bluuebunny/crossref_metadata_2025 huggingface dataset:
Global and Local PLS Regression Models to Predict Vapor Pressure
Authors: Öberg Tomas , Liu Tao
Published: July 2007

The vapor pressure is a key property in determining the distribution and fate of environmentally relevant compounds, but experimental determinations are only available for a limited number of the chemicals in current commercial use. Despite experimental efforts there is a need for estimation methods. The liquid or subcooled liquid vapor pressures at 298.15 K were collected from the literature for a diverse set of 1340 organic compounds. Theoretical molecular descriptors were derived after optimization to low‐energy conformations and used to investigate the performance of global and local Quantitative Structure–Property Relationships (QSPR). A global PLSR model with ten latent variables was found to be optimal. The predictive performance of this model, within the domain of applicability, was estimated at n=420, Q2Ext=0.980, and RMSEP=0.410 (log Pa). This model can be used in conjunction with other estimation models to assess the potential for a long range atmospheric transport.
Hypothesis testing in functional linear regression models with Neyman's truncation and wavelet thresholding for longitudinal data
Authors: Yang Xiaowei , Nie Kun
Published: July 2007

Longitudinal data sets in biomedical research often consist of large numbers of repeated measures. In many cases, the trajectories do not look globally linear or polynomial, making it difficult to summarize the data or test hypotheses using standard longitudinal data analysis based on various linear models. An alternative approach is to apply the approaches of functional data analysis, which directly target the continuous nonlinear curves underlying discretely sampled repeated measures. For the purposes of data exploration, many functional data analysis strategies have been developed based on various schemes of smoothing, but fewer options are available for making causal inferences regarding predictor–outcome relationships, a common task seen in hypothesis‐driven medical studies. To compare groups of curves, two testing strategies with good power have been proposed for high‐dimensional analysis of variance: the Fourier‐based adaptive Neyman test and the wavelet‐based thresholding test. Using a smoking cessation clinical trial data set, this paper demonstrates how to extend the strategies for hypothesis testing into the framework of functional linear regression models (FLRMs) with continuous functional responses and categorical or continuous scalar predictors. The analysis procedure consists of three steps: first, apply the Fourier or wavelet transform to the original repeated measures; then fit a multivariate linear model in the transformed domain; and finally, test the regression coefficients using either adaptive Neyman or thresholding statistics. Since a FLRM can be viewed as a natural extension of the traditional multiple linear regression model, the development of this model and computational tools should enhance the capacity of medical statistics for longitudinal data. Copyright © 2007 John Wiley & Sons, Ltd.
Qualification of safety‐critical systems in TVO nuclear power plants
Authors: Halminen Juha , Nevalainen Risto
Published: July 2007

Teollisuuden Voima Oy (TVO) operates two nuclear power plant units in Finland and has started to build a third one. The current nuclear power units have to continuously maintain and update existing instrumentation and control systems (I&C). Each new device will have to be classified and qualified according to its safety requirements. Using modern technology means in practice that more and more components have programmable features. The reliability of such components has proved to be difficult to demonstrate because of the nature of flaws in the software. Standards and rules given by authorities set the acceptance criteria for the components used in the safety systems of nuclear power plants. As a result of this trend, there is a clear need for an integrated and effective method to qualify software‐intensive I&C systems in nuclear power plant units. The integration has three major areas: (i) definition and harmonization of requirements for software‐intensive systems at different safety classes, (ii) integration of several approaches such as Software Process Improvement and Capability dEtermination (SPICE) and Failure Mode, Effects and Criticality Analysis method (FMECA) to improve confidence in qualification and (iii) integration of the system acquisition and qualification processes to improve the total effectiveness of the acquisition, delivery and deployment processes. The integrated qualification method is called the TVO SoftWare Evaluation Procedure (SWEP). It consists of a detailed qualification process and related methods for safety category B and C (IEC 61226) and Finnish safety class 3 qualifications. TVO will use the TVO SWEP method to evaluate suppliers and the conformance of their products/systems against requirements. It has been used in several cases, and it seems to save a lot of qualification resources compared to traditional methods. Copyright © 2007 John Wiley & Sons, Ltd.
An analysis of the correlations between the turbulent flow and the sound pressure fields of subsonic jets
Authors: BOGEY C. , BAILLY C.
Published: July 2007

Noise generation is investigated in subsonic isothermal round jets at Mach numbers M = 0.6 and M = 0.9, with Reynolds numbers ReD = 1700 and ReD ≥ 105, using causality methods on data provided by large-eddy simulations. The correlations between broadband sound pressure signals and broadband turbulence signals along the jet axis and the shear layer are calculated. The normalized correlations are found to be significant between the pressure emitted in the downstream direction and centreline flow quantities. They are much smaller in the cases involving flow quantities along the shear layer, and fall for large emission angles. The maximum correlations obtained between centreline turbulence and downstream sound pressure are observed just at the end of the potential core for time delays corresponding to the times of propagation evaluated along ray paths. They also appear to be lower as the Mach number is reduced, and to be enhanced as the Reynolds number is decreased. These correlation levels can reasonably be attributed to the noise source which is predominant at small emission angles. This source is therefore located on the jet centreline at the end of the potential core, in a flow region which is shown to be characterized by a dominant Strouhal number over a large axial distance, by a strong level of intermittency, and by a high convection velocity. This supports the contention that the downstream jet-noise component is connected to the periodic and intermittent intrusion of vortical structures into the jet core.
Three-dimensional shock tube flows for dense gases
Authors: GUARDONE ALBERTO
Published: July 2007

