A 5-item prediction rule to identify severe renal dysfunction in patients with acute stroke

BACKGROUND AND PURPOSE

Although patients with severe renal dysfunction who receive iodinated contrast are at high risk of CIN, contrast-enhanced CT scans are often obtained without prior knowledge of kidney function in patients with acute stroke. We aimed to develop a tool to identify patients with acute stroke at a high risk of CIN in the absence of a recent GFR.

MATERIALS AND METHODS

We used the RCSN (9872 patients) and OSA (2544 patients) for our derivation and validation cohort, respectively. A multivariable logistic regression model was performed to develop a predictive tool to identify severe renal dysfunction (defined as a GFR < 30 mL/min/1.73 m(2)).

RESULTS

The overall prevalence of severe renal dysfunction was 4.9% and 5.2% in the derivation and validation cohort, respectively. The prediction rule was designed as follows: (age in years) + (5 points for women) + (5 points for history of diabetes mellitus) + (15 points for preadmission insulin use) + (10 points for history of hypertension). The prevalence of severe renal dysfunction is negligible in patients with a total score of ≤70 (≤0.005%-0.7%) but increases with higher Renal Risk Scores (eg, scores 71-80: 2.1%-2.2%; scores 91-100: 6.6%-7.1%; scores 111-120: 15.9%-28.1%).

CONCLUSIONS

The Renal Risk Score is a validated tool that helps clinicians select which patients with stroke can safely proceed to contrast-enhanced brain imaging without waiting for laboratory evidence of good renal function.

Strength analysis and optimisation of double-toroidal anvils for high-pressure research

We used the finite element method for stress and deformation analysis of the large sample volume double-toroidal anvil and gasket assembly used with the Paris-Edinburgh press for neutron scattering, in order to investigate the failure of this assembly observed repeatedly in experiments at a load of approximately 240 tonnes. The analysis is based on a new approach to modelling an opposed anvil device working under extreme stress conditions. The method relies on use of experimental data to validate the simulation in the absence of the material property data available for high pressure conditions. Using this method we analysed the stress distribution on the surface and in the bulk of the double-toroidal anvils, and we conclude that the failure occurs on the surface of the anvil and that it is caused by the tensile stress. We also use the model to show possible ways of optimising the anvil design in order to extend its operational pressure range.

ADAMTS9 is a functional tumor suppressor through inhibiting AKT/mTOR pathway and associated with poor survival in gastric cancer

Using genome-wide promoter methylation analysis, we identified a disintegrin-like and metalloprotease with thrombospondin type 1 motif 9 (ADAMTS9) is methylated in cancer. We aim to clarify its epigenetic inactivation, biological function and clinical implication in gastric cancer. ADAMTS9 was silenced in 6 out of 8 gastric cancer cell lines. The loss of ADAMTS9 expression was regulated by promoter hypermethylation and could be restored by demethylation agent. Ectopic expression of ADAMTS9 in gastric cancer cell lines (AGS, BGC823) inhibited cell growth curve in both the cell lines (P<0.0001), suppressed colony formation (P<0.01) and induced apoptosis (P<0.001 in AGS, P<0.01 in BGC823). Moreover, conditioned culture medium from ADAMTS9-transfected cell lines significantly disrupted the human umbilical vein endothelial cell tube formation capacity on Matrigel (P<0.01 in AGS, P<0.001 in BGC823). The in vivo growth of ADAMTS9 cells in nude mice was also markedly diminished after stable expression of ADAMTS9 (P<0.001). On the other hand, ADAMTS9 knockdown promoted cell proliferation (P<0.001). We further revealed that ADAMTS9 inhibited tumor growth by blocking activation of Akt and its downstream target the mammalian target of rapamycin (mTOR). ADAMTS9 also reduced phosphorylation of mTOR downstream targets p70 ribosomal S6 kinase, eIF4E-binding protein and downregulated hypoxia-inducible factor-1α. Therefore, this is the first demonstration that ADAMTS9 is a critical tumor suppressor of gastric cancer progression at least in part through suppression of oncogenic AKT/mTOR signaling. Moreover, promoter methylation of ADAMTS9 was detected in 29.2% (21/72) of primary gastric tumors. Multivariate analysis showed that patients with ADAMTS9 methylation had a poorer overall survival (relative risk (RR)=2.788; 95% confidence interval, 1.474-5.274; P=0.002). Kaplan-Meier survival curves showed that ADAMTS9 methylation was significantly associated with shortened survival in gastric cancer patients (P=0.001, log-rank test). In conclusion, ADAMTS9 acts as a functional tumor suppressor in gastric cancer through inhibiting oncogenic AKT/mTOR signaling pathway. Methylation of ADAMTS9 is an independent prognostic factor of gastric cancer.

