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Topic Review
Nonparametric Limits of Agreement
The assessment of agreement in method comparison and observer variability analysis of quantitative measurements is usually done by the Bland-Altman Limits of Agreement, where the paired differences are implicitly assumed to follow a normal distribution. Whenever this assumption does not hold, the 2.5% and 97.5% percentiles are obtained by quantile estimation. In the literature, empirical quantiles have been used for this purpose. In this simulation study, we applied both sample, subsampling, and kernel quantile estimators as well as other methods for quantile estimation to sample sizes between 30 and 150 and different distributions of the paired differences. The performance of 15 estimators in generating prediction intervals was measured by their respective coverage probability for one newly generated observation. Our results indicated that sample quantile estimators based on one or two order statistics outperformed all the other estimators and can be used for deriving nonparametric Limits of Agreement. For sample sizes exceeding 80 observations, more advanced quantile estimators, such as the Harrell-Davis and estimators of Sfakianakis-Verginis type, which use all the observed differences, performed likewise well, but may be considered intuitively more appealing than simple sample quantile estimators that are based on only two observations per quantile.
  • 3.9K
  • 27 Oct 2020
Topic Review
Euro Health Consumer Index
Euro Health Consumer Index (EHCI) is a comparison of European health care systems based on waiting times, results, and generosity. The information is presented as a graphic index. EHCI was produced 2005–2009 and 2012–2016 by Health Consumer Powerhouse. The 2014 ranking included 37 countries measured by 48 indicators. It claims to measure the "consumer friendliness" of healthcare systems. It does not claim to measure which European state has the best healthcare system, but it does produce specialist Indexes on Diabetes, Cardiac Care, HIV, Headache and Hepatitis. In 2006 France was the champion with 768 points out of 1000. In the 2015 results the same performance would have given the 13th position among 35 countries because of the widespread improvements in standards. While no bias in favour of any health system was alleged, the index was criticised in the British Medical Journal by Martin McKee and others from the European Observatory on Health Systems and Policies in February 2016. Points they made included: A survey by the Centre for Population Change in 2019 produced results consistent with the index.
  • 3.8K
  • 09 Nov 2022
Topic Review
Naturopathy
Naturopathy, or naturopathic medicine, is a form of alternative medicine. It employs an array of pseudoscientific practices branded as "natural", "non-invasive", or promoting "self-healing". The practices of naturopaths, the practitioners of naturopathic medicine, vary widely and are difficult to generalize. Treatments range from outright quackery, like homeopathy, to widely accepted practices like psychotherapy. The ideology and methods of naturopathy are based on vitalism and folk medicine rather than evidence-based medicine (EBM), although some practitioners may use techniques supported by EBM. Naturopathic practitioners commonly recommend against following modern medical practices, including but not limited to medical testing, drugs, vaccinations, and surgery. Instead, naturopathic practice relies on unscientific notions, often leading naturopaths to diagnoses and treatments that have no factual merit. Naturopathy is considered by the medical profession to be ineffective and harmful, raising ethical issues about its practice. In addition to condemnations and criticism from the medical community, such as the American Cancer Society, naturopaths have repeatedly been denounced as and accused of being charlatans and practicing quackery. Naturopaths are known for their frequent campaigning for legal recognition in the United States . It is illegal in two U.S. states and tightly regulated in many others. Some states have lax regulations, however, and may allow naturopaths to perform minor surgery or even prescribe drugs. While some schools exist for naturopaths, and some jurisdictions allow such practitioners to call themselves doctors, the lack of accreditation and scientific medical training means they lack the competency of true medical doctors.
  • 3.8K
  • 24 Oct 2022
Topic Review
Health-Promoting Beverages
Tea, a beverage made from the processed leaves of the tea plant, Camellia sinensis, and herbal infusions, were primarily consumed to their pleasant taste. Nowadays, are also consumed due to the existence of nutraceutical compounds in the herbs used, such as polyphenols.