The formation process of a non-classical rarefaction shock wave in dense gas shock tubes is investigated by means of numerical simulations. To this purpose, a novel numerical scheme for the solution of the Euler equations under non-ideal thermodynamics is presented, and applied for the first time to the simulation of non-classical fully three-dimensional flows. Numerical simulations are carried out to study the complex flow field resulting from the partial burst of the shock tube diaphragm, a situation that has been observed in preliminary trials of a dense gas shock tube experiment. Beyond the many similarities with the corresponding classical flow, the non-classical wave field is characterized by the occurrence of anomalous compression isentropic waves and rarefaction shocks propagating past the leading rarefaction shock front. Negative mass flow through the rarefaction shock wave results in a limited interaction with the contact surface close to the diaphragm, a peculiarity of the non-classical regime. The geometrical asymmetry does not prevent the formation of a single rarefaction shock front, though the pressure difference across the rarefaction wave is predicted to be weaker than the one which would be obtained by the complete burst of the diaphragm.
Inertial instability in rotating and stratified fluids: barotropic vortices
Authors: KLOOSTERZIEL R. C. , CARNEVALE G. F. , ORLANDI P.
Published: July 2007

The unfolding of inertial instability in intially barotropic vortices in a uniformly rotating and stratified fluid is studied through numerical simulations. The vortex dynamics during the instability is examined in detail. We demonstrate that the instability is stabilized via redistribution of angular momentum in a way that produces a new equilibrated barotropic vortex with a stable velocity profile. Based on extrapolations from the results of a series of simulations in which the Reynolds number and strength of stratification are varied, we arrive at a construction based on angular momentum mixing that predicts the infinite-Reynolds-number form of the equilibrated vortex toward which inertial instability drives an unstable vortex. The essential constraint is conservation of total absolute angular momentum. The construction can be used to predict the total energy loss during the equilibration process. It also shows that the equilibration process can result in anticyclones that are more susceptible to horizontal shear instabilities than they were initially, a phenomenon previously observed in laboratory and numerical studies.
INFLUENCE OF SOILS AND TOPOGRAPHIC GRADIENTS ON TREE SPECIES DISTRIBUTION IN A BRAZILIAN ATLANTIC TROPICAL SEMIDECIDUOUS FOREST
Authors: Ferreira-Júnior W. G. , Silva A. F. , Schaefer C. E. G. R. , Meira Neto J. A. A. , Dias A. S. , Ignácio M , Medeiros M. C. M. P.
Published: July 2007

AbstractThis study investigated the effect of environmental variables such as soil class, soil water availability, topography and slope on spatial distribution patterns of tree species in a Brazilian Seasonal Semideciduous Forest area. Floristic and structural data for a tree community were obtained by sampling 100 plots 10 × 10 m in which every tree with trunk diameter (dbh) ⩾ 4.77 cm at 130 cm above ground level was sampled. The area under study showed a marked soil gradient, directly associated with the topography: flat hilltops with Al3+-rich Dystric Latosols give way to steep colluvial slopes with shallower and more Dystric Cambic Latosols without Al3+, changing over, at the bottom of the hollows, to Epieutrophic Cambisols richer in nutrients. The floristic-sociological parameters analysed for the soil habitats did not differ statistically from each other. The diversity and equability indices were 3.6 and 0.84, 3.48 and 0.85, 3.49 and 0.84 for the Dystric Latosol, Dystric Cambic Latosol and Epieutrophic Cambisol, respectively. The soil variables (related to the fertility and texture) and the soil water regime (drainage) were probably the principal factors determining the spatial distribution patterns of tree species in the forest.
Development of electronic music in Ukraine: emergence of a research methodology
Authors: Zagaykevych Alla , Zavada Ivan
Published: July 2007

In this article the authors present an overview of the current situation in Ukraine, with regards to the question of analytical terminology applied to new methods of creation in electronic music composition. The article establishes the differences and the similarities between the analyses of instrumental and electronic music structures, while considering the role of technology in the creation of new electronic music works. This paper also establishes a link between the origin of current analytical processes and electronic music practice in Ukraine, taking into account the function of a given terminology and its characteristic elements relating to a local geographical and cultural context. The authors underline the importance of integrating new music forms in academic circles and discuss external influences in the development of new musical systems. This is demonstrated by exposing selected musical materials, which can be considered representative of the creative and theoretical processes found in the field of electronic music in Ukraine.
Reading in two writing systems: Accommodation and assimilation of the brain's reading network
Authors: PERFETTI CHARLES A. , LIU YING , FIEZ JULIE , NELSON JESSICA , BOLGER DONALD J. , TAN LI-HAI
Published: July 2007

