Young children and the say/mean distinction: verbatim and paraphrase recognition in narrative and nursery rhyme contexts

Children's ability to distinguish between the text, what was said, and the intentional structure, what was meant, was interrogated by means of verbatim and paraphrase questions in two types of discourse, narratives and nursery rhymes. Three- to seven-year-olds participated (n = 119, mean age 5.1). There was an interaction between the type of discourse and the younger children's ability to separate wording from intentional structure. In the narrative form they had difficulty rejecting true paraphrases when asked to focus on wording, while in the nursery rhyme form the difficulty was accepting a true paraphrase when asked to focus on intention.

Structural and functional alterations of the peritoneum after prolonged exposure to dialysis solutions: role of aminoguanidine

OBJECTIVE

The effect of long-term use of high glucose dialysate on peritoneal structure and function, and its relation with accumulation of advanced glycosylation end-product (AGE) in the peritoneum was investigated in this study.

METHODS

Dialysates with 4.25% glucose were injected into the peritoneal cavity of normal rats for 12 weeks without (PD, n = 7) and with (1 g/L, PD+AG, n = 7) aminoguanidine in their drinking water. Rats not having intraperitoneal (IP) injection served as control (n = 9). After 12 weeks of IP injection, a 2-hour peritoneal equilibration test (PET) was performed using 30 mL 4.25% glucose dialysate. Intraperitoneal volume (IPV), dialysate-to-plasma urea ratio at 2 hours (D/P2), the ratio of dialysate glucose at 2 hours to initial dialysate glucose (D2/D0), and the peritoneal fluid absorption rate (Qa) were evaluated. After the PET, samples of the parietal peritoneum were taken for hematoxylin and eosin (H&E) staining and immunohistochemical staining for AGE.

RESULTS

The IPV and D2/D0 glucose were significantly lower and Qa and D2/P2 urea significantly higher in the PD group than in the control group. Aminoguanidine reversed in part the changes in IPV and D2/P2 urea in the PD group; it had no effect on Qa and D2/D0 glucose. The H&E staining showed a linear mesothelial lining with negligible cells and capillaries in the narrow submesothelial space in the control group. Mesothelial denudation and submesothelial infiltration of monocytes and capillary formation were observed in the PD group. Mesothelial denudation was relatively intact in the PD+AG group compared with the PD group. Submesothelial monocyte infiltration and capillary formation in the PD+AG group were not as prominent as in the PD group. Positive AGE staining was found in the submesothelial space, vascular walls, and endomysium in the PD group, while it was markedly attenuated in PD+AG group and negligible in the control group.

CONCLUSION

Long-term use of high glucose solutions induced peritoneal AGE accumulation and mesothelial denudation, and increased peritoneal permeability and peritoneal fluid absorption rate. Inhibition of peritoneal AGE accumulation prevented those functional and structural damages to the peritoneum.

Identification of frequently recognized dimorphic T-cell epitopes in plasmodium falciparum merozoite surface protein-1 in West and East Africans: lack of correlation of immune recognition and allelic prevalence

The merozoite surface protein-1 (MSP1) is the most studied malaria blood-stage vaccine candidate. Lymphokines such as interferon gamma (IFN-gamma) and interleukin 4 (IL-4) may mediate blood-stage specific protection. Here we identify Plasmodiumfalciparum MSP1 T-cell epitopes capable of rapid induction of IFN-gamma and/or IL-4 from peripheral blood mononuclear cells of East and West African donors. Both allelic forms of these novel MSP1 T-cell epitopes were stimulatory. An unusually high numbers of Gambian responders (> 80%) to these epitopes were observed, suggesting that MSPI reactivity may have been underestimated previously in this population. Surprisingly, IFN-gamma responses to allelic T-cell epitopes failed to correlate with differential antigenic exposure in The Gambia compared to Kenya. These results suggest an unexpected level of immunoregulation of IFN-gamma response with variable allelic T-cell reactivity independent of the level of antigenic exposure. Further analysis of the mechanisms determining this response pattern may be required if vaccines are to overcome this allelic reactivity bias in malaria-exposed populations.

Bearing illness and injury

This qualitative study examined how individuals with catastrophic illness and injury managed their personal and social world. The 28 males and females had endured their chronic conditions from 3 to 25 years prior to the study. Participants were individually interviewed. Responses were analyzed using grounded theory methods. Individuals with catastrophic illness and injury experienced three phases in bearing their situation: finding out, facing reality, and managing reality. Individuals did not progress through stages as has been argued by stage theorists. Rather, the phases flowed together and were reexperienced continuously. Individuals employed three strategies--protecting, modifying, and boosting--in all of the phases to help them endure their circumstances.

