bluuebunny/crossref_metadata_2025 huggingface dataset:
Borrelia burgdorferi, an extracellular pathogen, circumvents osteopontin in inducing an inflammatory cytokine response
Authors: Craig-Mylius Kathleen , Weber Georg F , Coburn Jenifer , Glickstein Lisa
Published: February 2005

A classic proinflammatory T helper cell type 1 (TH1) response directed against intracellular pathogens includes the cytokine osteopontin, which acts predominantly on macrophages, where it induces the secretion of intereukin (IL)-12 and suppresses the secretion of IL-10. As cell-mediated immune responses play an important role in the resistance to Lyme arthritis, a manifestation of infection by the extracellular pathogen Borrelia burgdorferi, we tested the hypothesis that osteopontin may be required to induce TH1 responses and inflammation. The role of osteopontin was tested in vivo and using ex vivo macrophages in B6129F3 mice susceptible to experimental Lyme arthritis. Mice of this genetic background and those fully backcrossed to C57BL/6, which lacked osteopontin expression (spp1−/−), were as susceptible to B. burgdorferi-induced arthritis as littermate controls. Furthermore, equal numbers of spirochetes, as measured by quantitative polymerase chain reaction of the B. burgdorferi gene recA in spp1−/− and B6129F3 wild-type littermates, suggested that susceptibility to infection was not dependent on this cytokine. Neither of the B6129F3 parental mouse strains lacked the ability to secrete osteopontin. spp1−/− mice and controls had immunoglobulin G2 titers, suggestive of a TH1 response. B. burgdorferi was able to directly stimulate the secretion of the proinflammatory cytokines IL-12 and tumor necrosis factor α from wild-type and spp1−/− macrophages alike. These results indicate that the usually critical role of osteopontin in the induction of cellular immune responses to intracellular pathogens was circumvented by the ability of the extracellular pathogen B. burgdorferi to induce macrophages directly to produce proinflammatory cytokines.
In vivo gene silencing (with siRNA) of pulmonary expression of MIP-2 versus KC results in divergent effects on hemorrhage-induced, neutrophil-mediated septic acute lung injury
Authors: Lomas-Neira Joanne L , Chung Chun-Shiang , Wesche Doreen E , Perl Mario , Ayala Alfred
Published: February 2005

Lung injury in trauma patients exposed to a secondary infectious/septic challenge contributes to the high morbidity/mortality observed in this population. Associated pathology involves a dys-regulation of immune function, specifically, sequestration of activated polymorphonuclear neutrophils (PMN) in the lungs. The targeting of PMN is thought to involve the release of chemokines from cells within the local environment, creating a concentration gradient along which PMN migrate to the focus of inflammation. Keratinocyte-derived chemokine (KC) and macrophage-inflammatory protein-2 (MIP-2) are murine neutrophil chemokines identified as playing significant but potentially divergent roles in the pathogenesis of acute lung injury (ALI). In the current study, we examined the contribution of local pulmonary cells to the production of KC and MIP-2 and the pathogenesis of ALI. We hypothesized that local silencing of KC or MIP-2, via the local administration of small interference RNA (siRNA) against KC or MIP-2, following traumatic shock/hemorrhage (Hem), would suppress signaling for PMN influx to the lung, thereby reducing ALI associated with a secondary septic challenge (cecal ligation and puncture). Assessment of siRNA local gene silencing was done in green fluorescent protein (GFP)-transgenic, overexpressing mice. A marked suppression of GFP expression was observed in the lung 24 h following intratracheal (i.t.) instillation of GFP siRNA, which was not observed in the liver. To test our hypothesis, siRNA against KC or MIP-2 (75 ug/C3H/Hen mouse) was instilled (i.t.) 2 h post-Hem (35 mm Hg for 90 min, 4× LRS Rx.). Twenty-four hours after, mice were subjected to septic challenge and then killed 24 h later. i.t. MIP-2 siRNA significantly (P<0.05, ANOVA-Tukey's test, n=5–6/group) reduced tissue and plasma interleukin (IL)-6, tissue MIP-2 (enzyme-linked immunosorbent assay), as well as neutrophil influx [myeloperoxidase (MPO) activity]. In contrast, KC siRNA treatment reduced plasma KC, tissue KC, and IL-6 but produced no significant reduction in plasma IL-6 or MPO. Neither treatment reduced tissue or plasma levels of tumor necrosis factor α compared with vehicle. These data support not only our hypothesis that local pulmonary chemokine production of MIP-2, to a greater extent than KC, contributes to the pathogenesis of PMN-associated ALI following Hem but also the use of siRNA as a potential therapeutic.
Strong El Niño events during the early Holocene: stable isotope evidence from Peruvian sea shells
Authors: Carrè Matthieu , Bentaleb Ilhem , Fontugne Michel , Lavallee Daniele
Published: February 2005

Intrashell oxygen and carbon stable isotope profiles (δ18O,δ13C) were established for Mesodesma donacium shells from the preceramic archaeological site, Quebrada de los Burros in coastal southern Peru, to reconstruct the sea-surface temperature (SST) variations and to estimate changes of the El Niño-Southem Oscillation (ENSO) interannual variability from the early Holocene to the present. Very strong oxygen isotopic excursions attributed to El Niño events are evident in three shells dated between 9 and 7.9 ka. This indicates that short and strong warm events were breaking the mean cooler surface conditions (2-3°C cooler compared with today SSTs) in relation with an intense upwelling system. At 4.8 ka, slightly lower mean SST (cooler than today by 0.7°C) and a reduced seasonality confirms the previous hypothesis of a weak ENSO variability at this period.
Holocene North Atlantic surface circulation and climatic variability: evidence from diatom records
Authors: Witak Malgorzata , Wachnicka Anna , Kuijpers Antoon , Troelstra Simon , Prins Maarten A. , Witkowski Andrzej
Published: February 2005

