Critical review of Rheumatoid arthritis Essay Example | Topics and Well Written Essays - 1500 words

Critical review of Rheumatoid arthritis - Essay Example However, RA involves an attack on the body by its own immune cells (auto-immune disease). Different cases may have different causes. Infectious, genetic, and hormonal factors may play a role. The disease can occur at any age, but it begins most often between the ages of 25 and 55. The disease is more common in older people. Women are affected 2.5 times more often than men. Approximately 1-2% of the total population is affected. The course and the severity of the illness can vary considerably. The onset of the disease is usually gradual, with fatigue, morning stiffness (lasting more than one hour), diffuse muscular aches, loss of appetite, and weakness. Eventually, joint pain appears, with warmth, swelling, tenderness, and stiffness of the joint after inactivity. Joint involvement in RA usually affects both sides of the body equally -- the arthritis is therefore referred to as symmetrical. Wrists, fingers, knees, feet, and ankles are the most commonly affected joints. Severe disease is associated with larger joints that contain more synovium (joint lining). When the synovium becomes inflamed, it secretes more fluid and the joint becomes swollen. Later, the cartilage becomes rough and pitted. The underlying bone eventually becomes affected. Joint destruction begins 1-2 years after the appearance of the disease. Characteristic deformities result from cartilage destruction, bone erosions, and tendon inflammation and rupture. A life-threatening joint complication can occur when the cervical spine becomes unstable as a result of RA. Other features of the disease that do not involve the joints may occur. Rheumatoid nodules are painless, hard, round or oval masses that appear under the skin, usually on pressure points, such as the elbow or Achilles tendon. These are present in about 20% of cases and tend to reflect more severe disease. On occasion, they appear in the eye where they sometimes cause inflammation. If they occur in the lungs, inflammation of the lining of the lung (pleurisy) may occur, causing shortness of breath. Anemia may occur due to failure of the bone marrow to produce enough new red cells to make up for the lost ones. Iron supplements will not usually help this condition because iron utilization in the body becomes impaired. Other blood abnormalities can also be found, for example, platelet counts that are either too high or too low. Rheumatoid vasculitis (inflammation of the blood vessels) is a serious complication of RA and can be life-threatening. It can lead to skin ulcerations (and subsequent infections), bleeding stomach ulcers (which can lead to massive hemorrhage), and neuropathies (nerve problems causing pain, numbness or tingling). Vasculitis may also affect the brain, nerves, and heart causing strokes, sensory neuropathies (numbness and tingling), heart attacks, or heart failure. Heart complications of RA commonly affect the outer lining of the heart. When inflamed, the condition is referred to as pericarditis. Inflammation of heart muscle, called myocarditis, can also develop. Both of these conditions can lead to congestive heart failure characterized by shortness of breath and fluid accumulation in the lung. Lung involvement is frequent in RA. Fibrosis of the lung tissue leads to shortness of breath and has been reported to occur in 20% of patients with RA. Inflammation of the

Developmental Biology Essay Example | Topics and Well Written Essays - 2250 words

Developmental Biology - Essay Example After certain number of divisions the macromeres give rise to a pair of blastomeres termed as teloblasts M, N, Q and O/P. It is from these teloblasts that the segments of the annelid are derived in the adult. To draw our fate map we used alkaline phosphatase to help in tracing out the cell lineage of many of the adult structures. Alkaline phosphatase being naturally present in a cell and was an ideal candidate as a marker to trace out the fate map. The blastomeres were injected with high concentrations of alkaline phosphatase and then allowed to develop into their corresponding adult structures. The annelid was then bathed with a colourless substrate which coloured on reacting with alkaline phosphatase. Using this we were able to show that the blastomere A, B & C most probably develops into the ectoderm. The blastomere D though proved to be the most vital with most of the endoderm and mesoderm structures being derived from it. We also show the individual fates of each of the teloblasts and by alternating the time of injecting alkaline phosphatase we were able to deduce many vital facts about metamerisation. From our study we came to the conclusion that most probably the segments are produced from the posterior to the anterior direction and that segmentation begins at a very early stage of asymmetric cell division of the teloblasts. Introduction: The phylum Annelid consists of many species that range from the humble earthworm all the way to the maligned leech, but one common feature that binds them all is their segmented body. This segmentation is termed as Metamerism and each ring like segment is called a metamere. In fact the word Annelid is derived from the Latin word Annelis meaning rings. The Annelid body can be further bisected into two equal halves implying that the body architecture is bilaterally symmetrical. Annelids are also triplobalstic i.e. the embryo has 3 distinct germ layers namely the mesoderm, endoderm and ectoderm. It is from these 3 distinct germ layers that all the organ systems arise. The ectoderm that forms the outer layer of the embryo produces the epidermis and the nervous system, the endoderm which forms the inner most layer of the embryo gives rise to the digestive system and its related organs and sandwiched in between the two layers is the mesoderm which produces the circulatory system, muscles a nd connective tissue. As the yolk in the Annelid embryo is equally spaced out a Holoblastic cleavage pattern is seen and thus the cleavage furrow extends through the entire egg. The cleavage pattern seen in Annelids is a Spiral Cleavage which is also seen in other organisms such as sea urchins. During the first of cleavage, the embryo is divided into 4 cells each of which is called a blastomere and are labelled as A, B, C and D. All the blastomeres are of equal size except for Blastomere D which is slightly larger than the rest. The second round of cleavage produces an unequal division of 4 large blastomeres called Macromeres and 4 smaller blastomeres called Micromeres. The macromeres are labelled as A1, B1, C1, and D1 and the micromeres are labelled as a, b, c, and d. The macromeres keep on dividing to produce more macromeres and micromeres and eventually the entire organism is formed. Of special note is the D1 blastomere which further divides to