By W. Marlo. Antioch University Yellow Springs OH.
Hal Anger (also a Donner man) invented in John Lawrence Hal Anger 1958 the gamma-camera – also called Anger (1904 – 1991) (1920 – 2005) camera discount 4mg periactin with amex allergy symptoms kiwi. This is also called “Anger camera” and consisted of a large fat scintilla- tion crystal and a number of photomultipliers generic periactin 4 mg online allergy shots three times a week. They used I-131 labeled insulin to measure the reaction between an antigen and antibody. David Kuhl 193 Some of the isotopes used in nuclear medicine The use of radioactive isotopes in research and medicine can be divided in three groups. Isotopes used as tracers A radioactive isotope attached to an important molecule can tell where it is. Isotopes emitting g-rays are easily observed, but also pure b-emitters like H–3 (tritium) and C–14 can be used. Thus, Melvin Calvin used C–14 to the exploration of photosynthetic carbon dioxide reduction. The Hershey – Chase experiment A very well known experiment with radioactive tracers was the Hershey– Chase experiment from 1952. Alfred Hershey and Martha Chase used the isotopes P–32 (b-emitter with half-life 14 days) and S–35 (b-emitter with half-life 87 days). Alfred Hershey (1908 – 1997) was the principal investiga- Numerous experiments within bio- tor, whereas Martha Chase (1927 – 2003) was the lab. Isotopes in radiation therapy In radiation therapy the purpose is to irradiate cancer cells to death and let the normal cells survive. Radium (Ra–226) was used from the beginning, both for teletherapy and as im- plants in brachytherapy. Attached to compounds (monoclonal antibodies) the isotope can be transported to the the cancer cells. Isotopes for diagnostic purposes Several isotopes emitting g-rays can, and have been used for diagnostic purposes. For example, I–131 will be accumulated in the thyroid and can via a gamma camera give information about sicknesses in the thyroid. We have pointed out before that the isotope most often used for medical information is Tc–99m. Thus, after the b-particle emission the newly formed technetium isotope is in a socalled “meta- stable” state. If we could isolate this metastable isotope it would be perfect for medical use, since the isotope would only emit a g-photon with no contamination from b-particles. Decay scheme for Mo-99 Mo–99 67 h The decay of Mo–99 results in a metastable nucleus – de- noted Tc–99m. By emitting a g- photon it ends up in Tc–99 which is radioactive with a Tc–99 halfife of 213 000 years. The compound is rinsed with physi- ological saline, and the Tc-99m that has been formed follows the water – it is like “milking”. The next step is to hook on this isotope to compounds that can bring it to particular places in the body that can be studied. More than 30 compounds based on Tc-99m have been made for imaging and functional studies of the brain, myocardium, thyroid, lungs, liver, gallbladder, kidneys, skeleton, blood and tumors. Tc-99m emits γ-radiation with an energy of 140 keV, which readily escapes the body and is easily measurable. From a physicists point of view it is probably the technique developed to observe the distribution of radioactivity that is the most interesting – whereas from a medical point of view it is the diagnostic power that is the most interesting. Ben Cassen and Hal Anger The technique with the radioactive isotopes in medical diagnostics started in the 1950s when Benedict Cassen invented the rectilinear scanner and in 1958 with the g-camera (or Anger camera). Blahd A picture of Hal Anger (1920 – 2005) and Benedict Cassen (1902 – 1972) at the International Confer- ence on Peaceful Uses of Atomic Energy in Geneva, Switzerland, in 1955. It can be mentioned that the “Society of Nuclear Medicine” every second year since 1994 give out a prize in honor of Benedict Cassen (The Benedict Cassen prize) for outstanding achievements in nuclear medicine. The illustration to the right demonstrate the technique introduced by Benedict Cassen. He assembled the frst auto- mated scanning system that was com- prised of a motor driven scintillation de- tector coupled to a relay printer. After the ini- tial studies, it was an extensive use of the scanning system for thyroid imaging during the early 1950s. Cassen’s devel- opment of the rectilinear scanner was a defning event in the evolution of clinical nuclear medicine.
