Choosing fluids to reduce the risks of acute electrolyte disturbances in children after a kidney transplant

Intravenous (i.v.) fluid therapy is critically important in pediatric kidney transplantation. Because of the high volumes given perioperatively, transplant recipients can develop significant electrolyte abnormalities depending on the types of fluids used. Current practices in pediatric transplantation aim to balance risks of hyponatremia from traditionally used hypotonic fluids, such as 0.45% sodium chloride, against hyperchloremia and acidosis associated with isotonic 0.9% sodium chloride. Using the balanced solution Plasma-Lyte 148 as an alternative might mitigate these risks.

Lipid Nanoparticles Deliver mRNA to the Brain after an Intracerebral Injection

Neurological disorders are often debilitating conditions with no cure. The majority of current therapies are palliative rather than disease-modifying; therefore, new strategies for treating neurological disorders are greatly needed. mRNA-based therapeutics have great potential for treating such neurological disorders; however, challenges with delivery have limited their clinical potential. Lipid nanoparticles (LNPs) are a promising delivery vector for the brain, given their safer toxicity profile and higher efficacy. Despite this, very little is known about LNP-mediated delivery of mRNA into the brain. Here, we employ MC3-based LNPs and successfully deliver Cre mRNA and Cas9 mRNA/Ai9 sgRNA to the adult Ai9 mouse brain; greater than half of the entire striatum and hippocampus was found to be penetrated along the rostro-caudal axis by direct intracerebral injections of MC3 LNP mRNAs. MC3 LNP Cre mRNA successfully transfected cells in the striatum (∼52% efficiency) and hippocampus (∼49% efficiency). In addition, we demonstrate that MC3 LNP Cas9 mRNA/Ai9 sgRNA edited cells in the striatum (∼7% efficiency) and hippocampus (∼3% efficiency). Further analysis demonstrates that MC3 LNPs mediate mRNA delivery to multiple cell types including neurons, astrocytes, and microglia in the brain. Overall, LNP-based mRNA delivery is effective in brain tissue and shows great promise for treating complex neurological disorders.

Balanced crystalloid solution versus saline in deceased donor kidney transplantation (BEST-Fluids): a pragmatic, double-blind, randomised, controlled trial

BACKGROUND

Delayed graft function (DGF) is a major adverse complication of deceased donor kidney transplantation. Intravenous fluids are routinely given to patients receiving a transplant to maintain intravascular volume and optimise graft function. Saline (0·9% sodium chloride) is widely used but might increase the risk of DGF due to its high chloride content. We aimed to test our hypothesis that using a balanced low-chloride crystalloid solution (Plasma-Lyte 148) instead of saline would reduce the incidence of DGF.

METHODS

BEST-Fluids was a pragmatic, registry-embedded, multicentre, double-blind, randomised, controlled trial at 16 hospitals in Australia and New Zealand. Adults and children of any age receiving a deceased donor kidney transplant were eligible; those receiving a multi-organ transplant or weighing less than 20 kg were excluded. Participants were randomly assigned (1:1) using an adaptive minimisation algorithm to intravenous balanced crystalloid solution (Plasma-Lyte 148) or saline during surgery and up until 48 h after transplantation. Trial fluids were supplied in identical bags and clinicians determined the fluid volume, rate, and time of discontinuation. The primary outcome was DGF, defined as receiving dialysis within 7 days after transplantation. All participants who consented and received a transplant were included in the intention-to-treat analysis of the primary outcome. Safety was analysed in all randomly assigned eligible participants who commenced surgery and received trial fluids, whether or not they received a transplant. This study is registered with Australian New Zealand Clinical Trials Registry, (ACTRN12617000358347), and ClinicalTrials.gov (NCT03829488).

FINDINGS

Between Jan 26, 2018, and Aug 10, 2020, 808 participants were randomly assigned to balanced crystalloid (n=404) or saline (n=404) and received a transplant (512 [63%] were male and 296 [37%] were female). One participant in the saline group withdrew before 7 days and was excluded, leaving 404 participants in the balanced crystalloid group and 403 in the saline group that were included in the primary analysis. DGF occurred in 121 (30%) of 404 participants in the balanced crystalloid group versus 160 (40%) of 403 in the saline group (adjusted relative risk 0·74 [95% CI 0·66 to 0·84; p<0·0001]; adjusted risk difference 10·1% [95% CI 3·5 to 16·6]). In the safety analysis, numbers of investigator-reported serious adverse events were similar in both groups, being reported in three (<1%) of 406 participants in the balanced crystalloid group versus five (1%) of 409 participants in the saline group (adjusted risk difference -0·5%, 95% CI -1·8 to 0·9; p=0·48).

INTERPRETATION

Among patients receiving a deceased donor kidney transplant, intravenous fluid therapy with balanced crystalloid solution reduced the incidence of DGF compared with saline. Balanced crystalloid solution should be the standard-of-care intravenous fluid used in deceased donor kidney transplantation.

FUNDING

Medical Research Future Fund and National Health and Medical Research Council (Australia), Health Research Council (New Zealand), Royal Australasian College of Physicians, and Baxter.

