Responsivity to Problem-Solving Skills Training in Mothers of Children With Cancer

OBJECTIVE

Bright IDEAS (BI) is a problem-solving skills training (PSST) program that has been demonstrated in earlier randomized controlled trials (RCTs) to be an effective and specific intervention for improving problem-solving skills and reducing negative affect in caregivers of children with cancer. The objectives of this study were to (a) offer an approach to defining meaningful treatment response and to determine the rates of responsivity to PSST; and (b) identify characteristics of PSST responders and nonresponders.

METHODS

Data from 154 mothers receiving the BI intervention were analyzed. Drawing on the literature on minimal clinically important differences, two criteria for determining responsivity were calculated for the primary outcome of problem-solving skills: (a) The reliable change index (RCI) based on group data, and; (b) The effect size (ES) of each participant's pre/postintervention change score as a function of the group's baseline SD.

RESULTS

Thirty-three percent of the sample met both responsivity criteria immediately posttreatment (39% at follow-up) and 38% (39% at follow-up) met neither. An additional 29% demonstrated a small or greater ES (≥ 0.2) but did not meet the RCI criteria, suggesting possible benefit. The single consistent predictor of responsivity was participants' pretreatment problem-solving skills, with lower skills at baseline predicting greater improvement (p < .001).

CONCLUSIONS

These findings highlight the need to go beyond group data in interpreting RCTs and to incorporate measures of meaningful treatment response. Our ability to predict and screen for meaningful treatment response is critical to more precise targeting, enhanced outcomes, and better resource allocation.

In-person vs. web-based administration of a problem-solving skills intervention for parents of children with cancer: Report of a randomized noninferiority trial

BACKGROUND

Bright IDEAS (BI) problem-solving skills training is an evidence-based intervention designed to help parents manage the demands of caring for a child with cancer. However, the resource intensiveness of this in-person intervention has limited its widespread delivery. We conducted a multicenter, randomized trial with a noninferiority design to evaluate whether a web-based version of BI requiring fewer resources is noninferior to in-person administration.

METHODS

621 caregivers of children with newly diagnosed cancer were randomly assigned to standard BI delivered face-to-face or a web-based version delivered via mobile device. The primary outcome was caregiver-reported problem-solving skills. The noninferiority margin was defined as 0.2 standard deviation units of the change from baseline to end of intervention. Secondary outcomes included caregiver-reported mood disturbance, depression, and posttraumatic stress symptoms. The study was registered with ClinicalTrials.gov Identifier: NCT01711944.

FINDINGS

The effect of the standard treatment was preserved; parents in the standard BI arm improved their problem-solving (effect size = 0.53, t = 8.88, p < .001). Parents in the web-based BI group also improved their problem-solving (effect size = 0.32, t = 5.32, p < .001). Although the web-based intervention preserved 60% of the standard treatment effect, the test of noninferiority was non-significant (effect size = -0.21, p = 0.55). Similarly, the web-based intervention preserved > 60% of the standard intervention effect on all secondary outcomes; however, tests of noninferiority were non-significant.

INTERPRETATION

Noninferiority of web-based BI relative to standard face-to-face administration was not established. Further development of the web-based BI is needed before it can be recommended as a stand-alone intervention. However, the documented benefits of the web-based intervention as well as the advantages of low resource utilization and ease of delivery suggest that further development of web-based BI is indicated, and that it may play a valuable role in alleviating distress in caregivers of children with serious or chronic illness.

FUNDING

National Institutes of Health (U.S.), R01 CA159013 (P.I. Sahler).

Measuring Medication Adherence in Pediatric Cancer: An Approach to Validation

Objective

This study described the prospective relationship between pharmacological and behavioral measures of 6-mercaptopurine (6MP) medication adherence in a multisite cohort of pediatric patients diagnosed with cancer ( N  = 139).

Methods

Pharmacological measures (i.e., metabolite concentrations) assessed 6MP intake. Behavioral measures (e.g., electronic monitoring) described adherence patterns over time.

Results

Three metabolite profiles were identified across 15 months: one group demonstrated low levels of both metabolites (40.8%) consistent with nonadherence and/or suboptimal therapy; two other groups demonstrated metabolite clusters indicative of adequate adherence (59.2%). Those patients whose metabolite profile demonstrated low levels of both metabolites had consistently lower behavioral adherence rates.

Conclusions

To our knowledge, this was the first study to prospectively validate a pharmacological measure of medication adherence with a behavioral adherence measure in a relatively large sample of pediatric patients with cancer. Using multiple methods of adherence measurement could inform clinical care and target patients in need of intervention.

Electronic monitoring of medication adherence in early maintenance phase treatment for pediatric leukemia and lymphoma: identifying patterns of nonadherence

OBJECTIVE

To describe patterns of treatment adherence to early maintenance phase therapy for acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL).

METHODS

Using an objective observational method (electronic monitoring), adherence was examined for 139 patients aged 7-19 years diagnosed with ALL or LBL across 6 centers.

RESULTS

The mean adherence percentage was 86.2%. Adherence rates declined over the 1-month of follow-up to 83%. 3 linear trajectories of 6-mercaptopurine adherence were identified: (1) exemplary adherence (n = 99): Averaging nearly 100%; (2) deteriorating (n = 23): Adherence decreased from 100 to 60%; and (3) chronically poor adherence (n = 9): Averaging 40%.

CONCLUSIONS

Adherence promotion interventions might be tailored to subgroups of patients who demonstrated problematic patterns of treatment adherence that could place them at risk for relapse. This research demonstrates the importance of using objective real-time measures of medication adherence for measuring and documenting adherence patterns.

Benefit finding in fathers of childhood cancer survivors: a retrospective pilot study

There is a growing literature examining positive outcomes following traumatic experiences. Although the diagnosis of a child with cancer poses extraordinary challenges for the family, awareness is growing that such a life-changing event can be a catalyst for positive growth. The current mixed methods study investigated benefit finding in fathers (N = 25) of childhood cancer survivors. Benefit finding included positive changes resulting from adversity. Participants completed a benefit finding measure and an interview describing their experience and benefits from the challenges faced during their child's cancer journey. Findings indicated that fathers endorsed high levels of benefit finding (mean = 4.1 out of 5) specifically in personal growth, spiritual change, and relationships with others. Our study extends the literature by examining how their child's cancer journey contributed to specific domains of paternal benefit finding. These results support the use of a positive psychology framework for understanding effects of a child's cancer diagnosis on caregivers.

