Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “functional”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
PubMed2003

Estimation of the Hemodynamic Response Function in event-related functional MRI: directed acyclic graphs for a general Bayesian inference framework.

A convenient way to analyze BOLD fMRI data consists of modeling the whole brain as a stationary, linear system characterized by its transfer function: the Hemodynamic Response Function (HRF). HRF estimation, though of the greatest interest, is still under investigation, for the problem is ill-conditioned. In this paper, we recall the most general Bayesian model for HRF estimation and show how it can beneficially be translated in terms of graphical models, leading to (i) a clear and efficient representation of all structural and functional relationships entailed by the model, and (ii) a straightforward numerical scheme to approximate the joint posterior distribution, allowing for estimation of the HRF, as well as all other model parameters. We finally apply this novel technique on both simulations and real data.

Adolescent↗
PubMed1987

The construction of a simultaneous functional order in nervous systems. III. The influence of environmental constraints on the resulting functional order.

In a previous paper (Part I) we introduced a model that constructs a simultaneous functional order in a set of neuronal elements by monitoring the coincidences in their signal activities (the so-called coincidence-model). The simultaneous signal activity in a neural net will be constrained both by its physical restrictions and by environmental constraints. In this paper we present the results of simulation experiments that were performed to study the influence of environmental constraints on the resulting functional order in a set of neural elements corresponding to a one-dimensional detector array. We show that the coincidence-model produces a functional order that encodes the physical constraints of the environment. Moreover, we demonstrate that the signal activity in the neural net (the "perceptions") can be related to events in the outer world. We provide some examples to demonstrate that our model may prove useful to gain insight into certain developmental disorders.

Algorithms↗
PubMed1989

Immunosuppression in experimental cryptococcosis in rats: modification of macrophage functions by T suppressor cells. Macrophages functions in cryptococcosis.

The influence of lymphocytes on the modulation of macrophage functions in altered immune states induced by Cryptococcus neoformans infection in rats has been investigated. In this report we observed a decrease of 'in vitro' phagocytic activity by peritoneal cells (PC) from rats that received T suppressor cells induced by cryptococcal infection, against both the same microorganism that stimulated this suppressor population (p less than 0.05) and another non-pathogenic primary yeast (Candida tropicalis), (p less than 0.02). The microbicide function of the PC from these animals present a significant decrease in challenge by C. tropicalis (p less than 0.002) when compared with PC from animals transferred with T normal cells. The transference of T suppressor cells induced by cryptococcal infection in animals immunized with human serum albumin-complete Freund's adjuvant (HSA-CFA) produces a significant alteration of the phagocytosis to HSA-human red cells (HSA-HRC) when compared with the phagocytosis observed in animals that received T normal cells or the phagocytosis of normal animals (p less than 0.001). We could also observe that the DTH to HSA studied during 30 days was negative in rats transferred with PC sensitizated with HSA and treated with suppressor T cells, when compared with the DTH response of animals transferred with PC-HSA cocultured with normal cells (p less than 0.05 21st day). The data presented in this paper illustrated that following infection of rats with C. neoformans there is a change in some population of accessory cells behavior reflected by the modification of several functions, such as phagocytosis, lytic activity and antigen presentation.

Animals↗
PubMed1986

Pharmacokinetics of trimazosin and its effects on blood pressure, renal function and proteinuria during short-term therapy of patients with impaired renal function and hypertension.

The kinetics and short-term (10 weeks) effects of trimazosin, an alpha 1-adrenoreceptor antagonist, on renal function and blood pressure in patients with moderate chronic renal insufficiency and hypertension, have been studied for the first time. Eight patients in whom the blood pressure was not normalized with a diuretic alone underwent pharmacokinetic studies and assessment of the renal function during a 10-week period of trimazosin therapy. Trimazosin significantly lowered blood pressure (recumbent and upright) without significantly altering renal function. Renal vascular resistance was decreased by 14%. Fractional sodium excretion, proteinuria and laboratory serum tests remained unchanged. Neither body weight nor pulse rate were affected. Moderate renal insufficiency did not modify the pharmacokinetics of the drug. Thus, trimazosin, as second-step antihypertensive agent, appeared to be safe and effective in patients with moderate renal insufficiency and hypertension, without exerting favourable or adverse renal effects during short-term therapy.

