bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Macroscopic and Local Strains in a Three‐Dimensional Woven C/SiC Composite
Authors: Yang Q. D. , Rugg K. L. , Cox B. N. , Marshall D. B.
Published: March 2005

Engineering tests and full‐field strain measurements are used to assess the accuracy of predictions made by the Binary Model, a computational tool for textile composites. The test case is a carbon fiber/SiC matrix composite, in which the reinforcement is a three‐dimensional angle‐interlock weave. The test composites are thin, having been designed for heat exchanger applications. The thinness leads to strong variations in local strains and strong effects of tow waviness upon macroscopic elasticity. The model performs well in predicting both local variations in strain and macroscopic elasticity. The effect of averaging local strains over variable gauge lengths is explored. Strains averaged over an appropriate gauge length have recently been proposed as the preferred measures of strain for use in local failure criteria.
Anatomy and Physiology of Pain Referral Patterns in Primary and Cervicogenic Headache Disorders
Authors: Bartsch T. , Goadsby P. J.
Published: March 2005

The clinical presentation of pain in primary headache disorders, such as migraine and cervicogenic headache, shows that the trigeminal and cervical innervation territories frequently are not respected during an attack. Here we review evidence that trigeminal afferents innervating the meninges, and cervical afferents in the greater occipital nerve (GON), have synaptic convergent input onto the same second‐order neurons in the trigeminocervical complex. Furthermore, dynamic changes of excitability in terms of a sensitization to noxious input may occur on the central neuron level. The possible role of segmental mechanisms in the spinal cord and of inhibitory projections from brainstem structures such as the periaqueductal gray (PAG) in pain processing is discussed in view of data using neurostimulation of peripheral nerves in pain modulation. Recent experimental animal and human studies have facilitated our understanding of the role of these basic mechanisms in the spread, referral, and maintenance of pain in headache.
Calcium oscillations in interstitial cells of the rabbit urethra
Authors: Johnston L. , Sergeant G. P. , Hollywood M. A. , Thornbury K. D. , McHale N. G.
Published: March 2005

Measurements were made (using fast confocal microscopy) of intracellular Ca2+ levels in fluo‐4 loaded interstitial cells isolated from the rabbit urethra. These cells exhibited regular Ca2+ oscillations which were associated with spontaneous transient inward currents recorded under voltage clamp. Interference with d‐myo‐inositol 1,4,5‐trisphosphate (IP3) induced Ca2+ release using 100 μm 2‐aminoethoxydiphenyl borate, and the phospholipase C (PLC) inhibitors 2‐nitro‐4‐carboxyphenyl N,N‐diphenylcarbamate and U73122 decreased the amplitude of spontaneous oscillations but did not abolish them. However, oscillations were abolished when ryanodine receptors were blocked with tetracaine or ryanodine. Oscillations ceased in the absence of external Ca2+, and frequency was directly proportional to the external Ca2+ concentration. Frequency of Ca2+ oscillation was reduced by SKF‐96365, but not by nifedipine. Lanthanum and cadmium completely blocked oscillations. These results suggest that Ca2+ oscillations in isolated rabbit urethral interstitial cells are initiated by Ca2+ release from ryanodine‐sensitive intracellular stores, that oscillation frequency is very sensitive to the external Ca2+ concentration and that conversion of the primary oscillation to a propagated Ca2+ wave depends upon IP3‐induced Ca2+ release.
The distribution of cutaneous sudomotor and alliesthesial thermosensitivity in mildly heat‐stressed humans: an open‐loop approach
Authors: Cotter James D. , Taylor Nigel A. S.
Published: March 2005

The distribution of cutaneous thermosensitivity has not been determined in humans for the control of autonomic or behavioural thermoregulation under open‐loop conditions. We therefore examined local cutaneous warm and cool sensitivities for sweating and whole‐body thermal discomfort (as a measure of alliesthesia). Thirteen males rested supine during warming (+4°C), and mild (−4°C) and moderate (−11°C) cooling of ten skin sites (274 cm2), whilst the core and remaining skin temperatures were clamped above the sweat threshold using a water‐perfusion suit and climate chamber. Local thermosensitivities were calculated from changes in sweat rates (pooled from sweat capsules on all limbs) and thermal discomfort, relative to the changes in local skin temperature. Thermosensitivities were examined across local sites and body segments (e.g. torso, limbs). The face displayed stronger cold (−11°C) sensitivity than the forearm, thigh, leg and foot (P= 0.01), and was 2–5 times more thermosensitive than any other segment for both sudomotor and discomfort responses (P= 0.01). The face also showed greater warmth sensitivity than the limbs for sudomotor control and discomfort (P= 0.01). The limb extremities ranked as the least thermosensitive segment for both responses during warming, and for discomfort responses during moderate cooling (−11°C). Approximately 70% of the local variance in sudomotor sensitivity was common to the alliesthesial sensitivity. We believe these open‐loop methods have provided the first clear evidence for a greater facial thermosensitivity for sweating and whole‐body thermal discomfort.
Placental angiogenesis in sheep models of compromised pregnancy
Authors: Reynolds Lawrence P. , Borowicz Pawel P. , Vonnahme Kimberly A. , Johnson Mary Lynn , Grazul‐Bilska Anna T. , Redmer Dale A. , Caton Joel S.
Published: March 2005

