Association of GSTTI and GSTM1 variants with acute myeloid leukemia risk

We aimed to investigate the relationships between polymorphisms of the glutathione S-transferases (GSTs) GSTM1, GSTTI, and GSTP1 and the risk of developing acute myeloid leukemia (AML). A total of 206 AML cases and 231 controls were collected for our study. The genotyping of GSTs (GSTM1, GSTTI, and GSTP1) was based upon the duplex polymerase chain reaction with the confronting two-pair primer (PCR-CTPP) method. Individuals carrying null GSTTI and GSTM1 genotypes had a 1.52- and 1.78-fold increased risk of developing acute leukemia, respectively, compared to non-null genotype carriers (P < 0.05). A high risk was observed in those carrying a combination of null genotypes of GSTM1 and GSTTI with GSTP1-Val allele genotypes when compared with those carrying wild-type genotypes, with an odds ratio (95% confidence interval) of 3.62 (1.53-8.82) (P < 0.05). These findings indicate that genetic variants of GSTTI and GSTM1 significantly increase the risk of developing AML. Our study offers important insights into the molecular etiology of AML.

Enhanced aneurysmal flow diversion using a dynamic push-pull technique: an experimental and modeling study

BACKGROUND AND PURPOSE

Neurovascular flow diverters are flexible, braided stent-meshes for intracranial aneurysm treatment. We applied the dynamic push-pull technique to manipulate the flow-diverter mesh density at the aneurysm orifice to maximize flow diversion. This study investigated the hemodynamic impact of the dynamic push-pull technique on patient-specific aneurysms by using the developed high-fidelity virtual-stenting computational modeling technique combined with computational fluid dynamics.

MATERIALS AND METHODS

We deployed 2 Pipeline Embolization Devices into 2 identical sidewall anterior cerebral artery aneurysm phantoms by using the dynamic push-pull technique with different delivery-wire advancements. We then numerically simulated these deployment processes and validated the simulated mesh geometry. Computational fluid dynamics analysis was performed to evaluate detailed hemodynamic changes by deployed flow diverters in the sidewall aneurysm and a fusiform basilar trunk aneurysm (deployments implemented previously). Images of manipulated flow diverter mesh from sample clinical cases were also evaluated.

RESULTS

The flow diverters deployed in silico accurately replicated in vitro geometries. Increased delivery wire advancement (21 versus 11 mm) by using a dynamic push-pull technique produced a higher mesh compaction at the aneurysm orifice (50% metal coverage versus 36%), which led to more effective aneurysmal inflow reduction (62% versus 50% in the sidewall aneurysm; 57% versus 36% in the fusiform aneurysm). The dynamic push-pull technique also caused relatively lower metal coverage along the parent vessel due to elongation of the flow diverter. High and low mesh compactions were also achieved for 2 real patients by using the dynamic push-pull technique.

CONCLUSIONS

The described dynamic push-pull technique increases metal coverage of pure braided flow diverters over the aneurysm orifice, thereby enhancing the intended flow diversion, while reducing metal coverage along the parent vessel to prevent flow reduction in nearby perforators.

Abstract P4-05-14: Molecular and immunohistochemical profile of invasive micropapillary breast carcinoma

Background: Invasive micropapillary carcinoma (IMPC) of the breast is an uncommon disease subtype that is generally considered aggressive. A variety of carcinomas can exhibit micropapillary histology including lung, bladder, and ovary. Immunohistochemical (IHC) and genomic studies at these other organ sites have identified potential therapeutic targets including BRAF mutations. The purpose of this study was to characterize the IHC and molecular profile of a cohort of IMPC that could suggest potentially useful targeted therapies.

