إعـــــــلان

تقليص
لا يوجد إعلان حتى الآن.

إستكمال الأمراض المناعية عشان عيونك يا رنا

تقليص
X
 
  • تصفية - فلترة
  • الوقت
  • عرض
إلغاء تحديد الكل
مشاركات جديدة

  • إستكمال الأمراض المناعية عشان عيونك يا رنا

    السلام عليكم و رحمة الله و بركاتة و تحية عطرة أهديها للجميع

    إستكمالاً للأمراض المنا عية سأطرح اليوم موضوع عن CTD

    أرجوا أن تستفيدوا منه أترككم في آمن الله و حفظه

    محبتكم BEROOOO :more43:

    I LOVE IMMUNOLOGY
    الملفات المرفقة
    تواضع تكن كالنجم لاح لناظر على صفحات الماء وهو رفيع

    و لا تك كالدخان يعلو بنفسه على طبقات الجو و هو وضيع


    http://up1.m5zn.com/photo/2009/2/10/...okezwv.gif/gif

  • #2
    وعليييييييييكم السلام
    تسلملي عيونك
    يا اروع واحلا عضوة في المنتدى
    :more20:

    تعليق


    • #3
      Return to Encyclopedia Index S





      Definition

      Streptococcal infections are caused by a microorganism called Streptococcus. Three streptococcal antibody tests are available: the antistreptolysin O titer (ASO), the antideoxyribonuclease-B titer (anti-Dnase-B, or ADB), and the streptozyme test.

      Purpose

      The antistreptolysin O titer, or ASO, is ordered primarily to determine whether a previous group A Streptococcus infection has caused a poststreptococcal disease, such as scarlet fever, rheumatic fever, or a kidney disease called glomerulonephritis.

      The anti-DNase-B (ADB) test is performed to determine a previous infection of a specific type of Streptococcus, group A beta-hemolytic Streptococcus. Identification of infections of this type are particularly important in suspected cases of acute rheumatic fever (ARF) or acute glomerulonephritis.

      Streptozyme is a screening test used to detect antibodies to several streptococcal antigens. An antigen is a substance that can trigger an immune response, resulting in production of an antibody as part of the body's defense against infection and disease.

      Precautions

      For the ASO test, increased levels of fats, called beta lipoproteins, in the blood can neutralize streptolysin O and cause a false-positive ASO titer. Antibiotics, which reduce the number of streptococci and thereby suppress ASO production, may decrease ASO levels. Steroids, which suppress the immune system, consequently may also suppress ASO production. Also Group A streptococcal infections of the skin may not produce an ASO response. Antibiotics also may decrease anti-DNase-B (ADB) levels.

      Description

      Streptococcal infections are caused by bacteria known as Streptococcus. There are several disease-causing strains of streptococci (groups A, B, C, D, and G), which are identified by their behavior, chemistry, and appearance. Each group causes specific types of infections and symptoms. These antibody tests are useful for group A streptococci. Group A streptococci are the most virulent species for humans and are the cause of strep throat, tonsillitis, wound and skin infections, blood infections (septicemia), scarlet fever, pneumonia, rheumatic fever, Sydenham's chorea (formerly called St. Vitus' dance), and glomerulonephritis.

      Although symptoms may suggest a streptococcal infection, the diagnosis must be confirmed by tests. The best procedure, and one that is used for an acute infection, is to take a sample from the infected area for culture, a means of growing bacteria artificially in the laboratory. However, cultures are useless about two to three weeks after initial infection, so the ASO, anti-DNase-B, and streptozyme tests are used to determine if a streptococcal infection is present.

      Antistreptolysin O titer (ASO)

      The ASO titer is used to demonstrate the body's reaction to an infection caused by group A beta-hemolytic streptococci. Group A streptococci produce the enzyme streptolysin O, which can destroy (lyse) red blood cells. Because streptolysin O is antigenic (contains a protein foreign to the body), the body reacts by producing antistreptolysin O (ASO), which is a neutralizing antibody. ASO appears in the blood serum one week to one month after the onset of a strep infection. A high titer (high levels of ASO) is not specific for any type of poststreptococcal disease, but it does indicate if a streptococcal infection is or has been present.

