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Biomedical subjects

C Guo

Publications and source records attributed to C Guo.

At least 73 records · Page 4Linked to original sources
PubMed2000

Localization of a hereditary neuroblastoma predisposition gene to 16p12-p13.

BACKGROUND: Hereditary predisposition to develop neuroblastoma segregates as an autosomal dominant Mendelian trait. PROCEDURE: We have performed linkage analysis on 10 families with neuroblastoma to localize a hereditary neuroblastoma predisposition gene (HNB1). RESULTS: A single genomic interval at chromosome bands 16p12-p13 was consistent with linkage (lod = 3.46), and identification of informative recombinants defined a 25.9-cM critical region between D16S748 and D16S3068. Loss of heterozygosity was identified in 5/12 familial (42%) and 55/259 nonfamilial (21%) neuroblastomas at multiple 16p polymorphic loci. A 12.8-cM smallest region of overlap of deletions was identified within the interval defined by linkage analysis (tel-D16S764-D16S412-cen). CONCLUSIONS: Taken together, these data suggest that HNB1 is located at 16p12-p13 and that inactivation of this gene may contribute to the pathogenesis of nonfamilial neuroblastomas.

Child↗
PubMed2000

Deletion of 11q23 is a frequent event in the evolution of MYCN single-copy high-risk neuroblastomas.

BACKGROUND: Deletions of the long arm of chromosome 11 are frequently identified in human neuroblastomas. PROCEDURE: We screened 394 primary neuroblastomas and 52 tumor-derived cell lines with a panel of 11q and 11p polymorphic markers to determine the frequency of chromosome 11 allelic deletion, and to differentiate partial deletions of chromosome 11q (unb[11q] LOH) from whole chromosome loss. RESULTS: Allelic deletion occurred most frequently at cytogenetic band 11q23 and was detected in 161 primary neuroblastomas (41%) and 18 cell lines (35%). Eighty-seven tumors (22%) had unb[11q] LOH with a heterogeneous distribution of deletion breakpoints. Unb[11q] LOH was highly correlated with age > 1 year at diagnosis (P = 0.008), stage 4 disease (P = 0.001), unfavorable Shimada histopathology (P < 0.001), and assignment to a high-risk therapeutic protocol (P < 0.001), and was inversely correlated with MYCN amplification (P = 0.018). Patients whose tumors showed unb[11q] LOH were less likely to survive (P < 0.001), but there was only a trend towards an independent prognostic influence in multivariate analyses. CONCLUSIONS: Thus, structural rearrangements resulting in unb[11q] LOH commonly occur during the malignant evolution of high-risk neuroblastomas with single-copy MYCN.

Alleles↗
PubMed2000

Outer-ring stereochemical modulation of cytotoxicity in cephalostatins.

[structure: see text] 20- and 25'-epimers of cephalostatin 7, prepared by directed unsymmetrical pyrazine synthesis, address outer-ring topographical and stability questions and intimate an oxacarbenium ion rationale for the role in bioactivity of the spiroketal (E/F, E'/F') rings of this class of antitumor agents.

Animals↗
PubMed2000

Left ventricular tachycardia originating near the left main coronary artery.

Eight patients with idiopathic ventricular tachycardia (VT) underwent mapping and radiofrequency ablation. Mapping showed VT originating in the high posterolateral left ventricular outflow tract in proximity to the left main and proximal circumflex coronary arteries. Ablation was not attempted due to this proximity to the left main and proximal circumflex coronary arteries. Ablation was not attempted due to this proximity in 2 patients and limited in 1 patient. It was successful in VT suppression in 5 of 6 patients.

Adult↗
PubMed2000

A noninvasive transesophageal signal averaging technique for detection of sinus node electrogram.

