bluuebunny/crossref_metadata_2025_split huggingface dataset:
The mechanism of bone marrow‐derived (B) lymphocyte activation. I. Early events in antigen‐induced triggering in the presence of polymerized flagellin
Authors: Schrader J. W. 
Published: February 2007

AbstractThe primary in vitro response to fowl IgG (FGG) of spleen cells from congenitally athymic (nu/nu) mice was used as a model of antigen‐induced bone marrow‐derived (B) lymphocyte activation. Functional evidence was presented that deaggregated FGG (De‐FGG) bound rapidly to B lymphocytes at 0 °C, an antibody‐forming cell (AFC) response to FGG occurring if the spleen cells, after washing off of unbound FGG, were subsequently cultured in the presence of polymerized flagellin (POL). This supported the concept that antigen can induce B cell triggering without being presented in a multivalent form.Conversely, De‐FGG could not be demonstrated by functional studies to bind to spleen cell suspensions at 37 °C so as to initiate subsequent triggering in the presence of POL. In fact, FGG which had bound at 0 °C became ineffective in B cell triggering if the spleen cells were briefly incubated at 37 °C before being washed and cultured with POL. However, if cells were incubated for 60 min at 37 °C with FGG in the presence of POL, washing of the cells did not prevent a significant response in the absence of further additions of FGG. When cells that had been incubated for 60 min at 37 °C with FGG and POL were treated with trypsin and were cultured without the addition of further POL or FGG, a significant anti‐FGG antibody‐forming cell response still occurred. This implied that activation of some B cells had proceeded within 60 min to a stage independent of further extracellular antigen. It was shown that this initial activation proceeded independent of the presence of fetal calf serum.An additional observation was that when cells that had been incubated at 37 °C with FGG plus POL were treated with trypsin after they had been washed, the subsequent anti‐FGG response was reduced compared to that of cells that had merely been washed. Possible mechanisms for this effect are considered.
The mechanism of bone marrow‐derived (B) lymphocyte activation. II. A “second signal” for antigen‐specific activation provided by flagellin and lipopolysaccharide
Authors: Schrader J. W. 
Published: February 2007

AbstractEvidence is presented that the activity of polymerized flagellin (POL) in allowing spleen cells from congenitally athymic (nu/nu) mice to respond in vitro to the thymus‐dependent antigen fowl IgG (FGG), is due to an intrinsic property of the POL molecule, rather than to some minor contamination of the preparation by lipopolysaccharide (LPS). While LPS prepared from the same Salmonella strain as was the POL was shown to be active in the present system, the potency of the LPS was not sufficient to account simply for the activity of the POL preparation in the light of its possible endotoxin content. Additionally, the activity of the POL was shown to be susceptible to treatment by the proteolytic enzymes, trypsin and pepsin. Thus, it is shown that two substances, one a protein, the other a LPS, share the property of allowing bone marrow‐derived (B) cells to be triggered by antigen in the absence of thymus‐derived (T) cells. A basis for the common action of LPS and the protein POL was sought in their shared polymeric nature. However, the monomeric form of flagellin, even when oxidized so that it did not repolymerize under stringent conditions, was still active, suggesting that the situation is more complex.
Immunological responses of guinea pigs to a synthetic autoantigen of brain
Authors: Lennon Vanda A. , Carnegie P. R. 
Published: February 2007

AbstractA synthetic peptide, Ser‐Arg‐Phe‐Ser‐Trp‐Gly‐Ala‐Glu‐Gly‐Gln‐Arg, of identical sequence to residues 112 to 122 of the basic protein of human myelin was active in guinea pigs in inducing experimental autoimmune encephalomyelitis. This peptide did not induce a humoral immune response, but a cellular immune response was obtained, as judged by transformation of splenic lymphocytes when these were cultured with the human encephalitogenic protein, and by demonstration of macrophage inhibitory factor when peritoneal exudate cells were incubated with the protein.
T cell suppression in vitro. I. Role in regulation of antibody responses
Authors: Feldmann Marc 
Published: February 2007

