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Results for “functionality”

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At least 1,189 records · Page 66Linked to original sources

PubMed1999

Hemodynamic characterization of a functional erection. Arterial and corporeal veno-occlusive function in patients with a positive intracavernosal injection test.

OBJECTIVES: To characterize hemodynamically a functional/rigid erection and study the hypothesis that a positive intracavernosal injection test indicates normal arterial and corporeal veno-occlusive function. METHODS: 33 patients (mean age 39.5 +/- 9 years), who developed rigid erection during pharmacocavernosometry, included in the present study. The presence of axial rigidity was determined at steady state equilibrium intracavernosal pressure, by absence of buckling to axial force of 1 kg, applied to the erect penis and sustained for >/=15 min. Arterial and veno-occlusive hemodynamic parameters were analyzed. RESULTS: Flow-to-maintain at intracavernosal pressure 150 mm Hg and mean pressure decay values ranged between 0.5-13 ml/min and 5-85 mm Hg, respectively. Flow-to-maintain values >5 ml/min were noticed in 8 patients (24. 24%), while pressure decay values >45 mm Hg in 13 patients (39.39%). Pharmacocavernosography revealed moderate opacification of venous structures in 7 cases (21.21%). Abnormal systemic-cavernosal systolic arterial pressure gradients in both cavernosal arteries were noticed in 9 patients (27.27%). All patients with flow-to-maintain values >5 ml/min had normal arterial function. CONCLUSIONS: A functional/rigid erectile response may coexist with arterial insufficiency or corporeal veno-occlusive dysfunction. Presence of normal or borderline arterial inflow may compensate minimal or moderate veno-occlusive dysfunction, resulting in a functional - but not normal - erection. Such information is critical when the intracavernosal injection test is used for diagnostic purposes.

Adult↗

PubMed2005

Growth hormone deficiency and memory functioning in adults visualized by functional magnetic resonance imaging.

Cognitive functioning, especially memory performance, is known to be impaired in patients with childhood-onset growth hormone deficiency (CO-GHD), and growth hormone substitution has been found to counteract this memory impairment. Neuropsychological and functional magnetic resonance imagining (fMRI) data acquired during a working memory task in 13 childhood-onset GH-deficient patients were compared with 13 age, sex and education level matched healthy controls. Results demonstrated that there is no difference in the quality of the performance in the working memory task between GH-deficient patients and control subjects. However, memory speed was found to be subnormal in patients. Concerning mood, patients reported more complaints of fatigue, and less vigor. Imaging data showed that patients had increased activity in dorsolateral/ventrolateral prefrontal cortex, anterior cingulate cortex, parietal cortex, supplementary motor and motor cortex, as well as in the thalamus and precuneus area. Increasing task load was also associated with an increase in brain activity in similar areas in patients compared to control subjects. In conclusion, this fMRI study shows that GH-deficient patients have a subnormal memory speed, but no impaired quality of memory performance, which may be due to compensatory recruitment of dorsal prefrontal brain regions. These findings indicate that the GH-IGF-1 axis contributes to prefrontal functioning in patients with CO-GHD.

Adolescent↗

PubMed2006

Comparison of the test of everyday functional abilities with a direct measure of daily function.

OBJECTIVES: To compare scores for dementia patients on a newly developed direct test of instrumental activities of daily living (IADLs) to scores on a widely accepted functional measure. METHODS: In 27 community-dwelling dementia patients, scores for the Test of Everyday Functional Ability (TEFA) were compared with scores on a widely used direct test of daily function (Independent Living Scale; ILS). RESULTS: Mini-Mental State Examination scores ranged from 5 to 28 (mean +/- SD = 20.7 +/- 6.37). There was a highly significant correlation between total TEFA and total ILS scores (r(25) = 0.892, p < 0.001) as well as many of the comparable subscales. CONCLUSION: The TEFA is a valid measure of IADL competence for dementia patients.

