Biomedical subjects

Y J Wu

Publications and source records attributed to Y J Wu.

At least 19 recordsLinked to original sources

PubMed2003

Determination of dextromethorphan and its metabolite dextrorphan in human urine by capillary gas chromatography without derivatization.

A sensitive, simple and accurate method was developed for determination of dextromethorphan (DM) and dextrorphan (DT) in human urine by capillary gas chromatography without derivatization. After an oral dose of 30 mg DM, urine samples were collected and extracted, then analyzed on 0.22 mmx17 m HP-1 capillary column. DM and its metabolite DT were analyzed simultaneously with good separation. Docosane was used as the internal standard (I.S.). The detector used was flame ionization detector (FID). There was a linear relationship between peak area ratios of analytes to I.S. and concentration of analytes over the concentration range 0.37-7.38 micromol/l for DM and 0.39-77.8 micromol/l for DT. The recovery was 88.1 approximately 103.9% for DM and 86.7 approximately 96.8% for DT. The within-day and between-day coefficients of variation were less than 7.4 and 7.3% (RSD) for the assay of DM and DT in urine, respectively. The limits of detection (LOD) were 0.30 micromol/l for DM and 0.16 micromol/l for DT. The limits of quantitation (LOQ) were 0.37 micromol/l (RSD<6%) for DM and 0.39 micromol/l (RSD<7%) for DT. The method has been applied to determine the oxidative phenotypes of cytochrome P450 2D6 (CYP2D6) in a Chinese population with metabolic ratio of DM in human urine.

Adolescent↗

PubMed2003

Comparison of temporal filtering methods for dynamic contrast MRI myocardial perfusion studies.

Dynamic contrast myocardial perfusion studies may benefit from methods that speed up the acquisition. Unaliasing by Fourier encoding the overlaps using the temporal dimension (UNFOLD), and a similar linear interpolation method have been shown to be effective at reducing the number of phase encodes needed for cardiac wall motion studies by using interleaved sampling and temporal filtering. Here such methods are evaluated in cardiac dynamic contrast studies, with particular regard to the effects of the choice of filter and the interframe motion. Four different filters were evaluated using a motion-free canine study. Full k-space was acquired and then downsampled to allow for a measure of truth. The different filters gave nearly equivalent images and quantitative flow estimates compared to full k-space. The effect of respiratory motion on these schemes was graphically depicted, and the performance of the four temporal filters was evaluated in seven human subjects with respiratory motion present. The four filters provided images of similar quality. However, none of the filters were effective at eliminating motion artifacts. Motion registration methods or motion-free acquisitions may be necessary to make these reduced FOV approaches clinically useful.

Algorithms↗

PubMed2001

Neurotrophins are key mediators of the myelination program in the peripheral nervous system.

Although knowledge of the functions of neurotrophins has advanced rapidly in recent years, studies concerning the involvement of neurotrophins in glial-neuronal interactions rarely extend further than their roles in supporting the survival and differentiation of neuronal cells. In this study endogenous brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) were identified in Schwann cell/dorsal root ganglia neuronal cocultures and shown to modulate the myelination program of the peripheral nervous system. The differential expression of BDNF and NT3 were examined and compared with the expression profiles of myelin proteins in the cocultures throughout the myelination process. BDNF levels correlated with active myelin formation, whereas NT3 expression was initially high and then down regulated throughout the proliferation and premyelination periods. Addition of exogenous BDNF enhanced myelination, whereas the removal of the endogenous BDNF by using the BDNF receptor TrkB-Fc fusion protein inhibited the formation of mature myelin internodes. Interestingly, exogenous NT3 significantly inhibited myelination, whereas the removal of the endogenous NT3 by using the NT3 receptor TrkC-Fc fusion protein resulted in an enhancement similar to that obtained with the addition of BDNF. In addition, in vivo studies were performed during the development of the mouse sciatic nerve. Subcutaneous injections of BDNF resulted in an enhancement of myelin formation in the sciatic nerve, whereas the removal of the endogenous BDNF dramatically inhibited myelination. Injections of NT3 inhibited myelin formation, and the removal of the endogenous NT3 enhanced myelination. These results demonstrate that BDNF and NT3 possess different modulatory roles in the myelination program of the peripheral nervous system and that their mechanisms of action are specific and highly regulated.

Animals↗

PubMed2001

Macrophage accumulation associated with rat cardiac allograft rejection detected by magnetic resonance imaging with ultrasmall superparamagnetic iron oxide particles.

