Biomedical subjects

Zhongwei Chen

Publications and source records attributed to Zhongwei Chen.

17 recordsLinked to original sources

PubMed2025

Genomic and stress resistance characterization of Lactiplantibacillus plantarum GX17, a potential probiotic for animal feed applications.

UNLABELLED: Lactobacilli, recognized as beneficial bacteria within the human body, are celebrated for their multifaceted probiotic functions, including the regulation of intestinal flora, enhancement of body immunity, and promotion of nutrient absorption. This study comprehensively analyzed the genotypic and phenotypic characteristics of Lactiplantibacillus plantarum (L. plantarum) strains isolated from the intestines of healthy chicks and assessed their potential as probiotics. The assembled genome consists of 29,521,986 bp, and a total of 1,771 coding sequences (CDSs) were predicted. Based on the entire genome sequence analysis, 50 stress resistance genes and seven virulence factors were identified. The results of the phenotypic experiments showed that the strain had good resistance to high temperature, low temperature, acid, alkali, salt, artificial gastrointestinal fluid, and strong antioxidant capacity. Additionally, transcriptomic analysis confirmed that under stress conditions, the expression levels of key genes were significantly upregulated. Therefore, the phenotypic characteristics of L. plantarum GX17 align well with its genotypic features, demonstrating promising probiotic properties. This strain holds great potential as a probiotic candidate, and further investigation into its beneficial effects on human health is warranted. IMPORTANCE: In humans, Lactiplantibacillus plantarum may synergize with host microbiota to ameliorate dysbiosis-related pathologies, enhance immunomodulation, and facilitate micronutrient bioavailability. For livestock, its application could improve feed conversion ratios, suppress enteric pathogens through competitive exclusion, and mitigate antibiotic overuse, "a critical strategy in One Health frameworks." Further investigations into strain-specific mechanisms (e.g., postbiotic metabolites, quorum sensing regulation) are warranted to translate these genomic-phenotypic advantages into sustainable health solutions across species.

Probiotics↗

PubMed2006

Pt-Ru supported on double-walled carbon nanotubes as high-performance anode catalysts for direct methanol fuel cells.

Pt-Ru supported on carbon nanotubes (CNTs) (single-walled nanotubes, double-walled nanotubes (DWNTs), and multi-walled nanotubes) catalysts are prepared by an ethylene glycol reduction method. Pt-Ru nanoparticles with a diameter of 2-3 nm and narrow particle size distributions are uniformly deposited onto the CNTs. A simple and fast filtration method followed by a hot-press film transfer is employed to prepare the anode catalyst layer on a Nafion membrane. The Pt-Ru/DWNTs catalyst shows the highest specific activity for methanol oxidation reaction in rotating disk electrode experiments and the highest performance as an anode catalyst in direct methanol fuel cell (DMFC) single cell tests. The DMFC single cell with Pt-Ru/DWNTs (50 wt %, 0.34 mg Pt-Ru/cm(2)) produces a 68% enhancement of power density, and at the same time, an 83% reduction of Pt-Ru electrode loading when compared to Pt-Ru/C (40 wt %, 2.0 mg Pt-Ru/cm(2)).

Journal Article↗

PubMed2006

Multiple tumor types may originate from bone marrow-derived cells.

It was believed that tumors originated from the transformation of their tissue-specific stem cells. However, bone marrow-derived cells (BMDCs), which possess an unexpected degree of plasticity and often reside in other tissues, might also represent a potential source of malignancy. To study whether BMDCs play a role in the source of other tumors, BMDCs from mice were treated with 3-methycholanthrene until malignant transformation was achieved. Here we show that transformed BMDCs could form many tumor types, including epithelial tumors, neural tumors, muscular tumors, tumors of fibroblasts, blood vessel endothelial tumors, and tumors of poor differentiation in vivo. Moreover, a single transformed BMDC has the ability to self-renew, differentiate spontaneously into various types of tumor cells in vitro, express markers associated with multipotency, and form teratoma in vivo. These data suggest that multipotent cancer stem cells seemed to originate from transformed BMDCs. Conclusively, these findings reveal that BMDCs might be a source of many tumor types, even teratoma. In addition, multipotent cancer stem cells might originate from malignant transformed BMDCs.

Animals↗

PubMed2006

[Initial detection and analysis of neuro-information from amputee].

