bluuebunny/crossref_metadata_2025 huggingface dataset:
Ipaf is upregulated by tumor necrosis factor‐α in human leukemia cells
Authors: Gutierrez Olga , Pipaon Carlos , Fernandez-Luna Jose L.
Published: May 2004

Ipaf has been associated with apoptosis, cytokine processing, and nuclear factor‐κB activation. Here, we describe that Ipaf is highly expressed in myelomonocytic cells and that the mRNA levels of Ipaf progressively increase during differentiation of CD34+ progenitors to granulocytes and monocytes. Additionally, treatment with tumor necrosis factor‐α and exposure to UV radiation induced the transcriptional activation of Ipaf in human leukemia HL‐60 cells. Thus, Ipaf may contribute to modulate the response of myeloid cells to genotoxic and pro‐inflammatory stimuli.
Insights into the specificity of RNA cleavage by the Escherichia coli MazF toxin
Authors: Muñoz-Gómez Ana J. , Santos-Sierra Sandra , Berzal-Herranz Alfredo , Lemonnier Marc , Dı́az-Orejas Ramón
Published: May 2004

The mazEF (chpA) toxin–antitoxin system of Escherichia coli is involved in the cell response to nutritional and antibiotic stresses as well as in bacterial‐programmed cell death. Valuable information on the MazF toxin was derived from the determination of the crystal structure of the MazE/MazF complex and from in vivo data, suggesting that MazF promoted ribosome‐dependent cleavage of messenger RNA. However, it was concluded from recent in vitro analyses using a MazF‐(His6) fusion protein that MazF was an endoribonuclease that cleaved messenger RNA specifically at 5′‐ACA‐3′ sites situated in single‐stranded regions. In contrast, our work reported here shows that native MazF protein cleaves RNA at the 5′ side of residue A in 5′‐NAC‐3′ sequences (where N is preferentially U or A). MazF‐dependent cleavage occurred at target sequences situated either in single‐ or double‐stranded RNA regions. These activities were neutralized by a His6‐MazE antitoxin. Although essentially consistent with previous in vivo reports on the substrate specificity of MazF, our results strongly suggest that the endoribonuclease activity of MazF may be modulated by additional factors to cleave messenger and other cellular RNAs.
Some amphiphilic cations block the mitochondrial apoptosis‐induced channel, MAC
Authors: Martinez-Caballero Sonia , Dejean Laurent M , Kinnally Kathleen W
Published: May 2004

The mitochondrial apoptosis‐induced channel (MAC) forms in the outer membrane of mitochondria early in apoptosis and this activity is altered by physiological levels of cytochrome c. While cyclosporine A and lidocaine have no effect, dibucaine induces a fast blockade of MAC with an IC50 of 39 μM. In contrast, the IC50 for propranolol and trifluoperazine are 52 and 0.9 μM, respectively, and these drugs likely destabilize the open state of MAC. These agents, and others not yet identified, should be valuable tools in the study of apoptosis. Profiling MAC's pharmacology may generate novel therapeutic regimes for disease.
Insertional‐fusion of basic fibroblast growth factor endowed ribonuclease 1 with enhanced cytotoxicity by steric blockade of inhibitor interaction
Authors: Tada Hiroko , Onizuka Masayuki , Muraki Kazuko , Masuzawa Wataru , Futami Junichiro , Kosaka Megumi , Seno Masaharu , Yamada Hidenori
Published: May 2004

Basic fibroblast growth factor (bFGF) was inserted in the middle of human ribonuclease 1 (RNase1) sequence at an RNase inhibitor (RI)‐binding site (Gly89) by a new gene fusion technique, insertional‐fusion. The resultant insertional‐fusion protein (CL‐RFN89) was active both as bFGF and as RNase. Furthermore, it acquired an additional ability of evading RI through steric blockade of RI‐binding caused by fused bFGF domain. As a result, CL‐RFN89 showed stronger growth inhibition on B16/BL6 melanoma cells than an RI‐sensitive tandem fusion protein. Thus, the insertional‐fusion technique increases accessible positions for gene fusion on RNase, resulting in construction of a potent cytotoxic RNase.
Links between fatty acids and expression of UCP2 and UCP3 mRNAs
Authors: Thompson Mary P , Kim Dongho
Published: May 2004

Physiological and pathological states that are associated with elevated plasma fatty acids (FAs) increase uncoupling protein 2 (UCP2) mRNA in white adipose tissue and UCP3 mRNA in skeletal muscle and heart. A direct effect of unsaturated fatty acids from all classes has been shown in various cultured cells. There is evidence that FAs could induce expression of UCPs by acting as ligands for peroxisome proliferator‐activated receptors, influencing the function of sterol responsive element binding protein or activating 5′‐AMP‐activated protein kinase. Oleic acid has been shown to stimulate the activity of the promoter regions of UCP2 and UCP3 genes and the FA responsive regions are beginning to be characterised.
Binding of phage‐display‐selected peptides to the periplasmic chaperone protein SurA mimics binding of unfolded outer membrane proteins
Authors: Bitto Eduard , McKay David B
Published: May 2004

