Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ARM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2004

C-arm-based mobile computed tomography: a comparison with established imaging on the basis of simulated treatments of talus neck fractures in a cadaveric study.

OBJECTIVE: To analyse the image quality and diagnostic effectiveness of a new C-arm-based 3D imaging method (C-arm-CT) for intraoperative evaluation of screw osteosyntheses adjacent to a peripheral joint. MATERIALS AND METHODS: Insertion of screws into four cadaveric specimens simulated the surgical treatment of talus neck fractures. Ten orthopedic surgeons and 10 radiologists evaluated X-ray, C-arm fluoroscopy, C-arm-CT and CT images. RESULTS: The best image quality was obtained with X-rays (p < 0.001), followed by C-arm fluoroscopy (2D) and CT, with the C-arm-CT (3D) being rated lowest (p < 0.001). The most correct diagnoses were obtained with CT and C-arm-CT (with no statistical difference between them), while C-arm-fluoroscopy was inferior (p < 0.001) and X-rays were the worst (p < 0.05). CONCLUSIONS: Even if the image quality of C-arm-CT is definitely inferior to that of CT, screw misplacements can be reliably detected using C-arm-CT. As compared to the current standard procedures (intraoperative fluoroscopy and postoperative radiography), C-arm-CT performed better. C-arm-CT is ideally suited to the intraoperative diagnosis of high-contrast inquiries like bone fragments and OS material, especially at the extremities. Coupling of the new 3D imaging to existing navigation systems is possible. C-arm-CT will support the further development and implementation of open and minimally invasive surgical procedures.

Bone Screws↗
PubMed2003

Peak physiologic responses to arm and leg ergometry in male and female patients with airflow obstruction.

STUDY OBJECTIVE: To investigate differences in work capacity for the arms and legs in patients with moderate-to-severe COPD. DESIGN: Cross-sectional investigation. PATIENTS: One hundred twenty-four patients (90 men and 34 women) aged 45 to 81 years with moderate-to-very severe COPD. FEV(1) ranged from 0.70 to 2.79 L/min (FVC, 1.73 to 5.77 L; FEV(1)/FVC, 24 to 69%). All patients were in stable condition at the time of testing and receiving a stable drug regime. MEASUREMENTS: Each patient completed a demographic and medical history questionnaire, pulmonary function studies (spirometry, lung volumes, and diffusion capacity), peak exercise ergometry with gas exchange for the arms and legs; they also rated their subjective assessment of perceived dyspnea and extremity fatigue using Borg scores during exercise. RESULTS: Patients were of comparable age, with men taller and heavier than women. Smoking history was significantly less for women (47.9 pack-years vs 66.6 pack-years for men) even though each group presented with equivalent age (p > 0.05). Women were less obstructed than men, with FEV(1)/FVC (mean +/- SD) of 46.5 +/- 10.9% vs 40.2 +/- 9.3%, respectively. Ventilatory limitation during exercise was noted for all patients studied. Peak work capacity was greater for men, and leg peak responses were greater than arm values for each gender. As airway obstruction increased, work capacity became more limited. Peak arm work achieved was 38.9 +/- 19.6 W, oxygen uptake (VO(2)) was 903.9 +/- 263.5 mL/min, and minute ventilation (VE) was 33.7 +/- 9.5 L. Peak leg work value was 62.9 +/- 24.8 W, VO(2) was 1,091.4 +/- 321.5 mL/min, and VE was 39.3 +/- 12.0 L. Hence, arm values were 62%, 83%, and 85% of the measured leg values, respectively. Dyspnea and extremity effort scores were similar for men and women, and for arms and legs. Regression analysis was used to derive prediction equations for arm work from measured leg ergometry testing. For watts of work, a three-variable model emerged explaining 66% of the variance; VO(2) yielded a four-variable model with 80% of the variance explained; and VE yielded a three-variable model explaining 72% of the variance. CONCLUSION: Arm work is reduced by 38% that of the legs, while more modest reductions are noted for VO(2) and VE, suggesting greater mechanical efficiency for leg work as compared to arm work. These data also suggest greater metabolic demand for respiratory muscles and arm ergometry. Dyspnea and extremity Borg scores were equivalent for each modality and level of airway obstruction studied, suggesting that perception plays an important role in limiting exercise, and that a threshold for termination of exercise may exist. Further, peak leg ergometry results can be used with pulmonary function indexes to predict peak arm workload in watts, VO(2), and VE. These data may be used to assist the clinician in prescribing rehabilitation or estimating arm exercise ability when arm testing is unavailable.

