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Bin Chen

Publications and source records attributed to Bin Chen.

At least 19 recordsLinked to original sources
PubMed2026

A species-discriminatory aerA TaqMan qPCR assay for rapid quantification of Aeromonas veronii in fish tissues and aquaculture water.

Aeromonas veronii is a major bacterial pathogen in freshwater aquaculture, yet rapid species-level quantification remains challenging within the genetically complex genus Aeromonas. We developed a singleplex hydrolysis-probe (TaqMan) quantitative PCR (qPCR) assay targeting an A. veronii-discriminatory region of the aerolysin gene (aerA) and validated it according to MIQE recommendations. Plasmid standards gave a linear range of 2 to 2 × 106 copies/reaction (R2 = 0.9962) with 100.5% amplification efficiency. The endpoint limit of detection was 2 copies per reaction, and 20 copies per reaction was set as the practical reporting limit based on reproducible detection and low intra- and inter-assay variation. Analytical specificity was evaluated with genomic DNA from an 18-strain panel, with reproducible amplification observed only for A. veronii. The assay was further tested in 55 fish-tissue and 11 aquaculture-water DNA extracts. NH8B-1D2 sample-process monitoring was used for matrix-level recovery correction, and tissue and water extraction blanks were undetermined. The aerA target was detected in all tested gill, stomach/intestine, spleen, kidney/head kidney, pond-water filter and Xiamen seawater filter extracts, and in 10/11 liver extracts. Median NH8B-corrected loads were highest in gill among tissues and higher in pond-water filters than in Xiamen seawater filters. A separate Vibrio harveyi inhibition-check assay indicated no obvious amplification-stage inhibition. This assay supports rapid quantification of aerA-positive A. veronii in fish and aquaculture-water matrices.

Animals↗
PubMed2026

Responding to a protracted tuberculosis outbreak: lessons from multiple rounds of investigation in a Chinese boarding school.

PURPOSE: This study analysed a multi-semester pulmonary tuberculosis (PTB) cluster outbreak in a Chinese boarding school to provide evidence for future epidemic control. METHODS: Contacts were screened via symptoms, infection tests and chest radiography. Screening expanded progressively from close contacts to same-floor contacts, then all students and staff. Whole-genome sequencing (WGS) with single nucleotide polymorphism (SNP) and bioinformatics analysis was used for lineage classification, transmission clustering (&#x2264;12 SNPs defining a cluster) and drug resistance prediction. RESULTS: From 2020 to 2022, 20 students were diagnosed with PTB, half laboratory-confirmed. Most cases clustered in class 16 and were epidemiologically linked to the primary case (case 0), who had household PTB exposure. Case 0 and case 1 had diagnostic delays exceeding 3 and 6&#xa0;months, respectively. WGS of five isolates (case 1, 3, 4, 9 and 10) collected over three semesters showed all belonged to lineage 2 and differed by &#x2264;12 SNPs, confirming the same transmission chain. The infection rate in class 16 (46.34%) was significantly higher than other case classes (19.05%) and classes without cases (8.27%) (&#x3c7;2&#xa0;=&#xa0;61.169, p&#xa0;<&#xa0;0.001). No new cases were detected during a one-year follow-up of students involved in the outbreak after the final round of screening, nor among household contacts of all cases followed up to the present. CONCLUSIONS: Lack of entry health examinations facilitated the outbreak. Delayed diagnosis, incomplete contact screening and absence of preventive treatment led to cross-semester persistence. The infection rate disparity confirms class 16 as the outbreak epicentre. Improving community case management, extending contact follow-up and enhancing cluster outbreak measures are recommended to prevent future outbreaks.

Humans↗
PubMed2025

Pyramidal neurons proportionately alter the identity and survival of specific cortical interneuron subtypes.

