A mathematical model of the murine ventricular myocyte: a data-driven biophysically based approach applied to mice overexpressing the canine NCX isoform

Mathematical modeling of Ca(2+) dynamics in the heart has the potential to provide an integrated understanding of Ca(2+)-handling mechanisms. However, many previous published models used heterogeneous experimental data sources from a variety of animals and temperatures to characterize model parameters and motivate model equations. This methodology limits the direct comparison of these models with any particular experimental data set. To directly address this issue, in this study, we present a biophysically based model of Ca(2+) dynamics directly fitted to experimental data collected in left ventricular myocytes isolated from the C57BL/6 mouse, the most commonly used genetic background for genetically modified mice in studies of heart diseases. This Ca(2+) dynamics model was then integrated into an existing mouse cardiac electrophysiology model, which was reparameterized using experimental data recorded at consistent and physiological temperatures. The model was validated against the experimentally observed frequency response of Ca(2+) dynamics, action potential shape, dependence of action potential duration on cycle length, and electrical restitution. Using this framework, the implications of cardiac Na(+)/Ca(2+) exchanger (NCX) overexpression in transgenic mice were investigated. These simulations showed that heterozygous overexpression of the canine cardiac NCX increases intracellular Ca(2+) concentration transient magnitude and sarcoplasmic reticulum Ca(2+) loading, in agreement with experimental observations, whereas acute overexpression of the murine cardiac NCX results in a significant loss of Ca(2+) from the cell and, hence, depressed sarcoplasmic reticulum Ca(2+) load and intracellular Ca(2+) concentration transient magnitude. From this analysis, we conclude that these differences are primarily due to the presence of allosteric regulation in the canine cardiac NCX, which has not been observed experimentally in the wild-type mouse heart.

A pilot study of the clinical relevance of the relationship between the serum level of pregnancy-associated plasma protein A and the degree of acute coronary syndrome

Serum levels of pregnancy-associated plasma protein-A (PAPP-A), high-sensitivity C-reactive protein (hs-CRP) and tumour necrosis factor-alpha (TNF-alpha) were measured in 70 patients with acute coronary syndrome (ACS), comprising 18 with unstable angina (UA), 37 with acute myocardial infarction (AMI) and 15 with stable angina (SA); 15 healthy controls were also included. Levels of PAPP-A were significantly higher in the UA and AMI groups than in the SA and control groups. Levels of PAPP-A were similar in the SA and control groups, and higher in the ACS patients who were cardiac troponin T-negative (comprising UA and AMI patients) than in the control and SA groups. Levels of hs-CRP and TNF-alpha were significantly higher in the SA group than in the control group, significantly higher in the UA group than in the SA and control groups, and significantly higher in the AMI group than in all other groups. Levels of PAPP-A in ACS patients were positively correlated with levels of hs-CRP and TNF-alpha. It would seem, therefore, that PAPP-A is associated with inflammation and might be used to detect plaque instability and rupture before an increase in cardiac troponin T is detectable.

The synergy of honokiol and fluconazole against clinical isolates of azole-resistant Candida albicans

AIMS

To evaluate the interaction of fluconazole (FLC) and honokiol (HNK) in vitro and vivo against azole-resistant (azole-R) clinical isolates of Candida albicans.

METHODS AND RESULTS

A checkerboard microdilution method was used to study the in vitro interaction of FLC and HNK in 24 azole-R clinical isolates of C. albicans. In vivo antifungal activity was performed to further analyse the interaction between FLC and HNK. In the in vitro study, synergism was observed in all 24 FLC-resistant strains tested as determined by fractional inhibitory concentration index (FICI), and in 22 strains by Delta E models. No antagonistic activity was observed in any of the strains tested. These positive interactions were also confirmed by using the time-killing test for the selected strain C. albicans YL371, which shows strong susceptible to the combination of HNK and FLC. In the in vivo study, the mice with candidiasis were treated successfully by a combination therapy of HNK with FLC, the results showed a decrease of the colony forming unit in infected and treated animals compared to the controls, at the conditions of the treatment used in this study.

CONCLUSIONS

Synergistic activity of HNK and FLC against clinical isolates of FLC-resistant C. albicans was observed in vitro and in vivo.

SIGNIFICANCE AND IMPACT OF THE STUDY

This report might provide a potential therapeutic method to overcome the problem of drug-resistance in C. albicans.

Higher moments of net proton multiplicity distributions at RHIC

We report the first measurements of the kurtosis (κ), skewness (S), and variance (σ2) of net-proton multiplicity (Np-Np) distributions at midrapidity for Au+Au collisions at square root of s(NN)=19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (μB) between 200 and 20 MeV. Our measurements of the products κσ2 and Sσ, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the square root of s(NN) dependence of κσ2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for μB below 200 MeV.