Stabilization of molecular atoms

We demonstrate the possibility of stabilizing the motion of ion-pair states through the use of external electric and magnetic fields. In conjunction with the Coulomb force, these fields can be engineered so as to lead to the creation of outer equilibrium points which can support non-spreading coherent wavepackets and long-lived states. Specific application is made to the H(+)-H- ion pair, recently investigated using threshold ion-pair production spectroscopy (TIPPS).

Achieving aesthetic excellence through an outcome-based restorative treatment rationale

The conceptual basis of restorative-driven implant dentistry is well established among clinicians. Its implementation includes the development of a prosthetic blue-print that will serve as a guide throughout therapy. While these concepts may be applied to prosthetic dentistry in general, their benefits are most compelling in the treatment of the aesthetic zone. This article demonstrates a systematic multidimensional approach for the establishment and incorporation of definitive aesthetic objectives throughout the diagnostic, adjunctive, and restorative treatment phases.

Transitional custom abutments: optimizing aesthetic treatment in implant-supported restorations

As the discipline of implant prosthodontics continues to evolve, additional emphasis has been focused on the role of adequate emergence profiles and peri-implant soft tissue contours. Despite the development of anatomically shaped healing abutments, currently advocated techniques exhibit clinical limitations. This article introduces the transitional custom abutment technique as a method of manipulating the supra-implant soft tissue contours so that optimal emergence profiles and increased restorative flexibility can be achieved in the treatment of patients with compromised fixture angulation.

Purification of chitinolytic protein from Rehmannia glutinosa showing N-terminal amino acid sequence similarity to thaumatin-like proteins

We have purified a 21-kDa protein, designated as P1, from Rehmannia glutinosa to homogeneity by ammonium sulfate precipitation, anion exchange chromatography, hydrophobic interaction chromatography, and preparative native PAGE. The purified P1 had chitin degradation activity. The N-terminal amino acid sequence of P1 indicated that it is very similar to those of thaumatin and other reported thaumatin-like proteins.

Interleukin 10-mediated immunosuppression by a variant CD4 T cell epitope of Plasmodium falciparum

The immunodominant CD4 T cell epitope region, Th2R, of the circumsporozoite protein of Plasmodium falciparum is highly polymorphic. Such variation might be utilized by the parasite to escape from or interfere with CD4 T cell effector functions. Here, we show that costimulation with naturally occurring altered peptide ligands (APL) can induce a rapid change from IFNgamma production to the immunosuppressive mediator interleukin 10 (IL-10). This mechanism may contribute to the low levels of T cell responses observed to this pathogen in malaria-endemic areas.

Broadly distributed T cell reactivity, with no immunodominant loci, to the pre-erythrocytic antigen thrombospondin-related adhesive protein of Plasmodium falciparum in West Africans

Protective immunity to malaria has been achieved in human volunteers utilizing the pre-erythrocytic Plasmodium falciparum antigen, the circumsporozoite protein (CS). However, T cell reactivity to CS is focused on several highly polymorphic T cell epitope regions, potentially limiting the efficacy of any vaccine to specific malaria strains. Another important pre-erythrocytic malaria antigen, the thrombospondin-related adhesive protein (TRAP), can induce protection in animal models of malaria, but knowledge of human T cell responses is limited to the identification of CD8 T cell epitopes, with no CD4 epitopes identified to date. This comprehensive study assessed reactivity to overlapping peptides spanning almost the whole of P. falciparum TRAP (PfTRAP), as well as peptides selected on the basis of HLA class II-binding motifs. A total of 50 naturally exposed Gambian adults were assessed to define 26 T cell epitopes in PfTRAP capable of inducing rapid IFN-gamma or IL-4 production, as assessed by enzyme-linked immunospot assays. In contrast to the CS protein, this reactivity was broadly distributed along the length of TRAP. Moreover, of the 26 epitopes identified, 10 were found to be conserved in West Africa.