Intellectual functioning and multi-dimensional attentional processes in long-term survivors of a central nervous system related pediatric malignancy

AIMS

Central nervous system (CNS) malignancies and/or their treatment in pediatric cancer survivors are known to be associated with deficits in neuropsychological functions. We report findings from a nation-wide study of childhood cancer survivors to investigate intelligence and attention/concentration from a multi-dimensional perspective in a diverse sample from this population.

MAIN METHODS

Four hundred forty-four pediatric cancer survivors between 6 and 17 years of age, who had suffered CNS involvement associated with their malignancy, were evaluated. All patients completed a measure of general intelligence. Attention was measured by a continuous performance test (CPT) and by parental report using a standardized psychological inventory.

KEY FINDINGS

Social economic status (SES) was a significant predictor of intellectual functioning and scores on independent measures of attention. After controlling for SES, cranial radiation therapy (CRT) was strongly predictive of impairments in intellectual functioning. Patients who had completed a transplant procedure did not have significant impairments in intellectual functioning when compared to other participants. CPT performance was most clearly influenced by a younger age at diagnosis and the presence of a supratentorial brain tumor. Reaction time was lower in patients who had received CRT. Gender did not correlate with CPT performance, but caregiver reports of deficits in attentional functioning were more prevalent in girls compared to boys.

SIGNIFICANCE

These findings are important given the large, representative sample and multi-dimensional assessment of attentional functioning. The presence of a very strong SES effect on all dependent variables must be addressed in studies of this nature.

Evaluation of the psychometric properties of the Pediatric Parenting Stress Inventory (PPSI)

OBJECTIVE

This work evaluated the psychometric properties of the Pediatric Parenting Stress Inventory (PPSI), a new measure of problems and distress experienced by parents of children with chronic illnesses.

METHOD

This secondary data analysis used baseline data from 1 sample of English-, Spanish-, and Hebrew-speaking mothers of children recently diagnosed with cancer (n = 449) and 1 sample of English- and Spanish-speaking mothers of children recently diagnosed with cancer (n = 399) who participated in 2 problem-solving skills training interventions. The PPSI was administered at baseline with other measures of maternal distress. Factor structure was evaluated using exploratory factor analysis (EFA) on the first sample and confirmatory factor analysis (CFA) on both samples. Internal consistency was evaluated using Cronbach's alpha. Construct validity was assessed via Spearman correlations with measures of maternal distress.

RESULTS

EFA resulted in a stable four-factor solution with 35 items. CFA indicated that the four-factor solution demonstrated reasonable fit in both samples. Internal consistency of the subscales and full scale was adequate to excellent. Construct validity was supported by moderate to strong correlations with measures of maternal distress, depression, and posttraumatic stress symptoms.

CONCLUSIONS

The PPSI demonstrated good psychometric properties in assessing current problems and distress experienced by mothers of children newly diagnosed with cancer. This tool may be used to identify individualized targets for intervention in families of children with cancer. Future studies could evaluate the utility and psychometrics of the PPSI with other pediatric populations.

Specificity of problem-solving skills training in mothers of children newly diagnosed with cancer: results of a multisite randomized clinical trial

PURPOSE

Diagnosis of cancer in a child can be extremely stressful for parents. Bright IDEAS, a problem-solving skills training (PSST) intervention, has been shown to decrease negative affectivity (anxiety, depression, post-traumatic stress symptoms) in mothers of newly diagnosed patients. This study was designed to determine the specificity of PSST by examining its direct and indirect (eg, social support) effects compared with a nondirective support (NDS) intervention.

PATIENTS AND METHODS

This randomized clinical trial included 309 English- or Spanish-speaking mothers of children diagnosed 2 to 16 weeks before recruitment. Participants completed assessments prerandomization (T1), immediately postintervention (T2), and at 3-month follow-up (T3). Both PSST and NDS consisted of eight weekly 1-hour individual sessions. Outcomes included measures of problem-solving skill and negative affectivity.

RESULTS

There were no significant between-group differences at baseline (T1). Except for level of problem-solving skill, which was directly taught in the PSST arm, outcome measures improved equally in both groups immediately postintervention (T2). However, at the 3-month follow-up (T3), mothers in the PSST group continued to show significant improvements in mood, anxiety, and post-traumatic stress; mothers in the NDS group showed no further significant gains.

CONCLUSION

PSST is an effective and specific intervention whose beneficial effects continue to grow after the intervention ends. In contrast, NDS is an effective intervention while it is being administered, but its benefits plateau when active support is removed. Therefore, teaching coping skills at diagnosis has the potential to facilitate family resilience over the entire course of treatment.

Regulation of mRNA expression encoding chaperone and co-chaperone proteins of the glucocorticoid receptor in peripheral blood: association with depressive symptoms during pregnancy

BACKGROUND

Major depressive disorder during pregnancy associates with potentially detrimental consequences for mother and child. The current study examined peripheral blood gene expression as a potential biomarker for prenatal depressive symptoms.

METHOD

Maternal RNA from whole blood, plasma and the Beck Depression Inventory were collected longitudinally from preconception through the third trimester of pregnancy in 106 women with a lifetime history of mood or anxiety disorders. The expression of 16 genes in whole blood involved in glucorticoid receptor (GR) signaling was assessed using real-time polymerase chain reaction. In parallel, plasma concentrations of progesterone, estradiol and cortisol were measured. Finally, we assessed ex vivo GR sensitivity in peripheral blood cells from a subset of 29 women.

RESULTS

mRNA expression of a number of GR-complex regulating genes was up-regulated over pregnancy. Women with depressive symptoms showed significantly smaller increases in mRNA expression of four of these genes - FKBP5, BAG1, NCOA1 and PPID. Ex vivo stimulation assays showed that GR sensitivity diminished with progression of pregnancy and increasing maternal depressive symptoms. Plasma concentrations of gonadal steroids and cortisol did not differ over pregnancy between women with and without clinically relevant depressive symptoms.

CONCLUSIONS

The presence of prenatal depressive symptoms appears to be associated with altered regulation of GR sensitivity. Peripheral expression of GR co-chaperone genes may serve as a biomarker for risk of developing depressive symptoms during pregnancy. The presence of such biomarkers, if confirmed, could be utilized in treatment planning for women with a psychiatric history.

Quantifying the relationship among hospital design, satisfaction, and psychosocial functioning in a pediatric hematology-oncology inpatient unit

BACKGROUND

Studies show that hospital built environments can affect physical and psychological outcomes and healthcare satisfaction in adults, but pediatric research is sparse.