AbstractSuppression of the antibody response by supraoptimal numbers of T helper cells was studied in vitro and found to have both a specific and a nonspecific component. Suppression did not depend on direct cell contract of T and B cells, as supernatants of activated T cells were just as inhibitory. Suppression by excess T cells (or T cell supernatant) was abrogated by the addition of macrophages. By using a tolerance induction protocol, it was shown that T cell supernatants induce partial tolerance in both T and B cells. This tolerance occurred in three different experimental settings – if adherent cells were physically removed by surface adherence, in the presence of anti‐macrophage serum, or in the presence of very high concentrations of T cell supernatant. All three conditions stress the importance of the interaction between T cell supernatants and macrophages.The nonspecific form of suppression was not analyzed in detail here, but was also shown to be partly abrogated by macrophages, suggesting that it may be analogous to antigenic competition, one model of which has recently been shown to be abolished by addition of macrophages. The results suggest the presence of homeostatic feedback loops, due to excess T cell function – T cell products suppress the function of T cells, preventing the induction of further helper cells, and also suppress B cells directly. The balance between T cell suppression and cooperation is affected by macrophage function.
An allotypic marker on chicken immunoglobulin M
Authors: Pink J. R. L. 
Published: February 2007

AbstractAn allotypic marker, present on IgM, but not IgG, molecules in sera from chickens of the inbred CA, CB and G‐B1 lines, is described. The marker, called “C‐Ml”, is absent in sera from birds of the WA and WB lines, and its segregation in (CB × WA)F2 birds is consistent with its inheritance as a single dominant factor. It can be detected in sera of normal (CA) one‐week‐old birds. The locus controlling this allotype marker is not sex‐linked, nor is it closely linked to the serum albumin, dominant white feather color, or B blood group and major histocompatibility loci.
The kinectics of proliferation and maturation of mitogen‐activated bone marrow‐derived lymphocytes
Authors: Melchers F. , Andersson J. 
Published: February 2007

AbstractThe B cell mitogens lipopolysaccharide (LPS), purified protein derivative of tuberculin (PPD) and fetal calf serum (FCS) all stimulate spleen cells from nude mice to increased DNA‐synthesis 14 to 16 h after the initiation of mitogenic stimulation. The three mitogens also induce the maturation of B cells to plaque‐forming cells (PFC). All three mitogens stimulate largely identical B cell populations. The extent to which B cells are stimulated to DNA synthesis and to the development of PFC varies from mitogen to mitogen.PFC arise by clonal growth through proliferation and maturation. A “hot pulse” of radioactive thymidine given between 0 and 20 h of stimulation has no effect on the development of PFC during subsequent mitogenic stimulation. Pulses given between 24 and 36 h after stimulation abolish the development of over 90 % of the PFC. The minimum pulse time required for maximum inhibition of the development of PFC during that time is 6 h. Beyond 36 h of stimulation by either of the three mitogens, PFC emerge rapidly. Between 60 and 72 h less than 10 % of all PFC emerging at 72 h are abolished by a “hot pulse”.The kinetics of the clonal development of PFC after mitogenic stimulation are compared to that of antigenic stimulation. The comparison suggests that B cells stimulated by antigen in the in vivo primary immune response culture system go through a longer period of proliferation than when they are stimulated by mitogen before maturation to PFC.
Papain‐resistant (f) and papain‐sensitive (g) subclasses of rabbit slgA. Allotypic specificities on different domains of the g subclass of α‐chains (αg)
Authors: Malek T. R. , Hanly W. Carey , Knight Katherine L. 
Published: February 2007

