Examining the efficacy of intravenous administration of predatory bacteria in rats

The proteobacteria Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus are obligate predators of Gram-negative bacteria, and have been proposed to be used to treat multidrug-resistant bacterial infections. The ability of predatory bacteria to reduce bacterial burden in vivo within the lungs of rats has been demonstrated, but it was unknown if predatory bacteria can attenuate systemic bacterial burden administered intravenously. In this study, we first assessed the safety of intravenous inoculation of predatory bacteria in rats. No rat morbidity or adverse histopathology of various organs due to predatory bacteria administration was observed. An increase in proinflammatory cytokines (TNFα and KC/GRO) was observed at two hours post-inoculation; however, cytokines returned to baseline levels by 18 hours. Furthermore, bacterial dissemination analysis demonstrated that predatory bacteria were efficiently cleared from the host by 20 days post-injection. To determine whether predatory bacteria could reduce bacterial burden in vivo, Klebsiella pneumoniae was injected into the tail veins of rats and followed with multiple doses of predatory bacteria over 16 or 24 hours. Predatory bacteria were unable to significantly reduce K. pneumoniae burden in the blood or prevent dissemination to other organs. The results suggest that predatory bacteria may not be effective for treatment of acute blood infections.

Effects of four kinds of electromagnetic fields (EMF) with different frequency spectrum bands on ovariectomized osteoporosis in mice

Electromagnetic fields (EMF) was considered as a non-invasive modality for treatment of osteoporosis while the effects were diverse with EMF parameters in time domain. In present study, we extended analysis of EMF characteristics from time domain to frequency domain, aiming to investigate effects of four kinds of EMF (LP (1–100 Hz), BP (100–3,000 Hz), HP (3,000–50,000 Hz) and AP (1–50,000 Hz)) on ovariectomized (OVX) osteoporosis (OP) in mice. Forty-eight 3-month-old female BALB/c mice were equally assigned to Sham, OVX, OVX + LP, OVX + BP, OVX + HP and OVX + AP groups (n = 8). After 8-week exposure (3 h/day), LP and BP significantly increased serum bone formation markers and osteogenesis-related gene expressions compared with OVX. Bedsides, LP and BP also slightly increased bone resorption activity compared with OVX, evidenced by increased RANKL/OPG ratio. HP sharply decreased serum bone formation and resporption markers and osteogenesis and osteoclastogenesis related gene expressions compared with OVX. AP had accumulative effects of LP, BP and HP, which significantly increased bone formation and decreased bone resporption activity compared with OVX. As a result, LP, BP and HP exposure did not later deterioration of bone mass, microarchitecture and mechanical strength in OVX mice with OP. However, AP stimulation attenuated OVX-induced bone loss.

Potential role of biochars in decreasing soil acidification - A critical review

A large number of soils, worldwide, are acid (normally pH<5.5) and suffering from on-going soil acidification. Acid soils or soils undergoing acidification generally have low fertility and low crop productivity. Biochars have been reported to be of potential value in agriculture for improving soil properties and in reducing the hazards caused by soil acidification and in naturally acidic soils. However, the ameliorant effects of biochars on acid soils and the mechanisms involved have not previously been critically reviewed. Here we summarize the phenomena, and mechanisms involved in the improvement of soil acidity by biochars, the alleviation of aluminum toxicity, the enhancement of nutrient availability, and changes in nitrification by collating data in the literature. In addition, the agronomic effectiveness and environmental concerns in the incorporation of biochar and other soil additives (i.e. lime, industrial by-products, organic wastes and plant residues) to acid soils are systemically compared. We conclude that biochar is a potentially effective amendment to reverse or to prevent acidification in acid soils. Finally, perspectives for further research in terms of soil acidification are presented to address some issues that are still poorly understood and/or highly controversial.

