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Bordetella pertussis bacteria
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Bordetella pertussis
"Whooping Cough"
Encounter and Colonization
Bordetella pertussis is a highly communicable agent and is transmitted person-to-person via airborne droplets or direct contact with discharges from the respiratory mucous membranes of an infected person. This small, gram-negative coccobacillus is non-motile, aerobic and fastidious. B. pertussis colonizes the respiratory tract including the mouth, nose, throat and beginning of the lungs of young children worldwide. The bacteria bind to ciliated cells in the respiratory mucosa by producing adhesions. Filamentous hemagglutinin on the cell surface and pertussis toxin (Ptx) both help the bacteria in binding. Filamentous hemagglutinin binds to the galactose residues on the glycolipid of the ciliated cells. Ptx, in its cell-bound form, binds to the glycolipid lactosylceramide, which is also found on the ciliated cells. Ptx binds to the surface of phagocytes as well, causing phagocytosis of the bacteria. This mechanism may lead to enhanced survival as an intracellular parasite. Adding to its many purposes, Ptx deregulates the host cell adenylate cyclase activity. The A subunit of this AB toxin, affects the G protein responsible for inhibiting adenylate cyclase. This leads to an increase in cyclic adenosine monophosphate (cAMP) creating detrimental metabolic changes in the host cells.
Additional Toxins
Also contributing to the virulence of the bacteria are the exotoxins including invasive adenylate cyclase, tracheal cytotoxin, and lethal toxin. Invasive adenylate cyclase reduces local phagocytic activity as well as acting as a hemolysin. Tracheal toxin affects the ciliated respiratory epithelium by inhibiting the ciliary beating. This kills the cells and causes them to be eliminated from the mucosa. Tracheal toxin also stimulates the release of IL-1, which causes fever. Lastly, lethal toxin causes inflammation and local necrosis at infection sites.
Because B. pertussis is a gram-negative bacteria, it possesses the endotoxin lipopolysaccharide (LPS). However, its LPS is different from that of the other gram-negative bacteria, in that it is heterogeneous with an alternative form of the Lipid A, called Lipid X. Although not fully understood at the time, it seems that Lipid X has a greater capacity for virulence.
Pathogenesis
After an incubation period of five to ten days, or as long as 21 days, numerous symptoms can be observed. The symptoms come in two stages. The first stage consists of common cold symptoms such as sneezing, runny nose, low-grade fever, and a mild cough. It is during this time that the disease is most contagious, and it lasts from one to two weeks.
[1, 4, 5, 9, 13] There have been no documented cases where a human has contracted the disease from another human. [4] It appears, based on field and lab data, that infection requires direct contact with the virus through means such as contact with infective bodily secretions, urine, or tissues. [12] It is unknown to scientists how the virus can be maintained in the bat populations and avoids extinction as the host species becomes immune to its presence. [14] The incubation period from time of infection to the onset of symptoms is about 5-14 days in experimentally induced animals [4] and 8-14 days in natural field cases.
Symptoms, which include diarrhea and abdominal pain, usually begin two to eight days after a person has been exposed to the bacteria and resolve within a week.
For the disease to occur, Bordetella pertussis evades the host immune system and is disseminate in the lower respiratory tract. Inhaled bacteria droplets then attach to the ciliated epithelial cells in the nasal-pharynx and trachea. It is at this point that Bordetella pertussis produces virulent factors that are classified into two; adhesins and toxins. Adhesins mediate bacterial attachment to the epithelial cells while toxins that mediate the host immune system. Adhesins include; filamentous haemagglutinin, fimbriae and pertactin while toxins include pertussis toxin, tracheal cytotoxin and adenylate cyclase toxin(1). To understand the role of these virulence factors in whooping cough disease, a mouse model has been used (2).
In this article Dr. Gates reveals how despite the success of television shows such as “The Cosby Show” stereotyping of blacks on T.V. is still prevalent.
Cystic Fibrosis is an inherited disease characterized by the buildup of thick, sticky mucous that can cause severe damage to the body’s organs. Mucous is usually a slippery substance that lubricates and protects the linings of the airway, digestive system, reproductive system and other organs and tissue. Problems with digestion can lead to diarrhea, malnutrition, poor growth, and weight-loss. Due to the abnormally thick mucous it can can clog airways, leading to breathing problems and bacterial infections in the lungs. Bacterial infections can lead to coughing, wheezing and inflammation. Overtime these infections can lead to permanent damage in the lungs including the formation of scar tissue, known as fibrosis and cysts in the lungs (Genetics Home Reference, 2013). The symptoms and signs of this disease vary but mostly include progressive damage to the respiratory system and chronic digestive system problems. An individuals’ lungs who are infected by cystic fibrosis have bacteria from an early stage. This bacteria can spread to the small airways, leading to the formation of bacterial micro-environments known as biofilms. Biofilms are difficult for antibodies to penetrate, therefore the bacteria repeatedly damage the lung and gradually remodel the airways, resulting in difficultly to eradicate the infection (Welsh, 1995). Cystic fibrosis patients may even have their airways chronically colonized be filamentous fungi and/or yeasts. Most men with cystic fibrosis have congenital bilateral absence of the vas deferens (CBAVD), a condition in which the tubes that carry sperm are blocked by mucous and do not develop properly. As well, women may experience complications in pregnancy. Either the c...
