bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in the Human Matrix Metalloproteinase-9 Gene Is Associated With Arterial Stiffness in Healthy Individuals
Authors: Yasmin  , McEniery Carmel M. , O’Shaughnessy Kevin M. , Harnett Patrick , Arshad Asif , Wallace Sharon , Maki-Petaja Kaisa , McDonnell Barry , Ashby Mike J. , Brown John , Cockcroft John R. , Wilkinson Ian B.
Published: May 2006

Background—

Arterial stiffness is an important determinant of cardiovascular risk. Elastin is the main elastic component of the arterial wall and can be degraded by a number of enzymes including serine proteases and matrix metalloproteinases (MMPs). Serum MMP-9 levels correlate with arterial stiffness and predict cardiovascular risk. Polymorphisms in the MMP-9 gene are also associated with large artery function in subjects with coronary artery disease. Therefore, we investigated the influence of known MMP-9 (−1562C>T, R279Q) polymorphisms on arterial stiffness in a large cohort of healthy individuals (n=865).

Methods and Results—

Aortic pulse wave velocity (PWV) and augmentation index were assessed. Supine blood pressure, biochemical markers, MMP-9 levels, and serum elastase activity (SEA) were also determined. Genomic DNA was extracted and genotyping performed. Aortic PWV, serum MMP-9, and SEA were higher in carriers of the rare alleles for the −1562C>T and R279Q polymorphisms. These polymorphisms were also associated with aortic PWV after correction for other confounding factors. Stepwise regression models with known or likely determinants of arterial stiffness revealed that ≈60% of the variability in aortic PWV was attributable to age, mean arterial pressure, and genetic variants (
P
<0.001).

Conclusions—

We have demonstrated for the first time that aortic stiffness and elastase activity are influenced by MMP-9 gene polymorphisms. This suggests that the genetic variation in this protein may be involved in the process of large artery stiffening.
Neural Crest Cells Retain Multipotential Characteristics in the Developing Valves and Label the Cardiac Conduction System
Authors: Nakamura Tomoki , Colbert Melissa C. , Robbins Jeffrey
Published: May 2006

Multipotent neural crest cells (NCCs) are a major extracardiac component of cardiovascular development. Although recognized as contributing cells to the arterial valves at early developmental stages, NCC persistence in the valves at later times or in the adult heart is controversial. We analyzed NCC persistence and contributions to both semilunar and atrioventricular (AV) valves in the mature heart. Two NCC-specific promoters driving Cre recombinase, Wnt1-Cre and P0-Cre, were mated with floxed reporter mice, R26R or CAG-CAT-EGFP, to map NCC fate. Hearts were analyzed before aorticopulmonary (AP) septation through adult stages. As previously demonstrated, strong NCC labeling was detected in ventral and dorsal outflow cushions before AP septation. In contrast to previous reports, we found that substantial numbers of labeled cells persisted in the semilunar valves in late fetal, neonatal, and adult hearts. Furthermore, NCCs were also found in the AV valves, almost exclusively in the septal leaflets. NCCs in the AV valves expressed melanocytic and neurogenic markers. However, cells labeled in the proximal cardiac conduction system exhibited neurogenic and gliagenic markers, whereas some NCCs expressed no differentiation specific markers. These results suggest that cardiac NCCs contribute to the mature valves and the cardiac conduction system and retain multipotent characteristics late in development.
Maximum Phosphorylation of the Cardiac Ryanodine Receptor at Serine-2809 by Protein Kinase A Produces Unique Modifications to Channel Gating and Conductance Not Observed at Lower Levels of Phosphorylation
Authors: Carter Simon , Colyer John , Sitsapesan Rebecca
Published: May 2006

It is suggested that protein kinase A (PKA)-dependent phosphorylation of cardiac ryanodine receptors (RyR2) is linked to the development of heart failure and the generation of fatal cardiac arrhythmias. It is also suggested that RyR2 is phosphorylated to 75% of maximum levels in heart failure resulting in leaky, unregulated channels gating in subconductance states. We now demonstrate that this is unlikely, as RyR2 isolated from nonfailing cardiac muscle is phosphorylated to 75% of maximum at serine-2809, and in this situation, RyR2 displays low open probability (
P
o
) (0.059±0.010 [SEM]; n=30) and normal regulation of gating by Ca
2+
and other ligands. However, when serine-2809 is PKA phosphorylated to maximum levels on RyR2, unique changes in channel behavior are observed. The channel displays enhanced single-channel conductance, very long open states causing large increases in
P
o
, and no evidence of subconductance states. Dephosphorylation of channels by protein phosphatase 1 (from 75% to near 0% at serine-2809) also enhances RyR2 channel activity through abbreviation of closed lifetimes. We propose that channels phosphorylated to 75% of maximum at serine-2809 occupy a natural low point in the RyR2 activity landscape. This optimizes channel control, which can be accomplished either by enhanced or decreased phosphorylation, making the channel particularly sensitive to the kinase:phosphatase balance. Pathological situations such as heart failure might upset this balance and thereby permit prolonged stoichiometric phosphorylation of serine-2809, which would be required for dysregulation of SR Ca
2+
release.
Hypoxia Inducible Factor 1 Mediates Hypoxia-Induced TRPC Expression and Elevated Intracellular Ca
2+
in Pulmonary Arterial Smooth Muscle Cells
Authors: Wang Jian , Weigand Letitia , Lu Wenju , Sylvester J.T. , L. Semenza Gregg , Shimoda Larissa A.
Published: May 2006

