Experimental study of single-pin puncture asymmetrical hydroablation using a conformational radiofrequency ablation electrode in ex vivo ox liver

OBJECTIVE

The aim of this study was to evaluate the feasibility of single-pin puncture asymmetrical hydroablation in liver using the multipole cluster conformable radiofrequency ablation electrode.

METHODS

The conformable electrode used in this study consists of both a main electrode in a central cannula and a circle of subelectrodes comprising two groups of six subelectrodes located on opposite sides (A and B) of the circle. The two subelectrode groups can be extended to different lengths independently of one another, resulting in asymmetrical shapes. Ablation experiments were performed using ex vivo ox liver. The experiments included six groups based on six potential electrode deployments in which the subelectrodes on sides A and B were fully extended, half extended or fully retracted. After ablation, the transverse diameters of the resulting necrotic tissue from sides A and B were measured. The experiment was conducted in 12 separate sites for each group.

RESULTS

When the subelectrodes were arranged symmetrically (either fully extended or half extended on both sides), the mean transverse diameter of necrotic tissue was similar for both sides A and B. When the subelectrodes were arranged asymmetrically, the fully extended side showed a significantly greater mean transverse diameter of necrotic tissue than the half extended or fully retracted side.

CONCLUSION

In this study, the WHK 3-8-4 multipole cluster conformable radiofrequency ablation electrode was able to produce both symmetrical and asymmetrical necrotic tissue patterns in the liver.

ADVANCES IN KNOWLEDGE

The size and shape of the ablation can be altered by both withdrawing and extending the subelectrodes to different lengths.

[Study on the genetic differences among Oncomelania hupensis population in middle and lower reaches of Yangtze River using microsatellite DNA markers]

OBJECTIVE

To identify the genetic structure of Oncomelania hupensis in the middle and lower reaches of Yangtze River by using microsatellite DNA molecular markers.

METHODS

O. hupensis snails were collected from the provinces of Anhui, Hunan, Hubei, Jiangxi, and Jiangsu, of which 6 polymorphic microsatellite DNA loci (P84, T5-13, T5-11, T4-22, T6-27 and P82) were amplified with fluorescence labeled universal primer. 20-50 snail samples were collected at each spot, adding up to 165 samples. The number of alleles (N(alpha)), inbreeding coefficient (F(IS)), heterozygosity (H), fixation index (F(ST)) of each group snails, genetic distance between/groups, and the polymorphic information content (PIC) were calculated. Cluster analysis was then carried out based on genetic distance, and hierarchical AMOVA calculation was done.

RESULTS

The number of alleles in each population ranged from 3 to 33, and the inbreeding coefficient ranged from 0.143 to 0.539. The average expected heterozygosity and observed heterozygosity ranged from 0.600 to 0.883 and 0.308 to 0.759, respectively, being the highest in Hubei population and the lowest in Jiangsu population. The range of F(ST) value between paired populations was from 0.0006 to 0.0531. The small F(ST) value suggested that genetic differentiation did not occur among the populations. The average polymorphic information content in the populations ranged from 0.511 to 0.850, showing a high polymorphism except the Jiangsu population. Hierarchical AMOVA calculations showed that inter-individual variation of the snails occupied 95.2% of the total variations. Cluster analysis revealed that Anhui group clustered first to Jiangsu, followed with Hunan, Jiangxi and Hubei.

CONCLUSION

There is a rich diversity in O. hupensis. Cluster analysis shows a consistency with the geographical distribution pattern. The genetic differences among the 5 snail populations are trivial with microsatellite DNA variation mostly present in individuals.

Measurement of relative branching fractions of B decays to ψ(2S) and J/ψ mesons

The relative rates of B-meson decays into J/ψ and ψ(2S) mesons are measured for the three decay modes in pp collisions recorded with the LHCb detector. The ratios of branching fractions ([Formula: see text]) are measured to be [Formula: see text] where the third uncertainty is from the ratio of the ψ(2S) and J/ψ branching fractions to μ⁺μ^-.

