bluuebunny/crossref_metadata_2025 huggingface dataset:
The PREFIB Study: PREvention of Atrial FIBrillation by Rapid Atrial Pacing. Preliminary Results
Authors: Flammang D. , Loteanu V. , Hamani D. , Lambiez M. , Flammang‐Dorie. G.
Published: December 2004

Background: Previous studies have compared various atrial pacing rates and pacing sites for preventing atrial fibrillation (AF) recurrences, defined by symptoms or by channels markers and/or by mode switching counters. Counters and markers reliability has never been proven especially in case of muscular noise. New pacemakers provide EGMs storage allowing to optimize the detection of arrhythmia recurrences. Study design: The PREFIB study was designed to assess the time recurrence of AF on two different DDD pacing rates. Thirty patients (pts) with symptomatic recurrent AF or brady‐tachycardia syndromes have been implanted with a Guidant Pulsar 1280 pacemaker. In all pts, the atrial lead was positioned in the right atrial appendage. After a 5‐days observation period, the DDD pacing rate was randomly programmed at 60 (+ a 15 bpm hysteresis) or at 80 bpm for 12 weeks. Both programmings were crossed over at the end of this fixed period or when symptomatic AF recurred. Antiarrhythmic drug therapy was continued after implantation. AF recurrence was diagnosed by stored EGMs and confirmed by an external loop recorder. Results: Twenty two pts (12 males, 78 ± 7.1 years old) have already completed the study protocol. One pt withdrew for severe heart failure when paced at 80 bpm. For the 21 pts, AF recurred in 12 pts paced at 60 (−15) bpm, after a mean time of 28 days (range 1–64), and in 7 pts paced at 80 bpm, after a mean time of 47 days (range 4–79). Even if this difference is not statistically significant, these results indicate a beneficial trend for faster pacing rates. AF recurrence was asymptomatic in 43% of pts. Conclusion: These preliminary results confirm 1) the beneficial trend of rapid atrial pacing for preventing AF recurrence; 2) the utility of reliable stored EGMs for AF therapeutic management; 3) the need for increasing the EGMs memory size embodied in pacemakers.
Bioengineered ‘golden’ indica rice cultivars with β‐carotene metabolism in the endosperm with hygromycin and mannose selection systems
Authors: Datta Karabi , Baisakh Niranjan , Oliva Norman , Torrizo Lina , Abrigo Editha , Tan Jing , Rai Mayank , Rehana Sayda , Al‐Babili Salim , Beyer Peter , Potrykus Ingo , Datta Swapan K.
Published: December 2004

Vitamin‐A deficiency (VAD) is a major malnutrition problem in South Asia, where indica rice is the staple food. Indica‐type rice varieties feed more than 2 billion people. Hence, we introduced a combination of transgenes using the biolistic system of transformation enabling biosynthesis of provitamin A in the endosperm of several indica rice cultivars adapted to diverse ecosystems of different countries. The rice seed‐specific glutelin promoter (Gt‐1 P) was used to drive the expression of phytoene synthase (psy), while lycopene β‐cyclase (lcy) and phytoene desaturase (crtI), fused to the transit peptide sequence of the pea‐Rubisco small subunit, were driven by the constitutive cauliflower mosaic virus promoter (CaMV35S P). Transgenic plants were recovered through selection with either CaMV35S P driven hph (hygromycin phosphotransferase) gene or cestrum yellow leaf curling virus promoter (CMP) driven pmi (phophomannose isomerase) gene. Molecular and biochemical analyses demonstrated stable integration and expression of the transgenes. The yellow colour of the polished rice grain evidenced the carotenoid accumulation in the endosperm. The colour intensity correlated with the estimated carotenoid content by spectrophotometric and HPLC analysis. Carotenoid level in cooked polished seeds was comparable (with minor loss of xanthophylls) to that in non‐cooked seeds of the same transgenic line. The variable segregation pattern in T1 selfing generation indicated single to multiple loci insertion of the transgenes in the genome. This is the first report of using nonantibiotic pmi driven by a novel promoter in generating transgenic indica rice for possible future use in human nutrition.
Enrichment of cereal protein lysine content by altered tRNAlys coding during protein synthesis
Authors: Wu Xing Rong , Chen Zhi Hong , Folk William R.
Published: December 2004

The world's major crops are deficient in lysine and several other amino acids essential for human and animal nutrition. Increasing the content of these amino acids in cereals, our major source of dietary energy, can help feed a global population whose reliance upon dietary protein is growing faster than crop yields. Here we document the heritable expression in rice, the world's major cereal crop, of tRNAlys species that introduce lysine at alternative codons during protein synthesis, resulting in a significant enrichment of the lysine content of proteins in rice seeds without changing the types or quantities of the seed storage proteins.
There is more to tomato fruit colour than candidate carotenoid genes
Authors: Liu Yong‐Sheng , Gur Amit , Ronen Gil , Causse Mathilde , Damidaux René , Buret Michel , Hirschberg Joseph , Zamir Dani
Published: December 2004

