bluuebunny/crossref_metadata_2025 huggingface dataset:
IMPACT OF ULTRAVIOLET‐B RADIATION ON PHOTOSYSTEM II ACTIVITY AND ITS RELATIONSHIP TO THE INHIBITION OF CARBON FIXATION RATES FOR ANTARCTIC ICE ALGAE COMMUNITIES1
Authors: Schofield Oscar , Kroon Bernd M. A. , Prézelin Barbara B.
Published: October 2004

One goal of the Icecolors 1993 study was to determine whether or not photosystem II (PSII) was a major target site for photoinhibition by ultraviolet‐B radiation (QUVB, 280–320 nm) in natural communities. Second, the degree to which QUVBinhibition of PSII could account for QUVBeffects on whole cell rates of carbon fixation in phytoplankton was assessed. On 1 October, 1993, at Palmer Station (Antarctica), dense samples of a frazil ice algal community were collected and maintained outdoors in the presence or a bsence of QUVBand l or ultraviolet‐A (QUVB, 320–400 nm) radiation. Samples were then collected at intervals over the day to track the time course of UV inhibition of primary production. The ice algae were assessed for changes in pigment composition and rates of carbon fixation. The quantum yield of PSII (ØIIc°) was measured by Pulse Amplitude Modulated fluorometry. Over the day, ØIIc° declined due to increasing time‐integrated dose exposure of QUVB. The QUVB‐driven inhibition of ØIIc° increased from 4% in the early morning hours to a maximum of 23% at the end of the day. The QUVB photoinhibition of PSII quantum yield did not recover by 6 h after sunset. In contrast, photoinhibition by QUVA and photosynthetically available radiation (QPAR, 400–700 nm) recovered during the late afternoon. Flourescence‐based estimates of carbon fixation rates were linearly correlated (P =0.002, r2=0.45) with measured carbon fixation. Fluorescence overestimated the observed QUVB inhibition in measured carbon fixation rates by 8% in the morning hours; however, the discrepancy increased during the afternoon. Therefore, researchers should be cautious in using fluorescence measurements to infer ultraviolet inhibition for rates of carbon fixation until there is a greater understanding of the coupling of carbon metabolism to PSII activity for natural populations. Despite these current limitations, fluorescence‐based technologies represent powerful tools for studying the impact of the ozone hole on natural populations on spatial/ temporal scales not possible using conventional productivity techniques.
DIFFUSION BOUNDARY LAYER TRANSPORT IN GRACILARIA CONFERTA (RHODOPHYTA)1
Authors: Gonen Yael , Kimmel Eitan , Friedlander Michael
Published: October 2004

A theoretical framework on the combined effect of water velocity and solute concentration on the photosynthetic performance of the red alga Gracilaria conferta (Rhodophyta) is developed. This is based on the balance between the rate of transport through boundary layers and Michaelis‐Menten‐type equations for carbon consumption and for production of oxygen and hydroxyl ions. By comparing the theoretical models with experimental data, we found that the mechanism of enhancing photosynthetic rates by increasing water velocity cannot be attributed to enhanced bicarbonate and CO2 transport, nor to CO2 as a sole source of carbon. Velocity‐facilitated photosynthesis may be due to the enhanced removal of OH− ions, which inhibit photosynthesis when accumulated on the algal surface. Oxygen had no inhibitory effect on Gracilaria conferta.
STEROL, FATTY ACID, AND PIGMENT CHARACTERISTICS OF UTEX 2341, A MARINE EUSTIGMATOPHYTE IDENTIFIED PREVIOUSLY AS CHLORELLA MINUTISSIMA (CHLOROPHYCEAE)1
Authors: Gladu Patricia K. , Patterson Glenn W. , Wikfors Gary H. , Smith Barry C.
Published: October 2004

An examination of the sterols of UTEX 2341, a small (ca. 2μm), nonmotile unicellular marine alga identified as Chlorella minutissima Fott et Novakova, yielded results inconsistent with any of 35 Chlorella strains analyzed previously. UTEX 2341 contained cholesterol as the principal sterol, with 24‐methylenecholesterol, fucosterol, and isofucosterol also present; these are not dominant sterols in any other Chlorella species. Presence of eicosapentaenoic acid in UTEX 2341 also contrasted with fatty acids of Chlorella strains analyzed previously. Pigment analysis of UTEX 2341 revealed that it contained chlorophyll a, but not chlorophylls b or c; violaxanthin was the only major xanthophyll pigment. Both lipid and pigment compositions suggest that UTEX 2341 is not a member of the genus Chlorella but, rather, belongs in the Eustigmatophyceae; it may be Nannochloropsis sp. Cells with possible extracellular structures were present at an appreciable percentage of the stationary‐phase population studied; centrifuging removed or collapsed these structures. The high cholesterol and polyunsaturated fatty acid contents of UTEX 2341 make it attractive as a potential aquaculturefeed, provided it is, or can be made, digestible.
OPTIMIZATION OF AN IMMUNOFLUORESCENT ASSAY OF THE INTERNAL ENZYME RIBULOSE‐1,5‐BISPHOSPHATE CARBOXYLASE (RUBISCO) IN SINGLE PHYTOPLANKTON CELLS1
Authors: Orellana Mónica V. , Perry Mary Jane
Published: October 2004

