The role of reactive oxygen species and autophagy in safingol-induced cell death

Safingol is a sphingolipid with promising anticancer potential, which is currently in phase I clinical trial. Yet, the underlying mechanisms of its action remain largely unknown. We reported here that safingol-induced primarily accidental necrotic cell death in MDA-MB-231 and HT-29 cells, as shown by the increase in the percentage of cells stained positive for 7-aminoactinomycin D, collapse of mitochondria membrane potential and depletion of intracellular ATP. Importantly, safingol treatment produced time- and concentration-dependent reactive oxygen species (ROS) generation. Autophagy was triggered following safingol treatment, as reflected by the formation of autophagosomes, acidic vacuoles, increased light chain 3-II and Atg biomarkers expression. Interestingly, scavenging ROS with N-acetyl-L-cysteine could prevent the autophagic features and reverse safingol-induced necrosis. Our data also suggested that autophagy was a cell repair mechanism, as suppression of autophagy by 3-methyladenine or bafilomycin A1 significantly augmented cell death on 2-5 μM safingol treatment. In addition, Bcl-xL and Bax might be involved in the regulation of safingol-induced autophagy. Finally, glucose uptake was shown to be inhibited by safingol treatment, which was associated with an increase in p-AMPK expression. Taken together, our data suggested that ROS was the mediator of safingol-induced cancer cell death, and autophagy is likely to be a mechanism triggered to repair damages from ROS generation on safingol treatment.

Arterial stiffness and asymptomatic intracranial large arterial stenosis and calcification in hypertensive chinese

BACKGROUND

Intracranial large artery disease (ICLAD), such as stenosis and calcification, is common in Chinese patients with stroke. However, little is known about ICLAD and its association with large arterial stiffness in hypertensive patients.

METHODS

We recruited 270 (mean age 61.0 years, 45.6% male) untreated hypertensive patients without stroke from a community in Shanghai, China. ICLAD was detected by computerized tomographic angiography (CTA). Carotid-femoral pulse wave velocity (cf-PWV), office, and 24-h ambulatory pulse pressure (PP) as well as ambulatory arterial stiffness index (AASI) were determined as the measures of arterial stiffness.

RESULTS

Among all participants, 26 (9.6%) had concurrent intracranial arterial stenosis and calcification, 11 (4.1%) stenosis only, and 71 (26.3%) calcifications only. After adjustment for age, mean arterial pressure, and other covariables, there was significant difference in cf-PWV (13.1 vs. 13.7 vs. 15.0 m/s; P = 0.0015) and 24-h PP (46.7 vs. 48.8 vs. 55.7 mm Hg; P = 0.0007) between patients with normal vessels (n = 162), with stenosis or calcification (n = 82), and with both lesions (n = 26). Multiple ordinal logistic regression analyses showed that both cf-PWV and 24-h PP were independently associated with ICLAD. Odds ratios (95% confidence interval (CI)) of ICLAD after multivariable and mutually adjustment were 1.51 (1.09-2.10) and 1.46 (1.06-2.01) for 1-s.d. increase in cf-PWV and 24-h PP, respectively. No significant association (P ≥ 0.10) with AASI or office PP was observed in multivariable analysis.

CONCLUSION

Increased arterial stiffness was independently associated with ICLAD. cf-PWV and 24-h PP might be useful in identifying those more likely to have ICLAD among hypertensive patients.

Phase I study of at-101 (R-(-)-gossypol) in combination with paclitaxel (P) and carboplatin (C) in solid tumors including castrate-resistant prostate cancer (CRPC)

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Background: The combination of paclitaxel (P) and carboplatin (C) has broad anti-tumor activity in multiple tumor types including prostate and bladder cancer. Overexpression of Bcl-2 is a common mechanism of resistance to cytotoxic chemotherapy. AT-101 is an oral inhibitor of Bcl- 2-family-anti-apoptotic proteins. We conducted a phase I study of the combination of AT-101, P and C.

Methods: Ph I study in pts with refractory solid tumors, ECOG 0-1, using a standard 3+3 design to evaluate safety, tolerability and pharmacokinetics/pharmacodynamics (PK/PD). AT-101 was administered orally on Days 1-3 Q12 hr. P and C were administered intravenously on day 1 every 21 days. Dosing levels (DL) were 1: AT-101 40 mg BID, P 150mg/m2, C AUC 5; and DL 2: AT-101 40 mg BID, P 175/m2, C AUC 6. 12 additional pts treated at the MTD dose level were divided into two groups – with AT-101 omitted in the morning of C1D1 or C2D1 to assess apoptotic markers during P and C chemotherapy with and without AT-101.