SurA is a periplasmic chaperone protein that facilitates maturation of integral outer membrane proteins (OMPs). Short peptides that bind SurA have previously been characterized. In this work, an enzyme‐linked immunoabsorbent assay‐based competition assay is utilized to demonstrate that binding of such peptides, presented by peptide‐tagged phage, mimics binding of biological substrates. Two representative unfolded OMPs, OmpF and OmpG, bind SurA and a core structural fragment thereof in competition with peptide‐tagged phage, and with the same order‐of‐magnitude affinity as the peptides. Additionally, unfolded OmpF and OmpG bind SurA more tightly than an unfolded water‐soluble protein, while folded proteins have no measurable affinity, demonstrating a specificity of SurA for OMP polypeptides.
Twelve receptor molecules attach per viral particle of human rhinovirus serotype 2 via multiple modules
Authors: Konecsni Tünde , Kremser Leopold , Snyers Luc , Rankl Christian , Kilár Ferenc , Kenndler Ernst , Blaas Dieter
Published: May 2004

The crystallographic T=1 (pseudo T=3) icosahedral symmetry of the human rhinovirus capsid dictates the presence of 60 identical, symmetry related surface structures that are available for antibody and receptor binding. X‐ray crystallography has shown that 60 individual very‐low density lipoprotein receptor (VLDLR) modules bind to HRV2. Their arrangement around the fivefold axes of the virion suggested that tandem oligomers of such modules could attach simultaneously to symmetry‐related sites. By resolving virus particles carrying various numbers of artificial recombinant concatemers of VLDLR repeat 3 (V33333) by capillary electrophoresis and extrapolation of the measured mobilities to that at saturation of all binding sites, we present evidence for up to 12 molecules of the concatemer to bind one single virion.
Seven copepod species considered as indicators of water-mass influence and changes: results from a Northumberland coastal station
Authors: Bonnet D , Frid C
Published: May 2004

Zooplankton has been sampled monthly since 1969 at Station Z off the Northumberland coast. Seven copepod species were chosen as potential indicators of specific water masses. Data have been analysed to provide information about seasonal and interannual changes in the zooplankton community with special reference to the indicator taxa and to the possible role of hydrographic and climate drivers, including variations in the position of the Gulf Stream North Wall position and the North Atlantic Oscillation. Results show that, at this Northumberland coastal station, some copepod species are likely to be good indicators of water-mass influence and changes.
Sagitta friderici Ritter-Záhony (Chaetognatha) from South Atlantic waters: abundance, population structure, and life cycle
Authors: Daponte M.C , Capitanio F.L , Nahabedian D.E , Viñas M.D , Negri R.M
Published: May 2004

The life cycle of Sagitta friderici, a neritic species from Pacific, Atlantic, and Mediterranean waters, has been poorly studied. Aiming at increasing our knowledge of this species in the Argentine Sea, the size structure, dry weight, distribution of maturity stages (ovarian, testicular, and seminal vesicles development), and life-cycle duration were studied from samples obtained at a permanent station (EPEA STATION, 38°28′S 57°41′W) from 9 March 2000 to 10 April 2001. The almost permanent presence of juveniles and the extended period during which mature adults (stage III) were detected suggest that reproduction occurs continuously with two main peaks, the main one in the summer (December–February) and a lesser one in the fall (April–May). Significant (p<0.05) inverse correlations between water temperature and the mean size of stages 0 (juveniles), I, and II were found in this data set. Owing to the influence of temperature, those individuals that develop during the warm season and mature in the fall attain smaller sizes (7.6–12.4 mm) than those that develop during the coldest period of the year and mature in the spring (10.0–15.2 mm). The life-cycle duration is approximately 15 months, and the growth rate ca. 0.03 mm d−1. The weight increase as a function of individual size was similar in the fall and in the spring (Fisher Test, p>0.05).
Population structure of the copepods Centropages typicus and Temora stylifera in different environmental conditions
Authors: Di Capua Iole , Mazzocchi Maria Grazia
Published: May 2004

The population structure (NI to adults) of the copepods Centropages typicus and Temora stylifera was investigated in parallel at two sites in the eutrophic and oligotrophic waters of the Gulf of Naples (Tyrrhenian Sea) with the aim of identifying the environmental factors that modulate the occurrence of these calanoids that are abundant in the neritic waters of the Mediterranean Sea. Monthly zooplankton sampling was conducted from May 1999 to June 2000 in 5–7 discrete depth layers in the upper 200 m with a 70-μm mesh net. Temperature, salinity, and fluorescence profiles were recorded by CTD casts. The remarkable differences observed in the temporal and spatial patterns of the two populations throughout their developmental cycles seem to result more from different responses to environmental factors than from different life-history traits. C. typicus was abundant in early to mid-summer and was distributed in the whole water column; T. stylifera followed in late summer–autumn and occurred preferentially in the upper 30 m. Temperature was the main regulating factor for T. stylifera. The availability of autotrophic food appeared relatively more important for C. typicus, although unequivocal signals were not observed, suggesting that more complex trophic interactions likely affect the dynamics of the two populations.
Life cycle strategies of Northern krill (Meganyctiphanes norvegica) for regulating growth, moult, and reproductive activity in various environments: the case of fjordic populations
Authors: Cuzin-Roudy J , Tarling G.A , Strömberg J.-O
Published: May 2004