AbstractSecretory IgA (sIgA) from rabbits homozygous for the f71 and g75 allotypic specificities of the f and g subclasses, respectively, was digested into four fractions: sIgA, Fc2α, Fab2α and Fabα. The subclass and allotypic characteristics of each fraction were determined by quantitative radioprecipitation analyses. The f71 allotypic specificities were found predominantly in the undigested sIgA (with some in the Fabα fragment) and the g75 allotypic specificities were in the Fc2α and Fab2α fractions. Previous data from our laboratory indicated that the f72 and f73 sIgA allotypes of the g subclass are resistant to cleavage and that the g74 sIgA allotype of the g subclass is cleaved by papain. The present and previously reported data support the hypothesis that resistance or sensitivity of rabbit sIgA to papain digestion is a function of the subclass rather than the individual allotypic specificities.Quantitative radioprecipitation analyses of the Fc2α and Fab2α fragments showed that the “g” allotypic specificities are composed of multiple determinants, some of which reside on the Fd part of the α‐chain and some of which reside on the Fc part of the α‐chain. Anti‐allotype antisera have been prepared which are specific for the allotype determinant(s) present on each of the fragments. Of special interest is the ability to serologically distinguish the CH1 domain on the Fd fragment of a rabbit α‐chain.
Inhibition of lymphocyte proliferative responses by anti‐HL‐A alloantisera
Authors: Brochier J. , Roitt I. M. , Festenstein H. 
Published: February 2007

AbstractAnti‐HL‐A sera from women immunized by pregnancy, inhibit the proliferative response in mixed lymphocyte cultures. Inhibition is not necessarily related to the presence of lymphocyte HL‐A antigens corresponding to the cytotoxic antibodies demonstrable in these sera. Analysis of the results and appropriate absorption studies are indicative of other noncytotoxic inhibitory antibodies with non‐HL‐A specificity; the presence of antibodies directed against antigens on lymphocytes from male as distinct from female donors, and other as yet unidentified antigens is demonstrated. At low concentrations, these antibodies inactivate the stimulating cells; after suitable absorption of non‐HL‐A antibodies, cytotoxic anti‐HL‐A antibodies are seen to inhibit only stimulating cells carrying the relevant HL‐A antigens. At higher antiserum concentrations the responding cells are also inhibited; it is not clear, however, if anti‐HL‐A antibodies contribute to this effect. PPD‐induced transformation is also inhibited by non‐HL‐A antibodies, HL‐A antibodies being effective (if at all) only at high concentration. Inhibition is not mediated by inactivation of adherent cells. The mechanism of the inhibitions and the possible relationship between the strong MLR locus and the Ir gene product is discussed.
Inhibition of mitogenic stimulation of mouse lymphocytes by anti‐mouse immunoglobulin antibodies. I. Mode of action
Authors: Andersson J. , Bullock W. W. , Melchers F. 
Published: February 2007

AbstractAntibodies with specificities for mouse μ‐chains and mouse ϰ‐ and λ‐chains inhibit the stimulation of the major fraction of splenic lymphocytes from nude mice by lipopolysaccharide (LPS), by the purified protein derivative of tuberculin (PPD) and by fetal calf serum (FCS) to differentiate into immunoglobulin (Ig)‐secreting, plaque‐forming cells (PFC). Antibodies with specificities for mouse γ‐chains of with Ig‐unrelated specificities (anti‐ovalbumin, anti‐E. coli β‐galactosidase) do not elicit this inhibition. Bivalent pepsin (Fab')2 fragments mediate the same inhibition at the same concentrations, while monovalent papain Fab fragments of such anti‐Ig antibodies have a 100‐fold lower capacity to inhibit differentiation into PFC. Rabbit as well as chicken anti‐Ig antibodies are inhibitory; this indicates that the inhibition is not complement‐mediated. Cells stimulated for 6 h by LPS can no longer be inhibited by anti‐Ig antibodies from differentiating to PFC, a finding which indicates that changes take place in the mitogen‐stimulated cells which may involve surface‐bound Ig molecules. Inhibition can be abrogated, but only prior to the addition of mitogen to the cells, by proteolytic treatment of the cells or by dissociation of the anti‐Ig antibodies in excess medium with time from the cells.Inhibition of DNA synthesis by anti‐Ig antibodies in splenic lymphocytes is more complex and will be described in a subsequent publication.
IgD and IgM on the membrane of lymphoid cells in macroglobulinemia. Evidence for identity of membrane IgD and IgM antibody activity in a case with anti‐IgG receptors
Authors: Pernis B. , Brouet J. C. , Seligmann M. 
Published: February 2007