Results: 24 pts (CRPC-11, colon-3, breast-3 melanoma-2, penile-1, esophageal adeno-1, thymus adeno-1, bladder neuroendocrine-1, NSCLC-1) with median age of 61.5 were enrolled. 6 pts were treated in DL1, and 18 in DL2 (the MTD). Dose limiting toxicities were G3 abdominal pain (1 pt, DL1) and G3 ALT (1pt, DL2). Common G1/G2 AEs were nausea, vomiting, fatigue, anorexia and neutropenia. 4 pts had dose reductions after cycle 1 due to AEs. 12 pts had GCSF added after C1 due to neutropenia. 4/11 (36%) pts with CRPC (all previously treated with docetaxel) had PSA declines of ≥50% and 4 pts had stable disease from 4 to 14 cycles. 2 pts with CRPC had a PR by RECIST. Additionally, 1 pt with esophageal CA had a CR and 1 pt with NSCLC had a PR. PK analysis demonstrated P PK was not influenced by co- administration of C and AT-101 when compared with historical reports (Siddiqui BJC 1997). The PK of AT-101 was not altered significantly by the P dose levels.

Conclusions: The addition of AT-101 to PC chemotherapy is well tolerated and clinically active in advanced cancer pts. The combination of AT-101 and PC may be appropriate for further study in pts with chemorefractory CRPC.

No significant financial relationships to disclose.

Event-related potential effects of superior action anticipation in professional badminton players

The ability to predict the trajectory of a ball based on the opponent's body kinematics has been shown to be critical to high-performing athletes in many sports. However, little is known about the neural correlates underlying such superior ability in action anticipation. The present event-related potential study compared brain responses from professional badminton players and non-player controls when they watched video clips of badminton games and predicted a ball's landing position. Replicating literature findings, the players made significantly more accurate judgments than the controls and showed better action anticipation. Correspondingly, they showed enlarged amplitudes of two ERP components, a P300 peaking around 350ms post-stimulus with a parietal scalp distribution and a P2 peaking around 250ms with a posterior-occipital distribution. The P300 effect was interpreted to reflect primed access and/or directing of attention to game-related memory representations in the players facilitating their online judgment of related actions. The P2 effect was suggested to reflect some generic learning effects. The results identify clear neural responses that differentiate between different levels of action anticipation associated with sports expertise.

Treatment of death in the analysis of longitudinal studies of gerontological outcomes

BACKGROUND

Longitudinal studies in gerontology are characterized by termination of measurement from death. Death is related to many important gerontological outcomes, such as functional disability, and may, over time, change the composition of an older study population. For these reasons, treating death as noninformative censoring of a longitudinal outcome may result in biased estimates of regression coefficients related to that outcome.

METHODS

In a longitudinal study of community-living older persons, we analytically and graphically illustrate the dependence between death and functional disability. Relative to survivors, decedents display a rapid decline of functional ability in the months preceding death. Death's strong relationship with functional disability demonstrates that death is not independent of this outcome and, hence, leads to informative censoring. We also demonstrate the "healthy survivor effect" that results from death's selection effect, with respect to functional disability, on the longitudinal makeup of an older study population.

RESULTS

We briefly survey commonly used approaches for longitudinal modeling of gerontological outcomes, with special emphasis on their treatment of death. Most common methods treat death as noninformative censoring. However, joint modeling methods are described that take into account any dependency between death and a longitudinal outcome.

CONCLUSIONS

In longitudinal studies of older persons, death is often related to gerontological outcomes and, therefore, cannot be safely assumed to represent noninformative censoring. Such analyzes must account for the dependence between outcomes and death as well as the changing nature of the cohort.

New approach of testing the effect of heat stress on eggshell quality: mechanical and material properties of eggshell and membrane

1. The effect of high temperature on eggshell quality was investigated by measuring the mechanical and material properties of shell and membranes. 2. Heat exposure resulted in a decrease in zootechnical performance and eggshell thickness, increase in egg breakage, and unchanged egg shape index. 3. The static stiffness (Kstat), dynamic stiffness (Kdyn) and modulus of elasticity of the eggshell were not significantly affected by high temperature. Membrane prolongation increased significantly while membrane attachment strength and breakage strength tended to decrease and increase, respectively. The relationships between these variables were changed by high temperature. 4. Neither Kstat nor Kdyn could give a reasonable explanation for the changed eggshell quality induced by heat stress. The decreased eggshell thickness and changed properties of shell membrane may be responsible, at least partially, for the decreased shell quality of eggs from heat-stressed hens.

Long-term outcome of division of the C8 nerve root for spasticity of the hand in cerebral palsy

Division of the C8 nerve root results in short-term relief of spasticity in the hands of cerebral palsy patients. In the present study, we assessed the long-term outcome of C8 nerve root division. Between March 1997 and January 2002, this procedure was done in 13 patients. All received consistent postoperative functional rehabilitation training. The hands were assessed before operation and at follow-up using the Lazareff grading system. The average follow-up time was 8.6 years. Two hands showed excellent improvement, three limbs showed good improvement and eight hands showed no improvement. No long-term complications occurred in any patient. These results indicate that the long-term outcome of C8 nerve root rhizotomy for the treatment of hand spasticity in CP is generally poor.

