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Biomedical subjects

S J Wang

Publications and source records attributed to S J Wang.

At least 37 records · Page 2Linked to original sources
PubMed2001

Analysis of large-volume DNA markers and polymerase chain reaction products by capillary electrophoresis in the presence of electroosmotic flow.

We have demonstrated on-line concentration and separation of DNA in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solutions. After injecting large-volumes DNA samples, PEO solutions entered a capillary filled with 400 mM Tris-borate (TB) buffers by EOF and acted as sieving matrices. DNA fragments stacked between the sample zone and PEO solutions. Because sample matrixes affected PEO adsorption on the capillary wall, leading to changes in EOF, migration time, concentration, and resolving power varied with the injection length. When injecting phiX174 RF DNA-HaeIII digest prepared in 5 mM Tris-HCl buffer, pH 7.0, at 250 V/cm, peak height increased linearly as a function of injection volume up to 0.9 microl (injection time 150 s). The sensitivity improvement was 100-fold compare to that injected at 25 V/cm for 10 s (0.006 microl). When injecting 1.54 microl of GeneScan 1000 ROX, the sensitivity improvement was 265-fold. The sensitivity improvement was 40-fold when injecting 0.17 microl DNA sample containing pBR 322/HaeIII, pBR 328/BglI, and pBR 328/HinfI digests prepared in phosphate-buffered saline. This method allows the analysis of polymerase chain reaction (PCR) products amplified after 17 cycles when injecting 0.32 microl (at 30 cm height for 300 s). The total analysis time was shorter (91.6 min) than that (119.6 min) obtained from injecting PCR products after 32 cycles for 10 s.

Base Sequence↗
PubMed2001

Lamotrigine inhibition of glutamate release from isolated cerebrocortical nerve terminals (synaptosomes) by suppression of voltage-activated calcium channel activity.

Lamotrigine (LAG) is an antiepileptic drug which is believed to suppress seizures by inhibiting the release of excitatory neurotransmitters. The present study was aimed at investigating the effect of LAG on the 4-aminopyridine (4AP)-evoked glutamate release in cerebrocortical nerve terminals (synaptosomes). LAG inhibited the release of glutamate evoked by 4AP in a concentration-dependent manner. This inhibitory effect was associated with a reduction in the depolarization-evoked increase in the cytoplasmic free Ca2+ concentration ([Ca2+]C). In addition, LAG did not alter the resting synaptosomal membrane potential or 4AP-evoked depolarization. Furthermore, ionomycin-evoked glutamate release was not affected by LAG. Based on these results, we suggest that presynaptic calcium influx blockade and inhibition of glutamate release may underlie the mechanism of action of LAG. These action may also contribute to their neuroprotective properties in excitotoxic injury.

4-Aminopyridine↗
PubMed2001

Group sequential test strategies for superiority and non-inferiority hypotheses in active controlled clinical trials.

In a group sequential active controlled clinical trial, the study hypothesis may be a superiority hypothesis that an experimental treatment is more effective than the active control therapy or a non-inferiority hypothesis that the treatment is no worse than the active control within some non-inferiority range. When it is necessary to plan for testing the superiority and the non-inferiority hypotheses, we propose an adaptive group sequential closed test strategy by which the sample size is planned for testing superiority and is to be increased for showing non-inferiority given that it is deemed more plausible than superiority based on the observed sample path during the course of the trial. The proposed adaptive test strategy is valid in terms of having the type I error probability maintained at the targeted alpha level for both superiority and non-inferiority. It has power advantage or sample size saving over the traditional group sequential test designed for testing either superiority only or non-inferiority only.

Controlled Clinical Trials as Topic↗
PubMed2001

Nuclear stopping as a probe for in-medium nucleon-nucleon cross sections in intermediate energy heavy ion collisions.

Using an isospin-dependent quantum molecular dynamics, nuclear stopping in intermediate heavy ion collisions has been studied. The calculation has been done for colliding systems with different neutron-proton ratios in beam energy ranging from 15 MeV/ u to 150 MeV/ u. It is found that, in the energy region from above Fermi energy to 150 MeV/ u, nuclear stopping is very sensitive to the isospin dependence of in-medium nucleon-nucleon cross section, but insensitive to symmetry potential. From this investigation, we propose that nuclear stopping can be used as a new probe to extract the information on the isospin dependence of in-medium nucleon-nucleon cross section in intermediate energy heavy ion collisions.

Journal Article↗
PubMed2001

Heat shock pretreatment influences the expression of PKC isoforms during sepsis.

