Biomedical subjects

Rong Huang

Publications and source records attributed to Rong Huang.

34 records · Page 2Linked to original sources

PubMed2005

A human protein complex homologous to the Drosophila MSL complex is responsible for the majority of histone H4 acetylation at lysine 16.

We describe a stable, multisubunit human histone acetyltransferase complex (hMSL) that contains homologs of the Drosophila dosage compensation proteins MOF, MSL1, MSL2, and MSL3. This complex shows strong specificity for histone H4 lysine 16 in chromatin in vitro, and RNA interference-mediated knockdown experiments reveal that it is responsible for the majority of H4 acetylation at lysine 16 in the cell. We also find that hMOF is a component of additional complexes, forming associations with host cell factor 1 and a protein distantly related to MSL1 (hMSL1v1). We find two versions of hMSL3 in the hMSL complex that differ by the presence of the chromodomain. Lastly, we find that reduction in the levels of hMSLs and acetylation of H4 at lysine 16 are correlated with reduced transcription of some genes and with a G(2)/M cell cycle arrest. This is of particular interest given the recent correlation of global loss of acetylation of lysine 16 in histone H4 with tumorigenesis.

Acetylation↗

PubMed2005

The role of proxy information in missing data analysis.

This article investigates the role of proxy data in dealing with the common problem of missing data in clinical trials using repeated measures designs. In an effort to avoid the missing data situation, some proxy information can be gathered. The question is how to treat proxy information, that is, is it always better to utilize proxy information when there are missing data? A model for repeated measures data with missing values is considered and a strategy for utilizing proxy information is developed. Then, simulations are used to compare the power of a test using proxy to simply utilizing all available data. It is concluded that using proxy information can be a useful alternative when such information is available. The implications for various clinical designs are also considered and a data collection strategy for efficiently estimating parameters is suggested.

Canada↗

PubMed2005

[Study on flavonoids from Hedyotis diffusa Willd].

Five flavonoids were isolated from Hedyotis diffusa Willd. Their structures were elucidated as kaempferol (I), kaempferol 3-O-beta-D-glucopyranoside (II), kaempferol 3-O-(6"-O--L-rhamnosyl)-beta-D-glucopyranoside (III), quercetin 3-O-beta-D-glucopyranoside (IV) and quercetin 3-O-(2"-O-beta-D-glucopyranosyl)-beta-D-glucopyranoside (V) by spectroscopic analysis. Compounds I - III and V were originally isolated from H. diffusa.

Flavonoids↗

PubMed2005

[The effects of overnight sleep deprivation on cardiovascular autonomic modulation].

OBJECTIVE: This study aimed to delineate cardiovascular autonomic modulation associated with overnight total sleep deprivation (TSD) in humans. METHODS: Cardiovascular autonomic modulation during overnight total sleep deprivation was assessed in 18 normal male subjects [age: (26.2 +/- 4.2) years, BMI (23.9 +/- 1.7) kg/m(2)]. ECG and continuous blood pressure from radial artery tonometry were obtained in seated position before TSD (baseline) and after overnight TSD. Spectral analysis of heart rate variability (HRV) and BP variability (BPV) were computed for cardiac parasympathetic modulation (high frequency power, HF); sympathetic modulation (low frequency power, LF), sympatho-vagal balance (LF/HF power of R-R variability, LF/HF) and BPV sympathetic modulation (low frequency power, BPV LF) in normalized (N) units [(total power of the components)/(total power-very low frequency power) x 100]. RESULTS: No significant changes were found in BP and heart rate. HRV LF was increased significantly from baseline (59.4 +/- 15.7)% to overnight SD (67.0 +/- 13.9)%. HRV LF/HF was increased significantly from baseline (2.7 +/- 1.7) to overnight SD (3.8 +/- 2.3), HRV HFN was decreased from baseline (29.0 +/- 11.6)% to overnight SD (22.8 +/- 10.4)%, BPV LF was significantly increased from baseline (63.2 +/- 16.5)% to overnight SD (72.4 +/- 13.2)%. CONCLUSION: Acute SD was associated with increased sympathetic and decreased parasympathetic cardiovascular modulation.

Adolescent↗

PubMed2005

A new biflavonoid from Aristolochia contorta.