Altered peptide ligands narrow the repertoire of cellular immune responses by interfering with T-cell priming

Variation in epitopes of infectious pathogens inhibits various effector functions of T lymphocytes through antagonism of the T-cell receptor. However, a more powerful strategy for immune evasion would be to prevent the induction of T-cell responses. We report here mutual 'interference' with the priming of human T-cell responses by a pair of naturally occurring variants of a malaria cytotoxic T-cell epitope. Interference with priming also occurs in vivo for a murine malaria T-cell epitope. Reshaping of the T-cell repertoire by such immune interference during naive T-cell induction may provide a general mechanism for observed patterns of immunodominance and persistence by many polymorphic pathogens.

Predictable elastomeric impressions in advanced fixed prosthodontics: a comprehensive review

Despite advances in dental material technology, the predictable procurement of accurate impressions for the fabrication of complex fixed prosthodontic restorations remains an elusive objective. The technical challenges and potential negative sequelae are exponentially magnified in advanced applications that involve multiple abutments and preparatory phases. A protocol for consistently achieving accurate impressions with the use of polyether impression materials and automatic instrumentation is presented and illustrated with multiple clinical examples. The technique is capable of yielding reliable results in extensive cases and requires minimal support from auxiliary personnel.

Genetic mechanisms underlying apimaysin and maysin synthesis and corn earworm antibiosis in maize (Zea mays L.)

C-glycosyl flavones in maize silks confer resistance (i.e., antibiosis) to corn earworm (Helicoverpa zea [Boddie]) larvae and are distinguished by their B-ring substitutions, with maysin and apimaysin being the di- and monohydroxy B-ring forms, respectively. Herein, we examine the genetic mechanisms underlying the synthesis of maysin and apimaysin and the corresponding effects on corn earworm larval growth. Using an F2 population, we found a quantitative trait locus (QTL), rem1, which accounted for 55.3% of the phenotypic variance for maysin, and a QTL, pr1, which explained 64.7% of the phenotypic variance for apimaysin. The maysin QTL did not affect apimaysin synthesis, and the apimaysin QTL did not affect maysin synthesis, suggesting that the synthesis of these closely related compounds occurs independently. The two QTLs, rem1 and pr1, were involved in a significant epistatic interaction for total flavones, suggesting that a ceiling exists governing the total possible amount of C-glycosyl flavone. The maysin and apimaysin QTLs were significant QTLs for corn earworm antibiosis, accounting for 14. 1% (rem1) and 14.7% (pr1) of the phenotypic variation. An additional QTL, represented by umc85 on the short arm of chromosome 6, affected antibiosis (R2 = 15.2%), but did not affect the synthesis of the C-glycosyl flavones.

Molecular analysis of prion protein gene (PRNP) in Korean patients with Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD), a relatively uncommon human dementia, is caused by an unconventional slow infectious agent. Several cases of CJD, clinically or histopathologically diagnosed, have been reported in Korea. In order to confirm the diagnosis of CJD and also differential diagnosis of sporadic and familial types of CJD in Korea, we studied two patients who had symptoms of CJD. The histopathological and immunohistochemical studies showed spongiform neurodegeneration and expression of abnormal isoform of prion protein (PrPSc) in astrocytes. Thus, these two patients were diagnosed CJD. To investigate whether these patients were sporadic or familial type of CJD, the molecular analyses of the prion protein gene (PRNP) were done by restriction fragment length polymorphism (RFLP) and DNA sequencing. In the cases of a healthy Korean and two CJD patients, no point mutation was detected in the known hot spots (178, 180, 200, 210, and 232) and they exhibited wild type PRNP sequences. We concluded that both patients have a sporadic type of CJD, but not familial type.

Immune evasion in malaria: altered peptide ligands of the circumsporozoite protein

T cells are central to immunity in malaria. CD4+ helper T cells favour the generation of high-affinity antibodies that are effective against blood stages and they are necessary to establish immunological memory. The intrahepatic stage of infection can be eliminated by specific CD8+ cytotoxic T cells (CTL). Cytokines secreted by CD4+ T cells may also contribute to liver stage immunity. Evolution has selected varied mechanisms in pathogens to avoid recognition by T cells. T cells recognize foreign epitopes as complexes with host major histocompatibility (MHC) molecules. Thus, a simple form of evasion is to mutate amino acid residues which allow binding to an MHC allele. Recently, more sophisticated forms of polymorphic evasion have been described. In altered peptide ligand (APL) antagonism, the concurrent presentation of particular closely related epitope variants can prevent memory T cell effector functions such as cytotoxicity, lymphokine production and proliferation. In immune interference, the effect of the concurrent presentation of such related epitope variants can go a step further and prevent the induction of memory T cells from naive precursors. The analysis of immune responses to a protein of P. falciparum, the circumsporozoite protein (CSP), indicates that the malaria parasite may utilize these evasion strategies.

