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Results for “joint quantification”

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PubMed2001

The ability of the American Joint Committee on Cancer Staging system to predict progression-free survival after radical prostatectomy.

OBJECTIVE: To examine, in a retrospective analysis of outcome based on prostate-specific antigen (PSA) levels, whether the 1992 and revised 1997 staging criteria for prostate cancer can be used to predict progression-free survival for patients after radical prostatectomy for pT2 and pT3 prostate cancer. PATIENTS AND METHODS: In all, 291 patients with a PSA determination during a 6-month interval after radical prostatectomy were analysed (mean follow-up 5.2 years). In the absence of a uniform system of pathological staging, the histopathological stage was defined according to the 1992 and 1997 American Joint Cancer Committee/Union Internationale Contre le Cancer (AJCC/UICC) tumour-nodes-metastases (TNM) staging classification. Findings were correlated with the PSA value after surgery. The subgroups of pT2 and pT3 disease were compared for the time to PSA progression, using Kaplan-Meier data analysis and the log-rank test. RESULTS: The biochemical progression-free 5-year survival rates for stage pT2 were 83% (pT2a), 81% (pT2b) and 62% (pT2c); there were no significant differences in the pT2 subgroups. The recurrence-free rates for pT3 were 79% (pT3a), 65% (pT3b) and 50% (pT3c); the actuarial recurrence-free rate was significantly different for patients with 1997 AJCC pT3a vs pT3b disease (P=0.0132). There was no significant difference in the 1992 AJCC stages pT2a vs pT2b (P=0.1232) and the recurrence-free rate was not significantly different for patients with 1992 AJCC pT3a vs pT3b disease (P=0.9). There was a significant difference in the likelihood of a PSA relapse between patients with positive and negative surgical margins (P=0.131). CONCLUSION: These results support the current revised 1997 AJCC/UICC staging system for prostate cancer. There is an urgent need to develop a pathological equivalent to the AJCC/UIC TNM clinical staging system. Greater clinical input and evaluation from different institutions are essential to reach consensus on pathological staging categories that maximize the predictability of outcome after definitive therapy. Crucial issues are the definition and quantification of extraprostatic extension and definition of surgical margin categories.

Disease Progression↗

PubMed1988

[Rupture of the rotator cuff. Quantification of indirect signs in standard radiology and the Leclercq maneuver].

The roentgenograms and the "Leclercq's manoeuvre" of 105 patients who had a shoulder arthrography were reviewed. We differentiated two groups: One with a rotator cuff tear. The other without a rotator cuff tear. The space between the acromion and the head of the humerus was measured on rotation zero degree and external rotational roentgenograms. When the acromio-humeral space was less than 8 mm, it was always correlated with a rotator cuff tear (specificity = 1). If at least tow of the following signs were present, there was in most cases a rotator cuff tear (specificity = 0.96): Sclerosed acromion. Spur of the acromion. Cystic changes around the greater tuberosity. Rounded tuberosities. Inferior gleno-humeral spur. The "Leclercq's manoeuvre" was considered positive either when there was an acromio-humeral space narrowing compared with the other side, or when there was an upward subluxation of the head of the humerus. When positive there was always a rotator cuff tear (sensibility = 0.7; specificity = 1).

Arthrography↗

PubMed1990

[Quantification of tenderness of masticatory muscle].

As more dentists diagnose and treat the patient with temporomandibular disorders, muscle palpation has been recognized as a valuable diagnostic method. But this method was depended on sensibility and experience of the operator. The purpose of this study was to establish the quantification of muscle palpation by new pressure pain threshold apparatus. Pressure pain threshold (PPT) was determined by the subject when a ramp force applied to the skin changed from "pressure" to "pain". The subjects for the experiments were 90 normal males, 100 normal females and one patient with temporomandibular disorders. Total of 12 sites, anterior temporal M., posterior temporal M., superficial portion of masseter M. and deep portion of masseter M., were measured. The results obtained were as follows: 1. The females showed lower PPT than the males. 2. No difference of PPT between right and left sides was recognized in normal subject, but the significant difference in the patient. 3. PPT of the normal subjects were significantly higher in the posterior temporal M. than the other sites and lower in the superficial portion of masseter M. than the other sites.