From the fruits of Aristolochia contorta Bge, beside the known aristolochic acids IVa and VII, aristolactam-N-beta-D-glucopyanoside, aristoloctam Ia N-beta-D-glucopyanoside, pinitol and daucosterol, a new biflavonoid was isolated. Its structure was determined as (+/-)-2"R,3"R-dihydro-3"-hydroxyamentoflavone (1) by means of spectral methods including 1D-, 2D-NMR and HR-ESIMS and the known compounds were identified on the basis of comparing their NMR data with those of the corresponding compounds in the literature.

Aristolochia↗

PubMed2004

Nature of vibrational coupling in helical peptides: an isotopic labeling study.

Infrared (IR) and vibrational circular dichroism (VCD) spectra were measured for a series of isotopically ((13)C on two or more amide Cdouble bond]O) labeled, 25 residue, alpha-helical peptides of the sequence Ac-(AAAAK)(4)AAAAY-NH(2) that were also studied in the previous paper. Theoretical IR and VCD simulations were performed for correspondingly isotopically labeled Ac-A(24)-NHCH(3) constrained to an alpha-helical conformation by use of property tensor transfer from density functional theory (DFT) calculations on Ac-A(10)-NHCH(3). The simulations predicted and experiments confirmed that the vibrational coupling constants between i, i + 1 and i, i + 2 residues differ in sign, thus leading to a reversal of the (13)C VCD pattern and explaining the large shift in the (13)C amide I frequency as reported in the previous paper. The sign of the coupling constant remained consistent for larger label separation (with the exception of i, i + 4) and for more labels with uniform separation. Such effects confirm that the isotopically labeled group vibrations are essentially only coupled to each other and are effectively uncoupled from those of the unlabeled groups. This development confirms the utility of isotopic labels for site-specific structural studies with vibrational spectra. Observed spectral effects cannot be explained by considering only transition dipole coupling (TDC) between amide oscillators, particularly for smaller label separations, but the TDC and ab initio predicted couplings roughly converge at large separation.

Alanine↗

PubMed2004

The complete chirospectroscopic signature of the peptide 3(10)-helix in aqueous solution.

We synthesized by solution methods a water-soluble, terminally blocked heptapeptide based on five markedly helicogenic, C(alpha)-tetrasubstituted alpha-amino acids C(alpha)-methyl-L-norvalines and two strongly hydrophilic 2-amino-3-[1-(1,4,7-triazacyclononane)]-L-propanoic acid residues at positions 2 and 5. A Fourier transform infrared absorption and NMR analysis in deuterated chloroform and aqueous solutions of the heptapeptide and two side-chain protected synthetic precursors confirmed our working hypothesis that all oligomers are folded in the 3(10)-helical conformation. Based on these findings, we exploited this heptapeptide as a chiral reference compound for detailed electronic CD, vibrational CD, and Raman optical activity characterizations of the 3(10)-helix in aqueous solution.

Circular Dichroism↗

PubMed2004

Masker-first advantage for cues in informational masking.

The detectability of a pure-tone signal may be reduced by adding a small number of randomly drawn masker tones remote from the signal frequency, an effect attributed to informational masking. A pretrial cue consisting of either the upcoming signal or masker releases informational masking, but a pretrial cue of the signal-plus-masker stimulus does not. In these experiments the relative potency of pre- and posttrial cues in releasing informational masking was examined. In separate conditions the masker-alone and signal-plus-masker stimuli were cues. The results indicated a masker-first advantage, i.e., sensitivity was superior when a masker cue preceded a yes/no trial interval compared to (a) when a signal-plus-masker preceded the trial, and (b) when either cue type followed the yes/no trial interval. A masker-first advantage was also obtained when the results from a two-interval forced-choice same/different task were examined. In contrast, a masker-first advantage was not obtained when the frequency of the signal to be detected was random. For detection tasks using random multi-tone maskers there may be differences in processing efficiency depending on the order in which stimuli are presented. The "masker-first advantage" may depend, in part, on observers maintaining their attention at the signal frequency.

