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At least 19 recordsLinked to original sources
PubMed2003

Finger interaction during multi-finger tasks involving finger addition and removal.

The purpose of this study was to investigate changes in finger forces and their interactions in one-hand multi-finger force production tasks involving finger addition and removal. Eight male subjects were instructed to produce maximal (MVC) forces with explicitly instructed ('master') fingers. After reaching maximal force with a set of master fingers, the subjects added/removed one master finger while continuing to produce the MVC with the new group of master fingers. The non-instructed ('slave') fingers also produced forces (enslaving). Finger addition/removal led to changes in the forces of individual master fingers expected from earlier studies of maximal force production by different finger groups acting synchronously. A significant increase in the forces of remaining master fingers was observed after finger removal and a close-to-significant drop in the forces of previously recruited master fingers was observed after finger addition. These effects were larger when subjects started the task with a smaller number of explicitly involved fingers. The enslaving effects increased after finger addition while they did not change after finger removal. Forces produced by the same group of master fingers acting in different tasks showed no history-dependent effects. However, significant effects of history were seen in enslaving. These observations speak against hypotheses of more independent behaviour of effectors during their asynchronous involvement. They show that finger interaction may show effects of the history of finger involvement in a task.

Adult↗
PubMed2001

Finger-positional change in three zinc finger protein Sp1: influence of terminal finger in DNA recognition.

The connection of functional modules is effective for the design of DNA binding molecules with the desired sequence specificity. C(2)H(2)-type zinc finger proteins have a tandemly repeated array structure consisting of independent finger modules and are expected to recognize any DNA sequences by permutation, multi-connection, and the substitution of various sets of zinc fingers. To investigate the effects of the replacement of the terminal finger on the DNA recognition by other fingers, we have constructed the three zinc finger peptides with finger substitution at the N- or C-terminus, Sp1(zf223), Sp1(zf323), and Sp1(zf321). From the results of gel mobility shift assays, each mutant peptide binds preferentially to the target sequence that is predicted if the fingers act in a modular fashion. The methylation interference analyses demonstrate that in the cases of the N-terminal finger substitution mutants, Sp1(zf223) and Sp1(zf323), the N-terminal finger recognizes bases to different extents from that of the wild-type peptide, Sp1(zf123). Of special interest is the fact that the N-terminal finger of the C-terminal finger substitution mutant, Sp1(zf321), shows a distinct base recognition from those of Sp1(zf123) and Sp1(zf323). DNase I footprinting analyses indicate that the C-terminal finger (active finger) induces a conformational change in the DNA in the region for the binding of the N-terminal finger (passive finger). The present results strongly suggest that the extent of base recognition of the N-terminal finger is dominated by the binding of the C-terminal finger. This information provides an important clue for the creation of a zinc finger peptide with the desired specificity, which is applicable to the design of novel drugs and biological tools.

Base Composition↗
PubMed2003

GFP-linked zinc finger protein sp1. fluorescence study and implication for N-terminal zinc finger 1 as hinge finger.

The N-terminal zinc finger (zf) of Sp1 is referred to as the 'hinge finger', which connects the C-terminal DNA binding domain with the N-terminal activation domain. In this study, we investigated how a green fluorescent protein (GFP) linked to the N-terminal zinc finger is located spatially. The fluorescence resonance energy transfer technique and steady-state fluorescence anisotropy measurements indicate the results as follows: (1) In the binding to GC-box DNA, the geometry of the GFP domain of the GFP-linked Sp1 zinc finger is similar to that of the Ala-556-->Arg mutant. (2) The GFP-linked Sp1 zinc finger is folded more compactly in the absence of DNA (hydrodynamic volume V=78.2 nm(3)) and consequently alters the conformation at the GFP domain more extensively (DeltaV=43.6 nm(3)) upon DNA binding than the Ala-556-->Arg mutant (99.5, 14.8 nm(3), respectively). These results implicate that the N-terminal 'hinge finger' moderates various interactions of the adjacent N-terminal regulation domain with other transcriptional factors as well as DNA binding and is essential for the function of Sp1 and/or Sp/XKLF family members.