OBJECTIVE

To investigate the effects of the built environment on hospitalized pediatric hematology-oncology patients and their parents by testing the hypothesis that perceived built environment satisfaction mediates the relationship between the objective built environment and psychosocial functioning, as well as parental healthcare satisfaction.

METHODS

The hospital built environment was evaluated subjectively through the PedsQL™ Hospital Healing Environment Module satisfaction questionnaires and objectively by quantifying environmental features. Outcomes for patients and parents included present functioning and affect. Healthcare satisfaction was also assessed for parents. Structural equation modeling (SEM) was used to test the mediational hypothesis.

SUBJECTS

Participants were 90 hospitalized pediatric hematology-oncology patients and 149 parents of pediatric hematology-oncology patients.

RESULTS

For both parents and children, analyses revealed a significant positive relationship between the quality of the objective built environment and built environment satisfaction. For parents, significant relationships emerged in the expected direction between built environment satisfaction and present functioning, healthcare satisfaction, and negative affect.

CONCLUSIONS

Both pediatric hematology-oncology patients and their parents can reliably report their own perceived built environment satisfaction, which is significantly related to the quality of the objective built environment. For parents, results support the mediational hypothesis, highlighting the importance that perceived built environment satisfaction plays in psychosocial functioning and healthcare satisfaction.

Qualitative analysis of the role of culture in coping themes of Latina and European American mothers of children with cancer

It has been well established that mothers of children diagnosed with cancer experience high levels of distress. Latina mothers may be at risk for higher levels of distress related to language barriers, cultural factors, and economic, immigration, and acculturation stressors. Despite the increasing US Latino population, few studies have examined the role of culture within pediatric oncology, including how mothers cope with their child's cancer. This study used qualitative analysis of 24 sessions from 3 Latina and 3 European American mothers of children recently diagnosed with cancer. The session transcripts were divided into a total of 2328 thought segments that were then analyzed for themes using a collaborative iterative process. Analysis identified 9 shared coping themes that included, with some variations: gathering information, professional help-seeking, activities, problem solving, positive thinking, present orientation, reframing, avoidance, and religion. Three themes were culture specific: only European American mothers discussed compromise, whereas normalization and perspective taking were unique to the Latina mothers and suggest that the cultural value of simpatía influences coping. Clinical and research recommendations are discussed.

Interventions to improve neuropsychological functioning in childhood cancer survivors

A very brief historical review on the identification of neurocognitive deficits in patients treated for a pediatric malignancy that involved CNS disease, treatment, or a combination is provided. This review is particularly directed toward providing a foundation upon which the introduction of specific brain injury rehabilitation efforts and subsequent research were introduced into this population of patients. Three primary methods by which clinicians and researchers have attempted to improve neurocognitive functioning with survivors of pediatric cancer that have suffered a CNS insult are identified. From a pharmacological perspective, research is reviewed that documents the potential beneficial effects of stimulant medication. Results of two drug trials that used double-blind crossover methodology are reviewed, and it is highly likely that medications may be of significant benefit to pediatric cancer survivors who are experiencing attentional deficits, impairment in social functioning, and also declines in academic achievement. We next describe psychologically based brain injury rehabilitation efforts, including on-treatment schooling and reentry, within the survivor population. A phase III clinical trial of a comprehensive rehabilitation approach is discussed in detail. New directions in the area of brain injury rehabilitation for childhood cancer survivors are presented, and the need for professionals in this area to work toward a team approach is emphasized.

Problem solving and maternal distress at the time of a child's diagnosis of cancer in two-parent versus lone-parent households

OBJECTIVE

To examine negative affectivity and problem-solving abilities for lone mothers and those who are married/partnered subsequent to a child's diagnosis with cancer.

METHODS

Negative affectivity and problem-solving strategies were assessed for 464 mothers (87 lone and 377 married/partnered) within 2-16 weeks of their child's diagnosis with cancer.

RESULTS

The two groups of mothers did not differ significantly on measures of perceived posttraumatic stress or problem-solving; lone mothers reported significantly more symptoms of depression. This difference was no longer significant when maternal education was taken into account.

CONCLUSIONS

Negative affectivity and problem-solving abilities were similar for lone mothers and those that are married/partnered shortly after their child has been diagnosed with cancer. Findings are discussed within the context of contemporary strategies to assess marital status as proxy variable for various underlying constructs.

Report from a multi-institutional randomized clinical trial examining computer-assisted problem-solving skills training for English- and Spanish-speaking mothers of children with newly diagnosed cancer

OBJECTIVES

To evaluate the feasibility and efficacy of a handheld personal digital assistant (PDA)-based supplement for maternal Problem-Solving Skills Training (PSST) and to explore Spanish-speaking mothers' experiences with it.

METHODS

Mothers (n = 197) of children with newly diagnosed cancer were randomized to traditional PSST or PSST + PDA 8-week programs. Participants completed the Social Problem-Solving Inventory-Revised, Beck Depression Inventory-II, Profile of Mood States, and Impact of Event Scale-Revised pre-, post-treatment, and 3 months after completion of the intervention. Mothers also rated optimism, logic, and confidence in the intervention and technology.

RESULTS

Both groups demonstrated significant positive change over time on all psychosocial measures. No between-group differences emerged. Despite technological "glitches," mothers expressed moderately high optimism, appreciation for logic, and confidence in both interventions and rated the PDA-based program favorably. Technology appealed to all Spanish-speaking mothers, with younger mothers showing greater proficiency.

CONCLUSIONS

Well-designed, supported technology holds promise for enhancing psychological interventions.

A multicenter, randomized clinical trial of a cognitive remediation program for childhood survivors of a pediatric malignancy

Survivors of childhood cancer whose malignancy and/or treatment involved the central nervous system may demonstrate a consistent pattern of neurocognitive deficits. The present study evaluated a randomized clinical trial of the Cognitive Remediation Program (CRP). Participants were 6- to 17-year-old survivors of childhood cancer (N = 161; 35% female, 18% Hispanic, 10% African American, 64% Caucasian, 8% other) who were at least 1 year off treatment and who manifested an attentional deficit. They were enrolled at 7 sites nationwide. Two thirds of the participants were randomly assigned to cognitive remediation. All participants were assessed using a battery of academic achievement/neurocognitive tests and parent/teacher measures of attention. The CRP resulted in parent report of improved attention and statistically significant increases in academic achievement. Effect sizes were modest but were comparable with those for other clinical trials of brain injury rehabilitation and for psychological interventions in general. The CRP is presented as a potentially beneficial treatment for many survivors of pediatric cancer. Long-term clinical significance remains unproven. Further work is needed to improve effect sizes and treatment compliance and to address the needs of other populations with pediatric brain injury.