Diatom analyses have been performed on a 425cm long Holocene marine sediment sequence from the North Atlantic south of Iceland and a 920cm sediment core spanning the last c. 7500 years from Skalafjord, Faeroe Islands. Additional core data include stable isotopes and results from magnetic susceptibility measurements, while chronostratigraphic control has been provided by AMS 14C measurements. The diatom records reveal distinct changes in North Atlantic surface circulation and climate that have been correlated with published terrestrial and marine records. Initial Holocene warming is dated at 9900 14C years BP, and after a Preboreal cold spell enhanced North Atlantic Current activity and warming prevailed from 9600 to 8800 14C years BP. From 8800 to 8000 "4C years BP the advection of warm Atlantic water masses weakened, presumably under atmospheric circulation conditions characterized by a dominating negative NAO. Prior to the Holocene Climatic Optimum (6000-5000 14C years BP) distinct hydrographic gradients existed in the northern North Atlantic that were probably most pronounced during the reported '8200 cal. years BP cold event'. After 5000 "4C years BP both core records indicate increased climate instability and periods of cooling ('Neoglaciation'), with enhanced cyclone activity affecting the northern North Atlantic particularly at around 4700, 4200, 3200, 2000, 1500 and 1000 14C years BP.
Molluscan and ostracod biostrati graphy of Holocene tufa in the Test valley at Bossington, Hampshire, UK
Authors: Davies P. , Griffiths H. I.
Published: February 2005

Holocene tufa deposits in the Test valley, Hampshire, UK, have been examined as part of a wider project into prehistoric activity and landscape change in the central southern chalklands. Molluscan and ostracod analysis on three tufa sequences shows that the tufa began developing around 9300 BP in open marsh/open woodland environment. Although one of the sequences (Boss 10) demonstrates a wooded environment throughout, another sequence (Boss 360n/60e) indicates that the initial woodland is followed by reversion to more open conditions. Both profiles then show a short 'drier' woodland phase. Subsequent to this, one of the profiles then shows wetter woodland conditions developing (Boss 10), the other (Boss 360n/60e) more open wetland. Deposition rates are comparable to tufa deposits elsewhere and indicate that the short-lived 'drier' woodland phase perhaps lasted only a few hundreds of years. There are also indications of woodland clearance, associated with a charcoal peak, although no causal mechanism can be proposed. The formation of substantial portions of Holocene tufa deposits within open or only A lightly wooded landscapes has not previously been documented for southern Britain, where generally tufa HOLOCENE has been shown to have formed in densely wooded conditions. Through the tufa deposits the ostracod and RESEARCH molluscan evidence are in accord and provide detailed hydrological and environmental information respectively. Fine sampling (1 cm units) allowed a temporal resolution of perhaps around 20 years per sample. It is clear that the tufas studied here formed as groundwater-fed paludal deposits within the valley bottom.
Vegetation history in western Uganda during the last 1200 years: a sedimentbased reconstruction from two crater lakes
Authors: Ssemmanda Immaculate , Ryves David B. , Bennike Ole , Appleby Peter G.
Published: February 2005

Pollen, plant macrofossil and charcoal records from two neighbouring crater lakes (Lake Wandakara and Lake Kasenda) in lower montane (altitude-1200m) western Uganda (0.5DN, 30) reveal major changes in local and regional vegetation over the last 1200 years, which can be related to regional variations in climate (especially effective precipitation) and human impact. The biological signals are supplemented by evidence from physical sedimentary analyses (magnetic susceptibility, loss-on-ignition, dry mass accumulation rate) for major catchment changes in a wider regional context. From AD 750 to 900, medium-altitude moist forest existed around Lake Kasenda, which was largely replaced by grassland by AD 1000, coincident E _ = with evidence for increased catchment erosion and fire events, linked to human impact during a brief arid phase. Despite wetter conditions from AD 1000 to 1200 and in the 1400s, grassland prevailed around both sites until c. AD 1700-1750, with increased catchment disturbance from AD 1600 to 1700, shortly before the abandonment of major regional settlements and a switch to dispersed homesteads more reliant on pastoralism. A Both sites show the return of semi-deciduous and swamp forest from c. AD 1700 to 1800, with tree and shrub HOLOCENE pollen remaining high until the most recent times. Pollen assemblages reveal increasingly clear human impact RESEARCH on local and regional vegetation in the twentieth century, which obscures any climate signal. Pollen signals may PAPER not be sensitive to all climatic fluctuations (e.g., late eighteenth-early nineteenth-century aridity), but appear to record the varying impacts on vegetation communities of both climate and human activity over long timescales. Other proxies should be analysed to disentangle further the relative importance, and interactions, of these two major drivers of environmental change in tropical Africa in recent millennia.
‘Little Ice Age’ glacier fluctuations, Gran Campo Nevado, southernmost Chile
Authors: Koch Johannes , Kilian Rolf
Published: February 2005