Quantitative trait loci and metabolic pathways

The interpretation of quantitative trait locus (QTL) studies is limited by the lack of information on metabolic pathways leading to most economic traits. Inferences about the roles of the underlying genes with a pathway or the nature of their interaction with other loci are generally not possible. An exception is resistance to the corn earworm Helicoverpa zea (Boddie) in maize (Zea mays L.) because of maysin, a C-glycosyl flavone synthesized in silks via a branch of the well characterized flavonoid pathway. Our results using flavone synthesis as a model QTL system indicate: (i) the importance of regulatory loci as QTLs, (ii) the importance of interconnecting biochemical pathways on product levels, (iii) evidence for "channeling" of intermediates, allowing independent synthesis of related compounds, (iv) the utility of QTL analysis in clarifying the role of specific genes in a biochemical pathway, and (v) identification of a previously unknown locus on chromosome 9S affecting flavone level. A greater understanding of the genetic basis of maysin synthesis and associated corn earworm resistance should lead to improved breeding strategies. More broadly, the insights gained in relating a defined genetic and biochemical pathway affecting a quantitative trait should enhance interpretation of the biological basis of variation for other quantitative traits.

Evolutionary matches of enzyme and transporter capacities to dietary substrate loads in the intestinal brush border

Safety factors of enzymes and transporters are defined as the ratio of Vmax (maximal reaction rates at high substrate concentrations) to the reaction rate under actual physiological conditions. Although corresponding safety factors have been measured for macroscopic biological structures and for human-engineered structures, safety factors have been little studied at the molecular level. Some evolutionary considerations suggest that safety factors should be modestly in excess of 1.0 ("enough but not too much") and should tend to be similar for the various steps of a pathway consisting of two or more elements arranged in series. Hence we used a preparation of intact mouse small intestine to measure Vmax values (capacities) of brush-border sucrase (yielding glucose plus fructose) and of the brush-border glucose transporter, for comparison with each other and with dietary sucrose loads. Load was manipulated by varying dietary sucrose level or by studying lactating mice with increased energy requirements. Capacities both of sucrase and the glucose transporter increased with sucrose load (i.e., both proteins are inducible) and remained approximately matched to each other except on a carbohydrate-free diet. Their safety factors decreased from ca. 2.7 at low load to 1.0 at high load. Thus, neither sucrase nor the glucose transporter is the rate-limiting step for sucrose digestion; both steps are equally limiting. The modest safety factors and matched capacities must be genetically programmed through natural selection, with benefits of excess capacities being balanced against costs of biosynthetic energy and limited membrane space.

A method for assaying intestinal brush-border sucrase in an intact intestinal preparation

Small intestinal brush-border hydrolases usually are assayed in intestinal mucosal homogenates resuspended in solutions of unphysiological ionic composition. Thus, extrapolation of measured Vmax values (maximal reaction rates at high substrate concentrations) to in vivo conditions, hence comparison with physiological substrate loads, is uncertain. We therefore have developed a sucrase assay in an intact preparation of mouse small intestine, an everted intestinal sleeve incubated in a physiological Ringer's solution. As in homogenate studies, sucrase is assayed by glucose production measured colorimetrically, but uptake of liberated glucose into the intestinal sleeve is prevented by the transport inhibitor phlorizin. The coefficient of variation of Vmax is 16% for sleeves from the same mouse and 8% for mean values from different mice. Sleeve sucrase activity is abolished by the inhibitor castanospermine. Activity in sleeves and homogenates proves to be the same when measured under identical solution conditions, but variations in assay conditions cause large activity changes from values measured in physiological solutions.

Plant regeneration from mesophyll protoplasts ofDianthus superbus

Leaf mesophyll protoplasts ofDianthus superbus were cultured at a density of 5 × 10(4) protoplasts/ml and divided at about 18% plating efficiency in MS liquid medium supplemented with 0.5 mg/L BAP, 2.0 mg/L NAA and 9% mannitol after 2 weeks. Protocolonies formed after 3 to 4 weeks of culture in the dark at 27°C. These colonies were transferred to continuous illumination (21.5 μE m(-2) sec(-1)) for 2 weeks where most of the colonies divided to form microcalli, about 2 mm in diameter. Subsequently, green microcalli were transferred to MS solidified medium with 2.0 mg/L 2,4-D that induced shoot-forming calli after 4 weeks. These calli were transferred onto N6-2 medium containing 0.1 mg/L 2,4-D, 0.1 mg/L NAA, 2.0 mg/L kinetin and 2.0 g/L casein hydrolysate and were cultured under light. After 5 weeks the calli gave rise to multiple shoots (10 to 15 per callus). Upon transfer to MS medium containing 2.0 mg/L NAA, individual shoots were rooted in 4 weeks. The regenerants were successfully transplanted into potting soil.

