In the spleens of young, adult mice there exist naturally occurring killer lymphocytes with specificity for mouse Moloney leukemia cells. The lytic activity was directed against syngeneic or allogeneic Moloney leukemia cells to a similar extent, but was primarily expressed when tested against in vitro grown leukemia cells. Two leukemias of non-Moloney origin were resistant and so was the mastocytoma line P815. Although killer activity varied between different strains of mice, the specificity of lysis was the same as indicated by competition experiments using unlabeled Moloney or other tumor cells as inhibitors in the cytotoxic assays. Capacity to compete and sensitivy to lysis by the killer cells were found to be highly positively correlated. Analysis of the kinetics of the cytotoxic assay revealed a rapid induction of lysis within one to four hours, arguing against any conventional in vitro induction of immune response. No evidence was found of soluble factors playing any role in the cytolytic assay.

Eukaryotic cells respond to many hormones and neurotransmitters with increased activity of the enzyme phospholipase C and a subsequent rise in the concentration of intracellular free calcium ([Ca2+]i). The increase in [Ca2+]i occurs as a result of the release of Ca2+ from intracellular stores and an influx of Ca2+ through the plasma membrane; this influx of Ca2+ may or may not be store-dependent. Drosophila transient receptor potential (TRP) proteins and some mammalian homologues (TRPC proteins) are thought to mediate capacitative Ca2+ entry. Here we describe the molecular mechanism of store-depletion-independent activation of a subfamily of mammalian TRPC channels. We find that hTRPC6 is a non-selective cation channel that is activated by diacylglycerol in a membrane-delimited fashion, independently of protein kinases C activated by diacylglycerol. Although hTRPC3, the closest structural relative of hTRPC6, is activated in the same way, TRPCs 1, 4 and 5 and the vanilloid receptor subtype 1 are unresponsive to the lipid mediator. Thus, hTRPC3 and hTRPC6 represent the first members of a new functional family of second-messenger-operated cation channels, which are activated by diacylglycerol.

Thousands of long intervening noncoding RNAs (lincRNAs) have been identified in mammals. To better understand the evolution and functions of these enigmatic RNAs, we used chromatin marks, poly(A)-site mapping and RNA-Seq data to identify more than 550 distinct lincRNAs in zebrafish. Although these shared many characteristics with mammalian lincRNAs, only 29 had detectable sequence similarity with putative mammalian orthologs, typically restricted to a single short region of high conservation. Other lincRNAs had conserved genomic locations without detectable sequence conservation. Antisense reagents targeting conserved regions of two zebrafish lincRNAs caused developmental defects. Reagents targeting splice sites caused the same defects and were rescued by adding either the mature lincRNA or its human or mouse ortholog. Our study provides a roadmap for identification and analysis of lincRNAs in model organisms and shows that lincRNAs play crucial biological roles during embryonic development with functionality conserved despite limited sequence conservation.

Reference curves for stature and weight in British children have been available for the past 30 years, and have recently been updated. However weight by itself is a poor indicator of fatness or obesity, and there has never been a corresponding set of reference curves to assess weight for height. Body mass index (BMI) or weight/height has been popular for assessing obesity in adults for many years, but its use in children has developed only recently. Here centile curves for BMI in British children are presented, from birth to 23 years, based on the same large representative sample as used to update the stature and weight references. The charts were derived using Cole's LMS method, which adjusts the BMI distribution for skewness and allows BMI in individual subjects to be expressed as an exact centile or SD score. Use of the charts in clinical practice is aided by the provision of nine centiles, where the two extremes identify the fattest and thinnest four per 1000 of the population.

Somatic cell nuclear transfer, cell fusion, or expression of lineage-specific factors have been shown to induce cell-fate changes in diverse somatic cell types. We recently observed that forced expression of a combination of three transcription factors, Brn2 (also known as Pou3f2), Ascl1 and Myt1l, can efficiently convert mouse fibroblasts into functional induced neuronal (iN) cells. Here we show that the same three factors can generate functional neurons from human pluripotent stem cells as early as 6 days after transgene activation. When combined with the basic helix-loop-helix transcription factor NeuroD1, these factors could also convert fetal and postnatal human fibroblasts into iN cells showing typical neuronal morphologies and expressing multiple neuronal markers, even after downregulation of the exogenous transcription factors. Importantly, the vast majority of human iN cells were able to generate action potentials and many matured to receive synaptic contacts when co-cultured with primary mouse cortical neurons. Our data demonstrate that non-neural human somatic cells, as well as pluripotent stem cells, can be converted directly into neurons by lineage-determining transcription factors. These methods may facilitate robust generation of patient-specific human neurons for in vitro disease modelling or future applications in regenerative medicine.

