PubMed Health⌕ Search

Biomedical subjects

Min Hu

Publications and source records attributed to Min Hu.

At least 55 records · Page 3Linked to original sources
PubMed2005

Time-resolved and steady state spectroscopy of polydisperse colloidal silver nanoparticle samples.

A signal due to coherently excited vibrational motion has been observed in polydisperse silver nanoparticle samples. The particles were synthesized via a wet chemistry seed mediated method, which yields different particle shapes, including spheres, rods, and irregular triangular-shaped particles. The measured vibrational periods were compared to the results from continuum mechanics calculations. This analysis shows that the observed signal arises from the triangular-shaped particles, rather than the rods or spheres. The period of vibration increases as the dimensions of the triangular-shaped particles increase; specifically, we find that the period is given by 2h/c(l), where h is the bisector of the triangle and c(l) is the longitudinal speed of sound in silver.

Colloids↗
PubMed2005

Seasonal pollution characteristics of organic compounds in atmospheric fine particles in Beijing.

Beijing is a rapidly developing city with severe and unique air pollution problems. Organic matter is the most abundant fraction in fine particles in Beijing, occupying 30-50% of the total mass, indicating its key role in air pollution control. However, detailed chemical characterization of particulate organic matter in Beijing has never been reported. In this study, fine particles in the urban atmosphere in Beijing were investigated for its organic components by GC/MS technique. Over 100 individual organic compounds were identified and quantified in 25 PM2.5 samples from the summer, autumn and winter of 2002-2003. Alkanes, fatty acids, dicarboxylic acids, polycyclic aromatic hydrocarbons and some important tracer compounds (hopanes, levoglucosan and steroids) were the major constituents with the sum of their concentrations of 502, 1471 and 1403 ng m(-3) in summer, autumn and winter, respectively. Different organic compounds presented apparently different seasonal characteristics, reflecting their different dominant emission sources, such as coal combustion, biomass burning and cooking emission. The abundance and origin of these organic compounds are discussed to reveal seasonal air pollution characteristics of Beijing.

Air Pollutants↗
PubMed2005

Multicystic dysplastic kidney and variable phenotype in a family with a novel deletion mutation of PAX2.

The renal coloboma syndrome (OMIM 120330) is caused by mutations in the PAX2 gene. Typical findings in these patients include renal hypoplasia, renal insufficiency, vesicoureteric reflux, and optic disc coloboma. A family with a novel heterozygous 10-bp deletion in exon 2 of the PAX2 gene leading to a truncating mutation and variable phenotype across three generations is reported. The first presentation of multicystic dysplastic kidney in this syndrome is reported. The possibility that abnormal PAX2 protein in this case may cause a dominant negative effect also is discussed. The finding of multicystic dysplastic kidney in renal coloboma syndrome could suggest that PAX2 may play a role in early ureteric obstruction and subsequent renal maldevelopment.

Adult↗
PubMed2005

Distinct epigenetic changes in the stromal cells of breast cancers.

Increasing evidence suggests that changes in the cellular microenvironment contribute to tumorigenesis, but the molecular basis of these alterations is not well understood. Although epigenetic modifications of the neoplastic cells in tumors have been firmly implicated in tumorigenesis, it is not known whether epigenetic modifications occur in the non-neoplastic stromal cells. To address this question in an unbiased and genome-wide manner, we developed a new method, methylation-specific digital karyotyping, and applied it to epithelial and myoepithelial cells, stromal fibroblasts from normal breast tissue, and in situ and invasive breast carcinomas. Our analyses showed that distinct epigenetic alterations occur in all three cell types during breast tumorigenesis in a tumor stage- and cell type-specific manner, suggesting that epigenetic changes have a role in the maintenance of the abnormal cellular microenvironment in breast cancer.

Breast Neoplasms↗
PubMed2005

Polymerase chain reaction of nanoparticle-bound primers.

Using one or two primers respectively bound to the surface of Au nanoparticles (AuNPs) or magnetic nanoparticles (MNPs), polymerase chain reaction (PCR) based on nanoparticles was systemically studied, agarose gel electrophoresis and atomic force microscopy (AFM) were respectively used to detect and observe the PCR product. The results obtained indicated that with either one or two primers respectively bound to the nanoparticle surface, PCR can proceed successfully under optimized condition and is subject to certain rules, consequently a symmetric PCR technique and an asymmetric PCR technique based on nanoparticles have been developed. A kind of nanostructured aggregates can be constructed by a symmetric PCR using two nanoparticle-bound primers.

