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Biomedical subjects

J Weng

Publications and source records attributed to J Weng.

At least 19 recordsLinked to original sources
PubMed2003

Characterization of surface oxide films on titanium and adhesion of osteoblast.

The relationship between surface characteristics of titanium and initial interactions of titanium-osteoblasts was investigated. Titanium plates were heat-treated in different oxidation atmospheres. The third passage rabbit osteoblasts were cultured on the titanium plates for 24h. After the heat-treatment, the crystal structure of the surface oxide films on titanium was identified using X-ray diffractometer and X-ray photoelectron spectroscopy (XPS). The surface roughness of titanium was measured with a profilometer. The surface energy was obtained by measurement of contact angles and calculation with Owens-Wendt-Kaeble's equation. The amount of surface hydroxyl (OH)(s) groups was examined using XPS. The change of binding energy of the some elements on the substrate surface suggested that the interactions between the cells and the titanium involved chemical reactions. The greater surface roughness, higher surface energy and more surface hydroxyl groups resulted in greater numbers of adhered osteoblasts and higher cell activity. Compared to the acidic hydroxyl (OH)(a) groups in (OH)(s) groups and the dispersion component of the total surface energy, the basic hydroxyl (OH)(b) groups and the polar component play more important roles in the osteoblast-titanium interaction.

Alkaline Phosphatase↗
PubMed2002

Relationship between blood pressure and finger photoplethysmographic waveform during oxygen desaturation test: a model fitting approach.

UNLABELLED: A modified 3-element windkessel model was applied to study the relationship between brachial arterial blood pressure and the photoplethysmographic waveform from pulse oximeters. Data were recorded from 12 healthy volunteers who underwent the oxygen desaturation study. During about 30 minutes recording period, the SpO2 value was regulated down till about 70%. After preprocessing, singular value decomposition (SVD) algorithm was then used to get the best fit of the model parameters. RESULT: the fitting error (RMSE) was 1.07 +/- 0.48 mmHg. The time constant of the model shown significant difference between the highest and the lowest saturation group.

Adult↗
PubMed2001

Functional consequences of mutations in the MODY4 gene (IPF1) and coexistence with MODY3 mutations.

AIMS/HYPOTHESIS: The aim of this study was to examine the putative role of mutations in the insulin promoter 1 (IPF1) gene in early-onset diabetes. METHODS: We carried out mutation screening of the IPF1 gene in 115 Scandinavian families with at least two members with onset of diabetes younger than 40 years. The allele frequencies were also tested in 183 unrelated patients with late-onset Type II (non-insulin-dependent) diabetes mellitus and in 92 non-diabetic control subjects. RESULTS: Two novel IPF1 variants (G212R and P239Q) and one previously reported (D76N) IPF1 variant were identified in the 115 families (3.5%). The D76N variant was found in one MODY3 family (S315fsinsA of HNF1alpha) and also in two families with late-onset Type II diabetes. The P239Q variant was identified in two families with early-onset diabetes including one with MODY3 (R272C of HNF1alpha) and in three families with late-onset Type II diabetes. Despite the fact that the variants did not segregate completely with diabetes, the non-diabetic carriers of the IPF1 variants had increased blood glucose concentrations (p < 0.05) and reduced insulin:glucose ratios (p < 0.05) during an oral glucose tolerance test compared with non-diabetic family members without these variants. In addition, when the G212R and P239Q variants were expressed in cells without IPF1 i.e.. Nes2y cells, both variants showed about a 50% reduction in their ability to activate insulin gene transcription compared to wild-type IPF1, as measured by reporter gene assay. CONCLUSION/INTERPRETATION: Although mutations in the IPF-1 gene are rare in early- (3.5 %) and late-onset (2.7 % ) Type II diabetes, they are functionally important and occur also in families with other MODY mutations.

Aged↗
PubMed2001

Three-dimensional sound localization from a compact non-coplanar array of microphones using tree-based learning.

One of the various human sensory capabilities is to identify the direction of perceived sounds. The goal of this work is to study sound source localization in three dimensions using some of the most important cues the human uses. In an attempt to satisfy the requirements of portability and miniaturization in robotics, this approach employs a compact sensor structure that can be placed on a mobile platform. The objective is to estimate the relative sound source position in three-dimensional space without imposing excessive restrictions on its spatio-temporal characteristics and the environment structure. Two types of features are considered, interaural time and level differences. Their relative effectiveness for localization is studied, as well as a practical way of using these complementary parameters. A two-stage procedure was used. In the training stage, sound samples are produced from points with known coordinates and then are stored. In the recognition stage, unknown sounds are processed by the trained system to estimate the 3D location of the sound source. Results from the experiments showed under +/-3 degrees in average angular error and less than +/-20% in average radial distance error.

Computer Systems↗
PubMed2001

Effect of excess degradable intake protein on early embryonic development, ovarian steroids, and blood urea nitrogen on days 2, 3, 4, and 5 of the estrous cycle in mature ewes.

