Engineering immune-evasive allogeneic cellular immunotherapies

Allogeneic cellular immunotherapies hold a great promise for cancer treatment owing to their potential cost-effectiveness, scalability and on-demand availability. However, immune rejection of adoptively transferred allogeneic T and natural killer (NK) cells is a substantial obstacle to achieving clinical responses that are comparable to responses obtained with current autologous chimeric antigen receptor T cell therapies. In this Perspective, we discuss strategies to confer cell-intrinsic, immune-evasive properties to allogeneic T cells and NK cells in order to prevent or delay their immune rejection, thereby widening the therapeutic window. We discuss how common viral and cancer immune escape mechanisms can serve as a blueprint for improving the persistence of off-the-shelf allogeneic cell therapies. The prospects of harnessing genome editing and synthetic biology to design cell-based precision immunotherapies extend beyond programming target specificities and require careful consideration of innate and adaptive responses in the recipient that may curtail the biodistribution, in vivo expansion and persistence of cellular therapeutics.

Delayed graft rejection in autoimmune islet transplantation via biomaterial immunotherapy

The induction of operational immune tolerance is a major goal in beta-cell replacement strategies for the treatment of type 1 diabetes. Our group previously reported long-term efficacy via biomaterial-mediated programmed death ligand 1 (PD-L1) immunotherapy in islet allografts in nonautoimmune models. In this study, we evaluated autoimmune recurrence and allograft rejection during islet transplantation in spontaneous nonobese diabetic (NOD) mice. Graft survival and metabolic function were significantly prolonged over 60 days in recipients of syngeneic islets receiving the biomaterial-delivered immunotherapy, but not in control animals. The biomaterial-mediated PD-L1 immunotherapy resulted in delayed allograft rejection in diabetic NOD mice compared with controls. Discrimination between responders and nonresponders was attributed to the enriched presence of CD206+ program death 1+ macrophages and exhausted signatures in the cytotoxic T cell compartment in the local graft microenvironment. Notably, draining lymph nodes had similar remodeling in innate and adaptive immune cell populations. This work establishes that our biomaterial platform for PD-L1 delivery can modulate immune responses to transplanted islets in diabetic NOD mice and, thus, can provide a platform for the development of immunologic strategies to curb the allo- and autoimmune processes in beta-cell transplant recipients.

Genetic ablation of adhesion ligands averts rejection of allogeneic immune cells

Allogeneic cell therapies hold promise for broad clinical implementation, but face limitations due to potential rejection by the recipient immune system. Silencing of beta-2-microglobulin ( B2M ) expression is commonly employed to evade T cell-mediated rejection, although absence of B2M triggers missing-self responses by recipient natural killer (NK) cells. Here, we demonstrate that deletion of the adhesion ligands CD54 and CD58 on targets cells robustly dampens NK cell reactivity across all sub-populations. Genetic deletion of CD54 and CD58 in B2M -deficient allogeneic chimeric antigen receptor (CAR) T and multi-edited induced pluripotent stem cell (iPSC)-derived NK cells reduces their susceptibility to rejection by NK cells in vitro and in vivo without affecting their anti-tumor effector potential. Thus, these data suggest that genetic ablation of adhesion ligands effectively alleviates rejection of allogeneic immune cells for immunotherapy.

Hydrolytic hydrogels tune mesenchymal stem cell persistence and immunomodulation for enhanced diabetic cutaneous wound healing

Diabetes is associated with an altered global inflammatory state with impaired wound healing. Mesenchymal stem/stromal cells (MSC) are being explored for treatment of diabetic cutaneous wounds due to their regenerative properties. These cells are commonly delivered by injection, but the need to prolong the retention of MSC at sites of injury has spurred the development of biomaterial-based MSC delivery vehicles. However, controlling biomaterial degradation rates in vivo remains a therapeutic-limiting challenge. Here, we utilize hydrolytically degradable ester linkages to engineer synthetic hydrogels with tunable in vivo degradation kinetics for temporally controlled delivery of MSC. In vivo hydrogel degradation rate can be controlled by altering the ratio of ester to amide linkages in the hydrogel macromers. These hydrolytic hydrogels degrade at rates that enable unencumbered cutaneous wound healing, while enhancing the local persistence MSC compared to widely used protease-degradable hydrogels. Furthermore, hydrogel-based delivery of MSC modulates local immune responses and enhances cutaneous wound repair in diabetic mice. This study introduces a simple strategy for engineering tunable degradation modalities into synthetic biomaterials, overcoming a key barrier to their use as cell delivery vehicles.

Combinatorial treatment rescues tumour-microenvironment-mediated attenuation of MALT1 inhibitors in B-cell lymphomas

Activated B-cell-like diffuse large B-cell lymphomas (ABC-DLBCLs) are characterized by constitutive activation of nuclear factor κB driven by the B-cell receptor (BCR) and Toll-like receptor (TLR) pathways. However, BCR-pathway-targeted therapies have limited impact on DLBCLs. Here we used >1,100 DLBCL patient samples to determine immune and extracellular matrix cues in the lymphoid tumour microenvironment (Ly-TME) and built representative synthetic-hydrogel-based B-cell-lymphoma organoids accordingly. We demonstrate that Ly-TME cellular and biophysical factors amplify the BCR-MYD88-TLR9 multiprotein supercomplex and induce cooperative signalling pathways in ABC-DLBCL cells, which reduce the efficacy of compounds targeting the BCR pathway members Bruton tyrosine kinase and mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1). Combinatorial inhibition of multiple aberrant signalling pathways induced higher antitumour efficacy in lymphoid organoids and implanted ABC-DLBCL patient tumours in vivo. Our studies define the complex crosstalk between malignant ABC-DLBCL cells and Ly-TME, and provide rational combinatorial therapies that rescue Ly-TME-mediated attenuation of treatment response to MALT1 inhibitors.

Measuring for primary prevention: An online survey of local community perspectives on family and domestic violence in regional Australia

BACKGROUND

Family and domestic violence, encompassing diverse behaviours including physical, sexual, emotional and financial abuse, is endemic worldwide and has multiple adverse health and social consequences. Principal drivers include traditional gender values that disempower women. Changing these is a key prevention strategy. In Australia, high-quality national surveys provide data on public perspectives concerning family and domestic violence but may not capture community-level diversity. As part of a project for primary prevention family and domestic violence in outer regional Australia, our aims were to develop and administer a questionnaire-based survey suitable for the local community encompassing knowledge about, attitudes towards, and personal experiences of family and domestic violence, to describe and to investigate the theoretical (factor) structure and local socio-demographic predictors of responses, and to determine the extent to which the survey findings are locally distinctive.

METHODS

The online community survey for local residents (≥15 years), comprised items on respondents' sociodemographic characteristics plus questions abridged from pre-existing national instruments on knowledge about, attitudes towards, and personal experiences of family and domestic violence. Responses were rake-weighted to correct census-ascertained sample imbalance and investigated using exploratory factor analysis, with sociodemographic predictors determined using multiple linear regression and dominance analysis.

