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Results for “New approach methodologies”

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PubMed1998

A modified functional global test to measure protein C, protein S activities and the activated protein C-resistance phenotype.

Identifying a defect affecting the protein C/protein S (PC/PS) anticoagulant system, using a single global test, has recently become possible thanks to a new methodological approach based on the activation of endogenous plasma PC by Protac, derived from Agkistrodon Contortix snake venom (ACV). The introduction of a commercial test (ProC Global), ACV-based, provides a useful tool for the screening of thrombotic patients since the most frequent causes of inherited thrombophilia are found in the PC/PS system. The test provides information only on the global activity of the anticoagulant pathway but not on PC and PS activity or on the factor V related conditions (e.g., FV Leiden). The present study shows that by carrying out the test alternating the presence of PC-, PS-, or FV-deficient plasma and using appropriate amounts of ACV, it is possible to increase the specificity of the test to correctly evaluate respectively the PC or PS activities or the activated protein C resistance condition (APC-R). These simple modifications applied to the original commercial test allow to detect exactly, using a single, basic methodology, the principal defects affecting the PC/PS anticoagulant pathway. Furthermore, carrying out the tests on an automated coagulometer, in combination or not with the classic ProC Global assay, it is possible to use a unique reagent profile to simultaneously investigate in the same or different samples, the PC, PS, and APC-R defect.

Activated Protein C Resistance↗

PubMed2001

Understanding the dynamics of illness and help-seeking: event-structure analysis and a Cambodian-American narrative of "spirit invasion".

Event structure analysis (ESA) and its computer analog, ETHNO, represent a class of relatively new methodological approaches that make it possible to capture the complexity of help-seeking interactions. Using narrative data from a study of Cambodian-American help-seeking interactions within a circumscribed illness episode, this paper demonstrates the feasibility of using ESA/ETHNO to illuminate how event sequence, operant illness beliefs, structural conditions, and human agency interpenetrate and shape the occurrence and timing of pivotal actions and the denouement of a help-seeking episode.

Anthropology, Cultural↗

PubMed2000

Methodological and clinical implications of the relocation of the minimal luminal diameter after intracoronary radiation therapy. Dose Finding Study Group.

OBJECTIVES: The aims of the study were to determine the incidence of relocation of the minimal luminal diameter (MLD) after beta-radiation therapy following balloon angioplasty (BA) and to describe a new methodological approach to define the effect of brachytherapy on treated coronary stenoses. BACKGROUND: Luminal diameter of coronary lesions may increase over time following angioplasty and irradiation. As a result, the MLD at follow-up may be relocated from its location preintervention, which may induce misleading results when a restricted definition of the target segment by quantitative coronary angiography (QCA) is performed. METHODS: Patients treated with BA followed by intracoronary brachytherapy according to the Dose-Finding Study constituted the study population. A historical cohort of patients treated with BA was used as control group. To be included in the analysis, an accurate angiographic documentation of all instrumentations during the procedure was mandatory. In the irradiated patients, four regions were defined by QCA: vessel segment (VS), target segment (TS), injured segment (INS), and irradiated segment (IRS). RESULTS: Sixty-five patients from the Dose-Finding Study and 179 control patients were included. At follow-up, MLD was relocated more often in the radiation group (78.5% vs. 26.3%; p < 0.0001). The rate of >50% diameter stenosis differed among the four predefined regions: 3.1% in the TS; 7.7% in the INS; 9.2% in the IRS and 13.8% in the VS. CONCLUSIONS: Relocation of the MLD is commonly demonstrated after BA and brachytherapy, and it should be taken into account during the analysis of the results of radiation clinical trials.

Angioplasty, Balloon↗

PubMed2001

N- and R-cadherins expression in the rat sciatic nerve demonstrated by postembedding immunogold method on semi-thin sections.

