bluuebunny/crossref_metadata_2025 huggingface dataset:
The course of PTSD symptoms among Gulf War veterans: A growth mixture modeling approach
Authors: Orcutt Holly K. , Erickson Darin J. , Wolfe Jessica
Published: May 2004

Relatively little is known about the course of PTSD symptoms over time following trauma exposure. Accordingly, this study utilized a specialized structural equation modeling approach, growth mixture modeling, to examine the trajectory of PTSD symptoms across three time points in a sample of Gulf War veterans (nat Time 1 = 2,949,nat Time 2 = 2,313, andnat Time 3 = 1,327). Results were most consistent with a two‐group model suggesting that the course of PTSD symptoms following the Gulf War was best characterized by two distinct growth curves: (1) low levels of PTSD symptoms with little increase over time and (2) higher levels of initial symptoms with a significant increase over time. Thus, it appears that response to Gulf War experiences is not homogeneous, and that a subset of individuals may experience relatively more PTSD symptoms over time. In addition, men, Whites, those reporting more education, and those reporting less combat exposure had a significantly higher probability of being classified into the less symptomatic group.
Adult sexual assault: Prevalence, symptomatology, and sex differences in the general population
Authors: Elliott Diana M. , Mok Doris S. , Briere John
Published: May 2004

The prevalence and impact of adult sexual assault (ASA) were examined in a stratified random sample of the general population. Among 941 participants, ASA was reported by 22% of women and 3.8% of men. Multivariate risk factors for ASA included a younger age, being female, having been divorced, sexual abuse in childhood, and physical assault in adulthood. Childhood sexual abuse was especially common among sexually assaulted men and women (61 and 59%, respectively). ASA victims were more symptomatic than their nonassaulted cohorts on all scales of the Trauma Symptom Inventory (TSI; J. Briere, 1995), despite an average of 14 years having passed since the assault. Assaulted men reported greater symptomatology than assaulted women, whereas nonassaulted men reported less symptomatology than nonassaulted women.
Posttraumatic stress disorder symptom checklist: Factor structure and English–Spanish measurement invariance
Authors: Marshall Grant N.
Published: May 2004

This study used confirmatory factor analysis to compare alternative models of the structure of posttraumatic distress symptoms as measured by the Posttraumatic Stress Disorder Checklist—Civilian version (PCL‐C; F. W. Weathers, B. T. Litz, D. S. Herman, J. A. Huska, & T. M. Keane, 1993). Data were derived from English‐ (N = 299) and Spanish‐speaking (N = 120) samples of young adult survivors of community violence recruited following hospitalization for physical injuries. The best fit to the data was a four‐factor model measuring correlated dimensions of reexperiencing, avoidance, emotional numbing, and hyperarousal. English‐ and Spanish‐language versions of the PCL‐C showed general measurement equivalence.
Characteristics and content of intrusive memories in PTSD and their changes with treatment
Authors: Hackmann Ann , Ehlers Anke , Speckens Anne , Clark David M.
Published: May 2004

Although intrusive reexperiencing is a core symptom of postraumatic stress disorder (PTSD), relatively little is known about its phenomenology. The present study assessed the characteristics and content of intrusive trauma memories in 22 patients with PTSD, and followed their changes in the course of cognitive behavioral treatment. Patients had a small number of different intrusive memories (1–4, M = 2.2) that occurred in an invariable, repetitive way. The intrusions were distressing and had a vivid perceptual content. They appeared to the patient to be happening in the “here and now.” With therapy, the frequency, vividness, distress, and nowness of the intrusions faded gradually. There was no exacerbation with imaginal reliving. The content of intrusions was classified by raters to test A. Ehlers et al.'s (2002) hypothesis that intrusive memories are usually of warning stimuli that signalled the moments with the greatest emotional impact. The results were consistent with this hypothesis.
A concise measure of anger in combat‐related posttraumatic stress disorder
Authors: Forbes David , Hawthorne Graeme , Elliott Peter , McHugh Tony , Biddle Dirk , Creamer Mark , Novaco Raymond W.
Published: May 2004

There is a need for a brief specific measure of anger for use in assessment of posttraumatic mental health problems. One unpublished short scale is the Dimensions of Anger Reactions (DAR; R. Novaco, 1975). This study examined the psychometric properties of the DAR using intake and 12‐month data for 192 Australian Vietnam veterans with combat‐related PTSD. Results showed the DAR to be unidimensional, reliable, and sensitive to change over time, and removal of two items improved the scale's properties. The DAR measures anger disposition directed towards others. Assessment of convergent validity indicated that the DAR primarily measures Trait Anger. Results suggest that the DAR is a psychometrically strong measure, potentially useful for the evaluation of anger in PTSD.
Suicidality of Chronic Schizophrenic Patients in Long-Term Community Care
Authors: Kallert Thomas W. , Leisse Matthias , Winiecki Peter
Published: May 2004