RESULTS

Among 914 respondents, males (27.0%), those from age-group extremes, and less-educated persons were underrepresented. Familiarity with diverse family and domestic violence behaviours was high among all subgroups. Poorer knowledge of the FDV behaviour continuum and attitudes supporting traditional gender roles and FDV were disproportionately evident among males, older respondents and those with lower education levels. Both the factor structure of extracted composite measures reflecting community perspectives and sociodemographic predictors of responses generally aligned with patterns evident in national data.

CONCLUSIONS

Local reinforcement of existing nationwide findings on community understanding of and attitudes towards family and domestic violence provides salience for targeted interventions.

Towards an Evidence-Based Model of Workplace Postvention

This instrumental case study explored what suicide postvention might offer workplaces using the example of a large metropolitan funeral company. A mixed methods approach was utilized to examine staff experiences with suicide bereavement funerals and responses to a bespoke postvention training package. Staff found funerals due to suicide difficult in terms of communication, engagement and emotionality. These challenges were commonly characterized by increased tension and concern. In the absence of a postvention informed approach, staff had developed individual ways to negotiate the identified challenges of this work. The introduction of a staff-informed postvention training package delivered improvements in staff confidence with communication, understanding and management of the impact of suicide bereavement, and increased willingness to share information about postvention services with families and mourners. The findings indicated that benefits of the training could be extended through organizational governance and integration of supports. The findings are used to inform a model of workplace postvention together with a methodology incorporating staff experience and organizational context.

Hydrolytically Degradable Microgels with Tunable Mechanical Properties Modulate the Host Immune Response

Hydrogel microparticles (microgels) are an attractive approach for therapeutic delivery because of their modularity, injectability, and enhanced integration with the host tissue. Multiple microgel fabrication strategies and chemistries have been implemented, yet manipulation of microgel degradability and its effect on in vivo tissue responses remains underexplored. Here, the authors report a facile method to synthesize microgels crosslinked with ester-containing junctions to afford tunable degradation kinetics. Monodisperse microgels of maleimide-functionalized poly(ethylene-glycol) are generated using droplet microfluidics crosslinked with thiol-terminated, ester-containing molecules. Tunable mechanics are achievable based on the ratio of degradable to nondegradable crosslinkers in the continuous phase. Degradation in an aqueous medium leads to microgel deformation based on swelling and a decrease in elastic modulus. Furthermore, degradation byproducts are cytocompatible and do not cause monocytic cell activation under noninflammatory conditions. These injectable microgels possess time-dependent degradation on the order of weeks in vivo. Lastly, the evaluation of tissue responses in a subcutaneous dorsal pocket shows a dynamic type-1 like immune response to the synthetic microgels, driven by interferon gamma (IFN-γ  ) expression, which can be moderated by tuning the degradation properties. Collectively, this study demonstrates the development of a hydrolytic microgel platform that can be adapted to desired host tissue immune responses.

High-Throughput On-Chip Human Mesenchymal Stromal Cell Potency Prediction

Human mesenchymal stromal cells (hMSCs) are a promising source for regenerative cell therapy. However, hMSC clinical use has been stymied by product variability across hMSC donors and manufacturing practices resulting in inconsistent clinical outcomes. The inability to predict hMSC clinical efficacy, or potency, is a major limitation for market penetration. Standard metrics of hMSC potency employ hMSCs and third-party immune cell co-cultures, however, these assays face translational challenges due to third-party donor variability and lack of scalability. While surrogate markers of hMSC potency have been suggested, none have yet had translational success. To address this, a high-throughput, scalable, low-cost, on-chip microfluidic potency assay is presented with improved functional predictive power and recapitulation of in vivo secretory responses compared to traditional approaches. Comparison of hMSC secretory responses to functional hMSC-medicated immune cell suppression demonstrates shortcomings of current surrogate potency markers and identifies on-chip microfluidic potency markers with improved functional predictive power compared to traditional planar methods. Furthermore, hMSC secretory performance achieved in the on-chip microfluidic system has improved similarity compared to an in vivo model. The results underscore the shortcomings of current culture practices and present a novel system with improved functional predictive power and hMSC physiological responses.

Macrophage phenotypes in tissue repair and the foreign body response: Implications for biomaterial-based regenerative medicine strategies

Macrophages are a highly heterogeneous and plastic population of cells that are crucial for tissue repair and regeneration. This has made macrophages a particularly attractive target for biomaterial-directed regenerative medicine strategies. However, macrophages also contribute to adverse inflammatory and fibrotic responses to implanted biomaterials, typically related to the foreign body response (FBR). The traditional model in the field asserts that the M2 macrophage phenotype is pro-regenerative and associated with positive wound healing outcomes, whereas the M1 phenotype is pro-inflammatory and associated with pathogenesis. However, recent studies indicate that both M1 and M2 macrophages play different, but equally vital, roles in promoting tissue repair. Furthermore, recent technological developments such as single-cell RNA sequencing have allowed for unprecedented insights into the heterogeneity within the myeloid compartment, related to activation state, niche, and ontogenetic origin. A better understanding of the phenotypic and functional characteristics of macrophages critical to tissue repair and FBR processes will allow for rational design of biomaterials to promote biomaterial-tissue integration and regeneration. In this review, we discuss the role of temporal and ontogenetic macrophage heterogeneity on tissue repair processes and the FBR and the potential implications for biomaterial-directed regenerative medicine applications. STATEMENT OF SIGNIFICANCE: This review outlines the contributions of different macrophage phenotypes to different phases of wound healing and angiogenesis. Pathological outcomes, such as chronic inflammation, fibrosis, and the foreign body response, related to disruption of the macrophage inflammation-resolution process are also discussed. We summarize recent insights into the vast heterogeneity of myeloid cells related to their niche, especially the biomaterial microenvironment, and ontogenetic origin. Additionally, we present a discussion on novel tools that allow for resolution of cellular heterogeneity at the single-cell level and how these can be used to build a better understanding of macrophage heterogeneity in the biomaterial immune microenvironment to better inform immunomodulatory biomaterial design.

Immunotherapy via PD-L1-presenting biomaterials leads to long-term islet graft survival

Antibody-mediated immune checkpoint blockade is a transformative immunotherapy for cancer. These same mechanisms can be repurposed for the control of destructive alloreactive immune responses in the transplantation setting. Here, we implement a synthetic biomaterial platform for the local delivery of a chimeric streptavidin/programmed cell death-1 (SA-PD-L1) protein to direct "reprogramming" of local immune responses to transplanted pancreatic islets. Controlled presentation of SA-PD-L1 on the surface of poly(ethylene glycol) microgels improves local retention of the immunomodulatory agent over 3 weeks in vivo. Furthermore, local induction of allograft acceptance is achieved in a murine model of diabetes only when receiving the SA-PD-L1-presenting biomaterial in combination with a brief rapamycin treatment. Immune characterization revealed an increase in T regulatory and anergic cells after SA-PD-L1-microgel delivery, which was distinct from naïve and biomaterial alone microenvironments. Engineering the local microenvironment via biomaterial delivery of checkpoint proteins has the potential to advance cell-based therapies, avoiding the need for systemic chronic immunosuppression.

