bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Characterization of a Spheroidal Coculture Model of Endothelial Cells and Fibroblasts for Improving Angiogenesis in Tissue Engineering
Authors: Wenger Andreas , Kowalewski Nadja , Stahl Andreas , Mehlhorn Alexander T. , Schmal Hagen , Stark G. Björn , Finkenzeller Günter
Published: March 2006

Neovascularization is a critical step in tissue engineering applications since implantation of voluminous grafts without sufficient vascularity results in hypoxic cell death of central tissues. We have developed a three-dimensional spheroidal coculture system consisting of human umbilical vein endothelial cells (HUVECs) and human primary fibroblasts (hFBs) to improve angiogenesis in tissue engineering applications. Morphological analysis of cryosections from HUVEC/hFB cospheroids revealed a characteristic temporal and spatial organization with HUVECs located in the center of the cospheroid and a peripheral localization of fibroblasts. In coculture spheroids, the level of apoptosis of endothelial cells was strongly decreased upon cocultivation with fibroblasts. Collagen-embedded HUVEC spheroids develop numerous lumenized capillary-like sprouts. This was also apparent for HUVEC/hFB cospheroids, albeit to a lesser extent. Quantification of cumulative sprout length revealed an approximately 35% reduction in endothelial cell sprouting upon cocultivation with fibroblasts in cospheroids. The slight reduction in endothelial cell sprouting was not mediated by a paracrine mechanism but is most likely due to the formation of heterogenic cell contacts between HUVECs and hFBs within the cospheroid. The model system introduced in this study is suitable for the development of a preformed lumenized capillary-like network ex vivo and may therefore be useful for improving angiogenesis in in vivo tissue engineering applications.
Mitotic Polyploidization in Trophoblast Giant Cells of the Alpaca
Authors: Klisch K. , Bevilacqua E. , Olivera L.V.M.
Published: March 2006

Genome multiplication is a typical feature of trophoblast giant cell (TGC) development in many species. Elevated nuclear DNA contents can be achieved by modified cell cycles with a complete lack of mitosis (endoreduplication) or with incomplete mitoses. The aim of this study is to characterize genome multiplication in the alpaca TGC. Placental tissues of gestation days 150, 264 and 347 (near term) and term placentae were processed for light microscopy and for transmission electron microscopy. Each TGC showed many nuclear profiles. Observation of serial sections revealed that TGCs are truly multinucleate with several highly lobulated nuclei. Feulgen staining showed that TGC nuclei have a higher DNA content than nuclei of other trophoblast cells. The number of argyrophilic nucleolar organizer regions (AgNORs) in nuclear profiles of TGC was between 15 and 100, while other trophoblast cells showed 1 or 2 AgNORs. Large multipolar mitotic figures with maximal diameters of 80 µm were observed in the alpaca placentas on gestation days 264 and 347. No cytokinesis was seen in TGC. The results show that the mode of genome multiplication in the alpaca TGC is mitotic polyploidization. Subsequent acytokinetic mitoses may lead to an accumulation of chromosomes and centrioles in TGC. With increasing ploidy levels, the shape of these polyploidizing mitoses becomes more irregular. The restitution of nuclei after these complex multipolar mitoses is likely to result in the irregular nuclear shape in TGC.
The Zebrafish (Danio rerio): A Model System for Cranial Suture Patterning
Authors: Quarto Natalina , Longaker Michael T.
Published: March 2006

The zebrafish (Danio rerio) is an alluring model system currently used to study early embryonic development, organogenesis and gene functional analysis. However, few studies have been devoted to post-embryonic development. We have explored the possibility of using this organism to analyze how cranial suture patterning occurs. This study reports on the establishment of the zebrafish skull vault anatomy, calvarial osteogenesis, and cranial suture morphology. Our results demonstrate that the anatomy of the zebrafish cranial vault and cranial sutures is very similar to that of mammalian organisms. Indeed, the zebrafish represents a versatile and valuable model system for the study of the biogenesis of cranial sutures.
Corrosion Chemistry of Copper: Formation of Potentially Skin-Diffusible Compounds
Authors: Hostýnek Jurij J.
Published: March 2006

Copper and its alloys are subject to chemical reactions on exposure to environmental or physiological factors, whereby products are potentially generated which become diffusible through mammalian skin. The chemistry of oxidation is reviewed as well as the factors contributing to corrosion. Skin exudates (sweat and sebum) can react with metal surfaces they come in contact with, but even in the healthy organism their composition is variable, as a function of physical, pharmacological and environmental conditions, gender, age, sweat rate or body site. This overview addresses sweat and sebum composition, and discusses components which determine the skin’s corrosive action: chloride ion, low-molecular-weight acids and amino acids in sweat, and fatty acids in sebum, which hold the potential to solubilize copper-containing metal objects. These components can form copper salts and soaps whose molecular characteristics (size and polarity) will determine the rate and route of cutaneous penetration.
Influence of Dementia on Antithrombotic Therapy Prescribed before Stroke in Patients with Atrial Fibrillation
Authors: Lefebvre Catherine , Deplanque Dominique , Hénon Hilde , Touzé Emmanuel , Parnetti Lucilla , Pasquier Florence , Gallai Virgilio , Leys Didier
Published: March 2006

