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At least 397 records · Page 22Linked to original sources
PubMed1983

From metapsychology to molecular biology: explorations into the nature of anxiety.

Through the use of animal models, specific forms of mentation can now be explored on the cellular and molecular levels. Chronic anxiety and anticipatory anxiety in humans are closely paralleled by two forms of learned fear in the sea snail Aplysia: sensitization and aversive classical conditioning. In Aplysia's simple nervous system it is possible to delineate how the two forms are acquired and maintained. Both rely on the mechanisms of presynaptic facilitation. An augmented form of presynaptic facilitation accounts for the associative component of conditioning. These findings suggest that a surprisingly simple set of cellular and molecular mechanisms in various combinations may underlie a wide range of both adaptive and maladaptive behavioral modifications.

Animals↗
PubMed2005

Flow limitation and dynamic hyperinflation: key concepts in modern respiratory physiology.

Fashions in ideas, like clothes, come and go. From approximately 1950-1980, physiological research was seen as the key discipline in understanding lung disease and was at the cutting edge of pulmonary science. Subsequently, its importance has been down played amid a widely accepted but unfounded assumption that we now have a perfect working understanding of the physiological behaviour of the respiratory system in health and disease. Although it seems improbable that completely new disciplines within respiratory physiology will emerge with fundamentally different ways of describing the mechanical or gas exchanging function of the lung, advances in computing and new observations in disease have highlighted previously unsuspected physiological abnormalities that have changed the way we view lung disease and the interface between disordered lung mechanics, symptomatology and disability. This is especially true for the two related physiological concepts of expiratory flow limitation and dynamic hyperinflation, which are now being taken from the physiological laboratory to the bedside with dramatic effect. Each arises from well-established theoretical and practical observations first made 40 yrs ago and now adapted to a range of settings, particularly in the field of obstructive lung disease. This review focuses on how these conditions are defined and assessed and what evidence there is that they might be important in lung disease.

Airway Resistance↗
PubMed2006

Genome-wide transcriptional analysis of temperature shift in L. interrogans serovar lai strain 56601.

BACKGROUND: Leptospira interrogans is an important mammalian pathogen. Transmission from an environmental source requires adaptation to a range of new environmental conditions in the organs and tissues of the infected host. Several studies have shown that a shift in culture temperature from 28 degrees C to 37 degrees C, similar to that encountered during infection of a host from an environmental source, is associated with differential synthesis of several proteins of the outer membrane, periplasm and cytoplasm. The whole genome of the Leptospira interrogans serogroup Icterohaemorrhagiae serovar lai type strain #56601 was sequenced in 2003 and microarrays were constructed to compare differential transcription of the whole genome at 37 degrees C and 28 degrees C. RESULTS: DNA microarray analyses were used to investigate the influence of temperature on global gene expression in L. interrogans grown to mid-exponential phase at 28 degrees C and 37 degrees C. Expression of 106 genes differed significantly at the two temperatures. The differentially expressed genes belonged to nine functional categories: Cell wall/membrane biogenesis genes, hemolysin genes, heat shock proteins genes, intracellular trafficking and secretion genes, two-component system and transcriptional regulator genes, information storage and processing genes, chemotaxis and flagellar genes, metabolism genes and genes with no known homologue. Real-time reverse transcription-PCR assays confirmed the microarray data. CONCLUSION: Microarray analyses demonstrated that L. interrogans responds globally to temperature alteration. The data delineate the spectrum of temperature-regulated gene expression in an important human pathogen and provide many new insights into its pathogenesis.

Bacterial Proteins↗
PubMed1995

Parental perceptions of procedure-related distress and family adaptation in childhood leukemia.

