Biomedical subjects

C Y Chen

Publications and source records attributed to C Y Chen.

At least 91 records · Page 5Linked to original sources

PubMed2001

Organ system failures prediction model in intensive care patients with acute renal failure treated with dialysis.

OBJECTIVE: To evaluate the organ system failures hospital mortality predictions in critically ill patients with acute renal failure requiring dialysis. DESIGN: Prospective, cohort study. SETTING: Intensive care units in a tertiary care university hospital in Taiwan. PATIENTS: A total of 112 patients admitted to the intensive care units with acute renal failure who required dialysis from January 1999 through December 1999. INTERVENTIONS: Collection of information necessary to compute the number of failed organs. MEASUREMENTS AND RESULTS: Of the 112 patients studied, 75 were men and 37 were women. The mean age of survivors and non-survivors was 58.59 +/- 19.91 years and 58.76 +/- 19.62 years. The overall mortality rate was 67%. There were no significant differences between survivors and non-survivors in terms of age, gender, or indication for dialysis. The cause of death in the majority of patients was related to organ system failure during the 24 hours immediately preceding the initiation of acute hemodialysis, and carry mortality rates exceeding 83% with the coexistence of four or more failed organs. The area under the organ system failures prediction model receiver operating characteristic curve equaled 0.772 +/- 0.046. CONCLUSION: We conclude that mortality rate for acute renal failure in intensive care unit patients continues to be high. Organ system failures prediction model performed well and simple in its ability to identify patients who die in hospital. Mortality rate increases as number of failed organ increases.

Acute Kidney Injury↗

PubMed2001

Monoclonal and polyclonal antibodies against human ferritin, a nonspecific tumor marker.

The aim of this study was to produce monoclonal and polyclonal antibodies against a nonspecific tumor marker, human ferritin. Hyperimmune ICR mice produced polyclonal antibodies after injection with 0.5 mL pristane, and were injected with NS-1 myeloma cells 2 weeks later. Hyperimmune Balb/c mice were used for the production of monoclonal antibodies (MAbs). Mice were immunized four times, given a final boost, and their spleen cells were collected and fused with NS-1 myeloma cells under the presence of PEG 1500. The fused cells were then selected in the HAT-RPMIX medium. Anti-ferritin antibody-secreting hybridoma cell lines with high titer were cloned by enzyme-linked immunoadsorbent assay (ELISA) and then subcloned by limiting dilution in 15% fetal bovine serum (FBS) HT-RPMIX medium. Five murine hybridoma-producing antiferritin MAbs were obtained and designated 1AD11F9, 1AD11E11, 2AD11D2, 2AD11A5, and 3AD11G8. Isotypes of these MAbs were identified as IgM heavy chain and kappa light chain. Hitrap Protein A and Hitrap IgM purification column were used for the purification of polyclonal and monoclonal antibodies, respectively.

Animals↗

PubMed2001

Stability-indicating high-performance liquid chromatographic assay method and photostability of carprofen.

A rapid, sensitive, and accurate stability-indicating high-performance liquid chromatographic assay method for determining the degradation of carprofen (CPF) is developed and validated under acidic, basic, or photo-irradiated conditions. The analysis is monitored with a Cosmosil 5C18-AR column using a mobile phase of CH3CN-H2O-AcOH (50:49:1, v/v/v) at 260 nm. The developed method satisfies the system suitability criteria, peak integrity, and resolution among the parent drug and its degradation products. The results indicate that the established assay method shows good selectivity and specificity suitable for stability measurements of CPF. CPF is found to be more sensitive to exposure to light and in acidic conditions, but it is stable in a basic medium. The kinetic study of the photodegradation of CPF follows an apparent first-order reaction in a variety of solvents. The solvent effects on the rates of degradation are in the decreasing order of chloroform > dichloromethane > methanol > ethanol > 2-propanol, which is irrelevant to the dielectric constant epsilon. However, the hydrogen-donating ability of the solvents is essential to the photochemical decomposition of CPF. A plot of log k versus the Kirkwood function exhibits a linear relationship in aqueous ethanolic solutions, which implies that degradation proceeds via an ionic mechanism.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Chronic hepatitis C virus infection associated with primary warm-type autoimmune hemolytic anemia.

