Effects of External Physical Assistive Devices on Gait.

Assistive devices (ADs) are often used by rehabilitation professionals to help individuals walk independently. When using ADs, individuals show observable changes in their walking pattern. However, little research exists objectively documenting the acute, real-time changes in gait that occur despite the significant influence these devices exert on an individual’s movement. Understanding the acute changes in movement that occur with use of an AD is a very important component in the decision-making process for rehabilitation professionals who recommend and, often, provide ADs to patients in the hospital or clinic to foster patient compliance and thus, safety. This series of research studies examining external AD use are the first to quantitatively and qualitatively report both overt and underlying acute changes in gait for two unique populations: children with myelomeningocele (MMC) and typically developing (TD) infants learning to cruise. Overall, our results showed that use of ADs caused changes in gait patterns of children with MMC and TD infants. For children with MMC walking with rigid ADs compared to independently, changes were found in not only basic gait characteristics, but muscle activation patterns, and energy consumption. However, for TD infants wearing a flexible AD around the hips and pelvis while cruising, gait adaptations were more subtle as evidenced by minimal to no changes in segmental angle trajectories and classic gait parameters. Despite the lack of change in overt gait parameters for infants while cruising in the flexible AD, more apparent adaptations were shown in dynamic representations of cruising behavior (e.g., shifts in state space location for phase plane portrait plots). The studies presented show that these two unique populations, children with MMC and TD infants, have the capacity and flexibility to acutely adapt their motor control strategies, segment coordination, and movement patterns to application of external manipulations. What we don’t know is if, over the long-term, these adaptations will result in decreased or increased dependency on ADs. Therefore, further research is warranted to investigate impact of these devices on both overt movement behaviors and underlying control mechanisms before we can determine if use of ADs help or hinder functional mobility.PHDKinesiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/97918/1/jksansom_1.pd

Approximate Entropy Values Demonstrate Impaired Neuromotor Control of Spontaneous Leg Activity in Infants with Myelomeningocele

Purpose: One obstacle to providing early intervention to infants with myelomeningocele (MMC) is the challenge of quantifying impaired neuromotor control of movements early in life. Methods: We used the nonlinear analysis tool Approximate Entropy (ApEn) to analyze periodicity and complexity of supine spontaneous lower extremity movements of infants with MMC and typical development (TD) at 1, 3, 6, and 9 months of age. Results: Movements of infants with MMC were more regular and repeatable (lower ApEn values) than movements of infants with TD, indicating less adaptive and flexible movement patterns. For both groups ApEn values decreased with age, and the movements of infants with MMC were less complex than movements of infants with TD. Further, for infants with MMC, lesion level and age of walking onset correlated negatively with ApEn values. Conclusions: Our study begins to demonstrate the feasibility of ApEn to identify impaired neuromotor control in infants with MMC

Forearm EMG During Rock Climbing Differs from EMG During Handgrip Dynamometry

Grip force, as measured via handgrip dynamometry, is often given importance in the study of rock climbing performance. Whether handgrip dynamometry produces a degree of muscle activation comparable to actual climbing has not been reported. Furthermore, the degree and variability of muscle activation for various configurations during climbing are unknown. The purpose of this study was to record forearm EMG responses for six hand configurations during climbing and to compare these responses to a maximum handgrip test. Five experienced climbers signed informed consent to participate in the study. Subjects performed four moves up (UP) and down (DN) on an overhanging 45-deg. climbing wall with each of six hand configurations: crimp (C), pinch (P), three 2-finger combinations (2F1, 2F2, 2F3) and an open-hand grip (O). Forearm EMG was recorded via surface electrodes. Data were recorded for the second UP and second DN moves. Prior to climbing, maximum handgrip force (HG) and simultaneous EMG were obtained. Mean HG force was 526.6±33.3 N. Times to complete the climbing movements with each hand configuration varied between 3.1±0.5 and 4.8±0.9 sec, however no significant differences were found. All peak EMG’s during climbing were higher than HG EMG (p\u3c.05). Mean EMG amplitudes for UP, expressed as percentages of HG EMG, were 198±55, 169±22, 222±72, 181±39, 126±32, and 143±47% for C, P, 2F1, 2F2, 2F3, and O respectively. Significant differences were found for O versus 2F1 and for 2F3 versus 2F1 and C (p\u3c.05). All EMG amplitudes were lower for DN than UP (p\u3c.05). Since all climbing EMGs exceeded HG EMG, it was concluded that handgrip dynamometry lacks specificity to actual rock climbing

