Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Myeloperoxidase, deficiency

Myeloperoxidase is an extremely potent, antimicrobial protein that is present in neutrophils at up to 5% of the total cell protein. Its role in the killing of a wide range of bacteria, fungi, viruses, protozoa and mammalian cells (e.g. tumour cells) is well established from in vitro studies. It also plays an important role in the inactivation of toxins and the activation of latent proteases, as well as in other functions described in section 5.4.1. In view of this apparent central role in neutrophil function during host defence, one would think that any deficiencies in this enzyme would have disastrous consequences on the ability of the host to combat infections. Until the early 1980s, this key role for myeloperoxidase in host protection seemed substantiated by the extremely low incidence of reports of patients with deficiencies of this enzyme. Indeed, up to this time, only 15 cases from 12 families had been reported worldwide. Sometimes these patients were asymptomatic but often suffered Candida infections, particularly if their myeloperoxidase deficiency was also associated with diabetes mellitus. [Pg.272]

It was therefore somewhat surprising when, in the early 1980s, a number of independent reports worldwide indicated that myeloperoxidase deficiencies may be quite common in the population of apparently-healthy individuals. These observations came from the use of the Hemalog D or Technicon H6000, flow-cytochemical systems intended to automate differential white blood counts. Part of this system uses a peroxidase stain, and hence neutro- [Pg.272]

It was also discovered that myeloperoxidase is not present in the neutrophils of chickens, but this deficiency is not normally associated with an increased prevalence of infections. Thus, if many healthy individuals (or chicken neutrophils) possess low or zero levels of myeloperoxidase but have no increased risk of infection, what really is the importance of the myeloperoxidase system in neutrophil function during host protection  [Pg.273]

in vitro evidence suggests that if myeloperoxidase is completely absent from neutrophils (or else its activity is inhibited), then certain bacteria (e.g. S. aureus) are killed more slowly, whereas others (e.g. Candida) [Pg.274]

These myeloperoxidase deficiencies may be hereditary or acquired. The genetics of hereditary myeloperoxidase deficiency are unknown, but a survey of patients by Nauseef and co-workers (Nauseef 1988) revealed (by im-munoblotting) that, in many patients, the mature enzyme was absent but promyeloperoxidase was present. Such observations suggest that in these patients the gene is normal and may be normally transcribed the defect resides in how this protein is processed and perhaps packaged. [Pg.276]


Brennan M-L and et al. (2002) A tale of two controversies. Defining both the role of peroxidases in nitrotyro-sine formation in vivo using eosinophil peroxidase and myeloperoxidase-deficient mice, and the natnre of the peroxidase-generated reactive nitrogen species. J Biol Chem 277 17415-17427. [Pg.517]

Nauseef, W. M. (1986). Myeloperoxidase biosynthesis by a human promyelocytic leukemia cell line Insight into myeloperoxidase deficiency. Blood 67,865-72. [Pg.75]

Additionally, the myeloperoxidase system even regulates the duration of the respiratory burst because neutrophils from patients with myeloperoxidase deficiency (see 8.3) generate more reactive oxidants than control cells. Also, when myeloperoxidase is inhibited with a specific antibody or a specific inhibitor such as salicylhydroxamic acid, the duration of the respiratory burst, but not the maximal rate of oxidant production, is extended. This indicates that a product of the myeloperoxidase system inhibits the NADPH oxidase and so self-regulates reactive oxidant production during inflammation. [Pg.171]

Figure 8.2. Killing of Staphylococcus aureus by normal and myeloperoxidase-deficient neutrophils. Kinetics of killing of opsonised S. aureus by normal ( ) and myeloperoxidase-deficient neutrophils (O). Figure 8.2. Killing of Staphylococcus aureus by normal and myeloperoxidase-deficient neutrophils. Kinetics of killing of opsonised S. aureus by normal ( ) and myeloperoxidase-deficient neutrophils (O).
A study of 148000 subjects by Lanza and colleagues (1987) reported 36 individuals with myeloperoxidase deficiency, 10 of whom were completely deficient a further 2 individuals with total deficiency were identified from familial studies. Of the 12 patients with total deficiency, 7 had either benign or malignant tumours, but none was undergoing radio- or chemotherapy at the time of analysis hence, the myeloperoxidase deficiency could not be attributed, in these cases, to the therapy used for treatment of the malignant disease. These findings imply either that the tumour somehow affects the expression of myeloperoxidase in these patients, or that myeloperoxidase-deficient individuals perhaps have an increased incidence of tumours. Much follow-up work is needed for these studies on myeloperoxidase-deficient neutrophils in order to evaluate these proposals. [Pg.276]

