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PubMedDate not supplied

Analytical mass spectrometry of herbicides.

Herbicides are chemical substances that are applied to agricultural soils, gardens, lawns, or plants to destroy or to prevent the growth of undesirable vegetation. The herbicides included in this review are generally synthetic organic compounds that are ingredients in commercial herbicide products that were designated active during late 2002 in the U.S. Environmental Protection Agency's database of registered and canceled pesticide products. The compounds are organized into 21 categories according to their general chemical structures or a common structural group. The herbicides in each category are discussed in terms of their structures, their database electron ionization mass spectra, and their amenability to separation and measurement with gas chromatography, reversed-phase liquid chromatography, and capillary electrophoresis combined with mass spectrometry. Ionization techniques that are considered here are mainly electron ionization, electrospray, and atmospheric pressure chemical ionization. Sixty-six references are provided to herbicide reviews, and to the recent herbicide analytical chemistry and mass spectrometry research literature.

Databases, Factual↗
PubMed1998

Characterization of a mouse monoclonal IgG3 antibody to the tumor-associated globo H structure produced by immunization with a synthetic glycoconjugate.

Globo H (Fuc alpha1 --> 2Galbeta1 --> 3GalNAcbeta1 --> 3Gal alpha1 --> 4Galbeta1 --> 4Glc) is a carbohydrate structure that shows enhanced expression in many human carcinomas. From mice immunized with a globo H-KLH (keyhole limpet hemocyanin) synthetic conjugate an IgG3 monoclonal antibody (mAb VK-9) was derived that recognizes the globo H structure. Serological analysis showed that the minimal structure recognized by this mAb was the tetrasaccharide sequence Fuc alpha1 --> 2Galbeta1 --> 3GalNAcbeta1 --> 3Gal. An isomeric structure with an internal alphaGalNAc linkage was also recognized but less efficiently. mAb VK-9 did not react with many related structures, such as galactosylgloboside, globoside, H type 1, H type 2 blood group structures or fucosyl-gangliotetraosyl ceramide, but did react weakly with globo A ceramide. Not only did mAb VK-9 react with carbohydrate-protein conjugates but it could also recognize globo H-ceramide and human tumor cells expressing globo H. These results suggest that globo H-KLH could be explored as a vaccine in the treatment of carcinoma patients.

Animals↗
PubMed1984

Treatment of bulimia with brief psychoeducational group therapy.

Two groups of 10 normal-weight bulimic women received short-term, structured group treatment beginning 3 weeks apart in a multiple baseline design. The multifaceted treatment approach incorporated education, self-monitoring, goal setting, assertion training, relaxation, and cognitive restructuring. Results showed an overall reduction of 70% in binge/purge episodes. There were significant improvements in psychological functioning, including self-esteem, depression, assertiveness, and pathological attitudes about eating.

Adult↗
PubMedDate not supplied

Promoting wellness in HIV-support groups.

This investigation explored the views, meanings, and perspectives of male homosexuals who sought help from each other in community support groups. They sought support to face the sometimes overwhelming reality of living with the life-threatening effects of HIV infection. The research design was qualitative, using a naturalistic approach to generate an understanding of group support for male homosexuals with HIV infection. Data were analyzed inductively, using the constant comparative method. Four major categories of data identified were: intimacy, group process, group structure, and meaning. The author gives recommendations for conducting HIV-support groups.

Adult↗
PubMed1987

Plasticity in the organization of adult cerebral cortical maps: a computer simulation based on neuronal group selection.

Recent experimental evidence from the somatosensory, auditory, and visual systems documents the existence of functional plasticity in topographic map organization in adult animals. This evidence suggests that an ongoing competitive organizing process controls the locations of map borders and the receptive field properties of neurons. A computer model based on the process of neuronal group selection has been constructed that accounts for reported results on map plasticity in somatosensory cortex. The simulations construct a network of locally connected excitatory and inhibitory cells that receives topographic projections from 2 receptor sheets corresponding to the glabrous and dorsal surfaces of the hand (a typical simulation involves approximately 1500 cells, 70,000 intrinsic and 100,000 extrinsic connections). Both intrinsic and extrinsic connections undergo activity-dependent modifications according to a synaptic rule based on heterosynaptic interactions. Repeated stimulation of the receptor sheet resulted in the formation of neuronal groups-local sets of strongly interconnected neurons in the network. Cells in most groups were found to have similar receptive fields: they were exclusively glabrous or dorsal despite equal numbers of anatomical connections from both surfaces. The sharpness of map borders was due to the sharpness of the underlying group structure; shifts in the locations of these borders resulted from competition between groups. Following perturbations of the input, the network underwent changes similar to those observed experimentally in monkey somatosensory cortex. Repeated local tapping on the receptor sheet resulted in a large increase in the magnification factor of the stimulated region. Transection of the connections from a glabrous region resulted in the organization of a new representation of corresponding dorsal region. The detailed simulations provide several insights into the mechanisms of such changes, as well as a series of predictions about cortical behavior for further experimental test.