The calcium-dependent adhesion molecules N- and R-cadherins take part in the morphogenesis of the nervous system. The data about their localization in the peripheral nerves postnatum are limited and somewhat controversial. In the present study, a new methodological approach to the immunohistochemical cadherin detection has been applied. The sciatic nerves of 10-day-old rats were immunotested on semi-thin Epon sections by anti-N- and R-cadherins polyclonal antibody and visualized by IgG conjugated to colloidal gold and silver amplification. In the myelinated nerve fibers, an immuno-like activity was associated with the axoplasm and axolemma, the surface of the myelinating Schwann cells and their extracellular matrix. The units of nonmyelinated fibres and their associated glial cells were also intensely immunostained. The myelin sheaths and the glial cytoplasm were immunonegative. The significance of the localization is discussed in regard to the possible role of N- and R-cadherins in the anatomical and functional compartmentation of peripheral nerves.

Animals↗

PubMed2004

A novel method of oral fluid collection to monitor immunity to common viral infections.

Serological surveys among representative population samples have proved rare given their reliance on invasive sample collection. We therefore completed the first population-based postal survey of immunity in England and Wales using new oral fluid technology. This paper examines the feasibility of this new methodological approach. Nearly 5500 oral fluid samples were collected, with individual demographic and social data via a questionnaire, from persons under 45 years of age recruited through general practices. Instructions were accurately followed with only 1% of samples returned without risk-factor data. The overall response rate was 40%. Response was independently associated with age, sex and location. Response was highest in children aged 5-14 years, adult females and in rural locations. This approach allowed the successful collection of comprehensive individual risk data, but response rates in adults must be improved if oral fluid surveys are to routinely complement serological surveillance.

Adolescent↗

PubMed2003

Liquid chromatography with on-line electrochemical derivatization and fluorescence detection for the determination of phenols.

A new methodological approach for the determination of monosubstituted phenols is described. After liquid chromatographic separation of the analytes, an on-line electrochemical derivatization is carried out and the reaction products are detected fluorometrically. Phenols are oxidized in the electrochemical cell to form fluorescent dimers and higher oligomers, which were identified by on-line electrochemistry/mass spectrometry. Major advantages of the proposed method include enhanced selectivity and sensitivity. Without prior enrichment of the analytes, limits of detection down to 2 x 10(-9) M (20 fmol) may be reached for selected phenols, e.g., for 4-octylphenol, 4-ethylphenol, and 4-(1-indanyl)phenol. Only readily available instrumentation is required for these measurements.

Journal Article↗

PubMed2005

Commentary: siblings in their families.

Three themes in the contributions to the Special Issue are discussed. The first is new evidence for associations between the quality of sibling relationships and children's adjustment problems and positive development, from research which also takes account of parent-child relationships, and genetic associations. The second is the new methodological approaches to studying the complexity of family patterns in which siblings play a central role (for instance with multilevel modelling) and the study of changes over time. The third is the significance of connections with relationships outside the family especially peer relationships and friendships.

Adaptation, Psychological↗

PubMed1996

Accuracy of a commercially available digitizer: a new method for assessment of errors in linearity.

A commercially available digitizer has been tested for accuracy. The various areas of the digitizing tablet show degrees of precision that can differ for the x- and y-coordinates. The tablet has a mean absolute error of 0.016 mm for the x-coordinate and 0.09 mm for the y-coordinate. Error tended to increase toward the sides of the tablet. Partitioning the error into systematic and random components revealed that the x-error is due mainly to errors in linearity of the digitizer. When compared with the error involved in locating cephalometric landmarks, one can conclude that this type of digitizer is suited for orthodontic purposes. This article describes a new methodological approach to locating and measuring errors in linearity.

Analysis of Variance↗

PubMed2000

Determination of the phospholipid precursor of anandamide and other N-acylethanolamine phospholipids before and after sodium azide-induced toxicity in cultured neocortical neurons.

