Publications by authors named "Jirong Li"

6 Publications

  • Page 1 of 1

Evaluation of the probe burst test as a measure of strength for a biologically-engineered vascular graft.

J Mech Behav Biomed Mater 2021 07 16;119:104527. Epub 2021 Apr 16.

Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA; Department of Chemical Engineering & Materials Science, University of Minnesota, Minneapolis, MN, USA. Electronic address:

Biologically-engineered vascular grafts have the potential to provide a viable alternative to donor vessels and synthetic grafts. In congenital heart defect patients, the need is even more dire since neither has the capacity to provide somatic growth. To ensure clinically-used grafts perform to accepted standards, mechanical strength is a crucial consideration, with burst testing being considered as one key metric. While ISO 7198 standards for prosthetic vascular grafts provide multiple choices for burst testing, most studies with tissue-engineered grafts have been performed with only pressure burst testing. Here, we compare the performance of a decellularized tube of collagenous matrix grown from dermal fibroblasts, possessing circumferential fiber alignment and anisotropic tensile properties, as determined from pressure and probe burst testing. The two burst tests showed a strong correlation with each other and with tensile strength. Further, relatively weak and strong batches of grafts showed commensurate differences in pressure and probe burst values. Both probe burst and tensile strength measurements in the central and edge regions of the grafts were similar in value, consistent with homogenous collagen content and microstructure throughout the grafts as indicated by histology, in contrast to ovine femoral and carotid arteries similarly tested. Finite element analysis of the probe burst test pre-failure for a homogeneous, isotropic approximation of the matrix constitutive behavior indicated dependence of the (inferred) effective failure stress achievable on probe diameter. The results indicate a probe burst test in a sampled edge region of this biologically-engineered graft provides a representative measure of burst strength of the entire graft.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104527DOI Listing
July 2021

Pediatric tri-tube valved conduits made from fibroblast-produced extracellular matrix evaluated over 52 weeks in growing lambs.

Sci Transl Med 2021 Mar;13(585)

Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.

There is a need for replacement heart valves that can grow with children. We fabricated tubes of fibroblast-derived collagenous matrix that have been shown to regenerate and grow as a pulmonary artery replacement in lambs and implemented a design for a valved conduit consisting of three tubes sewn together. Seven lambs were implanted with tri-tube valved conduits in sequential cohorts and compared to bioprosthetic conduits. Valves implanted into the pulmonary artery of two lambs of the first cohort of four animals functioned with mild regurgitation and systolic pressure drops <10 mmHg up to 52 weeks after implantation, during which the valve diameter increased from 19 mm to a physiologically normal ~25 mm. In a second cohort, the valve design was modified to include an additional tube, creating a sleeve around the tri-tube valve to counteract faster root growth relative to the leaflets. Two valves exhibited trivial-to-mild regurgitation at 52 weeks with similar diameter increases to ~25 mm and systolic pressure drops of <5 mmHg, whereas the third valve showed similar findings until moderate regurgitation was observed at 52 weeks, correlating to hyperincrease in the valve diameter. In all explanted valves, the leaflets contained interstitial cells and an endothelium progressing from the base of the leaflets and remained thin and pliable with sparse, punctate microcalcifications. The tri-tube valves demonstrated reduced calcification and improved hemodynamic function compared to clinically used pediatric bioprosthetic valves tested in the same model. This tri-tube valved conduit has potential for long-term valve growth in children.
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http://dx.doi.org/10.1126/scitranslmed.abb7225DOI Listing
March 2021

Study on the origin traceability of Tibet highland barley (Hordeum vulgare L.) based on its nutrients and mineral elements.

Food Chem 2021 Jun 28;346:128928. Epub 2020 Dec 28.

Institute of Quality Standard & Testing Technology for Agro-Products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address:

The potential of traceability by nutrients and mineral elements in highland barley (Hordeum vulgare L.) from five cities in Tibet were investigated. The results showed that there were significant differences in nutrients and mineral elements in highland barley from different regions (P < 0.05). The original classification accuracy of linear discriminant analysis (LDA) was 78.3%, and the discrimination accuracy of training set samples based on partial least-squares discriminant analysis (PLS-DA) model was over 65%. The results of correlation analysis show that five elements (Fe, Zn, K, Mn and P) in highland barley are related to the concentration of elements in soil, while three elements (Ca, Cu and Mg) in highland barley have no obvious correlation with soil, because the special natural environment in Tibet affecting the growth of highland barley. This indicates that the origin traceability of highland barley can be achieved by measuring its nutrients and mineral elements.
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http://dx.doi.org/10.1016/j.foodchem.2020.128928DOI Listing
June 2021

Research on the Head and Neck MRA Image to Explore the Comprehensive Effect on the Recovery of Neurological Function and Rehabilitation Nursing of Patients with Acute Stroke.

