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Results for “functionality”

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At least 685 records · Page 38Linked to original sources

PubMed2000

[Relationship between exercise capacity and left ventricular function at rest in patients with heart insufficiency: radionuclide continuous monitoring of left ventricular function].

PURPOSE: To evaluate the relationship of systolic and diastolic function at rest to exercise capacity. MATERIAL AND METHODS: Seventeen patients with ischemic heart failure were included in the study. Ambulatory left ventricular monitoring at rest and during upright exercise with combined analysis of pulmonary gas exchange was performed. Ejection fraction, end-diastolic volume, end-systolic volume, stroke volume, cardiac output, and peak filling rate were measured. RESULTS: Significant positive correlations were found between rest ejection fraction and peak oxygen consumption (r = .60, p < .01), peak cardiac output (r = .77, p < .0001), peak stroke volume (r = .67, p < .005), and peak ejection fraction (r = .69, p < .005). On the other hand, peak filling rate at rest showed a significant inverse correlation with peak end-diastolic (r = -.48, p < .05) and end-systolic (r = -.66, p < .005) volumes. The patients were then subgrouped into two groups according to their rest ejection fraction (lower or higher than 40%). In the group with ejection fraction less than 40% a significant correlation was observed between rest ejection fraction and both peak stroke volume (r = .66, p < .05) and peak ejection fraction (r = .69, p < .05). In the same group of patients an inverse correlation was found between peak filling rate and both end-diastolic (r = -0.65, p < .05) and end-systolic (r = -.82, p < .005) volumes. CONCLUSIONS: The results of the present study suggest that exercise capacity is related to left ventricular function at rest and that rest diastolic function might be a determinant of left ventricular function during exercise in patients with heart failure.

Exercise Tolerance↗

PubMed2002

Functional electrical stimulation in tetraplegic patients to restore hand function.

The purpose of this collective review is to describe a new form of functional electrical stimulation called neuroprosthesis. This unique technology has been devised to produce lateral pinch and palmar grasp in persons with C5 and C6 motor level spinal cord injuries. This neuroprosthesis includes external as well as implanted components. First, a receiver is surgically implanted into the patient's chest above a pectoralis major muscle. The receiver stimulator is then connected to 8 surgically implanted epimysial or intramuscular electrodes. Restoration of upper extremity function can greatly improve the lives of people affected with tetraplegia. When contralateral shoulder movements trigger an external transmitting coil, it sends a radio wave impulse to the stimulator inducing contraction of the muscles. Many tetraplegics are regaining hand function using implanted functional electrical stimulation. One major limitation is that the key muscles to be stimulated may have lower motor neuron damage, but this obstacle has been successfully overcome using surgical modifications of the biomechanics of the hand.

Activities of Daily Living↗

PubMed1987

Regional time-based functional imaging of hepatocyte function.

Hepatocyte function was analyzed following the injection of 5 mCi of Tc-99m disofenin by the computer generation of three kinds of functional images designed to portray regional rates of hepatic uptake. Nineteen patients were analyzed, of whom eight had no overt liver disease, five had active hepatitis, five had cirrhosis, and one had acute cholecystitis. Functional images were graded according to lack of regional homogeneity of accumulation. Uptake kinetics were found to be significantly more homogeneous in normal subjects, becoming increasingly heterogeneous in hepatitis and cirrhosis patients, respectively. Thus functional imaging may provide a tool for the quantitative analysis of parenchymal disruption in liver disease.

Adult↗

PubMedDate not supplied

[Respiratory function in extrinsic allergic alveolitis caused by pigeons. Clinical, pathological and functional correlation].

Lung function tests (LFT) were performed in 71 patients with proven extrinsic allergic alveolitis due to pigeons (EAA-P), and they were correlated with lung biopsy (LB) findings. Lung function studies were analyzed to evaluate the clinical course of these patients treated with corticosteroids. Restrictive pulmonary function impairment was found in all cases (vital capacity 38 +/- 4%), residual volume was increased in 9 out of 14 patients (64%) (RV = 0.51 +/- 0.06 L.) and bronchial obstruction was a feature in 11/14 patients (78%) (MMEF = 53 +/- 4%). In all cases a low Pa02 was observed (44 +/- 2 mmHg) and in six an increase in PaC02 was detected. The vital capacity did not correlate with the degree of inflammation or fibrosis observed by LB. A significant negative correlation was found between Pa02 and the degree of inflammation (r = 0.68, p X 0.05) as well as with fibrosis + inflammation degrees (r = -0.63, p less than 0.05). In general, initial LFT and clinical improvement occur simultaneously. Lung function tests support the diagnosis of EAA-P, but are not capable of separating inflammation from lung fibrosis.