Phospholipase D-mediated hydrolysis of N-acylethanolamine phospholipids (NAPEs) releases anandamide and other N-acylethanolamines, resulting in different actions at cellular targets in the CNS. Recently, we have demonstrated that these N-acyl lipids accumulate in cultured neocortical neurons subjected to sodium azide-induced cell injury. We here extend the information on the NAPE response, reporting on the composition of N-acylspecies of NAPE, employing a new methodological approach of HPLC-coupled electrospray ionization mass spectrometry. Exposure to sodium azide (5 mM) increased the total amount of NAPE threefold over control levels; however, no alteration of the relative composition of NAPE species was detected. The anandamide precursor (20 : 4-NAPE) constituted only 0.1% of all NAPEs detected in the neurons. Total NAPE species in control cells amounted to 956-1,060 pmol/10(7) cells. Moreover, we detected the presence of an unknown NAPE species with molecular weight identical to 20 : 4-NAPE. This may suggest the presence of a putative stereoisomer of the anandamide precursor with at least one trans-configured double bond in the N-arachidonoyl moiety. These results show that with the present method, neuronal NAPE species can be identified and quantified with respect to N-acyl composition, including a trans-isomer of the anandamide precursor. The anandamide precursor is up-regulated to the same extent as other NAPEs upon neuronal injury.

Animals↗

PubMed1999

Protection against ischemia-reperfusion induced oxidative stress by vitamin E treatment.

The rat heart protection offered by vitamin E against oxidative stress after ischaemia-reperfusion was studied by using a new methodological approach. Functional recovery of hearts from ischaemia-reperfusion was correlated with a traditional index of oxidative stress such as lipid peroxidation and with antioxidant capacity and susceptibility to oxidants of the tissue evaluated by enhanced chemiluminescence techniques. Rats were treated with ten daily i.m. injections of 100 mg/kg body weight of vitamin E. The functional recovery during reperfusion (20 min, following 45 min ischaemia) of Langendorff preparations from control (vehicle-injected) and vitamin E treated rats was evaluated in terms of heart rate, left ventricular developed pressure (LVDP), double product (= heart rate. LVDP) and coronary flow recovery. Vitamin E treatment significantly improved functional recovery of heart rate, LVDP, double product and coronary flow. It also increased the level of vitamin E and reduced the levels of both malondialdehyde and hydroperoxides in the heart tissue at the end of the ischaemia-reperfusion protocol. In contrast, it did not affect the antioxidant capacity and the response of heart homogenates to in vitro oxidative stress measured after ischaemia-reperfusion. These results show a protective action of vitamin E treatment against lipid peroxidation and cardiac dysfunction associated with ischaemia-reperfusion. Although the precise mechanism of this protection is not evident, our model in part suggests a role of vitamin E other than as a free radical scavenger.

Animals↗

PubMed2002

Determination of haploid DNA sequences in humans: application to the glucocerebrosidase pseudogene.

Variation analyses in the human genome at the sequence level, especially human genetic population analysis and genetic epidemiology, are hampered by the difficulty to ascertain haplotypes on autosomal regions. We have designed a new methodological approach to obtain autosomal haploid sequences from diploid organisms. First, genotypes are unambiguously determined through long-range PCR and diploid DNA sequencing. Second, cloning the whole PCR-amplified segment and sequencing a single clone for those fragments that presented a heterozygous position discern the allelic phase. The second allele is deduced from the genotype, and the phase reconfirmed by sequencing a second clone. A hundred human chromosomes were analysed for a 5.4 kb encompassing the glucocerebrosidase pseudogene on human chromosome 1. Haplotypes were unambiguously ascertained for all samples. The manner to combine the used techniques makes this approach a novelty. Haploid sequences from diploid organisms are obtained in a less time consuming and more accurate manner than in other used procedures.

Glucosylceramidase↗

PubMed1994

Measuring liability to schizophrenia: progress report 1994: editors' introduction.

The first aim of this issue of the Schizophrenia Bulletin is to provide an up-to-date review of the major domains of research in the experimental psychopathology of schizophrenia, in which important contributions to our understanding of putative pathophysiologic mechanisms have been made. This research has identified several biobehavioral traits as measures of enhanced liability to schizophrenia. Rather than present a substantive review of the research on a particular trait, the authors of several articles focus on a critical appraisal and evaluation of the literature since 1987 in their particular area. The second aim of this issue is to present new methodologic approaches and conceptualizations for incorporating biobehavioral trait data in future psychiatric research designs. Now is the time not only to recognize past contributions but also to recognize that further advances in our understanding of the etiology and pathophysiology of schizophrenia may depend on continued research in experimental psychopathology that culminates in an integration in both methods and research design across disparate scientific fields.

