First Trimester Aneuploidy Screening Using Nuchal Iranslucency, Free Beta Human Chorionic Gonadotrophin and Maternal Age

Summary: Screening for aneuploidy using maternal age has a low detection rate and high false positive rate. Second trimester maternal serum screening increases trisomy 21 detection and decreases die false positive rate. First trimester screening would enable definitive diagnosis with chorionic villus sampling, and simple surgical termination of affected pregnancies would still be an option. Nuchal translucency (NT), free beta human chorionic gonadotrophin (fβHCG) and maternal age were assessed in 302 patients before chorionic villus sampling. NT positively and fβHCG negatively correlated with gestation, but neither correlated with maternal age nor with each other. Both NT and fβHCG were increased in trisomy 21. NT was increased and fβHCG was decreased in trisomy 18. Multivariate discriminant analysis enabled 87.5% detection of trisomy 21 in this high-risk population, for a 14% false positive rate. In a simulated normal population, using a risk cut-off of 1 in 250, 71% detection was achieved for a 7% false positive rate. The combination of NT, fβHCG and maternal age is a simple, readily available and viable first trimester screening strategy.     

The hospital record of the injured child and the need for external cause-of-injury codes. American Academy of Pediatrics. Committee on Injury and Poison Prevention, 1998-1999

Proper record-keeping of emergency department visits and hospitalizations of injured children is vital for appropriate patient management. Determination and documentation of the circumstances surrounding the injury event are essential. This information not only is the basis for preventive counseling, but also provides clues about how similar injuries in other youth can be avoided. The hospital records have an important secondary purpose; namely, if sufficient information about the cause and mechanism of injury is documented, it can be subsequently coded, electronically compiled, and retrieved later to provide an epidemiologic profile of the injury, the first step in prevention at the population level. To be of greatest use, hospital records should indicate the "who, what, when, where, why, and how" of the injury occurrence and whether protective equipment (eg, a seat belt) was used. The pediatrician has two important roles in this area: to document fully the injury event and to advocate the use of standardized external cause-of-injury codes, which allow such data to be compiled and analyzed.     

Combined DNA methyltransferase and histone deacetylase inhibition in the treatment of myeloid neoplasms

Optimal reexpression of most genes silenced through promoter methylation requires the sequential application of DNA methyltransferase inhibitors followed by histone deacetylase inhibitors in tumor cell cultures. Patients with myelodysplastic syndrome or acute myeloid leukemia (AML) were treated with the methyltransferase inhibitor 5-azacitidine (aza-CR) followed by the histone deacetylase inhibitor sodium phenylbutyrate. Major responses associated with cytogenetic complete response developed in patients receiving prolonged dosing schedules of aza-CR. Bisulfite sequencing of the p15 promoter in marrow DNA during the first cycle of treatment showed heterogeneous allelic demethylation in three responding patients, suggesting ongoing demethylation within the tumor clone, but no demethylation in two nonresponders. Six of six responding patients with pretreatment methylation of p15 or CDH-1 promoters reversed methylation during the first cycle of therapy (methylation-specific PCR), whereas none of six nonresponders showed any demethylation. Gene demethylation correlated with the area under the aza-CR plasma concentration-time curve. Administration of both drugs was associated with induction of acetylation of histones H3 and H4. This study provides the first demonstration that molecular mechanisms responsible for responses to DNA methyltransferase/histone deacetylase inhibitor combinations may include reversal of aberrant epigenetic gene silencing. The promising percentage of major hematologic responses justifies the testing of such combinations in prospective randomized trials.     

Differential requirement for DNA methyltransferase 1 in maintaining human cancer cell gene promoter hypermethylation

Previous work has shown that DNA hypermethylation of tumor suppressor genes in colorectal cancer cells may be maintained in the absence of the major mammalian methyltransferase, DNA methyltransferase 1 (DNMT1). In an effort to dissect the dependency on DNMT1 to maintain such hypermethylation in different cancer types, we performed a systematic analysis of depletion of DNMT1 in colorectal (SW48), bladder (T24), and breast (T47D) cancer cells by DNMT1-specific small hairpin RNA (shRNA) targeting. We show that although DNMT1-deficient SW48 and T24 cells exhibited no observable growth defects and were able to maintain promoter hypermethylation, DNMT1-deficient T47D breast cells failed to form comparable numbers of colonies when stably selected for the incorporation of the DNMT1-specific shRNA expression vector, suggesting a growth defect with reduced levels of DNMT1. Further treatment of T47D cells with transient transfection of small interfering RNA targeting DNMT1 revealed that severely DNMT1-deficient T47D cells could not fully maintain promoter hypermethylation, and gene silencing was partially reversed at two of the three assayed loci. These observations suggest that human cancer cells may differ in their reliance on DNMT1 for maintaining DNA methylation.     