Activities of Daily Living↗
PubMed1994

Comparison of arm up and down in side impacts with BioSID and different armrests.

BioSID dummy tests were run with the arm down at the side during loading of different armrests in simulated side impact crashes. The Hyge sled tests duplicated previous studies of BioSID with the arm up, SID, and animals. When the BioSID arm is against the side, the arm extends from the shoulder to the bottom of the third rib and has a steel shank covered by foam and vinyl. Loading through the arm transfers force to the three chest ribs and shoulder. In comparison, direct armrest loading of the chest or abdomen primarily involves a single rib and substantial rib deflection, when the armrest crush-force exceeds the strength of the rib. The Viscous response in BioSID showed the greatest difference of all criteria for the arm up or down. The response of the third rib correlated with injury risks determined from animal tests using the different armrest designs in a simulated high position. While injury data are not available for the arm at the side or for the armrest in the low position, the STIFF armrest may cause injury when the arm is not at the side and the armrest loads the liver and spleen. Rib deflection in BioSID showed the protrusion of the STIFF armrest into the abdominal region in both arm positions, because the loading was below the arm even in the down position. However, the arm extends laterally so it involves the upper ribs earlier than in the arm-up condition where more space is available.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1995

Hemispace asymmetries and laterality effects in arm positioning.

Hemispace asymmetries and laterality effects were examined on an arm positioning reproduction task. Sixteen male subjects were asked to reproduce both abductive and adductive positioning movements with the left or right arm within either the left or the right hemispace. Hemispace was manipulated using a 90 degrees head-rotation paradigm. A left hemispace advantage in positioning accuracy was predicted for both left and right arm movements on the grounds that the perceptual-motor control of positioning movements made in left hemispace is primarily mediated by the right hemisphere which is known to be advantageous for tasks which are spatial in nature (Heilman, Bowers, & Watson, 1984). No arm laterality effects were predicted to occur because the proximal musculature involved in the control of arm movements is innervated from both contralateral and ipsilateral cerebral hemispheres (Brinkman & Kuypers, 1973). Results showed that the predicted left hemispace advantage was evident for the right arm on the positioning variability measure alone, whereas it was absent for all other possible conditions on all error measures. Laterality (arm) effects were absent as predicted. The experiment also demonstrated a greater degradation of reproduction performance under the "crossed" arm-hemispace conditions than under the "uncrossed" conditions. A plausible explanation for the uncrossed advantage for the task is that under normal conditions, a single hemisphere is primarily responsible for both controlling the contralateral arm and directing attention to the contralateral hemispace, and consequently potential interhemispheric interference is minimized. A clear response bias effect in movement reproduction was also evident as a function of the direction of concurrent arm movement and head rotation. Arm movements made in the same direction as head rotation were systematically undershot in reproduction to a much greater degree than arm movements made in the opposite direction to head rotation.

Adolescent↗
PubMed1990

Is the gender difference in peak VO2 greater for arm than leg exercise?

Based on observations that the difference between men and women in estimates of arm musculature is greater than the difference in leg musculature, it was hypothesized that the gender difference in peak oxygen uptake (VO2; l.min-1) would be greater for arm exercise than leg exercise. To test this hypothesis, 19 (10 men, 9 women) highly trained swimmers (HT) and 20 (10 men, 10 women) untrained students (UT) were tested for peak VO2 on cycle and arm-crank ergometers. Arm and leg fat-free volumes (FFV) were measured to provide an estimate of muscle distribution. No gender difference was observed in either the arm-to-leg peak VO2 ratio (0.699 for the men vs 0.696 for the women) or in the arm-to-leg FFV ratio (0.410 for the men vs 0.402 for the women). Although the proportion of musculature in the arms as assessed by the FFV appeared to be the same in men and women, the similarity in muscle distribution was probably not responsible for the identical average arm-to-leg peak VO2 ratios. The variance in the muscle distribution accounted for only 2-4% of the variance in the arm-to-leg peak VO2 differences within individuals. We conclude that factors other than arm and leg muscle dimensions account for the variability in the arm-to-leg peak VO2 ratio and that the gender difference in peak VO2 is the same for arm and leg exercise.

