How do referees visually explore? An in-situ examination of the referential head and eye movements of football referees.

The majority of a football referee's time is spent assessing open-play situations, yet little is known about how referees search for information during this uninterrupted play. The aim of the current study was to examine the exploratory gaze behaviour of elite and sub-elite football referees in open-play game situations. Four elite (i.e. national) and eight sub-elite (i.e. regional) referees officiated an in-situ football match while wearing a mobile eye-tracker to assess their gaze behaviour. Both referential head and eye movements (i.e. moving gaze away from and then back to the ball) were measured. Results showed gaze behaviour was characterised overall by more referential head than eye movements (~75 vs 25%), which were of longer duration (~950 vs 460 ms). Moreover, elite referees employed faster referential movements (~640 vs 730 ms), spending less time with their gaze away from the ball (carrier) than the sub-elite referees. Crucially, both the referential head and eye movements were coordinated relative to key events in the match, in this case passes, showing that referees anticipate the passes to ensure that the referential movements did not occur during passes, rather before or after. The results further our understanding of the coordinative gaze behaviours that underpin expertise in officiating.

CYP3A4 genotype is associated with sildenafil concentrations in patients with heart failure with preserved ejection fraction.

Despite its established inter-individual variability, sildenafil has been the subject of only a few pharmacogenetic investigations, with limited data regarding the genetic modulators of its pharmacokinetics. We conducted a pharmacogenetic sub-study of patients randomized to sildenafil (n=85) in the RELAX trial, which investigated the impact of high-dose sildenafil in patients with heart failure with preserved left ventricular ejection fraction (HFpEF). In the overall population, the CYP3A4 inferred phenotype appeared associated with the dose-adjusted peak concentrations of sildenafil at week 12 and week 24 (adjusted P=0.045 for repeated measures analysis), although this P-value did not meet our corrected significance threshold of 0.0167. In the more homogeneous Caucasian subgroup, this association was significant (adjusted P=0.0165 for repeated measures). Hence, CYP3A4 inferred phenotype is associated with peak sildenafil dose-adjusted concentrations in patients with HFpEF receiving high doses of sildenafil. The clinical impact of this association requires further investigation.

A pharmacogenetic investigation of intravenous furosemide in decompensated heart failure: a meta-analysis of three clinical trials.

We conducted a meta-analysis of pharmacogenomic substudies of three randomized trials conducted in patients with decompensated heart failure (HF) that were led by National Heart Lung and Blood Institute (NHLBI)-funded HF Network to test the hypothesis that candidate genes modulate net fluid loss and weight change in patients with decompensated HF treated with a furosemide-based diuretic regimen. Although none of the genetic variants previously shown to modulate the effects of loop diuretics in healthy individuals were associated with net fluid loss after 72 h of treatment, a set of rare variants in the APOL1 gene, which codes for apolipoprotein L1 (P=0.0005 in the random effects model), was associated with this end point. Moreover, a common variant in the multidrug resistance protein-4 coding gene (ABCC4, rs17268282) was associated with weight loss with furosemide use (P=0.0001). Our results suggest that both common and rare genetic variants modulate the response to a furosemide-based diuretic regimen in patients with decompensated HF.

Expert consensus statement to guide the evidence-based classification of Paralympic athletes with vision impairment: a Delphi study.

BACKGROUND: Paralympic sports are required to develop evidence-based systems that allocate athletes into 'classes' on the basis of the impact of their impairment on sport performance. However, sports for athletes with vision impairment (VI) classify athletes solely based on the WHO criteria for low vision and blindness. One key barrier to evidence-based classification is the absence of guidance on how to address classification issues unique to VI sport. The aim of this study was to reach expert consensus on how issues specific to VI sport should be addressed in evidence-based classification. METHOD: A four-round Delphi study was conducted with 25 participants who had expertise as a coach, athlete, classifier and/or administrator in Paralympic sport for VI athletes. RESULTS: The experts agreed that the current method of classification does not fulfil the requirements of Paralympic classification, and that the system should be different for each sport to account for the sports' unique visual demands. Instead of relying only on tests of visual acuity and visual field, the panel agreed that additional tests are required to better account for the impact of impairment on sport performance. There was strong agreement that all athletes should not be required to wear a blindfold as a means of equalising the impairment during competition. CONCLUSIONS: There is strong support within the Paralympic movement to change the way that VI athletes are classified. This consensus statement provides clear guidance on how the most important issues specific to VI should be addressed, removing key barriers to the development of evidence-based classification.

