Epigenetic balance ensures mechanistic control of MLL amplification and rearrangement.

MLL/KMT2A amplifications and translocations are prevalent in infant, adult, and therapy-induced leukemia. However, the molecular contributor(s) to these alterations are unclear. Here, we demonstrate that histone H3 lysine 9 mono- and di-methylation (H3K9me1/2) balance at the MLL/KMT2A locus regulates these amplifications and rearrangements. This balance is controlled by the crosstalk between lysine demethylase KDM3B and methyltransferase G9a/EHMT2. KDM3B depletion increases H3K9me1/2 levels and reduces CTCF occupancy at the MLL/KMT2A locus, in turn promoting amplification and rearrangements. Depleting CTCF is also sufficient to generate these focal alterations. Furthermore, the chemotherapy doxorubicin (Dox), which associates with therapy-induced leukemia and promotes MLL/KMT2A amplifications and rearrangements, suppresses KDM3B and CTCF protein levels. KDM3B and CTCF overexpression rescues Dox-induced MLL/KMT2A alterations. G9a inhibition in human cells or mice also suppresses MLL/KMT2A events accompanying Dox treatment. Therefore, MLL/KMT2A amplifications and rearrangements are controlled by epigenetic regulators that are tractable drug targets, which has clinical implications.

Talin-Dependent Integrin Activation Regulates VE-Cadherin Localization and Endothelial Cell Barrier Function.

RATIONALE: Endothelial barrier function depends on the proper localization and function of the adherens junction protein VE (vascular endothelial)-cadherin. Previous studies have suggested a functional relationship between integrin-mediated adhesion complexes and VE-cadherin yet the underlying molecular links are unclear. Binding of the cytoskeletal adaptor protein talin to the ß-integrin cytoplasmic domain is a key final step in regulating the affinity of integrins for extracellular ligands (activation) but the role of integrin activation in VE-cadherin mediated endothelial barrier function is unknown. OBJECTIVE: To test the requirement of talin-dependent activation of ß1 integrin in VE-cadherin organization and endothelial cell (EC) barrier function. METHODS AND RESULTS: EC-specific deletion of talin in adult mice resulted in impaired stability of intestinal microvascular blood vessels, hemorrhage, and death. Talin-deficient endothelium showed altered VE-cadherin organization at EC junctions in vivo. shRNA (short hairpin RNA)-mediated knockdown of talin1 expression in cultured ECs led to increased radial actin stress fibers, increased adherens junction width and increased endothelial monolayer permeability measured by electrical cell-substrate impedance sensing. Restoring ß1-integrin activation in talin-deficient cells with a ß1-integrin activating antibody normalized both VE-cadherin organization and EC barrier function. In addition, VE-cadherin organization was normalized by reexpression of talin or integrin activating talin head domain but not a talin head domain mutant that is selectively deficient in activating integrins. CONCLUSIONS: Talin-dependent activation of EC ß1-integrin stabilizes VE-cadherin at endothelial junctions and promotes endothelial barrier function.

Lis1 mediates planar polarity of auditory hair cells through regulation of microtubule organization.

The V-shaped hair bundles atop auditory hair cells and their uniform orientation are manifestations of epithelial planar cell polarity (PCP) required for proper perception of sound. PCP is regulated at the tissue level by a conserved core Wnt/PCP pathway. However, the hair cell-intrinsic polarity machinery is poorly understood. Recent findings implicate hair cell microtubules in planar polarization of hair cells. To elucidate the microtubule-mediated polarity pathway, we analyzed Lis1 function in the auditory sensory epithelium in the mouse. We show that conditional deletion of Lis1 in developing hair cells causes defects in cytoplasmic dynein and microtubule organization, resulting in planar polarity defects without overt effects on the core PCP pathway. Lis1 ablation during embryonic development results in defects in hair bundle morphology and orientation, cellular organization and junctional nectin localization. We present evidence that Lis1 regulates localized Rac-PAK signaling in embryonic hair cells, probably through microtubule-associated Tiam1, a guanine nucleotide exchange factor for Rac. Lis1 ablation in postnatal hair cells significantly disrupts centrosome anchoring and the normal V-shape of hair bundles, accompanied by defects in the pericentriolar matrix and microtubule organization. Lis1 is also required for proper positioning of the Golgi complex and mitochondria as well as for hair cell survival. Together, our results demonstrate that Lis1 mediates the planar polarity of hair cells through regulation of microtubule organization downstream of the tissue polarity pathway.