Three-particle coincidence of the long range pseudorapidity correlation in high energy nucleus-nucleus collisions

We report the first three-particle coincidence measurement in pseudorapidity (Δη) between a high transverse momentum (p⊥) trigger particle and two lower p⊥ associated particles within azimuth |Δϕ|<0.7 in square root of s(NN)=200 GeV d+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range Δη correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured Δη. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

Establishment and evaluation of a model of a community health service in an underdeveloped area of China

OBJECTIVES

To develop and evaluate an applicable model for a community health service (CHS) in an underdeveloped area of China that ensures efficient, convenient and affordable primary healthcare access for all residents.

STUDY DESIGN

The current study was carried out in Puyang, a typical medium-sized city in central-eastern China. Based on the healthcare requirements of the residents in Puyang, a CHS network was set up and its operation was evaluated from 1999 to 2006. The system is characterized by its focus on community health education (CHE).

METHODS

Firstly, 8231 residents, selected at random, were surveyed to investigate the healthcare requirements of the local residents. Meanwhile, the operation of the pre-existing healthcare resources was investigated in Puyang. Based on the information gained, a network-based CHS system was proposed and established, with CHE as the major focus. This study compared CHS operation prior to and after establishment of the network. Finally, an analytic hierarchy process based evaluation model was applied to evaluate the operation of the CHS network.

RESULTS

There was a high prevalence (86.98 per thousand) of chronic diseases among the residents who participated in this investigation. The majority (84.39%) of the residents who had healthcare requirements resorted to professional health care; the other residents did not have access to health services. Among those residents who sought professional treatment, 71.3% visited primary healthcare institutions. This information reflects the enormous requirement for a CHS in primary health care but the lack of accessibility among the residents; this motivated the authors to establish a system to solve the problem. The improvement in CHS operation after the network was established suggests the importance of a network for optimizing the primary healthcare system. The improvement was indicated by better understanding of the residents regarding the CHS, and enhanced capability of self-monitoring for chronic diseases such as hypertension after the network was established. Moreover, the residents' knowledge of health care was significantly increased and, accordingly, the incidence of health risk behaviour was reduced after the network was established. Furthermore, the CHE index between 1999 and 2006 showed good correlation (r=0.988, p<0.005) with the CHS index, suggesting the important role of CHE in CHS development.

CONCLUSIONS

A network-characterized CHS system was established in Puyang, and improved the primary healthcare situation. This study provides a feasible model for the development of a CHS in medium and small cities in underdeveloped parts of China.

Establishment and biological characterization of fibroblast cell line from the Langshan chicken

OBJECTIVE

We needed to establish an embryonic fibroblast cell line from the Langshan chicken (LSCEF61) to preserve their important genetic resources at the cellular level.

MATERIAL AND METHODS

The cell line was established from 9-day-old embryos by direct explant culture and cryopreservation techniques. Cell morphology, dynamic proliferation and any contamination present were tested, and the karyotype and levels of isoenzymes of lactic dehydrogenase and malic dehydrogenase were analysed. Four types of fluorescent protein exogenous genes for pEGFP-C(1), pEGFP-N(3), pEYFP-N(1) and pDsRed1-N(1) were transfected into the cells.

RESULTS

Showed that the cells were healthy and were of spindle shaped structure, without change in morphology. Cell growth curves were of typical S-shape. Assays for microbial contamination were negative. The LSCEF61 line showed no cross-contamination when assessed by isoenzyme analysis. Chromosome number (2n) = 78 on more than 90% of occasions. The four types of fluorescent protein extro-genes appeared to be expressed effectively with high transfection efficiency between 15.6% and 38.6%.

CONCLUSION

The cell line met each of the quality control standards required for the American Type Culture Collection. It had not only preserved the genetic resources of the important Langshan chicken at the cellular level, but also provided valuable material for genomic, post-genomic and somatic cell cloning research and other applications.

Search for Randall-Sundrum gravitons in the dielectron and diphoton final states with 5.4 fb(-1) of data from pp collisions at square root(s) = 1.96 TeV

Using 5.4  fb(-1) of integrated luminosity from pp collisions at square root(s)=1.96  TeV collected by the D0 detector at the Fermilab Tevatron Collider, we search for decays of the lightest Kaluza-Klein mode of the graviton in the Randall-Sundrum model to ee and γγ. We set 95% C.L. lower limits on the mass of the lightest graviton between 560 and 1050 GeV for values of the coupling k/M(Pl) between 0.01 and 0.1.