"What needs to be seen": An exploration into the visual anticipation behaviour of different skill-level football referees while observing long passes on-field.

It is well established that elite football referees possess superior anticipatory skills in specific game scenarios such as when assessing foul situations. Referees might also have better anticipatory skills in other important scenarios such as when observing a long pass. In these often-occurring situations, a referee has to use visual information to anticipate the outcome of the pass, in particular to foresee any potential infringements that might occur when players battle for ball possession. However, little is known about if and how football referees might anticipate outcomes in these scenarios. The aim of the current study was therefore to analyse the visual anticipatory behaviour of football referees when long passes occur during actual football matches. Elite (N = 4) and sub-elite referees (N = 12) officiated an actual football match while wearing a mobile eye-tracker to analyse their gaze behaviour when long passes occurred (N = 196). The results revealed differences in the way that the elite and sub-elite referees tracked the ball and anticipated the outcome of the ball trajectories. The elite referees used a lower search rate (1.3 vs 1.8 fix/s; p < .05) and were more likely to direct their gaze towards the ball during the moment of kick (77 vs 52%; p < .05) and the early flight-phase of the pass (68 vs 45%; p < .05), and subsequently produced earlier anticipatory eye movements to the player(s) receiving the ball (at 50% vs 60% of the ball flight; p < .05). This earlier anticipation may help the elite referees to better pick-up relevant information about the receivers that could be vital in making adjudications about any potential infringement when the ball does arrive. Referee education programs can use the current study to highlight the importance of visual search behaviour and help referees to adapt a strategy that is beneficial for long-pass situations.

Influence of combinations of human major histocompatibility complex genes on the course of HIV-1 infection.

Major histocompatibility complex (MHC) genes (HLA in humans) regulate the immune response to foreign antigens. Molecular and serologic techniques were used to identify products of HLA class I, class II and transporter (TAP) genes (also part of the MHC) in homosexual seroconverters to human immunodeficiency virus type 1 (HIV-1). Comprehensive statistical analysis produced an HLA profile that predicted time from HIV-1 infection to the onset of AIDS. The profile was developed in a cohort of 139 men and evaluated in a second unrelated cohort of 102 men. In the evaluation cohort, the profile discriminated a sixfold difference between groups with the shortest and longest times to AIDS (P = 0.001). These findings support current theory about control of antigen processing by HLA genes and have implications for immunopathogenesis of HIV-1 and other infections.

Participation of suppressor T cells in the immunosuppressive activity of a heteroantiserum to human Ia-like antigens (p23,30).

We studied the effects of an antiserum to human Ia-like antigens (p23,30) upon the polyclonal activation of normal B cells (cultured with various combination of irradiated and unirradiated T cells) to become immunoglobulin-secreting cells after stimulation with pokeweed mitogen in vitro. We found that the antiserum suppressed immunoglobulin production. The inhibitory effect did not appear to result from a simple interaction at the B-cell/monocyte level alone. Rather, the inhibitory effect required the presence of a radiosensitive subset of autologous suppressor T cells.

Detection of antigens specific for B-lymphoid cultured cell lines with human alloantisera.

Human sera were tested for cytotoxicity to pairs of long-term tissue-cultured cell lines. Each pair had been derived from the same individual and one of the pairs possessed the characteristics of either "T" or "B" cells. The alloantisera used were HL-A-typing reagents or sera obtained from Amish multiparas. Selected cytotoxicity was found against the B-cell lines by direct testing. Cytotoxicity was abolished by absorption with B-cell line but not by absorption with the T-cell lines. The results suggest that a group of allotypic antigens may be expressed exculsively on human B cells.

Configuration and expression of the T cell receptor beta chain gene in human T-lymphotrophic virus I-infected cells.

