A novel in-situ dynamic mechanical analysis for human plantar soft tissue: The device design, definition of characteristics, test protocol, and preliminary results.

The in-situ mechanical characterization of elastomers is not highly regarded due to the existence of a well-established set of sample-based standard tests for research and industry. However, there are certain situations or materials, like biological soft tissue, where an in-situ approach is necessary due to the impossibility of sampling from a living body. We have developed a dynamic mechanical analysis (DMA)-like device to approach in-vivo and in-situ multidimensional stress-strain properties of human plantar soft tissues. This work elucidates the operational mechanism of the novel measurement, with the definition of a new set of moduli, test standardization and protocol. Exploratory results of a volunteer's living plantar, silica rubber samples are presented with well preciseness and consistence as expected.

An exploratory in-situ dynamic mechanical analysis on the shearing stress-strain mechanism of human plantar soft tissue.

A DMA (dynamic mechanical analysis)-like device based on the principle of classical viscoelasticity testing is invented to investigate the in-situ/in-vivo shear-bearing mechanism of plantar soft tissue. Forty-three volunteers were recruited for the shear-strain test in the longitudinal and transverse directions at five anatomical spots on the plantar surface. Several encouraging observations indicated significant variances among different spots and individuals, implying that the outer forefoot surrounding the second, fifth metatarsal head is a more intensive shear-bearing region on the plantar surface compared to the inner forefoot under the first metatarsal head, and drawing the hypothesis of a significant effect of BMI on the shear-bearing property. The speculations agree with our expectations and other previous research. The feasibility and practical value of this novel approach are substantiated, and these intriguing discoveries provide foundational underpinnings for further in-depth investigations.

Reduction of the trans-cortical vessel was associated with bone loss, another underlying mechanism of osteoporosis.

RATIONALE: Numerous studies have established a robust association between bone morrow microvascular diseases and osteoporosis. This study sought to investigate the relationship between alterations in trans-cortical vessel (TCVs) and the onset of osteoporosis in various mouse models. METHODS: Aged mice, ovariectomized mice, and db/db mice, were utilized as osteoporosis models. TCVs in the tibia were detected using tissue clearing and light sheet fluorescence microscopy imaging. Femurs bone mass were analyzed using micro-CT scanning. Correlations between the number of TCVs and bone mass were analyzed using Pearson correlation analysis. RESULTS: All osteoporosis mouse models showed a significant reduction in the number of TCVs compared to the control group. Correlation analysis revealed a positive association between the number of TCVs and bone mass. TCVs were also expressed high levels of CD31 and EMCN proteins as type H vessels. CONCLUSIONS: This study underscores a consistent correlation between the number of TCVs and bone mass. Moreover, TCVs may serve as a potential biomarker for bone mass evaluation.

N-acetyl-L-cysteine attenuates oxidative stress-induced bone marrow endothelial cells apoptosis by inhibiting BAX/caspase 3 pathway.

Bone marrow endothelial cells (BMECs) play a crucial role in the maintenance of bone homeostasis. The decline in BMECs is associated with abnormal bone development and loss. At present, the mechanism of age-related oxidative stress enhancement in BMEC dysfunction remains unclear. Our experiment explored injury caused by oxidative stress enhancement in BMECs both in vivo and in vitro. The BMECs, indicators of oxidative stress, bone mass, and apoptosis-related proteins were analyzed in different age groups. We also evaluated the ability of N-Acetyl-L-cysteine (NAC) attenuate oxidative stress injury in BMECs. NAC treatment attenuated reactive oxygen species (ROS) overgeneration and apoptosis in BMECs in vitro and alleviated the loss of BMECs and bone mass in vivo. In conclusion, this study could improve our understanding of the mechanism of oxidative stress-induced BMECs injury and whether NAC has therapeutic potential in senile osteoporosis.

Nurses' knowledge, attitude and behaviour on medical adhesive related skin injury in neonatal department: A survey.

AIM: To evaluate the status quo of knowledge, attitude and behaviour of neonatal nurses on medical adhesive related skin injury (MARSI). DESIGN: A survey. METHODS: We conducted a survey on the knowledge, attitude and behaviour of neonatal nurses from September 1-30, 2022. The characteristics, knowledge, attitude and behaviour of neonatal nurses were evaluated and analysed. RESULTS: A total of 116 neonatal nurses were included. Multivariate regression analysis indicated that had accepted MARSI training, education level, year of work experience are the influencing factors of nurses' MARSI knowledge score (all p < 0.05). Had accepted MARSI training, year of work experience are the influencing factors of nurses' MARSI attitude score (all p < 0.05). Had accepted MARSI training, year of work experience are the influencing factors of nurses' MARSI behaviour score (p = 0.015). PATIENT CONTRIBUTION: Neonatal nurses should strengthen their learning and training of MARSI related knowledge, and standardize their protective behaviours to reduce MARSI.