Moraine systems of Glaciar Lengua (unofficial name) and neighbouring glaciers of Gran Campo Nevado (53°S) in the southernmost Andes were mapped and dated by dendrochronological means. They were formed around AD 1628, 1872/1875, 1886, 1902, 1912 and 1941 with the advance in the 1870s being calendar dated. Recessional moraines within each moraine system correspond to brief standstills or minor readvances. A significantly older moraine could not be directly dated by dendrochronological methods as the forest on it was assumed to be second-generation or older. From soil-formation rates, it is assumed that this moraine was formed at some time between AD 1280 and 1460, a time in which many other glaciers in Patagonia formed moraines. Overall, fluctuations of Glaciar Lengua show a strong synchronicity to other glaciers in the Patagonian Andes between 41°S and 55°S. This study suggests that Glaciar Lengua and possibly all glaciers of Gran Campo Nevado reached their Holocene maximum during the‘Little Ice Age.’
Late-Holocene flooding and drought in the Northern Great Plains, USA, reconstructed from tree rings, lake sediments and ancient shorelines
Authors: Shapley M. D. , Johnson W. C. , Engstrom D. R. , Osterkamp W. R.
Published: February 2005

During the AD 1990s the Waubay Lakes complex in eastern South Dakota experienced historically unprecedented high water levels. Property damage from this flooding led to an examination of the occurrence of past pluvial episodes and their relation to climate. A 1000-year hydroclimate reconstruction was developed from local bur oak (Quercus macrocarpa) tree-ring records and lake-sediment cores. Analysis of lake shoreline and drainage features provides late-Quaternary geomorphic context for this high-resolution record. Tree-ring width and shell geochemistry of the ostracode Candona rawsoni show marked coherence, indicating synchronous responses to moisture balance in vegetation and lake salinity; geomorphic evidence suggests buffering of lake-system expansion during pluvial periods by evaporative dynamics. Pluvial periods display a recurrence frequency of approximately 140-160 years over the past millennium. Prior to AD 1800, both lake highstands and droughts tended towards greater persistence than during the past two centuries. Frequency and timing of hydroclimatic oscillations show strong similarities to records from other sites in the Northern Great Plains (NGP) of North and South Dakota, and incomplete coherence with records of southern Manitoba.
The demise of the alga Botryococcus braunii from a Norwegian fjord was due to early eutrophication
Authors: Smittenberg R. H. , Baas M. , Schouten S. , Damste J.S. Sinninghe
Published: February 2005

In the sedimentary record of the permanently anoxic Drammensfjord, a suite of lipid biomarkers that are derived from the alga Botryococcus braunii (Kiutzing), botryococcenes, is present in varying amounts, but absent in sediments deposited after AD 1850. The disappearance is concurrent with the industrialization of sawmills and the introduction of paper and pulp mills along the river Drammen and upstream water bodies, and the related increase of anthropogenic eutrophication. Because of the sensitivity of this alga for environmental change, a direct correlation between these two events is inferred. This implies that the disappearance of the botryococcenes can serve as a palaeoenvironmental indicator for early eutrophication or environmental change in general. This may be a useful tool in the ongoing research to unravel the response of natural systems to climatic, geophysical or anthropogenic changes.
Text characteristics of English language university Web sites
Authors: Thelwall Mike
Published: February 2005

The nature of the contents of academic Web sites is of direct relevance to the new field of scientific Web intelligence, and for search engine and topic‐specific crawler designers. We analyze word frequencies in national academic Webs using the Web sites of three English‐speaking nations: Australia, New Zealand, and the United Kingdom. Strong regularities were found in page size and word frequency distributions, but with significant anomalies. At least 26% of pages contain no words. High frequency words include university names and acronyms, Internet terminology, and computing product names: not always words in common usage away from the Web. A minority of low frequency words are spelling mistakes, with other common types including nonwords, proper names, foreign language terms or computer science variable names. Based upon these findings, recommendations for data cleansing and filtering are made, particularly for clustering applications.
An analysis of the relative hardness of Reuters‐21578 subsets
Authors: Debole Franca , Sebastiani Fabrizio
Published: February 2005

The existence, public availability, and widespread acceptance of a standard benchmark for a given information retrieval (IR) task are beneficial to research on this task, because they allow different researchers to experimentally compare their own systems by comparing the results they have obtained on this benchmark. The Reuters‐21578 test collection, together with its earlier variants, has been such a standard benchmark for the text categorization (TC) task throughout the last 10 years. However, the benefits that this has brought about have somehow been limited by the fact that different researchers have “carved” different subsets out of this collection and tested their systems on one of these subsets only; systems that have been tested on different Reuters‐21578 subsets are thus not readily comparable. In this article, we present a systematic, comparative experimental study of the three subsets of Reuters‐21578 that have been most popular among TC researchers. The results we obtain allow us to determine the relative hardness of these subsets, thus establishing an indirect means for comparing TC systems that have, or will be, tested on these different subsets.
Effects of process stability on anaerobic biodegradation of LAS in UASB reactors
Authors: Løbner Trine , Toräng Lars , Batstone Damien John , Schmidt Jens Ejbye , Angelidaki Irini
Published: February 2005

Anaerobic biodegradation of linear alkylbenzene sulfonates (LAS) was studied in upflow anaerobic sludge blanket (UASB) reactors operated under mesophilic (37°C) and thermophilic (55°C) conditions. LAS C12 concentration in the influents was 10 mg·L−1, and the hydraulic retention time in the reactors was 2 days. Adsorption of LAS C12 was assessed in an autoclaved control reactor and ceased after 115 days. The reactors were operated for a minimum of 267 days; 40–80% removal of LAS C12 was observed. A temperature reduction from 55°C to 32°C for 30 h resulted in process imbalance as indicated by increase of volatile fatty acids (VFA). The imbalance was much more intense in the LAS amended reactor compared with an unamended reactor. At the same time, the process imbalance resulted in discontinued LAS removal. This finding indicates that process stability is a key factor in anaerobic biological removal of LAS. After a recovery period, the removal of LAS resumed, providing evidence of biological anaerobic LAS degradation. The removal remained constant until termination of experiments in the reactor. Biodegradation of LAS in the mesophilic reactor was at the same level as in the thermophilic reactor under stable conditions. ©2005 Wiley Periodicals, Inc.
Role of nutrient supply on cell growth in bioreactor design for tissue engineering of hematopoietic cells
Authors: Pathi Pragyansri , Ma Teng , Locke Bruce R.
Published: February 2005