Giant frequency down-conversion of the dancing acoustic bubble

We have demonstrated experimentally the existence of a giant frequency down-conversion of the translational oscillatory motion of individual submillimeter acoustic bubbles in water in the presence of a high frequency (500 kHz) ultrasonic standing wave. The frequency of the translational oscillations (~170 Hz) is more than three orders of magnitude smaller than that of the driving acoustic wave. We elucidate the mechanism of this very slow oscillation with an analytical model leading to an equation of translational motion of a bubble taking the form of Mathieu's equation. This equation illuminates the origin of the giant down conversion in frequency as arising from an unstable equilibrium. We also show that bubbles that form chains along the direction of the acoustic standing wave due to radiation interaction forces exhibit also translation oscillations that form a spectral band. This band extends approximately from 130 Hz up to nearly 370 Hz, a frequency range that is still at least three orders of magnitude lower than the frequency of the driving acoustic wave.

Predatory Bacteria Attenuate Klebsiella pneumoniae Burden in Rat Lungs

Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus are predatory bacteria that naturally-and obligately-prey on other Gram-negative bacteria, and their use has been proposed as a potential new approach to control microbial infection. The ability of predatory bacteria to prey on Gram-negative human pathogens in vitro is well documented; however, the in vivo safety and efficacy of predatory bacteria have yet to be fully assessed. In this study, we examined whether predatory bacteria can reduce bacterial burden in the lungs in an in vivo mammalian system. Initial safety studies were performed by intranasal inoculation of rats with predatory bacteria. No adverse effects or lung pathology were observed in rats exposed to high concentrations of predatory bacteria at up to 10 days postinoculation. Enzyme-linked immunosorbent assay (ELISA) of the immune response revealed a slight increase in inflammatory cytokine levels at 1 h postinoculation that was not sustained by 48 h. Additionally, dissemination experiments showed that predators were efficiently cleared from the host by 10 days postinoculation. To measure the ability of predatory bacteria to reduce microbial burden in vivo, we introduced sublethal concentrations of Klebsiella pneumoniae into the lungs of rats via intranasal inoculation and followed with multiple doses of predatory bacteria over 24 h. Predatory bacteria were able to reduce K. pneumoniae bacterial burden, on average, by more than 3.0 log10 in the lungs of most rats as measured by CFU plating. The work presented here provides further support for the idea of developing predatory bacteria as a novel biocontrol agent.

IMPORTANCE

A widely held notion is that antibiotics are the greatest medical advance of the last 50 years. However, the rise of multidrug-resistant (MDR) bacterial infections has become a global health crisis over the last decade. As we enter the postantibiotic era, it is crucial that we begin to develop new strategies to combat bacterial infection. Here, we report one such new approach: the use of predatory bacteria (Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus) that naturally-and obligately-prey on other Gram-negative bacteria. To our knowledge, this is the first study that demonstrated the ability of predatory bacteria to attenuate the bacterial burden of a key human pathogen in an in vivo mammalian system. As the prevalence of MDR infections continues to rise each year, our results may represent a shift in how we approach treating microbial infections in the future.

944 mJ Nd:YAG planar waveguide laser amplifier with the optical to optical efficiency of 52

We demonstrated a quasi-continuous wave (QCW) Nd:YAG planar waveguide laser amplifier with the single pulse output energy of 944 mJ. At the pulse repetition frequency (PRF) of 100 Hz, 1064 nm seed laser was coupled into the planar waveguide laser amplifier with the single pulse energy of 128 mJ and the pulse duration of 192 μs. With the total pump energy of 1582 mJ, the extracted energy of 816 mJ was obtained, leading to an optical to optical efficiency of 52% and an electrical to optical efficiency of 28%. To the best our knowledge, it is up to now the highest efficiency and output energy in Nd:YAG planar waveguide laser amplifier reported. At the maximum output, the beam quality factors M2 were measured to be 3.44 and 4.81 in the guided direction and unguided direction respectively, and the polarization degree was 98.6%. Higher average power could be obtained with the better performance of seeder oscillator.

