bluuebunny/crossref_metadata_2025 huggingface dataset:
Rowing, the ultimate challenge to the human body – implications for physiological variables
Authors: Volianitis Stefanos , Secher Niels H.
Published: April 2009

Clinical diagnoses depend on a variety of physiological variables but the full range of these variables is seldom known. With the load placed on the human body during competitive rowing, the physiological range for several variables is illustrated. The extreme work produced during rowing is explained by the seated position and the associated ability to increase venous return and, thus, cardiac output. This review highlights experimental work on Olympic rowing that presents a unique challenge to the human capacities, including cerebral metabolism, to unprecedented limits, and provides a unique opportunity to reveal the extreme range of many physiological variables.
Measuring the contribution of community members to functional diversity
Authors: Schmera Dénes , Podani János , Erős Tibor
Published: April 2009

Although the contribution of community members to functional diversity is a key question of conservation ecology, its measurement and interpretation are rather problematic. In this paper, we suggest a novel method for decomposing functional diversity. To do this we consider functional units (i.e. species or a group of species with identical traits) as the functional building blocks of communities. Then we propose the use of a recently developed measure of functional diversity (called modified functional attribute diversity or MFAD) and suggest additive decomposition of MFAD into functional values contributed by the functional units. We point out that functional values are related to changes in MFAD if the functional unit is removed from the community. This property of decomposition allows the quantification of the contribution of community members to functional diversity. By studying artificial and actual communities we compare the performance of our new method with other recently developed contribution measures, which are based on dendrograms and ordinations. Both theoretical considerations and analyses of artificial and actual data sets suggest that the proposed method of calculating functional values expresses more explicitly the contribution of community members to functional diversity and hereby can be used as a simple, yet efficient method for searching for functional keystones in ecological communities or for quantifying the contribution of community members to functional diversity.
Almost Normal: Experiences of Adolescents With Implantable Cardioverter Defibrillators
Authors: Zeigler Vicki L. , Nelms Tommie
Published: April 2009

PURPOSE. The purpose of this study was to describe the experiences of adolescents with implantable cardioverter defibrillators (ICDs).

DESIGN AND METHODS. This qualitative study explored the lived experiences of 14 adolescents with ICDs using face‐to‐face, semistructured interviews.

RESULTS. Six themes were identified: life interrupted; still the same, except; sometimes it's tough; it cuts both ways; unique joule; and living life regular.

PRACTICE IMPLICATIONS. These findings suggest that nurses could make a significant impact on the lives of adolescents with ICDs by focusing their efforts away from viewing the adolescent through an illness lens and more toward a normalization lens.
COMPRESSING BEHAVIOR AND TEXTURE EVALUATION FOR POTATOES PRETREATED BY PULSED ELECTRIC FIELD
Authors: GRIMI NABIL , LEBOVKA NIKOLAÏ , VOROBIEV EUGENE , VAXELAIRE JEAN
Published: April 2009

The objective of this study was to investigate the effects of pulsed electric field (PEF) treatment on compressing behavior and texture of potatoes. Textural data reveal that PEF treatment can cause enlargement of pressure for the same level of deformation. The fracture pressures Pc were approximately the same for both untreated and PEF‐treated specimens, Pc ≈ 4.5 ± 0.4 MPa. The maximal pressure Pm, at which the time of the pressure‐induced rupture of intact cells should be of the same order of magnitude as the time of fluid expression from damaged cells, was estimated as Pm ≈ 6 MPa. For a small pressure (P = 1 MPa) to obtain a similar deformation (ε = 0.15) requires pressing time t ≈ 3.5 h for untreated tissue and t ≈ 70 s for PEF‐treated tissue. Measured electrical conductivity was practically constant and exhibited no noticeable time dependence during constant pressure stage in untreated samples, while the conductivity of PEF‐treated specimens decreases in the course of pressing.

PRACTICAL APPLICATIONS

Solid–liquid expression is widely used in the food industry for the extraction of fruit and vegetables. Efficiency of this process can be increased by different pretreatment methods. Pulsed electric field (PEF) has been shown to be good for juice yield intensification and for improving the product quality in juice production. It is of great interest for process purposes to study texture proprieties of PEF‐treated and untreated tissues, because texture is one of the most important quality attributes of food products. This work also gives new information about the mechanism of the PEF‐induced damage and expression from tissues. The obtained results may be helpful for development of new engineering concepts based on PEF‐enhanced extraction at comparatively low pressures and moderate time of processing.
Low genetic diversity and high genetic differentiation in the critically endangeredOmphalogramma souliei(Primulaceae): implications for its conservation
Authors: HUANG Yuan , ZHANG Chang‐Qin , LI De‐Zhu
Published: April 2009

Omphalogramma soulieiFranch. is an endangered perennial herb only distributed in alpine areas of SW China. ISSR markers were applied to determine the genetic variation and genetic structure of 60 individuals of three populations ofO. soulieiin NW Yunnan, China. The genetic diversity at the species level is low withP=42.5% (percentage of polymorphic bands) andHsp=0.1762 (total genetic diversity). However, a high level of genetic differentiation among populations was detected based on different measures (Nei's genetic diversity analysis:Gst=0.6038; AMOVA analysis:Fst=0.6797). Low level of genetic diversity within populations and significant genetic differentiation among populations might be due to the mixed mating system in which xenogamy predominated and autogamy played an assistant role inO. souliei.The genetic drift due to small population size and limited current gene flow also resulted in significant genetic differentiation. The assessment of genetic variation and differentiation of the endangered species provides important information for conservation on a genetic basis. Conservation strategies for this rare endemic species are proposed.
Dielectric thickness dependence of capacitive behavior in graphene deposited on silicon dioxide
Authors: Sonde S. , Giannazzo F. , Raineri V. , Rimini E.
Published: April 2009