We have developed a noninvasive transesophageal signal averaging technique for direct recording of sinus node electrogram. In this study, sinus node electrograms were recorded from 106 of 138 patients (77%), comparable to that (46%) recorded by conventional transesophageal technique, 59 were male and 47 were female ranging in age from 10-74 years (mean 44.2+/-12.4 years). The signals from lead I, surface averaged lead and esophagus averaged lead were amplified (up to 100 microV/cm), filtered (0.1-50 Hz), AD converted to 16-bit accuracy at a sampling rate of 2 KHz and averaged by using the three channel low-noise amplifier. The signal averaged esophageal sinus node potentials are deflections of low-amplitude and low-frequency preceding the P wave. Two morphologies, the domed wave (64 of 106 patients, 60%) and the smooth upstroke slope (42 of 106 patients, 40%), can be seen. The directly recorded sinoatrial conduction time was 82.3 +/-18.6 msec (mean+/-2 SD), ranged from 23-112 msec, amplitude was 3.8-27.7 microV and dv/dt was 0.42-1.92 mV/sec. The sinoatrial conduction time recorded by the transesophageal catheter technique was comparable to that (80.4+/-18. 1 msec) recorded by the transvenous catheter method perfectly. We think that signal averaged sinus node electrogram could be recorded in sinus rhythm in most patients with normal sinus node function and proper filter settings, high amplification and anti-drift technique are important in recording signal averaged esophageal sinus node electrogram.

Adolescent↗
PubMed2000

Behavioral and emotional problems in Chinese children of divorced parents.

OBJECTIVE: This study examined the behavioral problems in Chinese children of divorced parents. METHOD: A total of 58 children of divorce and 116 gender-, age-, and school class-matched controls were ascertained from a general population sample of children aged 6 through 15 years. Parents completed the Child Behavior Checklist (CBCL), and teachers completed the Teacher's Report Form (TRF) and Conners Hyperkinesis Index. RESULTS: Parent-reported problem scores on the CBCL total scale and each subscale, and prevalence of all CBCL syndromes except for Somatic Complaints, were significantly higher in children of divorce than in controls. Teacher-reported problem scores on the TRF total scale and Social and Attention Problems and prevalence of Attention Problems were significantly different for the 2 groups of children. Social competence was rated significantly lower in children of divorce than in controls. Discriminant function analysis showed that behavioral problems in children of divorce were characterized by aggressive behavior, withdrawal, and social problems. CONCLUSIONS: The findings emanating from China provide the first evidence of the link between parental divorce and children's psychopathology and clarify the psychopathological dimensions in Chinese children of divorced parents.

Adolescent↗
PubMed2000

Loss of heterozygosity at 1p36 independently predicts for disease progression but not decreased overall survival probability in neuroblastoma patients: a Children's Cancer Group study.

PURPOSE: To determine the independent prognostic significance of 1p36 loss of heterozygosity (LOH) in a representative group of neuroblastoma patients. PATIENTS AND METHODS: Diagnostic tumor specimens from 238 patients registered onto the most recent Children's Cancer Group phase III clinical trials were assayed for LOH with 13 microsatellite polymorphic markers spanning chromosome band 1p36. Allelic status at 1p36 was correlated with other prognostic variables and disease outcome. RESULTS: LOH at 1p36 was detected in 83 (35%) of 238 neuroblastomas. There was a correlation of 1p36 LOH with age at diagnosis greater than 1 year (P = .026), metastatic disease (P<.001), elevated serum ferritin level (P<.001), unfavorable histopathology (P<.001), and MYCN oncogene amplification (P<.001). LOH at 1p36 was associated with decreased event-free survival (EFS) and overall survival (OS) probabilities (P<.0001). For the 180 cases with single-copy MYCN, 1p36 LOH status was highly correlated with decreased EFS (P = .0002) but not OS (P = .1212). Entering 1p36 LOH into a multivariate regression model suggested a trend toward an independent association with decreased EFS (P = .0558) but not with decreased OS (P = .3687). Furthermore, allelic status at 1p36 was the only prognostic variable that was significantly associated with decreased EFS in low-risk neuroblastoma patients (P = .0148). CONCLUSION: LOH at 1p36 is independently associated with decreased EFS, but not OS, in neuroblastoma patients. Determination of 1p36 allelic status may be useful for predicting which neuroblastoma patients with otherwise favorable clinical and biologic features are more likely to have disease progression.

Child↗
PubMed2000

Mitogenic signaling in androgen sensitive and insensitive prostate cancer cell lines.

