bluuebunny/crossref_metadata_2025 huggingface dataset:
Lead Interaction: Rare Cause of Oversensing During Implantation Procedure of Implantable Cardioverter‐Defibrillator System
Authors: GARDAS RAFAL , MLYNARSKI RAFAL , STASZAK KATARZYNA , DRZEWIECKA ANNA , PILAT EUGENIUSZ , ZAJAC TADEUSZ , KARGUL WLODZIMIERZ
Published: October 2006

A variety of etiologies can cause erroneous detection in patients with implantable cardioverter defibrillator (ICDs). Interaction between two endocardial leads is rare and uncommon in causing electrical noise. During a reimplantation procedure of an ICD system in a 68‐year‐old man, additional electrical signals could be detected. The interaction between two endocardial defibrillation leads was identified as the cause of sensing problems. When it is not possible to extract the nonfunctional endocardial lead during implantation of the new electrode, it should be implanted away and not in parallel from the old one to avoid interaction between them. A variety of etiologies can cause erroneous detection in patiens with ICD. Interaction between two endocardial leads is rare and uncommon to cause electrical noise.
‘Schools without walls?’ Developments and challenges in dental outreach teaching – report of a recent symposium
Authors: Eaton K. A. , De Vries J. , Widström E. , Gait T. C. , Bedi R. , Meyers I. , Feldman C. A. , Hobson R.
Published: October 2006

Abstract  During the 2004 annual meeting of the International Association for Dental Research, the Education Research Group held a symposium on dental outreach teaching. After a brief introduction, which reviews relevant aspects of the relatively sparse literature, this paper summarises the proceedings, the themes and conclusions that emerged and the research issues that were identified. It aims to describe aspects of current practice around the world and to promote future discussion. Presenters gave details of outreach programmes for dental undergraduates in Australia, Finland, Malaysia (and Southeast Asia), the United Kingdom and the United States. From these presentations four themes emerged. They were: reasons for the introduction of outreach teaching, its perceived beneficial effects, organisational issues, educational issues. The reasons included a recognition of the need to educate dental undergraduates as members of ‘care teams’ in the environments and communities where they were ultimately like to work and the current shortage of both suitable patients and teachers (faculty) in many dental schools. A wide range of potential benefits and some disadvantages were identified. The organisational issues were, in the main, seen to relate to finance and administration. The educational issues included the need to train and monitor the performance of teachers at outreach clinics and to assess the performance of the undergraduates whilst at the outreach locations. It was concluded that new technology made it easier to teach at a distance and it was possible to create a dental ‘school without walls’. It was recognised that few evaluations of dental outreach teaching have been carried out and that there were many research questions to be answered, including: whether it should be a voluntary or compulsory part of the undergraduate curriculum, how long it should last and what type of outcomes should be assessed.
The use of articulators in UK dental schools
Authors: Hindle J. R. , Craddock H. L.
Published: October 2006

Abstract  The increasing complexity of many restorative procedures often involves articulation of study and working casts to ensure accurate fabrication of restorations. Correct selection and use of articulators can be crucial to successful restoration. The aim of this paper is to determine which articulators are recommended for various restorative procedures in UK dental schools, for use by undergraduate students. A questionnaire‐based study of all UK dental schools was carried out, with a 100% response rate. Recommended articulator application for specified procedures was established from the literature and questionnaire results were compared with this. The results indicated that dental schools in the UK generally teach appropriate articulator use for most procedures. However, there are some limited areas of what may be argued to be inappropriate recommendation in some establishments.
INFLUENCE OF FOOD ENVIRONMENT ON LISTERIA MONOCYTOGENES INFECTION IN THE GUINEA PIG MODEL
Authors: PANG HOAN‐JEN E. , MATTHEWS KARL R.
Published: October 2006

Listeria monocytogenes is a widespread foodborne pathogen associated with severe illness in humans. Food composition, processing, storage, distribution and handling conditions are all factors that may individually or collectively contribute to the virulence of a pathogen. Using the guinea pig as a human surrogate, we investigated the impact of carrier vehicle and improper food handling practices on the infectivity of L. monocytogenes. Chocolate milk was artificially contaminated with L. monocytogenes prior to exposure to improper handling conditions. Improper handling of chocolate milk included leaving the milk at an elevated temperature (37C) and then placing it in a refrigerator (4C). Guinea pigs were orally challenged with either 102 or 108 cfu of L. monocytogenes in 1 mL of nutrient broth or chocolate milk that had been exposed to improper handling conditions. A third group was challenged with L. monocytogenes suspended in water. On days 2 and 4, upon enrichment of organ samples, the presence of L. monocytogenes was detected in 27% of the animals receiving the low dose regardless of the carrier vehicle and improper handling conditions. Animals fed the high dose (108 cfu) of L. monocytogenes had similar populations of the pathogen in the spleen and liver, regardless of the carrier vehicle. These results are significant in that a low dose (102 cfu) could lead to listerial infection. Under the conditions tested in this study, the carrier vehicle and exposure of the pathogen to improper handling practices had no detectable effect on the establishment of listerial infection in the guinea pig model.
The oestrogen receptor β contributes to sex related differences in endothelial function of murine small arteries via EDHF
Authors: Luksha Leonid , Poston Lucilla , Gustafsson Jan‐Åke , Hultenby Kjell , Kublickiene Karolina
Published: October 2006

