For the eye of a cyclone, see eye (cyclone).
The eye is a round organ for sensinglight so animals can see. About 97 percent of animals have eyes. Image-resolving eyes are present in cnidaria, molluscs, vertebtates,annelids and arthropods.
In mammals, two kinds of cells, rods and cones, allow sight by sending signals through the optic nerve to the brain.
Some animals can see light that humans cannot see. They can see ultraviolet or infrared light.
The lens on the front part of the eye acts like a camera lens. It can be pulled flatter by muscles inside the eye, or allowed to become rounder. As some people get older, they may not be as able to do this perfectly. Many people are born with other small problems or get them later in life, and they may need eyeglasses (or contact lenses) to fix the problem.
Types of eye[change | change source]
Today, ten different types of eyes are known. Most ways of capturing an image have evolved at least once.
One way to categorize eyes is to look at the number of "chambers". Simple eyes are made of only one concave chamber, perhaps with a lens. Compound eyes have many such chambers with their lenses on a convexsurface.
Eyes also can be grouped according to how the photoreceptor is made. Photoreeptors are either cillated, or rhabdomic. and some annelids possess both.
Simple eyes[change | change source]
Pit eyes[change | change source]
Pit eyes are set in a depression in the skin. This reduces the angles at which light can enter. It allows the organism to say where the light is coming from.
Such eyes can be found in about 85% of phyla. They probably came before the development of more complex eyes. Pit eyes are small. They are made of up to about hundred cells, covering about 100 µm. The directionality can be improved by reducing the size of the opening, and by putting a reflective layer behind the receptor cells.
Pinhole eye[change | change source]
The pinhole eye is an advanced form of pit eye. It has several bits, most notably a small aperture and deep pit. Sometimes, the aperture can be changed. It is only found in the Nautilus. Without a lens to focus the image, it produces a blurry image. Consequently, nautiloids can not discriminate between objects with a separation of less than 11°. Shrinking the aperture would produce a sharper image, but let in less light.
Spherical lensed eye[change | change source]
The resolution of pit eyes can be improved a lot by adding a material to make a lens. This will reduce the radius of the blurring, and increase the resolution that can be achieved. The most basic form can still be seen in some gastropods and annelids. These eyes have a lens of one refractive index. It is possible to get a better image with materials that have a high refractive index which decreases towards the edges. This decreases the focal length and allows a sharp image to form on the retina.
This eye creates an image that is sharp enough that motion of the eye can cause significant blurring. To minimize the effect of eye motion while the animal moves, most such eyes have stabilizing eye muscles.
The ocelli of insects have a simple lens, but their focal point always lies behind the retina.They can never form a sharp image. This limits the function of the eye. Ocelli (pit-type eyes of arthropods) blur the image across the whole retina. They are very good at responding to rapid changes in light intensity across the whole visual field — this fast response is accelerated even more by the large nerve bundles which rush the information to the brain. Focusing the image would also cause the sun's image to be focused on a few receptors. These could possibly be damaged by the intense light; shielding the receptors would block out some light and reduce their sensitivity.
This fast response has led to suggestions that the ocelli of insects are used mainly in flight, because they can be used to detect sudden changes in which way is up (because light, especially UV light which is absorbed by vegetation, usually comes from above).
Refractive cornea[change | change source]
The eyes of most land-living vertebrates (as well as those of some spiders, and insectlarvae) contain a fluid that has a higher refractive index than the air. That way, the lens does not have to reduce the focal length, because this is done by the fluid. That way, the lens can adjust the focus more easily. That way, a very high resolution can be obtained.
Reflector eyes[change | change source]
Instead of using a lens it is also possible to have cells inside the eye that act like mirrors. The image can then be reflected to focus at a central point. This design also means that someone looking into such an eye will see the same image as the organism which has them.
Many small organisms such as rotifers, copeopods and platyhelminthes use such this design, but their eyes are too small to produce usable images. Some larger organisms, such as scallops, also use reflector eyes. The scallop Pecten has up to 100 millimeter-scale reflector eyes fringing the edge of its shell. It detects moving objects as they pass successive lenses.
Compound eyes[change | change source]
Main article: Compound eye
Compound eyes are different from simple eyes. Instead of having one organ that can sense light, they put together many such organs. Some compound eyes have thousands of them. The resulting image is put together in the brain, based on the signals of the many eye units. Each such unit is called ommatidium, several are called ommatidia. The ommatidia are located on a convex surface, each of them points in a slighly different direction. Unlike simple eyes, compound eyes have a very large angle of view. They can detect fast movement, and sometimes the polarization of light.