Two trials were conducted to determine whether feeding excess degradable intake protein (DIP) during a synchronized estrous cycle and the first 5 d after breeding alters early embryonic development, ovarian steroids, or BUN concentrations in ewes. Ewes were group-fed in Trial 1 (T1) and individually fed in Trial 2 (T2) either 100 (control; T1, n = 15; T2, n = 12) or 200% (high-protein; T1, n = 16; T2, n = 12) of the NRC protein recommendation for maintenance during a synchronized estrous cycle until surgery in the next cycle. Ampullae (AMP), isthmi (IST), and uterine horns (UT) of high-protein and control ewes were removed on d 2 (T1), 3 (T2), 4 (T1), or 5 (T2) after breeding. In T1, jugular blood samples were taken once daily starting on d 2 of the synchronized cycle, and in T2 on d 2, 9, 15, 16, and 17, and in both trials from estrus (d 0) to the day of surgery. Ampullae, IST, and UT flushings were examined microscopically for the presence of embryos, embryo condition, and embryo cell number. There was no trial x treatment interaction (P > or = 0.10), so data for both trials were pooled. Concentrations of BUN were higher (P < 0.05) in high-protein-fed ewes than in control ewes during the synchronized cycle and the first 5 d of the next cycle. Progesterone concentrations of the synchronized cycle did not differ (P > 0.10) between treatments. During the first 5 d of the next cycle, estradiol-17beta concentrations were lower (P = 0.06) in high-protein-fed than in control ewes. Progesterone increased (P < 0.05) to higher concentrations by d 5 in high-protein-fed ewes than in control ewes. More (P < 0.05) embryos were found in AMP of high-protein-fed ewes than in AMP of control ewes on d 4. Fewer (P = 0.05) embryos were found in UT of high-protein-fed ewes than in UT of control ewes on d 4. More embryos were found in UT of high-protein-fed ewes than in UT of control ewes on d 5. Fewer (P = 0.05) embryos were found in IST of high-protein ewes than in the IST of control ewes on d 5. Embryos of high-protein-fed ewes had more (P < 0.05) cells than embryos from control fed ewes on d 5. Feeding ewes excess DIP protein during an estrous cycle and the first 5 d after breeding initially impeded embryo transport; thereafter, embryo transport and development through the oviduct was accelerated.

Animals↗
PubMed2001

Delayed dark-adaptation and lipofuscin accumulation in abcr+/- mice: implications for involvement of ABCR in age-related macular degeneration.

PURPOSE: To examine the ocular phenotype in mice heterozygous for a null mutation in the abcr gene. METHODS: Retinas and retinal pigment epithelia (RPE) were prepared from wild-type, abcr+/-, and abcr-/- mice. Fresh tissues were homogenized and analyzed by normal phase high-performance liquid chromatography (HPLC) for the presence of retinoids and phospholipids. In another study, fixed tissues were sectioned and analyzed by light and electron microscopy. Finally, anesthetized mice were studied by electroretinography (ERG) at different times after exposure to strong light. RESULTS: A2E, the major fluorophore of lipofuscin, and its precursors, A2PE-H(2) and A2PE, were approximately fourfold more abundant in 8-month-old abcr+/- than in the wild-type retina and RPE. The levels of these substances in abcr+/- mice were approximately 40% those in abcr-/- mice. Lipofuscin pigment-granules were also visible in abcr+/- RPE cells by electron microscopy. Accumulation of A2PE-H(2) and A2E in abcr+/- retina and RPE, respectively, was strongly dependent on light exposure. Heterozygous mutants also exhibited delayed recovery of rod sensitivity by ERG. This delay was correlated with elevated levels of all-trans-retinaldehyde (all-trans-RAL) in retina after a photobleach and was not caused by a reduction in quantum-catch due to depletion of 11-cis-retinaldehyde (11-cis-RAL). CONCLUSIONS: Partial loss of the ABCR or rim protein is sufficient to cause a phenotype in mice similar to recessive Stargardt's disease (STGD) and age-related macular degeneration (AMD) in humans. These data are consistent with the suggestion that the STGD carrier-state may predispose to the development of AMD.

ATP-Binding Cassette Transporters↗
PubMed2001

An automated fluorescent single strand conformation polymorphism technique for high throughput mutation screening.

OBJECTIVE: To develop a high throughput mutational detection method by multiple fluorescence-labeled polymerase chain reaction (PCR) products. METHODS: A total of 27 known mutations including 22 substitutions, 3 insertions (1, 2 and 7 bp) and 2 deletions (1 and 2 bp) in the hepatocyte nuclear factor (HNF)-4 alpha, glucokinase and HNF-1 alpha genes were tested. During nested PCR, amplified fragments were labeled with three fluorescent dyes. PCR products were visualized with an ABI-377 fluorescence sequencer using 5% glycerol or 10% sucrose in non-denaturing gel conditions. RESULTS: Twenty-five of 27 variants (93%) could be detected by combining 5% glycerol and 10% sucrose gel matrix conditions. Twenty-two of 27 (82%) and 18 of 27 (67%) variants were identified using 5% glycerol and 10% sucrose conditions, respectively. CONCLUSION: This fluorescence-based PCR single strand conformation polymorphism technique represents a simple, non-hazardous, time-saving and sensitive method for high throughput mutation detection.