Bilingual reading can require more than knowing two languages. Learners must acquire also the writing conventions of their second language, which can differ in its deep mapping principles (writing system) and its visual configurations (script). We review ERP (event-related potential) and fMRI studies of both Chinese–English bilingualism and Chinese second language learning that bear on the system accommodation hypothesis: the neural networks acquired for one system must be modified to accommodate the demands of a new system. ERP bilingual studies demonstrate temporal indicators of the brain's experience with L1 and L2 and with the frequency of encounters of words in L2. ERP learning studies show that early visual processing differences between L1 and L2 diminish during a second term of study. fMRI studies of learning converge in finding that learners recruit bilateral occipital-temporal and also middle frontal areas when reading Chinese, similar to the pattern of native speakers and different from alphabetic reading. The evidence suggests an asymmetry: alphabetic readers have a neural network that accommodates the demands of Chinese by recruiting neural structures less needed for alphabetic reading. Chinese readers have a neural network that partly assimilates English into the Chinese system, especially in the visual stages of word identification.
Neural plasticity in speech acquisition and learning
Authors: ZHANG YANG , WANG YUE
Published: July 2007

Neural plasticity in speech acquisition and learning is concerned with the timeline trajectory and the mechanisms of experience-driven changes in the neural circuits that support or disrupt linguistic function. In this selective review, we discuss the role of phonetic learning in language acquisition, the “critical period” of learning, the agents of neural plasticity, and the distinctiveness of linguistic systems in the brain. In particular, we argue for the necessity to look at brain–behavior connections using modern brain imaging techniques, seek explanations based on measures of neural sensitivity, neural efficiency, neural specificity and neural connectivity at the cortical level, and point out some key factors that may facilitate or limit second language learning. We conclude by highlighting the theoretical and practical issues for future studies and suggest ways to optimize language learning and treatment.
Flavonoid content in seeds of guar germplasm using HPLC
Authors: Wang M. L. , Morris J. B.
Published: July 2007

Legume flavonoids have received considerable attention due to their beneficial effects on human health. Flavonoid content in the seeds of 36 germplasm accessions of guar [Cyamopsis tetragonoloba(L.) Taub.] was quantified by high-performance liquid chromatography (HPLC). On a per 100 g basis, the seed contained, on average, 1.114 mg (0–2.355) daidzein, 0.700 mg (0–1.685) genistein, 0.553 mg (0–1.250) quercetin and 14.460 mg (10.70–19.82) kaempferol. A significant positive correlation was observed between the content of daidzein and genistein; however, significant negative correlations existed between the content of kaempferol and daidzein and of kaempferol and genistein. Compared to soybean seeds, guar seeds contained very low amounts of daidzein and genistein, but a high amount of kaempferol. The information about the levels of flavonoids in guar seeds will be useful to breeding programmes for improving guar seed quality. Furthermore, the high kaempferol content of guar seeds may expand its nutraceutical and pharmaceutical utilization.
An assessment of grower perceptions and factors influencing adoption of IPM in commercial cranberry production
Authors: Blake G. , Sandler H.A. , Coli W. , Pober D.M. , Coggins C.
Published: July 2007

A survey was developed and distributed to the Massachusetts cranberry grower community in 1999 to identify biological, educational, social and political barriers to the adoption of available integrated pest management (IPM) practices. The response rate for the 450 growers who received the survey was 54%. Approximately 80% of respondents claimed to practice IPM frequently and 16% identified themselves as occasional practitioners. Most growers practiced IPM because they agreed with IPM philosophy (80%) and believed it had environmental benefits (73%). Ninety-two percent agreed that more IPM-related research and education programs would encourage them to adopt practices they are not currently using. A significant percentage of respondents used multiple IPM component practices, with practices involving monitoring and detection of pests along with judicious use of pesticides being most common. Factor analysis was used to condense 104 potential responses to 22 factors, which were then used as predictors with six demographic variables (IPM adoption, education level, age, experience, farm size and work status). Demographic factors influenced a grower's tendency to incorporate IPM into routine farm activities. Full-time, highly experienced growers in charge of large operations tended frequently to use more IPM practices than less experienced growers who worked part-time and managed smaller farms. A large proportion of respondents agreed that IPM can reduce pesticide residues in food (92%) and the environment (96%), and can help to preserve beneficial insects (96%). Although many growers held the perception that IPM can pose measurable economic risk (and subsequently act as a barrier to adoption), growers appeared to feel less strongly about the economic benefits than potential environmental ones.
Testing a complete-diet model for estimating the land resource requirements of food consumption and agricultural carrying capacity: The New York State example
Authors: Peters Christian J. , Wilkins Jennifer L. , Fick Gary W.
Published: July 2007

Agriculture faces a multitude of challenges in the 21st century, and new tools are needed to help determine how it should respond. Among these challenges is a need to reconcile how human food consumption patterns should change to both improve human nutrition and reduce agriculture's environmental footprint. A complete-diet framework is needed for better understanding how diet influences demand for a fundamental agricultural resource, land. We tested such a model, measuring the impact of fat and meat consumption on the land requirements of food production in New York State (NYS). Analysis was confined to this geographic area to simplify the modeling procedure and to examine the state's ability to reduce environmental impact by supplying food locally. Per capita land resource requirements were calculated with a spreadsheet model for 42 diets ranging from 0 to 381 g d−1 (0 to 12 oz d−1) of meat and eggs and 20 to 45% total calories from fat. Many of these diets meet national dietary recommendations. The potential human carrying capacity of the NYS land base was then derived, based on recent estimates of available agricultural land. A nearly fivefold difference (0.18–0.86 ha) in per capita land requirements was observed across the diets. Increasing meat in the diet increased per capita land requirements, while increasing total dietary fat increased the land requirements of low meat diets but reduced the land needed for high meat diets. Higher meat diets used a larger share of the available cropland suited only to pasture and perennial crops. Thus, only a threefold difference was observed for the potential number of people fed from the NYS land base (2.0–6.2 million). In addition, some high-fat vegetarian diets supported fewer people than lower fat diets containing 63–127 g d−1 of meat (approximately one- to two-thirds of the national average per capita consumption in the US). These results support the assertion that diet should be considered in its entirety when assessing environmental impact. To more completely understand how diet influences land requirements and potential carrying capacity, this model should be applied across a larger geographic area that encompasses a wider variety of climates and soil resources. To better understand the ability of a local region to supply more of its own food, the model should be moved into a geospatial framework.
Preface
Authors: Doran John W.
Published: July 2007

