Epidermal Growth Factor Receptor Mutation Status and the Impact on Clinical Outcomes in Patients with Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) mutation status differs according to ethnicity, gender, smoking history, and histology types. The present study aimed to evaluate EGFR mutation status in patients with non-small cell lung cancer (NSCLC) and further explore its association with clinical characteristics and prognosis in advanced NSCLC patients (Stage IIIB-IV). 238 NSCLC patients were enrolled in this study from October 2016 through December 2019. Patient characteristics and clinical data including age, gender, smoking history, histology types, tumor stage, survival status, and time were collected via electronic medical record system or telephone. 21 somatic mutations which spanned exons 18-21 of EGFR were detected using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method, followed by analysis of links to clinical characteristics, progression-free survival (PFS) and overall survival (OS). 103 patients were detected harboring EGFR mutations among the 238 cases tested (43.3%), and exons 19 and 21 were the highest mutation frequencies, with 20.6% and 19.3% respectively. The EGFR mutation rate was much higher in female versus male (57.4% vs 31.5%, p <0.001), in non-smokers compared to smokers (56.8% vs 25.9%, p <0.001), and in those with adenocarcinoma than other histology types (48.3% vs 3.7%, p <0.001). For patients in advanced stage, median PFS was 11 months in patients harboring EGFR mutations, versus 4 months in patients with wild type EGFR (p <0.001); median OS was 24 versus 12 months (p <0.001). Never smoking (p = 0.042) and adenocarcinoma (p = 0.007) were independent favorable factors for EGFR mutations. Our data strengthen the findings of high prevalence of EGFR mutations in Asian patients with NSCLC. Mutations are prevalent in those patients who are female, adenocarcinoma, and have never smoked. Moreover, advanced EGFR mutation-positive patients have better PFS and OS than those with wild type EGFR.

[Analysis of specific sIgE detection of house dust mites and aspergillus fumigatus in 2 535 patients with respiratory allergic diseases and respiratory infectious diseases in the Guangzhou area]

Objective: To compare the specific IgE positive rates of the patients between allergic respiratory diseases and respiratory infectious diseases in Guangzhou, the relationship between the co-sensitization of house dust mite (HDM) allergen and Aspergillus fumigatus (AF) allergen and asthma, allergic rhinitis with asthma, pneumonia, upper respiratory infections, bronchitis, serum total immunoglobulin E (total Immunoglobulin E, tIgE) and age were analyzed, to provide the basis for the prevention and treatment of respiratory allergic diseases and respiratory infectious diseases in this area. Methods: A total of 2 535 patients with confirmed respiratory allergic diseases and respiratory infectious diseases were selected retrospectively from the outpatient or inpatient department of the First Affiliated Hospital of Guangzhou Medical University from April 2017 to June 2021 and detected HDM and AF specific IgE (sIgE) by the ImmunoCAP system. The age range was 1 to 89 years. The median age was 5 years. The average age was 9. ≤3 years old group n=894, 4-6 years old group n=721, 7-18 years old group n=615, 19-49 years old group n=207, >49 years old group n=98. There were 1 596 males (62.96%) and 939 females (37.04%). There were 1 279 cases of allergic diseases and 1 256 cases of respiratory infectious diseases. The different disease groups were divided into asthma group (411 cases), allergic rhinitis group (458 cases), allergic rhinitis combined with asthma group (410 cases), pneumonia group (463 cases), upper respiratory tract infection group (299 cases) and bronchitis group (494 cases). The difference of specific IgE (sIgE) and tIgE between HDM and AF was analyzed. For statistical analysis, continuous variables were tested by Mann-Whitney U. Classification data by chi-square test or Fisher's exact test. Results: 1 313 (51.79%) patients were sIgE positive for HDM allergen, 65 (2.56%) were sIgE positive for AF allergen, and 50 (1.97%) were both positive. In the respiratory allergic disease group, 877 cases (68.57%,877/1 279) were positive for HDM allergen sIgE, 57 cases (4.46%,57/1 279) were positive for AF allergen sIgE, and 44 cases (3.44%,44/1 279) were both positive; 436 cases (34.71%,436/1 256) of respiratory infectious diseases were positive for HDM allergen sIgE, 8 cases (0.64%,8/1 256) were positive for AF allergen sIgE, and 6 cases (0.48%,6/1 256) were both positive. In monosensitization, the HDM allergen sIgE sensitization rate was the highest in the allergic rhinitis & asthma group, at 80.24% (329/410). The positive rate of HDM allergen sIgE in male patients was 53.76%(858/1 596), and the positive rate in female patients was 46.22%(434/939), and the difference between the two was statistically significant (χ²=13.449, P<0.001). In polysensitization, asthma patients (5.35%,22/411) had the highest positive rate of HDM sensitization with AF, followed by allergic rhinitis patients (3.06%,14/458), allergic rhinitis with asthma (1.95%,8/410). The positive rate of respiratory infectious diseases such as pneumonia (0.43%,2/463), upper respiratory infections (0.33%,1/299), and bronchitis (0.61%,3/494) with AF was extremely low. The positive rate of HDM combined with AF in infants(≤3 years old group,0.34%, 3/894; 4-6 years old group, 0.97%, 7/721)was significantly lower than that in teenagers and adults(7-18 years old group,3.58%, 22/615; 19-49 years old group,6.28%, 13/207;>49 years old group,5.10%, 5/98).In the patients with HDM and AF combined sensitization, HDM sIgE levels were distributed in all grades, and AF sIgE levels were mainly in grades 1, 2, and 3. Conclusion: The positive rate of HDM combined with AF was higher in patients with respiratory allergic diseases such as asthma, allergic rhinitis, and allergic rhinitis combined with asthma, suggesting that clinical attention should be paid to the combination of HDM and AF in patients with asthma and allergic rhinitis, especially adults, more likely to be combined with AF.

Serine Metabolism Controls Dental Pulp Stem Cell Aging by Regulating the DNA Methylation of p16

To investigate the characteristics and molecular events of dental pulp stem cells (DPSCs) for tissue regeneration with aging, we isolated and analyzed the stem cells from human exfoliated deciduous teeth (SHED) and permanent teeth of young (Y-DPSCs) and old (A-DPSCs) adults. Results showed that the stemness and osteogenic differentiation capacity of DPSCs decreased with aging. The RNA sequencing results showed that glycine, serine, and threonine metabolism was one of the most enriched gene clusters among SHED, Y-DPSCs, and A-DPSCs, according to analysis based on the Kyoto Encyclopedia of Genes and Genomes. The expression of serine metabolism-related enzymes phosphoserine aminotransferase 1 (PSAT1) and phosphoglycerate (PHGDH) decreased in A-DPSCs and provided less methyl donor S-adenosylmethionine (SAM) for DNA methylation, leading to the hypomethylation of the senescence marker p16 (CDNK2A). Furthermore, the proliferation and differentiation capacity of Y-DPSCs and SHED decreased after PHGDH siRNA treatment, which reduced the level of SAM. Convincingly, the ratios of PSAT1-, PHGDH-, or proliferating cell nuclear antigen-positive cells in the dental pulp of old permanent teeth were less than those in the dental pulp of deciduous teeth and young permanent teeth. In summary, the stemness and differentiation capacity of DPSCs decreased with aging. The decreased serine metabolism in A-DPSCs upregulated the expression of p16 via attenuating its DNA methylation, resulting in DPSC aging. Our finding indicated that serine metabolism and 1 carbon unit participated in stem cell aging, which provided new direction for stem cell aging study and intervention.

Nicotinamide Increases Intracellular NAD+ Content to Enhance Autophagy-Mediated Group A Streptococcal Clearance in Endothelial Cells

Group A streptococcus (GAS) is a versatile pathogen that causes a wide spectrum of diseases in humans. Invading host cells is a known strategy for GAS to avoid antibiotic killing and immune recognition. However, the underlying mechanisms of GAS resistance to intracellular killing need to be explored. Endothelial HMEC-1 cells were infected with GAS, methicillin-resistant Staphylococcus aureus (MRSA) and Salmonella Typhimurium under nicotinamide (NAM)-supplemented conditions. The intracellular NAD⁺ level and cell viability were respectively measured by NAD⁺ quantification kit and protease-based cytotoxicity assay. Moreover, the intracellular bacteria were analyzed by colony-forming assay, transmission electron microscopy, and confocal microscopy. We found that supplementation with exogenous nicotinamide during infection significantly inhibited the growth of intracellular GAS in endothelial cells. Moreover, the NAD⁺ content and NAD⁺/NADH ratio of GAS-infected endothelial cells were dramatically increased, whereas the cell cytotoxicity was decreased by exogenous nicotinamide treatment. After knockdown of the autophagy-related ATG9A, the intracellular bacterial load was increased in nicotinamide-treated endothelial cells. The results of Western blot and transmission electron microscopy also revealed that cells treated with nicotinamide can increase autophagy-associated LC3 conversion and double-membrane formation during GAS infection. Confocal microscopy images further showed that more GAS-containing vacuoles were colocalized with lysosome under nicotinamide-supplemented conditions than without nicotinamide treatment. In contrast to GAS, supplementation with exogenous nicotinamide did not effectively inhibit the growth of MRSA or S. Typhimurium in endothelial cells. These results indicate that intracellular NAD⁺ homeostasis is crucial for controlling intracellular GAS infection in endothelial cells. In addition, nicotinamide may be a potential new therapeutic agent to overcome persistent infections of GAS.