Scanning capacitance microscopy (SCM) is used to probe on nanoscale the capacitive behavior of graphene deposited on a SiO2∕Si n+ substrate (with SiO2 thickness of 300 or 100nm). The SCM tip provides the contact on graphene, while the Si n+ substrate acts as the backgate contact in the graphene/SiO2∕Si capacitor. The authors studied the screening by the graphene two-dimensional electron gas on the modulating potential applied between the backgate and the SCM tip. In particular, they determined the effect of the oxide thickness on the lateral distribution (i.e., screening length) and the density of the screening charge in graphene. Experimental results indicate that thinner oxide leads to higher screening charge density in the graphene sheet and to higher effectively biased area on graphene. This correspondingly increases the total capacitance (Ctot) of the graphene/SiO2∕Si capacitor. We evaluated the dependence on the dielectric thickness of the classical metal-oxide-semiconductor (MOS) capacitance (CMOS) and of the quantum capacitance (Cq) contributions to Ctot.
Evidence for Cardiomyocyte Renewal in Humans
Authors: Bergmann Olaf , Bhardwaj Ratan D. , Bernard Samuel , Zdunek Sofia , Barnabé-Heider Fanie , Walsh Stuart , Zupicich Joel , Alkass Kanar , Buchholz Bruce A. , Druid Henrik , Jovinge Stefan , Frisén Jonas
Published: April 2009

It has been difficult to establish whether we are limited to the heart muscle cells we are born with or if cardiomyocytes are generated also later in life. We have taken advantage of the integration of carbon-14, generated by nuclear bomb tests during the Cold War, into DNA to establish the age of cardiomyocytes in humans. We report that cardiomyocytes renew, with a gradual decrease from 1% turning over annually at the age of 25 to 0.45% at the age of 75. Fewer than 50% of cardiomyocytes are exchanged during a normal life span. The capacity to generate cardiomyocytes in the adult human heart suggests that it may be rational to work toward the development of therapeutic strategies aimed at stimulating this process in cardiac pathologies.
Widespread Changes in Synaptic Markers as a Function of Sleep and Wakefulness in
Drosophila
Authors: Gilestro Giorgio F. , Tononi Giulio , Cirelli Chiara
Published: April 2009

Sleep is universal, strictly regulated, and necessary for cognition. Why this is so remains a mystery, although recent work suggests that sleep, memory, and plasticity are linked. However, little is known about how wakefulness and sleep affect synapses. Using Western blots and confocal microscopy in
Drosophila
, we found that protein levels of key components of central synapses were high after waking and low after sleep. These changes were related to behavioral state rather than time of day and occurred in all major areas of the
Drosophila
brain. The decrease of synaptic markers during sleep was progressive, and sleep was necessary for their decline. Thus, sleep may be involved in maintaining synaptic homeostasis altered by waking activities.
Conditional Mutagenesis in
Drosophila
Authors: Choi Ching Man , Vilain Sven , Langen Marion , Van Kelst Sofie , De Geest Natalie , Yan Jiekun , Verstreken Patrik , Hassan Bassem A.
Published: April 2009

Most genes function at multiple stages of metazoan development, in dividing and nondividing cells. Generating mouse conditional knock-outs (cKO), where a gene can be eliminated in a temporally and spatially controlled manner, is a valuable technique because it allows study of gene function at any stage of life. In contrast and despite the development of many other powerful genetic tools, cKO has thus far been lacking in
Drosophila
. We combined several recent molecular and genetic technical advances in an approach termed integrase-mediated approach for gene knock-out (IMAGO). IMAGO allows the replacement of any genomic sequence, such as a gene, with another desired sequence, including cKO alleles that can be used to create positively marked mutant cells. IMAGO should also be applicable to other genetic model organisms.
Iron-Based Catalysts with Improved Oxygen Reduction Activity in Polymer Electrolyte Fuel Cells
Authors: Lefèvre Michel , Proietti Eric , Jaouen Frédéric , Dodelet Jean-Pol
Published: April 2009

Iron-based catalysts for the oxygen-reduction reaction in polymer electrolyte membrane fuel cells have been poorly competitive with platinum catalysts, in part because they have a comparatively low number of active sites per unit volume. We produced microporous carbon–supported iron-based catalysts with active sites believed to contain iron cations coordinated by pyridinic nitrogen functionalities in the interstices of graphitic sheets within the micropores. We found that the greatest increase in site density was obtained when a mixture of carbon support, phenanthroline, and ferrous acetate was ball-milled and then pyrolyzed twice, first in argon, then in ammonia. The current density of a cathode made with the best iron-based electrocatalyst reported here can equal that of a platinum-based cathode with a loading of 0.4 milligram of platinum per square centimeter at a cell voltage of ≥0.9 volt.
Outbreak of Hepatitis E Virus Infection in Darfur, Sudan: Effectiveness of Real-Time Reverse Transcription-PCR Analysis of Dried Blood Spots
Authors: Mérens Audrey , Guérin Philippe Jean , Guthmann Jean-Paul , Nicand Elisabeth
Published: April 2009

