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Biomedical subjects

R Gu

Publications and source records attributed to R Gu.

At least 19 recordsLinked to original sources
PubMed2006

Chinese medicinal herbs for measles.

BACKGROUND: Measles is an infectious disease caused by Morbillivirus. Chinese physicians believe that medicinal herbs are effective in alleviating symptoms and preventing complications. Chinese herbal medicines are dispensed according to the particular symptoms. OBJECTIVES: To assess the effectiveness and possible adverse events of Chinese medicinal herbs in treating measles. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Clinical Trials (CENTRAL) (The Cochrane Library Issue 4, 2005); MEDLINE (1966 to June 2005); EMBASE (1980 to June 2005); the Chinese Biomedical Database (1976 to June 2005); VIP Information (1989 to June 2005); China National Knowledge Infrastructure (CNKI) (1994 to June 2005); and the metaRegister of Controlled Trials was searched for ongoing trials. SELECTION CRITERIA: Randomised controlled trials (RCTs) in which patients with measles without complications were treated with Chinese medicinal herbs were included. DATA COLLECTION AND ANALYSIS: The primary outcome measure was death from any cause. The secondary outcome measure was improvement of overall symptoms. The tertiary outcome measure was fever clearance time. MAIN RESULTS: We identified 28 trials which claimed to use random allocation. Nineteen study authors were contacted by telephone and we discovered that the allocation methods they had used were not actually randomised. Three studies were excluded because the patients experienced complications. We were unable to contact the remaining six authors. These require further assessment and have been allocated to the 'Studies awaiting assessment' section. AUTHORS' CONCLUSIONS: Two authors independently assessed trial quality and extracted data. We interviewed by telephone the study authors for missing information regarding random allocation of the study process. Some trials allocated the participants according to the sequence they were admitted to the trials, that is to say, by using a pseudo-random allocation method. None of the trials concealed the allocation or blinding method. We hope future randomised controlled trials (RCTs) in this field will be conducted.

Adult↗
PubMed2001

Role of 20-HETE in mediating the effect of dietary K intake on the apical K channels in the mTAL.

We have used the patch-clamp technique to study the effect of dietary K intake on the apical K channels in the medullary thick ascending limb (mTAL) of rat kidneys. The channel activity, defined by the number of channels in a patch and the open probability (NPo), of the 30- and 70-pS K channels, was 0.18 and 0.11, respectively, in the mTAL from rats on a K-deficient diet. In contrast, NPo of the 30- and 70-pS K channels increased to 0.60 and 0.80, respectively, in the tubules from animals on a high-K diet. The concentration of 20-hydroxyeicosatetraenoic acid (20-HETE) measured with gas chromatography-mass spectrometry was 0.8 pg/microg protein in the mTAL from rats on a high-K diet and increased significantly to 4.6 pg/microg protein in the tubules from rats on a K-deficient diet. Addition of N-methylsulfonyl-12,12-dibromododec-11-enamide (DDMS) or 17-octadecynoic acid (17-ODYA), agents that inhibit the formation of 20-HETE, had no significant effect on the activity of the 30-pS K channels. However, DDMS/17-ODYA significantly increased the activity of the apical 70-pS K channel from 0.11 to 0.91 in the mTAL from rats on a K-deficient diet. In contrast, inhibition of the cytochrome P-450 metabolism of arachidonic acid increased NPo from 0.64 to 0.81 in the tubules from animals on a high-K diet. Furthermore, the sensitivity of the 70-pS K channel to 20-HETE was the same between rats on a high-K diet and on a K-deficient diet. Finally, the pretreatment of the tubules with DDMS increased NPo of the 70-pS K channels in the mTAL from rats on a K-deficient diet to 0.76. We conclude that an increase in 20-HETE production is involved in reducing the activity of the apical 70-pS K channels in the mTAL from rats on a K-deficient diet.

Amides↗
PubMed2001

Effect of dietary K intake on apical small-conductance K channel in CCD: role of protein tyrosine kinase.