Adult↗
PubMed1999

Arm position is important for blood pressure measurement.

AIM: To test the effect of positioning the arm on the arm-rest of a common chair, below the officially recommended right atrial level, on the blood pressure (BP) readings in a group of out-patients. PATIENTS AND METHODS: A group of 69 patients (58 hypertensives; 39 males; mean +/- s.d. age 54.1 +/- 16.0 years) participated in the present study. BP and heart rate values obtained in each of the following two positions were compared: (1) sitting with the arms supported on the arm-rests of the chair and (2) sitting with the arms supported at the level of the mid-sternum (the approximation of the right atrial level). BP was measured simultaneously at both arms, with a mercury sphygmomanometer at the right arm and with an automatic oscillometric device at the left arm. RESULTS: Both the systolic and diastolic BPs were significantly higher (P < 0.0001) when the arm was placed on the arm-rest of the chair than at the right atrial level. The same differences +/- s.d. in BP between the two positions were obtained with both measurement techniques: 9.7 +/- 9.4 mm Hg (systolic) and 10.8 +/- 5.8 mm Hg (diastolic) with the mercury sphygmomanometer and respectively 7.3 +/- 8.9 mm Hg and 8.3 +/- 6.0 mm Hg with the oscillometric device. No difference in the heart rate was found between the two positions. CONCLUSIONS: Placing the patient's arms on the arm-rest of the chair instead of at the reference right atrial level, BP measurement will result in spuriously elevated BP values. This may be of great importance for the diagnosis and the subsequent treatment decisions for patients with hypertension.

Adult↗
PubMed1993

Change in macromolecular composition of interstitial fluid from swollen arms after breast cancer treatment, and its implications.

1. The pathophysiology of chronic arm oedema after treatment of breast cancer was investigated by collecting serum and subcutaneous interstitial fluid from the affected and contralateral arms by the wick method (both arms) and by aspiration (oedematous arm). The fluids were analysed for total protein, albumin, glycosaminoglycan and viscosity, and arm volume was measured. 2. Total protein concentration in the aspirated oedema fluid was 32.4 +/- 7.5 g/l (mean +/- SD throughout; n = 39). Protein concentration in wick fluid from the oedematous arm (35.8 +/- 7.3 g/l, n = 14) was not significantly different from that in aspirated fluid. The oedema protein concentrations were significantly lower than in wick fluid from the non-swollen arm (41.4 +/- 6.7 cmH2O, n = 13, P < 0.01, analysis of variance). This was surprising in view of the common assumption that, the condition being of lymphatic origin, the oedema protein concentration should be raised. 3. The ratio of aspirate protein concentration to serum protein concentration showed a weak but highly significant negative correlation with the percentage increase in arm volume (r = -0.47, n = 35, P < 0.005), again in contrast to conventional expectation. The demonstration of a reduced protein concentration in the swollen arm did not therefore depend solely on a comparison with the wick control results. The volume increased by on average 33% and the ratio of aspirate protein concentration to serum protein concentration averaged 0.52 +/- 0.11 on the swollen side and 0.64 +/- 0.13 on the unaffected side. 4. Serum protein concentration in the patients with arm swelling (61.2 +/- 4.9 g/l) was significantly lower than that in postmastectomy patients without this complication (65.0 +/- 6.2 g/l). Most of the decrease occurred in the albumin fraction (oedema patients, 38.3 +/- 5.1 g/l; control patients, 42.0 +/- 2.1 g/l). In oedema patients receiving the anti-oestrogen tamoxifen serum albumin concentration was on average 2.3 g/l lower than in oedema patients not under medication (P < 0.05, t-test). 5. Glycosaminoglycan concentration in oedema fluid was 0.8 +/- 0.14 g/l (n = 21) and 75% was sulphated. Along with the plasma protein this raised the relative viscosity of the fluid to 1.34 +/- 0.16 (n = 11). 6. The reduction in interstitial protein concentration in the swollen arm, contrary to expectation in lymphoedema, could be explained in several ways. One possible hypothesis in light of reported haemodynamic abnormalities in such arms is that capillary pressure rises, increasing capillary filtration rate.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed2006

Comparison of kinematics in skilled and unskilled arms of the same recreational baseball players.

