The concentration of circulating corticotropin-releasing hormone mRNA in maternal plasma is increased in preeclampsia.

Background: Increased fetal DNA in maternal plasma/serum has been reported in pregnancies complicated by preeclampsia. We hypothesize that fetal RNA may also be increased in maternal plasma in preeclampsia.

Methods: We developed a real-time quantitative reverse transcription-PCR assay to measure the concentration of the mRNA of the corticotropin-releasing hormone (CRH) locus.

Quantitative analysis of circulating mitochondrial DNA in plasma.

Background: Recent studies have demonstrated the existence of circulating mitochondrial DNA in plasma and serum, but the concentrations and physical characteristics of circulating mitochondrial DNA are unknown. The aim of this study was to develop an assay to quantify mitochondrial DNA in the plasma of healthy individuals.

Methods: We adopted a real-time quantitative PCR approach and evaluated the specificity of the assay for detecting mitochondrial DNA with a cell line (rho(0)) devoid of mitochondria.

Cell-free nucleic acids in plasma, serum and urine: a new tool in molecular diagnosis.

There has recently been an upsurge of interest in the analysis of circulating nucleic acids (DNA and/or RNA) in blood plasma or serum as a clinical diagnostic tool. Occasional earlier reports suggested the existence of circulating nucleic acids, but the potential clinical implication was not realized until 1996, when DNA with tumour-specific characteristics was demonstrated in the plasma/serum of cancer patients. This finding opened up possibilities for non-invasive cancer diagnosis.

Prognostic use of circulating plasma nucleic acid concentrations in patients with acute stroke.

Background: At present there is no simple, accurate blood test that may be used to determine the severity of stroke or to predict mortality and morbidity in stroke patients presenting to emergency departments.

Methods: Patients with stroke-like symptoms who presented to an emergency department of a university hospital in Hong Kong were recruited for the study. DNA extracted from patients' plasma was analyzed for the beta-globin gene with a fluorescent-based PCR test.

mRNA of placental origin is readily detectable in maternal plasma.

The discovery of circulating fetal nucleic acid in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. Thus far, a gender- and polymorphism-independent fetal-specific target that can be used for prenatal screening and monitoring in all pregnant women has not been reported. In addition, the origin of such circulating nucleic acid has remained unclear.

Quantitative analysis of tumor-derived methylated p16INK4a sequences in plasma, serum, and blood cells of hepatocellular carcinoma patients.

Purpose And Experimental Design: Using real-time quantitative methylation-specific PCR (RTQ-MSP), we quantified methylated p16INK4a sequences and determined the fractional concentrations of circulating tumor DNA in plasma, serum, and peripheral blood cells collected preoperatively, intraoperatively, and postoperatively from 49 patients with hepatocellular carcinoma (HCC).

Results: RTQ-MSP was sufficiently sensitive to detect down to 10 genome-equivalents of methylated p16INK4a sequences. Quantitative MSP data were expressed in terms of the methylation index, which was the percentage of bisulfite converted unmethylated and methylated p16INK4a sequences that consisted of methylated p16INK4a sequences.

Non-invasive prenatal diagnosis: on the horizon?

The launch of the genomics and postgenomics era has greatly expanded our understanding of the genetic basis of many diseases. In conjunction with the sociocultural trend to delay childbirth and to maintain smaller family units, extra demand may be placed on the existing prenatal diagnostic services. The inherent risk of fetal loss associated with current prenatal diagnostic procedures, such as amniocentesis and chorionic villus sampling, has spurred research into non-invasive prenatal diagnosis.

Circulating EBV DNA as a tumor marker for nasopharyngeal carcinoma.

The demonstration of Epstein-Barr virus (EBV) DNA in the plasma/serum of patients suffering from nasopharyngeal carcinoma (NPC) has provided us with a new tool for NPC detection and monitoring. The sensitivity and specificity of using circulating EBV DNA for the detection of NPC, with real-time polymerase chain reaction analysis, is 96 and 93%, respectively. EBV DNA level has been shown to be more powerful than existing staging system in predicting outcomes and it could also identify patients with emergent clinical relapse.

