bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFICIENT PSEUDOINVERSE LINEAR DISCRIMINANT ANALYSIS AND ITS NONLINEAR FORM FOR FACE RECOGNITION
Authors: LIU JUN , CHEN SONGCAN , TAN XIAOYANG , ZHANG DAOQIANG
Published: January 2008

Pseudoinverse Linear Discriminant Analysis (PLDA) is a classical and pioneer method that deals with the Small Sample Size (SSS) problem in LDA when applied to such applications as face recognition. However, it is expensive in computation and storage due to direct manipulation on extremely large d × d matrices, where d is the dimension of the sample image. As a result, although frequently cited in literature, PLDA is hardly compared in terms of classification performance with the newly proposed methods. In this paper, we propose a new feature extraction method named RSw + LDA, which is (1) much more efficient than PLDA in both computation and storage; and (2) theoretically equivalent to PLDA, meaning that it produces the same projection matrix as PLDA. Further, to make PLDA deal better with data of nonlinear distribution, we propose a Kernel PLDA (KPLDA) method with the well-known kernel trick. Finally, our experimental results on AR face dataset, a challenging dataset with variations in expression, lighting and occlusion, show that PLDA (or RSw + LDA) can achieve significantly higher classification accuracy than the recently proposed Linear Discriminant Analysis via QR decomposition and Discriminant Common Vectors, and KPLDA can yield better classification performance compared to PLDA and Kernel PCA.
FEATURE SELECTION BASED ON MINIMUM ERROR MINIMAX PROBABILITY MACHINE
Authors: XU ZENGLIN , KING IRWIN , LYU MICHAEL R.
Published: January 2008

Feature selection is an important task in pattern recognition. Support Vector Machine (SVM) and Minimax Probability Machine (MPM) have been successfully used as the classification framework for feature selection. However, these paradigms cannot automatically control the balance between prediction accuracy and the number of selected features. In addition, the selected feature subsets are also not stable in different data partitions. Minimum Error Minimax Probability Machine (MEMPM) has been proposed for classification recently. In this paper, we outline MEMPM to select the optimal feature subset with good stability and automatic balance between prediction accuracy and the size of feature subset. The experiments against feature selection with SVM and MPM show the advantages of the proposed MEMPM formulation in stability and automatic balance between the feature subset size and the prediction accuracy.
BIOLOGICALLY MOTIVATED INCREMENTAL OBJECT PERCEPTION BASED ON SELECTIVE ATTENTION
Authors: WON WOONG-JAE , YEO JIYOUNG , BAN SANG-WOO , LEE MINHO
Published: January 2008

In this paper, we propose an object selective attention and perception system, which was implemented by integrating a specific object preferable attention model with an incremental object perception model. The object oriented attention model can selectively pay attention to the candidates of an object in natural scenes based on a bottom-up selective attention model in conjunction with a top-down biased attention mechanism for a specific object. A generative model based on an incremental Bayesian parameter estimation is considered in order to perceive arbitrary objects in the attended areas. Combining an object oriented attention model with general object perception model, the developed system cannot only pay attention to a specific target object but can also memorize the characteristics of task nonspecific objects in an incremental manner. Experimental results show that the developed system generates good performance in successfully focusing on the target objects as well as incrementally perceiving objects in natural scenes.
INVESTIGATION ON MULTISETS MIXTURE LEARNING BASED OBJECT DETECTION
Authors: LIU ZHI-YONG , QIAO HONG , XU LEI
Published: January 2008

By minimizing the mean square reconstruction error, multisets mixture learning (MML) provides a general approach for object detection in image. To calculate each sample reconstruction error, as the object template is represented by a set of contour points, the MML needs to inefficiently enumerate the distances between the sample and all the contour points. In this paper, we develop the line segment approximation (LSA) algorithm to calculate the reconstruction error, which is shown theoretically and experimentally to be more efficient than the enumeration method. It is also experimentally illustrated that the MML based algorithm has a better noise resistance ability than the generalized Hough transform (GHT) based counterpart.
PROJECTIVE NON-NEGATIVE MATRIX FACTORIZATION WITH APPLICATIONS TO FACIAL IMAGE PROCESSING
Authors: YANG ZHIRONG , YUAN ZHIJIAN , LAAKSONEN JORMA
Published: January 2008

We propose a new variant of Non-negative Matrix Factorization (NMF), including its model and two optimization rules. Our method is based on positively constrained projections and is related to the conventional SVD or PCA decomposition. The new model can potentially be applied to image compression and feature extraction problems. Of the latter, we consider processing of facial images, where each image consists of several parts and for each part the observations with different lighting mainly distribute along a straight line through the origin. No regularization terms are required in the objective functions and both suggested optimization rules can easily be implemented by matrix manipulations. The experiments show that the derived base vectors are spatially more localized than those of NMF. In turn, the better part-based representations improve the recognition rate of semantic classes such as the gender or existence of mustache in the facial images.
REPRESENTATION OF 3-D VOLUMETRIC OBJECT FROM THE PANTOMIME EFFECT AND SHADING CUES IN HUMAN BRAIN
Authors: ZHANG QI , MOGI KEN
Published: January 2008

