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Calf muscle stretching programs are used to increase dorsiflexion range of motion at the ankle, yet the effects of the stretching programs on the passive properties of aged calf muscles and on standing and ambulatory function have not been studied. This initial study examined the effects of an eight-week stretching program on the passive-elastic properties of the calf muscles of older women and on selected functional activities.Nineteen women aged 65-89 years with limited dorsiflexion range of motion first completed a timed agility course, a timed 10-m walk and a standing functional reach test. A dynamometer then moved the right ankle from plantarflexion to maximal dorsiflexion and back to plantarflexion at 5 deg s(-1) to measure calf muscle passive properties. The women were randomly assigned to a group that stretched three-times a week for eight-weeks (n=10) or to a control group (n=9) that did not. The tests were repeated after the stretching program.The stretching group showed increased maximal dorsiflexion range of motion, passive resistive forces (Newtons [N]), and the absorbed and retained passive-elastic energy (deg N) (P0.05). They also had decreased times for the agility course and the 10-m walk (P0.05). The functional reach test did not change for either group.The eight-week stretching program most likely increased the maximal length, length extensibility and passive resistive forces of the calf muscles. Adaptations of other ankle and leg structures also may have contributed. The passive adaptations were associated with enhanced performances of ambulatory functional activities.

Changes in connective tissues of the skeletal muscle-tendon unit (MTU) of aging animal muscles have been associated with increased passive viscoelastic properties. This study examined whether similar changes in the viscoelastic properties were present in short calf MTUs of older women in vivo. Fifteen women 68-87 years of age with short calf MTUs, as represented by limited active dorsiflexion (DF) range of motion (ROM) of < or =5 degrees, and 15 women 20-26 years of age without decreased DF ROM participated. A Kin-Com dynamometer stretched the MTU from plantarflexion to maximal DF at the slow velocity of 5 degrees s(-1) (0.087 rad s(-1)) and the fast velocity of 120 degrees s(-1) (2.094 rad s(-1)) with minimal surface electromyogram activity in the soleus, gastrocnemius, and tibialis anterior muscles. Two-way analysis of variance (ANOVA) tests for repeated measures (Velocity x Group) indicated that all women showed greater passive torque, average passive elastic stiffness, and total absorbed passive elastic energy for the fast stretch than for the slow stretch (P < 0.001). The older women had greater percent increases for the average passive torque (30%) and total absorbed passive elastic energy (26%) for the fast stretch than the younger women (P < 0.05), who had 17.5 and 13% increases, respectively. The older women had less maximal and average passive torque (Nm) and total absorbed passive elastic energy (degrees Nm), but greater average passive elastic stiffness (Nm degrees (-1)) at both stretch velocities (P < 0.001). The results indicated that short calf MTUs of older women have increased passive viscoelastic properties that could have implications for balance and ambulatory function.

Ankle equinus is the most commonly identified impairment of individuals with spastic hemiplegia (SH). However, it is not clear how equinus at the ankle may contribute to gait deviations at other joints. The purpose of this study was to determine what compensatory gait deviations may occur as a result of an imposed, unilateral equinus constraint. Gait data were collected on 12 adult subjects with and without one ankle constrained in equinus using a unique taping method. Knee extension at initial contact, knee extension in mid stance, and hip extension at terminal stance were all found to be significantly reduced on the ipsilateral side as a result of the ankle constraint. On the unconstrained or contralateral side, subjects tended to adopt a foot-flat or toe-first initial contact pattern. This study suggests that stance phase limitations in both hip and knee extension in the gait of persons with hemiplegia are not necessarily caused by limited length of the involved side hamstrings and/or hip flexors, but rather that they can occur as the result of an ankle plantarflexor contracture alone. Deviations in the contralateral foot contact pattern can also occur secondary to unilateral equinus and should not be assumed to represent bilateral involvement.

Examine the slow passive stretch and release characteristics of the calf muscles of older women with limited dorsiflexion range of motion.A cross-sectional comparative design.The passive stretch and release characteristics of the calf muscles of older women with limited dorsiflexion range of motion have not been studied.Fifteen older women (mean 79 years) with active dorsiflexionor =10 degrees and 15 younger women (mean 24 years) without limited dorsiflexion were tested. The right ankle was stretched from plantarflexion to maximal dorsiflexion and released into plantarflexion at 5 degrees /s with minimal surface EMG activity in the soleus, gastrocnemius, and tibialis anterior muscles. Length, passive-elastic stiffness and stored passive-elastic energy were examined.The older women had less maximal passive dorsiflexion, a greater initial stretch angle, and less angular change than the younger women (P0.05). The maximal passive resistive force (Newtons) of the stretch phase, and the stored passive-elastic energy ( degrees N) during both stretch and release phases were also less (P0.001). The older women had greater passive-elastic stiffness at 0 degrees and 5 degrees of dorsiflexion (P0.001).The older women had decreased calf muscle length, extensibility, maximal passive resistive force, stored passive-elastic energy, but greater angle-specific-stiffness at 0 and 5 degrees of passive dorsiflexion.Older women with limited dorsiflexion range of motion have decreased calf muscle length, passive resistive forces and stored passive-elastic energy that may impact static and dynamic standing balance activities. Greater passive-elastic stiffness within their ambulatory dorsiflexion range of motion may partially compensate for the deficits.

