[Study of vital inflamed pulp therapy in immature permanent teeth with irreversible pulpitis and apical periodontitis]

To assess the treatment effectiveness of vital inflamed pulp therapy (VIPT) in immature permanent teeth with irreversible pulpitis and apical periodontitis. The faculty members in the Department of Pediatric Dentistry, the Ninth People's Hospital were invited to submit consecutive VIPT cases from June 2015 to June 2016 (follow-up periods>12 months). The cases were retrospectively reviewed, clinical symptoms and radiographic changes in periapical radiolucency were evaluated, meanwhile, the data of radiographic changes such as apical diameter and root length were calculated and analyzed with ANOVA. Totally thirteen submitted patients/cases were included (6 males and 7 females) in the present study,. The average age of patients was (9.9±1.4) years old. The average follow-up time was (26.5±6.8) months (17-37 months). At the 12-month visit, all 13 treated teeth survived, 9 out of 11 teeth with apical periodontitis showed normal radiographic manifestation. At the 3, 6 and 12 months visits, the within-case percentage changes in apical diameter were (8.0±5.1)%, (24.1±9.1)% and (70.3±10.7)%, respectively, while the within-case percentage changes in root length were (11.4±9.8)%, (14.5±9.8)% and (27.4±14.2)%, respectively. There were statistically significant differences in the changes of apical diameter (F=18.80, P<0.001) and root length (F=4.64, P=0.047) from the preoperative time to the postoperative follow-ups. VIPT might improve clinical outcomes, even achieve continued root development. VIPT can be an option in treating immature teeth with irreversible pulpitis and apical periodontitis.

Quantitative candidate gene association studies of metabolic traits in Han Chinese type 2 diabetes patients

Recent genome-wide association studies have identified many loci associated with type 2 diabetes mellitus (T2DM), hyperuricemia, and obesity in various ethnic populations. However, quantitative traits have been less well investigated in Han Chinese T2DM populations. We investigated the association between candidate gene single nucleotide polymorphisms (SNPs) and metabolic syndrome-related quantitative traits in Han Chinese T2DM subjects. Unrelated Han Chinese T2DM patients (1975) were recruited. Eighty-six SNPs were genotyped and tested for association with quantitative traits including lipid profiles, blood pressure, body mass index (BMI), serum uric acid (SUA), glycated hemoglobin (HbA1c), plasma glucose [fasting plasma glucose (FPG)], plasma glucose 120 min post-OGTT (P2PG; OGTT = oral glucose tolerance test), and insulin resistance-related traits. We found that CAMTA1, ABI2, VHL, KAT2B, PKHD1, ESR1, TOX, SLC30A8, SFI1, and MYH9 polymorphisms were associated with HbA1c, FPG, and/or P2PG; GCK, HHEX, TCF7L2, KCNQ1, and TBX5 polymorphisms were associated with insulin resistance-related traits; ABCG2, SLC2A9, and PKHD1 polymorphisms were associated with SUA; CAMTA1, VHL, KAT2B, PON1, NUB1, SLITRK5, SMAD3, FTO, FANCA, and PCSK2 polymorphisms were associated with blood lipid traits; CAMTA1, SPAG16, TOX, KCNQ1, ACACB, and MYH9 polymorphisms were associated with blood pressure; and UBE2E3, SPAG16, SLC2A9, CDKAL1, CDKN2A/B, TCF7L2, SMAD3, and PNPLA3 polymorphisms were associated with BMI (all P values <0.05). Some of the candidate genes were associated with metabolic and anthropometric traits in T2DM in Han Chinese. Although none of these associations reached genome-wide significance (P < 5 x 10(-8)), genes and loci identified in this study are worthy of further replication and investigation.

