The influence of child pain catastrophizing and parent behavior on health-related quality of life in pediatric sickle cell disease.

BACKGROUND: Literature suggests that a child's appraisal of pain and parent responses to pain are critical in predicting health-related outcomes. In youth with sickle cell disease (SCD), few investigations have examined child pain catastrophizing, and even fewer have examined the role that parents play in responding to SCD pain within the family context. The purpose of the current study was to examine the relationship between pain catastrophizing, parent response to child SCD pain, and health-related quality of life (HRQoL). PROCEDURE: The sample (N = 100) included youth with SCD (ages 8-18) and their parent. Parents completed a demographic questionnaire and the Adult Responses to Child Pain Symptoms; youth completed the Pain Catastrophizing Scale and Pediatric Quality of Life Inventory-SCD Module. RESULTS: Findings indicated that pain catastrophizing, parent minimization, and parent encouragement/monitoring significantly predicted HRQoL. Minimizing and encouragement/monitoring parent responses moderated the relationship between pain catastrophizing and HRQoL, such that parent minimizing weakened the relationship and parent encouragement/monitoring strengthened the relationship. CONCLUSIONS: Paralleling pediatric chronic pain literature, findings suggest that pain catastrophizing predicts HRQoL in youth with SCD. However, findings from moderation analyses diverge from the chronic pain literature; data suggest that encouragement/monitoring responses strengthen the negative relationship between child pain catastrophizing and HRQoL. Child pain catastrophizing and parent response to SCD pain may be appropriate targets for clinical intervention to improve HRQoL. Future studies should strive to better understand parent responses to SCD pain.

A dyadic analysis of parent and child pain catastrophizing and health-related quality of life in pediatric sickle cell disease.

ABSTRACT: The purpose of this study was to examine the dyadic and individual level effects of parent and child pain catastrophizing on child health-related quality of life (HRQOL) in pediatric sickle cell disease. Questionnaires assessing child pain frequency, child and parent pain catastrophizing, and child HRQOL were completed by youth and their primary caregiver. A Common Fate Model was estimated to test the dyadic level relationship between parent and child pain catastrophizing and child HRQOL. An Actor-Partner-Common Fate Model hybrid was estimated to test the relationship between child HRQOL and individual-level child pain catastrophizing and parent pain catastrophizing, respectively. In each model, child HRQOL was modelled as a dyadic variable by factoring parent and child ratings. Patients (N = 100, M age = 13.5 years, 61% female) and their caregivers (M age = 41.8 years, 86% mothers) participated. Dyad-level pain catastrophizing was negatively associated with child HRQOL, demonstrating a large effect (ß = -0.809). Individual-level parent and child pain catastrophizing were each uniquely negatively associated with child HRQOL, demonstrating small to medium effects (ß = -0.309, ß = -0.270). Individual level effects were net of same-rater bias, which was significant for both parents and children. Both the unique and the overlapping aspects of parent and child pain catastrophizing are significant contributors to associations with child HRQOL, such that higher levels of pain catastrophizing are associated with worse child HRQOL. Findings suggest the need for multipronged intervention targeting factors common to parent-child dyads and factors unique to parents and children, respectively.

Pain and QOL in Pediatric Sickle Cell Disease: Buffering by Resilience Processes.

OBJECTIVE: Sickle cell disease (SCD) is a group of inherited blood disorders. The central feature of this chronic condition is pain. Several identified risk factors exacerbate the impact of pain on quality of life (QOL) in SCD; however, there are relatively fewer investigations of strengths-based resilience variables that might buffer the influence of pain on living with SCD. The purpose of this study was to examine strength-based resilience processes in youth with SCD and their parents. Grounded in an ecological resilience-risk model, we evaluated whether adolescent and parent protective factors (pain acceptance, mindfulness, and psychological flexibility) moderated the relation between adolescent-reported pain burden and QOL. METHODS: Ninety-three 12- to 18-year-old adolescents with SCD and their parents participated. Adolescents completed assessments of pain characteristics, pain acceptance, mindfulness, and QOL. Parents completed instruments measuring demographic and disease variables and parent psychological flexibility. RESULTS: Pain variables were associated with protective factors in predicted directions. Adolescent acceptance and mindfulness were positively correlated with QOL. Parent psychological flexibility and adolescent QOL were not related. After controlling for demographic, pain, and disease variables, moderation analyses indicated that adolescent pain acceptance buffered the relation between SCD pain burden and QOL. Moderation analyses were not significant for adolescent mindfulness or parent psychological flexibility. CONCLUSIONS: Results suggest that strengths-based factors may play an important role for adolescents' QOL within the context of SCD pain. Interventions that enhance teenagers' ability to accept pain might be particularly useful to improve QOL in adolescents living with SCD pain.