The mammalian cerebral cortex comprises a complex neuronal network that maintains a precise balance between excitatory pyramidal neurons and inhibitory interneurons. Accumulating evidence indicates that specific interneuron subtypes form stereotyped microcircuits with distinct pyramidal neuron classes. Here we show that pyramidal neurons play an active role in this process by promoting the survival and terminal differentiation of their associated interneuron subtypes. In wild-type cortex, interneuron subtype abundance mirrors the prevalence of their pyramidal neuron partners. In Fezf2 mutants, which lack layer 5b pyramidal neurons and are expanded in layer 6 intratelencephalic neurons, corresponding subtype-specific shifts occur through two distinct mechanisms: somatostatin interneurons adjust their programmed cell death, whereas parvalbumin interneurons switch their subtype identity. Silencing neuronal activity or blocking vesicular release in L5b pyramidal neurons revealed that their communication with interneurons does not require voltage-gated synaptic activity and engages both tetanus toxin-sensitive and -insensitive pathways. Moreover, a targeted bioinformatic screen for ligand-receptor pairs displaying subtype-specific expression and reduced expression of pyramidal neuron-derived ligand in Fezf2 mutants identified candidate secreted factors and adhesion molecules. These findings reveal distinct, pyramidal neuron-driven mechanisms for sculpting interneuron diversity and integrating them into local cortical circuits.

Journal Article↗
PubMed2024

A conserved molecular logic for neurogenesis to gliogenesis switch in the cerebral cortex.

During development, neural stem cells in the cerebral cortex, also known as radial glial cells (RGCs), generate excitatory neurons, followed by production of cortical macroglia and inhibitory neurons that migrate to the olfactory bulb (OB). Understanding the mechanisms for this lineage switch is fundamental for unraveling how proper numbers of diverse neuronal and glial cell types are controlled. We and others recently showed that Sonic Hedgehog (Shh) signaling promotes the cortical RGC lineage switch to generate cortical oligodendrocytes and OB interneurons. During this process, cortical RGCs generate intermediate progenitor cells that express critical gliogenesis genes Ascl1, Egfr, and Olig2. The increased Ascl1 expression and appearance of Egfr+ and Olig2+ cortical progenitors are concurrent with the switch from excitatory neurogenesis to gliogenesis and OB interneuron neurogenesis in the cortex. While Shh signaling promotes Olig2 expression in the developing spinal cord, the exact mechanism for this transcriptional regulation is not known. Furthermore, the transcriptional regulation of Olig2 and Egfr has not been explored. Here, we show that in cortical progenitor cells, multiple regulatory programs, including Pax6 and Gli3, prevent precocious expression of Olig2, a gene essential for production of cortical oligodendrocytes and astrocytes. We identify multiple enhancers that control Olig2 expression in cortical progenitors and show that the mechanisms for regulating Olig2 expression are conserved between the mouse and human. Our study reveals evolutionarily conserved regulatory logic controlling the lineage switch of cortical neural stem cells.

Animals↗
PubMed2022

Reversal of cancer gene expression identifies repurposed drugs for diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine glioma (DIPG) is an aggressive incurable brainstem tumor that targets young children. Complete resection is not possible, and chemotherapy and radiotherapy are currently only palliative. This study aimed to identify potential therapeutic agents using a computational pipeline to perform an in silico screen for novel drugs. We then tested the identified drugs against a panel of patient-derived DIPG cell lines. Using a systematic computational approach with publicly available databases of gene signature in DIPG patients and cancer cell lines treated with a library of clinically available drugs, we identified drug hits with the ability to reverse a DIPG gene signature to one that matches normal tissue background. The biological and molecular effects of drug treatment was analyzed by cell viability assay and RNA sequence. In vivo DIPG mouse model survival studies were also conducted. As a result, two of three identified drugs showed potency against the DIPG cell lines Triptolide and mycophenolate mofetil (MMF) demonstrated significant inhibition of cell viability in DIPG cell lines. Guanosine rescued reduced cell viability induced by MMF. In vivo, MMF treatment significantly inhibited tumor growth in subcutaneous xenograft mice models. In conclusion, we identified clinically available drugs with the ability to reverse DIPG gene signatures and anti-DIPG activity in vitro and in vivo. This novel approach can repurpose drugs and significantly decrease the cost and time normally required in drug discovery.

