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Biomedical subjects

E D Weinberg

Publications and source records attributed to E D Weinberg.

At least 19 recordsLinked to original sources

Iron loading: a risk factor for osteoporosis.

Iron loaded persons are at increased risk for infection, neoplasia, arthropathy, cardiomyopathy and an array of endocrine and neurodegenerative diseases. This report summarizes evidence of increased risk of iron loading for osteoporosis. Iron suppresses bone remodeling apparently by decreasing osteoblast formation and new bone synthesis. Low molecular mass iron chelators as well as a natural protein iron chelator, lactoferrin, may be useful in prevention of osteoporosis.

Adult↗

Suppression of bacterial biofilm formation by iron limitation.

The concentration of iron that permits bacterial differentiation generally differs from that needed for vegetative cell growth. An undesirable manifestation of differentiation is biofilm formation. The process in some, but not all, bacterial systems requires a higher level of iron than is needed for growth and it is suppressed by specific iron chelators. Human transferrin and lactoferrin, as well as at least six low molecular mass iron chelators, are now available for possible screening and clinical development as inhibitors of bacterial biofilm formation.

Bacterial Adhesion↗

Do some carriers of hemochromatosis gene mutations have higher than normal rates of disease and death?

Some heterozygote carriers of hemochromatosis HFE gene mutations become iron loaded with ensuing increased risk of disease and premature death. Contributing nutritional, behavioral and genetic factors are beginning to be identified. Carriers of HFE gene mutations should be advised to minimize contributing factors, if possible, and to have their iron values tested periodically. If values begin to rise, a schedule of phlebotomies should be considered.

Hemochromatosis↗

Iron loading: a risk factor for Whipple's disease?

Because of impairment of microbial iron acquisition ability, some potential pathogens can cause disease only in iron loaded hosts. Tropheryma whippelii, the etiologic agent of Whipple's disease, is a possible example. Whipple's disease is non-contagious, occurs mainly in middle-aged white males, and displays many, but not all, of the complications of hereditary haemochromatosis. Tropheryma whippelii is a gastrointestinal commensal that causes disease in persons who have a Th1-Th2 imbalance. Host susceptibility may be exacerbated by iron loading. Consideration should be given to have patients evaluated for levels of interferon-gamma and interleukin-4 as well as for serum ferritin and transferrin iron saturation.

Adolescent↗

Iron, infection and sudden infant death.

Three risk factors for sudden infant death syndrome are well established: maternal smoking, prone sleeping position and non-breast feeding. Two additional risk factors have been proposed: microbial infection in the gastrointestinal or respiratory tracts and iron loading. This review endeavors to integrate these five disparate factors into a unifying concept.

Bacterial Infections↗

Human lactoferrin: a novel therapeutic with broad spectrum potential.

Lactoferrin (Lf), a natural defence iron-binding protein, has been found to possess antibacterial, antimycotic, antiviral, antineoplastic and anti-inflammatory activity. The protein is present in exocrine secretions that are commonly exposed to normal flora: milk, tears, nasal exudate, saliva, bronchial mucus, gastrointestinal fluids, cervico-vaginal mucus and seminal fluid. Additionally, Lf is a major constituent of the secondary specific granules of circulating polymorphonuclear neutrophils (PMNs). The apoprotein is released on degranulation of the PMNs in septic areas. A principal function of Lf is that of scavenging free iron in fluids and inflamed areas so as to suppress free radical-mediated damage and decrease the availability of the metal to invading microbial and neoplastic cells. Mechanisms of action of Lf in addition to iron deprivation are also described. Administration of exogenous human or bovine Lf to hosts with various infected or inflamed sites has resulted in some prophylactic or therapeutic effects. However, an adverse response to the protein might occur if it were to stimulate antibody production or if it were to provide iron to the invading pathogen. The recombinant form of human Lf has become available and development of the product for use in a wide range of medical conditions can now be anticipated.

Animals↗

Modulation of intramacrophage iron metabolism during microbial cell invasion.

The mechanisms whereby vertebrate hosts withhold iron from microbial invaders, as well as the methods used in attempts by invaders to capture the growth-essential metal, differ between host extracellular and intracellular environments. This review focuses on procedures employed by host cells and by invaders, respectively, that alter intramacrophage iron metabolism.

Animals↗

Microbial pathogens with impaired ability to acquire host iron.

Successful microbial pathogens must be adept in obtaining growth-essential iron from healthy hosts. Some potential pathogens, however, are sufficiently impaired in iron acquisition ability so as to be dangerous mainly in hosts with such iron loading conditions as alcoholism, asplenia, hemochromatosis, beta-thalassemia major, or tobacco smoking. The association of six impaired pathogens (Capnocytophaga canimorsis, Yersinia enterocolitica and Y. pseudotuberculosis, Vibrio vulnificus, Tropheryma whippelii, and Legionella pneumophila) with iron loaded humans is described.

Actinomycetales↗

Iron therapy and cancer.

Anemia in cancer patients has many etiologies. Iron therapy clearly is indicated in patients whose anemias are associated with iron deficiency. However, a frequent cause of anemia in cancer is the "anemia of chronic disorders," in which, although functional iron may be low, tissue iron remains normal or high. Administration of iron with erythropoietin to such patients requires careful and frequent evaluation of hematologic and iron values. Inadvertent iron loading can contribute to deterioration of a variety of organ systems, as well as to increased proliferation of neoplastic cells.

Anemia↗

The development of awareness of the carcinogenic hazard of inhaled iron.

Numerous studies have observed that workers in ferriferous industries have an elevated risk of respiratory tract neoplasia. Research at the cellular and animal model levels indicates that iron compounds, per se, are carcinogenic. However, some investigators have suggested that inhaled iron compounds are merely carriers of other carcinogens. Evidence is presented that iron apparently is a principal carcinogenic hazard in inhalation of silicon dioxide, asbestos, and tobacco smoke. Included in the discussion are unresolved questions concerning the precise role of inhaled iron as a carcinogen.

Animals↗