BACKGROUND: Acute cardiac allograft rejection continues to be the cause of graft loss and contributes to the morbidity and mortality after cardiac transplantation. In this study, we report a new method for detecting organ rejection in transplantation with an MR-based technique using dextran-coated ultrasmall superparamagnetic iron oxide (USPIO) particles. These particles ( approximately 27 nm in diameter) are known to shorten relaxation times in MRI experiments. METHODS AND RESULTS: A new rat model of heterotopic heart and lung transplantation has been developed for MRI experiments. Allotransplantations (DA-->BN) were performed (n=8), with syngeneic transplantations (BN-->BN) serving as controls (n=8). MR images were obtained with a gradient echo method. At postoperative day 7, allotransplants developed moderate rejection as determined histopathologically. A significant reduction in MR signal intensity was observed after USPIO injection into rats with allotransplanted hearts. Syngeneic transplants showed no differences in MR signal intensity before and after USPIO injections. After injection of USPIO particles at postoperative day 6, a group of allotransplanted rats was treated with cyclosporin A (3 mg/kg). Animals treated with cyclosporin A for 7 days showed no reduction in MR signal intensity after USPIO reinjection at day 14, whereas animals treated for 4 days showed a significant decrease in MR signal intensity in the transplanted hearts indicative of acute graft rejection. Pathological analysis of these animals revealed that dextran-coated USPIO particles were taken up by the infiltrating macrophages that accumulated within the rejecting cardiac graft. CONCLUSIONS: This MRI method offers promise as a noninvasive method for detecting transplant allograft rejection.

Animals↗

PubMed2001

Angiotensin-converting enzyme inhibitor preserves p21 and endothelial nitric oxide synthase expression in monocrotaline-induced pulmonary arterial hypertension in rats.

BACKGROUND: Pulmonary arterial hypertension (PAH) is associated with structural changes in the pulmonary vasculature characterized by the proliferation of cellular components of the vessels. ACE inhibitor (ACEI) may have beneficial effects in treating PAH, but its precise mechanism of action in the remodeling process is unclear. p21 is a cyclin-dependent kinase inhibitor that may have a protective role in this process by inhibiting cellular proliferation. Endothelial nitric oxide synthase (eNOS) has also been shown to be protective by its vasodilatory effect. Therefore, we investigated whether expression of p21 and eNOS was modulated by ACEI treatment in a rat model. METHODS AND RESULTS: Monocrotaline (MCT) was administered to 2 groups of Sprague-Dawley rats fed a high-cholesterol diet, ie, one group received MCT concomitantly with enalapril treatment (MCT(+)/ACEI(+) rats), and the other group did not receive enalapril (MCT(+)/ACEI(-) rats). After 5 weeks, MRI showed right ventricular hypertrophy in MCT(+)/ACEI(-) rats. MCT(+)/ACEI(+) rats showed a preserved right ventricular morphology. Isolated pulmonary perfusion studies showed that ACEI significantly upregulated NO production, as measured by nitrite levels. Addition of N-methyl-D-glucamine dithiocarbamate-Fe solution, an NO-trapping agent, reversed the basal vasodilatory effect of ACEI in the pulmonary vasculature. Immunoblot analysis showed decreased p21 and eNOS expression in the lung in MCT(+)/ACEI(-) rats, whereas their expression was preserved with enalapril treatment. CONCLUSIONS: ACEI suppresses the development of MCT-induced PAH in rats. The mechanism of action might involve the preservation of p21 and eNOS expression. Both p21 and endothelium-derived NO appear to have protective roles in the development of PAH.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2001

Energy expenditure of wheeling and walking during prosthetic rehabilitation in a woman with bilateral transfemoral amputations.

