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Biomedical subjects

M L Chen

Publications and source records attributed to M L Chen.

At least 73 records · Page 4Linked to original sources
PubMed2000

Application of pulsed-field gel electrophoresis to the investigation of a nosocomial outbreak of Vibrio parahaemolyticus.

The method of pulsed-field gel electrophoresis (PFGE) for Vibrio parahaemolyticus was first published in 1996. Since then, its application has been seldom reported in the literature. A food poisoning outbreak due to V. parahaemolyticus occurred in five wards of a hospital was investigated using this method. Twenty-five patients were involved and all of them had eaten food supplied by the hospital. Of the 15 cases whose stools were available for culture, only four cultures yielded V. parahaemolyticus. All four isolates were serotype K6 and were indistinguishable or closely related to each other based on PFGE patterns. Two isolates from food were recovered and they presented different characterizations from the patient isolates in both serotype and PFGE pattern. Successful typing by PFGE to identify the outbreak strain and differentiate V. parahaemolyticus strains between patient and food isolates in this study suggests the usefulness of PFGE for V. parahaemolyticus, the leading cause of food poisoning in Taiwan.

Cross Infection↗
PubMed2000

Anxiety and depression in Taiwanese cancer patients with and without pain.

The purpose of this investigation was to compare anxiety and depression in Taiwanese cancer patients with and without pain. In 1998, a convenience sample of 203 hospitalized cancer patients, 77 with pain and 126 without pain, were assessed for anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). Disease-related factors such as performance status, disease stage and perceived treatment effect were also assessed and controlled for their effect on anxiety and depression. The prevalence of both anxiety and depression in the pain group was significantly higher than that for the pain-free group. After controlling the effect of disease-related factors, patients' pain status had a significant effect on depression, but not on anxiety. Patients with pain had more depressive symptoms than patients without pain. Cancer patients' anxiety can be predicted significantly by functional status and perceived treatment effect. In addition to pain status, cancer patients' depression can be predicted by their functional status.

Analysis of Variance↗
PubMed2000

[A multiparametric monitoring network system based on windows operation system].

This paper introduces the general structure and implementary method both in hardware and software of a monitoring network system, which is developed for monitoring physiological multi-parameter under Windows operation system and based on personal computer. The parameters monitored by the system include Electrocardiogram (ECG), Noninvasive Blood Pressure (NIBP), Oxygen Saturation (SpO2), Respiration (RESP) and Body Temperature. Monitoring data can be shared by internal hospital network. The system has the advantages of easy operation and flexible structure. It is a new kind of hospital monitoring equipment.

Blood Pressure Determination↗
PubMed1999

Mechanistic studies to evaluate the enhanced antiproliferation of human keratinocytes by 1alpha,25-dihydroxyvitamin D(3)-3-bromoacetate, a covalent modifier of vitamin D receptor, compared to 1alpha,25-dihydroxyvitamin D(3).