Risk factors, etiologies, and comorbidities in urban pediatric epilepsy.

The Seizures and Outcomes Study in Children (SOS-KIDS) identifies risk factors, etiologies, and comorbidities in a pediatric epilepsy population in a major city with diversity in socioeconomic levels. A thorough understanding of the range of issues impacting children with epilepsy is critical to establishing treatment that will produce better health outcomes. SOS-KIDS is a cross-sectional cohort study of pediatric epilepsy patients who live in Washington D.C. and are evaluated at Children's National Hospital. Families were recruited at the time of the child's routine clinic appointment or inpatient visit. Information was extracted from participants' electronic medical records (EMR) and parent reports; participants were screened for comorbidities using standardized screening measures. Data were collected from 289 participants (47% female, 53% male), and mean age was 7.9 years (2 months to 17 years). Twenty-nine percent of participants had primary generalized epilepsy, 63% focal epilepsy, 0.3% combined generalized and focal epilepsy, and 8% could not be distinguished. There were a variety of epilepsy risk factors including prematurity (10%), intraventricular hemorrhage (7%), neonatal seizures (8%), and febrile seizures (17%). The most common etiologies were cerebral malformations (13%) and genetic disorders (25%). Numerous participants had documented comorbidities including developmental delay (56%), intellectual disability (20%), headaches (16%), attention-deficit hyperactivity disorder (23%), and autism (7%). Of participants aged six years and older, depression, and anxiety were reported in 5% and 6% within the EMR, 14% and 19% in parent surveys, and 22% and 33% with standardized screening measures. We identified a wide variety of risk factors and etiologies among urban pediatric epilepsy patients, with genetic and structural being the most common. Neurologic and psychiatric comorbidities were common, but the prevalence of several psychiatric disorders reported within the EMR was substantially lower compared to that found when using parent surveys and standardized screening measures.

Stressful life events, depression, and the moderating role of psychophysiological reactivity in patients with pediatric inflammatory bowel disease.

OBJECTIVE: The development of depressive symptoms in youth with IBD is a concerning disease complication, as higher levels of depressive symptoms have been associated with poorer quality of life and lower medication adherence. Previous research has examined the association between disease activity and depression, but few studies have examined individual differences in experience of stressful life events in relation to depressive symptoms. The purpose of the current study is to examine the relation between stressful life events and depression within pediatric IBD and to determine whether individual differences in stress response moderates this association. METHODS: 56 youth ages 8-17 years old diagnosed with IBD completed questionnaires about their depressive symptoms and history of stressful life events. We assessed skin conductance reactivity (SCR) to a stressful task as an index of psychophysiological reactivity. RESULTS: Stressful life events (r = 0.36, p = .007) were positively related to depressive symptoms. Youth who demonstrated a greater maximum SC level during the IBD-specific stress trial compared to baseline (n = 32) reported greater depressive symptoms. For these same participants, the relationship between stressful life events and depressive symptoms depended on SCR F(3, 28) = 4.23, p = .01, such that at moderate and high levels of SCR, a positive relationship between stressful life events and depressive symptoms was observed. CONCLUSIONS: The relationship between stressful life events and depressive symptoms in youth with IBD may depend on individual differences in processing stress, such that risk may increase with greater psychophysiological reactivity.

Temperament and Health-Related Quality of Life in Newly Diagnosed Pediatric Inflammatory Bowel Disease.