Background and purpose: Oral anticoagulation (OAC) decreases the risk of stroke in patients with nonvalvular atrial fibrillation (NVAF), but remains underused in practice. The aim of this study was to test the hypothesis that prestroke dementia influenced the nonprescription of OAC before stroke. Methods: This is an ancillary study of Stroke in Atrial Fibrillation Ensemble II, an observational study conducted in patients with a previously known NVAF, consecutively admitted for an acute stroke to French and Italian centers. Prestroke dementia was evaluated by the clinical physician and validated by an Informant Questionnaire for Cognitive Decline in the Elderly score of ≧104 in patients with a reliable informant. Results: Of 204 patients, 24 patients met criteria for prestroke dementia according to GP’s opinion. The only variables independently associated with OAC before stroke were follow-up by a cardiologist (adjusted OR: 3.33; 95% CI: 1.47–7.53) and a younger age of patients (adjusted OR: 0.94; 95% CI: 0.89–0.99). Variables independently associated with any antithrombotic drug therapy before stroke were follow-up by a general practitioner (adjusted OR: 2.78; 95% CI: 1.09–7.11), and by a cardiologist (adjusted OR: 3.15; 95% CI: 1.48–6.69). Conclusion: In daily practice, the under-prescription of OAC in patients with NVAF mainly depends on co-morbidity and on characteristics of the physician, not on prestroke dementia.
The Inverse Association of Elevated Serum Bilirubin Levels with Subclinical Carotid Atherosclerosis
Authors: Vítek Libor , Novotný Ladislav , Šperl Michal , Holaj Robert , Spáčil Jiří
Published: March 2006

Background: Serum bilirubin is negatively associated with the development of coronary heart disease. In the present study, we have focused on the analysis of intima-media thickness (IMT) of the common carotid artery in hyper- and normobilirubinemic subjects. Methods: The study was performed on 111 men without manifested atherosclerosis. In all subjects, complete biochemical tests were determined along with the examination of IMT by carotid ultrasound. Results: The mean IMT in hyperbilirubinemic subjects as compared with controls was substantially lower (p = 0.017), and hyperbilirubinemic men also had very low age-adjusted prevalence odds ratios for having IMT above the 50th percentiles of controls, even after adjustment for selected vascular risk factors (p = 0.034). Conclusions: In the present study, we demonstrate the inverse relationship between serum bilirubin and IMT in healthy men.
Relaxant Effects of the Soluble Guanylate Cyclase Activator and NO Sensitizer YC-1 in Piglet Pulmonary Arteries
Authors: González-Luis Gema , Cogolludo Angel , Moreno Laura , Lodi Federica , Tamargo Juan , Pérez-Vizcaíno Francisco , Villamor Eduardo
Published: March 2006

Background: The indazole derivative YC-1 has been characterized as a nitric oxide (NO)-independent and heme dependent soluble guanylate cyclase (sGC) activator, which also sensitizes sGC to NO. Objective: To examine the effects of YC-1 on vascular relaxation in newborn and 2-week-old piglet pulmonary arteries. The effect of YC-1 on the relaxation induced by exogenous NO was also analyzed. Methods: Isolated rings from third branch pulmonary arteries and fifth–seventh-generation intrapulmonary arterioles were mounted in organ chambers for isometric tension recording. Arteries were precontracted with the thromboxane A2 mimetic U46619. Results: YC-1 induced relaxation was greater in 2-week-old pulmonary arteries and was abolished by the sGC inhibitor ODQ (10 µM). YC-1 induced relaxation was similar in conduit pulmonary arteries and arterioles. In the 2-week-old conduit pulmonary arteries, the response to YC-1 was significantly reduced when the endothelium was removed or after incubation with the NO synthase inhibitor L-NAME (0.1 mM). YC-1 augmented NO-induced relaxation in 2-week-old but not in neonatal conduit pulmonary arteries. Conclusions: Our results indicate that YC-1 induced pulmonary vascular relaxation in conduit and resistance pulmonary arteries and these effects increased with postnatal age. In the 2-week-old conduit pulmonary arteries and besides being a direct activator of sGC, YC-1 produced endothelium-dependent relaxation and synergized with exogenous NO.
Bronchoalveolar Lavage Fluid D Dimer Levels Are Higher and More Prevalent in Black Patients with Pulmonary Sarcoidosis
Authors: Perez Rafael L. , Kimani Anthony P. , King Jr. Talmadge E. , Aguayo Samuel M. , Roman Jesse
Published: March 2006

Background: Abnormalities of lung coagulation and fibrinolysis in sarcoidosis are thought to play a role in the pathogenesis of this disease. Objective: We previously showed that bronchoalveolar lavage fluid (BALF) D dimer directly correlated with various measures of severity in sarcoidosis. Here, we analyze our observation that BALF D dimer was more frequently found at higher levels in African-American patients with pulmonary sarcoidosis. Methods: BALF D dimer was measured in 55 subjects with pulmonary sarcoidosis and 31 healthy volunteers by enzyme immunoassay. The healthy group established a normal range of BALF D dimer with 71 ng/ml as the highest measured level. This was the cut point for comparisons among the patients with sarcoidosis. Results: High BALF D dimer levels (>71 ng/ml) were found in younger patients with sarcoidosis and were associated with a significantly lower percent predicted forced expiratory volume in 1 s and greater numbers of BAL lymphocytes. Black patients with sarcoidosis had higher BALF D dimer levels (median 131, range 0–2,040 ng/ml) than white patients (median 18, range 0–605 ng/ml; p = 0.011). Higher than normal BALF D dimer levels were found in 61% of the black subjects with sarcoidosis, but in only 20% of the white individuals (χ2 = 5.539, p = 0.019). BALF D dimer was the only disease measure that discriminated black from white individuals with sarcoidosis. Conclusion: BALF D dimer is an indicator of lung fibrin formation and degradation in sarcoidosis. The relationship of high D dimer levels with greater BAL lymphocytosis and worse lung function may be a marker of active sarcoidosis, especially in African-Americans who tend to suffer a more serious form of the disease.
Isolation and Characterization of Vasohibin-2 as a Homologue of VEGF-Inducible Endothelium-Derived Angiogenesis Inhibitor Vasohibin
Authors: Shibuya Takumi , Watanabe Kazuhide , Yamashita Hiroshi , Shimizu Kazue , Miyashita Hiroki , Abe Mayumi , Moriya Takuya , Ohta Hideki , Sonoda Hikaru , Shimosegawa Tooru , Tabayashi Koichi , Sato Yasufumi
Published: March 2006

