Cross-validation of the RT-QuIC assay for the antemortem detection of chronic wasting disease in elk

Chronic wasting disease is a progressively fatal, horizontally transmissible prion disease affecting several members of the cervid species. Conventional diagnosis relies on ELISA or IHC evaluation using tissues collected post-mortem; however, recent research has focused on newly developed amplification techniques using samples collected antemortem. The present study sought to cross-validate the real-time quaking-induced conversion assay (RT-QuIC) evaluation of rectal biopsies collected from an elk herd with endemic CWD, assessing both binary positive/negative test results as well as relative rates of amplification between laboratories. We found that results were correlative in both categories across all laboratories performing RT-QuIC, as well as to conventional IHC performed at a national reference laboratory. A significantly higher number of positive samples were identified using RT-QuIC, with results seemingly unhindered by low follicle counts. These findings support the continued development and implementation of amplification assays in the diagnosis of prion diseases of veterinary importance, targeting not just antemortem sampling strategies, but post-mortem testing approaches as well.

Attitudinal barriers to participation in oncology clinical trials: factor analysis and correlates of barriers

Patient participation in cancer clinical trials is low. Little is known about attitudinal barriers to participation, particularly among patients who may be offered a trial during an imminent initial oncology consult. The aims of the present study were to confirm the presence of proposed subscales of a recently developed cancer clinical trial attitudinal barriers measure, describe the most common cancer clinical trials attitudinal barriers, and evaluate socio-demographic, medical and financial factors associated with attitudinal barriers. A total of 1256 patients completed a survey assessing demographic factors, perceived financial burden, prior trial participation and attitudinal barriers to clinical trials participation. Results of a factor analysis did not confirm the presence of the proposed four attitudinal barriers subscale/factors. Rather, a single factor represented the best fit to the data. The most highly-rated barriers were fear of side-effects, worry about health insurance and efficacy concerns. Results suggested that less educated patients, patients with non-metastatic disease, patients with no previous oncology clinical trial participation, and patients reporting greater perceived financial burden from cancer care were associated with higher barriers. These patients may need extra attention in terms of decisional support. Overall, patients with fewer personal resources (education, financial issues) report more attitudinal barriers and should be targeted for additional decisional support.

The relationships among knowledge, self-efficacy, preparedness, decisional conflict, and decisions to participate in a cancer clinical trial

BACKGROUND

Cancer clinical trials (CCTs) are important tools in the development of improved cancer therapies; yet, participation is low. Key psychosocial barriers exist that appear to impact a patient's decision to participate. Little is known about the relationship among knowledge, self-efficacy, preparation, decisional conflict, and patient decisions to take part in CCTs.

OBJECTIVE

The purpose of this study was to determine if preparation for consideration of a CCT as a treatment option mediates the relationship between knowledge, self-efficacy, and decisional conflict. We also explored whether lower levels of decisional conflict are associated with greater likelihood of CCT enrollment.

METHOD

In a pre-post test intervention study, cancer patients (N = 105) were recruited before their initial consultation with a medical oncologist. A brief educational intervention was provided for all patients. Patient self-report survey responses assessed knowledge, self-efficacy, preparation for clinical trial participation, decisional conflict, and clinical trial participation.

RESULTS

Preparation was found to mediate the relationship between self-efficacy and decisional conflict (p = 0.003 for a test of the indirect mediational pathway for the decisional conflict total score). Preparation had a more limited role in mediating the effect of knowledge on decisional conflict. Further, preliminary evidence indicated that reduced decisional conflict was associated with increased clinical trial enrollment (p = 0.049).

CONCLUSIONS

When patients feel greater CCT self-efficacy and have more knowledge, they feel more prepared to make a CCT decision. Reduced decisional conflict, in turn, is associated with the decision to enroll in a clinical trial. Our results suggest that preparation for decision-making should be a target of future interventions to improve participation in CCTs.

