1,354 research outputs found

    3D Engineered Peripheral Nerve: Towards A New Era of Patient-Specific Nerve Repair Solutions

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    Reconstruction of peripheral nerve injuries (PNIs) with substance loss remains challenging because of limited treatment solutions and unsatisfactory patient outcomes. Currently, nerve autografting is the first-line management choice for bridging critical-sized nerve defects. The procedure, however, is often complicated by donor site morbidity and paucity of nerve tissue, raising a quest for better alternatives. The application of other treatment surrogates, such as nerve guides remains questionable, and inefficient in irreducible nerve gaps. More importantly, these strategies lack customization for personalized patient therapy, which is a significant drawback of these nerve repair options. This negatively impacts the fascicle-to-fascicle regeneration process, critical to restoring the physiological axonal pathway of the disrupted nerve. Recently, the use of additive manufacturing (AM) technologies has offered major advancements to the bioengineering solutions for PNI therapy. These techniques aim to reinstate the native nerve fascicle pathway using biomimetic approaches, thereby augmenting end-organ innervation. AM-based approaches, such as 3D bioprinting, are capable of biofabricating 3D engineered nerve graft scaffolds in a patient-specific manner with high precision. Moreover, realistic in vitro models of peripheral nerve tissues that represent the physiologically and functionally relevant environment of human organs could also be developed. However, the technology is still nascent and faces major translational hurdles. In this review, we spotlighted the clinical burden of PNIs and most up-to-date treatment to address nerve gaps. Next, a summarized illustration of the nerve ultrastructure that guides research solutions is discussed. This is followed by a contrast of the existing bioengineering strategies used to repair peripheral nerve discontinuities. In addition, we elaborated on the most recent advances in 3D printing (3DP) and biofabrication applications in peripheral nerve modeling and engineering. Finally, the major challenges that limit the evolution of the field along with their possible solutions are also critically analyzed

    Correlation between maternal serum biochemical markers with karyotyping for prenatal screening of foetal chromosomal abnormalities

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    Background: Prenatal screening for chromosomal abnormalities can be done by biochemical screening tests like dual marker test (DMT), triple marker test (TMT) and quadruple marker test (QMT). It is important to identify ideal screening test among them which best correlates with result of karyotyping which is confirmatory test of foetal chromosomal abnormalities. This helps to decrease need for invasive prenatal tests for foetal karyotyping. This study aims to evaluate sensitivity, specificity, diagnostic accuracy and correlation of DMT, TMT, and QMT with results of karyotyping.Methods: Retrospective observational study was conducted in tertiary care maternity hospital over one year- 1st January 2015 to 31st December 2015. Women with singleton pregnancy undergoing DMT, TMT or QMT were included.Results: Of the 529 women screened by biochemical marker tests, 462 (87.33%) were screen negative and 67 (12.66%) women were screen positive. In 56 women, it was false positive (83.58%) and in 11 women true positive (16.41%). In 461 women the test results were true negative (99.78%), but in one case, result was false negative (0.21%).  3/11 (27.27%)women with foetal chromosomal abnormalities were primigravidae. 4/11 (36.36%)women were below 35 years. DMT and QMT had higher sensitivity (both 100%) and specificity (90.00% and 93.18% respectively) than TMT (sensitivity 80% and specificity 82.61%). Positive likelihood ratio (LR+) was 1.00 in DMT. Diagnostic odds ratio was highest with DMT (DOR=115.11) and best correlated with karyotyping results (coefficient of correlation 0.4).Conclusions: Universal screening of antenatal women, irrespective of their age and parity is suggested. DMT has highest diagnostic value and best correlation with the results of karyotyping. Hence the dual marker test can be considered to be better test for screening for aneuploidy

    Relating field-induced shift in transition temperature to the kinetics of coexisting phases in magnetic shape memory alloys