Objective—

We recently isolated vasohibin, a novel vascular endothelial growth factor (VEGF)-inducible endothelium-derived angiogenesis inhibitor. Our aim is to find DNA sequences homologous to vasohibin and determine their expression profile.

Methods and Results—

By the search of DNA sequences in the database, we found one homologous gene and designated it vasohibin-2. Overall amino acid sequence homology between the prototype vasohibin (vasohibin-1) and vasohibin-2 was >50%. Vasohibin-2 exhibited antiangiogenic activity. Vasohibin-2 expression in cultured endothelial cells was low and not inducible by the stimulation that induced vasohibin-1. However, the immunohistochemical analysis revealed that vasohibin-1 and -2 were diffusely expressed in endothelial cells in embryonic organs during mid-gestation. After that time point, vasohibin-1 and -2 became faint, but persisted to a certain extent in arterial endothelial cells from late gestation to neonate. Expression of vasohibin-1 and -2 could be augmented in vivo by local transfection with the VEGF gene in the embryonic brain or by cutaneous wounding in adult mice.

Conclusion—

These results suggest that vasohibin-2, in combination with vasohibin-1, forms a novel family of angiogenesis inhibitors.
Effect of Ezetimibe on the In Vivo Kinetics of ApoB-48 and ApoB-100 in Men With Primary Hypercholesterolemia
Authors: Tremblay André J. , Lamarche Benoît , Cohn Jeffrey S. , Hogue Jean-Charles , Couture Patrick
Published: March 2006

Objective—To examine the impact of ezetimibe, a selective inhibitor of intestinal cholesterol absorption, on the in vivo kinetics of apolipoproteins (apo) B-48 and B-100 in humans.

Methods and Results—Kinetics of triglyceride-rich lipoprotein (TRL) apoB-48 and very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) apoB-100 labeled with a stable isotope were assessed at baseline and at the end of 8 weeks of treatment with 10 mg/d of ezetimibe in 8 men with moderate primary hypercholesterolemia. Data were fit to a multicompartmental model using SAAMII to calculate fractional catabolic rate (FCR) and production rate (PR). Ezetimibe significantly decreased total and LDL cholesterol concentrations by −14.5% and −22.0% (P=0.004), respectively, with no significant change in plasma triglyceride and high-density lipoprotein (HDL) cholesterol levels. Ezetimibe had no significant effect on TRL apoB-48 kinetics and pool size (PS). However, VLDL and IDL apoB-100 FCRs were significantly increased (+31.2%,P=0.02 and +20.8%,P=0.04, respectively) with a concomitant elevation of VLDL apoB-100 PR (+20.9%,P=0.04). Furthermore, LDL apoB-100 PS was significantly reduced by −23.2% (P=0.004), caused by a significant increase in FCR of this lipoprotein fraction (+24.0%,P=0.04).

Conclusions—These results indicate that reduction of plasma LDL cholesterol concentration after treatment with ezetimibe is associated with an increase in FCR of apoB-100–containing lipoproteins.
Shear Stress Regulates Forward and Reverse Planar Cell Polarity of Vascular Endothelium In Vivo and In Vitro
Authors: McCue Shannon , Dajnowiec Dorota , Xu Feng , Zhang Ming , Jackson Moira R. , Langille B. Lowell
Published: March 2006

Cultured vascular endothelium displays profound morphological adaptations to shear stress that include planar cell polarity (PCP) that is directed downstream. Endothelial cells in blood vessels are also polarized; however, the direction of polarity is vessel specific, and shear-independent mechanisms have been inferred. The regulation of endothelial PCP is therefore controversial. We report that the direction of PCP in blood vessels is age and vessel specific; nonetheless, it is caused by shear-related regulation of glycogen synthase kinase-3β (GSK-3β), a profound regulator of endothelial microtubule stability. When GSK-3β is inhibited, PCP reverses direction. Endothelium is the only cell type studied to date that can reverse direction of polarity. Tight regulation of GSK-3β, microtubule dynamics, and cell polarity was also required for the striking morphological responses of endothelium to shear stress (cell elongation and orientation with shear). Finally, the cytoskeletal polarity displayed in blood vessels is associated with polarized (shear-directed) cell mitoses that have important effects on endothelial repair. Vascular endothelium therefore displays a novel mode of mechanosensitive PCP that represents the first example of a single cell type that can reverse direction of polarity.
Novel Role for STAT-5B in the Regulation of Hsp27–FGF-2 Axis Facilitating Thrombin-Induced Vascular Smooth Muscle Cell Growth and Motility
Authors: Cao Huiqing , Dronadula Nagadhara , Rizvi Farhan , Li Quanyi , Srivastava Kalyan , Gerthoffer William T. , Rao Gadiparthi N.
Published: March 2006