Anxiety and depression in mothers of children undergoing bone marrow transplant: symptom prevalence and use of the Beck depression and Beck anxiety inventories as screening instruments

This study examined anxiety and depressive symptoms among 115 mothers of children undergoing bone marrow transplant and evaluated the ability of the Beck Anxiety Inventory (BAI; A. T. Beck, N. Epstein, et al., 1988) and the Beck Depression Inventory (BDI; A. T. Beck, 1978) to serve as screening tools for assessing generalized anxiety disorder (GAD), panic disorder (PD), and major depressive disorder (MDD). Mothers with BAI or BDI scores greater than or equal to 14 were administered a structured clinical interview. An additional 20% was randomly selected for interview to determine whether the scale cutoff was an accurate screening method. Among the 64 mothers interviewed, 20% received at least I of the 3 diagnoses. Although the BAI did not demonstrate predictive accuracy in assessing GAD and PD, the BDI did in assessing MDD. The results suggest that a subset of mothers may have an anxiety or depressive disorder and that investigators should use caution before using the BAI as a screening instrument for anxiety disorder.

Measuring supportive and unsupportive responses during cancer treatment: a factor analytic assessment of the partner responses to cancer inventory

This study examined the psychometric structure of a measure of positive and negative spouse responses to individuals with cancer, the Partner Responses to Cancer Inventory (PRCI). The forty-eight items were either developed by the authors or adapted from the Inventory of Socially Supportive Behaviors. Seven a priori subscales of the PRCI, four positive support scales and three negative spouse behavior scales, were hypothesized. The instrument was administered to 304 cancer patients undergoing cancer treatment. Exploratory factor analyses yielded four factors that were subsequently confirmed by confirmatory factor analysis: (a) Emotional and Instrumental Support, (b) Cognitive Information and Guidance, (c) Encouraging Distancing and Self-Restraint, and (d) Criticism and Withdrawal. The measure satisfied standard criteria for internal consistency and construct validity, and thus may be useful for social support theory and research.

Intrusion, avoidance, and psychological distress among individuals with cancer

OBJECTIVE

The goal of the study was to examine the utility of Creamer's cognitive processing theory of trauma in a sample of individuals undergoing treatment for cancer. This theory proposes that avoidance is a maladaptive strategy of dealing with intrusive thoughts about a traumatic experience and suggests that avoidance mediates the relation between intrusive thoughts and later psychological distress. The role of disease-related factors, specifically changes in physical impairment and disease stage, was also examined.

METHODS

Patients (N = 189) undergoing treatment for cancer completed questionnaires at three time points, spaced 3 months apart. Intrusive thoughts, functional impairment, and psychological distress were assessed at Time 1, avoidance and functional impairment at Time 2, and psychological distress was assessed again at Time 3. The fit of the model was tested separately for patients with early-stage (stages 1 and 2) and late-stage (stages 3 and 4) disease.

RESULTS

The mediational role for avoidance was supported among patients with advanced stages of cancer but not for patients with early-stage disease. Results were inconsistent with predictions about the role of physical impairment. Among individuals with late-stage cancer, changes in functional impairment were not predictive of greater avoidance, and impairment had a significant but weak effect on the change in distress. Among patients with early-stage cancer, a deterioration in physical impairment was associated with increases in avoidance, and deterioration in physical impairment increased distress.

CONCLUSIONS

The results of this study were partially consistent with Creamer's cognitive processing theory. A moderating effect was found for disease stage on associations between intrusions, avoidance, physical impairment, and distress.

Measuring cancer patients' psychological distress and well-being: a factor analytic assessment of the Mental Health Inventory

This study examined the psychometric structure of the Mental Health Inventory (MHI) in 433 cancer patients. Using structural equation modeling, confirmatory factor analyses (CFAs) were conducted. Next, exploratory factor analysis (EFA) was used to explore an alternative MHI factor structure with a randomly chosen subsample. Finally, CFAs were conducted on 6 MHI models with the second subsample. Convergent validity was examined by administering the Positive and Negative Affect Schedule (PANAS) and the Dyadic Adjustment Scale (DAS). The CFAs with the original MHI factor structure indicated inadequate fit, supporting the need to conduct an EFA. Results of the EFA indicated support for a 5-factor solution but numerous differences in item factor loadings. The CFA indicated that the 5-factor correlated model was the best fitting model. Correlations between the PANAS and the DAS with the MHI provided preliminary support for the convergent validity of the MHI. Together, these results indicate that the original MHI factor structure may require modification for use in patients with cancer.

