Organ transplantation in the context of "Intestinal transplant"

Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals, as model organisms, in experiments that seek answers to scientific and medical questions. This approach can be contrasted with field studies in which animals are observed in their natural environments or habitats. Experimental research with animals is usually conducted in universities, medical schools, pharmaceutical companies, defense establishments, and commercial facilities that provide animal-testing services to the industry. The focus of animal testing varies on a continuum from pure research, focusing on developing fundamental knowledge of an organism, to applied research, which may focus on answering some questions of great practical importance, such as finding a cure for a disease. Examples of applied research include testing disease treatments, breeding, defense research, and toxicology, including cosmetics testing. In education, animal testing is sometimes a component of biology or psychology courses.

Research using animal models has been central to most of the achievements of modern medicine. It has contributed to most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. The results have included the near-eradication of polio and the development of organ transplantation, and have benefited both humans and animals. From 1910 to 1927, Thomas Hunt Morgan's work with the fruit fly Drosophila melanogaster identified chromosomes as the vector of inheritance for genes, and Eric Kandel wrote that Morgan's discoveries "helped transform biology into an experimental science". Research in model organisms led to further medical advances, such as the production of the diphtheria antitoxin and the 1922 discovery of insulin and its use in treating diabetes, which was previously fatal. Modern general anaesthetics such as halothane were also developed through studies on model organisms, and are necessary for modern, complex surgical operations. Other 20th-century medical advances and treatments that relied on research performed in animals include organ transplant techniques, the heart-lung machine, antibiotics, and the whooping cough vaccine.

A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Model organisms are widely used to research human disease when human experimentation would be unfeasible or unethical. This strategy is made possible by the common descent of all living organisms, and the conservation of metabolic and developmental pathways and genetic material over the course of evolution.

Research using animal models has been central to most of the achievements of modern medicine. It has contributed most of the basic knowledge in fields such as human physiology and biochemistry, and has played significant roles in fields such as neuroscience and infectious disease. The results have included the near-eradication of polio and the development of organ transplantation, and have benefited both humans and animals. From 1910 to 1927, Thomas Hunt Morgan's work with the fruit fly Drosophila melanogaster identified chromosomes as the vector of inheritance for genes, and Eric Kandel wrote that Morgan's discoveries "helped transform biology into an experimental science". Research in model organisms led to further medical advances, such as the production of the diphtheria antitoxin and the 1922 discovery of insulin and its use in treating diabetes, which had previously meant death. Modern general anaesthetics such as halothane were also developed through studies on model organisms, and are necessary for modern, complex surgical operations. Other 20th-century medical advances and treatments that relied on research performed in animals include organ transplant techniques, the heart-lung machine, antibiotics, and the whooping cough vaccine.

The regulatory T cells (Tregs /ˈtiːrɛɡ/ or T_reg cells), formerly known as suppressor T cells, are a subpopulation of T cells that modulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease. T_reg cells are immunosuppressive and generally suppress or downregulate induction and proliferation of effector T cells. T_reg cells express the biomarkers CD4, FOXP3, and CD25 and are thought to be derived from the same lineage as naïve CD4 cells. Because effector T cells also express CD4 and CD25, T_reg cells are very difficult to effectively discern from effector CD4, making them difficult to study. Research has found that the cytokine transforming growth factor beta (TGF-β) is essential for T_reg cells to differentiate from naïve CD4 cells and is important in maintaining T_reg cell homeostasis.

Mouse models have suggested that modulation of T_reg cells can treat autoimmune disease and cancer and can facilitate organ transplantation and wound healing. Their implications for cancer are complicated. T_reg cells tend to be upregulated in individuals with cancer, and they seem to be recruited to the site of many tumors. Studies in both humans and animal models have implicated that high numbers of T_reg cells in the tumor microenvironment is indicative of a poor prognosis, and T_reg cells are thought to suppress tumor immunity, thus hindering the body's innate ability to control the growth of cancerous cells. Immunotherapy research is studying how regulation of T cells could possibly be utilized in the treatment of cancer.

