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PubMed1989

Analysis of electrophoretic mobility histograms of mouse splenocytes and thymocytes during tumor growth and after combined chemotherapy and immunotherapy.

Changes in electrophoretic mobility histograms of splenocytes and thymocytes were studied in plasmacytoma X5563-bearing mice as an indicator of response to treatment with mitomycin C (MMC) alone or combined with the immunomodulator Krestin (PSK). Tumor growth was inhibited by 80-90% in the MMC-treated and was further inhibited in the MMC and PSK-treated group. Electrophoretic mobility histograms of splenocytes were used to determine the fraction of cells having intermediate mobility between high mobility (T cells) and low mobility (B cells). This fraction of intermediate-mobility cells increased in tumor-bearing mice, but a normal electrophoretic mobility pattern was obtained following successful antitumor treatment. In the electrophoretic mobility histogram of thymocytes, on the other hand, the low-mobility cells (cortical thymocytes) decreased in number during tumor growth and were further reduced in the MMC-treated group. This reduction was less in the MMC and PSK-treated group. These results suggest that combined therapy with MMC and PSK prevents damage of the host defence mechanism and allows more efficient antitumor treatment. Analysis of electrophoretic mobility histograms of splenocytes and thymocytes using a fully automated cell electrophoretic instrument makes possible the rapid evaluation of the immunological effects of drug therapy of tumor-bearing mice.

Animals↗

PubMed2006

Mobile phone use while driving in a sample of Spanish university workers.

A number of epidemiological studies have reported drivers who use a mobile phone while driving have an elevated risk of being involved in a crash. This is particularly concerning as a survey of drivers in the Spanish region of Catalunya found that approximately 87% own mobile phones. The present study investigated the reported frequency of mobile phone use on Spanish roads (for talking and using SMS), the characteristics of the drivers who use mobile phones while driving and whether they altered their driving behaviour when using a mobile phone. The research found that more than 60% use a mobile phone while driving and that the phone is mostly used for making calls, rather than using SMS. In general, males and females use mobile phones about the same reported frequency, although males were more likely to use a mobile phone to talk on the highway. The pattern for age was the same for both male and female participants, with the younger drivers using SMS more frequently than older drivers. On urban roads almost half of the drivers reported changing their driving behaviour when using a mobile phone, while on the highway this figure was slightly over 41%. The reported frequency of using a mobile phone to talk on urban roads was significantly correlated with crash involvement. However, this affect disappeared once the contributions of the demographic and descriptive variables had been partialled out.

Accidents, Traffic↗

PubMed1999

Mobile atheroma of the aortic arch and the risk of carotid artery disease.

BACKGROUND: Mobile atheromas of the aortic arch are associated with otherwise unexplained strokes and transient ischemic attacks (TIA). They are associated with increased perioperative strokes in patients undergoing coronary artery bypass surgery. Peripheral embolization is an additional risk. Transesophageal echocardiography (TEE) accurately identifies mobile atheroma. Anticoagulant therapy may have therapeutic considerations in the management of this condition. However, the risk of significant carotid artery disease associated with mobile atheromas is unknown. METHODS: Between March 1994 and July 1998, 40 patients with mobile atheromas by TEE and evidence of embolization were studied. All patients were captured prospectively in a vascular registry and were retrospectively reviewed. Carotid artery disease was evaluated using carotid duplex imaging in an accredited vascular laboratory. All patients with significant carotid disease, 70% or greater stenosis, underwent arteriography. Patients with significant carotid artery stenosis then underwent carotid endarterectomy. All patients with mobile atheromas were maintained on anticoagulation. RESULTS: Forty patients with mobile atheromas of the aortic arch were diagnosed with TEE. All 40 patients had evidence of embolization. Patient age ranged from 57 to 73 years (mean 68.4). There were 22 men and 18 women. Twenty of 40 (50%) patients presented with symptoms of TIA. Eleven of 40 (28%) patients presented with diffuse atheroembolization (lower extremity embolization and renal insufficiency). Six of 40 (15%) patients presented with a completed stroke. Three of 20 (7%) patients presented with acute extremity ischemia secondary to a peripheral embolus. Twenty-three of 40 (58%) of patients had significant carotid artery stenosis, 70% or greater stenosis. These 23 patients underwent both arteriography and carotid endarterectomy without complication. All patients were treated with anticoagulation and have remained anticoagulated. Clinical follow-up between 2 to 48 months (mean 18) has demonstrated no further evidence of systemic embolization in these 40 patients. Repeat TEE was performed in 6 of 40 patients. These follow-up studies no longer visualized mobile atheromas. CONCLUSIONS: Mobile atheromas are recognized sources for embolization. Routine carotid duplex imaging should be performed in patients found to have mobile atheromas of the aortic arch. Carotid endarterectomy appears to be safe in patients who have combined carotid artery stenosis and mobile atheromas. Anticoagulation may have therapeutic considerations in the management of this condition.