[Preliminary study of auditory cortex resting-state fMRI features for adult post-lingual deafness]

Objective: To understand the auditory cortex resting-state fMRI features for adult post-lingual deafness.Method: The author performed functional connectivity analysis on the study subjects with resting-state fMRI,the region of interest(ROI) of which were based separately on the left and right sides of primary auditory cortex. The data were collected from 8 cases with severe or above sensorineurally post-lingual deafness,compared to a control group of 8 cases with normal hearing. Result: When ROI were based on the left A1 areas of all subjects, the main activating area in the control group was bilateral superior temporal gyrus(STG), while the post-lingual deafness group included the bilateral STG, pre-central gyri, left Transverse temporal gyrus(TTG), post-central gyri and right TTG (P<0.01); when ROI were based on the right A1 areas of all subjects, the main activating area in the control group was the bilateral STG, while the post-lingual deafness group included the bilateral STG, right precentral gyri and post-central gyr i(P<0.01). The data showed statistical significance(P<0.05). Conclusion: After hearing loss functional reorganization takes place in the brains of adults with post-lingual deafness, resulting in possible enhancement of visual sense, tactile sense and other sensory systems in order to compensate information acquisition in daily life. .

NAD-Glycohydrolase Depletes Intracellular NAD+ and Inhibits Acidification of Autophagosomes to Enhance Multiplication of Group A Streptococcus in Endothelial Cells

Group A Streptococcus (GAS) is a human pathogen causing a wide spectrum of diseases, from mild pharyngitis to life-threatening necrotizing fasciitis. GAS has been shown to evade host immune killing by invading host cells. However, how GAS resists intracellular killing by endothelial cells is still unclear. In this study, we found that strains NZ131 and A20 have higher activities of NADase and intracellular multiplication than strain SF370 in human endothelial cells (HMEC-1). Moreover, nga mutants of NZ131 (SW957 and SW976) were generated to demonstrate that NADase activity is required for the intracellular growth of GAS in endothelial cells. We also found that intracellular levels of NAD+ and the NAD+/NADH ratio of NZ131-infected HMEC-1 cells were both lower than in cells infected by the nga mutant. Although both NZ131 and its nga mutant were trapped by LC3-positive vacuoles, only nga mutant vacuoles were highly co-localized with acidified lysosomes. On the other hand, intracellular multiplication of the nga mutant was increased by bafilomycin A1 treatment. These results indicate that NADase causes intracellular NAD+ imbalance and impairs acidification of autophagosomes to escape autophagocytic killing and enhance multiplication of GAS in endothelial cells.

[Diagnosis and treatment of canal conversion during canalith repositioning procedure for benign paroxysmal positional vertigo]

Objective:To investigate the diagnosis and treatment of canal conversion during canalith repositioning procedure for benign paroxysmal positional vertigo.Method:The clinic features, nystagmus characteristics, diagnosis and treatment of the patients with benign paroxysmal positional vertigo who suffered from canal conversion during canalith repositioning procedure were analyzed retrospectively.All patients'positioning test and canalith repositioning procedure were done with the aid of videonystagmography.Result:A total of 186 patients with benign paroxysmal positional vertigo were diagnosed and performed canalith repositioning procedure.Eight patients (4.3%) developed canal conversion after canalith repositioning procedure.Of these 8 patients,5 cases with posterior canal canalolithiasis converted to lateral canal canalolithiasis,2 cases with lateral canal canalolithiasis converted to posterior canal canalolithiasis,and 1 case with posterior canal canalolithiasis converted to anterior canal canalolithiasis. All cases recovered well under the corresponding repositioning procedure.Conclusion:The change of the characteristics of positioning nystagmus is the major diagnostic feature of canal conversion. Accurate diagnosis and targeted repositioning procedure are the key to the success of canal conversion treatment.

[The analysis of the electrode impedance in different periods after cochlear implantation performed with round window insertion in steroid deposition]

Objective:To study the variation of the electrode impedance in different periods after cochlear implantation performed with round window insertion in steroid deposition, and to provide the basis for the postoperative debugging of the speech processor. Method:Detected the electrode impedance of 47 cochlear receivers after operation in steroid deposition from September 2014 to October 2015, compared the impedance values between different periods, and different groups according to their locations. Result:The average impedance of all the electrodes and the 3 subgroups are low after implantation (period A0), peaked at the first month (period A1), then decreased slowly, and then turned to be stable at the sixth month (period A3); the impedance values were no significantly different between the sixth month (period A3) and the twelfth month (period A4) while were significantly different between each of other two periods (P<0.05); the apical group had the highest impedance and the basal group had the lowest impedance in all the 5 periods. Conclusion:The local use of steroid can decrease the impedance of the electrode after implantation. The impedance value were the low during operation, peaked at the first month, then decreased slowly, and turned to be stable at the sixth month. As a result, the cochlear implant should be debugged at regular intervals in 6 months after operation to obtain the best hearing status.

[Clinical observation on human alpha glucosidase in treatment of five patients with glycogen storage disease Ⅱ]

Objective: To evaluate the effect of enzyme replacement therapy (ERT) on glycogen storage disease typeⅡ(GSDⅡ). Method: The clinical data of three juvenile onset and two infant onset GSDⅡpatients were collected from First Affiliated Hospital of Sun Yat-sen University in October 2015 to July 2016.Patient 1 was female, the age of onset was 15 months. Patient 2 was male, the age of onset was 20 months. Patient 3 was female, the sister of patient 2, the age of onset was 47 months. Patient 4 was male, the age of onset was 5 months. Patient 5 was male, the age of onset was 1 month.The age at the start of ERT of the 5 patients was 32, 31, 56, 34, and 3 months respectively and the duration of ERT was 19, 9, 4, 5, 5 doses respectively.ERT was administered at 20 mg/kg every 2 weeks.Dexamethasone was regularly given before each infusion. Result: ERT was well tolerated, only one time, Patient 1 developed tachycardia and hypertension without using dexamethasone.Patient 2 underwent successfully ventilator weaning.Patient 1 underwent a tracheotomy, also needed mechanical ventilation treatment.Patient 4 noninvasive ventilation was tried. Conclusion: Recombinant human alpha-glucosidase treatment was effective and well tolerated in patients with GSDⅡ.

Adipocytes play an etiological role in the podocytopathy of high-fat diet-fed rats

Obesity is a risk factor that promotes progressive kidney disease. Studies have shown that an adipocytokine imbalance contributes to impaired renal function in humans and animals, but the underlying interplay between adipocytokines and renal injury remains to be elucidated. We aimed to investigate the mechanisms linking obesity to chronic kidney disease. We assessed renal function in high-fat (HF) diet-fed and normal diet-fed rats, and the effects of preadipocyte- and adipocyte-conditioned medium on cultured podocytes. HF diet-fed and normal diet-fed Sprague Dawley rats were used to analyze the changes in plasma BUN, creatinine, urine protein and renal histology. Additionally, podocytes were incubated with preadipocyte- or adipocyte-conditioned medium to investigate the effects on podocyte morphology and protein expression. In the HF diet group, 24 h urinary protein excretion (357.5 ± 64.2 mg/day vs 115.9 ± 12.4 mg/day, P < 0.05) and the urine protein/creatinine ratio were significantly higher (1.76 ± 0.22 vs 1.09 ± 0.15, P < 0.05), increased kidney weight (3.54 ± 0.04 g vs 3.38 ± 0.04 g, P < 0.05) and the glomerular volume and podocyte effacement increased by electron microscopy. Increased renal expression of desmin and decreased renal expression of CD2AP and nephrin were also seen in the HF diet group (P < 0.05). Furthermore, we found that adipocyte-conditioned medium-treated podocytes showed increased desmin expression and decreased CD2AP and nephrin expression compared with that in preadipocyte-conditioned medium-treated controls (P < 0.05). These findings show that adipocyte-derived factor(s) can modulate renal function. Adipocyte-derived factors play an important role in obesity-related podocytopathy.