OBJECTIVE: Health-related quality of life (HRQOL) is typically examined from a deficit standpoint, meaning that little is known about factors associated with higher HRQOL in pediatric illness samples. The aim of the current study was to investigate demographic, disease, and temperamental factors associated with child and parent-report of HRQOL in youth newly diagnosed with inflammatory bowel disease (IBD). METHODS: Participants included 52 youth ages 8-17 diagnosed with IBD and their caregivers who each completed ratings of the child's HRQOL. Parents rated their child's emotional reactivity, conceptualized as a temperamental risk factor, and adaptability, conceptualized as a temperamental protective factor. Disease symptoms were rated by youth, and physician global assessment of disease activity was obtained. RESULTS: HRQOL was rated lower by children and their parents as self-reported disease symptoms and parent-rated emotional reactivity increased. Conversely, total HRQOL was higher for children with higher parent-ratings of adaptability. In multiple regression analyses, higher levels of adaptability along with male sex and lower child-reported disease symptoms were associated with higher child and parent-reported HRQOL. CONCLUSIONS: Higher HRQOL at time of diagnosis in pediatric IBD is associated with greater adaptability when accounting for variability due to child sex and disease symptoms. Consideration of temperament, including emotional reactivity and adaptability, may offer insight into patients' typical ways of responding when stressed and provide preliminary information about factors related to post-diagnosis HRQOL. Attention should be given to both protective and risk factors to inform future intervention development, including strengths-based approaches.

Pica in Pediatric Sickle Cell Disease.

Pica is the developmentally inappropriate consumption of non-nutritive items for at least one month. Pica can lead to many adverse outcomes, but the exact pathophysiology of pica is unknown or variable across populations. Several studies have evidenced that there is a high prevalence of pica among youth with sickle cell disease (SCD). However, the lack of knowledge regarding the correlates of pica contributes to overlooking the condition, inaccurate diagnoses, and a lack of evidence-based treatments once pica is identified. This review examines the literature to develop a biopsychosocial model of pica in SCD. Elucidating the potential relationships among the proposed biological, psychological, and social factors, and pica will inform our understanding of this phenomenon in pediatric SCD and may guide future research and clinical recommendations.

Age, Disease Symptoms, and Depression are Associated With Body Image Dissatisfaction in Newly Diagnosed Pediatric Inflammatory Bowel Disease.

OBJECTIVES: Body image refers to the subjective, mental representation one makes regarding their physical appearance. Children and adolescents with inflammatory bowel disease (IBD) may be prone to experiencing negative self-evaluations regarding their body image given disease-related symptoms and treatment side-effects. In this study, we aimed to examine demographic, medical, and psychosocial variables related to body image dissatisfaction (BID) in pediatric patients diagnosed with IBD and to determine which variables are most predictive of higher dissatisfaction. METHODS: A total of 52 youth newly diagnosed with IBD (Crohn's disease, ulcerative colitis, indeterminate colitis) ages 8 to 17 years completed questionnaires regarding their psychosocial functioning (ie, depression, anxiety, health-related quality of life, stress), disease symptoms, and BID. BID was assessed using the modified Adapted Satisfaction with Appearance questionnaire, yielding a total score and subscale scores assessing Perceived Social Impact and Subjective Dissatisfaction. Physician global assessment of disease activity and demographic and medical characteristics were abstracted from electronic chart review. RESULTS: Youth endorsed low overall BID concerns but noted the highest dissatisfaction with their abdomen, chest, and arms. Older child age, greater patient-reported disease symptoms, and worse depression symptoms were most strongly associated with overall body dissatisfaction when evaluated in a hierarchical regression model. CONCLUSIONS: Demographic, disease-related, and psychosocial factors are associated with BID in youth newly diagnosed with IBD. Given associations between BID and adverse health outcomes in healthy youth, these findings highlight a unique opportunity to improve screening and interventions for BID in patients with IBD.

Parent and Family Functioning in Pediatric Inflammatory Bowel Disease.

Although the impact of pediatric inflammatory bowel disease (IBD) extends beyond the patient to their parents and families, the focus of previous literature has largely been on investigating the patient's medical and psychosocial functioning, with less consideration of the family system. Having a comprehensive understanding of parent and family functioning within the context of pediatric IBD is important given the role parents and family members have in the successful management of the disease and caring of the child. The current review paper aggregates the empirical research regarding parent and family functioning, including comparisons to normative samples, other illness groups, and how functioning relates to child psychosocial and health outcomes. Extant literature on parents and families in pediatric IBD has largely focused on the variables of parenting stress, parent psychosocial functioning, parent quality of life, and family functioning. Summary findings elucidate the complex relationships between parents, families, and children affected by IBD and highlight the importance of assessing parent and family functioning within pediatric IBD. The current review also offers implications for clinical practice, notes the limitations of the present literature, and provides recommendations for future research.

A Systematic Review of Medication Adherence Interventions in Pediatric Sickle Cell Disease.

