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[Biomechanical study on orthodontic tooth movement: changes in biomechanical property of the periodontal tissue in terms of tooth mobility].

The magnitude of tooth mobility has been frequently used for evaluating biomechanical response of the periodontal tissue to applied forces. However, tooth mobility during orthodontic tooth movement has not been measured. The purpose of this study was to investigate changes in biomechanical property of the periodontal tissue during canine retraction, in terms of tooth mobility. The upper canines on both sides of ten orthodontic patients were moved in the distal direction for about four weeks with an initial force of 200 gf. An amount of tooth movement and a magnitude of tooth mobility were measured every 3 or 4 days during retraction. A distally directed force up to 500 gf was continuously applied to each canine and tooth mobility was measured with a noncontact type of eddy current displacement sensor. A two-dimensional finite element model was constructed and displacements of the finite element model were calculated with various Young's moduli in loading with a 100 gf force in the distal direction. In comparison with the magnitudes of the tooth mobility, Young's modulus of the periodontal membrane before retraction and the influence of the biomechanical factors on changes in tooth mobility were investigated. The tooth movement curve was divided into three phases; an initial phase, a lag phase and a post-lag phase. The magnitudes of tooth mobility at the initial phase were significantly larger than those before retraction within the range of 250 gf to 500 gf and these magnitudes decreased during the lag phase. The magnitudes of tooth mobility at the post-lag phase significantly increased, within the range of 50 gf to 500 gf, than those before retraction. As a result of curveliniar regression analysis, the tooth mobility curves approximated to delta = AFB, where delta and F denote tooth mobility and force respectively. The coefficients A and B changed according to the phases of tooth movement. An inclination of the tooth mobility curve expressed by a tangent at the 400 gf force was the largest at the initial phase, and this inclination at the 100 gf force was the largest at the post-lag phase. Young's modulus of the periodontal membrane before retraction was determined to be approximately 35 gf/mm2 and Young's modulus of the periodontal membrane was the most important factor on the increase of tooth mobility. Tooth mobility significantly varied associated with tooth movement. It was indicated that biomechanical property of the periodontal tissue changes in response to each phase of tooth movement. In particular, Young's modulus of the periodontal membrane decreased at the post-lag phase of the orthodontic tooth movement.

Cuspid↗

Mobility status during inpatient rehabilitation: a comparison of patients with stroke and traumatic brain injury.

OBJECTIVES: To compare the mobility status (admission and discharge status, change in status) between patients with stroke and traumatic brain injury (TBI) during inpatient rehabilitation and to determine the relationship between mobility status and outcome variables including length of stay (LOS). DESIGN: Prospective study. SETTING: Free-standing tertiary rehabilitation center. PARTICIPANTS: A total of 210 patients with stroke (n = 136) and TBI (n = 74) consecutively admitted for inpatient rehabilitation. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Clinical Outcome Variable Scale (COVS), a 13-item scale of mobility status (measured on admission and discharge from inpatient rehabilitation), and rehabilitation LOS. RESULTS: With age and time since injury controlled in the model, the TBI group showed a significantly higher mobility status on admission and discharge over the stroke group, but the change (improvement) in mobility status did not differ. The admission mobility status accounted for 61% and 60% of variability of the discharge mobility status for the stroke and TBI groups, respectively. The admission mobility status accounted for 40% and 50% of the variability in rehabilitation LOS for the stroke and TBI groups, respectively. Either the admission mobility status or the physical therapist's prediction of the discharge status could be used to determine the actual discharge mobility status, although the physical therapist's predictions were more accurate than using a statistical model. CONCLUSIONS: The TBI group showed a higher mobility status at admission and discharge from inpatient rehabilitation than the stroke group; however, the rate of improvement (improvement in mobility status per day) did not differ between groups. Admission mobility status using the COVS was an excellent predictor of discharge mobility status and rehabilitation LOS in stroke and TBI patients.

Activities of Daily Living↗

Lateral mobility of band 3 in the human erythrocyte membrane studied by fluorescence photobleaching recovery: evidence for control by cytoskeletal interactions.

