Recombination And Genetic Linkage
The diploid nature of chromosomes allows for genes on different chromosomes to or be separated from their homologous pair during sexual reproduction wherein haploid gametes are formed. In this way new combinations of genes can occur in the offspring of a mating pair. Genes on the same chromosome would theoretically never recombine. However, they do, via the cellular process of . During crossover, chromosomes exchange stretches of DNA, effectively shuffling the gene alleles between the chromosomes. This process of chromosomal crossover generally occurs during , a series of cell divisions that creates haploid cells. , particularly in microbial , appears to serve the adaptive function of repair of DNA damages.
The first cytological demonstration of crossing over was performed by Harriet Creighton and in 1931. Their research and experiments on corn provided cytological evidence for the genetic theory that linked genes on paired chromosomes do in fact exchange places from one homolog to the other.
Genes generally their functional effect through the production of , which are complex molecules responsible for most functions in the cell. Proteins are made up of one or more polypeptide chains, each of which is composed of a sequence of , and the DNA sequence of a gene is used to produce a specific . This process begins with the production of an molecule with a sequence matching the gene’s DNA sequence, a process called .
And Heres What You Can Expect With Treatment Which Is Generally Either Long
One of the most important ways to treat asthma is to avoid being exposed to your triggers, Dr. Wilgus says. Of course, that can feel impossible if your trigger is something thats seemingly everywhere, like dust or pollen. Though you can definitely take steps to reduce your exposure to those, avoiding them entirely is tough. Luckily, there are medications that can help when youve done everything you can trigger-wise.
Asthma medications generally fall into two categories: long-term preventive medications and fast-acting drugs that can help when youre having an asthma attack or on your way to one. Long-term preventive medications like allergy medications and inhaled anti-inflammatory corticosteroids are designed to help control your asthma so youre less likely to have an asthma attack in the first place, the Mayo Clinic says. Quick-relief medications , like short-acting beta agonists that you use via an inhaler, can help relax your airways when theyre acting up enough that your asthma is noticeably worse.
Whatever you do, dont resign yourself to living with asthma symptoms like trouble breathing and coughing all the time. Asthma is a very controllable illness as long as the signs and symptoms are not ignored, Dr. Parikh says.
Asthma And Allergies Tend To Run In Families
If theres asthma, eczema, hay fever or other allergies in your family it makes asthma more likely.
If you have asthma yourself, your child is much more likely to have asthma too, particularly if both parents have asthma. Theres slightly more chance of asthma being passed on by the mother than the father.
The Right Medicine For You
Medicine treatment for asthma depends on your age and type of asthma, and how well the treatment is controlling your asthma symptoms.
- The least amount of medicine that controls the asthma symptoms is used.
- The amount of medicine and number of medicines are increased in steps. So if asthma isn’t controlled at a low dose of one controller medicine, the dose may be increased. Or another medicine may be added.
- If the asthma has been under control for several months at a certain dose of medicine, the dose may be reduced. This can help find the least amount of medicine that will control the asthma.
- Quick-relief medicine is used to treat asthma attacks. But if you need to use quick-relief medicine a lot, the amount and number of controller medicines may be changed.
Your doctor will work with you to help find the number and dose of medicines that work best.
What Does Reversibility Mean
Reversibility means that lung function improves after taking a medication that opens the airways.5 Reversibility is a sign of asthma.
To test whether the airway obstruction is reversible, spirometry is done before and after taking albuterol.5 If your FEV1 increases by 12% or 200 mL after taking albuterol, it means that the airway blockage is reversible.1 FEV1 is the amount of air you can forcefully exhale in one second.
Reducing The Burden Of Asthma
Asthma cannot be cured, but good management with inhaled medications can control the disease and enable people with asthma to enjoy a normal, active life.
There are two main types of inhaler:
- bronchodilators , that open the air passages and relieve symptoms; and
- steroids , that reduce inflammation in the air passages. This improves asthma symptoms and reduces the risk of severe asthma attacks and death.
People with asthma may need to use their inhaler every day. Their treatment will depend on the frequency of symptoms and the different types of inhalers available.
