Biomedical subjects

Z L Wang

Publications and source records attributed to Z L Wang.

At least 37 records · Page 2Linked to original sources

PubMed2003

Antisense oligonucleotide against 47-kDa heat shock protein (Hsp47) inhibits wound-induced enhancement of collagen production.

It is well known that excessive collagen synthesis during the wound-healing process causes scar formation. Our recent in-vivo study indicates that antisense treatment against 47-kDa heat shock protein (Hsp47), a collagen-specific molecular chaperone, relieves scar formation following skin wounds in rats [Wang et al., Plast. Reconstr. Surg., in press]. In order to understand the mechanism of this phenomenon, we examined the effects of antisense treatment on the expression of mRNAs and proteins of Hsp47 and collagens in fibroblasts derived from wounded rat tongues. Hsp47 and procollagen alpha1(I) and alpha1(III) mRNAs were consistently increased after wounding and were maximal at day 5 post-injury. Treatment with antisense oligonucleotide against Hsp47 efficiently blocked the production of procollagen alpha2(I) and alpha1(III) proteins, but had little effect on their mRNA levels. Therefore, we conclude that antisense oligonucleotide against Hsp47 inhibits the production of procollagen type I and III proteins in fibroblasts derived from wounded tongues, overcoming the increase in their mRNAs.

Animals↗

PubMed2003

Bilateral chylothorax following radical neck dissection.

Bilateral chylothorax as a complication of radical neck dissection is extremely rare, but it is potentially serious and sometimes fatal. We found only 14 cases reported in the English literature. Here, we report a case of bilateral chylothorax following right modified and left radical neck dissections that was successfully treated with conservative management.

Aged↗

PubMed2002

Leptin prevents the fall in plasma osteocalcin during starvation in male mice.

Plasma osteocalcin, a marker of osteoblastic activity, is reduced in starvation, malnutrition, and anorexia nervosa, resulting in low bone turnover osteoporosis. Contradictory findings about the role of leptin as a link between nutritional status and bone physiology have been reported. We demonstrate that leptin-deficient ob/ob and leptin-resistant db/db male mice have increased plasma osteocalcin, and that in male ob/ob mice osteocalcin is not decreased by starvation, unlike control mice. Intraperitoneal leptin administration increased plasma osteocalcin in male ob/ob mice, and prevented its fall during 24h fasting and 5 days of food restriction in normal male mice. This effect may be mediated via actions on the hypothalamic-pituitary-testicular or -growth hormone axes, or a direct action on osteoblasts. These studies support the hypothesis that the fall in leptin during starvation and weight loss is responsible for the associated reduction in osteoblast activity, and suggest a role for leptin in regulating bone turnover.

Animals↗

PubMed2002

Structures of oxide nanobelts and nanowires.

We have recently reported the synthesis of one-dimensional nanobelt structures of ZnO, SnO2, In2O3, CdO, Ga2O3, and PbO2 by evaporating the desired commercial metal oxide powders at high temperatures (Science (2001), 291, 1947). The as-synthesized oxide nanobelts are pure, structurally uniform, single crystalline, and most of them free from dislocations. The beltlike morphology appears to be a unique and common structural characteristic for the family of semiconducting oxides. In the present article, we focus on the twin and stacking fault planar defects found in oxide nanobelts and nanowires although they are rarely observed. Some interesting and unique growth morphologies are presented to illustrate the roles played by surface energy and kinetics in growth. It is shown that the surfaces of the oxide nanobelts are enclosed by the low-index, low-energy crystallographic facets. The growth morphology is largely dominated by the growth kinetics.

Metals↗

PubMed2002

Collagen-binding heat shock protein HSP47 expression during healing of fetal skin wounds.

Wounds in fetal animals are known to heal without scar formation, but the mechanism involved remains unclear. Scar tissue is characterized by disorganized collagen bundles. The 47-kDa heat shock protein (HSP47) is a molecular chaperone that specifically targets collagen processing. However, the role of HSP47 in scar formation is poorly understood. We studied the relation of HSP47 expression in skin to scar formation during fetal wound healing. Immunohistochemical analysis demonstrated HSP47-positive cells in the epidermal cell layer of fetal and neonatal rat skin and the absence of such cells in subcutaneous tissue. After induction of a wound on the back of fetal and neonatal rats, the message of collagen type I was increased only in neonatal skin but not in fetal skin. HSP47-positive cells consistently increased for 7 days after wound induction in neonatal rats. In contrast, HSP47-positive cells and HSP47 protein were unchanged in fetal rats. We conclude that the scarless healing of fetal skin wounds is related to lack of change in HSP47 expression. HSP47 may thus be an important determinant of scar formation during wound healing.