Adult↗
PubMed1992

Preferential expression and activity of multidrug resistance gene 1 product (P-glycoprotein), a functionally active efflux pump, in human CD8+ T cells: a role in cytotoxic effector function.

The multidrug resistance gene 1 (mdr 1) product, the P-glycoprotein (Pgp), is a 170-kD transmembrane transport protein, whose overexpression is associated with multidrug resistance in cancer cells and in chloroquine-resistant Plasmodium falciparum infection. In this study we show that normal freshly isolated human lymphocytes express low levels of mdr 1 mRNA and membrane Pgp. Although Pgp is expressed in both CD4+ and CD8+ T cells, it is preferentially expressed in CD8+ T cells. Activation of T lymphocytes with phytohemagglutinin leads to an amplification of both mdr 1 mRNA and membrane Pgp in T cells. P-glycoprotein in T cells is a functionally active efflux pump as demonstrated by decreased retention of rhodamine-123 and its increased accumulation by cyclosporin A, an inhibitor of Pgp function. In addition, MRK-16 antibody increased accumulation of Rh123 in CD8+ T cells. Furthermore, MRK16 anti-P-glycoprotein monoclonal antibody, in a concentration-dependent manner, inhibited T lymphocyte-mediated cytotoxicity. These data suggest a physiologic role of P-glycoprotein in cytotoxic T-lymphocyte effector function.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Anorectal anomalies: anorectal manometric function and anal endosonography in relation to functional outcome.

To assess the relation between continence and the manometric and endosonographic state of the anorectal segment after surgery for anorectal anomalies (ARA), 33 adolescents operated upon for ARA and 14 controls were examined. Seventeen patients had low and 16 intermediate or high ARA. Fecal continence was recorded, and anal canal manometry was performed by microtransducer. The sphincter muscle complex and its relation to the anal opening was visualized by anal endosonography (ES). Ten patients had perfect continence, 10 had staining, and 13 had soiling. The anal canal resting and squeeze pressures were significantly different in all three groups, and continence function was significantly correlated to anal canal pressures. By anal ES, the internal (IAS) and the external anal sphincters (EAS) were identified with various amounts of scar tissue in all patients. In patients with high or intermediate anomalies the IAS was missing in the lower part of the anal canal, and abundant scar tissue was identified in the EAS in all patients. In patients with good continence function, the EAS was better preserved than in patients with major incontinence. The position of the anus in the EAS muscle complex was assessed, and varying degrees of eccentrically placed anal canals were identified. Continence function after surgery for ARA is thus correlated to anal canal pressures and ES images. ES, which is painless and suitable for use in children, is a valuable tool for assessing perianal structures, and the findings may serve as a helpful guide for corrective surgery.

Adolescent↗
PubMed1977

[Carbenicillin induced disturbance of platelet function: a study in patients with normal renal function (author's transl)].

After therapeutic doses of carbenicillin (3X10 g/24 h) prolongation of bleeding time, measured according to Ivy, was observed (median time prior to therapy 4 min 08 s-4 min 18 s; 24 h after therapy 15-20 min; 72 h after therapy greater than 30 min) in 5 patients with normal renal function and 2 patients with slight impairment of renal function (Ccr60-70 mlX1.73 m(2)). Prolongation of bleeding time was observed at serum concentrations between 13 and 180 microgram/carbenicillin/ml. After carbenicillin was withdrawn, prolongation of bleeding time was demonstrable for 4 days, i.v. even after the drug had been eliminated completely by urinary excretion. Higher doses of carbenicillin caused more severe disturbances of platelet function. The finding of prolonged bleeding time after carbenicillin may have clinical relevance (e.g. interaction with other anticoagulants, p.o. wound bleeding, gastro-intestinal hemorrhage, thrombopenia).