Design: Eight tumor blocks (from seven patients) of IMPC were identified from the archives at the University of Iowa Hospitals and Clinics from 1997-2012. IHC stains for ER, PR, HER2, PTEN (Dako; clone 6H2.1, 1:100) and NM23H1 (Santa Cruz Biotechnology, clone: Nm301, 1:50) were performed. ER, PR, and HER2 were score according to ASCO/CAP guidelines. PTEN and NM23H1 were scored using a 4-tier system: P: strong homogenous; H: heterogeneous (positive with negative foci); R: reduced in more than 50%; and L: lost in all or majority. Genomic DNA was isolated from the formalin fixed paraffin embedded tumor samples used for IHC. BRAF V600 mutational analysis was analyzed using a laboratory-developed primer extension assay. Massive parallel sequencing (next generation sequencing, NGS) was performed using the Ion AmpliSeq™ Cancer Hotspot Panel v2 (Life Technologies, Carlsbad, CA).

Results: The patients were 50-83 years of age. Six had Elston-Ellis Grade II tumors and one was Elston-Ellis grade I. Four patients had axillary lymph node metastases. All cases examined showed strong and diffuse estrogen and progesterone receptor expression with no over-expression of HER2. Complete PTEN loss was observed in 4 cases including 3 with lymph node positive disease, three of these four cases had concurrent reduced expression of NM23H1. No mutations in exon 15 of the BRAF gene were detected. By NGS, one sample showed a KITc.A1621C (pM541) polymorphism, three had no mutations, and sequencing from the other three was unsatisfactory.

Molecular and IHC Profile of Seven Patients with IMPC of the BreastHistologic GradeAxillary Lymph Node MetastasisER/PRHER2PTENNM23H1NGS2NoPositive/PositiveNegativePPUnsatisfactory1NoPositive/PositiveNegativeLRNegative2NoPositive/PositiveNegativeHPIntronic2YesPositive/PositiveNegativeHPUnsatisfactory2YesPositive/PositiveNegativeLRKIT c.A1621C (pM541)2YesPositive/PositiveNegativeLPNegative2YesPositive/PositiveNegativeLRUnsatisfactory

Conclusions: Loss of PTEN expression was observed in 57% of cases (4/7) and was often associated with lymph node metastasis. A direct correlation between PTEN and NM23H1 expression was observed in six cases. No BRAF or other mutations were detected. PTEN was included in the NGS panel. Reduced expression observed in our study is most likely due to posttranscriptional modifications. Concurrent reduced expression of the metastatic suppressor NM23H1 may play a role in the clinical behavior of IMPC. The high frequency of PTEN loss may have implications for targeted therapy towards the PI3K pathway in this subgroup of patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-05-14.

Dexamethasone exacerbates cerebral edema and brain injury following lithium-pilocarpine induced status epilepticus

Anti-inflammatory therapies are the current most plausible drug candidates for anti-epileptogenesis and neuroprotection following prolonged seizures. Given that vasogenic edema is widely considered to be detrimental for outcome following status epilepticus, the anti-inflammatory agent dexamethasone is sometimes used in clinic for alleviating cerebral edema. In this study we perform longitudinal magnetic resonance imaging in order to assess the contribution of dexamethasone on cerebral edema and subsequent neuroprotection following status epilepticus. Lithium-pilocarpine was used to induce status epilepticus in rats. Following status epilepticus, rats were either post-treated with saline or with dexamethasone sodium phosphate (10 mg/kg or 2 mg/kg). Brain edema was assessed by means of magnetic resonance imaging (T₂ relaxometry) and hippocampal volumetry was used as a marker of neuronal injury. T₂ relaxometry was performed prior to, 48 h and 96 h following status epilepticus. Volume measurements were performed between 18 and 21 days after status epilepticus. Unexpectedly, cerebral edema was worse in rats that were treated with dexamethasone compared to controls. Furthermore, dexamethasone treated rats had lower hippocampal volumes compared to controls 3 weeks after the initial insult. The T₂ measurements at 2 days and 4 days in the hippocampus correlated with hippocampal volumes at 3 weeks. Finally, the mortality rate in the first week following status epilepticus increased from 14% in untreated rats to 33% and 46% in rats treated with 2 mg/kg and 10 mg/kg dexamethasone respectively. These findings suggest that dexamethasone can exacerbate the acute cerebral edema and brain injury associated with status epilepticus.

