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Chu S.,University of California at Los Angeles | Boxer R.,University of California at Los Angeles | Madison P.,Veterans Affairs Greater Los Angeles | Kleinman L.,Veterans Affairs Greater Los Angeles | And 5 more authors.
Urology | Year: 2015

Objective To report the use of telemedicine to deliver general urologic care to remote locations within the Veterans Affairs Greater Los Angeles Healthcare System. We describe the diagnoses managed, patient satisfaction, safety, and benefit to patients in terms of saved travel time and expense. Methods We conducted a retrospective chart review examining care delivered through urology telemedicine clinics over a 6-month period. We examined the urologic conditions, patient satisfaction, and emergency department visits within 30 days of the visit. We estimated patient benefit by calculating travel distance and time and the saved travel-associated costs using Google Maps and US Census income data. Results Ninety-seven unique telemedicine visits were conducted and a total of 171 urologic diseases were assessed. The most common conditions were lower urinary tract symptoms (35%), elevated prostate-specific antigen level (15%), and prostate cancer (14%). One patient was seen in the emergency department within 30 days with an unpreventable urologic complaint. Patient satisfaction was "very good" to "excellent" in 95% of cases, and 97% would refer another veteran to the urology telemedicine clinic. Patients saved an average of 277 travel miles, 290 minutes of travel time, $67 in travel expenses, and $126 in lost opportunity cost. Conclusion Telemedicine was successfully and safely used to evaluate and treat a wide range of urologic conditions within the Veterans Affairs Greater Los Angeles Healthcare System, and saves patients nearly 5 hours and up to $193 per visit. Further investigation of the potential of telemedicine for the delivery of urologic care in a cost-effective manner is warranted. © 2015 Elsevier Inc.

St. Charles F.K.,St. Charles Consultancy | McAughey J.,and nter | Shepperd C.J.,and nter
Inhalation Toxicology | Year: 2013

Methodologies have been developed, described and demonstrated that convert mouth exposure estimates of cigarette smoke constituents to dose by accounting for smoke spilled from the mouth prior to inhalation (mouth-spill (MS)) and the respiratory retention (RR) during the inhalation cycle. The methodologies are applicable to just about any chemical compound in cigarette smoke that can be measured analytically and can be used with ambulatory population studies. Conversion of exposure to dose improves the relevancy for risk assessment paradigms. Except for urinary nicotine plus metabolites, biomarkers generally do not provide quantitative exposure or dose estimates. In addition, many smoke constituents have no reliable biomarkers. We describe methods to estimate the RR of chemical compounds in smoke based on their vapor pressure (VP) and to estimate the MS for a given subject. Data from two clinical studies were used to demonstrate dose estimation for 13 compounds, of which only 3 have urinary biomarkers. Compounds with VP > 10-5 Pa generally have RRs of 88% or greater, which do not vary appreciably with inhalation volume (IV). Compounds with VP < 10-7 Pa generally have RRs dependent on IV and lung exposure time. For MS, mean subject values from both studies were slightly greater than 30%. For constituents with urinary biomarkers, correlations with the calculated dose were significantly improved over correlations with mouth exposure. Of toxicological importance is that the dose correlations provide an estimate of the metabolic conversion of a constituent to its respective biomarker. © 2013 Informa Healthcare USA, Inc.

Zelik K.E.,University of Michigan | Collins S.H.,Carnegie Mellon University | Adamczyk P.G.,Intelligent Prosthetic Systems, Llc | Segal A.D.,and nter | And 10 more authors.
IEEE Transactions on Neural Systems and Rehabilitation Engineering | Year: 2011