Previously, we have demonstrated that STAT-3 plays a role in thrombin-induced VSMC motility. To learn more about the role of STATs in the mitogenic and chemotactic signaling events of thrombin, here we have studied the role of STAT-5. Thrombin activated STAT-5 as measured by its tyrosine phosphorylation, DNA binding, and reporter gene activity. Inhibition of STAT-5B, but not STAT-5A, by adenovirus-mediated expression of its respective dominant-negative mutants suppressed thrombin-induced VSMC growth and motility. Thrombin induced the expression of Hsp27 and FGF-2 in a time- and STAT-5B-dependent manner in VSMC. In addition, small interfering RNA-directed depletion of Hsp27 levels or adenovirus-mediated expression of its dominant-negative mutant attenuated thrombin-induced FGF-2 expression, growth, and motility of VSMC. An increased association of STAT-5B with STAT-3 occurred in response to thrombin and adenovirus-mediated expression of dnSTAT-3 suppressed thrombin-induced Hsp27 and FGF-2 induction, DNA synthesis and motility in VSMC. Together, these results indicate that thrombin-induced VSMC growth and motility require STAT-5B/STAT-3–dependent expression of Hsp27 and FGF-2. These observations also suggest that STAT-5B/STAT-3/Hsp27/FGF-2 signaling via its involvement in the regulation of VSMC growth and motility may play an important role in the pathogenesis of vascular diseases such as restenosis after angioplasty.
VEGF Family Members Regulate Myocardial Tubulogenesis and Coronary Artery Formation in the Embryo
Authors: Tomanek Robert J. , Ishii Yasuo , Holifield Jennifer S. , Sjogren Christina L. , Hansen Heidi K. , Mikawa Takashi
Published: March 2006

This study tested the hypothesis that coronary tubulogenesis and coronary artery formation require VEGF family members. Quail embryos were injected with soluble vascular endothelial growth factor (VEGF) receptors R1 (Flt-1), R2 (Flk-1), R3 (Flt-4), VEGF-Trap (a chimera of R1 and R2), or neutralizing antibodies to VEGF-A, VEGF-B, or fibroblast growth factor (FGF)-2. Our data document that tubulogenesis is temporally dependent on multiple VEGF family members, because the early stage of tubulogenesis was markedly inhibited by VEGF-Trap and to a lesser extent by soluble VEGFR-1. Some inhibition of tubulogenesis was documented when anti-FGF-2, but not anti-VEGF-A, antibodies were injected at embryonic day 6 (E6). Most importantly, we found that VEGF-Trap injected at either E6 or E7 prevented the formation of coronary arteries. Soluble VEGFR-1 and soluble VEGFR-2 modified the formation of coronary arteries, whereas soluble VEGFR-3 was without effect. Antibodies to VEGF-B, but not VEGF-A, had a strong inhibitory effect on coronary artery development. The absence of coronary artery stems, and thus a functional coronary circulation, in the embryos injected with VEGF-Trap caused an accumulation of erythrocytes in the subepicardium and muscular interventricular septum. Using retroviral cell tagging, we showed that some of the erythrocytes in blood islands and small vascular tubes were progeny of the proepicardium. Thus, another salient finding of this study is the first definitive documentation of proepicardially derived hemangioblasts, which can differentiate into erythrocytes.
Association Between Atherosclerotic Aortic Plaques and Left Ventricular Hypertrophy in Patients With Cerebrovascular Events
Authors: Hueb João Carlos , Zanati Silméia G. , Okoshi Katashi , Raffin César N. , de Arruda Silveira Liciana Vaz , Matsubara Beatriz B.
Published: March 2006

Background and Purpose—

The purpose of this research was to evaluate whether an association exists between the presence of atherosclerotic plaque in the thoracic aorta and left ventricular hypertrophy (LVH) in patients with a cerebrovascular event.

Methods—

We included 116 consecutive patients (79 men; mean age, 62±12.4 years) with previous history of stroke or transient ischemic attack in a cross-sectional study. Transthoracic echocardiogram was performed to diagnose LVH and transesophageal echocardiogram for the detection of atheromas of the thoracic aorta. Continuous variables were analyzed by Student
t
or Mann-Whitney tests and categorized variables by Goodman test. From the significant association of LVH and age with atheromatous disease of the aorta, an adjustment to the multivariate logistic model was made using high blood pressure history or age as covariates. All of the statistical tests were carried out at a level of 5% significance.

Results—

Almost half of the patients (43.1%) presented atherosclerotic lesions in the aorta. LVH was present in 90.0% of patients with plaque and in only 30.3% of patients without plaque. Using high blood pressure as a covariate, the risk of patients with LVH presenting atherosclerotic plaque in the aorta was 18.23-fold greater than the risk for patients without LVH (95% CI, 5.68 to 58.54;
P
<0.0001). Adding age into the model, the risk increased to 26.36 (95% CI, 7.14 to 97.30;
P
<0.0001).

Conclusions—

LVH detected by conventional echocardiogram is associated with high risk of atherosclerotic plaque in the aorta and would be used as a criterion for indication of transesophageal echocardiography in patients with previous stroke or transient ischemic attack LVH.
Translating the Results of Randomized Trials into Clinical Practice
Authors: Hylek Elaine M. , D’Antonio James , Evans-Molina Carmella , Shea Carol , Henault Lori E. , Regan Susan
Published: March 2006

Background and Purpose—

Numerous studies have documented under use of warfarin particularly among elderly patients. A better understanding of the discrepancy between trials and clinical practice will help inform stroke prevention strategies in this vulnerable age group. The study objective was to prospectively assess the use of antithrombotic therapy among a contemporary cohort of patients with atrial fibrillation at the time of hospital discharge. In addition to baseline characteristics, we sought to define the physician-cited reason for not prescribing warfarin for each patient.

