Biomedical subjects

W H Chen

Publications and source records attributed to W H Chen.

At least 73 records · Page 4Linked to original sources

PubMed1998

A comparison of micromanometric and standard manometric techniques for recording of oesophageal motility.

Perfused micromanometric assemblies with an outer diameter of 2 mm or less have been developed for use in premature infants and small laboratory animals. Such assemblies offer advantages with regard to subject comfort and low perfusion rates that make them attractive for use in adults. The aim of this study was to investigate the recording fidelity of micromanometric assemblies in the measurement of oesophageal peristalsis in adults. Two micromanometric assemblies with an outer diameter of 1.8-2.0 mm and a length suitable for use in adults (165 cm), and containing micromanometric lumina of 0.28-0.35 mm i.d. and a standard lumen of 0.6-0.75 mm i.d. were evaluated. Each assembly was tested by measurement of pressure rise rate in response to sudden occlusion, and in vivo during oesophageal peristalsis by simultaneous comparison with an intraluminal strain gauge. At perfusion rates of 0.01-0.15 mL min-1 microlumina achieved pressure rise rates of 21-430 mmHg sec-1 that were comparable to 37-390 mmHg sec-1 for the standard lumina perfused at 0.15-0.6 mL min-1. During oesophageal peristalsis, micromanometric lumina recorded the occurrence and timing of all pressure waves accurately when compared with standard lumina and the microtransducer. However, microlumina under-recorded pressure wave amplitude to varying degrees dependent upon perfusion rate although the performance of microlumina could be improved to that of the standard lumen by shortening their length to 70 cm. Micromanometric assemblies are suitable for recording oesophageal peristalsis in adults although there is some impairment of absolute manometric fidelity. Fidelity can be improved by minimizing total assembly length.

Adult↗

PubMed1998

Characterization of terminal NeuNAcalpha2-3Galbeta1-4GlcNAc sequence in lipooligosaccharides of Neisseria meningitidis.

Group B and C Neisseria meningitidis are the major cause of meningococcal disease in the United States and in Europe. N . meningitidis lipooligosaccharide (LOS), a major surface antigen, can be divided into 12 immunotypes of which L1 through L8 were found among Group B and C organisms. Groups B and C but not Group A may sialylate their LOSs with N-acetylneuraminic acid (NeuNAc) at the nonreducing end because they synthesize CMP-NeuNAc. Using sialic acid-galactose binding lectins as probes in an ELISA format, six of the eight LOS immunotypes (L2, L3, L4, L5, L7, and L8) in Groups B and C bound specifically to Maackia amurensis leukoagglutinin (MAL), which recognizes NeuNAcalpha2-3Galbeta1-4GlcNAc/Glc sequence, but not to Sambucus nigra agglutinin, which binds NeuNAcalpha2-6Gal sequence. The combination of SDS-PAGE and MAL-blot analyses revealed that these six LOSs contained only the NeuNAcalpha2-3Galbeta1-4GlcNAc trisaccharide sequence in their 4.1 kDa LOS components, which have a common terminal lacto-N-neotetraose (LNnT, Galbeta1-4GlcNAcbeta1-3Galbeta1-4Glc) structure when nonsialylated as shown by previous studies. The LOS-lectin binding was abolished when the LOSs were treated with Newcastle disease viral neuraminidase which cleaves alpha2-->3 linked sialic acid. Methylation analysis of a representative LOS (L2) confirmed that NeuNAc is 2-->3 linked to Gal. Thus, these LOSs structurally mimic certain glycolipids, i.e., paragloboside (LNnT-ceramide) and sialylparagloboside and some glycoproteins in having LNnT and N-acetyllactosamine sequences, respectively, with or without alpha2-->3 linked NeuNAc. The molecular mimicry of the LOSs may play a role in the pathogenesis of N.meningitidis by assisting the organism to evade host immune defenses in man.

Antigens, Bacterial↗

PubMed1998

Prevalence of extracranial carotid and vertebral artery disease in Chinese patients with coronary artery disease.