Adolescent↗

PubMed1994

[Deterioration of liver function following endoscopic injection sclerotherapy of esophageal varices--significance of the new liver function test "intravariceal injection (I.I.) index"].

Changes of liver functions associated with endoscopic injection sclerotherapy (EIS) were investigated in 143 patients with remarkable esophageal varices. The index used for evaluating hepatic reserve was the ratio between the increase of total bilirubin and the increase of LDH after EIS [I.I. index = (delta T.Bil./delta LDH) x 100] in cases treated by intravariceal injection of 5% ethanolamine oleate. I.I. index value caused by hemolysis was stable and always below 0.2, while the elevation of I.I. index above 0.2 was regarded as the reflection of the deterioration of liver function. After the entire sessions of EIS, the changes of liver function tests before and after EIS were estimated in 104 cases using 3 factors as follows; (1) delta T.Bil.; increase of total bilirubin more than 0.5 mg/dl (2) delta PT; decrease of prothrombin time more than 5% (3) delta ICG R15; increase of ICG R15 more than 5%. I.I. index of group I (without any changes of 3 factors mentioned above; n = 66) was 0.22 +/- 0.16, approximately within normal range. However, in group II (with 1 factor; n = 29), group III (with 2 factors; n = 5), group IV (with all factors; n = 4), I.I. index was elevated according to the severity of their liver dysfunction. The cases whose I.I. index value increased gradually during the course of EIS, were apt to deteriorate the liver functions and therefore, should be carefully observed. Also, I.I. index seems to reflect the prognosis of the patients treated by EIS for some extent, since the survival period of the cases treated by EIS were correlative with the value of I.I. index (r = -0.542, p < 0.01), and I.I. index of 32 cases who survived for longer than 5 years after EIS was almost normal (0.22 +/- 0.15).

Adult↗

PubMed2006

Possible relations between thyroid function, endothelium, and kidney and liver function in kidney allograft recipients.

BACKGROUND: Renal function affects the thyroid gland in many ways. Disturbances in hemostasis and endothelial damage are common complications of kidney disease. Endothelial dysfunction may link these two processes. AIM AND METHODS: This cross-sectional study examined thyroid hormones in relation to markers of endothelial damage and inflammation among 80 kidney allograft recipients and 29 healthy volunteers. Thyroid hormones, markers of endothelial damage (vWF, thrombomodulin, intracellular adhesion molecule [ICAM] vascular adhesion molecule [VCAM], CD146), markers of inflammation (hsCRP), other hemostatic parameters (thrombin-antithrombin complexes [TAT], prothrombin fragments 1 + 2 [F1 + 2], plasmin-antiplasmin complexes, tissue plasminogen activator and its inhibitor, platelet glycoprotein [V-GPV]) as well as P-selectin were measured using commercially available kits. RESULTS: Total T3 was significantly lower among kidney allograft recipients, whereas markers of endothelial dysfunction and inflammation were significantly elevated over controls. In kidney allograft recipients total T3 was independently related to PAI-1, ICAM, and eGFR, whereas free T3 was independently related to thrombomodulin, aspartate, and alanine aminotransferases, hemoglobin, urea, eGFR, dose of cyclosporine and treatment with mycophenolate mofetil/azathioprine. Total T4 was related to aspartate and alanine aminotransferases, dose of cyclosporine, PAI-1, and ICAM. In multiple regression analysis the only correlates of T3 were PAI-1 and ICAM, whereas the only correlates of free T3 were thrombomodulin, aspartate aminotransferase, eGFR, and cyclosporine dose. In healthy volunteers GPV was related only to TSH. CONCLUSIONS: We described novel relations between thyroid hormones and markers of endothelial dysfunction in kidney transplant recipients. In kidney transplant recipients thyroid function metrics were associated with endothelial damage, immunosuppressive treatment, liver and kidney function. Therefore, the relations between thyroid axis and endothelium in kidney allograft recipients merit additional studies.

Adult↗

PubMed2004

Evaluation of sexual function with an international index of erectile function in subjects taking finasteride for androgenetic alopecia.

