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Rong Chen

Publications and source records attributed to Rong Chen.

At least 55 records · Page 3Linked to original sources
PubMed2005

Graphical-Model-based Morphometric Analysis.

We propose a novel method for voxel-based morphometry (VBM), which we call Graphical-Model-based Morphometric Analysis (GAMMA), to identify morphological abnormalities automatically, and to find complex probabilistic associations among voxels in magnetic-resonance images and clinical variables. GAMMA is a fully automatic, nonparametric morphometric-analysis algorithm, with high sensitivity and specificity. It uses a Bayesian network to represent the associations among voxels and the function variable, and uses a contextual-clustering method based on a Markov random field to find clusters in which all voxels have similar associations with the function variable. We use loopy belief propagation to infer the unobserved label field and belief map. As opposed to voxel-based morphometric methods based on general linear models, GAMMA is capable of identifying nonlinear associations among the function variable and voxels. Compared with our previous approach, a Bayesian morphometry algorithm, GAMMA has greater sensitivity, specificity, and computational efficiency.

Algorithms↗
PubMed2005

A triple mutation in the second transmembrane domain of mouse dopamine transporter markedly decreases sensitivity to cocaine and methylphenidate.

Previously, we reported that Phe105 in transmembrane domain 2 of the mouse dopamine transporter (DAT) is crucial for high-affinity cocaine binding. In the current study, we investigated whether other residues surrounding Phe105 also affect the potency of cocaine inhibition. After three rounds of sequential random mutagenesis at these residues, we found a triple mutant (L104V, F105C and A109V) of mouse DAT that retained over 50% uptake activity and was 69-fold less sensitive to cocaine inhibition when compared with the wild-type mouse DAT. The triple mutation also resulted in a 47-fold decrease in sensitivity to methylphenidate inhibition, suggesting that the binding sites for cocaine and methylphenidate may overlap. In contrast, the inhibition of dopamine uptake by amphetamine or methamphetamine was not significantly changed by the mutations, suggesting that the binding sites for the amphetamines differ from those for cocaine and methylphenidate. Such functional but cocaine-insensitive DAT mutants can be used to generate a knock-in mouse line to study the role of DAT in cocaine addiction.

Amino Acid Substitution↗
PubMed2005

[Investigation on sleep status of college and high school students].

OBJECTIVE: To investigate the sleep status of college and high schools students. METHODS: Pittsburgh sleep quality index (PSQI) and self-manufactured questionnaires about siesta habits were used as tools. Three groups of students from medical college (MC), senior high school (SS) and junior high school (JS) were surveyed. RESULTS: In the group MC, SS and JS, the occurrence rates of sleep disorders were 27%, 62% and 54%, respectively, and in which the appearance rates of insomnia were 17%, 19% and 19%, longing for sleep were 10%, 43% and 35% respectively. And there were no significant difference between schoolboy and schoolgirl. The occurrence rates of slack breathing were different (5/155, 1/154) significantly between group SS and JS. The distinct differences also were found in group JS and MC, in which students felt hot (10/155, 1/122) and in all the three groups, in which students felt sleepy (55/155, 62/154, 13/122) whereas the difference of sleepy between group SS and JS was comparatively distinct (55/155, 62/154). Significant differences were also found between group JS and SS, MC in average sleep time of (7.65 +/- 0.87) hours, (7.16 +/- 0.83) hours, and (7.10 +/- 0.57) hours. The time of falling asleep (median 15 min, 10 min, 20 min) and siesta habit (8/155, 19/154, 75/122) among group MC and SS, JS were different respectively and markedly, whereas siesta habit differences between group SS and JS were comparatively distinct (8/155, 19/154). CONCLUSION: Students in high school showed higher rate of longing for sleep, and this implicated they fall short of sleep time greatly and siesta could improve their sleepy signs.

Adolescent↗
PubMed2005

[Examination expression of CD3 and CD69 in nasal polyps].