Summary: In the provision of mental health care for chronic schizophrenic patients, the specific problems and requirements of long-term community care of suicidal behavior is an area of research not yet fully explored. This study focuses on a 4 ½-year prospective assessment of normative and subjective needs for care related to this specific area for a cohort living in the Dresden region (Germany). One significant result of this study shows the constant high level of needs for care in the area of suicidal behavior imposed on community services by 30-40% of this diagnostic group. Furthermore, the study identified a special high-risk subgroup for suicides as well as specific needs for care. This subgroup is characterized by clinical reasons for the index hospitalization (suicidal risk or attempt) as well as by psychopathological features (suicidal thoughts and higher levels of anxiety/depression) 1 month after release from index hospitalization. Four items of care were rated as potentially effective for addressing suicidality in the community setting: clinical assessment, increased supervision or systematic recording of (suicidal) behavior, medication, and a sheltered environment. Because these care measures are provided, the percentage of unmet normative needs for the area of suicidal behavior was rather low. Due to limitations of the instrument used for assessment of normative needs, the Needs for Care Assessment (NFCAS), the care measures most frequently provided do not define a quality standard of community care for this problem. A subjective needs assessment differing from the normative approach has to be integrated in establishing guidelines for effective community care.
The Impact of Suicide Prevention Centers on the Suicide Rate in the Canadian Provinces
Authors: Leenaars Antoon A. , Lester David
Published: May 2004

Summary: A study by Leenaars and Lester (1995) found that suicide prevention centers in the provinces of Canada in 1985 had a preventive, but nonsignificant, impact on the suicide rates of the provinces. The present study replicated that study for 1994-1998 and found a similar preventive impact, although weak, of suicide prevention centers on the provincial suicide rates.
Familial Study of Suicidal Behavior Among Adolescents in Slovenia
Authors: Marušič Andrej , Roškar Saška , Hughes Roderick H.
Published: May 2004

Summary: The number of adolescents who attempt or complete suicide is increasing. Risk factors range from mental disorders, to problems at school, family problems, or difficulties in establishing relationships. A further important, and too often underestimated, risk factor for adolescent suicide is the presence of suicidal behavior in the adolescent's family. We investigated 184 high school adolescents in a region in Slovenia with a high suicide rate (30/100,000/year). They were questioned by means of an anonymous questionnaire about the presence of suicidal behavior in their relatives and about the presence of suicidal thoughts, plans, and acts in themselves. The results revealed that 13% of the adolescents studied had a relative who had attempted suicide and a further 9% of the adolescents had lost a relative due to suicide. About half of all females and almost a third of males had had suicidal thoughts (differences between sexes were statistically significant: χ2= 6.13; p < .01). Attempted suicide among relatives was positively correlated with the presence of suicidal plans among adolescents (Φ = 0.15; p < .05). This correlation proved to be even stronger and statistically more significant in men when we split the sample by gender. All variables (suicidal thoughts, suicidal plans, and suicide attempts) in the adolescent males positively correlated with attempted suicide among their relatives (Φ = 0.28, p < .01; Φ = 0.26, p < .05; Φ = 0.34, p < .01; respectively). Our results speak in favor of a higher risk of suicidal behavior among adolescents with suicidal behavior in their families.
On the consistency of trends in radiation and temperature records and implications for the global hydrological cycle
Authors: Wild Martin , Ohmura Atsumu , Gilgen Hans , Rosenfeld Daniel
Published: June 2004

Several studies indicate that incident shortwave radiation at land surfaces has significantly decreased between 1960 and 1990. Despite this, land temperature has increased by 0.4°C over the same period. From a surface energy balance perspective, this counterintuitive behaviour can be resolved either 1) through an increase in the downward longwave radiation which outweighs the decreased insolation or 2) through a decrease of surface evaporation and associated reduced evaporative surface cooling. It is suggested that 1) may not be large enough, so that the available energy for evaporation may rather have decreased than increased over the period considered. This is in line with an analysis of observed surface net radiation records. The inferred decrease of evaporation would further imply that the observed intensification of the hydrological cycle over extratropical land has been more likely due to increased moisture advection from the oceans than due to increased local moisture release through evaporation.
Pattern and trend analysis of temperature in a set of seasonal ensemble simulations
Authors: Zhao Mei , Dirmeyer Paul A.
Published: June 2004

Eighteen years of seasonal 10‐member ensemble simulations have been performed with observed sea surface temperature (SST) to assess the ability of dynamical models to predict seasonal‐interannual climate variations during boreal summer. In addition, test cases have been designed to assess the role in climate trends, predictability of land initial conditions, systematic errors of precipitation and radiation fluxes at the land surface, and increasing CO2. The model reproduces a global warming trend in surface temperature similar to that observed. This appears to be attributable to the influence of SST. However, surface flux replacement and atmospheric initialization can reduce the SST‐driven trend even while improving the spatial pattern of surface air temperature. The results also show that land surface interaction has an effect both on surface temperature and the higher levels of the troposphere. However, realistically increasing CO2 concentrations have little impact in these seasonal simulations.
Observation of O+ 4P‐4D0 lines in proton aurora over Svalbard
Authors: Ivchenko N. , Galand M. , Lanchester B. S. , Rees M. H. , Lummerzheim D. , Furniss I. , Fordham J.
Published: May 2004

Spectra of a proton aurora event show lines of O+ 4P‐4D0 multiplet (4639–4696 Å) enhanced relative to the N2+1N(0,2) compared to normal electron aurora. Conjugate satellite particle measurements are used as input to electron and proton transport models, to show that p/H precipitation is the dominant source of both the O+ and N2+1N emissions. The emission cross‐section of the multiplet in p collisions with O and O2 estimated from published work does not explain the observed O+ brightness, suggesting a higher emission cross‐section for low energy p impact on O.
Structural factors controlling the coseismic rupture zone of the 1973 Nemuro‐Oki earthquake, the southern Kuril Trench seismogenic zone
Authors: Nakanishi Ayako , Smith Alex J. , Miura Seiichi , Tsuru Tetsuro , Kodaira Shuichi , Obana Koichiro , Takahashi Narumi , Cummins Phil R. , Kaneda Yoshiyuki
Published: May 2004

