Late side effects of radiation treatment for head and neck cancer

Itzhak Brook 대한방사선종양학회 2020 Radiation Oncology Journal Vol.38 No.2

Patients undergoing radiation therapy for head and neck cancer (HNC) experience significant early and long-term side effects. The likelihood and severity of complications depends on a number of factors, including the total dose of radiation delivered, over what time it was delivered and what parts of the head and neck received radiation. Late side effects include: permanent loss of saliva; osteoradionecrosis; radiation recall myositis, pharyngoesophageal stenosis; dental caries; oral cavity necrosis; fibrosis; impaired wound healing; skin changes and skin cancer; lymphedema; hypothyroidism, hyperparathyroidism, lightheadedness, dizziness and headaches; secondary cancer; and eye, ear, neurological and neck structures damage. Patients who undergo radiotherapy for nasopharyngeal carcinoma tend to suffer from chronic sinusitis. These side effects present difficult challenges to the patients and their caregivers and require life-long strategies to alleviate their deleterious effect on basic life functions and on the quality of life. This review presents these side effects and their management.

Neonatal tetanus

Itzhak Brook 대한소아응급의학회 2021 대한소아응급의학회지 Vol.8 No.1

Neonatal tetanus, also known as tetanus neonatorum, occurs in young infants of inadequately immunized mothers. It is a kind of generalized tetanus that is exhibited mainly by prevention of the release of the inhibitory neurotransmitters (i.e., disinhibition) and is initiated by tetanospasmin, an exotoxin created by Clostridium tetani. Contamination of the umbilical cord stump is the main cause. The typical, early manifestations are weakness and lack of ability to suck, continuing within hours to trismus, risus sardonicus, and ultimately generalized tetanic spasm, rigidity, and opisthotonus. Without treatment, neonatal tetanus has a poor outcome with a mortality rate above 90%. Mortality can result from asphyxia due to the spasm and hypersympathetic state. The managing goals are to neutralize its toxin, eradicate C. tetani, care for wound, and offer supportive care, such as mechanical ventilation, parenteral nutrition, sedation, neuromuscular blockade, and management of autonomic dysfunction.

EXPORT DIVERSIFICATION AND EXPORT PERFORMANCE: A CONTINGENCY- AND RESOURCE DEPENDENCY-BASED ASSESSMENT

Itzhak Gnizy,John W. Cadogan,Jo?o S. Oliveira,Asmat-Nizam Abdul-Talib 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07

Export diversification – the extent to which the firm seizes export sales opportunities across different nations and/or geographic regions – is a critical element of export marketing strategy. Yet, knowledge of the export performance consequences of export diversification is lacking. Underpinned by contingency and resource dependence theories, we examine the export diversification-export performance relationship as well as critical contingencies of this link. Based on a sample of UK exporters we find that firms gain the highest export performance benefits when they simultaneously increase national and regional export diversification. Our results also show that the export diversification-export performance link is weaker when firms operate in markets that are very in dynamism. Additionally, the relationship between export diversification and performance is stronger when both resource sharing and interfunctional coordination are high. Such contextual factors provide a better understanding of the diversification-performance relationship.

INTERNATIONAL MARKETING STRATEGY PLANNING AND PERFORMANCE: THE ROLES OF MARKET SENSING AND TOLERANCE FOR FAILURE

Itzhak Gnizy,Yoel Asseraf,Moty Amar 글로벌지식마케팅경영학회 2023 Global Marketing Conference Vol.2023 No.07

Assertions in current academic research and practical discourse that promote agility reduce the importance or prominence given to organizational strategic planning. While firms today are required to become agile and thus quickly and timely respond to emerging market challenges, the strategic planning process is perceived as rigid, slow, and somehow obsolete and may contradict agility. These present practitioners with a dilemma regarding the relevance of planning in this era. This study examines the pertinence of strategy planning in this agile age and its effect on firms’ business performance. In addition, since the environment in which firms operate play a significant role in determining strategies, when maintaining strategic planning, organizations need to consider internal and external factors that may change the effect of planning on performance. Hence, the study also explores market scanning (an external condition) and fault tolerance climate (an internal condition) under which the relationship planning-performance varies. Based on a quantitative research, data from organizations, and insights from fit-as-moderation approach, a conceptual model and research hypotheses are designed and tested. Common and acceptable analysis methods were employed to test the hypotheses. Initial findings indicate that strategy planning should not be deemphasized in contemporary days since it is associated with better financial (e.g., sales growth) and nonfinancial (e.g., new customer acquirement) outcomes. Additionally, performance consequences of planning are dependent on firm external and internal conditions. While the positive planning-performance relationship is associated with higher levels of market sensing, it is negatively associated with higher levels of fault tolerance. The findings have well-timed theoretical and practical implications for the business and strategy literature. Managers considering the necessity of planning strategies should recognize its relevance and take into account contingencies examined in this research.