Aggregation-based phase transition tailored heterophase junctions of AgInS2 for boosting photocatalytic H2 evolution.

Due to high defect tolerance and multiphase allowance, AgInS2 (AIS) quantum dots (QDs) provide chances for designing new type junctions via tailoring defects, size, or phase structure. These new type junctions potentially enhance photoelectric performance, such as photocatalytic H2 evolution (PHE). Here, ultra-small AIS QDs (∼1 nm) with well-defined exciton absorption were prepared aqueously via a reverse hot-injection procedure for the first time. A coalescence or fast aggregation-based growth was observed for coarsening at 95 or 135 ℃, respectively. XRD and TEM investigations revealed that the tetragonal-orthorhombic (t-o) phase transition occurred via aggregation-based growth. The studies on phase transition kinetics resulted in fine-tailoring on AIS polymorphs, favoring t-o AIS junctions. UV-vis absorption spectra confirm the double absorption edge of the t-o heterophase junction with enhanced visible absorption. Steady and transient PL spectra suggest improvements in carriers' separation/transfer in this t-o junction. As a result, the optimized t-o AIS shows superior photocatalytic H2 evolution rates of 1022 µmol. g-1. h-1, 51.1 times that of t-AIS or 3.8 times that of o-AIS. This work is expected to provide new insight for designing ternary alloyed QDs with strongly coupled interfaces for effective H2 generations.

Plexin B2 and Semaphorin 4C Guide T Cell Recruitment and Function in the Germinal Center.

Follicular T helper (TFH) cells orchestrate the germinal center (GC) response locally. TFH localization in GCs is controlled by chemo-guidance cues and antigen-specific adhesion. Here. we define an antigen-independent, contact-dependent, adhesive guidance system for TFH cells. Unusual for amoeboid cell migration, the system is composed of transmembrane plexin B2 (PlxnB2) molecule, which is highly expressed by GC B cells, and its transmembrane binding partner semaphorin 4C (Sema4C), which is upregulated on TFH cells. Sema4C on TFH cells serves as a receptor to sense the GC-presented PlxnB2 cue and biases TFH migration inwards at the GC edge to promote GC access. The absence of PlxnB2 from the GC or Sema4C from TFH cells causes TFH accumulation along the GC border, impairs T-B cell interactions in the GC, and is associated with defective plasma cell production and affinity maturation. Therefore, Sema4C and PlxnB2 regulate GC TFH recruitment and function and optimize antibody responses.

Donepezil delays photoreceptor apoptosis induced by N-methyl-N-nitrosourea in mice.

Retinitis pigmentosa (RP) is a group of inherited retinal degeneration diseases characterized by photoreceptor cell death that causes visual disturbances and eventual blindness. Intraperitoneal injection of N-methyl-N-nitrosourea (MNU) causes photoreceptor loss, and is used to create an animal model for investigating the mechanisms that cause retinal degeneration diseases. Donepezil is an acetylcholinesterase inhibitor that has a protective effect on retinal ganglion cells in vitro and in vivo, and it is understood that donepezil increases the expression of a heat shock protein 70 (Hsp70), which serves to protect neurons. Hsp70 functions as a chaperone molecule that protects cells from protein aggregation and assists in the refolding of denatured proteins. In the present study, the effects of donepezil on photoreceptor survival in mice was investigated. It was observed that donepezil upregulates the expression of Hsp70, to increase resistance to MNU-induced photoreceptor cell apoptosis by using its anti-apoptotic properties. In addition, the present study observed that Hsp70 promotes photoreceptor cell survival by upregulating the expression levels of B-cell lymphoma 2 (Bcl-2). In conclusion, the results of the present study indicate that donepezil has the potential to be used as a treatment for retinal degenerative diseases.

Phenotypic Tfh development promoted by CXCR5-controlled re-localization and IL-6 from radiation-resistant cells.

How follicular T-helper (Tfh) cells develop is incompletely understood. We find that, upon antigen exposure in vivo, both naïve and antigen-experienced T cells sequentially upregulate CXCR5 and Bcl6 within the first 24 h, relocate to the T-B border, and give rise to phenotypic Bcl6(+)CXCR5(+) Tfh cells before the first cell division. CXCR5 upregulation is more dependent on ICOS costimulation than that of Bcl6, and early Bcl6 induction requires T-cell expression of CXCR5 and, presumably, relocation toward the follicle. This early and rapid upregulation of CXCR5 and Bcl6 depends on IL-6 produced by radiation-resistant cells. These results suggest that a Bcl6(hi)CXCR5(hi) phenotype does not automatically define a Tfh lineage but might reflect a state of antigen exposure and non-commitment to terminal effector fates and that niches in the T-B border and/or the follicle are important for optimal Bcl6 induction and maintenance.