Facial Pain↗

PubMed1998

Occurrence of a sequence in marine cyanophages similar to that of T4 g20 and its application to PCR-based detection and quantification techniques.

Viruses are ubiquitous components of marine ecosystems and are known to infect unicellular phycoerythrin-containing cyanobacteria belonging to the genus Synechococcus. A conserved region from the cyanophage genome was identified in three genetically distinct cyanomyoviruses, and a sequence analysis revealed that this region exhibited significant similarity to a gene encoding a capsid assembly protein (gp20) from the enteric coliphage T4. The results of a comparison of gene 20 sequences from three cyanomyoviruses and T4 allowed us to design two degenerate PCR primers, CPS1 and CPS2, which specifically amplified a 165-bp region from the majority of cyanomyoviruses tested. A competitive PCR (cPCR) analysis revealed that cyanomyovirus strains could be accurately enumerated, and it was demonstrated that quantification was log-linear over ca. 3 orders of magnitude. Different calibration curves were obtained for each of the three cyanomyovirus strains tested; consequently, cPCR performed with primers CPS1 and CPS2 could lead to substantial inaccuracies in estimates of phage abundance in natural assemblages. Further sequence analysis of cyanomyovirus gene 20 homologs would be necessary in order to design primers which do not exhibit phage-to-phage variability in priming efficiency. It was demonstrated that PCR products of the correct size could be amplified from seawater samples following 100x concentration and even directly without any prior concentration. Hence, the use of degenerate primers in PCR analyses of cyanophage populations should provide valuable data on the diversity of cyanophages in natural assemblages. Further optimization of procedures may ultimately lead to a sensitive assay which can be used to analyze natural cyanophage populations both quantitatively (by cPCR) and qualitatively following phylogenetic analysis of amplified products.

Amino Acid Sequence↗

PubMed1992

Positional changes of the mandibular condyle assessed by three-dimensional computed tomography.

This investigation was designed to test the validity and reliability of three-dimensional computed tomography (3-D CT) for quantification of positional changes of the condyle in a laboratory model. The model consisted of a mounted dried human skull and a mandibular condyle attached to a micromanipulator. Controlled changes in condylar position were made and the condyle/fossa was imaged. Positional changes were measured by triangulation methods based on specific 3-D CT landmarks. The data were analyzed using descriptive statistics, analyses of variance to evaluate the sources of variability, and linear contrasts to evaluate the differences between observed and expected values. The results indicated that selection of appropriate anatomic landmarks for assessment of movement influences technique accuracy. The data also indicate that 3-D CT is most accurate in detecting inferior condylar movements. Lateral and posterior movements were assessed with less accuracy than the inferior positional changes. The clinical significance of these differences has yet to be determined.

Analysis of Variance↗

PubMed1998

Quantification of anaerobic energy production during intense exercise.

Anaerobic energy production during supramaximal exercise has been estimated from muscle metabolic changes. Based on such measurements the anaerobic energy production was determined to be 63 and 189 mmol ATP x kg(-1) d.w. for 60 and 142 s of exhaustive cycling exercise, respectively. These estimations do not, however, include release of lactate from the exercising muscles. Furthermore, the anaerobic production cannot be related to the work performed since the muscle biopsy sample may not be representative for the muscles involved in the exercise, and the total anaerobic energy production during whole body exercise cannot be determined because the mass of the muscles used is unknown. When a single muscle is exercised, the problems are minimized. With a one-legged knee-extensor exercise model, which uses a defined muscle mass, the anaerobic energy production has been estimated to be 370 mmol ATP x kg(-1) d.w. for a 192-s exhaustive exercise period. Estimated pulmonary oxygen deficit based on an energy demand extrapolated from a linear relationship between exercise intensity and oxygen uptake at submaximal exercise does not appear to represent the anaerobic energy production during whole body exercise.

Adenosine Triphosphate↗

PubMed2001

Inhibitory conditioning stimulus in transcranial magnetic stimulation reduces the number of excited spinal motor neurons.