The rat neuroblastoma B104 cell line, which originated in the central nervous system, was able to proliferate in the absence of serum in synthetic medium supplemented with insulin, transferrin, progesterone, selenium, and putrescine. When added individually, each supplement had little or no effect; however, in combination there was a marked synergistic effect on cell number. The cells attained the same saturation density in this medium as in medium with 10% fetal calf serum added. More extensive process formation was observed in the supplemented medium, and other differentiated properties were retained as well.

The concept of intrinsic efficacy has been enshrined in pharmacology for half of a century, yet recent data have revealed that many ligands can differentially activate signaling pathways mediated via a single G protein-coupled receptor in a manner that challenges the traditional definition of intrinsic efficacy. Some terms for this phenomenon include functional selectivity, agonist-directed trafficking, and biased agonism. At the extreme, functionally selective ligands may be both agonists and antagonists at different functions mediated by the same receptor. Data illustrating this phenomenon are presented from serotonin, opioid, dopamine, vasopressin, and adrenergic receptor systems. A variety of mechanisms may influence this apparently ubiquitous phenomenon. It may be initiated by differences in ligand-induced intermediate conformational states, as shown for the beta(2)-adrenergic receptor. Subsequent mechanisms that may play a role include diversity of G proteins, scaffolding and signaling partners, and receptor oligomers. Clearly, expanded research is needed to elucidate the proximal (e.g., how functionally selective ligands cause conformational changes that initiate differential signaling), intermediate (mechanisms that translate conformation changes into differential signaling), and distal mechanisms (differential effects on target tissue or organism). Besides the heuristically interesting nature of functional selectivity, there is a clear impact on drug discovery, because this mechanism raises the possibility of selecting or designing novel ligands that differentially activate only a subset of functions of a single receptor, thereby optimizing therapeutic action. It also may be timely to revise classic concepts in quantitative pharmacology and relevant pharmacological conventions to incorporate these new concepts.

