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PubMed1991

Level and form of psychopathology and the structure of group therapy.

Drawing upon concepts derived from ego psychological and object relations psychoanalytic theories of individual development and from a depth group psychology, the present empirical study, a naturalistic field investigation, explored hypothesized relationships between aspects of patients' psychological boundaries and structural features of inpatient therapy groups. More specifically, patients were assessed in terms of their level (i.e., psychotic vs. borderline organization) and form (i.e., anaclitic vs. introjective) of psychopathology. Their perceptions of themselves and of their therapy groups were measured following participation in two kinds of small group treatment designed to differ in terms of degree of internal structuring. Findings, generally supporting the hypotheses, showed the anaclitic borderline patients, in particular, to be most sensitive to structural variations and most adversely affected by an impersonal and highly structured treatment climate. Theoretical and practical implications of these findings were discussed.

Adult↗
PubMed2006

Synthesis of 1-deoxysphingosine derivatives with conformationally restricted pyrrolidinediol head groups.

[structure: see text] A family of cyclic 1-deoxysphingolipid derivatives of structure 4 has been designed and synthesized, which may serve as tumorigenesis suppressors for various cancers. Compound 4 is a second-generation analogue developed from sphingosine (1), in which a hydroxyl substituent is moved from C1 to C5 and a methylene is added for conformational rigidity between the C2-nitrogen substituent and C4. The synthetic chemistry for pyrrolidine ring closure at C3-C4 features ring-closing metathesis followed by hydroboration-oxidation.

Cyclization↗
PubMed2006

Dramatic enhancement of enantioselectivity of biotransformations of beta-hydroxy nitriles using a simple O-benzyl protection/docking group.

[Structure: see text] Catalyzed by the Rhodococcus erythropolis AJ270 whole cell catalyst, the O-benzylated beta-hydroxy alkanenitriles underwent remarkably high enantioselective biotransformations, whereas the biotransformations of free beta-hydroxy alkanenitriles gave very low enantioselectivity. The easy manipulations of O-protection and O-deprotection, excellent chemical and enantiomeric yields of biotransformations, along with the scalability render this enzymatic transformation attractive and practical for the synthesis of highly enantiopure beta-hydroxy alkanoic acids and their amide derivatives.

Amides↗
PubMed2004

Fast iterative gene clustering based on information theoretic criteria for selecting the cluster structure.

Grouping of genes into clusters according to their expression levels is important for deriving biological information, e.g., on gene functions based on microarray and other related analyses. The paper introduces the selection of the number of clusters based on the minimum description length (MDL) principle for the selection of the number of clusters in gene expression data. The main feature of the new method is the ability to evaluate in a fast way the number of clusters according to the sound MDL principle, without exhaustive evaluations over all possible partitions of the gene set. The estimation method can be used in conjunction with various clustering algorithms. A recent clustering algorithm using principal component analysis, the "gene shaving" (GS) procedure, can be modified to make use of the new MDL estimation method, replacing the Gap statistics originally used in GS algorithm. The resulting clustering algorithm is shown to perform better than GS-Gap and CEM (classification expectation maximization), in the simulations using artificial data. The proposed method is applied to B-cell differentiation data, and the resulting clusters are compared with those found by self-organizing maps (SOM).

Algorithms↗
PubMed1985

Induction by paracetamol of bladder and liver tumours in the rat. Effects on hepatocyte fine structure.

Groups of male and female inbred Leeds strain rats were fed diets containing either 0.5% or 1.0% paracetamol by weight for up to 18 months. At the 1.0% dosage level, 20% of rats of both sexes developed neoplastic nodules of the liver, a statistically significant incidence. These rats also showed gross enlargement of their livers and an increase in foci of cellular alteration, the latter also being observed in the low dosage male rats. Papillomas of the transitional epithelium of the bladder developed in all paracetamol-treated groups, and three rats bore bladder carcinomas. However, significant yields of bladder tumours were only obtained from low dosage females and high dosage males. Additionally, 20 to 25% of paracetamol-treated rats developed hyperplasia of the bladder epithelium, which was not coincident with the presence of bladder calculi. A low yield of tumours at various other sites also arose following paracetamol feeding. An electron microscope study of the livers of paracetamol-treated rats revealed ultrastructural changes in the hepatocytes that resemble those that result from exposure to a variety of known hepatocarcinogens.

Acetaminophen↗
PubMed1991

Comparative study of the hypotensive effect of a group of structural derivatives of glaucine.

