PubMed Health⌕ Search

Biomedical subjects

J Weng

Publications and source records attributed to J Weng.

At least 37 records · Page 2Linked to original sources
PubMed2000

Characterization of peroxide ions in hydroxyapatite lattice.

The incorporation of peroxide ions was confirmed in the heat treatment of hydroxyapatite (HA) powder under air as well as under oxygen atmosphere, by using X-ray diffraction, Raman, and infrared spectroscopy. Peroxide ions associated with vacancies were sited in the channel of HA lattice along the c-axis through the substitution of a portion of OH radicals. The molecular ions constituted a symmetric vibrator with a stretching vibration active in Raman spectrometry. This vibration was recorded at 750 cm(-1) in the Raman spectra of O(2)(2-)-containing HA samples. The final product was a solid solution of hydroxyl- and peroxide-apatite. However, the existence of peroxide ions in the HA lattice caused the contraction of the unit-cell dimensions of HA materials. In addition, a new hydrogen bond was formed between peroxide ions and adjacent OH radicals by using molecular spectroscopy analysis. During annealing treatment in air, peroxide ions decomposed and the substituted OH radicals re-enter the HA lattice, resulting in the elimination of the structural aberrations caused by the incorporation of peroxide ions. Concentration of the peroxide ions included in HA samples was measured by chemical analysis.

Biocompatible Materials↗
PubMed2000

Impaired insulin-stimulated expression of the glycogen synthase gene in skeletal muscle of type 2 diabetic patients is acquired rather than inherited.

To examine whether defective muscle glycogen synthase (GYS1) expression is associated with impaired glycogen synthesis in type 2 diabetes and whether the defect is inherited or acquired, we measured GYS1 gene expression and enzyme activity in muscle biopsies taken before and after an insulin clamp in 12 monozygotic twin pairs discordant for type 2 diabetes and in 12 matched control subjects. The effect of insulin on GYS1 fractional activity, when expressed as the increment over the basal values, was significantly impaired in diabetic (15.7 +/- 3.3%; P < 0.01), but not in nondiabetic (23.7 +/- 1.8%; P = NS) twins compared with that in control subjects (28.1 +/- 2.3%). Insulin increased GYS1 messenger ribonucleic acid (mRNA) expression in control subjects (from 0.14 +/- 0.02 to 1.74 +/- 0.10 relative units; P < 0.01) and in nondiabetic (from 0.24 +/- 0.05 to 1.81 +/- 0.16 relative units; P < 0.01) and diabetic (from 0.20 +/- 0.07 to 1.08 + 0.14 relative units; P < 0.01) twins. The effect of insulin on GYS1 expression was, however, significantly reduced in the diabetic (P < 0.003), but not in the nondiabetic, twins compared with that in control subjects. The postclamp GYS1 mRNA levels correlated strongly with the hemoglobin A1c levels (r = -0.61; P < 0.001). Despite the decrease in postclamp GYS1 mRNA levels, the GYS1 protein levels were not decreased in the diabetic twins compared with those in the control subjects (2.10 +/- 0.46 vs. 2.10 +/- 0.34 relative units; P = NS). We conclude that 1) insulin stimulates GYS1 mRNA expression; and 2) impaired stimulation of GYS1 gene expression by insulin in patients with type 2 diabetes is acquired and most likely is secondary to chronic hyperglycemia.

Aged↗
PubMed2000

[Study on relationship between endometrium laminin expression and irregular uterine bleeding in Norplant users].

OBJECTIVE: To investigate the relationship between endometrium laminin (LN) expression and irregular uterine bleeding in Norplant users. METHODS: Eighteen endomerium samples obtained during day 10-14th from Norlant users for 1/2, 1 or > 2 years respectively with irregular bleeding were studied morphologically and immunohistochemically for LN expression. Six normal proliferative endometria and 18 connterpacts with regular bleeding were used as control. RESULTS: In Norplant users, endometrial glands decreased in numbers and asynchromized in appearance. The LN expression on basal lamina of glandular epithelium and vascular endothelium was lower in those with irregular bleeding as compared with regular bleeders (P < 0.05). CONCLUSION: The decline of LN expression may related to irregular bleeding in Norplant users.