OBJECTIVE: To study the mechanisms of amplitude attenuation caused by a transcranial magnetic conditioning stimulus. Both conventional MEPs and the recently described triple stimulation technique (TST) were applied; the latter to improve the quantification of the response size decrease. METHODS: TST uses a peripheral collision method to eliminate the effects of desynchronization of the transcranial magnetic stimulation (TMS) induced spinal motor neuron discharges. The attenuation of motor evoked potentials (MEPs) and responses to TST was studied in 10 healthy volunteers using the conditioning-test paradigm with 2 ms interstimulus intervals. RESULTS: Conventional MEPs and responses to TST demonstrated a marked attenuation by the preceding conditioning stimulus in all subjects. The ratio of MEP to TST amplitudes was the same in conditioned and unconditioned responses. CONCLUSIONS: Our findings suggest that the transcranial conditioning stimulus does not change the degrees of desynchronization of spinal motor neuron discharges, but results in a reduced number of excited alpha motor neurons. This reduction can be estimated by both MEPs and TST.

Adult↗

PubMed2005

Composite model of time-varying appearance and disappearance of neurohormone pulse signals in blood.

Blood-borne neurohormonal signals reflect the intermittent burst-like release of peptides and steroids from neurons, glands and target tissues. Hormones control basic physiological processes, such as growth, metabolism, reproduction and stress-related adaptations. Secreted molecules undergo combined diffusion, advection and irreversible elimination from the circulation. Quantification of these interdependent processes by a structurally relevant model embodying discrete event times, continuous rates of secretion and elimination, and stochastic variations poses a formidable challenge. In an experimental setting, one observes only the hormone concentrations, which comprise a time-varying composite of secretion and elimination. The number, shape and location of underlying bursts (pulses) and attendant secretion and kinetic parameters are unobserved. The ability to estimate the properties of these processes from the observed data is fundamental to an understanding of regulated hormonal dynamics. The present formulation allows objective simultaneous appraisal of discrete (pulse times) and continuous (secretion/elimination) properties of neuroglandular activity in the presence of random variability. A probability distribution is constructed for the structural parameters (secretion/elimination, pulsing), and an algorithm is developed by which one can, based upon observed hormone concentration data, make probabilistic statements about the underlying structure: pulse frequency per day, total basal (constitutive) and pulsatile secretion per day, and half-lives of elimination. The algorithm consists of the following steps: first, explicit construction of a family of sequentially decreasing putative pulse-time sets for a given neurohormone concentration time series; and then, recursive iteration between the following two: (a) for a given pulse-time set, generate a sample from the probability distribution of unknown underlying hormone secretion and elimination rates; and (b) determine whether or not a probability-based transition from one pulse-time set to another is merited (i.e., add/remove a pulse-time or stay the same). We apply this procedure illustratively to joint estimation of pulse times, secretion rates and elimination kinetics of selected pituitary hormones (ACTH, LH and GH).

Activity Cycles↗

PubMed2006

Biomechanical efficiency of wrist guards as a shock isolator.

Despite the use of wrist guards during skate- and snowboard activities, fractures still occur at the wrist or at further proximal locations of the forearm. The main objectives of this study were to conduct a human subject testing under simulated falling conditions for measurement of the impact force on the hand, to model wrist guards as a shock isolator, to construct a linear mass-spring-damper model for quantification of the impact force attenuation (Q-ratio) and energy absorption (S-ratio), and to determine whether wrist guards play a role of an efficient shock isolator. While the falling direction (forward and backward) significantly influenced the impact responses, use of wrist guards provided minimal improvements in the Q- and S-ratios. It was suggested based on the results under the submaximal loading conditions that protective functions of the common wrist guard design could be enhanced with substantial increase in the damping ratio so as to maximize the energy absorption. This would bring forth minor deterioration in the impact force attenuation but significant increase in the energy absorption by 19%, which would help better protection against fall-related injuries of the upper extremity.

Adult↗

PubMed2004

Influence of high motor unit synchronization levels on non-linear and spectral variables of the surface EMG.

