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PubMed1992

Catecholamine synthesizing enzymes in 70 cases of functioning and non-functioning phaeochromocytoma and extra-adrenal paraganglioma.

Immunohistochemical localization of the catecholamine synthesizing enzymes, tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT), was investigated in 70 cases of functioning and non-functioning phaeochromocytomas comprising 52 of adrenal and 18 of extra-adrenal origin. Of 59 functioning tumours, 30 were mixed epinephrine and norepinephrine-producing (mixed type) and 29 were norepinephrine-producing tumours. TH, AADC and DBH were detected in all functioning phaeochromocytomas, but PNMT was limited to the mixed-type phaeochromocytomas. Non-functioning phaeochromocytomas were divided into two groups, comprising a complete type, which induced neither elevated plasma catecholamines nor their metabolites in urine, and an incomplete type which exhibited no elevated plasma catecholamines, but showed a slightly high urinary vanillylmandelic acid level. In the non-functioning complete-type tumours, immunoreactive TH was negative, but the incomplete tumours of the adrenal medulla had all four enzymes, and corresponded to a mixed-type phaeochromocytoma. AADC and DBH were present universally in all functioning and non-functioning tumours, including TH-negative tumours. TH is a rate-limiting enzyme of catecholamine biosynthesis and deficiency of TH is an important feature of extra-adrenal non-functioning phaeochromocytomas.

Adrenal Gland Neoplasms↗

PubMed1986

Polite DNA: functional density and functional compatibility in genomes.

Certain as yet poorly defined functions of DNA appear to involve collectively domain-sized sequences. It is proposed that most sequence segments within a domain may be either functionally superfluous or instrumental, depending on how many related sequences are present in the domain. When redundant and functionally dispensable, such DNA segments presumably still have to conform to compositional or sequence-motif patterns that characterize the domain. In its relations with neighboring sequences, such DNA is required to be "polite." Polite DNA is DNA that, without being crucially involved in function, is subject to constraints of conformity and, through its base composition, respects a function for which it is not required. This concept is developed by contrasting the distribution of specific and general functions over DNA with this distribution as found in proteins and by distinguishing functional compatibility from pivotal functionality. The sequence constraints to which heterochromatin as well as, apparently, long interspersed repetitive sequences are known to be subject seem to imply that DNA, even when it does not carry out a pivotal function, is indeed, at the very least, required to be polite.

Animals↗

PubMed2001

[New insights into brain function by combination of transcranial magnetic stimulation and functional brain mapping].

The present paper aims to summarize potential applications of transcranial magnetic stimulation (TMS) combined with functional brain imaging. Transcranial magnetic stimulation is a well-established noninvasive tool for stimulating circumscribed areas of the human cortex. Functional imaging techniques such as positron emission tomography, functional magnetic resonance imaging, and electroencephalographic mapping enable assessment of TMS-related functional brain activation. A combination of TMS and functional imaging can be useful in three principal ways. (1) Brain imaging before TMS is helpful in defining the accurate coil position over a distinct cortical area which is targeted by TMS. Since TMS can be used to interfere with regional cortical function during a given task, the effects of focal TMS on task performance can help to clarify the task-specific functional contribution of a given cortical area which has previously shown task-related activation in a functional imaging study. (2) Imaging the brain during TMS is a promising approach for assessing cortical excitability and intracerebral functional connectivity. (3) By evaluating lasting effects of TMS, brain imaging after TMS can be employed to study the plasticity of the human cortex. Moreover, this approach will help to advance our understanding of therapeutical effects related to TMS.

Brain↗

PubMed2006

Rapid detection of differential item functioning in assessments of health-related quality of life: The Functional Assessment of Cancer Therapy.