Biological samples collected in refugee camps during an outbreak of hepatitis E were used to compare the accuracy of hepatitis E virus RNA amplification by real-time reverse transcription-PCR (RT-PCR) for sera and dried blood spots (concordance of 90.6%). Biological profiles (RT-PCR and serology) of asymptomatic individuals were also analyzed.
Adeno-Associated Virus Replication Induces a DNA Damage Response Coordinated by DNA-Dependent Protein Kinase
Authors: Schwartz Rachel A. , Carson Christian T. , Schuberth Christine , Weitzman Matthew D.
Published: April 2009

The parvovirus adeno-associated virus (AAV) contains a small single-stranded DNA genome with inverted terminal repeats that form hairpin structures. In order to propagate, AAV relies on the cellular replication machinery together with functions supplied by coinfecting helper viruses such as adenovirus (Ad). Here, we examined the host cell response to AAV replication in the context of Ad or Ad helper proteins. We show that AAV and Ad coinfection activates a DNA damage response (DDR) that is distinct from that seen during Ad or AAV infection alone. The DDR was also triggered when AAV replicated in the presence of minimal Ad helper proteins. We detected autophosphorylation of the kinases ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and signaling to downstream targets SMC1, Chk1, Chk2, H2AX, and XRCC4 and multiple sites on RPA32. The Mre11 complex was not required for activation of the DDR to AAV infection. Additionally, we found that DNA-PKcs was the primary mediator of damage signaling in response to AAV replication. Immunofluorescence revealed that some activated damage proteins were found in a pan-nuclear pattern (phosphorylated ATM, SMC1, and H2AX), while others such as DNA-PK components (DNA-PKcs, Ku70, and Ku86) and RPA32 accumulated at AAV replication centers. Although expression of the large viral Rep proteins contributed to some damage signaling, we observed that the full response required replication of the AAV genome. Our results demonstrate that AAV replication in the presence of Ad helper functions elicits a unique damage response controlled by DNA-PK.
Salt-resistant blood pressure and salt-sensitive renal autoregulation in chronic streptozotocin diabetes
Authors: Lau Catherine , Sudbury Ian , Thomson Michael , Howard Perry L. , Magil Alex B. , Cupples William A.
Published: April 2009

Hyperfiltration occurs in early type 1 diabetes mellitus in both rats and humans. It results from afferent vasodilation and thus may impair stabilization of glomerular capillary pressure by autoregulation. It is inversely related to dietary salt intake, the “salt paradox.” Restoration of normal glomerular filtration rate (GFR) involves increased preglomerular resistance, probably mediated by tubuloglomerular feedback (TGF). To begin to test whether the salt paradox has pathogenic significance, we compared intact vs. diabetic (streptozotocin) Long-Evans rats with normal and increased salt intake, 1 and ∼3% by weight of food eaten, respectively. Weekly 24-h blood pressure records were acquired by telemetry before and during diabetes. Blood glucose was maintained at ∼20 mmol/l by insulin implants. GFR was significantly elevated only in diabetic rats on normal salt intake, confirming diabetic hyperfiltration and the salt paradox. Renal blood flow dynamics show strong contributions to autoregulation by both TGF and the myogenic mechanism and were not impaired by diabetes or by increased salt intake. Separately, systolic pressure was not elevated in diabetic rats at any time during 12 wk with normal or high salt intake. Autoregulation was effective in all groups, and the diabetic-normal salt group showed significantly improved autoregulation at low perfusion pressures. Histological examination revealed very minor glomerulosclerosis and modest mesangial expansion, although neither was diagnostic of diabetes. Periodic acid-Schiff-positive droplets found in distal tubules and collecting duct segments were diagnostic of diabetic kidneys. Biologically significant effects attributable to increased salt intake were abrogation of hyperfiltration and of the left shift in autoregulation in diabetic rats.
Segregated and Integrated Coding of Reward and Punishment in the Cingulate Cortex
Authors: Fujiwara Juri , Tobler Philippe N. , Taira Masato , Iijima Toshio , Tsutsui Ken-Ichiro
Published: April 2009

Reward and punishment have opposite affective value but are both processed by the cingulate cortex. However, it is unclear whether the positive and negative affective values of monetary reward and punishment are processed by separate or common subregions of the cingulate cortex. We performed a functional magnetic resonance imaging study using a free-choice task and compared cingulate activations for different levels of monetary gain and loss. Gain-specific activation (increasing activation for increasing gain, but no activation change in relation to loss) occurred mainly in the anterior part of the anterior cingulate and in the posterior cingulate cortex. Conversely, loss-specific activation (increasing activation for increasing loss, but no activation change in relation to gain) occurred between these areas, in the middle and posterior part of the anterior cingulate. Integrated coding of gain and loss (increasing activation throughout the full range, from biggest loss to biggest gain) occurred in the dorsal part of the anterior cingulate, at the border with the medial prefrontal cortex. Finally, unspecific activation increases to both gains and losses (increasing activation to increasing gains and increasing losses, possibly reflecting attention) occurred in dorsal and middle regions of the cingulate cortex. Together, these results suggest separate and common coding of monetary reward and punishment in distinct subregions of the cingulate cortex. Further meta-analysis suggested that the presently found reward- and punishment-specific areas overlapped with those processing positive and negative emotions, respectively.
Alcoholism: A Systems Approach From Molecular Physiology to Addictive Behavior
Authors: Spanagel Rainer
Published: April 2009