Attention dysfunction and parent reporting in children with brain tumors

BACKGROUND

The IQ declines observed in children treated for brain tumor emerge as "late effects" and are conceptualized as secondary to changes in underlying mental processes, such as attention. Early identification of the underlying changes might help minimize the long-term adverse outcomes. We evaluated the validity of a time-efficient, standardized parent-report measure in identifying attention dysfunction in childhood brain tumor survivors.

PROCEDURE

Seventy survivors between ages 6 and 16 who met eligibility criteria and who had completed a standard neuropsychological evaluation were classified into an attention dysfunction group and a non-attention dysfunction group, based on their performance on objective measures of attention. Analysis of covariance was used to evaluate group differences on the widely used, parent report Child Behavioral Checklist (CBCL).

RESULTS

Survivors in the attention dysfunction group were reported by their parents as having significantly more attention problems relative to the group without attention dysfunction on objective testing. Furthermore, survivors categorized as having attention dysfunction based on their neuropsychological test scores were reported on the CBCL by their parents as having significantly more social problems compared to the non-attention dysfunction group.

CONCLUSIONS

Standardized parent reporting of attention problems shows promise as a screening tool to detect attention dysfunction among survivors of childhood brain tumors. Findings include a strong association of decreased social functioning with attention dysfunction in brain tumor survivors. Furthermore, exploratory data suggest that the behavioral presentation of attention dysfunction in this group may be different from other clinical groups.

The PedsQL Brain Tumor Module: initial reliability and validity

BACKGROUND

Brain tumors (BT) are second only to acute lymphoblastic leukemia as the most prevalent form of pediatric cancer, with BT 5-year survival rates approaching 70%. With increased survival, quality of life has emerged as an essential health outcome. This investigation examines the internal consistency reliability and construct validity of the Pediatric Quality of Life Inventory (PedsQL) Brain Tumor Module.

METHODS

The PedsQL 4.0 Generic Core Scales, PedsQL Multidimensional Fatigue Scale, and PedsQL Brain Tumor Module were administered to 99 families. The average age of the 56 boys and 43 girls was 9.76 years (range=2-18 years). The sample included children with tumors located in the posterior fossa/brainstem (N=62, 62.6%), supratentorial (N=15, 15.2%), and midline (N=22, 22.2%). Children were on treatment (N=46, 46.5%), off treatment<12 months (N=19, 19.2%), or off treatment>12 months/long-term survivor (N=34, 34.3%). Treatment included radiation (N=61, 61.6%), surgery (N=83, 83.8%), chemotherapy (N=87, 87.9%), and bone marrow transplant (N=5, 5.1%).

RESULTS

Internal consistency reliability was demonstrated for the 24-item PedsQL Brain Tumor Module (average alpha=0.78-0.92, parent proxy-report, n=99; average alpha=0.76-0.87, child self-report, n=51). Construct validity for the PedsQL Brain Tumor Module was supported through an analysis of the intercorrelations with the Generic Core Scales and Fatigue Scale.

CONCLUSIONS

The findings provide support for the measurement properties of the PedsQL Brain Tumor Module.

Trajectories of Adjustment in Mothers of Children with Newly Diagnosed Cancer: A Natural History Investigation

OBJECTIVES

The objectives of this study were (a) to assess negative affectivity and posttraumatic symptomatology in mothers following the diagnosis of cancer in their children; (b) to examine sociodemographic and psychosocial variables associated with change in distress over time; and (c) to identify distinct subgroups of mothers whose patterns and trajectories of adjustment can be distinguished according to available predictor data.

METHODS

Two hundred and twelve mothers at seven sites were assessed just following their child's diagnosis, and again 3 months and 6 months later. Primary outcomes included measures of mood disturbance, depressive symptoms, and symptoms of posttraumatic stress.

RESULTS

Overall, mothers demonstrated a pattern of mildly elevated negative affectivity and posttraumatic symptomatology initially, with steady improvements evident at 3- and 6-month follow-up. Distinct adjustment trajectories were evident within the sample as a whole, indicating subgroups of mothers with high-declining, moderate-stable, and low-stable distress levels.

CONCLUSIONS

These findings highlight considerable resilience among mothers facing the stress of childhood cancer. Intervention efforts aimed at reducing maternal distress might best be targeted towards the subgroup of mothers who may be predicted to exhibit the highest level of distress.

Using problem-solving skills training to reduce negative affectivity in mothers of children with newly diagnosed cancer: report of a multisite randomized trial

Mothers of children with cancer experience significant distress associated with their children's diagnosis and treatment. The efficacy of problem-solving skills training (PSST), a cognitive-behavioral intervention based on problem-solving therapy, was assessed among 430 English- and Spanish-speaking mothers of recently diagnosed patients. Participants were randomized to usual psychosocial care (UPC; n=213) or UPC plus 8 sessions of PSST (PSST; n=217). Compared with UPC mothers, PSST mothers reported significantly enhanced problem-solving skills and significantly decreased negative affectivity. Although effects were largest immediately after PSST, several differences in problem-solving skills and distress levels persisted to the 3-month follow-up. In general, efficacy for Spanish-speaking mothers exceeded that for English-speaking mothers. Findings also suggest young, single mothers profit most from PSST.

Parent proxy-reported health-related quality of life and fatigue in pediatric patients diagnosed with brain tumors and acute lymphoblastic leukemia

BACKGROUND

Pediatric patients with brain tumors (BT) are often excluded from health-related quality of life (HRQOL) studies even though they experience more severe disease and treatment-related sequelae than children with other types of cancer. Parent proxy assessments of HRQOL allow for greater inclusion of children who are developmentally immature, physically ill, or cognitively impaired.

METHODS

Parents of children ages 2-18 years who were diagnosed at Childrens Hospital Los Angeles and Children's Hospital San Diego with BT (n = 86) or acute lymphoblastic leukemia (ALL; n = 170) evaluated their children's HRQOL over the previous week using the parent-proxy versions of the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core scales, the PedsQL 3.0 Acute Cancer Module, and the PedsQL Multidimensional Fatigue scales. Multiple regression analyses were used to determine the independent effect of the child's diagnosis on HRQOL. Separate analyses were conducted for patients receiving treatment, patients who had not received treatment for < 12 months, and patients who had not received treatment for > or = 12 months.

