Understanding the CD28/CTLA-4 (CD152) pathway and its implications for costimulatory blockade

T cell activation is a key event in the adaptive immune system and vital in the generation of protective cellular and humoral immunity. Activation is required to generate CD4 effector T cell responses and provide help for B cell and cytotoxic T cell responses. While defective T responses to foreign antigen result in infectious pathology, over-reactive T cell responses against self-antigens result in autoimmunity and, in a transplantation setting, tissue rejection. Understanding how T cell activation is normally regulated is critical to therapeutic intervention and the CD28/CTLA-4 (CD152) pathway represents the initial activation checkpoint in molecular terms. In particular, while the CTLA-4 pathway is well established as an essential regulator of self-reactivity, its mechanism of action is still uncertain. Such mechanistic issues are important given its central position in T cell activation and the increasing number of therapeutic modalities aimed at manipulating the CD28/CTLA-4 pathway. Here, we provide an updated view of CTLA-4 biology, reviewing the established features of the system and highlighting its interplay with CD28. We then discuss how recent progress in our understanding of this pathway affects our interpretations following intervention.

Neonatal abstinence syndrome: transitioning methadone-treated infants from an inpatient to an outpatient setting

OBJECTIVE

Each year in the US ∼50 000 neonates receive inpatient pharmacotherapy for the treatment of neonatal abstinence syndrome (NAS). The objective of this study is to compare the safety and efficacy of a traditional inpatient only approach with a combined inpatient and outpatient methadone treatment program.

STUDY DESIGN

Retrospective review (2007 to 2009). Infants were born to mothers maintained on methadone in an antenatal substance abuse program. All infants received methadone for NAS treatment as inpatient. Methadone weaning for the traditional group (75 patients) was inpatient, whereas the combined group (46 patients) was outpatient.

RESULT

Infants in the traditional and combined groups were similar in demographics, obstetrical risk factors, birth weight, gestational age (GA) and the incidence of prematurity (34 and 31%). Hospital stay was shorter in the combined than in the traditional group (13 vs 25 days; P<0.01). Although the duration of treatment was longer for infants in the combined group (37 vs 21 days, P<0.01), the cumulative methadone dose was similar (3.6 vs 3.1 mg kg(-1), P=0.42). Follow-up information (at least 3 months) was available for 80% of infants in the traditional and 100% of infants in the combined group. All infants in the combined group were seen ≤72 h from hospital discharge. Breastfeeding was more common among infants in the combined group (24 vs 8% P<0.05). Following discharge there were no differences between the two groups in hospital readmissions for NAS. Prematurity (34 to 36 weeks GA) was the only predictor for hospital readmission for NAS in both groups (P=0.02, OR 5). Average hospital cost for each infant in the combined group was $13 817 less than in the traditional group.

CONCLUSION

A combined inpatient and outpatient methadone treatment in the management of NAS decreases hospital stay and substantially reduces cost. Additional studies are needed to evaluate the potential long-term benefits of the combined approach on infants and their families.

Measurement of an exceptionally weak electron-phonon coupling on the surface of the topological insulator Bi2Se3 using angle-resolved photoemission spectroscopy

Gapless surface states on topological insulators are protected from elastic scattering on nonmagnetic impurities which makes them promising candidates for low-power electronic applications. However, for widespread applications, these states should have to remain coherent at ambient temperatures. Here, we studied temperature dependence of the electronic structure and the scattering rates on the surface of a model topological insulator, Bi2Se3, by high-resolution angle-resolved photoemission spectroscopy. We found an extremely weak broadening of the topological surface state with temperature and no anomalies in the state's dispersion, indicating exceptionally weak electron-phonon coupling. Our results demonstrate that the topological surface state is protected not only from elastic scattering on impurities, but also from scattering on low-energy phonons, suggesting that topological insulators could serve as a basis for room-temperature electronic devices.

