Leakage studies have been performed frequently, since a fluid-tight seal provided by various dental filling materials has been considered clinically important. The leakage of the various root-end filling materials has been widely investigated mostly dye penetration method. These dye studies cannot offer any information about the quality of the seal of a test material over a long period of time The purpose of this study was to evaluate the microleakage of root end cavities in blood contamination filled amalgam, intermediate restorative material(IRM), light cured glass ionomer cement(GI) and mineral trioxide aggregate(MTA) by means of a modified fluid transport model. Fifty standard human root sections, each 5mm high and with a central pulp lumen of 3mm in diameter, were and filled with our commonly used or potential root end filling materials after they were contaminated with blood. At 24h, 72h, 1, 2, 4, 8, and 12 weeks after filling, leakage along these filling materials was determined under a low pressure of 10KPa(0.1atm) using a fluid transport model. The results were as follows: 1. MTA group showed a tendency of decreasing percent of gross leakage (20ml/day) in process of time, whereas the other materials showed a tendency of increasing in the process time. 2. At the all time interval, GI group leaked significantly less than amalgam group and IRM group (p<0.05). 3. At the 4 weeks, the percentage of gross leakage in MTA group decreased to 0% thereafter, the low percentage of gross leakage was maintained in MTA group until the end of the experiment, whereas the percentage in IRM group increased to 100%. 4. At the 12 weeks, percentage of gross leakage was significantly low in MTA group(0%), comparison with GI group(40%), amalgam group(90%) and IRM group(100%), but there was no significant difference between latter two materials.
Acrylic Resins ; Glass ; Glutamates ; Guanine ; Humans ; Light ; Silicon Dioxide ; Pemetrexed

OBJECTIVES: The aim of this study was to compare apical sealing ability and physical properties of MTA, MTA - AH-plus mixture (AMTA) and experimental Portland cement - Epoxy resin mixture (EPPC) for a development of a novel retro-filling material. MATERIALS AND METHODS: Forty-nine extracted roots were instrumented and filled with gutta-percha. Apical root was resected at 3 mm and the retro-filling cavity was prepared for 3 mm depth. Roots were randomly divided into 3 groups of 15 roots each. The retro-filling was done using MTA, AMTA, and EPPC as the groups divided. Four roots were used as control groups. After setting in humid condition for 24 hours, the roots were immersed in 1% methylene blue dye solution for 72 hours to test the apical leakage. After immersion, the roots were vertically sectioned and photos were taken to evaluate microleakage. Setting times were measured with Vicat apparatus and digital radiographs were taken to evaluate aluminum equivalent thickness using aluminum step wedge. The results of microleakage and setting time were compared between groups using one-way ANOVA and Scheffe's post-hoc comparison at the significance level of 95%. RESULTS: AMTA and EPPC showed less microleakage than MTA group (p < 0.05). AMTA showed the highest radio-opacity than other groups and the novel EPPC showed 5 mm aluminum thickness radio-opacity. EPPC showed the shortest initial and final setting times than other groups while the MTA showed the longest (p < 0.05). CONCLUSIONS: Under the condition of this study, the novel composite using Portland cement-Epoxy resin mixture may useful for retro-filling with the properties of favorable leakage resistance, radio-opacity and short setting time.
Aluminum ; Glutamates ; Guanine ; Gutta-Percha ; Immersion ; Methylene Blue ; Pemetrexed

OBJECTIVETo study the effects of adramycin to disturb telomeric extention reaction mediated by telomerase of Tca8113 cells by inducing oligonucleotides that contain telomeric repeats to form guanine-quadruplex (G4) structures.

METHODSIn the presence of adriamycin, d(TTAGGG)4, d(TTAGAG)4, d(TTAGGG)5 and d(TTAGGGT) were analyzed by electrophoretic mobility shift assay. The mobility of d(TTAGGG)3, d(TTAGGG)4 and d(TrAGGG)5 in native polyacrylamide electrophoresis were observed. Methylation protection experiments were performed to investigate the effects of adriamycin on methylation of guanine in d(TTAGGG)4 and d(TTAGAG)4. The traditional telomeric repeats amplification protocol (TRAP) and modified TRAP-G4 assays were, respectively, used to analyze the different characteristcs of adriamycin's inhibiting telomeric extension mediated by telomerase of Tca8113 cells.

