Search PubMed⌕ Search

Biomedical subjects

C L Hsieh

Publications and source records attributed to C L Hsieh.

At least 55 records · Page 3Linked to original sources
PubMed1999

A cross-validation of the comprehensive assessment of activities of daily living after stroke.

This study aimed to determine whether the Frenchay Activities Index and the Barthel Index assess different factors in stroke patients who survive for more than one year. The Frenchay Activities Index and the Barthel Index were administered via telephone interview. One hundred and twenty-four patients from the community participated in the study. All items of the Barthel Index and the Frenchay Activities Index, except reading books, were included in a factor analysis to determine the underlying constructs of the items. Four factors were found. One factor comprised all items from the Barthel Index and one item from the Frenchay Activities Index. The rest of the Frenchay Activities Index items loaded on three other factors. The combined scores, using simple transformation, had satisfactory distributions. The results support the hypothesis that the Frenchay Activities Index and the Barthel Index assess different factors in stroke patients who survive for more than one year. The Barthel Index score and the Frenchay Activities Index score could be combined to assess the entire range of activities of daily living functions in stroke.

Activities of Daily Living↗
PubMed1999

Evidence that protein binding specifies sites of DNA demethylation.

It has been hypothesized that protein factors may protect CpG islands from methyltransferase during development and that demethylation may involve protein-DNA interactions at demethylated sites. However, direct evidence has been lacking. In this study, demethylation at the EBNA-1 binding sites of the Epstein-Barr virus latent replication origin, oriP, was investigated by using human cells. Several novel findings are discussed. First, there are specific preferential demethylation sites within the oriP region. Second, the DNA sequence of oriP alone is not the target of an active demethylation process. Third, EBNA-1 binding is required for the site-specific demethylation in oriP. Interestingly, CpG sites adjacent to and between the EBNA-1 sites do not become demethylated. Fourth, demethylation of the first DNA strand in oriP at the EBNA-1 binding sites involves a passive (replication-dependent) mechanism. The second-strand demethylation appears to occur through an active mechanism. That is, EBNA-1 protein binding prevents the EBNA-1 binding sites from being remethylated after one round of DNA replication, and it appears that an active demethylase then demethylates these hemimethylated sites. This study provides clear evidence that protein binding specifies sites of DNA demethylation and provides insights into the sequence of steps and the mechanism of demethylation.

Base Sequence↗
PubMed1999

In vivo activity of murine de novo methyltransferases, Dnmt3a and Dnmt3b.

The putative de novo methyltransferases, Dnmt3a and Dnmt3b, were reported to have weak methyltransferase activity in methylating the 3' long terminal repeat of Moloney murine leukemia virus in vitro. The activity of these enzymes was evaluated in vivo, using a stable episomal system that employs plasmids as targets for DNA methylation in human cells. De novo methylation of a subset of the CpG sites on the stable episomes is detected in human cells overexpressing the murine Dnmt3a or Dnmt3b1 protein. This de novo methylation activity is abolished when the cysteine in the P-C motif, which is the catalytic site of cytosine methyltransferases, is replaced by a serine. The pattern of methylation on the episome is nonrandom, and different regions of the episome are methylated to different extents. Furthermore, Dnmt3a also methylates the sequence methylated by Dnmt3a on the stable episome in the corresponding chromosomal target. Overexpression of human DNMT1 or murine Dnmt3b does not lead to the same pattern or degree of de novo methylation on the episome as overexpression of murine Dnmt3a. This finding suggests that these three enzymes may have different targets or requirements, despite the fact that weak de novo methyltransferase activity has been demonstrated in vitro for all three enzymes. It is also noteworthy that both Dnmt3a and Dnmt3b proteins coat the metaphase chromosomes while displaying a more uniform pattern in the nucleus. This is the first evidence that Dnmt3a and Dnmt3b have de novo methyltransferase function in vivo and the first indication that the Dnmt3a and Dnmt3b proteins may have preferred target sites.

Animals↗
PubMed1999

Changes of pulse rate and skin temperature evoked by electroacupuncture stimulation with different frequency on both Zusanli acupoints in humans.

