Root canal therapy is the most efficient way to treat pulptitis and periapical inflammation, which can clear infections of root canal systems, fill the root canal firmly, and avoid reinfection. However, the variations in root canal morphology and complexity of infection confer difficulty in thoroughly eliminating microorganisms and their by-products in the root canal system, especially in the root apex area (including the top one-third of the root canal and periapical tissue), which is described as the hardest area to clean during endodontic treatment. Infection is difficult to remove entirely because the apex area is hard to approach using dental instruments and because of the existence of special morphological structures, such as apical ramification, intercanal anastomoses, and lateral branch of root canal. This review gives a brief introduction of the characteristics and difficulties of apical infection and knowledge on how to control such infections, including root apex preparation, irrigation and disinfection, and root canal filling.
Dental Pulp Cavity ; Humans ; Infection Control ; Periapical Periodontitis ; Root Canal Filling Materials ; Root Canal Irrigants ; Root Canal Obturation ; Root Canal Preparation ; Root Canal Therapy

In order to solve the problem of selection and in vivo delivery problem in siRNA treatment, hepatitis B virus (HBV) HBx gene which could be targeted by siRNA was studied. The siRNA expression plasmid which specific inhibits HBx expression was obtained by in vitro selection via a dual-luciferase plasmid including HBx-Fluc fusion protein expression domain. The selected siRNA expression plasmid was then encapsulated in PEG-modified cationic liposome, which was devoted into pharmacodynamic studies at both cellular and animal level. The results illustrated that the cationic liposome which encapsulated siRNA expression plasmid could effectively inhibit HBx gene expression both in vitro and in vivo.
Cations ; Gene Expression Regulation, Viral ; drug effects ; Hepatitis B virus ; genetics ; Liposomes ; chemistry ; Plasmids ; RNA, Small Interfering ; chemistry ; Trans-Activators ; genetics ; metabolism

OBJECTIVE To study the isolation and resistance tendency of Acinetobacter calcoaceticus-baumannii to antimicrobial agents from 1998 to 2004 to provide valuable data for infection prevention and therapy. METHODS We reviewed the isolation rates,distribution in clinical specimens and wards,and the resistance rates of(A.calcoaceticus-baumannii)to 14 kinds of antimicrobial agents from 1998 to 2004. RESULTS There was an increasing tendency of isolation rates of A.calcoaceticus-baumannii every year,which was 0.18% in 1998 but 1.48% in 2004.In the seven years,there was the highest isolation rate of 70.58% in specimens from respiratory tract,the next was from the urine(9.42%),and blood(4.63%).Concerning the wards distribution,ICU had the highest rate of 47.28%.In 1998,A.calcoaceticus-baumannii had resistance rates more than 50% only to one kind of antimicrobial agents(aztreonam),but in 2004,it had increased to thirteen kinds(except cefoperazone/sulbactam).About the fourteen kinds of antimicrobial agents we inspected,that were increased in their resistance rate.The highest increasing of resistance rate was ceftazidime from 11.1% in 1998 to 88.9% in 2004,the imipenem was second for 0.0% to 64.8%,and the third was sulfamethoxazole/trimethoprim form 0.0% to 64.0%,while there still was an increasing resistance tendency to them. CONCLUSIONS The clinical isolation rate of A.calcoaceticus-baumannii is increasing,and it has higher resistance rates to many antimicrobial agents as well as an increasing resistance tendency to relatively susceptive antimicrobial agents every year.So physicians should prescribe on the basis of antimicrobial agents susceptibility tests in vitro.

Objective To study the inhibitory effect of pterin acid (PTA) against ricin and recombinant ricin A chain protein. Methods Luciferase protein synthesis inhibition assay in a cell-free system and in vitro cytotoxicity experiments were performed to assess the biological activity of ricin and rRTA treated with PTA.Results The result showed that PTA could significantly inhibit the activity of ricin and rRTA in a dose-dependent manner.Conclusion PTA might be used as a small molecular probe to develop an evaluating system for ricin/RTA small molecular inhibitor in vitro. The cell-free system adopted in the current study could also serve as a necessary basis for screening some novel small molecular compounds against ricin and RTA in the future.