OBJECTIVE: To investigate the infiltration of T lymphocytes with CD3 expression as surface marker and the activation of T lymphocytes with CD69 expression as activation marker. METHODS: Nasal polyp tissue samples and peripheral blood were obtained from 21 patients. The normal inferior turbinate mucosa and peripheral blood were obtained as comparison. Flow cytometry was adopted to detect the expression of CD3 and CD69 of T lymphocytes. RESULTS: Nasal polyp tissue consisted of abundant T lymphocytes. Activation marker CD69 was expressed in T lymphocytes of nasal polyps (36.96 +/- 2.50)% and peripheral blood (4.66 +/- 0.18)% from the same patient. The expression rates of CD69 after a short-term stimulation (5 h) in response to PDB were (59.88 +/- 2.59)% and (92.76 +/- 0.55)% respectively. While T lymphocytes was rarely detected in normal inferior turbinate and the expression of CD69 was low in peripheral blood from normal human but almost all T lymphocytes were activated after stimulation. CONCLUSIONS: There were generous of T lymphocytes infiltrating in nasal polyps. The expression of CD69 in T lymphocytes was abnormally high, which indicated that T lymphocytes infiltrating in nasal polyps were in activated state immunologically.

Adolescent↗
PubMed2005

[Analysis of 21 cases of epithelial ovarian malignancies in women aged below 30 years].

OBJECTIVE: To study the presentation, histology type, stage of disease, treatment and outcome of epithelial ovarian malignancies in young women less than 30 years old. METHOD: A total of 21 cases of epithelial ovarian malignancies in young women less than 30 years old between Jan 1986 and Mar 2002 were analyzed retrospectively. RESULTS: The median age at the time of diagnosis was 24 years (range 16-29 years). All carcinomas occurred after menarche. The most common presenting symptoms were abdominal pain (50%), followed by tympanites (25%) and dysmenorrhea (19%), and the initial diagnosis was usually made based on physical examination, ultrasonography and serum CA(125). The mean maximal tumor diameter was 17.6 cm. Ten (67%) patients had stage I disease (5 Ia, 5 Ic), and 5 (33%) had stage III disease at the time of diagnosis; 43% were mucinous tumors, and 29% serous ones. Most tumors were well-differentiated ones classified as grade 1, 73%, others were grade 2, 13%, and grade 3, 13%. Optimal cytoreduction was achieved in 93% (14/15) of patients in primary treatment and 83% (5/6) in recurrence treatment. Eight patients were treated with conservative surgery, and 18 patients with chemotherapy, of which 7 patients had more than six courses of chemotherapy. The median follow-up was 50 months (range, 2-192 months). Six patients died in this series, 2 were alive with tumor, 11 alive free of tumor, and two were lost in follow-up. The 3-year and 5-year survival rate was 89%, and 76%, respectively. CONCLUSION: Young patients with epithelial ovarian carcinoma appear to have favorable stage and histologic grade and good survival.

Adolescent↗
PubMed2005

Cultivation and characters of aerobic granules for pentachlorophenol (PCP) degradation under microaerobic condition.

Cultivation of aerobic granular sludge for pentachlorophenol (PCP) degradation under microaerobic condition (DO concentration was controlled at 0.2-0.7 mg/L) was studied in this paper. Anaerobic granules were selected as inoculum. The changes of appearance were observed and the variations of SVI, VSS/TSS, PN/PS and the size of sludge were measured during cultivating. The capabilities for degradation of PCP, AOX and COD(Cr) were also studied. Observations on mature granules were carried out by scanning electron microscope, and the results indicated bacillus was dominant on the surface of granules while in the inner of granules both bacillus and coccus were the dominant microorganisms. K, Na, Fe, Ca, Mg, Ni, Co, Mn, Cu and Zn were detected in the granules by element analysis.

Aerobiosis↗
PubMed2005

[Fourier transform infrared and near-infrared Raman spectra of human red blood cell].

The human red blood cell was studied by Fourier transform infrared and near-infrared Raman spectroscopy.The assignment of the characteristic groups of human red blood cell structure was basically confirmed. At the same time, the authors observed that the intensity of different Raman shift signal has different varying law when the power of laser is changing. Near-infrared laser Raman spectroscopy combined with infrared spectroscopy is an effective method to study the structure of human red blood cell.

Blood Grouping and Crossmatching↗
PubMed2005

[Effect of immune-enhanced enteral diet on postoperative immunological function in patients with colorectal cancer].