RESULTS

Patients with BT exhibited more problems than patients with ALL in the physical, social, psychosocial, school, cognitive, and fatigue domains of HRQOL. The Core Physical Health, Core Psychosocial Health, and Fatigue Total scores for patients with BT demonstrated peak improvements for children who had not received treatment for < 12 months and sharp declines for children who had not received treatment for > or = 12 months. The Core Physical Health and Fatigue Total scores for patients with ALL were highest (better HRQOL) for those who had not received treatment for > or = 12 months.

CONCLUSIONS

Pediatric patients and survivors of BT experienced more fatigue and HRQOL problems than patients with ALL, and HRQOL differed by treatment status.

The PedsQL in pediatric cancer pain: a prospective longitudinal analysis of pain and emotional distress

The objective of this prospective study was to investigate the cross-sectional and longitudinal associations between pain and emotional distress in children and adolescents with cancer as measured by the Pediatric Quality of Life Inventory (PedsQL) Emotional Functioning and Pain Scales. The PedsQL 1.0 Generic Core Scales are multidimensional scales developed as the generic core measure to be integrated with the PedsQL Disease-Specific Modules. The PedsQL 1.0 Cancer Module was designed to measure pediatric cancer-specific health-related quality of life. The PedsQL Generic Core Scales, Emotional Functioning Scale and Cancer Module Pain Scale, were administered to 69 children and 59 adolescents and their parents at Time 1 and Time 2, which was 6 months on average after Time 1. Prospective hierarchical multiple regression analyses supported a longitudinal predictive model with Time 1 pain predicting Time 2 pain and Time 1 emotional distress predicting Time 2 emotional distress, respectively. Time 1 emotional distress did not predict Time 2 pain, and Time 1 pain did not predict Time 2 emotional distress. The results demonstrate that pediatric cancer pain and emotional distress, although associated cross-sectionally, are differentially predictive in prospective longitudinal analyses. These results suggest that both pain and emotional distress should be targeted for treatment interventions concurrently to enhance long-term health-related quality of life of the pediatric patient with cancer.

Problem-solving skills training for mothers of children with newly diagnosed cancer: a randomized trial

Mothers of children with serious illnesses have lower levels of well-being than mothers in the general population. Problem-solving therapy (PST), a cognitive-behavioral intervention, has been shown to be effective in treating negative affectivity (depression, anxiety) and other manifestations of reduced well-being. This report describes a problem-solving skills training (PSST) intervention, based on problem-solving therapy, for mothers of newly diagnosed pediatric cancer patients. Ninety-two mothers were randomly assigned to receive PSST or to receive standard psychosocial care (Control Group). After the 8-week intervention, mothers in the PSST Group had significantly enhanced problem-solving skills and significantly decreased negative affectivity compared with controls. Analysis revealed that changes in self-reports of problem-solving behaviors accounted for 40% of the difference in mood scores between the two groups. Interestingly, PSST had the greatest impact on improving constructive problem solving, whereas improvement in mood was most influenced by decreases in dysfunctional problem solving. The implications of these findings for refinement of the PSST intervention and for extension to other groups of children with serious illnesses are discussed.

The PedsQL in pediatric cancer: reliability and validity of the Pediatric Quality of Life Inventory Generic Core Scales, Multidimensional Fatigue Scale, and Cancer Module

BACKGROUND

The Pediatric Quality of Life Inventory (PedsQL) is a modular instrument designed to measure health-related quality of life (HRQOL) in children and adolescents ages 2-18 years. The PedsQL 4.0 Generic Core Scales are multidimensional child self-report and parent proxy-report scales developed as the generic core measure to be integrated with the PedsQL disease specific modules. The PedsQL Multidimensional Fatigue Scale was designed to measure fatigue in pediatric patients. The PedsQL 3.0 Cancer Module was designed to measure pediatric cancer specific HRQOL.

METHODS

The PedsQL Generic Core Scales, Multidimensional Fatigue Scale, and Cancer Module were administered to 339 families (220 child self-reports; 337 parent proxy-reports).

RESULTS

Internal consistency reliability for the PedsQL Generic Core Total Scale Score (alpha = 0.88 child, 0.93 parent report), Multidimensional Fatigue Total Scale Score (alpha = 0.89 child, 0.92 parent report) and most Cancer Module Scales (average alpha = 0.72 child, 0.87 parent report) demonstrated reliability acceptable for group comparisons. Validity was demonstrated using the known-groups method. The PedsQL distinguished between healthy children and children with cancer as a group, and among children on-treatment versus off-treatment. The validity of the PedsQL Multidimensional Fatigue Scale was further demonstrated through hypothesized intercorrelations with dimensions of generic and cancer specific HRQOL.

CONCLUSIONS

The results demonstrate the reliability and validity of the PedsQL Generic Core Scales, Multidimensional Fatigue Scale, and Cancer Module in pediatric cancer. The PedsQL may be utilized as an outcome measure in clinical trials, research, and clinical practice.

Altered prestarvation response in a nystatin resistant Dictyostelium discoideum mutant

Wild-type Dictyostelium amoebae secrete an autocrine, prestarvation factor (PSF) that allows them to measure the amount of food bacteria compared to their cell density. When the ratio of PSF to bacteria reaches a threshold, the cells are signaled to prepare for eventual starvation. This prestarvation response (PSR) usually starts three to four generations before the end of exponential growth, leading to the accumulation of several aggregation specific genes during growth. We characterize a nystatin-resistant mutant, HK19, that expresses the PSR genes three generations earlier than wild type but has an otherwise wild-type PSR. Although HK19 has a full PSR during growth, HK19 continues to grow at the wild-type rate and reaches normal cell densities. Because HK19 temporally separates the PSR from starvation, it became possible to test whether starvation is required for development. Since HK19 growing at low density can be induced to clump with either cAMP or folate, it appears that the PSR and an external signal are sufficient for entry into development. These data suggest that the PSR is a complex genetic pathway that induces genes involved in the exit from growth and the entry into development.