BACKGROUND AND PURPOSE: Chinese have been reported to have an extremely low prevalence rate of carotid and vertebral artery disease in comparison with whites. Previous studies, however, have been limited to general hospital stroke admission or postmortem series and were prone to selection bias. Extracranial cerebrovascular disease (ECCVD) is associated with coronary artery disease (CAD) in whites. Data associating ECCVD with CAD in Chinese patients are not available. METHODS: We studied 153 consecutive Chinese patients with angiographically documented CAD. Duplex ultrasonography was performed to identify any underlying extracranial carotid and vertebral artery disease. Patient demographics; vascular risk factors; history of myocardial infarction, transient ischemic attack (TIA) or stroke; concomitant peripheral vascular disease (PVD); degree of left ventricular dysfunction; and extent and severity of CAD were also noted and analyzed. RESULTS: Significant (> or = 50%) stenosis of one or more of the extracranial cerebral arteries was found in 32 patients (21%). The internal and external carotid arteries were involved in 17 of 153 patients (11%) and 19 of 153 patients (12%), respectively. The vertebral artery was involved in 9 of 153 patients (6%) and the common carotid artery in 3 of 153 (2%). Diabetes mellitus, hypertension, a history of TIA or stroke, and PVD were significantly associated with the presence of ECCVD. CONCLUSIONS: Significant ECCVD is not uncommon in Chinese patients with CAD, and the prevalence is comparable with that reported in white populations. Patients with a history of diabetes, hypertension, TIA, stroke, and PVD are more likely to have concomitant ECCVD.

Aged↗

PubMed1998

Cavernous sinus syndrome and hepatoma metastasis.

A 46-year-old man presented with left cavernous sinus syndrome and subsequent right leg pain proved clear cell type hepatocellular carcinoma metastasis. An initial liver function test was normal and alpha-fetoprotein was only 15 ng/ml but they increased rapidly and he progressed to hepatic failure 2 weeks later. Therefore, a subclinical hepatoma with metastasis should be differentiated in cavernous sinus syndrome, even in cases of normal hepatic enzymes, because hepatoma is prevalent in Taiwan.

Carcinoma, Hepatocellular↗

PubMed1998

Congenital renal arteriovenous malformations: two cases report.

Congenital arteriovenous malformation (AVM) of the kidney is a rare condition. Rupture of an AVM in the kidney may cause hematuria, flank pain, and urinary retention due to clots. We report 2 cases of congenital renal AVM. Both were treated with transcatheter renal arterial embolization. The signs and symptoms disappeared after embolization. On follow-up, renal function testing with a DMSA scan revealed only focal loss of renal cortical function. The clinical courses of 2 cases are reported and the literature is reviewed.

Adult↗

PubMed1998

Transcervical embryoscopic diagnosis of conjoined twins in a ten-week missed abortion.

Embryoscopic diagnosis of conjoined twins presenting with a missed abortion has never been reported. The morphological and pathological examinations, and the exact time of death in the conceptus of a missed abortion are seldom clearly delineated. The newly developed field of embryoscopy has created a new frontier in early embryonic/fetal visualization and is able to confirm the sonographic diagnosis. In this report, we used a transcervical endoscope to verify conjoined twins (thoraco-omphalopagus) in a 10-week missed abortion. Based on the size and the external features of the dead embryo, which exhibited developmental arrest at nine weeks and three days of menstrual age, we estimated that the embryo had died four days before examination. The whole procedure proceeded smoothly without any immediate complications.

Abortion, Missed↗

PubMed1998

Endobronchial metastasis from an occult papillary thyroid carcinoma: a case report.

It is well known that occult papillary thyroid cancers can result in regional lymph node metastasis. However, this small, clinically undetectable cancer rarely causes distant metastasis; moreover, an endobronchial presentation has not been described previously. We report on a 48-year-old man who experienced hemoptysis. A fiberoptic bronchoscopic biopsy established the diagnosis of endobronchial metastasis in the absence of clinically apparent thyroid cancer. After the patient was treated with a total thyroidectomy and radioactive iodine (131I), a whole body radioiodine scan revealed no evidence of distant functioning metastasis. A histological evaluation of the thyroid gland showed the presence of a 0.2 x 0.2 x 0.2 cm nodule in the right lobe. A left pneumonectomy was undertaken to treat the distant metastasis of the disease. Since most papillary thyroid carcinomas are curable, an aggressive surgical approach to the solitary metastasis is indicated.

