Environmental and Cytotoxicity Risks of Graphene Family Nanomaterials
Suresh C. Pillai, Yvonne Lang in Toxicity of Nanomaterials, 2019
The direct interaction of GO with protein receptors and consequential activation of the B-cell lymphoma-2 (Bcl-2) educed ROS-dependent apoptosis. Carboxylate GO bound to protein receptors which prompted the communication of a submissive apoptosis signal to nuclear DNA, this time actuating a ROS-independent route. On the other hand, polyethylenimine-modified GO triggered apoptosis by means of severe T lymphocyte damage (Ding et al., 2014). Autophagy or non-apoptotic cell death is the self-destruction of damaged cells prior to new cell formation. Under stress conditions autophagy processes surge but activation is first required in the form of Beclin 1-containing autophagosomes, various autophagy-associated proteins, and microtubule-related proteins such as light chain 3 and p62 (Levine et al., 2011). The accumulation of autophagosomes has been correlated with an exposure to a variety of NMs (Chen et al., 2015; Halamoda Kenzaoui et al., 2012; Hussain and Garantziotis, 2013). What is more, autophagy processes are capable of removing extracellular organisms and dismantle the organisms in the cytosol (Chen et al., 2014). Studies demonstrated that both GO and GQDs evoked autophagosome accumulation, the adaption of LC3-I to LC3-II and inhibition of autophagic substrate p62 protein degradation (Markovic et al., 2012; Wan et al., 2013). In addition, GO instantaneously activated TLR4 and TLR9 reactions in macrophages (Chen et al., 2012a; Yue et al., 2012) and colon carcinoma cells (Chen et al., 2014). Thus, the route of autophagy processes is associated with phagocytosis by TLR macrophage signalling (Chen et al., 2014; Sanjuan et al., 2007). Necrosis is a form of cell death induced by disease or injury. Elevated doses of graphene have previously been reported to provoke apoptosis and necrosis (Lalwani et al., 2016; Li et al., 2012b). GO too induced macrophagic necrosis through TLR4 signalling activation (Qu et al., 2013).
Bacteria and Bioactive Peptides
Prakash Srinivasan Timiri Shanmugam in Understanding Cancer Therapies, 2018
Later studies used pathogenic species of the anaerobic clostridia for their proliferation within the necrotic (anaerobic) regions of tumors in experimental animals as compared to normal tissues. The experiments caused regression of tumors but showed acute toxicity as well as death of most of the experimented animals (Minton 2003). These drastic outcomes shifted to the use of a nonpathogenic strain of Clostridium, which showed its potentiality to colonize anaerobic parts of the tumor after intravenous administration, but the outcome was not satisfactory in terms of tumor regression (Carey et al. 1967). Anaerobic bacterial species such as Clostridium novyi demonstrated significant antitumor activity but showed lethal effects on experimental animals. The attenuated C. novyi-NT exhibited significant antitumor effects but also showed severe toxicity. The use of obligate anaerobic bacteria or facultative anaerobic as alternative cancer therapeutics has been followed over more than a century due to the insights gained over time on host–bacteria interactions, genome information for many of the bacteria employed, and especially efficient molecular tools. A number of bacterial species have proven their tumor therapeutic effects in murine model systems. The lack of effectiveness of these bacterial therapies encouraged continuous efforts to identify other novel bacterial strains as anticancer therapeutic tools. Pathogens frequently cause cell death in infected tissues. Apoptosis, or programmed cell death, is the principal physiological process for eliminating unnecessary cells during embryogenesis, in the development and regulation of the immune system, and during normal cell turnover in many tissues (Marsden et al. 2002). Necrosis is usually associated with tissue injury from an interruption in the vascular supply, decreased oxygenation, or various noxious environmental factors (Majno and Joris 1995). Bifidobacterium breve and Bifidobacterium adolescentis have also been shown to target model tumors and act as reliable gene therapy vectors (Hidaka et al. 2007). A number of facultative bacteria such as Escherichia coli, Shigella flexneri, Vibrio cholera, and Listeria monocytogenes have been employed for their potential role in bacteria-mediated tumor therapy. The facultative anaerobes can colonize hypoxic and necrotic areas as well as viable cells in tumors because they are not restricted to hypoxic environments (Leschner and Weiss 2010). S. flexneri, V. cholera, and L. monocytogenes showed colonization in various model tumors in mice but exhibited a lack of tumoricidal activity (Yu et al. 2008). The findings, therefore, suggest that several bacteria are able to colonize tumors, but possessing antitumor activity is still limited. E. coli DH5α has been shown to grow in various subcutaneous tumors of nude mice, and it is able to grow in small metastatic nodules. Likewise, E. coli strain TOP10, strain CFT073, the enteroinvasive strain 4608–58, and Nissle 1917 have been shown to colonize solid tumors (Stritzker et al. 2007).