Amino Acid Substitution↗
PubMed1991

Diagnostic value of finger systolic blood pressure in the assessment of vasospastic reactions in the finger skin of vibration-exposed subjects after finger and body cooling.

To assess the severity of vibration-induced white finger (VWF), finger systolic blood pressure (FSBP) after finger cooling and after combined finger and body cooling was measured by strain-guage plethysmography for 100 vibration-exposed men and 22 healthy men. The exposed men were classified as being without VWF (EW), with mild VWF (EM), and with severe VWF (ES) according to records of blanching attacks. FSBP was significantly reduced only in the ES group after finger cooling and in the ES and EM groups after both body and finger cooling. The diagnostic sensitivity and specificity for VWF was 81.7 and 90.3%, respectively. Skin temperature measurements before and after immersion in cold water (5 degrees C, for 10 min) could not be used for the estimation of VWF severity.

Adult↗
PubMed1983

Universe of finger postures and finger dynamography. A conceptual methodological tool for assessing and recording the motor capacity of the finger.

The sum total of all postures actively possible at a joint constitutes its "universe of postures". This universe can be identified by its limits. The universe of a biarticular system like the finger can be mapped out visually, by identifying the limiting postures, plotting them as points in a graph sheet in which the postures of the MP joint are represented in the horizontal axis and the postures of the PIP joint are represented in the vertical axis, and connecting the points serially. The closed figure thus obtained represents the universe of postures of the finger and shows at a glance the motor deficits of the finger as a whole. It also remains as an objective record of the universe, available for comparison after treatment. This method of evaluation of the finger has been found to be particularly useful in assessing fingers with paralytic problems. Such a visual representation of the universe, called "dynamogram" here, can also be used for kinesiological studies.

Biomechanical Phenomena↗
PubMed2003

[Finger reconstruction by microvascular second toe-to-finger transplantation in patients with traumatic loss of all fingers].

PURPOSE: To assess the utility of second toe-to-finger transplantation with neurovascular reconstruction in patients with loss of all four digits. METHOD: Analysis of 24 toe-to-finger transplantations in 18 patients regarding over-all survival, complications and secondary procedures, sensibility, function, foot symptoms, and patient satisfaction. The original metacarpophalangeal joint was preserved in 50 % of the transplantations. In six patients, a second transplantation was performed. RESULTS: A mean follow-up of 5.8 years was available in 94 % of the patients. 92 % of the transplanted toes survived, in 38 % of the cases complications occurred followed by a secondary procedure. Two-point-sensibility was present in 62 % of the transplantations, the largest range of motion of ca. 50 degrees was obtained in the metacarpophalangeal joint. An increase in the range of motion could be achieved by preservation of the original finger joint. The mean extension lag was 37 degrees independent of the preservation of the metacarpophalangeal joint. Foot symptoms were mild in four patients, in two cases severe donor-site-problems were observed. Cold intolerance was present in 47 % of the transferred toes. Overall patient satisfaction was high with 83 % of the patients confirming their decision to undergo operative treatment. CONCLUSION: Second toe-to-finger transplantation is indicated in patients with traumatic loss of all digits. By this method, a great functional gain could be achieved as well as a high level of satisfaction. The rate of complications and possible foot symptoms should be considered. The preservation of the original metacarpophalangeal joint seems to be of importance for the function of the transplanted toe.

Adolescent↗
PubMed1992

Finger systolic blood pressure measurements after finger cooling. Using the laser-Doppler method for assessing vibration-induced white finger.