Integrin-specific hydrogels modulate transplanted human bone marrow-derived mesenchymal stem cell survival, engraftment, and reparative activities

Stem cell therapies are limited by poor cell survival and engraftment. A hurdle to the use of materials for cell delivery is the lack of understanding of material properties that govern transplanted stem cell functionality. Here, we show that synthetic hydrogels presenting integrin-specific peptides enhance the survival, persistence, and osteo-reparative functions of human bone marrow-derived mesenchymal stem cells (hMSCs) transplanted in murine bone defects. Integrin-specific hydrogels regulate hMSC adhesion, paracrine signaling, and osteoblastic differentiation in vitro. Hydrogels presenting GFOGER, a peptide targeting α2β1 integrin, prolong hMSC survival and engraftment in a segmental bone defect and result in improved bone repair compared to other peptides. Integrin-specific hydrogels have diverse pleiotropic effects on hMSC reparative activities, modulating in vitro cytokine secretion and in vivo gene expression for effectors associated with inflammation, vascularization, and bone formation. These results demonstrate that integrin-specific hydrogels improve tissue healing by directing hMSC survival, engraftment, and reparative activities.

Lysostaphin and BMP-2 co-delivery reduces S. aureus infection and regenerates critical-sized segmental bone defects

Staphylococcus aureus is the most common pathogen associated with bacterial infections in orthopedic procedures. Infections often lead to implant failure and subsequent removal, motivating the development of bifunctional materials that both promote repair and prevent failure due to infection. Lysostaphin is an anti-staphylococcal enzyme resulting in bacterial lysis and biofilm reduction. Lysostaphin use is limited by the lack of effective delivery methods to provide sustained, high doses of enzyme to infection sites. We engineered a BMP-2-loaded lysostaphin-delivering hydrogel that simultaneously prevents S. aureus infection and repairs nonhealing segmental bone defects in the murine radius. Lysostaphin-delivering hydrogels eradicated S. aureus infection and resulted in mechanically competent bone. Cytokine and immune cell profiling demonstrated that lysostaphin-delivering hydrogels restored the local inflammatory environment to that of a sterile injury. These results show that BMP-2-loaded lysostaphin-delivering hydrogel therapy effectively eliminates S. aureus infection while simultaneously regenerating functional bone resulting in defect healing.

Guardianship and Predatory Crimes among Incapacitated Persons in Kentucky

Purpose: Guardianship is a legal process intended to aid incapacitated persons unable to fully care for themselves. Guardianship in the state of Kentucky ranges from total observation (24-hour care) to informal care (such as a group home) and also includes persons who are no longer being supervised but should be. One intent of guardianship includes preventing incapacitated persons from engaging in criminal acts. However, no research has been conducted on incapacitated persons currently in guardianship and the prevalence for committing predatory crimes such as murder, fire starting, or assault.Method: In this study, the authors examine guardianship supervision levels and predatory crimes in the state of Kentucky. Logistic regression analysis was used to determine the variables that significantly contributed to the model.Results: They find that unsupervised incapacitated persons are at higher odds of committing predatory crimes, leading to important policy recommendations for Kentucky guardians.

Three-dimensional collagen matrix induces a mechanosensitive invasive epithelial phenotype

A critical step in breast cancer progression is local tissue invasion, during which cells pass from the epithelial compartment to the stromal compartment. We recently showed that malignant leader cells can promote the invasion of otherwise non-invasive epithelial follower cells, but the effects of this induced-invasion phenomenon on follower cell phenotype remain unclear. Notably, this process can expose epithelial cells to the stromal extracellular matrix (ECM), which is distinct from the ECM within the normal epithelial microenvironment. Here, we used a 3D epithelial morphogenesis model in which cells were cultured in biochemically and mechanically defined matrices to examine matrix-mediated gene expression and the associated phenotypic response. We found that 3D collagen matrix promoted expression of mesenchymal genes including MT1-MMP, which was required for collagen-stimulated invasive behavior. Epithelial invasion required matrix anchorage as well as signaling through Src, PI3K, and Rac1, and increasingly stiff collagen promoted dispersive epithelial cell invasion. These results suggest that leader cell-facilitated access to the stromal ECM may trigger an invasive phenotype in follower epithelial cells that could enable them to actively participate in local tissue invasion.

Local extracellular matrix alignment directs cellular protrusion dynamics and migration through Rac1 and FAK

Cell migration within 3D interstitial microenvironments is sensitive to extracellular matrix (ECM) properties, but the mechanisms that regulate migration guidance by 3D matrix features remain unclear. To examine the mechanisms underlying the cell migration response to aligned ECM, which is prevalent at the tumor-stroma interface, we utilized time-lapse microscopy to compare the behavior of MDA-MB-231 breast adenocarcinoma cells within randomly organized and well-aligned 3D collagen ECM. We developed a novel experimental system in which cellular morphodynamics during initial 3D cell spreading served as a reductionist model for the complex process of matrix-directed 3D cell migration. Using this approach, we found that ECM alignment induced spatial anisotropy of cells' matrix probing by promoting protrusion frequency, persistence, and lengthening along the alignment axis and suppressing protrusion dynamics orthogonal to alignment. Preference for on-axis behaviors was dependent upon FAK and Rac1 signaling and translated across length and time scales such that cells within aligned ECM exhibited accelerated elongation, front-rear polarization, and migration relative to cells in random ECM. Together, these findings indicate that adhesive and protrusive signaling allow cells to respond to coordinated physical cues in the ECM, promoting migration efficiency and cell migration guidance by 3D matrix structure.

A prospective investigation of dietary patterns and internalizing and externalizing mental health problems in adolescents

Investigating protective and risk factors that influence mental health in young people is a high priority. While previous cross-sectional studies have reported associations between diet and mental health among adolescents, few prospective studies exist. The aim of this study was to examine prospective relationships between dietary patterns and mental health among adolescents participating in the Western Australian Pregnancy Cohort (Raine) Study. Self-report questionnaires were used to assess indicators of mental health (Youth Self-Report externalizing/internalizing T-scores) and Western and Healthy dietary patterns (identified using factor analysis) at 14 (2003-2005) and 17 years (2006-2008). Multivariate linear and logistic regression were used to assess relationships between dietary patterns and mental health. Complete data were available for 746 adolescents. In females only, the Western dietary pattern z-score at 14 years was positively associated with greater externalizing behaviors at 17 years (β = 1.91; 95% CI: 0.04, 3.78) and a greater odds of having clinically concerning externalizing behaviors at 17 years (OR = 1.90; 95% CI: 1.06, 3.41). No other statistically significant associations were observed. Overall our findings only lend partial support to a link between diet and mental health. We found it to be specific to females consuming a Western dietary pattern and to externalizing behaviors. Future research on dietary patterns and mental health needs to consider possible sex differences and distinguish between different mental health outcomes as well as between healthy and unhealthy dietary patterns.