  • 3.8K
  • 30 Oct 2020
Topic Review
Stress
Stress, either physiological, biological or psychological, is an organism's response to a stressor such as an environmental condition. Stress is the body's method of reacting to a condition such as a threat, challenge or physical and psychological barrier. There are two hormones that an individual produces during a stressful situation, these are well known as adrenaline and cortisol. Stimuli that alter an organism's environment are responded to by multiple systems in the body. In humans and most mammals, the autonomic nervous system and hypothalamic-pituitary-adrenal (HPA) axis are the two major systems that respond to stress. The sympathoadrenal medullary (SAM) axis may activate the fight-or-flight response through the sympathetic nervous system, which dedicates energy to more relevant bodily systems to acute adaptation to stress, while the parasympathetic nervous system returadrenaliney to homeostasis. The second major physiological stress-response center, the HPA axis, regulates the release of cortisol, which influences many bodily functions such as metabolic, psychological and immunological functions. The SAM and HPA axes are regulated by several brain regions, including the limbic system, prefrontal cortex, amygdala, hypothalamus, and stria terminalis. Through these mechanisms, stress can alter memory functions, reward, immune function, metabolism and susceptibility to diseases. Disease risk is particularly pertinent to mental illnesses, whereby chronic or severe stress remains a common risk factor for several mental illnesses. One system suggests there are five types of stress labeled "acute time-limited stressors", "brief naturalistic stressors", "stressful event sequences", "chronic stressors", and "distant stressors". An acute time-limited stressor involves a short-term challenge, while a brief natural stressor involves an event that is normal but nevertheless challenging. A stressful event sequence is a stressor that occurs, and then continues to yield stress into the immediate future. A chronic stressor involves exposure to a long-term stressor, and a distant stressor is a stressor that is not immediate.
  • 3.8K
  • 28 Oct 2022
Topic Review
Left-Brain Interpreter
The left-brain interpreter is a neuropsychological concept developed by the psychologist Michael S. Gazzaniga and the neuroscientist Joseph E. LeDoux. It refers to the construction of explanations by the left brain hemisphere in order to make sense of the world by reconciling new information with what was known before. The left-brain interpreter attempts to rationalize, reason and generalize new information it receives in order to relate the past to the present. Left-brain interpretation is a case of the lateralization of brain function that applies to "explanation generation" rather than other lateralized activities. Although the concept of the left-brain interpreter was initially based on experiments on patients with split-brains, it has since been shown to apply to the everyday behavior of people at large.
  • 3.7K
  • 21 Oct 2022
Topic Review
Tuskegee Syphilis Experiment
The Tuskegee Study of Untreated Syphilis in the African American Male was a clinical study conducted between 1932 and 1972 by the United States Public Health Service. The purpose of this study was to observe the natural history of untreated syphilis; the African-American men in the study were only told they were receiving free health care from the Federal government of the United States. The Public Health Service started the study in 1932 in collaboration with Tuskegee University (then the Tuskegee Institute), a historically black college in Alabama. Investigators enrolled in the study a total of 600 impoverished, African-American sharecroppers from Macon County, Alabama. Of these men, 399 had latent syphilis, with a control group of 201 men who were not infected. As an incentive for participation in the study, the men were promised free medical care, but were deceived by the PHS, who disguised placebos, ineffective methods, and diagnostic procedures as treatment. The men who had syphilis were never informed of their diagnosis, despite the risk of infecting others, and the fact that the disease could lead to blindness, deafness, mental illness, heart disease, bone deterioration, collapse of the central nervous system, and death.. According to the Centers for Disease Control and Prevention, the men were told that they were being treated for "bad blood,” a colloquialism that described various conditions such as syphilis, anemia and fatigue. "Bad blood"—specifically the collection of illnesses the term included—was a leading cause of death within the southern African-American community. The men were initially told that the study was only going to last six months, but it was extended to 40 years. After funding for treatment was lost, the study was continued without informing the men that they would never be treated. None of the infected men were treated with penicillin despite the fact that by 1947, the antibiotic had become the standard treatment for syphilis. Study clinicians could have chosen to treat all syphilitic subjects and close the study, or split off a control group for testing with penicillin. Instead, they continued the study without treating any participants; they withheld treatment and information about it from the subjects. In addition, scientists prevented participants from accessing syphilis treatment programs available to other residents in the area. The study continued, under numerous Public Health Service supervisors, until 1972, when a leak to the press resulted in its termination on November 16 of that year. The victims of the study, all African-American, included numerous men who died of syphilis, 40 wives who contracted the disease and 19 children born with congenital syphilis. The 40-year Tuskegee Study of Untreated Syphilis in the African American Male study was a major violation of ethical standards. Researchers knowingly failed to treat participants appropriately after penicillin was proven to be an effective treatment for syphilis and became widely available. Moreover, participants remained ignorant of the study clinicians’ true purpose, which was to observe the natural course of untreated syphilis. The revelation in 1972 of study failures by a whistleblower, Peter Buxtun, led to major changes in U.S. law and regulation concerning the protection of participants in clinical studies. Now studies require informed consent, communication of diagnosis and accurate reporting of test results. The Tuskegee Syphilis Study, cited as "arguably the most infamous biomedical research study in U.S. history," led to the 1979 Belmont Report and to the establishment of the Office for Human Research Protections (OHRP). It also led to federal laws and regulations requiring institutional review boards for the protection of human subjects in studies involving them. The OHRP manages this responsibility within the United States Department of Health and Human Services (HHS). On May 16, 1997, President Bill Clinton formally apologized on behalf of the United States to victims of the study.
