Variance components for bovine tuberculosis infection and multi-breed genome-wide association analysis using imputed whole genome sequence data.

Bovine tuberculosis (bTB) is an infectious disease of cattle generally caused by Mycobacterium bovis, a bacterium that can elicit disease humans. Since the 1950s, the objective of the national bTB eradication program in Republic of Ireland was the biological extinction of bTB; that purpose has yet to be achieved. Objectives of the present study were to develop the statistical methodology and variance components to undertake routine genetic evaluations for resistance to bTB; also of interest was the detection of regions of the bovine genome putatively associated with bTB infection in dairy and beef breeds. The novelty of the present study, in terms of research on bTB infection, was the use of beef breeds in the genome-wide association and the utilization of imputed whole genome sequence data. Phenotypic bTB data on 781,270 animals together with imputed whole genome sequence data on 7,346 of these animals' sires were available. Linear mixed models were used to quantify variance components for bTB and EBVs were validated. Within-breed and multi-breed genome-wide associations were undertaken using a single-SNP regression approach. The estimated genetic standard deviation (0.09), heritability (0.12), and repeatability (0.30) substantiate that genetic selection help to eradicate bTB. The multi-breed genome-wide association analysis identified 38 SNPs and 64 QTL regions associated with bTB infection; two QTL regions (both on BTA23) identified in the multi-breed analysis overlapped with the within-breed analyses of Charolais, Limousin, and Holstein-Friesian. Results from the association analysis, coupled with previous studies, suggest bTB is controlled by an infinitely large number of loci, each having a small effect. The methodology and results from the present study will be used to develop national genetic evaluations for bTB in the Republic of Ireland. In addition, results can also be used to help uncover the biological architecture underlying resistance to bTB infection in cattle.

Sensitizing acute myeloid leukemia cells to induced differentiation by inhibiting the RIP1/RIP3 pathway.

Tumor necrosis factor-α (TNF-α)-induced RIP1/RIP3 (receptor-interacting protein kinase 1/receptor-interacting protein kinase 3)-mediated necroptosis has been proposed as an alternative strategy for treating apoptosis-resistant leukemia. However, we found that most acute myeloid leukemia (AML) cells, especially M4 and M5 subtypes, produce TNF and show basal level activation of RIP1/RIP3/MLKL signaling, yet do not undergo necroptosis. TNF, through RIP1/RIP3 signaling, prevents degradation of SOCS1, a key negative regulator of interferon-γ (IFN-γ) signaling. Using both pharmacologic and genetic assays, we show here that inactivation of RIP1/RIP3 resulted in reduction of SOCS1 protein levels and partial differentiation of AML cells. AML cells with inactivated RIP1/RIP3 signaling show increased sensitivity to IFN-γ-induced differentiation. RIP1/RIP3 inactivation combined with IFN-γ treatment significantly attenuated the clonogenic capacity of both primary AML cells and AML cell lines. This combination treatment also compromised the leukemogenic ability of murine AML cells in vivo. Our studies suggest that inhibition of RIP1/RIP3-mediated necroptotic signaling might be a novel strategy for the treatment of AML when combined with other differentiation inducers.

Improved survival in matched unrelated donor transplant for childhood ALL since the introduction of high-resolution matching at HLA class I and II.

We present the first detailed study analysing OS in BMT for paediatric ALL following the introduction of high-resolution (HR) HLA matching. A total of 356 consecutive paediatric ALL stem cell transplants performed between 1988 and 2007 were reviewed; 80 of them were performed following the introduction of HR HLA class I and class II matching to the transplant programme in 2002. Comparisons of matched unrelated donor (MUD) transplant outcomes before and after this period were made. Matching at the HR level for HLA-A, -B, -C, -DRB1 and -DQB1 (HR-MUD) correlated with a greater than 25% improvement in 2- and 5-year OS in paediatric ALL patients transplanted with MUDs (P=0.009, P=0.005, respectively). Two-year OS for contemporaneous HLA-matched sibling transplants (80.8%) and HR-MUD transplants (78.8%) was equivalent. At 6%, non-relapse mortality (NRM) in MUD transplants since 2002 was significantly reduced compared with previous epochs. Changes in treatment and epoch-dependent improvements in outcome were reviewed for possible confounders to the influence of HR typing using univariate and multivariate analysis.

Differential requirements for c-Myc in chronic hematopoietic hyperplasia and acute hematopoietic malignancies in Pten-null mice.