Chronic hypoxia (CH) causes pulmonary vasoconstriction because of increased pulmonary arterial smooth muscle cell (PASMC) contraction and proliferation. We previously demonstrated that intracellular Ca
2+
concentration ([Ca
2+
]
i
) was elevated in PASMCs from chronically hypoxic rats because of Ca
2+
influx through pathways other than L-type Ca
2+
channels and that development of hypoxic pulmonary hypertension required full expression of the transcription factor hypoxia inducible factor 1 (HIF-1). In this study, we examined the effect of CH on the activity and expression of store-operated Ca
2+
channels (SOCCs) and the regulation of these channels by HIF-1. Capacitative Ca
2+
entry (CCE) was enhanced in PASMCs from intrapulmonary arteries of rats exposed to CH (10% O
2
; 21 days), and exposure to Ca
2+
-free extracellular solution or SOCC antagonists (SKF96365 or NiCl
2
) decreased resting [Ca
2+
]
i
in these cells. Expression of TRPC1 and TRPC6, but not TRPC4, mRNA and protein was increased in PASMCs from rats and wild-type mice exposed to CH, in PASMCs from normoxic animals cultured under hypoxic conditions (4% O
2
; 60 hours), and in PASMCs in which HIF-1 was overexpressed under nonhypoxic conditions. Hypoxia-induced increases in basal [Ca
2+
]
i
and TRPC expression were absent in mice partially deficient for HIF-1. These results suggest that increased TRPC expression, leading to enhanced CCE through SOCCs, may contribute to hypoxic pulmonary hypertension by facilitating Ca
2+
influx and increasing basal [Ca
2+
]
i
in PASMCs and that this response is mediated by HIF-1.
Formation of the Venous Pole of the Heart From an
Nkx2–5
–Negative Precursor Population Requires
Tbx18
Authors: Christoffels Vincent M. , Mommersteeg Mathilda T.M. , Trowe Mark-Oliver , Prall Owen W.J. , de Gier-de Vries Corrie , Soufan Alexandre T. , Bussen Markus , Schuster-Gossler Karin , Harvey Richard P. , Moorman Antoon F.M. , Kispert Andreas
Published: May 2006

The venous pole of the mammalian heart is a structurally and electrically complex region, yet the lineage and molecular mechanisms underlying its formation have remained largely unexplored. In contrast to classical studies that attribute the origin of the myocardial sinus horns to the embryonic venous pole, we find that the sinus horns form only after heart looping by differentiation of mesenchymal cells of the septum transversum region into myocardium. The myocardial sinus horns and their mesenchymal precursor cells never express
Nkx2–5
, a transcription factor critical for heart development. In addition, lineage studies show that the sinus horns do not derive from cells previously positive for
Nkx2–5
. In contrast, the sinus horns express the T-box transcription factor gene
Tbx18
. Mice deficient for
Tbx18
fail to form sinus horns from the pericardial mesenchyme and have defective caval veins, whereas the pulmonary vein and atrial structures are unaffected. Our studies define a novel heart precursor population that contributes exclusively to the myocardium surrounding the sinus horns or systemic venous tributaries of the developing heart, which are a source of congenital malformation and cardiac arrhythmias.
Interannual Rainfall Extremes over Southwest Western Australia Linked to Indian Ocean Climate Variability
Authors: England Matthew H. , Ummenhofer Caroline C. , Santoso Agus
Published: May 2006

Interannual rainfall extremes over southwest Western Australia (SWWA) are examined using observations, reanalysis data, and a long-term natural integration of the global coupled climate system. The authors reveal a characteristic dipole pattern of Indian Ocean sea surface temperature (SST) anomalies during extreme rainfall years, remarkably consistent between the reanalysis fields and the coupled climate model but different from most previous definitions of SST dipoles in the region. In particular, the dipole exhibits peak amplitudes in the eastern Indian Ocean adjacent to the west coast of Australia. During dry years, anomalously cool waters appear in the tropical/subtropical eastern Indian Ocean, adjacent to a region of unusually warm water in the subtropics off SWWA. This dipole of anomalous SST seesaws in sign between dry and wet years and appears to occur in phase with a large-scale reorganization of winds over the tropical/subtropical Indian Ocean. The wind field alters SST via anomalous Ekman transport in the tropical Indian Ocean and via anomalous air–sea heat fluxes in the subtropics. The winds also change the large-scale advection of moisture onto the SWWA coast. At the basin scale, the anomalous wind field can be interpreted as an acceleration (deceleration) of the Indian Ocean climatological mean anticyclone during dry (wet) years. In addition, dry (wet) years see a strengthening (weakening) and coinciding southward (northward) shift of the subpolar westerlies, which results in a similar southward (northward) shift of the rain-bearing fronts associated with the subpolar front. A link is also noted between extreme rainfall years and the Indian Ocean Dipole (IOD). Namely, in some years the IOD acts to reinforce the eastern tropical pole of SST described above, and to strengthen wind anomalies along the northern flank of the Indian Ocean anticyclone. In this manner, both tropical and extratropical processes in the Indian Ocean generate SST and wind anomalies off SWWA, which lead to moisture transport and rainfall extremes in the region. An analysis of the seasonal evolution of the climate extremes reveals a progressive amplification of anomalies in SST and atmospheric circulation toward a wintertime maximum, coinciding with the season of highest SWWA rainfall. The anomalies in SST can appear as early as the summertime months, however, which may have important implications for predictability of SWWA rainfall extremes.
Synoptic-Scale Atmospheric Circulation and Boreal Canada Summer Drought Variability of the Past Three Centuries
Authors: Girardin Martin-Philippe , Tardif Jacques C. , Flannigan Mike D. , Bergeron Yves
Published: May 2006

