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PubMed1996

Positive-negative evaluation (PNE) scale: a new dimension of the subjective domains of quality of life measure.

A new subjective measure of Quality of Life (QOL), the Subjective Domains of Quality of Life Measure (SDQLM), developed by Bar-On and Amir, is a qualitative and quantitative self-structured method shown to have internal reliability and construct validity compared with quantitative pre-structured measures and evaluations by spouses and physicians. To earlier analyses on a sample of male hypertensives and normotensives, we added a content analysis which is reported here, in which the elicited QOL domains were assessed according to whether the respondent evaluated his QOL domains as positive, negative or neutral/mixed. The content analysis showed that respondents may be classified on a continuous scale from stable positive to stable negative evaluations of their QOL domains (before-after measurement). The scale was assembled by ordinal ranging of the answers at two points in time (one year apart). A respondent who evaluated his domain as positive at both such points was ranked highest on the scale, negative at both points the lowest and the two remaining possibilities constituted the middle range. Analysis of the data showed that the SDQLM with this additional content analysis correlated significantly with depression scale scores, sexual functioning, physical fitness, work satisfaction, quality of sleep, hardiness, education and age, as well as individual self-rating of QOL. The subjective measure based on self-elicited domains with PNE was shown to be an important construct compared with pre-structured measures of QOL.

Adult↗
PubMed2000

Stereolithographic biomodeling to create tangible hard copies of cardiac structures from echocardiographic data: in vitro and in vivo validation.

OBJECTIVES: This study investigated the feasibility, accuracy and clinical potential of creating polymer hard copies of echocardiographic data using stereolithography. BACKGROUND: Three-dimensional (3D) echocardiography has so far been limited by the need to display reconstructed 3D objects on a two-dimensional screen. Thus, tangible stereolithographic polymer models created from echocardiographic data could enhance our spatial perception of cardiac anatomy and pathology. METHODS: Hard-copy replicas of water-filled latex balloon phantoms (n = 7) and porcine liver specimens (n = 12) were generated from echocardiographic images using stereolithography (computerized laser polymerization). In addition, we created 24 models of the mitral valve from 12 transesophageal studies (normal = 6, mitral stenosis n = 4, prolapse/flail leaflet n = 8, annular dilation n = 2, leaflet restriction n = 2 and following mitral valve repair n = 2). RESULTS: Excellent agreement was found for comparison of volumes (r = 0.98, SEE = 3.46 mm3, mean difference = 0.25 +/- 3.33 mm3) and maximal dimensions (r = 0.99, SEE = 0.16 cm, mean difference = 0.03 +/- 0.16 cm) between phantoms and their corresponding replicas. Visual and tactile examination of mitral valve models by two blinded observers allowed correct depiction of mitral valve anatomy and pathology in all cases. CONCLUSIONS: Stereolithographic modeling of echocardiographic images is feasible and provides tangible polyacrylic models that are true to scale, shape and volume. Such models offer accurate depiction of mitral valve anatomy and pathology in patients studied with transesophageal echocardiography. This technique could have substantial impact on diagnosis, management and preoperative planning in complex cardiovascular disorders.

Computer Systems↗
PubMed2005

Spectroscopic and computational studies of Ni superoxide dismutase: electronic structure contributions to enzymatic function.

Ni-containing superoxide dismutase (NiSOD) is the most recently discovered member of the class of metalloenzymes that detoxify the superoxide radical in aerobic organisms. In this study, we have employed a variety of spectroscopic and computational methods to probe the electronic structure of the NiSOD active site in both its oxidized (NiSOD(ox), possessing a low-spin (S = (1)/(2)) Ni(3+) center) and reduced (NiSOD(red), containing a diamagnetic Ni(2+) center) states. Our experimentally validated computed electronic-structure description for NiSOD(ox) reveals strong sigma-bonding interactions between Ni and the equatorial S/N ligands, which give rise to intense charge-transfer transitions in the near-UV region of the absorption spectrum. Resonance Raman (rR) spectra obtained with laser excitation in this region exhibit two features at 349 and 365 cm(-)(1) that are assigned to Ni-S(Cys) stretching modes. The NiSOD(red) active site also exhibits a high degree of metal-ligand bond covalency as well as filled/filled pi-interactions between Ni and S/N orbitals, which serve to adjust the redox potential of the Ni(2+) center. Comparison of our computational results for NiSOD(red) with those obtained in parallel studies of synthetic [NiS(2)N(2)] complexes reveals that the presence of an anionic N-donor ligand is crucial for promoting metal-based (versus S-based) oxidation of the active site. The implications of our electronic-structure descriptions with respect to the function of NiSOD are discussed, and a comparison of M-S(Cys) bonding in NiSOD and other metalloenzymes with sulfur ligation is provided.

