Independent and combined effects of smoking, drinking and depression on periodontal disease

BACKGROUND

Periodontitis is a complex chronic inflammatory disease that is particularly associated with health-related conditions such as smoking, excessive drinking and depression. This research aimed to investigate the interaction between these lifestyles factors on periodontitis risk.

METHODS

This study included participants who participated in the National Health and Nutrition Examination Survey in the United States between 2009 and 2014. They had completed oral health-periodontal examination, Smoking-Cigarette Use Questionnaire, Alcohol Use Questionnaire, and Patient Health Questionnaire. Periodontal clinical attachment loss (CAL) of 3 mm or more and Patient Health Questionnaire-9 (PHQ-9) of 10 scores or more were used to identify periodontitis and depression, respectively. Daily alcohol consumption in the past year was classified into three levels: low (1 drink or less), moderate (between 1 and 3 drinks), and heavy drinking (4 drinks or more), while smoking was defined as having smoked at least 100 cigarettes in one's lifetime. Then, the logistic regression combined with interaction models were used to analyze the independent and combined effects of smoking, drinking and depression on periodontitis risk.

RESULTS

The results indicated a statistically significant multiplicative interaction between smoking and depression in relation to the development of periodontitis, both in the overall population (P = 0.03) and among male participants (P = 0.03). Furthermore, among individuals experiencing depression, smoking was found to significantly increase the prevalence of periodontitis by 129% in the younger age group compared to non-smokers (odds ratio [OR]: 2.29; 95% confidence interval [CI]: 1.10 to 4.76). However, the interaction between smoking and alcohol consumption was only significant among females (P < 0.05). There was a dose-dependent relationship between drinking frequency and smoking on periodontitis prevalence. In the smoking population, occasional drinking (OR: 1.70; 95% CI: 1.22 to 2.37) and regular drinking (OR: 2.28; 95% CI: 1.68 to 3.11) significantly increased the prevalence of periodontitis compared to individuals without these two factors.

CONCLUSION

These results suggested that there were interactive effects between smoking, drinking and depression on periodontitis risk and policies aimed at healthy behaviours and mental health may be beneficial for our oral health.

The convergent xenogeneic silencer MucR predisposes α-proteobacteria to integrate AT-rich symbiosis genes

Bacterial adaptation is largely shaped by horizontal gene transfer, xenogeneic silencing mediated by lineage-specific DNA bridgers (H-NS, Lsr2, MvaT and Rok), and various anti-silencing mechanisms. No xenogeneic silencing DNA bridger is known for α-proteobacteria, from which mitochondria evolved. By investigating α-proteobacterium Sinorhizobium fredii, a facultative legume microsymbiont, here we report the conserved zinc-finger bearing MucR as a novel xenogeneic silencing DNA bridger. Self-association mediated by its N-terminal domain (NTD) is required for DNA–MucR–DNA bridging complex formation, maximizing MucR stability, transcriptional silencing, and efficient symbiosis in legume nodules. Essential roles of NTD, CTD (C-terminal DNA-binding domain), or full-length MucR in symbiosis can be replaced by non-homologous NTD, CTD, or full-length protein of H-NS from γ-proteobacterium Escherichia coli, while NTD rather than CTD of Lsr2 from Gram-positive Mycobacterium tuberculosis can replace the corresponding domain of MucR in symbiosis. Chromatin immunoprecipitation sequencing reveals similar recruitment profiles of H-NS, MucR and various functional chimeric xenogeneic silencers across the multipartite genome of S. fredii, i.e. preferring AT-rich genomic islands and symbiosis plasmid with key symbiosis genes as shared targets. Collectively, the convergently evolved DNA bridger MucR predisposed α-proteobacteria to integrate AT-rich foreign DNA including symbiosis genes, horizontal transfer of which is strongly selected in nature.

[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.

