Pulmonary emphysema is a chronic respiratory disease characterized by abnormal, permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of their walls and without obvious fibrosis. This results in loss of elastic recoil, which leads to trappling of air within the lungs and difficulty exhaling. It is often caused by cigarette smoking or long-term exposure to harmful pollutants. The disease is part of a group of conditions known as chronic obstructive pulmonary disease (COPD), which also includes chronic bronchitis.

Emphysema is a chronic respiratory disease characterized by abnormal, permanent enlargement of the airspaces called alveoli in the lungs, accompanied by destruction of their walls. This results in loss of elasticity and decreased gas exchange efficiency, causing shortness of breath and coughing. It is often caused by smoking or exposure to harmful pollutants. The damage to the lungs is irreversible, but quitting smoking and using medications can help alleviate symptoms and slow disease progression.

Pancreatic elastase is a type of elastase that is specifically produced by the pancreas. It is an enzyme that helps in digesting proteins found in the food we eat. Pancreatic elastase breaks down elastin, a protein that provides elasticity to tissues and organs in the body.

In clinical practice, pancreatic elastase is often measured in stool samples as a diagnostic tool to assess exocrine pancreatic function. Low levels of pancreatic elastase in stool may indicate malabsorption or exocrine pancreatic insufficiency, which can be caused by various conditions such as chronic pancreatitis, cystic fibrosis, or pancreatic cancer.

Alpha 1-Antitrypsin (AAT) deficiency is a genetic disorder that results from insufficient levels of the protective protein AAT in the blood and lungs. This protein is produced by the liver and helps to protect the lungs from damage caused by inflammation and the action of enzymes, such as neutrophil elastase, that are released during the immune response.

In people with AAT deficiency, the lack of adequate AAT levels leads to an uncontrolled increase in neutrophil elastase activity, which can cause damage to lung tissue and result in emphysema, a condition characterized by shortness of breath, coughing, and wheezing. Additionally, some individuals with AAT deficiency may develop liver disease due to the accumulation of abnormal AAT proteins in liver cells.

There are different variants or genotypes associated with AAT deficiency, with the most common and severe form being the PiZZ genotype. This variant is caused by mutations in the SERPINA1 gene, which encodes for the AAT protein. Individuals who inherit two copies of this mutated gene (one from each parent) will have very low levels of AAT in their blood and are at increased risk of developing emphysema and liver disease.

Diagnosis of AAT deficiency typically involves measuring AAT levels in the blood and performing genetic testing to identify specific variants of the SERPINA1 gene. Treatment may include lifestyle modifications, such as smoking cessation, bronchodilators, and corticosteroids to manage lung symptoms, as well as augmentation therapy with intravenous infusions of AAT protein to help slow disease progression in individuals with severe deficiency. Liver transplantation may be considered for those with advanced liver disease.

Subcutaneous emphysema is a medical condition where air or gas collects in the subcutaneous tissue, which lies beneath the skin and above the muscle layer. This tissue covers the entire body, but the collection of air usually occurs in the chest wall, neck, or face. The accumulation of air can cause swelling, crepitus (a crackling or crunching sound when touched), and tightness in the affected area. Subcutaneous emphysema is often associated with underlying conditions such as trauma, pulmonary disease, or certain medical procedures that result in air leaks from the lungs or other structures into the subcutaneous tissue. It can be a serious condition if left untreated, as it may lead to complications like mediastinal emphysema or tension pneumothorax. Immediate medical attention is necessary for proper diagnosis and treatment.

Alpha 1-antitrypsin (AAT, or α1-antiproteinase, A1AP) is a protein that is primarily produced by the liver and released into the bloodstream. It belongs to a group of proteins called serine protease inhibitors, which help regulate inflammation and protect tissues from damage caused by enzymes involved in the immune response.

Alpha 1-antitrypsin is particularly important for protecting the lungs from damage caused by neutrophil elastase, an enzyme released by white blood cells called neutrophils during inflammation. In the lungs, AAT binds to and inhibits neutrophil elastase, preventing it from degrading the extracellular matrix and damaging lung tissue.

Deficiency in alpha 1-antitrypsin can lead to chronic obstructive pulmonary disease (COPD) and liver disease. The most common cause of AAT deficiency is a genetic mutation that results in abnormal folding and accumulation of the protein within liver cells, leading to reduced levels of functional AAT in the bloodstream. This condition is called alpha 1-antitrypsin deficiency (AATD) and can be inherited in an autosomal codominant manner. Individuals with severe AATD may require augmentation therapy with intravenous infusions of purified human AAT to help prevent lung damage.