Animals↗

PubMed2002

Raman studies of semiconducting oxide nanobelts.

Crystalline nanobelts of ZnO and SnO2 were prepared from a thermal evaporation of oxide powders inside an alumina tube in the absence of catalysts. Typical dimensions of the nanobelt samples ranged from approximately 10 to 100 microns in length, 30 to 300 nm in width, and 6 to 30 nm in thickness. Room temperature Raman spectra were obtained on pressed mats of nanobelt samples and compared with the corresponding spectra of the starting oxide powders and bulk materials. Collectively, our Raman data indicated that the as-prepared nanobelt samples used in this study were oxygen deficient. Upon annealing at 900 degrees C in flowing oxygen for 1 h, the nanobelt samples exhibited Raman features that corresponded to those expected in respective bulk semiconducting oxides. The dimensions of the nanobelts were a bit too large to expect significant quantum size effects on the phonon structure similar to those observed in carbon nanotubes and short-period semiconductor superlattices.

Aluminum↗

PubMed2001

Nanobelts of semiconducting oxides.

Ultralong beltlike (or ribbonlike) nanostructures (so-called nanobelts) were successfully synthesized for semiconducting oxides of zinc, tin, indium, cadmium, and gallium by simply evaporating the desired commercial metal oxide powders at high temperatures. The as-synthesized oxide nanobelts are pure, structurally uniform, and single crystalline, and most of them are free from defects and dislocations. They have a rectanglelike cross section with typical widths of 30 to 300 nanometers, width-to-thickness ratios of 5 to 10, and lengths of up to a few millimeters. The beltlike morphology appears to be a distinctive and common structural characteristic for the family of semiconducting oxides with cations of different valence states and materials of distinct crystallographic structures. The nanobelts could be an ideal system for fully understanding dimensionally confined transport phenomena in functional oxides and building functional devices along individual nanobelts.

Journal Article↗

PubMed2001

A method for the fabrication of low-noise carbon fiber nanoelectrodes.

A new and facile method has been developed for the fabrication of low-noise carbon fiber microelectrodes (CFMEs) and carbon fiber nanoelectrodes (CFNEs). The carbon fiber was flame-fuse sealed in the tip of the glass capillary. The CFMEs were made by cutting the protruding carbon fiber to the desired length, and the CFNEs were achieved by etching the protruding carbon on the flame to form a nanometer-scale tip. The tip of CFNEs can be controlled within the range from 100 to 300 nm. Thus, no epoxy wax was involved in the CFMEs and CFNEs. The experimental results of inspecting CFMEs and CFNEs by scanning electron microscopy demonstrated that the surface of the electrodes and the glass/fiber interface are very smooth. Therefore, the noise caused by the glass/fiber of these electrodes is much lower than that of the electrodes fabricated conventionlly. The electrodes were characterized by ferricyanide, catecholamine (dopamine,DA), norepinephrine (NE), and epinephrine (E)) and 5-hydroxytryptamine (5-HT) neurotransmitters using CV, LSV, DPV, and FSCV. The results showed that the CFMEs and CFNEs have very excellent electrochemical behavior and high sensitivity. The CV and DPV detection limits of DA, NE, and E are 7.6 x 10(-8), 7.0 x 10(-8), and 5.0 x 10(-8) mol/L, and the DPV detection limits of DA, NE, and E are 4.0 x 10(-8), 1.0 x 10(-7), and 2.2 x 10(-7) mol/L, respectively. This experiment offers a new and facile method for the fabrication of CFMEs and CFNEs of very high sensitivity and low noise.

Carbon↗

PubMed2001

Selenium, iodine and fungal contamination in Yulin District (People's Republic of China) endemic for Kashin-Beck disease.

