Simultaneous inference of a binary composite endpoint and its components.

Binary composite endpoints offer some advantages as a way to succinctly combine evidence from a number of related binary endpoints recorded in the same clinical trial into a single outcome. However, as some concerns about the clinical relevance as well as the interpretation of such composite endpoints have been raised, it is recommended to evaluate the composite endpoint jointly with the involved components. We propose an approach for carrying out simultaneous inference based on separate model fits for each endpoint, yet controlling the familywise type I error rate asymptotically. The key idea is to stack parameter estimates from the different fits and derive their joint asymptotic distribution. Simulations show that the proposed approach comes closer to nominal levels and has comparable or higher power as compared to existing approaches, even for moderate sample sizes (around 100-200 observations). The method is compared to the gatekeeping approach and results are provided in the Supplementary Material. In two data examples we show how the procedure may be adapted to handle local significance levels specified through a priori given weights.

S100A7, S100A10, and S100A11 are transglutaminase substrates.

S100 proteins are a family of 10-14 kDa EF-hand-containing calcium binding proteins that function to transmit calcium-dependent cell regulatory signals. S100 proteins have no intrinsic enzyme activity but bind in a calcium-dependent manner to target proteins to modulate target protein function. Transglutaminases are enzymes that catalyze the formation of covalent epsilon-(gamma-glutamyl)lysine bonds between protein-bound glutamine and lysine residues. In the present study we show that transglutaminase-dependent covalent modification is a property shared by several S100 proteins and that both type I and type II transglutaminases can modify S100 proteins. We further show that the reactive regions are at the solvent-exposed amino- and carboxyl-terminal ends of the protein, regions that specify S100 protein function. We suggest that transglutaminase-dependent modification is a general mechanism designed to regulate S100 protein function.

The IOMC organisations: a source of chemical safety information.

The Inter-Organisation Programme for the Sound Management of Chemicals (IOMC) was established in 1995 as a mechanism to co-ordinate the efforts of Inter-governmental Organisations in promoting the sound management of chemicals. The seven participating organisations are the United Nations Environment Programme (UNEP), the International Labour Organisation (ILO), the United Nations Food and Agriculture Organisation (FAO), the World Health Organisation (WHO), the United Nations Industrial Development Organisation (UNIDO), the United Nations Institute for Training and Research (UNITAR), and the Organisation of Economic Cooperation and Development (OECD). Members consult on the planning, programming, implementation and monitoring of activities undertaken jointly or individually, and help ensure that programmes are mutually supportive, complementary and avoid duplication of efforts, thus meeting the overall needs of the users more efficiently and effectively. To deal with technical work, the IOMC established smaller thematic groups in the main programme areas of Agenda 21's Chapter 19. One such group promotes information exchange work. Within this IOMC framework, the seven organisations have developed approaches and products to help customers find chemical safety information, as well as improving modalities of access to these data. These mechanisms come in addition to and complement the extensive information products and databases developed and provided by the individual organisations. This article presents an overview of the role of each organisation, an introduction to its electronic information products and tools, and a discussion of the products of this joint effort.

Analysis of protein dimerization and ligand binding of orphan receptor HNF4alpha.

Hepatocyte nuclear factor 4alpha (HNF4alpha) (NR2A1), an orphan member of the nuclear receptor superfamily, binds DNA exclusively as a homodimer even though it is very similar in amino acid sequence to retinoid X receptor alpha (RXRalpha), which heterodimerizes readily with other receptors. Here, experimental analysis of residues involved in protein dimerization and studies on a reported ligand for HNF4alpha are combined with a structural model of the HNF4alpha ligand-binding domain (LBD) (residues 137 to 384). When K300 (in helix 9) and E327 (in helix 10) of HNF4alpha1 were converted to the analogous residues in RXRalpha (E390 and K417, respectively) the resulting construct did not heterodimerize with the wild-type HNF4alpha, although it was still able to form homodimers and bind DNA. Furthermore, the double mutant did not heterodimerize with RXR or RAR but was still able to dimerize in solution with an HNF4alpha construct truncated at amino acid residue 268. This suggests that the charge compatibility between helices 9 and 10 is necessary, but not sufficient, to determine dimerization partners, and that additional residues in the HNF4alpha LBD are also important in dimerization. The structural model of the HNF4alpha LBD and an amino acid sequence alignment of helices 9 and 10 in various HNF4 and other receptor genes indicates that a K(X)(26)E motif can be used to identify HNF4 genes from other organisms and that a (E/D(X)(26-29)K/R) motif can be used to predict heterodimerization of many, but not all, receptors with RXR. In vitro analysis of another HNF4alpha mutant construct indicates that helix 10 also plays a structural role in the conformational integrity of HNF4alpha. The structural model and experimental analysis indicate that fatty acyl CoA thioesters, the proposed HNF4alpha ligands, are not good candidates for a traditional ligand for HNF4alpha. Finally, these results provide insight into the mechanism of action of naturally occurring mutations in the human HNF4alpha gene found in patients with maturity onset diabetes of the young 1 (MODY1).

