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Biomedical subjects

R Y Chen

Publications and source records attributed to R Y Chen.

At least 37 records · Page 2Linked to original sources
PubMed2000

Progressive deterioration of soft neurological signs in chronic schizophrenic patients.

OBJECTIVE: Neurological signs are found to be increased in schizophrenia in cross-sectional studies. Whether they progress with time is an important issue in addressing the course of the illness. METHOD: The current study investigated different groups of neurological signs in 43 stable chronic schizophrenic patients over a 3-year period using an operationalized instrument. RESULTS: While symptoms and medication have remained largely unchanged in the 3-year period, significant increase in soft neurological signs (SNS) ('motor coordination', 'sensory integration' and 'disinhibition') has been observed. This contrasted with the stability of 'pyramidal', 'extrapyramidal', 'dyskinesia' and 'catatonia' signs. The increase in SNS appears not to be related to age, illness duration, symptoms or medication. CONCLUSION: This finding suggests that SNS represent a marker sensitive to a possible late deterioration process in the course of a schizophrenic illness.

Adult↗
PubMed2000

Verbal fluency in schizophrenia: reduction in semantic store.

OBJECTIVE: This is a study of the word production of patients with schizophrenia using a semantic verbal fluency task to address the unresolved issue of retrieval or storage impairment. METHOD: Twenty-one patients with schizophrenia and 11 matched healthy subjects performed a semantic verbal fluency task on 'food', 'animal' and 'transport' categories in Cantonese for 3 minutes each on five separate trials. RESULTS: Patients generated significantly fewer numbers of words compared with control on each trial. The estimated lexicon size of the patients was significantly smaller than that of the equivalent group. The amount of shared words and variable words generated in all five trials were reduced in the patient group. CONCLUSIONS: Our results suggest that poor verbal fluency in patients with schizophrenia may partly be attributable to reduction in semantic store. The importance of temporal lobe involvement on verbal fluency deficits needs to be emphasised as an integral part of the neurobiological basis of schizophrenia research.

Adult↗
PubMed2000

Results of laparoscopic fundoplication where atypical symptoms coexist with oesophageal reflux.

BACKGROUND: Laparoscopic Nissen fundoplication (LNF) has been increasingly performed for gastro-oesophageal reflux disease. The outcomes of LNF for patients with concurrent symptoms other than heartburn are unclear. The purpose of the present paper was to review the outcomes of LNF performed by one surgeon over 4 years and compare the outcomes of patients with reflux symptoms with those of patients having reflux symptoms plus atypical symptoms. METHODS: The records of a consecutive series of 90 patients were reviewed. Preoperative symptoms were defined as typical (heartburn and reflux) or atypical (other symptoms, e.g. cough, atypical chest pain, choking). At the time of follow up an independent observer interviewed patients, and collected data on current symptoms and patient satisfaction. A questionnaire of current symptoms and patient satisfaction was completed. A satisfaction score from 1 to 10 was given by patients, with 1 being very unsatisfied and 10 being very satisfied. RESULTS: Of the 90 patients, 97% had typical symptoms and 56% had concurrent atypical symptoms. Eighty-three of 90 patients were contacted; typical reflux symptoms improved in 95% of patients whereas atypical symptoms improved in only 54%. Overall, the mean satisfaction score was 8.7. Patients with atypical symptoms had a lower satisfaction score of 8.0 versus a satisfaction score of 9.0 for patients with only typical symptoms (P < 0.05). Patients with a satisfaction score < 8.0 had a higher rate of atypical symptoms (75%) than patients with a satisfaction score > or = 8 (50%). CONCLUSION: Laparoscopic Nissen fundoplication controlled typical reflux symptoms very well but atypical symptoms were improved in only approximately 50%. A lower satisfaction score was associated with preoperative atypical symptoms.

Adolescent↗
PubMed2000

[Phylogenetic study of Artemia from China using RAPD and AFLP markers].

We have applied the techniques of RAPD (random amplified polymorphic DNA) and AFLP (amplified fragment length polymorphism) to the analysis of the relationships among Artemia species and strains. RAPD markers were successfully employed to detect diversity and genetic differentiation among four species of brine shrimp: A. franciscana, A. urmiana, A. sinica, and A. parthenogenetica. Seventy, ten-base synthetic oligonucleotides were used to amplify a total of 458 distinct fragments. DNA polymorphisms were found in all the species examined; The highest percentage of polymorphic bands found in A. parthenogenetica, was 28.8 per cent. There are significant differences between bisexual sibling species and parthenogenetic populations. A. parthenogenetica provided 94 specific molecular markers, while bisexual sibling species gave 27 specific molecular markers. A. sinica is a species distinct from the other Old World bisexual species. AFLP were used to analyze 15 Artemia species and strains for genetic diversity. They are extremely sensitive to even a small sequence variation and more polymorphism than RAPD. Using only 10 pairs of primer combinations, we detected 580 AFLP bands of which were polymerphic. The RAPD and AFLP techniques are powerful DNA fingerprinting methods for classification of Artemia species and strains.

