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| Sunday, 22 January 2006 |
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Features |  |
| News Business Features Editorial
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Health Guide
Care of normal skin : Mirror, mirror on the wall... Dr. Mahinda de Silva It is often said that the best skin care is no care. Though this is not strictly true, care of normal skin is much simpler than the myriad of fantastic advertisements for skin care products. Good scientific studies regarding the care of normal skin are rudimentary and few. "Normal" skin is skin that is not affected by any disease process.
It is not at all proven that normal skin benefits at all from anything except protection from harsh chemical and physical agents, especially sunlight. On the other hand many skin care and cosmetic products can cause inflammation of the skin (eczema, dermatitis) from contact with irritants, allergens, sometimes after exposure to sunlight. The latter are referred to as (phototoxic) light toxic and (photo allergic) light allergic reactions. Some individuals are believed to have "sensitive skins" There are many unknown factors including, inherited factors, gender, age and race differences and other skin attributes that affect their immune system and the protective skin barrier, making them more susceptible to skin irritation. However, many individuals consider themselves to have sensitive skin because they experience stinging, burning, redness or tightness immediately following product application or up to several hours or days. These symptoms may only appear after several applications or after a combination of products have been applied one after another. Approximately half have no visible signs of skin inflammation. It will be useful at this point to enumerate some details pertaining to the structure and functions of the skin. The basic structure of the skin consist of two layers, the epidermis and the dermis which rests on subcutaneous fat. The epidermis The epidermis has four layers the outermost, the stratum corneum being in contact with the external environment. The thickness of the epidermis varies with age, sex, and the location on the body. For example, the epidermis on the underside of the forearm is about 5 cell-layers thick. On the sole of the foot, the epidermis might be 30 cell-layers thick. The stratum corneum, in which the cells are for the most part dead, consist of the protein Keratin, which is specific to the skin, hair and nails. This acts as a semi permeable barrier. The epidermis has three principal functions: Protecting the body from the environment, particularly ultraviolet radiation, the sun ultraviolet. Part of this radiation is reflected by the stratum corneum at the skin surface, part is absorbed by the melanin in the epidermal cells, and some are scattered within the skin. This scattered radiation creates a lot of high-energy particles, which are called free radicals. Free radicals are very reactive, and attack the constituents of the skin: this is why over a long time ultraviolet radiation produces so much damage Preventing excessive water loss from the body, for which the stratum corneum is very important. Barrier function which among other things protects the body from infection. The lower layer is called the dermis. This layer is composed of connective tissue, blood vessels, nerve endings, hair follicles, and sweat and oil glands. Skin Glands Sebaceous glands: These glands produce sebum, an oily substance that also contains waxes and lipids. Sebaceous glands are embedded in the dermis over most of the body. They are more concentrated in the scalp, face and forehead. They are not found in the palms or soles. Sebaceous glands begin to function at puberty, when the male and female reproductive hormones kick in. Sebum may have weak antibacterial and antifungal properties. Disruption in the normal, continuous flow of sebum is one of the causes of acne ("pimples"). Acne is an inflammation of obstructed sebaceous glands. Sweat Sweat glands secrete mostly water, sodium chloride (salt), urea, ammonia, and uric acid, the waste products of protein metabolism. Sweat glands are coiled, tubular glands. Their ducts open at the skin's surface, similar to the opening of a hair follicle. The glands secrete sweat for three main purposes: to moisten skin, to excrete waste, and to regulate body temperature. Once secreted onto the surface of the skin, the sweat evaporates, cooling the surface. Sweat glands receive messages from the nervous system. These messages can alter the production of sweat. For example, sweating can be increased by being nervous or by eating spicy foods. A second type of sweat is present in the armpit, nipple, and anal regions. These glands open into a hair follicle, rather than directly onto the skin's surface. These glands produce a thick secretion that is odourless. In general, this type of sweat becomes obnoxious (smelly) because of bacteria that normally colonize those areas. As mentioned earlier, categorization into "skin types", have no basis in fact, and are useful only to the cosmetic company which is recommending the product. The principles of skin care apply to normal skin irrespective of it being "dry" or "oily". Skin at different ages Infants: By the age of 10-14 days, the skin of even the youngest premature babies has begun to function as a reasonable barrier to fluid and heat losses, and is less permeable to substances applied to its surface. Infant skin has only about half the thickness of adult skin, and the epidermis is more loosely attached to the dermis. Therefore it blisters and abrades more easily. Children Children's skin does not need moisturizing unless there is xerotic(dry) skin (associated with atopy or eczema), or after prolonged exposure to sun or sea, but regular protection against the sun should begin now. There is often massive exposure to the sun during childhood, which will have long-term consequences. The care of the skin of small children is almost entirely in the