Hennington G, Johnson J, Penrose J, Barr K, McMulkin ML, Vander Linden DW. Effect of bench height on sit-to-stand in children without disabilities and children with cerebral palsy. Arch Phys Med Rehabil 2004;85:70–6. Objective To evaluate the effect of seat height on sit-to-stand (STS) in children with cerebral palsy (CP) and in children without disabilities. Design A mixed design (subject type by seat height) with repeated measures for seat height. Setting Motion analysis laboratory. Participants Ten children with mild CP (mean age, 10.9±2.7y) and 10 children without disabilities (mean age, 8.7±2.4y). Interventions Kinematic and force measurements of STS were completed with 6 infrared cameras and 2 forceplates. Main outcome measures Phase duration of the STS movement, amplitude and timing of ground reaction forces, and maximum head velocity during the movement. Results Children with CP took significantly longer to rise to standing (1.71s) than children without disabilities (1.24s) (F 1,18 =16.97). The extension phase of STS was also significantly longer for children with CP (.85s) than for children without disabilities (.45s) (F 1,18 =18.73). Seat height did not affect time to stand for either children with CP or children without disabilities (F 1,18 =2.82, P >.05). The duration of the extension phase, maximum horizontal and vertical velocity of the head, and maximum vertical ground reaction force were all significantly greater when children stood from the low bench height than from the higher bench height, although we found no significant differences by subject type for maximum horizontal and vertical head velocity or for maximum vertical ground reaction force. Conclusions Although children with CP were able to modify their motor programs for STS to accommodate changes in seat height as readily as nondisabled children, the speed with which they extended against gravity was slower; therefore, the total STS movement took longer for them to complete than for children without disabilities. Because the time to complete STS from the low and high bench did not differ, it would appear that time to ascend from sitting may be invariant and therefore be a motor control parameter for the STS movement.

Background and Purpose. Therapeutic stretching of the calf muscle-tendon unit is used to increase its length and to ameliorate decreased dorsiflexion range of motion (ROM), but the influence of age on the passive properties of the calf muscle-tendon unit has not been studied adequately. The purpose of this study was to examine the influence of age on length and passive elastic stiffness (PES) characteristics of the calf muscle-tendon unit when stretched through the full, available dorsiflexion ROM. Subjects. Twenty-four younger women (aged 20–39 years), 24 middle-aged women (aged 40–59 years), and 33 older women (aged 60–84 years) participated. Methods. An isokinetic dynamometer was used to passively stretch the right calf muscle-tendon unit from relaxed plantar flexion to the maximal angle of available dorsiflexion at 5°·s−1. The maximal passive resistive torque was measured, and passive angle-torque curves were constructed for a full ROM from an initial angle of passive resistive torque to the maximal dorsiflexion angle. The full ROM represented length extensibility. The average PES was calculated for this full stretch ROM and for the first half and the last half of this stretch ROM. The maximal passive dorsiflexion angle, maximal passive resistive torque, angular change for the full stretch ROM, and average PES for the full stretch ROM and the first half and the last half of the full stretch ROM were examined for group differences and their relationships with age. Results. The maximal passive dorsiflexion angle, maximal passive resistive torque, angular change for the full stretch ROM, and average PES within the last half of the full stretch ROM were less for the older women than for the younger women. Age was negatively associated with these variables. Conclusion and Discussion. Decreased maximal passive dorsiflexion ROM in older women was associated with decreased maximal passive resistive torque, decreased calf muscle-tendon unit length extensibility, and decreased average PES within the last half of their available passive dorsiflexion ROM.