A lung is a pair of spongy, elastic organs in the chest that work together to enable breathing. They are responsible for taking in oxygen and expelling carbon dioxide through the process of respiration. The left lung has two lobes, while the right lung has three lobes. The lungs are protected by the ribcage and are covered by a double-layered membrane called the pleura. The trachea divides into two bronchi, which further divide into smaller bronchioles, leading to millions of tiny air sacs called alveoli, where the exchange of gases occurs.

Matrix metalloproteinase 12 (MMP-12) is a type of enzyme that belongs to the matrix metalloproteinase (MMP) family. MMPs are involved in the breakdown and remodeling of extracellular matrices, which are the structures that provide support and organization to cells in tissues and organs.

MMP-12 is also known as macrophage elastase because it is primarily produced by macrophages, a type of white blood cell that plays a key role in the immune system. MMP-12 is capable of degrading various components of the extracellular matrix, including elastin, a protein that provides elasticity to tissues such as lungs, arteries, and skin.

MMP-12 has been implicated in several physiological and pathological processes, including tissue remodeling, wound healing, inflammation, and cancer. Dysregulation of MMP-12 activity has been associated with various diseases, such as chronic obstructive pulmonary disease (COPD), atherosclerosis, and tumor metastasis.

Pulmonary alveoli, also known as air sacs, are tiny clusters of air-filled pouches located at the end of the bronchioles in the lungs. They play a crucial role in the process of gas exchange during respiration. The thin walls of the alveoli, called alveolar membranes, allow oxygen from inhaled air to pass into the bloodstream and carbon dioxide from the bloodstream to pass into the alveoli to be exhaled out of the body. This vital function enables the lungs to supply oxygen-rich blood to the rest of the body and remove waste products like carbon dioxide.

Mediastinal emphysema is a medical condition characterized by the presence of air or gas within the mediastinum, which is the central compartment of the thorax that contains the heart, esophagus, trachea, bronchi, thymus gland, and other associated structures.

In mediastinal emphysema, the air accumulates in the mediastinal tissues and spaces, leading to their abnormal distention or swelling. This condition can result from various causes, including:

* Pulmonary trauma or barotrauma (e.g., mechanical ventilation, scuba diving)
* Infections that cause gas-forming organisms (e.g., pneumomediastinum)
* Air leakage from the lungs or airways (e.g., bronchial rupture, esophageal perforation)
* Certain medical procedures (e.g., mediastinoscopy, tracheostomy)

Mediastinal emphysema can cause symptoms such as chest pain, cough, difficulty breathing, and swallowing problems. In severe cases, it may lead to life-threatening complications, including tension pneumothorax or mediastinitis. Treatment depends on the underlying cause and severity of the condition.

Respiratory Function Tests (RFTs) are a group of medical tests that measure how well your lungs take in and exhale air, and how well they transfer oxygen and carbon dioxide into and out of your blood. They can help diagnose certain lung disorders, measure the severity of lung disease, and monitor response to treatment.

RFTs include several types of tests, such as:

1. Spirometry: This test measures how much air you can exhale and how quickly you can do it. It's often used to diagnose and monitor conditions like asthma, chronic obstructive pulmonary disease (COPD), and other lung diseases.
2. Lung volume testing: This test measures the total amount of air in your lungs. It can help diagnose restrictive lung diseases, such as pulmonary fibrosis or sarcoidosis.
3. Diffusion capacity testing: This test measures how well oxygen moves from your lungs into your bloodstream. It's often used to diagnose and monitor conditions like pulmonary fibrosis, interstitial lung disease, and other lung diseases that affect the ability of the lungs to transfer oxygen to the blood.
4. Bronchoprovocation testing: This test involves inhaling a substance that can cause your airways to narrow, such as methacholine or histamine. It's often used to diagnose and monitor asthma.
5. Exercise stress testing: This test measures how well your lungs and heart work together during exercise. It's often used to diagnose lung or heart disease.

Overall, Respiratory Function Tests are an important tool for diagnosing and managing a wide range of lung conditions.

'Smoke' is not typically defined in a medical context, but it can be described as a mixture of small particles and gases that are released when something burns. Smoke can be composed of various components including carbon monoxide, particulate matter, volatile organic compounds (VOCs), benzene, toluene, styrene, and polycyclic aromatic hydrocarbons (PAHs). Exposure to smoke can cause a range of health problems, including respiratory symptoms, cardiovascular disease, and cancer.