Lower-limb amputees expend more energy to walk than non-amputees and have an elevated risk of secondary disabilities. Insufficient push-off by the prosthetic foot may be a contributing factor. We aimed to systematically study the effect of prosthetic foot mechanics on gait, to gain insight into fundamental prosthetic design principles. We varied a single parameter in isolation, the energy-storing spring in a prototype prosthetic foot, the controlled energy storage and return (CESR) foot, and observed the effect on gait. Subjects walked on the CESR foot with three different springs. We performed parallel studies on amputees and on non-amputees wearing prosthetic simulators. In both groups, spring characteristics similarly affected ankle and body center-of-mass (COM) mechanics and metabolic cost. Softer springs led to greater energy storage, energy return, and prosthetic limb COM push-off work. But metabolic energy expenditure was lowest with a spring of intermediate stiffness, suggesting biomechanical disadvantages to the softest spring despite its greater push-off. Disadvantages of the softest spring may include excessive heel displacements and COM collision losses. We also observed some differences in joint kinetics between amputees and non-amputees walking on the prototype foot. During prosthetic push-off, amputees exhibited reduced energy transfer from the prosthesis to the COM along with increased hip work, perhaps due to greater energy dissipation at the knee. Nevertheless, the results indicate that spring compliance can contribute to push-off, but with biomechanical trade-offs that limit the degree to which greater push-off might improve walking economy. © 2011 IEEE.

Segal A.D.,and nter | Zelik K.E.,University of Michigan | Klute G.K.,and nter | Klute G.K.,University of Washington | And 12 more authors.
Human Movement Science | Year: 2012

The lack of functional ankle musculature in lower limb amputees contributes to the reduced prosthetic ankle push-off, compensations at other joints and more energetically costly gait commonly observed in comparison to non-amputees. A variety of energy storing and return prosthetic feet have been developed to address these issues but have not been shown to sufficiently improve amputee biomechanics and energetic cost, perhaps because the timing and magnitude of energy return is not controlled. The goal of this study was to examine how a prototype microprocessor-controlled prosthetic foot designed to store some of the energy during loading and return it during push-off affects amputee gait. Unilateral transtibial amputees wore the Controlled Energy Storage and Return prosthetic foot (CESR), a conventional foot (CONV), and their previously prescribed foot (PRES) in random order. Three-dimensional gait analysis and net oxygen consumption were collected as participants walked at constant speed. The CESR foot demonstrated increased energy storage during early stance, increased prosthetic foot peak push-off power and work, increased prosthetic limb center of mass (COM) push-off work and decreased intact limb COM collision work compared to CONV and PRES. The biological contribution of the positive COM work for CESR was reduced compared to CONV and PRES. However, the net metabolic cost for CESR did not change compared to CONV and increased compared to PRES, which may partially reflect the greater weight, lack of individualized size and stiffness and relatively less familiarity for CESR and CONV. Controlled energy storage and return enhanced prosthetic push-off, but requires further design modifications to improve amputee walking economy. © 2011.

Morgenroth D.C.,and nter | Morgenroth D.C.,University of Washington | Segal A.D.,and nter | Zelik K.E.,University of Michigan | And 12 more authors.
Gait and Posture | Year: 2011

Lower extremity amputation not only limits mobility, but also increases the risk of knee osteoarthritis of the intact limb. Dynamic walking models of non-amputees suggest that pushing-off from the trailing limb can reduce collision forces on the leading limb. These collision forces may determine the peak knee external adduction moment (EAM), which has been linked to the development of knee OA in the general population. We therefore hypothesized that greater prosthetic push-off would lead to reduced loading and knee EAM of the intact limb in unilateral transtibial amputees.Seven unilateral transtibial amputees were studied during gait under three prosthetic foot conditions that were intended to vary push-off. Prosthetic foot-ankle push-off work, intact limb knee EAM and ground reaction impulses for both limbs during step-to-step transition were measured.Overall, trailing limb prosthetic push-off work was negatively correlated with leading intact limb 1st peak knee EAM (slope = -72 ± .22; p=.011). Prosthetic push-off work and 1st peak intact knee EAM varied significantly with foot type. The prosthetic foot condition with the least push-off demonstrated the largest knee EAM, which was reduced by 26% with the prosthetic foot producing the most push-off. Trailing prosthetic limb push-off impulse was negatively correlated with leading intact limb loading impulse (slope = -34 ± .14; p=.001), which may help explain how prosthetic limb push-off can affect intact limb loading.Prosthetic feet that perform more prosthetic push-off appear to be associated with a reduction in 1st peak intact knee EAM, and their use could potentially reduce the risk and burden of knee osteoarthritis in this population. © 2011 Elsevier B.V.