Renewable Agriculture and Food Systemsis a multi-disciplinary journal which focuses on the science that underpins economically environmentally and socially sustainable approaches to agriculture and food production. The journal publishes original research and review articles on the economic, ecological and environmental impacts of agriculture; the effective use of renewable resources and biodiversity in agro-ecosystems; and the technological and sociological implications of sustainable food systems.It also contains an open discussion Forum, which presents lively discussions on new and provocative topics.However, the opinions of the Forum and responses are solely those of the authors and do not necessarily reflect the opinions ofRenewable Agriculture and Food Systemsor Cambridge University Press.
Monoclonal antibodies which identify carbohydrate‐defined MHC Class I epitopes
Authors: O'NEILL HELEN C.
Published: July 2007

Eleven different monoclonal antibodies specific for H‐2K‐ and H‐2D‐encoded Class I molecules have been screened to determine Class I epitopes dependent on both carbohydrate and protein structures. Monoclonal antibodies have been identified which bind to carbohydrate‐defined antigens encoded by both the H‐2K and H‐2D gene regions. Sensitivity to glycosidases versus pronase has been used to classify antigens both expressed as cell surface molecules and when prepared as detergent solubilized antigen. Several simple sugars have also been found to act as inhibitors of antibodies which bind to carbohydrate‐defined sites. The genetic control of carbohydrate antigen expression by H‐2K‐ and H‐2D‐linked genes has been verified since a specific antibody does not bind to H‐2Kb or H‐2Db molecules encoded by several mutant strains of mice containing single amino acid substitutions in their protein product. All of these data are consistent with Class I antigenic structures being encoded in carbohydrate as well as protein moieties.
Human IgE‐binding synthetic peptides of bovine β‐lactoglobulin and α‐lactalbumin. In vitro cross‐reactivity of the allergens
Authors: ADAMS S. L. , BARNETT D. , WALSH B. J. , PEARCE R. J. , HILL D. J. , HOWDEN M. E. H.
Published: July 2007

The allergenicity of cow's milk whey proteins, purified by high performance liquid chromatography (HPLC), was examined by the radio‐allergosorbent test (RAST) against the sera of children immediately hypersensitive to milk. β‐lactoglobulin and α‐lactalbumin bound specific IgE in the sera of 63% and 75% of these patients respectively. These allergens were tested for cross reactivity with each other by RAST inhibition. Both inhibited the binding of IgE, in the sera of allergic patients, to the other protein. Two possible determinant peptides, one from β‐lactoglobulin and one from α‐lactalbumin, were selected by computer prediction of antigenic sites and synthesized by the fluorenylmethoxycarbonyl (FMOC)‐polyamide method. The peptides were adsorbed to nitrocellulose discs and used in further RAST studies with sera from the allergic children. Both peptides bound specific IgE in the RAST assay.
Depression of cell‐mediated immunity in plasmacytoma‐bearing mice
Authors: RUSZALA‐MALLON VERONICA , SILVA JILLIAN , LUMANGLAS ARACELI L. , DURR FREDERICK E. , WANG BOSCO SHANG
Published: July 2007

Previous reports have documented that mice bearing plasmacytomas (PC) are suppressed in their ability to mount a primary antibody response, whereas cellular immunity appears to be normal. Studies presented here provide evidence that T cell responsiveness is also depressed in BALB/c mice bearing the Lieberman plasmacytoma (Lpc‐1). For instance, splenocytes from mice bearing large tumours were impaired in their in vitro ability to respond to the T cell mitogen, mount an appropriate alloreactive cytolytic T lymphocyte response, and produce interleukin‐2 (IL‐2). A population of suppressor cells was detected in the spleens 7 days after tumour implantation as evidenced by their ability to prevent normal splenocytes not only from responding to antigens in mixed lymphocyte culture, but also from producing IL‐2. A similar inhibitory effect was observed with culture supernatants of these cells, indicating the existence of a soluble suppressive factor. Therefore, the present study demonstrates that cellular immune responses are impaired in mice bearing Lpc‐1 tumours and that this effect may be due to the generation of suppressor cells and/or a suppressive factor.
The induction of plasma leakage in skin by histamine, bradykinin, activated complement, platelet‐activating factor and serotonin
Authors: COLDITZ I. G.
Published: July 2007

Vascular leakage of [125I]‐human serum albumin into the skin of sheep was measured in response to intradermal injection of histamine, bradykinin, zymosan‐activated plasma (ZAP), platelet‐activating factor (PAF) and serotonin. Potency of the mediators was PAF > ZAP > bradykinin ∼ histamine > serotonin. Maximal leakage occurred in the first 10 min following injection of bradykinin, histamine and PAF, and for histamine and bradykinin had effectively ceased by 40 min. In contrast, ZAP and serotonin induced relatively constant plasma leakage over the first 40 min following their intradermal injection. Prostaglandins E1 and E2 enhanced plasma leakage induced by histamine and bradykinin thus confirming the applicability of the two‐mediator hypothesis of vascular leakage to permeability responses in skin of sheep.
Interleukin‐2 and phytohaemagglutinin stimulate proliferation of tunicate cells
Authors: RAFTOS DAVID A. , DAN STILLMAN L. , COOPER EDWIN L.
Published: July 2007

