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Topic Review
Pathogenic Bacteria
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract. The body is continually exposed to many species of bacteria, including beneficial commensals, which grow on the skin and mucous membranes, and saprophytes, which grow mainly in the soil and in decaying matter. The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms. Pathogenic bacteria are specially adapted and endowed with mechanisms for overcoming the normal body defences, and can invade parts of the body, such as the blood, where bacteria are not normally found. Some pathogens invade only the surface epithelium, skin or mucous membrane, but many travel more deeply, spreading through the tissues and disseminating by the lymphatic and blood streams. In some rare cases a pathogenic microbe can infect an entirely healthy person, but infection usually occurs only if the body's defence mechanisms are damaged by some local trauma or an underlying debilitating disease, such as wounding, intoxication, chilling, fatigue, and malnutrition. In many cases, it is important to differentiate infection and colonization, which is when the bacteria are causing little or no harm. Caused by Mycobacterium tuberculosis bacteria, one of the diseases with the highest disease burden is tuberculosis, which killed 1.4 million people in 2019, mostly in sub-Saharan Africa. Pathogenic bacteria contribute to other globally important diseases, such as pneumonia, which can be caused by bacteria such as Streptococcus, Pneumococcus and Pseudomonas, and foodborne illnesses, which can be caused by bacteria such as Shigella, Campylobacter, and Salmonella. Pathogenic bacteria also cause infections such as tetanus, typhoid fever, diphtheria, syphilis, and leprosy. Pathogenic bacteria are also the cause of high infant mortality rates in developing countries. Most pathogenic bacteria can be grown in cultures and identified by Gram stain and other methods. Bacteria grown in this way are often tested to find which antibiotics will be an effective treatment for the infection. For hitherto unknown pathogens, Koch's postulates are the standard to establish a causative relationship between a microbe and a disease.
  • 4.6K
  • 07 Nov 2022
Topic Review
Lipid-Based Nanoparticles
COVID-19 vaccines have been developed with unprecedented speed which would not have been possible without decades of fundamental research on delivery nanotechnology. Lipid-based nanoparticles have played a pivotal role in the successes of COVID-19 vaccines and many other nanomedicines, such as Doxil® and Onpattro®, and have therefore been considered as the frontrunner in nanoscale drug delivery systems. In this review, we aim to highlight the progress in the development of these lipid nanoparticles for various applications, ranging from cancer nanomedicines to COVID-19 vaccines. The lipid-based nanoparticles discussed in this review are liposomes, niosomes, transfersomes, solid lipid nanoparticles, and nanostructured lipid carriers. We particularly focus on the innovations that have obtained regulatory approval or that are in clinical trials. We also discuss the physicochemical properties required for specific applications, highlight the differences in requirements for the delivery of different cargos, and introduce current challenges that need further development. This review serves as a useful guideline for designing new lipid nanoparticles for both preventative and therapeutic vaccines including immunotherapies.
  • 4.6K
  • 19 May 2021
Topic Review
List of Phobias
The English suffixes -phobia, -phobic, -phobe (from Greek φόβος phobos, "fear") occur in technical usage in psychiatry to construct words that describe irrational, abnormal, unwarranted, persistent, or disabling fear as a mental disorder (e.g. agoraphobia), in chemistry to describe chemical aversions (e.g. hydrophobic), in biology to describe organisms that dislike certain conditions (e.g. acidophobia), and in medicine to describe hypersensitivity to a stimulus, usually sensory (e.g. photophobia). In common usage, they also form words that describe dislike or hatred of a particular thing or subject (e.g. homophobia). The suffix is antonymic to -phil-. For more information on the psychiatric side, including how psychiatry groups phobias such as agoraphobia, social phobia, or simple phobia, see phobia. The following lists include words ending in -phobia, and include fears that have acquired names. In some cases, the naming of phobias has become a word game, of notable example being a 1998 humorous article published by BBC News. In some cases, a word ending in -phobia may have an antonym with the suffix -phil-, e.g. Germanophobe/Germanophile. Many -phobia lists circulate on the Internet, with words collected from indiscriminate sources, often copying each other. Also, a number of psychiatric websites exist that at the first glance cover a huge number of phobias, but in fact use a standard text to fit any phobia and reuse it for all unusual phobias by merely changing the name. Sometimes it leads to bizarre results, such as suggestions to cure "prostitute phobia". Such practice is known as content spamming and is used to attract search engines. An article published in 1897 in American Journal of Psychology noted "the absurd tendency to give Greek names to objects feared (which, as Arndt says, would give us such terms as klopsophobia – fear of thieves, triakaidekaphobia – fear of the number 13....)".
