bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrieval of aerosol optical thickness and size distribution from the CIMEL Sun photometer over Inhaca Island, Mozambique
Authors: Queface Antonio J. , Piketh Stuart J. , Annegarn Harold J. , Holben Brent N. , Uthui Rogerio J.
Published: July 2003

Characterization of aerosol optical properties over southern Africa is needed to better understand the impact of aerosols on regional climate change. CIMEL Sun photometer measurements of aerosol optical thickness over Inhaca Island, Mozambique, between April and November 2000 are analyzed. Comparisons with two other sites, Mongu, Zambia, and Bethlehem, South Africa, are made. The aerosol optical thickness observed at Inhaca Island indicates high turbidity. In ∼50% of the measurements, aerosol optical thickness values are above 0.2, with an overall mean of 0.26 ± 0.19. The Angström exponent parameter has a wide range from 0.2 to 2, with a modal value of 1.6. This indicates a wide range in particle sizes and the dominance of fine mode aerosols at this site. Data from all three sites reveal seasonal variability, with a significant increase in aerosol content between August and October. This suggests a strong contribution of biomass burning to the atmospheric aerosols content during this time of year, which corresponds to the period of maximum burning in southern Africa. A north to south gradient in aerosol optical thickness is confirmed. The highest aerosol content is observed over Mongu, while Bethlehem has the lowest. The retrieved aerosol volume size distribution over Inhaca Island demonstrates that at high levels of aerosol optical thickness, accumulation mode aerosols dominate. In contrast, coarse mode aerosols dominate when aerosol optical thickness is very low. It is noted that there is a tendency for decreasing particle size as aerosol optical thickness increases, with the peak in distribution of the accumulation mode volume radius decreasing from 0.19 μm at τa = 0.42 to ∼0.14 μm at τa = 1.12.
Interannual covariability in Northern Hemisphere air temperatures and greenness associated with El Niño‐Southern Oscillation and the Arctic Oscillation
Authors: Buermann Wolfgang , Anderson Bruce , Tucker Compton J. , Dickinson Robert E. , Lucht Wolfgang , Potter Christopher S. , Myneni Ranga B.
Published: July 2003

In this paper, we estimate the year‐to‐year variations in northern vegetation greenness as they relate to the dominant modes of climate variability. In particular, we analyze spatial data of Northern Hemisphere satellite‐sensed vegetation greenness, surface temperature, precipitation, and upper air data for the 1982–1998 period to isolate well correlated modes of variability between temperature and greenness and to assess their relationship to large‐scale circulation anomalies. It is found that during spring, large‐scale modes of interannual vegetation variability are strongly correlated with spatiotemporal modes of variability in the overlying temperature field. In addition, the results indicate that the two predominant hemispheric‐scale modes of covariability are related to teleconnections associated with the El Niño‐Southern Oscillation (ENSO) and the Arctic Oscillation (AO). The warm event ENSO signal is manifested as warmer and greener conditions in North America, Far East Asia, and to some extent central Europe, while the features of the positive phase AO signal include enhanced warm and green conditions over large regions in Europe and Asian Russia, with opposite anomalies in the eastern half of North America. Whether observed trends in vegetation activity over the past 20 years are also related to systematic changes in these two modes of variability is still unclear.
Ionospheric and dynamical characteristics of the mesosphere‐lower thermosphere region over Platteville (40°N, 105°W) and comparisons with the region over Saskatoon (52°N, 107°W)
Authors: Manson A. H. , Meek C. E. , Avery S. K. , Thorsen D.
Published: July 2003

The newly installed medium frequency radar (MFR) at Platteville provides unique opportunities to assess latitudinal effects in both the ionosphere and mesosphere‐lower thermosphere (MLT) by comparisons with the long‐established MFR at Saskatoon. The influence of the D region “winter anomaly” is evident in both ionospheres, and descending “sporadic layers” (110–90 km) are identified, especially at 40°N, for the first time for MF radar systems. Preliminary comparisons with the wind measurements are made, and the processes are identified as complex. Contour plots of mean winds, tides (12‐ and 24‐hour), and planetary waves (PW) (2‐ and 16‐day) demonstrate significant trends over 12° of latitude (1100 km). The 24‐hour tide dominates at 40°N, the 12‐hour tide dominates at 52°N, and PW structures demonstrate spatial and temporal intermittency. The two radars are now part of a new network, Canada U.S. Japan Opportunity (CUJO), stretching from 81°W to 141°E.
Interannual variations of monthly and seasonal normalized difference vegetation index (NDVI) in China from 1982 to 1999
Authors: Piao Shilong , Fang Jingyun , Zhou Liming , Guo Qinghua , Henderson Mark , Ji Wei , Li Yan , Tao Shu
Published: July 2003