REASON FOR STUDY: Differential item functioning (DIF) occurs when a test item functions differently in different groups when controlling for the level of the underlying construct measured by the test. DIF assessment is a first step in the evaluation of test bias. We sought to demonstrate a rapid hybrid approach to DIF detection by determining the presence and scale-level impact of DIF related to eight covariates in four domains measured by the Functional Assessment of Cancer Therapy (FACT). MAJOR FINDINGS: The number of items found with DIF in each domain depended on the criterion chosen to define the presence of DIF. With a few exceptions, scale-level differential functioning was similar regardless of the criteria chosen. For physical well-being, there was relevant scale-level differential functioning related only to race. For social and family well-being, there was relevant scale-level differential functioning related to each of the covariates. For emotional well-being, there was relevant scale-level differential functioning related to ethnicity, language, and race. For functional well-being, there was relevant scale-level differential functioning related to ethnicity, race, education, and self- vs. interviewer-administration. PRINCIPAL CONCLUSIONS: Our rapid hybrid approach to DIF detection may be broadly applicable in other studies of health-related quality of life.

Adolescent↗

PubMed1995

The role of three dimensional functional lung imaging in radiation treatment planning: the functional dose-volume histogram.

PURPOSE: During thoracic irradiation (XRT), treatment fields are usually designed to minimize the volume of nontumor-containing lung included. Generally, functional heterogeneities within the lung are not considered. The three dimensional (3D) functional information provided by single photon emission computed tomography (SPECT) lung perfusion scans might be useful in designing beams that minimize incidental irradiation of functioning lung tissue. We herein review the pretreatment SPECT scans in 86 patients (56 with lung cancer) to determine which are likely to benefit from this technology. METHODS AND MATERIALS: Prior to thoracic XRT, SPECT lung perfusion scans were obtained following the intravenous injection of approximately 4 mCi of 99mcTc-labeled macro-aggregated albumin. The presence of areas of decreased perfusion, their location relative to the tumor, and the potential clinical usefulness of their recognition, were scored. Patients were grouped and compared (two-tailed chi-square) based on clinical factors. Conventional dose-volume histograms (DVHs) (DVFHs) are calculated based on the dose distribution throughout the computed tomography (CT)-defined lung and SPECT-defined perfused lung, respectively. RESULTS: Among 56 lung cancer patients, decreases in perfusion were observed at the tumor, adjacent to the tumor, and separate from the tumor in 94%, 74%, and 42% of patients, respectively. Perfusion defects adjacent to the tumor were often large with centrally placed tumors. Hypoperfusion in regions separate from the tumor were statistically most common in patients with relatively poor pulmonary function and chronic obstructive pulmonary disease (COPD). Considering all SPECT defects adjacent to and separate from the tumor, corresponding CT abnormalities were seen in only approximately 50% and 20% of patients, respectively, and were generally not as impressive. Following XRT, hypoperfusion at and separate from the tumor persisted, while defects adjacent to the tumor improved in several patients. In four patients who achieved a complete response scored by CT with chemotherapy prior to XRT, persistent hypoperfusion was present at and adjacent to the tumor site in three. Among 30 patients with cancers not arising in the lung (14 breast, 12 lymphoma, 4 others), perfusion defects were seen in only 4 (2 adjacent and 2 apart). Recognition of decreases in perfusion mainly impacted on treatment planning for a few patients with poor pulmonary function and limited target volumes. DVFHs have been useful in beam selection for patients with marked perfusion heterogeneities. CONCLUSIONS: Lung perfusion scans provide functional information not provided by CT scans that can be useful in designing radiation treatment beams that minimize incidental irradiation of the function regions of the lung. This approach appears to be most helpful in patients with gross intrathoracic lung cancer, especially those with small targets and relatively poor pulmonary function. One limitation of this approach is that some of the defects adjacent to the tumor site reperfuse following treatment, indicating that these scans identify perfusion rather than potential perfusion. Three dimensional functional data can be used to generate DVFHs that may be more predictive of the physiological consequences of the radiation than conventional DVHs. Additional work is currently underway to test this hypothesis.

Forced Expiratory Volume↗

PubMed2006

Osteoblast functions on functionalized PMMA-based polymers exhibiting Staphylococcus aureus adhesion inhibition.