The vertebrate-specific Kinesin-6, Kif20b, is required for normal cytokinesis of polarized cortical stem cells and cerebral cortex size.

Mammalian neuroepithelial stem cells divide using a polarized form of cytokinesis, which is not well understood. The cytokinetic furrow cleaves the cell by ingressing from basal to apical, forming the midbody at the apical membrane. The midbody mediates abscission by recruiting many factors, including the Kinesin-6 family member Kif20b. In developing embryos, Kif20b mRNA is most highly expressed in neural stem/progenitor cells. A loss-of-function mutant in Kif20b, magoo, was found in a forward genetic screen. magoo has a small cerebral cortex, with reduced production of progenitors and neurons, but preserved layering. In contrast to other microcephalic mouse mutants, mitosis and cleavage furrows of cortical stem cells appear normal in magoo. However, apical midbodies show changes in number, shape and positioning relative to the apical membrane. Interestingly, the disruption of abscission does not appear to result in binucleate cells, but in apoptosis. Thus, Kif20b is required for proper midbody organization and abscission in polarized cortical stem cells and has a crucial role in the regulation of cerebral cortex growth.

Pulmonary Arterial Stiffness: Toward a New Paradigm in Pulmonary Arterial Hypertension Pathophysiology and Assessment.

Stiffening of the pulmonary arterial bed with the subsequent increased load on the right ventricle is a paramount feature of pulmonary hypertension (PH). The pathophysiology of vascular stiffening is a complex and self-reinforcing function of extracellular matrix remodeling, driven by recruitment of circulating inflammatory cells and their interactions with resident vascular cells, and mechanotransduction of altered hemodynamic forces throughout the ventricular-vascular axis. New approaches to understanding the cell and molecular determinants of the pathophysiology combine novel biopolymer substrates, controlled flow conditions, and defined cell types to recapitulate the biomechanical environment in vitro. Simultaneously, advances are occurring to assess novel parameters of stiffness in vivo. In this comprehensive state-of-art review, we describe clinical hemodynamic markers, together with the newest translational echocardiographic and cardiac magnetic resonance imaging methods, to assess vascular stiffness and ventricular-vascular coupling. Finally, fluid-tissue interactions appear to offer a novel route of investigating the mechanotransduction processes and disease progression.

Cerebral cavernous malformations arise independent of the heart of glass receptor.

BACKGROUND AND PURPOSE: The Heart of Glass (HEG) receptor binds KRIT1 and functions with KRIT1, CCM2, and PDCD10 in a common signaling pathway required for heart and vascular development. Mutations in KRIT1, CCM2, and PDCD10 also underlie human cerebral cavernous malformation (CCM) and postnatal loss of these genes in the mouse endothelium results in rapid CCM formation. Here, we test the role of HEG in CCM formation in mice and in humans. METHODS: We constitutively or conditionally deleted Heg and Ccm2 genes in genetically modified mice. Mouse embryos, brain, and retina tissues were analyzed to assess CCM lesion formation. RESULTS: In postnatal mice, CCMs form with Ccm2-/- but not with Heg-/- or Heg-/-;Ccm2+/- endothelial cells. Consistent with these findings, human patients with CCM who lack exonic mutations in KRIT1, CCM2, or PDCD10 do not have mutations in HEG. CONCLUSIONS: These findings suggest that the HEG-CCM signaling functions during cardiovascular development and growth, whereas CCMs arise because of loss of HEG-independent CCM signaling in the endothelium of the central nervous system after birth.

Testin interacts with vangl2 genetically to regulate inner ear sensory cell orientation and the normal development of the female reproductive tract in mice.