  • 4.6K
  • 07 Nov 2022
Topic Review
Natural Reservoir
In infectious disease ecology and epidemiology, a natural reservoir, also known as a disease reservoir or a reservoir of infection, is the population of organisms or the specific environment in which an infectious pathogen naturally lives and reproduces, or upon which the pathogen primarily depends for its survival. A reservoir is usually a living host of a certain species, such as an animal or a plant, inside of which a pathogen survives, often (though not always) without causing disease for the reservoir itself. By some definitions a reservoir may also be an environment external to an organism, such as a volume of contaminated air or water. Because of the enormous variety of infectious microorganisms capable of causing disease, precise definitions for what constitutes a natural reservoir are numerous, various, and often conflicting. The reservoir concept applies only for pathogens capable of infecting more than one host population and only with respect to a defined target population – the population of organisms in which the pathogen causes disease. The reservoir is any population of organisms (or any environment) which harbors the pathogen and transmits it to the target population. Reservoirs may comprise one or more different species, may be the same or a different species as the target, and, in the broadest sense, may include vector species, which are otherwise distinct from natural reservoirs and should not be confused with them. Significantly, species considered reservoirs for a given pathogen may not experience symptoms of disease when infected by the pathogen. Identifying the natural reservoirs of infectious pathogens has proven useful in treating and preventing large outbreaks of disease in humans and domestic animals, especially those diseases for which no vaccine exists. In principle, zoonotic diseases can be controlled by isolating or destroying the pathogen's reservoirs of infection. The mass culling of animals confirmed or suspected as reservoirs for human pathogens, such as birds that harbor avian influenza, has been effective at containing possible epidemics in many parts of the world; for other pathogens, such as the ebolaviruses, the identity of the presumed natural reservoir remains obscure.
  • 4.2K
  • 26 Oct 2022
Topic Review
Ideas of Reference and Delusions of Reference
Ideas of reference and delusions of reference describe the phenomenon of an individual experiencing innocuous events or mere coincidences and believing they have strong personal significance. It is "the notion that everything one perceives in the world relates to one's own destiny", usually in a negative and hostile manner. In psychiatry, delusions of reference form part of the diagnostic criteria for psychotic illnesses such as schizophrenia, delusional disorder, bipolar disorder (during the elevated stages of mania), as well as schizotypal personality disorder. To a lesser extent, it can be a hallmark of paranoid personality disorder, as well as body dysmorphic disorder. Such symptoms can also be caused by intoxication, such as stimulants like methamphetamine.
  • 4.1K
  • 20 Oct 2022
Topic Review
Cholera Outbreaks and Pandemics
Seven cholera pandemics have occurred in the past 200 years, with the first pandemic originating in India in 1817. Additionally, there have been many documented cholera outbreaks, such as a 1991–1994 outbreak in South America and, more recently, the 2016–2021 Yemen cholera outbreak. Although much is known about the mechanisms behind the spread of cholera, this has not led to a full understanding of what makes cholera outbreaks happen in some places and not others. Lack of treatment of human feces and lack of treatment of drinking water greatly facilitate its spread. Bodies of water have been found to serve as a reservoir, and seafood shipped long distances can spread the disease. Between 1816 and 1923, the first six cholera pandemics occurred consecutively and continuously over time. Increased commerce, migration, and pilgrimage are credited for its transmission. Late in this period (particularly 1879–1883), major scientific breakthroughs toward the treatment of cholera develop: the first immunization by Pasteur, the development of the first cholera vaccine, and identification of the bacterium Vibrio cholerae by Filippo Pacini and Robert Koch. After a long hiatus, a seventh cholera pandemic spread in 1961. The pandemic subsided in the 1970s, but continued on a smaller scale. Outbreaks occur across the developing world to the current day. Epidemics occurred after wars, civil unrest, or natural disasters, when water and food supplies had become contaminated with Vibrio cholerae, and also due to crowded living conditions and poor sanitation. Deaths in India between 1817 and 1860 in the first three pandemics of the nineteenth century, are estimated to have exceeded 15 million people. Another 23 million died between 1865 and 1917, during the next three pandemics. Cholera deaths in the Russian Empire during a similar time period exceeded 2 million.