Analyzing endodontic infections by deep coverage pyrosequencing

Bacterial diversity in endodontic infections has not been sufficiently studied. The use of modern pyrosequencing technology should allow for more comprehensive analysis than traditional Sanger sequencing. This study investigated bacterial diversity in endodontic infections through taxonomic classification based on 16S rRNA gene sequences generated by 454 GS-FLX pyrosequencing and conventional Sanger capillary sequencing technologies. Sequencings were performed on 7 specimens from endodontic infections. On average, 47 vs. 28,590 sequences were obtained per sample for Sanger sequencing vs. pyrosequencing, representing a 600-fold difference in "depth-of-coverage". Based on Ribosomal Database Project (RDP II) Classifier analysis, pyrosequencing identified 179 bacterial genera in 13 phyla, which was significantly more than Sanger sequencing. The phylum Bacteroidetes was the most prevalent bacterial phylum. These results indicate that bacterial communities in endodontic infections are more diverse than previously demonstrated. In addition, deep-coverage pyrosequencing of the 16S rRNA gene revealed low-abundance micro-organisms with potential clinical implications.

Molecular cloning of the duck MyoG and MRF4 genes coding region sequence and their differential expression patterns in the breast and leg muscle during fetal development

The MyoG and MRF4 genes encode for transcription factors that play key roles in muscle formation during embryonic and fetal development. Due to the unique functions of these two genes, they have a specific expression pattern in the same muscle tissues. In order to investigate the different developmental expression patterns of the two genes, the coding region sequences of duck MyoG and MRF4 were cloned and their mRNA expression patterns in the duck breast and leg muscles were measured using real-time quantitative polymerase chain reaction (qPCR). The duck MyoG and MRF4 both have a basic helix-loop-helix (bHLH) domain with high homology to several other species. In addition, there is a low homology region at the carboxy-terminus of these two proteins. The mRNA expression of MyoG reaches a peak at embryonic day 14 (E14d) in both the breast muscle and the leg muscle of duck. The peak mRNA expression of MRF4 appears at E14d in the breast muscle and at E18d in the leg muscle. The expression patterns of MyoG and MRF4 were different between the breast muscle and the leg muscle of duck. In the fetal duck, the leg muscle develops earlier than the breast muscle, which may better accommodate the newborn duck to a new environment postnatally.Key words: Duck, MyoG and MRF4, expression pattern, fetal development

Prevalence, pattern and determinants of radiographic hand osteoarthritis in five Russian community-based samples

OBJECTIVE

The aim of the study was to evaluate the prevalence and pattern of radiographic hand osteoarthritis (OA) and its association with age, sex, body mass index (BMI), and place of residence in five Russian community-based samples.

DESIGN

Cross-sectional observational study: The study population comprised ethnic Russians [821 males and 1076 females, aged 18-90 (mean 46.2+/-15.3)], living in five different geographic areas. OA was evaluated for 14 joints of the left hand according to the Kellgren and Lawrence grading scheme. Statistical analyses included prevalence estimation, logistic and generalized model regressions, and chi(2) tests.

RESULTS

We present extensive data on the prevalence of radiographic hand OA in a total Russian sample. After the age of 65, 98.5% of males and 96.8% of females had at least one affected joint. In individuals younger than 50, OA was most prevalent in the metacarpophalangeal joints, and after age 50, was most prevalent in the distal interphalangeal joints. Prevalence of hand OA was significantly higher in males than in females in ages 35-50. After adjustment for age, age(2) and place of residence, there were no associations between prevalence or severity of hand OA and BMI.

CONCLUSIONS

Significant differences in prevalence and severity of hand OA were found between the Russian samples living in different geographic areas. Additional studies are needed to discover the mechanism defining the association between places of residence and development of hand OA.

Urodynamic Study of Bladder Function for Patients with Lumbar Spinal Stenosis Treated by Surgical Decompression

Lumbar spinal stenosis usually leads to different degrees of nerve damage, presenting with back and leg pain, and/or neurogenic bladder symptoms. To determine whether lumbar decompression improved urological function, bladder dysfunction was evaluated in this retrospective study of 26 patients with lumbar spinal stenosis who had undergone lumbar decompression surgery. Urodynamic study procedures were performed pre-operatively and 6 months post-operatively. The Japanese Orthopaedic Association score rating system and Oswestry Disability Index were employed for clinical evaluation. Following surgery, post-voiding residual urine, maximum cystometric capacity and maximum flow rate improved significantly. There was no statistically significant improvement in voided volume, bladder compliance, maximum detrusor pressure or upper urinary tract damage. Urodynamic study was important in the diagnosis of neurogenic bladder dysfunction, prevention of renal deterioration and assessment of post-operative effects after surgical decompression for patients with lumbar spinal stenosis.