Activities of Daily Living↗

PubMed1982

Effects of hydrogen peroxide on cardiac function and post-ischaemic functional recovery in the isolated 'working' rat heart.

The effects of hydrogen peroxide on the normal and ischaemic myocardium were investigated using the isolated 'working' rat heart preparation. In the range 0-3 microM no changes in heart rate, aortic flow, coronary flow, or aortic pressure were observed. Between 3 and 30 microM, however, there was a dose-dependent fall in aortic flow and an accompanying increase in coronary flow, the total cardiac output remaining unchanged. At concentrations about 30 microM functional failure occurred. Following a 24-min ischaemic period during which time 6 microM hydrogen peroxide was infused via the aorta at a constant rate to remove any vasodilatory effect, all hearts failed to recover. In contrast, 50% of control hearts recovered pump function. In conclusion, therefore, hydrogen peroxide can reduce function in the aerobic working rat heart and may exert a vasodilatory effect. When this effect is eliminated hydrogen peroxide affords no protection during ischaemia and appears to exacerbate tissue injury.

Animals↗

PubMed1985

Survival and functional results after valve replacement for aortic regurgitation from 1976 to 1983: impact of preoperative left ventricular function.

Recent studies suggest that preoperative left ventricular function may no longer be an important determinant of survival or functional results after operation for aortic regurgitation because of improved operative techniques. To assess the effect of left ventricular function on prognosis in the current surgical era, we performed echocardiographic and radionuclide angiographic studies in 80 consecutive patients undergoing valve replacement from 1976 to 1983. No patient had associated coronary artery disease. For all patients, 5 year survival was 83 +/- 5%, significantly better than the 62 +/- 9% 5 year survival in our patients operated on from 1972 to 1976. Preoperative resting left ventricular ejection fraction (p less than .001), fractional shortening (p less than .001), and end-systolic dimension (p less than .01) were the most significant predictors of survival (univariate life-table analysis). Five year survival was 63 +/- 12% in patients with subnormal ejection fraction (n = 50) compared with 96 +/- 3% in those with normal ejection fraction (n = 30). Patients with subnormal left ventricular ejection fraction and poor exercise tolerance or prolonged duration of left ventricular dysfunction (greater than 18 months) comprised the high-risk subgroup (5 year survival 52 +/- 11%). Patients in this subgroup also had persistent left ventricular dysfunction after operation, with greater left ventricular end-diastolic dimensions and reduced ejection fraction (both p less than .001) compared with patients with normal preoperative left ventricular ejection fraction or a brief duration of left ventricular dysfunction (less than 14 months). Cold hyperkalemic cardioplegia was used for myocardial preservation in 46 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

PubMed1999

Cholesterol reduction rapidly improves endothelial function after acute coronary syndromes. The RECIFE (reduction of cholesterol in ischemia and function of the endothelium) trial.

BACKGROUND: Cholesterol lowering reduces coronary events. One mechanism could be improvement of endothelial function. In line with this hypothesis, this study investigates whether cholesterol reduction can result in rapid improvement of endothelial function after acute coronary syndromes. METHODS AND RESULTS: Patients with acute myocardial infarction or unstable angina and total cholesterol levels at admission >/=5.2 mmol/L or LDL >/=3.4 mmol/L were randomized to placebo (n=30) or pravastatin 40 mg daily (n=30) for 6 weeks. Brachial ultrasound was used to measure endothelium-dependent flow-mediated dilatation (FMD) and response to endothelium-independent nitroglycerin. Changes in the levels of markers of platelet activation, coagulation factors, and plasma endothelin levels were also assessed. Total and LDL cholesterol levels were similar at admission and before randomization in both groups. With pravastatin, but not with placebo, they decreased by 23% (P<0.05) and 33% (P<0.01), respectively. FMD was unchanged with placebo, 5.43+/-0.74% (mean+/-SEM) to 5.84+/-0.81%, but increased with pravastatin, 4.93+/-0.81% to 7.0+/-0.79% (P=0.02), representing a 42% relative increase. Responses to nitroglycerin were similar during the time course of the study in the 2 groups. Markers of platelet activity, coagulation factors, and endothelin levels were not affected by pravastatin. CONCLUSIONS: Cholesterol reduction with pravastatin initiated early after acute coronary syndromes rapidly improves endothelial function after 6 weeks of therapy.