Protein Kinase C (PKC) plays a central role in signal transduction and participates in diverse biological and biochemical functions. PKC dysfunction leads to general immunosuppression that, in turn, increases host susceptibility to infection and sepsis. In our previous study, we demonstrated that the mortality of sepsis is significantly decreased in rats treated with heat shock. It was considered that the modulation of PKC content by previous heat shock might contribute to the resistance to a severe infection. In this study, we attempted to understand the change of various PKC isoforms in the lymphocytes during sepsis and to investigate the role of previous heat shock in influencing PKC expression. Cecal ligation and puncture (CLP) was used as the experimental sepsis model for its biphasic clinical manifestation. Heat shock protein and PKC isoforms were detected by immunochemical study. Ten PKC isoforms (alpha, beta, gamma, delta, epsilon, zeta, theta, iota, lambda, and mu) were detected from peripheral lymphocytes. Results showed that all the PKC isoforms have a declination tendency along with the progression of CLP-induced sepsis, and previous heat shock treatment could prevent the declination of PKC content, particularly the isoforms beta, gamma, and epsilon, during sepsis. We suggest that heat shock response may participate in maintenance of PKC expression and contribute to decrease the severity of systemic infection.

Animals↗
PubMed2001

Uptake of gallium-67 citrate in clean surgical incisions after colorectal surgery.

Non-specific accumulation of gallium-67 citrate (gallium) in uncomplicated surgical incisions is not uncommon. It is important to know the normal pattern of gallium uptake at surgical incision sites in order to properly interpret the gallium scan when investigating possible wound infection in patients who have undergone abdominal surgery. We studied 42 patients without wound infection after colorectal surgery and performed gallium scans within 40 days after surgery. Patients were divided into three groups according to the interval between the operation and the scan. In group A (26 patients) gallium scan was performed within 7 days after surgery, in group B (8 patients) between 8 and 14 days after surgery, and in group C (8 patients) between 15 and 40 days after surgery. Our data showed that in group A, 61.5% had gallium accumulation at the surgical incision site. In group B, 50% had accumulation of gallium at the surgical incision site, while in group C only one patient (12.5%) showed gallium uptake. It is concluded that the incidence of increased gallium uptake at clean surgical incision sites is high after colorectal surgery. Nuclear medicine physicians should bear in mind the high incidence of non-specific gallium uptake at such sites during the interpretation of possible wound infection in patients after colorectal surgery.

Adolescent↗
PubMed2001

Colonic transit disorders in systemic sclerosis.

Systemic sclerosis (SS) alters smooth muscle function throughout the gastrointestinal tract, the oesophagus being the segment most often involved. Involvement of the colon, though less common, may lead to life-threatening complications. We studied 23 unselected patients with SS and 20 age-matched healthy controls using radionuclide colon transit studies. The geometric centre (GC) at 4 and 24 hours was used to summarise overall transit in the colon. In patients with SS, colon transit was delayed (GC4: 0.39 +/- 0.36 vs 0.85 +/- 0.45; P=0.001) (GC24: 1.68 +/- 0.9 vs 2.58 +/- 1.08; P=0.006). These findings suggest that delayed colon transit is common in patients with SS.

Adolescent↗
PubMed2001

Bilateral neurotrophic keratopathy complicating Vidian neurectomy.

PURPOSE: To present a case of bilateral neurotrophic keratopathy with miosis after bilateral Vidian neurectomy for vasomotor rhinitis. METHODS: Observational case report. RESULTS: A 68 year-old man presented with irritation and blurred vision in both eyes 2 weeks after bilateral Vidian neurectomy. Slit-lamp examination revealed a large epithelial defect, typical of neurotrophic keratopathy, in the inferior two-thirds of cornea in both eyes. Corneal sensitivity test with a Cochet-Bonnet anesthesiometer and electrical study of the blink reflex indicated bilateral trigeminal dysfunction. Both pupils were miotic, and tests with hydroxyamphetamine 1% and epinephrine 0.1% showed postganglionic sympathetic nerve damage. The corneal epithelial defects healed after 2 months of treatment with systemic prednisolone, vitamin B(12) and tarsorrhaphy. CONCLUSION: Neurotrophic keratopathy associated with dry eye syndrome may be a serious complication of Vidian neurectomy.

Aged↗
PubMed2001

Using patient-reportable clinical history factors to predict myocardial infarction.

Using a derivation data set of 1253 patients, we built several logistic regression and neural network models to estimate the likelihood of myocardial infarction based upon patient-reportable clinical history factors only. The best performing logistic regression model and neural network model had C-indices of 0.8444 and 0.8503, respectively, when validated on an independent data set of 500 patients. We conclude that both logistic regression and neural network models can be built that successfully predict the probability of myocardial infarction based on patient-reportable history factors alone. These models could have important utility in applications outside of a hospital setting when objective diagnostic test information is not yet be available.