OBJECTIVE: Adherence to medication regimens is of critical importance in sickle cell disease (SCD). Most notably, data indicate that hydroxyurea, penicillin, and iron chelators increase life expectancy and decrease comorbid medical problems (e.g., strokes). However, average pediatric SCD adherence rates are only 55-74%. Studies have introduced interventions for pediatric SCD adherence, but no review has synthesized these data. METHODS: We conducted a systematic review of interventions for enhancing medication adherence in pediatric SCD. There were 9 studies that met inclusion and exclusion criteria. The Pediatric Self-Management Model provided a framework for organizing the modifiable factors targeted by existing interventions. RESULTS: The 9 studies had high risk of bias levels and most targeted hydroxyurea. All studies used multiple measures of adherence, the interventions were multicomponent, and most included behavioral or technological interventions. There was variability in terms of whether the intervention targeted the individual, family, community, or healthcare system. CONCLUSIONS: Consistent with the broader adherence literature, targeting knowledge alone was insufficient in increasing adherence. Findings suggest that reminders and targeting self-efficacy were key to success. In addition, addressing multiple domains in an intervention yielded larger effects on adherence. Although these results are promising, this review highlights several limitations of the extant literature, including a paucity of intervention studies and several methodological weaknesses, such as small sample sizes, few randomized controlled trials, and variable measures of adherence. Recommendations for advancing scientific understanding of adherence promoting interventions in pediatric SCD are provided.

Parent IMPACT-III: Development and Validation of an Inflammatory Bowel Disease-specific Health-related Quality-of-life Measure.

OBJECTIVES: The present study aimed to validate the parent-proxy IMPACT-III (IMPACT-III-P) in a sample of youth diagnosed with inflammatory bowel disease (IBD). Parent-proxy report measures are standard for pediatric psychosocial assessment, and the IMPACT-III-P will provide a more comprehensive representation of HRQOL. Reliability and validity analyses were conducted. METHODS: Parents (N = 50) of youth 8 to 17 years with IBD reported on their child's HRQOL (IMPACT-III-P and PedsQL-4.0) and depression (BASC-2); youth reported on their HRQOL (child IMPACT-III), pain interference (PROMIS Pain Interference), and disease symptoms; and physicians completed measures of disease activity. RESULTS: Criterion validity was established as the IMPACT-III-P was strongly, positively associated with the PedsQL (r = 0.59, P < 0.001). Convergent validity was supported as higher IMPACT-III-P scores were associated with less pain interference (r = -0.41, P < 0.01) and lower depression (r = -0.41, P < 0.01). Discriminant validity was partially supported, as higher IMPACT-III-P scores were associated with lower child-reported symptoms (r = -0.41, P < 0.01), but scores did not differ based on inactive, mild, or moderate/severe disease activity groups as rated by physicians. Internal consistency, parent-child agreement, and item-level analyses revealed strong reliability. CONCLUSIONS: The IMPACT-III-P demonstrated strong validity and reliability. Parents and children had similar reports of HRQOL, with parents rating child HRQOL slightly lower. Findings support the use of the IMPACT-III-P for youth 8 to 17 years old to use in accordance with the child IMPACT-III to provide valuable information regarding HRQOL in youth with IBD.

Topical Review: State of the Field of Child Self-Report of Acute Pain.

OBJECTIVE: Children experience acute pain with routine and emergent healthcare, and untreated pain can lead to a range of repercussions. Assessment is vital to diagnosing and treating acute pain. Given the internal nature of pain, self-report is predominant. This topical review reflects on the state of the field of pediatric acute pain self-report, and proposes a framework for acute pain assessment via self-report. METHOD: We examine self-report of acute pain in preschool-age children through adolescents, and we detail a three-step process to optimize acute pain assessment. RESULTS: The first step is to decide between a pain screening or assessment. Several 0-10 self-report scales are available for pain screenings. Assessment requires specification of the goals and domains to target. Core criteria, common features, modulating factors, and consequences of acute pain provide a framework for a comprehensive pain assessment. Whereas there are some measures available to assess aspects of these domains, there are considerable gaps. Last, it is important to integrate the data to guide clinical care of acute pain. CONCLUSIONS: Self-report of acute pain is dominated by single-item intensity scales, which are useful for pain screening but inadequate for pain assessment. We propose a three-step approach to acute pain assessment in children. However, there is a need for measure development for a comprehensive evaluation of the core criteria, common features, modulating factors, and consequences of pediatric acute pain. In addition, there is limited guidance in merging data found in multifaceted evaluations of pediatric acute pain.

