACKGROUND: Conflicting data exist on the role of antiplatelet agents in reducing incident ischemic stroke magnitude, but most prior studies used clinically-assessed neurologic deficit as the index of stroke extent rather than more precise volumetric measurements of infarct size. We assessed the relation of premorbid antiplatelet use to initial diffusion-weighted MRI (DWI) lesion volumes among acute ischemic stroke patients. METHODS: Consecutive patients presenting within 24 h of ischemic stroke over an 18-month period were studied. DWI lesions were outlined using a semi-automated threshold technique. Subjects were categorized into two groups: antiplatelet (AP) or no antithrombotic (NA). The relationship between prestroke antithrombotic status and DWI infarct volumes was examined using multivariate quantile regression. RESULTS: One hundred sixty-six individuals met study criteria: 75 AP and 91 NA patients. Median DWI volume was lower in the AP group than in the NA group (1.5 cc vs. 5.4 cc, p=0.031). A multivariable model (adjusting for age, history of transient ischemic attack, admission temperature, admission blood pressure, admission serum glucose, stroke onset to imaging interval, stroke mechanism, premorbid statin and antihypertensive use) demonstrated smaller infarcts in the AP vs. NA group (adjusted volume difference: -1.3 cc, 95% CI=-0.09, -2.5, p=0.037). Prior statin use, no history of TIA, large vessel atherosclerosis and microvascular ischemic disease stroke mechanism were also independently associated with reduced infarct volume. CONCLUSIONS: Prior antiplatelet treatment is independently associated with reduced cerebral infarct volume among acute ischemic stroke patients. Premorbid statin use, TIA history and stroke mechanism also predict infarct volume in ischemic stroke.     

Stroke Mimics Transported by Emergency Medical Services to a Comprehensive Stroke Center: The Magnitude of the Problem

Background

Despite the use of validated prehospital stroke scales, stroke mimics are frequent among patients transported by Emergency Medical Services to the Emergency Department. We aimed to describe the frequency and characteristics of neurological and non-neurological mimics transported to a comprehensive stroke center for acute stroke evaluation.

Human Merkel cell polyomavirus infection II. MCV is a common human infection that can be detected by conformational capsid epitope immunoassays

Merkel cell polyomavirus (MCV) is a newly‐discovered human tumor virus found in ～80% of Merkel cell carcinoma (MCC). The rate of MCV infection among persons without MCC is unknown. We developed a MCV virus‐like particle (VLP) enzyme‐linked immunoassay (EIA) that does not cross‐react with human BK or murine polyomaviruses. Peptide mapping of the MCV VP1 gene and immunoblotting with denatured MCV VLP are less sensitive than the MCV EIA in detecting MCV antibodies suggesting antibody reactivity in this assay primarily targets conformational but not linear epitopes. Among MCC patients, all 21 (100%) patients tested with MCV‐positive tumors had high serum MCV IgG but not high MCV IgM levels. Only 3 of 6 (50%) MCC patients with MCV‐negative tumors were positive for MCV antibodies. Sera from most adults, including 107 of 166 (64%) blood donors, 63 of 100 (63%) commercial donors and 37 of 50 (74%) systemic lupus erythematosus patients, show evidence for prior MCV exposure. Age‐specific MCV prevalence was determined by examining a cross‐sectional distribution of 150 Langerhans cell histiocytosis (an unrelated neoplasm) patient sera. MCV prevalence increases from 50% among children age 15 years or younger to 80% among persons older than 50 years. We did not find evidence for vertical transmission among infants. Although past exposure to MCV is common among all adult groups, MCC patients have a markedly elevated MCV IgG response compared with control patients. Our study demonstrates that MCV is a widespread but previously unrecognized human infection. © 2009 UICC     

Cannabinoids protect cells from oxidative cell death: a receptor-independent mechanism