Autoimmune hematologic abnormalities are not well recognized in chronic hepatitis C virus infection. We demonstrate an unusual association between primary autoimmune hemolytic anemia and chronic hepatitis C virus infection. A 69-year-old woman who had a history of hepatitis C virus-related liver cirrhosis was found to have deteriorating anemia with reticulocytosis when admitted to the hospital. Laboratory work revealed both positive direct and indirect Coombs' tests, and warm-type immunoglobulin G against surface antigens of red blood cells. After prednisolone therapy, her anemia improved dramatically. To our knowledge, this is the first reported case of chronic hepatitis C virus infection linked with autoimmune hemolytic anemia in its natural course, not related to prior interferon treatment. Our report suggests that isolated autoimmune hemolytic anemia may be one of the unusual hematologic manifestations of chronic hepatitis C virus infection.

Aged↗

PubMed2001

Treatment of distal clavicle fracture using Kirschner wires and tension-band wires.

BACKGROUND: Nonunion frequently follows distal clavicle fracture. Traditional pinning methods using the through acromioclavicular articulation may result in osteoarthritic changes or ankylosis. This study introduces a direct pinning technique in which the acromioclavicular joint is spared. METHODS: Twelve patients with displaced distal clavicle fractures received open reduction and fixation with Kirschner wires (K-wires) and tension-band wires, from May 1996 to March 1997. The indication for surgery was type IIa fracture or fracture with displacement. Unrestricted passive and active range of motion was performed as soon as possible after the operation. Stretching and exertional exercises were permitted after radiographs showed an osseous union and after the implants were removed. RESULTS: Eleven patients achieved osseous union with painless full motion. Union time ranged from 3 to 6 months. One patient suffered from more comminuted fracture because of a fall 2 months after operation. This patient received a revision surgery with distal clavicle resection and coracoclavicle reconstruction. Symptomless ossification around the coracoclavicle ligament was noted on radiographs in one patient. The ossification did not progress after the 9-month follow-up. CONCLUSION: Edwards reported a rate of 45% delayed union and 30% nonunion in type II fractures. Several techniques had been described in the relevant literature. In our practice, fixation with Kirschner wires and tension-band wires has been successful in the treatment for displaced distal clavicle fracture.

Accidental Falls↗

PubMed2001

The impact of allergies and allergy treatment on worker productivity.

Allergic disorders are a chronic and highly prevalent condition in the general population and the workforce. Their effect on workers and corporate costs go beyond the direct cost of treatment, as the condition can lower a worker's productivity. Previous research includes estimates of the decrease in productivity associated with allergic disorders. None of these studies, however, offered an objective measure of how worker productivity is affected by allergic disorders. In the present study, the productivity of telephone customer service representatives suffering from allergic disorders is examined before, during, and after the ragweed pollen season. In addition, these workers were surveyed as to the type of medication they used in response to their condition. A significant correlation was observed between an increase in pollen counts and a decrease in productivity for workers with allergies. Compared with workers without allergies, employees with allergies who reported using no medication showed a 10% decrease in productivity. No differences were observed among workers with allergies using different types of medications, although the medication groups had significantly higher productivity than the no-medication group. The expected lowered productivity of those workers with allergies who used sedating antihistamines may have been offset by their relatively lower level of symptom severity and by the nature of the job and the productivity measures used.

Absenteeism↗

PubMed2001

Bank One's worksite-based asthma disease management program.

Non-occupational asthma is a common disease affecting approximately 6% of the US population. Asthma accounts for an estimated 3 million workdays lost each year in the United States and for reduced employee job productivity. Although asthma disease management programs are relatively common in managed care organizations, they generally have not been offered at the workplace. A total of 168 employees with asthma were identified, and 76 participated in a worksite asthma disease management program. Of them, 41 (53.9%) completed an Asthma Therapy Assessment Questionnaire (ATAQ) at baseline, post-program (2 months), 4 months, and 12 months. The total ATAQ Index declined from 3.59 at baseline to 2.76 at 12 months (p < 0.01). After the program, significantly more employees reported using controller medications (the desired behavior) rather than reliever medications. A worksite-based disease management program for asthma should reduce medical care costs and absenteeism and improve worker productivity.

Adult↗

PubMed2001

New tests for syphilis: rational design of a PCR method for detection of Treponema pallidum in clinical specimens using unique regions of the DNA polymerase I gene.

A sensitive and specific PCR method to detect Treponema pallidum in clinical specimens was developed. PCR primers were designed based on two unique features of the DNA polymerase I gene (polA). The first distinctive characteristic is that the region codes for a high cysteine content and has low homology with similar regions of DNA polymerase I gene from known microorganisms. The second unique feature is the presence of four insertions in the gene. PCR tests using primers designed on the basis these regions reacted with various pathogenic T. pallidum subspecies but did not react with nonpathogenic treponemal species or other spirochetes. An additional 59 species of bacteria and viruses, including those that cause genital ulcers, tested negative. This PCR method is extremely robust and sensitive. The detection limit is about 10 to 25 organisms when analyzed on gel. However, the analytic sensitivity can be increased by at least 1 log, to a detection limit of a single organism, when the ABI 310 Prism Genetic Analyzer is used to detect fluorescence-labeled amplicons. We further used this test in a clinical setting and compared the results with results from a previously reported multiplex-PCR test (for T. pallidum, Haemophilus ducreyi, and herpes simplex virus). We tested 112 genital ulcer specimens by the polA PCR, obtaining a sensitivity of 95.8% and a specificity of 95.7%. These results suggest that the polA PCR is applicable as a routine clinical diagnostic test for syphilis.