AKT regulates NPM dependent ARF localization and p53mut stability in tumors

Nucleophosmin (NPM) is known to regulate ARF subcellular localization and MDM2 activity in response to oncogenic stress, though the precise mechanism has remained elusive. Here we describe how NPM and ARF associate in the nucleoplasm to form a MDM2 inhibitory complex. We find that oligomerization of NPM drives nucleolar accumulation of ARF. Moreover, the formation of NPM and ARF oligomers antagonizes MDM2 association with the inhibitory complex, leading to activation of MDM2 E3-ligase activity and targeting of p53. We find that AKT phosphorylation of NPM-Ser48 prevents oligomerization that results in nucleoplasmic localization of ARF, constitutive MDM2 inhibition and stabilization of p53. We also show that ARF promotes p53 mutant stability in tumors and suppresses p73 mediated p21 expression and senescence. We demonstrate that AKT and PI3K inhibitors may be effective in treatment of therapeutically resistant tumors with elevated AKT and carrying gain of function mutations in p53. Our results show that the clinical candidate AKT inhibitor MK-2206 promotes ARF nucleolar localization, reduced p53(mut) stability and increased sensitivity to ionizing radiation in a xenograft model of pancreatic cancer. Analysis of human tumors indicates that phospho-S48-NPM may be a useful biomarker for monitoring AKT activity and in vivo efficacy of AKT inhibitor treatment. Critically, we propose that combination therapy involving PI3K-AKT inhibitors would benefit from a patient stratification rationale based on ARF and p53(mut) status

Expression of KOC, S100P, mesothelin and MUC1 in pancreatico-biliary adenocarcinomas: development and utility of a potential diagnostic immunohistochemistry panel

<b>Background</b> Pancreatico-biliary adenocarcinomas (PBA) have a poor prognosis. Diagnosis is usually achieved by imaging and/or endoscopy with confirmatory cytology. Cytological interpretation can be difficult especially in the setting of chronic pancreatitis/cholangitis. Immunohistochemistry (IHC) biomarkers could act as an adjunct to cytology to improve the diagnosis. Thus, we performed a meta-analysis and selected KOC, S100P, mesothelin and MUC1 for further validation in PBA resection specimens.<p></p> <b>Methods</b> Tissue microarrays containing tumour and normal cores in a ratio of 3:2, from 99 surgically resected PBA patients, were used for IHC. IHC was performed on an automated platform using antibodies against KOC, S100P, mesothelin and MUC1. Tissue cores were scored for staining intensity and proportion of tissue stained using a Histoscore method (range, 0–300). Sensitivity and specificity for individual biomarkers, as well as biomarker panels, were determined with different cut-offs for positivity and compared by summary receiver operating characteristic (ROC) curve.<p></p> <b>Results</b> The expression of all four biomarkers was high in PBA versus normal ducts, with a mean Histoscore of 150 vs. 0.4 for KOC, 165 vs. 0.3 for S100P, 115 vs. 0.5 for mesothelin and 200 vs. 14 for MUC1 (p < .0001 for all comparisons). Five cut-offs were carefully chosen for sensitivity/specificity analysis. Four of these cut-offs, namely 5%, 10% or 20% positive cells and Histoscore 20 were identified using ROC curve analysis and the fifth cut-off was moderate-strong staining intensity. Using 20% positive cells as a cut-off achieved higher sensitivity/specificity values: KOC 84%/100%; S100P 83%/100%; mesothelin 88%/92%; and MUC1 89%/63%. Analysis of a panel of KOC, S100P and mesothelin achieved 100% sensitivity and 99% specificity if at least 2 biomarkers were positive for 10% cut-off; and 100% sensitivity and specificity for 20% cut-off.<p></p> <b>Conclusion</b> A biomarker panel of KOC, S100P and mesothelin with at least 2 biomarkers positive was found to be an optimum panel with both 10% and 20% cut-offs in resection specimens from patients with PBA.<p></p&gt

mTORC1 activity is essential for erythropoiesis and B cell lineage commitment

Mechanistic target of rapamycin (mTOR) is a serine/threonine protein kinase that mediates phosphoinositide-3-kinase (PI3K)/AKT signalling. This pathway is involved in a plethora of cellular functions including protein and lipid synthesis, cell migration, cell proliferation and apoptosis. In this study, we proposed to delineate the role of mTORC1 in haemopoietic lineage commitment using knock out (KO) mouse and cell line models. Mx1-cre and Vav-cre expression systems were used to specifically target Raptorfl/fl (mTORC1), either in all tissues upon poly(I:C) inoculation, or specifically in haemopoietic stem cells, respectively. Assessment of the role of mTORC1 during the early stages of development in Vav-cre+Raptorfl/fl mice, revealed that these mice do not survive post birth due to aberrations in erythropoiesis resulting from an arrest in development at the megakaryocyte-erythrocyte progenitor stage. Furthermore, Raptor-deficient mice exhibited a block in B cell lineage commitment. The essential role of Raptor (mTORC1) in erythrocyte and B lineage commitment was confirmed in adult Mx1-cre+Raptorfl/fl mice upon cre-recombinase induction. These studies were supported by results showing that the expression of key lineage commitment regulators, GATA1, GATA2 and PAX5 were dysregulated in the absence of mTORC1-mediated signals. The regulatory role of mTOR during erythropoiesis was confirmed in vitro by demonstrating a reduction of K562 cell differentiation towards RBCs in the presence of established mTOR inhibitors. While mTORC1 plays a fundamental role in promoting RBC development, we showed that mTORC2 has an opposing role, as Rictor-deficient progenitor cells exhibited an elevation in RBC colony formation ex vivo. Collectively, our data demonstrate a critical role played by mTORC1 in regulating the haemopoietic cell lineage commitment