Serum is required for the survival and growth of most animal cells. In serum-free medium, B lymphoblastoid cells and fibroblasts die after 2 days. We report that submicromolar concentrations of Delta(9)-tetrahydrocannabinol (THC), Delta(8)-THC, cannabinol, or cannabidiol, but not WIN 55,212-2, prevented serum-deprived cell death. Delta(9)-THC also synergized with platelet-derived growth factor in activating resting NIH 3T3 fibroblasts. The cannabinoids' growth supportive effect did not correlate with their ability to bind to known cannabinoid receptors and showed no stereoselectivity, suggesting a nonreceptor-mediated pathway. Direct measurement of oxidative stress revealed that cannabinoids prevented serum-deprived cell death by antioxidation. The antioxidative property of cannabinoids was confirmed by their ability to antagonize oxidative stress and consequent cell death induced by the retinoid anhydroretinol. Therefore, cannabinoids act as antioxidants to modulate cell survival and growth of B lymphocytes and fibroblasts.     

Colposcopy is superior to cytology for the detection of early genital human papillomavirus infection

Of 2232 women with no cytologic evidence of intraepithelial neoplasia, 250 (11.2%) were positive for human papillomavirus deoxyribonucleic acid (DNA) by filter in situ hybridization. In 150 of those human papillomavirus-positive patients, an adequate colposcopic examination of the cervix was possible; human papillomavirus infection was diagnosed in 104 women (70%). Cervical cytology showed evidence of human papillomavirus infection in only 23 patients (15%). The following colposcopic features were most common: acetowhite epithelium (29%), punctuation (18%), acetowhite spikes (17%), and mosaicism (9%). Colposcopy was essentially normal in 27%. In 64 hysterectomized patients, vaginal colposcopy showed evidence of human papillomavirus infection in 38 women (59%). Vaginal cytology showed signs of human papillomavirus infection in only 9% (N = 6). Acetowhite spikes were seen in 52%, acetowhite epithelium in 5%, punctuation in 3%, and normal findings in 40%. Histologic examination of 25 biopsy specimens (cervical, N = 15; vaginal, N = 10) showed mainly a lack of glycogenation, acanthosis, and elongation of rete pegs. Koilocytosis and dyskeratosis were seen only in a few cases as rare foci, hence the negative cytology. We conclude that colposcopy is far more sensitive than cytology for the detection of cervical and vaginal human papillomavirus infection.     

Single coronary artery originating from the right pulmonary artery

Summary An infant with a single coronary artery originating from the right pulmonary artery branch is the subject of this report. He survived to the age of one month possibly because of the association of two ventricular septal defects. While the pulmonary vascular resistance remained high, perfusion of the heart muscle was accomplished due to the pulmonary hypertension. The electrocardiogram did not show typical signs of infarction, but poor left ventricular contractility was observed by echocardiogram. The diagnosis was made postmortem. This specific coronary malformation has not been previously described and needs to be included in the classification of congenital coronary arteries anomalies.     

Increased adenine nucleotide translocator 1 in reactive astrocytes facilitates glutamate transport

A hallmark of central nervous system (CNS) pathology is reactive astrocyte production of the chronic glial scar that is inhibitory to neuronal regeneration. The reactive astrocyte response is complex; these cells also produce neurotrophic factors and are responsible for removal of extracellular glutamate, the excitatory neurotransmitter that rises to neurotoxic levels in injury and disease. To identify genes expressed by reactive astrocytes, we employed an in vivo model of the glial scar and differential display PCR and found an increase in the level of Ant1, a mitochondrial ATP/ADP exchanger that facilitates the flux of ATP out of the mitochondria. Ant1 expression in reactive astrocytes is regulated by transforming growth factor-beta1, a pluripotent CNS injury-induced cytokine. The significance of increased Ant1 is evident from the observation that glutamate uptake is significantly decreased in astrocytes from Ant1 null mutant mice while a specific Ant inhibitor reduces glutamate uptake in wild-type astrocytes. Thus, the astrocytic response to CNS injury includes an apparent increase in energy mobilization capacity by Ant1 that contributes to neuroprotective, energy-dependent glutamate uptake.