OBJECTIVE: To explore the influence of immune-enhanced enteral diet on postoperative metabolism and immunological function in colorectal tumor patient. METHODS: Seventy-two patients with colorectal cancer were enrolled in this study. Immune-enhanced enteral diet was administrated in 36 cases (study group), while regular enteral nutrition (EN) was given in 36 cases (control group). The immunological function, inflammatory function and nutrition index were evaluated before operation and on postoperative day 1 and day 8. RESULTS: Serum levels of glutamine, asparagines, CD4 (+), NK, IgG, IgM were higher in the study group than those in the control group. The levels of IL- 6, TNF-alpha in the study group were lower than those in the control group. The difference was statistically significant (P< 0.05). CONCLUSIONS: Immune-enhanced enteral diet can ameliorate the cell immunological and fluid immunological function in the patients with colorectal cancer after the procedures.

Adult↗
PubMed2005

[Establishing the norm of cognitive adaptive test/clinical linguistic and auditory milestone scale in the children from 4 to 36 months of age in Shanghai, China].

OBJECTIVE: To meet the need for instrument assessing the cognitive abilities of infants and young children as well as discriminating between global developmental delay and particular deficits in either language or problem-solving skills, we intended to introduce Cognitive Adaptive Test/Clinical Linguistic and Auditory Milestone Scale (CAT/CLAMS) into China. METHODS: CAT/CLAMS were administered to 1604 normative children aged 4-36 months (in 16 age groups, about 100 children per age group) in Shanghai during the period from December 2003 to June 2004. In the meantime, Gesell Developmental Diagnosis was applied for 100 of these children, respectively aged 4, 6, 12, 18 and 30 months (20 children per age group). Interclass correlation coefficients (ICC) were adopted to analyze data in terms of inter-rater reliability and re-test reliability of the scales of CAT/CLAMS. Cronbach alpha coefficients were calculated to assess the inter consistency of the scales. Pearson correlation coefficients(r) were adopted to analyze the concurrent validity of the scales. The normative percentile graphs of CAT/CLAMS in the children from 4 to 36 Months of age in Shanghai, China were adopted. RESULTS: Administrations of the CAT/CLAMS for each subject usually took 10-20 minutes. Individual scores (CLAMS, CAT, and CAT/CLAMS) increased with ages (Pearson correlation coefficients were 0.96, 0.98 and 0.98, respectively, P < 0.01 for all). ICCs (intraclass correlation coefficient) in terms of individual scores for the inter-rater reliability test and the re-test reliability test were respectively > or = 0.96 (P < 0.01) and > or = 0.95 (P < 0.01), all the Cronbach alpha coefficients were > or = 0.98; in 100 children of the 5 age groups, there was significantly positive correlation between CAT/CLAMS and Gesell Developmental Diagnosis in terms of language skill DQ and adaptive skill DQ, and Full Scale DQ (r = 0.517, 0.703, 0.613, respectively, P < 0.01 for all). Moreover, this significant positive correlation was observed in each of the 5 age groups (r = 0.455-0.827, P < 0.05). CONCLUSION: CAT/CLAMS is suitable for discriminating between global developmental delay and particular deficits in either language or problem-solving skills. It is a quick, reliable, and valid instrument, with refined and quantified results. It is a good tool for developmental surveillance and screening of infants and young children.

Child Development↗
PubMed2005

[CD34+ antigen expression relating to prognosis in acute myeloid leukemia].

To explore CD34(+) antigen expression in new diagnosed acute myeloid leukemia (AML) and analyze the prognosis for CD34(+) AML patients, the expression of antigen CD34 in 238 AML patients was detected by indirect immunofluorescence assay. The results showed that CD34 in 92 out of the 238 patients (38.7%) were positive, there was relationship between the CD34(+) expression and FAB subtypes (M(0), M(1)), and no CD34(+) expression was observed in M(3) subtypes. The complete remission rate of CD34(+) AML patients was 32%, which was lower than that of CD34(-) AML (61%). The lymphoid-associated antigen (CD7) was significantly increased in CD34(+) AML patients, compared with CD34(-) patients (P < 0.05). It is concluded that CD34(+) AML patients show poor prognosis and lower CR rate. The detection of CD34 expression is of some value in predicting prognosis in AML.