Compound eyes are common in arthropods, annelids, and some bivalved molluscs
Evolution of the eye[change | change source]
The evolution of eyes started with simplest light-sensitive patches in unicellular organisms. These eye-spots do nothing but detect if the surroundings are light or dark. Most animals have a biochemical 'clock' inside. These simple eye-spots are used to adjust this daily clock, which is called circadian rhythm. Some snails, for example, see no image (picture) at all, but they sense light, which helps them stay out of bright sunlight.
More complex eyes have not lost this function. A special type of cells in the eye senses light for a different purpose than seeing. These cells are called ganglion cells. They are located in the retina. They send their information about light to the brain along a different path (the retinohypothalamic tract). This information adjusts (synchronizes) the animal's circadian rhythm to nature's light/dark cycle of 24 hours. The system also works for some blind people who cannot see light at all.
Eyes that are a little bit better are shaped like cups, which lets the animal know where the light is coming from.
More complex eyes give the full sense of vision, including color, motion, and texture. These eyes have a round shape that makes light raysfocus on the back part of the eye, called the retina.
Other[change | change source]
Good fliers like flies or honey bees, or prey-catching insects like praying mantis or dragonflies, have specialized zones of ommatidia organized into a fovea area which gives sharp vision. In this zone the eyes are flattened and the facets are larger. The flattening allows more ommatidia to receive light from a spot. This gives a higher resolution.
The body of Ophiocoma wendtii, a type of brittle star, is covered with ommatidia, turning its whole skin into a compound eye. The same is true of many chitons.
References[change | change source]
|Wikimedia Commons has media related to Eyes.|
- ↑ 1.001.011.021.031.041.051.061.071.081.091.101.184.108.40.206.15Land M.F. & Fernald R.D. 1992. "The evolution of eyes". Annual Review of Neuroscience15: 1–29. doi:10.1146/annurev.ne.15.030192.000245.
- ↑Lamb T.D; Collin S.P. & Pugh E.N. Jr. 2007. Evolution of the vertebrate eye: opsins, photoreceptors, retina and eye cup. Nature Reviews Neuroscience. 8 (12): 960–976. 
- ↑Frentiu, Francesca D. & Briscoe Adriana D. (2008), "A butterfly eye's view of birds", BioEssays, 30: 1151, doi:10.1002/bies.20828
- ↑Kozmik, Zbynek et al 2008, "Assembly of the cnidarian camera-type eye from vertebrate-like components"(PDF), Proceedings of the National Academy of Sciences, 105 (26): 8989–8993, doi:10.1073/pnas.0800388105, PMID 18577593
- ↑Fernald, Russell D. 2006, "Casting a genetic light on the evolution of eyes", Science, 313 (5795): 1914–1918, doi:10.1126/science.1127889, PMID 17008522
- ↑ 6.06.16.2Wilson M. 1978, "The functional organisation of locust ocelli", Journal of Comparative Physiology (4): 297–316
- ↑Völkel R.; Eisner M. & Weible K.J. (2003). "Miniaturized imaging systems" (PDF). Microelectronic Engineering67-68 (1): 461–472. doi:10.1016/S0167-9317(03)00102-3. http://www.suss-microoptics.com/downloads/Publications/Miniaturized_Imaging_Systems.pdf.
- ↑Ritchie, Alexander (1985). "Ainiktozoon loganense Scourfield, a protochordate? from the Silurian of Scotland". Alcheringa9: 137.
- ↑Autrum H. Introduction in Autrum H. Comparative physiology and evolution of vision in invertebrates. A: Invertebrate photoreceptors. Handbook of Sensory Physiology. VII/6A. New York: Springer-Verlag. pp. 4, 8–9. ISBN 3-540-08837-7
- ↑Halder G; Callaerts P. & Gehring W.J. 1995. New perspectives on eye evolution. Curr. Opin. Genet. Dev. 5 (5): 602–609. 
Kidney transplantation or renal transplantation is the organ transplant of a kidney into a patient with end-stage renal disease. Kidney transplantation is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantation depending on the source of the donor organ.
Living-donor renal transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient.
Exchanges and chains are a novel approach to expand the living donor pool. In February 2012, this novel approach to expand the living donor pool resulted in the largest chain in the world, involving 60 participants organized by the National Kidney Registry. In 2014 the record for the largest chain was broken again by a swap involving 70 participants.