Rare-earth ions doped heavy metal germanium tellurite glasses for fiber lighting in minimally invasive surgery

In Er(3+)/Yb(3+) codoped Na(2)O-ZnO-PbO-GeO(2)-TeO(2) (NZPGT) glass fiber, a clear and compact green upconversion amplified spontaneous emission (ASE) trace is observed, and the NZPGT glasses are proved to be a desirable candidate in fabricating low-phonon energy fiber. Intense green upconversion luminescence of Er(3+), balanced green and red upconversion emissions of Ho(3+), and dominant three-photon blue upconversion fluorescence of Tm(3+) have been represented. By varying the excitation power of 974 nm wavelength laser diode, a series of green and white fluorescences have been achieved in Tm(3+)/Er(3+)/Yb(3+) and Tm(3+)/Ho(3+)/Yb(3+) triply doped glass systems, respectively. These results reveal that high-intensity blue, green, and white upconversion ASE fluorescences, which can be adopted for lighting in minimally invasive photodynamic therapy and minimally invasive surgery, are reasonable to be expected in rare-earth doped NZPGT glass fibers.

BRG1 expression is increased in human cutaneous melanoma

BACKGROUND

The SWI/SNF chromatin remodelling complex plays important roles in cellular processes including cell differentiation, cell cycle control and DNA repair. Aberrant expression of SWI/SNF subunits is involved in cancer development. The core subunit of the SWI/SNF complex, SNF5, has been shown to be inactivated in malignant rhabdoid tumours and has been defined as a tumour suppressor. However, the role of the catalytic subunit, BRG1, is not well defined in cancer.

OBJECTIVES

To investigate the role of BRG1 in melanoma development, we examined the expression of BRG1 in melanocytic lesions at different stages and analysed the correlation between BRG1 expression and clinicopathological variables and patient survival.

METHODS

Using tissue microarray and immunohistochemistry, we evaluated BRG1 staining in 48 dysplastic naevi, 90 primary melanomas and 47 metastatic melanomas. We studied melanoma cell proliferative ability with reduced BRG1 expression by small interfering RNA using cell proliferation assay and cell cycle analysis.

RESULTS

We found that BRG1 expression was increased in primary melanoma and metastatic melanoma compared with dysplastic naevi (P<0·0001). We did not find any correlation between BRG1 expression and melanoma patient survival. In addition, we demonstrated that knockdown of BRG1 in melanoma cell lines resulted in significantly reduced cell proliferative ability. This reduced cell proliferation is due to G(1) phase arrest as cyclin D(1) is downregulated upon BRG1 knockdown.

CONCLUSIONS

Our data indicate that BRG1 is significantly increased in human melanoma and is involved in melanoma initiation.

Reduced myoelectric activity in the sphincter of Oddi in a new model of chronic cholangitis in rabbits: an in vivo and in vitro study

BACKGROUND

Chronic cholangitis caused by hepatolithiasis is a common disease in Southeast Asia. Few studies have addressed the effects of chronic cholangitis on cyclic activity of the sphincter of Oddi (SO). In this study, we investigated the changes of myoelectric activity in rabbits with chronic cholangitis in vivo and in vitro.

METHODS

Chronic cholangitis was induced in rabbits by initially introducing three pieces of 2-0 silk suture and sequentially injecting E. coli into the choledochus through the tube in ductus cysticus. In in vivo experiments, myoelectric activity of SO was recorded by a circular electrode through the jejunum stump in conscious animals. In in vitro experiments, the SO was completely isolated and the myoelectric activity was recorded by a circular electrode in a 10-mL organ bath filled with Krebs solution, with or without addition of cholecystokinin-8 (CCK-8), KCl, ionomycin or induction of capacitative calcium entry (CCE).

KEY RESULTS

In comparison with control and non-infected rabbits, the rabbits with chronic cholangitis showed higher levels of alkaline phosphatase and gamma-glutamyltransferase and significant pathological changes including increased inflammatory infiltration and collagen deposition in mucosae or muscular layer. Cyclic myoelectric activity of SO at phases 2 and 3 of migrating motor complex and the excitatory response to CCK-8 were dramatically decreased in animals with chronic cholangitis. Myoelectric activity of SO was also significantly decreased in vitro with or without agonists or with induction of CCE.

CONCLUSIONS & INFERENCES

Myoelectric activity of SO and its response to agonists are decreased in rabbits with chronic cholangitis both in vivo and in vitro.