Adolescent↗
PubMed2005

[The mechanic retention of the casting post with keeper in magnetic retentor overdenture].

PURPOSE: To reduce the cost of the fabrication of the magnetic retentor,and meet the clinical requirements, nonprecious alloy such as Co-Cr alloy was used to fabricate the magnetic retentor in overdenture , instead of the precious alloy. METHODS: A mandibular canine was chosen for root canal preparation in vitro. Thirty two resin posts were made in the same root canal with self-curing resin. The 32 resin posts were randomly divided into 4 groups. Among them,2 groups were fabricated with soft Co-Cr alloy, gold alloy(55.6%Au) respectively in vitro. Another 2 groups were fabricated with Co-Cr alloy, and the surface of the root casting post with keeper were treated with gold deposit and gold coating technique. After that, test of dislodgment force was done and one-way ANOVA was performed with SAS 6.2 software package. RESULTS: The dislodgment force of the root casting posts with keeper which were fabricated with the Co-Cr, Ni-Cr, and gold alloy had significant difference(P<0.01). While after surface treatment by gold deposit and gold coating technique on root casting posts with keeper that were fabricated with Co-Cr and Ni-Cr alloy, there was no significant difference in dislodgment force, compared with that of gold alloy. CONCLUSIONS: After surface treatment of the root casting posts with keeper which were fabricated with the Co-Cr and Ni-Cr alloy, the same clinical retentive effect can be obtained as the one that was fabricated with gold alloy.

Chromium Alloys↗
PubMed2004

Importance of chirality and reduced flexibility of protein side chains: a study with square and tetrahedral lattice models.

Side chains of amino acid residues are the determining factor that distinguishes proteins from other unstable chain polymers. In simple models they are often represented implicitly (e.g., by spin states) or simplified as one atom. Here we study side chain effects using two-dimensional square lattice and three-dimensional tetrahedral lattice models, with explicitly constructed side chains formed by two atoms of different chirality and flexibility. We distinguish effects due to chirality and effects due to side chain flexibilities, since residues in proteins are L residues, and their side chains adopt different rotameric states. For short chains, we enumerate exhaustively all possible conformations. For long chains, we sample effectively rare events such as compact conformations and obtain complete pictures of ensemble properties of conformations of these models at all compactness region. This is made possible by using sequential Monte Carlo techniques based on chain growth method. Our results show that both chirality and reduced side chain flexibility lower the folding entropy significantly for globally compact conformations, suggesting that they are important properties of residues to ensure fast folding and stable native structure. This corresponds well with our finding that natural amino acid residues have reduced effective flexibility, as evidenced by statistical analysis of rotamer libraries and side chain rotatable bonds. We further develop a method calculating the exact side chain entropy for a given backbone structure. We show that simple rotamer counting underestimates side chain entropy significantly for both extended and near maximally compact conformations. We find that side chain entropy does not always correlate well with main chain packing. With explicit side chains, extended backbones do not have the largest side chain entropy. Among compact backbones with maximum side chain entropy, helical structures emerge as the dominating configurations. Our results suggest that side chain entropy may be an important factor contributing to the formation of alpha helices for compact conformations.

Computer Simulation↗
PubMed2004

Differential acquisition of food-reinforced disk pressing by CD-1, BALB/cJ and C57BL/6J mice.

Developments in the genetic manipulation of mice have intensified interest in the relation between genes, environment and learned behavior, which in turn has led to exploration of experimental procedures for assessing genetic influences on learning using methods such as response acquisition. The requirement for multiple experimental control groups in such genetic comparisons studies amplifies the need for reliable, instrument-directed, learning assessment paradigms. The purpose of the present experiment was to implement such a procedure in several successive phases, including pre-food basal rates of interaction with sensors in a chamber, food-hopper training, and a simple disk-baiting procedure that produced differentially food-reinforced disk pressing (FR1) and provided quantitative measures of learning in outbred (CD-1) and inbred (C57BL/6J, BALB/cJ) mice. Response acquisition performances were measured in terms of the number of correct food-producing responses (disk press to hopper entry in less than 5s). The three mouse types showed differences in several performance measures prior to response acquisition training. Pre-food basal performances did not predict subsequent rate of acquisition of the target response. On average, CD-1 mice met a criterion of 50 food-producing responses slightly, but not significantly, faster than BALB/cJ mice. The C57BL/6J mice took significantly longer to meet the learning criterion and had slower response rates, due to longer after-reinforcement pausing. Procedural differences (massed versus partial/distributed training) and reinforcement parameters (duration of access) may differentially affect different mouse types independently of genetic differences in response acquisition.