Intrasite sampling of Hong Kong soils contaminated by Caesium-137.

Previous measurements of soil contamination by Caesium-137 (137Cs) in Hong Kong have been used both to estimate background levels prior to the construction of the Guangdong Nuclear Power Station (GNPS) at Daya Bay and to evaluate health hazards arising from the radionuclide. These measurements are reviewed and contrasted with recent advances in understanding of 137Cs distribution in soil. Preliminary research findings are used to illustrate the microscale variability of 137Cs in the Hong Kong environment and to suggest intrasite sampling methods for establishing suitable reference values.

Modulation of transcriptional activation and coactivator interaction by a splicing variation in the F domain of nuclear receptor hepatocyte nuclear factor 4alpha1.

Transcription factors, such as nuclear receptors, often exist in various forms that are generated by highly conserved splicing events. Whereas the functional significance of these splicing variants is often not known, it is known that nuclear receptors activate transcription through interaction with coactivators. The parameters, other than ligands, that might modulate those interactions, however, are not well characterized, nor is the role of splicing variants. In this study, transient transfection, yeast two-hybrid, and GST pulldown assays are used to show not only that nuclear receptor hepatocyte nuclear factor 4 alpha1 (HNF4alpha1, NR2A1) interacts with GRIP1, and other coactivators, in the absence of ligand but also that the uncommonly large F domain in the C terminus of the receptor inhibits that interaction. In vitro, the F domain was found to obscure an AF-2-independent binding site for GRIP1 that did not map to nuclear receptor boxes II or III. The results also show that a natural splicing variant containing a 10-amino-acid insert in the middle of the F domain (HNF4alpha2) abrogates that inhibition in vivo and in vitro. A series of protease digestion assays indicates that there may be structural differences between HNF4alpha1 and HNF4alpha2 in the F domain as well as in the ligand binding domain (LBD). The data also suggest that there is a direct physical contact between the F domain and the LBD of HNF4alpha1 and -alpha2 and that that contact is different in the HNF4alpha1 and HNF4alpha2 isoforms. Finally, we propose a model in which the F domain of HNF4alpha1 acts as a negative regulatory region for transactivation and in which the alpha2 insert ameliorates the negative effect of the F domain. A conserved repressor sequence in the F domains of HNF4alpha1 and -alpha2 suggests that this model may be relevant to other nuclear receptors as well.

Studies in sugar chemistry. VII. Glucuronides of podophyllum derivatives.

The antitumor activities of several glucuronide methyl esters of podophyllum derivatives were tested in vitro against two human tumor cell lines and their drug resistant sublines. The most active compound studied was methyl (4'-carbobenzoxy-4'-demethyl-epipodophyllotoxin-D-glucopyranoside)uronat e 19. Compound 19 was as potent in a colon carcinoma model and was twice as potent in a lung carcinoma model as etoposide 6. In vivo, however, in a mouse leukemia P388 model, it had only marginal activity, with a maximum T/C% value of 125 at 37 mg/kg (iv).

The origin of life: philosophical perspectives.

In this paper I consider the work which has been done on The Origin of Life in the last 100 years. It is my argument that a great deal of the underpinning of discussions on this topic have been more philosophical than anything based in brute experience or theory.

Evolution and progress.

The concept of progress is one which makes evolutionists feel very uneasy, yet it is also a concept to which they are forever returning. It is useful to make a distinction between 'comparative progress' which involves competition between groups, and 'absolute progress' which involves the climb up some objective scale. Both kinds of progress have been the subject of much debate in recent years, leading one to turn from expectations that the controversy will ever be resolved to queries about why it continues to obsess so many people.

Novel anticancer prodrugs of butyric acid. 2.