Sex related differences in cardiovascular function have been reported in oestrogen receptor β knockout (ERβKO) mice. In this study we examined the role of endothelium‐derived hyperpolarizing factor (EDHF) in differences in small artery endothelial function between ERβKO and wild‐type (WT) mice. Small femoral arteries were isolated from ERβKO and WT mice and mounted on a wire myograph. Concentration–response curves to ACh were compared before and after incubation with inhibitors of nitric oxide (NO) and prostacyclin (PGI2) synthesis. Comparison of the expression of the principal vascular connexins (Cx37, 40 and 43), implicated in EDHF‐mediated dilatation were undertaken by immunohistochemistry. Vascular ultrastructure was studied by transmission and scanning electron microscopy. ACh‐induced relaxation of arteries (< 200 μm internal diameter) was greater in WT females versus males and was attributable to a greater EDHF component of relaxation. This sex difference was absent in ERβKO mice. Arteries from ERβKO males (but not females) were more sensitive to ACh compared to WT. The pharmacological evidence and morphological prerequisite for involvement of gap junctions in EDHF‐mediated responses was confirmed in male arteries. The absence of ERβ had no influence on expression of main Cx subtypes within vascular wall or on ultrastructure and morphology of the endothelium. The data suggest that in WT male mice, ERβ reduces EDHF‐mediated relaxation through gap junction communication.
RIG-I-Mediated Antiviral Responses to Single-Stranded RNA Bearing 5'-Phosphates
Authors: Pichlmair Andreas , Schulz Oliver , Tan Choon Ping , Näslund Tanja I. , Liljeström Peter , Weber Friedemann , Reis e Sousa Caetano
Published: October 2006

Double-stranded RNA (dsRNA) produced during viral replication is believed to be the critical trigger for activation of antiviral immunity mediated by the RNA helicase enzymes retinoic acid–inducible gene I (RIG-I) and melanoma differentiation–associated gene 5 (MDA5). We showed that influenza A virus infection does not generate dsRNA and that RIG-I is activated by viral genomic single-stranded RNA (ssRNA) bearing 5′-phosphates. This is blocked by the influenza protein nonstructured protein 1 (NS1), which is found in a complex with RIG-I in infected cells. These results identify RIG-I as a ssRNA sensor and potential target of viral immune evasion and suggest that its ability to sense 5'-phosphorylated RNA evolved in the innate immune system as a means of discriminating between self and nonself.
Dynamical Configuration of Binary Near-Earth Asteroid (66391) 1999 KW4
Authors: Scheeres D. J. , Fahnestock E. G. , Ostro S. J. , Margot J.-L. , Benner L. A. M. , Broschart S. B. , Bellerose J. , Giorgini J. D. , Nolan M. C. , Magri C. , Pravec P. , Scheirich P. , Rose R. , Jurgens R. F. , De Jong E. M. , Suzuki S.
Published: October 2006

Dynamical simulations of the coupled rotational and orbital dynamics of binary near-Earth asteroid 66391 (1999 KW4) suggest that it is excited as a result of perturbations from the Sun during perihelion passages. Excitation of the mutual orbit will stimulate complex fluctuations in the orbit and rotation of both components, inducing the attitude of the smaller component to have large variation within some orbits and to hardly vary within others. The primary's proximity to its rotational stability limit suggests an origin from spin-up and disruption of a loosely bound precursor within the past million years.
Gill Na+-K+-ATPase activity correlates with basolateral membrane lipid composition in seawater- but not freshwater-acclimated Arctic char (Salvelinus alpinus)
Authors: Bystriansky J. S. , Ballantyne J. S.
Published: October 2006

The successful migration of euryhaline teleost fish from freshwater to seawater requires the upregulation of gill Na+-K+-ATPase, an ion transport enzyme located in the basolateral membrane (BLM) of gill chloride cells. Following 39 days of seawater exposure, Arctic char had similar plasma sodium and chloride levels as individuals maintained in freshwater, indicating they had successfully acclimated to seawater. This acclimation was associated with an eightfold increase in gill Na+-K+-ATPase activity but only a threefold increase in gill Na+-K+-ATPase protein number, suggesting that other mechanisms may also modulate gill Na+-K+-ATPase activity. We therefore investigated the influence of membrane composition on Na+-K+-ATPase activity by examining the phospholipid, fatty acid, and cholesterol composition of the gill BLM from freshwater- and seawater-acclimated Arctic char. Mean gill BLM cholesterol content was significantly lower (∼22%) in seawater-acclimated char. Gill Na+-K+-ATPase activity in individual seawater Arctic char was negatively correlated with BLM cholesterol content and positively correlated with %phosphatidylethanolamine and overall %18:2n6 (linoleic acid) content of the BLM, suggesting gill Na+-K+-ATPase activity of seawater-acclimated char may be modulated by the lipid composition of the BLM and may be especially sensitive to those parameters known to influence membrane fluidity. Na+-K+-ATPase activity of individual freshwater Arctic char was not correlated to any membrane lipid parameter measured, suggesting that different lipid-protein interactions may exist for char living in each environment.
Role of glucocorticoid receptor in acclimation of killifish (Fundulus heteroclitus) to seawater and effects of arsenic
Authors: Shaw Joseph R. , Gabor Kristen , Hand Emily , Lankowski Alexander , Durant Lydia , Thibodeau Renee , Stanton Caitlin R. , Barnaby Roxanna , Coutermarsh Bonita , Karlson Katherine H. , Sato J. Denry , Hamilton Joshua W. , Stanton Bruce A.
Published: October 2006