The Hand
Louis Solomon, David Warwick, Selvadurai Nayagam in Apley and Solomon's Concise System of Orthopaedics and Trauma, 2014
Acute inflammation and suppuration in small closed compartments (e.g. the pulp space or tendon sheath) may cause an increase in pressure to levels at which the local blood supply is threatened. In neglected cases tissue necrosis is an imminent risk. Even if this does not occur, the patient may end up with a stiff and useless hand unless the infection is rapidly brought under control.
Treatment of glabella skin necrosis following injection of hyaluronic acid filler using platelet-rich plasma
Published in Journal of Cosmetic and Laser Therapy, 2016
Boo Kyoung Kang, In Jung Kang, Ki Heon Jeong, Min Kyung Shin
Hyaluronic acid (HA) fillers have been widely used for soft-tissue augmentation. However, there can be various complications following HA filler injection. Skin necrosis is rare but one of the most disastrous side effects that, if not treated promptly and effectively, can result in permanent and potentially disfiguring scarring. Thus, early proper management is important. Herein we report a patient who experienced tissue necrosis of the glabellar area after receiving filler injections that was successfully treated using platelet-rich plasma and provide full follow-up clinical photographs.
The Usage of a Conjunctival Flap to Improve Retention of Boston Type 1 Keratoprosthesis in Severe Ocular Surface Disease
Published in Ocular Immunology and Inflammation, 2016
Allen O. Eghrari, Sumayya Ahmad, Pradeep Ramulu, Nicholas T. Iliff, Esen Karamursel Akpek
Purpose: The Boston keratoprostheses type 1 devices (KPro) are utilized in cases unfavorable to penetrating keratoplasty. The prognosis remains guarded in cases of ocular surface disease due to risk of tissue necrosis. We describe a novel surgical approach using a conjunctival flap with a delayed opening to improve retention. Methods: In three patients with advanced cicatrizing conjunctivitis, a Type 1 keratoprosthesis was stabilized using a full tarsal conjunctival flap. Three months postoperatively, an opening was created in the flap overlying the optical portion of the device. Results: All patients had no device related complications over a mean follow-up period of 17.7 months (range 15-21 months) and vision remained excellent at better than 20/200 for all patients. Conclusions: Utilization of a tarsal flap either primarily as part of a two stage modified technique or secondarily in cases of tissue necrosis and impending device extrusion might maximize retention of the type 1 KPro.
Regression of a Paraganglioma Tumor of the Orbit
Published in Orbit, 2015
Robert H. Hill, Sean M. Platt, Thomas A. Bersani, Ann Barker-Griffith, Kenneth B. Strumpf
Purpose: To describe a clinical case of an orbital paraganglioma that displayed regression after biopsy alone. Methods: Case report. Results: A 75-year-old female was examined for a right orbital tumor suspected to be metastatic breast carcinoma. An orbital biopsy was performed with significant hemorrhage encountered requiring extensive cautery. There was apparent clinical regression of the tumor with no signs of proptosis or eye movement restriction two years after this patient’s biopsy. Histology was consistent with paraganglioma (glomus tumor). Conclusion: Although we cannot rule out spontaneous regression of this unique tumor, we postulate that tissue necrosis caused by the use of cautery induced regression. Unless encapsulated and easily accessible, we suggest that the best management of this rare tumor is that of observation after being found negative for malignancy by biopsy given their propensity for slow progression and in rare cases, regression.
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