Photoemission spectroscopy of magnetic and nonmagnetic impurities on the surface of the Bi2Se3 topological insulator

Dirac-like surface states on surfaces of topological insulators have a chiral spin structure that suppresses backscattering and protects the coherence of these states in the presence of nonmagnetic scatterers. In contrast, magnetic scatterers should open the backscattering channel via the spin-flip processes and degrade the state's coherence. We present angle-resolved photoemission spectroscopy studies of the electronic structure and the scattering rates upon the adsorption of various magnetic and nonmagnetic impurities on the surface of Bi2Se3, a model topological insulator. We reveal a remarkable insensitivity of the topological surface state to both nonmagnetic and magnetic impurities in the low impurity concentration regime. Scattering channels open up with the emergence of hexagonal warping in the high-doping regime, irrespective of the impurity's magnetic moment.

Electronic structure of the topological insulator Bi2Se3 using angle-resolved photoemission spectroscopy: evidence for a nearly full surface spin polarization

We performed high-resolution spin- and angle-resolved photoemission spectroscopy studies of the electronic structure and the spin texture on the surface of Bi2Se3, a model TI. By tuning the photon energy, we found that the topological surface state is well separated from the bulk states in the vicinity of kz = Z plane of the bulk Brillouin zone. The spin-resolved measurements in that region indicate a very high degree of spin polarization of the surface state, ~0.75, much higher than previously reported. Our results demonstrate that the topological surface state on Bi2Se3 is highly spin polarized and that the dominant factors limiting the polarization are mainly extrinsic.

Diphasic postsynaptic potential: a chemical synapse capable of mediating conjoint excitation and inhibition

Two identified interneurons in each buccal ganglion of Aplysia can mediate conjoined excitation and inhibition to a single follower cell. A single presynaptic action potential in one of these interneurons produces a diphasic, depolarizing-hyperpolarizing synaptic potential apparently as a result of a single transmitter acting on two types of postsynaptic receptors in the follower cell. These receptors produce synaptic potentials with differing reversal potentials, ionic conductances, time courses, rates of decrement with repetition, pharmacological properties, and functional consequences. The excitatory receptor controls a sodium conductance, the inhibitory receptor controls a chloride conductance. Both components of the synaptic potentials can be produced by iontophoretic application of acetylcholine on the cell body of the follower cell, and each component is differentially sensitive to different cholinergic blocking agents.

Evaluation of anti-IL-6 monoclonal antibody therapy using murine type II collagen-induced arthritis

Interleukin-6 is a multifunctional cytokine that is critical for T/B-cell differentiation and maturation, immunoglobulin secretion, acute-phase protein production, and macrophage/monocyte functions. Extensive research into the biology of IL-6 has implicated IL-6 in the pathophysiology and pathogenesis of RA. An anti-murine IL-6 mAb that neutralizes mouse IL-6 activities was tested in animal model of collagen-induced arthritis. Prophylactic treatment with anti-IL-6 mAb significantly reduced the incidence and severity of arthritis compared to control mAb treated mice. The mitogenic response of B and T cells isolated from the lymph nodes of anti-IL-6 treated mice was significantly reduced compared to cells isolated from control mAb treated mice. The overall histopathology score for paws from the anti-IL-6 treated mice was significantly reduced when compared to paws from mice treated with control mAb, including both inflammatory (synovitis and pannus) and erosive (erosions and architecture) parameters. Reduced loss of cartilage matrix components was also observed in the anti-IL-6 treated mice. Collectively, these data suggest that IL-6 plays a major role in the pathophysiology of rheumatoid arthritis, and thus support the potential benefit of anti-IL-6 mAb treatment in rheumatoid arthritis patients.