OBJECTIVE: To compare the energy expenditure of locomotion by wheelchair with that required for prosthetic ambulation in a person with bilateral transfemoral (TF) amputations. DESIGN: Observational, single patient, descriptive. SETTING: An 80-meter long rectangular hallway in a rehabilitation unit. PATIENT: A 41-year-old woman with bilateral TF amputations that were performed 79 days before her admission to the rehabilitation unit. MAIN OUTCOME MEASURES: The oxygen uptake, oxygen cost, heart rate, speed, cadence, and stride length of walking measured during a 4-month course of prosthetic rehabilitation. Five locomotion conditions were evaluated: (1) wheelchair propulsion, (2) walking with short-leg prostheses (stubbies) and a walker, (3) long-leg prostheses and a walker, (4) long-leg prostheses without knee mechanism and axillary crutches, and (5) long-leg prostheses with right polycentric knee and left locked knee and axillary crutches. A portable and telemetric system was used to measure the metabolic parameters. An arm ergometry graded exercise test was performed at the end of rehabilitation. RESULTS: Oxygen cost (range, 466%--707% of that of wheeling) and heart rate (range, 106%--116% of that of wheeling) were higher during walking with various combinations of prostheses and walking aids. The speed of prosthetic walking was only 24% to 33% of that of wheeling. Our patient preferred using a wheelchair to prosthetic walking after discharge. CONCLUSIONS: People with bilateral TF amputations require very high cardiorespiratory endurance to fulfill the energy demand during prosthetic rehabilitation. The high energy cost of prosthetic walking will limit its application in daily activities.

Accidents, Traffic↗

PubMed2001

Adult isolated hypoplasia of left pulmonary artery with exertional angina and abnormal exercise stress test: a case report and treatment implication.

Pulmonary artery hypoplasia, either congenital or acquired, is a rare abnormality seen in adults. We reported the first case of adult, isolated, left pulmonary artery hypoplasia, with exertional angina and prominent ST depression in exercise stress test, that seemed to be caused by exertional hypoxemia. Several vasodilators, including nitroglycerin, prostaglandin E1, and nifedipine, were administered individually, each with subsequent hemodynamic monitoring, pulse oximetric monitoring, and exercise test. Vasodilator administrations reduced pulmonary vascular resistance (baseline, 599; vasodilators, 306, 211, and 284 dyne x sec x m2/cm5, respectively) and attenuated ST depression (by 52, 72, and 27%, respectively) but without an immediate benefit on exercise tolerance. All vasodilators except nifedipine ameliorated exertional hypoxemia (expressed by arterial oxygen saturation during peak exercise, baseline, 69%; vasodilators, 85, 78, and 65%, respectively). Additional oxygen supply after nitroglycerin administration further benefited exertional hypoxemia (arterial oxygen saturation, 96%) and exercise ST depression (attenuated by 82%).

Angina Pectoris↗

PubMed2001

Enhanced susceptibility to pulmonary infection with Burkholderia cepacia in Cftr(-/-) mice.

Progressive pulmonary infection is the dominant clinical feature of cystic fibrosis (CF), but the molecular basis for this susceptibility remains incompletely understood. To study this problem, we developed a model of chronic pneumonia by repeated instillation of a clinical isolate of Burkholderia cepacia (genomovar III, ET12 strain), an opportunistic gram-negative bacterium, from a case of CF into the lungs of Cftr (m1unc-/-) (Cftr(-/-)) and congenic Cftr(+/+) controls. Nine days after the last instillation, the CF transmembrane regulator knockout mice showed persistence of viable bacteria with chronic severe bronchopneumonia while wild-type mice remained healthy. The histopathological changes in the lungs of the susceptible Cftr(-/-) mice were characterized by infiltration of a mixed inflammatory-cell population into the peribronchiolar and perivascular spaces, Clara cell hyperplasia, mucus hypersecretion in airways, and exudation into alveolar airspaces by a mixed population of macrophages and neutrophils. An increased proportion of neutrophils was observed in bronchoalveolar lavage fluid from the Cftr(-/-) mice, which, despite an increased bacterial load, demonstrated minimal evidence of activation. Alveolar macrophages from Cftr(-/-) mice also demonstrated suboptimal activation. These observations suggest that the pulmonary host defenses are compromised in lungs from animals with CF, as manifested by increased susceptibility to bacterial infection and lung injury. This murine model of chronic pneumonia thus reflects, in part, the situation in human patients and may help elucidate the mechanisms leading to defective host defense in CF.

Animals↗

PubMed2001

Recent developments on ketolides and macrolides.

Recent semi-synthetic studies of erythromycin A culminated in the discovery of two ketolide drug candidates, HMR-3647 and ABT-773, for the treatment of community-acquired bacterial infections caused by both macrolide- and beta-lactam-susceptible and -resistant S. pneumoniae, gram negative bacteria, and intracellular atypical pathogens. The discovery of ketolides has rekindled interest in macrolides, and recent efforts have also led to a novel class of 4''-carbamates with activity against macrolide-resistant organisms. This review is an account of recent developments on ketolides and macrolides in terms of both chemistry and antibacterial activity.

