On the prevalence of small-scale twist in the solar chromosphere and transition region

The solar chromosphere and transition region (TR) form an interface between the Sun's surface and its hot outer atmosphere. There, most of the nonthermal energy that powers the solar atmosphere is transformed into heat, although the detailed mechanism remains elusive. High-resolution (0.33-arc second) observations with NASA's Interface Region Imaging Spectrograph (IRIS) reveal a chromosphere and TR that are replete with twist or torsional motions on sub-arc second scales, occurring in active regions, quiet Sun regions, and coronal holes alike. We coordinated observations with the Swedish 1-meter Solar Telescope (SST) to quantify these twisting motions and their association with rapid heating to at least TR temperatures. This view of the interface region provides insight into what heats the low solar atmosphere.

Hot explosions in the cool atmosphere of the Sun

The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for the chromosphere and corona that constitute the outer atmosphere, which is now considered a dynamic structured envelope. Recent observations by the Interface Region Imaging Spectrograph (IRIS) reveal that it is difficult to determine what is up and down, even in the cool 6000-kelvin photosphere just above the solar surface: This region hosts pockets of hot plasma transiently heated to almost 100,000 kelvin. The energy to heat and accelerate the plasma requires a considerable fraction of the energy from flares, the largest solar disruptions. These IRIS observations not only confirm that the photosphere is more complex than conventionally thought, but also provide insight into the energy conversion in the process of magnetic reconnection.

Preterm birth and risk of type 1 and type 2 diabetes: systematic review and meta-analysis

Preterm birth is suggested to play an important role in the development of diabetes. However, results have been inconsistent. We conducted a systematic review and meta-analysis to clarify the relationship between preterm birth and type 1 and type 2 diabetes. PubMed, Embase and ISI Web of Science were searched. A total of 18 studies (including 2,176,480 participants and 22,073 cases) for type 1 diabetes and five studies (including 31,478 participants and 1,898 cases) for type 2 diabetes were included in the current meta-analyses. We calculated pooled odds ratio (OR) and 95% confidence interval (CI) using fixed-effects model to evaluate the relations between preterm birth and type 1 and type 2 diabetes. The results suggested that preterm birth was significantly associated with increased risk of type 1 diabetes (OR = 1.18, 95% CI = 1.11-1.25), with no evidence of between-study heterogeneity (I(2) = 13.2%, P = 0.296). Preterm birth was also significantly associated with increased risk of type 2 diabetes (OR = 1.51, 95% CI = 1.32-1.72), with no evidence of (I(2) = 0.0%, P = 0.557). Subgroup analyses suggested that there was significant association in both case-control studies (OR = 1.16, 95% CI = 1.06-1.26) and cohort studies (relative risk = 1.20, 95% CI = 1.11-1.29) for type 1 diabetes, and similar results were found for type 2 diabetes. The results suggested that preterm birth was a significant and independent risk factor for both type 1 and type 2 diabetes.

Abstract 4516: Evaluation of p70S6K/Akt inhibitor MSC2363318A in patient derived xenograft (PDX) models of breast cancer

The PI3K pathway is involved in the regulation of cell growth, proliferation, metabolism and other functions. Aberrant signaling (PTEN loss of function, PIK3CA mutation, Akt amplification, etc.) from the PI3K pathway is observed in >50% of all tumors. Clinical evidence suggests that inhibiting the PI3K pathway is beneficial for the treatment of solid tumors and tumors of the hematopoietic system. Inhibition of mTOR via rapalogs has been shown to block a negative feedback loop, thereby leading to the activation of Akt. The activation of this Akt feedback loop has been suggested to potentially compromise the clinical efficacy of selective mTORC1 inhibitors such as temsirolimus and everolimus. Dual p70S6K/Akt inhibition may promote improved pathway inhibition and also block the negative consequences of Akt activation through the negative feedback loop.

MSC2363318A is a highly selective, potent, adenosine triphosphate (ATP) competitive inhibitor of p70S6K, Akt1, and Akt3. In a cellular context, inhibition of p70S6K leads to potent inhibition of ribosomal protein S6 phosphorylation, while inhibition of Akt activity blocks the negative effects of a compensatory feedback loop. In addition, MSC2363318A exhibits potent anti-proliferative activity against many solid tumor cell lines in vitro, especially those with PI3K pathway genomic alterations. Further, MSC2363318A can also cross the blood-brain barrier (via pre-clinical studies in mice, rat, and dog), a unique characteristic that would allow for treating not only malignancies that are driven by PI3K pathway genomic alterations, but also indications with a high incidence of CNS metastases and primary malignancies of the central nervous system.