Cognition-Enhanced Machine Learning for Better Predictions with Limited Data

The fields of machine learning (ML) and cognitive science have developed complementary approaches to computationally modeling human behavior. ML's primary concern is maximizing prediction accuracy; cognitive science's primary concern is explaining the underlying mechanisms. Cross-talk between these disciplines is limited, likely because the tasks and goals usually differ. The domain of e-learning and knowledge acquisition constitutes a fruitful intersection for the two fields' methodologies to be integrated because accurately tracking learning and forgetting over time and predicting future performance based on learning histories are central to developing effective, personalized learning tools. Here, we show how a state-of-the-art ML model can be enhanced by incorporating insights from a cognitive model of human memory. This was done by exploiting the predictive performance equation's (PPE) narrow but highly specialized domain knowledge with regard to the temporal dynamics of learning and forgetting. Specifically, the PPE was used to engineer timing-related input features for a gradient-boosted decision trees (GBDT) model. The resulting PPE-enhanced GBDT outperformed the default GBDT, especially under conditions in which limited data were available for training. Results suggest that integrating cognitive and ML models could be particularly productive if the available data are too high-dimensional to be explained by a cognitive model but not sufficiently large to effectively train a modern ML algorithm. Here, the cognitive model's insights pertaining to only one aspect of the data were enough to jump-start the ML model's ability to make predictions-a finding that holds promise for future explorations.

Gene Therapy: The Next-Generation Therapeutics and Their Delivery Approaches for Neurological Disorders

Neurological conditions like neurodevelopmental disorders and neurodegenerative diseases are quite complex and often exceedingly difficult for patients. Most of these conditions are due to a mutation in a critical gene. There is no cure for the majority of these neurological conditions and the availability of disease-modifying therapeutics is quite rare. The lion's share of the treatments that are available only provide symptomatic relief, as such, we are in desperate need of an effective therapeutic strategy for these conditions. Considering the current drug development landscape, gene therapy is giving us hope as one such effective therapeutic strategy. Consistent efforts have been made to develop gene therapy strategies using viral and non-viral vectors of gene delivery. Here, we have discussed both of these delivery methods and their properties. We have summarized the relative advantages and drawbacks of viral and non-viral vectors from the perspectives of safety, efficiency, and productivity. Recent developments such as clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated gene editing and its use in vivo have been described here as well. Given recent advancements, gene therapy shows great promise to emerge as a next-generation therapeutic for many of the neurodevelopmental and neurodegenerative conditions.

Evaluation of the TMRW vapor phase cryostorage platform using reproductive specimens and in vitro extended human embryo culture

OBJECTIVE

To assess the impact of shipment and storage of sperm, oocytes, and blastocysts in vapor phase nitrogen compared with static storage in liquid phase nitrogen.

DESIGN

Prospective cohort-matched study.

SETTING

Multiple in vitro fertilization laboratories in an in vitro fertilization network.

PATIENT(S)

Fifty-eight human embryos, 32 human oocytes, 15 units of bovine semen.

INTERVENTION(S)

Vapor vs. liquid nitrogen.

MAIN OUTCOME MEASURE(S)

The postwarming survival of oocytes, sperm, and blastocysts, and the developmental potential of blastocysts during in vitro extended culture.

RESULT(S)

Custom-designed labware, for use with the TMRW platform, enables continuous temperature monitoring during shipment and/or storage in the vapor phase robotic storage system. The highest temperature recorded for specimens shipped to a domestic laboratory was -180.2 °C with a mean ± SD of -190.4 ± 0.5 °C during shipment and -181.1 ± 0.6 °C during storage. Likewise, specimens shipped internationally had a high of -180.2 °C with a mean ± SD of -193.5 ± 0.6 °C during shipment and -181.2 ± 0.7 °C during storage. Results from the extended culture assays have revealed no deleterious effect of shipment and storage in nitrogen vapor. The viability of mammalian gametes and embryos was equivalent between the vapor phase and liquid phase storage.

CONCLUSION(S)

The evaluated system did not have any deleterious effects on the postwarming survival of sperm, oocytes, and blastocysts. The postwarming developmental potential of human blastocysts during in vitro extended culture was unaffected by storage and handling in the vapor phase nitrogen TMRW platform when compared with static liquid phase nitrogen storage. Our results suggest that the vapor phase cryostorage platform is a safe system to handle and store reproductive specimens for human assisted reproductive technology.

Interactions Between Donor Age and 12-Month Estimated Glomerular Filtration Rate on Allograft and Patient Outcomes After Kidney Transplantation

Reduced estimated glomerular filtration rate (eGFR) at 12-months after kidney transplantation is associated with increased risk of allograft loss, but it is uncertain whether donor age and types modify this relationship. Using Australia and New Zealand registry data, multivariable Cox proportional modelling was used to examine the interactive effects between donor age, types and 12-month eGFR on overall allograft loss. We included 11,095 recipients (4,423 received live-donors). Recipients with lowest 12-month eGFR (<30 ml/min/1.73 m²) experienced the greatest risk of allograft loss, with adjusted HR [95% CI) of 2.65 [2.38–2.95] compared to eGFR of 30–60 ml/min/1.73 m²; whereas the adjusted HR for highest eGFR (>60 ml/min/1.73 m²) was 0.67 [0.62–0.74]. The association of 12-month eGFR and allograft loss was modified by donor age (but not donor types) where a higher risk of allograft loss in recipients with lower compared with higher 12-month eGFR being most pronounced in the younger donor age groups (p < 0.01). Recipients with eGFR <30 ml/min/1.73 m² 12-months after transplantation experienced ≥2.5-fold increased risk of overall allograft loss compared to those with eGFR of >60 ml/min/1.73 m², and the magnitude of the increased risk is most marked among recipients with younger donors. Careful deliberation of other factors including donor age when considering eGFR as a surrogate for clinical endpoints is warranted.

