MTA is rarely applied in the repair of root fractured section. A case of maxillary second premolar which fractured ten years ago had been connected with MTA in this article and the cone beam CT was used to evaluate the treatment effect.
Bicuspid ; Cone-Beam Computed Tomography ; Glutamates ; Guanine ; analogs & derivatives ; Humans ; Pemetrexed ; Tooth Root

OBJECTIVETo evaluate the association between metabolism of arsenic and DNA oxidative damage in workers in a arsenic mill.

METHODSUrinary organic arsenic and 8-hydroxydeoxyguanine were detected in 37 workers highly exposed to arsenic and 16 administrative and logistic staff with mild exposure in a arsenic mill in Yunnan province, and also 28 local people who did not have the exposure in the near past time. The correlation between metabolism of arsenic and DNA oxidative damage was evaluated.

RESULTSThe urinary organic arsenic concentration was respectively (0.48 +/- 0.37) mg/L and (0.08 +/- 0.05) mg/L for men with high and low exposure, and was respectively 0.11 mg/L and (0.30 +/- 0.24) mg/ L for women with high and low exposure, while it was lower than 0.02 mg/L in the controls. Urinary 8-hydroxydeoxyguanine concentration was (18.07 +/- 11.68) micromol/mol creatinine, (11.79 +/- 8.25) micromol/mol creatinine, (10.07 +/- 3.04) micromol/mol creatinine for the males with high and low exposure and of controls, respectively, (P < 0.05), and it was 84.35 micromol/mol creatinine, (21.27 +/- 5.89) micromol/mol creatinine, (14.43 +/- 2.58) micromol/mol creatinine for females with high and low exposure and of controls, respectively. The female workers exposed to arsenic had higher urinary 8-hydroxydeoxyguanine levels than males did (P < 0.05). The increased tendencies of urinary 8-hydroxydeoxyguanine levels with the organic arsenic concentration were found in workers (r(s) = 0.279, P = 0.019).

CONCLUSIONOccupational individuals exposed to arsenic have obvious DNA oxidative damage, which is more severe in females. The difference of metabolism of arsenic may play a key role.

Adult ; Arsenicals ; urine ; China ; Female ; Guanine ; analogs & derivatives ; urine ; Humans ; Male ; Middle Aged ; Occupational Exposure ; analysis

AIMTo study the thermal stability, decomposition process and kinetics of such purine pharmaceuticals as aciclovir (Acv), penciclovir (Pcv), and their parent substance, guanine.

METHODSUsing infrared technique, accelerating test method and thermogravimetry to investigate the thermal decomposition processes and using Coast-Redfern method, MKN method and Ozawa method to deal with the data to get kinetic functions.

RESULTSThe decomposition process and the formed products were derived, the kinetic model function was suggested by comparison of the kinetic parameters.

CONCLUSIONPcv and Acv's degrading product for the first step is guanine. The sequences of their thermal stabilities is: Pcv > Acv. The two drugs' kinetic equation of thermal decomposition is expressed as: da/dt = Ae-Ea/RT2(1-alpha)3/2.

Acyclovir ; analogs & derivatives ; chemistry ; Drug Stability ; Guanine ; chemistry ; Hot Temperature ; Kinetics ; Thermodynamics ; Thermogravimetry

AIM: This study was designed to explore the effects of short-term and long-term pretreatment of diammonium glycyrrhizinate (GLN) on the pharmacokinetics of entecavir (ETV) in rats. METHODS: Male SD rats were randomized into short-term and long-term experimental groups, respectively. In the short-term experiment, the control group received saline, the low dose group received GLN 13.5 mg·kg(-1) and the high dose group received GLN 40.5 mg·kg(-1). ETV (0.09 mg·kg(-1)) was given i.g. 0.5 h after saline/GLN administration. For the long-term experiment, rats were allocated into two experimental designs. The control group received saline/ETV (0.09 mg·kg(-1)), the low dose group received GLN 13.5 mg·kg(-1)/ETV 0.09 mg·kg(-1) + GLN 13.5 mg·kg(-1), while the high dose group received GLN 40.5 mg·kg(-1)/ETV 0.09 mg·kg(-1) + GLN 40.5 mg·kg(-1); all administration was continued for 15 days. On the 16(th) day, 0.09 mg·kg(-1) ETV was administrated to all groups. Blood samples were obtained at different time points after ETV administration to determine plasma ETV concentrations. RESULTS: Pretreatment with glycyrrhizin resulted in no significant alterations in the main pharmacokinetic parameters of ETV in the short-term and long-term administration experiments. CONCLUSION Diammonium glycyrrhizinate has no effect on ETV pharmacokinetics in rats.
Animals ; Drug Interactions ; Glycyrrhizic Acid ; pharmacology ; Guanine ; analogs & derivatives ; blood ; pharmacokinetics ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo compare renal function in chronic hepatitis B (CHB) patients before and after antiviral treatment with either telbivudine or entecavir administered as monotherapy,as well as to assess the impact of these antivirals on renal function in patients with mild renal impairment and to provide evidence for optimizing each as an antiviral treatment of CHB.

METHODSA total of 120 patients with CHB were enrolled for study and treated with either telbivudine (600 mg/d) or entecavir (0.5 mg/d). The normalization rate of alanine aminotransferase (ALT), the undetectable rate of HBV DNA, the level of serum creatinine (CR) and the estimated glomerular filtration rate (eGFR) were compared from the baseline period to post-treatment week 52 weeks and to post-treatment week 104. The chi-square test and t-test were used for statistical analyses.

