Simulation of the nutrient supply in fracture healing

The healing process for bone fractures is sensitive to mechanical stability and blood supply at the fracture site. Most currently available mechanobiological algorithms of bone healing are based solely on mechanical stimuli, while the explicit analysis of revascularization and its influences on the healing process have not been thoroughly investigated in the literature. In this paper, revascularization was described by two separate processes: angiogenesis and nutrition supply. The mathematical models for angiogenesis and nutrition supply have been proposed and integrated into an existing fuzzy algorithm of fracture healing. The computational algorithm of fracture healing, consisting of stress analysis, analyses of angiogenesis and nutrient supply, and tissue differentiation, has been tested on and compared with animal experimental results published previously. The simulation results showed that, for a small and medium-sized fracture gap, the nutrient supply is sufficient for bone healing, for a large fracture gap, non-union may be induced either by deficient nutrient supply or inadequate mechanical conditions. The comparisons with experimental results demonstrated that the improved computational algorithm is able to simulate a broad spectrum of fracture healing cases and to predict and explain delayed unions and non-union induced by large gap sizes and different mechanical conditions. The new algorithm will allow the simulation of more realistic clinical fracture healing cases with various fracture gaps and geometries and may be helpful to optimise implants and methods for fracture fixation.

Differences in conformational dynamics of [Pt3(HPTAB)]6+-DNA adducts with various cross-linking modes

We present here molecular dynamics simulations and DNA conformational dynamics for a series of trinuclear platinum [Pt₃(HPTAB)]⁶⁺-DNA adducts [HPTAB = N,N,N′,N′,N′′,N′′-hexakis (2-pyridyl-methyl)-1,3,5-tris(aminomethyl) benzene], including three types of bifunctional crosslinks and four types of trifunctional crosslinks. Our simulation results reveal that binding of the trinuclear platinum compound to a DNA duplex induces the duplex unwinding in the vicinity of the platination sites, and causes the DNA to bend toward the major groove. As a consequence, this produces a DNA molecule whose minor groove is more widened and shallow compared to that of an undamaged bare-DNA molecule. Notably, for trifunctional crosslinks, we have observed extensive DNA conformational distortions, which is rarely seen for normal platinum–DNA adducts. Our findings, in this study, thus provide further support for the idea that platinum compounds with trifunctional intra-strand or long-range-inter-strand cross-linking modes can generate larger DNA conformational distortions than other types of cross-linking modes.

As(V) adsorption on maghemite nanoparticles

In this study a novel adsorbent, maghemite nanoparticles (gamma-Fe(2)O(3)), is used for As(V) removal. Maghemite nanoparticles are an exceptional adsorbent material due to its magnetic properties and a good adsorption capacity. The aims of the study were to investigate the suitability of maghemite nanoparticles for As(V) adsorption and to compare properties of different maghemites and their As(V) adsorption efficiency. Maghemite nanoparticles were characterized by XRD, XPS, TEM, VSM, BET and Zeta potential analyzers. Size of the particles varied from 3.8 to 18.4 nm. Adsorption experiments were carried out with three different kinds of maghemite nanoparticles: (i) commercially available, (ii) homemade with mechanochemical method and (iii) homemade with sol-gel process. All three different kinds of maghemite nanoparticles were successful in removing As(V) from water, one of them reached as high adsorption capacity as 50mg/g.

Farm work-related injury among middle school students in rural China

Farm work-related injuries are considered an important issue facing rural area adolescents. However, little research has been done in developing countries, including China. This study evaluated agricultural work-related injuries among Chinese middle school adolescents, focusing on the potential association between farm work hours, sleep patterns, school-related stress, and farm work-related injuries. This cross-sectional study surveyed 1,551 middle school students in Hunan Province who reported working on farms. The surveys assessed their involvement in farm work, sleep patterns, school activities, and farm work-related injuries during a three-month recall period. The cumulative incidence of farm work-related injury was 15.6% among the 1187 students who reported working on a farm. Average days per month farming, number of pesticide applications per month, sleep disturbances, and school-related stress were significantly associated with farm work-related injuries (p < 0.05). Multivariable logistic regression analysis revealed that after adjusting for possible confounding effects of age, gender, and farm work days per month, sleep disturbance (less than 7 hours of sleep: OR = 2.36, 95% CI = 1.07-5.22; awakening at night and having trouble falling back to sleep: OR = 2.70, 95% CI = 1.36-5.37; having nightmares: OR = 2.24, 95% CI = 1.18-4.24) and school-related stress (difficult homework: OR = 2.45, 95% CI = 1.21-4.99; extra homework assigned often by parents: OR = 3.62, 95% CI = 1.88-6.97; and scolded/chastised by parents for poor school performance: OR = 2.53, 95% CI = 1.75-3.65) were statistically significant risk factors for farm work-related injuries (p < 0.05).

