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PubMed2005

Two kinematic synergies in voluntary whole-body movements during standing.

We used a particular computational approach, the uncontrolled manifold hypothesis, to investigate joint angle covariation patterns during whole-body actions performed by standing persons. We hypothesized that two kinematic synergies accounted for the leg/trunk joint covariation across cycles during a rhythmic whole-body motion to stabilize two performance variables, the trunk orientation in the external space and the horizontal position of the center of mass (COM). Subjects stood on a force plate and performed whole-body rhythmic movements for 45 s under visual feedback on one of the four variables, the position of the center of pressure or the angle in one of the three joints (ankle, knee, or hip). The Fitts-like paradigm was used with two target amplitudes and six indices of difficulty (ID) for each of the four variables. This was done to explore the robustness of kinematic postural synergies. A speed-accuracy trade-off was observed in all feedback conditions such that the movement time scaled with ID and the scaling differed between the two movement amplitudes. Principal-component (PC) analysis showed the existence of a single PC in the joint space that accounted for over 95% of the joint angle variance. Analysis within the uncontrolled manifold hypothesis has shown that data distributions in the joint angle space were compatible with stabilization of both trunk orientation and COM location. We conclude that trunk orientation and the COM location are stabilized by co-varied changes of the major joint angles during whole-body movements. Despite the strong effects of movement amplitude and ID on performance, the structure of the joint variance showed only minor dependence on these task parameters. The two kinematic synergies (co-varied changes in the joint angles that stabilized the COM location and trunk orientation) have proven to be robust over a variety of tasks.

Adaptation, Physiological↗
PubMed1993

Confocal microscopy reveals coordinated calcium fluctuations and oscillations in synaptic boutons.

Calcium ions are one of the main factors regulating quantal transmitter release and thus synaptic transmission in the nervous system. Using confocal microscopy, fluorescent imaging with the calcium indicator Rhod-2, and time series analysis, we show that the levels of calcium ions inside single synaptic boutons of the lizard neuromuscular junction are not constant at rest, but undergo coordinated fluctuations in the space domain, which cover a large fraction of the synaptic bouton. Furthermore, oscillations in intracellular calcium were frequently observed in the time domain. Control experiments showed no coordinated fluctuations or oscillations at locations outside the synaptic boutons. Edge detection analysis showed that the coordinated fluctuations and oscillations were not due to movement artifacts. No coordinated fluctuations and oscillations were seen when similar measurements and analyses were performed on artificial fluorescent beads. A variance analysis was performed on artificial fluorescent beads and on synaptic boutons. The variance of the fluorescent signal at the synaptic boutons was larger than the variance in artificial beads with the same mean fluorescence. This extra variance was greatly reduced when the extracellular calcium concentration was decreased from 2.0 mM to 0.4 mM. We conclude that the coordinated fluctuations and oscillations in the calcium-induced fluorescence at the synaptic boutons are genuine biological phenomena and may be of significance in the regulation of transmitter release.

Animals↗
PubMed1992

The influence of casting methods on the surface microhardness and crystalline formation of aluminum-copper alloys.

The influence of air/gas, oxygen/gas, and electric casting methods on the surface microhardness and crystalline formation of three aluminum-copper alloys was verified. The inclusion, wax elimination, and casting of the pattern were accomplished by using conventional techniques for thermal expansion investment. After metalographic polishing, the surface hardness analysis was verified with a penetrator. The penetrations were transformed in Knoop hardness with the conversion table, and computed by variance analysis. The test sample surfaces were then etched with a reactive solution composed of equal parts of hydrogen peroxide and ammonium hydroxide. The crystalline grains precipitated by solution were photographed with Kodak film 32 ASA. The results demonstrated that the surface microhardness of the alloys was modified according to the heat sources used, and the crystalline grain disposition was also adversely influenced by the heat sources, with the exception of Goldent alloy.

Acid Etching, Dental↗
PubMed2003

Patterns of injury in indigenous Australians admitted to Cairns Base Hospital.

