Biomedical subjects

Chun-Yu Lin

Publications and source records attributed to Chun-Yu Lin.

13 recordsLinked to original sources

PubMed2006

Case report: infective endocarditis caused by Brevundimonas vesicularis.

BACKGROUND: There are few reports in the literature of invasive infection caused by Brevundimonas vesicularis in patients without immunosuppression or other predisposing factors. The choice of antimicrobial therapy for bacteremia caused by the pathogen requires more case experience to be determined. CASE PRESENTATION: The case of a 40-year-old previously healthy man with subacute endocarditis proposed to be contributed from an occult dental abscess is described. The infection was found to be caused by B. vesicularis on blood culture results. The patient recovered without sequelae after treatment with ceftriaxone followed by subsequent ciprofloxacin therapy owing to an allergic reaction to ceftriaxone and treatment failure with ampicillin/sulbactam. CONCLUSION: To our knowledge, this is the first report of B. vesicularis as a cause of infective endocarditis. According to an overview of the literature and our experience, we suggest that third-generation cephalosporins, piperacillin/tazobactam, and ciprofloxacin are effective in treating invasive B. vesicularis infections, while the efficacy of ampicillin-sulbactam needs further evaluation.

Adult↗

PubMed2006

The apoptotic effect of cordycepin on human OEC-M1 oral cancer cell line.

Cordycepin (3'-deoxyadenosine), a pure compound of Cordyceps sinensis, has been illustrated with anti-tumor effects. In the present study, the apoptotic effect of cordycepin on OEC-M1, a human oral squamous cancer cell line, was investigated by morphological observations, cell viability assay, annexin V-FITC analysis and flow cytometry methods. Results demonstrated that the number of rounded-up cell increased as treatment duration of cordycepin (100 microM) increased from 3 to 48 h, and the plasma membrane blebbing could be observed after 12 h treatment. In cell viability assay, cell surviving rate significantly decreased as the dosage and duration of cordycepin treatment increased (P < 0.05). Moreover, phosphatidylserine flipping on cell membrane could be detected with 3, 6 and 12 h cordycepin treatment, which indicated an early apoptotic phenomenon. Furthermore, cell cycle studies illustrated that the percentage of G1 phase cell declined as the dosages of cordycepin increased (10 microM to 5 mM), while the percentages of G2M and subG1 phase cell increased (P < 0.05) in 12, 24 and 48 h cordycepin treatment. These results further confirmed the apoptotic event. In conclusion, cordycepin significantly induced cell apoptotsis in OEC-M1 human oral squamous cancer cells.

Antineoplastic Agents↗

PubMed2006

Precise determination of the dielectric constant and thickness of a nanolayer by use of surface plasmon resonance sensing and multiexperiment linear data analysis.

Surface plasmon resonance (SPR) sensing and an enhanced data analysis technique are used to obtain precise predictions of the dielectric constant and thickness of a nanolayer. In the proposed approach, a modified analytical method is used to obtain initial estimates of the dielectric constants and thicknesses of the metal film and a nanolayer on the sensing surface of a SPR sensor. A multiexperiment data analysis approach based on a two-solvent SPR method is then employed to improve the initial estimates by suppressing the noise in the measurement data. The proposed two-stage approach is employed to determine the dielectric constant and thickness of a molecular imprinting polymer nanolayer. It is found that the results are in good agreement with those obtained with an ellipsometer and a high-resolution scanning electron microscope.

Journal Article↗

PubMed2006

Cloning and characterization of a shrimp clip domain serine protease homolog (c-SPH) as a cell adhesion molecule.

Clip domain serine protease homologs (c-SPHs) are involved in various innate immune functions in arthropods such as antimicrobial activity, cell adhesion, pattern recognition, opsonization, and regulation of the prophenoloxidase system. In the present study, we cloned a c-SPH cDNA from tiger shrimp (Penaeus monodon) hemocytes. It is 1337 bp in length with a coding region of 1068 bp consisting a protein of 355 amino acid residues. The deduced protein includes one clip domain and one catalytically inactive serine protease-like (SP-like) domain. Its molecular weight is estimated to be 38 kDa with an isoelectric point of 7.9. The predicted cutting site of the signal peptide is located between Gly(21) and Gln(22). We aligned 15 single clip domain SPH protein sequences from 12 arthropod species; the identity of these clip domains is low and that of SP-like domains is from 34% to 46%. The conserved regions are located near the amino acid residues which served as substrate interaction sites in catalytically active serine protease. Phylogenetically, the tiger shrimp c-SPH is most similar to a low molecular mass masquerade-like protein of crayfish, but less similar to c-SPHs in Chelicerata and Insecta. Nested reverse transcription polymerase chain reaction (RT-PCR) revealed that c-SPH mRNA is expressed most in tissues with the highest hemocyte abundance. Antimicrobial and opsonization activities of the molecule were not detected. The expression of c-SPH mRNA in hemocytes was up-regulated at the 12-day post beta-glucan immersion. Recombinant c-SPH could significantly enhance hemocyte adhesion. The result suggests that the shrimp c-SPH protein plays a role in innate immunity.

