Influence of saliva contamination on zirconia ceramic bonding

OBJECTIVES

The purpose of this study was to investigate the influence of saliva contamination and cleaning methods on adhesive bonding to dental zirconia ceramic with a phosphate-monomer-containing luting resin.

METHODS

After saliva immersion, airborne-particle abraded ceramic specimens were cleaned with water rinsing, with isopropanol, with phosphoric acid gel, or with additional airborne-particle abrasion. Airborne-particle abraded specimens without contamination were used as the control group. Chemical analysis of the ceramic surfaces of all groups was done using X-ray photoelectron spectroscopy (XPS). The influence of contamination and cleaning methods on ceramic bond durability was examined by tensile bond strength (TBS) testing after 3 days or 150 days water storage with 37,500 thermal cycles.

RESULTS

After saliva contamination XPS revealed an organic coating which was not removed completely with water rinsing, with isopropanol, or with phosphoric acid. Using TBS testing a strong influence of contamination and cleaning methods on resin bond strength and its durability was found.

SIGNIFICANCE

Saliva contamination significantly affected resin bonds to zirconia ceramic and its durability. Airborne-particle abrasion was the most effective cleaning method.

Posterior fossa abscesses secondary to dermal sinus associated with dermoid cyst in children

We report on the rare disease of posterior fossa abscesses secondary to dermal sinus associated with dermoid cyst in 4 pediatric cases seen over a 15-year of period. All children had a small dimple or a pinhole on the skin of the occipital region. On admission they had the signs of increased intracranial pressure, while 3 of them still suffered from signs of meningitis resulting from a bacterial infection through the dermal sinus. CT scan and MR images revealed both the route of the dermal sinus and intracranial lesions. Total resection was successfully achieved before various treatments in all patients without nervous sequelae. In conclusion, a posterior fossa dermoid cyst should be considered in all children with an occipital dermal sinus. Cerebellar abscesses will arise once bacterial infection has occurred through the associated dermal sinus. Radiological studies such as CT scans and MR images can help confirm the diagnosis and locate the lesions. Early neurosurgical interventions including external ventricular drainage, external abscess drainage and primary removal should be planned as soon as possible in accord with the children's condition.

Cloning of pig parotid secretory protein gene upstream promoter and the establishment of a transgenic mouse model expressing bacterial phytase for agricultural phosphorus pollution control

This study examined the feasibility of using the promoter of the pig parotid secretory protein (PSP) gene for expression of the phytase transgene in mouse models. The pig parotid secretory protein gene is specifically expressed at high levels in the salivary glands. The 10-kb upstream promoter region of the gene necessary for tissue-specific expression has been identified. We have constructed phytase transgenes composed of the appA phytase gene from Escherichia coli driven by the upstream promoter region of the pig PSP gene with a 3' tail of either bovine growth hormone or the pig PSP gene polyadenylation signal. Transgenic mouse models with the construct showed that the upstream region of the pig PSP gene is sufficient for directing the expression of phytase transgenes in the saliva. Expression of salivary phytase reduced fecal phytate by 8.5 and 12.5% in 2 transgenic mouse lines, respectively. These results suggest that the expression of phytase in salivary glands of monogastric animals offers a promising biological approach to relieve the requirement for dietary phosphate supplements and to reduce phosphorus pollution from animal agriculture.

Synthesis and cytotoxic activity of 3-phenyl-2-thio-quinoxaline 1,4-dioxide derivatives in hypoxia and in normoxia

A series of novel 3-phenyl-2-ethylthio/ethylsulfinyl/ethylsulfonyl/phenylthio/ phenylsulfonyl-quinoxaline 1,4-dioxide derivatives were synthesized and screened for their cytotoxicity in vitro on human leukaemia cell line HL-60, human esophagus cancer cell line ECA-109, human prostate cancer cell line PC-3, human gastric carcinoma cell line SGC-7901, and human breast cancer cell line MCF-7 in hypoxia and in normoxia. Half of tested compounds showed higher cytotoxic activity both in hypoxia and in normoxia. The mechanism of one potent compound, 67, in hypoxia showed that the mitochondria pathway is involved in the antitumor activity of this class of compounds.

Changes of CSF and spinal pathomorphology after high-concentration ozone injection into the subarachnoid space: an experimental study in pigs

BACKGROUND AND PURPOSE

Our aim was to explore the changes of CSF and spinal pathomorphology after high-concentration ozone injection into a pig's subarachnoid space.