Five independent multicentury reconstructions of the July Canadian Drought Code and one reconstruction of the mean July–August temperature were developed using a network of 120 well-replicated tree-ring chronologies covering the area of the eastern Boreal Plains to the eastern Boreal Shield of Canada. The reconstructions were performed using 54 time-varying reconstruction submodels that explained up to 50% of the regional drought variance during the period of 1919–84. Spatial correlation fields on the six reconstructions revealed that the meridional component of the climate system from central to eastern Canada increased since the mid–nineteenth century. The most obvious change was observed in the decadal scale of variability. Using 500-hPa geopotential height and wind composites, this zonal to meridional transition was interpreted as a response to an amplification of long waves flowing over the eastern North Pacific into boreal Canada, from approximately 1851 to 1940. Composites with NOAA Extended Reconstructed SSTs indicated a coupling between the meridional component and tropical and North Pacific SST for a period covering at least the past 150 yr, supporting previous findings of a summertime global ocean–atmosphere–land surface coupling. This change in the global atmospheric circulation could be a key element toward understanding the observed temporal changes in the Canadian boreal forest fire regimes over the past 150 yr.
Factors Limiting Convective Cloud-Top Height at the ARM Nauru Island Climate Research Facility
Authors: Jensen Michael P. , Del Genio Anthony D.
Published: May 2006

Cumulus congestus clouds, with moderate shortwave albedos and cloud-top temperatures near freezing, occur fairly often in the Tropics. These clouds may play an important role in the evolution of the Madden–Julian oscillation and the regulation of relative humidity in the midtroposphere. Despite this importance they are not necessarily simulated very well in global climate models. Surface remote sensing observations and soundings from the Atmospheric Radiation Measurement (ARM) climate research facility at Nauru Island are coupled with a simple parcel model in order to address the following questions about these cloud types: 1) Which environmental factors play a role in determining the depth of tropical convective clouds? 2) What environmental parameters are related to entrainment rate in cumulus congestus clouds? The results presented herein suggest that at Nauru Island a drying of the midtroposphere is more likely to be responsible for limiting congestus cloud-top heights than is a stabilizing of the freezing level. It is also found that low-level CAPE and the RH profile account for the largest portion of the variance in cumulus congestus entrainment rates, consistent with the idea that entrainment rate depends on the buoyant production of turbulent kinetic energy. If the analysis is limited to cases where there is a sounding during the hour preceding the cumulus congestus observations, it is found that the low-level CAPE accounts for 85% of the total variance in entrainment rate.
Anthropogenic Warming of the Oceans: Observations and Model Results
Authors: Pierce David W. , Barnett Tim P. , AchutaRao Krishna M. , Gleckler Peter J. , Gregory Jonathan M. , Washington Warren M.
Published: May 2006

Observations show the oceans have warmed over the past 40 yr, with appreciable regional variation and more warming at the surface than at depth. Comparing the observations with results from two coupled ocean–atmosphere climate models [the Parallel Climate Model version 1 (PCM) and the Hadley Centre Coupled Climate Model version 3 (HadCM3)] that include anthropogenic forcing shows remarkable agreement between the observed and model-estimated warming. In this comparison the models were sampled at the same locations as gridded yearly observed data. In the top 100 m of the water column the warming is well separated from natural variability, including both variability arising from internal instabilities of the coupled ocean–atmosphere climate system and that arising from volcanism and solar fluctuations. Between 125 and 200 m the agreement is not significant, but then increases again below this level, and remains significant down to 600 m. Analysis of PCM’s heat budget indicates that the warming is driven by an increase in net surface heat flux that reaches 0.7 W m−2 by the 1990s; the downward longwave flux increases by 3.7 W m−2, which is not fully compensated by an increase in the upward longwave flux of 2.2 W m−2. Latent and net solar heat fluxes each decrease by about 0.6 W m−2. The changes in the individual longwave components are distinguishable from the preindustrial mean by the 1920s, but due to cancellation of components, changes in the net surface heat flux do not become well separated from zero until the 1960s. Changes in advection can also play an important role in local ocean warming due to anthropogenic forcing, depending on the location. The observed sampling of ocean temperature is highly variable in space and time, but sufficient to detect the anthropogenic warming signal in all basins, at least in the surface layers, by the 1980s.
Climatology and ENSO-Related Variability of North American Extratropical Cyclone Activity
Authors: Eichler Timothy , Higgins Wayne
Published: May 2006