Because the placenta is the organ that transports nutrients, respiratory gases and wastes between the maternal and fetal systems, development of its vascular beds is essential to normal placental function, and thus in supporting normal fetal growth. Compromised fetal growth and development have adverse health consequences during the neonatal period and throughout adult life. To establish the role of placental angiogenesis in compromised pregnancies, we first evaluated the pattern of placental angiogenesis and expression of angiogenic factors throughout normal pregnancy. In addition, we and others have established a variety of sheep models to evaluate the effects on fetal growth of various factors including maternal nutrient excess or deprivation and specific nutrients, maternal age, maternal and fetal genotype, increased numbers of fetuses, environmental thermal stress, and high altitude (hypobaric) conditions. Although placental angiogenesis is altered in each of these models in which fetal growth is adversely affected, the specific effect on placental angiogenesis depends on the type of ‘stress’ to which the pregnancy is subjected, and also differs between the fetal and maternal systems and between genotypes. We believe that the models of compromised pregnancy and the methods described in this review will enable us to develop a much better understanding of the mechanisms responsible for alterations in placental vascular development.
Inner and outer retinal pathways both contribute to surround inhibition of salamander ganglion cells
Authors: Ichinose Tomomi , Lukasiewicz Peter D.
Published: March 2005

Illumination of the receptive‐field surround reduces the sensitivity of a retinal ganglion cell to centre illumination. The steady, antagonistic receptive‐field surround of retinal ganglion cells is classically attributed to the signalling of horizontal cells in the outer plexiform layer (OPL). However, amacrine cell signalling in the inner plexiform layer (IPL) also contributes to the steady receptive‐field surround of the ganglion cell. We examined the contributions of these two forms of presynaptic lateral inhibition to ganglion cell light sensitivity by measuring the effects of surround illumination on EPSCs evoked by centre illumination. GABAC receptor antagonists reduced inhibition attributed to dim surround illumination, suggesting that this inhibition was mediated by signalling to bipolar cell axon terminals. Brighter surround illumination further reduced the light sensitivity of the ganglion cell. The bright surround effects on the EPSCs were insensitive to GABA receptor blockers. Perturbing outer retinal signalling with either carbenoxolone or cobalt blocked the effects of the bright surround illumination, but not the effects of dim surround illumination. We found that the light sensitivities of presynaptic, inhibitory pathways in the IPL and OPL were different. GABAC receptor blockers reduced dim surround inhibition, suggesting it was mediated in the IPL. By contrast, carbenoxolone and cobalt reduced bright surround, suggesting it was mediated by horizontal cells in the OPL. Direct amacrine cell input to ganglion cells, mediated by GABAA receptors, comprised another surround pathway that was most effectively activated by bright illumination. Our results suggest that surround activation of lateral pathways in the IPL and OPL differently modulate the sensitivity of the ganglion cell to centre illumination.
Agonist activation of arachidonate‐regulated Ca2+‐selective (ARC) channels in murine parotid and pancreatic acinar cells
Authors: Mignen Olivier , Thompson Jill L. , Yule David I. , Shuttleworth Trevor J.
Published: March 2005

ARC channels (arachidonate‐regulated Ca2+‐selective channels) are a novel type of highly Ca2+‐selective channel that are specifically activated by low concentrations of agonist‐induced arachidonic acid. This activation occurs in the absence of any depletion of internal Ca2+ stores (i.e. they are ‘non‐capacitative’). Previous studies in HEK293 cells have shown that these channels provide the predominant pathway for the entry of Ca2+ seen at low agonist concentrations where oscillatory [Ca2+]i signals are typically produced. In contrast, activation of the more widely studied store‐operated Ca2+ channels (e.g. CRAC channels) is only seen at higher agonist concentrations where sustained ‘plateau‐type’[Ca2+]i responses are observed. We have now demonstrated the presence of ARC channels in both parotid and pancreatic acinar cells and shown that, again, they are specifically activated by the low concentrations of appropriate agonists (carbachol in the parotid, and both carbachol and cholecystokinin in the pancreas) that are associated with oscillatory [Ca2+]i signals in these cells. Uncoupling the receptor‐mediated activation of cytosolic phospholipase A2 (cPLA2) with isotetrandrine reduces the activation of the ARC channels by carbachol and, correspondingly, markedly inhibits the [Ca2+]i signals induced by low carbachol concentrations, whilst those signals seen at high agonist concentrations are essentially unaffected. Interestingly, in the pancreatic acinar cells, activation by cholecystokinin induces a current through the ARC channels that is only approximately 60% of that seen with carbachol. This is consistent with previous reports indicating that carbachol‐induced [Ca2+]i signals in these cells are much more dependent on Ca2+ entry than are the cholecystokinin‐induced responses.
Tropical Isles, Icy Seas, and Empire
Authors: Winters R. Scott
Published: March 2005

William Hodges 1744-1797
The Art of Exploration.
Geoff Quilley, Curator
. Organized by the National Maritime Museum, Greenwich, UK, and the Yale Center for British Art, New Haven, CT. At the Yale Center for British Art through 24 April 2005.
http://ycba.yale.edu

William Hodges 1744-1797
The Art of Exploration.
Geoff Quilley and John Bonehill, Eds.
. Yale University Press, New Haven, CT, 2004. 224 pp. $60, £40. ISBN 0-300-10376-X.