1. Inward currents in chromaffin cells were studied with the patch-clamp technique (Hamill, Marty, Neher, Sakmann & Sigworth, 1981). The intracellular solution contained 120 mM-Cs(+) and 20 mM-tetraethylammonium (TEA(+)). Na(+) currents were studied after blockade of Ca(2+) channels with 1 mM-Co(2+) applied externally. Ca(2+) currents were recorded after eliminating Na(+) currents with tetrodotoxin (TTX). The current recordings were obtained in cell-attached, outside-out and whole-cell recording configurations (Hamill et al. 1981).2. Single channel measurements gave an elementary current amplitude of 1 pA at -10 mV for Na(+) channels. This amplitude increased with hyperpolarization between -10 and -40 mV, but did not vary significantly between -40 and -70 mV.3. The mean Na(+) channel open time was 1 ms at -30 mV. This open time decreased both with depolarization and hyperpolarization. Its value was close to the time constant of inactivation, tau(h), above -20 mV.4. Ensemble fluctuation analysis of Na(+) currents gave results consistent with those of single channel measurements. Noise power spectra obtained between -35 mV and 0 mV could be fitted with a single Lorentzian. A range of Na(+) channel densities of 1.5-10 channels per mum(2) was calculated.5. Cell-attached single Ca(2+) channel recordings were obtained in isotonic BaCl(2) solution. The single channel amplitude was 0.9 pA at -5 mV, and it became smaller for positive potential values.6. At -5 mV, single Ba(2+) currents appeared as bursts of 1.9 ms mean duration containing on the average 0.6 short gaps. The burst duration was larger at positive potentials.7. Ensemble fluctuation analysis of Ca(2+) channels was performed on whole-cell recordings in external solutions containing isotonic BaCl(2) or external Ca(2+) (Ca(o)) concentrations of 1 and 5 mM. The unit amplitude calculated in the former case was similar to that obtained in single channel measurements.8. Noise power spectra of Ca(2+) or Ba(2+) currents could be fitted by the sum of two, but not one, Lorentzian components.9. Tail currents could be fitted by the sum of two exponential components. The corresponding time constants had values close to those obtained with noise analysis.10. The rising phase of Ca(2+) and Ba(2+) currents was sigmoid. It could be fitted by the sum of three exponentials. The time constant of the largest amplitude component, tau(1), was similar to the time constants of the slow component observed in noise and tail experiments. This time constant also corresponded to the burst duration obtained in single channel measurements.11. The value of tau(1) was larger in 5 mM-Ca(o) and in isotonic Ba(2+) than in 5 mM-Ba(o). Thus, the kinetic properties of Ca(2+) channels depend on the nature and concentration of the permeating ion.12. A simple kinetic scheme is proposed to model the activation pathway of Ca(2+) channels.13. Currents in 1 mM-Ca(o) and 5 mM-Ca(o) showed clear reversals around +53 mV and +64 mV respectively. The outward currents observed above these potentials are most probably due to Cs(+) ions flowing through Ca(2+) channels.14. The instantaneous current-voltage relation was obtained from tail current data in the range -70 to +100 mV in 5 mM-Ca(o). The resulting curve displayed an inflexion point around the reversal potential.15. Very little inactivation of Ca(2+) currents was observed. However, a slow current decline was observed in some cells above +10 mV.16. Conditioning prepulses to positive potentials had potentiating or depressing effects on Ca(2+) currents depending on whether the test pulse lay below or above the maximal current potential. The potentiating effect may be linked to the slowest component of the current rise observed below +10 mV. The depressing effect may be related to the slow decline obtained above +10 mV.17. Analysis of ensemble variance and of tail current amplitudes suggested that the opening probability of Ca(2+) channels was at least 0.9 above +40 mV.18. A slow rundown of Ca(2+) currents was observed in whole-cell recordings. The speed of the rundown was dependent on intracellular Ca(2+) concentration. The rundown was apparently due to a progressive elimination of the channels available for activation.19. The density of Ca(2+) channels (before rundown) was estimated at 5-15/mum(2).20. In cell-attached experiments, inward current channels were often seen to follow action potentials. These events did not appear to be the usual Na(+) and Ca(2+) currents. They were probably due to cation influx of either Na(+) or Ba(2+), depending on the pipette solution, through Ca(2+)-dependent channels. Voltage-independent single channel activity observed in whole-cell and outside-out recordings may be due to the same channels.

Antiretroviral therapy fails to cure HIV-1 infection because latent proviruses persist in resting CD4(+) T cells. T cell activation reverses latency, but <1% of proviruses are induced to release infectious virus after maximum in vitro activation. The noninduced proviruses are generally considered defective but have not been characterized. Analysis of 213 noninduced proviral clones from treated patients showed 88.3% with identifiable defects but 11.7% with intact genomes and normal long terminal repeat (LTR) function. Using direct sequencing and genome synthesis, we reconstructed full-length intact noninduced proviral clones and demonstrated growth kinetics comparable to reconstructed induced proviruses from the same patients. Noninduced proviruses have unmethylated promoters and are integrated into active transcription units. Thus, it cannot be excluded that they may become activated in vivo. The identification of replication-competent noninduced proviruses indicates that the size of the latent reservoir-and, hence, the barrier to cure-may be up to 60-fold greater than previously estimated.

We previously developed a cladistic approach to identify subsets of haplotypes defined by restriction endonuclease mapping or DNA sequencing that are associated with significant phenotypic deviations. Our approach was limited to segments of DNA in which little recombination occurs. In such cases, a cladogram can be constructed from the restriction site or sequence data that represents the evolutionary steps that interrelate the observed haplotypes. The cladogram is used to define a nested statistical design to identify mutational steps associated with significant phenotypic deviations. The central assumption behind this strategy is that any undetected mutation causing a phenotypic effect is embedded within the same evolutionary history that is represented by the cladogram. The power of this approach depends upon the confidence one has in the particular cladogram used to draw inferences. In this paper, we present a strategy for estimating the set of cladograms that are consistent with a particular sample of either restriction site or nucleotide sequence data and that includes the possibility of recombination. We first evaluate the limits of parsimony in constructing cladograms. Once these limits have been determined, we construct the set of parsimonious and nonparsimonious cladograms that is consistent with these limits. Our estimation procedure also identifies haplotypes that are candidates for being products of recombination. If recombination is extensive, our algorithm subdivides the DNA region into two or more subsections, each having little or no internal recombination. We apply this estimation procedure to three data sets to illustrate varying degrees of cladogram ambiguity and recombination.