In this paper, we analyzed interannual variations of normalized difference vegetation index (NDVI) and their relationships with climatic variables (temperature and precipitation) and human activity in China between 1982 and 1999. Monthly and seasonal NDVI increased significantly at both the country and biome scales over the study period. NDVI shows the largest increase (14.4% during the 18 years and a trend of 0.0018 yr−1) over 85.9% of the total study area in spring and the smallest increase (5.2% with a trend of 0.0012 yr−1) over 72.2% of the area in summer. The NDVI trends show a marked heterogeneity corresponding to regional and seasonal variations in climates. There is about a 3‐month lag for the period between the maximum trend in temperature (February) and that in NDVI (April or May) at the country and biome scales. Human activity (urbanization and agricultural practices) also played an important role in influencing the NDVI trends over some regions. Rapid urbanization resulted in a sharp decrease in NDVI in the Yangtze River and Pearl River deltas, while irrigation and fertilization may have contributed to the increased NDVI in the North China plain.
Influence of seasonality, canopy light extinction, and terrain on potential isoprenoid emission from a Mediterranean‐type ecosystem in France
Authors: Schaab Gertrud , Steinbrecher Rainer , Lacaze Bernard
Published: July 2003

Sensitivity studies for simulations of yearly cycles and terrain effects are presented for the St.‐Martin‐de‐Londres region (southern France). Potential isoprenoid emissions are simulated using the Solar Radiation Model (SORAM), spatial effects of complex terrain, photosynthetically active radiation, and surface temperature. SORAM is embedded in a geographic information system (GIS) environment and considers a digital elevation model (DEM) of the model domain. Compared to the maximum case (i.e., no variation in emission factors and leaf area index (LAI)), seasonality in LAI for that Mediterranean‐type landscape mainly covered by evergreen plant species resulted in an annual amount of 3.5% less for total isoprenoids. By including the intra‐annual change in emission factors an additional 12.5% reduction was derived for the area. When the SORAM module that accounts for light extinction within the canopy was switched off, modeled yearly amount in emission increased by 48%. Complex terrain effects showed only a weak influence for the rather moderate terrain of the modeling domain (mean difference of approximately −2.5% in daily sums). However, sensitivity studies based on the DEM exaggerated by a factor of 2 (resulting in differences of −11.7% for the light‐ and temperature‐dependent isoprenoids) revealed that in the case of pronounced relief or if highly resolved results are necessary, the orography should be considered when modeling the driving parameters of light and temperature.
Modeling the effects of three‐dimensional vegetation structure on surface radiation and energy balance in boreal forests
Authors: Yang Rongqian , Friedl Mark A.
Published: July 2003

Radiation and turbulent energy exchange between vegetation and the atmosphere is an important component of land surface‐atmosphere interaction. Vegetation properties strongly influence this exchange. Commonly, two‐stream models are used to compute net absorbed radiation and the partitioning of absorbed radiation between the vegetation canopy and substrate. Also, the roughness lengths for momentum and heat are often parameterized as simple functions of vegetation height. In this paper, we examine the influence of vegetation three‐dimensional (3‐D) structure on land surface radiation and energy balance over nonuniform forest canopies. To do this, parameterizations that account for the effects of canopy 3‐D structure on radiation and turbulent energy exchange were implemented in the National Center for Atmospheric Research (NCAR) land surface model (LSM) version 1.0. The NCAR LSM then was run offline for a time period encompassing both wet and dry soil moisture conditions using forcing data from the Boreal Ecosystem‐Atmosphere Study (BOREAS). Radiation and energy balance within the vegetation canopy and at the soil surface were examined at diurnal timescales. Results show that the 3‐D parameterizations increased net radiation absorbed by the soil surface and that this additional available energy was primarily dissipated through ground evaporation when soil moisture was not limiting. When the soil was dry, the available energy at the soil surface was mostly converted to sensible heat with relatively little change in the ground heat flux. In addition, modeled sensible heat from the vegetation canopy decreased, and relatively small changes in modeled canopy transpiration were observed. Comparisons of modeled heat fluxes using the 3‐D parameterizations against observations show improvement over the original treatment included in the NCAR LSM, suggesting that careful treatment of vegetation properties is important to accurate modeling of flux quantities above and underneath the canopy in soil‐vegetation‐atmosphere‐transfer (SVAT) models.
Operational carbon monoxide retrieval algorithm and selected results for the MOPITT instrument
Authors: Deeter M. N. , Emmons L. K. , Francis G. L. , Edwards D. P. , Gille J. C. , Warner J. X. , Khattatov B. , Ziskin D. , Lamarque J.‐F. , Ho S.‐P. , Yudin V. , Attié J.‐L. , Packman D. , Chen J. , Mao D. , Drummond James R.
Published: July 2003

Measurements of Pollution in the Troposphere (MOPITT) is a new remote sensing instrument aboard the Earth Observing System (EOS) “Terra” satellite which exploits gas correlation radiometry principles to quantify tropospheric concentrations of carbon monoxide (CO) and methane (CH4). The MOPITT CO retrieval algorithm employs a nonlinear optimal estimation method to iteratively solve for the CO profile which is statistically most consistent with both the satellite‐measured radiances and a priori information. The algorithm's theoretical basis is described in terms of the observed radiances and their weighting functions, the a priori information, and the retrieval averaging kernels. Examples of actual CO retrievals over scenes with contrasting pollution conditions are demonstrated, and interpreted in the context of the retrieval averaging kernels and a priori.
A parameterization of cirrus cloud formation: Heterogeneous freezing
Authors: Kärcher B. , Lohmann U.
Published: July 2003