AbstractMonoclonal B lymphocyte populations from the bone marrow of seven cases of Waldenström's macroglobulinemia were studied for membrane IgD and IgM. In all cases lymphocytes with both classes on the membrane were found as well as cells with IgD or IgM only; the relative percentages of these three groups of lymphocytes were different in different cases. The IgM‐containing plasma cells always had membrane IgM and some of these also had IgD. Of particular interest was one patient whose macroglobulin had an anti‐IgG reactivity. The peripheral blood B lymphocytes of this patient had both membrane IgM and membrane IgD: it was possible to show, by capping with anti‐IgG or with aggregated IgG, that both classes of immunoglobulin receptors shared reactivity with human IgG.
Enhancement of the expression of histocompatibility antigens of mouse lymphoid cells by interferon in vitro
Authors: Lindahl Pernilla , Leary Patricia , Gresser I. 
Published: February 2007

AbstractThe expression of surface antigens of thymocytes and splenic lymphocytes was determined by quantitative absorption of alloantibodies. Mouse interferon preparations enhanced the expression of histocompatibility antigens of thymocytes from mice of different ages, but of splenic lymphocytes only from young mice. Interferon did not affect the expression of the theta antigen of thymocytes or splenic lymphocytes.
Nonspecific suppression of T lymphocyte responses in mice carrying progressively growing tumors
Authors: Kilburn D. G. , Smith J. B. , Gorczynski R. M. 
Published: February 2007

AbstractUnfractionated spleen cells from mice with four different types of progressively growing tumors were unable to show enhanced DNA or protein synthesis upon stimulation with phytohemagglutinin (PHA) in vitro. After separation by velocity sedimentation, or passage over an anti‐immunoglobulin column, cells were obtained which could respond to this mitogen. An auxiliary population of cells obtained by velocity sedimentation, sedimenting with the characteristics of activated B lymphocytes and sensitive to the cytotoxic effects of anti‐immunoglobulin serum and complement, could depress the response of normal spleen cells challenged with PHA. A role for this cell type in the tumor progression seen in the host animals is discussed.
T cell suppression of contact sensitivity in the mouse. III. The role of macrophages and the specific triggering of nonspecific suppression
Authors: Asherson G. L. , Zembala M. 
Published: February 2007

AbstractPassive transfer of contact sensitivity and suppression of contact sensitivity by lymph node cells is abolished by treatment with anti‐Θ serum and complement. In contrast, both these forms of passive transfer by peritoneal exudate cells resist treatment with anti‐Θ serum but are abolished by trypsin. This suggests that the cell responsible in the peritoneal exudate is a macrophage or other Θ‐negative cell.Peritoneal exudate cells can be armed for suppression by incubation in suppressor supernatant and a similar cell is probably responsible. Double transfer experiments show that suppressor lymph node cells produce factor(s) in vivo which inhibit “macrophage‐mediated transfers” of skin reactions.The specificity of the passive transfer of suppression by suppressor lymph node cells, suppressor peritoneal exudate cells, and peritoneal exudate cells armed for suppression was studied. All systems were specific in that the cells failed to suppress passive transfer of contact sensitivity to 4‐ethoxy‐methylene‐2‐phenyloxazolone (Ox) when the recipients were challenged with Ox. However, in the peritoneal exudate cell systems but not in the lymph node system, nonspecific suppression occurred when mice were challenged with a mixture of two antigens – picryl chloride corresponding to the suppressor cells, and Ox corresponding to the cells mediating passive transfer. The hypothesis is put forward that lymphocytes convey a factor to macrophages which enables them, in the presence of antigen, to suppress the passive transfer of contact sensitivity nonspecifically.
Carbon Nanotube Composite as Novel Platform for Microbial Biosensor
Authors: Kirgoz Ülkü A. , Timur Suna , Odaci Dilek , Pérez Briza , Alegret Salvador , Merkoçi Arben 
Published: February 2007