Binding Sites↗
PubMed2002

Development and validation of opioid ligand-receptor interaction models: the structural basis of mu vs delta selectivity.

Opioid receptor binding conformations for two structurally related, conformationally constrained tetrapeptides, JOM-6 ( micro receptor selective) and JOM-13 (delta receptor selective), were deduced using conformational analysis of these ligands and analogs with additional conformational restrictions. Docking of these ligands in their binding conformations to opioid receptor structural models, based upon the published rhodopsin X-ray structure, implicates specific structural features of the micro and delta receptor ligand binding sites as forming the basis for the micro selectivity of JOM-6 and the delta selectivity of JOM-13. In particular, the presence of E229 in the micro receptor (in place of the corresponding D210 of the delta receptor) causes an adverse electrostatic interaction with C-terminal carboxylate-containing ligands, resulting in the observed preference of ligands with an uncharged C-terminus for the micro receptor. In addition, the requirement that the Phe3 side chain of JOM-13 assume a gauche orientation for optimal delta binding, whereas the Phe3 side chain of JOM-6 must be in a trans orientation for high-affinity micro binding can be largely attributed to the steric effect of replacement of L300 of the delta receptor by W318 of the micro receptor. Testing this hypothesis by examining the binding of JOM-6 and several of its key analogs with specific micro receptor mutants is described. Our initial results are consistent with the proposed ligand-receptor interaction models.

Binding Sites↗
PubMed2001

Development and validation of the Glasgow Epilepsy Outcome Scale (GEOS): a new instrument for measuring concerns about epilepsy in people with mental retardation.

PURPOSE: To develop a measure for use with adults with epilepsy and mental retardation, capable of assessing both clinical and care concerns and of quantifying treatment outcomes. METHODS: Extensive validational and other psychometric evaluation was undertaken, comprising initial scale development work with 48 carers and 46 health practitioners, followed by formal field testing on a sample of 186 patients, using 384 respondents (160 clinicians, 141 staff, 83 family). Recognised qualitative methods were applied to identify central themes, and psychometric procedures generated data on validity, reliability, and component structure. RESULTS: A total of 1,007 items of concern was generated, which was reduced systematically to a representative set of 90 items. The GEOS-90 comprises four subscales: concerns about "seizures," "treatment," "caring," and "social impact," each explaining approximately 70% of variance. Subscales and factor scales had strong internal consistency (alpha > or = 0.82). Stepwise linear regression was applied to derive a short-form version with similar structure. Thirty-five items were retained (GEOS-35; alpha > or = 0.89). Both scales discriminated moderately on clinical variables (number of seizure types, mono- vs. polytherapy, seizure frequency; all values of p < 0.05) and demonstrated concurrent validity with interview ratings from the ELDQOL (p < 0.05). CONCLUSIONS: The GEOS scales appear valid and reliable for use with clinical populations of people with mental retardation.

Adolescent↗
PubMed2002

The assessment of grief among Hong Kong Chinese: a preliminary report.

This is a preliminary report of a study that examined the clinical usefulness of the Chinese Grief Reaction Assessment Form (GRAF). The validity, reliability, and factor structure of the form were also explored. We administered the GRAF to 180 bereaved individuals during intake interview for bereavement counseling. The GRAF has obtained good internal Cronbach's alpha reliability of .89 and showed its validity in being able to discriminate between the grief reactions of bereaved individuals experiencing anticipated and unanticipated death in the predicted direction. Bereaved women had stronger grief reaction than men. The item "I do not want to abandon him/her" obtained the highest mean ranked scores among both bereaved men and bereaved women. Our findings support the use of the GRAF as a clinical tool to assess psychological symptoms associated with bereavement among Hong Kong Chinese, which also holds promise for research and program evaluation.

China↗
PubMed1998

Structure of type III antifreeze protein at 277 K.

Fish antifreeze proteins (AFP's) depress the freezing point of blood and other body fluids below that of the surrounding seawater by binding to and inhibiting the growth of seed ice crystals. The high-resolution crystal structure of type III AFP, determined at room temperature, reveals a remarkably flat surface containing most of the ice-binding residues [Jia et al. (1996). Nature (London), 384, 285-288]. Since AFP's function at temperatures close to 273 K, it is important to know whether the structure determined at room temperature undergoes any change at much lower temperature. Therefore, type III AFP has been crystallized at 277 K and its structure determined. Although crystallization conditions at 277 K were similar to those at approximately 295 K, crystal growth took much longer at the lower temperature. Crystals grown at the two temperatures were isomorphous. Initial crystals appeared within 40-50 d and grew to their final size in about 8-12 months, instead of a couple of days at approximately 295 K. The type III antifreeze protein structure from crystals grown at 277 K was essentially the same as that determined at approximately 295 K, with the exception of some minor changes in side-chain conformation. The result is an indication that temperature has a minimal effect on the structure of type III AFP, thus lending increased physiological validity to the room-temperature structure which was used for the initial ice-binding modelling.