It can be difficult to coordinate breathing using an inhaler especially for children and during emergency situations. Using a spacer device makes it easier to use an aerosol inhaler and helps the medicine to reach the lungs more effectively. A spacer is a plastic container with a mouthpiece or mask at one end, and a hole for the inhaler in the other. A homemade spacer, made from a 500-ml plastic bottle, can be as effective as a commercially-manufactured inhaler.
Access to inhalers is a problem in many countries. In 2019, only half of people with asthma had access to a bronchodilator and less than one in five had access to a steroid inhaler in public primary health-care facilities in low-income countries .
How Asthma Is Treated
While there is no cure for asthma, there are a number of treatments that can help control the condition.
Treatment is based on two important goals, which are:
- relieving symptoms
- preventing future symptoms and attacks
For most people, this will involve the occasional or, more commonly, daily use of medications, usually taken using an inhaler. However, identifying and avoiding possible triggers is also important.
You should have a personal asthma action plan agreed with your doctor or nurse that includes information about the medicines you need to take, how to recognise when your symptoms are getting worse, and what steps to take when they do so.
These symptoms are often worse at night and early in the morning, particularly if the condition is not well controlled. They may also develop or become worse in response to a certain trigger, such as exercise or exposure to an allergen.
Read our page on the causes of asthma for more information about potential triggers.
Speak to your GP if you think you or your child may have asthma. You should also talk to your doctor or asthma nurse if you have been diagnosed with asthma and you are finding it difficult to control the symptoms.
How Is Airway Sensitivity Measured
It is possible to measure how sensitive your airways with a methacholine challenge.3 This test rules out conditions that mimic asthma, such as vocal cord dysfunction and other obstructive lung diseases, such as chronic bronchitis and emphysema. Finding out that you have sensitive airways helps to confirm the diagnosis of asthma.
How Do You Know If You Are Having An Asthma Attack
An asthma attack happens when the body is exposed to a triggerlike pollen or smokethat causes the airways to become inflamed and swollen.
Asthma attacks are uncomfortable to experience and can be frightening, especially for children. If you or someone you know is having any of the following symptoms, they may be having an asthma attack:
- Difficulty breathing
- Chest tightness or pain
- Coughing or wheezing
An asthma attack may go away after a few minutes with proper treatment, but symptoms can last longer and become life-threatening if untreated. Seek medical attention immediately if you or someone you know is having a severe asthma attack with one or more of the following symptoms:
- A feeling of panic about the asthma attack
- Pale and sweaty face
- Lips or fingernails that are turning blue
- No improvement in symptoms after using an inhaler
Chronic Obstructive Pulmonary Disease
People with , most commonly or , frequently have chronic shortness of breath and a chronic productive cough. An presents with increased shortness of breath and production. is a risk factor for ; thus this condition should be ruled out. In an acute exacerbation treatment is with a combination of , , and possibly .
Give Teens Extra Attention
Teens who have asthma may view the disease as cutting into their independence and setting them apart from their peers. Parents and other adults can offer support and encouragement to help teens stick with a treatment program. It’s important to:
- Help your teen remember that asthma is only one part of life.
- Allow your teen to meet with the doctor alone. This will encourage your teen to become involved in his or her care.
- Work out a daily management plan that allows a teen to continue daily activities, especially sports. Exercise is important for strong lungs and overall health.
- Talk to your teen about the dangers of smoking and drug use.
- Encourage your teen to meet others who have asthma so they can support each other.
What Is Asthma Symptoms Causes Diagnosis Treatment And Prevention
Asthma is a common chronic lung disease in which the lungs’ bronchial tubes, or airways, become inflamed.
Want to know more about asthma? Read on to learn what experts know about this breathing disorder, why some people develop it and others dont, lifestyle changes that can help you manage asthma, and how to avoid complications linked to the condition.
Can You Treat Asthma Without An Inhaler
Unfortunately, there is no other effective first aid treatment for asthma. Placing the victim in a comfortable position to aid their breathing and keeping them calm will help, but these first aid measures will not stop the swelling and inflammation of the small airways. The victim will require treatment to improve their breathing.
