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Biomedical subjects

Zhong Ren

Publications and source records attributed to Zhong Ren.

16 recordsLinked to original sources
PubMed2006

[Effects of asphyxia on endocochlear direct-current potential in guinea pig].

OBJECTIVE: To investigate the mechanism of auditory function disturbance due to asphyxiants. METHOD: Guinea pigs with nice auricle reflex were selected in the experiment. The changes of endocochlear direct-current potential (EP) were detected when apnea and after artificial respiration, using the stria vascularis method. RESULT: (1) The original EP of experimental group was (76.4+/-8.4) mV, and the original EP of control group was (80.8+/-8.4) mV, there was no significant difference between them. (2) During apnea, the EP of all the guinea pigs decreased precipitously after incubation period of 8 to 34 seconds. The decreasing rate of EP was positively correlated to the incubation period (P=0.008). (3) After 3 minutes of apnea, the mean minimum of EP was (-17.5+/-4.4) mV, which was positively correlated with decreasing rate and incubation period (P was 0.0002, 0.000 separately). (4) After artificial respiration, it needed the average time of (85.0+/-16.0) s to return original EP, and 7 cases got an overrun. CONCLUSION: The EP of all the guinea pigs decreased when apnea, which showed the abnormal living circumstance of acoustic hair cells. After 3 minutes of apnea, the EP of all the guinea pigs decreased to negative value, which demonstrated that the functions of acoustic hair cells had not lost within 3 minutes of apnea. After artificial respiration, all the guinea pigs' EP returned to original value, which indicated that the functions of the stria vascularis had not failed irreversibly.

Animals↗
PubMed2006

[Methylation status of uPA promoter in laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the relationship between methylation status of urokinase type plasminogen activator (uPA) promoter and invasion/metastasis of laryngeal squamous cell carcinoma (LSCC). METHOD: Using RT-PCR technique, specimens from 40 patients of LSCC were detected for their expression of the uPA gene. Meanwhile, methylation-specific PCR was used to detect methylation status of uPA promoter. RESULT: Positive expression rate of uPAmRNA in LSCC was 65.0% (26/40), and the rate of expression of uPAmRNA in LSCC with cervical lymph node metastasis was higher than that of in LSCC without cervical lymph node metastasis (P <0.05). Methylation of uPA promoter was observed in 8 (20.0%) of 40 cases of LSCC, and the rate of methylation of uPA promoter in LSCC with cervical lymph node metastasis was lower than that of in LSCC without cervical lymph node metastasis (P <0.01). The expression of uPAmRNA was not detected in methylated cancer tissues. CONCLUSION: Methylation leads to lose of the uPA gene expression in LSCC. Demethylation of uPA promoter may be correlated to cervical lymph node metastasis.

Aged↗
PubMed2005

Structural basis for an unexpected mode of SERM-mediated ER antagonism.

Tamoxifen is effective for the prevention and treatment of estrogen-dependent breast cancers, but is associated with an increased incidence of endometrial tumors. We report the crystal structure of the estrogen receptor alpha (ERalpha) ligand binding domain (LBD) bound to the structurally similar compound GW5638, which has therapeutic potential and does not stimulate the uterus. Like tamoxifen, GW5638 relocates the carboxy-terminal helix (H12) to the known coactivator-docking site in the ERalpha LBD. However, GW5638 repositions residues in H12 through specific contacts with the N terminus of this helix. In contrast to tamoxifen, the resulting increase in exposed hydrophobic surface of ERalpha LBD correlates with a significant destabilization of ERalpha in MCF-7 cells. Thus, the GW5638-ERalpha LBD structure reveals an unexpected mode of SERM-mediated ER antagonism, in which the stability of ERalpha is decreased through an altered position of H12. This dual mechanism of antagonism may explain why GW5638 can inhibit tamoxifen-resistant breast tumors.

Amino Acid Sequence↗
PubMed2005

[Expression of KAI1 gene in human laryngeal carcinoma and its clinical significance].