Patient Derived Xenograft (PDX) models from breast cancers with a high prevalence of PI3K pathway genomic alterations; including, triple negative breast cancer and Her2+ breast cancer were evaluated. In addition, combinations with standard of care agents were then evaluated in these breast cancer PDX models. Results from these studies were correlated with PI3K pathway genomic modifications, and will be used to guide subsequent clinical studies.

Citation Format: Bayard R. Huck, H Tian, Sakeena Syed, Jing Lin, Jianguo Ma, Anderson Clark, Remiguisz Kaleta, Andreas Machl, Erik Wilker, Marc Lecomte. Evaluation of p70S6K/Akt inhibitor MSC2363318A in patient derived xenograft (PDX) models of breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4516. doi:10.1158/1538-7445.AM2014-4516

12/15-Lipoxygenase deficiency reduces densities of mesenchymal stem cells in the dermis of wounded and unwounded skin

BACKGROUND

Mesenchymal stem cells (MSCs) promote skin healing. 12/15-Lipoxgenase (LOX) is crucial in producing specific lipid mediators in wounded skin. The consequences of 12/15-LOX deficiency in MSC densities in skin are unknown.

OBJECTIVES

To determine the effect of 12/15-LOX deficiency in MSC densities in wounded and unwounded dermis.

METHODS

Full-thickness skin incisional wounds were made to 12/15-LOX-deficient (12/15-LOX(-/-) ) and wild-type (WT) C57BL/6 mice. Wounded skin was collected at 3, 8, or 14 days postwounding (dpw). MSCs were analysed in skin sections using histology. 12S- or 15S-hydroxy-eicosatetraenoic acid (HETE) was analysed using a reversed-phase Chiral liquid chromatography-ultraviolet-tandem mass spectrometer.

RESULTS

There were more stem cell antigen (Sca)1(+) CD29(+) MSCs (cells/field) at 3, 8, and 14 dpw, more Sca1(+) CD106(+) MSCs at 3 and 14 dpw in the wounded dermis, more MSCs in unwounded dermis of WT mice compared with 12/15-LOX(-/-) mice, and more MSCs in the wounded dermis than in the unwounded dermis. For 12/15-LOX(-/-) dermis, Sca1(+) CD106(+) MSCs peaked and Sca1(+) CD29(+) MSCs reached a flat level at 8 dpw. However, for the WT dermis, MSCs increased from 8 to 14 dpw. There were more Sca1(+) CD106(+) MSCs than Sca1(+) CD29(+) MSCs in the 12/15-LOX(-/-) wounded dermis at 8 dpw. However, there were more Sca1(+) CD29(+) MSCs in the 12/15-LOX(-/-) than Sca1(+) CD106(+) MSCs in the WT wounded dermis at 3 dpw, and Sca1(+) CD106(+) MSCs and Sca1(+) CD29(+) MSCs were at comparable levels in other conditions. 12/15-LOX deficiency suppressed levels of 12/15-LOX protein and their products, 12S-HETE and 15S-HETE, in wounds.

CONCLUSIONS

12/15-LOX deficiency reduces MSC densities in the dermis, which correlates with the suppressed 12/15-LOX pathways in wounded and unwounded skin.

Subretinal transplantation of rat MSCs and erythropoietin gene modified rat MSCs for protecting and rescuing degenerative retina in rats

For degenerative retinal diseases, like the acquired form exemplified by age-related macular degeneration (AMD), there is currently no cure. This study was to explore a stem cell therapy and a stem cell based gene therapy for sodium iodate (SI)-induced retinal degeneration in rats. Three cell types, i.e., rat mesenchymal stem cells (rMSCs) alone, erythropoietin (EPO) gene modified rMSCs (EPO-rMSCs) or doxycycline (DOX) inducible EPO expression rMSCs (Tet-on EPO-rMSCs), were transplanted into the subretinal spaces of SI-treated rats. The rMSCs were prepared for transplantation after 3 to 5 passages or modified with EPO gene. During the 8 weeks after the transplantation, the rats treated with rMSCs alone or with two types of EPO-rMSCs were all monitored with fundus examination, fundus fluorescein angiography (FFA) and electroretinogram. The transplantation efficiency of donor cells was examined for their survival, integration and differentiation. Following the transplantation, labeled donor cells were observed in subretinal space and adopted RPE morphology. EPO concentration in vitreous and retina of SI-treated rats which were transplanted with EPO-rMSCs or Tet-on EPO-rMSCs was markedly increased, in parallel with the improvement of retinal morphology and function. These findings suggest that rMSCs transplantation could be a new therapy for degenerative retinal diseases since it can protect and rescue RPE and retinal neurons, while EPO gene modification to rMSCs could be an even better option.

