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Results for “functional experiments”

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At least 1,135 records · Page 63Linked to original sources
PubMed1980

Independent of etozolin elimination of kidney function. Single dose experiments in patients with renal insufficiency.

Following a single oral dose of the novel diuretic ethyl (Z)-(3-methyl-4-oxo-5-piperidino-thiazolidin-2-ylidene) acetate (etozolin, Elkapin), the plasma levels of the parent drug and its active metabolite (Z)-(3-methyl-4-oxo-5-piperidino-thiazolidin-2-ylidene) acetic acid (ozolinone) were determined by means of HPLC. In order to learn whether or not impairment of renal function influences the plasma levels of the diuretics and their elimination rate 19 patients with various degrees of reduced glomerular filtration rate were investigated. The lack of correlation between elimination half-life (HL) and creatinine clearance showed that there is no influence of kidney disease on the pharmacokinetic parameters of etozolin and ozolinone. Even in severe renal insufficiency the HL of etozolin and ozolinone did not differ from normal values, the mean HL of etozolin being 2.8 +/- 0.4 h and of ozolinone being 10.2 +/- 1.5 h. Also impairment of liver function did not signficantly alter the pharmacokinetic parameters of these diuretic agents. It is concluded that in the single dose experiments renal insufficiency does not significantly influence the metabolization of etozolin and ozolinone.

Adolescent↗
PubMed1994

Functional endoscopic sinus surgery--the South African experience.

Questionnaires were sent to 148 South African otorhinolaryngologists to ascertain their experience of functional endoscopic sinus surgery (FESS). The Messerklinger approach to FESS was followed by 87% of the surgeons who responded. In South Africa FESS is performed mainly under general anaesthesia. An incidence of 1.3% is reported in respect of major complications. Information obtained from the questionnaires describes training and supports further study. Registrars need more than knowledge and surgical experience; their skills must also be assessed by some form of certification.

Endoscopy↗
PubMed1980

[Synergistic or antagonistic interaction between dopamine and droperidol (DHB) on general hemodynamics and kidney function. An animal experiment study].

We investigated the renal effects of low and high concentrations of dopamine (4 and 10 microgram . kg-1 . min-1) in dog experiments. Dopamine increased renal blood flow, glomerular filtration rate, renal oxygen consumption and urinary excretion. These effects could not be antagonized by droperidol. In clinical doses both drugs rather act synergistically upon the cardiovascular system and renal function.

Animals↗
PubMed1998

Becoming a grandparent: a longitudinal study of expectations and early experiences as a function of sex and lineage.

First-time grandparents (N = 152) participated in a study of expectations of grandparenthood while their first grandchild was still in utero. One to 2 years after their first grandchild was born, they were asked to fill out the Thomas (1990) grandparent questionnaire again, and 103 did so. Expectations and experiences of grandparenthood were compared separating grandparents by sex and by lineage. Expectations and experiences of grandparenthood differed by both grandparent sex and lineage. In particular, grandmothers reported greater satisfaction and overall meaning in grandparenthood than grandfathers, whereas grandfathers felt more able to offer child-rearing advice to the parents. In regard to lineage, maternal grandparents were more satisfied in grandparenthood than they expected to be, whereas paternal grandparents were not.

Adult↗
PubMedDate not supplied

[The contact-free control of the functional state: the experience of its practical use].

Application of contactless control method does not create any psychological or physical discomfort for a man and allows to realize diagnostics continuously for a long time, evidently or secretly. These properties of the control determine its effective application in practice. In the paper the data are given of the studies of the functional state of a man-operator using the parameters of the eyelids movements contactlessly recorded in infra-red rays, and the results of diagnostics of patients with depression by the characteristics of their speech, recorded from the microphone. The above data are obtained in practice.

Depression↗
PubMed1993

Implicit and explicit memory for novel visual objects: structure and function.