Anticholesteremic Agents↗

PubMed2005

Reduced left ventricular functional reserve in hypertensive patients with preserved function at rest.

In many hypertensive patients, left ventricular pump function is normal at rest but abnormal during exercise. Myocardial dysfunction or altered left ventricular loading may be responsible for this finding. To verify the hypothesis of impaired myocardial functional reserve in the hypertensive heart, we assessed the response of stress-adjusted midwall shortening to graded, low-dose dobutamine infusion in hypertensive subjects with normal midwall shortening at rest. Sixty-five subjects (45 never treated hypertensive subjects and 20 normotensive volunteers comparable for age) received dobutamine at 1, 2, 3, 4, and 5 microg x kg(-1) x min(-1) for 5-minute steps; within this range of infusion rates, heart rate and systemic blood pressure were stable. Two-dimensional, M-mode, and Doppler echocardiography were performed at baseline and at the end of each step. In normotensive controls, midwall shortening increased from baseline during 2 microg x kg(-1) x min(-1) dobutamine by an average of 16+/-4.5% (P<0.01); a value of 2 standard deviations below this mean response was taken as the lower limit of normal. In the hypertensive subjects, 24 had a normal midwall shortening response to dobutamine at this dose (group I) and 21 had a subnormal response (group II). Whereas blood pressure and left ventricular mass were similar in group II and group I, the former had greater relative wall thickness (P<0.01) than the latter. beta-adrenergic stimulation by very-low-dose dobutamine unmasks subtle impairment of myocardial functional reserve in hypertensive subjects with normal myocardial performance at rest. This alteration seems to be related mainly to increase in left ventricular relative wall thickness.

Adrenergic beta-Agonists↗

PubMed2006

Long-term changes of functional MRI-based brain function, behavioral status, and histopathology after transient focal cerebral ischemia in rats.

BACKGROUND AND PURPOSE: The relation between recovery of brain function and neurological status after clinical and experimental cerebral ischemia is incompletely characterized. We assessed the evolution of ischemic injury, behavioral status, and brain activity at acute to chronic periods after transient middle cerebral artery occlusion (tMCAO) in rats. METHODS: Male Sprague-Dawley rats were subjected to 20-minute tMCAO (n=10) or sham operation (n=10). Sensorimotor behavioral testing and multimodal (diffusion, perfusion, T2, and functional) MRI, as well as postmortem hematoxylin-eosin staining, were performed before and up to 21 days after tMCAO. MRI and histological parameters were evaluated in 5 regions of interest within the sensorimotor network. Diffusion, perfusion, and T2 lesion volumes were calculated according to previously established viability thresholds. RESULTS: Diffusion and perfusion lesions were present during occlusion but disappeared completely and permanently within 30 minutes after reperfusion, with no T2 lesions seen. Functional MRI and behavioral deficits did not normalize until 1 and 21 days after tMCAO, respectively. Histology demonstrated selective neuronal cell death at 7 and 21 days after reperfusion. CONCLUSIONS: Twenty-minute tMCAO produced distinct changes on multimodal MRI, histology, and behavioral parameters acutely and chronically. Normal findings on MRI after transient ischemia may not indicate normal tissue status, as behavioral and histological anomalies remain. Behavioral dysfunction persisting long after the recovery of MRI parameters may relate to the subtle neuronal damage seen on histology. Together, these results may help explain unremitting neurological deficits in stroke or transient ischemic attack patients with normal MRI findings.