A physically based parameterization of cirrus cloud formation by heterogeneous freezing is developed along with a novel method to compute associated nucleation rates. The analysis is restricted to immersion freezing, possibly the dominant pathway for heterogeneous cirrus formation under cold (<235 K) conditions. The size of ice nuclei (IN) immersed in a liquid particle does not significantly affect the heterogeneous freezing threshold (the saturation ratio over ice where ice formation is initiated) of the mixed particle. If perfect IN were present at cirrus altitudes, almost all of them would freeze near ice saturation, even in slow updrafts. If only one type of less potent IN with freezing thresholds >1.3–1.4 triggers cirrus formation, cloud properties are not very susceptible to changes of IN properties, as in the case of homogeneous freezing. In contrast, much stronger indirect aerosol effects on cirrus clouds are possible if at least two types of IN with distinct freezing thresholds compete during the freezing process, most likely leading to a suppression of ice crystal concentrations.
A model for long‐term climatic effects of impacts
Authors: Luder T. , Benz W. , Stocker T. F.
Published: July 2003

We simulated climatic changes following the impacts of asteroids of different sizes on the present surface of Earth. These changes are assumed to be due to the variations of the radiation energy budget as determined by the amount of dust globally distributed in the atmosphere following the impact. A dust evolution model is used to determine the dust particle size spectra as a function of time and atmospheric altitude. We simulate radiation transfer through the dust layer using a multiple scattering calculation scheme and couple the radiative fluxes to an ocean circulation model in order to determine climatic changes and deviations over 2000 years following the impact. Resulting drops in sea surface temperatures are of the order of several degrees at the equator and decrease toward the poles, which is deduced from the increasing importance of infrared insulation of the dust cover at high latitudes. While gravitational settling reduces the atmospheric amount of dust significantly within 6 months, temperature changes remain present for roughly 1 year irrespective of impactor size. Below 1000 m ocean depth, these changes are small, and we do not observe significant modifications in the structure of the ocean circulation pattern. For bodies smaller than 3 km in diameter, climatic effects increase with impactor size. Beyond this threshold, there is enough dust in the atmosphere to block almost completely solar radiation; thus additional dust does not enhance climatic deviations anymore. In fact, owing to interaction in the infrared, we even observe smaller effects by going from a 5 km impactor to larger diameters.
A universal bias in inorganic rainwater chemical composition data
Authors: Ayers Gregory P. , Gillett Robert W. , Selleck Paul W.
Published: July 2003

In the late 1970s, it was recognised that organic acids contributed to the acidity and ionic content of rainwater, but that these acids had not been detected because they were consumed biologically in the period between rainwater collection and subsequent laboratory analysis. Discussion of consequences for measured rainwater composition has been limited to assessment of pH gain that attends organic acid loss. We show that biological effects on rainwater ionic composition are not restricted to pH alone. Ammonium, potassium, nitrate, sulfate, methanesulfonate, and phosphate ions are also removed biologically, but remain in the rainwater in biomass, implying that most previous rainwater composition studies based on ionic analyses will have systematically underestimated nutrient deposition.
Apennines subduction‐related subsidence of Venice (Italy)
Authors: Carminati Eugenio , Doglioni Carlo , Scrocca Davide
Published: July 2003

The foreland regional monocline related to the northern Apennines subduction can be followed from the Po Basin to the Friuli region, Italy, at least 240 km north‐eastward. In seismic reflection profiles of the Po Basin and of the northern Adriatic Sea, the dip of the regional monocline gradually decreases from about 22° to close to 0°. Pleistocene sediments onlap and pinchout to the northeast. Venice is located on a segment of the active monocline dipping about 1.8° to the southwest. In sediments around the Venice area, the 1.43 Ma limit is in the 960–1500 m depth range, indicating a long term subsidence rate of about 0.7–1.0 mm/yr. Therefore a significant part of the natural component of the town subsidence is related to the north‐eastward retreat of the Adriatic subduction. The subduction related downflexure affects the whole of the Po Plain basin and part of the Southern Alps, where it opposes to the general uplift related to orogenesis.
Focused magma supply at the intersection of the Cobb hotspot and the Juan de Fuca ridge
Authors: West Michael , Menke William , Tolstoy Maya
Published: July 2003

We examine the interplay between the Cobb hotspot and the Juan de Fuca ridge by mapping the base of the crust at their intersection near Axial Volcano. PmP traveltimes from an extensive active source seismic experiment are used in conjunction with prior crustal tomography to map crustal thickness. A cross‐section along the ridge axis consists of two distinct trends. In addition to 1–2 km of excess crust, inferred from gravity along a 100 km section of the central ridge, we find a narrow 20–40 km diameter root extending to 11 km directly beneath the volcano. Focused magma flux from the Cobb hotspot (0.3–0.8 m3/s) is inferred to be the cause of both the narrow root, and the large magma reservoir, at Axial. The rapid return to thinner crust, away from the intersection, marks a transition back to ridge‐dominated magmatism.
Vertical winds in the central polar cap
Authors: Guo W. , McEwen D. J.
Published: July 2003