      Serial (several given in a row) ASO testing is often performed to determine the difference between an acute or convalescent blood sample. The diagnosis of a previous strep infection is confirmed when serial titers of ASO rise over a period of weeks, then fall slowly. ASO titers peak during the third week after the onset of acute symptoms of a streptococcal disease; at six months after onset, approximately 30% of patients exhibit abnormal titers.

      Antideoxyribonuclease-B titer (anti-DNase B, or ADB)

      Anti-DNase-B, or ADB, also detects antigens produced by group A strep, and is elevated in most patients with rheumatic fever and poststreptococcal glomerulonephritis. This test is often done concurrently with the ASO titer, and subsequent testing is usually performed to detect differences in the acute and convalescent blood samples. When ASO and ADB are performed concurrently, 95% of previous strep infections are detected. If both are repeatedly negative, the likelihood is that the patient's symptoms are not caused by a poststreptococcal disease.

      When evaluating patients with acute rheumatic fever, the American Heart Association recommends the ASO titer rather than ADB. Even though the ADB is more sensitive than ASO, its results are too variable. It also should be noted that, while ASO is the recommended test, when ASO and ADB are done together, the combination is better than either ASO or ADB alone.

      Streptozyme

      The streptozyme test is often used as a screening test for antibodies to the streptococcal antigens NADase, DNase, streptokinase, streptolysin O, and hyaluronidase. This test is most useful in evaluating suspected poststreptococcal disease following Streptococcus pyogenes infection, such as rheumatic fever.

      Streptozyme has certain advantages over ASO and ADB. It can detect several antibodies in a single assay, it is technically quick and easy, and it is unaffected by factors that can produce false-positives in the ASO test. The disadvantages are that, while it detects different antibodies, it does not determine which one has been detected, and it is not as sensitive in children as in adults. In fact, borderline antibody elevations, which could be significant in children, may not be detected at all. As with the ASO and ADB, a serially rising titer is more significant than a single determination.

      Preparation

      These tests are performed on blood specimens drawn from the patient's vein. The patient does not need to fast before these tests.

      Risks

      The risks associated with these tests are minimal, but may include slight bleeding from the blood-drawing site, fainting or feeling lightheaded after the blood is drawn, or blood accumulating under the puncture site (hematoma).

      Normal results

      Antistreptolysin O titer:


      adult: 160 Todd units/ml


      child: six months to two years: 50 Todd units/ml; two to four years: 160 Todd units/ml; five to 12 years: 170-330 Todd units/ml


      newborn: similar to the mother's value

      Antideoxyribonuclease-B titer:


      adult: 85 units


      child (preschool): 60 units


      child (school age): 170 units

      Streptozyme: less than 100 streptozyme units.

      Abnormal results

      Antistreptolysin O titer: Increased levels are seen after the second week of an untreated infection in acute streptococcal infection, and are also increased with acute rheumatic fever, acute glomerulonephritis (66% of patients will not have high ASO titers), and scarlet fever.

      Antideoxyribonuclease-B titer: Increased titers are seen in cases of acute rheumatic fever and poststreptococcal glomerulonephritis.

      Streptozyme: As this is a screening test for antibodies to streptococcal antigens, increased levels require more definitive tests to confirm diagnosis.

      Key Terms


      Antibody
      A protein manufactured by a type of white blood cells called lymphocytes, in response to the presence of an antigen, or foreign protein, in the body. Because bacteria, viruses, and other organisms commonly contain many antigens, antibodies are formed against these foreign proteins to neutralize or destroy the invaders.


      Antigen
      A substance that can trigger a defensive response in the body, resulting in production of an antibody as part of the body's defense against infection and disease. Many antigens are foreign proteins not found naturally in the body, and include bacteria, viruses, toxins, and tissues from another person used in organ transplantation.


      Glomerulonephritis
      An inflammation of the glomeruli, the filtering units of the kidney. Damage to these structures hampers removal of waste products, salt, and water from the bloodstream, which may cause serious complications. This disorder can be mild and cause no symptoms, or so severe enough to cause kidney failure.