Human ability to process visual information of outside world is yet far ahead of man-made systems in accuracy and speed. In particular, human beings can perceive 3-D object from various cues, such as binocular disparity and monocular shading cues. Understanding of the mechanism of human visual processing will lead to a breakthrough in creating artificial visual systems. Here, we study the human 3-D volumetric object perception that is induced by a visual phenomenon named as the pantomime effect and by the monocular shading cues. We measured human brain activities using fMRI when the subjects were observing the visual stimuli. A coordinated system of brain areas, including those in the prefrontal and parietal cortex, in addition to the occipital visual areas was found to be involved in the volumetric object perception.
FUNDAMENTALS OF THE DEMPSTER-SHAFER THEORY AND ITS APPLICATIONS TO RELIABILITY MODELING
Authors: RAKOWSKY UWE KAY
Published: January 2008

The Dempster-Shafter Theory is well-known for its usefulness to express uncertain judgments of experts. This contribution shows how to apply the calculus to safety and reliability modeling, especially to expert judgment; Failure Modes, Effects, and Criticality Analysis; Event Tree Analysis, Fault Tree Analysis, and Reliability Centered Maintenance. Including a tutorial introduction to the Dempster-Shafer Theory, the differences between the Probability and the Dempster-Shafer Theory are discussed widely.
SYSTEMS RELIABILITY ANALYSIS IN VARIABLE OPERATION CONDITIONS
Authors: SOSZYNSKA JOANNA
Published: January 2008

The semi-markov model of the system operation process is proposed and its selected parameters are defined. There are found reliability and risk characteristics of the multi-state series- "m out of k" system. Next, the joint model of the semi-markov system operation process and the considered multi-state system reliability and risk is constructed. The asymptotic approach to reliability and risk evaluation of this system in its operation process is proposed as well.
VARIABLE-BRANCH TREE-STRUCTURED RESIDUAL VECTOR QUANTIZATION
Authors: YANG SHIUENG-BIEN
Published: January 2008

The traditional tree-structured residual vector quantizers (TSRVQ) are fixed M-ary tree-structured, such that the training samples in each node must be artificially divided into a fixed number of clusters. However, generating the same number of child nodes for each splitting node when the TSRVQ is designed would be inappropriate. This paper presents a genetic splitting (GS) algorithm for designing the tree-structured codebook. The GS algorithm can automatically find the number of child nodes for each splitting node according to the distortion-rate performance. The variable-branch tree-structured residual vector quantizer (VBTSRVQ) based on the GS algorithm is thus proposed. The main disadvantage of VBTSRVQ is that the storage requirements exponentially increase with the number of codewords. However, sharing the codewords in VBTSRVQ can reduce the storage requirements. Thus, this paper also proposes a genetic merge (GM) algorithm to automatically find the similar codewords for merging, and then the storage requirement is reduced in VBTSRVQ. Therefore, this paper proposes VBTSRVQ using a sharing codebook based on the GM algorithm. Also, the distance-rate encoding method is proposed instead of the traditional encoding method for encoding the input sample in VBTSRVQ. VBTSRVQ outperforms other TSRVQs in the experiments presented here.
REGULARITY SCALABLE IMAGE CODING BASED ON WAVELET SINGULARITY DETECTION
Authors: HO CHARLOTTE YUK-FAN , HSUNG TAI-CHIU , LUN DANIEL PAK-KONG , LING BINGO WING-KUEN , TAM PETER KWONG-SHUN , SIU WAN-CHI
Published: January 2008

In this paper, we propose an adaptive algorithm for scalable wavelet image coding, which is based on the general feature, the regularity, of images. In pattern recognition or computer vision, regularity of images is estimated from the oriented wavelet coefficients and quantified by the Lipschitz exponents. To estimate the Lipschitz exponents, evaluating the interscale evolution of the wavelet transform modulus sum (WTMS) over the directional cone of influence was proven to be a better approach than tracing the wavelet transform modulus maxima (WTMM). This is because the irregular sampling nature of the WTMM complicates the reconstruction process. Moreover, examples were found to show that the WTMM representation cannot uniquely characterize a signal. It implies that the reconstruction of signal from its WTMM may not be consistently stable. Furthermore, the WTMM approach requires much more computational effort. Therefore, we use the WTMS approach to estimate the regularity of images from the separable wavelet transformed coefficients. Since we do not concern about the localization issue, we allow the decimation to occur when we evaluate the interscale evolution. After the regularity is estimated, this information is utilized in our proposed adaptive regularity scalable wavelet image coding algorithm. This algorithm can be simply embedded into any wavelet image coders, so it is compatible with the existing scalable coding techniques, such as the resolution scalable and signal-to-noise ratio (SNR) scalable coding techniques, without changing the bitstream format, but provides more scalable levels with higher peak signal-to-noise ratios (PSNRs) and lower bit rates. In comparison to the other feature-based wavelet scalable coding algorithms, the proposed algorithm outperforms them in terms of visual perception, computational complexity and coding efficiency.
ASYMPTOTIC BEHAVIOR OF STRUCTURES MADE OF CURVED RODS
Authors: GRISO GEORGES
Published: January 2008

In this paper, we study the asymptotic behavior of a structure made of curved rods of thickness 2δ when δ tends to 0. This study is carried on within the frame of linear elasticity by using the unfolding method. It is based on several decompositions of the structure displacements and on the passing to the limit in fixed domains.

We show that any displacement of a structure is the sum of an elementary rods-structure displacement (e.r.s.d.) concerning the rods' cross sections and a residual one related to the deformation of the cross section. The e.r.s.d. coincides with rigid body displacements in the junctions. Any e.r.s.d. is given by two functions belonging to [Formula: see text] where [Formula: see text] is the skeleton structure (i.e. the set of rods with middle lines). One of this function [Formula: see text] is the skeleton displacement, the other [Formula: see text] gives the cross section rotation. We show that [Formula: see text] is the sum of an extensional displacement and an inextensional one. We establish a priori estimates and then, we characterize the unfolded limits of the rods-structure displacements.