We have used Western blot to examine the expression of cSrc protein tyrosine kinase (PTK) and protein tyrosine phosphatase (PTP)-1D in the renal cortex, and the patch-clamp technique to determine the role of PTK in mediating the effect of dietary K intake on the small-conductance K (SK) channel in the cortical collecting duct (CCD). When rats were on a K-deficient (KD) diet for 1, 3, 5, and 7 days, the expression of cSrc increased by 40, 90, 140, and 135%, respectively. In contrast, the expression of cSrc in the renal cortex from rats on a high-K (HK) diet for 1, 2, and 3 days decreased by 40, 60, and 75%, respectively. However, the protein level of PTP-1D was not significantly changed by dietary K intake. The addition of 1 microM herbimycin A increased NP(o), a product of channel number (N) and open probability (P(o)) in the CCD from rats on a normal diet or on a KD diet. The increase in NP(o) was 0.30 (normal), 0.45 (1-day KD), 0.65 (3-day KD), 1.55 (5-day KD), and 1.85 (7-day KD), respectively. Treatment of the CCD with herbimycin A from rats on a KD diet increased NP(o) per patch from the control value (0.7) to 1.4 (1-day KD), 1.6 (3-day KD), 2.6 (5-day KD), and 3.5 (7-day KD), respectively. In contrast, HK intake for as short as 1 day abolished the effect of herbimycin A. Furthermore, the expression of ROMK channels in the renal cortex was the same between rats on a KD diet or on a HK diet. Moreover, treatment with herbimycin A did not further increase NP(o) in the CCDs from rats on a HK diet. We conclude that dietary K intake plays a key role in regulating the activity of the SK channels and that PTK is involved in mediating the effect of the K intake on channel activity in the CCD.

Animals↗
PubMed2001

[New progress of surface enhanced Raman spectroscopic studies on a gold electrode in a nonaqueous system].

Based on a highly sensitive new generation confocal microprobe Raman system, the adsorption behavior of thiocyanate (SCN-) on a gold electrode in methanol solution was investigated by SERS for the first time. Preliminary results demonstrated that the interaction between SCN- and the electrode is so strong that its SERS signal can be detected in the whole research potential region (-0.1 V(-)-1.4 V). The orientation change may occur in the potential range -0.6 V-0.7 V. From -0.1 V to -0.6 V SCN- is adsorbed mainly through S end onto Au surface while in the potential range of -0.7 V to -1.2 V it is oriented mainly through N end. The potential dependence of the Raman frequency of nu CN resulted in two different values of electrochemical Stark effect, suggesting the existence of molecular orientation change.

Electrochemistry↗
PubMed2000

Regulation of ROMK1 channels by protein-tyrosine kinase and -tyrosine phosphatase.

We have used the two-electrode voltage clamp technique and the patch clamp technique to investigate the regulation of ROMK1 channels by protein-tyrosine phosphatase (PTP) and protein-tyrosine kinase (PTK) in oocytes coexpressing ROMK1 and cSrc. Western blot analysis detected the presence of the endogenous PTP-1D isoform in the oocytes. Addition of phenylarsine oxide (PAO), an inhibitor of PTP, reversibly reduced K(+) current by 55% in oocytes coinjected with ROMK1 and cSrc. In contrast, PAO had no significant effect on K(+) current in oocytes injected with ROMK1 alone. Moreover, application of herbimycin A, an inhibitor of PTK, increased K(+) current by 120% and completely abolished the effect of PAO in oocytes coexpressing ROMK1 and cSrc. The effects of herbimycin A and PAO were absent in oocytes expressing the ROMK1 mutant R1Y337A in which the tyrosine residue at position 337 was mutated to alanine. However, addition of exogenous cSrc had no significant effect on the activity of ROMK1 channels in inside-out patches. Moreover, the effect of PAO was completely abolished by treatment of oocytes with 20% sucrose and 250 microg/ml concanavalin A, agents that inhibit the endocytosis of ROMK1 channels. Furthermore, the effect of herbimycin A is absent in the oocytes pretreated with either colchicine, an inhibitor of microtubules, or taxol, an agent that freezes microtubules. We conclude that PTP and PTK play an important role in regulating ROMK1 channels. Inhibiting PTP increases the internalization of ROMK1 channels, whereas blocking PTK stimulates the insertion of ROMK1 channels.

Alanine↗
PubMed2000

Protein-tyrosine phosphatase reduces the number of apical small conductance K+ channels in the rat cortical collecting duct.