MATERIALS AND METHODS

Eight experimental pigs were randomly divided into 4 groups (n=2 in each group). In groups A, B, C, and D, animals were sacrificed for pathology 1 day, 1 week, 1 month, and 3 months after the injection, respectively. Ozone (10 mL, 90 microg/mL) was injected along the lumbar 4-5 interspace into the subarachnoid space with a 21-ga Chiba needle under fluoroscopy. CSF collection and CT and MR imaging were performed before injection and 30 minutes, 1 week, 1 month, and 3 months after injection, respectively. The spinal cords were observed macroscopically and microscopically.

RESULTS

No serious behavior abnormalities were observed in any animals. There were no abnormalities in CSF and spinal cords pathologically and radiologically after injection.

CONCLUSION

Our initial study suggests that high-concentration ozone injection into a pig's subarachnoid space will not cause serious sequelae such as chemical arachnoiditis and necrosis of the spinal cord, and this finding provides evidence of the safety of ozone inadvertently injected into subarachnoid space in the clinical treatment of disk herniation.

Direct identification of propargyl radical in combustion flames by vacuum ultraviolet photoionization mass spectrometry

We have developed an effusive laser photodissociation radical source, aiming for the production of vibrationally relaxed radicals. Employing this radical source, we have measured the vacuum ultraviolet (VUV) photoionization efficiency (PIE) spectrum of the propargyl radical (C(3)H(3)) formed by the 193 nm excimer laser photodissociation of propargyl chloride in the energy range of 8.5-9.9 eV using high-resolution (energy bandwidth = 1 meV) multibunch synchrotron radiation. The VUV-PIE spectrum of C(3)H(3) thus obtained is found to exhibit pronounced autoionization features, which are tentatively assigned as members of two vibrational progressions of C(3)H(3) in excited autoionizing Rydberg states. The ionization energy (IE = 8.674 +/- 0.001 eV) of C(3)H(3) determined by a small steplike feature resolved at the photoionization onset of the VUV-PIE spectrum is in excellent agreement with the IE value reported in a previous pulsed field ionization-photoelectron study. We have also calculated the Franck-Condon factors (FCFs) for the photoionization transitions C(3)H(3) (+)(X;nu(i),i = 1-12)<--C(3)H(3)(X). The comparison between the pattern of FCFs and the autoionization peaks resolved in the VUV-PIE spectrum of C(3)H(3) points to the conclusion that the resonance-enhanced autoionization mechanism is most likely responsible for the observation of pronounced autoionization features. We also present here the VUV-PIE spectra for the mass 39 ions observed in the VUV synchrotron-based photoionization mass spectrometric sampling of several premixed flames. The excellent agreement of the IE value and the pattern of autoionizing features of the VUV-PIE spectra observed in the photodissociation and flames studies has provided an unambiguous identification of the propargyl radical as an important intermediate in the premixed combustion flames. The discrepancy found between the PIE spectra obtained in flames and photodissociation at energies above the IE(C(3)H(3)) suggests that the PIE spectra obtained in flames might have contributions from the photoionization of vibrationally excited C(3)H(3) and/or the dissociative photoionization processes involving larger hydrocarbon species formed in flames.

Transport measurements across a tunable potential barrier in graphene

The peculiar nature of electron scattering in graphene is among many exciting theoretical predictions for the physical properties of this material. To investigate electron scattering properties in a graphene plane, we have created a gate-tunable potential barrier within a single-layer graphene sheet. We report measurements of electrical transport across this structure as the tunable barrier potential is swept through a range of heights. When the barrier is sufficiently strong to form a bipolar junction (n-p-n or p-n-p) within the graphene sheet, the resistance across the barrier sharply increases. We compare these results to predictions for both diffusive and ballistic transport, as the barrier rises on a length scale comparable to the mean free path. Finally, we show how a magnetic field modifies transport across the barrier.