Mimosa tenuiflora as a cause of malformations in ruminants in the northeastern Brazilian semiarid rangelands

Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs are common malformations seen in ruminants grazing semiarid rangelands of Northeastern Brazil. To investigate the cause of these malformations, we fed 2 suspected plants, Mimosa tenuiflora or Prosopis juliflora, to groups of 4 pregnant goats each. Fresh green M. tenuiflora was collected daily and fed ad libitum to 4 goats in group 1 throughout pregnancy. This treatment group also received a supplemental feed concentrate equivalent to 1% body weight. Four goats in group 2 received a ration with 70% of P. juliflora pods and 30% hay throughout pregnancy. Four control goats were fed supplemental feed concentrate (1% body weight) and hay ad libitum throughout pregnancy. Goats treated with P. juliflora pods and the control goats delivered 9 normal kids. The four goats that were fed M. tenuiflora during pregnancy delivered 4 kids, 3 of which had abnormalities similar to those observed in field cases, including cleft lip, unilateral corneal opacity, ocular bilateral dermoids, buphthalmos with a cloudy brownish appearance of the anterior chamber due to an iridal cyst, and segmental stenosis of the colon. Malformations induced experimentally by M. tenuiflora were similar to those observed in field cases, suggesting that M. tenuiflora is a cause of the field cases observed in the Brazilian semiarid rangelands.

The effects of indomethacin tocolysis on the postnatal response of the ductus arteriosus to indomethacin in extremely low birth weight infants

BACKGROUND

Antenal indomethacin reportedly decreases the responses of a symptomatic patent ductus arteriosus (sPDA) to postnatal indomethacin treatment. Whether a similar exposure affects the responses to indomethacin prophylaxis is unknown.

OBJECTIVE

To evaluate the clinical responsiveness of ductus arteriosus to indomethacin prophylaxis and to the treatment of sPDA in extremely low birth weight (ELBW) infants following indomethacin tocolysis.

METHODS

Retrospective cohort study of 58 ELBW infants whose mothers received indomethacin tocolysis (study) and 58 ELBW infants whose mothers did not (controls), matched by gender, gestational age (GA), birth weight and postnatal sPDA management (prophylaxis or early treatment).

RESULTS

Indomethacin was used as a tocolytic at a median dose of 250 mg, for a duration of 2 days, and ending 1 day before delivery. Study and control mothers were comparable in demographics, antenatal steroid use, cesarean delivery, but were different in the incidence of preeclampsia and preterm labor. Study and control infants were similar in birth weight, GA, indomethacin prophylaxis, early sPDA treatment, mortality, necrotizing enterocolitis, severe intraventricular hemorrhage and stage 3-5 retinopathy of prematurity. Seventeen of 43 study and 16 of 43 control infants who received indomethacin prophylaxis developed sPDA and were combined with early treatment sPDA infants (15 to each group). Two of 32 study and two of 31 control infants underwent surgical ligation whereas the remaining were treated with indomethacin. Sixteen of 30 (53%) and 13 of 29 (45%) were successfully treated and did not require ligation. Study infants were divided according to their mothers' indomethacin total dose (28 infants received <or=225 mg and 30 infants received >225 mg). Both subgroups were demographically and clinically comparable and their response to indomethacin prophylaxis and treatment were similar.

CONCLUSION

In ELBW infants, exposure to indomethacin tocolysis does not affect the clinical responsiveness of the ductus arteriosus to prophylaxis or that of the sPDA to indomethacin treatment.