We examined mechanisms of coordination that enable skilled recreational baseball players to make fast overarm throws with their skilled arm and which are absent or rudimentary in their unskilled arm. Arm segment angular kinematics in three dimensions at 1000 Hz were recorded with the search-coil technique from the arms of eight individuals who on one occasion threw with their skilled right arm and on another with their unskilled left arm. Compared with their unskilled arm, the skilled arm had: a larger angular deceleration of the upper arm in space in the forward horizontal direction; a larger shoulder internal rotation velocity at ball release (unskilled arms had a negative velocity); a period of elbow extension deceleration before ball release; and an increase in wrist velocity with an increase in ball speed. It is suggested that some of these differences in arm kinematics occur because of differences between the skilled and unskilled arms in their ability to control interaction torques (the passive torque at one joint due to motion at adjacent joints). It is proposed that one reason unskilled individuals cannot throw fast is that, unlike their skilled counterparts, they have not developed the coordination mechanisms to effectively exploit interaction torques.

Acceleration↗
PubMed2002

Age-dependent variations in the directional sensitivity of balance corrections and compensatory arm movements in man.

We investigated the effects of ageing on balance corrections induced by sudden stance perturbations in different directions. Effects were examined in biomechanical and electromyographic (EMG) recordings from a total of 36 healthy subjects divided equally into three age groups (20-34, 35-55 and 60-75 years old). Perturbations consisted of six combinations of support-surface roll (laterally) and pitch (forward-backward) each with 7.5 deg amplitude (2 pure pitch, and 4 roll and pitch) delivered randomly. To reduce stimulus predictability further and to investigate scaling effects, perturbations were at either 30 or 60 deg s(-1). In the legs, trunk and arms we observed age-related changes in balance corrections. The changes that appeared in the lower leg responses included smaller stretch reflexes in soleus and larger reflexes in tibialis anterior of the elderly compared with the young. For all perturbation directions, onsets of balance correcting responses in these ankle muscles were delayed by 20-30 ms and initially had smaller amplitudes (between 120-220 ms) in the elderly. This reduced early activity was compensated by increased lower leg activity after 240 ms. These EMG changes were paralleled by comparable differences in ankle torque responses, which were initially (after 160 ms) smaller in the elderly, but subsequently greater (after 280 ms). Findings in the middle-aged group were generally intermediate between the young and the elderly groups. Comparable results were obtained for the two different stimulus velocities. Stimulus-induced trunk roll, but not trunk pitch, changed dramatically with increasing age. Young subjects responded with early large roll movements of the trunk in the opposite direction to platform roll. A similarly directed but reduced amplitude of trunk roll was observed in the middle-aged. The elderly had very little initial roll modulation and also had smaller stretch reflexes in paraspinals. Balance-correcting responses (over 120-220 ms) in gluteus medius and paraspinals were equally well tuned to roll in the elderly, as in the young, but were reduced in amplitude. Onset latencies were delayed with age in gluteus medius muscles. Following the onset of trunk and hip balance corrections, trunk roll was in the same direction as support-surface motion for all age groups and resulted in overall trunk roll towards the fall side in the elderly, but not in the young. Protective arm movements also changed with age. Initial arm roll movements were largest in the young, smaller in the middle aged, and smallest in the elderly. Initial arm roll movements were in the same direction as initial trunk motion in the young and middle aged. Thus initial roll arm movements in the elderly were directed oppositely to those in the young. Initial pitch motion of the arms was similar across age groups. Subsequent arm movements were related to the amplitude of deltoid muscle responses which commenced at 100 ms in the young and 20-30 ms later in the elderly. These deltoid muscle responses preceded additional arm roll motion which left the arms directed 'downhill' (in the direction of the fall) in the elderly, but 'uphill' (to counterbalance motion of the pelvis) in the young. We conclude that increased trunk roll stiffness is a key biomechanical change with age. This interferes with early compensatory trunk movements and leads to trunk displacements in the direction of the impending fall. The reversal of protective arm movements in the elderly may reflect an adaptive strategy to cushion the fall. The uniform delay and amplitude reduction of balance-correcting responses across many segments (legs, hips and arms) suggests a neurally based alteration in processing times and response modulation with age. Interestingly, the elderly compensated for these 'early abnormalities' with enlarged later responses in the legs, but no similar adaptation was noted in the arms and trunk. These changes with age provide an insight into possible mechanisms underlying falls in the elderly.