Animals↗
PubMed2004

Nitric oxide synthase inhibition accelerates the pressor response to low-dose angiotensin II, exacerbates target organ damage, and induces renin escape.

Because nitric oxide may attenuate both the pressor and cytotoxic effects of angiotensin II (Ang II), we investigated whether nitric oxide synthase (NOS) inhibition might accelerate the slow pressor effect of Ang II, and augment target organ damage. Using conscious, chronically catheterized rats, we previously observed that low-dose Ang II (10 ng/kg/min) rapidly increased mean arterial pressure (MAP) by approximately 25 mm Hg. The MAP then remained at this level for 2 to 4 days, and then increased again during the next 5 days by a further 25 mm Hg to a second plateau. In the present study, 7 days of N(omega)-nitro-l-arginine methyl ester (L-NAME; 10 microg/kg/min) alone increased MAP by 16 mm Hg. When Ang II was added to L-NAME, MAP increased as much as with Ang II alone, but then continued to increase until day 4, reaching a plateau as high as that reached only on day 9 of Ang II alone. In approximately half the rats infused with L-NAME + Ang II, plasma renin escaped from Ang II-induced suppression after day 4 of Ang II, and continued to increase for the duration of the study. On the first day that Ang II was added to L-NAME, urinary protein excretion and plasma cardiac troponin T increased, indicating early target organ damage. By the end of the study, all rats treated with L-NAME + Ang II developed tubulointerstitial and glomerular injuries, fibrosis of the renal and cardiac arteries, and cardiac interstitial fibrosis. Target organ damage was greater in rats that developed renin escape than in those in which plasma renin remained suppressed, but was minimal in rats infused with Ang II or L-NAME alone. Taken together, these findings suggest that endogenous NO normally attenuates the pressor response to low-dose Ang II for several days, and protects from Ang II-induced target organ damage. Under conditions of reduced NO bioavailability, which may result from endothelial insufficiency, relatively small changes in circulating Ang II levels may damage target organs. Moreover, renal damage leading to renin escape may initiate a vicious cycle of elevated Ang II production, leading to higher blood pressure and greater target organ damage.

Angiotensin II↗
PubMed2004

1-stage urethral reconstruction using colonic mucosa graft for the treatment of a long complex urethral stricture.

PURPOSE: We investigated the possibility of urethroplasty with a free graft of colonic mucosa for long, complex urethral strictures. We report our initial experience with colonic mucosa graft urethroplasty for such urethral strictures in 16 patients. MATERIALS AND METHODS: Between September 2000 and December 2002, 16 patients with a long, complex urethral stricture were treated with colonic mucosal graft urethroplasty. Patients had undergone an average of 2.5 previous unsuccessful repairs. Urethral reconstruction was done with a 10 to 17 cm (median 13) graft of colonic mucosa RESULTS: Patients were followed 6 to 33 months postoperatively. Meatal stenosis that developed in 1 patient 3 months postoperatively needed reoperation. The patient was voiding well with a urinary peak flow of 28.7 ml per second during 9-month followup after reoperation. Hyperplasia of the verumontanum was observed during urethroscopy and transurethral colliculectomy was performed in 1 patient more than 14 months postoperatively. Uroflowmetry showed a urinary peak flow of 46.5 ml per second postoperatively. The other patients were voiding well with a urinary peak flow of greater than 15 ml per second. Urethrogram revealed a patent urethra with an adequate lumen and no significant graft sacculation. CONCLUSIONS: This initial experience in 16 patients indicates that colonic mucosa graft urethroplasty is a feasible procedure for long, complex anterior urethral strictures. The technique may be considered for urethral reconstruction when more conventional procedures have failed.