Animals↗
PubMed2000

[Studies on the chemical constituents of Murraya kwangsiensis].

AIM: To investigate the chemical constituents of Murraya kwangsiensis. METHODS: Compounds were isolated by silica gel column chromatography and TLC method, respectively. Structures of compounds were elucidated by spectral (UV, IR, MS, 1HNMR and 13CNMR) analysis. RESULTS: Five carbazole alkaloids and two other compounds were isolated and identified. Six of them are known compounds: murrayafoline A, murrayanine, koenine, isomahanine, palmitic acid and beta-sitosterol. One is a new alkaloid, named kwangsine. CONCLUSION: A new alkaloid, named kwangsine, was isolated from Murraya kwangsiensis Var. Six known compounds were isolated from this plant for the first time.

Alkaloids↗
PubMed2000

[Cloning of cancer-related genes of Rat6 fibroblasts by using an improved differential display method].

The p53 gene is the most frequently mutated gene identified so far in human cancers. When a mutant p53(135)-val gene was allowed to be over-expressed in Rat6(R6) cells, a high incidence of spontaneous transformation was observed in long-term culture of this cell line(R6 # 13-8). To identify genes involved in cell transformation, parental p53 over-expressing cell, R6 # 13-8, and its spontaneous transformant T2, were analyzed by an improved mRNA differential display technique, which was reproducible, simpler, and was able to clone cDNA longer than 500 bp, and was with less false positives. When 33 10-mer or 12-mer single primers with arbitrary but defined sequence were used for PCR, over 90 discrete cDNAs were obtained from R6 # 13-8 and T2 cells. Three differentially expressed cDNAs were identified, one of them is highly expressed in T2 cells, while the other two, 0.8 kb and 0.9 kb long, are highly expressed in R6 # 13-8 cells. The latter were cloned and confirmed by Northern hybridization. Both cloned fragment were not homologous with any published sequence. Our results suggest that the activation and inactivation of genes are involved in the process of the spontaneous transformation from R6 # 13-8 to T2.

Animals↗
PubMed1999

Calamistrins A and B, two new cytotoxic monotetrahydrofuran annonaceous acetogenins from Uvaria calamistrata.

Two new bioactive monotetrahydrofuran acetogenins, calamistrins A (1) and B (2), and two known compounds, uvarigrin (3) and uvarigranin (4), have been isolated from the roots of Uvaria calamistrata. The structures of the new compounds were elucidated by spectroscopic and chemical methods. The absolute stereochemistry of the stereogenic centers was established by Mosher ester methodology.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Styryllactones from the rhizomes of Goniothalamus griffithii.

Three new styryl-lactones 8-acetylgoniofufurone(1), 7-acetylgonio-pypyrone(3), and 5-acetylgoniopypyrone(4), along with ten known compounds, goniofufurone(2), goniopypyrone(5), goniothalamin, goniothalenol, (+)-isoaltholactone, goniodiol, 7-acetylgoniodiol, goniotriol, 8-acetylgoniotriol, 9-deoxygoniopypyrone were isolated from the rhizomes of Goniothalamus griffithii Hook f. et. Thoms. Their structures were elucidated by IR, MS, NMR spectra and chemical evidence. All compounds showed cytotoxic activities against human cancer cell lines.

Lactones↗
PubMed1999

New polyoxygenated cyclohexenes from Uvaria calamistrata.

Five new polyoxygenated cyclohexenes, named uvacalol A (1), B (2), C (3), D (4) and E (5) were isolated from the roots of Uvaria calamistrata. On the basis of spectral analysis and chemical derivatization, including the preparation of Mosher esters, the structures of compound 1-5 were established as (2R,3S,4R,5S)-2-acetoxyl-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene3,4-diol-3-benzoate, (2R,3S,4R,5S)-2-acetoxyl-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-3,4-diol-4-benzoate, (2R,3S,4R,5S)-5-ethoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-2,3,4-triol-3-benzoate, (2R,3S,4R,5S)-3-methoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-2,3,5-triol and (2R,3S,4R,5S)-2-acetoxyl-1-benzoyloxymethylcyclohex-1(6)-ene-3,4,5-triol-5-benzoate, respectively.