Statistical analysis plan for Better Evidence for Selecting Transplant Fluids (BEST-Fluids): a randomised controlled trial of the effect of intravenous fluid therapy with balanced crystalloid versus saline on the incidence of delayed graft function in deceased donor kidney transplantation

Background

Delayed graft function, or the requirement for dialysis due to poor kidney function, is a frequent complication of deceased donor kidney transplantation that is associated with inferior outcomes. Intravenous fluids with a high chloride content, such as isotonic sodium chloride (0.9% saline), are widely used in transplantation but may increase the risk of poor kidney function. The primary objective of the BEST-Fluids trial is to compare the effect of a balanced low-chloride crystalloid, Plasma-Lyte 148 (Plasmalyte), versus 0.9% saline on the incidence of DGF in deceased donor kidney transplant recipients. This article describes the statistical analysis plan for the trial.

Methods and design

BEST-Fluids is an investigator-initiated, pragmatic, registry-based, multi-centre, double-blind, randomised controlled trial. Eight hundred patients (adults and children) in Australia and New Zealand with end-stage kidney disease admitted for a deceased donor kidney transplant were randomised to intravenous fluid therapy with Plasmalyte or 0.9% saline in a 1:1 ratio using minimization. The primary outcome is delayed graft function (dialysis within seven days post-transplant), which will be modelled using a log-binomial generalised linear mixed model with fixed effects for treatment group, minimization variables, and ischaemic time and a random intercept for study centre. Secondary outcomes including early kidney transplant function (a ranked composite of dialysis duration and the rate of graft function recovery), treatment for hyperkalaemia, and graft survival and will be analysed using a similar modelling approach appropriate for the type of outcome.

Discussion

BEST-Fluids will determine whether Plasmalyte reduces the incidence of DGF and has a beneficial effect on early kidney transplant outcomes relative to 0.9% saline and will inform clinical guidelines on intravenous fluids for deceased donor kidney transplantation. The statistical analysis plan describes the analyses to be undertaken and specified before completion of follow-up and locking the trial databases.

Trial registration

Australian New Zealand Clinical Trials Registry ACTRN12617000358347. Prospectively registered on 8 March 2017

ClinicalTrials.gov identifier NCT03829488. Registered on 4 February 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05989-w.

Trust Miscalibration Is Sometimes Necessary: An Empirical Study and a Computational Model

The literature on trust seems to have reached a consensus that appropriately calibrated trust in humans or machines is highly desirable; miscalibrated (i.e., over- or under-) trust has been thought to only have negative consequences (i.e., over-reliance or under-utilization). While not invalidating the general idea of trust calibration, a published computational cognitive model of trust in strategic interaction predicts that some local and temporary violations of the trust calibration principle are critical for sustained success in strategic situations characterized by interdependence and uncertainty (e.g., trust game, prisoner’s dilemma, and Hawk-dove). This paper presents empirical and computational modeling work aimed at testing the predictions of under- and over-trust in an extension of the trust game, the multi-arm trust game, that captures some important characteristics of real-world interpersonal and human-machine interactions, such as the ability to choose when and with whom to interact among multiple agents. As predicted by our previous model, we found that, under conditions of increased trust necessity, participants actively reconstructed their trust-investment portfolios by discounting their trust in their previously trusted counterparts and attempting to develop trust with the counterparts that they previously distrusted. We argue that studying these exceptions of the principle of trust calibration might be critical for understanding long-term trust calibration in dynamic environments.

Patient and center characteristics associated with kidney transplant outcomes: a binational registry analysis

This registry-based study evaluated the contribution of center characteristics to kidney transplant outcomes in adult first kidney transplant recipients in Australia and New Zealand between 2004 and 2014. Primary outcomes were mortality and graft failure, and secondary outcomes were transplant complications. Overall, 6970 transplants from 17 centers were included. For deceased donor transplants, 5-year patient and graft survival rates varied considerably (81.0-93.9% and 72.2-88.3%, respectively). Variations in mortality and graft failure were partially reduced after adjustment for patient characteristics (1% and 20% reductions) and more markedly reduced after adjustment for center characteristics (41% and 55% reductions). For living donor transplants, 5-year patient and graft survival rates varied (89.7-100% and 79.2-96.9%, respectively). Centers with high average total ischemic times (>14 h) were associated with higher mortality for both deceased (adjusted hazard ratio [(AHR] 2.24, 95% CI 1.21-4.13) and living donor transplants (AHR 1.76, 95% CI 1.02-3.04). Small center size (<35 new kidney transplants/year) was associated with a lower hazard of mortality for living donor kidney transplants (AHR 0.48, 95% CI 0.28-0.81). No center characteristic was associated with graft failure. The appreciable variations in deceased donor kidney transplant recipient and graft survival outcomes across centers were attributable to center effects.

Study Protocol for Better Evidence for Selecting Transplant Fluids (BEST-Fluids): a pragmatic, registry-based, multi-center, double-blind, randomized controlled trial evaluating the effect of intravenous fluid therapy with Plasma-Lyte 148 versus 0.9% saline on delayed graft function in deceased donor kidney transplantation

Background

Delayed graft function, the requirement for dialysis due to poor kidney function post-transplant, is a frequent complication of deceased donor kidney transplantation and is associated with inferior outcomes and higher costs. Intravenous fluids given during and after transplantation may affect the risk of poor kidney function after transplant. The most commonly used fluid, isotonic sodium chloride (0.9% saline), contains a high chloride concentration, which may be associated with acute kidney injury, and could increase the risk of delayed graft function. Whether using a balanced, low-chloride fluid instead of 0.9% saline is safe and improves kidney function after deceased donor kidney transplantation is unknown.