Epithelium is the tissue phenotype of early embryos and primitive adults of the chordate phylum. A second tissue type, however, is produced by epithelial-mesenchymal transformation (EMT) in higher chordates, such as vertebrata. Mesenchymal cells have the ability, which true epithelia do not, to invade and migrate through the extracellular matrix (ECM) to create dramatic cell transpositions. The first-formed or primary mesenchymal cells in amniote vertebrates migrate from the primitive streak to differentiate into the mesodermal and endodermal epithelia. Definitive mesenchyme with connective tissue and muscle potentials arises from the epithelial mesoderm at about the same time as the neural crest mesenchyme forms from the ectoderm. Later on in embryogenesis. EMT is used to remodel unwanted epithelia, such as that of the palate medial edges. We discuss the mechanisms by which epithelial cells transform into mesenchyme and vice versa. On the one hand, cells activate putative mesenchymal master genes, turn off epithelial genes, and acquire motility machinery that allows them to interact in 3 dimensions (3D) with ECM via actin cortex while sliding their endoplasm into their new front ends. On the other hand, primary mesenchymal cells can reactivate epithelial regulatory genes, such as E-cadherin, turn off the motility machinery for invading ECM, and reexpress apical-basal polarity. We review the genes, such as FSP1, src, ras, and fos, that are activated in cells transforming to mesenchyme and the genes their neighbors activate to induce EMT, such as those for TGF beta, NT-3, and sonic hedgehog. Suspension in 3D collagen gels can induce adult epithelium to undergo EMT; alpha 5 beta 1 integrin is activated on surfaces in contact with collagen, including apical surfaces that do not normally express integrins. In vivo, it is possible that pathological manipulations of a cell's environment likewise induce EMT. Of the examples we give, the creation of invasive metastatic carcinoma cells by EMT is the most fearful. Interestingly, transfection of either metastatic cells or normal embryonic fibroblasts with the E-cadherin gene converts them to the epithelial phenotype. It may be possible in the future to manipulate the tissue phenotype of diseased cells to the advantage of the animal.

BACKGROUND

Measuring the quantity of miRNAs in tissues of different physiological and pathological conditions is an important first step to investigate the functions of miRNAs. Matched samples from normal state can provide essential baseline references to analyze the variation of miRNA abundance.

RESULTS

We provided expression data of 345 miRNAs in 40 normal human tissues, which identified universally expressed miRNAs, and several groups of miRNAs expressed exclusively or preferentially in certain tissue types. Many miRNAs with co-regulated expression patterns are located within the same genomic clusters, and candidate transcriptional factors that control the pattern of their expression may be identified by a comparative genomic strategy. Hierarchical clustering of normal tissues by their miRNA expression profiles basically followed the structure, anatomical locations, and physiological functions of the organs, suggesting that functions of a miRNA could be appreciated by linking to the biologies of the tissues in which it is uniquely expressed. Many predicted target genes of miRNAs that had specific reduced expression in brain and peripheral blood mononuclear cells are required for embryonic development of the nervous and hematopoietic systems based on database search.

CONCLUSIONS

We presented a global view of tissue distribution of miRNAs in relation to their chromosomal locations and genomic structures. We also described evidence from the cis-regulatory elements and the predicted target genes of miRNAs to support their tissue-specific functional roles to regulate the physiologies of the normal tissues in which they are expressed.

Biochemical methods are presented for determining the structure of spliced RNAs present in cells at low concentrations. Two cytoplasmic spliced viral RNAs were detected in CV-1 cells during the early phase of simian virus 40 (SV40) infection. One is 2200 nucleotides in length and is composed of two parts, 330 and 1900 nucleotides, mapping from approximately 0.67 to approximately 0.60 and from approximately 0.54 to approximately 0.14, respectively, on the standard viral map. The other is 2500 nucleotides long and also is composed of two parts, 630 and 1900 nucleotides mapping from approximately 0.67 to approximately 0.54 and from approximately 0.54 to approximately 0.14, respectively. Correlation of the structure of these mRNAs with the structure of the early SV40 proteins, small T antigen (17,000 daltons) and large T antigen (90,000 daltons), determined by others suggests that: (i) translation of the 2500-nucleotide mRNA yields small T antigen; (ii) translation of the 2200-nucleotide mRNA proceeds through the splice point in the RNA to produce large T antigen (and thus large T antigen is encoded in two separate regions of the viral genome); and (iii) the DNA sequences between approximately 0.67 and approximately 0.60 present in both mRNAs are translated in the same reading frame in both mRNAs to yield two separate gene products that have the same NH(2)-terminal sequence. Therefore, expression of the early SV40 genes is partially controlled at the level of splicing of RNAs.