Global Transcriptional Repression of Diguanylate Cyclases by MucR1 Is Essential for Sinorhizobium-Soybean Symbiosis

The ubiquitous bacterial second messenger c-di-GMP is intensively studied in pathogens but less so in mutualistic bacteria. Here, we report a genome-wide investigation of functional diguanylate cyclases (DGCs) synthesizing c-di-GMP from two molecules of GTP in Sinorhizobium fredii CCBAU45436, a facultative microsymbiont fixing nitrogen in nodules of diverse legumes, including soybean. Among 25 proteins harboring a putative GGDEF domain catalyzing the biosynthesis of c-di-GMP, eight functional DGCs were identified by heterogenous expression in Escherichia coli in a Congo red binding assay. This screening result was further verified by in vitro enzymatic assay with purified full proteins or the GGDEF domains from representative functional and nonfunctional DGCs. In the same in vitro assay, a functional EAL domain catalyzing the degradation of c-di-GMP into pGpG was identified in a protein that has an inactive GGDEF domain but with an active phosphodiesterase (PDE) function. The identified functional DGCs generally exhibited low transcription levels in soybean nodules compared to free-living cultures, as revealed in transcriptomes. An engineered upregulation of a functional DGC in nodules led to a significant increase of c-di-GMP level and symbiotic defects, which were not observed when a functional EAL domain was upregulated at the same level. Further transcriptional analysis and gel shift assay demonstrated that these functional DGCs were all transcriptionally repressed in nodules by a global pleiotropic regulator, MucR1, that is essential in Sinorhizobium-soybean symbiosis. These findings shed novel insights onto the systematic regulation of c-di-GMP biosynthesis in mutualistic symbiosis. IMPORTANCE The ubiquitous second messenger c-di-GMP is well-known for its role in biofilm formation and host adaptation of pathogens, whereas it is less investigated in mutualistic symbioses. Here, we reveal a cocktail of eight functional diguanylate cyclases (DGCs) catalyzing the biosynthesis of c-di-GMP in a broad-host-range Sinorhizobium that can establish nitrogen-fixing nodules on soybean and many other legumes. These functional DGCs are generally transcribed at low levels in soybean nodules compared to free-living conditions. The engineered nodule-specific upregulation of DGC can elevate the c-di-GMP level and cause symbiotic defects, while the upregulation of a phosphodiesterase that quenches c-di-GMP has no detectable symbiotic defects. Moreover, eight functional DGCs located on two different replicons are all directly repressed in nodules by a global silencer, MucR1, that is essential for Sinorhizobium-soybean symbiosis. These findings represent a novel mechanism of a strategic regulation of the c-di-GMP biosynthesis arsenal in prokaryote-eukaryote interactions.

[Association between periodontitis and Alzheimer disease: a meta analysis]

PURPOSE

To evaluate the association between periodontitis and Alzheimer's disease.

METHODS

Databases of PubMed, Embase, CNKI, VIP and WanFang databases were searched for the relevant observational studies focusing on the association between periodontitis and Alzheimer's disease. The deadline was January 2019. Data quality evaluation and extraction were independently conducted by two authors. Meta analysis was performed using RevMan 5.2 software.

RESULTS

Four case-control, five cross-sectional and two cohort studies were included. One cohort study and four case-control studies treated periodontitis as the exposure factor, all five cross-sectional studies and the other cohort study treated Alzheimer's disease as the exposure factor. The results of meta analysis showed that patients with periodontitis had a higher risk of Alzheimer's disease (RR=1.22, 95%CI: 1.13-1.33, P<0.00001), and the risk was more higher in patients with severe periodontitis(RR=1.54, 95%CI:1.05-2.26, P=0.03<0.05); but there was no significant difference in the risk of Alzheimer's disease in patients with moderate periodontitis (RR=1.19, 95%CI: 0.98-1.44, P=0.07>0.05). The results of meta-analysis also showed that probing depth in patients with Alzheimer's disease was significantly higher than that of the control group (MD=2.58, 95%CI: 0.17-4.99, P=0.04<0.05), as well as clinical attachment loss (MD=1.27, 95%CI: 0.43-2.10, P=0.003<0.05), plaque index (MD=1.14, 95%CI: 0.85-1.44, P<0.00001) and the percentage of bleeding on probing (MD=21.11%, 95%CI: 18.23%-23.99%, P<0.00001). Furthermore, the number of present teeth in patients with Alzheimer's disease was significantly less than that of the control group (MD=-3.77, 95% CI: -6.89- -0.65, P=0.02<0.05).