Myeloproliferative disorders (MPDs), lymphoproliferative disorders (LPDs), acute T-lymphocytic or myeloid leukemia and T-lymphocytic lymphoma were developed in inducible Pten (phosphatase and tensin homolog, deleted on chromosome ten)-knockout mice (Pten(-/-)). The appearance of these multiple diseases in one animal model provides an opportunity to study the pathogenesis of multiple diseases simultaneously. To study whether Myc function is required for the development of these hematopoietic disorders in Pten(-/-) mice, we generated inducible Pten/Myc double-knockout mice (Pten(-/-)/Myc(-/-)). By comparing the hematopoietic phenotypes of these double-knockout mice with those of Pten(-/-) mice, we found that both sets of animals developed MPDs and LPDs. However, none of the compound-mutant mice developed acute leukemia or lymphoma. Interestingly, in contrast to the MPDs that developed in Pten(-/-) mice, which are dominated by granulocytes, megakaryocytes predominate in the MPDs of Pten(-/-)/Myc(-/-) mice. Our study suggests that the deregulation of phosphoinositide 3-kinase/Akt signaling in Pten(-/-) hematopoietic cells protects these cells from apoptotic cell death, resulting in chronic proliferative disorders. However, owing to the differential requirement for Myc in granulocyte as compared to megakaryocyte proliferation, Myc deletion converts Pten(-/-) MPDs from granulocyte- to megakaryocyte-dominated conditions. Myc is absolutely required for the development of acute hematopoietic malignancies.

Genetics of human taste perception.

Genetic approaches are rapidly yielding new information about our sense of taste. This information comes from both molecular studies of genes encoding taste receptors and other taste-signaling components, and from studies of inherited variation in taste abilities. Our understanding of bitter taste has advanced by combined information from discovery and study of the TAS2R family of taste receptor genes, hand in hand with genetic linkage and positional cloning studies, notably on the ability to taste phenylthiocarbamide (PTC). Sweet and umami tastes, mediated by TAS1R receptors, are becoming well-characterized at the molecular genetic level, and these taste classes are now targets for linkage, positional cloning, and genetic association strategies. Salty and sour tastes are still poorly characterized in genetic terms, and represent opportunities for the future.

Relationship of papillae number to bitter intensity of quinine and PROP within and between individuals.

Subjects were asked to assess the bitterness of one 6-n-propyl-2-thiouracil (PROP) and two quinine HCl (QHCl) concentrations presented via filter papers of varying sizes. The number of taste papillae stimulated by these filter papers was counted in each individual. Whole mouth sensitivity to PROP was determined in a separate session. In support of other demonstrations of spatial summation, these data indicated that perceived bitterness intensity increased as a function of area of stimulation within subjects. Between subjects, there was a significant trend for the perceived bitterness of PROP to increase with the lingual density of fungiform papillae, although this trend was highly variable and was only demonstrable among those who showed at least moderate sensitivity to PROP. On the other hand, the number of stimulated fungiform papillae failed to account for individual differences in perceived bitterness of QHCl.

Effectiveness of surveillance of infrainguinal grafts.

OBJECTIVE: To audit the surveillance programme of infrainguinal vein graft in a tertiary vascular unit, and find out how effective it was in preventing occlusion of grafts. DESIGN: Retrospective study. SETTING: Teaching hospital, Scotland. SUBJECTS: 59 consecutive patients who had 61 vein grafts between 1996 and 1998 for critical limb ischaemia. INTERVENTIONS: Grafts scanned at 3-monthly intervals for at least a year, and clinical review. MAIN OUTCOME MEASURES: Survival with an intact limb and patency of the graft. RESULTS: 52 of the 59 patients (90%) were alive at the time of follow up, and 55 of the 61 involved limbs (90%) were intact. Median follow up was 660 days (range 180-1995). 23 stenoses were detected by the surveillance programme. 17 grafts were revised, all of which were patent at follow up, and 8 other grafts occluded requiring 6 major amputations. One-year cumulative primary, primary-assisted, and secondary patency, and limb salvage rates were 63%, 88%, 88%, and 90% respectively. CONCLUSIONS: Surveillance of infrainguinal grafts by duplex scanning is effective and has resulted in high rates of limb salvage and secondary patency in patients who presented with critical ischaemia.

Are human taste thresholds similar on the right and left sides of the tongue?

The human tongue is a relatively symmetrical anatomical structure and is generally assumed functionally equivalent on both sides. Experimental evaluation of this assumption is complicated by the fact that psychophysical measurements tend to vary considerably across testing sessions. To address functional laterality, we determined the detection thresholds of six right-handed and six left-handed subjects for Na saccharin, NaCl, citric acid and quinine HCl. Five pairs of interwoven, left and right unilateral thresholds were obtained for each taste stimulus in 12 subjects (n = 480 separate thresholds). In most cases mean sensitivity based on multiple measurements was found to be laterally symmetrical, however, we observed a few cases of lateral asymmetry of both general and compound-specific sensitivity. Threshold values were found to vary considerably across sessions, consistent with the test-retest variability previously reported for whole mouth thresholds. We conclude that taste threshold sensitivity is equivalent on the left and right anterior tongue for most individuals. Given the occasional exceptions to this rule, however, it is advisable to employ a counterbalanced design for any experimental or clinical testing protocol in which treatments are applied asymmetrically to the tongue.