The climatology and interannual variability of North American extratropical cyclones are examined using 6-hourly sea level pressure data from the NCEP–NCAR reanalysis for the period 1950–2002 and ECMWF 40-yr Re-Analysis (ERA-40) data from 1971 to 2000. The climatology includes an evaluation of the seasonal frequency and intensity of storms as well as an analysis of extreme event intensity. ENSO variability is evaluated by ENSO phase with emphasis on boreal winter. Results show an enhanced East Coast storm track during El Niño as well as an equatorward shift in storm tracks in the North Pacific for storms generated from both the NCEP–NCAR reanalysis and ERA-40 datasets. Observed precipitation close to a storm’s center is used to determine which phase of the ENSO cycle is associated with the most productive storms and where they occur. During El Niño winters, a precipitation maximum is located east of the Appalachians and is associated with an enhanced East Coast storm track. During La Niña winters, the precipitation maximum shifts to the Ohio Valley and is associated with an enhanced Great Lakes storm track. Along the U.S. west coast, there is a precipitation maximum in the Pacific Northwest during La Niña winters, which is due to a storm track west of Washington State.
Impact of Regional SST Anomalies on the Indian Monsoon Response to Global Warming in the CNRM Climate Model
Authors: Douville H.
Published: May 2006

While transient climate change experiments with coupled atmosphere–ocean general circulation models undoubtedly represent the most comprehensive tool for studying the climate response to increasing concentrations of greenhouse gases (GHGs), less computationally expensive time-slice experiments with atmospheric GCMs are still useful to test the robustness of the projected climate change. In the present study, three sets of time-slice experiments with prescribed sea surface temperature (SST) are compared to a reference climate scenario obtained with the Centre National de Recherches Météorologiques Coupled Climate Model (CCM). The main objective is to assess the sensitivity of the monsoon response to the magnitude or pattern of SST anomalies in two regions where such anomalies are highly model dependent, namely, the circumpolar Southern Ocean and the tropical Pacific Ocean. On the one hand, it is shown that the regional climate anomalies predicted by the CCM can be reproduced at least qualitatively by a pair of time-slice experiments in which the present-day SST biases of the CCM are removed. On the other hand, the results indicate that the Indian monsoon response to increasing amounts of GHG is sensitive to regional uncertainties in the prescribed SST warming. Increasing the sea surface warming in the southern high latitudes to compensate for the weak sea ice feedback simulated by the CCM around the Antarctic has a significant influence on the regional climate change simulated over India, through a perturbation of the regional Hadley circulation. Prescribing zonal mean rather than El Niño–like SST anomalies in the tropical Pacific has an even stronger impact on the monsoon response, through a modification of the Walker circulation. These results suggest that both deficiencies in simulating present-day climate (even at high latitudes) and uncertainties in the SST patterns caused by enhanced GHG concentrations (especially in the tropical Pacific) are major obstacles for predicting climate change at the regional scale.
Decadal Variability in the Kuroshio–Oyashio Extension Simulated in an Eddy-Resolving OGCM
Authors: Nonaka Masami , Nakamura Hisashi , Tanimoto Youichi , Kagimoto Takashi , Sasaki Hideharu
Published: May 2006

Through analysis of a hindcast integration of an eddy-resolving quasi-global ocean general circulation model, decadal variability in the Kuroshio–Oyashio Extension region is investigated, with particular emphasis on that of the subarctic (Oyashio) and the Kuroshio Extension (KE) fronts. The KE front is deep and is accompanied by a sharp sea surface height (SSH) gradient with modest sea surface temperature (SST) gradient. In contrast, the subarctic front is shallow and is recognized as a zone of tight gradient in SST but not SSH.

As a decadal-scale change from a warm period around 1970 to a cool period in the mid-1980s, those fronts in the model migrate southward as observed, and the associated pronounced cooling is confined mainly to those frontal zones. Reflecting the distinctive vertical structure of the fronts, the mixed layer cooling is the strongest along the subarctic front, whereas the subsurface cooling and the associated salinity changes are most pronounced along the KE front. Concomitantly with their southward migration, the two fronts have undergone decadal-scale intensification. Associated with reduced heat release into the atmosphere, the cooling in the frontal zones can be attributed neither to the direct atmospheric thermal forcing nor to the advective effect of the intensified KE, while the advective effect by the intense Oyashio can contribute to the cooling in the subarctic frontal zone.