This exhibit and the accompanying catalog offer a reappraisal of the work and reputation of the landscape painter who accompanied Cook's second voyage to the South Pacific.
Study of Ultrathin Prussian Blue Films Using in situ Electrochemical Surface Plasmon Resonance
Authors: Lupu Stelian , Pigani Laura , Seeber Renato , Terzi Fabio , Zanardi Chiara
Published: March 2005

Characterisation of ultrathin Prussian Blue films has been performed using in situ electrochemical surface plasmon resonance technique. Prussian Blue films have been prepared by potentiostatic method on a gold-coated glass surface plasmon resonance sensor. The electrochemical reduction of Prussian Blue to Prussian White and oxidation to Berlin Green are accompanied by a change of the refractive index; the system shows repeating voltammetric responses over subsequent potential cycles. The surface plasmon resonance signal is capable of evidencing minute electrochemically induced changes in the inorganic film coating the electrode.
Voltammetric Determination of Mitomycin c Using a Chemically-Modified Glassy Carbon Electrode
Authors: Qu Wanyun , Wang Hong , Wu Kangbing
Published: March 2005

An electrochemical method for the direct determination of mitomycin c (MMC), based on a multi wall carbon nanotube (MWNT)-modified electrode, has been developed. A well-shaped and highly sensitive oxidation peak at 0.79 V was observed on the MWNT-modified electrode for MMC. Further studies show strong evidence that MWNT-modified electrode significantly enhances the sensitivity of determination of MMC since the oxidation peak current of MMC increases remarkably, compared with that with a bare glassy carbon electrode. All the experimental parameters such as pH, scan rate, accumulation conditions, have been examined. A sensitive linear voltammetric response for MMC was obtained over the concentration range of 2.5 × 10-7-1.0 × 10-4 mol/l; the detection limit is 8 × 10-8 mol/l. Compared with other methods, this new-proposed method possesses advantages such as high sensitivity, fast response, low cost and simplicity. Eventually, the proposed method has been successfully employed to detect MMC in urine samples.
A long-term, spatially replicated experimental test of the effect of marine reserves on local fish yields
Authors: Alcala Angel C , Russ Garry R , Maypa Aileen P , Calumpong Hilconida P
Published: March 2005

Do no-take marine reserves affect fishery yields? Manipulations of reserve status, and yield estimates, were made at two Philippine islands over two decades. Twenty-five percent and ten percent, respectively, of the coral reefs at Sumilon and Apo islands were made no-take reserves in 1974 and 1982. Biomass of target fish increased inside the no-take reserves 3- to 4.5-fold over 918 years. Biomass did not increase outside each reserve. Protection of the Sumilon reserve ceased in 1984. Biomass of targeted fish in the reserve and trap and gillnet catches of these fish declined by 42.7% and 40%, respectively, by 1985. The reserve was reprotected from 1987 to 1991 and from 1995 to 2001. Fish biomass increased in the reserve by 27.2%. Trap and gillnet catches outside the reserve increased 26.9% by 2001. The Apo reserve was protected from 1982 to 2001. Total catch of major fish families was significantly higher after (19852001) than before (1981) reserve establishment at Apo, increasing 41.3% between 1981 and 19982001. These experiments, plus spillover evidence, suggest that marine reserves may help maintain, or even enhance, local fishery yields in the long-term.
Relationship of otolith strontium-to-calcium ratios and salinity: experimental validation for juvenile salmonids
Authors: Zimmerman Christian E
Published: March 2005

Analysis of otolith strontium (Sr) or strontium-to-calcium (Sr:Ca) ratios provides a powerful tool to reconstruct the chronology of migration among salinity environments for diadromous salmonids. Although use of this method has been validated by examination of known individuals and translocation experiments, it has never been validated under controlled experimental conditions. In this study, incorporation of otolith Sr was tested across a range of salinities and resulting levels of ambient Sr and Ca concentrations in juvenile chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), sockeye salmon (Oncorhynchus nerka), rainbow trout (Onco rhynchus mykiss), and Arctic char (Salvelinus alpinus). Experimental water was mixed, using stream water and seawater as end members, to create experimental salinities of 0.1, 6.3, 12.7, 18.6, 25.5, and 33.0 psu. Otolith Sr and Sr:Ca ratios were significantly related to salinity for all species (r2 range: 0.800.91) but provide only enough predictive resolution to discriminate among fresh water, brackish water, and saltwater residency. These results validate the use of otolith Sr:Ca ratios to broadly discriminate salinity histories encountered by salmonids but highlight the need for further research concerning the influence of osmoregulation and physiological changes associated with smolting on otolith microchemistry.
Resmoltification in wild, anadromous Arctic char (Salvelinus alpinus): a survey of osmoregulatory, metabolic, and endocrine changes preceding annual seawater migration
Authors: Aas-Hansen Øyvind , Vijayan Mathilakath M , Johnsen Helge K , Cameron Colin , Jørgensen Even H
Published: March 2005

Anadromous Arctic char (Salvelinus alpinus) migrate to seawater every summer for feeding and spend the rest of the year overwintering in fresh water. We investigated whether annual seawater migration is preceded by changes in hyposmoregulatory capacity, intermediary metabolism, and the plasma levels of hormones known to play a role in salmonid seawater preadaptation (smoltification). Wild, anadromous Arctic char were sampled in their overwintering lake in April and May and during the period of downstream migration in June. Our results demonstrate a fourfold seasonal increase in gill Na+/K+ATPase activity, with maximum levels in descending migrants that also displayed prime hyposmoregulatory capacity. Hepatosomatic index and activities of key liver enzymes also increased during spring, indicating a general increase in liver metabolic capacity. These changes were accompanied by increased plasma cortisol and thyroxine levels, decreased plasma growth hormone levels, and unchanged plasma levels of insulin-like growth factor-I and 3,5,3′-triiodothyronine. Our results indicate that wild, anadromous Arctic char resmoltify every spring, and this involves a shift from an energy-conserving overwintering state to a state where they become osmotically and metabolically prepared for their annual feeding migration to seawater.
The impact of a benthic filter feeder: limitations imposed by physical transport of algae to the benthos
Authors: Edwards William J , Rehmann Chris R , McDonald Ellen , Culver David A
Published: March 2005

