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Biomedical subjects

S-J Chen

Publications and source records attributed to S-J Chen.

At least 19 recordsLinked to original sources
PubMed2007

Acute renal infarction: a 10-year experience.

The diagnosis of acute renal infarction (ARI) is often delayed or unrecognised because of its non-specific presentation and the rarity of the disease. We evaluated the clinical presentations, laboratory findings, underlying medical conditions and treatment of 18 Chinese patients with ARI who presented to the emergency department (ED) of a tertiary teaching hospital from 1995 to 2004. We identified 14 non-trauma and four trauma patients with ARI. The mean duration from the onset of symptoms to the diagnosis of ARI was 1.9 days. The prevalence of concurrent events was 39%. About 64.5% of non-trauma patients had histories of atrial fibrillation, structural heart diseases or previous embolic events. The laboratory characteristics were neither specific nor sensitive for the diagnosis of ARI. Conservative treatment, local intra-arterial thrombolytic and i.v. thrombolytic therapies were provided in nine, five and two patients respectively. Decreased effective renal plasma flow in affected kidneys was found in three of three patients. Serum creatinine (Cr) was normal or elevated not more than 25% of baseline in 16 cases. ARI may resemble many non-renal diseases; however, repeated evaluation and a high index of suspicion are required for early diagnosis. Concurrent injuries or thromboembolism in other foci should be noticed. Early contrast-enhanced computerized tomography scan should be considered for high-risk patients. Patients with ARI should be followed by functional studies rather than serum Cr level.

Acute Disease↗
PubMed2006

Coupled waveguide-surface plasmon resonance biosensor with subwavelength grating.

This study develops a coupled waveguide-surface plasmon resonance (CWSPR) biosensor with a subwavelength grating structure for the real-time analysis of biomolecular interactions. In the proposed optical metrology system, normally incident white light is coupled into the waveguide layer through the subwavelength grating structure thereby enhancing the wave vector which excites the surface plasmons on the metal sensing surface. The proposed CWSPR biosensor not only retains the same sensing sensitivity as that of a conventional surface plasmon resonance device, but also yields a sharper dip in the reflectivity spectrum and therefore provides an improved measurement precision. Moreover, the metrology setup overcomes the limitations of the conventional Kretschmann attenuated total reflection approach and is less sensitive to slight variations in the angle of the incident light. The experimental results confirm that the current CWSPR biosensor provides a straightforward yet powerful technique for real-time biomolecular interaction analysis.

Biopolymers↗
PubMed2006

Eriocalyxin B induces apoptosis of t(8;21) leukemia cells through NF-kappaB and MAPK signaling pathways and triggers degradation of AML1-ETO oncoprotein in a caspase-3-dependent manner.

Diterpenoids isolated from Labiatae family herbs have strong antitumor activities with low toxicity. In this study, Eriocalyxin B (EriB), a diterpenoid extracted from Isodon eriocalyx, was tested on human leukemia/lymphoma cells and murine leukemia models. Acute myeloid leukemia cell line Kasumi-1 was most sensitive to EriB. Significant apoptosis was observed, concomitant with Bcl-2/Bcl-XL downregulation, mitochondrial instability and caspase-3 activation. AML1-ETO oncoprotein was degraded in parallel to caspase-3 activation. EriB-mediated apoptosis was associated with NF-kappaB inactivation by preventing NF-kappaB nuclear translocation and inducing IkappaBalpha cleavage, and disturbance of MAPK pathway by downregulating ERK1/2 phosphorylation and activating AP-1. Without affecting normal hematopoietic progenitor cells proliferation, EriB was effective on primary t(8;21) leukemia blasts and caused AML1-ETO degradation. In murine t(8;21) leukemia models, EriB remarkably prolonged the survival time or decreased the xenograft tumor size. Together, EriB might be a potential treatment for t(8;21) leukemia by targeting AML1-ETO oncoprotein and activating apoptosis pathways.