Amino Acid Sequence↗

PubMed2001

Versatile role for hnRNP D isoforms in the differential regulation of cytoplasmic mRNA turnover.

An important emerging theme is that heterogeneous nuclear ribonucleoproteins (hnRNPs) not only function in the nucleus but also control the fates of mRNAs in the cytoplasm. Here, we show that hnRNP D plays a versatile role in cytoplasmic mRNA turnover by functioning as a negative regulator in an isoform-specific and cell-type-dependent manner. We found that hnRNP D discriminates among the three classes of AU-rich elements (AREs), most effectively blocking rapid decay directed by class II AREs found in mRNAs encoding cytokines. Our experiments identified the overlapping AUUUA motifs, one critical characteristic of class II AREs, to be the key feature recognized in vivo by hnRNP D for its negative effect on ARE-mediated mRNA decay. The four hnRNP D isoforms, while differing in their ability to block decay of ARE-containing mRNAs, all potently inhibited mRNA decay directed by another mRNA cis element that shares no sequence similarity with AREs, the purine-rich c-fos protein-coding region determinant of instability. Further experiments indicated that different mechanisms underlie the inhibitory effect of hnRNP D on the two distinct mRNA decay pathways. Our study identifies a potential mechanism by which cytoplasmic mRNA turnover can be differentially and selectively regulated by hnRNP D isoforms in mammalian cells. Our results support the notion that hnRNP D serves as a key factor broadly involved in general mRNA decay.

3T3 Cells↗

PubMed2001

Biological basket weaving: formation and function of clathrin-coated vesicles.

There has recently been considerable progress in understanding the regulation of clathrin-coated vesicle (CCV) formation and function. These advances are due to the determination of the structure of a number of CCV coat components at molecular resolution and the identification of novel regulatory proteins that control CCV formation in the cell. In addition, pathways of (a) phosphorylation, (b) receptor signaling, and (c) lipid modification that influence CCV formation, as well as the interaction between the cytoskeleton and CCV transport pathways are becoming better defined. It is evident that although clathrin coat assembly drives CCV formation, this fundamental reaction is modified by different regulatory proteins, depending on where CCVs are forming in the cell. This regulatory difference likely reflects the distinct biological roles of CCVs at the plasma membrane and trans-Golgi network, as well as the distinct properties of these membranes themselves. Tissue-specific functions of CCVs require even more-specialized regulation and defects in these pathways can now be correlated with human diseases.

Adaptor Proteins, Vesicular Transport↗

PubMed2001

Time course of cerebral infarction in the middle cerebral arterial territory: deep watershed versus territorial subtypes on diffusion-weighted MR images.

PURPOSE: To examine possible differences between the evolution of cerebral watershed infarction (WI) and that of territorial thromboembolic infarction (TI) by using diffusion-weighted (DW) and T2-weighted magnetic resonance (MR) images and apparent diffusion coefficient (ADC) maps. MATERIALS AND METHODS: Fourteen patients with TI and nine with WI underwent MR imaging from the acute to chronic infarction stages. ADC maps were derived from DW images. Lesion-to-normal tissue signal intensity ratios on ADC maps (rADC), echo-planar T2-weighted images, and DW images were calculated. Lesion volumes at acute or early subacute infarction stages were measured on DW images, and final lesion volumes were estimated on fluid-attenuated inversion-recovery images. RESULTS: Analysis of variance revealed a significant difference in temporal evolution patterns of rADC between WI and TI (P <.001). rADC pseudonormalization following TI began about 10 days after symptom onset, but that following WI did not occur until about 1 month after symptom onset. The Pearson correlation coefficient between final and initial infarct volumes was 0.9899 for both infarction subtypes, indicating that the initial ischemic injury volume measured at the acute or early subacute stage predicted the final lesion volume fairly well. CONCLUSION: The evolution time of ADC is faster for TI than for WI. This difference, which likely originates from the different pathophysiologic and hemodynamic features of the two infarction types, might account for the relatively large range of ADC values reported for the time course of ischemic strokes.