Quantitative assessment of external carotid artery territory supply with modified vessel-encoded arterial spin-labeling

BACKGROUND AND PURPOSE

In patients with carotid stenosis or occlusion, cerebral blood could be supplied through collateral pathways to improve regional blood flow and protect against ischemic events. The contribution of collaterals from the ICA can be assessed by depiction of vascular perfusion territories with ASL. However, so far there is no method available to evaluate the collateral perfusion territory from the ECA in MR imaging. In this study, we present a new labeling scheme based on VE-ASL to quantitatively assess the perfusion territory of the ECA.

MATERIALS AND METHODS

A new labeling approach with a Hadamard encoding scheme was developed to label major arteries, especially the ECA. Twelve healthy subjects with normal cerebrovascular anatomy were examined to demonstrate their perfusion territories. Eight patients with carotid artery stenosis or occlusion were assessed before and after surgery to show changes of their collateral blood supply.

RESULTS

The proposed method enables assessment of the perfusion territories of the ECA. Good agreement was found between the vascular territories and normal cerebrovascular anatomy in healthy subjects. For the patients with carotid stenosis or occlusion, our noninvasive results provided information on collateral flow comparable with that from DSA. Their collateral flows from the ECA, moreover, could be quantitatively estimated pre- and postoperatively.

CONCLUSIONS

The modified approach has been validated by the consistency of collateral perfusion territories with cerebrovascular anatomy, and quantitative assessment of collaterals proved useful for assisting in evaluating therapeutic interventions.

First observation of the M1 transition ψ(3686)→γη(c)(2S)

Using a sample of 106×10(6) ψ(3686) events collected with the BESIII detector at the BEPCII storage ring, we have made the first measurement of the M1 transition between the radially excited charmonium S-wave spin-triplet and the radially excited S-wave spin-singlet states: ψ(3686)→γη(c)(2S). Analyses of the processes ψ(3686)→γη(c)(2S) with η(c)(2S)→K(S)(0)K(±)π(∓) and K(+)K(-)π(0) give an η(c)(2S) signal with a statistical significance of greater than 10 standard deviations under a wide range of assumptions about the signal and background properties. The data are used to obtain measurements of the η(c)(2S) mass (M(η(c)(2S))=3637.6±2.9(stat)±1.6(syst) MeV/c(2)), width (Γ(η(c)(2S))=16.9±6.4(stat)±4.8(syst) MeV), and the product branching-fraction (B(ψ(3686)→γη(c)(2S))×B(η(c)(2S)→KKπ)=(1.30±0.20(stat)±0.30(syst))×10(-5)). Combining our result with a BABAR measurement of B(η(c)(2S)→KKπ), we find the branching fraction of the M1 transition to be B(ψ(3686)→γη(c)(2S))=(6.8±1.1(stat)±4.5(syst))×10(-4).

Cell cycle-dependent dynamics of cytoskeleton involving mitochondrial redistribution in hamster embryos

Mitochondria-cytoskeleton interactions were studied in the hamster embryos during interphase and M phase of the cell cycle. Two-cell embryos were cultured for 1 h with nocodazole, cytochalasin D or in a combination of both inhibitors and then centrifuged at 10,000 × g for 2 min. The control embryos were only centrifuged with no inhibitor treatment. Centrifuged embryos were fluorescently stained to examine the distribution of active mitochondria and nuclear configuration. In the control 2-cell embryos, most mitochondria were accumulated at the perinuclear region with some at the cell cortex. Neither each inhibitor nor centrifugation did affect the distribution of mitochondria in interphase blastomeres. However, mitochondria were spun down towards the centrifugal pole in 71% (n = 41) of the interphase blastomeres treated with centrifugation following a combination of nocodazole plus cytochalasin D, suggesting that both microtubules and microfilaments may involve in mitochondrial redistribution during interphase of the cell cycle. In contrast, when M-phase blastomeres were treated with all drug treatments applied, including cytochalasin D, mitochondria had been usually dislocated in a unipolar cluster, suggesting that microfilaments, not microtubules, may involve in the mitochondrial redistribution during M phase of the cell cycle. The data indicate that microfilaments function in mitochondrial redistribution regardless of the stages of the cell cycle and that microtubules may strongly associate with mitochondria during the interphase but dissociate from them during the M phase.