In the medical field, exposure to smoke is often referred to as "secondhand smoke" or "passive smoking" when someone breathes in smoke from another person's cigarette, cigar, or pipe. This type of exposure can be just as harmful as smoking itself and has been linked to a range of health problems, including respiratory infections, asthma, lung cancer, and heart disease.

Helium is not a medical term, but it's a chemical element with symbol He and atomic number 2. It's a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gases section of the periodic table. In medicine, helium is sometimes used in medical settings for its unique properties, such as being less dense than air, which can help improve the delivery of oxygen to patients with respiratory conditions. For example, heliox, a mixture of helium and oxygen, may be used to reduce the work of breathing in patients with conditions like chronic obstructive pulmonary disease (COPD) or asthma. Additionally, helium is also used in cryogenic medical equipment and in magnetic resonance imaging (MRI) machines to cool the superconducting magnets.

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by the persistent obstruction of airflow in and out of the lungs. This obstruction is usually caused by two primary conditions: chronic bronchitis and emphysema. Chronic bronchitis involves inflammation and narrowing of the airways, leading to excessive mucus production and coughing. Emphysema is a condition where the alveoli (air sacs) in the lungs are damaged, resulting in decreased gas exchange and shortness of breath.

The main symptoms of COPD include progressive shortness of breath, chronic cough, chest tightness, wheezing, and excessive mucus production. The disease is often associated with exposure to harmful particles or gases, such as cigarette smoke, air pollution, or occupational dusts and chemicals. While there is no cure for COPD, treatments can help alleviate symptoms, improve quality of life, and slow the progression of the disease. These treatments may include bronchodilators, corticosteroids, combination inhalers, pulmonary rehabilitation, and, in severe cases, oxygen therapy or lung transplantation.

A pneumonectomy is a surgical procedure in which an entire lung is removed. This type of surgery is typically performed as a treatment for certain types of lung cancer, although it may also be used to treat other conditions such as severe damage or infection in the lung that does not respond to other treatments. The surgery requires general anesthesia and can be quite complex, with potential risks including bleeding, infection, pneumonia, and air leaks. Recovery from a pneumonectomy can take several weeks, and patients may require ongoing rehabilitation to regain strength and mobility.

Leukocytoclastic vasculitis, cutaneous is a type of vasculitis that is limited to the skin. Vasculitis refers to inflammation of the blood vessels, which can cause damage to the vessel walls and impair blood flow to various tissues in the body. In leukocytoclastic vasculitis, the small blood vessels (capillaries and venules) in the skin become inflamed, leading to damage and destruction of the vessel walls.

The term "leukocytoclastic" refers to the presence of nuclear debris from white blood cells (leukocytes) that have been destroyed within the affected blood vessels. This type of vasculitis is often associated with the deposition of immune complexes (formed by the interaction between antibodies and antigens) in the walls of the blood vessels, which triggers an inflammatory response.

Cutaneous leukocytoclastic vasculitis typically presents as palpable purpura (small to large, raised, purple or red spots on the skin), usually located on the lower extremities, but can also affect other areas of the body. Other symptoms may include burning or itching sensations in the affected area, and in some cases, ulcers or necrosis (tissue death) may occur.

The diagnosis of cutaneous leukocytoclastic vasculitis is typically made based on clinical presentation, laboratory tests, and histopathological examination of a skin biopsy specimen. Treatment usually involves addressing any underlying causes or triggers, as well as managing symptoms with medications such as corticosteroids or immunosuppressive agents.

Elastin is a protein that provides elasticity to tissues and organs, allowing them to resume their shape after stretching or contracting. It is a major component of the extracellular matrix in many tissues, including the skin, lungs, blood vessels, and ligaments. Elastin fibers can stretch up to 1.5 times their original length and then return to their original shape due to the unique properties of this protein. The elastin molecule is made up of cross-linked chains of the protein tropoelastin, which are produced by cells called fibroblasts and then assembled into larger elastin fibers by enzymes called lysyl oxidases. Elastin has a very long half-life, with some estimates suggesting that it can remain in the body for up to 70 years or more.

Panniculitis is a medical term that refers to inflammation of the subcutaneous fat, or the layer of fat located just beneath the skin. This condition can affect people of all ages and genders, although it is more commonly seen in middle-aged women. The inflammation can be caused by a variety of factors, including infections, autoimmune disorders, trauma, and medications.