Evaluation of nasal patency by visual analogue scale/nasal obstruction symptom evaluation questionnaires and anterior active rhinomanometry after septoplasty: a retrospective one-year follow-up cohort study

OBJECTIVE

To assess the efficacy of septoplasty and the correlation between the subjective evaluations of a visual analogue scale (VAS) and the Nasal Obstruction Symptom Evaluation (NOSE) questionnaire and active anterior rhinomanometry of the nasal airway after septoplasty.

DESIGN

A retrospective, individual cohort study.

SETTING

Ear, Nose and Throat Department, Taipei City Hospital, Taipei, Taiwan.

PARTICIPANTS

Fifty patients with chronic nasal obstruction were enrolled in the study. All 50 patients underwent septoplasty because of nasal septal deviation. Another 28 patients without nasal symptoms served as controls.

MAIN OUTCOME MEASURES

VAS, NOSE and active anterior rhinomanometry were used to measure the sensation of nasal obstruction. All measurements were performed in both groups preoperatively and then repeated on three postoperative visits (3, 6 and 12 months).

RESULTS

The mean VAS score, NOSE score and the nasal resistance in the narrow side of the nose in the study group showed reduced symptoms at 3, 6 and 12 months postoperatively compared with the respective preoperative measurements (P < 0.001, all). The VAS and NOSE scores did not significantly correlate with total nasal resistance preoperatively or postoperatively. The VAS and nasal resistance in the obstructed nasal cavity correlated significantly preoperatively (P < 0.05), but not postoperatively.

CONCLUSIONS

The subjective and objective symptoms of nasal obstruction had improved 1 year after septoplasty. A significant correlation between VAS scores and nasal resistance in the narrow side of the nose was found before surgery. The subjective and objective measurements of nasal obstruction lacked significant correlation postoperatively.

(-)-Anonaine induces DNA damage and inhibits growth and migration of human lung carcinoma h1299 cells

The anticancer effects of (-)-anonaine were investigated in this current study. (-)-Anonaine at concentration ranges of 50-200 μM exhibited significant inhibition to cell growth and migration activities on human lung cancer H1299 cells at 24 h, albeit cell cycle analyses showed that (-)-anonaine at the above concentration ranges did not cause any significant changes in cell-cycle distributions. Significant nuclear damages of H1299 cells were observed with 10-200 μM (-)-anonaine treatment in a comet assay, whereas higher concentrations (6 and 30 mM) of (-)-anonaine concentrations were required to cause DNA damages in an in vitro plasmid cleavage assay. In summary, our results demonstrated that (-)-anonaine exhibited dose-dependent antiproliferatory, antimigratory, and DNA-damaging effects on H1299 cells. We inferred that (-)-anonaine can cause cell-cycle arrest and DNA damage to hamper the physiological behavior of cancer cells at 72 h, and therefore, it can be useful as one of the potential herbal supplements for chemoprevention of human lung cancer.

Removal of ammonium from rare-earth wastewater using natural brucite as a magnesium source of struvite precipitation

This paper presents a study regarding ammonium removal from rare-earth wastewater by struvite precipitation with natural brucite mineral as a source of magnesium. Experimental results indicated that a pH ranging from 8.5 to 9.5 was the optimum for the removal of ammonium using the soluble form of brucite as a magnesium source. Additionally, when solid brucite was used as a magnesium source as well as an alkali reagent, the initial ammonium concentration of 4,535 mg/L decreased to 239-317 mg/L after an reaction time of 12 h in wastewater treated with the S/L (solid brucite/liquid wastewater) ratios ranging from 31.2 to 63.2 g/L. Furthermore, as some non-reacted brucite still remained in the precipitates obtained at the end of reaction, the precipitates were subjected to reuse. The reuse results demonstrated that the reuse of the precipitates obtained with 63.2 g/L was feasible, and almost half of the brucite dose could be saved.

Reductions in the effects of damping on stress concentration in premolars by post-endodontic restorations: a non-linear finite element study

The aim of this study was to measure the structural damping constants of premolars after treatment with a cast Co-Cr post-core system or permanent root filling, and to evaluate the stress damping effects of these restored premolars. Both the damping ratio and the natural frequency (NF) of the cast Co-Cr post-core restored premolars and the permanent root-filled premolars were detected by in-vitro NF testing experiments. Unprepared premolars served as the control. The damping constants beta of the samples were calculated from the measured damping ratios and natural frequencies. The measured damping constants beta of the test premolars were then used for dynamic finite element (FE) analyses. Stress contours and damping effects of stresses in each treated type of premolar were computed and compared using ANSYS. The measured damping constants beta were 0.75 x 10(-5) for the unprepared premolars, 0.69 x 10(-5) for the root-filled premolars with coronal restoration, and 0.72 x 10(-5) for the cast Co-Cr post-core restored premolars. The unprepared intact premolars demonstrated the highest stress dissipation effects with a ratio of 29.3 per cent at the middle root opposite to the loading side. However, no stress dissipation effects were found in the premolars that had been restored with the cast Co-Cr post-core system. The FE analysis showed that metallic post treatment attenuated the damping properties of the premolar. The effects of damping on stress concentration were significantly lower in restored premolars than in untreated vital premolars. These findings suggest that future research on post material should take the damping property into consideration.

Recycle use of magnesium ammonium phosphate to remove ammonium nitrogen from rare-earth wastewater

This paper presents a recycle MAP process (magnesium ammonium phosphate) to remove NH4-N from a typical rare-earth wastewater. The optimum conditions for the MAP precipitation and recycle use of the MAP with a newly-designed process were investigated in laboratory. The results showed that the pH value and dosages of P (phosphate) and Mg reagents have a significant influence on NH4-N removal, with a maximum removal efficiency of 99.4% at the conditions of pH=9 and Mg:N:P molar ratio=1.2:1:1.2. In the process of recycle use of the MAP, adding some HCl to dissolve MAP decomposition residues could effectively enhance NH4-N removal. The NH4-N removal efficiency reached 99.6% by adding an HCl amount of H+:OH- molar ratio=0.8 into the reused MAP decomposition residues, whereas the NH4-N removal efficiency without addition of HCl was only 96.4%. Moreover, the residual PO4-P from the end of reaction was recovered and the optimum recovery efficiency was achieved at a Mg:P molar ratio=6 and pH=10. Under these optimum conditions, the residual NH4-N and PO4-P concentrations in the treated wastewater, through 6 times of the recycling, were less than 15 mg/L and 1 mg/L, respectively. On the basis of this, an economic evaluation of the recycling MAP was made, and this recycle process could save 48.6% cost used in the chemicals for treating per cubic meter of the rare-earth wastewater, compared to the conventional MAP process.

Design of a stability-detecting device for dental implants

Resonance frequency (RF) analysis technology was used to design a dental implant stability detector. The device uses a miniature-sized electromagnetic triggering rod to elicit vibration in a dental implant. Vibrational signals were recorded via an acoustic receiver. To assess the in vivo performance of the test apparatus, animal models were used. Implants were placed in the left tibia of 12 rabbits using a conventional surgical procedure. Standard 3.2 mm × 8 mm implants were placed in each test tibia with pre-tapping cavities of 3.2 mm and 3.7 mm diameters to simulate either a ‘well-fitting’ or a ‘loosely fitting’ situation. The RF values of the test implants were detected by the newly developed device which was directly mounted on the healing abutments of the implants. The results showed that the RF values of the implants under well-fitting conditions significantly increased (p<0.01) 3 weeks after surgery and reached a plateau at around 6-7 weeks. Meanwhile implants with higher initial RF values had shorter healing times and higher final RF values at the plateau. Based on these findings, it was concluded that the idea of using the current designed device for detecting the degree of bone healing during the osseointegration process seems feasible.

Natural frequency assessment of stability of root keeper magnetic devices

The aim of the study was to evaluate the potential for using natural frequency (NF) as an indicator for assessing the stability of a magnetic keeper device used in prosthodontic treatment. A three-dimensional finite element (FE) model of a root keeper-cement-dentine system was established for NF analysis. The model was first validated against a series of in vitro experiments. Then, NF values of the first vibrational mode of the FE model with various boundary conditions were calculated. The in vitro results showed that the measured NF values of the root keeper-incisor units decreased significantly (p<0.01) from 9.07 +/- 0.37 to 5.73 +/- 0.10 kHz when the units were embedded in simulated bony tissue. Results obtained from FE simulations demonstrated that the root keeper would fully loosen when the constant values of the spring elements were lower than 10(4) N-m(-1). Furthermore, a linear increase in the NF values of the model was observed from 6.16 to 15.52 kHz, when the constant was increased from 10(4) to 10(7) N-m(-1), and the values then reached a plateau. The results indicate that the NF value of a root keeper has the potential to be used for monitoring the stability of such a device.