OBJECTIVE: To evaluate variations in sexual and erectile function in subjects taking 1 mg of finasteride for androgenetic alopecia by administering the abridged 5-item version of the International Index of Erectile Function (IIEF-5) questionnaire before and during treatment. DESIGN: In a multicenter study, 186 patients with androgenetic alopecia were asked to complete the IIEF-5 regarding the domain of erectile function before (at baseline) and 4 to 6 months after beginning finasteride treatment. The test was self-administered. SETTING: The study was conducted in 7 institutional dermatology departments in Italy (Bologna, Rome, Genoa, Cagliari, Milan, Florence, and Bari). PATIENTS: A total of 186 patients with androgenetic alopecia were evaluated before and 4 to 6 months after the initiation of finasteride therapy (1 mg). All patients (age range, 19-43 years; mean age, 28.3 years) were followed up as outpatients. RESULTS: The score on each of the 5 domains of the IIEF-5 did not show any significant change after 4 to 6 months of treatment. CONCLUSIONS: Our results support the clinical impression that sexual side effects are actually much less common than reported in clinical trials. The sexual function of all patients remained stable during treatment with 1 mg of finasteride.

5-alpha Reductase Inhibitors↗

PubMed1977

Kinetics of hepatocellular proliferation as a function of the microvascular structure and functional state of the liver.

An analysis of hepatocellular proliferation in regenerating rat liver reveals a dependence of kinetic parameters on the microvascular structure of the liver. Influx kinetics of hepatocytes into DNA synthesis as well as cell cycle phases vary in different parts of the liver lobule between the afferent and efferent vascular poles. Heterogeneity of the proliferative response and size limitations on cell cycle compartments appear to be intimately related to the actual functional state of the individual liver cell. Modifications of liver cell functions result in variations of the proliferative activity. Phenobarbital-induced hypertrophy of hepatocytes reveals a permissive action on G1- S influx. Selective destruction of the subpopulations, by allyl formate, leads to a new functional determination of the residual liver and to a change in proliferative compartments. Maximum modulation of cell cycle compartments is obtained by hydroxyurea-induced synchronization of hepatocytes after partial liver resection. During hydroxyurea treatment, the regenerating liver shows a pronounced cellular hypertrophy. After release from hydroxyurea block, cells embark on DNA synthesis simultaneously. The DNA synthesizing compartment comprises almost the entire liver cell population. Heptotrophic factors might play a part in regulating or modifying hepatocellular function and proliferative response after cell loss.

Allyl Compounds↗

PubMed2006

Toward the rational design of functionalized pentacenes: reduction of the impact of functionalization on the reorganization energy.

For the widely studied high-carrier-mobility species, pentacene, it is found that perfluorination turned it into an n-type organic field-effect transistor (OFET), but doubled the internal reorganization energy (lambda) of the electron/hole hopping. Here, Cl- and N-functionalized pentacenes are designed to test two strategies that may reduce the impact of functionalization on lambda. Calculation results show that the strategies are feasible. Moreover, combined with crystal-structure data of Cl- and N-functionalized aromatic compounds, it is concluded that compared to fluorination, the presence of Cl and N atoms in pentacene not only reduces the influence of functionalization on lambda and affords a larger window for tuning HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies, but also provides the opportunity to promote pi-stacked structures through ClCl and C--HN interactions.

Journal Article↗

PubMed1989

Longitudinal study of leukocyte functions in homosexual men seroconverted for HIV: rapid and persistent loss of B cell function after HIV infection.

The early effects of infection with human immunodeficiency virus (HIV) were investigated in homosexual men who had seroconverted for anti-HIV antibodies. Leukocyte functional activities were determined in longitudinally collected peripheral blood mononuclear cell samples. During the first 10 months following seroconversion, anti-CD3 monoclonal antibody-induced T cell proliferation, monocyte accessory function and T helper activity on B cell differentiation in a pokeweed mitogen-driven system were not affected. In contrast, from the moment of seroconversion on, B cells of seroconverted men failed to produce immunoglobulin in the pokeweed mitogen-driven system. This defect was not restored by addition of normal CD4+ T cells. Immunoglobulin synthesis induced by Staphylococcus aureus and interleukin 2 decreased gradually, until it was completely lost 10 months after seroconversion. In addition, proliferation in response to anti-IgM or Staphylococcus aureus by B cells from HIV seroconverted men was decreased. The lack of inducible in vitro B cell activity was not accompanied by elevated spontaneous Ig synthesis by B cells of the seroconverted men. In the second group of men studied during the 2nd year following seroconversion, T helper activity on normal B cell differentiation significantly decreased, whereas anti-CD3-induced T cell proliferation and monocyte accessory function were not significantly affected. Our results demonstrate that in almost all HIV-infected individuals B cell functional defects are the first leukocyte abnormalities observed preceding defects in T helper activity.