Kaur N.,University of Montréal | Lacasse M.,Imperial Tobacco Canada Ltd. | Roy J.-P.,Imperial Tobacco Canada Ltd. | Cabral J.-L.,Imperial Tobacco Canada Ltd. | And 5 more authors.
Inhalation Toxicology | Year: 2010

The Borgwaldt RM20S® smoking machine enables the generation, dilution, and transfer of fresh cigarette smoke to cell exposure chambers, for in vitro analyses. We present a study confirming the precision (repeatability r, reproducibility R) and accuracy of smoke dose generated by the Borgwaldt RM20S® system and delivery to exposure chambers. Due to the aerosol nature of cigarette smoke, the repeatability of the dilution of the vapor phase in air was assessed by quantifying two reference standard gases: methane (CH 4, r between 29.0 and 37.0 and RSD between 2.2% and 4.5%) and carbon monoxide (CO, r between 166.8 and 235.8 and RSD between 0.7% and 3.7%). The accuracy of dilution (percent error) for CH4 and CO was between 6.4% and 19.5% and between 5.8% and 6.4%, respectively, over a 10-1000-fold dilution range. To corroborate our findings, a small inter-laboratory study was carried out for CH4 measurements. The combined dilution repeatability had an r between 21.3 and 46.4, R between 52.9 and 88.4, RSD between 6.3% and 17.3%, and error between 4.3% and 13.1%. Based on the particulate component of cigarette smoke (3R4F), the repeatability (RSD=12%) of the undiluted smoke generated by the Borgwaldt RM20S® was assessed by quantifying solanesol using high-performance liquid chromatography with ultraviolet detection (HPLC/UV). Finally, the repeatability (r between 0.98 and 4.53 and RSD between 8.8% and 12%) of the dilution of generated smoke particulate phase was assessed by quantifying solanesol following various dilutions of cigarette smoke. The findings in this study suggest the Borgwaldt RM20S® smoking machine is a reliable tool to generate and deliver repeatable and reproducible doses of whole smoke to in vitro cultures. © 2010 Informa Healthcare USA, Inc.

Liu C.,and nter | McAdam K.G.,and nter | Perfetti T.A.,Perfetti and Perfetti LLC
Mini-Reviews in Organic Chemistry | Year: 2011

This short review summarises some fundamental aspects of cigarette combustion and smoke formation, including how cigarettes burn, how cigarette smoke is formed and the complex and reactive nature of its composition. Particular emphasis has been placed on important factors which have to be controlled when generating, trapping and analyzing cigarette smoke. Examples are provided which demonstrate the sensitivity of cigarette smoke composition to the way it is produced and measured, a subject of particular importance for redox sensitive species such as free radicals and multiple valency-state metals. Recent regulatory interest in smoke constituent yields is summarized, as well as risk assessment approaches which have sought to identify the smoke constituents which make the greatest contribution to smoking related diseases. Limitations of these approaches are discussed, and a number of other aspects of cigarette smoke that have been suggested to contribute to the incidence of smoking related diseases are highlighted. © 2011 Bentham Science Publishers.

Segal A.D.,and nter | Shofer J.,and nter | Hahn M.E.,and nter | Orendurff M.S.,Orthocare Innovations Inc. | And 2 more authors.
Journal of Bone and Joint Surgery - Series A | Year: 2012

