angiogenesis blood vessel growth :: essays research papers

PDFG induces proliferation of fibroblasts, microglia, and smooth muscle. It is stored in platelet granules and is released following platelet aggregation. PDGF may also serve as a chemotactic agent for inflammatory cells. Platelets circulate in the blood and are derived from megakaryocytic in the marrow. Like erythrocytes, they are anucleate. However, unlike erythrocytes, they contain numerous intracytoplasmic granules and are the source of numerous proinflammatory mediators. In fact, they are quantitatively the greatest single source of vasoactive amines in the body. They also are a rich source of thromboxane A2. It is their activation that, in part, initiates the vascular phase of the acute inflammatory response (see Fig. 2-13 in text). To have them play this role makes imminently good sense, because they are present in large numbers throughout the circulation, i.e., some are always in close proximity to an inciting stimulus. Vasoactive Literally translated, this adjective means that a substance has the capacity to alter the physiologic state, especially the tone and caliber, of a vessel. Platelet-Derived Growth Factor (PDGF), a dimeric glycoprotein composed of two A and/or B chains, is the principal mitogen in serum for mesenchymal cells. Applications include culture of various cell types derived from connective tissue. It can also be used to study chemotaxis, wound healing, and bone repair. Another member of the PDGF family is the Vascular Endothelial Growth Factor (VEGF) with endothelial cell-specific activities (e.g., angiogenic and mitogenic factor). Platelet-derived growth factor (PDGF) [1-3 reviews], a factor released from platelets upon clotting, is responsible for stimulating the proliferation of fibroblasts in vitro [4-6]. PDGF is also produced by a number of cell types besides platelets and is mitogen for vascular smooth muscle cells, bone cells, cartilage cells, connective tissue cells and some blood cells [7-9]. PDGF is stored in platelet alpha granules and released upon platelet activation. PDGFs are disulfide-linked dimers. The subunits of the PDGF dimers are homologous polypeptides designated PDGF-A and PDGF-B chains. Natural PDGFs can exist either as homodimers (PDGF-AA, PDGF-BB) or heterodimers (PDGF-AB). Two splice variants exist for the A-chain (211AA for the long isoform, 196AA for the most abundant short isoform), and C-terminal proteolytic processing apparently occurs for the B-chain (and possibly the A-chain) [10-12]. A-chain long isoform and B-chain contain a cell retention signal at the C-term end, which must be removed in order to release a freely circulating PDGF [13-16]. Two distinct human PDGF receptor transmembrane binding proteins have been identified [17,18].