Confirming the Environmental Concerns of Community Members Utilizing Participatory-Based Research in the Houston Neighborhood of Manchester

In the last few decades, there has been an increase in community-based participatory research being conducted within the United States. Recent research has demonstrated that working with local community organizations, interest groups, and individuals can assist in the creation of, and sustainability in, health initiatives, adoption of emergency protocols, and potentially improve health outcomes for at-risk populations. However little research has assessed if communal concerns over environmental contaminants would be confirmed through environmental research. This cross-sectional study collected survey data and performed surface water analysis for heavy metals in a small neighborhood in Houston, TX, which is characterized by industrial sites, unimproved infrastructure, nuisance flooding, and poor air quality. Surveys were completed with 109 residents of the Manchester neighborhood. Water samples were taken from thirty zones within the neighborhood and assessed for arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), selenium (Se), silver (Ag), and mercury (Hg). Survey results showed that the vast majority of all respondents were concerned over proximity to industry and waste facilities, as well as exposure to standing surface water. Barium was discovered in every sample and many of the zones showed alarming levels of certain metals. For example, one zone, two blocks from a public park, showed levels of arsenic at 180 (μg/L), barium at 3296 (μg/L), chromium at 363 (μg/L), lead at 1448 (μg/L), and mercury at 10 (μg/L). These findings support the hypothesis that neighborhood members are aware of the issues affecting their community and can offer researchers valuable assistance in every stage of study design and execution

RelA regulates CXCL1/CXCR2-dependent oncogene-induced senescence in murine Kras-driven pancreatic carcinogenesis

Tumor suppression that is mediated by oncogene-induced senescence (OIS) is considered to function as a safeguard during development of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms that regulate OIS in PDAC are poorly understood. Here, we have determined that nuclear RelA reinforces OIS to inhibit carcinogenesis in the Kras mouse model of PDAC. Inactivation of RelA accelerated pancreatic lesion formation in Kras mice by abrogating the senescence-associated secretory phenotype (SASP) gene transcription signature. Using genetic and pharmacological tools, we determined that RelA activation promotes OIS via elevation of the SASP factor CXCL1 (also known as KC), which activates CXCR2, during pancreatic carcinogenesis. In Kras mice, pancreas-specific inactivation of CXCR2 prevented OIS and was correlated with increased tumor proliferation and decreased survival. Moreover, reductions in CXCR2 levels were associated with advanced neoplastic lesions in tissue from human pancreatic specimens. Genetically disabling OIS in Kras mice caused RelA to promote tumor proliferation, suggesting a dual role for RelA signaling in pancreatic carcinogenesis. Taken together, our data suggest a pivotal role for RelA in regulating OIS in preneoplastic lesions and implicate the RelA/CXCL1/CXCR2 axis as an essential mechanism of tumor surveillance in PDAC

The senescence-associated secretory phenotype induces cellular plasticity and tissue regeneration

Senescence is a form of cell cycle arrest induced by stress such as DNA damage and oncogenes. However, while arrested, senescent cells secrete a variety of proteins collectively known as the senescence-associated secretory phenotype (SASP), which can reinforce the arrest and induce senescence in a paracrine manner. However, the SASP has also been shown to favor embryonic development, wound healing, and even tumor growth, suggesting more complex physiological roles than currently understood. Here we uncover timely new functions of the SASP in promoting a proregenerative response through the induction of cell plasticity and stemness. We show that primary mouse keratinocytes transiently exposed to the SASP exhibit increased expression of stem cell markers and regenerative capacity in vivo. However, prolonged exposure to the SASP causes a subsequent cell-intrinsic senescence arrest to counter the continued regenerative stimuli. Finally, by inducing senescence in single cells in vivo in the liver, we demonstrate that this activates tissue-specific expression of stem cell markers. Together, this work uncovers a primary and beneficial role for the SASP in promoting cell plasticity and tissue regeneration and introduces the concept that transient therapeutic delivery of senescent cells could be harnessed to drive tissue regeneration

mTORC2 signaling drives the development and progression of pancreatic cancer

mTOR signaling controls several critical cellular functions and is deregulated in many cancers, including pancreatic cancer. To date, most efforts have focused on inhibiting the mTORC1 complex. However, clinical trials of mTORC1 inhibitors in pancreatic cancer have failed, raising questions about this therapeutic approach. We employed a genetic approach to delete the obligate mTORC2 subunit Rictor and identified the critical times during which tumorigenesis requires mTORC2 signaling. Rictor deletion resulted in profoundly delayed tumorigenesis. Whereas previous studies showed most pancreatic tumors were insensitive to rapamycin, treatment with a dual mTORC1/2 inhibitor strongly suppressed tumorigenesis. In late-stage tumor-bearing mice, combined mTORC1/2 and PI3K inhibition significantly increased survival. Thus, targeting mTOR may be a potential therapeutic strategy in pancreatic cancer