Immunochemical probes are widely used to identih different species and to quantify and understand the role that different antigens play within cells. We optimized a single‐cell immunofluorescent assay for the carbon fixation enzyme ribulose‐1,5‐bisphosphate carboxylase (Rubisco) in order to quantify the enzyme by flow cytometry in phytoplankton cells. The criteria for optimization of the immunofluorescent assay for Rubisco in single cells included maximization of Rubisco immunogenicity, minimization of Rubisco diffusion out of the cells, minimization of cell breakage, and maximization of the cell labeling. Several fixatives (cross‐linkers and denaturing) and permeabilizing agents were tested on 26 species of phytoplankton. The only fixative / permeabilizing agent that fulfilled the criteria established for the assay was 96% ethanol. Phytoplankton cells collected from the field needed further treatment with a strong oxidant to permeabilize ethanolfixed cells and thus allow the antibody probe to access the Rubisco antigen. This study should have a general applicability to the study of other soluble photosynthetic antigens in single phytoplankton cells.
MORPHOSPECIES VS. GENOSPECIES IN TOXIC MARINE DINOFLAGELLATES: AN ANALYSIS OF GYMNODZNIUM CATENATUM/GYRODINIUM IMPUDICUM AND ALEXANDRIUM MINUTUM/A. LUSITANICUM USING ANTIBODIES, LECTINS, AND GENE SEQUENCES1
Authors: Costas Eduardo , Zardoya Rafael , Bautista Jose , Garrido Amando , Rojo Carmen , López‐Rodas Victoria
Published: October 2004

Morphological features are the predominant criteria used to define species of marine dinoflagellates. Taxonomic problems with some toxic groups has led to the implementation of molecular taxonomy techniques and development of a genospecies concept. As a result, the relationships between “morphospecies” and “genospecies” has been questioned. In this study, the genetic differentiation between two sets of closely related morphospecies, Gymnodinium catenatum Graham/Gyrodinium impudicum Fraga and Alexandrium minutum Halim/Alexandrium lusitanicum Balech, were analyzed. The extent of morphological differentiation existing within these two groups is of the same order of magnitude. Analysis of cell surface antigens detected by preadsorbed serum, cell surface glycan moieties detected by lectins and sequencing of the D9 and D10 domains of the Large‐subunit ribosomal RNA gene, showed that the extent of genetic differentiation existing between the dinofagellates Gymnodinium catenatum/Gyrodinium impudicum is substantial. Therefore, both morphological and genetic criteria resolve these organisms as two distinct entities. In contrast, Alexandrium minutum/Alexandrium lusitanicum were indistinguishable using the some suite of molecular markers. The findings demonstrated that classifications based on morphological criteria may be incongruous. On a practical level, molecular taxonomy provides useful tools to distinguish between morphologically similar microalgal species and furthermore can prevent misidentification of species such as Gymnodinium catenatum/Gyrodinium impudicum, a frequent occurrence when samples are fixed with Lugol's or formaldehyde solution.
ANALYSIS OF HETEROSIGMA CARTERAE1 (CHROMOPHYTA, RAPHIDOPHYCEAE) CHLOROPLAST rpoB GENE SEQUENCE2
Authors: Mangahas Jeff L. , Cattolico Rose Ann , Reynolds Ann E.
Published: October 2004

The rpoB gene encoding the β‐subunit of RNA Polymerase has been isolated from the chloroplast genome of the chromophytic alga Heterosigma carterae (Taylor 1992). The nucleotide sequence contains an open reading frame of 3348 bp, which encodes 1116 amino acids. The H. carterae rpoB gene structure is similar to that of chlorophytic chloroplast rpoB genes with respect to insertion‐deletion domains. However, several conserved residues found in all chlorophytic plants and bacterial rpoB genes have not been found in this alga. This is the first nonchlorophytic chloroplast rpoB gene to be analyzed, and our data provide insight concerning regions, and perhaps particular residues, that may be essential to chloroplast RNA polymerase function.
AN IN VITRO NITRATE REDUCTASE ASSAY FOR MARINE MACROALGAE: OPTIMIZATION AND CHARACTERIZATION OF THE ENZYME FOR FUCUS GARDNERI (PHAEOPHYTA)1
Authors: Hurd Catriona L. , Berges John A. , Osborne Josephine , Harrison Paul J.
Published: October 2004

Measurement of the activity of the enzyme nitrate reductase (NR) may provide a useful index of nitrogen metabolism in marine macroalgae. In several species, including Fucus gardneri P. C. Silva, in vitro assays previously failed to detect NR activity, necessitating the use of in situ (or so‐called“in vivo”) assays, which are more loosely controlled and lead to dafficulties in assessing enzyme characteristics such as the half‐saturation constant (Km). In this paper, we describe an in vitro NR assay developed for F. gardneri, in which tissue was homogenized using liquid nitrogen prior to the assay. In contrast to previous studies, enzyme activity was always detectable in F. gardneri collected directly from the field at levels up to 30 nmol nitrate converted to nitrite·min−1·g−1 wet weight. The effect of a variety of compounds, commonly added to NR extraction buffers, were tested. Additions of protease inhibitors, bovine serum albumin, and ethylenediamine tetraacetic acid had no consistent effects on NR activity, while polyvinyl pyrrolidone, potassium ferricyanide, and flavin adenine dinucleotide significantly decreased activity. The half‐saturation constant (Km) for NADH was 0.18 (± 0.05) mM and for nitrate, Km=0.99 (±0.41) mM. Significant NR activity was detected without the addition of nitrate, suggesting that internal pools of nitrate averaging approximately 20 μmol NO3−·g−1 wet weight were present in F. gardneri in February. The distribution of NR activity within the plant was highly variable between individuals, but activities were approximately 5‐fold lower in the stipe than in midregions. In plants freshly sampled from the field, NR activity increased 7‐fold from February to March, then fell to near‐February levels by April. These changes in activity may correspond to seasonal changes in growth rate. The assay, optimized for F. gardneri, was used in several different macroalgal species from different taxa: Porphyra sp., Coralina vancouveriensis Yendo, Ulva sp., Enteromorpha intestinalis (Linnaeus) Nees, Macrocystis integrifolia Bory; and Costaria costatum (C. Agardh) Saunders. For all species tested, NR activity was detectable and, except for one species (Porphya sp.), was equal to or greater than activities measured by other workers using in vivo or in vitro assays for plants under similar conditions.
EFFECT OF CURRENT VELOCITY ON THE DETACHMENT OF THALLI OF ULVA LACTUCA (CHLOROPHYTA) IN A NEW ZEALAND ESTUARY
Authors: Hawes Ian , Smith Rob
Published: October 2004