Eventually, we pass to the limit in the linearized elasticity system and using all results in [6], where on one hand, we obtain a variational problem that is satisfied by the limit extensional displacement, and on the other hand, a variational problem coupling the limit of inextensional displacement and the limit of the rod torsion angles.
A HIGH ACCURACY LERAY-DECONVOLUTION MODEL OF TURBULENCE AND ITS LIMITING BEHAVIOR
Authors: LAYTON WILLIAM , LEWANDOWSKI ROGER
Published: January 2008

In 1934, J. Leray proposed a regularization of the Navier–Stokes equations whose limits were weak solutions of the Navier–Stokes equations. Recently, a modification of the Leray model, called the Leray-alpha model, has attracted interest for turbulent flow simulations. One common drawback of the Leray type regularizations is their low accuracy. Increasing the accuracy of a simulation based on a Leray regularization requires cutting the averaging radius, i.e. remeshing and resolving on finer meshes. This article analyzes on a family of Leray type models of arbitrarily high orders of accuracy for a fixed averaging radius. We establish the basic theory of the entire family including limiting behavior as the averaging radius decreases to zero (a simple extension of results known for the Leray model). We also give a more technically interesting result on the limit as the order of the models increases with a fixed averaging radius. Because of this property, increasing the accuracy of the model is potentially cheaper than decreasing the averaging radius (or meshwidth) and high order models are doubly interesting.
CONTINUITY OF CALDERÓN–ZYGMUND OPERATORS ON BESOV OR TRIEBEL–LIZORKIN SPACES
Authors: MEYER Y. , YANG Q. X.
Published: January 2008

Calderón–Zygmund operators are playing an important role in real analysis. The continuity of Calderón–Zygmund operators T on L2 was studied in [2–4] and, here, we are investigating the continuity of T on the Besov spaces [Formula: see text] where 1 ≤ p, q ≤ ∞ and on the Triebel–Lizorkin spaces [Formula: see text] where 1 ≤ p < ∞, 1 ≤ q ≤ ∞. The exponents measuring the regularity of the distributional kernel K(x, y) of T away from the diagonal are playing a key role in our results. They are smaller than the ones which were assumed by other authors. Moreover, our results are sharp in the case of the Besov spaces [Formula: see text] and of the Triebel–Lizorkin spaces [Formula: see text] when 1 ≤ q ≤ ∞. The proof uses a pseudo-annular decomposition of Calderón–Zygmund operators.
EIGENVALUE PROBLEMS ASSOCIATED WITH NONHOMOGENEOUS DIFFERENTIAL OPERATORS, IN ORLICZ–SOBOLEV SPACES
Authors: MIHĂILESCU MIHAI , RĂDULESCU VICENŢIU
Published: January 2008

We study the boundary value problem - div ((a1(|∇ u|) + a2(|∇ u|))∇ u) = λ|u|q(x)-2u in Ω, u = 0 on ∂Ω, where Ω is a bounded domain in ℝN(N ≥ 3) with smooth boundary, λ is a positive real number, q is a continuous function and a1, a2are two mappings such that a1(|t|)t, a2(|t|)t are increasing homeomorphisms from ℝ to ℝ. We establish the existence of two positive constants λ0and λ1with λ0≤ λ1such that any λ ∈ [λ1, ∞) is an eigenvalue, while any λ ∈ (0, λ0) is not an eigenvalue of the above problem.
Metabolomics: A Global Biochemical Approach to Drug Response and Disease
Authors: Kaddurah-Daouk Rima , Kristal Bruce S. , Weinshilboum Richard M.
Published: January 2008

Metabolomics is the study of metabolism at the global level. This rapidly developing new discipline has important potential implications for pharmacologic science. The concept that metabolic state is representative of the overall physiologic status of the organism lies at the heart of metabolomics. Metabolomic studies capture global biochemical events by assaying thousands of small molecules in cells, tissues, organs, or biological fluids—followed by the application of informatic techniques to define metabolomic signatures. Metabolomic studies can lead to enhanced understanding of disease mechanisms and to new diagnostic markers as well as enhanced understanding of mechanisms for drug or xenobiotic effect and increased ability to predict individual variation in drug response phenotypes (pharmacometabolomics). This review outlines the conceptual basis for metabolomics as well as analytical and informatic techniques used to study the metabolome and to define metabolomic signatures. It also highlights potential metabolomic applications to pharmacology and clinical pharmacology.
Stimulation of both type I and type II corticosteroid receptors blunts counterregulatory responses to subsequent hypoglycemia in healthy man
Authors: Gustavson Stephanie M. , Sandoval Darleen A. , Ertl Andrew C. , Bao Shichun , Raj Satish R. , Davis Stephen N.
Published: January 2008