World Neurosurg 2021 May 28;149:420-427. Epub 2020 Oct 28.

Department of Nursing, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha, China. Electronic address:

Background: This paper uses head and neck magnetic resonance angiography (MRA) images in the diagnosis of acute ischemic stroke (AIS), as well as the neurologic rehabilitation and the effect of rehabilitation treatment in patients with acute stroke.

Methods: We used computed tomography and head and neck MRA images to calculate the sensitivity and specificity of AIS. We measured the parameters of cerebral blood flow, cerebral blood volume, mean transit time, and peak transit time, and evaluated the degree of cerebral artery stenosis. We also analyzed the changes in these parameters in different diseased brain tissues and their correlation with the degree of cerebral artery stenosis. We used comprehensive rehabilitation care interventions on patients.

Results: Among 294 patients, 253 (86.05%) were finally diagnosed with AIS. The sensitivity and specificity of head and neck MRA images were 85.37% and 92.68%, respectively.

Conclusions: Examination can effectively assess cerebral hemodynamic changes, the severity of ischemia, and accurately distinguish between infarct area and penumbra. MRA images of the head and neck can accurately detect the location and degree of cerebral artery stenosis. The combination of the two methods can not only accurately diagnose AIS, but also evaluate the condition and efficacy of the disease, and provide an imaging basis for the clinical choice of reasonable treatment options. Comprehensive rehabilitation care can significantly improve the neurologic function and quality of life of prospective patients.
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http://dx.doi.org/10.1016/j.wneu.2020.10.135DOI Listing
May 2021

Stable isotopes verify geographical origin of yak meat from Qinghai-Tibet plateau.

Meat Sci 2020 Jul 14;165:108113. Epub 2020 Mar 14.

Institute of Quality and Standard of Agricultural Product, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt 5040, New Zealand. Electronic address:

High-value yak meat from Qinghai-Tibet Plateau was investigated using stable isotopes (δC, δH, δO, δN and δS) to identify attributes which could verify and protect its geographical origin. Supervised PLS-DA was applied to the isotope data to discriminate four geographical locations. δC, δH, and δO values showed significant differences according to origin while δN and δS values did not show any change across the different regions. Isotope values of different body tissues from the same animal showed no statistical difference for the five stable isotopes. In addition, the δH and δO values of defatted yak meat was highly correlated to farm altitude and associated drinking water. This yak meat traceability method is particularly useful to protect the Product of Geographical Indication (PGI) status of Gannan yak meat and verify the farming origin of yak meat sold in markets for food safety purposes, especially when excessive hormones, pesticides or heavy metals are found.
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http://dx.doi.org/10.1016/j.meatsci.2020.108113DOI Listing
July 2020

The role of upstream stimulatory factor 1 in the transcriptional regulation of the human TBX21 promoter mediated by the T-1514C polymorphism associated with systemic lupus erythematosus.

Immunogenetics 2012 May 19;64(5):361-70. Epub 2012 Jan 19.

Institute of Infectious Diseases, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.

T-bet is a key regulator for the lineage commitment in CD4+ T helper (Th) 1 cells by activating the hallmark production of interferon-γ. Previously, two single nucleotide polymorphisms (SNPs) in the TBX21 promoter, T-1993C and T-1514C, have been shown by statistic studies to associate with systemic lupus erythematosus (SLE). The effect of -1993 SNP on the Yin Yang 1 transcription factor-mediated promoter activity has been already indicated. This study aimed to investigate roles of the T-1514C SNP on TBX21 transcription and its functional effect by luciferase reporter, electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP) assay, and flow cytometric analysis of intracellular T-bet, IFN-γ, and IL-4 expression in activated CD4+ T cells. The TBX21 promoter carrying -1514C possessed significantly lower transcriptional activity than that of -1514T and was markedly downregulated by the overexpression of upstream stimulatory factor 1 (USF-1) when compared with the promoter carrying -1514T. EMSA indicated that the transcription factor USF-1 was bound to the -1514C allele probe with the affinity higher than that to the -1514T allele probe. ChIP assay suggested that USF-1 bound around -1514 of TBX21 genomic DNA in vivo in the human T cell line Jurkat with -1514C/T. The individuals carrying -1514C allele were determined to have significantly diminished expression of T-bet and IFN-γ and increased IL-4 production in CD4+ T cells compared with those of -1514T allele. The findings demonstrate that the T-1514C polymorphism affects TBX21 gene expression and Th1 cytokine production by binding USF-1 to the SNP site.
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http://dx.doi.org/10.1007/s00251-011-0597-6DOI Listing
May 2012