Animals↗
PubMed2006

Molecular response in acute promyelocytic leukemia: a direct comparison of regular and real-time RT-PCR.

Evaluation of molecular response is important for the diagnosis and monitoring of minimal residual disease in patients with acute promyelocytic leukemia (APL). In this study, we analyzed the molecular response by regular reverse transcription-polymerase chain reaction (RT-PCR) and quantitative real-time RT-PCR in 31 newly diagnosed patients. The real-time RT-PCR results are reported as normalized DoseN and log-reduction (3.0-4.9 log-reduction as minor and > or =5.0 log-reduction as major molecular response). After induction therapy and completion of consolidation, minor molecular response was documented in 35.5 and 96.8% patients, respectively, which was equivalent to the regular RT-PCR (22.6 and 96.8%), whereas the major molecular response rate was significantly lower (12.9 and 90.3%, respectively). All patients achieved major molecular response during and after maintenance therapy. During the follow-up study, loss of major molecular response was observed in two patients, which was associated with subsequent loss of minor molecular response, positive RT-PCR and then documentation of central nervous system leukemia or clinical relapse in 3-6 months. For summary, we demonstrated that the real-time RT-PCR is potentially superior to regular RT-PCR in evaluation of molecular response in APL patients and that reporting real-time RT-PCR data by log-reduction is feasible and clinically relevant.

Follow-Up Studies↗
PubMed2006

Imaging diagnosis of testicular lymphoma.

Testicular lymphoma is a rare clinicopathologic entity that has rapid progression and poor prognosis. This report describes a case of a 62-year-old man who presented with a large testicular tumor and extensive lymphadenopathy along the spermatic cord and gonadal vessels to the renal vein level. Testicular lymphoma was considered, and biopsy confirmed a non-Hodgkin, large, B-cell lymphoma. The distribution of lymphadenopathy differs from that of paraaortic lymph nodes that present as other testicular tumors (seminoma or nonseminoma). The finding may be a useful characteristic for timely diagnosis of testicular lymphoma, although the diagnosis should be suspected in an older patient who presents with a testicular neoplasm and increased lactic dehydrogenase levels but without increased alpha-fetoprotein and human chorionic gonadotropin levels.

Biopsy↗
PubMed2005

Immunodetection of pentamer and modified C-reactive protein using surface plasmon resonance biosensing.

In clinical practices, the examination of pentamer C-reactive protein (pCRP) is commonly used as a prognostic indicator of the risk of a patient developing cardiovascular disease (CVD). Structural modification of pCRP produces a modified CRP (mCRP) which exhibits different biological activities in the body. In recent years, mCRP has come to be regarded as a more powerful inducer than pCRP, and hence mCRP measurement has emerged as an important indicator for assessing the risk of developing CVD. The surface plasmon resonance (SPR) biosensing technique can be employed to increase the detection accuracy and real-time response when sensing pCRP or mCRP. In this study, three monoclonal antibodies (Mabs), C8, 8D8, and 9C9, are immobilized on a protein G layer for subsequent CRP detection. The experimental results reveal that the Mab C8 reacts with both pCRP and mCRP, the Mab 8D8 with pCRP, and the Mab 9C9 with mCRP. No false signals caused by non-specific binding are observed. When detecting pCRP using Mab C8, the SPR bioassay provides sufficient sensitivity to evaluate whether or not a patient is at risk of developing CVD. SPR biosensing provides a viable and accurate approach for the real-time evaluation of pCRP and mCRP levels, and is therefore of considerable benefit in clinical examinations of CPR.

Antibodies, Monoclonal↗
PubMed2005

Incidence of nasal trauma associated with nasal prong versus nasal mask during continuous positive airway pressure treatment in very low birthweight infants: a randomised control study.