Amino Acid Sequence↗

PubMed2006

Optical waveguide biosensors constructed with subwavelength gratings.

The reflection resonance spectrum of a subwavelength diffraction-grating-coupled waveguide is used to analyze biomolecular interactions in real time. By detecting this resonance wavelength shift, the optical waveguide biosensor provides the ability to identify the kinetics of the biomolecular interaction on an on-line basis without the need for extrinsic labeling of the biomolecules. A theoretical analysis of the subwavelength optical waveguide biosensor is performed. A biosensor with a narrow reflection resonance spectrum, and hence an enhanced detection resolution, is then designed and fabricated. Currently, the detection limit of the optical waveguide sensor is approximately 10(-5) refractive-index units. The biosensor is successfully applied to study of the dynamic response of an antibody interaction with protein G adsorbed on the sensing surface.

Biosensing Techniques↗

PubMed2005

The remediation of hearing deterioration in children with large vestibular aqueduct syndrome.

Based on imaging findings, large vestibular aqueduct syndrome (LVAS) in early childhood is the most common cause of sensorineural hearing loss. Children with LVAS are at a high risk of suffering sudden deteriorations in hearing. This study was to review treatment of sudden hearing deterioration in children with LVAS who underwent corticosteroid therapy. We conducted a retrospective study of patients presenting to an academic tertiary medical center. Sixteen children of LVAS were evaluated. Corticosteroid therapy (prednisolone 1-2 mg/(kg day) or equal titer's dexamethasone) was administered as soon as sudden hearing loss developed. The pure tone audiometric result improved more than 10dB at two or more consecutive frequencies and was regarded as a significant response to corticosteroid therapy. Sixteen cases comprising 12 boys and 4 girls were retrospectively analyzed in this study. The mean age at which LVAS was diagnosed was 2.3 years. Mean follow-up for the 16 cases from the first clinic visit to November 2003 was 4.2 years. The initial audiograms varied from down-sloping, valve or rising patterns. In addition, bilateral enlargement of the vestibular aqueduct was found to all children and the mean diameter of right and left ears were 7.23 and 6.83 mm, respectively. Seven children had totally experienced 13 episodes of sudden hearing deterioration. After receiving corticosteroid therapy in time, 11 of 13 episodes had indicated significant responses to treatment, a response rate of 85%. Early detection of LVAS and the timing of treatment are crucial for preventing the residual hearing from deteriorating. As soon as the hearing deterioration of a child with LVAS is recognized, aggressive intervention such as corticosteroid therapy should be performed in no time.

Audiometry, Pure-Tone↗

PubMed2004

A method for direct thalamic stimulation in fMRI studies using a glass-coated carbon fiber electrode.

Recent fMRI studies are of interest in exploring long-range interactions between different brain structures and the functional activation of specific brain regions by known neuroanatomical pathways. One of the experimental approaches requires the invasive implantation of an intracranial electrode to excite specific brain structures. In the present report, we describe a procedure for the production of a glass-coated carbon fiber electrode and the use of this electrode for direct activation of the brain in fMRI studies. The glass-coated carbon fiber microelectrode was implanted in the medial thalamus of anaesthetized rats and T2*-weighted gradient echo images in the sagittal plane obtained on a 4.7 T system (Biospec BMT 47/40) during electrical stimulation of the medial thalamus. The image quality obtained using this electrode was acceptable without reduction of the signal-to-noise ratio and image distortion. Cross-correlation analysis showed that the signal intensities of activated areas in the ipsilateral anterior cingulate cortex were significantly increased by about 4-5% during medial thalamus stimulation. The present study shows that glass-coated carbon fiber electrodes are suitable for fMRI studies and can be used to investigate functional thalamocingulate activation.

Animals↗

PubMed2004

BOLD response to direct thalamic stimulation reveals a functional connection between the medial thalamus and the anterior cingulate cortex in the rat.