Adult↗
PubMed1996

Gonadotrophin and free alpha-subunit secretion in patients with acromegaly and clinically non-functioning pituitary tumors: anterior pituitary function and the effect of thyrotrophin-releasing hormone.

The effect of the tumor size on the anterior pituitary hypofunction is analyzed in 29 patients with acromegaly and 34 patients with clinically non-functioning pituitary tumor (NFPA). Gonadotrophin and free alpha-subunit (SU) concentrations during daytime variations (samples were taken hourly for 24 h) and after stimulation with TRH were measured as well. Patients with NFPA had a higher prevalence of isolated secondary hypogonadism (20.6% vs 10.3%) and more severe pituitary failure (52.9% vs 6.9%) in comparison with acromegalic patients (p < 0.0001). However, there was no association between the tumor size and the anterior pituitary hypofunction (p = 0.1 and p = 0.9) in patients with NFPA and acromegaly respectively. In premenopausal women and in men with normal/low gonadotrophin levels, mean daytime levels of LH (0.75 +/- 0.6 vs 1.5 +/- 1.9 mlU/ml; p = 0.002) and FSH (2.1 +/- 2.7 vs 4.1 +/- 4.9 mlU/ml; p = 0.009) were higher in patients with acromegaly. There was no difference in the alpha-SU level (p = 0.9). Women with gonadotrophin levels compatible with menopause and men with elevated gonadotrophin levels had the same degree of gonadotrophin and alpha-SU elevation regardless of the tumor type. TRH induced significant rise of LH in 8 (23.5%), FSH in 5 (14.7%) and alpha-SU in 10 (29.4%) patients with NFPA. Among 29 patients with acromegaly LH rose in 6 (20.7%), FSH in 5 (17.2%) and alpha-SU in 3 (10.3%) patients. In conclusion, the anterior pituitary function is better preserved in patients with acromegaly than in patients with NFPA. It seems that the size of pituitary tumor is not the major factor in the pathogenesis of hypopituitarism in patients with macroadenomas. Gonadotrophin and possibly alpha-SU response to TRH exists not only in some patients with clinically non functioning pituitary tumors but also in some patients with acromegaly. Further investigations are need to explain if it represents a biochemical marker of a plurihormonal pituitary tumor in these patients.

Acromegaly↗
PubMed2001

Cognitive function and functional ability. A cross-sectional and longitudinal study at ages 85 and 95 in a non-demented population.

We studied the relationship between cognitive function and ability in daily life activities (ADL) at ages 85 (N=332) and 95 (N=63) cross-sectionally and longitudinally in representative populations of non-demented persons, in order to focus on manifestations related to healthy aging. Among the 85-year olds, 31% were independent, 42% were dependent on personal assistance in instrumental ADL (IADL) and 27% in personal ADL (PADL); the corresponding figures for the 95-year olds were 8, 40 and 52%, respectively. Regarding the relationship between cognitive function and ADL, the analysis could only be performed in the cross-sectional data. At age 85 a significant trend was found regarding nearly all cognitive tests for both men and women, indicating that subjects who were ADL-independent had better results than those dependent in IADL, and both IADL and PADL. At age 95, no such trend was found in males, but in females the trend was significant, and those dependent in ADL had poorer results in the separate cognitive tests. By combining the different cognitive tests into a compiled cognitive index, it was seen that the most ADL-dependent persons were more cognitively impaired both at ages 85 and 95, compared to persons who were ADL-independent. Not only cognitive functioning (OR 3.3), but also mobility (OR 4.9) and tiredness (OR 3.3) were independent predictors for ADL-dependence among the 85-year olds.

Activities of Daily Living↗
PubMed1997

[Functional voice quality assessment in curative microsurgery of laryngeal malignancies. Postoperative voice rehabilitation based on the "laryngeal double valve function"].