Not Just “A Walking the Dog”: Dog Walking and Pet Play and Their Association with Recommended Physical Activity among Adolescents

Purpose.

To examine the role of pet play and dog walking in children's and adolescents' leisure time, and the relationship between these activities and physical activity.

Design.

The study design was observational.

Setting.

The study setting was metropolitan Perth and nonmetropolitan regions in Western Australia.

Subjects.

The study included 1097 primary school (mean age, 10.1 years; SD, 1.6 years) and 657 secondary school (mean age, 14.0 years; SD, 1.3 years) students.

Measures.

Validated measures of total physical activity, dog walking, and pet play activity (prevalence and time) were calculated.

Analysis.

Generalized linear models tested for differences between proportions, while adjusting for socioeconomic status, age, and school-level clustering.

Results.

Approximately one third of primary school and one quarter of secondary school students reported that they walked the dog at least once in the last week. Pet play was the most common play activity for primary and secondary school girls, and the second and third most popular play activity for secondary and primary school boys, respectively. Secondary school students who walked the dog or played with pets spent an average of 1 hour per week on each activity, and they were significantly more likely (p < .005) to meet national physical activity recommendations than secondary school students not reporting these activities.

Conclusion.

Given the significant proportion of young people who frequently engage in dog walking and pet play, and the high level of pet ownership in many Western countries, promotion of these activities to support young people's health is warranted.

Genotype-by-environment interaction of growth traits in rainbow trout (Oncorhynchus mykiss): a continental scale study

Rainbow trout is a globally important fish species for aquaculture. However, fish for most farms worldwide are produced by only a few breeding companies. Selection based solely on fish performance recorded at a nucleus may lead to lower-than-expected genetic gains in other production environments when genotype-by-environment (G × E) interaction exists. The aim was to quantify the magnitude of G × E interaction of growth traits (tagging weight; BWT, harvest weight; BWH, and growth rate; TGC) measured across 4 environments, located in 3 different continents, by estimating genetic correlations between environments. A total of 100 families, of at least 25 in size, were produced from the mating 58 sires and 100 dams. In total, 13,806 offspring were reared at the nucleus (selection environment) in Washington State (NUC) and in 3 other environments: a recirculating aquaculture system in Freshwater Institute (FI), West Virginia; a high-altitude farm in Peru (PE), and a cold-water farm in Germany (GER). To account for selection bias due to selective mortality, a multitrait multienvironment animal mixed model was applied to analyze the performance data in different environments as different traits. Genetic correlation (rg) of a trait measured in different environments and rg of different traits measured in different environments were estimated. The results show that heterogeneity of additive genetic variances was mainly found for BWH measured in FI and PE. Additive genetic coefficient of variation for BWH in NUC, FI, PE, and GER were 7.63, 8.36, 8.64, and 9.75, respectively. Genetic correlations between the same trait in different environments were low, indicating strong reranking (BWT: rg = 0.15 to 0.37, BWH: rg = 0.19 to 0.48, TGC: rg = 0.31 to 0.36) across environments. The rg between BWT in NUC and BWH in both FI (0.31) and GER (0.36) were positive, which was also found between BWT in NUC and TGC in both FI (0.10) and GER (0.20). However, rg were negative between BWT in NUC and both BWH (-0.06) and TGC (-0.20) in PE. Correction for selection bias resulted in higher additive genetic variances. In conclusion, strong G × E interaction was found for BWT, BWH, and TGC. Accounting for G × E interaction in the breeding program, either by using sib information from testing stations or environment-specific breeding programs, would increase genetic gains for environments that differ significantly from NUC.

Defining desired genetic gains for rainbow trout breeding objective using analytic hierarchy process

Distributing animals from a single breeding program to a global market may not satisfy all producers, as they may differ in market objectives and farming environments. Analytic hierarchy process (AHP) is used to estimate preferences, which can be aggregated to consensus preference values using weighted goal programming (WGP). The aim of this study was to use an AHP-WGP based approach to derive desired genetic gains for rainbow trout breeding and to study whether breeding trait preferences vary depending on commercial products and farming environments. Two questionnaires were sent out. Questionnaire-A (Q-A) was distributed to 178 farmers from 5 continents and used to collect information on commercial products and farming environments. In this questionnaire, farmers were asked to rank the 6 most important traits for genetic improvement from a list of 13 traits. Questionnaire B (Q-B) was sent to all farmers who responded to Q-A (53 in total). For Q-B, preferences of the 6 traits were obtained using pairwise comparison. Preference intensity was given to quantify (in % of a trait mean; G%) the degree to which 1 trait is preferred over the other. Individual preferences, social preferences, and consensus preferences (Con-P) were estimated using AHP and WGP. Desired gains were constructed by multiplying Con-P by G%. The analysis revealed that the 6 most important traits were thermal growth coefficient (TGC), survival (Surv), feed conversion ratio (FCR), condition factor (CF), fillet percentage (FIL%), and late maturation (LMat). Ranking of traits based on average Con-P values were Surv (0.271), FCR (0.246), TGC (0.246), LMat (0.090), FIL% (0.081), and CF (0.067). Corresponding desired genetic gains (in % of trait mean) were 1.63, 1.87, 1.67, 1.29, 0.06, and 0.33%, respectively. The results from Con-P values show that trait preferences may vary for different types of commercial production or farming environments. This study demonstrated that combination of AHP and WGP can be used to derive desired gains for a breeding program and to quantify differences due to variations market demand or production environment.

Analysis of the comparative effectiveness of 3 oral bisphosphonates in a large managed care organization: adherence, fracture rates, and all-cause cost

BACKGROUND

Despite widespread availability and use of oral bisphosphonates, fracture rates and associated medical costs are still high. Differences in fracture risk among these agents, if any, have not been quantified due to the lack of high-quality, head-to-head, randomized, controlled trials assessing this outcome. Randomized, placebo-controlled trials have shown that alendronate and risedronate reduce rates of both vertebral and nonvertebral fractures, whereas only reduction in vertebral fractures has been found for ibandronate.

OBJECTIVE

To determine if there were any differences among 3 oral bisphosphonates in adherence, total cost of care, and effectiveness in reducing fracture rates in a large managed care population.