Methods

BEST-Fluids is an investigator-initiated, pragmatic, registry-based, multi-center, double-blind, randomized controlled trial. The primary objective is to compare the effect of intravenous Plasma-Lyte 148 (Plasmalyte), a balanced, low-chloride solution, with the effect of 0.9% saline on the incidence of delayed graft function in deceased donor kidney transplant recipients. From January 2018 onwards, 800 participants admitted for deceased donor kidney transplantation will be recruited over 3 years in Australia and New Zealand. Participants are randomized 1:1 to either intravenous Plasmalyte or 0.9% saline peri-operatively and until 48 h post-transplant, or until fluid is no longer required; whichever comes first. Follow up is for 1 year. The primary outcome is the incidence of delayed graft function, defined as dialysis in the first 7 days post-transplant. Secondary outcomes include early kidney transplant function (composite of dialysis duration and rate of improvement in graft function when dialysis is not required), hyperkalemia, mortality, graft survival, graft function, quality of life, healthcare resource use, and cost-effectiveness. Participants are enrolled, randomized, and followed up using the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry.

Discussion

If using Plasmalyte instead of 0.9% saline is effective at reducing delayed graft function and improves other clinical outcomes in deceased donor kidney transplantation, this simple, inexpensive change to using a balanced low-chloride intravenous fluid at the time of transplantation could be easily implemented in the vast majority of transplant settings worldwide.

Trial registration

Australian New Zealand Clinical Trials Registry: ACTRN12617000358347. Registered on 8 March 2017. ClinicalTrials.gov: NCT03829488. Registered on 4 February 2019.

Effects of Renal Impairment on the Pharmacokinetics, Efficacy, and Safety of Inclisiran: An Analysis of the ORION-7 and ORION-1 Studies

OBJECTIVE

To investigate the pharmacodynamic properties of inclisiran, a small interfering RNA targeting proprotein convertase subtilisin-kexin type 9 (PCSK9), in individuals with normal renal function and renal impairment (RI).

PATIENTS AND METHODS

The analysis included participants with normal renal function and mild, moderate, and severe RI from the phase 1 ORION-7 renal study (n=31) and the phase 2 ORION-1 study (n=247) who received 300 mg of inclisiran sodium or placebo.

RESULTS

In ORION-7, PCSK9 values were reduced at day 60 in the normal renal function group (68.1%±12.4%), mild RI group (74.2%±12.3%), moderate RI group (79.8%±4.9%), and severe RI group (67.9%±16.4%) (P<.001 vs placebo in all groups). Low-density lipoprotein cholesterol levels were significantly reduced versus placebo: normal renal function, 57.6%±10.7%; mild RI, 35.1%±13.5%; moderate RI, 53.1%±21.3%; severe RI, 49.2%±26.6% (P<.001 for all). In ORION-1, PCSK9 level reductions at day 180 were 48.3% to 58.6% in the 300-mg single-dose groups and 67.3% to 73.0% in the 300-mg 2-dose groups (P<.001 vs placebo in all groups). The corresponding low-density lipoprotein cholesterol level reductions were 35.7% to 40.2% in the 300-mg single-dose groups and 50.9% to 58.0% in the 300 mg 2-dose groups (P<.001 vs placebo in all groups). In ORION-7, exposure to inclisiran was proportionally greater in individuals with increasing RI; inclisiran was undetectable in plasma 48 hours after administration in any group.

CONCLUSION

The pharmacodynamic effects and safety profile of inclisiran were similar in study participants with normal and impaired renal function. Dose adjustments of inclisiran are not required in these patients.

TRIAL REGISTRATION

clinicaltrials.gov Identifiers: NCT02597127 and NCT03159416.

Toward a Unified Theory of Learned Trust in Interpersonal and Human-Machine Interactions

A proposal for a unified theory of learned trust implemented in a cognitive architecture is presented. The theory is instantiated as a computational cognitive model of learned trust that integrates several seemingly unrelated categories of findings from the literature on interpersonal and human-machine interactions and makes unintuitive predictions for future studies. The model relies on a combination of learning mechanisms to explain a variety of phenomena such as trust asymmetry, the higher impact of early trust breaches, the black-hat/white-hat effect, the correlation between trust and cognitive ability, and the higher resilience of interpersonal as compared to human-machine trust. In addition, the model predicts that trust decays in the absence of evidence of trustworthiness or untrustworthiness. The implications of the model for the advancement of the theory on trust are discussed. Specifically, this work suggests two more trust antecedents on the trustor's side: perceived trust necessity and cognitive ability to detect cues of trustworthiness.

A Randomized Controlled Trial of an Intensive Nutrition Intervention Versus Standard Nutrition Care to Avoid Excess Weight Gain After Kidney Transplantation: The INTENT Trial

OBJECTIVE

Excessive weight gain is common after kidney transplantation and increases cardiovascular risk. The aim of this randomized controlled trial was to determine whether an intensive nutrition and exercise intervention delivered alongside routine post-transplant care would reduce post-transplant weight gain.

DESIGN

Single-blind, randomized controlled trial.

