Showing papers by "University of Grenoble published in 1993"

Detection of complete and partial chromosome gains and losses by comparative genomic in situ hybridization

Abstract: Comparative genomic in situ hybridization (CGH) provides a new possibility for searching genomes for imbalanced genetic material. Labeled genomic test DNA, prepared from clinical or tumor specimens, is mixed with differently labeled control DNA prepared from cells with normal chromosome complements. The mixed probe is used for chromosomal in situ suppression (CISS) hybridization to normal metaphase spreads (CGH-metaphase spreads). Hybridized test and control DNA sequences are detected via different fluorochromes, e.g., fluorescein isothiocyanate (FITC) and tetraethylrhodamine isothiocyanate (TRITC). The ratios of FITC/TRITC fluorescence intensities for each chromosome or chromosome segment should then reflect its relative copy number in the test genome compared with the control genome, e.g., 0.5 for monosomies, 1 for disomies, 1.5 for trisomies, etc. Initially, model experiments were designed to test the accuracy of fluorescence ratio measurements on single chromosomes. DNAs from up to five human chromosome-specific plasmid libraries were labeled with biotin and digoxigenin in different hapten proportions. Probe mixtures were used for CISS hybridization to normal human metaphase spreads and detected with FITC and TRITC. An epifluorescence microscope equipped with a cooled charge coupled device (CCD) camera was used for image acquisition. Procedures for fluorescence ratio measurements were developed on the basis of commercial image analysis software. For hapten ratios 4/1, 1/1 and 1/4, fluorescence ratio values measured for individual chromosomes could be used as a single reliable parameter for chromosome identification. Our findings indicate (1) a tight correlation of fluorescence ratio values with hapten ratios, and (2) the potential of fluorescence ratio measurements for multiple color chromosome painting. Subsequently, genomic test DNAs, prepared from a patient with Down syndrome, from blood of a patient with Tcell prolymphocytic leukemia, and from cultured cells of a renal papillary carcinoma cell line, were applied in CGH experiments. As expected, significant differences in the fluorescence ratios could be measured for chromosome types present in different copy numbers in these test genomes, including a trisomy of chromosome 21, the smallest autosome of the human complement. In addition, chromosome material involved in partial gains and losses of the different tumors could be mapped to their normal chromosome counterparts in CGH-metaphase spreads. An alternative and simpler evaluation procedure based on visual inspection of CCD images of CGH-metaphase spreads also yielded consistent results from several independent observers. Pitfalls, methodological improvements, and potential applications of CGH analyses are discussed.

Monge-Ampère Operators, Lelong Numbers and Intersection Theory

Abstract: This chapter is a survey article on the theory of Lelong numbers, viewed as a tool for studying intersection theory by complex differential geometry. We have not attempted to make an exhaustive compilation of the existing literature on the subject, nor to present a complete account of the state-of-the-art. Instead, we have tried to present a coherent unifying frame for the most basic results of the theory, based in part on our earlier works [7–10] and on Siu’s fundamental work [30]. To a large extent, the asserted results are given with complete proofs, many of them substantially shorter and simpler than their original counterparts. We only assume that the reader has some familiarity with differential calculus on complex manifolds and with the elementary facts concerning analytic sets and plurisubharmonic functions. The reader can consult Lelong’s books [25, 26] for an introduction to the subject. Most of our results still work on arbitrary complex analytic spaces, provided that suitable definitions are given for currents, plurisubharmonic functions, etc., in this more general situation. We have refrained ourselves from doing so for simplicity of exposition; we refer the reader to Ref. 9 for the technical definitions required in the context of analytic spaces.

The atmospheric CH4 increase since the Last Glacial Maximum. I - Source estimates

Abstract: An estimate of the distribution of wetland area and associated CH4 emission is presented for the Last Glacial Maximum (LGM, 18 kyr BP, kiloyear Before Present) and the Pre-Industrial Holocene (PIH, 9000-200 years BP) The wetland source, combined with estimates of the other biogenic sources and sink, yields total source strengths of 120 and 180 Tg CH4/yr for LGM and PIH respectively These source strengths are shown to be consistent with source estimates inferred from a photochemical model, and point to changes in wetland CH4 source as a major factor driving the atmospheric CH4 increase from LGM to PIH