Bronchial Neoplasms↗

PubMed1998

Vitreous treatment of retinal pigment epithelial cells results in decreased expression of FGF-2.

PURPOSE: Changes in gene expression were investigated after treatment of cultured human retinal pigment epithelial (RPE) cells with vitreous. This may have implications for proliferative diseases such as proliferative vitreoretinopathy. METHODS: Cells were cultured in the presence or absence of human vitreous, and gene expression was examined using the differential display polymerase chain reaction technique. Differentially expressed RNAs were cloned, screened for differential expression, and sequenced. The expression of one of these RNAs (that for fibroblast growth factor [FGF]-2/basic FGF) was examined by in situ hybridization and ribonuclease protection assays. The level of FGF-2 protein was examined by immunoblot analysis. The effects of adding FGF-2 to cells cultured in the presence of vitreous were examined. RESULTS: Treatment of low passage human RPE cells with 25% vitreous resulted in the epithelial-to-fibroblast-like morphologic changes reported by others and in the decreased expression of FGF-2 mRNA and FGF-2 protein. Addition of FGF-2 to cultures at the same time as addition of vitreous prevented some of the effects of vitreous on these cells. CONCLUSIONS: Vitreous treatment of RPE cells in culture results in decreased expression of FGF-2 mRNA and protein. Because supplementation of FGF-2 prevents some of the vitreous-mediated effects, this may indicate that modulation of FGF-2 levels by the vitreous may play an important role in the phenotypic changes seen in RPE cells exposed to vitreous.

Cells, Cultured↗

PubMed1997

Bilateral cheiro-oral syndrome.

Eight cases of pure bilateral cheiro-oral syndrome (COS) are reported. The location and etiology of lesion were well defined in six cases, including pontine infarct in three, and brainstem hemorrhage, unilateral thalamic infarct and bilateral subdural hematoma in one patient each respectively. Neuroimaging and neurophysiological studies were normal in another two patients. Taken together with the previous five reported cases of bilateral COS, pons is the most frequent site for presentation even in the absence of associated brainstem signs.

Adult↗

PubMed1997

Double filtration plasmapheresis in the treatment of inflammatory polyneuropathy.

Twelve cases of recognized inflammatory polyneuropathy were treated by plasmapheresis (PP) at Shin-Kong Wu Ho-Su Memorial Hospital from November 1993 to November 1995. These include 6 cases of acute inflammatory demyelinating polyneuropathy (AIDP), 4 cases of chronic inflammatory demyelinating polyneuropathy (CIDP), one case of Fisher syndrome, and one case of Sjögren's syndrome with polyneuropathy. The patients chosen for PP met the inclusion criteria of severely disabled, i.e., Grade 4 (bed or chair bound) or Grade 5 (required assisted ventilation), or an unremittingly progressive course. Plasmapheresis was carried out by the double filtration method. Each patient received a standard course of at least 4 sessions of pheresis. All the patients receiving PP showed a beneficial response. The treatment for 10 patients was judged to be effective. The other 2 patients (one AIDP and one CIDP), though improved, were unable to reach Grade 2. Among the complications of PP, only 4 episodes of symptomatic hypotension were noted in a total of 73 sessions of PP. In conclusion, PP is safe and effective in treating inflammatory polyneuropathy.

Adult↗

PubMed1997

Service quality of Chinese traditional medicine in Taiwan: a comparative study.

A consensus is growing that measuring service quality level based on patients' perceptions is crucial for continuous improvement. This work involved a questionnaire survey to evaluate the gap of perceived service quality level between Chinese traditional medicine and Western medicine in Taiwan. The ten dimensions of service quality proposed by Parasuraman et al. (1985) were adopted as a framework to design an instrument. The results of data analyses indicated that significant differences arise in perceived quality level between the two systems in four dimensions: competency, tangibles, courtesy, and communication. Managerial implications of the results were discussed. We recommend that the two systems learn from each other to enhance patient satisfaction.