Base Sequence↗
PubMed2005

When aerosol sulfate goes up, so does oxalate: implication for the formation mechanisms of oxalate.

Oxalic acid is often the single most abundant water-soluble organic compound identified in ambient aerosols, but its precursors have not been identified, and its formation mechanism is not well understood. On the contrary, sulfate as a major aerosol component, its formation pathways have been established, and in-cloud processing is recognized as its major production pathway. Our measurements of aerosol sulfate and oxalate collected across a wide geographical span in the East Asia region, up to Beijing in the north and down to Hong Kong in the south, indicate that the two species are highly correlated among samples collected at the same location and among samples collected at different locations in the Pearl River Delta region. This good correlation is also found in measurements made elsewhere by other researchers. We argue that a common dominant formation pathway, likely in-cloud processing, explains the close tracking of the two chemically distinct species. This also highlights the potential importance of in-cloud processing as a pathway leading to formation of secondary organic aerosols.

Aerosols↗
PubMed2005

Mutation scanning-coupled analysis of haplotypic variability in mitochondrial DNA regions reveals low gene flow between human and porcine Ascaris in endemic regions of China.

Haplotypic variation within and among the Ascaris populations representing six provinces in China was investigated. Mitochondrial DNA regions in the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes were amplified by PCR from total genomic DNA samples (n > 720) from Ascaris individuals from humans and pigs, and subjected to mutation scanning and subsequent selective sequencing. For the cox1, ten different electrophoretic profiles were recorded for human Ascaris, and the same number for pig Ascaris, one of them being common to both host species. For the nad1, 11 different profiles were detected for human Ascaris, and 15 for pig Ascaris. Having defined all haplotypes (20 for pcox1 and 26 for pnad1) by sequencing, their frequencies were estimated in each of the two host species and each of the six provinces. For each mitochondrial region, the frequency of the different haplotypes varied considerably, depending on host species and geographical origin. Analysis of the sequence data (representing all haplotypes for each mitochondrial locus) by F-statistics indicated restricted gene flow between human Ascaris and pig Ascaris, and supported the conclusions from previous molecular epidemiological investigations that pigs are not a significant source of Ascaris infection in humans in endemic regions.

Animals↗
PubMed2005

Clinical study on effect of Osteoking in preventing postoperational deep venous thrombosis in patients with intertrochanteric fracture.

OBJECTIVE: To evaluate the effect of Osteoking ( masculine(1)i) in preventing postoperational deep venous thrombosis (DVT) in patients with intertrochanteric fracture (ITF). METHODS: With prospective and randomized controlled clinical design adopted, 62 patients with ITF after operation were assigned into 2 groups, the tested group and the control group, Osteoking (25 ml every other day) and Sanchi-dansheng tablets (3 tablets thrice a day) were given orally to them respectively for 10 days. Difference of round length of thighs and shanks between two sides were measured on the 10th day and Doppler ultrasonic examination on the fractured leg was carried out. RESULTS: The occurrence rate of DVT in the tested group was 9.4%, which was lower than that in the control group (30.0%, P < 0.05). All the difference of round lengths, either that of the thigh or the shank, was less in the tested group than that in the control group, showing statistical significance (P < 0.05). CONCLUSION: Osteoking has a satisfactory effect in preventing postoperational DVT in patients with ITF.

Administration, Oral↗
PubMed2005

Do myoepithelial cells hold the key for breast tumor progression?

Mammary myoepithelial cells have been a neglected facet of breast cancer biology, largely ignored since they have been considered to be less important for tumorigenesis than luminal epithelial cells from which most of breast carcinomas are thought to arise. In recent years as our knowledge of stem cell biology and the cellular microenvironment has been increasing, myoepithelial cells are slowly starting to gain more attention. Emerging data raise the hypothesis whether myoepithelial cells play a key role in breast tumor progression by regulating the in situ to invasive carcinoma transition and that myoepithelial cells are part of the mammary stem cell niche. Paracrine interactions between myoepithelial and luminal epithelial cells are known to be important for regulation of cell cycle progression, establishing epithelial cell polarity, and inhibiting cell migration and invasion. Based on these functions, normal mammary myoepithelial cells have been called "natural tumor suppressors." However, during tumor progression myoepithelial cells seem to loose these properties, and eventually this cell population diminishes as tumors become invasive. Better understanding of myoepithelial cell function and their role in tumor progression may lead to their exploitation for cancer therapeutic and preventative measures.