According to Negus and Pressman the sphincter systems of the vocal folds and the ventricular folds form a respiratory "laryngeal double valve function". Correspondingly, we found a physiological phonation system of the glottis and a pathological-compensatory one of the supraglottis. They appear to be regulated through an automatic phonatory control system with the glottal phonatory function evidently acting as sensor level. In order to confirm this hypothesis, objective voice analyses with glottal-relevant parameters of 26 voice-rehabilitated patients after minimally invasive laser surgery of glottal carcinomas are presented and integrated into a "hoarseness diagram" with the coordinates roughness and breathiness. Using statistically deliminated acoustic dusters, our data show a qualitative hierarchy of different postoperative phonation mechanisms. They demonstrate the influence of the vibratory capacity of glottal and supraglottal structures on the quality of the vibratory closure. Both functional parameters evidently determine the resulting voice quality in the sense of our hypothesis.

Female↗
PubMed1997

[Nerve transfer (neurotization) for functional reconstruction of arm functions in cervical root avulsions].

Neurotization procedures represent an important therapeutic option in patients with complete root avulsion due to traumatic brachial plexus injuries. A variety of normal donor nerves can be used, including intercostal nerves, accessory nerve, parts of the cervical plexus, phrenic nerve, and/or the contralateral C7 nerve root. The reconstructive neurotization procedure should be performed within 3-6 months following the trauma and, when successful, can lead to substantial improvement in motor function for the shoulder and upper arm and in sensory function for the forearm, hand and finger region. Neurotization can also be combined with neurolysis and/or transplantation to restore upper limb motor and sensory function in order to achieve greater therapeutic benefit for patients with posttraumatic brachial plexus lesions.

Arm↗
PubMed2004

Discrete functional contributions of cerebral cortical foci in voluntary swallowing: a functional magnetic resonance imaging (fMRI) "Go, No-Go" study.

Brain-imaging studies have shown that visually-cued, voluntary swallowing activates a distributed network of cortical regions including the precentral and postcentral gyri, anterior cingulate cortex (ACC), insula, frontoparietal operculum, cuneus and precuneus. To elucidate the functional contributions of these discrete activation foci for swallowing, a "Go, No-Go" functional magnetic resonance imaging (fMRI) paradigm was designed. Brain activation associated with visually-cued swallowing was compared with brain activation evoked by a comparable visual cue instructing the subject not to swallow. Region-of-interest analyses performed on data from eight healthy subjects showed a significantly greater number of activated voxels within the precentral gyrus, postcentral gyrus, and ACC during the "Go" condition compared to the "No-Go" condition. This finding suggests that the precentral gyrus, postcentral gyrus, and ACC contribute primarily to the act of swallowing. In contrast, the numbers of activated voxels within the cuneus and precuneus were not significantly different for the "Go" and "No-Go" conditions, suggesting that these regions mediate processing of the cue to swallow. Together these findings support the view that the discrete cortical foci previously implicated in swallowing mediate functionally distinct components of the swallowing act.

Adult↗
PubMed2001

Functional mapping of human medial frontal motor areas. The combined use of functional magnetic resonance imaging and cortical stimulation.

Two functional brain-mapping techniques, functional magnetic resonance imaging (fMRI) and cortical stimulation by chronically implanted subdural electrodes, were used in combination for presurgical evaluation of three patients with intractable, partial motor seizures. Brain mapping was focused on characterizing motor-related areas in the medial frontal cortex, where all patients had organic lesions. Behavioral tasks for fMRI involved simple finger and foot movements in all patients and mental calculations in one of them. These tasks allowed us to discriminate several medial frontal motor areas: the presupplementary motor areas (pre-SMA), the somatotopically organized SMA proper, and the foot representation of the primary motor cortex. All patients subsequently underwent cortical stimulation through subdural electrodes placed onto the medial hemispheric wall. In each patient, the cortical stimulation map was mostly consistent with that patient's brain map by fMRI. By integrating different lines of information, the combined fMRI and cortical stimulation map will contribute not only to safe and effective surgery but also to further understanding of human functional neuroanatomy.

Adult↗
PubMed2005

Myocardial viability assessment in patients with highly impaired left ventricular function: comparison of delayed enhancement, dobutamine stress MRI, end-diastolic wall thickness, and TI201-SPECT with functional recovery after revascularization.