Descriptive, comparative, and correlational study of nonimpaired, active women in 3 age groups.We described age-related concentric isokinetic torque of plantar flexion (PF) of active women and examined the proposal that PF torque at slow to rapid velocities would be influenced by age-related slower muscle contractile properties. We also examined the relationship of age to passive and active force characteristics of the calf muscle.Aging is associated with decreased calf muscle strength, slower muscle contractile properties, and decreased dorsiflexion (DF) range of motion. Clinical methods of measuring these changes in the calf muscles have not been described adequately.24 younger women (20 to 39 years), 24 middle-aged women (40 to 59 years), and 33 older women (60 to 84 years) performed maximal concentric PF of the right ankle from maximal passive DF at randomly ordered velocities of 30 degrees.s-1, 60 degrees.s-1, 120 degrees.s-1, and 180 degrees.s-1. The peak and mean torques and "angular delay" (degree) from the onset of movement to peak torque were examined using ANOVA. Age was correlated (Pearson product moment r) with the peak and mean torques, "angular delay," velocity at peak torque for 180 degrees.s-1, and the maximal passive DF angle and torque.The peak and mean torques decreased with increasing age and velocities. The angular delay at 180 degrees.s-1 decreased with increasing age. Age was negatively correlated with the peak and mean torques (range, r = -0.60 to -0.73), the "angular delay" at all velocities (range, r = -0.44 to -0.64), the maximal passive DF angle (r = -0.73) and torque (r = -0.60), and with the peak torque velocity at 180 degrees.s-1 (r = -0.29).The results indicate age-related changes for the concentric isokinetic torque of the calf muscles of active women. The angular delay at 180 degrees.s-1 may show changes influenced by slower muscle contractile properties. Concurrent age-related declines in passive and active calf muscle force characteristics were demonstrated.

This study investigated the relation between limb loading and selected characteristics of gait initiation in patients after stroke.Thirteen patients attending a rehabilitation clinic volunteered for the study.For the description of clinical features, patients were divided into two groups dependent on the amount of body weight shared by the involved limb during stance before gait initiation.Patients performed six trials of gait initiation with either their involved or noninvolved limb on a force platform. Peak ground reaction forces and bilateral tibialis anterior and gastrocnemius electromyographic (EMG) activity were used for group comparison.All patients showed the correct loading and unloading characteristics in the vertical and medial-lateral direction during gait initiation. Strong correlations were noted between initial limb loading and ground reaction forces during gait initiation (r = .79 to .95). Changes in ground reaction forces were significantly less (p.001) for those patients who demonstrated decreased weight bearing on their involved limb before gait initiation. These patients were also unable to generate forward momentum, as evidenced by the fore-aft ground reaction force, with the involved limb. For all patients, increased gastrocnemius activity was noted in the stance (noninvolved) limb. The data are further discussed in regard to the relationship of the interaction of bilateral EMG activity and ground reaction forces.This study suggests that there is a correlation between symmetrical weight bearing and the ability to provide those forces that generate forward momentum in the initiation of gait.

The response of periodontal ligament mechanoreceptors to mechanical stimuli was studied at different temperatures in anaesthetized cats. Recordings were made from functionally single fibres in the inferior alveolar nerve from mechanoreceptors which were located in the ligament by dissection and punctate stimulation and electrical stimulation. A thermode was used to alter and maintain small areas of periodontal ligament at temperatures ranging from thermode tip temperatures of 3 degrees C to 57 degrees C. The response to ramp-plateau mechanical stimuli applied to the tip of the crown of the canine tooth was greatest when the thermode temperature was 37.5 degrees C +/- 6.5 degrees C. The effect was similar for all receptors studied.

The purpose of this study was to identify kinetic, kinematic, and electromyographic (EMG) characteristics during sit-to-stand (STS) in healthy elderly subjects that were affected by changes in movement speed or initial starting position. Eight healthy elderly adults performed the STS movement at natural and fast speeds. Their ankles were placed in either 5 degrees or 18 degrees of dorsiflexion prior to the movement. A motion analysis system, single force plate, and EMG equipment were used to collect data on ankle, knee, and hip movement, vertical ground reaction forces, vertical and horizontal velocity of the head, and EMG activity from selected muscles. The data were further described according to three specific phases of the STS movement. Two-way analyses of variance for repeated measures were used to determine which of the kinematic, kinetic, and timing variables were affected by changing the speed of the movement or the initial ankle position. When asked to stand as fast as possible, muscle onsets and movement phases were shortened. However, when expressed as a percent of total movement time, normalized extensor muscle onsets were found to be earlier during fast movement of the task, whereas the other variables were not different. Changing the initial ankle position affected muscle onsets, duration of movement phases, and joint excursion. We conclude from these data that many of the characteristics of the sit-to-stand movement are speed invariant and therefore the STS movement is for the most part programmed.(ABSTRACT TRUNCATED AT 250 WORDS)