We studied the status of selenium, iodine and fungal contamination in 353 school children (age 5-14 years) from four rural villages in the District of Yulin. In three villages Kashin-Beck disease (KBD) was endemic, whereas there were no cases of KBD in the fourth village. Clinical, biological and radiological examinations (right hand) were performed and KBD was established by X-ray diagnosis. The prevalence rate of KBD was 30.2%, 44.2% and 45.3% in the three endemic villages. Mean hair selenium and urine iodine concentrations were lower in affected than in unaffected children and fungal contamination in cereal grains stored in families with KBD was more elevated than in families without KBD. Low hair selenium concentration and presence of fungal cereal contamination were significantly associated with an increased risk of KBD, but low urine iodine was not.

Adolescent↗

PubMed2001

Synthesis, crystal structure and properties of a new dinuclear manganese(III) complex: a mimic for catalase.

A new dinuclear manganese (III) complex [(ac)Mn(bbml)(2)Mn(ac)] x (BF(4))(2) x 3.5H(2)O (Hbbml=[bis(2-benzimidazolylmethyl)amino]ethanol, Hac=acetic acid) was synthesized and characterized by several physical methods. X-ray structure analysis shows that the complex has a dimeric unit and the two Mn(III) atoms are bridged by the oxygen atoms of the two ligands, forming a bis (micro-alkoxo)dimanganese core. The Mn-Mn distance is 3.2103 A. Electrospray mass spectrometry (ES-MS) experiment shows that the complex cation may easily have lost one or two ac(-) and leave unoccupied coordination site which would favor the coordination and activation of hydrogen peroxide. Furthermore, its catalytic activity for the disproportionation of hydrogen peroxide and the effect of added heterocyclic base were also investigated. The complex has some similarities to manganese catalase in structure and activity.

Binding Sites↗

PubMed2001

Pathological changes in human malignant carcinoma treated with high-intensity focused ultrasound.

The purpose of this study was to investigate the pathologic changes of extracorporeal ablation of human malignant tumors with high-intensity focused ultrasound (HIFU). HIFU treatment was performed in the 164 patients with liver cancer, breast cancer, malignant bone tumor, soft tissue sarcoma and other malignant tumors at focal peak intensities from 5000 W x cm(-2) to 20,000 W x cm(-2), with operating frequencies of 0.8 to 3.2 MHz. To explore the pathologic impact of extracorporeal HIFU, 30 patients with malignant carcinoma underwent surgical removal after HIFU treatment. Pathologic findings showed that the treated tissues demonstrated homogeneous coagulative necrosis with an irreversible tumor cell death and severe damage to tumor blood vessels at the level of microsvasculature within the HIFU-targeted region. Thermolesions to intervening tissue were never observed. The treated region had a sharp border comprising only several cell layers between the treated and untreated areas. The repair of lesions had the processes of necrotic tissue absorption and granulation tissue replacement. It is concluded that extracorporeal treatment of human solid malignancies with HIFU could be safe, effective and feasible. As a noninvasive therapy, HIFU would be used clinically to treat patients with solid malignancies.

Bone Neoplasms↗

PubMed2001

[Molecular identification and mapping of a maize gene (Rf3) in S-type CMS using AFLP, RFLP and SCAR techniques].

The maize CMS-S near isogenic line (NIL) developed by author and the backcross progeny (BC1) derived from it were used to identify molecular markers linked to the Rf3 gene and subsequently determine its chromosomal location on the linkage map of maize. Bulk segreant analysis was performed using AFLP technique. From the survey of AFLP primer combination, two AFLP markers, (EcoRI-AGG/MseI-CAC and EcoRI-AAC/MseI-CAG), which were named RR6 and RR7 respectively, linked to the Rf3 gene were identified. However, AFLP marker RR6 showed polymorphism between parents, and bulks were used to survey the available 100 individuals of the BC1 population, 2 out of 100 shed recombination. The recombination-rate was 2%. The genetic distance between Rf3 gene and AFLP marker RR6, was approximately 2.0 cM. And then, the RR6 was successfully cloned and sequenced, primer synthesized and converted to SCAR marker so that PCR marker can be developed for the marker-assisted selection. In RFLP analysis, marker RR6 linked to Rf3 was found to be located between RFLP loci asg20 and php20581b, and mapped on chromosome 2L.

Chromosome Mapping↗

PubMed2001

[Effect of mm-LDL on NF-kB activation in endothelial cell].

