Proteomic profiling of hepatitis B virus-related hepatocellular carcinoma with magnetic bead-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Proteomic techniques are promising strategies in the surveillance of hepatocellular carcinoma (HCC). This study aimed to investigate the serum profiling with magnetic bead (MB) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) and to further identify the biomarkers for HCC. Serum samples from 80 chronic hepatitis B (CHB) patients, 94 HCC concomitant with HBV patients and 24 healthy subjects were examined by MALDI-TOF MS after peptide enrichment on MBs. Based on the genetic algorithm, diagnostic models for HCC were established between 30 HCC patients and 24 healthy subjects/30 CHB patients. Validations were done with the remaining cases. Markers in the models were identified through liquid chromatography (LC)/MS-MS. The three groups were well separated from each other and two discrimination models were established for HCC. The overall recognition capability of these two models was 96.25% and 93.33%, respectively. Validations showed the misdiagnosis ratio for HCC was 1.6% and 23.4%, respectively. The identified biomarkers for HCC included prothrombin precursor (fragment), calcium-dependent secretion activator 1, Baculoviral inhibitor of apoptosis  repeat-containing protein 6, etc. MB-based MALDI-TOF MS is applicable in identifying the serum biomarkers and can be used in the surveillance of HCC among HBV-infected patients.

Does kV-MV dual-energy computed tomography have an advantage in determining proton stopping power ratios in patients?

Conventional kilovoltage (kV) x-ray-based dual-energy CT (DECT) imaging using two different x-ray energy spectra is sensitive to image noise and beam hardening effects. The purpose of this study was to evaluate the theoretical advantage of the DECT method for determining proton stopping power ratios (SPRs) using a combination of kV and megavoltage (MV) x-ray energies. We investigated three representative x-ray energy pairs: 100 and 140 kVp comprised the kV-kV pair, 100 kVp and 1 MV comprised the kV-MV pair, and two 1 MV x-ray beams-one with and one without external filtration-comprised the MV-MV pair. The SPRs of 34 human tissues were determined using the DECT method with these three x-ray energy pairs. Small perturbations were introduced into the CT numbers and x-ray spectra used for the DECT calculation to simulate the effects of random noise and beam hardening. An error propagation analysis was performed on the DECT calculation algorithm to investigate the propagation of CT number uncertainty to final SPR estimation and to suggest the best x-ray energy combination. We found that the DECT method using each of the three beam pairs achieved similar accuracy in determining the SPRs of human tissues in ideal conditions. However, when CT number uncertainties and artifacts such as imaging noise and beam hardening effects were considered, the kV-MV DECT improved the accuracy of SPR estimation substantially over the kV-kV or MV-MV DECT methods. Furthermore, our error propagation analysis showed that the combination of 100 kVp and 1 MV beams was close to the optimal selection when using the DECT method to determine SPRs. Overall, the kV-MV combination makes the DECT method more robust in resolving the effective atomic numbers for biological tissues than the traditional kV-kV DECT method.

Novel fiber Bragg grating fabrication system for long gratings with independent apodization and with local phase and wavelength control

We proposed and demonstrated a novel practical fiber Bragg grating (FBG) fabrication setup constructed with high performance linear stages, piezoelectric translation (PZT) stages, and a highly stable continuous wave laser. The FBG fabrication system enables writing of long FBGs by a continuous translate-and-write process and allows implementation of arbitrary chirp and apodization. A key innovation is that the local Bragg wavelength is controlled by a simple movement of the phase mask by a PZT in the direction perpendicular to its surface. The focus position of the two writing beams is not changed during the Bragg wavelength change, an intrinsic feature of the design, ensuring simplicity, robustness and stability. Apodization can be achieved by vibrating the phase mask in the direction parallel to its surface by a PZT. Phase steps can also be inserted in FBGs at any desired locations by stepping the same PZT. A long uniform FBG and a linearly chirped FBG are written to demonstrate the performance of the setup.

Increasing prevalence of gestational diabetes mellitus in Chinese women from 1999 to 2008

AIMS

To investigate the trend in the prevalence of gestational diabetes mellitus during 1999-2008 in women living in urban Tianjin, China.

METHODS

A universal screening for gestational diabetes mellitus has become an integral part of the antenatal care in Tianjin, China from 1998. A total of 105,473 pregnant women living in the six urban districts of Tianjin, China, participated in the gestational diabetes mellitus screening programme between December 1998 and December 2008. The screening test consisted of a 50-g 1-h glucose test. Women who had a glucose reading ≥7.8 mmol/l at the initial screening were invited to undergo the standard 2-h oral glucose tolerance test with a 75-g glucose load. Gestational diabetes mellitus was confirmed using the World Health Organization's diagnostic criteria.

RESULTS

The adjusted prevalence of gestational diabetes mellitus increased by 2.8 times during 1999-2008, from 2.4 to 6.8% (P<0.0001 for linear trend). In 2008, the age-specific prevalence of gestational diabetes mellitus was the highest among women aged 30-34 years (11.3%) and lowest among women aged 25 and under (1.2%). In women aged 35 years and more, the prevalence was 5.3%.

CONCLUSIONS

The prevalence of gestational diabetes mellitus has markedly been increasing in a universally screened urban Chinese female population and has become an important public health problem in China.