Spatiotemporal tracking of cells in tissue‐engineered cardiac organoids

Cardiac tissue engineering aims to create myocardial patches for repair of defective or damaged native heart muscle. The inclusion of non‐myocytes in engineered cardiac tissues has been shown to improve the properties of cardiac tissue compared to tissues engineered from enriched populations of myocytes alone. While attempts have been made to mix non‐myocytes (fibroblasts, endothelial cells) with cardiomyocytes, very little is understood about how the tissue properties are affected by varying the respective ratios of the three cell types and how these cells assemble into functional tissues with time. The goal of this study was to investigate the effects of modulating the ratios of the three cell types and to spatially and temporally track cardiac tri‐cultures of cells. Primary neonatal cardiac fibroblasts and D4T endothelial cells were incubated in 5 µM CellTracker^? green dye and CellTracker^? red dye, respectively, while neonatal cardiomyocytes were labelled with 20 µg/mL DAPI. The non‐myocytes were seeded either sequentially (pre‐culture) or simultaneously (tri‐culture) in Matrigel‐coated microchannels and allowed to form organoids, as in our previous studies. We also varied the seeding percentage of cardiomyocytes while keeping the total cell number constant in an attempt to improve the functional properties of the organoids. Organoids were imaged on days 1 and 4. Endothelial cells were seen to aggregate into clusters when simultaneously tri‐cultured with myocytes and fibroblasts, while pre‐cultures contained elongated cells. Functional properties of organoids were improved by increasing the seeding percentage of enriched cardiomyocytes from 40% to 80%. Copyright © 2009 John Wiley & Sons, Ltd.     

Biochemical and Hemostatic Mechanism of A Novel Thrombin-Like Enzyme

Thrombin-like enzyme (TLE) plays a significant role in vessel injury hemostasis. A novel snake venom TLE (Agacutin) was purified from Agkistrodon Acutus snake venom. Structural analysis indicated that Agacutin is a heterodimer that has a MW of 29,402 Da, a pI value of 5.39, and optimum activity at 35 °C and pH 7.5. The N-terminal 15 amino acid sequences of Agacutin are DSSGWSSYEGHEYYV (small subunit) and DCSSGWSSYEEHQYY (large subunit). In vitro studies indicated that the coagulation activity of Agacutin was activated by Ca⁺² or inhibited by phenylmethanesulfonyl fluoride, but not influenced by heparin or hirudin. The arginine esterase activity and fibrinogen hydrolysis result showed that Agacutin only cleaves α-subunit and releases fibrinopeptide A. In vivo studies indicated that Agacutin iv (0.01-0.05 U/kg) shortened 30.2-49% of the rabbit blood clotting time, or ip (0.5-2.0 U/kg) shortened 29.7-73.1% of the mouse tail bleeding time. Agacutin does not influence APTT, platelet or euglobulin clotting time, and activate Factor II or XIII. It converts fibrinogen into the soluble fibrin that accelerates hemostasis at wound.     

Elucidating the molecular physiopathology of acute respiratory distress syndrome in severe acute respiratory syndrome patients

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury. It is a response to various diseases of variable etiology, including SARS-CoV infection. To date, a comprehensive study of the genomic physiopathology of ARDS (and SARS) is lacking, primarily due to the difficulty of finding suitable materials to study the disease process at a tissue level (instead of blood, sputa or swaps). Hereby we attempt to provide such study by analyzing autopsy lung samples from patient who died of SARS and showed different degrees of severity of the pulmonary involvement. We performed real-time quantitative PCR analysis of 107 genes with functional roles in inflammation, coagulation, fibrosis and apoptosis; some key genes were confirmed at a protein expression level by immunohistochemistry and correlated to the degree of morphological severity present in the individual samples analyzed. Significant expression levels were identified for ANPEP (a receptor for CoV), as well as inhibition of the STAT1 pathway, IFNs production and CXCL10 (a T-cell recruiter). Other genes unassociated to date with ARDS/SARS include C1Qb, C5R1, CASP3, CASP9, CD14, CD68, FGF7, HLA-DRA, IGF1, IRF3, MALAT-1, MSR1, NFIL3, SLPI, USP33, CLC, GBP1 and TAC1. As a result, we proposed to therapeutically target some of these genes with compounds such as ANPEP inhibitors, SLPI and dexamethasone. Ultimately, this study may serve as a model for future, tissue-based analyses of fibroinflammatory conditions affecting the lung.     

Fetal erythropoiesis in steel mutant mice. III. Defect in differentiation from BFU-E to CFU-E during early development

Erythroid progenitor cells in +/+ and Sl/Sld fetal livers manifested as burst-forming units-erythroid (BFU-E) and colony-forming units- erythroid (CFU-E) were assayed in vitro during early development. The proportion of BFU-E was higher as mutant than in normal fetal livers. On the other hand, the proportion of CFU-E was less in the mutant than in the normal. These results suggest that the defect in Sl/Sld fetal hepatic erythropoiesis is expressed at the steps of differentiation that effect the transition from BFU-E to CFU-E.     