Localised tetanus in two cats after ovariohysterectomy

Localised tetanus was diagnosed in two cats 14 and 21 days after ovariohysterectomy by a left flank surgical approach. The diagnosis in each case was based on their history, clinical signs and diagnostic investigations which excluded other possible diagnoses. Both cats showed scoliosis of the lumbar spine and left hind limb spasticity. One cat's clinical signs were exacerbated after the administration of corticosteroids. One cat was treated with oral amoxycillin and diazepam, and the second cat received penicillin, tetanus antitoxin, methocarbarnol and diazepam. Both cats improved after treatment but recovery was prolonged and the spasticity did not resolve until 12 weeks after diagnosis in one cat. The second cat was lost to follow up after 8 weeks.

Ontogeny of membrane and soluble amino-oligopeptidases in rat intestine

Intestinal amino-oligopeptidase (AOP) plays an essential role in protein digestion. To characterize its postnatal development, we measured AOP activity in intestinal membrane and cytosolic fractions in suckling and weaned rats, compared the subunit structures of the membrane and soluble enzymes, and assessed the biochemical relationship of these peptidases. At weaning, jejunal membrane AOP activity doubled while soluble AOP activity in the ileum fell abruptly. The maturational increase in the molecular mass of ileal membrane AOP was due to alterations in the N-linked glycosylation of this protein. Ileal membrane and soluble AOP exhibited similar substrate affinities, pH optima, inhibition characteristics, and antigenic epitopes. However, soluble AOP was 25-35 kDa smaller than the membrane enzyme. Peak incorporation of [35S]methionine into ileal brush-border AOP preceded maximal radioactivity in soluble AOP, suggesting that the membrane peptidase is a precursor of the soluble enzyme. We conclude that membrane and soluble AOP are closely related proteins with distinct developmental profiles and that the soluble peptidase may be derived from endocytosis of the membrane enzyme.

Genetic diversity among progenitors and elite lines from the Iowa Stiff Stalk Synthetic (BSSS) maize population: comparison of allozyme and RFLP data

Data for restriction fragment length polymorphisms (RFLPs) of 144 clone-enzyme combinations and for 22 allozyme loci from 21 U.S. Corn Belt maize (Zea mays L.) inbreds were analyzed. The genetic materials included 14 progenitors of the Iowa Stiff Stalk Synthetic (BSSS) maize population, both parents of one missing BSSS progenitor, four elite inbreds derived from BSSS, and inbred Mo17. Objectives were to characterize the genetic variation among these 21 inbreds for both allozymes and RFLPs, to compare the results from both types of molecular markers, and to estimate the proportion of unique alleles in the BSSS progenitors. Genetic diversity among the 21 inbreds was substantially greater for RFLPs than for allozymes, but the percentages of unique RFLP variants (27%) and unique allozyme alleles (25%) in the BSSS progenitors were similar. Genetic distances between inbreds, estimated as Rogers' distance (RD), were, on average, twice as large for RFLP (0.51) as for allozyme data (0.24). RDs obtained from allozyme and RFLP data for individual line combinations were only poorly correlated (r = 0.23); possible reasons for discrepancies are discussed. Principal component analysis of RFLP data, in contrast to allozyme data, resulted in separate groupings of the ten BSSS progenitors derived from the 'Reid Yellow Dent' population, the four BSSS elite lines, and Mo17. The remaining six BSSS progenitors were genetically rather diverse and contributed a large number of rare alleles to BSSS. The results of this study corroborate the fact that RFLPs are superior to allozymes for characterizing the genetic diversity of maize breeding materials, because of (1) the almost unlimited number of markers available and (2) the greater amount of polymorphisms found. In particular, RFLPs allow related lines and inbreds with common genetic background to be identified, but a large number of probe-enzyme combinations is needed to estimate genetic distances with the precision required.