The development of computerized and semi-automated motion analysis systems has made the study of human motion more widely available in research and clinical settings. Although many of these systems are currently used by physical therapists, the accuracy and reproducibility of some of these systems in estimating joint angles have not been reported. In this study, the accuracy and reproducibility of angle measurements obtained by use of the Motion Analysis™ video system were evaluated under static conditions using a standard goniometer. Reflective markers placed on a goniometer were recorded by two video cameras at 17 angles, from 20 to 180 degrees, in 10-degree increments. Recordings of the goniometer were made at three locations within the field of view of the cameras. The intraclass correlation coefficient for each location tested was .99. Average within-trial variability was less than 0.4 degree at all locations. A linear regression of the system-calculated angles and reference angles for all locations had slopes near unity (ie, 1) and intercepts that were not statistically different from zero. A preliminary evaluation of the system under dynamic conditions revealed that distances were slightly underestimated, regardless of where the movement occurred within the calibration cube.

We investigated the effect of air-splint pressure on soleus muscle motoneuron reflex excitability in 18 nondisabled subjects with no history of neurological disease and 8 subjects with cerebrovascular accidents (CVAs). Motoneuron reflex excitability was assessed by measuring the percentage of amplitude (peak-to-peak measurement) change in the Hoffman reflex (H-reflex). Pressure was applied for 5 minutes, after which the air-splint was deflated. Ten H-reflexes were recorded and averaged for each subject before pressure application to obtain a baseline value. H-reflexes were also recorded at set intervals during and after pressure application. Two-way analyses of variance for repeated measures were used to compare each group's pressure and postpressure measurements with the baseline value. Significant F tests were followed by post hoc t tests. Analyses of variance were used to compare the nondisabled subjects' H-reflex recordings with those obtained for the subjects with CVAs. The nondisabled subjects demonstrated reductions of 55% at 1 minute, 52% at 3 minutes, and 40% at the fifth minute of pressure application. The postpressure measurements showed increases in the reflex amplitude at 1 and 3 minutes postpressure; however, by the fifth minute, the amplitude was not different from the baseline value. The subjects with CVAs demonstrated reductions of 41% at 1 minute, 48% at 3 minutes, and 52% at 5 minutes of pressure application. None of the postpressure measurements, however, were statistically different from the baseline value. A statistically significant difference was demonstrated between the nondisabled subjects and the subjects with CVAs at the first minute of pressure release. Air-splint pressure may be useful when a temporary decrease in muscle reflex activity is a therapeutic goal.

In a previous study we concluded that there is no olfactory-parotid salivary reflex in humans (Lee & Linden, 1991). The present study examines the olfactory-submandibular salivary reflex. Bilateral submandibular saliva was collected using custom-made collection devices for each of nine subjects. Salivary flow was measured in response to six appetizing odours: peppermint, vanilla, chocolate, beef, tomato and lemon. A significant increase in salivary flow was seen in response to each. There was no significant response to distilled water. We conclude that an olfactory-submandibular salivary reflex does exist in humans.

A study is reported in which commercial dental materials (glass-ionomers, resin-modified glass-ionomer and polyacid-modified composite resins) in the form of discs of dimensions 6 mm diameter x 1 mm thickness were prepared and exposed to natural salivas (parotid and unstimulated whole), artificial saliva and water for up to 1 year. Surface hardness was measured at various time intervals, and water sorption characteristics were determined. For all types of material, storage in artificial saliva gave specimens of lowest surface hardness by amounts that were generally significant to p0.05, whereas no differences were found between specimens stored in water or either of the natural salivas. Water sorption characteristics were found to be unaffected by the nature of the storage medium. These results contrast with some previous findings and were not expected, given the known surface reactions between salivas and glass-ionomers, or the known enzymic degradation of composite resins. They demonstrate, however, that the current widespread practise of employing pure water for storage of specimens in laboratory studies is acceptable.