By detection and analysis of neuro-information from amputee in experiments, a research on the correlations of three main nerves (median nerve, radial nerve and ulnar nerve), on the patterns for discharging information, and on the mechanics about how neuro-information dominates movements was performed. These researches would contribute to the development of neuroprosthesis.

Adult↗

PubMed2005

Carbon nanotube film by filtration as cathode catalyst support for proton-exchange membrane fuel cell.

A simple filtration method is developed to prepare a partially oriented superhydrophobic film of carbon nanotubes (CNTs) that have been catalyzed with uniform small Pt nanoparticles (2.8 nm) at high metal loading (30 wt %). A proton-exchange membrane fuel cell with the oriented CNT film as the cathode achieves higher single-cell performance than those with carbon black and a disordered CNT-film-based cathode probably because of the enhanced electrocatalytic activity of Pt/CNT and improved mass transport within the oriented film.

Journal Article↗

PubMed2005

[Biomechanical experiment of non-stemmed anatomical total hip prosthesis arthroplasty in vitro].

Biomechanical test in vitro was performed to study the biomechanical characteristics of the femoral component in the non-stemmed anatomical total hip prosthesis (A-Fix) arthroplasty. It mimics two stages, the early stage with cementless and the later stage with cement fixation that imitates bone ingrowth. The results were compared with that of normal proximal femur by normalized coefficient analysis. Translation of femoral head after hip replacement is slightly more than normal. The strain of femoral neck after replacement is lower than that of normal. It changes flatly. The security coefficient in early stage is raised by 13% on the tensile side and by 27.6% on the compressive side of femoral neck; that in later stage is raised by 29.6% and by 22.1% separately. The maximal torsional angle of femoral head is minimal, it is 0.02 times that of normal in early stage and 0.01 times in later stage. It demonstrated that A-Fix arthroplasty has the characteristics of low stress and deformation, high intensity and rigidity, and anti-loosening, thus affording mechanical evidences for its clinical use.

Adult↗

PubMed2005

[An experimental study on repairing bone defect with the biodegradable polycaprolactone material].

OBJECTIVE: To investigate the ability of the biodegradable polycaprolactone (PCL) material to repair bone defect and to evaluate the feasibility of using the PCL as the scaffold in tissue engineering bone. METHODS: The bone defect models of 4. 5 mm x 12 mm were made in the bilateral femoral condyle of 65 New Zealand white rabbits. The PCL cylinder was implanted into the right side of defect (experimental group, n = 60), the high dense hydroxyapatite was implanted into the left side of defect (control group, n = 60), and the incision was sutured without any implants (blank group, n = 5). The samples were harvested and observed by examinations of gross, X-ray, bone density, 99mTc-MDP bone scanning, gamma-display ratio and scanning electron microscope (SEM) after 3, 6, 9 and 12 months of operation. The results were compared between the experimental group and control group. RESULTS: At 3, 6, 9 and 12 months after operation, the gross and X-ray examinations indicated that the bone defect filled with the new bone on the PCL-tissue surface, and no delayed inflammatory reaction appeared. The average bone mineral density was greater in the experimental group than that in the control group, and the difference had statistical significance (P< 0. 05). The results of 99mTc-MDP bone scanning and gamma-display ratio showed that the nuclide uptake was more in the PCL group than that in the control group. The SEM result proved that the new compact bone formed on the PCL migrating surface as the PCL degraded gradually,but the collagen fiber sheath formed around the hydroxyapatite in the control group. CONCLUSION: PCL possesses good biocompatibility and high bone inductive potentiality, it can be used to repair bone defect.

Absorbable Implants↗

PubMed2004

TEM investigation of formation mechanism of monocrystal-thick b-oriented pure silica zeolite MFI film.

The first direct transmission electron microscopic (TEM) observation has been carried out on the continuous monocrystal-thick b-oriented pure silica zeolite MFI films produced by in situ crystallization. The self-supporting film samples for TEM study were fabricated by dissolving the steel substrate with acid. This TEM study is free of those artifacts that are typically associated with TEM sample preparations, and allows us to investigate the "true" structure and texture of a very large area of the film and at the same time to focus at will on each individual zeolite crystal in the film. Abundant TEM information including crystallographic orientation relationships among crystals in the film (both out-of-plane and in-plane), grain boundaries, and each crystal grain was obtained. This TEM investigation provides direct unambiguous new evidence to support the homogeneous nucleation mechanism, by which the films form through homogeneous nucleation and crystal growth in the bulk to form equal-sized disk-shape crystals, followed by self-assembly of these crystals onto the substrate to produce a two-dimensional close-packed structure. The last stage of the film formation involves simultaneous space-limited growth and rotation of the individual crystals to realize the in-plane crystallographic control within the film.