Band 3, the major intrinsic protein of the human erythrocyte membrane, was specifically labeled with the covalent fluorescent probe eosin isothiocyanate. The lateral mobility of labeled band 3 in the plane of the membrane under various conditions of ionic strength and temperature was examined by using the fluorescence photobleaching recovery technique. Low temperature (21 degrees C) and high ionic strength (46 mM NaPO(4)) favored immobilization of band 3(10% mobile) as well as slow diffusion of the mobile fraction (diffusion coefficient D = 4 x 10(-11) cm(2)sec(-1)). Increasing temperature (37 degrees C) and decreasing ionic strength (13 mM NaPO(4)) led to an increase in the fraction of mobile band 3(90% mobile) and a reversible increase in the diffusion rate of the mobile fraction (D = 200 x 10(-11) cm(2)sec(-1)). The increase in the fraction of mobile band 3 was markedly dissociated, however, from the increase in the diffusion rate of the mobile fraction. Thus, the fraction of mobile band 3 always increased at higher ionic strength and lower temperature than the ionic strength and temperature at which the diffusion rate increased. This dissociation was manifested kinetically on prolonged incubation of ghosts at constant ionic strength and temperature: the diffusion rate of the mobile fraction increased slowly at first and much more rapidly after the initial lag period, whereas the fraction of mobile band 3 increased almost immediately to 90% and remained maximal for the duration of the experiment. Further, changes in diffusion rate with temperature were promptly and totally reversible, whereas increases in the mobile fraction were only slowly and partially reversible. These effects were shown not to be due to complete dissociation of spectrin, the major protein of the erythrocyte cytoskeleton, from the membrane. This evidence suggests control of band 3 lateral mobility by at least two separate processes. The process that determines the diffusion coefficient of the mobile band 3 is completely reversible, and it probably involves a metastable state of cytoskeleton structure intermediate between tight binding to the membrane and complete dissociation from it.

Cytoskeleton↗

Molecules at the external nuclear surface. Sialic acid of nuclear membranes and electrophoretic mobility of isolated nuclei and nucleoli.

The molecules occurring as terminal residues on the external surfaces of nuclei prepared from rat liver by either sucrose-CaCl(2) or citric acid methods and nucleoli derived from the sucrose-CaCl(2) nuclei were studied chemically and electrokinetically. In 0.0145 M NaCl, 4.5% sorbitol, and 0.6 mM NaHCO(3) with pH 7.2 +/- 0.1 at 25 degrees C, the sucrose-CaCl(2) nuclei had an electrophoretic mobility of -1.92 microm/s/V/cm, the citric acid nuclei, -1.63 microm/s/V/cm, and the nucleoli, -2.53 microm/s/V/cm. The citric acid nuclei and the nucleoli contained no measurable sialic acid. The sucrose-CaCl(2) nuclei contained 0.7 nmol of sialic acid/mg nuclear protein; this was essentially located in the nuclear envelope. Treatment of these nuclei with 50 microg neuraminidase/mg protein resulted in release of 0.63 nmol of sialic acid/mg nuclear protein; treatment with 1 % trypsin caused release of 0.39 nmol of the sialic acid/mg nuclear protein. The pH-mobility curves for the particles indicated the sucrose-CaCl(2) nuclei surface had an acid-dissociable group of pK. approximately 2.7 while the pK for the nucleoli was considerably lower. Nucleoli treated with 50 microg neuraminidase/mg particle protein had a mobility of -2.53 microm/s/V/cm while sucrose-CaCl(2) nuclei similarly treated had a mobility of -1.41 microm/s/V/cm. Hyaluronidase at 50 microg/mg protein had no effect on nucleoli mobility but decreased the sucrose-CaCl(2) nuclei mobility to -1.79 microm/s/V/cm. Trypsin at 1 % elevated the electrophoretic mobility of the sucrose-CaCl(2) nuclei slightly but decreased the mobility of the nucleoli to -2.09 microm/s/V/cm. DNase at 50 microg/mg protein had no effect on the mobility of the isolated sucrose-CaCl(2) nuclei but decreased the electrophoretic mobility of the nucleoli to -1.21 microm/s/V/cm. RNase at 50 microg/mg protein also had no effect on the electrophoretic mobility of the sucrose-CaCl(2) nuclei but decreased the nucleoli mobility to -2.10 microm/s/V/cm. Concanavalin A at 50 microg/mg protein did not alter the nucleoli electrophoretic mobility but decreased the sucrose-CaCl(2) nuclei electrophoretic mobility to -1.64 microm/s/V/cm. The results are interpreted to mean that the sucrose-CaCl(2) nuclear external surface contains terminal sialic acid residues in trypsin-sensitive glycoproteins, contains small amounts of hyaluronic acid, is completely devoid of nucleic acids, and binds concanavalin A. The nucleolus surface is interpreted to contain a complex made up of protein, RNA, and primarily DNA, to be devoid of sialic acid and hyaluronic acid, and not to bind concanavalin A.

