Tau Phúc - Academia.edu (original) (raw)

Papers by Tau Phúc

Journal of Applied Physics, 2006

ABSTRACT

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since t... more In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

Marine Pollution Bulletin, 2011

We performed stable carbon and nitrogen-guided analyses of biomagnification profiles of arsenic (... more We performed stable carbon and nitrogen-guided analyses of biomagnification profiles of arsenic (As) species, including total As, lipid-soluble As, eight water-soluble As compounds (arsenobetaine (AB), arsenocholine (AC), tetramethylarsonium ion (TETRA), trimethylarsine oxide (TMAO), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), arsenate (As[V]), and arsenite (As[III])), and non-extracted As in a tropical mangrove ecosystem in the Ba Ria Vung Tau, South Vietnam. Arsenobetaine was the predominant As species (65-96% of water-soluble As). Simple linear regression slopes of log-transformed concentrations of total As, As fractions or individual As compounds on stable nitrogen isotopic ratio (d 15 N) values are regarded as indices of biomagnification. In this ecosystem, lipid-soluble As (slope, 0.130) and AB (slope, 0.108) were significantly biomagnified through the food web; total As and other water-soluble As compounds were not. To our knowledge, this is one of the first reports on biomagnification profiles of As compounds from a tropical mangrove ecosystem.

Gynecologic Oncology, 2003

... b , Hiep Phuc Dong CT a , Claes G. Trope&amp;#x27; MD, Ph.D. d , Bjørn Risberg MD, Ph... more ... b , Hiep Phuc Dong CT a , Claes G. Trope&amp;#x27; MD, Ph.D. d , Bjørn Risberg MD, Ph.D. a and Juri Kopolovic MD b. a Department of Pathology, The Norwegian Radium Hospital, Montebello N-0310, Oslo, University of Oslo, Norway. ...

Clinical & Experimental Metastasis, 2003

The aim of this study was to analyze the expression of two laminin receptors, the 67kDa laminin r... more The aim of this study was to analyze the expression of two laminin receptors, the 67kDa laminin receptor (LBP) precursor and the α6 integrin subunit, in effusions and solid tumors of patients diagnosed with serous ovarian carcinoma and to evaluate their predictive role. Eighty-eight effusions and one hundred sixteen primary (= forty-one) and metastatic (= seventy-five) ovarian carcinomas were evaluated for expression of the above-mentioned mRNAs using in situ hybridization (ISH). LBP protein expression was studied in 24 effusions and 43 solid tumors using immunohistochemistry (IHC). α6 integrin subunit protein expression was studied in 27 effusions using flow cytometry (FCM). Expression of LBP mRNA was frequently detected in both carcinoma (92 of 116 cases, 79%) and stromal (79 of 116 cases, 68%) cells in solid tumors. Expression was still higher in cancer cells in effusions (85 of 88 specimens, 96%). In contrast, α6 integrin subunit was less frequently detected in both solid tumors (33 of 116; 28% in carcinoma cells, 23 of 116; 20% in stromal cells) and effusions (36 of 88; 41%). LBP protein expression was found in 19 of 24 (79%) effusions and 40 of 43 (93%) solid tumors, and was higher in effusions of patients who received chemotherapy prior to tapping (P = 0.024). FCM showed protein expression of the α6 integrin subunit in 17 of 27 (63%) effusions. Expression of the α6 integrin subunit mRNA in tumor cells of solid lesions was significantly lower in solid tumors of FIGO stage-IV patients compared to those of patients diagnosed with stage-III-disease (P = 0.004), and its absence predicted significantly shorter overall survival (OS) in univariate analysis (P = 0.018). Absence of α6 integrin subunit protein expression using FCM predicted median OS of 12 months compared to 26 months for patients with tumors expressing the protein, although this finding did not reach significance (P = 0.27). In conclusion, as opposed to previous reports, both mRNA and protein expression of the α6 integrin subunit do not appear to be down-regulated in effusions compared to solid tumors. Loss of α6 integrin subunit mRNA (and possibly protein) expression is a novel prognostic marker in advanced-stage ovarian carcinoma. LBP mRNA and protein expression is independent of that of the α6 integrin subunit in both solid tumors and effusions of serous ovarian carcinoma.