One of the earliest mentions about the real possibility of a kidney transplant was by American medical researcher Simon Flexner, who declared in a reading of his paper on "Tendencies in Pathology" in the University of Chicago in 1907 that it would be possible in the then-future for diseased human organs substitution for healthy ones by surgery, including arteries, stomach, kidneys and heart.
In 1933 surgeon Yuriy Voroniy from Kherson in the Soviet Union attempted the first human kidney transplant, using a kidney removed six hours earlier from the deceased donor to be reimplanted into the thigh. He measured kidney function using a connection between the kidney and the skin. His first patient died two days later, as the graft was incompatible with the recipient's blood group and was rejected.
It was not until June 17, 1950, when a successful transplant could be performed on Ruth Tucker, a 44-year-old woman with polycystic kidney disease, by Dr. Richard Lawler at Little Company of Mary Hospital in Evergreen Park, Illinois. Although the donated kidney was rejected ten months later because no immunosuppressive therapy was available at the time—the development of effective antirejection drugs was years away—the intervening time gave Tucker's remaining kidney time to recover and she lived another five years.
The first kidney transplants between living patients were undertaken in 1952 at the Necker hospital in Paris by Jean Hamburger although the kidney failed after 3 weeks of good function  and later in 1954 in Boston. The Boston transplantation, performed on December 23, 1954, at Brigham Hospital was performed by Joseph Murray, J. Hartwell Harrison, John P. Merrill and others. The procedure was done between identical twins Ronald and Richard Herrick to eliminate any problems of an immune reaction. For this and later work, Dr. Murray received the Nobel Prize for Medicine in 1990. The recipient, Richard Herrick, died eight years after the transplantation.
In 1955, Charles Rob, William James "Jim" Dempster (St Marys and Hammersmith, London) carried out the first deceased donor transplant in United Kingdom, which was unsuccessful. In July 1959, "Fred" Peter Raper (Leeds) performed first successful (8 months) deceased donor transplant in the UK. A year later, in 1960, the first successful living kidney transplant in the UK occurred, when Michael Woodruff performed one between identical twins in Edinburgh.
Until the routine use of medications to prevent and treat acute rejection, introduced in 1964, deceased donor transplantation was not performed. The kidney was the easiest organ to transplant: Tissue typing was simple, the organ was relatively easy to remove and implant, live donors could be used without difficulty, and in the event of failure, kidney dialysis was available from the 1940s. Tissue typing was essential to the success; early attempts in the 1950s on sufferers from Bright's disease had been very unsuccessful.
The major barrier to organ transplantation between genetically non-identical patients lay in the recipient's immune system, which would treat a transplanted kidney as a "non-self" and immediately or chronically reject it. Thus, having medications to suppress the immune system was essential. However, suppressing an individual's immune system places that individual at greater risk of infection and cancer (particularly skin cancer and lymphoma), in addition to the side effects of the medications.
The basis for most immunosuppressive regimens is prednisolone, a corticosteroid. Prednisolone suppresses the immune system, but its long-term use at high doses causes a multitude of side effects, including glucose intolerance and diabetes, weight gain, osteoporosis, muscle weakness, hypercholesterolemia, and cataract formation. Prednisolone alone is usually inadequate to prevent rejection of a transplanted kidney. Thus other, non-steroid immunosuppressive agents are needed, which also allow lower doses of prednisolone.
The indication for kidney transplantation is end-stage renal disease (ESRD), regardless of the primary cause. This is defined as a glomerular filtration rate < 15 ml/min/1.73 m2. Common diseases leading to ESRD include malignant hypertension, infections, diabetes mellitus, and focal segmental glomerulosclerosis; genetic causes include polycystic kidney disease, a number of inborn errors of metabolism, and autoimmune conditions such as lupus.
Diabetes is the most common known cause of kidney transplantation, accounting for approximately 25% of those in the US. The majority of renal transplant recipients are on dialysis (peritoneal dialysis or hemodialysis) at the time of transplantation. However, individuals with chronic kidney disease who have a living donor available may undergo pre-emptive transplantation before dialysis is needed. If a patient is put on the waiting list for a deceased donor transplant early enough, they may also be transplanted pre-dialysis.
Contraindications and requirements
Contraindications include both cardiac and pulmonary insufficiency, as well as hepatic disease and some cancers. Concurrent tobacco use and morbid obesity are also among the indicators putting a patient at a higher risk for surgical complications.