Determining gene sequences responsible for complex phenotypes has remained a major objective in modern biology. The candidate gene approach is attempting to link, through mapping analysis, sequences that have a known functional role in the measured phenotype with quantitative trait loci (QTL) that are responsible for the studied variation. To explore the potential of the candidate approach for complex traits we conducted a mapping analysis of QTL for the intensity of the red colour of the tomato fruit (mainly lycopene) and for probes associated with the well‐characterized carotenoid biosynthesis pathway. Seventy‐five tomato introgression lines (ILs), each containing a single homozygous RFLP‐defined chromosome segment from the green‐fruited species Lycopersicon pennellii delimited 107 marker‐defined mapping bins. Three of the bins resolved known qualitative colour mutations for yellow (r) and orange (B and Del) fruits resulting from variation in specific carotenoid biosynthesis genes. Based on trials in different environments, 16 QTL that modified the intensity of the red colour of ripe fruit were assigned to bins. Candidate sequences associated with the carotenoid biosynthesis pathway were mapped to 23 loci. Only five of the QTL co‐segregated with the same bins that contained candidate genes – a number that is expected by chance alone. Furthermore, similar map location of a QTL and a candidate is far from a direct causative relationship between a gene and a phenotype. This study highlights the wealth and complexity of the variation present in the genus Lycopersicon that could be employed for basic research and genetic improvement of fruit colour in tomato.
A short synthetic MAR positively affects transgene expression in rice and Arabidopsis
Authors: Van der Geest Apolonia H. M. , Welter Mary E. , Woosley Aaron T. , Pareddy Dayakar R. , Pavelko Sarah E. , Skokut Michiyo , Ainley William M.
Published: December 2004

Matrix Attachment Regions (MARs) are DNA elements that are thought to influence gene expression by anchoring active chromatin domains to the nuclear matrix. When flanking a construct in transgenic plants, MARs could be useful for enhancing transgene expression. Naturally occurring MARs have a number of sequence features and DNA elements in common, and using different subsets of these sequence elements, three independent synthetic MARs were created. Although short, these MARs were able to bind nuclear scaffold preparations with an affinity equal to or greater than naturally occurring plant MARs. One synthetic MAR was extensively tested for its effect on transgene expression, using different MAR orientations, plant promoters, transformation methods and plant species. This MAR was able to increase average transgene expression and produced integration patterns of lower complexity. These data show the potential of making well defined synthetic MARs and using them to improve transgene expression.
NMR profiling of transgenic peas
Authors: Charlton Adrian , Allnutt Theo , Holmes Stephen , Chisholm James , Bean Samantha , Ellis Noel , Mullineaux Phil , Oehlschlager Sarah
Published: December 2004

A high throughput proton nuclear magnetic resonance spectroscopy method for the metabolite fingerprinting of plants was applied to genetically modified peas (Pisum sativum) to determine whether biochemical changes, so called ‘unintended effects’, beyond those intended by incorporation of a transgene, were detectable. Multivariate analysis of 1H NMR (nuclear magnetic resonance) spectra obtained from uniformly grown glasshouse plants revealed differences between the transgenic and control group that exceeded the natural variation of the plants. When a larger data set of six related transgenic lines was analysed, including a null segregant in addition to the wild‐type control, multivariate analysis showed that the distribution of metabolites in the transgenics was different from that of the null segregant. However, the profile obtained from the wild‐type material was diverse in comparison with both the transgenics and the null segregant, suggesting that the primary cause of the observed differences was that the transformation process selects for a subset of individuals able to undergo the transformation and selection procedures, and that their descendants have a restricted variation in metabolite profile, rather than that the presence of the transgene itself generates these differences.
Leaf senescence is delayed in maize expressing the Agrobacterium IPT gene under the control of a novel maize senescence‐enhanced promoter
Authors: Robson Paul R. H. , Donnison Iain S. , Wang Kan , Frame Bronwyn , Pegg Sue Ellen , Thomas Ann , Thomas Howard
Published: December 2004

We have genetically modified maize plants to delay leaf senescence. A senescence‐enhanced promoter from maize (PSEE1) was used to drive expression of the Agrobacterium cytokinin biosynthesis gene IPT in senescing leaf tissue. Three maize lines expressing IPT from PSEE1, Sg1, Sg2 and Sg3, were analysed in detail, representing mild, intermediate and extreme expression, respectively, of the delayed‐senescence phenotype. Backcross populations segregating for the presence or absence of the PSEE1XbaIPTNOS transgene also simultaneously segregated for the senescence phenotype. At the time of ear leaf emergence, individuals of lines Sg1 and Sg2 segregating for the presence of the transgene carried about three fewer senescing leaves than control (transgene‐minus) segregants, and IPT transcript levels were higher in leaves at incipient senescence than in young leaves. Leaves of transgenic Sg3 plants were significantly greener than controls and progressed directly from fully green to bleached and dead without an intervening yellowing phase. IPT transcript abundance in this line was not related to the initiation of senescence. Extended greenness was accompanied by a delay in the loss of photosynthetic capacity with leaf age. The delayed‐senescence trait was associated with relatively minor changes in morphology and development. The phenotype was particularly emphasized in plants grown in low soil nitrogen. The reduced ability of the extreme transgenic line Sg3 to recycle internal nitrogen from senescing lower leaves accounted for significant chlorosis in emerging younger leaves when plants were grown in low nutrient conditions. This study demonstrates that the agronomically important delayed‐senescence (‘stay‐green’) trait can be engineered into a monocot crop, and is the first example outside Arabidopsis of senescence modification using a homologous senescence‐enhanced promoter.
Transgenic analysis of sugar beet xyloglucan endo‐transglucosylase/hydrolase Bv‐XTH1 and Bv‐XTH2 promoters reveals overlapping tissue‐specific and wound‐inducible expression profiles
Authors: Dimmer Emily , Roden Laura , Cai Daguang , Kingsnorth Crawford , Mutasa‐Göttgens Effie
Published: December 2004

