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M Webb

Publications and source records attributed to M Webb.

28 records · Page 2Linked to original sources
PubMed1976

Cadmium-thionein and the protection by cadmium against the nephrotoxicity of mercury.

Uptake of Hg2+ into the renal and hepatic metallothioneins of rats is increased by pretreatment with Cd2+. This increased uptake occurs both by displacement of Cd2+ (and of Zn2+) from the presynthesized cadmium-thionein, and by further synthesis of thionein. The former mechanism predominates in the kidney of the male rat, which is more sensitive than the female to Hg2+. The latter mechanism, which occurs particularly in the kidney of the female, also is considered to involve an initial displacement of Cd2+ from cadmium-thionein, but is followed by further synthesis of the metalloprotein, which is induced by the liberated cation. Pretreatment with Cd2+ increases not only the incorporation of Hg2+ into the renal metallothionein, but also the uptake of Hg2+ into other components of the kidney. At dose levels of Hg2+ at which Cd2+-pretreatment gives complete protection against the nephrotoxicity in male and female rats, the increase in Hg2+-uptake into both the particulate components and into the soluble fraction of the kidney is greater than into metallothionein. It is concluded, therefore, that binding of Hg2+ by pre-induced cadmium-thionein alone cannot explain the protection by Cd2+ against the nephrotoxicity of Hg2+.

Animals↗
PubMed1976

Influence of dietary cadmium on the distribution of the essential metals copper, zinc and iron in tissues of the rat.

The effect of long-term dietary cadmium treatment upon the distribution of the metals copper, iron and zinc has been compared in various organs of male and female rats. The renal accumulation of cadmium was similar in both sexes without a plateau being reached. In contrast, the hepatic accumulation of cadmium was higher in the female than in the male rat and a plateau was observed after 30-35 weeks of dietary cadmium treatment. Most of the cadmium which accumulated in these organs was recovered in the metallothionein fraction andthe concentration of hepatic cadmiumthionein in the female rat was correspondingly higher than in the male rat. Accumulation of cadmium was associated with an increased zinc concentration in the liver and an increased copper concentration in the kidney; these increases were correlated with increases in liver and kidney metallothioneins induced by cadmium. Uptake of cadmium into organs other than liver and kidney occurred to a small extent but was not associated with changes in the concentration of copper and zinc. Cadmium also accumulated in the intestinal mucosa where it could be recovered in a fraction corresponding to metallothionien. A loss of iron from the liver and kidney was also observed following dietary cadmium treatment and involved mainly a loss of iron from ferritin.

Administration, Oral↗
PubMed1975

Induced synthesis of metallothionein by pig kidney cells in vitro in response to cadmium.

Cells of a line (K7), derived from the cortex of the adult pig kidney, synthesize and accumulate high levels of metallothionein when grown in vitro in the presence of low concentrations (0.5 mug/ml) of Cd2+. This indicates that the accumulation of this protein in the kidneys of animals exposed to cadmium is due at least partly to synthesis in situ, and not solely to uptake by the renal cells of metallothionein produced by the liver. It is suggested that the ability to synthesize large amounts of metallothionein indicates the tubular origin of the cells of this line.

Animals↗
PubMed1975

Cadmium.

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Animals↗
PubMedDate not supplied

Inhibition of mixed lymphocyte response by monoclonal antibody specific for a rat T lymphocyte subset.

Cell-surface differentiation antigens which are associated with particular lymphocyte subsets are likely to be molecules which mediate specific functions of the cells which display them. One way to investigate this hypothesis is to see whether antibodies directed against such antigens will inhibit functional systems. This approach can be attempted with confidence if monoclonal antibodies are used, as these react with one antigenic determinant only and can be used in purified form. In this report we show that a monoclonal antibody which is specific for a subset of rat tT lymphocytes inhibits the mixed lymphocyte response (MLR). The antibody acts on the responder cells without killing them.

Animals↗
PubMedDate not supplied

Cross-cultural study of initial visits to psychiatric outpatient clinics.

This descriptive and comparative study explored issues involving initial visits to psychiatric outpatient clinics. Seventy patients in an Irish clinic and 51 patients in a United States clinic were interviewed and 100 medical records in each clinic were reviewed to examine data on five variables: presenting complaints, critical incidents, referral processes, patient expectations, and reactions to treatment plans. Commonalities and differences between clinics were cited.

Adolescent↗