The Kuril Trench is an active seismogenic zone where historic great earthquakes have occurred repeatedly with temporal and spatial regularities. This paper presents the results of a wide‐angle ocean bottom seismographic (OBS) survey across the coseismic rupture zone of the 1973 Nemuro‐Oki earthquake (Mw = 7.8), together with thermal modeling. The main purpose of this study is to understand the crustal and thermal controls on the Kuril seismogenic zone. Revealing structures that can be controlling factors of a megathrust earthquake helps in estimating earthquake hazards. We focus specifically on the precise structure of the seismogenic interface. Our imaged subduction structure clearly indicates that the coseismic rupture of the 1973 event occurred between the subducting oceanic crust and the Kuril island arc crust at 15–30 km depth. A thermally determined updip limit of the seismic rupture (100°C) corresponds to the seismically determined updip limit (15 km depth). An analysis of amplitude variations of wide‐angle reflections demonstrated a highly reflective plate interface immediately trenchward of the coseismic rupture zone (shallower than 15 km depth), while a weakly reflective interface is observed at the coseismic rupture zone. From the observed amplitude variation with offsets, a thin low‐velocity layer (4.5 km/s) is observed at the top of the highly reflective interface. This suggests the presence of fluid, which would indicate weak coupling updip of the rupture zone. We also deduced, from these observations, that a weakly reflective interface in the coseismic slip zone represents a strongly coupled zone pending the next megathrust earthquake.
Magnetic and clast fabrics as measurements of grain‐scale processes within the Death Valley shallow crustal detachment faults
Authors: Hayman Nicholas W. , Housen B. A. , Cladouhos T. T. , Livi K.
Published: May 2004

The rock product of shallow‐crustal faulting includes fine‐grained breccia and clay‐rich gouge. Many gouges and breccias have a fabric produced by distributed deformation. The orientation of fabric elements provides constraints on the kinematics of fault slip and is the structural record of intrafault strain not accommodated by planar and penetrative surfaces. However, it can be difficult to quantify the deformational fabric of fault rocks, especially the preferred orientations of fine‐grained minerals, or to uniquely determine the relationship between fabric geometry and finite strain. Here, we present the results of a fabric study of gouge and breccia sampled from low‐angle normal (detachment) faults in the Black Mountains, Death Valley, CA. We measured a preferred orientation of the long axes of the clasts inherited from the crystalline footwall of the fault and compared the shape preferred orientation to the anisotropy of magnetic susceptibility of the fault rocks. The two measurements of fabric exhibit systematic similarities and differences in orientation and anisotropy that are compatible with the large‐scale kinematics of fault slip. The dominant carriers of the magnetic susceptibility are micron‐ and sub‐micron scale iron oxides and clay minerals. Therefore even the finest grains in the fault rock were sensitive to the distributed deformation and the micro‐mechanics of particle interaction must have departed from those assumed by the passive‐marker kinematic model that best explains the fabric.
Uncertainty in estimating carbon emissions from boreal forest fires
Authors: French Nancy H. F. , Goovaerts Pierre , Kasischke Eric S.
Published: May 2004

The uncertainty in carbon emissions from fire was estimated for the boreal region of Alaska over the 50 years of recorded wildfire. Building on previous work where carbon emissions were estimated using a geographic information systems‐based model, the uncertainty attached to the different parameters of the basic equation was assessed and propagated through the equation using Monte Carlo simulation. The result is a distribution of possible values for total carbon and three carbon‐based gases (CO2, CO, and CH4) that provides a measure of the uncertainty in the output estimates. Additionally, the relative impact of each input parameter on the output uncertainty has been quantified (sensitivity analysis). Assumptions were made in building the uncertainty model regarding the shape of the distribution of each model parameter since this information is unavailable. Because of the lack of information on the precision of input parameter estimates, a range of possible spread values for the probability distributions, as defined by the coefficient of variation (CV; standard deviation/mean), was considered. Using the “best guess” values for input CVs, the resulting estimate of total annual carbon emission can be as high as 10.6 TgC or as low as 1.1 TgC, a CV of 24%. Lowering the input CVs to 5% results in an output CV of 4.2% for total carbon emissions. For the three carbon‐based gases the CV of simulated carbon distributions for the “best guess” scenario ranges from 23 to 27%. The sensitivity analysis reveals that ground‐layer fraction consumed, βg, is the most important parameter in terms of output uncertainty. The results of this work emphasize that current estimates of carbon emission from biomass burning are not well constrained because input data sets are incomplete and lack adequate error information. Furthermore, we conclude that although burn area estimates are improving, more effort is needed in quantifying fuel and consumption variables at fire sites if accurate estimates of carbon emissions from fire are to be made.
A study of ozone variability and its connection with meridional transport in the northern Pacific lower stratosphere during summer 2002
Authors: Leblanc Thierry , McDermid I. Stuart , Hauchecorne Alain
Published: June 2004