Adult↗
PubMed2000

[Preventive effects of three kinds of inactive vaccines against epidemic hemorrhagic fever (EHF) after 5 years of vaccination].

OBJECTIVE: To observe the safety and the preventive effects of three kinds of vaccines as Mongolian gerbils kidney vaccine, mouse brains vaccine and hamster kidney vaccine inoculated 5 years ago. METHODS: Field study and laboratory tests were carried out by random grouping and IFAT, MCPENT, ELISA, HI tests. RESULTS: The antibody-dependent enhancement did not appear in all individuals who received vaccines after four or five years. The seroconversion rates of MCPENT were 8.97%, 11.76% and 18.75% while the seroconversion rates of IFAT were 20.73%, 30.22% and 23.40% respectively for Mongolian gerbils kidney vaccine, mouse brains vaccine and hamster kidney vaccine. The protection rates were 100% for all three kinds of inactive vaccines which showed good epidemiological efficacy. CONCLUSION: The vaccines can protect clinical infection of EHF effectively after four or five years of the initial vaccination.

Animals↗
PubMed2000

[The changes in serum antibody level after immunization with HFRS vaccine].

OBJECTIVES: To observe the changes in serum antibody level after mass immunization with vaccine against hemorrhagic fever with renal syndrome (HFRS) and to evaluate its efficacy and effectiveness in the prevalent areas. METHODS: Healthy people aged 16 to 60 years in the villages were recruited as study subjects, excluding those suffered from HFRS previously, going out for more than nine months and those with contraindications, and were randomly allocated into immunization and control groups with 10,460 and 16,159 persons, respectively. Specific IgG antibody was determined with indirect immunofluorescent assay (IFA) and neutralizing antibody (NA) was determined with micro CPE method. RESULTS: Two weeks after the full-course immunization, sero-conversion rate for IFA reached 100% in those sero-negative before immunization, with a 95% confidence interval of 96.3 - 100.0%, and that for NA 44.4%, with a 95% CI of 22.0% - 69.0%. Geometric mean titer (GMT) were 72.1 and 4.6 for IFA and NA, respectively. Booster immunization was provided for them one year later. Positivity of IFA and NA was 28.6%, 83.3%, 75.0%, 53.1%, 22.6% and 14.8%, 55.6%, 35.0%, 31.3%, 26.0%, before booster immunization, two weeks, one year, one and a half years, two years after booster immunization, respectively. CONCLUSION: HFRS vaccine had good immunogenicity, but its duration of serum antibody sustenance was relatively short.

Adolescent↗
PubMed2000

[Evidence for TCR Vbeta clonal expansion T cells in a patient with cGVHD after unrelated donor BMT].

OBJECTIVE: To investigate the distribution and clonal expansion of TCR Vbeta subfamily T cells in patients with cGVHD after unrelated donor bone marrow transplantation (BMT). METHODS: The CDR3 of 24 TCR Vbeta subfamily genes were amplified from peripheral mononuclear cells of a patient with cGVHD after unrelated BMT. RT-PCR was used for detection of the distribution of TCR Vbeta repertoire, and the PCR products were further analyzed by genescan technique for the CDR3 size, to evaluating clonality of the detectable TCR VbetaT cells. RESULTS: Only 8 Vbeta subfamily T cells could be identified in the patient, clonal expansion T cells could be found of Vbeta2, 3, 8 and 13 subfamilies. CONCLUSIONS: The skew distribution and clonal expansion of TCR Vbeta subfamily T cells could be found in the patient. It may relate to the initiation of cGVHD.

Acute Disease↗
PubMed1999

Analysis of the rds/peripherin.rom1 complex in transgenic photoreceptors that express a chimeric protein.