Databases, Factual↗
PubMed2001

Quality of life differs among headache diagnoses: analysis of SF-36 survey in 901 headache patients.

This paper presents the results of health-related quality of life (HRQoL) in 901 patients consecutively visiting a headache clinic of a national medical center in Taipei, Taiwan. HRQoL was evaluated with the Medical Outcome Study-Short Form (SF-36) and the Hospital Anxiety and Depression Scale (HADS). According to the classification criteria for chronic daily headache (CDH) proposed by Silberstein et al. (Neurology 47 (1996) 871) five hundred and ninety-three (66%) patients had CDH, of whom transformed migraine (TM) was diagnosed in 310, and chronic tension-type headache (CTTH) in 231. One hundred and ninety-three patients had episodic migraine. All SF-36 scale scores significantly correlated with the HADS scores and the intensity and frequency of pain. Compared with the normative data, a pervasive multi-dimensional decline of the SF-36 scores was noted among the headache patients except for the physical functioning scale. The decline was most remarkable in the role limitations of physical and emotional dimensions and in the bodily pain. An increasing impairment of the SF-36 scores was noted from migraine to CTTH to TM. After controlling for the HADS, age, gender, education, and chronic illness by multiple linear regression analyses, the patients with TM had the worst SF-36 profile; whereas, the patients with CTTH and migraine had compatible results. This study is the first to demonstrate that the SF-36 scores differ among headache diagnoses. Psychological distress, as well as the percentages of the types of patients, greatly influenced the SF-36 scores in hospital-based headache samples. Our findings also suggest that improvement in the pain profile as well as psychological well-being can predict a generalized improvement in the SF-36 scales in headache patients.

Chronic Disease↗
PubMed2001

Histologic study of effects of radiation synovectomy with Rhenium-188 microsphere.

Rhenium-188 microsphere is a relatively new radiation synovectomy agent developed for the treatment of rheumatoid arthritis. It has been shown that the levels of unwanted extra-articular radiation are negligible with this agent. A histologic study was conducted to assess the effect of radiation synovectomy on synovium and articular cartilage after intra-articular injection of various doses of Re-188 microspheres into the knee joints of rabbits. Intra-articular injection of Re-188 microspheres into rabbit knee joints resulted in mild reactive inflammation and thrombotic occlusion of vessels which subsided rapidly. Sclerosis of subsynovium could be seen 12 weeks after injection. No evidence of damage to articular cartilage was noted. There was no significant difference in the articular pattern after injection of 0.3 or 0.6 mCi Re-188 microspheres. This study suggests that a treatment dose of Re-188 microspheres causes transient inflammation of synovium without any detectable damage to the articular cartilage of knee joint.

Animals↗
PubMed2001

Behavioral disorders and caregivers' reaction in Taiwanese patients with Alzheimer's disease.

OBJECTIVES: To evaluate the applicability of the Chinese version of the Neuropsychiatric Inventory Scale (NPI), and to explore the neuropsychiatric manifestations of Taiwanese patients with Alzheimer's disease (AD) and caregiver distress. METHOD: The Mini-Mental State Examination (MMSE) was administered to 95 patients with AD, and their caregivers were interviewed with the NPI. To assess the test-retest reliability of the Chinese version of the NPI, 86 caregivers underwent a second NPI 3 weeks later. RESULTS: The Cronbach's alpha coefficient of the Chinese version of the NPI was .76. The test-retest reliabilities of frequency, severity, and caregiver burden scores were significantly correlated; overall correlations were .85 for frequency (p < .001), .82 for severity (p < .001), and .79 (p < .001) for distress. Factor analysis was carried out, and three groups, "mood and psychosis," "psychomotor regulation," and "social engagement," were found. Aberrant motor behavior was the most frequently recorded behavior; euphoria was the least. There was no significant correlation between the patient's MMSE and the caregiver distress score, except for aberrant motor activity (r = -.23, p = .03). The symptoms most frequently reported to be severely distressing to caregivers were aberrant motor activity, anxiety, agitation, and delusions. CONCLUSIONS: These results indicate that the NPI is a reliable tool to assess behavioral disturbance and caregiver distress in Taiwanese AD patients. These findings also confirm the high prevalence of psychopathology among AD patients and the marked distress produced by many of these behaviors.

Aged↗
PubMed2001

Biotransformation kinetics of Pseudomonas putida for cometabolism of phenol and 4-chlorophenol in the presence of sodium glutamate.

