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Topic Review
Population Stratification
Population stratification (or population structure) is the presence of a systematic difference in allele frequencies between subpopulations in a population, possibly due to different ancestry, especially in the context of association studies.
  • 1.0K
  • 02 Dec 2022
Topic Review Video Peer Reviewed
Flash Radiotherapy: Innovative Cancer Treatment
Flash radiotherapy (Flash-RT) is an innovative technique used in radiotherapy for cancer treatment because it delivers an extremely high dose of radiation (>40 Gy/s) to the tumour in a very short period of time, typically within a fraction of a second. This ultra-fast delivery of radiation distinguishes Flash-RT from conventional radiotherapy, which typically involves the delivery of radiation over a longer time period, often several minutes. Studies conducted in cell and preclinical models suggested that Flash-RT may spare normal tissues from radiation-related side effects, such as skin toxicity, gastrointestinal complications, and damage to organs-at-risk. This is believed to be due to the unique normal tissue response to the ultra-high dose rate. Nevertheless, while Flash-RT shows promising results in preclinical and early clinical studies, one should note that the technique is still in the early stages of development. This entry provides a comprehensive exploration of the immense potentials of Flash-RT, covering its background, mechanisms, radiation sources, recent experimental findings based on cell and preclinical models, and future prospects. It aims to provide valuable insights into this innovative radiotherapy technology for anyone interested in the subject.
  • 1.0K
  • 27 Jun 2023
Topic Review
Fluoxetine-Mediated CYP2D6 Inhibition
Fluoxetine is still one of the most widely used antidepressants in the world. The drug is extensively metabolized by several cytochrome P450 (CYP450) enzymes and subjected to a myriad of CYP450-mediated drug interactions. In a multidrug regimen, preemptive mitigation of drug–drug interactions requires knowledge of fluoxetine actions on these CYP450 enzymes. The major metabolic pathway of fluoxetine leading to the formation of its active metabolite, norfluoxetine, is mediated by CYP2D6. Fluoxetine and norfluoxetine are strong affinity substrates of CYP2D6 and can inhibit, potentially through various mechanisms, the metabolism of other sensitive CYP2D6 substrates. Remarkably, fluoxetine-mediated CYP2D6 inhibition subsides long after fluoxetine first passes through the liver and even remains long after the discontinuation of the drug. The long-term inhibition of CYP2D6 is likely a result of competitive inhibition due to 1) the strong affinity binding of fluoxetine and norfluoxetine to the enzyme and 2) unbound fluoxetine and norfluoxetine levels circulating in the blood for a long period of time because of their long elimination half-life.
  • 1.0K
  • 04 Feb 2021
Topic Review
Gluten-Free Diet
The gluten-free diet (GFD) has gained increasing popularity in recent years, supported by marketing campaigns, media messages and social networks. Nevertheless, real knowledge of gluten and GF-related implications for health is still poor among the general population. The GFD has also been suggested for non-celiac gluten/wheat sensitivity (NCG/WS), a clinical entity characterized by intestinal and extraintestinal symptoms induced by gluten ingestion in the absence of celiac disease (CD) or wheat allergy (WA).
  • 1.0K
  • 29 Dec 2020
Topic Review
TLR4 and alpha-MSH in allergy
Ocular allergic diseases are frequently seen in ophthalmological clinical practice. Immunological damage is mediated by a local Th2 inflammatory microenvironment, accompanied by changes in circulating cell subsets, with more effector cells and fewer T regulatory cells (Tregs). This study aimed to evaluate the involvement of toll-like receptor 4 (TLR4) and a-melanocyte stimulating hormone (α-MSH) in the immune regulation associated with perennial allergic conjunctivitis (PAC). We performed an Ag-specific stimulation during 72 h of culturing with or without LPS or α-MSH in peripheral blood mononuclear cells (PBMC), analyzing the cell subsets and cytokines induced by the stimuli. We also determined α-MSH in tear samples from healthy donors (HD) or PAC patients. Our findings demonstrate an immunological dysregulation characterized by an increased frequency of CD4+TLR4+ in the PBMC of patients with PAC, compared to HD. Most of these CD4+TLR4+ cells were also CD25+, and when α-MSH was added to the culture, the percentage of CD4+CD25+FoxP3+ increased significantly, while the percentage of CD69+ cells and cytokines IL-4 and IL-6 were significantly decreased. In tears, we found an increased concentration of α-MSH in PAC patients, compared with HD. These findings indicate a novel mechanism involved in controlling ocular allergic diseases, in which α-MSH diminishes the concentration of IL-6 and IL-4, restoring the frequency of Tregs and down-regulating CD4 activation. Moreover, we demonstrate the involvement of CD4+TLR4+ cells, as an effector cell subset, in ocular allergy.