A comparative study was made on the hypotensive effect of a group of dehydrogenated structural derivatives of the alkaloid glaucine. The compounds studied induced a slowly occurring marked decrease in the blood pressure. Applied intravenously, they did not manifest the initial brief and very pronounced phase of the hypotensive effect, typical of glaucine, and failed to change substantially the respiration and the cardiac activity of the experimental animals. The most marked hypotensive effect was demonstrated by 7-benzoyl-dehydroglaucine (DG4), which reduced the blood pressure by about 50 and 60% respectively, when applied in doses of 1 mg/kg and 2.5 mg/kg. Applied duodenally, the dehydrogenated glaucine derivatives also manifested a gradually occurring hypotensive effect, whereby DG4 again caused the most pronounced blood pressure drop. Depending on the DG4 and glaucine doses used, the pressor effects of noradrenaline (NA) and nicotine (NIC) were moderately to strongly suppressed or completely inhibited. In experiments on cat membrana nictitans glaucine also suppressed moderately (2.5 mg/kg) or markedly (5 mg/kg) the contractile effects of NIC and NA, while DG4 did not influence (1 mg/kg) or potentiated (2.5 mg/kg) these effects.

Animals↗
PubMed2000

Relatedness in trait group models of social evolution.

Genetic relatedness is a central concept in the study of social evolution. Though originally defined in terms of genealogy, the modern version of relatedness accommodates genetic similarity of any origin. This paper examines relatedness in group structured modes, in which a trait affects the fitness of all group members. Such traits can be divided into two types, based on whether their group fitness effects encompass all group members including the actor ("whole-group traits"), or only group members other than the actor ("other-only traits"). Both trait types are common in nature as well as in theoretical models, but they have rarely been distinguished clearly. The average relatedness of recipients to actors differs for the two trait types within the same population and even the same individual, leading to different selection pressures and evolutionary outcomes. Total relatedness in group-structured models can be partitioned into two components: structural relatedness due to the size and number of groups in the population, and assortative relatedness due to the distribution of genotypes among groups. Each component differs for whole-group vs. other-only traits, both in terms of their values and the factors that influence them. Some key differences include: positive relatedness requires positive assortment for other-only but not for whole-group traits; negative relatedness is possible for other-only but not whole-group traits; relatedness depends on average group size for whole-group but not other-only traits, and non-random assortment into groups affects relatedness more strongly for other-only than whole-group traits. Recognizing the distinction between these trait types resolves some apparent contradictions in the literature, and clarifies the limits of some previous results.

Animals↗
PubMed1999

Global, voxel, and cluster tests, by theory and permutation, for a difference between two groups of structural MR images of the brain.

We describe almost entirely automated procedures for estimation of global, voxel, and cluster-level statistics to test the null hypothesis of zero neuroanatomical difference between two groups of structural magnetic resonance imaging (MRI) data. Theoretical distributions under the null hypothesis are available for 1) global tissue class volumes; 2) standardized linear model [analysis of variance (ANOVA and ANCOVA)] coefficients estimated at each voxel; and 3) an area of spatially connected clusters generated by applying an arbitrary threshold to a two-dimensional (2-D) map of normal statistics at voxel level. We describe novel methods for economically ascertaining probability distributions under the null hypothesis, with fewer assumptions, by permutation of the observed data. Nominal Type I error control by permutation testing is generally excellent; whereas theoretical distributions may be over conservative. Permutation has the additional advantage that it can be used to test any statistic of interest, such as the sum of suprathreshold voxel statistics in a cluster (or cluster mass), regardless of its theoretical tractability under the null hypothesis. These issues are illustrated by application to MRI data acquired from 18 adolescents with hyperkinetic disorder and 16 control subjects matched for age and gender.

Adolescent↗
PubMed2001

Cloning of rainbow trout egg envelope proteins: members of a unique group of structural proteins.

All vertebrate eggs are surrounded by an extracellular envelope that protects the egg and is vital for a successful fertilization. The terminology and functions of the egg envelope vary in different vertebrate groups, but the envelope itself is consistently composed of a few major proteins that are deposited around the oocyte during oocyte growth. Here, we describe the deduced amino acid sequences and tissue expression patterns of the three major egg envelope proteins for rainbow trout (Oncorhynchus mykiss). All three vitelline envelope proteins (VEPs) are expressed in the livers of both male and female fish, with higher expression in females. In addition, VEPgamma mRNA is also detected in the female gonads. To our knowledge, this is the first time that expression of a VEP protein gene has been demonstrated to occur in more than one organ. Sequence comparison reveals that all three VEP proteins share distinct homology with their amphibian, avian, and mammalian counterparts. Whereas mammalian zona pellucida protein 3 isoforms contain two conserved serines needed for sperm binding, these are not conserved in teleost species, in which sperm entry is restricted to the micropyle. Besides the difference in VEPgamma sperm-binding function, the high sequence homology suggests that the egg envelope proteins from these distinct vertebrate groups share a common ancestry and form a unique group of structural proteins.