Methods—

Patients with atrial fibrillation were prospectively identified and followed to hospital discharge. Enrolled patients were ≥65 years of age, not taking warfarin on admission, and had their longitudinal care provided at our institution. Predictors of warfarin use were determined and physician-cited contraindications were compared across age groups.

Results—

Fifty-one percent (n=206) of patients were discharged on warfarin: 75% of those 65 to 69 years of age, 59% 70 to 79, 45% 80 to 89, and 24% age ≥90 years. Of the remaining 199 patients, 83% had ≥2 major risk factors for stroke, and 98% were felt to have contraindications including nearly 25% who were unable to tolerate warfarin in the past. Among patients age ≥80, falling was the most often physician-cited reason for not prescribing warfarin (41%) followed by hemorrhage (28%).

Conclusion—

Our findings suggest that many elderly patients at high risk for stroke may not be optimal candidates for anticoagulant therapy. There is a pressing need for alternative stroke prevention strategies for this expanding patient population.
Multimodal Reperfusion Therapy for Acute Ischemic Stroke
Authors: Gupta Rishi , Vora Nirav A. , Horowitz Michael B. , Tayal Ashis H. , Hammer Maxim D. , Uchino Ken , Levy Elad I. , Wechsler Lawrence R. , Jovin Tudor G.
Published: March 2006

Background and Purpose—

Endovascular therapies using mechanical and pharmacological modalities for large vessel occlusions in acute stroke are rapidly evolving. Our aim was to determine whether one modality is associated with higher recanalization rates.

Methods—

We retrospectively reviewed 168 consecutive patients treated with intra-arterial (IA) therapy for acute ischemic stroke between May 1999 and November 15, 2005. Demographic, clinical, radiographic, angiographic, and procedural notes were reviewed. Recanalization was defined as achieving thrombolysis in myocardial infarction 2 or 3 flow after intervention. A logistic regression model was constructed to determine independent predictors of successful recanalization.

Results—

A total of 168 patients were reviewed with a mean age of 64±13 years and mean National Institutes of Health Stroke Scale score of 17±4. Recanalization was achieved in 106 (63%) patients. Independent predictors of recanalization include: the combination of IA thrombolytics and glycoprotein IIb/IIIa inhibitors (odds ratio [OR], 2.9 [95% CI, 1.04 to 6.7];
P
<0.048), intracranial stent placement with angioplasty (OR, 4.8 [95% CI, 1.8 to 10.0];
P
<0.001), or extracranial stent placement with angioplasty (OR, 4.2 [95% CI, 1.4 to 9.8];
P
<0.014). Lesions at the terminus of the internal carotid artery were recalcitrant to revascularization (OR, 0.34 [95% CI, 0.16 to 0.73];
P
value 0.006).

Conclusions—

Intracranial or extracranial stenting or combination therapy with IA thrombolytics and glycoprotein IIb/IIIa inhibitors in the setting of multimodal therapy is associated with successful recanalization in patients treated with multimodal endovascular reperfusion therapy for acute ischemic stroke.
Toward a Multimodal Neuroprotective Treatment of Stroke
Authors: Fisher Marc , Dávalos Antoni , Rogalewski Andreas , Schneider Armin , Ringelstein E. Bernd , Schäbitz Wolf-Rüdiger
Published: March 2006

Background and Purpose—

Stroke remains a common medical problem with importance attributable to the demographic changes in industrialized societies.

Summary of Review—

After years of setbacks, acute stroke therapy has finally emerged, including thrombolysis with tissue plasminogen activator (t-PA). However, t-PA treatment is limited by a narrow time window and side effects, so that only 3% of all stroke patients receive thrombolysis. Unimodal targeting of key events in stroke pathophysiology was not effective in providing long-term benefits, leading to negative results in previous clinical neuroprotective stroke trials. A successful future stroke therapy should approach multiple pathophysiological mechanisms besides revascularization at once, including reduction of t-PA–related side effects, prevention of cell death, stimulation of neuroregeneration, and plasticity.

Conclusions—

Strategies targeting these processes include multiple combination therapies as well as treatment with multimodal drugs that interact with these mechanisms. Here, we review such combination approaches, and outline how this concept could be developed into future stroke treatment.
The Risks and Safety of Clopidogrel in Pediatric Arterial Ischemic Stroke
Authors: Soman Teesta , Rafay Mubeen F. , Hune Selina , Allen Anita , MacGregor Daune , deVeber Gabrielle
Published: March 2006

Background and Purpose—

The purpose of this study was to determine safety and tolerability of clopidogrel in children with arterial ischemic stroke (AIS). Clopidogrel is the alternative antiplatelet medication when aspirin is not tolerated or fails. The possible risks and safety of clopidogrel in children with AIS have not been assessed.

Methods—

This is a prospective consecutive cohort study of children with AIS who were started on clopidogrel. Seventeen children were included.

Results—

Two children developed subdural hematomas while on clopidogrel in conjunction with aspirin. Two others had headache or hand numbness. No other side effects like rash or gastrointestinal upsets were reported.