Animals↗

Mutations in the Lactococcus lactis Ll.LtrB group II intron that retain mobility in vivo.

BACKGROUND: Group II introns are mobile genetic elements that form conserved secondary and tertiary structures. In order to determine which of the conserved structural elements are required for mobility, a series of domain and sub-domain deletions were made in the Lactococcus lactis group II intron (Ll.LtrB) and tested for mobility in a genetic assay. Point mutations in domains V and VI were also tested. RESULTS: The largest deletion that could be made without severely compromising mobility was 158 nucleotides in DIVb(1-2). This mutant had a mobility frequency comparable to the wild-type Ll.LtrB intron (DeltaORF construct). Hence, all subsequent mutations were done in this mutant background. Deletion of DIIb reduced mobility to approximately 18% of wild-type, while another deletion in domain II (nts 404-459) was mobile to a minor extent. Only two deletions in DI and none in DIII were tolerated. Some mobility was also observed for a DIVa deletion mutant. Of the three point mutants at position G3 in DV, only G3A retained mobility. In DVI, deletion of the branch-point nucleotide abolished mobility, but the presence of any nucleotide at the branch-point position restored mobility to some extent. CONCLUSIONS: The smallest intron capable of efficient retrohoming was 725 nucleotides, comprising the DIVb(1-2) and DII(ii)a,b deletions. The tertiary elements found to be nonessential for mobility were alpha, kappa and eta. In DV, only the G3A mutant was mobile. A branch-point residue is required for intron mobility.

Journal Article↗

The dynamic mobility of vertebral compression fractures.

We have observed that some osteoporotic vertebral compression fractures (VCFs) are mobile. The purpose of this report was to document the existence of dynamic fracture mobility, estimate the frequency of dynamic mobility in patients referred for vertebroplasty, define the magnitude and nature of dynamic mobility, and consider the implications of the dynamic mobility of osteoporotic VCFs. This was a prospective radiographic analysis of 41 consecutive patients with 65 VCFs who underwent vertebroplasty. Preoperative standing lateral radiographs of the fractured vertebrae were compared with supine cross-table lateral radiographs to determine the presence or absence of dynamic mobility. Postoperative standing lateral radiographs were evaluated to document fracture mobility and assess final vertebral height restoration. Radiographs were manually digitized to calculate vertebral body morphometrics. Dynamic fracture mobility was demonstrated in 44% of patients (35% of treated vertebrae) who underwent vertebroplasty. Postoperatively, in mobile fractures, average anterior vertebral height increased 106% compared with initial fracture height (absolute increase, 8.41 +/- 0.4 mm). Mean lateral vertebral area increased from 48% to 80% of normal, and kyphotic angle decreased 40%. Mobile fractures dominated at the thoracolumbar junction. Intravertebral clefts were defined and identified in every mobile fracture and were absent from every nonmobile (fixed) fracture. This radiographic series documents the previously unrecognized occurrence of dynamic fracture mobility in many osteoporotic VCFs. Fracture mobility can be substantial and clinically significant. Any intervention that claims vertebral height restoration must control for the occurrence of dynamic fracture mobility.

Aged↗

Intergenerational social mobility: the United States in comparative perspective.

Emily Beller and Michael Hout examine trends in U.S. social mobility, especially as it relates to the degree to which a person's income or occupation depends on his or her parents' background and to the independent contribution of economic growth. They also compare U.S. social mobility with that in other countries. They conclude that slower economic growth since 1975 and the concentration of that growth among the wealthy have slowed the pace of U.S. social mobility. In measuring mobility, economists tend to look at income and sociologists, occupation. The consensus among those measuring occupational mobility is that the average correlation between the occupations of fathers and sons today ranges from 0.30 to 0.40, meaning that most variation in the ranking of occupations is independent of social origins. Those measuring income mobility tend to agree that the elasticity between fathers' and sons' earnings in the United States today is about 0.4, meaning that 40 percent of the difference in incomes between families in the parents' generation also shows up in differences in incomes in the sons' generation. Beller and Hout show that occupational mobility increased during the 1970s, compared with the 1940s-1960s, but there is some evidence to suggest that by the 1980s and 1990s it had declined to past levels. Existing data on income mobility show no clear trends over time, but increases in economic inequality during the 1980s made mobility more consequential by making economic differences between families persist for a longer time. In international comparisons, the United States occupies a middle ground in occupational mobility but ranks lower in income mobility. Researchers have used the variation in mobility to study whether aspects of a country's policy regime, such as the educational or social welfare systems, might be driving these results. There is as yet, however, no scholarly consensus about the sources of cross-national differences in mobility.