Aged↗

PubMed2001

Electrophoretic mobilities of cationic analytes in non-aqueous methanol, acetonitrile and their mixtures. Influence of ionic strength and ion-pair formation.

The mobilities of cationic analytes in organic solvents and water are compared, and the reasons for differences in the mobilities are discussed in detail. Actual mobilities (at background electrolyte concentration 10 mmol/l) of anilinium ions were determined by capillary zone electrophoresis in water, methanol, acetonitrile and mixtures of methanol and acetonitrile (in volume ratios 1:1, 1:3 and 3:1). The actual mobilities correlated with the viscosity of the organic solvent: the products of actual mobility and viscosity were constant within 7%. However, these products were significantly larger in water. Larger products of mobility and viscosity in water were also found for unsubstituted anilinium when the absolute mobility (at zero ionic strength) was taken into consideration. Thus, ion-solvent interactions must be responsible for the seemingly high mobility in water compared with that in organic solvents. This finding can be explained by the effect of the ion on the water structure. Based on equilibrium constant for ion-pair formation given in the literature, about 20% of the main background electrolyte constituent (tetrapropylammonium perchlorate) is associated at 10 mmol/l concentration in acetonitrile. Comparison of the plot of the measured mobilities of the analytes vs. the square root of the corrected ionic strength of the background electrolyte in acetonitrile with the prediction based on the Debye-Hückel-Onsager theory showed the measured mobilities deviate negatively from the theoretical line. This is apparently due to ion pairing, which takes place for the analytes as well.

Acetonitriles↗

PubMed2002

Mobilization of small DNAPL pools formed by capillary entrapment.

We performed an experimental study to quantify the critical conditions for the mobilization of small pools of dense nonaqueous phase liquids (DNAPLs) that may form at capillary-heterogeneity boundaries. A series of experiments were conducted in columns packed with uniform sands arranged to create capillary heterogeneities. DNAPL pools readily formed in these packings and were more easily mobilized than trapped DNAPL ganglia. A model was developed to describe the critical conditions for DNAPL pool mobilization. Pool mobilization was expected when a dimensionless pool trapping number N(T)p> 1 while mobilization was observed in our experiments when N(T)p>0.76+/-0.16 (+/- 95% confidence interval). The difference between the model prediction and the experimental observations was attributed to experimental error. Using this model for DNAPL pool mobilization, a simple numerical experiment was conducted to illustrate use of the model and to explore the effect of scale on the critical conditions for pool mobilization. With an increase in system scale flow bypassing around the DNAPL pool increased and the system-averaged conditions for the onset of mobilization changed: a greater system-average Darcy flux or lower interfacial tensions were required for DNAPL pool mobilization. This result illustrates the importance of system scale on mobilization of DNAPL pools in systems with capillary heterogeneities.

Models, Theoretical↗

PubMed2002

Contaminant transport in dual-porosity media with dissolved organic matter and bacteria present as mobile colloids.

