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Biomedical subjects

B Yu

Publications and source records attributed to B Yu.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Antitumor effects of cytosine deaminase and HSV-tk double suicide gene with adenovirus mediation on rectal cancer cells].

OBJECTIVE: To study antitumor effects of cytosine deaminase (CD) gene/5-fluorocytosine (5-FC) and herpes simplex virus thymidine kinase(HSV-tk) gene/ganciclovir (GCV) systems on rectal cancer cells with adenovirus mediation. METHODS: CD and HSV-tk double suicide genes were transinfected into HR-8348 rectal cancer cells with recombinant adenovirus mediation. The expression of CD and HSV-tk genes was detected with RT-PCR. Plating efficiency and MTT method were used to evaluate the antitumor effect of CD and 5-FC, HSV-tk and GCV systems. RESULTS: Adenovirus was recombined with pAdCMV-Link1(CD + tk), pAdCMV-Link1(-), pAdCMV-Link1(CD), and pAdCMV-Link1(tk) plasmids respectively. HR-8348 cells were infected with the recombined adenovirus and the high expression of CD and (or) HSV-tk genes was found in the corresponding group of tumor cells. Before use of prodrug 5-FC and GCV, the plating efficiency and survival rate of the cells in each group were without significantly different (P > 0.05). But the plating efficiency and survival rate of the tumor cells in pAdCMV-Link1(CD + tk) transinfection group were more highly inhibited than in control, pAdCMV-Link1(-) (P < 0.01) and single suicide gene transinfection groups (P < 0.05) after use of 5-FC and GCV. Combined of use CD and 5-FC, HSV-tk and GCV systems remarkably inhibited the plating efficiency and growth of tumor cells transinfected with double suicide genes. CONCLUSION: Transinfection of CD and HSV-tk double suicide genes has a powerful antitumor effect.

Adenoviridae↗
PubMed2001

Clinicopathologic study of mucosa-associated lymphoid tissue lymphoma of the salivary gland.

OBJECTIVE: To study the histopathologic features and pathogenesis of mucosa-associated lymphoid tissue lymphoma (MALT-oma) of salivary glands. METHODS: Clinical data, paraffin-embedded sections, immunohistochemical slides (SP method) and electron microscopic features of surgical specimens of 32 cases of salivary gland MALT-oma were studied. RESULTS: The patients were 27 males and 5 females, with a mean age of 54.76 years. The lesions were located in the parotid area in 17 cases, and in the submandibular gland in the remaining 15 cases. Much of the MALT-oma was replaced by infiltration of a great amount of centrocyte-like cells (CCL) as background and occasional large cells (centroblast- or immunoblast-like). In MALT-omas "lymphoepithelial lesions" were present. Immunohistochemically, CD20 expression was found to be positive and CD45RO expression was negative in all MALT-omas. CONCLUSION: Most of the MALT-omas are low grade malignant tumors and have a "homing back" phenomenon. The cases were managed by surgery and chemotherapy. In a few MALT-omas which turned into high grade malignant tumors, the prognosis was poor. Acquired MALT may develop as a reaction to autoimmune disease and infection. Hyper-immune reaction and MALT hyperplasia under stimulation may result in myoepithelial sialadenitis and lead to MALT-oma of the salivary gland.

Adolescent↗
PubMed2001

Endocytic routes of exogenous antigen in murine dendritic cells and macrophages.

OBJECTIVE: To compare the endocytic routes of exogenous antigen between murine dendritic cells (DCs) and macrophages (M phi s). METHODS: Murine bone marrow-derived DCs and peritoneal M phi s were pulsed with horseradish peroxidase (HRP)-5 nm colloidal gold for 10 minutes, then grouped and chased for 0-120 minutes in culture medium. Intracellular distribution of 5 nm colloidal gold was explored by means of the cellular enzymatic-chemistry of acid phosphatase and MHC II immuno-cytochemistry under electron microscope. RESULTS: After 10 minutes of pulse with HRP-5 nm colloidal gold and 30 minutes of chase, most HRP-5 nm gold particles internalized by DCs entered into MHC class II compartments (M II Cs), and a small portion entered into acid phosphatase-positive lysosomes. In contrast to DCs, most M phi s lysosomes were accessed by HRP-5 nm gold particles, and a small portion of HRP-5 nm gold particles entered into M II Cs. After 60 minutes of chase, 5 nm gold particles could hardly be seen within M phi s, whereas most 5 nm gold particles were still retained in DCs. CONCLUSIONS: The endocytic route of exogenous antigen in DCs seems to be different from that in M phi s. Antigens taken by M phi s mainly enter into lysosomes within 30 minutes. In the case of DCs, most internalized antigens enter into M II Cs, which may be related to their unique antigen-presenting function. In addition, M phi s seem to have more powerful capacity to scavenge exogenous antigen than DCs.