BACKGROUND

Fluoropyrimidine-based chemotherapy plus the anti-vascular endothelial growth factor (VEGF) antibody bevacizumab is standard first-line treatment for metastatic colorectal cancer. We studied the effect of adding the anti-epidermal growth factor receptor (EGFR) antibody cetuximab to a combination of capecitabine, oxaliplatin, and bevacizumab for metastatic colorectal cancer.

METHODS

We randomly assigned 755 patients with previously untreated metastatic colorectal cancer to capecitabine, oxaliplatin, and bevacizumab (CB regimen, 378 patients) or the same regimen plus weekly cetuximab (CBC regimen, 377 patients). The primary end point was progression-free survival. The mutation status of the KRAS gene was evaluated as a predictor of outcome.

RESULTS

The median progression-free survival was 10.7 months in the CB group and 9.4 in the CBC group (P=0.01). Quality-of-life scores were lower in the CBC group. The overall survival and response rates did not differ significantly in the two groups. Treated patients in the CBC group had more grade 3 or 4 adverse events, which were attributed to cetuximab-related adverse cutaneous effects. Patients treated with cetuximab who had tumors bearing a mutated KRAS gene had significantly decreased progression-free survival as compared with cetuximab-treated patients with wild-type-KRAS tumors or patients with mutated-KRAS tumors in the CB group.

CONCLUSIONS

The addition of cetuximab to capecitabine, oxaliplatin, and bevacizumab resulted in significantly shorter progression-free survival and inferior quality of life. Mutation status of the KRAS gene was a predictor of outcome in the cetuximab group. (ClinicalTrials.gov number, NCT00208546.)

Staufen 1 (STAU1)-mediated messenger RNA decay (SMD) involves the degradation of translationally active mRNAs whose 3'-untranslated regions (3' UTRs) bind to STAU1, a protein that binds to double-stranded RNA. Earlier studies defined the STAU1-binding site within ADP-ribosylation factor 1 (ARF1) mRNA as a 19-base-pair stem with a 100-nucleotide apex. However, we were unable to identify comparable structures in the 3' UTRs of other targets of SMD. Here we show that STAU1-binding sites can be formed by imperfect base-pairing between an Alu element in the 3' UTR of an SMD target and another Alu element in a cytoplasmic, polyadenylated long non-coding RNA (lncRNA). An individual lncRNA can downregulate a subset of SMD targets, and distinct lncRNAs can downregulate the same SMD target. These are previously unappreciated functions of non-coding RNAs and Alu elements. Not all mRNAs that contain an Alu element in the 3' UTR are targeted for SMD even in the presence of a complementary lncRNA that targets other mRNAs for SMD. Most known trans-acting RNA effectors consist of fewer than 200 nucleotides, and these include small nucleolar RNAs and microRNAs. Our finding that the binding of STAU1 to mRNAs can be transactivated by lncRNAs uncovers an unexpected strategy that cells use to recruit proteins to mRNAs and mediate the decay of these mRNAs. We name these lncRNAs half-STAU1-binding site RNAs (1/2-sbsRNAs).

A multiple testing procedure is proposed for comparing two treatments when response to treatment is both dichotomous (i.e., success or failure) and immediate. The proposed test statistic for each test is the usual (Pearson) chi-square statistic based on all data collected to that point. The maximum number (N) of tests and the number (m1 + m2) of observations collected between successive tests is fixed in advance. The overall size of the procedure is shown to be controlled with virtually the same accuracy as the single sample chi-square test based on N(m1 + m2) observations. The power is also found to be virtually the same. However, by affording the opportunity to terminate early when one treatment performs markedly better than the other, the multiple testing procedure may eliminate the ethical dilemmas that often accompany clinical trials.

OBJECTIVE

To consider methods and related evidence for evaluating bias in non-randomised intervention studies.