In fact, their time evolution is not found to be completely coherent, suggesting that their variability may be governed by different mechanisms. Decadal SSH variability in the KE frontal zone seems to be largely explained by propagation of baroclinic Rossby waves forced by anomalous Ekman pumping in the central North Pacific. This process alone cannot fully explain the corresponding variability in the subarctic frontal zone, where eastward propagating SSH anomalies off the Japanese coast seem to be superimposed on the Rossby wave signals.
Attribution of the Late-Twentieth-Century Rainfall Decline in Southwest Australia
Authors: Timbal Bertrand , Arblaster Julie M. , Power Scott
Published: May 2006

There was a dramatic decrease in rainfall in the southwest of Australia (SWA) in the mid-1960s. A statistical method, based on the idea of analogous synoptic situations, is used to help clarify the cause of the drying. The method is designed to circumvent error in the rainfall simulated directly by a climate model, and to exploit the ability of the model to simulate large-scale fields reasonably well. The method uses relationships between patterns of various atmospheric fields with station records of rainfall to improve the simulation of the local rainfall spatial variability. The original technique was developed in a previous study. It is modified here for application to two four-member ensembles of simulations of the climate from 1870 to 1999 performed with the Parallel Climate Model (PCM). The first ensemble, called “natural,” is forced with natural variations in both volcanic activity and solar forcing. The second ensemble, called “full forcing,” also includes three types of human-induced forcing resulting from changes in greenhouse gases, ozone, and aerosols. The full-forcing runs provide a better match to observational changes in sea surface temperature in the vicinity of SWA. The observed rainfall decline is not well captured by rainfall changes simulated directly by the model in either ensemble. There is a hint that the fully forced ensemble is more realistic, but it is nothing more than a hint. The downscaling approach, on the other hand, provides a much more accurate reproduction of the day-to-day variability of rainfall in SWA than the rainfall simulated directly by the model. The downscaled ensemble mean rainfall in full forcing declines over the region with a spatial pattern that is similar to the observed decline. This contrasts with an increase of rainfall in the downscaled rainfall in the natural ensemble. These results give the clearest indication yet that anthropogenic forcing played a role in the drying of SWA. Note, however, that ambiguities remain. For example, although the observed decline fits within the range of downscaled model simulation, the ensemble mean rainfall decline is only about half of the observed estimate, the timing differs from the observations, drying did not occur in the downscaling of one of the four full-forced ensemble members, and not all potential forcing mechanisms are included in full forcing (e.g., land surface changes). Furthermore, while the observed rainfall decline was a sharp reduction in the 1960s, followed by a near-constant rainfall regime, the full-forcing ensemble suggests a more gradual rainfall decline over 40 yr from 1960.
Weakening of North Indian SST Gradients and the Monsoon Rainfall in India and the Sahel
Authors: Chung Chul Eddy , Ramanathan V.
Published: May 2006

Sea surface temperatures (SSTs) in the equatorial Indian Ocean have warmed by about 0.6–0.8 K since the 1950s, accompanied by very little warming or even a slight cooling trend over the northern Indian Ocean (NIO). It is reported that this differential trend has resulted in a substantial weakening of the meridional SST gradient from the equatorial region to the South Asian coast during summer, to the extent that the gradient has nearly vanished recently. Based on simulations with the Community Climate Model Version 3 (CCM3), it is shown that the summertime weakening in the SST gradient weakens the monsoon circulation, resulting in less monsoon rainfall over India and excess rainfall in sub-Saharan Africa. The observed trend in SST is decomposed into a hypothetical uniform warming and a reduction in the meridional gradient. The uniform warming of the tropical Indian Ocean in the authors’ simulations increases the Indian summer monsoon rainfall by 1–2 mm day−1, which is opposed by a larger drying tendency due to the weakening of the SST gradient. The net effect is to decrease the Indian monsoon rainfall, while preventing the sub-Saharan region from becoming too dry. Published coupled ocean–atmosphere model simulations are used to describe the competing effects of the anthropogenic radiative forcing due to greenhouse gases and the anthropogenic South Asian aerosols on the observed SST gradient and the monsoon rainfall.
Osteochondral Autograft Transplantation in the Porcine Knee
Authors: Harman Bradley D. , Weeden Steven H. , Lichota Derek K. , Brindley George W.
Published: May 2006

Background

Knee articular cartilage defects are not an uncommon problem. Because articular cartilage is limited in its ability to heal, these defects are difficult to manage.

Hypothesis

Osteochondral autografts will provide less of a cavitary defect and more viable hyaline articular cartilage than will control knees.

Study Design

Controlled laboratory study.

Methods

Osteochondral autografts were grossly and microscopically evaluated in the porcine knee and compared with a control at 6 weeks, 3 months, and 6 months. In 18 porcine specimens, a 1-stage surgical procedure was performed to harvest an osteochondral graft from a nonweightbearing articular cartilage surface, and the graft was transplanted into a defect created in the weightbearing region of the medial femoral condyle. In the opposite control knee, a similar defect was created in the medial femoral condyle; an osteochondral transplant was not performed. Six pigs each were sacrificed at 6 weeks, 3 months, and 6 months.

Results

Gross inspection of the control knees showed a cavitary defect. The defect grossly decreased in size with fibrous ingrowth seen on microscopic analysis. An increasing amount of fibrous tissue and fibrocartilage was present at the 3 time periods. Gross inspection of the graft knee showed a healed osteochondral plug with no obvious displacement, cavitary defects, or surrounding necrotic tissue at each time interval. Microscopic analysis revealed the graft knee contained viable hyaline cartilage and healed viable subchondral bone. At all time intervals, 75% to 100% of the hyaline cartilage was viable in all specimens. In 6-month specimens, bridging cartilage at the autograft-host junction was incomplete in 50%, partial in 33%, and complete in 17%.

