Brief report: ectopic expression of NUP98-HOXA10 augments erythroid differentiation of human embryonic stem cells

Hox genes encode highly conserved transcription factors that have been implicated in hematopoietic development and self-renewal of hematopoietic stem cells (HSCs) and hematopoietic development. The potency of NUP98-HOXA10hd (NA10) on adult murine bone marrow HSC self-renewal prompted us to examine its effect on specification and proliferation of hematopoietic cells derived from human embryonic stem cells (hESCs). Here, we demonstrate that expression of NA10 in hESCs influences the hematopoietic differentiation program. The specific effect of NA10 is dependent on the developmental stage of hematopoietic emergence from hESCs. Overexpression of NA10 in either undifferentiated hESCs or early hemogenic precursors augmented the frequency of CD45(-) GlycophorinA(+) cells and erythroid progenitors (blast-forming unit-erythrocyte). In contrast, targeted NA10 expression in primitive CD34+ cells committed to the hematopoietic lineage had no effect on erythropoietic capacity but instead increased hematopoietic progenitor proliferation. Our study reveals a novel neomorphic effect of NA10 in early human erythroid development from pluripotent stem cells.

The Determination of Mechanical Parameters and Residual Stresses for Thin Films Using Micro-Cantilever Beams

A method for determining mechanical parameters and residual stresses for thin films is described. Multi-layer cantilever beams (LPCVD SiNx/thermal SiO2) are fabricated utilizing standard IC processing technologies and micromachining of silicon. The elastic response of the beams to imposed deflections is then measured using a Nanoindenter, a sub-micron hardness testing machine. The elastic constants of the nitride films are calculated from the force vs. deflection slope and known elastic constants of the thermal SiO2 and silicon. By measuring the curvature of the multi-layer cantilever beams with a scanning electron microscope after successive etching of the LPCVD nitride films, average and differential stresses in the films were calculated.

Measuring the Strength and Stiffness of Thin Film Materials by Mechanically Deflecting Cantilever Microbeams

The present authors recently introduced the mechanical deflection of cantilever microbeams as an experimental technique for measuring the strength and stiffness of thin films.[1] The technique utilizes conventional integrated circuit (IC) fabrication to process the samples, a Nanoindenter to deflect the cantilever beams mechanically, and simple elastic beam theory to analyze the data. This paper will review the technique and describe some of its current applications.

A feasibility study of magnetic separation of magnetic nanoparticle for forward osmosis

It was recently reported that a UK company has developed a naturally non-toxic magnetoferritin to act as a draw solute for drawing water in forward osmosis process. The gist of this technology is the utilization of the magnetic nanoparticle and high-gradient magnetic separation for draw solute separation and reuse. However, any demonstration on this technology has not been reported yet. In this study, a feasibility test of magnetic separation using magnetic nanoparticle was therefore performed to investigate the possibility of magnetic separation in water treatment such as desalination. Basically, a magnetic separation system consisted of a column packed with a bed of magnetically susceptible wools placed between the poles of electromagnet and Fe3O4 magnetic nanoparticle was used as a model nanoparticle. The effect of nanoparticle size to applied magnetic field in separation column was experimentally investigated and the magnetic field distribution in a magnet gap and the magnetic field gradient around stainless steel wool wire were analyzed through numerical simulation. The amount of magnetic nanoparticle captured in the separator column increased as the magnetic field strength and particle size increased. As a result, if magnetic separation is intended to be used for draw solute separation and reuse, both novel nanoparticle and large-scale high performance magnetic separator must be developed.

Abstract P6-09-02: Risk of Breast Cancer Associated with Hormone Replacement Therapy Use Differs by Age, Race, and Breast Density

Background: Observational studies and randomized trials have demonstrated an association between hormone replacement therapy (HRT) use and increased risk for breast cancer. However, this risk may vary by age and other factors, including breast density and race/ethnicity. Using data from the Breast Cancer Surveillance Consortium (BCSC), we investigate whether self-reported HRT use in the peri-menopausal and immediate post-menopausal age groups is associated with breast cancer, and also whether risk associated with HRT use differs by breast density and race. Subjects and Methods: The BCSC is a longitudinal registry of mammography screening in seven U.S. centers. In the breast cancer risk prediction model developed by Barlow et al (J Natl Cancer Inst 2006 98:1204-14), HRT use and ten other features were identified as risk factorsfor breast cancer. Data for our study consists of 1,642,824 screens and 9,300 breast cancers among the post-menopausal women aged > 44 in this cohort. Logistic regression models were used to estimate odds ratios for breast cancer associated with HRT use within race, age, and density strata, adjusting for other variables from the Barlow model. Multiple imputation methods were used to accommodate missing data for HRT (14%) and other predictors.

Results: Breast cancer risk for HRT use varied by age, with no risk excess among women aged 45-49 and risk excess of 20% or greater for women aged 50-64 (Table 1). Women >64 had a smaller excess risk with HRT use. There was no significant excess risk at any age for Black women, while White women age 50-64 had > 20% excess risk for HRT use. White women with higher breast density had increased risk with HRT use, while Black women did not.

Table 1: Odds ratios (95% confidence interval) for HRT use (yes/no)

Conclusions: In this large cohort of mammography-screened women, HRT use did not increase breast cancer risk in the peri-menopausal period (age 45-49). Women with low breast density had smaller risk increments associated with HRT than those with high density. For Black women, increased breast cancer risk due to HRT was not apparent at any age or breast density category.

Data collection for the BCSC was supported by a NCI-funded Breast Cancer Surveillance Consortium co-operative agreement (U01CA63740, U01CA86076, U01CA86082, U01CA63736, U01CA70013, U01CA69976, U01CA63731, U01CA70040).

Surgical treatment for localization-related infantile spasms: excellent long-term outcomes

OBJECTIVE

Focal epileptogenic lesions can manifest as infantile spasms, a catastrophic type of epilepsy. Although early surgery for catastrophic epilepsies has shown positive effects, little is known regarding long-term outcomes. The present study examined long-term outcomes in patients with localization-related infantile spasms treated surgically.

METHODS

Data from localization-related infantile spasm cases treated surgically between 1998 and 2002 at the Asan Medical Center were retrospectively reviewed. Presurgical evaluation, surgery, postoperative seizure frequency and developmental outcome data were analyzed.

RESULTS

Five patients met the inclusion criteria, and had etiologies of tuberous sclerosis, fetal infection, encephalomalacia, malformation of cortical development and low-grade astrocytoma, respectively. The mean seizure onset age was 5.4 months (range, 3 days to 11 months), and the mean age at surgery was 19 months (range, 9-29 months). Two patients underwent a functional hemispherectomy, and the remaining three underwent lesionectomy or temporal lobectomy. The follow-up duration was 6-9 years. We found that following surgery, 4 of the 5 patients were seizure-free at the final follow-up. The 2 patients with low grade astrocytoma and cortical dysplasia, respectively showed relatively good developmental outcomes.

CONCLUSION

Surgery may be an excellent option for treating selected patients with infantile spasms due to unilateral or focal congenital or early-acquired cortical lesions. However, developmental outcomes appear to be strongly linked to etiology and the pre-operative developmental level.