Profilerative responses of cells in tunicate pharyngeal explants to human interleukins and mitogenic lectins were tested. Increased tritiated‐thymidine ([3H]‐TdR) uptake was detected among pharyngeal cells incubated with recombinant human interleukin‐2 (IL‐2), and phytohaemagglutinin‐P (PHA‐P). Responses to IL‐2 were dose‐dependent and affected lymphocyte‐like cells. Enhanced proliferation was stimulated by IL‐2 in the absence of co‐stimulants and was not synergized by co‐incubation with human interleukin‐l (IL‐1) or PHA‐P. Anti‐IL‐2 polyclonal antibody inhibited the stimulatory activity of recombinant human interleukin‐2 (rhIL‐2). Of three lectins tested (concanavalin‐A [Con‐A]. pokeweed mitogen [PWM] and PHA‐P), only PHA‐P proved to be mitogenic. Con‐A and PWM did not significantly increase proliferative activity even though both lectins were capable of binding pharyngeal cells as revealed by flow cytometry and fluorescence microscopy. Similarly, human IL‐I had no effect on [3H]‐TdR uptake either alone or in combination with IL‐2 and PHA‐P. These data suggest that the functions of some interleukin‐like cytokines have been conserved during evolution.
Preferential binding ofChlamydia trachomatisto subsets of human lymphocytes and induction of interleukin‐6 and interferon‐gamma
Authors: FITZPATRICK D. R. , WIE J. , WEBB D. , BONFIGLIOLI R. , GARDNER I. D. , MATHEWS J. D. , BIELEFELDT‐OHMANN H.
Published: July 2007

The interactions betweenChlamydia trachumatisand human blood mononuclear leukocytes were studied using flow cytometry. Immunofluorescence, electron microscopy and cytokine assays. Under serum‐free conditions, elementary bodies (EB) ofC. trachomatiswere found to bind to human T lymphocytes as well as to B cells and monocytes/macrophages (Mφ). For all cell types the binding was saturable. rapid, temperature‐independent and independent of the chlamydia‐specific serological status of the donor. Similar proportions of T and B cells bound EB at similar levels. In the T cell population, proportionally less CD8+cells bound EB. Whereas Mφ phagocytosed and destroyed the bound micro‐organisms for lymphocytes, theChlamydiaremained at the surface, adherent to morphologically featureless membrane areas and showed no evidence of uptake even after long periods at 37°C. Host molecules modulated these basic binding patterns: a heat‐stable serum factor inhibited EB binding to T cells and a heat‐labile serum factor enhanced binding to B cells. Stimulation withC. trachomatisEB rapidly elicited cytokine production by lymphocytes including interleukin‐6 from B cells and interferon‐gamma (IFN‐γ) from T and/or nonT/nonB cells. The responses were irrespective of the serological status of the donor. The findings suggest thatC. trachomati‐leucocyteinteractions may differ from the interactions of other bacteria and human leucocytes. The possible relationship between leucocyte‐binding, cytokine induction, and the pathognomonic development of lymphoid follicles during mucosalC. trachomatisinfections is discussed.
Dextran sulfate induces changes in the free intracellular calcium ion concentration of a subpopulation of immature thymocytes
Authors: WESTON SUSAN A. , TELLAM ROSS L. , PARISH CHRISTOPHER R.
Published: July 2007

Previous studies have shown that certain sulfated polysaccharides, such as dextran Sulfate (DxS), can induce a rapid and sustained increase in the free intracellular calcium ion concentration ([Ca2+]i) of thymocytes, whereas they cannot induce a change in the [Ca2+]i of peripheral lymphocytes. This study examined this phenomenon in more detail and clearly demonstrated that only immature thymocytes can respond to DxS. Cortisone‐resistant thymocytes failed to exhibit an increase in [Ca2+]i when exposed to DxS. Furthermore, analysis of [Ca2+]i changes at the single cell level using a flow cytometer demonstrated that only a subpopulation of immature thymocytes responded to DxS. Additional flow cytometry studies revealed that DxS and Con‐A induce a [Ca2+], response in different subpopulations of thymocytes, approximately 3O% of thymocytes responding to Con‐A and 15–20% to DxS. Thus, responsiveness to Con‐A and DxS. in terms of increases in [Ca2±]i, may represent a novel marker for two different thymocyte subpopulations. Such metabolic markers could be used to complement the conventional serological methods currently employed to define stages in thymocyte differentiation.
Regulation of human lymphocyte proliferation by a tumour cell‐derived DNA fraction
Authors: ABOLHASSANI MOHSEN , TILLOTSON JOANNE K. , CHANG JEAN , CHIAO J.W.
Published: July 2007