The identification and analysis of tissue‐specific gene regulatory elements will improve our knowledge of the molecular mechanisms that control the growth and development of different plant tissues and offer potentially useful tools for the genetic engineering of plants. A polymerase chain reaction (PCR)‐based 5′‐genome walk from sequences of an isolated sugar beet xyloglucan endo‐transglucosylase hydrolase (XTH) gene led to the isolation of two independent upstream fragments. They were 1332 and 2163 base pairs upstream of the XTH ATG start site, respectively. In vivo transgenic assays in sugar beet hairy roots and Arabidopsis thaliana revealed that both fragments had promoter function and, in A. thaliana, directed expression in vascular tissues within the root, leaves and petals. Promoter activity was also observed in the leaf trichomes and within rapidly expanding stem internodes. Expression driven by both promoters was found to be wound inducible. Overall, the spatial and temporal expression pattern of these promoters suggested that the corresponding Bv‐XTH genes (designated Bv‐XTH1 and Bv‐XTH2) may be involved in secondary cell wall formation. This work provides new insights on molecular mechanisms that could be exploited for the genetic engineering of sugar beet crops.
Multivariate Outlier Detection in Incomplete Survey Data: The Epidemic Algorithm and Transformed Rank Correlations
Authors: Béguin Cédric , Hulliger Beat
Published: December 2004

As a part of the EUREDIT project new methods to detect multivariate outliers in incomplete survey data have been developed. These methods are the first to work with sampling weights and to be able to cope with missing values. Two of these methods are presented here. The epidemic algorithm simulates the propagation of a disease through a population and uses extreme infection times to find outlying observations. Transformed rank correlations are robust estimates of the centre and the scatter of the data. They use a geometric transformation that is based on the rank correlation matrix. The estimates are used to define a Mahalanobis distance that reveals outliers. The two methods are applied to a small data set and to one of the evaluation data sets of the EUREDIT project.
Combining Editing and Imputation Methods: An Experimental Application on Population Census Data
Authors: Manzari Antonia
Published: December 2004

Features of census data make the editing and imputation phase a complex matter. Complex editing and imputation tasks can be tackled by dividing the editing and imputation process into subphases characterized by different problems, and finding appropriate solutions for each of them. An experimental application of the approach of combining different currently used methods for the editing and imputation of population census data is presented.
Defining new roles for plant and rhizobial molecules in sole and mixed plant cultures involving symbiotic legumes
Authors: Dakora Felix D.
Published: December 2004

The view that symbiotic legumes benefit companion and subsequent plant species in intercrop and rotation systems is well accepted. However, the major contributions made separately by legumes and their microsymbionts that do not relate to root‐nodule N2 fixation have been largely ignored. Rhizobia (species of Rhizobium, Bradyrhizobium, Azorhizobium, Allorhizobium, Sinorhizobium and Mesorhizobium) produce chemical molecules that can influence plant development, including phytohormones, lipo‐chito‐oligosaccharide Nod factors, lumichrome, riboflavin and H2 evolved by nitrogenase. When present in soil, Nod factors can stimulate seed germination, promote plant growth and increase grain yields of legume and nonlegume crops, as well as stimulate increased photosynthetic rates following plant leaf spraying. Very low concentrations of lumichrome and H2 released by bacteroids also promote plant growth and increase biomass in a number of plant species grown under field and glasshouse conditions. Rhizobia are known to suppress the population of soil pathogens in agricultural and natural ecosystems and, in addition to forming nodule symbioses with rhizobia, the legume itself releases phenolics that can suppress pathogens and herbivores, solubilize nutrients, and promote growth of mutualistic microbes. Phytosiderophores and organic acid anions exuded by the host plant can further enhance mineral nutrition in the system. This review explores new insights into sole and mixed plant cultures with the aim of identifying novel roles for molecules of legume and microbial origin in natural and agricultural ecosystems.
Ectomycorrhizas and retarded decomposition in aPinus resinosaplantation
Authors: Koide R. T. , Wu T.
Published: December 2004

Ectomycorrhizas may interact with saprotrophic microorganisms to influence decomposition. These interactions are poorly understood.

We buried mesh envelopes filled with either litter or F‐layer material in the forest floor of aPinus resinosaplantation. After 16 months we characterized decomposition, C : N ratio, water content, and the density of four ectomycorrhiza morphotypes.

For both substrates there were negative correlations between ectomycorrhiza density and decomposition, and between ectomycorrhiza density and water content. The relative proportion of morphotypes was significantly different in litter and F‐layer material buried at the same depth in the forest floor.

We conclude that the negative effect of ectomycorrhizas on decomposition could be mediated by extraction of water, particularly in relatively dry years. The ‘Gadgil effect’ may be explained by this phenomenon. In wetter years, water extraction may be less consequential. Also, variation in substrate quality may influence the structure of ectomycorrhizal fungal communities.
Phytochelatin‐based complexes bind various amounts of cadmium in maize seedlings depending on the time of exposure, the concentration of cadmium and the tissue
Authors: Rauser Wilfried E.
Published: December 2004

The aims were to determine the quantities of tissue cadmium (Cd) bound in maize (Zea mays) roots through phytochelatin‐based complexes with changes in time of exposure, the concentration of Cd, the part of the primary root system, and the status of the complexes in shoots.