We used an acoustic Doppler profiler to investigate the hydrodynamics of a nearshore site in western Lake Erie, and we incorporated the measured parameters in numerical simulations of phytoplankton consumption by benthic zebra mussels (Dreissena polymorpha) to examine the link between pelagic production and benthic filter feeders. Daily-averaged eddy diffusivities varied from 105 to 104 m2·s1 at our site. Our simulations demonstrate that diffusivities of this order decrease near-bed algal biomass, while algal biomass in the pelagic remains relatively unaffected. Between 8% and 67% of the algal biomass in the water column could be consumed daily, depending on the shape and magnitude of the diffusivity profile. Correspondingly, in situ vertical biomass profiles showed a near-bed zone of algal depletion, but no impact was observed near the surface. The impact of the zebra mussel in nearshore regions is expected to be stronger than in deeper open water. The flow of algal biomass into the benthos was tightly coupled with turbulent mixing, suggesting that open water algal consumption by zebra mussels is small compared with previously published estimates that ignored vertical turbulent mixing processes.
Distribution and frequency of Cronartium flaccidum on Melampyrum spp. in Finland
Authors: Kaitera Juha , Nuorteva Heikki , Hantula Jarkko
Published: March 2005

Distribution and frequency of Cronartium flaccidum telia were investigated on Melampyrum spp. growing wild in 355 Scots pine stands in Finland. Telia were found for the first time on M. arvense in Finland and for the first time on M. pratense and M. nemorosum in natural forests anywhere. Cronartium flaccidum telia were found in 22% of all stands with M. sylvaticum, 3% of stands with M. pratense, 12% of stands with M. nemorosum, 100% of stands with M. arvense, and 0% of stands with M. cristatum. Melampyrum spp. with telia were mostly found in northern Finland. The proportions of stands with telia and of plants with telia per stand, the frequency of telia-bearing leaves per plant, and the average number of telia per leaf were greater for M. sylvaticum than for most of the other Melampyrum species. In severely affected pine stands, telia were frequent on M. sylvaticum, but scarce or lacking on M. pratense. On sites with M. sylvaticum, the respective proportion of telia-bearing plants was significantly higher in young development classes and severely diseased stands than in older development classes and slightly damaged stands. The results suggest that the main host of C. flaccidum is M. sylvaticum in northern Finland.
Indicators of avian nest predation and parental activity in a managed boreal forest: an assessment at two spatial scales
Authors: Ibarzabal Jacques , Desrochers André
Published: March 2005

Studies of avian nesting success at the landscape level often use a single indirect measure to evaluate nest predation or parental activity. During two summers at Forêt Montmorency, Quebec, we analyzed and compared three indirect measures of nest predation risk: detection of two nest predators, (1) red squirrel (Tamiasciurus hudsonicus Erxleben) and (2) gray jay (Perisoreus canadensis L.), (3) depredation of bait, and direct observations of parental activity (mostly food transported by adults) at 316 stations over a 230-km2area. We assessed the relationship between these indicators and three landscape-structure variables (total forested area, total core area, and total edge length) at two spatial scales (83 and 1610 ha). Nest predators were generally present at <30% of stations, <20% of baits were depredated, and >40% of stations exhibited evidence of broods. Bait depredation and the detection of jays or squirrels were correlated, but we found no associations between nest predation and parental activity indicators. Indicators of nest predation and parental activity were not significantly heterogeneous over the study area, despite substantial variation of landscape structure. We argue that parental activity indicators may be more reliable than nest predation indicators, but only as a coarse way to detect variation in nesting success.
THE ANALYSIS OF THE STOCHASTICALLY FORCED PERIODIC ATTRACTORS FOR CHUA'S CIRCUIT
Authors: YU. RYAGIN MIKHAIL , RYASHKO LEV B.
Published: March 2005

This report shows the results of sensitivity analysis for Chua's circuit periodic attractors under small disturbances. Sensitivity analysis is based on the quasipotential method.

Quasipotential's first approximation in the neighborhood of the limit cycle is defined by the matrix of orbital quadratic form, named stochastic sensitivity function (SSF).

SSF is defined for the points of the nonperturbed limit cycle and can be computed using the numerical algorithm.

Stochastic sensitivity of the limit cycles for the Chua's circuit period doubling cascade is investigated. The growth of the stochastic sensitivity under transition to chaos is shown.
A NEW STATISTICAL METHOD FOR FILTERING AND ENTROPY ESTIMATION OF A CHAOTIC MAP FROM NOISY DATA
Authors: BABU G. JOGESH , BOYARSKY ABRAHAM , CHAUBEY YOGENDRA P. , GÓRA PAWEL
Published: March 2005

We consider a discrete time deterministic chaotic dynamical system, xn+1=τ(xn), where τ is a nonlinear map of the unit interval into itself. We assume that τ is piecewise expanding and piecewise C2. The effects of noise contamination are modeled by xn+1=τ(xn)+ξn, where ξn is an independent random variable with small noise amplitude. A new statistical method is presented for filtering τ and estimating the metric entropy of τ from observed noisy data.
THE DYNAMICS OF SYSTEMS OF COMPLEX NONLINEAR OSCILLATORS: A REVIEW
Authors: MAHMOUD GAMAL M. , BOUNTIS TASSOS
Published: March 2005

