Jean-Christophe Doré

Changes in stone composition according to age and gender of patients: a multivariate epidemiological approach

Urinary stone incidence and composition have changed markedly over the past half-century in industrialized countries, in parallel with profound changes in living standards and dietary habits, with a dramatic increase in the incidence of calcium oxalate stones. However, studies evaluating the influence of age and gender on the distribution of the various types of urinary calculi are scarce. We report the results of a study based on 27,980 calculi (from 19,442 males and 8,538 females) analyzed by infrared spectroscopy between 1976 and 2001. The relationships between age and sex and stone composition were investigated using a multivariate approach, based on correspondence factor analysis (CFA). We found a male predominance for calcium oxalate and uric acid, a female preponderance for calcium phosphate and struvite stones, and an increasing prevalence of uric acid stones with age in both genders. CFA was able to reconstruct in blind the age curve from stone composition. The first two axes of the multidimensional classification, which correspond to age, included 86.9% of the total variance, indicating that age was the main factor involved in stone type. Superimposition of age classes and stone components showed a strong relationship between age and whewellite, weddellite, brushite, carbapatite, octacalcium phosphate and uric acid, while other substances (whitlockite, amorphous carbonated calcium phosphate, struvite, proteins, mucopolysaccharides, triglycerides or ammonium urate) appeared weakly related to age. In addition, CFA suggests the role of common lithogenic factors between weddellite, carbapatite and brushite, which clustered in the same area, whereas the various crystalline forms of phosphate stones segregated into two different clusters, suggesting distinct pathogenic factors. In conclusion, this study provides a picture of the present epidemiology of urinary stones in France. CFA helped to confirm: (1) an etiopathogenic distinction between weddellite and whewellite, (2) etiopathogenic associations between chemical compounds, which were only suspected on a clinical basis, and (3) suggested yet unrecognized associations, especially with respect to the heterogeneous group of phosphate stones.

Update on metal content profiles in mushrooms--toxicological implications and tentative approach to the mechanisms of bioaccumulation.

Fifteen metals (macroelements, heavy metals and trace elements) have been investigated using inductively coupled plasma-atomic emission spectrometry (ICP-AES) on 92 specimens of mushrooms collected in France, in the Paris region. Their levels and distributions are given. Taking in account the respective contents and bioaccumulation abilities, the data reveal that different mechanisms are involved depending on fungi species and genera besides physicochemical influences. Moreover, they suggest that the different elements might accumulate through various ways that are successively mentioned. Metabolic, toxicological and environmental significances are discussed.

Structure of International Collaboration in Science : Typology of countries through multivariate techniques using a link indicator

In this article patterns of international collaboration in science are investigated using a specific procedure to analyse data collected from theScience Citation Index. We develop an indicator based on the scientific linkages between countries established through internationally co-authored articles (COPs). The credibility, advantages and uses of this indicator are discussed. We apply the Correspondence Factorial Analysis method and the Minimum Spanning Tree classification to this indicator in order to observe the level of resemblance and the main characteristics of the collaboration structured by 98 countries in eight principal fields of science. The results shown summarize the diverse aspects of countries participating in collaborative works and bring into view the cognitive structure of international research. The use of these methods in the investigation of international collaboration contributes to the analysis of the complex structure of the scientific communities of different countries.

Correspondence factor analysis of the publication patterns of 48 countries over the period 1981–1992