Measurements of the mass and width of the η(c) using the decay ψ(3686)→γη(c)

The mass and width of the lowest-lying S-wave spin singlet charmonium state, the η(c), are measured using a data sample of 1.06×10(8) ψ(3686) decays collected with the BESIII detector at the BEPCII storage ring. We use a model that incorporates full interference between the signal reaction, ψ(3686)→γη(c), and a nonresonant radiative background to describe the line shape of the η(c) successfully. We measure the η(c) mass to be 2984.3±0.6±0.6 MeV/c(2) and the total width to be 32.0±1.2±1.0 MeV, where the first errors are statistical and the second are systematic.

First observation of η(1405) decays into f(0)(980)π0

The decays J/ψ → γ π+ π- π0 and J/ψ → γ π0 π0 π0 are analyzed using a sample of 225×10(6) J/ψ events collected with the BESIII detector. The decay of η(1405) → f(0)(980)π0 with a large isospin violation is observed for the first time. The width of the f(0)(980) observed in the dipion mass spectra is anomalously narrower than the world average. Decay rates for three-pion decays of the η' are also measured precisely.

Spin-parity analysis of pp¯ mass threshold structure in J/ψ and ψ(3686) radiative decays

A partial wave analysis of the pp¯ mass-threshold enhancement in the reaction J/ψ→γpp¯ is used to determine its J(PC) quantum numbers to be 0(-+), its peak mass to be below threshold at M=1832(-5)(+19)(stat)(-17)(+18)(syst)±19(model) MeV/c(2), and its total width to be Γ<76 MeV/c(2) at the 90% C.L. The product of branching ratios is measured to be BR[J/ψ→γX(pp¯)]BR[X(pp¯)→pp¯]=[9.0(-1.1)(+0.4)(stat)(-5.0)(+1.5)(syst)±2.3(model)]×10(-5). A similar analysis performed on ψ(3686)→γpp¯ decays shows, for the first time, the presence of a corresponding enhancement with a production rate relative to that for J/ψ decays of R=[5.08(-0.45)(+0.71)(stat)(-3.58)(+0.67)(syst)±0.12(model)]%.

Association of sleep duration and hypertension among US adults varies by age and sex

BACKGROUND

While short sleep duration has been related to hypertension, the impact of age and sex on this association is less well known. We examined the association between hours of sleep and hypertension prevalence among US adults by age and sex.

METHODS

The study was conducted using data from the 2007-2009 National Health Interview Surveys (NHISs). The association between self-reported hours of sleep and prevalence of hypertension was assessed after stratifying by age and sex.

RESULTS

Among 71,455 participants, age-standardized hypertension prevalence rates (%) were 32.4, 25.5, 22.2, 23.2, 25.5, and 32.5 among adults reporting sleep of <6, 6, 7, 8, 9, and ≥10 h/day, respectively (P < 0.001). There was a "U"-shaped association of hours of sleep and hypertension prevalence among all age and sex subgroups. Logistic regression models, using 8 h sleep/day as the referent, showed a greater likelihood of hypertension among those who slept <7 or ≥10 h/day after adjusting for sociodemographic, behavior, and health characteristics. Further stratifying by age and sex, while adjusting for all other characteristics, revealed that among adults less than 45 years, short (<6 h for men and <8 h for women) and long (≥10 h for men) sleep were associated with higher likelihood of hypertension. For other age/sex groups, short sleep (<6 h) was associated with higher likelihood of hypertension among middle-aged men and older women, as was long sleep (≥10 h) among middle-aged women.

CONCLUSIONS

This national sample study suggests that the association between hours of sleep and hypertension varies by age and sex.

The effect of age and cerebral ischemia on diffusion-weighted proton MR spectroscopy of the human brain

BACKGROUND AND PURPOSE

DW-MRS is a promising tool for the noninvasive identification of the cellular response to cerebral ischemia. To date, the potential confounding effects of aging and the stage of ischemia are unknown. We, therefore, examined the cross-sectional effects of age and different stages of cerebral ischemia on the diffusion of brain metabolites.

MATERIALS AND METHODS

The ADCs of 3 major metabolites, including Cho, Cr, and NAA were measured by DW-MRS in healthy younger (n = 26, 24 ± 2.2 years of age) and older (n = 17, 63 ± 7.0 years of age) adults, as well as in patients with acute (n = 7, 57 ± 4.0 years of age) and subacute (n = 12, 62 ± 7.8 years of age) cerebral ischemia.