Upward vertical winds are observed in the polar cap F‐region over Eureka (80°N) during and following sustained polar auroras. This suggests that heating due to particle energy deposition in the F‐region is sufficient to generate upward flow. At such times there is a positive divergence in the horizontal winds, indicating that the upward flow is also outward over a >1000 km diameter across the central polar cap. The vertical winds, averaged over a 5‐winter period, also have a positive correlation with the horizontal divergences indicating the flow is generally large scale. Downward winds are seen to similarly correspond with negative divergences, and negative IMF Bz, suggesting they may be linked with activity at auroral latitudes. Vertical winds observed over Eureka at other times, appear to be oscillatory with 12‐hr and higher harmonic periods suggesting tidal activity. This preliminary conclusion will be tested by examining further winds and aeronomic data.
New evidence for enhanced ocean primary production triggered by tropical cyclone
Authors: Lin I. , Liu W. Timothy , Wu Chun‐Chieh , Wong George T. F. , Hu Chuanmin , Chen Zhiqiang , Liang Wen‐Der , Yang Yih , Liu Kon‐Kee
Published: July 2003

New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long‐speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai‐Tak passed over the South China Sea (SCS). During its short 3‐day stay, Kai‐Tak triggered an average 30‐fold increase in surface chlorophyll‐a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2–4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long‐neglected contribution of tropical cyclones to SCS's annual new production may be as much as 20–30%.
Electron density in the cusp ionosphere: increase or depletion?
Authors: Pitout Frédéric , Blelly Pierre‐Louis
Published: July 2003

Radar observations indicate that the electron density may decrease significantly in the cusp ionosphere, despite the intense precipitation of low‐energy electrons originating from the magnetosheath. We have modeled the ionospheric footprints of the cusp and mantle regions, and we focus on the two rival processes acting pro and con the electron density build‐up in those regions of intense precipitation, which also happened to be regions of strong electric field. On one hand, the precipitation provides the ionosphere with electrons; on the other hand, the strong electric field heats up the ion population, stimulating the production of NO+. A fraction of the NO+ produced then feeds the electron‐consuming chemical reaction NO+ + e− → NO in the F1‐region, although this reaction is not favored in presence of a high electron temperature. We investigate various combinations of E‐field and initial electron densities. Our simulations clearly show that the overall result depends on the origin of the flux tube, which eventually opens in the cusp region. We interpret our results in terms of seasonal effects, IMF‐By and MLT dependence.
Properties of jet engine combustion particles during the PartEmis experiment: Microphysics and Chemistry
Authors: Petzold A. , Stein C. , Nyeki S. , Gysel M. , Weingartner E. , Baltensperger U. , Giebl H. , Hitzenberger R. , Döpelheuer A. , Vrchoticky S. , Puxbaum H. , Johnson M. , Hurley C. D. , Marsh R. , Wilson C. W.
Published: July 2003

The particles emitted from an aircraft engine combustor were investigated in the European project PartEmis. Measured aerosol properties were mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, and cloud condensation nuclei (CCN) activation potential. The combustor operation conditions corresponded to modern and older engine gas path temperatures at cruise altitude, with fuel sulphur contents (FSC) of 50, 410, and 1270 μg g−1. Operation conditions and FSC showed only a weak influence on the microphysical aerosol properties, except for hygroscopic and CCN properties. Particles of size D ≥ 30 nm were almost entirely internally mixed. Particles of sizes D < 20 nm showed a considerable volume fraction of compounds that volatilise at 390 K (10–15%) and 573 K (4–10%), while respective fractions decreased to <5% for particles of size D ≥ 50 nm.
On the invariance of the first EOF of North Atlantic Sea Level Pressure to temporal filtering
Authors: da Costa E. D.
Published: July 2003

This article examines the frequency‐dependence of the shape of the first empirical orthogonal function (EOF) of sea level pressure (SLP) over the North Atlantic region for time‐scales in the range 8 months–45 years. It evidences that the time‐sacle chosen for conducting the EOF analyses had no incidence on the main features of the first EOF of North Atlantic SLP.
Attribution of regional‐scale temperature changes to anthropogenic and natural causes
Authors: Stott Peter A.
Published: July 2003

The causes of twentieth century temperature change in six separate land areas of the Earth have been determined by carrying out a series of optimal detection analyses. The warming effects of increasing greenhouse gas concentrations have been detected in all the regions examined, including North America and Europe. In most regions, cooling from sulfate aerosols counteracts some of the greenhouse warming, and there is some evidence for reduced net aerosol cooling in Asia, possibly as a result of warming from black carbon.
The role of snow cover in the warming of arctic permafrost
Authors: Stieglitz Marc , Déry S. J. , Romanovsky V. E. , Osterkamp T. E.
Published: July 2003

Air temperatures at high latitudes are expected to rise significantly as anthropogenic carbon builds up in the atmosphere. There is concern that warming of the ground in permafrost regions will result in additional release of carbon to the atmosphere. Recent emphasis has thus been on predicting the magnitude and spatial distribution of future warming at high latitudes. Modeling results show that changes in below ground temperatures can be influenced as much by temporal variations of snow cover as by changes in the near‐surface air temperature. The recent (1983–1998) changes in permafrost temperatures on the North Slope of Alaska are consistent with decadal scale variability in snow cover. The implication of these results is that a better understanding of how winter precipitation patterns at high latitudes will change over the coming decades is needed to comprehend evolving permafrost temperatures.
Summer synoptic‐scale waves over West Africa observed by TRMM
Authors: Gu Guojun , Adler Robert F. , Huffman George J. , Curtis Scott
Published: July 2003