OBJECTIVE: To explore the mRNA expression of KAI1 gene in laryngeal squamous-cell carcinoma and its clinical significance. METHODS: Fresh laryngeal cancer samples taken from 40 laryngeal carcinoma cases and normal control laryngeal tissues from 9 subjects were examined with semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Moderate, low and negative expression rates of KAI1 gene mRNA in nine normal laryngeal tissues were 33.3% (3/9), 33.3% (3/9) and 33.3% (3/9), respectively. The high, moderate, low and negative expression rates of KAI1 mRNA in 25 laryngeal cancers without lymph node metastasis were 40.0% (10/25), 28.0% (7/25), 20.0% (5/25) and 12.0% (3/25), respectively. The moderate, low and negative expression rates of KAI1 mRNA in 15 laryngeal cancers with lymph node metastasis were 20.0% (3/15), 26.7% (4/15) and 53.3% (8/15), respectively. The KAI1 mRNA expression in the laryngeal cancers without lymph node metastasis was higher than that in normal laryngeal tissues (P < 0.05). The KAI1 mRNA expression in the laryngeal cancers with lymph node metastasis was lower than that in the laryngeal cancers without lymph node metastasis (P < 0.05). The high, moderate and low expression rates of KAI1 mRNA in 10 highly differentiated laryngeal cancers were 50.0% (5/10), 30.0% (3/10) and 20.0% (2/10), respectively. The high, moderate, low and negative expression rates of KAI1 mRNA in 12 low differentiation laryngeal cancers were 8.3% (1/12), 16.7% (2/12), 16.7% (2/12) and 58.3% (7/12), respectively. The differences of KAI1 mRNA expression between high and low differentiation laryngeal cancers were statistically significant (P < 0.05). CONCLUSION: The decrease of KAI1 mRNA expression may be related to lymph node metastasis and low differentiation of laryngeal squamous-cell carcinoma.

Adult↗
PubMed2005

[Early characters of recurred vocal cord cancers after laser cordectomy and treatment].

OBJECTIVE: To explore the characters of recurred vocal cord cancer in early phase after laser cordectomy and selection of the second treatment. METHOD: Five cases who had recurrence after laser cordectomy was selected and analyzed according to the scope of the tumor, operation type, recurrence time, site of recurrence. RESULT: One case's had the first recurrence two months after the first operation and was treated by laser once more, and the second recurrence happened three months after the second operation and no recurrence was found within the 4 years after the third operation-extended vertical hemilaryngectomy. Two cases had recurrence 3 months after the first operation and one case 6 months later. The three cases had extended vertical hemilaryngectomy for remedy and had no recurrence within 4 years. The last one had recurrence 1 year after operation, and received a total laryngectomy. The site of recurrence was the anterior commission in 4 cases and median part of vocal cord in one case. The 5 cases included 3 T1a and 2 T1b. The recurrence rate of T1a and T1b were 3.1% and 50.0% respectively. CONCLUSION: The recurrence time after laser cordectomy is often within half a year. The most common site of recurrence is anterior commission. Extended partial laryngectomy should be the first choice remedy. Strict selection of indication and skillful technique are the base of good efficacy.

Adult↗
PubMed2005

[Apoptosis and expression of apoptosis-related proteins in experimental different denervated guinea-pig facial muscle].

OBJECTIVE: To study apoptosis and expression of apoptosis-related proteins in experimental different denervated guinea-pig facial muscle. METHOD: An experimental model was established with guinea pigs by compressing the facial nerve 30 second (reinnervated group) and resecting the facial nerve (denervated group). TUNEL method and immunohistochemical technique (SABC) were applied to detect the apoptosis and expression of apoptosis-related proteins bcl-2 and bax from 1st to 8th week after operation. RESULT: Experimentally denervated facial muscle revealed consistently increase of DNA fragmentation, average from(34.4 +/- 4.6)% to (38.2 +/- 10.6)%, from 1st week to 8th week after operation; Reinnervated facial muscle showed a temporal increase of DNA fragmentation, and then the muscle fiber nuclei revealed decreased DNA fragmentation along with the function of facial nerve recovered, latterly normal, average from (32.0 +/- 8.03)% to (5.6 +/- 3.5)%, from 1st week to 8th week after operation. In denervated group, bcl-2 and bax were expressed strongly; in reinnervated group, bcl-2 expressed consistently, but bax disappeared latterly along with the function of facial nerve recovered. CONCLUSION: Expression of DNA fragmentation and apoptosis-related proteins in denervated muscle are general reaction to denervation. bcl-2 can prevent early apoptotic muscle fiber to survival until reinnervation. It is concluded that proteins control apoptosis may give information for possible therapeutic interventions to reduce the rate of muscle fiber death in denervated atrophy in absence of effective primary treatment.

Animals↗
PubMed2004

Protein kinetics: structures of intermediates and reaction mechanism from time-resolved x-ray data.

We determine the number of authentic reaction intermediates in the later stages of the photocycle of photoactive yellow protein at room temperature, their atomic structures, and a consistent set of chemical kinetic mechanisms, by analysis of a set of time-dependent difference electron density maps spanning the time range from 5 micros to 100 ms. The successful fit of exponentials to right singular vectors derived from a singular value decomposition of the difference maps demonstrates that a chemical kinetic mechanism holds and that structurally distinct intermediates exist. We identify two time-independent difference maps, from which we refine the structures of the corresponding intermediates. We thus demonstrate how structures associated with intermediate states can be extracted from the experimental, time-dependent crystallographic data. Stoichiometric and structural constraints allow the exclusion of one kinetic mechanism proposed for the photocycle but retain other plausible candidate kinetic mechanisms.