Han Chinese patients with dopa-responsive dystonia exhibit a low frequency of exonic deletion in the GCH1 gene

We identified three novel mutations of the GTP cyclohydrolase 1 (GCH1) gene in patients with familial dopa-responsive dystonia (DRD), but were unable to identify meaningful sporadic mutations in patients with no obvious family DRD background. To investigate whether GCH1 regional deletions account for the etiology of DRD, we screened for heterozygous exonic deletions in DRD families and in patients with sporadic DRD. Multiple ligation-dependent probe amplification analysis and quantitative real-time polymerase chain reaction amplification was performed in all members of our DRD cohort and in controls to detect exonic deletions in GCH1, tyrosine hydroxylase, and the epsilon-sarcoglycan-encoding (SGCE) genes. Using these techniques, we detected a GCH1 exon 1 heterozygous deletion in 1 of 10 patients with sporadic DRD. Therefore, we concluded that exonic deletion in the GCH1 gene only accounted for the etiology in a small percentage of patients with sporadic DRD in our Han Chinese cohort.

MYH9 gene polymorphisms may be associated with cerebrovascular blood flow in patients with type 2 diabetes

Genetic factors play an important role in type 2 diabetes (T2D) complications. Alteration of cerebrovascular blood flow (CBF) is a direct result of cerebrovascular diseases. However, few studies have reported the role of genetics on CBF in patients with T2D. We investigated whether single-nucleotide polymorphisms (SNPs) in metabolic disease genes are associated with CBF in patients with T2D. CBF velocities of CBF were measured in 337 Han Chinese patients with T2D using transcranial Doppler sonography, with 54 cerebrovascular blood flow parameters documented. Fifty-two SNPs from 31 metabolic disease candidate genes were genotyped in patients. Quantitative allelic association and haplotype analyses were performed for candidate gene SNPs and CBF phenotypes. Spearman correlation was used to determine the relationship between CBF parameters and basic clinical characteristics, particularly, body mass index, lipids, fibrinogen, and GHbA1c. MYH9 gene SNPs (rs875726 and rs735853) may be associated with the peak velocity of the right-middle cerebral artery. SNPs rs875726, rs2009930, and rs375246 of the MYH9 gene may be associated with the mean velocity of the right-anterior and posterior cerebral artery. The haplotype G-C-A (rs2239782-rs3752462- rs2269532) of MYH9 may be associated with CBF. MYH9 gene polymorphisms may be associated with multiple CBF phenotypes in Chinese patients with T2D. However, whether MYH9 is a candidate gene for cerebrovascular diseases in Chinese patients with T2D remains unknown.

Controllable Synthesis of Magnesium Oxysulfate Nanowires with Different Morphologies

One-dimensional magnesium oxysulfate 5Mg(OH)₂ · MgSO₄ · 3H₂O (abbreviated as 513MOS) with high aspect ratio has attracted much attention because of its distinctive properties from those of the conventional bulk materials. 513MOS nanowires with different morphologies were formed by varying the mixing ways of MgSO₄ · 7H₂O and NH₄OH solutions at room temperature followed by hydrothermal treatment of the slurries at 150 °C for 12 h with or without EDTA. 513MOS nanowires with a length of 20–60 μm and a diameter of 60–300 nm were prepared in the case of double injection (adding MgSO₄ · 7H₂O and NH₄OH solutions simultaneously into water), compared with the 513MOS with a length of 20–30 μm and a diameter of 0.3–1.7 μm in the case of the single injection (adding MgSO₄ · 7H₂O solution into NH₄OH solution). The presence of minor amount of EDTA in the single injection method led to the formation of 513MOS nanowires with a length of 100–200 μm, a diameter of 80–200 nm, and an aspect ratio of up to 1000. The analysis of the experimental results indicated that the hydrothermal solutions with a lower supersaturation were favorable for the preferential growth of 513MOS nanowires along b axis.

Blood flow estimation with harmonic Flash Echo Imaging

Blood volume flow estimation remains an important task for the functional evaluation of internal organs. In vitro and in vivo flow estimation has been carried out using Flash Echo Imaging in harmonic mode after the administration of microbubble-based ultrasound contrast agents. The in vitro flow volume rate correlated with the constant replenishment level but less so with the video intensity decay rate. The in vivo volume flow rates obtained in four dogs agreed well with CVI-Q (time domain correlation) based flow measurement. Our experimental results indicate that the volume flow rate can be accurately estimated in vitro and in vivo using harmonic Flash Echo imaging.