Inhomogeneous distribution of water droplets in cloud turbulence

Fouxon, Itzhak,Park, Yongnam,Harduf, Roei,Lee, Changhoon American Physical Society 2015 Physical review. E, Statistical, nonlinear, and so Vol.92 No.3

Direct Numerical Simulation of Droplets Sedimenting in Cloud Turbulence

Changhoon Lee,Yongnam Park,Itzhak Fouxon 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.10

In Vitro Real-Time Interactions of Cranberry Constituents with Immobilized Fructosyltransferase

Mark Feldman,Ervin I. Weiss,Itzhak Ofek,Moshe Shemesh,Doron Steinberg 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.5

Cranberry has been proposed as an anti-biofilm agent that does not kill bacteria, but rather prevents the pathogen from survival in the host. This can be achieved by inhibiting the function of virulent factors essential for the pathogen to persist in a host environment. The oral bacterial enzyme fructosyltransferase (FTF) plays an important role in the pathogenesis of dental diseases. The real-time interaction of cranberry nondialyzable material (NDM) with immobilized FTF was investigated using the surface plasmon resonance (SPR) technique. To determine its binding efficiency, NDM at concentrations between 0μg/mL and 200μg/mL was applied onto the immobilized FTF. The effect of NDM or other polyphenols, myricetin, and epicatechin on FTF enzymatic activity was evaluated by applying the above compounds and sucrose onto immobilized FTF. Salivary amylase was applied with NDM onto immobilized FTF to explore the effect on NDM–FTF interaction. Our results show that NDM firmly attaches to immobilized FTF in a dose-dependent manner, whereas the presence of salivary amylase reduced this binding interaction. Using nonlinear regression we calculated that the affinity constant of NDM applied alone (106 M−1) was fivefold higher than NDM in the presence of amylase (0.2×106 M−1). At 200μg/mL, NDM, introduced together with sucrose, inhibited the activity of immobilized FTF by 63% within minutes, in comparison with the control (sucrose alone). The effect of NDM was sustained even after it was washed off the immobilized FTF. Myricetin also strongly inhibited FTF activity, whereas epicatechin was less effective. The real-time SPR observation suggests that one of the anti-biofilm modes of action of NDM is an immediate and irreversible inhibitory effect on the activity of immobilized FTF, which is due to a strong binding affinity to the immobilized enzyme

Neural stem cells may be uniquely suited for combined gene therapy and cell replacement: Evidence from engraftment of Neurotrophin-3-expressing stem cells in hypoxic–ischemic brain injury

Park, Kook In,Himes, B. Timothy,Stieg, Philip E.,Tessler, Alan,Fischer, Itzhak,Snyder, Evan Y. Elsevier 2006 Experimental neurology Vol.199 No.1