Animals↗

PubMed2001

On-column amperometric detection of ofloxacin and pasiniazid in urine by capillary electrophoresis with an improved fractured joint and small detection cell.

An improved high-voltage electric field isolating joint and small detection cell have been carefully designed and fabricated. The joint possesses short steady time, high electric conductance efficiency and high performance. The cell is convenient to install and remove the capillaries with and without the joint, as well as to fix, adjust and insert the microelectrode into the detection capillary. Using the joint and the cell, an analytical method for determination of ofloxacin (Oflx) and pasiniazid (Ipa) in urine by capillary electrophoresis with on-column amperometric detection was developed. The calibration lines were linear in the range of 10-100 mg l-1 of Oflx and 1.0-50 mg l-1 of Ipa, respectively. The detection limits were 8.5 mg l-1 of Oflx and 0.80 mg l-1 of Ipa. Their recovery ranged from 101 to 104%. The accuracy and intra-day and inter-day reproducibility of Oflx and Ipa were determined with satisfactory results. This method was successfully used for determining Oflx and Ipa in human urine.

Aminosalicylic Acid↗

PubMed2001

[Expression of heme oxygenase-1 in neonatal rat cardiocytes induced by lipopolysaccharide].

To study the alterations of heme oxygenase-1 mRNA in neonatal rat cardiomyocytes (NRCMs) induced by lipopolysaccharide (LPS) and the role of heme oxygenase-1 (HO-1) in the LPS induced disorders of myocardium function, 10 (L, 6 h), 30 (M, 6 h), 50 micrograms/ml (H, 6 h) LPS and 10 micrograms/ml LPS + 10 mumol/ml Zn-protoporphyrin-IX (ZnPPIX; L + I, 6 h) and 10 mumol/ml ZnPPIX alone (I, 6 h) were added to the medium for a 6-hour culture of NRCMs, and 10 micrograms/ml LPS for 9 h (L, 9 h) and 18 h (L, 18 h) cultures. LDH release and MDA contents of the cells were measured. When NRCMs were collected, Trypan blue stain method was used to examine the mortality (the rate of Trypan blue uptake) of NRCMs. HO-1 mRNA expression was examined by Northern blot. The results showed that HO-1 mRNA expression of NRCMs increased gradually along with the increase of LPS concentration below the level of 30 micrograms/ml. When the final concentrations of LPS were 10 and 30 micrograms/ml, the HO-1 mRNA expression of NRCMs increased by 81.2% and 126.3% respectively compared with control. When the final concentration of LPS was 50 micrograms/ml, the HO-1 mRNA expression decreased to the level of 10 micrograms/ml group. When the final concentration was 10 micrograms/ml, the HO-1 mRNA expression increased gradually along with the culture time. After a 9- or 18-hour culture, the HO-1 mRNA expression of NRCMs increased by 93.6% and 105.8% respectively compared with control. Only when NRCMs had been cultured with 30, 50 micrograms/ml LPS and 10 micrograms/ml LPS + 10 mumol/ml ZnPPIX for 6 h and 10 micrograms/ml LPS for 18 h, the rate of Trypan blue stain uptake, MDA contents and LDH release significantly increased. With 10 micrograms/ml LPS alone and 10 mumol/ml ZnPPIX alone for 6 h, the above parameters were not significantly increased (P > 0.05). The results demonstrate that LPS induces HO-1 mRNA expression of NRCMs dose- and time-dependently to some extent. The inducible HO can protect NRCMs from injury and thus play an important role in pathogenesis of myocardium under LPS.

Animals↗

PubMed2001

Correlation of acoustic velocity of synovial fluid with markers of inflammation in arthritic patients.

Analysis of synovial fluid is important in the evaluation and treatment of arthritic conditions. This study measured the acoustic velocity of synovial fluids in patients with degenerative joint diseases, crystal arthropathy, and other inflammatory arthropathies using the ultrasonic pulse-echo method. The measured acoustic velocities of these bio-fluids were then correlated with clinical parameters including the synovial white blood cell count (WBC), clarity, viscosity, string test, erythrocyte sedimentation rate (ESR), and serum C-reactive protein (CRP). Results showed that the acoustic velocities were correlated with ESR (p = 0.0016) and CRP (p = 0.0001). The mean acoustic velocity of inflammatory synovial fluids, defined as synovial fluids with WBCs of more than 2000/mm3, was greater than that of synovial fluids with WBCs of less than 2000/mm3 (1550 +/- 4.5 m/s vs 1544 +/- 1.5 m/s, p = 0.007). This study demonstrated that the acoustic velocity of synovial fluid correlates well with severity of inflammation. These findings suggest that measurement of acoustic velocity may be useful in the clinical evaluation and management of arthritic conditions.