The aim of this study was to investigate the influence of high degrees of motor unit synchronization on surface EMG variables extracted by linear and non-linear analysis techniques. For this purpose, spectral and recurrent quantification analysis (RQA) were applied to both simulated and experimental EMG signals. Synthetic surface EMG signals were generated with a model of volume conductor comprising muscle, fat, and skin tissues. The synchronization was quantified by the percent of discharges of each motor unit synchronized with discharges of other motor units. The simulated signals presented degrees of synchronization in the range 0-80% (10% increments) and three mean values of motor unit conduction velocity distribution (3, 4 and 5 m/s). Experimental signals were collected from the first dorsal interosseous muscle of five patients with Parkinson disease during 10s of rest and 10s of isometric voluntary contraction at 50% of the maximal force. Mean power spectral frequency (MNF) and percent of determinism (%DET) of the surface EMG were computed from the simulated and experimental signals. In the simulated signals, %DET was linearly related to the level of synchronization in the entire range considered while MNF was sensitive to changes in synchronization in a smaller range (0-20%), outside which it levelled off. The experimental results indicated that %DET was significantly higher in the resting condition (with presence of tremor; mean +/- S.E., 85.4 +/- 0.8%) than during the voluntary contraction (which partly suppressed tremor; 60.0 +/- 2.3%; P < 0.01). On the contrary, MNF did not depend on the condition (114.3 +/- 1.5 Hz and 118.0 +/- 0.8 Hz for the resting and voluntary contraction, respectively), confirming the simulation results. Overall, these results indicated that linear and non-linear analyses of the surface EMG may have different sensitivities to the underlying physiological mechanisms in specific conditions, thus their joint use provides a more complete view of the muscle status than spectral analysis only.

Action Potentials↗

PubMed1993

Wrist motions in industry.

Cumulative trauma disorders (CTDs) are disorders of the body's tendons and nerves due to repeated exertions and excessive movements. Workers in industrial tasks who have to move their hands and wrists repeatedly and/or forcefully are susceptible to CTDs. One of the major research voids in the study of occupational wrist CTDs is the lack of quantification of the relationship between the known kinematic risk factors, such as wrist angle and repetition, and CTD risk. A quantitative surveillance study was performed in industry in which workers' three-dimensional wrist motions were monitored on the factory floor. A total of 40 subjects from eight industrial plants participated in this study (20 workers in each of two risk groups, low and high). The wrist motion parameters that were monitored for each subject were position, angular velocity, and angular acceleration measures in each plane of movement (radial/ulnar, flexion/extension, and pronation/supination). Descriptive analyses of these measures indicated that generally the mean of the high-risk subjects was larger in magnitude than that of their low-risk counterparts. However, only the velocity and acceleration parameters resulted in significant differences between low- and high-risk groups. These results demonstrate the importance of dynamic components in assessing CTD risk.

Adult↗

PubMedDate not supplied

Quantification of posterior capsule tightness and motion loss in patients with shoulder impingement.

The relationship between posterior capsule tightness and dysfunction has long been recognized clinically but has not been biometrically quantified. The purpose of this study was to quantify changes in range of motion and posterior capsule tightness in patients with dominant or nondominant shoulder impingement. Measurements of posterior capsule tightness and external and internal rotation range of motion were made in 31 patients with shoulder impingement and in 33 controls without shoulder abnormality. Patients with impingement in the nondominant arm had increased posterior capsule tightness and decreased internal and external rotation range of motion compared with controls. Patients with impingement in their dominant arm had increased posterior capsule tightness and reduced internal rotation range of motion but no significant loss of external rotation range of motion compared with controls. Posterior capsule tightness in impingement patients showed a significant correlation with loss of internal rotation range of motion. Patients with shoulder impingement in their nondominant arm had a more global loss of range of motion compared with patients having impingement in their dominant arm. We believe we have described a valid clinical measurement for identifying posterior capsule tightness in patients with shoulder impingement.

Adult↗

PubMedDate not supplied

Quantification of patellar tracking using kinematic MRI.