Six experiments compared the effects of structural and functional encoding tasks on implicit and explicit memory for novel objects. Implicit memory was assessed with a possible-impossible object decision test, and explicit memory was assessed with a yes-no recognition test. Results revealed that recognition memory was higher after functional than after structural encoding tasks, whereas priming effects on the object decision test were unaffected by the same manipulations. The priming effects that were observed after functional encoding tasks could be attributed to structural analyses that are carried out in the course of making judgments about functional properties of novel objects. Results are consistent with the hypothesis that implicit memory for novel objects depends on a presemantic structural description system that can operate independently of episodic memory.

Adult↗
PubMed1989

Signal uncertainty and psychometric functions in profile analysis.

Experiment 1 was conducted to compare the effects of signal frequency uncertainty on the detection of a change in spectral shape and on the detection of a tone in wideband noise. Results indicate that for both tasks the uncertainty effect was small, being on average about 3 dB. In a second experiment, psychometric functions were measured for the detection of changes in the spectral shape of multicomponent complexes. Psychometric functions for profile tasks have a 25-dB range and are similar to those measured for the detection of an increment in the level of a single sinusoid. These psychometric functions are different from those found when detecting a signal in noise, which typically have a 10-dB range. Three equations for the shape of the psychometric functions were compared. The difference in the resulting fits was small, thus preventing an unambiguous choice of functional form.

Acoustic Stimulation↗
PubMed1981

Reaggregation of rat gonadal cells in vitro: experiments on the function of H-Y antigen.

Dispersed cells of the gonads of newborn rats reaggregate histotypically in rotation culture. Ovarian cells form follicles, while testicular cells organize tubuli. When testis cell supernatant is added to ovarian cells, they form tubulus-like structures. This effect is impeded by simultaneous addition of monoclonal anti-H-Y antibody. It is concluded that H-Y antigen is the active factor of testis cell supernatant that induces sex-reversal of ovarian cells in vitro. The reverse experiment, i.e., exposure of testicular cells to anti-H-Y antiserum, does not result in the organization of follicular structures. These findings are consistent with the view that H-Y antigen is involved in testis differentiation by inducing testis cell-specific functions, rather than by cross-linking cells.

Animals↗
PubMed1994

Effects of breakfast and caffeine on cognitive performance, mood and cardiovascular functioning.

Two experiments examined the effect of breakfast (1.89 MJ) and caffeine (4 mg/kg) on cognitive performance, mood and cardiovascular functioning. In the first experiment, breakfast had no effect on performance of sustained attention tasks, but it increased pulse rate and influenced mood. The mood effects after breakfast differed between a cooked breakfast and a cereal/toast breakfast. In contrast to the effects of breakfast, this relatively high dose of caffeine improved performance of the sustained attention tasks, increased blood pressure and increased mental alertness. In the second experiment, effects of a breakfast and caffeine on mood and cardiovascular functions confirmed the results of the first study. The breakfast improved performance on free recall and recognition memory tasks, had no effect on a semantic memory task and impaired the accuracy of performing a logical reasoning task. In contrast to this, caffeine improved performance on the semantic memory, logical reasoning, free recall and recognition memory tasks. Overall, these results show that breakfast can improve performance in some but not all cognitive tasks and that these changes are very different from those observed after lunch, and those produced by caffeine.

Affect↗
PubMed1998

Interpreting functional imaging studies in terms of neurotransmitter cycling.

Functional imaging experiments, in particular positron-emission tomography and functional magnetic resonance imaging, can be analyzed either in psychological terms or on the basis of neuroscience. In the usual psychological interpretation, stimulations are designed to activate specific mental processes identified by cognitive psychology, which are then localized by the signals in functional imaging experiments. An alternate approach would be to analyze experiments in terms of the neurobiological processes responsible for the signals. Recent in vivo 13C NMR measurements of the glutamate-to-glutamine neurotransmitter cycling in rat and human brains facilitate a neuroscientific interpretation of functional imaging data in terms of neurobiological processes since incremental neurotransmitter flux showed a 1:1 stoichiometry with the incremental rate of glucose oxidation. Because functional imaging signals depend on brain energy consumption, a quantitative relationship can be established between the signal (S) and the specific neurochemical cerebral neurotransmitter activity (N) of glutamate-to-glutamine neurotransmitter cycling. The quantitation of neuronal activity proposed has implications for the psychological design and interpretation of functional imaging experiments. Measurements of the neurotransmitter cycling flux at rest in functional imaging experiments suggest that performing cognitive tasks and sensory stimulations increases neurotransmitter cycling by only 10-20%. Therefore it cannot be assumed that reference state activities are negligible, nor that they are constant during stimulation.