Animals↗

PubMedDate not supplied

Topographical distribution of barrier function in cervico-cephalic arteries of dog. Major cerebral arteries possess definite barrier function?

Topographic distribution of barrier function in normal canine cervico-cephalic arteries was studied using horseradish peroxidase (HRP) and Evans blue as tracers. The carotid sinus of the internal carotid artery (ICA) was conspicuously permeable to HRP when compared to other areas of major cervical arteries. The cavernous portion of the ICA also showed prominent permeation of HRP, especially through the outer surface, which is covered with venous endothelial cells. On the luminal side of the cavernous portion of the ICA, barrier deficiency was noted at angulated segments such as the carotid siphon. Intracranial segments of both ICA and vertebral arteries demonstrated incomplete barrier function of the first 1 to 4 mm from the origin of the intradural segments. These areas were considered to be transitional sites in barrier function between extra- and intracranial arteries. Focal, but definite, barrier disruption was also noted at the distal ends of the ICA and other arterial branching sites of major intracranial arteries. While opening of the interendothelial junctions was considered to be one of the mechanisms causing increased permeability in the cavernous ICA, the mechanisms for the permeation of HRP into the major cerebral arteries could not be confirmed ultrastructurally.

Animals↗

PubMed2003

Tissue-culture surfaces with mixtures of aminated and fluorinated functional groups. Part 2. Growth and function of transgenic rat insulinoma cells (betaG I/17).

Interactions of transplantable cells with synthetic polymers can influence the function of biohybrid artificial organs. This study explored growth and secretion of human insulin by betaG I/17 cells cultured on surfaces bearing diamine groups (N2), trifluoropropyl groups (F3) and mixtures of the two. Cells cultured on high-F3 and high-N2 surfaces spread well, grew rapidly and produced >1.8 mol lactate per mol glucose consumed, closely resembling cells grown on the permissive control, glass. On one mixed surface, with a molar ratio of 33 N2 groups:67 F3 groups, cells had a lower lactate/glucose ratio, adopted a rounded form, grew slowly and were quick to form emergent aggregates, similar to cultures on the inhibitory control, untreated polystyrene. Cultures on surfaces with higher F3 content secreted the most insulin and, in the case of the highest-F3 surface, showed improved responsiveness to secretagogues. Hormone secretion was roughly 50% greater when cells were grown on F3 surfaces conditioned by earlier cultures of betaG I/17. Incubation of conditioned surfaces with high concentrations of a polyclonal anti-laminin serum prior to re-plating partially abolished this improvement in secretory function. Polymers bearing trifluoropropyl groups appear to be attractive candidates for use in the artificial endocrine pancreas. Surface coatings that include laminin might promote function of transgenic insulinoma cells in vitro and in vivo.

Animals↗

PubMed1987

Longitudinal study of pulmonary function development in childhood, adolescence, and early adulthood. Development of pulmonary function.

The growth of pulmonary function between 5.5 and 25 yr of age was determined using 1,511 observations over time on 353 subjects from a representative population sample of white non-Mexican-Americans in Tucson. There was an average of 8.8 yr of follow-up, with a maximum of 12. The method used was shown to be robust for span of follow-up from 3 to 12 yr (3 to 7 observations), and the results were verified by standard statistical methods. The standard error of the estimate decreased linearly with follow-up, indicating the need for longitudinal evaluation. Respiratory symptoms and diagnoses had the biggest negative impact on growth of lung function, using FVC, FEV1, Vmax50, and size-compensated flows (Vmax50/FVC). Smoking had the next biggest negative impact. Smoking cessation was shown to have a positive impact on growth of pulmonary function. Using a second linear model to adjust for individual variability and the random variability over surveys, individual growth showed similar trends. Further negative impacts were due to parental smoking, especially as it interacts with active smoking and respiratory disease. Flows at end of follow-up (Vmax50, Vmax50/FVC) were more sensitive than FEV1 to the effects of concurrent disease and smoking, and more persistent effects of these factors in early adulthood.