The purpose of this study was to describe a method to quantify dynamic patellar tracking using kinematic MRI (KMRI). Twelve normal females and three patients with patellofemoral pain participated. Imaging was performed with a 1.5-T/64-MHz MR system using a fast spoiled gradient-recalled acquisition in the steady state (GRASS) pulse sequence. A nonferromagnetic positioning device permitted active, bilateral knee extension against resistance (15% bwt) from 45 degrees knee flexion to full extension. Subjects were instructed to extend their knees at a rate of 9 degrees per second, which allowed images to be obtained at 45 degrees, 36 degrees, 27 degrees, 18 degrees, 9 degrees, and 0 degrees. All images were assessed for medial/lateral patellar displacement, patellar tilt, and sulcus angle using a computer-aided system. Normal patellar motion was characterized by medial movement from 45 degrees to 18 degrees, followed by a reversal toward lateral displacement from 18 degrees to full extension. The results for patellar tilt revealed a tendency toward decreasing lateral tilt as the knee extended. Sulcus angle measurements indicated that the patella was moving to a more shallow portion of the trochlear groove (superiorly) during extension.

Adult↗

PubMed2003

A comparison of 3 hand-held dynamometers used to measure hip abduction strength.

Quantification of strength with hand-held dynamometers is commonplace. Hand-held dynamometers offer ease of use; however, previous investigations have shown much variability between repeated measures using the same dynamometer. Even less is known regarding the degree of variability between various dynamometers. Therefore, the intent of this investigation was to compare measures of hip abduction strength recorded with 3 different but commonly used hand-held dynamometers, specifically the Microfet 2 Load Cell, Jamar Hand-Held, and Dial Push-Pull Gauge. Maximal isometric hip abduction strength was recorded in 10 women (27.6 +/- 6.2 years) over 3 consecutive days using a different device each day. A significant difference in recorded force was noted between the devices (p < 0.001) as the Microfet showed significantly less force than the others. This was supported by intraclass correlation coefficients (ICCs) ranging from 0.277 to 0.688. These data suggest that consideration must be given to using the same dynamometer when quantifying strength over repeated sessions.

Adult↗

PubMed1998

The reliability of the star-excursion test in assessing dynamic balance.

Quantification of dynamic balance is often necessary to assess a patient's level of injury or ability to function in order to initiate an appropriate plan of care. Some therapists use the star-excursion test in an attempt to quantify dynamic balance. This test requires the patient to balance on one leg while reaching with the other leg. For the purpose of this study, the reach was performed in four directions. No previous researchers have attempted to evaluate the reliability of this test. Twenty healthy subjects between the ages of 18 and 35 years participated in this study. During two testing sessions, each subject was required to perform five reaching trials in four directions. Reliability estimates, calculated using the intraclass correlation coefficient (2, 1), ranged from 0.67 to 0.87. Six duplicate practice sessions were suggested to increase this range above 0.86. Task complexity may account for the moderate reliability estimates. Subjects should engage in a learning period before being evaluated on the star-excursion test.

Adolescent↗

PubMed2006

Mastication causing segmental spinal motion in common cervical orthoses.

STUDY DESIGN: In vivo fluoroscopic quantification of segmental cervical spinal motion in asymptomatic volunteers during mastication. OBJECTIVE: To quantify the degree of segmental cervical spine motion in patients during mastication and while wearing several commonly used cervical orthoses. SUMMARY OF BACKGROUND DATA: Cervical orthoses are routinely used to stabilize the cervical spine after trauma or cervical fusion and are, in some cases, prescribed to be worn at all times, including during eating. METHODS: Seven volunteers with an average age of 31 years (range, 26-42 years) had 5 seconds of continuous lateral cervical fluoroscopic imaging while they chewed gum without any cervical orthosis (control) and while wearing a soft collar turned forward then backward, a Philadelphia collar, a Miami J collar, or a two-poster brace. Still images were created from the fluoroscopy video, which allowed for quantification of the amount of segmental motion. RESULTS: All cervical collars produced statistically greater motion at occiput-C1 and C1-C2 when compared with no collar. The motion was greatest at the occiput-C1 junction and decreased to the C4 level. No motion was detected in any subject in any brace below C4. The two-poster brace produced the most segmental motion at occiput-C1 (6.3 degrees +/- 2.0 degrees) compared with the soft collar turned backwards (1.9 degrees +/- 1.9 degrees). No subject had any segmental motion below C2 in the soft collar. No segmental spinal motion was observed without a cervical brace. CONCLUSIONS: To limit upper cervical spine segmental motion during mastication, for patients with unstable cervical spines, we propose a two-poster brace with removal of the mandibular component to allow for free mandibular action. For stable spines, we propose a soft collar turned backwards. Patients should be educated with this information.

