Biomedical subjects

Jin Tan

Publications and source records attributed to Jin Tan.

7 recordsLinked to original sources

PubMed2006

Lower extremity nerve function in patients with lower extremity ischemia.

BACKGROUND: We determined whether lower extremity ischemia, as measured by the ankle brachial index (ABI), is associated with impaired lower extremity nerve function. METHODS: Participants included 478 persons with peripheral arterial disease (PAD) identified from noninvasive vascular laboratories and 292 persons without PAD identified from a general medicine practice and noninvasive vascular laboratories. Peripheral arterial disease was defined as an ABI lower than 0.90 (mild PAD: ABI, 0.70 to <0.90; moderate PAD: ABI, 0.50 to <0.70; and severe PAD: ABI, <0.50). The ABI and electrophysiologic measures of the peroneal, sural, and ulnar nerves were obtained. RESULTS: Among 546 participants without diabetes, PAD participants had significantly impaired peripheral nerve function in the upper and lower extremities compared with non-PAD participants. After adjusting for age, sex, race, smoking, height, body mass index, recruitment source, alcohol use, disk disease, spinal stenosis, cardiac disease, and cerebrovascular disease, these associations were not statistically significant. After adjusting for confounders among nondiabetic participants, those with severe PAD (ABI, <0.50) had poorer peroneal nerve conduction velocity (NCV) compared with participants without PAD (42.6 vs 44.8 m/s; P = .003) and poorer peroneal NCV compared with participants with mild PAD (42.6 vs 45.0 m/s; P = .001) or moderate PAD (42.6 vs 44.1 m/s; P = .03). Among 224 participants with diabetes, after adjusting for confounders, PAD was associated with poorer peroneal NCV (40.8 vs 43.5 m/s; P = .01), sural nerve amplitude (3.1 vs 4.8 muV; P = .045), and ulnar NCV (47.6 vs 50.2 m/s; P = .03) compared with those without PAD. CONCLUSIONS: Our findings suggest that leg ischemia impairs peroneal nerve function. This association is less strong in patients with diabetes, perhaps because of the overriding influence of diabetes on peripheral nerve function. Clinicians should consider screening for PAD in patients with idiopathic peroneal nerve dysfunction. Peripheral arterial disease-associated nerve dysfunction may contribute to PAD-associated functional impairment.

Aged↗

PubMed2006

Physical activity during daily life and mortality in patients with peripheral arterial disease.

BACKGROUND: We determined whether patients with lower-extremity peripheral arterial disease (PAD) who are more physically active during daily life have lower mortality rates than PAD patients who are less active. METHODS AND RESULTS: Participants were 460 men and women with PAD (mean age 71.9+/-8.4 years) followed up for 57 months (interquartile range 36.6 to 61.9 months). At baseline, participants were interviewed about their physical activity. Vertical accelerometers measured physical activity continuously over 7 days in 225 participants. Analyses were adjusted for age, sex, race, body mass index, hypertension, smoking, comorbidities, total cholesterol, HDL cholesterol, leg symptoms, and ankle-brachial index. At 57-month follow-up, 134 participants (29%) had died, including 75 participants (33%) who wore accelerometers. Higher baseline physical activity levels measured by vertical accelerometer were associated with lower all-cause mortality (P(trend)=0.003). Relative to PAD participants in the highest quartile of accelerometer-measured physical activity, those in the lowest quartile had higher total mortality (hazard ratio 3.48, 95% confidence interval 1.23 to 9.87, P=0.019). Similar results were observed for the combined outcome of cardiovascular events or cardiovascular mortality (P(trend)=0.005). Higher numbers of stair flights climbed during 1 week were associated with lower total mortality (P(trend)=0.035). CONCLUSIONS: PAD patients with higher physical activity during daily life have reduced mortality and cardiovascular events compared with PAD patients with the lowest physical activity, independent of confounders. Further study is needed to determine whether interventions that increase physical activity during daily life are associated with improved survival in patients with PAD.

Activities of Daily Living↗

PubMed2006

Physical performance in peripheral arterial disease: a slower rate of decline in patients who walk more.