A 5‐year daily rainfall dataset (3B42) from TRMM is used to investigate the activity and properties of westward‐propagating synoptic‐scale waves [i.e., African easterly waves (AEW)] over tropical West Africa. Evident wave signals appearing in wavenumber‐frequency space show their modulations on the surface rainfall pattern during the boreal summer. Interannual variability exists in both their intensity and spectral properties, i.e., dominant frequency and wavenumber ranges. These variabilities can be ascribed in part to year‐to‐year variations of their embedded large‐scale environment, especially the mid‐tropospheric African easterly jet (AEJ). Generally, a stronger (weaker) AEJ indicates more (less) instability energy, yielding a stronger (weaker) wave activity season. Both seasonal mean rainfall and AEWs were weak in 2001 but not in 1999. Consequently, there may exist a nonlinear relationship between the AEJ, AEWs and mean rainfall. To fully understand interannual variability of synoptic‐scale waves over tropical West Africa, including the variability in the waves' preferred frequencies and wavenumbers, it is necessary to examine possible intra‐seasonal variations in both wave activity and large‐scale fields, in addition to their structure, propagation, and associated convection.
Reactive dissolution instability driven by chemical diffusion with applications to harzburgite reactive dissolution
Authors: Liang Yan , Guo Yan
Published: July 2003

The morphological stability of a mineralogically sharp and planar dissolution front separating rock A from rock B during reactive dissolution in a multicomponent system was examined using a linear stability analysis. In the absence of melt flow, the underlining cause for the instability is chemical diffusion in the melt. The destabilizing chemical diffusion gives rise to a new class of morphological instability in which the maximum growth rate of the perturbation corresponds to the minimum wavelength of the porous system that is on the order of a few grain sizes. On the geological outcrop scale a chemical diffusion induced unstable dissolution front separating two rock units would appear diffuse. The diffuse boundaries between the harzburgite and dunite observed in ophiolites may be a result of such dissolution instability. When chemical diffusion is stabilizing the wavelength of the instability is larger and sharp lithological boundary can be preserved.
Limitations of ground‐based solar irradiance estimates due to atmospheric variations
Authors: Wen Guoyong , Cahalan Robert F. , Holben Brent N.
Published: July 2003

The uncertainty in ground‐based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley plot technique are proportional to the standard deviation of aerosol optical thickness (approximately ±13σ(δτ)). The estimates of spectral solar irradiance in two Cimel Sun photometer channels at 340 and 380 nm from the Mauna Loa site of the Aerosol Robotic Network are compared with satellite observations from the Solar Stellar Irradiance Comparison Experiment (SOLSTICE) on the Upper Atmospheric Research Satellite for almost 2 years of data. The true solar variations related to the 27‐day solar rotation cycle observed from SOLSTICE are ∼0.15% at the two Sun photometer channels. The variability in ground‐based estimates is statistically 1 order of magnitude larger. Even though ∼30% of these estimates from all Level 2.0 Cimel data fall within the 0.4–0.5% variation level, ground‐based estimates are not able to capture the 27‐day solar variation observed from SOLSTICE.
Soluble inflammatory markers in coronary sinus and peripheral blood of heart transplant recipients
Authors: Hsu Ron‐Bin , Tsay Yeou‐Guang , Lee Chii‐Ming , Chen Robert J , Wang Shoei‐Shen , Chu Shu‐Hsun
Published: July 2003

Abstract: Cardiac allograft rejection is a focal inflammation and soluble markers are released into coronary sinus (CS). We investigated whether plasma‐soluble markers in CS is better to predict the clinical status of transplant recipients than in peripheral blood (PB). Between February 1998 and January 2001, 51 patients admitted for endomyocardial biopsy were included. The clinical events of the transplant recipient were recorded as: early post‐transplant, long‐term uneventful status, infection, acute rejection and transplant coronary artery disease. The plasma levels of interleukin‐2 (IL‐2), tumor necrosis factor‐α (TNF‐α), ICAM‐1, P‐selectin, high‐sensitive C‐reactive protein (CRP) and troponin‐I of CS and PB were determined. There were 71 blood samples. In patients within 1 month after heart transplant, there was a higher level of P‐selectin, ICAM‐1, CRP and troponin‐I in CS and PB. In patients with infection, there was a higher level of all soluble markers except IL‐2 in CS and PB. Patients with a long‐term uneventful status had a lower level of CRP in PB but not in CS. Patients with acute rejection had a higher level of IL‐2 in PB but not in CS. Patients with transplant coronary artery disease had a higher level of TNF‐α in PB but not in CS. Soluble markers in CS failed to predict the occurrence of acute or chronic rejections.
Idiopathic interstitial pneumonia following stem cell transplantation
Authors: Yamaguchi Nobuko , Takatsuka Hiroyuki , Wakae Takeshi , Okada Masaya , Fujimori Yoshihiro , Okamoto Takahiro , Kakishita Eizo , Hara Hiroshi
Published: July 2003

