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At least 19 recordsLinked to original sources
PubMed1976

Spontaneous alternation of the working arm in one-arm cranking.

One-arm cranking was done by ten healthy male adults at an oxygen intake level of about 1.0 liter/min. Each subject performed two kinds of cranking at a speed of 60 rpm: forced cranking using only one arm continuously for 15 min and free cranking for 30 min with the instructions to alternate from one arm to the other whenever fatigue set in. The results, excluding those of a subject who changed arms very frequently, were analyzed. In forced cranking, oxygen intake and heart rate steadily increased, the average time of appearance of local fatigue being 161 sec for the stronger arm and 122 sec for the weaker one. In free cranking, the working arm was changed 6 to 23 times during the 30-minute period, while oxygen intake and heart rate increased with fluctuations. The mean duration interval was 175 sec with the stronger arm and 123 sec with the weaker one. The mean interval of arm alternation was positively correlated with the individual time of onset of the sensation of local rigidness during forced cranking, but not with the individual time of initiation of respiratory distress. It is suggested that alternation of active muscles in moderately dynamic work may be linked with an early stage of local fatigue which is different from that of static work.

Adult↗
PubMed1975

The influence of arm ischaemia and arm hyperaemia on subclavian and vertebral artery blood flow in patients with occlusive disease of the subclavian artery and the brachiocephalic trunk. A peroperative study.

A peroperative study of blood flow and flow direction was performed in series of patients with occlusive disease of the subclavian artery. Particular attention was focused on the flow variations caused by arm ischaemia and postischaemic hyperaemia and on the effect of injection of a vasodilator into the distal subclavian artery. The effect on blood flow and flow direction was measured with the aid of an electromagnetic flowmeter. During arm ischaemia induced by an inflated cuff on the arm, the subclavian flow diminished, as did the vertebral artery flow when it was retrograde. If the vertebral artery flow was anterograde, it increased during arm ischaemia. The postischaemic hyperaemia caused an increase of the subclavian flow and of reversed vertebral flow. If the vertebral flow was anterograde, it diminished during the postischaemic hyperaemia. Similar findings were obtained with intra-arterial injection of a vasodilator. The large amount of blood flow passing through the vertebral artery, as well as the flow variations caused by reactive arm hyperaemia, emphasize the role of this artery as a collateral vessel to the upper limb in cases of the subclavian steal phenomenon.

Adult↗
PubMed1977

X chromosomes attached by their long arm: replication autonomy of the short arm adjacent to the inactive centromere.

A 16 years old girl with Turner syndrome was found to have a 45,X/46,X,t(XqXq)?(q27q23) constitution. The two X chromosomes are attached by their long arms with loss of chromosome material and have one active and one inactive centromere. Analysis of replication patterns with autoradiography and BrdU treatment showed that the abnormal X is always the late replicating one and that the short arm of the second X which is adjacent to the inactive centromere maintains a degree of replication autonomy from the rest of the long arm.

Adolescent↗
PubMed1975

A patient with congenital anomalies and a deletion of the long arm of the long arm of chromosome 4 [46,XY,del(4)(q31)].

This paper describes the clinical symptoms and cytogenetic findings in a patient previously described in a doctoral thesis (van Kempen, 1969). The patient is a boy with multiple congenital anomalies and a deletion of the long arm of chromosome 4. A recent Giemsa banding study showed absence of the terminal G-band, as was found in the patient described by Golbus et al (1973). The symptoms and other data on the three patients known to have a deletion of the long arm of chromosome 4 are presented to facillitate comparison of these cases. However, the number of cases so far on record is too small to warrant conclusions on the basis of this comparison.

Abnormalities, Multiple↗
PubMed1978

Complex arming in antibody-dependent cell-mediated cytotoxicity: ultrastructural studies of the interaction between human effector cells armed with aggregated anti-DNP antibody and DNP-coated erythrocytes.

We have examined, by transmission electron microscopy, mixtures of DNP-coated chicken red blood cells and normal human peripheral blood leucocytes 'armed' with alkali-aggregated anti-dinitrophenyl (DNP) antibody. The combination of these observations with chromium release assays enabled us to identify four types of effector cell interacting with the target erythrocytes, viz. phagocytic and non-phagocytic monocytes, neutrophils and lymphocytes. Comparison of these findings with previous work, using antibody-coated targets, allowed us to conclude that the mechanisms and cell types involved are similar. We also demonstrated the short-lived cytotoxic potential of cells armed in this manner.

Antibodies↗
PubMed1976

Activity of ventrolateral thalamic neurons during arm movement.