The purpose of this study was to investigate the effect of electroacupuncture stimulation (EA) of different frequency on pulse rate and skin temperature. Sixteen healthy male medical student volunteers received EA of 2 Hz, and 100 Hz, respectively on the both Zusanli acupoints (St-36) while resting. Their pulse rates were measured on the middle finger, and skin temperature was taken between the thumb and index finger before, during, and after EA stimulation. Each test took 35 minutes. The initial 10 min were defined as baseline period (no EA), the following 15 min as the EA period and the last 10 min as the post-EA period. Three assessments were performed on each subject as follows: A) control assessment: no EA was done throughout the test; B) 2 Hz EA assessment: 2 Hz EA was applied to both Zusanli acupoints during the EA period; and C) 100 Hz EA assessment: 100 Hz EA was applied to both Zusanli acupoints during the EA period. Our results indicate that both 2 Hz EA and 100 Hz EA decreased pulse rates during the EA period, and these changes remained throughout the post-EA period in 2 Hz EA assessment, but not in 100 Hz EA assessment. Both 2 Hz and 100 Hz EA resulted in decreases of skin temperature during the EA period. Our conclusions are that 2 Hz EA and 100 Hz EA applied to both Zusanli acupoints resulted in the decrease of pulse rate, which possibly evoked greater parasympathetic nerve activity on heart beats. 2 Hz EA had a more sustained effect on heart beats than 100 Hz EA. Decreased skin temperatures in the EA period may have resulted from cutaneous vasoconstriction caused by EA induced sympathetic stress response, suggesting EA at least remains for 15 min in clinical application.

Acupuncture Points↗
PubMed1999

Anticonvulsant effect of Uncaria rhynchophylla (Miq) Jack. in rats with kainic acid-induced epileptic seizure.

This study investigated the anticonvulsant effect of Uncaria rhynchophylla (UR) and the physiological mechanisms of its action in rats. A total of 70 male Sprague-Dawley (SD) rats were selected for study. Thirty four of these rats were divided into 5 groups as follows: 1) CONTROL GROUP (n = 6): received intraperitoneal injection (i.p.) of kainic acid (KA, 12 mg/kg); 2) UR1000 group (n = 10), 3) UR500 group (n = 6) 4) UR250 group, received UR 1000, 500, 250 mg/kg i.p. 30 min prior to KA administration, respectively; 5) Contrast group: received carbamazepine 20 mg/kg i.p. 30 min prior to KA administration. Behavior and EEG were monitored from 15 min prior to drug administration to 3 hours after KA administration. The number of wet dog shakes were counted at 10 min intervals throughout the experimental course. The remaining 36 rats were used to measure the lipid peroxide level in the cerebral cortex one hour after KA administration. These rats were divided into 6 groups of 6 rats as follows: 1) Normal group: no treatment was given; 2) CONTROL GROUP: received KA (12 mg/kg) i.p.; 3) UR1000 group, 4) UR500 group, 5) UR250 group, received UR 1000, 500, 250 mg/kg i.p. 30 min prior to KA administration, respectively; 6) Contrast group: received carbamazepine 20 mg/kg i.p. 30 min prior to KA administration. Our results indicated that both UR 1000 and 500 mg/kg decreased the incidence of KA-induced wet dog shakes, no similar effect was observed in the UR 250 mg/kg and carbamazepine 20 mg/kg group. Treatment with UR 1000 mg/kg, 500 mg/kg, or 250 mg/kg and carbamazepine 20 mg/kg decreased KA-induced lipid peroxide level in the cerebral cortex and was dose-dependent. These findings suggest that the anticonvulsant effect of UR possibly results from its suppressive effect on lipid peroxidation in the brain.

Animals↗
PubMed1998

Involvement of the 5' proximal coding sequences of hepatitis C virus with internal initiation of viral translation.

The 5' nontranslated region (NTR) of hepatitis C virus (HCV) consists of 341 nucleotides (nt). This region comprises the majority of the internal ribosome entry site (IRES) which controls the efficiency of viral translation. Previous studies of the 3' boundary of the HCV IRES yielded conflicting data regarding the involvement of viral coding sequences in IRES activity. We therefore studied the functional significance of the 5' proximal coding sequences of the HCV core gene on IRES activity. We constructed monocistronic and bicistronic DNAs that contained either a chloramphenicol acetyl transferase (CAT) gene or a luciferase (Luc) gene as the reporter. Results from both in vitro and in vivo experiments indicated that the optimal IRES ranged within nt 1-371. Further mutational analyses of sequences surrounding the initiation codon revealed that primary sequences downstream of the AUG initiator rather than the secondary structure are important in regulating optimal IRES function. We are also able to demonstrate that a non-AUG codon could be used to initiate the synthesis of a reporter protein, albeit with lower efficiency. These findings bear important implications for the HCV IRES secondary structures.

