DMD Flashcards
ACE inhibitors
ACE inhibitors block the action of the enzyme ACE in the blood. ACE converts angiotensin 1 to angiotensin 2 which encourages blood vessels to constrict. The absence of them encourages dilation. ACE inhibitors block the formation of angiotensin 2.
Vasodilators
A drug that widens blood vessels. They are most predominantly used to reduce blood pressure and narrowed vessels. Therefore they improve blood flow, increasing oxygen supply and put less strain on the heart. Vasodilators dilate the blood vessel by relaxing the muscle around the vessel, by ACE inhibitors or by angiotensin 2 blockers.
Why does vasodilators affect DMD?
DMD can lead to cardiomyopathy (disease to the heart wall) that is caused by mutations in the DMD gene. The heart becomes weakened so doesn’t pump blood as efficiently. Vasodilators prevent tightening of muscles and narrowing vessel walls which helps improve blood flow.
Beta blockers function
They block the adrenal gland so they interrupt the transmission of stimuli through the beta receptors in the body. Signals from the sympathetic nervous system are carried by noradrenaline, a neurotransmitter produced by the adrenal gland and at the end of sympathetic nerve fibres. Beta blockers stop this transmission.
Beta blockers treat…
Arrhythmias, hypertension, tachycardia so slows down the heart and dilated the blood vessel. They can also be prescribed to improve heart wall function or to reduce symptoms of an overactive thyroid gland.
Beta blockers side affects
They are the same shape to fit the beta receptors in the lungs which can lead to breathing difficulties. The slower heart rate can reduce circulation leading to cold hands and feet.
How do beta blockers help DMD?
They allow the heart to beat slower with less force which leads to blood vessel dilation. This helps to lower the blood pressure and put less strain on the heart. This helps to increase the time at which the body can cope with cardiomyopathy.
DMD
A type of muscular dystrophy. A genetic disease causing muscle wastage and weakness. Suffers have a fault (mutation) on their dystrophin gene. This leads to dystrophin not being produced which is a protein that protects muscles.
Dystrophin
It is within muscles as part of a group of proteins that strengthens muscle fibres. This helps to protect you from injury as muscles contract and relax.
Cardiomyopathy
A general term for diseases of the heart muscle. The walls of the chambers become stretched, thickened or stiff. This affects the heart ability to pump blood around the body.
Recessive
To have it two faulty genes need to be present in female and one in male. Lower case marker. Effects the x chromosome.
Homozygous
Both are the same eg. Both dominant or both recessive
Heterozygous
One of each eg. One dominant one recessive
Phenotype
Characteristic caused by genotype
Eg. Healthy or affected
Alleles
Alternate versions of the same gene (one per gene)
Gamete
One from each parent. A circle denotes it is a gamete
Genotype
The combination of alleles an individual has.
Full blood count
Full blood count also known as a haematology profile examines the components of the blood. Often highly automated and uses special equipment in a lab. It involves measuring: erythrocyte, leukocyte and thrombocyte count per mm of blood. The size of the erythrocyte, mean size in a sample, the proportion of the blood made up by erythrocytes (haematocrit) and the amount of haemoglobin in erythrocytes. The amount of different types of leukocytes can be calculated to look at the bodies ability to fight infection. Thrombocyte count can show the bodies ability to clot blood.
Testing for creatine kinase
Full blood count
An enzyme catalyzing the conversion of ATP to ADP to release energy. High levels show signs of dmd. It leaks out damaged muscles into the blood.
Echocardiogram
A type of ultrasound that looks at the heart and the blood vessels nearby. Small probes send out high frequency sound waves that create echoes when they bounce off different parts of the body. These echoes are picked up off probes and turned into moving image on a monitor while the scan is carried out. Cardiomyopathy can be detected.
EMG - electrical test on nerves and muscles
Records electrical impulses that the muscle produces and the speed it travels along a nerve. Sensors are placed on the skin. DMD don’t respond well to EMG impulses.
Muscle biopsy
Minor surgical procedure removing a small but of muscle to be examined. Helps to rules out inflammation or other diseases.