A preliminary study of the impact of the north‐central Pacific circulation in the subtropical stratosphere on ozone variability locally observed by lidar is presented. The results from the upper tropospheric and stratospheric ozone measurements of the Jet Propulsion Laboratory lidars located at Mauna Loa Observatory (MLO), Hawaii, and Table Mountain Facility (TMF), California, during summer 2002 were compared to isentropic potential vorticity (IPV) advected on 54 levels from 320 to 1500 K by the high‐resolution model MIMOSA. The correlation between ozone measured by lidar, and the origin of the 10‐day backward trajectories of the air parcels sampled, was also investigated. Near the tropopause, strong positive correlation between ozone mixing ratio and IPV was observed at both MLO and TMF lidar sites. The largest fluctuations were centered near 350 K and are associated with the meridional displacement of the tropopause by Rossby waves north or south of the observing sites. These large displacements were occasionally accompanied by Rossby wave breaking (RWB), as was identified several times during the summer in the vicinity of the Hawaiian Islands. Using IPV maps, a case study of the 13 July event is briefly presented. This event appears to be typical of breaking events previously investigated at midlatitudes, including the southward intrusion of high‐PV air originating in the high‐latitude lower stratosphere. This time the intrusion was observed to extend deep in the subtropics. Strong positive ozone anomalies were simultaneously measured by the MLO lidar. Positive correlation between ozone and the equivalent latitude averaged along the parcels' trajectories was seen up to 475 K in the stratosphere. At and above 750 K, negative correlation was calculated for both TMF and MLO. For TMF the altitude dependence of the correlation is similar to that already observed for summer and winter midlatitudes For MLO the observed negative correlation was found to be the result of opposite seasonal and interannual tendencies in ozone and equivalent latitude throughout the summer. All other correlations are associated with a higher intraseasonal variability of both ozone and the parcels' origin, as compared to their seasonal tendencies.
Wind‐borne redistribution of snow across an Antarctic ice rise
Authors: King J. C. , Anderson P. S. , Vaughan D. G. , Mann G. W. , Mobbs S. D. , Vosper S. B.
Published: June 2004

Redistribution of snow by the wind can drive spatial and temporal variations in snow accumulation that may affect the reconstruction of paleoclimate records from ice cores. In this paper we investigate how spatial variations in snow accumulation along a 13 km transect across Lyddan Ice Rise, Antarctica, are related to wind‐borne snow redistribution. Lyddan Ice Rise is an approximately two‐dimensional ridge which rises about 130 m above the surrounding ice shelves. Local slopes on its flanks never exceed 0.04. Despite this very smooth profile, there is a pronounced gradient in snow accumulation across the feature. Accumulation is highest on the ice shelf to the east (climatologically upwind) of the ice rise and decreases moving westward, with the lowest accumulation seen to the west (climatologically downwind) of the ice rise crest. Superimposed on this broad‐scale gradient are large (20–30%), localized variations in accumulation on a scale of around 1 km that appear to be associated with local variations in surface slope of less than 0.01. The broad‐scale accumulation gradient is consistent with estimates of wind‐borne redistribution of snow made using wind speed observations from three automatic weather stations. The small‐scale variability in accumulation is reproduced quite well using a snow transport model driven by surface winds obtained from an airflow model, providing that both the wind shear and static stability of the upwind flow are taken into account. We conclude that great care needs to be exercised in selecting ice core sites in order to avoid the possibility of blowing snow transport confounding climate reconstructions.
A cometary neutral gas simulator for gas dynamic sensor and mass spectrometer calibration
Authors: Graf S. , Altwegg K. , Balsiger H. , Jäckel A. , Kopp E. , Langer U. , Luithardt W. , Westermann C. , Wurz P.
Published: May 2004

The goal of the European Space Agency's Rosetta mission is a rendezvous with the Edgewood‐Kuiper Belt comet 67P/Churyumov‐Gerasimenko. After the initial encounter the spacecraft will accompany the comet for one to two years toward the Sun and throughout the perihelion passage. For the calibration of the onboard comet mass spectrometers a calibration system was built to simulate the neutral gas environment around a cometary nucleus. This facility consists of a fully automated three‐chamber ultra‐high vacuum system with a separate gas‐mixing unit and a docking section with a five‐axis table for instrument positioning and support. The gas‐mixing unit produces mixtures of gases and also gas water vapor mixtures. The gas mixtures are fed into the vacuum system by a leak valve (static mode) or through a nozzle to form a molecular beam (dynamic mode). All flight and flight spare sensors of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) have been calibrated in the static mode of the Calibration System for the Mass Spectrometer Instrument ROSINA (CASYMIR). Preliminary calibration measurements in a pressure range from 10−9 to 10−6 mbar for carbon dioxide and for noble gases from helium to xenon show very promising results.
Dominant propagating signals in sea level anomalies in the Southern Ocean
Authors: Pottier C. , Céron J.‐P. , Sudre J. , Dadou I. , Belamari S. , Garçon V.
Published: June 2004