Epitope mapping of series of monoclonal antibodies against the hepatocellular carcinoma-associated antigen HAb18G/CD147

The hepatocellular carcinoma-associated antigen HAb18G/CD147, a member of CD147 family, could promote tumour invasion and metastasis via inducing the secretion of matrix metalloproteinases (MMP). Anti-CD147 monoclonal antibodies (MoAb) have exhibited obvious inhibitory effect on MMP induction. However, none of the epitopes of these MoAb has been reported. We previously prepared five MoAb against HAb18G/CD147, named HAb18, 3B3, 1B3, 5A5 and 4D2. To map the epitopes of these MoAb, a series of truncated fragments of extracellular region of HAb18G/CD147 was expressed in Escherichia coli and the MoAb-binding affinity to these fragments was examined with an enzyme-linked immunosorbent assay and Western blot. The residues (39)LTCSLNDSATEV(50), (36)KILLTCS(42) and (22)AAGTVFTTVEDL(33) were determined to be the epitopes of HAb18, 3B3 and 1B3, respectively, which were further proved by a dot-blot analysis with synthesized peptides and bioinformatics epitope prediction. The binding regions of MoAb 5A5 and 4D2 were located at residues E(120)-R(203). Then we constructed and expressed full-length HAb18G/CD147 and truncated HAb18G/CD147 without residues A(22)-V(50) in COS-7 cells. Gelatin zymography and Boyden chamber assay showed that the COS-7 cells expressing truncated HAb18G/CD147 failed to induce MMP production and enhance the cells' invasive potential, compared with the cells expressing full-length HAb18G/CD147. Taken together with the obviously inhibitory effects of HAb18 on the function of full-length HAb18G/CD147, these findings suggest that residues (22)AAGTVFTTVEDLGSKILLTCSLNDSATEV(50) may play a critical role in the functions of HAb18G/CD147 on MMP secretion and tumour invasion. These key residues can be used as potential drug target in cancer therapy.

Reversal of streptozotocin-induced diabetes in rats by gene therapy with betacellulin and pancreatic duodenal homeobox-1

Ultrasound-targeted microbubble destruction (UTMD) was used to direct betacellulin (BTC) and pancreatic duodenal homeobox-1 (PDX1) to rat pancreas 48 h after islet destruction by streptozotocin (STZ). Sprague-Dawley rats were rendered diabetic by STZ injection. Controls included normal rats, STZ only without UTMD, and UTMD with DsRed reporter gene. Blood glucose increased dramatically in all rats 48 h after STZ, and continued to rise after UTMD with BTC alone. Blood glucose declined from day 3 to day 10 after UTMD with PDX1, but remained elevated (261+/-8 mg/dl). However, in rats treated with both BTC and PDX1, blood glucose remained below 200 mg/dl throughout day 10. This was accompanied by normalization of blood insulin and C-peptide. Histology demonstrated islet-like clusters of glucagon-staining cells in the rats treated with BTC and PDX1, but these clusters disappeared by 30 days after UTMD treatment. Although regeneration of insulin-producing islets was not seen, diabetes was reversed for up to 15 days after a single UTMD treatment by ectopic insulin production by pancreatic acinar cells. These cells co-expressed amylase and insulin and demonstrated several beta-cell markers by reverse transcription-PCR. Gene therapy by UTMD can reverse diabetes in vivo in adult rats by restoring pancreatic insulin production.

Panavia F 2.0 bonding to contaminated zirconia ceramic after different cleaning procedures

OBJECTIVES

The purpose of this laboratory study was to evaluate the influence of different cleaning methods after saliva contamination and after using a silicone disclosing medium on the resin bond strength to zirconia ceramic. The hypothesis was that the resin-ceramic bond strength and its durability are related to the ceramic surface condition.

METHODS

Plexiglas tubes filled with composite resin were bonded to air-abraded zirconia ceramic disks using a phosphate monomer containing composite resin. Four surface cleaning methods were used after contaminating the ceramic surface: air abrasion with 50 mum Al(2)O(3) at 2.5 bar pressure for 15s, cleaning with 37% phosphoric acid for 60s once or for 30s twice, or cleaning in 96% isopropanol for 15s. The specimens of the control group were not cleaned after using the silicone disclosing medium. For each combination 16 specimens were bonded in an alignment apparatus. Subgroups of eight bonded specimens were tested for tensile bond strength (TBS) after storage for either 3 or 150 days combined with 37,500 thermal cycles. The statistical analyses were performed with the Kruskal-Wallis test, followed by multiple pair-wise comparisons using the Wilcoxon rank sum test.

RESULTS

The mean TBS ranged from 6.6 to 49.9 MPa after 3 days and from 0 to 19.8 MPa after 150 days. Air abrasion of the ceramic surface provided statistically significantly higher bond strengths than the other cleaning methods after 3 and 150 days. Alcohol cleaning of the ceramic did not provide durable bond strengths over time.

SIGNIFICANCE

Ceramic cleaning methods after try-in procedures have a significant influence on the resin-ceramic bond strength. Air abrasion of contaminated zirconia ceramic is the most effective.