Experiments were undertaken in a recirculating flume to determine the relationships among water velocity, thallus area, drag, and the probability of thallus breakage or detachment in the foliose green alga Ulva lactuca L. In all specimens tested to breaking point, thalli detached from their bivalve substrates as a result of stipe breakage rather than in midthallus or by holdfast detachment. There was no relationship between thallus size and drag at which detachment occurred. Rather, the probability of detachment was normally distributed about a mean drag of 0. 70 N (95% confidence limits 0.55–0.85 N). Average breaking stress of stipes was 345 kN.m‐2 (95% cl 250–485 kN.m‐2). Similar results were obtained in field experiments where the horizontal force required to detach thalli was measured directly as 0.93 N (95% cl 0.69–1.15 N). Drag coefficients of plants were not constant with water velocity but increased up to 0.4 m.s‐1, declining exponentially at velocities above this. Empirical relationships were established between coefficient of drag and Reynold's number and, hence, among drag, thallus area and water velocity. These relationships permitted estimation of mean water velocity at which plants of a given area would detach.
GROWTH RESPONSES OF SEVERAL DIATOM SPECIES ISOLATED FROM VARIOUS ENVIRONMENTS TO TEMPERATURE
Authors: Suzuki Yoshihiro , Takahashi Masayuki
Published: October 2004

Eight diatom species(Chaetoceros pseudocurvisetusMang., Stephanodiscus hantzschiiGrun., Skeletonema costatum (Grev.) Cleve, Asterionella formosaHass., Thalassiosira nordenskioeldiiCleve, Detonula confervacea (Cleve) Gran, Chaetocerossp., andNitzschia frigidaGrun.) were isolated from various temperature environments ranging from temperate to the Arctic, and their growth responses to temperature were determined. Each species grew over a different temperature range. The lower and upper limits of each species varied from −1.8° to 20° C and from 2° to 30° C, respectively. The width of the growth range of each species. also varied from 3.8° to 25° C, and the growth of these species was observed, as a whole, between a wide temperature range from −1.8° to 30° C.

Within the growth temperature ranges, the growth rate of each species increased with temperature until reaching a maximum, which was followed by a steep decrease up to the upper limit of the growth range. As a result, each species showed a maximum rate at the temperature very near to the upper limit, which was generally higher than the isolation temperature. The specific growth rates were compared among the eight species. The interspecific maximum rate at each temperature exhibited an exponential increase with a Q10=1.48. The relative growth rates of each species were calculated by normalizing the specific growth rates with the interspecific maximum rate at each respective temperature. The higher relative growth rates tended to occur at the isolation temperature of each species, suggesting that temperature is a significant control on species distributions in nature.
INCORPORATION OF FRESHWATER RHODOPHYTA INTO THE CASES OF CADDISFLIES (TRICHOPTERA) FROM NORTH AMERICA
Authors: Sheath Robert G. , Müller Kirsten M. , Larson David J. , Cole Kathleen M.
Published: October 2004

Cases of larvae and pupae from six caddisfly (Insecta, Trichoptera) genera in three families from North America were observed to contain pieces of freshwater rhodophyte thalli. Seven genera of Rhodophyta, representing 13 species and 35 populations, were observed in this association. Four of the 25 species of Batrachospermum were incorporated into cases of Ochrotrichia (Hydroptilidae) and Agrypnia (Phryganeidae). Two of the three freshwater species of Bostrychia were used by Ochrotrichia larvae. Both Compsopogon coeruleus (Balbis) Mont. and C. prolificus Yadava et Kumano were present in the cases of Hydroptial (Hydroptilidae) and Ochrotrichia; Compsopogonopsis leptocladus (Mont.) Krishnamur‐thy was observed in the cases of Hydroptila. The more cartilaginous thalli of Lemanea fluviatilis (L.) C. Ag. and Tuomeya americana (Kütz.) Papenfuss were used by the brachycentrid larvae of Brachycentrus and Mi‐crasema. Lemanea and Paralemanea spp. were also in the cases of Dibusa angata Ross (Hydroptilidae). The architecture of each caddisfly case was studied with light and scanning electron microscopy. Strips of algae were fit together in a transverse, concentric, or spiralled fashion. Based on transmission electron micrographs, cortical cells of Lemanea and Tuomeya in the cases of Brachycentrus and Micrasema appeared to be healthy with intact chloroplasts and typical batrachospermalean pit plugs. Geographic distributions of each rhodophyte‐caddisfly association are given.
MOLECULAR STRUCTURE AND EVOLUTION OF THE CHLOROPLAST atpB/E GENE CLUSTER IN THE DIATOM ODONTELLA SINENSIS
Authors: Kroth‐Pancic Peter G. , Freier Ulrich , Strotmann Heinrich , Kowallik Klaus V.
Published: October 2004