METHODS

Systematic reviews and methodological papers were identified from a search of electronic databases; handsearches of key medical journals and contact with experts working in the field. New empirical studies were conducted using data from two large randomised clinical trials.

METHODS

Three systematic reviews and new empirical investigations were conducted. The reviews considered, in regard to non-randomised studies, (1) the existing evidence of bias, (2) the content of quality assessment tools, (3) the ways that study quality has been assessed and addressed. (4) The empirical investigations were conducted generating non-randomised studies from two large, multicentre randomised controlled trials (RCTs) and selectively resampling trial participants according to allocated treatment, centre and period.

RESULTS

In the systematic reviews, eight studies compared results of randomised and non-randomised studies across multiple interventions using meta-epidemiological techniques. A total of 194 tools were identified that could be or had been used to assess non-randomised studies. Sixty tools covered at least five of six pre-specified internal validity domains. Fourteen tools covered three of four core items of particular importance for non-randomised studies. Six tools were thought suitable for use in systematic reviews. Of 511 systematic reviews that included non-randomised studies, only 169 (33%) assessed study quality. Sixty-nine reviews investigated the impact of quality on study results in a quantitative manner. The new empirical studies estimated the bias associated with non-random allocation and found that the bias could lead to consistent over- or underestimations of treatment effects, also the bias increased variation in results for both historical and concurrent controls, owing to haphazard differences in case-mix between groups. The biases were large enough to lead studies falsely to conclude significant findings of benefit or harm. Four strategies for case-mix adjustment were evaluated: none adequately adjusted for bias in historically and concurrently controlled studies. Logistic regression on average increased bias. Propensity score methods performed better, but were not satisfactory in most situations. Detailed investigation revealed that adequate adjustment can only be achieved in the unrealistic situation when selection depends on a single factor.

CONCLUSIONS

Results of non-randomised studies sometimes, but not always, differ from results of randomised studies of the same intervention. Non-randomised studies may still give seriously misleading results when treated and control groups appear similar in key prognostic factors. Standard methods of case-mix adjustment do not guarantee removal of bias. Residual confounding may be high even when good prognostic data are available, and in some situations adjusted results may appear more biased than unadjusted results. Although many quality assessment tools exist and have been used for appraising non-randomised studies, most omit key quality domains. Healthcare policies based upon non-randomised studies or systematic reviews of non-randomised studies may need re-evaluation if the uncertainty in the true evidence base was not fully appreciated when policies were made. The inability of case-mix adjustment methods to compensate for selection bias and our inability to identify non-randomised studies that are free of selection bias indicate that non-randomised studies should only be undertaken when RCTs are infeasible or unethical. Recommendations for further research include: applying the resampling methodology in other clinical areas to ascertain whether the biases described are typical; developing or refining existing quality assessment tools for non-randomised studies; investigating how quality assessments of non-randomised studies can be incorporated into reviews and the implications of individual quality features for interpretation of a review's results; examination of the reasons for the apparent failure of case-mix adjustment methods; and further evaluation of the role of the propensity score.

The nucleic acid sequence bank now contains over 600 protein coding genes of which 107 are from prokaryotic organisms. Codon frequencies in each new prokaryotic gene are given. Analysis of genetic code usage in the 83 sequenced genes of the Escherichia coli genome (chromosome, transposons and plasmids) is presented, taking into account new data on gene expressivity and regulation as well as iso-tRNA specificity and cellular concentration. The codon composition of each gene is summarized using two indexes: one is based on the differential usage of iso-tRNA species during gene translation, the other on choice between Cytosine and Uracil for third base. A strong relationship between codon composition and mRNA expressivity is confirmed, even for genes transcribed in the same operon. The influence of codon use of peptide elongation rate and protein yield is discussed. Finally, the evolutionary aspect of codon selection in mRNA sequences is studied.

Despite their name, synonymous mutations have significant consequences for cellular processes in all taxa. As a result, an understanding of codon bias is central to fields as diverse as molecular evolution and biotechnology. Although recent advances in sequencing and synthetic biology have helped to resolve longstanding questions about codon bias, they have also uncovered striking patterns that suggest new hypotheses about protein synthesis. Ongoing work to quantify the dynamics of initiation and elongation is as important for understanding natural synonymous variation as it is for designing transgenes in applied contexts.