Adult↗

PubMed1997

[An investigation on the family support of discharged acute myocardial infarction patients].

Acute myocardial infarction (AMI) is a kind of diseases. The rehabilitation of AMI patients is affected by many psychosocial factors, the family support is one of these factors. In this research, two groups of patients were interviewed by the author with the Family APGAR Questionnaire, one group was of the patients who discharged 4-6 years ago, the other group was of the patients who discharged 5-7 months ago. The result was that the family support of five-year group was better than that of half-year group. So, the education for patient's family numbers was very important and should be thought highly by nurses.

Family↗

PubMed1997

Characterization of Ca(2+)- and voltage-dependent nonselective cation channels in human HepG2 cells.

Nonselective cation channels have been identified and linked to important cell functions in rat hepatocytes. In this study, we characterized inward rectifying nonselective cation channels in detail by the patch clamp technique in human HepG2 cells. Channel properties were studied with high resistance borosilicate pipettes in cell-attached and inside-out configurations. With Ringer's solution and KCl as pipette solutions, the conductances were 19.7 +/- 2.1 and 22.2 +/- 0.0 picosiemens (pS), and reversal potentials were 30.9 +/- 3.5 and 31.3 +/- 4.6 mV, respectively. The channel was permeable to Ba2+, and the sequence of permeability ratios was Na+ > K+ > Cs+ > Ba2+. In the cell-attached configuration, the channel had a higher opening probability at depolarizing potential than at hyperpolarizing. In the inside-out patches with symmetric Ringer's solution, the current voltage curve was linear with conductance of 19.8 +/- 0.9 pS. Reversal potential shifted from -0.2 +/- 1.0 mV to 23.2 +/- 1.0 mV when the bath solution was replaced by dilute Ringer's solution. In the inside-out configuration, the gating was Ca(2+)-dependent, and the opening probability increased with increasing intracellular calcium concentration ([Ca2+]i). An outward rectifying channel appeared when [Ca2+]i was less than 1 mumol/L. The nonselective channel was reversibly blocked by 10 mumol/L internal flufenamic acid. We conclude that Ca(2+)- and voltage-dependent nonselective cation channels are present in human HepG2 cells. The channels might be involved in the regulation of Ca2+ influx and are associated with activation of other ion channels.

Animals↗

PubMed1997

Antiplatelet drugs induce apoptosis in cultured cancer cells.

In order to understand if antiplatelet drugs possess direct antineoplastic property, we tested the apoptotic effect of 5 popularly marketed antiplatelet drugs in Taiwan in 6 cultured cancer cell lines (Hep 3B hepatocarcinoma, U87-MG malignant glioma, PC-3 prostate adenocarcinoma, HeLa cervical adenocarcinoma, HL-60 preleukemia and K-562 chronic myelogenous leukemia). While acetylsalicylate and flunarizine exerted no effect on these cancer cells, pentoxifyline (PTX), dipyridamole (DYA) and ticlopidine hydrochloride (T. HCl) displayed a time and dose-dependent apoptotic effect on them except for HL-60 and K-562 cells. PTX induced apoptosis in U87-MG, Hep 3B and HeLa cells, DYA in HeLa cells, while T. HCl in U87-MG, Hep 3B, PC-3 and HeLa cells. Adriamycin also provoked apoptotic effect in all 6 cell lines but neither PTX, DYA nor T. HCl acted synergy with adriamycin to HeLa cells, implicating that they may share a similar pathway for inducing apoptosis. Therefore, our results show that the antiplatelet drugs do possess antineoplastic property in vitro. A co-administration of antiplatelet drugs is noteworthy for an alternative adjunctive therapy in cancer patients.

Antineoplastic Agents↗

PubMed1997

Extensive thrombophlebitis with reactive thrombocytosis in a high risk Chinese parturient associated with retained placenta increta: a case report.