Animals↗
PubMed1992

Telescience testbed: operational support functions for biomedical experiments.

A telescience testbed was conducted to study the methodology of space biomedicine with simulated constraints imposed on space experiments. An experimental subject selected for this testbedding was an elaborate surgery of animals and electrophysiological measurements conducted by an operator onboard. The standing potential in the ampulla of the pigeon's semicircular canal was measured during gravitational and caloric stimulation. A principal investigator, isolated from the operation site, participated in the experiment interactively by telecommunication links. Reliability analysis was applied to the whole layers of experimentation, including design of experimental objectives and operational procedures. Engineering and technological aspects of telescience are discussed in terms of reliability to assure quality of science. Feasibility of robotics was examined for supportive functions to reduce the workload of the onboard operator.

Aerospace Medicine↗
PubMed2002

Pulmonary function changes in long-term survivors of chronic myelogenous leukemia after allogeneic bone marrow transplantation: a Taiwan experience.

Pulmonary function in 42 patients with chronic myelogenous leukemia (CML) was tested before and after HLA-matched (39 related, 3 unrelated) allogeneic bone marrow transplantation (BMT) between 1985 and 1999. Pulmonary function tests (PFTs) including ventilatory capacity, lung volumes, and diffusion capacity for carbon monoxide (DLCO) were performed before and 3, 6, 12, and 24 months after BMT, and every 12 months thereafter. Possible pre- and post-BMT risk factors were evaluated for their influence on pulmonary function. Patients were divided into two groups according to their survival duration for more than 12 months or not. Pretransplant PFTs were essentially normal except for mild reduction in DLCO values in the short-term survival group. Overall pulmonary function changes revealed persistent and significant decrease of forced vital capacity (FVC) and DLCO values after BMT. The DLCO values reached abnormal levels (< 80%) and showed a trend of incomplete recovery. Decrease of forced expiratory volume in the first second (FEV1) and vital capacity were also noted but the FEV1/FVC ratio remained within normal limits after BMT. Transient fall of total lung capacity after BMT was noted. However, its values did not reach abnormal levels such as to cause restrictive ventilatory impairment. Possible risk factors including gender, smoking, bronchiolitis obliterans, acute and chronic graft-versus-host disease (GVHD) were found to have significant influences on posttransplant pulmonary function changes by multiple regression analysis. Most patients except those who developed bronchiolitis obliterans were clinically asymptomatic. Development of bronchiolitis obliterans was the most important factor to cause both clinical symptoms and impaired pulmonary function. In summary, pulmonary function changes before and after HLA-matched allogeneic BMT in long-term survivors of CML only showed modest dysfunction. The primary negative presentation with the development of oxygenation defect had no clinical significance in most patients. The influences on the impairment of pulmonary function were multifactorial.

Adolescent↗
PubMed2006

Does pycnogenol intensify the efficacy of acetylsalicylic acid in the inhibition of platelet function? In vitro experience.