BACKGROUND: Planar cell polarity (PCP) signaling regulates the coordinated polarization of cells and is required for the normal development and function of many tissues. Previous studies have identified conserved PCP genes, such as Van Gogh-like 2 (Vangl2) and Prickle (Pk), in the regulation of coordinated orientation of inner ear hair cells and female reproductive tract development. Testin shares a PET-LIM homology with Pk. It is not clear whether Testin acts in PCP processes in mammals. RESULTS: We identified Testin as a Vangl2-interacting protein through a 2-hybrid screen with a cochlea cDNA library. Testin is enriched to cell-cell boundaries in the presence of Vangl2 in cultured cells. Genetic inactivation of Testin leads to abnormal hair cell orientation in the vestibule and cellular patterning defects in the cochlea. In addition, Testin genetically interacts with Vangl2 to regulate hair cell orientation in the cochlea and the opening of the vaginal tract. CONCLUSIONS: Our findings suggested Testin as a gene involved in coordinated hair cell orientation in the inner ear and in female reproductive tract development. Furthermore, its genetic interaction with Vangl2 implicated it as a potential molecular link, responsible for mediating the role of Vangl2-containing membranous PCP complexes in directing morphologic polarization.

Redundant functions of Rac GTPases in inner ear morphogenesis.

Development of the mammalian inner ear requires coordination of cell proliferation, cell fate determination and morphogenetic movements. While significant progress has been made in identifying developmental signals required for inner ear formation, less is known about how distinct signals are coordinated by their downstream mediators. Members of the Rac family of small GTPases are known regulators of cytoskeletal remodeling and numerous other cellular processes. However, the function of Rac GTPases in otic development is largely unexplored. Here, we show that Rac1 and Rac3 redundantly regulate many aspects of inner ear morphogenesis. While no morphological defects were observed in Rac3(-/-) mice, Rac1(CKO); Rac3(-/-) double mutants displayed enhanced vestibular and cochlear malformations compared to Rac1(CKO) single mutants. Moreover, in Rac1(CKO); Rac3(-/-) mutants, we observed compromised E-cadherin-mediated cell adhesion, reduced cell proliferation and increased cell death in the early developing otocyst, leading to a decreased size and malformation of the membranous labyrinth. Finally, cochlear extension was severely disrupted in Rac1(CKO); Rac3(-/-) mutants, accompanied by a loss of epithelial cohesion and formation of ectopic sensory patches underneath the cochlear duct. The compartmentalized expression of otic patterning genes within the Rac1(CKO); Rac3(-/-) mutant otocyst was largely normal, however, indicating that Rac proteins regulate inner ear morphogenesis without affecting cell fate specification. Taken together, our results reveal an essential role for Rac GTPases in coordinating cell adhesion, cell proliferation, cell death and cell movements during otic development.

Statins repress hedgehog signaling in medulloblastoma with no bone toxicities.

The Hedgehog (Hh) pathway plays an indispensable role in bone development and genetic activation of the pathway results in medulloblastoma (MB), the most common malignant brain tumor in children. Inhibitors of Hh pathway (such as vismodegib and sonedigib), which are used to treat MB, cause irreversible defects in bone growth in young children. Cholesterol is required for the activation of the Hh pathway, and statins, inhibitors of cholesterol biosynthesis, suppress MB growth by repressing Hh signaling in tumor cells. Here, we investigate the role of cholesterol biosynthesis in the proliferation and Hh signaling in chondrocytes, and examine the bone development in mice after statin treatment. Statins significantly inhibited MB growth in young mice, but caused no defects in bone development. Conditional deletion of NADP steroid dehydrogenase-like (NSDHL), an enzyme necessary for cholesterol biosynthesis, suppressed cholesterol synthesis in chondrocytes, and disrupted the growth plate in mouse femur and tibia, indicating the important function of intracellular cholesterol in bone development. Hh pathway activation and the proliferation of chondrocytes were inhibited by statin treatment in vitro; however, statins did not impair bone growth in vivo due to insufficient penetration into the bone. Our studies reveal a critical role of cholesterol in bone development, and support the utilization of statins for treatment of MB as well as other Hh pathway-associated malignancies.

The small GTPase Rac1 regulates auditory hair cell morphogenesis.

Morphogenesis of sensory hair cells, in particular their mechanotransduction organelle, the stereociliary bundle, requires highly organized remodeling of the actin cytoskeleton. The roles of Rho family small GTPases during this process remain unknown. Here we show that deletion of Rac1 in the otic epithelium resulted in severe defects in cochlear epithelial morphogenesis. The mutant cochlea was severely shortened with a reduced number of auditory hair cells and cellular organization of the auditory sensory epithelium was abnormal. Rac1 mutant hair cells also displayed defects in planar cell polarity and morphogenesis of the stereociliary bundle, including bundle fragmentation or deformation, and mispositioning or absence of the kinocilium. We further demonstrate that a Rac-PAK (p21-activated kinase) signaling pathway mediates kinocilium-stereocilia interactions and is required for cohesion of the stereociliary bundle. Together, these results reveal a critical function of Rac1 in morphogenesis of the auditory sensory epithelium and stereociliary bundle.