Animals↗
PubMed2004

Validation of helical tilt angles in the solution NMR structure of the Z domain of Staphylococcal protein A by combined analysis of residual dipolar coupling and NOE data.

Staphylococcal protein A (SpA) is a virulence factor from Staphylococcus aureus that is able to bind to immunoglobulins. The 3D structures of its immunoglobulin (Ig) binding domains have been extensively studied by NMR and X-ray crystallography, and are often used as model structures in developing de novo or ab initio strategies for predicting protein structure. These small three-helix-bundle structures, reported in free proteins or Ig-bound complexes, have been determined previously using medium- to high-resolution data. Although the location and relative orientation of the three helices in most of these published 3D domain structures are consistent, there are significant differences among the reported structures regarding the tilt angle of the first helix (helix 1). We have applied residual dipolar coupling data, together with nuclear Overhauser enhancement and scalar coupling data, in refining the NMR solution structure of an engineered IgG-binding domain (Z domain) of SpA. Our results demonstrate that the three helices are almost perfectly antiparallel in orientation, with the first helix tilting slightly away from the other two helices. We propose that this high-accuracy structure of the Z domain of SpA is a more suitable target for theoretical predictions of the free domain structure than previously published lower-accuracy structures of protein A domains.

Binding Sites↗
PubMed2006

Computational models of structure-function relationships in the pulmonary circulation and their validation.

The pulmonary airway, arterial, venous and capillary networks are vast complex branching and converging systems that are mechanically coupled to the surrounding lung tissue. Early studies that examined vascular or airway geometry relied on measurements from casts, but medical imaging now enables measurement of the lung in vivo, at controlled lung volumes. The high-quality data that imaging provides have prompted development of increasingly sophisticated models of the geometry of the airway and pulmonary vascular trees. The accurate spatial relationships between airway, vessel and tissue in these imaging-derived models are necessary for computational analysis that aims to elucidate regional airway-vessel-tissue interactions. Predictions of blood flow through multiscale imaging-derived models of the pulmonary arteries and capillary bed reveal geometry-dependent patterns of perfusion in response to gravity and lung orientation that cannot be predicted with simplified, summary representations of the pulmonary transport trees. Validation of such predictions against measures from functional imaging holds significant potential for explaining and differentiating normal and disease-related heterogeneity in regional blood flow calculated using perfusion imaging.

Computer Simulation↗
PubMed1999

Single-crystal-like diffraction data from polycrystalline materials

A method for solving structures from powder diffraction data was developed, and its validity was demonstrated on three complex structures. The method uses a textured sample and exploits the high intensity and parallel nature of synchrotron radiation. In principle, crystal structures as complex as those routinely solved by single-crystal methods can be determined with this approach. For example, the as-synthesized form of the zeolite UTD-1, with 69 nonhydrogen atoms in the asymmetric unit, could be solved directly. With this method, a larger range of structural complexity becomes accessible to scientists interested in the structures of polycrystalline materials that cannot be grown as single crystals.

Journal Article↗
PubMed1999

Recall and validation of phobia origins as a function of a structured interview versus the Phobia Origins Questionnaire.

Memory for fear onset events was examined in 43 dog-fearful and 48 blood/injection-fearful participants. Half of each fear type was administered the Phobia Origins Questionnaire (POQ), and half the Phobia Origins Structured Interview (POSI). Written accounts of recalled onset experiences were sent to participants' parents for verification. More participants assessed by the POQ reported a phobia onset event (93%) than did those assessed by the POSI (54%). A majority in both methods recalled conditioning-like experiences. The POQ resulted in more reports of vicarious and informational onset reports than did the POSI. Parents confirmed more onset event reports obtained by the POSI (81%) than those obtained by the POQ, (50%). In addition, in 21% of cases where a child recalled an event, a parent reported an onset event that predated the one provided by the child. Results are discussed in terms of memory mechanisms operative in autobiographical memories.

Adolescent↗
PubMed1989

[Validation of the concept of morphofunctional unity of the structural components of the human mandible].