1. Monkeys were trained to maintain the handle of a manipulation within a small zone despite perturbations to the handle and to perform slow and rapid arm movements triggered by a visual stimulus. The activity of neurons in the region of the ventrolateral thalamus which projects directly to the arm area of the motor cortex (VL arm area) was then examined during performance of the task and while the animal's limb was passively manipulated. 2. Thalamic units related to arm movement were confined to the VL arm area. Microstimulation (less than 25 muA) in the VL arm area could, in some instances, evoke localized contractions of shoulder, arm, and hand musculature. Thalamic units whose discharge appeared to be related to jaw, tongue, and neck muscle activity occurred only medial to arm movement-related units, and units related to spontaneous leg movements occurred only laterally. 3. Most VL arm area neurons, although well related to active arm movements, were not influenced by gentle passive manipulation of the animal's limb. Few VL arm area neurons responded at short latency to perturbations applied to the handle of the manipulandum which the animal was holding. Thus, VL arm area neurons are unlike many motor cortex arm area neurons which are responsive to passive manipulation and are influenced at short latency by similar perturbations to the animal's limb. 4. Most arm movement-related VL neurons discharge during both fast and slow arm movements. Although a few neurons varied their discharge only during fast movements, none varied only in relation to slow movements. VL arm area neurons are, therefore, unlike the neurons in one source of its input, the globus pallidus, where some neurons are preferentially related to slow movements. 5. Some VL arm area neurons vary their discharge before any change in muscle activity during a fast and slow movement. Such neurons were recorded in VL regions which project to motor cortex areas representing proximal and distal musculature. This suggests that VL neurons might play a role in initiating activity in muscles concerned with controlling body posture, as well as those involved in discrete limb movements.20

Animals↗
PubMed1979

Arms races between and within species.

An adaptation in one lineage (e.g. predators) may change the selection pressure on another lineage (e.g. prey), giving rise to a counter-adaptation. If this occurs reciprocally, an unstable runaway escalation or 'arms race' may result. We discuss various factors which might give one side an advantage in an arms race. For example, a lineage under strong selection may out-evolve a weakly selected one (' the life-dinner principle'). We then classify arms races in two independent ways. They may be symmetric or asymmetric, and they may be interspecific or intraspecific. Our example of an asymmetric interspecific arms race is that between brood parasites and their hosts. The arms race concept may help to reduce the mystery of why cuckoo hosts are so good at detecting cuckoo eggs, but so bad at detecting cuckoo nestlings. The evolutionary contest between queen and worker ants over relative parental investment is a good example of an intraspecific asymmetric arms race. Such cases raise special problems because the participants share the same gene pool. Interspecific symmetric arms races are unlikely to be important, because competitors tend to diverge rather than escalate competitive adaptations. Intraspecific symmetric arms races, exemplified by adaptations for male-male competition, may underlie Cope's Rule and even the extinction of lineages. Finally we consider ways in which arms races can end. One lineage may drive the other to extinction; one may reach an optimum, thereby preventing the other from doing so; a particularly interesting possibility, exemplified by flower-bee coevolution, is that both sides may reach a mutual local optimum; lastly, arms races may have no stable and but may cycle continuously. We do not wish necessarily to suggest that all, or even most, evolutionary change results from arms races, but we do suggest that the arms race concept may help to resolve three long-standing questions in evolutionary theory.

Adaptation, Biological↗
PubMed1976

[Coordination of arm movement during locomotion in Ophiuroidea].

Ophiura Amphipholis kochii Lütken can move with any one of five arms directed forwards; therefore, each arm performs various functions during locomotion. The arm amputated together with the adjoining part of the central nervous ring is capable of complicated behaviour, particularly, of locomotion. Transection of the central nervous ring results in disturbances of the arms coordination. Experiments with amputation of a part of the arms showed that afferent signals from arms are important for determination of the leading arm and mode of locomotion. The experimental data suggest that each arm has an autonomous nervous centre, and coordinated activity of all arms is acheaved by an interaction of the nervous centres. The interaction results in function distribution among the arms and in synchronization of arm movements. The leading arm prevails, since the influences exerting by its centre determine activity of adjacent centres.

Animals↗
PubMed1979

An evaluation of upper arm measurements used in nutritional assessment.