Six buffer extractions solubilized most tissue Cd and a rapid small‐scale gel filtration resolved the buffer soluble Cd into high and low molecular weight Cd‐binding complexes.

Six buffer extractions, rather than one, effectively represented high and low molecular weight phytochelatin‐based Cd‐binding complexes. The low molecular weight complex predominated in root apices and after 1 d of 3 µm Cd; the high molecular weight complex predominated in mature root parts and after 2 d of exposure. More tissue Cd was bound by both complexes with increasing time of exposure and concentration of Cd. Buffer extracted less Cd from shoots than roots and phytochelatin‐based complexes bound less shoot Cd (29% vs 88%).

The phytochelatin‐based complexes are in a dynamic state dependent on the treatment and they function to bind variable amounts of tissue Cd.
Hybridization as a mechanism of invasion in oaks
Authors: Petit Rémy J. , Bodénès Catherine , Ducousso Alexis , Roussel Guy , Kremer Antoine
Published: December 2004

We review here our own research and related work on hybridization between two widespread and largely sympatric European oak species (Quercus petraeaandQ. robur). There is a near total lack of local differentiation in chloroplast DNA markers between them. A model is proposed to account for this lack of differentiation: invasion by one species of the range occupied by the other through pollen swamping. In support of this model, ecological, palaeoecological and population genetic studies indicate that one species (Q. robur) disperses its seeds better than the other one, that pollen flow is much more efficient than seed flow in oaks and that hybridization and introgression are asymmetric, hence reinforcing the ecological dynamics by facilitating the dispersal ofQ. petraeain regions already colonized byQ. robur. ‘Resurrection’ ofQ. petraeafollowing this wave of hybridization appears to be rapid. More generally, available evidence indicates that hybridization could constitute an important mechanism of dispersal in both natural and human‐induced plant invasions.
Historical inferences from the self‐incompatibility locus
Authors: Igic Boris , Bohs Lynn , Kohn Joshua R.
Published: December 2004

Ancient polymorphism preserved at the self‐incompatibility locus facilitates investigation of historical occurrences far older than extant species. We outline two ways in which studies of the S‐locus can provide insights into patterns of speciation. First, we review evidence concerning the prevalence of founder events in speciation. A dramatic population size reduction is expected to reduce sequence diversity at the S‐locus for millions of years. Only one potential bottleneck is preserved at the S‐locus of the Solanaceae, suggesting that severe population size restrictions rarely occur in successful lineages. This must be interpreted with caution because of the restrictive conditions under which bottlenecks at the S‐locus will be preserved. Second, S‐locus polymorphism provides a novel opportunity to reconstruct, with considerable certainty, the presence or absence of self‐incompatibility among ancestral taxa. We demonstrate this approach using a phylogenetic analysis and find that transitions from self‐incompatibility to self‐compatibility are common and essentially irreversible in the Solanaceae. Self‐incompatibility is ancestral, but self‐compatible taxa currently outnumber self‐incompatible ones. Either self‐incompatibility is going extinct, or the presence of incompatibility increases the diversification rate, maintaining a mixture of self‐incompatible and self‐compatible species in equilibrium. We outline how phylogenetic approaches can be used to determine the effect of incompatibility on diversification.
Respiratory sinus arrhythmia as an index of emotional response in young adults
Authors: Frazier Thomas W. , Strauss Milton E. , Steinhauer Stuart R.
Published: December 2004

The relationship between respiratory sinus arrhythmia (RSA) and valence and arousal remains unclear. In the present study, the associations between emotion responses and tonic or task‐related changes in RSA were assessed. Specifically, the sensitivities of changes in interbeat interval, RSA, and skin conductance to the valence and arousal values of emotional stimuli were examined. This study also explored the association between tonic RSA and subjective, expressive, and physiological emotional responses. Response measures were collected from 56 adults during baseline and film‐viewing periods. Tonic RSA was not significantly related to any of the response measures. Increased skin conductance and decreased RSA were associated with arousal independent of valence. Interbeat interval was related to affective valence and not arousal. These findings suggest that RSA may be a useful adjunct to skin conductance measures in assessing emotional arousal.
Internalization of [DOTA°,125I‐Tyr3]Octreotide by Somatostatin Receptor–Positive Cells In Vitro and In Vivo: Implications for Somatostatin Receptor–Targeted Radio‐guided Surgery
Authors: Hof land Leo J , Breeman Wout A.P. , Krenning Eric P. , De Jong Marion , Waaijers Marlijn , Van Koetsveld Peter M. , Mäcke Helmut R. , Lamberts Steven W.J.
Published: December 2004