Conclusions—

We found clopidogrel to be relatively well tolerated in the pediatric population. In combination with aspirin and in the presence of other risk factors, intracranial bleeding may be seen.
The Relation of Stroke Admissions to Recent Weather, Airborne Allergens, Air Pollution, Seasons, Upper Respiratory Infections, and Asthma Incidence, September 11, 2001, and Day of the Week
Authors: Low Ronald B. , Bielory Leonard , Qureshi Adnan I. , Dunn Van , Stuhlmiller David F.E. , Dickey David A.
Published: March 2006

Background and Purpose—

Some previous research links stroke incidence to weather, some links strokes to air pollution, and some report seasonal effects. Alveolar inflammation was proposed as the mechanistic link. We present a unified model of time, weather, pollution, and upper respiratory infection (URI) incidence.

Methods—

We combined existing databases: US Environmental Protection Agency pollution levels, National Weather Service data, counts of airborne allergens, and New York City Health and Hospitals Corporation counts of stroke, asthma, and URI patients. We used autoregressive integrated moving average modeling (a statistical time series modeling technique) with stroke admissions as the response variable and day of week, holidays, September 11th, and other counts and levels as explanatory variables.

Results—

Using a broad definition of stroke, there were 5.1±2.3 stroke admissions per day: narrowly defined, 4.2±2.1 strokes per day. There are relatively fewer strokes on Sundays (0.50 strokes;
P
=0.0011), Saturdays (0.62;
P
<0.0001), Fridays (0.38;
P
=0.0009) and holidays (0.875;
P
=0.0016). We found relatively small, independent exacerbating effects of higher air temperature (
P
=0.0211), dry air (
P
=0.0187), URIs, (
P
<0.0001), grass pollen (
P
=0.0341), sulfur dioxide (SO
2
;
P
=0.0471), and suspended particles <10 μm in size (
P
=0.0404). These effects are modest: ≤0.6, 0.6, 2.4, 1, 0.9, and 0.7 strokes per day, respectively. We did not find statistically significant exacerbating effects of other variables.

Conclusions—

We found statistically significant, independent exacerbating effects of warmer, drier air, URIs, grass pollen, SO
2
, and particulate air pollution. The model supports the theory that links pulmonary inflammation to stroke.
Methodology and Results of Calculating Central California Surface Temperature Trends: Evidence of Human-Induced Climate Change?
Authors: Christy John R. , Norris William B. , Redmond Kelly , Gallo Kevin P.
Published: March 2006

A procedure is described to construct time series of regional surface temperatures and is then applied to interior central California stations to test the hypothesis that century-scale trend differences between irrigated and nonirrigated regions may be identified. The procedure requires documentation of every point in time at which a discontinuity in a station record may have occurred through (a) the examination of metadata forms (e.g., station moves) and (b) simple statistical tests. From this “homogeneous segments” of temperature records for each station are defined. Biases are determined for each segment relative to all others through a method employing mathematical graph theory. The debiased segments are then merged, forming a complete regional time series. Time series of daily maximum and minimum temperatures for stations in the irrigated San Joaquin Valley (Valley) and nearby nonirrigated Sierra Nevada (Sierra) were generated for 1910–2003. Results show that twentieth-century Valley minimum temperatures are warming at a highly significant rate in all seasons, being greatest in summer and fall (> +0.25°C decade−1). The Valley trend of annual mean temperatures is +0.07° ± 0.07°C decade−1. Sierra summer and fall minimum temperatures appear to be cooling, but at a less significant rate, while the trend of annual mean Sierra temperatures is an unremarkable −0.02° ± 0.10°C decade−1. A working hypothesis is that the relative positive trends in Valley minus Sierra minima (>0.4°C decade−1 for summer and fall) are related to the altered surface environment brought about by the growth of irrigated agriculture, essentially changing a high-albedo desert into a darker, moister, vegetated plain.
Can We Expect More Extreme Precipitation on the Monthly Time Scale?
Authors: Benestad Rasmus E.
Published: March 2006

The Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report states that instrumental records show an increase in precipitation by +0.5%–1% decade−1 in much of the Northern Hemisphere mid- and high latitudes and a decrease of −0.3% decade−1 over subtropical land areas. It has been postulated that these trends are associated with the enhanced levels of atmospheric CO2. In this context, it is natural to ask how continuing rising levels of CO2 may affect the climate in the future. The past IPCC reports have documented numerous studies where increased greenhouse gas concentrations have been prescribed in global climate model simulations. Now, new simulations with state-of-the-art climate models are becoming available for the next IPCC report [the Fourth Assessment Report (AR4)], and results from a number of these simulations are examined in order to determine whether they indicate a change in extreme precipitation on a monthly basis. The analysis involves a simple record–statistics framework and shows that the upper tails of the probability distribution functions for monthly precipitation are being stretched in the mid- and high latitudes where mean-level precipitation increases have already been reported in the past. In other words, values corresponding to extreme monthly precipitation in the past are, according to these results, becoming more frequent.
Nonstationarity of the Intraseasonal Oscillations Associated with the Western North Pacific Summer Monsoon
Authors: Guan Bin , Chan Johnny C. L.
Published: March 2006

The nonstationarity of the intraseasonal oscillations (ISOs) associated with the western North Pacific summer monsoon (WNPSM) is examined using a wavelet analysis of outgoing longwave radiation (OLR). Both the 10–20- and 30–60-day ISOs are found to display significant interannual modulations, and their relative strengths vary with time. The variation of OLR associated with a strong ISO, either 10–20- or 30–60-day, could be as large as 20 W m−2 in magnitude. Case studies showed that the mechanism for development of low OLR may differ in individual years, and that the 10–20-day ISO, the 30–60-day ISO, and the seasonal cycle may each become dominant in different years.
New Spectroradiometers Complying with the NDSC Standards
Authors: Wuttke Sigrid , Seckmeyer Gunther , Bernhard Germar , Ehramjian James , McKenzie Richard , Johnston Paul , O'Neill Michael
Published: March 2006

