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Biomedical subjects

E Chen

Publications and source records attributed to E Chen.

At least 55 records · Page 3Linked to original sources
PubMed2000

Behavioral and cognitive interventions in the treatment of pain in children.

A wide range of behavioral and cognitive techniques have been found to be efficacious for helping children to cope with acute pain. Research into the clinical applicability of these interventions is at an early stage but increasingly is being recognized as an important future direction. Many existing interventions and assessment tools are reasonably easy to use, allowing practitioners to have the tools to identify children most vulnerable to pain and to significantly reduce pain-related distress in these children. For additional information from the Internet, please visit the UCLA Pediatric Pain Program Web site: http:¿members.xoom.com/UCLAPAIN/.

Acute Disease↗
PubMed2000

Inhibition of phosphatidylinositol 3-kinase and protein kinase C attenuates extracellular matrix protein-induced vascular smooth muscle cell chemotaxis.

PURPOSE: Intimal hyperplasia (IH), a significant cause of vascular reconstructive failure, is characterized by abnormal vascular smooth muscle cell (VSMC) migration, proliferation, and extracellular matrix (ECM) deposition. The ECM proteins, thrombospondin-1 (TSP-1), fibronectin (Fn), and vitronectin (Vn) can induce VSMC migration; however, the cellular signaling pathways involved are not identical for each ECM protein. Phosphatidylinositol 3-kinase (PI3K) and protein kinase C (PKC) are two enzymes that have been associated with VSMC migration. We sought to elucidate the roles of these enzymes in TSP-1-, Fn-, and Vn-stimulated VSMC migration. METHODS: Chemotaxis assays were performed by using a modified Boyden Chamber. TSP-1, Fn, or Vn (20 microg/mL) or serum-free media (SFM) was placed in the bottom wells of the chamber. Quiescent bovine aortic VSMC were preincubated with LY 294002 (100 micromol/L), a PI3K inhibitor, bisindolylmaleimide I (GF 109203X, 1 micromol/L), a PKC inhibitor, or in SFM alone for 30 minutes. VSMCs (50,000 cells per well) were then placed in the top wells of the chamber, and the assay was conducted for 4 hours at 37 degrees C. Results were recorded as the number of cells migrated per five fields (400x) and analyzed by means of the paired t test, with P value less than.05 considered to be significant (n = 3). RESULTS: The VSMC migration was significantly increased by TSP-1, Fn, and Vn. LY 294002 inhibited TSP-1-, Fn-, and Vn-stimulated VSMC migration (85% to 89%, P <.05). GF 109203X inhibited only TSP-1-stimulated migration (65%, P <.05). CONCLUSION: These results suggest that TSP-1-, Fn-, and Vn-stimulated migration is at least partially dependent on PI3K. However, only TSP-1 stimulated migration is at least partially dependent on PKC.

Animals↗
PubMed2000

Pain-sensitive temperament: does it predict procedural distress and response to psychological treatment among children with cancer?

OBJECTIVE: To evaluate the relationship between pain sensitivity and children's distress during lumbar punctures (LPs), and whether pain sensitivity functions as a moderator of children's responses to a psychological intervention aimed at reducing LP distress. METHOD: Fifty-five children with acute lymphoblastic leukemia (ages 3 to 18) and their parents completed a questionnaire measure of pain sensitivity. Self-report, physiological, and observed measures of distress were collected during the study baseline LP. Children were then randomized into a psychological intervention or an attention control group. Postintervention and follow-up LPs were observed. RESULTS: Higher levels of pain sensitivity were associated with greater anxiety and pain, both prior to and during the LP. Preliminary analyses indicated that pain sensitivity moderated the effects of intervention on distress. Children who were more pain-sensitive and who received no intervention showed greater increases in LP distress over time. In contrast, children who were more pain-sensitive and who received intervention showed greater decreases in LP distress over time. CONCLUSIONS: A measurement of pain sensitivity may be useful in pediatric oncology settings for effectively targeting pain-vulnerable children for psychological intervention. Preliminary analyses indicate that an empirically-supported intervention for procedural distress is efficacious for those children who are most pain-sensitive.

Adaptation, Psychological↗
PubMed2000

Eleven densely clustered genes, six of them novel, in 176 kb of mouse t-complex DNA.