Stable properties of plethysm : on two conjectures of Foulkes

Abstract: Two conjectures made by II.O. Foulkes in 1950 can be stated as follows. 1) Denote byV a finite-dimensional complex vector space, and byS m V itsm-th symmetric power. Then the GL(V)-moduleS n (S m V ) contains the GL(V)-moduleS n (S m V ) forn > m. 2) For any (decreasing) partition λ = (λ1,λ2,λ3,...), denote byS λ V the associated simple, polynomial GL(V)-module. Then the multiplicity of\(S_{(\lambda _1 + np,\lambda _2 \lambda _{3,...} )} V\) in the GL(V)-moduleS n (S m+p Y) is an increasing function ofp. We show that Foulkes' first conjecture holds forn large enough with respect tom (Corollary 1.3). Moreover, we state and prove two broad generalizations of Foulkes' second conjecture. They hold in the framework of representations of connected reductive groups, and they lead e.g. to a general analog of Hermite's reciprocity law (Corollary 1 in 3.3).

Cation adsorption on oxides and clays: The aluminum case

Abstract: The sorption mechanisms for trace metal ions on montmorillonite have been investigated. Complexation with surface hydroxyl groups located on the brocken edges of platelet particles is found to occur over a pH range similar to that observed on silica and other oxides, at comparable metal/site ratios. A second mechanism involving cation exchange on the negatively charge basal plane, which does not involve proton exchange in our experimental conditions, has been invoked to explain the low pH behavior. Consistent with this cation exchange mechanism, adsorption at low pH is strongly ionic strength dependant. A quantitative model which involves both mechanisms is presented and tested against both cation and proton adsorption data.

Hill-climbing, simulated annealing and genetic algorithms: a comparative study and application to the mapping problem

Abstract: Hill-climbing, simulated annealing and genetic algorithms are search techniques that can be applied to most combinatorial optimization problems. The three algorithms are used to solve the mapping problem, which is the optimal static allocation of communication processes on distributed memory architectures. Each algorithm is independently evaluated and optimized according to its parameters. The parallelization of the algorithms is also considered. As an example, a massively parallel genetic algorithm is proposed for the problem, and results of its implementation on a 128-processor Supernode are given. A comparative study of the algorithms is then carried out. The criteria of performance considered are the quality of the solutions obtained and the amount of search time used for several benchmarks. A hybrid approach consisting of a combination of genetic algorithms and hill-climbing is also proposed and evaluated. >

Effects of the cold pressor test on short-term fluctuations of finger arterial blood pressure and heart rate in normal subjects.

Abstract: The effect of the cold pressor test on autonomic cardiovascular control was studied non-invasively by means of spectrum analysis of periodic heart rate and blood pressure fluctuations in ten normal subjects. Fast Fourier Transform algorithm based on a 256-point time series (sampling rate 2 Hz, i.e. 2-min and 8-s) was used to estimate the amplitude spectra of heart rate and blood pressure rhythmicity at the low frequency (70–140 mHz) and respiration related frequency (230–270 mHz) band. Respiration rate was controlled at 250 mHz. Auto- and cross-spectral techniques were used to determine the complex relationship between systolic blood pressure and heart rate fluctuations in the frequency domain. The spectral pattern of systolic and diastolic blood pressure showed a marked increment of the absolute and relative (100 multiplied with absolute value/total area under the curve of the amplitude spectrum from 15–500 mHz) low frequency component: control vs. cold pressor test—systolic blood pressure—absolute values (in [mmHg/Hz1/2]): 634.4 ± 48.9 vs. 827.4 ± 69.9* relative values (in [%]): 26 ± 2 vs. 32 ± 2*; diastolic blood pressure —absolute values: 433.2 ± 42.3 vs. 537.2 ± 45.8* relative values: 35 ± 3 vs. 40 ± 2*, (average ± SEM, *P < 0.05). The cold pressor test induced no change in average heart rate; the absolute low frequency component in heart rate spectra increased clearly during the test: low frequency component (in [bpm/Hz1/2]): 586.9 ± 89.9 vs. 712.0 ± 91.4*, while the relative low frequency component did not change: 29 ± 3 vs. 30 ± 3. There was no alteration in the respiration related frequency component in all time series and in the transfer gain and phase functions during cold pressor test. We conclude that the cold pressor test increases low frequency systolic blood pressure fluctuations which reflects an increase in sympathetic vasomotor control. Furthermore the cold pressor test does not induce change in the transfer gain and phase characteristics of modulation of heart rate by systolic blood pressure.