Abstract:  Idiopathic interstitial pneumonia (IIP) can occur after stem cell transplantation, but the aetiology is unknown. Based on the association between angiitis syndrome and Helicobacter pylori infection, we identified possible risk factors common to these two conditions. Among 83 patients who underwent stem cell transplantation, four developed IIP. We elucidated various parameters and clinical features in four patients with IIP and 79 patients without, after allogeneic stem cell transplantation. In all four patients, (1) the conditioning regimen induced total body irradiation, (2) serological reactivation of cytomegalovirus and/or human herpesvirus‐6 preceded the onset of IIP, (3) their human leucocyte antigen types were among those suspected to increase susceptibility to angiitis syndrome, (4) serum anti‐H. pylori antibody was positive before conditioning and remained positive throughout the post‐transplantation course, (5) inflammatory cytokines (interleukin‐6, 8 and 12) were increased during the period of leucocyte recovery after transplantation and (6) the levels of intercellular adhesion molecule‐1, thrombomodulin and plasminogen activator inhibitor‐1 were increased at the onset of IIP. These findings suggest the possibility that angiitis syndrome and H. pylori infection are involved in the pathogenesis of post‐transplantation IIP.
Risk factors for acute rejection in living donor liver transplantation
Authors: Sugawara Yasuhiko , Makuuchi Masatoshi , Kaneko Junichi , Saiura Akio , Imamura Hiroshi , Kokudo Norihiro
Published: July 2003

Abstract:  The influence of human leukocyte antigen (HLA) compatibility and lymphocytotoxic crossmatch on acute rejection in living donor liver transplantation (LDLT) has not been well examined. We analyzed 100 consecutive adult LDLT cases. The patient and graft survival rates and post‐operative complications were assessed. The relation between the incidence of acute rejection and some clinical factors including HLA and lymphocytotoxic matching was also examined. Patients with HLA DR zero mismatching (p = 0.02) or negative T‐lymphocytotoxic crossmatch (p = 0.04) had a significantly lower chance of rejection within 6 wk after LDLT. However the results had no influence on the patient survival. Our results demonstrate that in LDLT, a graft from an HLA‐DR zero mismatching or negative T‐lymphocytotoxic crossmatch might be advantageous because of the decreased probability of early acute rejection.
Management of renal allografts with multiple renal arteries resulting from laparoscopic living donor nephrectomy
Authors: Oh Henry K , Hawasli Abdelkader , Cousins Geoffrey
Published: July 2003

Abstract:  Laparoscopic living donor nephrectomy (LLDN) has become an accepted procedure in many transplant centers. The placement of laparoscopic vascular staples can result in multiple short, small‐caliber renal arteries that the recipient surgeon must deal with to restore perfusion to all parts of the kidney. The incidence of multiple renal arteries resulting from LLDN, surgical management of multiple renal arteries, and the short‐ and long‐term graft functions were studied in 73 consecutive kidney recipients at a single center. Various techniques used for reconstruction are described, including the use of recipient internal iliac artery for the extension and reconstruction of small‐caliber, short renal vessels. Single‐artery allografts were compared with those with multiple arteries, with length of renal artery, warm ischemia time, hospital length of stay, operating time, creatinine levels, and 1 yr survival rates not found to be significantly different. The presence of multiple renal arteries should not exclude the possibility of using the left kidney for LLDN.
Intramucosal pH monitoring during liver transplantation
Authors: Mándli Tamás , Gondos Tibor
Published: July 2003

Abstract: Purpose: To apply tonometry as a quick estimation of the early liver graft function.

Patients and methods: Forty‐five liver‐transplanted patients were examined. Data were collected prospectively and analysed retrospectively. According to the early graft function, patients were classified into two groups: in group 1 (n = 28) adequate graft function, in group 2 (n = 17) deteriorated graft function was detected in the early post‐operative period. Complete conventional and volumetric haemodynamic monitoring and intramucosal pH (pHi), regional CO2 tension (PrCO2) measurements were performed during surgery and until the 36 hours post‐operatively.

Results: In group 2 the packed blood cell, fresh frozen plasma consumption intraoperatively, and the time of hepatectomy were significantly higher; ICU treatment days, respiration time was longer and mortality rate was higher. Almost the whole examination period pHi was mostly below 7.3 and PrCO2 above 50 mmHg in group 2. There were significant differences in pHi between the groups from the preparation phase until the 24th post‐operative hour. In group 2, there were significantly lower values in cardiac output in the whole examination period and in the mean arterial pressure values in the revascularization phase. In group 1, the oxygen delivery values were significantly higher in the preparation phase and oxygen consumption values after revascularization phase. With regression analysis there were no significant correlations between pHi, PrCO2 and global haemodynamic parameters.