出血热误诊为上呼吸道感染1例

1病例报告患者,男,22岁,因间歇性全身乏力、肌肉酸痛2 wk,发冷1 wk,发热4 d入院.曾在我院查WBC 4.5×109/L,N 0.60,L 0.4,体温波动在38～40℃.初步诊断"上呼吸道感染",用阿莫西林、VC银翘片、清热解毒冲剂等治疗无效.查体:T 38.9℃,BP面性12/8 kPa.全身皮肤无出血点,双眼球结膜轻度充血,咽部充血,软腭未见充血点,心肺腹部未见阳性体征.实验室检查:WBC 7.85 × 109/L,N 0.79,L 0.21,HGB 150g/L,PCL30×109/L,尿蛋白3.2g/L,流行性出血热抗体( ).诊断:流行性出血热.入院后立即按照流行性出血热的治疗原则给予抗病毒、抗渗出、抗出血治疗.具体包括卧床休息,给予高热量,多维生素,易消化饮食;维持水、电解质、酸碱及血浆渗透压平衡;给予大剂量(5 g)Vit.C和Vit.E.同时给予氢化可地松100 mg/d,稀释后缓慢静脉滴注.入院后3 d患者的尿量由450 mL/d增至750 mL/d,肌酐204.6μmol/L,BUN 13.3 mmol/L.5 d尿量增加至4000 mL/d.经综合治疗10 d,肌酐和BUN检查等正常,痊愈出院,随访1 mo未见异常.     

Prognostic importance of promoter hypermethylation of multiple genes in esophageal adenocarcinoma

PURPOSE: We investigated aberrant methylation patterns in esophageal adenocarcinoma and correlated the findings to patient survival and tumor recurrence. Experimental Design: Gene promoter methylation was performed in 82 samples from 41 esophagectomy patients consisting of 41 adenocarcinoma samples, each with its adjacent nonmalignant tissue, which included one sample with Barretts metaplasia. The methylation status of seven genes was determined. Epigenetic silencing was confirmed using immunohistochemical staining. Kaplan-Meier plots were constructed using disease-specific survival as the primary end point and the interval from surgery to tumor recurrence as the secondary end point. The association of clinicopathological and biomolecular risk factors to survival and recurrence was performed using the Log-rank test and Cox proportional hazards model for multivariate analysis. RESULTS: Methylation frequencies of the genes analyzed were APC, 68%; E-cadherin, 66%; O(6)-methylguanine DNA methyltransferase, 56%; ER, 51%; p16, 39%; DAP-kinase, 19%; and TIMP3, 19%. DNA methylation of some genes individually showed only trends toward diminished survival, whereas patients whose tumors had >50% of their gene profile methylated had both significantly poorer survival (P = 0.04) and earlier tumor recurrence (P = 0.05) than those without positive methylation. By multivariate analysis, the hazard ratios (HRs) with positive methylation status were more powerful predictors of survival [HR 2.7 (1.14-6.45; 95% confidence interval)] and tumor recurrence [HR 2.5 (1.11-5.6)] than age (HR 2.03 and 1.96, respectively) or stage (HR 1.48 and 1.67, respectively). CONCLUSIONS: Our data suggest that positive methylation status for multiple genes in esophageal adenocarcinoma is a predictor of poor prognosis.     

Histone modifications and silencing prior to DNA methylation of a tumor suppressor gene

We attempted to answer two central questions about epigenetic silencing of the tumor suppressor gene p16(INK4a) in this study: (1) whether the maintenance of associated histone modifications is dependent on DNA methylation and (2) whether such histone modifications can occur prior to DNA methylation. By coupling chromatin immunoprecipitation with gene targeting and the analysis of specific alleles, we found that elimination of DNA methylation from a p16(INK4a) allele resulted in profound changes in surrounding histones. After continued passage of such cells, methylation of histone H3 lysine-9 occurred in conjunction with re-silencing in the absence of DNA methylation. These results have important implications for understanding the biochemical events underlying the silencing of tumor suppressor genes and the resultant growth suppression.