BACKGROUND: Exercise rehabilitation programs increase treadmill walking performance in patients with peripheral arterial disease (PAD) and intermittent claudication. However, it is unknown whether patients with PAD who walk for exercise regularly have less functional decline than those with less walking activity. OBJECTIVE: To determine whether patients with PAD who report that they walk for exercise 3 or more times per week have less annual functional decline than those who walk for exercise less frequently. DESIGN: Prospective cohort study with a median follow-up of 36 months (interquartile range, 24 to 36 months). SETTING: Academic medical center. PARTICIPANTS: 417 men and women with PAD. MEASUREMENTS: Participants were classified at baseline and annually according to the number of times they reportedly walked for exercise each week. Functional assessments (6-minute walk distance, 4-meter walking speed, summary performance score) were measured at baseline and annually. Results were adjusted for age, sex, ethnicity, comorbid conditions, body mass index, ankle-brachial index, education, leg symptoms, cigarette use, geriatric depression score, previous year's level of functioning, and patterns of missing data. RESULTS: Compared with those who exercised less frequently, patients who walked for exercise 3 or more times per week had a significantly smaller average annual decline in 6-minute walking distance (-48.0 feet per year compared with -56.6 feet per year for those who walked 1 to 2 times per week and -79.4 feet per year for nonexercisers; P for trend = 0.037). Patients who walked for exercise at least 3 times per week experienced a smaller average annual decline in the usual-paced 4-meter walking velocity (-0.014 m/s per year compared with -0.022 m/s per year for those who walked 1 to 2 times per week and -0.045 m/s per year for nonexercisers; P = 0.005). Similar findings were observed for the fast-paced 4-meter walk. The subset of asymptomatic patients who walked for exercise 3 or more times per week had annual declines in 6-minute walking performance (P = 0.107), normal-paced walking velocity (P = 0.065), and the summary performance score (P = 0.115); however, these declines were smaller than those observed in asymptomatic participants who walked fewer than 3 times per week. LIMITATIONS: Because this was an observational study, associations reported here cannot be construed as causal relationships. Sample sizes for subgroup analyses were small, which limited statistical power. CONCLUSION: Among patients with PAD, self-directed walking exercise performed at least 3 times weekly is associated with significantly less functional decline during the subsequent year. Similar trends were observed in the subset of asymptomatic patients with PAD. These findings may be particularly important for the numerous patients with PAD who do not have access to supervised walking exercise programs.

Disability Evaluation↗

PubMed2006

Obesity, weight change, and functional decline in peripheral arterial disease.

BACKGROUND: Our objectives were to determine whether obesity is associated with a greater functional decline compared with the ideal body mass index (BMI) among persons with peripheral arterial disease (PAD) and to determine the associations between weight gain and loss and functional declines in PAD. We hypothesized that baseline obesity and weight gain during follow-up would each be associated with functional declines in persons with PAD. METHODS: The design was a prospective cohort study. The subjects were 389 men and women with PAD (mean ankle-brachial index, 0.65 +/- 0.14) who were followed up prospectively for a median of 48 months. The main outcome measures were functional assessments (6-minute walk, usual- and rapid-paced 4-m walking speed, and summary performance score). Weight and height were measured at baseline and annually. Results were adjusted for age, sex, race, comorbidities, ankle-brachial index, education, leg symptoms, exercise status, depressive symptoms, pack-years of cigarette smoking, prior-year functioning, and patterns of missing data. RESULTS: Compared with those with a baseline BMI between 20 and 25 kg/m2, PAD participants with baseline BMI greater than 30 kg/m2 had a significantly greater average annual decline in 6-minute walk performance (-13.1 vs -26.5 m/y; P = .004), usual-paced 4-m walking velocity (-0.028 vs -0.055 m/s per year; P = .024), and fast-paced 4-m walking velocity (-0.053 vs -0.086 m/s per year; P = .012). Persons with weight gain between 5 and 10 pounds after baseline who walked for exercise regularly had significantly less decline in the 6-minute walk than persons without significant weight change who did not walk for exercise (P = .04). CONCLUSIONS: Obesity is associated with functional decline in persons with PAD. Walking exercise may protect against functional decline in PAD persons with modest weight gain.

Aged↗

PubMed2005

An ion-imprinted functionalized silica gel sorbent prepared by a surface imprinting technique combined with a sol-gel process for selective solid-phase extraction of cadmium(II).