Staphylococcus aureus adhesion and osteoblast functions were assessed on functionalized poly(methyl methacrylate)-based terpolymers bearing randomly distributed carboxylate and sulfonate groups. These terpolymers were synthesized by radical polymerization, characterized by nuclear resonance spectroscopy and classified by the ratio R=[COO(-)/COO(-)+SO(3)(-)] in the range 0.5-0.8. Bacterial adhesion study showed that fibronectin-coated terpolymers with R varying from 0.5 to 0.8 exhibited inhibition rate of S. aureus adhesion from 90% to 98% as compared to the adhesion on unfunctionalized poly(methyl methacrylate). In contrast, the adhesion of osteoblasts onto the same functionalized terpolymers was decreased by 20% when compared to the results obtained on poly(methyl methacrylate). While the amount of attached osteoblasts are similar onto all the functionalized terpolymers whatever its R value, the cell proliferation was different and was found to vary with R in the range 0.5-0.8. Osteoblast proliferation, alkaline phosphatase activity and accumulation of calcium in the extracellular matrix of these cells, cultured on the functionalized terpolymers with R equal to 0.7-0.8 were similar to that observed onto non-functionalized poly(methyl methacrylate). In contrast, osteoblast proliferation was inhibited on terpolymers with an R value around 0.6. These results provide evidence that functionalized poly(methyl methacrylate)-based terpolymers with R ratio equaling 0.7-0.8 simultaneously inhibit bacteria adhesion and support osteoblast functions pertinent to new bone formation. These functionalized polymers could, therefore, be used as coating or grafted on orthopedic and dental implants to render them both bone compatible and able to prevent bacterial infection.

Animals↗

PubMed2005

Distinctions between manipulation and function knowledge of objects: evidence from functional magnetic resonance imaging.

A prominent account of conceptual knowledge proposes that information is distributed over visual, tactile, auditory, motor and verbal-declarative attribute domains to the degree to which these features were activated when the knowledge was acquired [D.A. Allport, Distributed memory, modular subsystems and dysphagia, In: S.K. Newman, R. Epstein (Eds.), Current perspectives in dysphagia, Churchill Livingstone, Edinburgh, 1985, pp. 32-60]. A corollary is that when drawing upon this knowledge (e.g., to answer questions), particular aspects of this distributed information is re-activated as a function of the requirements of the task at hand [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects. Brain and Language, 82 (2002) 179-199; L.J. Buxbaum, T. Veramonti, M.F. Schwartz, Function and manipulation tool knowledge in apraxia: knowing 'what for' but not 'how', Neurocase, 6 (2000) 83-97; W. Simmons, L. Barsalou, The similarity-in-topography principle: Reconciling theories of conceptual deficits, Cognitive Neuropsychology, 20 (2003) 451-486]. This account predicts that answering questions about object manipulation should activate brain regions previously identified as components of the distributed sensory-motor system involved in object use, whereas answering questions about object function (that is, the purpose that it serves) should activate regions identified as components of the systems supporting verbal-declarative features. These predictions were tested in a functional magnetic resonance imaging (fMRI) study in which 15 participants viewed picture or word pairs denoting manipulable objects and determined whether the objects are manipulated similarly (M condition) or serve the same function (F condition). Significantly greater and more extensive activations in the left inferior parietal lobe bordering the intraparietal sulcus were seen in the M condition with pictures and, to a lesser degree, words. These findings are consistent with the known role of this region in skilled object use [K.M. Heilman, L.J. Gonzalez Rothi, Apraxia, In: K.M. Heilman, E. Valenstein (Eds.), Clinical Neuropsychology, Oxford University Press, New York, 1993, pp. 141-150] as well as previous fMRI results [M. Kellenbach, M. Brett, K. Patterson, Actions speak louder than functions: the importance of manipulability and action in tool representation, Journal of Cognitive Neuroscience, 15 (2003) 30-46] and behavioral findings in brain-lesion patients [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects, Brain and Language, 82 (2002) 179-199]. No brain regions were significantly more activated in the F than M condition. These data suggest that brain regions specialized for sensory-motor function are a critical component of distributed representations of manipulable objects.