Antecedent increases of corticosteroids can blunt counterregulatory responses to subsequent stress. Our aim was to determine whether prior activation of type I corticosteroid (mineralocorticoid) or type II corticosteroid (glucocorticoid) receptors blunts counterregulatory responses to subsequent hypoglycemia. Healthy volunteers participated in five randomized 2-day protocols. Day 1 involved morning and afternoon 2-h hyperinsulinemic (9 pmol·kg−1·min−1) euglycemic clamps (PE; n = 14), hypoglycemic clamps (PH; n = 14), or euglycemic clamps with oral fludrocortisone (PE + F; type I agonist, 0.2 mg, n = 14), oral dexamethasone (PE + D; type II agonist, 0.75 mg, n = 13), or both (PE + F + D; n = 14). Day 2 was identical in all protocols and consisted of a 2-h hyperinsulinemic hypoglycemic clamp. Day 2 insulin (625 ± 40 pmol/l) and glucose (2.9 ± 0.1 mmol/l) levels were similar among groups. Levels of epinephrine, norepinephrine, glucagon, growth hormone, and MSNA were significantly blunted by prior activation of both type I and type II corticosteroid receptors to PE. Prior activation of both corticosteroid receptors also significantly blunted NEFA during subsequent hypoglycemia. Thus, levels of a wide spectrum of key counterregulatory mechanisms (neuroendocrine, ANS, and metabolic) were blunted by antecedent pharmacological stimulation of either type I or type II corticosteroid receptors in healthy man. These data suggest that activation of type I corticosteroid receptors in man can have acute and profound regulating effects on physiological stress in man. Both type I and type II corticosteroid receptors may be involved in the multiple mechanisms controlling counterregulatory responses to hypoglycemia in healthy man.
Erg K+ channels modulate contractile activity in the bovine epididymal duct
Authors: Mewe Marco , Wulfsen Iris , Schuster Anna M. E. , Middendorff Ralf , Glassmeier Günter , Schwarz Jürgen R. , Bauer Christiane K.
Published: January 2008

The expression and functional role of ether-à-go-go-related gene (erg) K+ channels were examined in the bovine epididymal duct. Sperm transit through the epididymal duct relies on spontaneous phasic contractions (SC) of the peritubular smooth muscle wall. Isometric tension studies revealed SC-enhancing effects of the erg channel blockers E-4031, dofetilide, cisapride, and haloperidol and SC-suppressing effects of the activator NS-1643. In the corpus epididymidis, EC50 values of 32 nM and 8.3 μM were determined for E-4031 and NS-1643, respectively. E-4031 was also able to elicit contraction in epithelium-denuded corpus segments, which lacked SC. In the cauda region, E-4031 and NS-1643 exerted effects on agonist-induced contraction similar to those observed in the proximal duct. Experiments with nifedipine and thapsigargin suggested that the excitatory effects of E-4031 depended mainly on external calcium influx and not on intracellular calcium release. Western blot and RT-PCR assays revealed the expression of both, erg1a and erg1b, in all duct regions. Because erg1b appears to predominate in the epididymal duct, patch-clamp experiments were performed on heterologously expressed erg1b channels to investigate the sensitivity of this splice variant to NS-1643. In contrast to its effects on erg1a, NS-1643 induced a concentration-dependent current increase mainly due to a marked leftward shift in erg1b channel activation by ∼30 mV at 10 μM, explaining the inhibitory effect of the drug on epididymal SC. In summary, these data provide strong evidence for a physiological role of erg1 channels in regulating epididymal motility patterns.
Pituitary adenylate cyclase-activating polypeptide maintains neonatal breathing but not metabolism during mild reductions in ambient temperature
Authors: Cummings Kevin J. , Willie Chris , Wilson Richard J. A.
Published: January 2008

Mild reductions in ambient temperature dramatically increase the mortality of neonatal mice deficient in pituitary adenylate cyclase-activating polypeptide (PACAP), with the majority of animals succumbing in the second postnatal week. During anesthesia-induced hypothermia, PACAP−/− mice at this age are also vulnerable to prolonged apneas and sudden death. From these observations, we hypothesized that before the onset of genotype-specific mortality and in the absence of anesthetic, the breathing of PACAP-deficient mice is more susceptible to mild reductions in ambient temperature than wild-type littermates. To test this hypothesis, we recorded breathing in one group of postnatal day 4 PACAP+/+, +/−, and −/− neonates (using unrestrained, flow-through plethysmography) and metabolic rate in a separate group (using indirect calorimetry), both of which were exposed acutely to ambient temperatures slightly below (29°C), slightly above (36°C), or at thermoneutrality (32°C). At 32°C, the breathing frequency of PACAP−/− neonates was significantly less than PACAP+/+ littermates. Reducing the ambient temperature to 29°C caused a significant suppression of tidal volume and ventilation in both PACAP+/− and −/− animals, while the tidal volume and ventilation of PACAP+/+ animals remained unchanged. Genotype had no effect on the ventilatory responses to ambient warming. At all three ambient temperatures, genotype had no influence on oxygen consumption or body temperature. These results suggest that during mild reductions in ambient temperature, PACAP is vital for the preservation of neonatal tidal volume and ventilation, but not for metabolic rate or body temperature.
Encoding Network States by Striatal Cell Assemblies
Authors: Carrillo-Reid Luis , Tecuapetla Fatuel , Tapia Dagoberto , Hernández-Cruz Arturo , Galarraga Elvira , Drucker-Colin René , Bargas José
Published: January 2008