Diabetes, pre-diabetes and associated risks on Minnesota code-indicated major electrocardiogram abnormality among Chinese: a cross-sectional diabetic study in Fujian province, southeast China

The goal of this study was to determine the prevalence of diabetes mellitus (DM), impaired glucose regulation (IGR) and related metabolic disorders (overweight, obesity and hypertension) in a Chinese population (20-74 years old). An additional goal was to investigate the relationship between glucose metabolism and the Minnesota code-indicated major abnormal electrocardiogram (MA-ECG). There were 3960 individuals selected from urban and rural areas of Fujian, China from July 2007 to May 2008 by multistage-stratified sampling. Ultimately, data from 3208 subjects (20-74 years old) were analysed (including physical measurements, blood biochemical analysis, oral glucose tolerance test and 12-lead resting ECG). According to World Health Organization diagnostic criteria, the prevalence rates of DM and IGR were 9.51% (male, 10.08%; female, 9.14%) and 14.40% (male, 14.48%; female, 14.35%) respectively. Newly diagnosed DM was found in 53.44% of the diabetic subjects. Based on the 2000 China census, the age-standardized prevalence rates of DM and IGR were 7.19% (male, 7.74%; female, 6.61%) and 11.96 % (male, 12.35%; female, 11.56%) respectively. The age-standardized prevalence rates of DM and IGR in urban areas (7.74% and 12.97% respectively) were slightly but no significantly higher than in rural areas (6.67%, 10.86%). The prevalence rates of overweight, obesity and hypertension were 25.50%, 3.52% and 28.52% respectively (age- and sex- standardized rates: 23.69%, 3.02 % and 22.45 %). After adjusting for other confounding risk factors, multiple logistic regression analysis showed that DM and impaired glucose tolerance were independent risk factors for MA-ECG. Non-diabetic subjects with increased 30-min plasma glucose (PG) after an oral glucose load had a higher risk of MA-ECG after adjusting for other risk factors, especially in those with normal glucose tolerance but with 30-min PG >or= 7.8 mmol L(-1) (odds ratio = 1.371 [1.055-1.780]). The prevalence rates of DM and IGR as well as other metabolic disorders have increased dramatically in the last decade in China, especially in rural areas, with many undiagnosed cases of DM. Even slightly elevated PG levels may predict early cardiovascular events.

Sulfation of dietary flavonoids by human sulfotransferases

Dietary flavonoids catechin, epicatechin, eriodictyol, and hesperetin were investigated as substrates and inhibitors of human sulfotransferases (hSULTs). Purified recombinant proteins and human intestine cytosol were used as enzyme sources. hSULT1A1 and hSULT1A3 as well as human intestine cytosol can catalyse the sulfation of the investigated flavonoids. Sulfation of catechin, epicatechin, eriodictyol, and hesperetin by recombinant hSULTs showed substrate inhibition at high flavonoid concentrations. Hesperetin and eriodictyol are potent inhibitors of purified hSULT1A1, hSULT1A3, hSULT1E1, and hSULT2A1. Catechin and epicatechin inhibited hSULT1A1 and hSULT1A3, but not hSULT1E1 and hSULT2A1. The sulfation efficacy and potency of inhibition is related to the C-ring structure of flavonoids. These results suggest that dietary flavonoids may regulate human SULT activity and, therefore, affect the regulation of hormones and neurotransmitters, detoxification of drugs, and the bioactivation of pro- carcinogens and pro-mutagens.

Involved-field radiotherapy for patients with limited small cell lung cancer: Patterns of local-regional failure and feasibility

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Background: To investigate the feasibility of the involved-field radiotherapy in patients with limited-stage small cell lung cancer (LSCLC) according to the patterns of local failure, focused on the first local-regional failure. Methods: Two clinical phase II studies for patients with LSCLC treated at our institute between 1997 and 2007 were reviewed. All patients received combined chemotherapy (CHT) with cisplatin and etoposide, and thoracic RT (TRT) was generally delivered sequentially following one to three cycles of CHT and consisted of either 56 Gy in 40 fractions for 4 weeks or 55 Gy in 22 fractions for 4–5 weeks. TRT fields encompassed primary tumor volume (post-CHT) and the involved nodal areas (pre- and post-CHT) without elective node irradiation. The local-regional failure was defined as failure within thoracic cavity and supraclavicular fossa except for pleural effusion, which was then divided into two subtypes: in-field and out-field failure according to the first occurred site in the planning target volume or not. Results: There were 89 patients completed the planed regimen and eligible for evaluating patterns of failure, 54 patients (57%) in 56 Gy cohort and 35 patients(43%) in 55 Gy cohort. The media cycles of CHT were 6 (4–8). The overall survival and local progression-free survival rates for 89 patients at 2 years were 56% and 71%, respectively, with a median survival of 25.6 months. 56 patients (63%) developed distant metastases and 21 patients (24%) developed local-regional failures: 12 in-field and 9 out-field. 8 out of 9 out-field failures occurred in the ipsilateral supraclavicular fossa, and the media duration to the end of TRT was 6 mouths (5–14). Comparing the 56 Gy and 55 Gy cohorts, the rates of any thoracic, in-field and out-field failures were no difference significantly. Conclusions: Thoracic radiotherapy using involved-field technique in patients with LSCLC resulted in a high failure rate of the supraclavicular fossa. Whether improving accuracy for the initial evaluation of clinical stage could reduce out-field failure in supraclavicular fossa need to be investigated.