Recent functional neuroimaging studies in humans and rodents have shown that the anterior cingulate cortex (ACC) is activated by painful stimuli, and plays an important role in the affective aspect of pain sensation. The aim of the present study was to develop a suitable stimulation method for direct activation of the brain in fMRI studies and to investigate the functional connectivity in the thalamo-cingulate pathway. In the first part of the study, tungsten, stainless steel, or glass-coated carbon fiber microelectrodes were implanted in the left medial thalamus (MT) of anesthetized rats, and T2*-weighted gradient-echo (GE) images were obtained in the sagittal plane on a 4.7 T system (Biospec BMT 47/40). Only the images obtained with the carbon fiber electrode were acceptable without a reduction of the signal-to-noise ratio (SNR) and image distortion. In the second part of the study, a series of two-slice GE images were acquired during electrical stimulation of the MT with the use of a carbon fiber electrode. A cross-correlation analysis showed that the signal intensities of activated areas in the ipsilateral ACC were significantly increased by about 4.5% during MT stimulation. Functional activation, as assessed by the distribution of c-Fos immunoreactivity, showed strong c-Fos expression in neurons in the ipsilateral ACC. The present study shows that glass-coated carbon fiber electrodes are suitable for fMRI studies and can be used to investigate functional thalamocortical activation.

Animals↗

PubMed2004

Community-based newborn hearing screening program in Taiwan.

OBJECTIVE: Congenital bilateral hearing impairment occurs in approximately 1 in every 1000 live births. Universal newborn hearing screening (UNHS) programs are the most effective method for early diagnosis. Previously, newborn hearing screenings in Taiwan were often hospital-based. Our study is a community-based program designed to test the feasibility of performing neonatal hearing screening with a pay-for-test model, and to evaluate its acceptability to parents. METHODS: From March 2000 to December 2002, two hospitals and four obstetric clinics in Tainan city participated in this study. The subjects were healthy newborns whose parents agreed to pay for otoacoustic emissions (OAE) hearing screening. They were tested in the newborn nursery before discharge. The protocol used an initial transient evoked otoacoustic emissions screening followed by a diagnostic auditory brainstem response (ABR) test. RESULTS: A total of 10,008 healthy neonates were recruited, and 5938 newborns (59.3%) were tested. Prior to hospital discharge, 5403 of the newborns (91.0%) had passed the transient evoked otoacoustic emissions test. Referral for further testing was made in 9.0% of cases (535/5938). There were 140 babies lost to 1-month follow up. Only 395 infants (73.8%) of the infants that failed their first otoacoustic emissions tests underwent a second session at the outpatient clinic, and 91 babies failed. They were referred for further auditory brainstem response testing. Ultimately, nine babies were diagnosed with sensorineural hearing loss (SNHL). CONCLUSIONS: There are difficulties in performing universal newborn hearing screening within Taiwan's health insurance system. This study was performed with the cooperation of hospitals and obstetric clinics, and was undertaken with a pay-for-screening model. Our program, with a pay-for-test model, of newborn hearing screening is feasible and was well regarded by parents in Tainan city. It could be run without the government's financial support.

Community Health Services↗

PubMed2004

Mucosal changes in rhinitis medicamentosa.

To evaluate the nasal mucosal changes in rhinitis medicamentosa (RM), especially those related to goblet cells and subepithelial glands, we studied specimens of the inferior turbinate mucosa from 8 patients with RM, 8 patients with chronic hypertrophic rhinitis (CHR), and 5 patients with normal nasal mucosa. All specimens were assessed by electron microscopy and immunohistochemical study. Under a scanning electron microscope, hyperplasia of goblet cells was most prominent in the RM group, and an increased number of gland openings was evident in the RM and CHR groups. In addition, the immunoreactivity of epidermal growth factor receptor staining was strongest in the hyperplastic epithelium of the RM group. According to our results, it is feasible that the mucosa of patients with RM is in a chronic inflammatory, hypersecretory state. Degenerative changes in the secretory elements may cause impairment of mucociliary transport and may be responsible for the nasal obstruction and posterior nasal drip in RM.

Case-Control Studies↗

PubMed2003

The effect of Gu-Sui-Bu (Drynaria fortunei J. Sm) immobilized modified calcium hydrogenphosphate on bone cell activities.