To evaluate the effect of seat height on sit-to-stand (STS) in children with cerebral palsy (CP) and in children without disabilities.A mixed design (subject type by seat height) with repeated measures for seat height.Motion analysis laboratory.Ten children with mild CP (mean age, 10.9+/-2.7 y) and 10 children without disabilities (mean age, 8.7+/-2.4 y).Kinematic and force measurements of STS were completed with 6 infrared cameras and 2 forceplates.Phase duration of the STS movement, amplitude and timing of ground reaction forces, and maximum head velocity during the movement.Children with CP took significantly longer to rise to standing (1.71 s) than children without disabilities (1.24 s) (F(1,18)=16.97). The extension phase of STS was also significantly longer for children with CP (.85 s) than for children without disabilities (.45 s) (F(1,18)=18.73). Seat height did not affect time to stand for either children with CP or children without disabilities (F(1,18)=2.82, P.05). The duration of the extension phase, maximum horizontal and vertical velocity of the head, and maximum vertical ground reaction force were all significantly greater when children stood from the low bench height than from the higher bench height, although we found no significant differences by subject type for maximum horizontal and vertical head velocity or for maximum vertical ground reaction force.Although children with CP were able to modify their motor programs for STS to accommodate changes in seat height as readily as nondisabled children, the speed with which they extended against gravity was slower; therefore, the total STS movement took longer for them to complete than for children without disabilities. Because the time to complete STS from the low and high bench did not differ, it would appear that time to ascend from sitting may be invariant and therefore be a motor control parameter for the STS movement.

During the course of a study on the morphology of periodontal ligament mechanoreceptors it was observed that a direct relation, without intervening bone, existed between the mandibular canine and first premolar tooth roots in the cat. An area, representing a window in the alveolar septal bone, extended 2–3 mm from the apex towards the tooth crown. Ruffini nerve terminals were observed amongst the collagen bundles in the ligament between the roots of the two teeth. Light and electron microscopy were used to identify the receptors. It is proposed that a periodontal ligament mechanoreceptor can respond to forces applied to adjacent teeth; movement of both teeth need not occur. This may explain the observation made in the past that single periodontal ligament mechanoreceptors respond to forces applied to more than one tooth.

A correlative morphological study was carried out on two electrophysiologically identified and located periodontal ligament mechanoreceptors in anaesthetised cats. One mechanoreceptor had its cell body in the mesencephalic nucleus and the other had its cell body in the trigeminal ganglion. Physiological recordings were made from each of their cell bodies. The two receptors were located by punctate and electrical stimuli in the labial aspect of the periodontal ligament of the left mandibular canine tooth. Both receptors had similar positions relative to the tooth apex and fulcrum and were situated in the labial part of the ligament in each tooth. The receptor loci were marked, and these regions were studied in a series of semi-thin and ultra-thin sections. Only Ruffini nerve endings were observed under each ink mark. Both Ruffini nerve endings branched, were unencapsulated and were incompletely surrounded by terminal Schwann cells with extensions projecting towards collagen bundles. The results indicate that periodontal ligament mechanoreceptors with cell bodies in the mesencephalic nucleus and those with their cell bodies in the trigeminal ganglion can both be Ruffini nerve endings. Furthermore, there was no apparent morphological difference between the two periodontal ligament mechanoreceptors.

1. In anaesthetized cats the left maxillary and mandibular canine and incisor teeth were extracted. Nine weeks later the animals were anaesthetized again and titanium implants were placed into the edentulous ridge of the maxilla and mandible. 2. Terminal experiments were performed between 9 weeks and 10 months after inserting the implants. Recordings were made from the trigeminal ganglia and peripheral nerves of anaesthetized cats. Neurones were identified which responded to forces applied to the maxillary teeth but none was found which responded to forces applied to the implant. 3. The responses of motor units in the temporalis muscle were studied in response to ramp-plateau forces applied to the maxillary canine tooth and maxillary implant using peristimulus time histograms and cumulative sum (cusum) analysis. A small amount of inhibition of the motor units was observed in response to the applied forces to the implant. However, the inhibition was much more profound when similar forces were applied to the tooth. 4. The results confirm that when forces are applied to a tooth, periodontal mechanoreceptors are stimulated which evoke reflex inhibitions to motor units in the jaw-closing muscles. However, there is evidence that mechanoreceptors situated distant to the periodontium can also evoke such reflexes. 5. The results are discussed in relation to the overall functional role of periodontal mechanoreceptors in the reflexes of mastication.

Background and Purpose. The purpose of this study was to investigate the effects of kinetic feedback frequency and concurrent kinetic feedback on the performance and learning of an isometric force production task in young, nondisabled adults. Subjects. Twenty-four nondisabled, right-hand–dominant adults (18 male, 6 female), aged 19 to 33 years (X=22.5, SD=4.1), participated in this study. Methods. Eight subjects in each of three kinetic feedback groups performed an isometric elbow extension task in an attempt to minimize error between their effort and a force template over a 5-second period. Feedback was provided (1) concurrently with and after each attempt (concurrent feedback), (2) after each attempt (100% feedback), or (3) after every other attempt (50% feedback). Immediate and delayed (48-hour) retention tests were performed without feedback. Separate analyses of variance for repeated measures were used to compare task error among the three feedback groups for acquisition, immediate retention, and delayed retention trials. Results. A significant interaction was found during the acquisition trial blocks, but at each trial block, subjects in the concurrent feedback group exhibited less error than did the subjects in either the 50% or 100% feedback group during the acquisition trials. For the immediate retention test, the 50% and 100% feedback groups exhibited 58% and 39% less error, respectively, than did the concurrent group. For the delayed retention test, the 50% and 100% feedback groups exhibited 52% and 26% less error, respectively, than did the concurrent group. In the immediate and delayed retention tests, subjects in the 50% feedback group displayed less error (31% and 36%, respectively) than did the 100% feedback group. Conclusion and Discussion. When permanent changes in the performance of a motor task are desired, concurrent feedback about task performance may be less desirable than feedback that is provided after the task has been completed. In addition, when feedback was used after the task had been completed, a lower frequency of feedback resulted in more permanent changes in the subjects' ability to complete the task.