AIM: To study and compare the type and frequency of injury to indigenous and non-indigenous patients admitted to the Orthopaedic Unit at Cairns Base Hospital. METHOD AND ANALYSIS: Relevant statistics for all patients were entered or calculated: demographics, length of stay, comorbidity and complications were available. After Variance Analysis, age-standardised rates of trauma were tested using confidence intervals. RESULTS: Of 2254 admissions for trauma in 32 months, 23% were indigenous (12% of the catchment population). Upper limb injuries were significantly higher for all indigenes, these males being admitted three times as frequently as non-indigenous males. Specific lesions showed greater differences and punch injuries were prominent in both indigenous sexes. Indigenous women were much more likely to be the victims of assault or fights than other groups. CONCLUSIONS: Personal injury costs are high in the indigenous community, in human and material terms. More resources should be directed towards injury prevention.

Adult↗
PubMed2006

Actigraphic investigations on the activity-rest behavior of right- and left-handed students.

The aim of this study was to explore differences between left-and right-handed subjects in sleep duration. Sleep and activity patterns were continuously registered for 12 days using actometers on 20 left-handed and 20 right-handed medical students in Berlin. Handedness was determined by a modified version of the Edinburgh handedness inventory. Each participant wore one actometer on each wrist. Actiwatch Sleep Analysis Software (CNT, UK) was used to evaluate the data, and statistical calculations were performed with a non-parametric variance analysis. A significant difference in mean sleep duration between left-handers (7.9 h) and right-handers (7.3 h) was determined (p=0.025 for measurement made on the dominant hand and p=0.013 for ones made on the non-dominant hand). In contrast, the maximal phase of daily activity (acrophase) did not show any difference between the two groups. The difference in sleep duration might be caused by either the greater effort required for left-handers to cope in a right-handed world or by structural brain differences.

Activity Cycles↗
PubMed1983

Insulin binding to erythrocytes in children with type-I diabetes mellitus.

Specific binding of [125I]insulin to isolated erythrocytes was investigated in four groups of children (A) Healthy children under 10 years of age (n = 20) (B) Healthy children over 10 years of age (n = 13) (C) Diabetic children under 10 years of age (n = 12) (D) Diabetic children over 10 years of age (n = 63). In addition, all diabetic children (n = 75) were subdivided into four groups according to the duration of diabetes. (E) less than 2 years, (F) 2--4 years, (G) 4--6 years, and (H) greater than 6 years. By means of a nonlinear regression analysis for the extraction of binding parameters (assuming a single receptor class model with independent receptor sites) and methods of variance analysis, statistically significant differences were observed for the receptor affinities Ka (10(8) l/mol) and the receptor concentrations X0 (nmol/l) between groups A and C, B and D, C and D, but not between A and B. The affinities of groups C and D were found to be higher than the corresponding values of groups A and B, whereas the receptor concentrations exhibited an inverse behaviour. A significant increase of the receptor concentration and decrease of the receptor affinity depending on the duration of diabetes could only be proved to exist during the first 2 years of the disease.

Adolescent↗
PubMed1989

Diallel genetic analysis of the elements of paradise fish's (Macropodus opercularis L.) behavior in familiar and novel situations.

Elements of the paradise fish's ethogram were recorded in 1 familiar and 3 different unfamiliar situations and the inheritance of these behavioral elements was investigated employing a five times replicated diallel cross between 3 inbred strains. A generalized Hayman Analysis of Variance and a Variance Covariance Analysis were performed to estimate genetic effects and parameters, such as, additive genetic variance, different sorts of dominance variance, reciprocal effects, direction and degree of dominance, ratio between the frequency of dominant and of recessive alleles, minimum number of effective factors and heritabilities, etc. Knowing the genetic architecture, we make inferences about the possible evolutionary past of the behavioral elements and explain why selection might favor certain types of paradise fish's behavior in particular circumstances. In several cases a possibility of "monogenic" inheritance emerged. We explain this finding and conclude that in a cross experiment where the inheritance of phenotypical units are investigated by employing only a few genetically different strains this result may be expected.

Alleles↗
PubMed1996

Beat-to-beat QRS amplitude variability after acute myocardial infarction and coronary artery bypass grafting.