Bidentate surface structures of glycylglycine on Si(111)7×7 by high-resolution scanning tunneling microscopy: site-specific adsorption via N-H and O-H or double N-H dissociation

The early adsorption stage of glycylglycine on Si(111)7×7 surface has been studied by scanning tunneling microscopy (STM). Filled-state imaging shows that glycylglycine adsorbs dissociatively in a bidentate fashion on two adjacent Si adatoms across a dimer wall or an adatom-restatom pair, with the dissociated H atoms on neighboring restatoms. The present STM result validates our hypothesis that both bidentate configurations involving N-H and O-H dissociation and double N-H dissociation are equally probable. Our STM results further show that the relative surface concentrations of the five bidentate configurations follow a specific ordering. This suggests that N-H dissociation at a center adatom site would likely be followed by N-H dissociation at an adjacent restatom, while N-H dissociation at a corner adatom site would be succeeded by O-H dissociation at an adatom across the dimer wall. Evidently, the strong bidentate interactions also inhibit surface diffusion of the adsorbed glycylglycine fragment, and the adsorption apparently follows random sequential adsorption statistics. The random nature of adsorption is also supported by the similar relative occupancies of the center adatom and corner adatom sites, indicating that the relative reactivities of these adatom sites do not play a significant role. Our DFT computational study shows that all three bidentate (Si-)NHCH(2)CONHCH(2)COO(-Si) adatom-adatom configurations (center-center, corner-corner, center-corner) have similar adsorption energies for a double adatom-adatom pair across the dimer wall, while the (Si-)NHCH(2)CON(-Si)CH(2)COOH bidentate adatom-restatom configuration is energetically favorable. The free -CONH- and -COOH groups remaining on the respective bidentate adstructures could facilitate adsorption of the second adlayer through the formation of hydrogen bonding.

Inter-rater reliability between musculoskeletal radiologists and orthopedic surgeons on computed tomography imaging features of spinal metastases

INTRODUCTION

The primary objective of this pilot study was to examine the inter-rater reliability in scoring the computed tomography (ct) imaging features of spinal metastases in patients referred for radiotherapy (rt) for bone pain.

METHODS

In a retrospective review, 3 musculoskeletal radiologists and 2 orthopedic spinal surgeons independently evaluated ct imaging features for 41 patients with spinal metastases treated with rt in an outpatient radiation clinic from January 2007 to October 2008. The evaluation used spinal assessment criteria that had been developed in-house, with reference to osseous and soft tissue tumour extent,presence of a pathologic fracture,severity of vertebral height loss, andpresence of kyphosis.The Cohen kappa coefficient between the two specialties was calculated.

RESULTS

Mean patient age was 69.2 years (30 men, 11 women). The mean total daily oral morphine equivalent was 73.4 mg. Treatment dose-fractionation schedules included 8 Gy/1 (n = 28), 20 Gy/5 (n = 12), and 20 Gy/8 (n = 1). Areas of moderate agreement in identifying the ct imaging appearance of spinal metastasis included extent of vertebral body involvement (κ = 0.48) and soft-tissue component (κ = 0.59). Areas of fair agreement included extent of pedicle involvement (κ = 0.28), extent of lamina involvement (κ = 0.35), and presence of pathologic fracture (κ = 0.20). Areas of poor agreement included nerve-root compression (κ = 0.14) and vertebral body height loss (κ = 0.19).

CONCLUSIONS

The range of agreement between musculoskeletal radiologists and orthopedic surgeons for most spinal assessment criteria is moderate to poor. A consensus for managing challenging vertebral injuries secondary to spinal metastases needs to be established so as to best triage patients to the most appropriate therapeutic modality.

The stretchability of Mozzarella cheese evaluated by a temperature-controlled 3-prong hook test

Stretchability is one of the most important functional properties of Mozzarella cheese, but no objective and widely accepted technique exists for evaluation; most of the cheese stretchability tests are influenced by the ambient conditions. This paper demonstrates a technique, which is novel and relatively simple, to evaluate the stretchability of Mozzarella cheese objectively. In an oil bath, melted cheese is stretched by a hook probe, controlled by an Instron tensile tester (Instron Corp., Norwood, MA); cheese strands are lifted from the melted cheese reservoir to a stretch length of 300 mm, when the load and extension data are recorded by the Instron tensile tester. This test overcomes other tests' drawbacks, such as subjective stretching speeds and variations in ambient temperature and humidity. Through the test comparison on standard Mozzarella, the modified stretching test in an oil bath has greater repeatability than the original test without oil bath. From the load and extension curve, the yield load is measured to evaluate the stretchability. In the meantime, the inversion point extension of necking is also measured based on polymer study, producing more repeatable results than the yield load. The modified 3-prong hook test was applied to Mozzarella cheese samples with different processing conditions, including the screw conditions (screw time, speed, and temperature), draining pH, calcium content, and fat content, and significant differences were found between these samples and the control sample.