CONCLUSIONS

The current evidence indicates that periodontitis is associated with Alzheimer's disease and patients with periodontitis (especially severe periodontitis) probably have a higher risk of developing Alzheimer's disease, and patients with Alzheimer's disease tend to have poorer periodontal health. However, the number of existing studies is limited and more clinical evidences are needed to support the correlation between these two diseases.

Assessing the magnetic resonance imaging in determining the depth of invasion of tongue cancer

OBJECTIVES

To assess the magnetic resonance imaging (MRI) in predicting tumour's depth of invasion (DOI) of tongue cancer by comparing to pathology and to determine the cut-off value of MRI-derived DOI for lymph node metastasis.

PATIENTS AND METHODS

In a retrospective analysis, 156 patients with newly diagnosed tongue cancer were included. Tumour's DOI was compared between MRI measurement and pathology by Pearson correlation coefficient and paired t test. The accuracy of MRI-derived DOI was compared to the pathological DOI. The relationship between MRI-derived DOI and cervical lymph node metastasis was calculated by receiver operating characteristic curve.

RESULTS

Tumour's DOI was well correlated between MRI measurement and pathology with correlation coefficients of 0.77. MRI-derived DOI was 3.4 mm (28%) larger than pathology. The accuracy of MRI in deciding pathological DOI was 67.9%. The cut-off value of MRI-derived DOI was 10.5 mm for lymph node metastasis of tongue cancer.

CONCLUSION

Magnetic resonance imaging can be used as a reference to determine tumour's DOI of tongue cancer. Tumour with MRI-derived DOI larger than 10.5 mm deserves simultaneous neck dissection at initial surgery.

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.

Chinese patients with gastric cancer need targeted adjuvant chemotherapy schemes

BACKGROUND

Gastric cancer (GC) is one of the most common cancers in China. Adjuvant chemotherapy (AC) is a routine auxiliary treatment for GC recommended by the guidelines issued in 2011 by the Ministry of Health of the People's Republic of China, but the relevant credible consequences in China have been insufficient because of China's late start and ethical concerns.

METHODS

A series of databases, including Cochrane Library, MEDLINE, EMBASE, the Chinese database of the National Knowledge Infrastructure and the VIP database, were searched by 2 reviewers independently for studies investigating AC for GC through March 2012. The retrieved literature was screened according to the eligibility criteria.

RESULTS

A total of 35 randomized control trials (RCTs) were subjected to the final analysis, including 4,043 patients in treatment group and 3,884 in the control group, as well as 4 clinical-control trials (CCTs), which accessed the final analysis with 238 and 252 patients, respectively. AC reduced the risk of death as a protective treatment with statistical significance (HR=0.91, 95%CI: [0.85, 0.97], P=0.002), and it seemed more effective for Asian than non-Asian patients. The effects of AC were not influenced by the starting time (P>0.05). D2 lymphadenectomy-based chemotherapy was effective (HR=0.89, 95%CI: [0.80, 0.99], P=0.04). Oral S-1 40 mg/m2 after D2 lymphadenectomy might be a better choice for Asians with advanced GC and might result in a greater reduction of adverse events than in non-Asian patients. GRADE quality assessment determined that the strength of the evidence from foreign studies from Europe, the United States and Asian countries other than China was high, while it was moderate for Chinese studies.

CONCLUSION

AC was effective or even curative in Chinese patients in general, although it is still necessary to optimize a targeted AC scheme for Chinese patients with GC.

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.