hands of parents or guardians. Nevertheless it is never too soon for them to begin to learn about skin care. It is vital to protect the skin of children against the sun, especially those with light skin, against sunburn, to prevent the development of unpleasant skin changes including cancer in later life. Adolescents At puberty adolescents produce male hormones, called androgens. Under the influence of these androgens the skin produces more oil (sebum) and in most teenagers there is a tendency for acne to develop. These can be anything from simple blackheads to large pustules. Caring for teenagers' skin is a matter of balancing the cleansing and toning needed to remove the excess oil with adequate moisturizing to combat the potential over-drying effects of this cleaning. Teenagers' skins tend to hold water well, so they need far lighter moisturizers than those formulated for more elderly people, whose skin tends naturally to be dry. In fairer skinned adolescents, even at this age, cleansing and moisturizing products should contain ingredients that screen against ultraviolet light (UVA and UVB). Ageing skin The age of an individual appears to be dependant on many factors. Genes are important, but even more crucial is the way the skin and body are treated throughout life. After the 'bloom of youth' fades, the skin begins to lose its ability to retain moisture. It becomes drier and flakier, and shows the results of exposure to the environment, accumulated over many years. As we grow older, we see and feel certain changes in our skin, which is the body's largest and most visible organ. The skin becomes drier, more wrinkled, and spots and growths appear. Also, after an injury our skin tends to heal more slowly. Some of these skin changes are natural, unavoidable, and harmless. Others are itchy or painful, and some changes, such as skin cancers, are serious and require medical attention. Many of these skin problems can be prevented. Whether a danger to health or merely cosmetically unattractive, most of these skin problems can be addressed by therapies now available. Consumers are safe to consume chicken, eggs Cont. from last week by Dr. Keerthi Gunasekara The disease in turkeys is similar to that seen in layers, but it lasts 2 or 3 days longer and is occasionally accompanied by swollen sinuses. In domestic ducks and geese the signs of depression, inappetence, and diarrhoea are similar to those in layers, though frequently with swollen sinuses. Younger birds may exhibit neurological signs. Plague, occurred after a serologically identical but apparently mild virus had been circulating in poultry in the area for 6 months. Outbreaks of less virulent AI have frequently been described in domestic ducks in many areas of the world. The AI viruses are often recovered from apparently healthy migratory waterfowl, shore birds, and sea birds worldwide. The epidemiologic significance of these isolations relative to outbreaks in domestic poultry has led to the generally accepted belief that waterfowl serve as the reservoir of influenza viruses. There is a considerable body of circumstantial evidence to support the hypothesis that migratory waterfowl, sea birds, or shore birds are generally responsible for introducing the virus into poultry. Once introduced into a flock, the virus is spread from flock to flock by the usual methods involving the movement of infected birds, contaminated equipment, egg flats, feed trucks, and service crews, to mention a few. Preliminary trapping evidence indicates that garbage flies in the Pennsylvania outbreak were sources of virus on the premises of the diseased flocks. Virus may readily be isolated in large quantities from the feces and respiratory secretions of infected birds. It is logical to assume, therefore, that because virus is present in body secretions, transmission of the disease can take place through shared and contaminated drinking water. Airborne transmission may occur if birds are in close proximity and with appropriate air movement. Birds are readily infected via instillation of virus into the conjunctival sac, nares, or the trachea. Preliminary field and laboratory evidence indicates that virus can be recovered from the yolk and albumen of eggs laid by hens at the height of the disease. Birds that die with the per acute disease and young birds may not have significant gross lesions other than severe congestion of the musculature and dehydration. In the less acute form, and in mature birds, significant gross lesions are frequently observed. They may consist of subcutaneous edema of the head and neck area, which is evident as the skin is reflected. Fluid may exit the nares, an oral cavity, as the bird is positioned for postmortem examination. The conjunctivae are severely congested - occasionally with petechiation. The trachea may appear relatively normal except that the lumen contains excessive mucous exudates. It may also be severely involved with haemorrhagic tracheitis similar to that seen n with infectious laryngotracheitis. When the bird is opened, pinpoint petechial haemorrhages are frequently observed on the inside of the keel as it is bent back. Very small petechia may cover the abdominal fat, serosal surfaces, and peritoneum, which appears as if it were finely splattered with red paint. Kidneys are severely congested and may occasionally be grossly plugged with white urate deposits in the tubules. In layers, the ovary may be haemorrhagic or degenerated with darkened areas of necrosis. The peritoneal cavity is frequently filled with yolk from ruptured ova, causing severe airsacculitis and peritonitis in birds that survive for 7 to 10 days. Haemorrhages may be present on the mucosal surface of the proventriculus - particularly at the juncture with the gizzard. The lining of the gizzard peels easily and frequently reveals haemorrhages and erosions underneath. The intestinal mucosa may have haemorrhagic areas - especially in the lymphoid foci such as the cecal tonsils. The gross lesions are not distinctly different from those observed with Velogenic