Alcohol consumption is an integral part of daily life in many societies. The benefits associated with the production, sale, and use of alcoholic beverages come at an enormous cost to these societies. The World Health Organization ranks alcohol as one of the primary causes of the global burden of disease in industrialized countries. Alcohol-related diseases, especially alcoholism, are the result of cumulative responses to alcohol exposure, the genetic make-up of an individual, and the environmental perturbations over time. This complex gene × environment interaction, which has to be seen in a life-span perspective, leads to a large heterogeneity among alcohol-dependent patients, in terms of both the symptom dimensions and the severity of this disorder. Therefore, a reductionistic approach is not very practical if a better understanding of the pathological processes leading to an addictive behavior is to be achieved. Instead, a systems-oriented perspective in which the interactions and dynamics of all endogenous and environmental factors involved are centrally integrated, will lead to further progress in alcohol research. This review adheres to a systems biology perspective such that the interaction of alcohol with primary and secondary targets within the brain is described in relation to the behavioral consequences. As a result of the interaction of alcohol with these targets, alterations in gene expression and synaptic plasticity take place that lead to long-lasting alteration in neuronal network activity. As a subsequent consequence, alcohol-seeking responses ensue that can finally lead via complex environmental interactions to an addictive behavior.
Mechanisms of Cancer Cachexia
Authors: Tisdale Michael J.
Published: April 2009

Up to 50% of cancer patients suffer from a progressive atrophy of adipose tissue and skeletal muscle, called cachexia, resulting in weight loss, a reduced quality of life, and a shortened survival time. Anorexia often accompanies cachexia, but appears not to be responsible for the tissue loss, particularly lean body mass. An increased resting energy expenditure is seen, possibly arising from an increased thermogenesis in skeletal muscle due to an increased expression of uncoupling protein, and increased operation of the Cori cycle. Loss of adipose tissue is due to an increased lipolysis by tumor or host products. Loss of skeletal muscle in cachexia results from a depression in protein synthesis combined with an increase in protein degradation. The increase in protein degradation may include both increased activity of the ubiquitin-proteasome pathway and lysosomes. The decrease in protein synthesis is due to a reduced level of the initiation factor 4F, decreased elongation, and decreased binding of methionyl-tRNA to the 40S ribosomal subunit through increased phosphorylation of eIF2 on the α-subunit by activation of the dsRNA-dependent protein kinase, which also increases expression of the ubiquitin-proteasome pathway through activation of NFκB. Tumor factors such as proteolysis-inducing factor and host factors such as tumor necrosis factor-α, angiotensin II, and glucocorticoids can all induce muscle atrophy. Knowledge of the mechanisms of tissue destruction in cachexia should improve methods of treatment.
Recanalization and Reperfusion Therapies for Acute Ischemic Stroke
Authors: Molina Carlos A. , Alvarez-Sabín José
Published: April 2009

Arterial recanalization and subsequent reperfusion have extensively demonstrated the ability to restore the brain function when performed shortly after acute ischemic stroke. Experimental and human studies have consistently demonstrated that early tissue reperfusion may limit ischemic tissue enlargement, leading to a reduced infarct size and favorable clinical outcome. However, arterial recanalization does not necessarily lead to brain tissue reperfusion. Lack of reperfusion after early recanalization may be caused by multiple downstream embolization, blockage of microcirculation due to non-reflow phenomenon or rapid recruitment of ischemic tissue before recanalization resulting in non-nutritional reperfusion. In some cases, sudden tissue reperfusion may be deleterious, leading to brain blood barrier disruption and hemorrhagic transformation or massive brain edema due to the so-called ‘reperfusion injury’. In spite of this, recanalization represents the powerful predictor of stroke outcome and it is being increasingly used as a surrogate efficacy measurement in thrombolytic and other revascularization trials in acute stroke. Several emerging strategies have the potential to extend cerebral reperfusion therapy to larger numbers of patients, including patients presenting beyond the current 3-hour time window. Moreover, novel reperfusion approaches may improve the efficacy and safety of thrombolysis in a larger number of stroke patients. This review highlights recent advances in reperfusion treatments for acute ischemic stroke.
MAMLD1 (CXorf6): A New Gene Involved in Hypospadias
Authors: Ogata Tsutomu , Laporte Jocelyn , Fukami Maki
Published: April 2009

MAMLD1 (mastermind-like domain containing 1), previously known as CXorf6 (chromosome X open reading frame 6), has been shown to be a causative gene for hypospadias. This is primarily based on the identification of nonsense mutations (E124X, Q197X, and R653X), which undergo nonsense-mediated mRNA decay, in patients with penoscrotal hypospadias. Subsequent studies have shown that (1) the mouse homolog is transiently expressed in fetal Sertoli and Leydig cells around the critical period of sex development; (2) transient knockdown of Mamld1 results in significantly reduced testosterone production in murine Leydig tumor cells; (3) MAMLD1 protein shares homology to mastermind-like 2 (MAML2) protein that functions as a co-activator in canonical Notch signaling; (4) MAMLD1 localizes to the nuclear bodies and transactivates the promoter activity of a non-canonical Notch target gene hairy/enhancer of split 3 (Hes3), rather than the canonical Notch target genes such as Hes1 and Hes5, without demonstrable DNA-binding capacity, and (5) MAMLD1 is regulated by steroidogenic factor 1. These findings suggest that the MAMLD1 mutations cause hypospadias primarily because of compromised testosterone production around the critical period of sex development, and provide useful information for the molecular network involved in fetal testosterone production.
Differential Impact of Apathy and Depression in the Development of Dementia in Mild Cognitive Impairment Patients
Authors: Vicini Chilovi Barbara , Conti Marta , Zanetti Marina , Mazzù Ilenia , Rozzini Luca , Padovani Alessandro
Published: April 2009