Killifish are euryhaline teleosts that adapt to rapid changes in the salinity of the seawater. It is generally accepted that acclimation to seawater is mediated by cortisol activation of the glucocorticoid receptor (GR), which stimulates CFTR mRNA expression and CFTR-mediated Cl−secretion by the gill. Because there is no direct evidence in killifish that the GR stimulates CFTR gene expression, quantitative PCR studies were conducted to test the hypothesis that cortisol activation of GR upregulates CFTR mRNA expression and that this response is required for acclimation to seawater. Inhibition of the GR by RU-486 prevented killifish from acclimating to increased salinity and blocked the increase in CFTR mRNA. In contrast, inhibition of the mineralocorticoid receptor by spironolactone had no effect on acclimation to seawater. Thus acclimation to increased salinity in killifish requires signaling via the GR and includes an increase in CFTR gene expression. Because arsenic, a toxic metalloid that naturally occurs in the aquatic environment, has been shown to disrupt GR transcriptional regulation in avian and mammalian systems, studies were also conducted to determine whether arsenic disrupts cortisol-mediated activation of CFTR gene expression in this in vivo fish model and thereby blocks the ability of killifish to acclimate to increased salinity. Arsenic prevented acclimation to seawater and decreased CFTR protein abundance. However, arsenic did not disrupt the GR-induced increase in CFTR mRNA. Thus arsenic blocks acclimation to seawater in killifish by a mechanism that does not disrupt GR-mediated induction of CFTR gene expression.
Myofilament response to Ca2+ and Na+/H+ exchanger activity in sex hormone-related protection of cardiac myocytes from deactivation in hypercapnic acidosis
Authors: Bupha-Intr Tepmanas , Wattanapermpool Jonggonnee , Peña James R. , Wolska Beata M. , Solaro R. J.
Published: October 2006

Compared to sham-operated controls, myofilaments from hearts of ovariectomized (OVX) rats demonstrate an increase in Ca2+ sensitivity with no change in maximum tension (Wattanapermpool J and Reiser PJ. Am J Physiol 277: H467–H473, 1999). To test the significance of this modification in intact cells, we compared intracellular Ca2+ transients and shortening of ventricular myocytes isolated from sham and 10-wk OVX rats. There was a decrease in the peak Ca2+ transient with prolonged 50% decay time in OVX cardiac myocytes without changes in the resting intracellular Ca2+ concentration. Percent cell shortening was also depressed, and relaxation was prolonged in cardiac myocytes from OVX rats compared with shams. Ovariectomy induced a sensitization of the myofilaments to Ca2+. Hypercapnic acidosis suppressed the shortening of OVX myocytes to a lesser extent than that detected in shams. Moreover, a larger compensatory increase in %cell shortening was obtained in OVX myocytes during prolonged acidosis. The elevated compensation in cell shortening was related to a higher amount of increase in the amplitude of the Ca2+ transient in OVX myocytes. However, these differences in Ca2+ transients and %cell shortening were no longer evident in the presence of 1 μM cariporide, a specific inhibitor of Na+/H+ exchanger type 1 (NHE1). Our results indicate that deprivation of female sex hormones modulates the intracellular Ca2+ concentration in cardiac myocytes, possibly via an increased NHE1 activity, which may act in concert with Ca2+ hypersensitivity of myofilament activation as a determinant of sex differences in cardiac function.
Optimal frequency ranges for extracting information on cardiovascular autonomic control from the blood pressure and pulse interval spectrograms in mice
Authors: Baudrie Véronique , Laude Dominique , Elghozi Jean-Luc
Published: October 2006

The analysis of blood pressure (BP) and heart rate (HR) variability by spectral methods has proven a useful tool in many animal species for the assessment of the vagal and sympathetic contributions to oscillations of BP and HR. Continuous BP measurements obtained in mice by telemetry were used to characterize the spectral bandwidths of autonomic relevance by using an approach with no a priori. The paradigm was based on the autonomic blockades obtained with conventional drugs (atropine, prazosin, atenolol). The spectral changes were estimated in all of the combinations of spectral bandwidths. The effect of hydralazine was also tested using the same systematic analysis, to detect the zones of sympathetic activation resulting reflexly from the vasodilatory action of the drug. Two zones of interest in the study of the autonomic control of BP and HR were observed. The first zone covered the 0.15–0.60 Hz range of the systolic BP spectrum and corresponds to the low-frequency zone (or Mayer waves). This zone reflects sympathetic control since the power spectral density of this zone was significantly reduced with α1-adrenoceptor blockade (prazosin), while it was significantly amplified as a result of a reflex sympathetic activation (hydralazine). The second zone covered the 2.5–5.0 Hz range of the pulse interval spectrum and corresponded to the high-frequency zone (respiratory sinus arrhythmia) under vagal control (blocked by atropine). These zones are recommended for testing the autonomic control of circulation in mice.
Muscle pain induces task-dependent changes in cervical agonist/antagonist activity
Authors: Falla D. , Farina D. , Dahl M. Kanstrup , Graven-Nielsen T.
Published: October 2006