Everyday executive function in focal onset pediatric epilepsy on the parent-report BRIEF2.

Executive function (EF) difficulties are a core neuropsychological feature of pediatric epilepsy, and parent-report measures of EF concerns are an important complement to task-based EF measures. The Behavior Rating Inventory of Executive Function (BRIEF) has shown sensitivity to parent-reported EF concerns in epilepsy and other pediatric populations. We compared profiles of parent-reported EF concerns using the BRIEF and its revision, the BRIEF2, in 117 pediatric patients with focal onset epilepsy to examine the clinical utility of the revised scale. We then compared BRIEF2 profiles between patients and age- and gender-matched healthy controls. Among patients, profiles on the BRIEF did not globally differ from the BRIEF2, and agreement was very good across scales. Patients and controls differed significantly on the BRIEF2, with patients showing higher EF difficulties reported by parents across most scales. High rates of clinical elevation among patients emerged on the Task Monitor, Plan/Organize, Working Memory, and Shift scales. Younger age of epilepsy onset, chronic epilepsy, and right hemisphere seizure focus were associated with higher parent-reported EF concerns. Findings suggest that the BRIEF2 demonstrates similar performance to the BRIEF among pediatric patients with focal onset epilepsy who are most at risk in the areas of task monitoring, working memory, planning and organization, and flexibility. These findings are informative when comparing literature across versions and provide additional insight into the nature of parent-reported EF difficulties among children with focal onset epilepsy.

Parent-Child Behavioral Interactions during Pediatric Immunizations in a Latino Sample.

A number of studies have found that specific parent behaviors are strong predictors of child medical procedural distress or coping. These findings have informed treatment protocols to lower children's distress during invasive medical events. However, the vast majority of this research has been conducted on predominately North American, English-speaking, Caucasian samples. One growing population that faces healthcare disparities is Latinos living in the U.S. The purpose of this study was to explore the types and frequencies of parent and child behavior, as well as the association between parent behavior and child distress and coping in a sample of Spanish-speaking Latino-American parent-child dyads. Nineteen 4- to 6-year-old Latino children receiving routine immunizations and their parents were video recorded, and behaviors were coded with commonly used schemes. The findings suggest that there may be differences in Latino parent and child behavior when compared to the extant - predominately English-speaking, Caucasian North American - literature. This study provides an initial examination of how cultural constructs may relate to parent-child behavior in Spanish-speaking Latino families in the U.S. Future research is warranted as findings can inform culturally sensitive clinical practice.

Decrease in hyperosmotic stress-induced corneal epithelial cell apoptosis by L-carnitine.

PURPOSE: To characterize the osmoprotective properties of L-carnitine on human corneal epithelial cell volume and apoptosis during hyperosmotic stress. METHODS: Human corneal limbal epithelial (HCLE) cells were exposed to culture medium at 300 mOsm (isotonic) or 500 mOsm (hyperosmotic) with or without L-carnitine (10 mM). Induction of apoptosis was detected by quantifying the proteolytic activity of caspase-8, caspase-9, and caspase-3/7 using caspase activity assays, the expression of tumor necrosis factor (TNF)-α with enzyme-linked immunosorbent assay, and annexin V/propidium iodide staining of HCLE cells evaluated with confocal microscopy and flow cytometry. Cell volume changes in response to hyperosmotic stress were analyzed using flow cytometry. RESULTS: After the HCLE cells were exposed to hyperosmotic medium (500 mOsm), the percentage of shrunken cells and damaged/dead cells (stained positively for annexin V and/or propidium iodide) was six- and three-fold, respectively, higher than that under isotonic conditions (300 mOsm). This was paralleled by an increase in TNF-α concentration in media and caspase-8, -9, and -3/7 activities (six-, four-, ten-, and twelve-fold, respectively; all showing p < 0.001). Addition of L-carnitine during hyperosmotic stress partly restored cell volume and significantly reduced the concentration of TNF-α released (p = 0.005) and caspase-9 activity (p = 0.0125). Addition of L-carnitine reduced the percentage of hyperosmolarity-induced damaged/dead cells to levels observed under isotonic conditions. CONCLUSIONS: L-carnitine can regulate human corneal epithelial cell volume under hyperosmotic stress and ameliorate hyperosmotic stress-induced apoptosis.