SUBJECTS AND SETTING

Adult kidney transplant recipients at a regional transplant center were recruited during routine outpatient clinic visits in the first month after transplant. Patients with a body mass index >40 kg/m² or <18.5 kg/m², severe malnutrition, or ongoing medical complications were excluded.

INTERVENTION

Participants were randomized to intensive nutrition intervention (individualized nutrition and exercise counselling; 12 dietitian visits; 3 exercise physiologist visits over 12 months) or to standard nutrition care (guideline based; 4 dietitian visits).

MAIN OUTCOME MEASURES

The primary outcome was weight at 6 months after transplant adjusted for baseline weight, obesity, and gender, analyzed using analysis of covariance. The secondary outcomes included body composition, biochemistry, quality of life, and physical function.

RESULTS

Thirty-seven participants were randomized to the intensive intervention (n = 19) or to standard care (n = 18); one intensive group participant withdrew before baseline. Weight increased between baseline, 6 and 12 months (78.0 ± 13.7 [standard deviation], 79.6 ± 13.0 kg, 81.6 ± 12.9 kg; mean change 4.6% P < .001) but at 6 months did not differ significantly between the groups: 77.0 ± 12.4 kg (intensive); 82.2 ± 13.4 kg (standard); difference in adjusted means 0.4 kg (95% confidence interval: -2.2 to 3.0 kg); analysis of covariance P = .7. No between-group differences in secondary outcomes were observed. Across the whole cohort, total body protein and physical function (gait speed, sit to stand, grip strength, physical activity, and quality of life [all but 2 domains]) improved. However, adverse changes were seen for total body fat, HbA1c, and fasting glucose across the cohort.

CONCLUSIONS

Kidney transplant recipients in the first year after transplant did not benefit from an intensive nutrition intervention compared with standard nutrition care, although weight gain was relatively modest in both groups.

Comparison of graft and patient outcomes following kidney transplantation in extended hour and conventional haemodialysis patients

AIM

Differences in early graft function between kidney transplant recipients previously managed with either haemodialysis (HD) or peritoneal dialysis are well described. However, only two single-centre studies have compared graft and patient outcomes between extended hour and conventional HD patients, with conflicting results.

METHODS

This study compared the outcomes of all extended hour (≥24 h/week) and conventional HD patients transplanted in Australia and New Zealand between 2000 and 2014. The primary outcome was delayed graft function (DGF), defined in an ordinal manner as either a spontaneous fall in serum creatinine of less than 10% within 24 h, or the need for dialysis within 72 h following transplantation. Secondary outcomes included the requirement for dialysis within 72 h post-transplant, acute rejection, estimated glomerular filtration rate at 12 months, death-censored graft failure, all-cause and cardiovascular mortality, and a composite of graft failure and mortality.

RESULTS

A total of 4935 HD patients (378 extended hour HD, 4557 conventional HD) received a kidney transplant during the study period. Extended hour HD was associated with an increased likelihood of DGF compared with conventional HD (adjusted proportional odds ratio 1.33; 95% confidence interval 1.06-1.67). There was no significant difference between extended hour and conventional HD in terms of any of the secondary outcomes.

CONCLUSION

Compared to conventional HD, extended hour HD was associated with DGF, although long-term graft and patient outcomes were not different.

Effects of Type of Comparative Advertisement on Responses to the Advertisement and the Advertised Product

The effects of four types of comparative advertisements, based on Shimp's 1975 typology, on multiple advertisement-related and product-related responses for two product classes and two levels of brand visibility were examined. Groups of 20 college students each read one type of comparative advertisement for one combination of product class and brand visibility as part of a booklet containing general interest articles and other noncomparative advertisements. Analyses of responses to the advertisements and the advertised products indicated that the type of advertisement significantly affected advertisement-related responses but had a significant effect on only one of the product-related responses. Specification of the attribute of comparison was more salient than the specification of the comparison brand.

Cognitive Model of Trust Dynamics Predicts Human Behavior within and between Two Games of Strategic Interaction with Computerized Confederate Agents

When playing games of strategic interaction, such as iterated Prisoner's Dilemma and iterated Chicken Game, people exhibit specific within-game learning (e.g., learning a game's optimal outcome) as well as transfer of learning between games (e.g., a game's optimal outcome occurring at a higher proportion when played after another game). The reciprocal trust players develop during the first game is thought to mediate transfer of learning effects. Recently, a computational cognitive model using a novel trust mechanism has been shown to account for human behavior in both games, including the transfer between games. We present the results of a study in which we evaluate the model's a priori predictions of human learning and transfer in 16 different conditions. The model's predictive validity is compared against five model variants that lacked a trust mechanism. The results suggest that a trust mechanism is necessary to explain human behavior across multiple conditions, even when a human plays against a non-human agent. The addition of a trust mechanism to the other learning mechanisms within the cognitive architecture, such as sequence learning, instance-based learning, and utility learning, leads to better prediction of the empirical data. It is argued that computational cognitive modeling is a useful tool for studying trust development, calibration, and repair.

Patients' administration preferences: progesterone vaginal insert (Endometrin®) compared to intramuscular progesterone for Luteal phase support

Background

Administration of exogenous progesterone for luteal phase support has become a standard of practice. Intramuscular (IM) injections of progesterone in oil (PIO) and vaginal administration of progesterone are the primary routes of administration. This report describes the administration preferences expressed by women with infertility that were given progesterone vaginal insert (PVI) or progesterone in oil injections (PIO) for luteal phase support during fresh IVF cycles.