Alcohols↗
PubMed1998

Estimation of target hazard quotients and potential health risks for metals by consumption of seafood in Taiwan.

The purpose of this paper is to describe the impact of metal pollution on the main seafood and assess the potential health risk from consuming the contaminated seafood in Taiwan. The results of geometric mean (GM) metal concentrations in various seafood showed that the copper, zinc, and arsenic concentrations in oysters were significantly (p < 0.001) higher than those in the other seafood by about 1,057, 74.3, and 56.2 times, respectively. The green color found in the oysters was due to high GM copper and zinc concentrations of 909 (ranging from 113-2,805) and 1,293 (ranging from 303-3,593) microg/g dry wt, respectively. In addition, using a maximum consumption rate of 139 g/day of oysters for individuals, calculations yield target hazard quotients (daily intake/reference dose) of below 1 for cadmium and mercury and high values of 1.61, 9. 33, and 1.77 for inorganic arsenic, copper, and zinc in adults, respectively. The various lifetime cancer risks for inorganic arsenic (maximum exposed individuals risk ranging from 9.93 x 10(-6) to 3.11 x 10(-4)) might be caused by consuming different seafood in Taiwan. The highest risk estimate for inorganic arsenic was 5.10 x 10(-4) for consumption of oysters by Machu Islands residents. The long-term exposure of metals through consumption of oysters, especially for some high-risk groups, could be dangerous. Taking inorganic arsenic for example, a 10(-6) upper limit on lifetime risk as the health protection standard would require maximum oyster residue levels of approximately 0.0076-0.056 microg/g wet wt, for consumption rates of 139-18.6 g/d. In the light of known risks to public health, the government should issue an immediate warning to the public to refrain from eating all seafood harvested from the Taiwan coastal areas, especially the Hsiangshan area and the Machu Islands.

Environmental Exposure↗
PubMed1998

Linear acetogenins from Goniothalamus donnaiensis.

Four linear acetogenins, donhepocin (1), 34-epi-donhepocin (1'), donhexocin and donbutocin, have been isolated from the roots of Goniothalamus donnaiensis. 1 and 1', isolated as an epimeric pair, contain a rare gamma-hydroxymethyl-gamma-lactone. Their structures have been established on the basis of spectral and chemical evidence.

4-Butyrolactone↗
PubMed1998

Construction of a DNA library from chromosome 4 of rice (Oryza sativa) by microdissection.

A simple method to create a chromosome-specific DNA library of rice, including microdissection, amplification, characterization and cloning, is described. Rice chromosome 4 from a metaphase cell has been isolated and amplified by the Linker Adapter PCR (LA-PCR). The PCR products were labeled as probes with DIG-11-dUTP using the random priming method. Southern blot analysis with rice genomic DNA and specific RFLP markers demonstrated that the PCR products were derived from rice chromosome 4. A large library comprising over 100,000 recombinant plasmid microclones from rice chromosome 4 was constructed. Colony hybridization showed that 58% of the clones contained single or low-copy sequences and 42% contained repetitive sequences. The size of inserts generated by PCR ranged from 140bp to 500bp. This method will facilitate cloning of the specific chromosome DNA markers and important genes of rice.

Chromosome Mapping↗
PubMed1997

Neuropsychological correlates of sustained attention in schizophrenia.

We employed a simple and relatively undemanding task of monotone counting for the assessment of sustained attention in schizophrenic patients. The monotone counting task has been validated neuropsychologically and is particularly sensitive to right prefrontal lesions. We compared the performance of schizophrenic patients with age- and education-matched controls. We then explored the extent to which a range of commonly employed neuropsychological tasks in schizophrenia research are related to attentional impairment as measured in this way. Monotone counting performance was found to be correlated with digit span (WAIS-R-HK), information (WAIS-R-HK), comprehension (WAIS-R-HK), logical memory (immediate recall) (Weschler Memory Scale, WMS), and visual reproduction (WMS). Multiple regression analysis also identified visual reproduction, digit span and comprehension as significant predictors of attention performance. In contrast, logical memory (delay recall) (WMS), similarity (WAIS-R-HK), semantic fluency, and Wisconsin Card Sorting Test (perseverative errors) were not correlated with attention. In addition, no significant correlation between sustained attention and symptoms was found. These findings are discussed in the context of a weakly modular cognitive system where attentional impairment may contribute selectively to a range of other cognitive deficits.

Adolescent↗
PubMed1997

How are psychotic symptoms perceived? A comparison between patients, relatives and the general public.