      Rheumatic fever
      A disease that causes inflammation in various body tissues. Rare in most developed countries, but reported to be on the increase again in parts of the United States. Joint inflammation occurs, but more serious is the frequency with which the disease permanently damages the heart. The nervous system may also be affected, causing Sydenham's chorea.


      Sydenham's chorea
      A childhood disorder of the central nervous system. Once called St. Vitus' dance, the condition is characterized by involuntary, jerky movements that usually follow an attack of rheumatic fever. Rare in the United States today, but a common disorder in developing countries. Usually resolves in two to three months with no long-term adverse effects.
      For Your Information

      Resources

      Books



      Pagana, Kathleen Deska. Mosby's Manual of Diagnostic and Laboratory Tests. St. Louis: Mosby, Inc., 1998.






      Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group The Essay Author is Janis O. Flores.
      This article was updated on 08-14-2006

      تعليق


      • #4
        Definition


        Antistreptolysin O (ASO) titer is a blood test to measure antibodies against streptolysin O, a substance produced by Group A Streptococcus bacteria.

        Alternative Names
        ASO titer; ASLO
        Why the Test is Performed
        This test is used to detect prior infection by Group A Streptococcus, the bacteria responsible for diseases such as:

        Bacterial endocarditis
        Glomerulonephritis
        Rheumatic fever
        Scarlet fever
        Strep throat
        The ASO antibody may be found in the blood weeks or months after the strep infection has gone away.

        How the Test is Performed
        Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

        Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

        In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.

        The blood is then sent to the laboratory for analysis.

        How to Prepare for the Test
        You should not eat for 6 hours before the test.

        How the Test Will Feel
        When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

        Risks
        Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

        Other risks associated with having blood drawn are slight but may include:

        Excessive bleeding
        Fainting or feeling light-headed
        Hematoma (blood accumulating under the skin)
        Infection (a slight risk any time the skin is broken)
        Normal Results
        The ASO level is usually less than 160 Todd units per milliliter.

        Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

        What Abnormal Results Mean
        Abnormal results may be due to:

        Active streptococcal infection
        Bacterial endocarditis
        Post-streptococcal glomerulonephritis
        Rheumatic fever
        Scarlet fever

        تعليق


        • #5
          What are Mycoplasma and How Do They Work?

          Mycoplasma is the name given to a unique group of microorganisms that fall in the category between the bacteria and viruses. In fact, it is still debated whether the larger and more complicated bacteria evolved from the prehistoric mycoplasma (the smallest free-living organism) or whether they evolved from the viruses. The primary differences are that bacteria have a solid cell-wall structure (that is sensitive to penicillin) and they can be relatively easily grown in culture media. Mycoplasmas, on the other hand, do not have a cell wall and like the tiniest jellyfish with a pliable membrane, can take on many different shapes, making them difficult to identify even under a high powered electron microscope.

          Their accepted name was chosen because some strains were observed to have a mycelated fungi-like structure (as Mycology, the study of fungi) with a flowering plasma like structure, hence mycoplasma. The first strains were isolated in 1898 at the Pasteur Institute and for 60 years they were called pleuro-pneumonia-like organisms (PPLOs) having been isolated from cattle with arthritis and pleuro-pneumonia. The first human strain was isolated in 1932 from an abscess in a female patient. The first reported isolation of a mycoplasma from a rheumatoid patient was made in 1939 by Drs. Swift and Brown. Newer techniques have been able to identify many different strains that are essentially species specific; avian (chicken and turkeys), rodents (mice and rats), feline, canine, porcine, goats, sheep, elephants, etc. In particular, the non human primates (great apes) were found to be infected with the human mycoplasma strains, which made the arthritic gorillas the ideal animal model for the study of humans. Of particular support for the cause of rheumatoid arthritis are the many reports of mycoplasmas causing arthritis in most of all domestic animals, including the experimental laboratory mice and rat models. When tetracycline antibiotics became available in 1947, they, and not pencillins, were found to inhibit mycoplasma growth and also control animal arthritis.