In riverbank filtration, contaminant transport is affected by colloidal particles such as dissolved organic matter (DOM) and bacterial particles. In addition, the subsurface heterogeneity influences the behavior of contaminant transport in riverbank filtration. A mathematical model is developed to describe the contaminant transport in dual-porosity media in the presence of DOM and bacteria as mobile colloids. In the model development, a porous medium is divided into the mobile and immobile regions to consider the presence of ineffective micropores in physically heterogeneous riverbanks. We assume that the contaminant transport in the mobile region is controlled by the advection and dispersion while the contaminant transport in the immobile region occurs due to the molecular diffusion. The contaminant transfer between the mobile and immobile regions takes place by diffusive mass transfer. The mobile region is conceptualized as a four-phase system: two mobile colloidal phases, an aqueous phase, and a solid matrix. The complete set of governing equations is solved numerically with a fully implicit finite difference method. The model results show that in riverbank filtration, the contaminant can migrate further than expected due to the presence of DOM and bacteria. In addition, the contaminant mobility increases further in the presence of the immobile region in aquifers. A sensitivity analysis shows that in dual-porosity media, earlier breakthrough of the contaminant takes place as the volumetric fraction of the mobile region decreases. It is also demonstrated that as the contaminant mass transfer rate coefficient between the mobile and immobile regions increases, the contaminant concentration gradient between the two regions reverses at earlier pore volumes. The contaminant mass transfer coefficient between the mobile and immobile regions mainly controls the tailing effect of the contaminant breakthrough. The contaminant breakthrough curves are sensitive to changes in contaminant adsorption and desorption rate coefficients on DOM and bacteria. In situations where the contaminant is released in the presence of DOM and bacteria in dual-porosity media, the early breakthrough and tailing occur due to the colloidal facilitation and presence of immobile regions.

Adsorption↗

PubMed1997

Lumbar mobility in former élite male weight-lifters, soccer players, long-distance runners and shooters.

OBJECTIVE: To investigate the long-term effects of different loading conditions in sports and work on lumbar mobility. DESIGN: Factors associated with lumbar mobility were sought by examining sports experience, occupational history, back pain history, anthropometric characteristics, and lumbar magnetic resonance images in 114 former Finnish male élite athletes: 30 soccer players, 29 weight-lifters, 27 long-distance runners, and 28 shooters, aged 45-68 yr. BACKGROUND: Back pain and aging reduce spinal mobility, whereas some sports may increase it. Little is known about the effects of common loading conditions found in work and sports, that do not require extremes of spinal motion on lumbar mobility later in life. METHODS: Sports and occupational histories were obtained from a standardized interview. Lumbar mobility was measured by the flexicurve method. Disc degeneration was evaluated from lumbar magnetic resonance images. The results were analysed with analysis of variance and covariance and multiple regression models. RESULTS: The athlete groups did not differ significantly in lumbar sagittal mobility. Higher body-mass index was associated with less flexion, reduced disc height with less extension, as was a high lifetime number of low back pain episodes. Occupations characterized by varying work postures and light lifting were associated with greater mobility, and heavy work with lesser mobility. CONCLUSIONS: Participation in sports with clearly different loading patterns, that do not emphasize extremes of spinal range of motion, do not appear to lead to significant differences in back mobility in later adulthood, but occupational loading factors and disc height narrowing appear to influence spinal mobility.

Journal Article↗

PubMed1998

Mobile aortic atheroma and systemic emboli: efficacy of anticoagulation and influence of plaque morphology on recurrent stroke.