Arthritis↗

PubMed2001

Effect of recombinant human basic fibroblast growth factor on acute inflammation in mice and rats.

AIM: To investigate the anti-inflammatory effects of recombinant human basic fibroblast growth factor (rh-bFGF). METHODS: Several inflammation models such as croton oil-induced ear swelling, carrageenan-induced hind paw edema, and acute peritonitis in rats or mice were prepared. Superoxide dismutase (SOD) activity was measured by hydroxyamine method, nitric oxide (NO) concentration by Griess reaction assay, nitric oxide synthase (NOS) activity by NADPH-diaphoras stain assay, N-acetyl-beta- D-glucosaminidase (NAG) activity by colorimetry, prostaglandin E2 (PGE2) production by radioimmunoassay (RIA), malondialdehyde (MDA) content by thiobarbituric acid (TBA) fluorescence technique, and protein content by Coomassie brilliant blue method in peritoneal exudate in rats. RESULTS: Recombinant human bFGF 2, 4 kU/kg im inhibited croton oil-induced ear swelling and carrageenan-induced paw edema in mice. In addition, rh-bFGF 2, 4 kU/kg im reduced neutrophil counts in the rat peritoneal exudate, and lessened protein content in peritoneal exudate in rats and mice. In the rat peritonitis induced by carrageenan, rh-bFGF 4 kU/kg decreased the MDA and NO levels, inhibited the NOS activity, augmented the SOD activity, and lowered the production of PGE(2) in exudate. However, rh-bFGF had no effect on NAG content. CONCLUSION: Recombinant human bFGF has an anti-inflammatory effect and its mechanisms are related to the inhibition of NOS activity, reduction of NO, MDA, and PGE(2) content, and increase of SOD activity.

Animals↗

PubMed2001

Effects of recombinant human basic fibroblast growth factor on restenosis after arterial endothelial injury in rats.

AIM: To study the preventive effect of recombinant human basic fibroblast growth factor (rh-bFGF) on restenosis after percutaneous transluminal coronary angioplasty (PTCA). METHODS: Sixty male Wistar rats were randomly divided into sham operation group, intima injured group, and intima injured plus rh-bFGF treated group. Rat carotid arteries were injured using a balloon catheter except sham operation group. The rats of rh-bFGF treated group were injected im rh-bFGF 10 kU . kg-1 . d-1 after intima was injured. Ten rats in each group were killed on d 7 and d 14 after injury, respectively. [3H]Thymidine incorporation assay and pathological examination were carried out to each vessel. RESULTS: (1) Seven days after injury, the average intimal thickness in sham operation group, intima injured group, and rh-bFGF treated group was (7 +/- 1), (32 +/- 11), and (17 +/- 3) micron; average intimal area was (384 +/- 145), (1530 +/- 817), and (586 +/- 185) micron2; the numbers of smooth muscle cells in neointima per transect were 0 +/- 0, 146 +/- 18, and 105 +/- 26; the ratio of the collagen area to intimal area plus medial area were 0.29 +/- 0.09, 0.7 +/- 0.3, and 0.30 +/- 0.14; [3H]thymidine incorporation were (17 +/- 6), (62 +/- 23), (20 +/- 8) kBq/g tissue, respectively. (2) Fourteen days after injury, the average intimal thickness of sham operation group, intima injured group, and rh-bFGF treated group was (8 +/- 1), (41 +/- 9), and (20 +/- 3) micron; average intimal area was (391 +/- 134), (1761 +/- 337), and (731 +/- 124) micron2; the numbers of smooth muscle cells in neointima per transect were 0 +/- 0, 145 +/- 9, and 102 +/- 6; the ratio of collagen area to intimal area plus medial area were 0.28 +/- 0.14, 0.59 +/- 0.21, and 0.38 +/- 0.03; [3H]thymidine incorporation was (15 +/- 4), (57 +/- 11), and (22 +/- 6) kBq/g tissue, respectively. CONCLUSION: Large dosage of rh-bFGF inhibits neointimal hyperplasia and reduces restenosis after balloon injury.