The brain controls pretty much everything you do, even while asleep. When drugs enter the brain, the substance can disturb the organ and change how the brain performs its duties to function. These changes are what lead to a continuous yearning for drugs or addiction. The signals a drug sends to the brain get confused with that of a euphoric chemical called dopamine, which makes you feel good. After repeated use of drugs the brain in most cases becomes damaged and irreparable. Adolescents are more prone to addiction due to the fact that their brains are not yet fully developed. The lack of maturity of the brain give health specialist the theory that drug use at an older age will reduce the chances of addiction.
The most commonly abused substances are Nicotine, Inhalants, Alcohol, Cocaine, Amphetamines, Prescription medications, Heroin, Ecstasy and Marijuana. 1a(National Institute on Drug Abuse, 2011) Initially, a person may find themselves using substances voluntarily and with confidence that they will be able to dictate their personal use. However, over the period of time that drug use is repeated, changes are taking place throughout the brain, whether it is functionally or structurally. Drugs contain chemicals that enter the communication system of the brain and disturb the way in which nerve cells would typically send, receive, and process information. The chemicals within these drugs will cause a disruption to the communication system by either imitating the brain’s natural chemical messengers or by over-stimulating the brains “reward system” by sending mass amounts of dopamine. As an individual prolongs his or her use of these substances, they may develop an addiction.
There are many biological factors that are involved with the addicted brain. "The addicted brain is distinctly different from the nonaddicted brain, as manifested by changes in brain metabolic activity, receptor availability, gene expression, and responsiveness to environmental cues." (2) In the brain, there are many changes that take place when drugs enter a person's blood stream. The pathway in the brain that the drugs take is first to the ventral tegmentum to the nucleus accumbens, and the drugs also go to the limbic system and the orbitofrontal cortex, which is called the mesolimbic reward system. The activation of this reward system seems to be the common element in what hooks drug users on drugs (2).
Kids are very impressionable human beings, they see one thing and they begin to imitate this thing. Reality TV enables kids to think for themselves. Going back to the show Maury, it is mostly African American teenagers seen yelling and screaming at the top of their lungs making a spectacle of themselves. Teenagers watch reality television more than anything else. One statistic states, “On average, a teen will watch 28 hours of television per week, adding up to almost 15,000 hours a year” (reportherald.com). Shows such as Love & Hip Hop, exposes teens to
There have been many twists and turns in the ways in which the black experience was represented in mainstream America cinema. But the repetition of stereotypical figures, drawn from ‘slavery days’ has never entirely disappeared (Hall, 1997). A Stereotype can be described as a widely held but fixed and oversimplified image or idea of a particular type of person or thing (Oxford University Press, 2014) and can affect the target by getting hold of a few simple, vivid, memorable, easily grouped and widely recognised characteristic, about a person and reduce everything to the specific traits and exaggerate them (Hall, 1997). One of the most well-known stereotype has to be the ‘Black-stereotype’ which can be seen in all media productions ranging from news, film, music videos, reality television and other programming and forms of entertainment. Beginning around 1830, the history of African-Americans is a centuries old struggle against oppression and discrimination and because of these major issues, popular representations of racial ‘difference’ during slavery, has caused two main themes that are seen as blackface stereotypes today.
This is depicted by mental and physical exhaustion, increased periods of sleep and depression. Users will generally crave the drug and want to use it again. https://www.dea.gov/druginfo/drug_data_sheets/Cocaine.pdf Users become tolerant of the drug rather quickly which causes them to take higher doses to experience that euphoric high.
Yes, certain drugs interfere with the brain’s natural communication system and its validity process. Provided the brain is composed of neurons (nerve cells) from one to another neuron. Which prevents the receptor from communicating properly as it conveyance between the neurons. Drugs such as marijuana and heroin satirist the chemical structure of neurotransmitters, manipulating receptors into generating and transmitting messages. Even though they’re compared to natural neurotransmitters, these drugs affect neurons differently and transmit abnormal messages. Other drugs cause neurons to release enormous amounts of neurotransmitters than normal, or prevent the transporters from recovering neurotransmitters. This is the way drugs like amphetamine
Most of these televisions show; show only the negative events that occur in certain African American individuals. According to the Atlanta, Black Star website article written by Ricky Riley states, “This VH1 reality show is probably the most intense reality to date because it shows an array of verbal and physical abuse in Black relationships that is disturbing”. The media boosts up these kinds of shows because it catches the viewer's eyes. These types of shows cause the viewers to have a certain look on African American males and females because of what is showed off of the television. If the media would stop showing these kinds of shows, then people would not have a certain outlook on African
Measles Measles is a highly contagious disease. It is caused by an RNA virus that changes constantly. Measles symptoms usually include a bad cough, sneezing, runny nose, red eyes, sensitivity to light, and a very high fever. Red patches with white grain like centers appear along the gum line in the mouth two to four days after the first symptoms show. These patches are called Koplik spots because Henry Koplick first noticed them in 1896.
In the 15th century, tea became such a revered beverage that a whole culture developed around it, culminating in the tea ceremony. The drinking of tea became highly structured recreation centered on such aesthetic and philosophical concepts as wabi (austere beauty) and sabi (tranquility). Eventually the tea ceremony became synonymous with cultural refinement, and court nobles and the wealthy would frequently participate in the ritual. It was only much later that the custom of tea drinking spread to the average person and tea became an indispensable daily beverage. The entrenched in everyday life, it has become an indispensable to drink tea in the life and culture of the Japanese. In addition, the deep