OBJECTIVE: To investigate the signal transduction pathway of NF-kB activated by minimally modified low density lipoprotein (mm-LDL) in endothelial cells and the effect of NF-kB on platelet derived growth factor b (PDGFb) mRNA expression. METHODS: mm-LDL was prepared through iron oxidation by dialyzing the native LDL against FeSO4 in PBS. Endothelial cells were incubated in a medium containing mm-LDL, TNF, and IL-1 respectively and electrophoretic mobility shift assay (EMSA) was displayed to check on the activation of NF-kB. Luciferase reporter gene was analysed to investigate the effect of nuclear factor inducing kinase (NIK), inhibitor of NF-kB kinase alpha (IKK alpha) and inhibitor of NF-kB kinase beta (IKK beta) on NF-kB activation. In addition, endothelial cells were transfected using PDGFb promoter-luciferase for reporter gene analysis or transfected with mut-NIK for slot blot analysis to study the effect of NF-kB on PDGFb mRNA expression. RESULTS: mm-LDL was able to activate NF-kB in endothelial cells. mut-NIK and mut-IKK beta inhibited luciferase activity induced by mm-LDL. mm-LDL could also enhance luciferase activity controlled by upstream sequence of PDGFb promoter which contains element interacting with NF-kB. Result of slot blot showed inhibition of PDGFb mRNA expression by mut-NIK in the endothelial cells stimulated by mm-LDL. CONCLUSION: mm-LDL may activate NF-kB through NIK-IKK beta pathway and promote PDGFb mRNA expression in endothelial cells.

Cells, Cultured↗

PubMed2001

[Effect of oxLDL on the uptake and clearance rate of cholesterol in vascular smooth muscle cells originated from human apoAI transgenic mice].

OBJECTIVE: Study on (1) inhibition of oxidized low density lipoprotein (oxLDL) effect on the uptake and clearance of intra-cellular 3H-cholesterol in vascular smooth muscle cells (v-SMC) originated from the human-apoAI transgenic mice (C57BL/6); (2) change of human-apolipoprotein AI (h-apoAI) mRNA expression in v-SMC after oxLDL stimulation and the protective effect of expressed h-apoAI on v-SMC against oxLDL intoxication. METHODS: (1) v-SMC isolated from human apoAI transgenic mice possessing a recombined gene connected beforehand with a mouse metallothionein-I (MT-I) as the promoter; (2) study of h-apoAI mRNA expression from v-SMC of the transgenic mice by RT-PCR and Northern blot. RESULTS: oxLDL (30 micrograms/ml) strongly promoted v-SMC proliferation. No difference found on 3H-cholesterol uptake between smooth muscle from normal mouse aorta (n-SMC) and smooth muscle cells from transgenic mouse aorta (tr-SMC) of the control groups, the uptake rates of both kinds of SMC rose 100% after oxLDL stimulation. The efflux rates of 3H-cholesterol in tr-SMC were much higher than those of n-SMC (40%-50%). After oxLDL stimulation, the clearance rates fell by 28% and 10% respectively for n-SMC and tr-SMC. The result of RT-PCR and Northern blot showed a marked increase of h-apoAI gene expression after oxLDL stimulation. CONCLUSIONS: Expression of h-apoAI gene in C57BL/6 mice enables to decrease the accumulation of cholesterol in v-SMC. tr-SMC are capable to alleviate the harmful effect of oxLDL on v-SMC due to the increase of h-apoAI expression.

Animals↗

PubMed2000

Competition and coexistence in spatially subdivided habitats.

While non-spatial models predict that like species cannot stably coexist, empirical studies suggest that similar species have similar distributions due to shared habitat requirements. A model is developed to discuss competition and coexistence in subdivided but locally stable habitats. The model predicts that in some cases it is possible for one species to exclude the other species from a geographic region, while in other cases two competing species can stably coexist. The equilibrium level and the fraction of doubly occupied patches, if there is coexistence, are determined by the strength of competition on colonization and exclusion in such a system. Also, it is possible for two ecologically identical species to stably coexist, and two asymmetrically competing species can coexist when there is a trade-off between local competition ability and invasion ability. When rescue effects are considered, the stable region at internal equilibrium point would be reduced, but the fraction of doubly occupied patches would be enlarged.