Destruction of contrast microbubbles and the association with inertial cavitation

The destruction of insonified Sonazoid microbubbles and its association with inertial cavitation in vitro utilizing an active acoustic detector was investigated. The experimental observation indicated that contrast microbubbles could be damaged at moderate acoustic pressures of 0.6-1.6 MPa (0.4-1.0 in mechanical index, MI). A damaged bubble could be dissolved into the medium on the order of 1 ms, implying that the destruction at moderate pressures is a relatively slow (relative to inertial bubble collapse), nonviolent dissolution process following the disruption of encapsulating surface materials. Inertial cavitation events in the presence of contrast microbubbles were observed using multiple highly intense ultrasound (US) pulses (>1.6 MPa). This observation suggested that intense US might disintegrate contrast microbubbles, and fragments of disintegrated microbubbles could be activated by an upcoming highly intense imaging pulse. The above results imply that inertial cavitation is unlikely to take place in the presence of Sonazoid contrast microbubbles when exposed to diagnostic US with an MI <1.

Subharmonic imaging of contrast agents

Ultrasound contrast agents promise to improve the sensitivity and specificity of diagnostic ultrasound imaging. It is of great importance to adapt ultrasound equipment for optimal use with contrast agents e.g., by exploiting the nonlinear properties of the contrast microbubbles. Harmonic imaging is one technique that has been extensively studied and is commercially available. However, harmonic imaging is associated with problems, due to second harmonic generation and accumulation within the tissue itself. Given the lack of subharmonic generation in tissue, one alternative is the creation of subharmonic images by transmitting at the fundamental frequency (fo) and receiving at the subharmonic (fo/2). Subharmonic imaging should have a much better lateral resolution and may be suitable for scanning deep-lying structures owing to the higher transmit frequency and the much smaller attenuation of scattered subharmonic signals. In this paper, we will review different aspects of subharmonic imaging including implementation, in-vitro gray-scale imaging and subharmonic aided pressure estimation.

Ultrasonic characterization of the nonlinear properties of contrast microbubbles

The nonlinear properties of microbubble contrast agents have been used to create contrast-specific imaging modalities such as harmonic imaging and subharmonic imaging. Thus, a better understanding of the nonlinear performance of contrast microbubbles may enhance the diagnostic capabilities of medical ultrasound (US) imaging. The first and second harmonic, the 1/2 order subharmonic and the 3/2 order ultraharmonic components in spectra of scattered signals from Optison microbubbles insonified at 2 and 4 MHz have been investigated using an in vitro laboratory pulse-echo system. The development of these signal components over time is quite different for 2-MHz insonification compared to 4-MHz insonification. Scattered subharmonic and ultraharmonic signals are much more time-dependent than first and second harmonic echoes. The dependence of the first and second harmonic, subharmonic and ultraharmonic components on acoustic pressure for 2-MHz insonification is similar to that for 4-MHz insonification. The first and second harmonic components increase linearly with acoustic pressure (in double logarithmic scales) and the subharmonic and ultraharmonic amplitudes undergo rapid growths in the intermediate acoustic pressure range and much slower increases at both lower and higher acoustic pressures.

Effect of filling gases on the backscatter from contrast microbubbles: theory and in vivo measurements