Targeted sequencing of the mouse t-complex has started with a 176-kb, gene-rich BAC localized with six PCR-based markers in inversion 2/3 of the highly duplicated region. The sequence contains 11 genes recovered primarily as cDNAs from early embryonic collections, including Igfals (previously placed on chromosome 17), Nubp2 (a fully characterized gene), Jsap1 (a JNK-binding protein), Rsp29 (the mouse homologue of the rat gene), Ndk3 (a nucleoside diphosphate kinase), and six additional putative genes of unknown function. With 50% GC content, 75% of the DNA transcribed, and one gene/16.0 kb (on average), the region may qualify as one of the most gene-dense segments in the mouse genome and provides candidates for dosage-sensitive phenotypes and mouse embryonic lethals mapped to the vicinity.

Animals↗
PubMed2000

Primary closure of mammalian bites.

OBJECTIVE: Suturing of bite wounds remains controversial. The authors evaluated the incidence of wound infection in 145 mammalian bite wounds treated with primary closure. METHODS: Consecutive patients with bite wounds receiving primary closure at a university hospital ED had structured closed-question data sheets completed at the time of wound management and suture removal. Infection was determined at the time of suture removal using a previously validated definition. Data included demographics; medical history; time from injury to evaluation; wound characteristics and location; details of wound cleansing methods, debridement, foreign body removal, and wound closure methods; use of antibiotics; and follow-up wound evaluation. Proportions and 95% confidence intervals were calculated. RESULTS: One hundred forty-five mammalian bite patients were enrolled: 88 dog, 45 cat, and 12 human bites. Patients had a mean (+/-SD) age of 21 +/- 20 years; 58% were male; 86% were white; and they presented a mean (+/-SD) of 1.8 +/- 1.2 hours after injury. Bites occurred on the head and neck (57%), upper extremity (36%), and lower extremity (6%). Wounds had a mean length and width of 2.5 cm and 4.8 mm, respectively. Twelve percent involved structures deep to subcutaneous tissue. After primary wound closure, wound infections occurred in eight patients (5.5%; 95% confidence interval = 1.8% to 9.2%). CONCLUSIONS: The data suggest that carefully selected mammalian bite wounds can be sutured with approximately a 6% rate of infection. This infection rate may be acceptable in lacerations where cosmesis is a primary concern.

Adult↗
PubMed2000

3 year simvastatin treatment and lens nuclear back scattering.

AIM: To determine if 3 year treatment of hypercholesterolaemia with simvastatin causes an increase of lens nuclear back scattering. METHODS: 160 patients with hypercholesterolaemia in the Scandinavian Simvastatin Survival Study (4S) were followed for 3 years. Half (80) of the patients took simvastatin and half (80) received placebo. The lens was photographed with a Topcon SL-45 slit lamp camera at the beginning and at 1 year intervals. A common lens nuclear area was used for measuring lens nuclear back scattering. RESULTS: Nuclear back scattering increased with age and there was more pronounced scattering in women than in men. Lens nuclear back scattering did not differ significantly between the simvastatin and placebo groups, but the power was low (0.2). Lens nuclear back scattering increased during the study period independently of baseline back scattering, age, and sex for both groups. CONCLUSION: Although no significant difference was found between the simvastatin and placebo groups, the currently available data are insufficient for exclusion of the possibility that taking simvastatin during a 3 year period increases nuclear back scattering. However, a possible minor increase of nuclear back scattering is clinically irrelevant considering known beneficial effects of simvastatin on coronary heart disease.

Adult↗
PubMed2000

A study of communication in the Cardiac Surgery Intensive Care Unit and its implications for automated briefing.

We present a study of the information transferred among caregivers in the context of cardiac surgery and use the study to evaluate a system, MAGIC, that we are developing for automated generation of briefings. Our framework integrates cognitive and quantitative evaluation methods and features three standards that reflect current practice in the Cardiothoracic Intensive Care Unit (CTICU). Using experimental design to compare human-generated and machine-generated briefings, we show that MAGIC's current level of performance is useful. Moreover, MAGIC could help improve information flow in the CTICU by providing a consistent set of information earlier than in current practice. The separate standards are also consistent in suggesting specific modifications that may be necessary for iterative design and further system development.

Communication↗
PubMed2000

[The design of axial flow pump].

Axial flow pump has been the hot point of the research field of circulatory support. This article has outlined the basic principle of its design and the methodology of its experimental study, and explained that excellent engineer design, avoiding turbulence, cavitation and wake, and reducing the destroy of red blood cells were the goal to get in design process. The computer-supported design and virtual experiment offered the high efficient tool for the above design. The axial pump has a broad scope in future clinical application.