Fast and easy interpretation of a set of absorption spectra: theory and qualitative applications for UV examination of waters and wastewaters

Abstract: The isosbestic point of a set of absorption spectra is often the only sign for the simple interpretation of a phenomenon: the presence of two components or eventually two mixtures with a fixed relation between their concentrations. Unfortunately explanations in the literature are not complete so that they can lead the chemist to wrong interpretations. This work presents an exhaustive theory for the interpretation of the existence of one or several isosbestic points and secondly proposes a much more general method to find relevant informations among a lot of absorption spectra: this method based on the rank determination of the data matrix is simple and fast and allows to find the independent spectra from which all the others can be computed by a linear combination. So, the number and the nature of the spectra of the reference components — or mixture — of all the samples can easily be known. Some qualitative applications for UV examination of natural waters and wastewaters are presented to show the importance of the proposed method and the similarity between the reference spectra of waters of different nature.

Transplantation Et Isospectralité II

Abstract: © Séminaire de Théorie spectrale et géométrie (Chambéry-Grenoble), 1990-1991, tous droits réservés. L’accès aux archives de la revue « Séminaire de Théorie spectrale et géométrie » implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/legal.php). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright.

Improved Noninvasive Diagnostic Testing for Malignant Hyperthermia Susceptibility from a Combination of Metabolites Determined In Vivo with 31P-Magnetic Resonance Spectroscopy

Abstract: Background Phosphorus magnetic resonance spectroscopy (31P-MRS) in vivo has been suggested recently as a possible noninvasive diagnostic test in malignant hyperthermia (MH) susceptibility. However, differences between protocols and also within subjects may have led to inconsistent MRS abnormalities reported during and after exercise. The aim of the current study was to detect discriminant abnormalities in the leg muscles using in vivo 31P-MRS during the rest period. Methods Fourteen patients shown to be MH-susceptible and 22 patients MH-negative on the basis of in vitro caffeine/halothane contracture tests according to the European MH group protocol were compared to 36 control subjects using in vivo 31P-MRS during the rest period. A score of MRS combined abnormalities was calculated from a stepwise discriminant function analysis. Results The MH-susceptible group had a significantly (P or = 1.65). The sensitivity and specificity of this threshold value were 93 and 95%, respectively. Conclusions This study confirms that 31P-MRS could be useful for distinguishing noninvasively between MH-susceptible and MH-negative patients if several MRS parameter are combined. Moreover, the present MRS approach appears to be more reliable and easier than that used during exercise.

Immediate rearrangements of human sperm chromosomes following in-vivo irradiation

Abstract: The short-term effects of radiotherapy on sperm chromosomes was evaluated in two Hodgkin patients. Sperm cytogenetics were analysed by using human-hamster cross-fertilization. Immediately after irradiation, most sperm metaphases from the first patient exhibited multiple rearrangements, whereas in the second one, the incidence of such abnormalities was only slightly increased. Multi-fragmented chromosomes and structural aberrations of the chromatid-type were observed, suggesting a specific immediate response.

A measurement of D meson production in Z 0 hadronic decays

Abstract: A study of the fragmentation properties of charm and bottom quarks intoD mesons is presented. From 263 700Z 0 hadronic decays collected in 1991 with the DELPHI detector at the LEP collider,D 0,D + andD *+ are reconstructed in the modesK − π +,K − π + K + andD 0 π + followed byD 0→K − π +, respectively. The fractional decay widths $$\Gamma {{(Z^0 \to {D \mathord{\left/ {\vphantom {D {\bar D}}} \right. \kern- ulldelimiterspace} {\bar D}}X)} \mathord{\left/ {\vphantom {{(Z^0 \to {D \mathord{\left/ {\vphantom {D {\bar D}}} \right. \kern- ulldelimiterspace} {\bar D}}X)} {\Gamma _h }}} \right. \kern- ulldelimiterspace} {\Gamma _h }}$$ are determined, and first results are presented for the production ofD mesons from $$c\bar c$$ and $$b\bar b$$ events separately. The average energy fraction ofD *± in charm quark fragmentation is found to be 〈X E (D *)〉 c =0.487±0.015 (stat)±0.005 (sys.). Assuming that the fraction ofD s and charm-baryons produced at LEP is similar to that around 10 GeV, theZ 0 partial width into charm quark pairs is determined to beΓ c /Γ h =0.187±0.031 (stat)±0.023 (sys). The probability for ab quark to fragment into $$\bar B_s $$ orb-baryons is inferred to be 0.268±0.094 (stat)±0.100 (sys) from the measured probability that it fragments into a $$\bar B^0 $$ orB −.