Nuclear receptors of the NR4a family are not required for the development and function of follicular T helper cells.

Follicular T helper (Tfh) cells promote germinal center (GC) reaction and high-affinity antibody production. The molecular mechanisms that regulate development and function of Tfh cells are not fully understood. Here we report that ligand-independent nuclear receptors of the Nr4a family are highly expressed in Tfh cells. In a well-established adoptive transfer model, enforced expression of Nr4a receptors reduces helper T cell expansion but apparently increased the T cell capacity to promote the GC response. On the other hand, deletion of all Nr4a receptors in T cells did not significantly affect expansion or differentiation of Tfh cells or the development of GC reaction. These findings suggest that Nr4a receptors may promote but are not necessary for Tfh development or function in vivo.

Tfh cell differentiation and their function in promoting B-cell responses.

Follicular helper T cells (Tfh) are a newly defined helper T-cell subset that is specialized in facilitating B-cell responses. These cells have a unique tissue localization pattern and a distinct transcriptional program suited for the B-cell helper function. Co-opting of the follicular program affords regulatory T cells, NK T cells, and γδ T cells with opportunities to participate in the regulation of humoral immunity. Abnormal Tfh development and function can lead to immunodeficiencies, autoimmune inflammation, and tumors. Detailed understanding of Tfh cell differentiation and function in animal models and the human system promises better strategies toward vaccine development and therapies for inflammatory diseases.

SAP-regulated T Cell-APC adhesion and ligation-dependent and -independent Ly108-CD3ζ interactions.

The germinal center response requires cooperation between Ag-specific T and B lymphocytes, which takes the form of long-lasting cell-cell conjugation in vivo. Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is required for stable cognate T-B cell conjugation, whereas SLAM family transmembrane (TM) receptor Ly108 may negatively regulate this process. We show that, other than phosphotyrosine-binding, SAP does not harbor motifs that recruit additional signaling intermediates to stabilize T-B adhesion. Ly108 dampens T cell adhesion to not only Ag-presenting B cells, but also dendritic cells by inhibiting CD3ζ phosphorylation through two levels of regulated Ly108-CD3ζ interactions. Constitutively associated with Src homology 2 domain-containing tyrosine phosphatase-1 even in SAP-competent cells, Ly108 is codistributed with the CD3 complex within a length scale of 100-200 nm on quiescent cells and can reduce CD3ζ phosphorylation in the absence of overt TCR stimulation or Ly108 ligation. When Ly108 is engaged in trans during cell-cell interactions, Ly108-CD3ζ interactions are promoted in a manner that uniquely depends on Ly108 TM domain, leading to more efficient CD3ζ dephosphorylation. Whereas replacement of the Ly108 TM domain still allows the constitutive, colocalization-dependent inhibition of CD3ζ phosphorylation, it abrogates the ligation-dependent Ly108-CD3ζ interactions and CD3ζ dephosphorylation, and it abolishes the suppression on Ag-triggered T-B adhesion. These results offer new insights into how SAP and Ly108 antagonistically modulate the strength of proximal TCR signaling and thereby control cognate T cell-APC interactions.

Identification of a new isoform of the murine Sh2d1a gene and its functional implications.

Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is a Src homology (SH) domain 2-containing intracellular adaptor protein that is predominantly expressed in the hematopoietic system by T lymphocytes and NK cells. SAP protein is encoded by the SH2D1A gene located on the X chromosome. Loss-of-function mutations in SAP cause the X-linked lymphoproliferative disease (XLP), a severe immunodeficiency characterized by heightened susceptibility to Epstein-Barr virus and impaired humoral immunity. Normal individuals express several functional and non-functional isoforms of SAP as a result of alternative splicing. In this study, we identify a cryptic exon in the murine Sh2d1a gene. At the mRNA level, the new isoform of SAP (SAP-2) that includes this new exon is widely expressed in lymphoid tissues by C57BL/6 and 129 strains of inbred mice. SAP-2 accounts for approximately 1%-3% of total SAP transcripts, and it is dynamically regulated during lymphocyte activation. At the protein level, the SAP-2 isoform is a 144 amino-acid protein. Compared to the dominant 126 aminoacid SAP-1 isoform, the additional 18 amino acids are inserted into a structural region that is critical for phosphotyrosine binding. Our functional analysis in vitro indicates that SAP-2 is a non-functional isoform due to decreased protein stability. Thus, both human and mouse have multiple SAP splice isoforms that may or may not function. Modulation of relative proportions of these isoforms is potentially a mechanism whereby cells can regulate SAP-mediated biological activities.