We compared internalization of three radioiodinated octreotide (OCT) somatostatin (SS) analogs—[125I‐Tyr3]OCT, [DTPA°,125I‐Tyr3]OCT, and [DOTA°,125I‐Tyr3]OCT—by somatostatin receptor (SSR)‐positive mouse AtT20 pituitary tumor cells and human insulinoma cells. The three SS analogs were internalized in a specific, time‐dependent manner. Internalization was significantly inhibited by pertussis toxin (100 μg/l) by 38%, 43%, and 31%, and by an inhibitor of receptor‐mediated endocytosis (phenyl arsine oxide; 10 μM) by 98%, 94%, and 92%, respectively. Binding affinities of the three radioligands were comparable (0.2, 0.2, and 0.3 nM, respectively). However, [DOTA°,125I‐Tyr3]OCT was internalized in a five‐fold higher amount in comparison with the two other radioligands. A comparably high uptake of [DOTA°,125I‐Tyr3]OCT was found in SSR‐positive organs (pituitary, pancreas, and adrenals) in vivo in rats (a ten‐fold, five‐fold, and eight‐fold higher uptake 4 hr post injection, respectively, compared with the two other radioligands). This resulted in very high target‐background ratios for [DOTA°,125I‐Tyr3]OCT 4 hr post injection amounting to 274, 566, and 623 in the pituitary, adrenals, and pancreas, respectively. Both in vivo and in vitro there was a rpaaid dissociation of radioactivity from the SSR‐positive cells. Main conclusions are that: 1) coupling of chelating groups like DTPA or DOTA to the SS analog [Tyr3]OCT does not prevent the internalization of OCT after binding to SSRs; 2) [DOTA°,125I‐Tyr3]OCT is internalized in a significantly higher amount by AtT20 and human insulinoma cells and in vivo in rats in SSR‐positive organs, in comparison with [DTPA°,125I‐Tyr3]OCT and [125I‐Tyr3]OCT; and 3) the very high target‐background ratios in vivo make radioiodinated [DOTA°,Tyr3]OCT a very suitable ligand for SSR‐targeted radioguided surgery of SSR‐positive human neuroendocrine tumors.
Drugs of Abuse and the Brain
Authors: Leshner Alan I. , Koob George F.
Published: December 2004

New insights into our understanding of drug abuse and addiction have revealed that the desire to use drugs and the process of addiction depend on effects on brain function. Drugs of abuse have been hypothesized to produce their rewarding effects by neuropharmacological actions on a common brain reward circuit called the extended amygdala. The extended amygdala involves the mesolimbic dopamine system and specific subregions of the basal forebrain, such as the shell of the nucleus accumbens, the bed nucleus of the stria terminalis, and the central nucleus of the amygdala. The psychomotor stimulants cocaine and amphetamine activate the mesolimbic dopamine system; opiates activate opioid peptide receptors within and independent of the mesolimbic dopamine system. Sedative hypnotics alter multiple neurotransmitter systems in this circuitry, including: 1) gamma aminobutyric acid; 2) dopamine; 3) serotonin; 4) glutamate; and 5) opioid peptides. Nicotine and tetrahydrocannabinol both activate mesolimbic dopamine function and possibly opioid peptide systems in this circuitry. Repeated and prolonged drug abuse leads to compulsive use, and the mechanism for this transition involves, at the behavioral level, a progressive dysregulation of brain reward circuitry and a recruitment of brain stress systems such as corticotropin‐releasing factor. The molecular mechanisms of signal transduction in these systems are a likely target for residual changes in that they convey allostatic changes in reward set point, which lead to vulnerability to relapse.
The Immunogenetics of Resistance to Malaria
Authors: Hill Adrian V.s.
Published: December 2004

The genetic basis of susceptibility to malaria has been studied extensively using a variety of approaches. The protective role of several erythrocytic variants is now well established. More recently, there has been growing evidence that genes determining a variety of immune responses influence susceptibility to malaria. Some of these genes may specifically affect susceptibility to particular strains of malaria parasite. The recent adoption of genetic linkage approaches supplements the established strategy of assessing candidate gene polymorphisms in case‐control studies. Immunogenetic associations with severe malaria have already suggested new approaches for intervention, and the highly polygenic nature of susceptibility to this disease suggests that the identification and analysis of new susceptibility and resistance loci should be worthwhile.
Glucocorticoids Augment Fibroblast‐Mediated Contraction of Collagen Gels by Inhibition of Endogenous PGE Production
Authors: Sköld C. Magnus , Der Liu Xiang , Zhu Yun Kui , Umino Takeshi , Takigawa Keiichi , Ohkuni Yoshihiro , Ertl Ronald F. , Spurzem John R. , Romberger Debra J. , Brattsand Ralph , Rennard Stephen I.
Published: December 2004

Glucocorticoids are currently regarded as the drug of choice in the treatment of inflammatory airway and lung diseases, however, they are not routinely effective in fibrotic phases of inflammation. In the current study, glucocorticoids were investigated for their ability to affect fibroblast mediated contraction of a three dimensional collagen gel, a measure of one aspect of tissue remodeling. Dexamethasone, budesonide, hydrocortisone and fluticasone propionate were all able to significantly augment fibroblast contractility in a concentration dependent manner. Glucocorticoids also had an augmentative effect on collagen gel contraction mediated by fibroblasts from bronchi, skin and bone marrow. The increased contractility was not due to cell proliferation or to collagen degradation, since the glucocorticoids did not alter the amounts of DNA and hydroxyproline in the gels. The concentration of prostaglandin E2 (PGE2) in supernatant media was lower from glucocorticoid‐treated gels compared to control gels. Consistent with this, addition of exogenous PGE2 to the culture system restored the contractile properties and indomethacin augmented contraction similar to the glucocorticoids suggesting that inhibition of prostaglandins or related eicosanoids may be the mechanism by which the increased contractility occurs. DBcAMP, forskolin and the long lasting β2‐agonist formoterol were able to reverse the effect of the glucocorticoids on fibroblast mediated collagen gel contraction suggesting that enhancers of cAMP can counteract the effect of glucocorticoids. Thus, we provide evidence that glucocorticoids have the ability to directly augment fibroblast contractility by inhibiting fibroblast endogenous PGE synthesis. The findings could be one possible mechanism to explain the poor therapeutic response to glucocorticoids on the later stages of fibrotic diseases.
The Biology of 5‐Lipoxygenase: Function, Structure, and Regulatory Mechanisms
Authors: Silverman Eric S. , Drazen Jeffrey M.
Published: December 2004

