I developed a weeding-duration model for Sakhalin fir （Abies sachalinensis （Fr. Schmidt） Masters） plantations that employs a generalized linear model. The number of years following planting that weeding is necessa...I developed a weeding-duration model for Sakhalin fir （Abies sachalinensis （Fr. Schmidt） Masters） plantations that employs a generalized linear model. The number of years following planting that weeding is necessary is the response variable, and elevation, slope steepness, maximum snow depth, annual precipitation, geology, soil, site index, slope aspect, and vegetation type are explanatory variables. Among the explanatory variables, geology, soil, slope aspect, and vegetation type are categorical data. A Poisson distribution is assumed for the response variable, with a log-link function. Elevation, slope steepness, maximum snow depth, annual precipitation, site index, and vegetation type had a significant effect on weeding duration. Among the eight models with the smallest Akaike information criterion （AIC）, I chose the model with no multicollinearity among the explanatory variables. The weeding-duration model includes site index, maximum snow depth, slope steepness （angle） and vegetation type as explanatory variables; elevation and annual precipitation were not included in the selected model because of multicollinearity with maximum snow depth. This model is useful for cost-benefit analyses of afforestation or reforestation with Abies sachalinensis.展开更多
Background: Peripheral artery disease (PAD) is the least recognized form of atherosclerosis and may even result in amputation if the diagnosis is delayed. Manual pulse palpation is the traditional way to diagnose PAD....Background: Peripheral artery disease (PAD) is the least recognized form of atherosclerosis and may even result in amputation if the diagnosis is delayed. Manual pulse palpation is the traditional way to diagnose PAD. Doppler ultrasonographic measurement of ankle-brachial index (ABI) is the gold standard diagnosing method but requires training and is not necessarily available as an outpatient procedure. Using automated oscillometric blood pressure devices has been suggested as an easier method for measuring the ABI. Methods: A single observer palpated the arterial dorsalis pedis, examined hand joints and measured the ABI of one hundred diabetic patients using both Doppler and oscillometric methods. The purpose of this study was to compare the oscillometric method and the manual diagnosing methods to the gold standard method of using a hand held Doppler device for measuring the ABI and detecting PAD. Results: ABI was abnormal in 24 patients (24%) (22 males, 2 females) when measured with the Doppler method. Of these 24 patients, the oscillometric method would have missed 12 giving 12 false negatives. We found that the sensitivity of the oscillometric method was 50.0% and specificity 90.8%. Clinical examination with palpation of ADP combined with limited joint mobility (LJM) scoring would have missed only four cases. Conclusions: Although the oscillometric method is easy and accessible, it is not sensitive enough to be used as the only method in measuring ABI. The simple and inexpensive ADP pulse palpation combined with testing for LMJ was able to find 20 of the 24 (83%) patients with an abnormal ABI measured by Doppler stethoscope.展开更多
BACKGROUND: Ankle brachial index (ABI) is widely involved in researches and clinical application of peripheral vascular injury of patients with diabetes mellitus (DM); however, the application in cerebral infarction (...BACKGROUND: Ankle brachial index (ABI) is widely involved in researches and clinical application of peripheral vascular injury of patients with diabetes mellitus (DM); however, the application in cerebral infarction (CI) is rare. OBJECTIVE: To investigate the possible risk factor of cerebral infarction plus peripheral arterial disease (PAD), compare metabolic characteristics of patients who having CI plus PAD or only having CI, and understand the significance of ABI on screening and diagnosing CI plus PAD of lower limb. DESIGN: Contrast observation based on CI patients. SETTING: Department of Neurology, Nanxishan Hospital of Guangxi Zhuang Autonomous Region. PARTICIPANTS: A total of 124 CI patients were selected from Department of Neurology, Nanxishan Hospital of Guangxi Zhuang Autonomous Region from July 2005 to April 2006, including 72 males and 52 females aged from 45 to 88 years. All patients met the diagnostic criteria of cerebrovascular disease established by National Academic Conference of Cerebrovascular Diseases in 1995 and determined as cerebral infarction with MRI or CT examination. All patients provided informed consent. There were 46 cases (37.2%) with CI plus PAD and 78 cases (62.8%) only with CI. METHODS: Blood pressure of bilateral ankles and upper extremities was measured at plain clinostatism with DINAMAP blood pressure monitor (GE Company). The ratio between average systolic pressure of lateral ankle and average systolic pressure of both upper extremities was regarded as ABI. The normal ABI was equal to or more than 0.9. If ABI < 0.9 occurred at one side, patients were diagnosed as PAD. On the second morning after hospitalization, blood was collected to measure fasting blood glucose (FBG), 2-hour postprandial blood glucose (PBG2h), glycosylated hemoglobin (HbA1c), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Among them, blood glucose, lipid and other biochemical markers were measured with enzyme chemistry assay and HbA1c was measured with HbA1c meter based on high liquid phase. Measurement data and enumeration data were compared with t test and Chi-square test, and multiple factors were dealt with Logistic regression analysis and multivariate linear regression analysis. MAIN OUTCOME MEASURES: Results of correlation between ABI and metabolic markers with multivariate linear regression analysis; risk factors of CI plus PAD