High density of REC8 constrains sister chromatid axes and prevents illegitimate synaptonemal complex formation.

During meiosis, cohesin complexes mediate sister chromatid cohesion (SCC), synaptonemal complex (SC) assembly and synapsis. Here, using super-resolution microscopy, we imaged sister chromatid axes in mouse meiocytes that have normal or reduced levels of cohesin complexes, assessing the relationship between localization of cohesin complexes, SCC and SC formation. We show that REC8 foci are separated from each other by a distance smaller than 15% of the total chromosome axis length in wild-type meiocytes.

Microchip Screening Platform for Single Cell Assessment of NK Cell Cytotoxicity.

Here, we report a screening platform for assessment of the cytotoxic potential of individual natural killer (NK) cells within larger populations. Human primary NK cells were distributed across a silicon-glass microchip containing 32,400 individual microwells loaded with target cells. Through fluorescence screening and automated image analysis, the numbers of NK and live or dead target cells in each well could be assessed at different time points after initial mixing.

Modulated fluorescence of colloidal quantum dots embedded in a porous alumina membrane.

The fluorescence spectrum of CdSe core-CdS/ZnS shell colloidal quantum dots (QDs) embedded in porous alumina membrane was studied. Small peaks, superimposed on the principal QD fluorescence spectrum, were observed. Finite-difference time-domain simulation indicates that the QD point radiation emitting from within the membrane is strongly modulated by the photonic band structure introduced by the membrane pores, leading to the observed fine spectral features.

Pulmonary delivery of d-methionine is associated with an increase in ALCAR and glutathione in cochlear fluids.

In animals, hearing loss resulting from cochlear mechanosensory cell damage can be mitigated by antioxidants such as d-methionine (d-met) and acetyl-l-carnitine (ALCAR). The systemic routes of administration of these compounds, that must of necessity transit trough the cochlear fluids, may affect the antioxidant levels in the cochlea and the resulting oto-protective effect. In this study, we analyzed the pharmacokinetics of [(14)C]d-met in the cochlea and four other tissues after intratracheal (IT), intranasal (IN), and oral by gavage (OG) administration and compared it to intravenous administration (IV).

Host-derived pericytes and Sca-1+ cells predominate in the MART-1- stroma fraction of experimentally induced melanoma.

Identification of cell types in tumor-associated stroma that are involved in the development of melanoma is hampered by their heterogeneity. The authors used flow cytometry and immunohistochemistry to demonstrate that anti-MART-1 antibodies can discriminate between melanoma and stroma cells. They investigated the cellular composition of the MART-1-, non-hematopoietic melanoma-associated stroma, finding it consisted mainly of Sca-1+ and CD146+ cells.

Imaging immune surveillance of individual natural killer cells confined in microwell arrays.

New markers are constantly emerging that identify smaller and smaller subpopulations of immune cells. However, there is a growing awareness that even within very small populations, there is a marked functional heterogeneity and that measurements at the population level only gives an average estimate of the behaviour of that pool of cells. New techniques to analyze single immune cells over time are needed to overcome this limitation.

Ultrasound-controlled cell aggregation in a multi-well chip.

We demonstrate a microplate platform for parallelized manipulation of particles or cells by frequency-modulated ultrasound. The device, consisting of a silicon-glass microchip and a single ultrasonic transducer, enables aggregation, positioning and high-resolution microscopy of cells distributed in an array of 100 microwells centered on the microchip. We characterize the system in terms of temperature control, aggregation and positioning efficiency, and cell viability.

Spatial confinement of ultrasonic force fields in microfluidic channels.

We demonstrate and investigate multiple localized ultrasonic manipulation functions in series in microfluidic chips. The manipulation functions are based on spatially separated and confined ultrasonic primary radiation force fields, obtained by local matching of the resonance condition of the microfluidic channel. The channel segments are remotely actuated by the use of frequency-specific external transducers with refracting wedges placed on top of the chips.