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Nicole Y L Lam

Publications and source records attributed to Nicole Y L Lam.

10 recordsLinked to original sources
PubMed2006

Comparison of plasma beta-globin DNA and S-100 protein concentrations in acute stroke.

BACKGROUND: This study aimed to compare changes in plasma beta-globin DNA and serum S100 protein to diagnose stroke and for predicting mortality and morbidity. METHODS: Patients with stroke-like symptoms presenting to the emergency department of a Hong Kong hospital were recruited. Plasma DNA was analyzed for the beta-globin gene with fluorescent-based PCR. S100 concentrations were determined using ELISA. Primary outcomes were diagnosis of stroke, mortality, and modified Rankin Score (mRS) after 6 months. RESULTS: One hundred ninety-seven consecutive patients recruited, 118 (60%) ischemic stroke, 35 (18%) hemorrhage and 44 (22%) with no acute neuroimaging changes. Serum S100 and plasma DNA were increased in 126 (p<0.0010) and 36 (p=0.21) stroke patients respectively vs. controls. Median plasma DNA was higher in hemorrhagic stroke than those without (1725 vs. 1050 kilogenome-equivalents/l, p=0.0104). Median plasma DNA was higher in mRS>2 vs. mRS 2 patients vs. mRS<or=2 (0.152 vs. 0.131 microg/l, p=0.0003). The odds ratio (OR) of discriminating hemorrhagic from non-hemorrhagic stroke with DNA was 4.24 (95% CI 1.88-9.56); S100 and DNA together give an OR of 16.55. CONCLUSION: For stroke diagnosis, S100 performs better than DNA; DNA is a better marker for hemorrhage. For diagnosis of hemorrhagic stroke, combined S100 and DNA performs better than either alone. Plasma DNA and serum S100 predict morbidity and mortality in stroke.

Adult↗
PubMed2006

Plasma beta-globin DNA as a prognostic marker in chest pain patients.

BACKGROUND: Acute coronary syndrome may involve cell death and the release of nucleic acids into the circulation. We thus investigated whether plasma DNA concentrations are increased and determined its prognostic significance in patients with ACS. METHODS: Real-time polymerase chain reaction was used to quantitatively measure the beta-globin gene from blood samples taken from patients presenting to an emergency department with chest pain of probable cardiac cause. RESULTS: Samples from 58 patients with chest pain, and from 21 age- and sex-matched healthy control subjects were analysed. Compared with the control group, median plasma DNA concentrations were increased 1.5-fold in patients with minor cardiac injury, were increased further in patients with STEA and STEMI, and were the highest in those patients who died within 2 years (P=0.0005; post-hoc Dunn's, P<0.05). Median plasma DNA concentrations were higher in patients who later developed heart failure (1060 vs. 500 kGE/l; P=0.0095); higher in patients who later reinfarcted (1000 vs. 530 kGE/l; P=0.0298); higher in patients who had a cardiac arrest in that admission (1350 vs. 525 kGE/l; P=0.04); and were higher in patients who were readmitted within 6 months of discharge (725 vs. 475 kGE/l; P=0.04). CONCLUSION: Plasma DNA is a potential marker for post-ACS complications.

Adult↗
PubMed2006

Circulating nucleic acids and critical illness.

This article reviews some of the early work that has been performed to investigate the potential roles of circulating nucleic acids as prediction markers in acute illness and injury. Circulating DNA and RNA concentrations are elevated early in patients with trauma, stroke and ACS, and are generally highest in patients with a high risk of death. Circulating nucleic acids may be useful markers for the evaluation and risk-stratification of such patients.

Biomarkers↗
PubMed2003

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. The primary outcome measures were in-hospital and 6-month mortality and morbidity using the post-stroke modified Rankin Score. RESULTS: Among the 88 consecutive patients recruited to the study, 70 (80%) had ischemic stroke, 11 (13%) had intracerebral hemorrhage, and 7 (8%) had transient ischemic attacks. Median plasma DNA concentrations taken within 3 h of symptom onset were higher in patients who died compared with those who survived at discharge (6205 vs 1334 kilogenome-equivalents/L; P = 0.03). Among patients with NIH Stroke Scale scores >8, median plasma DNA concentrations were higher in patients who died compared with those who survived to 6 months (2273 vs 968 kilogenome-equivalents/L; P = 0.002). Plasma DNA concentrations correlated with the volume of cerebral hematoma (r = 0.66; P = 0.03). Plasma DNA concentrations >1400 kilogenome-equivalents/L had a sensitivity of 100% and a specificity of 74.4% for predicting hospital mortality after stroke, and the area under the ROC curve was 0.89 (95% confidence interval, 0.80-0.94). The adjusted odds ratio for plasma DNA concentrations predicting 6-month mortality was 1.6 (1.1-2.4; P = 0.03) and for predicting 6-month post-Rankin Score >2 was 1.8 (1.0-3.3; P = 0.05). CONCLUSION: Plasma DNA concentrations correlate with stroke severity and may be used to predict mortality and morbidity in the emergency room.