Conclusion

Osteochondral autografts in the porcine knee resulted in viable hyaline cartilage for up to 6 months; there was inconsistent bridging hyaline cartilage at the periphery. Grafts appeared to heal into existing subchondral bone without displacement or evidence of necrosis.

Clinical Relevance

This type of osteochondral transplant can be used as a reliable reconstructive alternative for osteochondral defects.
Corporate Governance and Shareholder Value Analysis
Authors: Sinha Rajeeva
Published: May 2006

In corporate governance today, there is a lot of emphasis on structural reform. Individual aspects of the board have increasingly been the focus of policy reform and shareholder activism. Specific attributes of board structure like the separation of the posts of chairperson and the CEO, percentage of outside directors on the board, etc., have become important considerations in the quest for effective corporate governance. In contrast, taking a process view of corporate governance, this article examines the utility of shareholder value analysis for corporate governance. In value-based management, shareholder value maximization is set as the objective of the firm. The adoption of this objective as the goal of the firm can promote effective corporate governance in three ways. First, it provides the necessary ‘pre-commitment’ between shareholders and managers regarding the goal of the firm. Second, it necessitates a greater flow of firm-specific information and the disaggregation of financial information. In corporate governance a clear identification of the goal of the firm and firm-specific information is important because of the incomplete contracts between shareholders and managers. Substantive flows of firm-specific information are needed to bridge the gaps in the incomplete contracts. Shareholder value management techniques, by providing this information in a non-agency context can provide a valuable input towards effective corporate governance. Finally, the goal of shareholder wealth maximization ensures a closer interdependence between strategy formation and the setting of operational objectives for managerial decisions. We illustrate some of these points with examples from the Lloyds–TSB experience of implementing shareholder value analysis and the findings of a study on investor communication.
Perception Study of Cyber Café Users
Authors: Chawla Deepak , Behl Ramesh
Published: May 2006

The main objective of this article is to study the perception of the users of cyber cafés and to understand the important factors required to manage the cafés better in a competing environment. This was pursued by interviewing 414 users, in cyber cafés spread over different parts of Delhi. The respondents were chosen in so as to represent both the working and non-working class; those using the cyber cafés in the morning, after-noon, evening and night and belonging to different age groups, sex and education level. The information needed for designing the questionnaire was identified through exploratory research by conducting informal interviews and two focus group discussions of the users. The data was analyzed through the examination of frequency distributions, by conducting a factor analysis and using the chi-square test. Ten factors of perceptions were identified. The study indicated that value added services, state of art technology, effective utilization of time during waiting hours and data production facilities were the most important factors. The article concludes by providing recommendations to cyber café owners.
The Firm's Strategy Type and Market Value
Authors: Kumari Runu , Mitra Devashis , Srinivasan Gopalan
Published: May 2006

The relationship between firm-specific strategies and the firm's value has attracted considerable attention from researchers. The present article seeks to add to the literature by investigating firm-specific business strategy and value. We categorize firms into different ‘strategy clusters’ using the framework developed by Miles and Snow (1978) and examine whether the nature of a firm's strategy has an association with its perceived performance as measured by Tobin's Q.
Gender Influences in Garment Purchase
Authors: Sondhi Neena , Singhvi S.R.
Published: May 2006

The ever-evolving fashion industry is a clear reflection of the changing patterns in the social, political, technological and economic environment of a society. The past few decades have seen significant and diverse changes in consumer habits and lifestyles. At long last, garment purchase has come of age, with both male and female consumers becoming increasingly brand and fashion conscious. With the emergence of a contemporary social structure, garment purchase is no longer the forte of women alone. Research, national and international, expounds on the purchase decisions of the New Man who is becoming more fashion conscious and trend savvy when it comes to apparel. This article is an attempt to identify certain gender-based antecedents of garment purchase involvement. An attempt has also been made to identify the key drivers that influence the decision making process for garment purchase, separately for male and female customers. The findings demonstrate a paradigm shift in attitudes and purchase patterns, which can have important implications for the marketer.
Understanding Employee Stock Options
Authors: Sharma Kapil
Published: May 2006

This article looks into some key aspects related to employee stock options and discusses the reasons behind their widespread. It reviews stock options from a technical aspect and explores the consequences of stock option usage—investigating the impact of stock options on shareholder value—primarily earnings dilution. It also proposes hedging strategies as means of reducing this risk and discusses the concern involved while using hedging strategies.
Problems of Indian Garment Exporters in the Light of Multi-fibre Arrangement (MFA) Phase-out
Authors: Singh Raghbir , Kathuria Lalit Mohan
Published: May 2006

The textile and garment sector is one of India's oldest and most important economic sectors, second only to agriculture in terms of employment, net foreign earnings, and industrial production. Until December 2004, Multi-Fibre Arrangement (MFA) governed the world trade in the textiles and garment sector. From 1 January 2005, it has been regulated by an Agreement on Textile and Clothing (ATC), which paved the way for phase-out of Multi-Fibre Arrangement (MFA). This article analyzes the various problems of Indian garment exporters in the light of MFA phase-out. The article is based on a survey of selected garment exporters of Northern region (Delhi and Ludhiana) and proposes suggestions for policy makers and strategies for garment exporters that will help them in increasing their export share in the world market.
Conflict Management Strategies of Administrators and Teachers
Authors: Balay Refik
Published: May 2006