Adolescent↗

PubMed1974

Functional and morphologic maturation of the superficial nephrons. Relationship to total kidney function.

The functional and morphologic pattern of superficial nephron development was studied in guinea pigs ranging in age between 2 h and 38 days. Concomitent measurements of total kidney function and glomerular counts were also performed. Superficial nephron glomerular filtration rate was found to increase from 0.92 to 19.32 nl/min. The filtration rate of the entire kidney rose from 0.19 to 1.31 ml/min. During the first 15 days of life the average rate of increase in glomerular filtration rate per nephron (0.48 nl/min.day), obtained by dividing the increase in total kidney glomerular filtration rate by glomerular number, was more than twice the observed rate of increase in the superficial nephrons (0.21 nl/min.day). During the remainder of the first month, the increase in superficial nephron glomerular filtration rate (0.97 nl/min.day) was greater than the average increase for all nephrons (0.71 nl/min.day). Thus, the initial increase in total kidney glomerular filtration rate was primarily a consequence of the activity of the deep nephrons, whereas during the ensuing period the superficial nephrons appeared to be the sole contributors to the change in total kidney glomerular filtration rate.The increase in superficial nephron glomerular filtration rate was found to correlate closely with the increase in proximal tubular length. Functional glomerulotubular balance was maintained throughout the entire period of renal maturation.

Aging↗

PubMed2006

Visuospatial processing and the function of prefrontal-parietal networks in autism spectrum disorders: a functional MRI study.

OBJECTIVE: Individuals with autism spectrum disorders typically have normal visuospatial abilities but impaired executive functioning, particularly in abilities related to working memory and attention. The aim of this study was to elucidate the functioning of frontoparietal networks underlying spatial working memory processes during mental rotation in persons with autism spectrum disorders. METHOD: Seven adolescent males with normal IQ with an autism spectrum disorder and nine age- and IQ-matched male comparison subjects underwent functional magnetic resonance imaging scans while performing a mental rotation task. RESULTS: The autism spectrum disorders group showed less activation in lateral and medial premotor cortex, dorsolateral prefrontal cortex, anterior cingulate gyrus, and caudate nucleus. CONCLUSIONS: The finding of less activation in prefrontal regions but not in parietal regions supports a model of dysfunction of frontostriatal networks in autism spectrum disorders.

Adolescent↗

PubMed2004

Effects of a functional COMT polymorphism on prefrontal cognitive function in patients with 22q11.2 deletion syndrome.

OBJECTIVE: The 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome) is associated with attentional problems and executive dysfunction, and is one of the highest known risk factors for schizophrenia. These behavioral manifestations of 22q11.2 deletion syndrome could result from haploinsufficiency of the catechol O-methyltransferase (COMT) gene, located within the 22q11 region. The goal of the present study was to examine COMT genotype as a predictor of prefrontal cognitive function in patients with 22q11.2 deletion syndrome. METHOD: Patients with confirmed 22q11.2 deletions (N=44) underwent neurocognitive testing following Val(158)Met genotyping (Met hemizygous: N=16; Val hemizygous: N=28). RESULTS: Analyses of covariance revealed that Met-hemizygous patients performed significantly better on a composite measure of executive function (comprising set-shifting, verbal fluency, attention, and working memory) than did Val-hemizygous patients. CONCLUSIONS: These data are consistent with those of previous studies in normal individuals, suggesting that a functional genetic polymorphism in the 22q11 region may influence prefrontal cognition in individuals with COMT haploinsufficiency.

Alleles↗

PubMed2001

The social functioning of persons with chronic mental illness: an empirical typology of consumers and correlates of social functioning.