In the present study, a dynamic mathematical model for the growth of granulocyte progenitor cells in the hematopoietic process is developed based on the principles of diffusion and chemical reaction. This model simulates granulocyte progenitor cell growth and oxygen consumption in a three‐dimensional (3‐D) perfusion bioreactor. Material balances on cells are coupled to the nutrient balances in 3‐D matrices to determine the effects of transport limitations on cell growth. The method of volume averaging is used to formulate the material balances for the cells and the nutrients in the porous matrix containing the cells. All model parameters are obtained from the literature. The maximum cell volume fraction reached when oxygen is depleted in the cell layer at 15 days and is nearly 0.63, corresponding to a cell density of 2.25 × 108 cells/mL. The substrate inhibition kinetics for cell growth lead to complex effects with respect to the roles of oxygen concentration and supply by convection and diffusion on cell growth. Variation in the height of the liquid layer above the cell matrix where nutrient supply is introduced affected the relative and absolute amounts of oxygen supply by hydrodynamic flow and by diffusion across a gas permeable FEP membrane. Mass transfer restrictions of the FEP membrane are considerable, and the supply of oxygen by convection is essential to achieve higher levels of cell growth. A maximum growth rate occurs at a specific flow rate. For flow rates higher than this optimal, the high oxygen concentration led to growth inhibition and for lower flow rates growth limitations occur due to insufficient oxygen supply. Because of the nonlinear effects of the autocatalytic substrate inhibition growth kinetics coupled to the convective transport, the rate of growth at this optimal flow rate is higher than that in a corresponding well‐mixed reactor where oxygen concentration is set at the maximum indicated by the inhibitory kinetics. ©2005 Wiley Periodicals, Inc.
Comprehensive thermal optimization of liquid composite molding to reduce cycle time and processing stresses
Authors: Ruiz Edu , Trochu François
Published: February 2005

Liquid composite molding (LCM) is a well‐established and flexible composite manufacturing technology capable of producing large parts at a relatively low cost. In this family of related injection processes, a large number of design variables have strong impact on manufacturing performance. The determination of adequate process parameters is key to yield successful molding conditions and reduce cycle time. In addition, properties and durability of composite parts are strongly affected by internal stresses. Excessive stress levels may lead to important defects in the part at the curing stage and after processing, when the part is cooled to room temperature. In this investigation, a comprehensive curing optimization algorithm is proposed to reduce internal stresses during composite processing. This study focuses on the minimization of the macroscopic residual stresses that appear during cure and cooling in thermoset composite laminates as a result of temperature and degree of cure gradients. The proposed fitness function to be minimized is based on the physics of the matrix material transformation and on the mechanical behavior of the composite material. An evolutionary strategy based on genetic algorithms (GA) is implemented for the minimization of the fitness function. Optimization is carried out for thin and thick glass/polyester laminated composites. Different optimization schemes with thermo‐elastic and viscoelastic models of the composite mechanical properties are studied. The advantages and drawbacks of each model are stated and discussed. POLYM. COMPOS., 26:209–230, 2005. © 2005 Society of Plastics Engineers
Computational fluid dynamics applied to the vacuum infusion process
Authors: Andersson H.M. , Lundström T.S. , Langhans N.
Published: February 2005

An all‐purpose computational fluid dynamics software is used for simulations of the vacuum infusion process. The study comprises simulations of a full three‐dimensional two‐phase flow through a porous medium. The medium that has an anisotropic, spatial‐ and time‐dependent permeability is located in a complex mold with moving boundaries. With this generalization, different material combinations, processing conditions, and even other manufacturing techniques can be evaluated. The strength of the presented approach is exemplified by simulations of mold filling of a real part, using a typical vacuum infusion set‐up. In addition to the overall development of the model, a number of specific aspects and phenomena are investigated and evaluated. Local lead of the flow front and a minor influence in overall flow front lead‐lag, with no influence on the fill time, is the result of simulations of edge effects due to poor preform fitting. POLYM. COMPOS., 26:231–239, 2005. © 2005 Society of Plastics Engineers
Entry mechanisms of enveloped viruses. Implications for fusion of intracellular membranes
Authors: Hoekstra Dick , Kok Jan Willem
Published: February 2005

Enveloped viruses infect cells by a mechanism involving membrane fusion. This process is mediated and triggered by specific viral membrane glycoproteins. Evidence is accumulating that fusion of intracellular membranes, as occurs during endocytosis and transport between intracellular organelles, also requires the presence of specific proteins. The relevance of elucidating the mechanisms of virus fusion for a better understanding of fusion of intracellular membranes is discussed.
Studies on the mechanism of action of a bilayer stabilizing inhibitor of protein kinase C: Cholesterylphosphoryldimethylethanolamine
Authors: Epand Richard M. , Stafford Alan R. , Bottega Remo , Ball Eric H.
Published: February 2005

