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Zhong Guan

Publications and source records attributed to Zhong Guan.

7 recordsLinked to original sources
PubMed2026

Differences in circadian rhythm changes between myopic and non-myopic college students over 2 years.

This study aimed to characterize and compare the differences in circadian rhythm changes during 2 years between college students with myopia and non-myopia based on a longitudinal cohort study. Wake-up time and bedtime were obtained through a self-administered questionnaire. Chronotype was assessed using the reduced Morningness-Eveningness Questionnaire (rMEQ). Circadian rhythm timing was determined by dim-light melatonin onset (DLMO), measured through hourly saliva collection from 21:00 to 01:00. A total of 450 college students (146 [32.4%] males) with a mean age of 18.65 ± 1.05 years were included, of whom 353 (78.4%) students had myopia. Compared with non-myopic individuals, myopic students slept later, woke up earlier, and exhibited lower rMEQ scores at baseline. Over the 2-year follow-up, both groups showed significantly earlier bedtimes, later wake-up times, and higher rMEQ scores. Only myopic students demonstrated a 45-minute delay in DLMO after the 2-year follow-up. After adjusting for potential confounders, linear mixed-effects models showed that myopic individuals had later bedtimes and earlier wake-up times. These findings indicate significant circadian rhythm changes in individuals with myopia, suggesting the potential of targeted sleep rhythm interventions on preventing myopia.

Myopia↗
PubMed2006

Parametric and nonparametric FDR estimation revisited.

Nonparametric and parametric approaches have been proposed to estimate false discovery rate under the independent hypothesis testing assumption. The parametric approach has been shown to have better performance than the nonparametric approaches. In this article, we study the nonparametric approaches and quantify the underlying relations between parametric and nonparametric approaches. Our study reveals the conservative nature of the nonparametric approaches, and establishes the connections between the empirical Bayes method and p-value-based nonparametric methods. Based on our results, we advocate using the parametric approach, or directly modeling the test statistics using the empirical Bayes method.

Bayes Theorem↗
PubMed2006

[Repair of pharynx with acellular dermal matrix].

OBJECTIVE: To evaluate the clinical use of acellular dermal matrix (ADM) in the repair of pharynx. METHOD: From June 2003 to December 2004, 18 cases of laryngopharyngeal carcinoma or oropharyngeal carcinoma accepted treatment of surgery. Four of them had the tumor in the place of posterior wall of laryngopharynx or oropharynx. In the operation, the tumor was resected and the function of larynx was reserved, reconstruction of the posterior wall of laryngopharynx or oropharynx was made with ADM. Three of them had normal function of vocal cords and the tumor was in the place of posterior wall of pharynx and lateral wall of piriform fossa. These patients accepted resection of the tumor and the larynx was reserved. ADM was sutured to the prevertebral fascia to repair the pharynx, reinforcement was made with sternocleidomastoid muscle then. The other 11 patients had the tumor in the pharynx and cervico-esophagus and the vocal cords were fixed. These cases accepted total resection of the larynx and laryngopharynx. ADM was sutured to the prevertebral fascia to repair the posterior wall of laryngopharynx, musculo-cutaneous flap of pectoralis major muscle was made to repair the anterior and lateral walls. All these 18 patients accepted radiotherapy after the operation, the dosage was 60-70 Gy. RESULTS: Among all these 18 cases, no rejection of ADM or formation of pharynx fistula happened after the operation. The allograft became normal mucosa finally. Two patients had subcutaneous infection. After the treatment of dressing change and antibiotics, the wound healing was satisfying. All the 18 patients had resumption of oral diet finally but 3 of them had light mis-swallowing. Seven patients whose larynx were reserved had the trachea cannula pulled out The follow-up periods after the operation lasted 12 months to 30 months. The middle follow-up period was 19. 38 months. Neither rejection nor scar formation of the allograft happened. The follow-up of 11 patients lasted more than 18 months, 3 of them had relapse of tumor. After the second operation 1 patient was still alive and 2 patients died of distant metastasis. CONCLUSION: ADM can be easily obtained. Its histocompatibility were perfect The operative procedure were easy to perform. The complications of donor part can be totally avoided. The combined use of ADM and musculo-cutaneous flap of pectoralis major muscle or other neck tissue was safe and effective in the reconstruction of pharynx.

Aged↗
PubMed2004

A semiparametric approach for marker gene selection based on gene expression data.

MOTIVATION: Identification of differentially expressed genes is a major issue in gene expression data analysis and selection of marker genes is critical in tumor classification using gene expression data. In this paper, we propose a semiparametric two-sample test to identify both differentially expressed genes and select marker genes for sample classification. RESULTS: A simulation study shows that the proposed method is more robust and powerful than the methods, generally used such as t-tests and non-parametric rank-sum tests, when the sample size is small. Cross-validation shows that the sample classification based on genes selected using this semiparametric method has lower misclassification rates. CONTACT: hongyu.zhao@yale.edu.