Ischemic myocardial injury has been demonstrated to be associated with increased beat-to-beat electrical variability of the depolarization phase. This can be quantified by electrocardiographic (ECG) signal variance analysis, a technique that has proven its diagnostic value in the detection of coronary artery disease (CAD). This study evaluates QRS amplitude variability during a 6-month follow-up period in 73 patients with acute myocardial infarction (AMI) and in 56 patients subjected to coronary artery bypass grafting (CABG). The beat-to-beat QRS amplitude variability was quantified with variance electrocardiography. The equipment allows computerized time domain analysis of high-fidelity ECG signals from 24 leads, and the detected electrical heterogeneity is then expressed as a nondimensional index ranging from 0 to 150, with values >90 being indicative of ischemic myocardial involvement. One week after AMI 55% of the patients presented with an abnormal QRS variability index >90. A significant (p <0.01) increase in the index values occurred during the follow-up period, but only in the patients with an initial index <70. In the CABG group 44% of the patients had a preoperative QRS variability index >90. The values increased (p <0.05) in all patients after surgery; the increase was transient in patients with an initial index <70 (p <0.01). The results demonstrate that the myocardial injury in patients with CAD is often associated with increased electrical variability of myocardial depolarization. The QRS amplitude variability index can be used as a marker of such an injury, and analysis of its changes in the course of ischemic cardiac events may provide new insights into the dynamics of ischemic heart disease and the myocardial healing process.

Aged↗
PubMedDate not supplied

[Epidemiological study of attempted suicide managed at the hospital emergency department].

PURPOSE: The authors investigate psychiatric and sociodemographic characteristics of the patients attended at the emergency department in the General Hospital of Mostoles, after their suicidal intent, and of those who repeated a suicidal intent in the first year of follow-up. METHODOLOGY: It is a prospective study, with a duration of one year, in a real sample with 119 patients randomized as a stratified sample from the population attended after their intent. Data recollection was made with a psychiatric semi-structured interview and Beck's letality and suicidal intent scales. Recruitment and follow-up periods were one year long for each of them. Statistical analysis was realized with the chi square test and Fischer's exact test to evaluate associations among cualitative variable and the variance analysis of the relations between qualitative and quantitative variable. RESULTS: Suicide intent ratio was 82/100,000 inhabitants, being in 83% by medicament ingestion. 71% were women, 66% were between 15 and 30 years old, 50% were unmarried and 12% were separated. 33% suffered from a affective disorder, and 23% were alcohol abusers. 6% of them bad a psycotic disorder. 52% of the patients had previous psychiatric disorders and 43% had been in treatment. 46% of them had someone in their families with a psychiatric disorder. 29% were repeaters after a previous attempt. Concerning to a prior contact with the Mental Health Services in the preceding month Significant differences were observed by age, but no significant differences were observed by sex. 26% used alcohol prior to the intent, mainly men. EIB and ELB ratings were significatively higher in retired than in students. Among the patients who repeated their intent (14.5%) of the followed, 78% were women, with an age between 30 and 56 years old. 61% were diagnosed having an affective disorder and 10% had psycotic disorders. 88% of the repeaters were in psychiatric treatment for five years or more.

Adolescent↗
PubMed1997

Analysis of partial variance to control for day-to-day variability in functional immune tests in depression.

Recently, analysis of partial variance (APV) was proposed as a technique to control for day-to-day variance in mitogen-induced lymphoproliferative responses whereby data obtained from controls, run in the laboratory on the same day, are used as covariates in regression analysis. In order to check the utility of the APV method in the interpretation of functional immune tests, we have reanalyzed lymphoproliferative responses in experimental subjects with depression (n = 38) stimulated by phytohemagglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A (Con A) in relation to responses obtained in laboratory controls. There were no significant relationships between the depressed patients' and laboratory controls' lymphoproliferative responses to PHA, PWM or Con A. Controlling for day-to-day variation by means of regression analysis did not significantly alter the significant relationships between the patients' lymphoproliferative responses and clinical variables, such as depressive classification and severity of illness. It is argued that the APV method may not be used to adjust for an inappropriately high day-to-day variability in immune assays.

Adult↗
PubMed1980

Genetic analysis of occlusal variation in twins.