Amino Acid Sequence↗
PubMed1999

Effect of the labeling group in structural analyses of malononitrile-labeled oligosaccharides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and electrospray ionization mass spectrometry

Structural analyses of oligosaccharide-malononitrile derivatives were conducted by matrix-assisted laser desorption/ionization post-source decay (MALDI-PSD) analysis in positive ion mode, and by electrospray ionization collision-induced dissociation (ESI-CID) analysis in negative ion mode. The malononitrile derivatives of oligosaccharides, which were developed for separation and detection of multi-component oligosaccharides by negative ion electrospray ionization mass spectrometry (ESI-MS), were detected by positive ion MALDI with a detection limit at a 400 fmol level even without any purification procedure for the derivatized oligosaccharide mixture. The results of structural analyses of oligosaccharide-malononitrile derivatives by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) were affected drastically by the choice of matrix used, and gave much more structural information than the free oligosaccharide. The effects of the malononitrile labeling group on the structural analyses of oligosaccharide-malononitrile derivatives by positive-ion MALDI-PSD analysis in reflectron mode, and by MALDI time-of-flight mass spectrometry (MALDI-TOFMS) in linear mode, are compared with those of in-source ESI-CID analysis in negative ion mode. The malononitrile derivatization method could be a powerful tool for structural analyses of oligosaccharides. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2003

High-pressure structural trends of Group 15 elements: simple packed structures versus complex host-guest arrangements.

The Group 15 elements P, As, Sb, and Bi all have layered structures consisting of six-membered rings under ambient conditions and attain the body-centered cubic (bcc) structure at the highest pressures applied. In the intermediate pressure region, however, phosphorus and its heavier congeners behave profoundly differently. In this region P first attains the open packed simple cubic (sc) structure for a wide range of pressures and then transforms into the rarely observed simple hexagonal (sh) structure. For the heavier congeners complex, incommensurately modulated host-guest structures emerge as intermediate pressure structures. We investigated the high-pressure behavior of P and As by ab initio density functional calculations in which pseudopotentials and a plane wave basis set were employed. The incommensurately modulated high-pressure structure of As was approximated by a supercell. Our calculations reproduced the experimentally established pressure stability ranges of the sc and sh structures for P and the host-guest structure for As very well. We found that the sc and especially the sh structure are decisively stabilized by the admixture of d states in the occupied levels of the electronic structure. This admixture releases s-s antibonding states above the Fermi level (s-d mixing). With pressure, s-d mixing increases rapidly for P, whereas it remains at a low level for As. As a consequence, the band energy contribution to the total energy determines the structural stability for P in the intermediate pressure region, giving rise to simple packed structures. On the other hand, in the intermediate pressure region of the heavier Group 15 elements, a delicate interplay between the electrostatic Madelung energy and the band energy leads to the formation of complex structures.

Journal Article↗
PubMed2003

Optimization of individual and population designs using Splus.

We address the problem of design optimization for individual and population pharmacokinetic studies. We develop Splus generic functions for pharmacokinetic design optimization: IFIM, a function for individual design optimization similar to the ADAPT II software, and PFIM_OPT, a function for population design optimization which is an extension of the Splus function PFIM for population design evaluation. Both evaluate and optimise designs using the Simplex algorithm. IFIM optimizes the sampling times in continuous intervals of times; PFIM_OPT optimizes either, for a given group structure of the population design, only the sampling times taken in some given continuous intervals or, both the sampling times and the group structure, performing then statistical optimization. A combined variance error model can be supplied with the possibility to include parameters of the error model as parameters to be estimated. The performance of the optimization with the Simplex algorithm is demonstrated with two pharmacokinetic examples: by comparison of the optimized designs to those of the ADAPT II software for IFIM, and to those obtained using a grid search or the Fedorov-Wynn algorithm for PFIM_OPT. The influence of the variance error model on design optimization was investigated. For a given total number of samples, different group structures of a population design are compared, showing their influence on the population design efficiency. The functions IFIM and PFIM_OPT offer new efficient solutions for the increasingly important task of optimization of individual or population pharmacokinetic designs.

Algorithms↗
PubMed1996

1H, 15N and 13C resonance assignments and secondary structure of group II phospholipase A2 from Agkistrodon piscivorus piscivorus: presence of an amino-terminal helix in solution.