Adaptive strategies of two fjord populations of Northern krill (Meganyctiphanes norvegica Sars) were studied and compared with other populations from different climatic and oceanic conditions. The Gullmarsfjord (West Sweden) and the Clyde Sea (West Scotland) resident populations followed the same basic pattern of development as the Kattegat (between Denmark and Sweden) and the Ligurian Sea (Northwest Mediterranean) populations, but the fjord krill reached a comparatively larger body size during their second year of life. The positive relationship between body size and fecundity means that fjord populations are potentially more productive than those of the open sea. High rates of moulting and spawning activity were limited to the spring and summer despite the fact that trophic conditions still seemed favourable in early autumn. We show here that, in autumn, the adult moult cycle became longer and growth stopped, large 2-year-old krill disappeared from the population and ovarian development was arrested. Resources already accumulated in the oocytes (glycoproteic and lipid yolk) were recovered by oosorption and ovaries regressed for a winter rest. Autumn trophic conditions were still favourable in both sites, especially in terms of copepod abundance. However, the phytoplankton community changed from a dominance of diatoms in early season to dinoflagellates in late summer. We suggest that these changes triggered the autumn arrest of krill production.
Radiotracer determination of the diet of calanoid copepod nauplii and copepodites in a temperate estuary
Authors: Finlay Kerri , Roff John C
Published: May 2004

Many studies have focused on the consumption of specific prey items and clearance rates on natural food particles by copepod adults and copepodites, but few have addressed the feeding habits of the youngest stages, the nauplii. Because of the difference in size and shape between copepod developmental stages, corresponding differences in diet would be expected. This subject was addressed using a modification of a new method offering radiolabelled natural food particles (with 3H for heterotrophs and 14C for autotrophs) to nauplii and copepodites of the copepods in a temperate estuary. By measuring the uptake of the radiolabel by the copepods it was possible to determine clearance rates on different sizes and types of food particles. All copepods began feeding on food sources >2 μm in size, and feeding on heterotrophs by all species and stages was considerably lower than feeding on autotrophs. Overall, it appears that copepod nauplii have a comparable diet to the later stages in terms of food type and size and therefore it is unlikely that nauplii are a more efficient link between the microbial foodweb and the classical foodweb, at least in temperate estuarine waters.
Microzooplankton production in the oceans
Authors: Landry Michael R. , Calbet Albert
Published: May 2004

A literature synthesis of phytoplankton growth (μ) and grazing (m) rate estimates from dilution experiments reveals that microzooplankton account for most phytoplankton mortality in the oceans, averaging 60–75% of daily phytoplankton production (PP) across a spectrum of open-ocean and coastal systems. For reasonable estimates of gross growth efficiency (GGE=30–40%), such impacts imply that secondary production rates of microzooplankton (MP2°) are typically in the range 21–34% of PP. However, multiple trophic transfers within the microbial community can further enhance total microzooplankton production by an additional third to a half (MPtot=28–55% of PP). These estimates are 2–5 times typical values for bacterial production (10–15% of PP). Thus, in aggregate and on average, microzooplankton consume substantially more (6–7 times) production from phytoplankton than from heterotrophic bacteria. High grazing impacts and relatively high GGEs are consistent with population growth rates for microzooplankton and phytoplankton that are roughly equivalent under ambient conditions, which may be requisite for grazing regulation. Transfer efficiencies of microzooplankton production to mesozooplankton depend critically on the number of predatory interactions among micro-consumers, and may be one way in which systems differ substantially. Overall, the ability to quantify microzooplankton production in terms of more broadly measured rates of PP provides a potential avenue for broadening our understanding of ocean community dynamics through remote sensing and modelling.
Enumeration, measurement, and identification of net zooplankton samples using the ZOOSCAN digital imaging system
Authors: Grosjean Philippe , Picheral Marc , Warembourg Caroline , Gorsky Gabriel
Published: May 2004

Identifying and counting zooplankton are labour-intensive and time-consuming processes that are still performed manually. However, a new system, known as ZOOSCAN, has been designed for counting zooplankton net samples. We describe image-processing and the results of (semi)-automatic identification of taxa with various machine-learning methods. Each scan contains between 1500 and 2000 individuals <0.5 mm. We used two training sets of about 1000 objects each divided into 8 (simplified) and 29 groups (detailed), respectively. The new discriminant vector forest algorithm, which is one of the most efficient methods, discriminates between the organisms in the detailed training set with an accuracy of 75% at a speed of 2000 items per second. A supplementary algorithm tags objects that the method classified with low accuracy (suspect items), such that they could be checked by taxonomists. This complementary and interactive semi-automatic process combines both computer speed and the ability to detect variations in proportions and grey levels with the human skills to discriminate animals on the basis of small details, such as presence/absence or number of appendages. After this checking process, total accuracy increases to between 80% and 85%. We discuss the potential of the system as a standard for identification, enumeration, and size frequency distribution of net-collected zooplankton.
Comparative ecology of over-wintering Calanus finmarchicus in the northern North Atlantic, and implications for life-cycle patterns
Authors: Heath Michael R , Boyle Peter R , Gislason Astthor , Gurney William S.C , Hay Stephen J , Head Erica J.H , Holmes Steven , Ingvarsdóttir Anna , Jónasdóttir Sigrun H , Lindeque Pennie , Pollard Raymond T , Rasmussen Jens , Richards Kelvin , Richardson Katherine , Smerdon Gary , Speirs Douglas
Published: May 2004