Computer-Aided Design↗
PubMed2000

[Selective inhibition of HSV-1 DNA and protein synthesis by antiviral antibiotic 17997].

OBJECTIVE: To study the effects of 17997 on the HSV-1 DNA and protein synthesis. METHODS: DNA synthesis was determined by isopycnic separation of cellular and viral DNA in CsCl gradients centrifugation. Protein synthesis was determined by SDS-PAGE and Western blot. RESULTS: The inhibition rates of 0.5 micromol/L, 1.0 micromol/L, 2.0 micromol/L and 4.0 micromol/L of 17997 on HSV-1 DNA synthesis were 63.1%,74. 1%, 93.9% and 100%, respectively. 4.0 micromol/L of 17997 did not inhibit VERO cell DNA synthesis. The above concentrations of 17997 did not show any inhibitory effects on cellular protein synthesis, but selectively inhibited on viral protein synthesis. CONCLUSIONS: 17997 selectively displayed inhibitive effects on HSV-1 DNA and protein synthesis.

Animals↗
PubMed2000

[Zero-stress state of renal artery in spontaneously hypertensive rats].

By observing the opening angle of the renal artery, the zero-stress state of the renal artery was studied in spontaneously hypertensive rats (SHR) prior to and posterior to their hypertension, and the role of endogenous angiotensin II (Ang II) and endothelin (ET) on the zero-stress state was studied by giving SHR Losartan(AT1 receptor antagonist of Ang II) and BMS-182874 (an A type receptor antagonist of ET) respectively. The opening angle of the renal artery in SHR with established hypertension was much greater than that in wistar-Kyoto rats(WKY) (114.2 +/- 42.2 vs 70.2 +/- 30.4, P < 0.01). The opening angles of the renal artery in SHR treated with Losartan and BMS-182874 were much smaller than those in control SHR. The opening angles of the renal artery in Losartan-treated and BMS-182874-treated SHR were 65.9 +/- 32.7 and 66.6 +/- 41.54 respectively. The results suggest that non-unequal growth exists in the renal arterial wall in SHR with established hypertension and the residual stress and strain in SHR are greater than those in age-matched WKY. Endogenous Ang II and ET may play a role in the changes of zero-stress state in SHR with hypertension.

Angiotensin II↗
PubMed1999

STEAP: a prostate-specific cell-surface antigen highly expressed in human prostate tumors.

In search of novel genes expressed in metastatic prostate cancer, we subtracted cDNA isolated from benign prostatic hypertrophic tissue from cDNA isolated from a prostate cancer xenograft model that mimics advanced disease. One novel gene that is highly expressed in advanced prostate cancer encodes a 339-amino acid protein with six potential membrane-spanning regions flanked by hydrophilic amino- and carboxyl-terminal domains. This structure suggests a potential function as a channel or transporter protein. This gene, named STEAP for six-transmembrane epithelial antigen of the prostate, is expressed predominantly in human prostate tissue and is up-regulated in multiple cancer cell lines, including prostate, bladder, colon, ovarian, and Ewing sarcoma. Immunohistochemical analysis of clinical specimens demonstrates significant STEAP expression at the cell-cell junctions of the secretory epithelium of prostate and prostate cancer cells. Little to no staining was detected at the plasma membranes of normal, nonprostate human tissues, except for bladder tissue, which expressed low levels of STEAP at the cell membrane. Protein analysis located STEAP at the cell surface of prostate-cancer cell lines. Our results support STEAP as a cell-surface tumor-antigen target for prostate cancer therapy and diagnostic imaging.

Amino Acid Sequence↗
PubMed1999

Estrogen receptor immunoreactivity within subregions of the rat forebrain: neuronal distribution and association with perikarya containing choline acetyltransferase.