1alpha,25-Dihydroxyvitamin D(3)-3-bromoacetate (1, 25(OH)(2)D(3)-3-BE), an affinity labeling analog of 1alpha, 25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), displayed stronger antiproliferative activities than 1,25(OH)(2)D(3) at 10(-10)-10(-6) M dose levels in cultured human keratinocytes (CHK). Additionally, preincubation of the cells with 10(-6) M 1,25(OH)(2)D(3), followed by treatment with various doses of 1,25(OH)(2)D(3)-3-BE, resulted in a significantly stronger antiproliferative activity by the mixture than individual reagents at every dose level. To search for a mechanism of this observation, we determined that [(14)C]1, 25(OH)(2)D(3)-3-BE covalently labeled human recombinant 1alpha, 25-dihydroxyvitamin D(3) receptor (reVDR) swiftly (<1 min) with a 1:1 stoichiometry and induced conformational changes (in VDR) that are different from 1,25(OH)(2)D(3), by limited tryptic digestion. Furthermore, a protein band, corresponding to reVDR, was specifically labeled by [(14)C]1,25(OH)(2)D(3)-3-BE in CHK extract, indicating that VDR is the main target of [(14)C]1, 25(OH)(2)D(3)-3-BE. The above-mentioned observations suggest that a rapid covalent labeling of VDR in CHK might alter the interaction between the holo-VDR and 1,25(OH)(2)D(3)-controlled genes. Furthermore, we observed that 1,25(OH)(2)D(3)-3-BE significantly decreased the binding of VDR to human osteocalcin vitamin D responsive element (hOCVDRE), as well as the dissociation rate of VDR from hOCVDRE, compared with 1,25(OH)(2)D(3) in COS-1 cells, transiently transfected with a VDR construct. Additionally, 1, 25(OH)(2)D(3)-3-BE was found to be more potent in inducing 1alpha, 25-dihydroxyvitamin D(3)-24-hydroxylase (24-OHase) promoter activity and mRNA expression in keratinocytes. The accumulation of 24-OHase message was also prolonged by the analog. Collectively these results indicated that rapid covalent labeling of VDR in keratinocytes (by 1, 25(OH)(2)D(3)-3-BE) might result in the conversion of apo-VDR to a holo-form, with a conformation that is different from that of the 1, 25(OH)(2)D(3)-VDR complex. This resulted in an enhanced stability of the 1,25(OH)(2)D(3)-3-BE/VDR-VDRE complex and contributed to the amplified antiproliferative effect of 1,25(OH)(2)D(3)-3-BE in keratinocytes.

3T3 Cells↗
PubMed1999

The PM2.5 and PM10 particles in urban areas of Taiwan.

This study conducted an atmospheric aerosol sampling to measure the PM10 (particles < 10 microns in aerodynamic diameter) and PM2.5 (particles < 2.5 microns in aerodynamic diameter) mass concentrations from October 1996 to June 1997 in northern (Taipei), central (Taichung) and southern (Kaohsiung), the three largest cities of Taiwan. Seventy-eight samples were obtained to measure the mass concentrations of PM10 and PM2.5 from nine sampling sites. According to those results, the PM10 mass concentrations in Taipei, Taichung and Kaohsiung were 42.19, 60.99 and 77.10 micrograms/m3, respectively. The corresponding PM2.5 mass concentrations were 23.09, 39.97 and 48.47 micrograms/m3, respectively. The PM2.5 fraction accounted for 61-67% of the PM10 mass in central and southern Taiwan, but was lower (54-59%) in northern Taiwan. Some samples in which the PM2.5 fraction was overwhelmingly dominant could reach as high as 80-95% of the PM10 mass. In addition, the PM2.5, PM10 levels and PM2.5/PM10-2.5 (particles with aerodynamic diameters ranging from 2.5 to 10 microns) ratios in metropolitan Taiwan significantly fluctuated from site-to-site and over time. Moreover, ambient daily PM2.5 and PM10-2.5 mass concentrations did not correlate well with each other at most of the sampling sites, indicated that they originated from different kinds of sources and emitted variedly over time.

Air Pollutants↗
PubMed1999

Adsorptive and electrochemical behaviors of estradiol valerate at a mercury electrode.

It was found that estradiol valerate could be adsorbed at a mercury electrode under open circuit. The adsorptive and electrochemical behaviors of estradiol valerate on a static mercury electrode were investigated by cyclic voltammetry, linear scan voltammetry and chronocoulometry. Based on this, a sensitive and selective adsorptive stripping square-wave voltammetric method was developed for the determination of estradiol valerate based on the optimization of solution conditions and electrochemical parameters. It was found that in a Britton-Robinson buffer solution containing 18% alcohol (pH 9.5), estradiol valerate gave a sensitive reductive peak at potential -1.29 V (vs. SCE) and the peak current was linear with the concentration of estradiol valerate in the range 2.0 x 10(-8)-2.5 x 10(-6) mol L-1. The detection limit was 1.1 x 10(-8) mol L-1. The interference of some common steroid estrogens was examined and it was found that they did not interfere in the determination of estradiol valerate in the present system.