5‐Lipoxygenase (5‐LO) catalyzes the two‐step conversion of arachidonic acid to leukotriene A 4 (LTA 4). The first step consists of the oxidation of arachidonic acid to the unstable intermediate 5‐hydroperoxyeicosatetraenoic acid (5‐HPETE), and the second step is the dehydration of 5‐HPETE to form LTA 4. These events are the first committed reactions leading to the synthesis of all leukotrienes and play a critical role in controlling leukotriene production. 5‐LO has evolved many complex structural features and regulatory mechanisms to allow it to fulfill this highly specialized role. The biology of 5‐LO is reviewed here with an emphasis on enzymatic function, protein and gene structure, essential cofactors, and the many regulatory mechanisms controlling its expression.
Client Characteristics and the Cost of Home Care in the Prospective Payment System
Authors: Livesay Jody L. , Hanson Kathleen S. , Anderson Mary Ann , Oelschlaeger Mary
Published: December 2004

Abstract  There has been much speculation in the literature about the effect of the prospective payment system (PPS) on the home care industry but few reports of systematic investigation. Clearly, comprehension of client characteristics is essential for categorizing home care clients into the correct Home Health Resource Groups, for allocating resources appropriately, and for implementing necessary organizational changes to accommodate clients who require variations in the amount of resources predicted by the PPS. The purposes of this study were to compare the characteristics of home health clients that resulted in a financial gain or a financial loss for one agency under the PPS with those of the interim payment system. A secondary data analysis of 140 cases compiled by one not‐for‐profit hospital‐affiliated home care organization was completed. Results suggested that client characteristics of the projected loss group had more recertifications on admission and at the end of the 60‐day episode, a longer stay (3 weeks), and more visits, particularly from skilled nursing. Comprehension of client characteristics and the subsequent ability to adjust for the proper case mix will be crucial if home care agencies are to remain financially viable under the PPS. Replication of this project needs to be done using more variables and multiple sites.
Proceedings of the 1998 Meeting of the Society for Pediatric Dermatology
Authors: Duarte Ana M. , PALLER AMY S.
Published: December 2004

The Society for Pediatric Dermatology held its annual meeting in Cambridge, Massachusetts, on July 23–26, 1998. Selected summaries of presentations at the meeting follow.
Proceedings of the 1998 Meeting of the Society for Pediatric Dermatology
Authors: Duarte Ana M. , BLEI FRANCINE
Published: December 2004

The Society for Pediatric Dermatology held its annual meeting in Cambridge, Massachusetts, on July 23–26, 1998. Selected summaries of presentations at the meeting follow.
The Ectrodactyly‐Ectodermal Dysplasia‐Clefting Syndrome (EEC): Report of Five Cases
Authors: Bigatà Xavier , Bielsa Isabel , Artigas Merce , Azón Antoni , Ribera Miquel , Ferrándiz Carlos
Published: December 2004

Abstract: We report five patients from two different pedigrees with the ectrodactyly‐ectodermal dysplasia‐clefting syndrome (EEC). All had features of ectodermal dysplasia, but only three had limb ectrodactyly and orofacial clefting. The present patients illustrate the great phenotypic variability in the EEC syndrome. As no single feature, including any of the three cardinal signs, is mandatory for syndrome diagnosis, a meticulous examination of all family members is needed.
Tissue‐Engineered Skin in the Healing of Wound Stumps from Limb Amputations Secondary to Purpura Fulminans
Authors: Greenberg J. E. , Falabella A. F. , Bello Y. M. , Schachner L. A.
Published: December 2004

Abstract: Currently wound treatment options of amputation stumps due to purpura fulminans include healing by secondary intention from wound debridement, split‐thickness skin grafting, tissue and muscle flaps, plantar skin free transfer, skin expansion, artificial skin, and hyperbaric oxygen therapy. We saw a 6‐month‐old girl with purpura fulminans as a complication of meningococcemia. She developed necrosis of the distal extremities resulting in bilateral amputation of the lower limbs. Shortly thereafter the leg stumps also became necrosed and she underwent unsuccessful split‐thickness grafts of lower limb ulcers. The patient's difficult‐to‐heal wounds made her an excellent candidate for treatment with tissue‐engineered skin. At 10 months of age, this was applied to her previously nonhealing wounds. The tissue‐engineered skin induced rapid healing of the patient's chronic amputation stump ulcers and provided her with substantial pain relief. In conclusion, tissue‐engineered skin appears to be a potential beneficial treatment for chronic wounds in children with nonhealing amputation stumps.
Sacral Hemangioma with Sinus Tract in an Infant
Authors: Winstanley Douglas , Graham Brad , Blair Mark , Linfesty Ron , Tomita Sandra , Matthews Jeanette
Published: December 2004

Abstract: Congenital midline cutaneous lesions should always alert the clinician to the possibility of spinal dysraphism. These lesions can take many different forms. The physician should be cognizant of such lesions in order to avoid potential neurologic complications. We present a patient with a midline sacral hemangioma associated with a congenital enteric sinus cyst, a previously unreported association.
Tinea Capitis Due to Trichophyton soudanense in Cincinnati, Ohio, in Internationally Adopted Children from Liberia
Authors: Markey Robin J. , Staat Mary Allen , Gerrety Mary Jo T. , Lucky Anne W.
Published: December 2004