Journal Article↗

PubMed2004

Molecular sieving in a nanoporous b-oriented pure-silica-zeolite MFI monocrystal film.

The molecular sieving property of a continuous b-oriented pure-silica-zeolite (PSZ) MFI monocrystal film was demonstrated in a zeolite-modified electrode (ZME) configuration using redox molecules of different sizes. Ru(NH3)63+ (diameter approximately 5.5 A) was able to traverse the film, while Co(phen)32+ (diameter approximately 13.0 A) was completely excluded. This film has excellent adhesion to the electrode and is stable in strong acidic conditions.

Journal Article↗

PubMed2004

Ciliary neurotrophic factor for acceleration of peripheral nerve regeneration: an experimental study.

The objective of this study was to investigate the effect of topically administrated ciliary neurotrophic factor (CNTF) on peripheral nerve regeneration. Sixty-eight Sprague Dawley rats underwent a unilateral sciatic nerve transection and silicon tubulization, with a 10-mm gap between the proximal and distal nerve stumps. Recombinant human CNTF (1 mg/kg) was injected into the rats of the experimental group, while normal saline was injected into the control group animals. Electrophysiologic and histologic studies, including nerve morphometry and electron microscopic observation, were performed at 1, 3, and 4 months postoperatively. HRP tracing was carried out at 3 months postoperatively to label spinal-cord, ventral-horn, and dorsal-root ganglia. The results revealed that CNTF-treated animals showed a higher motor nerve conduction velocity of the sciatic nerve and a higher muscle action potential amplitude of the anterior tibial muscle, compared to the controls ( p < 0.01). Nerves repaired with CNTF had larger axon diameter, greater number of axons, and more advanced myelination ( p < 0.05). More HRP-labeled motor neurons were also found in the ventral horns of CNTF-treated animals. These results indicate that topical application of CNTF to the injury site potentiates motor nerve axonal regrowth and axon maturation during peripheral nerve regeneration.

Action Potentials↗

PubMed2003

Longitudinally implanted intrafascicular electrodes for stimulating and recording fascicular physioelectrical signals in the sciatic nerve of rabbits.

The purpose of this experiment was to determine the stimulating and recording characters of fascicular physioelectrical signals in the activity of peripheral nerves by longitudinally implanted intrafascicular electrodes (LIFEs) in a rabbit sciatic nerve model, and discuss the future application of LIFEs in functional electrical stimulation (FES) and control of electric arm prosthesis. In methodology, LIFEs were inserted into the fasciculus of the sciatic nerves of rabbits and used as recording electrodes and stimulating electrodes, respectively. Motor-evoked potentials (MEPs), cortical somatosensory-evoked potentials (CSEPs), and electromyography (EMG) were recorded by using a transcranial stimulation system (TCS). LIFEs were found to have stable stimulating and recording characters. The interpeak amplitudes (IPAs) of MEPs ranged from 78-156 microV (mean +/- SD, 102 +/- 23.2 microV). The onset latency (OL) of MEPs ranged from 9.8-11.2 msec (mean +/- SD, 10.8 +/- 0.6 msec). The interpeak amplitudes (IPAs) of CSEPs ranged from 5.8-7.2 microV (mean +/- SD, 6.7 +/- 0.5 microV). The onset latency (OL) of CSEPs ranged from 11.4-14.6 msec (mean +/- SD, 12.8 +/- 1.3 msec). EMGs could be recorded in the gastrocnemius, but could not be recorded in the tibialis anterior muscle. In conclusion, longitudinally implanted intrafascicular electrodes can act as intrafascicular stimulating and recording electrodes with high selective characters. They can provide a new way to study fascicular physioelectrical signals and their function in the activity of peripheral nerves.

Animals↗

PubMed2003

Enhancement of rat sciatic nerve regeneration by fibronectin and laminin through a silicone chamber.