Adsorption↗
PubMed1999

Validation of the structure of the perceived meanings of cancer pain inventory.

This study examined the structure of a newly developed instrument measuring the meaning of cancer pain for Taiwanese patients. The Perceived Meanings of Cancer Pain Inventory (PMCPI) was developed based on Lazarus's cognitive theory of emotion and on findings from qualitative interviews. The 27-item PMCPI contains six scales: loss, threat, challenge, blame-others, blame-self, and spiritual awareness. Two hundred cancer patients from three hospitals in northern Taiwan who were experiencing pain were included in the study. A series of confirmatory factor analyses were conducted to test the fit of specified measurement models. The results indicated that only the loss, threat, challenge and spiritual awareness scales possessed good construct validity, while blame-other and blame-self failed to show a satisfactory fit with the data. Correlation coefficients among the scales were also estimated. Parallel-item testing demonstrated that the items of each valid scale had the same factor loading and error variance.

Adult↗
PubMed1999

Development and testing of the Family Caregiving Consequences Inventory for home nursing assessment in Taiwan.

This paper describes the development and psychometric testing of the Family Caregiving Consequences Inventory (FCCI). Data were collected from a convenience sample of 97 families in Taiwan to examine the validity and reliability of the three FCCI scales: frail elder outcomes, caregiver outcomes and family outcomes. Acceptable test-retest and internal consistency reliabilities were found, though inter-rater reliability was unsatisfactory. Criterion-related validity was demonstrated by congruence with home nursing specialists' assessment of family caregiving outcomes. Confirmatory factor analysis with a good overall model fit supported the construct validity of FCCI. However, a poor fit of the internal measurement structure was found for the frail elder outcomes scale and the family outcome scale. Studies with larger samples are needed to further verify the measurement models used here. Nevertheless, in its current form, the FCCI can be used to increase the sensitivity of home care nurses to family caregiving situations and provide an instrument for studies of family caregiving in Taiwan and other countries with similar home care needs.

Aged↗
PubMed1999

The effectiveness of acupressure in improving the quality of sleep of institutionalized residents.

BACKGROUND: Elderly people often suffer from disturbed sleep. Because traditional Chinese medicine indicates that acupressure therapy may induce sedation, testing the effectiveness of acupressure in enhancing the quality of sleep of institutionalized residents with a well-designed scientific study is needed. METHODS: A randomized block experimental design was used. The Pittsburgh Sleep Quality Index (PSQI) questionnaire was used as a screening tool to select subjects with sleep disturbance. By matching the effects of hypertension, hypnosis, naps, and exercise, subjects were randomly assigned to an acupressure group, a sham acupressure group, and a control group. Each group had 28 subjects for a total of 84 subjects. The same massage routine was used in the acupressure group and the sham acupressure group, whereas only conversation was employed in the control group. RESULTS: There were significant differences in PSQI subscale scores of the quality, latency, duration, efficiency, disturbances of sleep, and global PSQI scores among subjects in the three groups before and after interventions. Furthermore, there was a significant reduction in the frequencies of nocturnal awakening and night wakeful time in the acupressure group compared to the other two groups. CONCLUSIONS: This study confirmed the effectiveness of acupressure in improving the quality of sleep of elderly people and offered a nonpharmacological therapy method for sleep-disturbed elderly people.

Acupressure↗
PubMed1999

Detection of PAX3-FKHR and PAX7-FKHR fusion transcripts in rhabdomyosarcoma by reverse transcriptase-polymerase chain reaction using paraffin-embedded tissue.