Acoustic Stimulation↗

PubMed2004

[Effects of nasal continuous positive airway pressure on serum leptin concentration and the metabolic parameters in obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To evaluate the effects of nasal continuous positive airway pressure (nCPAP) on serum leptin concentration and the metabolic parameters in patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). METHODS: Serum leptin levels and true insulin (TI) levels were measured before and after one night nCPAP therapy in 18 patients. Eight patients received regular nCPAP treatment and had no change of body weight (BMI change < or = 1.5 kg/m2 from baseline) were recruited to the reassessment study 7.5 months after therapy. RESULTS: After one night use of nCPAP, there was a significant decrease in serum leptin [(8.47 +/- 0.62) microg/L vs (7.32 +/- 0.64) microg/L, P = 0.022] without change in other parameters. After 7.5 months of nCPAP treatment, serum leptin levels continued to decrease significantly without changes in BMI [(8.35 +/- 0.83) microg/L vs (6.05 +/- 0.78) microg/L; P = 0.036), and fast blood glucose (FBG) and true insulin (TI) also decreased significantly (P = 0.036) in OSAHS patients. However, triglyceral (TG) and cholesterol (Chol) maintained the pretreatment level (P > 0.05). CONCLUSIONS: OSAHS may have significant effects on the serum leptin levels and the correction of sleep disordered breathing by nCPAP can reduce the serum leptin levels. Decrease of leptin was independent of BMI change. The glucose metabolic disturbance and insulin resistance in OSAHS were improved after 7.5 months of nCPAP treatment.

Adult↗

PubMed2004

[Clinical analysis of lymphangioleiomyomatosis].

OBJECTIVE: To improve the diagnosis and treatment of lymphangioleiomyomatosis (LAM). METHODS: The clinical data of four cases of lymphangioleiomyomatosis diagnosed in our hospital were analyzed and corresponding literature was reviewed. RESULTS: Lymphangioleiomyomatosis, a rare disorder of unknown cause that occured almost exclusively in women of child bearing ages, was characterized microscopically by atypical smooth muscle proliferation. It could occur as a sporadic diseases or as a part of tuberous sclerosis complex (TSC). LAM was associated with progressive dyspnea, recurrent spontaneous pneumothoraces, chylous effusions, and hamartomas. CONCLUSION: Clinicians should be familiar with the characteristics of LAM so that diagnosis and treatment can be made earlier to improve the prognosis.

Adolescent↗

PubMed2003

Results of definitive irradiation in a series of 305 epidermoid carcinomas of the anal canal.

PURPOSE: To evaluate our data concerning the prognostic factors for locoregional control, survival, late complications, and sphincter conservation in a series of epidermoid cancers of the anal canal without clinical evidence of metastasis. METHODS AND MATERIALS: Between June 1972 and January 1997, 305 patients were treated with curative-intent radiotherapy (RT). The T stage according to the 1987 International Union Against Cancer classification was T1 in 26, T2 in 141, T3 in 104, and T4 in 34. Forty-nine patients had nodal involvement at presentation. The pretreatment anal function score, according to our in-house system, was 0 for 22 patients, 1 for 182, 2 for 74, 3 for 7, and 4 for 11 patients; for 9 patients, scores were unavailable. The treatment started with external beam radiotherapy (EBRT) in 303 patients (median dose 45 Gy). After a rest period of 4-6 weeks, a boost of 20 Gy was delivered by EBRT in 279 patients and by interstitial (192)Ir brachytherapy in 17 patients. Seven patients received only one course of EBRT (mean dose 49.5 Gy), and 2 patients were treated with interstitial (192)Ir brachytherapy alone (55 Gy and 60 Gy). Concomitant chemotherapy (5-fluorouracil and either mitomycin C or cisplatin) was delivered to 19 patients. The mean follow-up was 103 months (median 84). RESULTS: At the end of RT, the local tumor clinical complete response rate was 96% for T1, 87% for T2, 79% for T3, and 44% for T4. Of the 61 locally progressive tumors, 27 (44%) were salvaged with abdominoperineal resection. The rate of local tumor relapse was 12%. Among 37 local tumor relapses, 20 (54%) were salvaged with abdominoperineal resection and one with interstitial (192)Ir brachytherapy. The overall local control rate (with or without salvage local therapy) was 84%. The local control rate with good anal function (score 0 or 1) was 56.5%. Of 181 available patients with their anus preserved, 94% had good anal function. For a subgroup of 15 patients with a tumor length of <2 cm and without nodal involvement, the clinical complete response rate after RT completion was 100%, the local control rate with or without local salvage treatment was 100%, and among 13 available patients with their anus preserved, the anal function score was good in 12 patients (92%). The 10-year disease-free survival rate was 74%. After multivariate analysis, three independent predictive factors significantly influenced disease-free survival: the interval between the two courses of RT (>38 days vs. < or =38 days, p = 0.0025), pretreatment anal function score (0 vs. 1 vs. 2 vs. 3 vs. 4, p = 4.4.10(-6)), and clinical complete response after RT completion (no complete response vs. complete response, p = 2.5.10(-14)). CONCLUSION: We confirm the excellent results with RT in T1 and T2 lesions. However, to improve survival without colostomy with good anal sphincter function, chemoradiotherapy should be preferred for tumors > or =2 cm in length and for locally advanced tumors.