Kidney transplant requirements vary from program to program and country to country. Many programs place limits on age (e.g. the person must be under a certain age to enter the waiting list) and require that one must be in good health (aside from the kidney disease). Significant cardiovascular disease, incurable terminal infectious diseases and cancer are often transplant exclusion criteria. In addition, candidates are typically screened to determine if they will be compliant with their medications, which is essential for survival of the transplant. People with mental illness and/or significant on-going substance abuse issues may be excluded.
HIV was at one point considered to be a complete contraindication to transplantation. There was fear that immunosuppressing someone with a depleted immune system would result in the progression of the disease. However, some research seem to suggest that immunosuppressive drugs and antiretrovirals may work synergistically to help both HIVviral loads/CD4 cell counts and prevent active rejection.
Sources of kidneys
Since medication to prevent rejection is so effective, donors do not need to be similar to their recipient. Most donated kidneys come from deceased donors; however, the utilisation of living donors in the United States is on the rise. In 2006, 47% of donated kidneys were from living donors. This varies by country: for example, only 3% of kidneys transplanted during 2006 in Spain came from living donors. In Spain all citizens are potential organ donors in the case of their death, unless they explicitly opt out during their lifetime.
Approximately one in three donations in the US, UK, and Israel is now from a live donor. Potential donors are carefully evaluated on medical and psychological grounds. This ensures that the donor is fit for surgery and has no disease which brings undue risk or likelihood of a poor outcome for either the donor or recipient. The psychological assessment is to ensure the donor gives informed consent and is not coerced. In countries where paying for organs is illegal, the authorities may also seek to ensure that a donation has not resulted from a financial transaction.
The relationship the donor has to the recipient has evolved over the years. In the 1950s, the first successful living donor transplants were between identical twins. In the 1960s–1970s, live donors were genetically related to the recipient. However, during the 1980s–1990s, the donor pool was expanded further to emotionally related individuals (spouses, friends). Now the elasticity of the donor relationship has been stretched to include acquaintances and even strangers ('altruistic donors'). In 2009, Minneapolis transplant recipient Chris Strouth received a kidney from a donor who connected with him on Twitter, which is believed to be the first such transplant arranged entirely through social networking.
The acceptance of altruistic donors has enabled chains of transplants to form. Kidney chains are initiated when an altruistic donor donates a kidney to a patient who has a willing but incompatible donor. This incompatible donor then 'pays it forward' and passes on the generosity to another recipient who also had a willing but incompatible donor. Michael Rees from the University of Toledo developed the concept of open-ended chains. This was a variation of a concept developed at Johns Hopkins University. On July 30, 2008, an altruistic donor kidney was shipped via commercial airline from Cornell to the University of California, Los Angeles, thus triggering a chain of transplants. The shipment of living donor kidneys, computer-matching software algorithms, and cooperation between transplant centers has enabled long-elaborate chains to be formed.
In carefully screened kidney donors, survival and the risk of end-stage renal disease appear to be similar to those in the general population. However, some more recent studies suggest that lifelong risk of chronic kidney disease is several-fold higher in kidney donors although the absolute risk is still very small. A 2017 article in the New England Journal of Medicine suggests that persons with only one kidney including those who have donated a kidney for transplantation should avoid high protein diet and limit their protein intake to less than one gram per kilogram body weight per day in order to reduce the long-term risk of chronic kidney disease. Women who have donated a kidney have a higher risk of gestational hypertension and preeclampsia than matched nondonors with similar indicators of baseline health. Traditionally, the donor procedure has been through a single incision of 4–7 inches (10–18 cm), but live donation is being increasingly performed by laparoscopic surgery. This reduces pain and accelerates recovery for the donor. Operative time and complications decreased significantly after a surgeon performed 150 cases. Live donor kidney grafts have higher long-term success rates than those from deceased donors. Since the increase in the use of laparoscopic surgery, the number of live donors has increased. Any advance which leads to a decrease in pain and scarring and swifter recovery has the potential to boost donor numbers. In January 2009, the first all-robotic kidney transplant was performed at Saint Barnabas Medical Center through a two-inch incision. In the following six months, the same team performed eight more robotic-assisted transplants.
In 2004 the FDA approved the Cedars-Sinai High Dose IVIG therapy which reduces the need for the living donor to be the same blood type (ABO compatible) or even a tissue match. The therapy reduced the incidence of the recipient's immune system rejecting the donated kidney in highly sensitized patients.