          Mycoplasmas, unlike viruses, can grow in tissue fluids (blood, joint, heart, chest, and spinal fluids) and can grow in living tissue cell structures without killing the cells- as some viruses and bacteria do. Mycoplasmas are frequently isolated from the oral or genito-urinary tracts of normal population and are found to infect females four times more often than males, which just happens to be the same incident rate in rheumatoid arthritis and other related disorders. Mycoplasmas can attach to specific cells without killing the cells and thus their infection process can go undetected. No symptoms suggests no disease. In some people the attachment of mycoplasmas to the susceptible cell membranes acts like a living thorn, a persistent foreign substance, causing the host's immune defense mechanism to wage war. This allergic type of inflammation often results in heated, swollen, and painful inflamed tissues. In such cases the mycoplasma may not be isolated from the inflamed tissues but is detected by the host's serum antibody level. A positive response would indicate that mycoplasma has infected the host. A positive mycoplasma test would indicate further tetracycline or anti-mycoplasma treatment.

          Mycoplasma growth is also suppressed by gold salts, some antimalarial drugs and even bee venom - all are which are more toxic and less effective than tetracyclines.

          Unfortunately, mycoplasmas never became part of medical school curriculum or textbooks until the late 50s and were considered as some oddity until one strain (mycoplasma pneumoniae) was identified as the cause of atypical pneumonia. This strain of mycoplasma as well as others have been suggested as a contributing factor for rheumatic disease. These diseases may be considered to be the results of immune complex (mycoplasma + antibody) and also the self destructive autoimmune reaction (mycoplasma + host protein ). Recent studies are now supporting the role and mechanism of mycoplasmas as both immune complex and as an autoantigen. If this proves to be the case, we may soon see mycoplasma associated with many other immunological disorders besides rheumatoid, i.e. diabetes, multiple sclerosis, etc.

          Mycoplasma Complement Fixation Test

          This test, mycoplasma complement fixation or MCF, identifies antibodies to a specific mycoplasma and are reported as a titer to the specific mycoplasma (s) resident in the patient. This is more specific than the m. pneumoniae kit.

          PCR (Polymerase Chain Reaction) Test

          This test identifies the mycoplasma strain by its DNA or genetic makeup. Results are + or -.

          For Dr. Thomas McPherson Browns view of mycoplasma, read The New Arthritis Breakthrough, by Henry Scammell published by M. Evans, New York

          -Portions of the above were excerpted from an article by Harold W. Clark-

          How are the results interpreted?

          With the MCF, low titers are significant. Sometimes disease activity is not sufficient to produce a measurable level of antibody to mycoplasma. In this case, when antibiotics are administered, the subsequent attack on the organism generates a higher level of antibodies which than can be measured. An early test which was negative may become positive after a period of antibiotic treatment

          PCR testing is by individual strain and is either positive or negative. It is very sensitive.

          Where can I have mycoplasma test done?

          Mycoplasma testing is very specialized; not every lab does this testing or does it well. Ask other patients on the Road Back Foundation Bulletin Board for resources which will help you to find the appropriate testing.


          --------------------------------------------------------------------------------

          The Road Back Foundation does not engage in the practice of medicine. Consult with a physician to assess any medical treatment that is being considered. The Road Back Foundation encourages healthcare consumers to thoroughly investigate and understand all treatments and medications before proceeding. This material is for educational purposes only

          The Road Back Foundation
          P.O. Box 410184
          Cambridge, MA 02141
          614-227-1556
          www.roadback.org






          The Road Back Foundation: Educational Use Permitted

          تعليق


          • #6
            :sm186::sm199::sm189:

            تعليق


            • #7
              مشكوررررررررررررررررررررررررررررر
              [COLOR="purple"]سبحان الله وبحمده[/COLOR]

              تعليق


              • #8
                شكرا جزيلا للعضو الجديد m.noorعلى موضوع ASO.mycoplasma

                تعليق


                • #9
                  شكرا لكي عزيزتي على موضوعك الرائع
                  تحياتي لك:sm180::sm199::sm189::sm188:
                  :extra59: العلم نور :extra57:

                  تعليق

                  يعمل...
                  X