[Gene cloning, construction and expression of single-chain Fv (scFv) against the membrane protein of Schistosoma japonicum]

OBJECTIVE

To construct single chain antibody specific to membrane protein of Schistosoma japonicum by genetic engineering technique.

METHODS

The VH (heavy-chain variable region) and VL(light-chain variable region) genes were amplified by PCR from the genomic DNA of NP11-4 cell line, and sequenced by Sanger's method. The ScFv was constructed in pTHA90 vector using VH and VL genes, then expressed by IPTG.

RESULTS

The VH and VL genes were obtained through PCR. The DNA sequences showed that VH and VL were new variable region genes of antibody. They were registered by GenBank. A ScFv gene with (Gly4Ser) 3 intralinker in the pTHA90 vector was successfully constructed. The ScFv was expressed as thioredoxin-fused proteins about 36.2 kDa.

CONCLUSION

A specific ScFv against the membrane protein of Schistosoma japonicum was constructed and expressed.

Growth inhibitory activity of lemnabourside on human prostate cancer cells

Induction of apoptosis and androgen ablation are two major approaches for treating human prostate carcinoma. In a study of the bioactive components of the soft coral Nephthea chabroli, we found that lemnabourside is a 5alpha-reductase inhibitor, as shown by its ability to inhibit the conversion of testosterone into the more potent dihydrotestosterone in rat prostate homogenate. The compound also inhibited the incorporation of tritiated thymidine into human prostate androgen-dependent carcinoma LNCaP cells, and thus blocking the cell proliferation (IC50 = 37.5 microM). The expression of prostate marker genes, including 5alpha-reductase, prostate-specific antigen, prostatic acid phosphatase and androgen receptor, and the anti-apoptotic bcl-2 gene were markedly reduced, but the transcription of apoptosis-related caspase 3 gene showed a dose-dependent increase in lemnabourside-treated LNCaP cells. Immunofluorescent microscopy and flow cytometric analysis further demonstrated apoptotic changes in these cells. Taken all results together, a relatively weak 5alpha-reductase inhibitory activity on LNCaP cells (EC50 > 250 microM), and a similar growth inhibitory activity on both androgen dependent- and independent-prostate cells (IC50 approximately 37.5 microM) indicated that caspase-3 apoptosis pathway is one of the possible antiproliferative activities mediated by lemnabourside.

Assessment of membrane potentials of mitochondrial populations in living cells

Mitochondrial membrane potentials (MMP) reflect the functional status of mitochondria within cells. Fluorescent probes to estimate these potentials within cells have been available for some time, but measurements of populations of mitochondria are not possible by existing methods. Therefore, comparisons between different cell types (e.g., fibroblasts and neuroblastoma), fibroblast cell lines from different patients, or even the same cell following various experimental paradigms are not feasible. The current approach estimates populations of MMP within living cells at 37 degrees C using the combination of conventional fluorescence microscopy and three-dimensional deconvolution by exhaustive photon reassignment. With this method, raw images are acquired rapidly with low-intensity (nonlaser) light with minimal concentrations of fluorescent dye. The method uses the fluorescent dye tetramethylrhodamine methyl ester, which equilibrates in cells according to the Nernst equation and provides a numerical, replicable estimate of MMP for populations of cellular mitochondria. This method can detect either increases or decreases in MMP as small as 5%. Furthermore, MMP in different cell types appear distinct. Values in fibroblasts (-105 +/- 0.9 mV) and N2a cells (-81 +/- 0.7 mV) were very different by this method. This approach bridges investigations of individual mitochondria to those that assess MMP by examining global fluorescence from cells.

Natural frequency analysis of periodontal conditions in human anterior teeth

The purpose of this study was to evaluate the possibility of using natural frequency (NF) analysis to detect the attachment loss of periodontal tissue. In this study, 698 anterior teeth were examined by a conventional probing method and also by NF analysis. The teeth were triggered to vibrate with an impulse hammer, and the vibrational response was detected by an acoustic sensor. Our results demonstrate no significant difference in NF values between the upper-lower/left-right quadrants of the tested teeth, although the mean natural frequency value of central incisors with periodontal disease was found to be 1.24 +/- 0.11 kHz which is significantly lower than that of teeth in a healthy condition (1.34 +/- 0.20kHz; p < 0.01). On the other hand, the mean frequency for periodontal disease involving canines (1.28 +/- 0.09 kHz) was also significantly lower than the corresponding value for healthy analogs (1.35 +/- 0.17 kHz; p < 0.05). These results suggest that NF analysis appears to be an effective method for assessing the periodontal condition of anterior teeth. Moreover, since this method is noninvasive, nondestructive, and necessitates minimal tooth contact, it can serve as an effective method for the early quantifiable testing and prevention of periodontal disease.

Microsized 2D protein arrays immobilized by micro-stamps and micro-wells for disease diagnosis and drug screening

A novel method of protein array immobilization, using micro stamps to pick up proteins from micro wells and deposit them on to a bio-absorption chip, has been developed. This method can potentially transfer several protein spots on to an organized array for applications such as disease diagnosis and drug screening by parallel biological or chemical processes. Fabrication of the micro stamp and the micro well arrays involves thick-photoresist lithography, bulk micromachining, and a molding process, whereas fabrication of the bio-absorption chip involves amino-modification by use of APTS (aminopropyItrimethoxysilane) and surface activation by use of BS3 (bis-sulfosuccinimidyl suberate). Successful transfer of protein on to the bio-absorption surface using the micro stamp-well array has been demonstrated. The size variation between different stamping spots has been shown to be less than 10%, and the APTS-BS3 surface has also been proved to bind the protein efficiently. Appreciable protein retention was achieved during 6-h washing, which shows the binding strength of the bio-absorption surface is sufficient for protein processing.

Auditory abnormalities associated with unilateral renal agenesis

OBJECTIVE

To evaluate the relationship between unilateral renal agenesis and auditory abnormality, and to determine the clinical spectrum of hearing impairment in such patients.

METHODS

Seventy-five children with unilateral renal agenesis underwent auditory examinations. The subjects comprised 35 males and 40 females. Fourteen females had mullerian abnormalities. Another 75 schoolchildren with the same gender profile were selected for audiometric testing as a control group. Children with sonographically evident urogenital system abnormalities were excluded from the control group.

RESULTS

The prevalence of auditory abnormalities in children with unilateral renal agenesis (4/75) (5.3%) was higher than in the control group (0%). The prevalence in children with urogenital anomalies was significantly higher in patients with renal agenesis than in the normal population (28.5%). Audiometric results showed that four of the 75 children manifested ipsilateral sensorineural hearing impairment, particularly in the high-frequency range. All were females with coexisting genital abnormalities. Two were diagnosed with mild sensorineural hearing impairment while the other two had moderate hearing loss.

CONCLUSIONS

The results of our study suggest that neurosensory hearing loss was found to be associated with renal agenesis. Further audiometric follow-up of children with renal agenesis seems worthwhile.

Flexural behaviour of post-cured composites at oral-simulating temperatures

Post-curing treatments have been known to improve the mechanical stability of visible light-cured composites. After individual post-curing treatment, the flexural strength (FS) of four commercial direct/indirect placement composite materials which differ greatly in composition [oligocarbonate dimethacrylate (OCDMA)-based Conquest C & B (CQT), Bisphenol-A glycidyl dimethacrylate (BisGMA)-based Charisma, urethane dimethacrylate (UDMA)-based Concept (CCT), and BisGMA/UDMA-based Dentacolor] was evaluated under water in the temperature range of 12-50 degrees C. A control series was tested in air at room temperature (25 +/- 1 degrees C). Data were analysed using ANOVA and Duncan's test. Flexural strengths overall decreased (20-40%, P < 0.01) with increasing temperatures except with Conquest C & B. Surprisingly, higher FS values were found in wet conditions than in dry conditions at 25 degrees C. UDMA-based materials much more easily undergo softening in water and by temperature change than do BisGMA- or OCDMA-based materials. Post-cured composites can be significantly affected by exposure to oral environments. Different composition determines the degree of influence.

