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Biomedical subjects

C Y Chen

Publications and source records attributed to C Y Chen.

At least 127 records · Page 7Linked to original sources
PubMed2000

Cloning and characterization of the replicon of the Nocardia italica plasmid, pNI100.

A 19-kb plasmid, pNI100, was isolated from Nocardia italica CCRC12359; its replicon was cloned and characterized as having a single open reading frame (ORF) of 1188 bp specifying 396 amino acids (aa). Analyses of the deduced aa sequence of the Rep protein indicated that characteristics of three consensus sequences and a P-loop-like motif in the Rep protein of plasmid pSG5, a conjugative plasmid involving a rolling-circle replication mechanism, were conserved in those of plasmid pNI100. Phenotypically, a pock structure was produced in the regenerated mycelium by introducing pNI100 DNA into the Streptomyces lividans protoplast. This result strongly suggests that pNI100 is a conjugative plasmid and probably replicates by a rolling-circle replication mechanism. By using the replicon of pNI100, a bifunctional plasmid pNI105 that could replicate in both Escherichia coli and S. lividans was constructed and found to be a useful cloning shuttle vector.

Amino Acid Sequence↗
PubMed2000

MRI in acute neuropathic Gaucher's disease.

We present the cranial MRI findings in a 6-month-old girl with biopsy-proven acute neuropathic Gaucher's disease, which include unilateral cerebral atrophy and dural thickening with contrast enhancement.

Acute Disease↗
PubMed2000

Lymphoma of bone with initial presentation as a calvarial mass.

A 21-year-old man was examined for a right frontal skull mass that had been present for 4 months. Excision biopsy of the mass revealed diffuse large B-cell lymphoma. Subsequent studies showed right preauricular lymphadenopathy but no systemic involvement. The patient was treated with six courses of CHOP (cyclophosphamide, adriamycin, vincristine, and prednisolone) with adjuvant whole brain irradiation and achieved a complete remission.

Adult↗
PubMed2000

Cerebral dural sinus thrombosis in acute lymphoblastic leukemia with early diagnosis by fast fluid-attenuated inversion recovery (FLAIR) MR image: a case report and review of the literature.

Cerebral dural sinus thrombosis (CDST) is a very rare complication of acute lymphoblastic leukemia (ALL) in adult patients. A 23-year-old man with ALL developed dizziness, headache, diplopia, limb weakness, and a sensation of fullness in his head after his second induction chemotherapy with doxorubicin, prednisolone, and vincristine. Examinations of the peripheral blood, bone marrow, and cerebrospinal fluid showed no recurrent leukemic cells. Magnetic resonance (MR) imaging of the brain disclosed unexpected CDST at the left transverse sinus, which was seen only on the fast fluid-attenuated inversion recovery (FLAIR) sequence. His symptoms were relieved soon after treatment with heparin. MR imaging with FLAIR performed a second time 7 days later showed complete disappearance of the thrombosis. The patient was treated continuously with oral anticoagulant therapy and the symptoms did not recur. CDST can be diagnosed in its early phase by MR studies with FLAIR images. Anticoagulant therapy can be administered safely without precipitating the occurrence of infarction hemorrhage at such an early stage of CDST.

Adolescent↗
PubMed2000

Posterior cruciate ligament and coupled posterolateral instability of the knee.

We wanted to investigate the role of the posterior cruciate ligament (PCL) in the knee's posterolateral stability and the magnitude of the coupled posterolateral instability with the knee examined at 90 degrees of flexion. The coupled posterolateral instability of the knee was studied by selective ligament cutting in cadaver knees set at 90 degrees. The coupled posterolateral displacement after cutting the PCL was 173% of the intact knee. With an intact PCL, the coupled posterolateral displacement after cutting the popliteus tendon and lateral collateral ligament with the knee at 90 degrees of flexion was 299% of the intact knee. When the PCL was cut together with the popliteus tendon and lateral collateral ligament, the coupled posterolateral displacement was 367%. The PCL plays an important role in the posterolateral stability of the knee, and its injury may cause mild (< 5 mm) to moderate (5-10 mm) posterolateral instability. Thus, in a knee with posterolateral instability, injury of the PCL must be considered. With an intact PCL, the posterolateral instability was very recognizable with the knee at 90 degrees of flexion, and injury to the PCL further increased the posterolateral instability and caused posterior translation of the knee. Therefore, examination for posterolateral instability of the knee should also be performed with the knee at 90 degrees of flexion, which is much easier to perform in a clinical setting. A positive posterior translation rather than posterolateral instability at different knee positions differentiates knees with combined PCL and posterolateral instability from knees with isolated posterolateral instability.