VE-cadherin endocytosis controls vascular integrity and patterning during development.

Tissue morphogenesis requires dynamic intercellular contacts that are subsequently stabilized as tissues mature. The mechanisms governing these competing adhesive properties are not fully understood. Using gain- and loss-of-function approaches, we tested the role of p120-catenin (p120) and VE-cadherin (VE-cad) endocytosis in vascular development using mouse mutants that exhibit increased (VE-cadGGG/GGG) or decreased (VE-cadDEE/DEE) internalization. VE-cadGGG/GGG mutant mice exhibited reduced VE-cad-p120 binding, reduced VE-cad levels, microvascular hemorrhaging, and decreased survival. By contrast, VE-cadDEE/DEE mutants exhibited normal vascular permeability but displayed microvascular patterning defects. Interestingly, VE-cadDEE/DEE mutant mice did not require endothelial p120, demonstrating that p120 is dispensable in the context of a stabilized cadherin. In vitro, VE-cadDEE mutant cells displayed defects in polarization and cell migration that were rescued by uncoupling VE-cadDEE from actin. These results indicate that cadherin endocytosis coordinates cell polarity and migration cues through actin remodeling. Collectively, our results indicate that regulated cadherin endocytosis is essential for both dynamic cell movements and establishment of stable tissue architecture.

An isoform-selective, small-molecule inhibitor targets the autoregulatory mechanism of p21-activated kinase.

Autoregulatory domains found within kinases may provide more unique targets for chemical inhibitors than the conserved ATP-binding pocket targeted by most inhibitors. The kinase Pak1 contains an autoinhibitory domain that suppresses the catalytic activity of its kinase domain. Pak1 activators relieve this autoinhibition and initiate conformational rearrangements and autophosphorylation events leading to kinase activation. We developed a screen for allosteric inhibitors targeting Pak1 activation and identified the inhibitor IPA-3. Remarkably, preactivated Pak1 is resistant to IPA-3. IPA-3 also inhibits activation of related Pak isoforms regulated by autoinhibition, but not more distantly related Paks, nor >200 other kinases tested. Pak1 inhibition by IPA-3 in live cells supports a critical role for Pak in PDGF-stimulated Erk activation. These studies illustrate an alternative strategy for kinase inhibition and introduce a highly selective, cell-permeable chemical inhibitor of Pak.

Familial and perceived risk of breast cancer in relation to use of complementary medicine.

AIM: To examine the use of complementary and alternative medicine (CAM) by women with varying levels of familial and perceived risk of breast cancer with the goal of preventing breast cancer. METHODS: Cross-sectional data on CAM use were collected on 2,198 women (mean age, 63 years) personally unaffected by breast cancer in the Minnesota Breast Cancer Family Study. CAM use was compared across women at high, moderate, or average risk based on family history, as well as across categories of perceived risk of breast cancer. CAM use was also examined in relation to screening and general health behaviors, worry about breast cancer, and optimism. RESULTS: Half (49.5%) of the women reported using at least one CAM modality with the intent of preventing breast cancer. Univariate analyses indicated that greater overall CAM use was related to greater perceived risk (P = 0.018), more general health behaviors (P < 0.0001), more breast cancer screening behaviors (P = 0.0002), greater optimism (P = 0.0002), and higher educational attainment (P < 0.0001). Multivariate analysis revealed that general health behaviors (P < 0.0001), education (P = 0.0027), and optimism (P = 0.037) were significant predictors of CAM use when in the same model with perceived risk and breast cancer screening behaviors. CONCLUSIONS: Many women use CAM with the goal of preventing breast cancer. General health-promoting behaviors, education, and optimism predict CAM use. Evidence-based guidance is needed for the public and health care providers on the potential and limitations of specific CAM approaches to affect cancer risk.

The value of massage therapy in cancer care.