OBJECTIVES: We sought to determine the influence of plaque morphology and warfarin anticoagulation on the risk of recurrent emboli in patients with mobile aortic atheroma. BACKGROUND: An epidemiologic link between aortic atheroma and systemic emboli has been described both in pathologic and transesophageal studies. Likewise, a few studies have found an increased incidence of recurrent emboli in these patients. The therapeutic implications of these findings has not been studied. METHODS: Thirty-one patients presenting with a systemic embolic event and found to have mobile aortic atheroma were studied. The height, width and area of both immobile and mobile portions of atheroma were quantitated. The dimensions of the mobile component was used to define three groups: small, intermediate and large mobile atheroma. The patients were followed up by means of telephone interview and clinical records, with emphasis on anticoagulant use and recurrent embolic or vascular events. RESULTS: Patients not receiving warfarin had a higher incidence of vascular events (45% vs. 5%, p = 0.006). Stroke occurred in 27% of these patients and in none of those treated with warfarin. The annual incidence of stroke in patients not taking warfarin was 0.32. Myocardial infarction occurred in 18% of patients also in this group. Taken together, the risk of myocardial infarction or stroke was significantly increased in this group (p = 0.001). Forty-seven percent of patients with small, mobile atheroma did not receive warfarin. Recurrent stroke occurred in 38% of these patients, representing an annual incidence of 0.61. There were no strokes in patients with small, mobile atheroma treated with warfarin (p = 0.04). Likewise, none of the patients with intermediate or large mobile atheroma had a stroke during follow-up. Only three of these patients had not been taking warfarin. CONCLUSIONS: Patients presenting with systemic emboli and found to have mobile aortic atheroma on transesophageal echocardiography have a high incidence of recurrent vascular events. Warfarin is efficacious in preventing stroke in this population. The dimension of the mobile component of atheroma should not be used to determine the need for anticoagulation.

Aged↗

PubMed2003

Increasing esophageal length: a comparison of laparoscopic versus transthoracic esophageal mobilization with and without vagal trunk division in pigs.

BACKGROUND: New laparoscopic techniques allow both mediastinal mobilization and performance of a Collis gastroplasty when necessary, and the utility of a transthoracic approach is questioned. The aim of this study was to compare the increase in esophageal length achievable with laparoscopic and transthoracic esophageal mobilization in pigs, and to assess the impact of vagal trunk division on esophageal length. STUDY DESIGN: Baseline esophageal length was obtained in 20 farm pigs by measuring the distance between a stitch placed in the esophagus to a K-wire placed in a vertebral body. Subsequently, laparoscopic and then transthoracic mediastinal mobilization of the esophagus were performed in 15 pigs and the length gain after each procedure recorded. In 7 of 15 animals, the vagal nerve trunks were divided after esophageal mobilization and the increase in esophageal length measured. In five animals, vagal trunk division was performed without earlier esophageal mobilization. RESULTS: Esophageal length gain after laparoscopic mobilization (median 4 mm) was significantly less than that after transthoracic mobilization (median 12 mm, p < 0.0001). Unilateral vagal nerve transection resulted in a median 2.5 mm of esophageal length gain compared with a median of 6.25 mm with division of both vagal trunks. Maximal esophageal lengthening (median 18.5 mm) occurred with a combination of esophageal mobilization and bilateral vagal trunk division. CONCLUSIONS: Esophageal length gain after transthoracic mobilization in normal pigs is significant, and would likely be even greater in patients with gastroesophageal reflux disease with concomitant mediastinal inflammation. Transthoracic mobilization alone likely will allow successful reduction of the gastroesophageal junction below the diaphragm in many patients who might otherwise require a Collis gastroplasty.

Animals↗

PubMed1999

Electrosmotic mobility and conductivity in columns for capillary electrochromatography.

Columns employed so far in capillary electrochromatography (CEC) contain both a packed and an open segment with concomitant changes of the electric field strength and the flow velocity at the interface of the two segments in such duplex columns. To take this into account in measuring, processing, and interpreting CEC data, a framework is presented for the evaluation of the conductivity ratio and the interstitial electrosmotic flow (EOF) mobility and their usage as tools for characterizing CEC columns. This is illustrated by experimental data obtained from measurement of the current and the EOF in capillary columns packed with different stationary phases. The current data yielded the ratio of the conductivities of the packed and open segments that has been shown to be useful for the evaluation of the porosity and tortuosity. It is assumed that these important packing characteristics are the same for the flow of current and for the flow of the bulk mobile phase in the CEC column. The EOF mobility in such duplex columns is defined in two different ways. The apparent mobility, which is widely reported at present, is obtained from the length of packed segment, the migration time, and the overall electric field strength. On the other hand, the actual mobility is obtained after taking into account the porosity and tortuosity of the packing as well. Thus, the actual mobility is made independent of the porosity and tortuosity and therefore can be useful to estimate the zeta potential for characterizing the packing surface. Measurements of both the apparent and actual electrosmotic mobilities for a number of different columns have shown that the apparent and actual mobilities are significantly different in their magnitude. For this reason, it is recommended that, instead of the apparent EOF mobility, the actual mobility is used for the characterization of the packing in CEC columns.