Data from plankton net and Optical Plankton Counter sampling during 12 winter cruises between 1994 and 2002 have been used to derive a multi-annual composite 3-D distribution of the abundance of over-wintering Calanus finmarchicus in a swath across the North Atlantic from Labrador to Norway. Dense concentrations occurred in the Labrador Sea, northern Irminger Basin, northern Iceland Basin, eastern Norwegian Sea, Faroe–Shetland Channel, and in the Norwegian Trench of the North Sea. A model of buoyancy regulation in C. finmarchicus was used to derive the lipid content implied by the in situ temperature and salinity at over-wintering depths, assuming neutral buoyancy. The Faroe–Shetland Channel and eastern Norwegian Sea emerged as having the highest water column-integrated abundances of copepodites, the lowest over-wintering temperature, and the highest implied lipid content. The results are discussed in the context of spatial persistence of populations, seasonal patterns of abundance, and relationships between over-wintering and lipid accumulation in the surface waters.
Mesozooplankton size-fractionated metabolism and feeding off NW Spain during autumn: effects of a poleward current
Authors: Isla José Alejandro , Anadón Ricardo
Published: May 2004

Two consecutive cruises were carried out off NW Spain in October 1999 in an attempt to obtain information on the poleward current that affects the hydrodynamics of this area during autumn and winter. The stations sampled were divided into three zones: coastal (C), between the saline intrusion and the coast; poleward current (P), where salinity at 100-m depth was >35.85; and oceanic (O), outside the poleward current. Phytoplankton biomass, integrated through the photic zone, was similar for the three zones. Conversely, mesozooplankton biomass showed high spatial variation, with the lowest values associated with the high-salinity current. There was a decreasing trend in the relative importance of the biomass of the largest size class (>1000 μm) from coastal to oceanic zones. The lowest percentages of both Chl a and primary production ingested daily by copepods were measured at the poleward current stations. Specific metabolic rates were not significantly different between zones. The total amount of carbon respired and the NH4 and PO4 released were highest in coastal areas and lowest within the poleward current, in agreement with the pattern observed for mesozooplankton biomass. Diel vertical migrations were more marked in the coastal areas, decreasing gradually towards the oceanic stations. The role of mesozooplankton in promoting the flux of carbon, nitrogen, and phosphorus followed the same spatial distribution. Overall, the contribution of mesozooplankton to biogeochemical cycles seems to be minor in the poleward current compared to the other two zones, possibly as a consequence of the low biomass associated with this current.
Composition and temporal distribution of cirripede larvae in Southampton Water, England, with particular reference to the secondary production of Elminius modestus
Authors: Muxagata Erik , Williams John A , Sheader Martin
Published: May 2004

Southampton Water, an estuary on the south coast of England, has been the focus of a number of studies to determine the seasonality and productivity of its pelagic community. Although recognized as important in previous studies, the meroplankton component and, in particular, the cirripedes have been largely ignored, though they rank second to the Copepoda in abundance. In order to estimate the contribution of barnacle larvae to the pelagic community, 42 quantitative zooplankton samples were collected from a fixed station within the estuary during a period of 19 months (from 12 January 2001 until 16 July 2002). As expected, barnacles were the second most abundant group averaging 13% of the total population, and accounting for up to 60% on some occasions. Eight barnacle species were identified: Elminius modestus, Balanus improvisus, Balanus crenatus, Semibalanus balanoides, Verruca stroemia, Chthamalus stellatus, Sacculina carcini, and Peltogaster paguri. Of these E. modestus was the most abundant and frequent, dominating the Cirripedia fraction throughout the year, but being outnumbered by B. crenatus from February to May. Secondary production was calculated for E. modestus and mean daily rates of 0.077 mg C m−3 d−1 (28.08 mg C m−3 yr−1) were found.
A comparative study of Calanus finmarchicus mortality patterns at five localities in the North Atlantic
Authors: Ohman M.D , Eiane K , Durbin E.G , Runge J.A , Hirche H.-J
Published: May 2004

We compare the patterns of stage-specific mortality of Calanus finmarchicus at five localities across the North Atlantic Ocean during the spring–summer period of active population growth: Georges Bank, a continental shelf locality in the NW Atlantic, based on 30 broadscale survey cruises in the US GLOBEC program; the northern North Sea, studied during the historic FLEX program with sampling four times daily for 73 days; Ocean Station M in the central Norwegian Sea, based on an 80-day daily time-series; and Lurefjorden (sampled weekly in late winter–early summer) and Sørfjorden (sampled monthly), two fjords in southwestern Norway characterized by markedly different guilds of predators. The mortality estimation methods included Wood's Population Surface Method, the Vertical Life Table (VLT) method, and a modified VLT, according to the study site and copepod recruitment schedules. Contrary to assumptions implicit in many simulation models and indirect methods for estimating zooplankton mortality, both rates and stage-specific patterns of mortality of C. finmarchicus vary appreciably across the North Atlantic. Characteristics of local environments, including the predator field in particular, appear to strongly influence mortality schedules in different regions. In at least two sites (Georges Bank and Ocean Station M), mortality rates of early stages of C. finmarchicus are density-dependent. We attribute this density-dependent mortality to egg cannibalism, which introduces non-linear population responses to changing environmental conditions. Region-specific biological interactions can substantially modify the effects of physical climate variability and render simple linear relationships between climate and zooplankton abundance unlikely.
Interannual abundance patterns of copepods during an ENSO event in Icy Strait, southeastern Alaska
Authors: Park Wongyu , Sturdevant Molly , Orsi Joseph , Wertheimer Alex , Fergusson Emily , Heard William , Shirley Thomas
Published: May 2004