Muscle length influences the contractile properties of muscle in that when muscle is lengthened the relaxation phase of the muscle twitch is prolonged and when muscle is shortened, the relaxation phase is shorter in duration. As a result, the force exerted by active motor units varies with muscle length during voluntary contractions. To determine if motoneuron spike trains were adjusted to accommodate for changes in the contractile properties imposed by shortened and lengthened muscle, motor unit action potentials were recorded from the tibialis anterior muscle at different muscle lengths. Twenty subjects performed isometric ramp contractions at ankle angles of 20° dorsiflexion, neutral between dorsiflexion and plantar flexion, and 30° plantar flexion, which put the tibialis anterior muscle in a shortened, neutral, or lengthened condition, respectively. During isometric contractions where torque increased at 5% MVC/s, motor unit discharge rate at recruitment was greater in shortened muscle than in lengthened muscle (P

Physical therapists often use transitional postures such as half-kneeling to help children with movement dysfunction attain an upright posture. Little is known, however, about how healthy children activate lower extremity muscles to move the hip, knee, and ankle joints as they move from kneeling through half-kneeling to stand up against gravity. The purpose of this study was to describe movement from kneeling to standing in 10 healthy 5- to 7-year-old children. Electromyography was used to record the activity of four lower extremity muscles. Cinematography was used to record joint motion of the hip, knee, and ankle of the leg initiating movement, in addition to trajectories of specific anatomical landmarks as the children rose from a kneeling to a standing position. Greater active range of motion of the hip, knee, and ankle was necessary to move from a kneeling to a standing position using the half-kneel transitional posture than is required during normal gait. The activation patterns of the gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris muscles of the leg initiating movement exhibited variability among subjects during the kneel-to-stand movement. Maximum joint range of motion and position of the hip, knee, and ankle joints at specific points in the movement exhibited less variability than patterns of muscle activation. The results showed that movement from a kneeling to a standing position in healthy children is quantifiable and can be used to help determine what normal components of movement are necessary to successfully master this movement against gravity that is antecedent to ambulation. Further studies are needed to investigate antigravity movement in younger children and in children with movement dysfunction to more fully understand normal and abnormal movement in children.

Eine apparativ ausgefuhrte gynakologische Cytodiagnostik erscheint heute mit Durchflusfluorescenzcytophotometern in den Bereich des praktisch Moglichen geruckt zu sein (z.B. mit dem Impulscytophotometer ICP 11 der Firma Phywe/Gottingen). Entscheidendes Kriterium der Auswertung ist der in Tumorzellen abnorm hohe DNS-Gehalt (Desoxyribonukleinsauregehalt) der Zellkerne. Der gemessene DNS-Gehalt einer Zellprobe wird in Form eines Histogramms ausgeschrieben. Uber die Ergebnisse einer impulscytophotometrischen Analyse von 22 verschiedenen Zellsuspensionen von der Cervix uteri wird berichtet. Darunter waren 8 Falle normaler Plattenepithels (Cyclusphasen, Graviditat, Postmenopause). Die restlichen 14 Falle stammten von Prakanzerosen und invasiven Carcinomen. Es wird bestatigt, das Zellsuspensionen mit malignen Plattenepithelien von Dysplasien, Oberflachencarcinomen und invasiven Carcinomen der Cervix uteri in den Histogrammen an dem groseren Anteil von Zellen mit erhohtem DNS-Gehalt zu erkennen sind. Die Meszeit ist hochstens minutenlang. Der Arbeitsaufwand fur die praparativen Vorarbeiten betragt vorerst noch etwas mehr als 2 Std. Der Prozentsatz nicht verwertbarer Histogramme lag bei 36%. Mit dem Impulscytophotometer lassen sich wahrscheinlich bessere Ergebnisse erzielen, wenn die Zahl der nicht verwertbaren Histogramme reduziert wird und evtl. ein anderer Fluorescenzfarbstoff eingesetzt wird. Fur die Bestimmung der Rate falsch negativer Histogramme ist das Festlegen der kritischen Zellzahl notig. Das heist: wie hoch mus der Anteil maligner Zellen in einer Mesprobe sein, um im Histogramm sicher erfast zu werden. Diese kritische Zellzahl ist vermutlich fur Dysplasien, Oberflachencarcinome und invasive Carcinome ungleich hoch. Die Ultraschallapplikation vor der Messung hat sich bewahrt. Ein differenzierter Einsatz dieses praparativen Hilfsmittels ist anscheinend erforderlich. Die Computerauswertung der Histogramme wird kunftig die Aussagesicherheit der DNS-Messungen erhohen.