Gamma-glutamyltransferase predicts increased risk of mortality: a systematic review and meta-analysis of prospective observational studies

The aim of this study was to evaluate the association between gamma-glutamyltransferase (GGT) and mortality through a comprehensive analysis of existing evidence. PubMed, Embase, Chinese Biomedical Literature, and Science Citation Index databases were electronically searched. Studies were included if the study design was prospective and included reference and at-risk levels of GGT at baseline and mortality as a separate outcome. The quality of the studies included was assessed on the basis of Newcastle-Ottawa scale. Data from selected qualified studies were systematically reviewed, pooled, and analyzed according to the MOOSE guidelines and PRISMA statement. The results included the following: 1. 35 studies including 571,511 participants and 72,196 cases of mortality; 2. GGT, even at physiologic levels, was associated with increased all-cause mortality and cardiovascular mortality, and might also be associated with cancer-related mortality in the general population; and 3. GGT was very likely to be associated with all-cause mortality and cardiovascular mortality in patients with coronary artery disease and type 2 diabetes mellitus. Many of the studies included did not specifically exclude subjects with hepatic diseases or alcohol abuse, which may have obscured the results. Moderate heterogeneity was observed in the meta-analysis of GGT and all-cause mortality. Different compositions of cause-specific mortality might be the reason. However, subgroup analysis could only be performed on cardiovascular death because of insufficient information. GGT, even at physiologic high levels, predicted mortality, especially cardiovascular mortality and cancer mortality. The underlining mechanism and potential effects of GGT-targeted intervention on health warrant further investigation.

Effects of green tea or green tea extract on insulin sensitivity and glycaemic control in populations at risk of type 2 diabetes mellitus: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Although the regular consumption of green tea or green tea extract has been considered to improve insulin sensitivity, the reported results are inconsistent. Therefore, we conducted a meta-analysis to evaluate the effect of green tea or green tea extract on insulin sensitivity and glycaemic control in populations at risk of type 2 diabetes mellitus (T2DM).

METHODS

Electronic databases, including PUBMED, The Cochrane Library, EMBASE, ISI Web of Knowledge, Chinese Biomedical Literature Database and Chinese Scientific Journals Fulltext Database, were systematically searched to identify randomised controlled trials (RCTs) up to December 2011, supplemented by the Clinicaltrials.gov websites and the reference lists of identified studies. Two reviewers independently selected trials, extracted data, and evaluated the methodological qualities and evidence levels.

RESULTS

Seven RCTs involving 510 participants were identified. There was no statistically significant difference between green tea or green tea extract group and placebo group with regard to fasting plasma glucose [standardised mean difference (SMD) 0.04; 95% confidence interval (CI) -0.15 to 0.24], fasting serum insulin (SMD -0.09; 95% CI -0.30 to 0.11), 2-h plasma glucose in the oral glucose tolerance test (OGTT-2 h) (SMD -0.14; 95% CI -0.63 to 0.34), haemoglobin A₁c (SMD 0.10; 95% CI -0.13 to 0.33) and homeostasis model of insulin resistance (HOMA(IR)) index (SMD -0.06; 95% CI -0.35 to 0.23) in participants at risk of T2DM.

CONCLUSIONS

The consumption of green tea did not decrease the levels of fasting plasma glucose, fasting serum insulin, OGTT-2 h glucose, haemoglobin A₁c and HOMA(IR) in populations at risk of T2DM. Larger, longer-term and high-quality RCTs are needed to further definitely determine the effect of green tea or green tea extract on insulin sensitivity and glycaemic control in populations at risk of T2DM.

Cognitive trio: relationship with major depression and clinical predictors in Han Chinese women

BACKGROUND

Previous studies support Beck's cognitive model of vulnerability to depression. However, the relationship between his cognitive triad and other clinical features and risk factors among those with major depression (MD) has rarely been systematically studied.

METHOD

The three key cognitive symptoms of worthlessness, hopelessness and helplessness were assessed during their lifetime worst episode in 1970 Han Chinese women with recurrent MD. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression.

RESULTS

Compared to patients who did not endorse the cognitive trio, those who did had a greater number of DSM-IV A criteria, more individual depressive symptoms, an earlier age at onset, a greater number of episodes, and were more likely to meet diagnostic criteria for melancholia, postnatal depression, dysthymia and anxiety disorders. Hopelessness was highly related to all the suicidal symptomatology, with ORs ranging from 5.92 to 6.51. Neuroticism, stressful life events (SLEs) and a protective parental rearing style were associated with these cognitive symptoms.

CONCLUSIONS

During the worst episode of MD in Han Chinese women, the endorsement of the cognitive trio was associated with a worse course of depression and an increased risk of suicide. Individuals with high levels of neuroticism, many SLEs and high parental protectiveness were at increased risk for these cognitive depressive symptoms. As in Western populations, symptoms of the cognitive trio appear to play a central role in the psychopathology of MD in Chinese women.