Hematopoietic stem-cell transplantation (HSCT) is the transplantation of multipotent hematopoietic stem cells, usually derived from bone marrow, peripheral blood, or umbilical cord blood, in order to replicate inside a patient and produce additional normal blood cells. HSCT may be autologous (the patient's own stem cells are used), syngeneic (stem cells from an identical twin), or allogeneic (stem cells from a donor).

It is most often performed for patients with certain cancers of the blood or bone marrow, such as multiple myeloma, leukemia, some types of lymphoma and immune deficiencies. In these cases, the recipient's immune system is usually suppressed with radiation or chemotherapy before the transplantation. Infection and graft-versus-host disease are major complications of allogeneic HSCT.

Kaposi's sarcoma (KS) is a type of cancer that can form masses on the skin, in lymph nodes, in the mouth, or in other organs. The skin lesions are usually painless, purple, and may be flat or raised. Lesions can occur singly, multiply in a limited area, or may be widespread. Depending on the sub-type of disease and level of immune suppression, KS may worsen either gradually or quickly. Except for classic KS where there is generally no immune suppression, KS is caused by a combination of immune suppression (such as HIV/AIDS) and infection by Human herpesvirus 8 (HHV8 – also called KS-associated herpesvirus (KSHV)).

Classic, endemic, immunosuppression therapy-related (also known as iatrogenic), and epidemic (also known as AIDS-related) sub-types are all described. Classic KS tends to affect older men in regions where KSHV is highly prevalent (Mediterranean, Eastern Europe, Middle East), is usually slow-growing, and most often affects only the legs. Endemic KS is most common in Sub-Saharan Africa and is more aggressive in children, while older adults present similarly to classic KS. Immunosuppression therapy-related KS generally occurs in people following organ transplantation and mostly affects the skin. Epidemic KS occurs in people with AIDS and many parts of the body can be affected. KS is diagnosed by tissue biopsy, while the extent of disease may be determined by medical imaging.

Organ procurement (also called surgical recovery) is a surgical procedure that removes organs or tissues for reuse, typically for organ transplantation.

Ex vivo (Latin for 'out of the living') refers to biological studies involving tissues, organs, or cells maintained outside their native organism under controlled laboratory conditions. By carefully managing factors such as temperature, oxygenation, nutrient delivery, and perfusing a nutrient solution through the tissue's vasculature, researchers sustain function long enough to conduct experiments that would be difficult or unethical in a living body. Ex vivo models occupy a middle ground between in vitro (lit. 'in the glass') models, which typically use isolated cells, and in vivo (lit. 'in the living') studies conducted inside living organisms.

Ex vivo platforms support pharmacologic screening, toxicology testing, transplant evaluation, developmental biology, and investigations of disease-mechanism research across medicine and biology, from cardiology and neuroscience to dermatology and orthopedics. Because they often use human tissues obtained from clinical procedures or biobanks, they can reduce reliance on live-animal experimentation; their utility, however, is limited by finite viability, incomplete systemic integration, and post-mortem biochemical changes that accumulate over time. The earliest perfusion studies were conducted in the mid-19th century, and subsequent advances in sterilization, imaging, and microfluidics have facilitated broader adoption into the 20th and 21st centuries. Regulatory oversight depends on specimen origin: human ex vivo research is subject to informed consent, whereas animal-derived models fall under institutional animal care guidelines.

Autotransplantation is the transplantation of organs, tissues, or even particular proteins from one part of the body to another in the same person (auto- meaning "self" in Greek).

The autologous tissue (also called autogenous, autogeneic, or autogenic tissue) transplanted by such a procedure is called an autograft or autotransplant.

Cross-matching or crossmatching is a test performed before a blood transfusion as part of blood compatibility testing. Normally, this involves adding the recipient's blood plasma to a sample of the donor's red blood cells. If the blood is incompatible, the antibodies in the recipient's plasma will bind to antigens on the donor red blood cells. This antibody-antigen reaction can be detected through visible clumping or destruction of the red blood cells, or by reaction with anti-human globulin. Along with blood typing of the donor and recipient and screening for unexpected blood group antibodies, cross-matching is one of a series of steps in pre-transfusion testing. In some circumstances, an electronic cross-match can be performed by comparing records of the recipient's ABO and Rh blood type against that of the donor sample. In emergencies, blood may be issued before cross-matching is complete. Cross-matching is also used to determine compatibility between a donor and recipient in solid organ transplantation including heart/lung transplation.

