Category Health and Medicine

            Pain is an alarm initiated upon tissue injury, carried along fairly specific nerves, and ultimately experienced according to the past experience of the sufferer. Our body has its own analgesics to relieve pain. They are a group of opiate proteins called endorphins with special pain-relieving properties. They are naturally found in the brain and are distributed throughout the nervous system. They bind to specific brain tissues involved in the perception of pain.

  All sensation from the body is carried through the spinal cord along the posterior route, says Dr. A.V. Srinivasan, an eminent neuro-physician. It consists of two divisions – medical and lateral. The medical division carries sensation such as pressure, vibration, movement, position and fine touch. The lateral division carries pain and temperature.

            When pain balms are rubbed, the pressure and movement sensations are produced in excess. This is turn sends more sensory input via the larger division of the posterior route which blocks the pain sensation through the lateral division of the posterior route to the spinal cord. The medial division blocks the pain sensation at the gate entry zone of the spinal cord. This mechanism of pain relief can be extended to acupuncture and never stimulations also, he says.

            Therapeutic measures relieve pain by increasing the level of endorphins. Pain balms generally contain 3 components – methyl salicylate, menthol and camphor. These are easily absorbed through the skin. Menthol is a white crystalline substance and a principal constituent of oil of peppermint.

            Role of the balm includes a local anesthetic effect which acts along peripheral nerve endings. These analgesics are chemically similar to endorphins and they relieve pain by binding to the same sites as endorphins. Experience of pain is psychological and subjective.

            Although these analgesics have a special pharmacological effect in relieving pain, it is actually the amount of pressure applied and the movement that plays a significant role. Also other measures that increase confidence also will ease pain.

            While methyl salicylate absorbed through the skin acts as an analgesic, menthol dilates the blood vessels. Because of the increased blood flow one gets a cool sensation in the balm- applied area. This is useful in case of headache and rheumatic pains. Camphor also acts as a rubefacient and mild analgesic.

When a person cries tear fluid is secreted by a lacrimal gland seen bulging the conjunctiva (muscous membrane covering the eyeball and lining the eyelids). This tear passes through numerous ducts into the conjunctival sac, aided by ocular muscle contraction. From there it reaches the lacrimal sac and through the lacrimal duct it is drained into the nasal cavity. (Lacrimal duct is an anatomical drainage canal connects the corner of the eye to the lower surface of the nasal cavity). When there is a sudden discharge of tear, as while crying, the fluid is pooled resulting in congestion.

            Another interesting fact is that Nature has provided a flap valve at the terminal part of the canal to prevent tear fluid from being pushed back by air, while sneezing or blowing.

A yawning is considered as a form of expression indicating boredom or a break in our train of thought. For many, it is relaxing or may occur in response to seeing someone else yawn. Nobody knows why one person yawning can cause others to yawn.

Scientists say that the question can also be asked of our primate relatives. They have presented evidence that yawns are contagious among monkeys, particularly with individuals of similar age and social status. This contagion is interpreted as a synchronization of activities ‘due to the imposition of wake-sleep rhythms on different individuals and to the attention they devote to each other’.

A yawning should be in a process of decreasing arousal according to them. If observed by other animals and if the observers arousal level becomes synchronized as a consequence the observers will also yawn. Accordingly, the yawn should be only a sufficient, not a necessary, factor in electing yawns from other group members.

Watching somebody taking a nap, in other words, might also induce a state of declining arousal and trigger yawns. One would expect observed yawns to be a more powerful stimulus, however, because another’s yawns might precipitate the observer attending to muscular tension in the facial muscles that can be dissipated by the yawn’s stretch. In addition one might expect observed stretches in general to be contagious, and yawns may thus be a particularly obvious example of the general behavioural synchrony of interact ants.

   In general, bacteria use a number of different genetic mechanisms to develop, optimize and spread the genes that give them resistance. This includes the following:

• They suddenly change their genetic information (mutation).
• They exchange plasmids. Plasmids are additional, ring-shaped deoxyribonucleic (DNA) structures in bacterial cells.
• They spread by cloning. This means that they reproduce one cell whose daughters are transferred from one person to another.

Resistance genes develop when genes in the bacterial chromosome are modified by mutation. This generally requires more than one step. Mutation normally has to take place in several genes to achieve clinically effective resistance.

The selection caused by the way antibiotics are used is contributing to the rapid pace with which resistance is increasing. Massive use of certain antibiotics can lead particularly quickly to the spread of resistant strains. Without the selection pressure exerted by antibiotics, resistance genes could develop but they would never be able to spread sufficiently to gain dominance. Individual bacteria can only become dominant if they enjoy a persistent selective advantage over the rest of the bacterial population.

            Cloning is the process of ‘deriving’ an organism or a group of cells from another organism or from a single cell asexually. Members of a clone are identical in their inherited characteristic that is, in these genes except for any differences caused by mutation. Identical twins who originate by the division of a single fertilized egg are members of a clone, whereas non identical twins that derive from two separate fertilized eggs are not, according to the Encyclopedia.

            Through recent advances of genetic engineering, scientists can isolate one or more genes from one organism and grow it in another organism belonging to a different species. The species chosen as a recipient is usually one that can reproduce asexually, such as a bacterium or yeast. Thus it is able to produce a clone of organisms, or of cell, that all contain the same foreign gene or genes. They make many copies of a particular gene.

            The copies can then be isolated and used to study. As this procedure involves clones of organisms or cells it is called cloning.

Identical twin animals can also be produced by cloning. An embryo in the early stage or development is removed from the uterus and split, and then each separate part is placed in a surrogate uterus. This method has been used to produce mice and sheep.

 Another development has been the discovery that a whole nucleus, containing an entire set of chromosomes, can be taken from a cell and injected into a fertilized egg whose own nucleus has been removed. The division of the egg brings about the division of the nucleus, and the descendant nuclei can, in their turn, be injected into eggs.

 After several such transfers, the nuclei may become capable of directing the development of eggs into complete new organisms genetically identical to the organism from which the original nucleus was taken. This cloning technique is thus, capable of producing large numbers of genetically identical individuals. Such experiments have been carried out with frogs, mice and now with sheep and monkey. 

Keloid is a scar that does not know when to stop forming, becoming large, shiny, smooth, and often pink and dome-shaped, according to The Merck Manual of Diagnosis and Therapy. It is not known why some people get overgrown scars after injuries, surgery or acne, but keloids are more common among people of black and Asian descent, so a genetic factor is suspected.

In normal scarring, after the inflammation that follows an injury subsides, scar tissue begins to form, along with tiny new blood vessels.

Cells in the skin around the injury, called fibroblasts, produce collagen, a fibrous connective tissue. As more and more of the fibers link up, the scar becomes harder. In a keloid, the process continues long after the wound is covered over, and the scar can become quite large.

Keloids are not dangerous but can be disfiguring, tender and sometimes itchy. Removal of a keloid by surgery or the use of lasers, followed by corticosteroid injections at the site, is sometimes but not always successful, and can cause even worse scarring.

            Someone with a tendency to form keloids may want to avoid plastic surgery, though doctors can sometimes use hidden incisions in facial surgery or avoid making cuts in the periphery of the face, where keloids are more likely to form.