•

Dexamethasone given following seizures caused a worsening of edema and brain injury.

•

This finding also applied to doses dexamethasone as low as 2 mg/kg.

•

We show the use of automated hippocampal volume measurement for therapy monitoring.

Association between oxidative stress and telomere length in Type 1 and Type 2 diabetic patients

BACKGROUND

Increasing evidence showed that telomere length was shorter in age-related diseases, but the mechanism of this phenomenon is still unclear.

AIM

To determine whether telomere shortening occurs in Type 1 diabetes (T1D) and Type 2 diabetes (T2D), and explore the effect of antioxidant status on the telomere length.

SUBJECTS AND METHODS

T2D patients (no.=62), T1D patients (no.=34), and non-diabetic subjects used as control (CTL) (no.=40) were included in this study. Leukocyte telomere length ratio (T/S ratio) was measured using a quantitative PCR and analyzed. Antioxidant status was estimated by human 8-hydroxy-desoxyguanosine quantization. Other biomarkers, such as fasting plasma glucose, fasting insulin, glycated hemoglobin (HbA1c) and lipid profile were also measured.

RESULTS

Compared with CTL group [T/S ratio (mean ± SD), 2.39 ± 0.55], leukocyte telomere length was significantly shorter in T2D group (1.67 ± 0.50) and T1D group (1.77 ± 0.50). 8-OHdG that indicated oxidative stress was significantly higher in T2D (2.99 ± 0.85 ng/ml) and T1D (2.03 ± 0.92 ng/ml) group than in CTL group (0.90 ± 0.46 ng/ml). T/S ratio was significantly negatively correlated with age, waist circumference, waist-to-hip ratio, diastolic blood pressure, fasting plasma glucose, HbA1c, homeostasis model assessment of insulin resistance and 8- OHdG in the whole population. 8-OHdG was independent risk factor for telomere shortening in both T1D (p=0.018) and T2D group (p=0.022).

CONCLUSIONS

In our study, shorter telomere length and increased oxidative stress were observed in both T1D and T2D. Older people with central obesity, hyperglycemia, insulin resistance and severe antioxidant status tended to have shorter telomere length. In addition, 8- OHdG was an independent predictor for telomere length for both T1D and T2D patients.

Neuroprotective effect of resveratrol on arsenic trioxide–induced oxidative stress in feline brain

Arsenic trioxide (As2O3) is a known environmental toxicant and potent chemotherapeutic agent. Significant correlation has been reported between arsenic exposure (including consumption of arsenic-contaminated water and clinical use of As2O3) and dysfunction in the nervous system. In this study, we aimed to elucidate the effect of resveratrol with neuroprotective activities on As2O3-induced oxidative damage and cerebral cortex injury. Twenty-four healthy Chinese Dragon Li cats of either sex were randomly divided into four groups: control (1 ml/kg physiological saline), As2O3 (1 mg/kg), resveratrol (3 mg/kg) and As2O3 (1 mg/kg) + resveratrol (3 mg/kg). As2O3+resveratrol-treated group were given resveratrol (3 mg/kg) 1 h before As2O3 (1 mg/kg) administration. Pretreatment with resveratrol upregulated the activities of antioxidant enzymes and attenuated As2O3-induced increases in reactive oxygen species and malondialdehyde production. In addition, resveratrol attenuated the As2O3-induced reduction in the level of reduced glutathione and the ratio of reduced glutathione to oxidised glutathione, and accumulation of arsenic in the cerebral cortex. These findings support neuroprotective effect of resveratrol on As2O3 toxicity in feline brain and provide a better understanding of the mechanism that resveratrol modulates As2O3-induced oxidative damage and a stronger rational for clinical use of resveratrol to protect brain against the toxicity of arsenic.