BACKGROUND: Alveolar rhabdomyosarcoma (RMS) is associated with a characteristic chromosomal translocation t(2;13)(q35;q14). The genes involved in this translocation are paired box (PAX)3 on chromosome 2 and forkhead in RMS (FKHR) on chromosome 13. An occasional variant translocation t(1;13)(p36;q14) affecting PAX7 and FKHR on chromosomes 1 and 13, respectively, has also been described. Chromosomal translocations in RMS are detected using conventional cytogenetic analysis, fluorescence in situ hybridization (FISH) or reverse transcriptase-polymerase chain reaction (RT-PCR) on fresh or frozen tissue samples. We describe the results of RT-PCR analysis of PAX3-FKHR and PAX7-FKHR chimeric messages in formalin-fixed, paraffin-embedded tissue samples from 17 RMS cases. METHODS: RNA was extracted from formalin-fixed, paraffin-embedded RMS tissue. Oligonucleotide primers corresponding to the regions of PAX3, PAX7 and FKHR were used for the detection of PAX3-FKHR and PAX7-FKHR chimeric messages. A seminested PCR of the PCR products was used to increase the sensitivity of detection. The amplified fragments were purified and directly sequenced to confirm the specificity of the methods. RESULTS: The PAX3-FKHR chimeric message was detected in all three cases of alveolar RMS but not in any of the 12 embryonal and two pleomorphic RMS cases. The PAX7-FKHR fusion transcript was detected in one case of embryonal RMS. CONCLUSIONS: The results indicate that the RT-PCR assay is a reliable method for the detection of the PAX3-FKHR fusion transcript of alveolar RMS in formalin-fixed, paraffin-embedded tissue. This simple method enables pathologists to identify chromosomal rearrangements in RMS as a diagnostic aid in cases where fresh or frozen tissue is not available.

DNA-Binding Proteins↗
PubMed1999

Longitudinal analysis of methicillin-resistant Staphylococcus aureus isolates at a teaching hospital in Taiwan.

In Taiwan, the frequency of nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has increased rapidly during the past 10 years. To investigate the epidemiology of MRSA infections, a total of 140 MRSA isolates collected at National Taiwan University Hospital from 1992 to 1996 were characterized by pulsed-field gel electrophoresis (PFGE) profiles and antibiotypes, as determined with the disk diffusion method. Among these isolates, six PFGE types (with 20 subtypes) and six antibiotypes were identified. Antibiotyping proved to be a poor method of epidemiologic analysis, because almost all of the MRSA isolates analyzed shared a very similar multidrug-resistant antibiotype. Most MRSA infections and colonizations in this hospital were due to the spread of strains belonging to three major PFGE types (A, B, and C). However, the major type changed in different years with types A, B, and C being predominant in 1992 through 1993, 1994 through 1995, and 1996, respectively. The three major PFGE types spread easily throughout the hospital wards, presumably carried by health care workers and environmental contamination. Our results demonstrate that there was a dominant strain spreading in our hospital each year and the dominant strain may shift in different years.

Bacterial Typing Techniques↗
PubMed1999

Enhancement of radiosensitivity in human glioblastoma U138MG cells by tetrandrine.

Tetrandrine, a natural lipid-soluble alkaloid with a low molecular weight, has both anti-tumor activity and a tissue-protective effect, as demonstrated in our previous studies. We studied tetrandrine to determine whether or not it enhanced radiosensitivity in human glioblastoma U138MG cells. Tetrandrine at concentration of 5.0 and 7.5 eg/ml dramatically enhanced the growth-inhibiting effect of radiation. This effect is dose-dependent on the dose of both tetrandrine and radiation. Moreover, we found that tetrandrine eliminated the cell cycle perturbation induced by radiation. Cells treated with tetrandrine alone as well as with a combination of tetrandrine and radiation became rounded, floated up and grew sparsely under observation under an inverted light microscope, DNA fragmentation was also noted by gel electrophoresis. These findings suggest that tetrandrine has potential as an adjunct to radiotherapy for glioblastoma.

Alkaloids↗
PubMed1998

A conserved sequence block in murine and human T cell receptor (TCR) Jalpha region is a composite element that enhances TCR alpha enhancer activity and binds multiple nuclear factors.