5' Untranslated Regions↗
PubMed1998

Stochastic, stage-specific mechanisms account for the variegation of a human globin transgene.

The random insertion of transgenes into the genomic DNA of mice usually leads to widely variable levels of expression in individual founder lines. To study the mechanisms that cause variegation, we designed a transgene that we expected to variegate, which consisted of a beta-globin locus control region 5' HS-2 linked in tandem to a tagged human beta-globin gene (into which a Lac-Z cassette had been inserted). All tested founder lines exhibited red blood cell-specific expression, but levels of expression varied >1000-fold from the lowest to the highest expressing line. Most of the variation in levels of expression appeared to reflect differences in the percentage of cells in the peripheral blood that expressed the transgene, which ranged from 0.3% in the lowest expressing line to 88% in the highest; the level of transgene expression per cell varied no more than 10-fold from the lowest to the highest expressing line. These differences in expression levels could not be explained by the location of transgene integration, by an effect of beta-galactosidase on red blood cell survival, by the half life of the beta-galactosidase enzyme or by the age of the animals. The progeny of all early erythroid progenitors (BFU-E colony-forming cells) exhibited the same propensity to variegate in methylcellulose-based cultures, suggesting that the decision to variegate occurs after the BFU-E stage of erythroid differentiation. Collectively, these data suggest that variegation in levels of transgene expression are due to local, integration site-dependent phenomena that alter the probability that a transgene will be expressed in an appropriate cell; however, these local effects have a minimal impact on the transgene's activity in the cells that initiate transcription.

Age Factors↗
PubMed1998

V(D)J recombination activity in human hematopoietic cells: correlation with developmental stage and genome stability.

V(D)J recombinase activity was measured in an array of human cell lines derived from hematopoietic malignancies representing various lineages and developmental stages. The level of recombinase activity was found to vary over a 2000-fold range between different cell lines. Several myeloid cell lines were positive for V(D)J recombinase activity, providing additional insight into the relationship between myeloid and lymphoid differentiation. Despite high levels of V(D)J recombination in two human acute lymphoblastic leukemia cell lines, the cytogenetic karyotype has remained essentially constant over several years of continuous cell culture. Silencing of recombination of chromosomal and minichromosomal targets has been strongly correlated with the replication of CpG methylated DNA in murine cells. Here, in human cells, we show that human minichromosomes bearing V(D)J recombination signals are protected well over 100-fold from recombination if they are CpG methylated, providing a rational basis for the karyotypic stability in cells with high levels of V(D)J recombination activity.

Animals↗
PubMed1998

Inter-rater reliability and validity of the action research arm test in stroke patients.

BACKGROUND AND PURPOSE: The Action Research arm test (ARAT) was constructed for assessing recovery of upper extremity function after cortical injury. The objective of the study was to verify the inter-rater reliability and validity of the ARAT in stroke patients. METHODS: 50 stroke patients participated in the study. For the purpose of inter-rater study, the ARAT was administered by three experienced raters on each patient within a 3-day period. Validity was assessed by comparing the patients' scores on the ARAT with those obtained for the other well-validated measurements evaluating upper extremity motor impairment and disability. RESULTS: Intra-class correlation coefficient (ICC) for the total score was 0.98 indicating very high inter-rater reliability. ICCs were also very high in each of the subscales. The score of the ARAT was closely correlated with that of the upper extremity part of the motor assessment scale, the arm sub-score of the motricity index and the upper extremity movements of the modified motor assessment chart (Pearson r = 0.96, 0.87 and 0.94, respectively). CONCLUSION: The preliminary results of this study support the value of the ARAT for measuring recovery of arm-hand function in stroke patients.

Aged↗
PubMed1998

Modulation of cerebral cortex in acupuncture stimulation: a study using sympathetic skin response and somatosensory evoked potentials.