In our previous study, we have validated the efficacy and the safety of Gu-Sui-Bu [Drynaria fortunei (Kunze) J. Sm.] by the bone cells culture. However, a satisfactory delivery system for Gu-Sui-Bu must be developed before it can be used in clinical medicine. In this study, we try to use modified calcium hydrogenphosphate (MCHP) bioceramic as a carrier to transport Gu-Sui-Bu into the bone cell culture system. Toward this goal, we evaluated the effect of a Gu-Sui-Bu-immobilized modified calcium hydrogenphosphate (GI-MCHP) on the bone cells activities. THE CHINESE MEDICINE: Gu-Sui-Bu [Drynaria fortunei (kunze) J. Sm] was extracted and then immobilized on the surface of MCHP. The rat osteoblasts-osteoclasts co-culture system was used as the experimental model. After the cells grew to 80% confluence, different sizes of GI-MCHP particles were tested. The mitochondria activity of the bone cells after exposure was determined by colorimetric assay. Biochemical markers such as lactate dehydrogenase (LDH), alkaline phosphatase (ALP), acid phosphatase (ACP) and prostaglandin E(2) titer were analyzed to evaluate the bone cells activities. Histomorphometric study of osteoclasts activities and the phenotype expression of osteoblasts were also evaluated. There is no detectable titer of LDH secretion into the medium and no significant change in the intracellular ALP content. The ALP titer in the culture medium did increase significantly at 3 days' culture, while there is a significant decrease in the intracellular ACP content and significant increase in the ACP titer in the medium. The concentrations of PGE(2) in tested medium are always significantly higher than that of control medium during the 7 days' culture. At the end of 7 days' culture, the PGE(2) concentrations in the tested medium were still 4.74 times that of the control medium. After GI-MCHP treatment on bone cells, the size of the osteoclasts seems decreased and their cell integrity seems lost, while the osteoblasts phenotype expression was relatively preserved. From this study, we demonstrated that Gu-Sui-Bu [Drynaria fortunei (Kunze) J. Sm.] immobilized MCHP has well preserved the potential beneficial effects of Gu-Sui-Bu on the bone cells culture.

Alkaline Phosphatase↗

PubMed2002

The effect of Gu-Sui-Bu (Drynaria fortunei J. Sm) on bone cell activities.

In the traditional Chinese medicine, Gu-Sui-Bu [Drynaria fortunei (kunze) J. Sm] has been reported as a good enhancer for bone healing. In this experiment, we investigate the biochemical effects of this traditional Chinese medicine on the bone cells culture. Different concentrations of crude extract of Gu-Sui-Bu were added to rat bone cells culture. The mitochondria activity of the bone cells after exposure was determined by colorimetric assay. Biochemical markers such as alkaline phosphatase (ALP), acid phosphatase (ACP) titer, prostaglandin E2 (PGE2) titer and the expression of both osteopontin and osteonectin mRNA were evaluated. The effect on the osteoclasts differentiation was evaluated by tartrate-resistant acid phosphatase (TRAP) stain. The most effective concentration of Gu-Sui-Bu on bone cells was 1 mg/ml. The addition of 1 mg/ml Gu-Sui-Bu to bone cells culture for 7 days can statistically increase the intracellular ALP amount; while the ACP and PGE2 amount in culture medium were significantly increased. In Northern blot analysis, the expression of both osteopontin and osteonectin mRNA were down-regulated after adding Gu-Sui-Bu into bone cells culture. The formation of multi-nucleated osteoclasts was more active than that of the control group, but no giant osteoclasts formation was observed. In this study, we demonstrated that Gu-Sui-Bu has potential effects on the bone cells culture. One of the major effects of Gu-Sui-Bu on the bone cells is probably mediated by its effect on the osteclasts activities. Continued and advanced study on the alterations in gene expression of bone cells by Chinese medicines will provide a basis for understanding the observed bone cell responses to various pharmacological interventions.

Acid Phosphatase↗

PubMedDate not supplied

Reactive oxygen scavenger effect of pyrimidines, benzotriazoles and related compounds.

Free radicals and reactive oxygen metabolites have been implicated as important pathologic mediators in many clinical disorders and diseases. An efficient method of detecting the free radical scavenger effect is through xanthine oxidase (XO) inhibition. The inhibition efficiency on XO has been detected as the rate of uric acid production, which has max 295 nm. Sulfasalazine showed potent inhibiting activity on XO (IC50 = 25.11 microM; Ki = 50.88 microM) and induced a mixed-type (non-competitive-uncompetitive) inhibition of the substrate xanthine. 2-mercapto-4(3H)-quinazolinone (16) and 2-mercaptopyrimidine (4) displayed inhibiting activity on XO with IC50 = 98.71 and 136.14 microM, while apparent inhibition constants (Ki) were 158.38 and 62.46 microM, respectively. However benzotriazoles showed weak inhibitory effect. The spin-trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) by electron spin resonance (ESR) detected the presence of O2-* and OH*. It showed that the percentage inhibition for formation of DMPO-OOH for 2-mercapto-pyrimidine and sulfasalazine were 64.78 and 35.09, but for hydroxylation were 49.51, 38.55, 37.29 for 2-mercapto-4(3H)-quinazolinone, sulfasalazine and 2-mercaptopyrimidine at 500 microM, respectively.

Electron Spin Resonance Spectroscopy↗