Amide Proton Transfer Imaging Allows Detection of Glioma Grades and Tumor Proliferation: Comparison with Ki-67 Expression and Proton MR Spectroscopy Imaging

BACKGROUND AND PURPOSE

Prognosis in glioma depends strongly on tumor grade and proliferation. In this prospective study of patients with untreated primary cerebral gliomas, we investigated whether amide proton transfer-weighted imaging could reveal tumor proliferation and reliably distinguish low-grade from high-grade gliomas compared with Ki-67 expression and proton MR spectroscopy imaging.

MATERIALS AND METHODS

This study included 42 patients with low-grade (n = 28) or high-grade (n = 14) glioma, all of whom underwent conventional MR imaging, proton MR spectroscopy imaging, and amide proton transfer-weighted imaging on the same 3T scanner within 2 weeks before surgery. We assessed metabolites of choline and N-acetylaspartate from proton MR spectroscopy imaging and the asymmetric magnetization transfer ratio at 3.5 ppm from amide proton transfer-weighted imaging and compared them with histopathologic grade and immunohistochemical expression of the proliferation marker Ki-67 in the resected specimens.

RESULTS

The asymmetric magnetization transfer ratio at 3.5 ppm values measured by different readers showed good concordance and were significantly higher in high-grade gliomas than in low-grade gliomas (3.61% ± 0.155 versus 2.64% ± 0.185, P = .0016), with sensitivity and specificity values of 92.9% and 71.4%, respectively, at a cutoff value of 2.93%. The asymmetric magnetization transfer ratio at 3.5 ppm values correlated with tumor grade (r = 0.506, P = .0006) and Ki-67 labeling index (r = 0.502, P = .002). For all patients, the asymmetric magnetization transfer ratio at 3.5 ppm correlated positively with choline (r = 0.43, P = .009) and choline/N-acetylaspartate ratio (r = 0.42, P = .01) and negatively with N-acetylaspartate (r = -0.455, P = .005). These correlations held for patients with low-grade gliomas versus those with high-grade gliomas, but the correlation coefficients were higher in high-grade gliomas (choline: r = 0.547, P = .053; N-acetylaspartate: r = -0.644, P = .017; choline/N-acetylaspartate: r = 0.583, P = .036).

CONCLUSIONS

The asymmetric magnetization transfer ratio at 3.5 ppm may serve as a potential biomarker not only for assessing proliferation, but also for predicting histopathologic grades in gliomas.

Construction of crystal structure prototype database: methods and applications

Crystal structure prototype data have become a useful source of information for materials discovery in the fields of crystallography, chemistry, physics, and materials science. This work reports the development of a robust and efficient method for assessing the similarity of structures on the basis of their interatomic distances. Using this method, we proposed a simple and unambiguous definition of crystal structure prototype based on hierarchical clustering theory, and constructed the crystal structure prototype database (CSPD) by filtering the known crystallographic structures in a database. With similar method, a program structure prototype analysis package (SPAP) was developed to remove similar structures in CALYPSO prediction results and extract predicted low energy structures for a separate theoretical structure database. A series of statistics describing the distribution of crystal structure prototypes in the CSPD was compiled to provide an important insight for structure prediction and high-throughput calculations. Illustrative examples of the application of the proposed database are given, including the generation of initial structures for structure prediction and determination of the prototype structure in databases. These examples demonstrate the CSPD to be a generally applicable and useful tool for materials discovery.

[Analysis of Koch phenomenon of Mycobacterium tuberculosis-infected guinea pigs vaccinated with recombinant tuberculosis vaccine AEC/BC02]

OBJECTIVE

To observe the Koch phenomenon of Mycobacterium tuberculosis(MTB)-infected guinea pigs after vaccinated with killed H37Ra bacteria or tuberculosis vaccine candidate AEC/BC02.

METHODS

Eighteen guinea pigs were challenged subcutaneously with 5.0×10(3) CFU MTB and after 40 days were divided into 3 groups (6 per group): NS group, AEC/BC02 group and H37Ra group, which were injected intramuscularly 3 times at 1 day interval with normal saline, AEC/BC02 vaccine and killed H37Ra bacteria respectively. Three weeks after the first vaccination, all guinea pigs were sacrificed to evaluate gross pathological scores for liver, spleen and lung, bacterial loads in lung and spleen, and lung inflammation.