Adult↗

PubMed2003

Direct voltammetry and electrochemical catalysis with horseradish peroxidase in polyacrylamide hydrogel films.

This paper reports the direct voltammetry of horseradish peroxidase (HRP) incorporated in amphiphilic polyacrylamide (PAM) films modified on pyrolytic graphite (PG) electrodes. Cyclic voltammetry of HRP-PAM films showed a pair of well-defined, nearly reversible peaks at approximately -0.33 V vs. SCE in pH 7.0 buffers, characteristic of HRP heme Fe(III)/Fe(II) redox couple. The PAM films in solution contained large amounts of water and formed a hydrogel, and provided a favorable microenvironment for HRP and facilitated its direct electron transfer with underlying PG electrodes. The apparent heterogeneous electron transfer rate constant (k(s)) and formal potential (E*') were estimated by fitting the data of square wave voltammetry (SWV) with the non-linear regression analysis. UV-vis absorption spectra demonstrated that HRP in PAM films retained its secondary structure similar to its native state. The embedded HRP in PAM films showed the electrocatalytic activity to various substrates such as nitrite, oxygen and hydrogen peroxide. The possible mechanism of catalytic reaction of H(2)O(2) with HRP-PAM films was proposed.

Acrylic Resins↗

PubMed2003

[Influence of cervical curvature change on the nerve root and vertebral artery of patients with cervical spondylosis and clinical observation of manipulation treatment].

OBJECTIVE: To observe the influence of the change of cervical curvature on the nerve root and the vertebral artery of the patients with cervical spondylosis and the curative effect of therapeutic manipulations. METHODS: Sixty cases of cervical spondylosis with the change of cervical curvature, 60 cases of cervical spondylosis without the change of cervical curvature and 60 normal people were chosen. They were clinically observed and the cervical spondylosis was treated by manipulations and the data was processed according to the principle of statistics. RESULTS: The change of cervical curvature affected the nerve root and the vertebral artery and therapeutic manipulations produced a satisfactory curative effect. CONCLUSION: Cervical spondylosis with change of cervical curvature has special characteristics in the etiology, course and state of the disease. The change of cervical curvature produces an effect on the nerve root and the vertebral artery. Selected therapeutic manipulations produce a better curative effect.

Adult↗

PubMed2003

[An investigation of the relationship between Lepr gene Gln223Arg polymorphism and obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To investigate the relationship between leptin receptor (Lepr) gene Gln223Arg polymorphism and obstructive sleep apnea hypopnea syndrome (OSAHS). METHODS: The genotypes of Gln223Arg polymorphism in Lepr gene were determined by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) assay in 181 unrelated subjects of North region "Han" population (including 78 non-OSAHS subjects and 103 OSAHS subjects). RESULTS: The OSAHS patients with GG genotype had significantly larger neck circumference (NC) than did OSAHS patients with (GA + AA) genotype (P = 0.031); The study revealed no difference in genotype of Gln223Arg polymorphism between OSAHS group and non-OSAHS group (P = 0.676); There was also no significant difference in body mass index (BMI), waist hip rate (WHR), blood pressure (Bp), leptin (Lep), true insulin (TI), fast blood glucose (FBG), triglyceral (TG), cholesterol (Chol) and polysomnography (PSG) between GG and (GA + AA) genotype of OSAHS patients (P > 0.05). CONCLUSIONS: Lepr gene Gln223Arg polymorphism may be involved in the regulation of the neck regional fat distribution in OSAHS patients. It is unlikely that Lepr gene Gln223Arg polymorphism may contribute to the pathogenesis of OSAHS.

