The use of high-selenium yeast to raise selenium status: how does it measure up?

Selenium-enriched yeast (Se-yeast) is a common form of Se used to supplement the dietary intake of this important trace mineral. However, its availability within the European Union is under threat, owing to concerns expressed by the European Community (EC) Scientific Committee on Food that Se-yeast supplements are poorly characterised and could potentially cause the build up of Se in tissues to toxic levels. The present review examines the validity of these concerns. Diagrams of the biosynthesis and metabolism of Se compounds show which species can be expected to occur in Se-yeast preparations. Se-yeast manufacture is described together with quality-control measures applied by reputable manufacturers. The way in which speciation of Se-yeast is achieved is explained and results on amounts of Se species in various commercial products are tabulated. In all cases described, selenomethionine is the largest single species, accounting for 54-74 % of total Se. Se-yeast is capable of increasing the activity of the selenoenzymes and its bioavailability has been found to be higher than that of inorganic Se sources in all but one study. Intervention studies with Se-yeast have shown the benefit of this form in cancer prevention, on the immune response and on HIV infection. Of about one dozen supplementation studies, none has shown evidence of toxicity even up to an intake level of 800 microg Se/d over a period of years. It is concluded that Se-yeast from reputable manufacturers is adequately characterised, of reproducible quality, and that there is no evidence of toxicity even at levels far above the EC tolerable upper intake level of 300 microg/d.     

Low selenium status is associated with the occurrence of the pregnancy disease preeclampsia in women from the United Kingdom

OBJECTIVE: Because the trace element selenium behaves as an antioxidant and peroxynitrite scavenger when incorporated into selenoproteins, our objective was to determine whether low selenium status was associated with a greater risk of occurrence of preeclampsia. STUDY DESIGN: Fifty-three preeclamptic patients and 53 matched pregnant controls at the John Radcliffe Hospital, Oxford, gave clippings of their toenails (laid down from 3-12 months previously) for selenium determination by neutron activation analysis. Clinical characteristics of the women and their infants were recorded. Statistical analysis was by Wilcoxon signed rank test and odds ratios were calculated by the ratio of discordant pairs. RESULTS: Median toenail selenium concentrations in the preeclamptic subjects were significantly lower than in their matched controls (P=.001). Being in the bottom tertile of toenail selenium was associated with a 4.4-fold (95% CI 1.6-14.9) greater incidence of the condition. Within the preeclamptic group, lower selenium status was significantly associated (P=.029) with more severe expression of disease, as measured by delivery before 32 weeks. CONCLUSION: In the light of the reduction in selenium status in a number of European countries in recent years, this study raises the question of whether a small increase in selenium intake might help prevent preeclampsia in susceptible women.     

New treatments for diabetic neuropathy: Symptomatic treatments

Painful diabetic neuropathy is a common distressing and challenging condition. The mechanism or mechanisms involved in its pathogenesis continue to elude clinical scientists. As with other conditions of painful distal symmetrical neuropathic conditions, pain relief involves the use of a variety of analgesic and neuroleptic drugs, aimed at reducing either central responses to painful stimuli or at dampening spontaneous irritability of affected neurons. More recently, several therapies directed at putative pathologic mechanisms specific to painful diabetic neuropathy have evolved. These include vasodilators, protein kinase C β inhibition, antioxidants, and novel aldose reductase inhibitors. Preliminary clinical studies of these therapies have at present involved small numbers of patients; however, the results have been encouraging. This article considers the clinical aspects of diagnosis and management of chronic painful diabetic neuropathy, focusing on existing and newer therapies.     

Peanut allergy in-flight

An unknown but probably significant number of airline passengers are allergic to peanuts. Reactions can be mild, moderate, or severe (life threatening). Because peanuts are sometimes dispensed by flight attendants on commercial flights, there is public concern that passengers are at risk of an in-flight allergic reaction. Although there is little in the medical literature to substantiate this concern, there are anecdotal cases of inflight allergic reactions to peanuts from ingestion, dermal contact, and inhalation of airborne peanut particles. Consequently, there are several options among which the airlines must choose in order to satisfy passenger concerns.     

A comparison of robot-assisted versus manually constructed endoscopic coronary anastomosis

BACKGROUND: New technology has enabled surgeons to attempt totally endoscopic coronary artery bypass grafting. Our purpose was to compare three different techniques of totally endoscopic anastomosis using a porcine animal model. METHODS: Porcine hearts were excised and the right coronary artery was dissected free for use as an arterial graft. The hearts were placed in a human thoracic model and an endoscopic arterial anastomosis between the free right coronary artery and the left anterior descending coronary artery was performed using one of the following: (1) two-dimensional visualization with straight endoscopic instruments (n = 8); (2) three-dimensional head-mounted visualization with curved endoscopic instruments (n = 7); or (3) three-dimensional visualization with robotic telemanipulation (n = 8). Pathologic analysis of suture placement, vessel trauma, and patency was performed. Anastomoses were graded according to quality, ease, and patency using a seven-point Likert scale (1 = excellent, 7 = very poor). RESULTS: Endoscopic anastomotic ease and quality were significantly improved when three-dimensional visualization and curved endoscopic instruments were employed. Telemanipulation enhanced the process and provided the best operative results with regard to time required to construct the anastomosis, as well as ease and quality. CONCLUSIONS: Totally endoscopic anastomosis is feasible using currently available technology. Three-dimensional visualization and robotic telemanipulation significantly facilitate anastomosis construction and will likely benefit clinical operative outcome.