Child and parental distress related to lumbar punctures and bone marrow aspirates and general family adaptation are evaluated in a cross-sectional study of children currently in treatment with leukemia in first remission (N = 70). A parental self-report measure developed for this study--the Perception of Procedures Questionnaire (PPQ)--yielded three factors: (a) parental satisfaction, (b) parental distress or involvement, and (c) child distress. Data from the PPQ showed high levels of both satisfaction and distress in the context of invasive procedures. Data from standardized measures of family adaptation demonstrated a range of functioning. Analyses by length of time since diagnosis indicated that parental distress remains stable over the course of treatment. The data are discussed with respect to the newly developed measure of parental procedures (the PPQ) and the need for research in this field that provides an integration of procedural distress with parent and family perceptions and adjustment.

Adolescent↗
PubMed1984

Additivity of dichromatic color matches to short-wavelength lights.

The additivity of color matches to short-wavelength lights was examined in observers who behaved as red-green dichromats under the stimulus conditions used. Color matches were obtained at several luminance levels and on several different adapting backgrounds. The range of mixtures acceptable as a match and the midpoint of this range varied considerably over different conditions. However, for each observer, a set of mixtures that remained a match under all conditions could always be found. Results suggest that the additivity laws hold for these observers in the sense that there is a color match that remains a match under all conditions.

Color Perception↗
PubMed2006

Working with oxygen and oxidative stress in vitro.

Oxygen has a profound influence on the behavior of many cell types, including trophoblast. The effects are mediated in part through the generation of oxygen free radicals, which act as signaling molecules. Because of their high reactivity, free radicals are, however, potentially damaging to a wide range of biomolecules, and if concentrations exceed homeostatic levels then cellular oxidative stress results. Responses of tissues to changes in oxygen concentration may therefore range from physiological adaptations to pathological insults. Placental development is heavily modulated by the prevailing oxygen concentration, and understanding the mechanisms involved is clearly important. Equally, trophoblastic oxidative stress plays a key role in the pathogenesis of pregnancy complications such as miscarriage and preeclampsia. This chapter describes techniques by which the effects of oxygen and oxidative stress on placental tissues can be systematically investigated in vitro.

Female↗
PubMed1999

Valspodar: current status and perspectives.

Valspodar (Amdray, SDZ PSC 833) is derived from cyclosporin, but lacks the immunosuppressive and most of the collateral activities of cyclosporin A (CsA, Sandimmune, Neoral); it exhibits an enhanced capacity to chemosensitise tumour cells showing the classical type multiple drug-resistance (MDR) associated with MDR1 P-glycoprotein (Pgp) overexpression. This valspodar-mediated chemosensitisation of MDR tumour cells is reviewed with regard to its mechanism of inhibition on Pgp flippase function, and its potential inhibition of anticancer drug (ACD) metabolisation by CYP3A enzymes is discussed. Potent inhibition of the membranous and cytoplasmic detoxification mechanisms expressed by cells at the absorption and clearance borders in the body by valspodar results in the many pharmacokinetic interactions with other drugs that are substrates of either, or both, Pgp and CYP classes of detoxifying enzyme. In view of the present ability to restrict oral bioavailability of valspodar within a narrow range, and to adapt adequately the chemotherapeutic dosages to achieve their equivalent exposure in the presence or absence of valspodar, current clinical data on its efficacy and safety permit optimism for ongoing Phase III trials. The potential of valspodar to increase exposure or to modulate the biodistribution of other chemotherapeutics, such as HIV protease inhibitors to the brain, is further evoked, as this might become another application of the new drug. This evaluation of valspodar compared to CsA attempts to interpret its mechanisms of action, rather than to serve as a complete and comparative repertoire of all published preclinical and clinical data.

Journal Article↗
PubMed2005

Electrical coupling between interneurons with different excitable properties in the stratum lacunosum-moleculare of the juvenile CA1 rat hippocampus.