Conclusion: Regional parameters were completely different from global haemodynamic parameters, therefore pHi and PrCO2 can be a good indicator of the early liver graft dysfunction.
Gastroesophageal reflux disease in lung transplant recipients
Authors: Hadjiliadis Denis , Duane Davis R , Steele Mark P , Messier Robert H , Lau Christine L , Eubanks Steve S , Palmer Scott M
Published: July 2003

Abstract: Background: Chronic allograft dysfunction after lung transplantation contributes to poor long‐term survival. A link between gastric aspiration and post‐transplant lung dysfunction has been suggested, but little is known about the significance of gastroesophageal reflux disease (GERD) after lung transplantation.

Methods: A retrospective study was performed to determine the prevalence of GERD in lung transplant recipients. Patients who underwent lung transplantation at Duke University, survived at least 6 months and had post‐transplant 24‐h pH studies were included in the analysis. Antireflux medications were discontinued prior to the pH study. Demographic data, pH study date and results, FEV1 at the time of the pH study, confirmed acute rejection episodes, and current medications were collected. The FEV1 ratio was calculated at the time of pH study (current FEV1/best post‐transplant FEV1).

Results: Forty‐three patients met entry criteria. Studies were performed at a median of 558 d post‐transplant. Thirty of forty‐three (69.8%) patients tested had abnormal total acid contact times (normal: <5%). The mean acid contact times for all patients were 10% total, 11.8% upright and 7.9% supine. A negative correlation was found between total or upright acid reflux and FEV1 ratio at the time of studies (−0.341 and −0.419; p = 0.025 and p = 0.005, respectively). The effect of acid reflux on FEV1 ratio remained significant after multivariable analysis.

Conclusions: There is a high prevalence of GERD among selected lung transplant recipients who had pH studies performed and its presence is associated with worse pulmonary function. Future studies are needed to assess whether GERD contributes to the pathogenesis of bronchiolitis obliterans syndrome (BOS).
Basiliximab plus low‐dose cyclosporin vs. OKT3 for induction immunosuppression following renal transplantation
Authors: Kode Ravi , Fa Kosunarty , Chowdhury Shoaib , Ranganna Karthik , Fyfe Billie , Stabler Susan , Damask Anna , Laftavi Mark R , Kumar Anil Mysore , Pankewycz Oleh
Published: July 2003

Abstract: Background:  Current immunosuppressive therapies are very effective in preventing acute rejection (AR) and graft loss following renal transplantation. Newer agents now make it possible to develop equally efficacious but better tolerated and less toxic strategies. This is especially relevant for our ageing recipients. We now compare the efficacy of basiliximab combined with early low‐dose cyclosporin therapy to standard OKT3 induction therapy.

Methods: In this single‐centre study, 100 consecutive recipients of cadaveric kidney transplants from November 1998 to August 2000 were treated with basiliximab combined with early low‐dose cyclosporin, reduced steroids and mycophenolate mofetil (MMF). Clinical outcomes at 100 d and 1 yr were compared with a group of 26 patients transplanted from March 1995 to November 1998 who received OKT3, delayed full‐dose cyclosporin, high‐dose steroids and MMF. Amongst basiliximab treated patients, we compared clinical outcomes in those older and younger than 60 yr.

Results: Both groups were similar except for a shorter cold ischaemic time in the basiliximab group. Length of stay, number of readmissions, total hospitalization days and cytomegalovirus infections were lower in the basiliximab group. Despite a 40% reduction in steroids, basiliximab‐treated patients had fewer biopsy‐proven episodes of AR (basiliximab 14% vs. OKT3 35%) and required less antilymphocyte antibody therapy. Clinical outcomes including patient and graft survival were no different between groups. Long‐term graft survival for patients over 60 yr was limited primarily by mortality.

Conclusions: Compared with OKT3 induction therapy, the combination of early low‐dose cyclosporin and basiliximab is steroid sparing, effective, well tolerated and relatively safe.
Radiofrequency ablation causes ‘thermal fixation’ of hepatocellular carcinoma: a post‐liver transplant histopathologic study
Authors: Coad James E , Kosari Kambiz , Humar Abhinav , Sielaff Timothy D
Published: July 2003

Abstract:Radiofrequency ablation (RFA) is increasingly used to treat hepatocellular carcinoma (HCC) in patients awaiting a liver transplant. Despite its increasing use, detailed histologic information is scarce regarding the nature of RFA‐treated lesions. We identified four chronic hepatitis C patients who had RFA of their HCC before their liver transplant. For these four patients, we conducted a detailed histopathologic analysis of the treated lesions in their explanted livers. The five lesions included immediate (4 d) and long‐term (14 months) post‐RFA specimens. Of the five lesions, four were completely ablated. The one incompletely ablated lesion was also treated with chemoembolization. In the acute post‐RFA period, a zone of interstitial hemorrhage occurred at the outer boundary of the lesion. Differing from classic tissue necrosis, the treated lesions all showed ‘thermal fixation’, with preserved tissue architecture and microscopic cellular detail. The cellular staining characteristics faded with time, but the treated tissue became brittle, resisted tissue breakdown, and generated a minimal wound healing response. At the periphery of the lesion, the fibrous septae of the cirrhotic liver and vascular structures appeared to demarcate or limit progression of the ablation front. A narrow hypocellular fibrous boundary with a focal ‘foreign body’ giant cell‐type reaction developed around the edge of the ablation zone. Thus, RFA can produce immediate and complete thermal fixation of select lesions with an appropriate liver margin and can provide a satisfactory treatment option for select HCC patients before a liver transplant.
Fluvastatin reduces atherogenic lipids without any effect on native endothelial function early after kidney transplantation
Authors: Åsberg Anders , Holdaas Hallvard , Jardine Alan G , Edvardsen Cecilie , Hartmann Anders
Published: July 2003

