The binding of Cu(II), Zn(II), Ni(II), and Cd(II) to protein components in serum, placenta, kidney, and urine was investigated at physiological pH, using radioisotopes as tracers. All the four metals were bound to albumin and other macromolecules in serum. However, small amounts were also bound to low molecular weight components of the size 1500-10000 daltons. The nature of the Cu(II)-binding to alpha-fetoprotein suggests its important role as the Cu(II)-transporting protein in fetal life. Metal binding to placental components were studied using both rat placenta and isolated human trophoblast cells. Studies of metal binding targets in kidney resulted in the isolation of a 4000 daltons acidic polypeptide which binds Ni(II) and Cd(II) with Kapp = 1.1 x 10(-5) and 2.3 x 10(-5), respectively. Studies of metal binding substances in urine reveals the major amounts of these metals binding to substances of molecular weight 500-5000 daltons. Preliminary amino acid analysis suggests these components rich in acidic amino acids, similar to what has been found with kidney polypeptide. There may be a general role for such compounds in the handling of metals in the process of excretion.

Amino Acids↗

PubMedDate not supplied

Role of glutathione in selenite binding by human plasma.

The erythrocyte-mediated reduction of selenite has been reproduced by the addition of reduced glutathione to plasma at levels comparable to those present in the erythrocyte. The reaction has been followed by chromatography and ultraviolet (UV) absorption spectroscopy (in the absence of plasma). The first detectable compound, selenium diglutathione, is very unstable in physiological conditions. The product of the reaction does not contain glutathione and is able to react and incorporate selenium into plasma proteins without the participation of hemoglobin or glutathione reductase. A saturable low molecular weight compound is also able to bind selenium, which may be relevant in the initial distribution and excretion of selenium after selenite administration.

Blood Proteins↗

PubMedDate not supplied

Selenite metabolism in rat and human blood.

The binding of selenite, the form of selenium used in the treatment of Keshan disease, to plasma proteins and the role of erythrocytes in this process have been studied. The experiments were carried out by incubating 75Se as selenite with plasma and whole blood in vitro (human and rat) and in vivo (rat) and subsequent fractionation by Sephadex G-150 gel filtration. Human and rat plasma proteins were unable to incorporate selenium from selenite, as shown by the negligible amount present in proteins after incubation of plasma with selenite. The incorporation can be carried out after internalization of selenite by the erythrocytes in a fast, temperature dependent process. Hemoglobin, being the major binding protein for the newly reduced selenium in the erythrocyte, might have a role in the uptake of selenite by erythrocytes. The greater affinity of plasma proteins for the final selenium compound resulting from reduction could be the cause of the efflux. However, this is minimal in the absence of plasma, as is evident from the results obtained from blood reconstituted with saline solution instead of plasma. At least two proteins, one albumin like, probably albumin itself and the other of molecular weight close to or greater than 200,000 in the plasma, are involved in the binding and efflux processes.

Animals↗

PubMedDate not supplied

Outcome of "kissing stents" for aortoiliac atherosclerotic disease, including the effect on the non-diseased contralateral iliac limb.

PURPOSE: To assess outcomes following "kissing stents" for aortoiliac atherosclerotic disease, particularly in the non-diseased/non-symptomatic limb. METHODS: Twenty-four patients underwent kissing stenting over 36 months. There were 36 symptomatic and 12 non-symptomatic/non-diseased limbs. Patients were prospectively followed with 3-monthly clinical assessment as well as duplex ultrasound. RESULTS: At 23.5 months follow-up (range 3-36 months), 75% of patients had improvement in symptoms, 20% no change and 5% had deterioration. Sixty-one percent of limbs maintained an increase in ankle-brachial pressure index of >0.1. There were 15 reinterventions in nine patients, including three in non-symptomatic/non-diseased limbs. Primary patency at 6, 12 and 24 months was 94%, 81% and 58%, respectively. Primary assisted and secondary patency rates were 96%, 84% and 84% respectively for diseased limbs, and 92% and 100% for non-symptomatic/non-diseased limbs. Although reinterventions were required, there were no long-term occlusions in the non-diseased/non-symptomatic limb. CONCLUSION: Kissing stents offer an invaluable alternative to surgery. There were no long-term occlusions following kissing stents in a previously non-symptomatic/non-diseased limb.

Aged↗

PubMedDate not supplied

Thresholds of intracranially recorded auditory field potentials in the pigeon compared with compound action potential thresholds.

The compound action potential (CAP) thresholds provide a reliable indicator for cochlear functional integrity during experimentation in birds as well as in mammals. However, if experimental manipulations are necessary in the middle ear/inner ear spaces, the round window electrodes are often inconvenient. In search for an alternative for CAP recordings, intracranial recordings of acoustically evoked field potentials from the nucleus angularis/magnocellularis were made in pigeons using stereotactically placed electrodes. The responses were compared with those recorded from intracranial surface electrodes placed on the dura mater and compared with CAP responses recorded from the round window. The field potentials recorded from the nucleus angularis/magnocellularis contain a significant contribution from the auditory nerve, as large in amplitude as the CAP recorded at the round window. The recordings from the intracranial surface electrodes were noisier and the contribution from the auditory nerve was too small to be used as a fast monitor of the condition of the inner ear. Threshold curves as a function of frequency could be determined with an automated method from the nucleus angularis/magnocellularis with the same sensitivity and accuracy as from the round window CAP within a few minutes. These results demonstrate that stereotactic recordings of field potentials from the nucleus magnocellularis/angularis region are a suitable alternative to reliably monitor the condition of the inner ear when round window electrodes cannot be used.

Animals↗

PubMedDate not supplied

Studies of induction of metallothionein in JAr (human choriocarcinoma) cells by cis and trans isomers of diamminedichloroplatinum (II) and their hydrolyzed species.

The inducibility of metallothionein by cis- and trans-diamminedichloroplatinum(II) and their hydrolyzed products was studied in the JAr (a human choriocarcinoma) cell line. The metallothionein present in the cytosolic fraction of these cells was measured after a 12- or 24-h exposure to a fresh metal solution or a solution that had been allowed to hydrolyze. These results demonstrate that hydrolysis of the cis isomer produces a species that is able to give a 374% increase in the cytosolic level of metallothionein after a 24-h exposure to 40 microM of the metal. Fresh cisplatin, on the other hand, gives a maximal increase of 118% under the same conditions. Transplatin and its hydrolyzed species did not induce metallothionein. These results may indicate that hydrolysis of cisplatin performs an important role in the metabolism and possibly the toxicity of this widely used agent for cancer chemotherapy.

Biotransformation↗