10 resultados para 6-MINUTE WALK TEST

em DigitalCommons@The Texas Medical Center


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The purpose of this study was to determine if walking a dog would increase motivation to adhere to a walking program and result in an increase in walking endurance and mobility among institutionalized elderly. An experimental pre and post test two group randomly assigned study design was utilized. Thirty subjects, 20 females and 10 males with an average age of 72, were enrolled from three long-term care facilities. The walking program was 3 times a week for 6 weeks. The experimental group walked with a certified therapy dog and the handler. The control group walked with only the handler. The Outcome Expectations for Exercise Scale (OEES) was used to measure the perceived benefits of exercise. The 2-minute walk test and the 30 second chair stand test were administered before and after the walking program. The OEES scores did not significantly predict adherence to the program. The pre- and post-chair stand test and the 2-minute walk test did not show statistical significant differences between groups. All of the participants did show an increase (7 minutes) in walking time during the 6 week period (p=0.048). The mean pre and post walk test scores for participants with stroke/arthritis were significantly less than those without stroke/arthritis (p=0.013). The experimental group had 12 subjects with stroke/arthritis compared with 6 in the control group. The walk test means in feet walked were 362.44 ± 130.36 (control) vs. 201.27 ± 106.25 (experimental), p=0.001. The results indicate walking practice has the potential to increase walking time and endurance. Because residents of long-term care facilities were not allowed outside the facilities without accompaniment, the presence of the dog handler was key to their walking. Analysis of conversations during the walks indicated that for participants who walked with dogs, the dogs did serve as motivation for continuing in the program. ^

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Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease caused by germline mutations in DNA mismatch repair(MMR) genes. The nucleotide excision repair(NER) pathway plays a very important role in cancer development. We systematically studied interactions between NER and MMR genes to identify NER gene single nucleotide polymorphism (SNP) risk factors that modify the effect of MMR mutations on risk for cancer in HNPCC. We analyzed data from polymorphisms in 10 NER genes that had been genotyped in HNPCC patients that carry MSH2 and MLH1 gene mutations. The influence of the NER gene SNPs on time to onset of colorectal cancer (CRC) was assessed using survival analysis and a semiparametric proportional hazard model. We found the median age of onset for CRC among MMR mutation carriers with the ERCC1 mutation was 3.9 years earlier than patients with wildtype ERCC1(median 47.7 vs 51.6, log-rank test p=0.035). The influence of Rad23B A249V SNP on age of onset of HNPCC is age dependent (likelihood ratio test p=0.0056). Interestingly, using the likelihood ratio test, we also found evidence of genetic interactions between the MMR gene mutations and SNPs in ERCC1 gene(C8092A) and XPG/ERCC5 gene(D1104H) with p-values of 0.004 and 0.042, respectively. An assessment using tree structured survival analysis (TSSA) showed distinct gene interactions in MLH1 mutation carriers and MSH2 mutation carriers. ERCC1 SNP genotypes greatly modified the age onset of HNPCC in MSH2 mutation carriers, while no effect was detected in MLH1 mutation carriers. Given the NER genes in this study play different roles in NER pathway, they may have distinct influences on the development of HNPCC. The findings of this study are very important for elucidation of the molecular mechanism of colon cancer development and for understanding why some mutation carriers of the MSH2 and MLH1 gene develop CRC early and others never develop CRC. Overall, the findings also have important implications for the development of early detection strategies and prevention as well as understanding the mechanism of colorectal carcinogenesis in HNPCC. ^

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Mesenchymal stromal cell (MSC) therapy has shown promise for the treatment of traumatic brain injury (TBI). Although the mechanism(s) by which MSCs offer protection is unclear, initial in vivo work has suggested that modulation of the locoregional inflammatory response could explain the observed benefit. We hypothesize that the direct implantation of MSCs into the injured brain activates resident neuronal stem cell (NSC) niches altering the intracerebral milieu. To test our hypothesis, we conducted initial in vivo studies, followed by a sequence of in vitro studies. In vivo: Sprague-Dawley rats received a controlled cortical impact (CCI) injury with implantation of 1 million MSCs 6 h after injury. Brain tissue supernatant was harvested for analysis of the proinflammatory cytokine profile. In vitro: NSCs were transfected with a firefly luciferase reporter for NFkappaB and placed in contact culture and transwell culture. Additionally, multiplex, quantitative PCR, caspase 3, and EDU assays were completed to evaluate NSC cytokine production, apoptosis, and proliferation, respectively. In vivo: Brain supernatant analysis showed an increase in the proinflammatory cytokines IL-1alpha, IL-1beta, and IL-6. In vitro: NSC NFkappaB activity increased only when in contact culture with MSCs. When in contact with MSCs, NSCs show an increase in IL-6 production as well as a decrease in apoptosis. Direct implantation of MSCs enhances neuroprotection via activation of resident NSC NFkappaB activity (independent of PI3 kinase/AKT pathway) leading to an increase in IL-6 production and decrease in apoptosis. In addition, the observed NFkappaB activity depends on direct cell contact.