Cariogenic bacteria degrade dental resin composites and adhesives

A major reason for dental resin composite restoration replacement is related to secondary caries promoted by acid production from bacteria including Streptococcus mutans (S. mutans). We hypothesized that S. mutans has esterase activities that degrade dental resin composites and adhesives. Standardized specimens of resin composite (Z250), total-etch (Scotchbond Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 or uninoculated culture medium (control) for up to 30 days. Quantification of the BisGMA-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP), was performed by high-performance liquid chromatography. Surface analysis of the specimens was performed by scanning electron microscopy (SEM). S. mutans was shown to have esterase activities in levels comparable with those found in human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was more elevated in the presence of bacteria vs. control medium for EB and Z250, but not for SB (p < .05). SEM confirmed the increased degradation of all materials with S. mutans UA159 vs. control. S. mutans has esterase activities at levels that degrade resin composites and adhesives; degree of degradation was dependent on the material's chemical formulation. This finding suggests that the resin-dentin interface could be compromised by oral bacteria that contribute to the progression of secondary caries.

Xenon treatment protects against cold ischemia associated delayed graft function and prolongs graft survival in rats

Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia-hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival.

Anaesthetic neurotoxicity and neuroplasticity: an expert group report and statement based on the BJA Salzburg Seminar

Although previously considered entirely reversible, general anaesthesia is now being viewed as a potentially significant risk to cognitive performance at both extremes of age. A large body of preclinical as well as some retrospective clinical evidence suggest that exposure to general anaesthesia could be detrimental to cognitive development in young subjects, and might also contribute to accelerated cognitive decline in the elderly. A group of experts in anaesthetic neuropharmacology and neurotoxicity convened in Salzburg, Austria for the BJA Salzburg Seminar on Anaesthetic Neurotoxicity and Neuroplasticity. This focused workshop was sponsored by the British Journal of Anaesthesia to review and critically assess currently available evidence from animal and human studies, and to consider the direction of future research. It was concluded that mounting evidence from preclinical studies reveals general anaesthetics to be powerful modulators of neuronal development and function, which could contribute to detrimental behavioural outcomes. However, definitive clinical data remain elusive. Since general anaesthesia often cannot be avoided regardless of patient age, it is important to understand the complex mechanisms and effects involved in anaesthesia-induced neurotoxicity, and to develop strategies for avoiding or limiting potential brain injury through evidence-based approaches.

Impact of anaesthetics and surgery on neurodevelopment: an update

Accumulating preclinical and clinical evidence suggests the possibility of neurotoxicity from neonatal exposure to general anaesthetics. Here, we review the weight of the evidence from both human and animal studies and discuss the putative mechanisms of injury and options for protective strategies. Our review identified 55 rodent studies, seven primate studies, and nine clinical studies of interest. While the preclinical data consistently demonstrate robust apoptosis in the nervous system after anaesthetic exposure, only a few studies have performed cognitive follow-up. Nonetheless, the emerging evidence that the primate brain is vulnerable to anaesthetic-induced apoptosis is of concern. The impact of surgery on anaesthetic-induced brain injury has not been adequately addressed yet. The clinical data, comprising largely retrospective cohort database analyses, are inconclusive, in part due to confounding variables inherent in these observational epidemiological approaches. This places even greater emphasis on prospective approaches to this problem, such as the ongoing GAS trial and PANDA study.

Levels of components of the urokinase-type plasminogen activator system are related to chronic obstructive pulmonary disease parenchymal destruction and airway remodelling

OBJECTIVE

Retrospective study to investigate levels of components of the urokinase-type plasminogen activator (uPA) system in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Peripheral lung tissue was obtained from patients who underwent surgical resection for benign lung diseases: 16 patients with COPD, 10 controls without lung function impairment who were smokers, and 10 controls without lung function impairment who were nonsmokers. Immunohistochemical staining for uPA, uPA receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1) was quantified. Airway remodelling (collagen; detected by Sirius red staining), lung function (determined by spirometry) and emphysema (alveolar destruction; percentage of low attenuation areas on computed tomography scan) were evaluated.