with Logistic regression analysis; comparisons of metabolic markers between PAD and non-PAD patients. RESULTS: All 124 patients with acute CI were involved in the final analysis. ① Comparisons of metabolic markers: Levels of serum LDL-C and uric acid (UA) were higher of PAD patients than those of non-PAD patients (t =2.051 9, 3.339 1, P < 0.05); however, there were no significant differences among other metabolic markers (P > 0.05). ② Results of multivariate linear regression analysis: PBG2h, LDL-C and UA were obvious correlation with ABI of posterior tibial artery of lower limb and dorsal pedis artery (partial regression coefficient = -0.231 to -1.010, P < 0.05). ③ Risk factors of CI plus PAD with Logistic regression analysis: Age, smoking history, sum of CI focus (≥3) and LDL-C were independent risk factor of CI plus PAD (OR =1.524-5.422, P < 0.05-0.01). CONCLUSION: ① Levels of serum LDL-C and UA of patients with CI plus PAD are high. ② ABI of lower limbs is correlation with PBG2h, LDL-C and UA. In addition, measuring ABI is beneficial for early diagnosing PAD of lower limbs of patients who have poorly controlled blood glucose, abnormal lipid and poor renal function. ③ Age, LDL-C and sum of CI focus (≥3) are independent risk factors of CI plus PAD. It is of significance for screening non-PAD patients to evaluate risk degrees and prognosis and select therapeutic methods based on ABI measurement.展开更多
Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and...Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and is associated with an increased risk of coronary heart disease, stroke, and leg amputation. The first-line method for diagnosis of PAD is the Ankle Brachial Index (ABI), which is the ratio of ankle to brachial higher systolic pressure measured in ankles and arms. The Toe Brachial Index (TBI), which is the ratio of the toe systolic pressure to brachial higher systolic pressure measured in both arms, is considered to be an alternative to the ABI in screening for PAD. The ABI and TBI are measured on the right and left side, and the lower of these numbers is the patient’s overall ABI and TBI. Clinical studies and meta-analysis reviews have shown that the conventional ABI measurement, which uses a cuff, and handheld sphygmomanometer and continuous-wave Doppler tracings, provides an acceptable-to-high specificity level but low sensitivity when compared with vascular color Doppler ultrasound, and/or angiography methods. Another study has shown that the TBI measurement has greater sensitivity but lower specificity than the ABI when compared with vascular color Doppler ultrasound diagnostic based on waveforms. The aim of this clinical study was to evaluate the specificity and sensitivity of the VasoPad System comparing its results to the vascular color doppler ultrasound waveforms. Materials and Methods: The VasoPad System is an automated device using the pulse wave method to measure the arms and ankles dorsalis and tibial posterior artery blood pressures, the photoplethysmography second derivative (PTGSD) to estimate the toe systolic pressure, a patented photoplethysmography (PTG) index marker and volume plethysmography via cuffs during deflation. Vascular Color Doppler ultrasound can diagnose stenosis through the direct visualization of atherosclerosis or plaques and through waveform analysis. The vascular color Doppler ultrasound provides 3 waveform types. The type 1, triphasic waveform is normal blood flow and no atherosclerosis or plaque, the type 2, diphasic waveform is seen when there are atherosclerosis plaques, but normal blood flow, and the type 3, monophasic waveform reflects stenosis with diameter reduction > 50%. Results: The sum of the overall ABI and TBI VasoPad values, called Sum of Brachial Indices (SBI), gave a specificity of 88.89% and sensitivity of 100% for detecting vascular color Doppler ultrasound biphasic and monophasic waveforms versus triphasic waveforms with a cutoff ≤ 1.36 (P Conclusion: The VasoPad was useful for detecting PAD, which is fully defined as having vessel stenosis > 50% (Doppler monophasic waveforms) but also early stage of atherosclerosis plaque of the lower extremities (Doppler biphasic waveforms). The VasoPad method provided a remarkable sensitivity of 100% and a specificity level similar to those of the conventional ABI test method compared with the vascular color Doppler ultrasound. In addition to being useful to screen and detect PAD, the VasoPad offers early detection of lower extremity atherosclerosis, with normal blood flow (Doppler biphasic waveforms), which could provide greater treatment options and thus reduce the overall number of lower extremity complications.展开更多
文摘I developed a weeding-duration model for Sakhalin fir （Abies sachalinensis （Fr. Schmidt） Masters） plantations that employs a generalized linear model. The number of years following planting that weeding is necessary is the response variable, and elevation, slope steepness, maximum snow depth, annual precipitation, geology, soil, site index, slope aspect, and vegetation type are explanatory variables. Among the explanatory variables, geology, soil, slope aspect, and vegetation type are categorical data. A Poisson distribution is assumed for the response variable, with a log-link function. Elevation, slope steepness, maximum snow depth, annual precipitation, site index, and vegetation type had a significant effect on weeding duration. Among the eight models with the smallest Akaike information criterion （AIC）, I chose the model with no multicollinearity among the explanatory variables. The weeding-duration model includes site index, maximum snow depth, slope steepness （angle） and vegetation type as explanatory variables; elevation and annual precipitation were not included in the selected model because of multicollinearity with maximum snow depth. This model is useful for cost-benefit analyses of afforestation or reforestation with Abies sachalinensis.