RESULTS

Compared with younger adults, healthy older adults presented with significantly reduced ADC values of NAA (P = .000052), Cr (P = .000018), and Cho (P = .00075). Meanwhile, the ADC values of NAA (F(2,36) = 6.057, P = .006), Cr (F(2,36) = 5.634, P = .008), and Cho (F(2,36) = 8.167, P = .001) were significantly different among the acute cerebral ischemia group, subacute cerebral ischemia group, and healthy older controls. These metabolites decreased in the acute stage of cerebral ischemia but increased in the subacute stage, compared with age-matched controls.

CONCLUSIONS

The effect of age should be considered when analyzing diffusion of cerebral metabolites with DW-MRS. Our observations also suggest that metabolite diffusion data may be used to reveal changes in the intracellular environment, depending on the pathologic status of ischemia.

Assessing the Impact of Thrombolysis on Progress through Inpatient Rehabilitation after Stroke: A Multivariable Approach

Background

Acute administration of tissue plasminogen activator has been shown to improve immediate and long-term patient recovery after ischaemic stroke. Yet, despite widespread clinical application, many patients who receive acute tissue plasminogen activator still require inpatient rehabilitation.

Aims and Hypothesis

This study aimed to examine the effect of tissue plasminogen activator administration on recovery among patients requiring inpatient rehabilitation after stroke in Ontario, Canada. It was hypothesized that after covariate adjustment, administration of tissue plasminogen activator would be associated with accelerated progress through inpatient rehabilitation.

Methods

Acute and rehabilitation data were retrieved from the Registry of the Canadian Stroke Network and the National Rehabilitation Reporting System for all ischaemic stroke patients admitted to an acute facility and a rehabilitation unit between July 1, 2003 and March 31,2008. Patients were divided into two groups: those who received tissue plasminogen activator and those who were medically eligible but did not receive tissue plasminogen activator. Three rehabilitation progress indicators were compared between groups: Functional Independence Measure gain, active length of stay, and discharge destination. Indicators were modelled using multivariable generalized linear models or logistic regression as appropriate.

Results

Patients who received tissue plasminogen activator experienced shorter active lengths of stay (log estimate ± standard error: −0.04 ± 0.01 days), and were slightly more likely to be discharged home compared to controls (adjusted odds ratio 1.35, 95% confidence interval 1.004–1.82). No differences were noted on Functional Independence Measure gain during rehabilitation.

Conclusion

Results suggest that tissue plasminogen activator may contribute to accelerated progress through inpatient rehabilitation; however, there is no evidence to suggest that it contributes to greater functional improvement as measured by the Functional Independence Measure.

ηπ+ π- resonant structure around 1.8 GeV/c(2) and η(1405) in J/ψ → ωηπ+ π-

We present results of a study of the decay J/ψ → ωηπ+ π- using a sample of (225.2 ± 2.8) × 10(6) J/ψ events collected by the BESIII detector, and report the observation of a new process J/ψ → ωX(1870) with a statistical significance of 7.2σ, in which X(1870) decays to a(0)(±)(980)π±. Fitting to ηπ+ π- mass spectrum yields a mass M = 1877.3 ± 6.3(stat)(-7.4)(+3.4)(syst) MeV/c(2), a width Γ = 57 ± 12(stat)(-4)(+19)(syst) MeV/c(2), and a product branching fraction B(J/ψ → ωX) × B(X→a(0)(±)(980)π±) × B(a(0) (±)(980) → ηπ±) = [1.50 ± 0.26(stat)(-0.36)(+0.72) (syst)] × 10(-4). Signals for J/ψ → ωf(1)(1285) and J/ψ → ω η(1405) are also clearly observed and measured.

Kinematic modelling of a robotic gait device for early rehabilitation of walking

Rehabilitation of walking is an essential element in the treatment of incomplete spinal cord injured (SCI) patients. During the early post injury period, patients find it challenging to practice upright walking. Simulating stepping movements in a supine posture may be easier and promote earlier rehabilitation. A robotic orthotic device for early intervention in spinal cord injury that does not require the patient to be in an upright posture has been modelled. The model comprises a two-bar mechanical system that is configured and powered to provide limb kinematics that approximate normal overground walking. The modelling work has been based on gait analysis performed on healthy subjects walking at 50 per cent, 75 per cent, and 100 per cent of normal cadence. Simulated angles of hip, knee, and ankle joints show a comparable range of motion (ROM) to the experimental walking data measured in healthy subjects. The model provides operating parameters for a prospective recumbent gait orthosis that could be used in early walking rehabilitation of incomplete SCI patients.

