Joined: 05 Feb 2006
Location: Devon, UK
|Posted: Mon Feb 06, 2006 11:15 pm Post subject: Medical terminology
|Alpha 1-antitrypsin deficiency (A1AD or Alpha-1)
is a genetic disorder caused by reduced levels of alpha 1-antitrypsin in the blood. It can lead to emphysema and, in some cases, to liver disease.
Symptoms of alpha-1 antitrypsin deficiency include shortness of breath, recurring respiratory infections, or obstructive asthma that does not respond to treatment. Individuals with alpha-1 may develop emphysema during their thirties or forties, without a history of significant smoking (although smoking greatly increases the risk for emphysema). A1AD also causes impaired liver function in some patients and may lead to cirrhosis and liver failure (15%). It is the leading cause of liver transplantation in newborns.
Alpha 1-antitrypsin (AAT) is produced in the liver, and one of its functions is to protect the lungs from the neutrophil elastase enzyme. Normal blood levels of alpha-1 antitrypsin are 1.5-3.5 gm/l. In individuals with PiSS, PiMZ and PiSZ phenotypes, blood levels of AAT are reduced to between 40 and 60 % of normal levels. This is sufficient to protect the lungs from the effects of elastase in people who do not smoke. However, in individuals with the PiZZ phenotype, AAT levels are less than 15 % of normal, and patients are likely to develop emphysema at a young age; 50 % of these patients will develop liver cirrhosis, because the A1AT is not secreted properly and instead accumulates in the liver. A liver biopsy in such cases will reveal PAS-positive, diastase-negative granules.
Cigarette smoke is especially harmful to individuals with A1AD. In addition to increasing the inflammatory reaction in the airways, cigarette smoke directly inactivates alpha 1-antitrypsin by oxidizing essential methionine residues to sulfoxide forms, decreasing the enzyme activity by a rate of 2000.
People of northern European ancestry are at the highest risk for A1AD. Four percent carry the PiZ allele; between 1 in 625 and 1 in 2000 are homozygous.
alpha-1-protease (AAT / A1AT):
A substance in blood transported to the lungs that inhibits the digestive activity of trypsin and other proteases which digest proteins (Elastin). Deficiency of this substance is associated with emphysema.
Are the very small air sacs that are the destination of air breathed in. The CAPILLARIES are blood vessels that are imbedded in the walls of the alveoli. Blood passes through the capillaries, brought to them by the PULMONARY ARTERY and taken away by the PULMONARY VEIN. While in the capillaries the blood gives off carbon dioxide through the capillary wall into the alveoli and takes up oxygen from the air in the alveoli.
Autosomal Recessive Inheritance:
An abnormal gene on one of the autosomal chromosomes (one of the first 22 "non-sex" chromosomes) from each parent is required to cause the disease. People with only one abnormal gene in the gene pair are called carriers, but since the gene is recessive they do not exhibit the disease. The inheritance of genetic diseases, abnormalities, or traits is described by both the type of chromosome on which the abnormal gene resides (autosomal or sex chromosome), and by whether the gene itself is dominant or recessive. This is due to whether a single defective gene from one parent (dominant inheritance) or both copies of the gene (one from each parent) are defective (recessive inheritance).
Bovine pericardium buttress (Peri-Strips):
Peri-Strips Dry® Staple Line Reinforcement for thoracic surgery controls bleeding and leaks at the staple line.
Peri-Strips Dry is comprised of two vacuum-dried strips of biological tissue derived from bovine pericardium and manufactured with Synovis Surgical Innovations' exclusive Apex Processing®
- Proven to provide a statistically significant reduction in leaks and bleeding
- Exceptionally low adverse event rate: less than 0.01%
- Exhibits good host tissue incorporation and does not promote calcification
- Demonstrated to reduce hospital stays
Bovine collagen (INSTAT):
less expensive but equally effective buttress for staple lines.
Are the smallest subdivisions of the bronchial tubes, at the end of which are the air sacs or alveoli (plural of alveolus).
are areas of out-pouching of the end of the breathing tubes. Thin-walled sacs greater than 10 millimeters in diameter.
COPD (Chronic Obstructive Pulmonary Disease):
is a general term which includes the conditions chronic bronchitis and emphysema. Smoking is the cause in the vast majority of cases.
is an inflammation of the connective tissue between the breastbone and the ribs. It causes pain in the chest that can be reproduced by pressing on the affected area between the ribs. This pain can be quite exquisite, especially after rigorous exercise. While it can be extremely painful, it is considered to be a benign condition that generally resolves in 6-8 weeks. Treatment options are quite limited and usually only involve rest and pain relievers but in a very small number of cases cortisone injections and even surgery are sometimes necessary.
This procedure removes a restrictive, fibrous membrane or layer of tissue from the pleural surface of the lung. It may also be removed from the diaphragm or chest wall. This procedure is used in the treatment of chronic pleural infections or empyemas. The purpose of the procedure is to free the encased or “trapped lung” allowing the expansion of the lung to become easier.