Bacterial Proteins↗
PubMed2004

[Detection of mutation in exon 5 and exon 8 of PTEN in laryngeal squamous cell carcinoma].

OBJECTIVE: To detect mutations of exon 5 and exon 8 of phosphatase and tensin homology deleted on chromosome10/mutated in multiple advanced cancer1/TGF-beta regulated and epithelial cell-enriched phosphatase (PTEN/MMAC1/TEP1 for short PTEN) gene in laryngeal squamous cell carcinoma (LSCC) and analyze the relationship between the mutation and LSCC. METHODS: Fresh tumor samples from 40 LSCC patients were examined using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct DNA sequencing. RESULTS: The mutation of exon 5 and exon 8 occurred in supra-glottic laryngeal carcinoma and no mutation in the glottic laryngeal carcinoma was found. There were 6 cases of mutation for exon 5, and the mutation rate was 15%. In 2 cases, 1 base pair insertion TT-->TAT in codon 85, while in other two cases, 1 base pair deletion GCA-->GC in codon 86, and the two type mutation may result in frame shift mutation. One case had the above two type mutation simultaneously, which may result in missense mutation; 1 case had 1 base pair insertion TT-->TAT in 85 codon and 1 base pair deletion GCA-->GA, which may result in nonsense mutation. The pathology of 3/6 (50%) cases was low differentiation, and the others (3/6, 50%) were middle differentiation. Five cases had lymphatic metastasis, and the rate of which was 83.3%; the other one had no lymphatic metastasis, and the rate of which was 16.7%. There was only 1 case mutation for exon 8, and the mutation rate was 2.5%. One base pair deletion AAA-->AA in 276 codon as well as 1 base pair insertion CT-->CCT between the 336 codon and 337 codon may result in frame shift mutation. The pathology of the case was low differentiation. CONCLUSION: The codon 85,86 of PTEN gene in exon 5 may be "hot spots" in LSCC and the mutation of PTEN gene may be related with the lymphatic metastasis and middle or low differentiation.

Adult↗
PubMed2004

[Distribution and prognostic significance of microvessel density in supraglottic laryngeal squamous cell carcinomas].

OBJECTIVE: To study the distribution and prognostic significance of microvessel density (MVD) in supraglottic laryngeal squamous cell carcinomas (SGLSCC). METHOD: The patients of 59 primary SGLSCC received surgical treatment and 19 vocal cord polyps (VCP) were studied with CD31 immunohistochemical staining using Two Steps System Kits. RESULT: There were many microvessels in the stroma of SGLSCC compared with the connective-tissue under epithelium of VCP. Kendall's ranked correlation analysis indicated that only MVD and nodal status had significant correlation (P<0.01) in all clinicopathological parameters. Both between N0 and N+ and between SGLSCC and VCP MVD were significantly different (P<0.01) by independent-samples t test. Kaplan-Meier survival analysis showed significant relationship existed in MVD and cumulative survival rate of SGLSCC patients (P<0.01). CONCLUSION: This study further proves that angiogenesis plays important roles in tumorigenesis, invasiveness and metastasis. MVD could predict the lymph node metastasis and are significantly associated with the prognosis of SGLSCC patients.

Adult↗
PubMed2004

[Histopathology study of supraglottic carcinoma with different vocal cord movement].

OBJECTIVE: To explore the histopathology characteristics of supraglottic carcinoma with different vocal cord movement, and to find the theory basis for partial laryngectomy. METHOD: Eighty-four cases of supraglottic laryngeal carcinoma specimen were imbedded in collodion, and then make whole-organ serial section for HE staining, observing under light microscope. RESULT: For the vocal cord fixation, the rate of invasion to arytenoids, to infra-paraglottic space and to both arytenoids and infra-paraglottic space was 46.2%, 15.4%, and 38.5%, respectively; For the vocal cord limitation, the rate of invasion to arytenoids, to infra-paraglottic space and to both arytenoids and infra-paraglottic space was 46.7%, 6.7%, and 13.3%, respectively; For the vocal cord with good movement, no cases occurred for the invasion to the infra-paraglottic space or arytenoids. The difference was significant between them (P<0.05). There was close relationship between the tumor invasion to infra-paraglottic space with to the ventricle of larynx: for the vocal cord limitation and fixation, the ratio of the tumor invading the infra-paraglottic space to the ventricle of larynx is 40.0% and 73.7%, respectively, the difference was significant between them (P<0.05). CONCLUSION: The invasion of supra-glottic carcinoma to the arytenoids or infra-paraglottic space is the main cause of the vocal cord limitation and fixation. We can do the operation of partial laryngectomy more precisely by observing the movement of the vocal cord and the invasion to laryngeal ventricle.