Finger systolic blood pressure (FSBP) measurements after finger and body cooling using a strain-gauge plethysmograph is a useful objective test for diagnosing Raynaud's phenomenon (RP). Body cooling, however, is uncomfortable to subjects. In this study, the measurements of FSBP after finger cooling without body cooling, using Digitmatic DM2000 (Medimatic) combined with laser-Doppler flowmetry (ALF2100 Advance), were performed in 99 vibration-exposed men (40 men without RP, 39 men with mild RP, and 20 men with severe RP) and 13 healthy controls. This method is relatively useful for assessing the severity of vibration-induced white finger (VWF).

Adult↗
PubMed1987

Difference in electromyographic response of finger flexion muscles between tonic vibration reflex and finger flexion reflex induced by finger tip vibration.

Vibratory stimulus applied to the skin of the finger tip induced flexion reflex in that finger. By using the cross-correlation function, characteristics of this reflex were compared to those of tonic vibration reflex (TVR). In the cross-correlogram between unitary electromyogram (EMG) activity in the muscle flexor digitorum superficialis and vibratory stimulus with random frequency, one mode was seen in TVR, and two modes in finger flexion reflex. The secondary mode was significantly wider than the primary mode. Thus it may originate from skin mechanoreceptors and manifest via a reflex center involving a long loop.

Adult↗
PubMed1998

Coordinated force production in multi-finger tasks: finger interaction and neural network modeling.

During maximal voluntary contraction (MVC) with several fingers, the following three phenomena are observed: (1) the total force produced by all the involved fingers is shared among the fingers in a specific manner (sharing); (2) the force produced by a given finger in a multi-finger task is smaller than the force generated by this finger in a single-finger task (force deficit); (3) the fingers that are not required to produce any force by instruction are involuntary activated (enslaving). We studied involuntary force production by individual fingers (enslaving effects, EE) during tasks when (an)other finger(s) of the hand generated maximal voluntary pressing force in isometric conditions. The subjects (n = 10) were instructed to press as hard as possible on the force sensors with one, two, three and four fingers acting in parallel in all possible combinations. The EE were (A) large, the slave fingers always producing a force ranging from 10.9% to 54.7% of the maximal force produced by the finger in the single-finger task; (B) nearly symmetrical; (C) larger for the neighboring fingers; and (D) non-additive. In most cases, the EE from two or three fingers were smaller than the EE from at least one finger (this phenomenon was coined occlusion). The occlusion cannot be explained only by anatomical musculo-tendinous connections. Therefore, neural factors contribute substantially to the EE. A neural network model that accounts for all the three effects has been developed. The model consists of three layers: the input layer that models a central neural drive; the hidden layer modeling transformation of the central drive into an input signal to the muscles serving several fingers simultaneously (multi-digit muscles); and the output layer representing finger force output. The output of the hidden layer is set inversely proportional to the number of fingers involved. In addition, direct connections between the input and output layers represent signals to the hand muscles serving individual fingers (uni-digit muscles). The network was validated using three different training sets. Single digit muscles contributed from 25% to 50% of the total finger force. The master matrix and the enslaving matrix were computed; they characterize the ability of a given finger to enslave other fingers and its ability to be enslaved. Overall, the neural network modeling suggests that no direct correspondence exists between neural command to an individual finger and finger force. To produce a desired finger force, a command sent to an intended finger should be scaled in accordance with the commands sent to the other fingers.

Adult↗
PubMed2002

Dependence of finger flexion force on the posture of the nonperforming fingers during key pressing tasks.

The influence of different positions of the nonperforming (idle) fingers on the maximal force contraction of flexion (master) fingers during key pressing tasks was investigated. Ten participants performed maximal voluntary flexion contractions with various combinations of the index, middle, ring, and little fingers while the idle fingers rested on or were lifted away from the supporting surface. The effect of idle finger posture on total finger force production of master fingers was dependent on finger combination. In general, force production by master fingers was higher when the idle fingers were lifted away from the supporting surface than when they rested on it. The average increase in total force production by master fingers caused by the lifting of idle fingers was +12.4% (from -8.3% to +30.2%). Force-production capability of individual master fingers can be facilitated (as high as 34.1%), unchanged, or depressed (as high as -29.0%) by lifting the idle fingers. The effect of idle finger posture on finger force production of master fingers led to changes in force deficit. Neural, anatomical, and mechanical factors might account for the dependence of finger flexion force of master fingers on the posture of the idle fingers.