Administration of the neuroactive steroid hormone estrogen has been shown to effect cholinergic basal forebrain neuronal function. Antibodies directed against the estrogen receptor alpha (ERalpha) revealed dark (type 1) and light (type 2) nuclear positive neurons within the islands of Calleja, endopiriform nucleus, lateral septum, subfields of the cholinergic basal forebrain, bed nucleus of the stria terminalis, striohypothalamic region, medial preoptic region, periventricular, ventromedial, arcuate and tuberal mammillary nuclei of the hypothalamus, reuniens and anterior medial thalamic nuclei, amygdaloid complex, piriform cortex and subfornical organ. In contrast, only a few scattered ERalpha labeled neurons were found in cortex and hippocampus. ERalpha stained cell bodies were not seen in the striatum. Counts of ERalpha labeled neurons in intact female rats revealed significantly more type 2 neurons within the basal forebrain subfields. Quantitation of ERalpha immunoreactive neurons revealed a significant decrease in the relative number of type 1 neurons within the medial septum (MS), horizontal limb of the diagonal band (HDB) and substantia innominata/nucleus basalis (SI/NB) following ovariectomy. Quantitation following choline acetyltransferease (ChAT) immunohistochemistry revealed a significant decrease in the number of ChAT positive neurons within the MS, HDB and SI/NB, but not VDB following ovariectomy. Following ovx, the percentage of double labeled cholinergic basal forebrain neurons also declined significantly within the MS, VDB, HDB and SI/NB. These observations suggest that estrogen effects a subpopulation of cholinergic basal forebrain neurons and may provide insight into the biologic actions of this steroid in Alzheimer's disease.

Animals↗
PubMed1999

Genomic sequence, structural organization, molecular evolution, and aberrant rearrangement of promyelocytic leukemia zinc finger gene.

The promyelocytic leukemia zinc finger gene (PLZF) is involved in chromosomal translocation t(11;17) associated with acute promyelocytic leukemia. In this work, a 201-kilobase genomic DNA region containing the entire PLZF gene was sequenced. Repeated elements account for 19.83%, and no obvious coding information other than PLZF is present over this region. PLZF contains six exons and five introns, and the exon organization corresponds well with protein domains. There are at least four alternative splicings (AS-I, -II, -III, and -IV) within exon 1. AS-I could be detected in most tissues tested whereas AS-II, -III, and -IV were present in the stomach, testis, and heart, respectively. Although splicing donor and acceptor signals at exon-intron boundaries for AS-I and exons 1-6 were classical (gt-ag), AS-II, -III, and -IV had atypical splicing sites. These alternative splicings, nevertheless, maintained the ORF and may encode isoforms with absence of important functional domains. In mRNA species without AS-I, there is a relatively long 5' UTR of 6.0 kilobases. A TATA box and several transcription factor binding sites were found in the putative promoter region upstream of the transcription start site. PLZF is a well conserved gene from Caenorhabditis elegans to human. PLZF paralogous sequences are found in human genome. The presence of two MLL/PLZF-like alignments on human chromosome 11q23 and 19 suggests a syntenic replication during evolution. The chromosomal breakpoints and joining sites in the index acute promyelocytic leukemia case with t(11;17) also were characterized, which suggests the involvement of DNA damage-repair mechanism.

Alternative Splicing↗
PubMed1999

Concentration-dependent effects of muscimol to enhance pulsatile GnRH release from GT1-7 neurons in vitro.

Immortalized GT1-7 neurons were used to characterize the effect of muscimol, a GABAA receptor agonist, to enhance pulsatile gonadotropin-releasing hormone (GnRH) release. GT1-7 neurons were grown on Cytodex-3 beads and placed in special superfusion microchambers. The cells were superfused at a rate of 6.2 ml x h-1 with Media 199 (pH 7.35) using a commercially available perfusion system. After a pre-muscimol period of 120 min, the cells were exposed for 5 min to 0.35, 1, 5 or 10 microM muscimol or 5 microM muscimol+20 microM of the GABAA receptor antagonist, bicuculline. Following removal of the muscimol (and bicuculline, in the case of the latter experiment), the superfusion was continued for another 115 min. Sample fractions were collected at 5 min intervals throughout the perfusion. Basal GnRH release from the GT1-7 neurons was pulsatile with an average interpulse interval of 45.4+/-0.5 min and an average pulse amplitude of 191.5+/-22.6 pg x min x ml-1. Our results also demonstrated that the GABAA receptor agonist, muscimol, enhances pulsatile GnRH release from GT1-7 neurons in culture. The response to muscimol was saturable and concentration-dependent with an EC50 of 0.47 microM. The effects of 5 microM muscimol to increase GnRH pulsatility were blocked by co-exposure to the GABAA receptor antagonist, bicuculline. The average GnRH interpulse intervals were 41.7+/-1.8 min, 32.5+/-2.9 min, 30.6+/-0.7 min and 25.5+/-0.4 min in the period following exposure to 0.35, 1, 5 and 10 microM of muscimol, respectively (post-muscimol period). GnRH pulse amplitude (mean-area for each pulse) was increased during exposure to muscimol but not during the pre- or post-muscimol periods. The GABAA receptor antagonist, bicuculline, itself had no effect on pulsatile GnRH release. These results are consistent with previously published reports suggesting that activation of the GABAA receptor stimulates hypothalamic GnRH release in embryonic and neonatal animals.