Cholesterylphosphoryldimethylethanolamine is a zwitterionic compound which is a good bilayer stabilizer. As has been found with many other compounds having these properties, cholesterylphosphoryldimethylethanolamine is found to be a potent inhibitor of protein kinase C in both vesicle and micelle assay systems. The kinetics of the inhibition in Triton X-100 micelles was non-competitive with respect to ATP, histone, diolein, phorbol ester and Ca2+. It has a Ki of about 30 μm. The inhibition kinetics as a function of phosphatidylserine concentration is more complex but suggestive of competitive inhibition. Cholesterylphosphoryldimethylethanolamine does not prevent the partitioning of protein kinase C into the membrane. This inhibitor lowers the Ca2+-phosphatidylserine-independent phosphorylation of protamine sulfate by protein kinase C and directly affects the catalytic segment of the enzyme generated by tryptic hydrolysis. Thus, this zwitterionic bilayer stabilizing inhibitor of protein kinase C both competes with the binding of phosphatidylserine as well as affects the active site of protein kinase C.
Purification of the rabbit small intestinal sucrase-isomaltase complex: Separation from other maltases
Authors: Vasseur Monique
Published: February 2005

The rabbit intestinal sucrase-isomaltase complex has been purified to homogeneity after solubilization with Triton X 100 followed by chromatography on DEAE Sepharose CL 6B and a second solubilization with papain. After hydrophobic chromatography on Octyl Sepharose CL 6B, separation from other contaminating maltases was achieved by gel filtration on Ultrogel ACA 22. The final enzyme was purified 390 fold, with a specific activity of about 10 units per mg protein.
Involvement of protein kinase A and casein kinase II in the in vivo protein kinase activities in prophase arrested Xenopus oocytes
Authors: cormier Patrick , Mulner-Lorillon Odile , Ozon René , Bellé Robert
Published: February 2005

In vivo β casein phosphorylation was analysed in Xenopus full-grown oocytes arrested in the prophase of the meiotic cell division. The phosphorylation was inhibited by the protein kinase inhibitor (PKI) and also by heparin (3 μg/ml; final concentration). β casein phosphorylation was increased by spermine (2 mM). Therefore, protein kinase A and casein kinase II are both active in vivo in full-grown oocytes and may be involved in the prophase arrest of meiotic cell division.
Thymus involution induced by 5-azacytidine
Authors: Csordas Adam , Schauenstein Konrad
Published: February 2005

Hypomethylation of DNA, which can be achieved by incorporation of 5-azacytidine, has been correlated with derepression of genes. In order to examine the in vivo effects of 5-azacytidine on organ development and differentiation, young rats were treated with the drug. There was an almost complete reduction of thymus and a marked reduction of spleen weight, while other organs, including testes were only marginally affected. Control experiments with cytosine-arabinoside suggest that treatment with an inhibitor of DNA replication per se is not responsible for the very rapid thymus involution triggered by 5-azacytidine in rats. In spite of the drastic reduction of thymus and spleen weight, lymphocytes of these organs were not impaired in their response to the T cell mitogen Concanavalin A.
Oxytocin and vasopressin stimulate inositol phosphate production in human gestational myometrium and decidua cells
Authors: Schrey Michael P. , Read Alison M. , Steer Philip J.
Published: February 2005

The involvement of phosphoinositide hydrolysis in the action of oxytocin and vasopressin on the uterus was investigated in gestational myometrium and decidua cells by measuring the production of inositol phosphates. Both peptides stimulated a dose related increase in all three inositol phosphates in myometrium. This may be related to the control of sarcoplasmic Ca++ levels in the myometrium. Oxytocin and vasopressin also stimulated inositol 1-phosphate (IP) production in decidua cells. The hydrolysis of phosphatidylinositol by decidua homogenates exhibited a precursor-product relationship for diacylglycerol and arachidonic acid accumulation. Hence both peptides may mobilise free arachidonic acid, for prostaglandin biosynthesis, from decidua cell phosphoinositides by the sequential action of phospholipase C and diacylglycerol lipase.
Isolation of repetitive clones from human muscle cDNA library
Authors: Bober Eva , Singh Surjit , Agarwal Dharam P. , Goedde H. Werner
Published: February 2005

Human fetal muscle cDNA library was screened with a β-myosin heavy chain gene fragment containing Alu sequences. Two cDNA clones AI and BII with 1.8 and 3 kb inserts respectively were chosen for further characterization by means of RNA and DNA hybridization procedures and sequencing. The clones appeared to contain repetitive sequences as well as single copy regions. They are actively transcribed in different stages of myogenic development but not in the liver. DNA sequence analysis of short stretches from both clones revealed no sequence homology to any other published DNA sequences.
Virus replication inhibitory peptide inhibits the conversion of phospholipid bilayers to the hexagonal phase
Authors: Epand Richard M.
Published: February 2005

Virus replication inhibitory peptide (carbobenzoxy-D-Phe-L-PheGly) was shown to be a potent specific inhibitor of the replication of paramyxovirus and myxovirus (Richardson, Scheid and Choppin (1980), Virology105, 205–222). This peptide inhibits the membrane fusing activity of a viral glycoprotein.