METHODS

Administrative, longitudinal pharmacy and medical claims data were obtained from 14 geographically diverse health plans in the United States covering approximately 14 million members. Sampled members had at least 1 pharmacy claim for alendronate, risedronate, or ibandronate during the intake period (January 1, 2005, through October 31, 2007). The date of the first pharmacy claim for osteoporosis medications within the intake period was the index date. Members were followed for either 12, 24, or 36 months, depending on length of continuous health plan eligibility. Medication possession ratio (MPR) was measured using a total days supply that was calculated by multiplying the total quantity dispensed by the suggested days supply per unit of dispensing based on manufacturer-recommended dosing. For members who switched bisphosphonate strengths or medications, the estimated days supply was summed for all osteoporosis medications during the follow-up, including overlapping days supply. Outcomes included (a) the first incident fracture and percentages of members with at least 1 fracture after 6 months post-index; (b) the number of days from index to the first incident fracture, measured as time to event in Cox proportional hazards regression analysis; and (c) total all-cause health care costs (health plan allowed amount including member cost share).

RESULTS

A total of 45,939 members were included (n = 24,909 alendronate, n = 13,834 risedronate, n = 7,196 ibandronate). In the 12-month analysis, MPRs were comparable (means = 0.57-0.58) for the 3 medications. After 24 months, MPRs had dropped for all medications, but those of both alendronate (mean = 0.50, 95% CI = 0.49-0.50) and risedronate (mean = 0.50, 95% CI = 0.49-0.51) were slightly higher than that of ibandronate (mean = 0.47, 95% CI = 0.46-0.48). At 36 months, again the MPRs had dropped for all 3 medications (means = 0.44-0.47) but were similar. There were no statistically significant differences among agents in the percentages of subjects with at least 1 fracture at 12, 24, or 36 months (36-month rates: alendronate 4.41%, risedronate 4.38%, ibandronate 6.28%, P = 0.102). The numbers of subjects with fracture(s) per month of follow-up were 0.0020 for alendronate, 0.0021 for risedronate, and 0.0022 for ibandronate (P = 0.087 overall). However, after adjusting for member characteristics, alendronate users had a 12% lower risk of experiencing any incident fracture than ibandronate users (hazard ratio = 0.88, 95% CI = 0.78-0.99, P = 0.034) within the follow-up period. In the first 12 post-index months, ibandronate users had higher mean [SD] unadjusted total all-cause health care costs ($7,464 [$15,975]) compared with alendronate ($7,233 [$16,671]) and risedronate ($ 6,983 [$16,870], P less than 0.001 for both comparisons), differences of approximately $19 per month and $40 per month, respectively. The results of the unadjusted 24-month analysis were similar, but there were no significant cost differences at 36 months. Total cost differences for the 3 medication groups were nonsignificant at 12, 24, and 36 months after adjusting for member characteristics.

CONCLUSIONS

This retrospective analysis of an administrative claims database in a large managed care population showed similar rates of adherence and total adjusted all-cause health care costs for alendronate, risedronate, and ibandronate. Absolute unadjusted rates of fracture were small and did not significantly differ among agents, but after controlling for differences in member characteristics, the risk of fracture was 12% lower for alendronate users than for ibandronate users.

Thirty-day mortality of Clostridium difficile infection in a UK National Health Service Foundation Trust between 2002 and 2008

Few standardised data are available on mortality rates in patients with Clostridium difficile infection (CDI). The literature often reports 'attributable' mortality or cannot be universally applied. We aimed to investigate the pattern and trends in all-cause mortality in a large unselected cohort of patients affected by CDI. This was done by means of a retrospective cohort study between 2002 and 2008 of all patients with positive stool toxin tests indicating CDI in one National Health Service (NHS) Trust, comprising three general hospitals and seven community hospitals. Vital status of the patients was determined from two sources. In total, 2571 patients with a first episode of CDI were identified (1638 females; median age 82.1 years). Cumulative mortality at 7 days, 14 days, 30 days and 1 year was 13.4%, 20.8%, 32.5% and 58.7%, respectively. There was no significant difference in mortality between sex, year of diagnosis or hospital site. Mortality at 30 days increased incrementally from 3.4% in those aged <40 years to 41% in those >90 years. Mortality rates were significantly higher than reported by previous studies but were remarkably consistent over the time period and between different hospitals within the Trust. Prognosis falls with increasing age, and the age of this cohort may explain the high 30-day absolute mortality. CDI infection is associated with high early mortality. To reduce mortality, new interventions need to be introduced soon after diagnosis. There is a need for standardised outcome data for CDI.

Select Listeria monocytogenes subtypes commonly found in foods carry distinct nonsense mutations in inlA, leading to expression of truncated and secreted internalin A, and are associated with a reduced invasion phenotype for human intestinal epithelial cells

The surface protein internalin A (InlA) contributes to the invasion of human intestinal epithelial cells by Listeria monocytogenes. Screening of L. monocytogenes strains isolated from human clinical cases (n=46), foods (n=118), and healthy animals (n=58) in the United States revealed mutations in inlA leading to premature stop codons (PMSCs) in L. monocytogenes ribotypes DUP-1052A and DUP-16635A (PMSC mutation type 1), DUP-1025A and DUP-1031A (PMSC mutation type 2), and DUP-1046B and DUP-1062A (PMSC mutation type 3). While all DUP-1046B, DUP-1062A, DUP-16635A, and DUP-1031A isolates (n=76) contained inlA PMSCs, ribotypes DUP-1052A and DUP-1025A (n=72) contained isolates with and without inlA PMSCs. Western immunoblotting showed that all three inlA PMSCs result in the production of truncated and secreted InlA. Searches of the Pathogen Tracker database, which contains subtype and source information for more than 5,000 L. monocytogenes isolates, revealed that the six ribotypes shown to contain isolates with inlA PMSCs were overall more commonly isolated from foods than from human listeriosis cases. L. monocytogenes strains carrying inlA PMSCs also showed significantly (P=0.0004) reduced invasion of Caco-2 cells compared to isolates with homologous 3' inlA sequences without PMSCs. Invasion assays with an isogenic PMSC mutant further supported the observation that inlA PMSCs lead to reduced invasion of Caco-2 cells. Our data show that specific L. monocytogenes subtypes which are common among U.S. food isolates but rare among human listeriosis isolates carry inlA mutations that are associated with, and possibly at least partially responsible for, an attenuated invasion phenotype.

Variation in clinician recommendations for multiple injections during adoption of inactivated polio vaccine

OBJECTIVES

To describe variation in clinician recommendations for multiple injections during the adoption of inactivated poliovirus vaccine (IPV) in 2 large health maintenance organizations (HMOs), and to test the hypothesis that variation in recommendations would be associated with variation in immunization coverage rates.

DESIGN

Cross-sectional study based on a survey of clinician practices 1 year after IPV was recommended and computerized immunization data from these clinicians' patients. STUDY SETTINGS: Two large West Coast HMOs: Kaiser Permanente in Northern California and Group Health Cooperative of Puget Sound.

OUTCOME MEASURES

Immunization status of 8-month-olds and 24-month-olds cared for by the clinicians during the study.