OBJECTIVE: To compare the incidence of nasal trauma associated with the use of prong or mask during nasal continuous positive airway pressure (nCPAP) support in very low birthweight (<1501 g) infants. DESIGN: Randomised controlled clinical trial. SETTING: Tertiary care university hospital, Department of Paediatrics, Kuala Lumpur, Malaysia. METHODS: All very low birthweight infants admitted to the neonatal intensive care unit between July 2001 and December 2003 who received nCPAP through the Infant Flow Driver were randomised to the use of either nasal prong or mask. The nasal cavity of these infants was inspected daily during the first week and then weekly until they were weaned off nCPAP. RESULTS: Of the 89 infants recruited, 41 were randomised to the mask group and 48 to the prong group. There was no significant difference in the incidence of nasal trauma between the two groups (p = 0.5). The primary site of trauma was at the junction between the nasal septum and the philtrum in infants in the mask group and the walls of the nasal septum in the prong group. Logistic regression analysis showed that duration of nCPAP was the only significant risk factor associated with development of nasal injury, after birth weight, gestational age, and nasal device used had been controlled for (adjusted odds ratio 1.04; 95% confidence interval 1.01 to 1.07; p = 0.003). CONCLUSION: Irrespective of the type of nasal device used, nasal trauma is common during nCPAP treatment, which should therefore be terminated as soon as possible.

Continuous Positive Airway Pressure↗
PubMed2005

Clinical and cytogenetic features of 508 Chinese patients with myelodysplastic syndrome and comparison with those in Western countries.

Myelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell disorder characterized by ineffective hematopoiesis and leukemia progression. Racial differences may exist on clinical pictures and the molecular events leading to MDS, which are heterogeneous. To better define the clinical and cytogenetic features in Chinese patients, a retrospective multicentric study was performed in 508 MDS cases. Compared with Western countries, Chinese patients showed younger age (median: 49 vs 65-73 years), lower percentages of RARS (2.8 vs 6.6-15.3%), and CMML (5.2 vs 11.7-30.6%). Cytogenetically, among 367 cases with evaluable data, abnormal karyotypes were found in 136 cases, including 56 numerical and 80 structural changes. Incidences of single chromosome 5 and 7 abnormalities were lower than those in Western countries (2.2 vs 17.8-42.5%). However, complex cytogenetic aberrations and chromosome translocations were frequently observed and related to poor prognosis. Both multiple chromosome deletions and translocations were detected in advanced subtypes (RAEB and RAEB-T). Analysis of 200 cases revealed a higher incidence of hepatitis-B-virus infection than that in non-MDS population (21.00 vs 9.75%). This study further confirmed: (1) different genetic/environmental backgrounds between Asian and Western MDS populations; (2) a strong predictive value of cytogenetic abnormalities on disease outcome and involvement of genomic instability in leukemia clone development.

Adolescent↗
PubMed2004

A sensitivity comparison of optical biosensors based on four different surface plasmon resonance modes.

Current surface plasmon resonance (SPR) modes based on the attenuated total reflection (ATR) method can broadly be categorized as: conventional SPR, long-range SPR (LRSPR), coupled plasmon-waveguide resonance (CPWR), and waveguide-coupled SPR (WCSPR). Although the features of optical biosensors are dependent upon their particular SPR mode, a common requirement for all biosensors utilized for biomolecular interaction analysis (BIA) is a high degree of sensitivity. The current paper presents a theoretical analysis and comparison of the sensitivity and resolution of these four types of SPR biosensors when employed in three of the most prevalent detection methods, namely angular interrogation, wavelength interrogation, and intensity measurement. This study develops a detailed understanding of the influences of various biosensor design parameters in order to enhance the sensitivity and detection limit capabilities of such devices.

Computer Simulation↗
PubMed2004

A novel ultrahigh-resolution surface plasmon resonance biosensor with an Au nanocluster-embedded dielectric film.