This study examined the typology of consumers and correlates of their social functioning using the Social Functioning Scale (SFS). Data were obtained from 244 outpatients of two psychiatric hospitals and psychiatric ward inpatients in two general hospitals through a structured in-person interview. The typology was generated using Cluster Analysis, and the profile of each group was further examined. The results indicated that there were four distinct groups of consumers. Multiple regression analysis revealed that consumers' sex, age, education, diagnosis, behavioral problems, family caregivers' age, employment status, and overall social support were significantly associated with consumers' social functioning. The implications for previous research findings and psychiatric rehabilitation service are discussed.

Adolescent↗

PubMed2006

Questions about behavioral function in mental illness (QABF-MI): a behavior checklist for functional assessment of maladaptive behavior exhibited by individuals with mental illness.

The Questions About Behavioral Function (QABF), a 25-item rating scale, was developed to identify the function(s) of maladaptive behavior in individuals with developmental disabilities. The authors adapted it for use with individuals with serious mental illness who engage in maladaptive behavior and assessed the psychometric characteristics of the new scale (Questions About Behavioral Function in Mental Illness; QABF-MI) in a sample of 135 adults with serious mental illness from three inpatient psychiatric hospitals. Staff most familiar with each person rated each item on a 5-point Likert-type rating scale, and the ratings were subjected to a number of psychometric analyses. The results of factor analyses provided a conceptually meaningful five-factor solution: physical discomfort, social attention, tangible reinforcement, escape, and nonsocial reinforcement. Congruence between the five factors derived with the QABF-MI and the corresponding factors in the original QABF was perfect. The results indicated that the QABF-MI has robust psychometric properties and may be useful as a screening tool for determining the nature of the variables that maintain maladaptive behavior exhibited by individuals with serious mental illness.

Adaptation, Psychological↗

PubMed2003

Retinoic acid maintains differentiated cell morphology and functions in long-term cultured porcine hepatocytes: obtaining functional cells for prolonged treatments with bioartificial liver.

Porcine hepatocytes show several immunological characteristics and enzymatic activities of human liver, representing an ideal xenogenic source of cells as biological component of bioartificial liver (BAL). Isolated hepatocytes rapidly lose their specific metabolic activities and their typical morphology when cultured in the presence of serum. Since in BAL porcine hepatocytes are perfused by the patient's plasma, procedures able to minimize de-differentiation of cells could be useful for long-term treatment of acute liver failure (ALF). In this work we found that, in the presence of micromolar concentration of All trans-retinoic acid (ATRA), porcine parenchymal liver cells undergo to a lower extent the de-differentiating effects of long-term culture in the presence of serum. The evaluation of lidocaine metabolism showed that ATRA-treated cells retain specific hepatocyte function for a significantly longer time when compared to control hepatocytes. A tyrosine phosphorylation of PLC-gamma1 was observed in concomitance with the ATRA-induced maximal functional activity. An increased expression of PLC-beta3 and PKC-alpha and -beta2 was also evidentiated at the longer time points explored, when the effects of ATRA in preservation of the differentiated morphology were maximal. These results provide the first evidence that ATRA plays a differentiating role in adult porcine hepatocytes cultured under de-differentiating conditions. The administration of ATRA to isolated parenchymal cells from pig liver may provide functional hepatocytes for prolonged treatment with BAL.

Animals↗

PubMed2001

Brain plasticity for sensory and linguistic functions: a functional imaging study using magnetoencephalography with children and young adults.

In this report, the newest of the functional imaging methods, magnetoencephalography, is described, and its use in addressing the issue of brain reorganization for basic sensory and linguistic functions is documented in a series of 10 children and young adults. These patients presented with a wide variety of conditions, ranging from tumors and focal epilepsy to reading disability. In all cases, clear evidence of reorganization of the brain mechanisms of either somatosensory or linguistic functions or both was obtained, demonstrating the utility of magnetoencephalography in studying, completely noninvasively, the issue of plasticity in the developing brain.

Adolescent↗