PURPOSE: To investigate the role of a specific mitogen activated protein kinase, extracellular signal-regulated kinase (ERK), in regulating cell proliferation induced by three potentially important prostate cancer mitogens that signal via different classes of receptors. MATERIALS AND METHODS: Androgen sensitive (LNCaP) and insensitive (PC-3) prostate cancer cell lines were used in these studies. Epidermal growth factor (EGF), lysophosphatidic acid (LPA), and dihydrotestosterone (DHT) were the mitogenic stimulants and AG1478, a receptor tyrosine kinase inhibitor, and PD98059, an inhibitor of MEK, were the chemical inhibitors used in this study. Cell proliferation was measured using the WST-1 assay and ERK expression and activation was determined by immunoblotting for phospho- and total ERK. RESULTS: In androgen-sensitive LNCaP cells, epidermal growth factor (EGF) and dihydrotestosterone (DHT) both enhanced cell proliferation. EGF-stimulation dramatically increased ERK phosphorylation while DHT did not. In the androgen-insensitive cell line, PC-3, EGF- and LPA-induced ERK phosphorylation and cell proliferation. Inhibition of EGF- and LPA- induced ERK activation with the EGF receptor inhibitor, AG1478, or the MEK inhibitor, PD98059, attenuated their proliferative effects. Neither inhibitor had an effect on DHT stimulated cell proliferation. CONCLUSIONS: These data demonstrate heterogeneity of mitogenic signaling in prostate cancer cells, and support the hypothesis that androgens and growth factors utilize divergent signaling pathways in prostate cancer to induce proliferation.

Cell Division↗
PubMed2000

Behavioral and emotional problems in Chinese children: teacher reports for ages 6 to 11.

This study examined the applicability of the Chinese Version of Teacher's Report Form (TRF-CV) and estimated the prevalence of behavioral problems in a general population sample of 2,936 children aged 6 through 11 years in the Shandong Province of China. Teachers completed the TRF-CV and the Conners Hyperkinesis Index (CHI). The TRF-CV total scale showed satisfactory 2-week test-retest reliability (r = .83) and internal consistency (Cronbach's alpha = .94). The TRF-CV Total Problems, Attention Problems, Delinquent Behavior, and Aggressive Behavior had acceptable concurrent validity with the CHI (mean r = .62). With the TRF-CV Total Problems score of 26 as a cutoff, an overall correct classification rate of 90% for clinical sample and nonreferral required children was obtained. Exploratory factor analysis yielded six syndromes: Aggressive/Delinquent Behavior, Withdrawn/Depressed, Somatic Complaints, Attention Problems, Social Problems, and Thought Problems, with significant correlations with corresponding American cross-informant syndromes (mean r = .84). The overall prevalence rate of behavioral problems was 15.5% (95% CI = 14.2-16.8%), with a boy-to-girl ratio of 2.0:1 (chi2 = 59.70, p < .001). Younger boys exhibited more externalizing problems. These findings indicate that the TRF-CV is applicable for Chinese children, and the prevalence of behavioral problems shown by it among Chinese children seems comparable to that found in other countries. Although most of the American syndromes were well replicated, the differences in the present subjects, when submitted to principal components analysis, from American samples from whom the original syndromes were derived, could have prevented the study from replicating distinctions between aggressive vs. delinquent and depressed vs. withdrawn syndromes.

Affect↗
PubMed2000

[Genetic polymorphism of 5 STR loci on chromosome 14 in Chinese Han].

OBJECTIVE: To understand the distribution of genes and genotypes of 5 STR loci on chromosome 14 in Chinese Han. METHODS: PCR and polyacrylamide gel electrophoresis were used to analyze the polymorphism of 5 STR loci (D14S742, D14S306, D14S606, D14S617, D14S611) on chromosome 14 in Chinese Han. RESULTS: 5 alleles and 13 genotypes, 5 alleles and 13 genotypes, 6 alleles and 13 genotypes, 9 alleles and 21 genotypes, and 6 alleles and 13 genotypes were observed at D14S742, D14S306, D14S606, D14S617 and D14S611, respectively. The frequencies of the most common allele at these five loci were 0.31, 0.31, 0.47, 0.35 and 0.29 respectively. CONCLUSION: These five loci are highly polymorphic in Chinese Han and their allele distribution is in good agreement with Hardy-Weinberg equilibrium.