A suppressor activity was isolated and partially purified from culture supernatant of human myeloid leukaemic cell line HL‐60 by ion‐exchange chromatography. HPLC and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). This activity was capable of suppressing proliferation of mitogen‐stimulated normal human lymphocytes in a dose‐dependent manner. The suppressor activity was identified as DNA by its typical absorbance at 260 nm, and by its susceptibility to DNase digestion. The DNA with suppressive activity was found to be double‐stranded with the molecular weight range between 0.6 and 1.5 kb. This DNA material did not have cytotoxic activity and did not alter intcrleukin‐2 receptor expression. Cell cycle analysis has suggested that DNA molecules could interact with lymphocytes to arrest the stimulated lymphocytes in the G1 phase, apparently preventing the cells from entering into the proliferating S phase.
Phenotype and activation of milk‐derived and peripheral blood lymphocytes from normal and coeliac subjects
Authors: GIBSON C. E. , EGLINTON B. A. , PENTTILA I. A. , CUMMINS A. G.
Published: July 2007

The phenotype of milk‐derived and peripheral blood lymphocytes from normal and coeliac subjects was assessed for CD3. αβ‐TcR (T cell receptor). γδ‐TcR, CD4, CD8, HML‐I (human mucosal lymphocyte) determinants, and activation was measured by interleukin‐2 receptor (1L‐2R) expression. Milk cells from normal and coeliac subjects were analysed by manual immunofluorescence and milk and blood cells from normal subjects were analysed by flow cytometry. Milk cells from two coeliac subjects were tested for proliferation to gluten antigen. The CD4:CD8 ratio of milk lymphocytes from both normal and coeliac subjects was similar (0.78‐1.1), but lower than that present in blood (1.5‐2.1). The IL‐2R expression of milk lymphocytes from both coeliac and normal subjects was increased by 3–6 times compared with peripheral blood cells. For example, IL‐2R was present on 27.3% of milk CD3+ lymphocytes and on 8.0% of blood CD3+ lymphocytes from normal subjects. γδ‐and HML‐I+ T cells were increased 4.2‐fold and 12‐fold respectively compared with blood lymphocytes. Milk cells from coeliac subjects showed specific proliferation to gluten but not to soya bean antigen. We conclude that milk cells have a ‘mucosal’ phenotype, with increased γδ‐TCR. CD8+ and HML‐I+ T cells, and have an increased proportion of activated cells. Milk cells from celiac subjects have no ‘toxic’ phenotype, but show functional reactivity by specific proliferation to gluten antigen.
Participation of cytoplasmic organelles in E‐rosette formation
Authors: ISHIJIMA SANAE A. , ASAKURA HIDEKI , SUZUTA TATSUO
Published: July 2007

To elucidate the mechanism of E‐rosctte formation between T cells and sheep red blood cells(SRBC), the effect of various agents affecting the function of cytoplasmic structures(microtubules and microfilaments) and organdies (mitochondria and rough endoplasmic reticulum) was investigated. E‐rosette formation was greatly inhibited by agents that block cither the energy producing system (KCN and NaN3) or the integration of microfilaments (cytochalasin B. dihydrocytochalasin B and cytochalasin D). On the other hand, there was little or no suppression by either inhibitors of protein synthesis (cycloheximide and puromycin). agents that block the polymerization of microtubules (colchicine. podophyllotoxin and vinblastine), or chemicals disconnecting surface membrane proteins from the intracellular structural proteins (chlorpromazine, dibucaine. hydrocortisone. and propranolol). The calcium ionophore A23187, which transports Ca2 into the cytosol, inhibited the F‐rosette formation in the presence of Ca2+, but not in its absence. From these results, we concluded that new synthesis of ATP and the structural integration of microfilaments are indispensable for the E‐rosette formation, which is triggered by an interaction between the ligand (TIITS) and its corresponding receptor (CD2). A certain level of intracellular Ca2+ is also involved in the E‐rosette formation.
Preparation and characterization of a chimeric CD 19 monoclonal antibody
Authors: ZOLA H. , MACARDLE P. J. , BRADFORD T. , WEEDON H. , YASU H. , KUROSAWA Y.
Published: July 2007

FMC63 is an IgG2a mouse monoclonal antibody belonging to the CD19 cluster, CD19 antibodies react with a 95kDa protein expressed by cells of the B lymphocyte lineage, from pre‐B cells to mature B lymphocytes. CD19 antibodies have been suggested as candidates for immunological attack on leukaemic and lymphoma cells of the B lineage because the antigen is restricted to the B lineage, With the potential use of FMC63 in immunotherapy in mind, we have produced a mouse‐human chimera in which the genes coding for the VDJ region of the heavy chain and the VJ region of the light chain derive from the FMC63 mouse hybridoma, while the C region genes code for human IgGl. The genes have been transfected back into a mouse myeloma line, which secretes low levels of immunoglobulin. (Ig). This Ig was purified and biotinylated in order to determine the specificity of the antibody. The chimeric antibody has a read ion profile concordant with the original FMC63 antibody, but has the properties of a human IgG1, including the ability to fix human complement. However, the antibody is not cytotoxic in vitro in the presence of complement or cells capable of mediating antibody‐dependent cellular cytotoxicity. Possible reasons for this and ways of using the antibody are discussed.
Arachidonic acid metabolites in normal and autoimmune mice do not influence lymphocyte‐high endothelial venule interactions
Authors: MANOLIOS N. , BAKIERA B. , GECZY C. L. , SCHRIEBER L.
Published: July 2007