We cloned and sequenced the chloroplast atpB/E gene cluster encoding the β‐ and εsubunits of the chloroplast ATPase, together with its flanking regions, in the centric diatom Odontella sinensis (Grev.) Grunow. This gene cluster, which was transcribed into a main transcript of 3.5 kb, was flanked by the genes ycf 3 (upstream atpB) and ORF 263 (downstream atpE), the latter being unknown from land plant chloroplasts. All reading frames were located on the same strand. In contrast to most higher plants, atpB and atpE in Odontella sinensis did not overlap but were separated from each other by 13 nucleotides (nts), similar to other chlorophyll a+c‐containing algae. Comparisons of atpB/E spacer regions from cyanobacteria, algae, and land plants indicate that separated atpB and atpE genes reflect a primitive rather than derived character. The spacer separating atpE and ORF 263 contained an inverted repeat sequence of 14 nts. Comparisons of inferred amino acid sequences from atpB of Odontella with known ATPase‐β sequences from other photosynthetic organisms revealed 75–91% identical amino acid residues. In contrast, the εsubunits exhibited 26–65% protein sequence conservation, with sequence identities around 40% within chlorophyll a+c‐containing algae. Relative to β‐subunits ofchlorophjtes (including land plants) and cyanobacteria, a gap of four amino acid residues was found close to the N‐terminus of ATPase‐β in Odontella. Phylogenetic trees constructed by maximum parsimony and distance matrix methods were consistent with a monophyletic origin of all extant plastid types from within the cyanobacterial radiation, but did not unequivocally delineate evolutionary affiliations among nongreen plastids.
USINGrbcL SEQUENCES TO TEST HYPOTHESES OF CHLOROPLAST AND THALLUS EVOLUTION IN CONJUGATING GREEN ALGAE (ZYGNEMATALES, CHAROPHYCEAE)
Authors: McCourt Richard M. , Karol Kenneth G. , Kaplan Susanne , Hoshaw Robert W.
Published: October 2004

Sequences for the Rubisco large subunit (rbcL) gene were used to test hypotheses about the evolution of chloroplast shape and thallus type in genera of two families of conjugating green algae (Zygnematales): the Mesotaeniaceae (saccoderm desmids, mostly unicellular) and the Zygnemataceae (strictly filamentous). Unicellular (u) and filamentous (f) genera exhibit a series of three similar chloroplast shapes: ribbonlike (e.g. Spirotaenia [u], Spirogyra [f], and Sirogonium [f], laminate (e.g. Mesotaenium [u] and Mougeotia [f]), and twin‐stellate (e.g. Cylindrocystis [u] and Zygnema [f]. Two conflicting phylogenetic hypotheses have been proposed: 1) families are polyphyletic constructs drawn from three lineages, each with unicellular and filamentous taxa characterized by a specific chloroplast shape; or 2) unicells form one monophyletic lineage (Mesotaeniaceae) and filaments form another (Zygnemataceae), with some chloroplast shapes independently derived. The rbcL data strongly refute hypothesis 2 (monophyly of the two traditional families) and support hypothesis 1 in part. Parsimony, maximum likelihood, and neighbor‐joining analyses of the rbcL data strongly support monophyly of a clade containing taxa with ribbonlike chloroplasts and, to a lesser extent, monophyly of a second clade of the four genera with the other two chloroplast shapes. Two saccoderm genera (Roya, curved laminate chloroplasts; Netrium, “cucumber”‐shaped chloroplasts) are not members of either of these clades, but they are included in a monophyletic Zygnematales.
Modelling the spatial dynamics and persistence of the leaf beetle Gonioctena olivacea in dynamic habitats
Authors: Biedermann Robert
Published: October 2004

In dynamic landscapes natural and anthropogenic disturbance as well as succession are responsible for the emergence and subsequent disappearance of suitable habitat patches. Species inhabiting such landscapes are faced with varying number and spatial configuration of patches. A stochastic, spatially explicit simulation model was developed in order to analyse the persistence of the leaf beetle Gonioctena olivacea in a system of dynamic patches of its host plant Cytisus scoparius. The model was parameterized with data from a three‐year field study on the spatial configuration, distribution, and turnover of the host plant patches as well as the patch occupancy, extinction, and colonization rates of the beetle. The simulations showed large fluctuations in the occurrence of the beetle in the patches. High levels of occupancy were related to high aggregation of the patches within the landscape. The velocity of patch turnover was found to have a severe effect on the persistence of the beetle metapopulation. Enhancing the turnover rate by only a few patches, the mean time to extinction decreases rapidly. Moreover, the results revealed that not necessarily an effect of connectivity can be detected in the analysis of occupancy patterns in dynamic landscapes, although the colonization of patches is clearly connectivity‐dependent. In general, this modelling study demonstrates the importance of detailed information on patch turnover. The amount and spatial distribution of suitable habitat is a major driver of metapopulation dynamics of species in dynamic landscapes.
Generational interaction and social change in Pakistan
Authors: Bolognani Marta
Published: October 2004

Pakistan Workshop 2004, The Rook Howe, Cumbria, 7‐9 May 2004
The prevalence of injecting drug use in a Russian city: implications for harm reduction and coverage
Authors: Platt Lucy , Hickman Matthew , Rhodes Tim , Mikhailova Larissa , Karavashkin Victor , Vlasov Alexander , Tilling Kate , Hope Vivian , Khutorksoy Mikhail , Renton Adrian
Published: October 2004

Aim  This study sought to estimate the prevalence of injecting drug users (IDU) in Togliatti city and to examine the implications of these estimates for HIV prevalence and harm reduction.