Previous studies have demonstrated that an increase in the activity of protein-tyrosine kinase (PTK) is involved in the down-regulation of the activity of apical small conductance K(+) (SK) channels in the cortical collecting duct (CCD) from rats on a K(+)-deficient diet (). We used the patch clamp technique to investigate the role of protein-tyrosine phosphatase (PTP) in the regulation of the activity of SK channels in the CCD from rats on a high K(+) diet. Western blot analysis indicated that PTP-1D is expressed in the renal cortex. Application of 1 microm phenylarsine oxide (PAO) or 1 mm benzylphosphonic acid, agents that inhibit PTP, reversibly reduced channel activity by 95%. Pretreatment of CCDs with PAO for 30 min decreased the mean NP(o) reversibly from control value 3.20 to 0.40. Addition of 1 microm herbimycin A, an inhibitor of PTK, had no significant effect on channel activity in the CCDs from rats on a high K(+) diet. However, herbimycin A abolished the inhibitory effect of PAO, indicating that the effect of PAO is the result of interaction between PTK and PTP. Addition of brefeldin A, an agent that blocks protein trafficking from Golgi complex to the membrane, had no effect on channel activity. Moreover, application of colchicine, a microtubule inhibitor, or paclitaxel, a microtubule stabilizer, had no effect on channel activity. In contrast, PAO still reduced channel activity in the presence of brefeldin A, colchicine, or paclitaxel. Furthermore, the effect of PAO on channel activity was absent when the tubules were bathed in 16% sucrose-containing bath solution or treated with concanavalin A. We conclude that PTP is involved in the regulation of the activity of SK channels and that inhibition of PTP may facilitate the internalization of the SK channels.

Animals↗
PubMed2000

[Cochlear hypoxia and mtDNA deletion: possible correlated factors to cause presbycusis].

OBJECTIVE: To find the relationship among the most common mitochondrial DNA (mtDNA) 4,977 bp deletion, aging and deterioration of acoustic organ and determine the pathologic factors causing mtDNA 4,977 bp deletion. METHODS: Sixty-seven temporal bones from a presbycusis group, an age-matched control group and a young control group were evaluated. The nested PCR and tri-nested PCR techniques were used to test the presence of mtDNA 4,977 deletion. Computer imaging processing was used to measure the parameters of blood vessels in the internal acoustic meatus. RESULTS: Temporal bones from patients aged 50 years or over frequently showed mtDNA 4,977 deletions. In presbycusis patients, 17 of 34 ears showed mtDNA 4,977 deletion, whereas only 4 of 19 ears from the age-matched control group showed mtDNA 4,977 deletions. mtDNA 4,977 deletions were often seen in the spiral ganglion and vestibular ganglion neurons. In the presbycusis group, the lumen of the vasa nervosum of the internal auditory meatus showed a more severe reduction in patients with mtDNA 4,977 deletion than in those without deletion. CONCLUSION: There is a strong correlation between presbycusis and mtDNA 4,977 deletion. We hypothesize that cochlear hypoxia may cause mtDNA 4,977 deletions and other mtDNA mutants which in turn may cause a reduction of mitochondrial oxidative phosphorylation and decreased auditory nerve function. The symptoms of neural presbycusis, however, may appear only after mtDNA metabolism decreases below a specific threshold.

Aged↗
PubMed2000

[Dynamic analysis of junctional sequences of T cell receptor (TCR) delta and gamma gene rearrangement in childhood with acute lymphoblastic leukemia].