Biomarkers, Tumor↗
PubMed2004

Study of Arabidopsis thaliana resistome in response to cucumber mosaic virus infection using whole genome microarray.

The plant innate immune response is mediated by resistance (R) genes and involves hypersensitive response (HR) cell death. During resistance responses, the host undergoes net changes in the transcriptome. To understand these changes, we generated a whole genome transcript profile for RCY1-mediated resistance to cucumber mosaic virus strain Y (CMV-Y) in Arabidopsis. Using a very stringent selection criterion, we identified 444 putative factors belonging to nine different functional classes that show significant transcript regulation during Arabidopsis-CMV-Y interaction. Genes with unknown function formed the largest class. Other functional classes represented in the resistome include kinases and phosphatases, protein degradation machinery/proteases, transcriptional regulators, and others. Interestingly, several of the unknown function genes possess well characterized domains and secondly many genes encode small peptides with less than 100 amino acids. Analysis of 1.1 kb promoter regions of the 444 genes revealed that 9 out of the 12 known cis-binding elements are significantly associated with pathogen responsive cluster. Location and distribution of five prominent binding elements for select group of disease resistance related and unknown function genes is presented. The analysis also revealed 80 defense-responsive genes that might participate in R gene-mediated defense against both viral and bacterial pathogens. In addition, chromosome distribution of genes that respond to bacterial and viral pathogens suggests that they are located in small gene clusters and may be transcriptionally co-regulated. Exploring the precise function of the new genes identified in this analysis will offer new insights into plant defense.

Analysis of Variance↗
PubMed2004

[Relationship between expression of survivin and prognosis in human laryngeal squamous cell carcinoma].

BACKGROUND & OBJECTIVE: A novel inhibitor of apoptosis Survivin has recently been found in many common human cancers but not in normal tissues. Its potential distribution in human laryngeal squamous cell carcinoma (HLSCC) and its implication for inhibition of apoptosis were not yet very clear. This study was designed to investigate the expression of survivin and the probabilities of using it as a new indicator of the prognosis of HLSCC. METHODS: HLSCC samples from 71 patients treated in Department of Otorhinolaryngology, Second Affiliated Hospital of Sun Yat-sen University between 1995 and 1998 were analyzed for survivin expression by immunohistochemistry method. The patients were followed-up for long term and the relationship between survivin expression and clinical data including age, gender, classification, clinical type, pathological type, lymph node metastasis, distant metastasis, and prognosis were analyzed using software SPSS11.0. RESULTS: The expression rate was 50.7% (36/71) in all 71 cases. The expression rate was 81.8% (9/11) in the cases with lymph nodes metastasis, which was higher than that in the cases without lymph nodes metastasis (45%, 27/60), with significant difference (P=0.025). Univariate analysis revealed that classification,type and survivin expression were significantly related to the prognosis of HLSCC. P value were 0.0001, 0.009, and 0.0008, respectively. Multivariate analysis demonstrated that the patients with positive survivin had significant shorter survival (63.5 months) than those with negative survivin (84.0 months) (P=0.006) except the effect of classification and type on the prognosis of HLSCC. CONCLUSION: Survivin expressed in HLSCC especially in the cases with lymph nodes metastasis. Its expression may related to the prognosis of HLSCC.

Carcinoma, Squamous Cell↗
PubMed2003

PathMAPA: a tool for displaying gene expression and performing statistical tests on metabolic pathways at multiple levels for Arabidopsis.

BACKGROUND: To date, many genomic and pathway-related tools and databases have been developed to analyze microarray data. In published web-based applications to date, however, complex pathways have been displayed with static image files that may not be up-to-date or are time-consuming to rebuild. In addition, gene expression analyses focus on individual probes and genes with little or no consideration of pathways. These approaches reveal little information about pathways that are key to a full understanding of the building blocks of biological systems. Therefore, there is a need to provide useful tools that can generate pathways without manually building images and allow gene expression data to be integrated and analyzed at pathway levels for such experimental organisms as Arabidopsis. RESULTS: We have developed PathMAPA, a web-based application written in Java that can be easily accessed over the Internet. An Oracle database is used to store, query, and manipulate the large amounts of data that are involved. PathMAPA allows its users to (i) upload and populate microarray data into a database; (ii) integrate gene expression with enzymes of the pathways; (iii) generate pathway diagrams without building image files manually; (iv) visualize gene expressions for each pathway at enzyme, locus, and probe levels; and (v) perform statistical tests at pathway, enzyme and gene levels. PathMAPA can be used to examine Arabidopsis thaliana gene expression patterns associated with metabolic pathways. CONCLUSION: PathMAPA provides two unique features for the gene expression analysis of Arabidopsis thaliana: (i) automatic generation of pathways associated with gene expression and (ii) statistical tests at pathway level. The first feature allows for the periodical updating of genomic data for pathways, while the second feature can provide insight into how treatments affect relevant pathways for the selected experiment(s).

Arabidopsis↗