Design  Routine data sources of IDUs were identified. Covariate capture–recapture techniques were used on the individuals identified on the three data sources and used to estimate the number of IDU ‘not observed’ by the data sources, and thereby estimate the prevalence of IDU.

Setting  Togliatti City, Samara Oblast, Russian Federation.

Participants  IDUs recorded on three data sources (narcology records, HIV positive test results and police arrest data) during 2001.

Measurements  Poisson regression models were fitted to the observed data, with interactions between data sources fitted to replicate ‘dependencies’ between those data sources. To select the best model the goodness of fit was approximated by χ2 distribution and the best‐fitting model was selected on the basis of standard information criteria and log likelihood ratio tests.

Findings  The total estimated population of IDUs is 20 226 [95% confidence interval (CI): 16 971–24 749] giving a population prevalence of 5.4% (95% CI: 4.5–6.6%) of the registered population and 2.7% (95% CI: 2.4–3.5%) of the population (including migrants) aged 15–44 years. For every one IDU in contact with a service there were three out of contact.

Conclusions  There  is  a  high  prevalence  of  IDU  which,  in  the  context  of  a fast‐emerging IDU‐associated HIV epidemic, will have serious public health implications.
Adherence to pharmacotherapy in patients with alcohol and opioid dependence
Authors: Weiss Roger D.
Published: October 2004

Aims  An important factor that has thus far limited the effectiveness of pharmacotherapies for patients with alcohol and opioid dependence is poor adherence to medication regimens. This paper presents a review of issues related to medication adherence in patients with these substance use disorders.

Design and methods  A literature review was conducted of English language publications relating to medication adherence among patients with alcohol or opioid dependence.

Findings  The paper places the topic in the context of adherence difficulties among patients with a variety of chronic medical and psychiatric illnesses. Difficulties measuring adherence are discussed, and strategies to improve medication adherence are reviewed. These include specific interventions that prescribing clinicians can implement in their individual meetings with patients; the use of external reinforcers, such as positive and negative contingencies, and involvement of family members or significant others; and specific prescribing and dosing practices that may improve adherence.

Conclusions  As the use of pharmacotherapy for substance‐dependent patients increases, rigorous and innovative approaches to encourage medication adherence should be sought.
The Bohr effect of haemoglobin in vertebrates: an example of molecular adaptation to different physiological requirements
Authors: Giardina B. , Mosca D. , De Rosa M. C.
Published: October 2004

The Bohr effect, i.e. the pH dependence of the oxygen affinity of haemoglobins (Hbs) from a variety of vertebrates, and its modulation by temperature and other heterotropic effectors has been reviewed. Haemoglobins from vertebrates were not reviewed following the usual classification (i.e. mammals, birds, etc.); instead we have selected several key examples of animals, which are confronted with a similar environmental situation therefore displaying a similar life style. Hence, the paper starts from a description of the general concepts at the basis of the Bohr effect as exemplified by human HbA and goes towards the analysis of the modulation mechanisms which have been observed in different animals in response to the needs induced by: (i) life in cold environments; (ii) diving behaviour; (iii) flight; and (iv) aquatic life. The emerging picture indicates a complex organization of the information contained in the Hb molecule, the oxygen‐binding properties of which depend both on the intrinsic characteristics of the protein and on its heterotropic interactions with ligands such as protons (Bohr effect), small anions like chloride and organic phosphates. In addition, each one of the functional effects induced by binding of a given effector appears to be under the strict control of temperature that enhances or decreases its relative weight with respect to all the others. It is just by this sophisticated network of interactions that the Hb molecule is able to satisfy the physiological requirements of a multitude of organisms without changing dramatically its quaternary structure.
Red blood cell pH, the Bohr effect, and other oxygenation‐linked phenomena in blood O2 and CO2 transport
Authors: Jensen F. B.
Published: October 2004

