Biomedical subjects

Hsiung-Fei Chien

Publications and source records attributed to Hsiung-Fei Chien.

7 recordsLinked to original sources

PubMed2006

Myxoid solitary fibrous tumour of the axilla.

Mostly occurring in pleura, solitary fibrous tumour is an unusual soft tissue neoplasm. Solitary Fibrous Tumour with abundant myxoid stroma represents a rare morphologic subtype of the already uncommon tumour. We report a myxoid solitary fibrous tumour of the soft tissue in a 42-year-old man. The patient presented with a large, movable, nontender mass at the right axilla. The MRI showed a well-defined tumour with increased signal after gadolinium injection. During surgery, the mass was found to be closely associated with the axillary vein. The tumour was completely excised. Pathological and immunohistochemical examinations identified the mass as a myxoid solitary fibrous tumour. The patient was free of tumour recurrence at 18-month follow-up. The rare tumour in an uncommon location makes the diagnosis difficult. Complete excision and long-term follow up are recommended.

Adult↗

PubMed2005

Responses of microglia in vitro to the gram-positive bacterial component, lipoteichoic acid.

An increase in incidence and severity of gram-positive infections has emerged in the past decade. In this regard, attention has been focused recently on immune responses of microglial cells in the central nervous system to gram-positive bacteria. The underlying immunological and cellular events in microglial activation induced by specific bacterial toxin of gram-positive bacteria, however, have not yet been clarified fully. This study reports that a simple cell wall product, lipoteichoic acid (LTA), derived from gram-positive bacteria (Staphylococcus aureus) could trigger microglial activation in vitro. Microglia challenged with LTA showed intense ruffling of plasma membrane in the form of lamellipodia or rounded up forming cell aggregates. MTT assay and Western blot analysis with anti-proliferating cell nuclear antigen antibody showed a significant microglial proliferation that may be induced at the later phases of LTA treatment with low doses but at the early period with a high dose. Concentrated LTA also caused apoptotic death of cultured microglia showing fragmented nuclei and increased expression of annexin V or caspase 3. In response to LTA, isolated microglia increased the expression of inducible nitric oxide synthase and major histocompatibility complex class II antigen. Microglial LTA receptors such as CD14 molecule, complement receptor type 3, and macrophage scavenger receptor were upregulated concurrently. In conclusion, staphylococcal LTA can exert an immunomodulatory effect on microglial morphology, cell cycle, and immunomolecules, including its receptors.

Animals↗

PubMed2005

Multiple negative feedbacks on CD152 expression in allograft tolerance.

BACKGROUND: CD152 has been implicated in tolerance induction. This study investigated how CD80 and CD86 regulated CD152 expression in a low-responding cardiac transplant model with CD152-mediated long-term graft acceptance. METHODS: A low-responding cardiac transplant model from BALB/c to B10.A was used. Donor-specific stimulation and multiple antibody blockade of the CD80/CD86:CD28/CD152 co-stimulatory pathway was applied to the splenic T cells from B10.A recipients with 100-day grafts (B10.A-100). Proliferation assays, quantitative (Q) real-time polymerase chain reaction (PCR), flow cytometric analyses, and fluorescence microscopy were conducted to examine the roles of CD80 and CD86 in CD152 expression. RESULTS: B10.A-100 splenic T cells were hyporesponsive to donor-specific stimulation, and anti-CD80, anti-CD86, or anti-CD152 treatment significantly enhanced the proliferation response of the B10.A-100 splenic T cells. Proliferation assays and Q-PCR revealed that CD152 inhibited T-cell proliferation and, at the same time, decreased CD152 expression by secluding CD80 and CD86 from CD28 engagement. Flow cytometric analyses and fluorescence microscopy showed that CD28 engagement facilitated intracellular accumulation of CD152. Besides, CD152 engagement by CD80 decreased CD152 mRNA transcription, and CD152 engagement by CD86 inhibited surface expression of CD152. CONCLUSIONS: CD80 and CD86 controlled CD152-mediated allograft tolerance by multiple negative feedbacks on CD152 mRNA and surface expression.

Animals↗

PubMed2005

Reorganization of cytoskeleton induced by 5-aminolevulinic acid-mediated photodynamic therapy and its correlation with mitochondrial dysfunction.

BACKGROUND AND OBJECTIVES: This study investigated the early cellular events which occurred after mitochondrial photodamage induced by 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT). STUDY DESIGN/MATERIALS AND METHODS: Subcellular localization of protoporphyrin IX (PpIX) in NIH3T3 cells was studied by confocal microscopy. Mitochondrial damage was assessed by measuring mitochondrial transmembrane potential and ATP contents, and confirmed by characteristic appearance on transmission electron microscopy. Cellular adhesion was measured by the level of resistance to trypsinization. Cytoskeletal studies were performed by fluorescent staining of cytoskeletal components. RESULTS: Following ALA-PDT, mitochondrial damage was found in NIH3T3 cells as judged by the decrease of membrane potential and ATP contents. Mitochondrial photodamage was further confirmed by electron microscopy. Resistance to trypsinization after ALA-PDT was shown to be light dose-dependent. The increase of cellular adhesion after ALA-PDT was correlated with mitochondrial photodamage and reorganization of cytoskeletal components in NIH3T3 cells. CONCLUSIONS: This study has demonstrated that mitochondrial dysfunctions induced by ALA-PDT results in alterations of cellular morphology and cellular adhesion.

Acid Phosphatase↗

PubMed2005

Skin denervation, neuropathology, and neuropathic pain in a laser-induced focal neuropathy.

