Biotechnological Applications in Medicine
A modern hospital can make use of variety of sophisticated instruments and equipment of accurate diagnosis and treatment of diseases. Three main categories of instruments and equipment used are diagnostic, imaging, and therapeutic.
Diagnostic Instruments
(1) Sphygmomanometer
(i) Sphygmomanometer, commonly called B.P. Apparatus, is an instrument for measuring blood pressure.
(ii) This instrument consists of a rubber cuff attached by a rubber tube to a compressible hand pump or bulb.
(iii)ਊnother tube attaches to the cuff and to a column of mercury or pressure dial marked off in millimeters.
(iv) Blood pressure is usually taken in the left brachial artery.
(v) Blood pressure is recorded by giving the systolic pressure and diastolic pressure expressed as millimeters of mercury (mm Hg).
(vi) A healthy young adult male has blood pressure reading of about 120/80 (i.e. 120 mm Hg systolic and 80 mm Hg diastolic).
(vii) The difference between systolic and diastolic pressure is called Pulse pressure.
(viii)lood pressure often rises normally with age to about 130/90 at age 60.
(ix) Abnormally high blood pressure is known medically as hypertension abnormally low blood pressure is termed hypotension.
(2) Electrocardiograph
(i) The abbreviation ECG stands for electrocardiogram, a record of myoelectrical changes that immediately precede contraction of heart muscle.
(ii) Electrocardiograph is the instrument used to record ECG.
(iii) Leads from this instrument are attached to the chest, wrists and ankles using conducting jelly.
(iv) The waves produced in ECG are known as P, Q, R, S and T.
(v)ਊn ECG is helpful for diagnosing pathological disorders of the heart like coronary artery disease, coronary thrombosis, pericarditis, cardiomyopathy and myocarditis.
Multi-channel monitors measure and display the ECG, blood pressure in various heart chambers and other physiological data.
Echocardiography is a method of obtaining an image of the structure of heart using ultrasound.
Doppler echocardiography is a technique which allows the indirect measurement of the flow of velocity as it passes through the heart.
(3) Electroencephalograph
(i) The electrical activity of the exposed animal brain was discovered by Satton in 1875.
(ii) Hans Berger (1929) was the first to record Electro-Encephalo-Gram (EEG).
(iii)lectroencephalography is done by attaching a number of small electrodes to the scalp.
(iv) The electrodes are connected to an instrument that measures the brain&aposs impulses in microvolts and amplifies them for recording purposes.
(v)lectroencephalography is painless, produces no side-effects and to record it takes about 45 minutes.
(vi) An EEG records the minute electrical impulses produced by the activity of brain.
(vii) ꃮG is useful to find out whether the person is alert, awake or asleep.
(viii) EEG can help in diagnosing certain conditions such as epilepsy, encephalitis, dementia and brain tumour.
(ix) Electroencephalography can also be used to monitor the condition of patients during surgery and to assess the depth of anaesthesia.
(x)ꃮG is also used as a test for brain death.
(xi) The weaker magnetic fields from the brain can be studied with the help of SQUID (Super conducting Quantum Interference Device).
(xii) Magnetoencephalography (MET) is useful for studying the disease associated with the brain and spinal cord.
Imaging Instruments.
Major advancements in the medical sciences have been the development of new imaging techniques that provide detailed pictures of internal organs.
(1) X-rays
(i) ਏollowing their discovery by Wilhelm Roentgen, a German physicist in 1895, X-ray became an important tool for medical diagnosis.
(ii) X-ray are a form of electromagnetic radiation of extremely short wavelength.
(iii) When a beam of X-rays is directed at a part of the body such as chest, the rays are absorbed more by dense structures such as the ribs or heart muscles than by less dense structures such as the skin or lungs.
(iv) This causes shadows of variable intensity to be cast on a photographic film.
(v) X-rays cause no sensation when passed through body tissues.
(vi) Large or frequent radiation doses may damage the skin and internal organs and may cause cancer in later life.
(vii) The study of X-rays for detection and treatment of disease is called radiology.
(viii) X-ray imaging in the simplest form is commonly employedਏor diagnosing diseases of the heart, lungs and detection of bone and joint injuries.
(ix) Nowadays, the risk involved in having X-rays is extremely small radiation doses are kept to a minimum.