Adult↗

PubMed2006

Motor assessment of upper extremity function and its relation with fatigue, cognitive function and quality of life in multiple sclerosis patients.

OBJECTIVES: The aim of this study was to assess the motor function of upper extremity and its relation with fatigue, cognitive function and quality of life in Multiple Sclerosis (MS) patients. DESIGN: Cross-sectional and controlled study. SETTING: Outpatient clinic in a university hospital. SUBJECTS: Thirty-one patients with MS (25 women, 6 men; mean age 39.74 +/- 10.10 years; mean EDSS, 2.56 +/- 1.91) and 30 healthy subjects (20 women, 10 men; mean age 33.56 +/- 8.85 years) were enrolled into the study. MAIN MEASURES: Nine-hole peg test (9-HPT) and Valpar Component Work Sample Test (VCWS-4), Upper Extremity Index (UEI), Paced Auditory Serial Addition Test (PASAT), Fatigue Severity Scale (FSS), and the Multiple Sclerosis Quality of Life-54 (MSQOL-54). RESULTS: MS patients showed significant impairment in upper extremity motor functions, cognitive function and excessive fatigue compared to controls (p < 0.05). 9-HPT in MS group correlated with EDSS, UEI and MSQOL-54 physical health and cognitive function, whereas VCWS-4 scores (assembly right, assembly left and disassembly) correlated only with EDSS and UEI. No correlation was found between the VCWS-4 and cognitive function and fatigue in both of the groups. Compared to control group, a strong correlation existed between the 9-HPT and VCWS-4 in MS patients (p < 0.05). CONCLUSION: The results indicate that disability level (EDSS), UEI and cognitive function in MS patients are related with impairment in upper extremity motor function. This again contributes to an impairment in physical domain of quality of life. A strong correlation of the 9-HPT with VCWS-4 supports the use of the 9-HPT as a measure of manual dexterity and gross motor functions.

Adult↗

PubMed2006

Social functioning, theory of mind and neurocognition in outpatients with schizophrenia; mental state decoding may be a better predictor of social functioning than mental state reasoning.

Few studies have directly investigated the relationship between theory of mind (ToM) deficits and social functioning in schizophrenia. At the same time, the impact of mental state decoding tasks on social dysfunction has also not yet been investigated. In this study, the relationship between theory of mind deficits and social functioning was investigated among 50 patients with schizophrenia. A mental state decoding task known as 'The Eyes test' and a mental state reasoning task 'The Hinting test' were applied to assess ToM abilities, while the Social Functioning Scale (SFS) was used to assess social functioning. Non-ToM neurocognitive tests were also given to the patients. Results of the study show how theory of mind and working memory performances of patients with good functional outcome proved to be significantly better than those of inadequately functioning patients. Results also indicate that performance on the Eyes test was the best predictor of social functioning and that negative symptoms also contributed to poor social functioning. It is concluded in this study that mental state decoding skills appear to be the most important cognitive mediator of social functioning.

Activities of Daily Living↗

PubMed1999

Correlation of preoperative myocardial function, perfusion, and metabolism with postoperative function at rest and stress after bypass surgery in severe left ventricular dysfunction.