The detection performance of conventional surface plasmon resonance (SPR) biosensors is limited to a 1 pg/mm(2) surface coverage of biomolecules, and consequently, such sensors struggle to detect the interaction of small molecules in low concentrations. The present study is attempted to propose the use of a novel SPR biosensor with Au nanoclusters embedded in a dielectric film to achieve a 10-fold improvement in the resolution performance. A co-sputtering method utilizing a multi-target sputtering system is used to fabricate the present dielectric films (SiO(2)) with embedded Au nanoclusters. It is shown that the sensitivity of the developed SPR biosensor can be improved by adjusting the size and volume fraction of the embedded Au nanoclusters in order to control the surface plasmon effect. The present gas detection and DNA hybridization experimental results confirm that the proposed Au nanocluster-enhanced SPR biosensor provides the potential to achieve an ultrahigh-resolution detection performance of approximately 0.1 pg/mm(2) surface coverage of biomolecules.

Argon↗
PubMed2004

Pulsatile ocular blood flow of choroidal neovascularization in asymmetric age-related macular degeneration after transpupillary thermotherapy.

PURPOSE: A previous study has shown that the pulsatile ocular blood flow (POBF) in eyes with asymmetric age-related macular degeneration (AMD) differs. Whereas eyes with drusen have higher POBF than contralateral eyes with disciform scarring, the POBF of eyes with drusen is lower relative to contralateral eyes with choroidal neovascularization (CNV). This study was designed to assess whether the POBF of eyes with CNV changes after transpupillary thermotherapy (TTT), using the contralateral eyes with drusen or scarring without TTT as controls. METHODS: In total, 26 patients with CNV in one eye and drusen or scarring in the other were enrolled in this prospective case series. Eyes with CNV were treated with TTT. POBF was measured monthly in both eyes of each subject. RESULTS: Before TTT, the POBF of eyes with CNV was 1179+/-317 microl/min. After TTT, the POBF of CNV eyes had decreased at 1 month (1015+/-273 microl/min, P=0.002) and 2 months (945+/-398 microl/min, P=0.011) of follow-up, but had rebounded at 3 months (P=0.441) and 6 months (P=0.084). CONCLUSIONS: These findings suggest that TTT decreases the pulsatile choroidal blood flow in eyes with CNV in patients with asymmetric AMD and the effects persist for 2 months. POBF may be used as a modality to monitor the therapeutic effects of CNV in asymmetric exudative AMD.

Aged↗
PubMed2004

Rapid induction of cAMP/PKA pathway during retinoic acid-induced acute promyelocytic leukemia cell differentiation.

The second messenger cyclic adenosine monophosphate (cAMP) plays an important role in cell proliferation, differentiation and apoptosis. In the present work, we evaluated the cAMP signaling in acute promyelocytic leukemia (APL) cells in the context of differentiation induced by all-trans retinoic acid (ATRA). There was a marked increase in the intracellular cAMP level within a few minutes after treatment with ATRA in APL cell line NB4 and fresh APL cells, whereas no such phenomenon was observed in NB4-R1 cells that are resistant to ATRA-induced maturation. In addition, the basal level of intracellular cAMP was lower in NB4-R1 than in NB4 cells. Mechanistic study showed that this induction of cAMP was mediated through the activation of adenylate cyclase. Moreover, we found that cAMP-dependent protein kinase (PKA) activity was quickly upregulated in parallel in ATRA-treated NB4 cells, and the phosphorylation of RARalpha by PKA could increase its transactivation effect. Use of H-89, an inhibitor of PKA, could partially suppress the transcriptional expression of ATRA target genes and ATRA-induced differentiation of APL cells. Taken together, we suggested a crosstalk between ATRA-induced cytosolic pathway and nuclear pathway in APL cell differentiation.

Adenylyl Cyclases↗
PubMed2004

Computed tomographic virtual cardioscopy in a case of left atrial myxoma.

Computed tomographic virtual cardioscopy was used to provide clear and precise visualisation of a myxoma with a stalk arising from the interatrial septum. This technique permits the safe, reliable, and non-invasive diagnosis of intracardiac lesions. This case is presented to assist the cardiovascular surgeon in preoperative planning or in developing a simulation of robotic cardiac surgery.

Female↗