RESULTSAt 5.00 microg/mL of adriamycin, conversion of some of linear d(TrAGGG)4 and d(TrAGGG)5to the new, high-mobility bands formed by complex with special second structures were found in the mobility shift assay. Adriamycin at 1.25 microg/mL protected the G in d(TIAGGG)4 from methylating. Adriamycin at 2.50 microg/mL or 1.25 microg/mL partially inhibited the telomeric extension lengthened by telomerase of Tca8113 cells in TRAP assay, but completely did so in TRAP-G4 assay.

CONCLUSIONAdriamycin is able to disturb telomeric extention mediated by telomerase of Tca8113 cells by inducing oligonucleotides that contain telomeric repeats to form intra-molecular G4 structures.

DNA ; Doxorubicin ; G-Quadruplexes ; Guanine ; Nucleic Acid Conformation ; Telomerase ; Telomere

O ⁶-carboxymethyl guanine(O ⁶-CMG) is a highly mutagenic alkylation product of DNA that causes gastrointestinal cancer in organisms. Existing studies used mutant Mycobacterium smegmatis porin A (MspA) nanopore assisted by Phi29 DNA polymerase to localize it. Recently, machine learning technology has been widely used in the analysis of nanopore sequencing data. But the machine learning always need a large number of data labels that have brought extra work burden to researchers, which greatly affects its practicability. Accordingly, this paper proposes a nano-Unsupervised-Deep-Learning method (nano-UDL) based on an unsupervised clustering algorithm to identify methylation events in nanopore data automatically. Specially, nano-UDL first uses the deep AutoEncoder to extract features from the nanopore dataset and then applies the MeanShift clustering algorithm to classify data. Besides, nano-UDL can extract the optimal features for clustering by joint optimizing the clustering loss and reconstruction loss. Experimental results demonstrate that nano-UDL has relatively accurate recognition accuracy on the O ⁶-CMG dataset and can accurately identify all sequence segments containing O ⁶-CMG. In order to further verify the robustness of nano-UDL, hyperparameter sensitivity verification and ablation experiments were carried out in this paper. Using machine learning to analyze nanopore data can effectively reduce the additional cost of manual data analysis, which is significant for many biological studies, including genome sequencing.
Deep Learning ; Guanine ; Nanopore Sequencing ; Nanopores ; Porins/genetics*

Guanine aminohydrolase (GAH), one of purine metabolizing enzymes rich in the nervous system was proved to have identical amino acid sequence to a recently identified novel protein p51-nedasin, NE-dlg/SAP102-associated protein. Nedasin has been reported to localize at neuronal cell bodies and binds to SAP102, so it might have a role in modulating NMDA receptor 2B clustering of SAP102 or synaptic organization in neuronal cells. In this study, we localize GAH and SAP102 in rat retina using immunohistochemical method. Immunoreactivities are detected for both GAH and SAP102 in ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and pigment layer. They seemed to be colocalized in ganglion cells, amacrine cells, horizontal cells and pigment cells. The staining profile for SAP102 is almost identical with NMDA receptor 2B mainly in fibrous elements in both the inner and outer plexiform layer. Our results support the possibility of close structural relationship between GAH and SAP102 in specific retinal cells and GAH involvement in synaptic organization association with SAP102 in the rat retina.
Amacrine Cells ; Amino Acid Sequence ; Animals ; Ganglion Cysts ; Guanine Deaminase* ; Guanine* ; N-Methylaspartate ; Nervous System ; Neurons ; Rats* ; Retina* ; Retinaldehyde

OBJECTIVETo investigate the expression of RhoGDIalpha in human testes and spermatozoa, and compare the expression of RhoGDIalpha in the ejaculated spermatozoa from normozoospermic me and infertile patients men receiving in vitro fertilization (IVF).