Humans↗

PubMed1996

Discriminative analysis of rat Sertoli and peritubular cells and their proliferation in vitro: evidence for follicle-stimulating hormone-mediated contact inhibition of Sertoli cell mitosis.

A new methodological approach using immunohistochemical markers for Sertoli cells (alpha inhibin), peritubular cells (alpha smooth muscle actin), and S-phase cells (bromodeoxyuridine; BrdU) is presented that allows an accurate and simultaneous analysis of morphogenetic and mitogenic changes occurring in vitro. Sertoli cells and peritubular cells were isolated by sequential enzymatic digestion from 7-day-old rats. Laminin, as a major component of the extracellular matrix of the seminiferous tubule, and FSH, as a hormone stimulating Sertoli cell proliferation, were tested for their ability to influence the morphology or mitotic activity of the cultured cells. After fixation, the coverslips were stained for these antigens with use of specific primary antibodies and horseradish peroxidase- or alkaline phosphatase-labeled secondary antibodies for visualization of the respective antigens with different-colored precipitates. This approach allowed us to distinguish the two cell populations, which could not be done unequivocally without the antibody staining. We scored striking changes in cell densities and cell ratios during the culture period. Peritubular cells showed a consistently higher BrdU-labeling index than Sertoli cells. While Sertoli cells were not labeled until Day 7, peritubular cells proliferated as soon as on Day 3, and their density doubled from Day 3 to Day 7. A linear negative correlation was established for Sertoli cell proliferation in response to their local density on the coverslip, indicating contact inhibition as a signal for cessation of mitosis. At high cell densities, this inhibition was partially overcome in the presence of FSH. The presence of laminin had striking effects on the morphogenetic response but only a minor influence on mitogenesis.

Animals↗

PubMed1996

The development of children's strategies on an inductive reasoning task.

This paper reports an analysis of children's cognitive strategies on an inductive reasoning task, by means of a new methodological approach. A sample of 72 children aged 6, 8 and 10 were presented with three different versions of a multidimensional discrimination learning task, which was presented in such a way as to 'optimise' their performance. Their responses were analysed in terms of 10 Strategy Components, scores on which were analysed by means of cluster analysis. Overall, the children performed at more sophisticated levels than previously found. Five Strategy Clusters representing distinct patterns of strategic behaviour were revealed. A developmental sequence was established between these patterns of strategic behaviour and, significantly, two alternative developmental routes relating to strategic style. While the results support a complex model of strategy construction, as revealed by recent research, the distinct nature of the Strategy Clusters points to a discontinuous model of strategy development. This evidence of children's differing abilities to construct and select appropriate strategies in relation to a novel task strongly supports the educational imperative of encouraging children's early use and awareness of cognitive strategies.

Aptitude↗

PubMed1994

Topographical organization of the cerebellar cortical projection to nucleus interpositus anterior in the cat.

1. A new methodological approach for detailed study of the organization of the cerebellar corticonuclear projection was evaluated in barbiturate-anaesthetized cats. Extracellular field potentials were simultaneously recorded in nucleus interpositus anterior and in the forelimb area of the C3 zone, at the cerebellar surface. On electrical and natural stimulation of the forelimb skin, the evoked positive field potentials in the nucleus and the climbing fibre field potentials in the cerebellar cortex had similar characteristics, indicating that the nuclear potentials were related to climbing fibre activity. 2. Application of a local anaesthetic to the cerebellar surface reversibly diminished the positive field potentials in the nucleus, demonstrating that the potentials were dependent on cerebellar cortical activity. It was thus concluded that the positive field potentials were mainly generated by climbing fibre-activated Purkinje cells and reflected synaptic inhibitory potentials in nuclear neurones. Accordingly, the positive field potentials in the nucleus could be used to reveal the termination area of Purkinje cells activated by a specific climbing fibre input evoked on peripheral stimulation. 3. The topographical organization of the cerebellar cortical projection to the forelimb part of nucleus interpositus anterior was then investigated by systematically mapping the cutaneous tactile and nociceptive 'receptive fields' of the positive field potentials at different sites in the nucleus. Five groups of receptive fields were distinguished and tentatively divided into a total of nineteen subgroups. 4. Each group of receptive fields corresponded to one or two of the previously described receptive field classes of climbing fibres to the C1, C3 and Y zones and was represented in a single area of the nucleus. Within each area there was an orderly representation of different receptive fields. The results suggest that microzones in the C1, C3 and Y zones with similar climbing fibre input project to a common set of neurones in nucleus interpositus anterior. 5. We propose a modular organization for the cerebellar control of forelimb movements through the rubrospinal tract. Each module would consist of a set of neurones in nucleus interpositus anterior and their afferent microzones in the C1, C3 and Y zones. A module would control a specific group of muscles and receive a homogeneous climbing fibre input related to the movement controlled.