Mice homozygous for the retinal degeneration slow (rds) mutation completely lack photoreceptor outer segments. The rds gene encodes rds/peripherin (rds), a membrane glycoprotein in the rims of rod and cone outer segment discs. rds is present as a complex with the related protein, rom1. Here, we generated transgenic mice that express a chimeric protein (rom/D2) containing the intradiscal D2 loop of rds in the context of rom1. rom/D2 was N-glycosylated, formed covalent homodimers, and interacted non-covalently with itself, rds, and rom1. The rds.rom/D2 interaction was significantly more stable than the non-covalent interaction between rds and rom1 by detergent/urea titration. Analysis of mice expressing rom/D2 revealed that rds is 2.5-fold more abundant than rom1, interacts non-covalently with itself and rom1 via the D2 loop, and forms a high order complex that may extend the entire circumference of the disc. Expression of rom/D2 fully rescued the ultrastructural phenotype in rds+/- mutant mice, but it had no effect on the phenotype in rds-/- mutants. Together, these observations explain the striking differences in null phenotypes and frequencies of disease-causing mutations between the RDS and ROM1 genes.

Amino Acid Sequence↗
PubMed1999

Insights into the function of Rim protein in photoreceptors and etiology of Stargardt's disease from the phenotype in abcr knockout mice.

Rim protein (RmP) is an ABC transporter of unknown function in rod outer segment discs. The human gene for RmP (ABCR) is affected in several recessive retinal degenerations. Here, we characterize the ocular phenotype in abcr knockout mice. Mice lacking RmP show delayed dark adaptation, increased all-trans-retinaldehyde (all-trans-RAL) following light exposure, elevated phosphatidylethanolamine (PE) in outer segments, accumulation of the protonated Schiff base complex of all-trans-RAL and PE (N-retinylidene-PE), and striking deposition of a major lipofuscin fluorophore (A2-E) in retinal pigment epithelium (RPE). These data suggest that RmP functions as an outwardly directed flippase for N-retinylidene-PE. Delayed dark adaptation is likely due to accumulation in discs of the noncovalent complex between opsin and all-trans-RAL. Finally, ABCR-mediated retinal degeneration may result from "poisoning" of the RPE due to A2-E accumulation, with secondary photoreceptor degeneration due to loss of the RPE support role.

ATP-Binding Cassette Transporters↗
PubMed1999

The order of calcium and phosphate ion deposition on chemically treated titanium surfaces soaked in aqueous solution.

The mechanism of apatite deposition on chemically treated Ti surfaces still is being studied. In this study, simulated body fluid, calcium aqueous solution, phosphate aqueous solution, and accelerated calcification solution are used as media to investigate the order of calcium and phosphate ion deposition on chemically treated Ti surfaces. The results of inductively coupled plasma spectra, scanning electron microscopy, and energy dispersive X-ray analysis show that calcium deposition is the prerequisite for phosphate ion deposition.

Biocompatible Materials↗
PubMed1999

High frequency of mutations in MODY and mitochondrial genes in Scandinavian patients with familial early-onset diabetes.

AIMS/HYPOTHESIS: To investigate the contribution of mutations in maturity-onset diabetes of the young (MODY) and mitochondrial genes to early-onset diabetes with a strong family history of diabetes in a cohort with a high prevalence of Type I (insulin-dependent) diabetes mellitus. METHODS: Screening for sequence variants in the hepatocyte nuclear factor (HNF)-4alpha (MODY1), glucokinase (MODY2), HNF-1alpha (MODY3) genes and mitochondrial DNA was carried out in 115 Finnish and Swedish patients with early-onset ( </= 40 years) diabetes using the single strand conformation polymorphism (SSCP) technique and direct sequencing. Allele frequencies were compared with 118 patients with onset of diabetes Type II (non-insulin-dependent) diabetes mellitus after the age of 40 and 92 non-diabetic control subjects without a family history of diabetes. RESULTS: In total 52 sequence variants were found in the HNF-1alpha, HNF-4alpha and glucokinase genes, 12 of which were considered as MODY mutations. Three families had the A3243G mutation in the mitochondrial tRNA(Leu) gene, which resulted in an overall prevalence of these mutations of 13 %. CONCLUSION/INTERPRETATION: Among 115 Scandinavian families, mutations in the HNF-1alpha gene represented the most common cause of familial early-onset ( </= 40 years) diabetes: MODY3 (5.2 %) more than MODY2 (3.5 %) more than MIDD (2.6 %) more than MODY1 (1.7 %).

