Exploring human biology with N-of-1 clinical trials.

Studies on humans that exploit contemporary data-intensive, high-throughput 'omic' assay technologies, such as genomics, transcriptomics, proteomics and metabolomics, have unequivocally revealed that humans differ greatly at the molecular level. These differences, which are compounded by each individual's distinct behavioral and environmental exposures, impact individual responses to health interventions such as diet and drugs. Questions about the best way to tailor health interventions to individuals based on their nuanced genomic, physiologic, behavioral, etc. profiles have motivated the current emphasis on 'precision' medicine. This review's purpose is to describe how the design and execution of N-of-1 (or personalized) multivariate clinical trials can advance the field. Such trials focus on individual responses to health interventions from a whole-person perspective, leverage emerging health monitoring technologies, and can be used to address the most relevant questions in the precision medicine era. This includes how to validate biomarkers that may indicate appropriate activity of an intervention as well as how to identify likely beneficial interventions for an individual. We also argue that multivariate N-of-1 and aggregated N-of-1 trials are ideal vehicles for advancing biomedical and translational science in the precision medicine era since the insights gained from them can not only shed light on how to treat or prevent diseases generally, but also provide insight into how to provide real-time care to the very individuals who are seeking attention for their health concerns in the first place.

Dislocations in Si nanocrystals embedded in SiO2.

Si nanocrystals (Si nc) were formed by the implantation of Si(+) into a SiO2 film on (100) Si, followed by high-temperature annealing. High-resolution transmission electron microscopy has been used to investigate the dislocations in the Si nc produced by a high-dose (ion fluence of 3 x 10(17) cm(-2)) implantation. Three different kinds of dislocations, namely perfect, extended and mismatch dislocations, have been observed in some Si nc. The possible formation mechanism for these dislocations has been discussed. The dislocations in the Si nc are expected to have a great influence on the photoluminescence from Si nc embedded in SiO2.

Coalescence Behavior of Gold Nanoparticles.

The tetraoctylammonium bromide (TOAB)-stabilized gold nanoparticles have been successfully fabricated. After an annealing of the as-synthesized nanoparticles at 300 degrees C for 30 min, the coalescence behavior of gold nanoparticles has been investigated using high-resolution transmission electron microscopy in detail. Two types of coalescence, one being an ordered combination of two or more particles in appropriate orientations through twinning, and the other being an ordered combination of two small particles with facets through a common lattice plane, have been observed.

Selenium supplementation of children in a selenium-deficient area in China: blood selenium levels and glutathione peroxidase activities.

Keshan disease is a cardiomyopathy restricted to the endemic areas of China and seen in residents having an extremely low selenium (Se) status. Prophylactic administration of sodium selenite has been shown to decrease significantly the incidence of acute and subacute cases. The aim offthe study was to assess the relative bioavailability of selenite versus organic Se-yeast in a Se-deficient area in China with a randomized double-blind double-dummy design. Healthy children (n=30) between 14 and 16 yr of age were randomized into three equal groups receiving either 200 microg/d selenite Se or 200 microg/d Se-yeast or placebo for 12 wk. Blood was drawn at baseline, 4, 8, and 12 wk and 4 wk postsupplementation. The plasma Se concentration (mean +/- SD) was 0.16+/-0.03 micromol/L at baseline. Selenite and Se-yeast supplementation increased plasma Se to plateau values, 1.0+/-0.2 and 1.3+/-0.2 micromol/L, respectively. In red cells, Se-yeast increased the selenium level sixfold and selenite threefold compared to placebo. The relative bioavailability of Se-yeast versus selenite measured as glutathione peroxidase (GSHPx) activity was similar in plasma, red blood cells, and platelets. GSHPx activity reached maximal levels in plasma and platelets of 300% and 200%, respectively, after 8 wk compared to the placebo group, but continued to increase in red cells for 16 wk. Our study showed that although both forms of Se were equally effective in raising GSHPx activity, Se-yeast provided a longer lasting body pool of Se. Se-yeast may be a better alternative to selenite in the prophylaxis of Keshan disease with respect to building up of body stores.

Further investigation on the role of selenium deficiency in the aetiology and pathogenesis of Keshan disease.

Selenium supplements were not able to restore the ultrastructural changes in the myocardium of latent Keshan disease patients taken by using cardiac catheter endomyocardial biopsy. Observations on the changes of selenium status and the incidence of Keshan disease showed that new latent and naturally-occurring chronic cases were found in the endemic area even after selenium levels had been elevated in the residents to the levels typical in the non-endemic area. These results indicate that although selenium deficiency might be a primary pathogenetic geogen in the occurrence of Keshan disease, it is rather a conditional predisposing factor than a specific or initiative aetiologic factor for the occurrence of Keshan disease. Selenium supplementation could apparently alleviate the higher platelet responsiveness of residents in the endemic area, which might contribute to eliminating the basis for the occurrence of the multifocal perivascular necroses in myocardium of acute and subacute Keshan disease.

[Studies on the metabolism of antiepilepserine in isolated perfused rat liver].

The metabolism of antiepilepserine, 3,4-methylene dioxycinnamyl piperidine, was studied in isolated perfused rat liver. Two metabolites were separated and purified by means of HPLC. They were identified as 3,4-methylene dioxycinnamyl hydroxypiperidine and 4-hydroxy-3-methoxycinnamyl piperidine by UV and MS. The latter was further confirmed by chemical synthesis. The pharmacokinetics of antiepilepserine in isolated perfused liver was also studied. Parameters obtained include a first order elimination constant, k = 0.0157 +/- 0.0043 min-1, and a half-life, t 1/2 = 46.7 +/- 11.9 min, (n = 6). The amount of antiepilepserine lost during the perfusion could not be compensated by the increased amount of metabolites. Antiepilepserine was found to be tightly bound and stored in the liver. This might be one of the explanations of the first pass effect of antiepilepserine after oral administration.

The synthesis of protective fragments of alpha-human atrial natriuretic polypeptide (alpha-hANP).

In this paper the synthesis of alpha-human atrial natriuretic polypeptide fragments (positions, 1-4, 5-10, 11-16, 17-22, 23-28) by solution method is reported. In the synthesis of some peptides, the results from mixed anhydride procedure and active ester procedure are compared. In the synthesis of other peptides, the effects of reaction temperature, basicity of catalyst, and reaction time on the specific rotations and yields of these compounds are observed. The sequence of amino acids of all the protective polypeptides is confirmed by FAB-MS.