Association of psychological vulnerability factors to post-traumatic stress symptomatology in mothers of pediatric cancer survivors

The current study investigated whether individual differences in coping style, lifetime experience of traumatic events, perceived social support, and perceived social constraints were associated with symptoms of post-traumatic stress among 72 mothers of children who had successfully completed cancer treatment. Results suggested that more perceived social constraints and less perceived belonging support were associated with significantly more post-traumatic stress symptomatology, and this association was present after controlling for the effects of child age. Monitoring coping style and lifetime traumatic events were not significantly predictive of post-traumatic stress symptoms. The results of this study indicate that a sense of belonging to a social network as well as comfort expressing cancer-related thoughts and feelings to friends and family may play a key role in mothers' long-term adjustment to this extremely difficult life experience.

Perceived control, coping efficacy, and avoidance coping as mediators between spouses' unsupportive behaviors and cancer patients' psychological distress

This study examined whether avoidance, coping efficacy, and perceived control mediate the effects of spouses' unsupportive behaviors on patient psychological distress among 191 married individuals enrolled in cancer treatment. Results of the structural equation analyses suggested that avoidance and coping efficacy mediated the relationship between spouses' unsupportive behaviors and patient psychological distress. Perceived control of emotional aspects of the illness, including emotional responses and relationships with family and friends, and perceived control of the medical course of the cancer did not mediate the relationship between spouses' unsupportive behaviors and patient psychological distress. These findings suggest 2 mechanisms to explain why unsupportive responses from spouses may be associated with psychological distress among cancer patients.

Perceived control, coping efficacy, and avoidance coping as mediators between spouses' unsupportive behaviors and cancer patients' psychological distress

This study examined whether avoidance, coping efficacy, and perceived control mediate the effects of spouses' unsupportive behaviors on patient psychological distress among 191 married individuals enrolled in cancer treatment. Results of the structural equation analyses suggested that avoidance and coping efficacy mediated the relationship between spouses' unsupportive behaviors and patient psychological distress. Perceived control of emotional aspects of the illness, including emotional responses and relationships with family and friends, and perceived control of the medical course of the cancer did not mediate the relationship between spouses' unsupportive behaviors and patient psychological distress. These findings suggest 2 mechanisms to explain why unsupportive responses from spouses may be associated with psychological distress among cancer patients.

Description and demonstration of a CMOS amplifier-based-system with measurement and stimulation capability for bioelectrical signal transduction

An extracellular recording system incorporating an electrode array and an amplifier/stimulator CMOS chip is described and characterized. Important features of this custom VLSI chip include 16 instrumentation amplifiers with a gain of 50 and the incorporation of a cross-point array allowing designation of an extracellular microelectrode as either a stimulator or sensor. The planar array consisted of 32 microelectrodes, 14 microns in diameter, and four larger reference electrodes. Microelectrodes, interconnecting traces, and bond pads were patterned with a 500-nm layer of gold. The interconnecting traces were passivated with a 1-micron thick layer of silicon nitride to provide chemical and electrical insulation and microelectrode impedance was lowered utilizing electrode position of platinum black. The amplifier exhibited a nearly flat frequency response with high pass and low pass corner frequencies of 0.7 Hz and 50 kHz, respectively. The input referred noise over the 50 kHz bandwidth was 12-16 microVRMS, well below the magnitude of previously reported extracellular potentials. Crosstalk between neighboring channels resulted in an output signal below the amplifier noise level, even for relatively large extracellular potentials. Using this system, extracellular recording were demonstrated yielding typical peak-to-peak biopotentials of magnitude 0.9-2.1 mV and 100-400 microV for chick cardiac myocytes and rat spinal cord neurons, respectively. The key components of this extracellular recording system can be manufactured using industry standard thin film photolithographic techniques.

Brief report: acceptance of behavioral interventions for children with cancer: perceptions of parents, nurses, and community controls

OBJECTIVE

To examine the treatment acceptability of behavioral interventions targeting noncompliance in children with cancer, in medical versus general situations.

METHODS

Participants included 40 parents of children on active medical treatment for cancer, 42 pediatric oncology nurses, and 34 parents of medically healthy children. After reading a clinical vignette, participants rated the acceptability of five behavioral interventions via the Treatment Evaluation Inventory-Short Form.

RESULTS

Positive reinforcement, response cost, and reprimand generally were perceived as moderately acceptable. Overcorrection was perceived as unacceptable by all groups. Compared with nurses and parents of medically well children, parents of children with cancer provided significantly lower acceptability ratings for response cost and time-out, two of the punitive strategies studied.

CONCLUSIONS

Results suggest that clinicians should assess the acceptability of specific treatments prior to intervening. Methods for enhancing acceptability should be explored in future research.