Adult↗
PubMed1999

Preliminary study on HA coating percutaneously implanted in bone.

A comparative investigation on the possibility of hydroxyapatite (HA) coating and pure Ti column to form biological sealing with skin tissue was completed in this study. HA coating and pure Ti column were percutaneously implanted in the tibia of rabbits. Compared with titanium (Ti) implant, HA coating forms epithelial sealing with skin tissue at 6 weeks postoperatively, while the Ti implant may loosen from the implanted site and be lost. The Ti column loosing rate at this time was 50%. However, once the Ti implant becomes fixed with the bone tissue, it can form epithelial sealing with skin tissue just like the HA coating, at 8 weeks postoperatively. At 8 weeks postoperatively, the epithelial sealing is not destroyed in spite of the fact that the HA coating is biodegraded. Our results show that the HA coating can become fixed with the bone faster than the Ti, which is beneficial for epithelial sealing formation. The main role of HA coating for epithelial sealing is beneficial for sealing at the initial period after it is implanted.

Animals↗
PubMed1999

[Effect of xuefu zhuyu decoction on function of platelet and endothelial cell].

OBJECTIVE: To explore the effect of Xuefu Zhuyu Decoction (XFZYD) on function of platelet and endothelial cell. METHODS: Through incubation of XFZYD, in different concentration, with platelet and human umbilical vein endothelial cell, the platelet membrane glycoprotein II b/III a complex and thrombomoduline (TM) of human umbilical vein endothelial cell were determined by radioimmunoassay. RESULTS: XFZYD in 40 mg/ml or 80 mg/ml could obviously inhibit the adenosine diphosphate induced glycoprotein II b/III a molecular expression, as compared with the control group, the difference was significant (P < 0.05, P < 0.01), but it did not influence the TM level significantly. CONCLUSION: XFZYD could inhibit the adenosine diphosphate induced activation of platelet through blocking the exposure of glycoprotein II b/III a complex.

Blood Platelets↗
PubMed1999

[The spectral study of the surface modified medical rubber].

In this article ,the drug-resistance of two kinds of medical rubber whose surfaces have been modified were investigated by ATR-FTIR and XPS. The experimental results show that the compositions of the two samples'surface and body are different. The surface is fluorinated rubber although the body is butyl rubber. The ratio of fluorine to carbon atom in sample Ii -1 is higher than that in sample I -1. The principal join between F and C is the form--CF2--in sample II -1,but in sample I -1 it is the form--CF2-- and--CHF--. The change for F/C of the different depth in sample II- 1 was relatively less than that in sample I -1 when they were etched by argon ion bundle in the same conditions.

Drug Packaging↗
PubMed1998

Immunogenicity of DNA vaccines expressing human immunodeficiency virus type 1 envelope glycoprotein with and without deletions in the V1/2 and V3 regions.

DNA vaccines that express the human immunodeficiency virus type 1 HXB-2 envelope glycoprotein (Env) with or without deletions of the major variable regions V1/V2 and V3 were tested for the ability to raise enzyme-linked immunosorbent assay (ELISA) and neutralizing antibody in New Zealand White (NZW) rabbits. Three forms of the Envs were examined: gp120, the surface (SU) receptor-binding domain; gp140, the entire extracellular domain of Env; and gp160, the complete form of Env. For the forms of Env containing the variable regions, the gp120-expressing DNA plasmid was more immunogenic than the gp140- or gp160-expressing DNA plasmids. Removing the V1/2 and V3 variable regions increased the immunogenicity of the gp140- and gp160-expressing DNAs. Deletion of the variable regions also resulted in antibody responses against determinants that were not presented by the forms of Env containing the variable regions. Despite the improved immunogenicity, removing the V1/V2 and V3 domains did not improve the ability of Env to raise neutralizing antibodies. These results suggest that increasing the exposure of internal structures of Env that include the CD4-binding site does not necessarily result in the generation of better neutralizing antibody.