Acute Disease↗
PubMed2003

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. The concentrations and physical characteristics of circulating mitochondrial DNA were investigated by experiments conducted in three modules. In module 1, we evaluated the concentrations of mitochondrial DNA in plasma aliquots derived from four blood-processing protocols. In module 2, we investigated the existence of both particle-associated and free forms of mitochondrial DNA in plasma by subjecting plasma to filtration and ultracentrifugation. In module 3, we used filters with different pore sizes to investigate the size characteristics of the particle-associated fraction of circulating mitochondrial DNA. RESULTS: The mitochondrial DNA-specific, real-time quantitative PCR had a dynamic range of five orders of magnitude and a sensitivity that enabled detection of one copy of mitochondrial DNA in plasma. In module 1, we found significant differences in the amounts of circulating mitochondrial DNA among plasma aliquots processed by different methods. Data from module 2 revealed that a significant fraction of mitochondrial DNA in plasma was filterable or pelletable by ultracentrifugation. Module 3 demonstrated that filters with different pore sizes removed mitochondrial DNA from plasma to different degrees. CONCLUSIONS: Both particle-associated and free mitochondrial DNA are present in plasma, and their respective concentrations are affected by the process used to harvest plasma from whole blood. These results may have implications in the design of future studies on circulating mitochondrial DNA measured in different disease conditions.

Blood Circulation↗
PubMed2003

Time course of early and late changes in plasma DNA in trauma patients.

BACKGROUND: Cell-free DNA concentrations increase in the circulation of patients after trauma and may have prognostic potential, but little is know concerning the temporal changes or clearance of the DNA or its relationships with posttraumatic complications. We investigated temporal changes in plasma DNA concentrations in patients after trauma with use of real-time quantitative PCR. METHODS: Serial plasma samples were taken from two trauma populations. In the first study, samples were collected every 20 min from 25 patients within the first 3 h of trauma. In the second study, samples were collected every day from 36 other trauma patients admitted to the intensive care unit (ICU). RESULTS: In the first study, plasma DNA was increased within 20 min of injury and was significantly higher in patients with severe injury and in patients who went on to develop organ failure. In patients with less severe injuries, plasma DNA concentrations decreased toward reference values within 3 h. In the second study, plasma DNA concentrations were higher in patients who developed multiple organ dysfunction syndrome between the second and fourth days of admission than in patients who did not develop the syndrome. In patients who remained in the ICU with continuing organ dysfunction, plasma DNA remained higher than in healthy controls even at 28 days after injury. Most survivors with multiple organ dysfunction syndrome showed an initial very high peak followed by a prolonged smaller increase. CONCLUSIONS: Plasma DNA concentrations increase early after injury and are higher in patients with severe injuries and in those who develop organ failure. Increased plasma DNA persists for days after injuries, especially in patients with multiple organ dysfunction syndrome.

Adult↗
PubMed2002

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 0.22 microm) and ultracentrifugation. We assessed plasma RNA content by a real-time quantitative reverse transcription-PCR assay for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts and plasma DNA by a real-time quantitative PCR assay for the beta-globin gene. RESULTS: The plasma GAPDH mRNA concentrations in the healthy individuals were significantly different in every pair of these filter sizes (P <0.05 for each pair). Overall, the plasma GAPDH mRNA concentration was higher by a median of 15-fold (interquartile range, 10- to 24-fold) in the paired unfiltered sample than in the sample filtered through a 0.22 microm filter. In contrast, no significant difference was seen in beta-globin DNA concentrations among different pore-size-filtered plasma samples (P = 0.455). Similarly, a significant difference was observed for RNA, but not DNA, between unfiltered plasma and ultracentrifuged plasma (P <0.05). No significant difference in GAPDH mRNA concentrations was seen between the 0.22-microm-filtered plasma samples and the ultracentrifuged plasma samples (P >0.05). In HCC patients, filtration with a 0.22 microm filter produced a median 9.3-fold (interquartile range, 6.9- to 311-fold) reduction in GAPDH mRNA concentration in plasma. Plasma GAPDH mRNA concentrations in HCC patients were significantly higher than those in healthy individuals, both with or without filtration (P <0.0 5 for filtered plasma samples; P <0.005 for unfiltered plasma samples). CONCLUSIONS: A substantial proportion of plasma mRNA species is particle-associated. In HCC patients, both circulating particle- and non-particle-associated plasma RNA are increased.

Carcinoma, Hepatocellular↗