Social support, social conflict, and adjustment among adolescents with cancer

OBJECTIVE

Evaluate support and conflict in close relationships of adolescents in active medical treatment for cancer. Family and friend perceptions of supportive and conflictual behaviors were examined in relation to psychological distress, taking into account the impact of functional impairment induced by the illness.

METHODS

Using self-report questionnaires, 50 adolescents between the ages of 12 and 20 years rated the frequency of supportive and conflictual interactions with parents, siblings and best friends.

RESULTS

Results indicated that perceived maternal conflict was associated with psychological distress. Conflict with fathers, siblings, and best friends was not associated with distress. Supportive aspects of close relationships did not predict psychological distress. The amount of physical impairment accounted for the most variance in distress, contributing between 35% and 38% of the variance.

CONCLUSION

Results suggest that mother-adolescent conflict would be an appropriate target for psychosocial interventions.

Biomimetic Pathways for Assembling Inorganic Thin Films

Living organisms construct various forms of laminated nanocomposites through directed nucleation and growth of inorganics at self-assembled organic templates at temperatures below 100°C and in aqueous solutions. Recent research has focused on the use of functionalized organic surfaces to form continuous thin films of single-phase ceramics. Continuous thin films of mesostructured silicates have also been formed on hydrophobic and hydrophilic surfaces through a two-step mechanism. First, under acidic conditions, surfactant micellar structures are self-assembled at the solid/liquid interface, and second, inorganic precursors condense to form an inorganic-organic nanocomposite. Epitaxial coordination of adsorbed surfactant tubules is observed on mica and graphite substrates, whereas a random arrangement is observed on amorphous silica. The ability to process ceramic-organic nanocomposite films by these methods provides new technological opportunities.

Inorganic Overgrowth of Aragonite on Molluscan Nacre Examined by Atomic Force Microscopy

The nacre (mother-of-pearl) that forms the irridescent inner layers of mollusc shells is a highly ordered microlaminate composite of aragonite crystals and biopolymers with a strength and fracture resistance that far exceed those of the mineral crystals themselves. The processes governing the biofabrication of this material by the secretory cells of the mantle are complex and only partially understood. We have used the atomic force microscope (AFM) to investigate the aqueous solution conditions under which mineral growth can occur on the nacreous layer of the shell of the bivalve mollusc Atrina sp. In situ imaging of the mature nacre surface exposed to a pH-controlled environment of natural seawater with added carbonate ions reveals that inorganic overgrowth of aragonite can occur within the ranges of pH and inorganic ion concentrations found in the molluscan extrapallial fluid from which the mineral is produced during biological shell growth. Thus, we posit that once nucleation has occurred, nacreous tablets could grow inorganically in the extrapallial space; the role of proteins and other macromolecules may be limited to initiating growth or controlling morphology through selective adsorption and spatial constraint on the growing crystal.

Colloidal gold particles as an incompressible atomic force microscope imaging standard for assessing the compressibility of biomolecules

Colloidal gold particles have multiple uses as three-dimensional atomic force microscopy imaging standards because they are incompressible, monodisperse, and spherical. The spherical nature of the particles can be exploited to characterize scanning tip geometry. As uniform spheres, colloidal gold particles may be used to calibrate the vertical dimensions of atomic force microscopy at the nanometer level. The monodisperse and incompressible nature of the gold can be used to characterize the vertical dimensions of coadsorbed biomolecules. Simultaneous measurements of gold with tobacco mosaic virus show that, at the same applied vertical force, the tobacco mosaic virus is undamaged by blunt tips but is compressed or disintegrated under sharper scanning styli, suggesting that specimen degradation is partly a pressure-dependent effect.

Humidity effects on atomic force microscopy of gold-labeled DNA on mica

Recent work in atomic force microscopy (AFM) of deoxyribonucleic acid (DNA) has relied on immobilizing DNA molecules by drying a small volume of buffered DNA solution onto cleaved mica. When imaging in air, relative humidity has been known to affect both the resolution and measured height of the DNA strands. We present data of measured height versus humidity for DNA and attached gold labels, and we propose a model for this data based on swelling of coadsorbed buffer salts upon exposure to moisture. In this model, small particles (e.g., DNA) stay near the top of the swelling salt layer, whereas larger particles (e.g., gold spheres) tend to be anchored down to the substrate until a moderate humidity is reached. At high humidity (around 65%), the salt layer becomes fluid-like and susceptible to tip-induced motion; the salts are either removed from the scan area or aggregate into island structures, depending on initial salt concentration on the surface.