Cadaver↗
PubMed2000

Non-tuberculous cold abscess of the psoas muscle--an unusual manifestation of colocutaneous fistula.

We report here a case of colocutaneous fistula drained from the retroperitoneal space mimicking a cold abscess of the psoas muscle. A 60-year-old diabetic woman with a 6-year history of a chronic draining sinus over her right thigh had been treated intermittently with antibiotics. At presentation, she had no systemic toxic signs nor other constitutional symptoms. The patient was inadequately managed by curettage at first under the tentative diagnosis of tuberculous cold abscess. After the correct diagnosis of colocutaneous fistula, right nephrectomy and right hemicolectomy with ileotransverse colostomy were done. The patient was well 5 years later without recurrence. This is an atypical presentation of enterocutaneous fistula in an immunodeficient patient that should be emphasized to facilitate the correct diagnosis and early treatment.

Colectomy↗
PubMed2000

Field evaluation of a passive sampler for the exposure assessment of 2-methoxyethanol.

OBJECTIVE: This paper presents a field evaluation of 3 M 3500 passive badges for measuring 2-methoxyethanol (ME) in a humid working environment. METHODS: A total of 93 pairs of side-by-side active/passive samples, 48 pairs of duplicate active samples, 52 pairs of duplicate passive samples, and three groups of six replicate active/passive samples were compared. Three groups of six replicate active charcoal/active charcoal tube with drying tube samples were also compared to evaluate the humidity effect. RESULTS: No statistical difference was found between the passive badges and active samplers. Linear regression showed the correlation to be high (r = 0.992, slope = 0.973, n = 93) over the range of 0.17-163 ppm. The mean concentration difference was -0.34 ppm and the mean relative error was 3.50%. The intraclass correlation coefficients of 48 duplicate active samples and 52 duplicate passive samples were 0.994 and 0.989, respectively. The precision of replicate passive, active, and active/drying tube samples (n = 6) were 3.84%, 7.14%, and 5.12%, respectively. CONCLUSIONS: The humidity effect for active samples was insignificant at the low sampling rate (36.3 ml/min). It is therefore concluded that the use of the passive samplers to assess ME exposure produces comparable findings to that of active sampling.

Environmental Exposure↗
PubMed2000

Prevalence and severity of symptoms in terminal cancer patients: a study in Taiwan.

This paper reports a prospective study conducted between September 1997 and July 1998 in 232 consecutive patients with terminal cancer. A structured data collection form was used daily to evaluate symptoms, which were analyzed at the time of admission, 1 week after admission and 48 h before death. Terminal cancer patients in this study were polysymptomatic. There were no statistically significant differences in the prevalence of most symptoms with the primary site of cancer. The majority of symptoms improved at the end of the 1st week after admission, but many symptoms worsened just before death. The high prevalence of symptoms and lack of significant difference among primary tumor sites may be related to shorter survival times caused by late referral, which is common in Taiwan.

Aged↗
PubMed2000

Distal stomach appears essential in the regulation of gastrointestinal transit.

Stomach and small bowel both influence gastrointestinal motility. We studied which portion of the stomach was essential for the regulation of gastrointestinal movement and determined the role of vasoactive intestinal polypeptide in this regulation. The study subjects consisted of 45 controls, 46 patients after subtotal gastrectomy, and 13 patients after total gastrectomy for stomach cancer. Orocecal transit time was measured, using the hydrogen breath test, to represent gastrointestinal movement, while plasma vasoactive intestinal polypeptide level was simultaneously assessed. The orocecal transit times in the study groups were (means +/- SD) 91.1 +/- 45.0, 57.1 +/- 34.3, and 60.8 +/- 34.8 min, respectively (P < 0.01). In the subtotal gastrectomy patients, age showed a negative correlation with orocecal transit time (r = -0.388; P < 0.01). In the total gastrectomy patients, no particular demographic factor influenced orocecal transit. Plasma vasoactive intestinal polypeptide levels in the three groups were 20.7 +/- 10.8, 22.7 +/- 10.9, and 20.6 +/- 9.1 pg/ml, respectively (NS). We conclude that both types of gastrectomies enhanced gastrointestinal movement, showing a similar effect, and that the distal stomach plus pylorus are most likely to exert an important inhibitory mechanism in the regulation of this movement. Vasoactive intestinal polypeptide is not a major peptide mediating this regulation.

Aged↗
PubMed2000

Synthesis, characterization and platelet adhesion studies of novel ion-containing aliphatic polyurethanes.