Methamphetamine abuse

Methamphetamine abuse is a major problem in the United States, as it increases spreads from Western parts of the country to other parts. With its root in the Hawaii, it has gradually spread to the Southern and Mid-west part of the states; and is increasingly associated with unsafe and frivolous behaviors that predispose to transmission of infectious diseases like hepatitis B and C, and even the dreaded virus, HIV.   Of course, the later condition makes it more worrisome for the government, health care workers and Drug agency. It is associated with brain damage, serious cardiovascular disorder, behavioral changes, psychotic symptoms, depression, and deleterious effects in pregnant women. This is a situation where an individual consumes methamphetamine in quantities that are above a therapeutic abuse, without prescription, and for unsolicited personal gains. It presents with short term gains such as euphoria accompanied by rush, high level of activity and increased attention. Methamphetamine is used as therapeutic drug in attention deficit syndrome, and is used to treat narcolepsy, a sleep disorder. Methamphetamine is a Schedule II stimulant. This implies that it had a high addiction tendency and increased potential for abuse. Although it is only available through a prescription that can not be refilled, it is abused by many within the country. Most of these are man aged 18-25white. Etiology The cause of this abuse can not be divorced fro the use of drug for personal or group work. In most cases of abuses [ if not all], methamphetamine is taken as a   neuroactive stimulant to produce short term effects in the individual. Such effects include: euphoria, rush, increase rate of breathing, Increased attention and concentration, Increased activity and wakefulness, reduced appetite and decreased fatigue. It also increases libido. These short term advantages are associated with a good feeling in the user. Besides, it does not last long enough, and as a compensatory mechanism, methamphetamine drub users and chronic abuser engage in continual use of drug, increased consumption frequency. Sometimes, they take high dose of the drug to increase the effect of the drug on their behavior such as improved sexual performance, better attention and increased tendency to work better and more effectively. Methamphetamine comes in a variety of forms. It can be smoked, snorted, injected, or orally ingested. The method that is adopted by a region depends on the cultural behaviour with respect to other abused drugs and the pattern of choice has changed over time. Of these methods, smoking is commonest because of its faster rate of absorption into the brain to produce the desired effects. One other factor that contributes to Methamphetamine abuse is that it is e readily available at local clandestine laboratories. Although it is manufactured by foreign specialized laboratories, the ingredients for its manufacture are readily available over the counter at affordable prices; as a result, it is produced for local use. This contributes greatly to its widespread use. Pathogenesis Methamphetamine is similar to amphetamine but they do not share essentially the same properties of site of action. It is particularly similar to dopamine structurally. Its primary site of action is the brain.   Although t shares certain similar behavioral and physiological effects with cocaine, it is different from it in its mechanism of action. It has a high retention rate in the body. This implies that is not readily eliminated from the system via excretion or detoxification in the liver. Since its primacy site of action is the brain, its absorption and long stay in there increase its stimulant action. Central to this action is the fact it increases the levels of the brain chemical dopamine. Dopamine is a neurotransmitter that is involved in emotional motivation, pleasure, and motor function.   Methamphetamine blocks dopamine re-uptake, while increasing the release of dopamine, leading to much higher concentrations in the synapse, which can be toxic to nerve terminals. This has an implication in chronic abusers, their increased frequency of consumption or ingestion of higher concentration potentates these effects and makes dopamine readily available for its deleterious effects on neurons. Clinical Features The symptoms of methamphetamine abuse and sign elicited on examination arise from the euphoria of short term effect, and the toxic effects of dopamine by virtue of long term use. The short term effects have been mentioned earlier. The long term effects are usually negative: one of such is addiction. Association with chronic consumption of the methamphetamine is increased tolerance for the substance. This creates a preparatory ground for addiction. Other symptoms seen in chronic abusers of methamphetamine include anxiety, confusion, insomnia, mood disturbances, and violent behavior. They also can display a number of psychotic features, including paranoia, visual and auditory hallucinations, and delusions.   Memory Loss, Aggressive or violent behavior, Mood disturbances, severe dental problems, Weight loss also form part of features seen in this category of people. Treatment The alarming rate of spread of methamphetamine indulgence across the nations is worrisome for health care providers. It is equally a headache for every member of the community interested in safe sexual behavior, peace and progress; those averse towards violence and communal clashes which have been associated with methamphetamine abuse. In the midst of this sad picture emerges the god news that methamphetamine abuse can both be prevented and more interestingly treated. Since the disorder includes brain damage which presents in functional and behavioral disturbances, the treatment options available are targeted at these. Treatment of methamphetamine intoxication is primarily supportive. Treatment of methamphetamine abuse is behavioral; cognitive behavior therapy, contingency management, and the Matrix Model have proven effective. Treatments by use of drugs are under investigation. REFERENCES Winslow BT, Voorhees KI, Pehl KA., Methamphetamine abuse. Swedish Medical Center Family Medicine Residency, Littleton, Colorado 80121, USA. http://www.drugabuse.gov/about/organization/cewg/pubs.html. http://www.nida.nih.gov/ResearchReports/Methamph Injury associated with methamphetamine use: A review of the literature Hawaii Med J. 1997;56:34–6, 44. [PubMed]; Murray JB. Psychophysiological aspects of amphetamine-methamphetamine abuse. J Psychol. 1998;132:227–237. †¦ www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1448174 Psychophysiological aspects of amphetamine-methamphetamine abuse. From: The Journal of Psychology | Date: 3/1/1998 | Author: Murray, John B. †¦ www.encyclopedia.com/doc/1G1-20565391.html Thomas Ernst, PhD, Linda Chang, MD, Maria Leonido–Yee, MD and Oliver Speck, PhD Evidence for long-term neurotoxicity associated with methamphetamine abuse http://www.neurology.org/cgi/content/abstract/54/6/1344 Methamphetamine Abuse During Pregnancy: Outcome and Fetal Effects BERTIS B. LITTLE, MA, PhD, LAURA M. SNELL, MPH and LARRY C. GILSTRAP, III, MD ttp://acogjnl.highwire.org/cgi/content/abstract/72/4/541   