Anesthetics, Local↗

PubMed1987

Binding and functional effects of atrial natriuretic factor in isolated rat kidney.

A new methodological approach was developed to study the relationship between specific binding and dose-response curves of the renal effects of atrial natriuretic factor (ANF) in isolated perfused rat kidneys (IK). IK were perfused with 125I-labeled and unlabeled ANF 1-28 (4 pM to 1 microM) to determine the following: 1) distribution, capacity (Cmax), and apparent affinity (S50) of specific binding of ANF 1-28 in cortex, outer medulla, and papilla and 2) dose-response curves of the effects of ANF 1-28 on renal hemodynamics and excretion of fluid and electrolytes. The kidney had a very high density of high-affinity binding sites for ANF. Cortex had greater than 90% of total binding sites (Cmax = 6.8 pmol/g tissue; S50 = 54 pM), whereas papilla had less than 2% of total binding sites with a 10-fold lower apparent affinity (S50 = 860 pM) than in cortex. ANF-induced increases in glomerular filtration rate and excretion of fluid and electrolytes were detectable at 10-100 pM and maximal effects occurred at 1-10 nM ANF. Below 1 nM there was no dissociation between the renal hemodynamic and natriuretic effects of ANF. There was a close agreement between dose-response and binding curves of ANF to cortex. Results demonstrate that binding site occupancy in kidney cortex and renal effects of ANF occur at near physiological concentrations of the hormone.

Animals↗

PubMed2005

Skiing and snowboarding injuries.

OBJECTIVE: To critically examine the literature on skiing and snowboarding injuries in children and adolescents. DATA SOURCES: Searched English language articles from: Medline, SPORTDiscus, Cumulative Index to Nursing and Allied Health Literature, Current Contents, and HealthSTAR. The table of contents for Ski Trauma and Skiing Safety Series published by the American Society for Testing and Materials were also examined. MeSH headings included: Sports, Athletic Injuries, and Accidents. Keywords used within these headings were Skiing and/or Snowboarding with focus on children, adolescents, youth, students, or age group-related comparisons. MAIN RESULTS: The patterns and rates of injury differed markedly by activity and study design. Most studies were case-series investigations providing little useful information on risk factors. Intrinsic risk factors included: lower ability, younger age, past injury, and female sex. Extrinsic risk factors were improper binding adjustment, no helmet, certain slope characteristics, and no wrist guards. The literature on the effect of activity, equipment ownership and lessons on injury risk was equivocal. CONCLUSIONS: Suggestions for injury prevention include the use of helmets and wrist guards, participation on appropriate runs for ability level, proper fit and adjustment of bindings and other equipment, and taking lessons with the goal of increasing ability and learning hill etiquette. Many areas requiring further research are identified and discussed. New methodological approaches hold promise in advancing the field of ski and snowboard injury research.

Adolescent↗

PubMed1987

Improvements to a simple Markov model of the natural history of multiple sclerosis. I. Short-term prognosis.

Follow-up data from a prognostic study done at L'Hôpital Neurologique de Lyon have been reanalyzed using a new methodologic approach. A stochastic survival model which allows the course of the disease to be described through the movement of patients from one disease state to another is presented. This approach extends previous modelling work by enabling the risk of transition between pairs of states to be written as a function of any number of discrete or continuous prognostic variables. Length of the first remission, sex, and mode of onset (mono- vs. polysymptomatic) were found to be significant prognostic indicators.

Adult↗