In peripheral lymphoid organs the number of lymphocytes and the proportion of functional lymphocyte subsets are regulated by multiple factors including the control of lymphocyte migration by selective lymphocyte‐high endothelial venule (HEV) interactions. In this study, prostaglandin E2 (PGE2) levels from normal and autoimmune mouse lymph node cells were measured. The contribution of eicosanoids to lymphocyte‐HEV interactions in normal (CBA/T6) and autoimmune (MRL/n) mice was examined. There was no association between PGE2 production in normal or autoimmune mice and the age of onset of disease activity in the latter strains. Arachidonic acid metabolites, in particular PGE2 and leukotriene B4 (LTB4), did not have any effects on lymphocyte‐HEV binding. Likewise, lymphocytes treated in vivo and/or in vitro with arachidonic acid metabolite inhibitors (acetyl salicylic acid, indomethacin, BW755C) did not alter lymphocyte‐HEV binding interactions in both normal and autoimmune mice. No clinical significance could be attributed to lymph node PGE2 production and the age of onset of autoimmune disease. In summary, these findings cast doubt on the role of arachidonic acid metabolites in lymphocyte‐HEV binding interactions.
Chronic osteomyelitis as a consequence of systemic Candida albicans infection
Authors: ASHMAN R. B. , PAPADIMITRIOU J. M.
Published: July 2007

The yeast Candida albicans is a recognized, though uncommon, cause of osteomyelitis in humans. In a mouse model of systemic candidiasis, osteomyelitis has been found to occur in the vicinity of the inner ear, and to persist for at least 6 months after the initial infection.
Monoclonal antibodies to Kunjin and Kokobera viruses
Authors: HALL ROY A. , BURGESS GRAHAM W. , KAY BRIAN H. , CLANCY PAULA
Published: July 2007

Five monoclonal antibodies (MoAb) were produced to the envelope (E) protein of Kunjin (KUN) virus. Three of these were specific for the KUN/West Nile complex, and two reacted with epitopes that were common to the flavivirus family. These MoAb defined at least four distinct epitopes on the E protein of KUN virus. Eight MoAb were also produced to unidentified proteins of Kokobera (KOK) virus. Seven were specific for KOK, while the remaining antibody cross‐reacted with Stratford virus and an unregistered flavivirus CS946. The application of these MoAb to arboviral surveillance is discussed.
Pattern of the action of a suppressor factor produced by a human macrophage‐like cell line, U937
Authors: OHNISHI KAZUKO , FUJIWARA HIROSHI , TSUYUGUCHI IZUO , KISHIMOTO SUSUMU
Published: July 2007

A U937 suppressor factor (U937SF) was purified from crude supernatant by sequential chromatography using fast protein liquid chromatography. The molecular weight and isoelectric point of U937SF were 69 kDa and 4.5, respectively. The U937SF preparation inhibited the proliferative response in human PBMC stimulated with an antigen tuberculin purified protein derivative, tetanus toxoid) or a mitogen (phytohaemagglutinin concanavalin‐A). U937SF depressed both interleukin‐2 (IL‐2) production and IL‐2 receptor (CD25) expression in peripheral blood mononuclear cells (PBMC) stimulated with an antigen but not with a mitogen. Anti‐CD3 monoclonal antibody‐induced responses including a proliferative response, IL‐2 production and CD25 expression were suppressed by U937SF. In contrast, U937SF did not affect monocyte functions such as antigen processing and IL‐1 production. Neither did it modulate the expression of T cell receptor (TCR) or CD3 molecules on the surface of lymphocytes. Moreover it did not inhibit CD25 expression in PBMC stimulated with phorbol myristate acetate plus A23187. These results suggest that U937SF prevents both IL‐2 production and CD25 expression in lymphocytes activated through the TCR/CD3, but not through the other receptors or molecules. In addition, U937SF does not block the early activation events following TCR‐mediated stimulation, nor affect the pre‐TCR activation steps.
A role for tumour necrosis factor‐α in the human mixed lymphocyte culture reaction
Authors: MATTHEWS S. J. , SULLIVAN J. S.
Published: July 2007

The possible role and influence of tumour necrosis factor‐α (TNF‐α) in the human mixed lymphocyte culture (MLC) reaction was investigated. Polyclonal rabbit sera to recombinant human‐TNF‐α (rhTNF‐α) consistently inhibited the MLC, and this could be reversed by simultaneous addition of rhTNF‐α to the culture medium. Under optimal cell culture conditions, the exogenous addition of 1000 U/mL of rhTNF‐α had a variable but generally small enhancing effect on the MLC reaction. Additional studies have clearly highlighted the importance of MLC assay conditions in influencing the effect of exogenous rbTNF‐α. Enhancement of the MLC reaction was only consistently observed under suboptimal cell culture conditions. While the present study clearly supports an important role for TNF in controlling the proliferative response in the human MLC reaction it also highlights the influence of in vitro tissue culture conditions in determining the effect of exogenous TNF‐α in this assay.
Western blot analysis of antibody responses to influenza virion proteins
Authors: QIU DIWEN , TANNOCK GREGORY A. , BARRY RICHARD D. , JACKSON DAVID C.
Published: July 2007