We examine the time evolution over an 11 yr time series of the dominant modes of variability in sea level anomalies (SLA) from TOPEX/Poseidon and ERS‐1/2 in the Southern Ocean (35–60°S). We use Hayashi's classical space‐time spectral analysis and a newly developed method combining a Gabor analysis with Hayashi's method. Zonal wavenumbers 3 and 2 emerge unambiguously with null corresponding meridional wavenumber meaning that both associated modes have no meridional propagation. Their power spectrum density (PSD) is maximum within 50–55°S. The 3/0 mode displays a clear westward propagation associated with a 1.04 yr period. The 2/0 pair is characterized by a ∼4.4 yr period and exhibits a clear eastward propagation with a maximal PSD just after the 1998 El Niño peak. Zonal wavenumber‐2 mode is then probably part of the Antarctic Circumpolar Wave.
Underestimation of deep convective cloud tops by thermal imagery
Authors: Sherwood Steven C. , Chae Jung‐Hyo , Minnis Patrick , McGill Matthew
Published: June 2004

The most common method of ascertaining cloud heights from space is from thermal brightness temperatures. Deep convective clouds of high water content are expected to radiate as black bodies. Here, thermal cloud top estimates from GOES‐8 are compared with direct estimates of where the top should be sensed, based on colocated Goddard Cloud Physics Lidar (CPL) observations collected during the Cirrus Regional Study of Tropical Anvils and Florida Area Cirrus Experiment (CRYSTAL‐FACE). GOES‐8 cloud top heights are consistently ∼1 km lower than the “visible” cloud top estimates from the lidar, even though the latter take into account the finite visible opacity of the clouds and any overlying thin cirrus layers, and are often far below the position of highest detected cloud. The low bias in thermal estimates appears to get worse for the tallest clouds, perhaps by an additional kilometer, and depends little on cloud albedo. The consistency of the bias over multiple satellites suggests that cloud retrievals are affected by an unexpected radiative transfer issue.
Effective collision frequency due to ion‐acoustic instability: Theory and simulations
Authors: Hellinger Petr , Trávníček Pavel , Menietti J. Douglas
Published: May 2004

We study the ion‐acoustic instability driven by a drift between Maxwellian protons and electrons in a nonmagnetized plasma using a Vlasov simulation with the realistic proton to electron mass ratio. Simulation results for similar electron and proton temperatures are in good agreement with predictions. Namely, during the linear and saturation phases the effective collision frequency observed in the simulation is in quantitative agreement with the quasi‐linear predictions. However, previous estimates [Galeev and Sagdeev, 1984; Labelle and Treumann, 1988] give the effective collision frequency less than one tenth the simulated values. The theoretical and simulation results are in a partial agreement with the simulation work by Watt et al. [2002] who used a non‐realistic mass ratio. After the saturation, the effective collision frequency increases owing to the existence of backward‐propagating ion‐acoustic waves. These waves result from induced scattering on protons and contribute to the anomalous transport of electrons.
Air‐surface exchange of peroxyacetyl nitrate at a grassland site
Authors: Doskey Paul V. , Kotamarthi V. Rao , Fukui Yoshiko , Cook David R. , Breitbeil Fred W. , Wesely Marvin L.
Published: May 2004

Direct measurements of the dry deposition velocity of peroxyacetyl nitrate (PAN) were made during the daytime between the months of July and October above a grassland surface in northern Illinois by a modified Bowen ratio technique. Differences in the air temperature, water vapor content, and PAN concentration were measured between the heights of 3.0 m and 0.92 m. Although the measurement uncertainties were large, the cumulative data indicate a slight downward flux of PAN, with an average and standard error of 0.13 ± 0.13 cm s−1 for the dry deposition velocity. Theoretical calculations showed that thermochemical decomposition of PAN on leaf and soil surfaces heated to temperatures above the ambient air levels would contribute less than 15% of the total PAN flux at the elevations of the PAN measurements. A theoretical evaluation of the transfer of PAN through leaf stomata and the plant cuticular membrane indicated that uptake of PAN by vegetation during the daytime is controlled by transfer through the leaf stomata rather than the cuticular membrane. The stomatal resistance for PAN is greater by a factor of 1.6 than the value for O3. The mesophyll resistance for O3 is also expected to be less than the value for PAN, because O3 has more reaction sites within plant cells and reacts faster than PAN with protein thiols of the cell membranes. Measurements from other studies indicate that the dry deposition velocity for PAN above a vegetated surface during the daytime is lower by a factor of 0.5–0.3 than for O3. Our measurements of the PAN deposition velocity agree with the results of previous studies and with theoretical calculations based on the physicochemical properties of PAN and the grassland surface. These measurements imply that removal of PAN from the daytime atmospheric boundary layer by thermochemical decomposition is more rapid than dry deposition to a grassland surface.
Identification of a potent and highly efficacious, yet slowly desensitizing CB1 cannabinoid receptor agonist
Authors: Luk Terry , Jin Wenzhen , Zvonok Alexander , Lu Dai , Lin Xin‐Zhong , Chavkin Charles , Makriyannis Alexandros , Mackie Ken
Published: June 2004

The relationship of agonist efficacy to the rate of G protein‐coupled receptor signaling desensitization is controversial.

Expressing inwardly rectifying potassium channels (GIRKs) in Xenopus oocytes, we have devised a signaling assay that clearly identifies CB1 cannabinoid receptor agonists with low intrinsic efficacy.

In this assay, the synthetic CB1 agonists, AM411, AM782, AM1902, AM2233 and WIN55,212‐2 and the endogenous cannabinoid, 2‐arachidonoyl ester, were full agonists.

The synthetic CB1 agonist AM356 (methanandamide), the endogenous cannabinoids, anandamide and 2‐arachidonoyl ether, and the phytocannabinoid, Δ9THC, were partial agonists.