Mathematical models for the analysis of pulse-cytophotometric (PCP) data are described. With computer programs based on these models the fractions of cells in G1-, S- and (G2 + M)-phase are obtained. The methods are applied to PCP-measurements of Ehrlich ascites tumor cells, human bone marrow cells and L-929-cells in culture. The results of the L-cell experiment are compared with autoradiographic results; for both methods the duration of the various phases has been calculated. Two different mathematical models for PCP-data evaluation and the autoradiographic method yielded results agreeing within statistical error. The application of the two models on different types of DNA-histograms is discussed: One model is suitable for asynchronous cell populations with a low fraction of S-phase cells, the other can be applied for partially synchronized cells and high S-phase fractions as well.

The proliferation parameters of the Walker carcinoma were estimated from both in vivo and in vitro measurements. tthe transplantable Walker carcinoma 256 was grown in male inbred BD1 rats. During exponential growth, 5--6 days after transplantation, a PLM curve was performed, yielding estimates of TC approximately equal to 18-0 hr, TS approximately equal to 6-4 hr, TG2+M approximately equal to 4-1 hr. With the double labelling technique in vitro under 2-2 atm oxygen we obtained: TC approximately equal to 18-2 hr, TS approximately equal to 8-2 hr, TG2+M approximately equal to 2-0 hr. From pulse cytophotometry DNA content histograms the fractions of cells in the cell cycle phases were calculated using a computer program: fG1 approximately equal to (47-6 +/- 1-1)%, fS approximately equal to (34-1 +/- 1-0)%, fG2+M approximately equal to (18-3 +/- 1-5)%. These fractions remained constant between the fifth and the twelfth day after transplantation. At that time the tumour growth had already slowed down appreciably. The growth fraction determined by repetitive labelling was 0.96 on the fifth and 0-93 on the seventh and eleventh day. The cell loss factor was phi approximately equal to 17% during exponential tumor growth and increased to about 100% between the tenth and twelfth day. The agreement of the cell kinetic data determined by autoradiography from solid tumours in vivo (PLM, continuous labelling) and autoradiography as well as pulse cytophotometry from in vitro experiments (excised material) was satisfactory.

The DNA content of blood cells from 17 patients with leukaemic non-Hodgkin's lymphomas of low-grade malignancy according to the Kiel classification [13] was determined by a flow-cytometric assay and compared with cytological findings. The histograms from eight patients with chronic lymphocytic leukaemia (CLL), two patients with prolymphocytic leukaemia (PL), two patients with hairy cell leukaemia (HCL), and one patient with immunocytoma (IC) showed unimodal DNA distributions falling in with a diploid DNA content (2c) of the cells. Bimodal histograms were found in one case of CLL (Rai IV) with marked leukocytosis, in one case of Sezary syndrome with small and some large Lutzner cells, and in one case of IC with “prolymphocytoid” transformation. In the case of the CLL (Rai IV) the two peaks of the histogram represent a large population of probably diploid cells (88%) and a small one of G2 cells (3%), while 9% of the lymphocytes were found in the DNA synthesis phase. Large Lutzner cells of the patient with Sezary syndrome comprising 4% of the blood cells could be identified as hypotetraploid (3,5 c), whereas small Lutzner cells (44% of all cells) were recorded at 2c. The transformed IC which evolved from a lymphocytic ] type with small, crystalloid immunoglobulin bearing cells was characterized by 84% tetraploid (4c) cells in the blood. Their large and indented nuclei exhibited a relatively dense chromatin pattern and large nucleoli that were easily recognized in semithin and ultrathin sections but not in blood films. Since cells in DNA synthesis phase were absent, the hyperploid elements in the case of the Se-zary syndrome and the transformed IC had to be regarded as non-proliferating in blood. The tetraploid “prolymphocytoid” cells of the patient with IC can be interpreted to reflect increased malignancy.