Many agents which promote the formation of the hexagonal phase in membranes also accelerate membrane fusion. At a mole fraction of 0.1, viral replication inhibitory peptide can raise the bilayer to hexagonal phase transition temperature of dielaidoylphosphatidylethanolamine by almost 10°. Two related peptides, carbobenzoxy-L-PheGly and carbobenzoxy-L-GlyPhe, are less potent in raising the bilayer to hexagonal phase transition temperature, with the latter peptide being the least effective of the three. This order of potency is the same as the order of potency in inhibiting viral replication. Substances which inhibit hexagonal phase formation of pure lipids may also inhibit membrane fusion.
Brown adipose tissue activity in hypocaloric-diet fed lactating rats
Authors: Villarroya Francesc , Felipe Antonio , Mampel Teresa
Published: February 2005

Hypocaloric diet feeding reduced the mitochondrial protein content and whole tissue GDP-binding in interscapular brown adipose tissue from both virgin and lactating rats. A reduction in brown fat lipoprotein lipase activity was also detected in underfed virgin and lactating animals. These results indicate that lactation in the rat, even though it produces a reduction in brown fat activity, does not impair the capacity of the tissue to respond to a diminished caloric intake by lowering its activity further.
Quantitative analysis of metabolite levels in normal human subjects by 31P topical magnetic resonance
Authors: Dawson M. Joan
Published: February 2005

The results we have obtained on forearm muscles of normal human subjects are complementary to those on isolated frog muscle and they lead, to the same conclusions. We are satisfied that our31P TMR measurements of [P-metabolites] in normal subjects are reliable, and we are now extending these methods for use in cases of degenerative muscular disorders (Edwards et al., 1982). Chemical estimates of [ADP] and [AMP] are not directly relevant to metabolic studies, and so an important contribution of NMR to the study of muscular mechanisms is its ability to estimate the concentrations of these metabolites that are free to take part in metabolic reactions.
Glutamine uptake by rat renal basolateral membrane vesicles
Authors: Reynolds Robert A. , Wald Hanna , Segal Stanton
Published: February 2005

The presence of a sodium-dependent, saturable uptake process is described in basolateral membranes of rat renal cortex for L-glutamine. Concentration-dependence studies indicate the presence of multiple transport systems with Km1 of 0.032 mM and V1 of 0.028 nmol/mg of protein per min, and Km2 of 17.6 mM and V2 of 17.6 nmol/mg of protein per min. Lysine completely inhibits the high-affinity, low-capacity Km system and partially inhibits the low-affinity, high-capacity system. Cystine and other dibasic amino acids also affect glutamine uptake.
Inhibition by nojirimycin and 1-deoxynojirimycin of microsomal glucosidases from calf liver acting on the glycoprotein oligosaccharides Glc1–3Man9GlcNAc2
Authors: Hettkamp Harald , Bause Ernst , Legler Günter
Published: February 2005

Particulate membrane fractions from calf liver catalyze the release of glucose from GlcNAc2-Man9-Glc1–3-oligosaccharides. Maximal oligosaccharide-glucosidase activity was obtained at pH 6.2 and a detergent concentration of 0.5% Triton X-100. This activity could be distinguished from non-specific α-glucosidase activity on the basis of different pH-dependence and lack of activation by detergent. The relative rates for the hydrolysis of the Glc3-, Glc2-, and Glcl-oligosaccharide, estimated from the initial velocity, was 1: 12: 3. There is no significant difference in the enzyme activity towards free, peptide-bound, or lipid-linked oligosaccharide.

Nojirimycin and l-deoxynojirimycin were strong inhibitors of microsomal oligosaccharide-glucosidases. Hydrolysis of GIc3-oligosaccharide was inhibited by 50% at concentrations of 0.16 mM and 2 μM, respectively. Hydrolysis of the Glc2- and Glc1-oligosaccharide was inhibited to a somewhat lower extent, suggesting the presence of at least two glucosidases, one acting on Glc3- and one acting on Glc1- and Glc2-oligosaccharide.
Cystine uptake by rat jejunal brushborder membrane vesicles
Authors: Ožegović Božena , McNamara Pamela D. , Segal Stanton
Published: February 2005

The presence of a sodium-stimulated, saturable uptake process for L-cystine is described in brushborder membrane vesicles isolated from rat jejunal mucosa. Concentration-dependence studies indicate the presence of a single transport system for cystine with Km = 0.053 mM and Vmax = 0.633 nmol/mg/15 s. Lysine completely inhibits the uptake of cystine.
Lanthanide-ion transport across phospholipid vesicular membranes: a comparison of alamethicin 30 and A23187 using 1H-NMR spectroscopy
Authors: Hunt G. R. A. , Jones I. C.
Published: February 2005

The kinetics of Pr3+ transport by the ionophores alamethicin 30 and A23187 across unilamellar phospho-lipid vesicular membranes has been compared by following the time-dependent changes in the 1H-NMR spectrum of the vesicles. The measured rates of transport allow stoichiometries of the transporting species to be deduced which are consistent with channel- and carrier-mediated mechanisms respectively. The method provides a useful complement to planar bilayer conductivity studies of these systems.
Coagulation factor III (tissue factor) interaction with phospholipid vesicles induced by cadmium: characterization of the reconstituted protein-membrane complex
Authors: Carson Steven D. , Konigsberg William H.
Published: February 2005

Coagulation factor III (tissue factor) is a membrane glycoprotein which serves as a cofactor in the proteolytic activation of factor X and factor IX by factor VIIa. Mixing of human placental factor III apoprotein with vesicles of bovine brain phospholipids does not produce significant reconstitution of factor III activity, but, when the mixture of apoprotein and vesicles is made 5 mM with CdCI2, the apoprotein is incorporated into the vesicles. Ultracentrifugation on sucrose density gradients demonstrated that the active factor III-lipid complex formed by reconstitution with vesicles had a density indistinguishable from that of the complex formed by detergent dialysis. Vesicles isolated after centrifugation were shown to range in diameter from 20 nm to over 100 nm using the electron microscope. Gel filtration showed that factor-III activity was associated with all size-classes of vesicles. The presence of factor III activity in the smaltest vesicles argues for a specific cadmium-mediated reconstitution of the apoprotein with phospholipid vesicles.
The use of antiserum with specific reactivity toward fat-cell surface antigen(s) to follow the progression of 3T3-L1 preadipocyte differentiationin vitro
Authors: Plaas Hedwig A. K. , Woodhead J. Stuart , Cryer Anthony
Published: February 2005