Correlated activity in cortico-basal ganglia circuits plays a key role in the encoding of movement, associative learning and procedural memory. How correlated activity is assembled by striatal microcircuits is not understood. Calcium imaging of striatal neuronal populations, with single-cell resolution, reveals sporadic and asynchronous activity under control conditions. However, N-methyl-d-aspartate (NMDA) application induces bistability and correlated activity in striatal neurons. Widespread neurons within the field of observation present burst firing. Sets of neurons exhibit episodes of recurrent and synchronized bursting. Dimensionality reduction of network dynamics reveals functional states defined by cell assemblies that alternate their activity and display spatiotemporal pattern generation. Recurrent synchronous activity travels from one cell assembly to the other often returning to the original assembly; suggesting a robust structure. An initial search into the factors that sustain correlated activity of neuronal assemblies showed a critical dependence on both intrinsic and synaptic mechanisms: blockage of fast glutamatergic transmission annihilates all correlated firing, whereas blockage of GABAergic transmission locked the network into a single dominant state that eliminates assembly diversity. Reduction of L-type Ca2+-current restrains synchronization. Each cell assembly comprised different cells, but a small set of neurons was shared by different assemblies. A great proportion of the shared neurons was local interneurons with pacemaking properties. The network dynamics set into action by NMDA in the striatal network may reveal important properties of striatal microcircuits under normal and pathological conditions.
Sexually Transmitted Infections, Sexual Risk Behaviors and the Risk of Heterosexual Spread of HIV among and beyond IDUs in St. Petersburg, Russia
Authors: Abdala N. , Krasnoselskikh T.V. , Durante A.J. , Timofeeva M.Y. , Verevochkin S.V. , Kozlov A.P.
Published: January 2008

Aims: This study investigates whether sexual transmitted behaviors and infections (STIs) among injection drug users (IDUs) may promote the spread of HIV among and beyond IDUs in Russia. Methods: We conducted a cross-sectional survey of behavior and tested for STIs in a convenience sample of 159 IDUs in St. Petersburg, Russia. Results: The median age was 27 and 57% were male. Almost all were sexually active, half had casual partners and 40% reported ≧2 sex partners in the previous 3 months. Of those who answered, 81% reported sex without condoms, 44% reported having sex with at least one partner who was not an IDU. Of 139 (87%) subjects who were actively injecting, 29% reported receptive syringe sharing. Twenty percent of subjects were seropositive for HIV-1 and 42% of HIV-1-negative subjects tested positive for an STI. Conclusions: The sample exhibited high levels of sexual risk behaviors and STIs, and a large proportion had sexual partners who were not IDUs. This population requires comprehensive interventions that ensures access to condoms and sterile injection supplies and that encourage safer sexual behaviors in an attempt to keep sexual transmission of HIV low.
Socioeconomic Differences in Alcohol-Specific Parenting Practices and Adolescents’ Drinking Patterns
Authors: Spijkerman Renske , van den Eijnden Regina J.J.M. , Huiberts Annemarie
Published: January 2008

The aim of this study was to investigate to what extent alcohol-specific parenting practices relate to adolescents’ alcohol use, binge drinking, and alcohol-related problems, and whether these associations are moderated by socioeconomic status (SES), i.e. parents’ education level and family income. The present data were collected within the framework of a representative study on alcohol use among Dutch students. The present findings are based on data from respondents who had been drinking in the past year (81.5%), and of whom one of the parents had filled out a short questionnaire including SES characteristics (52%). The sample consisted of 1,344 adolescents. Adolescents were approached in a school setting; parents received a short questionnaire at the home address. The results show that applying strict rules about alcohol use and having qualitative good conversations about drinking alcohol seem to prevent adolescents from heavy drinking patterns, whereas parental alcohol use seems to promote adolescents’ drinking. A positive association was found between frequency of alcohol communication and availability of alcohol at home on the one hand and adolescents’ drinking on the other. Some moderating effects of SES were found.
Association of Personality Disorders, Family Conflicts and Treatment with Quality of Life in Opiate Addiction
Authors: Karow A. , Verthein U. , Krausz M. , Schäfer I.
Published: January 2008

Aim: The purpose of this study was to investigate the association of the current status and longitudinal changes in different clinical and social variables with quality of life (QOL) in opiate addiction. Our hypotheses were that drug use, comorbid personality disorders and social problems are associated with worse QOL. Methods: 107 participants with long-term opiate addiction were included and interviewed at entry with the Europ-ASI and the PDQ-R. QOL (SF-36) and changes in different domains of the Europ-ASI were assessed after 2 years. Results: Personality disorders, interpersonal conflicts with the family or partner and ongoing need for somatic and psychiatric treatment were significantly associated with worse subjective QOL, whereas changes in drug and alcohol use, the economic situation, legal problems and social problems with persons outside of the family showed no relevant association with QOL. Conclusion: Our results provide support for an emphasis in treatment on helping clients to reduce intra- and interpersonal conflicts according to comorbid conditions and among family members and partnerships. In addition, the present data provide further support for the advantages of extended interventions in long-term opiate addiction.
Pathophysiology of Salt-Sensitive Hypertension: A New Scope of an Old Problem
Authors: Franco Martha , Sanchez-Lozada Laura G. , Bautista Rocio , Johnson Richard J. , Rodriguez-Iturbe Bernardo
Published: January 2008