123 CRYOPROTECTANT EXPOSURE AFFECTS THE PROTEOME OF THE MOUSE METAPHASE II OOCYTE

The ability to routinely cryopreserve oocytes will have a significant impact on human- and domestic animal-assisted reproduction, and on wildlife conservation. However, success with oocyte cryopreservation has been relatively limited. Previous studies have shown that slow freezing alters mouse oocyte physiology, including the proteome. To improve cryopreservation techniques, it is vital to investigate the effects of the cryopreservation procedure on oocyte physiology. It was therefore the aim of this study to determine at which stage of the slow freezing procedure the proteome was affected, or whether exposure to the cryoprotectant (1,2-propanediol; PrOH) alone was responsible for cellular perturbations. Metaphase II (MII) oocytes were collected from superovulated F1 (C57BL/6 x CBA) mice at 13 h post-hCG. Denuded MII oocytes were randomly allocated to treatments that mimic parts of the slow freezing protocol: (A) 37�C for 20 min (control), (B) room temperature for 20 min (temperature control), (C) 1.5 M PrOH exposure for 20 min (i.e. the equilibration and dehydration step), and (D) 1.5 M PrOH exposure and seeding (i.e. the equilibration, dehydration, and seeding step). Oocytes were then collected in groups of 5 (n = 12 replicates per group), extracted, processed, and analyzed by time-of-flight mass spectrometry. Statistical analysis was performed with the Mann-Whitney non-parametric test. Oocytes maintained at room temperature for 20 min displayed a protein profile similar to that of oocytes incubated at 37�C. The protein expression profile was altered when oocytes were exposed to PrOH for twenty min, with several proteins showing at least a two-fold change of expression level. A similar effect on protein expression was also observed with 20 min of PrOH exposure plus seeding. On comparison with control oocytes, those exposed to PrOH (with or without seeding) had a significantly (P &lt; 0.05) lower abundance of 6 proteins and up-regulation of 4 proteins. Analysis of the mouse MII oocyte at different stages of the slow freezing protocol revealed that there is negligible impact on protein expression when oocytes are maintained at room temperature for 20 min. However, PrOH exposure at room temperature for the same amount of time induces significant perturbation of the oocytes&apos; proteome. These data demonstrate that temperature changes per se (during cooling to room temperature and seeding) impact negligibly on the oocyte proteome, whereas exposure of oocytes to 1.5 M PrOH alone, which mimics the equilibration phase of slow freezing, significantly alters the proteome. The detrimental effect on the oocyte proteome suggests that chronic exposure to PrOH during slow freezing negatively impacts oocyte cryopreservation. To conclude, analyzing the effects of cryopreservation on cell physiology is pivotal for allowing the selection of appropriate techniques and implementing appropriate modifications. This study was supported by a grant from Vitrolife.

Isocupressic acid, an abortifacient component of Cupressus macrocarpa

Anecdotal reports suggest that abortion occurs in New Zealand cattle after ingestion of macrocarpa (Cupressus macrocarpa). The clinical signs observed are similar to those seen in abortions caused by ponderosa pine (Pinus ponderosa Laws). Isocupressic acid has been identified as an abortifacient component of the needles of ponderosa pine. Macrocarpa collected from the Palmerston North area contained 0.89% and 1.24% isocupressic acid, compared to 1.70% isocupressic acid in Ponderosa pine needles from Oregon in the United States as analysed by the USDA-ARS Poisonous Plant Research Laboratory. These findings support observations that macrocarpa causes abortion in late gestation cattle in New Zealand and suggest the causal agent is probably isocupressic acid.

Tinnitus and psychological morbidity: a cross-sectional study to investigate psychological morbidity in tinnitus patients and its relationship with severity of symptoms and illness perceptions

This study investigates the relationship between tinnitus and psychological morbidity using a cross-sectional survey design from patients of an outpatient audiology department in a typical District General Hospital. The results suggest that a significant number of tinnitus patients suffer from psychological problems both during and more unfortunately after routine treatment for their tinnitus. Anxiety was found to be the main psychological problem. In conclusion, this study suggests that, while further research is needed, many tinnitus patients require psychological treatment and this has implications for the staffing of audiology units in District General Hospitals.

