Independent measurement of the total active 8B solar neutrino flux using an array of 3He proportional counters at the Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.

A nonlinear mixed-effect mixture model for functional mapping of dynamic traits

Functional mapping has emerged as a next-generation statistical tool for mapping quantitative trait loci (QTL) that affect complex dynamic traits. In this article, we incorporated the idea of nonlinear mixed-effect (NLME) models into the mixture-based framework of functional mapping, aimed to generalize the spectrum of applications for functional mapping. NLME-based functional mapping, implemented with the linearization algorithm based on the first-order Taylor expansion, can provide reasonable estimates of QTL genotypic-specific curve parameters (fixed effect) and the between-individual variation of these parameters (random effect). Results from simulation studies suggest that the NLME-based model is more general than traditional functional mapping. The new model can be useful for the identification of the ontogenetic patterns of QTL genetic effects during time course.

Molecular characterization of drug-resistant mycobacterium tuberculosis isolates from Sichuan Province in china

Tuberculosis is still a severe public health issue in eastern Asia, and Sichuan is the key area for tuberculosis control in China. To determine the phenotypic and mutation patterns of drug resistance in Mycobacterium tuberculosis isolates from Sichuan, the drug susceptibility of 198 clinical isolates was examined. Among these isolates, 76 drug-resistant and 20 susceptible isolates were analyzed for the rpoB, embB, and katG and inhA regulatory regions. These are mutations believed to associate with rifampin (RIF), ethambutol (EMB), and isoniazid (INH) resistance, respectively. Of the 60 RIF-resistant isolates, 54 (90.0%) carried mutations on the amplified fragment of the rpoB gene, and the most common one (64.8%, 35/54) was at codon 531. Two new mutation patterns were recognized: one isolate harbored three mutations at codons 511, 516, and 518, and the other carried the dual mutation GAChACC at codon 516. A total of 30 INH-resistant isolates (60.0%, 30/50) had mutations at codon 315, whereas 4 (8.0%) had mutations at the inhA regulatory region. Among the 46 EMB-resistant isolates, 22 harbored the Met306 mutation. The results showed geographical variation in the mutation types of drug-resistant genes in M. tuberculosis isolates from Sichuan; this finding is valuable for the development of targeted and rapid molecular diagnostic methods suitable for specific regions.

Second-trimester fetal growth and the risk of poor obstetric and neonatal outcomes

OBJECTIVE

To compare outcomes of fetuses with an estimated fetal weight (EFW) < 25(th) percentile in the second trimester to those in fetuses with EFW >or= 25(th) percentile in the second trimester.

METHODS

We compared outcomes of 252 pregnancies with an EFW < 25(th) percentile at 18-24 weeks' gestation with those of 265 controls. All pregnancies had early dating by ultrasonography. We excluded fetuses with aneuploidy, major malformations, second-trimester rupture of membranes, and multiple pregnancies.

RESULTS

Second-trimester EFW < 25(th) percentile was significantly associated with higher rates of fetal or neonatal death, third-trimester small for gestational age (SGA), Doppler abnormalities, indicated preterm birth, gestational hypertension or pre-eclampsia before labor, lower birth weight, birth weight < 10(th) percentile, birth weight < 5(th) percentile, and admission to the neonatal intensive care unit. Many of these associations remained even after excluding patients with oligohydramnios, fetal echogenic bowel, and growth asymmetry.

CONCLUSION

Second-trimester SGA, as defined by an EFW < 25(th) percentile using current growth curves, is associated with poor obstetric and neonatal outcomes. Increased surveillance of such pregnancies may be necessary.

Pharmacokinetic characterization of hydroxylpropyl-beta-cyclodextrin-included complex of cryptotanshinone, an investigational cardiovascular drug purified from Danshen (Salvia miltiorrhiza)