RESULTS

More clinicians at Group Health (82%), where a central guideline was issued, had adopted the IPV/oral poliovirus vaccine (OPV) sequential schedule than at Kaiser (65%), where no central guideline was issued. Clinicians at both HMOs said that if multiple injections fell due at a visit and they elected to defer some vaccines, they would be most likely to defer the hepatitis B vaccine (HBV) for infants (40%). At Kaiser, IPV users were more likely than OPV users to recommend the first HBV at birth (64% vs 28%) or if they did not, to defer the third HBV to 8 months or later (62% vs 39%). In multivariate analyses, patients whose clinicians used IPV were as likely to be fully immunized at 8 months old as those whose clinicians used all OPV. At Kaiser, where there was variability in the maximum number of injections clinicians recommended at infant visits, providers who routinely recommended 3 or 4 injections at a visit had similar immunization coverage rates as those who recommended 1 or 2. At both HMOs, clinicians who strongly recommended all possible injections at a visit had higher immunization coverage rates at 8 months than those who offered parents the choice of deferring some vaccines to a subsequent visit (at Kaiser, odds ratio [OR]: 1.2; 95% confidence interval [CI]: 1.0-1.5; at Group Health, OR: 1.8; 95% CI: 1.1-2.8).

CONCLUSIONS

Neither IPV adoption nor the use of multiple injections at infant visits were associated with reductions in immunization coverage. However, at the HMO without centralized immunization guidelines, IPV adoption was associated with changes in the timing of the first and third HBV. Clinical policymakers should continue to monitor practice variation as future vaccines are added to the infant immunization schedule.

Nurse practitioners: a comparison of rural-urban practice patterns and willingness to serve in underserved areas

PURPOSE

To determine nurse practitioners' (NPs) practice patterns and willingness to practice in underserved areas in both rural and urban settings in a largely rural state.

DATA SOURCES

A census of all NPs holding a Pennsylvania license and providing addresses in Pennsylvania or one of the contiguous states was conducted in 1996. The ZIP codes of practice sites were matched with 1990 census data.

CONCLUSIONS

Nurse practitioners in rural areas are more likely than their urban counterparts to provide primary care in primary care practice settings, they see more patients per week, and they are more likely to be the principal provider of care for a higher percentage of their patients. Experience with managed care contracts is greater for urban NPs as is their willingness to practice in urban underserved areas. Rural NPs were more willing to practice in rural underserved areas than their urban counterparts.

IMPLICATIONS FOR PRACTICE

Access to primary care continues to be a concern in rural areas. The increasing market penetration of managed care and the deficit of primary care providers in rural environments may lead to increased opportunities for NPs in the rural health care delivery system.

The hidden costs of infant vaccination

Combination vaccines to minimize injections required for infant vaccination, and new vaccines with improved safety profiles, will pose increasingly complex choices for vaccine purchasers in the future. How much of a premium to pay for such vaccines might be determined by taking into account (1) the psychological burden of multiple injections during a single clinic visit, and the costs of any additional visits to minimize these, and (2) the medical, work-loss, and incidental costs of common vaccine-associated symptoms. This cross-sectional survey included randomly-selected parents of 1-8-month-old infants who received vaccines in a Northern California health maintenance organization (HMO) in 1997. Interviewers called parents 14 days after the infant's vaccination to administer a 10-minute closed-ended interview in English or Spanish. Parents were asked about infant symptoms after vaccination, their preferences regarding multiple injections and their (theoretical) willingness to pay to reduce the number of injections their infant would receive, or to avoid the adverse symptoms experienced. Among 1769 eligible infants, interviews were completed with parents of 1657 (93%). The psychological cost of multiple injections was estimated by the willingness of parents to pay a median of $25 to reduce injections from 4 to 3, $25 from 3 to 2, and $50 from 2 to 1. Vaccine-associated symptoms caused mean costs of $42 in medical utilization and $192 in work-loss among the families who experienced those events (Ns=62 and 35, respectively). When averaged among all 1657 study infants, vaccine-associated symptoms after the index vaccination visit resulted in $2.91 in medical utilization, $4.05 in work-loss, and $0.74 in direct nonmedical costs, yielding total financial costs of $7.70. Parents of infants who had vaccine-associated symptoms said they would have paid a median of $50 to avoid these symptoms. Fever and fussiness were associated in logistic regression analysis with a two-fold increase in the odds of medical utilization, and fever with more than a three-fold increase in work loss. We conclude that multiple injections during a single clinic visit entail psychological costs. The psychological costs of vaccine-associated symptoms, as measured by willingness-to-pay methods, are higher than those resulting from multiple injections. The financial costs of medical utilization and work-loss resulting from common vaccine-associated symptoms are non-negligible and should be incorporated in economic analyses.

A rural-urban comparison of patterns of physician assistant practice

Access to primary care continues to be a concern in rural areas. The deficit of primary care providers in rural environments has the potential to increase the role of physician assistants (PAs) in the system of rural health care delivery. Little is known about the conditions, sites, and patterns of practice of PAs and their distribution in Pennsylvania, the state with the largest rural population. To learn more about these providers in rural and urban settings and their willingness to practice in underserved areas, the author conducted a census of all PAs who hold a Pennsylvania license. Survey results revealed significant rural-urban differences in socioeconomic, demographic, and practice profile parameters. Providers in rural areas are more likely than urban counterparts to practice primary care in a primary care practice setting; see more patients per week; and are the principal provider of care for a higher percentage of their patients. Experience with managed care is greater for urban PAs. A rural PA is more likely than an urban PA to practice in an underserved area. For both rural and urban PAs who practice primary care, significant differences were noted in their willingness to practice in a rural underserved area, compared to PAs who do not practice primary care.

Obstacle crossing in subjects with stroke

OBJECTIVE

To study the ability of subjects with stroke to successfully step over an obstacle during ambulation.

SETTING

A geriatric rehabilitation unit in a tertiary referral hospital.

SUBJECTS

Twenty-four inpatients with stroke (median time poststroke 27 days, interquartile range 21 to 44.5 days) able to walk 10 m unassisted without walking aids; also, 22 healthy subjects.

METHOD

Subjects were required to step over obstacles of various heights and widths, ranging from 1cm to 8cm. A fail was scored if the obstacle was contacted by either lower limb or if assistance or upper limb support was required. The choice of leading limb and the presence of visual deficits and neglect were also recorded in the stroke subjects. Subjects were tested on two occasions.

RESULTS

Significantly more fails were recorded for stroke subjects, with 13 subjects failing at least once. No preference was shown for leading either with the affected or with the unaffected leg. Stroke subjects showed inconsistent performance over the two testing sessions.

CONCLUSION

The ability to negotiate obstacles was compromised and inconsistent in stroke subjects undergoing inpatient rehabilitation. This suggests that gait safety in this population remains threatened.