Diagnosing Asthma In Children Younger Than 6
It can be hard to tell whether a child under age 6 has asthma or another respiratory condition, because young children often cannot perform a pulmonary function test such as spirometry. After checking a childs history and symptoms, the doctor may try asthma medicines for a few months to see how well a child responds. About 40% of children who wheeze when they get colds or respiratory infections are eventually diagnosed with asthma.
A Flu Shot Is The Best Protection Against Flu
Flu vaccination is especially important for people with asthma because they are at higher risk of developing serious flu complications. Flu vaccines are updated each season to keep up with changing viruses. Also, immunity wanes over a year so annual vaccination is needed to ensure the best possible protection against flu. A flu vaccine protects against the flu viruses that research indicates will be most common during the upcoming season. This seasons flu vaccines have been updated from last seasons vaccines to better match circulating viruses. More information on why flu vaccines are updated annually is available: Vaccine Virus Selection, as well as this years flu vaccine composition.
Immunity from flu vaccination sets in after about two weeks after getting vaccinated.
What Is An Obstructive Lung Disease
Asthma is an obstructive lung disease. An obstructive lung disease is one in which airflow in the smaller airways is impeded or obstructed, making it difficult for you to exhale which can cause asthma. Basically, it is hard for the air to get out of your lungs.
In a person with obstructive lung disease, the lungs expand normally and the air usually has no problem traveling into the lungs. The problem starts because the air cannot get out through narrowed airways. It takes longer to breathe out than in.2 Before you have finished exhaling, you feel the need to inhale. When this happens usually during asthma attacks in people with severe asthma some air gets stuck in your lungs at the end of the breath. This is called air trapping.2 Air trapping makes it hard for the next breath to get in. Once this cycle starts, it becomes harder and harder to breathe.
How Can You Prevent Asthma Attacks
You can prevent some asthma attacks by avoiding those things that cause them. These are called triggers. A trigger can be:
- Irritants in the air, such as cigarette smoke or other kinds of air pollution. Don’t smoke, and try to avoid being around others when they smoke.
- Things you are allergic to, such as pet dander, dust mites, cockroaches, or pollen. When you can, avoid those things you are allergic to. It may also help to take certain kinds of allergy medicine.
- Exercise. Ask your doctor about using a quick-relief inhaler before you exercise if this is a trigger for you.
- Other things like dry, cold air; an infection; or some medicines, such as aspirin and other nonsteroidal anti-inflammatory drugs . Try not to exercise outside when it is cold and dry. Talk to your doctor about vaccines to prevent some infections. And ask about what medicines you should avoid.
Dna Sequencing And Genomics
, one of the most fundamental technologies developed to study genetics, allows researchers to determine the sequence of nucleotides in DNA fragments. The technique of , developed in 1977 by a team led by , is still routinely used to sequence DNA fragments. Using this technology, researchers have been able to study the molecular sequences associated with many human diseases.
As sequencing has become less expensive, researchers have of many organisms using a process called , which utilizes computational tools to stitch together sequences from many different fragments. These technologies were used to sequence the in the completed in 2003. New technologies are dramatically lowering the cost of DNA sequencing, with many researchers hoping to bring the cost of resequencing a human genome down to a thousand dollars.
came about due to the ever-increasing demand for low-cost sequencing. These sequencing technologies allow the production of potentially millions of sequences concurrently. The large amount of sequence data available has created the subfield of , research that uses computational tools to search for and analyze patterns in the full genomes of organisms. Genomics can also be considered a subfield of , which uses computational approaches to analyze large sets of . A common problem to these fields of research is how to manage and share data that deals with human subject and .
Drugs And Food Additives
Beta blockers, which often are prescribed for high blood pressure, glaucoma, migraine headaches and angina, can cause bronchospasm, an airway tightening. Patients with asthma should consult their allergist about the use of these medications.
Food additives rarely trigger asthma. The most common food trigger for asthma is sulfite, a preservative used in such products as frozen potatoes and some beers and wines.