  • 3.9K
  • 20 Oct 2022
Topic Review
Schizoid Personality Disorder
Schizoid personality disorder (/ˈskɪtsɔɪd, ˈskɪdzɔɪd/, often abbreviated as SPD or SzPD) is a personality disorder characterized by a lack of interest in social relationships, a tendency toward a solitary or sheltered lifestyle, secretiveness, emotional coldness, detachment and apathy. Affected individuals may be unable to form intimate attachments to others and simultaneously possess a rich and elaborate but exclusively internal fantasy world. Other associated features include stilted speech, a lack of deriving enjoyment from most activities, feeling as though one is an "observer" rather than a participant in life, an inability to tolerate emotional expectations of others, apparent indifference when praised or criticized, a degree of asexuality, and idiosyncratic moral or political beliefs. Symptoms typically start in late childhood or adolescence. The cause of SPD is uncertain, but there is some evidence of links and shared genetic risk between SPD, other cluster A personality disorders (such as schizotypal personality disorder) and schizophrenia. Thus, SPD is considered to be a "schizophrenia-like personality disorder". It is diagnosed by clinical observation, and it can be very difficult to distinguish SPD from other mental disorders (such as autism spectrum disorder, with which it may sometimes overlap). The effectiveness of psychotherapeutic and pharmacological treatments for the disorder has yet to be empirically and systematically investigated. This is largely because people with SPD rarely seek treatment for their condition. Originally, low doses of atypical antipsychotics were also used to treat some symptoms of SPD, but their use is no longer recommended. The substituted amphetamine bupropion may be used to treat associated anhedonia. However, it is not general practice to treat SPD with medications, other than for the short-term treatment of acute co-occurring disorders (e.g. depression). Talk therapies such as cognitive behavioral therapy (CBT) may not be effective, because people with SPD may have a hard time forming a good working relationship with a therapist. SPD is a poorly studied disorder, and there is little clinical data on SPD because it is rarely encountered in clinical settings. Studies have generally reported a prevalence of less than 1% It is more common in males than in females. SPD is linked to negative outcomes, including a significantly compromised quality of life, reduced overall functioning even after 15 years and one of the lowest levels of "life success" of all personality disorders (measured as "status, wealth and successful relationships"). Bullying is particularly common towards schizoid individuals. Suicide may be a running mental theme for schizoid individuals, though they are not likely to actually attempt it. Some symptoms of SPD (e.g. solitary lifestyle and emotional detachment), however, have been stated as general risk factors for serious suicidal behaviour.
  • 3.7K
  • 20 Oct 2022
Topic Review
16S rRNA Next-Generation Sequencing
The 16S rRNA gene is highly conserved in all bacteria (and also archaea). Nonetheless, it contains nine hypervariable regions (V1 - V9), where sequences of these regions can be used to identify and discriminate bacterial genus, sometimes until the species level. This makes the gene a useful tool for phylogenetic studies. With the introduction of next-generation sequencing technologies, 16S rRNA next-generation sequencing (16SNGS) has allowed profiling of bacterial communities found in organisms and the environment, and lead to the discovery of many previously unculturable members of the bacteria kingdom.
  • 3.7K
  • 18 May 2021
Topic Review
Aquaporin Inhibitors
Aquaporins (AQPs) are water channel proteins that are essential to life, being expressed in all kingdoms. In humans, there are 13 AQPs, at least one of which is found in every organ system. The structural biology of the AQP family is well-established and many functions for AQPs have been reported in health and disease. AQP expression is linked to numerous pathologies including tumor metastasis, fluid dysregulation, and traumatic injury. The targeted modulation of AQPs therefore presents an opportunity to develop novel treatments for diverse conditions. Various techniques such as video microscopy, light scattering and fluorescence quenching have been used to test putative AQP inhibitors in both AQP-expressing mammalian cells and heterologous expression systems. The inherent variability within these methods has caused discrepancy and many molecules that are inhibitory in one experimental system (such as tetraethylammonium, acetazolamide, and anti-epileptic drugs) have no activity in others. Some heavy metal ions (that would not be suitable for therapeutic use) and the compound, TGN-020, have been shown to inhibit some AQPs. Clinical trials for neuromyelitis optica treatments using anti-AQP4 IgG are in progress. However, these antibodies have no effect on water transport. More research to standardize high-throughput assays is required to identify AQP modulators for which there is an urgent and unmet clinical need.
  • 3.7K
  • 06 Sep 2021
Topic Review
Sanism
Mentalism or sanism describes discrimination and oppression against a mental trait or condition a person has, or is judged to have. This discrimination may or may not be characterized in terms of mental disorder or cognitive impairment. The discrimination is based on numerous factors such as stereotypes about neurodivergence, for example autism, learning disorders, ADHD, bipolar, schizophrenia, and personality disorders, specific behavioral phenomena such as stuttering and tics, or intellectual disability. Like other forms of discrimination such as sexism and racism, mentalism involves multiple intersecting forms of oppression, complex social inequalities and imbalances of power. It can result in covert discrimination by multiple, small insults and indignities. It is characterized by judgments of another person's perceived mental health status. These judgments are followed by actions such as blatant, overt discrimination which may include refusal of service, or the denial of human rights. Mentalism impacts how individuals are treated by the general public, by mental health professionals, and by institutions, including the legal system. The negative attitudes involved may also be internalized. The terms mentalism, from "mental", and sanism, from "sane", have become established in some contexts, though concepts such as social stigma, and in some cases ableism, may be used in similar but not identical ways. While mentalism and sanism are used interchangeably, sanism is becoming predominant in certain circles, such as academics, those who identify as mad and mad advocates and in a socio-political context where sanism is gaining ground as a movement. The movement of sanism is an act of resistance among those who identify as mad, consumer survivors, and mental health advocates. In academia evidence of this movement can be found in the number of recent publications about sanism and social work practice. Mentalism tends to be referred as mental disability, distinguishing itself from ableism, which refers to physical disability.
  • 3.6K
  • 02 Nov 2022
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