Acid Phosphatase↗
PubMed2001

[Effect of NaFeEDTA fortified soy sauce on iron deficiency anemia in students].

NaFeEDTA fortified soy sauce was given to 300 students with iron deficiency anemia (IDA) for 3 months. The subjects were divided into three groups: control group, low iron supplemented group (Fe 5 mg/d) and high iron supplemented group (Fe 20 mg/d). Hemoglobin (Hb), serum iron, serum ferrtin, erythrocyte protoporphyrin, total iron binding capacity and serum transferrin were evaluated before and after the study. The results showed that Hb, serum iron, ferrtin and transferrin of the intervention groups had improved and erythrocyte protoporphyrin, total iron binding capacity decreased. There were no differences between the two intervention groups after the trial. The parameters of both intervention groups were much better than those of the control group. The results suggested that NaFeEDTA fortified soy sauce had positive influence on IDA.

Adolescent↗
PubMed2001

[Investigation of a-SiOxNy thin film by infrared absorption].

Infrared absorptive characteristics of a-SiOxNy thin film was investigated by altering O and N content. Various molecular bonds were identified by the infrared absorption measurement. 1,105 and 865 cm-1 peaks are associated with single Si-O and Si-N modes respectively. When the O and N contents increase, the peaks associated with the symmetry and anti-symmetry modes of O-Si-O and N-Si-N are measured. For N-Si-O, the absorptive peaks of Si-O and Si-N mode are located at 1,036 and 890 cm-1 respectively.

Absorption↗
PubMed2001

[Study on calcium-cholate-phosphate ternary complexes by FTIR spectroscopy].

The aim of this paper was to examine the calcium-cholate-phosphate tenary complexes by FTIR spectroscopy. The results indicated that the mole ratio of cholate to phosphate were 1:3 and 1:4 in ternary complexes respectively when the initial mole ratio of cholate to phosphate were 3:1 and 1.5:1 in reaction. The FTIR spectroscopic results demonstrated that in the ternary complexes Ca2+ was coordinated with O in both COO- and PO(4)3- groups.

Calcium↗
PubMed2000

The removal of heavy metal from aqueous solutions by sawdust adsorption - removal of copper.

Locally available sawdust, a byproduct of the world industry, was found to be a low cost and promising adsorbent for the removal of copper(II) from wastewater. In this work, adsorption of copper on sawdust has been studied by using batch techniques. The equilibrium adsorption level was determined to be a function of the solution pH, contact time, and sorbate concentration. The equilibrium adsorption capacity of sawdust for copper was obtained by using linear Freundlich and Langmuir isotherms. Ion exchange is probably one of the major adsorption mechanisms for binding divalent metal ions to the maple sawdust. The results provide strong evidence to support the hypothesis of adsorption mechanism. It also supplies significant sawdust operation capacity data for engineering design.

Adsorption↗
PubMed2000

Differences in repositioning error among patients with low back pain compared with control subjects.

STUDY DESIGN: Trunk repositioning error was measured in 20 patients with chronic low back pain and 20 control subjects. OBJECTIVES: To measure trunk repositioning error as a method of measuring proprioception of the low back and to compare trunk repositioning error in patients with low back pain and in control subjects. SUMMARY OF BACKGROUND DATA: Although many current low back pain rehabilitation programs incorporate proprioceptive training, very little research has been performed on proprioception of the low back. METHODS: While standing with the legs and pelvis immobilized, the subject bent the trunk to a predetermined target position and then attempted to replicate the position. Repositioning error was calculated as the absolute difference between the actual target position and the subject-perceived target position. The multiple target positions in the frontal and sagittal planes were tested. Trunk position was measured with a 3Space Tracker, which analyzes the three-dimensional position of the body. RESULTS: Repositioning error in patients with low back pain was significantly higher than that of control subjects in flexion, and significantly lower than that of control subjects in extension. CONCLUSIONS: The increase in repositioning error of patients with low back pain during flexion implies that some aspects of proprioception are lost in patients with low back pain. The decrease in repositioning error in patients with low back pain in extension is not as easily explained, but could possibly be caused by increased activation of mechanoreceptors in facet joints.

Adult↗
PubMed2000

A novel and effective procedure for the preparation of glucuronides.

6-Phenylthio-6-deoxy-D-glucopyranosides were easily prepared from 6-hydroxy-D-glucopyranosides and employed as effective glycosyl donors or acceptors. And the resulting coupling products were then readily converted into the corresponding D-glucuronide-containing compounds.

Carbohydrate Conformation↗
PubMed2000

Genetic variants of IL-13 signalling and human asthma and atopy.