The rate of desensitization of CB1 was independent of agonist efficacy. WIN55,212‐2, AM782, AM1902, AM2233, and 2‐arachidonoyl glycerol ester all desensitized quickly, with desensitization rates varying from 14% min−1 to 10% min−1. AM356, AM411, anandamide, and Δ9THC all desensitized considerably slower, at a rate of 5% min−1.

Despite high potency and efficacy, AM411 desensitized as slowly as anandamide and Δ9THC.

CB1 agonist efficacy and rate of desensitization are not necessarily related.

British Journal of Pharmacology (2004) 142, 495–500. doi:10.1038/sj.bjp.0705792
Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D‐glucose transport
Authors: Naftalin Richard J , Cunningham Philip , Afzal‐Ahmed Iram
Published: June 2004

Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin‐releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2‐oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro.

The potencies of nootropic drugs in opposing scopolamine‐induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (P<0.01). Less potent nootropics, D‐levetiracetam and D‐pyroglutamate, have higher antagonist Ki's against pentobarbital inhibition of glucose transport than more potent L‐stereoisomers (P<0.001).

Piracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport.

There are similarities between amino‐acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine‐binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region.

Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin‐induced narcosis.

British Journal of Pharmacology (2004) 142, 594–608. doi:10.1038/sj.bjp.0705798
Experimental hypothyroidism modifies specific binding of A1 and A2A analogues to adenosine receptors in the rat kidney
Authors: Franco Martha , Galicia Othir , Quintana Alicia , Martínez Flavio
Published: June 2004

Binding kinetic studies with the adenosine analogues [3H]CPA (0.250–50 nM) and [3H]CGS21680 (0.1–100 nM) were performed in renal tissue from control (NL) and thyroidectomised (HTX) rats. We propose that the low renal adenosine content reported in hypothyroid rats may induce changes in the density and/or affinity of adenosine receptor, distributed in the cortex (C), outer medulla (OM), and inner medulla (IM) of the kidney.

[3H]CPA and [3H]CGS21680 binding saturation isotherms were fitted by nonlinear regression analysis and evaluated by Furchgott's method. These results revealed high (KH) and low (KL) affinity (KD) sites for both compounds. As expected, a heterogeneous pattern was observed for Bmax and KD values.

Bound [3H]CPA and [3H]CGS21680 were displaced by increasing concentrations of nonlabelled DPCPX and NECA, respectively, indicating the presence of A1 and A2A adenosine receptors distributed in the renal segments studied.

The relative intrinsic efficacy (ɛ) for [3H]CPA and [3H]CGS21680 showed extreme values (far from 1.0), 0.5 in IM NL and 2.70 in IM HTX for [3H]CGS21680.

Our results indicate that A2A adenosine receptor is predominant in IM from HTX, but A1 receptors are expressed preferentially in C in NL.

We conclude that the changes observed in number, affinity, and ɛ for the A2A receptor in IM from HTX might be responsible from alterations in medullary function, that is, incapacity for urine concentration as observed in the hypothyroid kidney.

British Journal of Pharmacology (2004) 142, 461–468. doi:10.1038/sj.bjp.0705799
The leaf extract of Ginkgo Biloba L. suppresses oxidized LDL‐stimulated fibronectin production through an antioxidant action in rat mesangial cells
Authors: Akiba Satoshi , Chiba Masahiro , Mukaida Yuki , Tamura Akira , Sato Takashi
Published: June 2004

The leaf extract of Ginkgo Biloba L. exhibits a variety of pharmacological effects through an antioxidant action. We examined the effects of the leaf extract (Ginkgolon‐24) on the production of fibronectin induced by oxidized low‐density lipoprotein (oxLDL) in rat mesangial cells.

Stimulation with oxLDL accelerated the production of fibronectin with the preceding generation of reactive oxygen species (ROS). Pretreatment with Ginkgolon‐24 inhibited the oxLDL‐induced fibronectin production as well as ROS generation.

oxLDL also elicited the activation of SP‐1, nuclear factor‐κB, and cAMP response element‐binding protein, which are transcription factors involved in the fibronectin production. Among these activated transcription factors, Ginkgolon‐24 inhibited the activation of SP‐1 only.

Furthermore, 7‐ketocholesterol, an oxidized lipid in oxLDL particles, induced the production of fibronectin and the activation of SP‐1, which were also suppressed by Ginkgolon‐24.

These results suggest that the leaf extract of Ginkgo Biloba L. inhibits the oxLDL‐induced production of fibronectin probably through inhibitory effects on ROS generation and SP‐1 activation in rat mesangial cells.

British Journal of Pharmacology (2004) 142, 419–424. doi:10.1038/sj.bjp.0705805
Identification of the active metabolite of ticlopidine from rat in vitro metabolites
Authors: Yoneda Kenji , Iwamura Ryou , Kishi Hiroko , Mizukami Yoichi , Mogami Kimiko , Kobayashi Sei
Published: June 2004

Ticlopidine is a well‐known anti‐platelet agent, but is not active by itself in vitro. We identified a metabolite with anti‐platelet activity, which was generated after incubation of 2‐oxo‐ticlopidine with phenobarbital‐induced rat liver homogenate in vitro.

An active moiety (UR‐4501) was isolated by high‐performance liquid chromatography after large‐scale preparation of metabolites.