Electrical coupling among GABAergic interneurons is believed to play an essential role in shaping synchronized brain network activity related to cognition and behavior. We have studied the rules governing the electrical coupling between hippocampal interneurons located in stratum lacunosum-moleculare of the CA1 hippocampus. The most frequently recorded interneuron subtype had short multipolar dendrites and a dense local axonal arborization, typical of neurogliaform cells. Electrical excitability in this class of interneurons was heterogeneous. Although injection of small current steps evoked late spiking, larger steps triggered different types of firing patterns. Trains of action potentials ranged from clearly adapting to highly irregular, with clustered or mostly regular spikes. Electrotonic and action potentials could be propagated to the coupled cells; the coupling coefficient for electrotonic signals was 0.035, which compared with 0.005 for action potentials. Electrical coupling was reversibly blocked by application of carbenoxolone. Multiple simultaneous recordings indicated that interneurons with similar and different firing patterns were electrically coupled. This visual impression was quantitatively confirmed by principal component analysis applied to variables related to membrane excitability. In fact, the probability of finding electrically coupled neurons in our sample was not dependent on the excitable properties of the cells tested and was approximately 0.34. The presence of diffuse electrical coupling among hippocampal interneurons of stratum lacunosum-moleculare with different excitability is a novel finding with important implications. For example, the promiscuity of electrical connections may endow inhibitory networks with a large degree of flexibility and regulate the computational power of the hippocampus during different synchronized states.

Action Potentials↗
PubMed2026

Forty years in the field: reproductive biotechnologies shaping genetic progress in cattle in France.

Over the past four decades, reproductive biotechnologies have profoundly transformed cattle breeding by accelerating genetic progress and enabling the dissemination of elite genetics. In this article, I present a perspective based on more than 40 years of practical experience in embryo technologies within Auriva-Elevage, a cooperative organization serving 30,000 farmers in southern France. The development of embryo transfer in France was closely linked to genetic and sanitary challenges, particularly the introduction of North American Holstein genetics and the restrictions on live animal imports due to infectious diseases such as Infectious Bovine Rhinotracheitis. These constraints stimulated the development of national expertise in embryo transfer. Over the years, our team has implemented and adapted a wide range of reproductive technologies including in vivo embryo production and embryo transfer, cryopreservation, embryo sexing, ovum pick-up (OPU), in vitro embryo production (IVP), embryo biopsy, genomic evaluation of embryos, and laser-assisted biopsy techniques. The genomic revolution dramatically increased the strategic value of OPU-IVP for the rapid multiplication of elite donor females. In addition to technological developments, the success of these programs has depended heavily on internal training, collaboration with national organizations such as ELIANCE (previously UNCEIA, ALLICE) and research institutes including INRAE and Toulouse veterinary school, as well as strong international exchanges through scientific networks. Practical examples such as the use of embryo biopsy to prevent genetic diseases demonstrate the applied value of these technologies in breeding programs. This review highlights the technical evolution, organizational structures, and human expertise that have shaped the implementation of reproductive biotechnologies in cattle breeding and discusses the importance of anticipating future needs to ensure continued genetic progress.

OPU-IVP↗
PubMed2001

Using psychological assessment and therapeutic strategies to enhance well-being.

OBJECTIVE: To provide an overview of the psychological assessment; results from studies examining psychological issues among individuals with craniofacial anomalies (CFA) and other chronic conditions; resilience; and therapeutic strategies to enhance psychological well-being. CONCLUSIONS: The literature on chronic conditions and findings from studies with people having CFA and their families demonstrate a range of effective adaptation patterns and strategies to enhance issues having an impact on quality of life.

Adaptation, Psychological↗
PubMed1998

Changes in peri-implant tissues subjected to orthodontic forces and ligature breakdown in monkeys.