Dichloroacetate exerts therapeutic effects in transgenic mouse models of Huntington's disease

Dichloroacetate (DCA) stimulates pyruvate dehydrogenase complex (PDHC) activity and lowers cerebral lactate concentrations. In the R6/2 and N171-82Q transgenic mouse models of Huntington's disease (HD), DCA significantly increased survival, improved motor function, delayed loss of body weight, attenuated the development of striatal neuron atrophy, and prevented diabetes. The percentage of PDHC in the active form was significantly reduced in R6/2 mice at 12 weeks of age, and DCA ameliorated the deficit. These results provide further evidence for a role of energy dysfunction in HD pathogenesis and suggest that DCA may exert therapeutic benefits in HD.

Dehydroepiandrosterone inhibits lipopolysaccharide-induced nitric oxide production in BV-2 microglia

Levels of dehydroepiandrosterone (DHEA) and its sulfated derivative (DHEAS) decline during aging and reach even lower levels in Alzheimer's disease (AD). DHEA is known to exhibit a variety of functional activities in the CNS, including an increase of memory and learning, neurotrophic and neuroprotective effects, and the reduction of risk of age-related neurodegenerative disorders. However, the influence of DHEA on the immune functions of glial cells is poorly understood. In this study, we investigated the effect of DHEA on activated glia. The production of inducible nitric oxide synthase (iNOS) was studied in lipopolysaccharide (LPS)-stimulated BV-2 microglia, as a model of glial activation. The results showed that DHEA but not DHEAS significantly inhibited the production of nitrite in the LPS-stimulated BV-2 cell cultures. Pretreatment of BV-2 cells with DHEA reduced the LPS-induced iNOS mRNA and protein levels in a dose-dependent manner. The LPS-induced iNOS activity in BV-2 cells was decreased by the exposure of 100 microM DHEA. Moreover, DHEA suppressed iNOS gene expression in LPS-stimulated BV-2 cells did not require de novo synthesis of new proteins or destabilize of iNOS mRNA. Since DHEA is biosynthesized by astrocytes and neurons, our findings suggest that it might have an important regulatory function on microglia.

[Construction, expression and activity test of a reshaping single-chain antibody against human CD3]

Monoclonal antibody (McAb) against human CD3 can adjust human body's immune statement in various ways, so that its clinical potential is highly regarded. In order to overcome the immunogenecity related to the murine McAb, this research effort was focused on constructing a reshaping single-chain antibody(scFv) against human CD3 employing antibody engineering. First, the CDRs of the murine McAb against human CD3 OKT3 was transplanted into the light-chain framework regions (FRs) of human McAb LS1 and the heavy-chain FRs of human McAb Nd respectively, spatial conformation was predicted by computer analysis. Then some particular residues were replaced in FRs basing on the result of conformational prediction to draw out the amino acid sequences of the reshaped VL and VH. The genes were chemically synthesize and inserted into an expression vector pROH80 to construct the reshaping scFv. Inducing the expression of reshaping scFv, the products are mainly as inclusion bodies. The reshaping scFv was expressed in another vector pALM. The inclusion bodies were denatured and then renatured by gel filtration. The renatured products were purified by immobilized metal affinity chromatograph (IMAC). Finally, the antigen-binding activily of the reshaping scFv against human CD3 was testified by the Compelitire in hibilory fluorescenceactivated cell sorting (FACS). The competitive inhibition rate is 18%.

Factors influencing the dynamic behaviour of human teeth

Modal analysis is carried out to test the natural frequencies of certain human teeth, including central incisors (CIs), canines (CAs), first premolars (FPs) and first molars (FMs). A total number of 1007 teeth are tested, taking into account tooth type, oral location, age and gender, to analyse the effects of the above-mentioned factors on the natural frequency of the sample teeth. The results reveal that no significant difference in the natural frequency is noted among teeth in the four different intra-oral quadrants. Nevertheless, tooth type and age elicit an effect upon the value of the natural frequency of teeth. On the other hand, the mean value for the natural frequency of CIs (1.27 +/- 0.15 kHz), CAs (1.30 +/- 0.15 kHz), FPs (1.27 +/- 0.15 kHz) and FMs (1.16 +/- 0.12 kHz) for males are significantly lower (p < 0.01) than the analogous figure for females (1.41 +/- 0.21 kHz for CIs, 1.40 +/- 0.18 kHz for CAs, 1.37 +/- 0.20 kHz for FPs, and 1.25 +/- 0.16 kHz for FMs). Moreover, the natural frequency of teeth in male subjects varies with age (p < 0.05). The highest mean frequency of CIs, CAs and FPs for the male subjects is found for the group aged between 40 and 49 years. On the other hand, the natural frequency for the similar set of teeth for the female subjects is shown to be in no way associated with age.

Giant ethmoid osteoma with orbital extension, a nasoendoscopic approach using an intranasal drill

OBJECTIVE

Ethmoid osteoma is a slow-growing, benign, and encapsulated bony tumor. Symptoms occur earlier than with osteomas of the frontal sinus because of the small volume of the ethmoid sinus. Interestingly, orbital extension is uncommon. Treatment remains controversial, with open procedures typically being used. In this article, we present a less invasive yet safe and effective approach to treatment.

STUDY DESIGN

A nasoendoscopic approach using a Stammberger-Saches intranasal drill was developed for treatment of patients with ethmoid osteoma, with or without orbital extension. Between 1995 to 1999, seven patients underwent the new surgical procedure.

METHODS

All procedures were performed under general anesthesia. Using 0 degrees and 30 degrees endoscopes, surface anesthesia of the nasal mucosa was performed, the anterior ethmoid cell was resected, and the whitish osteoma found. The osteoma was drilled out inferolaterally to superomedially. In the patient with orbital extension, a double-ended blunt elevator was used to separate the remaining osteoma from the lamina papyracea and to push the residual osteoma medially toward the nasal septum. With alternate drilling and elevation, the osteoma was gently removed. The surgical site was then packed.

RESULTS

The method successfully treated all patients. There were no major complications. The single patient with orbital extension had mild postoperative periorbital ecchymoses. Nasoendoscopy showed normal epithelialization 4 to 6 weeks after surgery. Computed tomography showed no residual tumors 6 months after surgery.

CONCLUSION

The 30 degrees nasoendoscopic approach using an intranasal drill provides a good operative field and is a safe and effective technique, with the potential to become the treatment of choice in selected cases.

Resveratrol inhibits interleukin-6 production in cortical mixed glial cells under hypoxia/hypoglycemia followed by reoxygenation

Reactive oxygen intermediates (ROIs) are important mediators of a variety of pathological processes, including inflammation and ischemia/reperfusion injury. Cytokines and chemokines are detected at mRNA level in human and animal ischemic brains. This suggests that hypoxia/reoxygenation may induce cytokine production through generation of ROIs. In this study, we investigated the cytokine induction and inhibition by antioxidants in rat cortical mixed glial cells exposed to in vitro ischemia-like insults (hypoxia plus glucose deprivation). The results showed that interleukin-6 (IL-6) mRNA and protein, but not tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta (IL-1beta), were induced during hypoxia/hypoglycemia followed by reoxygenation in the mixed glial cells. The accumulation of IL-6 mRNA was induced as early as 15 min after hypoxia/hypoglycemia and its level was further increased after subsequent reoxygenation. Among the antioxidants studied, only resveratrol suppressed IL-6 gene expression and protein secretion in mixed glial cultures under hypoxia/hypoglycemia followed by reoxygenation. These findings suggest that resveratrol might be useful in treating ischemic-induced inflammatory processes in stroke.

Thermo-debonding mechanisms in dentin bonding systems using finite element analysis

The finite element method (FEM) has been extensively used in evaluating the interfacial status of biomaterials. We used FEM to explore the microscopic debonding mechanism of the dentin/hybrid layer/resin adhesive interface. The stress status of the local material was used as an index to judge whether the adhesive interface would develop a debonding mechanism. To generate the local stress concentration, the thermal boundary condition was applied to the model which has the phenomenon of the coefficient of thermal expansion (CTE) mismatch. The thermal boundary condition was used to emulute a previous study conducted with a laser thermoacoustic technique (LTAT). The materials, Scotchbond MP, Optibond, and Tenure bonding systems, used in the previous experiment were also tested in this study. The results show that interfacial debonding in the finite element model occurred through the hybrid layer for both the Scotchbond MP and Tenure systems, as well as within the adhesive layer itself for the Optibond system. These findings are compatible with observations by SEM obtained by LTAT. Another transformed model was created to test the "elastic cavity wall" concept. The result also confirms the importance of the elastic cavity wall concept. These compatible results between FEM and LTAT indicate that FEM can be a very useful supplement to thermoacoustic testing.