Postpartum thrombophlebitis is an infrequent disorder in Chinese women. A case is reported of extensive postpartum thrombophlebitis involving 23 cm of the femoral and pelvic veins. This 25-year-old splenectomized victim of beta-thalassemia was bedridden for 12 weeks because of threatened premature labor before Cesarean delivery. During the operation, placenta increta with massive bleeding was encountered. To save the uterus, ten percent of the placenta was retained. Duplex color Doppler imaging was performed for the diagnosis and follow-up of the thrombosis and vigorous anticoagulation therapy successfully cured this patient.

Adult↗

PubMed1997

Prediction of total cholesterol: high-density-lipoprotein-cholesterol ratio in young adults.

Abnormal cholesterol fraction is an essential risk factor for atherosclerosis of large cerebral arteries in young Asians. In order to reduce the medical cost and social resource for cholesterol electrophoresis, especially in undeveloped and developing Asian countries, we evaluated the validity of Nanji's GUT score for predicting TC: HDLC ratio in this population. Results showed that GUT score only predicted 71% of them. We also tested the predictive power of CUT index, and predicting rate was 81%. Therefore, Nanji's GUT score is not an ideal surrogate for cholesterol electrophoresis. We recommend CUT index to screen for high-risk subjects till a new method can satisfy the economic pattern in Asian countries.

Adult↗

PubMed1997

Reflex rhinorrhea after a right caudate infarct.

After a right caudate infarct, a 57-year-old man developed a left reflex rhinorrhea induced by gustation. Since data from the blink reflex and facial electrodiagnosis were normal, a disinhibitory response from caudate nucleus to superior salivatory nucleus is proposed.

Caudate Nucleus↗

PubMed1996

Interference of cellular phones with implanted permanent pacemakers.

BACKGROUND AND HYPOTHESIS: Occasional reports have suggested that cellular phones may interfere with permanent pacemakers. Our investigation sought to determine systematically the effects of commercially available cellular phones on the performances of different pacing modes and sensing lead configurations of permanent implanted pacemakers. METHODS: We conducted the study in 29 patients implanted with single- or dual-chamber bipolar rate-adaptive permanent pacemakers (a total of nine different models and six different sensors: minute ventilation, activity sensing using either accelerometer or piezoelectric crystal, QT and oxygen saturation sensing) from four different manufacturers. Three different cellular phones with analog or digital coding with maximum power from 0.6 to 2 W were used to assess the effect of pacemaker interference. Each cellular phone was positioned at (1) above the pacemaker pocket, (2) the ear level ipsilateral to the pacemaker pocket, and (3) the contralateral ear level. Surface electrocardiograms, intracardiac electrograms, and marker channels were recorded where possible during the following maneuvers at each position: (1) calls made by a stationary phone to cellular phone, and (2) calls made from the cellular phone to a stationary phone. A total of eight different pacing modes [DDD(R), VDD(R), AAI(R) and VVI(R)] in both unipolar and bipolar sensing configurations was tested. RESULTS: Interference was demonstrated during cellular phone operation in 74 of 2,418 (3.1%) episodes in eight patients. Three types of interference were observed: inhibition of pacing output, rapid ventricular tracking in DDD(R) or VDD(R) mode, and asynchronous pacing. All were observed only with the cellular phone positioned above the pacemaker pocket. Interference occurred prior to and after the termination of the ringing tone of the cellular phone in 57% of cases. Cellular phones with either digital or analog technology could cause interference. Unipolar atrial lead was most susceptible to interference (relative frequency of interference: unipolar 1.8%, bipolar 0.4%, p < 0.05; atrial 2.9%, ventricular 1%, p < 0.05). There was no sensor-driven rate acceleration during all tests. In all patients, reprogramming of the sensitivity level successfully prevented cellular phone interference. CONCLUSIONS: Commercially available cellular phones can cause reversible interference to implanted single- or dual-chamber permanent pacemakers. The effect is maximal with high atrial unipolar sensitivity, especially in single pass VDD(R) systems. Both digital and analog cellular phones can lead to interference. Pacemaker interference can occur prior to a warning sign (ringing tone) of the phone and may have significant implications in patient safety.

Adult↗