In this study, the authors examined the effects of fibronectin and laminin on sciatic nerve regeneration in rats. Sixty-eight Sprague-Dawley rats underwent bilateral sciatic nerve transections and silicone tubulizations, with a 10-mm gap between the proximal and distal nerve stumps. Thirty rats (n=30) received 10 microg of fibronectin injection into the right sciatic nerve chamber, while saline was injected into the left nerve chamber, serving as the control. Another 30 rats (n=30) were given 6 microg of laminin injection into the right nerve chambers and saline into the left chambers. At 1, 3, and 4 months postoperatively, electrophysiologic and histologic examinations, including nerve morphometry, were performed. Eight additional rats, receiving fibronectin (n=4) and laminin (n=4) injections, were used for horseradish peroxidase (HRP) tracing at 3 months postoperatively. Results from the study showed that fibronectin- and laminin-treated groups had significantly higher motor nerve conduction velocity and evoked muscle action potential amplitude of the anterior tibial muscle than the control group (p<0.01). Nerve diameter and the number of myelinated axons from the groups receiving fibronectin and laminin applications were greater than the controls (p<0.01). Also, a greater number of HRP-labeled motor neurons were found in the ventral horns and dorsal root ganglia of the fibronectin- and laminin-treatment groups compared to the controls. The authors conclude that local applications of fibronectin and laminin into the nerve chambers can significantly improve axonal regeneration and maturation of injured rat sciatic nerves.

Action Potentials↗

PubMed2002

Photoinduced electron transfer from the excited J-aggregate state of a thiacarbocyanine dye to TiO2 colloids.

The photophysical properties of the J-aggregate of 3,3'-di(3-sulfopropyl)-4,5,4',5'-dibenzo-9-phenyl-thiacarbocyanine triethyl-ammonium salt in the absence and presence of TiO(2) colloids have been studied using UV-visible absorption spectroscopy, steady-state and time-resolved fluorescence spectroscopy, and ESR spectroscopy. The fluorescence emission of the J-aggregate decreases with increasing concentration of TiO(2) colloids. The average fluorescence lifetime of the J-aggregate in the presence of TiO(2) colloids is shorter than that in the absence of TiO(2) colloids. A strong photoinduced ESR signal has been observed during illumination by light with lambda=633 nm in the presence of TiO(2) and the ESR signal can be attributed to the J-aggregate radical cation. From the above results, it is concluded that photoinduced electron transfer from the excited singlet state of the J-aggregate to the conduction band of TiO(2) takes place and the electron transfer rate is about 1.5 x 10(8) s(-1).

Journal Article↗

PubMed2002

Recombinant human heparin-binding neurite-promoting factor expressed with yeast stimulates neurites outgrowth.

OBJECTIVES: Heparin-binding neurite-promoting factor (HBNF) is a heparin-binding protein primarily found in the brain, which can stimulate neurite outgrowth in vitro. We expressed recombinant human heparin-binding neurite-promoting factor (hrHBNF) using a yeast system, and observed its activity in stimulating neurite outgrowth in vitro. METHODS: cDNA encoding mature human HBNF was amplified from total RNA isolated from an 18-week aborted human fetal brain by RT-PCR method. After amplification, the HBNF cDNA gene was cloned into pPIC9K, a shuttle expression vector for yeast system. The positive clone of expression vector bearing HBNF cDNA gene was obtained by screening. Verified recombinant vector was then used to transform Pichia strain GS115 by electroporation. His(+) transformants were selected on minimal dextrose medium (MD) plates which were histidine free. His(+) yeast recombinants with multi-copy inserts were screened in vivo by their resistance to G418. PCR analysis was used to confirm the integration of the HBNF cDNA gene into the Pichia genome. Secreted expression of hrHBNF protein in culture medium was obtained when the positive clone containing the HBNF cDNA gene was induced by methanol. The hrHBNF product purified by gel chromatography was added to cultured rat pheochromocytoma (PC12) cells to observe its ability to stimulate neurite outgrowth. RESULTS: In the recombinant expression vector, the insert was sequenced to show exactly the sequence encoding human HBNF according to Genbank data. The HBNF cDNA gene was cloned downstream to the alpha-factor, and its open reading frame was in frame with the alpha-factor signal sequence in pPIC9K. SDS-PAGE showed that the molecular weight of the induced expression product was about 18 kDa, consistent with that of human HBNF reported in the literature. The protein product did promote neurite outgrowth in cultured rat pheochromocytoma (PC12) cells. CONCLUSION: Recombinant human heparin-binding neurite-promoting factor can be expressed with a yeast system, and its product possesses the biological activity to promote neurite outgrowth.