Background: Ankle arthritis, like hip and knee arthritis, has a substantial impact on patient function. Understanding the functional limitations of ankle arthritis may help to stratify treatment strategies. Methods: We measured the preoperative demographic characteristics, physical function, and self-assessed function of patients with end-stage ankle arthritis and identified correlations among these metrics. Participants wore a StepWatch 3 Activity Monitor for two weeks and completed the Musculoskeletal Function Assessment and Short Form-36 surveys. Gait kinematics and kinetics were also measured as participants walked at a self-selected pace. Results: Musculoskeletal Function Assessment and Short Form-36 scores revealed reduced perceived function for patients with end-stage ankle arthritis compared with healthy controls. These patients also took fewer total steps per day, took fewer high-intensity steps, and chose to walk at a slower walking speed. Gait analysis revealed reduced ankle motion, peak ankle plantar flexor moment, peak ankle power absorbed, and peak ankle power generated for the affected limb compared with the unaffected limb. High-intensity step count was also correlated with both survey scores, walking speed, step length, peak ankle plantar flexor moment, and peak ankle power generated. Walking speed, step length, and ankle motion were correlated with peak ankle plantar flexor moment and power generated. Conclusions: Generally, patients with end-stage ankle arthritis have reduced physical and perceived function compared with healthy individuals. Additionally, high-intensity step count was a better indicator of physical and perceived function compared with total steps per day for this population. Clinical Relevance: Functional impairments related to ankle arthritis are substantial. In addition, significant associations among perceived function, sustained high-intensity step count, and certain gait variables can further define the utility of these outcome measurements in this patient population. Copyright © 2012 by The Journal of Bone and Joint Surgery, Incorporated.

Asgharian B.,NC Associates | Price O.T.,NC Associates | Yurteri C.U.,and nter | Dickens C.,and nter | McAughey J.,and nter
Inhalation Toxicology | Year: 2014

Inhalation of cigarette smoke particles (CSP) leads to adverse health effects in smokers. Determination of the localized dose to the lung of the inhaled smoke aids in determining vulnerable sites, and identifying components of the smoke that may be responsible for the adverse effects; thus providing a roadmap for harm reduction of cigarette smoking. A particle deposition model specific to CSP was developed for the oral cavity and the lung by accounting for cigarette particle size growth by hygroscopicity, phase change and coagulation. In addition, since the cigarette puff enters the respiratory tract as a dense cloud, the cloud effect on particle drag and deposition was accounted for in the deposition model. Models of particle losses in the oral cavities were developed during puff drawing and subsequent mouth-hold. Cigarette particles were found to grow by hygroscopicity and coagulation, but to shrink as a result of nicotine evaporation. The particle size reached a plateau beyond which any disturbances in the environmental conditions caused the various mechanisms to balance each other out and the particle size remain stable. Predicted particle deposition considering the cloud effects was greater than when treated as a collection of non-interacting particles (i.e. no cloud effects). Accounting for cloud movement provided the necessary physical mechanism to explain the greater than expected, experimentally observed and particle deposition. The deposition model for CSP can provide the necessary input to determine the fate of inhaled CSP in the lung. The knowledge of deposition will be helpful for health assessment and identification and reduction of harmful components of CSP. © 2014 Informa Healthcare USA, Inc.

Forster M.,and nter | Liu C.,and nter | Duke M.G.,and nter | McAdam K.G.,and nter | Proctor C.J.,and nter
Chemistry Central Journal | Year: 2015

Background: Cigarette smoke emissions are mainly produced by distillation, pyrolysis and combustion reactions when the tobacco is burnt. Some studies have shown that heating tobacco to temperatures below pyrolysis and combustion temperatures has the potential to reduce or eliminate some toxicants found in cigarette smoke. In this study, we designed a bench-top tube furnace that heats tobacco between 100-200°C and systematically studied the effects of heating temperatures on selected gas phase and aerosol phase compounds using an ISO machine-smoking protocol. Results: Among a list of target chemical compounds, seven toxicants (nicotine, carbon monoxide, acetaldehyde, crotonaldehyde, formaldehyde, NNN and NNK) were quantifiable but not at all temperatures examined. The levels of the compounds generally displayed an increasing trend with increasing temperatures. The observed carbon monoxide and aldehydes represented the initial thermal breakdown products from the tobacco constituents. Water was the largest measured component in the total aerosol phase collected and appeared to be mainly released by evaporation; nicotine release characteristics were consistent with bond breaking and evaporation. Quantifiable levels of NNK and NNN were thought to be the result of evaporative transfer from the tobacco blend. Conclusions: These results demonstrate the practical utility of this tool to study low-temperature toxicant formation and emission from heated tobacco. Between 100 to 200°C, nicotine and some cigarette smoke compounds were released as a result of evaporative transfer or initial thermal decomposition from the tobacco blend. © Forster et al.; licensee Springer.

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