Most acute phase proteins are synthesized in the liver, although the genes for some are also expressed in cells and tissues elsewhere. Transcriptional control is the main mechanism for regulation of production hut mRNA stability contributes in some cases. A large number of cytokines, including interleukin I (IL-1), IL-6, tumours necrosis factor a and various interferons, are capable of inducing increased, or in some cases decreased, production of various acute phase proteins in vivo and in cultured hepatocytes and liver ccli Lines in vitro. Glucocorticoids and steroid sex hormones can play an important permissive role and neural and neuroendocrine influences may be significant in vivo. Results obtained in different laboratories with different acute phase proteins, different cytokines and different cell lines or experimental systems have shown much variation.
It has been difficult to reconcile all the findings and to identify the critical participation of particular mediators in control of particular reactants, especially because of the cascade effects by which some cytokines promote the production of others. Nevertheless it is striking that 11-6 knockout mice mount absolutely no acute phase response of serum amyloid A protein (SAA), serum amyloid P component (SAP) or complement component C3 following induction of sterile inflammation by casein or silver nitrate injection, whereas lipopolysaccharide (I .PS induces a definite, although subnormal, response.
Studies with transgenic mice bearing the human CRP gene, with transfected cells containing human SAA genes, and with hepatoma cell lines, have identified regulatory flanking regions of DNA which are targets for the action of nuclear Factors responsive to IL-6 and IL-I.
While the profile of acute phase plasma proteins is broadly similar across species there are nonetheless important differences. For example, SAP is a major acute phase reactant only in the mouse, and there are many other differences in normal levels and acute phase behaviour of other members of the pentraxin family of proteins to which it belongs. While these differences may be important for the usefulness of particular proteins as markers in clinical or experimental situations, they may not reflect, as has been pointed out above, the underlying metabolic regulation. On the other hand, some species differences are clearly of physiological and pathophysiological importance. Thus, although rats have a gene for a homolog of SAA, the expression of which is regulated as an acute phase protein, the product does not appear as a plasma lipoprotein and rats never get AA amyloidosis. This contrasts with the behaviour of SAA in all other mammals and birds which have been studied.
Asthma is a complex syndrome rather than a single disease entity. Different phenotypes with varying prognosis and determinants have been described, particularly over childhood years 2 and will be discussed in detail in the following. For example, transient early wheezing is characterized by the occurrence of wheezing in infants up to the age of 2 to 3 years which disappears thereafter. The main predictor of these wheezing illnesses is premorbid reduced lung function before the manifestation of any wheeze. These decrements in pulmonary function are in part determined by passive smoke exposure in utero 4 and result in symptoms of airway obstruction when infants get infected with respiratory viruses. (more…)
Definitions of anaphylaxis vary considerably, impeding the comparison of different clinical studies. Different definitions of anaphylaxis have been developed as clinical descriptions of severe allergic reactions, different authors emphasizing different symptoms.
The author aimed to develop a simple clinical grading system and definition for anaphylaxis using clinical data. He retrospectively analyzed 1149 case records (median age 29 years) with systemic allergic reactions (30% venom allergy, 22% iatrogenic allergy, 18% food allergy) from an emergency department in Australia. (more…)
Cow’s milk allergy results when antibodies against milk allergens are produced by the immune system.
Milk allergens are proteins; more than 25 distinct milk proteins have been identified in the various fractions of milk. The fractions include casein, whey, serum, and certain additional ingredients. (more…)
A better detection, the least restrictive health food allergies choices, specific measures of allergy prevention, and teaching guidelines on potential new therapies has known to improve the management of food allergies. This new approaches give hope to more than twelve million Americans who are affected by food allergy. (more…)
It is clear from the results of large epidemiologic studies that while atopy is a major risk factor for asthma, it is usually not sufficient by itself to drive the disease process to chronicity, as less than 25% of atopics develop persistent asthma. The situation in childhood is further complicated by an additional series of development factors, related to postnatal maturation of respiratory function. (more…)
A preliminary study conducted in New Zealand shows that a natural chemical compound blackcurrants can help breathe allergic asthma sufferers. It was known that fruit consumption may reduce symptoms of allergic asthma, but this study is the first to demonstrate how this phenomenon occurs. (more…)
Nerve fibers containing a variety of neuropeptides, including substance P and CGRP, have been demonstrated in human skin. Intradermal injection of substance P results in an immediate wheal-and-flare reaction , whereas the main effect of CGRP is a long-lasting (4–6 hours) intense erythema. Additionally, CGRP potentiates edema formation evoked by mediators such as substance P. (more…)