RESULTS

The gross pathological score in H37Ra group (48±26) was lower than that in NS group(62±15), but the difference was not significant (t=1.093, P=0.300). The AEC/BC02 group had a significantly lower gross pathological score (36±15) than NS group (t=2.980, P=0.014). No significant difference between H37Ra group and AEC/BC02 group was observed (t=1.009, P=0.337). The spleen bacterial load [(5.31±0.80) log10 CFU]in H37Ra group was slightly lower than that in NS group[(5.57±0.75) log10 CFU] but the difference was not significant (t=1.581, P=0.574). In AEC/BC02 group bacterial load in the spleen was (4.64±0.64) log10 CFU and significantly lower than NS group (t=2.306, P=0.044) and no significant difference between H37Ra group and AEC/BC02 group was observed (t=1.602, P=0.140). Meanwhile, the lung bacterial load in AEC/BC02 group was (3.71±1.01) log10 CFU and in H37Ra group was (3.82±1.25) log10 CFU. Compared to (4.15±0.69) log10 CFU in the NS group, no significant differences were found (t=0.881, P=0.399; t=0.566, P=0.584, respectively). For the lung inflammation, the inflamed areas in H37Ra group were significantly larger [(33.0±4.4%)] than those in both NS group [(14.8±8.4) %, t=4.719, P=0.001] and AEC/BC02 group [(14.8±8.4) %, t=3.616, P=0.005], and no significant differences were seen between AEC/BC02 group and NS group (t=1.041, P=0.322).

CONCLUSION

The lung inflammation indicated that killed H37Ra bacteria evoked an obvious Koch reaction in the MTB-infected guinea pigs, whereas AEC/BC02 vaccine showed a low risk of causing Koch phenomenon.

Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide

In the present study, the leaching of metals from large pieces of computer printed circuit boards (CPCBs) was studied. A combination of citric acid (0.5 M) and 1.76 M hydrogen peroxide (H₂O₂) was used to leach the metals from CPCB piece. The influence of system variables such as H₂O₂ concentration, concentration of citric acid, shaking speed, and temperature on the metal leaching process was investigated. The complete metal leaching was achieved in 4 h from a 4 × 4 cm CPCB piece. The presence of citric acid and H₂O₂ together in the leaching solution is essential for complete metal leaching. The optimum addition amount of H₂O₂ was 5.83 %. The citric acid concentration and shaking speed had an insignificant effect on the leaching of metals. The increase in the temperature above 30 °C showed a drastic effect on metal leaching process.

Release and toxicity comparison between industrial- and sunscreen-derived nano-ZnO particles

Many consumer products containing ZnO have raised concern for safety in regard to environmental impact and the public health. Widely used sunscreens for protecting against UV and avoiding sunburns represent a great exposure to nano-ZnO, one of the ingredients commonly applied in sunscreens. Applying nanoproducts on beaches may release nanoparticles unintentionally into the ocean. Despite the accumulation of such nanoproducts in the ocean harming or being detrimental to critical marine organisms, few studies have investigated the release and potential toxicity of nanoparticles extracted from products and compared them with those from industrial-type nanoparticles. Results show that the cytotoxicity of both industrial- and sunscreen-derived nano-ZnO to the marine diatom algae, Thalassiosira pseudonana, increased as exposure increases over time, as measured by growth inhibition (%) of the algae at a constant concentration of nano-ZnO (10 mg/L). The extent of toxicity appeared to be higher from industrial-type nano-ZnO compared with sunscreen-extracted nano-ZnO, though the extent becomes similar when concentrations increase to 50 mg/L. On the other hand, at a fixed exposure time of 48 h, the cytotoxicity increases as concentrations increase with the higher toxicity shown from the industrial-type compared with sunscreen-induced nano-ZnO. Results indicate that while industrial-type nano-ZnO shows higher toxicity than sunscreen-derived nano-ZnO, the release and extent of toxicity from nano-ZnO extracted from sunscreen are not trivial and should be monitored for the development of safe manufacturing of nanomaterials-induced products.