In 2009 at the Johns Hopkins Medical Center, a healthy kidney was removed through the donor's vagina. Vaginal donations promise to speed recovery and reduce scarring. The first donor was chosen as she had previously had a hysterectomy. The extraction was performed using natural orifice transluminal endoscopic surgery, where an endoscope is inserted through an orifice, then through an internal incision, so that there is no external scar. The recent advance of single port laparoscopy requiring only one entry point at the navel is another advance with potential for more frequent use.
Main article: Organ trade
In the developing world some people sell their organs illegally. Such people are often in grave poverty or are exploited by salespersons. The people who travel to make use of these kidneys are often known as 'transplant tourists'. This practice is opposed by a variety of human rights groups, including Organs Watch, a group established by medical anthropologists, which was instrumental in exposing illegal international organ selling rings. These patients may have increased complications owing to poor infection control and lower medical and surgical standards. One surgeon has said that organ trade could be legalised in the UK to prevent such tourism, but this is not seen by the National Kidney Research Fund as the answer to a deficit in donors.
In the illegal black market the donors may not get sufficient after-operation care, the price of a kidney may be above $160,000, middlemen take most of the money, the operation is more dangerous to both the donor and receiver, and the buyer often gets hepatitis or HIV. In legal markets of Iran the price of a kidney is $2,000 to $4,000.
An article by Gary Becker and Julio Elias on "Introducing Incentives in the market for Live and Cadaveric Organ Donations" said that a free market could help solve the problem of a scarcity in organ transplants. Their economic modeling was able to estimate the price tag for human kidneys ($15,000) and human livers ($32,000).
Jason Brennan and Peter Jaworski of the CATO Institute have also argued that any moral objections to a market for organs aren't inherent in the market, but rather, the activity itself.
Now monetary compensation for organ donors is being legalised in Australia and Singapore. Kidney disease organisations in both countries have expressed their support.
Deceased donors can be divided in two groups:
Although brain-dead (or 'heart beating') donors are considered dead, the donor's heart continues to pump and maintain the circulation. This makes it possible for surgeons to start operating while the organs are still being perfused (supplied blood). During the operation, the aorta will be cannulated, after which the donor's blood will be replaced by an ice-cold storage solution, such as UW (Viaspan), HTK, or Perfadex. Depending on which organs are transplanted, more than one solution may be used simultaneously. Due to the temperature of the solution, and since large amounts of cold NaCl-solution are poured over the organs for a rapid cooling, the heart will stop pumping.
'Donation after Cardiac Death' donors are patients who do not meet the brain-dead criteria but, due to the unlikely chance of recovery, have elected via a living will or through family to have support withdrawn. In this procedure, treatment is discontinued (mechanical ventilation is shut off). After a time of death has been pronounced, the patient is rushed to the operating room where the organs are recovered. Storage solution is flushed through the organs. Since the blood is no longer being circulated, coagulation must be prevented with large amounts of anti-coagulation agents such as heparin. Several ethical and procedural guidelines must be followed; most importantly, the organ recovery team should not participate in the patient's care in any manner until after death has been declared.
In general, the donor and recipient should be ABO blood group and crossmatch (human leukocyte antigen — HLA) compatible. If a potential living donor is incompatible with their recipient, the donor could be exchange for a compatible kidney. Kidney exchange, also known as "kidney paired donation" or "chains" have recently gained popularity.
In an effort to reduce the risk of rejection during incompatible transplantation, ABO-incompatible and densensitization protocols utilizing intravenous immunoglobulin (IVIG) have been developed, with the aim to reduce ABO and HLA antibodies that the recipient may have to the donor.
In the 1980s, experimental protocols were developed for ABO-incompatible transplants using increased immunosuppression and plasmapheresis. Through the 1990s these techniques were improved and an important study of long-term outcomes in Japan was published. Now, a number of programs around the world are routinely performing ABO-incompatible transplants.
The level of sensitization to donor HLA antigens is determined by performing a panel reactive antibody test on the potential recipient. In the United States, up to 17% of all deceased donor kidney transplants have no HLA mismatch. However, HLA matching is a relatively minor predictor of transplant outcomes. In fact, living non-related donors are now almost as common as living (genetically)-related donors.
In most cases the barely functioning existing kidneys are not removed, as removal has been shown to increase the rates of surgical morbidity. Therefore, the kidney is usually placed in a location different from the original kidney. Often this is in the iliac fossa so it is often necessary to use a different blood supply:
The donor ureter is anastomosed with the recipient bladder.