Chromatography, Liquid↗

PubMed2002

Reduced atmospheric CO2 inhibits nitrogen mobilization in Festuca rubra.

In defoliated grasses, where photosynthesis is reduced due to removal of leaf material, it is well established that remobilization of nitrogen occurs from both older remaining leaves and roots towards the younger growing leaves. In contrast, little is known about the movement of nitrogen within intact grass plants experiencing prolonged inhibition of photosynthesis. We tested the following hypotheses in Festuca rubra L. ssp. rubra cv. Boreal: that both reduction of the atmospheric CO2 concentration and defoliation (1) induce mobilization of nitrogen from roots and older leaves towards growing leaves and (2) elicit similar directional change in the abundance of proteins in roots and older leaves relevant to the process of nitrogen mobilization including, glutamine synthetase (GS), EC 6.3.1.2; papain, EC 3.4.22.2; chymopapain, EC 3.4.22.6; ribulose bisphosphate carboxylase/oxygenase (Rubisco), EC 4.1.1.39; and the light harvesting complex of photosystem II (LHCPII). After growth at ambient atmospheric CO2 concentration, plants of F. rubra were subject to atmospheres containing either ambient (350 micro l l-1) or deplete (< 20 micro l l-1) CO2. Concurrently, plants were either left intact or defoliated on one occasion. Steady state 15N labelling coupled with a series of destructive harvests over a 7-day period enabled changes in the nitrogen dynamics of the plants to be established. Proteins pertinent to the process of nitrogen mobilization were quantified by immunoblotting. Irrespective of defoliation, plants in ambient CO2 mobilized nitrogen from older to growing leaves. This mobilization was inhibited by deplete CO2. Greater concentration of Rubisco and reduced chymopapain abundance in older remaining leaves of intact plants, in deplete compared with ambient CO2, suggested the inhibition of mobilization was due to inhibition of protein degradation, rather than to the export of degradation products. Both deplete CO2 and defoliation induced nitrogen mobilization from roots to growing leaves. In plants at ambient CO2, defoliation did not affect nitrogen uptake or its allocation. Therefore in F. rubra nitrogen mobilization can occur independently of any downregulation of nitrogen uptake. This suggests either different signal compounds may act to downregulate uptake and upregulate mobilization, or if one particular signalling compound is used its concentration threshold differs for induction of mobilization and downregulation of uptake. The abundance of the cysteine proteases papain and chymopapain was low in roots suggesting that they were not involved in protein degradation in this tissue.

Journal Article↗

PubMed2002

Expression of uncoupling proteins-1, -2 and -3 mRNA is induced by an adenocarcinoma-derived lipid-mobilizing factor.

The abnormalities of lipid metabolism observed in cancer cachexia may be induced by a lipid-mobilizing factor produced by adenocarcinomas. The specific molecules and metabolic pathways that mediate the actions of lipid-mobilizing factor are not known. The mitochondrial uncoupling proteins-1, -2 and -3 are suggested to play essential roles in energy dissipation and disposal of excess lipid. Here, we studied the effects of lipid-mobilizing factor on the expression of uncoupling proteins-1, -2 and -3 in normal mice. Lipid-mobilizing factor isolated from the urine of cancer patients was injected intravenously into mice over a 52-h period, while vehicle was similarly given to controls. Lipid-mobilizing factor caused significant reductions in body weight (-10%, P=0.03) and fat mass (-20%, P<0.01) accompanied by a marked decrease in plasma leptin (-59%, P<0.01) and heavy lipid deposition in the liver. In brown adipose tissue, uncoupling protein-1 mRNA levels were elevated in lipid-mobilizing factor-treated mice (+96%, P<0.01), as were uncoupling proteins-2 and -3 (+57% and +37%, both P<0.05). Lipid-mobilizing factor increased uncoupling protein-2 mRNA in both skeletal muscle (+146%, P<0.05) and liver (+142%, P=0.03). The protein levels of uncoupling protein-1 in brown adipose tissue and uncoupling protein-2 in liver were also increased with lipid-mobilizing factor administration (+49% and +67%, both P=0.02). Upregulation by lipid-mobilizing factor of uncoupling proteins-1, -2 and -3 in brown adipose tissue, and of uncoupling protein-2 in skeletal muscle and liver, suggests that these uncoupling proteins may serve to utilize excess lipid mobilized during fat catabolism in cancer cachexia.