Covariation in individuals' sensitivities to bitter compounds: evidence supporting multiple receptor/transduction mechanisms.

People vary widely in their sensitivities to bitter compounds, but the intercorrelation of these sensitivities is unknown. Our goal was to investigate correlations as a function of individual sensitivities to several bitter compounds representative of different chemical classes and, from these correlations, infer the number and variety of potential bitterness transduction systems for these compounds. Twenty-six subjects rated and ranked quinine HCl, caffeine, (-)-epicatechin, tetralone, L-phenylalanine, L-tryptophan, magnesium sulfate, urea, sucrose octaacetate (SOA), denatonium benzoate, and n-propylthiouracil (PROP) for bitterness. By examining individual differences, ratings and rankings could be grouped into two general clusters--urea/phenylalanine/tryptophan/epicatechin, and quinine/caffeine/SOA/denatonium benzoate/tetralone/magnesium sulfate-none of which contained PROP. When subjects were grouped into the extremes of sensitivity to PROP, a significant difference was found in the bitterness ratings, but not in the rankings. Therefore, there are also subjects who possess diminished absolute sensitivity to bitter stimuli but do not differ from other subjects in their relative sensitivities to these compounds.

Reduction of saltiness and bitterness after a chlorhexidine rinse.

Chronic rinsing with chlorhexidine, an oral-antiseptic, has been shown to decrease the saltiness of NaCl and the bitterness of quinine. The effect of acute chlorhexidine on taste has not been investigated. The purpose of the present study was to examine the effect of acute chlorhexidine rinses on taste intensity and quality of 11 stimuli representing sweet, salt, sour, bitter and savory. All stimuli were first matched for overall intensity so the effects of chlorhexidine would be directly comparable across compounds. As a control treatment, the bitter taste of chlorhexidine digluconate (0.12%) was matched in intensity to quinine HCl, which was found to cross-adapt the bitterness of chlorhexidine. Subjects participated in four experimental conditions: a pre-test, a quinine treatment, a chlorhexidine treatment, and a post-test condition, while rating total taste intensity and taste qualities in separate test sessions. Relative to the quinine treatment, chlorhexidine was found to decrease the salty taste of NaCl, KCl and NH4Cl, and not to significantly affect the tastes of sucrose, monosodium glutamate (MSG), citric acid, HCl and the taste of water. The bitter taste of urea, sucrose octa-acetate and quinine were suppressed after chlorhexidine rinses relative to water rinses, but were only marginally suppressed relative to quinine rinses. Potential mechanisms are discussed.

Ibuprofen as a chemesthetic stimulus: evidence of a novel mechanism of throat irritation.

This paper reports a study of the oral and pharyngeal chemesthetic effects of the non-steroidal anti-inflammatory drug (NSAID) ibuprofen [2-(4-isobutylphenyl)propanoic acid], which pilot experiments had indicated produces an unusual sensory irritation of the throat. In experiment 1 subjects swallowed aqueous solutions of ibuprofen prepared with different buffering agents and gave ratings of irritation and taste in the mouth and throat. The results showed that ibuprofen irritates the throat much more than the mouth, and that its quality in the throat is characterized primarily as sting/prick, itch and tickle (often leading to cough). Based upon the results obtained with the different buffering agents, we hypothesized that the sting/prick/itch qualities of throat irritation were pH-dependent. Parametric manipulation of solution pH in experiment 2 confirmed this hypothesis. The same experiment revealed that, in contrast to other oral irritants (e.g. capsaicin and menthol), repeated stimulation caused neither sensitization nor desensitization of throat irritation. In the final experiment we found that ibuprofen's throat irritation could not be modulated by temperature, as it should be if stimulation occurred via capsaicin-sensitive receptors. We therefore conclude that ibuprofen has novel chemesthetic properties, which are not mediated by capsaicin-sensitive (vanilloid) receptors, and that a major component of the throat irritation it produces occurs via a pH-dependent receptor mechanism.

A behavioral analysis of the ingestion of glucose, maltose and maltooligosaccharide by rats.