Orthodontists usually assume that genetic factors are of major significance to the development of malocclusion. Studies of twin similarities have lent support to this concept. Use of the twin model to estimate genetic variance, however, involves the assumptions that there are no mean or total variance inequalities between monozygotic and dizygotic twins. The environmental (including biologic) differences between monozygotic and dizygotic twin development may therefore constitute a source of bias. Genetic variance and heritability were estimated for a series of arch and occlusal traits in sixty twins using recently developed methods that are unbiased by variance heterogeneity between zygosities. Heterogeneity was demonstrated for twenty of the forty traits, suggesting considerable amounts of hidden environmental determinance. Tooth-displacement means differed between monozygotes and dizygotes, indicating bias in that trait's genetic variance analysis. Significant heritability could not be demonstrated for overbite, overjet, buccal segment relation, total tooth displacement, and occlusal discrepancies in arch shape. Arch size, individual tooth displacement scores, and cross-bite show significant genetic variance, averaging only about 36 percent of the total variance of these traits.

Adolescent↗
PubMed2001

Cell cycle regulators (p21, p53, pRb) in oligodendrocytic tumors: a study by novel tumor microarray technique.

Using the novel tissue microarray technique, we studied immunohistochemical expression of cell cycle regulators p53, p21, pRb in 42 grade II oligodendrogliomas, 16 grade III anaplastic oligodendrogliomas, 10 primary and 4 recidive grade II oligoastrocytomas, 10 grade III oligoastrocytomas and 2 other grade II mixed gliomas. The p53 immunopositivity associated with malignant histology of the tumor (p = 0.01, Mann-Whitney test) and high pRb expression (p = 0.015). The p21 score associated strongly with histological grade (p < 0.001). The immunopositive tumors had a significantly higher rate of proliferation (p = 0.021). The p21 immunopositivity correlated positively with p53 immunopositivity: among the 33 p21 immunopositive tumors 30 (91%) were p53 immunopositive and only 3 were p53 immunonegative (p = 0.017). Patients with p21 immunonegative primary tumors had significantly better prognosis: among them 42 of the 46 (91%) survived, whereas only 18 of the 30 patients (60%) with p21 immunopositive primary tumors survived until the follow-up date (p = 0.0017). Statistical significance was reached in multivariate analysis as well (p = 0.01, exp(B) = 5.5). The pRb immunopositive tumors had higher proliferation rate than immunonegative tumors (p = 0.002). In multivariate variance analysis, comparing the effects of different regulatory proteins on cell proliferation, only the amount of pRb expression reached statistical significance (p = 0.004). In conclusion, the expression of p21 in oligodendrocytic tumors seems to be upregulated by p53 expression which rises with cell proliferation and malignancy as in attempt to halt cell cycle but seems to be overrun by other factors. The amount of p21 expression has independent prognostic significance and could be used in diagnosis to help the difficult evaluation of the malignancy potential of oligodendrogliomas and oligoastrocytomas.

Adolescent↗
PubMed2006

Results of a proposed breath alcohol proficiency test program.

Although proficiency test programs have long been used in both clinical and forensic laboratories, they have not found uniform application in forensic breath alcohol programs. An initial effort to develop a proficiency test program appropriate to forensic breath alcohol analysis is described herein. A total of 11 jurisdictions participated in which 27 modern instruments were evaluated. Five wet bath simulator solutions with ethanol vapor concentrations ranging from 0.0254 to 0.2659 g/210 L were sent to participating programs, instructing them to perform n = 10 measurements on each solution using the same instrument. Four of the solutions contained ethanol only and one contained ethanol mixed with acetone. The systematic errors for all instruments ranged from -11.3% to +11.4% while the coefficient of variations ranged from zero to 6.1%. A components-of-variance analysis revealed at least 79% of the total variance as being due to the between-instrument component for all concentrations. Improving proficiency test program development should consider: (1) clear protocol instructions, (2) frequency of proficiency testing, (3) use lower concentrations for determining limits-of-detection and -quantitation, etc. Despite the lack of a biological component, proficiency test participation should enhance the credibility of forensic breath test programs.

Acetone↗
PubMed2007

Integrative profiling of metabolites and proteins: improving pattern recognition and biomarker selection for systems level approaches.