Bletilla striata has been used as traditional Chinese medicine for several centuries. In recent years, the quality and quantity of wild B. striata plants have declined sharply due to habitat deterioration and human over-exploitation. Therefore, it is of great urgency to evaluate and protect B. striata wild plant resource. In this study, sequence-related amplified polymorphism (SRAP) markers were applied to assess the level and pattern of genetic diversity in twelve populations of B. striata. The results showed a high level of genetic diversity (PPB = 90.48%, H = 0.349 4, I = 0.509 6) and moderate genetic differentiation among populations (G(st) = 0.260 9). Based on the unweighted pair-group method with arithmetic average (UPGMA), twelve populations gathered in three clusters. The cluster 1 included four populations. There are Nanjing, Zhenjiang, Xuancheng and Hangzhou. The seven populations which come from Hubei Province, Hunan Province, Jiangxi Province and Guizhou Province belonged to the cluster 2. The cluster 3 only contained Wenshan population. Moreover, Mantel test revealed significant positive correlation between genetic distances and geographic distances (r = 0.632 9; P < 0.000 1). According to the results, we proposed a series of conservation consideration for B. striata.
China ; Genetic Markers ; Genetic Variation ; Genetics, Population ; Orchidaceae ; genetics ; Phylogeny ; Plants, Medicinal ; genetics

OBJECTIVETo investigate the effect of experimentally created occlusal disorders (ECOD) on the expression of estrogen in rat condylar cartilage.

METHODSThe model of ECOD was created by moving right upper and left lower first molars anteriorly. The animals in ECOD were sacrificed at 2, 4, 6, 8 weeks later. In removed occlusal disorders group, the moved first molars were extracted at 6 weeks later, and the animals were sacrificed 2 weeks later. The expression of estrogen was detected by SABC technique of immunocytochemistry, and then was analyzed by the density of estrogen-positive chondrocytes.

RESULTS1) Estrogen was abundant in mature layer and hypertrophic layer of rat mandibular condylar cartilage. 2) In control group, the expression of estrogen decreased gradually from 6-week-old to 16-week-old. 3) In both childhood and puberty rats, the expression of estrogen in experiment group was significantly higher at 2 weeks after treatment, while no difference was found at 4, 6, 8 weeks after treatment. However, the expression in removed occlusal disorder group was higher than that in control group and 8 weeks of ECOD group.

CONCLUSIONIn rat condylar cartilage, the expression of estrogen de-creases with age. Induced by ECOD, the expression of estrogen increases in early stage of remodelling activity.

Animals ; Cartilage, Articular ; Chondrocytes ; Estrogens ; Immunohistochemistry ; Mandibular Condyle ; Molar ; Rats ; Sexual Maturation

OBJECTIVESome research has shown that hyperbaric oxygen (HBO) can decrease the rate of mortality and disability caused by hypoxic-ischemic encephalopathy (HIE) in neonates. However, the HBO pressure used in the clinical reports and the efficacy of HBO are different. This study was designed to investigate the efficacy of HBO therapy under different pressures by observing the changes of peroxidation, antioxidant levels and brain vasomotor regulation factors as well as the score of neonatal behavioral neurological assessment (NBNA) in neonates with HIE after HBO therapy.

METHODSSixty neonates with HIE were randomly administered with 1.4, 1.5 or 1.6 atmosphere absolute (ATA) of HBO, once daily for seven days. Serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO) and nitric oxide synthase (NOS) were measured before and after HBO therapy. Meanwhile, NBNA and eye ground examination were performed.

RESULTSSerum SOD level increased and serum levels of MDA, NO and NOS decreased significantly after HBO therapy in the three HBO therapy groups (P<0.01). Serum SOD level was significantly higher and serum levels of MDA, NO and NOS were significantly lower in the 1.6 ATA HBO group than those in the 1.4 ATA group after therapy (P<0.05). The 1.6 ATA HBO group also showed increased SOD and decreased MDA levels compared with the 1.5 ATA HBO group after therapy (P<0.05). NBNA scores in the three groups increased significantly after HBO therapy (P<0.05). None of the three HBO therapy group patients showed abnormal eye grounds after therapy.

CONCLUSIONSHBO therapy with 1.4, 1.5 or 1.6 ATA is safe and effective for neonatal HIE. The antioxidant capacity increases with the increasing HBO pressure in neonates with HIE.