Mediation of cell-substratum adhesion by RasG in Dictyostelium

Previous studies on the functions of the RasG gene in the cellular slime mold, Dictyostelium discoideum, have revealed that it is required for normal motility and cytokinesis. To further understand how the RasG gene regulates various cellular processes, we transformed an activated form of RasG, that is, RasG (G12T), a mutation from glycine to threonine at amino acid position 12 into wild type KAX-3 cells. This produced moderate but constitutive RasG(G12T) protein expression, which causes cells to become significantly more adherent to the substratum than are wild type cells. The RasG(G12T) transformants also grow slowly on bacterial plates, and engulf fewer bacteria on filter surfaces, indicating a defect in phagocytosis when cells are adhered. The expression of the activated RasG also dramatically reduces the number of filopodia on the cell surface. Tyrosine phosphorylation on a 43 kDa protein (most likely actin) of the RasG (G12T) transformants is highly elevated. Taken together, our observations suggest that RasG is crucial for Dictyostelium cell-substratum adhesion during growth and that RasG may play a role in adhesion-mediated phagocytosis. Our results also suggest that RasG is important in filopodial formation and that RasG is involved in the signal pathway that is regulated by tyrosine phosphorylation.

Children's memories for painful cancer treatment procedures: implications for distress

Children (ages 3 to 18, N = 55) diagnosed with leukemia were tested for their memories of lumbar punctures (LPs), a repeated and painful part of the cancer treatment protocol. Memory for both event details and the child's emotional responses was assessed one week after the LP. Children of all ages displayed considerable accuracy for event details, and accuracy increased with age. Overall recall accuracy for event details and emotional responses was similar. Recall among children given oral Versed was similar to that among children not given Versed. Finally, higher distress predicted greater exaggerations in negative memory 1 week later (although controlling for age weakened this relationship); moreover, greater exaggerations in negative memory predicted higher distress at a subsequent LP. These results indicate that children's memories play an important role in their experience of distress during repeated stressful events.

The Pediatric Cancer Quality of Life Inventory: a modular approach to measuring health-related quality of life in children with cancer

Measurement of pediatric cancer patients' health-related quality of life (HRQL) in phase III randomized, controlled clinical trials is being recognized increasingly as an essential component in evaluating the comprehensive health outcomes of modern anti-neoplastic treatment protocols. Use of a brief core measure of HRQL plus disease-specific symptom modules is a way to assess specific HRQL outcomes with a minimum of subject burden. Demonstrating a measure's feasibility, reliability and validity also represents children's ability to provide reliable and valid responses to HRQL questions. The Pediatric Cancer Quality of Life Inventory (PCQL) Modular Approach consists of a 15-item core measure of HRQL and 2 specific symptom modules: pain and nausea. To validate a patient-report form and a parent-report form, the PCQL was administered to 291 pediatric cancer patients and to their parents. Feasibility and range of measurement, as well as patient-parent concordance, were assessed. Internal consistency reliability was assessed via Cronbach's alpha. Validity was determined by the known-groups approach and by correlating PCQL scores with days missed from school. Patients had minimal missing data, and the range of measurement for the items was good. Patient-parent concordance was large but not perfect. For both patient and parent forms, internal consistency reliability of the PCQL core scale (0.83 and 0. 86, respectively) was strong. The internal consistency reliabilities of the 2 symptom modules for both patient and parent forms were in the acceptable range for group comparisons. Regarding clinical validity, the core scale and the 2 symptom modules distinguished between patients on and off treatment for both patient and parent reports. Further, both patient and parent reports correlated with days of missed school in the past 6 and 12 months. The PCQL Modular Approach has demonstrated acceptable internal consistency reliability and clinical validity for both patient-report and parent-report forms. By implication, children are capable of providing reliable and valid responses to these HRQL questions.

Pain-sensitive temperament: does it predict procedural distress and response to psychological treatment among children with cancer?

OBJECTIVE

To evaluate the relationship between pain sensitivity and children's distress during lumbar punctures (LPs), and whether pain sensitivity functions as a moderator of children's responses to a psychological intervention aimed at reducing LP distress.

METHOD

Fifty-five children with acute lymphoblastic leukemia (ages 3 to 18) and their parents completed a questionnaire measure of pain sensitivity. Self-report, physiological, and observed measures of distress were collected during the study baseline LP. Children were then randomized into a psychological intervention or an attention control group. Postintervention and follow-up LPs were observed.

RESULTS

Higher levels of pain sensitivity were associated with greater anxiety and pain, both prior to and during the LP. Preliminary analyses indicated that pain sensitivity moderated the effects of intervention on distress. Children who were more pain-sensitive and who received no intervention showed greater increases in LP distress over time. In contrast, children who were more pain-sensitive and who received intervention showed greater decreases in LP distress over time.

CONCLUSIONS

A measurement of pain sensitivity may be useful in pediatric oncology settings for effectively targeting pain-vulnerable children for psychological intervention. Preliminary analyses indicate that an empirically-supported intervention for procedural distress is efficacious for those children who are most pain-sensitive.

Alteration of memory in the reduction of children's distress during repeated aversive medical procedures

The present study sought to reduce children's distress during aversive medical procedures using a brief, cost-effective intervention aimed at reframing memory. Fifty children diagnosed with leukemia (25 treatment, 25 attention control, aged 3-18) were observed as they underwent 3 consecutive lumbar punctures (LPs; baseline, postintervention, and follow-up). Self-report, physiological, and observable distress measures were collected before and after each LP. At posttreatment, children in the intervention group showed reductions in anticipatory physiological and self-report ratings relative to the control group. At follow-up, these effects generalized to reductions in procedural distress. These results suggest that (a) a simple memory-based intervention is efficacious at reducing children's distress and (b) benefits from this intervention are maintained over 1 week even without continued intervention.

Alteration of memory in the reduction of children's distress during repeated aversive medical procedures

The present study sought to reduce children's distress during aversive medical procedures using a brief, cost-effective intervention aimed at reframing memory. Fifty children diagnosed with leukemia (25 treatment, 25 attention control, aged 3-18) were observed as they underwent 3 consecutive lumbar punctures (LPs; baseline, postintervention, and follow-up). Self-report, physiological, and observable distress measures were collected before and after each LP. At posttreatment, children in the intervention group showed reductions in anticipatory physiological and self-report ratings relative to the control group. At follow-up, these effects generalized to reductions in procedural distress. These results suggest that (a) a simple memory-based intervention is efficacious at reducing children's distress and (b) benefits from this intervention are maintained over 1 week even without continued intervention.