HMBOX1, homeobox transcription factor, negatively regulates interferon-γ production in natural killer cells.

HMBOX1 is a new member of homeobox family and predicted to be a transcriptional repressor, its function in NK cells is completely unclear. Previously we found that overexpression of HMBOX1 downregulated mRNA level of IFN-γ in NK cells during our gene screening work. In present study, we investigate the relationship between HMBOX1 and IFN-γ in detail. Firstly, we describe the properties of HMBOX1 gene transcription in activated NK cells, and found that the transcriptional levels of HMBOX1 were significantly decreased in NK cells after activated by IL-2, IL-15 and IL-12, which was opposite to the expression profile of IFN-γ. Subsequently, over-expression of HMBOX1 significantly inhibited the expression and production of IFN-γ in NK cells in response to the stimulation of tumor cell K562 or PMA/ionomycin. Additionally, by luciferase reporter assay, HMBOX1 displayed suppressive effect on the transcription activity of IFN-γ promoter. These findings indicated that HMBOX1 may function as a negative regulator of IFN-γ in NK cells.

HMBOX1 negatively regulates NK cell functions by suppressing the NKG2D/DAP10 signaling pathway.

HMBOX1 is a new member of the homeobox family. Homeobox members have been reported to participate in embryonic development and systemic metabolism, but the function of HMBOX1 remains unclear, especially in the hematopoietic system. Here, we show that HMBOX1 is expressed at a high level in primary human NK cells but is expressed at much lower levels in NK cell lines. Overexpression of HMBOX1 significantly inhibited NK cell activities, including natural cytotoxicity against tumor cells, the level of CD107a (a marker protein for degranulation) and the production of cytolytic proteins (perforin and granzymes). More interestingly, HMBOX1 negatively regulated the expression of NKG2D and the activation of the NKG2D/DAP10 signaling pathway in NK cells. This effect was reversed by knocking down HMBOX1. Taken together, these findings demonstrate that HMBOX1 may act as a negative regulator of NK cell functions via suppressing the NKG2D/DAP10 signaling pathway.

NK cell-based approach for screening novel functional immune genes.

The human genome project provides extensive opportunities for the discovery of novel functional immune genes. In order to find innate immune genes that might regulate the function of NK cells from a cDNA library, we used an NK cell line, NK-92, as a platform to screen candidate genes. After comparing with other gene transfer methods, electroporation was selected as the best gene transfection approach to deliver cDNA expression plasmids containing candidate genes into the NK-92 cells. When the transferred gene was stably expressed in NK-92 cells, the functional changes in the NK-92 cells were examined, including cytotoxicity, cytolytic molecules, cytokine production, and proliferation. Two novel genes were selected as functional genes that regulate NK cell function from among more than 100 candidate genes, for which the proliferation and cytotoxicity of NK-92 cells were examined as primary indicators. This was followed by extensive flow cytometry analysis and RT-PCR. The primary data indicated that the two novel genes negatively influenced the cytotoxicity of NK-92 cells by inhibiting the expression of several activating receptors and immune functional genes. Therefore, we describe an efficient method for the discovery of novel functional genes in NK cells by using an NK cell line as a screening platform.

Recombinant expression of a novel human transcriptional repressor HMBOX1 and preparation of anti-HMBOX1 monoclonal antibody.

HMBOX1 was a novel transcription factor possibly involving in function of pancreas and cytotoxicity of NK cells. For function determination, recombinant human HMBOX1 protein was obtained and purified, and the monoclonal antibodies against HMBOX1 were prepared. The full-length cDNA fragment encoding HMBOX1 was amplified from NK-92 cells and inserted into prokaryotic expression vector pET22b. The pET22b-HMBOX1-6his vector was then transformed into E. coli Rosetta (DE3) and induced by 1 mM IPTG for 4 h at 37 degrees Celsius. The fusion HMBOX1 protein was mainly expressed in inclusion bodies, which was purified and refolded using Ni2+-affinity chromatography. With the purified fusion HMBOX1 protein as antigen, monoclonal antibodies against HMBOX1 were generated, providing a potentially useful tool for further study in HMBOX1 functions. Using these anti-HMBOX1 mAbs, we identified that HMBOX1 is located in both cytoplasm and nucleus and could be detected in 10 human normal tissues, including cerebrum, pancreas, kidney and liver tissues. Moreover, the expression in hepatic carcinoma was significantly lower than that in adjacent tissues.