Humans↗
PubMed2007

Distribution and property of nerve fibers in human long bone tissue.

OBJECTIVE: To observe the distribution of the nerve fibers in the bone tissue and the entry points of these fibers into the bone. METHODS: The adult tibia was used for the ground sections which were afterwards made into the slice sections by decalcification in ethylenediamine tetraacetic acid (EDTA). The ground sections were stained in silver and the slice sections were stained in silver and haematoxylin and eosin (HE) respectively. Then, the samples of the transmission electron microscope and the atomic force microscope were made and observed. RESULTS: In the human long bone tissue, many nerve fibers were distributed in the membrane, cortical bone, cancellous bone and marrow. The nerve fibers entered the bone from the nutrient foramen, and passed through the nutrient canal, Haversian's canal and Volkmann's canal, and finally into the bone marrow. In the nutrient canal, the nerve fibers, mainly the medullary nerve fibers, followed the blood vessel into the bone. In the cortical bone, the nerve fibers also followed the blood vessels and were mainly distributed along Haversian's canal and Volkmann's canal. In the bone trabecular and bone marrow, there were many nerve fiber endings arranged around the blood vessels, mainly around the tunica media of medium-size arteries in the marrow and around capillary blood vessels, and a few scattered in the bone marrow. There were sporadic nerve endings in epiphyseal plate and no nerve fibers permeated epiphysis to diaphysis. No distribution of nerve fibers could be found in cartilaginous part. CONCLUSIONS: There are many nerve fibers in bone and the nerve passageway is nutrient foramen, Volkman's canal, Haversian's canal and bone marrow.

Adult↗
PubMed2006

Cell cycle inhibition attenuates microglia induced inflammatory response and alleviates neuronal cell death after spinal cord injury in rats.

The spinal cord is well known to undergo inflammatory reactions in response to traumatic injury. Activation and proliferation of microglial cells, with associated proinflammatory cytokines expression, plays an important role in the secondary damage following spinal cord injury. It is likely that microglial cells are at the center of injury cascade and are targets for treatments of CNS traumatic diseases. Recently, we have demonstrated that the cell cycle inhibitor olomoucine attenuates astroglial proliferation and glial scar formation, decreases lesion cavity and mitigates functional deficits after spinal cord injury (SCI) in rats [Tian, D.S., Yu, Z.Y., Xie, M.J., Bu, B.T., Witte, O.W., Wang, W., 2006. Suppression of astroglial scar formation and enhanced axonal regeneration associated with functional recovery in a spinal cord injury rat model by the cell cycle inhibitor olomoucine. J. Neurosci. Res. 84, 1053-1063]. Whether neuroprotective effects of cell cycle inhibition are involved in attenuation of microglial induced inflammation awaits to be elucidated. In the present study, we sought to determine the influence of olomoucine on microglial proliferation with associated inflammatory response after spinal cord injury. Tissue edema formation, microglial response and neuronal cell death were quantified in rats subjected to spinal cord hemisection. Microglial proliferation and neuronal apoptosis were observed by immunofluorescence. Level of the proinflammatory cytokine interleukin-1beta (IL-1beta) expression in the injured cord was determined by Western blot analysis. Our results showed that the cell cycle inhibitor olomoucine, administered at 1 h post injury, significantly suppressed microglial proliferation and produced a remarkable reduction of tissue edema formation. In the olomoucine-treated group, a significant reduction of activated and/or proliferated microglial induced IL-1beta expression was observed 24 h after SCI. Moreover, olomoucine evidently attenuated the number of apoptotic neurons after SCI. Our findings suggest that modulation of microglial proliferation with associated proinflammatory cytokine expression may be a mechanism of cell cycle inhibition-mediated neuroprotections in the CNS trauma.