Ehlers-Danlos Syndrome (EDS):
Is the name given to a group of heritable connective tissue disorders. EDS can affect the skin, ligaments, and internal organs.
is an enzyme from the class of proteases (or better peptidases) that break down proteins. Elastase breaks down elastin, an elastic fibre that together with collagen determines the mechanical properties of connective tissue. Elastase is inhibited by the acute phase protein alpha-1-antitryspin (A1AT), which binds covalently 1:1 to elastase. alpha-1-antitryspin deficiency (A1AD) leads to uninhibited destruction of elastic fibre by elastase; the main result is pulmonary emphysema.
is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. It is primarily composed of the amino acids glycine, valine, alanine and proline. Elastin is made by linking many soluble tropoelastin protein molecules to make a massive insoluble, durable cross-linked array. Elastin is particularly abundant in large elastic blood vessels such as the aorta.
is damage to the smaller airways and airsacs (alveoli) of the lungs.
Fibrin tissue glue is a biological product that can stimulate wound healing. The three primary uses of fibrin sealant are: controlling bleeding (hemostatic agent), sealing tissue planes, and delivering drugs, such as antibiotics, growth factors, or even chemotherapeutic agents. Use of surgical glues or adhesives in the 20th Century is a relatively recent phenomenon, considering the fact that surgeons have been cutting and sewing tissues as far back as 3500 B.C. Fibrin sealant has proved to be one the most important of these "new" surgical tissue adhesives.
is the result of disorderly smooth muscle proliferation throughout the bronchioles, alveolar septa, perivascular spaces, and lymphatics, resulting in the obstruction of small airways (leading to pulmonary cyst formation and pneumothorax) and lymphatics (leading to chylous pleural effusion). LAM occurs in a sporadic form, which only affects females, who are usually of childbearing age. LAM also occurs in patients who have tuberous sclerosis. The cause of the sporadic form of LAM is unknown. This type only affects women.
Lung resections remove damaged/diseased tissue. Depending on the type, size and location, several surgical interventions may be considered. Wedge resection/segmentectomy, where a segment or small portion of a lung lobe is removed. Lobectomy, where a lobe of the lung is removed. There are three lobes on the right and two on the left. Pneumonectomy, where the entire lung on one side is removed.
Marfan Syndrome (MFS):
is a variable disorder of the connective tissue that affects many organ systems including the skeleton, eyes, heart, lungs and blood vessels.
Non-steroidal anti-inflammatory drugs:
usually abbreviated to NSAIDs, are drugs with analgesic, antipyretic and anti-inflammatory effects - they reduce pain, fever and inflammation. The term "non-steroidal" is used to distinguish these drugs from steroids, which (amongst a broad range of other effects) have a similar eicosanoid-depressing, anti-inflammatory action. NSAIDs are sometimes also referred to as non-steroidal anti-inflammatory agents/analgesics (NSAIAs). The most prominent members of this group of drugs are aspirin and ibuprofen. Paracetamol (acetaminophen) has negligible anti-inflammatory activity, and is strictly speaking not an NSAID.
Beginning in 1829, with the isolation of salicylic acid from the folk remedy willow bark, NSAIDs have become an important part of the pharmaceutical treatment of pain (at low doses) and inflammation (at higher doses). Part of the popularity of NSAIDs is that, unlike opioids, they do not produce sedation, respiratory depression, or addiction. NSAIDs, however, are not without their own problems (see below). Certain NSAIDs, including ibuprofen and aspirin, have become accepted as relatively safe and are available over-the-counter without prescription.
Most NSAIDs act as non-selective inhibitors of the enzyme cyclooxygenase, inhibiting both the cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) isoenzymes. Cyclooxygenase catalyses the formation of prostaglandins and thromboxane from arachidonic acid (itself derived from the cellular phospholipid bilayer by phospholipase A2). Prostaglandins act (among other things) as messenger molecules in the process of inflammation.
is any agent that binds to opioid receptors, found principally in the central nervous system and gastrointestinal tract. There are four broad classes of opioids: endogenous opioid peptides, produced in the body; opium alkaloids, such as morphine (the prototypical opioid) and codeine; semi-synthetic opioids such as heroin and oxycodone; and fully synthetic opioids such as pethidine and methadone that have structures unrelated to the opium alkaloids.
Are the two membranes, actually one continuous one folded on itself, that surround each lobe of the lungs and separate the lungs from the chest wall. there is a visceral pleura that is firmly attached to the lung tissue itself, and a parietal pleura that is attached to the thoracic body wall. Between these membranes, there is a tiny, almost non-existent space, called the pleural cavity. Since the visceral and parieta pleurae are serous membranes, they secrete serous fluid. Therefore, serous fluid lies in the pleural cavity.
