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Biomedical subjects

S Mann

Publications and source records attributed to S Mann.

At least 199 records · Page 11Linked to original sources
PubMed1975

[Changes in serum osmolarity after high contrast doses during angiography].

Analysis of changes in osmolarity of the serum after various doses of hypertonic radiographic contrast media, following a single injection, showed an initial rise of about 35 m/mosm/1, followed by a rapid fall in osmolarity with a subsequent short hypo-osmolar phase. With repeated injections, similar changes are found if the intervals between the injections are long enough. Following repeated injections over a short interval, there may be a more prolonged phase of hyperosmolarity. In this phase of delayed dehydration, there may be clinical complications. Possible forms of treatment are discussed.

Angiography↗
PubMedDate not supplied

Magnetoferritin: characterization of a novel superparamagnetic MR contrast agent.

A protein-encaged superparamagnetic iron oxide has been developed and characterized by using horse spleen apoferritin as a novel bioreactive environment. The roughly spherical magnetoferritin molecules, 120 A in diameter, are composed of a monocrystalline maghemite or magnetite core 73 A +/- 14 in diameter. Except for the additional presence of iron-rich molecules of higher molecular weight, the appearance and molecular weight (450 kd) of magnetoferritin are identical to that of natural ferritin; the molecules are externally indistinguishable from their precursor, with a pI (isoelectric point) in the range 4.3-4.6. The measured magnetic moment of the superparamagnetic cores is 13,200 Bohr magnetons per molecule, with T1 and T2 relaxivities (r1 and r2) of 8 and 175 L.mmol-1 (Fe).sec-1, respectively, at body temperature and clinical field strengths. The unusually high r2/r1 ratio of 22 is thought to arise from ideal core composition, with no evidence of crystalline paramagnetic inclusions. T2 relaxation enhancement can be well correlated to the field-dependent molecular magnetization, as given by the Langevin magnetization function, raised to a power in the range 1.4-1.6. With its nanodimensional biomimetic protein cage as a rigid, convenient matrix for complexing a plethora of bioactive substances, magnetoferritin may provide a novel template for specific targeting of selected cellular sites.

Animals↗
PubMedDate not supplied

Isolation and properties of the complex nonheme-iron-containing cytochrome b557 (bacterioferritin) from Pseudomonas aeruginosa.

A nonheme-iron-containing cytochrome b557, also known as bacterioferritin, was isolated from Pseudomonas aeruginosa. Gel electrophoresis showed that the protein subunits had a molecular weight of 18 kD and it is suggested that the intact molecule contained 24 subunits. The isolated protein contained 8.7% by weight Fe and 8% by weight phosphate. Most of the Fe was contained in the nonheme-iron core and could be readily removed by dialysis against 0.12 M thioglycollic acid. The resulting apobacterioferritin contained approximately one protoporphyrin IX group for every five subunits and, in addition, an unidentified fluorophor. The nonheme-iron core was found to be amorphous with a mean core size of 60-65 A.

Bacterial Proteins↗