Background and Aims: Neuropsychiatric symptoms may accompany mild cognitive impairment (MCI) and assist in identifying incipient dementia. The aim of this study was to evaluate the role of apathy and depression in the conversion to dementia among MCI subjects. Methods: 124 MCI outpatients were investigated. Diagnosis of apathy and depression was based on clinical criteria. The main endpoint was the development of dementia within 2 years from the enrolment. Results: 50 (40.3%) subjects were classified as MCI normal, 38 (30.7%) as MCI depressed, 21 (16.9%) as MCI depressed-apathetic and 15 (12.1%) as apathetic. The rates of conversion were 24% for MCI normal, 7.9% for MCI depressed, 19% for MCI depressed-apathetic and 60% for MCI apathetic. Diagnosis of apathy was a risk factor for conversion apart from age, functional and cognitive status at baseline (OR = 7.07; 95% CI 1.9–25.1; p = 0.003). In contrast, MCI depressed subjectshad a reduced risk of conversion (OR = 0.10; 95% CI 0.02–0.4; p = 0.001). Conclusion: These findings argue for a differential role of apathy and depression in the development of dementia, and suggest the need of dissecting in MCI patients apathy and depression symptoms in the reading of mood disorders.
Enantiomer-Specific Effects of Albuterol on Airway Inflammation in Healthy and Asthmatic Cats
Authors: Reinero Carol R. , Delgado Cherlene , Spinka Christine , DeClue Amy E. , Dhand Rajiv
Published: April 2009

Background: Racemic (R,S)-albuterol is a 1:1 mixture of an R-enantiomer which has bronchodilatory and anti-inflammatory effects, and an S-enantiomer which is associated with increased airway hyperreactivity and proinflammatory effects. Proinflammatory effects of regularly inhalated and S-albuterol have not been studied in a whole-animal model. We hypothesized that regular administration of R,S-albuterol or S-albuterol, but not R-albuterol, would induce airway inflammation in healthy and asthmatic cats. Methods: Six healthy and 5 experimentally asthmatic cats were randomized to receive inhaled R,S-albuterol, S-albuterol, R-albuterol, or placebo (saline) twice daily for 2 weeks, followed by a 6-week washout before crossover to the next treatment. Bronchoalveolar lavage fluid was collected for cell counts and cytokine analysis prior to and at the end of each 2-week treatment. Results: Healthy and asthmatic cats receiving R,S- and S-albuterol had higher total lavage cell numbers (p = 0.04 and p = 0.02, respectively) than those receiving R-albuterol and placebo. The number of lavage eosinophils and the TNF-α bioactivity was higher in asthmatic cats receiving R,S- and S-albuterol compared with those receiving the other treatments (p = 0.03 and p = 0.004, respectively). In healthy cats, the number of lavage neutrophils was higher when they received R,S- and S-albuterol compared with other treatments (p = 0.04). Conclusion: Airway inflammation is induced in both healthy and asthmatic cats with regular inhalation of racemic and S-albuterol, but not with R-albuterol.
Specific IgE and IgG Responses and Cytokine Profile in Subjects with Allergic Reactions to Biting Midge Forcipomyia taiwana
Authors: Chen Yi-Hsing , Lee Mey-Fann , Tsai Jaw-Ji , Wu Hsin-Ju , Hwang Guang-Yuh
Published: April 2009

Background:Forcipomyia taiwana is a tiny blood-sucking midge whose habitat covers large parts of Taiwan and southern China. Female midges bite during the day, causing intense pruritis and swelling in allergic individuals. In this study, we investigated the immune responses of different allergic reactions to midge bites. Methods:F. taiwana (midge)-specific IgE, -IgG and -IgG subclasses were examined by ELISA in 62 human subjects. Peripheral blood mononuclear cells (PBMC) from 6 subjects with solely delayed reactions (SDR) to midge bites and 6 nonallergic controls (NAC) were cultured with midge extract at various time points and assayed. Proliferation of PBMC was measured by MTT assay. Expression of cytokine mRNA was measured by real-time PCR and protein levels by cytometric bead immunoassay or ELISA. Protease activity in midge extract was determined by the Azocoll method. Results: Midge-specific IgE among subjects with an immediate reaction were significantly elevated compared to SDR and NAC subjects. There were no differences in the level of midge-specific-IgG, -IgG1, -IgG2, -IgG3 and -IgG4 among subjects with different biting reactions. Midge extract elicited significantly more PBMC proliferation, higher expression of IFN-γ, IL-10, IL-6 and TNF-α in SDR subjects than in NAC. Protease activity was detected in midge extract. Protease inhibitors E64 and pepstatin suppressed midge-extract-induced IL-8 production. Conclusions: Our results suggest that an immediate reaction to midge bites is IgE-mediated. IFN-γ, IL-6 and TNF-α are involved in delayed reactions to midge bites. A protease-activated pathway may also be involved in the intense, itchy reactions to midge bites.
Decreased Connexin 43 and Increased Fibrosis in Atrial Regions Susceptible to Complex Fractionated Atrial Electrograms
Authors: Liu Xu , Shi Hai-feng , Tan Hong-wei , Wang Xin-hua , Zhou Li , Gu Jia-ning
Published: April 2009