Atomic Force Microscopy of Atomic-Scale Ledges and Etch Pits Formed During Dissolution of Quartz

The processes involved in the dissolution and growth of crystals are closely related. Atomic force microscopy (AFM) of faceted pits (called negative crystals) formed during quartz dissolution reveals subtle details of these underlying physical mechanisms for silicates. In imaging these surfaces, the AFM detected ledges <1 nanometer (nm) high that were spaced 10 to 90 nm apart. A dislocation pit, invisible to optical and scanning electron microscopy measurements and serving as a ledge source, was also imaged. These observations confirm the applicability of ledge-motion models to dissolution and growth of silicates; coupled with measurements of dissolution rate on facets, these methods provide a powerful tool for probing mineral surface kinetics.

Atomic-Resolution Electrochemistry with the Atomic Force Microscope: Copper Deposition on Gold

The atomic force microscope (AFM) was used to image an electrode surface at atomic resolution while the electrode was under potential control in a fluid electrolyte. A new level of subtlety was observed for each step of a complete electrochemical cycle that started with an Au(111) surface onto which bulk Cu was electrodeposited. The Cu was stripped down to an underpotential-deposited monolayer and finally returned to a bare Au(111) surface. The images revealed that the underpotential-deposited monolayer has different structures in different electrolytes. Specifically, for a perchloric acid electrolyte the Cu atoms are in a close-packed lattice with a spacing of 0.29 +/- 0.02 nanometer (nm). For a sulfate electrolyte they are in a more open lattice with a spacing of 0.49 +/- 0.02 nm. As the deposited Cu layer grew thicker, the Cu atoms converged to a (111)-oriented layer with a lattice spacing of 0.26 +/- 0.02 nm for both electrolytes. A terrace pattern was observed during dissolution of bulk Cu. Images were obtained of an atomically resolved Cu monolayer in one region and an atomically resolved Au substrate in another in which a 30 degrees rotation of the Cu monolayer lattice from the Au lattice is clearly visible.

Coping and adjustment to genital herpes: the effects of time and social support

The current study investigated the relationship of the passage of time and membership in a self-help group with coping behaviors and distress among people with genital herpes. A comparison between 116 people in herpes support groups and 36 community volunteers on the use of coping and level of emotional adjustment was undertaken. Results of the study indicated that people employed fewer coping strategies with increasing time since the onset of the stressor. This pattern was particularly clear in non-support-group subjects. In comparison, support-group members did not exhibit as significant a decrease in the use of coping strategies or as great an improvement in the level of depression and degree bothered by herpes over time. Selection factors and effects of self-help group membership are discussed as alternative explanations for these differences. Future research in the area of group membership as well as helpful and nonhelpful processes in these groups is suggested.

Coping and adjustment to genital herpes

The current study examined how individuals deal with genital herpes, a recurrent, incurable disease with a great psychological impact. An assessment battery composed of cognitive and problem-focused coping, attribution, and social support mechanisms was employed. These coping mechanisms were correlated with measures of psychological adjustment: self-esteem, depression, sexual adjustment, and amount upset by herpes. Subjects were 152 people with herpes recruited from self-help groups and people from the community who volunteered to participate in the study. Results supported several hypotheses derived from previous research on coping with life stressors. Cognitive coping mechanisms, especially negative thoughts, along with wishful thinking and characterological self-blame, were significant predictors of poor psychological adjustment. In addition, the repeated use of disease management strategies was found to correlate with poor psychological adjustment. Further research in the area of coping with chronic illness is suggested.

Bioequivalent chemical steam sterilization indicators

Biological indicators used to monitor steam sterilization cycles have two major shortcomings--the incubation period needed to determine if sterilization was accomplished, and the reliance on test packs for gathering information in each load. Chemical indicators do not suffer from these shortcomings. Chemical indicators can respond to time, temperature, and steam parameters to thus parallel the BI reaction. Nine commercially available chemical indicators and four biological indicators were evaluated under the conditions of dry heat, in a biological indicator-evaluator resistometer vessel, and in a hospital sterilizer. The results indicate that wider use of integrated chemical steam sterilization indicators is recommended.