A novel approach to stable superhydrophobic surfaces.
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Journal Article↗
Biomedical subjects
Wei-min Liu
Publications and source records attributed to Wei-min Liu.
PQN and DQN: algorithms for expression microarrays.
An ideal expression algorithm should be able to tell truly different expression levels with small false positive errors and be robust to assay changes. We propose two algorithms. PQN is the non-central trimmed mean of perfect match intensities with quantile normalization. DQN is the non-central trimmed mean of differences between perfect match and mismatch intensities with quantile normalization. The quantiles for normalization can be either empirical or theoretical. When array types and/or assay change in a study, the normalization to common quantiles at the probe set level is essential. We compared DQN, PQN, RMA, GCRMA, DCHIP, PLIER and MAS5 for the Affymetrix Latin square data and our data of two sets of experiments using the same bone marrow but different types of microarrays and different assay. We found the computation for AUC of ROC at affycomp.biostat.jhsph.edu can be improved.
Algorithms↗
Role of sonic hedgehog in maintaining a pool of proliferating stem cells in the human fetal epidermis.
BACKGROUND: The mammalian epidermis is maintained by the ongoing proliferation of a subpopulation of keratinocytes known as epidermal stem cells. Sonic hedgehog (Shh) can regulate morphogenesis of hair follicles and several types of skin cancer, but the effect of Shh on proliferation of human putative epidermal stem cells (HPESCs) is poorly understood. METHODS AND RESULTS: We first found that Shh, its receptors Patched1 (Ptc1) as well as Smoothened (Smo) and its downstream transcription factor Gli-1 were expressed in the basal layer of human fetal epidermis and freshly sorted HPESCs. Next, treatment of HPESCs with media conditioned by Shh-N-expressing cells promoted cell proliferation, whereas inhibition of Shh by cyclopamine, a specific inhibitor of Shh signalling, had an opposite effect. Interestingly, the mitogenic effect of epidermal growth factor (EGF) on HPESCs was efficiently abolished by cyclopamine. Finally, bone morphogenetic protein 4 (BMP-4), a potential downstream effector of Shh signalling, increased HPESC proliferation in a concentration-dependent manner. CONCLUSIONS: Shh is an important regulator of HPESC proliferation in the basal layer of human fetal epidermis and modulates the cell responsiveness to EGF, which will assist to unravel the mechanisms that regulate stem cell proliferation and neoplasia in the human epidermis.
Bone Morphogenetic Protein 4↗
Randomized double-blinded and controlled clinical trial on treatment of HIV/AIDS by Zhongyan-4.
OBJECTIVE: To assess the efficacy and safety of Zhongyan-4 (ZY-4, a Chinese herbal preparation worked out according to the therapeutic principle of supplementing qi, nourishing Yin, clearing heat and detoxication) in treating HIV/AIDS patients in the early or middle stage. METHODS: Adopted was randomized double-blinded and placebo-parallel-controlled method, with 72 HIV/AIDS patients randomly divided into the ZY-4 group (36 patients) treated with ZY-4 and the control group (36 patients) treated with placebo. The treatment course was six months. The index of CD(4)(+), CD(8)(+) counts, body weight, clinical symptom scoring were estimated at 4 time points (0, 1, 3 and 6 month in the course), and also the viral load before and after treatment. The whole course of observation was completed in 63 patients, 30 in the ZY-4 group and 33 in the control group. RESULTS: CD(4)(+) count in the ZY-4 group got elevated by 7.70 +/- 150.96/mm(3) on average, while that in the control group lowered by 27.33 +/- 85.28/mm(3). Fifteen out of the 30 patients in the ZY-4 group had their CD(4)(+) count increased, which was evidently much higher than that in the control group (8/33, P < 0.05), suggesting that the efficacy of ZY-4 is superior to that of placebo in elevating CD(4)(+) count. Moreover, ZY-4 showed actions in elevating CD(45)RA(+) and CD(8)(+) count, reducing HIV virus load, improving clinical symptom/sign and increasing body weight of patients. No obvious adverse reaction was found in the clinical trial. CONCLUSION: ZY-4 has an immunity-protective and/or rebuilding function in HIV/AIDS patients in the early and middle stage, and also shows effects in lowering viral load, increasing body weight and improving symptoms and signs to a certain degree.
Acquired Immunodeficiency Syndrome↗
[Endothelial function evaluation in salt-sensitive normotensive and mild hypertensive subjects and effects of potassium supplement].
OBJECTIVE: Salt-sensitivity plays an important role in essential hypertension and is associated with more severe target organ injury and higher mortality in patients with essential hypertension. However, the pathologic mechanism of salt-sensitivity is poorly understood and endothelial dysfunction might be involved in salt-sensitive hypertension. We, therefore, observed the endothelial function changes by measuring plasma and urine nitric oxide (NO) concentrations in salt-sensitive (SS) normotensive and mild hypertensive subjects underwent various salt loading protocols and the effects of potassium supplement. METHODS: Thirty-nine normotensive and mild hypertensive subjects (< 160/100 mm Hg), aged 16-60, were enrolled and the study protocol is as follows: 3 days baseline investigation, 1 week low-salt loading (3 g/day), 1 week. high-salt loading (18 g/day) and 1 week high-salt loading plus potassium chloride (4.5 g/day). RESULTS: Plasma and urine NO levels were significantly lower in SS (n = 8) subjects at baseline, low-salt and high-salt loading phases compared with salt-resistant subjects (SR, n = 31) and oral potassium supplement to SS subjects with high salt loading significantly increased plasma and urine NO levels. CONCLUSION: Endothelial function is impaired in normotensive and mild hypertensive SS subjects. Oral potassium supplement could improve endothelial function in normotensive and mild hypertensive SS subjects.