This study illustrates the application of a descriptive multivariate statistical method, Correspondence Factorial Analysis (CFA), to the analysis of a dataset of over 6 million bibliometric entries (data from ISI). CFA is used to show how the 48 most prolific nations stand in relation to each with regard to their publication interests in 17 specific disciplinary areas and one multidisciplinary field over the period 1981-1992. The output of a CFA is a map displaying proximity among variables (countries and disciplines) and constitutes an impartial working document for experts interested in the evaluation of science. The present study focuses on three aspects of a CFA : (1) The normalized publication patterns of countries with a common feature ( e.g., that belong to the same geopolitical zone, economic union, etc.) can be pooled in order to highlight the position of the union with respect to individual countries ; (2) complex CFA maps can be simplified by selecting reference countries or disciplines and observing how the remaining countries and disciplines relate to these references ; (3) data on additional countries (new publication profiles) or on additional variables (e.g., socio-economic data on all the countries under study) can be introduced into the CFA maps used as mathematical models. Our CFA of the ISI dataset reveals the scientific interests of nations in relative terms. The main cleavage (the first factorial axis) is between countries that still concentrate on the disciplines of the industrial revolution such as physics and chemistry (or that have turned toward their offspring, materials sciences) and those that have veered toward more modern disciplines such as the life sciences (e.g., clinical medicine), the environment, and computer sciences. The second cleavage, along the second factorial axis, is between countries that focus on the agricultural sciences (the land surface) and those interested in the geosciences (the sea, earths mantle, and mining). The third and fourth axes discriminate even further between earth, life, and abstract sciences highlighting the ostensible relationship between (organic) chemistry and all life science disciplines and between physics and disciplines related to engineering, materials sciences, etc. The CFA maps disclose the specific behavior of each country with respect to these cleavages.

Influence of di- and tri-phenylethylene estrogen/antiestrogen structure on the mechanisms of protein kinase C inhibition and activation as revealed by a multivariate analysis

We have performed a systematic study of the interaction of 36 di- and tri-phenylethylene derivatives (DPEs and TPEs) with protein kinase C (PKC). The results were submitted to a multivariate analysis in order to identify the structural features that might be implicated in interference with the activity of three PKC subspecies under three enzyme activation conditions. Four groups of test-compounds, each with common chemical features, could be distinguished clearly. The first group comprised all TPEs substituted with at least one basic dialkylaminoethoxy side-chain. These inhibited type alpha, beta and gamma PKC subspecies activated by Ca2+ and phosphatidylserine (PS) with or without diolein (DO) at micromolar concentrations but did not inhibit protamine sulfate phosphorylation. The other effectors, which all possessed a 1,1-bis-(p-hydroxyphenyl) ethylene moiety, influenced PKC activity at high concentrations (30-200 microM) and could be divided into two groups. One group constituted PKC inhibitors in the TPE series and inhibited PKC activated by Ca2+, PS and DO, as well as protamine sulfate phosphorylation. The other group constituted dual-type inhibitors/activators in the DPE series and stimulated PKC in the presence of Ca2+ and low PS concentrations but inhibited the enzyme in the simultaneous presence of DO. The fourth group of compounds was inactive and had, for the most part, one or two substituents with weak steric hindrance. In agreement with previous data for six lead compounds, this study suggests that, in these chemical series, a basic amino side-chain leads to interaction with phospholipid and the regulatory domain of PKC, whereas a 1,1-bis-(p-hydroxyphenyl) ethylene moiety leads to interaction with the catalytic domain of the enzyme.

A multivariate analysis of publication trends in the 1980s with special reference to South-East Asia

This study is a follow-up to a published correspondence Factor Analysis (CFA) of a dataset of over 6 million bibliometric entries. In the previous paper, CFA was used to show how the 48 most prolific countries stand in relation to each with regard to their publication interests in 17 specific disciplinary areas and one multidisciplinary field over the period 1981–1992. In this paper, we illustrate how the publication profiles of these 48 countries evolved over time during this period. We have (i) shown how analysis of the dataset highlights cutting edge versus ancient disciplines; (ii) identified the countries whose publication patterns underwent the most marked changes (e.g. the Asian dragons who chose to focus on engineering, materials sciences, computer sciences and molecular biology), and (iii) revealed the widespread attraction exerted by the publication pattern of the USA. There is, without doubt, an overall shift toward an Americanstyle pattern that may be a true reflection of research interests worldwide but that may also be explained by the hegemony of those who hold the reins of international publication.