<P><B>Abstract</B></P><P>Previously, we reported that, when clonal neural stem cells (NSCs) were transplanted into brains of postnatal mice subjected to unilateral hypoxic–ischemic (HI) injury (optimally 3–7 days following infarction), donor-derived cells homed preferentially (from even distant locations) to and integrated extensively within the large ischemic areas that spanned the hemisphere. A subpopulation of NSCs and host cells, particularly in the penumbra, “shifted” their differentiation towards neurons and oligodendrocytes, the cell types typically damaged following asphyxia and least likely to regenerate spontaneously and in sufficient quantity in the “post-developmental” CNS. That no neurons and few oligodendrocytes were generated from the NSCs in intact postnatal cortex suggested that novel signals are transiently elaborated following HI to which NSCs might respond. The proportion of “replacement” neurons was ∼5%. Neurotrophin-3 (NT-3) is known to play a role in inducing neuronal differentiation during development and perhaps following injury. We demonstrated that NSCs express functional TrkC receptors. Furthermore, the donor cells continued to express a foreign reporter transgene robustly within the damaged brain. Therefore, it appeared feasible that neuronal differentiation of exogenous NSCs (as well as endogenous progenitors) might be enhanced if donor NSCs were engineered prior to transplantation to (over)express a bioactive gene such as NT-3. A subclone of NSCs transduced with a retrovirus encoding NT-3 (yielding >90% neurons in vitro) was implanted into unilaterally asphyxiated postnatal day 7 mouse brain (emulating one of the common causes of cerebral palsy). The subclone expressed NT-3 efficiently in vivo. The proportion of NSC-derived neurons increased to ∼20% in the infarction cavity and >80% in the penumbra. The neurons variously differentiated further into cholinergic, GABAergic, or glutamatergic subtypes, appropriate to the cortex. Donor-derived glia were rare, and astroglial scarring was blunted. NT-3 likely functioned not only on donor cells in an autocrine/paracrine fashion but also on host cells to enhance neuronal differentiation of both. Taken together, these observations suggest (1) the feasibility of taking a fundamental biological response to injury and augmenting it for repair purposes and (2) the potential use of migratory NSCs in some degenerative conditions for simultaneous combined gene therapy and cell replacement during the same procedure in the same recipient using the same cell (a unique property of cells with stem-like attributes).</P>

Age-dependent root canal instrumentation techniques: a comprehensive narrative review

Solomonov, Michael,Kim, Hyeon-Cheol,Hadad, Avi,Levy, Dan Henry,Itzhak, Joe Ben,Levinson, Oleg,Azizi, Hadas The Korean Academy of Conservative Dentistry 2020 Restorative Dentistry & Endodontics Vol.45 No.1

The aim of this article was to review age-dependent clinical recommendations for appropriate root canal instrumentation techniques. A comprehensive narrative review of canal morphology, the structural characteristics of dentin, and endodontic outcomes at different ages was undertaken instead of a systematic review. An electronic literature search was carried out, including the Medline (Ovid), PubMed, and Web of Science databases. The searches used controlled vocabulary and free-text terms, as follows: 'age-related root canal treatment,' 'age-related instrumentation,' 'age-related chemo-mechanical preparation,' 'age-related endodontic clinical recommendations,' 'root canal instrumentation at different ages,' 'geriatric root canal treatment,' and 'pediatric root canal treatment.' Due to the lack of literature with practical age-based clinical recommendations for an appropriate root canal instrumentation technique, a narrative review was conducted to suggest a clinical algorithm for choosing the most appropriate instrumentation technique during root canal treatment. Based on the evidence found through the narrative review, an age-related clinical algorithm for choosing appropriate instrumentation during root canal treatment was proposed. Age affects the morphology of the root canal system and the structural characteristics of dentin. The clinician's awareness of root canal morphology and dentin characteristics can influence the choice of instruments for root canal treatment.

Age-dependent root canal instrumentation techniques: a comprehensive narrative review

Solomonov Michael,Kim Hyeon-Cheol,Hadad Avi,Levy Dan Henry,Ben Itzhak Joe,Levinson Oleg,Azizi Hadas 대한치과보존학회 2020 Restorative Dentistry & Endodontics Vol.45 No.2

The aim of this article was to review age-dependent clinical recommendations for appropriate root canal instrumentation techniques. A comprehensive narrative review of canal morphology, the structural characteristics of dentin, and endodontic outcomes at different ages was undertaken instead of a systematic review. An electronic literature search was carried out, including the Medline (Ovid), PubMed, and Web of Science databases. The searches used controlled vocabulary and free-text terms, as follows: ‘age-related root canal treatment,’ ‘age-related instrumentation,’ ‘age-related chemo-mechanical preparation,’ ‘age-related endodontic clinical recommendations,’ ‘root canal instrumentation at different ages,’ ‘geriatric root canal treatment,’ and ‘pediatric root canal treatment.’ Due to the lack of literature with practical age-based clinical recommendations for an appropriate root canal instrumentation technique, a narrative review was conducted to suggest a clinical algorithm for choosing the most appropriate instrumentation technique during root canal treatment. Based on the evidence found through the narrative review, an age-related clinical algorithm for choosing appropriate instrumentation during root canal treatment was proposed. Age affects the morphology of the root canal system and the structural characteristics of dentin. The clinician’s awareness of root canal morphology and dentin characteristics can influence the choice of instruments for root canal treatment.