Adenocarcinoma↗

PubMed1997

Effect of the in vivo priming regimen for peripheral blood stem cells (PBSC) mobilization on in vitro generation of cytotoxic effectors by IL-2 activation of PBSC in a murine model.

Priming of patients with different PBSC mobilizing regimens leads to an increase by several fold in circulating hematopoietic progenitors in peripheral blood. However, the effect of these mobilizing regimens on lymphoid cells contained within the harvested PBSC population is not well understood. We have studied the effect of CY and/or G-CSF +/- IL-2 containing regimens on lymphoid cells, and their capacity to give rise to cytotoxic effectors on subsequent in vitro IL-2 activation in a murine model of PBSC mobilization. C57B1/6 mice were given CY 100 or 200 mg/kg on day 0 followed 48 h later by G-CSF 125 micrograms/kg twice a day and/or IL-2 60000 i.u. twice a day in different schedules. Mice were sacrificed on day 4, 6, 8 and 10 following CY and the number of hematopoietic progenitors mobilized to the spleens of these mice was assessed by CFC assay and cytotoxicity was evaluated by 4 h 51Cr release assay against both NK-sensitive (Yak-1), and NK-resistant (B16, C1498) cell lines after 24 h in vitro IL-2 activation in the presence of 6000 i.u./ml of IL-2. Peak numbers of CFC in the splenic PBSC population were seen on day 6 following CY. Administration of CY 200 mg/kg + GCSF, the most potent regimen for CFC mobilization, led to a marked decrease in proportion of CD3+ cells in day 6 PBSC as compared to controls (17.7% vs 3.9%) and was associated with a significant decrease in generation of cytotoxic cells after IL-2 activation. Combining IL-2 to CY + G-CSF prevented the marked loss in cytotoxicity associated with this regimen without any decrease in number of CFC mobilized. When IL-2 was combined with CY without G-CSF, the number of CFC mobilized was comparable to that seen with CY + G-CSF and these CY + IL-2 mobilized PBSC generated potent cytotoxic effectors after in vitro IL-2 activation. Thus our results indicate that combining IL-2 with a PBSC mobilizing regimen can avert a decrease in the cytotoxic potential of mobilized cells without compromising the number of hematopoietic progenitors.

Animals↗

PubMed1997

Stem cell mobilization in resistant or relapsed lymphoma: superior yield of progenitor cells following a salvage regimen comprising ifosphamide, etoposide and epirubicin compared to intermediate-dose cyclophosphamide.