RESULTS

uPA, uPAR and PAI-1 were significantly different in structural lung cells and pulmonary macrophages from patients with COPD compared with controls. There were significant positive correlations between collagen levels and uPA and PAI-1, and between uPA and degree of emphysema. There were significant inverse correlations between lung function and uPA, uPAR and PAI-1.

CONCLUSION

Correlations between components of the uPA system and lung function, small airway fibrosis and emphysema indicate a role for the uPA system in COPD.

Ductilizing bulk metallic glass composite by tailoring stacking fault energy

Martensitic transformation was successfully introduced to bulk metallic glasses as the reinforcement micromechanism. In this Letter, it was found that the twinning property of the reinforcing crystals can be dramatically improved by reducing the stacking fault energy through microalloying, which effectively alters the electron charge density redistribution on the slipping plane. The enhanced twinning propensity promotes the martensitic transformation of the reinforcing austenite and, consequently, improves plastic stability and the macroscopic tensile ductility. In addition, a general rule to identify effective microalloying elements based on their electronegativity and atomic size was proposed.

Pulsed laser ablation based direct synthesis of single-wall carbon nanotube/PbS quantum dot nanohybrids exhibiting strong, spectrally wide and fast photoresponse

Pulsed laser ablation for the direct synthesis of single-wall carbon nanotube/PbS-quantumdot(SWCNT/PbS-QD) nanohybrids is demonstrated. The latitude of the developed pulsed laser deposition process permits not only the control of the size of the PbS-QDs but also the straightforward integration of these novel SWCNT/PbS-QD nanohybrids into photoconductive (PC) devices. Thus, by optimizing the nanohybrid characteristics, PC devices exhibiting not only fast but also strong photoresponse (as high as 1350% at 405 nm) are achieved.

Mutations in the tail domain of DYNC1H1 cause dominant spinal muscular atrophy

OBJECTIVE

To identify the gene responsible for 14q32-linked dominant spinal muscular atrophy with lower extremity predominance (SMA-LED, OMIM 158600).

METHODS

Target exon capture and next generation sequencing was used to analyze the 73 genes in the 14q32 linkage interval in 3 SMA-LED family members. Candidate gene sequencing in additional dominant SMA families used PCR and pooled target capture methods. Patient fibroblasts were biochemically analyzed.

RESULTS

Regional exome sequencing of all candidate genes in the 14q32 interval in the original SMA-LED family identified only one missense mutation that segregated with disease state-a mutation in the tail domain of DYNC1H1 (I584L). Sequencing of DYNC1H1 in 32 additional probands with lower extremity predominant SMA found 2 additional heterozygous tail domain mutations (K671E and Y970C), confirming that multiple different mutations in the same domain can cause a similar phenotype. Biochemical analysis of dynein purified from patient-derived fibroblasts demonstrated that the I584L mutation dominantly disrupted dynein complex stability and function.

CONCLUSIONS

We demonstrate that mutations in the tail domain of the heavy chain of cytoplasmic dynein (DYNC1H1) cause spinal muscular atrophy and provide experimental evidence that a human DYNC1H1 mutation disrupts dynein complex assembly and function. DYNC1H1 mutations were recently found in a family with Charcot-Marie-Tooth disease (type 2O) and in a child with mental retardation. Both of these phenotypes show partial overlap with the spinal muscular atrophy patients described here, indicating that dynein dysfunction is associated with a range of phenotypes in humans involving neuronal development and maintenance.

Elastic moduli inheritance and the weakest link in bulk metallic glasses

We show that a variety of bulk metallic glasses (BMGs) inherit their Young's modulus and shear modulus from the solvent components. This is attributed to preferential straining of locally solvent-rich configurations among tightly bonded atomic clusters, which constitute the weakest link in an amorphous structure. This aspect of inhomogeneous deformation, also revealed by our in situ neutron diffraction studies of an elastically deformed BMG, suggests a rubberlike viscoelastic behavior due to a hierarchy of atomic bonds in BMGs.