Small-diameter sensory nerves innervating the skin are responsive to noxious stimuli, and an injury to these nerves is presumably related to neuropathic pain. Injury-induced neuropathic pain in animals can be produced by laser irradiation, which usually requires concomitant use of photosensitive dyes, known as the photochemical approach. It is not clear whether laser irradiation alone can induce neuropathic pain. In addition, two issues are important to apply these approaches: the relationship between the extent of laser irradiation and the occurrence of neuropathic pain, and the susceptibility of small-diameter sensory nerves in the skin to laser-induced neuropathic pain. To address these issues, we designed a new model of focal neuropathy by applying a diode laser of 532 nm (100 mW) to the sciatic nerve and evaluated small-diameter nerves by quantifying skin innervation and large-diameter nerves by measuring amplitudes of the compound muscle action potential (CMAP). Immediately after laser irradiation, epineurial vessels were occluded due to the formation of thrombi, and the blood flow through these vessels was markedly reduced. On postoperative day (POD) 2, animals developed characteristic manifestations of neuropathic pain, including spontaneous pain behaviors, thermal hyperalgesia, and mechanical allodynia. These phenomena peaked during PODs 7-21, and lasted for 3-6 weeks. The neuropathology at the irradiated site of the sciatic nerve included a focal area of axonal degeneration surrounded by demyelination and endoneurial edema. The extent of damage to large-diameter motor and sensory nerves after laser irradiation was evaluated by nerve conduction studies. On the irradiated sides, amplitudes of the compound muscle action potentials and sensory nerve action potentials (SNAPs) were reduced to 65.0% (P < 0.0001) and 42.5% (P < 0.01) of those on the control sides, respectively. Motor innervation of the neuromuscular junctions (NMJs) on plantar muscles was examined by combined cholinesterase histochemistry and immunohistochemistry. The ratio of innervated NMJs on the operated sides decreased to 76.3% of that on the control side. Skin innervation in the territory of the irradiated sciatic nerves was evaluated by immunohistochemistry with neuronal markers. Among these markers, epidermal nerve densities for protein gene product (PGP) 9.5, calcitonin gene-related peptide (CGRP), and substance P (SP) were significantly lower on the irradiated sides than the control sides with a different degree of loss for each marker (42.1-53.1%, P < 0.05). Results suggest that laser-induced focal neuropathy provides a new system for studying neuropathic pain. With this approach, the extent of nerve injury can be quantified. Both small-diameter epidermal nerves and large-diameter sensory and motor nerves are susceptible to laser-induced injury of different degrees.

Animals↗

PubMed2005

Reinnervation of muscular targets by nerve regeneration through guidance conduits.

We established histopathologic and neurophysiologic approaches to examine whether different designs of polycaprolactone-engineered nerve conduits (hollow vs. laminated) could promote nerve regeneration as autologous grafts after transection of sciatic nerves. The assessments included morphometric analysis at the level of sciatic nerve, neuromuscular junction (NMJ) and gastrocnemius muscle, and nerve conduction studies on sciatic nerves. Six months after nerve grafting, the nerve fiber density in the hollow-conduit group was similar to that in the autologous-graft group; the laminated-conduit group only achieved approximately 20% of these values. The consequences of these differences were reflected in nerve growth into muscular targets; this was demonstrated by combined cholinesterase histochemistry for NMJ and immunohistochemistry for nerve fibers innervating NMJ with an axonal marker, protein gene product 9.5. Hollow conduits had similar index of NMJ innervation as autologous grafts; the values were higher than those of laminated conduits. Among the 3 groups there were same patterns of differences in the cross-sectional area of muscle fibers and amplitudes of compound muscle action potential. These results indicate that hollow conduits were as efficient as autologous grafts to facilitate nerve regeneration, and provide a multidisciplinary approach to quantitatively evaluate muscular reinnervation after nerve injury.

Action Potentials↗

PubMed2004

The role of B7 ligands (CD80 and CD86) in CD152-mediated allograft tolerance: a crosscheck hypothesis.

BACKGROUND: The regulatory mechanism by which the B7 ligands (CD80 and CD86) direct the CD28/CD152 costimulatory pathways is unclear. This study investigated the role of CD80 and CD86 in a CD152-mediated allograft tolerance model. METHODS: A low-responding cardiac transplant model (BALB/c-->B10.A) with possible long-term acceptance was used. Immunocytochemical and flow cytometric analyses of the graft-infiltrating cells were conducted to characterize this transplant model. The influence of anti-CD80 and anti-CD86 treatments on the proliferation and interleukin (IL)-2 productions of the tolerated splenocytes (SC) was analyzed. The role of CD80 and CD86 in the induction and maintenance of the graft acceptance in this transplant model were also tested. RESULTS: B10.A mice could accept the BALA/c cardiac allografts (11/22), and an anti-CD152 antibody blocked the graft acceptance (10/10). Immunocytochemical and flow cytometric analyses showed that CD152+ cells were predominant among the CD4+ cells infiltrating the 100-day grafts of the B10.A recipients (B10.A-100). Either anti-CD80 or anti-CD86 treatment significantly enhanced polyclonal proliferation and IL-2 production of the B10.A-100 SC. Blockade of either CD80 or CD86 prohibited the tolerance transmitted by adoptive transfer, and anti-CD80 or anti-CD86 plus skin grafting undermined the established allograft tolerance. CONCLUSIONS: Both CD80 and CD86 were essential for the induction and maintenance of the CD152-mediated allograft tolerance.

Adoptive Transfer↗