A new ion-imprinted thiol-functionalized silica gel sorbent was synthesized by a surface imprinting technique in combination with a sol-gel process for selective on-line, solid-phase extraction of Cd(II). The Cd(II)-imprinted thiol-functionalized silica sorbent was characterized by FT-IR, the static adsorption-desorption experiment, and the dynamic adsorption-desorption method. The maximum static adsorption capacity of the ion-imprinted functionalized sorbent was 284 micromol g(-1). The largest selectivity coefficient for Cd(II) in the presence of Pb(II) was over 220. The static uptake capacity and selectivity coefficient of the ion-imprinted functionalized sorbent are higher than those of the nonimprinted sorbent. The breakthrough capacity and dynamic capacity of the imprinted functionalized silica gel sorbent for 4 mg L(-1) of Cd(II) at 5.2 mL min(-1) of sample flow rate were 11.7 and 64.3 micromol g(-1), respectively. No remarkable effect of sample flow rate on the dynamic capacity was observed as the sample flow rate increased from 1.7 to 6.8 mL min(-1). The imprinted functionalized silica gel sorbent offered a fast kinetics for the adsorption and desorption of Cd(II). The prepared ion-imprinted functionalized sorbent was shown to be promising for on-line, solid-phase extraction coupled with flame atomic absorption spectrometry for the determination of trace cadmium in environmental and biological samples. All competitive ions studied did not interfere with the determination of Cd(II). With a sample loading flow rate of 8.8 mL min(-1) for 45-s preconcentration, an enhancement factor of 56, and a detection limit (3sigma) of 0.07 microg L(-1) were achieved at a sampling frequency of 55 h(-1). The precision (RSD) for 11 replicate on-line sorbent extractions of 8 mug L(-1) Cd(II) was 0.9%. The sorbent also offered good linearity (r = 0.9997) for on-line, solid-phase extraction of trace Cd(II).

Adsorption↗

PubMed2005

Functional decline in lower-extremity peripheral arterial disease: associations with comorbidity, gender, and race.

PURPOSE: To identify comorbidities associated with increased rates of functional decline in persons with lower-extremity peripheral arterial disease (PAD). We also determined whether female sex and black race were associated with greater functional decline than male sex and white race, respectively, in PAD. METHODS: Three-hundred ninety-seven men and women with PAD were followed prospectively for a median of 36 months. The presence of comorbid illnesses was determined with medical record review, patient report, medications, laboratory values, and a primary care physician questionnaire. Functional outcomes, measured annually, included the 6-minute walk, usual-paced and fast-paced 4-meter walking speed, and summary performance score. The summary performance score is a composite measure of lower-extremity functioning (score range, 0 to 12; 12 = best). RESULTS: Adjusting for known and potential confounders, PAD patients with pulmonary disease had a significantly greater average annual decline in 6-minute walk performance of -34.02 ft/y (95% confidence interval [CI], -60.42 to -7.63; P = .012), rapid-paced 4-meter walk speed of -0.028 m/s/y (95% CI, -0.054 to -0.001; P = .042), and summary performance score of -0.460/y (95% CI, -0.762 to -0.157; P = .003) compared with those without pulmonary disease. PAD patients with spinal stenosis had a greater average annual decline in 6-minute walk performance of -77.4 ft/y (95% CI, -18.9 to -35.8; P < .001) and usual-paced 4-meter walking velocity of -0.045 m/s/y (95% CI, -0.081 to -0.009; P = .014) compared with participants without spinal stenosis. CONCLUSION: At 3-year follow-up, pulmonary disease and spinal stenosis were each associated with a significant decline in functioning among persons with PAD. In contrast, female sex and black race were not associated with functional decline among persons with PAD.

Aged↗

PubMed2003

[Treatment of humeral shaft fractures with Russell-Taylor interlocking intramedullar nail].

OBJECTIVE: To evaluate the clinical effects of Russell-Taylor interlocking intramedullar nail (RT nail) on humeral shaft fractures. METHODS: Twenty six patients with humeral shaft fractures were treated with RT nail, of whom 19 cases were treated with antegrade RT nail and 7 cases with retrograde RT nail. RESULTS: With an average of 16 months (range 6-24 months) of follow-up, all cases acquired bony union with mean union time 4.7 months (range 3-8 months). The recovery of shoulder function was excellent in 18 cases, good in 5 cases, and fair in 3 cases. The recovery of elbow function was excellent in 23 cases and good in 3 cases. One case had shoulder impingement caused by proximal locking screw. All cases had no infection, iatrogenic fracture, and peripheral nerve injury. CONCLUSION: RT nail is an effective method for the treatment of humeral shaft fractures.

Adolescent↗