INTRODUCTION: Some compounds of herbal origin, such as Pycnogenol (PYC), have been considered as an aid in antiplatelet therapy. Pycnogenol, a French maritime pine bark extract, is a complex mixture of polyphenols that has the ability to reduce human smoking-induced platelet aggregation. The aim of this study was to evaluate the in vitro ability of PYC to improve the efficacy of acetylsalicylic acid (ASA) in the inhibition of platelet function. MATERIAL/METHODS: Whole blood, anticoagulated with hirudin, was drawn from 38 volunteers (40.4+/-13.8 years old) and incubated with PYC (10, 50, 100 microg/ml) or/and ASA (25, 100 micromol/l) for 20 min at RT.PYC was dissolved in water (water-PYC group, n=20) or ethanol (ethanol-PYC group, n=18). To investigate platelet functions, PFA-100 closure-time determination, whole-blood electrical aggregation (WBEA), and PRP aggregation were employed. Collagen (1 microg/ml) and ADP (5 micromol/l) were used as platelet agonists. RESULTS: A compounding effect of ASA and PYC to inhibit platelet function recorded in collagen-induced aggregation in PRP was observed, but only when ethanol-dissolved PYC was used. The inhibitory effect of PYC (alone) was most profound in platelets activated with ADP. At all concentrations, PYC significantly inhibited platelet aggregation only in the ethanol-PYC group. CONCLUSIONS: It was found that under in vitro conditions, ethanol-dissolved PYC deepened the efficacy of ASA to inhibit platelet function. This study confirmed the direct and compounding (with ASA) inhibitory effect of PYC on platelets. These observations encourage the concept that the combined use of ASA and PYC may be beneficial in patients with impaired response to ASA therapy.

Adult↗
PubMed2005

How patients experience progressive loss of visual function: a model of adjustment using qualitative methods.

BACKGROUND: People with retinitis pigmentosa (RP) experience functional and psychological challenges as they adjust to progressive loss of visual function. The authors aimed to understand better the process of adjusting to RP in light of the emotional suffering associated with this process. METHODS: Adults with RP were recruited from the Foundation Fighting Blindness and the Wilmer Eye Institute in Baltimore. Focus groups and semistructured interviews addressed the process of adjusting to RP and were audiotaped and transcribed. The transcripts were analysed qualitatively in order to generate a model of adjustment. RESULTS: A total of 43 individuals participated. It was found that, on diagnosis, people with RP seek to understand its meaning in their lives. Mastering the progressive functional implications associated with RP is contingent upon shifting personal identity from a sighted to a visually impaired person. In this sample, six participants self identified as sighted, 10 self identified as in transition, and 27 self identified as visually impaired. This adjustment process can be understood in terms of a five stage model of behaviour change. CONCLUSIONS: The proposed model presents one way to understand the process of adjusting to RP and could assist ophthalmologists in meeting their moral obligation to lessen patients' suffering, which arises in the course of their adjustment to progressive loss of visual function.

Adaptation, Psychological↗
PubMedDate not supplied

Rise, fall and resurrection of chromosome territories: a historical perspective. Part II. Fall and resurrection of chromosome territories during the 1950s to 1980s. Part III. Chromosome territories and the functional nuclear architecture: experiments and models from the 1990s to the present.

Part II of this historical review on the progress of nuclear architecture studies points out why the original hypothesis of chromosome territories from Carl Rabl and Theodor Boveri (described in part I) was abandoned during the 1950s and finally proven by compelling evidence forwarded by laser-uv-microbeam studies and in situ hybridization experiments. Part II also includes a section on the development of advanced light microscopic techniques breaking the classical Abbe limit written for readers with little knowledge about the present state of the theory of light microscopic resolution. These developments have made it possible to perform 3D distance measurements between genes or other specifically stained, nuclear structures with high precision at the nanometer scale. Moreover, it has become possible to record full images from fluorescent structures and perform quantitative measurements of their shapes and volumes at a level of resolution that until recently could only be achieved by electron microscopy. In part III we review the development of experiments and models of nuclear architecture since the 1990s. Emphasis is laid on the still strongly conflicting views about the basic principles of higher order chromatin organization. A concluding section explains what needs to be done to resolve these conflicts and to come closer to the final goal of all studies of the nuclear architecture, namely to understand the implications of nuclear architecture for nuclear functions.

Animals↗