Brain Mapping↗
PubMed1995

Is water structure around hydrophobic groups clathrate-like?

The term "clathrate structure" is quantified for solvation of nonpolar groups by enumerating hydrogen-bonded ring sizes both in the solvation shell and through the shell-bulk interface and comparing it to a bulk control using the ST4 water model. For clathrate-like structure to be evident, the distributions along the hydrophobic surface are expected to be dominated by pentagons, with significant depletion of hexagons and larger polygons. While the distribution in this region is indeed distinguished by a large number of pentagons, there are significant contributions from hexagons and larger rings as well. Calculated polygon distributions through the shell-bulk interface indicate that when water structure is highly cooperative along the hydrophobic surface, hydrogen-bonded pathways leading back into bulk are then reduced. These results are qualitatively consistent with the observation that hydrophobicity is proportional to the nonpolar solute surface area.

Journal Article↗
PubMed2003

Group II introns: structure and catalytic versatility of large natural ribozymes.

Group II introns are large, natural catalytic RNAs or ribozymes that were discovered in organelles of certain protists, fungi, algae, and plants and more recently also in prokaryotic organisms. In vitro, some members were found to self-splice from their pre-RNAs by two consecutive transesterification reactions joining the flanking exons and releasing the intron in a typical lariat form. Apart from self-splicing, a variety of other in vitro activities have been detected for group II introns demonstrating their amazing catalytic versatility. Group II introns fold into a conserved secondary structure consisting of six domains radiating from a central wheel that brings the 5' and 3' splice junction into close proximity. Domain 1 is the largest domain that is assumed to deliver the molecular scaffold assembling the intron in its active structure, while domain 5 is the phylogenetically most conserved part that represents the active site of the ribozyme. In vivo, the splicing reaction of many, if not all group II introns is assisted by proteins either encoded by the introns themselves (maturases), or encoded by other genes of the host organisms. The host proteins known to date have additional cellular functions and seem to have been adapted for splicing during evolution. Some of the protein-encoding group II introns were also shown to act as mobile genetic elements. They can integrate efficiently into intronless alleles of the same gene (homing) and at much lower frequencies into ectopic sites (transposition). The mobility process depends on intron encoded protein functions (endonuclease and reverse transcriptase) and on the intron RNA. This review provides a comprehensive survey of the structure/function relationships and the reaction potential of group II introns, the structurally most complicated, but also most fascinating ribozymes when looking at their catalytic repertoire in vitro and in vivo.

Base Sequence↗
PubMed1995

Protein structure refinement based on paramagnetic NMR shifts: applications to wild-type and mutant forms of cytochrome c.

A new approach to NMR solution structure refinement is introduced that uses paramagnetic effects on nuclear chemical shifts as constraints in energy minimization or molecular dynamics calculations. Chemical shift differences between oxidized and reduced forms of horse cytochrome c for more than 300 protons were used as constraints to refine the structure of the wild-type protein in solution and to define the structural changes induced by a Leu 94 to Val mutation. A single round of constrained minimization, using the crystal structure as the starting point, converged to a low-energy structure with an RMS deviation between calculated and observed pseudo-contact shifts of 0.045 ppm, 7.5-fold lower than the starting structure. At the same time, the procedure provided stereospecific assignments for more than 45 pairs of methylene protons and methyl groups. Structural changes caused by the mutation were determined to a precision of better than 0.3 A. Structure determination based on dipolar paramagnetic (pseudocontact) shifts is applicable to molecules containing anisotropic paramagnetic centers with short electronic relaxation times, including numerous naturally occurring metalloproteins, as well as proteins or nucleic acids to which a paramagnetic metal ion or ligand may be attached. The long range of paramagnetic shift effects (up to 20 A from the iron in the case of cytochrome c) provides global structural constraints, which, in conjunction with conventional NMR distance and dihedral angle constraints, will enhance the precision of NMR solution structure determination.

Cytochrome c Group↗
PubMed2007

[Frankfurt group social communication and interaction skills training for children and adolescents with autism spectrum disorders].