Animals↗
PubMed1999

Multiple pathways on a protein-folding energy landscape: kinetic evidence.

The funnel landscape model predicts that protein folding proceeds through multiple kinetic pathways. Experimental evidence is presented for more than one such pathway in the folding dynamics of a globular protein, cytochrome c. After photodissociation of CO from the partially denatured ferrous protein, fast time-resolved CD spectroscopy shows a submillisecond folding process that is complete in approximately 10(-6) s, concomitant with heme binding of a methionine residue. Kinetic modeling of time-resolved magnetic circular dichroism data further provides strong evidence that a 50-microseconds heme-histidine binding process proceeds in parallel with the faster pathway, implying that Met and His binding occur in different conformational ensembles of the protein, i.e., along respective ultrafast (microseconds) and fast (milliseconds) folding pathways. This kinetic heterogeneity appears to be intrinsic to the diffusional nature of early folding dynamics on the energy landscape, as opposed to the late-time heterogeneity associated with nonnative heme ligation and proline isomers in cytochrome c.

Animals↗
PubMed1999

Proteins of the exocytotic core complex mediate platelet alpha-granule secretion. Roles of vesicle-associated membrane protein, SNAP-23, and syntaxin 4.

To understand the molecular basis of granule release from platelets, we examined the role of vesicle-associated membrane protein, SNAP-23, and syntaxin 4 in alpha-granule secretion. A vesicle-associated membrane protein, SNAP-23, and syntaxin 4 were detected in platelet lysate. These proteins form a SDS-resistant complex that disassembles upon platelet activation. To determine whether these proteins are involved in alpha-granule secretion, we developed a streptolysin O-permeabilized platelet model of alpha-granule secretion. Streptolysin O-permeabilized platelets released alpha-granules, as measured by surface expression of P-selectin, in response to Ca2+ up to 120 min after permeabilization. Incubation of streptolysin O-permeabilized platelets with an antibody directed against vesicle-associated membrane protein completely inhibited Ca2+-induced alpha-granule release. Tetanus toxin cleaved platelet vesicle-associated membrane protein and inhibited Ca2+-induced alpha-granule secretion from streptolysin O-permeabilized platelets. An antibody to syntaxin 4 also inhibited Ca2+-induced alpha-granule release by approximately 75% in this system. These results show that vesicle-associated membrane protein, SNAP-23, and syntaxin 4 form a heterotrimeric complex in platelets that disassembles with activation and demonstrate that alpha-granule release is dependent on vesicle SNAP receptor-target SNAP receptor (vSNARE-tSNARE) interactions.

Antibodies↗
PubMed1999

Failure of ascorbate to protect against broadband blue light-induced retinal damage in rat.

BACKGROUND: Excessive generation of free radicals due to light absorption is proposed as the most likely mechanism for photochemical retinal damage. The observed reduction of green light-induced retinal injury after ascorbate treatment is believed to be an antioxidative effect. The aim of the present study was to evaluate the possible protection of ascorbate against blue light-induced photoreceptor damage. METHODS: Cyclic light-reared albino rats were injected intraperitoneally with either ascorbate (1 mg/g body weight) or, as placebo, physiological saline 24 h before and just prior to exposure to blue light. After 20-22 h of dark adaptation, two groups of the rats were exposed in pairs to the blue light (400-480 nm) for 6 h at an average irradiance of 0.7 W/m(2) in the cage. Six days after light exposure, all rats were killed and retinal samples were analyzed. RESULTS: Diffuse blue light irradiation resulted in an uneven distribution of damage in the retina. As judged from the pathological changes in the retina irradiated, no microscopic difference was observed between the two groups. The preserved thickness of the outer nuclear layer was on average 61.3% in the ascorbate-treated and 66.4% in the placebo-treated group. The photoreceptor loss was not significantly different between the two groups. CONCLUSION: The ascorbate did not protect the retina from blue-light induced damage. This favors the assumption that the mechanisms for blue light-induced retinal damage might differ from that for green light.

Animals↗