This study examined the effect of experimental neck muscle pain on the EMG-force relationship of cervical agonist and antagonist muscles. Surface EMG signals were detected from the sternomastoid, splenius capitis, and upper trapezius muscles bilaterally from 14 healthy subjects during cervical flexion and extension contractions of linearly increasing force from 0 to 60% of the maximum voluntary contraction (MVC). Measurements were performed before and after injection of 0.5 ml hypertonic and isotonic saline into either the sternomastoid or splenius capitis in two experimental sessions. EMG average rectified value (ARV) of the sternomastoid, splenius capitis, and upper trapezius muscles and the muscle fiber conduction velocity (CV) of the sternomastoid muscle were estimated at 5% MVC force increments. During cervical flexion with injection of hypertonic saline in sternomastoid, ARV of sternomastoid was lower on the side of pain in the force range 25–60% MVC ( P < 0.05) and was associated with a bilateral reduction of splenius capitis and upper trapezius ARV ( P < 0.01). During cervical extension, injection of hypertonic saline in splenius capitis resulted in lower estimates of splenius capitis ARV on the painful side from 45 to 60% MVC ( P < 0.05), which was associated with a bilateral increase in upper trapezius ARV estimates from 50 to 60% MVC ( P < 0.001). However, no significant change was identified for estimates of sternomastoid ARV. Experimentally induced neck muscle pain resulted in task-dependent changes in cervical agonist/antagonist activity without modifications in muscle fiber CV.
Circulating Leukocyte-Derived Microparticles Predict Subclinical Atherosclerosis Burden in Asymptomatic Subjects
Authors: Chironi Gilles , Simon Alain , Hugel Bénédicte , Del Pino Muriel , Gariepy Jérôme , Freyssinet Jean-Marie , Tedgui Alain
Published: October 2006

Objective—

To clarify circulating microparticles (MP) relationships with preclinical atherosclerosis.

Methods and Results—

In 216 subjects without cardiovascular disease, we assessed: (1) annexin V-positive, platelet-derived, endothelium-derived and leukocyte-derived circulating MP by capture on annexin V, anti-GPIb, anti-CD105, and anti-CD11a antibody-coated wells, respectively; (2) Framingham risk, metabolic syndrome, and low-grade inflammation by risk factors measurement including hsCRP; and (3) subclinical atherosclerosis by ultrasound examination of carotid, abdominal aorta, and femoral arteries. Number of sites with plaque ranged from 0 to 3 and plaque burden was classified into 0 to 1 or 2 to 3 sites disease. Leukocyte-derived MP level was higher in the presence than in the absence of moderate to high Framingham risk (
P
<0.05), metabolic syndrome (
P
<0.01), high C-reactive protein (CRP) (
P
<0.05), or 2- to 3-sites disease (
P
<0.01), and correlated positively with number of metabolic syndrome components (
P
<0.001), tertiles of fibrinogen (
P
<0.001), and number of diseased sites (
P
<0.01). In multivariate analysis, 2- to 3-sites disease was independently associated with leukocyte-derived MP level (
P
<0.05), Framingham risk (
P
<0.001), and metabolic syndrome (
P
<0.01). None of the other MP types correlated with risk markers or atherosclerosis.

Conclusions—

Leukocyte-derived MP, identified by affinity for CD11a, are increased in subjects with ultrasound evidence of subclinical atherosclerosis, unveiling new directions for atherosclerosis research.
Macrophage Phospholipid Transfer Protein Deficiency and ApoE Secretion
Authors: Liu Ruijie , Hojjati Mohammad R. , Devlin Cecilia M. , Hansen Inge H. , Jiang Xian-Cheng
Published: October 2006

Objective—

PLTP and apoE play important roles in lipoprotein metabolism and atherosclerosis. It is known that formation of macrophage-derived foam cells (which highly express PLTP and apoE) is the critical step in the process of atherosclerosis. We investigated the relationship between PLTP and apoE in macrophages and the atherogenic relevance in a mouse model.

Methods and Results—

We transplanted PLTP-deficient mouse bone marrow into apoE-deficient mice (PLTP
−/−
→apoE
−/−
), creating a mouse model with PLTP deficiency and apoE expression exclusively in the macrophages. We found that PLTP
−/−
→apoE
−/−
mice have significantly lower PLTP activity, compared with controls (WT→apoE
−/−
; 20%,
P
<0.01). On a Western diet, PLTP
−/−
→apoE
−/−
mice have significantly lower plasma apoE than that of WT→apoE
−/−
mice (63%,
P
<0.001), and PLTP-deficient macrophages secrete significantly less apoE than WT macrophages (44%,
P
<0.01). Moreover, PLTP
−/−
→apoE
−/−
mice have significantly higher plasma cholesterol (98%,
P
<0.001) and phospholipid (107%,
P
<0.001) than that of WT→apoE
−/−
mice, thus increasing atherosclerotic lesions in the aortic arch and root (403%,
P
<0.001), as well as the entire aorta (298%,
P
<0.001).

Conclusions—

Macrophage PLTP deficiency causes a significant reduction of apoE secretion from the cells, and this in turn promotes the accumulation of cholesterol in the circulation and accelerates the development of atherosclerosis.
Time Course of Degradation of Cardiac Troponin I in Patients With Acute ST-Elevation Myocardial Infarction
Authors: Madsen Lene H. , Christensen Geir , Lund Terje , Serebruany Victor L. , Granger Chris B. , Hoen Ingvild , Grieg Zanina , Alexander John H. , Jaffe Allan S. , Van Eyk Jennifer E. , Atar Dan
Published: October 2006