Adult↗
PubMed2002

Finger length and distal finger extent patterns in humans.

The fingers in the adult human hand differ in length and in distal extent. The literature agrees that in the clear majority of males, the distal extent of the ring finger tends to be relatively greater (using the middle finger as standard) than the index finger. However, the results for females vary considerably, with some studies reporting that females show a similar pattern to that of males, while others suggest that the prevalence of a longer index finger is relatively or absolutely more common in females. We provide a review of the literature, and a set of data for both finger length and distal fingertip extent of the finger for a contemporary cohort of young adult females and males (n = 502). Finger length measures favor the ring finger of both sexes, with smaller between-finger differences for females than for males. However, while the distal fingertip extent favors the ring finger of both hands in males, in females the left hand shows no significant differences, and the right hand shows a small index finger advantage. Thus, the sexual dimorphism in finger measures is more strongly expressed in the distal extent of fingertips than in the length of fingers. The sex differences in distal fingertip extent derive from the index finger only, with a lesser distal extent of the index finger, relative to the middle finger, in males than in females.

Adolescent↗
PubMed2001

The effect of a fatiguing exercise by the index finger on single- and multi-finger force production tasks.

We studied the effects of fatigue, induced by a 60-s maximal isometric force production with the index finger, on multi-finger coordination and force production by the other fingers of the hand. Finger forces were measured during single- and multi-finger maximal voluntary force production (MVC) at two sites, the middle of the distal or the middle of the proximal phalanges. Two fatiguing exercises involving force production by the index finger were used, one at the distal phalanx and the other at the proximal phalanx. The MVC of the index finger dropped by about 33% when it was produced at the site involved in the fatiguing exercise. In addition, large transfer effects of fatigue were observed across sites of force application and across fingers. Force deficit increased under fatigue, especially due to a drop in the recruitment of the index finger. Under fatigue, the index finger was less enslaved during force production by other fingers. During multi-finger tasks, the percentage of total force produced by the index finger was significantly reduced after the fatiguing exercise. The principle of minimization of secondary moments was violated under fatigue. We suggest that the most impaired (fatigued) finger shows less interaction with other fingers or, in other words, is being progressively removed from the multi-finger synergy. Some of the observed changes in finger coordination suggest effects of fatigue at a central (neural) level.

Adult↗
PubMed2003

The effects of stroke and age on finger interaction in multi-finger force production tasks.

OBJECTIVE: The main purpose of this study was to investigate changes in finger interaction after stroke with strongly unilateral motor effects. Effects of age on finger interaction were also analyzed. METHODS: Sixteen stroke subjects and 16 control subjects produced maximal voluntary contractions with different finger combinations by one hand and by two hands simultaneously. Individual finger forces were measured. In multi-finger tasks, force deficit (FD) was quantified as the difference between the peak finger forces in single-finger tasks and in multi-finger tasks, while enslaving (ENSL) was quantified as forces produced by fingers that were not required to produce force. RESULTS: In stroke subjects, the peak forces produced by the fingers of the impaired hand (IH) were about 36% less than those produced by the unimpaired hand. Stroke resulted in higher ENSL and decreased FD in the IH, particularly when the index and middle fingers produced force together, while aging led to higher FD and no change in ENSL. Two-hand tasks were accompanied by an additional drop in the force of individual fingers, i.e. bilateral deficit (BD). No changes in BD were observed with age or after stroke. CONCLUSIONS: We conclude that IH function in persons after stroke is accompanied not only by a general loss of finger force but also by changes in indices of multi-finger interaction. The contrast between the significantly changed indices of one-hand multi-finger interaction and unchanged BD implies that cortical neurons mediating interhemispheric inhibition are relatively spared in unilateral stroke. SIGNIFICANCE: The study shows that stroke leads to changes not only in finger force but also in finger interaction. The conclusion on relatively spared interhemispheric projections is potentially important for therapy of hand function in stroke survivors.