When the thorax expands, that pulls on the parietal pleura (since the parietal pleura is attached to the thoracic body wall). You might think that this would cause the two pleural membranes to pull apart, but that doesn't happen. Instead, the serous fluid has enough surface tension to act like a glue and hold the visceral pleura to the parietal pleura. This way, as the parietal pleura is drawn out by the thoracic body wall, the visceral pleura moves with it. As the visceral pleura expands, since it is stuck to the lung tissue, the lung is forced to expand. This is how the pleurae lead to expansion of the lungs themselves.
Selective COX inhibitors:
The discovery of COX-2 in 1991 by Daniel L. Simmons at Brigham Young University raised the hope of developing an effective NSAID without the gastric problems characteristic of these agents. It was thought that selective inhibition of COX-2 would result in anti-inflammatory action without disrupting gastroprotective prostaglandins.
COX-1 is a constitutively expressed enzyme with a "house-keeping" role in regulating many normal physiological processes. One of these is in the stomach lining, where prostaglandins serve a protective role, preventing the stomach mucosa from being eroded by its own acid. When non-selective COX-1/COX-2 inhibitors (such as aspirin, ibuprofen, and naproxen)) lower stomach prostaglandin levels, these protective effects are lost and ulcers of the stomach or duodenum and potentially internal bleeding can result. COX-2 is an enzyme facultatively expressed in inflammation, and it is inhibition of COX-2 that produces the desirable effects of NSAIDs.
The relatively selective COX-2 inhibiting oxicam, meloxicam, was the first step towards developing a true COX-2 selective inhibitor. Coxibs, the newest class of NSAIDs, can be considered as true COX-2 selective inhibitors, and include celecoxib, rofecoxib, valdecoxib, parecoxib and etoricoxib.
Controversies with COX-2 inhibitors
While it was hoped that this COX-2 selectivity would reduce gastrointestinal adverse drug reactions (ADRs), there is little conclusive evidence that this is true. The original study touted by Searle (now part of Pfizer), showing a reduced rate of ADRs for celecoxib, was later revealed to be based on preliminary data - the final data showed no significant difference in ADRs when compared with diclofenac.
Rofecoxib however, which has since been withdrawn, had been shown to produce significantly fewer gastrointestinal ADRs compared to naproxen. (Bombardier et al, 2000). This study, the VIGOR trial, raised the issue of the cardiovascular safety of the coxibs - a statistically insignificant increase in the incidence of myocardial infarctions was observed in patients on rofecoxib. Further data, from the APPROVe trial, showed a relative risk of cardiovascular events of 1.97 versus placebo - a result which resulted in the worldwide withdrawal of rofecoxib in October 2004.
Simmons also co-discovered COX-3 in 2002 and analyzed this new isozyme's relation to acetaminophen, arguably the most widely used analgesic drug in the world. (Chandrasekharan et al, 2002). The authors postulated that inhibition of COX-3 could represent a primary central mechanism by which these drugs decrease pain and possibly fever.
The clinical ramifications and knowledge of COX isozymes are rapidly expanding and may offer significant hope for future treatments of pain, inflammation, and fever.
A spirometer is a device which measures the amount of air that you can blow out.
The surgical incision made through the breastbone (sternum). When the operation is completed the breastbone (sternum) is wired together and allowed to heal, (like you would expect a broken bone to heal). The wires remain in place unless they cause a problem for an individual patient and then they can be removed.
Talc (used in pleurodesis):
A soft white powder, consisting of magnesium silicate, used in dusting powders and skin applications.
Tetracycline (used in chemical pleurodesis):
Tetracycline, a "broad-spectrum" antibiotic, is used to treat bacterial infections such as Rocky Mountain spotted fever, typhus fever, and tick fevers; upper respiratory infections; pneumonia; gonorrhea; amoebic infections; and urinary tract infections. Tetracycline is recommended as the first line sclerosant therapy in both primary and secondary pneumothoraces.
A thin scope inserted through an incision into the chest.
A Valsalva maneuver is any attempted exhalation against a closed glottis or against a closed mouth and nose. It is also known as Valsalva's test and Valsalva's method, after Antonio Maria Valsalva, a famous Italian anatomist. Valsalva's initial intention for the maneuver was as a method of expressing pus from the middle ear.
A Valsalva maneuver performed against a closed glottis results in a drastic increase in pressure in the thoracic cavity, the airtight section of the torso that houses the lungs and heart. In normal exhalation, the diaphragm contracts, pushing up and into the thoracic cavity. This increases pressure in the cavity and forces the air out of the lungs. However, when the air cannot escape, as when the glottis is closed in a Valsalva maneuver, pressure simply continues to build inside the thoracic cavity until the diaphragm relaxes or the air is allowed to escape. This reduces the amount of blood flow into the thoracic cavity, especially in the veins leading to the right atrium of the heart.
A shoulder injury or condition in which the scapula or shoulder blade sticks out at the back, particular when pushing against something such as a wall.
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