A kinetic model to describe the degradation of phenol and cometabolic transformation of 4-chlorophenol (4-cp) in the presence of sodium glutamate (SG) has been developed and validated experimentally. The integrated model accounts for cell growth, toxicity of 4-cp, cross-inhibitions among the three substrates, and the different roles of the specific growth substrate (phenol) and the conventional carbon source (SG) in the cometabolism of 4-cp. In this ternary substrate system, the overall phenol degradation and 4-cp transformation rates are greatly enhanced by the addition of SG since SG is able to attenuate the toxicity of 4-cp and therefore increase the cell growth rate. Model analysis indicates that the maximum specific degradation rate of phenol (0.819 mg (mg.h)(-1)) is lowered by SG by up to 46% whereas the specific transformation rate of 4-cp is not directly affected by the presence of SG. The competitive inhibition coefficient of 4-cp to phenol degradation (Ki,cp) and that of phenol to 4-cp transformation (Ki,ph) were determined to be 6.49 mg l(-1) and 0.193 mg l(-1), respectively, indicating that phenol imposes much larger competitive inhibition to 4-cp transformation than the converse. The model developed can simultaneously predict phenol degradation and 4-cp transformation, and is useful for dealing with cometabolism involving multiple substrates.

Algorithms↗
PubMed2001

Frequency and predictors of physician consultations for headache.

We conducted a population-based headache questionnaire survey including questions on physician consultation for headache in Taipei, Taiwan from August 1997 to June 1998. The participants comprised 3377 subjects aged > or = 15 years, of whom 328 (9.7%) had a diagnosis of migraine and 1754 (52%) had a diagnosis of non-migraine headache. Migraineurs had a higher physician consultation rate (once or more in the past year) than the subjects with non-migraine headache (54% vs. 31%, P < 0.0001). When frequency > or = 10 times was taken as 10 times, the analysis showed that migraineurs consulted physicians more often than non-migraine headache subjects (2.36 vs. 0.96, P = 0.04). A small proportion of the subjects with either migraine (12%) or non-migraine headache (6%) accounted for 50% of total consultations within their groups. In addition to old age, low education levels, living in a rural area, migrainous features (nausea and photophobia), and work day loss, predictors of physician consultations also included 'having been troubled with headache' (odds ratio (OR) = 1.7) and co-morbidity with hypertension (OR = 1.8) or heart disease (OR = 2.2). Low copayment and unrestricted access to medical care, as well as cultural factors played an important role in the high consultation rates in our headache subjects. Moreover, this study found self-perception of headache impact and co-morbid illnesses were important factors affecting the decision to consult physicians about headache.

Data Collection↗
PubMed2001

Chronic daily headache in Taipei, Taiwan: prevalence, follow-up and outcome predictors.

We conducted a two-stage population-based headache survey among subjects aged > or = 15 in Taipei, Taiwan. Subjects with chronic daily headache (CDH) in the past year were identified, interviewed and followed-up. CDH was defined as a headache frequency > 15 days/month, with a duration > 4 h/day. Of the 3377 participants, 108 (3.2%) fulfilled the criteria for CDH, with a higher prevalence in women (4.3%) than men (1.9%). TM was the most common subtype (55%), followed by CTTH (44%). Thirty-four per cent of the CDH subjects overused analgesics. At the 2-year follow-up, 35% of the CDH subjects still had CDH. The significant predictors for persistent CDH at follow-up included: older age ( > or = 40 years) (RR = 2.4), CDH onset after 32 years (RR = 1.8), CDH duration > or = 6 years (RR = 2.0), medication overuse (RR = 1.8), and "daily" headache (RR = 2.1). We found that CDH is not uncommon in the community and its prevalence is similar among different populations. Older subjects and those with medication overuse may have a more protracted course of illness.

Adolescent↗
PubMed2001

Persistent migrainous visual phenomena might be responsive to lamotrigine.

Two patients with migraine reported having experienced persistent auralike visual phenomena for months to years. All laboratory investigations were normal except for occipital hypoperfusion on the brain single photon emission computed tomography. After lamotrigine treatment for 2 weeks, they both had a resolution of the visual symptoms. Persistent migrainous visual phenomena are potentially benign and probably a status of spontaneous aura.

Adult↗
PubMed2001

Dissociation of modular total hip arthroplasty at the femoral head-neck interface after loosening of the acetabular shell following hip dislocation.

Modular component dissociation is a potential problem of current modular total hip arthroplasty (THA) systems. We describe a case of dissociation of the modular THA at the femoral head-neck interface after loosening of the acetabular shell during closed reduction for posterior dislocation of THA. The causes of this dissociation and acetabular shell loosening are discussed. Successful treatment was provided with surgical revision of the acetabular and the femoral head components. The present case serves as a graphic reminder that the acetabular shell overhanging the acetabular bone must be avoided when implanting modular THA components.

Biomechanical Phenomena↗