Animals↗

PubMed2000

Nanomechanics of individual carbon nanotubes from pyrolytically grown arrays.

The bending modulus of individual carbon nanotubes from aligned arrays grown by pyrolysis was measured by in situ electromechanical resonance in transmission electron microscopy (TEM). The bending modulus of nanotubes with point defects was approximately 30 GPa and that of nanotubes with volume defect was 2-3 GPa. The time-decay constant of nanotube resonance in a vacuum of 10(-4) Torr was approximately 85 micros. A femtogram nanobalance was demonstrated based on nanotube resonance; it has the potential for measuring the mass of chain-structured large molecules. The in situ TEM provides a powerful approach towards nanomechanics of fiberlike nanomaterials with well-characterized defect structures.

Journal Article↗

PubMed2000

Endothelial nitric oxide synthase protects aortic allografts from the development of transplant arteriosclerosis.

BACKGROUND: Inducible nitric oxide synthase (iNOS) is up-regulated in rejecting allografts and is protective against allograft arteriosclerosis; it suppresses neointimal smooth muscle cell accumulation and inhibits adhesion of platelets and leukocytes to the endothelium. However, the functional importance of endothelial NOS (eNOS) in the rejecting allografts remains unclear. METHODS: We examined the effects of selective eNOS deficiency in aortic allografts in a murine chronic rejection model using grafts from eNOS knockout (KO) mice (C57BL/6 background; H2b) and normal C3H (H2K) as recipients. Grafts from wild-type C57BL/6 mice served as controls. Grafts from iNOS KO mice served as a second group of controls where the contribution from iNOS was eliminated but eNOS was preserved. Aortic grafts were harvested and analyzed at days 10-14, 18-22, and 26-30 after transplantation. RESULTS: Endothelial NOS-deficient grafts showed significantly increased intima/media ratios at days 26-30 compared to controls. Immunostaining demonstrated that in eNOS KO grafts, eNOS was not detectable whereas iNOS was expressed prominently in infiltrating recipient mononuclear cells. In control grafts, eNOS expression was preserved in the endothelium even by day 30, and associated with a decrease in intimal thickening. We further demonstrated that early overexpression of iNOS by ex vivo gene transfer completely prevented the development of arteriosclerosis associated with eNOS deficiency. CONCLUSIONS: We found that eNOS plays a protective role in allografts, and that in eNOS-deficient allografts, early overexpression of iNOS is capable of preventing the development of allograft arteriosclerosis. In allografts with dysfunctional vascular endothelium and impaired eNOS activity as a result of ischemia or native arteriosclerotic disease, iNOS gene therapy may serve to improve their long-term survival and function.

Animals↗

PubMed2000

Enhancement of the photodynamic antitumor effect by streptococcal preparation OK-432 in the mouse carcinoma.

Biological response modifier antitumor effects are enhanced by the activation of the host defense mechanisms. We have investigated the antitumor effect of photodynamic therapy (PDT) and/or local administration of a biological response modifier, the streptococcal preparation OK-432, on transplanted NR-S1 mouse squamous cell carcinoma. Hematoporphyrin oligomers (20 mg/kg body weight) were used to photosensitize PDT. A pulsed Nd:YAG dye laser, tuned at 630 nm, was used as the light source. The laser power was 15 mJ cm(-2) pulse(-1), and the irradiation time was 40 min. The photosensitizer was injected intraperitoneally 48 h before laser irradiation. Where used, OK-432 was injected into the tumor either 3 h prior to PDT or immediately afterwards. The antitumor effects were evaluated 48 h after each protocol by (a) estimating the area of tumor necrosis (%) in hematoxylin/eosin-stained specimens, and (b) bromodeoxyuridine immunohistochemistry. Furthermore, the tumor sizes were evaluated 3, 7 and 10 days after each protocol, and the survival time after each protocol was evaluated as well. The antitumor effect of PDT was enhanced by administration of OK-432 3 h before PDT, whereas the administration of OK-432 immediately after PDT did not potentiate a PDT antitumor effect. Treatment with OK-432 alone had little effect on tumors. Photodynamic therapy in combination with local administration of OK-432 3 h before PDT is considered to be a useful treatment modality.

Animals↗