Triceps skinfold thickness and upper arm circumference (parameters used in assessing protein-calorie malnutrition) were measured on both arms of 91 adult volunteers who fulfilled criteria for absence of disease and conditions affecting nutritional status. For the total study group and subgroups of men only and women only, no significant differences were noted between right and left arm measurements of triceps skinfold thickness, arm circumference, or arm muscle circumference. Median values for significant right-left arm measurement differences were + 1.7 mm for the triceps skinfold thickness of left-handed subjects (P less than 0.05) and + 0.3 cm for the arm circumference of volunteers regularly engaged in predominately right-armed activities (P less than 0.05). Criteria of weight within 15% of "ideal" and nine serum and plasma values within a specified range were fulfilled by 77 subjects, and they comprised the "healthy" subgroup. Left arm median values for healthy men and healthy women differed from a currently accepted standard for each of three anthropometric parameters: triceps skinfold thickness (P less than 0.05), arm circumference (P less than 0.05), and arm muscle circumference (P less than 0.01).

Adult↗
PubMed1977

Oxygen uptake transients at the onset and offset of arm and leg work.

The halftimes (t1/2) of the VO2 on-and off-responses have been determined on 4 moderately active subjects (1) in arm cranking (VO2 congruent to 1 1/min). (2) in leg pedaling at 4 graded submaximal (VO2 congruent to 0.8 to 2.51/min) work loads, and (3) when superimposing arm cranking on preexisting leg pedaling, both in the supine and in the upright position. In supine experiments the mean t1/2 of the VO2 on-response was longer for arm cranking than for leg pedaling (64 vs 44-49 sec) at equal VO2; however, at the same percentage of arm and leg VO2 max the respective t1/2 were similar. In sitting experiments all t1/2 of the VO2 on-response were shorter than when supine, but the t1/2 for the arms were still slightly longer than those for the legs. When arm cranking was superimposed on preexisting leg pedaling, the t1/4 for arms was reduced both in supine (from 64 to 35-38 sec) and in the sitting position (from 44 to 40 sec). The halftime of the VO2 off-response were much shorter (20-32 sec) than those of the on-response and similar in all experiments. In all conditions the O2 deficits at work onset were considerably larger than the fast component of the corresponding O2 debts during the first minutes of recovery. The difference was totally accounted for by anaerobic glycolysis occurring early during the VO2 on-response, particularly in arm exercise. It is concluded that at submaximal work loads the O2 deficit is accounted for the fast component of the O2 debt plus the O2 equivalent of the early lactate production.

Adult↗
PubMed1977

A comparison of the response to arm and leg work in patients with ischemic heart disease.

An exercise test based on arm work was evaluated in a series of 33 male patients, mean age 52 years, with ischemic heart disease. The responses to arm exercise on a modified table-mounted bicycle ergometer and to standard bicycle exercise were compared. Twenty six of 33 patients (79 per cent) had identical end-points with both tests. Three patients had an ischemic response, i.e., significant ST abnormality and/or angina pectoris during leg work only, and four patients during arm work only. 41 per cent of the peakload during leg exercise. Mean values were 181 and 439 kpm./min. (p less than 0.001). Comparison of individual data on peak load demonstrated only a weak correlation between arm and leg work capacity (r = 0.37, p less than 0.05). Peak heart rate was slightly higher during leg work, 129 compared to 122 beats/min. (p less than 0.05) but the mean heart rate-systolic blood pressure products were not significantly different. A subgroup of seven patients had a history of angina pectoris preferentially precipitated by arm work but their physiological responses did not differ significantly from those of patients without a history of arm work sensitivity. The data indicate that arm work is a satisfactory alternate diagnostic test method with respect to myocardial ischemia, but measurements of physical work capacity defined as aerobic capacity, cannot be based on arm work.

Adult↗
PubMed1976

Upper arm anthropometric indicators of nutritional status.

The growth in arm muscle area and arm fat area of preschool children from rural Guatemala is compared to that of a standard from the U.S.A. It was found that although the Guatemalan children have reduced arm muscle and fat areas, the relative reduction in arm fat area was greater than in arm muscle area. Further, the upper arm cross-sectional area of Guatemalan children had proportionately more muscle than fat when compared to that of U.S.A. children. Lastly, for the same body weight, Guatemalan children had a similar arm muscle area but a clearly smaller arm fat area than North American children. It is concluded that these findings suggest that energy rather than protein is the main nutritional problem in these Guatemalan children.

Age Factors↗
PubMed1976

Maximal oxygen uptake during exercise with various combinations of arm and leg work.