Background and Objectives: Complex fractionated atrial electrograms (CFAE) is distributed at preferential sites of atrium, and the mechanism underlying CFAE is not fully understood. We hypothesized that preexisting atrial abnormalities may be involved in the formation of CFAE. Methods: Twelve pigs were subjected to acetylcholine infusion and right atrial pacing to induce sustained atrial fibrillation. The shortest complex interval map was used to visualize CFAE on three-dimensional anatomic structure of left atrium, and the CFAE sites were labeled by ablation. The expression of connexin 43 (Cx43) and myocardial fibrosis were examined. Results: The expression of Cx43 at CFAE sites was significantly decreased when compared with non-CFAE sites, while myocardial fibrosis was enhanced in CFAE sites compared with non-CFAE sites. Conclusions: These results suggested that the decreased expression of Cx43 and enhanced myocardial fibrosis at CFAE sites of the left atrium may be the structure abnormalities underlying CFAE.
Multiple Imputation to Correct for Measurement Error in Admixture Estimates in Genetic Structured Association Testing
Authors: Padilla Miguel A. , Divers Jasmin , Vaughan Laura K. , Allison David B. , Tiwari Hemant K.
Published: April 2009

Objectives: Structured association tests (SAT), like any statistical model, assumes that all variables are measured without error. Measurement error can bias parameter estimates and confound residual variance in linear models. It has been shown that admixture estimates can be contaminated with measurement error causing SAT models to suffer from the same afflictions. Multiple imputation (MI) is presented as a viable tool for correcting measurement error problems in SAT linear models with emphasis on correcting measurement error contaminated admixture estimates. Methods: Several MI methods are presented and compared, via simulation, in terms of controlling Type I error rates for both non-additive and additive genotype coding. Results: Results indicate that MI using the Rubin or Cole method can be used to correct for measurement error in admixture estimates in SAT linear models. Conclusion: Although MI can be used to correct for admixture measurement error in SAT linear models, the data should be of reasonable quality, in terms of marker informativeness, because the method uses the existing data to borrow information in which to make the measurement error corrections. If the data are of poor quality there is little information to borrow to make measurement error corrections.
The Skin as an Organ for the Study of the Pharmacology of Neuropeptides
Authors: Foreman J.C.
Published: April 2009

There is good evidence that some vascular effects of inflammation in the skin are neurogenic and involve axon reflexes in the terminal arborizations of C-fibres containing substance P, neurokinin A and calcitonin gene-related peptide (CGRP). Substance P produces dose-related wheal and flare reactions in human skin. Neurokinin A induces wheal but little or no flare and is less potent than substance P. CGRP induces both wheal and flare but is also less potent than substance P. In addition, CGRP induces a slow-onset, intense vasodilatation in human skin which persists for several hours and is associated with leucocyte infiltration: a response which is not seen with substance P. Substance P also releases histamine from mast cells in the skin and the presence or absence of a role for histamine and mast cells in neurogenic inflammation in skin is discussed.
Role of Free Radicals in the Mode of Action of Anthralin
Authors: Lambelet P. , Löliger J. , Shroot B.
Published: April 2009

Radical reactions of anthralin and its metabolites with skin have been studied by ESR spectroscopy. The influence of compounds which are known to suppress inflammation are described. The ESR spectra recorded during the reaction of anthralin with skin were essentially composed of one broad line centered at g = 2.0030. Similar but much weaker spectra were recorded with the dimer and no signal at all was obtained with 9, 10-dihy-droxyanthraquinone. The ESR response obtained with anthralin was neither affected by the radical scavengers 2-tert-butyl-4-methoxy-phenol (BHA), 2,6-di-tert-butyl-4-methyl-phenol (BHT) dl-Α-tocopherol, nor by the antiinflammatory agents clobetasol-17-propionate or indomethacin, nor by potassium hydroxide. We infer that anthralin inflammation is not associated with the presence of anthralin-derived radicals in the skin.
Cytochrome-P-450-Dependent Metabolism of Retinoic Acid in Rat Skin Microsomes: Inhibition by Ketoconazole
Authors: Vanden Bossche Hugo , Willemsens Gustaaf , Janssen Paul A.J.
Published: April 2009

Epidermal microsomes, prepared from neonatal Wistar or Sprague-Dawley rats, show low levels of retinoic acid (RA) metabolism. The specific activities (as fmol/min/mg protein) of epidermal microsomes, using [15–14C]-RA as substrate, are 232 (Wistar rats) and 222 (Sprague-Dawley rats). Topical application of RA (1 mg) on 4-day-old rats induces a 3.3-and 3.9-fold increase in epidermis microsomal RA metabolism. A 4.6- to 8.1-fold increase is observed 24 h after topical application of 3-methylcholanthrene (0.5 mg). By contrast, phenobarbital (1 mg topically) has a much smaller inducing effect. So far the chemical structure of the metabolites has not been identified. The Rf values of two major compounds correspond with those of 4-hydroxy- and 4-ketoretinoic acid, formed after incubation of hamster liver microsomes in the presence of [15–14C]-RA. The RA metabolism in rat epidermal micromes shows the typical characteristics of a cytochrome-P-450 (P450)-dependent enzyme system, i.e. a requirement for NADPH and oxygen and inhibition by CO and SKF-525A. Ketoconazole and miconazole, imidazole antifungal agents and inhibitors of some fungal and mammalian P450-dependent enzymes, inhibit in vitro RA metabolism by rat epidermal microsomes. 50% inhibition is achieved at 6.5 × 10-7 and ≧ 10-5 mol/l, respectively. The triazole antifungal agent, itraconazole, has no effect at concentrations up to 10-5 mol/l. Topical treatment of 4-day-old Wistar rats with ketoconazole, at doses of 1, 5 and 10 mg/kg, 1 h before the application of RA (1 mg/rat) results in a dose-dependent inhibition of RA metabolism by epidermal microsomes, prepared 24 h later. Our data show a P450-dependent RA metabolism in rat epidermal microsomes and suggest that ketoconazole may prove to be effective in maintaining biologically active levels of RA in epidermal cells.
Cis-trans Intelconversion of Acitretin in Man
Authors: Geiger J.-M. , Brindley C.J.
Published: April 2009

