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Biomedical subjects

W Ming

Publications and source records attributed to W Ming.

15 recordsLinked to original sources
PubMed2006

Pharmacokinetics of eprinomectin in plasma and milk following subcutaneous administration to lactating dairy cattle.

Eprinomectin is only available as a topically applied anthelmintic for dairy cattle. To determine whether eprinomectin can be applied as an injectable formulation in dairy cattle, a novel injectable formulation was developed and was subcutaneously delivered to four lactating dairy cattle at a dose rate of 0.2 mg/ kg. Plasma and milk samples were collected. The concentrations of eprinomectin in all samples were determined by HPLC. The peak plasma concentration (C(max))of 44.0+/-24.2 ng/ml occurred 39+/-19.3 h after subcutaneous administration, equivalent to the C(max) (43.76+/-18.23 ng/ml) previously reported for dairy cattle after a pour-on administration of 0.5 mg/kg eprinomectin. The area under the plasma concentration-time curve (AUC) after subcutaneous administration was 7354+/-1861 (ng h)/ml, higher than that obtained after pour-on delivery (5737.68+/-412.80 (ng h)/ml). The mean residence time (MRT) of the drug in plasma was 211+/-55.2 h. Eprinomectin was detected in the milk at the second sampling time. The concentration of drug in milk was parallel to that in plasma, with a milk to plasma ratio of 0.16+/-0.01. The highest detected concentration of eprinomectin in milk was 9.0 ng/ml, below the maximum residue limit (MRL) of eprinomectin in milk established by the Joint FAO/WHO Expert Committee on Food Additives in 2000. The amount of eprinomectin recovered in the milk during this trial was 0.39%+/-0.08% of the total administered dose. This study demonstrates that subcutaneous administration of eprinomectin led to higher bioavailability and a lower dose than a pour-on application, and that an injectable formulation of eprinomectin may be applied in dairy cattle with a zero withdrawal period.

Animals↗
PubMed2005

Controlled heterocoagulation of platelets and spheres.

We report the controlled heterocoagulation of platelets and spheres, leading to the formation of colloidally stable, anisotropic hybrid particles. Anionically charged, nanosized polymer latex spherical particles were heterocoagulated on the surface of cationically charged hexagonal gibbsite platelets via the adsorption of a single layer of spheres onto both sides of the hexagonal platelets. The latex particles were annealed at a temperature above the Tg of the latex polymer, resulting in a thin polymer layer covering the gibbsite platelets. This heterocoagulation approach enabled the encapsulation of hydrophilic inorganic particles with polymer latexes and the formation of anisotropic hybrid particles.

Journal Article↗
PubMed2005

Superhydrophobic films from raspberry-like particles.

We report a robust procedure for preparing superhydrophobic hybrid films on which the advancing contact angle for water is about 165 degrees and the roll-off angle of a 10-muL water droplet is 3 +/- 1 degrees . Dual-size surface roughness, which mimics the surface topology of self-cleaning plant leaves, originates from well-defined silica-based raspberry-like particles that are covalently bonded to an epoxy-based polymer matrix. The roughened surface is chemically modified with a layer of poly(dimethylsiloxane) (PDMS). The robustness and simplicity of this procedure may make widespread applications of so-prepared superhydrophobic films possible.

Journal Article↗
PubMed2004

The outermost atomic layer of thin films of fluorinated polymethacrylates.

In this paper, we investigate the surface properties of a series of copolymers of perfluoroalkyl methacrylate (CH2 = C(CH3)COOCH2CnF(2n + 1), n = 1, 6, or 10) and methyl methacrylate (MMA) and of blends of perfluorooctyl-end-capped poly(methyl methacrylate) (PMMA) and pure PMMA. The introduction of perfluoroalkyl groups significantly lowers the polymer surface energy as determined by the acid-base approach. X-ray photoelectron spectroscopy (XPS) confirms a higher fluorine concentration in the surface region (the outer 3.8 nm) as compared to in the bulk. The fluorine density in the outermost atomic layer is quantitatively determined by low-energy ion scattering (LEIS). A linear relationship is found between the fluorine density in the outermost atomic layer and the surface energy of the partially fluorinated polymethacrylates, irrespective of the length of the perfluoroalkyl chain. This linearity confirms Langmuir's "principle of independent surface action". Deviation from this linear relationship exists for both highly and sparsely fluorinated polymethacrylates and can be ascribed to the local (surface) ordering of the fluorinated tails and MMA units, respectively. This study may offer one further step toward a deeper understanding of the correlations between macroscopic surface properties and microscopic surface chemical composition.

Journal Article↗
PubMed2004

Quantification of fluorine density in the outermost atomic layer.

The outermost atomic layer of perfluorinated thiol monolayers on gold and poly(tetrafluoroethylene) (PTFE) is analyzed by low-energy ion scattering. Absolute quantification of fluorine density in this layer was achieved after calibrating the fluorine signal with a freshly cleaved LiF(100) single crystal. The fluorine density of monolayers of a C8F17-thiol on gold was 1.48 x 10(15) F atoms/cm2, whereas for PTFE a value of 1.24 x 1015 F atoms/cm2 was observed. This difference was explained by the different tilt angles of the thiol on gold and PTFE chains with respect to the surface normal. Both a configurational and a molecular interpretation on the perfluorinated thiol monolayer on gold are given.