A conserved sequence block (CSB) located in a noncoding region of the mouse and human TCR alpha/delta loci, showing six differences over 125 nucleotide positions (95% similar), was subjected to detailed analyses in this study. Transient transfection results showed that the CSB-containing element in conjunction with the TCR alpha enhancer up-regulated the alpha enhancer activity, whereas no enhancer activity was detected when CSB alone was assayed. In vitro occupancy analyses of CSB by nuclear factors reveal the existence of an unexpectedly intricate network of CSB-protein and protein-protein interactions. Lymphoid-specific as well as T-lineage-specific nuclear factors are involved to differentially form CSB-bound complexes in extracts of various tissues and cell lines. Liver was shown to contain factor(s) sequestering thymic CSB-binding factors. Furthermore, the putative binding sites for transcription factors known to be important for lymphoid-lineage development are present in CSB and are targeted by nuclear factors. On the basis of these results, we propose that the CSB element may play a role in shaping the chromatin structure by which the accessibility of TCR alpha/delta loci to the recombinase complex and/or to the transcriptional apparatus can be controlled.

Animals↗
PubMed1998

Spatial variations of airborne particles in metropolitan Taipei.

During the summer and fall of 1991, total (TSP) and PM10 measurements were conducted at several sites simultaneously to evaluate the spatial variation of particle pollution in Taipei. Eighty-four samples were obtained from high-, medium- and low-polluted areas of the city. PM10 levels on roadside, sidewalk and covered walkways near a main road were 527.8 micrograms/m3, 466 micrograms/m3 and 477 micrograms/m3, respectively; the concentrations were not significantly different horizontally away from the emission sources. The PM10 concentrations on the second, seventh and 14th floors of a building were 305.31 micrograms/m3, 178.3 micrograms/m3 and 168.7 g/m3, respectively; the highest was on the second floor, but concentrations did not diminish from the seventh to the 14th floor. In addition, PM10 concentrations on the main street, side street and alley of an area were 155.3 micrograms/m3, 267.7 micrograms/m3 and 167.1 micrograms/m3, respectively; the highest concentration appeared on the side street. Furthermore, high fractions of PM10 in TSP mass were 90%, 84% and 79% for the high-, medium- and low-polluted areas. The percentages that exceed the US PM10 standard of 150 micrograms/m3 for the high- and medium-polluted areas were 100% and 71% and their exceedance was substantial. Therefore actions to mitigate the emission sources need to be fortified.

Air Pollutants↗
PubMed1998

Application of "one-bead one-compound" combinatorial library methods in signal transduction research.

Using a "split-synthesis" solid phase synthetic approach, bead libraries can be generated such that each bead displays only one chemical entity. This "one-bead one-compound" combinatorial library can then be assayed for specific biological properties using either a solid-phase on-bead binding or functional assay, or a releasable solution phase assay. Positive compound-beads can then be isolated for structure determination. Various assay systems to screen such a "one-bead one-compound" library are described. We have used this combinatorial library method to discover peptides that bind to the cell surface immunoglobulins of murine lymphoma cells. Such peptides, when presented in an oligomeric form to a lymphoma cell are able to induce signal transduction. Additionally, we have also applied the "one-bead one-compound" combinatory library approach to elucidate peptide substrate motifs for protein tyrosine kinases. Multiple distinct peptide motifs were identified for p60(c-src) protein tyrosine kinase. Using the identified peptide substrates as templates, potent and highly specific pseudosubstrate-based peptide inhibitors were developed.

Animals↗
PubMed1998

Structural requirements and ionic mechanism of the Mytilus inhibitory peptides (MIPs) on Helix central neurons.

1. The structural and ionic requirements for potent FVamide-induced inhibition were investigated using Helix aspersa central neurons under current or voltage clamp. 2. For potent FVamide inhibition the full hexapeptide sequence, GSPYFVamide, was required. The rank order of decreasing potency was GSPYFVamide >> SPYFVamide> PYFVamide > YFVamide. 3. GSPYFVamide inhibition involved an increase in conductance to both potassium and chloride ions as demonstrated by ion substitution experiments and addition of 4-aminopyridine, tetraethylammonium, 4,4-di-isothiocyanatostilbene-2,2'-disulfonic acid, 4,4-dinitrostilbene-2,2'-disulfonic acid disodium salt and furosemide to the solution bathing the preparation.

Animals↗