Career Mobility↗

Health-related mobility, health inequalities and gradient constraint. Discussion and results from a Norwegian study.

BACKGROUND: Recent studies have argued that health-related mobility does not widen social class health differentials, but rather moderates them. This is termed gradient constraint. This paper examines gradient constraint from a theoretical and empirical angle. METHODS: How health-related mobility influences social class health differentials is discussed using hypothetical models. In a Norwegian survey with data on intergenerational mobility (N = 1,853 males aged 30-69 years), mean health and height values for different subsections of the sample were analysed. RESULTS: When initial social class health differences are large and mobility widespread, health-related mobility may lead to smaller differentials, but the result depends on how closely mobility varies with health. This empirical study found non-significant increases in height and health differentials from class of origin to class of destination. The interpretation has to consider effects of both social mobility and social causation. Health is measured in the post-mobility situation and the effects of social mobility and social causation are difficult to separate from each other for most of the health indicators analysed. However, this limitation does not apply to height which is not influenced by social causation during adulthood. In these data mobility did not reduce the height differential. CONCLUSION: Health-related mobility can either lead to smaller or larger social class health differentials. The specific effects of social mobility cannot be determined without knowing how social causation has interfered. The intergenerational mobility process analysed in this paper does not show gradient constraint as regards the height differential between the worker and higher occupational categories.

Adult↗

Occupational mobility and risk factors in working men: selection, causality or both? Results from the GAZEL study.

OBJECTIVE: To explore the relation between risk factors (RF) and occupational mobility in working men. SETTING: 20 000 volunteers working at the French National Electricity and Gas Company (GAZEL cohort). PARTICIPANTS: Men aged 43 to 53 years in 1992. DESIGN: Three designs were used for analysis. (1) The association between occupational mobility experienced before 1992 and RF reported at that date was analysed among 10 383 men. (2) The predictive role of RF on occupational mobility over 1992-1999 was studied in a subsample of 4715 men. (3) Reciprocally, occupational mobility in 1985-1992 was analysed in relation to RF changes over 1993-1999. MAIN OUTCOME MEASURES: Self reported smoking status, excessive alcohol consumption, arterial hypertension, and overweight. Occupational mobility defined by any upward transition between senior executives and professionals/middle executives/employees, and workers. RESULTS: (1) Cross sectionally, non-mobile men as their entry into the company had a higher risk of being smokers, excessive alcohol drinkers, and overweight in 1992 than mobile men. (2) Longitudinally, smokers and excessive alcohol drinkers in 1992 had a higher risk of non-mobility than, respectively, non-smokers and non-excessive alcohol drinkers. (3) Non-mobile men in 1985-1992 had a higher risk of becoming smokers, excessive alcohol drinkers, and hypertensive in 1993-1999 than upwardly mobile men. CONCLUSION: These results suggest a complex relation between RF and occupational mobility. A high level of RF, particularly health behaviours, might account for a selection process reducing upward occupational mobility. In turn, a lack of upward occupational mobility might be associated with an increased incidence of RF.

Adult↗

AMD3100 mobilizes hematopoietic stem cells with long-term repopulating capacity in nonhuman primates.

AMD3100, a bicyclam antagonist of the chemokine receptor CXCR4, has been shown to induce rapid mobilization of CD34(+) hematopoietic cells in mice, dogs, and humans, offering an alternative to G-CSF mobilization of peripheral-blood hematopoietic stem cells. In this study, AMD3100-mobilized CD34(+) cells were phenotypically analyzed, marked with Neo(R)-containing retroviral vectors, and subsequently transplanted into myeloablated rhesus macaques. We show engraftment of transduced AMD3100-mobilized CD34(+) cells with Neo(R) gene marked myeloid and lymphoid cells up to 32 months after transplantation, demonstrating the ability of AMD3100 to mobilize true long-term repopulating hematopoietic stem cells. More AMD3100-mobilized CD34(+) cells are in the G(1) phase of the cell cycle and more cells express CXCR4 and VLA-4 compared with G-CSF-mobilized CD34(+) cells. In vivo gene marking levels obtained with AMD3100-mobilized CD34(+) cells were better than those obtained using CD34(+) cells mobilized with G-CSF alone. Overall, these results indicate that AMD3100 mobilizes a population of hematopoietic stem cells with intrinsic characteristics different from those of hematopoietic stem cells mobilized with G-CSF, suggesting fundamental differences in the mechanism of AMD3100-mediated and G-CSF-mediated hematopoietic stem cell mobilization. Thus, AMD3100-mobilized CD34(+) cells represent an alternative source of hematopoietic stem cells for clinical stem cell transplantation and genetic manipulation with integrating retroviral vectors.