We studied the configuration and expression of the gene encoding the beta chain of the T cell receptor (TCR beta) in cell lines and primary tumor cells infected by the human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I). Most of the cell lines and all the primary tumor cells showed rearrangement of the TCR beta gene, and in each case the rearrangement was distinct. The majority of cases examined were clonal with respect to a particular TCR beta gene rearrangement. Primary tumor cells from one case (SD) were found to have a tandem duplication of a portion of chromosome 7; this appears to have resulted in the presence of three alleles of the TCR beta gene, each of which is arranged differently. This suggests that the chromosomal abnormality, and possibly infection by HTLV-I, occurred before TCR beta gene rearrangement. Cell lines infected by HTLV-I express levels of TCR beta mRNA similar to PHA stimulated lymphocytes, suggesting that this gene is not transcriptionally activated as a result of infection by HTLV-I. Cloned T cells of known antigen specificity that are infected by HTLV-I in vitro show impairment of immune function, including loss of antigen-specific responsiveness and the acquisition of alloreactivity. Comparison of the configuration of the TCR beta gene before and after infection revealed no changes detectable by Southern blot analysis. Levels of expression of the TCR beta gene at the mRNA level and surface expression of the T3 complex were also not significantly altered, suggesting that changes in immune function cannot be attributed to quantitative changes in the TCR molecule. The configuration of the TCR beta gene in primary tumor cells infected by HTLV-I was compared with that in the derived cell lines. In all pairs examined, the configuration in the primary tumor cells was different from that in the cell lines, strongly suggesting that the cells that grow in culture are not the original neoplastic cells.

Molecular definition of a polymorphic antigen (LA45) of free HLA-A and -B heavy chains found on the surfaces of activated B and T cells.

A monomoprhic monoclonal antibody (LA45 antibody) reactive with "a new activation-induced surface structure on human T lymphocytes" (LA45 antigen) that resembled free class I heavy chains has recently been described (Schnabl, E., H. Stockinger, O. Majdic, H. Gaugitsch, I.J.D. Lindley, D. Maurer, A. Hajek-Rosenmayr, and W. Knapp. 1990. J. Exp. Med. 171:1431). This antibody was used to clone a class I-like heavy chain (LA45 gene) from the HUT 102 tumor cell, which paradoxically did not give rise to the LA45 antigen on transfection into monkey COS cells. We show here that the LA45 gene is HLA-Aw66.2, a previously uncharacterized allele of the HLA-A locus. The previously determined LA45 sequence differs from that of HLA-Aw66.2, from HUT 102, and the CR-B B cell line derived from the same individual as HUT 102 by substitution of tryptophan for serine at position 4 in the alpha 1 domain. Transfection of HLA-Aw66.2, and of a mutant of this gene with serine 4 substituted for tryptophan, into a human B cell line (C1R) both resulted in expression of the LA45 epitope. Furthermore, we find expression of the LA45 epitope on Epstein Barr virus-transformed B cell lines as well as lectin-activated T cells, but not on long-term T cell lines or unstimulated peripheral blood T cells. The specificity of the LA45 antibody is polymorphic and the presence of the LA45 epitope is precisely correlated with the sequence arginine, asparagine (RN) at residues 62 and 63 of the helix of the alpha 1 domain. The LA45 epitope is broadly distributed, being associated with half the alleles of both HLA-A and -B loci but none of the HLA-C locus. All the results are consistent with the presence of pools of free HLA-A and -B heavy chains at the surfaces of certain cell types but not others. Such molecules are probably responsible for the HLA-associated class I alloantigens of lectin-activated T cells. We hypothesize the free heavy chains result from dissociation of beta 2-microglobulin from subpopulations of empty HLA-A,B molecules, or molecules with weakly bound peptides, that vary in size depending on cellular activation and peptide supply.

Generation of an HLA-restricted cytotoxic T cell line reactive against cultured tumor cells from a patient infected with human T cell leukemia/lymphoma virus.

Lymphocytes from a patient who had an unusually long survival after therapy for a human T cell leukemia/lymphoma virus (HTLV)-associated T cell lymphoma were stimulated in vitro with an autologous tumor cell line, and the generation of cytotoxic T lymphocytes (CTL) was studied. CTL generated were directed against autologous (HTLV-associated tumor cells. These propagated CTL were OKT3+, OKT4-, and OKT8+. The cytotoxic activity required target tumor cells that were infected with HTLV and also expressed histocompatibility antigens in common with the patient, suggesting a major histocompatibility complex-restricted associative recognition of target antigens expressed on the tumor cell membrane.