There is disagreement in surgical textbooks regarding which side of the recipient’s pelvis to use in receiving the transplant. Campbell's Urology (2002) recommends placing the donor kidney in the recipient’s contralateral side (i.e. a left sided kidney would be transplanted in the recipient's right side) to ensure the renal pelvis and ureter are anterior in the event that future surgeries are required. In an instance where there is doubt over whether there is enough space in the recipient’s pelvis for the donor's kidney, the textbook recommends using the right side because the right side has a wider choice of arteries and veins for reconstruction. Smith's Urology (2004) states that either side of the recipient's pelvis is acceptable; however the right vessels are 'more horizontal' with respect to each other and therefore easier to use in the anastomoses. It is unclear what is meant by the words 'more horizontal'. Glen's Urological Surgery (2004) recommends putting the kidney in the contralateral side in all circumstances. No reason is explicitly put forth; however, one can assume the rationale is similar to that of Campbell, i.e. to ensure that the renal pelvis and ureter are most anterior in the event that future surgical correction becomes necessary.
See also: Pancreas transplantation
Occasionally, the kidney is transplanted together with the pancreas. University of Minnesota surgeons Richard Lillehei and William Kelly perform the first successful simultaneous pancreas-kidney transplant in the world in 1966. This is done in patients with diabetes mellitus type 1, in whom the diabetes is due to destruction of the beta cells of the pancreas and in whom the diabetes has caused renal failure (diabetic nephropathy). This is almost always a deceased donor transplant. Only a few living donor (partial) pancreas transplants have been done. For individuals with diabetes and renal failure, the advantages of earlier transplant from a living donor (if available) are far superior to the risks of continued dialysis until a combined kidney and pancreas are available from a deceased donor. A patient can either receive a living kidney followed by a donor pancreas at a later date (PAK, or pancreas-after-kidney) or a combined kidney-pancreas from a donor (SKP, simultaneous kidney-pancreas).
Transplanting just the islet cells from the pancreas is still in the experimental stage, but shows promise. This involves taking a deceased donor pancreas, breaking it down, and extracting the islet cells that make insulin. The cells are then injected through a catheter into the recipient and they generally lodge in the liver. The recipient still needs to take immunosuppressants to avoid rejection, but no surgery is required. Most people need two or three such injections, and many are not completely insulin-free.
The transplant surgery takes about three hours. The donor kidney will be placed in the lower abdomen and its blood vessels connected to arteries and veins in the recipient's body. When this is complete, blood will be allowed to flow through the kidney again. The final step is connecting the ureter from the donor kidney to the bladder. In most cases, the kidney will soon start producing urine.
Depending on its quality, the new kidney usually begins functioning immediately. Living donor kidneys normally require 3–5 days to reach normal functioning levels, while cadaveric donations stretch that interval to 7–15 days. Hospital stay is typically for 4–10 days. If complications arise, additional medications (diuretics) may be administered to help the kidney produce urine.
Immunosuppressant drugs are used to suppress the immune system from rejecting the donor kidney. These medicines must be taken for the rest of the recipient's life. The most common medication regimen today is a mixture of tacrolimus, mycophenolate, and prednisolone. Some recipients may instead take ciclosporin, sirolimus, or azathioprine. The risk of early rejection of the transplanted kidney is increased if corticosteroids are avoided or withdrawn after the transplantation. Ciclosporin, considered a breakthrough immunosuppressive when first discovered in the 1980s, ironically causes nephrotoxicity and can result in iatrogenic damage to the newly transplanted kidney. Tacrolimus, which is a similar drug, also causes nephrotoxicity. Blood levels of both must be monitored closely and if the recipient seems to have declining renal function or proteinuria, a biopsy may be necessary to determine whether this is due to rejection  or ciclosporin or tacrolimus intoxication .
Post operatively, kidneys are periodically assessed by ultrasound to assess for the imaging and physiologic changes that accompany transplant rejection. Imaging also allows evaluation of supportive structures such as the anastomosed transplant artery, vein, and ureter, to ensure they are stable in appearance.
The major sonographic scale in quantitative ultrasound assessment is with a multipoint assessment of the resistive index (RI), beginning at the main renal artery and vein and ending at the arcuate vessels. It is calculated as follows:
- RI = (peak systolic velocity – end diastolic velocity ) / peak systolic velocity
The normal value is ≈ 0.60, with 0.70 being the upper limits of normal.