OBJECTIVE: Despite the recognition of the need for group-based training programmes for children and adolescents with autistic disorders, there are only very few specific German-speaking training programmes available. Since 2003, a structured group training programme on social skills for children and adolescents with high-functioning autism or Asperger syndrome has been developed and conducted at our department. The training programme focuses on the main deficits of those disorders. Thus, the primary goal is to improve communication and interaction skills. METHOD: Participants are children and adolescents without significant cognitive and language delays. Principles of intervention include structured formats, combination of theoretical and practical elements, predictable rules, consideration of individual difficulties, and sequential and progressive learning. Techniques range from structured games, the training of affect recognition, group activities, role play, team discussions, and feedback to homework using a newly designed manual on our group-based social skill training programme and curriculum. Generally, three groups of 5-7 participants each and of different age range (children, adolescents) meet weekly/biweekly for 1-1.5 hours (excluding the holidays). Two trainers--who change during the programme--carry out each of the sessions. Trainers meet regularly with the parents to discuss experiences and to provide details of the programme. RESULTS: Acceptance by and satisfaction with the programme are high among participants, as is the mutual recognition of and tolerance of their respective problems. Both feedback from parents and trainers' clinical impressions indicate distinct improvement of verbalization and contact abilities. Participants seem to benefit particularly from role play. CONCLUSIONS: Qualtitative measures (impressions of the participants, their parents and their trainers with regard to change in behaviour skills) suggest mounting interaction, communication, and problem-solving skills during the group treatment. An ongoing pilot evaluation also includes measurements of effects in everyday settings. Depending on the results, the training subsequently could be conducted and evaluated in groups with both pervasive developmental, as well as other psychiatric disorders.

Adolescent↗
PubMed1983

A small group strategy for improving compliance behavior and blood pressure control.

A brief small group structured approach to improving compliance behavior and blood pressure control is described. The group intervention is based on the results of a diagnostic baseline survey of ambulatory hypertensive patients receiving care in an inner-city hospital. It was tailored to meet the expressed needs of that population group. Three main steps characterize the intervention: examining health behaviors and compliance issues with the patients using rehearsal of specific coping skills in problem solving activity; using Locus of Control concepts to facilitate process; and encouraging the patient to practice and apply the coping skills in stressful situations. Major themes within the group sessions and general outcomes are examined.

Blood Pressure↗
PubMedDate not supplied

Effect of root death and decay on dissipation of polycyclic aromatic hydrocarbons in the rhizosphere of yellow sweet clover and tall fescue.

A 12-mo greenhouse study was conducted to evaluate the contribution of root death and decay on the dissipation of polycyclic aromatic hydrocarbons (PAHs) in rhizosphere soil. The contaminated soil was previously treated by land-farming, but residual PAHs remained after treatment. Tall fescue (Festuca arundinacea Schreb.) and yellow sweet clover (Melilotus officinalis Lam.) were the target plants. To specifically evaluate the effect of root decay on contaminant dissipation, plants were treated with glyphosate, a broad spectrum herbicide, to induce root decay. Although tall fescue treatments had the highest root and shoot biomass and root surface area, this plant did not result in the highest contaminant degradation rates. Significant differences were noted between treatments for seven PAHs, with the active yellow sweet clover resulting in 60 to 75% degradation of these compounds. Induced root death and decay did not produce a significant enhancement of PAH degradation. The PAH microbial degrader populations in the vegetated treatments were more than 100 times greater than those in the unvegetated control. The phospholipid fatty acid (PLFA) structural group profile shifted over the growing period, indicating a change in the community structure. In conclusion, phytoremediation was shown to be an effective polishing tool for PAH-affected soil previously subjected to biological treatment.

Biodegradation, Environmental↗
PubMed2006

Running a group.

Self-help groups, e.g. for breast-feeding support or postnatal depression, can be an effective resource for clients. They can also be an effective use of professionals'time in primary care. A health visitor offers practical suggestions for starting and guiding a new group, including the need for professionals to think creatively and flexibly about group structures. The advice is to keep these simple, audit regularly and allow the groups to evolve.

Community Health Nursing↗
PubMed2001

Microsatellite analysis of genetic variation among and within Alpine marmot populations in the French Alps.

The genetic structure of the Alpine marmot, Marmota marmota, was studied by an analysis of five polymorphic microsatellite loci. Eight locations were sampled in the French Alps, one from Les Ecrins valley (n = 160), another from La Sassière valley (n = 289) and the six others from the Maurienne valley (n = 139). Information on social group structure was available for both Les Ecrins and La Sassière but not for the other samples. The high levels of genetic diversity observed are at odds with the results obtained using microsatellites, minisatellites and allozymes on Alpine marmots from Germany, Austria and Switzerland. Strong deficits in heterozygotes were found in Les Ecrins and La Sassière. They are caused by a Wahlund effect due to the family structure (i.e. differentiation between the family groups). The family groups exhibit excess of heterozygotes rather than deficits. This may be caused by outbreeding and this is compatible with recent results from the genetics of related social species when information on the social structure is taken into account. The observed outbreeding could be the result of females mating with transient males or males coming from neighbouring colonies. Both indicate that the species may not be as monogamous as is usually believed. The results are also compatible with a male-biased dispersal but do not allow us to exclude some female migration. We also found a significant correlation between geographical and genetic distance indicating that isolation by distance could be an issue in marmots. This study is the first that analysed populations of marmots taking into account the social structure within populations and assessing inbreeding at different levels (region, valley, population, and family groups). Our study clearly demonstrated that the sampling strategy and behavioural information can have dramatic effects on both the results and interpretation of the genetic data.