This study was conducted to understand the conflict management strategies of administrators and teachers. Data was collected from a sample of randomly selected 250 school administrators and teachers working in seventeen primary schools, public and private, in the Van province of East Anatolia, Turkey. Three conflict management strategies (competing, avoiding, and compromising) were examined in terms of task and school type. Results indicated that administrators are more likely to use avoiding and compromising strategies than teachers. Moreover, both administrators and teachers at private primary schools tend to use compromising, avoiding and competing behaviours than their colleagues at public schools.
AirAsia
Authors: Ahmad Rizal , Neal Mark
Published: May 2006

This case details the rise and expansion of AirAsia in South-east Asia. The company employed a business model for low-cost airlines that was originally developed by Southwest Airlines in the United States and subsequently employed with great success by European companies such as Ryanair and EasyJet. The case thus documents the successful application of a western business model in a previously unexploited Asian environment, and raises issues about knowledge transfer, and the sustainability of such a model in the face of increasing competition and market turbulence. In this way, this case raises issues of innovation, adaptation, strategy and sustainability within the Asian context.
Relaunching Adult Diapers in India—Has the Time Come?*
Authors: Patil Ajit , Srinivasan Rahul
Published: May 2006

This case is about the dilemma faced by Supriya, the product manager at Kimberly Clark Lever Private Ltd, India (KCLL). She has to prepare a business plan for the relaunch of adult diapers called ‘Depend’. The same product was introduced into the market in the late 1990s but was later revoked because of poor performance. The case discusses details of demand forecasting and marketing strategy during the initial product launch along with an analysis of the failure. Novelty in the marketing strategy is necessary because in India personal hygiene is not discussed openly either within the family or publicly. The retailers feel that the market for adult diapers had begun to evolve in 2004. This is also indicated by an increase in the number of new brands introduced in 2004–05. Due to the positive changes in the environment, KCLL conducts a market research survey with an aim to estimate demand and gather competitive intelligence. The picture projected by the market research is very positive. The question that needs to be answered is how to make ‘Depend’ commercially viable. If the decision to sell ‘Depend’ directly to the end-user is finalized, Supriya faces a dilemma. She has to prioritize and choose either direct selling or indigenization. KCLL senior executives are not prepared to invest in both the options simultaneously. There is no consensus among the managers on what should be the priority. The views of Supriya's team members on direct selling and indigenization are presented in the case.
Signaling of vascular endothelial growth factor receptor-1 tyrosine kinase promotes rheumatoid arthritis through activation of monocytes/macrophages
Authors: Murakami Masato , Iwai Shinobu , Hiratsuka Sachie , Yamauchi Mai , Nakamura Kazuhide , Iwakura Yoichiro , Shibuya Masabumi
Published: May 2006

Vascular endothelial growth factor (VEGF) and VEGF receptor-1 (VEGFR-1/Flt-1) were shown to be involved in pathological angiogenesis, particularly rheumatoid arthritis (RA). However, the molecular basis of their actions is not fully understood. Here we report that in a murine model of RA, deletion of the tyrosine kinase (TK) domain of VEGFR-1 decreased the incidence and clinical symptoms of RA. Pathological symptoms, such as synovial hyperplasia, inflammatory infiltrates, pannus formation, and cartilage/bone destruction, became milder in Vegfr-1 tk–/– mice compared with wild-type (Wt) mice in the human T-cell leukemia virus-1 (HTLV-1) pX–induced chronic models. VEGFR-1 TK-deficient bone marrow cells showed a suppression of multilineage colony formation. Furthermore, macrophages induced to differentiate in vitro showed a decrease in immunologic reactions such as phagocytosis and the secretion of interleukin-6 (IL-6) and VEGF-A. Treatment of this RA model with a small molecule inhibitor for VEGFR TK, KRN951, also attenuated the arthritis. These results indicate that the VEGFR-1 TK signaling modulates the proliferation of bone marrow hematopoietic cells and immunity of monocytes/macrophages and promotes chronic inflammation, which may be a new target in the treatment of RA.
Induction of FcγRIIA expression in myeloid PLB cells during differentiation depends on cytosolic phospholipase A2 activity and is regulated via activation of CREB by PGE2
Authors: Hazan-Eitan Zahit , Weinstein Yacob , Hadad Nurit , Konforty Aviva , Levy Rachel
Published: May 2006