Analysis of Variance↗
PubMed2006

Cloning and characterization of the HSP70 Gene, and its expression in response to diapauses and thermal stress in the onion maggot, Delia antiqua.

The cytosolic members of the HSP70 family of proteins play key roles in the molecular chaperone machinery of the cell. In the study we cloned and sequenced the fulllength cDNA of Delia antiqua HSP70 gene, which is 2461 bp long and encodes 643 a.a. with a calculated molecular mass of 70,787 Da. We investigated gene copies of cytosolic HSP70 members of 4 insect species with complete genome available, and found that they are quite variable with species. In order to characterize this protein we carried out an alignment and a phylogenetic analysis with 41 complete protein sequences from insects. The analysis divided the cytosolic members of the family into two classes, HSP70 and HSC70, distinguishable on the basis of 15 residues. HSP70 class members were slightly shorter in length and smaller in molecular mass relative to the HSC70 class members, and the conservative and functional regions in these sequences were documented. Mainly, we investigated the expression of Delia antiqua HSP70 gene, in response to diapauses and thermal stresses. Both summer and winter diapauses elevated HSP70 transcript levels. Cold-stress led to increased HSP70 expression levels in summer- and winter-diapausing pupae, but heat-stress elevated the levels only in the winter-diapausing pupae. In all cases, the expression levels, after being elevated, gradually decreased with time. HSP70 expression was low in non-diapausing pupae but was up-regulated following cold- and heatstresses. Heat-stress gradually increased the mRNA level with time whereas cold-stress gradually decreased levels after an initial increase.

Amino Acid Sequence↗
PubMed2006

Whole-body three-dimensional contrast-enhanced magnetic resonance (MR) angiography with parallel imaging techniques on a multichannel MR system for the detection of various systemic arterial diseases.

Using a 1.5-T magnetic resonance (MR) imager equipped with 32 receiving channels and integrated parallel acquisition techniques, 37 patients underwent whole-body three-dimensional (3D) contrast-enhanced MR angiography (WB 3D CE MRA). The patients included had clinically documented or suspected peripheral arterial occlusive disease (PAOD, n = 19), Takayasu arteritis (n = 8), polyarteritis nodosa (n = 1), type-B dissection (n = 4), thoracic and/or abdominal aneurysm (n = 5). Sixty-eight surface coils were employed to encompass the whole body. Four 3D CE MRA stations were acquired successively through automatic table moving. The spatial resolution was 1.6 x 1.0 mm and slice thickness was 1.5 mm for all stations. A total scan range of 188 cm was acquired. Overall image quality of each arterial segment and venous overlay were assessed. The depiction of various systemic arterial diseases was evaluated and compared, in 20 patients, with other imaging modalities. This WB 3D CE MRA yielded a detailed display of the arterial system with an average MR room time of 17.4 min. The image quality was considered diagnostic in 99.3% of the arterial segments. In 7 of 19 patients with PAOD, WB MRA showed additional vascular narrowing apart from peripheral arterial disease. In nine patients with vasculitis, WB MRA depicted luminal irregularity, narrowing or occlusion, aneurysm, and collateral circulation involving multiple vascular segments. WB MRA also clearly revealed the severity and extent of dissection and aortic aneurysm. In 20 cases where additional imaging investigations have been carried out, the vascular pathologies demonstrated by WB MRA agree with these additional imaging investigations.

Adolescent↗
PubMed2006

Diagnosis of systemic arterial diseases with whole-body 3D contrast-enhanced magnetic resonance angiography.