Animals↗

PubMed2002

A clinicopathologic and immunohistochemical study of diffuse large B-cell lymphoma.

OBJECTIVE: To study the clinicopathologic and immunohistochemical features of diffuse large B-cell lymphoma (DLBCL) and the significance of immunohistochemistry in diagnosis and differential diagnosis of DLBCL. METHODS: 60 cases of DLBCL were studied and immunohistochemical staining for LCA, L26, BLA-36, CD30, bcl-6 were carried out with the EnVision 2 step method. RESULTS: The age range of 76.7% (46/60) patients was 40 - 70 years. The location of the lesion includes nodal and extranodal sites. 90.0% (54/60) were in clinical stages of II (24/54), III (21/54), IV (9/54). Histopathologic morphology presented as centroblastic (88.3%, 53/60), immunoblastic (3.3%, 2/60), anaplastic large B cell type (3.3%, 2/60) and T cell rich B cell type (5.0%, 3/60). Immunostaining showed 100% (60/60) DLBCL were positive for LCA, L26, BLA36, 3.3% (2/60) DLBCL positive for CD30, 95% (57/60) expressed bcl-6 protein. CONCLUSIONS: DLBCL is an aggressive lymphoma which shows cytologic variability from case to case. The evaluation of pathologic features and immunohistochemistry in DLBCL are useful and practical for diagnostic purposes, but cannot delineate distinctive morphologic subtypes.

Adult↗

PubMed2000

Modulation of nitric oxide synthase isoenzymes in reperfused skeletal muscle.

OBJECTIVE: To investigate the modulation of nitric oxide synthase (NOS) isoenzymes in skeletal muscle during 3 h ischemia/reperfusion (I/R, 3 h ischemia followed by 3 h reperfusion). METHODS: The extensor digitorum longuses (EDLs) from 20 adult rats were divided into 4 groups: the normal, the sham operation, the ischemia (3 h), and the ischemia/reperfusion group. One normal EDL from each rat was used as the non-operated control, and the opposite ones are distributed into the 3 remaining groups. All the samples were studied with Western blotting technique and immunohistochemistry staining. RESULTS: Three sizes of protein bands verified with the proteins of relative molecule to be of 155000, 140000 and 135000, were detected in the EDL homogenate by Western blotting, which were comparable with the positive controls for nNOS, eNOS and iNOS, respectively. Immunostaining demonstrated that nNOS was present in the muscle fiber, with a similar location of the muscle stria, eNOS was found apparently in microvascular endothelia, but not found in muscle fibers, and iNOS was found in the leukocytes around the muscle fiber and some endothelia cells. Immunostaining paralleled the Western blotting results. CONCLUSIONS: It suggests that the constitutive nNOS and eNOS protein can be regulated by I/R, and I/R results in a down regulation of nNOS and up-regulation of eNOS and iNOS in reperfused skeletal muscle. The fact that nNOS is present around stria suggests that nNOS may have a close relationship with muscle function. The localization of eNOS in endothelial cell indicates its role in regulating blood supply of the muscle. Based on these findings, it is possible that NO produced by distinct NOS may play a different role in I/R injury.

Journal Article↗

PubMed2000

Electronic artificial hand controlled by reconstructed digit.

OBJECTIVE: To treat the loss of part of the forearm with a multi-dimension-freedom electronic artificial hand, which is controlled by a reconstructed finger transplanted from the second toe to the forearm stump. METHODS: The female patient was 19 years old, whose right hand and wrist were crushed into pieces by machine at work and her forearm was amputated at the level of 8 cm proximal to the wrist. The second toe of her left foot was transplanted to reconstruct the digit onto the stump of her forearm. Two months after the transplantation, the patient was transferred to the rehabilitation center for further rehabilitation training, which consisted of: training for adaptation to weight bearing, testing and training of sensibility to weight. testing and training for stability of the hand, and testing and training for the controlling function of the reconstructed digit. RESULTS: The transplanted toe survived well. After rehabilitation the reconstructed digit functioned well. In testing the performance under control mandate, the accuracy rate of the electronic artificial hand was 100%. CONCLUSIONS: A 100% accuracy rate of the electronic artificial hand can be achieved by transplantation of the toe onto the stump of the forearm. It provides a useful pathway and an example for improvement of control accuracy of a multiple-freedom electronic artificial hand and reduction of false action.

Journal Article↗