Although measurement of troponin is widely used for diagnosing acute myocardial infarction (AMI), its diagnostic potential may be increased by a more complete characterization of its molecular appearance and degradation in the blood. The aim of this study was to define the time course of cardiac troponin I (cTnI) degradation in patients with acute ST-elevation myocardial infarction (STEMI). In the ASSENT-2 substudy, 26 males hospitalized with STEMI were randomized to 2 different thrombolytic drugs within 6 hours after onset of symptoms. Blood samples were obtained just before initiation of thrombolysis and at 30 minutes intervals (7 samples per patient). Western blot analysis was performed using anti-cTnI antibodies and compared with serum concentrations of cTnI. All patients exceeded the cTnI cutoff for AMI during the sampling period; at initiation of therapy, 23 had elevated cTnI values. All patients demonstrated 2 bands on immunoblot: intact cTnI and a single degradation product as early as 90 minutes after onset of symptoms. On subsequent samples, 15 of 26 patients showed multiple degradation products with up to 7 degradation bands. The appearance of fragments was correlated with higher levels of cTnI (
P
<0.001) and time to initiation of treatment (
P
=0.058). This study defines for the first time the initial time course of cTnI degradation in STEMI. Intact cTnI and a single degradation product were detectable on immunoblot as early as 90 minutes after onset of symptoms with further degradation after 165 minutes. Infarct size and time to initiation of treatment was the major determinant for degradation.
Diurnal Cycle of Shallow and Deep Convection for a Tropical Land and an Ocean Environment and Its Relationship to Synoptic Wind Regimes
Authors: Pereira L. Gustavo , Rutledge Steven A.
Published: October 2006

The characteristics of shallow and deep convection during the Tropical Rainfall Measuring Mission/Large-Scale Biosphere–Atmosphere Experiment in Amazonia (TRMM/LBA) and the Eastern Pacific Investigation of Climate Processes in the Coupled Ocean–Atmosphere System (EPIC) are evaluated in this study. Using high-quality radar data collected during these two tropical field experiments, the reflectivity profiles, rain rates, fraction of convective area, and fraction of rainfall volume in each region are examined. This study focuses on the diurnal cycle of shallow and deep convection for the identified wind regimes in both regions.

The easterly phase in TRMM/LBA and the northerly wind regime in EPIC were associated with the strongest convection, indicated by larger rain rates, higher reflectivities, and deeper convective cores compared to the westerly phase in TRMM/LBA and the southerly regime in EPIC. The diurnal cycle results indicated that convection initiates in the morning and peaks in the afternoon during TRMM/LBA, whereas in the east Pacific the diurnal cycle of convection is very dependent on the wind regime. Deep convection in the northerly regime peaks around midnight, nearly 6 h before its southerly regime counterpart. Moreover, the northerly regime of EPIC was dominated by convective rainfall, whereas the southerly regime was dominated by stratiform rainfall. The diurnal variability was more pronounced during TRMM/LBA than in EPIC. Shallow convection was associated with 10% and 3% of precipitation during TRMM/LBA and EPIC, respectively.
Efficient Approximate Techniques for Integrating Stochastic Differential Equations
Authors: Hansen James A. , Penland Cecile
Published: October 2006

The delicate (and computationally expensive) nature of stochastic numerical modeling naturally leads one to look for efficient and/or convenient methods for integrating stochastic differential equations. Concomitantly, one may wish to sensibly add stochastic terms to an existing deterministic model without having to rewrite that model. In this note, two possibilities in the context of the fourth-order Runge–Kutta (RK4) integration scheme are examined. The first approach entails a hybrid of deterministic and stochastic integration schemes. In these examples, the hybrid RK4 generates time series with the correct climatological probability distributions. However, it is doubtful that the resulting time series are approximate solutions to the stochastic equations at every time step. The second approach uses the standard RK4 integration method modified by appropriately scaling stochastic terms. This is shown to be a special case of the general stochastic Runge–Kutta schemes considered by Ruemelin and has global convergence of order one. Thus, it gives excellent results for cases in which real noise with small but finite correlation time is approximated as white. This restriction on the type of problems to which the stochastic RK4 can be applied is strongly compensated by its computational efficiency.
Storm Morphology and Rainfall Characteristics of TRMM Precipitation Features
Authors: Nesbitt Stephen W. , Cifelli Robert , Rutledge Steven A.
Published: October 2006

Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR), TRMM Microwave Imager (TMI), and Visible and Infrared Scanner (VIRS) observations within the Precipitation Feature (PF) database have been analyzed to examine regional variability in rain area and maximum horizontal extent of rainfall features, and role of storm morphology on rainfall production (and thus modes where vertically integrated heating occurs). Particular attention is focused on the sampling geometry of the PR and the resulting impact on PF statistics across the global Tropics. It was found that 9% of rain features extend to the edge of the PR swath, with edge features contributing 42% of total rainfall. However, the area (maximum dimension) distribution of PR features is similar to the wider-swath TMI up until a truncation point of nearly 30 000 km2 (250 km), so a large portion of the feature size spectrum may be examined using the PR as with past ground-based studies.

This study finds distinct differences in land and ocean storm morphology characteristics, which lead to important differences in rainfall modes regionally. A larger fraction of rainfall comes from more horizontally and vertically developed PFs over land than ocean due to the lack of shallow precipitation in both relative and absolute frequency of occurrence, with a trimodal distribution of rainfall contribution versus feature height observed over the ocean. Mesoscale convective systems (MCSs) are found to be responsible for up to 90% of rainfall in selected land regions. Tropicswide, MCSs are responsible for more than 50% of rainfall in almost all regions with average annual rainfall exceeding 3 mm day−1. Characteristic variability in the contribution of rainfall by feature type is shown over land and ocean, which suggests new approaches for improved convective parameterizations.
High Winds Generated by Bow Echoes. Part I: Overview of the Omaha Bow Echo 5 July 2003 Storm during BAMEX
Authors: Wakimoto Roger M. , Murphey Hanne V. , Nester Albert , Jorgensen David P. , Atkins Nolan T.
Published: October 2006