The symptoms of panniculitis may include:

* Red, painful lumps or nodules under the skin
* Skin lesions that may be tender, warm, or bruised
* Swelling and redness in the affected area
* Fever, fatigue, and malaise (a general feeling of illness)

The diagnosis of panniculitis typically involves a physical examination, medical history, and sometimes a biopsy of the affected tissue. Treatment depends on the underlying cause of the inflammation and may include antibiotics, anti-inflammatory medications, or other therapies. In severe cases, hospitalization may be necessary to manage symptoms and prevent complications.

Smoking is not a medical condition, but it's a significant health risk behavior. Here is the definition from a public health perspective:

Smoking is the act of inhaling and exhaling the smoke of burning tobacco that is commonly consumed through cigarettes, pipes, and cigars. The smoke contains over 7,000 chemicals, including nicotine, tar, carbon monoxide, and numerous toxic and carcinogenic substances. These toxins contribute to a wide range of diseases and health conditions, such as lung cancer, heart disease, stroke, chronic obstructive pulmonary disease (COPD), and various other cancers, as well as adverse reproductive outcomes and negative impacts on the developing fetus during pregnancy. Smoking is highly addictive due to the nicotine content, which makes quitting smoking a significant challenge for many individuals.

X-ray computed tomography (CT or CAT scan) is a medical imaging method that uses computer-processed combinations of many X-ray images taken from different angles to produce cross-sectional (tomographic) images (virtual "slices") of the body. These cross-sectional images can then be used to display detailed internal views of organs, bones, and soft tissues in the body.

The term "computed tomography" is used instead of "CT scan" or "CAT scan" because the machines take a series of X-ray measurements from different angles around the body and then use a computer to process these data to create detailed images of internal structures within the body.

CT scanning is a noninvasive, painless medical test that helps physicians diagnose and treat medical conditions. CT imaging provides detailed information about many types of tissue including lung, bone, soft tissue and blood vessels. CT examinations can be performed on every part of the body for a variety of reasons including diagnosis, surgical planning, and monitoring of therapeutic responses.

In computed tomography (CT), an X-ray source and detector rotate around the patient, measuring the X-ray attenuation at many different angles. A computer uses this data to construct a cross-sectional image by the process of reconstruction. This technique is called "tomography". The term "computed" refers to the use of a computer to reconstruct the images.

CT has become an important tool in medical imaging and diagnosis, allowing radiologists and other physicians to view detailed internal images of the body. It can help identify many different medical conditions including cancer, heart disease, lung nodules, liver tumors, and internal injuries from trauma. CT is also commonly used for guiding biopsies and other minimally invasive procedures.

In summary, X-ray computed tomography (CT or CAT scan) is a medical imaging technique that uses computer-processed combinations of many X-ray images taken from different angles to produce cross-sectional images of the body. It provides detailed internal views of organs, bones, and soft tissues in the body, allowing physicians to diagnose and treat medical conditions.

Bronchoalveolar lavage (BAL) fluid is a type of clinical specimen obtained through a procedure called bronchoalveolar lavage. This procedure involves inserting a bronchoscope into the lungs and instilling a small amount of saline solution into a specific area of the lung, then gently aspirating the fluid back out. The fluid that is recovered is called bronchoalveolar lavage fluid.

BAL fluid contains cells and other substances that are present in the lower respiratory tract, including the alveoli (the tiny air sacs where gas exchange occurs). By analyzing BAL fluid, doctors can diagnose various lung conditions, such as pneumonia, interstitial lung disease, and lung cancer. They can also monitor the effectiveness of treatments for these conditions by comparing the composition of BAL fluid before and after treatment.

BAL fluid is typically analyzed for its cellular content, including the number and type of white blood cells present, as well as for the presence of bacteria, viruses, or other microorganisms. The fluid may also be tested for various proteins, enzymes, and other biomarkers that can provide additional information about lung health and disease.

Forced Expiratory Volume (FEV) is a medical term used to describe the volume of air that can be forcefully exhaled from the lungs in one second. It is often measured during pulmonary function testing to assess lung function and diagnose conditions such as chronic obstructive pulmonary disease (COPD) or asthma.

FEV is typically expressed as a percentage of the Forced Vital Capacity (FVC), which is the total volume of air that can be exhaled from the lungs after taking a deep breath in. The ratio of FEV to FVC is used to determine whether there is obstruction in the airways, with a lower ratio indicating more severe obstruction.

There are different types of FEV measurements, including FEV1 (the volume of air exhaled in one second), FEV25-75 (the average volume of air exhaled during the middle 50% of the FVC maneuver), and FEV0.5 (the volume of air exhaled in half a second). These measurements can provide additional information about lung function and help guide treatment decisions.