METHODSThe localization of RhoGDIalpha in the human testis was determined by immunohistochemistry, and that in the pre-capacitated, capacitated and acrosome-reacted sperm by immunofluorescence. Western blot was used to detect the expression of RhoGDIalpha in the semen samples obtained from normozoospermic males (n = 10), IVF patients with high fertilization rates (> or = 60%, n = 12) and those with low fertilization rates (< 60%, n = 13).

RESULTSImmunohistochemistry showed that the RhoGDIalpha protein was located in all spermatogenic cells and highly expressed in the elongated spermatids. Immunofluorescence exhibited a high expression of RhoGDIalpha in the acrosome and flagellum of human sperm, which decreased in the acrosome after capacitation and disappeared after acrosome reaction. Western blot revealed an obviously decreased expression of RhoGDIalpha in the spermatozoa of the IVF patients with low fertilization rates (0.66 +/- 0.18), with statistically significant difference from those with high fertilization rates (0.97 +/- 0.17) and the normozoospermic men (1.13 +/- 0.21).

CONCLUSIONThe RhoGDIalpha protein is located in the acrosome and flagellum of human sperm, and might be involved in sperm movement, capacitation and acrosome reaction. The significantly reduced expression of RhoGDIalpha in the sperm of low-fertilization patients suggests that it may be a new diagnostic biomarker for male infertility, and has a potential application value in sperm selection for IVF.

Fertilization in Vitro ; Guanine Nucleotide Dissociation Inhibitors ; metabolism ; Humans ; Infertility, Male ; Male ; Sperm Motility ; Spermatozoa ; metabolism ; Testis ; metabolism ; rho Guanine Nucleotide Dissociation Inhibitor alpha ; rho-Specific Guanine Nucleotide Dissociation Inhibitors

BACKGROUND: The human Rho guanine nucleotide exchange factor 11 (ARHGEF11) functions as an activator of Rho GTPases and is thought to influence insulin signaling. The R1467H variant of ARHGEF11 has been reported to be associated with susceptibility to type 2 diabetes mellitus (T2DM) in Western populations. METHODS: We investigated the effects of the R1467H variant on susceptibility to T2DM as well as related traits in a Korean population. We genotyped the R1467H (rs945508) of ARHGEF11 in 689 unrelated T2DM patients and 249 non-diabetic individuals and compared the clinical and biochemical characteristics according to different alleles. RESULTS: The H allele was significantly more frequent in T2DM cases than in controls (P = 0.037, 17.1% and 13.1%; respectively). H homozygocity was associated with a higher risk of T2DM compared to those with R/R or R/H genotype (odds ratio, 5.24; 95% confidence interval, 1.06 to 25.83; P = 0.042). The fasting plasma glucose, HbA1c, fasting insulin, HOMA2-IR and HOMA2-%beta levels did not differ significantly between different genotypes. CONCLUSION: Our study replicated associations of the ARHGEF11 polymorphism with increased risk of T2DM in a Korean population and thus supports previous data implicating a potential role of ARHGEF11 in the etiology of T2DM. Further studies revealing the underlying mechanism for this association are needed.
Alleles ; Diabetes Mellitus, Type 2 ; Fasting ; Genotype ; Glucose ; Guanine ; Guanine Nucleotide Exchange Factors ; Humans ; Insulin ; Plasma ; Polymorphism, Single Nucleotide ; rho GTP-Binding Proteins