An analysis of a bow echo that produced damaging winds exceeding F1 in intensity on the Fujita scale near Omaha, Nebraska, is shown. Part I of this study presents a combination of airborne Doppler-derived wind syntheses with a comprehensive damage survey in order to document the generation of strong winds at the surface. A detailed kinematic analysis of the evolution of a quasi-linear convective system into a bow-shaped and, subsequently, a spearhead echo is shown for the first time. It is hypothesized that a large, cyclonic bookend vortex (70–80 km in diameter) north of the bow apex enhanced the rear-inflow jet and initiated the “bowing process.” A hook-shaped echo and mesovortex formed at the apex of a bowed segment of the convective line and was located to the north of the swath of strong damage rated greater than F1 in damage intensity. The peak single-Doppler radial velocity recorded by the tail radar was 43 m s−1 in the low-level outflow near the apex of the bow echo. The regions of the strongest single-Doppler velocities at the lowest grid level were not always associated with the most intense damage at the surface. This discrepancy may be related to the development of a stable nocturnal boundary layer that prevented the strong outflow winds from reaching the surface. An intensifying rear-inflow jet was revealed in vertical cross sections through the bow echo. The relationship between mesovortices and strong surface winds is examined in Part II.
An Observational Examination of Long-Lived Supercells. Part II: Environmental Conditions and Forecasting
Authors: Bunkers Matthew J. , Johnson Jeffrey S. , Czepyha Lee J. , Grzywacz Jason M. , Klimowski Brian A. , Hjelmfelt Mark R.
Published: October 2006

The local and larger-scale environments of 184 long-lived supercell events (containing one or more supercells with lifetimes ≥4 h; see Part I of this paper) are investigated and subsequently compared with those from 137 moderate-lived events (average supercell lifetime 2–4 h) and 119 short-lived events (average supercell lifetime ≤2 h) to better anticipate supercell longevity in the operational setting. Consistent with many previous studies, long-lived supercells occur in environments with much stronger 0–8-km bulk wind shear than what is observed for short-lived supercells; this strong shear leads to significant storm-relative winds in the mid- to upper levels for the longest-lived supercells. Additionally, the bulk Richardson number falls into a relatively narrow range for the longest-lived supercells—ranging mostly from 5 to 45. The mesoscale to synoptic-scale environment can also predispose a supercell to be long or short lived, somewhat independent of the local environment. For example, long-lived supercells may occur when supercells travel within a broad warm sector or else in close proximity to mesoscale or larger-scale boundaries (e.g., along or near a warm front, an old outflow boundary, or a moisture/buoyancy axis), even if the deep-layer shear is suboptimal. By way of contrast, strong atmospheric forcing can result in linear convection (and thus shorter-lived supercells) in a strongly sheared environment that would otherwise favor discrete, long-lived supercells.
A Dynamic Decision Model Applied to Hurricane Landfall
Authors: Regnier Eva , Harr Patrick A.
Published: October 2006

The decision to prepare for an oncoming hurricane is typically framed as a static cost:loss problem, based on a strike-probability forecast. The value of waiting for updated forecasts is therefore neglected. In this paper, the problem is reframed as a sequence of interrelated decisions that more accurately represents the situation faced by a decision maker monitoring an evolving tropical cyclone. A key feature of the decision model is that the decision maker explicitly anticipates and plans for future forecasts whose accuracy improves as lead time declines. A discrete Markov model of hurricane travel is derived from historical tropical cyclone tracks and combined with the dynamic decision model to estimate the additional value that can be extracted from existing forecasts by anticipating updated forecasts, rather than incurring an irreversible preparation cost based on the instantaneous strike probability. The value of anticipating forecasts depends on the specific alternatives and cost profile of each decision maker, but conceptual examples for targets at Norfolk, Virginia, and Galveston, Texas, yield expected savings ranging up to 8% relative to repeated static decisions. In real-time decision making, forecasts of improving information quality could be used in combination with strike-probability forecasts to evaluate the trade-off between lead time and forecast accuracy, estimate the value of waiting for improving forecasts, and thereby reduce the frequency of false alarms.
Caught in a Balancing Act: Parents’ Dilemmas Regarding Their ADHD Child’s Treatment With Stimulant Medication
Authors: Hansen Dana Lee , Hansen Ebba Holme
Published: October 2006

The authors explored parents’ perceptions of and everyday experiences with the stimulant medication used to treat their child’s attention deficit hyperactivity disorder (ADHD) in this phenomenological study. They elicited experiences through semistructured interviews with 10 Canadian parents of children with ADHD. In the interviews, parents revealed the meaning the stimulant medication had taken on in the context of their everyday lives. Through the interview analysis, dilemma emerged as the dominant theme. Parents were caught in a dynamic balancing act, as they considered the medication’s desirable and undesirable effects in various settings. In addition, parents shared their expectations regarding the medication’s role in their child’s future. The study’s findings reinforce the necessity of further qualitative research in this area, given the growing number of families around the globe whose children have been diagnosed with ADHD.
“Never Again” Stories of Nurses: Dilemmas in Nursing Practice
Authors: Wolf Zane Robinson , Zuzelo Patti Rager
Published: October 2006