Adult↗

PubMed1994

Analysing nuclear shape as a function of relative spatial position in the femoral insertion of the medial collateral ligament.

Quantification of biological structure by morphometry facilitates the correlation of structure to biological function. To test a hypothesis concerning the correlation of a gradient in cell and nuclear shape and a corresponding gradient in mechanical stress within a ligament insertion into bone, a computerized approach was developed for quantifying mean nuclear shape as a function of position within this insertion. Three femoral insertions of the medial collateral ligament of the rabbit were prepared for histology. Commercially available software was used to measure nuclear perimeter and area by video-based planimetry on microscopic images, then custom software was used to define an overlying mesh of polygons on each insertion, to normalize the geometry of the insertion, and to calculate the mean nuclear roundness (a function of area and perimeter) for each polygon in the mesh. This approach allows the comparison of mean nuclear roundness of different polygons and among different animals that would be extremely difficult to do manually. In addition, these morphometry results can be used to correlate with functional data.

Animals↗

PubMed2000

Stretch reflex adaptation in elbow flexors during repeated passive movements in unilateral brain-injured patients.

OBJECTIVE: To evaluate the effects of repeated, externally imposed, flexion-extension movements of the elbow on the resulting stretch reflex response in hemiparetic spastic brain-injured patients. These effects were compared within a recording session and across sessions for the same subject to determine the impact of movement history on the quantification of spastic hypertonia using the stretch reflex response. DESIGN: Twenty to 30 sequential, constant velocity flexion-extension movements were applied to the impaired elbow of our cohort, with a 10-second hold interposed between flexion and extension. Movements were applied regularly at 1-minute intervals. Changes in stretch reflex responses were monitored during the applied movements. PARTICIPANTS: We examined a convenience sample of seven hemiparetic brain-injured subjects between the ages of 26 and 60 yrs, with moderate-to-severe spastic hypertonia of elbow muscles (Ashworth score 2-4/4). Subjects participated in 2 to 9 sessions. MEASURES: Elbow torque, position, velocity, and electromyograms of the biceps, brachioradialis, and triceps muscles were recorded for each flexion and extension movement. Stretch reflex torque was calculated by subtracting passive torque from total elbow torque, recorded over large amplitude movements. A linear regression analysis quantified both the initial torque response of the stretch reflex and the ensuing adaptation of the stretch reflex during sequential movements. Intersession variability was characterized both for spastic hypertonia measures and for stretch reflex adaptation. RESULTS: Repeated, externally imposed, sequential flexion-extension movements of the elbow decreased the elbow flexor stretch reflex in six of seven subjects. The mean reduction in reflex torque after 30 movements was 50% of the initial torque values (p = .001, t test vs. 0% change). Intersession stretch reflex responses for each subject were found to vary greatly (SDs of reflex torque ranged from 0.1 to 4.0 Nm), and there were also significant variations in the degree of adaptation between subjects. CONCLUSIONS: Stretch reflex adaptation must be taken into consideration when spastic hypertonia is quantified using repeated joint motion, as is often the case. The magnitude of intersession variation in spastic hypertonia measures suggests that ideally, such measurements should be made across multiple sessions before conclusions are made regarding the efficacy of spastic hypertonia interventions. This study provides quantitative evidence that repeated joint movements may have a significant short-term beneficial effect on spastic hypertonia.

Adaptation, Physiological↗