321 PREGNANCIES ESTABLISHED FOLLOWING TRANSFER OF IN VITRO-PRODUCED FRESH AND FROZEN - THAWED BUFFALO (BUBALUS BUBALIS) EMBRYOS

The objective of this study was to evaluate the feasibility of obtaining pregnancies in the buffalo (Bubalus bubalis) species, following transfer of fresh and frozen–thawed in vitro-produced embryos during the months of April and May in southern China. Embryos produced from oocytes recovered by ovum pickup (OPU), from Murrah and Nili-Ravi buffaloes, were transferred into synchronized local F1 swamp � Murrah/Nili-Ravi heifers to establish pregnancies. In vitro maturation (IVM) was performed in 50-�L droplets of TCM-199 supplemented with 10% FBS, 0.5 �g mL-1 of LH, 5 �g mL-1 of FSH, and 1 �g mL-1 of estradiol in a humidified gas atmosphere of 5% CO2 in air at 39�C for 22 to 24 h. A concentration of 2 million spermatozoa was prepared in TALP supplemented with 0.6% BSA fraction V, 60 �g mL-1 of heparin, 0.2 mM penicillamine, and 0.1 mM hypotaurine, and co-incubated in 50-�L droplets up to 24 h. Co-culture on granulosa cell monolayer in TCM-199 supplemented with 10% FBS (GIBCO, Grand Island, NY), 0.25 mM Na pyruvate, and 50 �g mL-1 of kanamicin was allowed up to 8 days. A total of 923 antral follicles were punctured and 647 cumulus–oocyte complexes (COCs) were recovered (70%) over 3 replicates on 40 buffalo donors in twice-weekly collections. A total of 462 COCs were selected based on the presence of at least one layer of granulosa cells and were used for IVM and IVF, with a resulting cleavage of 257 (55.6%), leading to 22 morula (4.7%) and 93 blastocysts (20.1%). Embryo development was evaluated from Days 6 to 8, and grades 1 and 2 blastocysts to expanding blastocysts were used for transfer as fresh or following freezing and thawing. Recipients were synchronized by the Ovsynch protocol, and to match the recipient estrous cycle to the stage of in vitro embryo development, a second gonadotropin-releasing hormone was administered to recipients at the time of OPU on donors. For both fresh and frozen–thawed embryos, each recipient received 2 embryos into the uterine horn ipsilateral to the ovary bearing the corpus luteum. Following the Ovsynch protocol, a total of 26 out of 47 recipients (57.4%) were found to be suitable as recipients by palpation per rectum, receiving 52 fresh embryos and resulting in 7 pregnancies (26.9%). Thirty embryos were cryopreserved by conventional freezing using 1.8 M ethylene glycol and a freezing protocol, from seeding to plunging into liquid nitrogen, of -0.3�C min. Subsequently, embryos were transferred following thawing into 15 out of 20 recipients originally subjected to the Ovsynch protocol. Only 2 recipients were diagnosed as pregnant (13.3%). No statistical difference in pregnancy rate was found following the transfer of fresh vs. frozen–thawed embryos (P &gt; 0.05). Further improvements are needed to optimize the establishment of pregnancies. A closer monitoring by ultrasound of recipients subjected to synchronization protocols will favor a better selection of more suitable animals.

Methylation status of the fragile histidine triad and E-cadherin genes in plasma of cervical cancer patients

Recent evidence suggests that tumor cells may release DNA into the serum and plasma of afflicted cancer patients. However, no report existed regarding the methylation status of the fragile histidine triad (FHIT) and E-cadherin genes in plasma samples of cervical cancer patients. Methylation-specific PCR (MSP) was employed to examine CpG island methylation of the FHIT and E-cadherin genes in 151 pretreatment plasma samples and 30 tumor tissue samples from cervical cancer patients. MSP products were cloned and sequenced. CpG island methylation of the FHIT and E-cadherin genes was detected in 30.46% and 39.74% of plasma samples, respectively, and in 53.33% and 60.0% of tissue samples, respectively. The total concordance rate of methylation between plasma samples and tissue samples in FHIT gene was 80.00% and that in E-cadherin gene was 76.66%. At least one of the two methylated genes was detected in 56.29% of plasma samples and 76.7% of tissue samples. The presence of both methylated genes was detected in 13.9% of plasma samples and 36.67% of tissue samples. We found that the higher the clinical stage and histologic grade, the higher the rate of methylation in both genes in plasma samples. CpG island methylation of the FHIT and E-cadherin genes is present in plasma of cervical cancer patients. Using the two genes as markers simultaneously may allow clinicians to diagnose and evaluate the effect of treatment earlier and using fewer invasive procedures.