Previous studies of dobutamine echocardiography (DE) and positron emission tomography (PET) showed similar accuracy for predicting improvement in resting wall motion after revascularization, although limited direct comparative data are available. We sought to compare the relative accuracy of detecting contractile reserve, ischemia, perfusion, and myocardial metabolism for predicting functional recovery after coronary bypass surgery in 94 consecutive patients (aged 63+/-11 years) with chronic coronary disease and depressed left ventricular function (ejection fraction 28+/-5%). PET imaging comprised rest and dipyridamole stress myocardial perfusion images, with fluorodeoxyglucose to define metabolism-perfusion mismatch. A standard dobutamine-atropine stress was used, with evaluation of low- and peak-dose echocardiographic responses. Regional function was assessed after 13+/-16 weeks at rest in 68 patients who underwent isolated coronary bypass operation without evidence of perioperative infarction, and at rest and stress in a subgroup of 29 patients. Concordance between methods for evaluating abnormal segments (ischemic, viable, and scar) and accuracy of both tests for predicting improvement in regional function were identified. Concordance between PET and DE for identifying viable or nonviable myocardium was 63% using a 16-segment model. For predicting improved resting function after surgery, the sensitivity of PET (84%) was superior to DE (69%, p<0.001), but DE was more specific (78% vs. 37%, p<0.0001) and more accurate (75% vs. 53%, p<0.001) in predicting recovery at rest. Analysis of postoperative recovery of segmental function during stress also showed the specificity of DE to exceed that of PET (89% vs. 32%, p<0.001). The accuracy of DE was enhanced by evaluation of function during stress (86%, p<0.001), but this was not altered with PET (52%, p = NS). Thus, PET is more sensitive than DE in predicting functional recovery, but DE is more specific than PET. Evaluation of left ventricular functional recovery during stress may be preferable to assessment at rest.

Cardiotonic Agents↗

PubMed2002

Additive noise, Weibull functions and the approximation of psychometric functions.

The Weibull function is frequently chosen to define psychometric functions. Tyler and Chen (Vis. Res. 40 (2000) 3121) criticised the high-threshold postulate implied by the Weibull function and argued that this function implies the assumption of multiplicative noise. It will be shown in this paper that in fact the Weibull function is compatible with the assumption of additive noise, and that the Weibull function may be generalised to the case of detection not being high threshold. The derivations rest, however, on a representation of sensory activity lacking a satisfying degree of generality. Therefore, a more general representation of sensory activity in terms of stochastic processes will be suggested, with detection being defined as a level-crossing process, containing the original representation as a special case. Two classes of stochastic processes will be considered: one where the noise is assumed to be additive, stationary Gaussian, and another resulting from cascaded Poisson processes, representing a form of multiplicative noise. While Weibull functions turn out to approximate well psychometric functions generated by both types of stochastic processes, it also becomes obvious that there is no simple interpretation of the parameters of the fitted Weibull functions. Moreover, corresponding to Tyler and Chen's discussion of the role of multiplicative noise particular sources of this type of noise will be considered and shown to be compatible with the Weibull. It is indicated how multiplicative noise may be defined in general; however, it will be argued that in the light of certain empirical data the role of this type of noise may be negligible in most detection tasks.

Contrast Sensitivity↗

PubMed1997

Flow-function relation in patients with chronic coronary artery disease and reduced regional function. A positron emission tomographic and two-dimensional echocardiographic study with coronary vasodilator stress.

OBJECTIVES: We sought to elucidate the flow-function relation in chronic postischemic dysfunction during vasodilator stress. BACKGROUND: In patients with ischemia and regional dysfunction, stress echocardiography can elicit three responses in the dysfunctioning segments: no change, improvement or worsening. The physiology underlying these responses is unclear. METHODS: Seventeen patients with ischemia and left ventricular dysfunction underwent evaluation of regional function by two-dimensional echocardiography and myocardial blood flow by positron emission tomography and 13N-ammonia. Flow (ml/min per g) and function (regional wall motion score [RWMS] from 1 = normal to 4 = dyskinetic) were evaluated both at rest and after dipyridamole (0.56 mg/kg body weight over 4 min). RESULTS: In 45 normal segments, rest to dipyridamole flow increased from 0.83 +/- 0.22 (mean +/- 1 SD) to 1.87 +/- 0.90 (p < 0.01) with a hyperkinetic contraction pattern. Among dysfunctioning segments, responders (n = 11) showed an upsloping flow-function curve during stress (i.e., increased function [RWMS rest 2.5 +/- 0.5 vs. dipyridamole 1.2 +/- 0.4] and increased flow [rest 0.69 +/- 0.30 vs. dipyridamole 1.89 +/- 1.43, p < 0.01]); nonresponders (n = 20) had a flat flow-function curve during dipyridamole (i.e., fixed function [RWMS rest and dipyridamole 2.6 +/- 0.5] and no flow increase [rest 0.64 +/- 0.24 vs. dipyridamole 0.87 +/- 0.51, p = NS): Ischemic segments (n = 9) exhibited a downsloping flow-function curve during dipyridamole (i.e., worsened function [RWMS rest 2 +/- 0.5, dipyridamole 3.1 +/- 0.6] and no significant flow change [rest 0.67 +/- 0.29 vs. dipyridamole 0.79 +/- 0.23, p = NS]). CONCLUSIONS: Myocardial segments with rest dysfunction and a contractile reserve elicitable by a vasodilator stress more often exhibit residual flow reserve, whereas segments with a fixed or worsening mechanical response during stress show a flat flow response.