Methods

A questionnaire to assess the tolerability, convenience, and ease of administration of PVI and PIO given for luteal phase support was completed by infertile women diagnosed with PCOS and planning to undergo IVF. The women participated in an open-label study of highly purified human menopausal gonadotropins (HP-hMG) compared with recombinant FSH (rFSH) given for stimulation of ovulation.

Results

Most women commented on the convenience and ease of administration of PVI, while a majority of women who administered IM PIO described experiencing pain. In addition, their partners often indicated that they had experienced at least some anxiety regarding the administration of PIO. The most distinguishing difference between PVI and PIO in this study was the overall patient preference for PVI. Despite the need to administer PVI either twice a day or three times a day, 82.6% of the patients in the PVI group found it “very” or “somewhat convenient” compared with 44.9% of women in the PIO group.

Conclusions

The results of this comprehensive, prospective patient survey, along with findings from other similar reports, suggest that PVI provides an easy-to-use and convenient method for providing the necessary luteal phase support for IVF cycles without the pain and inconvenience of daily IM PIO. Moreover, ongoing pregnancy rates with the well-tolerated PVI were as good as the pregnancy rates with PIO.

Trial registration

ClinicalTrial.gov, NCT00805935

Electronic supplementary material

The online version of this article (doi:10.1186/1742-4755-11-78) contains supplementary material, which is available to authorized users.

Progesterone pharmacokinetics and pharmacodynamics with 3 dosages and 2 regimens of an effervescent micronized progesterone vaginal insert

CONTEXT

Progesterone vaginal insert (PVI), an effervescent delivery system, dissolves rapidly, is absorbed through the vaginal epithelium, and achieves higher endometrial tissue concentrations than those achieved with progesterone in oil (PIO) given im.

OBJECTIVE

Our objective was to examine the pharmacokinetics and pharmacodynamics of PVI compared with PIO.

DESIGN, SETTING, AND PARTICIPANTS

Fifty-eight healthy premenopausal women were randomized to 50, 100, or 200 mg PVI once daily; 100 or 200 mg PVI twice daily; or 50 to 100 mg PIO via im injection once daily for 10 days. Serum samples were obtained after the first dose; serum and endometrial tissue were obtained after the last dose.

MAIN OUTCOME MEASURES

Maximum observed serum concentration (Cmax), time to Cmax, and area under the serum-concentration time curve over the dosing interval were calculated after correcting for baseline progesterone concentrations. ANOVA and paired t test were used to compare results across and within groups.

RESULTS

A higher Cmax was observed after PIO than PVI administration. Endometrial tissue progesterone concentrations were higher for PVI regimens. Time to Cmax was 7.3 hours after PIO and 3.3 to 5.9 hours after PVI. Steady state was achieved within 24 and 48 hours for PVI and PIO regimens, respectively. The area under the curve increased with increasing PVI dosage; however, the increase was not proportional to the increase in dosage. Downregulation of estrogen and progesterone receptors was observed in secretory biopsy specimens.

CONCLUSION

The PVI system consistently allowed for rapid progesterone absorption and achieved higher endometrial tissue concentrations and lower systemic exposures than observed after im PIO.

The effect of intensive nutrition interventions on weight gain after kidney transplantation: protocol of a randomised controlled trial

BACKGROUND

Weight gain and obesity are common after kidney transplantation, particularly during the first year. Obesity is a risk factor for the development of new-onset diabetes after transplantation, and is associated with reduced graft survival. There is a lack of evidence for effective interventions to prevent weight gain after kidney transplantation.

METHODS/DESIGN

The effect of INTEnsive Nutrition interventions on weight gain after kidney Transplantation (INTENT) trial is a single-blind (outcomes assessor), randomised controlled trial to assess the effect of intensive nutrition interventions, including exercise advice, on weight gain and metabolic parameters in the first year after transplantation. Participants will be randomised during the first post-transplant month to either standard care (four visits with a renal dietitian over twelve months) or intensive nutrition intervention (eight visits with a renal dietitian over the first six months, four visits over the second six months, and three visits over the first six months with an exercise physiologist). In the intensive intervention group, nutrition counselling will be provided using motivational interviewing techniques to encourage quality engagement. Collaborative goal setting will be used to develop personalised nutrition care plans. Individualised advice regarding physical activity will be provided by an exercise physiologist. The primary outcome of the study is weight at six months after transplant, adjusted for baseline (one month post-transplant) weight, obesity and gender. Secondary outcomes will include changes in weight and other anthropometric measures over 12 months, body composition (in vivo neutron activation analysis, total body potassium, dual-energy X-ray absorptiometry, and bioelectrical impedance), biochemistry (fasting glucose, lipids, haemoglobin A1c and insulin), dietary intake and nutritional status, quality of life, and physical function.

DISCUSSION

There are currently few randomised clinical trials of nutrition interventions after kidney transplantation. The INTENT trial will thus provide important data on the effect of intensive nutrition interventions on weight gain after transplant and the associated metabolic consequences. Additionally, by assessing changes in glucose metabolism, the study will also provide data on the feasibility of undertaking larger multi-centre trials of nutrition interventions to reduce the incidence or severity of diabetes after transplantation.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry Number: ACTRN12614000155695.