Effect of temperature and flux concentration on soldering of base metal

The present study used the acoustic emission (AE) technique to evaluate interactions among soldering temperature, flux treatment, and the resultant ultimate tensile strength (UTS). Scanning electron microscopy (SEM) was used to examine fracture surfaces of the solder joints. Specimens were cast from removable partial denture alloy and then placed in a jig with a gap distance of 1.0 mm. A high-frequency soldering machine with an optical pyrometer was used for soldering at 1150 degrees C and 1200 degrees C, respectively. The flux concentrations were 67% and 75%. The soldered specimens were subjected to tensile test at a crosshead speed of 0.05 mm/min. During testing, acoustic emissions in the frequency range of 100--1200 kHz were collected, filtered, recorded, and processed by a sensing device. The results were analysed by ANOVA and Tukey LSD test. UTS at different temperatures showed no significant difference according to either mechanical or acoustic results. But in the 1200 degrees C group, the UTSs and AE counts showed significant differences (P<0.05) at both flux concentrations. SEM showed that the 1200C group had better dendritic crystal structure than did the 1150 degrees C group. In the 1200 degrees C group specimens with 67% flux had fewer flux inclusion bodies and dendritic crystals than did specimens with 75% flux. The 75% flux subgroup produced high-amplitude (60--70 dB) acoustic signals within the elastic deformation zone, while the 67% flux subgroup produced similar signals within the plastic deformation zone, either beyond the 0.2% yield point or before fracture.

Influence of silanization and filler fraction on aged dental composites

The effect of silanization and filler fraction on the mechanical properties of aged dental composites was investigated. Experimental composites (75/25 Bis-GMA/TEGDMA resin reinforced with 0, 12.6, 30.0, and 56.5 vol% 8 microm silanized/unsilanized BaSiO6) were fabricated into 4.7 mm diameter x 2.2 mm thick discs and 3.5 mm diameter x 7.3 mm thick discs for diametral tensile and compressive tests, respectively. The effect of immersion in 75% ethanol at 37 degrees C for 0-30 days on the diametral tensile strength (DTS) and compressive strength (CS) of the samples was evaluated and analysed by ANOVA and Tukey LSD test. The fracture interface between filler and resin matrix was then examined by scanning electron microscope. Results and subsequent statistical evidence from DTS (18.6+/-7.6 MPa, silanized versus 11.7+/-2.6 MPa, unsilanized) and CS (85.1+/-29.7 MPa, silanized versus 56.0+/-11.3 MPa, unsilanized) strongly implies that silanization may greatly enhance the mechanical properties of the resin composites. Furthermore, it also shows that both DTS and CS increased proportionally as the filler fraction of the composites increased. However, in the unsilanized groups, DTS decreased (up to 40%) as the filler fraction increased, and CS showed no relevance to the filler fraction at all. As for the influence of aging, it was found that both DTS and CS showed a significant decrease after immersion in 75% ethanol, and silanization heavily correlated with the filler fraction of aged-resin composites. Microscopic examination of the fractured samples showed that failure primarily occurred within the resin matrix per se for silanized composites and adjacent to the filler particles for unsilanized composites. All the evidence points to the conclusion that mechanical properties of aged-resin composites can be greatly influenced by silanization and the filler fraction.

Stress analysis of different wall thicknesses of implant fixture with various boundary levels

The aim of the present work is to develop 3D finite element models of implant fixture with different wall thicknesses to predict maximum stress concentration sites and distribution contours after loading. A maximum lateral force of 150 N was applied to simulate horizontal occlusal forces. When the fixtures were constrained to simulate different boundary levels, the maximum equivalent stress (max EQV) was always located at the implant-bone interface. Max EQV increased when the wall thickness or boundary level was reduced to a certain extent. The fixture with a wall thickness of 0.97 mm demonstrated the smallest stress increase ratio when the boundary level was lowered. Our results indicated that both wall thickness and the boundary level played important roles in maintaining a well-distributed stress level within the fixture. The stress concentration decreased when the fixture wall became thicker, however, this effect was less significant when the surrounding bone level was reduced.

Induction of cytokine genes and IL-1alpha by chemical hypoxia in PC12 cells

The role of cytokine in neuronal injury was examined in rat pheochromocytoma (PC12) cells under chemical hypoxia (i.e. KCN) and glucose deprivation. The mRNA levels of interleukin-1alpha (IL-1alpha), IL-6, and tumor necrosis factor-alpha (TNF-alpha) were measured by reverse transcription-polymerase chain reaction (RT-PCR) in PC12 cells exposed to 0.5 mM KCN for various time intervals. Cytokine mRNA levels expressed to peak levels 30 minutes after KCN treatment and declined gradually until 240 min. The IL-1alpha activity reached the highest levels 2 hr after the same KCN treatment. Under parallel conditions, KCN increased cytosolic free calcium concentration ([Ca2+]i) in the absence of glucose. However, IL-1alpha mRNA induction by KCN was not altered under calcium-free conditions in PC12 cells, indicating its induction was Ca2+-independent. However, the phosphatidylcholine (PC)-specific phospholipase C (PLC) inhibitor D609 decreased the KCN-induced IL-1alpha mRNA and protein in PC12 cells suggests that PC-PLC might play a role in cytokine induction during hypoxia.

Isothermal Titration Microcalorimetric Studies of the Effect of Temperature on Hydrophobic Interaction between Proteins and Hydrophobic Adsorbents

This study attempted to comprehend how temperature affects hydrophobic interaction between proteins and hydrophobic adsorbents. By equilibrium batch analysis, we measured the adsorption isotherm to evaluate the protein-adsorbent affinity, while isothermal titration calorimetry was used to measure the adsorption enthalpy. In addition, the affinity and enthalpy differences between two proteins, alpha-chymotrypsinogen A and trypsinogen, with two adsorbents, butyl-Sepharose and octyl-Sepharose gel, under varying temperatures were studied with respect to the exposed hydrophobic segments of the protein and ligand hydrophobicity. The enthalpies obtained in this investigation can be used to more thoroughly understand the hydrophobic interaction between proteins and adsorbents. First, the adsorption isotherm experiments reveal that the adsorption quantity of the proteins with the Sepharose gels increases with temperature. For a microcalorimetric measurement, as temperature is increased from 298 to 310 K, the DeltaH value of alpha-chymotrypsinogen A with butyl-Sepharose increases, while the DeltaH value of trypsinogen is reduced. This is likely due to the fact that alpha-chymotrypsinogen A has a higher area of exposed hydrophobic segments than trypsinogen does. This observation also implies that as temperature increases, the interaction mechanism of alpha-chymotrypsinogen A with butyl-Sepharose changes from an adsorption-dominated process to a partitioning process. In addition, for octyl-Sepharose, the DeltaH value of alpha-chymotrypsinogen A is positive and decreases with temperature increment. However, the DeltaH value of trypsinogen was positive and increased with temperature. Therefore, we conclude that as temperature increases, the interaction mechanism of the proteins for octyl-Sepharose is a partitioning-dominated process. Copyright 2000 Academic Press.

Acoustic emissions generated in aged dental composites using a laser thermoacoustic technique

The heating up of dental composites by laser will produce acoustic emissions (AEs) that may be related to fracture mechanisms in the composites. It has been proved that the mechanical properties of dental composites are affected by storage in food simulating liquids, i.e. 75% ethanol, which has a solubility parameter approximating to that of bisphenol glycidyl dimethacrylate (BisGMA) resin. A new method was innovated to evaluate the laser-induced AEs in dental composites aged by 75% ethanol solution. Model systems (50/50 BisGMA/TEGDMA resin filled with 0% and 75 wt.% 5-10 microm silanized BaSiO6) as well as three commercial composites (Marathon One, Z100 and Herculite XRV) were used in this study. Nine samples acting as the control group were tested to establish the correlation of AEs to laser power. The effect of ageing by immersion in 75% ethanol on AEs and diametral tensile strength (DTS) was then evaluated. A quasi-continuous wave CO2 laser was used to heat up the composites. AEs of frequency 100-200 kHz were collected, filtered, recorded and processed using a 4610 Smart Acoustic Monitor. Burst patterns, which formally were assumed to be correlated to fracture mechanisms, were also identified from the data obtained at laser power > or = 5 W for commercial composites and > or = 4 W for model systems. Higher laser powers cause the AE to increase for all composites except unfilled model resin. AEs as a function of power for all aged systems were flat (< 100 events) below 4 W. Emissions then rose sharply to > 1000 events at 7.1 W. Statistically significant differences were found between the AEs obtained at 5 W (commercial composites) and those at 4.3 W (model systems) for material systems and storage times. Marathon One was less affected by the laser and an abrupt change in AE was found between days 0 and 7 of storage for all commercial composites. The AE value from the unfilled model resin was found to be significantly different from that of the model composites. However, they showed an increase in AEs with length of storage time, which was inversely associated with the decreased tendency of their immersed DTS values. Laser-induced AEs may be a valuable adjunct to conventional mechanical testing.