1. The study aimed to investigate the pharmacokinetics of cryptotanshinone in a hydroxylpropyl-beta-cyclodextrin-included complex in dogs and rats. 2. Animals were administrated the inclusion complex of cryptotanshinone and the concentrations of cryptotanshinone and its major metabolite tanshinone IIA were determined by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. 3. Cryptotanshinone in inclusion complex was absorbed slowly after an oral dose, and the C(max) and AUC(0-)(t) were dose-proportional. The bioavailability of cryptotanshinone in rats was (6.9% +/- 1.9%) at 60 mg kg(-1) and (11.1% +/- 1.8%) in dogs at 53.4 mg kg(-1). The t(1/2) of the compound in rats and dogs was 5.3-7.4 and 6.0-10.0 h, respectively. Cryptotanshinone showed a high accumulation in the intestine, lung and liver after oral administration, while the lung, liver and heart had the highest level following intravenous dose. Excretion data in rats showed that cryptotanshinone and its metabolites were mainly eliminated from faeces and bile, and the dose recovery rate was 0.02, 2.2, and 14.9% in urine, bile, and faeces, respectively. 4. The disposition of cryptotanshinone in an inclusion complex was dose-independent and the bioavailability was increased compared with that without cyclodextrin used to formulate the drug. Cryptotanshinone was distributed extensively into different organs. Excretion of cryptotanshinone and its metabolites into urine was extremely low, and they were mainly excreted into faeces and bile.

Preclinical factors affecting the pharmacokinetic behaviour of tanshinone IIA, an investigational new drug isolated from Salvia miltiorrhiza for the treatment of ischaemic heart diseases

Tanshinone IIA (TSIIA) is a major active triterpenoid isolated from Salvia miltiorrhiza. The purposes of this study were to investigate various preclinical factors that determined the pharmacokinetics of TSIIA. After oral dosing at 6.7, 20, and 60 mg kg(-1), TSIIA was detected mainly as glucuronidated conjugate (TSIIAG) with only small amounts of the unchanged in the plasma. TSIIA was predominantly excreted into the bile and faeces as TSIIAG, and urine to a minor extent. The C(max) and AUC(0-)(t) of TSIIAG after i.p. administration were significantly lower than those after intragastric administration. The plasma concentration-time profiles of TSIIA following oral dosing of TSIIA showed multiple peaks. The C(max) and AUC(0-)(t) of TSIIA and its glucuronides in rats with intact bile duct were significantly lower than those of rats with bile duct cannulation. Studies from the linked-rat model and intraduodenal injection of bile containing TSIIA and its metabolites indicate that TSIIA glucuronides underwent hydrolysis and the aglycone was reabsorbed from the gut and excreted into the bile as conjugates. TSIIA had a wide tissue distribution, with a very high accumulation in the lung, but very limited penetration into the brain and testes. TSIIA was metabolized by rat CYP2C, 3A and 2D, as ticlopidine, ketoconazole and quinidine all inhibited TSIIA metabolism in rat liver microsomes. Taken collectively, these findings indicate that multiple factors play important roles in determining the pharmacokinetics of TSIIA.

Systemic hemodynamic and regional blood flow changes in response to chronic reductions in uterine perfusion pressure in pregnant rats

Preeclampsia (PE) is associated with increased total peripheral resistance (TPR), reduced cardiac output (CO), and diminished uterine and placental blood flow. We have developed an animal model that employs chronic reductions in uterine perfusion pressure (RUPP) in pregnant rats to generate a “preeclamptic-like” state during late gestation that is characterized by hypertension, proteinuria, and endothelial dysfunction. Although this animal model has many characteristics of human PE, the systemic hemodynamic and regional changes in blood flow that occur in response to chronic RUPP remains unknown. Therefore, we hypothesized that RUPP would decrease uteroplacental blood flow and CO, and increase TPR. Mean arterial pressure (MAP), CO, cardiac index (CI), TPR, and regional blood flow to various tissues were measured using radiolabeled microspheres in the following two groups of conscious rats: normal pregnant rats (NP; n = 8) and RUPP rats ( n = 8). MAP was increased (132 ± 4 vs. 99 ± 3 mmHg) in the RUPP rats compared with the NP dams. The hypertension in RUPP rats was associated with increased TPR (2.15 ± 0.02 vs. 0.98 ± 0.08 mmHg·ml−1·min−1) and decreased CI (246 ± 20 vs. 348 ± 19 ml·min−1·kg−1, P < 0.002) when contrasted with NP dams. Furthermore, uterine (0.16 ± 0.03 vs. 0.38 ± 0.09 ml·min−1·g tissue−1 ) and placental blood flow (0.30 ± 0.08 vs. 0.70 ± 0.10 ml·min−1·g tissue−1) were decreased in RUPP compared with the NP dams. These data demonstrate that the RUPP model of pregnancy-induced hypertension has systemic hemodynamic and regional blood flow alterations that are strikingly similar to those observed in women with PE.