Adult↗
PubMed2003

Automated crystallographic system for high-throughput protein structure determination.

High-throughput structural genomic efforts require software that is highly automated, distributive and requires minimal user intervention to determine protein structures. Preliminary experiments were set up to test whether automated scripts could utilize a minimum set of input parameters and produce a set of initial protein coordinates. From this starting point, a highly distributive system was developed that could determine macromolecular structures at a high throughput rate, warehouse and harvest the associated data. The system uses a web interface to obtain input data and display results. It utilizes a relational database to store the initial data needed to start the structure-determination process as well as generated data. A distributive program interface administers the crystallographic programs which determine protein structures. Using a test set of 19 protein targets, 79% were determined automatically.

Automation↗
PubMed2003

Application of singular value decomposition to the analysis of time-resolved macromolecular x-ray data.

Singular value decomposition (SVD) is a technique commonly used in the analysis of spectroscopic data that both acts as a noise filter and reduces the dimensionality of subsequent least-squares fits. To establish the applicability of SVD to crystallographic data, we applied SVD to calculated difference Fourier maps simulating those to be obtained in a time-resolved crystallographic study of photoactive yellow protein. The atomic structures of one dark state and three intermediates were used in qualitatively different kinetic mechanisms to generate time-dependent difference maps at specific time points. Random noise of varying levels in the difference structure factor amplitudes, different extents of reaction initiation, and different numbers of time points were all employed to simulate a range of realistic experimental conditions. Our results show that SVD allows for an unbiased differentiation between signal and noise; a small subset of singular values and vectors represents the signal well, reducing the random noise in the data. Due to this, phase information of the difference structure factors can be obtained. After identifying and fitting a kinetic mechanism, the time-independent structures of the intermediates could be recovered. This demonstrates that SVD will be a powerful tool in the analysis of experimental time-resolved crystallographic data.

Algorithms↗
PubMed2003

[The expression of extracellular matrix in squamous cell carcinoma of the larynx: an immunohistochemical study].

OBJECTIVE: To investigate the expression and the protective significance of extracellular matrix (ECM) in laryngeal squamous cell carcinomas(LSCC). METHOD: The expression and distribution of three antigens, human type IV collagen(CT IV), laminin(LN) and fibronectin(FN) were immunohistochemically determined in 72 cases of LSCC by using the corresponding monoclonal antibodies. The correlation of the intact continuance of ECM around the tumor nest with the cell differentiation, invasion mode and the regional lymph node metastasis of laryngeal squamous cell carcinoma was evaluated. RESULT: In cases with poor histological differentiation, the defect of ECM was more severe than that in cases with high or middle histological differentiation(P < 0.01). Moreover, cases with diffuse invasion revealed lower ECM expression compared with cases with better tumor-host border (P < 0.01). There was a higher risk of regional lymph node metastasis among cases with poor ECM expression (P < 0.01). And there was a significant association between the defect of ECM and the lymph node metastasis(P < 0.01). CONCLUSION: These observations indicates that testing the distribution and the expression of ECM seems to be useful to evaluate the histological grading of malignancy and the invasion mode of laryngeal squamous cell carcinoma and to be helpful to prognosticate the frequency of regional lymph node metastasis.

Adult↗
PubMed2003

[Clinical observation and histological research of vocal cord's reformation after laser cordectomy].

OBJECTIVE: Explore the reformation of new vocal cord after laser cordectomy and the histological change of new vocal cord by animal experiment. METHODS: The reforming course of new vocal cord was observed by follow-up. 4 dogs underwent bilateral cordectomy (type II operation) and their larynx were analyzed anatomically and histologically eight months later. 100 cases who underwent KTP laser cordectomy were divided into 3 types according to the range and depth of the excision. RESULTS: All the dogs had reformation of vocal cords eight months later. On the surface of the reformed vocal cord, no mucous cell but squamous cells was found. Newborn ligament-like connective tissues and loose muscle fibers were found under membrane. Complete reconstruction of larynx was found in 16 cases of type I (16/16) and 54 of type II 86% (54/63). But in type III no new vocal cord was found. CONCLUSION: Formation of the new vocal cord is the result of hypertrophy of the remained vocal cord muscle, influenced by depth of the excised vocal cord using laser. The histological construction is nearly normal cord. Whether or not the laser radiation stimulate the tissue hypertrophy is need more research.

Adult↗