The Pediatric Cancer Quality of Life Inventory-32 (PCQL-32). II. Feasibility and range of measurement

The Pediatric Cancer Quality of Life Inventory-32 (PCQL-32) has been developed to be a standardized assessment instrument to assess systematically pediatric cancer patient's health-related quality of life (HRQOL) outcomes. Multidimensional serial measurement of pediatric cancer patients' HRQOL in Phase III randomized controlled clinical trials is increasingly being recognized as an essential component in evaluating the comprehensive health outcomes of modern antineoplastic treatment protocols. The 32-item PCQL-32 short form was empirically derived from the PCQL long form (84-87 items), which was administered to 291 pediatric cancer patients and their parents during various stages of treatment. The feasibility (percentage of missing values per item) and range of measurement [percentage of minimum (floor effect) and maximum (ceiling effect) possible scores] was calculated for the five PCQL-32 scales and the total scale score. Feasibility for the PCQL-32 was very good, with less than .01% missing values. Range of measurement was full, with no ceiling effects (higher symptoms/problems) and low to moderate floor effects (lower symptoms/problems). The PCQL-32 demonstrated very good feasibility and range of measurement. In its short form, the PCQL-32 is practical for Phase III clinical trials. Future studies will test the utility of the PCQL-32 as a brief serial measure for monitoring the HRQOL outcomes for children and adolescents with cancer.

The Pediatric Cancer Quality of Life Inventory (PCQL). I. Instrument development, descriptive statistics, and cross-informant variance

Intensive antineoplastic treatment protocols have been developed and implemented in controlled clinical trials with the goal of improving the survival of pediatric cancer patients. Multidimensional health outcome evaluation of this cohort of pediatric cancer patients being treated with these modern regimens is essential in order to enhance health-related quality of life. The Pediatric Cancer Quality of Life Inventory (PCQL) was developed to be a standardized assessment instrument to assess systematically pediatric cancer patient's health-related quality of life outcomes. The PCQL was administered to 291 pediatric cancer patients and their parents at various stages of treatment. The aim of the present study was to present the development, descriptive statistics, and cross-informant variance for the PCQL items. Large variability in symptoms and health-related problems were found as expected given the wide heterogeneity in the patient population sampled. Patient/parent concordance on individual items averaged in the medium effect size range. The findings underscore the importance of measuring both patient report and parent report of patient symptoms and problems in pediatric cancer health-related quality of life assessment.

The pediatric cancer quality of life inventory-32 (PCQL-32): I. Reliability and validity

BACKGROUND

Multidimensional measurement of pediatric cancer patients' health-related quality of life (HRQOL) in Phase III randomized controlled clinical trials is being recognized increasingly as an essential component in evaluating the comprehensive health outcomes of modern antineoplastic treatment protocols. The Pediatric Cancer Quality of Life Inventory-32 (PCQL-32) is a standardized patient self-report and parent proxy-report assessment instrument designed to assess systematically pediatric cancer patients' HRQOL outcomes.

METHODS

To validate a patient-report form and a parent-report form, the PCQL-32 was administered to 291 pediatric cancer patients and to their parents. Both forms yield a total score and five a priori multidimensional scales. Clinical validity was determined by the known-groups approach by comparing patients classified as either on or off treatment. To determine construct validity, a battery of standardized psychosocial measures was administered and a multitrait-multimethod matrix was constructed.

RESULTS

For both patient and parent forms, internal consistency reliability of the PCQL-32 total scale was high (0.91 and 0.92, respectively). The internal consistency reliabilities of the five component scales for both patient and parent forms were in the acceptable range for group comparisons. With regard to clinical validity, the PCQL-32 total scale and the disease/treatment and physical functioning scales of the PCQL-32 distinguished between patients on and off treatment for both patient- and parent-report. The results of the multitrait-multimethod matrix approach were consistent with hypotheses and lent evidence for the construct validity of the patient and parent forms of the PCQL-32 total scale and the psychological functioning, social functioning, cognitive functioning, physical functioning, and disease/treatment scales.

CONCLUSIONS

The PCQL-32 has demonstrated acceptable internal consistency reliability, clinical validity, and construct validity for both patient-report and parent-report forms. Further field testing of the PCQL-32 will determine its practicality and utility in multisite pediatric cancer randomized controlled clinical trials.

Family functioning predictors of adjustment in children with newly diagnosed cancer: a prospective analysis

Theoretically-driven investigations on the potentially modifiable predictors of individual differences among newly-diagnosed pediatric cancer patients may facilitate the identification of children at risk for adjustment problems. Within a risk and resistance conceptual model, family functioning was investigated concurrently and prospectively as a predictor of adjustment in newly-diagnosed pediatric cancer patients at Time 1 (within 1 month after diagnosis), Time 2 (6 months postdiagnosis), and Time 3 (9 months postdiagnosis). The family relationship dimensions of cohesion and expressiveness most consistently predicted the psychological and social adjustment of children with newly-diagnosed cancer over a 9-month period after initial diagnosis. These findings are discussed in terms of the treatment implications for enhancing child adjustment to newly-diagnosed cancer and biomedical treatment.

Perceived physical appearance and adjustment of children with newly diagnosed cancer: a path analytic model

More intensive medical treatment protocols have been initiated with the goal of improving survival of pediatric cancer patients. Evaluation of the adjustment of this cohort of children with newly diagnosed cancer being treated with these modern regimens is essential in order to enhance quality of life. Children with cancer who experience disease and treatment-related changes in physical appearance are hypothesized to be at greater risk for psychological and social adjustment problems given society's attitudes toward visible physical differences. Within a risk and resistance theoretical framework, perceived physical appearance was investigated as a predictor of depressive symptoms, social anxiety, and general self-esteem in newly diagnosed pediatric cancer patients. In support of the a priori conceptual model, path analysis findings indicate that perceived physical appearance has direct and indirect effects on depressive symptoms and social anxiety with the indirect effects mediated by general self-esteem. Exploratory analysis suggests that the effect of perceived physical appearance on general self-esteem may be attenuated by modifiable competence/adequacy domains which have implications for the development of treatment interventions for children with newly diagnosed cancer.