Interannual copepod abundance (number m−3) and sea surface temperatures (SST, 2-m depth) were examined from four stations in Icy Strait, southeastern Alaska, monthly from May to September, 1997–2002. SST was generally lowest in May (≅7°C), increased rapidly to a summer peak (≅12°C), and declined again by September. SST was relatively high in the El Niño year, 1998, and was low during a regional cold event, 2002, compared to other years. Overall, copepods constituted 18.8% of the total biomass and 88.2% of zooplankton abundance, and included >34 species. The common copepod species were grouped into two size classes by total length (TL), those >2.5 mm (11.4% biomass, 24.2% abundance) and those <2.5 mm (7.4% biomass, 64.0% abundance). In order of dominance, large species included Metridia ochotensis, Calanus marshallae, M. pacificus, and Neocalanus spp. and small species included Pseudocalanus spp., Acartia longiremis, and Centropages abdominalis. Overall, the small species were more abundant than the large species. Densities of large copepods were relatively low compared to those of small copepods during El Niño (1998) and a cold year (2002), suggesting that large copepods with long lifespans are more sensitive to ocean climate fluctuation.
Vertical and seasonal distribution of eight Clausocalanus species (Copepoda: Calanoida) in oligotrophic waters
Authors: Peralba Àurea , Mazzocchi Maria Grazia
Published: May 2004

Copepods of the genus Clausocalanus Giesbrecht, 1888 are among the most abundant calanoids in the Mediterranean Sea, both in coastal and offshore regions. The vertical distribution of C. arcuicornis, C. furcatus, C. jobei, C. lividus, C. mastigophorus, C. parapergens, C. paululus, and C. pergens, which co-occur in the upper 200 m in the Gulf of Naples (Tyrrhenian Sea), was investigated during an annual sampling cycle conducted at an offshore station in 2002. The quantitative data on distribution of each species were analysed in relation to the environmental parameters. The patterns that we observed in the seasonal cycles and vertical distribution provided insights on the ecological niches of the eight Clausocalanus species.
Identifying global synchronies in marine zooplankton populations: issues and opportunities
Authors: Perry R.Ian , Batchelder Harold P , Mackas David L , Chiba Sanae , Durbin Edward , Greve Wulf , Verheye Hans M
Published: May 2004

Analyses of the influences of climate variability on local zooplankton populations and those within ocean basins are relatively recent (past 5–10 years). What is lacking are comparisons of zooplankton population variability among the world's oceans, in contrast to such global comparisons of fish populations. This article examines the key questions, capabilities, and impediments for global comparisons of zooplankton populations using long-term (>10 year) data sets. The key question is whether global synchronies in zooplankton populations exist. If yes, then (i) to what extent are they driven by “bottom-up” (productivity) or “top-down” (predation) forcing; (ii) are they initiated by persistent forcing or by episodic events whose effects propagate through the system with different time-lags; and (iii) what proportion of the biological variance is caused directly by physical forcing and what proportion might be caused by non-linear instabilities in the biological dynamics (e.g. through trophodynamic links)? The capabilities are improving quickly that will enable global comparisons of zooplankton populations. Several long-term sampling programmes and data sets exist in many ocean basins, and the data are becoming more available. In addition, there has been a major philosophical change recently that now recognizes the value of continuing long-term zooplankton observation programmes. Understanding of life-history characteristics and the ecosystem roles of zooplankton are also improving. A first and critical step in exploring possible synchrony among zooplankton from geographically diverse regions is to recognize the limitations of the various data sets. There exist several impediments that must be surmounted before global comparisons of zooplankton populations can be realized. Methodological issues concerned with the diverse spatial and temporal scales of “monitored” planktonic populations are one example. Other problems include data access issues, structural constraints regarding funding of international comparisons, and lack of understanding by decision-makers of the value of zooplankton as indicators of ecosystem change. We provide recommendations for alleviating some of these impediments, and suggest a need for an easily understood example of global synchrony in zooplankton populations and the relation of those signals to large-scale climate drivers.
A 9-year increasing trend in mesozooplankton biomass at the Hawaii Ocean Time-series Station ALOHA
Authors: Sheridan Cecelia C , Landry Michael R
Published: May 2004