Clinical comparison of ovarian stimulation and luteal support agents in patients undergoing GnRH antagonist IVF cycles

OBJECTIVE

To explore the comparative efficacy, safety, and tolerability of agents used for ovarian stimulation and luteal support when applied in a population of women undergoing in vitro fertilization (IVF) using a gonadotropin-releasing hormone (GnRH) antagonist protocol.

STUDY DESIGN

A phase 4, multicenter, randomized, open-label, exploratory clinical trial was performed at 7 assisted reproductive technology centers in the United States. Subjects included 173 women aged 18-42 years with a documented history of infertility who were undergoing IVF. Subjects were randomized to treatment with highly purified human menopausal gonadotropin (HP-hMG) or recombinant human follicle-stimulating hormone (rhFSH) for ovarian stimulation and progesterone vaginal inserts (PVIs) or intramuscular injection of progesterone in oil (PIO) for luteal support. Protocols for IVF followed the standard practices of participating centers within the parameters of the study.

RESULTS

Biochemical, clinical, and ongoing pregnancy rates were the main outcome measures. Ongoing pregnancy rates for individual treatment groups ranged from 44.0-46.9%. No statistically significant differences were observed in pregnancy outcomes for the comparisons of HP-hMG vs. rhFSH or PVI vs. PIO. All study medications were generally safe and well tolerated.

CONCLUSION

In this study HP-hMG and rhFSH were equally effective for ovarian stimulation during GnRH antagonist IVF cycles. Both PVI and PIO are viable options for luteal support.

Screening for colorectal cancer and advanced colorectal neoplasia in kidney transplant recipients: cross sectional prevalence and diagnostic accuracy study of faecal immunochemical testing for haemoglobin and colonoscopy

OBJECTIVE

To investigate whether screening kidney transplant recipients aged over 50 years for colorectal cancer with a faecal immunochemical test for haemoglobin might be justified, by determining the prevalence of advanced colorectal neoplasia and evaluating the diagnostic accuracy of faecal haemoglobin testing compared with colonoscopy in a population of kidney transplant recipients at otherwise average risk.

DESIGN

Cross sectional prevalence and diagnostic accuracy study with index test of faecal haemoglobin and reference standard of colonoscopy.

SETTING

Outpatient clinics in metropolitan and regional hospitals in South Australia.

PARTICIPANTS

229 kidney transplant recipients aged 50 years and over, who were at least 6 months (mean 9.0 (SD 8.4) years) post-transplant and otherwise at average risk of colorectal cancer, completed the study between June 2008 and October 2011.

INTERVENTIONS

Faecal immunochemical testing (Enterix Insure) for human haemoglobin, followed by colonoscopy with histological evaluation of retrieved samples.

MAIN OUTCOME MEASURES

Prevalence of advanced colorectal neoplasia, defined as an adenoma at least 10 mm in diameter, villous features, high grade dysplasia, or colorectal cancer; sensitivity, specificity, and predictive values of faecal haemoglobin testing for advanced neoplasia compared with colonoscopy.

RESULTS

Advanced colorectal neoplasia was found in 29 (13%, 95% confidence interval 9% to 18%) participants, including 2% (n=4) with high grade dysplasia and 2% (n=5) with colorectal cancer. Faecal testing for haemoglobin was positive in 12% (n=28); sensitivity, specificity, and positive and negative predictive values for advanced neoplasia were 31.0% (15.3% to 50.8%), 90.5% (85.6% to 94.2%), 32.1% (15.9% to 52.4%), and 90.1% (85.1% to 93.8%). Colonoscopy was well tolerated, with no significant adverse outcomes. To identify one case of advanced neoplasia, 8 (6 to 12) colonoscopies were needed.

CONCLUSIONS

Kidney transplant recipients aged over 50 years have a high prevalence of advanced colorectal neoplasia. Faecal haemoglobin screening for colorectal neoplasia has similar performance characteristics in transplant recipients to those reported in general population studies, with poor sensitivity but reasonable specificity. Surveillance colonoscopy might be a more appropriate approach in this population.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12608000154303.

Decreased gonadotropin requirements in once daily compared to twice daily administration: a prospective, randomized study

OBJECTIVE

Despite the lack of any scientific data, many ART programs split the daily gonadotropin dose during ovarian stimulation, while others give the entire dose during a single administration, usually at night.

DESIGN

Prospective randomized.

PATIENT(S)

213 women undergoing IVF/ICSI cycles at a single private ART center.

INTERVENTION(S)

Gonadotropin administration once daily compared to twice daily.

MAIN OUTCOME MEASURE(S)

Gonadotropin usage, clinical and ongoing PR RESULTS: There were 110 women in the once daily compared to 103 in the twice daily arm. All cycles were blastocyst transfers. There was a significantly lower FSH use in the once daily arm compared to the twice daily arm (1507.5 ± 517.5 IU vs. 1702.5 ± 622.5, P = 0.015), and a trend towards lower hMG use in the once daily arm (1342.5 ± 562.5 IU vs. 1462.5 ± 645.0, P = 0.15), without compromising clinical pregnancy rate (PR) (71.8% vs. 70.9%, P = NS) or delivery/ongoing PR (58.2% vs. 62.1%, P = NS). There were no differences in age, body mass index (BMI), peak estradiol, peak progesterone, retrieved oocytes, fertilized oocytes, number of ET, or PR.

CONCLUSIONS

Once daily administration is associated with lower gonadotropin usage without compromising success rates.