Aged↗

PubMed2003

Assessing the building blocks of function: utilizing measures of functional limitation.

To better understand the health of older people, it is valuable to go beyond conventional measures of disease and self-perceived health and utilize assessments of functional status and disability. Physical decrements can be characterized at the level of organs and body systems (impairments); the organism as a whole (functional limitations); and the person in the context of the environment and its challenges (disability). To understand the dynamics of the pathway leading from disease to disability, it is critical to measure functional limitations that can be assessed through either self-report or standardized objective measures of physical performance. Both of these approaches may be used to evaluate functions such as grasping objects, walking, and climbing stairs. In aging research, measures of functional limitation are utilized as outcomes that indicate the impact of disease, impairments, and other risk factors on function. In turn, measures of functional limitation can be used to characterize the functional status of individuals and populations, and are powerful predictors of various adverse outcomes, including incident disability in people not currently disabled. Functional limitation measures add substantially to our knowledge about older populations, but further work is needed to promote their standardization and use in both clinical and research settings.

Activities of Daily Living↗

PubMed1974

Photon propagation function: a comparison of asymptotic functions.

An earlier paper asserts the logarithmic asymptotic identity of various asymptotic functions associated with the photon propagation function, including the spectral weight function and the Gell-Mann-Low function. This note exhibits explicit expressions for the deviations between pairs of functions. It is emphasized that the differences are quantitatively small, and that the various functions have common qualitative characteristics. The discussion refers to a particular method for comparing the functions, which has no special physical status. When that restriction is removed, it becomes possible to prove the general existence of a transformation of variable that will produce the Gell-Mann-Low function from the spectral weight function. This supplies a physical interpretation that has otherwise been missing in the Gell-Mann-Low approach.

Journal Article↗

PubMed2006

SNP Function Portal: a web database for exploring the function implication of SNP alleles.

MOTIVATION: Finding the potential functional significance of SNPs is a major bottleneck in understanding genome-wide SNP scanning results, as the related functional data are distributed across many different databases. The SNP Function Portal is designed to be a clearing house for all public domain SNP functional annotation data, as well as in-house functional annotations derived from different data sources. It currently contains SNP functional annotations in six major categories including genomic elements, transcription regulation, protein function, pathway, disease and population genetics. Besides extensive SNP functional annotations, the SNP Function Portal includes a powerful search engine that accepts different types of genetic markers as input and identifies all genetically related SNPs based on the HapMap Phase II data as well as the relationship of different markers to known genes. As a result, our system allows users to identify the potential biological impact of genetic markers and complex relationships among genetic markers and genes, and it greatly facilitates knowledge discovery in genome-wide SNP scanning experiments. AVAILABILITY: http://brainarray.mbni.med.umich.edu/Brainarray/Database/SearchSNP/snpfunc.aspx.

Alleles↗

PubMed2005

Improvement in protein functional site prediction by distinguishing structural and functional constraints on protein family evolution using computational design.