Antibody Formation↗

PubMed1988

Nuclear factor NF-kappa B can interact functionally with its cognate binding site to provide lymphoid-specific promoter function.

Enhancers and promoters, cis-acting regulators of mammalian gene expression, are modular units containing multiple short binding sites for specific trans-acting transcription factors. To investigate if factors binding to enhancer sequences are functionally different from promoter-binding factors, we asked if a short DNA sequence element in the immunoglobulin kappa (kappa) light chain enhancer that binds to the nuclear factor NF-kappa B could also serve as a functional promoter element. A synthetic oligonucleotide containing this binding site was placed in either orientation upstream of the beta-globin TATA-element. In myeloma cells, the NF-kappa B binding site efficiently directed transcription. The promoter activity was directly correlated with the presence of the nuclear factor NF-kappa B: there was no transcription in fibroblasts or in unstimulated pre-B cells where the factor was absent. Transcription could be stimulated in pre-B cells by treatments known to activate NF-kappa B. Thus, the same nuclear factor can act as a positive activator of both enhancer and promoter function, suggesting that the two functions involve similar events in the transcription process.

Animals↗

PubMed2003

Performance of time-dependent density functional and Green functions methods for calculations of excitation energies in radicals and for Rydberg electronic states.

Time-dependent density functional (TD-DFT) and perturbation theory-based outer valence Green functions (OVGF) methods have been tested for calculations of excitation energies for a set of radicals, molecules, and model clusters simulating points defects in silica. The results show that the TD-DFT approach may give unreliable results not only for diffuse Rydberg states, but also for electronic states involving transitions between MOs localized in two remote from each other spatial regions, for example, for charge-transfer excitations. For the. O-SiX(3) clusters, where X is a single-valence group, TD-DFT predicts reasonable excitation energies but incorrect sequence of electronic transitions. For a number of cases where TD-DFT is shown to be unreliable, the OVGF approach can provide better estimates of excitation energies, but this method also is not expected to perform universally well. The OVGF performance is demonstrated to be satisfactory for excitations with predominantly single-determinant wave functions where the deviations of the calculated energies from experiment should not exceed 0.1-0.3 eV. However, for more complicated transitions involving multiple bonds or for excited states with multireference wave functions the OVGF approach is less reliable and error in the computed energies can reach 0.5-1 eV.

Journal Article↗

PubMed2004

Performance of the Harris functional for extended basis sets at the Hartree-Fock and density functional levels.

The Harris functional is a noniterative variational procedure that uses an input charge density to produce an energy that is surprisingly accurate compared to the converged Kohn-Sham self-consistent result. We adapted and generalized this functional for the Hartree-Fock closed- and open-shell cases as well as examined its use for hybrid density functional methods such as B3LYP. Analysis of extended basis set calculations shows that at the B3LYP level an input density formed from a double zeta + polarization orbital basis is accurate enough to reproduce the energy of triple zeta + double polarization + diffuse orbital basis. For large molecules this translates into a computational speed that can be an order of magnitude faster. In the case of Hartree-Fock calculations a "bootstrapping technique" that employs successive applications of the Harris functional can further reduce computational times while retaining sufficient accuracy.

Journal Article↗

PubMed2006

An iterative knowledge-based scoring function to predict protein-ligand interactions: II. Validation of the scoring function.

We have developed an iterative knowledge-based scoring function (ITScore) to describe protein-ligand interactions. Here, we assess ITScore through extensive tests on native structure identification, binding affinity prediction, and virtual database screening. Specifically, ITScore was first applied to a test set of 100 protein-ligand complexes constructed by Wang et al. (J Med Chem 2003, 46, 2287), and compared with 14 other scoring functions. The results show that ITScore yielded a high success rate of 82% on identifying native-like binding modes under the criterion of rmsd < or = 2 A for each top-ranked ligand conformation. The success rate increased to 98% if the top five conformations were considered for each ligand. In the case of binding affinity prediction, ITScore also obtained a good correlation for this test set (R = 0.65). Next, ITScore was used to predict binding affinities of a second diverse test set of 77 protein-ligand complexes prepared by Muegge and Martin (J Med Chem 1999, 42, 791), and compared with four other widely used knowledge-based scoring functions. ITScore yielded a high correlation of R2 = 0.65 (or R = 0.81) in the affinity prediction. Finally, enrichment tests were performed with ITScore against four target proteins using the compound databases constructed by Jacobsson et al. (J Med Chem 2003, 46, 5781). The results were compared with those of eight other scoring functions. ITScore yielded high enrichments in all four database screening tests. ITScore can be easily combined with the existing docking programs for the use of structure-based drug design.