The Prevalence, Clinical, and Molecular Characteristics of Congenital Hypothyroidism Caused by DUOX2 Mutations: A Population-Based Cohort Study in Guangzhou

Thyroid dyshormonogenesis (DH) has recently been reported to be more frequently associated with mutations in the dual oxidase 2 (DUOX2) gene. The present study was aimed to investigate the prevalence, clinical, and molecular characteristics of congenital hypothyroidism (CH) caused by DUOX2 mutations in Guangzhou. A population-based cohort of 156 patients with CH was recruited based on neonatal screening among 433 578 newborns born in Guangzhou from 2011 to 2012. Genetic analysis of DUOX2 was performed in 96 patients with suspected thyroid dyshormonogenesis (SDH) by PCR-amplified direct sequencing. Apart from 2 cases without ultrasonographic data, 118 (76.6%) of the 156 patients were classified as SDH and 36 (23.4%) as thyroid dysgenesis (TD) according to thyroid ultrasound at diagnosis. Genetic analysis revealed 23 different variants in 60 unrelated individuals (60/96, 62.5%), including 13 novel variants that were absent from HGMD, dbSNP databases, and the 50 normal controls. The novel missense variants were predicted to be pathogenic by SIFT and PolyPhen-2. The p.K530X was the most common mutation. Ninety-three percent of mutant alleles occurred in exons 5, 6, 9, 14, 17, 20, 25, 27, and 28. There were no significant differences in phenotypes between biallelic and monoallelic variants cases or between with-DUOX2 and non-DUOX2 variants cases. Most patients with DUOX2 defects (78.2%) were transient CH. In conclusion, the prevalence of DUOX2 pathogenic variants was high (62.5%) in this cohort. Thirteen novel probably pathologic variants were reported. The p.K530X was the most common mutation in the Chinese population. There was no correlation between DUOX2 genotypes and clinical phenotypes.

Effect of Predatory Bacteria on Human Cell Lines

Predatory bacteria are Gram-negative bacteria that prey on other Gram-negative bacteria and have been considered as potential therapeutic agents against multi-drug resistant pathogens. In vivo animal models have demonstrated that predatory bacteria are non-toxic and non-immunogenic in rodents. In order to consider the use of predatory bacteria as live antibiotics, it is important to investigate their effect on human cells. The aim of this study was to determine the effect of Bdellovibrio bacteriovorus strains 109J and HD100, and Micavibrio aeruginosavorus strain ARL-13 on cell viability and inflammatory responses of five human cell lines, representative of clinically relevant tissues. We found that the predators were not cytotoxic to any of the human cell lines tested. Microscopic imaging showed no signs of cell detachment, as compared to predator-free cells. In comparison to an E. coli control, exposure to higher concentrations of the predators did not trigger a significant elevation of pro-inflammatory cytokines in four of the five human cell lines tested. Our work underlines the non-pathogenic attributes of predatory bacteria on human cells and highlights their potential use as live antibiotics against human pathogens.

Lubricity of gold nanocrystals on graphene measured using quartz crystal microbalance

In order to test recently predicted ballistic nanofriction (ultra-low drag and enhanced lubricity) of gold nanocrystals on graphite at high surface speeds, we use the quartz microbalance technique to measure the impact of deposition of gold nanocrystals on graphene. We analyze our measurements of changes in frequency and dissipation induced by nanocrystals using a framework developed for friction of adatoms on various surfaces. We find the lubricity of gold nanocrystals on graphene to be even higher than that predicted for the ballistic nanofriction, confirming the enhanced lubricity predicted at high surface speeds. Our complementary molecular dynamics simulations indicate that such high lubricity is due to the interaction strength between gold nanocrystals and graphene being lower than previously assumed for gold nanocrystals and graphite.

Tristetraprolin: a novel mediator of the anticancer properties of resveratrol

Resveratrol is a natural compound that exhibits anticancer properties. Previous studies have proved that it can inhibit the proliferation of breast cancer cell lines and upregulate some cytokines such as cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF). The initiation and progression of cancer are associated with the abnormal expression of multiple cytokines. Tristetraprolin (TTP), an mRNA-binding protein, is one of the key proteins that participate in regulating cytokine expression. Two different proliferation assays on MCF-7 cells showed that the cell proliferation rate significantly reduced following treatment with resveratrol. Most importantly, we found that resveratrol promoted TTP expression at both the mRNA and protein level in a dose- and time-dependent manner. In addition, the expression of COX-2 and VEGF were significantly suppressed by resveratrol while that of inducible nitric oxide synthase (iNOS) was upregulated. Lastly, the effects of resveratrol on both MCF-7 proliferation and expression of COX-2, VEGF, and iNOS were significantly inhibited by TTP knockdown, indicating that TTP mediates the anticancer properties of resveratrol. In summary, we conclude that resveratrol inhibits the proliferation of MCF-7 cells by TTP upregulation, which is associated with downregulation of COX-2 and VEGF and upregulation of iNOS.