Asthma and atopy show epidemiological association and are biologically linked by T-helper type 2 (T(h)2) cytokine-driven inflammatory mechanisms. IL-4 operates through the IL-4 receptor (IL-4R, a heterodimer of IL-4Ralpha and either gammac or IL-13Ralpha1) and IL-13 operates through IL-13R (a heterodimer of IL-4Ralpha and IL-13Ralpha1) to promote IgE synthesis and IgE-based mucosal inflammation which typify atopy. Recent animal model data suggest that IL-13 is a central cytokine in promoting asthma, through the stimulation of bronchial epithelial mucus secretion and smooth muscle hyper-reactivity. We investigated the role of common genetic variants of IL-13 and IL-13Ralpha1 in human asthma, considering IgE levels. A novel variant of human IL-13, Gln110Arg, on chromosome 5q31, associated with asthma rather than IgE levels in case-control populations from Britain and Japan [peak odds ratio (OR) = 2.31, 95% CI 1.33-4.00]; the variant also predicted asthma and higher serum IL-13 levels in a general, Japanese paediatric population. Immunohistochemistry demonstrated that both subunits of IL-13R are prominently expressed in bronchial epithelium and smooth muscle from asthmatic subjects. Detailed molecular modelling analyses indicate that residue 110 of IL-13, the site of the charge-modifying variants Arg and Gln, is important in the internal constitution of the ligand and crucial in ligand-receptor interaction. A non-coding variant of IL-13Ralpha1, A1398G, on chromosome Xq13, associated primarily with high IgE levels (OR = 3. 38 in males, 1.10 in females) rather than asthma. Thus, certain variants of IL-13 signalling are likely to be important promoters of human asthma; detailed functional analysis of their actions is needed.

Adult↗
PubMed2000

Repositioning error in low back pain. Comparing trunk repositioning error in subjects with chronic low back pain and control subjects.

STUDY DESIGN: Repositioning error of the trunk was tested in 20 subjects with chronic low back pain and in 20 control subjects. The 3Space Tracker (Polhemus, Colchester, VT), a device that measures three-dimensional position in space, was used to determine the subject's trunk position. OBJECTIVES: To determine whether repositioning error is different in subjects with chronic low back pain than in control subjects. SUMMARY OF BACKGROUND DATA: Proprioception allows the body to maintain proper orientation during static and dynamic activities. In peripheral joint injuries, researchers have demonstrated a loss of some aspects of proprioception and improvement in outcome with retraining. Although the components of proprioception in subjects with low back pain have not been well studied, it is thought that these persons lose some elements of proprioception that can be measured in a quantifiable way. If so, then rehabilitation to improve these deficits is important. In this pilot study, one aspect of proprioception, repositioning error, was examined. METHODS: The subjects attempted to replicate target positions of the trunk in flexion, extension, lateral bending, and lateral rotation. Repositioning error was calculated as the absolute difference between the actual and the subject-replicated target positions. RESULTS: No significant difference was found in repositioning error between the control subjects and the persons with chronic low back pain. CONCLUSIONS: Because proprioception is complex and entails the use of many afferent receptors, it is difficult to measure any one afferent deficiency discretely. The authors believe that this study, in which one aspect of proprioception was measured in an indirect manner, provides important background information on low back position sense. Further studies analyzing aspects of proprioception in subjects with low back pain are recommended.

Adult↗
PubMed2000

Inhibition of subsets of G protein-coupled receptors by empty mutants of G protein alpha subunits in g(o), G(11), and G(16).

We previously reported that the xanthine nucleotide binding G(o)alpha mutant, G(o)alphaX, inhibited the activation of G(i)-coupled receptors. We constructed similar mutations in G(11)alpha and G(16)alpha and characterized their nucleotide binding and receptor interaction. First, we found that G(11)alphaX and G(16)alphaX expressed in COS-7 cells bound xanthine 5'-O-(thiotriphosphate) instead of guanosine 5'-O-(thiotriphosphate). Second, we found that G(11)alphaX and G(16)alphaX interacted with betagamma subunits in the presence of xanthine diphosphate. These experiments demonstrated that G(11)alphaX and G(16)alphaX were xanthine nucleotide-binding proteins, similar to G(o)alphaX. Third, in COS-7 cells, both G(11)alphaX and G(16)alphaX inhibited the activation of G(q)-coupled receptors, whereas only G(16)alphaX inhibited the activation of G(i)-coupled receptors. Therefore, when in the nucleotide-free state, empty G(11)alphaX and G(16)alphaX appeared to retain the same receptor binding specificity as their wild-type counterparts. Finally, we found that G(o)alphaX, G(11)alphaX, and G(16)alphaX all inhibited the endogenous thrombin receptors and lysophosphatidic acid receptors in NIH3T3 cells, whereas G(11)alphaX and G(16)alphaX, but not G(o)alphaX, inhibited the activation of transfected m1 muscarinic receptor in these cells. We conclude that these empty G protein mutants of G(o)alpha, G(11)alpha, and G(16)alpha can act as dominant negative inhibitors against specific subsets of G protein-coupled receptors.