This study compared different magnetic resonance imaging (MRI) methods with Tl(201) single photon emission computerized tomography (SPECT) and the "gold standard" for viability assessment, functional recovery after coronary artery bypass grafting (CABG). Twenty patients (64+/-7.3 years) with severely impaired left ventricular function (ejection fraction [EF] 28.6+/-8.7%) underwent MRI and SPECT before and 6 months after CABG. Wall-motion abnormalities were assessed by stress cine MRI using low-dose dobutamine. A segment with a nonreversible defect in Tl(201)-SPECT and a delayed enhancement (DE) in an area >50% of the entire segment, as well as an end-diastolic wall thickness <6 mm, was defined as nonviable. The mean postoperative EF (n=20) improved slightly from 28.6+/-8.7% to 32.2+/-12.4% (not significant). Using the Tl(201)-SPECT as the reference method, end-diastolic wall thickness, MRI-DE, and stress MRI showed high sensitivity of 94%, 93%, and 84%, respectively, but low specificities. Using the recovery of contractile function 6 months after CABG as the gold standard, MRI-DE showed an even higher sensitivity of 99%, end-diastolic wall thickness 96%, stress MRI 88%, and Tl(201)-SPECT 86%. MRI-DE showed advantages compared with the widely used Tl(201)-SPECT and all other MRI methods for predicting myocardial recovery after CABG.

Aged↗
PubMed2003

[Improvement of functional deficits, physical mobility and cognitive function by treatment in a geriatric day hospital].

OBJECTIVES AND METHODS: Several studies showed the efficacy of inpatient geriatric treatment. Different outcomes were reported for geriatric patients treated in outpatient facilities. To analyze the course of rehabilitation, 312 patients (62.2% female) with a mean age of 77.2 years (SD = 7.4) in a geriatric day hospital were evaluated regarding a) changes of functional deficits and mobility, b) cognitive function and c) depression. Patients were examined with a geriatric assessment including activities of daily living, Tinetti, Timed-up and go, Mini Mental State Examination (MMSE), Clock Completion Test, Handgrip Strength-Test, Money-Counting Test and Geriatric Depression Scale (GDS) at admission and discharge. RESULTS: All examined parameters had changed significantly after treatment. A clear decrease in the portion of patients with disability-related outcomes in the examined parameters (Barthel Index, Tinetti, Timed-up and go, MMSE, GDS) was demonstrated: a) the proportion of patients with a Barthel Index under 75 had decreased by 26.5%, the proportion of patients with an increased risk of falls was reduced by 27%, b) the proportion of patients with a MMSE Score less than 24 was decreased by 14.8% and c) mild effects were achieved in depression. CONCLUSIONS: Day hospital geriatric treatment leads to an improvement of functional deficits, mobility and mental health of patients. The results contrast to other studies in day hospital treatment.

Accidental Falls↗
PubMed2006

Relationship between insight, cognitive function, social function and symptomatology in schizophrenia: the West London first episode study.

OBJECTIVE: To examine the nature and clinical correlates of insight in first-episode schizophrenia, and how these differ from findings in established schizophrenia. METHOD: Insight (and insight dimensions), clinical symptoms, neurocognitive function and social function were assessed in 94 patients with first-episode schizophrenia or schizophreniform disorder according to DSM-IV criteria. RESULTS: Greater global insight was associated with more severe depression. Poor overall insight was associated significantly with more severe negative and disorganisation symptoms as well as poor working memory, and at a trend level with lower current IQ. Patients with poor insight perceived themselves to have a better level of independent performance at daily living activities. CONCLUSION: In first-episode psychosis, the clinical correlates of poor insight are similar to those reported for established schizophrenia. Those patients with greater insight may be at risk of depression. The complex relationships between insight, positive and negative symptoms, neurocognitive dysfunction and social function may reflect the multidimensional nature of insight.

Adolescent↗
PubMed2006

Effects of treatment with the atypical neuroleptic quetiapine on working memory function: a functional MRI follow-up investigation.