Retrospective analysis of phosphorylation status of the estrogen receptor in patients with early stage disease

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Background: The AKT kinase, when phosphorylated to its activated form (pAKT), mediates many proliferative and survival effects of growth factor receptors such as members of the epidermal growth factor receptor (EGFR) family. Overexpression of AKT in breast neoplasms suggests that AKT activation is involved in breast cancer development and/or progression, and contributes to poor outcome. pAKT is frequently upregulated in Her-2/neu positive breast cancers. Activated AKT is able to phosphorylate in vitro serine 167 (pS167) of estrogen receptor alpha (ERa), resulting in ER-mediated transcriptional activity in the absence of estrogen and possibly contributing to tamoxifen resistance in ERa positive breast cancers. In addition, ERa is phosphorylated at S118 (pS118) by MAPK. Thus, it is possible that pAKT- mediated ERa phosphorylation is implicated in tumorigenesis and resistance to treatment with hormonal therapy in patients with breast cancer. Methods: Utilizing commercially available antibodies, IHC analysis of 125 paraffin-embedded, ERa positive, early breast cancer cases, stratified for stage, were tested for pAKT, PTEN, pS167, and pS118. Staining intensity and number of positive cells were assessed by 4 independent graders. Fisher's exact test was used to determine the significance of associations with a two-sided type I error of 5%. Results: Phosphorylation of AKT occurred in approximately one-half of cases. pS167 was phosphorylated in 66% of pAKT positive cases compared to 35% of pAKT negative cases (p<0.0001). When we analyzed nuclear pAKT staining, this association was more pronounced: 76% of pAKT(+) vs. 37% of pAKT(-) (p<0.0001). 69% of pS118(+) cases were pS167(+) compared to only 15% pS167(+) when pS118 was negative (p<0.0001). In approx. 32% of cases pAKT was present in both the cytoplasm and nucleus. 20% of samples had only cytoplasmic pAKT, while in 4% of cases pAKT was nuclear only, supporting the hypothesis that cytoplasmic phosphorylation of AKT may precede nuclear accumulation. Conclusions: Phosphorylation of pS167ERa is significantly associated with AKT activation (especially in the nucleus) in early breast cancer, supporting the hypothesis that these two events may be causally linked and contribute to breast cancer pathogenesis.

No significant financial relationships to disclose.

Mast cell deficient W/Wv mice have lower serum IL-6 and less cardiac tissue necrosis than their normal littermates following myocardial ischemia-reperfusion

Myocardial ischemia-reperfusion (IR) injury complicates all forms of coronary artery revascularization. Circulating interleukin-6 (IL-6) has been implicated in cell death following a variety of stimuli. Macrophages, platelets, neutrophils and the endothelium have been shown to release IL-6 after IR injury. Cardiac mast cells have been implicated in IR; however, their involvement has never been quantified. In this randomized, prospective study, we compared cardiac tissue susceptibility and serum IL-6 changes between mast cell deficient (W/Wv) mice and their normal littermates (+/+). Twenty-eight male W/Wv mice (n=14) and their +/+ littermates (n=14) were anaesthetized with 2.5% isoflurane. The left coronary artery (LCA) was ligated for 30 minutes or a sham procedure was performed. After 6 hours of reperfusion, the animals were sacrificed. The muscle viability was assessed on fresh whole-mount slices by nitroblue tetrazolium (NBT) histochemical assay and serum IL-6 concentrations measured by ELISA. Cardiac muscle viability was significantly higher in W/Wv mice than the +/+ mice. Serum IL-6 levels were higher in the +/+ sham mice (465 +/- 32 pg/ml, n=6) than the W/Wv mice (185 +/- 31 pg/ml, n=6), p < 0.001. The IL-6 levels increased significantly after reperfusion only in the +/+ mice (698 +/- 41 pg/ml, n=8, p = 0.001), while it remained similar in the W/Wv mice (202 +/- 48 pg/ml, n=8, p = 0.783). These results show that the absence of mast cells reduces the myocardial damage associated with IR injury. Furthermore, there is an attenuation in the inflammatory response, as measured by serum IL-6 levels, following this local insult. This finding entertains the prospect of developing prophylactic therapy--targeting selective inhibition of cardiac mast cell activation, in clinical situations involving medical or surgical myocardial revascularization.

Does the urokinase receptor exist in a latent form?