Value of the Gastroesophageal Reflux Disease Questionnaire (GerdQ) in predicting the proton pump inhibitor response in coronary artery disease patients with gastroesophageal reflux-related chest pain

Chest pain experienced by patients with coronary artery disease can be partly due to gastroesophageal reflux-induced chest pain (GERP). Empirical proton pump inhibitor (PPI) therapy has been recommended as an initial clinical approach for treating GERP. However, PPI use may lead to some health problems. The Gastroesophageal Reflux Disease Questionnaire (GerdQ) may represent a noninvasive and cost-effective approach for avoiding PPI misuse and for identifying the appropriate patients for the PPI trial test. The aim of this pilot study was to prospectively evaluate the association between GerdQ scores and PPI response in patients with coronary artery disease (CAD) and GERP to determine whether the GerdQ predicts the PPI response in patients with CAD and GERP and to further validate the clinical application value of the GerdQ. A total of 154 consecutive patients with potential GERP were recruited to complete a GerdQ with subsequent PPI therapy. Based on the PPI trial result, patients were divided into a PPI-positive response group and a PPI-negative response group. The difference in the GerdQ scores between the two groups was assessed. The receiver operating characteristic (ROC) curve of GerdQ score was drawn according to the PPI response as the gold standard. The ability of GerdQ to predict the PPI response was assessed. A total of 96 patients completed the entire study; 62 patients (64.6%) were assigned to the PPI-positive response group, and 34 patients (35.4%) to the PPI-negative response group. The GerdQ score of the PPI-positive response group (8.11 ± 3.315) was significantly higher than that of the PPI-negative response group (4.41 ± 2.743), and the difference was statistically significant (t = 5.863, P = 0.000). The ROC curve was drawn according to a PPI response assessment result with a score above 2 as the gold standard. The area under curve was 0.806. When the critical value of GerdQ score was 7.5, Youden index was up to 0.514, the diagnostic sensitivity was 0.661, and the diagnostic specificity was 0.853. A GerdQ score greater than 7.5 better predicts the response to the PPI trial therapy. There is a strong association between the GerdQ score and the response to PPI therapy. Higher GerdQ scores were predictive of a positive PPI response in CAD patients with GERP. The GerdQ may be a reasonable screening tool for GERP in patients with CAD who are prepared to accept PPI therapy.

Interaction of an Ultrarelativistic Electron Bunch Train with a W-Band Accelerating Structure: High Power and High Gradient

Electron beam interaction with high frequency structures (beyond microwave regime) has a great impact on future high energy frontier machines. We report on the generation of multimegawatt pulsed rf power at 91 GHz in a planar metallic accelerating structure driven by an ultrarelativistic electron bunch train. This slow-wave wakefield device can also be used for high gradient acceleration of electrons with a stable rf phase and amplitude which are controlled by manipulation of the bunch train. To achieve precise control of the rf pulse properties, a two-beam wakefield interferometry method was developed in which the rf pulse, due to the interference of the wakefields from the two bunches, was measured as a function of bunch separation. Measurements of the energy change of a trailing electron bunch as a function of the bunch separation confirmed the interferometry method.

Electrochemistry-based approaches to low cost, high sensitivity, automated, multiplexed protein immunoassays for cancer diagnostics

Early detection and reliable diagnostics are keys to effectively design cancer therapies with better prognoses. The simultaneous detection of panels of biomarker proteins holds great promise as a general tool for reliable cancer diagnostics. A major challenge in designing such a panel is to decide upon a coherent group of biomarkers which have higher specificity for a given type of cancer. The second big challenge is to develop test devices to measure these biomarkers quantitatively with high sensitivity and specificity, such that there are no interferences from the complex serum or tissue matrices. Lastly, integrating all these tests into a technology that does not require exclusive training to operate, and can be used at point-of-care (POC) is another potential bottleneck in futuristic cancer diagnostics. In this article, we review electrochemistry-based tools and technologies developed and/or used in our laboratories to construct low-cost microfluidic protein arrays for the highly sensitive detection of a panel of cancer-specific biomarkers with high specificity which at the same time has the potential to be translated into POC applications.