Adult↗
[Effect of glucocorticoid with traditional Chinese medicine in severe acute aespiratory syndrome (SARS)].
OBJECTIVE: To evaluate the effects of traditional Chinese medicine in 461 cases of severe acute respiratory syndrome(SARS) on glucocorticoid's dosage. METHOD: By using the polycentric nonrandomized concurrent controled trial and under the condition of glucocorticoid use, the patierts were divided into two groups: the integrated traditional Chinese and western mendicine(ITCWM) and simplicity western mendicine alone(WM). The observation indexes were time in hospital, pneumonia duration, mortality, glucocorticoid's gross dosage, glucocorticoid's average dosage of days and glucocorticoid use time. RESULT: In the ITCWM group, average time in hospital was shortened (P = 0.058), pneumonia duration was shortened (P = 0.057), mortality fell (P = -0.001). The median of glucocorticoid' s gross dosage was 1,277.0 mg x d(-1) in the ITCWM group, and that was 1,680.0 mg x d(-1) in the WM group (P = 0.083). The median of glucocorticoid's average dosage of days was 84.40 mg x d(-1) in the ITCWM group, and that was 115.33 mg x d(-1) in the WM group (P = 0.025). According to the analysis of 461 cases divided by stages and different ponderance, within 7 days after illness, in the ITCWM group, the glucocorticoid' s average dosage decreased. In the common type, the dosage in the ITCWM and in the WM was 146.43 mg x d(-1), and 183.64 mg x d(-1), respectively (P = 0.057), in the severe type, that was 137.71 and 177.86 mg x d(-1), respectively (P = 0.001). CONCLUSION: Compared with the group of simplicity western mendicine, in the group of integratived Chinese and western mendicine, time in hospital shorten, pneumonia duration shorten, mortality fall, simultaneity, glucocorticoid's average dosage is decreased. The use of TCM in the forepart of treatment can be capable of decreasing glucocorticoid's dosage.
Adult↗
Enrichment and identification of human 'fetal' epidermal stem cells.
BACKGROUND: Human epidermis, a continuously renewing tissue, is maintained throughout life by stem cells that proliferate and replenish worn-out or damaged cells in the tissue. Cultured human epidermal stem cells have great potential in clinical application. However, isolating and culturing a pure population of epidermal stem cells has proven to be challenging. METHODS AND RESULTS: We show that p63, a new marker for epidermal stem cells, is expressed in the basal layer of human fetal epidermis using immunohistochemistry, and that keratinocytes with the characteristics of stem cells can be isolated from the epidermis of aborted human fetuses aged >/=20 weeks based on high expression of beta(1) integrins by fluorescence-activated cell sorting. Furthermore, the enriched population showed the expression of molecular markers of putative human epidermal stem cells under a confocal microscope and a high colony formation efficiency when it was cultured at a clonal density. Under an electron microscope the sorted stem cells exhibited a high nuclear:cytoplasmic ratio and fewer organelles than the transit amplifying cells. The cultured epidermal stem cells can also be amplified and induced to terminal differentiation by suspension in vitro. CONCLUSIONS: Human 'fetal' epidermal stem cells have been successfully isolated and cultured in vitro. The cultured human epidermal stem cells could be used as a tool for studying stem cell biology and testing stem cell therapy.
Biomarkers↗
Large-scale genotyping of complex DNA.
Genetic studies aimed at understanding the molecular basis of complex human phenotypes require the genotyping of many thousands of single-nucleotide polymorphisms (SNPs) across large numbers of individuals. Public efforts have so far identified over two million common human SNPs; however, the scoring of these SNPs is labor-intensive and requires a substantial amount of automation. Here we describe a simple but effective approach, termed whole-genome sampling analysis (WGSA), for genotyping thousands of SNPs simultaneously in a complex DNA sample without locus-specific primers or automation. Our method amplifies highly reproducible fractions of the genome across multiple DNA samples and calls genotypes at >99% accuracy. We rapidly genotyped 14,548 SNPs in three different human populations and identified a subset of them with significant allele frequency differences between groups. We also determined the ancestral allele for 8,386 SNPs by genotyping chimpanzee and gorilla DNA. WGSA is highly scaleable and enables the creation of ultrahigh density SNP maps for use in genetic studies.
Algorithms↗
[Comparative study of friction and wear behavior of different human enamel in vitro].
OBJECTIVE: To investigate the friction and wear behavior of different human enamels. METHODS: 24 enamel samples selected from aged, young permanent and faded deciduous teeth were classified into 3 groups and slid against artificial porcelain teeth in the presence of artificial saliva on an oscillating friction and wear test rig. The wear volume loss, microhardness and toughness of each group of the enamel specimens were measured, the wear scars were observed with a scanning electron microscope, and the elemental compositions of Ca, P, and Si of the wear scar and wear debris were determined with an energy dispersion spectrometer. RESULTS: The wear volume losses of aged, young permanent and deciduous tooth enamels are (2.40 +/- 1.10) x 10(-12) m(3), (3.50 +/- 1.83) x 10(-12) m(3) and (4.86 +/- 2.49) x 10(-12) m(3). The data of aged tooth enamels are statistically greater than that of deciduous tooth enamels (P < 0.05). There is no significant difference between the wear volume loss of aged and young permanent tooth enamels or between the young permanent and deciduous tooth enamels (P > 0.05). However, the friction and wear behavior of each group of enamel specimens is different from each other. CONCLUSIONS: In the present testing condition, the wear scars of each kind of enamel specimens is characterized by ploughing and cracking. The different wear resistance of the three kinds of enamels is attributed to the different microstructure of the enamel, while the hardness and toughness of the enamels are not correlated with the wear resistance.
Adolescent↗