Animals↗

Pilot trial of interleukin-2 with granulocyte colony-stimulating factor for the mobilization of progenitor cells in advanced breast cancer patients undergoing high-dose chemotherapy: expansion of immune effectors within the stem-cell graft and post-stem-cell infusion.

PURPOSE: To evaluate whether administration of interleukin-2 (IL-2) with granulocyte colony-stimulating factor (G-CSF) improves mobilization of immune effector cells into the stem-cell graft of patients undergoing high-dose chemotherapy and autografting. PATIENTS AND METHODS: We performed a trial of stem-cell mobilization with IL-2 and G-CSF in advanced breast cancer patients receiving high-dose chemotherapy with cyclophosphamide, thiotepa, and carboplatin and stem cells followed by IL-2. The trial defined immune, hematologic, and clinical effects of IL-2 in this setting. RESULTS: Of 32 patients enrolled, nine received G-CSF alone for mobilization. Twenty-one of 23 patients mobilized with IL-2 plus G-CSF had stem cells collected with more mononuclear cells than those receiving G-CSF (19.3 v 10.4 x 10(8)/kg; P =.006), but fewer CD34(+) progenitor cells (6.9 v 22.0 x 10(6)/kg; P =.049). The IL-2 plus G-CSF-mobilized patients had greater numbers of activated T (CD3(+)/CD25(+)) cells (P =.009), natural killer (NK; CD56(+)) cells (P =.007), and activated NK (CD56 bright(+)) cells (P: =.039) than those patients mobilized with G-CSF. NK (P =.042) and lymphokine-activated killer (LAK) (P =.016) activity was increased in those mobilized with IL-2 + G-CSF, whereas G-CSF-mobilized patients had a decline in cytolytic activity. In the third week posttransplantation, immune reconstitution was superior in those mobilized with IL-2 plus G-CSF based on greater numbers of activated T cells (P =.003), activated NK cells (P =.04), and greater LAK activity (P =.003). The 16 of 21 IL-2 + G-CSF-mobilized patients with adequate numbers of stem cells (> 1.5 x 10(6) CD34(+) cells/kg) collected engrafted rapidly posttransplantation. CONCLUSION: The results demonstrate that G-CSF + IL-2 can enhance the number and function of antitumor effector cells in a mobilized autograft without impairing the hematologic engraftment, provided that CD34 cell counts are more than 1.5 x 10(6) cells/kg. Mobilization of CD34(+) stem cells does seem to be adversely affected. In those mobilized with IL-2 and G-CSF, post-stem-cell immune reconstitution of antitumor immune effector cells was enhanced.

Adult↗

Expression of adhesion molecules on CD34(+) cells in peripheral blood of non-hodgkin's lymphoma patients mobilized with different growth factors.