Abstract: Two sisters, ages 5 and 6 years, who were adopted from Liberia, presented in Cincinnati, Ohio, with tinea capitis. Fungal cultures grew Trichophyton soudanense, a dermatophyte rarely seen in North America. Both girls had multiple other infections. They responded well to therapy with oral griseofulvin and topical selenium sulfide. With the current increase in international travel and adoption, nonendemic dermatophyte infections such as this need to be recognized.
Role of Legumes in Release of Successionally Arrested Grasslands in the Central Hills of Sri Lanka
Authors: Ashton P. M. S. , Samarasinghe S. J. , Gunatilleke I. A. U. N. , Gunatilleke C. V. S.
Published: December 2004

Most of the world's forest has been cleared, cultivated, and then often abandoned. In many instances these areas have changed to successionally arrested grasslands, shrublands, or fernlands maintained by frequent fires and high herbivore populations. Many studies have shown that various herbaceous, nitrogen‐fixing legumes can protect soil surfaces, retain soil moisture, improve soil fertility, and retard ground fires. Our objective was to ascertain if some of these species can potentially inhibit herbivory and satisfactorily establish in these arrested grassland areas to serve as sites for reforestation. We evaluated the potential for four species of nitrogen‐fixing legumes (Calapogonium mucunoides, Centrosema pubescens, Desmodium ovalifolium, andPueraria phaseoloides) to establish on exposed soil within successionally arrested grasslands ofPanicum maximumandCymbopogon nardusin the central hills of Sri Lanka. Four different sites within rectangular grassland areas were cleared of graminoids and sown with seed of each legume. Half of each clearing was protected from browsing rabbits and porcupines, and half was not protected. After 6 months, certain plots were destructively sampled to determine dry biomass gain for each species and treatment. Analyses of variance were performed to test for differences among sites, treatments, and species. All three factors revealed differences, indicating that species must be matched to site. On sites with high amounts of herbivory,D. ovalifoliumhad the greatest dry biomass gain after 6 months of growth, possibly because of its relatively low nitrogen and moisture content. Where herbivory was absent,P. phaseoloidesandC. muconoideshad the greatest dry biomass gain. Dry biomass gain of all four legume ground covers was low on sites with lowest pH and nutrient concentrations. Under conditions of low relative fertility and low pH, establishment of the tested legumes failed. Though soil moisture availability was not measured, we speculate that these low fertility sites were also prone to drought. Findings support the site‐specific establishment of legume species for purposes of reforestation and watershed protection in central Sri Lanka. This work is applicable to other regions particularly dominated by successionally arrested grasslands with similar circumstances in other parts of south and southeast Asia.
Stabilization and Erosion Control Value of Oyster Cultch for Intertidal Marsh
Authors: Meyer David L. , Townsend Edward C. , Thayer Gordon W.
Published: December 2004

Oyster cultch was added to the lower intertidal fringe of three created Spartina alterniflora marshes to examine its value in protecting the marsh from erosion. Twelve 5‐m‐wide plots were established at each site, with six randomly selected plots unaltered (non‐cultched) and cultch added to the remaining (cultched) plots. Within each cultched plot, cultch was placed along the low tide fringe of the marsh during July 1992, in a band 1.5 m wide by 0.25 m deep. Marsh‐edge vegetation stability and sediment erosion were measured for each plot from September 1992 to April 1994. Significant differences (p < 0.05) in marsh‐edge vegetation change were detected at the only south‐facing site after a major southwester storm. Significantly different rates of sediment erosion and accretion also were observed at this same site. Areas upland of the marsh edge in the cultched areas showed an average accretion of 6.3 cm, while noncultched treatment areas showed an average loss of 3.2 cm. A second site, with a northern orientation, also experienced differential sediment accretion and erosion between treatment type, caused instead by boat wakes that were magnified by the abutment of a dredge effluent pipe across the entire front fringe of the site. During this period we observed significant differences in sediment accumulation, with the areas upland of the marsh edge in the cultched treatment having an average accretion of 2.9 cm and the noncultched an average loss of 1.3 cm.
Morphology of Cultured Human Epidermal Melanocytes Observed by Atomic Force Microscopy
Authors: Zhang Ru‐zhi , Zhu Wen‐yuan , Xia Ming‐yu , Feng Yan
Published: December 2004

The objective of this study was to image the surface structure of cultured human epidermal melanocytes using atomic force microscopy (AFM). Epidermis obtained from human foreskins was treated with 0.5% dispase. Cell suspensions of the epidermis were prepared and seeded in six‐well plates, in which sheets of mica had been placed. Samples for AFM were fixed on mica and scanning AFM images were captured by contacting and tapping modes operated under normal atmospheric pressure and temperature. Human epidermal melanocytes exhibited rounded, oval, triangular or quadrangular perikarya from which eight to 10 thick dendrites arose. These dendrites first bifurcated near the soma and then divided profusely into daughter branches, which spread out in all directions. We observed string‐like long thin projections, growth cones and shorter thicker projections, which arose from the dendritic shafts, in which groups of melanosomes were arrayed. In addition to such structures, the most striking feature was the presence of filopodia arising from the melanocyte dendrite tips and the melanocyte cell body, many of which contained melanosomes. The termini of dendrites formed unbranched terminal protrusions (approximately 1500–2000 nm wide) consisting of two to three melanosomes wrapped in an arc, with their filopodia extending outwards. The tips of these structures also appeared to be squeezed and finally pinched off by the melanocyte to form a pouch filled with numerous melanosomes. We conclude that secondary and tertiary branches and subordinate branches might take part in transferring melanosomes into keratinocytes in addition to the transfer through the tips of the dendritic shafts. The melanin granules were expelled by exocytosis.
Interference of Some Tryptophan Metabolites in the Formation of Melanin In Vitro
Authors: Soddu Giulia , Sanjust Enrico , Murgia Sergio , Rescigno Antonio
Published: December 2004