Caregiver- and Child-Reported Anxiety Using an Autism-Specific Measure: Measurement Properties and Correlates of the Anxiety Scale for Children with Autism Spectrum Disorder (ASC-ASD) in Verbal Young People with ASD

Identifying and measuring anxiety in young people on the autism spectrum can be challenging. The present study investigated the use of the Anxiety Scale for Children with Autism Spectrum Disorder (ASC-ASD), a self- and caregiver-rated screening tool in a Singaporean sample of ninety-one verbal autistic youths and their caregivers. Internal consistency ranged from satisfactory to desirable (α?=?.74–.92). Convergent validity with medium-large effect size was established using a structured diagnostic interview, the Mini-International Neuropsychiatric Interview for Children and Adolescents (MINI-KID). ASC-ASD scores were positively associated with autistic symptoms and response patterns indicated strong endorsement of autism-specific items. The findings are discussed in relation to existing literature on assessment of anxiety in ASD and in light of the study’s strengths and limitations.

     

Influences of lobar gray matter and white matter lesion load on cognition and mood

Depressed mood is a frequent co-morbidity of dementia suggesting that they might share a common neuropathological substrate. Gray matter (GM) atrophy and white matter lesions (WML) have been described in both conditions. Our aims were to determine the relationship of GM and WML with cognition and depressed mood in the same population. Structural brain images were obtained from 42 controls, 20 Alzheimer's disease (AD) patients and 32 subjects with cognitive impairment/dementia due to subcortical cerebrovascular disease (vascCIND/IVD). Images were segmented to obtain lobar GM, white matter and WML volumes. Lobar WML had a negative effect on GM in all lobes in controls, on frontal, parietal and occipital GM in AD and on frontal GM in vascCIND/IVD. Frontal, temporal and hippocampal GM were associated with cognitive functions and frontal WML load with depressed mood. Cognitive function is associated with GM atrophy and depressed mood is associated with frontal WML. This indicates that although both often occur together, depressed mood and cognitive impairment have different pathological correlates.     

Magnetic resonance imaging of the entorhinal cortex and hippocampus in mild cognitive impairment and Alzheimer's disease

OBJECTIVES: To explore volume changes of the entorhinal cortex (ERC) and hippocampus in mild cognitive impairment (MCI) and Alzheimer's disease (AD) compared with normal cognition (NC); to determine the powers of the ERC and the hippocampus for discrimination between these groups. METHODS: This study included 40 subjects with NC, 36 patients with MCI, and 29 patients with AD. Volumes of the ERC and hippocampus were manually measured based on coronal T1 weighted MR images. Global cerebral changes were assessed using semiautomatic image segmentation. RESULTS: Both ERC and hippocampal volumes were reduced in MCI (ERC 13%, hippocampus 11%, p<0.05) and AD (ERC 39%, hippocampus 27%, p<0.01) compared with NC. Furthermore, AD showed greater volume losses in the ERC than in the hippocampus (p<0.01). In addition, AD and MCI also had cortical grey matter loss (p< 0.01) and ventricular enlargement (p<0.01) when compared with NC. There was a significant correlation between ERC and hippocampal volumes in MCI and AD (both p<0.001), but not in NC. Using ERC and hippocampus together improved discrimination between AD and CN but did not improve discrimination between MCI and NC. The ERC was better than the hippocampus for distinguishing MCI from AD. In addition, loss of cortical grey matter significantly contributed to the hippocampus for discriminating MCI and AD from NC. CONCLUSIONS: Volume reductions in the ERC and hippocampus may be early signs of AD pathology that can be measured using MRI.     

Antiproliferative Activity Against MCF‐7 Breast Cancer Cells by Diamino‐Triazaspirodiene Antifolates

Two triazaspirodienes, having similar phenoxy propyloxy side chain, were identified as potent mammalian dihydrofolate reductase inhibitors; one having a 6,5‐spiro bicyclic ring system (IC₅₀ = 2.3 nm ) and the other a 6,6‐spiro bicyclic system (IC₅₀ = 6.9 nm ). They also showed more than 50% antiproliferative activity against the MCF‐7 breast cancer cells at 20 μm . This study demonstrated the potential lead of the diamino‐triazaspirodienes in anticancer chemotherapeutical agents’ discovery.     

手把手教初学者学习医学影像学论文写作

青年学者常常在完成资料收集和分析之后对获得的结果充满了激情。然而,在开始写作论文时,这种热情常常锐减。事实也如此,国家级学术会议的论文数远高于最终发表的医学文献数。优秀的研究成果不能发表的原因2大多在于写作新手在开始写作时对写作的认识混乱和畏缩。一般产生畏缩的原因有2个:要么是研究者不知从何着手,要么是不知如何组织文章结构。不过,大部分放射学论文的写作均有规律可寻,在很大程度上是程式化的。本文试图介绍一种可应用于典型放射学论文的逐段写作法。如果初学者能够完成按照本文教授的18段写作,其论文将具有合理的结构,…