Genome-wide analysis of chitinase genes and their varied functions in larval moult, pupation and eclosion in the rice striped stem borer, Chilo suppressalis

Some insect chitinases are required to degrade chitin and ensure successful metamorphosis. Although chitinase genes have been well characterized in several model insects, no reports exist for the rice striped stem borer, Chilo suppressalis, a highly destructive pest that causes huge yield losses in rice production. Here, we conducted a genome-level analysis of chitinase genes in C. suppressalis. After amplification of full-length transcripts with rapid amplification of cDNA ends, we identified 12 chitinase genes in C. suppressalis. All these genes had the conserved domains and motifs of glycoside hydrolase family 18 and grouped phylogenetically into five subgroups. C. suppressalis chitinase 1 (CsCht1) was highly expressed in late pupae, whereas CsCht3 was abundant in early pupae. Both CsCht2 and CsCht4 were highly expressed in larvae. CsCht2 was abundant specifically in the third-instar larvae and CsCht4 showed periodic high expression in 2- to 5-day-old larvae in each instar. Tissue specific expression analysis indicated that CsCht1 and CsCht3 were highly expressed in epidermis whereas CsCht2 and CsCht4 were specifically abundant in the midgut. Knockdown of CsCht1 resulted in adults with curled wings, indicating that CsCht1 might have an important role in wing expansion. Silencing of CsCht2 or CsCht4 arrested moulting, suggesting essential roles in larval development. When the expression of CsCht3 was interfered, defects in pupation occurred. Overall, we provide here the first catalogue of chitinase genes in the rice striped stem borer and have elucidated the functions of four chitinases in metamorphosis.

A weighted scoring system to differentiate malignant liposarcomas from benign lipomas

PURPOSE

To construct a scoring system to differentiate malignant liposarcomas from benign lipomas by comparing their clinical and magnetic resonance imaging (MRI) features.

METHODS

Clinical and MRI features of 33 women and 33 men aged 17 to 83 (mean, 53) years who underwent resection of malignant liposarcomas (n=32) or benign lipomas (n=34) were reviewed.

RESULTS

The 5 strongest predictors of liposarcoma were male gender, larger tumour maximum dimension, deep to fascia, thick non-fatty septum or nodule, and internal cystic change. A weighted scoring system was constructed using the 5 strongest predictors as: Z score=10X1+X2+12X3+15X4+10X5, respectively. A cut-off score of 35 was used; all 32 malignant liposarcomas and 4 of 34 benign lipomas scored >35. The cut-off score of ≤35 could predict 30 of 66 lipomatous tumours as benign with a negative predictive value of 100% (p<0.0001).

CONCLUSION

The 5 strongest clinical and MRI features were identified to construct a scoring system to differentiate malignant from benign lipomatous tumours. Further validation in independent populations is required.

Heme oxygenase 1 induction protects myocardiac cells against hypoxia/reoxygenation-induced apoptosis : The role of JNK/c-Jun/Caspase-3 inhibition and Akt signaling enhancement

BACKGROUND

Although recent studies have found that heme oxygenase (HO)-1 plays an important role in myocardiac cell survival, the precise mechanisms occurring during hypoxia/reoxygenation (H/R) injury remain unclear. Therefore, the aim of this study was to investigate the cytoprotective mechanisms of HO-1 against H/R-induced myocardiac cell apoptosis and to explore whether the Akt signaling pathway contributed to the protection provided by HO-1.

METHODS

Cobalt protoporphyrin (CoPP, a pharmacologic inducer of HO-1) was employed to induce the over-expression of HO-1 before H/R in H9c2 cells. Hoechst staining and flow cytometry were used to examine the extent of apoptosis. Furthermore, the effect of HO-1 on Akt, JNK, and the expression of apoptosis-related proteins (c-JUN and Caspase-3) was determined by Western blotting.

RESULTS

The results showed that over-expressed HO-1 could significantly protect myocardiac cells against H/R-induced apoptosis in H9c2 cells. Furthermore, the protein expression of p‑Akt increased and of p‑JNK decreased in the H/R injury H9c2 cells when treated with CoPP. The apoptosis-related proteins c‑Jun and caspase-3 were both inhibited by over-expression of HO-1. At the same time, retreatment with zinc protoporphyrin (ZnPP, a specific inhibitor of HO-1 enzymatic activity) or LY294002 (an inhibitor of Akt1) reversed the HO-1-induced changes.

CONCLUSION

In summary, our results suggest that HO-1 can decrease H/R-induced myocardiac cell apoptosis; the mechanism may be related to the activation of the Akt signaling pathway and, furthermore, to the inhibition of the JNK/c-Jun/caspase-3 signaling pathway.