Angioplasty, Balloon, Coronary↗

PubMed2001

Anti-inflammatory effect and mechanism of proanthocyanidins from grape seeds.

AIM: To investigate the anti-inflammatory effect and mechanism of proanthocyanidins (PA) from grape seeds. METHODS: Croton oil-induced ear swelling in mice and carrageenan-induced hind paw edema in rats were prepared. The nitric oxide synthase (NOS) activity was measured by NADPH-diaphoras stain assay, nitric oxide (NO) content by Griess diazotization assay, N-acetyl-beta- D-glucosaminidase (beta-NAG) activity by spectrophotography, malondialdehyde (MDA) content by thiobarbituric acid (TBA) fluorescence technique, and IL-1beta, TNFalpha, and PGE2 content by radioimmunoassay (RIA). RESULTS: PA 10-40 mg/kg ip inhibited carrageenan-induced paw edema in rats and croton oil-induced ear swelling in mice in a dose-dependent manner. PA 10 mg/kg reduced MDA content in inflamed paws, inhibited beta-NAG and NOS activity, and lowered the content of NO, IL-1beta, TNFalpha, and PGE2 in exudate from edema paws of rats induced by carrageenan. The inhibitory effect of PA on all above indices was more evident than that of dexamethasone 2 mg/kg. CONCLUSION: PA has anti-inflammatory effect on experimental inflammation in rats and mice. Its mechanisms of anti-inflammatory action are relevant to oxygen free radical scavenging, anti-lipid peroxidation, and inhibition of the formation of inflammatory cytokines.

Animals↗

PubMed2001

[Clinical observation on small doses Tripterygium wilfordii polyglycoside combined with methotrexate in treating rheumatoid arthritis].

OBJECTIVE: To observe the effect and adverse reaction of small doses Tripterygium wilfordii polyglycoside (TWP) combined with methotrexate (MT) in treating rheumatoid arthritis (RA). METHODS: Seventy RA patients were randomly divided into two groups, the control group (35 patients) and the TWP combined MT Group (TWPM group). Both of them were continued to use the non-steroidal anti-inflammatory drugs. The control group took MT 15 mg orally, once every week; the TWPM group took TWP 10 mg orally, 3 times a day, and MT 7.5 mg orally once every week. The clinical effect and adverse reaction after treatment were evaluated. RESULTS: The markedly effective rate in the control group and the TWPM group was 28.6% and 34.3% respectively, with no significant difference (P > 0.05). Data of symptoms and signs, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) were determined respectively with significant difference (P < 0.01). The rate of adverse reaction was 20 cases-times in the control group and 8 cases-times in the TWPM group. CONCLUSION: MT combined small doses of TWP in treating RA has better effect and less adverse reactions than un-combined MT.

Adult↗

PubMed2000

The C termini of Arabidopsis cryptochromes mediate a constitutive light response.

Cryptochrome blue light photoreceptors share sequence similarity to photolyases, flavoproteins that mediate light-dependent DNA repair. However, cryptochromes lack photolyase activity and are characterized by distinguishing C-terminal domains. Here we show that the signaling mechanism of Arabidopsis cryptochrome is mediated through the C terminus. On fusion with beta-glucuronidase (GUS), both the Arabidopsis CRY1 C-terminal domain (CCT1) and the CRY2 C-terminal domain (CCT2) mediate a constitutive light response. This constitutive photomorphogenic (COP) phenotype was not observed for mutants of cct1 corresponding to previously described cry1 alleles. We propose that the C-terminal domain of Arabidopsis cryptochrome is maintained in an inactive state in the dark. Irradiation with blue light relieves this repression, presumably through an intra- or intermolecular redox reaction mediated through the flavin bound to the N-terminal photolyase-like domain.

Alleles↗

PubMed2000

On-column amperometric detection in capillary electrophoresis with an improved high-voltage electric field decoupler.

An improved fabrication method for a decoupler for on-column amperometric detection in capillary electrophoresis (CE) is described. The decoupler is fabricated by etching one side-wall of the capillary with hydrofluoric acid after the polymer coating had been etched by laser, then the etched hole is sealed with adhesive. The steady time, electric conductivity efficiency and performance are investigated. On-column amperometric detection by CE of para-substituted phenols was carried out by coupling with a carbon-fiber microelectrode (10-microm diameter) and a practical small electrochemical detection cell.

Electrochemistry↗