The authors describe significant turning points immanent in “never again” stories that practicing nurses, having participated in previously, vowed not to allow to recur during future, similar situations. Nurses submitted written accounts of critical, “never again” situations. The authors used critical incident technique and employed Colaizzi’s approach to reveal the essential structure. Patient outcomes were fatal, close calls, dehumanizing, or isolating. Never again stories incorporated ethical dilemmas, deficits in nurses’ knowledge, lack of confidence in clinical abilities, and failure to act correctly. Patients’ welfare was the center of accounts. Circumstances threatened patients’ and family members’ trust in nurses and other providers. Patients’ wishes were denied because of haste, providers’ arrogance, or providers’ desire not to be inconvenienced. Nurses’ emotions mirrored a sense of failed responsibility for patients. Regret was tempered by nurses’ pledges. Critical incidents revealed dilemmas in which nurses’ autonomous clinical practice was constrained by feelings of powerlessness.
ZAP-70 enhances B-cell–receptor signaling despite absent or inefficient tyrosine kinase activation in chronic lymphocytic leukemia and lymphoma B cells
Authors: Gobessi Stefania , Laurenti Luca , Longo Pablo G. , Sica Simona , Leone Giuseppe , Efremov Dimitar G.
Published: October 2006

Expression of ZAP-70 is an important negative prognostic factor in chronic lymphocytic leukemia (CLL). This protein tyrosine kinase is a key mediator of T-cell receptor (TCR) signaling and is structurally homologous to Syk, which plays an analogous role in B-cell receptor (BCR) signaling. Recent studies indicate that ZAP-70 may participate in BCR signaling as well, but the mechanism of action is not completely understood. We have now compared antigen receptor-induced activation of ZAP-70 in B cells and T cells by analyzing phosphorylation of critical regulatory tyrosine residues. We show that BCR-mediated activation of ZAP-70 is very inefficient in CLL and lymphoma B cells and is negligible when compared to activation of Syk. Despite the inefficient catalytic activation, the ability of ZAP-70 to recruit downstream signaling molecules in response to antigen receptor stimulation appeared relatively preserved. Moreover, ectopic expression of ZAP-70 enhanced and prolonged activation of several key mediators of BCR signaling, such as the Syk, ERK, and Akt kinases, and decreased the rate of ligand-mediated BCR internalization. We conclude that the role of ZAP-70 in BCR signaling is quite distinct from its role in TCR signaling and is likely mediated by inhibition of events that terminate the signaling response.
Prospective feasibility analysis of reduced-intensity conditioning (RIC) regimens for hematopoietic stem cell transplantation (HSCT) in elderly patients with acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS)
Authors: Estey Elihu , de Lima Marcos , Tibes Raoul , Pierce Sherry , Kantarjian Hagop , Champlin Richard , Giralt Sergio
Published: October 2006

To prospectively assess the applicability of reduced-intensity conditioning hematopoietic stem cell transplantation (RIC-HSCT), we wrote a protocol in which all untreated patients 50 years or older with acute myeloid leukemia (AML) and unfavorable cytogenetics would be evaluated during induction for a possible RIC-HSCT in first complete remission (CR1). Ninety-nine of 259 patients entered CR. Fifty-three of the 99 were seen by the Transplant Service with the remainder not seen because of illness, lack/unavailability of siblings, refusal, or, primarily, unclear reasons (21 patients). A donor was identified for 26 patients (21 sibling, 5 unrelated) with RIC-HSCT performed in 14 (13 sibling). Results in consulted patients suggested that 50% or fewer of the 85 patients who did not undergo transplantation were potential transplant candidates. We attempted to find one or more chemotherapy pair-mates for each patient who underwent transplantation based on cytogenetics, age, and a relapse-free survival (RFS) time that was more than or equal to the time from CR1 to RIC-HSCT in the patient who underwent transplantation. Thirty-two of the 39 matches favored (longer RFS) RIC-HSCT and 7, chemotherapy. The probability that the corresponding beta distribution was different than expected (ie, that RIC-HSCT was superior) was 0.99 (P = .004). Results were similar with respect to survival. While RIC-HSCT thus seems of interest, methods are needed to extend its applicability.
Engineered anti-CD70 antibody with multiple effector functions exhibits in vitro and in vivo antitumor activities
Authors: McEarchern Julie A. , Oflazoglu Ezogelin , Francisco Leigh , McDonagh Charlotte F. , Gordon Kristine A. , Stone Ivan , Klussman Kerry , Turcott Eileen , van Rooijen Nico , Carter Paul , Grewal Iqbal S. , Wahl Alan F. , Law Che-Leung
Published: October 2006

Antigens expressed on malignant cells in the absence of significant expression on normal tissues are highly desirable targets for therapeutic antibodies. CD70 is a TNF superfamily member whose normal expression is highly restricted but is aberrantly expressed in hematologic malignancies including non-Hodgkin lymphoma (NHL), Hodgkin disease, and multiple myeloma. In addition, solid tumors such as renal cell carcinoma, nasopharyngeal carcinoma, thymic carcinoma, meduloblastoma, and glioblastoma express high levels of this antigen. To functionally target CD70-expressing cancers, a murine anti-CD70 monoclonal antibody was engineered to contain human IgG1 constant domains. The engineered antibody retained the binding specificity of the murine parent monoclonal antibody and was shown to induce Fc-mediated effector functions including antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity, and antibody-dependent cellular phagocytosis in vitro. Further, administration of this antibody significantly prolonged survival of severe combined immunodeficient (SCID) mice bearing CD70+ disseminated human NHL xenografts. Survival of these mice was dependent upon the activity of resident effector cells including neutrophils, macrophages, and natural killer (NK) cells. These data suggest that an anti-CD70 antibody, when engineered to contain human IgG1 constant domains, possesses effector cell–mediated antitumor activity and has potential utility for anticancer therapy.
Unrelated donor bone marrow transplantation for the treatment of Fanconi anemia
Authors: Wagner John E. , Eapen Mary , MacMillan Margaret L. , Harris Richard E. , Pasquini Ricardo , Boulad Farid , Zhang Mei-Jie , Auerbach Arleen D.
Published: October 2006