(2) Computed Tomographic Scanning (CT)
(i) T scanning was developed by Godfrey Hounsfield of Britain in 1968 (Nobel Prize in 1979).
(ii) This technique combines the use of X-rays with computer technology to produce a two or three-dimensional clear cross-sectioned image of an area.
(iii)omputed tomographic scanning is also known as CAT (Computed Axial Tomography).
(iv) CT scanning provides clearer and more detailed information than X-rays.
(v)ਊnother advantage of CT scanning is that it tends to minimize the amount of radiation exposure.
(vi) CT scanning can be used to obtain images of any part of the body.
(vii)T scanning helps in the diagnosis of diseases of brain, spinal cord, chest and abdomen.
(viii) This technique is also extremely useful in detecting tumour and monitoring the extent of their spread to surrounding tissues and organs.
(3) Positron Emission Tomographic Scanning (PET)
(i) PET scanning was developed by Louis Sokoloff of USA in 1985.
(ii) PET is a diagnostic technique based on detection of positrons (positively charged electrons) emitted by radio isotopes such as carbon 11, nitrogen 13 or oxygen 15 generated by the cyclotron.
(iii) These radio isotopes are then incorporated by chemical methods into biological molecules such as glucose, amino acids, carbon dioxide and ammonia.
(iv) These positron emitting compounds are injected into the blood-stream and are taken up in greater concentration by areas of tissues that are more metabolically active.
(v) PET scanning provides three- dimensional images that reflect the metabolic and chemical activity of tissues beings studied.
(vi) PET scanning is particularly valuable for measurement of regional cerebral blood volume, blood flow, metabolic rates of glucose and oxygen in humans.
(vii) PET scanning is used for detecting tumours, for locating the origin of epileptic activity within brain and for examining brain function in various mental illnesses.
(viii) Recently PET scanning has been used to locate colour-processing centers in human visual cortex.
(4) Magnetic Resonance Imaging (MRI)
(i) MRI was originally discovered in 1946 independently by Felix Bloch and Purcell in USA.
(ii) MRI is a diagnostic technique that provides high-quality cross-sectioned or three-dimensional images of organs and structures without using X-rays or other radiation.
(iii) This technique exploits the natural behaviour of the protons (nuclei) of hydrogen atoms when they are subjected to a very strong magnetic field and radio waves.
(iv) The most abundant source of protons in the body are hydrogen atoms in water molecules.
(v) An MRI scan reflects differences in the water content of tissues.
(vi) A newer application of MRI known as Nuclear Magnetic Resonance spectroscopy (NMR) relies on the detection of other chemical elements such as phosphorus and calcium.
(vii) The patient lies down surrounded by massive electromagnets and is exposed to short bursts of powerful magnetic field and waves.
(viii) The bursts stimulate protons (hydrogen nuclei) in the patient&aposs tissues to emit radio signals.
(ix) The signals are detected and analyzed by a computer to create an image of a “slice” of the patient&aposs body.
(x) In imaging NMR is superior to CT scanning it generally gives much greater contrast between normal and abnormal tissues, it is free from radiation hazards and images can be obtained in any plane unlike CT, which is restricted to cross-sectional imaging.
(xi) There are no known risks or side effects of MRI.
(xii) MRI is a costly test that is not yet widely available.
(xiii) MRI is especially useful in studying brain and spinal cord. It can clearly differentiate between white and gray matter.
(5) Ultrasound Scanning
(i) This is also known as echography or sonography and uses inaudible high-frequency sound waves in the range of 1-15 million hertz.
(ii) Ultrasound waves are produced by the piezoelectric effect when an electric potential is applied to crystals of lead zirconate.
(iii) Ultrasound waves are emitted by a device called a transducer which is placed on the skin over the part of body to be viewed.
(iv) The transducer contains the crystals of lead zirconate that converts an electric current into sound waves.
(v) The transducer crystal is made to oscillate back and forth.
(vi) Some of the waves are reflected at tissue boundaries, so a series of echoes are returned.
(vii) The transducer also actsਊs a receiver, converting these echoes into electrical signals, which are processed and displayed on a screen of a monitor to give a two-dimensional image.
(viii) Ultrasound imaging is useful in diagnosing the diseases of the brain, kidney stones, gallstones, cirrhosis, intestinal obstruction, fallopian tubes, uterus etc.
