Relocation of inadequate resection margins in the wound bed during oral cavity oncological surgery: A feasibility study

Background: Specimen-driven intraoperative assessment of the resection margins provides immediate feedback if an additional excision is needed. However, relocation of an inadequate margin in the wound bed has shown to be difficult. The objective of this study is to assess a reliable method for accurate relocation of inadequate tumor resection margins in the wound bed after intraoperative assessment of the specimen. Methods: During oral cavity cancer surgery, the surgeon placed numbered tags on both sides of the resection line in a pair-wise manner. After resection, one tag of each pair remained on the specimen and the other tag in the wound bed. Upon detection of an inadequate margin in the specimen, the tags were used to relocate this margin in the wound bed. Results: The method was applied during 80 resections for oral cavity cancer. In 31 resections an inadequate margin was detected, and based on the paired tagging an accurate additional resection was achieved. Conclusion: Paired tagging facilitates a reliable relocation of inadequate margins, enabling an accurate additional resection during the initial surgery

Intraoperative Assessment of the Resection Specimen Facilitates Achievement of Adequate Margins in Oral Carcinoma

Background: Inadequate resection margins in oral cavity squamous cell carcinoma have an adverse effect on patient outcome. Intraoperative assessment provides immediate feedback enabling the surgeon to achieve adequate resection margins. The goal of this study was to evaluate the value of specimen-driven intraoperative assessment by comparing the margin status in the period before and the period after the introduction of specimen-driven assessment as a standard of care (period 2010–2012 vs period 2013–2017). Methods: A cohort of patients surgically treated for oral squamous cell carcinoma at the Erasmus MC Cancer Institute, Rotterdam, between 2010–2012 was studied retrospectively and compared to results of a prospectively collected cohort between 2013–2017. The frequency, type and results of intraoperative assessment of resection margins were analyzed. Results: One hundred seventy-four patients were included from 2010–2012, 241 patients were included from 2013–2017. An increase in the frequency of specimen-driven assessment was seen between the two periods, from 5% in 2010–2012 to 34% in 2013–2017. When performing specimen-driven assessment, 16% tumor-positive resection margins were found in 2013–2017, compared to 43% tumor-positive resection margins overall in 2010–2012. We found a significant reduction of inadequate resection margins for specimen-driven intraoperative assessment (p < 0.001). Also, tumor recurrence significantly decreased, and dise

Regulation of cell fate and meristem maintenance in Arabidopsis root development

Asymmetric cell division is an essential and universal mechanism for generating diversity and pattern in multicellular organisms. Divisions generating daughter cells different in size, shape, identity and function are fundamental to many developmental processes including fate specification, tissue patterning and self-renewal. It is hypothesized that the angiosperm root meristem has evolved from the shoot apical meristem. Presumably, this is the outcome of the plants adaptation to changing environmental conditions. Accordingly, key gene network motifs present in the shoot have been found to be important in the development and regulation of the root meristem, such as peptide ligands and their receptors. In this thesis Arabidopsis root patterning and meristem maintenance has been investigated using forward and reverse genetics approaches. I describe the identification and analysis of SCHIZORIZA (SCZ). SCZ encodes a member of the family of heat shock transcription factors, albeit one that appears to be recruited for development instead of stress signaling. The pleiotropic effects of the scz mutation define the existence of a novel mechanism for patterning cell identity in the Arabidopsis root. SCZ acts in a parallel pathway with SHR/SCR to specify the root stem cell niche in the early embryo. Overexpression of CLE family peptides restricts the size of both the shoot and root meristem, suggesting that signaling pathways involved in shoot and root meristem maintenance are conserved. An activation tagging screen was performed on transgenic plants ectopically expressing CLE19 in the root meristem, aimed to identify new components of a root CLE signaling pathway. A recessive mutant, sol3, was isolated, which suppresses the CLE19 overexpression phenotype. SOL3 has a dual role in the root controlling growth and formative cell divisions. Using a reverse genetics approach I established and analyzed a collection of homozygous T-DNA insertion lines for 69 leucine-rich repeat receptor-like kinases (LRR RLKs) for developmental and conditional phenotypes. Possibly due to genetic redundancy the functional loss-of-function studies revealed developmental phenotypes for only one mutant line, rlk902. T-DNA insertion mutants assayed for their response after exposure to environmental, hormonal/chemical and abiotic stress, reveal several novel conditional functions for a number of RLK genes. rlk902 mutants show both reduced root growth and resistance to the oomycete pathogen Hyaloperonospora arabidopsidis. These phenotypes are not caused by RLK902 inactivation but are linked to the T-DNA insertion. Microarray analysis revealed downregulated gene expression over an 84 kb region upstream of and including RLK902 in rlk902, putatively encompassing the causal gene(s). The identification of SCZ as factor involved in tissue specification and cell fate segregation provides a basis for future research into mechanisms of asymmetric division. Work on CLE ligand signaling identified SOL3 as a factor controlling root growth and formative divisions and the LRR RLK reverse genetics indicated the existence of extensive cross talk and signal integration among different RLK signaling pathways in the Arabidopsis root. A challenge for the future will be to integrate these results with signaling networks for root patterning and growth