Female ; Humans ; Hyperbaric Oxygenation ; Hypoxia-Ischemia, Brain ; drug therapy ; physiopathology ; Infant, Newborn ; Male ; Malondialdehyde ; blood ; Nitric Oxide ; blood ; Nitric Oxide Synthase ; blood ; Pressure ; Superoxide Dismutase ; blood

BACKGROUNDDiabetic macrovascular complications are important causes of cardiovascular and cerebrovascular diseases and also one of the major causes of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). Phlorizin has been reported to be effective in reducing the blood glucose level in diabetic mellitus, while little is known about its effects on vascular complications. This study aimed to observe the effects of phlorizin on the aorta of diabetes db/db mice and explore its mechanism.

METHODSDiabetic db/db mice (n = 16) and age-matched db/m mice (n = 8) were divided into three groups: normal control group (CC group, db/m mice, n = 8), untreated diabetic group (DM group, db/db mice, n = 8) and diabetic group treated by phlorizin (DMT group, db/db mice, n = 8). Phlorizin (20 mg/kg body weight) was given in normal saline solution intragastrically for 10 weeks. Animals were weighed weekly. At the 10th weekend, all mice were fasted overnight and then sacrificed. Fasting blood was collected, and the aortas were dissected. The blood samples were analyzed for fasting blood glucose (FBG), serum advanced glycation end products (AGEs), malondialdehyde (MDA) and superoxide dismutase (SOD) activity, the aortic ultrastructure was studied.

RESULTSThe weight and serum concentration of FBG, AGEs, and MDA in the DM group were higher than that in the CC group (P < 0.01), and they were significantly lower in the DMT group (P < 0.05). Serum SOD activity was lower than that in the CC group (P < 0.01), and it is significantly higher in the DMT group (P < 0.05). The severity of aorta damage in the DMT group was less than that in the DM group.

CONCLUSIONSPhlorizin protected the db/db mice from diabetic macrovascular complications, attributed to the decreasing of blood glucose and AGEs level, and its antioxidant potential. This study may provide a new natural medicine for treating diabetic macrovascular complications.

Animals ; Aorta, Thoracic ; pathology ; Blood Glucose ; analysis ; Diabetic Angiopathies ; drug therapy ; pathology ; Glycation End Products, Advanced ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Phlorhizin ; therapeutic use ; Superoxide Dismutase ; metabolism

This study aimed to explore the mechanism of a novel mutation (p.Lys38Glu) in apolipoprotein H (APOH) gene causing hereditary beta2-glycoprotein Ⅰ (β2GPI) deficiency and thrombosis in a proband with thrombophilia.The plasma level of β2GPI was measured by ELISA and Western blotting,and anti-β2GPI antibody by ELISA.Lupus anticoagulant (LA) was assayed using the dilute Russell viper venom time.Deficiency of the major natural anticoagulants including protein C (PC),protein S (PS),antithrombin (AT) and thrombomodulin (TM) was excluded from the proband.A mutation analysis was performed by amplification and sequencing of the APOH gene.Wild type and mutant (c.112A＞G) APOH expression plasmids were constructed and transfected into HEK293T cells.The results showed that the thrombin generation capacity of the proband was higher than that of the other family members.Missense mutation p.Lys38Glu in APOH gene and LA coexisted in the proband.The mutation led to β2GPI deficiency and thrombosis by impairing the protein production and inhibiting the platelet aggregation.It was concluded that the recurrent thrombosis of the proband is associated with the coexistence ofp.Lys38Glu mutation in APOH gene and LA in plasma.

Group A rotavirus are the most frequently detected viral agent associated with the acute diarrhea in calves. In order to investigate the situation of rotavirus strains circulating in diary farms, a total of 117 fecal specimens were collected from diarrhea calves under 4 weeks-age on Yinluo diary farm in Daqing region in China from 2008 to 2009. Ten specimens were detected to be positive by a Rotavirus Group A Diagnostic Kit, which confirmed that the rotavirus was important viral agent associated with diarrhea in this diary farm. Based on the new classification system, G10P[11] genotype was determined in rotavirus positive samples. Sequence and Phylogenetic analysis indicated DQ-75 strain was introduced into our country with imported bovine.
Animals ; Cattle ; China ; Genotype ; Phylogeny ; Rotavirus ; classification ; genetics ; Rotavirus Infections ; virology