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    In a magnetic shape memory alloy system, we vary composition following phenomenological arguments to tune macroscopic properties. We achieve significantly higher shift in austenite to martensitic phase transition temperature with magnetic field. This enhancement is accompanied by significant broadening of the transition and by field-induced arrest of kinetics, both of which are related to the dynamics of the coexisting phases. This reveals hitherto unknown interrelationship between different length-scales. This may serve as an effective route for comprehensive understanding of similar multicomponent systems which show considerable variation in physical properties by minor change in microscopic parameters.Comment: The "Cooling and Heating in Unequal Fields" (CHUF) protocol originated by us is used to prove the existence of glass-like kinetically arrested but long-range structurally and magnetically ordered state and also to identify the ground (low temperature equilibrium) stat

    Improving maternal confidence in neonatal care through a checklist intervention

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    Previous qualitative studies suggest a lack of maternal confidence in care of their newborn child upon discharge into the community. This observation was supported by discussion with healthcare professionals and mothers at University College London Hospital (UCLH), highlighting specific areas of concern, in particular identifying and managing common neonatal presentations. The aim of this study was to design and introduce a checklist, addressing concerns, to increase maternal confidence in care of their newborn child. Based on market research, an 8-question checklist was designed, assessing maternal confidence in: feeding, jaundice, nappy care, rashes and dry skin, umbilical cord care, choking, bowel movements, and vomiting. Mothers were assessed as per the checklist, and received a score representative of their confidence in neonatal care. Mothers were followed up with a telephone call, and were assessed after a 7-day-period. Checklist scores before as compared to after the follow-up period were analysed. This process was repeated for three study cycles, with the placement of information posters on the ward prior to the second study cycle, and the stapling of the checklist to the mother's personal child health record (PCHR) prior to the third study cycle. A total of 99 mothers on the Maternity Care Unit at UCLH were enrolled in the study, and 92 were contactable after a 7-day period. During all study cycles, a significant increase in median checklist score was observed after, as compared to before, the 7-day follow up period (p < 0.001). The median difference in checklist score from baseline was greatest for the third cycle. These results suggest that introduction of a simple checklist can be successfully utilised to improve confidence of mothers in being able to care for their newborn child. Further investigation is indicated, but this intervention has the potential for routine application in postnatal care

    History-dependent nucleation and growth of the martensitic phase in the magnetic shape memory alloy Ni<SUB>45</SUB>Co<SUB>5</SUB>Mn<SUB>38</SUB>Sn<SUB>12</SUB>

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    We study through the time evolution of magnetization the low-temperature (T) dynamics of the metastable coexisting phases created by traversing different paths in magnetic field H and T space in a shape memory alloy system, Ni45Co5Mn38Sn12. It is shown that these coexisting phases consisting of a fraction of kinetically arrested austenite phase and a remaining fraction of low-T equilibrium martensitic phase undergo a slow relaxation to low magnetization (martensitic) state but with very different thermomagnetic history-dependent rates at the same T and H. We discovered that, when the nucleation of the martensitic phase is initiated at much lower T through the de-arrest of the glasslike arrested state contrasted with the respective first-order transformation (through supercooling at much higher T), the long-time relaxation rate scales with the nonequilibrium phase fraction but has a very weak dependence on T. This is explained on the basis of the H-T path dependent size of the critical radii of the nuclei and the subsequent growth of the equilibrium phase through the motion of the interface

    Lobular carcinoma in situ of the breast is not caused by constitutional mutations in the E-cadherin gene

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    Lobular carcinoma in situ (LCIS) is an unusual histological pattern of non-invasive neoplastic disease of the breast occurring predominantly in women aged between 40 and 50 years. LCIS is frequently multicentric and bilateral, and there is evidence that it is associated with an elevated familial risk of breast cancer. Although women with LCIS suffer an increased risk of invasive breast disease, this risk is moderate suggesting that LCIS may result from mutation of a gene or genes conferring a high risk of LCIS, but a lower risk of invasive breast cancer. The high frequency of somatic mutations in E-cadherin in LCIS, coupled with recent reports that germline mutations in this gene can predispose to diffuse gastric cancer, raised the possibility that constitutional E-cadherin mutations may confer susceptibility to LCIS. In order to explore this possibility we have examined a series of 65 LCIS patients for germline E-cadherin mutations. Four polymorphisms were detected but no pathogenic mutations were identified. The results indicate that E-cadherin is unlikely to act as a susceptibility gene for LCIS. © 2000 Cancer Research Campaig
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