Dynamical systems in the real domain are currently one of the most popular areas of scientific study. A wealth of new phenomena of bifurcations and chaos has been discovered concerning the dynamics of nonlinear systems in real phase space. There is, however, a wide variety of physical problems, which, from a mathematical point of view, can be more conveniently studied using complex variables. The main advantage of introducing complex variables is the reduction of phase space dimensions by a half. In this survey, we shall focus on such classes of autonomous, parametrically excited and modulated systems of complex nonlinear oscillators. We first describe appropriate perturbation approaches, which have been specially adapted to study periodic solutions, their stability and control. The stability analysis of these fundamental periodic solutions, though local by itself, can yield considerable information about more global properties of the dynamics, since it is in the vicinity of such solutions that the largest regions of regular or chaotic motion are observed, depending on whether the periodic solution is, respectively, stable or unstable. We then summarize some recent studies on fixed points, periodic solutions, strange attractors, chaotic behavior and the problem of chaos control in systems of complex oscillators. Some important applications in physics, mechanics and engineering are mentioned. The connection with a class of complex partial differential equations, which contains such famous examples, as the nonlinear Schrödinger and Ginzburg–Landau equations is also discussed. These complex equations play an important role in many branches of physics, e.g. fluids, superconductors, plasma physics, geophysical fluids, modulated optical waves and electromagnetic fields.
MODULATED STANDING WAVES RESULTING FROM A HOPF–WAVE INTERACTION IN A CHEMICAL MODEL
Authors: PEÑA B. , PÉREZ–GARCÍA C. , BESTEHORN M.
Published: March 2005

A new reactive model of three dynamical variables is proposed, which exhibits Hopf and Wave instabilities. One-dimensional evolutions of this model reveal several kinds of oscillations. A perturbative stability analysis around the stationary fixed point, leads to amplitude equations for the excited modes in the system. Our attention is focused on modulated standing waves (MSW) that result from the interaction between uniform oscillations and finite-wavelength oscillatory modes.
A PIECEWISE LINEAR ELECTRONIC CIRCUIT WITH A MULTIPLICITY OF BIFURCATIONS
Authors: FREIRE EMILIO , PONCE ENRIQUE , RODRIGO FRANCISCO , TORRES FRANCISCO
Published: March 2005

Some theoretical bifurcation results previously obtained by the authors are applied to describe the bifurcation set of a piecewise linear electronic circuit with two state variables. The circuit under study was proposed, in a slightly more general version, in 1983 by J. P. Keener to simulate a finite dimensional formulation of the Fitzghugh–Nagumo equations in a piecewise linear approach. Three parameters are needed to unfold all the possible bifurcations that give rise to a multiplicity of dynamical behaviors.
PATIENT PERCEPTIONS OF THE QUALITY OF HEALTH SERVICES
Authors: Sofaer Shoshanna , Firminger Kirsten
Published: March 2005

▪ Abstract  As calls are made for a more patient-centered health care system, it becomes critical to define and measure patient perceptions of health care quality and to understand more fully what drives those perceptions. This chapter identifies conceptual and methodological issues that make this task difficult, including the confusion between patient perceptions and patient satisfaction and the difficulty of determining whether systematic variations in patient perceptions should be attributed to differences in expectations or actual experiences. We propose a conceptual model to help unravel these knotty issues; review qualitative studies that report directly from patients on how they define quality; provide an overview of how health plans, hospitals, physicians, and health care in general are currently viewed by patients; assess whether and how patient health status and demographic characteristics relate to perceptions of health care quality; and identify where further, or more appropriately designed, research is needed.

Our aim is to find out what patients want, need and experience in health care, not what professionals (however well-motivated) believe they need or get.

Through the Patient's Eyes ( 23 )
POPULATION DISPARITIES IN ASTHMA
Authors: Gold Diane R. , Wright Rosalind
Published: March 2005

▪ Abstract  The prevalence of asthma in the United States is higher than in many other countries in the world. Asthma, the most common chronic disease of childhood in the United States, disproportionately burdens many socioeconomically disadvantaged urban communities. In this review we discuss hypotheses for between-country disparities in asthma prevalence, including differences in “hygiene” (e.g., family size, use of day care, early-life respiratory infection exposures, endotoxin and other farm-related exposures, microbial colonization of the infant bowel, exposure to parasites, and exposure to large domestic animal sources of allergen), diet, traffic pollution, and cigarette smoking. We present data on socioeconomic and ethnic disparities in asthma prevalence and morbidity in the United States and discuss environmental factors contributing to asthma disparities (e.g., housing conditions, indoor environmental exposures including allergens, traffic air pollution, disparities in treatment and access to care, and cigarette smoking). We discuss environmental influences on somatic growth (low birth weight, prematurity, and obesity) and their relevance to asthma disparities. The relevance of the hygiene hypothesis to the U.S. urban situation is reviewed. Finally, we discuss community-level factors contributing to asthma disparities.
ACCULTURATION AND LATINO HEALTH IN THE UNITED STATES: A Review of the Literature and its Sociopolitical Context
Authors: Lara Marielena , Gamboa Cristina , Kahramanian M. Iya , Morales Leo S. , Hayes Bautista David E.
Published: March 2005