文摘Background: Peripheral artery disease (PAD) is the least recognized form of atherosclerosis and may even result in amputation if the diagnosis is delayed. Manual pulse palpation is the traditional way to diagnose PAD. Doppler ultrasonographic measurement of ankle-brachial index (ABI) is the gold standard diagnosing method but requires training and is not necessarily available as an outpatient procedure. Using automated oscillometric blood pressure devices has been suggested as an easier method for measuring the ABI. Methods: A single observer palpated the arterial dorsalis pedis, examined hand joints and measured the ABI of one hundred diabetic patients using both Doppler and oscillometric methods. The purpose of this study was to compare the oscillometric method and the manual diagnosing methods to the gold standard method of using a hand held Doppler device for measuring the ABI and detecting PAD. Results: ABI was abnormal in 24 patients (24%) (22 males, 2 females) when measured with the Doppler method. Of these 24 patients, the oscillometric method would have missed 12 giving 12 false negatives. We found that the sensitivity of the oscillometric method was 50.0% and specificity 90.8%. Clinical examination with palpation of ADP combined with limited joint mobility (LJM) scoring would have missed only four cases. Conclusions: Although the oscillometric method is easy and accessible, it is not sensitive enough to be used as the only method in measuring ABI. The simple and inexpensive ADP pulse palpation combined with testing for LMJ was able to find 20 of the 24 (83%) patients with an abnormal ABI measured by Doppler stethoscope.
文摘BACKGROUND: Ankle brachial index (ABI) is widely involved in researches and clinical application of peripheral vascular injury of patients with diabetes mellitus (DM); however, the application in cerebral infarction (CI) is rare. OBJECTIVE: To investigate the possible risk factor of cerebral infarction plus peripheral arterial disease (PAD), compare metabolic characteristics of patients who having CI plus PAD or only having CI, and understand the significance of ABI on screening and diagnosing CI plus PAD of lower limb. DESIGN: Contrast observation based on CI patients. SETTING: Department of Neurology, Nanxishan Hospital of Guangxi Zhuang Autonomous Region. PARTICIPANTS: A total of 124 CI patients were selected from Department of Neurology, Nanxishan Hospital of Guangxi Zhuang Autonomous Region from July 2005 to April 2006, including 72 males and 52 females aged from 45 to 88 years. All patients met the diagnostic criteria of cerebrovascular disease established by National Academic Conference of Cerebrovascular Diseases in 1995 and determined as cerebral infarction with MRI or CT examination. All patients provided informed consent. There were 46 cases (37.2%) with CI plus PAD and 78 cases (62.8%) only with CI. METHODS: Blood pressure of bilateral ankles and upper extremities was measured at plain clinostatism with DINAMAP blood pressure monitor (GE Company). The ratio between average systolic pressure of lateral ankle and average systolic pressure of both upper extremities was regarded as ABI. The normal ABI was equal to or more than 0.9. If ABI < 0.9 occurred at one side, patients were diagnosed as PAD. On the second morning after hospitalization, blood was collected to measure fasting blood glucose (FBG), 2-hour postprandial blood glucose (PBG2h), glycosylated hemoglobin (HbA1c), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Among them, blood glucose, lipid and other biochemical markers were measured with enzyme chemistry assay and HbA1c was measured with HbA1c meter based on high liquid phase. Measurement data and enumeration data were compared with t test and Chi-square test, and multiple factors were dealt with Logistic regression analysis and multivariate linear regression analysis. MAIN OUTCOME MEASURES: Results of correlation between ABI and metabolic markers with multivariate linear regression analysis; risk factors of CI plus PAD with Logistic regression analysis; comparisons of metabolic markers between PAD and non-PAD patients. RESULTS: All 124 patients with acute CI were involved in the final analysis. ① Comparisons of metabolic markers: Levels of serum LDL-C and uric acid (UA) were higher of PAD patients than those of non-PAD patients (t =2.051 9, 3.339 1, P < 0.05); however, there were no