Adhesion molecules on CD34(+) cells were implicated in the process of peripheral blood stem cell (PBSC) mobilization and homing. We studied the mobilization of CD34(+)Thy1(+) cells, CD34(+) very late-acting antigen (VLA)4(+) cells, and CD34(+)L-selectin(+) cells in non-Hodgkin's lymphoma patients mobilized with cyclophosphamide plus G-CSF, GM-CSF, or GM-CSF followed by G-CSF. The mean percentage of CD34(+) cells in the bone marrow (BM) expressing Thy1 was 23.6% +/- 11% and 17.8% +/- 8% in the PB before mobilization, and was markedly decreased to 4.5% +/- 3.3% in the apheresis collections. Similarly, the mean percentage of CD34(+) cells expressing L-selectin was 35.8% +/- 4.3% in the BM, 21.6% +/- 4.1% in the PB before mobilization and was markedly decreased to 9.1% +/- 2.5% in the apheresis collections. Patients in the three arms of the study had a similar pattern of CD34(+)Thy1(+) and CD34(+)L-selectin(+) cell mobilization. Also, a similar pattern of coexpression of CD34(+)Thy1(+) and CD34(+)L-selectin(+) cells was observed when the patients were regrouped as "good mobilizers" (> or =2 x 10(6) CD34(+)CD45(dim) cells/kg, in four collections) and "poor mobilizers" (<0.4 x 10(6) CD34(+)CD45(dim) cells/kg, in two collections). The mean percentage of CD34(+) cells expressing VLA-4 in the BM and PB was relatively high (73.4% +/- 12% and 65.4% +/- 6.6%, respectively) and dropped considerably in the PBSC collections to 43.5% +/- 7.1% with a similar pattern observed for patients in arms A, B, and C. However, when the patients were regrouped as "good mobilizers" and "poor mobilizers," a higher percentage of CD34(+) cells expressing VLA-4 was observed in the PBSC of the pooled "good mobilizers" (50.5% +/- 9% versus 36.3% +/- 6.4%; p = 0.01). We conclude that release of CD34(+) cells to the PB involves a general downregulation of Thy1, L-selectin and VLA-4 on CD34(+) cells, irrespective of the growth factor used for mobilization. However, good mobilizers had a relatively higher percentage of CD34(+) cells expressing the VLA-4 antigen.

Adult↗

Influence of standardized mobilization on the posteroanterior stiffness of the lumbar spine in asymptomatic subjects.

BACKGROUND AND PURPOSE: Spinal mobilization is commonly used to relieve pain and assist recovery of mobility in individuals with low back pain. Fundamental to this concept is the belief that spinal mobilization will influence the mechanical properties of the symptomatic motion segment. The objective of the present study was to examine the segmental effects of a standardized mobilization procedure on the posteroanterior (PA) stiffness of the lumbar spine. METHOD: Audio and visual feedback was used to train a physiotherapist to perform PA mobilization at a consistent load and frequency. After training, twenty-four subjects without low back pain were recruited for the intervention phase of the study. The spinal posteroanterior mobilization (SPAM) apparatus was used to measure the PA stiffness of the lumbar spine at three measurement sites (L1, L3 and L5). The trained physiotherapist then applied the standardized PA mobilization technique via the L3 spinous process for two minutes. Following mobilization, PA stiffness was measured three times at the three locations. RESULTS: The physiotherapist was able to apply a standardized mobilization with a mean force of 146 N (standard deviation (SD) 8 N) at a frequency of 1.5 Hz. The first trial on each assessment demonstrated a pre-condition effect. Two minutes' PA mobilization resulted in no significant change in the PA stiffness of the lumbar spine at the level to which the mobilization was applied, or at the L1 and L5 segments. The 95% confidence intervals (CI) of the difference in PA stiffness before and after testing included zero at each measurement site. CONCLUSIONS: Clinicians should pre-condition the spine when assessing PA stiffness both before and after interventions. A standardized mobilization of 150 N at 1.5 Hz for two minutes had no segmental effect on spinal PA stiffness. Subsequent studies need to consider other mechanisms that may contribute to the changes that occur after PA spinal mobilization.

Adult↗

Mobilization of peripheral blood progenitor cells by Betafectin PGG-Glucan alone and in combination with granulocyte colony-stimulating factor.

Betafectin PGG-Glucan, a novel beta-(1,6) branched beta-(1,3) glucan purified from the cell walls of Saccharomyces cerevisiae, has been shown to synergize with myeloid growth factors in vitro and to enhance hematopoietic recovery in myelosuppressed mice and primates. Here we report that PGG-Glucan is also capable of mobilizing peripheral blood progenitor cells (PBPC). PGG-Glucan (0.5 mg/kg to 16 mg/kg) was administered intravenously to C3H/HeN male mice and blood collected at times ranging from 30 min to seven days after injection. Based on granulocyte-macrophage colony-forming cell (GM-CFC) levels, peak mobilization occurred 30 min after a 2 mg/kg PGG-Glucan dose. At this time GM-CFC numbers in PGG-Glucan-treated mice were approximately fourfold greater than in saline-treated control mice. A second, smaller wave of GM-CFC mobilization (approximately twofold increase) also occurred on days 4 and 5 after PGG-Glucan treatment. Mobilization was not associated with the induction of alpha-chemokines, which have recently been reported to induce rapid progenitor cell mobilization. Competitive repopulation experiments performed in irradiated female C3H/HeN mice revealed that, at three months after transplantation, more male DNA was present in bone marrow, splenic, and thymic tissues from animals transplanted with cells obtained from mice 30 min after a 2 mg/kg PGG-Glucan dose than in tissues from animals transplanted with cells obtained from saline-treated mice. Additional experiments evaluated the mobilization effects of PGG-Glucan (2 mg/kg) administered to mice which had been pretreated for three consecutive days with G-CSF (125 microg/kg/day). When blood was collected 30 min after PGG-Glucan treatment, the number of GM-CFC mobilized in combination-treated mice was additive between the number mobilized in mice treated with G-CSF alone and the number mobilized in mice treated with PGG-Glucan alone. These studies demonstrate that: A) PGG-Glucan can rapidly mobilize PBPC; B) the kinetic pattern of PGG-Glucan-induced mobilization is different from that of the CSFs; C) the reconstitutional potential of PGG-Glucan mobilized cells is greater than that of steady-state PBPC, and D) PGG-Glucan can enhance G-CSF-mediated PBPC mobilization.