Observation of χ(c1) decays into vector meson pairs φφ, ωω, and ωφ

Using (106±4)×10⁻⁶ ψ(3686) events accumulated with the BESIII detector at the BEPCII e⁺e⁻ collider, we present the first measurement of decays of χ(c1) to vector meson pairs φφ, ωω, and ωφ. The branching fractions are measured to be (4.4±0.3±0.5)×10⁻⁴, (6.0±0.3±0.7)×10⁻⁴, and (2.2±0.6±0.2)×10⁻⁵, for χ(c1)→φφ, ωω, and ωφ, respectively, which indicates that the hadron helicity selection rule is significantly violated in χ(cJ) decays. In addition, the measurement of χ(cJ)→ωφ provides the first indication of the rate of doubly OZI-suppressed χ(cJ) decay. Finally, we present improved measurements for the branching fractions of χ(c0) and χ(c2) to vector meson pairs.

The impact of the herbicide atrazine on growth and photosynthesis of seagrass, Zostera marina (L.), seedlings

The impact of the widely used herbicide atrazine on seedling growth and photosynthesis of eelgrass was determined. The long-term impact of the herbicide atrazine (1, 10 and 100 μg/L) on growth of eelgrass Zostera marina (L.) seedlings, maintained in outdoor aquaria, was monitored over 4 weeks. Exposure to 10 μg/L atrazine resulted in significantly lower plant fresh weight and total chlorophyll concentration and up to 86.67% mortality at the 100 μg/L concentration. Short-term photosynthetic stress on eelgrass seedlings was determined and compared with adult eelgrass using chlorophyll fluorescence. The effective quantum yield in eelgrass seedlings was significantly depressed at all atrazine concentrations (2, 4, 8, 16, 32 and 64 μg/L) even within 2 h and remained at a lower level than for adult plants for each concentration. These results indicate that atrazine presents a potential threat to seagrass seedling functioning and that the impact is much higher than for adult plants.

Developmental changes in cell proliferation and apoptosis in the normal duck thymus

Cell proliferation and apoptosis in the normal duck thymus during embryonic and post-embryonic development were studied. The flow cytometry assay shows that the level of G(0)/G(1) thymic cell population and the proportion of apoptotic cells increased with age, while the levels of S phase, G(2) + M phase and the proliferating index decreased with age. Proliferation cell nuclear antigen (PCNA) was mainly detected in the nuclei of lymphocytes. The number of PCNA-positive cells in the cortex and medulla significantly decreased with age. Transferase-mediated dUTP nick-end labelling (TUNEL) reaction stained apoptotic bodies in the cytoplasm of macrophages and free apoptotic bodies or nuclei with condensed chromatin in lymphocytes. The number of TUNEL-positive cells in the cortex and medulla markedly increased with age. The amount of proliferation and apoptotic cells in the thymic cortex was higher than that in the medulla. The balance between proliferation and apoptosis in the duck thymus may account for the process of thymic development and involution.

Causes of death among people with convulsive epilepsy in rural West China: a prospective study

BACKGROUND

Epilepsy is a serious health problem associated with an increased risk of premature mortality. Few studies have investigated risk factors for this. Understanding these risks may enable the implementation of preventative measures to reduce premature mortality.

METHODS

A management program for convulsive forms of epilepsy has been in place at the primary health care level in rural West China since May 2005. Demographic data and putative causes of death of attendees of the program since inception to the end of December 2009 have been recorded. Case fatality (CF), the proportional mortality ratios (PMRs) for each cause, and standardized mortality ratios (SMRs) for each age and cause were estimated based on the 2007 Chinese rural population.

RESULTS

There were 106 reported deaths (70 male) among 3,568 people. CF was 2.97% during a median of 28 months' follow-up. The highest PMRs were for accidental death (59%) including drowning (45.1%); probable sudden unexpected death in epilepsy (SUDEP) (14.7%); status epilepticus (6.9%), and neoplasm (6.9%). The overall SMR was 4.92 (95% confidence interval 4.0-6.1); the risks were high in young people. The risk of drowning was 82-fold higher in the cohort than the general population.

CONCLUSION

In rural West China, the risk of premature death is nearly 5 times higher in people with convulsive epilepsy than in the general Chinese population and especially high among young people. Accidental death, including drowning, and probable SUDEP are the leading putative causes of death in people with convulsive epilepsy in rural West China.