Betaine stabilizes cell volume and protects against apoptosis in human corneal epithelial cells under hyperosmotic stress.

Elevated tear osmolarity is one of the key pathological factors in dry eye leading to ocular discomfort associated with damage to the ocular surface and inflammation. The aim of this study was to determine the capacity of the organic osmolyte, betaine, to act as an osmoprotectant against hypertonic stress-induced human corneal epithelial cell shrinkage and apoptosis using in vitro cell culture models. Human corneal limbal epithelial (HCLE) cells exposed to culture medium for 16 h at 300 mOsm (isotonic) or 500 mOsm (hyperosmotic) in the presence or absence of betaine (5 or 10 mM) were evaluated for cell volume changes; cell viability; and apoptosis. Betaine (10 mM) ameliorated hyperosmotically induced reduction of cell volume (from 27% reduction to 11%) and resulted in increased mitochondrial activity (by 17%) and an increase in viable cell numbers (by 12%) compared to controls (exposure to hyperosmotic medium without betaine). Hyperosmotically shocked HCLE cells in the presence of betaine (10 mM) halved the number of damaged cells (apoptotic/necrotic) compared to cells in the absence of betaine. The presence of betaine (at 5 or 10 mM) significantly reduced the activity of caspase-8, -9 and -3/7 and release of TNF-α was also reduced by 34% or 55% after exposure of HCLE to 500 mOsm in the presence of 5 or 10 mM betaine, respectively. Using polyclonal antibody against Betaine/GABA transporter 1 (BGT-1), we detected the presence of BGT-1 in HCLE. We demonstrated that the transport of betaine was facilitated by increased osmolarity. In conclusion, betaine stabilized corneal epithelial cell volume under hyperosmotic stress and limited hyperosmotic stress-induced HCLE apoptosis.

In vitro propagation of plant virus using different forms of plant tissue culture and modes of culture operation.

Plant virus accumulation was investigated in vitro using three different forms of plant tissue culture. Suspended cells, hairy roots and shooty teratomas of Nicotiana benthamiana were infected with tobacco mosaic virus (TMV) using the same initial virus:biomass ratio. Viral infection did not affect tissue growth or morphology in any of the three culture systems. Average maximum virus concentrations in hairy roots and shooty teratomas were similar and about an order of magnitude higher than in suspended cells. Hairy roots were considered the preferred host because of their morphological stability in liquid medium and relative ease of culture. The average maximum virus concentration in the hairy roots was 0.82+/-0.14 mg g(-1) dry weight; viral coat protein represented a maximum of approximately 6% of total soluble protein in the biomass. Virus accumulation in hairy roots was investigated further using different modes of semi-continuous culture operation aimed at prolonging the root growth phase and providing nutrient supplementation; however, virus concentrations in the roots were not enhanced compared with simple batch culture. The relative infectivity of virus in the biomass declined by 80-90% during all the cultures tested, irrespective of the form of plant tissue used or mode of culture operation. Hairy root cultures inoculated with a transgenic TMV-based vector in batch culture accumulated green fluorescent protein (GFP); however, maximum GFP concentrations in the biomass were relatively low at 39 microg g(-1) dry weight, probably due to genetic instability of the vector. This work highlights the advantages of using hairy roots for in vitro propagation of TMV compared with shooty teratomas and suspended plant cells, and demonstrates that batch root culture is more effective than semi-continuous operations for accumulation of high virus concentrations in the biomass.

Foreign protein production using plant cell and organ cultures: Advantages and limitations.

Plants and plant tissue cultures are used as host systems for expression of foreign proteins including antibodies, vaccines and other therapeutic agents. Recombinant or stably transformed plants and plant cell cultures have been applied for foreign protein production for about 20 years. Because the product concentration achieved exerts a major influence on process economics, considerable efforts have been made by commercial and academic research groups to improve foreign protein expression levels. However, post-synthesis product losses due to protease activity within plant tissues and/or extracellular protein adsorption in plant cell cultures can negate the benefits of molecular or genetic enhancement of protein expression. Transient expression of foreign proteins using plant viral vectors is also a practical approach for producing foreign proteins in plants. Adaptation of this technology is required to allow infection and propagation of engineered viruses in plant tissue cultures for transient protein expression in vitro.