Alexis Carrel (French: [alɛksi kaʁɛl]; 28 June 1873 – 5 November 1944) was a French surgeon and biologist who spent most of his scientific career in the United States. He was awarded the Nobel Prize in Physiology or Medicine in 1912 for pioneering vascular suturing techniques. He invented the first perfusion pump with Charles Lindbergh opening the way to organ transplantation. Carrel was also a pioneer in tissue culture, transplantology and thoracic surgery. He is known for his leading role in implementing eugenic policies in Vichy France.

Chagas disease, also known as American trypanosomiasis, is a tropical parasitic disease caused by Trypanosoma cruzi. It is spread mostly by insects in the subfamily Triatominae, known as "kissing bugs". The symptoms change throughout the infection. In the early stage, symptoms are typically either not present or mild and may include fever, swollen lymph nodes, headaches, or swelling at the site of the bite. After four to eight weeks, untreated individuals enter the chronic phase of disease, which in most cases does not result in further symptoms. Up to 45% of people with chronic infections develop heart disease 10–30 years after the initial illness, which can lead to heart failure. Digestive complications, including an enlarged esophagus or an enlarged colon, may also occur in up to 21% of people, and up to 10% of people may experience nerve damage.

T. cruzi is commonly spread to humans and other mammals by the kissing bug's bite wound and the bug's infected feces. The disease may also be spread through blood transfusion, organ transplantation, consuming food or drink contaminated with the parasites, and vertical transmission (from a mother to her baby). Diagnosis of early disease is by finding the parasite in the blood using a microscope or detecting its DNA by polymerase chain reaction. Chronic disease is diagnosed by finding antibodies for T. cruzi in the blood.

Candidiasis is a fungal infection due to any species of the genus Candida (a yeast). When it affects the mouth, in some countries it is commonly called thrush. Signs and symptoms include white patches on the tongue or other areas of the mouth and throat. Other symptoms may include soreness and problems swallowing. When it affects the vagina, it may be referred to as a yeast infection or thrush. Signs and symptoms include genital itching, burning, and sometimes a white "cottage cheese-like" discharge from the vagina. Yeast infections of the penis are less common and typically present with an itchy rash. Very rarely, yeast infections may become invasive, spreading to other parts of the body. This may result in fevers, among other symptoms. Finally, candidiasis of the esophagus is an important risk factor for contracting esophageal cancer in individuals with achalasia.

More than 20 types of Candida may cause infection with Candida albicans being the most common. Infections of the mouth are most common among children less than one month old, the elderly, and those with weak immune systems. Conditions that result in a weak immune system include HIV/AIDS, the medications used after organ transplantation, diabetes, and the use of corticosteroids. Other risk factors include during breastfeeding, following antibiotic therapy, and the wearing of dentures. Vaginal infections occur more commonly during pregnancy, in those with weak immune systems, and following antibiotic therapy. Individuals at risk for invasive candidiasis include low birth weight babies, people recovering from surgery, people admitted to intensive care units, and those with an otherwise compromised immune system.

The Aberdeen Royal Infirmary (ARI) is the largest hospital in the Grampian area, located on the Foresterhill site in Aberdeen, Scotland. The ARI is a teaching hospital with around 900 inpatient beds, offering tertiary care for a population of over 600,000 across the north of Scotland. It offers all medical specialities with the exception of heart and liver transplants. It is managed by NHS Grampian.

Organ donation is defined as the process when a person authorizes an organ of their own to be removed and transplanted to another person, legally, either by consent while the donor is alive, through a legal authorization for deceased donation made prior to death, or for deceased donations through the authorization by the legal next of kin.

Donation may be for research or, more commonly, healthy transplantable organs and tissues may be donated to be transplanted into another person.

Thymus transplantation is a form of organ transplantation where the thymus is moved from one body to another. It is used in certain immunodeficiencies, such as DiGeorge Syndrome.