135 REGULATION OF GLUCOSE METABOLISM TO DECREASE LIPID CONTENT OF IN VIRTO-PRODUCED BOVINE EMBRYOS

Our objective was to improve normality of embryos produced in vitro with regulators of carbohydrate metabolism at doses optimized in earlier experiments. Eight- to 16-cell embryos were produced in vitro in the G1/G2 system (chemically defined sequential medium with recombinant human serum albumin), and then cultured 3 days in G2 containing metabolic regulators as follows: phenazine ethosulfate (PES), 0.3 μM; NaN3, 27 μM; 2,4-dinitrophenol (DNP), 30 μM; and control. The following responses were analyzed by ANOVA in 2 to 4 replicates of 8–12 embryos each: glucose uptake and metabolism (uptake measured by microfluorometry of medium after incubating an embryo 3 h; metabolism measured as 3H2O released after incubating an embryo 3 h in medium containing 5-3H glucose), % of glucose metabolized via the pentose phosphate pathway (PPP rate), lactate production, glycolysis (% of lactate produced from glucose taken up on a molar basis), lipid accumulation (number of >2 μM Sudan Black B positive granules/103 μm2), % live Day 14 embryos recovered from embryos transferred to recipients at Day 7, and average surface area of embryos collected. In vivo-derived embryos were included as a second control for lipid evaluation. PES-treated embryos had higher glucose metabolism (P < 0.05) and lower glucose uptake (P < 0.01) than embryos in NaN3 and tended to have a higher PPP rate (P < 0.11) than controls; however, glycolysis was higher for PES than other treatments (P < 0.01) (Table 1). Lipid accumulation of embryos from PES was markedly lower than any other in vitro treatments (P < 0.01), but higher than in vivo embryos (3.31 ± 2.78 lipid granules) (P < 0.01). NaN3- and DNP-treated embryos both accumulated lipid similar to in vitro controls. No treatment differences were found in developmental competence when Day 7 embryos were transferred to recipients and recovered 1 week later (43 to 54% live embryos recovered), nor were there any significant differences (P > 0.1) in surface area. Embryos exposed to PES at the compaction and post-compaction stages accumulated much less lipid than controls or embryos exposed to other metabolic regulators, making this a very promising treatment. PES oxidizes NADPH; the molecular mechanism of PES appears to involve increased flux of glucose through the PPP while decreasing availability of NADPH for fatty acid synthesis. Table 1. Response of embryos to metabolic regulators

An outbreak of viral gastroenteritis following environmental contamination at a concert hall

In January 1999, an outbreak of viral gastroenteritis affected more than 300 people who attended a metropolitan concert hall over a 5-day period. Norwalk-like virus (NLV) was confirmed in faecal samples by reverse transcription polymerase chain reaction assay. The index case was a concert attendee who vomited in the auditorium and adjacent male toilet. Gastrointestinal illness occurred among members of 8/15 school parties who attended the following day. Children who sat on the same level of the auditorium as the index case were much more likely to be ill than those seated elsewhere (relative risk 7.1, 95% confidence interval 5.4-9.2. P < 0.001). The majority of other reported cases had not been present on the evening of the vomiting incident. Disinfection procedure was poor and the disinfectant used contained no sodium hypochlorite. Transmission most likely occurred through direct contact with contaminated fomites. The outbreak has implications for disinfection procedures following vomiting incidents at public venues.

Occupational injuries of physiotherapists in North and Central Queensland

The National Occupational Health and Safety Commission of Australia has identified musculoskeletal injuries in the health industry as a key area of concern. There is little data available on injuries to physiotherapists. This study aimed to investigate the nature, prevalence, job risk factors and consequences of occupational injuries, with particular focus on musculoskeletal injuries, experienced by physiotherapists in North and Central Queensland. A work-related musculoskeletal injury was defined as pain lasting more than three days that the respondent felt was cause by their work as a physiotherapist. Fifty-five per cent of respondents had experienced a work-related injury and 40% had experienced injury in the previous year. The most injured body areas were the low back, hands and neck. Over half (56%) of the initial episodes of injury occurred within five years of graduation. The job risk factors of most concern to injured respondents were sustained demanding postures, manual therapy techniques, repetition, working while injured and excessive workloads. Injured respondents chose to work while injured and not to take time off on workers' compensation or have surgery. Following injury, 38 of respondents changed work settings. Most injured physiotherapists modified their techniques to continue working. Further research is needed to develop effective preventative strategies.