Breast Neoplasms↗
PubMed2005

Impact of meteorology and energy structure on solvent extractable organic compounds of PM2.5 in Beijing, China.

Twenty-eight PM2.5 samples collected in Summer (July 2002) and Winter (November 2002) at two sites in Beijing, China were analyzed using GC/MS to investigate the impact of meteorology and coal burning on the solvent extractable organic compounds (SEOC). The characteristics and abundance of the n-alkanes, polycyclic aromatic hydrocarbons (PAHs), n-fatty acids and n-alkanols were determined. Source identification was made using organic species as molecular markers. Semi-volatile compounds of alkanes and PAHs had much higher concentrations in winter than summer because of the large difference in the temperature between the seasons. Plant wax emission was a major contributor to n-alkanes in summer, but fossil fuel residue was a major source (>80%) in winter. The seasonal differences in the distribution of pentacyclic triterpanes clearly shows the impact of coal burning for space heating in winter. The yield of PAHs in winter (148 ng m(-3) at the urban site and 277 ng m(-3) at the suburban site) was six to eight times higher than that in summer and was found to be mainly from coal burning. Higher pollutant concentrations were measured at the suburban site than the urban site in winter due to the rapid expansion of the city limit and the relocation of factories from urban to suburban areas over the last two decades.

Aerosols↗
PubMed2005

Study on modification of collagen with chondroitin sulfate on the microcosmic level.

To observe the changes during the process of modificating collagen with chondroitin sulfate (CS), a series of experiments was designed. Collagen scaffold was constructed by lyophilization. CS was attached into the scaffold through crosslinking. Solid-liquid phase separation method was used to shape 3D porous structure. Both kinds of scaffolds were investigated by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Electron Spectroscopy for Chemical Analysis (ESCA), Amino Acid Analyses (AAA), and so on for structures and characteristics. The results showed that CS could improve the properties of collagen both in biocompatibility and mechanical property. It increased the polar groups on the surface of scaffold and protected amino acid residues of collagen fiber. At the same time, the structure of scaffold became more regular because of the increase of polar groups. It was indicated that those were the real reasons for the improvement of modification.

Amino Acids↗
PubMed2005

LIF and BMP signaling generate separate and discrete types of GFAP-expressing cells.

Bone morphogenetic protein (BMP) and leukemia inhibitory factor (LIF) signaling both promote the differentiation of neural stem/progenitor cells into glial fibrillary acidic protein (GFAP) immunoreactive cells. This study compares the cellular and molecular characteristics, and the potentiality, of GFAP(+) cells generated by these different signaling pathways. Treatment of cultured embryonic subventricular zone (SVZ) progenitor cells with LIF generates GFAP(+) cells that have a bipolar/tripolar morphology, remain in cell cycle, contain progenitor cell markers and demonstrate self-renewal with enhanced neurogenesis - characteristics that are typical of adult SVZ and subgranular zone (SGZ) stem cells/astrocytes. By contrast, BMP-induced GFAP(+) cells are stellate, exit the cell cycle, and lack progenitor traits and self-renewal--characteristics that are typical of astrocytes in the non-neurogenic adult cortex. In vivo, transgenic overexpression of BMP4 increases the number of GFAP(+) astrocytes but depletes the GFAP(+) progenitor cell pool, whereas transgenic inhibition of BMP signaling increases the size of the GFAP(+) progenitor cell pool but reduces the overall numbers of astrocytes. We conclude that LIF and BMP signaling generate different astrocytic cell types, and propose that these cells are, respectively, adult progenitor cells and mature astrocytes.

Animals↗
PubMed2005

[Effects of different TiNi-SMA distractor on the height of alveolar ridge augmentation].