The chemical structure of UR‐4501 was determined by a combination of liquid chromatography mass/mass spectrometry (LC/MS/MS) and nuclear magnetic resonance (NMR) analysis.

UR‐4501 produced a concentration‐dependent inhibition (3–100 μM) of ADP (10 μM)‐induced human platelet aggregation, whereas 2‐oxo‐ticlopidine (3–100 μM) did not elicit inhibitory responses.

UR‐4501 (10–100 μM) strongly inhibited ADP‐ and collagen‐induced aggregation and slightly inhibited thrombin‐induced aggregation.

The inhibition of rat washed platelet aggregation by UR‐4501 (100 μM) persisted, even after the platelets had been washed twice.

These results suggest that UR‐4501 is the molecule responsible for the in vivo activities of ticlopidine.

British Journal of Pharmacology (2004) 142, 551–557. doi:10.1038/sj.bjp.0705808
3′,4′‐Dihydroxyflavonol reduces infarct size and injury associated with myocardial ischaemia and reperfusion in sheep
Authors: Wang Sheng , Dusting Gregory J , May Clive N , Woodman Owen L
Published: June 2004

The antioxidant properties of flavonols in vivo and their potential benefits in myocardial ischaemia/reperfusion (I/R) injury have been little investigated. We evaluated the ability of a synthetic flavonol, 3′,4′‐dihydroxyflavonol (DiOHF) to scavenge superoxide in post‐I/R myocardium and to prevent myocardial I/R injury.

Anaesthetized sheep were studied in four groups (n=5–6): control, ischaemic preconditioning (IPC), vehicle and DiOHF (before reperfusion, 5 mg kg−1, i.v.). The left anterior descending coronary artery was occluded distal to the second diagonal branch for 1 h followed by 2 h of reperfusion. Infarct size, myocardial function, NADPH‐activated superoxide generation and biochemical markers of injury were measured.

DiOHF (10−8–10−4 M) incubated in vitro with post‐I/R myocardium from the vehicle group suppressed superoxide production dose‐dependently. DiOHF administered in vivo also significantly reduced superoxide generation in vitro.

DiOHF and IPC markedly reduced infarct size, which was 73±2% of the area at risk in vehicle, 50±4% in DiOHF, 75±5% in control and 44±4% in IPC. Post‐I/R segment shortening within the ischaemic zone was greater in DiOHF (2.3±0.7%; P<0.01) and IPC (1.7±0.5%; P<0.01) than those in corresponding controls (−1.7±0.4; −2.1±0.4%).

DiOHF and IPC improved coronary blood flow to the ischaemic area and preserved higher levels of nitric oxide metabolites in the venous outflow from the ischaemic zone.

DiOHF attenuated superoxide production in post‐I/R myocardium, and significantly reduced infarct size and injury following I/R in anaesthetized sheep. The extent of protection by DiOHF is comparable to that afforded by IPC. Thus, DiOHF has clinical potential for improving recovery from acute myocardial infarction and other ischaemic syndromes.

British Journal of Pharmacology (2004) 142, 443–452. doi:10.1038/sj.bjp.0705815
Long‐Term Outcome of Patients Who Received Implantable Cardioverter Defibrillators for Stable Ventricular Tachycardia
Authors: GLIKSON MICHAEL , LIPCHENCA IGOR , VISKIN SAMI , BALLMAN KARLA V. , TRUSTY JANE M. , GUREVITZ OSNAT T. , LURIA DAVID M. , ELDAR MICHAEL , HAMMILL STEPHEN C. , FRIEDMAN PAUL A.
Published: May 2004

Introduction: Evidence is inconclusive concerning the role of implantable cardioverter defibrillators (ICDs) to treat patients with hemodynamically stable ventricular tachycardia (VT). The goal of this study was to estimate future risk of unstable ventricular arrhythmias in patients who received ICDs for stable VT.

Methods and Results: We reviewed complete ICD follow‐up data from 82 patients (age 66.1 ± 11.3 years; left ventricular ejection fraction 32.3%± 11.2%; mean ± SD) who received ICDs for stable VT. During the follow‐up period of 23.6 ± 21.5 months (mean ± SD), 15 patients (18%) died, and 10 (12%) developed unstable ventricular arrhythmia, 8 of whom had the unstable arrhythmia as the first arrhythmia after ICD placement. Estimated 2‐ and 4‐year survival in the whole group was 80% and 74%, respectively. Estimated 2‐ and 4‐year probability of any VT and unstable VT was 67% and 77% and 11% and 25%, respectively. There were no differences in age, ejection fraction, sex, underlying heart disease, cycle length, symptoms, baseline electrophysiologic study results, or QRS characteristics of qualifying VT between patients who developed unstable ventricular arrhythmia and patients who did not. Twenty‐nine patients (35%) had at least one inappropriate shock, and 11 (13%) underwent further surgery for ICD‐related complications.