It has been recognized for many years that salt intake is one of the main environmental factors responsible for the development of hypertension. More than 30 years ago, Guyton and co-workers postulated a relationship between blood pressure and natriuresis which maintains sodium balance and extracellular volume; thus an impaired ability of the kidney to excrete sodium requires an increase in blood pressure to increase natriuresis and correct the sodium balance, resulting in hypertension. Currently, the mechanisms responsible for the alterations mentioned above remain under investigation. Among them, microvascular and tubulointerstitial injury induce salt retention and development of salt-sensitive hypertension that appears to be mediated in part by lymphocytes and macrophages infiltrating the tubulointerstitium that produce angiotensin II and stimulate oxidative stress. In the post-angiotensin salt-sensitive hypertension model, angiotensin levels are elevated despite systemic angiotensin II levels being suppressed, and the local angiotensin II levels correlate with the presence of intrarenal inflammation and cortical vasoconstriction. Under these conditions, blockade of the angiotensin II AT1 receptors ameliorate cortical vasoconstriction. Thus, the renal angiotensin system in association with interstitial immune infiltrating cells may play a pivotal role in the development and maintenance of salt-sensitive hypertension.
How Common Is Malnutrition in ESRD? New Approaches to Diagnosis of Malnutrition
Authors: Kuhlmann Martin K. , Levin Nathan W.
Published: January 2008

Malnutrition is associated with increased mortality in the dialysis population. However, the true prevalence of malnutrition is not known due to the lack of simple diagnostic strategies for assessing nutritional status. Internationally recommended diagnostic algorithms mainly include the one-time assessment of nutritional indices and comparison to normal reference values. However, these indices do not take into account the dynamics of malnutrition which is associated with a progressive change in body composition and loss in muscle mass. Longitudinal assessment of changes in body composition may be necessary to improve timing and accuracy of the diagnosis of undernutrition. Whole-body as well as segmental multifrequency bioimpedance spectroscopy have been shown to yield good estimates of total body or segmental (limb) muscle mass. Bioimpedance spectroscopy is a relatively inexpensive, non-invasive, painless method requiring only minimal operator training, which in the near future may prove useful for nutritional management of ESRD patients.
Negative Outcome Studies in End-Stage Renal Disease
Authors: Goldsmith David
Published: January 2008

The mortality rates which we have seen now over several decades of routine provision of renal replacement therapy are truly remarkable – even if, with time, we have become familiar, if not comfortable, with them. The remarkable nature of this mortality issue is its severity, and persistence, despite numerous efforts to combat it with ‘active interventions’. These have included, in no particular order, correction of anaemia, better provision of dialysis adequacy, use of more permeable dialysis membranes, better control of dyslipidaemia, better control of mineral and bone metabolic parameters, correction of hyperhomocysteinaemia, and use of ACE inhibitors. One can now in 2008 be forgiven for some pessimism, nihilism (sometimes known as ‘renalism’) about the prospects for useful prolongation of life on dialysis except of course by transplantation. In this article (a fuller version of which appears also in Nephrology Dialysis and Transplantation, I discuss the reasons for the failure of the trials to date, the likely obstacles to future trials succeeding, and some suggestions for alternative strategies to try to grapple with this immense burden of vascular and all-cause morbidity and mortality.
Practice Guidelines Do Improve Patient Outcomes: Association or Causation?
Authors: Levin A.
Published: January 2008

Guidelines have been developed in nephrology and medicine developed to assist practitioners and patients in making decisions about healthcare for specific clinical circumstances. There has been a proliferation of guidelines over the last decade in all areas of medicine, including nephrology. Many of the nephrology guidelines are based on a less robust evidentiary base than guidelines in cardiology or diabetes. There continues to be a debate in medicine as to whether guidelines and their development process actually impact patient outcomes. This article describes the ways in which guidelines may impact patient outcomes in nephrology and emphasizes the role of guidelines in education, research and health policy development such that there is an indirect benefit on medical practice and thus patient outcomes. Our failure to be able to directly attribute any specific guideline to a change in patient outcomes speaks to the complexity of CKD patients, and the difficult in measuring hard outcomes versus process outcomes. Examples of the activities stimulated by guidelines in key areas of nephrology are given. Guidelines are an important component of the application of medical knowledge to medical practice, and need to be contextualized as such. Rigorous evaluation of current implementation techniques and resultant impacts should be undertaken.
Uremic Toxins: Do We Know Enough to Explain Uremia?
Authors: Vanholder R. , Meert N. , Schepers E. , Glorieux G.
Published: January 2008

Background: The uremic syndrome is characterized by a complex clinical picture, whereby the function of multiple organ systems is affected by the retention of a host of solutes. Recent research of the last decade has helped to unravel multiple pathophysiologic mechanisms and to identify as yet unknown responsible compounds. Methods: The literature was screened to appreciate which compounds play the most important pathophysiologic role. Results: The picture that ensues is that the main role is played by molecules which are so-called ‘difficult to remove by dialysis’. The knowledge of uremic toxicity is still far from complete and we need extra information about responsible compounds and mechanisms, eventually leading to a classification of the most important culprits, to allow the development of efficient removal strategies and of pharmacologic methods to counteract pathophysiologic mechanisms. Conclusions: Uremic retention is a complex phenomenon and the most toxic compounds are difficult to remove by dialysis. Furthermore, our knowledge of the responsible pathways is still incomplete, and needs to be extended to develop new and more efficient treatment strategies.
Water-Free Na+ Retention: Interaction with Hypertension and Tissue Hydration
Authors: Titze Jens
Published: January 2008