OBJECTIVE: To explore the junctional sequence difference of T cell receptor delta and gamma gene rearrangement in childhood acute lymphoblastic leukemia (ALL) at diagnosis, complete remission (CR) and relapse. METHODS: By using the T-vector molecular cloning and sequencing and polymerase chain reaction, the junctional sequences of TCRdeltaV-D and TCRgammaV-J were dynamically analyzed in 34 bone marrow samples of ALL. RESULTS: The junctional sequence of TCR delta, gamma gene showed significant difference and regularity before and after remission and during relapsed periods. The sequence of TCRdeltaV-D were analyzed in 24 samples from ALL. Among them, the intact Vdelta2 and 5'Ddelta3 sequences were observed in 10 samples at diagnosis, of which 7 samples had T-->C mutation in Ddelta3 nonamer sequence. The deletions of rearranged Vdelta2, 5'Ddelta3 and Ddelta3 haptamer sequences were found in 11 complete remission (CR) samples with ALL, but none had T-->C mutation in Ddelta3 nonamer sequence. The deletion rate of Vdelta2 or Ddelta3 sequences and the T-->C mutation in Ddelta3 nonamer sequence were extremely differed between samples at diagnosis and in remission (calculate exact probabilities P = 0.001). The junctional rearrangement sequence of 5'Ddelta3 sequences tended to remain intact in 3 relapsed samples. The findings of TCRgammaV-J sequences were similar to that of TCRdeltaV-D in 10 ALL patients. CONCLUSION: The difference of TCRdeltaV-D and TCRgammaV-J junctional sequences were related to the development, therapeutic effectiveness and outcome in ALL.

Child↗
PubMed2000

[Central low frequency hearing loss].

OBJECTIVE: To study the pathogenesis of the bilateral central low frequency hearing loss. METHODS: Audiologic findings [auditory brainstem response(ABR), evoked otoacoustic emission (EOAE), et al] of 101 cases with bilateral central low frequency hearing loss were studied. RESULTS: The typical clinical manifestations of bilateral central low frequency hearing loss were normal EOAE which cannot be suppressed by contralateral white noise, abnormal ABR, no acoustic reflex and--SP/AP > 0.44. CONCLUSIONS: The results suggest that cochlear outer hair cells are normal in function with dysfunction of the cochlear nuclei. The main lesion of the disease are neural pathways related to Acoustic reflex and medial olivo-cochlear efferent nervous system. The cochlear afferent nerve may also be involved.

Adolescent↗
PubMed2000

[Two-dimensional surface Raman imaging of a roughened iron electrode in saline solution].

By using a confocal microprobe Raman system and proper surface roughening procedure for iron, the pit corrosion behavior of bare iron electrode in 3.4% NaCl (saline solution) solution has been investigated. The surface-enhanced Raman scattering (SERS) spectra of the corrosion products due to the pit corrosion at positive potential was obtained with high ratio of signal to noise. The application of SERS technique has been extended successfully to the study of iron corrosion. The two-dimensional surface Raman imaging acquired at 660 cm-1 was obtained also with the utility of surface Raman image technique. Results show that different iron oxides should coexist in the pit corrosion region and the distribution of the corrosion products was not uniform.

Chemical Phenomena↗
PubMed2000

[Self-assembly of nano-structured silver particle and its surface-enhanced Raman spectroscopic application].

Planar arrays of nano-structured silver particle were self-assembled on poly-lysine modified glass surfaces. SEM characterization indicates that silver particles were assembled as a sub-monolayer. A comparison of the UV/Vis spectra of silver colloid and the arrays demonstrates that the poly-lysine layer showed size selectivity for the self-assembling silver particles. Surface-enhanced FT-Raman spectrum of methylviolegen on the array reveals that Raman scattering in near IR region was mainly enhanced via a chemical enhancement mechanism.

Colloids↗
PubMed2000

[Resonance Raman and surface-enhanced Raman spectroscopic study of microperoxidase-11].

The electron transfer and structure of microperoxidase-11 (MP-11) in solution and at electrode/solution interface were studied by electrochemical, resonance Raman and surface-enhanced Raman spectroscopic techniques. Results show that the central iron in heme group was six-coordinated in solution, whereas it was converted to five-coordinated state as MP-11 was adsorbed on the surface of a roughened silver electrode, due to the reorientation of MP-11 molecules. The electrochemical properties of MP-11 were directly affected by the coordination state of heme iron.

Electrochemistry↗
PubMed1999

Development of Weather-Dependent Flow Requirements for River Temperature Control.