Fetal DNA clearance from maternal plasma is impaired in preeclampsia.

Background: Increased fetal DNA in maternal plasma/serum has been reported in pregnancies complicated by preeclampsia. We hypothesized that impaired clearance of fetal DNA might contribute, at least in part, to the above-mentioned phenomenon.

Methods: We studied 7 preeclamptic and 10 control pregnant women.

Plasma Epstein-Barr virus DNA and residual disease after radiotherapy for undifferentiated nasopharyngeal carcinoma.

Background: Epstein-Barr virus (EBV) DNA can be detected and quantified in the plasma of patients with EBV-related tumors, such as nasopharyngeal carcinoma (NPC). Although NPC at early stages can be cured by radical radiotherapy, there is a high recurrence rate in patients with advanced NPC. The pretreatment level of circulating EBV DNA is a prognostic factor for NPC, but the prognostic value of post-treatment EBV DNA has not been studied.

Nasopharyngeal carcinoma in situ (NPCIS)--pathologic and clinical perspectives.

Background: Dysplasia or carcinoma in situ lesions (NPCIS) of the nasopharynx have rarely been reported. The prevalence, biologic behavior, and the transformation period of the pure preinvasive lesions have not been fully explained.

Methods: All cases of NPCIS were retrospectively reviewed during the period between 1990 and 2000.

Prenatal exclusion of beta thalassaemia major by examination of maternal plasma.

The discovery of the presence of fetal DNA in maternal plasma has provided a new approach for non-invasive prenatal diagnosis. At present, the prenatal diagnosis of beta thalassaemia relies on invasive methods. We designed allele-specific primers and a fluorescent probe for detection of the codon 41/42 (-CTTT) mutation in the beta globin gene from maternal plasma by real-time PCR.

New markers for cancer detection.

Circulating tumor nucleic acids in blood have been demonstrated to reflect the biologic characteristics of tumors. During tumor progression, aberrant DNA methylation can lead to transcriptional silencing of tumor suppressor genes, DNA repair genes, and metastasis-inhibitor genes. Hypermethylation of multiple genes, detectable in the blood of cancer patients, has demonstrated increasing promise as a specific and sensitive molecular marker for detecting and monitoring cancer.

Male microchimerism in healthy women and women with scleroderma: cells or circulating DNA? A quantitative answer.

Male DNA, of presumed fetal origin, can be detected in the maternal circulation decades after delivery and is referred to as fetal microchimerism (FM). We previously found quantitatively greater FM in the circulation of women with the autoimmune disease scleroderma (SSc) than of healthy women. However, it is unknown whether this difference is due to intact circulating cells or free DNA released from breakdown in disease-affected tissues.

Stability of endogenous and added RNA in blood specimens, serum, and plasma.

Background: Circulating RNA in plasma/serum is an emerging field for noninvasive molecular diagnosis. Because RNA is widely thought to be labile in the circulation, we investigated the stability and various preanalytical factors that may affect RNA concentrations in blood specimens.

Methods: Blood samples were collected from 65 healthy volunteers.

Presence of filterable and nonfilterable mRNA in the plasma of cancer patients and healthy individuals.

Background: As RNA is labile, we investigated whether circulating RNA in human plasma may be present in a particle-associated form.

Methods: Blood was collected from 27 healthy individuals and 16 hepatocellular carcinoma (HCC) patients. The plasma from each individual was processed by two means: filtration through filters with different pore sizes (from 5 microm to 0.

Plasma nucleic acids in the diagnosis and management of malignant disease.

Background: There is a need for development of molecular markers of cancer that can be used clinically for the detection, prognostication, and monitoring of cancer. Recently, there has been much interest in the potential use of nucleic acid markers in plasma and serum for this purpose.

Approach: We reviewed published literature up to 2002 on the topic, with a particular emphasis on reports published between 1996 and 2002.

Application of fetal DNA in maternal plasma for noninvasive prenatal diagnosis.

Prenatal diagnosis of fetal genetic conditions is a standard part of modern obstetric care. Many of the current methods rely on invasive methods and are associated with an inherent risk of fetal loss. Consequently, there has been a long-term goal for development of noninvasive prenatal diagnostic methods.