Pulmonary fibrosis is a specific type of lung disease that results from the thickening and scarring of the lung tissues, particularly those in the alveoli (air sacs) and interstitium (the space around the air sacs). This scarring makes it harder for the lungs to properly expand and transfer oxygen into the bloodstream, leading to symptoms such as shortness of breath, coughing, fatigue, and eventually respiratory failure. The exact cause of pulmonary fibrosis can vary, with some cases being idiopathic (without a known cause) or related to environmental factors, medications, medical conditions, or genetic predisposition.

Lung compliance is a measure of the ease with which the lungs expand and is defined as the change in lung volume for a given change in transpulmonary pressure. It is often expressed in units of liters per centimeter of water (L/cm H2O). A higher compliance indicates that the lungs are more easily distensible, while a lower compliance suggests that the lungs are stiffer and require more force to expand. Lung compliance can be affected by various conditions such as pulmonary fibrosis, pneumonia, acute respiratory distress syndrome (ARDS), and chronic obstructive pulmonary disease (COPD).

Pneumonia is an infection or inflammation of the alveoli (tiny air sacs) in one or both lungs. It's often caused by bacteria, viruses, or fungi. Accumulated pus and fluid in these air sacs make it difficult to breathe, which can lead to coughing, chest pain, fever, and difficulty breathing. The severity of symptoms can vary from mild to life-threatening, depending on the underlying cause, the patient's overall health, and age. Pneumonia is typically diagnosed through a combination of physical examination, medical history, and diagnostic tests such as chest X-rays or blood tests. Treatment usually involves antibiotics for bacterial pneumonia, antivirals for viral pneumonia, and supportive care like oxygen therapy, hydration, and rest.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

Lung diseases refer to a broad category of disorders that affect the lungs and other structures within the respiratory system. These diseases can impair lung function, leading to symptoms such as coughing, shortness of breath, chest pain, and wheezing. They can be categorized into several types based on the underlying cause and nature of the disease process. Some common examples include:

1. Obstructive lung diseases: These are characterized by narrowing or blockage of the airways, making it difficult to breathe out. Examples include chronic obstructive pulmonary disease (COPD), asthma, bronchiectasis, and cystic fibrosis.
2. Restrictive lung diseases: These involve stiffening or scarring of the lungs, which reduces their ability to expand and take in air. Examples include idiopathic pulmonary fibrosis, sarcoidosis, and asbestosis.
3. Infectious lung diseases: These are caused by bacteria, viruses, fungi, or parasites that infect the lungs. Examples include pneumonia, tuberculosis, and influenza.
4. Vascular lung diseases: These affect the blood vessels in the lungs, impairing oxygen exchange. Examples include pulmonary embolism, pulmonary hypertension, and chronic thromboembolic pulmonary hypertension (CTEPH).
5. Neoplastic lung diseases: These involve abnormal growth of cells within the lungs, leading to cancer. Examples include small cell lung cancer, non-small cell lung cancer, and mesothelioma.
6. Other lung diseases: These include interstitial lung diseases, pleural effusions, and rare disorders such as pulmonary alveolar proteinosis and lymphangioleiomyomatosis (LAM).

It is important to note that this list is not exhaustive, and there are many other conditions that can affect the lungs. Proper diagnosis and treatment of lung diseases require consultation with a healthcare professional, such as a pulmonologist or respiratory therapist.

"Bronchi" are a pair of airways in the respiratory system that branch off from the trachea (windpipe) and lead to the lungs. They are responsible for delivering oxygen-rich air to the lungs and removing carbon dioxide during exhalation. The right bronchus is slightly larger and more vertical than the left, and they further divide into smaller branches called bronchioles within the lungs. Any abnormalities or diseases affecting the bronchi can impact lung function and overall respiratory health.

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

Tobacco is not a medical term, but it refers to the leaves of the plant Nicotiana tabacum that are dried and fermented before being used in a variety of ways. Medically speaking, tobacco is often referred to in the context of its health effects. According to the World Health Organization (WHO), "tobacco" can also refer to any product prepared from the leaf of the tobacco plant for smoking, sucking, chewing or snuffing.

Tobacco use is a major risk factor for a number of diseases, including cancer, heart disease, stroke, lung disease, and various other medical conditions. The smoke produced by burning tobacco contains thousands of chemicals, many of which are toxic and can cause serious health problems. Nicotine, one of the primary active constituents in tobacco, is highly addictive and can lead to dependence.