Kidney transplant recipients are discouraged from consuming grapefruit, pomegranate and green tea products. These food products are known to interact with the transplant medications, specifically tacrolimus, cyclosporin and sirolimus; the blood levels of these drugs may be increased, potentially leading to an overdose.
Acute rejection occurs in 10–25% of people after transplant during the first 60 days. Rejection does not necessarily mean loss of the organ, but it may necessitate additional treatment and medication adjustments.
Problems after a transplant may include: Post operative complication, bleeding, infection, vascular thrombosis and urinary complications
A patient's age and health condition before transplantation affect the risk of complications. Different transplant centers have different success at managing complications and therefore, complication rates are different from center to center.
The average lifetime for a donated kidney is ten to fifteen years. When a transplant fails, a patient may opt for a second transplant, and may have to return to dialysis for some intermediary time.
Infections due to the immunosuppressant drugs used in people with kidney transplants most commonly occur in mucocutaneous areas (41%), the urinary tract (17%) and the respiratory tract (14%). The most common infective agents are bacterial (46%), viral (41%), fungal (13%), and protozoan (1%). Of the viral illnesses, the most common agents are human cytomegalovirus (31.5%), herpes simplex (23.4%), and herpes zoster (23.4%). BK virus is now being increasingly recognised. Infection is the cause of death in about one third of people with renal transplants, and pneumonias account for 50% of the patient deaths from infection.
Postoperative bleeding following kidney transplant as seen on ultrasound
Postoperative bleeding following kidney transplant as seen on ultrasound
Postoperative bleeding following kidney transplant as seen on ultrasound
Postoperative bleeding following kidney transplant as seen on ultrasound
Kidney transplantation is a life-extending procedure. The typical patient will live 10 to 15 years longer with a kidney transplant than if kept on dialysis. The increase in longevity is greater for younger patients, but even 75-year-old recipients (the oldest group for which there is data) gain an average four more years of life. People generally have more energy, a less restricted diet, and fewer complications with a kidney transplant than if they stay on conventional dialysis.
Some studies seem to suggest that the longer a patient is on dialysis before the transplant, the less time the kidney will last. It is not clear why this occurs, but it underscores the need for rapid referral to a transplant program. Ideally, a kidney transplant should be pre-emptive, i.e., take place before the patient begins dialysis. The reason why kidneys fail over time after transplantation has been elucidated in recent years. Apart from recurrence of the original kidney disease, also rejection (mainly antibody-mediated rejection) and progressive scarring (multifactorial) play a decisive role. Avoiding rejection by strict medication adherence is of utmost importance to avoid failure of the kidney transplant.
At least four professional athletes have made a comeback to their sport after receiving a transplant: New Zealand rugby union player Jonah Lomu, German-Croatian Soccer Player Ivan Klasnić, and NBA basketballers Sean Elliott and Alonzo Mourning.
|Country||Year||Cadaveric donor||Living donor||Total transplants|
In addition to nationality, transplantation rates differ based on race, sex, and income. A study done with patients beginning long-term dialysis showed that the socio-demographic barriers to renal transplantation are relevant even before patients are on the transplant list. For example, different socio-demographic groups express different interest and complete pre-transplant workup at different rates. Previous efforts to create fair transplantation policies have focused on patients currently on the transplantation waiting list.
In the U.S. health system
Transplant recipients must take immunosuppressive anti-rejection drugs for as long as the transplanted kidney functions. The routine immunosuppressives are tacrolimus (Prograf), mycophenolate (Cellcept), and prednisolone; these drugs cost US$1,500 per month. In 1999 the United States Congress passed a law that restricts Medicare from paying for more than three years for these drugs, unless the patient is otherwise Medicare-eligible. Transplant programs may not transplant a patient unless the patient has a reasonable plan to pay for medication after the Medicare expires; however, patients are almost never turned down for financial reasons alone. Half of end-stage renal disease patients only have Medicare coverage.
In March 2009 a bill was introduced in the U.S. Senate, 565 and in the House, H.R. 1458 that will extend Medicare coverage of the drugs for as long as the patient has a functioning transplant. This means that patients who have lost their jobs and insurance will not also lose their kidney and be forced back on dialysis. Dialysis is currently using up $17 billion yearly of Medicare funds and total care of these patients amounts to over 10% of the entire Medicare budget.