Breton-Gorius, J., Houssay, D., Dreyfus, B. (1975). Partial myeloperoxidase deficiency in a case of preleukaemia. Brit. J. Haematol. 30,273-8. [Pg.286]

Lanza, F., Fietta, A., Spisani, S., Castoldi, G. L., Traniello, S. (1987). Does a relationship exist between neutrophil myeloperoxidase deficiency and the occurrence of neoplasms J. Clin. Lab. Immunol. 22,175-80. [Pg.287]

Lehrer, R. I., Cline, M. J. (1969). Leukocyte myeloperoxidase deficiency and disseminated candidiasis The role of myeloperoxidase in resistance to Candida infection. J. Clin. Invest. 48,1478-87. [Pg.287]

Nauseef, W. M. (1988). Myeloperoxidase deficiency. In Phagocytic Defects, vol. I (Hematology/Oncology Clinics of North America), pp. 135-58, W. B. Saunders, Philadelphia. [Pg.288]

Brennan M-L, Anderson MM, Shih DM, Qu X-D, Wang X, Mehta AC, Lim LL, Shi W, Hazen SL, Jacob JS, Crowley JR, Heinecke JW, Lusis AJ (2001) Increased Atherosclerosis in Myeloperoxidase-Deficient Mice. J Clin Invest 107 419... [Pg.464]

Zhang R, Shen Z, Nauseef WM, Hazen SL. 2002b Defects in leukocyte-mediated initiation of lipid peroxidation in plasma as studied in myeloperoxidase-deficient subjects Systematic identification of multiple endogenous diffusible substrates for myeloperoxidase in plasma. Blood 99 1802-810. [Pg.158]

In the inherited syndrome of chronic granulomatous disease (CGD), cytochrome Z 245 is absent and consequently the respiratory burst cannot take place [6], Persistent, but selective, bacterial infections are seen in these patients. NADPH oxidase is useful as part of a controlled acute inflammatory response to bacterial invasion, but excessive activity of this enzyme might lead to tissue destruction. In addition to PMN s, other inflammatory cell types, e.g. lymphocytes and macrophages, possess a membrane NADPH oxidase [7], ROI production by these latter cell types may form part of an intercellular communication pathway important in the inflammatory response [8], and perhaps an absence of this cell signalling route in CGD patients is linked to the development of chronic granulomata in these patients. Interestingly, myeloperoxidase deficiency is not associated with disease. [Pg.362]

The relative importance of the contribution of superoxide/hydrogen peroxide and hypochlorous acid in the bacterial killing mechanism is seen in patients with chronic granulomatous disease (CGD, with a defective NADPH-oxidase system), and those that are myeloperoxidase-deficient. CGD patients show persistent multiple infections especially in the skin, lungs, liver and bones by those bacterial strains whose killing by neutrophils requires oxygen. Individuals who are deficient in myeloperoxidase show no symptoms. [Pg.31]

R9. Rosen, H., and Klebanoff, S. J, Chemiluminescence and superoxide production by myeloperoxidase-deficient leukocytes. J. Clin. Invest. 58, 50-60 (1976). [Pg.154]

Kutter, D., P. Devaquet, G. Vanderstocken, J. M. Paulus, V. Marchal, and A. Gothot. 2000. Consequences of total and subtotal myeloperoxidase deficiency Risk or benefit QgemMo 104(l) 10-5. [Pg.96]

Brennan ML, Anderson MM, Shih DM, et al. Increased atherosclerosis in myeloperoxidase-deficient mice. / Clin Invest 2001 107 419-430. [Pg.172]

In certain disorders, there is complete loss of either enzymatic activity or nonenzymatic protein function. In these disorders, the homozygote lacks enzymatic and antigenic activity. These conditions have been considered to be due to silent genes." Disorders that may be considered in this category include myeloperoxidase deficiency... [Pg.635]


See other pages where Myeloperoxidase, deficiency is mentioned: [Pg.63]    [Pg.272]    [Pg.273]    [Pg.273]    [Pg.274]    [Pg.274]    [Pg.275]    [Pg.275]    [Pg.276]    [Pg.287]    [Pg.288]    [Pg.288]    [Pg.252]    [Pg.264]    [Pg.264]    [Pg.55]    [Pg.55]    [Pg.148]    [Pg.77]    [Pg.354]    [Pg.160]    [Pg.160]    [Pg.19]    [Pg.268]    [Pg.93]    [Pg.315]    [Pg.24]   
See also in sourсe #XX -- [ Pg.171 ]

See also in sourсe #XX -- [ Pg.252 ]




SEARCH



Myeloperoxidase

© 2024 chempedia.info