Adolescent↗
PubMed2004

Inter- and intragenus structural variations in caliciviruses and their functional implications.

The family Caliciviridae is divided into four genera and consists of single-stranded RNA viruses with hosts ranging from humans to a wide variety of animals. Human caliciviruses are the major cause of outbreaks of acute nonbacterial gastroenteritis, whereas animal caliciviruses cause various host-dependent illnesses with a documented potential for zoonoses. To investigate inter- and intragenus structural variations and to provide a better understanding of the structural basis of host specificity and strain diversity, we performed structural studies of the recombinant capsid of Grimsby virus, the recombinant capsid of Parkville virus, and San Miguel sea lion virus serotype 4 (SMSV4), which are representative of the genera Norovirus (genogroup 2), Sapovirus, and Vesivirus, respectively. A comparative analysis of these structures was performed with that of the recombinant capsid of Norwalk virus, a prototype member of Norovirus genogroup 1. Although these capsids share a common architectural framework of 90 dimers of the capsid protein arranged on a T=3 icosahedral lattice with a modular domain organization of the subunit consisting of a shell (S) domain and a protrusion (P) domain, they exhibit distinct differences. The distally located P2 subdomain of P shows the most prominent differences both in shape and in size, in accordance with the observed sequence variability. Another major difference is in the relative orientation between the S and P domains, particularly between those of noroviruses and other caliciviruses. Despite being a human pathogen, the Parkville virus capsid shows more structural similarity to SMSV4, an animal calicivirus, suggesting a closer relationship between sapoviruses and animal caliciviruses. These comparative structural studies of caliciviruses provide a functional rationale for the unique modular domain organization of the capsid protein with an embedded flexibility reminiscent of an antibody structure. The highly conserved S domain functions to provide an icosahedral scaffold; the hypervariable P2 subdomain may function as a replaceable module to confer host specificity and strain diversity; and the P1 subdomain, located between S and P2, provides additional fine-tuning to position the P2 subdomain.

Amino Acid Sequence↗
PubMed2004

Laser-induced autofluorescence microscopy of normal and tumor human colonic tissue.

Laser-induced autofluorescence (LIAF) spectroscopy has been found to be a promising tool for early cancer diagnosis in various organs, but the reasons responsible for the spectral differences between normal and diseased tissue are still not well understood. In this study, a microspectrophotometer (MSP) system was used to identify the microscopic origins of tissue autofluorescence in the colon under the excitation of a helium-cadmium laser at 442 nm. Colonic tissue samples (normal: n=8, adenocarcinoma: n=10) were obtained from 12 patients with known or suspected malignancies of the colon. The intrinsic fluorescence spectra and images of fresh tissue sections prepared from normal and tumor colonic tissue were measured by the MSP system. Three distinct tissue layers of the colon were found for fluorescence, the mucosa, the submucosa and the muscularis propria, with submucosa being the most fluorescent. Differences in the spectral shape and intensity of the intrinsic fluorescence originating from different colonic layers indicate that fundamentally different fluorophores may be present in the respective tissue layers. There was no significant difference in the intrinsic fluorescence features of the submucosa between normal and tumor colonic tissue, but the fluorescence intensity of the submucosa in tumor tissue was significantly reduced due to the infiltration of tumor cells into the submucosa. The intrinsic fluorescence spectrum peaking at about 520 nm for tumor stroma appeared more evident than that of normal lamina propria. Limited areas of the lamina propria layer in some adenocarcinoma colon exhibited an emission band at about 635 nm, which was attributed to endogenous porphyrins in tumor. Autofluorescence microscopy revealed that differences in the clinically measured autofluorescence spectra between normal and tumor tissue were mainly due to thickening of the tumor mucosa resulting in a reduced submucosa fluorescence contribution, as well as the increased hemoglobin absorption in tumor tissue. Therefore, investigation of the microscopic origins of tissue autofluorescence and images can provide new insights into morphological structures and biochemical components of tissues, which are vital to improve the implementation of the LIAF technique for non-invasive in vivo tissue diagnostics.

Adenocarcinoma↗