Adult↗
PubMed2001

Temporal and force characteristics of fast double-finger, single-finger and hand tapping.

The purposes of this study were: (1) to provide descriptive temporal and force data for fast alternate tapping by the index and middle fingers ('double-finger mode'), and to compare it with one finger fast tapping ('single-finger mode'); (2) to determine any differences in the dynamic motor function of individual fingers with these tapping tasks; and (3) to determine any differences between the single-finger mode and tapping with the whole hand ('hand mode'). Eleven healthy males tapped force transducer(s) for 7 s as fast as possible using their dominant hand. The double-finger mode had a greater peak force and a 50% faster tapping frequency than the single-finger mode. There was no correlation between the single-finger and double-finger modes in the temporal data. Tapping with two fingers thus seems to be organized with a motor strategy that is different from that with one finger, and can possibly capture an individual's additional or different motor function. A comparison between the two fingers revealed that the index finger had a significantly faster tapping frequency, indicating the superiority of the index finger over the middle finger in terms of dynamic motor function. The hand mode had a significantly faster tapping frequency with greater peak force than the single-finger mode. A distinction is essential between these two modes.

Adult↗
PubMed1992

Adjacent zinc-finger motifs in multiple zinc-finger peptides from SWI5 form structurally independent, flexibly linked domains.

Peptides containing either one, two or three of the three zinc-finger motifs from the yeast transcription factor SWI5 have been prepared by expression in Escherichia coli. The DNA binding characteristics of these peptides were investigated, and a two-dimensional nuclear magnetic resonance (n.m.r.) study undertaken to establish the three-dimensional structures of the two-finger peptide. The peptide containing fingers 1 and 2 binds sequence specifically to two thirds of the DNA binding site recognized either by intact SWI5 or by the isolated three-finger peptide, and hence has the correct tertiary fold for DNA recognition. These results also establish the polarity of DNA binding, since the N-terminal two fingers of SWI5 bind to the 5' end of the DNA binding site. Mild proteolysis of the three-finger peptide using trypsin results in a small number of discrete products, which is consistent with the presence of three structured mini-domains. Nearly complete n.m.r. signal assignments were obtained for two peptides containing finger 2 alone or fingers 1 + 2. Comparison of two-dimensional spectra of these peptides and others clearly shows that the NOE enhancements and chemical shifts characteristic of each finger are quite insensitive to the presence or absence of neighbouring fingers. This clearly indicates that adjacent zinc-finger domains are structurally independent in these peptides from SWI5. However, there must be some steric limitations on the possible relative orientations of the fingers, and to establish limits for these a set of structures for the peptide containing fingers 1 + 2 was calculated using the YASAP simulated annealing protocol in conjunction with n.m.r.-based constraints. A more detailed description of the three-dimensional structures of finger 1 and finger 2, and their relationship to other previously determined structures of single zinc-fingers, is given in the accompanying paper.

Amino Acid Sequence↗
PubMed2003

Effect of simulated rock climbing finger postures on force sharing among the fingers.