Massage therapy is increasingly available as a supportive therapy to patients in medical centers providing cancer treatment. This article provides an overview of the evidence base relevant to the use of massage with the intended goal of alleviating symptoms and side effects experienced by cancer patients. Collectively, the available data support the view that massage, modified appropriately, offers potential beneficial effects for cancer patients in terms of reducing anxiety and pain and other symptoms. Replication of preliminary studies with larger, more homogeneous patient samples and rigorous study designs will help to clarify which massage modalities have the most potential benefit for which patients before, during, and after specific types of cancer treatment.

Complementary and alternative therapy use in adult survivors of childhood cancer: a report from the Childhood Cancer Survivor Study.

BACKGROUND: Little information is available on the use of complementary and alternative medicine (CAM) in long-term survivors of childhood and adolescent cancer. PROCEDURE: The Childhood Cancer Survivor Study (CCSS) is a resource evaluating the long-term effects of cancer and associated therapies in 5-year survivors of childhood and adolescent cancer diagnosed between 1970 and 1986 before the age of 21 years. A survey of CAM use during the previous year was distributed in 2000-2001 and completed by 9,984 survivors and 2,474 sibling controls. RESULTS: CAM use reporting was similar in cases (39.4%) and siblings (41.1%). Compared to female siblings, female survivors were more likely to use biofeedback (odds ratio (OR) = 3.3; 95% CI = 1.0-10.8) and hypnosis/guided imagery (OR = 3.2; 95% CI = 1.6-6.8); male survivors were more likely than male siblings to use herbal remedies (OR = 1.3; 95% CI = 1.1-1.6). Factors associated with CAM use in survivors included elevated scores on the brief symptom inventory (BSI)-18 (OR = 1.6; 95% CI = 1.3-1.9), prolonged pain (OR = 1.5; 95% CI = 1.3-1.7), and having seen a physician in the past 2 years (OR = 1.6; 95% CI = 1.4-1.8). Survivors reporting low alcohol intake and excellent or good general health reported lower levels of CAM use (OR = 0.7; 95% CI = 0.7-0.8 and OR = 0.8; 95% CI = 0.7-0.9, respectively). CONCLUSIONS: Survivors have a similar reported use of CAM compared to a sibling cohort. However, our data suggest that survivors turn to CAM for specific symptoms related to previous diagnosis and treatment. Future research is needed to determine whether CAM use reflects unmet health needs in this population.

Coping predictors of children's laboratory-induced pain tolerance, intensity, and unpleasantness.

UNLABELLED: This study examined coping predictors of laboratory-induced pain tolerance, intensity, and unpleasantness among 244 healthy children and adolescents (50.8% female; mean age, 12.73 +/- 2.98 years; range, 8-18 years). Participants were exposed to separate 4-trial blocks of pressure and thermal (heat) pain stimuli, as well as 1 trial of cold pain stimuli. Strategies for coping with pain were measured using the Pain Coping Questionnaire (PCQ). Linear regression analyses were conducted to examine the associations between the 8 PCQ subscales and pain responses (pain tolerance, intensity, and unpleasantness) to all 3 pain tasks, controlling for age and sex. We found that internalizing/catastrophizing predicted higher pain intensity across the 3 pain tasks and higher cold pain unpleasantness; seeking emotional support predicted lower pressure pain tolerance; positive self-statements predicted lower pressure pain intensity and lower cold pain intensity and unpleasantness; and behavioral distraction predicted higher pressure pain tolerance and lower heat pain unpleasantness. These results suggest that in healthy children, internalizing/catastrophizing, and seeking emotional support may be conceptualized as pain-prone coping strategies, and positive self-statements and behavioral distraction as pain-resistant coping strategies within the context of laboratory pain. PERSPECTIVE: These results support investigation of interventions with children that aim to reduce acute pain responses by modifying coping to reduce seeking of emotional support and catastrophizing and enhance the use of positive self statements and behavioral distraction.

Self-care behaviors associated with myofascial temporomandibular disorder pain.