Basic Helix-Loop-Helix Leucine Zipper Transcriptio↗
PubMed2001

[The effect of epidermal growth factor on the pathologic changes of gastric mucosa in SD rats with chronic atrophic gastritis].

OBJECTIVE: To study the effect of epidermal growth factor (EGF) on the pathologic changes of gastric mucosa in rats with chronic atrophic gastritis(CAG). METHODS: The established rat models of CAG were divided into therapy group and control group. The rats in the therapy group received EGF 10 microg/kg subcutaneously (SC), whereas these in the control group the same volume of normal saline SC. 12 weeks later, all rats were killed by cervical dislocation and their gastric mucosa were examined with microscope. RESULTS: The grade of inflammatory cell infiltration in the therapy group was lower than that in the control group (P < 0.01). The thickness of gastric mucosal gland layer was (215.0 +/- 20.7) microm in the therapy group and (139.2 +/- 13.8) microm in the control group (P < 0.01). The ratio of the thickness of gastric mucosal glands and muscularis mucosa(L(1)/L(2)) was 2.70 +/- 0.34 in the therapy group and 1.27 +/- 0.27 in the control group (P < 0.01). The number of gastric glands in 1 mm length of mucosal layer was 26.20 +/- 1.27 in the therapy group and 19.90 +/- 1.78 in the control group (P < 0.01). In the therapy group, the gastric glands were rearranged in order, without signs of malignant proliferation. The width of the expression of proliferating cell nuclear antigen (PCNA ) of gastric mucosa was higher in the therapy group than in the control group [(77.70 +/- 4.16) microm vs (54.40 +/- 4.54) microm, P < 0.01]. CONCLUSIONS: EGF played a therapeutic role in reversing the gastric mucosal atrophy of the rats with CAG. It promoted the expression of PCNA, which induced a protective proliferation of the gastric mucosal lesions in the rats with CAG.

Animals↗
PubMed2001

[The characteristics of bcl-2 and PCNA expression in the lens epithelium of human being].

OBJECTIVE: To investigate the characteristics of bcl-2 (gene inhibiting apoptosis) and proliferating cell nuclear antigen (PCNA) expression and their relation to the proliferation of lens epithelium. METHODS: The expression of bcl-2 and PCNA were detected by immunohistochemical streptavidin-peroxidase (SP) method. RESULTS: The expression of bcl-2 and PCNA in the lens epithelium of fetus and children was higher than that of the elderly, especially in the region of the lens equator. CONCLUSION: The over-expression of bcl-2 and PCNA in the lens epithelium of fetus and children suggests that bcl-2 and PCNA might be related to the development of cataract.

Adolescent↗
PubMed2001

[Spectral analysis on self-assembly ultrathin film of polyaminobenzonitrile].

Poly(p-amino benzonitrile) (PABN) was synthesized by the method of plasma polymerization. With the self-assembly techniques, an ultrathin film of PABN and NaPSS (sodium polystyrene sulfonate) was successfully prepared. UV-Visible absorption spectra revealed that the film is very regular. This is a new method to prepare ultrathin film of PABN.

Macromolecular Substances↗
PubMed2000

Biosynthesis of a major lipofuscin fluorophore in mice and humans with ABCR-mediated retinal and macular degeneration.

Increased accumulation of lipofuscin in cells of the retinal pigment epithelium (RPE) is seen in several forms of macular degeneration, a common cause of blindness in humans. A major fluorophore of lipofuscin is the toxic bis-retinoid, N-retinylidene-N-retinylethanolamine (A2E). Previously, we generated mice with a knockout mutation in the abcr gene. This gene encodes rim protein (RmP), an ATP-binding cassette transporter in rod outer segments. Mice lacking RmP accumulate A2E in RPE cells at a greatly increased rate over controls. Here, we identify three precursors of A2E in ocular tissues from abcr-/- mice and humans with ABCR-mediated recessive macular degenerations. Our results corroborate the scheme proposed by C. A. Parish, M. Hashimoto, K. Nakanishi, J. Dillon & J. Sparrow [Proc. Natl. Acad. Sci. USA (1998) 95, 14609-14613], for the biosynthesis of A2E: (i) condensation of all-trans-retinaldehyde (all-trans-RAL) with phosphatidylethanolamine to form a Schiff base; (ii) condensation of the amine product with a second all-trans-RAL to form a bis-retinoid; (iii) oxidation to yield a pyridinium salt; and (iv) hydrolysis of the phosphate ester to yield A2E. The latter two reactions probably occur within RPE phagolysosomes. As predicted by this model, formation of A2E was completely inhibited when abcr-/- mice were raised in total darkness. Also, once formed, A2E was not eliminated by the RPE. These data suggest that humans with retinal or macular degeneration caused by loss of RmP function may slow progression of their disease by limiting exposure to light. The precursors of A2E identified in this study may represent pharmacological targets for the treatment of ABCR-mediated macular degeneration.

ATP-Binding Cassette Transporters↗
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↗