An assessment of practice support and continuing medical education needs of rural Pennsylvania family physicians

Family physicians provide the greatest proportion of care in rural communities. Yet, the number of physicians choosing family practice and rural practice has continued to decline. Undesirable aspects of rural practice, such as professional isolation and a lack of or inadequate resources, are assumed to be associated with this decline. This article reports on the practice support and continuing medical education needs of rural family physicians. A mail survey was conducted in 1993 on a purposive sample of family physicians in 39 of 67 rural-designated or urban Pennsylvania counties with low population densities. The physicians identified needs that included patient education materials and programs, community health promotion, federal regulation updates, technical assistance with computers and business management, database software and a videotape lending library, a drug hotline, and mini-fellowships on clinical skill development. A majority of respondents were willing to participate in clinical educational experiences for students and residents. Some physicians indicated a lack of interest in access to information through telecommunications, e.g., video conference referrals and consultations. Overall, findings revealed that family physicians need and are receptive to a variety of practice support and continuing education programs. A practice support program coupled with policy coordination among public and private organizations is likely to lessen complaints by rural primary care physicians.

Clinical outcomes and maternal perceptions of an updated model of perinatal care

BACKGROUND

Postpartum hospital stays seem likely to remain limited even under new laws which mandate that insurers cover 48-hour hospitalization after uncomplicated delivery. Clinicians, who are increasingly practicing in capitated arrangements, need better information to maximize clinical benefit to mothers and newborns using finite resources. OBJECTIVE AND INTERVENTIONS: This study's aim was to evaluate the clinical outcomes, patient perceptions, and costs of a revised model of perinatal care services. In this model, a new postpartum care center was established for routine follow-up of newborns within 48 hours after hospital discharge, educational efforts were shifted from the postpartum hospitalization to the prenatal period, and lactation consultant hours were increased.

DESIGN AND PARTICIPANTS

Controlled, nonrandomized (double cohort) study that compared mothers and newborns with hospital stays of 48 hours or less during the Baseline Care (preintervention) study period (N = 344) with those under the Revised Care (postintervention) study period (N = 456).

SETTING

The Hayward, California, medical center of Kaiser Permanente, a nonprofit health maintenance organization.

DATA COLLECTION

Telephone interviews were attempted with all mothers 3 weeks after delivery. Data on rehospitalizations, emergency department (ED) and clinic visits, and costs during the first 14 postpartum days were collected from computerized databases and chart review.

OUTCOME MEASURES

The combined clinical outcome was defined as any undesirable health event, including rehospitalization, an ED visit, or an urgent clinic visit by either the mother or newborn within the first 14 days postpartum, or breastfeeding discontinuation within the first 21 days postpartum. Maternal satisfaction and costs were also studied.

RESULTS

Of 876 attempted interviews, 800 were completed (91%). Analyses were adjusted for age, race, education, parity, breastfeeding experience, and other relevant variables. Among the interviewed mother-newborn pairs, 45% in the Revised Care group experienced the combined clinical outcome, compared with 52% in the Baseline Care group. Newborns in the Revised Care group (29%) were significantly less likely to make urgent clinic visits during the first 14 days of life than those in the Baseline Care group (36%). There were no differences between groups in newborn ED visits or rehospitalizations, maternal clinical outcomes, or breastfeeding continuation. Mothers in the Revised Care group expressed higher satisfaction with the newborn's care, the amount of information they received about newborn care and breastfeeding, and the amount of help they received with breastfeeding. Planned hospital care, planned follow-up visits, and unplanned care costs decreased by $149 per delivery, while the new prenatal class and increased lactation consultant services cost $58 per delivery, for an estimated overall reduction in cost.

CONCLUSIONS

We conclude that the revised model of perinatal care in this health maintenance organization medical center improved clinical outcomes and maternal satisfaction for low-risk mothers and newborns without increasing costs.

Outpatient management practices associated with reduced risk of pediatric asthma hospitalization and emergency department visits

OBJECTIVES

Effective outpatient care is believed to prevent hospitalization and emergency department (ED) visits resulting from childhood asthma. The aim of this study was to suggest priority areas for intervention by identifying outpatient management practices associated with the risk of these adverse outcomes in a large population.

METHODS

This case-control study included children aged 0 to 14 years with asthma who were members of a regional health maintenance organization. Cases were children undergoing either a hospitalization or an ED visit for asthma during the study period. Control subjects were children with asthma without a hospitalization or an ED visit during the study period who were matched to patients on age, gender, and number of asthma-related hospitalizations in the past 24 months. Data on provider and parent asthma management practices were collected using chart review, closed-ended telephone interviews with parents, and computerized use databases. Multivariate analyses were conducted using conditional logistic regression models.

RESULTS

Data were collected on 508 cases and 990 control subjects. A total of 43% of cases were reported by their parents to have moderately severe or severe asthma, compared with 20% of control subjects. Parents of cases with hospitalization were less likely than control subjects to have a written asthma management plan (44% vs 51%) and to report washing bedsheets in hot water at least twice a month (77% vs 86%). Cases with hospitalization were more likely to have a nebulizer (74% vs 56%). In the final multivariate model, race/ethnicity was not associated with having had either a hospitalization or an ED visit, as was lower socioeconomic status. Having a written asthma management plan [odds ratio (OR): 0.54; 95% confidence interval (CI): 0.30, 0.99] and washing bedsheets in hot water at least twice a month (OR: 0.45; 95% CI: 0.21, 0.94) were associated with reduced odds of hospitalization. Having a written asthma management plan (OR: 0.45; 95% CI: 0.27, 0.76) and starting or increasing medications at the onset of a cold or flu were associated with reduced odds of making an ED visit.

CONCLUSIONS

Practices that support early intervention for asthma flare-ups by parents at home, particularly written management plans, are strongly associated with reduced risk of adverse outcomes among children with asthma.

Mosaic partial trisomy 17 due to a ring chromosome identified by fluorescence in situ hybridisation

We report on a 3-year-old-girl with mosaic partial trisomy 17 due to an additional ring chromosome 17 in 13% of cells analysed. This was identified by fluorescence in situ hybridisation (FISH) using a whole chromosome 17 specific paint as well as probes specific for the Smith-Magenis and Miller-Dieker regions of chromosome 17p. This girl showed mild developmental delay with subtle facial and other minor abnormalities including single palmar creases, generalised joint laxity, and a scoliosis.

The use of early enteral nutrition in abdominal trauma

Patients who sustain abdominal trauma become hypermetabolic and require aggressive utilization of early enteral nutrition. The purpose of this article is to discuss the physiology of the gut as it relates to the development of septic sequelae and the role of early enteral nutrition in decreasing septic complications based upon the findings of previously published research. The research clearly supports that there are many benefits associated with the initiation of early enteral nutrition in this patient population.