/ Streamflow influences biological processes, habitat, and ecological integrity of streams in a number of vital ways. The establishment of weather-dependent minimum flows is essential to the protection of the aquatic environment and wildlife habitat from the adverse impacts of high water temperatures and to the effective utilization of the assimilative capacity of instream flows. In this study, weather-dependent flow requirements for summer river temperature control are derived from quantitative temperature-flow relationships. Correlation and regression of historical data and an analytical solution to the basic heat balance equation are employed to quantify the impacts of stream flow on river temperatures. Five-year continuous field measurements from the Platte River, Nebraska, USA, are used to illustrate the practical application in water-quality management. The methods and results demonstrate the feasibility of temperature control through streamflow management to meet water temperature standards and protect the aquatic biota by setting the appropriate weather-related minimum river discharges. The flow requirements are evaluated by a comparison with a critical discharge. Information provided in this paper will assist in planning streamflow regulation, design of river and reservoir operations, and application of water-quality criteria in environmental management.KEY WORDS: River discharges; Flow management; Habitat; Water quality; Weather; Wildlifehttp://link.springer-ny.com/link/service/journals/00267/bibs/24n4p529.html</HEA

Journal Article↗
PubMed1999

[Omega-mercaptohexanoic acid self-assemble-modified gold electrode and its catalytic property for redox reaction of chlorophylls].

Omega-mercaptohexanoic acid (6-MHA) self-assemble-modified gold electrode has been made by the authors. The SERS spectrum and the variations of double-layer capacitance (Cd) which occurred in the formation of 6-MHA self-assembled monolayers (SAM) on gold electrode surface were studied. The structure model of this SAM was deduced. The results show that 6-MHA can form stable SAM on gold electrode, and this 6-MHA SAM electrode has obvious catalysis for the redox reaction of chlorophylls.

Caproates↗
PubMed1999

[Progress of surface enhanced Raman spectroscopic studies in nonaqueous systems].

In this report, we describe the applications and theoretical aspects of SERS phenomenon in nonaqueous systems, which mainly involves the structure of solid/nonaqueous system, the adsorption of some neutral and organic molecules, inorganic ions and other complex compound molecules, the process and mechanism of some electrochemical oxidation reduction reactions in organic solvents etc.. In this review, we also depict the similarities and differences in SER spectra of aqueous and non-aqueous systems.

English Abstract↗
PubMed1998

Effects of impulse noise on cortical response threshold and inner ear activity of succinic dehydrogenase and acetylcholinesterase in guinea pigs.

The effects of impulse noise (firecrackers at 170 dB SPL, 1, 10, 20 rounds) on auditory cortical response threshold (CRT) and activity of succinic dehydrogenase (SDH) and acetylcholinesterase (AchE) in the inner ear were studied in 37 guinea pigs. The results showed that extent of damage in the cochlea was related to amount of exposure to the noise. Exposure to 10 rounds resulted in temporal threshold shift (TTS); to 20 rounds the result was permanent threshold shift (PTS). For the period when TTS existed, inverse correlation was noticed between enzyme activity change and CRT shift. The correlation could not be established when PTS was induced. The results suggest that the pathomechanism of PTS was more complex than that of TTS. The significance of the results is discussed.

Acetylcholinesterase↗
PubMed1998

[An ELISA assay for humulus scandens specific IgE antibodies].

OBJECTIVE: Humulus scandens pollen (HSP) has been proved to be the one of the most important causative factors of autumnal hay fever in China. We established an enzyme immunoassay for specific IgE against HSP by using monoclonal anti-IgE antibody to detect sIgE in 143 patients with autumnal hay fever and 30 healthy volunteers. METHODS: An indirect method of ELISA was developed. The optimal conditions for the test were: coating the allergen at 4 degrees C overnight with a concentration of 12 micrograms/ml; the test serum was diluted 1:16 and incubated with allergen overnight at 37 degrees C; the most suitable dilution and incubative time of the peroxidase-conjugated mouse anti-human IgE antibody were 1:3,000 and 2 hours respectively. RESULTS: The patients' serum level of sIgE was significantly higher than controls (P < 0.001) and correlated significantly with the degree of skin test reaction (P < 0.01). The concordance between the results of skin test and ELISA was 74%-83%. The specificity of the assay was confirmed by heat inactivation and multiple absorption experiments. The coefficients of variation for the intraassay and interassay reproducibility ranged from 1.20%-8.30% and 8.63%-9.22% respectively. CONCLUSIONS: Determination of specific HSP IgE with ELISA assay shows good specificity, sensitivity and reproducibility. It favours clinical practice due to its lower cost.

Allergens↗