The United Network for Organ Sharing, which oversees the organ transplants in the United States, allows transplant candidates to register at two or more transplant centers, a practice known as 'multiple listing'. The practice has been shown to be effective in mitigating the dramatic geographic disparity in the waiting time for organ transplants, particularly for patients residing in high-demand regions such as Boston. The practice of multiple-listing has also been endorsed by medical practitioners.
- Steven Cojocaru (born 1970), Canadian fashion critic, transplants in ???? and 2005
- Natalie Cole (1950–2015), American singer, transplant in 2009 (survival: 6 years)
- Gary Coleman (1968–2010), American actor, transplant dates unknown
- Lucy Davis (born 1973), English actress, transplant in 1997
- Kenny Easley (born 1959), American football player, transplant in 1990
- Aron Eisenberg (born 1969), American actor, transplant in 2015
- Sean Elliott (born 1968), American basketball player, transplant in 1999
- Selena Gomez (born 1992), American singer and actress, transplant in 2017
- Jennifer Harman (born 1964), American poker player, transplants in ???? and 2004
- Ken Howard (born 1932), English artist, transplant in 2000
- Ivan Klasnić (born 1980), Croatian footballer, transplant in 2007
- Jimmy Little (1937–2012), Australian musician and actor, transplant in 2004 (survival: 8 years)
- Jonah Lomu (1975–2015), New Zealand rugby player, transplant in 2004 (survival: 11 years)
- George Lopez (born 1961), American comedian and actor, transplant in 2005
- Alonzo Mourning (born 1970), American basketball player, transplant in 2003
- Kerry Packer (1937–2005), Australian businessman, transplant in 2000 (survival: 5 years)
- Charles Perkins (1936–2000), Australian footballer and activist, transplant in 1972 (survival: 28 years)
- Billy Preston (1946–2006), American musician, transplant in 2002 (survival: 4 years)
- Neil Simon (born 1927), American playwright, transplant in 2004
- Ron Springs (1956–2011), American football player, transplant in 2007 (survival: 4 years)
- Tomomi "Jumbo" Tsuruta (1951–2000), Japanese professional wrestler, transplant in 2000 (survival: 1 month)
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- El-Agroudy, Amgad E.; Sabry, Alaa A.; Wafa, Ehab W.; Neamatalla, Ahmed H.; Ismail, Amani M.; Mohsen, Tarek; Khalil, Abd Allah; Shokeir, Ahmed A.; Ghoneim, Mohamed A. (2007). "Long-term follow-up of living kidney donors: a longitudinal study". BJU International. 100 (6): 1351–1355. doi:10.1111/j.1464-410X.2007.07054.x. ISSN 1464-4096. PMID 17941927.
- Kerry Grens, "Living kidney donations favor some patient groups: study", 'Reuters', Apr 9, 2012. https://www.reuters.com/article/2012/04/10/health-kidney-donations-idUSL3E8FA0A720120410
- Gore John L, et al. (2012). "The Socioeconomic Status of Donors and Recipients of Living Unrelated Renal Transplants in the United States". The Journal of Urology. 187 (5): 1760–1765. doi:10.1016/j.juro.2011.12.112. PMID 22425125.
- ^Sack, Kevin (18 Feb 2012). "60 Lives, 30 Kidneys, All Linked". New York Times.
- ^Pitts, Byron (15 Apr 2015). "Changing Lives Through Donating Kidneys to Strangers". ABC News Nightline.
- ^MAY TRANSPLANT THE HUMAN HEART (.PDF), The New York Times, January 2, 1908
- ^Matevossian E, Kern H, Hüser N, Doll D, Snopok Y, Nährig J, Altomonte J, Sinicina I, Friess H, Thorban S (Dec 2009). "Surgeon Yurii Voronoy (1895–1961) – a pioneer in the history of clinical transplantation: in Memoriam at the 75th Anniversary of the First Human Kidney Transplantation". Transplant International. 22 (12): 1132–1139. doi:10.1111/j.1432-2277.2009.00986.x. PMID 19874569.
- ^Stressmarq.com; Indiatoday.intoday.in; Healthcentral.com (retrieved 12 February 2018)
- ^David Petechuk (2006). Organ transplantation. Greenwood Publishing Group. p. 11. ISBN 0-313-33542-7.
- ^Legendre, Ch; Kreis, H. (November 2010). "A Tribute to Jean Hamburger's Contribution to Organ Transplantation". American Journal of Transplantation. 10 (11): 2392–2395. doi:10.1111/j.1600-6143.2010.03295.x. PMID 20977631.