Crystallization↗
PubMed2001

[The effect of p53 gene on p-glycoprotein expression and chemotherapeutic cytotoxicity of hepatocellular carcinoma].

OBJECTIVE: To test the hypothesis that wild-type p53 regulates the expression of p-glycoprotein. METHODS: Hep3B cells which lack the expression of both p53 and retinoblastoma tumor suppressor genes because of deletions, were transfected with a wild-type (wt) p53 cDNA and control vector by a liposome method. RESULTS: After G418 selection, stable wt-p53 transformants and control vector transformants (pNeo) were obtained. Northern and Western blot analysis determined the expression of p53 mRNA and protein in wt-p53 transformants, respectively. In wt-p53 transformants, induction of transcriptionally active p53 was confirmed by the increase of P21(waf1/cip1) protein. Levels of P-gp reduced in the cells expressing wild-type p53 were linked to wt-p53 activity. Cytotoxicity assays revealed that the wt-p53 transfectants were more sensitive to doxorubicin and mitomycin compared with the pNeo transformants. Flow cytometry showed that the accumulation of doxorubicin in wt-p53 transfectants was as 13 times as that of the pNeo transformants. CONCLUSIONS: Restoration of wt-p53 activity in Hep3B leads to sensitiveness to chemotherapeutic agents because of the decrease of p-glycoprotein expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Effects of acute or prolonged exposure to leptin on hepatic glucose oxidation.

OBJECTIVE: To observe the short-term and long-term effects of leptin on hepatic glucose oxidation and glucokinase gene expression. METHODS: Rat hepatic cell line BRL was incubated with leptin of different doses (range from 10 ng/ml-200 ng/ml) for 1 h or 24 h. Glucose oxidation was determined by liquid scintillation counting. Glucokinase gene expression (corrected by beta-actin) was determined by reverse transcription semi-quantitative polymerase chain reaction. RESULTS: Treatment with leptin 10 ng/ml for 1 h had no significant effects on glucose oxidation in hepatic cells. However, at the doses ranging from 50 ng/ml to 200 ng/ml, leptin significantly inhibited glucose oxidation. These effects disappeared when the hepatic cells were exposed to leptin for 24 h. Glucokinase mRNA expression was reduced significantly after both 1 h and 24 h exposure to leptin (100 ng/ml) as compared to that of the control group. CONCLUSION: A low dose of leptin has no significant effect on glucose oxidation in hepatic cells. A relatively high dose of leptin has an acute inhibitory effect on the glucose oxidation in hepatic cells. This effect may likely involve the inhibition of glucokinase gene expression. The inhibitory effect on glucose oxidation is transient and disappears with prolonged exposure time.

Animals↗
PubMed2001

[High level expression of human recombinant albumin gene in the yeast Pichia pastoris].

The yeast Pichia pastoris was transformed by the multi-copy Pichia expression vector that can express secreted human albumin. The high level expression of cell line was selected after screening. The expression of human recombinant albumin in Pichia pastoris induced by different methods were compared. The ratio of secreted human albumin is 80% in total secreted proteins and the expression level reaches as high as is 10 g/L.

Albumins↗
PubMed2000

Gene mutation in patients with primary open-angle glaucoma in a pedigree in China.

OBJECTIVE: To investigate the genetic basis of the pathogenesis of a Guangzhou (GZ.1) pedigree with primary open-angle glaucoma (POAG). METHODS: DNA fragments of the trabecular meshwork inducible glucocorticoid response protein (TIGR) gene from 4 typical POAG patients and 2 normal subjects were amplified by polymerase chain reaction (PCR). The amplified PCR fragment was cloned into a pT-Adv vector, and direct sequencing was carried out on an ABI-373 automated DNA sequencer using dyeterminator chemistry to detect the mutation. RESULTS: The TIGR gene mutation was identified in the selected subjects of this pedigree. This mutation is a "C-to-T" transition at position 370, different from that of western countries and equivalent to the position change found in Japanese patients with familial POAG. No mutation was found in the TIGR gene fragment in 2 normal subjects of the pedigree. CONCLUSIONS: These preliminary results provide insights into the pathogenesis of POAG by the TIGR gene mutation, and into the underlying action of the different mutations in oriental and western peoples.

Cytoskeletal Proteins↗
PubMed1993

[Histochemical studies on the glycoconjugates of experimental alkali burned cornea in rabbit].

The model of experimental alkali burn of cornea in rabbit was obtained using 1 mol/L NaOH solution. After being burned for 1, 3, 7 and 14 days, the histochemical changes of these models were studied by using labelled concanavalin A (ConA-FITC) and wheat germ agglutinin (WGA-FITC). The results showed that after being burned, the amount of glycoconjugates interacted with these lectins decreased, and increased gradually after 7 days, then reached the level higher than that in the normal cornea. These changes were related to the recovery of alkali burned cornea.