Measurement of ψ(2S) meson production in pp collisions at [Formula: see text]

The differential cross-section for the inclusive production of ψ(2S) mesons in pp collisions at [Formula: see text] has been measured with the LHCb detector. The data sample corresponds to an integrated luminosity of 36 pb^-1. The ψ(2S) mesons are reconstructed in the decay channels ψ(2S)→μ⁺μ^- and ψ(2S)→J/ψπ⁺π^-, with the J/ψ meson decaying into two muons. Results are presented both for promptly produced ψ(2S) mesons and for those originating from b-hadron decays. In the kinematic range p_T(ψ(2S))≤16 GeV/c and 2<y(ψ(2S))≤4.5 we measure [Formula: see text] where the last uncertainty on the prompt cross-section is due to the unknown ψ(2S) polarization. Recent QCD calculations are found to be in good agreement with our measurements. Combining the present result with the LHCb J/ψ measurements we determine the inclusive branching fraction [Formula: see text] where the last uncertainty is due to the [Formula: see text], [Formula: see text] and [Formula: see text] branching fraction uncertainties.

Intranasal administration of TAT-haFGF(₁₄₋₁₅₄) attenuates disease progression in a mouse model of Alzheimer's disease

Human acidic fibroblast growth factor (haFGF), a neurotrophin-like growth factor in the brain, plays important roles in the development, differentiation and regeneration of brain neurons, which makes it potential to treat Alzheimer's disease (AD). In this study, haFGF(14-154) and TAT-haFGF(14-154) (haFGF(14-154) fused with the cell-penetrating peptide transactivator of transcription protein transduction domain (TAT-PTD)) were intranasally administrated for 5 weeks to investigate the effects on senescence-accelerated mouse prone-8 (SAMP8) mice (a mouse model of AD). Results showed that TAT-PTD could increase the concentration of haFGF in the brain significantly, and TAT-haFGF(14-154) was more effective than haFGF(14-154) in the same dosage (300 μg/kg). Importantly, TAT-haFGF(14-154) improved the learning and memory abilities of SAMP8 mice in the behavioral test, and promoted the function of cholinergic system by measuring the relevant biomarkers (acetylcholine (ACh) level, acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities). TAT-haFGF(14-154) also significantly reduced β-amyloid protein(1-42) (Aβ(1-42)) deposits as well as the levels of Aβ soluble forms in the mice brains and prevented the neurons from apoptosis. Besides, the oxidative stress impairment in the brain and serum was also ameliorated. The results suggest that TAT-haFGF(14-154) could attenuate the disease progression of SAMP8 AD mice, and the mechanism is related to the regulation of neurons microenvironment including neurotransmitters, Aβ pathology and oxidative stress.

The impact of forced joint exercise on lubricin biosynthesis from articular cartilage following ACL transection and intra-articular lubricin's effect in exercised joints following ACL transection

OBJECTIVE

To evaluate the impact of forced joint exercise following acute knee injury on lubricin metabolism and its relationship to cartilage degeneration and to assess chondroprotection of a single-dose purified human lubricin injection in exercised injured joints.

METHODS

Anterior cruciate ligament transection (ACLT) was performed in rats with six experimental groups; 3-week post-ACLT, 3-week post-ACLT + exercise, 5-week post-ACLT, 5-week post-ACLT + exercise, and 5-week post-ACLT + exercise treated with intra-articular phosphate buffered saline (PBS) or lubricin. Joint exercise was achieved using a rotating cylinder at a speed of 6 rpm for 30 min daily, 5 days a week starting 1 week following surgery. Cartilage lubricin expression in injured joints was determined. Histological analyses included Safranin O/Fast Green, activated caspase-3, and lubricin mRNA in-situ hybridization. Assessment of cartilage damage was performed by osteoarthritis research society international (OARSI) modified Mankin scoring and urinary CTXII (uCTXII) levels.

RESULTS

At 3 weeks, lubricin expression in exercised ACLT joints was significantly (P < 0.001) lower compared to ACLT joints. The OARSI scores were significantly (P < 0.001) higher in the ACLT + exercise animals compared to ACLT animals at 5 weeks. Compared to 3-week ACLT, 3-week ACLT + exercise cartilage showed increased caspase-3 staining. Compared to ACLT + exercise and PBS-treated ACLT + exercise, lubricin intra-articular treatment resulted in a significant increase (P < 0.001) in cartilage lubricin gene expression and a reduction (P < 0.05) in uCTXII levels.

CONCLUSION

Joint exercise resulted in decreased lubricin cartilage expression, increased cartilage degeneration and reduced superficial zone chondrocyte viability in the ACLT joint. Intra-articular lubricin administration ameliorated cartilage damage due to exercise and preserved superficial zone chondrocytes' viability.