Using an i n d i r e c t, labelled-second-antibody cellular immunoassay technique, an adipocyte-specific antiserum haS been investigated. Components of the antiserum were shown to bind to differentiated 3T3-L1 cells; the cellular capacity for binding increased progressively during the induced differentiation of these ceils in vitro.
Enzyme induction in rat liver: The effects of Be2+in vivo
Authors: Ord Margery G. , Stocken Lloyd A.
Published: February 2005

Rats given an LD50 dose of Be2+ showed reduced activities of ornithine decarboxytase and tyrosine aminotransferase in liver in response to dexamethasone induction. Control fed animals showed ‘superinduction’. Be2+ also inhibited the uptake of [3H]orotic acid into rapidly labelled RNA of ribonucleoprotein particles extracted from liver nuclei in isomolar solutions at pH 8.0. Consistent with inhibition of cytoplasmic protein kinase reported previously (Kaser et at., 1980), the uptake of [32P]Pi into proteins in the ribonucleoprotein particles was also diminished.
The use of the restriction endonuclease DdeI for mapping related DNAs
Authors: Buluwela L. , Malcolm A. D. B. , Coleman D. V. , Gardner S. D.
Published: February 2005

Restriction endonuclease mapping of BK virus strain GS using DdeI has allowed us to correct and extend the previously published map.
Analysis of a restriction endonuclease map for bovine papillomavirus type 2 DNA
Authors: Potter Harold L. , Murphy Michael F. , Abraham John M. , Morgan Don M. , Meinke William J.
Published: February 2005

A physical map was constructed for bovine papillomavirus type 2 DNA by the use of restriction endonucleases. A comparison between the genomes of bovine papillomavirus types I and 2 in regard to location and number of cleavage sites of seven enzymes is also presented. This comparison revealed similarities between the two genomes.
Membrane receptors in the gastrointestinal tract
Authors: Gespach Christian , Emami Shahin , Chastre Eric
Published: February 2005

This review focusses on the roles that membrane receptors and their transducers play in the physiology and pathology of the gastrointestinal tract. The multifactorial: factorial regulation of mucosal growth and function is discussed in relation to the heterogeneity of exocrine and endocrine populations that originate from progenitor cells in stomach and intestine.
Dynamic changes in plasma membrane properties of semliki forest virus infected cells related to cell fusion
Authors: Kempf C. , Michel M. R. , Kohler U. , Koblet H. , Oetliker H.
Published: February 2005

The mechanism of the processes leading to membrane fusion is as yet unknown. In this report we demonstrate that changes in membrane potential and potassium fluxes correlate with Semliki Forest virus induced cell-cell fusion at mildly acidic pH. The changes observed occur only at pH's below 6.2 corresponding to values required to trigger the fusion process. A possible role of these alterations of the plasma membrane related to membrane fusion phenomena is discussed.
A highly sensitive northern blot assay detects multiple proenkephalin a-like mRNAs in human caudate nucleus and pheochromocytoma
Authors: Monstein Hans-Jürg , Geijer Thomas
Published: February 2005

Total RNA from post mortem human caudate nucleus, cerebellum, cerebral cortex and pheochromocytoma tissues has been prepared. Northern blot analysis, using a single-stranded human proenkephalin A antisense probe (cRNA), revealed the existence of two different proenkephalin A-like sequences in the human caudate nucleus and pheochromocytoma RNA extracts of approximately 1400 and 1000 nucleotides in length respectively, whereas no specific RNA bands could be detected in the cortex and only the 1400 nucleotide band was present in the cerebellum. Under highly stringent hybridization conditions, the proenkephalin A-like RNA bands still appear, indicating that the detected RNA species have either identical or a closely related sequence to that of the wellcharacterized human proenkephalin A mRNA sequence.
Gonadotropin regulation of rat ovarian lysosomes: Existence of a hormone specific dual control mechanism
Authors: Dhanasekaran N. , Moudgal N. R.
Published: February 2005

Gonadotropic hormones PMSG (15 IU/rat), FSH (3 μg/rat), LH (9 μg/rat) and hCG (3 μg/rat) were shown to decrease the free cytosolic lysosomal enzymes during the acute phase of hormone action in rat ovaries. When isolated cells from such rats were analyzed for the cathepsin-D activity, the granulosa cells of the ovary showed a reduction in the free as well as in the total lysosomal enzyme activities in response to FSH/PMSG; the stromal and thecal compartment of the ovary showed a reduction only in the free activity in response to hCG/PMSG. The results suggest the presence of two distinct, target cell specific, mechanisms by which the lysosmal activity of the ovary is regulated by gonadotropins.
An effective method for the separation of insulin-like growth factors 1 and 2 during the purification process
Authors: Tally M. , Florell K. , Enberg G.
Published: February 2005