Although acupuncture has been widely used for treating disorders, its therapeutic mechanism remains unclear. In order to study the physiological mechanism of acupuncture stimulation, both palm recordings of sympathetic skin response (SSR) were evoked by electrical stimulation of the right median nerve on 13 normal adult volunteers. Median nerve evoked short-latency somatosensory evoked potential (SEPs) recordings were taken at least one week after SSR recording. The latencies and amplitudes were calculated. N13 component was obtained from Cv7, and N20 and P25 were from somatosensory cortex. The control did not receive acupuncture stimulation. Acupuncture needles were inserted into both Zusanli (St-36) acupoints as follows: 1) manual acupuncture (MA): using fingers to twist the acupuncture needle until so-called Der-Qi was obtained, 2) 2 Hz electroacupuncture (EA): 2 Hz square-wave electrical pulses were applied between the Zusanli needle and the Shangjuxu (St-37) needle bilaterally. Our results indicated that the mean latencies of SSR were largest during 2 Hz EA followed by MA stimulation, whereas the period of control exhibited the shortest mean latencies. In contrast, the mean amplitudes of SSR were smallest during the period of 2Hz EA, followed by the period of MA, and the period of control exhibited the largest mean amplitudes of SSR. The latencies of N13, N20 and P25 remained unchanged, but the amplitudes of P25 were largest during the period of 2Hz EA, followed by the period of MA; the period of control exhibited the smallest mean amplitudes of SEPs. The results suggest that acupuncture stimulation of both Zusanli acupoints inhibited SSR, which implies that the cerebral cortex contributed at least in part to this inhibition. The stimulation effect of 2Hz EA is stronger than MA.

Acupuncture Points↗
PubMed1998

Cerebral cortex participation in the physiological mechanisms of acupuncture stimulation: a study by auditory endogenous potentials (P300).

Although acupuncture has traditionally used the acupoints formula to treat diseases, the physiological mechanisms involved and the effectiveness of therapy remain unclear. This study investigated the physiological mechanism(s) and response to acupuncture stimulation using the acupoints formula. Scalp-recorded potentials P300 were evoked by auditory stimulation of non-target and target in 13 normal adult volunteers. Latencies and amplitudes were measured. Three assessments were performed in each subject over a period of at least one week. Each assessment was divided into a control period with no acupuncture stimulation, followed by an acupuncture period and then a post-acupuncture period. Acupuncture needles were inserted into the body as follows: 1) non-acupoint: acupuncture needles were inserted 2 cm lateral to both Zusanli acupoints; 2) acupoint: acupuncture needles were inserted into both Zusanli acupoints; 3) acupoints formula: acupuncture needles were inserted into both Zusanli and Shousanli acupoints. Our results showed that both acupoint and acupoints formula assessments resulted in a significant decrease of P300 amplitudes during the acupuncture and post-acupuncture periods. However, there was significant difference in P300 amplitudes in the non-acupoint assessment during these periods. P300 changes in latencies and amplitudes were not significantly different between the acupoint assessment and the acupoints formula assessment. We concluded that acupuncture stimulation of both Zusanli acupoints resulted in a decrease of P300 amplitudes, suggesting the involvement of the cerebral cortex in sensory interaction when simultaneous sensations of the two types are received. No similar changes were observed in the non-acupoint assessment, which have been suggested to be related to so-called acupoint specificity. Results obtained using the acupoints formula were not significantly different from those using acupoints alone. These findings suggested that neuropsychological effects from stimulation of Zusanli acupoints and Shousanli acupoints are different.

Acoustic Stimulation↗
PubMed1997

Regression of established mouse leukemia by GM-CSF-transduced tumor vaccine: implications for cytotoxic T lymphocyte responses and tumor burdens.

This study investigated the therapeutic effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) on a mouse leukemia model. By using a retroviral vector, mouse GM-CSF cDNA was transduced into a highly tumorigenic T leukemia cell line, RL male 1. Injection of GM-CSF-secreting RL male 1 cells into syngeneic BALB/c mice elicited protective immunity in the animals, which could regress preestablished tumors introduced either by a subcutaneous or in an intravenous route. However, the therapeutic effects were less prominent in the mice inoculated with a large tumor load or in mice treated later. Winn tests further demonstrated that the splenocytes from the late-treated group conferred poorer protective effects in terms of reducing the growth of parental RL male 1 cells in naive mice than the splenocytes from the early-treated group. Nonetheless, upon stimulation in vitro, the activity of tumor-specific cytotoxic T lymphocytes (CTL) was comparable in the splenocytes of both groups of mice. Histological analysis also indicated that the CD8+ T cells appeared as early as 3 days following vaccination at the vaccine sites and at the tumor sites in both groups of mice. Above observations implied that the T cells in the animals bearing large tumors appeared to be in a state of suppression or anergy. Systematic histological analyses for 2 weeks provided further insight into various infiltrates at the vaccine sites and at the tumor sites in response to the inoculation of GM-CSF-secreting tumor vaccine.

Animals↗
PubMed1997

Stability of patch methylation and its impact in regions of transcriptional initiation and elongation.