The aims of this investigation were to histologically evaluate in monkeys the effect of a repetitive mechanical trauma alone on the peri-implant tissues, and the effect of a repetitive mechanical trauma in combination with ligature-induced peri-implantitis on the peri-implant tissues. The study used 5 male cynomolgus monkeys. Prior to the start of the study, all premolars and the first and second molars in the mandible were extracted. After a healing period of 12 weeks, following tooth extraction, split/full thickness flaps were elevated on both sides of the mandible in order to expose the bony ridge. Four implants, of 3.75 mm in diameter and 7 mm in length, were then inserted on each side and the flaps were readapted and sutured in place. Following a healing period of 16 weeks, the second stage procedure was performed, impressions were taken, and custom-made crowns using a non-precious metal alloy were fabricated and inserted on all implants 4 weeks after abutment connection. At the same time peri-implantitis was induced on one side of the mandible by placing plaque-retentive ligatures around the implants. On the other side, an oral hygiene program consisting of thrice weekly brushing with a toothbrush and flour of pumice mixed with 2% chlorhexidine was initiated. Four months later, a repetitive mechanical trauma was initiated on implants 1 and 2 on both sides in the mandible. Consequently, a split mouth design was obtained: 1) test 1=ligature-induced peri-implantitis alone (LPNO); 2) test 2=ligature-induced peri-implantitits with a repetitive mechanical trauma (LPMT); 3) test 3=healthy peri-implant tissues with a repetitive mechanical trauma (MT); and 4) control (NO)=healthy peri-implant tissues with no repetitive mechanical trauma. Following 16 weeks of repetitive mechanical trauma the animals were sacrificed. Histologic observations and computed-assisted histometric and histomorphometric analyses were performed to determine the amount of peri-implant bone loss and the percentage of direct mineralized bone-to-implant contact around each endosseous oral implant. Histologically, all implants yielded osseointegration at the light microscopic level. There was a significant difference regarding the mean direct mineralized bone-to-implant contact length as a fraction of the total implant length between the healthy (i.e., MT and NO) and diseased sites (i.e., LPNO and LPMT) (P < 0.05). When comparing the percent of direct mineralized bone-to-implant contact for the 2 best threads of each implant and group, no significant difference (P=0.675) could be detected. Under the conditions of this study, the repetitive mechanical trauma showed no histologic effect on the peri-implant bone loss neither in healthy nor in diseased implant sites. The effects of excessive loading on osseointegration are presently not clearly understood. The key problem seems to be the determination when loading on implants exceeds the physiological range of bone adaptation which may then cause implant failure. Further research to elucidate this problem is essential.

Adaptation, Physiological↗
PubMed2005

Physical and cognitive activity and exercise for older adults: a review.

Age-related reduction in musculoskeletal, cardiovascular, and central nervous system resilience can result in wide-ranging limitations in adaptive capacity associated with negative outcomes such as cognitive decline, increased risk of cardiovascular disease, mobility problems, and increased incidence of debilitating falls. This article reviews the benefits of both cognitive and physical activity within the broad context of multiple system resilience in adult aging. Research on a unique form of combined physical/cognitive exercise, Tai Chi Chuan, is presented. The relationship between physiological and psychological gain associated with an activity intervention program is discussed in light of principles of rehabilitation, intervention compliance, subjective and objective gain, and the hypothesized value of combining physical exercise, cognitive exercise, and relaxation into a single program designed to promote resilience in older adults.

Accidental Falls↗
PubMed2004

A probabilistic and interactive decision-analysis system for unruptured intracranial aneurysms.

OBJECT: The goal in this study was to develop an interactive, probabilistic decision-analysis system for clinical use in the decision to treat or observe unruptured intracranial aneurysms. Further goals were to enable users of the system to adapt decision-analysis methods to individual patients and to provide a tool for interactive sensitivity analysis. METHODS: A computer program was designed to model the outcomes of treatment and observation of unruptured aneurysms. The user supplies probabilistic estimates of key parameters relating to a specific patient and nominates discount rate and quality of life adjustments. The program uses Monte Carlo discrete-event simulation methods to derive probability estimates of the outcomes of treatment and observation. Results are expressed as summary statistics and graphs. Discounted quality-adjusted life years are graphed using survival methods. Hierarchical simulations are used to enable investigators to perform probabilistic sensitivity analysis for one or multiple parameters simultaneously. The results of sensitivity analysis are expressed in graphs and as the expected value of perfect information. The system can be distributed and updated using the Internet. CONCLUSIONS: Further research is required into the benefits of clinical application of this system. Further research is also required into the optimum level of complexity of the model, into the user interface, and into how clinicians and patients are likely to interpret results. The system is easily adaptable to a range of medical decision analyses.