Two novel ion-containing aliphatic polyurethanes based on 4,4'-methylene dicyclohexyl diisocyanate (H12MDI), polytetramethyl oxide (PTMO) were synthesized using either sulfonated or carboxylated chain extender. The nonionic polyurethane chain extended with 1,4-butanediol, which is denoted as H-M-BD, was synthesized. Pellethane, a biomedical-grade polyurethane, was also studied for comparison. The polymer's bulk, surface, and platelet-contacting properties were studied using Fourier transform infrared spectrophotometry, differential scanning calorimetry, water absorption analysis, electron spectroscopy for chemical analysis, static contact angle analysis, and in vitro platelet adhesion experiments. The effects of ion incorporation on the morphology, surface properties and blood compatibility are discussed. Unlike MDI-based Pellethane, all H12MDI-based polyurethanes are not composed of crystalline hard segment domain but are amorphous. The ionic polyurethanes exhibit a smaller fraction of hydrogen-bonded carbonyl groups, poorer phase separation, smaller fraction of PTMO residing at the surface, and smaller contact angle; however, significant higher water absorption value than H-M-BD and Pellethane. The in vitro platelet adhesion experiments indicated that ion incorporation, especially for carboxylate, significantly reduced the number and the degree of activation of the adherent platelets.

Absorption↗
PubMed2000

Segment inertial properties of Chinese adults determined from magnetic resonance imaging.

OBJECTIVE: To improve the simulation of the task of manual materials handling for Chinese laborers, this study estimated the inertial properties of Chinese adults by using magnetic resonance imaging. DESIGN: Magnetic resonance imaging was used as a means of estimating inertial property. Following the estimation of inertial properties for the Chinese subjects, comparison between estimates for Chinese and Caucasian populations was made. BACKGROUND: Estimates of segment inertial properties are frequently based on data and procedures developed from human cadaver studies in which inertial properties have been measured directly. The errors might be derived from the utilization of the Caucasian data were questioned in our previous study on the spinal force prediction of the Chinese subjects during manual lifting. METHODS: Magnetic resonance images were scanned at a 20 mm interval from eight males aged 26 (S.D., 4) years. Tissues were differentiated and verified using adequate intensity thresholds on each slice, and the segmental volume and mass were integrated by slices. The moments of inertia for each segment were then determined about the anatomical axes using the parallel axis theorem.Results. Results showed that our estimates were close to the data derived by Dempster with a slight deviation. Larger percentages of mass were found in the upper arm (4.0%) and thigh (13.6%) than in previous studies. On the other hand, smaller moments of inertia about three axes were noted in the shank. CONCLUSION: Biomechanical modeling of the human body requires accurate prediction of body segment parameters that include measures of volume, mass, center of mass, and moments of inertia. This study suggests the need to estimate the inertial properties of segments from the Chinese population. Application of the data may improve the simulation of the task of manual materials handling for Chinese laborers in the future studies. RELEVANCE: Biomechanical modeling of the human body requires accurate prediction of body segment parameters that include measures of volume, mass, center of mass, and moments of inertia. To obtain the basic data of segment parameters for the Chinese adults, this study was proceeded with the magnetic resonance imaging technique.

Adult↗
PubMed2000

Belt effects on lumbar sagittal angles.

OBJECTIVE: The study examined the belt effects on the change of lumbar sagittal angles. DESIGN: The effects of pelvic and lumbar belts on lumbar sagittal angles were examined both radiographically and videographically in standing, erect sitting, and slump sitting. BACKGROUND: The resulting changes of lumbar angles when wearing belts with different mechanical characteristics should be different. METHODS: Eighteen healthy male subjects participated in this study. L1/L3, L3/L5, L5/S1 and L1/S1 were measured with the aid of lateral radiographs. The external joint angles were also measured via the motion analysis system. RESULTS: Radiographic data revealed an interactive effect between working posture and the use of a belt (P<0.046) on the change of L1/S1. In standing, both belts increased L1/S1 by increasing almost all the lumbar vertebral angles. In erect sitting, wearing lumbar belt had no effect but the pelvic belt decreased L1/S1 mainly through a decrease in L1/L3. In sitting slump with trunk flexion of 15 degrees, both belts increased L1/S1 and restricting the movement of the pelvis. CONCLUSIONS: Belt effect to the change of lumbar sagittal angles in posture which involve knee flexing and/or trunk flexing seems not as the same as in standing posture. RELEVANCE: This study related internal vertebral angles and externally measured trunk angles with lumbar and pelvic belt usage.

