Iron absorption and its regulation. A review.
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Absorption↗
Biomedical subjects
J J Marx
Publications and source records attributed to J J Marx.
Normal iron absorption and decreased red cell iron uptake in the aged.
Absorption of iron was studied with a double-isotope technique that allowed differentiation between "mucosal uptake," "mucosal transfer," and ultimate "retention" of iron. A physiologic dose of ferrous sulfate was administered to 25 healthy young adults, 40 active aged persons, and 20 patients with uncomplicated iron deficiency. Radioactivity was measured with a whole-body scanner. Iron absorption values were not decreased in aged subjects compared to young adults. Mucosal uptake, mucosal transfer, and retention of iron were equally increased in both young and old patients with iron deficiency. In 12 young adults and 33 aged persons red cell iron uptake was studied in addition to iron absorption. Young adults utilized 91% of the retained, orally administered iron and the aged only 66%. An increase in ineffective erythropoiesis in old age is suggested.
Absorption↗
Farmer's lung disease among farmers with precipitating antibodies to the thermophilic actinomycetes: a clinical and immunologic study.
Farmers were evaluated for the presence of farmer's lung disease by serologic methods and by clinical histories. From a large farming population screened serologically, 40 of 92 farmers with precipitating antibodies to the thermophilic actinomycetes consented to be evaluated for clinical evidence of farmer's lung disease. Each subject completed a standardized questionnaire which was reviewd by a trained observer. On the basis of the questionnaire and an indepth clinical history, the subjects were grouped into those farmers who had a history of farmer's lung disease (38%), those with no history (50%), or a doubtful group (12%). When these groups were compared for radiologic changes, pulmonary function abnormalities, and immune function, no differences were discernible. None of the parameters tested were useful in predicting which farmer would develop clinical farmer's lung disease. The parameters tested did not provide reliable criteria for differentiating those patients who present without acute symptoms but relate a history of recurrent pulmonary illnesses associated with moldy forage.
Actinomycetales↗
Immunological studies on an aberrant form of ataxia telangiectasia.
We describe two brothers with ataxia telangiectasia (AT) of which one was unique in that he had no detectable IgG and IgA concentrations in the serum or saliva. The other brother had the more common IgA deficiency in the serum and saliva. Neither patient had a history of undue sinopulmonary infections. In spite of the absence of these immunoglobulins in the sera, there were cells in the bone marrow and peripheral blood that stained with fluorescein-labeled anti-IgG and anit-IgA. Both patients had demonstrable humoral antibody and cell-mediated immune responses to the antigens tested. We also discuss possible pathophysiological mechanisms causing the above defects.
Adult↗
Activation of the complement cascade by a purified component of pigeon dropping extract (PDE1).
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Animals↗
Correlation of exposure to various respiratory pathogens with farmer's lung disease.
Complement-fixing antibodies (CFA) to a panel of microorganisms commonly associated with respiratory disease were measured in a number of agricultural populations. The panel included Mycoplasma pneumoniae, influenza viruses A and B, parainfluenza virus types 1, 2, and 3, adenovirus, and respiratory syncytial virus. The agricultural populations were grouped according to a clinical history of farmer's lung disease (FLD) and the presence of antibodies to the thermophilic actinomycetes (TA). Farmers with precipitating antibody activity to one or more of the TA (groups I and II) demonstrated a greater frequency of CFA to M. pneumoniae and parainfluenza virus types 1, 2, and 3 than those groups without antibody to the TA, but the level of CFA was not higher in the positive subjects. Immunoglobulin levels were also elevated in groups I and II when compared to the control groups. Unlike IgG and IgM, IgA was elevated only in the farmers who had a clinical history of FLD (group I) but not in farmers without a clinical history. The results suggest that farmers who develop FLD are exposed to a wider variety of pathogens than are other farmers, but do not respond in an accelerated manner.
Actinomycetales↗
Comparative electrophoresis of the proteins and proteases in thermophilic actinomycetes.
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Actinomyces↗
Activation of the complement sequence by extracts of bacteria and fungi associated with hypersensitivity pneumonitis.
Complement (C) consumption by antigens associated with hypersensitivity pneumonitis was investigated. Micropolyspora faeni in the presence of precipitating antibodies consumed C in a manner similar to the BSA-anti BSA system. An extract of M. faeni was shown to consume C and convert C3PA to C3A in the absence of detectable antibodies. In addition, three species of Aspergillus and two strains of Thermoactinomyces vulgaris were also shown to have the same activity with respect to C3PA. Mucor racemosus, Hormodendrum sp. and a mixed extract of Penicillium did not convert C3PA.
Animals↗
Complement fixation test as an aid in the diagnosis of farmer's lung.
Complement-fixing antibodies to Micropolyspora faeni were measured in farmers and controls. Farmers with known or suspected farmer's lung showed significantly higher titers than control groups. Variations in titer were measured and correlated with the clinical disease.
Antibodies, Bacterial↗
Delayed hypersensitivity to beryllium compounds.
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Animals↗
A study of the afferent and efferent limbs of the immune response in opossums.
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Age Factors↗
The amount of ferritin and hemosiderin in the livers of patients with iron-loading diseases.
Depot iron, ferritin iron, and ferritin protein were measured in 34 liver needle biopsy specimens obtained from patients with primary and secondary iron-loading diseases. The patients were classified as idiopathic hemochromatosis (14), porphyria cutanea tarda (4), and iron-loading anemias (16). With accumulation of depot iron, the amount of liver ferritin protein increased, however, the ratio of ferritin protein to depot iron fell at concentrations of depot iron in excess of 1,000 micrograms per gm of liver. The liver ferritin protein concentration was not influenced by the specific kind of the iron storage disorder. The mean iron content of ferritin molecules increased about 50% in profound iron overload. In low grade iron overload, the bulk of depot iron was present as ferritin; however, in subjects with heavy iron overload, depot iron consisted of approximately equal amounts of hemosiderin (nonferritin iron) and ferritin iron.