Methods such as mRNA expression profiling have provided a vast amount of genomic and transcriptomic information about plants and other organisms. However, there is explicit indication that considerable metabolic control is executed on the metabolite and on the protein level including protein modifications, thereby constituting the phenotypic plasticity. Consequently, the analysis of the molecular phenotype demands the step toward mass spectrometry (MS)-based postgenomic techniques such as metabolomics and proteomics. This chapter describes a straightforward protocol for simultaneously extracting metabolites and proteins from the same biological sample in preparation for MS analysis. Furthermore, protocols for profiling polar metabolites using gas chromatography time-of-flight MS and for shotgun proteomics using liquid chromatography-MS are discussed. A practical course is laid out that outlines all the basic steps, from harvesting to data analysis. These steps enable the correlative study of metabolite and protein dynamics with minimal technical variation. Biological variability of independent samples is exploited for variance analysis and pattern recognition.

Arabidopsis↗
PubMed1979

A comparison of four methods of predicting arch length.

1. Four arch length prediction equations (Nance, Johnston-Tanaka, Moyers, and Hixon-Oldfather) were compared by examining pretreatment casts, pretreatment intraoral radiographs, and posttreatment casts of forty-one patients of mixed-dentition age. 2. A comparison of correlation coefficients and slopes of the predicted arch length versus the actual arch lengths revealed that the Hixon-Oldfather method conformed closest to the ideal. 3. No combination of the four methods produced a more accurate equation than the single most accurate method. 4. Neither the sex of the patient nor the type of occlusion affected the prediction accuracy of any of the four equations. 5. All methods tend to overpredict the arch length size by 1 to 3 mm., with the exception of the Hixon-Oldfather equation, which underpredicted by approximately 0.5 mm. 6. An analysis of the intrainvestigator error showed a very low standard error of estimate for individual tooth measurements and for the prediction values. 7. A variance analysis showed that most of the variation was due to arch length (85%), a slight amount was due to the prediction method (8%), and 6% of the variation was due to the rater. 8. A low correlation was found between space available versus actual discrepancy and space available versus actual arch length. 9. High correlation coefficients were found for the predicted arch lengths when compared with the actual arch lengths. As expected, the correlation coefficients for the predicted widths of only the canines and premolars compared with the actual widths were not quite as high.

Bicuspid↗
PubMedDate not supplied

Models of polychlorinated dibenzodioxins, dibenzofurans, and biphenyls binding affinity to the aryl hydrocarbon receptor developed using (13)c NMR data.

Quantitative spectroscopic data-activity relationship (QSDAR) models for polychlorinated dibenzofurans (PCDFs), dibenzodioxins (PCDDs), and biphenyls (PCBs) binding to the aryl hydrocarbon receptor (AhR) have been developed based on simulated (13)C nuclear magnetic resonance (NMR) data. All the models were based on multiple linear regression of comparative spectral analysis (CoSA) between compounds. A 1.0 ppm resolution CoSA model for 26 PCDF compounds based on chemical shifts in five bins had an explained variance (r(2)) of 0.93 and a leave-one-out (LOO) cross-validated variance (q(2)) of 0.90. A 2.0 ppm resolution CoSA model for 14 PCDD compounds based on chemical shifts in five bins had an r(2) of 0.91 and a q(2) of 0.81. The 1.0 ppm resolution CoSA model for 12 PCB compounds based on chemical shifts in five bins had an r(2) of 0.87 and a q(2) of 0.45. The models with more compounds had a better q(2) because there are more multiple chemical shift populated bins available on which to base the linear regression. A 1.0 ppm resolution CoSA model for all 52 compounds that was based on chemical shifts in 12 bins had an r(2) of 0.85 and q(2) of 0.71. A canonical variance analysis of the 1.0 ppm CoSA model for all 52 compounds when they were separated into 27 strong binding and 25 weak binding compounds was 98% correct. Conventional quantitative structure-activity relationship (QSAR) modeling suffer from errors introduced by the assumptions and approximations involved in calculated electrostatic potentials and the molecular alignment process. QSDAR modeling is not limited by such errors since electrostatic potential calculations and molecular alignment are not done. The QSDAR models provide a rapid, simple and valid way to model the PCDF, PCDD, and PCB binding activity in relation to the aryl hydrocarbon receptor (AhR).