Interconnections of the mandibular macro- and microsigns have been studied in 98 corpses of men. By means of the multidimensional analysis discreteness and autonomy of the mandibular structural components are revealed; this demonstrates that there is a possibility of an active arrangement of parts and structural components of the mandible depending on the external environmental conditions in order to reach optimal terminal functional effect--chewing. The most discriminative signs of contrasting variants in the structure of the mandible are revealed.

Adaptation, Physiological↗
PubMed2003

Relaxation-based structure refinement and backbone molecular dynamics of the dynein motor domain-associated light chain.

The light chain 1 (LC1) polypeptide is a member of the leucine-rich repeat protein family and binds at or near the ATP hydrolytic site within the motor domain of the gamma heavy chain from Chlamydomonas outer arm dynein. It consists of an N-terminal helix, a central barrel formed from six leucine-rich repeats that fold as beta beta alpha units, and a C-terminal helical domain that protrudes from the main axis defined by the leucine-rich repeats. Interaction with the gamma heavy chain is likely mediated through a hydrophobic patch on the larger beta sheet face, and the C-terminal region is predicted to insert into the dynein ATP hydrolytic site. Here we have used 1H-15N heteronuclear relaxation measurements obtained at 500 and 600 MHz to refine and validate the LC1 solution structure. In this refined structure, the C-terminal helix is significantly reoriented by more than 20 degrees as compared to the control and provides a more precise understanding of the potential regulatory role of this domain. We also employed the refined structure to perform a dynamic analysis of LC1 using the 600 MHz data set. These results, which were cross validated using the 500 MHz data set, strongly support identification of the predicted LC1 binding surfaces and provide additional insight into the interaction mechanisms of leucine-rich repeat proteins.

Animals↗
PubMed2006

Establishment of mass spectrometric fingerprints of novel synthetic cholesteryl neoglycolipids: the presence of a unique C-glycoside species during electrospray ionization and during collision-induced dissociation tandem mass spectrometry.

In this study we evaluated the fragmentation pattern of 16 novel amphiphilic neoglycolipid cholesteryl derivatives that can be efficiently used to increase cationic liposomal stability and to enhance gene transfer ability. These neoglycolipids bear different sugar moieties, such as D-glucosamine, N-acetyl-D-glucosamine, N-trideuterioacetyl-D-glucosamine, N-acetyllactosamine, L-fucose, N-allyloxycarbonyl-D-glucosamine, and some of their per-O-acetylated derivatives. Regardless of the structure of the tested neoglycolipid, QqToF-MS analysis using electrospray ionization (ESI) source showed abundant protonated [M+H]+ species. We also identified by both QqToF-MS and low-energy collision tandem mass spectrometry (CID-MS/MS) of the [M+H]+ ion, the presence of specific common fingerprint fragment ions: [Cholestene]+, sugar [oxonium]+, [(Sugar-spacer-OH)+H]+, [oxonium-H2O]+, and [(Cholesterol-spacer-OH)+H]+. In addition, we observed a unique ion that could not be rationally explained by the expected fragmentation of these amphiphilic molecules. The structure of this ion was tentatively proposed with that of a C-glycoside species formed by a chemical reaction between the sugar portion and the cholesterol. MS/MS analysis of this unique [C-glycoside]+ confirmed the validity of the proposed structure of this ion. The presence of an amino group at position C-2 and free hydroxyl groups of the sugar motif is crucial for the formation of a "reactive" sugar oxonium ion that can form the [C-glycoside]+ species. In summary, we precisely established the fragmentation patterns of the tested series of neoglycolipid cholesteryl derivatives and authenticated their structure as well; moreover, we speculated on the formation of a C-glycoside with the ESI source under atmospheric pressure and in the collision cell during MS/MS analysis.

Carbohydrate Sequence↗
PubMed2005

Typification of cider brandy on the basis of cider used in its manufacture.

A study of typification of cider brandies on the basis of the origin of the raw material used in their manufacture was conducted using chemometric techniques (principal component analysis, linear discriminant analysis, and Bayesian analysis) together with their composition in volatile compounds, as analyzed by gas chromatography with flame ionization to detect the major volatiles and by mass spectrometric to detect the minor ones. Significant principal components computed by a double cross-validation procedure allowed the structure of the database to be visualized as a function of the raw material, that is, cider made from fresh apple juice versus cider made from apple juice concentrate. Feasible and robust discriminant rules were computed and validated by a cross-validation procedure that allowed the authors to classify fresh and concentrate cider brandies, obtaining classification hits of >92%. The most discriminating variables for typifying cider brandies according to their raw material were 1-butanol and ethyl hexanoate.

Alcoholic Beverages↗