Anemia↗
Ultrastructural evidence for the presence of ferritin-iron in the biliary system of patients with iron overload.
Ferritin-like particles were observed in bile canaliculi of patients with iron overload. These particles have been further investigated by: a staining method enhancing the size and contrast of ferritin protein, and electron probe microanalysis detecting the presence of the elements iron and phosphorus. Morphological observation of coated vesicles in the cytoplasm adjacent to the bile canaliculi and coated pits in the canalicular membrane suggests a transport mechanism via membrane-bound organelles. Support is given to the theory that part of the iron, stored in the liver, leaves the hepatocyte by excretion of ferritin into the bile.
Anemia, Sideroblastic↗
Determination of iron to phosphorus ratios of iron storage compounds in patients with iron overload: a chemical and electron probe X-ray microanalysis.
The amounts of phosphorus and iron in various isolated ferritin preparations were investigated by: chemical analysis on ferritin samples and electron probe X-ray microanalysis on ferritin particles from the same preparations. A high correlation was found between iron to phosphorus ratios obtained by both methods. Further investigation by electron probe X-ray microanalysis on lysosomes of hepatic cells of patients with idiopathic and secondary hemochromatosis revealed lysosomal iron to phosphorus ratios which were very similar in all parenchymal cells but different from ratios obtained in Kupffer cells. Lysosomal iron to phosphorus ratios in hepatocytes did not change after intensive phlebotomy treatment. It is postulated therefore that, during phlebotomy, iron and phosphorus are concomitantly lost from the hepatic lysosomes.
Bloodletting↗
Local versus regional procurement and distribution of granulocytes.
Granulocyte concentrates obtained by discontinuous flow centrifugation (DFC) and continuous flow centrifugation (CFC) were studied. The DFC granulocytes were obtained from a regional center and stored for 24 hours prior to transfusion. The CFC granulocytes were obtained locally and transfused within a few hours. Even at 24 hours, DFC granulocytes had significantly reduced bactericidal capacity, chemiluminescence, nitroblue tetrazolium reduction, chemotaxis and random mobility. Granulocyte kinetics utilizing DF32P and skin windows demonstrated the ability of DFC granulocytes to circulate and migrate into the tissues despite the in vitro abnormalities. Until effective storage techniques for granulocyte preservation became available, rapid transportation and processing from regional centers or local procurement of granulocytes is necessary to transfuse functional granulocytes.
Blood Bactericidal Activity↗
Iron content and acid phosphatase activity in hepatic parenchymal lysosomes of patients with hemochromatosis before and after phlebotomy treatment.
Lysosomal structures in liver parenchymal cells of 3 patients with iron overload and of 3 subjects without iron-storage disorders were investigated. A combination of enzyme cytochemistry--with cerium as a captive ion to demonstrate lysosomal acid phosphatase activity--and electron probe X-ray microanalysis (EPMA) was used. We were able (1) to define and quantify lysosomal structures as lysosomes, siderosomes, or residual bodies, (2) to quantify the amount of iron and cerium simultaneously in these structures, and (3) to evaluate a possible relation between iron storage and enzyme activity. With histopathologically increased iron storage, the number of siderosomes had increased at the cost of lysosomes, with a corresponding increase in acid phosphatase activity in both organelles. In histopahtologically severe iron overload, however, acid phosphatase activity was low or not detectable and most of the iron was stored in residual bodies. After phlebotomy treatment, the number of siderosomes had decreased in favor of the lysosomes, approaching values obtained in control subjects, and acid phosphatase activity was present in all iron-containing structures. In this way a relationship between iron storage and enzyme activity was established. The iron content of the individual lysosomal structures per unit area had increased with histopathologically increased iron storage and had decreased after phlebotomy treatment. From this observation, it is concluded that the iron status of the patient is not only reflected by the amount of iron-containing hepatocytes but, as well, by the iron content lysosomal unit area.
Acid Phosphatase↗
Protoporphyrin photosensitivity cannot be attenuated by oral N-acetylcysteine.
The photodermatosis in erythropoietic protoporphyria (EPP) is caused by the accumulation of photosensitizing protoporphyrin (PP) in the skin, due to a defect in ferrochelatase, the enzyme that inserts ferrous iron into PP to form heme. Hydroxyl radical (.OH) and singlet oxygen generation with subsequent lipid peroxidation are thought to play a major role in the pathogenesis of the photodermatosis in EPP. Hydrogen peroxide (H2O2) can generate .OH in the Haber-Weiss as well as the Fenton reaction, and is thus a potentially harmful intermediate in the photoreduction of O2. The use of oxyradical scavengers, such as beta-carotene, has been reported to be beneficial in the treatment of EPP photodermatosis. In this study, N-acetylcysteine (NAC) 1800 mg/day was used for 3 reasons: (i) its -SH groups directly scavenge H2O2; (ii) ferrochelatase can be activated by sulfhydryl groups; (iii) NAC was reported to upregulate the glutathione redox system, which is a major endogenous anti-oxidant system. However, in a double-blind crossover placebo controlled study on 6 EPP patients, we could neither demonstrate an effect through photosensitivity tests, nor on light hypersensitivity as reported by the patients. This dosage of NAC could not increase reduced glutathione and did not affect the red blood cell PP content nor the excretion of PP in the feces. Neither were adverse effects observed. We conclude that the oral administration of NAC, in the relatively low dose used here, is not effective in the treatment of photodermatosis in EPP.
Acetylcysteine↗