  • 3.7K
  • 07 Nov 2022
Topic Review
Mindfulness
Mindfulness is the psychological process of purposely bringing one's attention to experiences occurring in the present moment without judgment which one develops through the practice of meditation and through other training. Mindfulness derives from sati, a significant element of Buddhist traditions, and based on Zen, Vipassanā, and Tibetan meditation techniques. Though definitions and techniques of mindfulness are wide-ranging, Buddhist traditions explain what constitutes mindfulness such as how past, present and future moments arise and cease as momentary sense impressions and mental phenomena. Individuals who have contributed to the popularity of mindfulness in the modern Western context include Thích Nhất Hạnh (1926– ), Herbert Benson (1935– ), Jon Kabat-Zinn (1944– ), and Richard J. Davidson (1951– ). Clinical psychology and psychiatry since the 1970s have developed a number of therapeutic applications based on mindfulness for helping people experiencing a variety of psychological conditions. Mindfulness practice has been employed to reduce depression, to reduce stress, anxiety, and in the treatment of drug addiction. Programs based on mindfulness models have been adopted within schools, prisons, hospitals, veterans' centers, and other environments, and mindfulness programs have been applied for additional outcomes such as for healthy aging, weight management, athletic performance, helping children with special needs, and as an intervention during the perinatal period. Clinical studies have documented both physical- and mental-health benefits of mindfulness in different patient categories as well as in healthy adults and children. Research studies have shown a positive relationship between trait mindfulness (see below) and psychological health. The practice of mindfulness appears to provide therapeutic benefits to people with psychiatric disorders, including moderate benefits to those with psychosis. Studies also indicate that rumination and worry contribute to a variety of mental disorders, and that mindfulness-based interventions can reduce both rumination and worry. Further, the practice of mindfulness may be a preventive strategy to halt the development of mental-health problems. There is also evidence that suggest engaging in mindfulness meditation may influence physical health. For example, the psychological habit of repeatedly dwelling on stressful thoughts (i.e., rumination) appears to intensify the physiological effects of the stressor (as a result of the continual activation of the sympathetic nervous system and the hypothalamus-pituitary-adrenal axis) with the potential to lead to physical health related clinical manifestations. Studies indicate that mindfulness meditation, which brings about reductions in rumination, may alter these biological clinical pathways. Further, research indicates that mindfulness may favourably influence the immune system as well as inflammation,Cite error: Closing missing for tag
  • 3.6K
  • 12 Oct 2022
Topic Review
Immigrant Paradox
The immigrant paradox is that recent immigrants often outperform more established immigrants and non-immigrants on a number of health-, education-, and conduct- or crime-related outcomes, despite the numerous barriers they face to successful social integration. According to the UN, the number of first-generation immigrants worldwide is 244 million. These large-scale population changes worldwide have led many scholars, across fields, to study the acculturation and adjustment of immigrants to their new homes. Specifically, researchers have examined immigrant experiences as they pertain to educational attainment, mental and physical health, and conduct/crime. Researchers have tried to understand why later generations seem to perform less well than their forebears. They have found that it can be explained by non-optimal methodology and differences in the way generations are modified by the host culture.
  • 3.6K
  • 29 Nov 2022
Topic Review
Thalidomide Scandal
In the late 1950s and early 1960s, the use of thalidomide in pregnant women in 46 countries resulted in the "biggest man‐made medical disaster ever," with over 10,000 children born with a range of severe deformities, such as phocomelia, and thousands of miscarriages. Thalidomide was introduced in 1956 and was aggressively marketed by the German pharmaceutical company Chemie Grünenthal as a medication for anxiety, trouble sleeping, "tension", and morning sickness. It was introduced as a sedative and medication for morning sickness without having been tested on pregnant women. While initially deemed to be safe in pregnancy, concerns regarding birth defects were noted in 1961, and the medication was removed from the market in Europe that year.