Adult↗
PubMed2006

Regional differences in glucose clearance: effects of insulin and resistance training on arm and leg glucose clearance in older hypertensive individuals.

The purpose of this study was to compare insulin's ability to stimulate glucose uptake in the arm and leg in a group of older hypertensive individuals (n = 13, 66 +/- 2 yr old). We also examined the effect of a 4-mo whole body resistance-training (RT) program on arm and leg glucose clearance (GC) during a hyperinsulinemic-euglycemic clamp. During the hyperinsulinemic-euglycemic clamp, GC was assessed by simultaneous measurement of arm and leg blood flow (BF) and assessment of fractional glucose extraction (GE) in blood samples from the brachial artery, brachial vein, and popliteal vein. At baseline, a significant main effect (arm vs. leg) demonstrated greater GC and BF in the arm than in the leg (P = 0.006 for GC and P = 0.012 for BF). Insulin significantly increased GE, BF, and GC in the arm and leg (main effects: P = 0.0001 for GE, P = 0.0001 for BF, and P = 0.0001 for GC) at baseline. However, the effect of insulin was similar in the arm and leg. After RT, a significant main effect (baseline vs. RT) demonstrated greater GE and GC in the leg (P = 0.024 for GE and P = 0.053 for GE), but not in the arm (P = 0.31 for GE and P = 0.14 for GC). No significant main effect (baseline vs. RT) for BF in the arm or leg was observed after RT. In conclusion, the greater GC in the arm than in the leg at baseline is primarily due to enhanced arm BF. Furthermore, whole body RT appears to increase GC in the leg but not in the arm.

Aged↗
PubMed1993

The ventilatory response to arm elevation of patients with chronic obstructive pulmonary disease.

Although arm activity is poorly tolerated by patients with COPD, the ventilatory response to arm elevation alone is not well understood. We therefore studied the ventilatory response to arm elevation using a customized arm support sling to eliminate the effect of an increase in metabolic activity that might be attributable to independent arm elevation and used leg exercise to increase metabolic activity. During arm elevation at rest, there was a significant decrease in vital capacity (180 ml) and a small decrease in functional residual capacity (120 ml) as measured by body plethysmography. Minute ventilation was unchanged. When supported arm elevation (SAE) was compared with the control arm position (CAP), minute ventilation was unchanged although the pattern of breathing became more rapid and shallow (mean +/- SD, SAE vs CAP: fb = 17.9 +/- 5.3 vs 16.2 +/- 4.8 breaths.min-1; VT = 533 +/- 126 vs 579 +/- 142 ml; p < 0.05). During steady-state leg exercise, the increase in VO2, VCO2 and VE did not differ between SAE and CAP; however, both fb and VT changed toward a more rapid, shallow pattern of breathing (SAE vs CAP: fb = 24.3 +/- 3.0 vs 22.8 +/- 3.5 breaths.min-1; VT = 990 +/- 293 vs 1,081 +/- 309 ml; p < 0.05). During unsupported arm elevation VO2, VCO2, and VE, and fb were significantly greater than during the CAP. Approaches that train arm muscles and strategies that either support arm muscles or allow for frequent rests during upper arm activity may improve the endurance and the quality of life for COPD patients.

Aged↗
PubMed2000

A comparison of brachial artery flow-mediated vasodilation using upper and lower arm arterial occlusion in subjects with and without coronary risk factors.

