Biomedical subjects

M Oven

Publications and source records attributed to M Oven.

3 recordsLinked to original sources

PubMed2001

Homo-phytochelatins are synthesized in response to cadmium in azuki beans.

In a recent report, it was claimed that azuki beans (Vigna angularis) do not synthesize phytochelatins (PCs) upon exposure to cadmium, although glutathione (GSH), the substrate for PC synthesis, is present in this plant. This legume species thus would be the first exception in the plant kingdom that would fail to complex heavy metals by PCs. Here, we report that not GSH, but only homoglutathione can be detected in this plant and that homo-phytochelatins are formed when azuki beans are challenged with heavy metals such as cadmium. We also show that the 5,5'-dithiobis(2-nitrobenzoic acid)-oxidized GSH reductase recycling assay, used for GSH quantification in the recent study of heavy metal tolerance in azuki beans, reacts both with GSH and homoglutathione and therefore cannot be used when biological samples should be analyzed exclusively for GSH.

Cadmium↗

PubMed2000

Detoxification of arsenic by phytochelatins in plants.

As is a ubiquitous element present in the atmosphere as well as in the aquatic and terrestrial environments. Arsenite and arsenate are the major forms of As intoxication, and these anions are readily taken up by plants. Both anions efficiently induce the biosynthesis of phytochelatins (PCs) ([gamma-glutamate-cysteine](n)-glycine) in vivo and in vitro. The rapid induction of the metal-binding PCs has been observed in cell suspension cultures of Rauvolfia serpentina, in seedlings of Arabidopsis, and in enzyme preparations of Silene vulgaris upon challenge to arsenicals. The rate of PC formation in enzyme preparations was lower compared with Cd-induced biosynthesis, but was accompanied by a prolonged induction phase that resulted finally in higher peptide levels. An approximately 3:1 ratio of the sulfhydryl groups from PCs to As is compatible with reported As-glutathione complexes. The identity of the As-induced PCs and of reconstituted metal-peptide complexes has unequivocally been demonstrated by electrospray ionization mass spectroscopy. Gel filtration experiments and inhibitor studies also indicate a complexation and detoxification of As by the induced PCs.

Arsenic↗

PubMed1996

Cognitive therapy for multiple sclerosis: a preliminary study.

BACKGROUND: Drug treatments for multiple sclerosis are expensive, may cause side effects, and do not have demonstrated efficacy for cognitive deficits associated with this disease. OBJECTIVE: To test the effectiveness of a multimodal cognitive therapy on cognitive and physical measures known to be affected in multiple sclerosis. DESIGN: Quasi-experimental wait-list control. SETTING: Alternative medicine clinic. PATIENTS: 27 persons with clinically definite multiple sclerosis. INTERVENTION: Multimodal cognitive therapy. MAIN OUTCOME MEASURES: Neuropsychological measures of verbal learning and memory, abstraction, vocabulary, and information processing speed; Beck Depression Inventory; tactile sensitivity of the hands; grip strength; and visual acuity. MAIN RESULTS: 12 of 14 patients in the therapy group and 10 of 13 patients in the control group completed 24 weeks of treatment and all assessments. Patients who received therapy showed significantly greater improvement in verbal learning, verbal abstraction, depression, and some measures of grip strength and tactile sensitivity than did patients in the untreated control group. The groups did not differ in the magnitude of change on vocabulary, information processing speed, or visual acuity. CONCLUSION: Cognitive therapy appears to be a promising treatment for ameliorating some symptoms of multiple sclerosis. A larger study with a randomized design and additional outcome measures is warranted.

Adult↗