▪ Abstract  This chapter provides an overview of the concept of acculturation and reviews existing evidence about the possible relationships between acculturation and selected health and behavioral outcomes among Latinos. The effect of acculturation on Latino health is complex and not well understood. In certain areas—substance abuse, dietary practices, and birth outcomes—there is evidence that acculturation has a negative effect and that it is associated with worse health outcomes, behaviors, or perceptions. In others—health care use and self-perceptions of health—the effect is mostly in the positive direction. Although the literature, to date, on acculturation lacks some breadth and methodological rigor, the public health significance of findings in areas in which there is enough evidence justifies public health action. We conclude with a set of general recommendations in two areas—public health practice and research—targeted to public health personnel in academia, community-based settings, and government agencies.
17β-Estradiol enhances heparin-binding epidermal growth factor-like growth factor production in human keratinocytes
Authors: Kanda Naoko , Watanabe Shinichi
Published: March 2005

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) enhances reepithelialization in wounds. Estrogen is known to promote cutaneous wound repair. We examined the in vitro effects of 17β-estradiol (E2) on HB-EGF production by human keratinocytes. E2 or membrane-impermeable BSA-conjugated E2 (E2-BSA) increased HB-EGF secretion, mRNA level, and promoter activity in keratinocytes. E2 or E2-BSA enhanced in vitro wound closure in keratinocytes, and the closure was suppressed by anti-HB-EGF antibody. Activator protein-1 (AP-1) and specificity protein 1 (Sp1) sites on HB-EGF promoter were responsible for the E2- or E2-BSA-induced transactivation. Antisense oligonucleotides against c-Fos, c-Jun, and Sp1 blocked E2- or E2-BSA-induced HB-EGF transactivation. E2 or E2-BSA enhanced DNA binding and transcriptional activity of AP-1 and generated c-Fos/c-Jun heterodimers by inducing c-Fos expression. E2 or E2-BSA enhanced DNA binding and transcriptional activity of Sp1 in parallel with the enhancement of Sp1 phosphorylation. These effects of E2 or E2-BSA were not blocked by the nuclear estrogen receptor antagonist ICI-182,780 or anti-estrogen receptor-α or -β antibodies but were blocked by inhibitors of G protein, phosphatidylinositol-specific PLC, PKC-α, and MEK1. These results suggest that E2 or E2-BSA may enhance HB-EGF production via activation of AP-1 and Sp1. These effects of E2 or E2-BSA may be dependent on membrane G protein-coupled receptors different from nuclear estrogen receptors and on the receptor-mediated activities of phosphatidylinositol-specific PLC, PKC-α, and MEK1. E2 may enhance wound reepithelialization by promoting HB-EGF production in keratinocytes.
Involvement of NH2 terminus of PKC-δ in binding to F-actin during activation of Calu-3 airway epithelial NKCC1
Authors: Smallwood Nicole D. , Hausman Bryan S. , Wang Xiangyun , Liedtke Carole M.
Published: March 2005

Direct binding of nonmuscle F-actin and the C2-like domain of PKC-δ (δC2-like domain) is involved in hormone-mediated activation of epithelial Na-K-2Cl cotransporter isoform 1 (NKCC1) in a Calu-3 airway epithelial cell line. The goal of this study was to determine the site of actin binding on the 123-amino acid δC2-like domain. Truncations of the δC2-like domain were made by restriction digestion and confirmed by nucleotide sequencing. His6-tagged peptides were expressed in bacteria, purified, and analyzed with a Coomassie blue stain for predicted size and either a 6xHis protein tag stain or an INDIA His6 probe for expression of the His6 tag. Truncated peptides were tested for competitive inhibition of binding of activated, recombinant PKC-δ with nonmuscle F-actin. Peptides from the NH2-terminal region, but not the COOH-terminal region, of the δC2-like domain blocked binding of activated PKC-δ to F-actin. The δC2-like domain and three NH2-terminal truncated peptides of 17, 83, or 108 amino acids blocked binding, with IC50 values ranging from 1.2 to 2.2 nmol (6–11 μM). NH2-terminal δC2-like peptides also prevented methoxamine-stimulated NKCC1 activation and pulled down endogenous actin from Calu-3 cells. The proximal NH2 terminus of the δC2-like domain encodes a β1-sheet region. The amino acid sequence of the actin-binding domain is distinct from actin-binding domains in other PKC isotypes and actin-binding proteins. Our results indicate that F-actin likely binds to the β1-sheet region of the δC2-like domain in airway epithelial cells.
Effect of temperature on spike-triggered average torque and electrophysiological properties of low-threshold motor units
Authors: Farina Dario , Arendt-Nielsen Lars , Graven-Nielsen Thomas
Published: March 2005