The six genes of the Rubisco small subunit multigene family from Mesembryanthemum crystallinum, a facultative CAM plant

Abstract: The nucleotide sequences of the entire gene family, comprising six genes, that encodes the Rubisco small subunit (rbcS) multigene family in Mesembryanthemum crystallinum (common ice plant), were determined. Five of the genes are arranged in a tandem array spanning 20 kb, while the sixth gene is not closely linked to this array. The mature small subunit coding regions are highly conserved and encode four distinct polypeptides of equal lengths with up to five amino acid differences distinguishing individual genes. The transit peptide coding regions are more divergent in both amino acid sequence and length, encoding five distinct peptide sequences that range from 55 to 61 amino acids in length. Each of the genes has two introns located at conserved sites within the mature peptide-coding regions. The first introns are diverse in sequence and length ranging from 122 by to 1092 bp. Five of the six second introns are highly conserved in sequence and length. Two genes, rbcS-4 and rbcS-5, are identical at the nucleotide level starting from 121 by upstream of the ATG initiation codon to 9 by downstream of the stop codon including the sequences of both introns, indicating recent gene duplication and/or gene conversion. Functionally important regulatory elements identified in rbcS promoters of other species are absent from the upstream regions of all but one of the ice plant rbcS genes. Relative expression levels were determined for the rbcS genes and indicate that they are differentially expressed in leaves.

Reproducibility of motor effects induced by successive subcutaneous apomorphine injections in Parkinson's disease.

Abstract: We performed a crossover study of apomorphine-induced motor response reproducibility in 10 parkinsonian patients with the ''on-off'' phenomenon. On 2 separate days, each patient received two successive identical s.c. apomorphine injections, the second injection being randomly administered either 10 or 80 min after the end of the first apomorphine-induced motor benefit. Latency (12.3 +/- 4.5 min) and duration (61.9 +/- 13.3 min) of motor effects were similar in all tests. A transient worsening of the parkinsonian state after a motor improvement induced by apomorphine occurred in most of the patients. Therefore, the duration and severity of the ''off'' period after a motor improvement does not seem to influence the efficacy of a second apomorphine administration.

Measurement of the Triple-Gluon Vertex from 4-Jet Events at LEP

Abstract: From the combined data of 1990 and 1991 of the DELPHI experiment at LEP, 13057 4-jet events are obtained and used for determining the contribution of the triple-gluon vertex. The relevant variables are the generalized Nachtmann Reiter angle θNR* and the opening angle of the two least energetic jets. A fit to their two-dimensional distribution yields $$C_A /C_F = 2.12 \pm 0.35 and N_C /N_A = 0.46 \pm 0.19,$$ whereCA/CF is the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung from quarks, andNC/NA, the ratio of the number of quark colours to the number of gluons.

Higher Order Correlation Coefficients

Abstract: We study the higher order correlation coefficients. These coefficients complement the classical correlation coefficient by measuring some dependences more and more sharply. We prove that they can detect the existence of functional dependence of type g(X) = g′(Y). We obtain the asymptotic distribution of higher order empirical correlation coefficients. We deduce an Hilbertian Independence test.

Bootstrapping the change-point of a hazard rate

Abstract: This paper concerns the asymptotic validity of the bootstrap method in a non-regular model. Specifically, it is shown that the parametric bootstrap of the change-point parameter in the change-point hazard rate model works.

External and implanted pumps for apomorphine infusion in parkinsonism

Abstract: Continuous delivery of dopaminergic agents to the striatum is a major challenge to improve the treatment of Parkinson’s disease. Apomorphine is one of the best candidates because of its solubility and its D1 and D2 receptor agonist properties.

Catastrophe theory and its critics

Abstract: Catastrophe theory has been sharply criticized because it does not seem to have practical applications nor does it seem to allow us to increase our power over Nature. I want to ‘rehabilitate’ the theory by foregoing the controversy raised by scientists about its practical efficiency. After a short exposition of the theory's mathematical formalism and a detailed analysis of the main objections that have been raised against it, I argue that theory is not only to be judged on its practical ‘results’, which are in fact limited, but also on its epistemological and philosophical implications. Catastrophe theory indeed represents a real revolution in science: it announces the coming of a more theoretical, less practical, science, having more to do with understanding reality than with acting on it, and, from that point of view, it may be considered as the modern philosophy of Nature.