Nanomechanical measurement of adhesion and migration of leukemia cells with phorbol 12-myristate 13-acetate treatment

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Mechanical oscillations enhance gene delivery into suspended cells

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Risk Factors and Post-Resection Independent Predictive Score for the Recurrence of Hepatitis B-Related Hepatocellular Carcinoma

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Risk factors and post-resection independent predictive score for the recurrence of hepatitis B-related hepatocellular carcinoma

BACKGROUND: Independent risk factors associated with hepatitis B virus (HBV)–related hepatocellular carcinoma (HCC) after resection remains unknown. An accurate risk score for HCC recurrence is lacking ...postprin

CD4saurus Rex &HIVelociraptor vs. development of clinically useful immunological markers: a Jurassic tale of frozen evolution

One of the most neglected areas of everyday clinical practice for HIV physicians is unexpectedly represented by CD4 T cell counts when used as an aid to clinical decisions. All who care for HIV patients believe that CD4+ T cell counts are a reliable method to evaluate a patient immune status. There is however a fatalistic acceptance that besides its general usefulness, CD4+ T cell counts have relevant clincal and immunological limits. Shortcomings of CD4 counts appear in certain clinical scenarios including identification of immunological nonresponders, subsequent development of cancer on antiretroviral teatment, failure on tretment simplification. Historical and recently described parameters might be better suited to advise management of patients at certain times during their disease history. Immunogenotypic parameters and innate immune parameters that define progression as well as immune parameters associated with immune recovery are available and have not been introduced into validation processes in larger trials. The scientific and clinical community needs an effort in stimulating clinical evolution of immunological tests beyond "CD4saurus Rex" introducing new parameters in the clinical arena after appropriate validatio

Nanomechanical study of vimentin intermediate filament

Oral Presentation - Session 2: Reproduction & Development, Musculoskeletal System and Cell Biology: 2.21The 16th Research Postgraduate Symposium (RPS 2011), the University of Hong Kong, Hong Kong, 7-8 December 2011

Nanomechanical properties of vimentin intermediate filament

Vimentin intermediate filament (IF) is one of the major proteins which built the cytoskeleton network alongside with the microtubule and actin filament. Though it was known that the vimentin IF network plays an important role in the mechanical behaviours of cells, it is surprised that its mechanical behaviours are not fully understood to date. The aim of this paper is to study the nanomechanical properties of vimentin IF using the atomic force spectroscopy (AFM) which allows the manipulation and force spectroscopy of filaments. The vimentin intermediate filaments were attached to the APTES (3- aminopropyltriethoxy) functionalized mica which offered better adhesive force. In the force spectroscopy study, the AFM tip was allowed to clamp filaments and then retraced. The force-displacement curve of the process was obtained for analysis. The curves can be grouped into two major groups - sewtooth and plateau. The appearance of sewtooth was more frequent than the plateau. The sudden force changes (jumps from higher to lower force) in sewtooth and plateau curves were also analyzed. It was shown that the partial ruptures which denoted by the jumps favoured small force (∼100 pN) and short range (separation of jumps below 25 nm). This result also demonstrated the probability of different modes of partial IF ruptures. © (2012) Trans Tech Publications.link_to_subscribed_fulltex

Magnetic coupling calculations using partial inductance theory

Quantitative analysis of magnetic coupling problems involves the calculations of self inductance of conductors, mutual inductance between conductors, and inductive coupling coefficient etc. It is an issue of great interest along the whole electromagnetics evolvement history. Formerly, the calculations have to be carried out with the aid of three-dimentional EDA solvers by discretization of the entire volume. This is rather tedious and computationally expensive. Engineers may need a simple approach to estimate the inductance values without any complex computational tools. In this paper, we propose a new method to fulfill this task based on partial inductance theory. An example with the procedure to calculate coupling coefficient of two magnetic resonant coils is presented. © 2010 IEEE.link_to_subscribed_fulltex

Disc location dependence of the proteoglycan (PG) T2 value in human lumbar intervertebral disc

Traditional Poster Session - Musculoskeleta: Muscle: no. 1233This study explored the capability of proteoglycan (PG) T2 value as a marker of the intervertebral disc degeneration (IVDD). PG T2 and water T2 value, as well as PG/water ratio were measured on 4 different disc levels of lumbar spine. The PG T2 value showed a slightly increasing trend from the upper disc level to the lower disc level. The significant difference of PG T2 value was found between disc L3-4 and disc L4-5 while the water T2 and PG/water ratio showed no statistical significant change between disc levels. Our result suggests the increased PG T2 value could be the reflection of disc degeneration taken place. Demonstrated by this preliminary study, the PG T2 measurement on clinical scanner is highly feasible and the PG T2 value might be a potential marker for the early detection of disc degeneration.link_to_OA_fulltex

Nanomechanical measurement of adhesion and migration of leukemia cells with phorbol 12-myristate 13-acetate treatment

Zhuo Long Zhou,1 Jing Ma,2 Ming-Hui Tong,1 Barbara Pui Chan,1 Alice Sze Tsai Wong,2 Alfonso Hing Wan Ngan1 1Department of Mechanical Engineering, 2School of Biological Sciences, University of Hong Kong, Hong Kong, People’s Republic of China Abstract: The adhesion and traction behavior of leukemia cells in their microenvironment is directly linked to their migration, which is a prime issue affecting the release of cancer cells from the bone marrow and hence metastasis. In assessing the effectiveness of phorbol 12-myristate 13-acetate (PMA) treatment, the conventional batch-cell transwell-migration assay may not indicate the intrinsic effect of the treatment on migration, since the treatment may also affect other cellular behavior, such as proliferation or death. In this study, the pN-level adhesion and traction forces between single leukemia cells and their microenvironment were directly measured using optical tweezers and traction-force microscopy. The effects of PMA on K562 and THP1 leukemia cells were studied, and the results showed that PMA treatment significantly increased cell adhesion with extracellular matrix proteins, bone marrow stromal cells, and human fibroblasts. PMA treatment also significantly increased the traction of THP1 cells on bovine serum albumin proteins, although the effect on K562 cells was insignificant. Western blots showed an increased expression of E-cadherin and vimentin proteins after the leukemia cells were treated with PMA. The study suggests that PMA upregulates adhesion and thus suppresses the migration of both K562 and THP1 cells in their microenvironment. The ability of optical tweezers and traction-force microscopy to measure directly pN-level cell–protein or cell–cell contact was also demonstrated. Keywords: adhesion, migration, cell-to-cell contact, optical trapping, traction-force microscopy, protein micropillar matri