significant differences among other metabolic markers (P > 0.05). ② Results of multivariate linear regression analysis: PBG2h, LDL-C and UA were obvious correlation with ABI of posterior tibial artery of lower limb and dorsal pedis artery (partial regression coefficient = -0.231 to -1.010, P < 0.05). ③ Risk factors of CI plus PAD with Logistic regression analysis: Age, smoking history, sum of CI focus (≥3) and LDL-C were independent risk factor of CI plus PAD (OR =1.524-5.422, P < 0.05-0.01). CONCLUSION: ① Levels of serum LDL-C and UA of patients with CI plus PAD are high. ② ABI of lower limbs is correlation with PBG2h, LDL-C and UA. In addition, measuring ABI is beneficial for early diagnosing PAD of lower limbs of patients who have poorly controlled blood glucose, abnormal lipid and poor renal function. ③ Age, LDL-C and sum of CI focus (≥3) are independent risk factors of CI plus PAD. It is of significance for screening non-PAD patients to evaluate risk degrees and prognosis and select therapeutic methods based on ABI measurement.
文摘Background: Lower extremity Peripheral artery disease (PAD) is caused by atherosclerosis, or Plaque buildup, that reduces the blood flow to the legs and feet. PAD affects approximately 230 million adults worldwide and is associated with an increased risk of coronary heart disease, stroke, and leg amputation. The first-line method for diagnosis of PAD is the Ankle Brachial Index (ABI), which is the ratio of ankle to brachial higher systolic pressure measured in ankles and arms. The Toe Brachial Index (TBI), which is the ratio of the toe systolic pressure to brachial higher systolic pressure measured in both arms, is considered to be an alternative to the ABI in screening for PAD. The ABI and TBI are measured on the right and left side, and the lower of these numbers is the patient’s overall ABI and TBI. Clinical studies and meta-analysis reviews have shown that the conventional ABI measurement, which uses a cuff, and handheld sphygmomanometer and continuous-wave Doppler tracings, provides an acceptable-to-high specificity level but low sensitivity when compared with vascular color Doppler ultrasound, and/or angiography methods. Another study has shown that the TBI measurement has greater sensitivity but lower specificity than the ABI when compared with vascular color Doppler ultrasound diagnostic based on waveforms. The aim of this clinical study was to evaluate the specificity and sensitivity of the VasoPad System comparing its results to the vascular color doppler ultrasound waveforms. Materials and Methods: The VasoPad System is an automated device using the pulse wave method to measure the arms and ankles dorsalis and tibial posterior artery blood pressures, the photoplethysmography second derivative (PTGSD) to estimate the toe systolic pressure, a patented photoplethysmography (PTG) index marker and volume plethysmography via cuffs during deflation. Vascular Color Doppler ultrasound can diagnose stenosis through the direct visualization of atherosclerosis or plaques and through waveform analysis. The vascular color Doppler ultrasound provides 3 waveform types. The type 1, triphasic waveform is normal blood flow and no atherosclerosis or plaque, the type 2, diphasic waveform is seen when there are atherosclerosis plaques, but normal blood flow, and the type 3, monophasic waveform reflects stenosis with diameter reduction > 50%. Results: The sum of the overall ABI and TBI VasoPad values, called Sum of Brachial Indices (SBI), gave a specificity of 88.89% and sensitivity of 100% for detecting vascular color Doppler ultrasound biphasic and monophasic waveforms versus triphasic waveforms with a cutoff ≤ 1.36 (P Conclusion: The VasoPad was useful for detecting PAD, which is fully defined as having vessel stenosis > 50% (Doppler monophasic waveforms) but also early stage of atherosclerosis plaque of the lower extremities (Doppler biphasic waveforms). The VasoPad method provided a remarkable sensitivity of 100% and a specificity level similar to those of the conventional ABI test method compared with the vascular color Doppler ultrasound. In addition to being useful to screen and detect PAD, the VasoPad offers early detection of lower extremity atherosclerosis, with normal blood flow (Doppler biphasic waveforms), which could provide greater treatment options and thus reduce the overall number of lower extremity complications.