Comparing Canadian and American Government essays

Comparing Canadian and American Government essays The governments of Canada and the United States are theoretically based on the political system of democracy. In the United States, their particular system of checks and balances severely disrupts the operations of the government. In addition to this, the American electoral process does not operate in a way where individual's interests are the main focus. In Canada, not only is our electoral system more democratic than that of the United States, but our system of government, including checks and balances, ensures a smoother running government which is more able to fairly govern the nation. The Canadian and American executive branches differ in a way which allows Canada to make executive decisions with much more foresight into future ramifications than our United States counterparts. Furthermore, the Canadian legislative branch functions much more fairly than that of the United States. The Canadian government is a more democratic one than the United States government given their syst em of checks and balances, their electoral process and the influence of the people on the legislative and executive branches. The checks and balances system in governments allows certain branches to validate or ensure decisions made by other branches are just. For example, in the United States, the Supreme Court decides whether or not legislation is constitutional. In Canada, the Governor General, under extreme circumstances, may protect the people from a Prime Minister who chooses to make unjust decisions by refusing powers to the Prime Minister. In the United States, the Head of State cannot do this because they are the same person. The Canadian system of checks and balances is less direct and fixed than that of the United States. Canada's checks and balances lie within our idea ofresponsible government?. This is more of a safety precaution than a system. The cabinet is the official ruling body; however, it is not free from the House of Commons. When t...