Oxygen uptake (VO2) was determined in 10 males during the following types of maximal exercise (work time: about 5 min): uphill running, bicycling, arm work (cranking), and combined arm work and bicycling (A + L). The A + L exercise was performed in four different ways, the arms doing 10%, 20%, 30%, or 40% of the same total rate of work; and also with the maximal bicycle work load plus either maximal or submaximal arm work. VO2 was the same in running as in all types of A + L exercise, except when the arm work load was 10% and 40% of the total rate of work, where VO2 was 2.5% (P less than 0.05) and 9.4% (P less than 0.001) lower, respectively. Bicycle VO2 was lower than VO2 in running but equal to A + L VO2 when arm work intensity was 40% of the total rate of work. It is concluded that VO2 during maximal exercise a) to a certain extent depends on the exercising muscle mass, b) is lower than the oxygen-consuming potential of the muscles involved in A + L exercise, and c) in A + L exercise is influenced by the ratio of arm work to total rate of work and the subject's fitness for arm work and bicycling.

Adult↗
PubMed1979

Characteristics of motor programs underlying arm movements in monkeys.

1. The experiments described here are addressed at identifying some of the processes underlying arm movements in monkeys. 2. We used three adult monkeys that were trained to point to a target light with the forearm and hold at that position for about 1 s in order to obtain a reward. During the experimental sessions the monkey was seated in a primate chair and its forearm was fastened to an apparatus that permitted flexion and extension of the forearm about the elbow in the horizontal plane. 3. We tested their performance prior to and after bilateral dorsal rhizotomy (C2--T3). Forearm movements were performed without the sight of the arm both before and after the surgical intervention. In intact animals we unexpectedly displaced the arm prior to movement initiation (150--200 ms) and observed the outcome of this displacement on movement termination. Our results indicated that the arm moved accurately to the target. The same procedure was used in the deafferented monkeys, yielding qualitatively the same results; i.e., a displacement of the initial position did not affect the attainment of the intended final position. 4. These results are relevant to the question of what is being controlled by motor commands. It appears that the controlled variable is an equilibrium point resulting from the interaction of agonist and antagonist muscles. Consequently, a change in the equilibrium leads to movement and the attainment of a new posture. The fact that both intact and deafferent monkeys display essentially similar motor behavior in our highly practiced task should not obliterate the dramatic difference in motor performance that exists between intact and rhizotomized animals. In fact, the successful execution of the learned motor performance in the deafferented animal is contingent on the animal's body being in a fixed relation to the arm apparatus. Whenever we changed the usual spatial relationship between the monkey's body and the arm apparatus, the animal's pointing response to the target was inaccurate. All of our intact monkeys, in contrast, were able to compensate quickly for any variations in their accustomed position with respect to the arm apparatus. The dramatic inability of the deafferented monkey to execute accurate pointing responses in an unusual postural setting underscores the great importance of the afferent monkey to execute accurate pointing responses in an unusual postural settiing underscores the great importance of the afferent feedback. These findings suggest that, in the performance of visually evoked learned movements, one of the major functions of the afferent feedback is in the adaptive modifications of learned motor programs.

Afferent Pathways↗
PubMed1976

Transmission of vibration in the hand-arm system with special reference to changes in compression force and acceleration.

The transmission of longitudinal vibration in the hand-arm system of five subjects was investigated. Altogether 405 individual tests were made. Vibration was measured with an accelerometer (weight 0.4 g) fixed in turn to the wrist, the elbow, and the upper arm by means of a supporting device (weight 34 g). A handle with strain gauges attached was used to study the effect of compression force (10, 20 and 40 N) and constant acceleration (1, 3 and 10 g) on the transmission of vibration at frequencies from 20 to 630 Hz. In the curves recorded, sharp dips appeared which were evidently caused by resonances from the soft tissues of the hand. However in the hand-arm system no common resonance frequency was observed that would harmfully affect the health of workers. Vibration in the hand-arm system was attenuated at an average of 3 dB per octave at the frequencies between 20 and 100 Hz. Between 100 and 630 Hz the attenuation was about 6 dB per octave in the wrist and 10 dB per octave in the elbow and upper arm. At the frequency of 630 Hz the attenuation was hence about 35 dB in the wrist and about 45 DB in the elbow. The attenuation of vibration in the elbow joint was 2 to 4 dB at all frequencies. The hand-arm system appears to be linear at the acceleration range considered; the increase in handle vibration by, e.g., 10 dB also increased vibration in the hand by 10 dB. When the grip strength was increased fourfold, i.e., 12 dB, vibration increased only 3 to 5 dB in the hand-arm system. Thus changing the weight of a vibrating tool does not reduce vibration enough. Therefore attempts to reduce vibration should concentrate on the mechanical parts of the engines.

Acceleration↗