AIDS Vaccines↗
PubMed1998

The human photoreceptor rim protein gene (ABCR): genomic structure and primer set information for mutation analysis.

Rim protein (RmP) is an integral membrane glycoprotein localized to the rims of photoreceptor outer-segment discs. It belongs to the ABC transporter superfamily, but its function in the retina has not been determined. The gene for human RmP (ABCR) is affected in several recessively inherited human retinal degenerations, including Stargardt's macular dystrophy, retinitis pigmentosa, and cone-rod dystrophy. The complete structure of ABCR has not been determined. Here, we report the cloning of the human ABCR gene and present its complete intron-exon structure. The gene contains 50 exons that range in size from 33 to 406 bp. Almost all of the splice junctions follow the AG/GT rule. We have identified the site of transcription initiation by 5' RACE. The first several hundred bases upstream of the transcription unit are relatively conserved between mouse and human and contain several predicted cis-regulatory elements including a TATA-like box at -27 bp, and two Ret-4-like elements that reportedly confer photoreceptor-specific gene expression. We also present a complete set of tested oligonucleotide primers for the amplification and analysis of exons 1-50 by the polymerase chain reaction. These data should help with the identification of new disease-causing mutations in ABCR.

ATP-Binding Cassette Transporters↗
PubMed1998

Biological evaluation of biphasic calcium phosphate ceramic vertebral laminae.

An artificial vertebral lamina with a dense inside surface and porous outside part, fabricated with a biphasic calcium phosphate (70% hydroxyapatite/30% tricalcium phosphate) (HA-TCP) ceramic (abbr. CVL), was evaluated by animal experiments. The animal experiments showed that at half a month postoperation, no bone formation occurred on the macropore surfaces of the implants, however, fibrous connective tissues and blood vessels had grown into the macropores, contributing to the early fixation of the CVLs. The degradation of TCP phase was detected through X-ray diffraction (XRD); in the meanwhile, needle-like and plate-like crystals were found in the materials through scanning electron microscopy (SEM), and infrared spectroscopy (IR) observations showed that the carbonate apatites similar to bone apatites began to occur in the materials. At one month postoperation, the degradation of the TCP phase became moderate, new bone began to grow into the porous structures of the implants, and further degradation of the implants provided rich Ca and P ions for new bone formation. The newly formed bone in the macropores of the implants increased with implantation time. At one year postoperation, the implant was completely fused with natural bone on the interfaces between them, new bone had grown into most of the porous structures of the implants, and a natural bone tissue layer formed on the inside surface of the artificial vertebral lamina. The new bone tissue layer played a more effective role in protecting the spinal cord and improving the spinal stability in the later implantation time.

Animals↗
PubMed1998

Studies of the neutralizing activity and avidity of anti-human immunodeficiency virus type 1 Env antibody elicited by DNA priming and protein boosting.

DNA vaccination is an effective means of eliciting strong antibody responses to a number of viral antigens. However, DNA immunization alone has not generated persistent, high-titer antibody and neutralizing antibody responses to human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env). We have previously reported that DNA-primed anti-Env antibody responses can be augmented by boosting with Env-expressing recombinant vaccinia viruses. We report here that recombinant Env protein provides a more effective boost of DNA-initiated antibody responses. In rabbits primed with Env-expressing plasmids, protein boosting increased titer, persistence, neutralizing activity, and avidity of anti-Env responses. While titers increased rapidly after boosting, avidity and neutralizing activity matured more slowly over a 6-month period following protein boosting. DNA priming and protein immunization with HIV-1 HXB-2 Env elicited neutralizing antibody for T cell line-adapted, but not primary isolate, viruses. The most effective neutralizing antibody responses were observed after priming with plasmids which expressed noninfectious virus-like particles. In contrast to immunizations with HIV-1 Env, DNA immunizations with the influenza virus hemagglutinin glycoprotein did not require a protein boost to achieve high-titer antibody with good avidity and persistence.

AIDS Vaccines↗