Abstract The discovery of the S‐shaped O2 equilibrium curve and the Bohr effect in 1904 stimulated a fertile and continued research into respiratory functions of blood and allosteric mechanisms in haemoglobin (Hb). The Bohr effect (influence of pH/CO2 on Hb O2 affinity) and the reciprocal Haldane effect (influence of HbO2 saturation on H+/CO2 binding) originate in the Hb oxy–deoxy conformational change and allosteric interactions between O2 and H+/CO2 binding sites. In steady state, H+ is passively distributed across the vertebrate red blood cell (RBC) membrane, and intracellular pH (pHi) changes are related to changes in extracellular pH, Hb‐O2 saturation and RBC organic phosphate content. As the Hb molecule shifts between the oxy and deoxy conformation in arterial‐venous gas transport, it delivers O2 and takes up CO2 and H+ in tissue capillaries (elegantly aided by the Bohr effect). Concomitantly, the RBC may sense local O2 demand via the degree of Hb deoxygenation and release vasodilatory agents to match local blood flow with requirements. Three recent hypotheses suggest (1) release of NO from S‐nitroso‐Hb upon deoxygenation, (2) reduction of nitrite to vasoactive NO by deoxy haems, and (3) release of ATP. Inside RBCs, carbonic anhydrase (CA) provides fast hydration of metabolic CO2 and ensures that the Bohr shift occurs during capillary transit. The formed H+ is bound to Hb (Haldane effect) while HCO3− is shifted to plasma via the anion exchanger (AE1). The magnitude of the oxylabile H+ binding shows characteristic differences among vertebrates. Alternative strategies for CO2 transport include direct HCO3− binding to deoxyHb in crocodilians, and high intracellular free [HCO3−] (due to high pHi) in lampreys. At the RBC membrane, CA, AE1 and other proteins may associate into what appears to be an integrated gas exchange metabolon. Oxygenation‐linked binding of Hb to the membrane may regulate glycolysis in mammals and perhaps also oxygen‐sensitive ion transport involved in RBC volume and pHi regulation. Blood O2 transport shows several adaptive changes during exposure to environmental hypoxia. The Bohr effect is involved via the respiratory alkalosis induced by hyperventilation, and also via the pHi change that results from modulation of RBC organic phosphate content. In teleost fish, β‐adrenergic activation of Na+/H+ exchange rapidly elevates pHi and O2 affinity, particularly under low O2 conditions.
Positive inotropic and sustained anti‐β‐adrenergic effect of diadenosine pentaphosphate in human and guinea pig hearts. Role of dinucleotide receptors and adenosine receptors
Authors: Arvola L. , Bertelsen G. , Hassaf D. , Ytrehus K.
Published: October 2004

Aim:  Diadenosine polyphosphates are present intracellularly and in extracellular fluid due to release from secretory vesicles in platelets, chromaffin cells and other cells. This study investigates effects of diadenosine pentaphosphate (AP5A) on heart muscle function.

Methods:  Contractile force amplitude and action potential duration at 90% repolarization (APD90) were measured after challenge with AP5A 50 μm or isoproterenol 50–70 nM in guinea pig papillary muscles. Isoproterenol was given immediately after AP5A‐exposure or after 45 min washout. AP5A was combined with antagonists to the purinergic P2 receptor (suramin 100 μm), the dinucleotide receptor [diinosine pentaphosphate 30 μm (IP5I)] or adenosine receptors [8‐(P‐sulfophenyl) theophylline 50 μm (8‐SPT)].

Results:  Results are %‐change (mean ± SEM) from value before exposure. AP5A increased contractile force by 22 ± 3%* (*P < 0.05), and IP5I abolished this. AP5A prolonged APD90 by 7 ± 2%*. AP5A significantly reduced response to isoproterenol acutely from 31 ± 4* (controls) to 9 ± 4% and after 45 min washout from 61 ± 14* (controls) to 16 ± 5%. 8‐SPT abolished the sustained effect. Increase in contractile force by AP5A was confirmed in human atria trabecula preparations.

Conclusion: AP5A increased contractile force and prolonged APD90. Contractile force increased by stimulation of the dinucleotide receptor in guinea pig myocardium. The sustained anti‐β‐adrenergic effect of AP5A was due to adenosine receptor stimulation.
Review article: relief of symptoms in gastric acid‐related diseases – correlation with acid suppression in rabeprazole treatment
Authors: Miner P.
Published: October 2004

Symptom relief is one of the key goals in the management of gastric acid‐related disorders such as gastro‐oesophageal reflux disease (GERD), including nonerosive reflux disease (NERD), and duodenal and gastric ulcer. Whereas heartburn and regurgitation are classic symptoms of GERD, duodenal and gastric ulcers are associated with epigastric pain. The relationship between gastric acid and the presence of symptoms correlates well in GERD and duodenal ulcer, but not in gastric ulcer and NERD. Nevertheless, in all these disorders, gastric acid is considered a key pathogenic element, and acid suppression remains central to therapy. With their profound, prolonged effect on acid inhibition, proton pump inhibitors are considered the first‐choice therapy for these disorders. Rabeprazole is a newer generation proton pump inhibitor that suppresses the gastric proton pump and acid secretion more rapidly than does omeprazole, lansoprazole or pantoprazole. In clinical trial settings, rabeprazole provided fast and sustained symptom relief, which can help ensure patient acceptance of therapy and aid in patient compliance.
Hope, health work and quality of life in families of stroke survivors
Authors: Bluvol Anna , Ford‐Gilboe Marilyn
Published: October 2004

Aim. This paper reports a study to examine the relationships among hope, family health promotion, and quality of life after stroke, by testing hypotheses derived from the Developmental Model of Health and Nursing.

Background. Little attention has been given to the influences of family strengths on health promotion behaviours and quality of life after stroke. The majority of studies have focused on stroke survivors, not their spouses.

Method. A descriptive, correlational study was carried out with 40 families of stroke survivors with moderate to severe functional impairments and their spouses. Both partners completed the Herth Hope Index (measure of hope), the Health Options Scale (measure of health work), the Reintegration to Normal Living Index (measure of quality of life) and a demographic questionnaire.

