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Plant-Based Adjunct Therapy for Tuberculosis
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Lydia Gibango, Anna-Mari Reid, Jonathan L. Seaman, Namrita Lall
The duration of the dormancy is dependent on the strength of the host’s immune system and responses when the immune system is compromised in any way due to several factors such as aging, intake of immunosuppressant drugs or via infection of immune-weakening pathogens such as human immunodeficiency virus (HIV) (Daniel, 2006). Replication of the internalized M. tuberculosis cells results in bacteria-laden immune cells that may potentially cross the alveolar barrier and may disseminate systemically and manifest as various forms of extrapulmonary tuberculosis (Ahmad, 2011). Since dendritic cells are migratory cells, it is thought that they may play a role in dissemination (Smith, 2003).
Diseases of the Hair
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Rodney Sinclair, Wei-Liang Koh
Course: PPB usually progress in a slow manner over the years before activity ends spontaneously. Some patients may have periods of activity interspersed with periods of dormancy before the disease burns out.
Sustainable Production of Aquatic and Wetland Plants
Published in Namrita Lall, Aquatic Plants, 2020
Numerous species remain dormant (even after overcoming primary dormancy) unless ideal environmental conditions necessary to overcome secondary dormancy are present. This is a mechanism that allows germination to be scattered through time, enhancing the genetic pool of the seed bank and improving a species’ chance of persistence under changing climatic conditions. Numerous mechanisms of dormancy exist from physical to physiological and morphological dormancies. Particular conditions are required to overcome dormancy. These conditions often imitate natural processes. For example, mechanical scarification imitates trampling/pecking to overcome physical dormancy, and cold conditions imitates overwintering to facilitate physiological development and overcome physiological dormancy, while time is necessary to complete the development of naturally underdeveloped embryos of morphologically dormant seed (Finch-Savage and Leubner-Metzger 2006). It is well known that before germination is initiated in ideal conditions to avoid secondary dormancy, certain conditions or treatments are necessary to overcome primary dormancy. The selected dormancy mechanism is quite species-specific. Since it is generally difficult to predict the presence or type of dormancy based on physical characteristics of the seed, a few strategies are commonly used to overcome primary dormancy. Dormancy breaking treatments include scarification, imbibition with water, smoke solution, gibberellic acid, and/or cold or warm treatments (Finch-Savage and Leubner-Metzger 2006).
Pituitary carcinomas: review of the current literature and report of atypical case
Published in British Journal of Neurosurgery, 2020
Alexandre B. Todeschini, André Beer-Furlan, Alaa S. Montaser, Ali O. Jamshidi, Luma Ghalib, Jesus A. Chavez, Norman L. Lehman, Daniel M. Prevedello
Cancer dormancy refers to the asymptomatic period of time after initial treatment in which residual viable cells persist in the body in a latent state retaining the potential to initiate growth.37 There are 2 mechanisms to explain tumour dormancy: (1) growth arrest from lack of an adequate vascular supply and (2) cell development arrest in the G0/G1 phase due to the absence of adequate extrinsic or intrinsic signals from the cells’ micro-environment.38,39,41 The escape from dormancy is poorly understood. One of the theories to explain this ‘awakening’ is a sudden peak of angiogenic factors, such as fibroblast growth factor (FGF) or vascular endothelial growth factor (VEGF), which can alter the micro-environment of the dormant cells and provide the necessary vascular supply.42 The dormancy period may also be required for a cell to develop the required random mutations that leads to a malignant or aggressive disease. Currently, research in cancer dormancy mechanisms have not led to a clinical application, but future studies may possibly take advantage of this phenomenon to control cases of disseminated cancer, by artificially returning the cells to a dormant state, or to identify and eradicate these dormant cells, preventing late metastasis.38
Research progress on therapeutic targeting of quiescent cancer cells
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Jinhua Zhang, Jing Si, Lu Gan, Cuixia Di, Yi Xie, Chao Sun, Hongyan Li, Menghuan Guo, Hong Zhang
Moreover, dormant colorectal cancer cells are reported to respond to itraconazole, which suppresses the Wnt pathway through non-canonical Hedgehog signaling. Itraconazole treatment initially caused a proliferative burst, forcing dormant cells to cycle briefly and subsequently enter irreversible G1 cell cycle arrest and senescence [31,48]. Furthermore, tubeimoside-1 potently suppressed the growth of human prostate cancer cells via inducing oxidative stress-mediated apoptosis and G0/G1 phase arrest [49]. Arctigenin, the active component of burdock root, enhanced p27Kip1 protein levels through inhibition of Akt and stimulation of FOXO3a activity, in turn, suppressing CDK2 kinase activity and finally inducing overall inhibition of HSC proliferation and G0/G1 phase arrest [50]. Altogether, our findings suggest that dormancy can be effectively sustained through inhibition of proliferative signaling, activation of dormant pathways or delivering the components of dormant niches.
Hepatic micrometastases outside macrometastases are present in all patients with ileal neuroendocrine primary tumour at the time of liver resection
Published in Scandinavian Journal of Gastroenterology, 2019
Reidar Fossmark, Tine M. Balto, Tom C. Martinsen, Jon E. Grønbech, Bjørn Munkvold, Patricia G. Mjønes, Helge L. Waldum
The observed dormancy of NETs may in part be explained by a low rate of proliferation, often with a Ki67 < 1%, and it may take many years before micrometastases become visible (>3 mm) at cross sectional imaging. However, also in other types of cancer there may be years to decades of latency before disease recurrence can be detected. The concept of cancer dormancy has developed over time [18] and although its mechanisms are incompletely understood [19], cellular dormancy, angiogenic dormancy as well as immunosurveillance have been suggested to be important. A better understanding of dormancy as a phenomenon could prove to be of particular importance for NET patients. Immunological destruction of smaller groups of cells have been described in other types of cancer [20] and one could speculate that micrometastases from NETs could be eliminated by this mechanism. However, avoiding immune destruction is considered a hallmark of cancer [21] and the clinical course of NET patient cohorts, where recurrence most often occurs, suggests that the immune system by itself does not eradicate all NET cells. One could further speculate that highly differentiated NET cells express markers that initiate immunological destruction less frequently than many other cancers.