BACKGROUND: Working memory as a part of higher-order executive functions is defined by the parallel storage and processing of information. Recent functional fMRI studies have revealed a functional, interregional disintegration of a neuronal network connecting cortical, subcortical and cerebellar regions in schizophrenic patients (SZ). Cognitive impairment in working memory is a core psychopathological correlate of schizophrenic symptoms. Atypical neuroleptics such as quetiapine have shown good efficacy in treating positive and negative symptoms. The presented study evaluated the impact of a neuroleptic steady state treatment with quetiapine on the altered working memory activation patterns in schizophrenia. METHODS: Patients were examined by fMRI at baseline and after 12 weeks of steady state treatment with quetiapine. Matched healthy controls (HC) underwent baseline examination. In the scanner, stimuli were presented in a 2-back and 0-back condition of a working memory (wm) paradigm, whereby a degraded and a non-degraded version were used each time. Additionally, behavioural responses (reaction time to target stimuli and error ratio) were measured. RESULTS: At baseline, healthy controls revealed increased activity in the frontal lobe, especially in regions of the prefrontal cortex. Compared to HC, SZ showed hypoactivation in the right dorsolateral prefrontal cortex (DLPFC) and the ventrolateral prefrontal cortex (VLPFC) bilaterally for the 2-back condition. In the 2-back degraded condition there was a hypoactivation in both, the right DLPFC and the VLPFC. Additionally, patients showed bilaterally decreased activation in the basalganglia in the 2-back and in the right caudatus in the 2-back degraded condition compared to healthy controls. After treatment with quetiapine, patients activations patterns were increased. The pre-post comparison of the 2-back condition revealed a significant increase of activation in the left VLPFC at a significance level of 0.001 (uncorrected). The 2-back degraded condition led to a significant activation pattern in the lingual gyrus and the right precuneus. In both wm conditions, at baseline there were no differences in reaction time but only a worse performance in SZ. After treatment, behavioural measurement of responses, including reaction time and performance, showed slight improvements in SZ, although these did not reach statistical significance. CONCLUSIONS: The neuronal networks underlying working memory are clearly altered in schizophrenia. After 12 weeks of treatment with quetiapine monotherapy, patients showed significant clinical improvement and revealed increased BOLD activity in the VLPFC during a working memory task, although there was no improvement of cognitive performance.

Adult↗
PubMed2000

Motor function changes in the rat following severe spinal cord injury. Does treatment with moderate systemic hypothermia improve functional outcome?

Systemic hypothermia exerts neuroprotective effects following trauma and ischemia caused by vascular occlusion in the brain. In the spinal cord similar effects have been demonstrated following ischemia after aortic occlusion. We have previously presented protective effects on several morphological parameters in the early period after the injury, using an established spinal cord compression injury model and systemic hypothermia. In the present study we have evaluated the effects on motor function following severe spinal cord compression trauma and treatment with moderate systemic hypothermia. Thirty Sprague Dawley rats were randomized into three groups: In group 1 (n = 4), the animals underwent a hypothermic procedure, including a 2 h hypothermic period with a body temperature of 30 degrees C, following the initial laminectomy. In group 2 (n = 12) a 50 g compression was applied to the spinal cords for 5 min, after which the animals were kept under normothermic anesthesia for 3 h. In group 3 (n = 14), the animals underwent the same trauma procedure as in group 2 and the same hypothermic procedure as in group 1. The animals were allowed to survive for 14 days, during which the motor function was recorded. This degree of trauma results in a non-reversible paraplegia, and the addition of systemic hypothermia as described above did not alter the neurological recovery as measured by two different methods of recording the motor function up to two weeks after injury. All animals survived in group 1. However, the mortality rates in group 2 were 25% and in group 3, 50%, respectively, which mirrors the severity of the trauma. The application of systemic hypothermia and the lack of experimental therapeutic success highlight the difficulties of transferring experimental beneficial neuroprotective effects to a clinically useful treatment method. In this experimental set-up the effects of the severe primary injury may overshadow the effects of the secondary injury mechanisms, which limits the therapeutic possibilities of systemic hypothermic treatment.

Animals↗