Results. For both partners, moderate, positive relationships were found between hope and health work (r = 0·52,r = 0·39,P < 0·01) and between hope and quality of life (r = 0·59,r = 0·32,P < 0·05). Family health work was positively associated with quality of life of stroke survivors (r = 0·50,P ≤ 0·001), but not their spouses. Spouses’ employment status, number of supports and functional independence at discharge predicted 40·6% and 46·3% of the variance in quality of life for stroke survivors and spouses, respectively, with the combination of hope and health work contributing an additional 17·8% in predicting stroke survivors’ quality of life but no additional variance to the prediction of spouses’ quality of life.

Conclusion. Theoretical relationships of the Developmental Model of Health and Nursing were supported for stroke survivors, but the model was less useful in explaining spouses’ experiences of hope, health work and quality of life. Findings provide direction for identifying ‘at risk’ families and raise awareness of the contribution of caregiver burden to quality of life in families of stroke survivors.
Experiences of infant‐feeding decision‐making among urban economically disadvantaged pregnant adolescents
Authors: Wambach Karen A. , Koehn Mary
Published: October 2004

Aim.  The aim of this paper is to report a pilot study of influencing factors in disadvantaged urban pregnant adolescents’ decision‐making about infant‐feeding choices.

Background.  Research related to decision‐making among adolescents indicates that attitudinal, social, perceived control, and commitment factors are influential in choosing and initiating breast‐ or bottle‐feeding. However, there is a need for further description of decision‐making processes in disadvantaged teenagers before intervention research is done.

Methods.  Focus group interviews with the Theory of Planned Behavior guiding the questioning were used with 14 pregnant adolescents between 18 and 39 weeks of gestation and between the ages of 14 and 18 in two obstetric clinics in Midwestern USA urban teaching hospitals. The majority of adolescents were African‐American and primiparae.

Findings.  The experiences of infant‐feeding decision‐making among pregnant adolescents were captured by two major themes: benefits vs. barriers of breastfeeding and bottle‐feeding, and independent choice vs. social influences. A common thread in these themes was ambivalence and uncertainty. The adolescents had both positive and negative attitudes toward methods, with many expressing their desire to combine breast‐ and bottle‐feeding. Many reported the health benefits of breastfeeding, yet identified barriers of pain, public exposure, and the complexity of breastfeeding. They viewed bottle‐feeding as automatic and simple, allowing freedom to leave the infant with others. Although adolescents were adamant that choice of feeding method was their independent decision, social and family influences were evident.

Conclusions.  Consistent with the Theory of Planned Behaviour and other research, attitudes, perceived social influences, and perceived control factors were influential to adolescents when choosing infant feeding methods. The findings suggest that adolescents need education on decision‐making, and are being used to fine‐tune the interventions of a randomized clinical trial to investigate promoting and supporting breastfeeding among adolescent mothers.
The construction and development of health professions: where will it end?
Authors: Colyer Hazel M.
Published: October 2004

Aim.  The aim of this paper is to evaluate the construction and development of professional health work as it has occurred over the past 15 years in the UK and present an informed, speculative analysis of present and future health care work.

Background.  Since the early 1990s, there has been a strong political imperative in the United Kingdom (UK) to develop existing roles in nursing and the allied health professions, blurring professional boundaries and emphasizing patient/client‐centred care delivery. This has already led to major changes in professional work patterns and the privileging of interprofessional work. Many of these changes have been shaped and determined by cultural and economic considerations.

Discussion.  The socio‐political context for the major changes in the roles of non‐medical professionals in the UK is explored to demonstrate both consistency and contradictions with postmodern, consumerist values. The theoretical concepts that underpin professional formation and enable professionalization are examined in relation to present health service drivers for interprofessional work and the development of advanced practice roles, noting similarities and differences in aspirations.

Conclusion.  While professionalization and role development appear to have benefited both professions and service users in the short‐term, their adoption and institutionalization by policymakers are influencing its direction in ways which both may ultimately find troublesome.
Consistent mapping and automatic visual search: comparing persons with and without intellectual disability
Authors: Merrill E. C.
Published: October 2004

Background  Merrill et al. (1996) reported that persons with intellectual disability (ID) were slower at learning a visual search task to automaticity relative to persons of the same age without ID. For persons without ID, automaticity develops most rapidly under conditions in which a response is always the same for a particular stimulus. This study was designed to investigate whether persons with and without ID are differentially sensitive to the influence of consistently mapped versus inconsistently mapped stimulus responses.

Methods  The primary manipulation was the consistency between a particular stimulus and the response to that stimulus in a visual search task. Sixteen participants with ID and 16 without ID searched displays of two, three, or four pictured objects to determine if a target was present. For half of the participants, the targets were always targets. For the other half, the targets became nontargets on 25% of the trials.

Results  Analyses focused on changes in response times associated with set size. Because automaticity allows for parallel processing, the elimination of significant effects of set size was taken as an index of the development of automaticity. Results indicated that inconsistent mapping significantly slowed the development of automaticity for the participants without ID but not for the participants with ID.

Discussion  Results were discussed in terms of the role of inhibition processes in the development of automatic search and detection. The effectiveness of inhibition processes was compromised by the consistency manipulation. The effect of the consistency manipulation was greater for the participants without ID because they were presumed to be using inhibition processes more effectively during practice than did the participants with ID.
Intravenous sedation for dental patients with intellectual disability
Authors: Miyawaki T. , Kohjitani A. , Maeda S. , Egusa M. , Mori T. , Higuchi H. , Kita F. , Shimada M.
Published: October 2004

Background  The poor quality of oral health care for people with intellectual disability (ID) has been recognized, and the strong fears about dental treatment suggested as a major reason for disturbances of visits to dentists by such patients. Intravenous sedation is a useful method for relieving the anxiety and fear of such patients about dental treatment, and is frequently essential for ID patients undergoing dental treatment. However, decision regarding the dose of sedative required to be administered for an adequate level of sedation is difficult because the effect of sedation cannot be adequately assessed in patients with severe ID. As an appropriate sedative dose for dental patients with ID has not been fully established, we investigated sedative doses required and the effect of sedation in patients with ID, compared with other dental patients.