Perceived social support and adjustment of children with newly diagnosed cancer

The negative impact on psychologic adjustment from the stress of living with newly diagnosed cancer is hypothesized to be affected by perceived social support. Thirty children with newly diagnosed cancer completed standardized assessment instruments measuring depressive symptoms, state anxiety, trait anxiety, social anxiety, general self-esteem, and perceived social support from classmates, parents, teachers, and friends. Their parents completed a standardized assessment instrument measuring internalizing and externalizing behavior problems. Perceived classmate, parent, and teacher social support were variously correlated with the psychologic adjustment parameters in the hypothesized direction of greater support predicting lower psychologic distress and higher self-esteem. Hierarchical multiple regression analyses identified perceived classmate social support as the most consistent predictor of adaptation, providing further evidence of the essential function of the social environment of the school setting in affecting the adjustment of children with newly diagnosed cancer.

The impact of social skills training on the adjustment of children with newly diagnosed cancer

Randomized 64 children ages 5 to 13 years with newly diagnosed cancer to either a Social Skills Training experimental treatment group or a School Reintegration standard treatment group. Children who received explicit training in social skills reported higher perceived classmate and teacher social support at the 9-month follow-up in comparison to pretreatment levels, while parents reported a decrease in internalizing and externalizing behavior problems and an increase in school competence. Methodological improvements for Phase III clinical trials are addressed.

Social support and social cognitive problem-solving in children with newly diagnosed cancer

Children newly diagnosed with cancer have been documented to be at increased risk for difficulties in their return to school and ongoing positive social experiences. This article reviews the critical role of social support in helping children adjust to their illness and treatment. Social skills training for newly diagnosed children is presented as an important intervention strategy for increasing positive social interactions and overall psychosocial adjustment. A randomized, clinical research trial currently in progress that will evaluate the impact of social skills training on newly diagnosed children 5-13 years of age is delineated. The potentially positive impact of social skills training on the prevention of emotional problems and increased biologic survival are discussed.

Teacher, parent, and child evaluative ratings of a school reintegration intervention for children with newly diagnosed cancer

The disruption of school participation and accompanying social experiences because of cancer and its treatment has been related to major problems in adaptation to the disease. For the child with cancer, continuation of his/her social and academic activities provides an important opportunity to normalize as much as possible a very difficult experience. The present study reports on the children's, parents', and teachers' subjective evaluations of the benefits of a comprehensive school reintegration intervention. Forty-nine children, newly diagnosed with cancer, received comprehensive school reintegration consisting of supportive counseling, educational presentations, systematic liaison between the hospital and the school, and periodic follow-ups. Children parents, and teachers were asked to rate their perceptions of the utility and value of the intervention approach. Overall subjective evaluations were very positive, providing support for the social validity of the school reintegration approach for children with newly diagnosed cancer.

An 18-year-old with acute testicular pain. Torsion of the testicle

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Evidence for the presence of a growth factor in Dictyostelium discoideum

Polypeptide hormones, recognized for their ability to regulate cell growth and differentiation, have been classified as growth factors. These growth factors have been extensively described in higher eukaryotic organisms and cell lines [Hedin and Westermark, Cell 37:9-20, 1984]. Here we report the identification and partial characterization of a putative growth factor present in vegetative amoebae of the cellular slime mold Dictyostelium discoideum. A mutant was selected and found to be temperature sensitive due to the absence of an extracellular protein suggestive of a growth factor. The putative growth factor (DGF) is a protein resistant to both heat and strong detergent treatment but sensitive to reducing agents. The physiological significance of DGF is as yet unknown. DGF is of interest both in relation to understanding the events which control cell proliferation in Dictyostelium and in its relationship to other known growth factors.

Cognitive functioning in long-term survivors of childhood leukemia: a prospective analysis

Treatment-related cognitive impairments have been reported for survivors of childhood leukemia following prophylactic central nervous system (CNS) treatment with 2400 cGy craniospinal irradiation and intrathecal chemotherapy. The present study was designed to prospectively evaluate cognitive functioning of 24 children prior to CNS prophylaxis of 1800 cGy of craniospinal irradiation and intrathecal drugs, and at intervals of 1 and 4-5 years. At diagnosis, prior to CNS treatment, all 24 subjects performed in the average range of intelligence, as measured by the Wechsler Intelligence Scales. Subjects continued to perform in the average range with no significant declines at the 1-year follow-up. Significant declines in cognitive functioning, however, were found at the 4- to 5-year follow-up period, with five subjects (21%) performing in the low average or borderline levels of intelligence. Of the 19 subjects performing in the average range, five showed significant discrepancies between Verbal and Performance IQ scores. Nine subjects exhibited poor performance on a subtest cluster assessing perceptual and attentional processes. With regard to school experiences, 50% of the subjects had received some type of special education services. The findings indicate the need for annual evaluations of cognitive functioning in long-term survivors of childhood leukemia who received 1800 cGy craniospinal irradiation, to identify potential cognitive late effects of treatment requiring appropriate special education services.

Sterol phylogenesis and algal evolution

The stereochemistry of several sterol precursors and end products synthesized by two fungal-like micro-organisms Prototheca wickerhamii (I) and Dictyostelium discoideum (II) have been determined by chromatographic (TLC, GLC, and HPLC) and spectral (UV, MS, and 1H NMR) methods. From I and II the following sterols were isolated from the cells: cycloartenol, cyclolaudenol, 24(28)-methylenecycloartanol, ergosterol, protothecasterol, 4alpha-methylergostanol, 4alpha-methylclionastanol, clionastanol, 24beta-ethylcholesta-8,22-enol, and dictyosterol. In addition, the mechanism of C-24 methylation was investigated in both organisms by feeding to I [2-3H]lanosterol, [2-3H]cycloartenol, [24-3H]lanosterol, and [methyl-2H3]methionine and by feeding to II [methyl-2H3]methionine. The results demonstrate that the 24beta configuration is formed by different alkylation routes in I and II. The Delta25(27) route operates in I while the Delta24(28) route operates in II. Based on what is known in the literature regarding sterol distribution and phylogenesis together with our findings that the stereochemical outcome of squalene oxide cyclization leads to the production of cycloartenol rather than lanosterol (characteristic of the fungal genealogy) and the chirality of the C-24 alkyl group is similar in the two nonphotosynthetic microbes (beta oriented), we conclude that Prototheca is an apoplastic Chlorella (i.e., an alga) and that Dictyostelium as well as the other soil amoebae that synthesize cycloartenol evolved from algal rather than fungal ancestors.

A Dictyostelium discoideum mutant exhibiting calcium-dependent, high-level detergent resistance

We report the isolation of a mutant of the cellular slime mold Dictyostelium discoideum that is highly resistant to the lethal action of the nonionic detergent Triton X-100. The resistance is completely dependent on the presence of divalent cations, of which Ca2+ is the most effective.