Electrolyte and body fluid homeostasis in higher vertebrates is believed to be fully understood. The paradigm is that Na+ is restricted mainly to the extracellular fluid and K+ to the intracellular space, where both ions act to hold water and thereby control the extracellular and intracellular fluid volume by their osmotic activity. Na+ accumulation thus inevitably leads to water retention. The constancy of the extracellular volume is the task of the kidneys, which control the total body Na+ content. More recent data from balance studies in humans have questioned this traditional view, suggesting that large amounts of Na+ can be accumulated without accompanying water retention by osmotically inactive Na+ retention, or by osmotically neutral Na+/K+ exchange. Besides the control of the body Na+ content by the kidneys, redistribution of body electrolytes hence provides an extrarenal regulatory alternative in the maintenance of body fluid volume and blood pressure control.
The MPO Study: Just a European HEMO Study or Something Very Different?
Authors: Locatelli Francesco , Gauly Adelheid , Czekalski Stanislaw , Hannedouche Thierry , Jacobson Stefan H. , Loureiro Alfredo , Martin-Malo Alejandro , Papadimitriou Menelaos , Passlick-Deetjen Jutta , Ronco Claudio , Vanholder Raymond , Wizemann Volker
Published: January 2008

Although results from observational and epidemiological studies suggested a survival benefit associated with high-flux hemodialysis, conclusive evidence from prospective randomized clinical trials has been lacking. Both the HEMO Study in the USA and the Membrane Permeability Outcome Study (MPO Study) in Europe are randomized studies investigating the effect of high- and low-flux hemodialysis on patient outcomes, even though there were some significant differences in the design of the two studies. An earlier randomized clinical trial could not show differences on patient survival between patient groups being treated with membranes of different material and permeability, but this trial was not designed specifically to examine this particular endpoint. Based on these previous experiences, the MPO Study addressed a hemodialysis patient population which was considered to be more susceptible to the intervention with high-flux dialysis. To identify these patients with an elevated risk, low serum albumin levels were chosen as an indicator; low serum albumin is associated with malnutrition, inflammation, atherosclerosis, and with increased risk of morbidity and mortality. Together with low serum albumin, patients had to be new to dialysis to be selected for the MPO Study. These particular considerations on patient selection, together with additional methodological refinements in the study design allow the conclusion that the MPO Study is valid on its own rather than being a European version of the HEMO Study.
Cross-Sectional Fat Area at the Forearm in Children and Adolescents
Authors: Fricke Oliver , Sumnik Zdenek , Remer Thomas , Stabrey Angelika , Tutlewski Baerbel , Schoenau Eckhard
Published: January 2008

Background: Cross-sectional fat area (FA) and muscle area have been recently used to describe local body composition at the forearm in children and adolescents. The present analysis intends to characterize FA in a normal collective. Methods: FA was measured by peripheral quantitative computed tomography in a study collective (DONALD study) of 296 children and adolescents. FA was analyzed in relation to fat mass (FM) measured by 4 skinfold thicknesses. Results: FA was significantly correlated with FM (r = 0.8). FA was positively associated with height in prepubertal individuals and pubertal females, but negatively associated with height in pubertal males. Median and range of FA are displayed for different height ranges and pubertal stages in males and females to enable analyses of FA in subgroups. Conclusion: Because of the positive dependence of FA on height in prepubertal individuals and pubertal females, reference values of FA may be based on height. But reference values in pubertal males or in a mixed pubertal population should be rather based on pubertal stages than on height.
The Views of Young Adults and Their Parents on Hormone Treatment for Short Stature in Adolescence
Authors: Visser-van Balen Hanneke , Geenen Rinie , Looij Janneke , Huisman Jaap , Wit Jan M. , Sinnema Gerben
Published: January 2008

Aim: To examine the view of young adults and their parents on growth hormone (GH) and gonadotropin-releasing hormone agonist (GnRHa) treatment in adolescence for idiopathic short stature (ISS) or short stature born small for gestational age (SGA). Methods: Thirty young adults with ISS or SGA (18 treated, 12 untreated; age 17–23 years; 5.5 years after treatment) completed questionnaires and they and their parents were interviewed. Results: Self-perceived current psychosocial functioning did not differ between the treated and untreated young adults, but several treated participants perceived psychosocial problems during adolescence. Most treated participants would have chosen again to receive hormone treatment, but they mentioned disadvantages of the treatment and were, as well as untreated participants, reticent upon recommending hormone treatment to others. Conclusion: GH/GnRHa treatment did not appear to have adverse long-term psychosocial consequences and the participants were glad to have taken the opportunity to receive hormone treatment. However, the treated group mentioned several disadvantages of the treatment and perceived some height-related psychosocial problems during adolescence. In considering hormone treatment, the positive as well as the negative aspects of the treatment as perceived by the participants are to be taken into consideration.
Primary Hyperparathyroidism in Neonates and Childhood
Authors: Mallet Eric
Published: January 2008