Viscerotropic Newcastle disease (VVND). The lesions in turkeys and domestic ducks are similar to those in chickens but may not be as marked. The prognosis for flocks infected with HPAI is poor. Morbidity and mortality rates may be near 100 percent within 2 to 12 days after the first signs of illness. Birds that survive are usually in poor condition and resume laying only after a period of several weeks. The practice of accepted sanitation and bio-security procedures in the rearing of poultry is of utmost importance. In areas where waterfowl, shore birds, or sea birds are prevalent, the rearing of poultry on open range is incompatible with a sound AI prevention program. Appropriate bio-security practices should be applied, including the control of human traffic and introduction of birds of unknown disease status into the flock. Proper Cleaning and disinfection procedures should be applied. Direct control 1. Do not visit any infected poultry operations while in above reported countries on holidays. 2. Apply proper quarantine methods. 3. Avoid contact with wild migratory waterfowl. Treat water near barns with chlorine, if possible. 4. Constant surveillance programs implemented in each province. Department of Animal Production and Health has taken some preventive measures together with government and the private sector veterinarians and All Island Poultry Association. 5. Governments should have plans for rapid implementation programs to face, control and eradicate lethal Avian Influenza. 6. Educational programs implemented to inform growers and support personnel about the threat of Avian Influenza. 7. Poultry industry should upgrade its bio-security practices and facilities to reduce the likelihood of disease agents being brought into flocks from other poultry or avian species. 8. Each province should determine, in advance, the methods that officials will be allowed to use in the dispensing of large numbers of poultry carcasses. Biosecurity Comparing other countries, Sri Lankan poultry mainly consist of chicken including broiler, a breeder population in which over 98% reared under intensive management system. So there is very less possibility to direct contact with wild birds. Still they have to improve their bio-security further. Poultry producers can reduce the risk of Avian Influenza introduction and spread by: 1. Manage poultry in 'all in all out' facilities; 2. Remove all organic matter and clean and disinfect houses between flocks; 3. Keep out unauthorised persons, lock doors, post no admittance signs; 4. Wear sanitised boots, clean clothing and head gear in poultry houses; 5. Clean and disinfect motor vehicles prior to coming onto the premises; 6. Vector control: wild birds, animals and or migratory birds; 7. Advise employees to stay away from live bird markets or poultry flea markets; 8. Do not allow anyone on the premises that may have been in contact with flocks of ducks, geese or exotic birds. SLMA welcome proposed legislation The Sri Lanka Medical Association (SLMA) while pledging to support the proposed legislation to set up an authority to control tobacco, urges Sri Lankans to help the authorities to make it a reality. In a statement issued by the SLMA states that Sri Lanka is lagging behind in appropriate legislative enactment to implement provisions of WHO's Framework Convention on Tobacco Control (FCTC) which the country has already ratified. It further states that "This is a long overdue step. Sri Lanka took the lead in drafting such legislation and presented it to Parliament a few years or so ago. But this was not taken to the logical end. We are not aware of the influences that led to the proposed legislation being allowed to die a quiet death. It is good that similar legislation is now proposed, at least in the form of a private member's bill." The statement issued by the SLMA states: "The reasons for such legislation are not only medical. From the purely medical standpoint, however, the Medical Association is very pleased that the forgotten legislation has now resurfaced. The world has moved rapidly forward on the tobacco front in the last few years. The FCTC refers to legislation to control the promotion of tobacco and to other measures to limit its harm. These were approved in a global convention almost entirely because of the huge evidence of the health damage from tobacco use, especially smoking. On alcohol, the measures for control are much harsher in many countries. There is total prohibition imposed in several countries for additional cultural and religious reasons as well. But reduction in alcohol use is associated with health benefits to the population and there are no populations that have been proven to have improved health by increasing their alcohol consumption. Thus the proposed legislation should find strong support not only from the medical profession but also from all citizens interested in the welfare of the population at large. There is evidence that the economic and social harms from these substances is much larger on poorer sections of the population. Thus the concern about harm should come from those outside the health sector too, for this and many other social reasons. Just from the purely medical point of view too, the proposed legislation to restrict the promotion of tobacco and alcohol and to set up an authority to reduce harm from it, is likely to result in several thousands of lives being saved. The SLMA strongly supports it and urges all citizens to do their best to
ensure that this time too, the legislation is not made to die a natural
death. Sri Lanka must catch up with the rest of the world in taking active
measures to protect the lives of its citizens from entirely preventable
harm." |
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| Produced by Lake House |
Of course skin may vary in texture, appearance and complexion, but the
classifications and skin types in advertisements and beauty parlours are not
based on scientific principles or real life skin types, but on the product
of the company which is recommending the product. 