Mesozooplankton biomass in the North Pacific Subtropical Gyre (NPSG), as measured by the Hawaii Ocean Time-series program at Station ALOHA (22.45°N 158°W), increased significantly from 1994 to 2002. The changes occurred at a rate of 60 mg DW m−2 yr−1 for night-time collections and 45 mg DW m−2 yr−1 for daytime collections. Principal components analysis indicates that the 9-year trend was driven by an increase in small (0.5–2.0 mm) zooplankton that do not migrate on a diel cycle. This plankton class is known to increase during the summer at Station ALOHA when the water column is most stratified, and a strong summertime response is also apparent within the long-term trend from 1998 through 2002. Both long-term and seasonal changes in zooplankton biomass at Station ALOHA can be linked to an enhanced role of nitrogen fixation in ecosystem productivity. Climate forcing from El Niño–Southern Oscillation (ENSO) events may have influenced nitrogen fixation, general ecosystem productivity, and thus zooplankton biomass in the NPSG. However, it is difficult to evaluate the effect of climate cycles in this region without the benefit of a longer time-series at Station ALOHA. Because biomass trends in higher-level consumers like mesozooplankton can have cascading influences on lower levels, understanding the relative roles of bottom-up climate influences and top-down trophic processes will be important in resolving long-term trends in community composition and structure in the subtropical North Pacific Ocean.
Effects of food concentration and diet on chromophoric dissolved organic matter accumulation and fluorescent composition during grazing experiments with the copepod Calanus finmarchicus
Authors: Urban-Rich Juanita , McCarty James T , Shailer Mark
Published: May 2004

Laboratory experiments were conducted with Calanus finmarchicus copepodites IV–V to examine the effects of food concentration, food type, and life stage on chromophoric dissolved organic matter (CDOM) release from copepods. Changes in CDOM absorption and fluorescence were monitored by incubating copepods in rotating bottles for 24 h in the dark with controlled diets. Copepods were fed a range of food concentrations from 800 to 15 000 cells l−1 of either Thalassiosira weissflogii and Skeletonema costatum or Prorocentrum minimum in stationary and exponential growth phases. Results from these studies indicate that diet does have an effect on the amount and type of CDOM released by C. finmarchicus. A diet of either diatoms or dinoflagellates in exponential growth will result in a release of humic-like material, while feeding on senescent cells leads to a net input of protein-like material. Only at very high senescent cell concentrations (>5000 cells l−1) can humic-like material accumulate. This could lead to seasonal cycles in the amount and type of CDOM released by copepods, such that humic-like material will be released in the spring and at the height of phytoplankton blooms, while protein-like material will be added to the water as the bloom dies. The humic-like material found in these studies is blue-shifted compared to the standard humic material (Peaks A, M, and C) measured in seawater. The role of this humic-like material in the environment is currently unknown, but it could be important in absorbing UV radiation.
Spatial patterns of mesozooplankton distribution in the Southwestern Atlantic Ocean (34°–41°S) during austral spring: relationship with the hydrographic conditions
Authors: Marrari Marina , Viñas María Delia , Martos Patricia , Hernández Daniel
Published: May 2004

The mesozooplankton community was analysed in a large region of the Argentine Shelf (34°–41°S) on the main spring spawning ground of the anchovy (Engraulis anchoita), and its spatial pattern was related to the hydrographic conditions. Copepods smaller than 1 mm dominated the community. Three faunistic areas were identified by cluster analysis: northern coastal area (NCA), southern coastal area (SCA), and shelf area (SA), each with distinct physical conditions. The NCA, influenced by the Río de la Plata estuary, had relatively high temperature, the lowest salinity, and the highest stratification values. The SCA had the highest salinity and a vertically homogeneous water column. The SA, vertically stratified, was influenced by the Río de la Plata estuary and by Subantarctic shelf waters and had the lowest temperature values and the greatest depths. Canonical correlation analysis was used to analyse the relationship between zooplankton and physical variables and four zooplankton assemblages were identified. Group A included the copepods Calanus australis, C. simillimus, Clausocalanus brevipes, Centropages brachiatus, Drepanopus forcipatus, Oithona atlantica, and O. helgolandica, and was preferentially distributed in the SA. Group B, composed of the copepods Acartia tonsa and Corycaeus spp. and the cladoceran Pleopis polyphemoides, showed a strong preference for the NCA. Group C included Labidocera fluviatilis, Ctenocalanus vanus, Paracalanus spp., Calanoides cf. carinatus, Euterpina acutifrons, Oithona nana, and the cladoceran Evadne nordmanni, and was preferentially distributed in coastal areas (NCA and SCA). Group D only included the cladoceran Podon intermedius and was mainly located in high salinity waters of the SCA. Small, omnivorous, fast-reproducing species (groups B, D, and most of C) are better adapted to warmer variable and less productive coastal areas, whereas larger herbivorous species (most of group A) seem to better exploit colder stratified and more productive shelf waters. The mesozooplankton community provides adequate food for E. anchoita larvae in coastal areas and for adults in shelf waters.
Zooplankton variability and climatic anomalies from 1994 to 2001 in the Balearic Sea (Western Mediterranean)
Authors: Fernández de Puelles M. Luz , Valencia Joaquín , Vicente Laura
Published: May 2004

