Crohn's disease is a chronic inflammatory bowel disease characterized by recurrent episodes of intestinal inflammation, primarily manifesting as diarrhea and abdominal pain. Unlike ulcerative colitis, inflammation can occur anywhere in the gastrointestinal tract, though it most frequently affects the ileum and colon, involving all layers of the intestinal wall. Symptoms may be non-specific and progress gradually, often delaying diagnosis. About one-third of patients have colonic disease, another third have ileocolic disease, and the remaining third have isolated ileal disease. Systemic symptoms such as chronic fatigue, weight loss, and low-grade fevers are common. Organs such as the skin and joints can also be affected. Complications can include bowel obstructions, fistulas, nutrition problems, and an increased risk of intestinal cancers.
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity). Sometimes the word is more or less synonymous with poisoning in everyday usage.
Polycythemia is a laboratory finding in which the hematocrit and/or hemoglobin concentration are increased in the blood. Polycythemia is sometimes called erythrocytosis, and there is significant overlap in the two findings, but the terms are not the same: polycythemia describes any increase in hematocrit and/or hemoglobin, while erythrocytosis describes an increase specifically in the number of red blood cells in the blood.
Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affect the patient's immune system. Examples of these extrinsic factors include HIV infection and environmental factors, such as nutrition. Immunocompromisation may also be due to genetic diseases/flaws such as SCID.
Liver disease, or hepatic disease, is any of many diseases of the liver. If long-lasting it is termed chronic liver disease. Although the diseases differ in detail, liver diseases often have features in common.
Pseudocholinesterase deficiency is an autosomal recessive inherited blood plasma enzyme abnormality in which the body's production of butyrylcholinesterase is impaired. People who have this abnormality may be sensitive to certain anesthetic drugs, including the muscle relaxants succinylcholine and mivacurium as well as other ester local anesthetics.
Gene–environment interaction is when two different genotypes respond to environmental variation in different ways. A norm of reaction is a graph that shows the relationship between genes and environmental factors when phenotypic differences are continuous. They can help illustrate GxE interactions. When the norm of reaction is not parallel, as shown in the figure below, there is a gene by environment interaction. This indicates that each genotype responds to environmental variation in a different way. Environmental variation can be physical, chemical, biological, behavior patterns or life events.
Immunotoxicology is the study of the toxicity of foreign substances called xenobiotics and their effects on the immune system. Some toxic agents that are known to alter the immune system include: industrial chemicals, heavy metals, agrochemicals, pharmaceuticals, drugs, ultraviolet radiation, air pollutants and some biological materials. The effects of these immunotoxic substances have been shown to alter both the innate and adaptive parts of the immune system. Consequences of xenobiotics affect the organ initially in contact. Some commonly seen problems that arise as a result of contact with immunotoxic substances are: immunosuppression, hypersensitivity, and autoimmunity. The toxin-induced immune dysfunction may also increase susceptibility to cancer.
Cholesterol 7 alpha-hydroxylase also known as cholesterol 7-alpha-monooxygenase or cytochrome P450 7A1 (CYP7A1) is an enzyme that in humans is encoded by the CYP7A1 gene which has an important role in cholesterol metabolism. It is a cytochrome P450 enzyme, which belongs to the oxidoreductase class, and converts cholesterol to 7-alpha-hydroxycholesterol, the first and rate limiting step in bile acid synthesis.
Public health genomics is the use of genomics information to benefit public health. This is visualized as more effective preventive care and disease treatments with better specificity, tailored to the genetic makeup of each patient. According to the Centers for Disease Control and Prevention (U.S.), Public Health genomics is an emerging field of study that assesses the impact of genes and their interaction with behavior, diet and the environment on the population's health.
ATP-binding cassette, sub-family B member 11 (ABCB11), also known as the bile salt export pump (BSEP), is a protein which in humans is encoded by the ABCB11 gene.
Chronic mucocutaneous candidiasis is an immune disorder of T cells. It is characterized by chronic infections with Candida that are limited to mucosal surfaces, skin, and nails. It can also be associated with other types of infections, such as human papilloma virus. An association with chromosome 2 has been identified.
HIV disease–related drug reaction is an adverse drug reaction caused by drugs used for the treatment of HIV/AIDS.
Human genetic resistance to malaria refers to inherited changes in the DNA of humans which increase resistance to malaria and result in increased survival of individuals with those genetic changes. The existence of these genotypes is likely due to evolutionary pressure exerted by parasites of the genus Plasmodium which cause malaria. Since malaria infects red blood cells, these genetic changes are most common alterations to molecules essential for red blood cell function, such as hemoglobin or other cellular proteins or enzymes of red blood cells. These alterations generally protect red blood cells from invasion by Plasmodium parasites or replication of parasites within the red blood cell.
Complement 3 deficiency is a genetic condition affecting complement component 3 (C3). People can suffer from either primary or secondary C3 deficiency. Primary C3 deficiency refers to an inherited autosomal-recessive disorder that involves mutations in the gene for C3. Secondary C3 deficiency results from a lack of factor I or factor H, two proteins that are key for the regulation of C3. Both primary and secondary C3 deficiency are characterized by low levels or absence of C3.
Copper is an essential trace element that is vital to the health of all living things. In humans, copper is essential to the proper functioning of organs and metabolic processes. Also, in humans, copper helps maintain the nervous system, immune system, brain development, and activates genes, as well as assisting in the production of connective tissues, blood vessels, and energy. The human body has complex homeostatic mechanisms which attempt to ensure a constant supply of available copper, while eliminating excess copper whenever this occurs. However, like all essential elements and nutrients, too much or too little nutritional ingestion of copper can result in a corresponding condition of copper excess or deficiency in the body, each of which has its own unique set of adverse health effects.
Cancer is caused by genetic changes leading to uncontrolled cell growth and tumor formation. The basic cause of sporadic (non-familial) cancers is DNA damage and genomic instability. A minority of cancers are due to inherited genetic mutations. Most cancers are related to environmental, lifestyle, or behavioral exposures. Cancer is generally not contagious in humans, though it can be caused by oncoviruses and cancer bacteria. The term "environmental", as used by cancer researchers, refers to everything outside the body that interacts with humans. The environment is not limited to the biophysical environment, but also includes lifestyle and behavioral factors.
Addiction vulnerability is an individual's risk of developing an addiction during their lifetime. There are a range of genetic and environmental risk factors for developing an addiction that vary across the population. Genetic and environmental risk factors each account for roughly half of an individual's risk for developing an addiction; the contribution from epigenetic risk factors to the total risk is unknown. Even in individuals with a relatively low genetic risk, exposure to sufficiently high doses of an addictive drug for a long period of time can result in an addiction. In other words, anyone can become an individual with a substance use disorder under particular circumstances. Research is working toward establishing a comprehensive picture of the neurobiology of addiction vulnerability, including all factors at work in propensity for addiction.
Alcohol intolerance is due to a genetic polymorphism of the aldehyde dehydrogenase enzyme, which is responsible for the metabolism of acetaldehyde. This polymorphism is most often reported in patients of East Asian descent. Alcohol intolerance may also be an associated side effect of certain drugs such as disulfiram, metronidazole, or nilutamide. Skin flushing and nasal congestion are the most common symptoms of intolerance after alcohol ingestion. It may also be characterized as intolerance causing hangover symptoms similar to the "disulfiram-like reaction" of aldehyde dehydrogenase deficiency or chronic fatigue syndrome. Severe pain after drinking alcohol may indicate a more serious underlying condition.
The following outline is provided as an overview of and topical guide to concepts related to infectious diseases in humans.