OBJECTIVE: To discuss the effects of titanium nickel shape memory alloy (TiNi-SMA) distractor with different stretching force and different distance between two fixed ends on the height of alveolar ridge augmentation. METHODS: The mini distractors were all made of TiNi-SMA wire. The maximum stretching force and the distance between two fixed ends according to different distractors (A, B and C) were 20 mm, 700 g; 15 mm, 1000 g; 20 mm, 1000 g. 15 adult mongrel canines were divided into three groups randomly and extracted the mandibular premolars and first molar. One month later, box-shaped osteotomies of the alveolar bone were carried out in the left mandible and the TiNi-SMA distractors were buried. The bone height was measured and the radiographs were taken before and five weeks post operation continuously. RESULTS: One week post operation, the vertical ridge augmentation of group A, B and C averaged (7.55 +/- 1.02) mm, (4.97 +/- 0.34) mm, (8.54 +/- 0.82) mm and the height remained (7.20 +/- 1.05) mm, (4.93 +/- 0.21) mm, (8.04 +/- 0.78) mm five weeks post operation. There was no statistic difference in the height of alveolar ridge augmentation between Group A and C, but Group B showed significant difference with the other two groups. In each group, the height did not changed significantly with the time. The radiographs showed obvious distraction gap post operation, and the new bone regenerated five weeks later. CONCLUSION: It suggests that in the scope of suitable stretching force, the height of alveolar ridge augmentation was determined by the size of TiNi-SMA distractor, that is to say, determined by the distance between the two fixed ends.

Adult↗
PubMed2005

[The clinical application of acellular dermal matrix to repair the defect of oral mucosa].

OBJECTIVE: To evaluate the clinical effect of acellular dermal matrix allograft in repairing the defect of oral mucosa. METHODS: Forty-two cases of large superficial defects in oral cavity were repaired by acellular dermal matrix. Defect areas included vestibule, tongue, the floor of mouth, buccal mucosa, palate, gingival and lip. Defect size was between 2.25 cm(2) and 12 cm(2). The basement membrane side of acellular dermal matrix was exposed to oral cavity, and another side was attached to the surgical wound surface. It was fixed by suture, reverse strapping and prepared template to overlaid large superficial defect of oral mucosa. The patients were followed up from 3 months to 1 year after operation. RESULTS: The wounds were completely healed in 40 cases, partially healed in 2 cases. There was no failure case. The healing was divided into two types: epithelialization healing pattern in 12 cases, attached healing pattern in 30 cases. Contraction of grafts occurred at 2 - 4 weeks. The contraction rate was 3.7% +/- 1.1% at fourth week. Scarring did not appear. CONCLUSION: The clinical result of acellular dermal matrix allograft in repair the defect of oral mucosa is good. Acellular dermal matrix can be taken as a substitute to autograft of skin.

Adult↗
PubMed2005

[Effects of simulated weightlessness on rats mandible, lumbar vertebra and femur].

OBJECTIVE: To observe the effect of weightlessness simulation on rats mandible, lumbar vertebra and femur. METHOD: Twenty five Wistar rats were randomly arranged into control group (n=10) and tail-suspension group (n=15 rats). The experiment lasted for 28 d. Then the mandible, lumbar vertebra and femur were excised and the histological structure of condylar process of mandible, molar and premolar area of mandible body, first lumbar, head, middle segment and condyle of femur were examined. RESULT: After tail-suspension there was no distinct change in bone density and bone mass of condylar process. But the degree of interlacement of trabecular bone increased. The bone substance of mandible was very dense in both control and experimental groups. There was no stimulated difference of bone structure and bone mass between the two groups. There was no marked change in the thickness of periodontal membrane. The bone lamella in premolar area of experimental group arranged regularly. And its maturity was higher than that in molar area. The line of bone hyperplasia in molar area of experimental group arranged disorderly and irregularly, which means that much bone remodeling occurred. The component of trabecular bone decreased in femur and lumbar vertebra and the thickness was uneven. The interlacement and connection among trabecular bones was poor. CONCLUSION: Four weeks of stimulated weightlessness can lead to osteoporosis in acantha and femur [correction of feurar] but has no distinct effect on mandible.

Animals↗
PubMed2005

[Influence of vascular cell co-cultured with osteoblast in vitro on ability of osteoblast].

UNLABELLED: OBJECTIVE; The purpose of this study was to observe the influence on proliferation of rabbit osteoblast (ROB) of rabbit vascular endothelial cell(RVEC) co-cultured with rabbit osteoblast (ROB). METHODS: Rabbit osteoblasts and rabbit vascular endothelial cells in ratio of 1:0, 1:1, 2:1, 4:1 were selected to co-culture. The function of osteoblasts was assessed by alkaline phosphatase (ALP) activity and osteocalcin (OC) assay. RESULTS: There was good compatibility when osteoblasts and vascular endothelial cells were co-cultured. The activity of ALP and OC in the group of ROB and RVEC co-cultured in ratio of 2:1 was higher than that of the other three groups. CONCLUSION: In direct co-culture system in vitro, RVEC can improve activity of ROB.

Alkaline Phosphatase↗