China↗
PubMed2000

Genetic polymorphism of 4 STR loci on chromosome 17 in Chinese Han.

OBJECTIVE: To analyze genetic polymorphism of D17S1290, D17S1293, D17S1303 and D17S1308 in Chinese Hans. METHODS: Fifty unrelated individuals were analyzed by PCR amplification fragment length polymorphism analysis method. RESULTS: 9, 7, 5, 5 alleles were observed at these 4 STR loci respectively, the genotypes distributions in Chinese Hans were in accordance with Hardy-Weinberg equilibrium, the expected heterozygosities for these loci were 0.770, 0.828, 0.608, 0.669 respectively, the polymorphism information contents(PIC) were 0.763, 0.820, 0.602, 0.662 respectively. CONCLUSION: The results demonstrate these 4 STR loci can be used for genetic analysis.

China↗
PubMed2000

[The development of degenerative disc animal model in rhesus monkey].

OBJECTIVE: To develop the degenerative disc animal model with histological and MRI observation. METHODS: Eight adult Rhesus monkeys were divided randomly into two groups after the lumbar discs MRI scan. The operated group, 6 monkeys, was subjected to annulus resection. A 5 mm x 3 mm cut was made in the left anterolateral part of the fibrosus annulus on L(4,5), L(5,6) and L(6,7) discs. The operated discs were scanned with MRI at 1 week, 4 weeks, 8 weeks, 13 weeks and 20 weeks postoperatively and observed histologically at 4 weeks, 8 weeks and 20 weeks after operation. RESULTS: The histological structure of Rhesus monkey was similar to that of human being. The percentage of high signal intensity area in the operated discs reduced significantly at 8, 13, 20 weeks after operation (P < 0.05). The fibroplasia outside the annular tear could be observed in all 6 operated discs at 4 weeks postoperatively. Two of 6 operated discs underwent fibroplasia at 20 weeks after operation. No heal evidence in the inner tear was showed after operation. CONCLUSIONS: The animal model for human lumbar disc degeneration could be obtained by anterio-lateral annulus resection. The early-stage degenerative evidence could be observed without injury by measuring the percentage of the high intensity area of the operated discs on T2WI of MRI.

Animals↗
PubMed2000

[A study on incidence of injury and its socio-economic loss in children and young adults].

OBJECTIVES: To study the current status of incidence of injury among children and young adults and the causes of common injuries, and to estimate its socio-economic loss and extent of harmfulness. METHODS: Pupils in 19 primary and middle schools aged 7 to 18 years, totaling 14,533, were recruited with stratified cluster sampling during 1998 to 1999 in Guangzhou, Maoming, Jiangmen and Shantou. Judgement for injury was based on the following criteria: (1) diagnosed and treated in hospitals or school clinics, (2) a half-day off or more due to injury, and (3) emergency management by pupils' parents or teachers. RESULTS: There were 6 941 pupils suffered from varied injures during the year, with an incidence rate of 47.76% (50.08% for boys and 45.02% for girls). Incidence rate of injury was higher in the middle school pupils (13 - 18 years old, 58.49%) than that in the primary school pupils (7 - 12 years old, 40.08%). The incidence increased significantly with age, with a peak at ages of 13 - 15. Major causes of injuries resulted from falls, injury by sharp articles, collision, traffic injuries and burn/scalds, etc, which usually occurred due to carelessness in sports, playing, walking, bike-riding and working. Frequency of multiple injuries related to the educational level of parents and depended on whether or not an only-child in family. There were 2,173 injured pupils (accounting for 31.3% of the total) visited clinics or emergency department in hospitals and 627 (9.0%) hospitalized for treatment. Twenty-eight percent of the injured pupils were absent from school, with an average absenteeism of 5.6 days. There were 154 injured pupils with transient disability and 53 with permanent disability, with a disability rate of 410.47 per 100,000. Cost for their medical care averaged 81.5 yuan RMB per injured pupil. CONCLUSIONS: Injury was a common and frequently-happened incident among children and young adults and could seriously affect their health, development and growth, studying and their future of children and young adults. Health education, safety-promotion and removing hidden danger for injury are the major measures to prevent from injury, and the government and the whole society should pay great attention to injury issues in children and young adults.

Accidents↗