  • 3.6K
  • 09 Nov 2022
Topic Review
Blood Typing
Blood typing is a medical laboratory test used to identify the antigens on a person's red blood cells, which determine their blood type. Routine blood typing involves determining the ABO and RhD (Rh factor) type, and is performed before blood transfusions to ensure that the donor blood is compatible. It is also used to help diagnose hemolytic disease of the newborn, a condition caused by incompatibility between the blood types of a mother and her baby. ABO typing involves both identification of ABO antigens on red blood cells (forward grouping) and identification of ABO antibodies in the plasma (reverse grouping). Other blood group antigens, such as RhC/c and E/e or Kell, may be tested for in special situations. Blood typing is usually performed using serologic methods, which use reagents containing antibodies, called antisera, to identify blood group antigens. Serologic methods rely on the ability of antibodies to cause red blood cells to clump together when they bind to antigens on the cell surface, a phenomenon called agglutination. A number of serologic methods are available, ranging from manual blood typing using test tubes or slides to fully automated systems. Blood types can also be determined through genetic testing, which is used when conditions that interfere with serologic testing are present or when a high degree of accuracy in antigen identification is required. A number of conditions can cause false or inconclusive results in blood typing. When these issues affect ABO typing, they are called ABO discrepancies. ABO discrepancies must be investigated and resolved before the person's blood type is reported. There are different procedures for resolving ABO discrepancies depending on the underlying causes. Other sources of error in blood typing include the "weak D" phenomenon, in which people who are positive for the RhD antigen show weak or negative reactions when tested for RhD, and the presence of Immunoglobulin G antibodies on red blood cells, which interferes with typing for some blood group antigens.
  • 3.6K
  • 25 Oct 2022
Topic Review
Self-Amplifying mRNA Vaccine
The core principle behind mRNA vaccines is to encode the antigen in the mRNA and then to deliver the transcript to the host cell cytoplasm using a non-viral delivery system, allowing antigen expression and induction of an antigen-specific immune response. Self-amplifying RNA (saRNA) is a type of mRNA that also encodes viral replicase, which enables the RNA to self-replicate upon delivery into the cell.
  • 3.6K
  • 13 Feb 2021
Topic Review
Point-Of-Care or Point-Of-Need Diagnostic Tests
In the recent years, the progress of international trade and travel has led to an increased risk of emerging infections. Around 75 percent of the pathogens causing these infections are of animal origin. Point-of-care tests (POCT) and point-of-need tests (PONT) have been established in order to directly provide accurate and rapid diagnostics at field level, the patient bed-side or at the site of outbreaks. These assays can help physicians and decision makers to take the right action without delay. Typically, POCT and PONT rely on genomic identification of pathogens or track their immunological fingerprint. Recently, protocols for metagenomic diagnostics in the field have been developed.
  • 3.5K
  • 20 Apr 2021
Topic Review
Multi-Drug Resistance
Multidrug-resistance is a long debated term. Since 1980 it was used to imply the resistance of a microorganism to multiple pharmaceutical agents, without the number or types of antimicrobials being specified.Currently, the most widely accepted definition of multidrug-resistant (MDR) bacteria include a lack of susceptibility in three or more antimicrobial categories active against the isolated microorganism.
  • 3.4K
  • 27 Aug 2020
Topic Review
Implant–Abutment Connections
Different implant–abutment connections have been developed to reduce mechanical and biological failure. The most frequent complications are loss of preload, screw loosening, abutment or implant fracture, deformations at the different interfaces, and bacterial microleakage.  To review the evidence indicating whether the implant–abutment connection type is significant regarding the following issues: (1) maintenance of the preload in static and dynamic in vitro studies; (2) assessment of possible deformations at the implant–abutment interfaces, after repeated application of the tightening torque; (3) evaluation of the sealing capability of different implant connections against microleakage. 