Genetic engineering of Periplaneta fuliginosa densovirus as an improved biopesticide

The smoky-brown cockroach (Periplaneta fuliginosa) densovirus (PfDNV) has previously shown potential in urban pest control. To improve its efficacy as a biopesticide, the genome of PfDNV was engineered by inserting the insect-specific toxin gene BmKIT1 in the open reading frame encoding the major structural proteins. A green fluorescent protein (GFP) marker was tagged to the BmKIT1 at its C-terminus for in vivo imaging using Confocal laser scanning microscopy (CFSM). Using a virion rescue strategy, the genomes of recombinant and wild-type (wt) PfDNV were then cotransfected in P. fuliginosa nymphs. Reverse transcription PCR (RT-PCR) showed that the inserted BmkIT1 genes were expressed in the P. fuliginosa nymphs 48 h after cotransfection. CFSM and transmission electron microscopy also confirmed the generation of virus particles and expression of BmKIT1-GFP fusion protein in the cotransfected nymphs. The recombinant viruses remained infective to P. fuliginosa nymphs in feeding tests. Using the LT(50) bioassay method, the coninfection of the recombinant and wt PfDNV killed the P. fuliginosa nymphs approximate 32% faster than wt PfDNV only. This is the first report showing the improvement of engineered densovirus for the potential application of biopesticide.

Long-term efficiency and stability of wetlands for treating wastewater of a lead/zinc mine and the concurrent ecosystem development

A constructed wetland system in Guangdong Province, South of China has been used for treating Pb/Zn mine discharge since 1985. The performance in the purification of the mine discharge and the concurrent ecosystem development within the system during the period of 1985-2000 has been studied. The untreated wastewater contained rather high concentrations of cadmium (Cd) (0.05 mg L(-1)), lead (Pb) (11.5 mg L(-1)), and zinc (Zn) (14.5 mg L(-1)), which greatly exceed the upper limits for industrial wastewater discharge in China. The constructed wetland system effectively removed Cd by 94.00%, Pb by 99.04%, Zn by 97.30%, and total suspended solids (TSS) by 98.95% from the mine discharge over a long period (over 16 years) leading to significant improvement in water quality; it was also found that there were no significantly annual or monthly variations in pH values, As, Cd, Hg, Pb, and Zn concentrations in water collected from the outlet of the wetland. Moreover, diversity and abundance of living organisms, including protozoan, higher plants, terrestrial animals, and birds, increased gradually. The 16-year monitoring results showed a reciprocal relationship, at a certain extent, between restoration of the wetland ecosystem, in other words, the maturity of the wetland, and the long-term efficiency and stability on purifying heavy metal-contaminated wastewater.

MCP-1 enhances excitability of nociceptive neurons in chronically compressed dorsal root ganglia

Previous experimental results from our laboratory demonstrated that monocyte chemoattractant protein-1 (MCP-1) depolarizes or increases the excitability of nociceptive neurons in the intact dorsal root ganglion (DRG) after a chronic compression of the DRG (CCD), an injury that upregulates neuronal expression of both MCP-1 and mRNA for its receptor CCR2. We presently explore the ionic mechanisms underlying the excitatory effects of MCP-1. MCP-1 (100 nM) was applied, after CCD, to acutely dissociated small DRG neurons with nociceptive properties. Under current clamp, the proportion of neurons depolarized was similar to that previously observed for CCD-treated neurons in the intact ganglion, although the magnitude of depolarization was greater. MCP-1 induced a decrease in rheobase by 44 +/- 10% and some cells became spontaneously active at resting potential. Action potential width at a voltage equal to 10% of the peak height was increased from 4.94 +/- 0.23 to 5.90 +/- 0.47 ms. In voltage clamp, MCP-1 induced an inward current in 27 of 50 neurons held at -60 mV, which increased with concentration over the range of 3 to 300 nM (EC(50) = 45 nM). The MCP-1-induced current was not voltage dependent and had an estimated reversal potential of -27 mV. In addition, MCP-1 inhibited a voltage-dependent, noninactivating outward current, presumably a delayed rectifier type K(+) conductance. We conclude that MCP-1 enhances excitability in CCD neurons by, at least, two mechanisms: 1) activation of a nonvoltage-dependent depolarizing current with characteristics similar to a nonselective cation conductance and 2) inhibition of a voltage-dependent outward current.