World science in 18 disciplinary areas: Comparative evaluation of the publication patterns of 48 countries over the period 1981–1992

In order to be able to develop indicators that can measure the scientific and technological productivity of a nation, it is helpful to have at ones command a prior purely descriptive global overview of how various nations stand with respect to each other with regard to world science, i.e., to dispose of a framework for the elaboration of future quantitative studies.ISI has recently made available a highly comprehensive multidisciplinary database (over 6 million bibliometric entries from 1981 to 1992) that is founded on top-echelon journals and that can form the basis of such a framework. We have in the present study defined a publication pattern per nation that reflects its interest and potential in 18 disciplines and compared the publication patterns of 48 nations by descriptive multivariate analysis, i.e., by measuring the distance between nations in the n-dimensional system. Proximity is a sign of similarity, distance of diversity. Three multivariate methods of distance measurement were used: a hierarchical classification, the distance of each nation from the centre of gravity of the system calculated by χ2-metrics (typicality of behaviour), a bi-plot of the χ2-distances of 46 countries with respect to two reference countries that highlights clusters of nations with similar behaviour.The resultant plots are open to interpretation by experts. We conclude that three factors, geographical proximity, culture, and economic development are the principal determinants of the publication patterns of nations.

How to analyze publication time trends by correspondence factor analysis: analysis of publications by 48 countries in 18 disciplines over 12 years

This study is a follow‐up to a published Correspondence Factorial Analysis (CFA) of a dataset of over 6 million bibliometric entries (Dore et al. JASIS, 47(8), 588– 602,1996), which compared the publication output patterns of 48 countries in 18 disciplines over a 12‐year period (1981–1992). It analyzes by methods suitable for investigating short time series how these output patterns evolved over the 12‐year span. Three types of approach are described: (1) the chi2 distances of the publication output patterns from the center of gravity of the multidimensional system—which represents an average world pattern—were calculated for each country and for each year. We noted whether the patterns moved toward or away from the center with time; (2) individual annual output patterns were introduced as supplementary variables into an existing global overview covering the whole time‐span [CFA map of (countries × disciplines)]. We observed how these patterns moved about within the map year by year; (3) the matrix (disciplines × time) was analyzed by CFA to derive time trends for each country. CFA revealed the “inner clocks” governing publication trends. The time scale that best fitted the data was not a linear but an elastic scale. Although different countries laid emphasis on publication in different disciplines, the overall tendency was toward greater uniformity in publication patterns with time.

Analysis of the peripheral T‐cell repertoire in kidney transplant patients

The long‐term stability of renal grafts depends on the absence of chronic rejection. As T cells play a key role in rejection processes, analyzing the T‐cell repertoire may be useful for understanding graft function outcomes. We have therefore investigated the power of a new statistical tool, used to analyze the peripheral blood TCR repertoire, for determining immunological differences in a group of 229 stable renal transplant patients undergoing immunosuppression. Despite selecting the patients according to stringent criteria, the patients displayed heterogeneous T‐cell repertoire usage, ranging from unbiased to highly selected TCR repertoires; a skewed TCR repertoire correlating with an increase in the CD8+/CD4+ T‐cell ratio. T‐cell repertoire patterns were compared in patients with clinically opposing outcomes i.e. stable drug‐free operationally tolerant recipients and patients with the “suspicious” form of humoral chronic rejection and were found significantly different, from polyclonal to highly selected TCR repertoires, respectively. Moreover, a selected TCR repertoire was found to positively correlate with the Banff score grade. Collectively, these data suggest that TCR repertoire categorization might be included in the calculation of a composite score for the follow‐up of patients after kidney transplantation.

Multivariate analysis of the correlation between noctuidae subfamilies and the chemical structure of their sex pheromones or male attractants

Female-emitted pheromones and sex attractants of Noctuidae were investigated using a specific computer procedure to analyze data collected from the literature. Correspondence analysis was used to survey the structure-activity relationships of sex pheromones in seven subfamilies. Structural, stereochemical, and functional features of active molecules were related to taxonomy. This multidimensional analysis revealed that the prevalent chemical frame of noctuid moth pheromones was a monounsaturated acetate withZ stereochemistry and a double bond on the fifth carbon closest to the nonfunctional branch of the molecule. Possible phylogenetic relationships within Noctuidae and between Noctuidae and other families are discussed in light of the sex pheromone biochemistry. Female sex pheromones appeared to be an additional character to be considered in the classification of noctuid moths.