AbstractThe presented work includes the development of a microbial biosensor based on a carbon‐nanotube epoxy composite (CNTEC) platform used as supporting electrode for cell immobilization. For this purpose, cells of Pseudomonas fluorescens were immobilized on the surface of the CNTEC electrode by means of gelatin which was then cross linked with glutaraldehyde. After optimization of experimental parameters like cell amount, pH and temperature, the system was calibrated for glucose. From the calibration graph the linear range was estimated as 0.5–4.0 mM with a response time of 100 s. Furthermore, substrate specificity and operational stability were investigated. Finally, the results that were obtained with CNTEC electrodes were compared with conventional graphite epoxy composite electrode (GECE) and as a result, higher current values (2 to 3 folds) were observed with CNTEC microbial biosensor.
A voice crying in the wilderness: Legislative oversight agencies' efforts to achieve utilization
Authors: VanLandingham Gary R. 
Published: February 2007

AbstractAlthough evaluation utilization literature has identified a wide range of practical actions that evaluators can take to maximize use of their work by policymakers, an emphasis on organizational independence can limit use of these strategies. This can restrict evaluators' role to that of a voice crying in the wilderness rather than speaking truth to power.
The impact of state physical education requirements on youth physical activity and overweight
Authors: Cawley John , Meyerhoefer Chad , Newhouse David 
Published: February 2007

AbstractTo combat childhood overweight in the US, which has risen dramatically in the past three decades, many medical and public health organizations have called for students to spend more time in physical education (PE) classes. This paper is the first to examine the impact of state PE requirements on student PE exercise time. It also exploits variation in state laws as quasi‐natural experiments in order to estimate the causal impact of PE on overall student physical activity and weight. We study nationwide data from the Youth Risk Behavior Surveillance System for 1999, 2001, and 2003 merged with data on state minimum PE requirements from the 2001 Shape of the Nation Report.We find that high school students with a binding PE requirement report an average of 31 additional minutes per week spent physically active in PE class. Our results also indicate that additional PE time raises the number of days per week that girls report having exercised vigorously or having engaged in strength‐building activity. We find no evidence that PE lowers BMI or the probability that a student is overweight.We conclude that raising PE credit requirements may make girls more physically active overall but there is not yet the scientific base to declare raising PE requirements an anti‐obesity initiative for either boys or girls. Copyright © 2007 John Wiley & Sons, Ltd.
The role of ‘reference goods’ in contingent valuation: should we help respondents to ‘construct’ their willingness to pay?
Authors: Smith Richard D. 
Published: February 2007

AbstractA general population sample of 135 Australian respondents completed one of four contingent valuation surveys that asked them to value health benefits either in the absence of an explicit reference good or in the presence of one of three different forms of reference good. Results suggest that respondents have a ‘ball‐park’ figure that is then challenged by the reference good. For values that appear far lower than, or similar to, this ‘ball‐park’ figure, the reference good has littlequantitativeeffect, butqualitativelyappears to help respondents in their confidence in this value being their actual WTP. The implications for CV research in health care are outlined in the discussion. Copyright © 2007 John Wiley & Sons, Ltd.
Placental ultrasonography
Authors: King Donald Latham 
Published: February 2007

AbstractUltrasonography is the preferred technique for placental localization. It permits a comparatively precise estimate of the separation of the lower placental margin and internal cervical os. Six false positive diagnoses of placenta previa occurred in a series of 244 patients. There were no false negative diagnoses. The diagnosis of placenta previa was confirmed as correct in ten patients. Determination of the location of the lower margin of a posterior placenta obscured by the overlying fetus may be assisted by measurement of the separation of the anterior sacral margin and the fetal head when the latter is dipping into the pelvis. A separation of greater than 15 millimeters usually indicates extension of the lower placental margin over the sacral promontory and onto the lower uterine segment.
A digitized, direct contact b‐scanner for ophthalmic application
Authors: Holasek E. , Sokollu A. , Purnell E. W. 
Published: February 2007

AbstractThis paper presents the principles of a portable compact instrument utilizing a digital control system and providing B‐scan displays. The instrument is designed exclusively for ophthalmic applications. The system is comprised of a self‐contained scanning head and a signal display unit. The entire unit can easily be rolled to the patient's bedside or into the operating room. A programmed pulse generator provides signals for incremental angular positioning of the transducer as well as signals for the formation of the display. The transducer is moved by a stepping motor to establish the incremental sector scan. Display sweeps are generated by digital‐to‐analog conversion to circumvent the use of mechanically‐driven position sensors as used in conventional systems.