BACKGROUND: The ultrasound assessment of brachial artery flow-mediated vasodilation provides a noninvasive means for measuring endothelial function. The test is performed using either upper or lower arm blood pressure cuff arterial occlusion to induce hyperemia. Upper arm occlusion produces a greater hyperemic stimulus. Brachial artery flow-mediated vasodilation is abnormal in the presence of coronary risk factors. HYPOTHESIS: The study sought to compare the ability of the upper and lower arm occlusion techniques to differentiate endothelial function in subjects with and without risk factors. METHODS: We measured brachial artery flow-mediated vasodilation in 20 subjects, 10 without and 10 with a single risk factor (hypertension, hypercholesterolemia, or cigarette smoking) using both the upper and lower arm occlusion techniques (5 min blood pressure cuff occlusion). Using 11 MHz ultrasound, Doppler blood flow velocities were measured before and immediately after cuff deflation. Brachial artery vasodilation was measured 1 min after cuff deflation, compared with baseline, and expressed as a percent increase. RESULTS: The immediately postocclusion hyperemia (% increase in flow) was significantly greater (p < 0.01) using the upper versus the lower arm technique in both the normal (530 +/- 152 vs. 383 +/- 51%) and the risk factor (583 +/- 153 vs. 409 +/- 114%) groups. Flow-mediated vasodilation was significantly greater (p < 0.01) using the upper arm versus the lower arm occlusion technique in both the normal (13.4 +/- 5.3 vs. 5.6 +/- 3.4%) and risk factor (7.9 +/- 3.6 vs. 3.9 +/- 2.2%) groups. Vasodilation was significantly greater (p < 0.01) in the normal subjects than in the risk factor subjects (13.4 +/- 5.3 vs. 7.9 +/- 3.6%) using the upper arm technique, but was not statistically different in the two groups using the lower arm technique. CONCLUSIONS: Our study demonstrates that upper arm compared with lower arm cuff occlusion undertaken to induce hyperemia for the assessment of brachial artery flow-mediated vasodilation results in significantly greater hyperemia and vasodilation. Flow-mediated vasodilation obtained using the upper arm technique better separates subjects with and without coronary risk factors.

Adult↗
PubMed1988

Dynein as a microtubule translocator in ciliary motility: current studies of arm structure and activity pattern.

The dynein arms of ciliary doublet microtubules cause adjacent axonemal doublets to slide apart with fixed polarity. This suggests that there is a unique mechanochemistry to the dynein arm with unidirectional force generation in all active arms and also that not all arms are active at once during a ciliary beat. Negative stain and thin-section images of arms in axonemes treated with beta, gamma methylene adenosine triphosphate (AMP-PCP) show a consistent subunit construction where the globular head of the arm interacts with subfiber B of doublet N+1. This interpretation differs from that provided by freeze etch and STEM interpretations of in situ arm construction and has implications for the mechanochemical cycle of the arm. A computer model of the arms in relation to other axonemal structures has been constructed to test these interpretations. Attachment of the head of the arm subfiber B is directly demonstrable in splayed axonemes in AMP-PCP. About half of the doublets in an axoneme show such attachments, while half do not. This might imply that about half the doublets in an axoneme are active at any given instant and can be identified as such. This information may be useful in probing questions of how active arms differ biochemically from inactive arms and of how microtubule translocators in general become active.

Adenosine Triphosphatases↗
PubMed1989

The role of the hippocampal-nucleus accumbens pathway in radial-arm maze performance.

The role of the glutamatergic hippocampal-nucleus accumbens pathway in relaying hippocampal information via the nucleus accumbens to the motor system was investigated behaviorally using the radial-arm maze paradigm in rats. Bilateral injections of kynurenic acid, a glutamate antagonist, into the nucleus accumbens increased the latency to initiate movement during performance of an 8-arm radial maze with all arms baited and with 4 arms baited. Injections of kynurenic acid did not change the number of visits to previously visited arms (i.e. working memory errors) on both versions of the 8-arm radial maze. However, on the 8-arm radial maze with 4 arms baited, injections increased the number of visits to unbaited arms (i.e. reference memory errors). Similar injections were made in rats with ibotenic acid lesions of the prefrontal cortex in order to eliminate the glutamatergic prefrontal cortex-nucleus accumbens pathway so as to investigate the glutamatergic hippocampal-nucleus accumbens pathway. These rats displayed similar deficits on the radial-arm maze as non-lesioned rats (i.e. enhanced latency to initiate movement and reference memory errors). These findings suggest that the glutamatergic hippocampal-accumbens pathway plays a role in radial-arm maze performance by transferring information required for performing a radial-arm maze to the motor system.

Animals↗
PubMed2001

A three-arm phase III randomised trial assessing, in patients with extensive-disease small-cell lung cancer, accelerated chemotherapy with support of haematological growth factor or oral antibiotics.