The aim of the study was to jointly analyze temperature-induced changes in low-threshold single motor unit twitch torque and action potential properties. Joint torque, multichannel surface, and intramuscular electromyographic signals were recorded from the tibialis anterior muscle of 12 subjects who were instructed to identify the activity of a target motor unit using intramuscular electromyographic signals as feedback. The target motor unit was activated at the minimum stable discharge rate in seven 3-min-long contractions. The first three contractions (C1–C3) were performed at 33°C skin temperature. After 5 min, the subject performed three contractions at 33°C (T1), 39°C (T2), and 45°C (T3), followed by a contraction at 33°C (C4) skin temperature. Twitch torque and multichannel surface action potential of the target motor unit were obtained by spike-triggered averaging. Discharge rate (mean ± SE, 7.1 ± 0.5 pulses/s), interpulse interval variability (35.8 ± 9.2%), and recruitment threshold (4.5 ± 0.4% of the maximal voluntary torque) were not different among the seven contractions. None of the investigated variables were different among C1–C3, T1, and C4. Conduction velocity and peak twitch torque increased with temperature ( P < 0.05; T1: 3.53 ± 0.21 m/s and 0.82 ± 0.23 mN·m, T2: 3.93 ± 0.24 m/s and 1.17 ± 0.36 mN·m, T3: 4.35 ± 0.25 m/s and 1.46 ± 0.40 mN·m, respectively). Twitch time to peak and surface action potential peak-to-peak amplitude were smaller in T3 (61.8 ± 2.0 ms and 27.4 ± 5.1 μV, respectively) than in T1 (71.9 ± 4.1 ms and 35.0 ± 6.5 μV, respectively) ( P < 0.05). The relative increase in conduction velocity between T1 and T3 was positively correlated ( P < 0.05) with the increase in twitch peak amplitude ( r2 = 0.48), with the decrease in twitch time to peak ( r2 = 0.43), and with the decrease in action potential amplitude ( r2 = 0.50). In conclusion, temperature-induced modifications in fiber membrane conduction properties may have a direct effect on contractile motor unit properties.
Changes in mineralization and biomechanics of tibial metaphyses in splinted rats
Authors: Lentle R. G. , Kruger M. C.
Published: March 2005

The effect of 3 wk of splintage of a single hindlimb on the midarea and mineral content of both tibial metaphyses was assessed immediately after splint removal and after 1 mo of mobilization in 12-wk-old Sprague-Dawley rats. Immobilization reduced tibial metaphyseal bone mineral density (BMD) in immobilized limbs compared with “free” limbs of splinted animals and with controls. These changes persisted and were accentuated by relatively greater increases in tibial metaphyseal BMDs of unsplinted (control) animals after 7 wk. Immediately after splintage, tibial metaphyseal areas and total mineral contents of both hindlimbs of splinted animals were reduced compared with those of unsplinted animals. However, the relationship between mineralization and area differed between the free and immobilized limbs of splinted animals. The breaking strain and the breaking energy of immobilized and free femurs of splinted animals were impaired 4 wk after the removal of the splint. This impairment was correlated with an effect of splintage on femoral size with some additional local effect from immobilization. Thus osteoporotic changes consequent on immobilization include both local effects on mineralization and general effects on growth, which may separately influence the elastic properties of bone.
The Insulin-Like Growth Factor I Generation Test in Adults
Authors: Lissett Catherine A. , Gleeson Helena , Shalet Stephen M.
Published: March 2005

The insulin-like growth factor I (IGF-I) generation test has the potential to assess the ability of an individual to respond to an acute bolus of growth hormone (GH), in terms of IGF-I, IGF-binding protein 3 and acid-labile subunit responses. This article will discuss something of the history of the IGF-I generation test, and review some of the major studies to date. The IGF-I generation test was first used in adults by Lieberman et al., who studied the effects of ageing and oestrogen administration, and suggested that decreased responsiveness to GH occurs with increasing age and oral oestrogen administration. Our results, however, show that, while activity of the GH/IGF-I axis declines with age, peripheral responsiveness to GH is not affected. As in the Lieberman study, we found that oral oestrogen replacement reduces responses of GH-dependent peptides to GH stimulation in healthy post-menopausal women. Transdermal oestrogen administration also reduced responsiveness to GH, although to a lesser degree than orally administered oestrogen. In addition, utilizing a non-weight-based dose of GH we have demonstrated that obese individuals produce greater increases in IGF-I following an acute bolus of GH. In GH deficiency (GHD), data suggesting enhanced peripheral responsiveness should be interpreted with caution, and with awareness of differences between these groups in terms of age and obesity. The IGF-I generation test may allow a fresh approach to unanswered questions in the field of GHD, but as the IGF-I response to GH is not strictly associated with protein anabolism or clinical benefit, the question remains whether this test will predict the effect of longer-term GH administration.
Effects of Fat-Modified Dairy Products on Blood Lipids in Humans in Comparison with Other Fats
Authors: Seidel Christiane , Deufel Thomas , Jahreis Gerhard
Published: March 2005

Background/Aim: Due to its high content of LDL-raising saturated fatty acids (SFA), milk fat has been considered to be hypercholesterolaemic, but it also contains fatty acids and other constituents which seem to have a hypocholesterolaemic effect. Milk fat was modified by feeding cows rapeseed cake, resulting in a reduced content of SFA and an increased content of unsaturated fatty acids. The objective of this study was to investigate the effects of modified milk fat (ModFat) on serum cholesterol fractions, triacylglycerides (TAG) and lipoprotein(a) [LP(a)], compared with regular milk fat (RegFat) and with soft margarine (Marg). Method: Fifteen women and 16 men were enrolled in the intervention study. Nine of the participants were hypercholesterolaemic. Nutrient intake parameters, serum lipids and LP(a) were determined. Results: The serum concentration of HDL cholesterol increased in the ModFat period, leading to a decreased LDL/HDL ratio in this period. The lowest LP(a) concentrations were measured at the end of the control phase and at the end of the ModFat period. A decreasing tendency of serum TAG concentration was observed in the ModFat period. Conclusion: The fat-modified milk seems to have positive effects on the LDL/HDL ratio and the LP(a) concentrations, both of which have been established as risk factors for coronary heart disease.
Effect of Steroidal and Non-Steroidal Drugs on the Microglia Activation Pattern and the Course of Degeneration in the Retinal Degeneration Slow Mouse
Authors: Sarra G.M. , Sarra F.G. , Schlichtenbrede F.C. , Trittibach P. , Estermann S. , Tsiroukis E. , Ali R.R. , Luthert P.J. , Reichel M.B.
Published: March 2005