Acetylcholinesterase↗

PubMed1994

Technical considerations in two-stage functioning free muscle transplantation reconstruction of both flexor and extensor functions of the forearm.

We report on two patients with severe injuries of the forearm who were reconstructed using functioning free muscle transplantation (FFMT) for individual replacement of flexor and extensor function. In both cases a two-stage procedure was performed: The extensor reconstruction preceded the flexor reconstruction by 4-6 months. The extensor digitorum communis and flexor digitorum profundus were successfully reconstructed in both cases using bilateral gracilis FFMT. In one case the flexor pollicis longus and extensor pollicis longus were also reconstructed using the adductor longus in addition to the gracilis. Clinical follow-up was a minimum of 2 years. Both patients achieved wrist control, excellent finger flexion, and metacarpophalangeal joint extension. One patient also had good interphalangeal finger extension, but the other developed a persistent claw deformity due to the lack of recovery of ulnar nerve function. Performing the extensor reconstruction prior to the flexor reconstruction theoretically allows a more rapid return of function and a shorter rehabilitation period than using the converse sequence.

Adult↗

PubMed1997

The functional scout image: immediate mapping of cortical function at 4 Tesla using receiver phase cycling.

A rapid method of generating functional scout images to map cortical activity is presented. Maps were produced immediately "on-line" on the scanner's console using fast low-angle shot gradient-recalled echo and echo-planar imaging sequences without special hardware. To demonstrate the technique, raw data collected during photic stimulation and dark control periods were subtracted through phase alternation of the receiver with constant transmitted radio frequency phase. A blood oxygen level-dependent signal difference map was produced by magnitude reconstruction of the resulting complex-difference data. Maps improved in contrast with an increasing number of stimulation-control cycles and showed similar areas of activation to traditional fMRI processing methods. Such a functional scout procedure allows rapid localization of brain function within the anatomical region of interest. From these functional scout images, slices or voxels may be planned by using the scanner manufacturers prescription tools for further specialized studies.

Brain Mapping↗

PubMed1996

Mapping the functional surface of insulin by design: structure and function of a novel A-chain analogue.

Functional surfaces of a protein are often mapped by combination of X-ray crystallography and mutagenesis. Such studies of insulin have yielded paradoxical results, suggesting that the native state is inactive and reorganizes on receptor binding. Of particular interest is the N-terminal alpha-helix of the A-chain. Does this segment function as an alpha-helix or reorganize as recently proposed in a prohormone-convertase complex? To correlate structure and function, we describe a mapping strategy based on protein design. The solution structure of an engineered monomer ([AspB10, LysB28, ProB29]-human insulin) is determined at neutral pH as a template for synthesis of a novel A-chain analogue. Designed by analogy to a protein-folding intermediate, the analogue lacks the A6-A11 disulphide bridge; the cysteine residues are replaced by serine. Its solution structure is remarkable for segmental unfolding of the N-terminal A-chain alpha-helix (A1 to A8) in an otherwise native subdomain. The structure demonstrates that the overall orientation of the A and B chains is consistent with reorganization of the A-chain's N-terminal segment. Nevertheless, the analogue's low biological activity suggests that this segment, a site of clinical mutation causing diabetes mellitus, functions as a preformed recognition alpha-helix.

Amino Acid Sequence↗

PubMed2003

An algorithm for rapid calculation of a probabilistic functional atlas of subcortical structures from electrophysiological data collected during functional neurosurgery procedures.

The paper introduces an optimal algorithm for rapid calculation of a probabilistic functional atlas (PFA) of subcortical structures from data collected during functional neurosurgery procedures. The PFA is calculated based on combined intraoperative electrophysiology, pre- and intraoperative neuroimaging, and postoperative neurological verification. The algorithm converts the coordinates of the neurologically most effective contacts into probabilistic functional maps taking into account the geometry of a stimulating electrode. The PFA calculation comprises the reconstruction of the contact coordinates from two orthogonal projections, normalizing (warping) the contacts modeled as cylinders, voxelizing the contact models, calculating the atlas, and computing probability. In addition, an analytical representation of the PFA is formulated based on Gaussian modeling. The initial PFA has been calculated from the data collected during the treatment of 274 Parkinson's disease patients, most of them operated bilaterally (487 operated hemispheres). It contains the most popular stereotactic targets, the subthalamic nucleus, globus pallidus internus, and ventral intermedius nucleus. The key application of the algorithm is targeting in stereotactic and functional neurosurgery, and it also can be employed in human and animal brain research.

Algorithms↗