AMERICAN LITERARY EXPERIENCE Essays - Stephen King, Free Essays

AMERICAN LITERARY EXPERIENCE Essays - Stephen King, Free Essays AMERICAN LITERARY EXPERIENCE DERYA KOLSDAL ELA LOZINSKI 15 FEBRUARY 1999 IT Stephen King is the author of more than thirty worldwide bestseller. Much of his work has made its way to movie and television screens around the world. Stephen King lives in Bangor, Maine, with his wife, the novelist Tabitha King. He refuses to go into the cellar of his home, having come to believe that a velociraptor is waiting for him under the stairs by the fusebox with its eyes gleaming and its nasty little claws outstretched. The reason he writes horror, ?I?ve always written horror...because it?s a kind of psychological protection. It?s like drawing a magic circle around myself and my family. My mother always used to say,?If you think the worst, it can?t come true? I know that?s only a superstition, but I?ve always believed that if you think the very worst, then, no mattered things get (and in my heart I?ve always been convince that they can get pretty bad), they?ll never get as bad as that. If you write a novel where the bogeyman gets somebody else?s children, maybe they?ll never get your own children...? His full name is Stephen Edwing King ,he is marry with Tabitha Spruce, whom he met at the University of Maine at Orono.He has three childrens, Owen Phillip, Joseph Hillstrom and Naomi Rachel. When he was three, King's merchant seaman father went to get a pack of cigarettes and was never seen again. Sometime in 1959/60 King discovered a box of science-fiction and horror books at an aunt's house,and he start to write short stories. Between 1971 and 1973 King taught English at Hampden Academy, living in a trailer and writing for magazines as an extra source of income.In 1973 he became a full-time writer, publishing Carrie. After several moves, he reached Bangor, Maine in 1980. In the words that grace so many of his books... "He lives with his wife and their three children in Bangor, in Maine, his home state and the place where he feels he really belongs?. His books often focus on evil and the result that fear imposes on people. It deals with several children who have a bit of a trouble with a long-living entity who goes on a killing spree every 27 years... They try desperately to kill it and think they succeeded as children... as they are older they find out that the thing has returned... and they must defeat it once again. They come back to Derry to destroy the evil (it). This time they manage to make absolutely sure that they kill IT.Finally they kill the IT.Well each of them leave Derry, and totally forgets anything that happened. IT was a kind of spider at the end of the story. IT is related with Stephen King?s life, he had a lot of problems while on his child hood. He always wanted to forget the past and in story he made his characters to forget what happened.he can?t forget the past and he wants to show himself that he can forget the bad thing if he really want to forget. On the beginning of the story he show the children like a bunch of losers, other kids don?t like them ,they always mass around them. Also a lot of kid mass around him when he was a little alone kid,he wanted to make friends but no one did like him.he tell the hard thing for the characters weary well because he had the same experiences. In the story he tell us about his childhood under different names. Stephen King believes medic, and he has a lot of fears.All most his all books he use magic ,he thinks that magic is exist.Once he said that?Kids, fiction is the truth inside the lie, and the truth of this fiction is simple enough: the magic exists?.In the story characters beat the IT with magik,he believes magic so it isn?t hard to imagine that kind of unbelievable things.At the end of the story IT shows her self like an insect ,Stephen King fraids of spider and think that you are fraid of spider what do you use for fraytined things ofcaurse giant spider.He tell the gint spider perfectly because a spider is

International Strategic Management Essay Example | Topics and Well Written Essays - 2750 words

International Strategic Management - Essay Example In this paper, the writer examines the TBL concept, discusses its possible contribution to business and economic development and how it can be useful to policymakers. The writer will also provide some examples of how TBL can be applied to achieve the best results for companies and individuals. By concentrating on detailed investment results – about performance based on interrelated aspects of people, profits, and the planet – TBL reporting can be a vital instrument to support sustainability objectives. Interest in TBL accounting has been intensifying in for-profit, government and non-profit sectors. Many enterprises and non-profit firms have implemented the TBL sustainability model to analyse their results (Bachani and Vradelis, 2012:19). Interestingly, a similar approach has become popular with governments at the federal, state and local jurisdictions. TBL is an accounting model that comprises three aspects of performance: social, financial and environmental. This contradicts traditional reporting models because it comprises environmental and social constraints that can be difficult to allocate effective measurement techniques. The TBL aspects are also popularly known as the three Ps: profits, planet, and people. Years before Elkington conceived the sustainability concept now known as TBL, environmentalists grappled with models of, and measures of, sustainability. Academic fields based on sustainability have increased significantly in the last 30 years. People involved inside and outside academic disciplines who have investigated, and practiced sustainability would concur with Andrew Savitz’s general definition of TBL (Longoni, 2014:43). According to Savitz (2013:15), TBL encapsulates the basis of sustainability by gauging how an organisation’s activities affect the world, including its stockholder and profitability values and its human, environmental and social capital. According to scholars, the problem is not defining TBL;