OBJECTIVE: The aim of this study is to compare patients with schizophrenia with their relatives and the general public in their attitudes towards schizophrenic psychotic symptoms. METHOD: We used a case vignette depicting a person with typical schizophrenic psychotic symptoms and compared the attitudes of 44 inpatients and 47 outpatients with schizophrenia, 48 of their relatives and 43 members of the general public. We also compared the attitudes of patients with schizophrenia to their own symptoms and the symptoms described in the vignette. RESULTS: Subjects from the general public tended not to recognise psychotic symptoms as features of mental illness and tended not to consider drug treatment and hospitalisation as required. Sex, education level as well as previous contact with the mentally ill were found to be significant determinants of attitude. The levels of symptom awareness in patients with schizophrenia and their relatives are higher but still relatively low. In addition, we found that patients with schizophrenia who correctly appraised psychotic symptoms in another person were also aware of their own mental symptoms and need of treatment. CONCLUSIONS: The level of recognition of psychotic symptoms and awareness of a need for treatment are low in the general public, as well as in patients with schizophrenia and their relatives. These findings are discussed in relation to the assessment of insight in patients and a need for psychoeducational programs for each group.

Adolescent↗
PubMed1996

Blink rate, neurocognitive impairments, and symptoms in schizophrenia.

This study addresses the relationship between blink rate (as a measure of central dopaminergic activity), symptoms, neuropsychological performance, as well as neurological signs in schizophrenia. Blink rate between schizophrenic patients and a matched control group was compared in both "relaxed" and "attentive" conditions. Blink rate was increased in schizophrenic patients in the "relaxed" condition but not in the "attentive" condition. The relationship between blink rate and clinical variables was examined in a larger sample of 204 patients. In both "relaxed" and "attentive" conditions, blink rate was related to "hallucinations," "anxiety," negative symptoms, and neuroleptic dosage. Attention was a significant predictor only in the "relaxed" condition. No other significant correlation was found between blink rate, neuropsychological impairments, and neurological signs. These findings suggest that blink rate is not related to neurocognitive impairments in schizophrenia.

Adolescent↗
PubMed1996

Monitoring lead pollution near a storage battery recycling plant in Taiwan, Republic of China.

This study presents the distribution of blood lead levels and lead in various environmental samples (water, sediments, soils, and air) near the Shing-Yie storage battery recycling plant in Taiwan before (July 1990 to June 1991) and after (July 1992 to June 1993) amelioration. Before amelioration, the average blood lead levels in the neighborhood of the plant were in the range of 10.55 +/- 5.7 to 12.28 +/- 7.9 micrograms/dl. After amelioration, relatively lower average concentrations of blood lead (range 8.35 +/- 3.0 to 9.13 +/- 2.5 micrograms/dl) were generally found; however, these averages were still higher than that (7.79 +/- 3.5 micrograms/dl) from other lead-unpolluted areas of Taiwan. An exceedingly high geometric mean (GM) lead concentration (128 micrograms/L) was found in the downstream river water of the Tawulum River passing by the plant. The concentrations of lead (GM = 372 and 418 micrograms/g) in the downstream river sediments were higher than those (GM = 123 and 158 micrograms/g) in the upstream river sediments before and after amelioration, respectively. Furthermore, lead species in river sediments were analyzed by a sequential leaching technique. The sum of phases I, II, and III accounted for 83.7% of total lead at station R2 (nearest to the plant). Maximum lead concentration (GM = 2402 micrograms/g) in dust at the soil surface from station S1 (nearest to the plant) was much higher than those from the other stations by about 18 times before amelioration. However, the maximum value dropped to 1,155 micrograms/g after amelioration. On the whole, the geometric mean concentration of lead in dust at the soil surface nearest to the plant was > 1,000 micrograms/g and decreased to < 100 micrograms/g in the 15-30 cm depth soil about 2 km away from the plant. Before amelioration, the geometric mean lead concentration of 4.57 micrograms/m3 (range 0.102-37.6 micrograms/m3) in the air near the plant was higher than that at the background locations, the geometric mean value of which was 0.08 micrograms/m3.

Adolescent↗
PubMed1996

Neurological signs, age, and illness duration in schizophrenia.

Although increased prevalence of neurological signs in schizophrenia may reflect the presence of subtle brain dysfunctions, it is not clear whether there is progressive deterioration in such neurological function as the illness advances. This study compared neurological signs in patients with different durations of illness, controlling for age and education level. No deterioration in neurological signs as a function of illness duration was observed. Although there was an increase in neurological signs with age, there was a parallel increase in a control group. In addition, no change in the profile of subgroups of neurological signs was detected. These data provide further evidence for the stability of neurological dysfunction in schizophrenia. The findings are discussed in the context of the developmental origin of neurological dysfunction in schizophrenia.

Adolescent↗