Acute Disease↗

PubMed2001

The pharmacological effect of omeprazole on water gastric emptying: A study based on an impedance measure.

The present study was performed to validate the accuracy of a self-designed applied-potential tomograph (APT) in measuring the cross area of a studied object and to assess the effect of omeprazole premedication on water gastric emptying (GE), based on APT. Twelve electrodes were evenly placed in a circular array around the studied subjects. Ten electrodes in a rotated order recorded the electrical current injected into paired electrodes. Based on tomography, averaged signals of changed resistivity were constructed to display the area of interest and GE curve. Six beakers of various diameters were respectively placed into a cylindrical perspex tank which was filled with saline to measure their cross areas via computer-generated diagrams of APT. One hour after either omeprazole (20 mg) or placebo premedication, 15 healthy males were ordered to consume 500 ml of test water to assess emptying for 40 min. Within 3 days, a similar procedure was repeated using the counterpart premedication. The true cross areas of the 6 beakers are 2.01, 15.9, 18.8, 30.19, 38.48 and 63.61 cm(2), whereas those obtained by APT were 7.9 +/- 2.9, 16.7 +/- 3.3, 22.4 +/- 4.9, 28 +/- 4.8, 48.7 +/- 7.6 and 67 +/- 6.1 cm(2), respectively (r = 0.98, p < 0.001). Valid emptying data were obtained in 73.3 and 86.6% of subjects, following placebo and omeprazole, respectively (not significant). The half emptying times were 12.7 +/- 5.1 min for the placebo-treated group and 10.5 +/- 3.6 min for the omeprazole-treated group, respectively (p < 0.05). The areas under the emptying curve were 1,611.5 +/- 357.6 and 1,317.3 +/- 316.7 arbitrary units, respectively (p < 0.01). In conclusion, our APT system is accurate for large-area measurements; acid inhibition before APT measurement does not increase the success rate but enhances water emptying. The interpretation of impedance-obtained GE should consider the acid-inhibitory effect.

Adult↗

PubMed2001

Failure of grommet insertion in post-irradiation otitis media with effusion.

Nasopharyngeal carcinoma (NPC) survivors with post-irradiation otitis media with effusion (OME; 100 ears) were divided into 2 groups. One group underwent grommet insertion, and the other group was treated by repeated myringotomies plus aspiration to evaluate the outcome of the OME. Computed tomography, magnetic resonance imaging, audiometry, and local checks of the ear, nose, and nasopharyngeal fields were performed to evaluate the sinus and middle ear conditions over a long-term (more than 10 years) follow-up period. The results in these NPC survivors with OME indicated that the prevalence of middle ear complications in the myringotomized group (33%) was less than that in the grommeted group (90%). Grommets alone cannot eradicate inflammation outside the middle ear cavity, but rather, they can aggravate it by superinfection. We therefore recommend that controlling the radiation-induced inflammation in areas such as the ears, nose, sinuses, and nasopharynx is most important. In conclusion, post-irradiation OME should be treated in a different way from conventional OME. Restated, grommet insertion is contraindicated in post-irradiation OME.

Adult↗

PubMed2001

Lung C-fiber CNS reflex: role in the respiratory consequences of extended environmental tobacco smoke exposure in young guinea pigs.

Environmental tobacco smoke (ETS) exposure harms the respiratory health of children and is associated with an increased risk of asthma and sudden infant death syndrome (SIDS). The mechanisms by which ETS causes these effects are not understood. We hypothesized that one mechanism is an upregulation of the lung C-fiber central nervous system (CNS) reflex responses, which would result in exaggerated reflex responses of apnea, bronchoconstriction, and mucous hypersecretion. The purpose of this work is to highlight evidence obtained in an animal model of postnatal ETS exposure supporting the hypothesis and present data suggesting that actions of the neuropeptide substance P in the nucleus tractus solitarius (NTS) may contribute. Exposing young guinea pigs to sidestream smoke, the surrogate for ETS, for 5 weeks during the equivalent of human childhood, increased the excitability of afferent lung C fibers and NTS neurons in the CNS reflex pathway and prolonged the expiratory apnea. The findings suggest that an increased excitability of NTS neurons that can augment reflex output may contribute to respiratory symptoms in children exposed to ETS. Besides ETS exposure, substance P can also excite NTS neurons and augment lung C-fiber CNS reflex responses. Others have shown that substance P synthesis in lung C fibers is upregulated by another environmental stimulant, allergen. Thus, an upregulation of the substance P system at NTS synapses could contribute to the increased NTS excitability and enhanced reflex responses to lung C-fiber stimulation, providing a potential mechanism to help explain the association of ETS exposure with respiratory symptoms and SIDS.