Methods  We reviewed the anaesthetic records of dental patients with ID (73 cases) and other dental patients (19 cases) aged between 20 and 29 years who had undergone intravenous sedation with midazolam and propofol in Okayama University Dental Hospital, from January 2000 to December 2000. Intravenous sedation was induced with a bolus intravenous administration of midazolam (2–3 mg) and maintained with a continuous infusion of propofol. The dose of propofol was titrated to achieve an adequate level of sedation: asleep but responding to painful stimulation. The efficacy of sedation, the required doses of propofol, and the wake‐up times were investigated for all subjects. The efficacy of sedation was evaluated by judging whether the patient became cooperative and allowed the dental treatment to be carried out or not. The complications induced by intravenous sedation were also evaluated in each subject. Differences in variables between subjects with ID and other subjects were analysed using the Mann–Whitney U‐test.

Results  Intravenous sedation was effective for dental treatment in all subjects with or without ID. The required dose of propofol in subjects with ID was 4.74 mg/kg/h (2.63–10.33 mg/kg/h), significantly higher than that required for other subjects (3.31, 1.72–4.80 mg/kg/h). Wake‐up times of subjects with ID were similar to those of the other subjects. Severe complications were not seen during or after intravenous sedation.

Conclusion  The results of this study show that intravenous sedation is a useful method for dental patients with ID as well as for other dental patients, but indicate that dental patients with ID need higher doses of sedative to obtain an adequate level of sedation.
Investigation of the utility of colorectal function tests and Rome II criteria in dyssynergic defecation (Anismus)
Authors: Rao S. S. C. , Mudipalli R. S. , Stessman M. , Zimmerman B.
Published: October 2004

Although 30–50% of constipated patients exhibit dyssynergia, an optimal method of diagnosis is unclear. Recently, consensus criteria have been proposed but their utility is unknown. To examine the diagnostic yield of colorectal tests, reproducibility of manometry and utility of Rome II criteria. A total of 100 patients with difficult defecation were prospectively evaluated with anorectal manometry, balloon expulsion, colonic transit and defecography. Fifty‐three patients had repeat manometry. During attempted defecation, 30 showed normal and 70 one of three abnormal manometric patterns. Forty‐six patients fulfilled Rome criteria and showed paradoxical anal contraction (type I) or impaired anal relaxation (type III) with adequate propulsion. However, 24 (34%) showed impaired propulsion (type II). Forty‐five (64%) had slow transit, 42 (60%) impaired balloon expulsion and 26 (37%) abnormal defecography. Defecography provided no additional discriminant utility. Evidence of dyssynergia was reproducible in 51 of 53 patients. Symptoms alone could not differentiate dyssynergic subtypes or patients. Dyssynergic patients exhibited three patterns that were reproducible: paradoxical contraction, impaired propulsion and impaired relaxation. Although useful, Rome II criteria may be insufficient to identify or subclassify dyssynergic defecation. Symptoms together with abnormal manometry, abnormal balloon expulsion or colonic marker retention are necessary to optimally identify patients with difficult defecation.
Genetic engineering of glycinebetaine synthesis in tomato protects seeds, plants, and flowers from chilling damage
Authors: Park Eung‐Jun , Jeknić Zoran , Sakamoto Atsushi , DeNoma Jeanine , Yuwansiri Raweewan , Murata Norio , Chen Tony H. H.
Published: October 2004

Tomato (Lycopersicon esculentumMill.) plants, which normally do not accumulate glycinebetaine (GB), are susceptible to chilling stress. Exposure to temperatures below 10°C causes various injuries and greatly decreases fruit set in most cultivars. We have transformed tomato (cv. Moneymaker) with a chloroplast‐targetedcodAgene ofArthrobacter globiformis, which encodes choline oxidase to catalyze the conversion of choline to GB. These transgenic plants expresscodA and synthesize choline oxidase, while accumulating GB in their leaves and reproductive organs up to 0.3 and 1.2 μmol g−1fresh weight (FW), respectively. Their chloroplasts contain up to 86% of total leaf GB. Over various developmental phases, from seed germination to fruit production, these GB‐accumulating plants are more tolerant of chilling stress than their wild‐type counterparts. During reproduction, they yield, on average, 10–30% more fruit following chilling stress. Endogenous GB contents as low as 0.1 μmol g−1FW are apparently sufficient to confer high levels of tolerance in tomato plants, as achieved via transformation with thecodAgene. Exogenous application of either GB or H2O2improves both chilling and oxidative tolerance concomitant with enhanced catalase activity. These moderately increased levels of H2O2incodAtransgenic plants, as a byproduct of choline oxidase‐catalyzed GB synthesis, might activate the H2O2‐inducible protective mechanism, resulting in improved chilling and oxidative tolerances in GB‐accumulatingcodAtransgenic plants. Thus, introducing the biosynthetic pathway of GB into tomato through metabolic engineering is an effective strategy for improving chilling tolerance.