Background: In hereditary retinal degeneration, microglia cells become activated, migrate through the outer nuclear layer (ONL) and accumulate in the subretinal space. Although this inflammatory process is not likely to be responsible for the onset of photoreceptor apoptosis, cytotoxic substances secreted by activated microglia could potentially accelerate and perpetuate the degenerative process. Anti-inflammatory drugs have been shown to modulate the microglia response in neurodegenerative disorders and potentially ameliorate the disease progression in various animal model systems. In this study we wanted to test the impact of the most commonly used anti-inflammatory drugs (acetylsalicylate and prednisolone) on the microglia activation pattern, the rate of caspase-3-dependent photoreceptor apoptosis and the course of the degeneration in the retinal degeneration slow (rds) mouse retina. Methods: 169 pigmented rds mice and 30 CBA wild-type mice were used for this study. The treatment groups were injected daily with either acetylsalicylate (200 mg/kg) or prednisolone (2 mg/kg) i.p. from day 0 up to 3 months. Animals were sacrificed at days 10, 14, 16, 18, 20, 30, 40, 60 and 90. Cryoprotected frozen sections were immunostained with F4/80 and cleaved caspase-3 antibodies. The main outcome measures were the total microglia count in the subretinal space, the total cleaved caspase-3-positive cells in the ONL and the averaged number of photoreceptor rows in the midperipheral retina. Results: Neither acetylsalicylate nor prednisolone reduced subretinal microglia accumulation in the rds mouse degeneration model. Moreover, they aggravated migration and accumulation in the early time course. The apoptotic cascade started earlier and was more pronounced in both treatment groups compared to the control group. The pace of retinal degeneration was not reduced in the treatment groups compared to the untreated control. In contrast, acetylsalicylate did significantly accelerate the photoreceptor cell degeneration in comparison to the prednisolone (p < 0.001) and to the control group (p < 0.001). Conclusions: Acetylsalicylate and prednisolone do not decrease the microglia response in the rds mouse and are not neuroprotective. More research is needed to clarify the molecular mechanisms which lead to photoreceptor cell death and to elucidate the complex role of microglia in inherited retinal degeneration.
Cerebrospinal Fluid Leaks of Temporal Bone Origin: Etiology and Management
Authors: Stenzel Mark , Preuss Simon , Orloff Lisa , Jecker Peter , Mann Wolf
Published: March 2005

Background: Cerebrospinal fluid (CSF) leaks of the temporal bone region require surgical treatment as they pose life-threatening risks such as meningitis. Aim: The aim of the study was to determine the surgical outcome depending on different operation techniques and grafts. Method: We performed a retrospective review of 28 cases of CSF leaks, operated in our department from 1983 to 2002. After a mean follow-up of 8 years, patients were interviewed concerning otorrhea or rhinorrhea and meningitis. In this context, our management of CSF leaks is presented. Results: The CSF leak had arisen spontaneously (n = 3), traumatically (n = 6) or postoperatively (n = 19). The surgical CSF leak repairs were performed via a transmastoid (n = 13), a middle fossa (n = 11) or a combined (n = 4) approach. Surgical outcome was independent on the used graft. CSF leak could be sealed in 25 of 28 cases. Only 3 patients suffered from recurrences. Meningitis or other complications did not occur. Conclusions: Comparing different techniques and grafts, there were no differences in the surgical outcome.
Effect of High Glucose on Superoxide in Human Mesangial Cells: Role of Angiotensin II
Authors: Leehey David J. , Isreb Majd A. , Marcic Sonja , Singh Ashok K. , Singh Rekha
Published: March 2005

Background/Aims: Reactive oxygen species, and especially superoxide (O2·–),have been implicated in diabetic nephropathy. O2·– accumulation in cells is dependent on O2·– production (by NADH/NADPH oxidase) as well as scavenging by superoxide dismutase (SOD) activity. This study was designed to investigate the effects of high glucose (HG) on O2·– accumulation and SOD activity in human mesangial cells (HMC) and to determine if these effects are mediated by angiotensin II (Ang II). Methods: HMC were incubated in media containing 10 mMglucose (control, C), 30 mM glucose (HG), 10 mM glucose + either 20 mM 2-deoxy-D-glucose (2-DG) or 20 mM mannitol (high mannitol, HM) (osmotic controls), or Ang II (10–5M). Ang II action was antagonized by employing 10–4M of Ang II receptor antagonists (losartan or irbesartan) or 10–4M of NADH/NADPH oxidase inhibitors [diphenyleneiodonium chloride (DPI) or apocynin]. Superoxide and total SOD activity were assayed using chemiluminescence of lucigenin. Results: Incubation of HMC in HG resulted in a 1.6-fold increase in Ang I (p < 0.05) and a 1.4-fold increase in Ang II levels (p < 0.05) in cell lysates. These changes were accompanied by a >2-fold increase in O2·– accumulation (p < 0.01), which was inhibited by losartan and irbesartan. Exogenous Ang II increased net O2·– accumulation by 2.7-fold (p < 0.01), which was normalized by losartan and irbesartan. DPI and apocynin blocked the HG and Ang II-induced increases in O2·– (p < 0.01). HG but not exogenous Ang II inhibited total SOD activity by 30%, which was not affected by losartan. Conclusion: High glucose increases O2–· accumulation in HMC primarily by increasing its production via the Ang II-NADH/NADPH oxidase system.