Research paper Essay Example | Topics and Well Written Essays - 2000 words - 3

Research paper - Essay Example The adoption of the term was in the 20th century and has had a vast application in recognition of human beings that do not fall in the two broad human categories: males and females. In the western society, the field of intersex is very clear in educating people on the various disorders that human beings bear and the efforts that scientists have made in the comprehension of the conditions. Going through the various opinions that scientists, professionals and the general population have regarding the issue is an important step paving way for in depth understanding of the situation. Introduction Many writers in the continent have also made tremendous strides forward in a bid to educate people on the various conditions involved in the field of intersex. Another aspect of the field that has close ties with the main subject is intersex surgery. This is the kind of surgery performed on people with intersex disorder in a bid to accomplish varying purposes. The two main reasons that the surge ry is performed are to either save the life of the person or to address social issues that the person may be facing (Sytsma 106). However, many scientists warn about the issue of genital surgery as research shows that the results got from the surgery are far worse than good on not only the areas under surgery but also the entire body system of the person. Katrina Roen's Views Katrina Roen is a very famous writer who has written many books and articles concerning the area of intersex. She is the writer of one critically analyzed and reviewed article called â€Å"But We Have to Do Something.† The article has had major reviews from the manner in which Katrina focuses on the issues portrayed by various writers in the field of intersex and intersex surgery. She majorly focuses on the issue of cosmetic surgery in the western society in relation to infants atypically sexed. In her publication, she criticizes the rest of the publications stating that the manner in which they feature the female and human body as a whole is not only demining but also bothering the rest of the population. In the 21st century, many changes have been made in the surgical processes carried out, and this has had great benefits to many people. However, Katrina states that these changes should not be a reason for people to always opt for surgery and especially when dealing with young people and infants. Katrina states that the young and infants are rather vulnerable at their ages and getting them through surgery is a rather traumatic process. She goes ahead to state that parents should take responsibility for their actions as anything may happen in the surgical rooms having authorized the procedures. It is not right for children and infants to go through the strenuous surgical processes as they may have a negative impact on their development, and the outcome is never certain (Roen 42). Katrina also states that taking them through the procedures is rather poor as the kids had no approval of undergoing the procedure. She then advises that parents halt such procedures and just wait for their kids to grow up and make their own decisions as to whether they should undergo the surgery or continue living in their conditions. Another factor that she takes into consideration while going around her discussion is about the work published by feminists and their regard to intersex

Analysis report of Shuttle Wagons project Essay

Analysis report of Shuttle Wagons project - Essay Example This happened due to the fact that the safety regime was not defined properly and lacked clarification at the start of the project. Some approvals took longer than expected; the safety regulators did not fully know what the environment of the Channel Tunnel was like because of the Kings Cross Fire incidents which took place in 1987. These are the main considerations of the entire project. Analysis Report of Shuttle Wagons Project Purpose of the Report The task of constructing the shuttle wagons was given to Trans Manche Link who subcontracted other manufacturers to build the wagons. The project faced a lot of business problems and the major problem was the delay in building the shuttle due to several reasons and the approval of safety regulators (Clancy 2008). The purpose of this report is to give comprehensive analytical and evaluative business recommendations and to present solutions to the problems which the Shuttle Wagon Project has faced. In this regard, it is pertinent to addre ss some issues first. Background of the report The Eurotunnel is the biggest infrastructure to be owned and financed privately in the world’s history. ... iven to Trans Manche Link (TML) who in turn subcontracted different manufacturers to build high speed shuttle wagons which were to transport freight as well as passengers to different parts of Europe (Clancy 2008). The project was a combination of two different functions firstly it needed the finance and secondly it needed construction contractors. So naturally there were two groups who were involved in the projects, banks and constructions companies. But despite all that there were a number of equity issues that the project was facing due to the fact that the financial institutions were risking more than they originally planned, a number of things got delayed due to the UK general elections, there were no negotiations on a credit agreement and everything was turning out to be a mess due to the delays (Harris 1996). On top of that there were various shuttle design issues and as there was no concise safety regime plan which developed the shuttle wagons were brought back to be redesign ed according to the safety regulations. Interest on payments was piling up due to the delays and it was getting difficult for the project to determine the profits. Plus there a number of problems gave birth to other problems for example as all the changes which were to be made systematically as the issue was with the product which was the shuttle, it was necessary to change other elements of their design as well which took time. Secondly there were complications in the design of the under car (Rosenberg 2012). The manufacturing of cross related products became complex, the fact that in order to make one element or design one element a number of elements had to also be re designed this caused problems for the technicians and the manufacturers who were already over burdened with the