Two surfactant-based contrast agents, ST44 and ST68, were produced according to US Patent # 5,352,436 and filled with either air, C4F10 (perfluorobutane) or SF6 (sulfur hexaflouride). Ten rabbits received i.v. injections of each agent/gas combination with 5 repetitions of each dose (range: 0.005-0.13 mL/kg). A custom-made 10-MHz cuff transducer was placed around the surgically exposed distal aorta and audio Doppler signals were acquired in vivo. Quantitative in vivo dose responses were calculated off-line using spectral power analysis and compared to a theoretical model of microbubble dissolution and enhancement. For qualitative comparisons, 10 rabbits were imaged pre- and postcontrast administration (dose: 0.1 mL/kg) in gray-scale and colour. All agent/gas combinations produced marked Doppler enhancement with air bubbles enhancing least of all (p < 0.0001) and ST68-SF6 best of all (maximum: 27.6 +/- 2.04 dB; p < 0.012). There were no significant differences between other agent/gas combinations (0.30 < p < 0.70). Theoretical enhancement was within 1 order of magnitude of the experimental observations (i.e., deviations of up to 10 dB). The duration of contrast enhancement was 1-2 min for air-filled bubbles, 3-5 min for SF6-filled bubbles and more than 7 min for C4F10-filled bubbles. In conclusion, ST68-SF6 microbubbles produced most in vivo enhancement of the agent/gas combinations studied. Theory matched the measurements within an order of magnitude.

Subharmonic imaging with microbubble contrast agents: initial results

The subharmonic emission from insonified contrast microbubbles was used to create a new imaging modality called Subharmonic Imaging. The subharmonic response of contrast microbubbles to ultrasound pulses was first investigated for determining adequate acoustic transmit parameters. Subharmonic A-lines and gray scale images were then obtained using a laboratory pulse-echo system in vitro and a modified ultrasound scanner in vivo. Excellent suppression of all backscattered signals other than from contrast microbubbles was achieved for subharmonic A-lines in vitro while further optimization is required for in vivo gray scale subharmonic images.

Pressure dependence of subharmonic signals from contrast microbubbles

Noninvasive pressure estimation in heart cavities and in major vessels would provide clinicians with a valuable tool for assessing patients with heart and vascular diseases. Some microbubble-based ultrasound contrast agents are particularly well suited for pressure measurements because their substantial compressibility enables microbubbles to vary significantly in size in response to changes in pressure. Pressure changes should then affect reflectivity of microbubbles after intravenous injection of a contrast agent. This has been demonstrated with a galactose-based contrast agent using 2.0-MHz ultrasound tone bursts. Preliminary results indicate that, over the pressure range of 0-186 mmHg, the subharmonic amplitude of scattered signals decreases by as much as 10 dB under optimal acoustic settings and the first and second harmonic amplitudes decrease by less than 3 dB. An excellent correlation between the subharmonic amplitude and the hydrostatic pressure suggests that the subharmonic signal may be utilized for noninvasive detection of pressure changes.

Tissue-specific US contrast agent for evaluation of hepatic and splenic parenchyma

PURPOSE

To evaluate the recently developed ultrasonographic (US) contrast agent SHU 563A, which is specifically taken up by the reticuloendothelial system (RES).

MATERIALS AND METHODS

Color Doppler imaging (CDI) was performed in a gel phantom, with SHU 563A microbubbles in stationary suspension. CDI was performed in vivo in five woodchucks with natural hepatomas and in 12 rabbits before and after intravenous bolus injections of SHU 563A (0.16-0.48 mL/kg). After a 15-135-minute delay, the liver and spleen were scanned again, and the image findings were compared with pathologic analysis results.

RESULTS

Phantom CDI demonstrated a random mosaic color pattern in spite of the lack of flow. This phenomenon, which is associated with bubble rupture, is termed induced acoustic emission. In vivo, delayed imaging demonstrated acoustic emission signals in normal parenchyma, whereas no mosaic color was seen in regions lacking reticuloendothelial cells (e.g., tumors). Four of 12 VX-2 tumors detected with pathologic analysis were detected with US alone; the remaining eight tumors were detected by using US with contrast agent (100%, P = .0078). Nine of 20 hepatomas were detected at baseline US, whereas 17 were detected after administration of SHU 563A (P = .0215). Acoustic emission enabled detection of hepatic tumors as small as 3 mm in diameter.

CONCLUSION

CDI with SHU 563A demonstrates a random mosaic color pattern, even without flow. The characteristic appearance of acoustic emission signals provides a distinctive method of visualizing normal hepatic tissues and substantially improves the detectability of hepatic tumors.