BACKGROUND: With the development of magnetic resonance (MR) technologies, whole-body 3D contrast-enhanced MR angiography (3D CE MRA) has become possible. The purpose of this study was to introduce and evaluate this technique in demonstration of various systemic arterial diseases. METHODS: Thirty-seven patients underwent whole-body 3D CE MRA using a 1.5T MR imager. The patients included were with clinically documented or suspected peripheral arterial occlusive disease (PAOD, n = 19), Takayasu arteritis (n = 8), polyarteritis nodosa (n = 1), Type B dissection (n = 4) and thoracic and/or abdominal aneurysm (n = 5). Sixty-eight surface coil elements were employed to encompass the whole body. Four 3D CE MRA stations were acquired successively through automatic table moving. A total scan range of 188 cm, covering the arterial tree from carotid artery to trifurcation vessels, was acquired. Overall image quality of each arterial segment and venous overlay were assessed and rated. The depiction of various systemic arterial diseases was evaluated and compared with other imaging modalities if available, including digital subtraction angiography (DSA), CT angiography, dedicated mono-station MRA. RESULTS: Whole-body 3D CE MRA was well tolerated by all patients. It yielded a detailed display of the arterial system with a short examination time. The image quality was considered diagnostic in 99.3% of the arterial segments. The remaining 0.7% of the arterial segments were considered non-diagnostic. In 7 of 19 patients with PAOD, whole-body MRA showed additional vascular narrowing apart from peripheral arterial disease. In 9 patients with vasculitis, whole-body MRA depicted luminal irregularity, narrowing or occlusion, aneurysm and collateral circulation involving multiple vascular segments. Whole-body MRA also clearly revealed the severity and extent of dissection and aortic aneurysm. In 20 cases the vascular pathologies demonstrated on whole body MRA were confirmed by other imaging investigations. CONCLUSIONS: The whole-body MRA technique was non-invasive, quick and easy to perform. It was valuable for a comprehensive evaluation of vascular involvement of various systemic arterial diseases.

Adolescent↗
PubMed2006

Water mediated attraction between repulsive ions: a cluster-based simulation approach.

Could two like ions be attractive to each other in the presence of water? To address this question and to further interrogate the intriguing solvent effects at a molecular level on multiply charged species, a "bottom-up" simulation approach was formulated, from which the inter-ionic potential of mean force and other properties were monitored closely with the gradual addition of the water molecules. This approach was first tested on a commonly studied ion pair (namely, Na+ and Cl-), where excellent agreement with the published bulk-phase data was found. Further application of this approach to the like-ion pair indicated that an attractive interaction between two anions or two cations can be induced by the addition of an appropriate number of water molecules. This result corroborates a recent experimental report of an intriguing folding of a dianionic polymer into a more compact structure with the addition of water molecules in gas phase as well as previous theoretical findings of possible attraction between like-ion pairs in bulk aqueous phases.

Chlorides↗
PubMed2006

Theoretical model for the pulse dynamics in a long granular chain.

When a long line of initially stationary and unstressed touching particles is hit on one end by another particle, dynamical self-organized impulsive waves will be generated and propagating through the granular chain. In this paper we develop a continuous function to represent the initial impulse wave. Then the partial differential wave equations for chains of cylindrical granules, which can take such function as one of its solutions, are constructed and exactly coincided with the wave equation obtained by using Taylor series expansion. The properties of the impulse wave propagating, such as the attenuation of the wave and the forward momentum transfer are studied in detail based on our theoretical model, and the analytical solutions are supported by numerical simulations.

Journal Article↗
PubMed2006

Probing the nucleation mechanism for the binary n-nonane/1-alcohol series with atomistic simulations.