1H, 15N and 13C resonance assignments are presented for the group II phospholipase A2 (PLA2) from Agkistrodon piscivorus piscivorus. The secondary structure of the enzyme has been inferred from an analysis of coupling constants, interproton distances, chemical shifts, and kinetics of amide exchange. Overall, the secondary structure of this PLA2 is similar to the crystal structure of the homologous group II human nonpancreatic secretory phospholipase [Scott, D.L., White, S.P., Browning, J.L., Rosa, J.J., Gelb, M.H. and Sigler, P.B. (1991) Science, 254, 1007-1010]. In the group I enzyme from porcine pancreas, the amino-terminal helix becomes fully ordered in the ternary complex of enzyme, lipid micelles and inhibitor. The formation of this helix is thought to be important for the increase in activity of phospholipases on aggregated substrates [Van den Berg, B., Tessari, M., Boelens, R., Dijkman, R., De Haas, G. H., Kaptein, R. and Verheij, H.M. (1995) Nature Strct. Biol., 2, 402-406]. However, the group II enzyme from Agkistrodon piscivorus piscivorus possesses a defined and well-positioned amino-terminal helix in the absence of substrate. Therefore, there is a clear difference between the conformation group I and group II enzymes in solution. These conformational differences suggest that formation of the amino-terminal helix is a necessary, but not sufficient, step in interfacial activation of phospholipases.

Amino Acid Sequence↗
PubMed1994

Discrimination of auditory temporal patterns.

Two same-different discrimination experiments were performed for click patterns having a total duration of about 4 sec and interclick intervals of n x 250 msec, with n a random integer. In Experiment 1, the influence of the physical click group structure on discrimination performance was investigated. In Experiment 2, the effect of the strength of an induced internal clock on discrimination performance was measured. Performance was poor if the group structure of clicks was maintained during a change in click pattern and also if the induced internal clock strength was low. The performance of about 70% of the subjects improved significantly if either a change in click grouping structure occurred or a strong internal clock could be induced. These results cannot be accounted for with simple models based on single-interval duration discrimination or between-pattern correlation statistics.

Attention↗
PubMed1994

Representation of the secondary and tertiary structure of group I introns.

Group I introns, which are widespread in nature, carry out RNA self-splicing. The secondary structure common to these introns was for the most part established a decade ago. Information about their higher order structure has been derived from a range of experimental approaches, comparative sequence analysis, and molecular modelling. This information now provides the basis for a new two-dimensional structural diagram that more accurately represents the domain organization and orientation of helices within the intron, the coaxial stacking of certain helices, and the proximity of key nucleotides in three-dimensional space. It is hoped that this format will facilitate the detailed comparison of group I intron structures.

Anabaena↗
PubMed1996

Construction and analysis of a profile library characterizing groups of structurally known proteins.

A new sequence motif library StrProf was constructed characterizing the groups of related proteins in the PDB three-dimensional structure database. For a representative member of each protein family, which was identified by cross-referencing the PDB with the PIR superfamily classification, a group of related sequences was collected by the BLAST search against the nonredundant protein sequence database. For every group, the motifs were identified automatically according to the criteria of conservation and uniqueness of pentapeptide patterns and with a dual dynamic programming algorithm. In the StrProf library, motifs are represented by profile matrices rather than consensus patterns to allow more flexible search capabilities. Another dynamic programming algorithm was then developed to search this motif library. When the computationally derived StrProf was compared with PROSITE, which is a manually derived motif library in the best consensus pattern representation, the numbers of identified patterns were comparable. StrProf missed about one third of the PROSITE motifs, but there were also new motifs lacking in PROSITE. The new library was incorporated in SMART (Sequence Motif Analysis and Retrieval Tool), a computer tool designed to help search and annotate biologically important sites in an unknown protein sequence. The client program is available free of charge through the Internet.

Algorithms↗
PubMed2006

[Effectiveness of ability grouping in structured fall prevention exercise program for frail elderly people].

AIM: To assess the effectiveness of ability grouping in a fall prevention structured exercise program for elderly people. METHODS: We enrolled 124 subjects from among 2,582 elderly people aged 70 to 84 years living in the Tsurugaya district in Sendai City. Exclusion criteria were 1) motor fitness scale (MFS) score 9 points or more, 2) severe sensory, cognitive, or 3) physical disorders, and 4) nursing care grade 2 or more. Those ranked in the lower fourth and in the upper 3 fourths of the timed up and go test (TUGT) were each randomly assigned to 3 groups. Subjects in groups A and B had an exercise program for lower and higher fitness subjects separately, whereas all subjects in group C underwent a single exercise program. The exercise program, once a week for 12 weeks, consisted of strength and stability training. TUGT, lateral reach (LR), leg power per body weight and MFS were measured after the intervention and compared with the baseline values. RESULTS: There were no difference in the baseline characteristics among the groups. For group A, no significant changes in physical fitness measures, for group B a small but significant deterioration in LR, and for group C a small but significant deterioration in LR and TUGT were observed. MFS score improved significantly in all groups. CONCLUSION: Ability grouping appeared to be effective for a short-term exercise program in maintaining the physical ability, but the effectiveness did not reach statistical significance in the randomized controlled design.

Accidental Falls↗