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BACKGROUND: Follow-up of abnormal outpatient laboratory test results is a major patient safety concern. Electronic medical records can potentially address this concern through automated notification. We examined whether automated notifications of abnormal laboratory results (alerts) in an integrated electronic medical record resulted in timely follow-up actions. METHODS: We studied 4 alerts: hemoglobin A1c > or =15%, positive hepatitis C antibody, prostate-specific antigen > or =15 ng/mL, and thyroid-stimulating hormone > or =15 mIU/L. An alert tracking system determined whether the alert was acknowledged (ie, provider clicked on and opened the message) within 2 weeks of transmission; acknowledged alerts were considered read. Within 30 days of result transmission, record review and provider contact determined follow-up actions (eg, patient contact, treatment). Multivariable logistic regression models analyzed predictors for lack of timely follow-up. RESULTS: Between May and December 2008, 78,158 tests (hemoglobin A1c, hepatitis C antibody, thyroid-stimulating hormone, and prostate-specific antigen) were performed, of which 1163 (1.48%) were transmitted as alerts; 10.2% of these (119/1163) were unacknowledged. Timely follow-up was lacking in 79 (6.8%), and was statistically not different for acknowledged and unacknowledged alerts (6.4% vs 10.1%; P =.13). Of 1163 alerts, 202 (17.4%) arose from unnecessarily ordered (redundant) tests. Alerts for a new versus known diagnosis were more likely to lack timely follow-up (odds ratio 7.35; 95% confidence interval, 4.16-12.97), whereas alerts related to redundant tests were less likely to lack timely follow-up (odds ratio 0.24; 95% confidence interval, 0.07-0.84). CONCLUSIONS: Safety concerns related to timely patient follow-up remain despite automated notification of non-life-threatening abnormal laboratory results in the outpatient setting.

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Adenosine is a purinergic signaling molecule that regulates various aspects of inflammation and has been implicated in the pathogenesis of chronic lung diseases. Previous studies have demonstrated that adenosine up-regulates IL-6 production through the engagement of the A2B adenosine receptor in various cell types, including alveolar macrophages. IL-6 is elevated in mouse models and humans with chronic lung disease, suggesting a potential role in disease progression. Furthermore, chronic elevation of adenosine in the lungs of adenosine deaminase deficient (Ada-/-) mice leads to the development of pulmonary inflammation, alveolar destruction, and fibrosis, in conjunction with IL-6 elevation. Thus, it was hypothesized that IL-6 contributes to pulmonary inflammation and fibrosis in this model. To test this hypothesis, Ada/IL-6 double knockout mice (Ada/IL-6-/-) were generated to assess the consequences of genetically removing IL-6 on adenosine-dependent pulmonary injury. Ada/IL-6-/- mice exhibited a significant reduction in inflammation, alveolar destruction, and pulmonary fibrosis. Next, Ada-/- mice were treated systematically with IL-6 neutralizing antibodies to test the efficacy of blocking IL-6 on chronic lung disease. These treatments were associated with decreased pulmonary inflammation, alveolar destruction, and fibrosis. To determine the role of IL-6 in a second model of pulmonary fibrosis, wild type mice and IL-6-/- mice were subjected to intraperitoneal injections of bleomycin twice a week for four weeks. Results demonstrated that IL-6-/- mice developed reduced pulmonary fibrosis. To examine a therapeutic approach in this model, wild type mice exposed to bleomycin were treated with IL-6 neutralizing antibodies. Similar results were observed as with Ada-/- mice, namely diminished pulmonary inflammation and fibrosis. In both models, elevations in IL-6 were associated with increased phosphorylated STAT-3 in the nuclei of numerous cell types in the airways, including type II alveolar epithelial cells (AEC). Genetic removal and neutralization of IL-6 in both models was associated with decreased STAT-3 activation in type II AEC. The mechanism of activation in these cells that lack the membrane bound IL-6Ra suggests IL-6 trans-signaling may play a role in regulating fibrosis. Characterization of this mechanism demonstrated that the soluble IL-6Ra (sIL-6Ra) is upregulated in both models during chronic conditions. In vitro studies in MLE-12 alveolar epithelial cells confirmed that IL-6, in combination with the sIL-6Ra, activates STAT-3 and TWIST in association with enhancement of epithelial-to-mesenchymal transition, which can contribute to fibrosis. Similarly, patients with idiopathic pulmonary fibrosis demonstrated a similar pattern of increased IL-6 expression, STAT-3 activation, and sIL-6Ra increases. These findings demonstrate that adenosine-dependent elevations in IL-6 contribute to the development and progression of pulmonary inflammation and fibrosis. The implications from these studies are that adenosine and/or IL-6 neutralizing agents represent novel therapeutic targets for the treatment of pulmonary disorders where fibrosis is a detrimental component.