The investigation of the effect of solar ultraviolet (UV) and visible radiation on biological organisms and photochemical reactions requires spectral measurements of the desired radiation parameters of high accuracy. The Network for the Detection of Stratospheric Change (NDSC) and the World Meteorological Organization have set up stringent requirements for high-quality spectral measurements of ultraviolet radiation. It is shown that two new instruments comply with these standards. One is the newly developed spectroradiometer of the Institute of Meteorology and Climatology, University of Hannover, Hannover, Germany. It is capable of covering the spectral range from the UV to the near-infrared (290–1050 nm) in a comparably fine resolution. One major aim is to deploy this instrument as a traveling NDSC spectroradiometer. The other new instrument is built for the U.S. National Science Foundation's UV Monitoring Network. It is designed to monitor UV and visible irradiance at high latitudes and covers a wavelength range from 280 to 600 nm. Data of both instruments show deviations of less than 5% for a wide range of atmospheric conditions compared to a NDSC spectroradiometer owned by the Climate Monitoring and Diagnostics Laboratory during the fifth North American Interagency Intercomparison for UV Spectroradiometers. Such deviations represent state-of-the-art instrumentation for conducting long-term measurements of solar UV radiation capable of detecting trends and supporting long-term measurements by traveling standards. Furthermore, there is now an instrument capable of measuring solar irradiance in a wavelength range from 250 to 1050 nm.
Ocean Wave Directional Spectra Estimation from an HF Ocean Radar with a Single Antenna Array: Methodology
Authors: Hisaki Yukiharu
Published: March 2006

A method to estimate ocean wave directional spectra using a high-frequency (HF) ocean radar was developed. The governing equations of wave spectra are integral equations of first- and second-order radar cross sections, the wave energy balance equation, and the continuity equation of surface winds. The parameterization of the source function is the same as that in WAM. Furthermore, the method uses the constraints that wave spectral values are smooth in both wave frequency and direction and that the propagation terms are small. The unknowns to be estimated are surface wind vectors at radial grids whose centers are the radar position, and wave spectral values at radial and wave frequency–direction grids. The governing equations are discretized in the radial and wave frequency–direction grids and are converted into a nonlinear minimization problem. Identical twin experiments showed that the present method can estimate wave spectra and dynamically extrapolate wave spectra, even in an inhomogeneous wave field.
Raman Lidar Measurements during the International H2O Project. Part I: Instrumentation and Analysis Techniques
Authors: Whiteman D. N. , Demoz B. , Rush K. , Schwemmer G. , Gentry B. , Di Girolamo P. , Comer J. , Veselovskii I. , Evans K. , Melfi S. H. , Wang Z. , Cadirola M. , Mielke B. , Venable D. , Van Hove T.
Published: March 2006

The NASA Goddard Space Flight Center (GSFC) Scanning Raman Lidar (SRL) participated in the International H2O Project (IHOP), which occurred in May and June 2002 in the midwestern part of the United States. The SRL received extensive optical modifications prior to and during the IHOP campaign that added new measurement capabilities and enabled unprecedented daytime water vapor measurements by a Raman lidar system. Improvements were also realized in nighttime upper-tropospheric water vapor measurements. The other new measurements that were added to the SRL for the IHOP deployment included rotational Raman temperature, depolarization, cloud liquid water, and cirrus cloud ice water content. In this first of two parts, the details of the operational configuration of the SRL during IHOP are provided along with a description of the analysis and calibration procedures for water vapor mixing ratio, aerosol depolarization, and cirrus cloud extinction-to-backscatter ratio. For the first time, a Raman water vapor lidar calibration is performed, taking full account of the temperature sensitivity of water vapor and nitrogen Raman scattering. Part II presents case studies that permit the daytime and nighttime error statistics to be quantified.
Resolution Enhancement Technique Using Range Oversampling
Authors: Yu Tian-You , Zhang Guifu , Chalamalasetti Anil B. , Doviak Richard J. , Zrníc Dusan
Published: March 2006

A novel resolution enhancement technique using range oversampling (RETRO) is presented. Oversampled signals are radar returns from shifted and overlapped resolution volumes in range. It has been recently shown that these signals can be whitened and averaged to optimally reduce the statistical error of weather spectral moment estimations for the case of uniform reflectivity and velocity. Using the same oversampled data, when the resolution is of interest, RETRO can reveal the variation of reflectivity and velocity in range at finescale. The idea is to utilize the redundant information contained in oversampled signals, which come from common regions, to improve the resolution defined by the range weighting function. As a result, oversampled data are optimally combined to produce high-resolution signals for spectral moment estimations. RETRO is demonstrated and verified using numerical simulations for two cases. In the first case, range variation of a tornadic vortex with a diameter of 120 m can be reconstructed by RETRO at a scale of 25 m when a 250-m pulse and an oversampling factor of 10 are used. Application of RETRO to mitigate ground clutter contamination is demonstrated in the second case.
Determining Bottom Reflectance and Water Optical Properties Using Unmanned Underwater Vehicles under Clear or Cloudy Skies
Authors: English David C. , Carder Kendall L.
Published: March 2006