RESULTSAfter 104 weeks of telbivudine monotherapy, the patients showed significant improvement in renal function (vs. baseline), with improved creatinine level (t=2.917, P=0.005) and eGFR (t=-2.736, P =0.008). Treatment with entecavir monotherapy did not provide significant improvement in renal function (at week 104, creatinine and eGFR: t=-2.727, P =0.007 and t=2.218, P=0.028). However, subgroup analysis of the mean change in eGFR indicated that both telbivudinetreated patients and entecavir-treated patients who entered the study with the poorest eGFR (at baseline, less than 90 mL/min/1.73 m-2) had better eGFR improvement after treatment (25.93 ± 2.21, n=11 vs. 8.17 ± 10.14, n=7), and there was a significant difference between the telbivudine group than the entecavir group (t=4.323, P =0.001). Virological breakthrough was more frequent in the telbivudine group than in the entecavir group (at week 104, 15.0% vs. 1.7%, P=0.017).

CONCLUSIONCompared with entecavir monotherapy, telbivudine monotherapy provides a renoprotective effect in patients with CHB. While these results may suggest a benefit of telbivudine monotherapy for CHB patients with high risk for renal impairment, they do not support the application of telbivudine as a first-line therapy for nucleos(t)ide-na(i)ve HBV patients because of the related high rate of virological resistance.

Alanine Transaminase ; Antiviral Agents ; Creatinine ; Guanine ; analogs & derivatives ; Hepatitis B, Chronic ; Humans ; Kidney ; Kidney Function Tests ; Thymidine ; analogs & derivatives

No abstract available.
Antiviral Agents/*adverse effects ; Arabinofuranosyluracil/adverse effects/*analogs & derivatives ; Female ; Guanine/*analogs & derivatives/therapeutic use ; Hepatitis B, Chronic/*drug therapy ; Humans ; Male ; Muscular Diseases/*chemically induced

Adenine ; analogs & derivatives ; therapeutic use ; Guanine ; analogs & derivatives ; therapeutic use ; Hepatitis B, Chronic ; drug therapy ; Humans ; Lamivudine ; therapeutic use ; Nucleosides ; therapeutic use ; Organophosphonates ; therapeutic use

Adenine ; analogs & derivatives ; therapeutic use ; Guanine ; analogs & derivatives ; therapeutic use ; Hepatitis B, Chronic ; drug therapy ; Humans ; Lamivudine ; therapeutic use ; Nucleosides ; therapeutic use ; Organophosphonates ; therapeutic use

OBJECTIVETo investigate the efficacy of anti-hepatitis B virus (HBV) drugs for preventing vertical transmission of HBV and the safety of these drugs when given as treatment during pregnancy (to women) or insemination (to men).

METHODSCases of women and men who had taken anti-HBV drug therapy during pregnancy or insemination, respectively, were retrospectively selected for study from among 18 hospitals and 33 specialists in the Guangdong Province. Demographic, HBV infection and treatment data was collected for puerperal men or women and their newborns from the medical records.

RESULTSA total of 122 cases with detailed follow-up data were included in the study and including 74 women who were administered lamivudine (LAM) more than telbivudine (LdT) more than adefovir (ADV)more than entecavir (ETV) (hierarchy ranking by number of cases) and 48 men who were administered LAM more than ADV more than LdT more than ETV.None of the 122 newborns related to these cases showed HBV infection at 7 months of follow-up.None of the 74 puerperal women showed complications related to reproduction.There was one ease of a newborn being underweight at birth (2.1 kg), for which the mother had taken LdT during pregnancy. There was also one case of a newborn with a harelip and one case of a newborn with an inguinal hernia, for which both of the fathers had taken ADV during the time of insemination.

CONCLUSIONThis retrospective investigation carried out in Guangdong Province indicated that not only are anti-HBV drugs efficacious for blocking vertical transmission of HBV but also are safe for both mothers and infants when taken by fathers or mothers during the reproduction phases of insemination and pregnancy.

Adenine ; analogs & derivatives ; Antiviral Agents ; adverse effects ; therapeutic use ; Female ; Guanine ; analogs & derivatives ; Hepatitis B ; drug therapy ; Hepatitis B virus ; Humans ; Infant ; Infant, Newborn ; Infectious Disease Transmission, Vertical ; Lamivudine ; Male ; Mothers ; Organophosphonates ; Pregnancy ; Retrospective Studies ; Thymidine ; analogs & derivatives ; Time Factors

8-oxo-7,8-dihydroguanine (8-oxo-G) in DNA is a mutagenic adduct formed by reactive oxygen species. In Escherichia coli, 2,6-dihydroxy-5N-formamidopyrimidine (Fapy)-DNA glycosylase (Fpg) removes this mutagenic adduct from DNA. In this report, we demonstrate base excision repair (BER) synthesis of DNA containing 8-oxo-G with Fpg in vitro. Fpg cut the oligonucleotide at the site of 8-oxo-G, producing one nucleotide gap with 3' and 5' phosphate termini. Next, 3' phosphatase(s) in the supernatant obtained by precipitating a crude extract of E. coli with 40% ammonium sulfate, removed the 3' phosphate group at the gap, thus exposing the 3' hydroxyl group to prime DNA synthesis. DNA polymerase and DNA ligase then completed the repair. These results indicate the biological significance of the glycosylase and apurinic/ apyrimidinic (AP) lyase activities of Fpg, in concert with 3' phosphatase(s) to create an appropriately gapped substrate for efficient BER synthesis of DNA containing 8-oxo-G.
DNA Glycosylases/metabolism ; *DNA Repair ; DNA, Bacterial/*chemistry/*metabolism ; DNA-Formamidopyrimidine Glycosylase/metabolism ; Escherichia coli/*enzymology/*genetics ; Guanine/*analogs & derivatives/*metabolism