Occlusion edge blur: a cue to relative visual depth

We studied whether the blur/sharpness of an occlusion boundary between a sharply focused surface and a blurred surface is used as a relative depth cue. Observers judged relative depth in pairs of images that differed only in the blurriness of the common boundary between two adjoining texture regions, one blurred and one sharply focused. Two experiments were conducted; in both, observers consistently used the blur of the boundary as a cue to relative depth. However, the strength of the cue, relative to other cues, varied across observers. The occlusion edge blur cue can resolve the near/far ambiguity inherent in depth-from-focus computations.

Factors influencing retention of rural Pennsylvania family physicians

BACKGROUND

Rural areas suffer from a lack of primary care physicians. Efforts to retain physicians should focus on modifying or changing attributes of rural practice that are considered by physicians to be undesirable. A practice support outreach program (PSOP) is one initiative expected to enhance retention in rural areas by addressing negative aspects of rural practice. The purpose of this study was to assess factors related to satisfaction and retention of family physicians to develop and implement a PSOP in rural areas of Pennsylvania.

METHOD

In 1993 a mail survey was conducted on a convenience sample of 398 family physicians practicing in 39 counties in Pennsylvania.

RESULTS

Twenty percent of respondents were considering leaving rural practice. Bivariate analyses indicated that professional isolation, lower reimbursements, and sharing on-call with only 1 other physician were associated with physician's reasons for considering leaving rural practice. A multiple logistic regression revealed that sharing on-call rotation with only 1 other physician and having a solo practice were significant influences in considering leaving rural practice.

CONCLUSIONS

Findings suggest support strategies that minimize perceptions of professional isolation and policy efforts that address reimbursement differentials and compliance issues are needed to minimize many complaints of rural family physicians.

Severe microphthalmia, diaphragmatic hernia and Fallot's tetralogy associated with a chromosome 1;15 translocation

A 9-year-old boy with multiple abnormalities including severe bilateral microphthalmia, diaphragmatic hernia and Fallot's tetralogy is presented. He has also been shown to have an apparently balanced de novo reciprocal translocation, 46,XY,t(1;15)(q41;q21.2), which suggests that one of those breakpoints may be the locus for a gene which is important in morphogenesis.

Could bradykinesia in Parkinson's disease simply be compensation?

Even normal movements can be slow and hesitant. To distinguish between bradykinesia and the simple slow inefficiency sometimes seen in normal movement, we matched the movement durations of 12 patients with Parkinson's disease (PD) and 12 age-matched controls and examined end-point accuracy, number of submovements, force inefficiency, and relative duration of acceleration and deceleration phases of movement. Subjects used an electronic pen which sampled pen-tip position at 200 Hz, and performed a sequence of drawing movements to nine targets (0.5, 1, or 2 cm diameter) upon a WACOM SD420 graphics tablet. Patients could be trained to move at the preferred speed of controls (and vice versa). When moving at the same fast speed as controls, patient's movements were less accurate (increased end-point spread). Even when moving at their own preferred speed, patients' movements were less efficient (more submovements, more zero crossings in acceleration function) than controls moving at the same speed. If bradykinesia simply reflected increased caution and visual guidance, we would expect patients to exhibit prolonged decelerative phases of movement associated with terminal guidance. However, patients consistently required prolonged accelerative phases of movement, suggesting that there was a problem in generating appropriate movement forces to produce the required end-point accuracy. It is hypothesised that bradykinesia is not simply a compensation for defective preparatory processes, but may reflect a defective internal cue in PD which disrupts and impairs the outflow of motor responses.

Inaccuracy and instability of sequential movements in Parkinson's disease

Animal studies suggest that the basal ganglia (BG) provide internal cues to trigger submovements in a movement sequence, with Parkinson's disease (PD) involving a deficiency in this cueing mechanism. However, it is not clear why defective internal cues can produce slow movements, or the extent to which slow movements are indeed the basic movement abnormality or are perhaps a compensatory mechanism for some other primary deficit. In this study we examined a number of the kinematic indices of matched fast movements between PD patients and age-matched controls, performed with and without reductions in visual cues for guidance, in order to delineate the relationship between the internal cue and the kinematic characteristics of these movements. Fourteen patients with PD, and their matched controls, used an electronic pen, which sampled pen-tip position at 200 Hz, and performed a sequence of drawing movements to nine targets upon a WACOM SD 420 graphics tablet. Subjects were trained to perform the movement sequence at a fast speed and were then required to perform the same movement at the same speed with reduced visual cues. Kinematic analysis indicated that, when visual cues were reduced, movements of PD patients became spatially and temporally unstable as they were progressively performed down the sequence. The instability was associated with an abnormal force profile increase in peak movement velocity and target overshoot, which became additive as the submovements progressed. We suggest that defective cue production is the basic deficit in parkinsonian hypokinesia. The defective cue leads to problems synchronising preparatory activity, which then results in abnormalities in movement forces which are characterised by unpredictable and inaccurate movement endpoints. When movements are strung together in a sequence the inaccuracy is additive leading to motor instability.

Are double translocations double trouble?

Double translocation heterozygotes are rare, but need not necessarily pose more of a counselling problem than single reciprocal translocation heterozygotes. Nine cases of double translocation are presented, together with a review of the few reports published to date. An attempt is made to provide simple counselling guidelines in the assessment of the risk of producing a liveborn abnormal child. This is not based on theoretical considerations of segregation patterns, but extrapolated from what is known empirically about the viable segregation patterns in carriers of single reciprocal translocations. It assumes that there is no interference with the independent assortment of the two separate exchanges, unless a common participating chromosome is involved. The possibility of an interchromosomal effect has not been taken into consideration.

Protection against experimental Pseudomonas aeruginosa infection in mice by active immunization with exotoxin A toxoids

The immunoprophylactic effect of chemically inactivated Pseudomonas aeruginosa exotoxin A in experimental pseudomonas infections was studied. Exotoxin A toxoids were prepared by Formalin (f-TXD) or glutaraldehyde (g-TXD) treatment. Immunization of mice with three or four doses (10 micrograms each) of f-TXD and the synthetic adjuvant N-acetylmuramyl-L-alanyl-D-isoglutamine (50 micrograms) induced high levels of antiexotoxin A antibodies as measured by passive hemagglutination assay and enzyme-linked immunosorbent assay. Immunization with toxoid alone did not elicit antitoxin. A significant increase in survival time and survival rate (P less than 0.01) was seen in immunized (f-TXD) and in burned and infected mice (50 to 85%) as compared with control mice immunized with formalinized bovine serum albumin (6 to 20%). Virtually 100% survival was obtained when preinfection immunization weas combined with single-dose gentamicin treatment within 24 h of infection. Immunization with g-TXD increased survival time (P less than 0.01) but did not consistently increase survival rate, and the results were not as satisfactory as those with formalinized exotoxin. The data presented indicate that active immunization with formalinized exotoxin A toxoid and adjuvant induced protective immunity to various degrees against infections in mice and could be potentially useful in prophylaxis of P. aeruginosa infections.