An unmanned underwater vehicle (UUV) with hyperspectral optical sensors that measure downwelling irradiance and upwelling radiance was deployed over sandy bottoms, sea grass patches, and coral reefs near Lee Stocking Island, Bahamas, during the Coastal Benthic Optical Properties (CoBOP) program of 2000. These deployments occurred during both sunny and cloudy weather. If the rate of irradiance change due to cloud cover is slight, then the inclusion of a variable cloudy-irradiance factor will allow a reasonable estimation of water column absorption. Examination of data from a deployment in May 2000 under cloudy skies shows that the combination of hyperspectral light-field measurements, knowledge of the UUV's position in the water column, and a cloudy-irradiance factor permits consistent estimations of bottom reflectivity to be made from UUV measured reflectances. The spatial distribution of reflectance estimates obtained from a UUV may be useful for validation of airborne ocean color imagery.
Sea Surface Temperature Patterns on the West Florida Shelf Using Growing Hierarchical Self-Organizing Maps
Authors: Liu Yonggang , Weisberg Robert H. , He Ruoying
Published: March 2006

Neural network analyses based on the self-organizing map (SOM) and the growing hierarchical self-organizing map (GHSOM) are used to examine patterns of the sea surface temperature (SST) variability on the West Florida Shelf from time series of daily SST maps from 1998 to 2002. Four characteristic SST patterns are extracted in the first-layer GHSOM array: winter and summer season patterns, and two transitional patterns. Three of them are further expanded in the second layer, yielding more detailed structures in these seasons. The winter pattern is one of low SST, with isotherms aligned approximately along isobaths. The summer pattern is one of high SST distributed in a horizontally uniform manner. The spring transition includes a midshelf cold tongue. Similar analyses performed on SST anomaly data provide further details of these seasonally varying patterns. It is demonstrated that the GHSOM analysis is more effective in extracting the inherent SST patterns than the widely used EOF method. The underlying patterns in a dataset can be visualized in the SOM array in the same form as the original data, while they can only be expressed in anomaly form in the EOF analysis. Some important features, such as asymmetric SST anomaly patterns of winter/summer and cold/warm tongues, can be revealed by the SOM array but cannot be identified in the lowest mode EOF patterns. Also, unlike the EOF or SOM techniques, the hierarchical structure in the input data can be extracted by the GHSOM analysis.
Language and Understanding(1970)
Authors: Gadamer Hans-Georg
Published: March 2006

Understanding is a ‘language event’ founded upon a ‘silent agreement’ between participants in a conversation. This silent agreement, built up of conversational aspects held in common, is what makes social solidarity possible and shows that the methods of science are an inappropriate starting point for our self-understanding. However, with the advent of industrial technical civilization, the question arises whether understanding has come under the control of a centrally steered communication system where language is a consciously wielded instrument of politics with a corresponding loss of free insight and critical judgement. Only via a hermeneutic logic of words, which begins from recognition that words get their meaning from the open space of living conversation, can critical judgement be defended in the face of the authority of science and technology.
Classical and Philosophical Hermeneutics
Authors: Gadamer Hans-Georg
Published: March 2006

Hermeneutics is a mantic art involved in the translation of the unintelligible into the intelligible. However, within modern contexts the term possesses a more methodological sense - ‘a universal doctrine for the interpretation of signs’. This conception of hermeneutics was given impetus during the Renaissance with the quest for theological objectivity, but it was with Schleiermacher and other philosophers of the Romantic movement that hermeneutics was viewed as a universal ‘dialogical’ condition. The Romantic conception of hermeneutics was psychologized by Dilthey and re-founded upon the principle of consciousness. With Heidegger became conceived as an ontological phenomenon identical to Existenz itself. For Gadamer, hermeneutics criticizes the ‘pale abstractions’ of Enlightenment conceptions of philosophy for neglecting the work of concepts in philosophy; concepts that have their origins in the self-critical communicative movement of human interpretation.
The Temporality of Tarrying in Gadamer
Authors: Ross Sheila
Published: March 2006

This article presents Gadamer’s interest in temporality as his strategy for advancing hermeneutics as philosophy of experience, a strategy becoming significantly more salient with the appearance of his 1992 essay, ‘Wort und Bild’. I demonstrate how temporal categories readily demarcate the problem of ontological imbalance so central in Gadamer’s philosophical project, a demarcation that removes any illusion of compatibility between Gadamer and the hermeneutics of Paul Ricoeur. The article also considers some common misunderstandings of Gadamer resulting from a failure to take full account of his interest in temporality, misunderstandings that prohibit recognizing the radical potential of Gadamer’s hermeneutical philosophy for our understanding of human finitude. A full account of this orientation must begin with a grasp of the exemplariness of art in his philosophy, and in this connection, the article raises the question of Gadamer’s late interest in the distinct exemplariness, not of lyric poetry, but of narrative art.
Keepin’ This Little Town Going
Authors: Petrzelka Peggy , Mannon Susan E.
Published: March 2006

Past studies have shown that women’s volunteer work benefits communities but that women themselves tend to minimize their efforts. Most of these studies, however, have been limited to women volunteering in suburban and urban contexts. Drawing on a study of women volunteers in rural Iowa, the authors find that women frame their volunteer experiences in three ways: (1) as an expression of their maternal nature, (2) as a way to socialize, and (3) as a contribution to the local economy. The authors’ findings depart from past research in that the women in their sample do not downplay the importance of their volunteer work; rather, they recognize the importance of their unpaid labor for the social and economic vitality of the community. The authors argue this recognition stems from the particular context in which their volunteerism takes place, namely, in a devastated rural economy in which future economic potential rests on women’s hospitality work.