Adult↗

PubMed2003

[Protective effect and mechanism of pretreatment with curcumin on infectious brain edema in rats].

UNLABELLED: Curcumin is a natural compound extracted from the spice tumeric, possessing both anti-inflammatory antioxidant, and anti-carcinogenic effect, is a potent stimulator of the stress-induced expression of heat shock protein 70 kd (HSP70). OBJECTIVES: To study the protective effect of pretreatment with curcumin against infectious brain edema in rats, and investigate its mechanism by assessing the free radical, cytokine and HSP70 expression of the brain. METHODS: An animal model of infectious brain edema induced by injecting pertussis bacilli (PB) through carotid artery was used. SD rats were randomly divided into five groups: (1) Normal control group (NS group, n = 9); (2) Infectious brain edema group (PB group, n = 12); (3) DMSO control group (DMSO group, n = 9); (4) HS pretreatment group (HS group, n = 9); (5) Curcumin pretreatment group (CUR group, n = 13). The water content (WC), Na(+) and K(+) content in brain tissue were measured. The content of malondialdehyde (MDA) and super oxide dismitase (SOD) were assessed by chemical colorimetry. The levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1beta) were detected by ELISA. The HSP70 expression was examined by Western blot analysis. RESULTS: (1) The WC and Na(+), MDA, TNF-alpha and IL-1beta were increased in PB group compared with NS group (P < 0.01); they were decreased in HS and CUR groups compared with PB group (P < 0.01 or P < 0.05). (2) The content of SOD was decreased in PB group than in NS group (P < 0.05), and was increased in HS and CUR group Compared with PB group, (P < 0.05). (3) Western blot analysis showed that the band density areas of HS, CUR and PB groups were higher than those in NS and DMSO groups, especially in CUR group (P < 0.01). CONCLUSION: Pretreatment with curcumin showed a protective effect against infectious brain edema in rats. The effect might be associated with antioxidant, inhibition of the activity of cytokines and inducing expression of HSP70 by curcumin.

Animals↗

PubMed2000

Immunohistochemical study on p53, H-rasp21, c-erbB-2 protein and PCNA expression in HCC tissues of Han and minority ethnic patients.

AIM:To find out the difference of human primary liver carcinogenesis between Han and minority ethnic patients in Xinjiang.METHODS:Expression of p53, c-erbB-2, H-rasp21 protein and proliferating cell nuclear antigen (PCNA) in tumor tissues of 50 patients (Han 38, minority 12) with primary hepatic carcinoma was detected by immunohistochemistry (LSAB).RESULTS:The positive frequency of p53, c-erbB-2, H-rasp21 and PCNA expression was 46.0% (23/50), 70.0% (35/50), 68.0% (34/50) and 82.0% (41/50) in tumor tissues; 4.0% (2/50), 22.0% (11/50), 64.0% (32/50) and 52.0% (26/50) in peritumors respectively and a significant difference, except for H-rasp21, of oncogene alteration was found (P < 0.05) between tumor and non-tumorous tissues. Combined the three oncogenes alteration, 26% (13/50) tumor tissues had positive immunoreactivity, but in peritumor and normal livers it was negative. The positive rate of p53, c-erbB-2 and H-rasp21 protein expression was 39.5% (15/38), 60.5% (23/38) and 39.5% (15/38) in tumors of Han patients; 66.7% (8/12), 100% (12/12) and 75.0% (9/12) in minorities respectively, with statistical difference (P<0.05).CONCLUSION:Overexpression of p53,c-erbB-2 and H-rasp21 in human primary liver carcinoma is an important biomarker of genetic alteration. The different frequency of these oncogenetic changes may reflect some environmental or/and ethnic hereditary factors affecting the liver carcinogenesis. The special life style of Han, Uygur, Kazak and Mongolia nationalities in Xinjiang may also be related to the etiopathogenesis of this disease.

Journal Article↗