The long-term and seasonal changes in biomass and zooplankton abundance at a station off Mallorca Island (Balearic Sea) were studied in relation to the main physical and chemical conditions. The results are based on a total of 276 samples collected every 10 days during 8 years by means of oblique hauls from bottom to surface. At this neritic station (77-m depth) located in a hydrographic area between northern Mediterranean and Atlantic southern waters, salinity ranged from 37 to 38.4 psu and temperature from 13.4°C (February 1996) to 27.4°C (August 1998). With the exception of salinity, the other environmental parameters and the most abundant zooplankton groups showed irregular but seasonal cycles. Interannual variability was also observed, with higher zooplankton abundance during the cooler and more saline years when the influence of northern water was stronger. Zooplankton abundance decreased during a warm period in 1998. Copepods were the most abundant group (54%) and their abundance was significantly correlated with temperature (negatively) and salinity (positively). Here, we summarize the changes in the zooplankton community abundance and how hydrographic forcing and other climatic factors have changed during the period from 1994 to 2001 in the Balearic Sea (Western Mediterranean).
Lagrangian modelling studies of Antarctic krill (Euphausia superba) swarm formation
Authors: Hofmann Eileen E , Haskell A.G.Edward , Klinck John M , Lascara Cathy M
Published: May 2004

A two-dimensional Lagrangian particle model was developed to examine the spatial distribution of Antarctic krill (Euphausia superba). The time-dependent location of particles, which represent krill individuals, is determined by random diffusion, foraging activity, and movement induced by the presence of neighbours. Foraging activity is based on prescribed food conditions and is such that krill swim slower and turn more frequently in areas of high food concentration. The presence or absence of neighbours either disperses krill, if the local concentrations become too dense, or coalesces krill, if concentrations become too dilute, respectively. Predation on krill is included and affects swarm characteristics by removing individuals. Sensitivity studies indicate that the rate of krill swarm formation and the total number of swarms formed are determined primarily by foraging response and nearest neighbour sensing distance. Simulations using food distributions that are representative of those encountered at boundaries, such as fronts, mesoscale eddies, or the sea ice edge, show that foraging activity can produce rapid swarm formation. Results from other krill swarm models show that attraction between individuals is the primary mechanism producing krill swarms. However, the parameterizations for krill interactions used in those models and that used in this model differ, thereby implying different biological dynamics. Thus, parameterization of the basic interactions in krill swarm models remains to be defined.
Achieving appropriate design and widespread use of health care technologies in the developing world
Authors: Free Michael J.
Published: May 2004

Objectives: To identify and describe constraints facing the development and dissemination of technologies appropriate for public health care challenges and solutions in the developing world. Methods: Review of lessons learned in development and introduction of numerous health technologies as experienced by a non‐profit organization working on technologies for 25 years. Results: Many obstacles prevent appropriate technologies from reaching widespread use and acceptance. These include low profit margins in developing world markets, regulatory constraints, and the need for systems changes. Strong public/private‐sector partnerships and realistic approaches to working in these environments make a difference. Conclusions: There is a growing awareness of the need for new technologies and experience with strategies that can make them happen. Some technologies with documented value for maternal care in developing world settings appear to be stuck short of widespread acceptance and use. Understanding the factors impeding their progress can enable the public sector and its collaborators to organize and facilitate their progress more effectively.
Puerperal sepsis and maternal mortality: what role can new technologies play?
Authors: Hussein J. , Fortney J.A.
Published: May 2004

Objective: To identify new and underutilized technologies to reduce maternal mortality related to puerperal sepsis in developing countries. Method: Review of current medical literature. Result: The literature indicates that infection‐control protocols and evidence‐based procedures—including prophylactic antibiotics for cesarean section or preterm rupture of membranes, and updated antibiotic regimens—should be widely adopted. Devices such as hand rubs, needle‐disposal systems, and rapid microbiological diagnostic tests can improve compliance and efficiency. Operational research on promising developments like vaginal cleansing with antiseptics, vitamin A supplementation, and prophylactic antibiotics in high‐risk women is needed. Conclusion: Sepsis management continues to depend on good implementation of established technologies. Program‐based approaches are required to improve uptake.
Obstructed labor: using better technologies to reduce mortality
Authors: Hofmeyr G.J
Published: May 2004

Objective: To identify, from the best available evidence, underutilized and promising technologies that may reduce maternal mortality from obstructed labor. Methods: The author sought systematic reviews of randomized trials, individual randomized trials, and, in the absence of randomized data, non‐randomized studies and clinical consensus. Data were presented according to the level of the evidence. Results: Obstructed labor causes approximately 8% of maternal deaths, and indirectly contributes to a greater percentage. Proven or widely accepted technologies that help reduce mortality from obstructed labor include contraception, external cephalic version, the partogram, augmentation of labor, selective amniotomy, selective episiotomy, vacuum extraction, caesarean section, symphysiotomy, and destructive procedures for non‐viable fetuses. Technologies of uncertain usefulness include maternal height and shoe size, vaginal cleansing, upright posture for delivery and vaginal lubrication. Unuseful technologies include pelvimetry, estimating fetal weight, early labor induction, routine amniotomy and augmentation, routine episiotomy, and starvation during labor. Conclusion: Access to well‐established technologies, particularly safe caesarean section, can reduce maternal mortality in resource‐poor countries.
Auxiliary technologies related to transport and communication for obstetric emergencies
Authors: Krasovec K.
Published: May 2004