Guanine aminohydrolase (GAH; Guanine deaminase, EC 3.5.4.3) is an enzyme that has a role in purine catabolism. Most of the enzymes involved in purine catabolism have been studied for their biological functions, physiological roles and amino acid sequences, and biochemical activity of GAH is known to be detected in various organs such as liver, kidney, small intestine and brain. Its activity is also known to be changed during development of the nervous system. Although there have been studies on GAH, the histological distribution of GAH in the rat retina has not been examined until now. In this study, in order to investigate the cellular distribution and temporal regulation of GAH in rat retina, we performed immunohistochemistry in retinal sections at different developmental ages between postnatal day 0 (P0, birthdate) and the adult stage using specific antibody against GAH. GAH immunoreactivity was observed in the ganglion cell layer and inner plexiform layer at P0. From P5, GAH staining appeared in the inner part of the neuroblast layer, where amacrine cells localize. At P14, labeling of GAH also was observed in horizontal cell bodies and in the outer plexiform layer. Immunoreactivity of GAH in horizontal cell bodies was increased and strong punctate reactivity was observed in the outer plexiform layer at the adult rat retina, whereas the number and intensity of immunoreactive amacrine cell bodies in the inner part of inner nuclear layer decreased. From these results, we can suggest that GAH may be involved in the establishment of synaptic connections and signal transduction in the developing rat retina.
Adult ; Amacrine Cells ; Amino Acid Sequence ; Animals ; Brain ; Ganglion Cysts ; Guanine Deaminase* ; Guanine* ; Humans ; Immunohistochemistry ; Intestine, Small ; Kidney ; Liver ; Metabolism ; Nervous System ; Rats* ; Retina* ; Retinaldehyde ; Signal Transduction

PURPOSE: The HSV1-tk reporter gene system is the most widely used system because of its advantage that direct monitoring is possible without the introduction of a separate reporter gene in case of HSV1-tk suicide gene therapy. In this study, we investigate the usefulness of the reporter probe (substrate), 9-(4-[18F]fluoro-3-hydroxymethylbutyl)guanine ([18F]FHBG) for non-invasive reporter gene imaging using PET in HSV1-tk expressing hepatoma model. MATERIALS AND METHODS: Radiolabeled FHBG was prepared in 8 steps from a commercially available triester. The labeling reaction was carried out by NCA nucleophilic substitution with K[18F]/K2.2.2. in acetonitrile using N2-monomethoxytrityl-9-[4-(tosyl)-3-monomethoxytritylmethylbutyl]guanine as a precursor, followed by deprotection with 1 N HCl. Preliminary biological properties of the probe were evaluated with MCA cells and MCA-tk cells transduced with HSV1-tk reporter gene. In vitro uptake and release-out studies of [18F]FHBG were performed, and was analyzed correlation between [18F]FHBG uptake ratio according to increasing numeric count of MCA-tk cells and degree of gene expression. MicroPET scan image was obtained with MCA and MCA-tk tumor bearing Balb/c-nude mouse model. RESULTS: [18F]FHBG was purified by reverse phase semi-HPLC system and collected at around 16-18 min. Radiochemical yield was about 20-25% (corrected for decay), radiochemical purity was >95% and specific activity was around >55.5 GBq/micro mol. Specific accumulation of [18F]FHBG was observed in HSV1-tk gene transduced MCA-tk cells but not in MCA cells, and consecutive 1 hour release-out results showed more than 86% of uptaked [18F]FHBG was retained inside of cells. The uptake of [18F]FHBG was showed a highly significant linear correlation (R2=0.995) with increasing percentage of MCA-tk numeric cell count. In microPET scan images, remarkable difference of accumulation was observed for the two type of tumors. CONCLUSION: [18F]FHBG appears to be a useful as non-invasive PET imaging substrate in HSV1-tk expressing hepatoma model.
Animals ; Carcinoma, Hepatocellular* ; Cell Count ; Gene Expression ; Genes, Reporter ; Genetic Therapy ; Guanine* ; Mice ; Suicide ; Thymidine Kinase

Since its introduction in 1993, Mineral Trioxide Aggregate (MTA) has been shown to be superior to others in sealing, biocompatibility, and many other aspects of clinical endodontics. MTA is primarily Portland cement with bismuth oxide as a radiopacitifier. Although some studies suggested that the reasonable-priced Portland cement could be used instead of MTA, but MTAs are different from Portland cement in its composition, especially in heavy metal contents. Therefore, clinicians should be meticulous adapting the Portland cement as a MTA substitute.
Aluminum Compounds ; Bismuth ; Calcium Compounds ; Drug Combinations ; Endodontics ; Glutamates ; Guanine ; Oxides ; Silicates ; Pemetrexed