Objectives: Primary hyperparathyroidism (HP1) in childhood is thought to be extremely rare. Its exact incidence remains unknown, as do the characteristics of HP1. A retrospective study collection was conducted on cases supplied by members of the Working Group on Calcium Metabolism throughout France over a 20-year period (1984–2004), since the availability of the intact parathormone (iPTH) radioimmunoassay. Results: 55 cases were collected of which 11 were neonates. Among the 44 children and adolescents, there were 18 male and 26 female patients, ranging in age from 6 to 18 (mean 13) years. 83% were symptomatic and 43% had nephrolithiasis. Symptoms were associated with high serum calcium and inappropriate iPTH levels. Ultrasonography and technetium-labelled methoxyisobutylisonitrile scintigraphy are useful tools for the preoperative localization of adenomas, particularly in adolescents. Intraoperative iPTH assays are effective in minimizing invasive parathyroidectomy. All patients, except neonates, underwent surgery: 29 adenomas and 11 hyperplasias were found. Two multiple endocrine neoplasias (MENs) were subsequently discovered. Since the calcium-sensing receptor (CaSR) mutation was reported, the form of management in neonates has become more medical (intravenous diphosphonates) than surgical. On follow-up no recurrence was observed except for MEN. Conclusion: These national results reflect HP1 epidemiology. HP1 is a rare entity and appears to be a severe disease in terms of symptoms with regard to management. The use of molecular biology tests could be useful not only in neonatal cases (CaSR mutation) but also prior to surgery in children (MEN mutation).
Telangiectasia as a Presenting Sign of Graves’ Disease
Authors: Casadio Rachele , Santi Valentina , Mirici-Cappa Federica , Magini Giulia , Cacciari Mauro , Bernardi Mauro , Trevisani Franco
Published: January 2008

Acquired nevoid telangiectasia (ANT) is observed in several conditions including primary cutaneous disorders, systemic autoimmune disease and hyperestrogenism occurring in puberty, pregnancy and chronic liver disease. We describe a patient in whom ANT was a presenting sign of autoimmune hyperthyroidism, which improved after thyroidectomy. A 43-year-old Caucasian woman experienced an asymptomatic development of multiple widespread red skin lesions, diagnosed to be ANT. Blood tests revealed increased serum levels of free tri-iodothyronine and thyroxine and suppressed thyroid-stimulating hormone. Other causes of ANT were excluded. ANT improved but did not disappear after thyroidectomy. The possible pathogenetic factors linking ANT and Graves’ disease, such as an immune-mediated process, altered estrogen metabolism or vasodilatation associated with hyperdynamic circulation, are discussed.
Basal Cell Carcinomas and Actinic Keratoses Seen in Dermatological Practice in France: A Cross-Sectional Survey
Authors: Bernard P. , Dupuy A. , Sasco A. , Brun P. , Duru G. , Nicoloyannis N. , Grob J.-J.
Published: January 2008

Background: Most actinic keratoses (AKs) and a number of basal cell carcinomas (BCCs) cannot be assessed by pathological records. Objective: To estimate prospectively the figures and characteristics of BCCs and AKs seen by French dermatologists, their medical load, and present a more realistic approach to their incidence. Methods: A cross-sectional study conducted in France in a representative sample of dermatologists (n = 215). Out-patients seen for 1 or more BCCs or AKs were recorded over 4 non-consecutive weeks. Results: Among 78,300 out-patients, 1,321 had 1 (or more) BCC, and 3,688 had 1 or more AKs (1 and 5% of consultations made by dermatologists). When extrapolating, the medical load in France was estimated at 248,000 and 693,000 consultations/year leading to a clinical diagnosis of BCC and AK, respectively. A total of 1,655 BCCs were diagnosed including 839 superficial (50.7%), 636 nodular (38.4%), 137 morpheiform (8.3%) and 43 other types (2.6%). Superficial and nodular BCCs were more frequently diagnosed with a small size (<10 mm) than morpheiform BCCs. Conclusion: Our study in France provides the first estimate of the clinical burden represented by AKs and BCCs in dermatology practice.
Heterogeneity of Circulating CD4+ Memory T-Cell Subsets in Erythrodermic Patients: CD27 Analysis Can Help to Distinguish Cutaneous T-Cell Lymphomas from Inflammatory Erythroderma
Authors: Fierro M.T. , Novelli M. , Quaglino P. , Comessatti A. , Fava P. , Ortoncelli M. , Ponti R. , Bernengo M.G.
Published: January 2008

Background: Chronic dermatoses, as well as Sézary syndrome (SS), the erythrodermic and leukaemic cutaneous T-cell lymphoma, display a T-cell memory pattern. Recent findings suggest that different memory T-cell subsets can be recognized based on CD27 and CD45RO/RA expression. No data are reported as to CD27 expression in SS. Objectives: To evaluate different memory T-cell subsets, i.e. central memory (TCM), effector memory (TEM) and terminally differentiated cells in SS and inflammatory erythroderma (IE). Materials and Methods: Forty SS and 137 IE patients were included. CD27 and CD45RO/CD45RA expression was analysed by flow cytometry on peripheral blood lymphocytes and immunohistochemistry.Results: A significantly higher expression of the CD4+CD27+CD45RA– TCM subset was observed in SS whilst IE patients were characterized by increased CD4+CD27–CD45RA– TEM levels. The Vβ-restricted population was homogeneously CD4+CD26–CD27+ in the SS subjects. Conclusions: SS and IE are characterized by a different memory T-cell subset expression; CD27 expression could be used as an additional diagnostic tool in the differential diagnosis.
Generalized Xerotic Dermatitis with Neutrophilic Spongiosis Induced by Erlotinib (Tarceva®)
Authors: Lübbe J. , Masouyé I. , Dietrich P.-Y.
Published: January 2008

Erlotinib is a small molecule tyrosine kinase inhibitor that is used as an anticancer agent. Most patients develop a pustular facial dermatitis within the first week of treatment. Pyogenic granulomas of the nail folds are another typical adverse event occurring in about 10–15% of cases. We report on a patient who developed a generalized dermatitis characterized by neutrophilic spongiosis. Neutrophilic inflammation has been observed in several drugs that interfere with EGFR signaling, suggesting a class effect. The present case may be yet another manifestation of this particular reaction pattern.