Multiple cellular functions of urokinase and its receptor are associated with the receptor's capability to interact with a number of ligands at the molecular level. The presence of urokinase is generally needed for the urokinase receptor to acquire this capability. Recent X-ray studies of the structure of the urokinase receptor in complex with either its ligand or peptide inhibitors demonstrate the flexibility of the domain organization of the receptor, suggesting that unliganded urokinase receptor may exist in a latent form that has a conformation different from its ligand-binding form.

Mitochondrial inner membrane electrophysiology assessed by rhodamine-123 transport and fluorescence

Rhodamine-123 is widely used to make dynamic measurements of mitochondrial membrane potential both in vitro and in situ. Yet data interpretation is difficult due to a lack of quantitative understanding of how membrane potential and measured fluorescence are related. To develop such understanding, a model for dye transport across the mitochondrial inner membrane and partition into the membrane was developed. The model accounts for experimentally measured dye self-quenching and was integrated into a model of mitochondrial electrophysiology to estimate transients in mitochondrial membrane potential from kinetic fluorescence measurements. Our analysis indicates that (i) R123 fluorescence peaks at concentrations near 50 microM due to self-quenching; (ii) measured fluorescence intensity and membrane potential are related by a non-linear calibration curve sensitive to certain experimental details, including total concentration of dye and mitochondria in suspensions; and (iii) the time courses of membrane potential and electron transport fluxes following a perturbation (i.e. addition of ADP) significantly differ from observed transients in fluorescence intensity. These findings are consistent with the model predictions that mitochondria display a characteristic time of response to changes in substrate concentration of less than 0.1 s, corresponding to the time scale over which the rate of ATP synthesis changes to meet changes in ADP concentration.

Creep induced rate effects on radial cracks in multilayered structures

This paper considers foundation and epoxy creep induced loading rate effects on radial cracks in multilayered structures. These include top layers of glass or silicon that are bonded to polycarbonate foundations with epoxy. The creep properties of the epoxy join and the polycarbonate foundation are determined using compression experiments and spring-dashpot models. The measured creep parameters are then incorporated into an analytical mechanics model, and finite element simulations are used to predict the effects of creep on the critical loads for radial cracking at different loading rates. The models suggest that the combined effects of creep and slow crack growth must be considered in the predictions of the critical loads required for radial cracking in the systems containing glass top layers. Since slow crack growth does not occur in silicon, the model considering the creep effect is used to predict the critical loads for radial cracking in the systems containing silicon top layers. In both of the structures, analytical solutions are obtained for bi-layer structures and finite element simulations are used for tri-layer structures. Our results show that the analytical solutions obtained by bi-layer structures provide good estimations for tri-layer structures when the epoxy thickness is less than 100 mum. The predictions obtained for both systems are shown to provide improved predictions by comparing with experimental results reported by Lee et al. [J. Am. Ceram. Soc., 2002, 85(8), 2019-2024]. In both systems, the modeling of join/substrate creep is shown to be important for the accurate prediction of loading rate effects on radial cracking.

Bioinspired design of dental multilayers

This paper considers the use of bioinspired functionally graded structures in the design of dental multi-layers that are more resistant to sub-surface crack nucleation. Unlike existing dental crown restorations that give rise to high stress concentration, the functionally graded layers (between crown materials and the joins that attach them to dentin) are shown to promote significant reductions in stress and improvements in the critical crack size. Special inspiration is drawn from the low stress concentrations associated with the graded distributions in the dentin-enamel-junction (DEJ). The implications of such functionally graded structures are also discussed for the design of dental restorations.

Substrate creep on the fatigue life of a model dental multilayer structure

In this article, we investigated the effects of substrate creep on the fatigue life of a model dental multilayer structure, in which a top glass layer was bonded to a polycarbonate substrate through a dental adhesive. The top glass layers were ground using 120 or 600 grit sand papers before bonding to create different subsurface crack sizes and morphologies. The multilayer structures were tested under cyclic Hertzian contact loading to study crack growth and obtain fatigue life curves. The experiment results showed that the fatigue lives of the multilayer structures were impaired by increasing crack sizes in the subsurfaces. They were also significantly reduced by the substrate creep when tested at relatively low load levels, i.e. P(m) < 60 N (P(m) is the maximum magnitude of cyclic load). But at relatively high load levels, i.e. P(m) > 65 N, slow crack growth was the major failure mechanism. A modeling study was then carried out to explore the possible failure mechanisms over a range of load levels. It is found that fatigue life at relatively low load levels can be better estimated by considering the substrate creep effect.