The major plasma metabolite of acitretin (trans-acitretin) is its 13-cis isomer, cis-acitretin. Interconversion of cis -acitretin to trans-acitretin was demonstrated in man following administration of a single oral dose of cis -acitretin. Plasma concentrations of Ro 13–7652 (cis-acitretin) and Ro 10–1670 (trans-acitretin) were much higher after cis -acitretin administration than after trans-acitretin administration. Surprisingly, these high concentrations were not associated with a clear therapeutic effect in dermatoses (e.g. psoriasis) which are usually responsive to oral retinoids. Interactions between the cis and trans isomers formed in vivo may explain the difference in therapeutic activity of each stereoisomer when administered orally.
Bioassays for Retinoic Acid-Like Substances Using Cultured Human Keratinocytes
Authors: Regnier M. , Eustache J. , Shroot B. , Darmon M.
Published: April 2009

Using cultured human keratinocytes, three bioassays for retinoic acid-like substances have been developed. They are based on the ability of these substances (1) to inhibit cross-linked envelope formation, (2) to inhibit the synthesis of the Kl keratin, and (3) to stimulate the synthesis of the K19 keratin. The data, expressed as 50% inhibitory or activating concentrations were used to rank compounds according to their activity.
UVB-Induced Pigmentation in Hairless Mice as an in vivo Assay for Topical Skin-Depigmenting Activity
Authors: Nair Xina , Tramposch Kenneth M.
Published: April 2009

Several reports have demonstrated that exposure to ultraviolet light elicits increased pigmentation in the skin of the Skh:HR2 mouse. We have reexamined this model to assess its potential as a screen for compounds with skin-depigmenting activity. The application of the previously reported ultraviolet light-B (UVB) doses led to marked necrotic damage to the skin which greatly diminished the usefulness of the model for drug testing. We have modified this model by exposing the mice to a progressively increasing dose of UVB that promotes pigmentation with a marked reduction of skin irritation. Furthermore, for compound evaluation, we preselected only those mice which developed signs of increased pigmentation after the first week of UVB exposure. This was critical for any meaningful compound evaluation, since only about 50% of the mice eventually showed signs of increased pigmentation with UVB. Our modifications make it possible to use this model for evaluating new compounds with skin-depigmenting activity. The validity of this method has been examined with a number of compounds including hydroquinone, 4-hydroxyanisole, kojic acid and all-trans retinoic acid, all with known depigmenting activity.
Culture of Human Sebocytes and Markers of Sebocytic Differentiation in vitro
Authors: Zouboulis Christos C. , Xia Longqing , Detmar Michael , Bogdanoff Birgit , Giannakopoulos Georgios , Gollnick Harald , Orfanos Constantin E.
Published: April 2009

Human sebocytes obtained as explants after in vitro culture of isolated sebaceous glands were recently shown to maintain in part a sebocytic differentiation. The aim of this study was to further identify markers of sebocytic differentiation in vitro. Therefore, the morphology of cultured human sebocytes, and their differentiation with lipid storing and expression of cellular proteins were investigated by microscopy, electron microscopy, study of cell kinetics, cytochemistry and immunocytochemistry, and were compared to cultured human keratinocytes obtained from the same skin specimens. At first, sebocytes in all stages of sebocytic differentiation were detected in vitro. Abundant cytoplasmic lipids and the absence of desmosomes were identified as their ultrastructural characteristics. Secondly, an increasing number of sebocytes storing lipids was detected during cell proliferation. Sebocytes contained up to 4 times more lipids than keratinocytes in vitro. Squalene and increased quantities of wax/sterol esters could be extracted from secondary sebocyte cultures. Thirdly, the monoclonal antibodies 6B10 (keratin 4), RPN1162 (keratin 7), and OM-1 labeled only sebocytes in vitro. Furthermore, sebocytes presented a marked expression of keratin 19 in comparison to keratinocytes, as detected with CK 4.62, and a lack of RPN1161 (keratins 1 and 2) expression, which was typically found to be expressed in cultured keratinocytes. The culture of human sebocytes possessing several characteristics of sebocytic differentiation in vivo offers unique possibilities in investigating direct effects on sebaceous cell growth, differentiation and their regulation.
Ciclopiroxolamine Cream 1%: In vitro and in vivo Penetration into the Stratum corneum
Authors: Ceschin-Roques C.G. , Hänel H. , Pruja-Bougaret S.M. , Lagarde I. , Vandermander J. , Michel G.
Published: April 2009