Animals↗
PubMedDate not supplied

A brief group treatment for the modification of denial in child sexual abusers: outcome and follow-up.

We investigated whether brief structured group treatment could produce a reduction of denial of sexual offenses in males convicted of sexually offending against children. Such denial can additionally harm victims and often precludes admission into sex offender treatment programs, thus ruling out an opportunity to decrease the potential of reoffending. The group treatment contained elements of victim empathy, cognitive restructuring, sex education, assertiveness and social skills, education about sex offender therapy, and a discussion of the possible consequences of continued denial. Seventeen child sexual offenders in denial were run in two groups. Despite an average length of denial of nearly two years, by post-treatment the majority of offenders had come out of denial. Moreover, follow-up denial data indicated continued admission, and above-average compliance with subsequent sex offender therapy. Although the lack of an experimental design precludes causal inference, these results are suggestive of an effective method for modifying denial in sex offenders against children.

Adolescent↗
PubMed1990

Analysis of the fine specificities of 11 mouse monoclonal antibodies reactive with type 2 blood group determinants.

The specificity of 11 mouse monoclonal antibodies reacting selectively with type 2 blood group structures was analyzed in detail by studying their reactivities with a panel of standard glycolipids, glycolipids from erythrocytes and blood group glycoproteins. The antibodies reacted with monofucosyl type 2 H, difucosyl type 2 structures (Le gamma) or both; none of the antibodies reacted with type 1 (H, Lea, or Leb) structures. Only a small proportion of the antibodies were completely specific for either type 2H or Le gamma structures. None of the antibodies had identical patterns of reactivity and their specificities were individually distinct. Seven antibodies preferentially agglutinated O and A2 erythrocytes. Anti-Le gamma-specific antibodies, except mAb101, did not agglutinate erythrocytes or react with glycolipids from erythrocytes, indicating the absence of Le gamma structures in erythrocyte glycolipids. The ability of some antibodies to react with A erythrocytes was shown to be due to cross-reactivity of the antibodies with type 3 (repetitive) A structures. The study demonstrates that monoclonal anti-carbohydrate antibodies tend to react with a range of related, and even distantly related, structure in a pattern characteristic of each antibody and that very few antibodies have extremely restricted specificities.

ABO Blood-Group System↗
PubMed1978

Horizontal cells of the carp retina: Golgi impregnation and Procion-Yellow injection.

Application of two methods for the selective staining of neurons, Golgi impregnation and intracellular marking with Procion Yellow, has revealed the anatomical arrangements of the horizontal cells in the carp retina. There are two basic horizontal-cell types, those with axons and these without. The former can be subdivided into three groups on the basis of the pattern of branching of the dendrites. These three structural groups are also functionally distinct, as shown by the electrical recordings made during Procion-Yellow injection. The axons of these three types of cell project into the proximal part of the inner nuclear layer, where they expand to form morphologically indistinguishable terminals. Fine horizontal processes leave the surfaces of these axon terminals. The functional behavior of a terminal resembles that of the associated soma. The horizontal cells lacking axons vary in morphological appearance, but they are similar functionally.

Animals↗
PubMed1989

Three-dimensional model of the insect-directed scorpion toxin from Androctonus australis Hector and its implication for the evolution of scorpion toxins in general.

The three-dimensional structure of the insect-directed toxin from the scorpion Androctonus australis Hector has been modelled using computer graphics and energy-minimization techniques. The model-building procedure was based on the known high resolution structures of two scorpion toxins of different types: toxin II from A. australis Hector, an alpha-toxin, and variant 3 from Centruroides sculpturatus Ewing that belongs to the beta-toxin structural group. Although the insect-directed toxin has one atypical disulfide bridge, the general structural features of the scorpion toxin family, including the presence of a "conserved-hydrophobic" surface, seem to be well-conserved. However, the orientation and length of some loops and regions thought to be important for toxicity are different for alpha-toxins, beta-toxins, and the insect-directed toxin. Thus, the binding of a scorpion toxin to its site on the Na+ channel seems to be based on (1) the presence of a surface containing a series of conserved and/or hydrophobic residues, more or less common to all these molecules, and (2) an adjacent area that modulates the specificity of the interaction.

Amino Acid Sequence↗