The separation of human insulin-like growth factors hIGF-1 and hIGF-2 was greatly improved by an additional purification step using the cation exchanger Mono-S (FPLC) compared to previous studies. Cross-reactions between hIFG-1 and hIGF-2 were strongly reduced. The more highly purified hIGF-1 had a cross-reaction of less than 1% in the RIA for hIGF-2, and was equivalent to recombinant hIGF-1. The pure hIGF-2 had a cross-reaction of less than 1% in the RIA for hIGF-1. In the human placental hIGF-2 radioreceptor assay, the hIGF-1 polypeptide competed less than 1% with hIGF-2 when the type 1 IGF receptor was blocked with insulin.
Oxidation, photosensitized by certain diketones, of enzymes and protection against such oxidation by histidine derivatives
Authors: Mäkinen K. K. , Mäkinen P.-L.
Published: February 2005

Bovine milk lactoperoxidase, eel acetylcholinesterase, and Aeromonas aminopeptidase were photooxidized and inactivated in broad-spectrum visible light in the presence of 2,3-butanedione and l-phenyl-l,2-propanedione. Methylglyoxal caused similar effects at 25zt nm. 2-Thiol-L-histidine and 3-methyl-L-histidine protected the enzymes against photoinactivation more effectively than N3−, even at a molar ratio of 2:1 (protector to enzyme). These compounds also delayed the photoinactivation of acetylcholinesterase, induced by ultraviolet light.
Enzymatic HCO3− fixation: A common mechanism for all enzymes involved?
Authors: Rubio Vicente
Published: February 2005

Conclusion

Present evidence is highly suggestive of a stepwise mechanism with a common initial step of HCO3− activation, for all enzymes that use HCO3− rather than CO2 as the substrate. This activated form of HCO3− appears to be the carbonic-phosphoric anhydride, although this has only been proved rigorously with carbamoyl phosphate synthetase. Further studies using isotope scrambling and other techniques will be necessary to establish conclusively that this is the case with the other enzymes.
The α2 cDNA sequence of human haptoglobin carries a bacterial promoter functional in vivo
Authors: van der Straten Ariane , Loriau Rosette , Herzog Albert , Bollen Alex
Published: February 2005

Various constructions of human haptoglobin (Hp) cDNA coding either for the complete α2FSβ precursor protein or only for the β subunit have been placed under the control of the λPR promoter in the bacterial expression vector pCQV2 (Queen, 1983). In addition to the expected 45,000 dalton polypeptide synthesized after induction of the PR promoter, the complete α2FSβ constructions constitutively express a smaller polypeptide of ∼30,000 dalton corresponding to a truncated Hp protein. Computer analysis of the HpcDNA revealed the presence of two strong potential bacterial promoters (α2PF and α2PS) located in the duplicated α2FS sequence. Both Hp promoter signals are followed by potential mRNA start sites and ribosome binding sites at a compatible distance from initiation codons. In addition, the Hpα2 cDNA sequence, when fused upstream to the cDNA coding for α1-antitrypsin, constitutively promotes in vivo the efficient expression of an hybrid protein specifically recognized by antibodies raised against α1-antitrypsin or haptoglobin.
Precursors of mesotocin and vasotocin in birds: Identification of VLDV- and MSEL-neurophysins in chicken, goose, and ostrich
Authors: Chauvet Marie-Thérèse , Lévy Brigitte , Michel Gilles , Chauvet Jacqueline , Acher Roger
Published: February 2005

Precursors of neurohypophysial hormones are small proteins processed into nonapeptide hormones and neurophysins during axonal transport to the neurohypophysis. In mammals, oxytocin is associated with VLDV-neurophysin and vasopressin with MSEL-neurophysin. In birds, mesotocin and vasotocin are found instead of mammalian oxytocin and vasopressin. From goose, chicken and ostrich posterior pituitary glands, two types of neurophysins related to mammalian VLDV-and MSEL-neurophysins, respectively, have been identified by their N-terminal sequences. It is assumed that, as in mammals, hormonal peptide and the first 9 residues of the corresponding neurophysin are encoded by a common exon and that mesotocin and vasotocin, evolutionary predecessors of oxytocin and vasopressin, are associated in the precursors with VLDV-neurophysin and MSEL-neurophysin, respectively.
Selective precipitation of phosphofructokinase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase from rat erythrocyte hemolysates by polyethylene glycol
Authors: Tejedor M. C. , Delgado C. , Rubio A. , Luque J.
Published: February 2005

Precipitation profiles of phosphofructokinase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase have been established in the range of 0–16% PEG at different pH (5–7) values. Precipitation generally occurred between narrow limits of polyethylene glycol. The polymer concentration needed to reach any level of enzyme precipitation is dependent on pH. Particular conditions (% PEG and pH) for the selective enzyme enrichment have been determined.
Enhanced production of dolichol, but not dolichyl phosphate, in the earliest stages of rat liver regeneration
Authors: Marino M. , Bruscalupi G. , Spagnuolo S. , Leoni S. , Mangiantini M. T. , Trentalance A. , Hemming F. W.
Published: February 2005

The regenerating liver presents a changed ability to use mevalonate 16 hr after partial hepatectomy. The dolichol content and its synthesis from mevalonate is increased, while no variation of dolichyl-P and ubiquinone parameters are detectable.

The greater amount ofmevalonate utilized to form dolichol, but not dolichyl-P, in this proliferating system, raises some questions about the physiological significance of these isoprenoid compounds and about their biosynthetic sequence.
Studies of hormone evolution. Can non-hormone oligopeptides induce a functional imprinting?
Authors: Csaba G. , Darvas Zsuzsa
Published: February 2005

Certain non-hormone oligopeptides have a greater imprinting effect on Tetrahymena than others. The imprinting potential is unrelated to the length of the peptide chain, but seems greatly dependent on the amino acid sequence. The direct growth-stimulant action developed by the peptides at the first interaction is unrelated to their imprinting effect.