The AVUS-HR approach, which combines histogram reweighting with aggregation-volume-bias Monte Carlo nucleation simulations using self-adaptive umbrella sampling, was extended to multicomponent nucleation systems. It was applied to investigate the homogeneous vapor-liquid nucleation for the binary n-nonane/1-alcohol series, including the n-nonane/methanol, n-nonane/ethanol, n-nonane/1-propanol, n-nonane/1-butanol, n-nonane/1-hexanol, and n-nonane/1-decanol systems. The simple transferable potentials for phase equilibria-united atom force field was used in this investigation. It was found that the nucleation free energy (NFE) contour plots obtained for these binary n-nonane/1-alcohol nucleation systems exhibit rather interesting mechanistic features, some of which are distinct from other binary systems previously studied (such as water/ethanol and water/n-nonane). In addition, the NFE profiles show a subtle evolution with the increase in alcohol chain length, from a somewhat two-pathway type of shape as observed for the n-nonane/methanol system to a more normal single-pathway one for systems involving longer alcohols (1-hexanol and 1-decanol). In contrast, the NFE maps obtained for the other three binary systems involving those medium-length alcohols display the most striking feature with the saddle point stretched almost all the way from the n-nonane-enriched to the alcohol-enriched domain, implying that multiple pathways coexist on the nucleation map. These free energy profiles were shown to be consistent with the non-ideal nucleation behavior observed experimentally for this binary series, namely, a rather reluctant conucleation of the alcohols with n-nonane. In particular, this non-ideal behavior becomes more severe with a decrease in the alcohol chain length. Also, analysis of the compositions of the critical nuclei indicates a reluctant mixing behavior between these two species, i.e., depletion of the alcohol at low alcohol activity or depletion of n-nonane at low n-nonane activity, in agreement with the experimental interpretations. Furthermore, a microscopic inhomogeneity is present inside these critical nuclei, that is, alcohols aggregate via hydrogen bonds forming alcohol-enriched domains.

Alcohols↗
PubMed2006

Switch between charge transfer and local excited states in 4-aminophenyl-substituted Hantzsch 1,4-dihydropyridine induced by pH change and transition metal ions.

The absorption and fluorescence spectra of a Hantzsch 1,4-dihydropyridine derivative bearing a N,N-dimethylaminophenyl group at 4-position (H(2)Py-PhN(CH(3))(2)) in aprotic solvents have been examined and compared to model compounds 4-phenyl- and 4-methyl-substituted Hantzsch 1,4-dihydropyridines (H(2)Py-Ph and H(2)Py-Me). While H(2)Py-Ph and H(2)Py-Me show fluorescence around 420 nm from the local excited state of the dihydropyridine chromophore, H(2)Py-PhN(CH(3))(2) exhibits fluorescence around 520 nm from the intramolecular charge transfer (ICT) state involving the aniline and dihydropyridine groups as donor and acceptor, respectively. Upon addition of an acid to the solution of H(2)Py-PhN(CH(3))(2), the amino group in the aniline is protonated. Thus, the photoinduced intramolecular charge transfer is prevented, and only the fluorescence from the local excited state of the dihydropyridine chromophore can be detected. These changes in the fluorescence behavior are fully reversible: subsequent addition of a base to the acidic solution leads to the recovery of the ICT fluorescence and the quenching of the local fluorescence. Transition metal ions also can switch the fluorescence of H(2)Py-PhN(CH(3))(2). Evidence for the interaction between transition metal ions and the amino group in the dimethylaniline have been provided by absorption and emission spectrum as well as NMR studies.

Aminophenols↗
PubMed2006

Anti-osteoporotic effect of Erythrina variegata L. in ovariectomized rats.

The present study was designed to investigate whether Erythrina variegata L. (EV), which belongs to the leguminous family, exerted any beneficial effects on bone in ovariectomized rats. Daily oral administration of the EV extract at 300 and 600 mg/kg for 14 weeks to rats prevented the OVX-induced increase in the serum OCN, ALP, and urinary DPD levels. Histomorphometric analysis of the proximal end of the tibia showed that the EV extract prevented the estrogen deficiency-induced decrease in trabecular thickness and trabecular area, as well as restoring the increase in trabecular separation in a dose-dependent manner. Moreover, the EV extract improved the energy absorption and stiffness of the mid-shaft of the rat femur. Thus, the present study clearly demonstrated that EV could suppress the high rate of bone turnover induced by estrogen deficiency, inhibit bone loss and improve the biomechanical properties of bone in the OVX rats.

Animals↗