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Background. Polyomavirus reactivation is common in solid-organ transplant recipients who are given immunosuppressive medications as standard treatment of care. Previous studies have shown that polyomavirus infection can lead to allograft failure in as many as 45% of the affected patients. Hypothesis. Ubiquitous polyomaviruses when reactivated by post-transplant immunosuppressive medications may lead to impaired renal function and possibly lower survival prospects. Study Overview. Secondary analysis of data was conducted on a prospective longitudinal study of subjects who were at least 18 years of age and were recipients of liver and/or kidney transplant at Mayo Clinic Scottsdale, Arizona. Methods. DNA extractions of blinded urine and blood specimens of transplant patients collected at Mayo Clinic during routine transplant patient visits were performed at Baylor College of Medicine using Qiagen kits. Virologic assays included testing DNA samples for specific polyomavirus sequences using QPCR technology. De-identified demographic and clinical patient data were merged with laboratory data and statistical analysis was performed using Stata10. Results. 76 patients enrolled in the study were followed for 3.9 years post transplantation. The prevalence of BK virus and JC virus urinary excretion was 30% and 28%. Significant association was observed between JC virus excretion and kidney as the transplanted organ (P = 0.039, Pearson Chi-square test). The median urinary JCV viral loads were two logs higher than those of BKV. Patients that excreted both BKV and JCV appeared to have the worst renal function with a mean creatinine clearance value of 71.6 millimeters per minute. A survival disadvantage was observed for dual shedders of BKV and JCV, log-rank statistics, p = 0.09; 2/5 dual-shedders expired during the study period. Liver transplant and male sex were determined to be potential risk factors for JC virus activation in renal and liver transplant recipients. All patients tested negative for SV40 and no association was observed between polyomavirus excretion and type of immunosuppressive medication (tacrolimus, mycophenolate mofetil, cyclosporine and sirolimus). Conclusions. Polyomavirus reactivation was common after solid-organ transplantation and may be associated with impaired renal function. Male sex and JCV infection may be potential risk factors for viral reactivation; findings should be confirmed in larger studies.^

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This study evaluated the administration-time-dependent effects of a stimulant (Dexedrine 5-mg), a sleep-inducer (Halcion 0.25-mg) and placebo (control) on human performance. The investigation was conducted on 12 diurnally active (0700-2300) male adults (23-38 yrs) using a double-blind, randomized sixway-crossover three-treatment, two-timepoint (0830 vs 2030) design. Performance tests were conducted hourly during sleepless 13-hour studies using a computer generated, controlled and scored multi-task cognitive performance assessment battery (PAB) developed at the Walter Reed Army Institute of Research. Specific tests were Simple and Choice Reaction Time, Serial Addition/Subtraction, Spatial Orientation, Logical Reasoning, Time Estimation, Response Timing and the Stanford Sleepiness Scale. The major index of performance was "Throughput", a combined measure of speed and accuracy.^ For the Placebo condition, Single and Group Cosinor Analysis documented circadian rhythms in cognitive performance for the majority of tests, both for individuals and for the group. Performance was best around 1830-2030 and most variable around 0530-0700 when sleepiness was greatest (0300).^ Morning Dexedrine dosing marginally enhanced performance an average of 3% with reference to the corresponding in time control level. Dexedrine AM also increased alertness by 10% over the AM control. Dexedrine PM failed to improve performance with reference to the corresponding PM control baseline. With regard to AM and PM Dexedrine administrations, AM performance was 6% better with subjects 25% more alert.^ Morning Halcion administration caused a 7% performance decrement and 16% increase in sleepiness and a 13% decrement and 10% increase in sleepiness when administered in the evening compared to corresponding in time control data. Performance was 9% worse and sleepiness 24% greater after evening versus morning Halcion administration.^ These results suggest that for evening Halcion dosing, the overnight sleep deprivation occurring in coincidence with the nadir in performance due to circadian rhythmicity together with the CNS depressant effects combine to produce performance degradation. For Dexedrine, morning administration resulted in only marginal performance enhancement; Dexedrine in the evening was less effective, suggesting the 5-mg dose level may be too low to counteract the partial sleep deprivation and nocturnal nadir in performance. ^