Adjuvants, Immunologic↗

Road mobility and the risk of road traffic accident as a driver. The impact of medical conditions and life events.

STUDY OBJECTIVE: We conducted a longitudinal investigation of the impact of self-reported life events and medical conditions on changes in road mobility on the wheel between 2000 and 2002 in order to assess whether these changes would affect the risk of road traffic accident (RTA). METHODS: Data are from a cohort of workers and retirees from the French national gas and electricity companies (the Gazel cohort). In the present study, 10,483 participants were included (7843 men aged 51-61 years and 2640 women aged 46-61 years, in 2000). The link between mobility and the risk of RTA was approximated using data on RTA number during lifetime and reported mobility in 2000. We then compared changes in road mobility between 2000 and 2002 resulting from life events and medical conditions reported to have occurred in the year 2001 or changed when compared to year 2000. We also compared road mobilities in 2000 in order to assess any pre-existing differences before life events and medical conditions. This led to estimation of the effect of road mobility changes on the risk of RTA. RESULTS: Changes in road mobility associated with life events and medical conditions were only found among men. These changes in road mobility were minimal. Ensuing changes in the risk of RTA were estimated to be small (odds-ratios ranged from 0.94 to 1.01). The only life events found to be associated with increased road mobility was an important purchase. Hospitalization, serious RTA, and retiring were associated with reduced road mobility. Concerning medical conditions, men who reported cataract, angina pectoris, diabetes, anxiety and stress, sleep disorder, and depression decreased their road mobility. CONCLUSION: We found no or moderate changes in road mobility resulting from life events and medical conditions, suggesting that results from previous published studies that assessed the impact of life events or medical conditions on RTA were not jeopardized by improper adjustment for road mobility.

Accidents, Traffic↗

The influence of surgical malalignment on the contact pressures of fixed and mobile bearing knee prostheses--a biomechanical study.

OBJECTIVE: To investigate the effect of surgical malalignment on contact pressures of fixed and mobile bearing knee prostheses. DESIGN: An experimental set-up was used to measure contact pressure on the tibial component of fixed and mobile bearing knee prostheses subjected to a compression load and surgical malalignment situations were simulated. BACKGROUND: Mobile bearing knee prostheses were designed to decrease tibiofemoral contact pressure by providing both high congruity and mobility. It was also assumed to accommodate surgical malalignment. However, few studies have reported the effect of malalignment of the tibiofemoral joint on contact pressure of fixed and mobile bearing knee prostheses. METHODS: Surgical malalignment situations were simulated to evaluate contact characteristics of tibial component of fixed and mobile bearing knee prostheses. The simulated malalignment conditions include the medial-lateral translation (0.5 and 1 mm), anterior-posterior translation (2 and 4 mm) and internal-external rotation (1 degrees, 3 degrees, 5 degrees and 10 degrees ) of the femoral component relative to the tibial component. Fuji pressure sensitive film was used to measure the contact pressure. RESULTS: The greatest increase of maximum contact pressure in the anterior-posterior maltranslation was 7.63% and 7.62% relative to the neutral contact situation in the fixed and mobile bearing designs respectively. In the medial-lateral maltranslation, there was 23.3% in the fixed bearing design and was 22.0% in the mobile bearing design. In the internal/external malrotation, the greatest increase of maximum contact pressure in the fixed bearing design was 27.1%, which was much higher than the mobile bearing design (22.4%). CONCLUSIONS: The mobile bearing design can reduce maximum contact pressure more significantly than the fixed bearing design when malalignment conditions of the tibiofemoral joint occurs, especially in the internal/external malrotation. The mobile bearing design offers the advantage of self-adjusting over the fixed bearing design to accommodate surgical malalignment. RELEVANCE: This study revealed that the mobile bearing design has smaller maximum contact pressures than the fixed bearing design in knee prosthesis under malalignment biomechanical tests. This result indicates that there is an advantage for a mobile bearing design over a fixed bearing design to accommodate malalignment conditions caused by surgical technique or soft tissues imbalance in total knee arthroplasty.