Mcl-1 is a common target of stem cell factor and interleukin-5 for apoptosis prevention activity via MEK/MAPK and PI-3K/Akt pathways

Stem cell factor (SCF) has been suggested as essential for optimal production of various hematopoietic lineages mainly because of its apoptosis prevention function when it costimulates with other cytokines. However, the underlying mechanism of this synergism of apoptosis prevention is largely unknown. The present study examined the expression of some Bcl-2 family members, including Bcl-2, Bcl-X(L), Mcl-1, and Bax, in response to cytokine stimulation in TF-1 and JYTF-1 cells in which SCF costimulation is differentially required for optimal proliferation. The results revealed that only the expression of Mcl-1 highly correlated with the antiapoptotic activity of interleukin-5 (IL-5) and the synergistic effect of SCF. In TF-1 cells, the defect of IL-5 in apoptosis suppression and Mcl-1 induction was associated with the incapability to highly phosphorylate Janus kinases (JAK1, JAK2), signal transducer and activator of transcription-5 (STAT5), mitogen-activated protein kinase (MAPK), and Akt/PKB, whereas SCF costimulation restored the potent phosphorylation of MAPK and Akt/PKB, but not STAT5. The importance of MAPK and Akt/PKB signaling pathways in regulating the expression of Mcl-1 and cell survival was further supported by the observation that inhibition of MEK by PD98059 or phosphatidylinositol-3 kinase (PI-3K) by LY294002 independently resulted in the reduction of Mcl-1 expression and loss of cell viability. Therefore, the data suggest that Mcl-1 is a common antiapoptotic target of both early-stage cytokine SCF and late-stage cytokine IL-5. Both MEK/MAPK and PI-3K/Akt signaling pathways are essential in the regulation of Mcl-1 expression and apoptosis prevention. (Blood. 2000;96:1764-1771)

Assessing the implant/bone interface by using natural frequency analysis

OBJECTIVE

A number of techniques have been proposed for detecting the stability of dental implants. However, the clinical applicability of those methods is still limited. The purpose of this study was to evaluate a new innovative, noninvasive, minimum-contact method for the stability assessment of dental implants.

STUDY DESIGN

Natural frequency is a physical property of a structure, which is strongly related to its boundary conditions. In this study, a modal testing technique was carried out to measure the natural frequency of dental implants. The implants were fixed by a metal clamp stand and were excited to vibrate by an impulse hammer. A noncontact piezoelectric microphone then acoustically acquired the vibration responses of the implants. Natural frequencies of the tested implants were recorded under various clamping forces and clamping levels.

RESULTS

Natural frequencies of the tested implants were concentrated from 8 to 19 kHz under different boundary conditions. On the other hand, the natural frequency values decreased when boundary levels and boundary force were reduced. Linear relationships (P <.005) were found between response frequencies and the degree of implant stability.

CONCLUSIONS

Our results show that the boundary status of an implant can be monitored by detecting its natural frequency. A noncontact transducer used in this study can also serve as a useful tool for future clinical investigations.

Differential alteration of catecholamine release during chemical hypoxia is correlated with cell toxicity and is blocked by protein kinase C inhibitors in PC12 cells

Release of neurotransmitters, including dopamine and glutamate, has been implicated in hypoxia/ischemia-induced alterations in neuronal function and in subsequent tissue damage. Although extensive studies have been done on the mechanism underlying the changes in glutamate release, few have examined the mechanism that is responsible for the changes in catecholamines. Rat pheochromocytoma-12 (PC12) cells synthesize, store, and release catecholamines including DA and NE. Therefore, we used HPLC and ED to evaluate extracellular DA and NE concentrations in a medium during chemical hypoxia in PC12 cells. Chemical hypoxia produced by KCN induced differential release of DA and NE. Under normal glucose conditions, KCN induced release of NE, but not DA. Under glucose-free conditions, KCN-induced release of DA was elevated transiently, whereas the release of NE increased progressively. Under parallel conditions, KCN biphasically elevated the level of cytosolic free calcium ([CA(2+)](i)) in glucose-free DMEM, peaking at 95 +/- 18 nM at 1,107 +/- 151 s, followed by a new plateau level at 249 +/- 24 nM sustained from 4,243 +/- 466 to 5,263 +/- 440 s. Cell toxicity, as measured by LDH release, was increased significantly by KCN in glucose-free DMEM but was diminished in the presence of glucose, and was correlated with DA release by chemical hypoxia. The protein kinase C (PKC) inhibitor GO6976 or staurosporine inhibited KCN-induced LDH release as well as the release of NE and DA. Taken together, selective activation of DA but not NE was correlated with the LDH release by chemical hypoxia, and was diminished with GO6976 or staurosporine. These results suggest that selective activation of PKC isoforms is involved in the chemical hypoxia-induced DA release, which may lead to neuronal cell toxicity.

Fluoride ion diffusion from a glass-ionomer cement

The aims of this study were to observe the release of fluoride ions (F-) from GC-Fuji Lining-LC(R) glass-ionomer cement, to assess the diffusion process, and to measure fluoride diffusivity (D) in the set cement. Specimens of various dimensions and shapes, ranging from discs to cylindrical rods, were fabricated for both open and embedded modes of testing. In the open mode studies, specimens with different surface to volume ratios were selected and immersed in 37 degrees C distilled water. In the embedded mode studies, only one diametral surface of the rod-shaped specimens of different lengths and diameters was exposed. F- concentration was measured using a fluoride electrode. The storage solution was analysed at predetermined intervals hourly, daily, and weekly (up to 10 weeks). Immediately after each sampling, the old storage solution was discarded and replaced with new distilled water. F- release from the set cements was detectable (0.4-3.8 ppm, varied with sample geometry), even after a 10-week sampling interval. F- release was greater in ground set cements (0.37 ppm/mg powder) than in control samples of unmixed powder (0.01 ppm/mg powder) immersed for 1 h. Two mechanisms for F- release were proposed. One was short-term and involved rapid dissolution from the cement surface. The other was more gradual and resulted in the sustained diffusion of ions through the bulk cement, which can be modelled by applying a mathematical technique known as separation of variables to Fick's Second Law of Diffusion. The mean D of F- in embedded set cements of glass-ionomer was (1.4+/-0.5)x10-11 cm2/s, with higher apparent D observed in open mode samples [(7.6+/-1.4)x10-11 cm2/s].

Laser-induced acoustic emissions in experimental dental composites

A laser thermoacoustic technique was innovated to evaluate laser-induced acoustic emissions (AEs) in experimental dental composites aged with 75% ethanol solution. Experimental composite systems of 75/25 BisGMA/TEGDMA resin filled with 0, 12.6, 30.0, and 56.5 vol% of 8-microm silanized and unsilanized BaSiO6 were analyzed. The sample size was 4.65 mm (diameter) x 0.5 mm (thick). Aging effects of immersing in 75% ethanol for up to 14 h on AEs were then evaluated. A continuous-wave CO2 laser was used to heat the samples. Acoustic emissions were collected as a function of filler fraction, laser power, silanization, and immersion time. Onset of burst-pattern acoustic signals characteristic of fracturing occurred at different laser powers for different tested groups. Acoustic emissions generally increased with laser power, in which lower laser powers produced low-amplitude (45-50 dB) signals; the amplitude distribution (50-85 dB) became more extensive as laser powers increased. After immersion, the lower laser powers could produce the same phenomenon. The higher the filler fraction, the fewer AEs generated. A large percentage AE reduction due to silanization was noted as a function of filler fraction. Unsilanized specimens showed more thermal damages than did silanized ones.

Finite element analysis of thermo-debonding mechanism in dental composites

Finite element method (FEM) has been extensively used for evaluating interfacial status inside biomaterials. This study using FEM was designed to evaluate the thermal stress behavior of a filler-matrix interface. The results were then compared to those of a previous study obtained by a laser thermoacoustic technique (LTAT). The experimental systems (75/25 Bis-GMA/TEGDMA resin reinforced with 0, 25, 50, and 75 wt% 8-microm silanized/unsilanized BaSiO6) as used in the previous study were modeled in this study. The established finite element models were based on coefficient of thermal expansion (CTE) Mismatch Phenomenon. The mechanical properties of the silane coupling agent, such as elastic modulus and thermal expansion coefficient used in the silanized model, were assumed to have optimal heat flux transfer. A third (imaginary) material was proposed to block the transfer of thermal stress between the filler and matrix in the unsilanized model. The thermal load simulation was based on steady-state thermal analysis. The results showed that: (1) The strain energy and interfacial shearing stress calculated from FEM validate the results from the previous LTAT study. (2) Comparing the stress distribution of silanized and unsilanized FEM models, the acoustic signals in LTAT study are mainly derived from debonding of the filler-matrix interface of silanized specimens, and from the matrix area of unsilanized specimens. Based on results to date, we conclude that the finite element method may be a powerful tool for exploring thermoacoustic mechanisms of dental composites.