We analysed the factors influencing the efficacy of peripheral blood stem cell (PBSC) collection in patients with lymphoma. Sixty-six patients underwent initial PBSC collection following mobilization with chemotherapy plus recombinant granulocyte colony-stimulating factor (300 microg/d). Patients were mobilized with one of two chemotherapy regimens, either cyclophophamide (3 g/m2 or 4 g/m2) (n = 50) or ifosphamide, etoposide and epirubicin (IVE; n = 16). The target of collecting > 2.0 x 10(6) CD34+ cells/kg was achieved in 43/66 (65%) patients with a median of two apheresis procedures. The IVE plus G-CSF mobilization regimen gave a significantly higher median yield of CD34+ cells (8.62 x 10(6)/kg) compared with cyclophosphamide plus G-CSF (3.59 x 10(6)/kg) (P = 0.045). The median yield of CD34+ cells per leukapheresis was almost twice as high in patients receiving IVE (1.94 x 10(6)/kg) compared to cyclophosphamide (1.03 x 10(6)/kg) (P = 0.035). In a univariate analysis of the factors affecting mobilization, the subtype of lymphoma (high-grade NHL) and the mobilization regimen were the only factors associated with high CD34+ cell yield. However, in a multivariate analysis of factors affecting mobilization including age, lymphoma subtype, previous chemotherapy and radiotherapy, only the use of the IVE protocol was predictive of a high yield of CD34+ cells. In 13 patients undergoing a second mobilization procedure the use of IVE was associated with a significantly higher yield of CD34+ cells compared to cyclophosphamide; three patients who failed cyclophosphamide plus G-CSF mobilization were able to proceed to transplantation following successful mobilization with IVE + G-CSF. These results demonstrate that IVE is a highly effective mobilization regimen which is superior to cyclophophamide and has the benefit of being effective salvage therapy for lymphoma patients.

Adult↗

PubMed2001

Mobility difficulties are not only a problem of old age.

BACKGROUND: Lower extremity mobility difficulties often result from common medical conditions and can disrupt both physical and emotional well-being. OBJECTIVES: To assess the national prevalence of mobility difficulties among noninstitutionalized adults and to examine associations with demographic characteristics and other physical and mental health problems. DESIGN: Cross-sectional survey using the 1994-1995 National Health Interview Survey-Disability Supplement (NHIS-D). We constructed measures of minor, moderate, and major lower extremity mobility difficulties using questions about ability to walk, climb stairs, and stand, and use of mobility aids (e.g., canes, wheelchairs). Age and gender adjustment used direct standardization methods in Software for the Statistical Analysis of Correlated Data (SUDAAN). PARTICIPANTS: Noninstitutionalized, civilian U.S. residents aged 18 years and older. National Health Interview Survey sampling weights with SUDAAN provided nationally representative population estimates. RESULTS: An estimated 19 million people (10.1%) reported some mobility difficulty. The mean age of those with minor, moderate, or major difficulty ranged from 59 to 67 years. Of those reporting major difficulties, 32% said their problems began at aged 50 years or younger. Adjusted problem rates were higher among women (11.8%) than men (8.8%), and higher among African American (15.0%) than whites (10.0%). Persons with mobility difficulties were more likely to be poorly educated, living alone, impoverished, obese, and having problems conducting daily activities. Among persons with major mobility difficulties, 30.6% reported being frequently depressed or anxious, compared to 3.8% for persons without mobility difficulties. CONCLUSIONS: Reports of mobility difficulties are common, including among middle-aged adults. Associations with poor performance of daily activities, depression, anxiety, and poverty highlight the need for comprehensive care for persons with mobility problems.

Activities of Daily Living↗

PubMed2001

Persistent mobility deficit in the absence of deficits in activities of daily living: a risk factor for mortality.

OBJECTIVES: To investigate the extent to which self-reported mobility deficit in the absence of impairment in activities of daily living (ADL) is associated with elevated mortality risk. DESIGN: Prospective cohort study, with annual assessments of mobility and ADL status and ongoing monitoring of vital status. SETTING: Population-based cohort drawn from Medicare enrollees in New York City. PARTICIPANTS: One thousand two hundred ninety-eight older adults reporting functional status at baseline (1992-1994) and 2 years later. MEASUREMENTS: Subjects reported mobility (e.g., walking, climbing stairs, and rising from a chair) and ADL (e.g., bathing, toilet use, dressing, grooming, and feeding) limitations. Two-year functional status trajectories were noted. We used two additional follow-up periods, at 2 and 4 years, to examine the likelihood that older people with mobility deficit may face an increased risk of death without first passing through a state of enduring ADL disability. RESULTS: At 2 years, 12.7% had incident mobility deficit without ADL disability, and 21.3% were persistently disabled in mobility without ADL disability. Relative to subjects free of disability at baseline and follow-up, risk of mortality in the incident mobility deficit group was elevated at 2 and 4 years but did not achieve statistical significance. By contrast, for subjects with persistent mobility impairment who did not report ADL impairment, the mortality risk was significantly elevated both at 2 years (relative risk (RR) = 2.5; 95% confidence interval (CI) = 1.1-5.7)) and 4 years (RR = 2.9; 95% CI = 1.7-4.9)) of follow-up. Mortality was significantly elevated in this group in analyses restricted to respondents with no or only one comorbid condition. CONCLUSION: Continuing, self-reported mobility impairment in the absence of ADL deficit is a risk factor for mortality. Older people with self-reported mobility deficit face an increased risk of mortality without first passing through enduring states of ADL disability.