Das Knochenmark der Ratte wurde impulscytophotometrisch, histologisch und cytologisch nach Daunomycinapplikation untersucht. 24 Std p.i. zeigt sich impulscytophotometrisch eine Ansammlung von Zellen in der G2-Phase (29% Zellen in G2 + M gegenuber 12% bei den Kontrollen) und eine Abnahme der G1-Zellen auf 53% gegenuber 65% bei den Kontrollen. Die Verminderung des Anteils der Zellen in G1 hat als morphologisches Substrat eine auffallende Reduzierung kernhaltiger Vorstufen der Erythropoese. Der G2-Block wird morphologisch nicht erkannt. Im weiteren Verlauf (48–120 Std p.i.) sieht man impulscytophotometrisch eine Vermehrung des Anteils von Zellen in der S-Phase. Dieser Befund wird als Regenerationsphanomen nach Cytostaticawirkung gedeutet und geht morphologisch mit einem promyelocytaren Knochenmarksbefund einher.

Summary Cell doubling time, DNA distribution pattern, frequency distribution of chromosome numbers per cell and degree of synchrony obtained after mitotic selection were studied in 4 different sublines of mouse fibroblast cells, NCTC L-929, in culture. The 4 sublines did not differ with respect to their cell kinetic data but showed changes of the chromosome pattern compared to the stemline and compared to each other suggesting that chromosome analysis provides a very sensitive means to detect evolutianary changes of a permanent cell line.

Radiography is an important tool in the diagnosis of periodontal bone lesions. Due to subjective factors in the interpretation by the observer, however, an error-free diagnosis of bone lesions in an early stage is very difficult. The aim of this study was to reduce the influence of observer subjectivity by means of computer-assisted image processing and pattern recognition in dental radiographs. The findings of the study show that periodontal lesions can be recognized and described in an objective way by means of digitized pattern recognition.

Diagnosis of hone lesions on dental radiographs can be difficult due to the irregular trabecular pattern and subjectivity on the part of the observer. The purpose of this study is to improve the recognition of bone lesions by means of objective computer-aided pattern recognition techniques. This article describes a method for the separation of teeth and bone regions in the image to facilitate further analysis, especially of the interdental bone.

Mouse fibroblast L-929 cells synchronized by mitotic selection were irradiated during the G1-phase of the cell cycle with a dose of 1000 rad. The rate of DNA synthesis was measured by3H-thymidine incorporation, and the progression of the cells through the cell cycle was determined using a pulse-cytophotometer. Irradiation caused a decrease in the rate of DNA synthesis to half the control value, and an extension of the S-phase to twice its normal duration.

Mouse fibroblasts, subline L-929 F were synchronized by mitotic detachment. The synchronized cell cultures were irradiated with 200 kVp X-rays at different time after mitosis, and age response functions and dose effect curves were determined using the colony test. The cell age in the mitotic cycle was obtained from a computer analysis of flow cytometric DNA histograms. Both intrinsic radiosensitivity 1/D0 and extrapolation number n were found to vary during the cell cycle. The D0 has a maximum value of 176 +/- 1 rad in the middle of G1 phase and minimum of 71 +/- 1 rad at the S/G2 transition, while the extrapolation number is rather constant from the beginning of G1 phase (1.9 +/- 0.1) to the middle of S phase (2.3 +/- 0.1) and reaches a steep maximum of 9.3 +/- 1.1 at S/G2 transition. The values of n in the various phases of cell cycle are compared with the respective values of the recovery factor gamma determined after fractionated irradiation. --Cell survival after a single dose of 616 rad has minima for irradiation at G1/S transition and in early G2 phase; the survival in early G2 being about 40 times smaller than in early G1 phase. Implications for a cell cycle specific therapy are discussed.

THE detection of growth fraction and the characterisation of non-proliferating cells are extremely important in human tumour therapy1,2. Cytological criteria for individual objective discrimination in vivo between non-proliferating and proliferating cells with the same DNA content have not been previously available3. It has been shown recently, in vitro, that the transition from the non-proliferating to proliferating state (G0—G1) of WI-38 cells—human diploid fibroblasts—can be objectively characterised in the intact cell by flow microfluiorimetry4 and geometric–densitometric texture analysis5. Similar differences in nuclear morphometry and chromatin conformation between proliferating G1 and non-proliferating ‘G0 + Q’ cells are reported here for the first time for tumour cells in vivo, by parallel utilisation of objective image analysis and multiparameter laser flow microfluorimetry, both correlated with autoradiography.