The antitumor activity of novel prodrugs butyric acid was examined. The in vitro effect of the compounds on induction of cytodifferentiation and on inhibition of proliferation and clonogenicity showed that (pivaloyloxy)methyl butyrate (1a) (labeled AN-9) was the most active agent. SAR's suggested that its activity stemmed from hydrolytically released butyric acid. In vivo, 1a displayed antitumor activity in B16F0 melanoma primary cancer model, manifested by a significant increase in the life span of the treated animals. Murine lung tumor burden, induced by injection of the highly metastatic melanoma cells (B16F10.9), was decreased by 1a. It also displayed a significant therapeutic activity against spontaneous metastases which were induced by 3LL Lewis lung carcinoma cells. Moreover, 1a has the advantage of low toxicity, with an acute LD50 = 1.36 +/- 0.1 g/kg (n = 5). These results suggest that 1a is a potential antineoplastic agent.

The effect of methimazole on thioamide bioactivation and toxicity.

The hepatotoxicity induced by administration of ethionamide and thionicotinamide (TNA) was shown to be decreased by pre-administration of methimazole (MMI). Pre-administration of MMI was also shown to decrease the levels of excretion of TNA S-oxide. This indicates that thioamide S-oxidation, mediated by the flavin-containing mono-oxygenase, may be linked to the initiation of hepatotoxicity induced by these thioamides. SK&F-525-A, the cytochrome P-450 inhibitor, did not affect either thioamide-induced toxicity or levels of excretion of TNA S-oxide; however, the role of the P-450 isoenzymes cannot be totally ruled out.

Derivatives of butyric acid as potential anti-neoplastic agents.

A novel derivative of butyric acid, pivalyloxymethyl butyrate (AN-9) has been shown, in vitro, to: (a) induce cytodifferentiation and inhibit the proliferation of leukemic cells; (b) inhibit the growth and formation of Lewis lung carcinoma colonies in semi-solid agar. AN-9 affect cells at about 10-fold lower concentration and at a faster rate than does butyric acid. The pivalyloxymethyl esters of propionic, isobutyric and valeric acids do not elicit effects similar to those of AN-9, while the isobutyryloxymethyl butyrate does, which strongly suggests that the activity of AN-9 stems from intracellular metabolic degradation of the pro-drug to butyric acid. In vivo, AN-9, increased the survival of mice in Lewis lung carcinoma primary cancer model and significantly decreased the number of lung lesions of the animals inoculated with highly metastatic cells, but did not affect their life span. Acute LD50 studies have shown that AN-9 possesses low toxicity. These results suggest that AN-9 is a potential anti-neoplastic agent as well as a tool for investigation of the differentiation induction mechanism.

The metabolism of thionicotinamide in the rat.

The metabolism of the thioamide, thionicotinamide, in the male Wistar rat is described. Thionicotinamide was shown to be metabolised to inorganic sulphate, thionicotinamide S-oxide and also N1-methylnicotinamide, which arises from N-methylation of nicotinamide via desulphuration of the parent thioamide. At 24 hours from dosing about 35% of the dose had been excreted as inorganic sulphate and 20.5% as the S-oxide metabolite. Three metabolites, detected by their fluorescence under UV light, have not been positively identified but are postulated to be pyridones, resulting from ring oxidation, by analogy with other thioamides. S-Oxidation is an important metabolic pathway as it may give rise to toxic intermediates.

Teleology in biology: Is it a cause for concern?

Evolutionary biology is distinctively forward looking or 'teleological' in its way of thought. In this, it distinguishes itself from the physical sciences. One can ask for the purpose or function of the stegoseaur's fins. One would never ask for the function of a planet. Many, including biologists, worry that such teleology is an unhappy legacy of a Christian past. Although teleology does have its roots in pre-evolutionary thought, there are good reasons why it has persisted, and there are equally good reasons why it should be cherished.

Nature/nurture: reflections on approaches to the study of homosexuality.

There is understandable apprehension by many people towards claims that biology plays a significant role in the etiology of homosexuality. These worries should not be allowed to deter any such work on sexual orientation. It is argued that the only proper way to evaluate biological analyses is against the full background of Darwinian evolutionary theory. Moral issues pertaining to biological research on homosexuality are addressed. Finally, it is urged that both biological and environmental factors be considered in rendering a true picture of homosexuality.

Medicine as social science: the case of Freud on homosexuality.

This paper considers the question of whether the explanation of homosexual orientation offered by Sigmund Freud qualifies as a genuine explantation, judged by the criteria of the social sciences. It is argued that the explanation, namely that homosexual orientation is a function of atypical parental influences, is indeed an explanation of the kind found in the social sciences. Nevertheless, it is concluded that to date Freud's hypotheses about homosexuality are no more than unproven speculations. Also considered is the question of whether the very topic of homosexuality falls or ought to fall within the domain of medical inquiry.