(ix) Ultrasound has wide applications in medicine and is especially useful in obstetrics.
(x) This technique offers no known risk to the baby and is often performed at about 16 to 18 weeks to reveal multiple pregnancy and foetal abnormalities like anencephaly and spina bifida.
Therapeutic Instruments.
Pacemakers
(1) Pacemaker is a device that supplies electrical impulses to the heart to maintain the heartbeat at a regular rate.
(2) The artificial pacemaker was introduced by Chardack in 1960.
(3) Pacemakers are life saving when the normal heart rate 72-80 drops to abnormally low levels like 30-40 due to diseases.
(4) Pacemaker consists of a pulse generator and an electrode.
(5) The pulse generator is hermetically sealed box it contain lithium halide cells to provide power for over 10 years.
(6) The electrode is a fine metallic spring ensheathed in a thin layer of biocompatible plastic the special tip remains in contact with the interior of right ventricle.
(7)ਊn artificial pacemaker is implanted when a person&aposs sinu-atrial node is not functioning properly.
(8) Two basic types of pacemakers are fixed-rate and demand type.
(9)ਏixed-rate pacemaker discharges impulses at a steady rate, irrespective of the heart&aposs activity.
(10) Demand pace maker discharges impulses only when the heart-rate slows or a beat is missed. A normal heart-rate and beat suppresses the pacemaker.
(11)ਊ pacemaker may be external (worn on belt) or internal (implanted in the chest).
(12) There are two main types of implantation, transvenous implantation and epicardial implantation.
(13) Modern pacemakers are comparatively insensitive to interference, but may be affected by powerful electromagnetic pulses.
(14) Anyone fitted with a pacemaker should avoid powerful radio or radar transmitters and should not pass through security screens at airports.
(15) Pacemakers are likely to be influenced by microwave ovens, electric shavers, automobile ignition and cellular phones.
Devices
Three types of medical devices used nowadays are implants, disposables and external prosthesis.
(1) Implants
Implants are devices used for replacng a diseased organ or tissue within the body.
Implants must be non-toxic and biocompatible and are used for replacing joint, arteries, heart valves, etc., and occasionally helpful in cosmetic surgery.
Artificial Heart Valve
(i) ਊrtificial heart valves may be either mechanical or made of human or animal tissues.
(ii) Mechanical valves are made from special biocompatible plastics, metal alloys and ceramics.
(iii) Tissue valves are taken from cadavers of pigs or made from the pericardium of animals.
(iv) Mechanical valves develop tendency of clotting of blood, so the patient must have regular medication of anticoagulants.
(v) Tissue valves do not require anticoagulants, but they tend to calcify, particularly in young.
(2) Disposables
(i) Oxygenator
(a) The first open heart surgery was performed by Walton Lillehel (USA) in 1953 by meant of a procedure, called heart-lung bypass.
(b) Oxygenator is used in open-heart surgery to oxygenate the blood passing through the heart-lung machine.
(c) Oxygenator can be called as an artificial lung. Two common types of oxygenators currently used are bubble oxygenator and membrane oxygenator.
(d)ubble oxygenators are used for shorter operation whereas membrane oxygenators are more suitable for longer operations and for operation of infants.
(ii) Blood Bag
(a) Blood transfusion is required during surgery, following delivery, for bleeding diseases and after injury.
(b) Improper transfusion can cause reactions or transmit dangerous diseases such as hepatitis B and AIDS.
(c) Disposable blood bags reduce chances of spreading diseases.
(d) Though not prescribed for general use, perfluorocarbons can be used as blood substitute they dissolve and release oxygen.
(iii) Blood Dialyser (Artificial Kidney)
(a) Kidney dialysis machine was invented by Willem Kolff, a dutch scientist in 1945.
(b) A person requires artificial kidney when both of his kidneys fail.
(c) An artificial kidney can only reproduce the passive filtration process.
(d) The blood of the patient is passed through the disposable dialyser and is then returned to the body by the intravenous route.
(e) Haemodialysis means a technique used to remove waste products from the blood.
(f) The working of blood dialyser is based on the physical laws of diffusion and osmosis.
Ready to master Biotechnology and its Applications?
Take a full mock test, practice concept-by-concept, and get an AI-powered rank prediction — all on Fundamenthol.