Arthroplasty, Replacement, Knee↗

The meaning of mobility for residents and staff in long-term care facilities.

BACKGROUND: Although the physical and psychological effects of decreased mobility have been documented, little is known about what it means to be mobile from the institutionalized elders' perspective. Even less is known about nurses' perceptions regarding institutionalized elders' mobility and about mobility enhancing strategies. AIM: The purpose of this study was to generate knowledge about the phenomenon of mobility from both the nurses' and institutionalized elders' perspective. DESIGN: An exploratory qualitative design was used. Focus groups with residents and nursing staff were conducted in three long-term care facilities in a large metropolitan city in 1998. Ethical approval was received from the ethics committees in all three facilities prior to study implementation. Twenty long-term care facility residents and 15 nursing staff participated in the study. METHODS: A trained facilitator used an interview guide to moderate discussions in which residents' and nurses' opinions and feelings about mobility were solicited. The group responses were tape recorded, transcribed and coded. The codes reflected major concepts or abstractions of the data and emerged from the participants' verbal responses to the research questions. FINDINGS: Both groups identified mobility as being pivotal to the residents' quality of life and well-being. The residents viewed mobility as a means of freedom, choice and independence, and they made great efforts to maintain their mobility. The nurses also valued the importance of mobility and assisted the residents through preparatory care, environmental modifications and encouragement. Factors that related to the residents' willingness to be mobile, environmental barriers and the impact of waiting were compared between the two groups. CONCLUSION: Mobility involves more than the movement from one point to another. The nature of the assistive nurse-client relationship and the resident's subjective perspective must become central to understanding the meaning of mobility for residents in a long-term care facility.

Activities of Daily Living↗

Fibronectin receptor exhibits high lateral mobility in embryonic locomoting cells but is immobile in focal contacts and fibrillar streaks in stationary cells.

The dynamic process of embryonic cell motility was investigated by analyzing the lateral mobility of the fibronectin receptor in various locomotory or stationary avian embryonic cells, using the technique of fluorescence recovery after photobleaching. The lateral mobility of fibronectin receptors, labeled by a monoclonal antibody, was defined by the diffusion coefficient and mobile fraction of these receptors. Even though the lateral diffusion coefficient did not vary appreciably (2 X 10(-10) cm2/S less than or equal to D less than or equal to 4 X 10(-10) cm2/S) with the locomotory state and the cell type, the mobile fraction was highly dependent on the degree of cell motility. In locomoting cells, the population of fibronectin receptors, which was uniformly distributed on the cell surface, displayed a high mobile fraction of 66 +/- 19% at 25 degrees C (82 +/- 14% at 37 degrees C). In contrast, in nonmotile cells, the population of receptors was concentrated in focal contacts and fibrillar streaks associated with microfilament bundles and, in these sites, the mobile fraction was small (16 +/- 8%). When cells were in a stage intermediate between highly motile and stationary, the population of fibronectin receptors was distributed both in focal contacts with a small mobile fraction and in a diffuse pattern with a reduced mobile fraction (33 +/- 9%) relative to the diffuse population in highly locomotory cells. The mobile fraction of the fibronectin receptor was found to be temperature dependent in locomoting but not in stationary cells. The mobile fraction could be modulated by affecting the interaction between the receptor and the substratum. The strength of this interaction could be increased by growing cells on a substratum coated with polyclonal antibodies to the receptor. This caused the mobile fraction to decrease. The interaction could be decreased by using a probe, monoclonal antibodies to the receptor known to perturb the adhesion of certain cell types which caused the mobile fraction to increase. From these results, we conclude that in locomoting embryonic cells, most fibronectin receptors can readily diffuse in the plane of the membrane. This degree of lateral mobility may be correlated to the labile adhesions to the substratum presumably required for high motility. In contrast, fibronectin receptors in stationary cells are immobilized in focal contacts and fibrillar streaks which are in close association with both extracellular and cytoskeletal structures; these stable complexes appear to provide firm anchorage to the substratum.

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