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Biomedical subjects

A M Ganzoni

Publications and source records attributed to A M Ganzoni.

At least 19 recordsLinked to original sources
PubMed1980

Critical examination for the presence of a low molecular weight fraction in serum iron.

Native human pool serum and individual sera were ultrafiltered by Pellicon ultrafilters (Millipore) and the ultrafiltrates were extracted by an ammonium pyrrolidinedithiocarbamate/methylisobutylketone system after addition of different internal iron standards to three of four identical ultrafiltrates. The extracts were examined for iron content by atomic absorption spectrometry. During ultrafiltration pH 7.4 was maintained by a constant atmosphere of a CO2/air mixture. Low molecular weight iron in native human sera from normal, normal orally iron substituted and siderotic individuals was found to be less than 0.05 micrograms/100 ml. Elevating serum citrate to 3-fold normal had no effect on this result. More iron became ultrafiltrable if the serum pH were lowered by citric acid as compared with hydrochloric acid.

Citrates↗
PubMed1978

[Iron deficiency in infection].

As a rule bacterial infection is followed by acute serum iron reduction; impaired inflow of iron from storage sites into the transport pool represents the main cause. As a consequence of this sort of iron redistribution iron becomes short for red cell production; this is one cause for the development of anemia. The biological significance of hyposideremia may be presumed from the bacteriostatic potential of iron free transferrin, preventing adequate iron acquisition by multiplying microorganisms. Preliminary animal experiments support this concept and suggest that it might also be applied to true iron deficiency.

Anemia, Hypochromic↗
PubMed1978

[Microaggregates in stored blood: comparative evaluation of whole blood and buffycoat-free red cell concentrates (author's transl)].

Routine preparation of red cell concentrates in our institute removes 90% of platelets and 70% of leucocytes in whole blood. Microaggregate formation in whole blood and red cell concentrates was comparatively evaluated by blood passage through a membrane filter with a pore size of 12 micron. Dry weight residues on the filter due to microaggregates were 5 to 10 times lower in red cell concentrates as compared to whole blood at any point of a 20 day storage period. In addition, the decrease in flow rate with increasing storage time was much more marked for whole blood than for red cell concentrates.

Adult↗
PubMed1977

[Iron overload: effect on specific and nonspecific immunity].

Acute overload with an iron salt in mice enhanced the virulence of a relatively avirulent type of Salmonella typhimurium in a dose-dependent fashion. Iron administration also partly abolished specific immunity. Ferritin iron did not display the virulence-enhancing effect.

Animals↗
PubMed1976

Editorial: Red cell ageing and death.

To obtain red cell populations of increasing mean age erythropoiesis was arrested through continuous actinomycin treatment or maintained transfusion polycythemia in mice and rats respectively. The parameters studied included cell indices, enzyme activities and rheological characteristics. Further, the life-span of aged cells was compared to normal, and the sequestration site was determined. Mice erythrocytes, like those of rats, exerienced a continuous decrease in MCV1, an early rise in MCHC, and late MCH reduction. In ageing rat erythrocytes the activities of HK, GR and 6-PGD did not fall below the normal range during the first 9 tenths of the potential life-span. On the other hand, a borderline reduction of PK activity was found, and the activity of G-6PD underwent a steady though unimpressive decrease to 70% of the physiological average. Aged erythrocytes, forced through 15-mum capillaries differed in apparent viscosity from reticulocytes and normal cells by a factor of 1.31 and 1.16, respectively. Destruction of senescent cells was predominantly confined to the spleen, and prolonged erythrocyte survival followed splenectomy.

Animals↗
PubMed1975

[Disorders of hemoglobin synthesis (exclusive of iron deficiency)].

Hemoglobinopathies in the strict sense most often involve single amino acid substitutions. The clinical consequences, if any, are anemia, erythrocytosis and met-hemoglobinemia. In the thalassemias, which are characterized by microcytosis, unbalanced synthesis of normal globin chains exists and disease severity is primarily determined by the amount of relative overproduction of the unaffected chain: thus, the unstable chain tetramers precipitate and lead to ineffective erythropoiesis and hemolysis. The sideroblastic anemias are a heterogeneous group of pathological conditions, both clinically and pathogenetically. Heme synthesis appears to be regularly disturbed, but this is probably not the sole defect. Other alterations of globin and heme synthesis are listed and briefly discussed.

Anemia, Hemolytic↗
PubMed1975

An other look at iron: role in host pathogen interaction.

Iron, as participant of many biological processes is a prerequisite for life. Uptake, internal transport and storage by organisms is handled by highly specialized chemical systems endowed with strong metal binding affinities. Apart from the homeostatic function of iron-binding compounds they appear of significance for inter-species interactions. Thus, by tight binding transferrin withholds the iron from invading microorganisms required for their optimal growth. This bacteriostatic property of the iron transport protein is however partially overcome by small molecular substances synthesized by bacteria and successfully competing for the metal. The balance of such interaction is a complex one. Yet, strong evidence points to the crucial importance of the amount of iron offered by a host to infecting agents for determining the fate of bacterial disease.

Anemia, Hypochromic↗
PubMed1975

Functional heterogeneity of the transport iron compartment II. In vivo differences between transferrin iron binding sites, and in vitro interbinding site iron exchange.

First, an 80% 59Fe-saturated transferrin solution was exposed to reticulocytes to reduce its iron content. Iron-donating activity of the supernatant was subsequently compared to that of a fresh preparation equal in iron and transferrin concentration; it was found significantly reduced, but gradually improving in presence of 10(-3)M citrate. Second, two transferrin solutions saturated with 59FeCl3 or 56FeCl3 were exposed to reticulocytes and resaturated adding the opposite iron species. These preparations were injected into rats and the 59Fe plasma disappearance rate was followed; the 59Fe added after reticulocyte exposure was cleared more rapidly. It is concluded that citrate ions mediate interbinding site iron exchange. Further, iron distribution among binding sites is important for tissue iron delivery.

Animals↗