  • 1.0K
  • 27 Oct 2020
Topic Review
Emotion and Memory
Emotion can have a powerful effect on humans and animals. Numerous studies have shown that the most vivid autobiographical memories tend to be of emotional events, which are likely to be recalled more often and with more clarity and detail than neutral events. The activity of emotionally enhanced memory retention can be linked to human evolution; during early development, responsive behavior to environmental events would have progressed as a process of trial and error. Survival depended on behavioral patterns that were repeated or reinforced through life and death situations. Through evolution, this process of learning became genetically embedded in humans and all animal species in what is known as flight or fight instinct. Artificially inducing this instinct through traumatic physical or emotional stimuli essentially creates the same physiological condition that heightens memory retention by exciting neuro-chemical activity affecting areas of the brain responsible for encoding and recalling memory. This memory-enhancing effect of emotion has been demonstrated in many laboratory studies, using stimuli ranging from words to pictures to narrated slide shows, as well as autobiographical memory studies. However, as described below, emotion does not always enhance memory.
  • 999
  • 28 Sep 2022
Topic Review
Research on Meditation
For the purpose of this article, research on meditation concerns research into the psychological and physiological effects of meditation using the scientific method. In recent years, these studies have increasingly involved the use of modern scientific techniques and instruments, such as fMRI and EEG which are able to directly observe brain physiology and neural activity in living subjects, either during the act of meditation itself, or before and after a meditation effort, thus allowing linkages to be established between meditative practice and changes in brain structure or function. Since the 1950s hundreds of studies on meditation have been conducted, but many of the early studies were flawed and thus yielded unreliable results. Contemporary studies have attempted to address many of these flaws with the hope of guiding current research into a more fruitful path. In 2013, researchers at Johns Hopkins, publishing in the Journal of the American Medical Association, identified 47 studies that qualify as well-designed and therefore reliable. Based on these studies, they concluded that there is moderate evidence that meditation reduces anxiety, depression, and pain, but no evidence that meditation is more effective than active treatment (drugs, exercise, other behavioral therapies). A 2017 commentary was similarly mixed. The process of meditation, as well as its effects, is a growing subfield of neurological research. Modern scientific techniques and instruments, such as fMRI and EEG, have been used to study how regular meditation affects individuals by measuring brain and bodily changes.
  • 999
  • 16 Nov 2022
Topic Review
Methodologies and Wearable Devices to Monitor Sleep Dysfunctions
Sleep is crucial for human health from metabolic, mental, emotional, and social points of view; obtaining good sleep in terms of quality and duration is fundamental for maintaining a good life quality. Several systems have been proposed in the scientific literature and on the market to derive metrics used to quantify sleep quality as well as detect sleep disturbances and disorders. In this field, wearable systems have an important role in the discreet, accurate, and long-term detection of biophysical markers useful to determine sleep quality.
  • 998
  • 07 Sep 2022
Topic Review
Advantages and Applications of Total-Body PET Scanning
Total-body positron emission tomography (PET)  scanning can not only image faster than traditional techniques with less administered radioactivity but also perform total-body dynamic acquisition at a longer delayed time point based on its ultrahigh detection sensitivity, enhanced temporal resolution, and long scan range (194 cm). These unique characteristics create several opportunities to improve image quality and can provide a deeper understanding regarding disease detection, diagnosis, staging/restaging, response to treatment, and prognostication. 
  • 998
  • 21 Feb 2022
Topic Review
Sarcoidosis and SARS-CoV-2 Infection
Patients with sarcoidosis are characterized by lung predilection, and in some cases, the imaging features maybe similar to those of the patients with COVID-19 pneumonia. Sarcoidosis is a granulomatous disorder characterized by diffusion of noncaseating and non-necrotizing granulomas, lungs are the most affected site even though no organ is spared.
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  • 04 Mar 2021
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