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A simple and inexpensive method is described for analysis of uranium (U) activity and mass in water by liquid scintillation counting using $\alpha$/$\beta$ discrimination. This method appears to offer a solution to the need for an inexpensive protocol for monitoring U activity and mass simultaneously and an alternative to the potential inaccuracy involved when depending on the mass-to-activity conversion factor or activity screen.^ U is extracted virtually quantitatively into 20 ml extractive scintillator from a 1-$\ell$ aliquot of water acidified to less than pH 2. After phase separation, the sample is counted for a 20-minute screening count with a minimum detection level of 0.27 pCi $\ell\sp{-1}$. $\alpha$-particle emissions from the extracted U are counted with close to 100% efficiency with a Beckman LS6000 LL liquid scintillation counter equipped with pulse-shape discrimination electronics. Samples with activities higher than 10 pCi $\ell\sp-1$ are recounted for 500-1000 minutes for isotopic analysis. Isotopic analysis uses events that are automatically stored in spectral files and transferred to a computer during assay. The data can be transferred to a commercially available spreadsheet and retrieved for examination or data manipulation. Values for three readily observable spectral features can be rapidly identified by data examination and substituted into a simple formula to obtain $\sp{234}$U/$\sp{238}$U ratio for most samples. U mass is calculated by substituting the isotopic ratio value into a simple equation.^ The utility of this method for the proposed compliance monitoring of U in public drinking water supplies was field tested with a survey of drinking water from Texas supplies that had previously been known to contain elevated levels of gross $\alpha$ activity. U concentrations in 32 samples from 27 drinking water supplies ranged from 0.26 to 65.5 pCi $\ell\sp{-1}$, with seven samples exceeding the proposed Maximum Contaminant Level of 20 $\mu$g $\ell\sp{-1}$. Four exceeded the proposed activity screening level of 30 pCi $\ell\sp{-1}$. Isotopic ratios ranged from 0.87 to 41.8, while one sample contained $\sp{234}$U activity of 34.6 pCi $\ell\sp{-1}$ in the complete absence of its parent, $\sp{238}$U. U mass in the samples with elevated activity ranged from 0.0 to 103 $\mu$g $\ell\sp{-1}$. A limited test of screening surface and groundwaters for contamination by U from waste sites and natural processes was also successful. ^

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The potential for significant human populations to experience long-term inhalation of formaldehyde and reports of symptomatology due to this exposure has led to a considerable interest in the toxicologic assessment of risk from subchronic formaldehyde exposures using animal models. Since formaldehyde inhalation depresses certain respiratory parameters in addition to its other forms of toxicity, there is a potential for the alteration of the actual dose received by the exposed individual (and the resulting toxicity) due to this respiratory effect. The respiratory responses to formaldehyde inhalation and the subsequent pattern of deposition were therefore investigated in animals that had received subchronic exposure to the compound, and the potential for changes in the formaldehyde dose received due to long-term inhalation evaluated. Male Sprague-Dawley rats were exposed to either 0, 0.5, 3, or 15 ppm formaldehyde for 6 hours/day, 5 days/week for up to 6 months. The patterns of respiratory response, deposition and the compensation mechanisms involved were then determined in a series of formaldehyde test challenges to both the upper and to the lower respiratory tracts in separate groups of subchronically exposed animals and age-specific controls (four concentration groups, two time points). In both the control and pre-exposed animals, there was a characteristic recovery of respiratory parameters initially depressed by formaldehyde inhalation to at or approaching pre-exposure levels within 10 minutes of the initiation of exposure. Also, formaldehyde deposition was found to remain very high in the upper and lower tracts after long-term exposure. Therefore, there was probably little subsequent effect on the dose received by the exposed individual that was attributable to the repeated exposures. There was a diminished initial minute volume response in test challenges of both the upper and lower tracts of animals that had received at least 16 weeks of exposure to 15 ppm, with compensatory increases in tidal volume in the upper tract and respiratory rate in the lower tract. However, this dose-related effect was probably not relevant to human risk estimation because this formaldehyde dose is in excess of that experienced by human populations. ^