Catenation of carbon in LaC2 predicted under high pressure

Carbon has the capability of forming various bonding states that affect the structures and properties of transition metal carbides. In this work, structural search was performed to explore the structural diversity of LaC2 at pressures of 0.0-30.0 GPa. Five stable structures of LaC2 reveal a variety of carbon structural units ranging from a dimer to bent C3, zigzag C4 and armchair polymer chains. A series of pressure-induced structural transformations are predicted, I4/mmm (i.e. experimental α phase) →C2/c→Pnma→Pmma, which involve the catenation of carbon from a dimer to zigzag C4 units and further to armchair polymer chains. The bent C3 unit appears in a novel Immm structure. This structure is the theoretical ground state of LaC2 under ambient conditions, but is kinetically inaccessible from the experimental α phase. LaC2 becomes thermodynamically metastable relative to La2C3 + diamond above 17.1 GPa, and eventually decomposes into constituent elements above 35.6 GPa. The presented results indicate that catenation of carbon can be realized even in simple inorganic compounds under nonambient conditions.

Ethnic disparities in risk of cardiovascular disease, end-stage renal disease and all-cause mortality: a prospective study among Asian people with Type 2 diabetes

AIM

To study prospectively the ethnic-specific risks of cardiovascular disease, end-stage renal disease and all-cause mortality in patients with Type 2 diabetes mellitus among native Asian subpopulations.

METHODS

A total of 2337 subjects with Type 2 diabetes (70% Chinese, 17% Malay and 13% Asian Indian) were followed for a median of 4.0 years. Time-to-event analysis was used to study the association of ethnicity with adverse outcomes.

RESULTS

Age- and gender-adjusted hazard ratios for cardiovascular disease in ethnic Malay and Asian Indian subjects were 2.01 (1.40-2.88; P<0.0001) and 1.60 (1.07-2.41; P=0.022) as compared with Chinese subjects. Adjustment for conventional cardiovascular disease risk factors, including HbA1c , blood pressure and lipid profile, slightly attenuated the hazards in Malay (1.82, 1.23-2.71; P=0.003) and Asian Indian subjects (1.47, 0.95-2.30; P=0.086); However, further adjustment for baseline renal function (estimated GFR) and albuminuria weakened the cardiovascular disease risks in Malay (1.48, 0.98-2.26; P=0.065) but strengthened that in Asian Indian subjects (1.81, 1.14-2.87; P=0.012). Competing-risk regression showed that the age- and gender-adjusted sub-distribution hazard ratio for end-stage renal disease was 1.87 (1.27-2.73; P=0.001) in Malay and 0.39 (0.18-0.83; P=0.015) in Asian Indian subjects. Notably, the difference in end-stage renal disease risk among the three ethnic groups was abolished after further adjustment for baseline estimated GFR and albuminuria. There was no significant difference in risk of all-cause mortality among the three ethnic groups.

CONCLUSIONS

Risks of cardiovascular and end-stage renal diseases in native Asian subjects with Type 2 diabetes vary substantially among different ethnic groups. Differences in prevalence of diabetic kidney disease may partially explain the ethnic disparities.

Leaching of metals from printed circuit board powder by an Aspergillus niger culture supernatant and hydrogen peroxide

Removal of chemical coating of PCB powder using 0.1 M sodium hydroxide solution.

Effects of silencing MTA1 gene by RNA interference on invasion and metastasis of endometrial carcinoma

OBJECTIVE

The study aimed at the silence effect of MAT1 gene and proteins in Ishikawa cell of human endometrial carcinoma cell line through RNAi mediated by siRNA and also discussed the effect of MTA1 gene silence on the invasion and metastasis of endometrial carcinoma.

MATERIALS AND METHODS

According to the principle of designing siRNA sequence, siRNA aiming at MTA1 gene (MTA1-siRNA) and siRNA used for negative control (Control-siRNA) were designed and synthesized and Ishikawa cell was transfected by transfection reagents. RT-PCR method as well as western blot was used, respectively, to detect the MTA1 mRNA and protein expression of stably transfected cells. Transwell method and scarification experiment were adopted to detect the invasion and metastasis of Ishikawa cells.

RESULTS

The expression results of MTA1 on the levels of mRNA and protein showed that the expression level in transfected MTA1-siRNA group was obviously lower than that in non-transfected group and transfected control-siRNA group (p <0.05), while there was no significant difference between non-transfected group and transfected control-siRNA group (p > 0.05). Effective interference on the expression of MTA1 gene remarkably lowered the invasion and metastasis of endometrial carcinoma Ishikawa cells.

CONCLUSION

RNAi aiming at MTA1 can effectively inhibit the expression of MTA1 in endometrial carcinoma Ishikawa cells and the effective silence of MTA1 can weaken the invasion and metastasis of Ishikawa cells, which provides a new strategy for gene therapy of endometrial carcinoma and an experimental basis for inhibiting the invasion and metastasis of endometrial carcinoma.