Functional interactions between T and B lymphocytes are necessary for optimal activation of an immune response. Recently, the T lymphocyte receptor CD28 was shown to bind the B7 counter-receptor on activated B lymphocytes, and subsequently to costimulate interleukin 2 production and T cell proliferation. CTLA-4 is a predicted membrane receptor from cytotoxic T cells that is homologous to CD28 and whose gene maps to the same chromosomal band as the gene for CD28. It is not known, however, if CD28 and CTLA-4 also share functional properties. To investigate functional properties of CTLA-4, we have produced a soluble genetic fusion between the extracellular domain of CTLA-4 and an immunoglobulin C gamma chain. Here, we show that the fusion protein encoded by this construct, CTLA4Ig, bound specifically to B7-transfected Chinese hamster ovary cells and to lymphoblastoid cells. CTLA4Ig also immunoprecipitated B7 from cell surface 125I-labeled extracts of these cells. The avidity of 125I-labeled B7Ig fusion protein for immobilized CTLA4Ig was estimated (Kd approximately 12 nM). Finally, we show that CTLA4Ig was a potent inhibitor of in vitro immune responses dependent upon cellular interactions between T and B lymphocytes. These findings provide direct evidence that, like its structural homologue CD28, CTLA-4 is able to bind the B7 counter-receptor on activated B cells. Lymphocyte interactions involving the B7 counter-receptor are functionally important for alloantigen responses in vitro.

The determine the effect of different foods on the blood glucose, 62 commonly eaten foods and sugars were fed individually to groups of 5 to 10 healthy fasting volunteers. Blood glucose levels were measured over 2 h, and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose. The largest rises were seen with vegetables (70 +/- 5%), followed by breakfast cereals (65 +/- 5%), cereals and biscuits (60 +/- 3%), fruit (50 +/- 5%), dairy products (35 +/- 1%), and dried legumes (31 +/- 3%). A significant negative relationship was seen between fat (p less than 0.01) and protein (p less than 0.001) and postprandial glucose rise but not with fiber or sugar content.

A systematic method for clinical description and classification of both normal and abnormal personality variants is proposed based on a general biosocial theory of personality. Three dimensions of personality are defined in terms of the basic stimulus-response characteristics of novelty seeking, harm avoidance, and reward dependence. The possible underlying genetic and neuroanatomical bases of observed variation in these dimensions are reviewed and considered in relation to adaptive responses to environmental challenge. The functional interaction of these dimensions leads to integrated patterns of differential response to novelty, punishment, and reward. The possible tridimensional combinations of extreme (high or low) variants on these basic stimulus-response characteristics correspond closely to traditional descriptions of personality disorders. This reconciles dimensional and categorical approaches to personality description. It also implies that the underlying structure of normal adaptive traits is the same as that of maladaptive personality traits, except for schizotypal and paranoid disorders.

This paper describes the statistical similarities among mediation, confounding, and suppression. Each is quantified by measuring the change in the relationship between an independent and a dependent variable after adding a third variable to the analysis. Mediation and confounding are identical statistically and can be distinguished only on conceptual grounds. Methods to determine the confidence intervals for confounding and suppression effects are proposed based on methods developed for mediated effects. Although the statistical estimation of effects and standard errors is the same, there are important conceptual differences among the three types of effects.

Comprehensive human genetic maps were constructed on the basis of nearly 1 million genotypes from eight CEPH families; they incorporated >8,000 short tandem-repeat polymorphisms (STRPs), primarily from Généthon, the Cooperative Human Linkage Center, the Utah Marker Development Group, and the Marshfield Medical Research Foundation. As part of the map building process, 0.08% of the genotypes that resulted in tight double recombinants and that largely, if not entirely, represent genotyping errors, mutations, or gene-conversion events were removed. The total female, male, and sex-averaged lengths of the final maps were 44, 27, and 35 morgans, respectively. Numerous (267) sets of STRPs were identified that represented the exact same loci yet were developed independently and had different primer pairs. The distributions of the total number of recombination events per gamete, among the eight mothers of the CEPH families, were significantly different, and this variation was not due to maternal age. The female:male ratio of genetic distance varied across individual chromosomes in a remarkably consistent fashion, with peaks at the centromeres of all metacentric chromosomes. The new linkage maps plus much additional information, including a query system for use in the construction of reliably ordered maps for selected subsets of markers, are available from the Marshfield Website.