Melanin (eumelanin) is commonly produced in mammals starting from tyrosine and/or 3,4‐dioxyphenylalanine (DOPA) under the action of tyrosinase. 3‐Hydroxyanthranilic acid and 3‐hydroxykynurenine are intermediates occurring in the kynurenine pathway of tryptophan catabolism. In this paper, we show that these substances can interfere in melanin formation in vitro when tyrosine or DOPA is oxidized by molecular oxygen under catalysis by tyrosinase. In particular, when 3‐hydroxyanthranilic acid is present, a brown and apparently water‐soluble pigment is formed, whereas the typical eumelanin granules seem to become more and more rare as the concentration of 3‐hydroxyanthranilic acid increases. Also in the presence of the latter, the rate of tyrosine and/or DOPA consumption decreases. A very complicated 13C‐NMR spectrum indicates the high complexity of the reaction. This involves both the true melanin precursor(s) and the tryptophan metabolite, even if with peculiar mechanism and kinetics. When 3‐hydroxykynurenine is substituted for 3‐hydroxyanthranilic acid the reaction leads to reddish pigments whereas xanthommatins (the typical oxidation products of 3‐hydroxykynurenine) are absent. A possible relationship between some dischromic pathologies and tryptophan metabolic disorders is suggested.
Experiments with Plasma Moving through Neutral Gas
Authors: Fahleson Ulf V.
Published: December 2004

The behavior of a rotating plasma machine has been investigated. It is found that when the gas pressure and the current are varied within very wide limits the burning voltage remains constant. The voltage is proportional to the magnetic field. The reason for this behavior seems to be the existence of a critical velocity, above which a strong interaction between a plasma and a neutral gas takes place.
Longitudinal Ion Oscillations in a Hot Plasma
Authors: Fried Burton D. , Gould Roy W.
Published: December 2004

Linearized, longitudinal waves in a hot plasma include, besides the familiar electron plasma oscillations, in which the frequency ω is of order ωp = (4πne2/m)½, also ion plasma oscillations with ω ≈ ωp(m/M)½. The properties of the latter are explored using a Vlasov equation description of the plasma. For equal ion and electron temperatures, Te = Ti, there exists a discrete sequence of ion oscillations, but all are strongly damped, i.e., have -Im ω/Re ω ⪞ 0.5, and hence are not likely to be observable. The ratio Im ω/Re ω can be made to approach zero (facilitating detection of the waves) by either increasing Te/Ti or by producing a current flow in the plasma. In the latter case, Im ω can even be made positive (corresponding to growing waves), the current required for this being smaller the larger the value of Te/Ti. This growing wave is just the familiar two-stream instability which is thus seen to be an unstable ion oscillation. It is also noteworthy that the ion oscillations, which for small k have the properties usually associated with an acoustic wave (longitudinal polarization, ω ∝ k), are obtained using a formalism which is sometimes designated as ``collisionless.''
Surface Electroconvection
Authors: Malkus W. V. R. , Veronis G.
Published: December 2004

An electric field can produce steady cellular motions in the interface region of two immiscible semiconducting fluids. The theory of this instability is explored. The characteristic parameter is found to depend upon the difference in conductivity of the fluids and the curvature of the interface. Quantitative finite amplitude experiments established that the electric current produced by the cellular motions is proportional to the characteristic parameter minus the critical value of this parameter.
Effects of Inhomogeneity and of Shear Flow in Weak Turbulent Fields
Authors: Deissler Robert G.
Published: December 2004

Spectra for weak turbulence are found for: (1) turbulence inhomogeneous in the direction of a uniform mean velocity; (2) an initially homogeneous turbulence becoming inhomogeneous in a transverse direction because of the presence of boundaries; and (3) turbulence homogeneous with a uniform mean transverse velocity gradient. The treatment is based on two-point correlation and spectral equations. The effect of inhomogeneity is to cause a diffusion of turbulence in the direction of decreasing turbulent intensity. Longitudinal inhomogeneity produces an accumulation of energy mainly in the high wave-number portions of the energy spectrum, whereas the transverse inhomogeneity causes a depletion of energy at a point in the fluid and does not alter the shape of the spectrum. For homogeneous turbulence with a uniform transverse velocity gradient, energy is transferred from the mean flow into the turbulence by a turbulent production term in the spectral equation. At high velocity gradients the production spectrum shifts toward the low wave-number region and the dissipation spectrum toward the high wave-number region. The pressure-force term, which is dependent on the velocity gradient, transfers energy between the directional components in such a way as to oppose local isotropy in the high wave-number region. Although triple correlations are neglected (low-turbulence Reynolds number), a term containing the mean velocity gradient occurs in the spectral equation which is interpreted as transferring energy between wave numbers.