  • 3.3K
  • 08 Dec 2020
Topic Review
Acrylic Bone Cements
Acrylic bone cements (ABC) are widely used in orthopedics for joint fixation, antibiotic release, and bone defect filling, among others. Most of the commercial ABCs available today consist of two components, one solid, based mainly on poly(methyl methacrylate) (PMMA), and one liquid, based on methyl methacrylate (MMA), which are mixed and, through the polymerization reaction of the monomer, transformed into a hardened cement paste. 
  • 3.2K
  • 22 Dec 2020
Topic Review
Virtual Reality for Rehabilitation
Virtual reality (VR) is a trending, widely accessible, contemporary technology of increasing utility to biomedical and health applications. VR is the technological experience that allows for a full immersion in virtual spaces with which you can interact via specific wearable or using only your hand. A key feature of all VR applications is interaction. VR ranges from non-immersive to fully immersive, depending on the degree to which the user is isolated from the physical surroundings when interacting with the virtual environment. Non-immersive virtual reality allows for interacting with the environment through mouse or joystick; immersive virtual reality, instead, uses tools that are connected to the human body in order to perform the same motor task. Despite the growing evidence of the positive effects of VR in rehabilitation of functional and cognitive abilities, some systems still raised concerns regarding their acceptability with complex clinical populations, as, for example, the older people. In particular, during trials with immersive systems, few adverse events have been described by participants, including headache and dizziness. Finally, little is known about the perceived effect of the exposure at multisensory input during a complex activity, such as treadmill walking with VR in patients during post-stroke rehabilitation to improve balance and gait ability.
  • 3.2K
  • 30 Jul 2020
Topic Review
Biological Half-life
The biological half-life of a biological substance is the time it takes for half to be removed by biological processes. This concept is used when the rate of removal is roughly exponential. It is often denoted by the abbreviation [math]\displaystyle{ t_{\frac{1}{2}} }[/math]. This is used to measure the removal of things such as metabolites, drugs, and signalling molecules from the body. Typically, the biological half-life refers to the body's natural cleansing through the function of the liver and through the excretion of the measured substance through the kidneys and intestines. In a medical context, half-life explicitly describes the time it takes for the blood plasma concentration of a substance to halve (plasma half-life) its steady-state when circulating in the full blood of an organism. This measurement is useful in medicine and pharmacology because it helps determine how much of a drug needs to be taken and how frequently it needs to be taken if a certain average amount is needed constantly. In contrast, the stability of a substance direct in plasma is described with plasma stability that is essential to ensure accurate analysis of drugs in plasma and for Drug discovery. The relationship between the biological and plasma half-lives of a substance can be complex depending on the substance in question, due to factors including accumulation in tissues (protein binding), active metabolites, and receptor interactions.
  • 3.1K
  • 17 Nov 2022
Topic Review
Ibrexafungerp
Ibrexafungerp is a first-in-class IV/oral triterpenoid antifungal agent. Similar in mechanism of action to echinocandins, ibrexafungerp inhibits (1→3)-β-D-glucan synthase, a key component of the fungal cell wall, resulting in fungicidal activity against Candida spp. Ibrexafungerp demonstrates broad in vitro activity against Candida spp.,Aspergillus spp., dimorphic fungi Pneumocystis and other emerging yeasts and mold pathogens including azole and echinocandin-resistant isolates. It is currently in late clinical development for treatment and prevention of vulvovaginal candidiasis. Other ongoing trials include treatment of serious fungal infections, including, invasive candidiasis, Candida auris infections, invasive aspergillosis and refractory fungal disease in patients not responding to or who are intolerant to standard of care .
  • 3.1K
  • 17 Mar 2021
Topic Review
Reduced Affect Display
Reduced affect display, sometimes referred to as emotional blunting, is a condition of reduced emotional reactivity in an individual. It manifests as a failure to express feelings (affect display) either verbally or nonverbally, especially when talking about issues that would normally be expected to engage the emotions. Expressive gestures are rare and there is little animation in facial expression or vocal inflection. Reduced affect can be symptomatic of autism, schizophrenia, depression, posttraumatic stress disorder, depersonalization disorder, schizoid personality disorder or brain damage. It may also be a side effect of certain medications (e.g., antipsychotics and antidepressants). Reduced affect should be distinguished from apathy and anhedonia, which explicitly refer to a lack of emotion, whereas reduced affect is a lack of emotional expression (affect display) regardless of whether emotion (underlying affect) is actually reduced or not.
  • 3.1K
  • 17 Nov 2022
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