OBJECTIVE: To study the forces applied by each finger in different joint postures simulating rock climbing gripping postures. DESIGN: Subjects in sitting posture applied fingertip forces perpendicular to horizontal force sensors in three different finger postures. BACKGROUND: Data provided by the literature indicate that middle and ring finger are commonly injured. However, no quantitative assessment of the forces applied by each finger related to the joint postures has been made. METHODS: Six elite rock climbers performed finger flexion in a single-finger task and a four-finger task. The tests were conducted in an extended posture, a curved posture (the joints belonging to the finger were flexed) and an intermediate posture (the joints were flexed, except the distal one which was fully extended). Each fingertip force was expressed in absolute value and in percentage of the maximal force capacity of the finger. RESULTS: The greater force was applied by the middle finger (20.8 N), whatever the posture. The relative involvement amounted to 105% for the ring finger in the curved posture. CONCLUSIONS: The great force applied by the middle finger and the great relative involvement of the ring finger in the curved posture seem to be the main factors of injuries of these fingers. RELEVANCE: The analysis of force sharing among the fingers during different joint postures mimicking rock climbing is essential to a better understanding of finger injuries.

Adult↗
PubMed1995

Contributions and co-ordination of individual fingers in multiple finger prehension.

The contributions and co-ordination of external finger grip forces were examined during a lifting task with a precision grip using multiple fingers. The subjects (n = 10) lifted a force transducer-equipped grip apparatus. Grip force from each of the five fingers was continuously measured under different object weight (200 g, 400 g and 800 g) and surface structure (plastic and sandpaper) conditions. The effect of five-, four-, and three-finger grip modes was also examined. It was found that variation of object weight or surface friction resulted in change of the total grip force magnitude; the largest change in finger force, was that for the index finger, followed by the middle, ring, and little fingers. Percentage contribution of static grip force to the total grip force for the index, middle, ring, and little fingers was 42.0%, 27.4%, 17.6% and 12.9%, respectively. These values were fairly constant for all object weight conditions, as well as for all surface friction conditions, suggesting that all individual finger force adjustments for light loads less than 800 g are controlled comprehensively simply by using a single common scaling value. A higher surface friction provided faster lifting initiation and required lesser grip force exertion, indicating advantageous effect of a non-slippery surface over a slippery surface. The results indicate that nearly 40% force reduction can be obtained when a non-slippery surface is used. Variation in grip mode changed the total grip force, i.e., the fewer the number of fingers, the greater the total grip force. The percent value of static grip force for the index, middle, and ring fingers in the four-finger grip mode was 42.7%, 32.5%, and 24.7%, respectively, and that for the index and middle fingers in the three-finger grip mode was 43.0% and 56.9%, respectively. Therefore, the grip mode was found to influence the force contributions of the middle and ring fingers, but not of the index finger.

Adolescent↗
PubMed1995

Finger systolic blood pressures: effects of cold provocation on the reference finger.

Finger systolic blood pressure measured after cold provocation and ischemia of a digit is used to assist in the diagnosis of vibration-induced white finger, VWF. A reduction in finger systolic blood pressure after cooling is assumed to indicate vascular dysfunction. The percentage pressure change observed in the tested finger is often corrected for whole body effects (systemic systolic pressure changes) according to the pressure change measured in a reference finger. The commonly used method of correction is based on assumptions as to the causes of any changes occurring in the reference finger. It is assumed that the reference finger is not differentially susceptible to the cold provocation of the test finger, arising from either close proximity to the cold provocation or from a vascular disorder in the reference finger. An experiment has been undertaken to investigate the repeatability, over three days, of measurements of the arm systolic pressures of both arms and the finger systolic pressures in air of four fingers of both hands. The systolic pressures of both arms and of four fingers of one hand were also measured whilst the fifth finger of the same hand was subjected to cold provocation at 10 degrees C. Twelve healthy male subjects were rested in a supine position for 15 minutes in a room at 21-24 degrees C before measurements were taken. Finger systolic blood pressures were recorded using strain gauge plethysmography. The results show that the systolic blood pressure measurements were generally repeatable, but differed with measurement location. Cold provocation of the test finger had little consistent effect on the systolic pressures measured at other locations. The results are interpreted with regard to the correction of finger systolic pressure using a reference measurement.

Adult↗