Confidence Intervals↗
PubMed1981

Dwarfism in diverse genetic backgrounds. 4. Effects of dietary energy.

The interactions in the response of dwarf and normal genotypes to dietary energy were studied in lines of chickens divergently selected for high or low juvenile body weight. The genetic background of the dwarf genotype significantly affected body weights, egg production, and egg quality. The dietary energy levels used did not significantly affect these traits or the differences due to genetic background. Dwarf chickens were able to adapt to wide ranges of dietary energy when the diets contained sufficient crude protein.

Animal Feed↗
PubMed1991

Effect of PEEP-valve placement on function of a home-care ventilator.

BACKGROUND: The addition of a PEEP valve to the circuit of a home-care ventilator like the Aequitron LP-6 can be viewed as a consumer modification of the system. We sought to determine the effect that such a modification would have on ventilator function. METHODS & MATERIALS: Part 1. We tested the effect of PEEP level and PEEP-valve position on volume delivered at the ventilator Y-adapter, over a range of tidal volumes. Part 2. We held tidal volume, frequency, and inspiratory time constant, and varied PEEP level and PEEP-valve position to test the effect of PEEP-valve position on pressures measured at the ventilator outlet, patient-Y, and within the exhalation-valve pressurization line. RESULTS: Conventional placement of the PEEP value (distal to, or 'after,' the exhalation valve) in the LP-6 ventilator circuit resulted in statistically significant and potentially clinically important decreases in the volumes delivered to the patient at some ventilator settings. Proximal placement of the PEEP valve (proximal to, or 'before,' the exhalation valve) resulted in consistent volumes delivered to the patient at all levels tested, without changing the ventilatory performance characteristics of the ventilator as reflected by pressure waveforms. CONCLUSION: We recommend that appropriate observations and measurements be made to verify system function before a home-care ventilator modified to provide PEEP is applied to the patient.

Evaluation Studies as Topic↗
PubMed1997

Medical instruments in the Roman world.

By the beginning of the 1st century AD Roman medical instruments had begun to acquire the distinctive forms which they were to retain, more or less unchanged, for the next half millennium. They were carefully-designed, highly-crafted precision tools well-adapted to the range of surgical interventions and operations described in the contemporary medical texts. Their versatility and multiplicity of function is discussed, as also is the evidence derived from apparently complete instrumentaria, which sheds light on the form of medical practise undertaken by the people who used them.

Equipment and Supplies↗
PubMed2002

[Psychological peculiarities in adolescent patients with tuberculosis].

The paper presents the results of psychological examination in 110 adolescent patients with respiratory tuberculosis and 89 healthy adolescents aged 13 to 17 years. Most adolescent patients were found to be highly anxious personalities, they were all diagnosed as having accentuation of character. The adolescent patients differed from healthy individuals by inadequate communicability, sensitive, liability to accumulation of negative emotions, by bad need for support and feelings to be taken hard, by marked internal strain and yearning for showing his/her individuality. This also had led to the lower behavioral range, made social adaptation difficult, promoted the susceptibility to stress exposure, and increased a risk for a disease. The psychological peculiarities found may be factors that predispose to tuberculosis.

Adaptation, Psychological↗
PubMed1992

[Better listening, better information, better teaching. Lessons of our incompetence].

Short excerpts of conversations held during medical consultations permit analysis of a whole range of poorly adapted attitudes and thus demonstrate the possibility for improvement of affective contact, confidence and efficacy. It is recommended to: listen more attentively, avoid interruptions, excuses, simplifications, interpretations and premature information and to learn to repeat the flow of thoughts of the patient; inform more adequately without usage of medical terminology, abstain from confused explications, frequent change of subject, imprecision and attitudes forcing the patient into an inferior role; improve teaching of the patient by proposing distinct goals and by inviting him to find solutions to his problems by learning from errors, this without patronising and under consideration of the attitude of the patient towards his disease.

Attention↗