Building a plant: cell fate specification in the early Arabidopsis embryo

Embryogenesis is the beginning of plant development, yet the cell fate decisions and patterning steps that occur during this time are reiterated during development to build the post-embryonic architecture. In Arabidopsis, embryogenesis follows a simple and predictable pattern, making it an ideal model with which to understand how cellular and tissue developmental processes are controlled. Here, we review the early stages of Arabidopsis embryogenesis, focusing on the globular stage, during which time stem cells are first specified and all major tissues obtain their identities. We discuss four different aspects of development: the formation of outer versus inner layers; the specification of vascular and ground tissues; the determination of shoot and root domains; and the establishment of the first stem cells

A plant U-box protein, PUB4, regulates asymmetric cell division and cell proliferation in the root meristem

The root meristem (RM) is a fundamental structure that is responsible for postembryonic root growth. The RM contains the quiescent center (QC), stem cells and frequently dividing meristematic cells, in which the timing and the frequency of cell division are tightly regulated. In Arabidopsis thaliana, several gain-of-function analyses have demonstrated that peptide ligands of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION-RELATED (CLE) family are important for maintaining RM size. Here, we demonstrate that a plant U-box E3 ubiquitin ligase, PUB4, is a novel downstream component of CLV3/CLE signaling in the RM. Mutations in PUB4 reduced the inhibitory effect of exogenous CLV3/CLE peptide on root cell proliferation and columella stem cell maintenance. Moreover, pub4 mutants grown without exogenous CLV3/CLE peptide exhibited characteristic phenotypes in the RM, such as enhanced root growth, increased number of cortex/endodermis stem cells and decreased number of columella layers. Our phenotypic and gene expression analyses indicated that PUB4 promotes expression of a cell cycle regulatory gene, CYCD6;1, and regulates formative periclinal asymmetric cell divisions in endodermis and cortex/endodermis initial daughters. These data suggest that PUB4 functions as a global regulator of cell proliferation and the timing of asymmetric cell division that are important for final root architecture

Embryogenesis: Pattern Formation from a Single Cell

During embryogenesis a single cell gives rise to a functional multicellular organism. In higher plants, as in many other multicellular systems, essential architectural features, such as body axes and major tissue layers are established early in embryogenesis and serve as a positional framework for subsequent pattern elaboration. In Arabidopsis, the apicalbasal axis and the radial pattern of tissues wrapped around it are already recognizable in young embryos of only about a hundred cells in size. This early axial pattern seems to provide a coordinate system for the embryonic initiation of shoot and root. Findings from genetic studies in Arabidopsis are revealing molecular mechanisms underlying the initial establishment of the axial core pattern and its subsequent elaboration into functional shoots and roots. The genetic programs operating in the early embryo organize functional cell patterns rapidly and reproducibly from minimal cell numbers. Understanding their molecular details could therefore greatly expand our ability to generate plant body patterns de novo, with important implications for plant breeding and biotechnology

CMS Physics Technical Design Report: Addendum on High Density QCD with Heavy Ions

This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies $\sqrt{s_{NN}}= 5.5\,{\rm TeV}$ , will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction \u2014 Quantum Chromodynamics (QCD) \u2014 in extreme conditions of temperature, density and parton momentum fraction (low- x ). This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include "bulk" observables, (charged hadron multiplicity, low p T inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high p T hadrons which yield "tomographic" information of the hottest and densest phases of the reaction