Bone marrow transplantation (BMT) is the only known cure for the hematologic manifestations of Fanconi anemia (FA). Potential benefits of unrelated donor BMT for FA, however, have been severely limited by graft rejection and treatment-related mortality with resultant poor survival. Therefore, we evaluated the impact of potential prognostic factors on hematopoietic recovery, graft-versus-host disease (GVHD), and mortality in 98 recipients of unrelated donor BMT who received transplants between 1990 and 2003. Probabilities of neutrophil (89% vs 69%; P = .02) and platelet (74% vs 23%; P < .001) recovery were higher after fludarabine-containing regimens than nonfludarabine-containing regimens. Risks of acute GVHD (relative risk [RR], 4.29; P < .001) were higher with non–T-cell–depleted grafts. The day-100 mortality rate was significantly higher after nonfludarabine-containing regimens than fludarabine-containing regimens (65% vs 24%, respectively; P < .001). Corresponding 3-year adjusted overall survival rates were 13% versus 52% (P < .001). In addition, mortality was higher in recipients who were older (> 10 years), who were cytomegalovirus (CMV) seropositive, and who received more than 20 blood product transfusions before BMT. Based on these results, significant practice changes are suggested: use of a fludarabine-containing conditioning regimen in the context of T-cell–depleted marrow allografts, and earlier referral for transplantation prior to excessive transfusions in patients with marrow failure.
Laboratory tests of oviposition by the African malaria mosquito, Anopheles gambiae, on dark soil as influenced by presence or absence of vegetation
Authors: Huang Juan , Walker Edward D , Otienoburu Philip E , Amimo Fred , Vulule John , Miller James R
Published: October 2006

Background

Physical objects like vegetation can influence oviposition by mosquitoes on soil or water substrates. Anopheles gambiae s. l. is generally thought to utilize puddles over bare soil as its prime larval habitat and to avoid standing water populated with vegetation. In Kisian, Kenya near Kisumu, water often pools in grassy drainage areas both during and after periods of infrequent rains, when typical puddle habitats become scarce because of drying. This raised the question of whether An. gambiae has the behavioural flexibility to switch ovipositional sites when puddles over bare soil are unavailable.

Methods

To test whether presence and height of grasses influenced oviposition, wild-caught gravid An. gambiae s. l. were offered paired choices between wet, bare soil and wet soil populated with mixed grasses or grasses of differing height. No-choice tests were also conducted by giving females either grassy soil or bare soil.

Results

In choice tests, females laid four times more eggs on bare, wet soil than soil populated with grasses. However in no-choice tests, egg output was not significantly different whether grasses were present or not. Females laid significantly more eggs on soil populated with short grass than with medium, or tall grass.

Conclusion

This work shows An. gambiae s. l. has the capacity to oviposit into grassy aquatic habitats when typical puddles over bare soil are unavailable. This knowledge will need to be considered in the design and implementation of programmes aimed at reducing malaria transmission by suppression of An. gambiae s. l. immatures.
Severity of the Catabolic Condition Differentially Modulates Hypothalamic Expression of Growth Hormone-Releasing Hormone in the Fasted Mouse: Potential Role of Neuropeptide Y and Corticotropin-Releasing Hormone
Authors: Luque Raul M. , Park Seungjoon , Kineman Rhonda D.
Published: October 2006

To determine whether the severity of the catabolic condition differentially regulates the GH axis, male mice were either fed ad libitum or fasted for 12, 24, and 48 h. Hypothalami, pituitaries, and stomachs were collected for assessment of mRNA levels by quantitative real-time RT-PCR, and blood collected for measurement of plasma hormone and metabolite levels by commercial assay kits. Overnight (12 h) fasting resulted in a significant suppression of circulating glucose, insulin, IGF-I, and leptin levels and an increase in corticosterone, free fatty acids, and n-octanoyl ghrelin levels, and these directional changes were maintained at the 24- and 48-h time points. Fasting (24 h) also increased circulating GH levels, which was associated with an increase in pituitary mRNA levels for GHRH receptor and ghrelin receptor and a decrease in mRNA levels for somatostatin (SST) receptor (SSTR) subtypes, SSTR2, SSTR3, and SSTR5, where the changes in ghrelin receptor and SSTR expression persisted after 48 h fasting. Hypothalamic SST mRNA levels were not altered by fasting, whereas there was a transient rise in stomach SST mRNA levels 24 h after food withdrawal. In contrast, there was a biphasic effect of fasting on GHRH expression. GHRH mRNA levels were significantly elevated at 12 and 24 h but fell to ∼50% of fed controls 48 h after food withdrawal. A sequential rise in hypothalamic neuropeptide Y (NPY) and CRH mRNA levels preceded the fall in GHRH expression, where fasting-induced changes in CRH and GHRH mRNA levels were not observed in 48-h-fasted NPY knockout mice. These observations, in light of previous reports showing both NPY and CRH can inhibit GHRH expression and GH release, suggest that these neuronal systems may work in concert to control the ultimate impact of fasting on GH axis function.