So before microbes could be used to benefit mankind discount periactin 4 mg line allergy forecast las vegas, mankind had to prove they existed buy periactin 4 mg online allergy symptoms quiz. Pasteur, through experiments with nutrient broths, rejected the common thought that microbes appeared spontaneously and that they traveled through the air causing diseases in silkworms as well as spoiling beverages such as wine, beer, and milk. Though not the first to propose germ theory of disease, Pasteur accepted the hypothesis of germ theory scientifically and was able to persuade much of Europe of the validity of his findings (Tiner, 1991). This understanding began to explain many historical phenomena, notably instances in India and China where people were vaccinated against the smallpox disease using powdered scabs of patients infected with smallpox (Temple, 1986). Over time, the development of vaccinations was used to help protect against a wide array of diseases such as measles, mumps, and hepatitis. Microorganisms are widely used in modern medicine, and this is because microbes are an amazingly diverse population. Microbes consist of bacteria, fungi, archaea, protists, plants which are invisible to the naked eye, and plankton. Some scientists consider viruses to be microbes, though it is debatable due to the fact that viruses can’t reproduce independently of a live host. Within this wide spectrum of microbes, there is an amazing amount of chemical and physical diversity among populations. Though there is a large diversity of the potential of microbes in society, the main focus of this study will be on microbes in medicine. Bacteria are unicellular organisms of the kingdom Monera, and typically contain a cell wall composed of peptidoglycan. Bacteria are especially useful in medicine because of their short reproduction cycle (Escherichia Coli has been known to divide in 40 minutes) and the ease with which they can be genetically manipulated. Scientists have used bacterial genomic manipulation to understand more complex organisms through the understanding of bacterial gene and enzyme function, as well as metabolic pathway. Fungi on the other hand are eukaryotic organisms of the kingdom Fungi, containing species such as mushrooms, yeasts, and molds. Fungi are distinct in character in that their cell wall is composed of the polysaccharide chitin, not peptidoglycan or cellulose which animals and plants, respectively, have. Fungi share many characteristics with other eukaryotes such as membrane bound organelles and have similar functional processes. In relation to animals fungi do not possess chloroplasts, however similarly to plants fungi maintain a cell wall, vacuoles, and may produce by both sexual and/or asexual means. The development of a delivery capsule was a necessary advancement in the treatment of cancer. Chemotherapy, the most common method of cancer treatment, is targeted not only for cancer cells but all rapidly dividing cells. This includes intestinal cells, bone marrow, mucosal cells, and stomach cells, among others. The use of chemotherapy as cancer treatment suppresses the immune system and may cause sickness and even other cancers, which is why site-specific delivery is so important in modern medicine. For one, a gene known as invasin was added allowing the bacteria to pass through the membrane of human cells, something it was previously unable to. Secondly, the researchers added a gene called listeriolysin O, a gene which turns the bacteria into a sort of ticking time bomb and causes the gene to spill its contents once it has entered the membrane of its destination cell. By use of testing in mouse tumors the combination was successful in killing more than 90% of cancer cells present, a very impressive amount. The proteins act to specifically target the claudin-3 and claudin-4 epithelial receptors present in breast, prostate, lung, endometrial, thyroid, and pancreatic cancer tumors. Clostridium is ideal for acting as a target inside of tumors since it is anaerobic and thrives in the hypoxic environment which is present on the interior of tumors. Doxorubicin, when injected encapsulated into mice with colorectal tumors caused the death of each mouse within two weeks. However when doxorubicin was encapsulated in liposomes (Figure 1) and Clostridium was present in the colorectal tumors, healthy cells were not targeted by the drug, and the anti-cancer agent was successful in eradicating a majority of the tumors.
Economies are globalizing buy 4 mg periactin with mastercard allergy shots on nhs, people are more likely to live in cities generic 4mg periactin with amex allergy medicine enlarged prostate, and technology is evolving rapidly. Demographic and family changes mean there will be fewer older people with families to care for them. People today have fewer children, are less likely to be married, and are less likely to live with older generations. By 2050, this number is expected to fell with surprising speed in many less developed nearly triple to about 1. Between 2010 and 2050, the number of older Most developed nations have had decades to people in less developed countries is projected to adjust to their changing age structures. In contrast, many less This remarkable phenomenon is being driven developed countries are experiencing a rapid by declines in fertility and improvements in increase in the number and percentage of older longevity. With fewer children entering the people, often within a single generation (Figure population and people living longer, older 2). For example, the same demographic aging people are making up an increasing share of the that unfolded over more than a century in total population. The Speed of Population Aging Time required or expected for percentage of population aged 65 and over to rise from 7 percent to 14 percent Source: Kinsella K, He W. In some countries, the sheer number of people entering older ages will challenge national infrastructures, particularly health systems. By the middle of this century, there could be 100 million Chinese over the age of 80. This is an amazing achievement considering that there were fewer than 14 million people this age on the entire planet just a century ago. Growth of the Population Aged 65 and Older in India and China: 2010-2050 Source: United Nations. Humanity’s Aging 5 Living Longer The dramatic increase in average life expectancy pathways. Less developed to noncommunicable diseases and chronic regions of the world have experienced a steady conditions. Even These improvements are part of a major earlier, better living standards, especially transition in human health spreading around more nutritious diets and cleaner drinking the globe at different rates and along different water, began to reduce serious infections and prevent deaths among children. Research for more recent periods shows a surprising and continuing improvement in life expectancy among those aged 80 or above. The progressive increase in survival in these oldest age groups was not anticipated by demographers, and it raises questions about how high the average life expectancy can realistically rise and about the potential length of the human lifespan. While some experts assume that life expectancy must be approaching an upper limit, 6 Global Health and Aging Figure 4. Living Longer 7 data on life expectancies between 1840 and 2007 global level, the 85-and-over population is show a steady increase averaging about three projected to increase 351 percent between 2010 months of life per year. The country with the and 2050, compared to a 188 percent increase for highest average life expectancy has varied over the population aged 65 or older and a 22 percent time (Figure 4). So far there is little evidence that life to increase 10-fold between 2010 and 2050. In many decreases in mortality rates among the oldest countries, the oldest old are now the fastest old. Percentage Change in the World’s Population by Age: 2010-2050 Source: United Nations, World Population Prospects: The 2010 Revision. Demographers and epidemiologists describe this Evidence from the multicountry Global Burden shift as part of an “epidemiologic transition” of Disease project and other international characterized by the waning of infectious and epidemiologic research shows that health acute diseases and the emerging importance of problems associated with wealthy and aged chronic and degenerative diseases. High death populations affect a wide and expanding rates from infectious diseases are commonly swath of world population. Over the next associated with the poverty, poor diets, and 10 to 15 years, people in every world region limited infrastructure found in developing will suffer more death and disability from countries. Although many developing countries such noncommunicable diseases as heart still experience high child mortality from disease, cancer, and diabetes than from infectious and parasitic diseases, one of the Figure 6. The Increasing Burden of Chronic Noncommunicable Diseases: 2008 and 2030 Source: World Health Organization, Projections of Mortality and Burden of Disease, 2004-2030. In direct bearing on the development of risk factors for 2008, noncommunicable diseases accounted for an adult diseases—especially cardiovascular diseases.