No significant financial relationships to disclose.

A novel model including CXCR4 and CDK6 as potential predictive marker for docetaxel (doc) sensitivity in gastric cancer (GC)

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Background: A growing body of evidence has shed light on biomarkers for chemotherapeutic agent sensitivity in gastric cancer (GC) treatment. It has been demonstrated β-tubulin Ш (TUBB3) and microtubule associated protein tau (MAPT) might be considered as potential markers for taxanes treatment. However, an integrated predictive model for docetaxel (doc) sensitivity is still needed to customized chemotherapy in gastric cancer. Methods: Doc resistant gastric cancer cell line was established by exposure to gradually increasing doc concentration on an intermittent dosage schedule. Microarray was performed to explore different gene expression levels between parental cells and resistant cells. 11 gastrointestinal cancer cell lines were used to validate gene levels by real-time quantitative PCR as well as doc cytotoxicity. Histoculture drug response assay (HDRA) was adopted to examine doc sensitivity in 25 surgically dissected GC specimens. Discrimination analyses were used to determine which linear combinations of these genes best distinguished responder patients from nonresponder patients by adding one more genes each time. Results: After functional analysis of microarray, a panel of 11 genes were further validated, which resulting 4 genes, CXCR4 (P=0.047), CDK6 (P=0.014), USP15 (P<0.001) and CDH1 (P=0.001) that correlated to the doc sensitivity. The mRNA levels of CXCR4 and CDK6 were significantly higher in resistant GC specimens (P=0.0298, 0.022 respectively). A final response index including 5 genes (CXCR4, CDK6, USP15, TUBB3 and MAPT) showed potential predictive value for doc associated chemotherapy with an accuracy of 84% (P=0.001). Conclusions: A predictive model with five genes for doc therapy was generated and showed novel predictive role in doc sensitivity in GC.

No significant financial relationships to disclose.

A combination of grape seed-derived procyanidins and gypenosides alleviates insulin resistance in mice and HepG2 cells

This study investigated the effects of grape seed-derived procyanidins (GSP), gypenosides (GPE), and combination procyanidins/gypenosides on insulin resistance in mice and HepG2 cells. ICR mice were randomly divided into 2 control and 4 treatment groups. The control mice were to receive either normal diet (ND) or high-fat diet (HFD), and the treatment groups were fed high-fat diet with either 80 mg/kg of GSP (GSP80), GPE (GPE80), GSP + GPE (1: 1, GSP40 + GPE40), or 500 mg/kg of metformin for a 6-wk period. All the groups of mice except the normal control were on high-fat diet along with fructose (15%) administered in drinking water throughout the period of treatment. An insulin-resistant HepG2 cell model was developed after 24 h of 5 x 10(-7) mol/L insulin incubation. The treatment of GPE80 could significantly reduce the index of insulin resistance (HOMA-IR) and increase hepatic glycogen concentration, compared with HFD group (P < 0.05). When GSP and GPE were administered simultaneously, synergic effects were observed in decreasing the HOMA-IR index and serum total cholesterol (TC) level and enhancing glucose tolerance. All treatment groups showed considerable raise of hepatic glucokinase activity (P < 0.05 compared with HFD group). GSP application increased the consumption of extracellular glucose in HepG2 cells. Our data suggest that the combination of GSP and GPE may have functional efficacy in consumers with insulin resistance.

Increased phonon scattering by nanograins and point defects in nanostructured silicon with a low concentration of germanium

The mechanism for phonon scattering by nanostructures and by point defects in nanostructured silicon (Si) and the silicon germanium (Ge) alloy and their thermoelectric properties are investigated. We found that the thermal conductivity is reduced by a factor of 10 in nanostructured Si in comparison with bulk crystalline Si. However, nanosize interfaces are not as effective as point defects in scattering phonons with wavelengths shorter than 1 nm. We further found that a 5 at. % Ge replacing Si is very efficient in scattering phonons shorter than 1 nm, resulting in a further thermal conductivity reduction by a factor of 2, thereby leading to a thermoelectric figure of merit 0.95 for Si95Ge5, similar to that of large grained Si80Ge20 alloys.