Abstract:  Background:  Cardiovascular risk is greatly increased in renal transplant recipients. 3‐hydroxy‐3‐methylglutaryl coenzyme A (HMG‐CoA) reductase inhibitor (statin) therapy may reduce cardiovascular risk by improving both dyslipidemia and endothelial function. We therefore performed this study to assess the effect of fluvastatin on endothelial function in renal transplant recipients.

Methods: This randomized, placebo‐controlled, double‐blind designed study investigated the effect of fluvastatin on endothelial function. Thirty‐seven recipients received fluvastatin 40 mg/d and 35 received placebo during the first 12 wk following transplantation. All patients initially received cyclosporin A, prednisolone and azathioprine. At the end of treatment, endothelial function was assessed in the forearm skin microvasculature by laser Doppler flowmetry following acetylcholine stimulation. Samples were taken for measurements of serum lipids and vasoactive markers.

Results: There were no differences in endothelial function between fluvastatin recipients and controls, AUCACh was 656 ± 479 and 627 ± 518 AU min, respectively (fluv vs. control, p > 0.65). In the placebo limb, total cholesterol and LDL cholesterol increased 22 ± 12% and 22 ± 18%, respectively in the first 12 wk following transplantation. The respective values were 18 ± 13% (p = 0.010) and 34 ± 19% (p = 0.0013) lower at 12 wk in the fluvastatin treated patients. Plasma ET‐1, BigET‐1 and urinary excretion of cGMP were not significantly different between treatment groups (p > 0.55).

Conclusion: Although fluvastatin 40 mg/d significantly lowers cholesterol it does not affect endothelial function the first 3 months after renal transplantation. The lack of effect on endothelial function is consistent with a lack of effect on vasoactive substances.
Transplant recipients’ conceptions of three key phenomena in transplantation: the organ donation, the organ donor, and the organ transplant
Authors: Sanner Margareta A
Published: July 2003

Abstract:Thirty‐five heart and kidney transplant patients were interviewed on five separate occasions during the first 2 yr after transplantation. The aim was to explore their experiences of phenomena that distinguish the transplantation from other kinds of medical treatment. The selection of informants was designed to permit comparisons between recipients with heart and kidney transplants and with living and necro‐transplants. The qualitative analysis of the informants’ reactions was focused on three themes; nine categories emerged. The first theme concerned general aspects of the donation and the donor and was differentiated in four categories: joy and sorrow, gratefulness and indebtedness, guilt, and inequity. The second theme related to the donor as a unique individual and included three categories: recognition and identification with the donor, influences of the donor, and relationship to the living donor. The third theme pertained to incorporation of the transplant and included two categories related to the naturalness of having a transplant, and the benevolent transplant. The informants’ reactions were discussed in terms of primary and secondary processes. All informants were in an emotionally charged situation after transplantation and warded off anxiety‐provoking impulses, most intensively during the first 6 months. Avoidance, suppression, and denial were the most common defence mechanisms, all of which seemed to be supported by the medical context. Other, more constructive strategies are suggested. The recipients’ own interpretations of causes to possible personality changes are discussed. There were few differences between heart and necro‐kidney patients concerning the reactions to the donation, the donor, and the transplant; the dividing line was more prominent between recipients with living and necro‐transplants.
Pulsatile machine perfusion vs. cold storage of kidneys for transplantation: a rapid and systematic review
Authors: Wight Jeremy P , Chilcott Jim B , Holmes Mike W , Brewer Naomi
Published: July 2003

Abstract:Objective:To identify and prioritize key areas for further research in kidney preservation systems.

Materials and methods:We conducted a systematic review and meta‐analysis of the effectiveness of machine perfusion and cold storage techniques in reducing delayed graft function (DGF) and improving graft survival in recipients of kidneys from beating and non‐heart‐beating donors. Literature quantifying the link between DGF and graft survival was used to evaluate the potential long‐term impact of machine perfusion and cold storage systems. Cox proportional hazards modelling was used to predict graft survival and graft years gained over 10 yr. Monte Carlo sensitivity analysis was conducted to evaluate stochastic uncertainties within the model.

Results:Machine perfusion leads to a relative risk of DGF of approximately 80% (67%, 96%) compared with cold storage, although the evidence base is limited in quality and study size. Direct evidence on graft survival at 1 yr demonstrates no statistically significant difference between machine perfusion and cold storage. Predictions based upon quantifying the link between DGF and graft survival suggest potential improvements of between 0 and 6% at 10 yr.

Discussion:Studies of high methodological quality and sufficient size are required to determine whether machine preservation leads to reduce rates of DGF. Predicted impact on graft survival implies that direct evidence would require a large population followed up over a long period of time. Registry database analysis supported by validation of the link between DGF and graft survival may be preferable and more feasible than randomized controlled trials.