Activities of Daily Living↗

PubMed2002

The role of smoking and other modifiable lifestyle risk factors in maintaining and restoring lower body mobility in middle-aged and older Americans: results from the HRS and AHEAD. Health and Retirement Study. Asset and Health Dynamics Among the Oldest Old.

OBJECTIVES: To analyze the effect of smoking, smoking cessation, and other modifiable risk factors on mobility in middle-aged and older Americans. DESIGN: Panel study; secondary data analysis. SETTING: United States (national sample). PARTICIPANTS: The Health and Retirement Study (HRS) includes data on 12,652 Americans aged 50 to 61 in four waves (1992-1998). The Asset and Health Dynamics Among the Oldest Old (AHEAD) survey followed 8,124 community-dwelling people aged 70 years and older in three waves (1993-1998). MEASUREMENTS: The relationships between the primary outcome measure, lower body mobility (ability to walk several blocks and walk up one flight of stairs without difficulty), and smoking, exercise (HRS only), body mass index (BMI), and alcohol use were estimated in bivariate and multivariate analyses. RESULTS: Not smoking was strongly positively related to mobility, and the relative effects were similar in both panels. Among those with impaired mobility at baseline, not smoking was also strongly related to recovery. In the middle aged, there were consistent dose-response relationships between amount smoked and impaired mobility. Fifteen years after quitting, the risk of impaired mobility returned to that of never smokers. There was also a strong dose-response relationship between level of exercise and mobility. Inverted U-shaped relationships with mobility were observed for BMI and alcohol consumption. CONCLUSIONS: The relationships between not smoking and lower body mobility in middle-aged and older Americans are strong and consistent. Interventions aimed at reducing smoking have the potential to preserve mobility and thereby prolong health and independence in later life.

Age Distribution↗

PubMed2002

Neutrophils are indispensable for hematopoietic stem cell mobilization induced by interleukin-8 in mice.

The CXC chemokine interleukin-8 (IL-8/CXCL8) induces rapid mobilization of hematopoietic progenitor cells (HPCs). Previously we showed that mobilization could be prevented completely in mice by pretreatment with neutralizing antibodies against the beta2-integrin LFA-1 (CD11a). In addition, murine HPCs do not express LFA-1, indicating that mobilization requires a population of accessory cells. Here we show that polymorphonuclear cells (PMNs) serve as key regulators in IL-8-induced HPC mobilization. The role of PMNs was studied in mice rendered neutropenic by administration of a single injection of antineutrophil antibodies. Absolute neutropenia was observed up to 3-5 days with a rebound neutrophilia at day 7. The IL-8-induced mobilizing capacity was reduced significantly during the neutropenic phase, reappeared with recurrence of the PMNs, and was increased proportionally during the neutrophilic phase. In neutropenic mice, the IL-8-induced mobilizing capacity was restored by the infusion of purified PMNs but not by infusion of mononuclear cells. Circulating metalloproteinase gelatinase B (MMP-9) levels were detectable only in neutropenic animals treated with PMNs in combination with IL-8, showing that in vivo activated PMNs are required for the restoration of mobilization. However, IL-8-induced mobilization was not affected in MMP-9-deficient mice, indicating that MMP-9 is not indispensable for mobilization. These data demonstrate that IL-8-induced mobilization of HPCs requires the in vivo activation of circulating PMNs.

Animals↗