3T3 Cells↗
PubMed2000

Synergistic effect of low-frequency ultrasound and sodium lauryl sulfate on transdermal transport.

Application of low-frequency ultrasound has been shown to enhance transdermal transport of drugs (low-frequency sonophoresis). In this paper, we show that the efficacy of low-frequency ultrasound in enhancing transdermal transport can be further increased by its combination with sodium lauryl sulfate (SLS), a well-known surfactant. The dependence of the ultrasound-SLS-mediated transport on ultrasound parameters, including intensity, net exposure time, and duty cycle, is discussed. The transdermal transport enhancement is proportional to ultrasound intensity as well as to exposure time, and is independent of duty cycle as long as the net exposure time is the same. The synergistic effect of SLS and ultrasound on transdermal transport increases linearly with SLS concentration. The enhancement is also proportional to the ultrasound energy density beyond a threshold value, which suggests that a certain minimum amount of energy density is required before noticeable changes in skin permeability occur. A similar dependence of the transdermal transport enhancement on energy density is observed in the case of the enhancement induced by ultrasound alone. Although the threshold energy density value in the presence of SLS is about 10 times lower than that in the case of ultrasound alone, the relationship between enhancement and energy density in the presence and in the absence of SLS is otherwise similar. Possible mechanisms for the synergistic effect of ultrasound and SLS are also discussed.

Aluminum↗
PubMed2000

Binding of conserved islet peptides by human and murine MHC class II molecules associated with susceptibility to type I diabetes.

The major histocompatibility complex (MHC) is the most important susceptibility locus for type I diabetes in humans and NOD mice. NOD mice express a single MHC class II molecule (I-Ag7) which carries a unique beta chain sequence. In humans, DQ alleles that encode DQ8 and DQ2 confer the highest risk for the disease. Soluble DQ8 and I-Ag7 were used to directly compare the binding specificity of these MHC molecules. Peptides from three islet antigens--insulin, GAD 65 and HSP 60--bound to both CQ8 and I-Ag7. These peptides included epitopes that are immunodominant in NOD mice, namely insulin (9-23), GAD (206-220) and HSP 60 (441-460). All of these peptide sequences are highly conserved between the human and murine antigens. The binding specificity of DQ8 and I-Ag7 was similar, but not identical, since two peptides eluted from splenocytes of NOD mice did not bind to DQ8. DQ8 formed long-lived complexes with the majority of these peptides, indicating that DQ8 is not a poor peptide binder. These results demonstrate functional similarities between human and murine MHC class II molecules that confer susceptibility to type I diabetes.

Amino Acid Sequence↗
PubMed2000

Downregulation of cyclin D1 alters cdk 4- and cdk 2-specific phosphorylation of retinoblastoma protein.

Progression of cells through the G1 phase of the cell cycle requires the assembly and activation of specific cyclin:cyclin-dependent kinase (cdk) complexes in a tightly regulated, sequential fashion. To more clearly define the temporal events leading to the G1/S transition, sequential changes in the expression of cyclin E and cdks 2, 4, and 6, as well as the phosphorylation of the retinoblastoma protein (pRb), were assayed in RA28 cells, a variant of human colon cancer RKO cells which were modified by transfection of an ecdysone-inducible antisense (AS) CD1 expression system. Induction of cyclin D1 antisense mRNA by the ecdysteroid, ponasterone A, resulted in a 55% decrease in cyclin D1 mRNA and a 58% decrease in CD1 protein levels. There was a 2.4-fold decrease in the ratio of hyperphosphorylated pRb (ppRb) to hypophosphorylated pRb, as well as a 60-75% decrease in cdk 2- and cdk 4-specific phosphorylated pRb proteins. Of interest, cyclin E-dependent phosphorylation (cdk2) decreased 2.5-fold at 3 h despite only a 30% decrease in cyclin E protein level. Levels of cdk 2, cdk 4, and cdk 6 decreased 40-70%, while levels of cyclin A and B were unaffected by induction of CD1 antisense. Induction of a CD1 antisense gene in a human colon cancer cell line resulted in rapid, concomitant changes in CD1 mRNA and protein, cyclin E, cdk2, cdk4, and cdk6, as well as the ratio of ppRb to pRb. In this system, growth regulatory events are tightly regulated and the perturbed expression of a single protein, CD1, rapidly alters expression of multiple regulatory proteins involved in the G1/S transition phase of cell cycle progression.

Blotting, Western↗