The European Lung Cancer Working Party (ELCWP) designed a 3-arm phase III randomised trial to determine the role of accelerated chemotherapy in extensive-disease (ED) small-cell lung cancer (SCLC). Eligible patients were randomised between the 3 following arms: (A) Standard chemotherapy with 6 courses of EVI (epirubicin 60 mg m(-2), vindesine 3 mg m(-2), ifosfamide 5 g m(-2); all drugs given on day 1 repeated every three weeks. (B) Accelerated chemotherapy with EVI administered every 2 weeks and GM-CSF support. (C) Accelerated chemotherapy with EVI and oral antibiotics (cotrimoxazole). Primary endpoint was survival. 233 eligible patients were randomised. Chemotherapy could be significantly accelerated in arm B with increased absolute dose-intensity. Best response rates, in the population of evaluable patients, were, respectively for arm A, B and C, 59%, 76% and 70%. The response rate was significantly higher in arm B in comparison to arm A (P = 0.04). There was, however, no survival difference with respective median duration and 2-year rate of 286 days and 5% for arm A, 264 days and 6% for arm B and 264 days and 6% for arm C. Severe thrombopenia occurred more frequently in arm B but without an increased rate of bleeding. Non-severe infections were more frequent in arm B and severe infections were less frequent in arm C. Our trial failed to demonstrate, in ED-SCLC, a survival benefit of chemotherapy acceleration by using GM-CSF support.

Administration, Oral↗
PubMed1982

Immunological dissimilarity in protein component (dynein 1) between outer and inner arms within sea urchin sperm axonemes.

The 0.5 M KCl-treatment solubilizes the outer arms from sea urchin sperm axonemes. Approximately 30 percent of A-polypeptide, corresponding to dynein 1 in SDS- polyacrylamide gel, was solubilized by this treatment (as SEA-dynein 1). Electron microscopic observation indicated that the extracted axonemes lacked the outer arms in various degrees. The DEA-dynein 1 was that the extracted axonemes lacked the outer arms in various degrees. The SEA-dyenin 1 was purified and an antiserum against it was prepared in rabbits. The specificity of antiserum to dynein 1 was determined by immunoelectrophoresis and ouchterlony's double-diffusion test. The anti-dynein 1 serum inhibited ATPase activity of purified SEA-dynein 1 by 95 percent. By the indirect peroxidase-conjugated antibody method, the loci of SEA-dynein 1 within the intact, salt- extracted and mechanically disrupted axonemes were determined to be the outer arms: deposition of electron-dense materials which represents their localization was detected at the distal ends of the outer arms, in the case of intact axonemes. The 5-6 cross- bridge was hardly decorated. No decoration was seen in the salt-extracted axonemes lacking all the outer arms. In disrupted axonemes, which consist of single to several peripheral doublets, electron-dense materials were deposited only on the outer arms. Approximately 73 percent of axonemal ATPase activity sensitive to antiserum was solubilized by repeated salt-extractions. One-half of A-polypeptide (SEA-dynein 1 located at the outer arms) was contained in the pooled extracts. The extracted axonemes contained another half of A-polypeptide (SUA-dynein 1 supposed to locate at the inner arms) and retained 31 percent of axonemal ATPase activity that was almost resistant to antiserum. Solubilized SUA-dynein 1 was immunologically the same as SEA-dynein 1. This result indicates that in situ SUA-dynein 1 did not receive anti-dynein 1 antibodies, coinciding with the result obtained for salt-extracted axonemes lacking all the outer arms by the enzyme-antibody method mentioned above. These observations suggest that immunological dissimilarity in dynein 1 between outer and inner arms but do not tell us that the inner arms do not contain dynein 1.

Adenosine Triphosphatases↗
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↗
PubMed2006

Specific interactions by the N-terminal arm inhibit self-association of the AraC dimerization domain.

Deletion of the regulatory N-terminal arms of the AraC protein from its dimerization domain fragments increases the susceptibility of the dimerization domain to form a series of higher order polymers by indefinite self-association. We investigated how the normal presence of the arm inhibits this self-association. One possibility is that arms can act as an entropic bristles to interfere with the approach of other macromolecules, thereby decreasing collision frequencies. We examined the repulsive effect of flexible arms by measuring the rate of trypsin cleavage of a specially constructed ubiquitin-arm protein. Adding an arm to ubiquitin or increasing its length produced only a modest repulsive effect. This suggests that arms such as the N-terminal arm of AraC do not reduce self-association by entropic exclusion. We consequently tested the hypothesis that the arm on AraC reduces self-association by binding to the core of the dimerization domain even in the absence of arabinose. The behaviors of dimerization domain mutants containing deletions or alterations in the N-terminal arms substantiate this hypothesis. Apparently, interactions between the N-terminal arm and the dimerization domain core position the arm to interfere with the protein-protein contacts necessary for self-association.

AraC Transcription Factor↗