NPY modulates PYY function in the regulation of energy balance and glucose homeostasis

AIMS

Both the neuronal-derived neuropeptide Y (NPY) and the gut hormone peptide YY (PYY) have been implicated in the regulation of energy balance and glucose homeostasis. However, despite similar affinities for the same Y receptors, the co-ordinated actions of these two peptides in energy and glucose homeostasis remain largely unknown.

METHODS

To investigate the mechanisms and possible interactions between PYY with NPY in the regulation of these processes, we utilized NPY/PYY single and double mutant mouse models and examined parameters of energy balance and glucose homeostasis.

RESULTS

PYY(-/-) mice exhibited increased fasting-induced food intake, enhanced fasting and oral glucose-induced serum insulin levels, and an impaired insulin tolerance, - changes not observed in NPY(-/-) mice. Interestingly, whereas PYY deficiency-induced impairment in insulin tolerance remained in NPY(-/-) PYY(-/-) mice, effects of PYY deficiency on fasting-induced food intake and serum insulin concentrations at baseline and after the oral glucose bolus were absent in NPY(-/-) PYY(-/-) mice, suggesting that NPY signalling may be required for PYY's action on insulin secretion and fasting-induced hyperphagia. Moreover, NPY(-/-) PYY(-/-) , but not NPY(-/-) or PYY(-/-) mice had significantly decreased daily food intake, indicating interactive control by NPY and PYY on spontaneous food intake. Furthermore, both NPY(-/-) and PYY(-/-) mice showed significantly reduced respiratory exchange ratio during the light phase, with no additive effects observed in NPY(-/-) PYY(-/-) mice, indicating that NPY and PYY may regulate oxidative fuel selection via partly shared mechanisms. Overall, physical activity and energy expenditure, however, are not significantly altered by NPY and PYY single or double deficiencies.

CONCLUSIONS

These findings show significant and diverse interactions between NPY and PYY signalling in the regulation of different aspects of energy balance and glucose homeostasis.

Learning Chronobiology by Improving Wikipedia

Although chronobiology is of growing interest to scientists, physicians, and the general public, access to recent discoveries and historical perspectives is limited. Wikipedia is an online, user-written encyclopedia that could enhance public access to current understanding in chronobiology. However, Wikipedia is lacking important information and is not universally trusted. Here, 46 students in a university course edited Wikipedia to enhance public access to important discoveries in chronobiology. Students worked for an average of 9 h each to evaluate the primary literature and available Wikipedia information, nominated sites for editing, and, after voting, edited the 15 Wikipedia pages they determined to be highest priorities. This assignment ( http://www.nslc.wustl.edu/courses/Bio4030/wikipedia_project.html ) was easy to implement, required relatively short time commitments from the professor and students, and had measurable impacts on Wikipedia and the students. Students created 3 new Wikipedia sites, edited 12 additional sites, and cited 347 peer-reviewed articles. The targeted sites all became top hits in online search engines. Because their writing was and will be read by a worldwide audience, students found the experience rewarding. Students reported significantly increased comfort with reading, critiquing, and summarizing primary literature and benefited from seeing their work edited by other scientists and editors of Wikipedia. We conclude that, in a short project, students can assist in making chronobiology widely accessible and learn from the editorial process.

Comparative analysis of the role of JNK signaling pathway in regulating cell proliferation and apoptosis of rat liver regeneration and rat acute hepatic failure

To compare the role of JNK signaling pathway in rat liver regeneration (LR) and in rat acute hepatic failure (AHF) occurrence at the gene transcription level, Rat Genome 230 2.0 array was used to detect the gene expression profiles of the two processes, and bioinformatics and systems biology methods were applied to analyze the physiological activities uncovered by their gene expression profiles in this study. The results showed that 240 genes were included in the array above, though there were 302 genes related to forty two paths of JNK signaling pathway. Array detection results demonstrated that 52 genes were significantly expressed during LR, 20 genes in AHF occurrence, and 15 genes in both of above two processes. Synergy values of these genes were calculated using a mathematical model established by our lab, which revealed the following. The cell proliferation-promoting effects of paths 1, 16 and paths 1-17 of JNK signaling pathway were stronger than the control at 6-12 h and 72 h of LR, respectively, while the cell proliferation-promoting effects of paths 1-17 and the cell proliferation-inhibiting effects of path 34-35 were weaker at 6h of AHF occurrence. The cell apoptosis-promoting effects of paths 22-23 were much stronger at 6, 12 and 72 h of LR and at 12, 24 h of AHF occurrence. In conclusion, thirty eight paths of JNK signaling pathway regulate cell proliferation and apoptosis in both LR and AHF occurrence.