Non-human primate dendritic cells

Non-human primates (NHP) are essential translational models for biomedical research. Dendritic cells (DC) are a group of antigen presenting cells (APC) that play pivotal roles in the immunobiology of health and disease and are attractive cells for adoptive immunotherapy to stimulate and suppress immunity. DC have been studied extensively in humans and mice but until recently, have not been well characterized in NHP. This review considers the available data about DC across a range of NHP species and summarizes the understanding of in vitro-propagated DC and in vivo-isolated DC, which is now established. It is clear that although NHP DC exist within the paradigm of human DC, there are important functional and phenotypic differences when compared with human DC subsets. These differences need to be taken into account when designing preclinical, translational studies of DC therapy using NHP models.

Land-use suitability analysis in the United States: historical development and promising technological achievements

Various methods of spatial analysis are commonly used in land-use plans and site selection studies. A historical overview and discussion of contemporary developments of land-use suitability analysis are presented. The paper begins with an exploration into the early 20th century with the infancy of documented applications of the technique. The article then travels through the 20th century, documenting significant milestones. Concluding with present explorations of advanced technologies such as neural computing and evolutionary programming, this work is meant to serve as a foundation for literature review and a premise for the exploration of new advancements as we enter into the 21st century.

Validity of lower extremity strength and power utilizing a new closed chain dynamometer

PURPOSE

The purpose of this study was to compare selected variables measured on a traditional isokinetic dynamometer (Cybex II) with a new lower extremity, closed chain dynamometer (Omnikinetic, OmK).

METHODS

Twelve subjects (6 male, 6 female, age = 28+/-5 yr, mean +/- SD) performed Cybex II knee flexion and extension at 1.05, 3.14, and 5.23 rad x s(-1). A maximal effort of 10 repetitions of lower extremity concentric extension and eccentric flexion at 36% of subject's 1-RM was performed on the OmK. Crank power and joint (ankle, knee, and hip) kinetics were recorded as a mean of 10 repetitions.

RESULTS

t-Tests revealed right versus left leg differences (P < 0.05) for Cybex II peak torque flexion at 5.23 rad x s(-1), and OmK knee and hip peak power and hip root mean square power (RMS) power. Cybex peak knee torques were related (Pearson r values 0.78-0.92, P < 0.01) to OmK peak knee torques. Cybex average power was related to OmK knee power (Pearson r values 0.71-0.96, P < 0.01) and OmK crank power (r = 0.62-0.94, P < .01). Correlations tended to be stronger comparing the OmK with the fastest (5.23 rad x s(-1)) Cybex II speed.

CONCLUSIONS

These results suggest that the OmK knee and crank kinetic data are comparable to Cybex It isokinetic dynamometry. The ability to evaluate lower extremity joint exercise at a subject's maximal movement speed, in addition to the use of a closed-chain, multi-joint motion, may allow for the OmK to provide a more global evaluation of lower extremity kinetics during seated concentric-extension, eccentric-flexion exercise.

Medical students and debt: a survey of students at the School of Medicine, University of Auckland

AIMS

To assess the extent of Auckland medical students' debt, the types of debt accrued and to establish data on part-time employment, income, parental support and living circumstances for these students.

METHODS

Medical students at the University of Auckland were asked to complete a written survey questionnaire, which was distributed in lecture classes for years 1-5 and by mail for year 6. The questionnaire asked about biographical data, types and amounts of debt, the use of student loan scheme money, employment, income, student allowances, parental financial support and living situation. Students not sent the survey by mail were informed about the survey several days prior to receiving it to enable them to collate the necessary financial information. Data entry was completed via an electronic scanning system and questionnaire responses were analysed using a tabular analysis of the various classes.

RESULTS

There were 522 responses received, comprising 73% of students (48% male, 52% female). The major source of debt was to the Government student loan scheme (39% of students in year 1, rising to 75% in year 6). Average (median) debt to the Government loan scheme rises from $5000 in year 1 to $26,000 in year 6. Fourteen per cent of students receive a targeted student allowance and 30% have a part-time job. Average summer vacation earnings do not exceed $4000. Thirty-four percent receive no financial support from their parents and 18% receive support with some costs only. With the exceptions of students in year 1, more than 50% of students live away from home.

CONCLUSION

Medical students are predominantly in debt to the Government student loan scheme and the level rises by approximately $5000 per year from year 1 to year 6. It is expected that these levels will increase in the future.

Factors producing elevated core temperature in spontaneously hypertensive rats

Core temperature (Tco) of the spontaneously hypertensive rat (SHR) is consistently higher by approximately 1 degree C than that of normotensive controls. To analyze factors producing the elevated Tco, mean skin temperature (Tsk), metabolic heat production (M), respiratory evaporative heat loss (Eres), effective tissue thermal conductance (K), systolic blood pressure (BP), and Tco were determined in eight male SHR and nine male normotensive Wistar-Kyoto (WKY) rats habituated to rest quietly in neck stock restraint while exposed to ambient temperatures (Ta) of 12.5, 17, 23, 28.5, 32, 34, and 35 degrees C. At all temperatures steady-state BP, Tco, and M were higher for SHR's than for WKY's. SHR's could maintain thermal balance up to Ta 32 degrees C, and WKY's up to 34 degrees C. Eres from SHR's was greater than from WKY's at Ta of 12.5, 17, and 28.5 degrees C. K of SHR's was not different from or was higher than K of WKY's, and K for both groups was 2.6 times greater at Ta 32 degrees C than at 17 degrees C. These results indicate that the high Tco of SHR's is due to increased M uncompensated by increased K or Eres.