Animals↗
PubMed1991

Prevention of graft-versus-host disease following allogeneic bone marrow transplantation in rats using FK506.

FK506 and cyclosporine were used for the prevention of acute graft-versus-host disease. Acute GVHD was induced in Lewis rats by total-body irradiation and subsequent reconstitution with allogeneic (ACI) bone marrow and spleen cells (BMTx). GVHD was assessed by both clinical and histologic parameters during the experiment duration of 60 days, and longer for selected animals. All untreated BM recipients died within 26 days from severe acute GVHD. GVHD was prevented with CsA during the period of immunosuppressive therapy, but it appeared within a few days afterward. FK506-treated BM recipients were also protected, but they had a markedly prolonged GVHD-free period after therapy was discontinued. Most such animals eventually developed GVHD but with notable exceptions. Maintenance therapy with doses of FK506 as low as 0.1 mg/kg every other day (1/20 of daily induction dose) was infallible insurance against delayed GVHD. The relevance of these findings to GVHD caused by lymphoid-containing solid organs such as the intestine was discussed.

Animals↗
PubMed1991

FK 506 reverses acute graft-versus-host disease after allogeneic bone marrow transplantation in rats.

Severe graft-versus-host disease was induced by transplantation of ACI rat bone marrow and spleen cells into irradiated Lewis rat recipients. Treatment with FK 506 or cyclosporine A (CsA) was started after clinical and histologic evidence of acute GVHD was present. A 14-day course of FK 506 at 1.0 mg/kg/day could rescue 100% of the animals suffering from GVHD. In contrast only one half of the animals treated with CsA at a high dose of 25 mg/kg/day recovered. After cessation of immunosuppressive therapy, FK 506-treated animals displayed a marked prolonged disease-free interval as compared to CsA-treated bone marrow recipients. Recurrence of the disease in these animals could be prevented when FK 506 treatment was continued after the induction period with a low maintenance dose of 0.1 mg/kg/day every other day.

Acute Disease↗
PubMed1990

Adoptive transfer of murine autoimmune orchitis with sperm-specific T lymphoblasts.

A protocol was successfully developed for reproducibly transferring experimental autoimmune orchitis (EAO) to naive recipient mice with sperm-specific T lymphoblasts. Cell donors were Balb/c mice immunized about 12 days earlier with homologous epididymal sperm capacitated in vitro with complete Freund's adjuvant. Draining lymph node cells were collected and subjected to a second challenge with the same sperm antigen in vitro. Sperm-specific T lymphoblasts were isolated on Percoll density gradients and propagated in the presence of interleukin-2 for 3 days and then were transferred intraperitoneally to naive recipients. As few as 3 x 10(6) sperm-specific T lymphoblasts were able to transfer EAO, which began on day 7 as infiltration of lymphocytes and macrophages and on days 14 to 21 developed to degenerative changes of spermatids and exfoliation of germinal epithelium. These pathologic alterations resemble a delayed type of hypersensitivity. The results show that sensitized T lymphoblasts can mediate an antigen-specific, mononuclear cell-invasive lesion in autoimmune orchitis.

Animals↗
PubMed1990

Evolution of hepatitis B virus liver disease after hepatic replacement. Practical and theoretical considerations.

The morphologic evolution of hepatitis B virus (HBV) liver disease in 45 hepatic allograft recipients who were HBV surface-antigen positive (HBs-Ag+) at the time of liver replacement and who survived for more than 60 days was studied by routine histologic and immunocytochemical analysis of serial pathology specimens. The findings in these patients were compared to a control group of 30 individuals who were immune to the HBV (anti-HBs antibody positive), but required hepatic replacement for other reasons. Eight of the forty-five (18%) HBsAg-positive patients have no serologic evidence of HBV reinfection after transplantation. All 37 remaining patients are reinfected; 21 (47%) developed chronic active hepatitis and/or cirrhosis, 3 (7%) developed submassive necrosis, and 6 (14%) developed chronic lobular hepatitis. One patient lost her graft to chronic rejection, despite reinfection with the B virus. Four other patients (9%) developed a chronic carrier state. No long-term follow-up biopsies were available in the remaining two patients. The histologic features associated with dysfunction related to recurrent HBV infection evolved from an acute to chronic phase and were similar to hepatitis B seen in nonallografted livers. Furthermore HBV-related lesions could be separated from rejection using routine histology alone. The only exception to this conclusion was the occurrence of a peculiar HBV-related lesion in two recipients, described herein. Immunohistochemical analysis demonstrated the presence of viral antigens in almost all cases. Hepatic inflammation also was commonly present during HBV disease and consisted mostly of accessory cells and T lymphocytes. Analysis of the effect of major histocompatibility complex matching revealed no clear association between the number of class I or II matches or mismatches and the development, or pattern, of active hepatitis in the allograft. Peculiar pathologic alterations in several of the biopsies and failed allografts after HBV reinfection suggests that, under special circumstances, the B virus may be cytopathic.

Graft Rejection↗