FcγRIIA expressed on neutrophils and monocytes has a fundamental role in combating bacterial infections. In the present study, the requirement of cytosolic phospholipase A2 (cPLA2) for induction of FcγRIIA expression was studied in a model of cPLA2-deficient PLB-985 cells (PLB-D cells). FcγRIIA was acquired only during differentiation of PLB but not of PLB-D cells induced by either 1,25-dihydroxyvitamin D3, retinoic acid, or interferon γ. Addition of prostaglandin E2 (PGE2) to PLB-D cells undergoing differentiation restored the expression of FcγRIIA protein, whereas addition of indomethacin to PLB cells during differentiation inhibited both the production of PGE2 and the expression of FcγRIIA. Inhibition of PKA during PLB differentiation prevented FcγRIIA expression, whereas dibutyryl cAMP (dbcAMP) induced its expression in both PLB and PLB-D cells. CREB phosphorylation and CREB-CRE interaction were detected only in differentiated PLB cells and not PLB-D cells and were inhibited by indomethacin. A reporter gene containing a FcγRIIA gene promoter fragment with the CRE element was sufficient for CREB activation. Our results are the first to show that CREB activation is involved in up-regulation of FcγRIIA expression in myeloid lineages. PGE2 formed via cPLA2 activates CREB through PKA and this process is dependent on development of PGE2 receptor 4.
Differential gene expression in abdomens of the malaria vector mosquito, Anopheles gambiae, after sugar feeding, blood feeding and Plasmodium berghei infection
Authors: Dana Ali N , Hillenmeyer Maureen E , Lobo Neil F , Kern Marcia K , Romans Patricia A , Collins Frank H
Published: May 2006

Background

Large scale sequencing of cDNA libraries can provide profiles of genes expressed in an organism under defined biological and environmental circumstances. We have analyzed sequences of 4541 Expressed Sequence Tags (ESTs) from 3 different cDNA libraries created from abdomens from Plasmodium infection-susceptible adult female Anopheles gambiae. These libraries were made from sugar fed (S), rat blood fed (RB), and P. berghei-infected (IRB) mosquitoes at 30 hours after the blood meal, when most parasites would be transforming ookinetes or very early oocysts.

Results

The S, RB and IRB libraries contained 1727, 1145 and 1669 high quality ESTs, respectively, averaging 455 nucleotides (nt) in length. They assembled into 1975 consensus sequences – 567 contigs and 1408 singletons. Functional annotation was performed to annotate probable molecular functions of the gene products and the biological processes in which they function. Genes represented at high frequency in one or more of the libraries were subjected to digital Northern analysis and results on expression of 5 verified by qRT-PCR.

Conclusion

13% of the 1965 ESTs showing identity to the A. gambiae genome sequence represent novel genes. These, together with untranslated regions (UTR) present on many of the ESTs, will inform further genome annotation. We have identified 23 genes encoding products likely to be involved in regulating the cellular oxidative environment and 25 insect immunity genes. We also identified 25 genes as being up or down regulated following blood feeding and/or feeding with P. berghei infected blood relative to their expression levels in sugar fed females.
Low serum albumin and the acute phase response predict low serum selenium in HIV-1 infected women
Authors: Drain Paul K , Baeten Jared M , Overbaugh Julie , Wener Mark H , Bankson Daniel D , Lavreys Ludo , Mandaliya Kishorchandra , Ndinya-Achola Jeckoniah O , McClelland R Scott
Published: May 2006

Background

Low serum selenium has been associated with lower CD4 counts and greater mortality among HIV-1-seropositive individuals, but most studies have not controlled for serum albumin and the presence of an acute phase response.

Methods

A cross-sectional study was conducted to evaluate relationships between serum selenium concentrations and CD4 count, plasma viral load, serum albumin, and acute phase response markers among 400 HIV-1-seropositive women.

Results

In univariate analyses, lower CD4 count, higher plasma viral load, lower albumin, and the presence of an acute phase response were each significantly associated with lower serum selenium concentrations. In multivariate analyses including all four of these covariates, only albumin remained significantly associated with serum selenium. For each 0.1 g/dl increase in serum albumin, serum selenium increased by 0.8 μg/l (p < 0.001). Women with an acute phase response also had lower serum selenium (by 5.6 μg/l, p = 0.06).

Conclusion

Serum selenium was independently associated with serum albumin, but not with CD4 count or plasma viral load, in HIV-1-seropositive women. Our findings suggest that associations between lower serum selenium, lower CD4 count, and higher plasma viral load may be related to the frequent occurrence of low serum albumin and the acute phase response among individuals with more advanced HIV-1 infection.
Splenectomy and proximal lieno-renal shunt in a factor five deficient patient with extra-hepatic portal vein obstruction
Authors: Chava Srinivas Prabhu , Pal Sujoy , Ghatak Supriyo , Kumar Rajat , Sahni Peush , Chattopadhyay Tushar Kanti
Published: May 2006

Background

The clinico-surgical implication and successful management of a rare case of factor five (V) deficiency with portal hypertension and hypersplenism due to idiopathic extra-hepatic portal venous obstruction is presented.

Case presentation

A 16-year old boy had gastro-esophageal variceal bleeding, splenomegaly and hypersplenism. During preoperative workup prolonged prothrombin time and activated partial thromboplastin time were detected, which on further evaluation turned out to be due to factor V deficiency. Proximal lieno-renal shunt and splenectomy were successfully performed with transfusion of fresh frozen plasma during and after the surgical procedure. At surgery there was no excessive bleeding. The perioperative course was uneventful and the patient is doing well on follow up.

Conclusion

Surgical portal decompressive procedures can be safely undertaken in clotting factor deficient patients with portal hypertension if meticulous surgical hemostasis is achieved at operation and the deficient factor is adequately replaced in the perioperative period.