AIMS: To document the frequency of self-care in a clinical sample of patients with myofascial temporomandibular disorder (TMD) pain; report the perceived relief and control of pain for each of the self-care behaviors; and to test for associations between the frequency and efficacy of each self-care behavior and pain, depression and sleep quality, as assessed during a clinical visit, and to determine whether the frequency was associated with changes in pain intensity, depression, and sleep quality 30 days later. METHODS: The sample consisted of 99 female and 27 male myofascial TMD pain patients who were participants in a multidisciplinary facial pain evaluation program. The subjects participated in a structured interview during a clinical visit and a follow-up telephone interview 30 days later. The interviews included questions about self-care, including resting, relaxation techniques, massage, hot and/or cold packs, home remedies, stretching or exercise, herbal remedies, and the use of vitamins or nutritional supplements for pain. RESULTS: The passive self-care behaviors, such as resting when experiencing pain (66%) and relaxation techniques (62%), were the most commonly used. Patients reported that hot or cold packs (5.3, 0-to-10 scale) and massage (4.7) provided the greatest relief from pain, whereas resting (4.9), relaxation (4.8), and massage (4.8) resulted in the greatest ability to control pain. The most striking finding was that initial levels of pain or change in pain were not consistently associated with self-care use; however, psychosocial outcomes of depression and sleep quality were associated with self-care frequency and reported efficacy and improved in relation to patient-reported self-care frequency. CONCLUSION: Since people with chronic myofascial TMD pain engage in a range of pain self-care strategies, clinicians need to discuss self-care with patients regularly.

Complementary and alternative medicine for persistent facial pain.

This article discusses complementary and alternative medicine (CAM), reviews literature on the prevalence of use of CAM by the general adult population in the United States and by patients with persistent facial pain, and summarizes published, peer-reviewed reports of clinical trials assessing the effects of CAM therapies for persistent facial pain. Results indicate that many patients use CAM for musculoskeletal pain, including persistent facial pain. Preliminary work on selected complementary therapies such as biofeedback, relaxation, and acupuncture seems promising; however, there are more unanswered than answered questions about cost-effectiveness, efficacy and mechanisms of action of CAM for persistent facial pain.

p120-catenin regulates VE-cadherin endocytosis and degradation induced by the Kaposi sarcoma-associated ubiquitin ligase K5.

Vascular endothelial (VE)-cadherin undergoes constitutive internalization driven by a unique endocytic motif that also serves as a p120-catenin (p120) binding site. p120 binding masks the motif, stabilizing the cadherin at cell junctions. This mechanism allows constitutive VE-cadherin endocytosis and recycling to contribute to adherens junction dynamics without resulting in junction disassembly. Here we identify an additional motif that drives VE-cadherin endocytosis and pathological junction disassembly associated with the endothelial-derived tumor Kaposi sarcoma. Human herpesvirus 8, which causes Kaposi sarcoma, expresses the MARCH family ubiquitin ligase K5. We report that K5 targets two membrane-proximal VE-cadherin lysine residues for ubiquitination, driving endocytosis and down-regulation of the cadherin. K5-induced VE-cadherin endocytosis does not require the constitutive endocytic motif. However, K5-induced VE-cadherin endocytosis is associated with displacement of p120 from the cadherin, and p120 protects VE-cadherin from K5. Thus multiple context-dependent signals drive VE-cadherin endocytosis, but p120 binding to the cadherin juxtamembrane domain acts as a master regulator guarding cadherin stability.

Parent and child anxiety sensitivity: relationship to children's experimental pain responsivity.

UNLABELLED: Anxiety sensitivity (AS) or fear of anxiety sensations has been linked to childhood learning history for somatic symptoms, suggesting that parental AS may impact children's responses to pain. Using structural equation modeling, we tested a conceptual model in which parent AS predicted child AS, which in turn predicted a hypothesized latent construct consisting of children's pain intensity ratings for 3 laboratory pain tasks (cold pressor, thermal heat, and pressure). This conceptual model was tested in 211 nonclinical parent-child pairs (104 girls, 107 boys; mean age 12.4 years; 178 mothers, 33 fathers). Our model was supported in girls only, indicating that the sex of the child moderated the hypothesized relationships. Thus, parent AS was related to child laboratory pain intensity via its contribution to child AS in girls but not in boys. In girls, 42% of the effect of parent AS on laboratory pain intensity was explained via child AS. In boys, there was no clear link between parent AS and child AS, although child AS was predictive of experimental pain intensity across sex. Our results are consistent with the notion that parent AS may operate via healthy girls' own fear of anxiety symptoms to influence their responses to laboratory pain stimuli. PERSPECTIVE: The present study highlights sex differences in the links among parent and child anxiety sensitivity (fear of anxiety sensations) and children's experimental pain responses. Among girls, childhood learning history related to somatic symptoms may be a particularly salient factor in the development of anxiety sensitivity and pain responsivity.