Optimal dosing of penicillin G in the third trimester of pregnancy for prophylaxis against group B Streptococcus

OBJECTIVE

We wanted to determine the optimal dose of intravenous penicillin (PCN) in the third trimester of pregnancy for the prophylaxis of group B Streptococcus.

STUDY DESIGN

Healthy women in the third trimester with a singleton pregnancy were recruited. Eligibility included no previous penicillin or cephalosporin allergy and no history of renal disease. We obtained a baseline 24-hour urine collection for total protein concentration and creatinine clearance. Two intravenous catheters were placed, and 1 million units of penicillin G (PCN G) sodium was infused through one catheter. Serial blood samples were obtained through the second catheter at 1, 5, 15, 30, 60, 90, 120, 150, 180, 210, and 240 minutes. Serum was stored at -80 degrees C until assays were performed. Reverse-phase high-performance liquid chromatography was used to determine serum concentrations.

RESULTS

Fifteen patients met the requirements for eligibility. The average 24-hour urine sample for total protein concentration was 187 mg/dL (range, 11-252), and creatinine clearance was 191 mL/min (range, 137-245). Average maximum serum concentration (C(max)) was 67 microg/mL (range, 34-132) and was reached within 5 minutes. Average serum PCN concentration was 12 microg/mL (range, 9-25) after 4 hours of urine collection.

CONCLUSION

The C(max) was 67 microg/mL (670 x minimum inhibitory concentration). One million units of intravenous PCN G exceeds MIC in the treatment of GBS. The dosing interval should be 4 hours to ensure anti-GBS activity in all patients. More frequent dosing does not increase activity. Current recommendations for GBS prophylaxis which use PCN G should be modified pending future studies of neonatal PCN concentrations.

Dynamic publication model for neurophysiology databases

We have implemented a pair of database projects, one serving cortical electrophysiology and the other invertebrate neurones and recordings. The design for each combines aspects of two proven schemes for information interchange. The journal article metaphor determined the type, scope, organization and quantity of data to comprise each submission. Sequence databases encouraged intuitive tools for data viewing, capture, and direct submission by authors. Neurophysiology required transcending these models with new datatypes. Time-series, histogram and bivariate datatypes, including illustration-like wrappers, were selected by their utility to the community of investigators. As interpretation of neurophysiological recordings depends on context supplied by metadata attributes, searches are via visual interfaces to sets of controlled-vocabulary metadata trees. Neurones, for example, can be specified by metadata describing functional and anatomical characteristics. Permanence is advanced by data model and data formats largely independent of contemporary technology or implementation, including Java and the XML standard. All user tools, including dynamic data viewers that serve as a virtual oscilloscope, are Java-based, free, multiplatform, and distributed by our application servers to any contemporary networked computer. Copyright is retained by submitters; viewer displays are dynamic and do not violate copyright of related journal figures. Panels of neurophysiologists view and test schemas and tools, enhancing community support.

Drug use patterns among high school athletes and nonathletes

This study examined drug use patterns and perceptions of drug intervention programs among adolescent interscholastic athletes and nonathletes. In particular, it explored the issue of whether participation in high school athletics is related to a healthier lifestyle and decreased use of recreational drugs and ergogenic aids. One thousand five hundred fifteen Massachusetts high school students completed a 150-item survey that assessed illicit and nonillicit substance use. Chi-square analyses revealed that athletes were significantly less likely to use cocaine and psychedelics, and were less likely to smoke cigarettes, compared with nonathletes. Conversely, nonathletes were less likely to use creatine than were athletes. There was no difference in the use of anabolic steroids and androstenedione between athletes and nonathletes. Descriptive analyses appear to indicate that drug interventions for athletes are falling short of their objectives. This study suggests that athletes have a healthier lifestyle and that the efficacy of intervention programs must be further examined.