Objectives: To review the evidence on appropriate transport and communications technologies for obstetrical referrals in developing countries. Methods: Review of articles published in peer‐reviewed journals and gray literature, supplemented by email and telephone consultations with key informants and field programmers. Results: A wide range of transportation options have been attempted. Initial approaches—such as those relying on ambulances owned and operated by health systems—have evolved into recommendations that emphasize community‐based solutions. There are fewer options within the realm of communications technologies, and the recommendations are more consistent. Public health researchers are only beginning to evaluate the cost and effectiveness of different options. Conclusions: One of the greatest barriers to effective use of transport and communications for obstetric emergencies is the short time interval necessary for action, which limits options for obstetric referrals more than for other medical referrals. Although evidence is still scarce, experience suggests that motorized transport is likely to be the most acceptable and effective transportation option. More sophisticated communications technologies such as cell phones are both practical and effective, and are increasingly becoming the technologies of choice for low‐resource settings.
Vitamin A deficiency as a preventable cause of maternal mortality in undernourished societies: plausibility and next steps
Authors: West Jr K.P.
Published: May 2004

Maternal vitamin A deficiency is a public health problem in the developing world. Recent evidence from Nepal suggests that supplementing populations of rural, poor, and undernourished women with a recommended dietary amount of vitamin A—or its equivalent as beta‐carotene—can lower mortality risk related to pregnancy and childbirth, presumably by reducing the severity of conditions such as sepsis, tuberculosis, and diarrheal diseases. An adequate intake of beta‐carotene may also reduce some maternal health risks related to oxidative stress. These findings reveal the potential for vitamin A and other micronutrient interventions to improve maternal and infant health and survival. They also present important implementation challenges for the developing world.
The Morphological and Morphometric Features of the Scaphoid
Authors: CERI N. , KORMAN E. , GUNAL I. , TETIK S.
Published: May 2004

This cadaveric study used 200 scaphoid bones (100 left and 100 right) to assess 24 morphological and 11 morphometric parameters. At least one morphometric feature was absent in all scaphoids, though the tubercle and the dorsal sulcus were present in all instances. There were significant differences in the circumferences of the waist and the base of the tubercle, the width of the main sulcus and the secondary height of the tubercle between left and right scaphoids. Detailed knowledge of anatomy and correlations between the anatomical features may help better understanding of clinical problems.
The Two-Point Discrimination Test – Time For a Re-Appraisal?
Authors: LUNDBORG G. , ROSÉN B.
Published: May 2004

The two-point discrimination (2PD) test is the most frequently used test for the assessment of the sensory outcome after nerve repair. Here we focus on factors which explain the enormous and implausible variability in reported 2PD levels after nerve repair. We conclude that the 2PD testing technique is not at all standardized and that its use as the sole test for tactile gnosis recovery should be seriously questioned. Reports of 2PD results should always be accompanied by a detailed description of how the test was performed, especially with reference to the pressure applied and the testing protocol.
Risk Factors in Carpal Tunnel Syndrome
Authors: GEOGHEGAN J. M. , CLARK D. I. , BAINBRIDGE L. C. , SMITH C. , HUBBARD R.
Published: May 2004

We have undertaken a large case–control study using the UK General Practice Research Database to quantify the relative contributions of the common risk factors for carpal tunnel syndrome (CTS) in the community. Cases were patients with a diagnosis of CTS and, for each, four controls were individually matched by age, sex and general practice. Our dataset included 3,391 cases, of which 2,444 (72%) were women, with a mean age at diagnosis of 46 (range 16–96) years. Multivariate analysis showed that the risk factors associated with CTS were previous wrist fracture (OR = 2.29), rheumatoid arthritis (OR = 2.23), osteoarthritis of the wrist and carpus (OR = 1.89), obesity (OR = 2.06), diabetes (OR = 1.51), and the use of insulin (OR = 1.52), sulphonylureas (OR = 1.45), metformin (OR = 1.20) and thyroxine (OR = 1.36). Smoking, hormone replacement therapy, the combined oral contraceptive pill and oral corticosteroids were not associated with CTS. The results were similar when cases were restricted to those who had undergone carpal tunnel decompression.
Repairs of Partial Oblique Tendon Injuries: A Biomechanical Evaluation
Authors: TAN J. , MING L. , JIA Z.J. , TANG J.B.
Published: May 2004

This study evaluated the tensile properties of oblique partial tendon lacerations and the effects of peripheral sutures on their strength. Seventy-four fresh pig flexor digitorum profundus tendons were divided into eight groups and were transected across 90% of their diameter. The lacerations in the tendons of five of the groups were at 0°, 15°, 30°, 45°, and 60° to their transverse cross-section, respectively. In the other three groups the lacerations were 0°, 45°, and 60° to the cross-section and were repaired with running peripheral sutures. The tendons were subjected to load-to-failure tests in a tensile testing machine to determine the initial, 1 and 2 mm gap formation forces, and the ultimate strength. Obliquity of tendon lacerations affected the strength of partially lacerated tendons. The tendons with 45° and 60° oblique lacerations had a significantly lower ultimate strengths than those with transverse (0°), or 15° or 30° oblique lacerations. Running peripheral sutures significantly increased both the gap formation forces and the ultimate strength of the tendons with oblique partial lacerations.