CpG DNA methylation has previously been correlated with the suppression of transcription. The mechanism of this suppression is not understood, and many aspects of the temporal and positional relationships between the region of methylation and transcription have not yet been defined. Here, 12-kb stable replicating episomes that can be maintained in human somatic cells for weeks to months were used. Such a system allows more direct manipulation and is free from the positional effects attendant with the analysis of endogenous loci or integrated transgenes. By using these circular minichromosomes, patches of CpG methylation were created to include or exclude the regions of transcriptional initiation and elongation. I found that a 0.5-kb patch of methylation that covered the promoter suppressed expression only 2-fold and that a 1.9-kb patch of methylation that covered the coding portion of the gene (but not the promoter) suppressed expression about 10-fold. In contrast, methylation of the entire minichromosome except for the promoter or the coding portion suppressed transcription about 50- to 200-fold. I infer the following. Methylation of the 0.5-kb promoter fragment does not significantly affect transcription at the level of transcription factor binding or local chromatin structure. The dominant effect on transcription occurs when the length of methylated DNA is long, with little disproportionate effect of methylation of specific regions, such as that of initiation or elongation. I also found that the boundaries between these methylated and unmethylated regions remained stable for the many weeks that I monitored them.

Cell Line↗
PubMed1997

Antioxidant effects of dopamine and related compounds.

The antioxidant and free radical scavenging effects of dopamine, noradrenaline, tyramine, and tyrosine were investigated and compared with alpha-tocopherol. The antioxidant effect of dopamine and its related compounds on peroxidation of linoleic acid were in the order of dopamine > alpha-tocopherol = tyramine > tyrosine > noradrenaline as measured by the thiocyanate method. These amine compounds had reducing power, and a scavenging effect on reactive oxygen species, i.e., superoxide anion and hydroxyl radical. The results for reducing power and scavenging effect of these amine compounds had a similar trend as their inhibition of linoleic acid peroxidation. The antioxidant activity of these amine compounds in soybean oil was also evaluated by the Rancimat method. The induction time to reach 100 meq/kg peroxide value (POV) of soybean oil for dopamine, alpha-tocopherol, tyramine, tyrosine, noradrenaline, and control were 9.0, 8.2, 8.0, 6.4, 4.6, and 4.3 h, respectively. The antioxidant efficacy of amine compounds seems to be correlated with the numbers of hydroxy groups and their position on the phenolic ring.

Antioxidants↗
PubMed1997

Vitrectomy for endogenous Klebsiella pneumoniae endophthalmitis with massive subretinal abscess.

A 39-year-old man with pyogenic liver abscess had bilateral endogenous Klebsiella pneumoniae endophthalmitis. At presentation, the left eye had a localized subretinal abscess. Despite repeated intravitreal amikacin and dexamethasone injections, a subretinal abscess spread and detached all of the retina. Pars plana vitrectomy with drainage of the subretinal abscess was performed. The retina was reattached, and the patient had 5/200 vision 5 months postoperatively. Early vitrectomy with drainage of the subretinal abscess may save some eyes with endogenous Klebsiella pneumoniae endophthalmitis.

Abscess↗
PubMed1997

Factors influencing vocational outcomes following stroke in Taiwan: a medical centre-based study.

This study was aimed at identifying the factors relating to return to work for stroke patients of working age in Taiwan, adjusting for confounding factors. A retrospective cohort study was used to test the association between patients' characteristics, such as medical condition at admission and sociodemographic factors, and the degree of return to work after stroke. Two hundred and forty-eight consecutive stroke survivors discharged from the National Taiwan University Hospital participated in the follow-up survey. Variables considered likely to influence return to work were collected from the patients' hospital records. Vocational outcomes were collected via questionnaire. Return to work was classified into four levels: (I) no return to work; (II) limited return to work; (III) partial return to work; and (IV) complete return to work. Of the 248 subjects surveyed, 105 (42.7%) subjects had not returned to work, 32 (12.9%) subjects had returned to work on a limited basis, 43 (17.3%) subjects had partially returned, and 68 (27.4%) subjects had returned to work completely. Cramer's V test and stepwise logistic regression were employed to examine factors influencing return to employment. Maximum weakness and employment institution were identified as the strongest predictors of return to work. In brief, nearly three-quarters of the patients did not resume their usual work roles after stroke. Maximum weakness and employment institution were the strongest predictors of return to work following a stroke in Taiwan.

Cerebrovascular Disorders↗