Adult↗
PubMed2000

DNA adduct level in lung tissue may act as a risk biomarker of lung cancer.

Lung cancer is a leading cause of mortality in Taiwan. We hypothesised that high susceptibility to DNA damage in the target organ acts as a risk biomarker for the development of lung cancer. To verify this hypothesis, the aromatic/hydrophobic DNA adduct levels of non-tumorous adjacent lung tissues from 73 primary lung cancer patients and 33 non-cancer controls were evaluated by 32P-postlabelling assay. Wilcoxon rank sum test showed that DNA adduct levels in lung cancer patients (49.58+/-33.39 adducts/10(8) nucleotides) were significantly higher than those in non-cancer controls (18.00+/-15.33 adducts/10(8) nucleotides, P<0.001). The DNA adduct levels among lung cancer and non-cancer samples were not influenced by smoking behaviour and cigarette consumption. Our data also showed that the polymorphisms of cytochrome P4501A1 (CYP1A1) Msp1, glutathione S-transferase M1 (GSTM1) and the combination of both genetic polymorphisms were not related to the DNA adduct levels. Interestingly, positive association between CYP1A1 protein expression and DNA adduct levels was found when CYP1A1 protein expression in lung specimens from lung cancer patients was examined by immunohistochemistry. Multivariate linear regression analysis indicated that the DNA adduct level was not associated with gender, smoking behaviour, or genetic polymorphisms of CYP1A1 and GSTM1. Moreover, multivariate logistic regression analysis showed that persons with high DNA adduct levels (>48.66 adducts/10(8) nucleotides) had an approximately 25-fold risk of lung cancer compared with persons with low DNA adduct levels (</=48.66 adducts/10(8) nucleotides). In conclusion, DNA adduct levels in lung tissue may be a more reliable lung cancer susceptibility biomarker than DNA adduct levels in leucocytes. In addition, higher susceptibility to DNA damage in lung cancer patients may partly play a role in the development of lung cancer.

Adenocarcinoma↗
PubMed2000

ent-kaurane diterpenoids from Annona glabra.

Three new kaurane diterpenoids, annoglabasin C (16alpha-acetoxy-ent-kauran-19-oic acid-17-methyl ester) (1), annoglabasin D (16alpha-acetoxy-ent-kauran-19-al-17-methyl ester) (2), and annoglabasin E (16alpha-hydro-19-ol-ent-kauran-17-oic acid) (3), and a new norkaurane diterpenoid, annoglabasin F (16alpha-acetoxy-19-nor-ent-kauran-4alpha-ol-17-methyl ester) (4), along with 13 known kaurane derivatives were isolated from the stems of Annona glabra. 16alpha-Methoxy-ent-kauran-19-oic acid (5) and 16alpha-hydro-ent-kauran-17,19-dimethyl ester (6) were obtained for the first time as natural products. The structures of compounds 1-6 were characterized by spectral analysis.

Diterpenes↗
PubMed2000

Cytotoxic constituents of Polyalthia longifolia var. pendula.

A new halimane diterpene, 3beta,5beta, 16alpha-trihydroxyhalima-13(14)-en-15,16-olide (1), and a new oxoprotoberberine alkaloid, (-)-8-oxopolyalthiaine (2), along with 20 known compounds, were isolated from a methanolic extract of Polyalthia longifolia var. pendula. The structures of compounds 1 and 2 were established by spectroscopic analysis. Several of these compounds were evaluated for cytotoxicity toward a small panel of human cell lines.

Alkaloids↗
PubMed2000

New alkaloids from Annona purpurea.

Three new alkaloids, promucosine (1), romucosine F (2), and romucosine G (3), along with 28 known compounds, were isolated from the MeOH extract of stems of Annona purpurea. The structures of 1-3 were determined on the basis of spectral data and chemical evidence.

Alkaloids↗
PubMed2000

New taxanes with an opened oxetane ring from the roots of Taxus mairei.

Two novel taxoids, taxumairols N (1) and O (2), have been isolated from extracts of the roots of Taxus mairei. The structures of 1 and 2 were identified as 7beta,9alpha,10beta,13alpha-tetraacetoxy-2alp ha, 4alpha,5alpha,20-tetrahydroxytax-11-ene and 7beta,9alpha,10beta, 13alpha-tetraacetoxy-1beta,2alpha,4alpha,5alp ha, 20-pentahydroxytax-11-ene on the basis of 1D and 2D NMR techniques including COSY, HMQC, HMBC, and NOESY experiments.

Magnetic Resonance Spectroscopy↗