Conclusion: Patients who present with hemodynamically stable VT are at risk for subsequent unstable VT. ICD treatment offers potential salvage of patients with stable VT who subsequently develop unstable VT/ventricular fibrillation, although complications and inappropriate shocks are considerable. No predictors could be found for high and low risk for unstable arrhythmias. These findings support ICD treatment for stable VT survivors. (J Cardiovasc Electrophysiol, Vol. 15, pp. 658‐664, June 2004)
Markers of Myocardial Damage, Tissue Healing, and Inflammation After Radiofrequency Catheter Ablation of Atrial Tachyarrhythmias
Authors: BRUECKMANN MARTINA , WOLPERT CHRISTIAN , BERTSCH THOMAS , SUESELBECK TIM , LIEBETRAU CLAUDIA , KADEN JENS J. , HUHLE GUENTER , NEUMAIER MICHAEL , BORGGREFE MARTIN , HAASE KARL K.
Published: May 2004

Introduction: Radiofrequency ablation produces a localized endomyocardial necrosis that may result in release of biochemical markers reflecting myocardial cell damage, inflammation, and tissue reparation. The aim of this study was to determine the extent of rise and time course of markers of inflammation and tissue reparation in patients undergoing radiofrequency catheter ablation.

Methods and Results: Serial blood samples were taken from patients with AV nodal reentrant tachycardia (n = 5), Wolff‐Parkinson‐White syndrome (n = 3), and atrial flutter (n = 5) undergoing radiofrequency ablation. Blood was taken before ablation (day 0, baseline) and at day 1 and day 120 after ablation. The proinflammatory marker interleukin‐6 (IL‐6), troponin I (TNI), and myoglobin, as well as matrix metalloproteinase‐9 (MMP‐9), a marker for myocardial healing, were measured by enzyme‐linked immunosorbent assay. Levels of IL‐6, TNI, myoglobin, and MMP‐9 were significantly elevated on day 1 after ablation compared to baseline levels. Seven of the 13 patients had troponin levels greater than the threshold of significant myocardial damage (>0.1 ng/mL) on day 1. Plasma levels of MMP‐9 were still elevated on day 120 compared to values before ablation (P = 0.021).

Conclusion: Markers of inflammation, wound healing, and myocardial damage are increased in patients who undergo radiofrequency ablation. Levels of MMP‐9, a marker for myocardial healing and repair, are still elevated 120 days after the procedure, suggesting that radiofrequency ablation induces tissue damage leading to a long‐term process of reparation. (J Cardiovasc Electrophysiol, Vol. 15, pp. 686‐691, June 2004)
On the Atrial Response to Focal Discharges in Man
Authors: RAMANNA HEMANTH , BAKKER JACQUES M.T. DE , ELVAN ARIF , RICHARD N.W. HAUER M.D.
Published: May 2004

Introduction: Triggers and vulnerability are key factors for the occurrence of atrial fibrillation (AF). The aim of this study was to assess spatial dispersion of atrial refractoriness and vulnerability in response to both focal discharges as well as programmed electrical stimulation in patients undergoing ablation of atrial arrhythmogenic foci.

Methods and Results: Twenty‐nine patients were studied, and 12 right atrial unipolar electrograms were recorded. Inducibility of AF was assessed by a pacing protocol that started with one extrastimulus, followed by more aggressive pacing until AF was obtained. Mean fibrillatory intervals were used to assess the local refractoriness of each recording site. Spatial dispersion of refractoriness was calculated as the coefficient of dispersion (CD value: standard deviation of the mean of all local mean fibrillatory intervals as a percentage of the overall mean fibrillatory interval). Based on our previous study, a CD value ≤ 3.0 was defined as normal, whereas a CD value >3.0 was considered enhanced spatial dispersion of refractoriness. Fifteen of 29 patients had normal dispersion of refractoriness (mean CD value 1.65 ± 0.43), and AF was inducible with burst pacing only. These patients had focal discharges causing rapid atrial tachycardia with a focal activation pattern. Activation mapping of focal activity was possible in 14 of 15 patients. Focal triggering of AF occurred in only 1 of 15 patients. Fourteen of 29 patients had enhanced dispersion (mean CD value 4.2 ± 0.72). AF was inducible with a single extrastimulus in 11 of 14 patients (P < 0.001). Focal triggering of AF occurred in all 14 patients.

Conclusion: Spatial dispersion of atrial refractoriness determines whether focal atrial discharges trigger AF with disorganized activity or, alternatively, only rapid atrial tachycardia. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1‐8, June 2004)
Transmural Distribution of Connexins in Rodent Hearts
Authors: YAMADA KATHRYN A. , KANTER EVELYN M. , GREEN KAREN G. , SAFFITZ JEFFREY E.
Published: May 2004

Introduction: Electrophysiologic heterogeneity across the ventricular wall is a result of differential transmural expression of various ion channel proteins that underlie the different action potential waveforms observed in epicardial, midmyocardial, and endocardial regions. Cardiac connexins mediate cell‐to‐cell communication, are critical for normal impulse propagation, and play a role in electrophysiologic remodeling in disease states. However, little is known about the transmural distribution of cardiac gap junction proteins.

Methods and Results: Connexin expression in epicardium, midmyocardium, and endocardium was assessed immunohistochemically in mouse and rat hearts. The total connexin protein content within different ventricular regions was measured by immunoblotting. Connexin43 is twice as abundant in midmyocardium and endocardium compared with epicardium in the mouse but not in the rat. Connexin45 is expressed equally across the left ventricular wall.

Conclusion: Epicardial myocytes express significantly less Cx43 and therefore may be less well coupled than midmyocardial and endocardial myocytes. A transmural gradient of connexin43 expression across the left ventricular free wall likely results in differences in the stoichiometry of connexins expressed in different regions of the heart. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1‐6, June 2004)