Most People With Asthma Understand Asthma Triggers But What Causes Asthma In The First Place
Asthma occurs when certain cells of the body’s immune system misidentify substances as very harmful and overreact to them, causing the bronchial tubes in the lungs to become inflamed and narrowed. What causes asthmaand why it occurs in some people and not othershas long baffled medical experts. Still, a growing number of risk factors and asthma triggers have been identified, helping doctors to diagnose and treat people affected by the disease.
How do people get asthma? Here are 10 risk factors to assess your likelihood of developing asthma.
1. You’re overweight. You know obesity can increase your risk for arthritis, diabetes, stroke, and other health conditions, but did you know you can add asthma to that list as well? It’s true . It could be that excess weight presses on the lungs, triggering responses typical of asthma. It might also be that when someone is overweight, all their organs have to work harder, including their lungs.
2. You have skin allergies. Although skin allergies may not be what causes asthma, studies show that there is a correlation between skin allergies and asthma. In fact, children who have eczema and hay fever are nine times more likely to develop asthma as adults, and can later have asthma more severe and persistent.
6. You’re a boy.“Asthma occurs at all ages of life,” Kao says. However, the likelihood of having it does depends on age and gender. Before puberty, asthma is more common in males.
Medically reviewed in May 2018.
Exposure To Triggers At Work
Occupational asthma is a type of asthma caused by certain things found in the workplace, such as chemicals or dust from flour or wood.
If you havent had asthma before and then get it because of the work you do, and if your symptoms improve when youre not at work, you probably have occupational asthma.
Occupational asthma is a common cause of adult onset asthma.
Asthma Signs & Symptoms
People with asthma experience symptoms due to inflammation in the airways. They might only occur when you encounter an asthma trigger. Common symptoms that can lead to a diagnosis of asthma include:
- Persistent or recurring coughing: which often occurs at night or early in the morning, although it can happen at any time. Coughing is a major feature of asthma, especially in children and can sometimes be the only sign of asthma.
- Wheezing: is difficulty breathing accompanied by a whistling sound coming from your airways
- Shortness of breath: gives you the feeling that you cant get enough air into your lungs, and may even find it difficult to eat, sleep or speak
- Chest tightness: an unpleasant sensation of heaviness or pressure in the chest that can make it hard to breathe
- Increased mucus production: is characterized by high levels of thick fluid or phlegm accumulating in your airways
- Difficulty breathing while exercising: having trouble breathing while performing physical activities can be a sign of asthma
- Losing Sleep: Being unable to sleep through the night because of breathing troubles
Conditions Related To Asthma
Asthma can be associated with several other conditions and health problems. In some cases, asthma can increase the likelihood of certain illnesses, like:
Additionally, there are some illnesses and health conditions that appear to be linked to asthma in that people with one are more likely to have the other, like:
Learn about common asthma symptoms and treatments and a lot more from one of the countrys preeminent medical institutions. You can also connect with Mayo Clinic doctors and clinicians for treatment options.
What Else Should I Know
The best way to manage asthma is to prevent flare-ups. Do that by following your asthma action plan and avoiding triggers, taking any medicines your doctor prescribes as directed, and getting a flu shot each year.
Your doctor also may ask you to keep track of your asthma symptoms in an asthma diary. This can help the doctor track how you feel after taking medicines. Your doctor might also ask you to use a peak flow meter as a way to monitor your asthma.
Caring for asthma takes a bit of work. But if you follow your asthma action plan, take your medicines properly, recognize your symptoms and triggers, and check in with your doctor regularly, you can do anything that people without asthma do.
What Are Common Asthma Attack Triggers
An asthma attack happens when someone comes in contact with substances that irritate them. Healthcare providers call these substances triggers. Knowing what triggers your asthma makes it easier to avoid asthma attacks.
For some people, a trigger can bring on an attack right away. Sometimes, an attack may start hours or days later.
Triggers can be different for each person. But some common triggers include:
- Air pollution: Many things outside can cause an asthma attack. Air pollution includes factory emissions, car exhaust, wildfire smoke and more.
- Dust mites: You cant see these bugs, but they are in many homes. If you have a dust mite allergy, they can cause an asthma attack.