Demonstration of a third structurally distinct human Ia beta chain by two-dimensional gel electrophoresis.

Previous studies have indicated that HLA-DR homozygous cell lines express two Ia alpha and Ia beta chains that combine to form at least two Ia molecules. This report demonstrates by two-dimensional gel electrophoresis the existence of a third structurally distinct human Ia beta chain on DR2 and DR5 cell lines. This suggests that at least five separate genes control the expression of Ia molecules on HLA-DR homozygous cell lines.

Isolation and immunologic characterization of a human. B-lymphocyte-specific, cell surface antigen.

In addition to HL-A antigens, another cell surface protein complex has been obtained from membranes of the human B-lymphoblast cell line IM-1. This complex which was solubilized with papain, consisted of polypeptides of 23,000 and 30,000 daltons (p23, 30). Rabbit antisera to this material precipitated from [35S]methionine-labeled detergent-solubilized cells, three proteins of 39,000, 34,000, and 29,000 daltons. These antisera were specifically cytotoxic for B lymphocytes of peripheral blood, for B-lymphoblast cell lines, and for EAC rosette receptor-positive surface Ig-negative (Null) lymphocytes. The p23,30 complex was not present on T lymphocytes, EAC rosette receptor-negative Null lymphocytes, or platelets. In addition, the p23,30 complex from several cell lines inhibited alloantisera from multiparous Amish women which had been shown to recognize non-HL-A, B-lymphocyte antigens. Some other properties of the anti-p23,30 sera antisera were described.

Th17/Tc17 infiltration and associated cytokine gene expression in elicitation phase of allergic contact dermatitis.

BACKGROUND: Allergic contact dermatitis (ACD) is a typical delayed-type hypersensitivity to sensitizing haptens mediated by T cells. Th1/Tc1 cells are currently considered to be the primary effectors in ACD. There is little information concerning the role played in ACD in humans by Th17/Tc17 cells, a recently defined subpopulation of effector T cells. OBJECTIVES: In the present report we attempted to characterize Th17/Tc17 cells in the infiltrates of the skin in the elicitation phase of ACD. METHODS: Th17 as well as Th1/Th2 cytokine gene expression was examined by semiquantitative real-time polymerase chain reaction in paired samples of positive patch test biopsies and normal skin from 11 patients allergic to nine different allergens. The in situ characterization of interleukin (IL)-17-producing cells was carried out using anti-RORC and anti-T-cell subset antibodies by double immunofluorescence. RESULTS: Compared with normal paired skin samples, gene expression of transcription factor for human Th17 cells, RORC, and Th17-related cytokines IL-17A, IL-17F and IL-23 was significantly increased in positive patch test biopsies. The mRNA for interferon-gamma and IL-4 was also increased. In the dermal infiltrates, about 20% of the infiltrating cells were IL-17-producing cells as they expressed RORC, and such RORC-expressing cells were detected in both CD4+ (approximately 30%) and CD8+ (approximately 20%) subsets. CONCLUSIONS: This is the first demonstration of Th17/Tc17 cells in the elicitation phase of human ACD, showing that they are a regular participant in the immunopathology of this common allergic reaction regardless of the nature of the triggering allergen.

Detection of an antigen associated with acute leukemia.

Antiserums to a purified cell membrane component from a Burkitt's lymphoma tissue culture cell line were produced in rabbits. These antiserums were cytotoxic to peripheral white blood cells from 8 of 15 patients with acute leukemia and 5 of 41 relatives, but not to peripheral white blood cells from leukemia patients in clinical remission or from normal individuals. These antiserums appear to be detecting an acute leukemia associated antigen or antigens.

B lymphocyte antigens in sicca syndrome.

All individuals tested in this study with sicca syndrome, a human autoimmune disease, bear two immunologically distinct and genetically unrelated B lymphocyte antigens that appear similar to the immune response associated (Ia) antigens of the mouse. The genes coding for these two antigens are present in only 37 and 24 percent of normal controls. In animal models Ia antigen genes are closely linked to immune response genes. Our findings suggest that two such genes may be required for the development of sicca syndrome.

Molecular heterogeneity of human lymphoid (HL-A) alloantigens.