The prediction of functional sites in newly solved protein structures is a challenge for computational structural biology. Most methods for approaching this problem use evolutionary conservation as the primary indicator of the location of functional sites. However, sequence conservation reflects not only evolutionary selection at functional sites to maintain protein function, but also selection throughout the protein to maintain the stability of the folded state. To disentangle sequence conservation due to protein functional constraints from sequence conservation due to protein structural constraints, we use all atom computational protein design methodology to predict sequence profiles expected under solely structural constraints, and to compute the free energy difference between the naturally occurring amino acid and the lowest free energy amino acid at each position. We show that functional sites are more likely than non-functional sites to have computed sequence profiles which differ significantly from the naturally occurring sequence profiles and to have residues with sub-optimal free energies, and that incorporation of these two measures improves sequence based prediction of protein functional sites. The combined sequence and structure based functional site prediction method has been implemented in a publicly available web server.

Algorithms↗

PubMed1999

The relative influence of perceived pain control, anxiety, and functional self efficacy on spinal function among patients with chronic low back pain.

STUDY DESIGN: A prospective analysis of the relative influence of pain-specific and performance-specific cognitive variables on lifting tasks using empirically derived measures. OBJECTIVES: To determine the relative contributions of self efficacy expectancies of lifting performance, perceptions of pain control, and anxiety on actual lifting performance. SUMMARY OF BACKGROUND INFORMATION: Although patients' pain beliefs play an important role in the expression of low back pain, there is little research on the influence of performance-specific cognitions on spinal function. This study extended the scope of recent research, with findings indicating that patients with a stronger functional self efficacy expectancy--the belief that one can perform essential work tasks successfully--achieve higher levels of function than those with a low functional self efficacy expectancy. Moreover, as a performance-specific variable, functional self efficacy expectancy was hypothesized to be a better predictor of lifting than pain-specific cognitions, which presumably influence function in an indirect manner, if at all. METHODS: Before undergoing a standardized, graded lifting assessment, 100 work-disabled patients with chronic back pain rated their confidence to perform load-lifting tasks essential to their job (functional self efficacy expectancy), their ability to control and decrease pain, and psychological distress. RESULTS: Multiple regression analyses found that functional self efficacy expectancy accurately predicted lifting. It was found to be a better predictor of lifting tasks than either of the perceived pain control measures or psychological distress. CONCLUSION: Data suggest that what patients believed they could achieve accurately determined their actual spinal function, independent of their sense of control over pain or their distress. Approaches to low back disorders emphasizing perceived pain control as a central cognitive determinant of disability were unsupported.

Adult↗

PubMed2002

Delayed graft function is characterized by reduced functional mass measured by (99m)Technetium-mercaptoacetyltriglycine renography.

BACKGROUND: The mechanism that underlies delayed graft function (DGF) is still poorly defined. Previous studies using tubular function tests have shown that postischemic injury to the renal transplants results in profound impairment of paraimmunohippurate (PAH) extraction through the tubules. METHODS: Using (99m)Technetium-mercaptoacetyltriglycine ((99m)Tc-MAG3) renography and tubular function slope (TFS), a study of the tubular uptake of (99m)Tc-MAG3 was undertaken in a prospective study of renal transplant recipients with immediate graft function (IGF) and those with DGF. RESULTS: A total of 37 consecutive recipients of a cadaveric graft and 5 kidneys from living donors was evaluated within 48 hours after transplantation and in week 2, months 3 and 6, and 3 years after transplantation. In addition to the protocol scans, recipients with DGF were examined every other day until function was resumed. Repeated measurement two-way analysis of variance and a change point analysis were performed to determine the difference in the follow-up of TFS values between the two groups. Fourteen patients were classified as having DGF and 28 immediate graft function. In the DGF group, the initial TFS value was significantly lower than in the immediate graft function group (0.54 [+/-0.01] and 1.75 [+/-0.16], respectively; P=0.002), a difference that persisted for up to 3 years. Change point analysis revealed that the postischemic tubular excretion improved with time in both groups in the first 3 to 4 weeks, but both groups remained different up to 3 years after transplantation. Multivariate analysis revealed that only the cold ischemic time was an independent risk factor for a low TFS value. After the initial recovery from postischemic injury, the TFS may be used as a marker for functional renal mass. CONCLUSION: We propose that the tubular defect in DGF, as defined by (99m)Tc-MAG3 renography, is irreversible and may be a marker of initial graft function.

Adult↗