Glucose, maltose, and Polycose are stimuli that differ in their effectiveness in stimulating ingestion in the rat. To understand better how variation in glucose chain length affects the ingestion of these compounds, we compared the effect of six concentrations of glucose, maltose, and maltooligosaccharide (MOS) on the microstructure of the licking behavior of the rat. At the three lowest concentrations the order of effectiveness in stimulating ingestion was MOS > maltose > glucose. At the three highest concentrations, there were no differences among the three compounds in volume ingested. As measured by initial rate of licking, the orosensory stimulating effectiveness of the three compounds were ordered as MOS > maltose > glucose. The magnitude of the negative feedback signals were very similar for MOS and maltose and greater than glucose at all but the highest two concentrations of glucose, suggesting that glucose chain length, not caloric density, is responsible for the differences in the magnitude of negative feedback. With the three lowest concentrations, the ordering of the compounds in their ability to stimulate intake depended on orosensory stimulating ability.

Psychophysics of taste lateralization on anterior tongue.

There have been very few investigations of the spatial properties of taste stimuli localized to specific areas of the oral cavity. This is surprising, since the spatial localization of taste sensations may contribute to the overall taste percept, much as do quality, intensity, and the temporal characteristics of tastes. The difficulty in eliminating the confounding factor of a tactile sensation may partially account for the paucity of such studies, since a gustatory stimulus cannot be presented as a liquid without a tactile component. As a step toward understanding the localizability of gustatory sensations, we designed a yoked stimulator and an experimental procedure to control for tactile cues. Lateral discrimination was evaluated at the tip of the tongue with four taste stimuli (sodium saccharin, sodium chloride, citric acid, and quinine hydrochloride) by presenting a taste and a blank solution simultaneously at two locations on the tongue. We found that subjects could lateralize all four taste stimuli in the absence of any discriminative tactile cues. Subjects' ability to lateralize varied as a psychometric function of the stimulus concentration. Detection thresholds, measured in a forced-choice two-interval staircase procedure with the same yoked stimulator that was used in the lateralization task, were always lower than lateralization thresholds, and both lateralization and detection thresholds were correlated within subjects. Subjects were unable to lateralize taste cues on a nongustatory surface under the upper lip at the highest tested concentrations, at which performance was 100% on a gustatory surface (dorsal anterior tongue). These results show that (1) taste compounds can be lateralized in the absence of any discriminative mechanical cue (but only on the gustatory epithelium) and (2) although the localization of a compound does not logically require conscious detection of the taste (cf. blind sight), subjects always detected a taste when they were able to lateralize.

Selective removal of a target stimulus localized by taste in humans.

Recent studies have shown that people can localize a punctate gustatory stimulus on the lingual epithelium in the absence of discriminative tactile cues. The present studies examined the human ability to localize taste sensations on the tongue and to use this information to remove selectively a target stimulus (a flavored, 1 cm(3) gelatin cube) from the mouth when presented with non-target distractors that vary in number and taste. Findings indicate that humans are capable of localizing and removing either an aversive or an appetitive gustatory target from a field of tactile distractors via taste sensations alone, although this ability diminishes as the number of distractors increases (implicating serial searches, rather than parallel). In addition, humans can localize and selectively remove a target taste in the presence of distractors of another distinct taste quality. Under these conditions performance is either unaffected or reduced, which indicates that contrast with the distinct taste of the distractors does not enhance performance. Humans also are capable of removing a nearly tasteless cube from a field of flavored distractors, but this is clearly a more difficult task, suggesting that 'tactile capture' of taste occurs for the tasteless target cube and interferes with the localization of taste. Finally, perceived suprathreshold stimulus intensity did not seem to be related to the ability to localize and remove a target stimulus via taste sensations and failed to account for variations in performance across individuals.

Saccharin increases the effectiveness of glucose in stimulating ingestion in rats but has little effect on negative feedback.

To determine if oropharyngeal stimulation contributes to the magnitude of the negative feedback signal during ingestion, we tested rats on a series of solutions that varied in taste intensity but not in nutritive or osmotic properties. To do this, Na saccharin was added to a standard 0.2 M glucose solution in concentrations of 0, 0.25, 0.5, 1, 2, 4, and 8 mM. Nondeprived rats were given free access to these solutions in ascending order of concentration in 30-min tests in test cages with a lickometer that recorded the time of each lick to the nearest msec. The cumulative licking curve for each rat on each test, obtained by cumulating the number of licks in each successive minute during the test, was fit by the least squares method to an exponential function. This provides an estimate of the initial rate of licking and of the rate of decline in the rate of licking. The results were that the volume ingested increased from 6 to 26 ml and the initial rate of licking increased from 50 to 230 licks/min/min over the saccharin concentration range, but the estimates of the rate of decline of the rate of licking remained constant at about 0.06 licks/min over this range. Thus, we found no evidence for an oropharyngeal contribution to the decline in the rate of licking. Changes in the volume ingested depended solely on the initial avidity with which the rats ingested the solution.

Monogeusia for fructose, glucose, sucrose, and maltose.

We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations < or = 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with the monochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugars monogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.