An immunoblotting procedure was developed to detect antibody responses in mice and humans to influenza virion proteins. The technique was capable of detecting 1.5 μg of haemagglutinin (HA) on nitrocellulose strips at a 1: 5000 dilution of a mouse serum with an initial haemagglutination inhibition titre of 20. The effects of the use of the blocking agent Tween‐20 on virion proteins were also studied. The commonly used concentration of 0.05% (v/v) Tween‐20, when included in blocking and incubation buffers, greatly reduced the amount of detectable matrix protein but caused no detectable loss of HA and neuraminidase/nucleoprotein proteins. If virion proteins were separated by polyacrylamide gel electrophoresis under reducing conditions, antibody bound to HA2 more strongly than to HA1. Under non‐reducing conditions, more antibody bound to the uncleaved HA protein than to other proteins. IgG1 and IgG2a antibody responses in mice to each protein were stronger than IgG2b and IgG3 responses.
The diversity of retroviral diseases of the immune system
Authors: O'NEILL HELEN C.
Published: July 2007

Retroviruses have been implicated as causative agents for a range of diseases including neoplasia, autoimmunity and immunosuppression. No two retroviruses carry the same complement of genes and for this reason it is not surprising that they induce a variety of different disease states. One common element in retroviral evolution has been the need to avoid immune recognition in order to persist within the host. A comparative approach, looking at various persistent retroviruses, has been used to pin‐point the types of genetic adaptations adopted by retroviruses to remain hidden, often within the T cell compartment. Most of these retroviruses are T‐cell‐tropic and the diseases which they induce usually reflect the effect of the retrovirus on normal lymphocyte function.
Restimulated memory Tc cells have a higher apparent avidity of interaction with targets than primary virusimmune Tc cells as indicated by anti‐CD 8 blocking
Authors: HILL ANN B. , BLANDEN ROBERT V. , PARRISH COLIN R. , MÜLLBACHER ARNO
Published: July 2007

Previous experiments have shown that whereas a secondary in vitro Kunjin‐immune cytotoxic T (Tc) cell population lysed equally well targets infected with either native flavivirus or a recombinant vaccinia virus expressing the immunodominant determinant, primary in vivo Kunjinimmune Tc cells were able to lyse only the recombinant vaccinia virus‐infected targets. Using CD8 blockade to assess the avidity of T cell‐target interaction, recombinant‐infected targets express antigen more efficiently than native flavivirus infected targets and secondary in vitro Kunjin‐immune Tc cells have a higher avidity for targets than do primary in vivo Kunjin‐immune Tc cells. Secondary in vivo influenza‐immune Tc cells are also of higher avidity than primary in vivo influenza‐immune Tc cells. Thus, a restimulated memory Tc cell population interacts with targets with greater avidity than does a recently activated naive population.
Effect of sodium stibogluconate and pentamidine on in vitro multiplication of Leishmania donovani in peritoneal macrophages from infected and drug‐treated BALB/c mice
Authors: SODHI S. , KAUR S. , MAHAJAN R. C. , GANGULY N. K. , MALLA N.
Published: July 2007

The in vitro antileishmanial activity of sodium stibogluconate (SSG) and pentamidine in peritoneal macrophages from three different groups of animals (i.e. normal, Leishmania donovani infected and drug‐treated BALB/c mice) is reported. Peritoneal macrophages were extracted from all these animals and infected in vitro with L. donovani promastigotes. After 24 h, the infected macrophages (with amastigotes) were exposed to various concentrations of SSG (10–90 μg/mL) and pentamidine (0.1–5.0 μg/mL). The in vitro infection could he cured readily with 80 μg/mL of SSG and 4 μg/mL of pentamidine in macrophages from normal animals. But even higher dosages of these drugs added in vitro could not reduce the amastigote loads in macrophages from infected animals. In contrast, incubation in vitro of infected macrophages with very low dosages of these drugs (40 μg/mL of SSG and 1.0μ/mL of pentamidine) could eliminate the parasites present within macrophages obtained from drug‐treated animals. This was probably because the macrophages from drug‐treated animals tackled the parasites themselves by their microbicidal mechanisms and the in vitro infection was tackled by the drug in vitro. This implies that a well‐developed specific immunity in leishmaniasis helps in the antileishmanial activity of these drugs.
Proliferation of the BCL1 B cell lymphoma induced by IL‐4 and IL‐5 is dependent on IL‐6 and GM‐CSF
Authors: NI KEPING , O'NEILL HELEN C.
Published: July 2007

Lymphokine requirements for the in vitro proliferation of the spleen‐dependent B cell lymphoma BCL1 have been analysed. Cells were found to respond by proliferation to added recombinant (r) interleukin‐4 (IL‐4), r‐IL‐5 and recombinant granulocyte‐macrophage colony‐stimulating factor (r‐GM‐CSF). Inhibition by antibodies specific for each of these lymphokines has confirmed growth factor‐dependent growth. Anti‐GM‐CSF has, however, been found to inhibit the proliferation of BCL1 cells induced by r‐IL‐4 and r‐IL‐5, as well as r‐GM‐CSF, suggesting that BCLI cells may express receptors for GM‐CSF and that GM‐CSF may be able to act synergistically with IL‐4 and IL‐5 in promoting cell proliferation. Anti‐IL‐6 antibody was also found to be a very effective inhibitor of BCL1 proliferation induced by either IL‐4 or IL‐5 but not by GM‐CSF. Added IL‐6 did not stimulate BCL1 proliferation, suggesting that endogenous IL‐6 may regulate the autocrine growth of BCL1 cells. BCL1 cell proliferation in vitro appears to be regulated by interactions between multiple growth factors.