Effects of extremely low frequency pulsed magnetic fields on diabetic nephropathy in streptozotocin-treated rats

Background

Extremely low frequency pulsed magnetic fields (ELFPMF) have been shown to induce Faraday currents and measurable effects on biological systems. A kind of very high frequency electromagnetic field was reported that it improved the symptoms of diabetic nephropathy (DN) which is a major complication of diabetes. However, few studies have examined the effects of ELFPMF DN at the present. The present study was designed to investigate the effects of ELFPMF on DN in streptozotocin (STZ)–induced type 1 diabetic rats.

Methods

Adult male SD rats were randomly divided into three weight-matched groups: Control (non-diabetic rats without DN), DN + ELFPMF (diabetic rats with DN exposed to ELFPMF, 8 h/days, 6 weeks) and DN (diabetic rats with DN exposed to sham ELFPMF). Renal morphology was examined by light and electron microscopy, vascular endothelial growth factor (VEGF)-A and connective tissue growth factor (CTGF) were measured by enzyme linked immune sorbent assay.

Results

After 6 weeks’ ELFPMF exposure, alterations of hyperglycemia and weight loss in STZ-treated rats with DN were not found, while both positive and negative effects of ELFPMF on the development of DN in diabetic rats were observed. The positive one was that ELFPMF exposure attenuated the pathological alterations in renal structure observed in STZ-treated rats with DN, which were demonstrated by slighter glomerular and tubule-interstitial lesions examined by light microscopy and slighter damage to glomerular basement membrane and podocyte foot processes examined by electron microscopy. And then, the negative one was that ELFPMF stimulation statistically significantly decreased renal expression of VEGF-A and statistically significantly increased renal expression of CTGF in diabetic rats with DN, which might partially aggravate the symptoms of DN.

Conclusion

Both positive and negative effects of ELFPMF on the development of DN in diabetic rats were observed. The positive effect induced by ELFPMF might play a dominant role in the procession of DN in diabetic rats, and it is suggested that the positive effect should be derived from the correction of pathogenic diabetes-induced mediators.

Association between genetic variants of EGF-containing fibulin-like extracellular matrix protein1 gene and sporadic breast cancer in a Chinese Han population

PURPOSE OF INVESTIGATION

Genetic susceptibility of breast cancer has been shown to be modulated by inheritance of polymorphic genes. EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) gene played an important role in many tumors, including lung cancer, hepatic carcinoma, and prostate cancer. In addition, it was importantly downexpressed in breast cancer. The present research aimed to assess the association between genetic variations of EFEMP1 and breast cancer risk.

MATERIALS AND METHODS

The authors genotyped 11 common tagging SNPs with an array platform including 960 cases and 972 cancer-free controls of Chinese women, according to the HapMap database based on the pairwise linkage disequilibrium (LD) r² threshold of 0.8, minor allele frequency of 0.05.

RESULTS

Three SNPs were significant associated with breast cancer (rs3791679, p = 0.016, OR = 1.21, 95% CI = 1.04-1.41; rs1346786, p = 0.005, OR = 1.31, 95% CI = 1.08 -1.59; rs727878, p = 0.002, OR = 1.29, 95%CI = 1.10-1.51). Multivariate logistic regression analysis revealed that, compared with wild-type carriers in a dominant model, a significantly increased breast cancer risk was associated with the three identified risk SNPs. Among the selected tagging SNPs, three haplotype blocks were identified, and the results of haplotype analysis were consistent with the single-locus analysis. The haplotype 'GG' in block 1 and haplotype 'AG' in block 2 were significantly associated with breast cancer, and had a 54% and 28% increased breast cancer risk respectively, compared with their corresponding noncarriers.

CONCLUSIONS

The present results suggested that the polymorphisms of EFEMP1 gene were associated with breast cancer and might contribute to the susceptibility of the progression of breast cancer in Chinese Han women. Individuals with the risk alleles might increase the risk of breast cancer.