Anti-inflammatory and neuroprotective effects of magnolol in chemical hypoxia in rat cultured cortical cells in hypoglycemic media

Our previous studies demonstrated that magnolol protects neurons against chemical hypoxia by KCN in cortical neuron-astrocyte mixed cultures (14). In the present study, we examined whether the neuroprotective effect of magnolol involve modulating inflammatory mediators, prostaglandin E2 (PGE2) and nitric oxide (NO), induced by KCN (hypoxia) or KCN plus lipopolysaccharide (LPS). In glucose-absent (hypoglycemia) media, KCN or KCN plus LPS induced increases in lactate dehydrogenase (LDH) activity by 32% and 34%, and PGE2 production by 12% and 32%, respectively. Both LDH and PGE2 increases were suppressed by 100 microM magnolol. In addition, although KCN or LPS alone did not increase NO generation, KCN plus LPS increased NO generation. This increase was reduced by 100 microM magnolol or 10 microM L-NAME, but the LDH increase and PGE2 production were not reduced by L-NAME. These findings suggest that the protective effects of magnolol against brain damage by KCN or KCN plus LPS in hypoglycemic media may involve inhibition of PGE2 production, but inhibition of NO generation may not be important.

Blockage of amyloid beta peptide-induced cytosolic free calcium by fullerenol-1, carboxylate C60 in PC12 cells

Amyloid beta protein (Abeta) alters signal transduction systems, including increases in the cytosolic free calcium ([Ca2+]i) response which have pathophysiological significance in Alzheimer's disease (AD). The purposes of this study were to elucidate the mechanism involved in Abeta's effect on the Ca2+ signal and to evaluate the effect of fullerenol-1, a water-soluble hydroxyl and superoxide radical scavenger, on the Abeta-induced Ca2+ response. Both Abeta and bradykinin (BK) dose-dependently elevated [Ca2+]i in PC12 cells. Fullerenol-1, at a concentration range between 100 nM and 1 microM, dose-dependently reduced the Abeta-induced [Ca2+]i response, but did not alter the subsequent BK-mediated process. Thapsigargin, an inhibitor of Ca2+-ATPase, released Ca2+ from the internal store and diminished the BK-mediated calcium spike but did not affect the Abeta-induced Ca2+ response. In the absence of extracellular calcium, the Abeta-induced, but not BK-induced, calcium spike was completely abolished. The Ca induced by Abeta did not enter through the voltage-dependent calcium channels or ligand gated calcium channels, because the peak of Abeta-evoked Ca2+ was not significantly altered by various Ca2+ channel blockers or a NMDA receptor antagonist MK801. In addition, neither cholera toxin nor pertussis toxin altered the Abeta-induced Ca response. The results demonstrated that Abeta-stimulated [Ca2+]i increase is due to Ca influx from an extracellular source rather than from the intracellular store. Alteration of the membrane lipid structure and permeability by free radicals generated by Abeta may be a major cause of Ca -influx. Furthermore, fullerenol-1, a novel antioxidant, may provide therapeutic benefits in neurodegenerative diseases such as AD.

Finite element analysis of brain contusion: an indirect impact study

The mechanism of brain contusion has been investigated using a series of three-dimensional (3D) finite element analyses. A head injury model was used to simulate forward and backward rotation around the upper cervical vertebra. Intracranial pressure and shear stress responses were calculated and compared. The results obtained with this model support the predictions of cavitation theory that a pressure gradient develops in the brain during indirect impact. Contrecoup pressure-time histories in the parasagittal plane demonstrated that an indirect impact induced a smaller intracranial pressure (-53.7 kPa for backward rotation, and -65.5 kPa for forward rotation) than that caused by a direct impact. In addition, negative pressures induced by indirect impact to the head were not high enough to form cavitation bubbles, which can damage the brain tissue. Simulations predicted that a decrease in skull deformation had a large effect in reducing the intracranial pressure. However, the areas of high shear stress concentration were consistent with those of clinical observations. The findings of this study suggest that shear strain theory appears to better account for the clinical findings in head injury when the head is subjected to an indirect impact.

In vivo and in vitro natural frequency analysis of periodontal conditions: an innovative method

BACKGROUND

When measuring periodontal disease, various types of equipment for making objective measurements of tooth mobility have been proposed. However, these devices and methodology are insufficient in terms of reliability. An innovative method using vibrational theories to assess the periodontal attachment level of natural teeth is presented in this study.

METHODS

Modal testing technique, a non-destructive and time-saving method, was used for non-invasive and quantitative measurement of the natural frequencies of the upper central incisor in vivo and in vitro. A finite element model was established, and modal testing experiments were simulated to assess the relationship between bone level and teeth.

RESULTS

The first dominant natural frequency of healthy human upper central incisors ranges from 710 Hz to 3,360 Hz, with an average of 1,701+/-679 Hz. Both in vitro experiment and finite element simulation showed that lowering of the attachment level causes a significant decrease in the natural frequencies, and a strong relationship (r = -0.99, P <0.01) was observed between the frequency and the bone level height.

CONCLUSIONS

Our results suggested that natural frequency is an important parameter for assessing the periodontal condition and that the modal testing technique is a useful supplemental method for assessing the attachment conditions of the periodontium.

Antioxidants prevent amyloid peptide-induced apoptosis and alteration of calcium homeostasis in cultured cortical neurons

Beta-amyloid ((A)beta) is a peptide of 39-42 amino acids that is the primary component of plaques in Alzheimer's disease (AD). The mechanism by which (A)beta expresses its neurotoxic effects may involve induction of reactive oxygen species (ROS) and elevation of intracellular free calcium levels. Cultured cortical cells were utilized to study the alterations in calcium homeostasis underlying the neurotoxic effect of (A)beta. Serum supplement B27 and vitamin E were effective in preventing neuronal death as assessed by lactate dehydrogenase (LDH) release, (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and number of apoptotic nuclei. In addition, (A)beta-induced cytosolic free calcium ([Ca2+]i) was blocked by antioxidants vitamin E and U83836E, but not by N-methyl-D-aspartic acid (NMDA) receptor antagonist MK-801, or by voltage-gated calcium channel blocker nimodipine. Taken together, the results suggest that NMDA receptor and voltage-gated calcium channels are not involved in (A)beta-induced [Ca2+]i increase. This increase appeared to be the result of extracellular calcium influx by some unknown mechanisms. In addition, antioxidants such as B27 were effective in protecting cultured cortical neurons against (A)beta, and correlated with (A)beta attenuation of early calcium response.

Microcalorimetric studies of interactions between proteins and hydrophobic ligands in hydrophobic interaction chromatography: effects of ligand chain length, density and the amount of bound protein

Using isothermal titration calorimetry (ITC), this investigation directly measured the adsorption enthalpies of proteins on various hydrophobic adsorbents. Various amounts of butyl and octyl groups were attached onto CM-Sepharose to form C4 and C8, two types of hydrophobic adsorbents. The adsorption enthalpies of both trypsinogen and alpha-chymotrypsinogen A were measured at 4.0 M NaCl and pH 10.0, in which most ionic interaction was suppressed. The adsorption isotherms of both proteins on various adsorbents were also measured, thus allowing us to calculate the Gibbs free energy and entropy of adsorption. Experimental results indicated that the adsorption of both proteins on butyl-containing adsorbents was exothermic, while their adsorption on octyl ones was endothermic. In addition, binding of both proteins with the butyl ligand is basically an adsorption process, while binding with the octyl ligand is adsorption and partition processes. Moreover, on both butyl or octyl, the adsorption enthalpy became increasingly positive as the ligand density increased, while the adsorption entropy became more positive as the alkyl chain length or density of the adsorbent increased. In addition, ITC was used to measure protein-protein interaction. The adsorption enthalpy of both proteins increased as the amount of bound protein increased, and the enthalpy increase of trypsinogen appeared to be higher than that of alpha-chymotrypsinogen A. This observation implies that protein-protein repulsion was stronger among trypsinogen molecules in the experiments.