Benzofurans↗
PubMed2001

The minimum speech test battery in profound unilateral hearing loss.

OBJECTIVE: Individuals with monaural hearing experience disadvantages compared with normal hearing counterparts because of the loss of the head shadow effect, the squelch effect, and binaural summation. In this study the Minimum Speech Test Battery (MSTB), a battery designed to document word recognition in bilaterally hearing impaired cochlear implant candidates, was administered to unilaterally hearing-impaired and normal hearing subjects to study its possible use in measuring hearing difficulty in monaural subjects. STUDY DESIGN: Repeated measures design with the MSTB administered in sound-field in a sound-isolated booth in 1) quiet; 2) speech toward good ear, noise (+10 dB S/N) toward impaired ear; 3) speech toward impaired ear, noise toward good ear; and 4) bilateral speech and noise. SETTING: Academic otologic practice. PATIENTS: Ten adults with normal hearing and 10 adults with normal or near-normal hearing in one ear and profound hearing loss in the contralateral ear. MAIN OUTCOME MEASURES: The MSTB, composed of the Consonant-Nucleus-Consonant (CNC) test and the Hearing In Noise Test (HINT). RESULTS: As expected, performance differences between the groups were not found in quiet conditions. Analysis of variance and regression analysis confirmed that the impaired group performed significantly worse than control subjects on HINT testing when noise was directed toward the good ear. Analysis of variance and regression analysis confirmed that the impaired group performed significantly worse than control subjects on CNC testing when noise was directed toward the good ear and in bilateral noise. CONCLUSIONS: The MSTB may be useful in measuring the hearing difficulty of patients with monaural hearing.

Adult↗
PubMed1998

Extracellular 3',5' cyclic guanosine monophosphate inhibits kainate-activated responses in cultured mouse cerebellar neurons.

The effects of extracellularly applied 3'-5' cyclic guanosine monophosphate (cGMP) on kainate responses from cultured cerebellar granule and Purkinje neurons were investigated using whole-cell and outside-out patch recording modes. Cerebellar granule cell responses to kainate were not homogeneous, nor were the effects of cGMP. Therefore, effects of cGMP are described for two groups of granule cells categorized on the basis of the underlying channel conductance estimated by variance analysis. Cells with high-noise kainate responses had average channel conductances of 5 to 7 picoseimens, whereas the average conductances of low-variance noise responses were 0.3 to 2.0 picoseimens. High-noise kainate responses were inhibited by externally applied cGMP (5-1000 microM) in a rapidly reversible and dose-dependent manner. IC50 values were estimated at approximately 150 microM cGMP for 25 microM kainate and approximately 500 microM cGMP for 100 microM kainate. Evidence that cGMP-mediated inhibition of high-noise kainate responses occurred by a competitive mechanism included the following: 1) cGMP-mediated inhibition was overcome by increasing agonist concentration. 2) The shape of kainate current-voltage (I-V) curves and their reversal potentials were unchanged in cGMP. 3) Neither the estimated conductance nor the kinetics of the kainate-activated channels was affected by cGMP. In contrast to the uniform effects of cGMP on the high-noise kainate responses, the effects on low-noise kainate responses were variable. Half of the low-noise kainate responses were inhibited by cGMP to a similar extent as the high-noise responses; however, the other 50% of cells exhibiting low-noise kainate responses appeared to be less sensitive to the cyclic nucleotide. Moreover, cGMP coapplication decreased the estimated conductances for some low-noise kainate responses and altered their noise kinetics, which suggests either that cGMP-sensitive and -insensitive kainate receptor channels are coexpressed in these cells or that cGMP-mediated inhibition is not competitive for this subgroup of glutamate receptor channels. Overall, these data indicate that there are direct inhibitory effects of extracellular cGMP on a large group of excitatory synapses in the CNS--effects that need to be taken into account when investigators utilize membrane-permeable cGMP analogs. Whether this cGMP-mediated inhibition has a functional role in brain is unknown.

Animals↗