- Exercise: For some people, exercising can cause an attack.
- Mold: Damp places can spawn mold. It can cause problems for people with asthma. You dont even have to be allergic to mold to have an attack.
- Pests: Cockroaches, mice and other household pests can cause asthma attacks.
- Pets: Your pets can cause asthma attacks. If youre allergic to pet dander , breathing in the dander can irritate your airways.
- Tobacco smoke: If you or someone in your home smokes, you have a higher risk of developing asthma. The best solution is to quit smoking.
- Strong chemicals or smells.
With asthma, you may not have all of these symptoms. You may have different signs at different times. And symptoms can change between asthma attacks.
Bipoc Communities And Asthma
The causes driving these disparities are multifactorial.
“Poverty, exposure to pollution, and limited access to medical care play a big role in racial disparities in asthma,” says Kenneth Mendez, AAFA’s president and CEO.
“These factors are interrelated and intergenerational, he explains. Discriminatory housing policies, for example, have caused long-lasting residential segregation, in which poverty is concentrated in Black and Hispanic communities, which then perpetuates a cycle of limited access to education, employment, and quality healthcare services, he says. This residential segregation is also responsible for the disproportionate proximity of minority populations to sources of pollution, such as industrial centers, major roadways, oil and gas refineries, distribution hubs, and traffic-related pollution, which can put people at higher risk for asthma and having worse outcomes, Mendez explains.
Why Do People Get Asthma
Research has yet to show a definitive cause of asthma. However, researchers have determined several risk factors that can lead to asthma development.
Family History and Genetics
Children of mothers with asthma are three times more likely to suffer from asthma, and 2.5 times more likely if the father has asthma. More than 30 genes have been linked to asthma so far, and gene-gene interactions, gene-environment interactions and epigenetic modifications also play a part. Genetic differences also play a role in differences in response to treatment.
People are more likely to have asthma if they have certain types of allergies, such ones which can affect the eyes and nose. However, not everyone who has allergies will get asthma and not everyone who has asthma is affected by allergies. Respiratory allergies and some types of asthma are related to an antibody called immunoglobulin E , which the immune system produces in response to allergens. To protect the body, the IgE causes allergic reactions that can affect the eyes, nose, throat, lungs and skin.
Children born before 37 weeks are at increased risk of developing asthma later in life.
Babies or small children may be at risk of developing asthma later in life if they had certain lung infections at a very early age.
Women can develop adult-onset asthma during or after menopause.
Environment Air Quality
What Causes An Asthma Attack
An asthma attack can happen when you are exposed to asthma triggers. Your asthma triggers can be very different from someone elses asthma triggers. Know your triggers and learn how to avoid them. Watch out for an attack when you cant avoid your triggers. Some of the most common triggers are tobacco smoke, dust mites, outdoor air pollution, cockroach allergen, pets, mold, smoke from burning wood or grass, and infections like flu.
When To Call A Doctor
- You are having severe trouble breathing. Signs of this include:
- Breathing very fast. Shortness of breath can interfere with the ability to speak smoothly.
- Appearing anxious and being unable to eat because it’s too hard to breathe.
- Using the neck, chest, and belly muscles to breathe so that the skin between, above, and under the ribs sinks inward with each breath. Your nostrils may open wide when you breathe in.
- Taking longer than usual to breathe out and sometimes having a high-pitched, musical sound when breathing in.
- Sitting up, leaning forward, or sitting with your nose tilted up as if sniffing the air.
- Having skin color that stays pale, gray, bluish, or mottled, including the tongue, lips, earlobes, and nail beds.
- Your symptoms do not get better after you have followed your asthma action plan.
- You have new or worse trouble breathing.
- Your coughing and wheezing get worse.
- You cough up dark brown or bloody mucus .
- You have a new or higher fever.
- You need to use quick-relief medicine on more than 2 days a week within a month .
- You cough more deeply or more often, especially if you notice more mucus or a change in the color of your mucus.
- You have asthma and your peak flow has been getting worse for 2 to 3 days.
If you have not been diagnosed with asthma but have mild asthma symptoms, call your doctor and make an appointment to be checked.