Studies were conducted to assess the penetration of 1 % ciclopiroxolamine cream, establishing the concentrations of the antimycotic compound in different layers of the stratum corneum with two skin models. Results of in vitro studies using skin from domestic pigs indicate that ciclopiroxolamine has the ability to penetrate fast into the epidermis, by inhibiting and killing inoculated Trichophyton mentagrophytes. In vivo investigation of the stratum corneum has been performed in healthy human volunteers by 20 strippings collected in four layers. Fungicidal concentrations of ciclopiroxolamine were determined after extraction from the strippings. These studies demonstrate that the concentrations reached levels which are sufficient to inhibit and kill pathogenic fungi.
Acitretin Decreases Tumor Cell-Induced Angiogenesis
Authors: Rudnicka Lidia , Marczak Maria , Szmurło Andrzej , Makieła Barbara , Skiendzielewska Anna , Skopinska Magdalena , Majewski Sławomir , Jabłonska Stefania
Published: April 2009

The effects of acitretin and etretinate on angiogenesis induced in Balb/c mice by intradermal injection of keratinocyte tumor cell lines were evaluated. It was shown that both retinoids are capable of inhibiting angiogenesis evoked by a human epidermoid carcinoma cell line (A431). Acitretin, but not etretinate, inhibited also angiogenesis induced by the spontaneously transformed murine keratinocyte cell line Pam 212 and by the established tumorigenic SKv cell line harboring the HPV16 genome. We suggest that inhibition of blood vessel formation may be one of the mechanisms responsible for the anticancerogenic effect of retinoids.
In vitro Generation of Smooth Muscle-Contracting Leukotrienes from Isolated Epidermal Cells
Authors: Möller Annelie , Grabbe Jürgen , Rosenbach Thomas , Wilhelms Otto-Henning , Czarnetzki Beate M.
Published: April 2009

Single-cell suspensions of murine and human epidermal cells were studied for the presence of peptidoleukotrienes (LTs), using in vitro guinea pig ileum contraction as bioassay and a commercial radioimmunoassay. The calcium ionophore A23187 at 5 × 10-6M alone or in combination with arachidonic acid at 10-4M caused release of LTC4/D4 within 10–30 min and for up to 18 h. LTB4, as was measured in the chemotaxis assay, was released at different levels and with different kinetics from the same cells. Epidermal cells may thus regulate cutaneous inflammation by secreting potent vasoactive and muscle-contracting in addition to chemotactic lipid mediators.
The Effect of Platinum Complexes on Human Skin Cells in vivo and in vitro
Authors: Featherstone J. , Dykes P.J. , Marks R.
Published: April 2009

The effects of platinum complexes on human fibroblasts and keratinocytes have been investigated. Cytotoxic effects were observed at approximately 4 µM (cisplatin), 10 µM (carboplatin) and 15 µM (JM9) when cells were grown continuously in these agents. When applied topically to hairless mouse skin in vitro carboplatin was shown to penetrate the skin and give levels where a cytotoxic effect would be apparent. Using an in vivo model of epidermal hyperproliferation in the mouse, an antimitotic effect of a 1 % and 5 % topical carboplatin preparation was demonstrated. These results suggest that topical platinum complexes are of potential in the therapy of hyperproliferative skin diseases.
Xanthines Inhibit 3T3 Fibroblast Proliferation
Authors: Levi-Schaffer Francesca , Touitou Elka
Published: April 2009

It is believed that xanthines can inhibit cell proliferation by elevating intracellular cAMP. Therefore, these compounds can be useful in hyperprohferative disorders. Our aim was to assess the efficacy of theophylline, caffeine and dyphylline on 3T3 fibroblast proliferation. 3T3 subconfluent cultures were incubated for 3 days with the xanthine derivatives (1 mM-1μM). At 1 and 0.1 mM the three derivatives exhibited marked inhibition of fibroblast proliferation. Theophylline and caffeine were more potent than dyphylline. At a concentration of 1 mM, the three xanthine derivatives also inhibited proliferation of psoriatic dermal fibroblast, albeit to a lower extent. Caffeine was the most active compound followed by theophylline and dyphylline. We conclude that xanthine derivatives are good candidates for use as fibroblast antiproliferative drugs. We also conclude that 3T3 fibroblasts appear to be a valid system for the pharmacological screening of fibroblast antiproliferative drugs.
Serotonin Initiation of Delayed-Type Hypersensitivity: Mediation by a Primitive Thy-1+ Antigen-Specific Clone or by Specific Monoclonal IgE Antibody
Authors: Askenase Philip W. , Herzog Wulf R. , Millet Isabelle , Paliwal Vipin , Ramabhadran Rajani , Rochester Carolyn , Geba Gregory P. , Ptak Wlodzimierz
Published: April 2009

Elicitation of delayed-type hypersensitivity (DTH) responses is due to the required sequential action of two different antigen (Ag)-specific Thy-1+ cells: early acting, DTH-initiating cells and locally recruited CD4+, ΑΒ-TCR+, DTH effector T cells. DTH-initiating cells have an unusual phenotype for Ag-specific cells (Thy-1+, CD5+, CD4-, CD8-, CD3-, slg-, B220+ (CD45RA+), Mac 1+, IL-2R- and IL-3R+) and act by producing Ag-specific non-IgE factors that sensitize mast cells for release of the vasoactive amine serotonin (5HT) at the local site of elicitation of DTH by challenge. Another mechanism of DTH initiation involves Ag-specific IgE antibodies that also can sensitize mast cells for local serotonin release. Serotonin initiates DTH by activating the local endothelial cells to allow recruitment of DTH effector T cells, and also by activating 5HT-2 receptors on these recruited T cells.