Animals↗

PubMed2001

Acute flaccid paralysis in infants and young children with enterovirus 71 infection: MR imaging findings and clinical correlates.

BACKGROUND AND PURPOSE: Enterovirus 71 (EV71) infection is now considered an important cause of childhood acute flaccid paralysis. The purpose of our study was to determine whether EV71-infection-related acute flaccid paralysis in infants and young children has characteristic MR imaging patterns. METHODS: Seven infants and young children with acute paralysis of the upper or lower extremities and positive EV71 cultures underwent spinal MR studies during an outbreak of hand-foot-and-mouth disease in Taiwan in 1998. RESULTS: Acute paralysis was observed in one upper extremity in two patients, in one lower extremity in three patients, and in both lower extremities in two patients. None of the patients had sensory impairment or bulbar palsy. MR studies showed unilateral or bilateral hyperintense lesions in the anterior horn regions of the cord on T2-weighted images in six patients. No abnormal signal was present in one patient. Two of three patients who received intravenous injections of contrast material had ventral root enhancement on T1-weighted images. One of them also had enhancement of the unilateral anterior horn cells. At clinical follow-up, both patients with bilateral anterior horn abnormalities had residual motor weakness, whereas only one of the five patients with unilateral involvement had residual weakness. CONCLUSION: EV71 radiculomyelitis tends to be unilateral and to specifically involve both the anterior horn cells of the cord and the ventral roots. MR imaging allows early detection of spinal cord and root lesions.

Acute Disease↗

PubMed2001

A common precursor for the three subunits of L-glutamate oxidase encoded by gox gene from Streptomyces platensis NTU3304.

A segment of DNA containing the L-glutamate oxidase (gox) gene from Streptomyces platensis NTU3304 was cloned. The entire nucleotide sequence of the protein-coding portion consisting of 2130 bp (710 codons, including AUG and UGA) of the cloned DNA fragment was determined. The gox gene contained only one open reading frame (ORF) which coded for a 78-kDa polypeptide, the precursor of active extracellular Gox. Mature Gox is composed of three subunits, designated as alpha, beta, and gamma, with molecular masses of 39, 19, and 16 kDa, respectively. Analyses of the N-terminal amino acid sequences of the subunits revealed that the order of subunits in the precursor polypeptide encoded by the ORF, from N-terminus to C-terminus, is alpha-gamma-beta. The presence of the flavin adenine dinucleotide (FAD)-binding motif place Gox as a member of the flavoenzyme family. Furthermore, a negative effect of glucose on the biosynthesis of Gox was observed when it was used as carbon source.

Amino Acid Oxidoreductases↗

PubMed2001

Statistical comparisons of the no-observed-effect concentration and the effective concentration at 10% inhibition (EC10) in algal toxicity tests.

Batch-type algal toxicity tests were conducted to evaluate the low toxic effects of metal toxicants. Both the no-observed-effect concentration (NOEC) and the effective concentration at 10% inhibition (EC10) were calculated and compared. The results of this study indicate that, for algal toxicity tests, NOEC offers better protection to the test organisms than EC10. In addition, the consistency of NOEC is found to depend on the response endpoints measured. A cut-off-value approach is proposed to determine whether NOEC or EC10 should be chosen for estimating low toxic effects. For a specific toxicity test, the average cut-off value directly indicates the magnitude of the square root of the within-group-variance. A precise test associated with small within-group-variances also produces relatively small average cut-off value (say, less than 10% of the growth reduction). This average value provides useful information on the minimum protection that can be offered by the NOEC.

Dose-Response Relationship, Drug↗

PubMed2001

Langerhans' cell histiocytosis presenting with a para-aortic lesion and heart failure.

Langerhans' cell histiocytosis (LCH) is an uncommon disease with variable manifestations. We report a case of LCH with the unusual initial presentations of chest pain and progressive heart failure in a 5-year-old boy. Chest radiography revealed a wide mediastinum with cardiomegaly. Electrocardiography showed first-degree atrioventricular block and an inverted T wave over V4-V6. Echocardiography, computed tomography, and magnetic resonance imaging of the chest all showed an infiltrating lesion that enveloped the entire heart, great vessels, and coronary arteries. Pathologic examination of the biopsy specimen revealed LCH. Chemotherapy, which included prednisolone, vincristine, methotrexate, and 6-mercaptopurine, had only a minimal effect on the tumor. After the addition of etoposide, the lesion decreased in size, and the symptoms and signs of heart failure and chest pain were ameliorated.

Aortic Diseases↗