Soluble preparations of HL-A alloantigens were separated by gel filtration into components having either the "LA" series or the "4" series of alloantigenic determinants. This separation may indicate that several different structural cistrons within the HL-A (locus) control the expression of these two series of determinants. The alternative possibility, in which one structural cistron with multiple mutational sites controls the synthesis of a single molecule cannot be excluded.

HTLV-I--associated B-cell CLL: indirect role for retrovirus in leukemogenesis.

Serum containing antibodies to the human T-lymphotropic virus type I (HTLV-I) has been observed at a higher than expected frequency in patients with B-cell chronic lymphocytic leukemia (CLL) in an area endemic for HTLV-I. An attempt was made to determine whether the cells from patients with this leukemia were HTLV-I antigen-committed B cells that had undergone malignant transformation. Cells from two HTLV-I seropositive Jamaican patients with CLL were fused with a human B-lymphoblastoid cell line. The hybridoma cells that resulted from the fusion of CLL cells from patient I.C. produced an immunoglobulin (IgM) that reacted with the p24 gag protein from HTLV-I, HTLV-II, and HTLV-III (now referred to as HIV), but showed preferential reactivity with HTLV-I. The specific immunoglobulin gene rearrangement (IgM, kappa) in the CLL cell was demonstrated in the hybridoma cell line, indicating that the captured immunoglobulin was from the CLL cells. The IgM secreted by the fusion of CLL cells from patient L.L. reacted only with HTLV-I-infected cells and with the HTLV-I large envelope protein (gp61) on Western blots. The CLL cells from these patients appear to be a malignant transformation of an antigen-committed B cell responding to HTLV-I infection, suggesting an indirect role for this retrovirus in leukemogenesis.

Cellular proteins bound to immunodeficiency viruses: implications for pathogenesis and vaccines.

Cellular proteins associated with immunodeficiency viruses were identified by determination of the amino acid sequence of the proteins and peptides present in sucrose density gradient-purified human immunodeficiency virus (HIV)-1, HIV-2, and simian immunodeficiency virus (SIV). beta 2 microglobulin (beta 2m) and the alpha and beta chains of human lymphocyte antigen (HLA) DR were present in virus preparations at one-fifth the concentration of Gag on a molar basis. Antisera to HLA DR, beta 2 m, as well as HLA class I precipitated intact viral particles, suggesting that these cellular proteins were physically associated with the surface of the virus. Antisera to class I, beta 2m, and HLA DR also inhibited infection of cultured cells by both HIV-1 and SIV. The specific, selective association of these cellular proteins in a physiologically relevant manner has major implications for our understanding of the infection process and the pathogenesis of immunodeficiency viruses and should be considered in the design of vaccines.

In vitro lymphocyte proliferation response to therapeutic insulin components. Evidence for genetic control by the human major histocompatibility complex.

Genes in the major histocompatibility complex of mice and guinea pigs control immunologic responsiveness to insulins from other animal species. In order to determine if similar genetic control exists in man, we have examined lymphocyte proliferation responses to components of therapeutic insulins by employing lymphocytes from diabetic patients that receive insulin. Distinct groups of individuals demonstrated positive lymphocyte proliferative responses to beef insulin, beef and pork insulin, beef proinsulin, pork proinsulin, and protamine. Lymphocytes from the patient population were typed for the HLA-A, B, C, and DR antigens. An increased frequency of certain HLA antigens was found in those individuals that responded to the following therapeutic insulin components: beef, HLA-DR4; beef and pork, HLA-DR3; beef proinsulin, HLA-BW4, CW2, CW5, DR2, and DR5; protamine, HLA-CW3, CW5, and DR7. The results demonstrate that the human immune system recognized the structural differences between human and beef and/or pork insulin. These differences are two amino acids in the A chain, alpha loop, of beef insulin and the single terminal amino acid, alanine, which is common to pork and beef insulins. Positive responses to both beef proinsulin and pork proinsulin demonstrated the capability of restricted recognition of more complex proteins represented by the C-peptide in these insulin preparations. Lymphocyte proliferative responses to protamine were also restricted, which suggests a genetic control to this antigen. The association of these responses with HLA alloantigens strongly suggests that genes within the human major histocompatibility complex control recognition and lymphocyte response to therapeutic insulin components.